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ee6ba406 | 1 | ------------------------------------------------------------------------------ |
2 | -- -- | |
3 | -- GNAT COMPILER COMPONENTS -- | |
4 | -- -- | |
5 | -- C H E C K S -- | |
6 | -- -- | |
7 | -- B o d y -- | |
8 | -- -- | |
e9c75a1a | 9 | -- Copyright (C) 1992-2019, Free Software Foundation, Inc. -- |
ee6ba406 | 10 | -- -- |
11 | -- GNAT is free software; you can redistribute it and/or modify it under -- | |
12 | -- terms of the GNU General Public License as published by the Free Soft- -- | |
80df182a | 13 | -- ware Foundation; either version 3, or (at your option) any later ver- -- |
ee6ba406 | 14 | -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
15 | -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- | |
16 | -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- | |
17 | -- for more details. You should have received a copy of the GNU General -- | |
80df182a | 18 | -- Public License distributed with GNAT; see file COPYING3. If not, go to -- |
19 | -- http://www.gnu.org/licenses for a complete copy of the license. -- | |
ee6ba406 | 20 | -- -- |
21 | -- GNAT was originally developed by the GNAT team at New York University. -- | |
e78e8c8e | 22 | -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
ee6ba406 | 23 | -- -- |
24 | ------------------------------------------------------------------------------ | |
25 | ||
26 | with Atree; use Atree; | |
29448168 | 27 | with Casing; use Casing; |
ee6ba406 | 28 | with Debug; use Debug; |
29 | with Einfo; use Einfo; | |
7b8fa048 | 30 | with Elists; use Elists; |
31 | with Eval_Fat; use Eval_Fat; | |
32 | with Exp_Ch11; use Exp_Ch11; | |
ee6ba406 | 33 | with Exp_Ch2; use Exp_Ch2; |
df40eeb0 | 34 | with Exp_Ch4; use Exp_Ch4; |
05fcfafb | 35 | with Exp_Pakd; use Exp_Pakd; |
ee6ba406 | 36 | with Exp_Util; use Exp_Util; |
4fb5f0a0 | 37 | with Expander; use Expander; |
ee6ba406 | 38 | with Freeze; use Freeze; |
9dfe12ae | 39 | with Lib; use Lib; |
ee6ba406 | 40 | with Nlists; use Nlists; |
41 | with Nmake; use Nmake; | |
42 | with Opt; use Opt; | |
9dfe12ae | 43 | with Output; use Output; |
c2b56224 | 44 | with Restrict; use Restrict; |
1e16c51c | 45 | with Rident; use Rident; |
ee6ba406 | 46 | with Rtsfind; use Rtsfind; |
47 | with Sem; use Sem; | |
d60c9ff7 | 48 | with Sem_Aux; use Sem_Aux; |
00f91aef | 49 | with Sem_Ch3; use Sem_Ch3; |
9dfe12ae | 50 | with Sem_Ch8; use Sem_Ch8; |
7e933b61 | 51 | with Sem_Disp; use Sem_Disp; |
7b8fa048 | 52 | with Sem_Eval; use Sem_Eval; |
becb6111 | 53 | with Sem_Mech; use Sem_Mech; |
ee6ba406 | 54 | with Sem_Res; use Sem_Res; |
55 | with Sem_Util; use Sem_Util; | |
56 | with Sem_Warn; use Sem_Warn; | |
57 | with Sinfo; use Sinfo; | |
9dfe12ae | 58 | with Sinput; use Sinput; |
ee6ba406 | 59 | with Snames; use Snames; |
9dfe12ae | 60 | with Sprint; use Sprint; |
ee6ba406 | 61 | with Stand; use Stand; |
bb569db0 | 62 | with Stringt; use Stringt; |
f15731c4 | 63 | with Targparm; use Targparm; |
ee6ba406 | 64 | with Tbuild; use Tbuild; |
65 | with Ttypes; use Ttypes; | |
ee6ba406 | 66 | with Validsw; use Validsw; |
67 | ||
68 | package body Checks is | |
69 | ||
70 | -- General note: many of these routines are concerned with generating | |
71 | -- checking code to make sure that constraint error is raised at runtime. | |
72 | -- Clearly this code is only needed if the expander is active, since | |
73 | -- otherwise we will not be generating code or going into the runtime | |
74 | -- execution anyway. | |
75 | ||
76 | -- We therefore disconnect most of these checks if the expander is | |
77 | -- inactive. This has the additional benefit that we do not need to | |
78 | -- worry about the tree being messed up by previous errors (since errors | |
79 | -- turn off expansion anyway). | |
80 | ||
81 | -- There are a few exceptions to the above rule. For instance routines | |
82 | -- such as Apply_Scalar_Range_Check that do not insert any code can be | |
83 | -- safely called even when the Expander is inactive (but Errors_Detected | |
84 | -- is 0). The benefit of executing this code when expansion is off, is | |
85 | -- the ability to emit constraint error warning for static expressions | |
86 | -- even when we are not generating code. | |
87 | ||
20cf157b | 88 | -- The above is modified in gnatprove mode to ensure that proper check |
89 | -- flags are always placed, even if expansion is off. | |
90 | ||
9dfe12ae | 91 | ------------------------------------- |
92 | -- Suppression of Redundant Checks -- | |
93 | ------------------------------------- | |
94 | ||
95 | -- This unit implements a limited circuit for removal of redundant | |
96 | -- checks. The processing is based on a tracing of simple sequential | |
97 | -- flow. For any sequence of statements, we save expressions that are | |
98 | -- marked to be checked, and then if the same expression appears later | |
99 | -- with the same check, then under certain circumstances, the second | |
100 | -- check can be suppressed. | |
101 | ||
102 | -- Basically, we can suppress the check if we know for certain that | |
103 | -- the previous expression has been elaborated (together with its | |
104 | -- check), and we know that the exception frame is the same, and that | |
105 | -- nothing has happened to change the result of the exception. | |
106 | ||
107 | -- Let us examine each of these three conditions in turn to describe | |
108 | -- how we ensure that this condition is met. | |
109 | ||
110 | -- First, we need to know for certain that the previous expression has | |
6fb3c314 | 111 | -- been executed. This is done principally by the mechanism of calling |
9dfe12ae | 112 | -- Conditional_Statements_Begin at the start of any statement sequence |
113 | -- and Conditional_Statements_End at the end. The End call causes all | |
114 | -- checks remembered since the Begin call to be discarded. This does | |
115 | -- miss a few cases, notably the case of a nested BEGIN-END block with | |
116 | -- no exception handlers. But the important thing is to be conservative. | |
117 | -- The other protection is that all checks are discarded if a label | |
118 | -- is encountered, since then the assumption of sequential execution | |
119 | -- is violated, and we don't know enough about the flow. | |
120 | ||
121 | -- Second, we need to know that the exception frame is the same. We | |
122 | -- do this by killing all remembered checks when we enter a new frame. | |
123 | -- Again, that's over-conservative, but generally the cases we can help | |
124 | -- with are pretty local anyway (like the body of a loop for example). | |
125 | ||
126 | -- Third, we must be sure to forget any checks which are no longer valid. | |
127 | -- This is done by two mechanisms, first the Kill_Checks_Variable call is | |
128 | -- used to note any changes to local variables. We only attempt to deal | |
129 | -- with checks involving local variables, so we do not need to worry | |
130 | -- about global variables. Second, a call to any non-global procedure | |
131 | -- causes us to abandon all stored checks, since such a all may affect | |
132 | -- the values of any local variables. | |
133 | ||
134 | -- The following define the data structures used to deal with remembering | |
135 | -- checks so that redundant checks can be eliminated as described above. | |
136 | ||
137 | -- Right now, the only expressions that we deal with are of the form of | |
138 | -- simple local objects (either declared locally, or IN parameters) or | |
139 | -- such objects plus/minus a compile time known constant. We can do | |
140 | -- more later on if it seems worthwhile, but this catches many simple | |
141 | -- cases in practice. | |
142 | ||
143 | -- The following record type reflects a single saved check. An entry | |
144 | -- is made in the stack of saved checks if and only if the expression | |
145 | -- has been elaborated with the indicated checks. | |
146 | ||
147 | type Saved_Check is record | |
148 | Killed : Boolean; | |
149 | -- Set True if entry is killed by Kill_Checks | |
150 | ||
151 | Entity : Entity_Id; | |
152 | -- The entity involved in the expression that is checked | |
153 | ||
154 | Offset : Uint; | |
155 | -- A compile time value indicating the result of adding or | |
156 | -- subtracting a compile time value. This value is to be | |
157 | -- added to the value of the Entity. A value of zero is | |
158 | -- used for the case of a simple entity reference. | |
159 | ||
160 | Check_Type : Character; | |
161 | -- This is set to 'R' for a range check (in which case Target_Type | |
162 | -- is set to the target type for the range check) or to 'O' for an | |
163 | -- overflow check (in which case Target_Type is set to Empty). | |
164 | ||
165 | Target_Type : Entity_Id; | |
166 | -- Used only if Do_Range_Check is set. Records the target type for | |
167 | -- the check. We need this, because a check is a duplicate only if | |
6fb3c314 | 168 | -- it has the same target type (or more accurately one with a |
9dfe12ae | 169 | -- range that is smaller or equal to the stored target type of a |
170 | -- saved check). | |
171 | end record; | |
172 | ||
173 | -- The following table keeps track of saved checks. Rather than use an | |
bbbfe30c | 174 | -- extensible table, we just use a table of fixed size, and we discard |
9dfe12ae | 175 | -- any saved checks that do not fit. That's very unlikely to happen and |
176 | -- this is only an optimization in any case. | |
177 | ||
178 | Saved_Checks : array (Int range 1 .. 200) of Saved_Check; | |
179 | -- Array of saved checks | |
180 | ||
181 | Num_Saved_Checks : Nat := 0; | |
182 | -- Number of saved checks | |
183 | ||
184 | -- The following stack keeps track of statement ranges. It is treated | |
185 | -- as a stack. When Conditional_Statements_Begin is called, an entry | |
186 | -- is pushed onto this stack containing the value of Num_Saved_Checks | |
187 | -- at the time of the call. Then when Conditional_Statements_End is | |
188 | -- called, this value is popped off and used to reset Num_Saved_Checks. | |
189 | ||
190 | -- Note: again, this is a fixed length stack with a size that should | |
191 | -- always be fine. If the value of the stack pointer goes above the | |
192 | -- limit, then we just forget all saved checks. | |
193 | ||
194 | Saved_Checks_Stack : array (Int range 1 .. 100) of Nat; | |
195 | Saved_Checks_TOS : Nat := 0; | |
196 | ||
197 | ----------------------- | |
198 | -- Local Subprograms -- | |
199 | ----------------------- | |
ee6ba406 | 200 | |
0df9d43f | 201 | procedure Apply_Arithmetic_Overflow_Strict (N : Node_Id); |
3cce7f32 | 202 | -- Used to apply arithmetic overflow checks for all cases except operators |
691fe9e0 | 203 | -- on signed arithmetic types in MINIMIZED/ELIMINATED case (for which we |
0df9d43f | 204 | -- call Apply_Arithmetic_Overflow_Minimized_Eliminated below). N can be a |
205 | -- signed integer arithmetic operator (but not an if or case expression). | |
206 | -- It is also called for types other than signed integers. | |
3cce7f32 | 207 | |
208 | procedure Apply_Arithmetic_Overflow_Minimized_Eliminated (Op : Node_Id); | |
209 | -- Used to apply arithmetic overflow checks for the case where the overflow | |
0df9d43f | 210 | -- checking mode is MINIMIZED or ELIMINATED and we have a signed integer |
211 | -- arithmetic op (which includes the case of if and case expressions). Note | |
212 | -- that Do_Overflow_Check may or may not be set for node Op. In these modes | |
213 | -- we have work to do even if overflow checking is suppressed. | |
3cce7f32 | 214 | |
2fe22c69 | 215 | procedure Apply_Division_Check |
216 | (N : Node_Id; | |
217 | Rlo : Uint; | |
218 | Rhi : Uint; | |
219 | ROK : Boolean); | |
220 | -- N is an N_Op_Div, N_Op_Rem, or N_Op_Mod node. This routine applies | |
221 | -- division checks as required if the Do_Division_Check flag is set. | |
222 | -- Rlo and Rhi give the possible range of the right operand, these values | |
223 | -- can be referenced and trusted only if ROK is set True. | |
224 | ||
225 | procedure Apply_Float_Conversion_Check | |
226 | (Ck_Node : Node_Id; | |
227 | Target_Typ : Entity_Id); | |
228 | -- The checks on a conversion from a floating-point type to an integer | |
229 | -- type are delicate. They have to be performed before conversion, they | |
230 | -- have to raise an exception when the operand is a NaN, and rounding must | |
231 | -- be taken into account to determine the safe bounds of the operand. | |
232 | ||
ee6ba406 | 233 | procedure Apply_Selected_Length_Checks |
234 | (Ck_Node : Node_Id; | |
235 | Target_Typ : Entity_Id; | |
236 | Source_Typ : Entity_Id; | |
237 | Do_Static : Boolean); | |
238 | -- This is the subprogram that does all the work for Apply_Length_Check | |
239 | -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as | |
240 | -- described for the above routines. The Do_Static flag indicates that | |
241 | -- only a static check is to be done. | |
242 | ||
243 | procedure Apply_Selected_Range_Checks | |
244 | (Ck_Node : Node_Id; | |
245 | Target_Typ : Entity_Id; | |
246 | Source_Typ : Entity_Id; | |
247 | Do_Static : Boolean); | |
248 | -- This is the subprogram that does all the work for Apply_Range_Check. | |
249 | -- Expr, Target_Typ and Source_Typ are as described for the above | |
250 | -- routine. The Do_Static flag indicates that only a static check is | |
251 | -- to be done. | |
252 | ||
2af58f67 | 253 | type Check_Type is new Check_Id range Access_Check .. Division_Check; |
13dbf220 | 254 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean; |
255 | -- This function is used to see if an access or division by zero check is | |
256 | -- needed. The check is to be applied to a single variable appearing in the | |
257 | -- source, and N is the node for the reference. If N is not of this form, | |
258 | -- True is returned with no further processing. If N is of the right form, | |
259 | -- then further processing determines if the given Check is needed. | |
260 | -- | |
261 | -- The particular circuit is to see if we have the case of a check that is | |
262 | -- not needed because it appears in the right operand of a short circuited | |
263 | -- conditional where the left operand guards the check. For example: | |
264 | -- | |
265 | -- if Var = 0 or else Q / Var > 12 then | |
266 | -- ... | |
267 | -- end if; | |
268 | -- | |
269 | -- In this example, the division check is not required. At the same time | |
270 | -- we can issue warnings for suspicious use of non-short-circuited forms, | |
271 | -- such as: | |
272 | -- | |
273 | -- if Var = 0 or Q / Var > 12 then | |
274 | -- ... | |
275 | -- end if; | |
276 | ||
9dfe12ae | 277 | procedure Find_Check |
278 | (Expr : Node_Id; | |
279 | Check_Type : Character; | |
280 | Target_Type : Entity_Id; | |
281 | Entry_OK : out Boolean; | |
282 | Check_Num : out Nat; | |
283 | Ent : out Entity_Id; | |
284 | Ofs : out Uint); | |
285 | -- This routine is used by Enable_Range_Check and Enable_Overflow_Check | |
286 | -- to see if a check is of the form for optimization, and if so, to see | |
287 | -- if it has already been performed. Expr is the expression to check, | |
288 | -- and Check_Type is 'R' for a range check, 'O' for an overflow check. | |
289 | -- Target_Type is the target type for a range check, and Empty for an | |
290 | -- overflow check. If the entry is not of the form for optimization, | |
291 | -- then Entry_OK is set to False, and the remaining out parameters | |
292 | -- are undefined. If the entry is OK, then Ent/Ofs are set to the | |
293 | -- entity and offset from the expression. Check_Num is the number of | |
294 | -- a matching saved entry in Saved_Checks, or zero if no such entry | |
295 | -- is located. | |
296 | ||
ee6ba406 | 297 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id; |
298 | -- If a discriminal is used in constraining a prival, Return reference | |
299 | -- to the discriminal of the protected body (which renames the parameter | |
300 | -- of the enclosing protected operation). This clumsy transformation is | |
301 | -- needed because privals are created too late and their actual subtypes | |
302 | -- are not available when analysing the bodies of the protected operations. | |
0577b0b1 | 303 | -- This function is called whenever the bound is an entity and the scope |
304 | -- indicates a protected operation. If the bound is an in-parameter of | |
305 | -- a protected operation that is not a prival, the function returns the | |
306 | -- bound itself. | |
ee6ba406 | 307 | -- To be cleaned up??? |
308 | ||
309 | function Guard_Access | |
310 | (Cond : Node_Id; | |
311 | Loc : Source_Ptr; | |
314a23b6 | 312 | Ck_Node : Node_Id) return Node_Id; |
ee6ba406 | 313 | -- In the access type case, guard the test with a test to ensure |
314 | -- that the access value is non-null, since the checks do not | |
315 | -- not apply to null access values. | |
316 | ||
317 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr); | |
318 | -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the | |
319 | -- Constraint_Error node. | |
320 | ||
3cce7f32 | 321 | function Is_Signed_Integer_Arithmetic_Op (N : Node_Id) return Boolean; |
322 | -- Returns True if node N is for an arithmetic operation with signed | |
0326b4d4 | 323 | -- integer operands. This includes unary and binary operators, and also |
324 | -- if and case expression nodes where the dependent expressions are of | |
325 | -- a signed integer type. These are the kinds of nodes for which special | |
691fe9e0 | 326 | -- handling applies in MINIMIZED or ELIMINATED overflow checking mode. |
3cce7f32 | 327 | |
0577b0b1 | 328 | function Range_Or_Validity_Checks_Suppressed |
329 | (Expr : Node_Id) return Boolean; | |
330 | -- Returns True if either range or validity checks or both are suppressed | |
331 | -- for the type of the given expression, or, if the expression is the name | |
332 | -- of an entity, if these checks are suppressed for the entity. | |
333 | ||
ee6ba406 | 334 | function Selected_Length_Checks |
335 | (Ck_Node : Node_Id; | |
336 | Target_Typ : Entity_Id; | |
337 | Source_Typ : Entity_Id; | |
314a23b6 | 338 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 339 | -- Like Apply_Selected_Length_Checks, except it doesn't modify |
340 | -- anything, just returns a list of nodes as described in the spec of | |
341 | -- this package for the Range_Check function. | |
18cb6d78 | 342 | -- ??? In fact it does construct the test and insert it into the tree, |
343 | -- and insert actions in various ways (calling Insert_Action directly | |
344 | -- in particular) so we do not call it in GNATprove mode, contrary to | |
345 | -- Selected_Range_Checks. | |
ee6ba406 | 346 | |
347 | function Selected_Range_Checks | |
348 | (Ck_Node : Node_Id; | |
349 | Target_Typ : Entity_Id; | |
350 | Source_Typ : Entity_Id; | |
314a23b6 | 351 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 352 | -- Like Apply_Selected_Range_Checks, except it doesn't modify anything, |
353 | -- just returns a list of nodes as described in the spec of this package | |
354 | -- for the Range_Check function. | |
355 | ||
356 | ------------------------------ | |
357 | -- Access_Checks_Suppressed -- | |
358 | ------------------------------ | |
359 | ||
360 | function Access_Checks_Suppressed (E : Entity_Id) return Boolean is | |
361 | begin | |
9dfe12ae | 362 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
363 | return Is_Check_Suppressed (E, Access_Check); | |
364 | else | |
fafc6b97 | 365 | return Scope_Suppress.Suppress (Access_Check); |
9dfe12ae | 366 | end if; |
ee6ba406 | 367 | end Access_Checks_Suppressed; |
368 | ||
369 | ------------------------------------- | |
370 | -- Accessibility_Checks_Suppressed -- | |
371 | ------------------------------------- | |
372 | ||
373 | function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is | |
374 | begin | |
9dfe12ae | 375 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
376 | return Is_Check_Suppressed (E, Accessibility_Check); | |
377 | else | |
fafc6b97 | 378 | return Scope_Suppress.Suppress (Accessibility_Check); |
9dfe12ae | 379 | end if; |
ee6ba406 | 380 | end Accessibility_Checks_Suppressed; |
381 | ||
00c403ee | 382 | ----------------------------- |
383 | -- Activate_Division_Check -- | |
384 | ----------------------------- | |
385 | ||
386 | procedure Activate_Division_Check (N : Node_Id) is | |
387 | begin | |
388 | Set_Do_Division_Check (N, True); | |
389 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
390 | end Activate_Division_Check; | |
391 | ||
392 | ----------------------------- | |
393 | -- Activate_Overflow_Check -- | |
394 | ----------------------------- | |
395 | ||
396 | procedure Activate_Overflow_Check (N : Node_Id) is | |
c8e92b5f | 397 | Typ : constant Entity_Id := Etype (N); |
398 | ||
00c403ee | 399 | begin |
c8e92b5f | 400 | -- Floating-point case. If Etype is not set (this can happen when we |
401 | -- activate a check on a node that has not yet been analyzed), then | |
402 | -- we assume we do not have a floating-point type (as per our spec). | |
403 | ||
404 | if Present (Typ) and then Is_Floating_Point_Type (Typ) then | |
405 | ||
406 | -- Ignore call if we have no automatic overflow checks on the target | |
407 | -- and Check_Float_Overflow mode is not set. These are the cases in | |
408 | -- which we expect to generate infinities and NaN's with no check. | |
409 | ||
410 | if not (Machine_Overflows_On_Target or Check_Float_Overflow) then | |
411 | return; | |
412 | ||
413 | -- Ignore for unary operations ("+", "-", abs) since these can never | |
414 | -- result in overflow for floating-point cases. | |
b8446e0d | 415 | |
c8e92b5f | 416 | elsif Nkind (N) in N_Unary_Op then |
417 | return; | |
418 | ||
419 | -- Otherwise we will set the flag | |
420 | ||
421 | else | |
422 | null; | |
423 | end if; | |
424 | ||
425 | -- Discrete case | |
426 | ||
427 | else | |
428 | -- Nothing to do for Rem/Mod/Plus (overflow not possible, the check | |
429 | -- for zero-divide is a divide check, not an overflow check). | |
b8446e0d | 430 | |
c8e92b5f | 431 | if Nkind_In (N, N_Op_Rem, N_Op_Mod, N_Op_Plus) then |
432 | return; | |
433 | end if; | |
b8446e0d | 434 | end if; |
435 | ||
c8e92b5f | 436 | -- Fall through for cases where we do set the flag |
b8446e0d | 437 | |
438 | Set_Do_Overflow_Check (N, True); | |
439 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
00c403ee | 440 | end Activate_Overflow_Check; |
441 | ||
442 | -------------------------- | |
443 | -- Activate_Range_Check -- | |
444 | -------------------------- | |
445 | ||
446 | procedure Activate_Range_Check (N : Node_Id) is | |
447 | begin | |
448 | Set_Do_Range_Check (N, True); | |
449 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
450 | end Activate_Range_Check; | |
451 | ||
0577b0b1 | 452 | --------------------------------- |
453 | -- Alignment_Checks_Suppressed -- | |
454 | --------------------------------- | |
455 | ||
456 | function Alignment_Checks_Suppressed (E : Entity_Id) return Boolean is | |
457 | begin | |
458 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
459 | return Is_Check_Suppressed (E, Alignment_Check); | |
460 | else | |
fafc6b97 | 461 | return Scope_Suppress.Suppress (Alignment_Check); |
0577b0b1 | 462 | end if; |
463 | end Alignment_Checks_Suppressed; | |
464 | ||
2d70530c | 465 | ---------------------------------- |
466 | -- Allocation_Checks_Suppressed -- | |
467 | ---------------------------------- | |
468 | ||
fa771c05 | 469 | -- Note: at the current time there are no calls to this function, because |
470 | -- the relevant check is in the run-time, so it is not a check that the | |
471 | -- compiler can suppress anyway, but we still have to recognize the check | |
472 | -- name Allocation_Check since it is part of the standard. | |
473 | ||
2d70530c | 474 | function Allocation_Checks_Suppressed (E : Entity_Id) return Boolean is |
475 | begin | |
476 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
477 | return Is_Check_Suppressed (E, Allocation_Check); | |
478 | else | |
479 | return Scope_Suppress.Suppress (Allocation_Check); | |
480 | end if; | |
481 | end Allocation_Checks_Suppressed; | |
482 | ||
ee6ba406 | 483 | ------------------------- |
484 | -- Append_Range_Checks -- | |
485 | ------------------------- | |
486 | ||
487 | procedure Append_Range_Checks | |
488 | (Checks : Check_Result; | |
489 | Stmts : List_Id; | |
490 | Suppress_Typ : Entity_Id; | |
491 | Static_Sloc : Source_Ptr; | |
492 | Flag_Node : Node_Id) | |
493 | is | |
2b4f2458 | 494 | Checks_On : constant Boolean := |
495 | not Index_Checks_Suppressed (Suppress_Typ) | |
496 | or else | |
497 | not Range_Checks_Suppressed (Suppress_Typ); | |
498 | ||
9dfe12ae | 499 | Internal_Flag_Node : constant Node_Id := Flag_Node; |
500 | Internal_Static_Sloc : constant Source_Ptr := Static_Sloc; | |
501 | ||
ee6ba406 | 502 | begin |
2b4f2458 | 503 | -- For now we just return if Checks_On is false, however this should be |
504 | -- enhanced to check for an always True value in the condition and to | |
505 | -- generate a compilation warning??? | |
ee6ba406 | 506 | |
507 | if not Checks_On then | |
508 | return; | |
509 | end if; | |
510 | ||
511 | for J in 1 .. 2 loop | |
512 | exit when No (Checks (J)); | |
513 | ||
514 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
515 | and then Present (Condition (Checks (J))) | |
516 | then | |
517 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
518 | Append_To (Stmts, Checks (J)); | |
519 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
520 | end if; | |
521 | ||
522 | else | |
523 | Append_To | |
f15731c4 | 524 | (Stmts, |
525 | Make_Raise_Constraint_Error (Internal_Static_Sloc, | |
526 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 527 | end if; |
528 | end loop; | |
529 | end Append_Range_Checks; | |
530 | ||
531 | ------------------------ | |
532 | -- Apply_Access_Check -- | |
533 | ------------------------ | |
534 | ||
535 | procedure Apply_Access_Check (N : Node_Id) is | |
536 | P : constant Node_Id := Prefix (N); | |
537 | ||
538 | begin | |
13dbf220 | 539 | -- We do not need checks if we are not generating code (i.e. the |
540 | -- expander is not active). This is not just an optimization, there | |
541 | -- are cases (e.g. with pragma Debug) where generating the checks | |
542 | -- can cause real trouble). | |
284faf8b | 543 | |
a33565dd | 544 | if not Expander_Active then |
13dbf220 | 545 | return; |
9dfe12ae | 546 | end if; |
ee6ba406 | 547 | |
84d0d4a5 | 548 | -- No check if short circuiting makes check unnecessary |
9dfe12ae | 549 | |
84d0d4a5 | 550 | if not Check_Needed (P, Access_Check) then |
551 | return; | |
ee6ba406 | 552 | end if; |
9dfe12ae | 553 | |
cc60bd16 | 554 | -- No check if accessing the Offset_To_Top component of a dispatch |
555 | -- table. They are safe by construction. | |
556 | ||
040277b1 | 557 | if Tagged_Type_Expansion |
558 | and then Present (Etype (P)) | |
cc60bd16 | 559 | and then RTU_Loaded (Ada_Tags) |
560 | and then RTE_Available (RE_Offset_To_Top_Ptr) | |
561 | and then Etype (P) = RTE (RE_Offset_To_Top_Ptr) | |
562 | then | |
563 | return; | |
564 | end if; | |
565 | ||
84d0d4a5 | 566 | -- Otherwise go ahead and install the check |
9dfe12ae | 567 | |
fa7497e8 | 568 | Install_Null_Excluding_Check (P); |
ee6ba406 | 569 | end Apply_Access_Check; |
570 | ||
571 | ------------------------------- | |
572 | -- Apply_Accessibility_Check -- | |
573 | ------------------------------- | |
574 | ||
55dc6dc2 | 575 | procedure Apply_Accessibility_Check |
576 | (N : Node_Id; | |
577 | Typ : Entity_Id; | |
578 | Insert_Node : Node_Id) | |
579 | is | |
ee6ba406 | 580 | Loc : constant Source_Ptr := Sloc (N); |
1a9cc6cd | 581 | Param_Ent : Entity_Id := Param_Entity (N); |
ee6ba406 | 582 | Param_Level : Node_Id; |
583 | Type_Level : Node_Id; | |
584 | ||
585 | begin | |
47d210a3 | 586 | if Ada_Version >= Ada_2012 |
587 | and then not Present (Param_Ent) | |
588 | and then Is_Entity_Name (N) | |
589 | and then Ekind_In (Entity (N), E_Constant, E_Variable) | |
590 | and then Present (Effective_Extra_Accessibility (Entity (N))) | |
591 | then | |
592 | Param_Ent := Entity (N); | |
593 | while Present (Renamed_Object (Param_Ent)) loop | |
1a9cc6cd | 594 | |
47d210a3 | 595 | -- Renamed_Object must return an Entity_Name here |
596 | -- because of preceding "Present (E_E_A (...))" test. | |
597 | ||
598 | Param_Ent := Entity (Renamed_Object (Param_Ent)); | |
599 | end loop; | |
600 | end if; | |
601 | ||
ee6ba406 | 602 | if Inside_A_Generic then |
603 | return; | |
604 | ||
6ffc64fc | 605 | -- Only apply the run-time check if the access parameter has an |
606 | -- associated extra access level parameter and when the level of the | |
607 | -- type is less deep than the level of the access parameter, and | |
608 | -- accessibility checks are not suppressed. | |
ee6ba406 | 609 | |
610 | elsif Present (Param_Ent) | |
611 | and then Present (Extra_Accessibility (Param_Ent)) | |
47d210a3 | 612 | and then UI_Gt (Object_Access_Level (N), |
1a9cc6cd | 613 | Deepest_Type_Access_Level (Typ)) |
ee6ba406 | 614 | and then not Accessibility_Checks_Suppressed (Param_Ent) |
615 | and then not Accessibility_Checks_Suppressed (Typ) | |
616 | then | |
617 | Param_Level := | |
618 | New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc); | |
619 | ||
1a9cc6cd | 620 | Type_Level := |
621 | Make_Integer_Literal (Loc, Deepest_Type_Access_Level (Typ)); | |
ee6ba406 | 622 | |
bf3e1520 | 623 | -- Raise Program_Error if the accessibility level of the access |
84d0d4a5 | 624 | -- parameter is deeper than the level of the target access type. |
ee6ba406 | 625 | |
55dc6dc2 | 626 | Insert_Action (Insert_Node, |
ee6ba406 | 627 | Make_Raise_Program_Error (Loc, |
628 | Condition => | |
629 | Make_Op_Gt (Loc, | |
630 | Left_Opnd => Param_Level, | |
f15731c4 | 631 | Right_Opnd => Type_Level), |
632 | Reason => PE_Accessibility_Check_Failed)); | |
ee6ba406 | 633 | |
634 | Analyze_And_Resolve (N); | |
635 | end if; | |
636 | end Apply_Accessibility_Check; | |
637 | ||
0577b0b1 | 638 | -------------------------------- |
639 | -- Apply_Address_Clause_Check -- | |
640 | -------------------------------- | |
641 | ||
642 | procedure Apply_Address_Clause_Check (E : Entity_Id; N : Node_Id) is | |
d950dc79 | 643 | pragma Assert (Nkind (N) = N_Freeze_Entity); |
644 | ||
8650387e | 645 | AC : constant Node_Id := Address_Clause (E); |
646 | Loc : constant Source_Ptr := Sloc (AC); | |
647 | Typ : constant Entity_Id := Etype (E); | |
c2b56224 | 648 | |
c2b56224 | 649 | Expr : Node_Id; |
0577b0b1 | 650 | -- Address expression (not necessarily the same as Aexp, for example |
651 | -- when Aexp is a reference to a constant, in which case Expr gets | |
7b8fa048 | 652 | -- reset to reference the value expression of the constant). |
0577b0b1 | 653 | |
c2b56224 | 654 | begin |
d6da7448 | 655 | -- See if alignment check needed. Note that we never need a check if the |
656 | -- maximum alignment is one, since the check will always succeed. | |
657 | ||
658 | -- Note: we do not check for checks suppressed here, since that check | |
659 | -- was done in Sem_Ch13 when the address clause was processed. We are | |
660 | -- only called if checks were not suppressed. The reason for this is | |
661 | -- that we have to delay the call to Apply_Alignment_Check till freeze | |
662 | -- time (so that all types etc are elaborated), but we have to check | |
663 | -- the status of check suppressing at the point of the address clause. | |
664 | ||
665 | if No (AC) | |
666 | or else not Check_Address_Alignment (AC) | |
667 | or else Maximum_Alignment = 1 | |
668 | then | |
669 | return; | |
670 | end if; | |
671 | ||
672 | -- Obtain expression from address clause | |
9dfe12ae | 673 | |
514a5555 | 674 | Expr := Address_Value (Expression (AC)); |
0577b0b1 | 675 | |
514a5555 | 676 | -- See if we know that Expr has an acceptable value at compile time. If |
677 | -- it hasn't or we don't know, we defer issuing the warning until the | |
678 | -- end of the compilation to take into account back end annotations. | |
c2b56224 | 679 | |
680 | if Compile_Time_Known_Value (Expr) | |
f2a06be9 | 681 | and then (Known_Alignment (E) or else Known_Alignment (Typ)) |
c2b56224 | 682 | then |
f2a06be9 | 683 | declare |
684 | AL : Uint := Alignment (Typ); | |
685 | ||
686 | begin | |
8650387e | 687 | -- The object alignment might be more restrictive than the type |
688 | -- alignment. | |
f2a06be9 | 689 | |
690 | if Known_Alignment (E) then | |
691 | AL := Alignment (E); | |
692 | end if; | |
693 | ||
514a5555 | 694 | if Expr_Value (Expr) mod AL = 0 then |
0577b0b1 | 695 | return; |
f2a06be9 | 696 | end if; |
697 | end; | |
c2b56224 | 698 | |
7161e166 | 699 | -- If the expression has the form X'Address, then we can find out if the |
700 | -- object X has an alignment that is compatible with the object E. If it | |
701 | -- hasn't or we don't know, we defer issuing the warning until the end | |
702 | -- of the compilation to take into account back end annotations. | |
c2b56224 | 703 | |
0577b0b1 | 704 | elsif Nkind (Expr) = N_Attribute_Reference |
705 | and then Attribute_Name (Expr) = Name_Address | |
7161e166 | 706 | and then |
707 | Has_Compatible_Alignment (E, Prefix (Expr), False) = Known_Compatible | |
0577b0b1 | 708 | then |
d6da7448 | 709 | return; |
0577b0b1 | 710 | end if; |
c2b56224 | 711 | |
6fb3c314 | 712 | -- Here we do not know if the value is acceptable. Strictly we don't |
713 | -- have to do anything, since if the alignment is bad, we have an | |
714 | -- erroneous program. However we are allowed to check for erroneous | |
715 | -- conditions and we decide to do this by default if the check is not | |
716 | -- suppressed. | |
0577b0b1 | 717 | |
718 | -- However, don't do the check if elaboration code is unwanted | |
719 | ||
720 | if Restriction_Active (No_Elaboration_Code) then | |
721 | return; | |
722 | ||
723 | -- Generate a check to raise PE if alignment may be inappropriate | |
724 | ||
725 | else | |
1916d94e | 726 | -- If the original expression is a nonstatic constant, use the name |
8650387e | 727 | -- of the constant itself rather than duplicating its initialization |
728 | -- expression, which was extracted above. | |
0577b0b1 | 729 | |
00c403ee | 730 | -- Note: Expr is empty if the address-clause is applied to in-mode |
731 | -- actuals (allowed by 13.1(22)). | |
732 | ||
733 | if not Present (Expr) | |
734 | or else | |
735 | (Is_Entity_Name (Expression (AC)) | |
736 | and then Ekind (Entity (Expression (AC))) = E_Constant | |
8650387e | 737 | and then Nkind (Parent (Entity (Expression (AC)))) = |
738 | N_Object_Declaration) | |
0577b0b1 | 739 | then |
740 | Expr := New_Copy_Tree (Expression (AC)); | |
741 | else | |
742 | Remove_Side_Effects (Expr); | |
c2b56224 | 743 | end if; |
c2b56224 | 744 | |
d950dc79 | 745 | if No (Actions (N)) then |
746 | Set_Actions (N, New_List); | |
747 | end if; | |
748 | ||
749 | Prepend_To (Actions (N), | |
0577b0b1 | 750 | Make_Raise_Program_Error (Loc, |
751 | Condition => | |
752 | Make_Op_Ne (Loc, | |
8650387e | 753 | Left_Opnd => |
0577b0b1 | 754 | Make_Op_Mod (Loc, |
8650387e | 755 | Left_Opnd => |
0577b0b1 | 756 | Unchecked_Convert_To |
757 | (RTE (RE_Integer_Address), Expr), | |
758 | Right_Opnd => | |
759 | Make_Attribute_Reference (Loc, | |
d950dc79 | 760 | Prefix => New_Occurrence_Of (E, Loc), |
0577b0b1 | 761 | Attribute_Name => Name_Alignment)), |
762 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
8650387e | 763 | Reason => PE_Misaligned_Address_Value)); |
7b8fa048 | 764 | |
765 | Warning_Msg := No_Error_Msg; | |
d950dc79 | 766 | Analyze (First (Actions (N)), Suppress => All_Checks); |
cd309f05 | 767 | |
514a5555 | 768 | -- If the above raise action generated a warning message (for example |
7b8fa048 | 769 | -- from Warn_On_Non_Local_Exception mode with the active restriction |
770 | -- No_Exception_Propagation). | |
771 | ||
772 | if Warning_Msg /= No_Error_Msg then | |
8650387e | 773 | |
7b8fa048 | 774 | -- If the expression has a known at compile time value, then |
775 | -- once we know the alignment of the type, we can check if the | |
776 | -- exception will be raised or not, and if not, we don't need | |
777 | -- the warning so we will kill the warning later on. | |
778 | ||
779 | if Compile_Time_Known_Value (Expr) then | |
780 | Alignment_Warnings.Append | |
781 | ((E => E, A => Expr_Value (Expr), W => Warning_Msg)); | |
cd309f05 | 782 | |
8650387e | 783 | -- Add explanation of the warning generated by the check |
784 | ||
785 | else | |
514a5555 | 786 | Error_Msg_N |
8650387e | 787 | ("\address value may be incompatible with alignment of " |
788 | & "object?X?", AC); | |
514a5555 | 789 | end if; |
cd309f05 | 790 | end if; |
78be29d1 | 791 | |
0577b0b1 | 792 | return; |
793 | end if; | |
9dfe12ae | 794 | |
795 | exception | |
8650387e | 796 | |
0577b0b1 | 797 | -- If we have some missing run time component in configurable run time |
798 | -- mode then just skip the check (it is not required in any case). | |
799 | ||
9dfe12ae | 800 | when RE_Not_Available => |
801 | return; | |
0577b0b1 | 802 | end Apply_Address_Clause_Check; |
c2b56224 | 803 | |
ee6ba406 | 804 | ------------------------------------- |
805 | -- Apply_Arithmetic_Overflow_Check -- | |
806 | ------------------------------------- | |
807 | ||
3cce7f32 | 808 | procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is |
809 | begin | |
810 | -- Use old routine in almost all cases (the only case we are treating | |
21a55437 | 811 | -- specially is the case of a signed integer arithmetic op with the |
0df9d43f | 812 | -- overflow checking mode set to MINIMIZED or ELIMINATED). |
3cce7f32 | 813 | |
0df9d43f | 814 | if Overflow_Check_Mode = Strict |
3cce7f32 | 815 | or else not Is_Signed_Integer_Arithmetic_Op (N) |
816 | then | |
0df9d43f | 817 | Apply_Arithmetic_Overflow_Strict (N); |
3cce7f32 | 818 | |
21a55437 | 819 | -- Otherwise use the new routine for the case of a signed integer |
820 | -- arithmetic op, with Do_Overflow_Check set to True, and the checking | |
821 | -- mode is MINIMIZED or ELIMINATED. | |
3cce7f32 | 822 | |
823 | else | |
824 | Apply_Arithmetic_Overflow_Minimized_Eliminated (N); | |
825 | end if; | |
826 | end Apply_Arithmetic_Overflow_Check; | |
827 | ||
0df9d43f | 828 | -------------------------------------- |
829 | -- Apply_Arithmetic_Overflow_Strict -- | |
830 | -------------------------------------- | |
3cce7f32 | 831 | |
fc1dbe36 | 832 | -- This routine is called only if the type is an integer type and an |
833 | -- arithmetic overflow check may be needed for op (add, subtract, or | |
834 | -- multiply). This check is performed if Backend_Overflow_Checks_On_Target | |
835 | -- is not enabled and Do_Overflow_Check is set. In this case we expand the | |
f40f9731 | 836 | -- operation into a more complex sequence of tests that ensures that |
837 | -- overflow is properly caught. | |
ee6ba406 | 838 | |
0df9d43f | 839 | -- This is used in CHECKED modes. It is identical to the code for this |
840 | -- cases before the big overflow earthquake, thus ensuring that in this | |
841 | -- modes we have compatible behavior (and reliability) to what was there | |
842 | -- before. It is also called for types other than signed integers, and if | |
843 | -- the Do_Overflow_Check flag is off. | |
3cce7f32 | 844 | |
845 | -- Note: we also call this routine if we decide in the MINIMIZED case | |
846 | -- to give up and just generate an overflow check without any fuss. | |
847 | ||
0df9d43f | 848 | procedure Apply_Arithmetic_Overflow_Strict (N : Node_Id) is |
21a55437 | 849 | Loc : constant Source_Ptr := Sloc (N); |
850 | Typ : constant Entity_Id := Etype (N); | |
851 | Rtyp : constant Entity_Id := Root_Type (Typ); | |
ee6ba406 | 852 | |
853 | begin | |
0df9d43f | 854 | -- Nothing to do if Do_Overflow_Check not set or overflow checks |
855 | -- suppressed. | |
856 | ||
857 | if not Do_Overflow_Check (N) then | |
858 | return; | |
859 | end if; | |
860 | ||
f40f9731 | 861 | -- An interesting special case. If the arithmetic operation appears as |
862 | -- the operand of a type conversion: | |
863 | ||
864 | -- type1 (x op y) | |
865 | ||
866 | -- and all the following conditions apply: | |
867 | ||
868 | -- arithmetic operation is for a signed integer type | |
869 | -- target type type1 is a static integer subtype | |
870 | -- range of x and y are both included in the range of type1 | |
871 | -- range of x op y is included in the range of type1 | |
872 | -- size of type1 is at least twice the result size of op | |
873 | ||
a36d34e4 | 874 | -- then we don't do an overflow check in any case. Instead, we transform |
f40f9731 | 875 | -- the operation so that we end up with: |
876 | ||
877 | -- type1 (type1 (x) op type1 (y)) | |
878 | ||
879 | -- This avoids intermediate overflow before the conversion. It is | |
880 | -- explicitly permitted by RM 3.5.4(24): | |
881 | ||
882 | -- For the execution of a predefined operation of a signed integer | |
883 | -- type, the implementation need not raise Constraint_Error if the | |
884 | -- result is outside the base range of the type, so long as the | |
885 | -- correct result is produced. | |
886 | ||
887 | -- It's hard to imagine that any programmer counts on the exception | |
888 | -- being raised in this case, and in any case it's wrong coding to | |
889 | -- have this expectation, given the RM permission. Furthermore, other | |
890 | -- Ada compilers do allow such out of range results. | |
891 | ||
892 | -- Note that we do this transformation even if overflow checking is | |
893 | -- off, since this is precisely about giving the "right" result and | |
894 | -- avoiding the need for an overflow check. | |
895 | ||
8eb4a5eb | 896 | -- Note: this circuit is partially redundant with respect to the similar |
897 | -- processing in Exp_Ch4.Expand_N_Type_Conversion, but the latter deals | |
898 | -- with cases that do not come through here. We still need the following | |
899 | -- processing even with the Exp_Ch4 code in place, since we want to be | |
900 | -- sure not to generate the arithmetic overflow check in these cases | |
901 | -- (Exp_Ch4 would have a hard time removing them once generated). | |
902 | ||
f40f9731 | 903 | if Is_Signed_Integer_Type (Typ) |
904 | and then Nkind (Parent (N)) = N_Type_Conversion | |
ee6ba406 | 905 | then |
f32c377d | 906 | Conversion_Optimization : declare |
f40f9731 | 907 | Target_Type : constant Entity_Id := |
b6341c67 | 908 | Base_Type (Entity (Subtype_Mark (Parent (N)))); |
f40f9731 | 909 | |
910 | Llo, Lhi : Uint; | |
911 | Rlo, Rhi : Uint; | |
912 | LOK, ROK : Boolean; | |
913 | ||
914 | Vlo : Uint; | |
915 | Vhi : Uint; | |
916 | VOK : Boolean; | |
917 | ||
918 | Tlo : Uint; | |
919 | Thi : Uint; | |
920 | ||
921 | begin | |
922 | if Is_Integer_Type (Target_Type) | |
923 | and then RM_Size (Root_Type (Target_Type)) >= 2 * RM_Size (Rtyp) | |
924 | then | |
925 | Tlo := Expr_Value (Type_Low_Bound (Target_Type)); | |
926 | Thi := Expr_Value (Type_High_Bound (Target_Type)); | |
927 | ||
9c486805 | 928 | Determine_Range |
929 | (Left_Opnd (N), LOK, Llo, Lhi, Assume_Valid => True); | |
930 | Determine_Range | |
931 | (Right_Opnd (N), ROK, Rlo, Rhi, Assume_Valid => True); | |
f40f9731 | 932 | |
933 | if (LOK and ROK) | |
934 | and then Tlo <= Llo and then Lhi <= Thi | |
935 | and then Tlo <= Rlo and then Rhi <= Thi | |
936 | then | |
9c486805 | 937 | Determine_Range (N, VOK, Vlo, Vhi, Assume_Valid => True); |
f40f9731 | 938 | |
939 | if VOK and then Tlo <= Vlo and then Vhi <= Thi then | |
940 | Rewrite (Left_Opnd (N), | |
941 | Make_Type_Conversion (Loc, | |
942 | Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), | |
943 | Expression => Relocate_Node (Left_Opnd (N)))); | |
944 | ||
945 | Rewrite (Right_Opnd (N), | |
946 | Make_Type_Conversion (Loc, | |
947 | Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), | |
948 | Expression => Relocate_Node (Right_Opnd (N)))); | |
949 | ||
780bfb21 | 950 | -- Rewrite the conversion operand so that the original |
951 | -- node is retained, in order to avoid the warning for | |
952 | -- redundant conversions in Resolve_Type_Conversion. | |
953 | ||
954 | Rewrite (N, Relocate_Node (N)); | |
955 | ||
f40f9731 | 956 | Set_Etype (N, Target_Type); |
780bfb21 | 957 | |
f40f9731 | 958 | Analyze_And_Resolve (Left_Opnd (N), Target_Type); |
959 | Analyze_And_Resolve (Right_Opnd (N), Target_Type); | |
960 | ||
961 | -- Given that the target type is twice the size of the | |
962 | -- source type, overflow is now impossible, so we can | |
963 | -- safely kill the overflow check and return. | |
964 | ||
965 | Set_Do_Overflow_Check (N, False); | |
966 | return; | |
967 | end if; | |
968 | end if; | |
969 | end if; | |
f32c377d | 970 | end Conversion_Optimization; |
ee6ba406 | 971 | end if; |
972 | ||
f40f9731 | 973 | -- Now see if an overflow check is required |
974 | ||
975 | declare | |
976 | Siz : constant Int := UI_To_Int (Esize (Rtyp)); | |
977 | Dsiz : constant Int := Siz * 2; | |
978 | Opnod : Node_Id; | |
979 | Ctyp : Entity_Id; | |
980 | Opnd : Node_Id; | |
981 | Cent : RE_Id; | |
ee6ba406 | 982 | |
f40f9731 | 983 | begin |
984 | -- Skip check if back end does overflow checks, or the overflow flag | |
df40eeb0 | 985 | -- is not set anyway, or we are not doing code expansion, or the |
986 | -- parent node is a type conversion whose operand is an arithmetic | |
987 | -- operation on signed integers on which the expander can promote | |
bbbed24b | 988 | -- later the operands to type Integer (see Expand_N_Type_Conversion). |
ee6ba406 | 989 | |
f40f9731 | 990 | if Backend_Overflow_Checks_On_Target |
991 | or else not Do_Overflow_Check (N) | |
a33565dd | 992 | or else not Expander_Active |
df40eeb0 | 993 | or else (Present (Parent (N)) |
994 | and then Nkind (Parent (N)) = N_Type_Conversion | |
995 | and then Integer_Promotion_Possible (Parent (N))) | |
f40f9731 | 996 | then |
997 | return; | |
998 | end if; | |
ee6ba406 | 999 | |
f40f9731 | 1000 | -- Otherwise, generate the full general code for front end overflow |
1001 | -- detection, which works by doing arithmetic in a larger type: | |
ee6ba406 | 1002 | |
f40f9731 | 1003 | -- x op y |
ee6ba406 | 1004 | |
f40f9731 | 1005 | -- is expanded into |
ee6ba406 | 1006 | |
f40f9731 | 1007 | -- Typ (Checktyp (x) op Checktyp (y)); |
ee6ba406 | 1008 | |
f40f9731 | 1009 | -- where Typ is the type of the original expression, and Checktyp is |
1010 | -- an integer type of sufficient length to hold the largest possible | |
1011 | -- result. | |
ee6ba406 | 1012 | |
f40f9731 | 1013 | -- If the size of check type exceeds the size of Long_Long_Integer, |
1014 | -- we use a different approach, expanding to: | |
ee6ba406 | 1015 | |
f40f9731 | 1016 | -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y))) |
ee6ba406 | 1017 | |
f40f9731 | 1018 | -- where xxx is Add, Multiply or Subtract as appropriate |
ee6ba406 | 1019 | |
f40f9731 | 1020 | -- Find check type if one exists |
1021 | ||
1022 | if Dsiz <= Standard_Integer_Size then | |
1023 | Ctyp := Standard_Integer; | |
ee6ba406 | 1024 | |
f40f9731 | 1025 | elsif Dsiz <= Standard_Long_Long_Integer_Size then |
1026 | Ctyp := Standard_Long_Long_Integer; | |
1027 | ||
c9f84db7 | 1028 | -- No check type exists, use runtime call |
ee6ba406 | 1029 | |
1030 | else | |
f40f9731 | 1031 | if Nkind (N) = N_Op_Add then |
1032 | Cent := RE_Add_With_Ovflo_Check; | |
ee6ba406 | 1033 | |
f40f9731 | 1034 | elsif Nkind (N) = N_Op_Multiply then |
1035 | Cent := RE_Multiply_With_Ovflo_Check; | |
ee6ba406 | 1036 | |
f40f9731 | 1037 | else |
1038 | pragma Assert (Nkind (N) = N_Op_Subtract); | |
1039 | Cent := RE_Subtract_With_Ovflo_Check; | |
1040 | end if; | |
1041 | ||
1042 | Rewrite (N, | |
1043 | OK_Convert_To (Typ, | |
1044 | Make_Function_Call (Loc, | |
83c6c069 | 1045 | Name => New_Occurrence_Of (RTE (Cent), Loc), |
f40f9731 | 1046 | Parameter_Associations => New_List ( |
1047 | OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)), | |
1048 | OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N)))))); | |
ee6ba406 | 1049 | |
f40f9731 | 1050 | Analyze_And_Resolve (N, Typ); |
1051 | return; | |
1052 | end if; | |
ee6ba406 | 1053 | |
f40f9731 | 1054 | -- If we fall through, we have the case where we do the arithmetic |
1055 | -- in the next higher type and get the check by conversion. In these | |
1056 | -- cases Ctyp is set to the type to be used as the check type. | |
ee6ba406 | 1057 | |
f40f9731 | 1058 | Opnod := Relocate_Node (N); |
ee6ba406 | 1059 | |
f40f9731 | 1060 | Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod)); |
ee6ba406 | 1061 | |
f40f9731 | 1062 | Analyze (Opnd); |
1063 | Set_Etype (Opnd, Ctyp); | |
1064 | Set_Analyzed (Opnd, True); | |
1065 | Set_Left_Opnd (Opnod, Opnd); | |
ee6ba406 | 1066 | |
f40f9731 | 1067 | Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod)); |
ee6ba406 | 1068 | |
f40f9731 | 1069 | Analyze (Opnd); |
1070 | Set_Etype (Opnd, Ctyp); | |
1071 | Set_Analyzed (Opnd, True); | |
1072 | Set_Right_Opnd (Opnod, Opnd); | |
ee6ba406 | 1073 | |
f40f9731 | 1074 | -- The type of the operation changes to the base type of the check |
1075 | -- type, and we reset the overflow check indication, since clearly no | |
1076 | -- overflow is possible now that we are using a double length type. | |
1077 | -- We also set the Analyzed flag to avoid a recursive attempt to | |
1078 | -- expand the node. | |
ee6ba406 | 1079 | |
f40f9731 | 1080 | Set_Etype (Opnod, Base_Type (Ctyp)); |
1081 | Set_Do_Overflow_Check (Opnod, False); | |
1082 | Set_Analyzed (Opnod, True); | |
ee6ba406 | 1083 | |
f40f9731 | 1084 | -- Now build the outer conversion |
ee6ba406 | 1085 | |
f40f9731 | 1086 | Opnd := OK_Convert_To (Typ, Opnod); |
1087 | Analyze (Opnd); | |
1088 | Set_Etype (Opnd, Typ); | |
9dfe12ae | 1089 | |
f40f9731 | 1090 | -- In the discrete type case, we directly generate the range check |
1091 | -- for the outer operand. This range check will implement the | |
1092 | -- required overflow check. | |
9dfe12ae | 1093 | |
f40f9731 | 1094 | if Is_Discrete_Type (Typ) then |
1095 | Rewrite (N, Opnd); | |
1096 | Generate_Range_Check | |
1097 | (Expression (N), Typ, CE_Overflow_Check_Failed); | |
9dfe12ae | 1098 | |
f40f9731 | 1099 | -- For other types, we enable overflow checking on the conversion, |
1100 | -- after setting the node as analyzed to prevent recursive attempts | |
1101 | -- to expand the conversion node. | |
9dfe12ae | 1102 | |
f40f9731 | 1103 | else |
1104 | Set_Analyzed (Opnd, True); | |
1105 | Enable_Overflow_Check (Opnd); | |
1106 | Rewrite (N, Opnd); | |
1107 | end if; | |
1108 | ||
1109 | exception | |
1110 | when RE_Not_Available => | |
1111 | return; | |
1112 | end; | |
0df9d43f | 1113 | end Apply_Arithmetic_Overflow_Strict; |
3cce7f32 | 1114 | |
1115 | ---------------------------------------------------- | |
1116 | -- Apply_Arithmetic_Overflow_Minimized_Eliminated -- | |
1117 | ---------------------------------------------------- | |
1118 | ||
1119 | procedure Apply_Arithmetic_Overflow_Minimized_Eliminated (Op : Node_Id) is | |
1120 | pragma Assert (Is_Signed_Integer_Arithmetic_Op (Op)); | |
3cce7f32 | 1121 | |
1122 | Loc : constant Source_Ptr := Sloc (Op); | |
1123 | P : constant Node_Id := Parent (Op); | |
1124 | ||
49b3a812 | 1125 | LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); |
1126 | -- Operands and results are of this type when we convert | |
1127 | ||
3cce7f32 | 1128 | Result_Type : constant Entity_Id := Etype (Op); |
1129 | -- Original result type | |
1130 | ||
db415383 | 1131 | Check_Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
3cce7f32 | 1132 | pragma Assert (Check_Mode in Minimized_Or_Eliminated); |
1133 | ||
1134 | Lo, Hi : Uint; | |
1135 | -- Ranges of values for result | |
1136 | ||
1137 | begin | |
1138 | -- Nothing to do if our parent is one of the following: | |
1139 | ||
0326b4d4 | 1140 | -- Another signed integer arithmetic op |
3cce7f32 | 1141 | -- A membership operation |
1142 | -- A comparison operation | |
1143 | ||
1144 | -- In all these cases, we will process at the higher level (and then | |
1145 | -- this node will be processed during the downwards recursion that | |
0df9d43f | 1146 | -- is part of the processing in Minimize_Eliminate_Overflows). |
3cce7f32 | 1147 | |
1148 | if Is_Signed_Integer_Arithmetic_Op (P) | |
b8a17a21 | 1149 | or else Nkind (P) in N_Membership_Test |
1150 | or else Nkind (P) in N_Op_Compare | |
aa4b16cb | 1151 | |
70a2dff4 | 1152 | -- This is also true for an alternative in a case expression |
1153 | ||
1154 | or else Nkind (P) = N_Case_Expression_Alternative | |
1155 | ||
1156 | -- This is also true for a range operand in a membership test | |
aa4b16cb | 1157 | |
b8a17a21 | 1158 | or else (Nkind (P) = N_Range |
1159 | and then Nkind (Parent (P)) in N_Membership_Test) | |
3cce7f32 | 1160 | then |
af90720d | 1161 | -- If_Expressions and Case_Expressions are treated as arithmetic |
1162 | -- ops, but if they appear in an assignment or similar contexts | |
1163 | -- there is no overflow check that starts from that parent node, | |
1164 | -- so apply check now. | |
1165 | ||
1166 | if Nkind_In (P, N_If_Expression, N_Case_Expression) | |
1167 | and then not Is_Signed_Integer_Arithmetic_Op (Parent (P)) | |
1168 | then | |
1169 | null; | |
1170 | else | |
1171 | return; | |
1172 | end if; | |
3cce7f32 | 1173 | end if; |
1174 | ||
