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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 | -- -- | |
2b4f2458 | 9 | -- Copyright (C) 1992-2017, 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; |
ee6ba406 | 53 | with Sem_Res; use Sem_Res; |
54 | with Sem_Util; use Sem_Util; | |
55 | with Sem_Warn; use Sem_Warn; | |
56 | with Sinfo; use Sinfo; | |
9dfe12ae | 57 | with Sinput; use Sinput; |
ee6ba406 | 58 | with Snames; use Snames; |
9dfe12ae | 59 | with Sprint; use Sprint; |
ee6ba406 | 60 | with Stand; use Stand; |
bb569db0 | 61 | with Stringt; use Stringt; |
f15731c4 | 62 | with Targparm; use Targparm; |
ee6ba406 | 63 | with Tbuild; use Tbuild; |
64 | with Ttypes; use Ttypes; | |
ee6ba406 | 65 | with Validsw; use Validsw; |
66 | ||
67 | package body Checks is | |
68 | ||
69 | -- General note: many of these routines are concerned with generating | |
70 | -- checking code to make sure that constraint error is raised at runtime. | |
71 | -- Clearly this code is only needed if the expander is active, since | |
72 | -- otherwise we will not be generating code or going into the runtime | |
73 | -- execution anyway. | |
74 | ||
75 | -- We therefore disconnect most of these checks if the expander is | |
76 | -- inactive. This has the additional benefit that we do not need to | |
77 | -- worry about the tree being messed up by previous errors (since errors | |
78 | -- turn off expansion anyway). | |
79 | ||
80 | -- There are a few exceptions to the above rule. For instance routines | |
81 | -- such as Apply_Scalar_Range_Check that do not insert any code can be | |
82 | -- safely called even when the Expander is inactive (but Errors_Detected | |
83 | -- is 0). The benefit of executing this code when expansion is off, is | |
84 | -- the ability to emit constraint error warning for static expressions | |
85 | -- even when we are not generating code. | |
86 | ||
20cf157b | 87 | -- The above is modified in gnatprove mode to ensure that proper check |
88 | -- flags are always placed, even if expansion is off. | |
89 | ||
9dfe12ae | 90 | ------------------------------------- |
91 | -- Suppression of Redundant Checks -- | |
92 | ------------------------------------- | |
93 | ||
94 | -- This unit implements a limited circuit for removal of redundant | |
95 | -- checks. The processing is based on a tracing of simple sequential | |
96 | -- flow. For any sequence of statements, we save expressions that are | |
97 | -- marked to be checked, and then if the same expression appears later | |
98 | -- with the same check, then under certain circumstances, the second | |
99 | -- check can be suppressed. | |
100 | ||
101 | -- Basically, we can suppress the check if we know for certain that | |
102 | -- the previous expression has been elaborated (together with its | |
103 | -- check), and we know that the exception frame is the same, and that | |
104 | -- nothing has happened to change the result of the exception. | |
105 | ||
106 | -- Let us examine each of these three conditions in turn to describe | |
107 | -- how we ensure that this condition is met. | |
108 | ||
109 | -- First, we need to know for certain that the previous expression has | |
6fb3c314 | 110 | -- been executed. This is done principally by the mechanism of calling |
9dfe12ae | 111 | -- Conditional_Statements_Begin at the start of any statement sequence |
112 | -- and Conditional_Statements_End at the end. The End call causes all | |
113 | -- checks remembered since the Begin call to be discarded. This does | |
114 | -- miss a few cases, notably the case of a nested BEGIN-END block with | |
115 | -- no exception handlers. But the important thing is to be conservative. | |
116 | -- The other protection is that all checks are discarded if a label | |
117 | -- is encountered, since then the assumption of sequential execution | |
118 | -- is violated, and we don't know enough about the flow. | |
119 | ||
120 | -- Second, we need to know that the exception frame is the same. We | |
121 | -- do this by killing all remembered checks when we enter a new frame. | |
122 | -- Again, that's over-conservative, but generally the cases we can help | |
123 | -- with are pretty local anyway (like the body of a loop for example). | |
124 | ||
125 | -- Third, we must be sure to forget any checks which are no longer valid. | |
126 | -- This is done by two mechanisms, first the Kill_Checks_Variable call is | |
127 | -- used to note any changes to local variables. We only attempt to deal | |
128 | -- with checks involving local variables, so we do not need to worry | |
129 | -- about global variables. Second, a call to any non-global procedure | |
130 | -- causes us to abandon all stored checks, since such a all may affect | |
131 | -- the values of any local variables. | |
132 | ||
133 | -- The following define the data structures used to deal with remembering | |
134 | -- checks so that redundant checks can be eliminated as described above. | |
135 | ||
136 | -- Right now, the only expressions that we deal with are of the form of | |
137 | -- simple local objects (either declared locally, or IN parameters) or | |
138 | -- such objects plus/minus a compile time known constant. We can do | |
139 | -- more later on if it seems worthwhile, but this catches many simple | |
140 | -- cases in practice. | |
141 | ||
142 | -- The following record type reflects a single saved check. An entry | |
143 | -- is made in the stack of saved checks if and only if the expression | |
144 | -- has been elaborated with the indicated checks. | |
145 | ||
146 | type Saved_Check is record | |
147 | Killed : Boolean; | |
148 | -- Set True if entry is killed by Kill_Checks | |
149 | ||
150 | Entity : Entity_Id; | |
151 | -- The entity involved in the expression that is checked | |
152 | ||
153 | Offset : Uint; | |
154 | -- A compile time value indicating the result of adding or | |
155 | -- subtracting a compile time value. This value is to be | |
156 | -- added to the value of the Entity. A value of zero is | |
157 | -- used for the case of a simple entity reference. | |
158 | ||
159 | Check_Type : Character; | |
160 | -- This is set to 'R' for a range check (in which case Target_Type | |
161 | -- is set to the target type for the range check) or to 'O' for an | |
162 | -- overflow check (in which case Target_Type is set to Empty). | |
163 | ||
164 | Target_Type : Entity_Id; | |
165 | -- Used only if Do_Range_Check is set. Records the target type for | |
166 | -- the check. We need this, because a check is a duplicate only if | |
6fb3c314 | 167 | -- it has the same target type (or more accurately one with a |
9dfe12ae | 168 | -- range that is smaller or equal to the stored target type of a |
169 | -- saved check). | |
170 | end record; | |
171 | ||
172 | -- The following table keeps track of saved checks. Rather than use an | |
bbbfe30c | 173 | -- extensible table, we just use a table of fixed size, and we discard |
9dfe12ae | 174 | -- any saved checks that do not fit. That's very unlikely to happen and |
175 | -- this is only an optimization in any case. | |
176 | ||
177 | Saved_Checks : array (Int range 1 .. 200) of Saved_Check; | |
178 | -- Array of saved checks | |
179 | ||
180 | Num_Saved_Checks : Nat := 0; | |
181 | -- Number of saved checks | |
182 | ||
183 | -- The following stack keeps track of statement ranges. It is treated | |
184 | -- as a stack. When Conditional_Statements_Begin is called, an entry | |
185 | -- is pushed onto this stack containing the value of Num_Saved_Checks | |
186 | -- at the time of the call. Then when Conditional_Statements_End is | |
187 | -- called, this value is popped off and used to reset Num_Saved_Checks. | |
188 | ||
189 | -- Note: again, this is a fixed length stack with a size that should | |
190 | -- always be fine. If the value of the stack pointer goes above the | |
191 | -- limit, then we just forget all saved checks. | |
192 | ||
193 | Saved_Checks_Stack : array (Int range 1 .. 100) of Nat; | |
194 | Saved_Checks_TOS : Nat := 0; | |
195 | ||
196 | ----------------------- | |
197 | -- Local Subprograms -- | |
198 | ----------------------- | |
ee6ba406 | 199 | |
0df9d43f | 200 | procedure Apply_Arithmetic_Overflow_Strict (N : Node_Id); |
3cce7f32 | 201 | -- Used to apply arithmetic overflow checks for all cases except operators |
691fe9e0 | 202 | -- on signed arithmetic types in MINIMIZED/ELIMINATED case (for which we |
0df9d43f | 203 | -- call Apply_Arithmetic_Overflow_Minimized_Eliminated below). N can be a |
204 | -- signed integer arithmetic operator (but not an if or case expression). | |
205 | -- It is also called for types other than signed integers. | |
3cce7f32 | 206 | |
207 | procedure Apply_Arithmetic_Overflow_Minimized_Eliminated (Op : Node_Id); | |
208 | -- Used to apply arithmetic overflow checks for the case where the overflow | |
0df9d43f | 209 | -- checking mode is MINIMIZED or ELIMINATED and we have a signed integer |
210 | -- arithmetic op (which includes the case of if and case expressions). Note | |
211 | -- that Do_Overflow_Check may or may not be set for node Op. In these modes | |
212 | -- we have work to do even if overflow checking is suppressed. | |
3cce7f32 | 213 | |
2fe22c69 | 214 | procedure Apply_Division_Check |
215 | (N : Node_Id; | |
216 | Rlo : Uint; | |
217 | Rhi : Uint; | |
218 | ROK : Boolean); | |
219 | -- N is an N_Op_Div, N_Op_Rem, or N_Op_Mod node. This routine applies | |
220 | -- division checks as required if the Do_Division_Check flag is set. | |
221 | -- Rlo and Rhi give the possible range of the right operand, these values | |
222 | -- can be referenced and trusted only if ROK is set True. | |
223 | ||
224 | procedure Apply_Float_Conversion_Check | |
225 | (Ck_Node : Node_Id; | |
226 | Target_Typ : Entity_Id); | |
227 | -- The checks on a conversion from a floating-point type to an integer | |
228 | -- type are delicate. They have to be performed before conversion, they | |
229 | -- have to raise an exception when the operand is a NaN, and rounding must | |
230 | -- be taken into account to determine the safe bounds of the operand. | |
231 | ||
ee6ba406 | 232 | procedure Apply_Selected_Length_Checks |
233 | (Ck_Node : Node_Id; | |
234 | Target_Typ : Entity_Id; | |
235 | Source_Typ : Entity_Id; | |
236 | Do_Static : Boolean); | |
237 | -- This is the subprogram that does all the work for Apply_Length_Check | |
238 | -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as | |
239 | -- described for the above routines. The Do_Static flag indicates that | |
240 | -- only a static check is to be done. | |
241 | ||
242 | procedure Apply_Selected_Range_Checks | |
243 | (Ck_Node : Node_Id; | |
244 | Target_Typ : Entity_Id; | |
245 | Source_Typ : Entity_Id; | |
246 | Do_Static : Boolean); | |
247 | -- This is the subprogram that does all the work for Apply_Range_Check. | |
248 | -- Expr, Target_Typ and Source_Typ are as described for the above | |
249 | -- routine. The Do_Static flag indicates that only a static check is | |
250 | -- to be done. | |
251 | ||
2af58f67 | 252 | type Check_Type is new Check_Id range Access_Check .. Division_Check; |
13dbf220 | 253 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean; |
254 | -- This function is used to see if an access or division by zero check is | |
255 | -- needed. The check is to be applied to a single variable appearing in the | |
256 | -- source, and N is the node for the reference. If N is not of this form, | |
257 | -- True is returned with no further processing. If N is of the right form, | |
258 | -- then further processing determines if the given Check is needed. | |
259 | -- | |
260 | -- The particular circuit is to see if we have the case of a check that is | |
261 | -- not needed because it appears in the right operand of a short circuited | |
262 | -- conditional where the left operand guards the check. For example: | |
263 | -- | |
264 | -- if Var = 0 or else Q / Var > 12 then | |
265 | -- ... | |
266 | -- end if; | |
267 | -- | |
268 | -- In this example, the division check is not required. At the same time | |
269 | -- we can issue warnings for suspicious use of non-short-circuited forms, | |
270 | -- such as: | |
271 | -- | |
272 | -- if Var = 0 or Q / Var > 12 then | |
273 | -- ... | |
274 | -- end if; | |
275 | ||
9dfe12ae | 276 | procedure Find_Check |
277 | (Expr : Node_Id; | |
278 | Check_Type : Character; | |
279 | Target_Type : Entity_Id; | |
280 | Entry_OK : out Boolean; | |
281 | Check_Num : out Nat; | |
282 | Ent : out Entity_Id; | |
283 | Ofs : out Uint); | |
284 | -- This routine is used by Enable_Range_Check and Enable_Overflow_Check | |
285 | -- to see if a check is of the form for optimization, and if so, to see | |
286 | -- if it has already been performed. Expr is the expression to check, | |
287 | -- and Check_Type is 'R' for a range check, 'O' for an overflow check. | |
288 | -- Target_Type is the target type for a range check, and Empty for an | |
289 | -- overflow check. If the entry is not of the form for optimization, | |
290 | -- then Entry_OK is set to False, and the remaining out parameters | |
291 | -- are undefined. If the entry is OK, then Ent/Ofs are set to the | |
292 | -- entity and offset from the expression. Check_Num is the number of | |
293 | -- a matching saved entry in Saved_Checks, or zero if no such entry | |
294 | -- is located. | |
295 | ||
ee6ba406 | 296 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id; |
297 | -- If a discriminal is used in constraining a prival, Return reference | |
298 | -- to the discriminal of the protected body (which renames the parameter | |
299 | -- of the enclosing protected operation). This clumsy transformation is | |
300 | -- needed because privals are created too late and their actual subtypes | |
301 | -- are not available when analysing the bodies of the protected operations. | |
0577b0b1 | 302 | -- This function is called whenever the bound is an entity and the scope |
303 | -- indicates a protected operation. If the bound is an in-parameter of | |
304 | -- a protected operation that is not a prival, the function returns the | |
305 | -- bound itself. | |
ee6ba406 | 306 | -- To be cleaned up??? |
307 | ||
308 | function Guard_Access | |
309 | (Cond : Node_Id; | |
310 | Loc : Source_Ptr; | |
314a23b6 | 311 | Ck_Node : Node_Id) return Node_Id; |
ee6ba406 | 312 | -- In the access type case, guard the test with a test to ensure |
313 | -- that the access value is non-null, since the checks do not | |
314 | -- not apply to null access values. | |
315 | ||
316 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr); | |
317 | -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the | |
318 | -- Constraint_Error node. | |
319 | ||
3cce7f32 | 320 | function Is_Signed_Integer_Arithmetic_Op (N : Node_Id) return Boolean; |
321 | -- Returns True if node N is for an arithmetic operation with signed | |
0326b4d4 | 322 | -- integer operands. This includes unary and binary operators, and also |
323 | -- if and case expression nodes where the dependent expressions are of | |
324 | -- a signed integer type. These are the kinds of nodes for which special | |
691fe9e0 | 325 | -- handling applies in MINIMIZED or ELIMINATED overflow checking mode. |
3cce7f32 | 326 | |
0577b0b1 | 327 | function Range_Or_Validity_Checks_Suppressed |
328 | (Expr : Node_Id) return Boolean; | |
329 | -- Returns True if either range or validity checks or both are suppressed | |
330 | -- for the type of the given expression, or, if the expression is the name | |
331 | -- of an entity, if these checks are suppressed for the entity. | |
332 | ||
ee6ba406 | 333 | function Selected_Length_Checks |
334 | (Ck_Node : Node_Id; | |
335 | Target_Typ : Entity_Id; | |
336 | Source_Typ : Entity_Id; | |
314a23b6 | 337 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 338 | -- Like Apply_Selected_Length_Checks, except it doesn't modify |
339 | -- anything, just returns a list of nodes as described in the spec of | |
340 | -- this package for the Range_Check function. | |
18cb6d78 | 341 | -- ??? In fact it does construct the test and insert it into the tree, |
342 | -- and insert actions in various ways (calling Insert_Action directly | |
343 | -- in particular) so we do not call it in GNATprove mode, contrary to | |
344 | -- Selected_Range_Checks. | |
ee6ba406 | 345 | |
346 | function Selected_Range_Checks | |
347 | (Ck_Node : Node_Id; | |
348 | Target_Typ : Entity_Id; | |
349 | Source_Typ : Entity_Id; | |
314a23b6 | 350 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 351 | -- Like Apply_Selected_Range_Checks, except it doesn't modify anything, |
352 | -- just returns a list of nodes as described in the spec of this package | |
353 | -- for the Range_Check function. | |
354 | ||
355 | ------------------------------ | |
356 | -- Access_Checks_Suppressed -- | |
357 | ------------------------------ | |
358 | ||
359 | function Access_Checks_Suppressed (E : Entity_Id) return Boolean is | |
360 | begin | |
9dfe12ae | 361 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
362 | return Is_Check_Suppressed (E, Access_Check); | |
363 | else | |
fafc6b97 | 364 | return Scope_Suppress.Suppress (Access_Check); |
9dfe12ae | 365 | end if; |
ee6ba406 | 366 | end Access_Checks_Suppressed; |
367 | ||
368 | ------------------------------------- | |
369 | -- Accessibility_Checks_Suppressed -- | |
370 | ------------------------------------- | |
371 | ||
372 | function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is | |
373 | begin | |
9dfe12ae | 374 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
375 | return Is_Check_Suppressed (E, Accessibility_Check); | |
376 | else | |
fafc6b97 | 377 | return Scope_Suppress.Suppress (Accessibility_Check); |
9dfe12ae | 378 | end if; |
ee6ba406 | 379 | end Accessibility_Checks_Suppressed; |
380 | ||
00c403ee | 381 | ----------------------------- |
382 | -- Activate_Division_Check -- | |
383 | ----------------------------- | |
384 | ||
385 | procedure Activate_Division_Check (N : Node_Id) is | |
386 | begin | |
387 | Set_Do_Division_Check (N, True); | |
388 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
389 | end Activate_Division_Check; | |
390 | ||
391 | ----------------------------- | |
392 | -- Activate_Overflow_Check -- | |
393 | ----------------------------- | |
394 | ||
395 | procedure Activate_Overflow_Check (N : Node_Id) is | |
c8e92b5f | 396 | Typ : constant Entity_Id := Etype (N); |
397 | ||
00c403ee | 398 | begin |
c8e92b5f | 399 | -- Floating-point case. If Etype is not set (this can happen when we |
400 | -- activate a check on a node that has not yet been analyzed), then | |
401 | -- we assume we do not have a floating-point type (as per our spec). | |
402 | ||
403 | if Present (Typ) and then Is_Floating_Point_Type (Typ) then | |
404 | ||
405 | -- Ignore call if we have no automatic overflow checks on the target | |
406 | -- and Check_Float_Overflow mode is not set. These are the cases in | |
407 | -- which we expect to generate infinities and NaN's with no check. | |
408 | ||
409 | if not (Machine_Overflows_On_Target or Check_Float_Overflow) then | |
410 | return; | |
411 | ||
412 | -- Ignore for unary operations ("+", "-", abs) since these can never | |
413 | -- result in overflow for floating-point cases. | |
b8446e0d | 414 | |
c8e92b5f | 415 | elsif Nkind (N) in N_Unary_Op then |
416 | return; | |
417 | ||
418 | -- Otherwise we will set the flag | |
419 | ||
420 | else | |
421 | null; | |
422 | end if; | |
423 | ||
424 | -- Discrete case | |
425 | ||
426 | else | |
427 | -- Nothing to do for Rem/Mod/Plus (overflow not possible, the check | |
428 | -- for zero-divide is a divide check, not an overflow check). | |
b8446e0d | 429 | |
c8e92b5f | 430 | if Nkind_In (N, N_Op_Rem, N_Op_Mod, N_Op_Plus) then |
431 | return; | |
432 | end if; | |
b8446e0d | 433 | end if; |
434 | ||
c8e92b5f | 435 | -- Fall through for cases where we do set the flag |
b8446e0d | 436 | |
437 | Set_Do_Overflow_Check (N, True); | |
438 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
00c403ee | 439 | end Activate_Overflow_Check; |
440 | ||
441 | -------------------------- | |
442 | -- Activate_Range_Check -- | |
443 | -------------------------- | |
444 | ||
445 | procedure Activate_Range_Check (N : Node_Id) is | |
446 | begin | |
447 | Set_Do_Range_Check (N, True); | |
448 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
449 | end Activate_Range_Check; | |
450 | ||
0577b0b1 | 451 | --------------------------------- |
452 | -- Alignment_Checks_Suppressed -- | |
453 | --------------------------------- | |
454 | ||
455 | function Alignment_Checks_Suppressed (E : Entity_Id) return Boolean is | |
456 | begin | |
457 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
458 | return Is_Check_Suppressed (E, Alignment_Check); | |
459 | else | |
fafc6b97 | 460 | return Scope_Suppress.Suppress (Alignment_Check); |
0577b0b1 | 461 | end if; |
462 | end Alignment_Checks_Suppressed; | |
463 | ||
2d70530c | 464 | ---------------------------------- |
465 | -- Allocation_Checks_Suppressed -- | |
466 | ---------------------------------- | |
467 | ||
fa771c05 | 468 | -- Note: at the current time there are no calls to this function, because |
469 | -- the relevant check is in the run-time, so it is not a check that the | |
470 | -- compiler can suppress anyway, but we still have to recognize the check | |
471 | -- name Allocation_Check since it is part of the standard. | |
472 | ||
2d70530c | 473 | function Allocation_Checks_Suppressed (E : Entity_Id) return Boolean is |
474 | begin | |
475 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
476 | return Is_Check_Suppressed (E, Allocation_Check); | |
477 | else | |
478 | return Scope_Suppress.Suppress (Allocation_Check); | |
479 | end if; | |
480 | end Allocation_Checks_Suppressed; | |
481 | ||
ee6ba406 | 482 | ------------------------- |
483 | -- Append_Range_Checks -- | |
484 | ------------------------- | |
485 | ||
486 | procedure Append_Range_Checks | |
487 | (Checks : Check_Result; | |
488 | Stmts : List_Id; | |
489 | Suppress_Typ : Entity_Id; | |
490 | Static_Sloc : Source_Ptr; | |
491 | Flag_Node : Node_Id) | |
492 | is | |
2b4f2458 | 493 | Checks_On : constant Boolean := |
494 | not Index_Checks_Suppressed (Suppress_Typ) | |
495 | or else | |
496 | not Range_Checks_Suppressed (Suppress_Typ); | |
497 | ||
9dfe12ae | 498 | Internal_Flag_Node : constant Node_Id := Flag_Node; |
499 | Internal_Static_Sloc : constant Source_Ptr := Static_Sloc; | |
500 | ||
ee6ba406 | 501 | begin |
2b4f2458 | 502 | -- For now we just return if Checks_On is false, however this should be |
503 | -- enhanced to check for an always True value in the condition and to | |
504 | -- generate a compilation warning??? | |
ee6ba406 | 505 | |
506 | if not Checks_On then | |
507 | return; | |
508 | end if; | |
509 | ||
510 | for J in 1 .. 2 loop | |
511 | exit when No (Checks (J)); | |
512 | ||
513 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
514 | and then Present (Condition (Checks (J))) | |
515 | then | |
516 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
517 | Append_To (Stmts, Checks (J)); | |
518 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
519 | end if; | |
520 | ||
521 | else | |
522 | Append_To | |
f15731c4 | 523 | (Stmts, |
524 | Make_Raise_Constraint_Error (Internal_Static_Sloc, | |
525 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 526 | end if; |
527 | end loop; | |
528 | end Append_Range_Checks; | |
529 | ||
530 | ------------------------ | |
531 | -- Apply_Access_Check -- | |
532 | ------------------------ | |
533 | ||
534 | procedure Apply_Access_Check (N : Node_Id) is | |
535 | P : constant Node_Id := Prefix (N); | |
536 | ||
537 | begin | |
13dbf220 | 538 | -- We do not need checks if we are not generating code (i.e. the |
539 | -- expander is not active). This is not just an optimization, there | |
540 | -- are cases (e.g. with pragma Debug) where generating the checks | |
541 | -- can cause real trouble). | |
284faf8b | 542 | |
a33565dd | 543 | if not Expander_Active then |
13dbf220 | 544 | return; |
9dfe12ae | 545 | end if; |
ee6ba406 | 546 | |
84d0d4a5 | 547 | -- No check if short circuiting makes check unnecessary |
9dfe12ae | 548 | |
84d0d4a5 | 549 | if not Check_Needed (P, Access_Check) then |
550 | return; | |
ee6ba406 | 551 | end if; |
9dfe12ae | 552 | |
cc60bd16 | 553 | -- No check if accessing the Offset_To_Top component of a dispatch |
554 | -- table. They are safe by construction. | |
555 | ||
040277b1 | 556 | if Tagged_Type_Expansion |
557 | and then Present (Etype (P)) | |
cc60bd16 | 558 | and then RTU_Loaded (Ada_Tags) |
559 | and then RTE_Available (RE_Offset_To_Top_Ptr) | |
560 | and then Etype (P) = RTE (RE_Offset_To_Top_Ptr) | |
561 | then | |
562 | return; | |
563 | end if; | |
564 | ||
84d0d4a5 | 565 | -- Otherwise go ahead and install the check |
9dfe12ae | 566 | |
fa7497e8 | 567 | Install_Null_Excluding_Check (P); |
ee6ba406 | 568 | end Apply_Access_Check; |
569 | ||
570 | ------------------------------- | |
571 | -- Apply_Accessibility_Check -- | |
572 | ------------------------------- | |
573 | ||
55dc6dc2 | 574 | procedure Apply_Accessibility_Check |
575 | (N : Node_Id; | |
576 | Typ : Entity_Id; | |
577 | Insert_Node : Node_Id) | |
578 | is | |
ee6ba406 | 579 | Loc : constant Source_Ptr := Sloc (N); |
1a9cc6cd | 580 | Param_Ent : Entity_Id := Param_Entity (N); |
ee6ba406 | 581 | Param_Level : Node_Id; |
582 | Type_Level : Node_Id; | |
583 | ||
584 | begin | |
47d210a3 | 585 | if Ada_Version >= Ada_2012 |
586 | and then not Present (Param_Ent) | |
587 | and then Is_Entity_Name (N) | |
588 | and then Ekind_In (Entity (N), E_Constant, E_Variable) | |
589 | and then Present (Effective_Extra_Accessibility (Entity (N))) | |
590 | then | |
591 | Param_Ent := Entity (N); | |
592 | while Present (Renamed_Object (Param_Ent)) loop | |
1a9cc6cd | 593 | |
47d210a3 | 594 | -- Renamed_Object must return an Entity_Name here |
595 | -- because of preceding "Present (E_E_A (...))" test. | |
596 | ||
597 | Param_Ent := Entity (Renamed_Object (Param_Ent)); | |
598 | end loop; | |
599 | end if; | |
600 | ||
ee6ba406 | 601 | if Inside_A_Generic then |
602 | return; | |
603 | ||
6ffc64fc | 604 | -- Only apply the run-time check if the access parameter has an |
605 | -- associated extra access level parameter and when the level of the | |
606 | -- type is less deep than the level of the access parameter, and | |
607 | -- accessibility checks are not suppressed. | |
ee6ba406 | 608 | |
609 | elsif Present (Param_Ent) | |
610 | and then Present (Extra_Accessibility (Param_Ent)) | |
47d210a3 | 611 | and then UI_Gt (Object_Access_Level (N), |
1a9cc6cd | 612 | Deepest_Type_Access_Level (Typ)) |
ee6ba406 | 613 | and then not Accessibility_Checks_Suppressed (Param_Ent) |
614 | and then not Accessibility_Checks_Suppressed (Typ) | |
615 | then | |
616 | Param_Level := | |
617 | New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc); | |
618 | ||
1a9cc6cd | 619 | Type_Level := |
620 | Make_Integer_Literal (Loc, Deepest_Type_Access_Level (Typ)); | |
ee6ba406 | 621 | |
bf3e1520 | 622 | -- Raise Program_Error if the accessibility level of the access |
84d0d4a5 | 623 | -- parameter is deeper than the level of the target access type. |
ee6ba406 | 624 | |
55dc6dc2 | 625 | Insert_Action (Insert_Node, |
ee6ba406 | 626 | Make_Raise_Program_Error (Loc, |
627 | Condition => | |
628 | Make_Op_Gt (Loc, | |
629 | Left_Opnd => Param_Level, | |
f15731c4 | 630 | Right_Opnd => Type_Level), |
631 | Reason => PE_Accessibility_Check_Failed)); | |
ee6ba406 | 632 | |
633 | Analyze_And_Resolve (N); | |
634 | end if; | |
635 | end Apply_Accessibility_Check; | |
636 | ||
0577b0b1 | 637 | -------------------------------- |
638 | -- Apply_Address_Clause_Check -- | |
639 | -------------------------------- | |
640 | ||
641 | procedure Apply_Address_Clause_Check (E : Entity_Id; N : Node_Id) is | |
d950dc79 | 642 | pragma Assert (Nkind (N) = N_Freeze_Entity); |
643 | ||
8650387e | 644 | AC : constant Node_Id := Address_Clause (E); |
645 | Loc : constant Source_Ptr := Sloc (AC); | |
646 | Typ : constant Entity_Id := Etype (E); | |
c2b56224 | 647 | |
c2b56224 | 648 | Expr : Node_Id; |
0577b0b1 | 649 | -- Address expression (not necessarily the same as Aexp, for example |
650 | -- when Aexp is a reference to a constant, in which case Expr gets | |
7b8fa048 | 651 | -- reset to reference the value expression of the constant). |
0577b0b1 | 652 | |
c2b56224 | 653 | begin |
d6da7448 | 654 | -- See if alignment check needed. Note that we never need a check if the |
655 | -- maximum alignment is one, since the check will always succeed. | |
656 | ||
657 | -- Note: we do not check for checks suppressed here, since that check | |
658 | -- was done in Sem_Ch13 when the address clause was processed. We are | |
659 | -- only called if checks were not suppressed. The reason for this is | |
660 | -- that we have to delay the call to Apply_Alignment_Check till freeze | |
661 | -- time (so that all types etc are elaborated), but we have to check | |
662 | -- the status of check suppressing at the point of the address clause. | |
663 | ||
664 | if No (AC) | |
665 | or else not Check_Address_Alignment (AC) | |
666 | or else Maximum_Alignment = 1 | |
667 | then | |
668 | return; | |
669 | end if; | |
670 | ||
671 | -- Obtain expression from address clause | |
9dfe12ae | 672 | |
514a5555 | 673 | Expr := Address_Value (Expression (AC)); |
0577b0b1 | 674 | |
514a5555 | 675 | -- See if we know that Expr has an acceptable value at compile time. If |
676 | -- it hasn't or we don't know, we defer issuing the warning until the | |
677 | -- end of the compilation to take into account back end annotations. | |
c2b56224 | 678 | |
679 | if Compile_Time_Known_Value (Expr) | |
f2a06be9 | 680 | and then (Known_Alignment (E) or else Known_Alignment (Typ)) |
c2b56224 | 681 | then |
f2a06be9 | 682 | declare |
683 | AL : Uint := Alignment (Typ); | |
684 | ||
685 | begin | |
8650387e | 686 | -- The object alignment might be more restrictive than the type |
687 | -- alignment. | |
f2a06be9 | 688 | |
689 | if Known_Alignment (E) then | |
690 | AL := Alignment (E); | |
691 | end if; | |
692 | ||
514a5555 | 693 | if Expr_Value (Expr) mod AL = 0 then |
0577b0b1 | 694 | return; |
f2a06be9 | 695 | end if; |
696 | end; | |
c2b56224 | 697 | |
7161e166 | 698 | -- If the expression has the form X'Address, then we can find out if the |
699 | -- object X has an alignment that is compatible with the object E. If it | |
700 | -- hasn't or we don't know, we defer issuing the warning until the end | |
701 | -- of the compilation to take into account back end annotations. | |
c2b56224 | 702 | |
0577b0b1 | 703 | elsif Nkind (Expr) = N_Attribute_Reference |
704 | and then Attribute_Name (Expr) = Name_Address | |
7161e166 | 705 | and then |
706 | Has_Compatible_Alignment (E, Prefix (Expr), False) = Known_Compatible | |
0577b0b1 | 707 | then |
d6da7448 | 708 | return; |
0577b0b1 | 709 | end if; |
c2b56224 | 710 | |
6fb3c314 | 711 | -- Here we do not know if the value is acceptable. Strictly we don't |
712 | -- have to do anything, since if the alignment is bad, we have an | |
713 | -- erroneous program. However we are allowed to check for erroneous | |
714 | -- conditions and we decide to do this by default if the check is not | |
715 | -- suppressed. | |
0577b0b1 | 716 | |
717 | -- However, don't do the check if elaboration code is unwanted | |
718 | ||
719 | if Restriction_Active (No_Elaboration_Code) then | |
720 | return; | |
721 | ||
722 | -- Generate a check to raise PE if alignment may be inappropriate | |
723 | ||
724 | else | |
8650387e | 725 | -- If the original expression is a non-static constant, use the name |
726 | -- of the constant itself rather than duplicating its initialization | |
727 | -- expression, which was extracted above. | |
0577b0b1 | 728 | |
00c403ee | 729 | -- Note: Expr is empty if the address-clause is applied to in-mode |
730 | -- actuals (allowed by 13.1(22)). | |
731 | ||
732 | if not Present (Expr) | |
733 | or else | |
734 | (Is_Entity_Name (Expression (AC)) | |
735 | and then Ekind (Entity (Expression (AC))) = E_Constant | |
8650387e | 736 | and then Nkind (Parent (Entity (Expression (AC)))) = |
737 | N_Object_Declaration) | |
0577b0b1 | 738 | then |
739 | Expr := New_Copy_Tree (Expression (AC)); | |
740 | else | |
741 | Remove_Side_Effects (Expr); | |
c2b56224 | 742 | end if; |
c2b56224 | 743 | |
d950dc79 | 744 | if No (Actions (N)) then |
745 | Set_Actions (N, New_List); | |
746 | end if; | |
747 | ||
748 | Prepend_To (Actions (N), | |
0577b0b1 | 749 | Make_Raise_Program_Error (Loc, |
750 | Condition => | |
751 | Make_Op_Ne (Loc, | |
8650387e | 752 | Left_Opnd => |
0577b0b1 | 753 | Make_Op_Mod (Loc, |
8650387e | 754 | Left_Opnd => |
0577b0b1 | 755 | Unchecked_Convert_To |
756 | (RTE (RE_Integer_Address), Expr), | |
757 | Right_Opnd => | |
758 | Make_Attribute_Reference (Loc, | |
d950dc79 | 759 | Prefix => New_Occurrence_Of (E, Loc), |
0577b0b1 | 760 | Attribute_Name => Name_Alignment)), |
761 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
8650387e | 762 | Reason => PE_Misaligned_Address_Value)); |
7b8fa048 | 763 | |
764 | Warning_Msg := No_Error_Msg; | |
d950dc79 | 765 | Analyze (First (Actions (N)), Suppress => All_Checks); |
cd309f05 | 766 | |
514a5555 | 767 | -- If the above raise action generated a warning message (for example |
7b8fa048 | 768 | -- from Warn_On_Non_Local_Exception mode with the active restriction |
769 | -- No_Exception_Propagation). | |
770 | ||
771 | if Warning_Msg /= No_Error_Msg then | |
8650387e | 772 | |
7b8fa048 | 773 | -- If the expression has a known at compile time value, then |
774 | -- once we know the alignment of the type, we can check if the | |
775 | -- exception will be raised or not, and if not, we don't need | |
776 | -- the warning so we will kill the warning later on. | |
777 | ||
778 | if Compile_Time_Known_Value (Expr) then | |
779 | Alignment_Warnings.Append | |
780 | ((E => E, A => Expr_Value (Expr), W => Warning_Msg)); | |
cd309f05 | 781 | |
8650387e | 782 | -- Add explanation of the warning generated by the check |
783 | ||
784 | else | |
514a5555 | 785 | Error_Msg_N |
8650387e | 786 | ("\address value may be incompatible with alignment of " |
787 | & "object?X?", AC); | |
514a5555 | 788 | end if; |
cd309f05 | 789 | end if; |
78be29d1 | 790 | |
0577b0b1 | 791 | return; |
792 | end if; | |
9dfe12ae | 793 | |
794 | exception | |
8650387e | 795 | |
0577b0b1 | 796 | -- If we have some missing run time component in configurable run time |
797 | -- mode then just skip the check (it is not required in any case). | |
798 | ||
9dfe12ae | 799 | when RE_Not_Available => |
800 | return; | |
0577b0b1 | 801 | end Apply_Address_Clause_Check; |
c2b56224 | 802 | |
ee6ba406 | 803 | ------------------------------------- |
804 | -- Apply_Arithmetic_Overflow_Check -- | |
805 | ------------------------------------- | |
806 | ||
3cce7f32 | 807 | procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is |
808 | begin | |
809 | -- Use old routine in almost all cases (the only case we are treating | |
21a55437 | 810 | -- specially is the case of a signed integer arithmetic op with the |
0df9d43f | 811 | -- overflow checking mode set to MINIMIZED or ELIMINATED). |
3cce7f32 | 812 | |
0df9d43f | 813 | if Overflow_Check_Mode = Strict |
3cce7f32 | 814 | or else not Is_Signed_Integer_Arithmetic_Op (N) |
815 | then | |
0df9d43f | 816 | Apply_Arithmetic_Overflow_Strict (N); |
3cce7f32 | 817 | |
21a55437 | 818 | -- Otherwise use the new routine for the case of a signed integer |
819 | -- arithmetic op, with Do_Overflow_Check set to True, and the checking | |
820 | -- mode is MINIMIZED or ELIMINATED. | |
3cce7f32 | 821 | |
822 | else | |
823 | Apply_Arithmetic_Overflow_Minimized_Eliminated (N); | |
824 | end if; | |
825 | end Apply_Arithmetic_Overflow_Check; | |
826 | ||
0df9d43f | 827 | -------------------------------------- |
828 | -- Apply_Arithmetic_Overflow_Strict -- | |
829 | -------------------------------------- | |
3cce7f32 | 830 | |
fc1dbe36 | 831 | -- This routine is called only if the type is an integer type and an |
832 | -- arithmetic overflow check may be needed for op (add, subtract, or | |
833 | -- multiply). This check is performed if Backend_Overflow_Checks_On_Target | |
834 | -- is not enabled and Do_Overflow_Check is set. In this case we expand the | |
f40f9731 | 835 | -- operation into a more complex sequence of tests that ensures that |
836 | -- overflow is properly caught. | |
ee6ba406 | 837 | |
0df9d43f | 838 | -- This is used in CHECKED modes. It is identical to the code for this |
839 | -- cases before the big overflow earthquake, thus ensuring that in this | |
840 | -- modes we have compatible behavior (and reliability) to what was there | |