0326b4d4 | 1175 | -- Otherwise, we have a top level arithmetic operation node, and this |
21a55437 | 1176 | -- is where we commence the special processing for MINIMIZED/ELIMINATED |
1177 | -- modes. This is the case where we tell the machinery not to move into | |
1178 | -- Bignum mode at this top level (of course the top level operation | |
1179 | -- will still be in Bignum mode if either of its operands are of type | |
1180 | -- Bignum). | |
3cce7f32 | 1181 | |
0df9d43f | 1182 | Minimize_Eliminate_Overflows (Op, Lo, Hi, Top_Level => True); |
3cce7f32 | 1183 | |
1184 | -- That call may but does not necessarily change the result type of Op. | |
1185 | -- It is the job of this routine to undo such changes, so that at the | |
1186 | -- top level, we have the proper type. This "undoing" is a point at | |
1187 | -- which a final overflow check may be applied. | |
1188 | ||
f32c377d | 1189 | -- If the result type was not fiddled we are all set. We go to base |
1190 | -- types here because things may have been rewritten to generate the | |
1191 | -- base type of the operand types. | |
3cce7f32 | 1192 | |
f32c377d | 1193 | if Base_Type (Etype (Op)) = Base_Type (Result_Type) then |
3cce7f32 | 1194 | return; |
1195 | ||
1196 | -- Bignum case | |
1197 | ||
49b3a812 | 1198 | elsif Is_RTE (Etype (Op), RE_Bignum) then |
3cce7f32 | 1199 | |
d94b5da2 | 1200 | -- We need a sequence that looks like: |
3cce7f32 | 1201 | |
1202 | -- Rnn : Result_Type; | |
1203 | ||
1204 | -- declare | |
d94b5da2 | 1205 | -- M : Mark_Id := SS_Mark; |
3cce7f32 | 1206 | -- begin |
49b3a812 | 1207 | -- Rnn := Long_Long_Integer'Base (From_Bignum (Op)); |
3cce7f32 | 1208 | -- SS_Release (M); |
1209 | -- end; | |
1210 | ||
1211 | -- This block is inserted (using Insert_Actions), and then the node | |
1212 | -- is replaced with a reference to Rnn. | |
1213 | ||
75b45a21 | 1214 | -- If our parent is a conversion node then there is no point in |
a36d34e4 | 1215 | -- generating a conversion to Result_Type. Instead, we let the parent |
75b45a21 | 1216 | -- handle this. Note that this special case is not just about |
1217 | -- optimization. Consider | |
3cce7f32 | 1218 | |
1219 | -- A,B,C : Integer; | |
1220 | -- ... | |
49b3a812 | 1221 | -- X := Long_Long_Integer'Base (A * (B ** C)); |
3cce7f32 | 1222 | |
1223 | -- Now the product may fit in Long_Long_Integer but not in Integer. | |
21a55437 | 1224 | -- In MINIMIZED/ELIMINATED mode, we don't want to introduce an |
1225 | -- overflow exception for this intermediate value. | |
3cce7f32 | 1226 | |
1227 | declare | |
49b3a812 | 1228 | Blk : constant Node_Id := Make_Bignum_Block (Loc); |
3cce7f32 | 1229 | Rnn : constant Entity_Id := Make_Temporary (Loc, 'R', Op); |
1230 | RHS : Node_Id; | |
1231 | ||
1232 | Rtype : Entity_Id; | |
1233 | ||
1234 | begin | |
1235 | RHS := Convert_From_Bignum (Op); | |
1236 | ||
1237 | if Nkind (P) /= N_Type_Conversion then | |
49b3a812 | 1238 | Convert_To_And_Rewrite (Result_Type, RHS); |
3cce7f32 | 1239 | Rtype := Result_Type; |
1240 | ||
1241 | -- Interesting question, do we need a check on that conversion | |
1242 | -- operation. Answer, not if we know the result is in range. | |
1243 | -- At the moment we are not taking advantage of this. To be | |
1244 | -- looked at later ??? | |
1245 | ||
1246 | else | |
49b3a812 | 1247 | Rtype := LLIB; |
3cce7f32 | 1248 | end if; |
1249 | ||
1250 | Insert_Before | |
1251 | (First (Statements (Handled_Statement_Sequence (Blk))), | |
1252 | Make_Assignment_Statement (Loc, | |
1253 | Name => New_Occurrence_Of (Rnn, Loc), | |
1254 | Expression => RHS)); | |
1255 | ||
1256 | Insert_Actions (Op, New_List ( | |
1257 | Make_Object_Declaration (Loc, | |
1258 | Defining_Identifier => Rnn, | |
1259 | Object_Definition => New_Occurrence_Of (Rtype, Loc)), | |
1260 | Blk)); | |
1261 | ||
1262 | Rewrite (Op, New_Occurrence_Of (Rnn, Loc)); | |
1263 | Analyze_And_Resolve (Op); | |
1264 | end; | |
1265 | ||
af90720d | 1266 | -- Here we know the result is Long_Long_Integer'Base, or that it has |
412f75eb | 1267 | -- been rewritten because the parent operation is a conversion. See |
0df9d43f | 1268 | -- Apply_Arithmetic_Overflow_Strict.Conversion_Optimization. |
3cce7f32 | 1269 | |
1270 | else | |
f32c377d | 1271 | pragma Assert |
1272 | (Etype (Op) = LLIB or else Nkind (Parent (Op)) = N_Type_Conversion); | |
3cce7f32 | 1273 | |
1274 | -- All we need to do here is to convert the result to the proper | |
1275 | -- result type. As explained above for the Bignum case, we can | |
1276 | -- omit this if our parent is a type conversion. | |
1277 | ||
1278 | if Nkind (P) /= N_Type_Conversion then | |
1279 | Convert_To_And_Rewrite (Result_Type, Op); | |
1280 | end if; | |
1281 | ||
1282 | Analyze_And_Resolve (Op); | |
1283 | end if; | |
1284 | end Apply_Arithmetic_Overflow_Minimized_Eliminated; | |
ee6ba406 | 1285 | |
ee6ba406 | 1286 | ---------------------------- |
1287 | -- Apply_Constraint_Check -- | |
1288 | ---------------------------- | |
1289 | ||
1290 | procedure Apply_Constraint_Check | |
1291 | (N : Node_Id; | |
1292 | Typ : Entity_Id; | |
1293 | No_Sliding : Boolean := False) | |
1294 | is | |
1295 | Desig_Typ : Entity_Id; | |
1296 | ||
1297 | begin | |
7aafae1c | 1298 | -- No checks inside a generic (check the instantiations) |
1299 | ||
ee6ba406 | 1300 | if Inside_A_Generic then |
1301 | return; | |
7aafae1c | 1302 | end if; |
ee6ba406 | 1303 | |
6fb3c314 | 1304 | -- Apply required constraint checks |
7aafae1c | 1305 | |
1306 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 1307 | Apply_Scalar_Range_Check (N, Typ); |
1308 | ||
1309 | elsif Is_Array_Type (Typ) then | |
1310 | ||
05fcfafb | 1311 | -- A useful optimization: an aggregate with only an others clause |
5f260d20 | 1312 | -- always has the right bounds. |
1313 | ||
1314 | if Nkind (N) = N_Aggregate | |
1315 | and then No (Expressions (N)) | |
1316 | and then Nkind | |
1317 | (First (Choices (First (Component_Associations (N))))) | |
1318 | = N_Others_Choice | |
1319 | then | |
1320 | return; | |
1321 | end if; | |
1322 | ||
ee6ba406 | 1323 | if Is_Constrained (Typ) then |
1324 | Apply_Length_Check (N, Typ); | |
1325 | ||
1326 | if No_Sliding then | |
1327 | Apply_Range_Check (N, Typ); | |
1328 | end if; | |
1329 | else | |
1330 | Apply_Range_Check (N, Typ); | |
1331 | end if; | |
1332 | ||
4fb5f0a0 | 1333 | elsif (Is_Record_Type (Typ) or else Is_Private_Type (Typ)) |
ee6ba406 | 1334 | and then Has_Discriminants (Base_Type (Typ)) |
1335 | and then Is_Constrained (Typ) | |
1336 | then | |
1337 | Apply_Discriminant_Check (N, Typ); | |
1338 | ||
1339 | elsif Is_Access_Type (Typ) then | |
1340 | ||
1341 | Desig_Typ := Designated_Type (Typ); | |
1342 | ||
1343 | -- No checks necessary if expression statically null | |
1344 | ||
2af58f67 | 1345 | if Known_Null (N) then |
00c403ee | 1346 | if Can_Never_Be_Null (Typ) then |
1347 | Install_Null_Excluding_Check (N); | |
1348 | end if; | |
ee6ba406 | 1349 | |
1350 | -- No sliding possible on access to arrays | |
1351 | ||
1352 | elsif Is_Array_Type (Desig_Typ) then | |
1353 | if Is_Constrained (Desig_Typ) then | |
1354 | Apply_Length_Check (N, Typ); | |
1355 | end if; | |
1356 | ||
1357 | Apply_Range_Check (N, Typ); | |
1358 | ||
a63a0aad | 1359 | -- Do not install a discriminant check for a constrained subtype |
1360 | -- created for an unconstrained nominal type because the subtype | |
1361 | -- has the correct constraints by construction. | |
1362 | ||
ee6ba406 | 1363 | elsif Has_Discriminants (Base_Type (Desig_Typ)) |
a63a0aad | 1364 | and then Is_Constrained (Desig_Typ) |
1365 | and then not Is_Constr_Subt_For_U_Nominal (Desig_Typ) | |
ee6ba406 | 1366 | then |
1367 | Apply_Discriminant_Check (N, Typ); | |
1368 | end if; | |
fa7497e8 | 1369 | |
bf3e1520 | 1370 | -- Apply the 2005 Null_Excluding check. Note that we do not apply |
00c403ee | 1371 | -- this check if the constraint node is illegal, as shown by having |
1372 | -- an error posted. This additional guard prevents cascaded errors | |
1373 | -- and compiler aborts on illegal programs involving Ada 2005 checks. | |
1374 | ||
fa7497e8 | 1375 | if Can_Never_Be_Null (Typ) |
1376 | and then not Can_Never_Be_Null (Etype (N)) | |
00c403ee | 1377 | and then not Error_Posted (N) |
fa7497e8 | 1378 | then |
1379 | Install_Null_Excluding_Check (N); | |
1380 | end if; | |
ee6ba406 | 1381 | end if; |
1382 | end Apply_Constraint_Check; | |
1383 | ||
1384 | ------------------------------ | |
1385 | -- Apply_Discriminant_Check -- | |
1386 | ------------------------------ | |
1387 | ||
1388 | procedure Apply_Discriminant_Check | |
1389 | (N : Node_Id; | |
1390 | Typ : Entity_Id; | |
1391 | Lhs : Node_Id := Empty) | |
1392 | is | |
1393 | Loc : constant Source_Ptr := Sloc (N); | |
1394 | Do_Access : constant Boolean := Is_Access_Type (Typ); | |
1395 | S_Typ : Entity_Id := Etype (N); | |
1396 | Cond : Node_Id; | |
1397 | T_Typ : Entity_Id; | |
1398 | ||
7be5088a | 1399 | function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean; |
1400 | -- A heap object with an indefinite subtype is constrained by its | |
1401 | -- initial value, and assigning to it requires a constraint_check. | |
1402 | -- The target may be an explicit dereference, or a renaming of one. | |
1403 | ||
ee6ba406 | 1404 | function Is_Aliased_Unconstrained_Component return Boolean; |
1405 | -- It is possible for an aliased component to have a nominal | |
1406 | -- unconstrained subtype (through instantiation). If this is a | |
1407 | -- discriminated component assigned in the expansion of an aggregate | |
1408 | -- in an initialization, the check must be suppressed. This unusual | |
2af58f67 | 1409 | -- situation requires a predicate of its own. |
ee6ba406 | 1410 | |
7be5088a | 1411 | ---------------------------------- |
1412 | -- Denotes_Explicit_Dereference -- | |
1413 | ---------------------------------- | |
1414 | ||
1415 | function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean is | |
1416 | begin | |
1417 | return | |
1418 | Nkind (Obj) = N_Explicit_Dereference | |
1419 | or else | |
1420 | (Is_Entity_Name (Obj) | |
1421 | and then Present (Renamed_Object (Entity (Obj))) | |
9474aa9c | 1422 | and then Nkind (Renamed_Object (Entity (Obj))) = |
1423 | N_Explicit_Dereference); | |
7be5088a | 1424 | end Denotes_Explicit_Dereference; |
1425 | ||
ee6ba406 | 1426 | ---------------------------------------- |
1427 | -- Is_Aliased_Unconstrained_Component -- | |
1428 | ---------------------------------------- | |
1429 | ||
1430 | function Is_Aliased_Unconstrained_Component return Boolean is | |
1431 | Comp : Entity_Id; | |
1432 | Pref : Node_Id; | |
1433 | ||
1434 | begin | |
1435 | if Nkind (Lhs) /= N_Selected_Component then | |
1436 | return False; | |
1437 | else | |
1438 | Comp := Entity (Selector_Name (Lhs)); | |
1439 | Pref := Prefix (Lhs); | |
1440 | end if; | |
1441 | ||
1442 | if Ekind (Comp) /= E_Component | |
1443 | or else not Is_Aliased (Comp) | |
1444 | then | |
1445 | return False; | |
1446 | end if; | |
1447 | ||
1448 | return not Comes_From_Source (Pref) | |
1449 | and then In_Instance | |
1450 | and then not Is_Constrained (Etype (Comp)); | |
1451 | end Is_Aliased_Unconstrained_Component; | |
1452 | ||
1453 | -- Start of processing for Apply_Discriminant_Check | |
1454 | ||
1455 | begin | |
1456 | if Do_Access then | |
1457 | T_Typ := Designated_Type (Typ); | |
1458 | else | |
1459 | T_Typ := Typ; | |
1460 | end if; | |
1461 | ||
105fa703 | 1462 | -- If the expression is a function call that returns a limited object |
1463 | -- it cannot be copied. It is not clear how to perform the proper | |
1464 | -- discriminant check in this case because the discriminant value must | |
1465 | -- be retrieved from the constructed object itself. | |
1466 | ||
1467 | if Nkind (N) = N_Function_Call | |
1468 | and then Is_Limited_Type (Typ) | |
1469 | and then Is_Entity_Name (Name (N)) | |
1470 | and then Returns_By_Ref (Entity (Name (N))) | |
1471 | then | |
1472 | return; | |
1473 | end if; | |
1474 | ||
f0d65dae | 1475 | -- Only apply checks when generating code and discriminant checks are |
1476 | -- not suppressed. In GNATprove mode, we do not apply the checks, but we | |
1477 | -- still analyze the expression to possibly issue errors on SPARK code | |
1478 | -- when a run-time error can be detected at compile time. | |
1479 | ||
1480 | if not GNATprove_Mode then | |
1481 | if not Expander_Active | |
1482 | or else Discriminant_Checks_Suppressed (T_Typ) | |
1483 | then | |
1484 | return; | |
1485 | end if; | |
ee6ba406 | 1486 | end if; |
1487 | ||
feff2f05 | 1488 | -- No discriminant checks necessary for an access when expression is |
1489 | -- statically Null. This is not only an optimization, it is fundamental | |
1490 | -- because otherwise discriminant checks may be generated in init procs | |
1491 | -- for types containing an access to a not-yet-frozen record, causing a | |
1492 | -- deadly forward reference. | |
ee6ba406 | 1493 | |
feff2f05 | 1494 | -- Also, if the expression is of an access type whose designated type is |
1495 | -- incomplete, then the access value must be null and we suppress the | |
1496 | -- check. | |
ee6ba406 | 1497 | |
2af58f67 | 1498 | if Known_Null (N) then |
ee6ba406 | 1499 | return; |
1500 | ||
1501 | elsif Is_Access_Type (S_Typ) then | |
1502 | S_Typ := Designated_Type (S_Typ); | |
1503 | ||
1504 | if Ekind (S_Typ) = E_Incomplete_Type then | |
1505 | return; | |
1506 | end if; | |
1507 | end if; | |
1508 | ||
0577b0b1 | 1509 | -- If an assignment target is present, then we need to generate the |
1510 | -- actual subtype if the target is a parameter or aliased object with | |
1511 | -- an unconstrained nominal subtype. | |
1512 | ||
1513 | -- Ada 2005 (AI-363): For Ada 2005, we limit the building of the actual | |
1514 | -- subtype to the parameter and dereference cases, since other aliased | |
1515 | -- objects are unconstrained (unless the nominal subtype is explicitly | |
7be5088a | 1516 | -- constrained). |
ee6ba406 | 1517 | |
1518 | if Present (Lhs) | |
1519 | and then (Present (Param_Entity (Lhs)) | |
de54c5ab | 1520 | or else (Ada_Version < Ada_2005 |
0577b0b1 | 1521 | and then not Is_Constrained (T_Typ) |
ee6ba406 | 1522 | and then Is_Aliased_View (Lhs) |
0577b0b1 | 1523 | and then not Is_Aliased_Unconstrained_Component) |
de54c5ab | 1524 | or else (Ada_Version >= Ada_2005 |
0577b0b1 | 1525 | and then not Is_Constrained (T_Typ) |
7be5088a | 1526 | and then Denotes_Explicit_Dereference (Lhs) |
0577b0b1 | 1527 | and then Nkind (Original_Node (Lhs)) /= |
1528 | N_Function_Call)) | |
ee6ba406 | 1529 | then |
1530 | T_Typ := Get_Actual_Subtype (Lhs); | |
1531 | end if; | |
1532 | ||
feff2f05 | 1533 | -- Nothing to do if the type is unconstrained (this is the case where |
1534 | -- the actual subtype in the RM sense of N is unconstrained and no check | |
1535 | -- is required). | |
ee6ba406 | 1536 | |
1537 | if not Is_Constrained (T_Typ) then | |
1538 | return; | |
05fcfafb | 1539 | |
1540 | -- Ada 2005: nothing to do if the type is one for which there is a | |
1541 | -- partial view that is constrained. | |
1542 | ||
de54c5ab | 1543 | elsif Ada_Version >= Ada_2005 |
0d78d2d4 | 1544 | and then Object_Type_Has_Constrained_Partial_View |
d41a3f41 | 1545 | (Typ => Base_Type (T_Typ), |
1546 | Scop => Current_Scope) | |
05fcfafb | 1547 | then |
1548 | return; | |
ee6ba406 | 1549 | end if; |
1550 | ||
00f91aef | 1551 | -- Nothing to do if the type is an Unchecked_Union |
1552 | ||
1553 | if Is_Unchecked_Union (Base_Type (T_Typ)) then | |
1554 | return; | |
1555 | end if; | |
1556 | ||
8d11916f | 1557 | -- Suppress checks if the subtypes are the same. The check must be |
feff2f05 | 1558 | -- preserved in an assignment to a formal, because the constraint is |
1559 | -- given by the actual. | |
ee6ba406 | 1560 | |
1561 | if Nkind (Original_Node (N)) /= N_Allocator | |
1562 | and then (No (Lhs) | |
8143bf7c | 1563 | or else not Is_Entity_Name (Lhs) |
1564 | or else No (Param_Entity (Lhs))) | |
ee6ba406 | 1565 | then |
1566 | if (Etype (N) = Typ | |
1567 | or else (Do_Access and then Designated_Type (Typ) = S_Typ)) | |
1568 | and then not Is_Aliased_View (Lhs) | |
1569 | then | |
1570 | return; | |
1571 | end if; | |
1572 | ||
feff2f05 | 1573 | -- We can also eliminate checks on allocators with a subtype mark that |
1574 | -- coincides with the context type. The context type may be a subtype | |
1575 | -- without a constraint (common case, a generic actual). | |
ee6ba406 | 1576 | |
1577 | elsif Nkind (Original_Node (N)) = N_Allocator | |
1578 | and then Is_Entity_Name (Expression (Original_Node (N))) | |
1579 | then | |
1580 | declare | |
9dfe12ae | 1581 | Alloc_Typ : constant Entity_Id := |
b6341c67 | 1582 | Entity (Expression (Original_Node (N))); |
ee6ba406 | 1583 | |
1584 | begin | |
1585 | if Alloc_Typ = T_Typ | |
1586 | or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration | |
1587 | and then Is_Entity_Name ( | |
1588 | Subtype_Indication (Parent (T_Typ))) | |
1589 | and then Alloc_Typ = Base_Type (T_Typ)) | |
1590 | ||
1591 | then | |
1592 | return; | |
1593 | end if; | |
1594 | end; | |
1595 | end if; | |
1596 | ||
feff2f05 | 1597 | -- See if we have a case where the types are both constrained, and all |
1598 | -- the constraints are constants. In this case, we can do the check | |
1599 | -- successfully at compile time. | |
ee6ba406 | 1600 | |
8d11916f | 1601 | -- We skip this check for the case where the node is rewritten as |
d7ec9a29 | 1602 | -- an allocator, because it already carries the context subtype, |
1603 | -- and extracting the discriminants from the aggregate is messy. | |
ee6ba406 | 1604 | |
1605 | if Is_Constrained (S_Typ) | |
1606 | and then Nkind (Original_Node (N)) /= N_Allocator | |
1607 | then | |
1608 | declare | |
1609 | DconT : Elmt_Id; | |
1610 | Discr : Entity_Id; | |
1611 | DconS : Elmt_Id; | |
1612 | ItemS : Node_Id; | |
1613 | ItemT : Node_Id; | |
1614 | ||
1615 | begin | |
1616 | -- S_Typ may not have discriminants in the case where it is a | |
feff2f05 | 1617 | -- private type completed by a default discriminated type. In that |
8d11916f | 1618 | -- case, we need to get the constraints from the underlying type. |
feff2f05 | 1619 | -- If the underlying type is unconstrained (i.e. has no default |
1620 | -- discriminants) no check is needed. | |
ee6ba406 | 1621 | |
1622 | if Has_Discriminants (S_Typ) then | |
1623 | Discr := First_Discriminant (S_Typ); | |
1624 | DconS := First_Elmt (Discriminant_Constraint (S_Typ)); | |
1625 | ||
1626 | else | |
1627 | Discr := First_Discriminant (Underlying_Type (S_Typ)); | |
1628 | DconS := | |
1629 | First_Elmt | |
1630 | (Discriminant_Constraint (Underlying_Type (S_Typ))); | |
1631 | ||
1632 | if No (DconS) then | |
1633 | return; | |
1634 | end if; | |
fccb5da7 | 1635 | |
1636 | -- A further optimization: if T_Typ is derived from S_Typ | |
1637 | -- without imposing a constraint, no check is needed. | |
1638 | ||
1639 | if Nkind (Original_Node (Parent (T_Typ))) = | |
1640 | N_Full_Type_Declaration | |
1641 | then | |
1642 | declare | |
5c61a0ff | 1643 | Type_Def : constant Node_Id := |
b6341c67 | 1644 | Type_Definition (Original_Node (Parent (T_Typ))); |
fccb5da7 | 1645 | begin |
1646 | if Nkind (Type_Def) = N_Derived_Type_Definition | |
1647 | and then Is_Entity_Name (Subtype_Indication (Type_Def)) | |
1648 | and then Entity (Subtype_Indication (Type_Def)) = S_Typ | |
1649 | then | |
1650 | return; | |
1651 | end if; | |
1652 | end; | |
1653 | end if; | |
ee6ba406 | 1654 | end if; |
1655 | ||
86594966 | 1656 | -- Constraint may appear in full view of type |
1657 | ||
1658 | if Ekind (T_Typ) = E_Private_Subtype | |
1659 | and then Present (Full_View (T_Typ)) | |
1660 | then | |
d7ec9a29 | 1661 | DconT := |
86594966 | 1662 | First_Elmt (Discriminant_Constraint (Full_View (T_Typ))); |
86594966 | 1663 | else |
d7ec9a29 | 1664 | DconT := |
1665 | First_Elmt (Discriminant_Constraint (T_Typ)); | |
86594966 | 1666 | end if; |
ee6ba406 | 1667 | |
1668 | while Present (Discr) loop | |
1669 | ItemS := Node (DconS); | |
1670 | ItemT := Node (DconT); | |
1671 | ||
00c403ee | 1672 | -- For a discriminated component type constrained by the |
1673 | -- current instance of an enclosing type, there is no | |
1674 | -- applicable discriminant check. | |
1675 | ||
1676 | if Nkind (ItemT) = N_Attribute_Reference | |
1677 | and then Is_Access_Type (Etype (ItemT)) | |
1678 | and then Is_Entity_Name (Prefix (ItemT)) | |
1679 | and then Is_Type (Entity (Prefix (ItemT))) | |
1680 | then | |
1681 | return; | |
1682 | end if; | |
1683 | ||
cc60bd16 | 1684 | -- If the expressions for the discriminants are identical |
1685 | -- and it is side-effect free (for now just an entity), | |
1686 | -- this may be a shared constraint, e.g. from a subtype | |
1687 | -- without a constraint introduced as a generic actual. | |
1688 | -- Examine other discriminants if any. | |
1689 | ||
1690 | if ItemS = ItemT | |
1691 | and then Is_Entity_Name (ItemS) | |
1692 | then | |
1693 | null; | |
1694 | ||
1695 | elsif not Is_OK_Static_Expression (ItemS) | |
1696 | or else not Is_OK_Static_Expression (ItemT) | |
1697 | then | |
1698 | exit; | |
ee6ba406 | 1699 | |
cc60bd16 | 1700 | elsif Expr_Value (ItemS) /= Expr_Value (ItemT) then |
ee6ba406 | 1701 | if Do_Access then -- needs run-time check. |
1702 | exit; | |
1703 | else | |
1704 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 1705 | (N, "incorrect value for discriminant&??", |
f15731c4 | 1706 | CE_Discriminant_Check_Failed, Ent => Discr); |
ee6ba406 | 1707 | return; |
1708 | end if; | |
1709 | end if; | |
1710 | ||
1711 | Next_Elmt (DconS); | |
1712 | Next_Elmt (DconT); | |
1713 | Next_Discriminant (Discr); | |
1714 | end loop; | |
1715 | ||
1716 | if No (Discr) then | |
1717 | return; | |
1718 | end if; | |
1719 | end; | |
1720 | end if; | |
1721 | ||
f0d65dae | 1722 | -- In GNATprove mode, we do not apply the checks |
1723 | ||
1724 | if GNATprove_Mode then | |
1725 | return; | |
1726 | end if; | |
1727 | ||
ee6ba406 | 1728 | -- Here we need a discriminant check. First build the expression |
1729 | -- for the comparisons of the discriminants: | |
1730 | ||
1731 | -- (n.disc1 /= typ.disc1) or else | |
1732 | -- (n.disc2 /= typ.disc2) or else | |
1733 | -- ... | |
1734 | -- (n.discn /= typ.discn) | |
1735 | ||
1736 | Cond := Build_Discriminant_Checks (N, T_Typ); | |
1737 | ||
3cce7f32 | 1738 | -- If Lhs is set and is a parameter, then the condition is guarded by: |
1739 | -- lhs'constrained and then (condition built above) | |
ee6ba406 | 1740 | |
1741 | if Present (Param_Entity (Lhs)) then | |
1742 | Cond := | |
1743 | Make_And_Then (Loc, | |
1744 | Left_Opnd => | |
1745 | Make_Attribute_Reference (Loc, | |
1746 | Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc), | |
1747 | Attribute_Name => Name_Constrained), | |
1748 | Right_Opnd => Cond); | |
1749 | end if; | |
1750 | ||
1751 | if Do_Access then | |
1752 | Cond := Guard_Access (Cond, Loc, N); | |
1753 | end if; | |
1754 | ||
1755 | Insert_Action (N, | |
f15731c4 | 1756 | Make_Raise_Constraint_Error (Loc, |
1757 | Condition => Cond, | |
1758 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 1759 | end Apply_Discriminant_Check; |
1760 | ||
2fe22c69 | 1761 | ------------------------- |
1762 | -- Apply_Divide_Checks -- | |
1763 | ------------------------- | |
ee6ba406 | 1764 | |
2fe22c69 | 1765 | procedure Apply_Divide_Checks (N : Node_Id) is |
ee6ba406 | 1766 | Loc : constant Source_Ptr := Sloc (N); |
1767 | Typ : constant Entity_Id := Etype (N); | |
1768 | Left : constant Node_Id := Left_Opnd (N); | |
1769 | Right : constant Node_Id := Right_Opnd (N); | |
1770 | ||
db415383 | 1771 | Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
2fe22c69 | 1772 | -- Current overflow checking mode |
1773 | ||
ee6ba406 | 1774 | LLB : Uint; |
1775 | Llo : Uint; | |
1776 | Lhi : Uint; | |
1777 | LOK : Boolean; | |
1778 | Rlo : Uint; | |
1779 | Rhi : Uint; | |
2fe22c69 | 1780 | ROK : Boolean; |
96da3284 | 1781 | |
1782 | pragma Warnings (Off, Lhi); | |
1783 | -- Don't actually use this value | |
ee6ba406 | 1784 | |
1785 | begin | |
0df9d43f | 1786 | -- If we are operating in MINIMIZED or ELIMINATED mode, and we are |
1787 | -- operating on signed integer types, then the only thing this routine | |
1788 | -- does is to call Apply_Arithmetic_Overflow_Minimized_Eliminated. That | |
1789 | -- procedure will (possibly later on during recursive downward calls), | |
1790 | -- ensure that any needed overflow/division checks are properly applied. | |
2fe22c69 | 1791 | |
1792 | if Mode in Minimized_Or_Eliminated | |
2fe22c69 | 1793 | and then Is_Signed_Integer_Type (Typ) |
1794 | then | |
1795 | Apply_Arithmetic_Overflow_Minimized_Eliminated (N); | |
1796 | return; | |
1797 | end if; | |
1798 | ||
1799 | -- Proceed here in SUPPRESSED or CHECKED modes | |
1800 | ||
a33565dd | 1801 | if Expander_Active |
13dbf220 | 1802 | and then not Backend_Divide_Checks_On_Target |
1803 | and then Check_Needed (Right, Division_Check) | |
ee6ba406 | 1804 | then |
9c486805 | 1805 | Determine_Range (Right, ROK, Rlo, Rhi, Assume_Valid => True); |
ee6ba406 | 1806 | |
2fe22c69 | 1807 | -- Deal with division check |
ee6ba406 | 1808 | |
2fe22c69 | 1809 | if Do_Division_Check (N) |
1810 | and then not Division_Checks_Suppressed (Typ) | |
1811 | then | |
1812 | Apply_Division_Check (N, Rlo, Rhi, ROK); | |
ee6ba406 | 1813 | end if; |
1814 | ||
2fe22c69 | 1815 | -- Deal with overflow check |
1816 | ||
0df9d43f | 1817 | if Do_Overflow_Check (N) |
1818 | and then not Overflow_Checks_Suppressed (Etype (N)) | |
1819 | then | |
f3ccbbb3 | 1820 | Set_Do_Overflow_Check (N, False); |
1821 | ||
2fe22c69 | 1822 | -- Test for extremely annoying case of xxx'First divided by -1 |
1823 | -- for division of signed integer types (only overflow case). | |
ee6ba406 | 1824 | |
ee6ba406 | 1825 | if Nkind (N) = N_Op_Divide |
1826 | and then Is_Signed_Integer_Type (Typ) | |
1827 | then | |
9c486805 | 1828 | Determine_Range (Left, LOK, Llo, Lhi, Assume_Valid => True); |
ee6ba406 | 1829 | LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ))); |
1830 | ||
1831 | if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) | |
2fe22c69 | 1832 | and then |
1833 | ((not LOK) or else (Llo = LLB)) | |
ee6ba406 | 1834 | then |
f72e7b2a | 1835 | -- Ensure that expressions are not evaluated twice (once |
1836 | -- for their runtime checks and once for their regular | |
1837 | -- computation). | |
1838 | ||
1839 | Force_Evaluation (Left, Mode => Strict); | |
1840 | Force_Evaluation (Right, Mode => Strict); | |
1841 | ||
ee6ba406 | 1842 | Insert_Action (N, |
1843 | Make_Raise_Constraint_Error (Loc, | |
1844 | Condition => | |
1845 | Make_And_Then (Loc, | |
2fe22c69 | 1846 | Left_Opnd => |
1847 | Make_Op_Eq (Loc, | |
1848 | Left_Opnd => | |
1849 | Duplicate_Subexpr_Move_Checks (Left), | |
1850 | Right_Opnd => Make_Integer_Literal (Loc, LLB)), | |
ee6ba406 | 1851 | |
2fe22c69 | 1852 | Right_Opnd => |
1853 | Make_Op_Eq (Loc, | |
1854 | Left_Opnd => Duplicate_Subexpr (Right), | |
1855 | Right_Opnd => Make_Integer_Literal (Loc, -1))), | |
ee6ba406 | 1856 | |
f15731c4 | 1857 | Reason => CE_Overflow_Check_Failed)); |
ee6ba406 | 1858 | end if; |
1859 | end if; | |
1860 | end if; | |
1861 | end if; | |
2fe22c69 | 1862 | end Apply_Divide_Checks; |
1863 | ||
1864 | -------------------------- | |
1865 | -- Apply_Division_Check -- | |
1866 | -------------------------- | |
1867 | ||
1868 | procedure Apply_Division_Check | |
1869 | (N : Node_Id; | |
1870 | Rlo : Uint; | |
1871 | Rhi : Uint; | |
1872 | ROK : Boolean) | |
1873 | is | |
1874 | pragma Assert (Do_Division_Check (N)); | |
1875 | ||
1876 | Loc : constant Source_Ptr := Sloc (N); | |
f81a201b | 1877 | Right : constant Node_Id := Right_Opnd (N); |
1878 | Opnd : Node_Id; | |
2fe22c69 | 1879 | |
1880 | begin | |
a33565dd | 1881 | if Expander_Active |
2fe22c69 | 1882 | and then not Backend_Divide_Checks_On_Target |
1883 | and then Check_Needed (Right, Division_Check) | |
2fe22c69 | 1884 | |
f81a201b | 1885 | -- See if division by zero possible, and if so generate test. This |
1886 | -- part of the test is not controlled by the -gnato switch, since it | |
1887 | -- is a Division_Check and not an Overflow_Check. | |
f3ccbbb3 | 1888 | |
f81a201b | 1889 | and then Do_Division_Check (N) |
1890 | then | |
1891 | Set_Do_Division_Check (N, False); | |
75f4b34c | 1892 | |
f81a201b | 1893 | if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then |
1894 | if Is_Floating_Point_Type (Etype (N)) then | |
1895 | Opnd := Make_Real_Literal (Loc, Ureal_0); | |
1896 | else | |
1897 | Opnd := Make_Integer_Literal (Loc, 0); | |
2fe22c69 | 1898 | end if; |
f81a201b | 1899 | |
1900 | Insert_Action (N, | |
1901 | Make_Raise_Constraint_Error (Loc, | |
1902 | Condition => | |
1903 | Make_Op_Eq (Loc, | |
1904 | Left_Opnd => Duplicate_Subexpr_Move_Checks (Right), | |
1905 | Right_Opnd => Opnd), | |
1906 | Reason => CE_Divide_By_Zero)); | |
2fe22c69 | 1907 | end if; |
1908 | end if; | |
1909 | end Apply_Division_Check; | |
ee6ba406 | 1910 | |
5329ca64 | 1911 | ---------------------------------- |
1912 | -- Apply_Float_Conversion_Check -- | |
1913 | ---------------------------------- | |
1914 | ||
feff2f05 | 1915 | -- Let F and I be the source and target types of the conversion. The RM |
1916 | -- specifies that a floating-point value X is rounded to the nearest | |
1917 | -- integer, with halfway cases being rounded away from zero. The rounded | |
1918 | -- value of X is checked against I'Range. | |
1919 | ||
1920 | -- The catch in the above paragraph is that there is no good way to know | |
1921 | -- whether the round-to-integer operation resulted in overflow. A remedy is | |
1922 | -- to perform a range check in the floating-point domain instead, however: | |
5329ca64 | 1923 | |
5329ca64 | 1924 | -- (1) The bounds may not be known at compile time |
2af58f67 | 1925 | -- (2) The check must take into account rounding or truncation. |
5329ca64 | 1926 | -- (3) The range of type I may not be exactly representable in F. |
2af58f67 | 1927 | -- (4) For the rounding case, The end-points I'First - 0.5 and |
1928 | -- I'Last + 0.5 may or may not be in range, depending on the | |
1929 | -- sign of I'First and I'Last. | |
5329ca64 | 1930 | -- (5) X may be a NaN, which will fail any comparison |
1931 | ||
2af58f67 | 1932 | -- The following steps correctly convert X with rounding: |
feff2f05 | 1933 | |
5329ca64 | 1934 | -- (1) If either I'First or I'Last is not known at compile time, use |
1935 | -- I'Base instead of I in the next three steps and perform a | |
1936 | -- regular range check against I'Range after conversion. | |
1937 | -- (2) If I'First - 0.5 is representable in F then let Lo be that | |
1938 | -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be | |
2af58f67 | 1939 | -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First). |
1940 | -- In other words, take one of the closest floating-point numbers | |
1941 | -- (which is an integer value) to I'First, and see if it is in | |
1942 | -- range or not. | |
5329ca64 | 1943 | -- (3) If I'Last + 0.5 is representable in F then let Hi be that value |
1944 | -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be | |
2af58f67 | 1945 | -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last). |
5329ca64 | 1946 | -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo) |
1947 | -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi) | |
1948 | ||
2af58f67 | 1949 | -- For the truncating case, replace steps (2) and (3) as follows: |
1950 | -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK | |
1951 | -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let | |
1952 | -- Lo_OK be True. | |
1953 | -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK | |
1954 | -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let | |
141d591a | 1955 | -- Hi_OK be True. |
2af58f67 | 1956 | |
5329ca64 | 1957 | procedure Apply_Float_Conversion_Check |
1958 | (Ck_Node : Node_Id; | |
1959 | Target_Typ : Entity_Id) | |
1960 | is | |
feff2f05 | 1961 | LB : constant Node_Id := Type_Low_Bound (Target_Typ); |
1962 | HB : constant Node_Id := Type_High_Bound (Target_Typ); | |
5329ca64 | 1963 | Loc : constant Source_Ptr := Sloc (Ck_Node); |
1964 | Expr_Type : constant Entity_Id := Base_Type (Etype (Ck_Node)); | |
feff2f05 | 1965 | Target_Base : constant Entity_Id := |
b6341c67 | 1966 | Implementation_Base_Type (Target_Typ); |
feff2f05 | 1967 | |
2af58f67 | 1968 | Par : constant Node_Id := Parent (Ck_Node); |
1969 | pragma Assert (Nkind (Par) = N_Type_Conversion); | |
1970 | -- Parent of check node, must be a type conversion | |
1971 | ||
1972 | Truncate : constant Boolean := Float_Truncate (Par); | |
1973 | Max_Bound : constant Uint := | |
b6341c67 | 1974 | UI_Expon |
1975 | (Machine_Radix_Value (Expr_Type), | |
1976 | Machine_Mantissa_Value (Expr_Type) - 1) - 1; | |
2af58f67 | 1977 | |
5329ca64 | 1978 | -- Largest bound, so bound plus or minus half is a machine number of F |
1979 | ||
feff2f05 | 1980 | Ifirst, Ilast : Uint; |
1981 | -- Bounds of integer type | |
1982 | ||
1983 | Lo, Hi : Ureal; | |
1984 | -- Bounds to check in floating-point domain | |
5329ca64 | 1985 | |
feff2f05 | 1986 | Lo_OK, Hi_OK : Boolean; |
1987 | -- True iff Lo resp. Hi belongs to I'Range | |
5329ca64 | 1988 | |
feff2f05 | 1989 | Lo_Chk, Hi_Chk : Node_Id; |
1990 | -- Expressions that are False iff check fails | |
1991 | ||
1992 | Reason : RT_Exception_Code; | |
5329ca64 | 1993 | |
1994 | begin | |
41f06abf | 1995 | -- We do not need checks if we are not generating code (i.e. the full |
1996 | -- expander is not active). In SPARK mode, we specifically don't want | |
1997 | -- the frontend to expand these checks, which are dealt with directly | |
1998 | -- in the formal verification backend. | |
1999 | ||
a33565dd | 2000 | if not Expander_Active then |
41f06abf | 2001 | return; |
2002 | end if; | |
2003 | ||
5329ca64 | 2004 | if not Compile_Time_Known_Value (LB) |
2005 | or not Compile_Time_Known_Value (HB) | |
2006 | then | |
2007 | declare | |
feff2f05 | 2008 | -- First check that the value falls in the range of the base type, |
2009 | -- to prevent overflow during conversion and then perform a | |
2010 | -- regular range check against the (dynamic) bounds. | |
5329ca64 | 2011 | |
5329ca64 | 2012 | pragma Assert (Target_Base /= Target_Typ); |
5329ca64 | 2013 | |
46eb6933 | 2014 | Temp : constant Entity_Id := Make_Temporary (Loc, 'T', Par); |
5329ca64 | 2015 | |
2016 | begin | |
2017 | Apply_Float_Conversion_Check (Ck_Node, Target_Base); | |
2018 | Set_Etype (Temp, Target_Base); | |
2019 | ||
2020 | Insert_Action (Parent (Par), | |
2021 | Make_Object_Declaration (Loc, | |
2022 | Defining_Identifier => Temp, | |
2023 | Object_Definition => New_Occurrence_Of (Target_Typ, Loc), | |
2024 | Expression => New_Copy_Tree (Par)), | |
2025 | Suppress => All_Checks); | |
2026 | ||
2027 | Insert_Action (Par, | |
2028 | Make_Raise_Constraint_Error (Loc, | |
2029 | Condition => | |
2030 | Make_Not_In (Loc, | |
2031 | Left_Opnd => New_Occurrence_Of (Temp, Loc), | |
2032 | Right_Opnd => New_Occurrence_Of (Target_Typ, Loc)), | |
2033 | Reason => CE_Range_Check_Failed)); | |
2034 | Rewrite (Par, New_Occurrence_Of (Temp, Loc)); | |
2035 | ||
2036 | return; | |
2037 | end; | |
2038 | end if; | |
2039 | ||
7d86aa98 | 2040 | -- Get the (static) bounds of the target type |
5329ca64 | 2041 | |
2042 | Ifirst := Expr_Value (LB); | |
2043 | Ilast := Expr_Value (HB); | |
2044 | ||
7d86aa98 | 2045 | -- A simple optimization: if the expression is a universal literal, |
2046 | -- we can do the comparison with the bounds and the conversion to | |
2047 | -- an integer type statically. The range checks are unchanged. | |
2048 | ||
2049 | if Nkind (Ck_Node) = N_Real_Literal | |
2050 | and then Etype (Ck_Node) = Universal_Real | |
2051 | and then Is_Integer_Type (Target_Typ) | |
2052 | and then Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
2053 | then | |
2054 | declare | |
2055 | Int_Val : constant Uint := UR_To_Uint (Realval (Ck_Node)); | |
2056 | ||
2057 | begin | |
2058 | if Int_Val <= Ilast and then Int_Val >= Ifirst then | |
2059 | ||
4309515d | 2060 | -- Conversion is safe |
7d86aa98 | 2061 | |
2062 | Rewrite (Parent (Ck_Node), | |
2063 | Make_Integer_Literal (Loc, UI_To_Int (Int_Val))); | |
2064 | Analyze_And_Resolve (Parent (Ck_Node), Target_Typ); | |
2065 | return; | |
2066 | end if; | |
2067 | end; | |
2068 | end if; | |
2069 | ||
5329ca64 | 2070 | -- Check against lower bound |
2071 | ||
2af58f67 | 2072 | if Truncate and then Ifirst > 0 then |
2073 | Lo := Pred (Expr_Type, UR_From_Uint (Ifirst)); | |
2074 | Lo_OK := False; | |
2075 | ||
2076 | elsif Truncate then | |
2077 | Lo := Succ (Expr_Type, UR_From_Uint (Ifirst - 1)); | |
2078 | Lo_OK := True; | |
2079 | ||
2080 | elsif abs (Ifirst) < Max_Bound then | |
5329ca64 | 2081 | Lo := UR_From_Uint (Ifirst) - Ureal_Half; |
2082 | Lo_OK := (Ifirst > 0); | |
2af58f67 | 2083 | |
5329ca64 | 2084 | else |
2085 | Lo := Machine (Expr_Type, UR_From_Uint (Ifirst), Round_Even, Ck_Node); | |
2086 | Lo_OK := (Lo >= UR_From_Uint (Ifirst)); | |
2087 | end if; | |
2088 | ||
2089 | if Lo_OK then | |
2090 | ||
2091 | -- Lo_Chk := (X >= Lo) | |
2092 | ||
2093 | Lo_Chk := Make_Op_Ge (Loc, | |
2094 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2095 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
2096 | ||
2097 | else | |
2098 | -- Lo_Chk := (X > Lo) | |
2099 | ||
2100 | Lo_Chk := Make_Op_Gt (Loc, | |
2101 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2102 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
2103 | end if; | |
2104 | ||
2105 | -- Check against higher bound | |
2106 | ||
2af58f67 | 2107 | if Truncate and then Ilast < 0 then |
2108 | Hi := Succ (Expr_Type, UR_From_Uint (Ilast)); | |
b2c42753 | 2109 | Hi_OK := False; |
2af58f67 | 2110 | |
2111 | elsif Truncate then | |
2112 | Hi := Pred (Expr_Type, UR_From_Uint (Ilast + 1)); | |
2113 | Hi_OK := True; | |
2114 | ||
2115 | elsif abs (Ilast) < Max_Bound then | |
5329ca64 | 2116 | Hi := UR_From_Uint (Ilast) + Ureal_Half; |
2117 | Hi_OK := (Ilast < 0); | |
2118 | else | |
2119 | Hi := Machine (Expr_Type, UR_From_Uint (Ilast), Round_Even, Ck_Node); | |
2120 | Hi_OK := (Hi <= UR_From_Uint (Ilast)); | |
2121 | end if; | |
2122 | ||
2123 | if Hi_OK then | |
2124 | ||
2125 | -- Hi_Chk := (X <= Hi) | |
2126 | ||
2127 | Hi_Chk := Make_Op_Le (Loc, | |
2128 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2129 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
2130 | ||
2131 | else | |
2132 | -- Hi_Chk := (X < Hi) | |
2133 | ||
2134 | Hi_Chk := Make_Op_Lt (Loc, | |
2135 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2136 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
2137 | end if; | |
2138 | ||
feff2f05 | 2139 | -- If the bounds of the target type are the same as those of the base |
2140 | -- type, the check is an overflow check as a range check is not | |
2141 | -- performed in these cases. | |
5329ca64 | 2142 | |
2143 | if Expr_Value (Type_Low_Bound (Target_Base)) = Ifirst | |
2144 | and then Expr_Value (Type_High_Bound (Target_Base)) = Ilast | |
2145 | then | |
2146 | Reason := CE_Overflow_Check_Failed; | |
2147 | else | |
2148 | Reason := CE_Range_Check_Failed; | |
2149 | end if; | |
2150 | ||
2151 | -- Raise CE if either conditions does not hold | |
2152 | ||
2153 | Insert_Action (Ck_Node, | |
2154 | Make_Raise_Constraint_Error (Loc, | |
05fcfafb | 2155 | Condition => Make_Op_Not (Loc, Make_And_Then (Loc, Lo_Chk, Hi_Chk)), |
5329ca64 | 2156 | Reason => Reason)); |
2157 | end Apply_Float_Conversion_Check; | |
2158 | ||
ee6ba406 | 2159 | ------------------------ |
2160 | -- Apply_Length_Check -- | |
2161 | ------------------------ | |
2162 | ||
2163 | procedure Apply_Length_Check | |
2164 | (Ck_Node : Node_Id; | |
2165 | Target_Typ : Entity_Id; | |
2166 | Source_Typ : Entity_Id := Empty) | |
2167 | is | |
2168 | begin | |
2169 | Apply_Selected_Length_Checks | |
2170 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
2171 | end Apply_Length_Check; | |
2172 | ||
3b045963 | 2173 | ------------------------------------- |
2174 | -- Apply_Parameter_Aliasing_Checks -- | |
2175 | ------------------------------------- | |
b73adb97 | 2176 | |
3b045963 | 2177 | procedure Apply_Parameter_Aliasing_Checks |
2178 | (Call : Node_Id; | |
2179 | Subp : Entity_Id) | |
2180 | is | |
bb569db0 | 2181 | Loc : constant Source_Ptr := Sloc (Call); |
2182 | ||
3b045963 | 2183 | function May_Cause_Aliasing |
2184 | (Formal_1 : Entity_Id; | |
2185 | Formal_2 : Entity_Id) return Boolean; | |
2186 | -- Determine whether two formal parameters can alias each other | |
2187 | -- depending on their modes. | |
2188 | ||
2189 | function Original_Actual (N : Node_Id) return Node_Id; | |
2190 | -- The expander may replace an actual with a temporary for the sake of | |
2191 | -- side effect removal. The temporary may hide a potential aliasing as | |
2192 | -- it does not share the address of the actual. This routine attempts | |
2193 | -- to retrieve the original actual. | |
2194 | ||
bb569db0 | 2195 | procedure Overlap_Check |
2196 | (Actual_1 : Node_Id; | |
2197 | Actual_2 : Node_Id; | |
2198 | Formal_1 : Entity_Id; | |
2199 | Formal_2 : Entity_Id; | |
2200 | Check : in out Node_Id); | |
2201 | -- Create a check to determine whether Actual_1 overlaps with Actual_2. | |
2202 | -- If detailed exception messages are enabled, the check is augmented to | |
2203 | -- provide information about the names of the corresponding formals. See | |
2204 | -- the body for details. Actual_1 and Actual_2 denote the two actuals to | |
2205 | -- be tested. Formal_1 and Formal_2 denote the corresponding formals. | |
2206 | -- Check contains all and-ed simple tests generated so far or remains | |
2207 | -- unchanged in the case of detailed exception messaged. | |
2208 | ||
3b045963 | 2209 | ------------------------ |
2210 | -- May_Cause_Aliasing -- | |
2211 | ------------------------ | |
b73adb97 | 2212 | |
3b045963 | 2213 | function May_Cause_Aliasing |
4a9e7f0c | 2214 | (Formal_1 : Entity_Id; |
3b045963 | 2215 | Formal_2 : Entity_Id) return Boolean |
2216 | is | |
2217 | begin | |
2218 | -- The following combination cannot lead to aliasing | |
2219 | ||
2220 | -- Formal 1 Formal 2 | |
2221 | -- IN IN | |
2222 | ||
2223 | if Ekind (Formal_1) = E_In_Parameter | |
a45d946f | 2224 | and then |
2225 | Ekind (Formal_2) = E_In_Parameter | |
3b045963 | 2226 | then |
2227 | return False; | |
2228 | ||
2229 | -- The following combinations may lead to aliasing | |
2230 | ||
2231 | -- Formal 1 Formal 2 | |
2232 | -- IN OUT | |
2233 | -- IN IN OUT | |
2234 | -- OUT IN | |
2235 | -- OUT IN OUT | |
2236 | -- OUT OUT | |
2237 | ||
2238 | else | |
2239 | return True; | |
2240 | end if; | |
2241 | end May_Cause_Aliasing; | |
2242 | ||
2243 | --------------------- | |
2244 | -- Original_Actual -- | |
2245 | --------------------- | |
2246 | ||
2247 | function Original_Actual (N : Node_Id) return Node_Id is | |
2248 | begin | |
2249 | if Nkind (N) = N_Type_Conversion then | |
2250 | return Expression (N); | |
2251 | ||
2252 | -- The expander created a temporary to capture the result of a type | |
2253 | -- conversion where the expression is the real actual. | |
2254 | ||
2255 | elsif Nkind (N) = N_Identifier | |
2256 | and then Present (Original_Node (N)) | |
2257 | and then Nkind (Original_Node (N)) = N_Type_Conversion | |
2258 | then | |
2259 | return Expression (Original_Node (N)); | |
2260 | end if; | |
2261 | ||
2262 | return N; | |
2263 | end Original_Actual; | |
2264 | ||
bb569db0 | 2265 | ------------------- |
2266 | -- Overlap_Check -- | |
2267 | ------------------- | |
2268 | ||
2269 | procedure Overlap_Check | |
2270 | (Actual_1 : Node_Id; | |
2271 | Actual_2 : Node_Id; | |
2272 | Formal_1 : Entity_Id; | |
2273 | Formal_2 : Entity_Id; | |
2274 | Check : in out Node_Id) | |
2275 | is | |
29448168 | 2276 | Cond : Node_Id; |
2277 | ID_Casing : constant Casing_Type := | |
2278 | Identifier_Casing (Source_Index (Current_Sem_Unit)); | |
bb569db0 | 2279 | |
2280 | begin | |
2281 | -- Generate: | |
2282 | -- Actual_1'Overlaps_Storage (Actual_2) | |
2283 | ||
2284 | Cond := | |
2285 | Make_Attribute_Reference (Loc, | |
2286 | Prefix => New_Copy_Tree (Original_Actual (Actual_1)), | |
2287 | Attribute_Name => Name_Overlaps_Storage, | |
2288 | Expressions => | |
2289 | New_List (New_Copy_Tree (Original_Actual (Actual_2)))); | |
2290 | ||
2291 | -- Generate the following check when detailed exception messages are | |
2292 | -- enabled: | |
2293 | ||
2294 | -- if Actual_1'Overlaps_Storage (Actual_2) then | |
2295 | -- raise Program_Error with <detailed message>; | |
2296 | -- end if; | |
2297 | ||
2298 | if Exception_Extra_Info then | |
2299 | Start_String; | |
2300 | ||
2301 | -- Do not generate location information for internal calls | |
2302 | ||
2303 | if Comes_From_Source (Call) then | |
2304 | Store_String_Chars (Build_Location_String (Loc)); | |
2305 | Store_String_Char (' '); | |
2306 | end if; | |
2307 | ||
2308 | Store_String_Chars ("aliased parameters, actuals for """); | |
29448168 | 2309 | |
2310 | Get_Name_String (Chars (Formal_1)); | |
2311 | Set_Casing (ID_Casing); | |
2312 | Store_String_Chars (Name_Buffer (1 .. Name_Len)); | |
2313 | ||
bb569db0 | 2314 | Store_String_Chars (""" and """); |
29448168 | 2315 | |
2316 | Get_Name_String (Chars (Formal_2)); | |
2317 | Set_Casing (ID_Casing); | |
2318 | Store_String_Chars (Name_Buffer (1 .. Name_Len)); | |
2319 | ||
bb569db0 | 2320 | Store_String_Chars (""" overlap"); |
2321 | ||
2322 | Insert_Action (Call, | |
2323 | Make_If_Statement (Loc, | |
2324 | Condition => Cond, | |
2325 | Then_Statements => New_List ( | |
2326 | Make_Raise_Statement (Loc, | |
2327 | Name => | |
83c6c069 | 2328 | New_Occurrence_Of (Standard_Program_Error, Loc), |
bb569db0 | 2329 | Expression => Make_String_Literal (Loc, End_String))))); |
2330 | ||
2331 | -- Create a sequence of overlapping checks by and-ing them all | |
2332 | -- together. | |
2333 | ||
2334 | else | |
2335 | if No (Check) then | |
2336 | Check := Cond; | |
2337 | else | |
2338 | Check := | |
2339 | Make_And_Then (Loc, | |
2340 | Left_Opnd => Check, | |
2341 | Right_Opnd => Cond); | |
2342 | end if; | |
2343 | end if; | |
2344 | end Overlap_Check; | |
2345 | ||
3b045963 | 2346 | -- Local variables |
2347 | ||
15fca308 | 2348 | Actual_1 : Node_Id; |
2349 | Actual_2 : Node_Id; | |
2350 | Check : Node_Id; | |
2351 | Formal_1 : Entity_Id; | |
2352 | Formal_2 : Entity_Id; | |
2353 | Orig_Act_1 : Node_Id; | |
2354 | Orig_Act_2 : Node_Id; | |
3b045963 | 2355 | |
2356 | -- Start of processing for Apply_Parameter_Aliasing_Checks | |
2357 | ||
2358 | begin | |
bb569db0 | 2359 | Check := Empty; |
3b045963 | 2360 | |
2361 | Actual_1 := First_Actual (Call); | |
2362 | Formal_1 := First_Formal (Subp); | |
2363 | while Present (Actual_1) and then Present (Formal_1) loop | |
15fca308 | 2364 | Orig_Act_1 := Original_Actual (Actual_1); |
3b045963 | 2365 | |
2366 | -- Ensure that the actual is an object that is not passed by value. | |
2367 | -- Elementary types are always passed by value, therefore actuals of | |
747426db | 2368 | -- such types cannot lead to aliasing. An aggregate is an object in |
2369 | -- Ada 2012, but an actual that is an aggregate cannot overlap with | |
4dc3174c | 2370 | -- another actual. A type that is By_Reference (such as an array of |
2371 | -- controlled types) is not subject to the check because any update | |
2372 | -- will be done in place and a subsequent read will always see the | |
2373 | -- correct value, see RM 6.2 (12/3). | |
3b045963 | 2374 | |
15fca308 | 2375 | if Nkind (Orig_Act_1) = N_Aggregate |
2376 | or else (Nkind (Orig_Act_1) = N_Qualified_Expression | |
2377 | and then Nkind (Expression (Orig_Act_1)) = N_Aggregate) | |
747426db | 2378 | then |
2379 | null; | |
2380 | ||
15fca308 | 2381 | elsif Is_Object_Reference (Orig_Act_1) |
2382 | and then not Is_Elementary_Type (Etype (Orig_Act_1)) | |
2383 | and then not Is_By_Reference_Type (Etype (Orig_Act_1)) | |
3b045963 | 2384 | then |
2385 | Actual_2 := Next_Actual (Actual_1); | |
2386 | Formal_2 := Next_Formal (Formal_1); | |
2387 | while Present (Actual_2) and then Present (Formal_2) loop | |
15fca308 | 2388 | Orig_Act_2 := Original_Actual (Actual_2); |
3b045963 | 2389 | |
2390 | -- The other actual we are testing against must also denote | |
2391 | -- a non pass-by-value object. Generate the check only when | |
2392 | -- the mode of the two formals may lead to aliasing. | |
2393 | ||
15fca308 | 2394 | if Is_Object_Reference (Orig_Act_2) |
2395 | and then not Is_Elementary_Type (Etype (Orig_Act_2)) | |
3b045963 | 2396 | and then May_Cause_Aliasing (Formal_1, Formal_2) |
2397 | then | |
72f889fa | 2398 | Remove_Side_Effects (Actual_1); |
2399 | Remove_Side_Effects (Actual_2); | |
2400 | ||
bb569db0 | 2401 | Overlap_Check |
2402 | (Actual_1 => Actual_1, | |
2403 | Actual_2 => Actual_2, | |
2404 | Formal_1 => Formal_1, | |
2405 | Formal_2 => Formal_2, | |
2406 | Check => Check); | |
3b045963 | 2407 | end if; |
2408 | ||
2409 | Next_Actual (Actual_2); | |
2410 | Next_Formal (Formal_2); | |
2411 | end loop; | |
2412 | end if; | |
2413 | ||
2414 | Next_Actual (Actual_1); | |
2415 | Next_Formal (Formal_1); | |
2416 | end loop; | |
2417 | ||
bb569db0 | 2418 | -- Place a simple check right before the call |
3b045963 | 2419 | |
bb569db0 | 2420 | if Present (Check) and then not Exception_Extra_Info then |
3b045963 | 2421 | Insert_Action (Call, |
2422 | Make_Raise_Program_Error (Loc, | |
bb569db0 | 2423 | Condition => Check, |
2424 | Reason => PE_Aliased_Parameters)); | |
3b045963 | 2425 | end if; |
2426 | end Apply_Parameter_Aliasing_Checks; | |
2427 | ||
2428 | ------------------------------------- | |
2429 | -- Apply_Parameter_Validity_Checks -- | |
2430 | ------------------------------------- | |
2431 | ||
2432 | procedure Apply_Parameter_Validity_Checks (Subp : Entity_Id) is | |
2433 | Subp_Decl : Node_Id; | |
b73adb97 | 2434 | |
4a9e7f0c | 2435 | procedure Add_Validity_Check |
ed695684 | 2436 | (Formal : Entity_Id; |
2437 | Prag_Nam : Name_Id; | |
4a9e7f0c | 2438 | For_Result : Boolean := False); |
2439 | -- Add a single 'Valid[_Scalar] check which verifies the initialization | |
ed695684 | 2440 | -- of Formal. Prag_Nam denotes the pre or post condition pragma name. |
4a9e7f0c | 2441 | -- Set flag For_Result when to verify the result of a function. |
b73adb97 | 2442 | |
b73adb97 | 2443 | ------------------------ |
2444 | -- Add_Validity_Check -- | |
2445 | ------------------------ | |
2446 | ||
2447 | procedure Add_Validity_Check | |
ed695684 | 2448 | (Formal : Entity_Id; |
2449 | Prag_Nam : Name_Id; | |
b73adb97 | 2450 | For_Result : Boolean := False) |
2451 | is | |
ed695684 | 2452 | procedure Build_Pre_Post_Condition (Expr : Node_Id); |
2453 | -- Create a pre/postcondition pragma that tests expression Expr | |
2454 | ||
2455 | ------------------------------ | |
2456 | -- Build_Pre_Post_Condition -- | |
2457 | ------------------------------ | |
2458 | ||
2459 | procedure Build_Pre_Post_Condition (Expr : Node_Id) is | |
2460 | Loc : constant Source_Ptr := Sloc (Subp); | |
2461 | Decls : List_Id; | |
2462 | Prag : Node_Id; | |
2463 | ||
2464 | begin | |
2465 | Prag := | |
2466 | Make_Pragma (Loc, | |
c33cb5ff | 2467 | Chars => Prag_Nam, |
ed695684 | 2468 | Pragma_Argument_Associations => New_List ( |
2469 | Make_Pragma_Argument_Association (Loc, | |
2470 | Chars => Name_Check, | |
2471 | Expression => Expr))); | |
2472 | ||
2473 | -- Add a message unless exception messages are suppressed | |
2474 | ||
2475 | if not Exception_Locations_Suppressed then | |
2476 | Append_To (Pragma_Argument_Associations (Prag), | |
2477 | Make_Pragma_Argument_Association (Loc, | |
2478 | Chars => Name_Message, | |
2479 | Expression => | |
2480 | Make_String_Literal (Loc, | |
2481 | Strval => "failed " | |
2482 | & Get_Name_String (Prag_Nam) | |
2483 | & " from " | |
2484 | & Build_Location_String (Loc)))); | |
2485 | end if; | |
2486 | ||
2487 | -- Insert the pragma in the tree | |
2488 | ||
2489 | if Nkind (Parent (Subp_Decl)) = N_Compilation_Unit then | |
2490 | Add_Global_Declaration (Prag); | |
2491 | Analyze (Prag); | |
2492 | ||
2493 | -- PPC pragmas associated with subprogram bodies must be inserted | |
2494 | -- in the declarative part of the body. | |
2495 | ||
2496 | elsif Nkind (Subp_Decl) = N_Subprogram_Body then | |
2497 | Decls := Declarations (Subp_Decl); | |
2498 | ||
2499 | if No (Decls) then | |
2500 | Decls := New_List; | |
2501 | Set_Declarations (Subp_Decl, Decls); | |
2502 | end if; | |
2503 | ||
2504 | Prepend_To (Decls, Prag); | |
2505 | Analyze (Prag); | |
2506 | ||
2507 | -- For subprogram declarations insert the PPC pragma right after | |
2508 | -- the declarative node. | |
2509 | ||
2510 | else | |
2511 | Insert_After_And_Analyze (Subp_Decl, Prag); | |
2512 | end if; | |
2513 | end Build_Pre_Post_Condition; | |
2514 | ||
2515 | -- Local variables | |
2516 | ||
4a9e7f0c | 2517 | Loc : constant Source_Ptr := Sloc (Subp); |
ed695684 | 2518 | Typ : constant Entity_Id := Etype (Formal); |
b73adb97 | 2519 | Check : Node_Id; |
2520 | Nam : Name_Id; | |
2521 | ||
ed695684 | 2522 | -- Start of processing for Add_Validity_Check |
2523 | ||
b73adb97 | 2524 | begin |
9916a361 | 2525 | -- For scalars, generate 'Valid test |
b73adb97 | 2526 | |
2527 | if Is_Scalar_Type (Typ) then | |
2528 | Nam := Name_Valid; | |
9916a361 | 2529 | |
2530 | -- For any non-scalar with scalar parts, generate 'Valid_Scalars test | |
2531 | ||
2532 | elsif Scalar_Part_Present (Typ) then | |
b73adb97 | 2533 | Nam := Name_Valid_Scalars; |
9916a361 | 2534 | |
2535 | -- No test needed for other cases (no scalars to test) | |
2536 | ||
b73adb97 | 2537 | else |
2538 | return; | |
2539 | end if; | |
2540 | ||
2541 | -- Step 1: Create the expression to verify the validity of the | |
2542 | -- context. | |
2543 | ||
ed695684 | 2544 | Check := New_Occurrence_Of (Formal, Loc); |
b73adb97 | 2545 | |
2546 | -- When processing a function result, use 'Result. Generate | |
2547 | -- Context'Result | |
2548 | ||
2549 | if For_Result then | |
2550 | Check := | |
2551 | Make_Attribute_Reference (Loc, | |
2552 | Prefix => Check, | |
2553 | Attribute_Name => Name_Result); | |
2554 | end if; | |
2555 | ||
2556 | -- Generate: | |
2557 | -- Context['Result]'Valid[_Scalars] | |
2558 | ||
2559 | Check := | |
2560 | Make_Attribute_Reference (Loc, | |
2561 | Prefix => Check, | |
2562 | Attribute_Name => Nam); | |
2563 | ||
4a9e7f0c | 2564 | -- Step 2: Create a pre or post condition pragma |
2565 | ||
ed695684 | 2566 | Build_Pre_Post_Condition (Check); |
4a9e7f0c | 2567 | end Add_Validity_Check; |
2568 | ||
4a9e7f0c | 2569 | -- Local variables |
2570 | ||
2571 | Formal : Entity_Id; | |
4a9e7f0c | 2572 | Subp_Spec : Node_Id; |
2573 | ||
3b045963 | 2574 | -- Start of processing for Apply_Parameter_Validity_Checks |
b73adb97 | 2575 | |
2576 | begin | |
4a9e7f0c | 2577 | -- Extract the subprogram specification and declaration nodes |
b73adb97 | 2578 | |
4a9e7f0c | 2579 | Subp_Spec := Parent (Subp); |
a45d946f | 2580 | |
4a9e7f0c | 2581 | if Nkind (Subp_Spec) = N_Defining_Program_Unit_Name then |
2582 | Subp_Spec := Parent (Subp_Spec); | |
2583 | end if; | |
a45d946f | 2584 | |
4a9e7f0c | 2585 | Subp_Decl := Parent (Subp_Spec); |
9e58d7ed | 2586 | |
b73adb97 | 2587 | if not Comes_From_Source (Subp) |
4a9e7f0c | 2588 | |
2589 | -- Do not process formal subprograms because the corresponding actual | |
2590 | -- will receive the proper checks when the instance is analyzed. | |
2591 | ||
2592 | or else Is_Formal_Subprogram (Subp) | |
2593 | ||
95ac2d90 | 2594 | -- Do not process imported subprograms since pre and postconditions |
a45d946f | 2595 | -- are never verified on routines coming from a different language. |
4a9e7f0c | 2596 | |
b73adb97 | 2597 | or else Is_Imported (Subp) |
2598 | or else Is_Intrinsic_Subprogram (Subp) | |
4a9e7f0c | 2599 | |
a45d946f | 2600 | -- The PPC pragmas generated by this routine do not correspond to |
2601 | -- source aspects, therefore they cannot be applied to abstract | |
2602 | -- subprograms. | |
4a9e7f0c | 2603 | |
7c443ae8 | 2604 | or else Nkind (Subp_Decl) = N_Abstract_Subprogram_Declaration |
4a9e7f0c | 2605 | |
a45d946f | 2606 | -- Do not consider subprogram renaminds because the renamed entity |
2607 | -- already has the proper PPC pragmas. | |
1bd93de5 | 2608 | |
2609 | or else Nkind (Subp_Decl) = N_Subprogram_Renaming_Declaration | |
2610 | ||
a45d946f | 2611 | -- Do not process null procedures because there is no benefit of |
2612 | -- adding the checks to a no action routine. | |
4a9e7f0c | 2613 | |
2614 | or else (Nkind (Subp_Spec) = N_Procedure_Specification | |
a45d946f | 2615 | and then Null_Present (Subp_Spec)) |
b73adb97 | 2616 | then |
2617 | return; | |
2618 | end if; | |
2619 | ||
4a9e7f0c | 2620 | -- Inspect all the formals applying aliasing and scalar initialization |
2621 | -- checks where applicable. | |
b73adb97 | 2622 | |
2623 | Formal := First_Formal (Subp); | |
2624 | while Present (Formal) loop | |
4a9e7f0c | 2625 | |
2626 | -- Generate the following scalar initialization checks for each | |
2627 | -- formal parameter: | |
2628 | ||
2629 | -- mode IN - Pre => Formal'Valid[_Scalars] | |
2630 | -- mode IN OUT - Pre, Post => Formal'Valid[_Scalars] | |
2631 | -- mode OUT - Post => Formal'Valid[_Scalars] | |
2632 | ||
2633 | if Check_Validity_Of_Parameters then | |
2634 | if Ekind_In (Formal, E_In_Parameter, E_In_Out_Parameter) then | |
2635 | Add_Validity_Check (Formal, Name_Precondition, False); | |
2636 | end if; | |
2637 | ||
2638 | if Ekind_In (Formal, E_In_Out_Parameter, E_Out_Parameter) then | |
2639 | Add_Validity_Check (Formal, Name_Postcondition, False); | |
2640 | end if; | |
b73adb97 | 2641 | end if; |
2642 | ||
b73adb97 | 2643 | Next_Formal (Formal); |
2644 | end loop; | |
2645 | ||
a45d946f | 2646 | -- Generate following scalar initialization check for function result: |
4a9e7f0c | 2647 | |
2648 | -- Post => Subp'Result'Valid[_Scalars] | |
b73adb97 | 2649 | |
a45d946f | 2650 | if Check_Validity_Of_Parameters and then Ekind (Subp) = E_Function then |
4a9e7f0c | 2651 | Add_Validity_Check (Subp, Name_Postcondition, True); |
b73adb97 | 2652 | end if; |
3b045963 | 2653 | end Apply_Parameter_Validity_Checks; |
b73adb97 | 2654 | |
7aafae1c | 2655 | --------------------------- |
2656 | -- Apply_Predicate_Check -- | |
2657 | --------------------------- | |
2658 | ||
e60047e5 | 2659 | procedure Apply_Predicate_Check |
2660 | (N : Node_Id; | |
2661 | Typ : Entity_Id; | |
2662 | Fun : Entity_Id := Empty) | |
2663 | is | |
301d5ec3 | 2664 | S : Entity_Id; |
9e58d7ed | 2665 | |
7aafae1c | 2666 | begin |
da2270e7 | 2667 | if Predicate_Checks_Suppressed (Empty) then |
2668 | return; | |
301d5ec3 | 2669 | |
2c011bc5 | 2670 | elsif Predicates_Ignored (Typ) then |
2671 | return; | |
2672 | ||
da2270e7 | 2673 | elsif Present (Predicate_Function (Typ)) then |
301d5ec3 | 2674 | S := Current_Scope; |
9e58d7ed | 2675 | while Present (S) and then not Is_Subprogram (S) loop |
301d5ec3 | 2676 | S := Scope (S); |
2677 | end loop; | |
2678 | ||
ea822fd4 | 2679 | -- A predicate check does not apply within internally generated |
2680 | -- subprograms, such as TSS functions. | |
2681 | ||
2682 | if Within_Internal_Subprogram then | |
301d5ec3 | 2683 | return; |
22631b41 | 2684 | |
96a2d100 | 2685 | -- If the check appears within the predicate function itself, it |
2686 | -- means that the user specified a check whose formal is the | |
2687 | -- predicated subtype itself, rather than some covering type. This | |
2688 | -- is likely to be a common error, and thus deserves a warning. | |
22631b41 | 2689 | |
0e9014a7 | 2690 | elsif Present (S) and then S = Predicate_Function (Typ) then |
e60047e5 | 2691 | Error_Msg_NE |
0c4abd51 | 2692 | ("predicate check includes a call to& that requires a " |
2693 | & "predicate check??", Parent (N), Fun); | |
96a2d100 | 2694 | Error_Msg_N |
cb97ae5c | 2695 | ("\this will result in infinite recursion??", Parent (N)); |
e60047e5 | 2696 | |
2697 | if Is_First_Subtype (Typ) then | |
2698 | Error_Msg_NE | |
0c4abd51 | 2699 | ("\use an explicit subtype of& to carry the predicate", |
e60047e5 | 2700 | Parent (N), Typ); |
2701 | end if; | |
2702 | ||
96a2d100 | 2703 | Insert_Action (N, |
61016a7a | 2704 | Make_Raise_Storage_Error (Sloc (N), |
2705 | Reason => SE_Infinite_Recursion)); | |
22631b41 | 2706 | |
64cc9e5d | 2707 | -- Here for normal case of predicate active |
e6281d47 | 2708 | |
61016a7a | 2709 | else |
b04165c4 | 2710 | -- If the type has a static predicate and the expression is known |
2711 | -- at compile time, see if the expression satisfies the predicate. | |
3a75f20b | 2712 | |
2713 | Check_Expression_Against_Static_Predicate (N, Typ); | |
e6281d47 | 2714 | |
e34cd69d | 2715 | if not Expander_Active then |
2716 | return; | |
2717 | end if; | |
2718 | ||
2719 | -- For an entity of the type, generate a call to the predicate | |
2720 | -- function, unless its type is an actual subtype, which is not | |
2721 | -- visible outside of the enclosing subprogram. | |
2722 | ||
2723 | if Is_Entity_Name (N) | |
2724 | and then not Is_Actual_Subtype (Typ) | |
2725 | then | |
da2270e7 | 2726 | Insert_Action (N, |
2727 | Make_Predicate_Check | |
2728 | (Typ, New_Occurrence_Of (Entity (N), Sloc (N)))); | |
2729 | ||
f9906591 | 2730 | -- If the expression is not an entity it may have side effects, |
bc885df9 | 2731 | -- and the following call will create an object declaration for |
2732 | -- it. We disable checks during its analysis, to prevent an | |
2733 | -- infinite recursion. | |
da2270e7 | 2734 | |
e3b910d8 | 2735 | -- If the prefix is an aggregate in an assignment, apply the |
2736 | -- check to the LHS after assignment, rather than create a | |
2737 | -- redundant temporary. This is only necessary in rare cases | |
2738 | -- of array types (including strings) initialized with an | |
2739 | -- aggregate with an "others" clause, either coming from source | |
2740 | -- or generated by an Initialize_Scalars pragma. | |
2741 | ||
2742 | elsif Nkind (N) = N_Aggregate | |
2743 | and then Nkind (Parent (N)) = N_Assignment_Statement | |
2744 | then | |
2745 | Insert_Action_After (Parent (N), | |
2746 | Make_Predicate_Check | |
2747 | (Typ, Duplicate_Subexpr (Name (Parent (N))))); | |
2748 | ||
da2270e7 | 2749 | else |
2750 | Insert_Action (N, | |
bc885df9 | 2751 | Make_Predicate_Check |
2752 | (Typ, Duplicate_Subexpr (N)), Suppress => All_Checks); | |
da2270e7 | 2753 | end if; |
301d5ec3 | 2754 | end if; |
7aafae1c | 2755 | end if; |
2756 | end Apply_Predicate_Check; | |
2757 | ||
ee6ba406 | 2758 | ----------------------- |
2759 | -- Apply_Range_Check -- | |
2760 | ----------------------- | |
2761 | ||
2762 | procedure Apply_Range_Check | |
2763 | (Ck_Node : Node_Id; | |
2764 | Target_Typ : Entity_Id; | |
2765 | Source_Typ : Entity_Id := Empty) | |
2766 | is | |
2767 | begin | |
2768 | Apply_Selected_Range_Checks | |
2769 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
2770 | end Apply_Range_Check; | |
2771 | ||
2772 | ------------------------------ | |
2773 | -- Apply_Scalar_Range_Check -- | |
2774 | ------------------------------ | |
2775 | ||
feff2f05 | 2776 | -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag |
2777 | -- off if it is already set on. | |
ee6ba406 | 2778 | |
2779 | procedure Apply_Scalar_Range_Check | |
2780 | (Expr : Node_Id; | |
2781 | Target_Typ : Entity_Id; | |
2782 | Source_Typ : Entity_Id := Empty; | |
2783 | Fixed_Int : Boolean := False) | |
2784 | is | |
2785 | Parnt : constant Node_Id := Parent (Expr); | |
2786 | S_Typ : Entity_Id; | |
2787 | Arr : Node_Id := Empty; -- initialize to prevent warning | |
2788 | Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning | |
ee6ba406 | 2789 | |
2790 | Is_Subscr_Ref : Boolean; | |
2791 | -- Set true if Expr is a subscript | |
2792 | ||
2793 | Is_Unconstrained_Subscr_Ref : Boolean; | |
2794 | -- Set true if Expr is a subscript of an unconstrained array. In this | |
2795 | -- case we do not attempt to do an analysis of the value against the | |
2796 | -- range of the subscript, since we don't know the actual subtype. | |
2797 | ||
2798 | Int_Real : Boolean; | |
feff2f05 | 2799 | -- Set to True if Expr should be regarded as a real value even though |
2800 | -- the type of Expr might be discrete. | |
ee6ba406 | 2801 | |
a0a15971 | 2802 | procedure Bad_Value (Warn : Boolean := False); |
2803 | -- Procedure called if value is determined to be out of range. Warn is | |
2804 | -- True to force a warning instead of an error, even when SPARK_Mode is | |
2805 | -- On. | |
ee6ba406 | 2806 | |
9dfe12ae | 2807 | --------------- |
2808 | -- Bad_Value -- | |
2809 | --------------- | |
2810 | ||
a0a15971 | 2811 | procedure Bad_Value (Warn : Boolean := False) is |
ee6ba406 | 2812 | begin |
2813 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 2814 | (Expr, "value not in range of}??", CE_Range_Check_Failed, |
a0a15971 | 2815 | Ent => Target_Typ, |
2816 | Typ => Target_Typ, | |
2817 | Warn => Warn); | |
ee6ba406 | 2818 | end Bad_Value; |
2819 | ||
9dfe12ae | 2820 | -- Start of processing for Apply_Scalar_Range_Check |
2821 | ||
ee6ba406 | 2822 | begin |
2af58f67 | 2823 | -- Return if check obviously not needed |
ee6ba406 | 2824 | |
2af58f67 | 2825 | if |
2826 | -- Not needed inside generic | |
ee6ba406 | 2827 | |
2af58f67 | 2828 | Inside_A_Generic |
2829 | ||
2830 | -- Not needed if previous error | |
2831 | ||
2832 | or else Target_Typ = Any_Type | |
2833 | or else Nkind (Expr) = N_Error | |
2834 | ||
2835 | -- Not needed for non-scalar type | |
2836 | ||
2837 | or else not Is_Scalar_Type (Target_Typ) | |
2838 | ||
2839 | -- Not needed if we know node raises CE already | |
2840 | ||
2841 | or else Raises_Constraint_Error (Expr) | |
ee6ba406 | 2842 | then |
2843 | return; | |
2844 | end if; | |
2845 | ||
2846 | -- Now, see if checks are suppressed | |
2847 | ||
2848 | Is_Subscr_Ref := | |
2849 | Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component; | |
2850 | ||
2851 | if Is_Subscr_Ref then | |
2852 | Arr := Prefix (Parnt); | |
2853 | Arr_Typ := Get_Actual_Subtype_If_Available (Arr); | |
cce84b09 | 2854 | |
a3a76ccc | 2855 | if Is_Access_Type (Arr_Typ) then |
245e87df | 2856 | Arr_Typ := Designated_Type (Arr_Typ); |
a3a76ccc | 2857 | end if; |
ee6ba406 | 2858 | end if; |
2859 | ||
2860 | if not Do_Range_Check (Expr) then | |
2861 | ||
2862 | -- Subscript reference. Check for Index_Checks suppressed | |
2863 | ||
2864 | if Is_Subscr_Ref then | |
2865 | ||
2866 | -- Check array type and its base type | |
2867 | ||
2868 | if Index_Checks_Suppressed (Arr_Typ) | |
9dfe12ae | 2869 | or else Index_Checks_Suppressed (Base_Type (Arr_Typ)) |
ee6ba406 | 2870 | then |
2871 | return; | |
2872 | ||
2873 | -- Check array itself if it is an entity name | |
2874 | ||
2875 | elsif Is_Entity_Name (Arr) | |
9dfe12ae | 2876 | and then Index_Checks_Suppressed (Entity (Arr)) |
ee6ba406 | 2877 | then |
2878 | return; | |
2879 | ||
2880 | -- Check expression itself if it is an entity name | |
2881 | ||
2882 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 2883 | and then Index_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 2884 | then |
2885 | return; | |
2886 | end if; | |
2887 | ||
2888 | -- All other cases, check for Range_Checks suppressed | |
2889 | ||
2890 | else | |
2891 | -- Check target type and its base type | |
2892 | ||
2893 | if Range_Checks_Suppressed (Target_Typ) | |
9dfe12ae | 2894 | or else Range_Checks_Suppressed (Base_Type (Target_Typ)) |
ee6ba406 | 2895 | then |
2896 | return; | |
2897 | ||
2898 | -- Check expression itself if it is an entity name | |
2899 | ||
2900 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 2901 | and then Range_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 2902 | then |
2903 | return; | |
2904 | ||
feff2f05 | 2905 | -- If Expr is part of an assignment statement, then check left |
2906 | -- side of assignment if it is an entity name. | |
ee6ba406 | 2907 | |
2908 | elsif Nkind (Parnt) = N_Assignment_Statement | |
2909 | and then Is_Entity_Name (Name (Parnt)) | |
9dfe12ae | 2910 | and then Range_Checks_Suppressed (Entity (Name (Parnt))) |
ee6ba406 | 2911 | then |
2912 | return; | |
2913 | end if; | |
2914 | end if; | |
2915 | end if; | |
2916 | ||
9dfe12ae | 2917 | -- Do not set range checks if they are killed |
2918 | ||
2919 | if Nkind (Expr) = N_Unchecked_Type_Conversion | |
2920 | and then Kill_Range_Check (Expr) | |
2921 | then | |
2922 | return; | |
2923 | end if; | |
2924 | ||
2925 | -- Do not set range checks for any values from System.Scalar_Values | |
39a0c1d3 | 2926 | -- since the whole idea of such values is to avoid checking them. |
9dfe12ae | 2927 | |
2928 | if Is_Entity_Name (Expr) | |
2929 | and then Is_RTU (Scope (Entity (Expr)), System_Scalar_Values) | |
2930 | then | |
2931 | return; | |
2932 | end if; | |
2933 | ||
ee6ba406 | 2934 | -- Now see if we need a check |
2935 | ||
2936 | if No (Source_Typ) then | |
2937 | S_Typ := Etype (Expr); | |
2938 | else | |
2939 | S_Typ := Source_Typ; | |
2940 | end if; | |
2941 | ||
2942 | if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then | |
2943 | return; | |
2944 | end if; | |
2945 | ||
2946 | Is_Unconstrained_Subscr_Ref := | |
2947 | Is_Subscr_Ref and then not Is_Constrained (Arr_Typ); | |
2948 | ||
b40670e1 | 2949 | -- Special checks for floating-point type |
ee6ba406 | 2950 | |
b40670e1 | 2951 | if Is_Floating_Point_Type (S_Typ) then |
2952 | ||
2953 | -- Always do a range check if the source type includes infinities and | |
2954 | -- the target type does not include infinities. We do not do this if | |
2955 | -- range checks are killed. | |
cb388b10 | 2956 | -- If the expression is a literal and the bounds of the type are |
2957 | -- static constants it may be possible to optimize the check. | |
b40670e1 | 2958 | |
2959 | if Has_Infinities (S_Typ) | |
2960 | and then not Has_Infinities (Target_Typ) | |
2961 | then | |
cb388b10 | 2962 | -- If the expression is a literal and the bounds of the type are |
2963 | -- static constants it may be possible to optimize the check. | |
2964 | ||
2965 | if Nkind (Expr) = N_Real_Literal then | |
2966 | declare | |
2967 | Tlo : constant Node_Id := Type_Low_Bound (Target_Typ); | |
2968 | Thi : constant Node_Id := Type_High_Bound (Target_Typ); | |
2969 | ||
2970 | begin | |
2971 | if Compile_Time_Known_Value (Tlo) | |
2972 | and then Compile_Time_Known_Value (Thi) | |
2973 | and then Expr_Value_R (Expr) >= Expr_Value_R (Tlo) | |
2974 | and then Expr_Value_R (Expr) <= Expr_Value_R (Thi) | |
2975 | then | |
2976 | return; | |
2977 | else | |
2978 | Enable_Range_Check (Expr); | |
2979 | end if; | |
2980 | end; | |
2981 | ||
2982 | else | |
2983 | Enable_Range_Check (Expr); | |
2984 | end if; | |
b40670e1 | 2985 | end if; |
ee6ba406 | 2986 | end if; |
2987 | ||
feff2f05 | 2988 | -- Return if we know expression is definitely in the range of the target |
2989 | -- type as determined by Determine_Range. Right now we only do this for | |
2990 | -- discrete types, and not fixed-point or floating-point types. | |
ee6ba406 | 2991 | |
f2a06be9 | 2992 | -- The additional less-precise tests below catch these cases |
ee6ba406 | 2993 | |
54022749 | 2994 | -- In GNATprove_Mode, also deal with the case of a conversion from |
2995 | -- floating-point to integer. It is only possible because analysis | |
2996 | -- in GNATprove rules out the possibility of a NaN or infinite value. | |
2997 | ||
feff2f05 | 2998 | -- Note: skip this if we are given a source_typ, since the point of |
2999 | -- supplying a Source_Typ is to stop us looking at the expression. | |
3000 | -- We could sharpen this test to be out parameters only ??? | |
ee6ba406 | 3001 | |
3002 | if Is_Discrete_Type (Target_Typ) | |
54022749 | 3003 | and then (Is_Discrete_Type (Etype (Expr)) |
3004 | or else (GNATprove_Mode | |
3005 | and then Is_Floating_Point_Type (Etype (Expr)))) | |
ee6ba406 | 3006 | and then not Is_Unconstrained_Subscr_Ref |
3007 | and then No (Source_Typ) | |
3008 | then | |
3009 | declare | |
ee6ba406 | 3010 | Thi : constant Node_Id := Type_High_Bound (Target_Typ); |
552d7cbc | 3011 | Tlo : constant Node_Id := Type_Low_Bound (Target_Typ); |
ee6ba406 | 3012 | |
3013 | begin | |
3014 | if Compile_Time_Known_Value (Tlo) | |
3015 | and then Compile_Time_Known_Value (Thi) | |
3016 | then | |
9dfe12ae | 3017 | declare |
5bb74b99 | 3018 | OK : Boolean := False; -- initialize to prevent warning |
9dfe12ae | 3019 | Hiv : constant Uint := Expr_Value (Thi); |
552d7cbc | 3020 | Lov : constant Uint := Expr_Value (Tlo); |
5bb74b99 | 3021 | Hi : Uint := No_Uint; |
3022 | Lo : Uint := No_Uint; | |
ee6ba406 | 3023 | |
9dfe12ae | 3024 | begin |
552d7cbc | 3025 | -- If range is null, we for sure have a constraint error (we |
3026 | -- don't even need to look at the value involved, since all | |
3027 | -- possible values will raise CE). | |
9dfe12ae | 3028 | |
3029 | if Lov > Hiv then | |
f4f2bf51 | 3030 | |
a0a15971 | 3031 | -- When SPARK_Mode is On, force a warning instead of |
3032 | -- an error in that case, as this likely corresponds | |
3033 | -- to deactivated code. | |
3034 | ||
3035 | Bad_Value (Warn => SPARK_Mode = On); | |
3036 | ||
3037 | -- In GNATprove mode, we enable the range check so that | |
3038 | -- GNATprove will issue a message if it cannot be proved. | |
f4f2bf51 | 3039 | |
3040 | if GNATprove_Mode then | |
3041 | Enable_Range_Check (Expr); | |
f4f2bf51 | 3042 | end if; |
3043 | ||
9dfe12ae | 3044 | return; |
3045 | end if; | |
3046 | ||
3047 | -- Otherwise determine range of value | |
3048 | ||
54022749 | 3049 | if Is_Discrete_Type (Etype (Expr)) then |
552d7cbc | 3050 | Determine_Range |
3051 | (Expr, OK, Lo, Hi, Assume_Valid => True); | |
54022749 | 3052 | |
3053 | -- When converting a float to an integer type, determine the | |
3054 | -- range in real first, and then convert the bounds using | |
3055 | -- UR_To_Uint which correctly rounds away from zero when | |
3056 | -- half way between two integers, as required by normal | |
3057 | -- Ada 95 rounding semantics. It is only possible because | |
3058 | -- analysis in GNATprove rules out the possibility of a NaN | |
3059 | -- or infinite value. | |
3060 | ||
3061 | elsif GNATprove_Mode | |
3062 | and then Is_Floating_Point_Type (Etype (Expr)) | |
3063 | then | |
3064 | declare | |
54022749 | 3065 | Hir : Ureal; |
552d7cbc | 3066 | Lor : Ureal; |
3067 | ||
54022749 | 3068 | begin |
552d7cbc | 3069 | Determine_Range_R |
3070 | (Expr, OK, Lor, Hir, Assume_Valid => True); | |
54022749 | 3071 | |
3072 | if OK then | |
3073 | Lo := UR_To_Uint (Lor); | |
3074 | Hi := UR_To_Uint (Hir); | |
3075 | end if; | |
3076 | end; | |
3077 | end if; | |
9dfe12ae | 3078 | |
3079 | if OK then | |
3080 | ||
3081 | -- If definitely in range, all OK | |
ee6ba406 | 3082 | |
ee6ba406 | 3083 | if Lo >= Lov and then Hi <= Hiv then |
3084 | return; | |
3085 | ||
9dfe12ae | 3086 | -- If definitely not in range, warn |
3087 | ||
ee6ba406 | 3088 | elsif Lov > Hi or else Hiv < Lo then |
e9dae6c3 | 3089 | |
c59854a0 | 3090 | -- Ignore out of range values for System.Priority in |
3091 | -- CodePeer mode since the actual target compiler may | |
3092 | -- provide a wider range. | |
3093 | ||
3094 | if not CodePeer_Mode | |
3095 | or else Target_Typ /= RTE (RE_Priority) | |
3096 | then | |
3097 | Bad_Value; | |
3098 | end if; | |
3099 | ||
ee6ba406 | 3100 | return; |
9dfe12ae | 3101 | |
3102 | -- Otherwise we don't know | |
3103 | ||
3104 | else | |
3105 | null; | |
ee6ba406 | 3106 | end if; |
9dfe12ae | 3107 | end if; |
3108 | end; | |
ee6ba406 | 3109 | end if; |
3110 | end; | |
3111 | end if; | |
3112 | ||
3113 | Int_Real := | |
3114 | Is_Floating_Point_Type (S_Typ) | |
3115 | or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int); | |
3116 | ||
3117 | -- Check if we can determine at compile time whether Expr is in the | |
9dfe12ae | 3118 | -- range of the target type. Note that if S_Typ is within the bounds |
3119 | -- of Target_Typ then this must be the case. This check is meaningful | |
3120 | -- only if this is not a conversion between integer and real types. | |
ee6ba406 | 3121 | |
3122 | if not Is_Unconstrained_Subscr_Ref | |
b40670e1 | 3123 | and then Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ) |
ee6ba406 | 3124 | and then |
7a1dabb3 | 3125 | (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int) |
ac5f5168 | 3126 | |
3127 | -- Also check if the expression itself is in the range of the | |
3128 | -- target type if it is a known at compile time value. We skip | |
3129 | -- this test if S_Typ is set since for OUT and IN OUT parameters | |
3130 | -- the Expr itself is not relevant to the checking. | |
3131 | ||
ee6ba406 | 3132 | or else |
ac5f5168 | 3133 | (No (Source_Typ) |
3134 | and then Is_In_Range (Expr, Target_Typ, | |
3135 | Assume_Valid => True, | |
3136 | Fixed_Int => Fixed_Int, | |
3137 | Int_Real => Int_Real))) | |
ee6ba406 | 3138 | then |
3139 | return; | |
3140 | ||
9c486805 | 3141 | elsif Is_Out_Of_Range (Expr, Target_Typ, |
3142 | Assume_Valid => True, | |
3143 | Fixed_Int => Fixed_Int, | |
3144 | Int_Real => Int_Real) | |
3145 | then | |
ee6ba406 | 3146 | Bad_Value; |
3147 | return; | |
3148 | ||
b40670e1 | 3149 | -- Floating-point case |
feff2f05 | 3150 | -- In the floating-point case, we only do range checks if the type is |
3151 | -- constrained. We definitely do NOT want range checks for unconstrained | |
29d958a7 | 3152 | -- types, since we want to have infinities, except when |
3153 | -- Check_Float_Overflow is set. | |
ee6ba406 | 3154 | |
9dfe12ae | 3155 | elsif Is_Floating_Point_Type (S_Typ) then |
29d958a7 | 3156 | if Is_Constrained (S_Typ) or else Check_Float_Overflow then |
9dfe12ae | 3157 | Enable_Range_Check (Expr); |
3158 | end if; | |
ee6ba406 | 3159 | |
9dfe12ae | 3160 | -- For all other cases we enable a range check unconditionally |
ee6ba406 | 3161 | |
3162 | else | |
3163 | Enable_Range_Check (Expr); | |
3164 | return; | |
3165 | end if; | |
ee6ba406 | 3166 | end Apply_Scalar_Range_Check; |
3167 | ||
3168 | ---------------------------------- | |
3169 | -- Apply_Selected_Length_Checks -- | |
3170 | ---------------------------------- | |
3171 | ||
3172 | procedure Apply_Selected_Length_Checks | |
3173 | (Ck_Node : Node_Id; | |
3174 | Target_Typ : Entity_Id; | |
3175 | Source_Typ : Entity_Id; | |
3176 | Do_Static : Boolean) | |
3177 | is | |
2b4f2458 | 3178 | Checks_On : constant Boolean := |
3179 | not Index_Checks_Suppressed (Target_Typ) | |
3180 | or else | |
3181 | not Length_Checks_Suppressed (Target_Typ); | |
3182 | ||
3183 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
3184 | ||
ee6ba406 | 3185 | Cond : Node_Id; |
ee6ba406 | 3186 | R_Cno : Node_Id; |
2b4f2458 | 3187 | R_Result : Check_Result; |
ee6ba406 | 3188 | |
3189 | begin | |
18cb6d78 | 3190 | -- Only apply checks when generating code |
f0d65dae | 3191 | |
4098232e | 3192 | -- Note: this means that we lose some useful warnings if the expander |
f0d65dae | 3193 | -- is not active. |
4098232e | 3194 | |
18cb6d78 | 3195 | if not Expander_Active then |
ee6ba406 | 3196 | return; |
3197 | end if; | |
3198 | ||
3199 | R_Result := | |
3200 | Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
3201 | ||
3202 | for J in 1 .. 2 loop | |
ee6ba406 | 3203 | R_Cno := R_Result (J); |
3204 | exit when No (R_Cno); | |
3205 | ||
3206 | -- A length check may mention an Itype which is attached to a | |
3207 | -- subsequent node. At the top level in a package this can cause | |
3208 | -- an order-of-elaboration problem, so we make sure that the itype | |
3209 | -- is referenced now. | |
3210 | ||
3211 | if Ekind (Current_Scope) = E_Package | |
3212 | and then Is_Compilation_Unit (Current_Scope) | |
3213 | then | |
3214 | Ensure_Defined (Target_Typ, Ck_Node); | |
3215 | ||
3216 | if Present (Source_Typ) then | |
3217 | Ensure_Defined (Source_Typ, Ck_Node); | |
3218 | ||
3219 | elsif Is_Itype (Etype (Ck_Node)) then | |
3220 | Ensure_Defined (Etype (Ck_Node), Ck_Node); | |
3221 | end if; | |
3222 | end if; | |
3223 | ||
feff2f05 | 3224 | -- If the item is a conditional raise of constraint error, then have |
3225 | -- a look at what check is being performed and ??? | |
ee6ba406 | 3226 | |
3227 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
3228 | and then Present (Condition (R_Cno)) | |
3229 | then | |
3230 | Cond := Condition (R_Cno); | |
3231 | ||
0577b0b1 | 3232 | -- Case where node does not now have a dynamic check |
ee6ba406 | 3233 | |
0577b0b1 | 3234 | if not Has_Dynamic_Length_Check (Ck_Node) then |
3235 | ||
3236 | -- If checks are on, just insert the check | |
3237 | ||
3238 | if Checks_On then | |
3239 | Insert_Action (Ck_Node, R_Cno); | |
3240 | ||
3241 | if not Do_Static then | |
3242 | Set_Has_Dynamic_Length_Check (Ck_Node); | |
3243 | end if; | |
3244 | ||
3245 | -- If checks are off, then analyze the length check after | |
3246 | -- temporarily attaching it to the tree in case the relevant | |
6fb3c314 | 3247 | -- condition can be evaluated at compile time. We still want a |
0577b0b1 | 3248 | -- compile time warning in this case. |
3249 | ||
3250 | else | |
3251 | Set_Parent (R_Cno, Ck_Node); | |
3252 | Analyze (R_Cno); | |
ee6ba406 | 3253 | end if; |
ee6ba406 | 3254 | end if; |
3255 | ||
3256 | -- Output a warning if the condition is known to be True | |
3257 | ||
3258 | if Is_Entity_Name (Cond) | |
3259 | and then Entity (Cond) = Standard_True | |
3260 | then | |
3261 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 3262 | (Ck_Node, "wrong length for array of}??", |
f15731c4 | 3263 | CE_Length_Check_Failed, |
ee6ba406 | 3264 | Ent => Target_Typ, |
3265 | Typ => Target_Typ); | |
3266 | ||
3267 | -- If we were only doing a static check, or if checks are not | |
3268 | -- on, then we want to delete the check, since it is not needed. | |
3269 | -- We do this by replacing the if statement by a null statement | |
3270 | ||
3271 | elsif Do_Static or else not Checks_On then | |
00c403ee | 3272 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 3273 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
3274 | end if; | |
3275 | ||
3276 | else | |
3277 | Install_Static_Check (R_Cno, Loc); | |
3278 | end if; | |
ee6ba406 | 3279 | end loop; |
ee6ba406 | 3280 | end Apply_Selected_Length_Checks; |
3281 | ||
3282 | --------------------------------- | |
3283 | -- Apply_Selected_Range_Checks -- | |
3284 | --------------------------------- | |
3285 | ||
3286 | procedure Apply_Selected_Range_Checks | |
3287 | (Ck_Node : Node_Id; | |
3288 | Target_Typ : Entity_Id; | |
3289 | Source_Typ : Entity_Id; | |
3290 | Do_Static : Boolean) | |
3291 | is | |
ee6ba406 | 3292 | Checks_On : constant Boolean := |
f9bcba0d | 3293 | not Index_Checks_Suppressed (Target_Typ) |
5372d110 | 3294 | or else |
3295 | not Range_Checks_Suppressed (Target_Typ); | |
f9bcba0d | 3296 | |
2b4f2458 | 3297 | Loc : constant Source_Ptr := Sloc (Ck_Node); |
3298 | ||
f9bcba0d | 3299 | Cond : Node_Id; |
3300 | R_Cno : Node_Id; | |
3301 | R_Result : Check_Result; | |
ee6ba406 | 3302 | |
3303 | begin | |
f0d65dae | 3304 | -- Only apply checks when generating code. In GNATprove mode, we do not |
3305 | -- apply the checks, but we still call Selected_Range_Checks to possibly | |
3306 | -- issue errors on SPARK code when a run-time error can be detected at | |
3307 | -- compile time. | |
3308 | ||
3309 | if not GNATprove_Mode then | |
3310 | if not Expander_Active or not Checks_On then | |
3311 | return; | |
3312 | end if; | |
ee6ba406 | 3313 | end if; |
3314 | ||
3315 | R_Result := | |
3316 | Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
3317 | ||
f0d65dae | 3318 | if GNATprove_Mode then |
3319 | return; | |
3320 | end if; | |
3321 | ||
ee6ba406 | 3322 | for J in 1 .. 2 loop |
ee6ba406 | 3323 | R_Cno := R_Result (J); |
3324 | exit when No (R_Cno); | |
3325 | ||
f9bcba0d | 3326 | -- The range check requires runtime evaluation. Depending on what its |
3327 | -- triggering condition is, the check may be converted into a compile | |
3328 | -- time constraint check. | |
ee6ba406 | 3329 | |
3330 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
3331 | and then Present (Condition (R_Cno)) | |
3332 | then | |
3333 | Cond := Condition (R_Cno); | |
3334 | ||
f9bcba0d | 3335 | -- Insert the range check before the related context. Note that |
3336 | -- this action analyses the triggering condition. | |
ee6ba406 | 3337 | |
f9bcba0d | 3338 | Insert_Action (Ck_Node, R_Cno); |
3339 | ||
3340 | -- This old code doesn't make sense, why is the context flagged as | |
3341 | -- requiring dynamic range checks now in the middle of generating | |
3342 | -- them ??? | |
3343 | ||
3344 | if not Do_Static then | |
3345 | Set_Has_Dynamic_Range_Check (Ck_Node); | |
ee6ba406 | 3346 | end if; |
3347 | ||
f9bcba0d | 3348 | -- The triggering condition evaluates to True, the range check |
3349 | -- can be converted into a compile time constraint check. | |
ee6ba406 | 3350 | |
3351 | if Is_Entity_Name (Cond) | |
3352 | and then Entity (Cond) = Standard_True | |
3353 | then | |
feff2f05 | 3354 | -- Since an N_Range is technically not an expression, we have |
3355 | -- to set one of the bounds to C_E and then just flag the | |
3356 | -- N_Range. The warning message will point to the lower bound | |
3357 | -- and complain about a range, which seems OK. | |
ee6ba406 | 3358 | |
3359 | if Nkind (Ck_Node) = N_Range then | |
3360 | Apply_Compile_Time_Constraint_Error | |
5372d110 | 3361 | (Low_Bound (Ck_Node), |
3362 | "static range out of bounds of}??", | |
f15731c4 | 3363 | CE_Range_Check_Failed, |
ee6ba406 | 3364 | Ent => Target_Typ, |
3365 | Typ => Target_Typ); | |
3366 | ||
3367 | Set_Raises_Constraint_Error (Ck_Node); | |
3368 | ||
3369 | else | |
3370 | Apply_Compile_Time_Constraint_Error | |
5372d110 | 3371 | (Ck_Node, |
1581f2d7 | 3372 | "static value out of range of}??", |
f15731c4 | 3373 | CE_Range_Check_Failed, |
ee6ba406 | 3374 | Ent => Target_Typ, |
3375 | Typ => Target_Typ); | |
3376 | end if; | |
3377 | ||
3378 | -- If we were only doing a static check, or if checks are not | |
3379 | -- on, then we want to delete the check, since it is not needed. | |
3380 | -- We do this by replacing the if statement by a null statement | |
3381 | ||
3fabf0ca | 3382 | elsif Do_Static then |
00c403ee | 3383 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 3384 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
3385 | end if; | |
3386 | ||
4ee78e36 | 3387 | -- The range check raises Constraint_Error explicitly |
f9bcba0d | 3388 | |
ee6ba406 | 3389 | else |
3390 | Install_Static_Check (R_Cno, Loc); | |
3391 | end if; | |
ee6ba406 | 3392 | end loop; |
ee6ba406 | 3393 | end Apply_Selected_Range_Checks; |
3394 | ||
3395 | ------------------------------- | |
3396 | -- Apply_Static_Length_Check -- | |
3397 | ------------------------------- | |
3398 | ||
3399 | procedure Apply_Static_Length_Check | |
3400 | (Expr : Node_Id; | |
3401 | Target_Typ : Entity_Id; | |
3402 | Source_Typ : Entity_Id := Empty) | |
3403 | is | |
3404 | begin | |
3405 | Apply_Selected_Length_Checks | |
3406 | (Expr, Target_Typ, Source_Typ, Do_Static => True); | |
3407 | end Apply_Static_Length_Check; | |
3408 | ||
3409 | ------------------------------------- | |
3410 | -- Apply_Subscript_Validity_Checks -- | |
3411 | ------------------------------------- | |
3412 | ||
3413 | procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is | |
3414 | Sub : Node_Id; | |
3415 | ||
3416 | begin | |
3417 | pragma Assert (Nkind (Expr) = N_Indexed_Component); | |
3418 | ||
3419 | -- Loop through subscripts | |
3420 | ||
3421 | Sub := First (Expressions (Expr)); | |
3422 | while Present (Sub) loop | |
3423 | ||
feff2f05 | 3424 | -- Check one subscript. Note that we do not worry about enumeration |
3425 | -- type with holes, since we will convert the value to a Pos value | |
3426 | -- for the subscript, and that convert will do the necessary validity | |
3427 | -- check. | |
ee6ba406 | 3428 | |
3429 | Ensure_Valid (Sub, Holes_OK => True); | |
3430 | ||
3431 | -- Move to next subscript | |
3432 | ||
3433 | Sub := Next (Sub); | |
3434 | end loop; | |
3435 | end Apply_Subscript_Validity_Checks; | |
3436 | ||
3437 | ---------------------------------- | |
3438 | -- Apply_Type_Conversion_Checks -- | |
3439 | ---------------------------------- | |
3440 | ||
3441 | procedure Apply_Type_Conversion_Checks (N : Node_Id) is | |
3442 | Target_Type : constant Entity_Id := Etype (N); | |
3443 | Target_Base : constant Entity_Id := Base_Type (Target_Type); | |
9dfe12ae | 3444 | Expr : constant Node_Id := Expression (N); |
f4532fe1 | 3445 | |
3446 | Expr_Type : constant Entity_Id := Underlying_Type (Etype (Expr)); | |
141d591a | 3447 | -- Note: if Etype (Expr) is a private type without discriminants, its |
3448 | -- full view might have discriminants with defaults, so we need the | |
3449 | -- full view here to retrieve the constraints. | |
ee6ba406 | 3450 | |
3451 | begin | |
3452 | if Inside_A_Generic then | |
3453 | return; | |
3454 | ||
f15731c4 | 3455 | -- Skip these checks if serious errors detected, there are some nasty |
ee6ba406 | 3456 | -- situations of incomplete trees that blow things up. |
3457 | ||
f15731c4 | 3458 | elsif Serious_Errors_Detected > 0 then |
ee6ba406 | 3459 | return; |
3460 | ||
ea822fd4 | 3461 | -- Never generate discriminant checks for Unchecked_Union types |
3462 | ||
3463 | elsif Present (Expr_Type) | |
3464 | and then Is_Unchecked_Union (Expr_Type) | |
3465 | then | |
3466 | return; | |
3467 | ||
feff2f05 | 3468 | -- Scalar type conversions of the form Target_Type (Expr) require a |
3469 | -- range check if we cannot be sure that Expr is in the base type of | |
3470 | -- Target_Typ and also that Expr is in the range of Target_Typ. These | |
3471 | -- are not quite the same condition from an implementation point of | |
3472 | -- view, but clearly the second includes the first. | |
ee6ba406 | 3473 | |
3474 | elsif Is_Scalar_Type (Target_Type) then | |
3475 | declare | |
3476 | Conv_OK : constant Boolean := Conversion_OK (N); | |
feff2f05 | 3477 | -- If the Conversion_OK flag on the type conversion is set and no |
ea822fd4 | 3478 | -- floating-point type is involved in the type conversion then |
3479 | -- fixed-point values must be read as integral values. | |
ee6ba406 | 3480 | |
5329ca64 | 3481 | Float_To_Int : constant Boolean := |
b6341c67 | 3482 | Is_Floating_Point_Type (Expr_Type) |
3483 | and then Is_Integer_Type (Target_Type); | |
5329ca64 | 3484 | |
ee6ba406 | 3485 | begin |
ee6ba406 | 3486 | if not Overflow_Checks_Suppressed (Target_Base) |
0df9d43f | 3487 | and then not Overflow_Checks_Suppressed (Target_Type) |
e254d721 | 3488 | and then not |
7a1dabb3 | 3489 | In_Subrange_Of (Expr_Type, Target_Base, Fixed_Int => Conv_OK) |
5329ca64 | 3490 | and then not Float_To_Int |
ee6ba406 | 3491 | then |
4642b679 | 3492 | -- A small optimization: the attribute 'Pos applied to an |
c59f2b2d | 3493 | -- enumeration type has a known range, even though its type is |
3494 | -- Universal_Integer. So in numeric conversions it is usually | |
3495 | -- within range of the target integer type. Use the static | |
3496 | -- bounds of the base types to check. Disable this optimization | |
3497 | -- in case of a generic formal discrete type, because we don't | |
3498 | -- necessarily know the upper bound yet. | |
259716a0 | 3499 | |
3500 | if Nkind (Expr) = N_Attribute_Reference | |
3501 | and then Attribute_Name (Expr) = Name_Pos | |
3502 | and then Is_Enumeration_Type (Etype (Prefix (Expr))) | |
c59f2b2d | 3503 | and then not Is_Generic_Type (Etype (Prefix (Expr))) |
259716a0 | 3504 | and then Is_Integer_Type (Target_Type) |
3505 | then | |
3506 | declare | |
4642b679 | 3507 | Enum_T : constant Entity_Id := |
3508 | Root_Type (Etype (Prefix (Expr))); | |
3509 | Int_T : constant Entity_Id := Base_Type (Target_Type); | |
3510 | Last_I : constant Uint := | |
3511 | Intval (High_Bound (Scalar_Range (Int_T))); | |
3512 | Last_E : Uint; | |
259716a0 | 3513 | |
3514 | begin | |
4642b679 | 3515 | -- Character types have no explicit literals, so we use |
259716a0 | 3516 | -- the known number of characters in the type. |
3517 | ||
3518 | if Root_Type (Enum_T) = Standard_Character then | |
3519 | Last_E := UI_From_Int (255); | |
3520 | ||
3521 | elsif Enum_T = Standard_Wide_Character | |
3522 | or else Enum_T = Standard_Wide_Wide_Character | |
3523 | then | |
3524 | Last_E := UI_From_Int (65535); | |
3525 | ||
3526 | else | |
4642b679 | 3527 | Last_E := |
3528 | Enumeration_Pos | |
259716a0 | 3529 | (Entity (High_Bound (Scalar_Range (Enum_T)))); |
3530 | end if; | |
3531 | ||
3532 | if Last_E <= Last_I then | |
3533 | null; | |
3534 | ||
3535 | else | |
3536 | Activate_Overflow_Check (N); | |
3537 | end if; | |
3538 | end; | |
3539 | ||
3540 | else | |
3541 | Activate_Overflow_Check (N); | |
3542 | end if; | |
ee6ba406 | 3543 | end if; |
3544 | ||
3545 | if not Range_Checks_Suppressed (Target_Type) | |
3546 | and then not Range_Checks_Suppressed (Expr_Type) | |
3547 | then | |
54022749 | 3548 | if Float_To_Int |
3549 | and then not GNATprove_Mode | |
3550 | then | |
5329ca64 | 3551 | Apply_Float_Conversion_Check (Expr, Target_Type); |
f81a201b | 3552 | |
5329ca64 | 3553 | else |
7d97dbc9 | 3554 | -- Conversions involving fixed-point types are expanded |
3555 | -- separately, and do not need a Range_Check flag, except | |
c6056dd1 | 3556 | -- in GNATprove_Mode, where the explicit constraint check |
3557 | -- will not be generated. | |
7d97dbc9 | 3558 | |
95c16286 | 3559 | if GNATprove_Mode |
3560 | or else not Is_Fixed_Point_Type (Expr_Type) | |
7d97dbc9 | 3561 | then |
3562 | Apply_Scalar_Range_Check | |
3563 | (Expr, Target_Type, Fixed_Int => Conv_OK); | |
3564 | ||
3565 | else | |
3566 | Set_Do_Range_Check (Expression (N), False); | |
3567 | end if; | |
798afddc | 3568 | |
3569 | -- If the target type has predicates, we need to indicate | |
ea822fd4 | 3570 | -- the need for a check, even if Determine_Range finds that |
3571 | -- the value is within bounds. This may be the case e.g for | |
3572 | -- a division with a constant denominator. | |
798afddc | 3573 | |
3574 | if Has_Predicates (Target_Type) then | |
3575 | Enable_Range_Check (Expr); | |
3576 | end if; | |
5329ca64 | 3577 | end if; |
ee6ba406 | 3578 | end if; |
3579 | end; | |
3580 | ||
3581 | elsif Comes_From_Source (N) | |
f40f9731 | 3582 | and then not Discriminant_Checks_Suppressed (Target_Type) |
ee6ba406 | 3583 | and then Is_Record_Type (Target_Type) |
3584 | and then Is_Derived_Type (Target_Type) | |
3585 | and then not Is_Tagged_Type (Target_Type) | |
3586 | and then not Is_Constrained (Target_Type) | |
9dfe12ae | 3587 | and then Present (Stored_Constraint (Target_Type)) |
ee6ba406 | 3588 | then |
141d591a | 3589 | -- An unconstrained derived type may have inherited discriminant. |
9dfe12ae | 3590 | -- Build an actual discriminant constraint list using the stored |
ee6ba406 | 3591 | -- constraint, to verify that the expression of the parent type |
ea822fd4 | 3592 | -- satisfies the constraints imposed by the (unconstrained) derived |
3593 | -- type. This applies to value conversions, not to view conversions | |
3594 | -- of tagged types. | |
ee6ba406 | 3595 | |
3596 | declare | |
9dfe12ae | 3597 | Loc : constant Source_Ptr := Sloc (N); |
3598 | Cond : Node_Id; | |
3599 | Constraint : Elmt_Id; | |
3600 | Discr_Value : Node_Id; | |
3601 | Discr : Entity_Id; | |
3602 | ||
3603 | New_Constraints : constant Elist_Id := New_Elmt_List; | |
3604 | Old_Constraints : constant Elist_Id := | |
b6341c67 | 3605 | Discriminant_Constraint (Expr_Type); |
ee6ba406 | 3606 | |
3607 | begin | |
9dfe12ae | 3608 | Constraint := First_Elmt (Stored_Constraint (Target_Type)); |
ee6ba406 | 3609 | while Present (Constraint) loop |
3610 | Discr_Value := Node (Constraint); | |
3611 | ||
3612 | if Is_Entity_Name (Discr_Value) | |
3613 | and then Ekind (Entity (Discr_Value)) = E_Discriminant | |
3614 | then | |
3615 | Discr := Corresponding_Discriminant (Entity (Discr_Value)); | |
3616 | ||
3617 | if Present (Discr) | |
3618 | and then Scope (Discr) = Base_Type (Expr_Type) | |
3619 | then | |
3620 | -- Parent is constrained by new discriminant. Obtain | |
feff2f05 | 3621 | -- Value of original discriminant in expression. If the |
3622 | -- new discriminant has been used to constrain more than | |
3623 | -- one of the stored discriminants, this will provide the | |
3624 | -- required consistency check. | |
ee6ba406 | 3625 | |
55868293 | 3626 | Append_Elmt |
3627 | (Make_Selected_Component (Loc, | |
3628 | Prefix => | |
9dfe12ae | 3629 | Duplicate_Subexpr_No_Checks |
3630 | (Expr, Name_Req => True), | |
ee6ba406 | 3631 | Selector_Name => |
3632 | Make_Identifier (Loc, Chars (Discr))), | |
55868293 | 3633 | New_Constraints); |
ee6ba406 | 3634 | |
3635 | else | |
3636 | -- Discriminant of more remote ancestor ??? | |
3637 | ||
3638 | return; | |
3639 | end if; | |
3640 | ||
feff2f05 | 3641 | -- Derived type definition has an explicit value for this |
3642 | -- stored discriminant. | |
ee6ba406 | 3643 | |
3644 | else | |
3645 | Append_Elmt | |
9dfe12ae | 3646 | (Duplicate_Subexpr_No_Checks (Discr_Value), |
3647 | New_Constraints); | |
ee6ba406 | 3648 | end if; |
3649 | ||
3650 | Next_Elmt (Constraint); | |
3651 | end loop; | |
3652 | ||
3653 | -- Use the unconstrained expression type to retrieve the | |
3654 | -- discriminants of the parent, and apply momentarily the | |
3655 | -- discriminant constraint synthesized above. | |
3656 | ||
3657 | Set_Discriminant_Constraint (Expr_Type, New_Constraints); | |
3658 | Cond := Build_Discriminant_Checks (Expr, Expr_Type); | |
3659 | Set_Discriminant_Constraint (Expr_Type, Old_Constraints); | |
3660 | ||
3661 | Insert_Action (N, | |
f15731c4 | 3662 | Make_Raise_Constraint_Error (Loc, |
3663 | Condition => Cond, | |
3664 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 3665 | end; |
3666 | ||
175a6969 | 3667 | -- For arrays, checks are set now, but conversions are applied during |
3668 | -- expansion, to take into accounts changes of representation. The | |
3669 | -- checks become range checks on the base type or length checks on the | |
3670 | -- subtype, depending on whether the target type is unconstrained or | |
8e802312 | 3671 | -- constrained. Note that the range check is put on the expression of a |
3672 | -- type conversion, while the length check is put on the type conversion | |
3673 | -- itself. | |
175a6969 | 3674 | |
3675 | elsif Is_Array_Type (Target_Type) then | |
3676 | if Is_Constrained (Target_Type) then | |
3677 | Set_Do_Length_Check (N); | |
3678 | else | |
3679 | Set_Do_Range_Check (Expr); | |
3680 | end if; | |
ee6ba406 | 3681 | end if; |
ee6ba406 | 3682 | end Apply_Type_Conversion_Checks; |
3683 | ||
3684 | ---------------------------------------------- | |
3685 | -- Apply_Universal_Integer_Attribute_Checks -- | |
3686 | ---------------------------------------------- | |
3687 | ||
3688 | procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is | |
3689 | Loc : constant Source_Ptr := Sloc (N); | |
3690 | Typ : constant Entity_Id := Etype (N); | |
3691 | ||
3692 | begin | |
3693 | if Inside_A_Generic then | |
3694 | return; | |
3695 | ||
3696 | -- Nothing to do if checks are suppressed | |
3697 | ||
3698 | elsif Range_Checks_Suppressed (Typ) | |
3699 | and then Overflow_Checks_Suppressed (Typ) | |
3700 | then | |
3701 | return; | |
3702 | ||
3703 | -- Nothing to do if the attribute does not come from source. The | |
3704 | -- internal attributes we generate of this type do not need checks, | |
3705 | -- and furthermore the attempt to check them causes some circular | |
3706 | -- elaboration orders when dealing with packed types. | |
3707 | ||
3708 | elsif not Comes_From_Source (N) then | |
3709 | return; | |
3710 | ||
9dfe12ae | 3711 | -- If the prefix is a selected component that depends on a discriminant |
3712 | -- the check may improperly expose a discriminant instead of using | |
3713 | -- the bounds of the object itself. Set the type of the attribute to | |
3714 | -- the base type of the context, so that a check will be imposed when | |
3715 | -- needed (e.g. if the node appears as an index). | |
3716 | ||
3717 | elsif Nkind (Prefix (N)) = N_Selected_Component | |
3718 | and then Ekind (Typ) = E_Signed_Integer_Subtype | |
3719 | and then Depends_On_Discriminant (Scalar_Range (Typ)) | |
3720 | then | |
3721 | Set_Etype (N, Base_Type (Typ)); | |
3722 | ||
feff2f05 | 3723 | -- Otherwise, replace the attribute node with a type conversion node |
3724 | -- whose expression is the attribute, retyped to universal integer, and | |
3725 | -- whose subtype mark is the target type. The call to analyze this | |
3726 | -- conversion will set range and overflow checks as required for proper | |
3727 | -- detection of an out of range value. | |
ee6ba406 | 3728 | |
3729 | else | |
3730 | Set_Etype (N, Universal_Integer); | |
3731 | Set_Analyzed (N, True); | |
3732 | ||
3733 | Rewrite (N, | |
3734 | Make_Type_Conversion (Loc, | |
3735 | Subtype_Mark => New_Occurrence_Of (Typ, Loc), | |
3736 | Expression => Relocate_Node (N))); | |
3737 | ||
3738 | Analyze_And_Resolve (N, Typ); | |
3739 | return; | |
3740 | end if; | |
ee6ba406 | 3741 | end Apply_Universal_Integer_Attribute_Checks; |
3742 | ||
07c191b0 | 3743 | ------------------------------------- |
3744 | -- Atomic_Synchronization_Disabled -- | |
3745 | ------------------------------------- | |
3746 | ||
3747 | -- Note: internally Disable/Enable_Atomic_Synchronization is implemented | |
3748 | -- using a bogus check called Atomic_Synchronization. This is to make it | |
3749 | -- more convenient to get exactly the same semantics as [Un]Suppress. | |
3750 | ||
3751 | function Atomic_Synchronization_Disabled (E : Entity_Id) return Boolean is | |
3752 | begin | |
b444f81d | 3753 | -- If debug flag d.e is set, always return False, i.e. all atomic sync |
3754 | -- looks enabled, since it is never disabled. | |
3755 | ||
3756 | if Debug_Flag_Dot_E then | |
3757 | return False; | |
3758 | ||
3759 | -- If debug flag d.d is set then always return True, i.e. all atomic | |
3760 | -- sync looks disabled, since it always tests True. | |
3761 | ||
3762 | elsif Debug_Flag_Dot_D then | |
3763 | return True; | |
3764 | ||
3765 | -- If entity present, then check result for that entity | |
3766 | ||
3767 | elsif Present (E) and then Checks_May_Be_Suppressed (E) then | |
07c191b0 | 3768 | return Is_Check_Suppressed (E, Atomic_Synchronization); |
b444f81d | 3769 | |
3770 | -- Otherwise result depends on current scope setting | |
3771 | ||
07c191b0 | 3772 | else |
fafc6b97 | 3773 | return Scope_Suppress.Suppress (Atomic_Synchronization); |
07c191b0 | 3774 | end if; |
3775 | end Atomic_Synchronization_Disabled; | |
3776 | ||
ee6ba406 | 3777 | ------------------------------- |
3778 | -- Build_Discriminant_Checks -- | |
3779 | ------------------------------- | |
3780 | ||
3781 | function Build_Discriminant_Checks | |
3782 | (N : Node_Id; | |
314a23b6 | 3783 | T_Typ : Entity_Id) return Node_Id |
ee6ba406 | 3784 | is |
3785 | Loc : constant Source_Ptr := Sloc (N); | |
3786 | Cond : Node_Id; | |
3787 | Disc : Elmt_Id; | |
3788 | Disc_Ent : Entity_Id; | |
9dfe12ae | 3789 | Dref : Node_Id; |
ee6ba406 | 3790 | Dval : Node_Id; |
3791 | ||
84d0d4a5 | 3792 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id; |
3793 | ||
bacd5059 | 3794 | -------------------------------- |
3795 | -- Aggregate_Discriminant_Val -- | |
3796 | -------------------------------- | |
84d0d4a5 | 3797 | |
3798 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id is | |
3799 | Assoc : Node_Id; | |
3800 | ||
3801 | begin | |
feff2f05 | 3802 | -- The aggregate has been normalized with named associations. We use |
3803 | -- the Chars field to locate the discriminant to take into account | |
3804 | -- discriminants in derived types, which carry the same name as those | |
3805 | -- in the parent. | |
84d0d4a5 | 3806 | |
3807 | Assoc := First (Component_Associations (N)); | |
3808 | while Present (Assoc) loop | |
3809 | if Chars (First (Choices (Assoc))) = Chars (Disc) then | |
3810 | return Expression (Assoc); | |
3811 | else | |
3812 | Next (Assoc); | |
3813 | end if; | |
3814 | end loop; | |
3815 | ||
3816 | -- Discriminant must have been found in the loop above | |
3817 | ||
3818 | raise Program_Error; | |
3819 | end Aggregate_Discriminant_Val; | |
3820 | ||
3821 | -- Start of processing for Build_Discriminant_Checks | |
3822 | ||
ee6ba406 | 3823 | begin |
84d0d4a5 | 3824 | -- Loop through discriminants evolving the condition |
3825 | ||
ee6ba406 | 3826 | Cond := Empty; |
3827 | Disc := First_Elmt (Discriminant_Constraint (T_Typ)); | |
3828 | ||
9dfe12ae | 3829 | -- For a fully private type, use the discriminants of the parent type |
ee6ba406 | 3830 | |
3831 | if Is_Private_Type (T_Typ) | |
3832 | and then No (Full_View (T_Typ)) | |
3833 | then | |
3834 | Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ))); | |
3835 | else | |
3836 | Disc_Ent := First_Discriminant (T_Typ); | |
3837 | end if; | |
3838 | ||
3839 | while Present (Disc) loop | |
ee6ba406 | 3840 | Dval := Node (Disc); |
3841 | ||
3842 | if Nkind (Dval) = N_Identifier | |
3843 | and then Ekind (Entity (Dval)) = E_Discriminant | |
3844 | then | |
3845 | Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc); | |
3846 | else | |
9dfe12ae | 3847 | Dval := Duplicate_Subexpr_No_Checks (Dval); |
ee6ba406 | 3848 | end if; |
3849 | ||
00f91aef | 3850 | -- If we have an Unchecked_Union node, we can infer the discriminants |
3851 | -- of the node. | |
9dfe12ae | 3852 | |
00f91aef | 3853 | if Is_Unchecked_Union (Base_Type (T_Typ)) then |
3854 | Dref := New_Copy ( | |
3855 | Get_Discriminant_Value ( | |
3856 | First_Discriminant (T_Typ), | |
3857 | T_Typ, | |
3858 | Stored_Constraint (T_Typ))); | |
3859 | ||
84d0d4a5 | 3860 | elsif Nkind (N) = N_Aggregate then |
3861 | Dref := | |
3862 | Duplicate_Subexpr_No_Checks | |
3863 | (Aggregate_Discriminant_Val (Disc_Ent)); | |
3864 | ||
00f91aef | 3865 | else |
3866 | Dref := | |
3867 | Make_Selected_Component (Loc, | |
20cf157b | 3868 | Prefix => |
00f91aef | 3869 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
20cf157b | 3870 | Selector_Name => Make_Identifier (Loc, Chars (Disc_Ent))); |
00f91aef | 3871 | |
3872 | Set_Is_In_Discriminant_Check (Dref); | |
3873 | end if; | |
9dfe12ae | 3874 | |
ee6ba406 | 3875 | Evolve_Or_Else (Cond, |
3876 | Make_Op_Ne (Loc, | |
20cf157b | 3877 | Left_Opnd => Dref, |
ee6ba406 | 3878 | Right_Opnd => Dval)); |
3879 | ||
3880 | Next_Elmt (Disc); | |
3881 | Next_Discriminant (Disc_Ent); | |
3882 | end loop; | |
3883 | ||
3884 | return Cond; | |
3885 | end Build_Discriminant_Checks; | |
3886 | ||
13dbf220 | 3887 | ------------------ |
3888 | -- Check_Needed -- | |