841 | -- before. It is also called for types other than signed integers, and if | |
842 | -- the Do_Overflow_Check flag is off. | |
3cce7f32 | 843 | |
844 | -- Note: we also call this routine if we decide in the MINIMIZED case | |
845 | -- to give up and just generate an overflow check without any fuss. | |
846 | ||
0df9d43f | 847 | procedure Apply_Arithmetic_Overflow_Strict (N : Node_Id) is |
21a55437 | 848 | Loc : constant Source_Ptr := Sloc (N); |
849 | Typ : constant Entity_Id := Etype (N); | |
850 | Rtyp : constant Entity_Id := Root_Type (Typ); | |
ee6ba406 | 851 | |
852 | begin | |
0df9d43f | 853 | -- Nothing to do if Do_Overflow_Check not set or overflow checks |
854 | -- suppressed. | |
855 | ||
856 | if not Do_Overflow_Check (N) then | |
857 | return; | |
858 | end if; | |
859 | ||
f40f9731 | 860 | -- An interesting special case. If the arithmetic operation appears as |
861 | -- the operand of a type conversion: | |
862 | ||
863 | -- type1 (x op y) | |
864 | ||
865 | -- and all the following conditions apply: | |
866 | ||
867 | -- arithmetic operation is for a signed integer type | |
868 | -- target type type1 is a static integer subtype | |
869 | -- range of x and y are both included in the range of type1 | |
870 | -- range of x op y is included in the range of type1 | |
871 | -- size of type1 is at least twice the result size of op | |
872 | ||
a36d34e4 | 873 | -- then we don't do an overflow check in any case. Instead, we transform |
f40f9731 | 874 | -- the operation so that we end up with: |
875 | ||
876 | -- type1 (type1 (x) op type1 (y)) | |
877 | ||
878 | -- This avoids intermediate overflow before the conversion. It is | |
879 | -- explicitly permitted by RM 3.5.4(24): | |
880 | ||
881 | -- For the execution of a predefined operation of a signed integer | |
882 | -- type, the implementation need not raise Constraint_Error if the | |
883 | -- result is outside the base range of the type, so long as the | |
884 | -- correct result is produced. | |
885 | ||
886 | -- It's hard to imagine that any programmer counts on the exception | |
887 | -- being raised in this case, and in any case it's wrong coding to | |
888 | -- have this expectation, given the RM permission. Furthermore, other | |
889 | -- Ada compilers do allow such out of range results. | |
890 | ||
891 | -- Note that we do this transformation even if overflow checking is | |
892 | -- off, since this is precisely about giving the "right" result and | |
893 | -- avoiding the need for an overflow check. | |
894 | ||
8eb4a5eb | 895 | -- Note: this circuit is partially redundant with respect to the similar |
896 | -- processing in Exp_Ch4.Expand_N_Type_Conversion, but the latter deals | |
897 | -- with cases that do not come through here. We still need the following | |
898 | -- processing even with the Exp_Ch4 code in place, since we want to be | |
899 | -- sure not to generate the arithmetic overflow check in these cases | |
900 | -- (Exp_Ch4 would have a hard time removing them once generated). | |
901 | ||
f40f9731 | 902 | if Is_Signed_Integer_Type (Typ) |
903 | and then Nkind (Parent (N)) = N_Type_Conversion | |
ee6ba406 | 904 | then |
f32c377d | 905 | Conversion_Optimization : declare |
f40f9731 | 906 | Target_Type : constant Entity_Id := |
b6341c67 | 907 | Base_Type (Entity (Subtype_Mark (Parent (N)))); |
f40f9731 | 908 | |
909 | Llo, Lhi : Uint; | |
910 | Rlo, Rhi : Uint; | |
911 | LOK, ROK : Boolean; | |
912 | ||
913 | Vlo : Uint; | |
914 | Vhi : Uint; | |
915 | VOK : Boolean; | |
916 | ||
917 | Tlo : Uint; | |
918 | Thi : Uint; | |
919 | ||
920 | begin | |
921 | if Is_Integer_Type (Target_Type) | |
922 | and then RM_Size (Root_Type (Target_Type)) >= 2 * RM_Size (Rtyp) | |
923 | then | |
924 | Tlo := Expr_Value (Type_Low_Bound (Target_Type)); | |
925 | Thi := Expr_Value (Type_High_Bound (Target_Type)); | |
926 | ||
9c486805 | 927 | Determine_Range |
928 | (Left_Opnd (N), LOK, Llo, Lhi, Assume_Valid => True); | |
929 | Determine_Range | |
930 | (Right_Opnd (N), ROK, Rlo, Rhi, Assume_Valid => True); | |
f40f9731 | 931 | |
932 | if (LOK and ROK) | |
933 | and then Tlo <= Llo and then Lhi <= Thi | |
934 | and then Tlo <= Rlo and then Rhi <= Thi | |
935 | then | |
9c486805 | 936 | Determine_Range (N, VOK, Vlo, Vhi, Assume_Valid => True); |
f40f9731 | 937 | |
938 | if VOK and then Tlo <= Vlo and then Vhi <= Thi then | |
939 | Rewrite (Left_Opnd (N), | |
940 | Make_Type_Conversion (Loc, | |
941 | Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), | |
942 | Expression => Relocate_Node (Left_Opnd (N)))); | |
943 | ||
944 | Rewrite (Right_Opnd (N), | |
945 | Make_Type_Conversion (Loc, | |
946 | Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), | |
947 | Expression => Relocate_Node (Right_Opnd (N)))); | |
948 | ||
780bfb21 | 949 | -- Rewrite the conversion operand so that the original |
950 | -- node is retained, in order to avoid the warning for | |
951 | -- redundant conversions in Resolve_Type_Conversion. | |
952 | ||
953 | Rewrite (N, Relocate_Node (N)); | |
954 | ||
f40f9731 | 955 | Set_Etype (N, Target_Type); |
780bfb21 | 956 | |
f40f9731 | 957 | Analyze_And_Resolve (Left_Opnd (N), Target_Type); |
958 | Analyze_And_Resolve (Right_Opnd (N), Target_Type); | |
959 | ||
960 | -- Given that the target type is twice the size of the | |
961 | -- source type, overflow is now impossible, so we can | |
962 | -- safely kill the overflow check and return. | |
963 | ||
964 | Set_Do_Overflow_Check (N, False); | |
965 | return; | |
966 | end if; | |
967 | end if; | |
968 | end if; | |
f32c377d | 969 | end Conversion_Optimization; |
ee6ba406 | 970 | end if; |
971 | ||
f40f9731 | 972 | -- Now see if an overflow check is required |
973 | ||
974 | declare | |
975 | Siz : constant Int := UI_To_Int (Esize (Rtyp)); | |
976 | Dsiz : constant Int := Siz * 2; | |
977 | Opnod : Node_Id; | |
978 | Ctyp : Entity_Id; | |
979 | Opnd : Node_Id; | |
980 | Cent : RE_Id; | |
ee6ba406 | 981 | |
f40f9731 | 982 | begin |
983 | -- Skip check if back end does overflow checks, or the overflow flag | |
df40eeb0 | 984 | -- is not set anyway, or we are not doing code expansion, or the |
985 | -- parent node is a type conversion whose operand is an arithmetic | |
986 | -- operation on signed integers on which the expander can promote | |
bbbed24b | 987 | -- later the operands to type Integer (see Expand_N_Type_Conversion). |
ee6ba406 | 988 | |
f40f9731 | 989 | if Backend_Overflow_Checks_On_Target |
990 | or else not Do_Overflow_Check (N) | |
a33565dd | 991 | or else not Expander_Active |
df40eeb0 | 992 | or else (Present (Parent (N)) |
993 | and then Nkind (Parent (N)) = N_Type_Conversion | |
994 | and then Integer_Promotion_Possible (Parent (N))) | |
f40f9731 | 995 | then |
996 | return; | |
997 | end if; | |
ee6ba406 | 998 | |
f40f9731 | 999 | -- Otherwise, generate the full general code for front end overflow |
1000 | -- detection, which works by doing arithmetic in a larger type: | |
ee6ba406 | 1001 | |
f40f9731 | 1002 | -- x op y |
ee6ba406 | 1003 | |
f40f9731 | 1004 | -- is expanded into |
ee6ba406 | 1005 | |
f40f9731 | 1006 | -- Typ (Checktyp (x) op Checktyp (y)); |
ee6ba406 | 1007 | |
f40f9731 | 1008 | -- where Typ is the type of the original expression, and Checktyp is |
1009 | -- an integer type of sufficient length to hold the largest possible | |
1010 | -- result. | |
ee6ba406 | 1011 | |
f40f9731 | 1012 | -- If the size of check type exceeds the size of Long_Long_Integer, |
1013 | -- we use a different approach, expanding to: | |
ee6ba406 | 1014 | |
f40f9731 | 1015 | -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y))) |
ee6ba406 | 1016 | |
f40f9731 | 1017 | -- where xxx is Add, Multiply or Subtract as appropriate |
ee6ba406 | 1018 | |
f40f9731 | 1019 | -- Find check type if one exists |
1020 | ||
1021 | if Dsiz <= Standard_Integer_Size then | |
1022 | Ctyp := Standard_Integer; | |
ee6ba406 | 1023 | |
f40f9731 | 1024 | elsif Dsiz <= Standard_Long_Long_Integer_Size then |
1025 | Ctyp := Standard_Long_Long_Integer; | |
1026 | ||
c9f84db7 | 1027 | -- No check type exists, use runtime call |
ee6ba406 | 1028 | |
1029 | else | |
f40f9731 | 1030 | if Nkind (N) = N_Op_Add then |
1031 | Cent := RE_Add_With_Ovflo_Check; | |
ee6ba406 | 1032 | |
f40f9731 | 1033 | elsif Nkind (N) = N_Op_Multiply then |
1034 | Cent := RE_Multiply_With_Ovflo_Check; | |
ee6ba406 | 1035 | |
f40f9731 | 1036 | else |
1037 | pragma Assert (Nkind (N) = N_Op_Subtract); | |
1038 | Cent := RE_Subtract_With_Ovflo_Check; | |
1039 | end if; | |
1040 | ||
1041 | Rewrite (N, | |
1042 | OK_Convert_To (Typ, | |
1043 | Make_Function_Call (Loc, | |
83c6c069 | 1044 | Name => New_Occurrence_Of (RTE (Cent), Loc), |
f40f9731 | 1045 | Parameter_Associations => New_List ( |
1046 | OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)), | |
1047 | OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N)))))); | |
ee6ba406 | 1048 | |
f40f9731 | 1049 | Analyze_And_Resolve (N, Typ); |
1050 | return; | |
1051 | end if; | |
ee6ba406 | 1052 | |
f40f9731 | 1053 | -- If we fall through, we have the case where we do the arithmetic |
1054 | -- in the next higher type and get the check by conversion. In these | |
1055 | -- cases Ctyp is set to the type to be used as the check type. | |
ee6ba406 | 1056 | |
f40f9731 | 1057 | Opnod := Relocate_Node (N); |
ee6ba406 | 1058 | |
f40f9731 | 1059 | Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod)); |
ee6ba406 | 1060 | |
f40f9731 | 1061 | Analyze (Opnd); |
1062 | Set_Etype (Opnd, Ctyp); | |
1063 | Set_Analyzed (Opnd, True); | |
1064 | Set_Left_Opnd (Opnod, Opnd); | |
ee6ba406 | 1065 | |
f40f9731 | 1066 | Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod)); |
ee6ba406 | 1067 | |
f40f9731 | 1068 | Analyze (Opnd); |
1069 | Set_Etype (Opnd, Ctyp); | |
1070 | Set_Analyzed (Opnd, True); | |
1071 | Set_Right_Opnd (Opnod, Opnd); | |
ee6ba406 | 1072 | |
f40f9731 | 1073 | -- The type of the operation changes to the base type of the check |
1074 | -- type, and we reset the overflow check indication, since clearly no | |
1075 | -- overflow is possible now that we are using a double length type. | |
1076 | -- We also set the Analyzed flag to avoid a recursive attempt to | |
1077 | -- expand the node. | |
ee6ba406 | 1078 | |
f40f9731 | 1079 | Set_Etype (Opnod, Base_Type (Ctyp)); |
1080 | Set_Do_Overflow_Check (Opnod, False); | |
1081 | Set_Analyzed (Opnod, True); | |
ee6ba406 | 1082 | |
f40f9731 | 1083 | -- Now build the outer conversion |
ee6ba406 | 1084 | |
f40f9731 | 1085 | Opnd := OK_Convert_To (Typ, Opnod); |
1086 | Analyze (Opnd); | |
1087 | Set_Etype (Opnd, Typ); | |
9dfe12ae | 1088 | |
f40f9731 | 1089 | -- In the discrete type case, we directly generate the range check |
1090 | -- for the outer operand. This range check will implement the | |
1091 | -- required overflow check. | |
9dfe12ae | 1092 | |
f40f9731 | 1093 | if Is_Discrete_Type (Typ) then |
1094 | Rewrite (N, Opnd); | |
1095 | Generate_Range_Check | |
1096 | (Expression (N), Typ, CE_Overflow_Check_Failed); | |
9dfe12ae | 1097 | |
f40f9731 | 1098 | -- For other types, we enable overflow checking on the conversion, |
1099 | -- after setting the node as analyzed to prevent recursive attempts | |
1100 | -- to expand the conversion node. | |
9dfe12ae | 1101 | |
f40f9731 | 1102 | else |
1103 | Set_Analyzed (Opnd, True); | |
1104 | Enable_Overflow_Check (Opnd); | |
1105 | Rewrite (N, Opnd); | |
1106 | end if; | |
1107 | ||
1108 | exception | |
1109 | when RE_Not_Available => | |
1110 | return; | |
1111 | end; | |
0df9d43f | 1112 | end Apply_Arithmetic_Overflow_Strict; |
3cce7f32 | 1113 | |
1114 | ---------------------------------------------------- | |
1115 | -- Apply_Arithmetic_Overflow_Minimized_Eliminated -- | |
1116 | ---------------------------------------------------- | |
1117 | ||
1118 | procedure Apply_Arithmetic_Overflow_Minimized_Eliminated (Op : Node_Id) is | |
1119 | pragma Assert (Is_Signed_Integer_Arithmetic_Op (Op)); | |
3cce7f32 | 1120 | |
1121 | Loc : constant Source_Ptr := Sloc (Op); | |
1122 | P : constant Node_Id := Parent (Op); | |
1123 | ||
49b3a812 | 1124 | LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); |
1125 | -- Operands and results are of this type when we convert | |
1126 | ||
3cce7f32 | 1127 | Result_Type : constant Entity_Id := Etype (Op); |
1128 | -- Original result type | |
1129 | ||
db415383 | 1130 | Check_Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
3cce7f32 | 1131 | pragma Assert (Check_Mode in Minimized_Or_Eliminated); |
1132 | ||
1133 | Lo, Hi : Uint; | |
1134 | -- Ranges of values for result | |
1135 | ||
1136 | begin | |
1137 | -- Nothing to do if our parent is one of the following: | |
1138 | ||
0326b4d4 | 1139 | -- Another signed integer arithmetic op |
3cce7f32 | 1140 | -- A membership operation |
1141 | -- A comparison operation | |
1142 | ||
1143 | -- In all these cases, we will process at the higher level (and then | |
1144 | -- this node will be processed during the downwards recursion that | |
0df9d43f | 1145 | -- is part of the processing in Minimize_Eliminate_Overflows). |
3cce7f32 | 1146 | |
1147 | if Is_Signed_Integer_Arithmetic_Op (P) | |
b8a17a21 | 1148 | or else Nkind (P) in N_Membership_Test |
1149 | or else Nkind (P) in N_Op_Compare | |
aa4b16cb | 1150 | |
70a2dff4 | 1151 | -- This is also true for an alternative in a case expression |
1152 | ||
1153 | or else Nkind (P) = N_Case_Expression_Alternative | |
1154 | ||
1155 | -- This is also true for a range operand in a membership test | |
aa4b16cb | 1156 | |
b8a17a21 | 1157 | or else (Nkind (P) = N_Range |
1158 | and then Nkind (Parent (P)) in N_Membership_Test) | |
3cce7f32 | 1159 | then |
af90720d | 1160 | -- If_Expressions and Case_Expressions are treated as arithmetic |
1161 | -- ops, but if they appear in an assignment or similar contexts | |
1162 | -- there is no overflow check that starts from that parent node, | |
1163 | -- so apply check now. | |
1164 | ||
1165 | if Nkind_In (P, N_If_Expression, N_Case_Expression) | |
1166 | and then not Is_Signed_Integer_Arithmetic_Op (Parent (P)) | |
1167 | then | |
1168 | null; | |
1169 | else | |
1170 | return; | |
1171 | end if; | |
3cce7f32 | 1172 | end if; |
1173 | ||
0326b4d4 | 1174 | -- Otherwise, we have a top level arithmetic operation node, and this |
21a55437 | 1175 | -- is where we commence the special processing for MINIMIZED/ELIMINATED |
1176 | -- modes. This is the case where we tell the machinery not to move into | |
1177 | -- Bignum mode at this top level (of course the top level operation | |
1178 | -- will still be in Bignum mode if either of its operands are of type | |
1179 | -- Bignum). | |
3cce7f32 | 1180 | |
0df9d43f | 1181 | Minimize_Eliminate_Overflows (Op, Lo, Hi, Top_Level => True); |
3cce7f32 | 1182 | |
1183 | -- That call may but does not necessarily change the result type of Op. | |
1184 | -- It is the job of this routine to undo such changes, so that at the | |
1185 | -- top level, we have the proper type. This "undoing" is a point at | |
1186 | -- which a final overflow check may be applied. | |
1187 | ||
f32c377d | 1188 | -- If the result type was not fiddled we are all set. We go to base |
1189 | -- types here because things may have been rewritten to generate the | |
1190 | -- base type of the operand types. | |
3cce7f32 | 1191 | |
f32c377d | 1192 | if Base_Type (Etype (Op)) = Base_Type (Result_Type) then |
3cce7f32 | 1193 | return; |
1194 | ||
1195 | -- Bignum case | |
1196 | ||
49b3a812 | 1197 | elsif Is_RTE (Etype (Op), RE_Bignum) then |
3cce7f32 | 1198 | |
d94b5da2 | 1199 | -- We need a sequence that looks like: |
3cce7f32 | 1200 | |
1201 | -- Rnn : Result_Type; | |
1202 | ||
1203 | -- declare | |
d94b5da2 | 1204 | -- M : Mark_Id := SS_Mark; |
3cce7f32 | 1205 | -- begin |
49b3a812 | 1206 | -- Rnn := Long_Long_Integer'Base (From_Bignum (Op)); |
3cce7f32 | 1207 | -- SS_Release (M); |
1208 | -- end; | |
1209 | ||
1210 | -- This block is inserted (using Insert_Actions), and then the node | |
1211 | -- is replaced with a reference to Rnn. | |
1212 | ||
75b45a21 | 1213 | -- If our parent is a conversion node then there is no point in |
a36d34e4 | 1214 | -- generating a conversion to Result_Type. Instead, we let the parent |
75b45a21 | 1215 | -- handle this. Note that this special case is not just about |
1216 | -- optimization. Consider | |
3cce7f32 | 1217 | |
1218 | -- A,B,C : Integer; | |
1219 | -- ... | |
49b3a812 | 1220 | -- X := Long_Long_Integer'Base (A * (B ** C)); |
3cce7f32 | 1221 | |
1222 | -- Now the product may fit in Long_Long_Integer but not in Integer. | |
21a55437 | 1223 | -- In MINIMIZED/ELIMINATED mode, we don't want to introduce an |
1224 | -- overflow exception for this intermediate value. | |
3cce7f32 | 1225 | |
1226 | declare | |
49b3a812 | 1227 | Blk : constant Node_Id := Make_Bignum_Block (Loc); |
3cce7f32 | 1228 | Rnn : constant Entity_Id := Make_Temporary (Loc, 'R', Op); |
1229 | RHS : Node_Id; | |
1230 | ||
1231 | Rtype : Entity_Id; | |
1232 | ||
1233 | begin | |
1234 | RHS := Convert_From_Bignum (Op); | |
1235 | ||
1236 | if Nkind (P) /= N_Type_Conversion then | |
49b3a812 | 1237 | Convert_To_And_Rewrite (Result_Type, RHS); |
3cce7f32 | 1238 | Rtype := Result_Type; |
1239 | ||
1240 | -- Interesting question, do we need a check on that conversion | |
1241 | -- operation. Answer, not if we know the result is in range. | |
1242 | -- At the moment we are not taking advantage of this. To be | |
1243 | -- looked at later ??? | |
1244 | ||
1245 | else | |
49b3a812 | 1246 | Rtype := LLIB; |
3cce7f32 | 1247 | end if; |
1248 | ||
1249 | Insert_Before | |
1250 | (First (Statements (Handled_Statement_Sequence (Blk))), | |
1251 | Make_Assignment_Statement (Loc, | |
1252 | Name => New_Occurrence_Of (Rnn, Loc), | |
1253 | Expression => RHS)); | |
1254 | ||
1255 | Insert_Actions (Op, New_List ( | |
1256 | Make_Object_Declaration (Loc, | |
1257 | Defining_Identifier => Rnn, | |
1258 | Object_Definition => New_Occurrence_Of (Rtype, Loc)), | |
1259 | Blk)); | |
1260 | ||
1261 | Rewrite (Op, New_Occurrence_Of (Rnn, Loc)); | |
1262 | Analyze_And_Resolve (Op); | |
1263 | end; | |
1264 | ||
af90720d | 1265 | -- Here we know the result is Long_Long_Integer'Base, or that it has |
412f75eb | 1266 | -- been rewritten because the parent operation is a conversion. See |
0df9d43f | 1267 | -- Apply_Arithmetic_Overflow_Strict.Conversion_Optimization. |
3cce7f32 | 1268 | |
1269 | else | |
f32c377d | 1270 | pragma Assert |
1271 | (Etype (Op) = LLIB or else Nkind (Parent (Op)) = N_Type_Conversion); | |
3cce7f32 | 1272 | |
1273 | -- All we need to do here is to convert the result to the proper | |
1274 | -- result type. As explained above for the Bignum case, we can | |
1275 | -- omit this if our parent is a type conversion. | |
1276 | ||
1277 | if Nkind (P) /= N_Type_Conversion then | |
1278 | Convert_To_And_Rewrite (Result_Type, Op); | |
1279 | end if; | |
1280 | ||
1281 | Analyze_And_Resolve (Op); | |
1282 | end if; | |
1283 | end Apply_Arithmetic_Overflow_Minimized_Eliminated; | |
ee6ba406 | 1284 | |
ee6ba406 | 1285 | ---------------------------- |
1286 | -- Apply_Constraint_Check -- | |
1287 | ---------------------------- | |
1288 | ||
1289 | procedure Apply_Constraint_Check | |
1290 | (N : Node_Id; | |
1291 | Typ : Entity_Id; | |
1292 | No_Sliding : Boolean := False) | |
1293 | is | |
1294 | Desig_Typ : Entity_Id; | |
1295 | ||
1296 | begin | |
7aafae1c | 1297 | -- No checks inside a generic (check the instantiations) |
1298 | ||
ee6ba406 | 1299 | if Inside_A_Generic then |
1300 | return; | |
7aafae1c | 1301 | end if; |
ee6ba406 | 1302 | |
6fb3c314 | 1303 | -- Apply required constraint checks |
7aafae1c | 1304 | |
1305 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 1306 | Apply_Scalar_Range_Check (N, Typ); |
1307 | ||
1308 | elsif Is_Array_Type (Typ) then | |
1309 | ||
05fcfafb | 1310 | -- A useful optimization: an aggregate with only an others clause |
5f260d20 | 1311 | -- always has the right bounds. |
1312 | ||
1313 | if Nkind (N) = N_Aggregate | |
1314 | and then No (Expressions (N)) | |
1315 | and then Nkind | |
1316 | (First (Choices (First (Component_Associations (N))))) | |
1317 | = N_Others_Choice | |
1318 | then | |
1319 | return; | |
1320 | end if; | |
1321 | ||
ee6ba406 | 1322 | if Is_Constrained (Typ) then |
1323 | Apply_Length_Check (N, Typ); | |
1324 | ||
1325 | if No_Sliding then | |
1326 | Apply_Range_Check (N, Typ); | |
1327 | end if; | |
1328 | else | |
1329 | Apply_Range_Check (N, Typ); | |
1330 | end if; | |
1331 | ||
4fb5f0a0 | 1332 | elsif (Is_Record_Type (Typ) or else Is_Private_Type (Typ)) |
ee6ba406 | 1333 | and then Has_Discriminants (Base_Type (Typ)) |
1334 | and then Is_Constrained (Typ) | |
1335 | then | |
1336 | Apply_Discriminant_Check (N, Typ); | |
1337 | ||
1338 | elsif Is_Access_Type (Typ) then | |
1339 | ||
1340 | Desig_Typ := Designated_Type (Typ); | |
1341 | ||
1342 | -- No checks necessary if expression statically null | |
1343 | ||
2af58f67 | 1344 | if Known_Null (N) then |
00c403ee | 1345 | if Can_Never_Be_Null (Typ) then |
1346 | Install_Null_Excluding_Check (N); | |
1347 | end if; | |
ee6ba406 | 1348 | |
1349 | -- No sliding possible on access to arrays | |
1350 | ||
1351 | elsif Is_Array_Type (Desig_Typ) then | |
1352 | if Is_Constrained (Desig_Typ) then | |
1353 | Apply_Length_Check (N, Typ); | |
1354 | end if; | |
1355 | ||
1356 | Apply_Range_Check (N, Typ); | |
1357 | ||
a63a0aad | 1358 | -- Do not install a discriminant check for a constrained subtype |
1359 | -- created for an unconstrained nominal type because the subtype | |
1360 | -- has the correct constraints by construction. | |
1361 | ||
ee6ba406 | 1362 | elsif Has_Discriminants (Base_Type (Desig_Typ)) |
a63a0aad | 1363 | and then Is_Constrained (Desig_Typ) |
1364 | and then not Is_Constr_Subt_For_U_Nominal (Desig_Typ) | |
ee6ba406 | 1365 | then |
1366 | Apply_Discriminant_Check (N, Typ); | |
1367 | end if; | |
fa7497e8 | 1368 | |
bf3e1520 | 1369 | -- Apply the 2005 Null_Excluding check. Note that we do not apply |
00c403ee | 1370 | -- this check if the constraint node is illegal, as shown by having |
1371 | -- an error posted. This additional guard prevents cascaded errors | |
1372 | -- and compiler aborts on illegal programs involving Ada 2005 checks. | |
1373 | ||
fa7497e8 | 1374 | if Can_Never_Be_Null (Typ) |
1375 | and then not Can_Never_Be_Null (Etype (N)) | |
00c403ee | 1376 | and then not Error_Posted (N) |
fa7497e8 | 1377 | then |
1378 | Install_Null_Excluding_Check (N); | |
1379 | end if; | |
ee6ba406 | 1380 | end if; |
1381 | end Apply_Constraint_Check; | |
1382 | ||
1383 | ------------------------------ | |
1384 | -- Apply_Discriminant_Check -- | |
1385 | ------------------------------ | |
1386 | ||
1387 | procedure Apply_Discriminant_Check | |
1388 | (N : Node_Id; | |
1389 | Typ : Entity_Id; | |
1390 | Lhs : Node_Id := Empty) | |
1391 | is | |
1392 | Loc : constant Source_Ptr := Sloc (N); | |
1393 | Do_Access : constant Boolean := Is_Access_Type (Typ); | |
1394 | S_Typ : Entity_Id := Etype (N); | |
1395 | Cond : Node_Id; | |
1396 | T_Typ : Entity_Id; | |
1397 | ||
7be5088a | 1398 | function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean; |
1399 | -- A heap object with an indefinite subtype is constrained by its | |
1400 | -- initial value, and assigning to it requires a constraint_check. | |
1401 | -- The target may be an explicit dereference, or a renaming of one. | |
1402 | ||
ee6ba406 | 1403 | function Is_Aliased_Unconstrained_Component return Boolean; |
1404 | -- It is possible for an aliased component to have a nominal | |
1405 | -- unconstrained subtype (through instantiation). If this is a | |
1406 | -- discriminated component assigned in the expansion of an aggregate | |
1407 | -- in an initialization, the check must be suppressed. This unusual | |
2af58f67 | 1408 | -- situation requires a predicate of its own. |
ee6ba406 | 1409 | |
7be5088a | 1410 | ---------------------------------- |
1411 | -- Denotes_Explicit_Dereference -- | |
1412 | ---------------------------------- | |
1413 | ||
1414 | function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean is | |
1415 | begin | |
1416 | return | |
1417 | Nkind (Obj) = N_Explicit_Dereference | |
1418 | or else | |
1419 | (Is_Entity_Name (Obj) | |
1420 | and then Present (Renamed_Object (Entity (Obj))) | |
9474aa9c | 1421 | and then Nkind (Renamed_Object (Entity (Obj))) = |
1422 | N_Explicit_Dereference); | |
7be5088a | 1423 | end Denotes_Explicit_Dereference; |
1424 | ||
ee6ba406 | 1425 | ---------------------------------------- |
1426 | -- Is_Aliased_Unconstrained_Component -- | |
1427 | ---------------------------------------- | |
1428 | ||
1429 | function Is_Aliased_Unconstrained_Component return Boolean is | |
1430 | Comp : Entity_Id; | |
1431 | Pref : Node_Id; | |
1432 | ||
1433 | begin | |
1434 | if Nkind (Lhs) /= N_Selected_Component then | |
1435 | return False; | |
1436 | else | |
1437 | Comp := Entity (Selector_Name (Lhs)); | |
1438 | Pref := Prefix (Lhs); | |
1439 | end if; | |
1440 | ||
1441 | if Ekind (Comp) /= E_Component | |
1442 | or else not Is_Aliased (Comp) | |
1443 | then | |
1444 | return False; | |
1445 | end if; | |
1446 | ||
1447 | return not Comes_From_Source (Pref) | |
1448 | and then In_Instance | |
1449 | and then not Is_Constrained (Etype (Comp)); | |
1450 | end Is_Aliased_Unconstrained_Component; | |
1451 | ||
1452 | -- Start of processing for Apply_Discriminant_Check | |
1453 | ||
1454 | begin | |
1455 | if Do_Access then | |
1456 | T_Typ := Designated_Type (Typ); | |
1457 | else | |
1458 | T_Typ := Typ; | |
1459 | end if; | |
1460 | ||
f0d65dae | 1461 | -- Only apply checks when generating code and discriminant checks are |
1462 | -- not suppressed. In GNATprove mode, we do not apply the checks, but we | |
1463 | -- still analyze the expression to possibly issue errors on SPARK code | |
1464 | -- when a run-time error can be detected at compile time. | |
1465 | ||
1466 | if not GNATprove_Mode then | |
1467 | if not Expander_Active | |
1468 | or else Discriminant_Checks_Suppressed (T_Typ) | |
1469 | then | |
1470 | return; | |
1471 | end if; | |
ee6ba406 | 1472 | end if; |
1473 | ||
feff2f05 | 1474 | -- No discriminant checks necessary for an access when expression is |
1475 | -- statically Null. This is not only an optimization, it is fundamental | |
1476 | -- because otherwise discriminant checks may be generated in init procs | |
1477 | -- for types containing an access to a not-yet-frozen record, causing a | |
1478 | -- deadly forward reference. | |
ee6ba406 | 1479 | |
feff2f05 | 1480 | -- Also, if the expression is of an access type whose designated type is |
1481 | -- incomplete, then the access value must be null and we suppress the | |
1482 | -- check. | |
ee6ba406 | 1483 | |
2af58f67 | 1484 | if Known_Null (N) then |
ee6ba406 | 1485 | return; |
1486 | ||
1487 | elsif Is_Access_Type (S_Typ) then | |
1488 | S_Typ := Designated_Type (S_Typ); | |
1489 | ||
1490 | if Ekind (S_Typ) = E_Incomplete_Type then | |
1491 | return; | |
1492 | end if; | |
1493 | end if; | |
1494 | ||
0577b0b1 | 1495 | -- If an assignment target is present, then we need to generate the |
1496 | -- actual subtype if the target is a parameter or aliased object with | |
1497 | -- an unconstrained nominal subtype. | |
1498 | ||
1499 | -- Ada 2005 (AI-363): For Ada 2005, we limit the building of the actual | |
1500 | -- subtype to the parameter and dereference cases, since other aliased | |
1501 | -- objects are unconstrained (unless the nominal subtype is explicitly | |
7be5088a | 1502 | -- constrained). |
ee6ba406 | 1503 | |
1504 | if Present (Lhs) | |
1505 | and then (Present (Param_Entity (Lhs)) | |
de54c5ab | 1506 | or else (Ada_Version < Ada_2005 |
0577b0b1 | 1507 | and then not Is_Constrained (T_Typ) |
ee6ba406 | 1508 | and then Is_Aliased_View (Lhs) |
0577b0b1 | 1509 | and then not Is_Aliased_Unconstrained_Component) |
de54c5ab | 1510 | or else (Ada_Version >= Ada_2005 |
0577b0b1 | 1511 | and then not Is_Constrained (T_Typ) |
7be5088a | 1512 | and then Denotes_Explicit_Dereference (Lhs) |
0577b0b1 | 1513 | and then Nkind (Original_Node (Lhs)) /= |
1514 | N_Function_Call)) | |
ee6ba406 | 1515 | then |
1516 | T_Typ := Get_Actual_Subtype (Lhs); | |
1517 | end if; | |
1518 | ||
feff2f05 | 1519 | -- Nothing to do if the type is unconstrained (this is the case where |
1520 | -- the actual subtype in the RM sense of N is unconstrained and no check | |
1521 | -- is required). | |
ee6ba406 | 1522 | |
1523 | if not Is_Constrained (T_Typ) then | |
1524 | return; | |
05fcfafb | 1525 | |
1526 | -- Ada 2005: nothing to do if the type is one for which there is a | |
1527 | -- partial view that is constrained. | |
1528 | ||
de54c5ab | 1529 | elsif Ada_Version >= Ada_2005 |
0d78d2d4 | 1530 | and then Object_Type_Has_Constrained_Partial_View |
d41a3f41 | 1531 | (Typ => Base_Type (T_Typ), |
1532 | Scop => Current_Scope) | |
05fcfafb | 1533 | then |
1534 | return; | |
ee6ba406 | 1535 | end if; |
1536 | ||
00f91aef | 1537 | -- Nothing to do if the type is an Unchecked_Union |
1538 | ||
1539 | if Is_Unchecked_Union (Base_Type (T_Typ)) then | |
1540 | return; | |
1541 | end if; | |
1542 | ||
8d11916f | 1543 | -- Suppress checks if the subtypes are the same. The check must be |
feff2f05 | 1544 | -- preserved in an assignment to a formal, because the constraint is |
1545 | -- given by the actual. | |
ee6ba406 | 1546 | |
1547 | if Nkind (Original_Node (N)) /= N_Allocator | |
1548 | and then (No (Lhs) | |
8143bf7c | 1549 | or else not Is_Entity_Name (Lhs) |
1550 | or else No (Param_Entity (Lhs))) | |
ee6ba406 | 1551 | then |
1552 | if (Etype (N) = Typ | |
1553 | or else (Do_Access and then Designated_Type (Typ) = S_Typ)) | |
1554 | and then not Is_Aliased_View (Lhs) | |
1555 | then | |
1556 | return; | |
1557 | end if; | |
1558 | ||
feff2f05 | 1559 | -- We can also eliminate checks on allocators with a subtype mark that |
1560 | -- coincides with the context type. The context type may be a subtype | |
1561 | -- without a constraint (common case, a generic actual). | |
ee6ba406 | 1562 | |
1563 | elsif Nkind (Original_Node (N)) = N_Allocator | |
1564 | and then Is_Entity_Name (Expression (Original_Node (N))) | |
1565 | then | |
1566 | declare | |
9dfe12ae | 1567 | Alloc_Typ : constant Entity_Id := |
b6341c67 | 1568 | Entity (Expression (Original_Node (N))); |
ee6ba406 | 1569 | |
1570 | begin | |
1571 | if Alloc_Typ = T_Typ | |
1572 | or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration | |
1573 | and then Is_Entity_Name ( | |
1574 | Subtype_Indication (Parent (T_Typ))) | |
1575 | and then Alloc_Typ = Base_Type (T_Typ)) | |
1576 | ||
1577 | then | |
1578 | return; | |
1579 | end if; | |
1580 | end; | |
1581 | end if; | |
1582 | ||
feff2f05 | 1583 | -- See if we have a case where the types are both constrained, and all |
1584 | -- the constraints are constants. In this case, we can do the check | |
1585 | -- successfully at compile time. | |
ee6ba406 | 1586 | |
8d11916f | 1587 | -- We skip this check for the case where the node is rewritten as |
d7ec9a29 | 1588 | -- an allocator, because it already carries the context subtype, |
1589 | -- and extracting the discriminants from the aggregate is messy. | |
ee6ba406 | 1590 | |
1591 | if Is_Constrained (S_Typ) | |
1592 | and then Nkind (Original_Node (N)) /= N_Allocator | |
1593 | then | |
1594 | declare | |
1595 | DconT : Elmt_Id; | |
1596 | Discr : Entity_Id; | |
1597 | DconS : Elmt_Id; | |
1598 | ItemS : Node_Id; | |
1599 | ItemT : Node_Id; | |
1600 | ||
1601 | begin | |
1602 | -- S_Typ may not have discriminants in the case where it is a | |
feff2f05 | 1603 | -- private type completed by a default discriminated type. In that |
8d11916f | 1604 | -- case, we need to get the constraints from the underlying type. |
feff2f05 | 1605 | -- If the underlying type is unconstrained (i.e. has no default |
1606 | -- discriminants) no check is needed. | |
ee6ba406 | 1607 | |
1608 | if Has_Discriminants (S_Typ) then | |
1609 | Discr := First_Discriminant (S_Typ); | |
1610 | DconS := First_Elmt (Discriminant_Constraint (S_Typ)); | |
1611 | ||
1612 | else | |
1613 | Discr := First_Discriminant (Underlying_Type (S_Typ)); | |
1614 | DconS := | |
1615 | First_Elmt | |
1616 | (Discriminant_Constraint (Underlying_Type (S_Typ))); | |
1617 | ||
1618 | if No (DconS) then | |
1619 | return; | |
1620 | end if; | |
fccb5da7 | 1621 | |
1622 | -- A further optimization: if T_Typ is derived from S_Typ | |
1623 | -- without imposing a constraint, no check is needed. | |
1624 | ||
1625 | if Nkind (Original_Node (Parent (T_Typ))) = | |
1626 | N_Full_Type_Declaration | |
1627 | then | |
1628 | declare | |
5c61a0ff | 1629 | Type_Def : constant Node_Id := |
b6341c67 | 1630 | Type_Definition (Original_Node (Parent (T_Typ))); |
fccb5da7 | 1631 | begin |
1632 | if Nkind (Type_Def) = N_Derived_Type_Definition | |
1633 | and then Is_Entity_Name (Subtype_Indication (Type_Def)) | |
1634 | and then Entity (Subtype_Indication (Type_Def)) = S_Typ | |
1635 | then | |
1636 | return; | |
1637 | end if; | |
1638 | end; | |
1639 | end if; | |
ee6ba406 | 1640 | end if; |
1641 | ||
86594966 | 1642 | -- Constraint may appear in full view of type |
1643 | ||
1644 | if Ekind (T_Typ) = E_Private_Subtype | |
1645 | and then Present (Full_View (T_Typ)) | |
1646 | then | |
d7ec9a29 | 1647 | DconT := |
86594966 | 1648 | First_Elmt (Discriminant_Constraint (Full_View (T_Typ))); |
86594966 | 1649 | else |
d7ec9a29 | 1650 | DconT := |
1651 | First_Elmt (Discriminant_Constraint (T_Typ)); | |
86594966 | 1652 | end if; |
ee6ba406 | 1653 | |
1654 | while Present (Discr) loop | |
1655 | ItemS := Node (DconS); | |
1656 | ItemT := Node (DconT); | |
1657 | ||
00c403ee | 1658 | -- For a discriminated component type constrained by the |
1659 | -- current instance of an enclosing type, there is no | |
1660 | -- applicable discriminant check. | |
1661 | ||
1662 | if Nkind (ItemT) = N_Attribute_Reference | |
1663 | and then Is_Access_Type (Etype (ItemT)) | |
1664 | and then Is_Entity_Name (Prefix (ItemT)) | |
1665 | and then Is_Type (Entity (Prefix (ItemT))) | |
1666 | then | |
1667 | return; | |
1668 | end if; | |
1669 | ||
cc60bd16 | 1670 | -- If the expressions for the discriminants are identical |
1671 | -- and it is side-effect free (for now just an entity), | |
1672 | -- this may be a shared constraint, e.g. from a subtype | |
1673 | -- without a constraint introduced as a generic actual. | |
1674 | -- Examine other discriminants if any. | |
1675 | ||
1676 | if ItemS = ItemT | |
1677 | and then Is_Entity_Name (ItemS) | |
1678 | then | |
1679 | null; | |
1680 | ||
1681 | elsif not Is_OK_Static_Expression (ItemS) | |
1682 | or else not Is_OK_Static_Expression (ItemT) | |
1683 | then | |
1684 | exit; | |
ee6ba406 | 1685 | |
cc60bd16 | 1686 | elsif Expr_Value (ItemS) /= Expr_Value (ItemT) then |
ee6ba406 | 1687 | if Do_Access then -- needs run-time check. |
1688 | exit; | |
1689 | else | |
1690 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 1691 | (N, "incorrect value for discriminant&??", |
f15731c4 | 1692 | CE_Discriminant_Check_Failed, Ent => Discr); |
ee6ba406 | 1693 | return; |
1694 | end if; | |
1695 | end if; | |
1696 | ||
1697 | Next_Elmt (DconS); | |
1698 | Next_Elmt (DconT); | |
1699 | Next_Discriminant (Discr); | |
1700 | end loop; | |
1701 | ||
1702 | if No (Discr) then | |
1703 | return; | |
1704 | end if; | |
1705 | end; | |
1706 | end if; | |
1707 | ||
f0d65dae | 1708 | -- In GNATprove mode, we do not apply the checks |
1709 | ||
1710 | if GNATprove_Mode then | |
1711 | return; | |
1712 | end if; | |
1713 | ||
ee6ba406 | 1714 | -- Here we need a discriminant check. First build the expression |
1715 | -- for the comparisons of the discriminants: | |
1716 | ||
1717 | -- (n.disc1 /= typ.disc1) or else | |
1718 | -- (n.disc2 /= typ.disc2) or else | |
1719 | -- ... | |
1720 | -- (n.discn /= typ.discn) | |
1721 | ||
1722 | Cond := Build_Discriminant_Checks (N, T_Typ); | |
1723 | ||
3cce7f32 | 1724 | -- If Lhs is set and is a parameter, then the condition is guarded by: |
1725 | -- lhs'constrained and then (condition built above) | |
ee6ba406 | 1726 | |
1727 | if Present (Param_Entity (Lhs)) then | |
1728 | Cond := | |
1729 | Make_And_Then (Loc, | |
1730 | Left_Opnd => | |
1731 | Make_Attribute_Reference (Loc, | |
1732 | Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc), | |
1733 | Attribute_Name => Name_Constrained), | |
1734 | Right_Opnd => Cond); | |
1735 | end if; | |
1736 | ||
1737 | if Do_Access then | |
1738 | Cond := Guard_Access (Cond, Loc, N); | |
1739 | end if; | |
1740 | ||
1741 | Insert_Action (N, | |
f15731c4 | 1742 | Make_Raise_Constraint_Error (Loc, |
1743 | Condition => Cond, | |
1744 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 1745 | end Apply_Discriminant_Check; |
1746 | ||
2fe22c69 | 1747 | ------------------------- |