3889 | ------------------ | |
3890 | ||
3891 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean is | |
3892 | N : Node_Id; | |
3893 | P : Node_Id; | |
3894 | K : Node_Kind; | |
3895 | L : Node_Id; | |
3896 | R : Node_Id; | |
3897 | ||
9b2068d4 | 3898 | function Left_Expression (Op : Node_Id) return Node_Id; |
3899 | -- Return the relevant expression from the left operand of the given | |
3900 | -- short circuit form: this is LO itself, except if LO is a qualified | |
3901 | -- expression, a type conversion, or an expression with actions, in | |
3902 | -- which case this is Left_Expression (Expression (LO)). | |
3903 | ||
3904 | --------------------- | |
3905 | -- Left_Expression -- | |
3906 | --------------------- | |
3907 | ||
3908 | function Left_Expression (Op : Node_Id) return Node_Id is | |
3909 | LE : Node_Id := Left_Opnd (Op); | |
3910 | begin | |
20cf157b | 3911 | while Nkind_In (LE, N_Qualified_Expression, |
3912 | N_Type_Conversion, | |
3913 | N_Expression_With_Actions) | |
9b2068d4 | 3914 | loop |
3915 | LE := Expression (LE); | |
3916 | end loop; | |
3917 | ||
3918 | return LE; | |
3919 | end Left_Expression; | |
3920 | ||
3921 | -- Start of processing for Check_Needed | |
3922 | ||
13dbf220 | 3923 | begin |
3924 | -- Always check if not simple entity | |
3925 | ||
3926 | if Nkind (Nod) not in N_Has_Entity | |
3927 | or else not Comes_From_Source (Nod) | |
3928 | then | |
3929 | return True; | |
3930 | end if; | |
3931 | ||
3932 | -- Look up tree for short circuit | |
3933 | ||
3934 | N := Nod; | |
3935 | loop | |
3936 | P := Parent (N); | |
3937 | K := Nkind (P); | |
3938 | ||
7b17e51b | 3939 | -- Done if out of subexpression (note that we allow generated stuff |
3940 | -- such as itype declarations in this context, to keep the loop going | |
3941 | -- since we may well have generated such stuff in complex situations. | |
3942 | -- Also done if no parent (probably an error condition, but no point | |
39a0c1d3 | 3943 | -- in behaving nasty if we find it). |
7b17e51b | 3944 | |
3945 | if No (P) | |
3946 | or else (K not in N_Subexpr and then Comes_From_Source (P)) | |
3947 | then | |
13dbf220 | 3948 | return True; |
3949 | ||
7b17e51b | 3950 | -- Or/Or Else case, where test is part of the right operand, or is |
3951 | -- part of one of the actions associated with the right operand, and | |
3952 | -- the left operand is an equality test. | |
13dbf220 | 3953 | |
7b17e51b | 3954 | elsif K = N_Op_Or then |
13dbf220 | 3955 | exit when N = Right_Opnd (P) |
9b2068d4 | 3956 | and then Nkind (Left_Expression (P)) = N_Op_Eq; |
13dbf220 | 3957 | |
7b17e51b | 3958 | elsif K = N_Or_Else then |
3959 | exit when (N = Right_Opnd (P) | |
3960 | or else | |
3961 | (Is_List_Member (N) | |
3962 | and then List_Containing (N) = Actions (P))) | |
9b2068d4 | 3963 | and then Nkind (Left_Expression (P)) = N_Op_Eq; |
13dbf220 | 3964 | |
7b17e51b | 3965 | -- Similar test for the And/And then case, where the left operand |
3966 | -- is an inequality test. | |
3967 | ||
3968 | elsif K = N_Op_And then | |
13dbf220 | 3969 | exit when N = Right_Opnd (P) |
9b2068d4 | 3970 | and then Nkind (Left_Expression (P)) = N_Op_Ne; |
7b17e51b | 3971 | |
3972 | elsif K = N_And_Then then | |
3973 | exit when (N = Right_Opnd (P) | |
3974 | or else | |
3975 | (Is_List_Member (N) | |
20cf157b | 3976 | and then List_Containing (N) = Actions (P))) |
9b2068d4 | 3977 | and then Nkind (Left_Expression (P)) = N_Op_Ne; |
13dbf220 | 3978 | end if; |
3979 | ||
3980 | N := P; | |
3981 | end loop; | |
3982 | ||
3983 | -- If we fall through the loop, then we have a conditional with an | |
9b2068d4 | 3984 | -- appropriate test as its left operand, so look further. |
3985 | ||
3986 | L := Left_Expression (P); | |
3987 | ||
3988 | -- L is an "=" or "/=" operator: extract its operands | |
13dbf220 | 3989 | |
13dbf220 | 3990 | R := Right_Opnd (L); |
3991 | L := Left_Opnd (L); | |
3992 | ||
3993 | -- Left operand of test must match original variable | |
3994 | ||
20cf157b | 3995 | if Nkind (L) not in N_Has_Entity or else Entity (L) /= Entity (Nod) then |
13dbf220 | 3996 | return True; |
3997 | end if; | |
3998 | ||
2af58f67 | 3999 | -- Right operand of test must be key value (zero or null) |
13dbf220 | 4000 | |
4001 | case Check is | |
4002 | when Access_Check => | |
2af58f67 | 4003 | if not Known_Null (R) then |
13dbf220 | 4004 | return True; |
4005 | end if; | |
4006 | ||
4007 | when Division_Check => | |
4008 | if not Compile_Time_Known_Value (R) | |
4009 | or else Expr_Value (R) /= Uint_0 | |
4010 | then | |
4011 | return True; | |
4012 | end if; | |
2af58f67 | 4013 | |
4014 | when others => | |
4015 | raise Program_Error; | |
13dbf220 | 4016 | end case; |
4017 | ||
4018 | -- Here we have the optimizable case, warn if not short-circuited | |
4019 | ||
4020 | if K = N_Op_And or else K = N_Op_Or then | |
c4968aa2 | 4021 | Error_Msg_Warn := SPARK_Mode /= On; |
4098232e | 4022 | |
13dbf220 | 4023 | case Check is |
4024 | when Access_Check => | |
4098232e | 4025 | if GNATprove_Mode then |
4026 | Error_Msg_N | |
4027 | ("Constraint_Error might have been raised (access check)", | |
4028 | Parent (Nod)); | |
4029 | else | |
4030 | Error_Msg_N | |
4031 | ("Constraint_Error may be raised (access check)??", | |
4032 | Parent (Nod)); | |
4033 | end if; | |
4034 | ||
13dbf220 | 4035 | when Division_Check => |
4098232e | 4036 | if GNATprove_Mode then |
4037 | Error_Msg_N | |
4038 | ("Constraint_Error might have been raised (zero divide)", | |
4039 | Parent (Nod)); | |
4040 | else | |
4041 | Error_Msg_N | |
4042 | ("Constraint_Error may be raised (zero divide)??", | |
4043 | Parent (Nod)); | |
4044 | end if; | |
2af58f67 | 4045 | |
4046 | when others => | |
4047 | raise Program_Error; | |
13dbf220 | 4048 | end case; |
4049 | ||
4050 | if K = N_Op_And then | |
e977c0cf | 4051 | Error_Msg_N -- CODEFIX |
cb97ae5c | 4052 | ("use `AND THEN` instead of AND??", P); |
13dbf220 | 4053 | else |
e977c0cf | 4054 | Error_Msg_N -- CODEFIX |
cb97ae5c | 4055 | ("use `OR ELSE` instead of OR??", P); |
13dbf220 | 4056 | end if; |
4057 | ||
6fb3c314 | 4058 | -- If not short-circuited, we need the check |
13dbf220 | 4059 | |
4060 | return True; | |
4061 | ||
4062 | -- If short-circuited, we can omit the check | |
4063 | ||
4064 | else | |
4065 | return False; | |
4066 | end if; | |
4067 | end Check_Needed; | |
4068 | ||
ee6ba406 | 4069 | ----------------------------------- |
4070 | -- Check_Valid_Lvalue_Subscripts -- | |
4071 | ----------------------------------- | |
4072 | ||
4073 | procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is | |
4074 | begin | |
4075 | -- Skip this if range checks are suppressed | |
4076 | ||
4077 | if Range_Checks_Suppressed (Etype (Expr)) then | |
4078 | return; | |
4079 | ||
feff2f05 | 4080 | -- Only do this check for expressions that come from source. We assume |
4081 | -- that expander generated assignments explicitly include any necessary | |
4082 | -- checks. Note that this is not just an optimization, it avoids | |
39a0c1d3 | 4083 | -- infinite recursions. |
ee6ba406 | 4084 | |
4085 | elsif not Comes_From_Source (Expr) then | |
4086 | return; | |
4087 | ||
4088 | -- For a selected component, check the prefix | |
4089 | ||
4090 | elsif Nkind (Expr) = N_Selected_Component then | |
4091 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
4092 | return; | |
4093 | ||
4094 | -- Case of indexed component | |
4095 | ||
4096 | elsif Nkind (Expr) = N_Indexed_Component then | |
4097 | Apply_Subscript_Validity_Checks (Expr); | |
4098 | ||
feff2f05 | 4099 | -- Prefix may itself be or contain an indexed component, and these |
4100 | -- subscripts need checking as well. | |
ee6ba406 | 4101 | |
4102 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
4103 | end if; | |
4104 | end Check_Valid_Lvalue_Subscripts; | |
4105 | ||
fa7497e8 | 4106 | ---------------------------------- |
4107 | -- Null_Exclusion_Static_Checks -- | |
4108 | ---------------------------------- | |
4109 | ||
e9998840 | 4110 | procedure Null_Exclusion_Static_Checks |
69733a9a | 4111 | (N : Node_Id; |
4112 | Comp : Node_Id := Empty; | |
4113 | Array_Comp : Boolean := False) | |
e9998840 | 4114 | is |
b1e656fb | 4115 | Has_Null : constant Boolean := Has_Null_Exclusion (N); |
4116 | Kind : constant Node_Kind := Nkind (N); | |
4117 | Error_Nod : Node_Id; | |
4118 | Expr : Node_Id; | |
4119 | Typ : Entity_Id; | |
fa7497e8 | 4120 | |
13dbf220 | 4121 | begin |
0577b0b1 | 4122 | pragma Assert |
b1e656fb | 4123 | (Nkind_In (Kind, N_Component_Declaration, |
4124 | N_Discriminant_Specification, | |
4125 | N_Function_Specification, | |
4126 | N_Object_Declaration, | |
4127 | N_Parameter_Specification)); | |
0577b0b1 | 4128 | |
b1e656fb | 4129 | if Kind = N_Function_Specification then |
0577b0b1 | 4130 | Typ := Etype (Defining_Entity (N)); |
4131 | else | |
4132 | Typ := Etype (Defining_Identifier (N)); | |
4133 | end if; | |
fa7497e8 | 4134 | |
b1e656fb | 4135 | case Kind is |
13dbf220 | 4136 | when N_Component_Declaration => |
4137 | if Present (Access_Definition (Component_Definition (N))) then | |
b1e656fb | 4138 | Error_Nod := Component_Definition (N); |
13dbf220 | 4139 | else |
b1e656fb | 4140 | Error_Nod := Subtype_Indication (Component_Definition (N)); |
13dbf220 | 4141 | end if; |
5329ca64 | 4142 | |
0577b0b1 | 4143 | when N_Discriminant_Specification => |
b1e656fb | 4144 | Error_Nod := Discriminant_Type (N); |
0577b0b1 | 4145 | |
4146 | when N_Function_Specification => | |
b1e656fb | 4147 | Error_Nod := Result_Definition (N); |
0577b0b1 | 4148 | |
4149 | when N_Object_Declaration => | |
b1e656fb | 4150 | Error_Nod := Object_Definition (N); |
0577b0b1 | 4151 | |
4152 | when N_Parameter_Specification => | |
b1e656fb | 4153 | Error_Nod := Parameter_Type (N); |
0577b0b1 | 4154 | |
13dbf220 | 4155 | when others => |
4156 | raise Program_Error; | |
4157 | end case; | |
5329ca64 | 4158 | |
0577b0b1 | 4159 | if Has_Null then |
5329ca64 | 4160 | |
0577b0b1 | 4161 | -- Enforce legality rule 3.10 (13): A null exclusion can only be |
4162 | -- applied to an access [sub]type. | |
5329ca64 | 4163 | |
0577b0b1 | 4164 | if not Is_Access_Type (Typ) then |
503f7fd3 | 4165 | Error_Msg_N |
b1e656fb | 4166 | ("`NOT NULL` allowed only for an access type", Error_Nod); |
5329ca64 | 4167 | |
feff2f05 | 4168 | -- Enforce legality rule RM 3.10(14/1): A null exclusion can only |
0577b0b1 | 4169 | -- be applied to a [sub]type that does not exclude null already. |
4170 | ||
b1e656fb | 4171 | elsif Can_Never_Be_Null (Typ) and then Comes_From_Source (Typ) then |
503f7fd3 | 4172 | Error_Msg_NE |
00c403ee | 4173 | ("`NOT NULL` not allowed (& already excludes null)", |
b1e656fb | 4174 | Error_Nod, Typ); |
0577b0b1 | 4175 | end if; |
13dbf220 | 4176 | end if; |
5329ca64 | 4177 | |
cc60bd16 | 4178 | -- Check that null-excluding objects are always initialized, except for |
4179 | -- deferred constants, for which the expression will appear in the full | |
4180 | -- declaration. | |
13dbf220 | 4181 | |
b1e656fb | 4182 | if Kind = N_Object_Declaration |
84d0d4a5 | 4183 | and then No (Expression (N)) |
cc60bd16 | 4184 | and then not Constant_Present (N) |
feff2f05 | 4185 | and then not No_Initialization (N) |
13dbf220 | 4186 | then |
e9998840 | 4187 | if Present (Comp) then |
4188 | ||
b1ff36e7 | 4189 | -- Specialize the warning message to indicate that we are dealing |
e9998840 | 4190 | -- with an uninitialized composite object that has a defaulted |
4191 | -- null-excluding component. | |
4192 | ||
4193 | Error_Msg_Name_1 := Chars (Defining_Identifier (Comp)); | |
4194 | Error_Msg_Name_2 := Chars (Defining_Identifier (N)); | |
4195 | ||
69733a9a | 4196 | Discard_Node |
4197 | (Compile_Time_Constraint_Error | |
4198 | (N => N, | |
4199 | Msg => | |
4200 | "(Ada 2005) null-excluding component % of object % must " | |
4201 | & "be initialized??", | |
4202 | Ent => Defining_Identifier (Comp))); | |
4203 | ||
4204 | -- This is a case of an array with null-excluding components, so | |
4205 | -- indicate that in the warning. | |
4206 | ||
4207 | elsif Array_Comp then | |
4208 | Discard_Node | |
4209 | (Compile_Time_Constraint_Error | |
4210 | (N => N, | |
4211 | Msg => | |
4212 | "(Ada 2005) null-excluding array components must " | |
4213 | & "be initialized??", | |
4214 | Ent => Defining_Identifier (N))); | |
4215 | ||
4216 | -- Normal case of object of a null-excluding access type | |
b1ff36e7 | 4217 | |
e9998840 | 4218 | else |
69733a9a | 4219 | -- Add an expression that assigns null. This node is needed by |
4220 | -- Apply_Compile_Time_Constraint_Error, which will replace this | |
4221 | -- with a Constraint_Error node. | |
4222 | ||
4223 | Set_Expression (N, Make_Null (Sloc (N))); | |
4224 | Set_Etype (Expression (N), Etype (Defining_Identifier (N))); | |
4225 | ||
e9998840 | 4226 | Apply_Compile_Time_Constraint_Error |
4227 | (N => Expression (N), | |
4228 | Msg => | |
4229 | "(Ada 2005) null-excluding objects must be initialized??", | |
4230 | Reason => CE_Null_Not_Allowed); | |
4231 | end if; | |
13dbf220 | 4232 | end if; |
5329ca64 | 4233 | |
cc60bd16 | 4234 | -- Check that a null-excluding component, formal or object is not being |
4235 | -- assigned a null value. Otherwise generate a warning message and | |
2c145f84 | 4236 | -- replace Expression (N) by an N_Constraint_Error node. |
13dbf220 | 4237 | |
b1e656fb | 4238 | if Kind /= N_Function_Specification then |
0577b0b1 | 4239 | Expr := Expression (N); |
5329ca64 | 4240 | |
2af58f67 | 4241 | if Present (Expr) and then Known_Null (Expr) then |
b1e656fb | 4242 | case Kind is |
99378362 | 4243 | when N_Component_Declaration |
4244 | | N_Discriminant_Specification | |
4245 | => | |
7189d17f | 4246 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 4247 | (N => Expr, |
99378362 | 4248 | Msg => |
4249 | "(Ada 2005) null not allowed in null-excluding " | |
4250 | & "components??", | |
0577b0b1 | 4251 | Reason => CE_Null_Not_Allowed); |
5329ca64 | 4252 | |
0577b0b1 | 4253 | when N_Object_Declaration => |
7189d17f | 4254 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 4255 | (N => Expr, |
99378362 | 4256 | Msg => |
4257 | "(Ada 2005) null not allowed in null-excluding " | |
4258 | & "objects??", | |
0577b0b1 | 4259 | Reason => CE_Null_Not_Allowed); |
5329ca64 | 4260 | |
0577b0b1 | 4261 | when N_Parameter_Specification => |
7189d17f | 4262 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 4263 | (N => Expr, |
99378362 | 4264 | Msg => |
4265 | "(Ada 2005) null not allowed in null-excluding " | |
4266 | & "formals??", | |
0577b0b1 | 4267 | Reason => CE_Null_Not_Allowed); |
13dbf220 | 4268 | |
4269 | when others => | |
4270 | null; | |
5329ca64 | 4271 | end case; |
4272 | end if; | |
0577b0b1 | 4273 | end if; |
fa7497e8 | 4274 | end Null_Exclusion_Static_Checks; |
4275 | ||
9dfe12ae | 4276 | ---------------------------------- |
4277 | -- Conditional_Statements_Begin -- | |
4278 | ---------------------------------- | |
4279 | ||
4280 | procedure Conditional_Statements_Begin is | |
4281 | begin | |
4282 | Saved_Checks_TOS := Saved_Checks_TOS + 1; | |
4283 | ||
feff2f05 | 4284 | -- If stack overflows, kill all checks, that way we know to simply reset |
4285 | -- the number of saved checks to zero on return. This should never occur | |
4286 | -- in practice. | |
9dfe12ae | 4287 | |
4288 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
4289 | Kill_All_Checks; | |
4290 | ||
feff2f05 | 4291 | -- In the normal case, we just make a new stack entry saving the current |
4292 | -- number of saved checks for a later restore. | |
9dfe12ae | 4293 | |
4294 | else | |
4295 | Saved_Checks_Stack (Saved_Checks_TOS) := Num_Saved_Checks; | |
4296 | ||
4297 | if Debug_Flag_CC then | |
4298 | w ("Conditional_Statements_Begin: Num_Saved_Checks = ", | |
4299 | Num_Saved_Checks); | |
4300 | end if; | |
4301 | end if; | |
4302 | end Conditional_Statements_Begin; | |
4303 | ||
4304 | -------------------------------- | |
4305 | -- Conditional_Statements_End -- | |
4306 | -------------------------------- | |
4307 | ||
4308 | procedure Conditional_Statements_End is | |
4309 | begin | |
4310 | pragma Assert (Saved_Checks_TOS > 0); | |
4311 | ||
feff2f05 | 4312 | -- If the saved checks stack overflowed, then we killed all checks, so |
4313 | -- setting the number of saved checks back to zero is correct. This | |
4314 | -- should never occur in practice. | |
9dfe12ae | 4315 | |
4316 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
4317 | Num_Saved_Checks := 0; | |
4318 | ||
feff2f05 | 4319 | -- In the normal case, restore the number of saved checks from the top |
4320 | -- stack entry. | |
9dfe12ae | 4321 | |
4322 | else | |
4323 | Num_Saved_Checks := Saved_Checks_Stack (Saved_Checks_TOS); | |
20cf157b | 4324 | |
9dfe12ae | 4325 | if Debug_Flag_CC then |
4326 | w ("Conditional_Statements_End: Num_Saved_Checks = ", | |
4327 | Num_Saved_Checks); | |
4328 | end if; | |
4329 | end if; | |
4330 | ||
4331 | Saved_Checks_TOS := Saved_Checks_TOS - 1; | |
4332 | end Conditional_Statements_End; | |
4333 | ||
3cce7f32 | 4334 | ------------------------- |
4335 | -- Convert_From_Bignum -- | |
4336 | ------------------------- | |
4337 | ||
4338 | function Convert_From_Bignum (N : Node_Id) return Node_Id is | |
4339 | Loc : constant Source_Ptr := Sloc (N); | |
4340 | ||
4341 | begin | |
4342 | pragma Assert (Is_RTE (Etype (N), RE_Bignum)); | |
4343 | ||
4344 | -- Construct call From Bignum | |
4345 | ||
4346 | return | |
4347 | Make_Function_Call (Loc, | |
4348 | Name => | |
4349 | New_Occurrence_Of (RTE (RE_From_Bignum), Loc), | |
4350 | Parameter_Associations => New_List (Relocate_Node (N))); | |
4351 | end Convert_From_Bignum; | |
4352 | ||
4353 | ----------------------- | |
4354 | -- Convert_To_Bignum -- | |
4355 | ----------------------- | |
4356 | ||
4357 | function Convert_To_Bignum (N : Node_Id) return Node_Id is | |
4358 | Loc : constant Source_Ptr := Sloc (N); | |
4359 | ||
4360 | begin | |
0326b4d4 | 4361 | -- Nothing to do if Bignum already except call Relocate_Node |
3cce7f32 | 4362 | |
4363 | if Is_RTE (Etype (N), RE_Bignum) then | |
4364 | return Relocate_Node (N); | |
4365 | ||
21a55437 | 4366 | -- Otherwise construct call to To_Bignum, converting the operand to the |
4367 | -- required Long_Long_Integer form. | |
3cce7f32 | 4368 | |
4369 | else | |
4370 | pragma Assert (Is_Signed_Integer_Type (Etype (N))); | |
4371 | return | |
4372 | Make_Function_Call (Loc, | |
4373 | Name => | |
4374 | New_Occurrence_Of (RTE (RE_To_Bignum), Loc), | |
4375 | Parameter_Associations => New_List ( | |
4376 | Convert_To (Standard_Long_Long_Integer, Relocate_Node (N)))); | |
4377 | end if; | |
4378 | end Convert_To_Bignum; | |
4379 | ||
ee6ba406 | 4380 | --------------------- |
4381 | -- Determine_Range -- | |
4382 | --------------------- | |
4383 | ||
6af1bdbc | 4384 | Cache_Size : constant := 2 ** 10; |
ee6ba406 | 4385 | type Cache_Index is range 0 .. Cache_Size - 1; |
39a0c1d3 | 4386 | -- Determine size of below cache (power of 2 is more efficient) |
ee6ba406 | 4387 | |
7ac8c2b1 | 4388 | Determine_Range_Cache_N : array (Cache_Index) of Node_Id; |
4389 | Determine_Range_Cache_V : array (Cache_Index) of Boolean; | |
4390 | Determine_Range_Cache_Lo : array (Cache_Index) of Uint; | |
4391 | Determine_Range_Cache_Hi : array (Cache_Index) of Uint; | |
4392 | Determine_Range_Cache_Lo_R : array (Cache_Index) of Ureal; | |
4393 | Determine_Range_Cache_Hi_R : array (Cache_Index) of Ureal; | |
feff2f05 | 4394 | -- The above arrays are used to implement a small direct cache for |
7ac8c2b1 | 4395 | -- Determine_Range and Determine_Range_R calls. Because of the way these |
4396 | -- subprograms recursively traces subexpressions, and because overflow | |
4397 | -- checking calls the routine on the way up the tree, a quadratic behavior | |
4398 | -- can otherwise be encountered in large expressions. The cache entry for | |
4399 | -- node N is stored in the (N mod Cache_Size) entry, and can be validated | |
4400 | -- by checking the actual node value stored there. The Range_Cache_V array | |
4401 | -- records the setting of Assume_Valid for the cache entry. | |
ee6ba406 | 4402 | |
4403 | procedure Determine_Range | |
9c486805 | 4404 | (N : Node_Id; |
4405 | OK : out Boolean; | |
4406 | Lo : out Uint; | |
4407 | Hi : out Uint; | |
4408 | Assume_Valid : Boolean := False) | |
ee6ba406 | 4409 | is |
e254d721 | 4410 | Typ : Entity_Id := Etype (N); |
4411 | -- Type to use, may get reset to base type for possibly invalid entity | |
8880be85 | 4412 | |
4413 | Lo_Left : Uint; | |
4414 | Hi_Left : Uint; | |
4415 | -- Lo and Hi bounds of left operand | |
ee6ba406 | 4416 | |
5bb74b99 | 4417 | Lo_Right : Uint := No_Uint; |
4418 | Hi_Right : Uint := No_Uint; | |
8880be85 | 4419 | -- Lo and Hi bounds of right (or only) operand |
4420 | ||
4421 | Bound : Node_Id; | |
4422 | -- Temp variable used to hold a bound node | |
4423 | ||
4424 | Hbound : Uint; | |
4425 | -- High bound of base type of expression | |
4426 | ||
4427 | Lor : Uint; | |
4428 | Hir : Uint; | |
4429 | -- Refined values for low and high bounds, after tightening | |
4430 | ||
4431 | OK1 : Boolean; | |
4432 | -- Used in lower level calls to indicate if call succeeded | |
4433 | ||
4434 | Cindex : Cache_Index; | |
4435 | -- Used to search cache | |
ee6ba406 | 4436 | |
094ed68e | 4437 | Btyp : Entity_Id; |
4438 | -- Base type | |
4439 | ||
ee6ba406 | 4440 | function OK_Operands return Boolean; |
4441 | -- Used for binary operators. Determines the ranges of the left and | |
4442 | -- right operands, and if they are both OK, returns True, and puts | |
341bd953 | 4443 | -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left. |
ee6ba406 | 4444 | |
4445 | ----------------- | |
4446 | -- OK_Operands -- | |
4447 | ----------------- | |
4448 | ||
4449 | function OK_Operands return Boolean is | |
4450 | begin | |
9c486805 | 4451 | Determine_Range |
4452 | (Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid); | |
ee6ba406 | 4453 | |
4454 | if not OK1 then | |
4455 | return False; | |
4456 | end if; | |
4457 | ||
9c486805 | 4458 | Determine_Range |
4459 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
ee6ba406 | 4460 | return OK1; |
4461 | end OK_Operands; | |
4462 | ||
4463 | -- Start of processing for Determine_Range | |
4464 | ||
4465 | begin | |
e12b2502 | 4466 | -- Prevent junk warnings by initializing range variables |
4467 | ||
4468 | Lo := No_Uint; | |
4469 | Hi := No_Uint; | |
4470 | Lor := No_Uint; | |
4471 | Hir := No_Uint; | |
4472 | ||
87bdc21d | 4473 | -- For temporary constants internally generated to remove side effects |
4474 | -- we must use the corresponding expression to determine the range of | |
e12b2502 | 4475 | -- the expression. But note that the expander can also generate |
4476 | -- constants in other cases, including deferred constants. | |
87bdc21d | 4477 | |
4478 | if Is_Entity_Name (N) | |
4479 | and then Nkind (Parent (Entity (N))) = N_Object_Declaration | |
4480 | and then Ekind (Entity (N)) = E_Constant | |
4481 | and then Is_Internal_Name (Chars (Entity (N))) | |
4482 | then | |
e12b2502 | 4483 | if Present (Expression (Parent (Entity (N)))) then |
4484 | Determine_Range | |
4485 | (Expression (Parent (Entity (N))), OK, Lo, Hi, Assume_Valid); | |
87bdc21d | 4486 | |
e12b2502 | 4487 | elsif Present (Full_View (Entity (N))) then |
4488 | Determine_Range | |
4489 | (Expression (Parent (Full_View (Entity (N)))), | |
4490 | OK, Lo, Hi, Assume_Valid); | |
ee6ba406 | 4491 | |
e12b2502 | 4492 | else |
4493 | OK := False; | |
4494 | end if; | |
4495 | return; | |
4496 | end if; | |
ee6ba406 | 4497 | |
a781c0fc | 4498 | -- If type is not defined, we can't determine its range |
ee6ba406 | 4499 | |
a781c0fc | 4500 | if No (Typ) |
4501 | ||
4502 | -- We don't deal with anything except discrete types | |
4503 | ||
4504 | or else not Is_Discrete_Type (Typ) | |
4505 | ||
cdfda0e3 | 4506 | -- Don't deal with enumerated types with non-standard representation |
4507 | ||
4508 | or else (Is_Enumeration_Type (Typ) | |
4509 | and then Present (Enum_Pos_To_Rep (Base_Type (Typ)))) | |
4510 | ||
a781c0fc | 4511 | -- Ignore type for which an error has been posted, since range in |
4512 | -- this case may well be a bogosity deriving from the error. Also | |
4513 | -- ignore if error posted on the reference node. | |
4514 | ||
4515 | or else Error_Posted (N) or else Error_Posted (Typ) | |
ee6ba406 | 4516 | then |
4517 | OK := False; | |
4518 | return; | |
4519 | end if; | |
4520 | ||
4521 | -- For all other cases, we can determine the range | |
4522 | ||
4523 | OK := True; | |
4524 | ||
feff2f05 | 4525 | -- If value is compile time known, then the possible range is the one |
39a0c1d3 | 4526 | -- value that we know this expression definitely has. |
ee6ba406 | 4527 | |
4528 | if Compile_Time_Known_Value (N) then | |
4529 | Lo := Expr_Value (N); | |
4530 | Hi := Lo; | |
4531 | return; | |
4532 | end if; | |
4533 | ||
4534 | -- Return if already in the cache | |
4535 | ||
4536 | Cindex := Cache_Index (N mod Cache_Size); | |
4537 | ||
9c486805 | 4538 | if Determine_Range_Cache_N (Cindex) = N |
4539 | and then | |
4540 | Determine_Range_Cache_V (Cindex) = Assume_Valid | |
4541 | then | |
ee6ba406 | 4542 | Lo := Determine_Range_Cache_Lo (Cindex); |
4543 | Hi := Determine_Range_Cache_Hi (Cindex); | |
4544 | return; | |
4545 | end if; | |
4546 | ||
feff2f05 | 4547 | -- Otherwise, start by finding the bounds of the type of the expression, |
4548 | -- the value cannot be outside this range (if it is, then we have an | |
4549 | -- overflow situation, which is a separate check, we are talking here | |
4550 | -- only about the expression value). | |
ee6ba406 | 4551 | |
341bd953 | 4552 | -- First a check, never try to find the bounds of a generic type, since |
4553 | -- these bounds are always junk values, and it is only valid to look at | |
4554 | -- the bounds in an instance. | |
4555 | ||
4556 | if Is_Generic_Type (Typ) then | |
4557 | OK := False; | |
4558 | return; | |
4559 | end if; | |
4560 | ||
9c486805 | 4561 | -- First step, change to use base type unless we know the value is valid |
e254d721 | 4562 | |
9c486805 | 4563 | if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N))) |
4564 | or else Assume_No_Invalid_Values | |
4565 | or else Assume_Valid | |
e254d721 | 4566 | then |
1916d94e | 4567 | -- If this is a known valid constant with a nonstatic value, it may |
4568 | -- have inherited a narrower subtype from its initial value; use this | |
4569 | -- saved subtype (see sem_ch3.adb). | |
4570 | ||
4571 | if Is_Entity_Name (N) | |
4572 | and then Ekind (Entity (N)) = E_Constant | |
4573 | and then Present (Actual_Subtype (Entity (N))) | |
4574 | then | |
4575 | Typ := Actual_Subtype (Entity (N)); | |
4576 | end if; | |
4577 | ||
9c486805 | 4578 | else |
4579 | Typ := Underlying_Type (Base_Type (Typ)); | |
e254d721 | 4580 | end if; |
4581 | ||
094ed68e | 4582 | -- Retrieve the base type. Handle the case where the base type is a |
4583 | -- private enumeration type. | |
4584 | ||
4585 | Btyp := Base_Type (Typ); | |
4586 | ||
4587 | if Is_Private_Type (Btyp) and then Present (Full_View (Btyp)) then | |
4588 | Btyp := Full_View (Btyp); | |
4589 | end if; | |
4590 | ||
feff2f05 | 4591 | -- We use the actual bound unless it is dynamic, in which case use the |
4592 | -- corresponding base type bound if possible. If we can't get a bound | |
4593 | -- then we figure we can't determine the range (a peculiar case, that | |
4594 | -- perhaps cannot happen, but there is no point in bombing in this | |
4595 | -- optimization circuit. | |
8880be85 | 4596 | |
4597 | -- First the low bound | |
ee6ba406 | 4598 | |
4599 | Bound := Type_Low_Bound (Typ); | |
4600 | ||
4601 | if Compile_Time_Known_Value (Bound) then | |
4602 | Lo := Expr_Value (Bound); | |
4603 | ||
094ed68e | 4604 | elsif Compile_Time_Known_Value (Type_Low_Bound (Btyp)) then |
4605 | Lo := Expr_Value (Type_Low_Bound (Btyp)); | |
ee6ba406 | 4606 | |
4607 | else | |
4608 | OK := False; | |
4609 | return; | |
4610 | end if; | |
4611 | ||
8880be85 | 4612 | -- Now the high bound |
4613 | ||
ee6ba406 | 4614 | Bound := Type_High_Bound (Typ); |
4615 | ||
8880be85 | 4616 | -- We need the high bound of the base type later on, and this should |
4617 | -- always be compile time known. Again, it is not clear that this | |
4618 | -- can ever be false, but no point in bombing. | |
ee6ba406 | 4619 | |
094ed68e | 4620 | if Compile_Time_Known_Value (Type_High_Bound (Btyp)) then |
4621 | Hbound := Expr_Value (Type_High_Bound (Btyp)); | |
ee6ba406 | 4622 | Hi := Hbound; |
4623 | ||
4624 | else | |
4625 | OK := False; | |
4626 | return; | |
4627 | end if; | |
4628 | ||
feff2f05 | 4629 | -- If we have a static subtype, then that may have a tighter bound so |
4630 | -- use the upper bound of the subtype instead in this case. | |
8880be85 | 4631 | |
4632 | if Compile_Time_Known_Value (Bound) then | |
4633 | Hi := Expr_Value (Bound); | |
4634 | end if; | |
4635 | ||
feff2f05 | 4636 | -- We may be able to refine this value in certain situations. If any |
4637 | -- refinement is possible, then Lor and Hir are set to possibly tighter | |
4638 | -- bounds, and OK1 is set to True. | |
ee6ba406 | 4639 | |
4640 | case Nkind (N) is | |
4641 | ||
4642 | -- For unary plus, result is limited by range of operand | |
4643 | ||
4644 | when N_Op_Plus => | |
9c486805 | 4645 | Determine_Range |
4646 | (Right_Opnd (N), OK1, Lor, Hir, Assume_Valid); | |
ee6ba406 | 4647 | |
4648 | -- For unary minus, determine range of operand, and negate it | |
4649 | ||
4650 | when N_Op_Minus => | |
9c486805 | 4651 | Determine_Range |
4652 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
ee6ba406 | 4653 | |
4654 | if OK1 then | |
4655 | Lor := -Hi_Right; | |
4656 | Hir := -Lo_Right; | |
4657 | end if; | |
4658 | ||
4659 | -- For binary addition, get range of each operand and do the | |
4660 | -- addition to get the result range. | |
4661 | ||
4662 | when N_Op_Add => | |
4663 | if OK_Operands then | |
4664 | Lor := Lo_Left + Lo_Right; | |
4665 | Hir := Hi_Left + Hi_Right; | |
4666 | end if; | |
4667 | ||
feff2f05 | 4668 | -- Division is tricky. The only case we consider is where the right |
4669 | -- operand is a positive constant, and in this case we simply divide | |
4670 | -- the bounds of the left operand | |
ee6ba406 | 4671 | |
4672 | when N_Op_Divide => | |
4673 | if OK_Operands then | |
4674 | if Lo_Right = Hi_Right | |
4675 | and then Lo_Right > 0 | |
4676 | then | |
4677 | Lor := Lo_Left / Lo_Right; | |
4678 | Hir := Hi_Left / Lo_Right; | |
ee6ba406 | 4679 | else |
4680 | OK1 := False; | |
4681 | end if; | |
4682 | end if; | |
4683 | ||
feff2f05 | 4684 | -- For binary subtraction, get range of each operand and do the worst |
4685 | -- case subtraction to get the result range. | |
ee6ba406 | 4686 | |
4687 | when N_Op_Subtract => | |
4688 | if OK_Operands then | |
4689 | Lor := Lo_Left - Hi_Right; | |
4690 | Hir := Hi_Left - Lo_Right; | |
4691 | end if; | |
4692 | ||
feff2f05 | 4693 | -- For MOD, if right operand is a positive constant, then result must |
4694 | -- be in the allowable range of mod results. | |
ee6ba406 | 4695 | |
4696 | when N_Op_Mod => | |
4697 | if OK_Operands then | |
9dfe12ae | 4698 | if Lo_Right = Hi_Right |
4699 | and then Lo_Right /= 0 | |
4700 | then | |
ee6ba406 | 4701 | if Lo_Right > 0 then |
4702 | Lor := Uint_0; | |
4703 | Hir := Lo_Right - 1; | |
4704 | ||
9dfe12ae | 4705 | else -- Lo_Right < 0 |
ee6ba406 | 4706 | Lor := Lo_Right + 1; |
4707 | Hir := Uint_0; | |
4708 | end if; | |
4709 | ||
4710 | else | |
4711 | OK1 := False; | |
4712 | end if; | |
4713 | end if; | |
4714 | ||
feff2f05 | 4715 | -- For REM, if right operand is a positive constant, then result must |
4716 | -- be in the allowable range of mod results. | |
ee6ba406 | 4717 | |
4718 | when N_Op_Rem => | |
4719 | if OK_Operands then | |
99378362 | 4720 | if Lo_Right = Hi_Right and then Lo_Right /= 0 then |
ee6ba406 | 4721 | declare |
4722 | Dval : constant Uint := (abs Lo_Right) - 1; | |
4723 | ||
4724 | begin | |
4725 | -- The sign of the result depends on the sign of the | |
4726 | -- dividend (but not on the sign of the divisor, hence | |
4727 | -- the abs operation above). | |
4728 | ||
4729 | if Lo_Left < 0 then | |
4730 | Lor := -Dval; | |
4731 | else | |
4732 | Lor := Uint_0; | |
4733 | end if; | |
4734 | ||
4735 | if Hi_Left < 0 then | |
4736 | Hir := Uint_0; | |
4737 | else | |
4738 | Hir := Dval; | |
4739 | end if; | |
4740 | end; | |
4741 | ||
4742 | else | |
4743 | OK1 := False; | |
4744 | end if; | |
4745 | end if; | |
4746 | ||
4747 | -- Attribute reference cases | |
4748 | ||
4749 | when N_Attribute_Reference => | |
4750 | case Attribute_Name (N) is | |
4751 | ||
4752 | -- For Pos/Val attributes, we can refine the range using the | |
ddbf7f2e | 4753 | -- possible range of values of the attribute expression. |
ee6ba406 | 4754 | |
99378362 | 4755 | when Name_Pos |
4756 | | Name_Val | |
4757 | => | |
9c486805 | 4758 | Determine_Range |
4759 | (First (Expressions (N)), OK1, Lor, Hir, Assume_Valid); | |
ee6ba406 | 4760 | |
4761 | -- For Length attribute, use the bounds of the corresponding | |
4762 | -- index type to refine the range. | |
4763 | ||
4764 | when Name_Length => | |
4765 | declare | |
4766 | Atyp : Entity_Id := Etype (Prefix (N)); | |
4767 | Inum : Nat; | |
4768 | Indx : Node_Id; | |
4769 | ||
4770 | LL, LU : Uint; | |
4771 | UL, UU : Uint; | |
4772 | ||
4773 | begin | |
4774 | if Is_Access_Type (Atyp) then | |
4775 | Atyp := Designated_Type (Atyp); | |
4776 | end if; | |
4777 | ||
4778 | -- For string literal, we know exact value | |
4779 | ||
4780 | if Ekind (Atyp) = E_String_Literal_Subtype then | |
4781 | OK := True; | |
4782 | Lo := String_Literal_Length (Atyp); | |
4783 | Hi := String_Literal_Length (Atyp); | |
4784 | return; | |
4785 | end if; | |
4786 | ||
4787 | -- Otherwise check for expression given | |
4788 | ||
4789 | if No (Expressions (N)) then | |
4790 | Inum := 1; | |
4791 | else | |
4792 | Inum := | |
4793 | UI_To_Int (Expr_Value (First (Expressions (N)))); | |
4794 | end if; | |
4795 | ||
4796 | Indx := First_Index (Atyp); | |
4797 | for J in 2 .. Inum loop | |
4798 | Indx := Next_Index (Indx); | |
4799 | end loop; | |
4800 | ||
9116df93 | 4801 | -- If the index type is a formal type or derived from |
c8da6114 | 4802 | -- one, the bounds are not static. |
4803 | ||
4804 | if Is_Generic_Type (Root_Type (Etype (Indx))) then | |
4805 | OK := False; | |
4806 | return; | |
4807 | end if; | |
4808 | ||
ee6ba406 | 4809 | Determine_Range |
9c486805 | 4810 | (Type_Low_Bound (Etype (Indx)), OK1, LL, LU, |
4811 | Assume_Valid); | |
ee6ba406 | 4812 | |
4813 | if OK1 then | |
4814 | Determine_Range | |
9c486805 | 4815 | (Type_High_Bound (Etype (Indx)), OK1, UL, UU, |
4816 | Assume_Valid); | |
ee6ba406 | 4817 | |
4818 | if OK1 then | |
4819 | ||
4820 | -- The maximum value for Length is the biggest | |
4821 | -- possible gap between the values of the bounds. | |
4822 | -- But of course, this value cannot be negative. | |
4823 | ||
9c486805 | 4824 | Hir := UI_Max (Uint_0, UU - LL + 1); |
ee6ba406 | 4825 | |
4826 | -- For constrained arrays, the minimum value for | |
4827 | -- Length is taken from the actual value of the | |
9116df93 | 4828 | -- bounds, since the index will be exactly of this |
4829 | -- subtype. | |
ee6ba406 | 4830 | |
4831 | if Is_Constrained (Atyp) then | |
9c486805 | 4832 | Lor := UI_Max (Uint_0, UL - LU + 1); |
ee6ba406 | 4833 | |
4834 | -- For an unconstrained array, the minimum value | |
4835 | -- for length is always zero. | |
4836 | ||
4837 | else | |
4838 | Lor := Uint_0; | |
4839 | end if; | |
4840 | end if; | |
4841 | end if; | |
4842 | end; | |
4843 | ||
4844 | -- No special handling for other attributes | |
9116df93 | 4845 | -- Probably more opportunities exist here??? |
ee6ba406 | 4846 | |
4847 | when others => | |
4848 | OK1 := False; | |
4849 | ||
4850 | end case; | |
4851 | ||
ee6ba406 | 4852 | when N_Type_Conversion => |
54022749 | 4853 | |
4854 | -- For type conversion from one discrete type to another, we can | |
4855 | -- refine the range using the converted value. | |
4856 | ||
4857 | if Is_Discrete_Type (Etype (Expression (N))) then | |
4858 | Determine_Range (Expression (N), OK1, Lor, Hir, Assume_Valid); | |
4859 | ||
4860 | -- When converting a float to an integer type, determine the range | |
4861 | -- in real first, and then convert the bounds using UR_To_Uint | |
4862 | -- which correctly rounds away from zero when half way between two | |
4863 | -- integers, as required by normal Ada 95 rounding semantics. It | |
4864 | -- is only possible because analysis in GNATprove rules out the | |
4865 | -- possibility of a NaN or infinite value. | |
4866 | ||
4867 | elsif GNATprove_Mode | |
4868 | and then Is_Floating_Point_Type (Etype (Expression (N))) | |
4869 | then | |
4870 | declare | |
4871 | Lor_Real, Hir_Real : Ureal; | |
4872 | begin | |
4873 | Determine_Range_R (Expression (N), OK1, Lor_Real, Hir_Real, | |
4874 | Assume_Valid); | |
4875 | ||
4876 | if OK1 then | |
4877 | Lor := UR_To_Uint (Lor_Real); | |
4878 | Hir := UR_To_Uint (Hir_Real); | |
4879 | end if; | |
4880 | end; | |
4881 | ||
4882 | else | |
4883 | OK1 := False; | |
4884 | end if; | |
ee6ba406 | 4885 | |
4886 | -- Nothing special to do for all other expression kinds | |
4887 | ||
4888 | when others => | |
4889 | OK1 := False; | |
4890 | Lor := No_Uint; | |
4891 | Hir := No_Uint; | |
4892 | end case; | |
4893 | ||
9116df93 | 4894 | -- At this stage, if OK1 is true, then we know that the actual result of |
4895 | -- the computed expression is in the range Lor .. Hir. We can use this | |
4896 | -- to restrict the possible range of results. | |
ee6ba406 | 4897 | |
4898 | if OK1 then | |
4899 | ||
9116df93 | 4900 | -- If the refined value of the low bound is greater than the type |
7ac8c2b1 | 4901 | -- low bound, then reset it to the more restrictive value. However, |
9116df93 | 4902 | -- we do NOT do this for the case of a modular type where the |
4903 | -- possible upper bound on the value is above the base type high | |
4904 | -- bound, because that means the result could wrap. | |
ee6ba406 | 4905 | |
4906 | if Lor > Lo | |
9116df93 | 4907 | and then not (Is_Modular_Integer_Type (Typ) and then Hir > Hbound) |
ee6ba406 | 4908 | then |
4909 | Lo := Lor; | |
4910 | end if; | |
4911 | ||
9116df93 | 4912 | -- Similarly, if the refined value of the high bound is less than the |
4913 | -- value so far, then reset it to the more restrictive value. Again, | |
4914 | -- we do not do this if the refined low bound is negative for a | |
4915 | -- modular type, since this would wrap. | |
ee6ba406 | 4916 | |
4917 | if Hir < Hi | |
9116df93 | 4918 | and then not (Is_Modular_Integer_Type (Typ) and then Lor < Uint_0) |
ee6ba406 | 4919 | then |
4920 | Hi := Hir; | |
4921 | end if; | |
4922 | end if; | |
4923 | ||
4924 | -- Set cache entry for future call and we are all done | |
4925 | ||
4926 | Determine_Range_Cache_N (Cindex) := N; | |
9c486805 | 4927 | Determine_Range_Cache_V (Cindex) := Assume_Valid; |
ee6ba406 | 4928 | Determine_Range_Cache_Lo (Cindex) := Lo; |
4929 | Determine_Range_Cache_Hi (Cindex) := Hi; | |
4930 | return; | |
4931 | ||
9116df93 | 4932 | -- If any exception occurs, it means that we have some bug in the compiler, |
4933 | -- possibly triggered by a previous error, or by some unforeseen peculiar | |
ee6ba406 | 4934 | -- occurrence. However, this is only an optimization attempt, so there is |
4935 | -- really no point in crashing the compiler. Instead we just decide, too | |
4936 | -- bad, we can't figure out a range in this case after all. | |
4937 | ||
4938 | exception | |
4939 | when others => | |
4940 | ||
4941 | -- Debug flag K disables this behavior (useful for debugging) | |
4942 | ||
4943 | if Debug_Flag_K then | |
4944 | raise; | |
4945 | else | |
4946 | OK := False; | |
4947 | Lo := No_Uint; | |
4948 | Hi := No_Uint; | |
4949 | return; | |
4950 | end if; | |
ee6ba406 | 4951 | end Determine_Range; |
4952 | ||
7ac8c2b1 | 4953 | ----------------------- |
4954 | -- Determine_Range_R -- | |
4955 | ----------------------- | |
4956 | ||
4957 | procedure Determine_Range_R | |
4958 | (N : Node_Id; | |
4959 | OK : out Boolean; | |
4960 | Lo : out Ureal; | |
4961 | Hi : out Ureal; | |
4962 | Assume_Valid : Boolean := False) | |
4963 | is | |
4964 | Typ : Entity_Id := Etype (N); | |
4965 | -- Type to use, may get reset to base type for possibly invalid entity | |
4966 | ||
4967 | Lo_Left : Ureal; | |
4968 | Hi_Left : Ureal; | |
4969 | -- Lo and Hi bounds of left operand | |
4970 | ||
5bb74b99 | 4971 | Lo_Right : Ureal := No_Ureal; |
4972 | Hi_Right : Ureal := No_Ureal; | |
7ac8c2b1 | 4973 | -- Lo and Hi bounds of right (or only) operand |
4974 | ||
4975 | Bound : Node_Id; | |
4976 | -- Temp variable used to hold a bound node | |
4977 | ||
4978 | Hbound : Ureal; | |
4979 | -- High bound of base type of expression | |
4980 | ||
4981 | Lor : Ureal; | |
4982 | Hir : Ureal; | |
4983 | -- Refined values for low and high bounds, after tightening | |
4984 | ||
4985 | OK1 : Boolean; | |
4986 | -- Used in lower level calls to indicate if call succeeded | |
4987 | ||
4988 | Cindex : Cache_Index; | |
4989 | -- Used to search cache | |
4990 | ||
4991 | Btyp : Entity_Id; | |
4992 | -- Base type | |
4993 | ||
4994 | function OK_Operands return Boolean; | |
4995 | -- Used for binary operators. Determines the ranges of the left and | |
4996 | -- right operands, and if they are both OK, returns True, and puts | |
4997 | -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left. | |
4998 | ||
4999 | function Round_Machine (B : Ureal) return Ureal; | |
5000 | -- B is a real bound. Round it using mode Round_Even. | |
5001 | ||
5002 | ----------------- | |
5003 | -- OK_Operands -- | |
5004 | ----------------- | |
5005 | ||
5006 | function OK_Operands return Boolean is | |
5007 | begin | |
5008 | Determine_Range_R | |
5009 | (Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid); | |
5010 | ||
5011 | if not OK1 then | |
5012 | return False; | |
5013 | end if; | |
5014 | ||
5015 | Determine_Range_R | |
5016 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
5017 | return OK1; | |
5018 | end OK_Operands; | |
5019 | ||
5020 | ------------------- | |
5021 | -- Round_Machine -- | |
5022 | ------------------- | |
5023 | ||
5024 | function Round_Machine (B : Ureal) return Ureal is | |
5025 | begin | |
5026 | return Machine (Typ, B, Round_Even, N); | |
5027 | end Round_Machine; | |
5028 | ||
5029 | -- Start of processing for Determine_Range_R | |
5030 | ||
5031 | begin | |
5032 | -- Prevent junk warnings by initializing range variables | |
5033 | ||
5034 | Lo := No_Ureal; | |
5035 | Hi := No_Ureal; | |
5036 | Lor := No_Ureal; | |
5037 | Hir := No_Ureal; | |
5038 | ||
5039 | -- For temporary constants internally generated to remove side effects | |
5040 | -- we must use the corresponding expression to determine the range of | |
5041 | -- the expression. But note that the expander can also generate | |
5042 | -- constants in other cases, including deferred constants. | |
5043 | ||
5044 | if Is_Entity_Name (N) | |
5045 | and then Nkind (Parent (Entity (N))) = N_Object_Declaration | |
5046 | and then Ekind (Entity (N)) = E_Constant | |
5047 | and then Is_Internal_Name (Chars (Entity (N))) | |
5048 | then | |
5049 | if Present (Expression (Parent (Entity (N)))) then | |
5050 | Determine_Range_R | |
5051 | (Expression (Parent (Entity (N))), OK, Lo, Hi, Assume_Valid); | |
5052 | ||
5053 | elsif Present (Full_View (Entity (N))) then | |
5054 | Determine_Range_R | |
5055 | (Expression (Parent (Full_View (Entity (N)))), | |
5056 | OK, Lo, Hi, Assume_Valid); | |
5057 | ||
5058 | else | |
5059 | OK := False; | |
5060 | end if; | |
4c1c7f3f | 5061 | |
7ac8c2b1 | 5062 | return; |
5063 | end if; | |
5064 | ||
5065 | -- If type is not defined, we can't determine its range | |
5066 | ||
5067 | if No (Typ) | |
5068 | ||
5069 | -- We don't deal with anything except IEEE floating-point types | |
5070 | ||
5071 | or else not Is_Floating_Point_Type (Typ) | |
5072 | or else Float_Rep (Typ) /= IEEE_Binary | |
5073 | ||
5074 | -- Ignore type for which an error has been posted, since range in | |
5075 | -- this case may well be a bogosity deriving from the error. Also | |
5076 | -- ignore if error posted on the reference node. | |
5077 | ||
5078 | or else Error_Posted (N) or else Error_Posted (Typ) | |
5079 | then | |
5080 | OK := False; | |
5081 | return; | |
5082 | end if; | |
5083 | ||
5084 | -- For all other cases, we can determine the range | |
5085 | ||
5086 | OK := True; | |
5087 | ||
5088 | -- If value is compile time known, then the possible range is the one | |
5089 | -- value that we know this expression definitely has. | |
5090 | ||
5091 | if Compile_Time_Known_Value (N) then | |
5092 | Lo := Expr_Value_R (N); | |
5093 | Hi := Lo; | |
5094 | return; | |
5095 | end if; | |
5096 | ||
5097 | -- Return if already in the cache | |
5098 | ||
5099 | Cindex := Cache_Index (N mod Cache_Size); | |
5100 | ||
5101 | if Determine_Range_Cache_N (Cindex) = N | |
5102 | and then | |
5103 | Determine_Range_Cache_V (Cindex) = Assume_Valid | |
5104 | then | |
5105 | Lo := Determine_Range_Cache_Lo_R (Cindex); | |
5106 | Hi := Determine_Range_Cache_Hi_R (Cindex); | |
5107 | return; | |
5108 | end if; | |
5109 | ||
5110 | -- Otherwise, start by finding the bounds of the type of the expression, | |
5111 | -- the value cannot be outside this range (if it is, then we have an | |
5112 | -- overflow situation, which is a separate check, we are talking here | |
5113 | -- only about the expression value). | |
5114 | ||
5115 | -- First a check, never try to find the bounds of a generic type, since | |
5116 | -- these bounds are always junk values, and it is only valid to look at | |
5117 | -- the bounds in an instance. | |
5118 | ||
5119 | if Is_Generic_Type (Typ) then | |
5120 | OK := False; | |
5121 | return; | |
5122 | end if; | |
5123 | ||
5124 | -- First step, change to use base type unless we know the value is valid | |
5125 | ||
5126 | if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N))) | |
5127 | or else Assume_No_Invalid_Values | |
5128 | or else Assume_Valid | |
5129 | then | |
5130 | null; | |
5131 | else | |
5132 | Typ := Underlying_Type (Base_Type (Typ)); | |
5133 | end if; | |
5134 | ||
5135 | -- Retrieve the base type. Handle the case where the base type is a | |
5136 | -- private type. | |
5137 | ||
5138 | Btyp := Base_Type (Typ); | |
5139 | ||
5140 | if Is_Private_Type (Btyp) and then Present (Full_View (Btyp)) then | |
5141 | Btyp := Full_View (Btyp); | |
5142 | end if; | |
5143 | ||
5144 | -- We use the actual bound unless it is dynamic, in which case use the | |
5145 | -- corresponding base type bound if possible. If we can't get a bound | |
5146 | -- then we figure we can't determine the range (a peculiar case, that | |
5147 | -- perhaps cannot happen, but there is no point in bombing in this | |
5148 | -- optimization circuit). | |
5149 | ||
5150 | -- First the low bound | |
5151 | ||
5152 | Bound := Type_Low_Bound (Typ); | |
5153 | ||
5154 | if Compile_Time_Known_Value (Bound) then | |
5155 | Lo := Expr_Value_R (Bound); | |
5156 | ||
5157 | elsif Compile_Time_Known_Value (Type_Low_Bound (Btyp)) then | |
5158 | Lo := Expr_Value_R (Type_Low_Bound (Btyp)); | |
5159 | ||
5160 | else | |
5161 | OK := False; | |
5162 | return; | |
5163 | end if; | |
5164 | ||
5165 | -- Now the high bound | |
5166 | ||
5167 | Bound := Type_High_Bound (Typ); | |
5168 | ||
5169 | -- We need the high bound of the base type later on, and this should | |
5170 | -- always be compile time known. Again, it is not clear that this | |
5171 | -- can ever be false, but no point in bombing. | |
5172 | ||
5173 | if Compile_Time_Known_Value (Type_High_Bound (Btyp)) then | |
5174 | Hbound := Expr_Value_R (Type_High_Bound (Btyp)); | |
5175 | Hi := Hbound; | |
5176 | ||
5177 | else | |
5178 | OK := False; | |
5179 | return; | |
5180 | end if; | |
5181 | ||
5182 | -- If we have a static subtype, then that may have a tighter bound so | |
5183 | -- use the upper bound of the subtype instead in this case. | |
5184 | ||
5185 | if Compile_Time_Known_Value (Bound) then | |
5186 | Hi := Expr_Value_R (Bound); | |
5187 | end if; | |
5188 | ||
5189 | -- We may be able to refine this value in certain situations. If any | |
5190 | -- refinement is possible, then Lor and Hir are set to possibly tighter | |
5191 | -- bounds, and OK1 is set to True. | |
5192 | ||
5193 | case Nkind (N) is | |
5194 | ||
5195 | -- For unary plus, result is limited by range of operand | |
5196 | ||
5197 | when N_Op_Plus => | |
5198 | Determine_Range_R | |
5199 | (Right_Opnd (N), OK1, Lor, Hir, Assume_Valid); | |
5200 | ||
5201 | -- For unary minus, determine range of operand, and negate it | |
5202 | ||
5203 | when N_Op_Minus => | |
5204 | Determine_Range_R | |
5205 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
5206 | ||
5207 | if OK1 then | |
5208 | Lor := -Hi_Right; | |
5209 | Hir := -Lo_Right; | |
5210 | end if; | |
5211 | ||
5212 | -- For binary addition, get range of each operand and do the | |
5213 | -- addition to get the result range. | |
5214 | ||
5215 | when N_Op_Add => | |
5216 | if OK_Operands then | |
5217 | Lor := Round_Machine (Lo_Left + Lo_Right); | |
5218 | Hir := Round_Machine (Hi_Left + Hi_Right); | |
5219 | end if; | |
5220 | ||
5221 | -- For binary subtraction, get range of each operand and do the worst | |
5222 | -- case subtraction to get the result range. | |
5223 | ||
5224 | when N_Op_Subtract => | |
5225 | if OK_Operands then | |
5226 | Lor := Round_Machine (Lo_Left - Hi_Right); | |
5227 | Hir := Round_Machine (Hi_Left - Lo_Right); | |
5228 | end if; | |
5229 | ||
5230 | -- For multiplication, get range of each operand and do the | |
5231 | -- four multiplications to get the result range. | |
5232 | ||
5233 | when N_Op_Multiply => | |
5234 | if OK_Operands then | |
5235 | declare | |
5236 | M1 : constant Ureal := Round_Machine (Lo_Left * Lo_Right); | |
5237 | M2 : constant Ureal := Round_Machine (Lo_Left * Hi_Right); | |
5238 | M3 : constant Ureal := Round_Machine (Hi_Left * Lo_Right); | |
5239 | M4 : constant Ureal := Round_Machine (Hi_Left * Hi_Right); | |
552d7cbc | 5240 | |
7ac8c2b1 | 5241 | begin |
5242 | Lor := UR_Min (UR_Min (M1, M2), UR_Min (M3, M4)); | |
5243 | Hir := UR_Max (UR_Max (M1, M2), UR_Max (M3, M4)); | |
5244 | end; | |
5245 | end if; | |
5246 | ||
5247 | -- For division, consider separately the cases where the right | |
5248 | -- operand is positive or negative. Otherwise, the right operand | |
5249 | -- can be arbitrarily close to zero, so the result is likely to | |
5250 | -- be unbounded in one direction, do not attempt to compute it. | |
5251 | ||
5252 | when N_Op_Divide => | |
5253 | if OK_Operands then | |
5254 | ||
5255 | -- Right operand is positive | |
5256 | ||
5257 | if Lo_Right > Ureal_0 then | |
5258 | ||
5259 | -- If the low bound of the left operand is negative, obtain | |
5260 | -- the overall low bound by dividing it by the smallest | |
5261 | -- value of the right operand, and otherwise by the largest | |
5262 | -- value of the right operand. | |
5263 | ||
5264 | if Lo_Left < Ureal_0 then | |
5265 | Lor := Round_Machine (Lo_Left / Lo_Right); | |
5266 | else | |
5267 | Lor := Round_Machine (Lo_Left / Hi_Right); | |
5268 | end if; | |
5269 | ||
5270 | -- If the high bound of the left operand is negative, obtain | |
5271 | -- the overall high bound by dividing it by the largest | |
5272 | -- value of the right operand, and otherwise by the | |
5273 | -- smallest value of the right operand. | |
5274 | ||
5275 | if Hi_Left < Ureal_0 then | |
5276 | Hir := Round_Machine (Hi_Left / Hi_Right); | |
5277 | else | |
5278 | Hir := Round_Machine (Hi_Left / Lo_Right); | |
5279 | end if; | |
5280 | ||
5281 | -- Right operand is negative | |
5282 | ||
5283 | elsif Hi_Right < Ureal_0 then | |
5284 | ||
5285 | -- If the low bound of the left operand is negative, obtain | |
5286 | -- the overall low bound by dividing it by the largest | |
5287 | -- value of the right operand, and otherwise by the smallest | |
5288 | -- value of the right operand. | |
5289 | ||
5290 | if Lo_Left < Ureal_0 then | |
5291 | Lor := Round_Machine (Lo_Left / Hi_Right); | |
5292 | else | |
5293 | Lor := Round_Machine (Lo_Left / Lo_Right); | |
5294 | end if; | |
5295 | ||
5296 | -- If the high bound of the left operand is negative, obtain | |
5297 | -- the overall high bound by dividing it by the smallest | |
5298 | -- value of the right operand, and otherwise by the | |
5299 | -- largest value of the right operand. | |
5300 | ||
5301 | if Hi_Left < Ureal_0 then | |
5302 | Hir := Round_Machine (Hi_Left / Lo_Right); | |
5303 | else | |
5304 | Hir := Round_Machine (Hi_Left / Hi_Right); | |
5305 | end if; | |
5306 | ||
5307 | else | |
5308 | OK1 := False; | |
5309 | end if; | |
5310 | end if; | |
5311 | ||
7ac8c2b1 | 5312 | when N_Type_Conversion => |
3c5c732f | 5313 | |
5314 | -- For type conversion from one floating-point type to another, we | |
5315 | -- can refine the range using the converted value. | |
5316 | ||
5317 | if Is_Floating_Point_Type (Etype (Expression (N))) then | |
5318 | Determine_Range_R (Expression (N), OK1, Lor, Hir, Assume_Valid); | |
5319 | ||
5320 | -- When converting an integer to a floating-point type, determine | |
5321 | -- the range in integer first, and then convert the bounds. | |