1748 | -- Apply_Divide_Checks -- | |
1749 | ------------------------- | |
ee6ba406 | 1750 | |
2fe22c69 | 1751 | procedure Apply_Divide_Checks (N : Node_Id) is |
ee6ba406 | 1752 | Loc : constant Source_Ptr := Sloc (N); |
1753 | Typ : constant Entity_Id := Etype (N); | |
1754 | Left : constant Node_Id := Left_Opnd (N); | |
1755 | Right : constant Node_Id := Right_Opnd (N); | |
1756 | ||
db415383 | 1757 | Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
2fe22c69 | 1758 | -- Current overflow checking mode |
1759 | ||
ee6ba406 | 1760 | LLB : Uint; |
1761 | Llo : Uint; | |
1762 | Lhi : Uint; | |
1763 | LOK : Boolean; | |
1764 | Rlo : Uint; | |
1765 | Rhi : Uint; | |
2fe22c69 | 1766 | ROK : Boolean; |
96da3284 | 1767 | |
1768 | pragma Warnings (Off, Lhi); | |
1769 | -- Don't actually use this value | |
ee6ba406 | 1770 | |
1771 | begin | |
0df9d43f | 1772 | -- If we are operating in MINIMIZED or ELIMINATED mode, and we are |
1773 | -- operating on signed integer types, then the only thing this routine | |
1774 | -- does is to call Apply_Arithmetic_Overflow_Minimized_Eliminated. That | |
1775 | -- procedure will (possibly later on during recursive downward calls), | |
1776 | -- ensure that any needed overflow/division checks are properly applied. | |
2fe22c69 | 1777 | |
1778 | if Mode in Minimized_Or_Eliminated | |
2fe22c69 | 1779 | and then Is_Signed_Integer_Type (Typ) |
1780 | then | |
1781 | Apply_Arithmetic_Overflow_Minimized_Eliminated (N); | |
1782 | return; | |
1783 | end if; | |
1784 | ||
1785 | -- Proceed here in SUPPRESSED or CHECKED modes | |
1786 | ||
a33565dd | 1787 | if Expander_Active |
13dbf220 | 1788 | and then not Backend_Divide_Checks_On_Target |
1789 | and then Check_Needed (Right, Division_Check) | |
ee6ba406 | 1790 | then |
9c486805 | 1791 | Determine_Range (Right, ROK, Rlo, Rhi, Assume_Valid => True); |
ee6ba406 | 1792 | |
2fe22c69 | 1793 | -- Deal with division check |
ee6ba406 | 1794 | |
2fe22c69 | 1795 | if Do_Division_Check (N) |
1796 | and then not Division_Checks_Suppressed (Typ) | |
1797 | then | |
1798 | Apply_Division_Check (N, Rlo, Rhi, ROK); | |
ee6ba406 | 1799 | end if; |
1800 | ||
2fe22c69 | 1801 | -- Deal with overflow check |
1802 | ||
0df9d43f | 1803 | if Do_Overflow_Check (N) |
1804 | and then not Overflow_Checks_Suppressed (Etype (N)) | |
1805 | then | |
f3ccbbb3 | 1806 | Set_Do_Overflow_Check (N, False); |
1807 | ||
2fe22c69 | 1808 | -- Test for extremely annoying case of xxx'First divided by -1 |
1809 | -- for division of signed integer types (only overflow case). | |
ee6ba406 | 1810 | |
ee6ba406 | 1811 | if Nkind (N) = N_Op_Divide |
1812 | and then Is_Signed_Integer_Type (Typ) | |
1813 | then | |
9c486805 | 1814 | Determine_Range (Left, LOK, Llo, Lhi, Assume_Valid => True); |
ee6ba406 | 1815 | LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ))); |
1816 | ||
1817 | if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) | |
2fe22c69 | 1818 | and then |
1819 | ((not LOK) or else (Llo = LLB)) | |
ee6ba406 | 1820 | then |
f72e7b2a | 1821 | -- Ensure that expressions are not evaluated twice (once |
1822 | -- for their runtime checks and once for their regular | |
1823 | -- computation). | |
1824 | ||
1825 | Force_Evaluation (Left, Mode => Strict); | |
1826 | Force_Evaluation (Right, Mode => Strict); | |
1827 | ||
ee6ba406 | 1828 | Insert_Action (N, |
1829 | Make_Raise_Constraint_Error (Loc, | |
1830 | Condition => | |
1831 | Make_And_Then (Loc, | |
2fe22c69 | 1832 | Left_Opnd => |
1833 | Make_Op_Eq (Loc, | |
1834 | Left_Opnd => | |
1835 | Duplicate_Subexpr_Move_Checks (Left), | |
1836 | Right_Opnd => Make_Integer_Literal (Loc, LLB)), | |
ee6ba406 | 1837 | |
2fe22c69 | 1838 | Right_Opnd => |
1839 | Make_Op_Eq (Loc, | |
1840 | Left_Opnd => Duplicate_Subexpr (Right), | |
1841 | Right_Opnd => Make_Integer_Literal (Loc, -1))), | |
ee6ba406 | 1842 | |
f15731c4 | 1843 | Reason => CE_Overflow_Check_Failed)); |
ee6ba406 | 1844 | end if; |
1845 | end if; | |
1846 | end if; | |
1847 | end if; | |
2fe22c69 | 1848 | end Apply_Divide_Checks; |
1849 | ||
1850 | -------------------------- | |
1851 | -- Apply_Division_Check -- | |
1852 | -------------------------- | |
1853 | ||
1854 | procedure Apply_Division_Check | |
1855 | (N : Node_Id; | |
1856 | Rlo : Uint; | |
1857 | Rhi : Uint; | |
1858 | ROK : Boolean) | |
1859 | is | |
1860 | pragma Assert (Do_Division_Check (N)); | |
1861 | ||
1862 | Loc : constant Source_Ptr := Sloc (N); | |
1863 | Right : constant Node_Id := Right_Opnd (N); | |
1864 | ||
1865 | begin | |
a33565dd | 1866 | if Expander_Active |
2fe22c69 | 1867 | and then not Backend_Divide_Checks_On_Target |
1868 | and then Check_Needed (Right, Division_Check) | |
1869 | then | |
1870 | -- See if division by zero possible, and if so generate test. This | |
1871 | -- part of the test is not controlled by the -gnato switch, since | |
1872 | -- it is a Division_Check and not an Overflow_Check. | |
1873 | ||
1874 | if Do_Division_Check (N) then | |
f3ccbbb3 | 1875 | Set_Do_Division_Check (N, False); |
1876 | ||
2fe22c69 | 1877 | if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then |
1878 | Insert_Action (N, | |
1879 | Make_Raise_Constraint_Error (Loc, | |
1880 | Condition => | |
1881 | Make_Op_Eq (Loc, | |
1882 | Left_Opnd => Duplicate_Subexpr_Move_Checks (Right), | |
1883 | Right_Opnd => Make_Integer_Literal (Loc, 0)), | |
1884 | Reason => CE_Divide_By_Zero)); | |
1885 | end if; | |
1886 | end if; | |
1887 | end if; | |
1888 | end Apply_Division_Check; | |
ee6ba406 | 1889 | |
5329ca64 | 1890 | ---------------------------------- |
1891 | -- Apply_Float_Conversion_Check -- | |
1892 | ---------------------------------- | |
1893 | ||
feff2f05 | 1894 | -- Let F and I be the source and target types of the conversion. The RM |
1895 | -- specifies that a floating-point value X is rounded to the nearest | |
1896 | -- integer, with halfway cases being rounded away from zero. The rounded | |
1897 | -- value of X is checked against I'Range. | |
1898 | ||
1899 | -- The catch in the above paragraph is that there is no good way to know | |
1900 | -- whether the round-to-integer operation resulted in overflow. A remedy is | |
1901 | -- to perform a range check in the floating-point domain instead, however: | |
5329ca64 | 1902 | |
5329ca64 | 1903 | -- (1) The bounds may not be known at compile time |
2af58f67 | 1904 | -- (2) The check must take into account rounding or truncation. |
5329ca64 | 1905 | -- (3) The range of type I may not be exactly representable in F. |
2af58f67 | 1906 | -- (4) For the rounding case, The end-points I'First - 0.5 and |
1907 | -- I'Last + 0.5 may or may not be in range, depending on the | |
1908 | -- sign of I'First and I'Last. | |
5329ca64 | 1909 | -- (5) X may be a NaN, which will fail any comparison |
1910 | ||
2af58f67 | 1911 | -- The following steps correctly convert X with rounding: |
feff2f05 | 1912 | |
5329ca64 | 1913 | -- (1) If either I'First or I'Last is not known at compile time, use |
1914 | -- I'Base instead of I in the next three steps and perform a | |
1915 | -- regular range check against I'Range after conversion. | |
1916 | -- (2) If I'First - 0.5 is representable in F then let Lo be that | |
1917 | -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be | |
2af58f67 | 1918 | -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First). |
1919 | -- In other words, take one of the closest floating-point numbers | |
1920 | -- (which is an integer value) to I'First, and see if it is in | |
1921 | -- range or not. | |
5329ca64 | 1922 | -- (3) If I'Last + 0.5 is representable in F then let Hi be that value |
1923 | -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be | |
2af58f67 | 1924 | -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last). |
5329ca64 | 1925 | -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo) |
1926 | -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi) | |
1927 | ||
2af58f67 | 1928 | -- For the truncating case, replace steps (2) and (3) as follows: |
1929 | -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK | |
1930 | -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let | |
1931 | -- Lo_OK be True. | |
1932 | -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK | |
1933 | -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let | |
141d591a | 1934 | -- Hi_OK be True. |
2af58f67 | 1935 | |
5329ca64 | 1936 | procedure Apply_Float_Conversion_Check |
1937 | (Ck_Node : Node_Id; | |
1938 | Target_Typ : Entity_Id) | |
1939 | is | |
feff2f05 | 1940 | LB : constant Node_Id := Type_Low_Bound (Target_Typ); |
1941 | HB : constant Node_Id := Type_High_Bound (Target_Typ); | |
5329ca64 | 1942 | Loc : constant Source_Ptr := Sloc (Ck_Node); |
1943 | Expr_Type : constant Entity_Id := Base_Type (Etype (Ck_Node)); | |
feff2f05 | 1944 | Target_Base : constant Entity_Id := |
b6341c67 | 1945 | Implementation_Base_Type (Target_Typ); |
feff2f05 | 1946 | |
2af58f67 | 1947 | Par : constant Node_Id := Parent (Ck_Node); |
1948 | pragma Assert (Nkind (Par) = N_Type_Conversion); | |
1949 | -- Parent of check node, must be a type conversion | |
1950 | ||
1951 | Truncate : constant Boolean := Float_Truncate (Par); | |
1952 | Max_Bound : constant Uint := | |
b6341c67 | 1953 | UI_Expon |
1954 | (Machine_Radix_Value (Expr_Type), | |
1955 | Machine_Mantissa_Value (Expr_Type) - 1) - 1; | |
2af58f67 | 1956 | |
5329ca64 | 1957 | -- Largest bound, so bound plus or minus half is a machine number of F |
1958 | ||
feff2f05 | 1959 | Ifirst, Ilast : Uint; |
1960 | -- Bounds of integer type | |
1961 | ||
1962 | Lo, Hi : Ureal; | |
1963 | -- Bounds to check in floating-point domain | |
5329ca64 | 1964 | |
feff2f05 | 1965 | Lo_OK, Hi_OK : Boolean; |
1966 | -- True iff Lo resp. Hi belongs to I'Range | |
5329ca64 | 1967 | |
feff2f05 | 1968 | Lo_Chk, Hi_Chk : Node_Id; |
1969 | -- Expressions that are False iff check fails | |
1970 | ||
1971 | Reason : RT_Exception_Code; | |
5329ca64 | 1972 | |
1973 | begin | |
41f06abf | 1974 | -- We do not need checks if we are not generating code (i.e. the full |
1975 | -- expander is not active). In SPARK mode, we specifically don't want | |
1976 | -- the frontend to expand these checks, which are dealt with directly | |
1977 | -- in the formal verification backend. | |
1978 | ||
a33565dd | 1979 | if not Expander_Active then |
41f06abf | 1980 | return; |
1981 | end if; | |
1982 | ||
5329ca64 | 1983 | if not Compile_Time_Known_Value (LB) |
1984 | or not Compile_Time_Known_Value (HB) | |
1985 | then | |
1986 | declare | |
feff2f05 | 1987 | -- First check that the value falls in the range of the base type, |
1988 | -- to prevent overflow during conversion and then perform a | |
1989 | -- regular range check against the (dynamic) bounds. | |
5329ca64 | 1990 | |
5329ca64 | 1991 | pragma Assert (Target_Base /= Target_Typ); |
5329ca64 | 1992 | |
46eb6933 | 1993 | Temp : constant Entity_Id := Make_Temporary (Loc, 'T', Par); |
5329ca64 | 1994 | |
1995 | begin | |
1996 | Apply_Float_Conversion_Check (Ck_Node, Target_Base); | |
1997 | Set_Etype (Temp, Target_Base); | |
1998 | ||
1999 | Insert_Action (Parent (Par), | |
2000 | Make_Object_Declaration (Loc, | |
2001 | Defining_Identifier => Temp, | |
2002 | Object_Definition => New_Occurrence_Of (Target_Typ, Loc), | |
2003 | Expression => New_Copy_Tree (Par)), | |
2004 | Suppress => All_Checks); | |
2005 | ||
2006 | Insert_Action (Par, | |
2007 | Make_Raise_Constraint_Error (Loc, | |
2008 | Condition => | |
2009 | Make_Not_In (Loc, | |
2010 | Left_Opnd => New_Occurrence_Of (Temp, Loc), | |
2011 | Right_Opnd => New_Occurrence_Of (Target_Typ, Loc)), | |
2012 | Reason => CE_Range_Check_Failed)); | |
2013 | Rewrite (Par, New_Occurrence_Of (Temp, Loc)); | |
2014 | ||
2015 | return; | |
2016 | end; | |
2017 | end if; | |
2018 | ||
7d86aa98 | 2019 | -- Get the (static) bounds of the target type |
5329ca64 | 2020 | |
2021 | Ifirst := Expr_Value (LB); | |
2022 | Ilast := Expr_Value (HB); | |
2023 | ||
7d86aa98 | 2024 | -- A simple optimization: if the expression is a universal literal, |
2025 | -- we can do the comparison with the bounds and the conversion to | |
2026 | -- an integer type statically. The range checks are unchanged. | |
2027 | ||
2028 | if Nkind (Ck_Node) = N_Real_Literal | |
2029 | and then Etype (Ck_Node) = Universal_Real | |
2030 | and then Is_Integer_Type (Target_Typ) | |
2031 | and then Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
2032 | then | |
2033 | declare | |
2034 | Int_Val : constant Uint := UR_To_Uint (Realval (Ck_Node)); | |
2035 | ||
2036 | begin | |
2037 | if Int_Val <= Ilast and then Int_Val >= Ifirst then | |
2038 | ||
4309515d | 2039 | -- Conversion is safe |
7d86aa98 | 2040 | |
2041 | Rewrite (Parent (Ck_Node), | |
2042 | Make_Integer_Literal (Loc, UI_To_Int (Int_Val))); | |
2043 | Analyze_And_Resolve (Parent (Ck_Node), Target_Typ); | |
2044 | return; | |
2045 | end if; | |
2046 | end; | |
2047 | end if; | |
2048 | ||
5329ca64 | 2049 | -- Check against lower bound |
2050 | ||
2af58f67 | 2051 | if Truncate and then Ifirst > 0 then |
2052 | Lo := Pred (Expr_Type, UR_From_Uint (Ifirst)); | |
2053 | Lo_OK := False; | |
2054 | ||
2055 | elsif Truncate then | |
2056 | Lo := Succ (Expr_Type, UR_From_Uint (Ifirst - 1)); | |
2057 | Lo_OK := True; | |
2058 | ||
2059 | elsif abs (Ifirst) < Max_Bound then | |
5329ca64 | 2060 | Lo := UR_From_Uint (Ifirst) - Ureal_Half; |
2061 | Lo_OK := (Ifirst > 0); | |
2af58f67 | 2062 | |
5329ca64 | 2063 | else |
2064 | Lo := Machine (Expr_Type, UR_From_Uint (Ifirst), Round_Even, Ck_Node); | |
2065 | Lo_OK := (Lo >= UR_From_Uint (Ifirst)); | |
2066 | end if; | |
2067 | ||
2068 | if Lo_OK then | |
2069 | ||
2070 | -- Lo_Chk := (X >= Lo) | |
2071 | ||
2072 | Lo_Chk := Make_Op_Ge (Loc, | |
2073 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2074 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
2075 | ||
2076 | else | |
2077 | -- Lo_Chk := (X > Lo) | |
2078 | ||
2079 | Lo_Chk := Make_Op_Gt (Loc, | |
2080 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2081 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
2082 | end if; | |
2083 | ||
2084 | -- Check against higher bound | |
2085 | ||
2af58f67 | 2086 | if Truncate and then Ilast < 0 then |
2087 | Hi := Succ (Expr_Type, UR_From_Uint (Ilast)); | |
b2c42753 | 2088 | Hi_OK := False; |
2af58f67 | 2089 | |
2090 | elsif Truncate then | |
2091 | Hi := Pred (Expr_Type, UR_From_Uint (Ilast + 1)); | |
2092 | Hi_OK := True; | |
2093 | ||
2094 | elsif abs (Ilast) < Max_Bound then | |
5329ca64 | 2095 | Hi := UR_From_Uint (Ilast) + Ureal_Half; |
2096 | Hi_OK := (Ilast < 0); | |
2097 | else | |
2098 | Hi := Machine (Expr_Type, UR_From_Uint (Ilast), Round_Even, Ck_Node); | |
2099 | Hi_OK := (Hi <= UR_From_Uint (Ilast)); | |
2100 | end if; | |
2101 | ||
2102 | if Hi_OK then | |
2103 | ||
2104 | -- Hi_Chk := (X <= Hi) | |
2105 | ||
2106 | Hi_Chk := Make_Op_Le (Loc, | |
2107 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2108 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
2109 | ||
2110 | else | |
2111 | -- Hi_Chk := (X < Hi) | |
2112 | ||
2113 | Hi_Chk := Make_Op_Lt (Loc, | |
2114 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2115 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
2116 | end if; | |
2117 | ||
feff2f05 | 2118 | -- If the bounds of the target type are the same as those of the base |
2119 | -- type, the check is an overflow check as a range check is not | |
2120 | -- performed in these cases. | |
5329ca64 | 2121 | |
2122 | if Expr_Value (Type_Low_Bound (Target_Base)) = Ifirst | |
2123 | and then Expr_Value (Type_High_Bound (Target_Base)) = Ilast | |
2124 | then | |
2125 | Reason := CE_Overflow_Check_Failed; | |
2126 | else | |
2127 | Reason := CE_Range_Check_Failed; | |
2128 | end if; | |
2129 | ||
2130 | -- Raise CE if either conditions does not hold | |
2131 | ||
2132 | Insert_Action (Ck_Node, | |
2133 | Make_Raise_Constraint_Error (Loc, | |
05fcfafb | 2134 | Condition => Make_Op_Not (Loc, Make_And_Then (Loc, Lo_Chk, Hi_Chk)), |
5329ca64 | 2135 | Reason => Reason)); |
2136 | end Apply_Float_Conversion_Check; | |
2137 | ||
ee6ba406 | 2138 | ------------------------ |
2139 | -- Apply_Length_Check -- | |
2140 | ------------------------ | |
2141 | ||
2142 | procedure Apply_Length_Check | |
2143 | (Ck_Node : Node_Id; | |
2144 | Target_Typ : Entity_Id; | |
2145 | Source_Typ : Entity_Id := Empty) | |
2146 | is | |
2147 | begin | |
2148 | Apply_Selected_Length_Checks | |
2149 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
2150 | end Apply_Length_Check; | |
2151 | ||
3b045963 | 2152 | ------------------------------------- |
2153 | -- Apply_Parameter_Aliasing_Checks -- | |
2154 | ------------------------------------- | |
b73adb97 | 2155 | |
3b045963 | 2156 | procedure Apply_Parameter_Aliasing_Checks |
2157 | (Call : Node_Id; | |
2158 | Subp : Entity_Id) | |
2159 | is | |
bb569db0 | 2160 | Loc : constant Source_Ptr := Sloc (Call); |
2161 | ||
3b045963 | 2162 | function May_Cause_Aliasing |
2163 | (Formal_1 : Entity_Id; | |
2164 | Formal_2 : Entity_Id) return Boolean; | |
2165 | -- Determine whether two formal parameters can alias each other | |
2166 | -- depending on their modes. | |
2167 | ||
2168 | function Original_Actual (N : Node_Id) return Node_Id; | |
2169 | -- The expander may replace an actual with a temporary for the sake of | |
2170 | -- side effect removal. The temporary may hide a potential aliasing as | |
2171 | -- it does not share the address of the actual. This routine attempts | |
2172 | -- to retrieve the original actual. | |
2173 | ||
bb569db0 | 2174 | procedure Overlap_Check |
2175 | (Actual_1 : Node_Id; | |
2176 | Actual_2 : Node_Id; | |
2177 | Formal_1 : Entity_Id; | |
2178 | Formal_2 : Entity_Id; | |
2179 | Check : in out Node_Id); | |
2180 | -- Create a check to determine whether Actual_1 overlaps with Actual_2. | |
2181 | -- If detailed exception messages are enabled, the check is augmented to | |
2182 | -- provide information about the names of the corresponding formals. See | |
2183 | -- the body for details. Actual_1 and Actual_2 denote the two actuals to | |
2184 | -- be tested. Formal_1 and Formal_2 denote the corresponding formals. | |
2185 | -- Check contains all and-ed simple tests generated so far or remains | |
2186 | -- unchanged in the case of detailed exception messaged. | |
2187 | ||
3b045963 | 2188 | ------------------------ |
2189 | -- May_Cause_Aliasing -- | |
2190 | ------------------------ | |
b73adb97 | 2191 | |
3b045963 | 2192 | function May_Cause_Aliasing |
4a9e7f0c | 2193 | (Formal_1 : Entity_Id; |
3b045963 | 2194 | Formal_2 : Entity_Id) return Boolean |
2195 | is | |
2196 | begin | |
2197 | -- The following combination cannot lead to aliasing | |
2198 | ||
2199 | -- Formal 1 Formal 2 | |
2200 | -- IN IN | |
2201 | ||
2202 | if Ekind (Formal_1) = E_In_Parameter | |
a45d946f | 2203 | and then |
2204 | Ekind (Formal_2) = E_In_Parameter | |
3b045963 | 2205 | then |
2206 | return False; | |
2207 | ||
2208 | -- The following combinations may lead to aliasing | |
2209 | ||
2210 | -- Formal 1 Formal 2 | |
2211 | -- IN OUT | |
2212 | -- IN IN OUT | |
2213 | -- OUT IN | |
2214 | -- OUT IN OUT | |
2215 | -- OUT OUT | |
2216 | ||
2217 | else | |
2218 | return True; | |
2219 | end if; | |
2220 | end May_Cause_Aliasing; | |
2221 | ||
2222 | --------------------- | |
2223 | -- Original_Actual -- | |
2224 | --------------------- | |
2225 | ||
2226 | function Original_Actual (N : Node_Id) return Node_Id is | |
2227 | begin | |
2228 | if Nkind (N) = N_Type_Conversion then | |
2229 | return Expression (N); | |
2230 | ||
2231 | -- The expander created a temporary to capture the result of a type | |
2232 | -- conversion where the expression is the real actual. | |
2233 | ||
2234 | elsif Nkind (N) = N_Identifier | |
2235 | and then Present (Original_Node (N)) | |
2236 | and then Nkind (Original_Node (N)) = N_Type_Conversion | |
2237 | then | |
2238 | return Expression (Original_Node (N)); | |
2239 | end if; | |
2240 | ||
2241 | return N; | |
2242 | end Original_Actual; | |
2243 | ||
bb569db0 | 2244 | ------------------- |
2245 | -- Overlap_Check -- | |
2246 | ------------------- | |
2247 | ||
2248 | procedure Overlap_Check | |
2249 | (Actual_1 : Node_Id; | |
2250 | Actual_2 : Node_Id; | |
2251 | Formal_1 : Entity_Id; | |
2252 | Formal_2 : Entity_Id; | |
2253 | Check : in out Node_Id) | |
2254 | is | |
29448168 | 2255 | Cond : Node_Id; |
2256 | ID_Casing : constant Casing_Type := | |
2257 | Identifier_Casing (Source_Index (Current_Sem_Unit)); | |
bb569db0 | 2258 | |
2259 | begin | |
2260 | -- Generate: | |
2261 | -- Actual_1'Overlaps_Storage (Actual_2) | |
2262 | ||
2263 | Cond := | |
2264 | Make_Attribute_Reference (Loc, | |
2265 | Prefix => New_Copy_Tree (Original_Actual (Actual_1)), | |
2266 | Attribute_Name => Name_Overlaps_Storage, | |
2267 | Expressions => | |
2268 | New_List (New_Copy_Tree (Original_Actual (Actual_2)))); | |
2269 | ||
2270 | -- Generate the following check when detailed exception messages are | |
2271 | -- enabled: | |
2272 | ||
2273 | -- if Actual_1'Overlaps_Storage (Actual_2) then | |
2274 | -- raise Program_Error with <detailed message>; | |
2275 | -- end if; | |
2276 | ||
2277 | if Exception_Extra_Info then | |
2278 | Start_String; | |
2279 | ||
2280 | -- Do not generate location information for internal calls | |
2281 | ||
2282 | if Comes_From_Source (Call) then | |
2283 | Store_String_Chars (Build_Location_String (Loc)); | |
2284 | Store_String_Char (' '); | |
2285 | end if; | |
2286 | ||
2287 | Store_String_Chars ("aliased parameters, actuals for """); | |
29448168 | 2288 | |
2289 | Get_Name_String (Chars (Formal_1)); | |
2290 | Set_Casing (ID_Casing); | |
2291 | Store_String_Chars (Name_Buffer (1 .. Name_Len)); | |
2292 | ||
bb569db0 | 2293 | Store_String_Chars (""" and """); |
29448168 | 2294 | |
2295 | Get_Name_String (Chars (Formal_2)); | |
2296 | Set_Casing (ID_Casing); | |
2297 | Store_String_Chars (Name_Buffer (1 .. Name_Len)); | |
2298 | ||
bb569db0 | 2299 | Store_String_Chars (""" overlap"); |
2300 | ||
2301 | Insert_Action (Call, | |
2302 | Make_If_Statement (Loc, | |
2303 | Condition => Cond, | |
2304 | Then_Statements => New_List ( | |
2305 | Make_Raise_Statement (Loc, | |
2306 | Name => | |
83c6c069 | 2307 | New_Occurrence_Of (Standard_Program_Error, Loc), |
bb569db0 | 2308 | Expression => Make_String_Literal (Loc, End_String))))); |
2309 | ||
2310 | -- Create a sequence of overlapping checks by and-ing them all | |
2311 | -- together. | |
2312 | ||
2313 | else | |
2314 | if No (Check) then | |
2315 | Check := Cond; | |
2316 | else | |
2317 | Check := | |
2318 | Make_And_Then (Loc, | |
2319 | Left_Opnd => Check, | |
2320 | Right_Opnd => Cond); | |
2321 | end if; | |
2322 | end if; | |
2323 | end Overlap_Check; | |
2324 | ||
3b045963 | 2325 | -- Local variables |
2326 | ||
15fca308 | 2327 | Actual_1 : Node_Id; |
2328 | Actual_2 : Node_Id; | |
2329 | Check : Node_Id; | |
2330 | Formal_1 : Entity_Id; | |
2331 | Formal_2 : Entity_Id; | |
2332 | Orig_Act_1 : Node_Id; | |
2333 | Orig_Act_2 : Node_Id; | |
3b045963 | 2334 | |
2335 | -- Start of processing for Apply_Parameter_Aliasing_Checks | |
2336 | ||
2337 | begin | |
bb569db0 | 2338 | Check := Empty; |
3b045963 | 2339 | |
2340 | Actual_1 := First_Actual (Call); | |
2341 | Formal_1 := First_Formal (Subp); | |
2342 | while Present (Actual_1) and then Present (Formal_1) loop | |
15fca308 | 2343 | Orig_Act_1 := Original_Actual (Actual_1); |
3b045963 | 2344 | |
2345 | -- Ensure that the actual is an object that is not passed by value. | |
2346 | -- Elementary types are always passed by value, therefore actuals of | |
747426db | 2347 | -- such types cannot lead to aliasing. An aggregate is an object in |
2348 | -- Ada 2012, but an actual that is an aggregate cannot overlap with | |
4dc3174c | 2349 | -- another actual. A type that is By_Reference (such as an array of |
2350 | -- controlled types) is not subject to the check because any update | |
2351 | -- will be done in place and a subsequent read will always see the | |
2352 | -- correct value, see RM 6.2 (12/3). | |
3b045963 | 2353 | |
15fca308 | 2354 | if Nkind (Orig_Act_1) = N_Aggregate |
2355 | or else (Nkind (Orig_Act_1) = N_Qualified_Expression | |
2356 | and then Nkind (Expression (Orig_Act_1)) = N_Aggregate) | |
747426db | 2357 | then |
2358 | null; | |
2359 | ||
15fca308 | 2360 | elsif Is_Object_Reference (Orig_Act_1) |
2361 | and then not Is_Elementary_Type (Etype (Orig_Act_1)) | |
2362 | and then not Is_By_Reference_Type (Etype (Orig_Act_1)) | |
3b045963 | 2363 | then |
2364 | Actual_2 := Next_Actual (Actual_1); | |
2365 | Formal_2 := Next_Formal (Formal_1); | |
2366 | while Present (Actual_2) and then Present (Formal_2) loop | |
15fca308 | 2367 | Orig_Act_2 := Original_Actual (Actual_2); |
3b045963 | 2368 | |
2369 | -- The other actual we are testing against must also denote | |
2370 | -- a non pass-by-value object. Generate the check only when | |
2371 | -- the mode of the two formals may lead to aliasing. | |
2372 | ||
15fca308 | 2373 | if Is_Object_Reference (Orig_Act_2) |
2374 | and then not Is_Elementary_Type (Etype (Orig_Act_2)) | |
3b045963 | 2375 | and then May_Cause_Aliasing (Formal_1, Formal_2) |
2376 | then | |
72f889fa | 2377 | Remove_Side_Effects (Actual_1); |
2378 | Remove_Side_Effects (Actual_2); | |
2379 | ||
bb569db0 | 2380 | Overlap_Check |
2381 | (Actual_1 => Actual_1, | |
2382 | Actual_2 => Actual_2, | |
2383 | Formal_1 => Formal_1, | |
2384 | Formal_2 => Formal_2, | |
2385 | Check => Check); | |
3b045963 | 2386 | end if; |
2387 | ||
2388 | Next_Actual (Actual_2); | |
2389 | Next_Formal (Formal_2); | |
2390 | end loop; | |
2391 | end if; | |
2392 | ||
2393 | Next_Actual (Actual_1); | |
2394 | Next_Formal (Formal_1); | |
2395 | end loop; | |
2396 | ||
bb569db0 | 2397 | -- Place a simple check right before the call |
3b045963 | 2398 | |
bb569db0 | 2399 | if Present (Check) and then not Exception_Extra_Info then |
3b045963 | 2400 | Insert_Action (Call, |
2401 | Make_Raise_Program_Error (Loc, | |
bb569db0 | 2402 | Condition => Check, |
2403 | Reason => PE_Aliased_Parameters)); | |
3b045963 | 2404 | end if; |
2405 | end Apply_Parameter_Aliasing_Checks; | |
2406 | ||
2407 | ------------------------------------- | |
2408 | -- Apply_Parameter_Validity_Checks -- | |
2409 | ------------------------------------- | |
2410 | ||
2411 | procedure Apply_Parameter_Validity_Checks (Subp : Entity_Id) is | |
2412 | Subp_Decl : Node_Id; | |
b73adb97 | 2413 | |
4a9e7f0c | 2414 | procedure Add_Validity_Check |
ed695684 | 2415 | (Formal : Entity_Id; |
2416 | Prag_Nam : Name_Id; | |
4a9e7f0c | 2417 | For_Result : Boolean := False); |
2418 | -- Add a single 'Valid[_Scalar] check which verifies the initialization | |
ed695684 | 2419 | -- of Formal. Prag_Nam denotes the pre or post condition pragma name. |
4a9e7f0c | 2420 | -- Set flag For_Result when to verify the result of a function. |
b73adb97 | 2421 | |
b73adb97 | 2422 | ------------------------ |
2423 | -- Add_Validity_Check -- | |
2424 | ------------------------ | |
2425 | ||
2426 | procedure Add_Validity_Check | |
ed695684 | 2427 | (Formal : Entity_Id; |
2428 | Prag_Nam : Name_Id; | |
b73adb97 | 2429 | For_Result : Boolean := False) |
2430 | is | |
ed695684 | 2431 | procedure Build_Pre_Post_Condition (Expr : Node_Id); |
2432 | -- Create a pre/postcondition pragma that tests expression Expr | |
2433 | ||
2434 | ------------------------------ | |
2435 | -- Build_Pre_Post_Condition -- | |
2436 | ------------------------------ | |
2437 | ||
2438 | procedure Build_Pre_Post_Condition (Expr : Node_Id) is | |
2439 | Loc : constant Source_Ptr := Sloc (Subp); | |
2440 | Decls : List_Id; | |
2441 | Prag : Node_Id; | |
2442 | ||
2443 | begin | |
2444 | Prag := | |
2445 | Make_Pragma (Loc, | |
c33cb5ff | 2446 | Chars => Prag_Nam, |
ed695684 | 2447 | Pragma_Argument_Associations => New_List ( |
2448 | Make_Pragma_Argument_Association (Loc, | |
2449 | Chars => Name_Check, | |
2450 | Expression => Expr))); | |
2451 | ||
2452 | -- Add a message unless exception messages are suppressed | |
2453 | ||
2454 | if not Exception_Locations_Suppressed then | |
2455 | Append_To (Pragma_Argument_Associations (Prag), | |
2456 | Make_Pragma_Argument_Association (Loc, | |
2457 | Chars => Name_Message, | |
2458 | Expression => | |
2459 | Make_String_Literal (Loc, | |
2460 | Strval => "failed " | |
2461 | & Get_Name_String (Prag_Nam) | |
2462 | & " from " | |
2463 | & Build_Location_String (Loc)))); | |
2464 | end if; | |
2465 | ||
2466 | -- Insert the pragma in the tree | |
2467 | ||
2468 | if Nkind (Parent (Subp_Decl)) = N_Compilation_Unit then | |
2469 | Add_Global_Declaration (Prag); | |
2470 | Analyze (Prag); | |
2471 | ||
2472 | -- PPC pragmas associated with subprogram bodies must be inserted | |
2473 | -- in the declarative part of the body. | |
2474 | ||
2475 | elsif Nkind (Subp_Decl) = N_Subprogram_Body then | |
2476 | Decls := Declarations (Subp_Decl); | |
2477 | ||
2478 | if No (Decls) then | |
2479 | Decls := New_List; | |
2480 | Set_Declarations (Subp_Decl, Decls); | |
2481 | end if; | |
2482 | ||
2483 | Prepend_To (Decls, Prag); | |
2484 | Analyze (Prag); | |
2485 | ||
2486 | -- For subprogram declarations insert the PPC pragma right after | |
2487 | -- the declarative node. | |
2488 | ||
2489 | else | |
2490 | Insert_After_And_Analyze (Subp_Decl, Prag); | |
2491 | end if; | |
2492 | end Build_Pre_Post_Condition; | |
2493 | ||
2494 | -- Local variables | |
2495 | ||
4a9e7f0c | 2496 | Loc : constant Source_Ptr := Sloc (Subp); |
ed695684 | 2497 | Typ : constant Entity_Id := Etype (Formal); |
b73adb97 | 2498 | Check : Node_Id; |
2499 | Nam : Name_Id; | |
2500 | ||
ed695684 | 2501 | -- Start of processing for Add_Validity_Check |
2502 | ||
b73adb97 | 2503 | begin |
9916a361 | 2504 | -- For scalars, generate 'Valid test |
b73adb97 | 2505 | |
2506 | if Is_Scalar_Type (Typ) then | |
2507 | Nam := Name_Valid; | |
9916a361 | 2508 | |
2509 | -- For any non-scalar with scalar parts, generate 'Valid_Scalars test | |
2510 | ||
2511 | elsif Scalar_Part_Present (Typ) then | |
b73adb97 | 2512 | Nam := Name_Valid_Scalars; |
9916a361 | 2513 | |
2514 | -- No test needed for other cases (no scalars to test) | |
2515 | ||
b73adb97 | 2516 | else |
2517 | return; | |
2518 | end if; | |
2519 | ||
2520 | -- Step 1: Create the expression to verify the validity of the | |
2521 | -- context. | |
2522 | ||
ed695684 | 2523 | Check := New_Occurrence_Of (Formal, Loc); |
b73adb97 | 2524 | |
2525 | -- When processing a function result, use 'Result. Generate | |
2526 | -- Context'Result | |
2527 | ||
2528 | if For_Result then | |
2529 | Check := | |
2530 | Make_Attribute_Reference (Loc, | |
2531 | Prefix => Check, | |
2532 | Attribute_Name => Name_Result); | |
2533 | end if; | |
2534 | ||
2535 | -- Generate: | |
2536 | -- Context['Result]'Valid[_Scalars] | |
2537 | ||
2538 | Check := | |
2539 | Make_Attribute_Reference (Loc, | |
2540 | Prefix => Check, | |
2541 | Attribute_Name => Nam); | |
2542 | ||
4a9e7f0c | 2543 | -- Step 2: Create a pre or post condition pragma |
2544 | ||
ed695684 | 2545 | Build_Pre_Post_Condition (Check); |
4a9e7f0c | 2546 | end Add_Validity_Check; |
2547 | ||
4a9e7f0c | 2548 | -- Local variables |
2549 | ||
2550 | Formal : Entity_Id; | |
4a9e7f0c | 2551 | Subp_Spec : Node_Id; |
2552 | ||
3b045963 | 2553 | -- Start of processing for Apply_Parameter_Validity_Checks |
b73adb97 | 2554 | |
2555 | begin | |
4a9e7f0c | 2556 | -- Extract the subprogram specification and declaration nodes |
b73adb97 | 2557 | |
4a9e7f0c | 2558 | Subp_Spec := Parent (Subp); |
a45d946f | 2559 | |
4a9e7f0c | 2560 | if Nkind (Subp_Spec) = N_Defining_Program_Unit_Name then |
2561 | Subp_Spec := Parent (Subp_Spec); | |
2562 | end if; | |
a45d946f | 2563 | |
4a9e7f0c | 2564 | Subp_Decl := Parent (Subp_Spec); |
9e58d7ed | 2565 | |
b73adb97 | 2566 | if not Comes_From_Source (Subp) |
4a9e7f0c | 2567 | |
2568 | -- Do not process formal subprograms because the corresponding actual | |
2569 | -- will receive the proper checks when the instance is analyzed. | |
2570 | ||
2571 | or else Is_Formal_Subprogram (Subp) | |
2572 | ||
95ac2d90 | 2573 | -- Do not process imported subprograms since pre and postconditions |
a45d946f | 2574 | -- are never verified on routines coming from a different language. |
4a9e7f0c | 2575 | |
b73adb97 | 2576 | or else Is_Imported (Subp) |
2577 | or else Is_Intrinsic_Subprogram (Subp) | |
4a9e7f0c | 2578 | |
a45d946f | 2579 | -- The PPC pragmas generated by this routine do not correspond to |
2580 | -- source aspects, therefore they cannot be applied to abstract | |
2581 | -- subprograms. | |
4a9e7f0c | 2582 | |
7c443ae8 | 2583 | or else Nkind (Subp_Decl) = N_Abstract_Subprogram_Declaration |
4a9e7f0c | 2584 | |
a45d946f | 2585 | -- Do not consider subprogram renaminds because the renamed entity |
2586 | -- already has the proper PPC pragmas. | |
1bd93de5 | 2587 | |
2588 | or else Nkind (Subp_Decl) = N_Subprogram_Renaming_Declaration | |
2589 | ||
a45d946f | 2590 | -- Do not process null procedures because there is no benefit of |
2591 | -- adding the checks to a no action routine. | |
4a9e7f0c | 2592 | |
2593 | or else (Nkind (Subp_Spec) = N_Procedure_Specification | |
a45d946f | 2594 | and then Null_Present (Subp_Spec)) |
b73adb97 | 2595 | then |
2596 | return; | |
2597 | end if; | |
2598 | ||
4a9e7f0c | 2599 | -- Inspect all the formals applying aliasing and scalar initialization |
2600 | -- checks where applicable. | |
b73adb97 | 2601 | |
2602 | Formal := First_Formal (Subp); | |
2603 | while Present (Formal) loop | |
4a9e7f0c | 2604 | |
2605 | -- Generate the following scalar initialization checks for each | |
2606 | -- formal parameter: | |
2607 | ||
2608 | -- mode IN - Pre => Formal'Valid[_Scalars] | |
2609 | -- mode IN OUT - Pre, Post => Formal'Valid[_Scalars] | |
2610 | -- mode OUT - Post => Formal'Valid[_Scalars] | |
2611 | ||
2612 | if Check_Validity_Of_Parameters then | |
2613 | if Ekind_In (Formal, E_In_Parameter, E_In_Out_Parameter) then | |
2614 | Add_Validity_Check (Formal, Name_Precondition, False); | |
2615 | end if; | |
2616 | ||
2617 | if Ekind_In (Formal, E_In_Out_Parameter, E_Out_Parameter) then | |
2618 | Add_Validity_Check (Formal, Name_Postcondition, False); | |
2619 | end if; | |
b73adb97 | 2620 | end if; |
2621 | ||
b73adb97 | 2622 | Next_Formal (Formal); |
2623 | end loop; | |
2624 | ||
a45d946f | 2625 | -- Generate following scalar initialization check for function result: |
4a9e7f0c | 2626 | |
2627 | -- Post => Subp'Result'Valid[_Scalars] | |
b73adb97 | 2628 | |
a45d946f | 2629 | if Check_Validity_Of_Parameters and then Ekind (Subp) = E_Function then |
4a9e7f0c | 2630 | Add_Validity_Check (Subp, Name_Postcondition, True); |
b73adb97 | 2631 | end if; |
3b045963 | 2632 | end Apply_Parameter_Validity_Checks; |
b73adb97 | 2633 | |
7aafae1c | 2634 | --------------------------- |
2635 | -- Apply_Predicate_Check -- | |
2636 | --------------------------- | |
2637 | ||
e60047e5 | 2638 | procedure Apply_Predicate_Check |
2639 | (N : Node_Id; | |
2640 | Typ : Entity_Id; | |
2641 | Fun : Entity_Id := Empty) | |
2642 | is | |
301d5ec3 | 2643 | S : Entity_Id; |
9e58d7ed | 2644 | |
7aafae1c | 2645 | begin |
da2270e7 | 2646 | if Predicate_Checks_Suppressed (Empty) then |
2647 | return; | |
301d5ec3 | 2648 | |
2c011bc5 | 2649 | elsif Predicates_Ignored (Typ) then |
2650 | return; | |
2651 | ||
da2270e7 | 2652 | elsif Present (Predicate_Function (Typ)) then |
301d5ec3 | 2653 | S := Current_Scope; |
9e58d7ed | 2654 | while Present (S) and then not Is_Subprogram (S) loop |
301d5ec3 | 2655 | S := Scope (S); |
2656 | end loop; | |
2657 | ||
ea822fd4 | 2658 | -- A predicate check does not apply within internally generated |
2659 | -- subprograms, such as TSS functions. | |
2660 | ||
2661 | if Within_Internal_Subprogram then | |
301d5ec3 | 2662 | return; |
22631b41 | 2663 | |
96a2d100 | 2664 | -- If the check appears within the predicate function itself, it |
2665 | -- means that the user specified a check whose formal is the | |
2666 | -- predicated subtype itself, rather than some covering type. This | |
2667 | -- is likely to be a common error, and thus deserves a warning. | |
22631b41 | 2668 | |
0e9014a7 | 2669 | elsif Present (S) and then S = Predicate_Function (Typ) then |
e60047e5 | 2670 | Error_Msg_NE |
0c4abd51 | 2671 | ("predicate check includes a call to& that requires a " |
2672 | & "predicate check??", Parent (N), Fun); | |
96a2d100 | 2673 | Error_Msg_N |
cb97ae5c | 2674 | ("\this will result in infinite recursion??", Parent (N)); |
e60047e5 | 2675 | |
2676 | if Is_First_Subtype (Typ) then | |
2677 | Error_Msg_NE | |
0c4abd51 | 2678 | ("\use an explicit subtype of& to carry the predicate", |
e60047e5 | 2679 | Parent (N), Typ); |
2680 | end if; | |
2681 | ||
96a2d100 | 2682 | Insert_Action (N, |
61016a7a | 2683 | Make_Raise_Storage_Error (Sloc (N), |
2684 | Reason => SE_Infinite_Recursion)); | |
22631b41 | 2685 | |
64cc9e5d | 2686 | -- Here for normal case of predicate active |
e6281d47 | 2687 | |
61016a7a | 2688 | else |
b04165c4 | 2689 | -- If the type has a static predicate and the expression is known |
2690 | -- at compile time, see if the expression satisfies the predicate. | |
3a75f20b | 2691 | |
2692 | Check_Expression_Against_Static_Predicate (N, Typ); | |
e6281d47 | 2693 | |
e34cd69d | 2694 | if not Expander_Active then |
2695 | return; | |
2696 | end if; | |
2697 | ||
2698 | -- For an entity of the type, generate a call to the predicate | |
2699 | -- function, unless its type is an actual subtype, which is not | |
2700 | -- visible outside of the enclosing subprogram. | |
2701 | ||
2702 | if Is_Entity_Name (N) | |
2703 | and then not Is_Actual_Subtype (Typ) | |
2704 | then | |
da2270e7 | 2705 | Insert_Action (N, |
2706 | Make_Predicate_Check | |
2707 | (Typ, New_Occurrence_Of (Entity (N), Sloc (N)))); | |
2708 | ||
f9906591 | 2709 | -- If the expression is not an entity it may have side effects, |
bc885df9 | 2710 | -- and the following call will create an object declaration for |
2711 | -- it. We disable checks during its analysis, to prevent an | |
2712 | -- infinite recursion. | |
da2270e7 | 2713 | |
e3b910d8 | 2714 | -- If the prefix is an aggregate in an assignment, apply the |
2715 | -- check to the LHS after assignment, rather than create a | |
2716 | -- redundant temporary. This is only necessary in rare cases | |
2717 | -- of array types (including strings) initialized with an | |
2718 | -- aggregate with an "others" clause, either coming from source | |
2719 | -- or generated by an Initialize_Scalars pragma. | |
2720 | ||
2721 | elsif Nkind (N) = N_Aggregate | |
2722 | and then Nkind (Parent (N)) = N_Assignment_Statement | |
2723 | then | |
2724 | Insert_Action_After (Parent (N), | |
2725 | Make_Predicate_Check | |
2726 | (Typ, Duplicate_Subexpr (Name (Parent (N))))); | |
2727 | ||
da2270e7 | 2728 | else |
2729 | Insert_Action (N, | |
bc885df9 | 2730 | Make_Predicate_Check |
2731 | (Typ, Duplicate_Subexpr (N)), Suppress => All_Checks); | |
da2270e7 | 2732 | end if; |
301d5ec3 | 2733 | end if; |
7aafae1c | 2734 | end if; |
2735 | end Apply_Predicate_Check; | |
2736 | ||
ee6ba406 | 2737 | ----------------------- |
2738 | -- Apply_Range_Check -- | |
2739 | ----------------------- | |
2740 | ||
2741 | procedure Apply_Range_Check | |
2742 | (Ck_Node : Node_Id; | |
2743 | Target_Typ : Entity_Id; | |
2744 | Source_Typ : Entity_Id := Empty) | |
2745 | is | |
2746 | begin | |
2747 | Apply_Selected_Range_Checks | |
2748 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
2749 | end Apply_Range_Check; | |
2750 | ||
2751 | ------------------------------ | |
2752 | -- Apply_Scalar_Range_Check -- | |
2753 | ------------------------------ | |
2754 | ||
feff2f05 | 2755 | -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag |
2756 | -- off if it is already set on. | |
ee6ba406 | 2757 | |
2758 | procedure Apply_Scalar_Range_Check | |
2759 | (Expr : Node_Id; | |
2760 | Target_Typ : Entity_Id; | |
2761 | Source_Typ : Entity_Id := Empty; | |
2762 | Fixed_Int : Boolean := False) | |
2763 | is | |
2764 | Parnt : constant Node_Id := Parent (Expr); | |
2765 | S_Typ : Entity_Id; | |
2766 | Arr : Node_Id := Empty; -- initialize to prevent warning | |
2767 | Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning | |
16149377 | 2768 | OK : Boolean := False; -- initialize to prevent warning |
ee6ba406 | 2769 | |
2770 | Is_Subscr_Ref : Boolean; | |
2771 | -- Set true if Expr is a subscript | |
2772 | ||
2773 | Is_Unconstrained_Subscr_Ref : Boolean; | |
2774 | -- Set true if Expr is a subscript of an unconstrained array. In this | |
2775 | -- case we do not attempt to do an analysis of the value against the | |
2776 | -- range of the subscript, since we don't know the actual subtype. | |
2777 | ||
2778 | Int_Real : Boolean; | |
feff2f05 | 2779 | -- Set to True if Expr should be regarded as a real value even though |
2780 | -- the type of Expr might be discrete. | |
ee6ba406 | 2781 | |
a0a15971 | 2782 | procedure Bad_Value (Warn : Boolean := False); |
2783 | -- Procedure called if value is determined to be out of range. Warn is | |
2784 | -- True to force a warning instead of an error, even when SPARK_Mode is | |
2785 | -- On. | |
ee6ba406 | 2786 | |
9dfe12ae | 2787 | --------------- |
2788 | -- Bad_Value -- | |
2789 | --------------- | |
2790 | ||
a0a15971 | 2791 | procedure Bad_Value (Warn : Boolean := False) is |
ee6ba406 | 2792 | begin |
2793 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 2794 | (Expr, "value not in range of}??", CE_Range_Check_Failed, |
a0a15971 | 2795 | Ent => Target_Typ, |
2796 | Typ => Target_Typ, | |
2797 | Warn => Warn); | |
ee6ba406 | 2798 | end Bad_Value; |
2799 | ||
9dfe12ae | 2800 | -- Start of processing for Apply_Scalar_Range_Check |
2801 | ||
ee6ba406 | 2802 | begin |
2af58f67 | 2803 | -- Return if check obviously not needed |
ee6ba406 | 2804 | |
2af58f67 | 2805 | if |
2806 | -- Not needed inside generic | |
ee6ba406 | 2807 | |
2af58f67 | 2808 | Inside_A_Generic |
2809 | ||
2810 | -- Not needed if previous error | |
2811 | ||
2812 | or else Target_Typ = Any_Type | |
2813 | or else Nkind (Expr) = N_Error | |
2814 | ||
2815 | -- Not needed for non-scalar type | |
2816 | ||
2817 | or else not Is_Scalar_Type (Target_Typ) | |
2818 | ||
2819 | -- Not needed if we know node raises CE already | |
2820 | ||
2821 | or else Raises_Constraint_Error (Expr) | |
ee6ba406 | 2822 | then |
2823 | return; | |
2824 | end if; | |
2825 | ||
2826 | -- Now, see if checks are suppressed | |
2827 | ||
2828 | Is_Subscr_Ref := | |
2829 | Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component; | |
2830 | ||
2831 | if Is_Subscr_Ref then | |
2832 | Arr := Prefix (Parnt); | |
2833 | Arr_Typ := Get_Actual_Subtype_If_Available (Arr); | |
cce84b09 | 2834 | |
a3a76ccc | 2835 | if Is_Access_Type (Arr_Typ) then |
245e87df | 2836 | Arr_Typ := Designated_Type (Arr_Typ); |
a3a76ccc | 2837 | end if; |
ee6ba406 | 2838 | end if; |
2839 | ||
2840 | if not Do_Range_Check (Expr) then | |
2841 | ||
2842 | -- Subscript reference. Check for Index_Checks suppressed | |
2843 | ||
2844 | if Is_Subscr_Ref then | |
2845 | ||
2846 | -- Check array type and its base type | |
2847 | ||
2848 | if Index_Checks_Suppressed (Arr_Typ) | |
9dfe12ae | 2849 | or else Index_Checks_Suppressed (Base_Type (Arr_Typ)) |
ee6ba406 | 2850 | then |
2851 | return; | |
2852 | ||
2853 | -- Check array itself if it is an entity name | |
2854 | ||
2855 | elsif Is_Entity_Name (Arr) | |
9dfe12ae | 2856 | and then Index_Checks_Suppressed (Entity (Arr)) |
ee6ba406 | 2857 | then |
2858 | return; | |
2859 | ||
2860 | -- Check expression itself if it is an entity name | |
2861 | ||
2862 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 2863 | and then Index_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 2864 | then |
2865 | return; | |
2866 | end if; | |
2867 | ||
2868 | -- All other cases, check for Range_Checks suppressed | |
2869 | ||
2870 | else | |
2871 | -- Check target type and its base type | |
2872 | ||
2873 | if Range_Checks_Suppressed (Target_Typ) | |
9dfe12ae | 2874 | or else Range_Checks_Suppressed (Base_Type (Target_Typ)) |
ee6ba406 | 2875 | then |
2876 | return; | |
2877 | ||
2878 | -- Check expression itself if it is an entity name | |
2879 | ||
2880 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 2881 | and then Range_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 2882 | then |
2883 | return; | |
2884 | ||
feff2f05 | 2885 | -- If Expr is part of an assignment statement, then check left |
2886 | -- side of assignment if it is an entity name. | |
ee6ba406 | 2887 | |
2888 | elsif Nkind (Parnt) = N_Assignment_Statement | |
2889 | and then Is_Entity_Name (Name (Parnt)) | |
9dfe12ae | 2890 | and then Range_Checks_Suppressed (Entity (Name (Parnt))) |
ee6ba406 | 2891 | then |
2892 | return; | |
2893 | end if; | |
2894 | end if; | |
2895 | end if; | |
2896 | ||
9dfe12ae | 2897 | -- Do not set range checks if they are killed |
2898 | ||
2899 | if Nkind (Expr) = N_Unchecked_Type_Conversion | |
2900 | and then Kill_Range_Check (Expr) | |
2901 | then | |
2902 | return; | |
2903 | end if; | |
2904 | ||
2905 | -- Do not set range checks for any values from System.Scalar_Values | |
39a0c1d3 | 2906 | -- since the whole idea of such values is to avoid checking them. |
9dfe12ae | 2907 | |
2908 | if Is_Entity_Name (Expr) | |
2909 | and then Is_RTU (Scope (Entity (Expr)), System_Scalar_Values) | |
2910 | then | |
2911 | return; | |
2912 | end if; | |
2913 | ||
ee6ba406 | 2914 | -- Now see if we need a check |
2915 | ||
2916 | if No (Source_Typ) then | |
2917 | S_Typ := Etype (Expr); | |
2918 | else | |
2919 | S_Typ := Source_Typ; | |
2920 | end if; | |
2921 | ||
2922 | if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then | |
2923 | return; | |
2924 | end if; | |
2925 | ||
2926 | Is_Unconstrained_Subscr_Ref := | |
2927 | Is_Subscr_Ref and then not Is_Constrained (Arr_Typ); | |
2928 | ||
b40670e1 | 2929 | -- Special checks for floating-point type |
ee6ba406 | 2930 | |
b40670e1 | 2931 | if Is_Floating_Point_Type (S_Typ) then |
2932 | ||
2933 | -- Always do a range check if the source type includes infinities and | |
2934 | -- the target type does not include infinities. We do not do this if | |
2935 | -- range checks are killed. | |
cb388b10 | 2936 | -- If the expression is a literal and the bounds of the type are |
2937 | -- static constants it may be possible to optimize the check. | |
b40670e1 | 2938 | |
2939 | if Has_Infinities (S_Typ) | |
2940 | and then not Has_Infinities (Target_Typ) | |
2941 | then | |
cb388b10 | 2942 | -- If the expression is a literal and the bounds of the type are |
2943 | -- static constants it may be possible to optimize the check. | |
2944 | ||
2945 | if Nkind (Expr) = N_Real_Literal then | |
2946 | declare | |
2947 | Tlo : constant Node_Id := Type_Low_Bound (Target_Typ); | |
2948 | Thi : constant Node_Id := Type_High_Bound (Target_Typ); | |
2949 | ||
2950 | begin | |
2951 | if Compile_Time_Known_Value (Tlo) | |
2952 | and then Compile_Time_Known_Value (Thi) | |
2953 | and then Expr_Value_R (Expr) >= Expr_Value_R (Tlo) | |
2954 | and then Expr_Value_R (Expr) <= Expr_Value_R (Thi) | |
2955 | then | |
2956 | return; | |
2957 | else | |
2958 | Enable_Range_Check (Expr); | |
2959 | end if; | |
2960 | end; | |
2961 | ||
2962 | else | |
2963 | Enable_Range_Check (Expr); | |
2964 | end if; | |
b40670e1 | 2965 | end if; |
ee6ba406 | 2966 | end if; |
2967 | ||
feff2f05 | 2968 | -- Return if we know expression is definitely in the range of the target |
2969 | -- type as determined by Determine_Range. Right now we only do this for | |
2970 | -- discrete types, and not fixed-point or floating-point types. | |
ee6ba406 | 2971 | |
f2a06be9 | 2972 | -- The additional less-precise tests below catch these cases |
ee6ba406 | 2973 | |
54022749 | 2974 | -- In GNATprove_Mode, also deal with the case of a conversion from |
2975 | -- floating-point to integer. It is only possible because analysis | |
2976 | -- in GNATprove rules out the possibility of a NaN or infinite value. | |
2977 | ||
feff2f05 | 2978 | -- Note: skip this if we are given a source_typ, since the point of |
2979 | -- supplying a Source_Typ is to stop us looking at the expression. | |
2980 | -- We could sharpen this test to be out parameters only ??? | |
ee6ba406 | 2981 | |
2982 | if Is_Discrete_Type (Target_Typ) | |
54022749 | 2983 | and then (Is_Discrete_Type (Etype (Expr)) |
2984 | or else (GNATprove_Mode | |
2985 | and then Is_Floating_Point_Type (Etype (Expr)))) | |
ee6ba406 | 2986 | and then not Is_Unconstrained_Subscr_Ref |
2987 | and then No (Source_Typ) | |
2988 | then | |
2989 | declare | |
ee6ba406 | 2990 | Thi : constant Node_Id := Type_High_Bound (Target_Typ); |
552d7cbc | 2991 | Tlo : constant Node_Id := Type_Low_Bound (Target_Typ); |
ee6ba406 | 2992 | |
2993 | begin | |
2994 | if Compile_Time_Known_Value (Tlo) | |
2995 | and then Compile_Time_Known_Value (Thi) | |
2996 | then | |
9dfe12ae | 2997 | declare |
9dfe12ae | 2998 | Hiv : constant Uint := Expr_Value (Thi); |
552d7cbc | 2999 | Lov : constant Uint := Expr_Value (Tlo); |
54022749 | 3000 | Hi : Uint; |
552d7cbc | 3001 | Lo : Uint; |
ee6ba406 | 3002 | |
9dfe12ae | 3003 | begin |
552d7cbc | 3004 | -- If range is null, we for sure have a constraint error (we |
3005 | -- don't even need to look at the value involved, since all | |
3006 | -- possible values will raise CE). | |
9dfe12ae | 3007 | |
3008 | if Lov > Hiv then | |
f4f2bf51 | 3009 | |
a0a15971 | 3010 | -- When SPARK_Mode is On, force a warning instead of |
3011 | -- an error in that case, as this likely corresponds | |
3012 | -- to deactivated code. | |
3013 | ||
3014 | Bad_Value (Warn => SPARK_Mode = On); | |
3015 | ||
3016 | -- In GNATprove mode, we enable the range check so that | |
3017 | -- GNATprove will issue a message if it cannot be proved. | |
f4f2bf51 | 3018 | |
3019 | if GNATprove_Mode then | |
3020 | Enable_Range_Check (Expr); | |
f4f2bf51 | 3021 | end if; |
3022 | ||
9dfe12ae | 3023 | return; |
3024 | end if; | |
3025 | ||
3026 | -- Otherwise determine range of value | |
3027 | ||
54022749 | 3028 | if Is_Discrete_Type (Etype (Expr)) then |
552d7cbc | 3029 | Determine_Range |
3030 | (Expr, OK, Lo, Hi, Assume_Valid => True); | |
54022749 | 3031 | |
3032 | -- When converting a float to an integer type, determine the | |
3033 | -- range in real first, and then convert the bounds using | |
3034 | -- UR_To_Uint which correctly rounds away from zero when | |
3035 | -- half way between two integers, as required by normal | |
3036 | -- Ada 95 rounding semantics. It is only possible because | |
3037 | -- analysis in GNATprove rules out the possibility of a NaN | |
3038 | -- or infinite value. | |
3039 | ||
3040 | elsif GNATprove_Mode | |
3041 | and then Is_Floating_Point_Type (Etype (Expr)) | |
3042 | then | |
3043 | declare | |
54022749 | 3044 | Hir : Ureal; |
552d7cbc | 3045 | Lor : Ureal; |
3046 | ||
54022749 | 3047 | begin |
552d7cbc | 3048 | Determine_Range_R |
3049 | (Expr, OK, Lor, Hir, Assume_Valid => True); | |
54022749 | 3050 | |
3051 | if OK then | |
3052 | Lo := UR_To_Uint (Lor); | |
3053 | Hi := UR_To_Uint (Hir); | |
3054 | end if; | |
3055 | end; | |
3056 | end if; | |
9dfe12ae | 3057 | |
3058 | if OK then | |
3059 | ||
3060 | -- If definitely in range, all OK | |
ee6ba406 | 3061 | |
ee6ba406 | 3062 | if Lo >= Lov and then Hi <= Hiv then |
3063 | return; | |
3064 | ||
9dfe12ae | 3065 | -- If definitely not in range, warn |
3066 | ||
ee6ba406 | 3067 | elsif Lov > Hi or else Hiv < Lo then |
3068 | Bad_Value; | |
3069 | return; | |
9dfe12ae | 3070 | |
3071 | -- Otherwise we don't know | |
3072 | ||
3073 | else | |
3074 | null; | |
ee6ba406 | 3075 | end if; |
9dfe12ae | 3076 | end if; |
3077 | end; | |
ee6ba406 | 3078 | end if; |
3079 | end; | |
3080 | end if; | |
3081 | ||
3082 | Int_Real := | |
3083 | Is_Floating_Point_Type (S_Typ) | |
3084 | or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int); | |
3085 | ||
3086 | -- Check if we can determine at compile time whether Expr is in the | |
9dfe12ae | 3087 | -- range of the target type. Note that if S_Typ is within the bounds |
3088 | -- of Target_Typ then this must be the case. This check is meaningful | |
3089 | -- only if this is not a conversion between integer and real types. | |
ee6ba406 | 3090 | |
3091 | if not Is_Unconstrained_Subscr_Ref | |
b40670e1 | 3092 | and then Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ) |
ee6ba406 | 3093 | and then |
7a1dabb3 | 3094 | (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int) |
ac5f5168 | 3095 | |
3096 | -- Also check if the expression itself is in the range of the | |
3097 | -- target type if it is a known at compile time value. We skip | |
3098 | -- this test if S_Typ is set since for OUT and IN OUT parameters | |
3099 | -- the Expr itself is not relevant to the checking. | |
3100 | ||
ee6ba406 | 3101 | or else |
ac5f5168 | 3102 | (No (Source_Typ) |
3103 | and then Is_In_Range (Expr, Target_Typ, | |
3104 | Assume_Valid => True, | |
3105 | Fixed_Int => Fixed_Int, | |
3106 | Int_Real => Int_Real))) | |
ee6ba406 | 3107 | then |
3108 | return; | |
3109 | ||
9c486805 | 3110 | elsif Is_Out_Of_Range (Expr, Target_Typ, |
3111 | Assume_Valid => True, | |
3112 | Fixed_Int => Fixed_Int, | |
3113 | Int_Real => Int_Real) | |
3114 | then | |
ee6ba406 | 3115 | Bad_Value; |
3116 | return; | |
3117 | ||
b40670e1 | 3118 | -- Floating-point case |
feff2f05 | 3119 | -- In the floating-point case, we only do range checks if the type is |
3120 | -- constrained. We definitely do NOT want range checks for unconstrained | |
29d958a7 | 3121 | -- types, since we want to have infinities, except when |
3122 | -- Check_Float_Overflow is set. | |
ee6ba406 | 3123 | |
9dfe12ae | 3124 | elsif Is_Floating_Point_Type (S_Typ) then |
29d958a7 | 3125 | if Is_Constrained (S_Typ) or else Check_Float_Overflow then |
9dfe12ae | 3126 | Enable_Range_Check (Expr); |
3127 | end if; | |
ee6ba406 | 3128 | |
9dfe12ae | 3129 | -- For all other cases we enable a range check unconditionally |
ee6ba406 | 3130 | |
3131 | else | |
3132 | Enable_Range_Check (Expr); | |
3133 | return; | |
3134 | end if; | |
ee6ba406 | 3135 | end Apply_Scalar_Range_Check; |
3136 | ||
3137 | ---------------------------------- | |
3138 | -- Apply_Selected_Length_Checks -- | |
3139 | ---------------------------------- | |
3140 | ||
3141 | procedure Apply_Selected_Length_Checks | |
3142 | (Ck_Node : Node_Id; | |
3143 | Target_Typ : Entity_Id; | |
3144 | Source_Typ : Entity_Id; | |
3145 | Do_Static : Boolean) | |
3146 | is | |
2b4f2458 | 3147 | Checks_On : constant Boolean := |
3148 | not Index_Checks_Suppressed (Target_Typ) | |
3149 | or else | |
3150 | not Length_Checks_Suppressed (Target_Typ); | |
3151 | ||
3152 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
3153 | ||
ee6ba406 | 3154 | Cond : Node_Id; |
ee6ba406 | 3155 | R_Cno : Node_Id; |
2b4f2458 | 3156 | R_Result : Check_Result; |
ee6ba406 | 3157 | |
3158 | begin | |
18cb6d78 | 3159 | -- Only apply checks when generating code |
f0d65dae | 3160 | |
4098232e | 3161 | -- Note: this means that we lose some useful warnings if the expander |
f0d65dae | 3162 | -- is not active. |
4098232e | 3163 | |
18cb6d78 | 3164 | if not Expander_Active then |
ee6ba406 | 3165 | return; |
3166 | end if; | |
3167 | ||
3168 | R_Result := | |
3169 | Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
3170 | ||
3171 | for J in 1 .. 2 loop | |
ee6ba406 | 3172 | R_Cno := R_Result (J); |
3173 | exit when No (R_Cno); | |
3174 | ||
3175 | -- A length check may mention an Itype which is attached to a | |
3176 | -- subsequent node. At the top level in a package this can cause | |
3177 | -- an order-of-elaboration problem, so we make sure that the itype | |
3178 | -- is referenced now. | |
3179 | ||
3180 | if Ekind (Current_Scope) = E_Package | |
3181 | and then Is_Compilation_Unit (Current_Scope) | |
3182 | then | |
3183 | Ensure_Defined (Target_Typ, Ck_Node); | |
3184 | ||
3185 | if Present (Source_Typ) then | |
3186 | Ensure_Defined (Source_Typ, Ck_Node); | |
3187 | ||
3188 | elsif Is_Itype (Etype (Ck_Node)) then | |
3189 | Ensure_Defined (Etype (Ck_Node), Ck_Node); | |
3190 | end if; | |
3191 | end if; | |
3192 | ||
feff2f05 | 3193 | -- If the item is a conditional raise of constraint error, then have |
3194 | -- a look at what check is being performed and ??? | |
ee6ba406 | 3195 | |
3196 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
3197 | and then Present (Condition (R_Cno)) | |
3198 | then | |
3199 | Cond := Condition (R_Cno); | |
3200 | ||
0577b0b1 | 3201 | -- Case where node does not now have a dynamic check |
ee6ba406 | 3202 | |
0577b0b1 | 3203 | if not Has_Dynamic_Length_Check (Ck_Node) then |
3204 | ||
3205 | -- If checks are on, just insert the check | |
3206 | ||
3207 | if Checks_On then | |
3208 | Insert_Action (Ck_Node, R_Cno); | |
3209 | ||
3210 | if not Do_Static then | |
3211 | Set_Has_Dynamic_Length_Check (Ck_Node); | |
3212 | end if; | |
3213 | ||
3214 | -- If checks are off, then analyze the length check after | |
3215 | -- temporarily attaching it to the tree in case the relevant | |
6fb3c314 | 3216 | -- condition can be evaluated at compile time. We still want a |
0577b0b1 | 3217 | -- compile time warning in this case. |
3218 | ||
3219 | else | |
3220 | Set_Parent (R_Cno, Ck_Node); | |
3221 | Analyze (R_Cno); | |
ee6ba406 | 3222 | end if; |
ee6ba406 | 3223 | end if; |
3224 | ||
3225 | -- Output a warning if the condition is known to be True | |
3226 | ||
3227 | if Is_Entity_Name (Cond) | |
3228 | and then Entity (Cond) = Standard_True | |
3229 | then | |
3230 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 3231 | (Ck_Node, "wrong length for array of}??", |
f15731c4 | 3232 | CE_Length_Check_Failed, |
ee6ba406 | 3233 | Ent => Target_Typ, |
3234 | Typ => Target_Typ); | |
3235 | ||
3236 | -- If we were only doing a static check, or if checks are not | |
3237 | -- on, then we want to delete the check, since it is not needed. | |
3238 | -- We do this by replacing the if statement by a null statement | |
3239 | ||
3240 | elsif Do_Static or else not Checks_On then | |
00c403ee | 3241 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 3242 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
3243 | end if; | |
3244 | ||
3245 | else | |
3246 | Install_Static_Check (R_Cno, Loc); | |
3247 | end if; | |
ee6ba406 | 3248 | end loop; |
ee6ba406 | 3249 | end Apply_Selected_Length_Checks; |
3250 | ||
3251 | --------------------------------- | |
3252 | -- Apply_Selected_Range_Checks -- | |
3253 | --------------------------------- | |
3254 | ||
3255 | procedure Apply_Selected_Range_Checks | |
3256 | (Ck_Node : Node_Id; | |
3257 | Target_Typ : Entity_Id; | |
3258 | Source_Typ : Entity_Id; | |
3259 | Do_Static : Boolean) | |
3260 | is | |
ee6ba406 | 3261 | Checks_On : constant Boolean := |
f9bcba0d | 3262 | not Index_Checks_Suppressed (Target_Typ) |
5372d110 | 3263 | or else |
3264 | not Range_Checks_Suppressed (Target_Typ); | |
f9bcba0d | 3265 | |
2b4f2458 | 3266 | Loc : constant Source_Ptr := Sloc (Ck_Node); |
3267 | ||
f9bcba0d | 3268 | Cond : Node_Id; |
3269 | R_Cno : Node_Id; | |
3270 | R_Result : Check_Result; | |
ee6ba406 | 3271 | |
3272 | begin | |
f0d65dae | 3273 | -- Only apply checks when generating code. In GNATprove mode, we do not |
3274 | -- apply the checks, but we still call Selected_Range_Checks to possibly | |
3275 | -- issue errors on SPARK code when a run-time error can be detected at | |
3276 | -- compile time. | |
3277 | ||
3278 | if not GNATprove_Mode then | |
3279 | if not Expander_Active or not Checks_On then | |
3280 | return; | |
3281 | end if; | |
ee6ba406 | 3282 | end if; |
3283 | ||
3284 | R_Result := | |
3285 | Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
3286 | ||
f0d65dae | 3287 | if GNATprove_Mode then |
3288 | return; | |
3289 | end if; | |
3290 | ||
ee6ba406 | 3291 | for J in 1 .. 2 loop |
ee6ba406 | 3292 | R_Cno := R_Result (J); |
3293 | exit when No (R_Cno); | |
3294 | ||
f9bcba0d | 3295 | -- The range check requires runtime evaluation. Depending on what its |
3296 | -- triggering condition is, the check may be converted into a compile | |
3297 | -- time constraint check. | |
ee6ba406 | 3298 | |
3299 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
3300 | and then Present (Condition (R_Cno)) | |
3301 | then | |
3302 | Cond := Condition (R_Cno); | |
3303 | ||
f9bcba0d | 3304 | -- Insert the range check before the related context. Note that |
3305 | -- this action analyses the triggering condition. | |
ee6ba406 | 3306 | |
f9bcba0d | 3307 | Insert_Action (Ck_Node, R_Cno); |
3308 | ||
3309 | -- This old code doesn't make sense, why is the context flagged as | |
3310 | -- requiring dynamic range checks now in the middle of generating | |
3311 | -- them ??? | |
3312 | ||
3313 | if not Do_Static then | |
3314 | Set_Has_Dynamic_Range_Check (Ck_Node); | |
ee6ba406 | 3315 | end if; |
3316 | ||
f9bcba0d | 3317 | -- The triggering condition evaluates to True, the range check |
3318 | -- can be converted into a compile time constraint check. | |
ee6ba406 | 3319 | |
3320 | if Is_Entity_Name (Cond) | |
3321 | and then Entity (Cond) = Standard_True | |
3322 | then | |
feff2f05 | 3323 | -- Since an N_Range is technically not an expression, we have |
3324 | -- to set one of the bounds to C_E and then just flag the | |
3325 | -- N_Range. The warning message will point to the lower bound | |
3326 | -- and complain about a range, which seems OK. | |
ee6ba406 | 3327 | |
3328 | if Nkind (Ck_Node) = N_Range then | |
3329 | Apply_Compile_Time_Constraint_Error | |
5372d110 | 3330 | (Low_Bound (Ck_Node), |
3331 | "static range out of bounds of}??", | |
f15731c4 | 3332 | CE_Range_Check_Failed, |
ee6ba406 | 3333 | Ent => Target_Typ, |
3334 | Typ => Target_Typ); | |
3335 | ||
3336 | Set_Raises_Constraint_Error (Ck_Node); | |
3337 | ||
3338 | else | |
3339 | Apply_Compile_Time_Constraint_Error | |
5372d110 | 3340 | (Ck_Node, |
1581f2d7 | 3341 | "static value out of range of}??", |
f15731c4 | 3342 | CE_Range_Check_Failed, |
ee6ba406 | 3343 | Ent => Target_Typ, |
3344 | Typ => Target_Typ); | |
3345 | end if; | |
3346 | ||
3347 | -- If we were only doing a static check, or if checks are not | |
3348 | -- on, then we want to delete the check, since it is not needed. | |
3349 | -- We do this by replacing the if statement by a null statement | |
3350 | ||
3fabf0ca | 3351 | elsif Do_Static then |
00c403ee | 3352 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 3353 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
3354 | end if; | |
3355 | ||
4ee78e36 | 3356 | -- The range check raises Constraint_Error explicitly |
f9bcba0d | 3357 | |
ee6ba406 | 3358 | else |
3359 | Install_Static_Check (R_Cno, Loc); | |
3360 | end if; | |
ee6ba406 | 3361 | end loop; |
ee6ba406 | 3362 | end Apply_Selected_Range_Checks; |
3363 | ||
3364 | ------------------------------- | |
3365 | -- Apply_Static_Length_Check -- | |
3366 | ------------------------------- | |
3367 | ||
3368 | procedure Apply_Static_Length_Check | |
3369 | (Expr : Node_Id; | |
3370 | Target_Typ : Entity_Id; | |
3371 | Source_Typ : Entity_Id := Empty) | |
3372 | is | |
3373 | begin | |
3374 | Apply_Selected_Length_Checks | |
3375 | (Expr, Target_Typ, Source_Typ, Do_Static => True); | |
3376 | end Apply_Static_Length_Check; | |
3377 | ||
3378 | ------------------------------------- | |
3379 | -- Apply_Subscript_Validity_Checks -- | |
3380 | ------------------------------------- | |
3381 | ||
3382 | procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is | |
3383 | Sub : Node_Id; | |
3384 | ||
3385 | begin | |
3386 | pragma Assert (Nkind (Expr) = N_Indexed_Component); | |
3387 | ||
3388 | -- Loop through subscripts | |
3389 | ||
3390 | Sub := First (Expressions (Expr)); | |
3391 | while Present (Sub) loop | |
3392 | ||
feff2f05 | 3393 | -- Check one subscript. Note that we do not worry about enumeration |
3394 | -- type with holes, since we will convert the value to a Pos value | |
3395 | -- for the subscript, and that convert will do the necessary validity | |
3396 | -- check. | |
ee6ba406 | 3397 | |
3398 | Ensure_Valid (Sub, Holes_OK => True); | |
3399 | ||
3400 | -- Move to next subscript | |
3401 | ||
3402 | Sub := Next (Sub); | |
3403 | end loop; | |
3404 | end Apply_Subscript_Validity_Checks; | |
3405 | ||
3406 | ---------------------------------- | |
3407 | -- Apply_Type_Conversion_Checks -- | |
3408 | ---------------------------------- | |
3409 | ||
3410 | procedure Apply_Type_Conversion_Checks (N : Node_Id) is | |
3411 | Target_Type : constant Entity_Id := Etype (N); | |
3412 | Target_Base : constant Entity_Id := Base_Type (Target_Type); | |
9dfe12ae | 3413 | Expr : constant Node_Id := Expression (N); |
f4532fe1 | 3414 | |
3415 | Expr_Type : constant Entity_Id := Underlying_Type (Etype (Expr)); | |
141d591a | 3416 | -- Note: if Etype (Expr) is a private type without discriminants, its |
3417 | -- full view might have discriminants with defaults, so we need the | |
3418 | -- full view here to retrieve the constraints. | |
ee6ba406 | 3419 | |
3420 | begin | |
3421 | if Inside_A_Generic then | |
3422 | return; | |
3423 | ||
f15731c4 | 3424 | -- Skip these checks if serious errors detected, there are some nasty |
ee6ba406 | 3425 | -- situations of incomplete trees that blow things up. |
3426 | ||
f15731c4 | 3427 | elsif Serious_Errors_Detected > 0 then |
ee6ba406 | 3428 | return; |
3429 | ||
ea822fd4 | 3430 | -- Never generate discriminant checks for Unchecked_Union types |
3431 | ||
3432 | elsif Present (Expr_Type) | |
3433 | and then Is_Unchecked_Union (Expr_Type) | |
3434 | then | |
3435 | return; | |
3436 | ||
feff2f05 | 3437 | -- Scalar type conversions of the form Target_Type (Expr) require a |
3438 | -- range check if we cannot be sure that Expr is in the base type of | |
3439 | -- Target_Typ and also that Expr is in the range of Target_Typ. These | |
3440 | -- are not quite the same condition from an implementation point of | |
3441 | -- view, but clearly the second includes the first. | |
ee6ba406 | 3442 | |
3443 | elsif Is_Scalar_Type (Target_Type) then | |
3444 | declare | |
3445 | Conv_OK : constant Boolean := Conversion_OK (N); | |
feff2f05 | 3446 | -- If the Conversion_OK flag on the type conversion is set and no |
ea822fd4 | 3447 | -- floating-point type is involved in the type conversion then |
3448 | -- fixed-point values must be read as integral values. | |
ee6ba406 | 3449 | |
5329ca64 | 3450 | Float_To_Int : constant Boolean := |
b6341c67 | 3451 | Is_Floating_Point_Type (Expr_Type) |
3452 | and then Is_Integer_Type (Target_Type); | |
5329ca64 | 3453 | |
ee6ba406 | 3454 | begin |
ee6ba406 | 3455 | if not Overflow_Checks_Suppressed (Target_Base) |
0df9d43f | 3456 | and then not Overflow_Checks_Suppressed (Target_Type) |
e254d721 | 3457 | and then not |
7a1dabb3 | 3458 | In_Subrange_Of (Expr_Type, Target_Base, Fixed_Int => Conv_OK) |
5329ca64 | 3459 | and then not Float_To_Int |
ee6ba406 | 3460 | then |
4642b679 | 3461 | -- A small optimization: the attribute 'Pos applied to an |
c59f2b2d | 3462 | -- enumeration type has a known range, even though its type is |
3463 | -- Universal_Integer. So in numeric conversions it is usually | |
3464 | -- within range of the target integer type. Use the static | |
3465 | -- bounds of the base types to check. Disable this optimization | |
3466 | -- in case of a generic formal discrete type, because we don't | |
3467 | -- necessarily know the upper bound yet. | |
259716a0 | 3468 | |
3469 | if Nkind (Expr) = N_Attribute_Reference | |
3470 | and then Attribute_Name (Expr) = Name_Pos | |
3471 | and then Is_Enumeration_Type (Etype (Prefix (Expr))) | |
c59f2b2d | 3472 | and then not Is_Generic_Type (Etype (Prefix (Expr))) |
259716a0 | 3473 | and then Is_Integer_Type (Target_Type) |
3474 | then | |
3475 | declare | |
4642b679 | 3476 | Enum_T : constant Entity_Id := |
3477 | Root_Type (Etype (Prefix (Expr))); | |
3478 | Int_T : constant Entity_Id := Base_Type (Target_Type); | |
3479 | Last_I : constant Uint := | |
3480 | Intval (High_Bound (Scalar_Range (Int_T))); | |
3481 | Last_E : Uint; | |
259716a0 | 3482 | |
3483 | begin | |
4642b679 | 3484 | -- Character types have no explicit literals, so we use |
259716a0 | 3485 | -- the known number of characters in the type. |
3486 | ||
3487 | if Root_Type (Enum_T) = Standard_Character then | |
3488 | Last_E := UI_From_Int (255); | |
3489 | ||
3490 | elsif Enum_T = Standard_Wide_Character | |
3491 | or else Enum_T = Standard_Wide_Wide_Character | |
3492 | then | |
3493 | Last_E := UI_From_Int (65535); | |
3494 | ||
3495 | else | |
4642b679 | 3496 | Last_E := |
3497 | Enumeration_Pos | |
259716a0 | 3498 | (Entity (High_Bound (Scalar_Range (Enum_T)))); |
3499 | end if; | |
3500 | ||
3501 | if Last_E <= Last_I then | |
3502 | null; | |
3503 | ||
3504 | else | |
3505 | Activate_Overflow_Check (N); | |
3506 | end if; | |
3507 | end; | |
3508 | ||
3509 | else | |
3510 | Activate_Overflow_Check (N); | |
3511 | end if; | |
ee6ba406 | 3512 | end if; |
3513 | ||
3514 | if not Range_Checks_Suppressed (Target_Type) | |
3515 | and then not Range_Checks_Suppressed (Expr_Type) | |
3516 | then | |
54022749 | 3517 | if Float_To_Int |
3518 | and then not GNATprove_Mode | |
3519 | then | |
5329ca64 | 3520 | Apply_Float_Conversion_Check (Expr, Target_Type); |
3521 | else | |
3522 | Apply_Scalar_Range_Check | |
3523 | (Expr, Target_Type, Fixed_Int => Conv_OK); | |
798afddc | 3524 | |
3525 | -- If the target type has predicates, we need to indicate | |
ea822fd4 | 3526 | -- the need for a check, even if Determine_Range finds that |
3527 | -- the value is within bounds. This may be the case e.g for | |
3528 | -- a division with a constant denominator. | |
798afddc | 3529 | |
3530 | if Has_Predicates (Target_Type) then | |
3531 | Enable_Range_Check (Expr); | |
3532 | end if; | |
5329ca64 | 3533 | end if; |
ee6ba406 | 3534 | end if; |
3535 | end; | |
3536 | ||
3537 | elsif Comes_From_Source (N) | |
f40f9731 | 3538 | and then not Discriminant_Checks_Suppressed (Target_Type) |
ee6ba406 | 3539 | and then Is_Record_Type (Target_Type) |
3540 | and then Is_Derived_Type (Target_Type) | |
3541 | and then not Is_Tagged_Type (Target_Type) | |
3542 | and then not Is_Constrained (Target_Type) | |
9dfe12ae | 3543 | and then Present (Stored_Constraint (Target_Type)) |
ee6ba406 | 3544 | then |
141d591a | 3545 | -- An unconstrained derived type may have inherited discriminant. |
9dfe12ae | 3546 | -- Build an actual discriminant constraint list using the stored |
ee6ba406 | 3547 | -- constraint, to verify that the expression of the parent type |
ea822fd4 | 3548 | -- satisfies the constraints imposed by the (unconstrained) derived |
3549 | -- type. This applies to value conversions, not to view conversions | |
3550 | -- of tagged types. | |
ee6ba406 | 3551 | |
3552 | declare | |
9dfe12ae | 3553 | Loc : constant Source_Ptr := Sloc (N); |
3554 | Cond : Node_Id; | |
3555 | Constraint : Elmt_Id; | |
3556 | Discr_Value : Node_Id; | |
3557 | Discr : Entity_Id; | |
3558 | ||
3559 | New_Constraints : constant Elist_Id := New_Elmt_List; | |
3560 | Old_Constraints : constant Elist_Id := | |
b6341c67 | 3561 | Discriminant_Constraint (Expr_Type); |
ee6ba406 | 3562 | |
3563 | begin | |
9dfe12ae | 3564 | Constraint := First_Elmt (Stored_Constraint (Target_Type)); |
ee6ba406 | 3565 | while Present (Constraint) loop |
3566 | Discr_Value := Node (Constraint); | |
3567 | ||
3568 | if Is_Entity_Name (Discr_Value) | |
3569 | and then Ekind (Entity (Discr_Value)) = E_Discriminant | |
3570 | then | |
3571 | Discr := Corresponding_Discriminant (Entity (Discr_Value)); | |
3572 | ||
3573 | if Present (Discr) | |
3574 | and then Scope (Discr) = Base_Type (Expr_Type) | |
3575 | then | |
3576 | -- Parent is constrained by new discriminant. Obtain | |
feff2f05 | 3577 | -- Value of original discriminant in expression. If the |
3578 | -- new discriminant has been used to constrain more than | |
3579 | -- one of the stored discriminants, this will provide the | |
3580 | -- required consistency check. | |
ee6ba406 | 3581 | |
55868293 | 3582 | Append_Elmt |
3583 | (Make_Selected_Component (Loc, | |
3584 | Prefix => | |
9dfe12ae | 3585 | Duplicate_Subexpr_No_Checks |
3586 | (Expr, Name_Req => True), | |
ee6ba406 | 3587 | Selector_Name => |
3588 | Make_Identifier (Loc, Chars (Discr))), | |
55868293 | 3589 | New_Constraints); |
ee6ba406 | 3590 | |
3591 | else | |
3592 | -- Discriminant of more remote ancestor ??? | |
3593 | ||
3594 | return; | |
3595 | end if; | |
3596 | ||
feff2f05 | 3597 | -- Derived type definition has an explicit value for this |
3598 | -- stored discriminant. | |
ee6ba406 | 3599 | |
3600 | else | |
3601 | Append_Elmt | |
9dfe12ae | 3602 | (Duplicate_Subexpr_No_Checks (Discr_Value), |
3603 | New_Constraints); | |
ee6ba406 | 3604 | end if; |
3605 | ||
3606 | Next_Elmt (Constraint); | |
3607 | end loop; | |
3608 | ||
3609 | -- Use the unconstrained expression type to retrieve the | |
3610 | -- discriminants of the parent, and apply momentarily the | |
3611 | -- discriminant constraint synthesized above. | |
3612 | ||
3613 | Set_Discriminant_Constraint (Expr_Type, New_Constraints); | |
3614 | Cond := Build_Discriminant_Checks (Expr, Expr_Type); | |
3615 | Set_Discriminant_Constraint (Expr_Type, Old_Constraints); | |
3616 | ||
3617 | Insert_Action (N, | |
f15731c4 | 3618 | Make_Raise_Constraint_Error (Loc, |
3619 | Condition => Cond, | |
3620 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 3621 | end; |
3622 | ||
175a6969 | 3623 | -- For arrays, checks are set now, but conversions are applied during |
3624 | -- expansion, to take into accounts changes of representation. The | |