5322 | ||
5323 | elsif Is_Discrete_Type (Etype (Expression (N))) then | |
5324 | declare | |
552d7cbc | 5325 | Hir_Int : Uint; |
5326 | Lor_Int : Uint; | |
5327 | ||
3c5c732f | 5328 | begin |
552d7cbc | 5329 | Determine_Range |
5330 | (Expression (N), OK1, Lor_Int, Hir_Int, Assume_Valid); | |
3c5c732f | 5331 | |
5332 | if OK1 then | |
5333 | Lor := Round_Machine (UR_From_Uint (Lor_Int)); | |
5334 | Hir := Round_Machine (UR_From_Uint (Hir_Int)); | |
5335 | end if; | |
5336 | end; | |
5337 | ||
5338 | else | |
5339 | OK1 := False; | |
5340 | end if; | |
7ac8c2b1 | 5341 | |
5342 | -- Nothing special to do for all other expression kinds | |
5343 | ||
5344 | when others => | |
5345 | OK1 := False; | |
5346 | Lor := No_Ureal; | |
5347 | Hir := No_Ureal; | |
5348 | end case; | |
5349 | ||
5350 | -- At this stage, if OK1 is true, then we know that the actual result of | |
5351 | -- the computed expression is in the range Lor .. Hir. We can use this | |
5352 | -- to restrict the possible range of results. | |
5353 | ||
5354 | if OK1 then | |
5355 | ||
5356 | -- If the refined value of the low bound is greater than the type | |
5357 | -- low bound, then reset it to the more restrictive value. | |
5358 | ||
5359 | if Lor > Lo then | |
5360 | Lo := Lor; | |
5361 | end if; | |
5362 | ||
5363 | -- Similarly, if the refined value of the high bound is less than the | |
5364 | -- value so far, then reset it to the more restrictive value. | |
5365 | ||
5366 | if Hir < Hi then | |
5367 | Hi := Hir; | |
5368 | end if; | |
5369 | end if; | |
5370 | ||
5371 | -- Set cache entry for future call and we are all done | |
5372 | ||
5373 | Determine_Range_Cache_N (Cindex) := N; | |
5374 | Determine_Range_Cache_V (Cindex) := Assume_Valid; | |
5375 | Determine_Range_Cache_Lo_R (Cindex) := Lo; | |
5376 | Determine_Range_Cache_Hi_R (Cindex) := Hi; | |
5377 | return; | |
5378 | ||
5379 | -- If any exception occurs, it means that we have some bug in the compiler, | |
5380 | -- possibly triggered by a previous error, or by some unforeseen peculiar | |
5381 | -- occurrence. However, this is only an optimization attempt, so there is | |
5382 | -- really no point in crashing the compiler. Instead we just decide, too | |
5383 | -- bad, we can't figure out a range in this case after all. | |
5384 | ||
5385 | exception | |
5386 | when others => | |
5387 | ||
5388 | -- Debug flag K disables this behavior (useful for debugging) | |
5389 | ||
5390 | if Debug_Flag_K then | |
5391 | raise; | |
5392 | else | |
5393 | OK := False; | |
5394 | Lo := No_Ureal; | |
5395 | Hi := No_Ureal; | |
5396 | return; | |
5397 | end if; | |
5398 | end Determine_Range_R; | |
5399 | ||
ee6ba406 | 5400 | ------------------------------------ |
5401 | -- Discriminant_Checks_Suppressed -- | |
5402 | ------------------------------------ | |
5403 | ||
5404 | function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5405 | begin | |
9dfe12ae | 5406 | if Present (E) then |
5407 | if Is_Unchecked_Union (E) then | |
5408 | return True; | |
5409 | elsif Checks_May_Be_Suppressed (E) then | |
5410 | return Is_Check_Suppressed (E, Discriminant_Check); | |
5411 | end if; | |
5412 | end if; | |
5413 | ||
fafc6b97 | 5414 | return Scope_Suppress.Suppress (Discriminant_Check); |
ee6ba406 | 5415 | end Discriminant_Checks_Suppressed; |
5416 | ||
5417 | -------------------------------- | |
5418 | -- Division_Checks_Suppressed -- | |
5419 | -------------------------------- | |
5420 | ||
5421 | function Division_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5422 | begin | |
9dfe12ae | 5423 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
5424 | return Is_Check_Suppressed (E, Division_Check); | |
5425 | else | |
fafc6b97 | 5426 | return Scope_Suppress.Suppress (Division_Check); |
9dfe12ae | 5427 | end if; |
ee6ba406 | 5428 | end Division_Checks_Suppressed; |
5429 | ||
fa771c05 | 5430 | -------------------------------------- |
5431 | -- Duplicated_Tag_Checks_Suppressed -- | |
5432 | -------------------------------------- | |
5433 | ||
5434 | function Duplicated_Tag_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5435 | begin | |
5436 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
5437 | return Is_Check_Suppressed (E, Duplicated_Tag_Check); | |
5438 | else | |
5439 | return Scope_Suppress.Suppress (Duplicated_Tag_Check); | |
5440 | end if; | |
5441 | end Duplicated_Tag_Checks_Suppressed; | |
5442 | ||
ee6ba406 | 5443 | ----------------------------------- |
5444 | -- Elaboration_Checks_Suppressed -- | |
5445 | ----------------------------------- | |
5446 | ||
5447 | function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5448 | begin | |
38f5559f | 5449 | -- The complication in this routine is that if we are in the dynamic |
5450 | -- model of elaboration, we also check All_Checks, since All_Checks | |
5451 | -- does not set Elaboration_Check explicitly. | |
5452 | ||
9dfe12ae | 5453 | if Present (E) then |
5454 | if Kill_Elaboration_Checks (E) then | |
5455 | return True; | |
38f5559f | 5456 | |
9dfe12ae | 5457 | elsif Checks_May_Be_Suppressed (E) then |
38f5559f | 5458 | if Is_Check_Suppressed (E, Elaboration_Check) then |
5459 | return True; | |
fe48a434 | 5460 | |
38f5559f | 5461 | elsif Dynamic_Elaboration_Checks then |
5462 | return Is_Check_Suppressed (E, All_Checks); | |
fe48a434 | 5463 | |
38f5559f | 5464 | else |
5465 | return False; | |
5466 | end if; | |
9dfe12ae | 5467 | end if; |
5468 | end if; | |
5469 | ||
fafc6b97 | 5470 | if Scope_Suppress.Suppress (Elaboration_Check) then |
38f5559f | 5471 | return True; |
fe48a434 | 5472 | |
38f5559f | 5473 | elsif Dynamic_Elaboration_Checks then |
fafc6b97 | 5474 | return Scope_Suppress.Suppress (All_Checks); |
fe48a434 | 5475 | |
38f5559f | 5476 | else |
5477 | return False; | |
5478 | end if; | |
ee6ba406 | 5479 | end Elaboration_Checks_Suppressed; |
5480 | ||
9dfe12ae | 5481 | --------------------------- |
5482 | -- Enable_Overflow_Check -- | |
5483 | --------------------------- | |
5484 | ||
5485 | procedure Enable_Overflow_Check (N : Node_Id) is | |
4c1c7f3f | 5486 | Typ : constant Entity_Id := Base_Type (Etype (N)); |
db415383 | 5487 | Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
3cce7f32 | 5488 | Chk : Nat; |
5489 | OK : Boolean; | |
5490 | Ent : Entity_Id; | |
5491 | Ofs : Uint; | |
5492 | Lo : Uint; | |
5493 | Hi : Uint; | |
ee6ba406 | 5494 | |
f3ccbbb3 | 5495 | Do_Ovflow_Check : Boolean; |
5496 | ||
ee6ba406 | 5497 | begin |
9dfe12ae | 5498 | if Debug_Flag_CC then |
5499 | w ("Enable_Overflow_Check for node ", Int (N)); | |
5500 | Write_Str (" Source location = "); | |
5501 | wl (Sloc (N)); | |
00c403ee | 5502 | pg (Union_Id (N)); |
ee6ba406 | 5503 | end if; |
ee6ba406 | 5504 | |
75209ec5 | 5505 | -- No check if overflow checks suppressed for type of node |
5506 | ||
0df9d43f | 5507 | if Overflow_Checks_Suppressed (Etype (N)) then |
75209ec5 | 5508 | return; |
5509 | ||
49260fa5 | 5510 | -- Nothing to do for unsigned integer types, which do not overflow |
5511 | ||
5512 | elsif Is_Modular_Integer_Type (Typ) then | |
5513 | return; | |
3cce7f32 | 5514 | end if; |
5515 | ||
0df9d43f | 5516 | -- This is the point at which processing for STRICT mode diverges |
21a55437 | 5517 | -- from processing for MINIMIZED/ELIMINATED modes. This divergence is |
5518 | -- probably more extreme that it needs to be, but what is going on here | |
5519 | -- is that when we introduced MINIMIZED/ELIMINATED modes, we wanted | |
0df9d43f | 5520 | -- to leave the processing for STRICT mode untouched. There were |
21a55437 | 5521 | -- two reasons for this. First it avoided any incompatible change of |
0df9d43f | 5522 | -- behavior. Second, it guaranteed that STRICT mode continued to be |
21a55437 | 5523 | -- legacy reliable. |
3cce7f32 | 5524 | |
0df9d43f | 5525 | -- The big difference is that in STRICT mode there is a fair amount of |
3cce7f32 | 5526 | -- circuitry to try to avoid setting the Do_Overflow_Check flag if we |
5527 | -- know that no check is needed. We skip all that in the two new modes, | |
5528 | -- since really overflow checking happens over a whole subtree, and we | |
5529 | -- do the corresponding optimizations later on when applying the checks. | |
5530 | ||
5531 | if Mode in Minimized_Or_Eliminated then | |
0df9d43f | 5532 | if not (Overflow_Checks_Suppressed (Etype (N))) |
5533 | and then not (Is_Entity_Name (N) | |
5534 | and then Overflow_Checks_Suppressed (Entity (N))) | |
5535 | then | |
5536 | Activate_Overflow_Check (N); | |
5537 | end if; | |
3cce7f32 | 5538 | |
5539 | if Debug_Flag_CC then | |
5540 | w ("Minimized/Eliminated mode"); | |
5541 | end if; | |
5542 | ||
5543 | return; | |
5544 | end if; | |
5545 | ||
0df9d43f | 5546 | -- Remainder of processing is for STRICT case, and is unchanged from |
691fe9e0 | 5547 | -- earlier versions preceding the addition of MINIMIZED/ELIMINATED. |
49260fa5 | 5548 | |
feff2f05 | 5549 | -- Nothing to do if the range of the result is known OK. We skip this |
5550 | -- for conversions, since the caller already did the check, and in any | |
5551 | -- case the condition for deleting the check for a type conversion is | |
cc60bd16 | 5552 | -- different. |
ee6ba406 | 5553 | |
3cce7f32 | 5554 | if Nkind (N) /= N_Type_Conversion then |
9c486805 | 5555 | Determine_Range (N, OK, Lo, Hi, Assume_Valid => True); |
ee6ba406 | 5556 | |
cc60bd16 | 5557 | -- Note in the test below that we assume that the range is not OK |
5558 | -- if a bound of the range is equal to that of the type. That's not | |
5559 | -- quite accurate but we do this for the following reasons: | |
ee6ba406 | 5560 | |
9dfe12ae | 5561 | -- a) The way that Determine_Range works, it will typically report |
5562 | -- the bounds of the value as being equal to the bounds of the | |
5563 | -- type, because it either can't tell anything more precise, or | |
5564 | -- does not think it is worth the effort to be more precise. | |
ee6ba406 | 5565 | |
9dfe12ae | 5566 | -- b) It is very unusual to have a situation in which this would |
5567 | -- generate an unnecessary overflow check (an example would be | |
5568 | -- a subtype with a range 0 .. Integer'Last - 1 to which the | |
cc60bd16 | 5569 | -- literal value one is added). |
ee6ba406 | 5570 | |
9dfe12ae | 5571 | -- c) The alternative is a lot of special casing in this routine |
5572 | -- which would partially duplicate Determine_Range processing. | |
ee6ba406 | 5573 | |
f3ccbbb3 | 5574 | if OK then |
5575 | Do_Ovflow_Check := True; | |
5576 | ||
5577 | -- Note that the following checks are quite deliberately > and < | |
5578 | -- rather than >= and <= as explained above. | |
5579 | ||
5580 | if Lo > Expr_Value (Type_Low_Bound (Typ)) | |
5581 | and then | |
5582 | Hi < Expr_Value (Type_High_Bound (Typ)) | |
5583 | then | |
5584 | Do_Ovflow_Check := False; | |
5585 | ||
5586 | -- Despite the comments above, it is worth dealing specially with | |
5587 | -- division specially. The only case where integer division can | |
5588 | -- overflow is (largest negative number) / (-1). So we will do | |
5589 | -- an extra range analysis to see if this is possible. | |
5590 | ||
5591 | elsif Nkind (N) = N_Op_Divide then | |
5592 | Determine_Range | |
5593 | (Left_Opnd (N), OK, Lo, Hi, Assume_Valid => True); | |
5594 | ||
5595 | if OK and then Lo > Expr_Value (Type_Low_Bound (Typ)) then | |
5596 | Do_Ovflow_Check := False; | |
5597 | ||
5598 | else | |
5599 | Determine_Range | |
5600 | (Right_Opnd (N), OK, Lo, Hi, Assume_Valid => True); | |
5601 | ||
5602 | if OK and then (Lo > Uint_Minus_1 | |
5603 | or else | |
5604 | Hi < Uint_Minus_1) | |
5605 | then | |
5606 | Do_Ovflow_Check := False; | |
5607 | end if; | |
5608 | end if; | |
9dfe12ae | 5609 | end if; |
5610 | ||
f3ccbbb3 | 5611 | -- If no overflow check required, we are done |
5612 | ||
5613 | if not Do_Ovflow_Check then | |
5614 | if Debug_Flag_CC then | |
5615 | w ("No overflow check required"); | |
5616 | end if; | |
5617 | ||
5618 | return; | |
5619 | end if; | |
9dfe12ae | 5620 | end if; |
5621 | end if; | |
5622 | ||
feff2f05 | 5623 | -- If not in optimizing mode, set flag and we are done. We are also done |
5624 | -- (and just set the flag) if the type is not a discrete type, since it | |
5625 | -- is not worth the effort to eliminate checks for other than discrete | |
5626 | -- types. In addition, we take this same path if we have stored the | |
5627 | -- maximum number of checks possible already (a very unlikely situation, | |
39a0c1d3 | 5628 | -- but we do not want to blow up). |
9dfe12ae | 5629 | |
5630 | if Optimization_Level = 0 | |
5631 | or else not Is_Discrete_Type (Etype (N)) | |
5632 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 5633 | then |
00c403ee | 5634 | Activate_Overflow_Check (N); |
9dfe12ae | 5635 | |
5636 | if Debug_Flag_CC then | |
5637 | w ("Optimization off"); | |
5638 | end if; | |
5639 | ||
ee6ba406 | 5640 | return; |
9dfe12ae | 5641 | end if; |
ee6ba406 | 5642 | |
9dfe12ae | 5643 | -- Otherwise evaluate and check the expression |
5644 | ||
5645 | Find_Check | |
5646 | (Expr => N, | |
5647 | Check_Type => 'O', | |
5648 | Target_Type => Empty, | |
5649 | Entry_OK => OK, | |
5650 | Check_Num => Chk, | |
5651 | Ent => Ent, | |
5652 | Ofs => Ofs); | |
5653 | ||
5654 | if Debug_Flag_CC then | |
5655 | w ("Called Find_Check"); | |
5656 | w (" OK = ", OK); | |
5657 | ||
5658 | if OK then | |
5659 | w (" Check_Num = ", Chk); | |
5660 | w (" Ent = ", Int (Ent)); | |
5661 | Write_Str (" Ofs = "); | |
5662 | pid (Ofs); | |
5663 | end if; | |
5664 | end if; | |
ee6ba406 | 5665 | |
9dfe12ae | 5666 | -- If check is not of form to optimize, then set flag and we are done |
5667 | ||
5668 | if not OK then | |
00c403ee | 5669 | Activate_Overflow_Check (N); |
ee6ba406 | 5670 | return; |
9dfe12ae | 5671 | end if; |
ee6ba406 | 5672 | |
9dfe12ae | 5673 | -- If check is already performed, then return without setting flag |
5674 | ||
5675 | if Chk /= 0 then | |
5676 | if Debug_Flag_CC then | |
5677 | w ("Check suppressed!"); | |
5678 | end if; | |
ee6ba406 | 5679 | |
ee6ba406 | 5680 | return; |
9dfe12ae | 5681 | end if; |
ee6ba406 | 5682 | |
9dfe12ae | 5683 | -- Here we will make a new entry for the new check |
5684 | ||
00c403ee | 5685 | Activate_Overflow_Check (N); |
9dfe12ae | 5686 | Num_Saved_Checks := Num_Saved_Checks + 1; |
5687 | Saved_Checks (Num_Saved_Checks) := | |
5688 | (Killed => False, | |
5689 | Entity => Ent, | |
5690 | Offset => Ofs, | |
5691 | Check_Type => 'O', | |
5692 | Target_Type => Empty); | |
5693 | ||
5694 | if Debug_Flag_CC then | |
5695 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
5696 | w (" Entity = ", Int (Ent)); | |
5697 | Write_Str (" Offset = "); | |
5698 | pid (Ofs); | |
5699 | w (" Check_Type = O"); | |
5700 | w (" Target_Type = Empty"); | |
5701 | end if; | |
ee6ba406 | 5702 | |
feff2f05 | 5703 | -- If we get an exception, then something went wrong, probably because of |
20cf157b | 5704 | -- an error in the structure of the tree due to an incorrect program. Or |
5705 | -- it may be a bug in the optimization circuit. In either case the safest | |
feff2f05 | 5706 | -- thing is simply to set the check flag unconditionally. |
9dfe12ae | 5707 | |
5708 | exception | |
5709 | when others => | |
00c403ee | 5710 | Activate_Overflow_Check (N); |
9dfe12ae | 5711 | |
5712 | if Debug_Flag_CC then | |
5713 | w (" exception occurred, overflow flag set"); | |
5714 | end if; | |
5715 | ||
5716 | return; | |
5717 | end Enable_Overflow_Check; | |
5718 | ||
5719 | ------------------------ | |
5720 | -- Enable_Range_Check -- | |
5721 | ------------------------ | |
5722 | ||
5723 | procedure Enable_Range_Check (N : Node_Id) is | |
5724 | Chk : Nat; | |
5725 | OK : Boolean; | |
5726 | Ent : Entity_Id; | |
5727 | Ofs : Uint; | |
5728 | Ttyp : Entity_Id; | |
5729 | P : Node_Id; | |
5730 | ||
5731 | begin | |
feff2f05 | 5732 | -- Return if unchecked type conversion with range check killed. In this |
39a0c1d3 | 5733 | -- case we never set the flag (that's what Kill_Range_Check is about). |
9dfe12ae | 5734 | |
5735 | if Nkind (N) = N_Unchecked_Type_Conversion | |
5736 | and then Kill_Range_Check (N) | |
ee6ba406 | 5737 | then |
5738 | return; | |
9dfe12ae | 5739 | end if; |
ee6ba406 | 5740 | |
55e8372b | 5741 | -- Do not set range check flag if parent is assignment statement or |
5742 | -- object declaration with Suppress_Assignment_Checks flag set | |
5743 | ||
5744 | if Nkind_In (Parent (N), N_Assignment_Statement, N_Object_Declaration) | |
5745 | and then Suppress_Assignment_Checks (Parent (N)) | |
5746 | then | |
5747 | return; | |
5748 | end if; | |
5749 | ||
0577b0b1 | 5750 | -- Check for various cases where we should suppress the range check |
5751 | ||
5752 | -- No check if range checks suppressed for type of node | |
5753 | ||
20cf157b | 5754 | if Present (Etype (N)) and then Range_Checks_Suppressed (Etype (N)) then |
0577b0b1 | 5755 | return; |
5756 | ||
5757 | -- No check if node is an entity name, and range checks are suppressed | |
5758 | -- for this entity, or for the type of this entity. | |
5759 | ||
5760 | elsif Is_Entity_Name (N) | |
5761 | and then (Range_Checks_Suppressed (Entity (N)) | |
20cf157b | 5762 | or else Range_Checks_Suppressed (Etype (Entity (N)))) |
0577b0b1 | 5763 | then |
5764 | return; | |
5765 | ||
5766 | -- No checks if index of array, and index checks are suppressed for | |
5767 | -- the array object or the type of the array. | |
5768 | ||
5769 | elsif Nkind (Parent (N)) = N_Indexed_Component then | |
5770 | declare | |
5771 | Pref : constant Node_Id := Prefix (Parent (N)); | |
5772 | begin | |
5773 | if Is_Entity_Name (Pref) | |
5774 | and then Index_Checks_Suppressed (Entity (Pref)) | |
5775 | then | |
5776 | return; | |
5777 | elsif Index_Checks_Suppressed (Etype (Pref)) then | |
5778 | return; | |
5779 | end if; | |
5780 | end; | |
5781 | end if; | |
5782 | ||
9dfe12ae | 5783 | -- Debug trace output |
ee6ba406 | 5784 | |
9dfe12ae | 5785 | if Debug_Flag_CC then |
5786 | w ("Enable_Range_Check for node ", Int (N)); | |
5787 | Write_Str (" Source location = "); | |
5788 | wl (Sloc (N)); | |
00c403ee | 5789 | pg (Union_Id (N)); |
9dfe12ae | 5790 | end if; |
5791 | ||
feff2f05 | 5792 | -- If not in optimizing mode, set flag and we are done. We are also done |
5793 | -- (and just set the flag) if the type is not a discrete type, since it | |
5794 | -- is not worth the effort to eliminate checks for other than discrete | |
5795 | -- types. In addition, we take this same path if we have stored the | |
5796 | -- maximum number of checks possible already (a very unlikely situation, | |
39a0c1d3 | 5797 | -- but we do not want to blow up). |
9dfe12ae | 5798 | |
5799 | if Optimization_Level = 0 | |
5800 | or else No (Etype (N)) | |
5801 | or else not Is_Discrete_Type (Etype (N)) | |
5802 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 5803 | then |
00c403ee | 5804 | Activate_Range_Check (N); |
9dfe12ae | 5805 | |
5806 | if Debug_Flag_CC then | |
5807 | w ("Optimization off"); | |
5808 | end if; | |
5809 | ||
ee6ba406 | 5810 | return; |
9dfe12ae | 5811 | end if; |
ee6ba406 | 5812 | |
9dfe12ae | 5813 | -- Otherwise find out the target type |
ee6ba406 | 5814 | |
9dfe12ae | 5815 | P := Parent (N); |
ee6ba406 | 5816 | |
9dfe12ae | 5817 | -- For assignment, use left side subtype |
5818 | ||
5819 | if Nkind (P) = N_Assignment_Statement | |
5820 | and then Expression (P) = N | |
5821 | then | |
5822 | Ttyp := Etype (Name (P)); | |
5823 | ||
5824 | -- For indexed component, use subscript subtype | |
5825 | ||
5826 | elsif Nkind (P) = N_Indexed_Component then | |
5827 | declare | |
5828 | Atyp : Entity_Id; | |
5829 | Indx : Node_Id; | |
5830 | Subs : Node_Id; | |
5831 | ||
5832 | begin | |
5833 | Atyp := Etype (Prefix (P)); | |
5834 | ||
5835 | if Is_Access_Type (Atyp) then | |
5836 | Atyp := Designated_Type (Atyp); | |
f07ea091 | 5837 | |
5838 | -- If the prefix is an access to an unconstrained array, | |
feff2f05 | 5839 | -- perform check unconditionally: it depends on the bounds of |
5840 | -- an object and we cannot currently recognize whether the test | |
5841 | -- may be redundant. | |
f07ea091 | 5842 | |
5843 | if not Is_Constrained (Atyp) then | |
00c403ee | 5844 | Activate_Range_Check (N); |
f07ea091 | 5845 | return; |
5846 | end if; | |
7189d17f | 5847 | |
31831d39 | 5848 | -- Ditto if prefix is simply an unconstrained array. We used |
5849 | -- to think this case was OK, if the prefix was not an explicit | |
5850 | -- dereference, but we have now seen a case where this is not | |
5851 | -- true, so it is safer to just suppress the optimization in this | |
5852 | -- case. The back end is getting better at eliminating redundant | |
5853 | -- checks in any case, so the loss won't be important. | |
7189d17f | 5854 | |
31831d39 | 5855 | elsif Is_Array_Type (Atyp) |
7189d17f | 5856 | and then not Is_Constrained (Atyp) |
5857 | then | |
00c403ee | 5858 | Activate_Range_Check (N); |
7189d17f | 5859 | return; |
9dfe12ae | 5860 | end if; |
5861 | ||
5862 | Indx := First_Index (Atyp); | |
5863 | Subs := First (Expressions (P)); | |
5864 | loop | |
5865 | if Subs = N then | |
5866 | Ttyp := Etype (Indx); | |
5867 | exit; | |
5868 | end if; | |
5869 | ||
5870 | Next_Index (Indx); | |
5871 | Next (Subs); | |
5872 | end loop; | |
5873 | end; | |
5874 | ||
5875 | -- For now, ignore all other cases, they are not so interesting | |
5876 | ||
5877 | else | |
5878 | if Debug_Flag_CC then | |
5879 | w (" target type not found, flag set"); | |
5880 | end if; | |
5881 | ||
00c403ee | 5882 | Activate_Range_Check (N); |
9dfe12ae | 5883 | return; |
5884 | end if; | |
5885 | ||
5886 | -- Evaluate and check the expression | |
5887 | ||
5888 | Find_Check | |
5889 | (Expr => N, | |
5890 | Check_Type => 'R', | |
5891 | Target_Type => Ttyp, | |
5892 | Entry_OK => OK, | |
5893 | Check_Num => Chk, | |
5894 | Ent => Ent, | |
5895 | Ofs => Ofs); | |
5896 | ||
5897 | if Debug_Flag_CC then | |
5898 | w ("Called Find_Check"); | |
5899 | w ("Target_Typ = ", Int (Ttyp)); | |
5900 | w (" OK = ", OK); | |
5901 | ||
5902 | if OK then | |
5903 | w (" Check_Num = ", Chk); | |
5904 | w (" Ent = ", Int (Ent)); | |
5905 | Write_Str (" Ofs = "); | |
5906 | pid (Ofs); | |
5907 | end if; | |
5908 | end if; | |
5909 | ||
5910 | -- If check is not of form to optimize, then set flag and we are done | |
5911 | ||
5912 | if not OK then | |
5913 | if Debug_Flag_CC then | |
5914 | w (" expression not of optimizable type, flag set"); | |
5915 | end if; | |
5916 | ||
00c403ee | 5917 | Activate_Range_Check (N); |
9dfe12ae | 5918 | return; |
5919 | end if; | |
5920 | ||
5921 | -- If check is already performed, then return without setting flag | |
5922 | ||
5923 | if Chk /= 0 then | |
5924 | if Debug_Flag_CC then | |
5925 | w ("Check suppressed!"); | |
5926 | end if; | |
5927 | ||
5928 | return; | |
5929 | end if; | |
5930 | ||
5931 | -- Here we will make a new entry for the new check | |
5932 | ||
00c403ee | 5933 | Activate_Range_Check (N); |
9dfe12ae | 5934 | Num_Saved_Checks := Num_Saved_Checks + 1; |
5935 | Saved_Checks (Num_Saved_Checks) := | |
5936 | (Killed => False, | |
5937 | Entity => Ent, | |
5938 | Offset => Ofs, | |
5939 | Check_Type => 'R', | |
5940 | Target_Type => Ttyp); | |
5941 | ||
5942 | if Debug_Flag_CC then | |
5943 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
5944 | w (" Entity = ", Int (Ent)); | |
5945 | Write_Str (" Offset = "); | |
5946 | pid (Ofs); | |
5947 | w (" Check_Type = R"); | |
5948 | w (" Target_Type = ", Int (Ttyp)); | |
00c403ee | 5949 | pg (Union_Id (Ttyp)); |
9dfe12ae | 5950 | end if; |
5951 | ||
feff2f05 | 5952 | -- If we get an exception, then something went wrong, probably because of |
5953 | -- an error in the structure of the tree due to an incorrect program. Or | |
5954 | -- it may be a bug in the optimization circuit. In either case the safest | |
5955 | -- thing is simply to set the check flag unconditionally. | |
9dfe12ae | 5956 | |
5957 | exception | |
5958 | when others => | |
00c403ee | 5959 | Activate_Range_Check (N); |
9dfe12ae | 5960 | |
5961 | if Debug_Flag_CC then | |
5962 | w (" exception occurred, range flag set"); | |
5963 | end if; | |
5964 | ||
5965 | return; | |
5966 | end Enable_Range_Check; | |
5967 | ||
5968 | ------------------ | |
5969 | -- Ensure_Valid -- | |
5970 | ------------------ | |
5971 | ||
aaec8d13 | 5972 | procedure Ensure_Valid |
5973 | (Expr : Node_Id; | |
5974 | Holes_OK : Boolean := False; | |
5975 | Related_Id : Entity_Id := Empty; | |
5976 | Is_Low_Bound : Boolean := False; | |
5977 | Is_High_Bound : Boolean := False) | |
5978 | is | |
9dfe12ae | 5979 | Typ : constant Entity_Id := Etype (Expr); |
5980 | ||
5981 | begin | |
5982 | -- Ignore call if we are not doing any validity checking | |
5983 | ||
5984 | if not Validity_Checks_On then | |
5985 | return; | |
5986 | ||
0577b0b1 | 5987 | -- Ignore call if range or validity checks suppressed on entity or type |
9dfe12ae | 5988 | |
0577b0b1 | 5989 | elsif Range_Or_Validity_Checks_Suppressed (Expr) then |
9dfe12ae | 5990 | return; |
5991 | ||
feff2f05 | 5992 | -- No check required if expression is from the expander, we assume the |
5993 | -- expander will generate whatever checks are needed. Note that this is | |
39a0c1d3 | 5994 | -- not just an optimization, it avoids infinite recursions. |
9dfe12ae | 5995 | |
5996 | -- Unchecked conversions must be checked, unless they are initialized | |
5997 | -- scalar values, as in a component assignment in an init proc. | |
5998 | ||
5999 | -- In addition, we force a check if Force_Validity_Checks is set | |
6000 | ||
6001 | elsif not Comes_From_Source (Expr) | |
404eb7da | 6002 | and then not |
6003 | (Nkind (Expr) = N_Identifier | |
6004 | and then Present (Renamed_Object (Entity (Expr))) | |
6005 | and then Comes_From_Source (Renamed_Object (Entity (Expr)))) | |
9dfe12ae | 6006 | and then not Force_Validity_Checks |
6007 | and then (Nkind (Expr) /= N_Unchecked_Type_Conversion | |
6008 | or else Kill_Range_Check (Expr)) | |
6009 | then | |
6010 | return; | |
6011 | ||
6012 | -- No check required if expression is known to have valid value | |
6013 | ||
6014 | elsif Expr_Known_Valid (Expr) then | |
6015 | return; | |
6016 | ||
ea1f4b87 | 6017 | -- No check needed within a generated predicate function. Validity |
6018 | -- of input value will have been checked earlier. | |
6019 | ||
6020 | elsif Ekind (Current_Scope) = E_Function | |
6021 | and then Is_Predicate_Function (Current_Scope) | |
6022 | then | |
6023 | return; | |
6024 | ||
feff2f05 | 6025 | -- Ignore case of enumeration with holes where the flag is set not to |
6026 | -- worry about holes, since no special validity check is needed | |
9dfe12ae | 6027 | |
6028 | elsif Is_Enumeration_Type (Typ) | |
6029 | and then Has_Non_Standard_Rep (Typ) | |
6030 | and then Holes_OK | |
6031 | then | |
6032 | return; | |
6033 | ||
f2a06be9 | 6034 | -- No check required on the left-hand side of an assignment |
9dfe12ae | 6035 | |
6036 | elsif Nkind (Parent (Expr)) = N_Assignment_Statement | |
6037 | and then Expr = Name (Parent (Expr)) | |
6038 | then | |
6039 | return; | |
6040 | ||
6fb3c314 | 6041 | -- No check on a universal real constant. The context will eventually |
38f5559f | 6042 | -- convert it to a machine number for some target type, or report an |
6043 | -- illegality. | |
6044 | ||
6045 | elsif Nkind (Expr) = N_Real_Literal | |
6046 | and then Etype (Expr) = Universal_Real | |
6047 | then | |
6048 | return; | |
6049 | ||
6fb3c314 | 6050 | -- If the expression denotes a component of a packed boolean array, |
0577b0b1 | 6051 | -- no possible check applies. We ignore the old ACATS chestnuts that |
6052 | -- involve Boolean range True..True. | |
6053 | ||
6054 | -- Note: validity checks are generated for expressions that yield a | |
6055 | -- scalar type, when it is possible to create a value that is outside of | |
6056 | -- the type. If this is a one-bit boolean no such value exists. This is | |
6057 | -- an optimization, and it also prevents compiler blowing up during the | |
6058 | -- elaboration of improperly expanded packed array references. | |
6059 | ||
6060 | elsif Nkind (Expr) = N_Indexed_Component | |
6061 | and then Is_Bit_Packed_Array (Etype (Prefix (Expr))) | |
6062 | and then Root_Type (Etype (Expr)) = Standard_Boolean | |
6063 | then | |
6064 | return; | |
6065 | ||
737e8460 | 6066 | -- For an expression with actions, we want to insert the validity check |
6067 | -- on the final Expression. | |
6068 | ||
6069 | elsif Nkind (Expr) = N_Expression_With_Actions then | |
6070 | Ensure_Valid (Expression (Expr)); | |
6071 | return; | |
6072 | ||
9dfe12ae | 6073 | -- An annoying special case. If this is an out parameter of a scalar |
6074 | -- type, then the value is not going to be accessed, therefore it is | |
becb6111 | 6075 | -- inappropriate to do any validity check at the call site. Likewise |
6076 | -- if the parameter is passed by reference. | |
9dfe12ae | 6077 | |
6078 | else | |
6079 | -- Only need to worry about scalar types | |
6080 | ||
6081 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 6082 | declare |
6083 | P : Node_Id; | |
6084 | N : Node_Id; | |
6085 | E : Entity_Id; | |
6086 | F : Entity_Id; | |
6087 | A : Node_Id; | |
6088 | L : List_Id; | |
6089 | ||
6090 | begin | |
6091 | -- Find actual argument (which may be a parameter association) | |
6092 | -- and the parent of the actual argument (the call statement) | |
6093 | ||
6094 | N := Expr; | |
6095 | P := Parent (Expr); | |
6096 | ||
6097 | if Nkind (P) = N_Parameter_Association then | |
6098 | N := P; | |
6099 | P := Parent (N); | |
6100 | end if; | |
6101 | ||
becb6111 | 6102 | -- If this is an indirect or dispatching call, get signature |
6103 | -- from the subprogram type. | |
ee6ba406 | 6104 | |
becb6111 | 6105 | if Nkind_In (P, N_Entry_Call_Statement, |
6106 | N_Function_Call, | |
6107 | N_Procedure_Call_Statement) | |
6108 | then | |
6109 | E := Get_Called_Entity (P); | |
ee6ba406 | 6110 | L := Parameter_Associations (P); |
9dfe12ae | 6111 | |
feff2f05 | 6112 | -- Only need to worry if there are indeed actuals, and if |
becb6111 | 6113 | -- this could be a subprogram call, otherwise we cannot get |
6114 | -- a match (either we are not an argument, or the mode of | |
6115 | -- the formal is not OUT). This test also filters out the | |
feff2f05 | 6116 | -- generic case. |
ee6ba406 | 6117 | |
20cf157b | 6118 | if Is_Non_Empty_List (L) and then Is_Subprogram (E) then |
6119 | ||
feff2f05 | 6120 | -- This is the loop through parameters, looking for an |
6121 | -- OUT parameter for which we are the argument. | |
ee6ba406 | 6122 | |
6123 | F := First_Formal (E); | |
6124 | A := First (L); | |
ee6ba406 | 6125 | while Present (F) loop |
becb6111 | 6126 | if A = N |
6127 | and then (Ekind (F) = E_Out_Parameter | |
6128 | or else Mechanism (F) = By_Reference) | |
6129 | then | |
ee6ba406 | 6130 | return; |
6131 | end if; | |
6132 | ||
6133 | Next_Formal (F); | |
6134 | Next (A); | |
6135 | end loop; | |
6136 | end if; | |
6137 | end if; | |
6138 | end; | |
6139 | end if; | |
6140 | end if; | |
6141 | ||
fa6a6949 | 6142 | -- If this is a boolean expression, only its elementary operands need |
90a07d4c | 6143 | -- checking: if they are valid, a boolean or short-circuit operation |
6144 | -- with them will be valid as well. | |
784d4230 | 6145 | |
6146 | if Base_Type (Typ) = Standard_Boolean | |
7af38999 | 6147 | and then |
fa6a6949 | 6148 | (Nkind (Expr) in N_Op or else Nkind (Expr) in N_Short_Circuit) |
784d4230 | 6149 | then |
6150 | return; | |
6151 | end if; | |
6152 | ||
0577b0b1 | 6153 | -- If we fall through, a validity check is required |
ee6ba406 | 6154 | |
aaec8d13 | 6155 | Insert_Valid_Check (Expr, Related_Id, Is_Low_Bound, Is_High_Bound); |
ce7498d3 | 6156 | |
6157 | if Is_Entity_Name (Expr) | |
6158 | and then Safe_To_Capture_Value (Expr, Entity (Expr)) | |
6159 | then | |
6160 | Set_Is_Known_Valid (Entity (Expr)); | |
6161 | end if; | |
ee6ba406 | 6162 | end Ensure_Valid; |
6163 | ||
6164 | ---------------------- | |
6165 | -- Expr_Known_Valid -- | |
6166 | ---------------------- | |
6167 | ||
6168 | function Expr_Known_Valid (Expr : Node_Id) return Boolean is | |
6169 | Typ : constant Entity_Id := Etype (Expr); | |
6170 | ||
6171 | begin | |
feff2f05 | 6172 | -- Non-scalar types are always considered valid, since they never give |
6173 | -- rise to the issues of erroneous or bounded error behavior that are | |
6174 | -- the concern. In formal reference manual terms the notion of validity | |
6175 | -- only applies to scalar types. Note that even when packed arrays are | |
6176 | -- represented using modular types, they are still arrays semantically, | |
6177 | -- so they are also always valid (in particular, the unused bits can be | |
6178 | -- random rubbish without affecting the validity of the array value). | |
ee6ba406 | 6179 | |
a88a5773 | 6180 | if not Is_Scalar_Type (Typ) or else Is_Packed_Array_Impl_Type (Typ) then |
ee6ba406 | 6181 | return True; |
6182 | ||
6183 | -- If no validity checking, then everything is considered valid | |
6184 | ||
6185 | elsif not Validity_Checks_On then | |
6186 | return True; | |
6187 | ||
6188 | -- Floating-point types are considered valid unless floating-point | |
6189 | -- validity checks have been specifically turned on. | |
6190 | ||
6191 | elsif Is_Floating_Point_Type (Typ) | |
6192 | and then not Validity_Check_Floating_Point | |
6193 | then | |
6194 | return True; | |
6195 | ||
feff2f05 | 6196 | -- If the expression is the value of an object that is known to be |
6197 | -- valid, then clearly the expression value itself is valid. | |
ee6ba406 | 6198 | |
6199 | elsif Is_Entity_Name (Expr) | |
6200 | and then Is_Known_Valid (Entity (Expr)) | |
985fe5d6 | 6201 | |
6202 | -- Exclude volatile variables | |
6203 | ||
6204 | and then not Treat_As_Volatile (Entity (Expr)) | |
ee6ba406 | 6205 | then |
6206 | return True; | |
6207 | ||
0577b0b1 | 6208 | -- References to discriminants are always considered valid. The value |
6209 | -- of a discriminant gets checked when the object is built. Within the | |
6210 | -- record, we consider it valid, and it is important to do so, since | |
6211 | -- otherwise we can try to generate bogus validity checks which | |
feff2f05 | 6212 | -- reference discriminants out of scope. Discriminants of concurrent |
6213 | -- types are excluded for the same reason. | |
0577b0b1 | 6214 | |
6215 | elsif Is_Entity_Name (Expr) | |
feff2f05 | 6216 | and then Denotes_Discriminant (Expr, Check_Concurrent => True) |
0577b0b1 | 6217 | then |
6218 | return True; | |
6219 | ||
feff2f05 | 6220 | -- If the type is one for which all values are known valid, then we are |
6221 | -- sure that the value is valid except in the slightly odd case where | |
6222 | -- the expression is a reference to a variable whose size has been | |
6223 | -- explicitly set to a value greater than the object size. | |
ee6ba406 | 6224 | |
6225 | elsif Is_Known_Valid (Typ) then | |
6226 | if Is_Entity_Name (Expr) | |
6227 | and then Ekind (Entity (Expr)) = E_Variable | |
6228 | and then Esize (Entity (Expr)) > Esize (Typ) | |
6229 | then | |
6230 | return False; | |
6231 | else | |
6232 | return True; | |
6233 | end if; | |
6234 | ||
6235 | -- Integer and character literals always have valid values, where | |
6236 | -- appropriate these will be range checked in any case. | |
6237 | ||
20cf157b | 6238 | elsif Nkind_In (Expr, N_Integer_Literal, N_Character_Literal) then |
ee6ba406 | 6239 | return True; |
91e47010 | 6240 | |
ee6ba406 | 6241 | -- If we have a type conversion or a qualification of a known valid |
6242 | -- value, then the result will always be valid. | |
6243 | ||
20cf157b | 6244 | elsif Nkind_In (Expr, N_Type_Conversion, N_Qualified_Expression) then |
ee6ba406 | 6245 | return Expr_Known_Valid (Expression (Expr)); |
6246 | ||
1eb1395f | 6247 | -- Case of expression is a non-floating-point operator. In this case we |
6248 | -- can assume the result is valid the generated code for the operator | |
6249 | -- will include whatever checks are needed (e.g. range checks) to ensure | |
6250 | -- validity. This assumption does not hold for the floating-point case, | |
6251 | -- since floating-point operators can generate Infinite or NaN results | |
6252 | -- which are considered invalid. | |
6253 | ||
6254 | -- Historical note: in older versions, the exemption of floating-point | |
6255 | -- types from this assumption was done only in cases where the parent | |
6256 | -- was an assignment, function call or parameter association. Presumably | |
6257 | -- the idea was that in other contexts, the result would be checked | |
6258 | -- elsewhere, but this list of cases was missing tests (at least the | |
6259 | -- N_Object_Declaration case, as shown by a reported missing validity | |
6260 | -- check), and it is not clear why function calls but not procedure | |
6261 | -- calls were tested for. It really seems more accurate and much | |
6262 | -- safer to recognize that expressions which are the result of a | |
6263 | -- floating-point operator can never be assumed to be valid. | |
6264 | ||
6265 | elsif Nkind (Expr) in N_Op and then not Is_Floating_Point_Type (Typ) then | |
6266 | return True; | |
1d90d657 | 6267 | |
feff2f05 | 6268 | -- The result of a membership test is always valid, since it is true or |
6269 | -- false, there are no other possibilities. | |
0577b0b1 | 6270 | |
6271 | elsif Nkind (Expr) in N_Membership_Test then | |
6272 | return True; | |
6273 | ||
ee6ba406 | 6274 | -- For all other cases, we do not know the expression is valid |
6275 | ||
6276 | else | |
6277 | return False; | |
6278 | end if; | |
6279 | end Expr_Known_Valid; | |
6280 | ||
9dfe12ae | 6281 | ---------------- |
6282 | -- Find_Check -- | |
6283 | ---------------- | |
6284 | ||
6285 | procedure Find_Check | |
6286 | (Expr : Node_Id; | |
6287 | Check_Type : Character; | |
6288 | Target_Type : Entity_Id; | |
6289 | Entry_OK : out Boolean; | |
6290 | Check_Num : out Nat; | |
6291 | Ent : out Entity_Id; | |
6292 | Ofs : out Uint) | |
6293 | is | |
6294 | function Within_Range_Of | |
6295 | (Target_Type : Entity_Id; | |
314a23b6 | 6296 | Check_Type : Entity_Id) return Boolean; |
9dfe12ae | 6297 | -- Given a requirement for checking a range against Target_Type, and |
6298 | -- and a range Check_Type against which a check has already been made, | |
6299 | -- determines if the check against check type is sufficient to ensure | |
6300 | -- that no check against Target_Type is required. | |
6301 | ||
6302 | --------------------- | |
6303 | -- Within_Range_Of -- | |
6304 | --------------------- | |
6305 | ||
6306 | function Within_Range_Of | |
6307 | (Target_Type : Entity_Id; | |
314a23b6 | 6308 | Check_Type : Entity_Id) return Boolean |
9dfe12ae | 6309 | is |
6310 | begin | |
6311 | if Target_Type = Check_Type then | |
6312 | return True; | |
6313 | ||
6314 | else | |
6315 | declare | |
6316 | Tlo : constant Node_Id := Type_Low_Bound (Target_Type); | |
6317 | Thi : constant Node_Id := Type_High_Bound (Target_Type); | |
6318 | Clo : constant Node_Id := Type_Low_Bound (Check_Type); | |
6319 | Chi : constant Node_Id := Type_High_Bound (Check_Type); | |
6320 | ||
6321 | begin | |
6322 | if (Tlo = Clo | |
6323 | or else (Compile_Time_Known_Value (Tlo) | |
6324 | and then | |
6325 | Compile_Time_Known_Value (Clo) | |
6326 | and then | |
6327 | Expr_Value (Clo) >= Expr_Value (Tlo))) | |
6328 | and then | |
6329 | (Thi = Chi | |
6330 | or else (Compile_Time_Known_Value (Thi) | |
6331 | and then | |
6332 | Compile_Time_Known_Value (Chi) | |
6333 | and then | |
6334 | Expr_Value (Chi) <= Expr_Value (Clo))) | |
6335 | then | |
6336 | return True; | |
6337 | else | |
6338 | return False; | |
6339 | end if; | |
6340 | end; | |
6341 | end if; | |
6342 | end Within_Range_Of; | |
6343 | ||
6344 | -- Start of processing for Find_Check | |
6345 | ||
6346 | begin | |
ed195555 | 6347 | -- Establish default, in case no entry is found |
9dfe12ae | 6348 | |
6349 | Check_Num := 0; | |
6350 | ||
6351 | -- Case of expression is simple entity reference | |
6352 | ||
6353 | if Is_Entity_Name (Expr) then | |
6354 | Ent := Entity (Expr); | |
6355 | Ofs := Uint_0; | |
6356 | ||
6357 | -- Case of expression is entity + known constant | |
6358 | ||
6359 | elsif Nkind (Expr) = N_Op_Add | |
6360 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
6361 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
6362 | then | |
6363 | Ent := Entity (Left_Opnd (Expr)); | |
6364 | Ofs := Expr_Value (Right_Opnd (Expr)); | |
6365 | ||
6366 | -- Case of expression is entity - known constant | |
6367 | ||
6368 | elsif Nkind (Expr) = N_Op_Subtract | |
6369 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
6370 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
6371 | then | |
6372 | Ent := Entity (Left_Opnd (Expr)); | |
6373 | Ofs := UI_Negate (Expr_Value (Right_Opnd (Expr))); | |
6374 | ||
6375 | -- Any other expression is not of the right form | |
6376 | ||
6377 | else | |
6378 | Ent := Empty; | |
6379 | Ofs := Uint_0; | |
6380 | Entry_OK := False; | |
6381 | return; | |
6382 | end if; | |
6383 | ||
feff2f05 | 6384 | -- Come here with expression of appropriate form, check if entity is an |
6385 | -- appropriate one for our purposes. | |
9dfe12ae | 6386 | |
6387 | if (Ekind (Ent) = E_Variable | |
cc60bd16 | 6388 | or else Is_Constant_Object (Ent)) |
9dfe12ae | 6389 | and then not Is_Library_Level_Entity (Ent) |
6390 | then | |
6391 | Entry_OK := True; | |
6392 | else | |
6393 | Entry_OK := False; | |
6394 | return; | |
6395 | end if; | |
6396 | ||
6397 | -- See if there is matching check already | |
6398 | ||
6399 | for J in reverse 1 .. Num_Saved_Checks loop | |
6400 | declare | |
6401 | SC : Saved_Check renames Saved_Checks (J); | |
9dfe12ae | 6402 | begin |
6403 | if SC.Killed = False | |
6404 | and then SC.Entity = Ent | |
6405 | and then SC.Offset = Ofs | |
6406 | and then SC.Check_Type = Check_Type | |
6407 | and then Within_Range_Of (Target_Type, SC.Target_Type) | |
6408 | then | |
6409 | Check_Num := J; | |
6410 | return; | |
6411 | end if; | |
6412 | end; | |
6413 | end loop; | |
6414 | ||
6415 | -- If we fall through entry was not found | |
6416 | ||
9dfe12ae | 6417 | return; |
6418 | end Find_Check; | |
6419 | ||
6420 | --------------------------------- | |
6421 | -- Generate_Discriminant_Check -- | |
6422 | --------------------------------- | |
6423 | ||
6424 | -- Note: the code for this procedure is derived from the | |
feff2f05 | 6425 | -- Emit_Discriminant_Check Routine in trans.c. |
9dfe12ae | 6426 | |
6427 | procedure Generate_Discriminant_Check (N : Node_Id) is | |
6428 | Loc : constant Source_Ptr := Sloc (N); | |
6429 | Pref : constant Node_Id := Prefix (N); | |
6430 | Sel : constant Node_Id := Selector_Name (N); | |
6431 | ||
6432 | Orig_Comp : constant Entity_Id := | |
b6341c67 | 6433 | Original_Record_Component (Entity (Sel)); |
9dfe12ae | 6434 | -- The original component to be checked |
6435 | ||
6436 | Discr_Fct : constant Entity_Id := | |
b6341c67 | 6437 | Discriminant_Checking_Func (Orig_Comp); |
9dfe12ae | 6438 | -- The discriminant checking function |
6439 | ||
6440 | Discr : Entity_Id; | |
6441 | -- One discriminant to be checked in the type | |
6442 | ||
6443 | Real_Discr : Entity_Id; | |
6444 | -- Actual discriminant in the call | |
6445 | ||
6446 | Pref_Type : Entity_Id; | |
6447 | -- Type of relevant prefix (ignoring private/access stuff) | |
6448 | ||
6449 | Args : List_Id; | |
6450 | -- List of arguments for function call | |
6451 | ||
6452 | Formal : Entity_Id; | |
feff2f05 | 6453 | -- Keep track of the formal corresponding to the actual we build for |
6454 | -- each discriminant, in order to be able to perform the necessary type | |
6455 | -- conversions. | |
9dfe12ae | 6456 | |
6457 | Scomp : Node_Id; | |
6458 | -- Selected component reference for checking function argument | |
6459 | ||
6460 | begin | |
6461 | Pref_Type := Etype (Pref); | |
6462 | ||
6463 | -- Force evaluation of the prefix, so that it does not get evaluated | |
6464 | -- twice (once for the check, once for the actual reference). Such a | |
20cf157b | 6465 | -- double evaluation is always a potential source of inefficiency, and |
6466 | -- is functionally incorrect in the volatile case, or when the prefix | |
f9906591 | 6467 | -- may have side effects. A nonvolatile entity or a component of a |
6468 | -- nonvolatile entity requires no evaluation. | |
9dfe12ae | 6469 | |
6470 | if Is_Entity_Name (Pref) then | |
6471 | if Treat_As_Volatile (Entity (Pref)) then | |
6472 | Force_Evaluation (Pref, Name_Req => True); | |
6473 | end if; | |
6474 | ||
6475 | elsif Treat_As_Volatile (Etype (Pref)) then | |
20cf157b | 6476 | Force_Evaluation (Pref, Name_Req => True); |
9dfe12ae | 6477 | |
6478 | elsif Nkind (Pref) = N_Selected_Component | |
6479 | and then Is_Entity_Name (Prefix (Pref)) | |
6480 | then | |
6481 | null; | |
6482 | ||
6483 | else | |
6484 | Force_Evaluation (Pref, Name_Req => True); | |
6485 | end if; | |
6486 | ||
6487 | -- For a tagged type, use the scope of the original component to | |
6488 | -- obtain the type, because ??? | |
6489 | ||
6490 | if Is_Tagged_Type (Scope (Orig_Comp)) then | |
6491 | Pref_Type := Scope (Orig_Comp); | |
6492 | ||
feff2f05 | 6493 | -- For an untagged derived type, use the discriminants of the parent |
6494 | -- which have been renamed in the derivation, possibly by a one-to-many | |
d1a2e31b | 6495 | -- discriminant constraint. For untagged type, initially get the Etype |
feff2f05 | 6496 | -- of the prefix |
9dfe12ae | 6497 | |
6498 | else | |
6499 | if Is_Derived_Type (Pref_Type) | |
6500 | and then Number_Discriminants (Pref_Type) /= | |
6501 | Number_Discriminants (Etype (Base_Type (Pref_Type))) | |
6502 | then | |
6503 | Pref_Type := Etype (Base_Type (Pref_Type)); | |
6504 | end if; | |
6505 | end if; | |
6506 | ||
6507 | -- We definitely should have a checking function, This routine should | |
6508 | -- not be called if no discriminant checking function is present. | |
6509 | ||
6510 | pragma Assert (Present (Discr_Fct)); | |
6511 | ||
6512 | -- Create the list of the actual parameters for the call. This list | |
6513 | -- is the list of the discriminant fields of the record expression to | |
6514 | -- be discriminant checked. | |
6515 | ||
6516 | Args := New_List; | |
6517 | Formal := First_Formal (Discr_Fct); | |
6518 | Discr := First_Discriminant (Pref_Type); | |
6519 | while Present (Discr) loop | |
6520 | ||
6521 | -- If we have a corresponding discriminant field, and a parent | |
6522 | -- subtype is present, then we want to use the corresponding | |
6523 | -- discriminant since this is the one with the useful value. | |
6524 | ||
6525 | if Present (Corresponding_Discriminant (Discr)) | |
6526 | and then Ekind (Pref_Type) = E_Record_Type | |
6527 | and then Present (Parent_Subtype (Pref_Type)) | |
6528 | then | |
6529 | Real_Discr := Corresponding_Discriminant (Discr); | |
6530 | else | |
6531 | Real_Discr := Discr; | |
6532 | end if; | |
6533 | ||
6534 | -- Construct the reference to the discriminant | |
6535 | ||
6536 | Scomp := | |
6537 | Make_Selected_Component (Loc, | |
6538 | Prefix => | |
6539 | Unchecked_Convert_To (Pref_Type, | |
6540 | Duplicate_Subexpr (Pref)), | |
6541 | Selector_Name => New_Occurrence_Of (Real_Discr, Loc)); | |
6542 | ||
6543 | -- Manually analyze and resolve this selected component. We really | |
6544 | -- want it just as it appears above, and do not want the expander | |
feff2f05 | 6545 | -- playing discriminal games etc with this reference. Then we append |
6546 | -- the argument to the list we are gathering. | |
9dfe12ae | 6547 | |
6548 | Set_Etype (Scomp, Etype (Real_Discr)); | |
6549 | Set_Analyzed (Scomp, True); | |
6550 | Append_To (Args, Convert_To (Etype (Formal), Scomp)); | |
6551 | ||
6552 | Next_Formal_With_Extras (Formal); | |
6553 | Next_Discriminant (Discr); | |
6554 | end loop; | |
6555 | ||
6556 | -- Now build and insert the call | |
6557 | ||
6558 | Insert_Action (N, | |
6559 | Make_Raise_Constraint_Error (Loc, | |
6560 | Condition => | |
6561 | Make_Function_Call (Loc, | |
20cf157b | 6562 | Name => New_Occurrence_Of (Discr_Fct, Loc), |
9dfe12ae | 6563 | Parameter_Associations => Args), |
6564 | Reason => CE_Discriminant_Check_Failed)); | |
6565 | end Generate_Discriminant_Check; | |
6566 | ||
5c99c290 | 6567 | --------------------------- |
6568 | -- Generate_Index_Checks -- | |
6569 | --------------------------- | |
9dfe12ae | 6570 | |
6571 | procedure Generate_Index_Checks (N : Node_Id) is | |
05f3e139 | 6572 | |
6573 | function Entity_Of_Prefix return Entity_Id; | |
6574 | -- Returns the entity of the prefix of N (or Empty if not found) | |
6575 | ||
3f42e2a7 | 6576 | ---------------------- |
6577 | -- Entity_Of_Prefix -- | |
6578 | ---------------------- | |
6579 | ||
05f3e139 | 6580 | function Entity_Of_Prefix return Entity_Id is |
e5d38095 | 6581 | P : Node_Id; |
6582 | ||
05f3e139 | 6583 | begin |
e5d38095 | 6584 | P := Prefix (N); |
05f3e139 | 6585 | while not Is_Entity_Name (P) loop |
6586 | if not Nkind_In (P, N_Selected_Component, | |
6587 | N_Indexed_Component) | |
6588 | then | |
6589 | return Empty; | |
6590 | end if; | |
6591 | ||
6592 | P := Prefix (P); | |
6593 | end loop; | |
6594 | ||
6595 | return Entity (P); | |
6596 | end Entity_Of_Prefix; | |
6597 | ||
6598 | -- Local variables | |
6599 | ||
6600 | Loc : constant Source_Ptr := Sloc (N); | |
6601 | A : constant Node_Id := Prefix (N); | |
6602 | A_Ent : constant Entity_Id := Entity_Of_Prefix; | |
6603 | Sub : Node_Id; | |
9dfe12ae | 6604 | |
3f42e2a7 | 6605 | -- Start of processing for Generate_Index_Checks |
6606 | ||
9dfe12ae | 6607 | begin |
05f3e139 | 6608 | -- Ignore call if the prefix is not an array since we have a serious |
6609 | -- error in the sources. Ignore it also if index checks are suppressed | |
6610 | -- for array object or type. | |
0577b0b1 | 6611 | |
05f3e139 | 6612 | if not Is_Array_Type (Etype (A)) |
20cf157b | 6613 | or else (Present (A_Ent) and then Index_Checks_Suppressed (A_Ent)) |
0577b0b1 | 6614 | or else Index_Checks_Suppressed (Etype (A)) |
6615 | then | |
6616 | return; | |
df9fba45 | 6617 | |
6618 | -- The indexed component we are dealing with contains 'Loop_Entry in its | |
6619 | -- prefix. This case arises when analysis has determined that constructs | |
6620 | -- such as | |
6621 | ||
6622 | -- Prefix'Loop_Entry (Expr) | |
6623 | -- Prefix'Loop_Entry (Expr1, Expr2, ... ExprN) | |
6624 | ||
6625 | -- require rewriting for error detection purposes. A side effect of this | |
6626 | -- action is the generation of index checks that mention 'Loop_Entry. | |
6627 | -- Delay the generation of the check until 'Loop_Entry has been properly | |
6628 | -- expanded. This is done in Expand_Loop_Entry_Attributes. | |
6629 | ||
6630 | elsif Nkind (Prefix (N)) = N_Attribute_Reference | |
6631 | and then Attribute_Name (Prefix (N)) = Name_Loop_Entry | |
6632 | then | |
6633 | return; | |
0577b0b1 | 6634 | end if; |
6635 | ||
05f3e139 | 6636 | -- Generate a raise of constraint error with the appropriate reason and |
6637 | -- a condition of the form: | |
6638 | ||
3f42e2a7 | 6639 | -- Base_Type (Sub) not in Array'Range (Subscript) |
05f3e139 | 6640 | |
6641 | -- Note that the reason we generate the conversion to the base type here | |
6642 | -- is that we definitely want the range check to take place, even if it | |
6643 | -- looks like the subtype is OK. Optimization considerations that allow | |
6644 | -- us to omit the check have already been taken into account in the | |
6645 | -- setting of the Do_Range_Check flag earlier on. | |
0577b0b1 | 6646 | |
9dfe12ae | 6647 | Sub := First (Expressions (N)); |
05f3e139 | 6648 | |
6649 | -- Handle string literals | |
6650 | ||
6651 | if Ekind (Etype (A)) = E_String_Literal_Subtype then | |
9dfe12ae | 6652 | if Do_Range_Check (Sub) then |
6653 | Set_Do_Range_Check (Sub, False); | |
6654 | ||
05f3e139 | 6655 | -- For string literals we obtain the bounds of the string from the |
6656 | -- associated subtype. | |
9dfe12ae | 6657 | |
05f3e139 | 6658 | Insert_Action (N, |
094ed68e | 6659 | Make_Raise_Constraint_Error (Loc, |
6660 | Condition => | |
6661 | Make_Not_In (Loc, | |
6662 | Left_Opnd => | |
6663 | Convert_To (Base_Type (Etype (Sub)), | |
6664 | Duplicate_Subexpr_Move_Checks (Sub)), | |
6665 | Right_Opnd => | |
6666 | Make_Attribute_Reference (Loc, | |
83c6c069 | 6667 | Prefix => New_Occurrence_Of (Etype (A), Loc), |
094ed68e | 6668 | Attribute_Name => Name_Range)), |
6669 | Reason => CE_Index_Check_Failed)); | |
05f3e139 | 6670 | end if; |
9dfe12ae | 6671 | |
05f3e139 | 6672 | -- General case |
9dfe12ae | 6673 | |
05f3e139 | 6674 | else |
6675 | declare | |
6676 | A_Idx : Node_Id := Empty; | |
6677 | A_Range : Node_Id; | |
6678 | Ind : Nat; | |
6679 | Num : List_Id; | |
6680 | Range_N : Node_Id; | |
9dfe12ae | 6681 | |
05f3e139 | 6682 | begin |
6683 | A_Idx := First_Index (Etype (A)); | |
6684 | Ind := 1; | |
6685 | while Present (Sub) loop | |
6686 | if Do_Range_Check (Sub) then | |
6687 | Set_Do_Range_Check (Sub, False); | |
9dfe12ae | 6688 | |
05f3e139 | 6689 | -- Force evaluation except for the case of a simple name of |
f9906591 | 6690 | -- a nonvolatile entity. |
9dfe12ae | 6691 | |
05f3e139 | 6692 | if not Is_Entity_Name (Sub) |
6693 | or else Treat_As_Volatile (Entity (Sub)) | |
6694 | then | |
6695 | Force_Evaluation (Sub); | |
6696 | end if; | |