3625 | -- checks become range checks on the base type or length checks on the | |
3626 | -- subtype, depending on whether the target type is unconstrained or | |
8e802312 | 3627 | -- constrained. Note that the range check is put on the expression of a |
3628 | -- type conversion, while the length check is put on the type conversion | |
3629 | -- itself. | |
175a6969 | 3630 | |
3631 | elsif Is_Array_Type (Target_Type) then | |
3632 | if Is_Constrained (Target_Type) then | |
3633 | Set_Do_Length_Check (N); | |
3634 | else | |
3635 | Set_Do_Range_Check (Expr); | |
3636 | end if; | |
ee6ba406 | 3637 | end if; |
ee6ba406 | 3638 | end Apply_Type_Conversion_Checks; |
3639 | ||
3640 | ---------------------------------------------- | |
3641 | -- Apply_Universal_Integer_Attribute_Checks -- | |
3642 | ---------------------------------------------- | |
3643 | ||
3644 | procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is | |
3645 | Loc : constant Source_Ptr := Sloc (N); | |
3646 | Typ : constant Entity_Id := Etype (N); | |
3647 | ||
3648 | begin | |
3649 | if Inside_A_Generic then | |
3650 | return; | |
3651 | ||
3652 | -- Nothing to do if checks are suppressed | |
3653 | ||
3654 | elsif Range_Checks_Suppressed (Typ) | |
3655 | and then Overflow_Checks_Suppressed (Typ) | |
3656 | then | |
3657 | return; | |
3658 | ||
3659 | -- Nothing to do if the attribute does not come from source. The | |
3660 | -- internal attributes we generate of this type do not need checks, | |
3661 | -- and furthermore the attempt to check them causes some circular | |
3662 | -- elaboration orders when dealing with packed types. | |
3663 | ||
3664 | elsif not Comes_From_Source (N) then | |
3665 | return; | |
3666 | ||
9dfe12ae | 3667 | -- If the prefix is a selected component that depends on a discriminant |
3668 | -- the check may improperly expose a discriminant instead of using | |
3669 | -- the bounds of the object itself. Set the type of the attribute to | |
3670 | -- the base type of the context, so that a check will be imposed when | |
3671 | -- needed (e.g. if the node appears as an index). | |
3672 | ||
3673 | elsif Nkind (Prefix (N)) = N_Selected_Component | |
3674 | and then Ekind (Typ) = E_Signed_Integer_Subtype | |
3675 | and then Depends_On_Discriminant (Scalar_Range (Typ)) | |
3676 | then | |
3677 | Set_Etype (N, Base_Type (Typ)); | |
3678 | ||
feff2f05 | 3679 | -- Otherwise, replace the attribute node with a type conversion node |
3680 | -- whose expression is the attribute, retyped to universal integer, and | |
3681 | -- whose subtype mark is the target type. The call to analyze this | |
3682 | -- conversion will set range and overflow checks as required for proper | |
3683 | -- detection of an out of range value. | |
ee6ba406 | 3684 | |
3685 | else | |
3686 | Set_Etype (N, Universal_Integer); | |
3687 | Set_Analyzed (N, True); | |
3688 | ||
3689 | Rewrite (N, | |
3690 | Make_Type_Conversion (Loc, | |
3691 | Subtype_Mark => New_Occurrence_Of (Typ, Loc), | |
3692 | Expression => Relocate_Node (N))); | |
3693 | ||
3694 | Analyze_And_Resolve (N, Typ); | |
3695 | return; | |
3696 | end if; | |
ee6ba406 | 3697 | end Apply_Universal_Integer_Attribute_Checks; |
3698 | ||
07c191b0 | 3699 | ------------------------------------- |
3700 | -- Atomic_Synchronization_Disabled -- | |
3701 | ------------------------------------- | |
3702 | ||
3703 | -- Note: internally Disable/Enable_Atomic_Synchronization is implemented | |
3704 | -- using a bogus check called Atomic_Synchronization. This is to make it | |
3705 | -- more convenient to get exactly the same semantics as [Un]Suppress. | |
3706 | ||
3707 | function Atomic_Synchronization_Disabled (E : Entity_Id) return Boolean is | |
3708 | begin | |
b444f81d | 3709 | -- If debug flag d.e is set, always return False, i.e. all atomic sync |
3710 | -- looks enabled, since it is never disabled. | |
3711 | ||
3712 | if Debug_Flag_Dot_E then | |
3713 | return False; | |
3714 | ||
3715 | -- If debug flag d.d is set then always return True, i.e. all atomic | |
3716 | -- sync looks disabled, since it always tests True. | |
3717 | ||
3718 | elsif Debug_Flag_Dot_D then | |
3719 | return True; | |
3720 | ||
3721 | -- If entity present, then check result for that entity | |
3722 | ||
3723 | elsif Present (E) and then Checks_May_Be_Suppressed (E) then | |
07c191b0 | 3724 | return Is_Check_Suppressed (E, Atomic_Synchronization); |
b444f81d | 3725 | |
3726 | -- Otherwise result depends on current scope setting | |
3727 | ||
07c191b0 | 3728 | else |
fafc6b97 | 3729 | return Scope_Suppress.Suppress (Atomic_Synchronization); |
07c191b0 | 3730 | end if; |
3731 | end Atomic_Synchronization_Disabled; | |
3732 | ||
ee6ba406 | 3733 | ------------------------------- |
3734 | -- Build_Discriminant_Checks -- | |
3735 | ------------------------------- | |
3736 | ||
3737 | function Build_Discriminant_Checks | |
3738 | (N : Node_Id; | |
314a23b6 | 3739 | T_Typ : Entity_Id) return Node_Id |
ee6ba406 | 3740 | is |
3741 | Loc : constant Source_Ptr := Sloc (N); | |
3742 | Cond : Node_Id; | |
3743 | Disc : Elmt_Id; | |
3744 | Disc_Ent : Entity_Id; | |
9dfe12ae | 3745 | Dref : Node_Id; |
ee6ba406 | 3746 | Dval : Node_Id; |
3747 | ||
84d0d4a5 | 3748 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id; |
3749 | ||
3750 | ---------------------------------- | |
3751 | -- Aggregate_Discriminant_Value -- | |
3752 | ---------------------------------- | |
3753 | ||
3754 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id is | |
3755 | Assoc : Node_Id; | |
3756 | ||
3757 | begin | |
feff2f05 | 3758 | -- The aggregate has been normalized with named associations. We use |
3759 | -- the Chars field to locate the discriminant to take into account | |
3760 | -- discriminants in derived types, which carry the same name as those | |
3761 | -- in the parent. | |
84d0d4a5 | 3762 | |
3763 | Assoc := First (Component_Associations (N)); | |
3764 | while Present (Assoc) loop | |
3765 | if Chars (First (Choices (Assoc))) = Chars (Disc) then | |
3766 | return Expression (Assoc); | |
3767 | else | |
3768 | Next (Assoc); | |
3769 | end if; | |
3770 | end loop; | |
3771 | ||
3772 | -- Discriminant must have been found in the loop above | |
3773 | ||
3774 | raise Program_Error; | |
3775 | end Aggregate_Discriminant_Val; | |
3776 | ||
3777 | -- Start of processing for Build_Discriminant_Checks | |
3778 | ||
ee6ba406 | 3779 | begin |
84d0d4a5 | 3780 | -- Loop through discriminants evolving the condition |
3781 | ||
ee6ba406 | 3782 | Cond := Empty; |
3783 | Disc := First_Elmt (Discriminant_Constraint (T_Typ)); | |
3784 | ||
9dfe12ae | 3785 | -- For a fully private type, use the discriminants of the parent type |
ee6ba406 | 3786 | |
3787 | if Is_Private_Type (T_Typ) | |
3788 | and then No (Full_View (T_Typ)) | |
3789 | then | |
3790 | Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ))); | |
3791 | else | |
3792 | Disc_Ent := First_Discriminant (T_Typ); | |
3793 | end if; | |
3794 | ||
3795 | while Present (Disc) loop | |
ee6ba406 | 3796 | Dval := Node (Disc); |
3797 | ||
3798 | if Nkind (Dval) = N_Identifier | |
3799 | and then Ekind (Entity (Dval)) = E_Discriminant | |
3800 | then | |
3801 | Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc); | |
3802 | else | |
9dfe12ae | 3803 | Dval := Duplicate_Subexpr_No_Checks (Dval); |
ee6ba406 | 3804 | end if; |
3805 | ||
00f91aef | 3806 | -- If we have an Unchecked_Union node, we can infer the discriminants |
3807 | -- of the node. | |
9dfe12ae | 3808 | |
00f91aef | 3809 | if Is_Unchecked_Union (Base_Type (T_Typ)) then |
3810 | Dref := New_Copy ( | |
3811 | Get_Discriminant_Value ( | |
3812 | First_Discriminant (T_Typ), | |
3813 | T_Typ, | |
3814 | Stored_Constraint (T_Typ))); | |
3815 | ||
84d0d4a5 | 3816 | elsif Nkind (N) = N_Aggregate then |
3817 | Dref := | |
3818 | Duplicate_Subexpr_No_Checks | |
3819 | (Aggregate_Discriminant_Val (Disc_Ent)); | |
3820 | ||
00f91aef | 3821 | else |
3822 | Dref := | |
3823 | Make_Selected_Component (Loc, | |
20cf157b | 3824 | Prefix => |
00f91aef | 3825 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
20cf157b | 3826 | Selector_Name => Make_Identifier (Loc, Chars (Disc_Ent))); |
00f91aef | 3827 | |
3828 | Set_Is_In_Discriminant_Check (Dref); | |
3829 | end if; | |
9dfe12ae | 3830 | |
ee6ba406 | 3831 | Evolve_Or_Else (Cond, |
3832 | Make_Op_Ne (Loc, | |
20cf157b | 3833 | Left_Opnd => Dref, |
ee6ba406 | 3834 | Right_Opnd => Dval)); |
3835 | ||
3836 | Next_Elmt (Disc); | |
3837 | Next_Discriminant (Disc_Ent); | |
3838 | end loop; | |
3839 | ||
3840 | return Cond; | |
3841 | end Build_Discriminant_Checks; | |
3842 | ||
13dbf220 | 3843 | ------------------ |
3844 | -- Check_Needed -- | |
3845 | ------------------ | |
3846 | ||
3847 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean is | |
3848 | N : Node_Id; | |
3849 | P : Node_Id; | |
3850 | K : Node_Kind; | |
3851 | L : Node_Id; | |
3852 | R : Node_Id; | |
3853 | ||
9b2068d4 | 3854 | function Left_Expression (Op : Node_Id) return Node_Id; |
3855 | -- Return the relevant expression from the left operand of the given | |
3856 | -- short circuit form: this is LO itself, except if LO is a qualified | |
3857 | -- expression, a type conversion, or an expression with actions, in | |
3858 | -- which case this is Left_Expression (Expression (LO)). | |
3859 | ||
3860 | --------------------- | |
3861 | -- Left_Expression -- | |
3862 | --------------------- | |
3863 | ||
3864 | function Left_Expression (Op : Node_Id) return Node_Id is | |
3865 | LE : Node_Id := Left_Opnd (Op); | |
3866 | begin | |
20cf157b | 3867 | while Nkind_In (LE, N_Qualified_Expression, |
3868 | N_Type_Conversion, | |
3869 | N_Expression_With_Actions) | |
9b2068d4 | 3870 | loop |
3871 | LE := Expression (LE); | |
3872 | end loop; | |
3873 | ||
3874 | return LE; | |
3875 | end Left_Expression; | |
3876 | ||
3877 | -- Start of processing for Check_Needed | |
3878 | ||
13dbf220 | 3879 | begin |
3880 | -- Always check if not simple entity | |
3881 | ||
3882 | if Nkind (Nod) not in N_Has_Entity | |
3883 | or else not Comes_From_Source (Nod) | |
3884 | then | |
3885 | return True; | |
3886 | end if; | |
3887 | ||
3888 | -- Look up tree for short circuit | |
3889 | ||
3890 | N := Nod; | |
3891 | loop | |
3892 | P := Parent (N); | |
3893 | K := Nkind (P); | |
3894 | ||
7b17e51b | 3895 | -- Done if out of subexpression (note that we allow generated stuff |
3896 | -- such as itype declarations in this context, to keep the loop going | |
3897 | -- since we may well have generated such stuff in complex situations. | |
3898 | -- Also done if no parent (probably an error condition, but no point | |
39a0c1d3 | 3899 | -- in behaving nasty if we find it). |
7b17e51b | 3900 | |
3901 | if No (P) | |
3902 | or else (K not in N_Subexpr and then Comes_From_Source (P)) | |
3903 | then | |
13dbf220 | 3904 | return True; |
3905 | ||
7b17e51b | 3906 | -- Or/Or Else case, where test is part of the right operand, or is |
3907 | -- part of one of the actions associated with the right operand, and | |
3908 | -- the left operand is an equality test. | |
13dbf220 | 3909 | |
7b17e51b | 3910 | elsif K = N_Op_Or then |
13dbf220 | 3911 | exit when N = Right_Opnd (P) |
9b2068d4 | 3912 | and then Nkind (Left_Expression (P)) = N_Op_Eq; |
13dbf220 | 3913 | |
7b17e51b | 3914 | elsif K = N_Or_Else then |
3915 | exit when (N = Right_Opnd (P) | |
3916 | or else | |
3917 | (Is_List_Member (N) | |
3918 | and then List_Containing (N) = Actions (P))) | |
9b2068d4 | 3919 | and then Nkind (Left_Expression (P)) = N_Op_Eq; |
13dbf220 | 3920 | |
7b17e51b | 3921 | -- Similar test for the And/And then case, where the left operand |
3922 | -- is an inequality test. | |
3923 | ||
3924 | elsif K = N_Op_And then | |
13dbf220 | 3925 | exit when N = Right_Opnd (P) |
9b2068d4 | 3926 | and then Nkind (Left_Expression (P)) = N_Op_Ne; |
7b17e51b | 3927 | |
3928 | elsif K = N_And_Then then | |
3929 | exit when (N = Right_Opnd (P) | |
3930 | or else | |
3931 | (Is_List_Member (N) | |
20cf157b | 3932 | and then List_Containing (N) = Actions (P))) |
9b2068d4 | 3933 | and then Nkind (Left_Expression (P)) = N_Op_Ne; |
13dbf220 | 3934 | end if; |
3935 | ||
3936 | N := P; | |
3937 | end loop; | |
3938 | ||
3939 | -- If we fall through the loop, then we have a conditional with an | |
9b2068d4 | 3940 | -- appropriate test as its left operand, so look further. |
3941 | ||
3942 | L := Left_Expression (P); | |
3943 | ||
3944 | -- L is an "=" or "/=" operator: extract its operands | |
13dbf220 | 3945 | |
13dbf220 | 3946 | R := Right_Opnd (L); |
3947 | L := Left_Opnd (L); | |
3948 | ||
3949 | -- Left operand of test must match original variable | |
3950 | ||
20cf157b | 3951 | if Nkind (L) not in N_Has_Entity or else Entity (L) /= Entity (Nod) then |
13dbf220 | 3952 | return True; |
3953 | end if; | |
3954 | ||
2af58f67 | 3955 | -- Right operand of test must be key value (zero or null) |
13dbf220 | 3956 | |
3957 | case Check is | |
3958 | when Access_Check => | |
2af58f67 | 3959 | if not Known_Null (R) then |
13dbf220 | 3960 | return True; |
3961 | end if; | |
3962 | ||
3963 | when Division_Check => | |
3964 | if not Compile_Time_Known_Value (R) | |
3965 | or else Expr_Value (R) /= Uint_0 | |
3966 | then | |
3967 | return True; | |
3968 | end if; | |
2af58f67 | 3969 | |
3970 | when others => | |
3971 | raise Program_Error; | |
13dbf220 | 3972 | end case; |
3973 | ||
3974 | -- Here we have the optimizable case, warn if not short-circuited | |
3975 | ||
3976 | if K = N_Op_And or else K = N_Op_Or then | |
c4968aa2 | 3977 | Error_Msg_Warn := SPARK_Mode /= On; |
4098232e | 3978 | |
13dbf220 | 3979 | case Check is |
3980 | when Access_Check => | |
4098232e | 3981 | if GNATprove_Mode then |
3982 | Error_Msg_N | |
3983 | ("Constraint_Error might have been raised (access check)", | |
3984 | Parent (Nod)); | |
3985 | else | |
3986 | Error_Msg_N | |
3987 | ("Constraint_Error may be raised (access check)??", | |
3988 | Parent (Nod)); | |
3989 | end if; | |
3990 | ||
13dbf220 | 3991 | when Division_Check => |
4098232e | 3992 | if GNATprove_Mode then |
3993 | Error_Msg_N | |
3994 | ("Constraint_Error might have been raised (zero divide)", | |
3995 | Parent (Nod)); | |
3996 | else | |
3997 | Error_Msg_N | |
3998 | ("Constraint_Error may be raised (zero divide)??", | |
3999 | Parent (Nod)); | |
4000 | end if; | |
2af58f67 | 4001 | |
4002 | when others => | |
4003 | raise Program_Error; | |
13dbf220 | 4004 | end case; |
4005 | ||
4006 | if K = N_Op_And then | |
e977c0cf | 4007 | Error_Msg_N -- CODEFIX |
cb97ae5c | 4008 | ("use `AND THEN` instead of AND??", P); |
13dbf220 | 4009 | else |
e977c0cf | 4010 | Error_Msg_N -- CODEFIX |
cb97ae5c | 4011 | ("use `OR ELSE` instead of OR??", P); |
13dbf220 | 4012 | end if; |
4013 | ||
6fb3c314 | 4014 | -- If not short-circuited, we need the check |
13dbf220 | 4015 | |
4016 | return True; | |
4017 | ||
4018 | -- If short-circuited, we can omit the check | |
4019 | ||
4020 | else | |
4021 | return False; | |
4022 | end if; | |
4023 | end Check_Needed; | |
4024 | ||
ee6ba406 | 4025 | ----------------------------------- |
4026 | -- Check_Valid_Lvalue_Subscripts -- | |
4027 | ----------------------------------- | |
4028 | ||
4029 | procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is | |
4030 | begin | |
4031 | -- Skip this if range checks are suppressed | |
4032 | ||
4033 | if Range_Checks_Suppressed (Etype (Expr)) then | |
4034 | return; | |
4035 | ||
feff2f05 | 4036 | -- Only do this check for expressions that come from source. We assume |
4037 | -- that expander generated assignments explicitly include any necessary | |
4038 | -- checks. Note that this is not just an optimization, it avoids | |
39a0c1d3 | 4039 | -- infinite recursions. |
ee6ba406 | 4040 | |
4041 | elsif not Comes_From_Source (Expr) then | |
4042 | return; | |
4043 | ||
4044 | -- For a selected component, check the prefix | |
4045 | ||
4046 | elsif Nkind (Expr) = N_Selected_Component then | |
4047 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
4048 | return; | |
4049 | ||
4050 | -- Case of indexed component | |
4051 | ||
4052 | elsif Nkind (Expr) = N_Indexed_Component then | |
4053 | Apply_Subscript_Validity_Checks (Expr); | |
4054 | ||
feff2f05 | 4055 | -- Prefix may itself be or contain an indexed component, and these |
4056 | -- subscripts need checking as well. | |
ee6ba406 | 4057 | |
4058 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
4059 | end if; | |
4060 | end Check_Valid_Lvalue_Subscripts; | |
4061 | ||
fa7497e8 | 4062 | ---------------------------------- |
4063 | -- Null_Exclusion_Static_Checks -- | |
4064 | ---------------------------------- | |
4065 | ||
e9998840 | 4066 | procedure Null_Exclusion_Static_Checks |
69733a9a | 4067 | (N : Node_Id; |
4068 | Comp : Node_Id := Empty; | |
4069 | Array_Comp : Boolean := False) | |
e9998840 | 4070 | is |
b1e656fb | 4071 | Has_Null : constant Boolean := Has_Null_Exclusion (N); |
4072 | Kind : constant Node_Kind := Nkind (N); | |
4073 | Error_Nod : Node_Id; | |
4074 | Expr : Node_Id; | |
4075 | Typ : Entity_Id; | |
fa7497e8 | 4076 | |
13dbf220 | 4077 | begin |
0577b0b1 | 4078 | pragma Assert |
b1e656fb | 4079 | (Nkind_In (Kind, N_Component_Declaration, |
4080 | N_Discriminant_Specification, | |
4081 | N_Function_Specification, | |
4082 | N_Object_Declaration, | |
4083 | N_Parameter_Specification)); | |
0577b0b1 | 4084 | |
b1e656fb | 4085 | if Kind = N_Function_Specification then |
0577b0b1 | 4086 | Typ := Etype (Defining_Entity (N)); |
4087 | else | |
4088 | Typ := Etype (Defining_Identifier (N)); | |
4089 | end if; | |
fa7497e8 | 4090 | |
b1e656fb | 4091 | case Kind is |
13dbf220 | 4092 | when N_Component_Declaration => |
4093 | if Present (Access_Definition (Component_Definition (N))) then | |
b1e656fb | 4094 | Error_Nod := Component_Definition (N); |
13dbf220 | 4095 | else |
b1e656fb | 4096 | Error_Nod := Subtype_Indication (Component_Definition (N)); |
13dbf220 | 4097 | end if; |
5329ca64 | 4098 | |
0577b0b1 | 4099 | when N_Discriminant_Specification => |
b1e656fb | 4100 | Error_Nod := Discriminant_Type (N); |
0577b0b1 | 4101 | |
4102 | when N_Function_Specification => | |
b1e656fb | 4103 | Error_Nod := Result_Definition (N); |
0577b0b1 | 4104 | |
4105 | when N_Object_Declaration => | |
b1e656fb | 4106 | Error_Nod := Object_Definition (N); |
0577b0b1 | 4107 | |
4108 | when N_Parameter_Specification => | |
b1e656fb | 4109 | Error_Nod := Parameter_Type (N); |
0577b0b1 | 4110 | |
13dbf220 | 4111 | when others => |
4112 | raise Program_Error; | |
4113 | end case; | |
5329ca64 | 4114 | |
0577b0b1 | 4115 | if Has_Null then |
5329ca64 | 4116 | |
0577b0b1 | 4117 | -- Enforce legality rule 3.10 (13): A null exclusion can only be |
4118 | -- applied to an access [sub]type. | |
5329ca64 | 4119 | |
0577b0b1 | 4120 | if not Is_Access_Type (Typ) then |
503f7fd3 | 4121 | Error_Msg_N |
b1e656fb | 4122 | ("`NOT NULL` allowed only for an access type", Error_Nod); |
5329ca64 | 4123 | |
feff2f05 | 4124 | -- Enforce legality rule RM 3.10(14/1): A null exclusion can only |
0577b0b1 | 4125 | -- be applied to a [sub]type that does not exclude null already. |
4126 | ||
b1e656fb | 4127 | elsif Can_Never_Be_Null (Typ) and then Comes_From_Source (Typ) then |
503f7fd3 | 4128 | Error_Msg_NE |
00c403ee | 4129 | ("`NOT NULL` not allowed (& already excludes null)", |
b1e656fb | 4130 | Error_Nod, Typ); |
0577b0b1 | 4131 | end if; |
13dbf220 | 4132 | end if; |
5329ca64 | 4133 | |
cc60bd16 | 4134 | -- Check that null-excluding objects are always initialized, except for |
4135 | -- deferred constants, for which the expression will appear in the full | |
4136 | -- declaration. | |
13dbf220 | 4137 | |
b1e656fb | 4138 | if Kind = N_Object_Declaration |
84d0d4a5 | 4139 | and then No (Expression (N)) |
cc60bd16 | 4140 | and then not Constant_Present (N) |
feff2f05 | 4141 | and then not No_Initialization (N) |
13dbf220 | 4142 | then |
e9998840 | 4143 | if Present (Comp) then |
4144 | ||
b1ff36e7 | 4145 | -- Specialize the warning message to indicate that we are dealing |
e9998840 | 4146 | -- with an uninitialized composite object that has a defaulted |
4147 | -- null-excluding component. | |
4148 | ||
4149 | Error_Msg_Name_1 := Chars (Defining_Identifier (Comp)); | |
4150 | Error_Msg_Name_2 := Chars (Defining_Identifier (N)); | |
4151 | ||
69733a9a | 4152 | Discard_Node |
4153 | (Compile_Time_Constraint_Error | |
4154 | (N => N, | |
4155 | Msg => | |
4156 | "(Ada 2005) null-excluding component % of object % must " | |
4157 | & "be initialized??", | |
4158 | Ent => Defining_Identifier (Comp))); | |
4159 | ||
4160 | -- This is a case of an array with null-excluding components, so | |
4161 | -- indicate that in the warning. | |
4162 | ||
4163 | elsif Array_Comp then | |
4164 | Discard_Node | |
4165 | (Compile_Time_Constraint_Error | |
4166 | (N => N, | |
4167 | Msg => | |
4168 | "(Ada 2005) null-excluding array components must " | |
4169 | & "be initialized??", | |
4170 | Ent => Defining_Identifier (N))); | |
4171 | ||
4172 | -- Normal case of object of a null-excluding access type | |
b1ff36e7 | 4173 | |
e9998840 | 4174 | else |
69733a9a | 4175 | -- Add an expression that assigns null. This node is needed by |
4176 | -- Apply_Compile_Time_Constraint_Error, which will replace this | |
4177 | -- with a Constraint_Error node. | |
4178 | ||
4179 | Set_Expression (N, Make_Null (Sloc (N))); | |
4180 | Set_Etype (Expression (N), Etype (Defining_Identifier (N))); | |
4181 | ||
e9998840 | 4182 | Apply_Compile_Time_Constraint_Error |
4183 | (N => Expression (N), | |
4184 | Msg => | |
4185 | "(Ada 2005) null-excluding objects must be initialized??", | |
4186 | Reason => CE_Null_Not_Allowed); | |
4187 | end if; | |
13dbf220 | 4188 | end if; |
5329ca64 | 4189 | |
cc60bd16 | 4190 | -- Check that a null-excluding component, formal or object is not being |
4191 | -- assigned a null value. Otherwise generate a warning message and | |
2c145f84 | 4192 | -- replace Expression (N) by an N_Constraint_Error node. |
13dbf220 | 4193 | |
b1e656fb | 4194 | if Kind /= N_Function_Specification then |
0577b0b1 | 4195 | Expr := Expression (N); |
5329ca64 | 4196 | |
2af58f67 | 4197 | if Present (Expr) and then Known_Null (Expr) then |
b1e656fb | 4198 | case Kind is |
99378362 | 4199 | when N_Component_Declaration |
4200 | | N_Discriminant_Specification | |
4201 | => | |
7189d17f | 4202 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 4203 | (N => Expr, |
99378362 | 4204 | Msg => |
4205 | "(Ada 2005) null not allowed in null-excluding " | |
4206 | & "components??", | |
0577b0b1 | 4207 | Reason => CE_Null_Not_Allowed); |
5329ca64 | 4208 | |
0577b0b1 | 4209 | when N_Object_Declaration => |
7189d17f | 4210 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 4211 | (N => Expr, |
99378362 | 4212 | Msg => |
4213 | "(Ada 2005) null not allowed in null-excluding " | |
4214 | & "objects??", | |
0577b0b1 | 4215 | Reason => CE_Null_Not_Allowed); |
5329ca64 | 4216 | |
0577b0b1 | 4217 | when N_Parameter_Specification => |
7189d17f | 4218 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 4219 | (N => Expr, |
99378362 | 4220 | Msg => |
4221 | "(Ada 2005) null not allowed in null-excluding " | |
4222 | & "formals??", | |
0577b0b1 | 4223 | Reason => CE_Null_Not_Allowed); |
13dbf220 | 4224 | |
4225 | when others => | |
4226 | null; | |
5329ca64 | 4227 | end case; |
4228 | end if; | |
0577b0b1 | 4229 | end if; |
fa7497e8 | 4230 | end Null_Exclusion_Static_Checks; |
4231 | ||
9dfe12ae | 4232 | ---------------------------------- |
4233 | -- Conditional_Statements_Begin -- | |
4234 | ---------------------------------- | |
4235 | ||
4236 | procedure Conditional_Statements_Begin is | |
4237 | begin | |
4238 | Saved_Checks_TOS := Saved_Checks_TOS + 1; | |
4239 | ||
feff2f05 | 4240 | -- If stack overflows, kill all checks, that way we know to simply reset |
4241 | -- the number of saved checks to zero on return. This should never occur | |
4242 | -- in practice. | |
9dfe12ae | 4243 | |
4244 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
4245 | Kill_All_Checks; | |
4246 | ||
feff2f05 | 4247 | -- In the normal case, we just make a new stack entry saving the current |
4248 | -- number of saved checks for a later restore. | |
9dfe12ae | 4249 | |
4250 | else | |
4251 | Saved_Checks_Stack (Saved_Checks_TOS) := Num_Saved_Checks; | |
4252 | ||
4253 | if Debug_Flag_CC then | |
4254 | w ("Conditional_Statements_Begin: Num_Saved_Checks = ", | |
4255 | Num_Saved_Checks); | |
4256 | end if; | |
4257 | end if; | |
4258 | end Conditional_Statements_Begin; | |
4259 | ||
4260 | -------------------------------- | |
4261 | -- Conditional_Statements_End -- | |
4262 | -------------------------------- | |
4263 | ||
4264 | procedure Conditional_Statements_End is | |
4265 | begin | |
4266 | pragma Assert (Saved_Checks_TOS > 0); | |
4267 | ||
feff2f05 | 4268 | -- If the saved checks stack overflowed, then we killed all checks, so |
4269 | -- setting the number of saved checks back to zero is correct. This | |
4270 | -- should never occur in practice. | |
9dfe12ae | 4271 | |
4272 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
4273 | Num_Saved_Checks := 0; | |
4274 | ||
feff2f05 | 4275 | -- In the normal case, restore the number of saved checks from the top |
4276 | -- stack entry. | |
9dfe12ae | 4277 | |
4278 | else | |
4279 | Num_Saved_Checks := Saved_Checks_Stack (Saved_Checks_TOS); | |
20cf157b | 4280 | |
9dfe12ae | 4281 | if Debug_Flag_CC then |
4282 | w ("Conditional_Statements_End: Num_Saved_Checks = ", | |
4283 | Num_Saved_Checks); | |
4284 | end if; | |
4285 | end if; | |
4286 | ||
4287 | Saved_Checks_TOS := Saved_Checks_TOS - 1; | |
4288 | end Conditional_Statements_End; | |
4289 | ||
3cce7f32 | 4290 | ------------------------- |
4291 | -- Convert_From_Bignum -- | |
4292 | ------------------------- | |
4293 | ||
4294 | function Convert_From_Bignum (N : Node_Id) return Node_Id is | |
4295 | Loc : constant Source_Ptr := Sloc (N); | |
4296 | ||
4297 | begin | |
4298 | pragma Assert (Is_RTE (Etype (N), RE_Bignum)); | |
4299 | ||
4300 | -- Construct call From Bignum | |
4301 | ||
4302 | return | |
4303 | Make_Function_Call (Loc, | |
4304 | Name => | |
4305 | New_Occurrence_Of (RTE (RE_From_Bignum), Loc), | |
4306 | Parameter_Associations => New_List (Relocate_Node (N))); | |
4307 | end Convert_From_Bignum; | |
4308 | ||
4309 | ----------------------- | |
4310 | -- Convert_To_Bignum -- | |
4311 | ----------------------- | |
4312 | ||
4313 | function Convert_To_Bignum (N : Node_Id) return Node_Id is | |
4314 | Loc : constant Source_Ptr := Sloc (N); | |
4315 | ||
4316 | begin | |
0326b4d4 | 4317 | -- Nothing to do if Bignum already except call Relocate_Node |
3cce7f32 | 4318 | |
4319 | if Is_RTE (Etype (N), RE_Bignum) then | |
4320 | return Relocate_Node (N); | |
4321 | ||
21a55437 | 4322 | -- Otherwise construct call to To_Bignum, converting the operand to the |
4323 | -- required Long_Long_Integer form. | |
3cce7f32 | 4324 | |
4325 | else | |
4326 | pragma Assert (Is_Signed_Integer_Type (Etype (N))); | |
4327 | return | |
4328 | Make_Function_Call (Loc, | |
4329 | Name => | |
4330 | New_Occurrence_Of (RTE (RE_To_Bignum), Loc), | |
4331 | Parameter_Associations => New_List ( | |
4332 | Convert_To (Standard_Long_Long_Integer, Relocate_Node (N)))); | |
4333 | end if; | |
4334 | end Convert_To_Bignum; | |
4335 | ||
ee6ba406 | 4336 | --------------------- |
4337 | -- Determine_Range -- | |
4338 | --------------------- | |
4339 | ||
6af1bdbc | 4340 | Cache_Size : constant := 2 ** 10; |
ee6ba406 | 4341 | type Cache_Index is range 0 .. Cache_Size - 1; |
39a0c1d3 | 4342 | -- Determine size of below cache (power of 2 is more efficient) |
ee6ba406 | 4343 | |
7ac8c2b1 | 4344 | Determine_Range_Cache_N : array (Cache_Index) of Node_Id; |
4345 | Determine_Range_Cache_V : array (Cache_Index) of Boolean; | |
4346 | Determine_Range_Cache_Lo : array (Cache_Index) of Uint; | |
4347 | Determine_Range_Cache_Hi : array (Cache_Index) of Uint; | |
4348 | Determine_Range_Cache_Lo_R : array (Cache_Index) of Ureal; | |
4349 | Determine_Range_Cache_Hi_R : array (Cache_Index) of Ureal; | |
feff2f05 | 4350 | -- The above arrays are used to implement a small direct cache for |
7ac8c2b1 | 4351 | -- Determine_Range and Determine_Range_R calls. Because of the way these |
4352 | -- subprograms recursively traces subexpressions, and because overflow | |
4353 | -- checking calls the routine on the way up the tree, a quadratic behavior | |
4354 | -- can otherwise be encountered in large expressions. The cache entry for | |
4355 | -- node N is stored in the (N mod Cache_Size) entry, and can be validated | |
4356 | -- by checking the actual node value stored there. The Range_Cache_V array | |
4357 | -- records the setting of Assume_Valid for the cache entry. | |
ee6ba406 | 4358 | |
4359 | procedure Determine_Range | |
9c486805 | 4360 | (N : Node_Id; |
4361 | OK : out Boolean; | |
4362 | Lo : out Uint; | |
4363 | Hi : out Uint; | |
4364 | Assume_Valid : Boolean := False) | |
ee6ba406 | 4365 | is |
e254d721 | 4366 | Typ : Entity_Id := Etype (N); |
4367 | -- Type to use, may get reset to base type for possibly invalid entity | |
8880be85 | 4368 | |
4369 | Lo_Left : Uint; | |
4370 | Hi_Left : Uint; | |
4371 | -- Lo and Hi bounds of left operand | |
ee6ba406 | 4372 | |
ee6ba406 | 4373 | Lo_Right : Uint; |
ee6ba406 | 4374 | Hi_Right : Uint; |
8880be85 | 4375 | -- Lo and Hi bounds of right (or only) operand |
4376 | ||
4377 | Bound : Node_Id; | |
4378 | -- Temp variable used to hold a bound node | |
4379 | ||
4380 | Hbound : Uint; | |
4381 | -- High bound of base type of expression | |
4382 | ||
4383 | Lor : Uint; | |
4384 | Hir : Uint; | |
4385 | -- Refined values for low and high bounds, after tightening | |
4386 | ||
4387 | OK1 : Boolean; | |
4388 | -- Used in lower level calls to indicate if call succeeded | |
4389 | ||
4390 | Cindex : Cache_Index; | |
4391 | -- Used to search cache | |
ee6ba406 | 4392 | |
094ed68e | 4393 | Btyp : Entity_Id; |
4394 | -- Base type | |
4395 | ||
ee6ba406 | 4396 | function OK_Operands return Boolean; |
4397 | -- Used for binary operators. Determines the ranges of the left and | |
4398 | -- right operands, and if they are both OK, returns True, and puts | |
341bd953 | 4399 | -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left. |
ee6ba406 | 4400 | |
4401 | ----------------- | |
4402 | -- OK_Operands -- | |
4403 | ----------------- | |
4404 | ||
4405 | function OK_Operands return Boolean is | |
4406 | begin | |
9c486805 | 4407 | Determine_Range |
4408 | (Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid); | |
ee6ba406 | 4409 | |
4410 | if not OK1 then | |
4411 | return False; | |
4412 | end if; | |
4413 | ||
9c486805 | 4414 | Determine_Range |
4415 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
ee6ba406 | 4416 | return OK1; |
4417 | end OK_Operands; | |
4418 | ||
4419 | -- Start of processing for Determine_Range | |
4420 | ||
4421 | begin | |
e12b2502 | 4422 | -- Prevent junk warnings by initializing range variables |
4423 | ||
4424 | Lo := No_Uint; | |
4425 | Hi := No_Uint; | |
4426 | Lor := No_Uint; | |
4427 | Hir := No_Uint; | |
4428 | ||
87bdc21d | 4429 | -- For temporary constants internally generated to remove side effects |
4430 | -- we must use the corresponding expression to determine the range of | |
e12b2502 | 4431 | -- the expression. But note that the expander can also generate |
4432 | -- constants in other cases, including deferred constants. | |
87bdc21d | 4433 | |
4434 | if Is_Entity_Name (N) | |
4435 | and then Nkind (Parent (Entity (N))) = N_Object_Declaration | |
4436 | and then Ekind (Entity (N)) = E_Constant | |
4437 | and then Is_Internal_Name (Chars (Entity (N))) | |
4438 | then | |
e12b2502 | 4439 | if Present (Expression (Parent (Entity (N)))) then |
4440 | Determine_Range | |
4441 | (Expression (Parent (Entity (N))), OK, Lo, Hi, Assume_Valid); | |
87bdc21d | 4442 | |
e12b2502 | 4443 | elsif Present (Full_View (Entity (N))) then |
4444 | Determine_Range | |
4445 | (Expression (Parent (Full_View (Entity (N)))), | |
4446 | OK, Lo, Hi, Assume_Valid); | |
ee6ba406 | 4447 | |
e12b2502 | 4448 | else |
4449 | OK := False; | |
4450 | end if; | |
4451 | return; | |
4452 | end if; | |
ee6ba406 | 4453 | |
a781c0fc | 4454 | -- If type is not defined, we can't determine its range |
ee6ba406 | 4455 | |
a781c0fc | 4456 | if No (Typ) |
4457 | ||
4458 | -- We don't deal with anything except discrete types | |
4459 | ||
4460 | or else not Is_Discrete_Type (Typ) | |
4461 | ||
4462 | -- Ignore type for which an error has been posted, since range in | |
4463 | -- this case may well be a bogosity deriving from the error. Also | |
4464 | -- ignore if error posted on the reference node. | |
4465 | ||
4466 | or else Error_Posted (N) or else Error_Posted (Typ) | |
ee6ba406 | 4467 | then |
4468 | OK := False; | |
4469 | return; | |
4470 | end if; | |
4471 | ||
4472 | -- For all other cases, we can determine the range | |
4473 | ||
4474 | OK := True; | |
4475 | ||
feff2f05 | 4476 | -- If value is compile time known, then the possible range is the one |
39a0c1d3 | 4477 | -- value that we know this expression definitely has. |
ee6ba406 | 4478 | |
4479 | if Compile_Time_Known_Value (N) then | |
4480 | Lo := Expr_Value (N); | |
4481 | Hi := Lo; | |
4482 | return; | |
4483 | end if; | |
4484 | ||
4485 | -- Return if already in the cache | |
4486 | ||
4487 | Cindex := Cache_Index (N mod Cache_Size); | |
4488 | ||
9c486805 | 4489 | if Determine_Range_Cache_N (Cindex) = N |
4490 | and then | |
4491 | Determine_Range_Cache_V (Cindex) = Assume_Valid | |
4492 | then | |
ee6ba406 | 4493 | Lo := Determine_Range_Cache_Lo (Cindex); |
4494 | Hi := Determine_Range_Cache_Hi (Cindex); | |
4495 | return; | |
4496 | end if; | |
4497 | ||
feff2f05 | 4498 | -- Otherwise, start by finding the bounds of the type of the expression, |
4499 | -- the value cannot be outside this range (if it is, then we have an | |
4500 | -- overflow situation, which is a separate check, we are talking here | |
4501 | -- only about the expression value). | |
ee6ba406 | 4502 | |
341bd953 | 4503 | -- First a check, never try to find the bounds of a generic type, since |
4504 | -- these bounds are always junk values, and it is only valid to look at | |
4505 | -- the bounds in an instance. | |
4506 | ||
4507 | if Is_Generic_Type (Typ) then | |
4508 | OK := False; | |
4509 | return; | |
4510 | end if; | |
4511 | ||
9c486805 | 4512 | -- First step, change to use base type unless we know the value is valid |
e254d721 | 4513 | |
9c486805 | 4514 | if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N))) |
4515 | or else Assume_No_Invalid_Values | |
4516 | or else Assume_Valid | |
e254d721 | 4517 | then |
9c486805 | 4518 | null; |
4519 | else | |
4520 | Typ := Underlying_Type (Base_Type (Typ)); | |
e254d721 | 4521 | end if; |
4522 | ||
094ed68e | 4523 | -- Retrieve the base type. Handle the case where the base type is a |
4524 | -- private enumeration type. | |
4525 | ||
4526 | Btyp := Base_Type (Typ); | |
4527 | ||
4528 | if Is_Private_Type (Btyp) and then Present (Full_View (Btyp)) then | |
4529 | Btyp := Full_View (Btyp); | |
4530 | end if; | |
4531 | ||
feff2f05 | 4532 | -- We use the actual bound unless it is dynamic, in which case use the |
4533 | -- corresponding base type bound if possible. If we can't get a bound | |
4534 | -- then we figure we can't determine the range (a peculiar case, that | |
4535 | -- perhaps cannot happen, but there is no point in bombing in this | |
4536 | -- optimization circuit. | |
8880be85 | 4537 | |
4538 | -- First the low bound | |
ee6ba406 | 4539 | |
4540 | Bound := Type_Low_Bound (Typ); | |
4541 | ||
4542 | if Compile_Time_Known_Value (Bound) then | |
4543 | Lo := Expr_Value (Bound); | |
4544 | ||
094ed68e | 4545 | elsif Compile_Time_Known_Value (Type_Low_Bound (Btyp)) then |
4546 | Lo := Expr_Value (Type_Low_Bound (Btyp)); | |
ee6ba406 | 4547 | |
4548 | else | |
4549 | OK := False; | |
4550 | return; | |
4551 | end if; | |
4552 | ||
8880be85 | 4553 | -- Now the high bound |
4554 | ||
ee6ba406 | 4555 | Bound := Type_High_Bound (Typ); |
4556 | ||
8880be85 | 4557 | -- We need the high bound of the base type later on, and this should |
4558 | -- always be compile time known. Again, it is not clear that this | |
4559 | -- can ever be false, but no point in bombing. | |
ee6ba406 | 4560 | |
094ed68e | 4561 | if Compile_Time_Known_Value (Type_High_Bound (Btyp)) then |
4562 | Hbound := Expr_Value (Type_High_Bound (Btyp)); | |
ee6ba406 | 4563 | Hi := Hbound; |
4564 | ||
4565 | else | |
4566 | OK := False; | |
4567 | return; | |
4568 | end if; | |
4569 | ||
feff2f05 | 4570 | -- If we have a static subtype, then that may have a tighter bound so |
4571 | -- use the upper bound of the subtype instead in this case. | |
8880be85 | 4572 | |
4573 | if Compile_Time_Known_Value (Bound) then | |
4574 | Hi := Expr_Value (Bound); | |
4575 | end if; | |
4576 | ||
feff2f05 | 4577 | -- We may be able to refine this value in certain situations. If any |
4578 | -- refinement is possible, then Lor and Hir are set to possibly tighter | |
4579 | -- bounds, and OK1 is set to True. | |
ee6ba406 | 4580 | |
4581 | case Nkind (N) is | |
4582 | ||
4583 | -- For unary plus, result is limited by range of operand | |
4584 | ||
4585 | when N_Op_Plus => | |
9c486805 | 4586 | Determine_Range |
4587 | (Right_Opnd (N), OK1, Lor, Hir, Assume_Valid); | |
ee6ba406 | 4588 | |
4589 | -- For unary minus, determine range of operand, and negate it | |
4590 | ||
4591 | when N_Op_Minus => | |
9c486805 | 4592 | Determine_Range |
4593 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
ee6ba406 | 4594 | |
4595 | if OK1 then | |
4596 | Lor := -Hi_Right; | |
4597 | Hir := -Lo_Right; | |
4598 | end if; | |
4599 | ||
4600 | -- For binary addition, get range of each operand and do the | |
4601 | -- addition to get the result range. | |
4602 | ||
4603 | when N_Op_Add => | |
4604 | if OK_Operands then | |
4605 | Lor := Lo_Left + Lo_Right; | |
4606 | Hir := Hi_Left + Hi_Right; | |
4607 | end if; | |
4608 | ||
feff2f05 | 4609 | -- Division is tricky. The only case we consider is where the right |
4610 | -- operand is a positive constant, and in this case we simply divide | |
4611 | -- the bounds of the left operand | |
ee6ba406 | 4612 | |
4613 | when N_Op_Divide => | |
4614 | if OK_Operands then | |
4615 | if Lo_Right = Hi_Right | |
4616 | and then Lo_Right > 0 | |
4617 | then | |
4618 | Lor := Lo_Left / Lo_Right; | |
4619 | Hir := Hi_Left / Lo_Right; | |
ee6ba406 | 4620 | else |
4621 | OK1 := False; | |
4622 | end if; | |
4623 | end if; | |
4624 | ||
feff2f05 | 4625 | -- For binary subtraction, get range of each operand and do the worst |
4626 | -- case subtraction to get the result range. | |
ee6ba406 | 4627 | |
4628 | when N_Op_Subtract => | |
4629 | if OK_Operands then | |
4630 | Lor := Lo_Left - Hi_Right; | |
4631 | Hir := Hi_Left - Lo_Right; | |
4632 | end if; | |
4633 | ||
feff2f05 | 4634 | -- For MOD, if right operand is a positive constant, then result must |
4635 | -- be in the allowable range of mod results. | |
ee6ba406 | 4636 | |
4637 | when N_Op_Mod => | |
4638 | if OK_Operands then | |
9dfe12ae | 4639 | if Lo_Right = Hi_Right |
4640 | and then Lo_Right /= 0 | |
4641 | then | |
ee6ba406 | 4642 | if Lo_Right > 0 then |
4643 | Lor := Uint_0; | |
4644 | Hir := Lo_Right - 1; | |
4645 | ||
9dfe12ae | 4646 | else -- Lo_Right < 0 |
ee6ba406 | 4647 | Lor := Lo_Right + 1; |
4648 | Hir := Uint_0; | |
4649 | end if; | |
4650 | ||
4651 | else | |
4652 | OK1 := False; | |
4653 | end if; | |
4654 | end if; | |
4655 | ||
feff2f05 | 4656 | -- For REM, if right operand is a positive constant, then result must |
4657 | -- be in the allowable range of mod results. | |
ee6ba406 | 4658 | |
4659 | when N_Op_Rem => | |
4660 | if OK_Operands then | |
99378362 | 4661 | if Lo_Right = Hi_Right and then Lo_Right /= 0 then |
ee6ba406 | 4662 | declare |
4663 | Dval : constant Uint := (abs Lo_Right) - 1; | |
4664 | ||
4665 | begin | |
4666 | -- The sign of the result depends on the sign of the | |
4667 | -- dividend (but not on the sign of the divisor, hence | |
4668 | -- the abs operation above). | |
4669 | ||
4670 | if Lo_Left < 0 then | |
4671 | Lor := -Dval; | |
4672 | else | |
4673 | Lor := Uint_0; | |
4674 | end if; | |
4675 | ||
4676 | if Hi_Left < 0 then | |
4677 | Hir := Uint_0; | |
4678 | else | |
4679 | Hir := Dval; | |
4680 | end if; | |
4681 | end; | |
4682 | ||
4683 | else | |
4684 | OK1 := False; | |
4685 | end if; | |
4686 | end if; | |
4687 | ||
4688 | -- Attribute reference cases | |
4689 | ||
4690 | when N_Attribute_Reference => | |
4691 | case Attribute_Name (N) is | |
4692 | ||
4693 | -- For Pos/Val attributes, we can refine the range using the | |
ddbf7f2e | 4694 | -- possible range of values of the attribute expression. |
ee6ba406 | 4695 | |
99378362 | 4696 | when Name_Pos |
4697 | | Name_Val | |
4698 | => | |
9c486805 | 4699 | Determine_Range |
4700 | (First (Expressions (N)), OK1, Lor, Hir, Assume_Valid); | |
ee6ba406 | 4701 | |
4702 | -- For Length attribute, use the bounds of the corresponding | |
4703 | -- index type to refine the range. | |
4704 | ||
4705 | when Name_Length => | |
4706 | declare | |
4707 | Atyp : Entity_Id := Etype (Prefix (N)); | |
4708 | Inum : Nat; | |
4709 | Indx : Node_Id; | |
4710 | ||
4711 | LL, LU : Uint; | |
4712 | UL, UU : Uint; | |
4713 | ||
4714 | begin | |
4715 | if Is_Access_Type (Atyp) then | |
4716 | Atyp := Designated_Type (Atyp); | |
4717 | end if; | |
4718 | ||
4719 | -- For string literal, we know exact value | |
4720 | ||
4721 | if Ekind (Atyp) = E_String_Literal_Subtype then | |
4722 | OK := True; | |
4723 | Lo := String_Literal_Length (Atyp); | |
4724 | Hi := String_Literal_Length (Atyp); | |
4725 | return; | |
4726 | end if; | |
4727 | ||
4728 | -- Otherwise check for expression given | |
4729 | ||
4730 | if No (Expressions (N)) then | |
4731 | Inum := 1; | |
4732 | else | |
4733 | Inum := | |
4734 | UI_To_Int (Expr_Value (First (Expressions (N)))); | |
4735 | end if; | |
4736 | ||
4737 | Indx := First_Index (Atyp); | |
4738 | for J in 2 .. Inum loop | |
4739 | Indx := Next_Index (Indx); | |
4740 | end loop; | |
4741 | ||
9116df93 | 4742 | -- If the index type is a formal type or derived from |
c8da6114 | 4743 | -- one, the bounds are not static. |
4744 | ||
4745 | if Is_Generic_Type (Root_Type (Etype (Indx))) then | |
4746 | OK := False; | |
4747 | return; | |
4748 | end if; | |
4749 | ||
ee6ba406 | 4750 | Determine_Range |
9c486805 | 4751 | (Type_Low_Bound (Etype (Indx)), OK1, LL, LU, |
4752 | Assume_Valid); | |
ee6ba406 | 4753 | |
4754 | if OK1 then | |
4755 | Determine_Range | |
9c486805 | 4756 | (Type_High_Bound (Etype (Indx)), OK1, UL, UU, |
4757 | Assume_Valid); | |
ee6ba406 | 4758 | |
4759 | if OK1 then | |
4760 | ||
4761 | -- The maximum value for Length is the biggest | |
4762 | -- possible gap between the values of the bounds. | |
4763 | -- But of course, this value cannot be negative. | |
4764 | ||
9c486805 | 4765 | Hir := UI_Max (Uint_0, UU - LL + 1); |
ee6ba406 | 4766 | |
4767 | -- For constrained arrays, the minimum value for | |
4768 | -- Length is taken from the actual value of the | |
9116df93 | 4769 | -- bounds, since the index will be exactly of this |
4770 | -- subtype. | |
ee6ba406 | 4771 | |
4772 | if Is_Constrained (Atyp) then | |
9c486805 | 4773 | Lor := UI_Max (Uint_0, UL - LU + 1); |
ee6ba406 | 4774 | |
4775 | -- For an unconstrained array, the minimum value | |
4776 | -- for length is always zero. | |
4777 | ||
4778 | else | |
4779 | Lor := Uint_0; | |
4780 | end if; | |
4781 | end if; | |
4782 | end if; | |
4783 | end; | |
4784 | ||
4785 | -- No special handling for other attributes | |
9116df93 | 4786 | -- Probably more opportunities exist here??? |
ee6ba406 | 4787 | |
4788 | when others => | |
4789 | OK1 := False; | |
4790 | ||
4791 | end case; | |
4792 | ||
ee6ba406 | 4793 | when N_Type_Conversion => |
54022749 | 4794 | |
4795 | -- For type conversion from one discrete type to another, we can | |
4796 | -- refine the range using the converted value. | |
4797 | ||
4798 | if Is_Discrete_Type (Etype (Expression (N))) then | |
4799 | Determine_Range (Expression (N), OK1, Lor, Hir, Assume_Valid); | |
4800 | ||
4801 | -- When converting a float to an integer type, determine the range | |
4802 | -- in real first, and then convert the bounds using UR_To_Uint | |
4803 | -- which correctly rounds away from zero when half way between two | |
4804 | -- integers, as required by normal Ada 95 rounding semantics. It | |
4805 | -- is only possible because analysis in GNATprove rules out the | |
4806 | -- possibility of a NaN or infinite value. | |
4807 | ||
4808 | elsif GNATprove_Mode | |
4809 | and then Is_Floating_Point_Type (Etype (Expression (N))) | |
4810 | then | |
4811 | declare | |
4812 | Lor_Real, Hir_Real : Ureal; | |
4813 | begin | |
4814 | Determine_Range_R (Expression (N), OK1, Lor_Real, Hir_Real, | |
4815 | Assume_Valid); | |
4816 | ||
4817 | if OK1 then | |
4818 | Lor := UR_To_Uint (Lor_Real); | |
4819 | Hir := UR_To_Uint (Hir_Real); | |
4820 | end if; | |
4821 | end; | |
4822 | ||
4823 | else | |
4824 | OK1 := False; | |
4825 | end if; | |
ee6ba406 | 4826 | |
4827 | -- Nothing special to do for all other expression kinds | |
4828 | ||
4829 | when others => | |
4830 | OK1 := False; | |
4831 | Lor := No_Uint; | |
4832 | Hir := No_Uint; | |
4833 | end case; | |
4834 | ||
9116df93 | 4835 | -- At this stage, if OK1 is true, then we know that the actual result of |
4836 | -- the computed expression is in the range Lor .. Hir. We can use this | |
4837 | -- to restrict the possible range of results. | |
ee6ba406 | 4838 | |
4839 | if OK1 then | |
4840 | ||
9116df93 | 4841 | -- If the refined value of the low bound is greater than the type |
7ac8c2b1 | 4842 | -- low bound, then reset it to the more restrictive value. However, |
9116df93 | 4843 | -- we do NOT do this for the case of a modular type where the |
4844 | -- possible upper bound on the value is above the base type high | |
4845 | -- bound, because that means the result could wrap. | |
ee6ba406 | 4846 | |
4847 | if Lor > Lo | |
9116df93 | 4848 | and then not (Is_Modular_Integer_Type (Typ) and then Hir > Hbound) |
ee6ba406 | 4849 | then |
4850 | Lo := Lor; | |
4851 | end if; | |
4852 | ||
9116df93 | 4853 | -- Similarly, if the refined value of the high bound is less than the |
4854 | -- value so far, then reset it to the more restrictive value. Again, | |
4855 | -- we do not do this if the refined low bound is negative for a | |
4856 | -- modular type, since this would wrap. | |
ee6ba406 | 4857 | |
4858 | if Hir < Hi | |
9116df93 | 4859 | and then not (Is_Modular_Integer_Type (Typ) and then Lor < Uint_0) |
ee6ba406 | 4860 | then |
4861 | Hi := Hir; | |
4862 | end if; | |
4863 | end if; | |
4864 | ||
4865 | -- Set cache entry for future call and we are all done | |
4866 | ||
4867 | Determine_Range_Cache_N (Cindex) := N; | |
9c486805 | 4868 | Determine_Range_Cache_V (Cindex) := Assume_Valid; |
ee6ba406 | 4869 | Determine_Range_Cache_Lo (Cindex) := Lo; |
4870 | Determine_Range_Cache_Hi (Cindex) := Hi; | |
4871 | return; | |
4872 | ||
9116df93 | 4873 | -- If any exception occurs, it means that we have some bug in the compiler, |
4874 | -- possibly triggered by a previous error, or by some unforeseen peculiar | |
ee6ba406 | 4875 | -- occurrence. However, this is only an optimization attempt, so there is |
4876 | -- really no point in crashing the compiler. Instead we just decide, too | |
4877 | -- bad, we can't figure out a range in this case after all. | |
4878 | ||
4879 | exception | |
4880 | when others => | |
4881 | ||
4882 | -- Debug flag K disables this behavior (useful for debugging) | |
4883 | ||
4884 | if Debug_Flag_K then | |
4885 | raise; | |
4886 | else | |
4887 | OK := False; | |
4888 | Lo := No_Uint; | |
4889 | Hi := No_Uint; | |
4890 | return; | |
4891 | end if; | |
ee6ba406 | 4892 | end Determine_Range; |
4893 | ||
7ac8c2b1 | 4894 | ----------------------- |
4895 | -- Determine_Range_R -- | |
4896 | ----------------------- | |
4897 | ||
4898 | procedure Determine_Range_R | |
4899 | (N : Node_Id; | |
4900 | OK : out Boolean; | |
4901 | Lo : out Ureal; | |
4902 | Hi : out Ureal; | |
4903 | Assume_Valid : Boolean := False) | |
4904 | is | |
4905 | Typ : Entity_Id := Etype (N); | |
4906 | -- Type to use, may get reset to base type for possibly invalid entity | |
4907 | ||
4908 | Lo_Left : Ureal; | |
4909 | Hi_Left : Ureal; | |
4910 | -- Lo and Hi bounds of left operand | |
4911 | ||
4912 | Lo_Right : Ureal; | |
4913 | Hi_Right : Ureal; | |
4914 | -- Lo and Hi bounds of right (or only) operand | |
4915 | ||
4916 | Bound : Node_Id; | |
4917 | -- Temp variable used to hold a bound node | |
4918 | ||
4919 | Hbound : Ureal; | |
4920 | -- High bound of base type of expression | |
4921 | ||
4922 | Lor : Ureal; | |
4923 | Hir : Ureal; | |
4924 | -- Refined values for low and high bounds, after tightening | |
4925 | ||
4926 | OK1 : Boolean; | |
4927 | -- Used in lower level calls to indicate if call succeeded | |
4928 | ||
4929 | Cindex : Cache_Index; | |
4930 | -- Used to search cache | |
4931 | ||
4932 | Btyp : Entity_Id; | |
4933 | -- Base type | |
4934 | ||
4935 | function OK_Operands return Boolean; | |
4936 | -- Used for binary operators. Determines the ranges of the left and | |
4937 | -- right operands, and if they are both OK, returns True, and puts | |
4938 | -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left. | |
4939 | ||
4940 | function Round_Machine (B : Ureal) return Ureal; | |
4941 | -- B is a real bound. Round it using mode Round_Even. | |
4942 | ||
4943 | ----------------- | |
4944 | -- OK_Operands -- | |
4945 | ----------------- | |
4946 | ||
4947 | function OK_Operands return Boolean is | |
4948 | begin | |
4949 | Determine_Range_R | |
4950 | (Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid); | |
4951 | ||
4952 | if not OK1 then | |
4953 | return False; | |
4954 | end if; | |
4955 | ||
4956 | Determine_Range_R | |
4957 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
4958 | return OK1; | |
4959 | end OK_Operands; | |
4960 | ||
4961 | ------------------- | |
4962 | -- Round_Machine -- | |
4963 | ------------------- | |
4964 | ||
4965 | function Round_Machine (B : Ureal) return Ureal is | |
4966 | begin | |
4967 | return Machine (Typ, B, Round_Even, N); | |
4968 | end Round_Machine; | |
4969 | ||
4970 | -- Start of processing for Determine_Range_R | |
4971 | ||
4972 | begin | |
4973 | -- Prevent junk warnings by initializing range variables | |
4974 | ||
4975 | Lo := No_Ureal; | |
4976 | Hi := No_Ureal; | |
4977 | Lor := No_Ureal; | |
4978 | Hir := No_Ureal; | |
4979 | ||
4980 | -- For temporary constants internally generated to remove side effects | |
4981 | -- we must use the corresponding expression to determine the range of | |
4982 | -- the expression. But note that the expander can also generate | |
4983 | -- constants in other cases, including deferred constants. | |
4984 | ||
4985 | if Is_Entity_Name (N) | |
4986 | and then Nkind (Parent (Entity (N))) = N_Object_Declaration | |
4987 | and then Ekind (Entity (N)) = E_Constant | |
4988 | and then Is_Internal_Name (Chars (Entity (N))) | |
4989 | then | |
4990 | if Present (Expression (Parent (Entity (N)))) then | |
4991 | Determine_Range_R | |
4992 | (Expression (Parent (Entity (N))), OK, Lo, Hi, Assume_Valid); | |
4993 | ||
4994 | elsif Present (Full_View (Entity (N))) then | |
4995 | Determine_Range_R | |
4996 | (Expression (Parent (Full_View (Entity (N)))), | |
4997 | OK, Lo, Hi, Assume_Valid); | |
4998 | ||
4999 | else | |
5000 | OK := False; | |
5001 | end if; | |
4c1c7f3f | 5002 | |
7ac8c2b1 | 5003 | return; |
5004 | end if; | |
5005 | ||
5006 | -- If type is not defined, we can't determine its range | |
5007 | ||
5008 | if No (Typ) | |
5009 | ||
5010 | -- We don't deal with anything except IEEE floating-point types | |
5011 | ||
5012 | or else not Is_Floating_Point_Type (Typ) | |
5013 | or else Float_Rep (Typ) /= IEEE_Binary | |
5014 | ||
5015 | -- Ignore type for which an error has been posted, since range in | |
5016 | -- this case may well be a bogosity deriving from the error. Also | |
5017 | -- ignore if error posted on the reference node. | |
5018 | ||
5019 | or else Error_Posted (N) or else Error_Posted (Typ) | |
5020 | then | |
5021 | OK := False; | |
5022 | return; | |
5023 | end if; | |
5024 | ||
5025 | -- For all other cases, we can determine the range | |
5026 | ||
5027 | OK := True; | |
5028 | ||
5029 | -- If value is compile time known, then the possible range is the one | |
5030 | -- value that we know this expression definitely has. | |
5031 | ||
5032 | if Compile_Time_Known_Value (N) then | |
5033 | Lo := Expr_Value_R (N); | |
5034 | Hi := Lo; | |
5035 | return; | |
5036 | end if; | |
5037 | ||
5038 | -- Return if already in the cache | |
5039 | ||
5040 | Cindex := Cache_Index (N mod Cache_Size); | |
5041 | ||
5042 | if Determine_Range_Cache_N (Cindex) = N | |
5043 | and then | |
5044 | Determine_Range_Cache_V (Cindex) = Assume_Valid | |
5045 | then | |
5046 | Lo := Determine_Range_Cache_Lo_R (Cindex); | |
5047 | Hi := Determine_Range_Cache_Hi_R (Cindex); | |
5048 | return; | |
5049 | end if; | |
5050 | ||
5051 | -- Otherwise, start by finding the bounds of the type of the expression, | |
5052 | -- the value cannot be outside this range (if it is, then we have an | |
5053 | -- overflow situation, which is a separate check, we are talking here | |
5054 | -- only about the expression value). | |
5055 | ||
5056 | -- First a check, never try to find the bounds of a generic type, since | |
5057 | -- these bounds are always junk values, and it is only valid to look at | |
5058 | -- the bounds in an instance. | |
5059 | ||
5060 | if Is_Generic_Type (Typ) then | |
5061 | OK := False; | |
5062 | return; | |
5063 | end if; | |
5064 | ||
5065 | -- First step, change to use base type unless we know the value is valid | |
5066 | ||
5067 | if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N))) | |
5068 | or else Assume_No_Invalid_Values | |
5069 | or else Assume_Valid | |
5070 | then | |
5071 | null; | |
5072 | else | |
5073 | Typ := Underlying_Type (Base_Type (Typ)); | |
5074 | end if; | |
5075 | ||
5076 | -- Retrieve the base type. Handle the case where the base type is a | |
5077 | -- private type. | |
5078 | ||
5079 | Btyp := Base_Type (Typ); | |
5080 | ||
5081 | if Is_Private_Type (Btyp) and then Present (Full_View (Btyp)) then | |
5082 | Btyp := Full_View (Btyp); | |
5083 | end if; | |
5084 | ||
5085 | -- We use the actual bound unless it is dynamic, in which case use the | |
5086 | -- corresponding base type bound if possible. If we can't get a bound | |
5087 | -- then we figure we can't determine the range (a peculiar case, that | |
5088 | -- perhaps cannot happen, but there is no point in bombing in this | |
5089 | -- optimization circuit). | |
5090 | ||
5091 | -- First the low bound | |
5092 | ||
5093 | Bound := Type_Low_Bound (Typ); | |
5094 | ||
5095 | if Compile_Time_Known_Value (Bound) then | |
5096 | Lo := Expr_Value_R (Bound); | |
5097 | ||
5098 | elsif Compile_Time_Known_Value (Type_Low_Bound (Btyp)) then | |
5099 | Lo := Expr_Value_R (Type_Low_Bound (Btyp)); | |
5100 | ||
5101 | else | |
5102 | OK := False; | |
5103 | return; | |
5104 | end if; | |
5105 | ||
5106 | -- Now the high bound | |
5107 | ||
5108 | Bound := Type_High_Bound (Typ); | |
5109 | ||
5110 | -- We need the high bound of the base type later on, and this should | |
5111 | -- always be compile time known. Again, it is not clear that this | |
5112 | -- can ever be false, but no point in bombing. | |
5113 | ||
5114 | if Compile_Time_Known_Value (Type_High_Bound (Btyp)) then | |
5115 | Hbound := Expr_Value_R (Type_High_Bound (Btyp)); | |
5116 | Hi := Hbound; | |
5117 | ||
5118 | else | |
5119 | OK := False; | |
5120 | return; | |
5121 | end if; | |
5122 | ||
5123 | -- If we have a static subtype, then that may have a tighter bound so | |
5124 | -- use the upper bound of the subtype instead in this case. | |
5125 | ||
5126 | if Compile_Time_Known_Value (Bound) then | |
5127 | Hi := Expr_Value_R (Bound); | |
5128 | end if; | |
5129 | ||
5130 | -- We may be able to refine this value in certain situations. If any | |
5131 | -- refinement is possible, then Lor and Hir are set to possibly tighter | |
5132 | -- bounds, and OK1 is set to True. | |
5133 | ||
5134 | case Nkind (N) is | |
5135 | ||
5136 | -- For unary plus, result is limited by range of operand | |
5137 | ||
5138 | when N_Op_Plus => | |
5139 | Determine_Range_R | |
5140 | (Right_Opnd (N), OK1, Lor, Hir, Assume_Valid); | |
5141 | ||
5142 | -- For unary minus, determine range of operand, and negate it | |
5143 | ||
5144 | when N_Op_Minus => | |
5145 | Determine_Range_R | |
5146 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
5147 | ||
5148 | if OK1 then | |
5149 | Lor := -Hi_Right; | |
5150 | Hir := -Lo_Right; | |
5151 | end if; | |
5152 | ||
5153 | -- For binary addition, get range of each operand and do the | |
5154 | -- addition to get the result range. | |
5155 | ||
5156 | when N_Op_Add => | |
5157 | if OK_Operands then | |
5158 | Lor := Round_Machine (Lo_Left + Lo_Right); | |
5159 | Hir := Round_Machine (Hi_Left + Hi_Right); | |
5160 | end if; | |
5161 | ||
5162 | -- For binary subtraction, get range of each operand and do the worst | |
5163 | -- case subtraction to get the result range. | |
5164 | ||
5165 | when N_Op_Subtract => | |
5166 | if OK_Operands then | |
5167 | Lor := Round_Machine (Lo_Left - Hi_Right); | |
5168 | Hir := Round_Machine (Hi_Left - Lo_Right); | |
5169 | end if; | |
5170 | ||
5171 | -- For multiplication, get range of each operand and do the | |
5172 | -- four multiplications to get the result range. | |
5173 | ||
5174 | when N_Op_Multiply => | |
5175 | if OK_Operands then | |
5176 | declare | |
5177 | M1 : constant Ureal := Round_Machine (Lo_Left * Lo_Right); | |
5178 | M2 : constant Ureal := Round_Machine (Lo_Left * Hi_Right); | |
5179 | M3 : constant Ureal := Round_Machine (Hi_Left * Lo_Right); | |
5180 | M4 : constant Ureal := Round_Machine (Hi_Left * Hi_Right); | |
552d7cbc | 5181 | |
7ac8c2b1 | 5182 | begin |
5183 | Lor := UR_Min (UR_Min (M1, M2), UR_Min (M3, M4)); | |
5184 | Hir := UR_Max (UR_Max (M1, M2), UR_Max (M3, M4)); | |
5185 | end; | |
5186 | end if; | |
5187 | ||
5188 | -- For division, consider separately the cases where the right | |
5189 | -- operand is positive or negative. Otherwise, the right operand | |
5190 | -- can be arbitrarily close to zero, so the result is likely to | |
5191 | -- be unbounded in one direction, do not attempt to compute it. | |
5192 | ||
5193 | when N_Op_Divide => | |
5194 | if OK_Operands then | |
5195 | ||
5196 | -- Right operand is positive | |
5197 | ||
5198 | if Lo_Right > Ureal_0 then | |
5199 | ||
5200 | -- If the low bound of the left operand is negative, obtain | |
5201 | -- the overall low bound by dividing it by the smallest | |
5202 | -- value of the right operand, and otherwise by the largest | |
5203 | -- value of the right operand. | |
5204 | ||
5205 | if Lo_Left < Ureal_0 then | |
5206 | Lor := Round_Machine (Lo_Left / Lo_Right); | |
5207 | else | |
5208 | Lor := Round_Machine (Lo_Left / Hi_Right); | |
5209 | end if; | |
5210 | ||
5211 | -- If the high bound of the left operand is negative, obtain | |
5212 | -- the overall high bound by dividing it by the largest | |
5213 | -- value of the right operand, and otherwise by the | |
5214 | -- smallest value of the right operand. | |
5215 | ||
5216 | if Hi_Left < Ureal_0 then | |
5217 | Hir := Round_Machine (Hi_Left / Hi_Right); | |
5218 | else | |
5219 | Hir := Round_Machine (Hi_Left / Lo_Right); | |
5220 | end if; | |
5221 | ||
5222 | -- Right operand is negative | |
5223 | ||
5224 | elsif Hi_Right < Ureal_0 then | |
5225 | ||
5226 | -- If the low bound of the left operand is negative, obtain | |
5227 | -- the overall low bound by dividing it by the largest | |
5228 | -- value of the right operand, and otherwise by the smallest | |
5229 | -- value of the right operand. | |
5230 | ||
5231 | if Lo_Left < Ureal_0 then | |
5232 | Lor := Round_Machine (Lo_Left / Hi_Right); | |
5233 | else | |
5234 | Lor := Round_Machine (Lo_Left / Lo_Right); | |
5235 | end if; | |
5236 | ||
5237 | -- If the high bound of the left operand is negative, obtain | |
5238 | -- the overall high bound by dividing it by the smallest | |
5239 | -- value of the right operand, and otherwise by the | |
5240 | -- largest value of the right operand. | |
5241 | ||
5242 | if Hi_Left < Ureal_0 then | |
5243 | Hir := Round_Machine (Hi_Left / Lo_Right); | |
5244 | else | |
5245 | Hir := Round_Machine (Hi_Left / Hi_Right); | |
5246 | end if; | |
5247 | ||
5248 | else | |
5249 | OK1 := False; | |
5250 | end if; | |
5251 | end if; | |
5252 | ||
7ac8c2b1 | 5253 | when N_Type_Conversion => |
3c5c732f | 5254 | |
5255 | -- For type conversion from one floating-point type to another, we | |
5256 | -- can refine the range using the converted value. | |
5257 | ||
5258 | if Is_Floating_Point_Type (Etype (Expression (N))) then | |
5259 | Determine_Range_R (Expression (N), OK1, Lor, Hir, Assume_Valid); | |
5260 | ||
5261 | -- When converting an integer to a floating-point type, determine | |
5262 | -- the range in integer first, and then convert the bounds. | |
5263 | ||
5264 | elsif Is_Discrete_Type (Etype (Expression (N))) then | |
5265 | declare | |
552d7cbc | 5266 | Hir_Int : Uint; |
5267 | Lor_Int : Uint; | |
5268 | ||
3c5c732f | 5269 | begin |
552d7cbc | 5270 | Determine_Range |
5271 | (Expression (N), OK1, Lor_Int, Hir_Int, Assume_Valid); | |
3c5c732f | 5272 | |
5273 | if OK1 then | |
5274 | Lor := Round_Machine (UR_From_Uint (Lor_Int)); | |
5275 | Hir := Round_Machine (UR_From_Uint (Hir_Int)); | |
5276 | end if; | |
5277 | end; | |
5278 | ||
5279 | else | |
5280 | OK1 := False; | |
5281 | end if; | |
7ac8c2b1 | 5282 | |
5283 | -- Nothing special to do for all other expression kinds | |
5284 | ||
5285 | when others => | |
5286 | OK1 := False; | |
5287 | Lor := No_Ureal; | |
5288 | Hir := No_Ureal; | |
5289 | end case; | |
5290 | ||
5291 | -- At this stage, if OK1 is true, then we know that the actual result of | |
5292 | -- the computed expression is in the range Lor .. Hir. We can use this | |
5293 | -- to restrict the possible range of results. | |
5294 | ||
5295 | if OK1 then | |
5296 | ||
5297 | -- If the refined value of the low bound is greater than the type | |
5298 | -- low bound, then reset it to the more restrictive value. | |
5299 | ||
5300 | if Lor > Lo then | |
5301 | Lo := Lor; | |
5302 | end if; | |
5303 | ||
5304 | -- Similarly, if the refined value of the high bound is less than the | |
5305 | -- value so far, then reset it to the more restrictive value. | |
5306 | ||
5307 | if Hir < Hi then | |
5308 | Hi := Hir; | |
5309 | end if; | |
5310 | end if; | |
5311 | ||
5312 | -- Set cache entry for future call and we are all done | |
5313 | ||
5314 | Determine_Range_Cache_N (Cindex) := N; | |
5315 | Determine_Range_Cache_V (Cindex) := Assume_Valid; | |
5316 | Determine_Range_Cache_Lo_R (Cindex) := Lo; | |
5317 | Determine_Range_Cache_Hi_R (Cindex) := Hi; | |
5318 | return; | |
5319 | ||
5320 | -- If any exception occurs, it means that we have some bug in the compiler, | |
5321 | -- possibly triggered by a previous error, or by some unforeseen peculiar | |
5322 | -- occurrence. However, this is only an optimization attempt, so there is | |
5323 | -- really no point in crashing the compiler. Instead we just decide, too | |
5324 | -- bad, we can't figure out a range in this case after all. | |
5325 | ||
5326 | exception | |
5327 | when others => | |
5328 | ||
5329 | -- Debug flag K disables this behavior (useful for debugging) | |
5330 | ||
5331 | if Debug_Flag_K then | |
5332 | raise; | |
5333 | else | |
5334 | OK := False; | |
5335 | Lo := No_Ureal; | |
5336 | Hi := No_Ureal; | |
5337 | return; | |
5338 | end if; | |
5339 | end Determine_Range_R; | |
5340 | ||
ee6ba406 | 5341 | ------------------------------------ |
5342 | -- Discriminant_Checks_Suppressed -- | |
5343 | ------------------------------------ | |
5344 | ||
5345 | function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5346 | begin | |
9dfe12ae | 5347 | if Present (E) then |
5348 | if Is_Unchecked_Union (E) then | |
5349 | return True; | |
5350 | elsif Checks_May_Be_Suppressed (E) then | |
5351 | return Is_Check_Suppressed (E, Discriminant_Check); | |
5352 | end if; | |
5353 | end if; | |
5354 | ||
fafc6b97 | 5355 | return Scope_Suppress.Suppress (Discriminant_Check); |
ee6ba406 | 5356 | end Discriminant_Checks_Suppressed; |
5357 | ||
5358 | -------------------------------- | |
5359 | -- Division_Checks_Suppressed -- | |
5360 | -------------------------------- | |
5361 | ||
5362 | function Division_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5363 | begin | |
9dfe12ae | 5364 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
5365 | return Is_Check_Suppressed (E, Division_Check); | |
5366 | else | |
fafc6b97 | 5367 | return Scope_Suppress.Suppress (Division_Check); |
9dfe12ae | 5368 | end if; |
ee6ba406 | 5369 | end Division_Checks_Suppressed; |
5370 | ||
fa771c05 | 5371 | -------------------------------------- |
5372 | -- Duplicated_Tag_Checks_Suppressed -- | |
5373 | -------------------------------------- | |
5374 | ||
5375 | function Duplicated_Tag_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5376 | begin | |
5377 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
5378 | return Is_Check_Suppressed (E, Duplicated_Tag_Check); | |
5379 | else | |
5380 | return Scope_Suppress.Suppress (Duplicated_Tag_Check); | |
5381 | end if; | |
5382 | end Duplicated_Tag_Checks_Suppressed; | |
5383 | ||
ee6ba406 | 5384 | ----------------------------------- |
5385 | -- Elaboration_Checks_Suppressed -- | |
5386 | ----------------------------------- | |
5387 | ||
5388 | function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5389 | begin | |
38f5559f | 5390 | -- The complication in this routine is that if we are in the dynamic |
5391 | -- model of elaboration, we also check All_Checks, since All_Checks | |
5392 | -- does not set Elaboration_Check explicitly. | |
5393 | ||
9dfe12ae | 5394 | if Present (E) then |
5395 | if Kill_Elaboration_Checks (E) then | |
5396 | return True; | |
38f5559f | 5397 | |
9dfe12ae | 5398 | elsif Checks_May_Be_Suppressed (E) then |
38f5559f | 5399 | if Is_Check_Suppressed (E, Elaboration_Check) then |
5400 | return True; | |
5401 | elsif Dynamic_Elaboration_Checks then | |
5402 | return Is_Check_Suppressed (E, All_Checks); | |
5403 | else | |
5404 | return False; | |
5405 | end if; | |
9dfe12ae | 5406 | end if; |
5407 | end if; | |
5408 | ||
fafc6b97 | 5409 | if Scope_Suppress.Suppress (Elaboration_Check) then |
38f5559f | 5410 | return True; |
5411 | elsif Dynamic_Elaboration_Checks then | |
fafc6b97 | 5412 | return Scope_Suppress.Suppress (All_Checks); |
38f5559f | 5413 | else |
5414 | return False; | |
5415 | end if; | |
ee6ba406 | 5416 | end Elaboration_Checks_Suppressed; |
5417 | ||
9dfe12ae | 5418 | --------------------------- |
5419 | -- Enable_Overflow_Check -- | |
5420 | --------------------------- | |
5421 | ||
5422 | procedure Enable_Overflow_Check (N : Node_Id) is | |
4c1c7f3f | 5423 | Typ : constant Entity_Id := Base_Type (Etype (N)); |
db415383 | 5424 | Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
3cce7f32 | 5425 | Chk : Nat; |
5426 | OK : Boolean; | |
5427 | Ent : Entity_Id; | |
5428 | Ofs : Uint; | |
5429 | Lo : Uint; | |
5430 | Hi : Uint; | |
ee6ba406 | 5431 | |
f3ccbbb3 | 5432 | Do_Ovflow_Check : Boolean; |
5433 | ||
ee6ba406 | 5434 | begin |
9dfe12ae | 5435 | if Debug_Flag_CC then |
5436 | w ("Enable_Overflow_Check for node ", Int (N)); | |
5437 | Write_Str (" Source location = "); | |
5438 | wl (Sloc (N)); | |
00c403ee | 5439 | pg (Union_Id (N)); |
ee6ba406 | 5440 | end if; |
ee6ba406 | 5441 | |
75209ec5 | 5442 | -- No check if overflow checks suppressed for type of node |
5443 | ||
0df9d43f | 5444 | if Overflow_Checks_Suppressed (Etype (N)) then |
75209ec5 | 5445 | return; |
5446 | ||
49260fa5 | 5447 | -- Nothing to do for unsigned integer types, which do not overflow |
5448 | ||
5449 | elsif Is_Modular_Integer_Type (Typ) then | |
5450 | return; | |
3cce7f32 | 5451 | end if; |
5452 | ||
0df9d43f | 5453 | -- This is the point at which processing for STRICT mode diverges |
21a55437 | 5454 | -- from processing for MINIMIZED/ELIMINATED modes. This divergence is |
5455 | -- probably more extreme that it needs to be, but what is going on here | |
5456 | -- is that when we introduced MINIMIZED/ELIMINATED modes, we wanted | |
0df9d43f | 5457 | -- to leave the processing for STRICT mode untouched. There were |
21a55437 | 5458 | -- two reasons for this. First it avoided any incompatible change of |
0df9d43f | 5459 | -- behavior. Second, it guaranteed that STRICT mode continued to be |
21a55437 | 5460 | -- legacy reliable. |
3cce7f32 | 5461 | |
0df9d43f | 5462 | -- The big difference is that in STRICT mode there is a fair amount of |
3cce7f32 | 5463 | -- circuitry to try to avoid setting the Do_Overflow_Check flag if we |
5464 | -- know that no check is needed. We skip all that in the two new modes, | |
5465 | -- since really overflow checking happens over a whole subtree, and we | |
5466 | -- do the corresponding optimizations later on when applying the checks. | |
5467 | ||
5468 | if Mode in Minimized_Or_Eliminated then | |
0df9d43f | 5469 | if not (Overflow_Checks_Suppressed (Etype (N))) |
5470 | and then not (Is_Entity_Name (N) | |
5471 | and then Overflow_Checks_Suppressed (Entity (N))) | |
5472 | then | |
5473 | Activate_Overflow_Check (N); | |
5474 | end if; | |
3cce7f32 | 5475 | |
5476 | if Debug_Flag_CC then | |
5477 | w ("Minimized/Eliminated mode"); | |
5478 | end if; | |
5479 | ||
5480 | return; | |
5481 | end if; | |
5482 | ||
0df9d43f | 5483 | -- Remainder of processing is for STRICT case, and is unchanged from |
691fe9e0 | 5484 | -- earlier versions preceding the addition of MINIMIZED/ELIMINATED. |
49260fa5 | 5485 | |
feff2f05 | 5486 | -- Nothing to do if the range of the result is known OK. We skip this |
5487 | -- for conversions, since the caller already did the check, and in any | |
5488 | -- case the condition for deleting the check for a type conversion is | |
cc60bd16 | 5489 | -- different. |
ee6ba406 | 5490 | |
3cce7f32 | 5491 | if Nkind (N) /= N_Type_Conversion then |
9c486805 | 5492 | Determine_Range (N, OK, Lo, Hi, Assume_Valid => True); |
ee6ba406 | 5493 | |
cc60bd16 | 5494 | -- Note in the test below that we assume that the range is not OK |
5495 | -- if a bound of the range is equal to that of the type. That's not | |
5496 | -- quite accurate but we do this for the following reasons: | |
ee6ba406 | 5497 | |
9dfe12ae | 5498 | -- a) The way that Determine_Range works, it will typically report |
5499 | -- the bounds of the value as being equal to the bounds of the | |
5500 | -- type, because it either can't tell anything more precise, or | |
5501 | -- does not think it is worth the effort to be more precise. | |
ee6ba406 | 5502 | |
9dfe12ae | 5503 | -- b) It is very unusual to have a situation in which this would |
5504 | -- generate an unnecessary overflow check (an example would be | |
5505 | -- a subtype with a range 0 .. Integer'Last - 1 to which the | |
cc60bd16 | 5506 | -- literal value one is added). |
ee6ba406 | 5507 | |
9dfe12ae | 5508 | -- c) The alternative is a lot of special casing in this routine |
5509 | -- which would partially duplicate Determine_Range processing. | |
ee6ba406 | 5510 | |
f3ccbbb3 | 5511 | if OK then |
5512 | Do_Ovflow_Check := True; | |
5513 | ||
5514 | -- Note that the following checks are quite deliberately > and < | |
5515 | -- rather than >= and <= as explained above. | |
5516 | ||
5517 | if Lo > Expr_Value (Type_Low_Bound (Typ)) | |
5518 | and then | |
5519 | Hi < Expr_Value (Type_High_Bound (Typ)) | |
5520 | then | |
5521 | Do_Ovflow_Check := False; | |
5522 | ||
5523 | -- Despite the comments above, it is worth dealing specially with | |
5524 | -- division specially. The only case where integer division can | |
5525 | -- overflow is (largest negative number) / (-1). So we will do | |
5526 | -- an extra range analysis to see if this is possible. | |
5527 | ||
5528 | elsif Nkind (N) = N_Op_Divide then | |
5529 | Determine_Range | |
5530 | (Left_Opnd (N), OK, Lo, Hi, Assume_Valid => True); | |
5531 | ||
5532 | if OK and then Lo > Expr_Value (Type_Low_Bound (Typ)) then | |
5533 | Do_Ovflow_Check := False; | |
5534 | ||
5535 | else | |
5536 | Determine_Range | |
5537 | (Right_Opnd (N), OK, Lo, Hi, Assume_Valid => True); | |
5538 | ||
5539 | if OK and then (Lo > Uint_Minus_1 | |
5540 | or else | |
5541 | Hi < Uint_Minus_1) | |
5542 | then | |
5543 | Do_Ovflow_Check := False; | |
5544 | end if; | |
5545 | end if; | |
9dfe12ae | 5546 | end if; |
5547 | ||
f3ccbbb3 | 5548 | -- If no overflow check required, we are done |
5549 | ||
5550 | if not Do_Ovflow_Check then | |
5551 | if Debug_Flag_CC then | |
5552 | w ("No overflow check required"); | |
5553 | end if; | |
5554 | ||
5555 | return; | |
5556 | end if; | |
9dfe12ae | 5557 | end if; |
5558 | end if; | |
5559 | ||
feff2f05 | 5560 | -- If not in optimizing mode, set flag and we are done. We are also done |
5561 | -- (and just set the flag) if the type is not a discrete type, since it | |
5562 | -- is not worth the effort to eliminate checks for other than discrete | |
5563 | -- types. In addition, we take this same path if we have stored the | |
5564 | -- maximum number of checks possible already (a very unlikely situation, | |
39a0c1d3 | 5565 | -- but we do not want to blow up). |