9dfe12ae | 6697 | |
05f3e139 | 6698 | if Nkind (A_Idx) = N_Range then |
6699 | A_Range := A_Idx; | |
6700 | ||
6701 | elsif Nkind (A_Idx) = N_Identifier | |
6702 | or else Nkind (A_Idx) = N_Expanded_Name | |
6703 | then | |
6704 | A_Range := Scalar_Range (Entity (A_Idx)); | |
6705 | ||
6706 | else pragma Assert (Nkind (A_Idx) = N_Subtype_Indication); | |
6707 | A_Range := Range_Expression (Constraint (A_Idx)); | |
6708 | end if; | |
6709 | ||
6710 | -- For array objects with constant bounds we can generate | |
6711 | -- the index check using the bounds of the type of the index | |
6712 | ||
6713 | if Present (A_Ent) | |
6714 | and then Ekind (A_Ent) = E_Variable | |
6715 | and then Is_Constant_Bound (Low_Bound (A_Range)) | |
6716 | and then Is_Constant_Bound (High_Bound (A_Range)) | |
6717 | then | |
6718 | Range_N := | |
6719 | Make_Attribute_Reference (Loc, | |
3f42e2a7 | 6720 | Prefix => |
83c6c069 | 6721 | New_Occurrence_Of (Etype (A_Idx), Loc), |
05f3e139 | 6722 | Attribute_Name => Name_Range); |
6723 | ||
6724 | -- For arrays with non-constant bounds we cannot generate | |
6725 | -- the index check using the bounds of the type of the index | |
6726 | -- since it may reference discriminants of some enclosing | |
6727 | -- type. We obtain the bounds directly from the prefix | |
6728 | -- object. | |
6729 | ||
6730 | else | |
6731 | if Ind = 1 then | |
6732 | Num := No_List; | |
6733 | else | |
6734 | Num := New_List (Make_Integer_Literal (Loc, Ind)); | |
6735 | end if; | |
6736 | ||
6737 | Range_N := | |
6738 | Make_Attribute_Reference (Loc, | |
6739 | Prefix => | |
6740 | Duplicate_Subexpr_Move_Checks (A, Name_Req => True), | |
6741 | Attribute_Name => Name_Range, | |
6742 | Expressions => Num); | |
6743 | end if; | |
6744 | ||
6745 | Insert_Action (N, | |
094ed68e | 6746 | Make_Raise_Constraint_Error (Loc, |
6747 | Condition => | |
6748 | Make_Not_In (Loc, | |
6749 | Left_Opnd => | |
6750 | Convert_To (Base_Type (Etype (Sub)), | |
6751 | Duplicate_Subexpr_Move_Checks (Sub)), | |
6752 | Right_Opnd => Range_N), | |
6753 | Reason => CE_Index_Check_Failed)); | |
05f3e139 | 6754 | end if; |
6755 | ||
6756 | A_Idx := Next_Index (A_Idx); | |
6757 | Ind := Ind + 1; | |
6758 | Next (Sub); | |
6759 | end loop; | |
6760 | end; | |
6761 | end if; | |
9dfe12ae | 6762 | end Generate_Index_Checks; |
6763 | ||
6764 | -------------------------- | |
6765 | -- Generate_Range_Check -- | |
6766 | -------------------------- | |
6767 | ||
6768 | procedure Generate_Range_Check | |
6769 | (N : Node_Id; | |
6770 | Target_Type : Entity_Id; | |
6771 | Reason : RT_Exception_Code) | |
6772 | is | |
6773 | Loc : constant Source_Ptr := Sloc (N); | |
6774 | Source_Type : constant Entity_Id := Etype (N); | |
6775 | Source_Base_Type : constant Entity_Id := Base_Type (Source_Type); | |
6776 | Target_Base_Type : constant Entity_Id := Base_Type (Target_Type); | |
6777 | ||
1f5d83cf | 6778 | procedure Convert_And_Check_Range; |
6779 | -- Convert the conversion operand to the target base type and save in | |
6780 | -- a temporary. Then check the converted value against the range of the | |
6781 | -- target subtype. | |
6782 | ||
124f1911 | 6783 | ----------------------------- |
6784 | -- Convert_And_Check_Range -- | |
6785 | ----------------------------- | |
1f5d83cf | 6786 | |
124f1911 | 6787 | procedure Convert_And_Check_Range is |
cdfda0e3 | 6788 | Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
6789 | Conv_Node : Node_Id; | |
1f5d83cf | 6790 | |
124f1911 | 6791 | begin |
cdfda0e3 | 6792 | -- For enumeration types with non-standard representation this is a |
6793 | -- direct conversion from the enumeration type to the target integer | |
6794 | -- type, which is treated by the back end as a normal integer type | |
6795 | -- conversion, treating the enumeration type as an integer, which is | |
6796 | -- exactly what we want. We set Conversion_OK to make sure that the | |
6797 | -- analyzer does not complain about what otherwise might be an | |
6798 | -- illegal conversion. | |
6799 | ||
6800 | if Is_Enumeration_Type (Source_Base_Type) | |
6801 | and then Present (Enum_Pos_To_Rep (Source_Base_Type)) | |
6802 | and then Is_Integer_Type (Target_Base_Type) | |
6803 | then | |
6804 | Conv_Node := | |
96cb18c0 | 6805 | OK_Convert_To |
6806 | (Typ => Target_Base_Type, | |
6807 | Expr => Duplicate_Subexpr (N)); | |
cdfda0e3 | 6808 | |
6809 | -- Common case | |
6810 | ||
6811 | else | |
6812 | Conv_Node := | |
6813 | Make_Type_Conversion (Loc, | |
6814 | Subtype_Mark => New_Occurrence_Of (Target_Base_Type, Loc), | |
6815 | Expression => Duplicate_Subexpr (N)); | |
6816 | end if; | |
6817 | ||
124f1911 | 6818 | -- We make a temporary to hold the value of the converted value |
6819 | -- (converted to the base type), and then do the test against this | |
6820 | -- temporary. The conversion itself is replaced by an occurrence of | |
6821 | -- Tnn and followed by the explicit range check. Note that checks | |
6822 | -- are suppressed for this code, since we don't want a recursive | |
1f5d83cf | 6823 | -- range check popping up. |
6824 | ||
124f1911 | 6825 | -- Tnn : constant Target_Base_Type := Target_Base_Type (N); |
6826 | -- [constraint_error when Tnn not in Target_Type] | |
6827 | ||
1f5d83cf | 6828 | Insert_Actions (N, New_List ( |
6829 | Make_Object_Declaration (Loc, | |
6830 | Defining_Identifier => Tnn, | |
6831 | Object_Definition => New_Occurrence_Of (Target_Base_Type, Loc), | |
6832 | Constant_Present => True, | |
cdfda0e3 | 6833 | Expression => Conv_Node), |
1f5d83cf | 6834 | |
6835 | Make_Raise_Constraint_Error (Loc, | |
6836 | Condition => | |
6837 | Make_Not_In (Loc, | |
6838 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
6839 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
6840 | Reason => Reason)), | |
6841 | Suppress => All_Checks); | |
6842 | ||
6843 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
6844 | ||
6845 | -- Set the type of N, because the declaration for Tnn might not | |
6846 | -- be analyzed yet, as is the case if N appears within a record | |
6847 | -- declaration, as a discriminant constraint or expression. | |
6848 | ||
6849 | Set_Etype (N, Target_Base_Type); | |
6850 | end Convert_And_Check_Range; | |
6851 | ||
6852 | -- Start of processing for Generate_Range_Check | |
6853 | ||
9dfe12ae | 6854 | begin |
feff2f05 | 6855 | -- First special case, if the source type is already within the range |
6856 | -- of the target type, then no check is needed (probably we should have | |
6857 | -- stopped Do_Range_Check from being set in the first place, but better | |
cda40848 | 6858 | -- late than never in preventing junk code and junk flag settings. |
9dfe12ae | 6859 | |
7a1dabb3 | 6860 | if In_Subrange_Of (Source_Type, Target_Type) |
b40670e1 | 6861 | |
6862 | -- We do NOT apply this if the source node is a literal, since in this | |
6863 | -- case the literal has already been labeled as having the subtype of | |
6864 | -- the target. | |
6865 | ||
9dfe12ae | 6866 | and then not |
b40670e1 | 6867 | (Nkind_In (N, N_Integer_Literal, N_Real_Literal, N_Character_Literal) |
9dfe12ae | 6868 | or else |
b40670e1 | 6869 | (Is_Entity_Name (N) |
6870 | and then Ekind (Entity (N)) = E_Enumeration_Literal)) | |
9dfe12ae | 6871 | then |
cda40848 | 6872 | Set_Do_Range_Check (N, False); |
9dfe12ae | 6873 | return; |
6874 | end if; | |
6875 | ||
cda40848 | 6876 | -- Here a check is needed. If the expander is not active, or if we are |
6877 | -- in GNATProve mode, then simply set the Do_Range_Check flag and we | |
6878 | -- are done. In both these cases, we just want to see the range check | |
6879 | -- flag set, we do not want to generate the explicit range check code. | |
6880 | ||
6881 | if GNATprove_Mode or else not Expander_Active then | |
6882 | Set_Do_Range_Check (N, True); | |
6883 | return; | |
6884 | end if; | |
6885 | ||
6886 | -- Here we will generate an explicit range check, so we don't want to | |
6887 | -- set the Do_Range check flag, since the range check is taken care of | |
6888 | -- by the code we will generate. | |
6889 | ||
6890 | Set_Do_Range_Check (N, False); | |
6891 | ||
6892 | -- Force evaluation of the node, so that it does not get evaluated twice | |
6893 | -- (once for the check, once for the actual reference). Such a double | |
6894 | -- evaluation is always a potential source of inefficiency, and is | |
6895 | -- functionally incorrect in the volatile case. | |
9dfe12ae | 6896 | |
f47b9548 | 6897 | -- We skip the evaluation of attribute references because, after these |
6898 | -- runtime checks are generated, the expander may need to rewrite this | |
6899 | -- node (for example, see Attribute_Max_Size_In_Storage_Elements in | |
6900 | -- Expand_N_Attribute_Reference). | |
6901 | ||
6902 | if Nkind (N) /= N_Attribute_Reference | |
6903 | and then (not Is_Entity_Name (N) | |
ca09bfdb | 6904 | or else Treat_As_Volatile (Entity (N))) |
f47b9548 | 6905 | then |
6906 | Force_Evaluation (N, Mode => Strict); | |
9dfe12ae | 6907 | end if; |
6908 | ||
feff2f05 | 6909 | -- The easiest case is when Source_Base_Type and Target_Base_Type are |
6910 | -- the same since in this case we can simply do a direct check of the | |
6911 | -- value of N against the bounds of Target_Type. | |
9dfe12ae | 6912 | |
6913 | -- [constraint_error when N not in Target_Type] | |
6914 | ||
6915 | -- Note: this is by far the most common case, for example all cases of | |
6916 | -- checks on the RHS of assignments are in this category, but not all | |
6917 | -- cases are like this. Notably conversions can involve two types. | |
6918 | ||
6919 | if Source_Base_Type = Target_Base_Type then | |
99ed4b4c | 6920 | |
6921 | -- Insert the explicit range check. Note that we suppress checks for | |
6922 | -- this code, since we don't want a recursive range check popping up. | |
6923 | ||
9dfe12ae | 6924 | Insert_Action (N, |
6925 | Make_Raise_Constraint_Error (Loc, | |
6926 | Condition => | |
6927 | Make_Not_In (Loc, | |
6928 | Left_Opnd => Duplicate_Subexpr (N), | |
6929 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
99ed4b4c | 6930 | Reason => Reason), |
6931 | Suppress => All_Checks); | |
9dfe12ae | 6932 | |
6933 | -- Next test for the case where the target type is within the bounds | |
6934 | -- of the base type of the source type, since in this case we can | |
6935 | -- simply convert these bounds to the base type of T to do the test. | |
6936 | ||
6937 | -- [constraint_error when N not in | |
6938 | -- Source_Base_Type (Target_Type'First) | |
6939 | -- .. | |
6940 | -- Source_Base_Type(Target_Type'Last))] | |
6941 | ||
f2a06be9 | 6942 | -- The conversions will always work and need no check |
9dfe12ae | 6943 | |
a9b57347 | 6944 | -- Unchecked_Convert_To is used instead of Convert_To to handle the case |
6945 | -- of converting from an enumeration value to an integer type, such as | |
6946 | -- occurs for the case of generating a range check on Enum'Val(Exp) | |
6947 | -- (which used to be handled by gigi). This is OK, since the conversion | |
6948 | -- itself does not require a check. | |
6949 | ||
7a1dabb3 | 6950 | elsif In_Subrange_Of (Target_Type, Source_Base_Type) then |
99ed4b4c | 6951 | |
6952 | -- Insert the explicit range check. Note that we suppress checks for | |
6953 | -- this code, since we don't want a recursive range check popping up. | |
6954 | ||
1f5d83cf | 6955 | if Is_Discrete_Type (Source_Base_Type) |
6956 | and then | |
6957 | Is_Discrete_Type (Target_Base_Type) | |
6958 | then | |
6959 | Insert_Action (N, | |
6960 | Make_Raise_Constraint_Error (Loc, | |
6961 | Condition => | |
6962 | Make_Not_In (Loc, | |
6963 | Left_Opnd => Duplicate_Subexpr (N), | |
6964 | ||
6965 | Right_Opnd => | |
6966 | Make_Range (Loc, | |
6967 | Low_Bound => | |
6968 | Unchecked_Convert_To (Source_Base_Type, | |
6969 | Make_Attribute_Reference (Loc, | |
6970 | Prefix => | |
6971 | New_Occurrence_Of (Target_Type, Loc), | |
6972 | Attribute_Name => Name_First)), | |
6973 | ||
6974 | High_Bound => | |
6975 | Unchecked_Convert_To (Source_Base_Type, | |
6976 | Make_Attribute_Reference (Loc, | |
6977 | Prefix => | |
6978 | New_Occurrence_Of (Target_Type, Loc), | |
6979 | Attribute_Name => Name_Last)))), | |
6980 | Reason => Reason), | |
6981 | Suppress => All_Checks); | |
9dfe12ae | 6982 | |
1f5d83cf | 6983 | -- For conversions involving at least one type that is not discrete, |
6984 | -- first convert to target type and then generate the range check. | |
6985 | -- This avoids problems with values that are close to a bound of the | |
6986 | -- target type that would fail a range check when done in a larger | |
6987 | -- source type before converting but would pass if converted with | |
6988 | -- rounding and then checked (such as in float-to-float conversions). | |
6989 | ||
6990 | else | |
6991 | Convert_And_Check_Range; | |
6992 | end if; | |
9dfe12ae | 6993 | |
feff2f05 | 6994 | -- Note that at this stage we now that the Target_Base_Type is not in |
6995 | -- the range of the Source_Base_Type (since even the Target_Type itself | |
6996 | -- is not in this range). It could still be the case that Source_Type is | |
6997 | -- in range of the target base type since we have not checked that case. | |
9dfe12ae | 6998 | |
feff2f05 | 6999 | -- If that is the case, we can freely convert the source to the target, |
7000 | -- and then test the target result against the bounds. | |
9dfe12ae | 7001 | |
7a1dabb3 | 7002 | elsif In_Subrange_Of (Source_Type, Target_Base_Type) then |
1f5d83cf | 7003 | Convert_And_Check_Range; |
9dfe12ae | 7004 | |
7005 | -- At this stage, we know that we have two scalar types, which are | |
7006 | -- directly convertible, and where neither scalar type has a base | |
7007 | -- range that is in the range of the other scalar type. | |
7008 | ||
7009 | -- The only way this can happen is with a signed and unsigned type. | |
7010 | -- So test for these two cases: | |
7011 | ||
7012 | else | |
7013 | -- Case of the source is unsigned and the target is signed | |
7014 | ||
7015 | if Is_Unsigned_Type (Source_Base_Type) | |
7016 | and then not Is_Unsigned_Type (Target_Base_Type) | |
7017 | then | |
7018 | -- If the source is unsigned and the target is signed, then we | |
7019 | -- know that the source is not shorter than the target (otherwise | |
7020 | -- the source base type would be in the target base type range). | |
7021 | ||
feff2f05 | 7022 | -- In other words, the unsigned type is either the same size as |
7023 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 7024 | |
7025 | pragma Assert | |
7026 | (Esize (Source_Base_Type) >= Esize (Target_Base_Type)); | |
7027 | ||
7028 | -- We only need to check the low bound if the low bound of the | |
7029 | -- target type is non-negative. If the low bound of the target | |
7030 | -- type is negative, then we know that we will fit fine. | |
7031 | ||
7032 | -- If the high bound of the target type is negative, then we | |
7033 | -- know we have a constraint error, since we can't possibly | |
7034 | -- have a negative source. | |
7035 | ||
7036 | -- With these two checks out of the way, we can do the check | |
7037 | -- using the source type safely | |
7038 | ||
39a0c1d3 | 7039 | -- This is definitely the most annoying case. |
9dfe12ae | 7040 | |
7041 | -- [constraint_error | |
7042 | -- when (Target_Type'First >= 0 | |
7043 | -- and then | |
7044 | -- N < Source_Base_Type (Target_Type'First)) | |
7045 | -- or else Target_Type'Last < 0 | |
7046 | -- or else N > Source_Base_Type (Target_Type'Last)]; | |
7047 | ||
7048 | -- We turn off all checks since we know that the conversions | |
7049 | -- will work fine, given the guards for negative values. | |
7050 | ||
7051 | Insert_Action (N, | |
7052 | Make_Raise_Constraint_Error (Loc, | |
7053 | Condition => | |
7054 | Make_Or_Else (Loc, | |
7055 | Make_Or_Else (Loc, | |
7056 | Left_Opnd => | |
7057 | Make_And_Then (Loc, | |
7058 | Left_Opnd => Make_Op_Ge (Loc, | |
7059 | Left_Opnd => | |
7060 | Make_Attribute_Reference (Loc, | |
7061 | Prefix => | |
7062 | New_Occurrence_Of (Target_Type, Loc), | |
7063 | Attribute_Name => Name_First), | |
7064 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
7065 | ||
7066 | Right_Opnd => | |
7067 | Make_Op_Lt (Loc, | |
7068 | Left_Opnd => Duplicate_Subexpr (N), | |
7069 | Right_Opnd => | |
7070 | Convert_To (Source_Base_Type, | |
7071 | Make_Attribute_Reference (Loc, | |
7072 | Prefix => | |
7073 | New_Occurrence_Of (Target_Type, Loc), | |
7074 | Attribute_Name => Name_First)))), | |
7075 | ||
7076 | Right_Opnd => | |
7077 | Make_Op_Lt (Loc, | |
7078 | Left_Opnd => | |
7079 | Make_Attribute_Reference (Loc, | |
7080 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
7081 | Attribute_Name => Name_Last), | |
7082 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0))), | |
7083 | ||
7084 | Right_Opnd => | |
7085 | Make_Op_Gt (Loc, | |
7086 | Left_Opnd => Duplicate_Subexpr (N), | |
7087 | Right_Opnd => | |
7088 | Convert_To (Source_Base_Type, | |
7089 | Make_Attribute_Reference (Loc, | |
7090 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
7091 | Attribute_Name => Name_Last)))), | |
7092 | ||
7093 | Reason => Reason), | |
7094 | Suppress => All_Checks); | |
7095 | ||
7096 | -- Only remaining possibility is that the source is signed and | |
fc75802a | 7097 | -- the target is unsigned. |
9dfe12ae | 7098 | |
7099 | else | |
7100 | pragma Assert (not Is_Unsigned_Type (Source_Base_Type) | |
20cf157b | 7101 | and then Is_Unsigned_Type (Target_Base_Type)); |
9dfe12ae | 7102 | |
feff2f05 | 7103 | -- If the source is signed and the target is unsigned, then we |
7104 | -- know that the target is not shorter than the source (otherwise | |
7105 | -- the target base type would be in the source base type range). | |
9dfe12ae | 7106 | |
feff2f05 | 7107 | -- In other words, the unsigned type is either the same size as |
7108 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 7109 | |
feff2f05 | 7110 | -- Clearly we have an error if the source value is negative since |
7111 | -- no unsigned type can have negative values. If the source type | |
7112 | -- is non-negative, then the check can be done using the target | |
7113 | -- type. | |
9dfe12ae | 7114 | |
7115 | -- Tnn : constant Target_Base_Type (N) := Target_Type; | |
7116 | ||
7117 | -- [constraint_error | |
7118 | -- when N < 0 or else Tnn not in Target_Type]; | |
7119 | ||
feff2f05 | 7120 | -- We turn off all checks for the conversion of N to the target |
7121 | -- base type, since we generate the explicit check to ensure that | |
7122 | -- the value is non-negative | |
9dfe12ae | 7123 | |
7124 | declare | |
46eb6933 | 7125 | Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
9dfe12ae | 7126 | |
7127 | begin | |
7128 | Insert_Actions (N, New_List ( | |
7129 | Make_Object_Declaration (Loc, | |
7130 | Defining_Identifier => Tnn, | |
7131 | Object_Definition => | |
7132 | New_Occurrence_Of (Target_Base_Type, Loc), | |
7133 | Constant_Present => True, | |
7134 | Expression => | |
a9b57347 | 7135 | Make_Unchecked_Type_Conversion (Loc, |
9dfe12ae | 7136 | Subtype_Mark => |
7137 | New_Occurrence_Of (Target_Base_Type, Loc), | |
7138 | Expression => Duplicate_Subexpr (N))), | |
7139 | ||
7140 | Make_Raise_Constraint_Error (Loc, | |
7141 | Condition => | |
7142 | Make_Or_Else (Loc, | |
7143 | Left_Opnd => | |
7144 | Make_Op_Lt (Loc, | |
7145 | Left_Opnd => Duplicate_Subexpr (N), | |
7146 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
7147 | ||
7148 | Right_Opnd => | |
7149 | Make_Not_In (Loc, | |
7150 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
7151 | Right_Opnd => | |
7152 | New_Occurrence_Of (Target_Type, Loc))), | |
7153 | ||
20cf157b | 7154 | Reason => Reason)), |
9dfe12ae | 7155 | Suppress => All_Checks); |
7156 | ||
feff2f05 | 7157 | -- Set the Etype explicitly, because Insert_Actions may have |
7158 | -- placed the declaration in the freeze list for an enclosing | |
7159 | -- construct, and thus it is not analyzed yet. | |
9dfe12ae | 7160 | |
7161 | Set_Etype (Tnn, Target_Base_Type); | |
7162 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
7163 | end; | |
7164 | end if; | |
7165 | end if; | |
7166 | end Generate_Range_Check; | |
7167 | ||
2af58f67 | 7168 | ------------------ |
7169 | -- Get_Check_Id -- | |
7170 | ------------------ | |
7171 | ||
7172 | function Get_Check_Id (N : Name_Id) return Check_Id is | |
7173 | begin | |
7174 | -- For standard check name, we can do a direct computation | |
7175 | ||
7176 | if N in First_Check_Name .. Last_Check_Name then | |
7177 | return Check_Id (N - (First_Check_Name - 1)); | |
7178 | ||
7179 | -- For non-standard names added by pragma Check_Name, search table | |
7180 | ||
7181 | else | |
7182 | for J in All_Checks + 1 .. Check_Names.Last loop | |
7183 | if Check_Names.Table (J) = N then | |
7184 | return J; | |
7185 | end if; | |
7186 | end loop; | |
7187 | end if; | |
7188 | ||
7189 | -- No matching name found | |
7190 | ||
7191 | return No_Check_Id; | |
7192 | end Get_Check_Id; | |
7193 | ||
ee6ba406 | 7194 | --------------------- |
7195 | -- Get_Discriminal -- | |
7196 | --------------------- | |
7197 | ||
7198 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is | |
7199 | Loc : constant Source_Ptr := Sloc (E); | |
7200 | D : Entity_Id; | |
7201 | Sc : Entity_Id; | |
7202 | ||
7203 | begin | |
0577b0b1 | 7204 | -- The bound can be a bona fide parameter of a protected operation, |
7205 | -- rather than a prival encoded as an in-parameter. | |
7206 | ||
7207 | if No (Discriminal_Link (Entity (Bound))) then | |
7208 | return Bound; | |
7209 | end if; | |
7210 | ||
2af58f67 | 7211 | -- Climb the scope stack looking for an enclosing protected type. If |
7212 | -- we run out of scopes, return the bound itself. | |
7213 | ||
7214 | Sc := Scope (E); | |
7215 | while Present (Sc) loop | |
7216 | if Sc = Standard_Standard then | |
7217 | return Bound; | |
2af58f67 | 7218 | elsif Ekind (Sc) = E_Protected_Type then |
7219 | exit; | |
7220 | end if; | |
7221 | ||
7222 | Sc := Scope (Sc); | |
7223 | end loop; | |
7224 | ||
ee6ba406 | 7225 | D := First_Discriminant (Sc); |
2af58f67 | 7226 | while Present (D) loop |
7227 | if Chars (D) = Chars (Bound) then | |
7228 | return New_Occurrence_Of (Discriminal (D), Loc); | |
7229 | end if; | |
ee6ba406 | 7230 | |
ee6ba406 | 7231 | Next_Discriminant (D); |
7232 | end loop; | |
7233 | ||
2af58f67 | 7234 | return Bound; |
ee6ba406 | 7235 | end Get_Discriminal; |
7236 | ||
2af58f67 | 7237 | ---------------------- |
7238 | -- Get_Range_Checks -- | |
7239 | ---------------------- | |
7240 | ||
7241 | function Get_Range_Checks | |
7242 | (Ck_Node : Node_Id; | |
7243 | Target_Typ : Entity_Id; | |
7244 | Source_Typ : Entity_Id := Empty; | |
7245 | Warn_Node : Node_Id := Empty) return Check_Result | |
7246 | is | |
7247 | begin | |
20cf157b | 7248 | return |
7249 | Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Warn_Node); | |
2af58f67 | 7250 | end Get_Range_Checks; |
7251 | ||
ee6ba406 | 7252 | ------------------ |
7253 | -- Guard_Access -- | |
7254 | ------------------ | |
7255 | ||
7256 | function Guard_Access | |
7257 | (Cond : Node_Id; | |
7258 | Loc : Source_Ptr; | |
314a23b6 | 7259 | Ck_Node : Node_Id) return Node_Id |
ee6ba406 | 7260 | is |
7261 | begin | |
7262 | if Nkind (Cond) = N_Or_Else then | |
7263 | Set_Paren_Count (Cond, 1); | |
7264 | end if; | |
7265 | ||
7266 | if Nkind (Ck_Node) = N_Allocator then | |
7267 | return Cond; | |
20cf157b | 7268 | |
ee6ba406 | 7269 | else |
7270 | return | |
7271 | Make_And_Then (Loc, | |
7272 | Left_Opnd => | |
7273 | Make_Op_Ne (Loc, | |
9dfe12ae | 7274 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), |
ee6ba406 | 7275 | Right_Opnd => Make_Null (Loc)), |
7276 | Right_Opnd => Cond); | |
7277 | end if; | |
7278 | end Guard_Access; | |
7279 | ||
7280 | ----------------------------- | |
7281 | -- Index_Checks_Suppressed -- | |
7282 | ----------------------------- | |
7283 | ||
7284 | function Index_Checks_Suppressed (E : Entity_Id) return Boolean is | |
7285 | begin | |
9dfe12ae | 7286 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
7287 | return Is_Check_Suppressed (E, Index_Check); | |
7288 | else | |
fafc6b97 | 7289 | return Scope_Suppress.Suppress (Index_Check); |
9dfe12ae | 7290 | end if; |
ee6ba406 | 7291 | end Index_Checks_Suppressed; |
7292 | ||
7293 | ---------------- | |
7294 | -- Initialize -- | |
7295 | ---------------- | |
7296 | ||
7297 | procedure Initialize is | |
7298 | begin | |
7299 | for J in Determine_Range_Cache_N'Range loop | |
7300 | Determine_Range_Cache_N (J) := Empty; | |
7301 | end loop; | |
2af58f67 | 7302 | |
7303 | Check_Names.Init; | |
7304 | ||
7305 | for J in Int range 1 .. All_Checks loop | |
7306 | Check_Names.Append (Name_Id (Int (First_Check_Name) + J - 1)); | |
7307 | end loop; | |
ee6ba406 | 7308 | end Initialize; |
7309 | ||
7310 | ------------------------- | |
7311 | -- Insert_Range_Checks -- | |
7312 | ------------------------- | |
7313 | ||
7314 | procedure Insert_Range_Checks | |
7315 | (Checks : Check_Result; | |
7316 | Node : Node_Id; | |
7317 | Suppress_Typ : Entity_Id; | |
7318 | Static_Sloc : Source_Ptr := No_Location; | |
7319 | Flag_Node : Node_Id := Empty; | |
7320 | Do_Before : Boolean := False) | |
7321 | is | |
2b4f2458 | 7322 | Checks_On : constant Boolean := |
7323 | not Index_Checks_Suppressed (Suppress_Typ) | |
7324 | or else | |
7325 | not Range_Checks_Suppressed (Suppress_Typ); | |
7326 | ||
7327 | Check_Node : Node_Id; | |
ee6ba406 | 7328 | Internal_Flag_Node : Node_Id := Flag_Node; |
7329 | Internal_Static_Sloc : Source_Ptr := Static_Sloc; | |
7330 | ||
ee6ba406 | 7331 | begin |
feff2f05 | 7332 | -- For now we just return if Checks_On is false, however this should be |
7333 | -- enhanced to check for an always True value in the condition and to | |
7334 | -- generate a compilation warning??? | |
ee6ba406 | 7335 | |
ac9184ed | 7336 | if not Expander_Active or not Checks_On then |
ee6ba406 | 7337 | return; |
7338 | end if; | |
7339 | ||
7340 | if Static_Sloc = No_Location then | |
7341 | Internal_Static_Sloc := Sloc (Node); | |
7342 | end if; | |
7343 | ||
7344 | if No (Flag_Node) then | |
7345 | Internal_Flag_Node := Node; | |
7346 | end if; | |
7347 | ||
7348 | for J in 1 .. 2 loop | |
7349 | exit when No (Checks (J)); | |
7350 | ||
7351 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
7352 | and then Present (Condition (Checks (J))) | |
7353 | then | |
7354 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
7355 | Check_Node := Checks (J); | |
7356 | Mark_Rewrite_Insertion (Check_Node); | |
7357 | ||
7358 | if Do_Before then | |
7359 | Insert_Before_And_Analyze (Node, Check_Node); | |
7360 | else | |
7361 | Insert_After_And_Analyze (Node, Check_Node); | |
7362 | end if; | |
7363 | ||
7364 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
7365 | end if; | |
7366 | ||
7367 | else | |
7368 | Check_Node := | |
f15731c4 | 7369 | Make_Raise_Constraint_Error (Internal_Static_Sloc, |
7370 | Reason => CE_Range_Check_Failed); | |
ee6ba406 | 7371 | Mark_Rewrite_Insertion (Check_Node); |
7372 | ||
7373 | if Do_Before then | |
7374 | Insert_Before_And_Analyze (Node, Check_Node); | |
7375 | else | |
7376 | Insert_After_And_Analyze (Node, Check_Node); | |
7377 | end if; | |
7378 | end if; | |
7379 | end loop; | |
7380 | end Insert_Range_Checks; | |
7381 | ||
7382 | ------------------------ | |
7383 | -- Insert_Valid_Check -- | |
7384 | ------------------------ | |
7385 | ||
aaec8d13 | 7386 | procedure Insert_Valid_Check |
7387 | (Expr : Node_Id; | |
7388 | Related_Id : Entity_Id := Empty; | |
7389 | Is_Low_Bound : Boolean := False; | |
7390 | Is_High_Bound : Boolean := False) | |
7391 | is | |
ee6ba406 | 7392 | Loc : constant Source_Ptr := Sloc (Expr); |
70580828 | 7393 | Typ : constant Entity_Id := Etype (Expr); |
8b718dab | 7394 | Exp : Node_Id; |
ee6ba406 | 7395 | |
7396 | begin | |
aaec8d13 | 7397 | -- Do not insert if checks off, or if not checking validity or if |
7398 | -- expression is known to be valid. | |
ee6ba406 | 7399 | |
0577b0b1 | 7400 | if not Validity_Checks_On |
7401 | or else Range_Or_Validity_Checks_Suppressed (Expr) | |
06ad5813 | 7402 | or else Expr_Known_Valid (Expr) |
ee6ba406 | 7403 | then |
8b718dab | 7404 | return; |
ee6ba406 | 7405 | |
42c57d55 | 7406 | -- Do not insert checks within a predicate function. This will arise |
7407 | -- if the current unit and the predicate function are being compiled | |
7408 | -- with validity checks enabled. | |
70580828 | 7409 | |
89e864b9 | 7410 | elsif Present (Predicate_Function (Typ)) |
70580828 | 7411 | and then Current_Scope = Predicate_Function (Typ) |
7412 | then | |
7413 | return; | |
70580828 | 7414 | |
310c1cde | 7415 | -- If the expression is a packed component of a modular type of the |
7416 | -- right size, the data is always valid. | |
7417 | ||
89e864b9 | 7418 | elsif Nkind (Expr) = N_Selected_Component |
310c1cde | 7419 | and then Present (Component_Clause (Entity (Selector_Name (Expr)))) |
7420 | and then Is_Modular_Integer_Type (Typ) | |
7421 | and then Modulus (Typ) = 2 ** Esize (Entity (Selector_Name (Expr))) | |
7422 | then | |
7423 | return; | |
89e864b9 | 7424 | |
7425 | -- Do not generate a validity check when inside a generic unit as this | |
7426 | -- is an expansion activity. | |
7427 | ||
7428 | elsif Inside_A_Generic then | |
7429 | return; | |
310c1cde | 7430 | end if; |
7431 | ||
866fa2d0 | 7432 | -- Entities declared in Lock_free protected types must be treated |
7433 | -- as volatile, and we must inhibit validity checks to prevent | |
7434 | -- improper constant folding. | |
7435 | ||
7436 | if Is_Entity_Name (Expr) | |
7437 | and then Is_Subprogram (Scope (Entity (Expr))) | |
7438 | and then Present (Protected_Subprogram (Scope (Entity (Expr)))) | |
7439 | and then Uses_Lock_Free | |
7440 | (Scope (Protected_Subprogram (Scope (Entity (Expr))))) | |
7441 | then | |
7442 | return; | |
7443 | end if; | |
7444 | ||
8b718dab | 7445 | -- If we have a checked conversion, then validity check applies to |
7446 | -- the expression inside the conversion, not the result, since if | |
7447 | -- the expression inside is valid, then so is the conversion result. | |
ee6ba406 | 7448 | |
8b718dab | 7449 | Exp := Expr; |
7450 | while Nkind (Exp) = N_Type_Conversion loop | |
7451 | Exp := Expression (Exp); | |
7452 | end loop; | |
7453 | ||
fdb8488b | 7454 | -- Do not generate a check for a variable which already validates the |
7455 | -- value of an assignable object. | |
7456 | ||
7457 | if Is_Validation_Variable_Reference (Exp) then | |
7458 | return; | |
7459 | end if; | |
7460 | ||
0577b0b1 | 7461 | declare |
49adf385 | 7462 | CE : Node_Id; |
49adf385 | 7463 | PV : Node_Id; |
7464 | Var_Id : Entity_Id; | |
05fcfafb | 7465 | |
0577b0b1 | 7466 | begin |
fdb8488b | 7467 | -- If the expression denotes an assignable object, capture its value |
7468 | -- in a variable and replace the original expression by the variable. | |
7469 | -- This approach has several effects: | |
06ad5813 | 7470 | |
fdb8488b | 7471 | -- 1) The evaluation of the object results in only one read in the |
7472 | -- case where the object is atomic or volatile. | |
fa771c05 | 7473 | |
49adf385 | 7474 | -- Var ... := Object; -- read |
fa771c05 | 7475 | |
fdb8488b | 7476 | -- 2) The captured value is the one verified by attribute 'Valid. |
7477 | -- As a result the object is not evaluated again, which would | |
7478 | -- result in an unwanted read in the case where the object is | |
7479 | -- atomic or volatile. | |
7480 | ||
49adf385 | 7481 | -- if not Var'Valid then -- OK, no read of Object |
fdb8488b | 7482 | |
7483 | -- if not Object'Valid then -- Wrong, extra read of Object | |
7484 | ||
7485 | -- 3) The captured value replaces the original object reference. | |
7486 | -- As a result the object is not evaluated again, in the same | |
7487 | -- vein as 2). | |
7488 | ||
49adf385 | 7489 | -- ... Var ... -- OK, no read of Object |
fdb8488b | 7490 | |
7491 | -- ... Object ... -- Wrong, extra read of Object | |
06ad5813 | 7492 | |
fdb8488b | 7493 | -- 4) The use of a variable to capture the value of the object |
7494 | -- allows the propagation of any changes back to the original | |
7495 | -- object. | |
7496 | ||
7497 | -- procedure Call (Val : in out ...); | |
7498 | ||
49adf385 | 7499 | -- Var : ... := Object; -- read Object |
7500 | -- if not Var'Valid then -- validity check | |
7501 | -- Call (Var); -- modify Var | |
7502 | -- Object := Var; -- update Object | |
fdb8488b | 7503 | |
7504 | if Is_Variable (Exp) then | |
49adf385 | 7505 | Var_Id := Make_Temporary (Loc, 'T', Exp); |
fdb8488b | 7506 | |
4cb8adff | 7507 | -- Because we could be dealing with a transient scope which would |
7508 | -- cause our object declaration to remain unanalyzed we must do | |
7509 | -- some manual decoration. | |
7510 | ||
7511 | Set_Ekind (Var_Id, E_Variable); | |
7512 | Set_Etype (Var_Id, Typ); | |
7513 | ||
fdb8488b | 7514 | Insert_Action (Exp, |
7515 | Make_Object_Declaration (Loc, | |
49adf385 | 7516 | Defining_Identifier => Var_Id, |
fdb8488b | 7517 | Object_Definition => New_Occurrence_Of (Typ, Loc), |
bf5f89dc | 7518 | Expression => New_Copy_Tree (Exp)), |
7519 | Suppress => Validity_Check); | |
7520 | ||
7521 | Set_Validated_Object (Var_Id, New_Copy_Tree (Exp)); | |
49adf385 | 7522 | Rewrite (Exp, New_Occurrence_Of (Var_Id, Loc)); |
7523 | PV := New_Occurrence_Of (Var_Id, Loc); | |
fdb8488b | 7524 | |
02585eb0 | 7525 | -- Copy the Do_Range_Check flag over to the new Exp, so it doesn't |
7526 | -- get lost. Floating point types are handled elsewhere. | |
7527 | ||
7528 | if not Is_Floating_Point_Type (Typ) then | |
7529 | Set_Do_Range_Check (Exp, Do_Range_Check (Original_Node (Exp))); | |
7530 | end if; | |
7531 | ||
fdb8488b | 7532 | -- Otherwise the expression does not denote a variable. Force its |
7533 | -- evaluation by capturing its value in a constant. Generate: | |
7534 | ||
7535 | -- Temp : constant ... := Exp; | |
7536 | ||
7537 | else | |
7538 | Force_Evaluation | |
7539 | (Exp => Exp, | |
7540 | Related_Id => Related_Id, | |
7541 | Is_Low_Bound => Is_Low_Bound, | |
7542 | Is_High_Bound => Is_High_Bound); | |
7543 | ||
7544 | PV := New_Copy_Tree (Exp); | |
7545 | end if; | |
0577b0b1 | 7546 | |
443bdccb | 7547 | -- A rather specialized test. If PV is an analyzed expression which |
7548 | -- is an indexed component of a packed array that has not been | |
7549 | -- properly expanded, turn off its Analyzed flag to make sure it | |
5f46de53 | 7550 | -- gets properly reexpanded. If the prefix is an access value, |
7551 | -- the dereference will be added later. | |
23abd64d | 7552 | |
7553 | -- The reason this arises is that Duplicate_Subexpr_No_Checks did | |
7554 | -- an analyze with the old parent pointer. This may point e.g. to | |
7555 | -- a subprogram call, which deactivates this expansion. | |
7556 | ||
7557 | if Analyzed (PV) | |
7558 | and then Nkind (PV) = N_Indexed_Component | |
5f46de53 | 7559 | and then Is_Array_Type (Etype (Prefix (PV))) |
a88a5773 | 7560 | and then Present (Packed_Array_Impl_Type (Etype (Prefix (PV)))) |
23abd64d | 7561 | then |
7562 | Set_Analyzed (PV, False); | |
7563 | end if; | |
7564 | ||
fa771c05 | 7565 | -- Build the raise CE node to check for validity. We build a type |
7566 | -- qualification for the prefix, since it may not be of the form of | |
7567 | -- a name, and we don't care in this context! | |
23abd64d | 7568 | |
7569 | CE := | |
aaec8d13 | 7570 | Make_Raise_Constraint_Error (Loc, |
7571 | Condition => | |
7572 | Make_Op_Not (Loc, | |
7573 | Right_Opnd => | |
7574 | Make_Attribute_Reference (Loc, | |
7575 | Prefix => PV, | |
7576 | Attribute_Name => Name_Valid)), | |
7577 | Reason => CE_Invalid_Data); | |
23abd64d | 7578 | |
7579 | -- Insert the validity check. Note that we do this with validity | |
7580 | -- checks turned off, to avoid recursion, we do not want validity | |
39a0c1d3 | 7581 | -- checks on the validity checking code itself. |
23abd64d | 7582 | |
7583 | Insert_Action (Expr, CE, Suppress => Validity_Check); | |
0577b0b1 | 7584 | |
6fb3c314 | 7585 | -- If the expression is a reference to an element of a bit-packed |
0577b0b1 | 7586 | -- array, then it is rewritten as a renaming declaration. If the |
7587 | -- expression is an actual in a call, it has not been expanded, | |
7588 | -- waiting for the proper point at which to do it. The same happens | |
7589 | -- with renamings, so that we have to force the expansion now. This | |
7590 | -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb | |
7591 | -- and exp_ch6.adb. | |
7592 | ||
7593 | if Is_Entity_Name (Exp) | |
7594 | and then Nkind (Parent (Entity (Exp))) = | |
20cf157b | 7595 | N_Object_Renaming_Declaration |
0577b0b1 | 7596 | then |
7597 | declare | |
7598 | Old_Exp : constant Node_Id := Name (Parent (Entity (Exp))); | |
7599 | begin | |
7600 | if Nkind (Old_Exp) = N_Indexed_Component | |
7601 | and then Is_Bit_Packed_Array (Etype (Prefix (Old_Exp))) | |
7602 | then | |
7603 | Expand_Packed_Element_Reference (Old_Exp); | |
7604 | end if; | |
7605 | end; | |
7606 | end if; | |
0577b0b1 | 7607 | end; |
ee6ba406 | 7608 | end Insert_Valid_Check; |
7609 | ||
3cce7f32 | 7610 | ------------------------------------- |
7611 | -- Is_Signed_Integer_Arithmetic_Op -- | |
7612 | ------------------------------------- | |
7613 | ||
7614 | function Is_Signed_Integer_Arithmetic_Op (N : Node_Id) return Boolean is | |
7615 | begin | |
7616 | case Nkind (N) is | |
99378362 | 7617 | when N_Op_Abs |
7618 | | N_Op_Add | |
7619 | | N_Op_Divide | |
7620 | | N_Op_Expon | |
7621 | | N_Op_Minus | |
7622 | | N_Op_Mod | |
7623 | | N_Op_Multiply | |
7624 | | N_Op_Plus | |
7625 | | N_Op_Rem | |
7626 | | N_Op_Subtract | |
7627 | => | |
3cce7f32 | 7628 | return Is_Signed_Integer_Type (Etype (N)); |
7629 | ||
99378362 | 7630 | when N_Case_Expression |
7631 | | N_If_Expression | |
7632 | => | |
0326b4d4 | 7633 | return Is_Signed_Integer_Type (Etype (N)); |
7634 | ||
3cce7f32 | 7635 | when others => |
7636 | return False; | |
7637 | end case; | |
7638 | end Is_Signed_Integer_Arithmetic_Op; | |
7639 | ||
fa7497e8 | 7640 | ---------------------------------- |
7641 | -- Install_Null_Excluding_Check -- | |
7642 | ---------------------------------- | |
7643 | ||
7644 | procedure Install_Null_Excluding_Check (N : Node_Id) is | |
9f294c82 | 7645 | Loc : constant Source_Ptr := Sloc (Parent (N)); |
84d0d4a5 | 7646 | Typ : constant Entity_Id := Etype (N); |
7647 | ||
7b31b357 | 7648 | function Safe_To_Capture_In_Parameter_Value return Boolean; |
7649 | -- Determines if it is safe to capture Known_Non_Null status for an | |
7650 | -- the entity referenced by node N. The caller ensures that N is indeed | |
7651 | -- an entity name. It is safe to capture the non-null status for an IN | |
7652 | -- parameter when the reference occurs within a declaration that is sure | |
7653 | -- to be executed as part of the declarative region. | |
7870823d | 7654 | |
84d0d4a5 | 7655 | procedure Mark_Non_Null; |
7870823d | 7656 | -- After installation of check, if the node in question is an entity |
7657 | -- name, then mark this entity as non-null if possible. | |
7658 | ||
7b31b357 | 7659 | function Safe_To_Capture_In_Parameter_Value return Boolean is |
7870823d | 7660 | E : constant Entity_Id := Entity (N); |
7661 | S : constant Entity_Id := Current_Scope; | |
7662 | S_Par : Node_Id; | |
7663 | ||
7664 | begin | |
7b31b357 | 7665 | if Ekind (E) /= E_In_Parameter then |
7666 | return False; | |
7667 | end if; | |
7870823d | 7668 | |
7669 | -- Two initial context checks. We must be inside a subprogram body | |
7670 | -- with declarations and reference must not appear in nested scopes. | |
7671 | ||
7b31b357 | 7672 | if (Ekind (S) /= E_Function and then Ekind (S) /= E_Procedure) |
7870823d | 7673 | or else Scope (E) /= S |
7674 | then | |
7675 | return False; | |
7676 | end if; | |
7677 | ||
7678 | S_Par := Parent (Parent (S)); | |
7679 | ||
7680 | if Nkind (S_Par) /= N_Subprogram_Body | |
7681 | or else No (Declarations (S_Par)) | |
7682 | then | |
7683 | return False; | |
7684 | end if; | |
7685 | ||
7686 | declare | |
7687 | N_Decl : Node_Id; | |
7688 | P : Node_Id; | |
7689 | ||
7690 | begin | |
7691 | -- Retrieve the declaration node of N (if any). Note that N | |
7692 | -- may be a part of a complex initialization expression. | |
7693 | ||
7694 | P := Parent (N); | |
7695 | N_Decl := Empty; | |
7696 | while Present (P) loop | |
7697 | ||
7b31b357 | 7698 | -- If we have a short circuit form, and we are within the right |
7699 | -- hand expression, we return false, since the right hand side | |
7700 | -- is not guaranteed to be elaborated. | |
7701 | ||
7702 | if Nkind (P) in N_Short_Circuit | |
7703 | and then N = Right_Opnd (P) | |
7704 | then | |
7705 | return False; | |
7706 | end if; | |
7707 | ||
92f1631f | 7708 | -- Similarly, if we are in an if expression and not part of the |
7709 | -- condition, then we return False, since neither the THEN or | |
7710 | -- ELSE dependent expressions will always be elaborated. | |
7b31b357 | 7711 | |
92f1631f | 7712 | if Nkind (P) = N_If_Expression |
7b31b357 | 7713 | and then N /= First (Expressions (P)) |
7714 | then | |
7715 | return False; | |
e977c0cf | 7716 | end if; |
7717 | ||
20cf157b | 7718 | -- If within a case expression, and not part of the expression, |
7719 | -- then return False, since a particular dependent expression | |
7720 | -- may not always be elaborated | |
e977c0cf | 7721 | |
7722 | if Nkind (P) = N_Case_Expression | |
7723 | and then N /= Expression (P) | |
7724 | then | |
7725 | return False; | |
7b31b357 | 7726 | end if; |
7727 | ||
20cf157b | 7728 | -- While traversing the parent chain, if node N belongs to a |
7729 | -- statement, then it may never appear in a declarative region. | |
7870823d | 7730 | |
7731 | if Nkind (P) in N_Statement_Other_Than_Procedure_Call | |
7732 | or else Nkind (P) = N_Procedure_Call_Statement | |
7733 | then | |
7734 | return False; | |
7735 | end if; | |
7736 | ||
7b31b357 | 7737 | -- If we are at a declaration, record it and exit |
7738 | ||
7870823d | 7739 | if Nkind (P) in N_Declaration |
7740 | and then Nkind (P) not in N_Subprogram_Specification | |
7741 | then | |
7742 | N_Decl := P; | |
7743 | exit; | |
7744 | end if; | |
7745 | ||
7746 | P := Parent (P); | |
7747 | end loop; | |
7748 | ||
7749 | if No (N_Decl) then | |
7750 | return False; | |
7751 | end if; | |
7752 | ||
7753 | return List_Containing (N_Decl) = Declarations (S_Par); | |
7754 | end; | |
7b31b357 | 7755 | end Safe_To_Capture_In_Parameter_Value; |
84d0d4a5 | 7756 | |
7757 | ------------------- | |
7758 | -- Mark_Non_Null -- | |
7759 | ------------------- | |
7760 | ||
7761 | procedure Mark_Non_Null is | |
7762 | begin | |
7870823d | 7763 | -- Only case of interest is if node N is an entity name |
7764 | ||
84d0d4a5 | 7765 | if Is_Entity_Name (N) then |
7870823d | 7766 | |
7767 | -- For sure, we want to clear an indication that this is known to | |
39a0c1d3 | 7768 | -- be null, since if we get past this check, it definitely is not. |
7870823d | 7769 | |
84d0d4a5 | 7770 | Set_Is_Known_Null (Entity (N), False); |
7771 | ||
7870823d | 7772 | -- We can mark the entity as known to be non-null if either it is |
7773 | -- safe to capture the value, or in the case of an IN parameter, | |
7774 | -- which is a constant, if the check we just installed is in the | |
7775 | -- declarative region of the subprogram body. In this latter case, | |
7b31b357 | 7776 | -- a check is decisive for the rest of the body if the expression |
7777 | -- is sure to be elaborated, since we know we have to elaborate | |
7778 | -- all declarations before executing the body. | |
7779 | ||
7780 | -- Couldn't this always be part of Safe_To_Capture_Value ??? | |
7870823d | 7781 | |
7782 | if Safe_To_Capture_Value (N, Entity (N)) | |
7b31b357 | 7783 | or else Safe_To_Capture_In_Parameter_Value |
7870823d | 7784 | then |
7785 | Set_Is_Known_Non_Null (Entity (N)); | |
84d0d4a5 | 7786 | end if; |
7787 | end if; | |
7788 | end Mark_Non_Null; | |
7789 | ||
7790 | -- Start of processing for Install_Null_Excluding_Check | |
fa7497e8 | 7791 | |
7792 | begin | |
c9bbc06b | 7793 | -- No need to add null-excluding checks when the tree may not be fully |
7794 | -- decorated. | |
7795 | ||
7796 | if Serious_Errors_Detected > 0 then | |
7797 | return; | |
7798 | end if; | |
7799 | ||
84d0d4a5 | 7800 | pragma Assert (Is_Access_Type (Typ)); |
fa7497e8 | 7801 | |
46e32b5e | 7802 | -- No check inside a generic, check will be emitted in instance |
fa7497e8 | 7803 | |
84d0d4a5 | 7804 | if Inside_A_Generic then |
fa7497e8 | 7805 | return; |
84d0d4a5 | 7806 | end if; |
7807 | ||
7808 | -- No check needed if known to be non-null | |
7809 | ||
7810 | if Known_Non_Null (N) then | |
05fcfafb | 7811 | return; |
84d0d4a5 | 7812 | end if; |
fa7497e8 | 7813 | |
84d0d4a5 | 7814 | -- If known to be null, here is where we generate a compile time check |
7815 | ||
7816 | if Known_Null (N) then | |
d16989f1 | 7817 | |
20cf157b | 7818 | -- Avoid generating warning message inside init procs. In SPARK mode |
7819 | -- we can go ahead and call Apply_Compile_Time_Constraint_Error | |
46e32b5e | 7820 | -- since it will be turned into an error in any case. |
d16989f1 | 7821 | |
46e32b5e | 7822 | if (not Inside_Init_Proc or else SPARK_Mode = On) |
7823 | ||
28d5d68f | 7824 | -- Do not emit the warning within a conditional expression, |
7825 | -- where the expression might not be evaluated, and the warning | |
7826 | -- appear as extraneous noise. | |
46e32b5e | 7827 | |
7828 | and then not Within_Case_Or_If_Expression (N) | |
7829 | then | |
d16989f1 | 7830 | Apply_Compile_Time_Constraint_Error |
4098232e | 7831 | (N, "null value not allowed here??", CE_Access_Check_Failed); |
46e32b5e | 7832 | |
7833 | -- Remaining cases, where we silently insert the raise | |
7834 | ||
d16989f1 | 7835 | else |
7836 | Insert_Action (N, | |
7837 | Make_Raise_Constraint_Error (Loc, | |
7838 | Reason => CE_Access_Check_Failed)); | |
7839 | end if; | |
7840 | ||
84d0d4a5 | 7841 | Mark_Non_Null; |
7842 | return; | |
7843 | end if; | |
7844 | ||
7845 | -- If entity is never assigned, for sure a warning is appropriate | |
7846 | ||
7847 | if Is_Entity_Name (N) then | |
7848 | Check_Unset_Reference (N); | |
fa7497e8 | 7849 | end if; |
84d0d4a5 | 7850 | |
7851 | -- No check needed if checks are suppressed on the range. Note that we | |
7852 | -- don't set Is_Known_Non_Null in this case (we could legitimately do | |
7853 | -- so, since the program is erroneous, but we don't like to casually | |
7854 | -- propagate such conclusions from erroneosity). | |
7855 | ||
7856 | if Access_Checks_Suppressed (Typ) then | |
7857 | return; | |
7858 | end if; | |
7859 | ||
2af58f67 | 7860 | -- No check needed for access to concurrent record types generated by |
7861 | -- the expander. This is not just an optimization (though it does indeed | |
7862 | -- remove junk checks). It also avoids generation of junk warnings. | |
7863 | ||
7864 | if Nkind (N) in N_Has_Chars | |
7865 | and then Chars (N) = Name_uObject | |
7866 | and then Is_Concurrent_Record_Type | |
7867 | (Directly_Designated_Type (Etype (N))) | |
7868 | then | |
7869 | return; | |
7870 | end if; | |
7871 | ||
228836e8 | 7872 | -- No check needed in interface thunks since the runtime check is |
7873 | -- already performed at the caller side. | |
7874 | ||
7875 | if Is_Thunk (Current_Scope) then | |
7876 | return; | |
7877 | end if; | |
7878 | ||
472ea160 | 7879 | -- No check needed for the Get_Current_Excep.all.all idiom generated by |
7880 | -- the expander within exception handlers, since we know that the value | |
7881 | -- can never be null. | |
7882 | ||
7883 | -- Is this really the right way to do this? Normally we generate such | |
7884 | -- code in the expander with checks off, and that's how we suppress this | |
7885 | -- kind of junk check ??? | |
7886 | ||
7887 | if Nkind (N) = N_Function_Call | |
7888 | and then Nkind (Name (N)) = N_Explicit_Dereference | |
7889 | and then Nkind (Prefix (Name (N))) = N_Identifier | |
7890 | and then Is_RTE (Entity (Prefix (Name (N))), RE_Get_Current_Excep) | |
7891 | then | |
7892 | return; | |
7893 | end if; | |
7894 | ||
84d0d4a5 | 7895 | -- Otherwise install access check |
7896 | ||
7897 | Insert_Action (N, | |
7898 | Make_Raise_Constraint_Error (Loc, | |
7899 | Condition => | |
7900 | Make_Op_Eq (Loc, | |
7901 | Left_Opnd => Duplicate_Subexpr_Move_Checks (N), | |
7902 | Right_Opnd => Make_Null (Loc)), | |
7903 | Reason => CE_Access_Check_Failed)); | |
7904 | ||
7905 | Mark_Non_Null; | |
fa7497e8 | 7906 | end Install_Null_Excluding_Check; |
7907 | ||
7e933b61 | 7908 | ----------------------------------------- |
7909 | -- Install_Primitive_Elaboration_Check -- | |
7910 | ----------------------------------------- | |
7911 | ||
7912 | procedure Install_Primitive_Elaboration_Check (Subp_Body : Node_Id) is | |
7e933b61 | 7913 | function Within_Compilation_Unit_Instance |
7914 | (Subp_Id : Entity_Id) return Boolean; | |
7915 | -- Determine whether subprogram Subp_Id appears within an instance which | |
7916 | -- acts as a compilation unit. | |
7917 | ||
7918 | -------------------------------------- | |
7919 | -- Within_Compilation_Unit_Instance -- | |
7920 | -------------------------------------- | |
7921 | ||
7922 | function Within_Compilation_Unit_Instance | |
7923 | (Subp_Id : Entity_Id) return Boolean | |
7924 | is | |
7925 | Pack : Entity_Id; | |
7926 | ||
7927 | begin | |
7928 | -- Examine the scope chain looking for a compilation-unit-level | |
7929 | -- instance. | |
7930 | ||
7931 | Pack := Scope (Subp_Id); | |
7932 | while Present (Pack) and then Pack /= Standard_Standard loop | |
7933 | if Ekind (Pack) = E_Package | |
7934 | and then Is_Generic_Instance (Pack) | |
7935 | and then Nkind (Parent (Unit_Declaration_Node (Pack))) = | |
7936 | N_Compilation_Unit | |
7937 | then | |
7938 | return True; | |
7939 | end if; | |
7940 | ||
7941 | Pack := Scope (Pack); | |
7942 | end loop; | |
7943 | ||
7944 | return False; | |
7945 | end Within_Compilation_Unit_Instance; | |
7946 | ||
7947 | -- Local declarations | |
7948 | ||
7949 | Context : constant Node_Id := Parent (Subp_Body); | |
7950 | Loc : constant Source_Ptr := Sloc (Subp_Body); | |
7951 | Subp_Id : constant Entity_Id := Unique_Defining_Entity (Subp_Body); | |
7952 | Subp_Decl : constant Node_Id := Unit_Declaration_Node (Subp_Id); | |
7953 | ||
e2293a63 | 7954 | Decls : List_Id; |
7955 | Flag_Id : Entity_Id; | |
7956 | Set_Ins : Node_Id; | |
7957 | Set_Stmt : Node_Id; | |
7958 | Tag_Typ : Entity_Id; | |
7e933b61 | 7959 | |
7960 | -- Start of processing for Install_Primitive_Elaboration_Check | |
7961 | ||
7962 | begin | |
7963 | -- Do not generate an elaboration check in compilation modes where | |
7964 | -- expansion is not desirable. | |
7965 | ||
7966 | if ASIS_Mode or GNATprove_Mode then | |
7967 | return; | |
7968 | ||
f0e731f2 | 7969 | -- Do not generate an elaboration check if all checks have been |
7970 | -- suppressed. | |
62c62e4b | 7971 | |
f0e731f2 | 7972 | elsif Suppress_Checks then |
62c62e4b | 7973 | return; |
7974 | ||
7e933b61 | 7975 | -- Do not generate an elaboration check if the related subprogram is |
7976 | -- not subjected to accessibility checks. | |
7977 | ||
7978 | elsif Elaboration_Checks_Suppressed (Subp_Id) then | |
7979 | return; | |
f0e731f2 | 7980 | |
7981 | -- Do not generate an elaboration check if such code is not desirable | |
7982 | ||
7983 | elsif Restriction_Active (No_Elaboration_Code) then | |
7984 | return; | |
7e933b61 | 7985 | |
77b577f9 | 7986 | -- Do not generate an elaboration check if exceptions cannot be used, |
7987 | -- caught, or propagated. | |
7988 | ||
7989 | elsif not Exceptions_OK then | |
7990 | return; | |
7991 | ||
7e933b61 | 7992 | -- Do not consider subprograms which act as compilation units, because |
7993 | -- they cannot be the target of a dispatching call. | |
7994 | ||
7995 | elsif Nkind (Context) = N_Compilation_Unit then | |
7996 | return; | |
7997 | ||
e2293a63 | 7998 | -- Do not consider anything other than nonabstract library-level source |
7999 | -- primitives. | |
7e933b61 | 8000 | |
8001 | elsif not | |
8002 | (Comes_From_Source (Subp_Id) | |
8003 | and then Is_Library_Level_Entity (Subp_Id) | |
8004 | and then Is_Primitive (Subp_Id) | |
8005 | and then not Is_Abstract_Subprogram (Subp_Id)) | |
8006 | then | |
8007 | return; | |
8008 | ||
8009 | -- Do not consider inlined primitives, because once the body is inlined | |
8010 | -- the reference to the elaboration flag will be out of place and will | |
8011 | -- result in an undefined symbol. | |
8012 | ||
8013 | elsif Is_Inlined (Subp_Id) or else Has_Pragma_Inline (Subp_Id) then | |
8014 | return; | |
8015 | ||
8016 | -- Do not generate a duplicate elaboration check. This happens only in | |
8017 | -- the case of primitives completed by an expression function, as the | |
8018 | -- corresponding body is apparently analyzed and expanded twice. | |
8019 | ||
8020 | elsif Analyzed (Subp_Body) then | |
8021 | return; | |
8022 | ||
8023 | -- Do not consider primitives which occur within an instance that acts | |
8024 | -- as a compilation unit. Such an instance defines its spec and body out | |
8025 | -- of order (body is first) within the tree, which causes the reference | |
8026 | -- to the elaboration flag to appear as an undefined symbol. | |
8027 | ||