9dfe12ae | 5566 | |
5567 | if Optimization_Level = 0 | |
5568 | or else not Is_Discrete_Type (Etype (N)) | |
5569 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 5570 | then |
00c403ee | 5571 | Activate_Overflow_Check (N); |
9dfe12ae | 5572 | |
5573 | if Debug_Flag_CC then | |
5574 | w ("Optimization off"); | |
5575 | end if; | |
5576 | ||
ee6ba406 | 5577 | return; |
9dfe12ae | 5578 | end if; |
ee6ba406 | 5579 | |
9dfe12ae | 5580 | -- Otherwise evaluate and check the expression |
5581 | ||
5582 | Find_Check | |
5583 | (Expr => N, | |
5584 | Check_Type => 'O', | |
5585 | Target_Type => Empty, | |
5586 | Entry_OK => OK, | |
5587 | Check_Num => Chk, | |
5588 | Ent => Ent, | |
5589 | Ofs => Ofs); | |
5590 | ||
5591 | if Debug_Flag_CC then | |
5592 | w ("Called Find_Check"); | |
5593 | w (" OK = ", OK); | |
5594 | ||
5595 | if OK then | |
5596 | w (" Check_Num = ", Chk); | |
5597 | w (" Ent = ", Int (Ent)); | |
5598 | Write_Str (" Ofs = "); | |
5599 | pid (Ofs); | |
5600 | end if; | |
5601 | end if; | |
ee6ba406 | 5602 | |
9dfe12ae | 5603 | -- If check is not of form to optimize, then set flag and we are done |
5604 | ||
5605 | if not OK then | |
00c403ee | 5606 | Activate_Overflow_Check (N); |
ee6ba406 | 5607 | return; |
9dfe12ae | 5608 | end if; |
ee6ba406 | 5609 | |
9dfe12ae | 5610 | -- If check is already performed, then return without setting flag |
5611 | ||
5612 | if Chk /= 0 then | |
5613 | if Debug_Flag_CC then | |
5614 | w ("Check suppressed!"); | |
5615 | end if; | |
ee6ba406 | 5616 | |
ee6ba406 | 5617 | return; |
9dfe12ae | 5618 | end if; |
ee6ba406 | 5619 | |
9dfe12ae | 5620 | -- Here we will make a new entry for the new check |
5621 | ||
00c403ee | 5622 | Activate_Overflow_Check (N); |
9dfe12ae | 5623 | Num_Saved_Checks := Num_Saved_Checks + 1; |
5624 | Saved_Checks (Num_Saved_Checks) := | |
5625 | (Killed => False, | |
5626 | Entity => Ent, | |
5627 | Offset => Ofs, | |
5628 | Check_Type => 'O', | |
5629 | Target_Type => Empty); | |
5630 | ||
5631 | if Debug_Flag_CC then | |
5632 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
5633 | w (" Entity = ", Int (Ent)); | |
5634 | Write_Str (" Offset = "); | |
5635 | pid (Ofs); | |
5636 | w (" Check_Type = O"); | |
5637 | w (" Target_Type = Empty"); | |
5638 | end if; | |
ee6ba406 | 5639 | |
feff2f05 | 5640 | -- If we get an exception, then something went wrong, probably because of |
20cf157b | 5641 | -- an error in the structure of the tree due to an incorrect program. Or |
5642 | -- it may be a bug in the optimization circuit. In either case the safest | |
feff2f05 | 5643 | -- thing is simply to set the check flag unconditionally. |
9dfe12ae | 5644 | |
5645 | exception | |
5646 | when others => | |
00c403ee | 5647 | Activate_Overflow_Check (N); |
9dfe12ae | 5648 | |
5649 | if Debug_Flag_CC then | |
5650 | w (" exception occurred, overflow flag set"); | |
5651 | end if; | |
5652 | ||
5653 | return; | |
5654 | end Enable_Overflow_Check; | |
5655 | ||
5656 | ------------------------ | |
5657 | -- Enable_Range_Check -- | |
5658 | ------------------------ | |
5659 | ||
5660 | procedure Enable_Range_Check (N : Node_Id) is | |
5661 | Chk : Nat; | |
5662 | OK : Boolean; | |
5663 | Ent : Entity_Id; | |
5664 | Ofs : Uint; | |
5665 | Ttyp : Entity_Id; | |
5666 | P : Node_Id; | |
5667 | ||
5668 | begin | |
feff2f05 | 5669 | -- Return if unchecked type conversion with range check killed. In this |
39a0c1d3 | 5670 | -- case we never set the flag (that's what Kill_Range_Check is about). |
9dfe12ae | 5671 | |
5672 | if Nkind (N) = N_Unchecked_Type_Conversion | |
5673 | and then Kill_Range_Check (N) | |
ee6ba406 | 5674 | then |
5675 | return; | |
9dfe12ae | 5676 | end if; |
ee6ba406 | 5677 | |
55e8372b | 5678 | -- Do not set range check flag if parent is assignment statement or |
5679 | -- object declaration with Suppress_Assignment_Checks flag set | |
5680 | ||
5681 | if Nkind_In (Parent (N), N_Assignment_Statement, N_Object_Declaration) | |
5682 | and then Suppress_Assignment_Checks (Parent (N)) | |
5683 | then | |
5684 | return; | |
5685 | end if; | |
5686 | ||
0577b0b1 | 5687 | -- Check for various cases where we should suppress the range check |
5688 | ||
5689 | -- No check if range checks suppressed for type of node | |
5690 | ||
20cf157b | 5691 | if Present (Etype (N)) and then Range_Checks_Suppressed (Etype (N)) then |
0577b0b1 | 5692 | return; |
5693 | ||
5694 | -- No check if node is an entity name, and range checks are suppressed | |
5695 | -- for this entity, or for the type of this entity. | |
5696 | ||
5697 | elsif Is_Entity_Name (N) | |
5698 | and then (Range_Checks_Suppressed (Entity (N)) | |
20cf157b | 5699 | or else Range_Checks_Suppressed (Etype (Entity (N)))) |
0577b0b1 | 5700 | then |
5701 | return; | |
5702 | ||
5703 | -- No checks if index of array, and index checks are suppressed for | |
5704 | -- the array object or the type of the array. | |
5705 | ||
5706 | elsif Nkind (Parent (N)) = N_Indexed_Component then | |
5707 | declare | |
5708 | Pref : constant Node_Id := Prefix (Parent (N)); | |
5709 | begin | |
5710 | if Is_Entity_Name (Pref) | |
5711 | and then Index_Checks_Suppressed (Entity (Pref)) | |
5712 | then | |
5713 | return; | |
5714 | elsif Index_Checks_Suppressed (Etype (Pref)) then | |
5715 | return; | |
5716 | end if; | |
5717 | end; | |
5718 | end if; | |
5719 | ||
9dfe12ae | 5720 | -- Debug trace output |
ee6ba406 | 5721 | |
9dfe12ae | 5722 | if Debug_Flag_CC then |
5723 | w ("Enable_Range_Check for node ", Int (N)); | |
5724 | Write_Str (" Source location = "); | |
5725 | wl (Sloc (N)); | |
00c403ee | 5726 | pg (Union_Id (N)); |
9dfe12ae | 5727 | end if; |
5728 | ||
feff2f05 | 5729 | -- If not in optimizing mode, set flag and we are done. We are also done |
5730 | -- (and just set the flag) if the type is not a discrete type, since it | |
5731 | -- is not worth the effort to eliminate checks for other than discrete | |
5732 | -- types. In addition, we take this same path if we have stored the | |
5733 | -- maximum number of checks possible already (a very unlikely situation, | |
39a0c1d3 | 5734 | -- but we do not want to blow up). |
9dfe12ae | 5735 | |
5736 | if Optimization_Level = 0 | |
5737 | or else No (Etype (N)) | |
5738 | or else not Is_Discrete_Type (Etype (N)) | |
5739 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 5740 | then |
00c403ee | 5741 | Activate_Range_Check (N); |
9dfe12ae | 5742 | |
5743 | if Debug_Flag_CC then | |
5744 | w ("Optimization off"); | |
5745 | end if; | |
5746 | ||
ee6ba406 | 5747 | return; |
9dfe12ae | 5748 | end if; |
ee6ba406 | 5749 | |
9dfe12ae | 5750 | -- Otherwise find out the target type |
ee6ba406 | 5751 | |
9dfe12ae | 5752 | P := Parent (N); |
ee6ba406 | 5753 | |
9dfe12ae | 5754 | -- For assignment, use left side subtype |
5755 | ||
5756 | if Nkind (P) = N_Assignment_Statement | |
5757 | and then Expression (P) = N | |
5758 | then | |
5759 | Ttyp := Etype (Name (P)); | |
5760 | ||
5761 | -- For indexed component, use subscript subtype | |
5762 | ||
5763 | elsif Nkind (P) = N_Indexed_Component then | |
5764 | declare | |
5765 | Atyp : Entity_Id; | |
5766 | Indx : Node_Id; | |
5767 | Subs : Node_Id; | |
5768 | ||
5769 | begin | |
5770 | Atyp := Etype (Prefix (P)); | |
5771 | ||
5772 | if Is_Access_Type (Atyp) then | |
5773 | Atyp := Designated_Type (Atyp); | |
f07ea091 | 5774 | |
5775 | -- If the prefix is an access to an unconstrained array, | |
feff2f05 | 5776 | -- perform check unconditionally: it depends on the bounds of |
5777 | -- an object and we cannot currently recognize whether the test | |
5778 | -- may be redundant. | |
f07ea091 | 5779 | |
5780 | if not Is_Constrained (Atyp) then | |
00c403ee | 5781 | Activate_Range_Check (N); |
f07ea091 | 5782 | return; |
5783 | end if; | |
7189d17f | 5784 | |
31831d39 | 5785 | -- Ditto if prefix is simply an unconstrained array. We used |
5786 | -- to think this case was OK, if the prefix was not an explicit | |
5787 | -- dereference, but we have now seen a case where this is not | |
5788 | -- true, so it is safer to just suppress the optimization in this | |
5789 | -- case. The back end is getting better at eliminating redundant | |
5790 | -- checks in any case, so the loss won't be important. | |
7189d17f | 5791 | |
31831d39 | 5792 | elsif Is_Array_Type (Atyp) |
7189d17f | 5793 | and then not Is_Constrained (Atyp) |
5794 | then | |
00c403ee | 5795 | Activate_Range_Check (N); |
7189d17f | 5796 | return; |
9dfe12ae | 5797 | end if; |
5798 | ||
5799 | Indx := First_Index (Atyp); | |
5800 | Subs := First (Expressions (P)); | |
5801 | loop | |
5802 | if Subs = N then | |
5803 | Ttyp := Etype (Indx); | |
5804 | exit; | |
5805 | end if; | |
5806 | ||
5807 | Next_Index (Indx); | |
5808 | Next (Subs); | |
5809 | end loop; | |
5810 | end; | |
5811 | ||
5812 | -- For now, ignore all other cases, they are not so interesting | |
5813 | ||
5814 | else | |
5815 | if Debug_Flag_CC then | |
5816 | w (" target type not found, flag set"); | |
5817 | end if; | |
5818 | ||
00c403ee | 5819 | Activate_Range_Check (N); |
9dfe12ae | 5820 | return; |
5821 | end if; | |
5822 | ||
5823 | -- Evaluate and check the expression | |
5824 | ||
5825 | Find_Check | |
5826 | (Expr => N, | |
5827 | Check_Type => 'R', | |
5828 | Target_Type => Ttyp, | |
5829 | Entry_OK => OK, | |
5830 | Check_Num => Chk, | |
5831 | Ent => Ent, | |
5832 | Ofs => Ofs); | |
5833 | ||
5834 | if Debug_Flag_CC then | |
5835 | w ("Called Find_Check"); | |
5836 | w ("Target_Typ = ", Int (Ttyp)); | |
5837 | w (" OK = ", OK); | |
5838 | ||
5839 | if OK then | |
5840 | w (" Check_Num = ", Chk); | |
5841 | w (" Ent = ", Int (Ent)); | |
5842 | Write_Str (" Ofs = "); | |
5843 | pid (Ofs); | |
5844 | end if; | |
5845 | end if; | |
5846 | ||
5847 | -- If check is not of form to optimize, then set flag and we are done | |
5848 | ||
5849 | if not OK then | |
5850 | if Debug_Flag_CC then | |
5851 | w (" expression not of optimizable type, flag set"); | |
5852 | end if; | |
5853 | ||
00c403ee | 5854 | Activate_Range_Check (N); |
9dfe12ae | 5855 | return; |
5856 | end if; | |
5857 | ||
5858 | -- If check is already performed, then return without setting flag | |
5859 | ||
5860 | if Chk /= 0 then | |
5861 | if Debug_Flag_CC then | |
5862 | w ("Check suppressed!"); | |
5863 | end if; | |
5864 | ||
5865 | return; | |
5866 | end if; | |
5867 | ||
5868 | -- Here we will make a new entry for the new check | |
5869 | ||
00c403ee | 5870 | Activate_Range_Check (N); |
9dfe12ae | 5871 | Num_Saved_Checks := Num_Saved_Checks + 1; |
5872 | Saved_Checks (Num_Saved_Checks) := | |
5873 | (Killed => False, | |
5874 | Entity => Ent, | |
5875 | Offset => Ofs, | |
5876 | Check_Type => 'R', | |
5877 | Target_Type => Ttyp); | |
5878 | ||
5879 | if Debug_Flag_CC then | |
5880 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
5881 | w (" Entity = ", Int (Ent)); | |
5882 | Write_Str (" Offset = "); | |
5883 | pid (Ofs); | |
5884 | w (" Check_Type = R"); | |
5885 | w (" Target_Type = ", Int (Ttyp)); | |
00c403ee | 5886 | pg (Union_Id (Ttyp)); |
9dfe12ae | 5887 | end if; |
5888 | ||
feff2f05 | 5889 | -- If we get an exception, then something went wrong, probably because of |
5890 | -- an error in the structure of the tree due to an incorrect program. Or | |
5891 | -- it may be a bug in the optimization circuit. In either case the safest | |
5892 | -- thing is simply to set the check flag unconditionally. | |
9dfe12ae | 5893 | |
5894 | exception | |
5895 | when others => | |
00c403ee | 5896 | Activate_Range_Check (N); |
9dfe12ae | 5897 | |
5898 | if Debug_Flag_CC then | |
5899 | w (" exception occurred, range flag set"); | |
5900 | end if; | |
5901 | ||
5902 | return; | |
5903 | end Enable_Range_Check; | |
5904 | ||
5905 | ------------------ | |
5906 | -- Ensure_Valid -- | |
5907 | ------------------ | |
5908 | ||
aaec8d13 | 5909 | procedure Ensure_Valid |
5910 | (Expr : Node_Id; | |
5911 | Holes_OK : Boolean := False; | |
5912 | Related_Id : Entity_Id := Empty; | |
5913 | Is_Low_Bound : Boolean := False; | |
5914 | Is_High_Bound : Boolean := False) | |
5915 | is | |
9dfe12ae | 5916 | Typ : constant Entity_Id := Etype (Expr); |
5917 | ||
5918 | begin | |
5919 | -- Ignore call if we are not doing any validity checking | |
5920 | ||
5921 | if not Validity_Checks_On then | |
5922 | return; | |
5923 | ||
0577b0b1 | 5924 | -- Ignore call if range or validity checks suppressed on entity or type |
9dfe12ae | 5925 | |
0577b0b1 | 5926 | elsif Range_Or_Validity_Checks_Suppressed (Expr) then |
9dfe12ae | 5927 | return; |
5928 | ||
feff2f05 | 5929 | -- No check required if expression is from the expander, we assume the |
5930 | -- expander will generate whatever checks are needed. Note that this is | |
39a0c1d3 | 5931 | -- not just an optimization, it avoids infinite recursions. |
9dfe12ae | 5932 | |
5933 | -- Unchecked conversions must be checked, unless they are initialized | |
5934 | -- scalar values, as in a component assignment in an init proc. | |
5935 | ||
5936 | -- In addition, we force a check if Force_Validity_Checks is set | |
5937 | ||
5938 | elsif not Comes_From_Source (Expr) | |
5939 | and then not Force_Validity_Checks | |
5940 | and then (Nkind (Expr) /= N_Unchecked_Type_Conversion | |
5941 | or else Kill_Range_Check (Expr)) | |
5942 | then | |
5943 | return; | |
5944 | ||
5945 | -- No check required if expression is known to have valid value | |
5946 | ||
5947 | elsif Expr_Known_Valid (Expr) then | |
5948 | return; | |
5949 | ||
ea1f4b87 | 5950 | -- No check needed within a generated predicate function. Validity |
5951 | -- of input value will have been checked earlier. | |
5952 | ||
5953 | elsif Ekind (Current_Scope) = E_Function | |
5954 | and then Is_Predicate_Function (Current_Scope) | |
5955 | then | |
5956 | return; | |
5957 | ||
feff2f05 | 5958 | -- Ignore case of enumeration with holes where the flag is set not to |
5959 | -- worry about holes, since no special validity check is needed | |
9dfe12ae | 5960 | |
5961 | elsif Is_Enumeration_Type (Typ) | |
5962 | and then Has_Non_Standard_Rep (Typ) | |
5963 | and then Holes_OK | |
5964 | then | |
5965 | return; | |
5966 | ||
f2a06be9 | 5967 | -- No check required on the left-hand side of an assignment |
9dfe12ae | 5968 | |
5969 | elsif Nkind (Parent (Expr)) = N_Assignment_Statement | |
5970 | and then Expr = Name (Parent (Expr)) | |
5971 | then | |
5972 | return; | |
5973 | ||
6fb3c314 | 5974 | -- No check on a universal real constant. The context will eventually |
38f5559f | 5975 | -- convert it to a machine number for some target type, or report an |
5976 | -- illegality. | |
5977 | ||
5978 | elsif Nkind (Expr) = N_Real_Literal | |
5979 | and then Etype (Expr) = Universal_Real | |
5980 | then | |
5981 | return; | |
5982 | ||
6fb3c314 | 5983 | -- If the expression denotes a component of a packed boolean array, |
0577b0b1 | 5984 | -- no possible check applies. We ignore the old ACATS chestnuts that |
5985 | -- involve Boolean range True..True. | |
5986 | ||
5987 | -- Note: validity checks are generated for expressions that yield a | |
5988 | -- scalar type, when it is possible to create a value that is outside of | |
5989 | -- the type. If this is a one-bit boolean no such value exists. This is | |
5990 | -- an optimization, and it also prevents compiler blowing up during the | |
5991 | -- elaboration of improperly expanded packed array references. | |
5992 | ||
5993 | elsif Nkind (Expr) = N_Indexed_Component | |
5994 | and then Is_Bit_Packed_Array (Etype (Prefix (Expr))) | |
5995 | and then Root_Type (Etype (Expr)) = Standard_Boolean | |
5996 | then | |
5997 | return; | |
5998 | ||
737e8460 | 5999 | -- For an expression with actions, we want to insert the validity check |
6000 | -- on the final Expression. | |
6001 | ||
6002 | elsif Nkind (Expr) = N_Expression_With_Actions then | |
6003 | Ensure_Valid (Expression (Expr)); | |
6004 | return; | |
6005 | ||
9dfe12ae | 6006 | -- An annoying special case. If this is an out parameter of a scalar |
6007 | -- type, then the value is not going to be accessed, therefore it is | |
6008 | -- inappropriate to do any validity check at the call site. | |
6009 | ||
6010 | else | |
6011 | -- Only need to worry about scalar types | |
6012 | ||
6013 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 6014 | declare |
6015 | P : Node_Id; | |
6016 | N : Node_Id; | |
6017 | E : Entity_Id; | |
6018 | F : Entity_Id; | |
6019 | A : Node_Id; | |
6020 | L : List_Id; | |
6021 | ||
6022 | begin | |
6023 | -- Find actual argument (which may be a parameter association) | |
6024 | -- and the parent of the actual argument (the call statement) | |
6025 | ||
6026 | N := Expr; | |
6027 | P := Parent (Expr); | |
6028 | ||
6029 | if Nkind (P) = N_Parameter_Association then | |
6030 | N := P; | |
6031 | P := Parent (N); | |
6032 | end if; | |
6033 | ||
feff2f05 | 6034 | -- Only need to worry if we are argument of a procedure call |
6035 | -- since functions don't have out parameters. If this is an | |
6036 | -- indirect or dispatching call, get signature from the | |
6037 | -- subprogram type. | |
ee6ba406 | 6038 | |
6039 | if Nkind (P) = N_Procedure_Call_Statement then | |
6040 | L := Parameter_Associations (P); | |
9dfe12ae | 6041 | |
6042 | if Is_Entity_Name (Name (P)) then | |
6043 | E := Entity (Name (P)); | |
6044 | else | |
6045 | pragma Assert (Nkind (Name (P)) = N_Explicit_Dereference); | |
6046 | E := Etype (Name (P)); | |
6047 | end if; | |
ee6ba406 | 6048 | |
feff2f05 | 6049 | -- Only need to worry if there are indeed actuals, and if |
6050 | -- this could be a procedure call, otherwise we cannot get a | |
6051 | -- match (either we are not an argument, or the mode of the | |
6052 | -- formal is not OUT). This test also filters out the | |
6053 | -- generic case. | |
ee6ba406 | 6054 | |
20cf157b | 6055 | if Is_Non_Empty_List (L) and then Is_Subprogram (E) then |
6056 | ||
feff2f05 | 6057 | -- This is the loop through parameters, looking for an |
6058 | -- OUT parameter for which we are the argument. | |
ee6ba406 | 6059 | |
6060 | F := First_Formal (E); | |
6061 | A := First (L); | |
ee6ba406 | 6062 | while Present (F) loop |
6063 | if Ekind (F) = E_Out_Parameter and then A = N then | |
6064 | return; | |
6065 | end if; | |
6066 | ||
6067 | Next_Formal (F); | |
6068 | Next (A); | |
6069 | end loop; | |
6070 | end if; | |
6071 | end if; | |
6072 | end; | |
6073 | end if; | |
6074 | end if; | |
6075 | ||
fa6a6949 | 6076 | -- If this is a boolean expression, only its elementary operands need |
90a07d4c | 6077 | -- checking: if they are valid, a boolean or short-circuit operation |
6078 | -- with them will be valid as well. | |
784d4230 | 6079 | |
6080 | if Base_Type (Typ) = Standard_Boolean | |
7af38999 | 6081 | and then |
fa6a6949 | 6082 | (Nkind (Expr) in N_Op or else Nkind (Expr) in N_Short_Circuit) |
784d4230 | 6083 | then |
6084 | return; | |
6085 | end if; | |
6086 | ||
0577b0b1 | 6087 | -- If we fall through, a validity check is required |
ee6ba406 | 6088 | |
aaec8d13 | 6089 | Insert_Valid_Check (Expr, Related_Id, Is_Low_Bound, Is_High_Bound); |
ce7498d3 | 6090 | |
6091 | if Is_Entity_Name (Expr) | |
6092 | and then Safe_To_Capture_Value (Expr, Entity (Expr)) | |
6093 | then | |
6094 | Set_Is_Known_Valid (Entity (Expr)); | |
6095 | end if; | |
ee6ba406 | 6096 | end Ensure_Valid; |
6097 | ||
6098 | ---------------------- | |
6099 | -- Expr_Known_Valid -- | |
6100 | ---------------------- | |
6101 | ||
6102 | function Expr_Known_Valid (Expr : Node_Id) return Boolean is | |
6103 | Typ : constant Entity_Id := Etype (Expr); | |
6104 | ||
6105 | begin | |
feff2f05 | 6106 | -- Non-scalar types are always considered valid, since they never give |
6107 | -- rise to the issues of erroneous or bounded error behavior that are | |
6108 | -- the concern. In formal reference manual terms the notion of validity | |
6109 | -- only applies to scalar types. Note that even when packed arrays are | |
6110 | -- represented using modular types, they are still arrays semantically, | |
6111 | -- so they are also always valid (in particular, the unused bits can be | |
6112 | -- random rubbish without affecting the validity of the array value). | |
ee6ba406 | 6113 | |
a88a5773 | 6114 | if not Is_Scalar_Type (Typ) or else Is_Packed_Array_Impl_Type (Typ) then |
ee6ba406 | 6115 | return True; |
6116 | ||
6117 | -- If no validity checking, then everything is considered valid | |
6118 | ||
6119 | elsif not Validity_Checks_On then | |
6120 | return True; | |
6121 | ||
6122 | -- Floating-point types are considered valid unless floating-point | |
6123 | -- validity checks have been specifically turned on. | |
6124 | ||
6125 | elsif Is_Floating_Point_Type (Typ) | |
6126 | and then not Validity_Check_Floating_Point | |
6127 | then | |
6128 | return True; | |
6129 | ||
feff2f05 | 6130 | -- If the expression is the value of an object that is known to be |
6131 | -- valid, then clearly the expression value itself is valid. | |
ee6ba406 | 6132 | |
6133 | elsif Is_Entity_Name (Expr) | |
6134 | and then Is_Known_Valid (Entity (Expr)) | |
985fe5d6 | 6135 | |
6136 | -- Exclude volatile variables | |
6137 | ||
6138 | and then not Treat_As_Volatile (Entity (Expr)) | |
ee6ba406 | 6139 | then |
6140 | return True; | |
6141 | ||
0577b0b1 | 6142 | -- References to discriminants are always considered valid. The value |
6143 | -- of a discriminant gets checked when the object is built. Within the | |
6144 | -- record, we consider it valid, and it is important to do so, since | |
6145 | -- otherwise we can try to generate bogus validity checks which | |
feff2f05 | 6146 | -- reference discriminants out of scope. Discriminants of concurrent |
6147 | -- types are excluded for the same reason. | |
0577b0b1 | 6148 | |
6149 | elsif Is_Entity_Name (Expr) | |
feff2f05 | 6150 | and then Denotes_Discriminant (Expr, Check_Concurrent => True) |
0577b0b1 | 6151 | then |
6152 | return True; | |
6153 | ||
feff2f05 | 6154 | -- If the type is one for which all values are known valid, then we are |
6155 | -- sure that the value is valid except in the slightly odd case where | |
6156 | -- the expression is a reference to a variable whose size has been | |
6157 | -- explicitly set to a value greater than the object size. | |
ee6ba406 | 6158 | |
6159 | elsif Is_Known_Valid (Typ) then | |
6160 | if Is_Entity_Name (Expr) | |
6161 | and then Ekind (Entity (Expr)) = E_Variable | |
6162 | and then Esize (Entity (Expr)) > Esize (Typ) | |
6163 | then | |
6164 | return False; | |
6165 | else | |
6166 | return True; | |
6167 | end if; | |
6168 | ||
6169 | -- Integer and character literals always have valid values, where | |
6170 | -- appropriate these will be range checked in any case. | |
6171 | ||
20cf157b | 6172 | elsif Nkind_In (Expr, N_Integer_Literal, N_Character_Literal) then |
ee6ba406 | 6173 | return True; |
91e47010 | 6174 | |
ee6ba406 | 6175 | -- If we have a type conversion or a qualification of a known valid |
6176 | -- value, then the result will always be valid. | |
6177 | ||
20cf157b | 6178 | elsif Nkind_In (Expr, N_Type_Conversion, N_Qualified_Expression) then |
ee6ba406 | 6179 | return Expr_Known_Valid (Expression (Expr)); |
6180 | ||
1eb1395f | 6181 | -- Case of expression is a non-floating-point operator. In this case we |
6182 | -- can assume the result is valid the generated code for the operator | |
6183 | -- will include whatever checks are needed (e.g. range checks) to ensure | |
6184 | -- validity. This assumption does not hold for the floating-point case, | |
6185 | -- since floating-point operators can generate Infinite or NaN results | |
6186 | -- which are considered invalid. | |
6187 | ||
6188 | -- Historical note: in older versions, the exemption of floating-point | |
6189 | -- types from this assumption was done only in cases where the parent | |
6190 | -- was an assignment, function call or parameter association. Presumably | |
6191 | -- the idea was that in other contexts, the result would be checked | |
6192 | -- elsewhere, but this list of cases was missing tests (at least the | |
6193 | -- N_Object_Declaration case, as shown by a reported missing validity | |
6194 | -- check), and it is not clear why function calls but not procedure | |
6195 | -- calls were tested for. It really seems more accurate and much | |
6196 | -- safer to recognize that expressions which are the result of a | |
6197 | -- floating-point operator can never be assumed to be valid. | |
6198 | ||
6199 | elsif Nkind (Expr) in N_Op and then not Is_Floating_Point_Type (Typ) then | |
6200 | return True; | |
1d90d657 | 6201 | |
feff2f05 | 6202 | -- The result of a membership test is always valid, since it is true or |
6203 | -- false, there are no other possibilities. | |
0577b0b1 | 6204 | |
6205 | elsif Nkind (Expr) in N_Membership_Test then | |
6206 | return True; | |
6207 | ||
ee6ba406 | 6208 | -- For all other cases, we do not know the expression is valid |
6209 | ||
6210 | else | |
6211 | return False; | |
6212 | end if; | |
6213 | end Expr_Known_Valid; | |
6214 | ||
9dfe12ae | 6215 | ---------------- |
6216 | -- Find_Check -- | |
6217 | ---------------- | |
6218 | ||
6219 | procedure Find_Check | |
6220 | (Expr : Node_Id; | |
6221 | Check_Type : Character; | |
6222 | Target_Type : Entity_Id; | |
6223 | Entry_OK : out Boolean; | |
6224 | Check_Num : out Nat; | |
6225 | Ent : out Entity_Id; | |
6226 | Ofs : out Uint) | |
6227 | is | |
6228 | function Within_Range_Of | |
6229 | (Target_Type : Entity_Id; | |
314a23b6 | 6230 | Check_Type : Entity_Id) return Boolean; |
9dfe12ae | 6231 | -- Given a requirement for checking a range against Target_Type, and |
6232 | -- and a range Check_Type against which a check has already been made, | |
6233 | -- determines if the check against check type is sufficient to ensure | |
6234 | -- that no check against Target_Type is required. | |
6235 | ||
6236 | --------------------- | |
6237 | -- Within_Range_Of -- | |
6238 | --------------------- | |
6239 | ||
6240 | function Within_Range_Of | |
6241 | (Target_Type : Entity_Id; | |
314a23b6 | 6242 | Check_Type : Entity_Id) return Boolean |
9dfe12ae | 6243 | is |
6244 | begin | |
6245 | if Target_Type = Check_Type then | |
6246 | return True; | |
6247 | ||
6248 | else | |
6249 | declare | |
6250 | Tlo : constant Node_Id := Type_Low_Bound (Target_Type); | |
6251 | Thi : constant Node_Id := Type_High_Bound (Target_Type); | |
6252 | Clo : constant Node_Id := Type_Low_Bound (Check_Type); | |
6253 | Chi : constant Node_Id := Type_High_Bound (Check_Type); | |
6254 | ||
6255 | begin | |
6256 | if (Tlo = Clo | |
6257 | or else (Compile_Time_Known_Value (Tlo) | |
6258 | and then | |
6259 | Compile_Time_Known_Value (Clo) | |
6260 | and then | |
6261 | Expr_Value (Clo) >= Expr_Value (Tlo))) | |
6262 | and then | |
6263 | (Thi = Chi | |
6264 | or else (Compile_Time_Known_Value (Thi) | |
6265 | and then | |
6266 | Compile_Time_Known_Value (Chi) | |
6267 | and then | |
6268 | Expr_Value (Chi) <= Expr_Value (Clo))) | |
6269 | then | |
6270 | return True; | |
6271 | else | |
6272 | return False; | |
6273 | end if; | |
6274 | end; | |
6275 | end if; | |
6276 | end Within_Range_Of; | |
6277 | ||
6278 | -- Start of processing for Find_Check | |
6279 | ||
6280 | begin | |
ed195555 | 6281 | -- Establish default, in case no entry is found |
9dfe12ae | 6282 | |
6283 | Check_Num := 0; | |
6284 | ||
6285 | -- Case of expression is simple entity reference | |
6286 | ||
6287 | if Is_Entity_Name (Expr) then | |
6288 | Ent := Entity (Expr); | |
6289 | Ofs := Uint_0; | |
6290 | ||
6291 | -- Case of expression is entity + known constant | |
6292 | ||
6293 | elsif Nkind (Expr) = N_Op_Add | |
6294 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
6295 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
6296 | then | |
6297 | Ent := Entity (Left_Opnd (Expr)); | |
6298 | Ofs := Expr_Value (Right_Opnd (Expr)); | |
6299 | ||
6300 | -- Case of expression is entity - known constant | |
6301 | ||
6302 | elsif Nkind (Expr) = N_Op_Subtract | |
6303 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
6304 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
6305 | then | |
6306 | Ent := Entity (Left_Opnd (Expr)); | |
6307 | Ofs := UI_Negate (Expr_Value (Right_Opnd (Expr))); | |
6308 | ||
6309 | -- Any other expression is not of the right form | |
6310 | ||
6311 | else | |
6312 | Ent := Empty; | |
6313 | Ofs := Uint_0; | |
6314 | Entry_OK := False; | |
6315 | return; | |
6316 | end if; | |
6317 | ||
feff2f05 | 6318 | -- Come here with expression of appropriate form, check if entity is an |
6319 | -- appropriate one for our purposes. | |
9dfe12ae | 6320 | |
6321 | if (Ekind (Ent) = E_Variable | |
cc60bd16 | 6322 | or else Is_Constant_Object (Ent)) |
9dfe12ae | 6323 | and then not Is_Library_Level_Entity (Ent) |
6324 | then | |
6325 | Entry_OK := True; | |
6326 | else | |
6327 | Entry_OK := False; | |
6328 | return; | |
6329 | end if; | |
6330 | ||
6331 | -- See if there is matching check already | |
6332 | ||
6333 | for J in reverse 1 .. Num_Saved_Checks loop | |
6334 | declare | |
6335 | SC : Saved_Check renames Saved_Checks (J); | |
9dfe12ae | 6336 | begin |
6337 | if SC.Killed = False | |
6338 | and then SC.Entity = Ent | |
6339 | and then SC.Offset = Ofs | |
6340 | and then SC.Check_Type = Check_Type | |
6341 | and then Within_Range_Of (Target_Type, SC.Target_Type) | |
6342 | then | |
6343 | Check_Num := J; | |
6344 | return; | |
6345 | end if; | |
6346 | end; | |
6347 | end loop; | |
6348 | ||
6349 | -- If we fall through entry was not found | |
6350 | ||
9dfe12ae | 6351 | return; |
6352 | end Find_Check; | |
6353 | ||
6354 | --------------------------------- | |
6355 | -- Generate_Discriminant_Check -- | |
6356 | --------------------------------- | |
6357 | ||
6358 | -- Note: the code for this procedure is derived from the | |
feff2f05 | 6359 | -- Emit_Discriminant_Check Routine in trans.c. |
9dfe12ae | 6360 | |
6361 | procedure Generate_Discriminant_Check (N : Node_Id) is | |
6362 | Loc : constant Source_Ptr := Sloc (N); | |
6363 | Pref : constant Node_Id := Prefix (N); | |
6364 | Sel : constant Node_Id := Selector_Name (N); | |
6365 | ||
6366 | Orig_Comp : constant Entity_Id := | |
b6341c67 | 6367 | Original_Record_Component (Entity (Sel)); |
9dfe12ae | 6368 | -- The original component to be checked |
6369 | ||
6370 | Discr_Fct : constant Entity_Id := | |
b6341c67 | 6371 | Discriminant_Checking_Func (Orig_Comp); |
9dfe12ae | 6372 | -- The discriminant checking function |
6373 | ||
6374 | Discr : Entity_Id; | |
6375 | -- One discriminant to be checked in the type | |
6376 | ||
6377 | Real_Discr : Entity_Id; | |
6378 | -- Actual discriminant in the call | |
6379 | ||
6380 | Pref_Type : Entity_Id; | |
6381 | -- Type of relevant prefix (ignoring private/access stuff) | |
6382 | ||
6383 | Args : List_Id; | |
6384 | -- List of arguments for function call | |
6385 | ||
6386 | Formal : Entity_Id; | |
feff2f05 | 6387 | -- Keep track of the formal corresponding to the actual we build for |
6388 | -- each discriminant, in order to be able to perform the necessary type | |
6389 | -- conversions. | |
9dfe12ae | 6390 | |
6391 | Scomp : Node_Id; | |
6392 | -- Selected component reference for checking function argument | |
6393 | ||
6394 | begin | |
6395 | Pref_Type := Etype (Pref); | |
6396 | ||
6397 | -- Force evaluation of the prefix, so that it does not get evaluated | |
6398 | -- twice (once for the check, once for the actual reference). Such a | |
20cf157b | 6399 | -- double evaluation is always a potential source of inefficiency, and |
6400 | -- is functionally incorrect in the volatile case, or when the prefix | |
f9906591 | 6401 | -- may have side effects. A nonvolatile entity or a component of a |
6402 | -- nonvolatile entity requires no evaluation. | |
9dfe12ae | 6403 | |
6404 | if Is_Entity_Name (Pref) then | |
6405 | if Treat_As_Volatile (Entity (Pref)) then | |
6406 | Force_Evaluation (Pref, Name_Req => True); | |
6407 | end if; | |
6408 | ||
6409 | elsif Treat_As_Volatile (Etype (Pref)) then | |
20cf157b | 6410 | Force_Evaluation (Pref, Name_Req => True); |
9dfe12ae | 6411 | |
6412 | elsif Nkind (Pref) = N_Selected_Component | |
6413 | and then Is_Entity_Name (Prefix (Pref)) | |
6414 | then | |
6415 | null; | |
6416 | ||
6417 | else | |
6418 | Force_Evaluation (Pref, Name_Req => True); | |
6419 | end if; | |
6420 | ||
6421 | -- For a tagged type, use the scope of the original component to | |
6422 | -- obtain the type, because ??? | |
6423 | ||
6424 | if Is_Tagged_Type (Scope (Orig_Comp)) then | |
6425 | Pref_Type := Scope (Orig_Comp); | |
6426 | ||
feff2f05 | 6427 | -- For an untagged derived type, use the discriminants of the parent |
6428 | -- which have been renamed in the derivation, possibly by a one-to-many | |
d1a2e31b | 6429 | -- discriminant constraint. For untagged type, initially get the Etype |
feff2f05 | 6430 | -- of the prefix |
9dfe12ae | 6431 | |
6432 | else | |
6433 | if Is_Derived_Type (Pref_Type) | |
6434 | and then Number_Discriminants (Pref_Type) /= | |
6435 | Number_Discriminants (Etype (Base_Type (Pref_Type))) | |
6436 | then | |
6437 | Pref_Type := Etype (Base_Type (Pref_Type)); | |
6438 | end if; | |
6439 | end if; | |
6440 | ||
6441 | -- We definitely should have a checking function, This routine should | |
6442 | -- not be called if no discriminant checking function is present. | |
6443 | ||
6444 | pragma Assert (Present (Discr_Fct)); | |
6445 | ||
6446 | -- Create the list of the actual parameters for the call. This list | |
6447 | -- is the list of the discriminant fields of the record expression to | |
6448 | -- be discriminant checked. | |
6449 | ||
6450 | Args := New_List; | |
6451 | Formal := First_Formal (Discr_Fct); | |
6452 | Discr := First_Discriminant (Pref_Type); | |
6453 | while Present (Discr) loop | |
6454 | ||
6455 | -- If we have a corresponding discriminant field, and a parent | |
6456 | -- subtype is present, then we want to use the corresponding | |
6457 | -- discriminant since this is the one with the useful value. | |
6458 | ||
6459 | if Present (Corresponding_Discriminant (Discr)) | |
6460 | and then Ekind (Pref_Type) = E_Record_Type | |
6461 | and then Present (Parent_Subtype (Pref_Type)) | |
6462 | then | |
6463 | Real_Discr := Corresponding_Discriminant (Discr); | |
6464 | else | |
6465 | Real_Discr := Discr; | |
6466 | end if; | |
6467 | ||
6468 | -- Construct the reference to the discriminant | |
6469 | ||
6470 | Scomp := | |
6471 | Make_Selected_Component (Loc, | |
6472 | Prefix => | |
6473 | Unchecked_Convert_To (Pref_Type, | |
6474 | Duplicate_Subexpr (Pref)), | |
6475 | Selector_Name => New_Occurrence_Of (Real_Discr, Loc)); | |
6476 | ||
6477 | -- Manually analyze and resolve this selected component. We really | |
6478 | -- want it just as it appears above, and do not want the expander | |
feff2f05 | 6479 | -- playing discriminal games etc with this reference. Then we append |
6480 | -- the argument to the list we are gathering. | |
9dfe12ae | 6481 | |
6482 | Set_Etype (Scomp, Etype (Real_Discr)); | |
6483 | Set_Analyzed (Scomp, True); | |
6484 | Append_To (Args, Convert_To (Etype (Formal), Scomp)); | |
6485 | ||
6486 | Next_Formal_With_Extras (Formal); | |
6487 | Next_Discriminant (Discr); | |
6488 | end loop; | |
6489 | ||
6490 | -- Now build and insert the call | |
6491 | ||
6492 | Insert_Action (N, | |
6493 | Make_Raise_Constraint_Error (Loc, | |
6494 | Condition => | |
6495 | Make_Function_Call (Loc, | |
20cf157b | 6496 | Name => New_Occurrence_Of (Discr_Fct, Loc), |
9dfe12ae | 6497 | Parameter_Associations => Args), |
6498 | Reason => CE_Discriminant_Check_Failed)); | |
6499 | end Generate_Discriminant_Check; | |
6500 | ||
5c99c290 | 6501 | --------------------------- |
6502 | -- Generate_Index_Checks -- | |
6503 | --------------------------- | |
9dfe12ae | 6504 | |
6505 | procedure Generate_Index_Checks (N : Node_Id) is | |
05f3e139 | 6506 | |
6507 | function Entity_Of_Prefix return Entity_Id; | |
6508 | -- Returns the entity of the prefix of N (or Empty if not found) | |
6509 | ||
3f42e2a7 | 6510 | ---------------------- |
6511 | -- Entity_Of_Prefix -- | |
6512 | ---------------------- | |
6513 | ||
05f3e139 | 6514 | function Entity_Of_Prefix return Entity_Id is |
e5d38095 | 6515 | P : Node_Id; |
6516 | ||
05f3e139 | 6517 | begin |
e5d38095 | 6518 | P := Prefix (N); |
05f3e139 | 6519 | while not Is_Entity_Name (P) loop |
6520 | if not Nkind_In (P, N_Selected_Component, | |
6521 | N_Indexed_Component) | |
6522 | then | |
6523 | return Empty; | |
6524 | end if; | |
6525 | ||
6526 | P := Prefix (P); | |
6527 | end loop; | |
6528 | ||
6529 | return Entity (P); | |
6530 | end Entity_Of_Prefix; | |
6531 | ||
6532 | -- Local variables | |
6533 | ||
6534 | Loc : constant Source_Ptr := Sloc (N); | |
6535 | A : constant Node_Id := Prefix (N); | |
6536 | A_Ent : constant Entity_Id := Entity_Of_Prefix; | |