8028 | elsif Within_Compilation_Unit_Instance (Subp_Id) then | |
8029 | return; | |
8030 | end if; | |
8031 | ||
8032 | Tag_Typ := Find_Dispatching_Type (Subp_Id); | |
8033 | ||
8034 | -- Only tagged primitives may be the target of a dispatching call | |
8035 | ||
8036 | if No (Tag_Typ) then | |
8037 | return; | |
8038 | ||
8039 | -- Do not consider finalization-related primitives, because they may | |
8040 | -- need to be called while elaboration is taking place. | |
8041 | ||
8042 | elsif Is_Controlled (Tag_Typ) | |
8043 | and then Nam_In (Chars (Subp_Id), Name_Adjust, | |
8044 | Name_Finalize, | |
8045 | Name_Initialize) | |
8046 | then | |
8047 | return; | |
8048 | end if; | |
8049 | ||
8050 | -- Create the declaration of the elaboration flag. The name carries a | |
8051 | -- unique counter in case of name overloading. | |
8052 | ||
8053 | Flag_Id := | |
8054 | Make_Defining_Identifier (Loc, | |
fe48a434 | 8055 | Chars => New_External_Name (Chars (Subp_Id), 'E', -1)); |
7e933b61 | 8056 | Set_Is_Frozen (Flag_Id); |
8057 | ||
8058 | -- Insert the declaration of the elaboration flag in front of the | |
8059 | -- primitive spec and analyze it in the proper context. | |
8060 | ||
8061 | Push_Scope (Scope (Subp_Id)); | |
8062 | ||
8063 | -- Generate: | |
fe48a434 | 8064 | -- E : Boolean := False; |
7e933b61 | 8065 | |
8066 | Insert_Action (Subp_Decl, | |
8067 | Make_Object_Declaration (Loc, | |
8068 | Defining_Identifier => Flag_Id, | |
8069 | Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc), | |
8070 | Expression => New_Occurrence_Of (Standard_False, Loc))); | |
8071 | Pop_Scope; | |
8072 | ||
8073 | -- Prevent the compiler from optimizing the elaboration check by killing | |
8074 | -- the current value of the flag and the associated assignment. | |
8075 | ||
8076 | Set_Current_Value (Flag_Id, Empty); | |
8077 | Set_Last_Assignment (Flag_Id, Empty); | |
8078 | ||
8079 | -- Add a check at the top of the body declarations to ensure that the | |
8080 | -- elaboration flag has been set. | |
8081 | ||
8082 | Decls := Declarations (Subp_Body); | |
8083 | ||
8084 | if No (Decls) then | |
8085 | Decls := New_List; | |
8086 | Set_Declarations (Subp_Body, Decls); | |
8087 | end if; | |
8088 | ||
8089 | -- Generate: | |
8090 | -- if not F then | |
8091 | -- raise Program_Error with "access before elaboration"; | |
8092 | -- end if; | |
8093 | ||
8094 | Prepend_To (Decls, | |
8095 | Make_Raise_Program_Error (Loc, | |
8096 | Condition => | |
8097 | Make_Op_Not (Loc, | |
8098 | Right_Opnd => New_Occurrence_Of (Flag_Id, Loc)), | |
8099 | Reason => PE_Access_Before_Elaboration)); | |
8100 | ||
8101 | Analyze (First (Decls)); | |
8102 | ||
8103 | -- Set the elaboration flag once the body has been elaborated. Insert | |
8104 | -- the statement after the subprogram stub when the primitive body is | |
8105 | -- a subunit. | |
8106 | ||
8107 | if Nkind (Context) = N_Subunit then | |
8108 | Set_Ins := Corresponding_Stub (Context); | |
8109 | else | |
8110 | Set_Ins := Subp_Body; | |
8111 | end if; | |
8112 | ||
8113 | -- Generate: | |
fe48a434 | 8114 | -- E := True; |
7e933b61 | 8115 | |
e2293a63 | 8116 | Set_Stmt := |
7e933b61 | 8117 | Make_Assignment_Statement (Loc, |
8118 | Name => New_Occurrence_Of (Flag_Id, Loc), | |
e2293a63 | 8119 | Expression => New_Occurrence_Of (Standard_True, Loc)); |
8120 | ||
8121 | -- Mark the assignment statement as elaboration code. This allows the | |
8122 | -- early call region mechanism (see Sem_Elab) to properly ignore such | |
8123 | -- assignments even though they are non-preelaborable code. | |
8124 | ||
8125 | Set_Is_Elaboration_Code (Set_Stmt); | |
8126 | ||
8127 | Insert_After_And_Analyze (Set_Ins, Set_Stmt); | |
7e933b61 | 8128 | end Install_Primitive_Elaboration_Check; |
8129 | ||
ee6ba406 | 8130 | -------------------------- |
8131 | -- Install_Static_Check -- | |
8132 | -------------------------- | |
8133 | ||
8134 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is | |
cda40848 | 8135 | Stat : constant Boolean := Is_OK_Static_Expression (R_Cno); |
ee6ba406 | 8136 | Typ : constant Entity_Id := Etype (R_Cno); |
8137 | ||
8138 | begin | |
f15731c4 | 8139 | Rewrite (R_Cno, |
8140 | Make_Raise_Constraint_Error (Loc, | |
8141 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 8142 | Set_Analyzed (R_Cno); |
8143 | Set_Etype (R_Cno, Typ); | |
8144 | Set_Raises_Constraint_Error (R_Cno); | |
8145 | Set_Is_Static_Expression (R_Cno, Stat); | |
840ab274 | 8146 | |
8147 | -- Now deal with possible local raise handling | |
8148 | ||
8149 | Possible_Local_Raise (R_Cno, Standard_Constraint_Error); | |
ee6ba406 | 8150 | end Install_Static_Check; |
8151 | ||
3cce7f32 | 8152 | ------------------------- |
8153 | -- Is_Check_Suppressed -- | |
8154 | ------------------------- | |
8155 | ||
8156 | function Is_Check_Suppressed (E : Entity_Id; C : Check_Id) return Boolean is | |
8157 | Ptr : Suppress_Stack_Entry_Ptr; | |
8158 | ||
8159 | begin | |
8160 | -- First search the local entity suppress stack. We search this from the | |
8161 | -- top of the stack down so that we get the innermost entry that applies | |
8162 | -- to this case if there are nested entries. | |
8163 | ||
8164 | Ptr := Local_Suppress_Stack_Top; | |
8165 | while Ptr /= null loop | |
8166 | if (Ptr.Entity = Empty or else Ptr.Entity = E) | |
8167 | and then (Ptr.Check = All_Checks or else Ptr.Check = C) | |
8168 | then | |
8169 | return Ptr.Suppress; | |
8170 | end if; | |
8171 | ||
8172 | Ptr := Ptr.Prev; | |
8173 | end loop; | |
8174 | ||
8175 | -- Now search the global entity suppress table for a matching entry. | |
8176 | -- We also search this from the top down so that if there are multiple | |
8177 | -- pragmas for the same entity, the last one applies (not clear what | |
8178 | -- or whether the RM specifies this handling, but it seems reasonable). | |
8179 | ||
8180 | Ptr := Global_Suppress_Stack_Top; | |
8181 | while Ptr /= null loop | |
8182 | if (Ptr.Entity = Empty or else Ptr.Entity = E) | |
8183 | and then (Ptr.Check = All_Checks or else Ptr.Check = C) | |
8184 | then | |
8185 | return Ptr.Suppress; | |
8186 | end if; | |
8187 | ||
8188 | Ptr := Ptr.Prev; | |
8189 | end loop; | |
8190 | ||
8191 | -- If we did not find a matching entry, then use the normal scope | |
8192 | -- suppress value after all (actually this will be the global setting | |
8193 | -- since it clearly was not overridden at any point). For a predefined | |
8194 | -- check, we test the specific flag. For a user defined check, we check | |
8195 | -- the All_Checks flag. The Overflow flag requires special handling to | |
fe48a434 | 8196 | -- deal with the General vs Assertion case. |
3cce7f32 | 8197 | |
8198 | if C = Overflow_Check then | |
8199 | return Overflow_Checks_Suppressed (Empty); | |
fe48a434 | 8200 | |
3cce7f32 | 8201 | elsif C in Predefined_Check_Id then |
8202 | return Scope_Suppress.Suppress (C); | |
fe48a434 | 8203 | |
3cce7f32 | 8204 | else |
8205 | return Scope_Suppress.Suppress (All_Checks); | |
8206 | end if; | |
8207 | end Is_Check_Suppressed; | |
8208 | ||
9dfe12ae | 8209 | --------------------- |
8210 | -- Kill_All_Checks -- | |
8211 | --------------------- | |
8212 | ||
8213 | procedure Kill_All_Checks is | |
8214 | begin | |
8215 | if Debug_Flag_CC then | |
8216 | w ("Kill_All_Checks"); | |
8217 | end if; | |
8218 | ||
feff2f05 | 8219 | -- We reset the number of saved checks to zero, and also modify all |
8220 | -- stack entries for statement ranges to indicate that the number of | |
8221 | -- checks at each level is now zero. | |
9dfe12ae | 8222 | |
8223 | Num_Saved_Checks := 0; | |
8224 | ||
96da3284 | 8225 | -- Note: the Int'Min here avoids any possibility of J being out of |
8226 | -- range when called from e.g. Conditional_Statements_Begin. | |
8227 | ||
8228 | for J in 1 .. Int'Min (Saved_Checks_TOS, Saved_Checks_Stack'Last) loop | |
9dfe12ae | 8229 | Saved_Checks_Stack (J) := 0; |
8230 | end loop; | |
8231 | end Kill_All_Checks; | |
8232 | ||
8233 | ----------------- | |
8234 | -- Kill_Checks -- | |
8235 | ----------------- | |
8236 | ||
8237 | procedure Kill_Checks (V : Entity_Id) is | |
8238 | begin | |
8239 | if Debug_Flag_CC then | |
8240 | w ("Kill_Checks for entity", Int (V)); | |
8241 | end if; | |
8242 | ||
8243 | for J in 1 .. Num_Saved_Checks loop | |
8244 | if Saved_Checks (J).Entity = V then | |
8245 | if Debug_Flag_CC then | |
8246 | w (" Checks killed for saved check ", J); | |
8247 | end if; | |
8248 | ||
8249 | Saved_Checks (J).Killed := True; | |
8250 | end if; | |
8251 | end loop; | |
8252 | end Kill_Checks; | |
8253 | ||
ee6ba406 | 8254 | ------------------------------ |
8255 | -- Length_Checks_Suppressed -- | |
8256 | ------------------------------ | |
8257 | ||
8258 | function Length_Checks_Suppressed (E : Entity_Id) return Boolean is | |
8259 | begin | |
9dfe12ae | 8260 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
8261 | return Is_Check_Suppressed (E, Length_Check); | |
8262 | else | |
fafc6b97 | 8263 | return Scope_Suppress.Suppress (Length_Check); |
9dfe12ae | 8264 | end if; |
ee6ba406 | 8265 | end Length_Checks_Suppressed; |
8266 | ||
3cce7f32 | 8267 | ----------------------- |
8268 | -- Make_Bignum_Block -- | |
8269 | ----------------------- | |
8270 | ||
8271 | function Make_Bignum_Block (Loc : Source_Ptr) return Node_Id is | |
8272 | M : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uM); | |
3cce7f32 | 8273 | begin |
8274 | return | |
8275 | Make_Block_Statement (Loc, | |
97c15ab0 | 8276 | Declarations => |
8277 | New_List (Build_SS_Mark_Call (Loc, M)), | |
3cce7f32 | 8278 | Handled_Statement_Sequence => |
8279 | Make_Handled_Sequence_Of_Statements (Loc, | |
97c15ab0 | 8280 | Statements => New_List (Build_SS_Release_Call (Loc, M)))); |
3cce7f32 | 8281 | end Make_Bignum_Block; |
8282 | ||
0df9d43f | 8283 | ---------------------------------- |
8284 | -- Minimize_Eliminate_Overflows -- | |
8285 | ---------------------------------- | |
3cce7f32 | 8286 | |
f32c377d | 8287 | -- This is a recursive routine that is called at the top of an expression |
8288 | -- tree to properly process overflow checking for a whole subtree by making | |
8289 | -- recursive calls to process operands. This processing may involve the use | |
8290 | -- of bignum or long long integer arithmetic, which will change the types | |
8291 | -- of operands and results. That's why we can't do this bottom up (since | |
21a55437 | 8292 | -- it would interfere with semantic analysis). |
f32c377d | 8293 | |
21a55437 | 8294 | -- What happens is that if MINIMIZED/ELIMINATED mode is in effect then |
0df9d43f | 8295 | -- the operator expansion routines, as well as the expansion routines for |
8296 | -- if/case expression, do nothing (for the moment) except call the routine | |
8297 | -- to apply the overflow check (Apply_Arithmetic_Overflow_Check). That | |
8298 | -- routine does nothing for non top-level nodes, so at the point where the | |
8299 | -- call is made for the top level node, the entire expression subtree has | |
8300 | -- not been expanded, or processed for overflow. All that has to happen as | |
8301 | -- a result of the top level call to this routine. | |
f32c377d | 8302 | |
8303 | -- As noted above, the overflow processing works by making recursive calls | |
8304 | -- for the operands, and figuring out what to do, based on the processing | |
8305 | -- of these operands (e.g. if a bignum operand appears, the parent op has | |
8306 | -- to be done in bignum mode), and the determined ranges of the operands. | |
8307 | ||
8308 | -- After possible rewriting of a constituent subexpression node, a call is | |
4fb5f0a0 | 8309 | -- made to either reexpand the node (if nothing has changed) or reanalyze |
21a55437 | 8310 | -- the node (if it has been modified by the overflow check processing). The |
8311 | -- Analyzed_Flag is set to False before the reexpand/reanalyze. To avoid | |
8312 | -- a recursive call into the whole overflow apparatus, an important rule | |
0df9d43f | 8313 | -- for this call is that the overflow handling mode must be temporarily set |
8314 | -- to STRICT. | |
f32c377d | 8315 | |
0df9d43f | 8316 | procedure Minimize_Eliminate_Overflows |
61016a7a | 8317 | (N : Node_Id; |
8318 | Lo : out Uint; | |
8319 | Hi : out Uint; | |
8320 | Top_Level : Boolean) | |
3cce7f32 | 8321 | is |
0326b4d4 | 8322 | Rtyp : constant Entity_Id := Etype (N); |
8323 | pragma Assert (Is_Signed_Integer_Type (Rtyp)); | |
8324 | -- Result type, must be a signed integer type | |
3cce7f32 | 8325 | |
db415383 | 8326 | Check_Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
3cce7f32 | 8327 | pragma Assert (Check_Mode in Minimized_Or_Eliminated); |
8328 | ||
8329 | Loc : constant Source_Ptr := Sloc (N); | |
8330 | ||
8331 | Rlo, Rhi : Uint; | |
0326b4d4 | 8332 | -- Ranges of values for right operand (operator case) |
3cce7f32 | 8333 | |
16149377 | 8334 | Llo : Uint := No_Uint; -- initialize to prevent warning |
8335 | Lhi : Uint := No_Uint; -- initialize to prevent warning | |
0326b4d4 | 8336 | -- Ranges of values for left operand (operator case) |
3cce7f32 | 8337 | |
49b3a812 | 8338 | LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); |
8339 | -- Operands and results are of this type when we convert | |
8340 | ||
0326b4d4 | 8341 | LLLo : constant Uint := Intval (Type_Low_Bound (LLIB)); |
8342 | LLHi : constant Uint := Intval (Type_High_Bound (LLIB)); | |
3cce7f32 | 8343 | -- Bounds of Long_Long_Integer |
8344 | ||
8345 | Binary : constant Boolean := Nkind (N) in N_Binary_Op; | |
8346 | -- Indicates binary operator case | |
8347 | ||
8348 | OK : Boolean; | |
8349 | -- Used in call to Determine_Range | |
8350 | ||
61016a7a | 8351 | Bignum_Operands : Boolean; |
8352 | -- Set True if one or more operands is already of type Bignum, meaning | |
8353 | -- that for sure (regardless of Top_Level setting) we are committed to | |
0326b4d4 | 8354 | -- doing the operation in Bignum mode (or in the case of a case or if |
21a55437 | 8355 | -- expression, converting all the dependent expressions to Bignum). |
0326b4d4 | 8356 | |
8357 | Long_Long_Integer_Operands : Boolean; | |
21a55437 | 8358 | -- Set True if one or more operands is already of type Long_Long_Integer |
0326b4d4 | 8359 | -- which means that if the result is known to be in the result type |
8360 | -- range, then we must convert such operands back to the result type. | |
0df9d43f | 8361 | |
8362 | procedure Reanalyze (Typ : Entity_Id; Suppress : Boolean := False); | |
8363 | -- This is called when we have modified the node and we therefore need | |
8364 | -- to reanalyze it. It is important that we reset the mode to STRICT for | |
8365 | -- this reanalysis, since if we leave it in MINIMIZED or ELIMINATED mode | |
39a0c1d3 | 8366 | -- we would reenter this routine recursively which would not be good. |
0df9d43f | 8367 | -- The argument Suppress is set True if we also want to suppress |
8368 | -- overflow checking for the reexpansion (this is set when we know | |
8369 | -- overflow is not possible). Typ is the type for the reanalysis. | |
8370 | ||
8371 | procedure Reexpand (Suppress : Boolean := False); | |
8372 | -- This is like Reanalyze, but does not do the Analyze step, it only | |
8373 | -- does a reexpansion. We do this reexpansion in STRICT mode, so that | |
8374 | -- instead of reentering the MINIMIZED/ELIMINATED mode processing, we | |
8375 | -- follow the normal expansion path (e.g. converting A**4 to A**2**2). | |
8376 | -- Note that skipping reanalysis is not just an optimization, testing | |
8377 | -- has showed up several complex cases in which reanalyzing an already | |
8378 | -- analyzed node causes incorrect behavior. | |
4fb5f0a0 | 8379 | |
0326b4d4 | 8380 | function In_Result_Range return Boolean; |
8381 | -- Returns True iff Lo .. Hi are within range of the result type | |
61016a7a | 8382 | |
2fe22c69 | 8383 | procedure Max (A : in out Uint; B : Uint); |
21a55437 | 8384 | -- If A is No_Uint, sets A to B, else to UI_Max (A, B) |
2fe22c69 | 8385 | |
8386 | procedure Min (A : in out Uint; B : Uint); | |
21a55437 | 8387 | -- If A is No_Uint, sets A to B, else to UI_Min (A, B) |
2fe22c69 | 8388 | |
0326b4d4 | 8389 | --------------------- |
8390 | -- In_Result_Range -- | |
8391 | --------------------- | |
8392 | ||
8393 | function In_Result_Range return Boolean is | |
8394 | begin | |
f32c377d | 8395 | if Lo = No_Uint or else Hi = No_Uint then |
8396 | return False; | |
8397 | ||
cda40848 | 8398 | elsif Is_OK_Static_Subtype (Etype (N)) then |
0326b4d4 | 8399 | return Lo >= Expr_Value (Type_Low_Bound (Rtyp)) |
8400 | and then | |
8401 | Hi <= Expr_Value (Type_High_Bound (Rtyp)); | |
f32c377d | 8402 | |
0326b4d4 | 8403 | else |
8404 | return Lo >= Expr_Value (Type_Low_Bound (Base_Type (Rtyp))) | |
8405 | and then | |
8406 | Hi <= Expr_Value (Type_High_Bound (Base_Type (Rtyp))); | |
8407 | end if; | |
8408 | end In_Result_Range; | |
8409 | ||
2fe22c69 | 8410 | --------- |
8411 | -- Max -- | |
8412 | --------- | |
8413 | ||
8414 | procedure Max (A : in out Uint; B : Uint) is | |
8415 | begin | |
8416 | if A = No_Uint or else B > A then | |
8417 | A := B; | |
8418 | end if; | |
8419 | end Max; | |
8420 | ||
8421 | --------- | |
8422 | -- Min -- | |
8423 | --------- | |
8424 | ||
8425 | procedure Min (A : in out Uint; B : Uint) is | |
8426 | begin | |
8427 | if A = No_Uint or else B < A then | |
8428 | A := B; | |
8429 | end if; | |
8430 | end Min; | |
8431 | ||
0df9d43f | 8432 | --------------- |
8433 | -- Reanalyze -- | |
8434 | --------------- | |
8435 | ||
8436 | procedure Reanalyze (Typ : Entity_Id; Suppress : Boolean := False) is | |
db415383 | 8437 | Svg : constant Overflow_Mode_Type := |
8438 | Scope_Suppress.Overflow_Mode_General; | |
8439 | Sva : constant Overflow_Mode_Type := | |
8440 | Scope_Suppress.Overflow_Mode_Assertions; | |
0df9d43f | 8441 | Svo : constant Boolean := |
8442 | Scope_Suppress.Suppress (Overflow_Check); | |
8443 | ||
8444 | begin | |
db415383 | 8445 | Scope_Suppress.Overflow_Mode_General := Strict; |
8446 | Scope_Suppress.Overflow_Mode_Assertions := Strict; | |
0df9d43f | 8447 | |
8448 | if Suppress then | |
8449 | Scope_Suppress.Suppress (Overflow_Check) := True; | |
8450 | end if; | |
8451 | ||
8452 | Analyze_And_Resolve (N, Typ); | |
8453 | ||
2b108e18 | 8454 | Scope_Suppress.Suppress (Overflow_Check) := Svo; |
8455 | Scope_Suppress.Overflow_Mode_General := Svg; | |
8456 | Scope_Suppress.Overflow_Mode_Assertions := Sva; | |
0df9d43f | 8457 | end Reanalyze; |
8458 | ||
4fb5f0a0 | 8459 | -------------- |
8460 | -- Reexpand -- | |
8461 | -------------- | |
8462 | ||
0df9d43f | 8463 | procedure Reexpand (Suppress : Boolean := False) is |
db415383 | 8464 | Svg : constant Overflow_Mode_Type := |
8465 | Scope_Suppress.Overflow_Mode_General; | |
8466 | Sva : constant Overflow_Mode_Type := | |
8467 | Scope_Suppress.Overflow_Mode_Assertions; | |
0df9d43f | 8468 | Svo : constant Boolean := |
8469 | Scope_Suppress.Suppress (Overflow_Check); | |
8470 | ||
4fb5f0a0 | 8471 | begin |
db415383 | 8472 | Scope_Suppress.Overflow_Mode_General := Strict; |
8473 | Scope_Suppress.Overflow_Mode_Assertions := Strict; | |
4fb5f0a0 | 8474 | Set_Analyzed (N, False); |
0df9d43f | 8475 | |
8476 | if Suppress then | |
8477 | Scope_Suppress.Suppress (Overflow_Check) := True; | |
8478 | end if; | |
8479 | ||
4fb5f0a0 | 8480 | Expand (N); |
0df9d43f | 8481 | |
2b108e18 | 8482 | Scope_Suppress.Suppress (Overflow_Check) := Svo; |
8483 | Scope_Suppress.Overflow_Mode_General := Svg; | |
8484 | Scope_Suppress.Overflow_Mode_Assertions := Sva; | |
4fb5f0a0 | 8485 | end Reexpand; |
8486 | ||
0df9d43f | 8487 | -- Start of processing for Minimize_Eliminate_Overflows |
2fe22c69 | 8488 | |
3cce7f32 | 8489 | begin |
02038e4e | 8490 | -- Default initialize Lo and Hi since these are not guaranteed to be |
8491 | -- set otherwise. | |
8492 | ||
8493 | Lo := No_Uint; | |
8494 | Hi := No_Uint; | |
8495 | ||
0326b4d4 | 8496 | -- Case where we do not have a signed integer arithmetic operation |
3cce7f32 | 8497 | |
8498 | if not Is_Signed_Integer_Arithmetic_Op (N) then | |
8499 | ||
8500 | -- Use the normal Determine_Range routine to get the range. We | |
8501 | -- don't require operands to be valid, invalid values may result in | |
8502 | -- rubbish results where the result has not been properly checked for | |
39a0c1d3 | 8503 | -- overflow, that's fine. |
3cce7f32 | 8504 | |
8505 | Determine_Range (N, OK, Lo, Hi, Assume_Valid => False); | |
8506 | ||
21a55437 | 8507 | -- If Determine_Range did not work (can this in fact happen? Not |
3cce7f32 | 8508 | -- clear but might as well protect), use type bounds. |
8509 | ||
8510 | if not OK then | |
8511 | Lo := Intval (Type_Low_Bound (Base_Type (Etype (N)))); | |
8512 | Hi := Intval (Type_High_Bound (Base_Type (Etype (N)))); | |
8513 | end if; | |
8514 | ||
8515 | -- If we don't have a binary operator, all we have to do is to set | |
20cf157b | 8516 | -- the Hi/Lo range, so we are done. |
3cce7f32 | 8517 | |
8518 | return; | |
8519 | ||
0326b4d4 | 8520 | -- Processing for if expression |
8521 | ||
92f1631f | 8522 | elsif Nkind (N) = N_If_Expression then |
0326b4d4 | 8523 | declare |
8524 | Then_DE : constant Node_Id := Next (First (Expressions (N))); | |
8525 | Else_DE : constant Node_Id := Next (Then_DE); | |
8526 | ||
8527 | begin | |
8528 | Bignum_Operands := False; | |
8529 | ||
0df9d43f | 8530 | Minimize_Eliminate_Overflows |
0326b4d4 | 8531 | (Then_DE, Lo, Hi, Top_Level => False); |
8532 | ||
8533 | if Lo = No_Uint then | |
8534 | Bignum_Operands := True; | |
8535 | end if; | |
8536 | ||
0df9d43f | 8537 | Minimize_Eliminate_Overflows |
0326b4d4 | 8538 | (Else_DE, Rlo, Rhi, Top_Level => False); |
8539 | ||
8540 | if Rlo = No_Uint then | |
8541 | Bignum_Operands := True; | |
8542 | else | |
8543 | Long_Long_Integer_Operands := | |
8544 | Etype (Then_DE) = LLIB or else Etype (Else_DE) = LLIB; | |
8545 | ||
8546 | Min (Lo, Rlo); | |
8547 | Max (Hi, Rhi); | |
8548 | end if; | |
8549 | ||
21a55437 | 8550 | -- If at least one of our operands is now Bignum, we must rebuild |
8551 | -- the if expression to use Bignum operands. We will analyze the | |
0326b4d4 | 8552 | -- rebuilt if expression with overflow checks off, since once we |
39a0c1d3 | 8553 | -- are in bignum mode, we are all done with overflow checks. |
0326b4d4 | 8554 | |
8555 | if Bignum_Operands then | |
8556 | Rewrite (N, | |
92f1631f | 8557 | Make_If_Expression (Loc, |
0326b4d4 | 8558 | Expressions => New_List ( |
8559 | Remove_Head (Expressions (N)), | |
8560 | Convert_To_Bignum (Then_DE), | |
8561 | Convert_To_Bignum (Else_DE)), | |
8562 | Is_Elsif => Is_Elsif (N))); | |
8563 | ||
0df9d43f | 8564 | Reanalyze (RTE (RE_Bignum), Suppress => True); |
0326b4d4 | 8565 | |
8566 | -- If we have no Long_Long_Integer operands, then we are in result | |
8567 | -- range, since it means that none of our operands felt the need | |
8568 | -- to worry about overflow (otherwise it would have already been | |
4fb5f0a0 | 8569 | -- converted to long long integer or bignum). We reexpand to |
8570 | -- complete the expansion of the if expression (but we do not | |
8571 | -- need to reanalyze). | |
0326b4d4 | 8572 | |
8573 | elsif not Long_Long_Integer_Operands then | |
8574 | Set_Do_Overflow_Check (N, False); | |
0df9d43f | 8575 | Reexpand; |
0326b4d4 | 8576 | |
8577 | -- Otherwise convert us to long long integer mode. Note that we | |
8578 | -- don't need any further overflow checking at this level. | |
8579 | ||
8580 | else | |
8581 | Convert_To_And_Rewrite (LLIB, Then_DE); | |
8582 | Convert_To_And_Rewrite (LLIB, Else_DE); | |
8583 | Set_Etype (N, LLIB); | |
f32c377d | 8584 | |
8585 | -- Now reanalyze with overflow checks off | |
8586 | ||
0326b4d4 | 8587 | Set_Do_Overflow_Check (N, False); |
0df9d43f | 8588 | Reanalyze (LLIB, Suppress => True); |
0326b4d4 | 8589 | end if; |
8590 | end; | |
8591 | ||
8592 | return; | |
8593 | ||
8594 | -- Here for case expression | |
8595 | ||
8596 | elsif Nkind (N) = N_Case_Expression then | |
8597 | Bignum_Operands := False; | |
8598 | Long_Long_Integer_Operands := False; | |
0326b4d4 | 8599 | |
8600 | declare | |
f32c377d | 8601 | Alt : Node_Id; |
0326b4d4 | 8602 | |
8603 | begin | |
8604 | -- Loop through expressions applying recursive call | |
8605 | ||
8606 | Alt := First (Alternatives (N)); | |
8607 | while Present (Alt) loop | |
8608 | declare | |
8609 | Aexp : constant Node_Id := Expression (Alt); | |
8610 | ||
8611 | begin | |
0df9d43f | 8612 | Minimize_Eliminate_Overflows |
0326b4d4 | 8613 | (Aexp, Lo, Hi, Top_Level => False); |
8614 | ||
8615 | if Lo = No_Uint then | |
8616 | Bignum_Operands := True; | |
8617 | elsif Etype (Aexp) = LLIB then | |
8618 | Long_Long_Integer_Operands := True; | |
8619 | end if; | |
8620 | end; | |
8621 | ||
8622 | Next (Alt); | |
8623 | end loop; | |
8624 | ||
8625 | -- If we have no bignum or long long integer operands, it means | |
8626 | -- that none of our dependent expressions could raise overflow. | |
8627 | -- In this case, we simply return with no changes except for | |
8628 | -- resetting the overflow flag, since we are done with overflow | |
4fb5f0a0 | 8629 | -- checks for this node. We will reexpand to get the needed |
8630 | -- expansion for the case expression, but we do not need to | |
21a55437 | 8631 | -- reanalyze, since nothing has changed. |
0326b4d4 | 8632 | |
f32c377d | 8633 | if not (Bignum_Operands or Long_Long_Integer_Operands) then |
0326b4d4 | 8634 | Set_Do_Overflow_Check (N, False); |
0df9d43f | 8635 | Reexpand (Suppress => True); |
0326b4d4 | 8636 | |
8637 | -- Otherwise we are going to rebuild the case expression using | |
8638 | -- either bignum or long long integer operands throughout. | |
8639 | ||
8640 | else | |
f32c377d | 8641 | declare |
8642 | Rtype : Entity_Id; | |
16149377 | 8643 | pragma Warnings (Off, Rtype); |
f32c377d | 8644 | New_Alts : List_Id; |
8645 | New_Exp : Node_Id; | |
8646 | ||
8647 | begin | |
8648 | New_Alts := New_List; | |
8649 | Alt := First (Alternatives (N)); | |
8650 | while Present (Alt) loop | |
8651 | if Bignum_Operands then | |
8652 | New_Exp := Convert_To_Bignum (Expression (Alt)); | |
8653 | Rtype := RTE (RE_Bignum); | |
8654 | else | |
8655 | New_Exp := Convert_To (LLIB, Expression (Alt)); | |
8656 | Rtype := LLIB; | |
8657 | end if; | |
0326b4d4 | 8658 | |
f32c377d | 8659 | Append_To (New_Alts, |
8660 | Make_Case_Expression_Alternative (Sloc (Alt), | |
8661 | Actions => No_List, | |
8662 | Discrete_Choices => Discrete_Choices (Alt), | |
8663 | Expression => New_Exp)); | |
0326b4d4 | 8664 | |
f32c377d | 8665 | Next (Alt); |
8666 | end loop; | |
0326b4d4 | 8667 | |
f32c377d | 8668 | Rewrite (N, |
8669 | Make_Case_Expression (Loc, | |
8670 | Expression => Expression (N), | |
8671 | Alternatives => New_Alts)); | |
0326b4d4 | 8672 | |
0df9d43f | 8673 | Reanalyze (Rtype, Suppress => True); |
f32c377d | 8674 | end; |
0326b4d4 | 8675 | end if; |
8676 | end; | |
8677 | ||
8678 | return; | |
8679 | end if; | |
8680 | ||
8681 | -- If we have an arithmetic operator we make recursive calls on the | |
3cce7f32 | 8682 | -- operands to get the ranges (and to properly process the subtree |
20cf157b | 8683 | -- that lies below us). |
3cce7f32 | 8684 | |
0df9d43f | 8685 | Minimize_Eliminate_Overflows |
0326b4d4 | 8686 | (Right_Opnd (N), Rlo, Rhi, Top_Level => False); |
3cce7f32 | 8687 | |
0326b4d4 | 8688 | if Binary then |
0df9d43f | 8689 | Minimize_Eliminate_Overflows |
0326b4d4 | 8690 | (Left_Opnd (N), Llo, Lhi, Top_Level => False); |
3cce7f32 | 8691 | end if; |
8692 | ||
f32c377d | 8693 | -- Record if we have Long_Long_Integer operands |
8694 | ||
8695 | Long_Long_Integer_Operands := | |
8696 | Etype (Right_Opnd (N)) = LLIB | |
8697 | or else (Binary and then Etype (Left_Opnd (N)) = LLIB); | |
8698 | ||
8699 | -- If either operand is a bignum, then result will be a bignum and we | |
8700 | -- don't need to do any range analysis. As previously discussed we could | |
8701 | -- do range analysis in such cases, but it could mean working with giant | |
8702 | -- numbers at compile time for very little gain (the number of cases | |
21a55437 | 8703 | -- in which we could slip back from bignum mode is small). |
3cce7f32 | 8704 | |
8705 | if Rlo = No_Uint or else (Binary and then Llo = No_Uint) then | |
8706 | Lo := No_Uint; | |
8707 | Hi := No_Uint; | |
61016a7a | 8708 | Bignum_Operands := True; |
3cce7f32 | 8709 | |
8710 | -- Otherwise compute result range | |
8711 | ||
8712 | else | |
61016a7a | 8713 | Bignum_Operands := False; |
8714 | ||
3cce7f32 | 8715 | case Nkind (N) is |
8716 | ||
8717 | -- Absolute value | |
8718 | ||
8719 | when N_Op_Abs => | |
8720 | Lo := Uint_0; | |
de922300 | 8721 | Hi := UI_Max (abs Rlo, abs Rhi); |
3cce7f32 | 8722 | |
8723 | -- Addition | |
8724 | ||
8725 | when N_Op_Add => | |
8726 | Lo := Llo + Rlo; | |
8727 | Hi := Lhi + Rhi; | |
8728 | ||
8729 | -- Division | |
8730 | ||
8731 | when N_Op_Divide => | |
2fe22c69 | 8732 | |
5f4275e1 | 8733 | -- If the right operand can only be zero, set 0..0 |
2fe22c69 | 8734 | |
5f4275e1 | 8735 | if Rlo = 0 and then Rhi = 0 then |
8736 | Lo := Uint_0; | |
8737 | Hi := Uint_0; | |
2fe22c69 | 8738 | |
5f4275e1 | 8739 | -- Possible bounds of division must come from dividing end |
8740 | -- values of the input ranges (four possibilities), provided | |
8741 | -- zero is not included in the possible values of the right | |
8742 | -- operand. | |
8743 | ||
8744 | -- Otherwise, we just consider two intervals of values for | |
8745 | -- the right operand: the interval of negative values (up to | |
8746 | -- -1) and the interval of positive values (starting at 1). | |
8747 | -- Since division by 1 is the identity, and division by -1 | |
8748 | -- is negation, we get all possible bounds of division in that | |
8749 | -- case by considering: | |
8750 | -- - all values from the division of end values of input | |
8751 | -- ranges; | |
8752 | -- - the end values of the left operand; | |
8753 | -- - the negation of the end values of the left operand. | |
2fe22c69 | 8754 | |
5f4275e1 | 8755 | else |
8756 | declare | |
8757 | Mrk : constant Uintp.Save_Mark := Mark; | |
8758 | -- Mark so we can release the RR and Ev values | |
2fe22c69 | 8759 | |
5f4275e1 | 8760 | Ev1 : Uint; |
8761 | Ev2 : Uint; | |
8762 | Ev3 : Uint; | |
8763 | Ev4 : Uint; | |
2fe22c69 | 8764 | |
5f4275e1 | 8765 | begin |
8766 | -- Discard extreme values of zero for the divisor, since | |
8767 | -- they will simply result in an exception in any case. | |
2fe22c69 | 8768 | |
5f4275e1 | 8769 | if Rlo = 0 then |
8770 | Rlo := Uint_1; | |
8771 | elsif Rhi = 0 then | |
8772 | Rhi := -Uint_1; | |
2fe22c69 | 8773 | end if; |
2fe22c69 | 8774 | |
5f4275e1 | 8775 | -- Compute possible bounds coming from dividing end |
8776 | -- values of the input ranges. | |
2fe22c69 | 8777 | |
5f4275e1 | 8778 | Ev1 := Llo / Rlo; |
8779 | Ev2 := Llo / Rhi; | |
8780 | Ev3 := Lhi / Rlo; | |
8781 | Ev4 := Lhi / Rhi; | |
2fe22c69 | 8782 | |
5f4275e1 | 8783 | Lo := UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4)); |
8784 | Hi := UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4)); | |
2fe22c69 | 8785 | |
5f4275e1 | 8786 | -- If the right operand can be both negative or positive, |
8787 | -- include the end values of the left operand in the | |
8788 | -- extreme values, as well as their negation. | |
2fe22c69 | 8789 | |
5f4275e1 | 8790 | if Rlo < 0 and then Rhi > 0 then |
8791 | Ev1 := Llo; | |
8792 | Ev2 := -Llo; | |
8793 | Ev3 := Lhi; | |
8794 | Ev4 := -Lhi; | |
2fe22c69 | 8795 | |
5f4275e1 | 8796 | Min (Lo, |
8797 | UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4))); | |
8798 | Max (Hi, | |
8799 | UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4))); | |
2fe22c69 | 8800 | end if; |
2fe22c69 | 8801 | |
5f4275e1 | 8802 | -- Release the RR and Ev values |
2fe22c69 | 8803 | |
5f4275e1 | 8804 | Release_And_Save (Mrk, Lo, Hi); |
8805 | end; | |
8806 | end if; | |
3cce7f32 | 8807 | |
8808 | -- Exponentiation | |
8809 | ||
8810 | when N_Op_Expon => | |
de922300 | 8811 | |
8812 | -- Discard negative values for the exponent, since they will | |
8813 | -- simply result in an exception in any case. | |
8814 | ||
8815 | if Rhi < 0 then | |
8816 | Rhi := Uint_0; | |
8817 | elsif Rlo < 0 then | |
8818 | Rlo := Uint_0; | |
8819 | end if; | |
8820 | ||
8821 | -- Estimate number of bits in result before we go computing | |
8822 | -- giant useless bounds. Basically the number of bits in the | |
8823 | -- result is the number of bits in the base multiplied by the | |
8824 | -- value of the exponent. If this is big enough that the result | |
8825 | -- definitely won't fit in Long_Long_Integer, switch to bignum | |
8826 | -- mode immediately, and avoid computing giant bounds. | |
8827 | ||
8828 | -- The comparison here is approximate, but conservative, it | |
8829 | -- only clicks on cases that are sure to exceed the bounds. | |
8830 | ||
8831 | if Num_Bits (UI_Max (abs Llo, abs Lhi)) * Rhi + 1 > 100 then | |
8832 | Lo := No_Uint; | |
8833 | Hi := No_Uint; | |
8834 | ||
8835 | -- If right operand is zero then result is 1 | |
8836 | ||
8837 | elsif Rhi = 0 then | |
8838 | Lo := Uint_1; | |
8839 | Hi := Uint_1; | |
8840 | ||
8841 | else | |
8842 | -- High bound comes either from exponentiation of largest | |
5f4275e1 | 8843 | -- positive value to largest exponent value, or from |
8844 | -- the exponentiation of most negative value to an | |
8845 | -- even exponent. | |
de922300 | 8846 | |
8847 | declare | |
8848 | Hi1, Hi2 : Uint; | |
8849 | ||
8850 | begin | |
5f4275e1 | 8851 | if Lhi > 0 then |
de922300 | 8852 | Hi1 := Lhi ** Rhi; |
8853 | else | |
8854 | Hi1 := Uint_0; | |
8855 | end if; | |
8856 | ||
8857 | if Llo < 0 then | |
8858 | if Rhi mod 2 = 0 then | |
de922300 | 8859 | Hi2 := Llo ** Rhi; |
5f4275e1 | 8860 | else |
8861 | Hi2 := Llo ** (Rhi - 1); | |
de922300 | 8862 | end if; |
8863 | else | |
8864 | Hi2 := Uint_0; | |
8865 | end if; | |
8866 | ||
8867 | Hi := UI_Max (Hi1, Hi2); | |
8868 | end; | |
8869 | ||
8870 | -- Result can only be negative if base can be negative | |
8871 | ||
8872 | if Llo < 0 then | |
21a55437 | 8873 | if Rhi mod 2 = 0 then |
de922300 | 8874 | Lo := Llo ** (Rhi - 1); |
8875 | else | |
8876 | Lo := Llo ** Rhi; | |
8877 | end if; | |
8878 | ||
21a55437 | 8879 | -- Otherwise low bound is minimum ** minimum |
de922300 | 8880 | |
8881 | else | |
8882 | Lo := Llo ** Rlo; | |
8883 | end if; | |
8884 | end if; | |
3cce7f32 | 8885 | |
8886 | -- Negation | |
8887 | ||
8888 | when N_Op_Minus => | |
8889 | Lo := -Rhi; | |
8890 | Hi := -Rlo; | |
8891 | ||
8892 | -- Mod | |
8893 | ||
8894 | when N_Op_Mod => | |
2fe22c69 | 8895 | declare |
5f4275e1 | 8896 | Maxabs : constant Uint := UI_Max (abs Rlo, abs Rhi) - 1; |
2fe22c69 | 8897 | -- This is the maximum absolute value of the result |
8898 | ||
8899 | begin | |
8900 | Lo := Uint_0; | |
8901 | Hi := Uint_0; | |
8902 | ||
8903 | -- The result depends only on the sign and magnitude of | |
8904 | -- the right operand, it does not depend on the sign or | |
8905 | -- magnitude of the left operand. | |
8906 | ||
8907 | if Rlo < 0 then | |
8908 | Lo := -Maxabs; | |
8909 | end if; | |
8910 | ||
8911 | if Rhi > 0 then | |
8912 | Hi := Maxabs; | |
8913 | end if; | |
8914 | end; | |
3cce7f32 | 8915 | |
8916 | -- Multiplication | |
8917 | ||
8918 | when N_Op_Multiply => | |
49b3a812 | 8919 | |
8920 | -- Possible bounds of multiplication must come from multiplying | |
8921 | -- end values of the input ranges (four possibilities). | |
8922 | ||
8923 | declare | |
8924 | Mrk : constant Uintp.Save_Mark := Mark; | |
8925 | -- Mark so we can release the Ev values | |
8926 | ||
8927 | Ev1 : constant Uint := Llo * Rlo; | |
8928 | Ev2 : constant Uint := Llo * Rhi; | |
8929 | Ev3 : constant Uint := Lhi * Rlo; | |
8930 | Ev4 : constant Uint := Lhi * Rhi; | |
8931 | ||
8932 | begin | |
8933 | Lo := UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4)); | |
8934 | Hi := UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4)); | |
8935 | ||
8936 | -- Release the Ev values | |
8937 | ||
8938 | Release_And_Save (Mrk, Lo, Hi); | |
8939 | end; | |
3cce7f32 | 8940 | |
8941 | -- Plus operator (affirmation) | |
8942 | ||
8943 | when N_Op_Plus => | |
8944 | Lo := Rlo; | |
8945 | Hi := Rhi; | |
8946 | ||
8947 | -- Remainder | |
8948 | ||
8949 | when N_Op_Rem => | |
2fe22c69 | 8950 | declare |
5f4275e1 | 8951 | Maxabs : constant Uint := UI_Max (abs Rlo, abs Rhi) - 1; |
2fe22c69 | 8952 | -- This is the maximum absolute value of the result. Note |
5f4275e1 | 8953 | -- that the result range does not depend on the sign of the |
8954 | -- right operand. | |
2fe22c69 | 8955 | |
8956 | begin | |
8957 | Lo := Uint_0; | |
8958 | Hi := Uint_0; | |
8959 | ||
8960 | -- Case of left operand negative, which results in a range | |
8961 | -- of -Maxabs .. 0 for those negative values. If there are | |
8962 | -- no negative values then Lo value of result is always 0. | |
8963 | ||
8964 | if Llo < 0 then | |
8965 | Lo := -Maxabs; | |
8966 | end if; | |
8967 | ||
8968 | -- Case of left operand positive | |
8969 | ||
8970 | if Lhi > 0 then | |
8971 | Hi := Maxabs; | |
8972 | end if; | |
8973 | end; | |
3cce7f32 | 8974 | |
8975 | -- Subtract | |
8976 | ||
8977 | when N_Op_Subtract => | |
8978 | Lo := Llo - Rhi; | |
8979 | Hi := Lhi - Rlo; | |
8980 | ||
8981 | -- Nothing else should be possible | |
8982 | ||
8983 | when others => | |
8984 | raise Program_Error; | |
3cce7f32 | 8985 | end case; |
8986 | end if; | |
8987 | ||
4fb5f0a0 | 8988 | -- Here for the case where we have not rewritten anything (no bignum |
21a55437 | 8989 | -- operands or long long integer operands), and we know the result. |
8990 | -- If we know we are in the result range, and we do not have Bignum | |
8991 | -- operands or Long_Long_Integer operands, we can just reexpand with | |
8992 | -- overflow checks turned off (since we know we cannot have overflow). | |
8993 | -- As always the reexpansion is required to complete expansion of the | |
8994 | -- operator, but we do not need to reanalyze, and we prevent recursion | |
8995 | -- by suppressing the check. | |
f32c377d | 8996 | |
8997 | if not (Bignum_Operands or Long_Long_Integer_Operands) | |
8998 | and then In_Result_Range | |
8999 | then | |
9000 | Set_Do_Overflow_Check (N, False); | |
0df9d43f | 9001 | Reexpand (Suppress => True); |
f32c377d | 9002 | return; |
9003 | ||
9004 | -- Here we know that we are not in the result range, and in the general | |
21a55437 | 9005 | -- case we will move into either the Bignum or Long_Long_Integer domain |
9006 | -- to compute the result. However, there is one exception. If we are | |
9007 | -- at the top level, and we do not have Bignum or Long_Long_Integer | |
9008 | -- operands, we will have to immediately convert the result back to | |
9009 | -- the result type, so there is no point in Bignum/Long_Long_Integer | |
9010 | -- fiddling. | |
f32c377d | 9011 | |
9012 | elsif Top_Level | |
9013 | and then not (Bignum_Operands or Long_Long_Integer_Operands) | |
b6a8f264 | 9014 | |
9015 | -- One further refinement. If we are at the top level, but our parent | |
9016 | -- is a type conversion, then go into bignum or long long integer node | |
9017 | -- since the result will be converted to that type directly without | |
9018 | -- going through the result type, and we may avoid an overflow. This | |
9019 | -- is the case for example of Long_Long_Integer (A ** 4), where A is | |
9020 | -- of type Integer, and the result A ** 4 fits in Long_Long_Integer | |
9021 | -- but does not fit in Integer. | |
9022 | ||
9023 | and then Nkind (Parent (N)) /= N_Type_Conversion | |
f32c377d | 9024 | then |
0df9d43f | 9025 | -- Here keep original types, but we need to complete analysis |
f32c377d | 9026 | |
9027 | -- One subtlety. We can't just go ahead and do an analyze operation | |
21a55437 | 9028 | -- here because it will cause recursion into the whole MINIMIZED/ |
9029 | -- ELIMINATED overflow processing which is not what we want. Here | |
f32c377d | 9030 | -- we are at the top level, and we need a check against the result |
39a0c1d3 | 9031 | -- mode (i.e. we want to use STRICT mode). So do exactly that. |
4fb5f0a0 | 9032 | -- Also, we have not modified the node, so this is a case where |
9033 | -- we need to reexpand, but not reanalyze. | |
f32c377d | 9034 | |
0df9d43f | 9035 | Reexpand; |
f32c377d | 9036 | return; |
9037 | ||
9038 | -- Cases where we do the operation in Bignum mode. This happens either | |
3cce7f32 | 9039 | -- because one of our operands is in Bignum mode already, or because |
de922300 | 9040 | -- the computed bounds are outside the bounds of Long_Long_Integer, |
9041 | -- which in some cases can be indicated by Hi and Lo being No_Uint. | |
3cce7f32 | 9042 | |
9043 | -- Note: we could do better here and in some cases switch back from | |
9044 | -- Bignum mode to normal mode, e.g. big mod 2 must be in the range | |
9045 | -- 0 .. 1, but the cases are rare and it is not worth the effort. | |
9046 | -- Failing to do this switching back is only an efficiency issue. | |
9047 | ||
f32c377d | 9048 | elsif Lo = No_Uint or else Lo < LLLo or else Hi > LLHi then |
3cce7f32 | 9049 | |
61016a7a | 9050 | -- OK, we are definitely outside the range of Long_Long_Integer. The |
f32c377d | 9051 | -- question is whether to move to Bignum mode, or stay in the domain |
61016a7a | 9052 | -- of Long_Long_Integer, signalling that an overflow check is needed. |
9053 | ||
9054 | -- Obviously in MINIMIZED mode we stay with LLI, since we are not in | |
9055 | -- the Bignum business. In ELIMINATED mode, we will normally move | |
9056 | -- into Bignum mode, but there is an exception if neither of our | |
9057 | -- operands is Bignum now, and we are at the top level (Top_Level | |
9058 | -- set True). In this case, there is no point in moving into Bignum | |
9059 | -- mode to prevent overflow if the caller will immediately convert | |
9060 | -- the Bignum value back to LLI with an overflow check. It's more | |
0df9d43f | 9061 | -- efficient to stay in LLI mode with an overflow check (if needed) |
61016a7a | 9062 | |
9063 | if Check_Mode = Minimized | |
9064 | or else (Top_Level and not Bignum_Operands) | |
9065 | then | |
0df9d43f | 9066 | if Do_Overflow_Check (N) then |
9067 | Enable_Overflow_Check (N); | |
9068 | end if; | |
3cce7f32 | 9069 | |
0df9d43f | 9070 | -- The result now has to be in Long_Long_Integer mode, so adjust |
9071 | -- the possible range to reflect this. Note these calls also | |
9072 | -- change No_Uint values from the top level case to LLI bounds. | |
61016a7a | 9073 | |
9074 | Max (Lo, LLLo); | |
9075 | Min (Hi, LLHi); | |
9076 | ||
9077 | -- Otherwise we are in ELIMINATED mode and we switch to Bignum mode | |
3cce7f32 | 9078 | |
9079 | else | |
9080 | pragma Assert (Check_Mode = Eliminated); | |
9081 | ||
9082 | declare | |
9083 | Fent : Entity_Id; | |
9084 | Args : List_Id; | |
9085 | ||
9086 | begin | |
9087 | case Nkind (N) is | |
99378362 | 9088 | when N_Op_Abs => |
3cce7f32 | 9089 | Fent := RTE (RE_Big_Abs); |
9090 | ||
99378362 | 9091 | when N_Op_Add => |
3cce7f32 | 9092 | Fent := RTE (RE_Big_Add); |
9093 | ||
99378362 | 9094 | when N_Op_Divide => |
3cce7f32 | 9095 | Fent := RTE (RE_Big_Div); |
9096 | ||
99378362 | 9097 | when N_Op_Expon => |
3cce7f32 | 9098 | Fent := RTE (RE_Big_Exp); |
9099 | ||
99378362 | 9100 | when N_Op_Minus => |
3cce7f32 | 9101 | Fent := RTE (RE_Big_Neg); |
9102 | ||
99378362 | 9103 | when N_Op_Mod => |
3cce7f32 | 9104 | Fent := RTE (RE_Big_Mod); |
9105 | ||
9106 | when N_Op_Multiply => | |
9107 | Fent := RTE (RE_Big_Mul); | |
9108 | ||
99378362 | 9109 | when N_Op_Rem => |
3cce7f32 | 9110 | Fent := RTE (RE_Big_Rem); |
9111 | ||
9112 | when N_Op_Subtract => | |
9113 | Fent := RTE (RE_Big_Sub); | |
9114 | ||
9115 | -- Anything else is an internal error, this includes the | |
9116 | -- N_Op_Plus case, since how can plus cause the result | |
9117 | -- to be out of range if the operand is in range? | |
9118 | ||
9119 | when others => | |
9120 | raise Program_Error; | |
9121 | end case; | |
9122 | ||
9123 | -- Construct argument list for Bignum call, converting our | |
9124 | -- operands to Bignum form if they are not already there. | |
9125 | ||
9126 | Args := New_List; | |
9127 | ||
9128 | if Binary then | |
9129 | Append_To (Args, Convert_To_Bignum (Left_Opnd (N))); | |
9130 | end if; | |
9131 | ||
9132 | Append_To (Args, Convert_To_Bignum (Right_Opnd (N))); | |
9133 | ||
9134 | -- Now rewrite the arithmetic operator with a call to the | |
9135 | -- corresponding bignum function. | |
9136 | ||
9137 | Rewrite (N, | |
9138 | Make_Function_Call (Loc, | |
9139 | Name => New_Occurrence_Of (Fent, Loc), | |
9140 | Parameter_Associations => Args)); | |
0df9d43f | 9141 | Reanalyze (RTE (RE_Bignum), Suppress => True); |
61016a7a | 9142 | |
9143 | -- Indicate result is Bignum mode | |
9144 | ||
9145 | Lo := No_Uint; | |
9146 | Hi := No_Uint; | |
de922300 | 9147 | return; |
3cce7f32 | 9148 | end; |
9149 | end if; | |
9150 | ||
9151 | -- Otherwise we are in range of Long_Long_Integer, so no overflow | |
de922300 | 9152 | -- check is required, at least not yet. |
3cce7f32 | 9153 | |
9154 | else | |
de922300 | 9155 | Set_Do_Overflow_Check (N, False); |
9156 | end if; | |
3cce7f32 | 9157 | |
f32c377d | 9158 | -- Here we are not in Bignum territory, but we may have long long |
9159 | -- integer operands that need special handling. First a special check: | |
9160 | -- If an exponentiation operator exponent is of type Long_Long_Integer, | |
9161 | -- it means we converted it to prevent overflow, but exponentiation | |
9162 | -- requires a Natural right operand, so convert it back to Natural. | |
9163 | -- This conversion may raise an exception which is fine. | |
0326b4d4 | 9164 | |
f32c377d | 9165 | if Nkind (N) = N_Op_Expon and then Etype (Right_Opnd (N)) = LLIB then |
9166 | Convert_To_And_Rewrite (Standard_Natural, Right_Opnd (N)); | |
0326b4d4 | 9167 | end if; |
9168 | ||
de922300 | 9169 | -- Here we will do the operation in Long_Long_Integer. We do this even |
9170 | -- if we know an overflow check is required, better to do this in long | |
39a0c1d3 | 9171 | -- long integer mode, since we are less likely to overflow. |
3cce7f32 | 9172 | |
de922300 | 9173 | -- Convert right or only operand to Long_Long_Integer, except that |
9174 | -- we do not touch the exponentiation right operand. | |
3cce7f32 | 9175 | |
de922300 | 9176 | if Nkind (N) /= N_Op_Expon then |
9177 | Convert_To_And_Rewrite (LLIB, Right_Opnd (N)); | |
9178 | end if; | |
3cce7f32 | 9179 | |
de922300 | 9180 | -- Convert left operand to Long_Long_Integer for binary case |
49b3a812 | 9181 | |
de922300 | 9182 | if Binary then |
9183 | Convert_To_And_Rewrite (LLIB, Left_Opnd (N)); | |
9184 | end if; | |
9185 | ||
9186 | -- Reset node to unanalyzed | |
9187 | ||
9188 | Set_Analyzed (N, False); | |
9189 | Set_Etype (N, Empty); | |
9190 | Set_Entity (N, Empty); | |
9191 | ||
2fe22c69 | 9192 | -- Now analyze this new node. This reanalysis will complete processing |
9193 | -- for the node. In particular we will complete the expansion of an | |
9194 | -- exponentiation operator (e.g. changing A ** 2 to A * A), and also | |
9195 | -- we will complete any division checks (since we have not changed the | |
9196 | -- setting of the Do_Division_Check flag). | |
3cce7f32 | 9197 | |
0df9d43f | 9198 | -- We do this reanalysis in STRICT mode to avoid recursion into the |
39a0c1d3 | 9199 | -- MINIMIZED/ELIMINATED handling, since we are now done with that. |
3cce7f32 | 9200 | |
0df9d43f | 9201 | declare |
db415383 | 9202 | SG : constant Overflow_Mode_Type := |
9203 | Scope_Suppress.Overflow_Mode_General; | |
9204 | SA : constant Overflow_Mode_Type := | |
9205 | Scope_Suppress.Overflow_Mode_Assertions; | |
de922300 | 9206 | |
0df9d43f | 9207 | begin |
db415383 | 9208 | Scope_Suppress.Overflow_Mode_General := Strict; |
9209 | Scope_Suppress.Overflow_Mode_Assertions := Strict; | |
de922300 | 9210 | |
0df9d43f | 9211 | if not Do_Overflow_Check (N) then |
9212 | Reanalyze (LLIB, Suppress => True); | |
9213 | else | |
9214 | Reanalyze (LLIB); | |
9215 | end if; | |
9216 | ||
db415383 | 9217 | Scope_Suppress.Overflow_Mode_General := SG; |
9218 | Scope_Suppress.Overflow_Mode_Assertions := SA; | |
0df9d43f | 9219 | end; |
9220 | end Minimize_Eliminate_Overflows; | |
3cce7f32 | 9221 | |
9222 | ------------------------- | |
9223 | -- Overflow_Check_Mode -- | |
9224 | ------------------------- | |
9225 | ||
db415383 | 9226 | function Overflow_Check_Mode return Overflow_Mode_Type is |
ee6ba406 | 9227 | begin |
724d2bd8 | 9228 | if In_Assertion_Expr = 0 then |
db415383 | 9229 | return Scope_Suppress.Overflow_Mode_General; |
9dfe12ae | 9230 | else |
db415383 | 9231 | return Scope_Suppress.Overflow_Mode_Assertions; |
9dfe12ae | 9232 | end if; |
3cce7f32 | 9233 | end Overflow_Check_Mode; |
9234 | ||
9235 | -------------------------------- | |
9236 | -- Overflow_Checks_Suppressed -- | |
9237 | -------------------------------- | |
9238 | ||
9239 | function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is | |
9240 | begin | |
0df9d43f | 9241 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
9242 | return Is_Check_Suppressed (E, Overflow_Check); | |
9243 | else | |
9244 | return Scope_Suppress.Suppress (Overflow_Check); | |
9245 | end if; | |
ee6ba406 | 9246 | end Overflow_Checks_Suppressed; |
fc75802a | 9247 | |
37baba83 | 9248 | --------------------------------- |
9249 | -- Predicate_Checks_Suppressed -- | |
9250 | --------------------------------- | |
9251 | ||
9252 | function Predicate_Checks_Suppressed (E : Entity_Id) return Boolean is | |
9253 | begin | |
9254 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
9255 | return Is_Check_Suppressed (E, Predicate_Check); | |
9256 | else | |
9257 | return Scope_Suppress.Suppress (Predicate_Check); | |
9258 | end if; | |
9259 | end Predicate_Checks_Suppressed; | |
9260 | ||
ee6ba406 | 9261 | ----------------------------- |
9262 | -- Range_Checks_Suppressed -- | |
9263 | ----------------------------- | |
9264 | ||
9265 | function Range_Checks_Suppressed (E : Entity_Id) return Boolean is | |
9266 | begin | |
9dfe12ae | 9267 | if Present (E) then |
ce4d14c4 | 9268 | if Kill_Range_Checks (E) then |
9dfe12ae | 9269 | return True; |
5f46de53 | 9270 | |
9dfe12ae | 9271 | elsif Checks_May_Be_Suppressed (E) then |
9272 | return Is_Check_Suppressed (E, Range_Check); | |
9273 | end if; | |
9274 | end if; | |
ee6ba406 | 9275 | |
fafc6b97 | 9276 | return Scope_Suppress.Suppress (Range_Check); |
ee6ba406 | 9277 | end Range_Checks_Suppressed; |
9278 | ||
0577b0b1 | 9279 | ----------------------------------------- |
9280 | -- Range_Or_Validity_Checks_Suppressed -- | |
9281 | ----------------------------------------- | |
9282 | ||
9283 | -- Note: the coding would be simpler here if we simply made appropriate | |
9284 | -- calls to Range/Validity_Checks_Suppressed, but that would result in | |
9285 | -- duplicated checks which we prefer to avoid. | |
9286 | ||
9287 | function Range_Or_Validity_Checks_Suppressed | |
9288 | (Expr : Node_Id) return Boolean | |
9289 | is | |
9290 | begin | |
9291 | -- Immediate return if scope checks suppressed for either check | |
9292 | ||
fafc6b97 | 9293 | if Scope_Suppress.Suppress (Range_Check) |
9294 | or | |
9295 | Scope_Suppress.Suppress (Validity_Check) | |
9296 | then | |
0577b0b1 | 9297 | return True; |
9298 | end if; | |
9299 | ||
9300 | -- If no expression, that's odd, decide that checks are suppressed, | |
9301 | -- since we don't want anyone trying to do checks in this case, which | |
9302 | -- is most likely the result of some other error. | |
9303 | ||
9304 | if No (Expr) then | |
9305 | return True; | |
9306 | end if; | |
9307 | ||
9308 | -- Expression is present, so perform suppress checks on type | |
9309 | ||
9310 | declare | |
9311 | Typ : constant Entity_Id := Etype (Expr); | |
9312 | begin | |
ce4d14c4 | 9313 | if Checks_May_Be_Suppressed (Typ) |
0577b0b1 | 9314 | and then (Is_Check_Suppressed (Typ, Range_Check) |
9315 | or else | |
9316 | Is_Check_Suppressed (Typ, Validity_Check)) | |
9317 | then | |
9318 | return True; | |
9319 | end if; | |
9320 | end; | |
9321 | ||
9322 | -- If expression is an entity name, perform checks on this entity | |
9323 | ||
9324 | if Is_Entity_Name (Expr) then | |
9325 | declare | |
9326 | Ent : constant Entity_Id := Entity (Expr); | |
9327 | begin | |
9328 | if Checks_May_Be_Suppressed (Ent) then | |
9329 | return Is_Check_Suppressed (Ent, Range_Check) | |
9330 | or else Is_Check_Suppressed (Ent, Validity_Check); | |
9331 | end if; | |
9332 | end; | |
9333 | end if; | |
9334 | ||
9335 | -- If we fall through, no checks suppressed | |
9336 | ||
9337 | return False; | |
9338 | end Range_Or_Validity_Checks_Suppressed; | |
9339 | ||
226494a3 | 9340 | ------------------- |
9341 | -- Remove_Checks -- | |
9342 | ------------------- | |
9343 | ||
9344 | procedure Remove_Checks (Expr : Node_Id) is | |
226494a3 | 9345 | function Process (N : Node_Id) return Traverse_Result; |
9346 | -- Process a single node during the traversal | |
9347 | ||
8f6e4fd5 | 9348 | procedure Traverse is new Traverse_Proc (Process); |
9349 | -- The traversal procedure itself | |
226494a3 | 9350 | |
9351 | ------------- | |
9352 | -- Process -- | |
9353 | ------------- | |
9354 | ||
9355 | function Process (N : Node_Id) return Traverse_Result is | |
9356 | begin | |
9357 | if Nkind (N) not in N_Subexpr then | |
9358 | return Skip; | |
9359 | end if; | |
9360 | ||
9361 | Set_Do_Range_Check (N, False); | |
9362 | ||
9363 | case Nkind (N) is | |
9364 | when N_And_Then => | |
8f6e4fd5 | 9365 | Traverse (Left_Opnd (N)); |
226494a3 | 9366 | return Skip; |
9367 | ||
9368 | when N_Attribute_Reference => | |
226494a3 | 9369 | Set_Do_Overflow_Check (N, False); |
9370 | ||
226494a3 | 9371 | when N_Function_Call => |
9372 | Set_Do_Tag_Check (N, False); | |
9373 | ||
226494a3 | 9374 | when N_Op => |
9375 | Set_Do_Overflow_Check (N, False); | |
9376 | ||
9377 | case Nkind (N) is | |
9378 | when N_Op_Divide => | |
9379 | Set_Do_Division_Check (N, False); | |
9380 | ||
9381 | when N_Op_And => | |
9382 | Set_Do_Length_Check (N, False); | |
9383 | ||
9384 | when N_Op_Mod => | |
9385 | Set_Do_Division_Check (N, False); | |
9386 | ||
9387 | when N_Op_Or => | |
9388 | Set_Do_Length_Check (N, False); | |
9389 | ||
9390 | when N_Op_Rem => | |
9391 | Set_Do_Division_Check (N, False); | |
9392 | ||
9393 | when N_Op_Xor => | |
9394 | Set_Do_Length_Check (N, False); | |
9395 | ||
9396 | when others => | |
9397 | null; | |
9398 | end case; | |
9399 | ||
9400 | when N_Or_Else => | |
8f6e4fd5 | 9401 | Traverse (Left_Opnd (N)); |
226494a3 | 9402 | return Skip; |
9403 | ||
9404 | when N_Selected_Component => | |
226494a3 | 9405 | Set_Do_Discriminant_Check (N, False); |
9406 | ||
226494a3 | 9407 | when N_Type_Conversion => |
9dfe12ae | 9408 | Set_Do_Length_Check (N, False); |
9409 | Set_Do_Tag_Check (N, False); | |
226494a3 | 9410 | Set_Do_Overflow_Check (N, False); |
226494a3 | 9411 | |
9412 | when others => | |
9413 | null; | |
9414 | end case; | |
9415 | ||
9416 | return OK; | |
9417 | end Process; | |
9418 | ||
9419 | -- Start of processing for Remove_Checks | |
9420 | ||
9421 | begin | |
8f6e4fd5 | 9422 | Traverse (Expr); |
226494a3 | 9423 | end Remove_Checks; |
9424 | ||
ee6ba406 | 9425 | ---------------------------- |
9426 | -- Selected_Length_Checks -- | |
9427 | ---------------------------- | |
9428 | ||
9429 | function Selected_Length_Checks | |
9430 | (Ck_Node : Node_Id; | |
9431 | Target_Typ : Entity_Id; | |
9432 | Source_Typ : Entity_Id; | |
314a23b6 | 9433 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 9434 | is |
9435 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
9436 | S_Typ : Entity_Id; | |
9437 | T_Typ : Entity_Id; | |
9438 | Expr_Actual : Node_Id; | |
9439 | Exptyp : Entity_Id; | |
9440 | Cond : Node_Id := Empty; | |
9441 | Do_Access : Boolean := False; | |
9442 | Wnode : Node_Id := Warn_Node; | |
9443 | Ret_Result : Check_Result := (Empty, Empty); | |
9444 | Num_Checks : Natural := 0; | |
9445 | ||
9446 | procedure Add_Check (N : Node_Id); | |
9447 | -- Adds the action given to Ret_Result if N is non-Empty | |
9448 | ||
9449 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id; | |
9450 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id; | |
314a23b6 | 9451 | -- Comments required ??? |
ee6ba406 | 9452 | |
9453 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean; | |
9454 | -- True for equal literals and for nodes that denote the same constant | |
5f260d20 | 9455 | -- entity, even if its value is not a static constant. This includes the |
9dfe12ae | 9456 | -- case of a discriminal reference within an init proc. Removes some |
5f260d20 | 9457 | -- obviously superfluous checks. |
ee6ba406 | 9458 | |
9459 | function Length_E_Cond | |
9460 | (Exptyp : Entity_Id; | |
9461 | Typ : Entity_Id; | |
314a23b6 | 9462 | Indx : Nat) return Node_Id; |
ee6ba406 | 9463 | -- Returns expression to compute: |
9464 | -- Typ'Length /= Exptyp'Length | |
9465 | ||
9466 | function Length_N_Cond | |
9467 | (Expr : Node_Id; | |
9468 | Typ : Entity_Id; | |
314a23b6 | 9469 | Indx : Nat) return Node_Id; |
ee6ba406 | 9470 | -- Returns expression to compute: |
9471 | -- Typ'Length /= Expr'Length | |
9472 | ||
9473 | --------------- | |
9474 | -- Add_Check -- | |
9475 | --------------- | |
9476 | ||
9477 | procedure Add_Check (N : Node_Id) is | |
9478 | begin | |
9479 | if Present (N) then | |
9480 | ||
20cf157b | 9481 | -- For now, ignore attempt to place more than two checks ??? |
9482 | -- This is really worrisome, are we really discarding checks ??? | |
ee6ba406 | 9483 | |
9484 | if Num_Checks = 2 then | |
9485 | return; | |
9486 | end if; | |
9487 | ||
9488 | pragma Assert (Num_Checks <= 1); | |
9489 | Num_Checks := Num_Checks + 1; | |
9490 | Ret_Result (Num_Checks) := N; | |
9491 | end if; | |
9492 | end Add_Check; | |
9493 | ||
9494 | ------------------ | |
9495 | -- Get_E_Length -- | |
9496 | ------------------ | |
9497 | ||
9498 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is | |
00c403ee | 9499 | SE : constant Entity_Id := Scope (E); |
ee6ba406 | 9500 | N : Node_Id; |
9501 | E1 : Entity_Id := E; | |
ee6ba406 | 9502 | |
9503 | begin | |
9504 | if Ekind (Scope (E)) = E_Record_Type | |
9505 | and then Has_Discriminants (Scope (E)) | |
9506 | then | |
9507 | N := Build_Discriminal_Subtype_Of_Component (E); | |
9508 | ||
9509 | if Present (N) then | |
9510 | Insert_Action (Ck_Node, N); | |
9511 | E1 := Defining_Identifier (N); | |
9512 | end if; | |
9513 | end if; | |
9514 | ||
9515 | if Ekind (E1) = E_String_Literal_Subtype then | |
9516 | return | |
9517 | Make_Integer_Literal (Loc, | |
9518 | Intval => String_Literal_Length (E1)); | |
9519 | ||
00c403ee | 9520 | elsif SE /= Standard_Standard |
9521 | and then Ekind (Scope (SE)) = E_Protected_Type | |
9522 | and then Has_Discriminants (Scope (SE)) | |
9523 | and then Has_Completion (Scope (SE)) | |
ee6ba406 | 9524 | and then not Inside_Init_Proc |
9525 | then | |
ee6ba406 | 9526 | -- If the type whose length is needed is a private component |
9527 | -- constrained by a discriminant, we must expand the 'Length | |
9528 | -- attribute into an explicit computation, using the discriminal | |
9529 | -- of the current protected operation. This is because the actual | |
9530 | -- type of the prival is constructed after the protected opera- | |
9531 | -- tion has been fully expanded. | |
9532 | ||
9533 | declare | |
9534 | Indx_Type : Node_Id; | |
9535 | Lo : Node_Id; | |
9536 | Hi : Node_Id; | |
9537 | Do_Expand : Boolean := False; | |
9538 | ||
9539 | begin | |
9540 | Indx_Type := First_Index (E); | |
9541 | ||
9542 | for J in 1 .. Indx - 1 loop | |
9543 | Next_Index (Indx_Type); | |
9544 | end loop; | |
9545 | ||
2af58f67 | 9546 | Get_Index_Bounds (Indx_Type, Lo, Hi); |
ee6ba406 | 9547 | |
9548 | if Nkind (Lo) = N_Identifier | |
9549 | and then Ekind (Entity (Lo)) = E_In_Parameter | |
9550 | then | |
9551 | Lo := Get_Discriminal (E, Lo); | |
9552 | Do_Expand := True; | |
9553 | end if; | |
9554 | ||
9555 | if Nkind (Hi) = N_Identifier | |
9556 | and then Ekind (Entity (Hi)) = E_In_Parameter | |
9557 | then | |
9558 | Hi := Get_Discriminal (E, Hi); | |
9559 | Do_Expand := True; | |
9560 | end if; | |
9561 | ||
9562 | if Do_Expand then | |
9563 | if not Is_Entity_Name (Lo) then | |
9dfe12ae | 9564 | Lo := Duplicate_Subexpr_No_Checks (Lo); |
ee6ba406 | 9565 | end if; |
9566 | ||
9567 | if not Is_Entity_Name (Hi) then | |
9dfe12ae | 9568 | Lo := Duplicate_Subexpr_No_Checks (Hi); |
ee6ba406 | 9569 | end if; |
9570 | ||
9571 | N := | |
9572 | Make_Op_Add (Loc, | |
9573 | Left_Opnd => | |
9574 | Make_Op_Subtract (Loc, | |
9575 | Left_Opnd => Hi, | |
9576 | Right_Opnd => Lo), | |
9577 | ||
9578 | Right_Opnd => Make_Integer_Literal (Loc, 1)); | |
9579 | return N; | |
9580 | ||
9581 | else | |
9582 | N := | |
9583 | Make_Attribute_Reference (Loc, | |
9584 | Attribute_Name => Name_Length, | |
9585 | Prefix => | |
9586 | New_Occurrence_Of (E1, Loc)); | |
9587 | ||
9588 | if Indx > 1 then | |
9589 | Set_Expressions (N, New_List ( | |
9590 | Make_Integer_Literal (Loc, Indx))); | |
9591 | end if; | |
9592 | ||
9593 | return N; | |
9594 | end if; | |
9595 | end; | |
9596 | ||
9597 | else | |
9598 | N := | |
9599 | Make_Attribute_Reference (Loc, | |
9600 | Attribute_Name => Name_Length, | |
9601 | Prefix => | |
9602 | New_Occurrence_Of (E1, Loc)); | |
9603 | ||
9604 | if Indx > 1 then | |
9605 | Set_Expressions (N, New_List ( | |
9606 | Make_Integer_Literal (Loc, Indx))); | |
9607 | end if; | |
9608 | ||
9609 | return N; | |
ee6ba406 | 9610 | end if; |
9611 | end Get_E_Length; | |
9612 | ||
9613 | ------------------ | |
9614 | -- Get_N_Length -- | |
9615 | ------------------ | |
9616 | ||
9617 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is | |
9618 | begin | |
9619 | return | |
9620 | Make_Attribute_Reference (Loc, | |
9621 | Attribute_Name => Name_Length, | |
9622 | Prefix => | |
9dfe12ae | 9623 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 9624 | Expressions => New_List ( |
9625 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 9626 | end Get_N_Length; |
9627 | ||
9628 | ------------------- | |
9629 | -- Length_E_Cond -- | |
9630 | ------------------- | |
9631 | ||
9632 | function Length_E_Cond | |
9633 | (Exptyp : Entity_Id; | |
9634 | Typ : Entity_Id; | |
314a23b6 | 9635 | Indx : Nat) return Node_Id |
ee6ba406 | 9636 | is |
9637 | begin | |
9638 | return | |
9639 | Make_Op_Ne (Loc, | |
9640 | Left_Opnd => Get_E_Length (Typ, Indx), | |
9641 | Right_Opnd => Get_E_Length (Exptyp, Indx)); | |
ee6ba406 | 9642 | end Length_E_Cond; |
9643 | ||
9644 | ------------------- | |
9645 | -- Length_N_Cond -- | |
9646 | ------------------- | |
9647 | ||
9648 | function Length_N_Cond | |
9649 | (Expr : Node_Id; | |
9650 | Typ : Entity_Id; | |
314a23b6 | 9651 | Indx : Nat) return Node_Id |
ee6ba406 | 9652 | is |
9653 | begin | |
9654 | return | |
9655 | Make_Op_Ne (Loc, | |
9656 | Left_Opnd => Get_E_Length (Typ, Indx), | |
9657 | Right_Opnd => Get_N_Length (Expr, Indx)); | |
ee6ba406 | 9658 | end Length_N_Cond; |
9659 | ||
feff2f05 | 9660 | ----------------- |
9661 | -- Same_Bounds -- | |
9662 | ----------------- | |
9663 | ||
ee6ba406 | 9664 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is |
9665 | begin | |
9666 | return | |
9667 | (Nkind (L) = N_Integer_Literal | |
9668 | and then Nkind (R) = N_Integer_Literal | |
9669 | and then Intval (L) = Intval (R)) | |
9670 | ||
9671 | or else | |
9672 | (Is_Entity_Name (L) | |
9673 | and then Ekind (Entity (L)) = E_Constant | |
9674 | and then ((Is_Entity_Name (R) | |
9675 | and then Entity (L) = Entity (R)) | |
9676 | or else | |
9677 | (Nkind (R) = N_Type_Conversion | |
9678 | and then Is_Entity_Name (Expression (R)) | |
9679 | and then Entity (L) = Entity (Expression (R))))) | |
9680 | ||
9681 | or else | |
9682 | (Is_Entity_Name (R) | |
9683 | and then Ekind (Entity (R)) = E_Constant | |
9684 | and then Nkind (L) = N_Type_Conversion | |
9685 | and then Is_Entity_Name (Expression (L)) | |
5f260d20 | 9686 | and then Entity (R) = Entity (Expression (L))) |
9687 | ||
9688 | or else | |
9689 | (Is_Entity_Name (L) | |
9690 | and then Is_Entity_Name (R) | |
9691 | and then Entity (L) = Entity (R) | |
9692 | and then Ekind (Entity (L)) = E_In_Parameter | |
9693 | and then Inside_Init_Proc); | |
ee6ba406 | 9694 | end Same_Bounds; |
9695 | ||
9696 | -- Start of processing for Selected_Length_Checks | |
9697 | ||
9698 | begin | |
18cb6d78 | 9699 | -- Checks will be applied only when generating code |
f0d65dae | 9700 | |
18cb6d78 | 9701 | if not Expander_Active then |
ee6ba406 | 9702 | return Ret_Result; |
9703 | end if; | |
9704 | ||
9705 | if Target_Typ = Any_Type | |
9706 | or else Target_Typ = Any_Composite | |
9707 | or else Raises_Constraint_Error (Ck_Node) | |
9708 | then | |
9709 | return Ret_Result; | |
9710 | end if; | |
9711 | ||
9712 | if No (Wnode) then | |
9713 | Wnode := Ck_Node; | |
9714 | end if; | |
9715 | ||
9716 | T_Typ := Target_Typ; | |
9717 | ||
9718 | if No (Source_Typ) then | |
9719 | S_Typ := Etype (Ck_Node); | |
9720 | else | |
9721 | S_Typ := Source_Typ; | |
9722 | end if; | |
9723 | ||
9724 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
9725 | return Ret_Result; | |
9726 | end if; | |
9727 | ||
9728 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
9729 | S_Typ := Designated_Type (S_Typ); | |
9730 | T_Typ := Designated_Type (T_Typ); | |
9731 | Do_Access := True; | |
9732 | ||
2af58f67 | 9733 | -- A simple optimization for the null case |
ee6ba406 | 9734 | |
2af58f67 | 9735 | if Known_Null (Ck_Node) then |
ee6ba406 | 9736 | return Ret_Result; |
9737 | end if; | |
9738 | end if; | |
9739 | ||
9740 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
9741 | if Is_Constrained (T_Typ) then | |
9742 | ||
92f1631f | 9743 | -- The checking code to be generated will freeze the corresponding |
9744 | -- array type. However, we must freeze the type now, so that the | |
9745 | -- freeze node does not appear within the generated if expression, | |
9746 | -- but ahead of it. | |
ee6ba406 | 9747 | |
9748 | Freeze_Before (Ck_Node, T_Typ); | |
9749 | ||
9750 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
84d0d4a5 | 9751 | Exptyp := Get_Actual_Subtype (Ck_Node); |
ee6ba406 | 9752 | |
9753 | if Is_Access_Type (Exptyp) then | |
9754 | Exptyp := Designated_Type (Exptyp); | |
9755 | end if; | |
9756 | ||
9757 | -- String_Literal case. This needs to be handled specially be- | |
9758 | -- cause no index types are available for string literals. The | |
9759 | -- condition is simply: | |
9760 | ||
9761 | -- T_Typ'Length = string-literal-length | |
9762 | ||
9dfe12ae | 9763 | if Nkind (Expr_Actual) = N_String_Literal |
9764 | and then Ekind (Etype (Expr_Actual)) = E_String_Literal_Subtype | |
9765 | then | |
ee6ba406 | 9766 | Cond := |
9767 | Make_Op_Ne (Loc, | |
9768 | Left_Opnd => Get_E_Length (T_Typ, 1), | |
9769 | Right_Opnd => | |
9770 | Make_Integer_Literal (Loc, | |
9771 | Intval => | |
9772 | String_Literal_Length (Etype (Expr_Actual)))); | |
9773 | ||
9774 | -- General array case. Here we have a usable actual subtype for | |
9775 | -- the expression, and the condition is built from the two types | |
9776 | -- (Do_Length): | |
9777 | ||
9778 | -- T_Typ'Length /= Exptyp'Length or else | |
9779 | -- T_Typ'Length (2) /= Exptyp'Length (2) or else | |
9780 | -- T_Typ'Length (3) /= Exptyp'Length (3) or else | |
9781 | -- ... | |
9782 | ||
9783 | elsif Is_Constrained (Exptyp) then | |
9784 | declare | |
9dfe12ae | 9785 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
9786 | ||
9787 | L_Index : Node_Id; | |
9788 | R_Index : Node_Id; | |
9789 | L_Low : Node_Id; | |
9790 | L_High : Node_Id; | |
9791 | R_Low : Node_Id; | |
9792 | R_High : Node_Id; | |
ee6ba406 | 9793 | L_Length : Uint; |
9794 | R_Length : Uint; | |
9dfe12ae | 9795 | Ref_Node : Node_Id; |
ee6ba406 | 9796 | |
9797 | begin | |
feff2f05 | 9798 | -- At the library level, we need to ensure that the type of |
9799 | -- the object is elaborated before the check itself is | |
9800 | -- emitted. This is only done if the object is in the | |
9801 | -- current compilation unit, otherwise the type is frozen | |
9802 | -- and elaborated in its unit. | |
9dfe12ae | 9803 | |
9804 | if Is_Itype (Exptyp) | |
9805 | and then | |
9806 | Ekind (Cunit_Entity (Current_Sem_Unit)) = E_Package | |
9807 | and then | |
9808 | not In_Package_Body (Cunit_Entity (Current_Sem_Unit)) | |
d66aa9f6 | 9809 | and then In_Open_Scopes (Scope (Exptyp)) |
9dfe12ae | 9810 | then |
9811 | Ref_Node := Make_Itype_Reference (Sloc (Ck_Node)); | |
9812 | Set_Itype (Ref_Node, Exptyp); | |
9813 | Insert_Action (Ck_Node, Ref_Node); | |
9814 | end if; | |
9815 | ||
ee6ba406 | 9816 | L_Index := First_Index (T_Typ); |
9817 | R_Index := First_Index (Exptyp); | |
9818 | ||
9819 | for Indx in 1 .. Ndims loop | |
9820 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 9821 | or else |
9822 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 9823 | then |
9824 | Get_Index_Bounds (L_Index, L_Low, L_High); | |
9825 | Get_Index_Bounds (R_Index, R_Low, R_High); | |
9826 | ||
9827 | -- Deal with compile time length check. Note that we | |
9828 | -- skip this in the access case, because the access | |
9829 | -- value may be null, so we cannot know statically. | |
9830 | ||
9831 | if not Do_Access | |
9832 | and then Compile_Time_Known_Value (L_Low) | |
9833 | and then Compile_Time_Known_Value (L_High) | |
9834 | and then Compile_Time_Known_Value (R_Low) | |
9835 | and then Compile_Time_Known_Value (R_High) | |
9836 | then | |
9837 | if Expr_Value (L_High) >= Expr_Value (L_Low) then | |
9838 | L_Length := Expr_Value (L_High) - | |
9839 | Expr_Value (L_Low) + 1; | |
9840 | else | |
9841 | L_Length := UI_From_Int (0); | |
9842 | end if; | |
9843 | ||
9844 | if Expr_Value (R_High) >= Expr_Value (R_Low) then | |
9845 | R_Length := Expr_Value (R_High) - | |
9846 | Expr_Value (R_Low) + 1; | |
9847 | else | |
9848 | R_Length := UI_From_Int (0); | |
9849 | end if; | |
9850 | ||
9851 | if L_Length > R_Length then | |
9852 | Add_Check | |
9853 | (Compile_Time_Constraint_Error | |
cb97ae5c | 9854 | (Wnode, "too few elements for}??", T_Typ)); |
ee6ba406 | 9855 | |
b8eacb12 | 9856 | elsif L_Length < R_Length then |
ee6ba406 | 9857 | Add_Check |
9858 | (Compile_Time_Constraint_Error | |
cb97ae5c | 9859 | (Wnode, "too many elements for}??", T_Typ)); |
ee6ba406 | 9860 | end if; |
9861 | ||
9862 | -- The comparison for an individual index subtype | |
9863 | -- is omitted if the corresponding index subtypes | |
9864 | -- statically match, since the result is known to | |
9865 | -- be true. Note that this test is worth while even | |
9866 | -- though we do static evaluation, because non-static | |
9867 | -- subtypes can statically match. | |
9868 | ||
9869 | elsif not | |
9870 | Subtypes_Statically_Match | |
9871 | (Etype (L_Index), Etype (R_Index)) | |
9872 | ||
9873 | and then not | |
9874 | (Same_Bounds (L_Low, R_Low) | |
9875 | and then Same_Bounds (L_High, R_High)) | |
9876 | then | |
9877 | Evolve_Or_Else | |
9878 | (Cond, Length_E_Cond (Exptyp, T_Typ, Indx)); | |
9879 | end if; | |
9880 | ||
9881 | Next (L_Index); | |
9882 | Next (R_Index); | |
9883 | end if; | |
9884 | end loop; | |
9885 | end; | |
9886 | ||
9887 | -- Handle cases where we do not get a usable actual subtype that | |
9888 | -- is constrained. This happens for example in the function call | |
9889 | -- and explicit dereference cases. In these cases, we have to get | |
9890 | -- the length or range from the expression itself, making sure we | |
9891 | -- do not evaluate it more than once. | |
9892 | ||
9893 | -- Here Ck_Node is the original expression, or more properly the | |
feff2f05 | 9894 | -- result of applying Duplicate_Expr to the original tree, forcing |
9895 | -- the result to be a name. | |
ee6ba406 | 9896 | |
9897 | else | |
9898 | declare | |
9dfe12ae | 9899 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 9900 | |
9901 | begin | |
9902 | -- Build the condition for the explicit dereference case | |
9903 | ||
9904 | for Indx in 1 .. Ndims loop | |
9905 | Evolve_Or_Else | |
9906 | (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx)); | |
9907 | end loop; | |
9908 | end; | |
9909 | end if; | |
9910 | end if; | |
9911 | end if; | |
9912 | ||
9913 | -- Construct the test and insert into the tree | |
9914 | ||
9915 | if Present (Cond) then | |
9916 | if Do_Access then | |
9917 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
9918 | end if; | |
9919 | ||
f15731c4 | 9920 | Add_Check |
9921 | (Make_Raise_Constraint_Error (Loc, | |
9922 | Condition => Cond, | |
9923 | Reason => CE_Length_Check_Failed)); | |
ee6ba406 | 9924 | end if; |
9925 | ||
9926 | return Ret_Result; | |
ee6ba406 | 9927 | end Selected_Length_Checks; |
9928 | ||
9929 | --------------------------- | |
9930 | -- Selected_Range_Checks -- | |
9931 | --------------------------- | |
9932 | ||
9933 | function Selected_Range_Checks | |
9934 | (Ck_Node : Node_Id; | |
9935 | Target_Typ : Entity_Id; | |
9936 | Source_Typ : Entity_Id; | |
314a23b6 | 9937 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 9938 | is |
9939 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
9940 | S_Typ : Entity_Id; | |
9941 | T_Typ : Entity_Id; | |
9942 | Expr_Actual : Node_Id; | |
9943 | Exptyp : Entity_Id; | |
9944 | Cond : Node_Id := Empty; | |
9945 | Do_Access : Boolean := False; | |
9946 | Wnode : Node_Id := Warn_Node; | |
9947 | Ret_Result : Check_Result := (Empty, Empty); | |
5bb74b99 | 9948 | Num_Checks : Natural := 0; |
ee6ba406 | 9949 | |
9950 | procedure Add_Check (N : Node_Id); | |
9951 | -- Adds the action given to Ret_Result if N is non-Empty | |
9952 | ||
9953 | function Discrete_Range_Cond | |
9954 | (Expr : Node_Id; | |
314a23b6 | 9955 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 9956 | -- Returns expression to compute: |
9957 | -- Low_Bound (Expr) < Typ'First | |
9958 | -- or else | |
9959 | -- High_Bound (Expr) > Typ'Last | |
9960 | ||
9961 | function Discrete_Expr_Cond | |
9962 | (Expr : Node_Id; | |
314a23b6 | 9963 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 9964 | -- Returns expression to compute: |
9965 | -- Expr < Typ'First | |
9966 | -- or else | |
9967 | -- Expr > Typ'Last | |
9968 | ||
9969 | function Get_E_First_Or_Last | |
3cb12758 | 9970 | (Loc : Source_Ptr; |
9971 | E : Entity_Id; | |
ee6ba406 | 9972 | Indx : Nat; |
314a23b6 | 9973 | Nam : Name_Id) return Node_Id; |
79212397 | 9974 | -- Returns an attribute reference |
ee6ba406 | 9975 | -- E'First or E'Last |
79212397 | 9976 | -- with a source location of Loc. |
f73ee678 | 9977 | -- |
79212397 | 9978 | -- Nam is Name_First or Name_Last, according to which attribute is |
9979 | -- desired. If Indx is non-zero, it is passed as a literal in the | |
9980 | -- Expressions of the attribute reference (identifying the desired | |
9981 | -- array dimension). | |
ee6ba406 | 9982 | |
9983 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id; | |
9984 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id; | |
9985 | -- Returns expression to compute: | |
9dfe12ae | 9986 | -- N'First or N'Last using Duplicate_Subexpr_No_Checks |
ee6ba406 | 9987 | |
9988 | function Range_E_Cond | |
9989 | (Exptyp : Entity_Id; | |
9990 | Typ : Entity_Id; | |
9991 | Indx : Nat) | |
9992 | return Node_Id; | |
9993 | -- Returns expression to compute: | |
9994 | -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last | |
9995 | ||
9996 | function Range_Equal_E_Cond | |
9997 | (Exptyp : Entity_Id; | |
9998 | Typ : Entity_Id; | |
314a23b6 | 9999 | Indx : Nat) return Node_Id; |
ee6ba406 | 10000 | -- Returns expression to compute: |
10001 | -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last | |
10002 | ||
10003 | function Range_N_Cond | |
10004 | (Expr : Node_Id; | |
10005 | Typ : Entity_Id; | |
314a23b6 | 10006 | Indx : Nat) return Node_Id; |
ee6ba406 | 10007 | -- Return expression to compute: |
10008 | -- Expr'First < Typ'First or else Expr'Last > Typ'Last | |
10009 | ||
10010 | --------------- | |
10011 | -- Add_Check -- | |
10012 | --------------- | |
10013 | ||
10014 | procedure Add_Check (N : Node_Id) is | |
10015 | begin | |
10016 | if Present (N) then | |
10017 | ||
10018 | -- For now, ignore attempt to place more than 2 checks ??? | |
10019 | ||
10020 | if Num_Checks = 2 then | |
10021 | return; | |
10022 | end if; | |
10023 | ||
10024 | pragma Assert (Num_Checks <= 1); | |
10025 | Num_Checks := Num_Checks + 1; | |
10026 | Ret_Result (Num_Checks) := N; | |
10027 | end if; | |
10028 | end Add_Check; | |
10029 | ||
10030 | ------------------------- | |
10031 | -- Discrete_Expr_Cond -- | |
10032 | ------------------------- | |
10033 | ||
10034 | function Discrete_Expr_Cond | |
10035 | (Expr : Node_Id; | |
314a23b6 | 10036 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 10037 | is |
10038 | begin | |
10039 | return | |
10040 | Make_Or_Else (Loc, | |
10041 | Left_Opnd => | |
10042 | Make_Op_Lt (Loc, | |
10043 | Left_Opnd => | |
9dfe12ae | 10044 | Convert_To (Base_Type (Typ), |
10045 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 10046 | Right_Opnd => |
10047 | Convert_To (Base_Type (Typ), | |
3cb12758 | 10048 | Get_E_First_Or_Last (Loc, Typ, 0, Name_First))), |
ee6ba406 | 10049 | |
10050 | Right_Opnd => | |
10051 | Make_Op_Gt (Loc, | |
10052 | Left_Opnd => | |
9dfe12ae | 10053 | Convert_To (Base_Type (Typ), |
10054 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 10055 | Right_Opnd => |
10056 | Convert_To | |
10057 | (Base_Type (Typ), | |
3cb12758 | 10058 | Get_E_First_Or_Last (Loc, Typ, 0, Name_Last)))); |
ee6ba406 | 10059 | end Discrete_Expr_Cond; |
10060 | ||
10061 | ------------------------- | |
10062 | -- Discrete_Range_Cond -- | |
10063 | ------------------------- | |
10064 | ||
10065 | function Discrete_Range_Cond | |
10066 | (Expr : Node_Id; | |
314a23b6 | 10067 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 10068 | is |
10069 | LB : Node_Id := Low_Bound (Expr); | |
10070 | HB : Node_Id := High_Bound (Expr); | |
10071 | ||
10072 | Left_Opnd : Node_Id; | |
10073 | Right_Opnd : Node_Id; | |
10074 | ||
10075 | begin | |
10076 | if Nkind (LB) = N_Identifier | |
feff2f05 | 10077 | and then Ekind (Entity (LB)) = E_Discriminant |
10078 | then | |
ee6ba406 | 10079 | LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc); |
10080 | end if; | |
10081 | ||
ee6ba406 | 10082 | Left_Opnd := |
10083 | Make_Op_Lt (Loc, | |
10084 | Left_Opnd => | |
10085 | Convert_To | |
9dfe12ae | 10086 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (LB)), |
ee6ba406 | 10087 | |
10088 | Right_Opnd => | |
10089 | Convert_To | |
3cb12758 | 10090 | (Base_Type (Typ), |
10091 | Get_E_First_Or_Last (Loc, Typ, 0, Name_First))); | |
ee6ba406 | 10092 | |
ba9b1a39 | 10093 | if Nkind (HB) = N_Identifier |
10094 | and then Ekind (Entity (HB)) = E_Discriminant | |
ee6ba406 | 10095 | then |
ba9b1a39 | 10096 | HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc); |
ee6ba406 | 10097 | end if; |
10098 | ||
10099 | Right_Opnd := | |
10100 | Make_Op_Gt (Loc, | |
10101 | Left_Opnd => | |
10102 | Convert_To | |
9dfe12ae | 10103 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (HB)), |
ee6ba406 | 10104 | |
10105 | Right_Opnd => | |
10106 | Convert_To | |
10107 | (Base_Type (Typ), | |
3cb12758 | 10108 | Get_E_First_Or_Last (Loc, Typ, 0, Name_Last))); |
ee6ba406 | 10109 | |
10110 | return Make_Or_Else (Loc, Left_Opnd, Right_Opnd); | |
10111 | end Discrete_Range_Cond; | |
10112 | ||
10113 | ------------------------- | |
10114 | -- Get_E_First_Or_Last -- | |
10115 | ------------------------- | |
10116 | ||
10117 | function Get_E_First_Or_Last | |
3cb12758 | 10118 | (Loc : Source_Ptr; |
10119 | E : Entity_Id; | |
ee6ba406 | 10120 | Indx : Nat; |
314a23b6 | 10121 | Nam : Name_Id) return Node_Id |
ee6ba406 | 10122 | is |
3cb12758 | 10123 | Exprs : List_Id; |
ee6ba406 | 10124 | begin |
3cb12758 | 10125 | if Indx > 0 then |
10126 | Exprs := New_List (Make_Integer_Literal (Loc, UI_From_Int (Indx))); | |
ee6ba406 | 10127 | else |
3cb12758 | 10128 | Exprs := No_List; |
ee6ba406 | 10129 | end if; |
10130 | ||
3cb12758 | 10131 | return Make_Attribute_Reference (Loc, |
10132 | Prefix => New_Occurrence_Of (E, Loc), | |
10133 | Attribute_Name => Nam, | |
10134 | Expressions => Exprs); | |
ee6ba406 | 10135 | end Get_E_First_Or_Last; |
10136 | ||
10137 | ----------------- | |
10138 | -- Get_N_First -- | |
10139 | ----------------- | |
10140 | ||
10141 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is | |
10142 | begin | |
10143 | return | |
10144 | Make_Attribute_Reference (Loc, | |
10145 | Attribute_Name => Name_First, | |
10146 | Prefix => | |
9dfe12ae | 10147 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 10148 | Expressions => New_List ( |
10149 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 10150 | end Get_N_First; |
10151 | ||
10152 | ---------------- | |
10153 | -- Get_N_Last -- | |
10154 | ---------------- | |
10155 | ||
10156 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is | |
10157 | begin | |
10158 | return | |
10159 | Make_Attribute_Reference (Loc, | |
10160 | Attribute_Name => Name_Last, | |
10161 | Prefix => | |
9dfe12ae | 10162 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 10163 | Expressions => New_List ( |
10164 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 10165 | end Get_N_Last; |
10166 | ||
10167 | ------------------ | |
10168 | -- Range_E_Cond -- | |
10169 | ------------------ | |
10170 | ||
10171 | function Range_E_Cond | |
10172 | (Exptyp : Entity_Id; | |
10173 | Typ : Entity_Id; | |
314a23b6 | 10174 | Indx : Nat) return Node_Id |
ee6ba406 | 10175 | is |
10176 | begin | |
10177 | return | |
10178 | Make_Or_Else (Loc, | |
10179 | Left_Opnd => | |
10180 | Make_Op_Lt (Loc, | |
3cb12758 | 10181 | Left_Opnd => |
10182 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First), | |
10183 | Right_Opnd => | |
10184 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
ee6ba406 | 10185 | |
10186 | Right_Opnd => | |
10187 | Make_Op_Gt (Loc, | |
3cb12758 | 10188 | Left_Opnd => |
10189 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last), | |
10190 | Right_Opnd => | |
10191 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 10192 | end Range_E_Cond; |
10193 | ||
10194 | ------------------------ | |
10195 | -- Range_Equal_E_Cond -- | |
10196 | ------------------------ | |
10197 | ||
10198 | function Range_Equal_E_Cond | |
10199 | (Exptyp : Entity_Id; | |
10200 | Typ : Entity_Id; | |
314a23b6 | 10201 | Indx : Nat) return Node_Id |
ee6ba406 | 10202 | is |
10203 | begin | |
10204 | return | |
10205 | Make_Or_Else (Loc, | |
10206 | Left_Opnd => | |
10207 | Make_Op_Ne (Loc, | |
3cb12758 | 10208 | Left_Opnd => |
10209 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First), | |
10210 | Right_Opnd => | |
10211 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
10212 | ||
ee6ba406 | 10213 | Right_Opnd => |
10214 | Make_Op_Ne (Loc, | |
3cb12758 | 10215 | Left_Opnd => |
10216 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last), | |
10217 | Right_Opnd => | |
10218 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 10219 | end Range_Equal_E_Cond; |
10220 | ||
10221 | ------------------ | |
10222 | -- Range_N_Cond -- | |
10223 | ------------------ | |
10224 | ||
10225 | function Range_N_Cond | |
10226 | (Expr : Node_Id; | |
10227 | Typ : Entity_Id; | |
314a23b6 | 10228 | Indx : Nat) return Node_Id |
ee6ba406 | 10229 | is |
10230 | begin | |
10231 | return | |
10232 | Make_Or_Else (Loc, | |
10233 | Left_Opnd => | |
10234 | Make_Op_Lt (Loc, | |
3cb12758 | 10235 | Left_Opnd => |
10236 | Get_N_First (Expr, Indx), | |
10237 | Right_Opnd => | |
10238 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
ee6ba406 | 10239 | |
10240 | Right_Opnd => | |
10241 | Make_Op_Gt (Loc, | |
3cb12758 | 10242 | Left_Opnd => |
10243 | Get_N_Last (Expr, Indx), | |
10244 | Right_Opnd => | |
10245 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 10246 | end Range_N_Cond; |
10247 | ||
10248 | -- Start of processing for Selected_Range_Checks | |
10249 | ||
10250 | begin | |
f0d65dae | 10251 | -- Checks will be applied only when generating code. In GNATprove mode, |
10252 | -- we do not apply the checks, but we still call Selected_Range_Checks | |
10253 | -- to possibly issue errors on SPARK code when a run-time error can be | |
10254 | -- detected at compile time. | |
10255 | ||
10256 | if not Expander_Active and not GNATprove_Mode then | |
ee6ba406 | 10257 | return Ret_Result; |
10258 | end if; | |
10259 | ||
10260 | if Target_Typ = Any_Type | |
10261 | or else Target_Typ = Any_Composite | |
10262 | or else Raises_Constraint_Error (Ck_Node) | |
10263 | then | |
10264 | return Ret_Result; | |
10265 | end if; | |
10266 | ||
10267 | if No (Wnode) then | |
10268 | Wnode := Ck_Node; | |
10269 | end if; | |
10270 | ||
10271 | T_Typ := Target_Typ; | |
10272 | ||
10273 | if No (Source_Typ) then | |
10274 | S_Typ := Etype (Ck_Node); | |
10275 | else | |
10276 | S_Typ := Source_Typ; | |
10277 | end if; | |
10278 | ||
10279 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
10280 | return Ret_Result; | |
10281 | end if; | |
10282 | ||
10283 | -- The order of evaluating T_Typ before S_Typ seems to be critical | |
10284 | -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed | |
10285 | -- in, and since Node can be an N_Range node, it might be invalid. | |
10286 | -- Should there be an assert check somewhere for taking the Etype of | |
10287 | -- an N_Range node ??? | |
10288 | ||
10289 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
10290 | S_Typ := Designated_Type (S_Typ); | |
10291 | T_Typ := Designated_Type (T_Typ); | |
10292 | Do_Access := True; | |
10293 | ||
2af58f67 | 10294 | -- A simple optimization for the null case |
ee6ba406 | 10295 | |
2af58f67 | 10296 | if Known_Null (Ck_Node) then |
ee6ba406 | 10297 | return Ret_Result; |
10298 | end if; | |
10299 | end if; | |
10300 | ||
10301 | -- For an N_Range Node, check for a null range and then if not | |
10302 | -- null generate a range check action. | |
10303 | ||
10304 | if Nkind (Ck_Node) = N_Range then | |
10305 | ||
10306 | -- There's no point in checking a range against itself | |
10307 | ||
10308 | if Ck_Node = Scalar_Range (T_Typ) then | |
10309 | return Ret_Result; | |
10310 | end if; | |
10311 | ||
10312 | declare | |
10313 | T_LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
10314 | T_HB : constant Node_Id := Type_High_Bound (T_Typ); | |
eefa141b | 10315 | Known_T_LB : constant Boolean := Compile_Time_Known_Value (T_LB); |
10316 | Known_T_HB : constant Boolean := Compile_Time_Known_Value (T_HB); | |
ee6ba406 | 10317 | |
eefa141b | 10318 | LB : Node_Id := Low_Bound (Ck_Node); |
10319 | HB : Node_Id := High_Bound (Ck_Node); | |
3fabf0ca | 10320 | Known_LB : Boolean := False; |
10321 | Known_HB : Boolean := False; | |
eefa141b | 10322 | |
10323 | Null_Range : Boolean; | |
ee6ba406 | 10324 | Out_Of_Range_L : Boolean; |
10325 | Out_Of_Range_H : Boolean; | |
10326 | ||
10327 | begin | |
eefa141b | 10328 | -- Compute what is known at compile time |
10329 | ||
10330 | if Known_T_LB and Known_T_HB then | |
10331 | if Compile_Time_Known_Value (LB) then | |
10332 | Known_LB := True; | |
10333 | ||
10334 | -- There's no point in checking that a bound is within its | |
10335 | -- own range so pretend that it is known in this case. First | |
10336 | -- deal with low bound. | |
10337 | ||
10338 | elsif Ekind (Etype (LB)) = E_Signed_Integer_Subtype | |
10339 | and then Scalar_Range (Etype (LB)) = Scalar_Range (T_Typ) | |
10340 | then | |
10341 | LB := T_LB; | |
10342 | Known_LB := True; | |
eefa141b | 10343 | end if; |
10344 | ||
10345 | -- Likewise for the high bound | |
10346 | ||
10347 | if Compile_Time_Known_Value (HB) then | |
10348 | Known_HB := True; | |
10349 | ||
10350 | elsif Ekind (Etype (HB)) = E_Signed_Integer_Subtype | |
10351 | and then Scalar_Range (Etype (HB)) = Scalar_Range (T_Typ) | |
10352 | then | |
10353 | HB := T_HB; | |
10354 | Known_HB := True; | |
eefa141b | 10355 | end if; |
10356 | end if; | |
10357 | ||
10358 | -- Check for case where everything is static and we can do the | |
10359 | -- check at compile time. This is skipped if we have an access | |
10360 | -- type, since the access value may be null. | |
10361 | ||
10362 | -- ??? This code can be improved since you only need to know that | |
10363 | -- the two respective bounds (LB & T_LB or HB & T_HB) are known at | |
10364 | -- compile time to emit pertinent messages. | |
10365 | ||
10366 | if Known_T_LB and Known_T_HB and Known_LB and Known_HB | |
10367 | and not Do_Access | |
ee6ba406 | 10368 | then |
10369 | -- Floating-point case | |
10370 | ||
10371 | if Is_Floating_Point_Type (S_Typ) then | |
10372 | Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB); | |
10373 | Out_Of_Range_L := | |
10374 | (Expr_Value_R (LB) < Expr_Value_R (T_LB)) | |
eefa141b | 10375 | or else |
ee6ba406 | 10376 | (Expr_Value_R (LB) > Expr_Value_R (T_HB)); |
10377 | ||
10378 | Out_Of_Range_H := | |
10379 | (Expr_Value_R (HB) > Expr_Value_R (T_HB)) | |
eefa141b | 10380 | or else |
ee6ba406 | 10381 | (Expr_Value_R (HB) < Expr_Value_R (T_LB)); |
10382 | ||
10383 | -- Fixed or discrete type case | |
10384 | ||
10385 | else | |
10386 | Null_Range := Expr_Value (HB) < Expr_Value (LB); | |
10387 | Out_Of_Range_L := | |
10388 | (Expr_Value (LB) < Expr_Value (T_LB)) | |
eefa141b | 10389 | or else |
ee6ba406 | 10390 | (Expr_Value (LB) > Expr_Value (T_HB)); |
10391 | ||
10392 | Out_Of_Range_H := | |
10393 | (Expr_Value (HB) > Expr_Value (T_HB)) | |
eefa141b | 10394 | or else |
ee6ba406 | 10395 | (Expr_Value (HB) < Expr_Value (T_LB)); |
10396 | end if; | |
10397 | ||
10398 | if not Null_Range then | |
10399 | if Out_Of_Range_L then | |
10400 | if No (Warn_Node) then | |
10401 | Add_Check | |
10402 | (Compile_Time_Constraint_Error | |
10403 | (Low_Bound (Ck_Node), | |
cb97ae5c | 10404 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 10405 | |
10406 | else | |
10407 | Add_Check | |
10408 | (Compile_Time_Constraint_Error | |
10409 | (Wnode, | |
cb97ae5c | 10410 | "static range out of bounds of}??", T_Typ)); |
ee6ba406 | 10411 | end if; |
10412 | end if; | |
10413 | ||
10414 | if Out_Of_Range_H then | |
10415 | if No (Warn_Node) then | |
10416 | Add_Check | |
10417 | (Compile_Time_Constraint_Error | |
10418 | (High_Bound (Ck_Node), | |
cb97ae5c | 10419 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 10420 | |
10421 | else | |
10422 | Add_Check | |
10423 | (Compile_Time_Constraint_Error | |
10424 | (Wnode, | |
cb97ae5c | 10425 | "static range out of bounds of}??", T_Typ)); |
ee6ba406 | 10426 | end if; |
10427 | end if; | |
ee6ba406 | 10428 | end if; |
10429 | ||
10430 | else | |
10431 | declare | |
10432 | LB : Node_Id := Low_Bound (Ck_Node); | |
10433 | HB : Node_Id := High_Bound (Ck_Node); | |
10434 | ||
10435 | begin | |
feff2f05 | 10436 | -- If either bound is a discriminant and we are within the |
10437 | -- record declaration, it is a use of the discriminant in a | |
10438 | -- constraint of a component, and nothing can be checked | |
10439 | -- here. The check will be emitted within the init proc. | |
10440 | -- Before then, the discriminal has no real meaning. | |
10441 | -- Similarly, if the entity is a discriminal, there is no | |
10442 | -- check to perform yet. | |
10443 | ||
10444 | -- The same holds within a discriminated synchronized type, | |
10445 | -- where the discriminant may constrain a component or an | |
10446 | -- entry family. | |
ee6ba406 | 10447 | |
10448 | if Nkind (LB) = N_Identifier | |
0577b0b1 | 10449 | and then Denotes_Discriminant (LB, True) |
ee6ba406 | 10450 | then |
0577b0b1 | 10451 | if Current_Scope = Scope (Entity (LB)) |
10452 | or else Is_Concurrent_Type (Current_Scope) | |
10453 | or else Ekind (Entity (LB)) /= E_Discriminant | |
10454 | then | |
ee6ba406 | 10455 | return Ret_Result; |
10456 | else | |
10457 | LB := | |
10458 | New_Occurrence_Of (Discriminal (Entity (LB)), Loc); | |
10459 | end if; | |
10460 | end if; | |
10461 | ||
10462 | if Nkind (HB) = N_Identifier | |
0577b0b1 | 10463 | and then Denotes_Discriminant (HB, True) |
ee6ba406 | 10464 | then |
0577b0b1 | 10465 | if Current_Scope = Scope (Entity (HB)) |
10466 | or else Is_Concurrent_Type (Current_Scope) | |
10467 | or else Ekind (Entity (HB)) /= E_Discriminant | |
10468 | then | |
ee6ba406 | 10469 | return Ret_Result; |
10470 | else | |
10471 | HB := | |
10472 | New_Occurrence_Of (Discriminal (Entity (HB)), Loc); | |
10473 | end if; | |
10474 | end if; | |
10475 | ||
10476 | Cond := Discrete_Range_Cond (Ck_Node, T_Typ); | |
10477 | Set_Paren_Count (Cond, 1); | |
10478 | ||
10479 | Cond := | |
10480 | Make_And_Then (Loc, | |
10481 | Left_Opnd => | |
10482 | Make_Op_Ge (Loc, | |
86d32751 | 10483 | Left_Opnd => |
10484 | Convert_To (Base_Type (Etype (HB)), | |
10485 | Duplicate_Subexpr_No_Checks (HB)), | |
10486 | Right_Opnd => | |
10487 | Convert_To (Base_Type (Etype (LB)), | |
10488 | Duplicate_Subexpr_No_Checks (LB))), | |
ee6ba406 | 10489 | Right_Opnd => Cond); |
10490 | end; | |
ee6ba406 | 10491 | end if; |
10492 | end; | |
10493 | ||
10494 | elsif Is_Scalar_Type (S_Typ) then | |
10495 | ||
10496 | -- This somewhat duplicates what Apply_Scalar_Range_Check does, | |
10497 | -- except the above simply sets a flag in the node and lets | |
10498 | -- gigi generate the check base on the Etype of the expression. | |
10499 | -- Sometimes, however we want to do a dynamic check against an | |
10500 | -- arbitrary target type, so we do that here. | |
10501 | ||
10502 | if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then | |
10503 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
10504 | ||
10505 | -- For literals, we can tell if the constraint error will be | |
10506 | -- raised at compile time, so we never need a dynamic check, but | |
10507 | -- if the exception will be raised, then post the usual warning, | |
10508 | -- and replace the literal with a raise constraint error | |
10509 | -- expression. As usual, skip this for access types | |
10510 | ||
20cf157b | 10511 | elsif Compile_Time_Known_Value (Ck_Node) and then not Do_Access then |
ee6ba406 | 10512 | declare |
10513 | LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
10514 | UB : constant Node_Id := Type_High_Bound (T_Typ); | |
10515 | ||
10516 | Out_Of_Range : Boolean; | |
10517 | Static_Bounds : constant Boolean := | |
b6341c67 | 10518 | Compile_Time_Known_Value (LB) |
10519 | and Compile_Time_Known_Value (UB); | |
ee6ba406 | 10520 | |
10521 | begin | |
10522 | -- Following range tests should use Sem_Eval routine ??? | |
10523 | ||
10524 | if Static_Bounds then | |
10525 | if Is_Floating_Point_Type (S_Typ) then | |
10526 | Out_Of_Range := | |
10527 | (Expr_Value_R (Ck_Node) < Expr_Value_R (LB)) | |
10528 | or else | |
10529 | (Expr_Value_R (Ck_Node) > Expr_Value_R (UB)); | |
10530 | ||
eefa141b | 10531 | -- Fixed or discrete type |
10532 | ||
10533 | else | |
ee6ba406 | 10534 | Out_Of_Range := |
10535 | Expr_Value (Ck_Node) < Expr_Value (LB) | |
10536 | or else | |
10537 | Expr_Value (Ck_Node) > Expr_Value (UB); | |
10538 | end if; | |
10539 | ||
eefa141b | 10540 | -- Bounds of the type are static and the literal is out of |
10541 | -- range so output a warning message. | |
ee6ba406 | 10542 | |
10543 | if Out_Of_Range then | |
10544 | if No (Warn_Node) then | |
10545 | Add_Check | |
10546 | (Compile_Time_Constraint_Error | |
10547 | (Ck_Node, | |
cb97ae5c | 10548 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 10549 | |
10550 | else | |
10551 | Add_Check | |
10552 | (Compile_Time_Constraint_Error | |
10553 | (Wnode, | |
cb97ae5c | 10554 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 10555 | end if; |
10556 | end if; | |
10557 | ||
10558 | else | |
10559 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
10560 | end if; | |
10561 | end; | |
10562 | ||
10563 | -- Here for the case of a non-static expression, we need a runtime | |
10564 | -- check unless the source type range is guaranteed to be in the | |
10565 | -- range of the target type. | |
10566 | ||
10567 | else | |
7a1dabb3 | 10568 | if not In_Subrange_Of (S_Typ, T_Typ) then |
ee6ba406 | 10569 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); |
10570 | end if; | |
10571 | end if; | |
10572 | end if; | |
10573 | ||
10574 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
10575 | if Is_Constrained (T_Typ) then | |
10576 | ||
10577 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
10578 | Exptyp := Get_Actual_Subtype (Expr_Actual); | |
10579 | ||
10580 | if Is_Access_Type (Exptyp) then | |
10581 | Exptyp := Designated_Type (Exptyp); | |
10582 | end if; | |
10583 | ||
10584 | -- String_Literal case. This needs to be handled specially be- | |
10585 | -- cause no index types are available for string literals. The | |
10586 | -- condition is simply: | |
10587 | ||
10588 | -- T_Typ'Length = string-literal-length | |
10589 | ||
10590 | if Nkind (Expr_Actual) = N_String_Literal then | |
10591 | null; | |
10592 | ||
10593 | -- General array case. Here we have a usable actual subtype for | |
10594 | -- the expression, and the condition is built from the two types | |
10595 | ||
10596 | -- T_Typ'First < Exptyp'First or else | |
10597 | -- T_Typ'Last > Exptyp'Last or else | |
10598 | -- T_Typ'First(1) < Exptyp'First(1) or else | |
10599 | -- T_Typ'Last(1) > Exptyp'Last(1) or else | |
10600 | -- ... | |
10601 | ||
10602 | elsif Is_Constrained (Exptyp) then | |
10603 | declare | |
9dfe12ae | 10604 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
10605 | ||
ee6ba406 | 10606 | L_Index : Node_Id; |
10607 | R_Index : Node_Id; | |
ee6ba406 | 10608 | |
10609 | begin | |
10610 | L_Index := First_Index (T_Typ); | |
10611 | R_Index := First_Index (Exptyp); | |
10612 | ||
10613 | for Indx in 1 .. Ndims loop | |
10614 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 10615 | or else |
10616 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 10617 | then |
ee6ba406 | 10618 | -- Deal with compile time length check. Note that we |
10619 | -- skip this in the access case, because the access | |
10620 | -- value may be null, so we cannot know statically. | |
10621 | ||
10622 | if not | |
10623 | Subtypes_Statically_Match | |
10624 | (Etype (L_Index), Etype (R_Index)) | |
10625 | then | |
10626 | -- If the target type is constrained then we | |
10627 | -- have to check for exact equality of bounds | |
10628 | -- (required for qualified expressions). | |
10629 | ||
10630 | if Is_Constrained (T_Typ) then | |
10631 | Evolve_Or_Else | |
10632 | (Cond, | |
10633 | Range_Equal_E_Cond (Exptyp, T_Typ, Indx)); | |
ee6ba406 | 10634 | else |
10635 | Evolve_Or_Else | |
10636 | (Cond, Range_E_Cond (Exptyp, T_Typ, Indx)); | |
10637 | end if; | |
10638 | end if; | |
10639 | ||
10640 | Next (L_Index); | |
10641 | Next (R_Index); | |
ee6ba406 | 10642 | end if; |
10643 | end loop; | |
10644 | end; | |
10645 | ||
10646 | -- Handle cases where we do not get a usable actual subtype that | |
10647 | -- is constrained. This happens for example in the function call | |
10648 | -- and explicit dereference cases. In these cases, we have to get | |
10649 | -- the length or range from the expression itself, making sure we | |
10650 | -- do not evaluate it more than once. | |
10651 | ||
10652 | -- Here Ck_Node is the original expression, or more properly the | |
10653 | -- result of applying Duplicate_Expr to the original tree, | |
10654 | -- forcing the result to be a name. | |
10655 | ||
10656 | else | |
10657 | declare | |
9dfe12ae | 10658 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 10659 | |
10660 | begin | |
10661 | -- Build the condition for the explicit dereference case | |
10662 | ||
10663 | for Indx in 1 .. Ndims loop | |
10664 | Evolve_Or_Else | |
10665 | (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx)); | |
10666 | end loop; | |
10667 | end; | |
ee6ba406 | 10668 | end if; |
10669 | ||
10670 | else | |
feff2f05 | 10671 | -- For a conversion to an unconstrained array type, generate an |
10672 | -- Action to check that the bounds of the source value are within | |
10673 | -- the constraints imposed by the target type (RM 4.6(38)). No | |
10674 | -- check is needed for a conversion to an access to unconstrained | |
10675 | -- array type, as 4.6(24.15/2) requires the designated subtypes | |
10676 | -- of the two access types to statically match. | |
10677 | ||
10678 | if Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
10679 | and then not Do_Access | |
10680 | then | |
ee6ba406 | 10681 | declare |
10682 | Opnd_Index : Node_Id; | |
10683 | Targ_Index : Node_Id; | |
00c403ee | 10684 | Opnd_Range : Node_Id; |
ee6ba406 | 10685 | |
10686 | begin | |
feff2f05 | 10687 | Opnd_Index := First_Index (Get_Actual_Subtype (Ck_Node)); |
ee6ba406 | 10688 | Targ_Index := First_Index (T_Typ); |
00c403ee | 10689 | while Present (Opnd_Index) loop |
10690 | ||
10691 | -- If the index is a range, use its bounds. If it is an | |
10692 | -- entity (as will be the case if it is a named subtype | |
10693 | -- or an itype created for a slice) retrieve its range. | |
10694 | ||
10695 | if Is_Entity_Name (Opnd_Index) | |
10696 | and then Is_Type (Entity (Opnd_Index)) | |
10697 | then | |
10698 | Opnd_Range := Scalar_Range (Entity (Opnd_Index)); | |
10699 | else | |
10700 | Opnd_Range := Opnd_Index; | |
10701 | end if; | |
10702 | ||
10703 | if Nkind (Opnd_Range) = N_Range then | |
9c486805 | 10704 | if Is_In_Range |
10705 | (Low_Bound (Opnd_Range), Etype (Targ_Index), | |
10706 | Assume_Valid => True) | |
ee6ba406 | 10707 | and then |
10708 | Is_In_Range | |
9c486805 | 10709 | (High_Bound (Opnd_Range), Etype (Targ_Index), |
10710 | Assume_Valid => True) | |
ee6ba406 | 10711 | then |
10712 | null; | |
10713 | ||
feff2f05 | 10714 | -- If null range, no check needed |
f2a06be9 | 10715 | |
9dfe12ae | 10716 | elsif |
00c403ee | 10717 | Compile_Time_Known_Value (High_Bound (Opnd_Range)) |
9dfe12ae | 10718 | and then |
00c403ee | 10719 | Compile_Time_Known_Value (Low_Bound (Opnd_Range)) |
9dfe12ae | 10720 | and then |
00c403ee | 10721 | Expr_Value (High_Bound (Opnd_Range)) < |
10722 | Expr_Value (Low_Bound (Opnd_Range)) | |
9dfe12ae | 10723 | then |
10724 | null; | |
10725 | ||
ee6ba406 | 10726 | elsif Is_Out_Of_Range |
9c486805 | 10727 | (Low_Bound (Opnd_Range), Etype (Targ_Index), |
10728 | Assume_Valid => True) | |
ee6ba406 | 10729 | or else |
10730 | Is_Out_Of_Range | |
9c486805 | 10731 | (High_Bound (Opnd_Range), Etype (Targ_Index), |
10732 | Assume_Valid => True) | |
ee6ba406 | 10733 | then |
10734 | Add_Check | |
10735 | (Compile_Time_Constraint_Error | |
cb97ae5c | 10736 | (Wnode, "value out of range of}??", T_Typ)); |
ee6ba406 | 10737 | |
10738 | else | |
10739 | Evolve_Or_Else | |
10740 | (Cond, | |
10741 | Discrete_Range_Cond | |
00c403ee | 10742 | (Opnd_Range, Etype (Targ_Index))); |
ee6ba406 | 10743 | end if; |
10744 | end if; | |
10745 | ||
10746 | Next_Index (Opnd_Index); | |
10747 | Next_Index (Targ_Index); | |
10748 | end loop; | |
10749 | end; | |
10750 | end if; | |
10751 | end if; | |
10752 | end if; | |
10753 | ||
10754 | -- Construct the test and insert into the tree | |
10755 | ||
10756 | if Present (Cond) then | |
10757 | if Do_Access then | |
10758 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
10759 | end if; | |
10760 | ||
f15731c4 | 10761 | Add_Check |
10762 | (Make_Raise_Constraint_Error (Loc, | |
eefa141b | 10763 | Condition => Cond, |
22d3a5a3 | 10764 | Reason => CE_Range_Check_Failed)); |
ee6ba406 | 10765 | end if; |
10766 | ||
10767 | return Ret_Result; | |
ee6ba406 | 10768 | end Selected_Range_Checks; |
10769 | ||
10770 | ------------------------------- | |
10771 | -- Storage_Checks_Suppressed -- | |
10772 | ------------------------------- | |
10773 | ||
10774 | function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is | |
10775 | begin | |
9dfe12ae | 10776 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
10777 | return Is_Check_Suppressed (E, Storage_Check); | |
10778 | else | |
fafc6b97 | 10779 | return Scope_Suppress.Suppress (Storage_Check); |
9dfe12ae | 10780 | end if; |
ee6ba406 | 10781 | end Storage_Checks_Suppressed; |
10782 | ||
10783 | --------------------------- | |
10784 | -- Tag_Checks_Suppressed -- | |
10785 | --------------------------- | |
10786 | ||
10787 | function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is | |
10788 | begin | |
89f1e35c | 10789 | if Present (E) |
10790 | and then Checks_May_Be_Suppressed (E) | |
10791 | then | |
10792 | return Is_Check_Suppressed (E, Tag_Check); | |
20cf157b | 10793 | else |
10794 | return Scope_Suppress.Suppress (Tag_Check); | |
9dfe12ae | 10795 | end if; |
ee6ba406 | 10796 | end Tag_Checks_Suppressed; |
10797 | ||
7b8fa048 | 10798 | --------------------------------------- |
10799 | -- Validate_Alignment_Check_Warnings -- | |
10800 | --------------------------------------- | |
10801 | ||
10802 | procedure Validate_Alignment_Check_Warnings is | |
10803 | begin | |
10804 | for J in Alignment_Warnings.First .. Alignment_Warnings.Last loop | |
10805 | declare | |
10806 | AWR : Alignment_Warnings_Record | |
10807 | renames Alignment_Warnings.Table (J); | |
10808 | begin | |
10809 | if Known_Alignment (AWR.E) | |
10810 | and then AWR.A mod Alignment (AWR.E) = 0 | |
10811 | then | |
10812 | Delete_Warning_And_Continuations (AWR.W); | |
10813 | end if; | |
10814 | end; | |
10815 | end loop; | |
10816 | end Validate_Alignment_Check_Warnings; | |
10817 | ||
0577b0b1 | 10818 | -------------------------- |
10819 | -- Validity_Check_Range -- | |
10820 | -------------------------- | |
10821 | ||
aaec8d13 | 10822 | procedure Validity_Check_Range |
10823 | (N : Node_Id; | |
10824 | Related_Id : Entity_Id := Empty) | |
10825 | is | |
0577b0b1 | 10826 | begin |
10827 | if Validity_Checks_On and Validity_Check_Operands then | |
10828 | if Nkind (N) = N_Range then | |
aaec8d13 | 10829 | Ensure_Valid |
10830 | (Expr => Low_Bound (N), | |
10831 | Related_Id => Related_Id, | |
10832 | Is_Low_Bound => True); | |
10833 | ||
10834 | Ensure_Valid | |
10835 | (Expr => High_Bound (N), | |
10836 | Related_Id => Related_Id, | |
10837 | Is_High_Bound => True); | |
0577b0b1 | 10838 | end if; |
10839 | end if; | |
10840 | end Validity_Check_Range; | |
10841 | ||
10842 | -------------------------------- | |
10843 | -- Validity_Checks_Suppressed -- | |
10844 | -------------------------------- | |
10845 | ||
10846 | function Validity_Checks_Suppressed (E : Entity_Id) return Boolean is | |
10847 | begin | |
10848 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
10849 | return Is_Check_Suppressed (E, Validity_Check); | |
10850 | else | |
fafc6b97 | 10851 | return Scope_Suppress.Suppress (Validity_Check); |
0577b0b1 | 10852 | end if; |
10853 | end Validity_Checks_Suppressed; | |
10854 | ||
ee6ba406 | 10855 | end Checks; |