6537 | Sub : Node_Id; | |
9dfe12ae | 6538 | |
3f42e2a7 | 6539 | -- Start of processing for Generate_Index_Checks |
6540 | ||
9dfe12ae | 6541 | begin |
05f3e139 | 6542 | -- Ignore call if the prefix is not an array since we have a serious |
6543 | -- error in the sources. Ignore it also if index checks are suppressed | |
6544 | -- for array object or type. | |
0577b0b1 | 6545 | |
05f3e139 | 6546 | if not Is_Array_Type (Etype (A)) |
20cf157b | 6547 | or else (Present (A_Ent) and then Index_Checks_Suppressed (A_Ent)) |
0577b0b1 | 6548 | or else Index_Checks_Suppressed (Etype (A)) |
6549 | then | |
6550 | return; | |
df9fba45 | 6551 | |
6552 | -- The indexed component we are dealing with contains 'Loop_Entry in its | |
6553 | -- prefix. This case arises when analysis has determined that constructs | |
6554 | -- such as | |
6555 | ||
6556 | -- Prefix'Loop_Entry (Expr) | |
6557 | -- Prefix'Loop_Entry (Expr1, Expr2, ... ExprN) | |
6558 | ||
6559 | -- require rewriting for error detection purposes. A side effect of this | |
6560 | -- action is the generation of index checks that mention 'Loop_Entry. | |
6561 | -- Delay the generation of the check until 'Loop_Entry has been properly | |
6562 | -- expanded. This is done in Expand_Loop_Entry_Attributes. | |
6563 | ||
6564 | elsif Nkind (Prefix (N)) = N_Attribute_Reference | |
6565 | and then Attribute_Name (Prefix (N)) = Name_Loop_Entry | |
6566 | then | |
6567 | return; | |
0577b0b1 | 6568 | end if; |
6569 | ||
05f3e139 | 6570 | -- Generate a raise of constraint error with the appropriate reason and |
6571 | -- a condition of the form: | |
6572 | ||
3f42e2a7 | 6573 | -- Base_Type (Sub) not in Array'Range (Subscript) |
05f3e139 | 6574 | |
6575 | -- Note that the reason we generate the conversion to the base type here | |
6576 | -- is that we definitely want the range check to take place, even if it | |
6577 | -- looks like the subtype is OK. Optimization considerations that allow | |
6578 | -- us to omit the check have already been taken into account in the | |
6579 | -- setting of the Do_Range_Check flag earlier on. | |
0577b0b1 | 6580 | |
9dfe12ae | 6581 | Sub := First (Expressions (N)); |
05f3e139 | 6582 | |
6583 | -- Handle string literals | |
6584 | ||
6585 | if Ekind (Etype (A)) = E_String_Literal_Subtype then | |
9dfe12ae | 6586 | if Do_Range_Check (Sub) then |
6587 | Set_Do_Range_Check (Sub, False); | |
6588 | ||
05f3e139 | 6589 | -- For string literals we obtain the bounds of the string from the |
6590 | -- associated subtype. | |
9dfe12ae | 6591 | |
05f3e139 | 6592 | Insert_Action (N, |
094ed68e | 6593 | Make_Raise_Constraint_Error (Loc, |
6594 | Condition => | |
6595 | Make_Not_In (Loc, | |
6596 | Left_Opnd => | |
6597 | Convert_To (Base_Type (Etype (Sub)), | |
6598 | Duplicate_Subexpr_Move_Checks (Sub)), | |
6599 | Right_Opnd => | |
6600 | Make_Attribute_Reference (Loc, | |
83c6c069 | 6601 | Prefix => New_Occurrence_Of (Etype (A), Loc), |
094ed68e | 6602 | Attribute_Name => Name_Range)), |
6603 | Reason => CE_Index_Check_Failed)); | |
05f3e139 | 6604 | end if; |
9dfe12ae | 6605 | |
05f3e139 | 6606 | -- General case |
9dfe12ae | 6607 | |
05f3e139 | 6608 | else |
6609 | declare | |
6610 | A_Idx : Node_Id := Empty; | |
6611 | A_Range : Node_Id; | |
6612 | Ind : Nat; | |
6613 | Num : List_Id; | |
6614 | Range_N : Node_Id; | |
9dfe12ae | 6615 | |
05f3e139 | 6616 | begin |
6617 | A_Idx := First_Index (Etype (A)); | |
6618 | Ind := 1; | |
6619 | while Present (Sub) loop | |
6620 | if Do_Range_Check (Sub) then | |
6621 | Set_Do_Range_Check (Sub, False); | |
9dfe12ae | 6622 | |
05f3e139 | 6623 | -- Force evaluation except for the case of a simple name of |
f9906591 | 6624 | -- a nonvolatile entity. |
9dfe12ae | 6625 | |
05f3e139 | 6626 | if not Is_Entity_Name (Sub) |
6627 | or else Treat_As_Volatile (Entity (Sub)) | |
6628 | then | |
6629 | Force_Evaluation (Sub); | |
6630 | end if; | |
9dfe12ae | 6631 | |
05f3e139 | 6632 | if Nkind (A_Idx) = N_Range then |
6633 | A_Range := A_Idx; | |
6634 | ||
6635 | elsif Nkind (A_Idx) = N_Identifier | |
6636 | or else Nkind (A_Idx) = N_Expanded_Name | |
6637 | then | |
6638 | A_Range := Scalar_Range (Entity (A_Idx)); | |
6639 | ||
6640 | else pragma Assert (Nkind (A_Idx) = N_Subtype_Indication); | |
6641 | A_Range := Range_Expression (Constraint (A_Idx)); | |
6642 | end if; | |
6643 | ||
6644 | -- For array objects with constant bounds we can generate | |
6645 | -- the index check using the bounds of the type of the index | |
6646 | ||
6647 | if Present (A_Ent) | |
6648 | and then Ekind (A_Ent) = E_Variable | |
6649 | and then Is_Constant_Bound (Low_Bound (A_Range)) | |
6650 | and then Is_Constant_Bound (High_Bound (A_Range)) | |
6651 | then | |
6652 | Range_N := | |
6653 | Make_Attribute_Reference (Loc, | |
3f42e2a7 | 6654 | Prefix => |
83c6c069 | 6655 | New_Occurrence_Of (Etype (A_Idx), Loc), |
05f3e139 | 6656 | Attribute_Name => Name_Range); |
6657 | ||
6658 | -- For arrays with non-constant bounds we cannot generate | |
6659 | -- the index check using the bounds of the type of the index | |
6660 | -- since it may reference discriminants of some enclosing | |
6661 | -- type. We obtain the bounds directly from the prefix | |
6662 | -- object. | |
6663 | ||
6664 | else | |
6665 | if Ind = 1 then | |
6666 | Num := No_List; | |
6667 | else | |
6668 | Num := New_List (Make_Integer_Literal (Loc, Ind)); | |
6669 | end if; | |
6670 | ||
6671 | Range_N := | |
6672 | Make_Attribute_Reference (Loc, | |
6673 | Prefix => | |
6674 | Duplicate_Subexpr_Move_Checks (A, Name_Req => True), | |
6675 | Attribute_Name => Name_Range, | |
6676 | Expressions => Num); | |
6677 | end if; | |
6678 | ||
6679 | Insert_Action (N, | |
094ed68e | 6680 | Make_Raise_Constraint_Error (Loc, |
6681 | Condition => | |
6682 | Make_Not_In (Loc, | |
6683 | Left_Opnd => | |
6684 | Convert_To (Base_Type (Etype (Sub)), | |
6685 | Duplicate_Subexpr_Move_Checks (Sub)), | |
6686 | Right_Opnd => Range_N), | |
6687 | Reason => CE_Index_Check_Failed)); | |
05f3e139 | 6688 | end if; |
6689 | ||
6690 | A_Idx := Next_Index (A_Idx); | |
6691 | Ind := Ind + 1; | |
6692 | Next (Sub); | |
6693 | end loop; | |
6694 | end; | |
6695 | end if; | |
9dfe12ae | 6696 | end Generate_Index_Checks; |
6697 | ||
6698 | -------------------------- | |
6699 | -- Generate_Range_Check -- | |
6700 | -------------------------- | |
6701 | ||
6702 | procedure Generate_Range_Check | |
6703 | (N : Node_Id; | |
6704 | Target_Type : Entity_Id; | |
6705 | Reason : RT_Exception_Code) | |
6706 | is | |
6707 | Loc : constant Source_Ptr := Sloc (N); | |
6708 | Source_Type : constant Entity_Id := Etype (N); | |
6709 | Source_Base_Type : constant Entity_Id := Base_Type (Source_Type); | |
6710 | Target_Base_Type : constant Entity_Id := Base_Type (Target_Type); | |
6711 | ||
1f5d83cf | 6712 | procedure Convert_And_Check_Range; |
6713 | -- Convert the conversion operand to the target base type and save in | |
6714 | -- a temporary. Then check the converted value against the range of the | |
6715 | -- target subtype. | |
6716 | ||
124f1911 | 6717 | ----------------------------- |
6718 | -- Convert_And_Check_Range -- | |
6719 | ----------------------------- | |
1f5d83cf | 6720 | |
124f1911 | 6721 | procedure Convert_And_Check_Range is |
1f5d83cf | 6722 | Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
6723 | ||
124f1911 | 6724 | begin |
6725 | -- We make a temporary to hold the value of the converted value | |
6726 | -- (converted to the base type), and then do the test against this | |
6727 | -- temporary. The conversion itself is replaced by an occurrence of | |
6728 | -- Tnn and followed by the explicit range check. Note that checks | |
6729 | -- are suppressed for this code, since we don't want a recursive | |
1f5d83cf | 6730 | -- range check popping up. |
6731 | ||
124f1911 | 6732 | -- Tnn : constant Target_Base_Type := Target_Base_Type (N); |
6733 | -- [constraint_error when Tnn not in Target_Type] | |
6734 | ||
1f5d83cf | 6735 | Insert_Actions (N, New_List ( |
6736 | Make_Object_Declaration (Loc, | |
6737 | Defining_Identifier => Tnn, | |
6738 | Object_Definition => New_Occurrence_Of (Target_Base_Type, Loc), | |
6739 | Constant_Present => True, | |
6740 | Expression => | |
6741 | Make_Type_Conversion (Loc, | |
6742 | Subtype_Mark => New_Occurrence_Of (Target_Base_Type, Loc), | |
6743 | Expression => Duplicate_Subexpr (N))), | |
6744 | ||
6745 | Make_Raise_Constraint_Error (Loc, | |
6746 | Condition => | |
6747 | Make_Not_In (Loc, | |
6748 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
6749 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
6750 | Reason => Reason)), | |
6751 | Suppress => All_Checks); | |
6752 | ||
6753 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
6754 | ||
6755 | -- Set the type of N, because the declaration for Tnn might not | |
6756 | -- be analyzed yet, as is the case if N appears within a record | |
6757 | -- declaration, as a discriminant constraint or expression. | |
6758 | ||
6759 | Set_Etype (N, Target_Base_Type); | |
6760 | end Convert_And_Check_Range; | |
6761 | ||
6762 | -- Start of processing for Generate_Range_Check | |
6763 | ||
9dfe12ae | 6764 | begin |
feff2f05 | 6765 | -- First special case, if the source type is already within the range |
6766 | -- of the target type, then no check is needed (probably we should have | |
6767 | -- stopped Do_Range_Check from being set in the first place, but better | |
cda40848 | 6768 | -- late than never in preventing junk code and junk flag settings. |
9dfe12ae | 6769 | |
7a1dabb3 | 6770 | if In_Subrange_Of (Source_Type, Target_Type) |
b40670e1 | 6771 | |
6772 | -- We do NOT apply this if the source node is a literal, since in this | |
6773 | -- case the literal has already been labeled as having the subtype of | |
6774 | -- the target. | |
6775 | ||
9dfe12ae | 6776 | and then not |
b40670e1 | 6777 | (Nkind_In (N, N_Integer_Literal, N_Real_Literal, N_Character_Literal) |
9dfe12ae | 6778 | or else |
b40670e1 | 6779 | (Is_Entity_Name (N) |
6780 | and then Ekind (Entity (N)) = E_Enumeration_Literal)) | |
9dfe12ae | 6781 | then |
cda40848 | 6782 | Set_Do_Range_Check (N, False); |
9dfe12ae | 6783 | return; |
6784 | end if; | |
6785 | ||
cda40848 | 6786 | -- Here a check is needed. If the expander is not active, or if we are |
6787 | -- in GNATProve mode, then simply set the Do_Range_Check flag and we | |
6788 | -- are done. In both these cases, we just want to see the range check | |
6789 | -- flag set, we do not want to generate the explicit range check code. | |
6790 | ||
6791 | if GNATprove_Mode or else not Expander_Active then | |
6792 | Set_Do_Range_Check (N, True); | |
6793 | return; | |
6794 | end if; | |
6795 | ||
6796 | -- Here we will generate an explicit range check, so we don't want to | |
6797 | -- set the Do_Range check flag, since the range check is taken care of | |
6798 | -- by the code we will generate. | |
6799 | ||
6800 | Set_Do_Range_Check (N, False); | |
6801 | ||
6802 | -- Force evaluation of the node, so that it does not get evaluated twice | |
6803 | -- (once for the check, once for the actual reference). Such a double | |
6804 | -- evaluation is always a potential source of inefficiency, and is | |
6805 | -- functionally incorrect in the volatile case. | |
9dfe12ae | 6806 | |
b40670e1 | 6807 | if not Is_Entity_Name (N) or else Treat_As_Volatile (Entity (N)) then |
9dfe12ae | 6808 | Force_Evaluation (N); |
6809 | end if; | |
6810 | ||
feff2f05 | 6811 | -- The easiest case is when Source_Base_Type and Target_Base_Type are |
6812 | -- the same since in this case we can simply do a direct check of the | |
6813 | -- value of N against the bounds of Target_Type. | |
9dfe12ae | 6814 | |
6815 | -- [constraint_error when N not in Target_Type] | |
6816 | ||
6817 | -- Note: this is by far the most common case, for example all cases of | |
6818 | -- checks on the RHS of assignments are in this category, but not all | |
6819 | -- cases are like this. Notably conversions can involve two types. | |
6820 | ||
6821 | if Source_Base_Type = Target_Base_Type then | |
99ed4b4c | 6822 | |
6823 | -- Insert the explicit range check. Note that we suppress checks for | |
6824 | -- this code, since we don't want a recursive range check popping up. | |
6825 | ||
9dfe12ae | 6826 | Insert_Action (N, |
6827 | Make_Raise_Constraint_Error (Loc, | |
6828 | Condition => | |
6829 | Make_Not_In (Loc, | |
6830 | Left_Opnd => Duplicate_Subexpr (N), | |
6831 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
99ed4b4c | 6832 | Reason => Reason), |
6833 | Suppress => All_Checks); | |
9dfe12ae | 6834 | |
6835 | -- Next test for the case where the target type is within the bounds | |
6836 | -- of the base type of the source type, since in this case we can | |
6837 | -- simply convert these bounds to the base type of T to do the test. | |
6838 | ||
6839 | -- [constraint_error when N not in | |
6840 | -- Source_Base_Type (Target_Type'First) | |
6841 | -- .. | |
6842 | -- Source_Base_Type(Target_Type'Last))] | |
6843 | ||
f2a06be9 | 6844 | -- The conversions will always work and need no check |
9dfe12ae | 6845 | |
a9b57347 | 6846 | -- Unchecked_Convert_To is used instead of Convert_To to handle the case |
6847 | -- of converting from an enumeration value to an integer type, such as | |
6848 | -- occurs for the case of generating a range check on Enum'Val(Exp) | |
6849 | -- (which used to be handled by gigi). This is OK, since the conversion | |
6850 | -- itself does not require a check. | |
6851 | ||
7a1dabb3 | 6852 | elsif In_Subrange_Of (Target_Type, Source_Base_Type) then |
99ed4b4c | 6853 | |
6854 | -- Insert the explicit range check. Note that we suppress checks for | |
6855 | -- this code, since we don't want a recursive range check popping up. | |
6856 | ||
1f5d83cf | 6857 | if Is_Discrete_Type (Source_Base_Type) |
6858 | and then | |
6859 | Is_Discrete_Type (Target_Base_Type) | |
6860 | then | |
6861 | Insert_Action (N, | |
6862 | Make_Raise_Constraint_Error (Loc, | |
6863 | Condition => | |
6864 | Make_Not_In (Loc, | |
6865 | Left_Opnd => Duplicate_Subexpr (N), | |
6866 | ||
6867 | Right_Opnd => | |
6868 | Make_Range (Loc, | |
6869 | Low_Bound => | |
6870 | Unchecked_Convert_To (Source_Base_Type, | |
6871 | Make_Attribute_Reference (Loc, | |
6872 | Prefix => | |
6873 | New_Occurrence_Of (Target_Type, Loc), | |
6874 | Attribute_Name => Name_First)), | |
6875 | ||
6876 | High_Bound => | |
6877 | Unchecked_Convert_To (Source_Base_Type, | |
6878 | Make_Attribute_Reference (Loc, | |
6879 | Prefix => | |
6880 | New_Occurrence_Of (Target_Type, Loc), | |
6881 | Attribute_Name => Name_Last)))), | |
6882 | Reason => Reason), | |
6883 | Suppress => All_Checks); | |
9dfe12ae | 6884 | |
1f5d83cf | 6885 | -- For conversions involving at least one type that is not discrete, |
6886 | -- first convert to target type and then generate the range check. | |
6887 | -- This avoids problems with values that are close to a bound of the | |
6888 | -- target type that would fail a range check when done in a larger | |
6889 | -- source type before converting but would pass if converted with | |
6890 | -- rounding and then checked (such as in float-to-float conversions). | |
6891 | ||
6892 | else | |
6893 | Convert_And_Check_Range; | |
6894 | end if; | |
9dfe12ae | 6895 | |
feff2f05 | 6896 | -- Note that at this stage we now that the Target_Base_Type is not in |
6897 | -- the range of the Source_Base_Type (since even the Target_Type itself | |
6898 | -- is not in this range). It could still be the case that Source_Type is | |
6899 | -- in range of the target base type since we have not checked that case. | |
9dfe12ae | 6900 | |
feff2f05 | 6901 | -- If that is the case, we can freely convert the source to the target, |
6902 | -- and then test the target result against the bounds. | |
9dfe12ae | 6903 | |
7a1dabb3 | 6904 | elsif In_Subrange_Of (Source_Type, Target_Base_Type) then |
1f5d83cf | 6905 | Convert_And_Check_Range; |
9dfe12ae | 6906 | |
6907 | -- At this stage, we know that we have two scalar types, which are | |
6908 | -- directly convertible, and where neither scalar type has a base | |
6909 | -- range that is in the range of the other scalar type. | |
6910 | ||
6911 | -- The only way this can happen is with a signed and unsigned type. | |
6912 | -- So test for these two cases: | |
6913 | ||
6914 | else | |
6915 | -- Case of the source is unsigned and the target is signed | |
6916 | ||
6917 | if Is_Unsigned_Type (Source_Base_Type) | |
6918 | and then not Is_Unsigned_Type (Target_Base_Type) | |
6919 | then | |
6920 | -- If the source is unsigned and the target is signed, then we | |
6921 | -- know that the source is not shorter than the target (otherwise | |
6922 | -- the source base type would be in the target base type range). | |
6923 | ||
feff2f05 | 6924 | -- In other words, the unsigned type is either the same size as |
6925 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 6926 | |
6927 | pragma Assert | |
6928 | (Esize (Source_Base_Type) >= Esize (Target_Base_Type)); | |
6929 | ||
6930 | -- We only need to check the low bound if the low bound of the | |
6931 | -- target type is non-negative. If the low bound of the target | |
6932 | -- type is negative, then we know that we will fit fine. | |
6933 | ||
6934 | -- If the high bound of the target type is negative, then we | |
6935 | -- know we have a constraint error, since we can't possibly | |
6936 | -- have a negative source. | |
6937 | ||
6938 | -- With these two checks out of the way, we can do the check | |
6939 | -- using the source type safely | |
6940 | ||
39a0c1d3 | 6941 | -- This is definitely the most annoying case. |
9dfe12ae | 6942 | |
6943 | -- [constraint_error | |
6944 | -- when (Target_Type'First >= 0 | |
6945 | -- and then | |
6946 | -- N < Source_Base_Type (Target_Type'First)) | |
6947 | -- or else Target_Type'Last < 0 | |
6948 | -- or else N > Source_Base_Type (Target_Type'Last)]; | |
6949 | ||
6950 | -- We turn off all checks since we know that the conversions | |
6951 | -- will work fine, given the guards for negative values. | |
6952 | ||
6953 | Insert_Action (N, | |
6954 | Make_Raise_Constraint_Error (Loc, | |
6955 | Condition => | |
6956 | Make_Or_Else (Loc, | |
6957 | Make_Or_Else (Loc, | |
6958 | Left_Opnd => | |
6959 | Make_And_Then (Loc, | |
6960 | Left_Opnd => Make_Op_Ge (Loc, | |
6961 | Left_Opnd => | |
6962 | Make_Attribute_Reference (Loc, | |
6963 | Prefix => | |
6964 | New_Occurrence_Of (Target_Type, Loc), | |
6965 | Attribute_Name => Name_First), | |
6966 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
6967 | ||
6968 | Right_Opnd => | |
6969 | Make_Op_Lt (Loc, | |
6970 | Left_Opnd => Duplicate_Subexpr (N), | |
6971 | Right_Opnd => | |
6972 | Convert_To (Source_Base_Type, | |
6973 | Make_Attribute_Reference (Loc, | |
6974 | Prefix => | |
6975 | New_Occurrence_Of (Target_Type, Loc), | |
6976 | Attribute_Name => Name_First)))), | |
6977 | ||
6978 | Right_Opnd => | |
6979 | Make_Op_Lt (Loc, | |
6980 | Left_Opnd => | |
6981 | Make_Attribute_Reference (Loc, | |
6982 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
6983 | Attribute_Name => Name_Last), | |
6984 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0))), | |
6985 | ||
6986 | Right_Opnd => | |
6987 | Make_Op_Gt (Loc, | |
6988 | Left_Opnd => Duplicate_Subexpr (N), | |
6989 | Right_Opnd => | |
6990 | Convert_To (Source_Base_Type, | |
6991 | Make_Attribute_Reference (Loc, | |
6992 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
6993 | Attribute_Name => Name_Last)))), | |
6994 | ||
6995 | Reason => Reason), | |
6996 | Suppress => All_Checks); | |
6997 | ||
6998 | -- Only remaining possibility is that the source is signed and | |
fc75802a | 6999 | -- the target is unsigned. |
9dfe12ae | 7000 | |
7001 | else | |
7002 | pragma Assert (not Is_Unsigned_Type (Source_Base_Type) | |
20cf157b | 7003 | and then Is_Unsigned_Type (Target_Base_Type)); |
9dfe12ae | 7004 | |
feff2f05 | 7005 | -- If the source is signed and the target is unsigned, then we |
7006 | -- know that the target is not shorter than the source (otherwise | |
7007 | -- the target base type would be in the source base type range). | |
9dfe12ae | 7008 | |
feff2f05 | 7009 | -- In other words, the unsigned type is either the same size as |
7010 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 7011 | |
feff2f05 | 7012 | -- Clearly we have an error if the source value is negative since |
7013 | -- no unsigned type can have negative values. If the source type | |
7014 | -- is non-negative, then the check can be done using the target | |
7015 | -- type. | |
9dfe12ae | 7016 | |
7017 | -- Tnn : constant Target_Base_Type (N) := Target_Type; | |
7018 | ||
7019 | -- [constraint_error | |
7020 | -- when N < 0 or else Tnn not in Target_Type]; | |
7021 | ||
feff2f05 | 7022 | -- We turn off all checks for the conversion of N to the target |
7023 | -- base type, since we generate the explicit check to ensure that | |
7024 | -- the value is non-negative | |
9dfe12ae | 7025 | |
7026 | declare | |
46eb6933 | 7027 | Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
9dfe12ae | 7028 | |
7029 | begin | |
7030 | Insert_Actions (N, New_List ( | |
7031 | Make_Object_Declaration (Loc, | |
7032 | Defining_Identifier => Tnn, | |
7033 | Object_Definition => | |
7034 | New_Occurrence_Of (Target_Base_Type, Loc), | |
7035 | Constant_Present => True, | |
7036 | Expression => | |
a9b57347 | 7037 | Make_Unchecked_Type_Conversion (Loc, |
9dfe12ae | 7038 | Subtype_Mark => |
7039 | New_Occurrence_Of (Target_Base_Type, Loc), | |
7040 | Expression => Duplicate_Subexpr (N))), | |
7041 | ||
7042 | Make_Raise_Constraint_Error (Loc, | |
7043 | Condition => | |
7044 | Make_Or_Else (Loc, | |
7045 | Left_Opnd => | |
7046 | Make_Op_Lt (Loc, | |
7047 | Left_Opnd => Duplicate_Subexpr (N), | |
7048 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
7049 | ||
7050 | Right_Opnd => | |
7051 | Make_Not_In (Loc, | |
7052 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
7053 | Right_Opnd => | |
7054 | New_Occurrence_Of (Target_Type, Loc))), | |
7055 | ||
20cf157b | 7056 | Reason => Reason)), |
9dfe12ae | 7057 | Suppress => All_Checks); |
7058 | ||
feff2f05 | 7059 | -- Set the Etype explicitly, because Insert_Actions may have |
7060 | -- placed the declaration in the freeze list for an enclosing | |
7061 | -- construct, and thus it is not analyzed yet. | |
9dfe12ae | 7062 | |
7063 | Set_Etype (Tnn, Target_Base_Type); | |
7064 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
7065 | end; | |
7066 | end if; | |
7067 | end if; | |
7068 | end Generate_Range_Check; | |
7069 | ||
2af58f67 | 7070 | ------------------ |
7071 | -- Get_Check_Id -- | |
7072 | ------------------ | |
7073 | ||
7074 | function Get_Check_Id (N : Name_Id) return Check_Id is | |
7075 | begin | |
7076 | -- For standard check name, we can do a direct computation | |
7077 | ||
7078 | if N in First_Check_Name .. Last_Check_Name then | |
7079 | return Check_Id (N - (First_Check_Name - 1)); | |
7080 | ||
7081 | -- For non-standard names added by pragma Check_Name, search table | |
7082 | ||
7083 | else | |
7084 | for J in All_Checks + 1 .. Check_Names.Last loop | |
7085 | if Check_Names.Table (J) = N then | |
7086 | return J; | |
7087 | end if; | |
7088 | end loop; | |
7089 | end if; | |
7090 | ||
7091 | -- No matching name found | |
7092 | ||
7093 | return No_Check_Id; | |
7094 | end Get_Check_Id; | |
7095 | ||
ee6ba406 | 7096 | --------------------- |
7097 | -- Get_Discriminal -- | |
7098 | --------------------- | |
7099 | ||
7100 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is | |
7101 | Loc : constant Source_Ptr := Sloc (E); | |
7102 | D : Entity_Id; | |
7103 | Sc : Entity_Id; | |
7104 | ||
7105 | begin | |
0577b0b1 | 7106 | -- The bound can be a bona fide parameter of a protected operation, |
7107 | -- rather than a prival encoded as an in-parameter. | |
7108 | ||
7109 | if No (Discriminal_Link (Entity (Bound))) then | |
7110 | return Bound; | |
7111 | end if; | |
7112 | ||
2af58f67 | 7113 | -- Climb the scope stack looking for an enclosing protected type. If |
7114 | -- we run out of scopes, return the bound itself. | |
7115 | ||
7116 | Sc := Scope (E); | |
7117 | while Present (Sc) loop | |
7118 | if Sc = Standard_Standard then | |
7119 | return Bound; | |
2af58f67 | 7120 | elsif Ekind (Sc) = E_Protected_Type then |
7121 | exit; | |
7122 | end if; | |
7123 | ||
7124 | Sc := Scope (Sc); | |
7125 | end loop; | |
7126 | ||
ee6ba406 | 7127 | D := First_Discriminant (Sc); |
2af58f67 | 7128 | while Present (D) loop |
7129 | if Chars (D) = Chars (Bound) then | |
7130 | return New_Occurrence_Of (Discriminal (D), Loc); | |
7131 | end if; | |
ee6ba406 | 7132 | |
ee6ba406 | 7133 | Next_Discriminant (D); |
7134 | end loop; | |
7135 | ||
2af58f67 | 7136 | return Bound; |
ee6ba406 | 7137 | end Get_Discriminal; |
7138 | ||
2af58f67 | 7139 | ---------------------- |
7140 | -- Get_Range_Checks -- | |
7141 | ---------------------- | |
7142 | ||
7143 | function Get_Range_Checks | |
7144 | (Ck_Node : Node_Id; | |
7145 | Target_Typ : Entity_Id; | |
7146 | Source_Typ : Entity_Id := Empty; | |
7147 | Warn_Node : Node_Id := Empty) return Check_Result | |
7148 | is | |
7149 | begin | |
20cf157b | 7150 | return |
7151 | Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Warn_Node); | |
2af58f67 | 7152 | end Get_Range_Checks; |
7153 | ||
ee6ba406 | 7154 | ------------------ |
7155 | -- Guard_Access -- | |
7156 | ------------------ | |
7157 | ||
7158 | function Guard_Access | |
7159 | (Cond : Node_Id; | |
7160 | Loc : Source_Ptr; | |
314a23b6 | 7161 | Ck_Node : Node_Id) return Node_Id |
ee6ba406 | 7162 | is |
7163 | begin | |
7164 | if Nkind (Cond) = N_Or_Else then | |
7165 | Set_Paren_Count (Cond, 1); | |
7166 | end if; | |
7167 | ||
7168 | if Nkind (Ck_Node) = N_Allocator then | |
7169 | return Cond; | |
20cf157b | 7170 | |
ee6ba406 | 7171 | else |
7172 | return | |
7173 | Make_And_Then (Loc, | |
7174 | Left_Opnd => | |
7175 | Make_Op_Ne (Loc, | |
9dfe12ae | 7176 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), |
ee6ba406 | 7177 | Right_Opnd => Make_Null (Loc)), |
7178 | Right_Opnd => Cond); | |
7179 | end if; | |
7180 | end Guard_Access; | |
7181 | ||
7182 | ----------------------------- | |
7183 | -- Index_Checks_Suppressed -- | |
7184 | ----------------------------- | |
7185 | ||
7186 | function Index_Checks_Suppressed (E : Entity_Id) return Boolean is | |
7187 | begin | |
9dfe12ae | 7188 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
7189 | return Is_Check_Suppressed (E, Index_Check); | |
7190 | else | |
fafc6b97 | 7191 | return Scope_Suppress.Suppress (Index_Check); |
9dfe12ae | 7192 | end if; |
ee6ba406 | 7193 | end Index_Checks_Suppressed; |
7194 | ||
7195 | ---------------- | |
7196 | -- Initialize -- | |
7197 | ---------------- | |
7198 | ||
7199 | procedure Initialize is | |
7200 | begin | |
7201 | for J in Determine_Range_Cache_N'Range loop | |
7202 | Determine_Range_Cache_N (J) := Empty; | |
7203 | end loop; | |
2af58f67 | 7204 | |
7205 | Check_Names.Init; | |
7206 | ||
7207 | for J in Int range 1 .. All_Checks loop | |
7208 | Check_Names.Append (Name_Id (Int (First_Check_Name) + J - 1)); | |
7209 | end loop; | |
ee6ba406 | 7210 | end Initialize; |
7211 | ||
7212 | ------------------------- | |
7213 | -- Insert_Range_Checks -- | |
7214 | ------------------------- | |
7215 | ||
7216 | procedure Insert_Range_Checks | |
7217 | (Checks : Check_Result; | |
7218 | Node : Node_Id; | |
7219 | Suppress_Typ : Entity_Id; | |
7220 | Static_Sloc : Source_Ptr := No_Location; | |
7221 | Flag_Node : Node_Id := Empty; | |
7222 | Do_Before : Boolean := False) | |
7223 | is | |
2b4f2458 | 7224 | Checks_On : constant Boolean := |
7225 | not Index_Checks_Suppressed (Suppress_Typ) | |
7226 | or else | |
7227 | not Range_Checks_Suppressed (Suppress_Typ); | |
7228 | ||
7229 | Check_Node : Node_Id; | |
ee6ba406 | 7230 | Internal_Flag_Node : Node_Id := Flag_Node; |
7231 | Internal_Static_Sloc : Source_Ptr := Static_Sloc; | |
7232 | ||
ee6ba406 | 7233 | begin |
feff2f05 | 7234 | -- For now we just return if Checks_On is false, however this should be |
7235 | -- enhanced to check for an always True value in the condition and to | |
7236 | -- generate a compilation warning??? | |
ee6ba406 | 7237 | |
ac9184ed | 7238 | if not Expander_Active or not Checks_On then |
ee6ba406 | 7239 | return; |
7240 | end if; | |
7241 | ||
7242 | if Static_Sloc = No_Location then | |
7243 | Internal_Static_Sloc := Sloc (Node); | |
7244 | end if; | |
7245 | ||
7246 | if No (Flag_Node) then | |
7247 | Internal_Flag_Node := Node; | |
7248 | end if; | |
7249 | ||
7250 | for J in 1 .. 2 loop | |
7251 | exit when No (Checks (J)); | |
7252 | ||
7253 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
7254 | and then Present (Condition (Checks (J))) | |
7255 | then | |
7256 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
7257 | Check_Node := Checks (J); | |
7258 | Mark_Rewrite_Insertion (Check_Node); | |
7259 | ||
7260 | if Do_Before then | |
7261 | Insert_Before_And_Analyze (Node, Check_Node); | |
7262 | else | |
7263 | Insert_After_And_Analyze (Node, Check_Node); | |
7264 | end if; | |
7265 | ||
7266 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
7267 | end if; | |
7268 | ||
7269 | else | |
7270 | Check_Node := | |
f15731c4 | 7271 | Make_Raise_Constraint_Error (Internal_Static_Sloc, |
7272 | Reason => CE_Range_Check_Failed); | |
ee6ba406 | 7273 | Mark_Rewrite_Insertion (Check_Node); |
7274 | ||
7275 | if Do_Before then | |
7276 | Insert_Before_And_Analyze (Node, Check_Node); | |
7277 | else | |
7278 | Insert_After_And_Analyze (Node, Check_Node); | |
7279 | end if; | |
7280 | end if; | |
7281 | end loop; | |
7282 | end Insert_Range_Checks; | |
7283 | ||
7284 | ------------------------ | |
7285 | -- Insert_Valid_Check -- | |
7286 | ------------------------ | |
7287 | ||
aaec8d13 | 7288 | procedure Insert_Valid_Check |
7289 | (Expr : Node_Id; | |
7290 | Related_Id : Entity_Id := Empty; | |
7291 | Is_Low_Bound : Boolean := False; | |
7292 | Is_High_Bound : Boolean := False) | |
7293 | is | |
ee6ba406 | 7294 | Loc : constant Source_Ptr := Sloc (Expr); |
70580828 | 7295 | Typ : constant Entity_Id := Etype (Expr); |
8b718dab | 7296 | Exp : Node_Id; |
ee6ba406 | 7297 | |
7298 | begin | |
aaec8d13 | 7299 | -- Do not insert if checks off, or if not checking validity or if |
7300 | -- expression is known to be valid. | |
ee6ba406 | 7301 | |
0577b0b1 | 7302 | if not Validity_Checks_On |
7303 | or else Range_Or_Validity_Checks_Suppressed (Expr) | |
06ad5813 | 7304 | or else Expr_Known_Valid (Expr) |
ee6ba406 | 7305 | then |
8b718dab | 7306 | return; |
ee6ba406 | 7307 | |
42c57d55 | 7308 | -- Do not insert checks within a predicate function. This will arise |
7309 | -- if the current unit and the predicate function are being compiled | |
7310 | -- with validity checks enabled. | |
70580828 | 7311 | |
89e864b9 | 7312 | elsif Present (Predicate_Function (Typ)) |
70580828 | 7313 | and then Current_Scope = Predicate_Function (Typ) |
7314 | then | |
7315 | return; | |
70580828 | 7316 | |
310c1cde | 7317 | -- If the expression is a packed component of a modular type of the |
7318 | -- right size, the data is always valid. | |
7319 | ||
89e864b9 | 7320 | elsif Nkind (Expr) = N_Selected_Component |
310c1cde | 7321 | and then Present (Component_Clause (Entity (Selector_Name (Expr)))) |
7322 | and then Is_Modular_Integer_Type (Typ) | |
7323 | and then Modulus (Typ) = 2 ** Esize (Entity (Selector_Name (Expr))) | |
7324 | then | |
7325 | return; | |
89e864b9 | 7326 | |
7327 | -- Do not generate a validity check when inside a generic unit as this | |
7328 | -- is an expansion activity. | |
7329 | ||
7330 | elsif Inside_A_Generic then | |
7331 | return; | |
310c1cde | 7332 | end if; |
7333 | ||
8b718dab | 7334 | -- If we have a checked conversion, then validity check applies to |
7335 | -- the expression inside the conversion, not the result, since if | |
7336 | -- the expression inside is valid, then so is the conversion result. | |
ee6ba406 | 7337 | |
8b718dab | 7338 | Exp := Expr; |
7339 | while Nkind (Exp) = N_Type_Conversion loop | |
7340 | Exp := Expression (Exp); | |
7341 | end loop; | |
7342 | ||
fdb8488b | 7343 | -- Do not generate a check for a variable which already validates the |
7344 | -- value of an assignable object. | |
7345 | ||
7346 | if Is_Validation_Variable_Reference (Exp) then | |
7347 | return; | |
7348 | end if; | |
7349 | ||
0577b0b1 | 7350 | declare |
49adf385 | 7351 | CE : Node_Id; |
49adf385 | 7352 | PV : Node_Id; |
7353 | Var_Id : Entity_Id; | |
05fcfafb | 7354 | |
0577b0b1 | 7355 | begin |
fdb8488b | 7356 | -- If the expression denotes an assignable object, capture its value |
7357 | -- in a variable and replace the original expression by the variable. | |
7358 | -- This approach has several effects: | |
06ad5813 | 7359 | |
fdb8488b | 7360 | -- 1) The evaluation of the object results in only one read in the |
7361 | -- case where the object is atomic or volatile. | |
fa771c05 | 7362 | |
49adf385 | 7363 | -- Var ... := Object; -- read |
fa771c05 | 7364 | |
fdb8488b | 7365 | -- 2) The captured value is the one verified by attribute 'Valid. |
7366 | -- As a result the object is not evaluated again, which would | |
7367 | -- result in an unwanted read in the case where the object is | |
7368 | -- atomic or volatile. | |
7369 | ||
49adf385 | 7370 | -- if not Var'Valid then -- OK, no read of Object |
fdb8488b | 7371 | |
7372 | -- if not Object'Valid then -- Wrong, extra read of Object | |
7373 | ||
7374 | -- 3) The captured value replaces the original object reference. | |
7375 | -- As a result the object is not evaluated again, in the same | |
7376 | -- vein as 2). | |
7377 | ||
49adf385 | 7378 | -- ... Var ... -- OK, no read of Object |
fdb8488b | 7379 | |
7380 | -- ... Object ... -- Wrong, extra read of Object | |
06ad5813 | 7381 | |
fdb8488b | 7382 | -- 4) The use of a variable to capture the value of the object |
7383 | -- allows the propagation of any changes back to the original | |
7384 | -- object. | |
7385 | ||
7386 | -- procedure Call (Val : in out ...); | |
7387 | ||
49adf385 | 7388 | -- Var : ... := Object; -- read Object |
7389 | -- if not Var'Valid then -- validity check | |
7390 | -- Call (Var); -- modify Var | |
7391 | -- Object := Var; -- update Object | |
fdb8488b | 7392 | |
7393 | if Is_Variable (Exp) then | |
49adf385 | 7394 | Var_Id := Make_Temporary (Loc, 'T', Exp); |
fdb8488b | 7395 | |
7396 | Insert_Action (Exp, | |
7397 | Make_Object_Declaration (Loc, | |
49adf385 | 7398 | Defining_Identifier => Var_Id, |
fdb8488b | 7399 | Object_Definition => New_Occurrence_Of (Typ, Loc), |
bf5f89dc | 7400 | Expression => New_Copy_Tree (Exp)), |
7401 | Suppress => Validity_Check); | |
7402 | ||
7403 | Set_Validated_Object (Var_Id, New_Copy_Tree (Exp)); | |
fdb8488b | 7404 | |
49adf385 | 7405 | Rewrite (Exp, New_Occurrence_Of (Var_Id, Loc)); |
7406 | PV := New_Occurrence_Of (Var_Id, Loc); | |
fdb8488b | 7407 | |
7408 | -- Otherwise the expression does not denote a variable. Force its | |
7409 | -- evaluation by capturing its value in a constant. Generate: | |
7410 | ||
7411 | -- Temp : constant ... := Exp; | |
7412 | ||
7413 | else | |
7414 | Force_Evaluation | |
7415 | (Exp => Exp, | |
7416 | Related_Id => Related_Id, | |
7417 | Is_Low_Bound => Is_Low_Bound, | |
7418 | Is_High_Bound => Is_High_Bound); | |
7419 | ||
7420 | PV := New_Copy_Tree (Exp); | |
7421 | end if; | |
0577b0b1 | 7422 | |
443bdccb | 7423 | -- A rather specialized test. If PV is an analyzed expression which |
7424 | -- is an indexed component of a packed array that has not been | |
7425 | -- properly expanded, turn off its Analyzed flag to make sure it | |
5f46de53 | 7426 | -- gets properly reexpanded. If the prefix is an access value, |
7427 | -- the dereference will be added later. | |
23abd64d | 7428 | |
7429 | -- The reason this arises is that Duplicate_Subexpr_No_Checks did | |
7430 | -- an analyze with the old parent pointer. This may point e.g. to | |
7431 | -- a subprogram call, which deactivates this expansion. | |
7432 | ||
7433 | if Analyzed (PV) | |
7434 | and then Nkind (PV) = N_Indexed_Component | |
5f46de53 | 7435 | and then Is_Array_Type (Etype (Prefix (PV))) |
a88a5773 | 7436 | and then Present (Packed_Array_Impl_Type (Etype (Prefix (PV)))) |
23abd64d | 7437 | then |
7438 | Set_Analyzed (PV, False); | |
7439 | end if; | |
7440 | ||
fa771c05 | 7441 | -- Build the raise CE node to check for validity. We build a type |
7442 | -- qualification for the prefix, since it may not be of the form of | |
7443 | -- a name, and we don't care in this context! | |
23abd64d | 7444 | |
7445 | CE := | |
aaec8d13 | 7446 | Make_Raise_Constraint_Error (Loc, |
7447 | Condition => | |
7448 | Make_Op_Not (Loc, | |
7449 | Right_Opnd => | |
7450 | Make_Attribute_Reference (Loc, | |
7451 | Prefix => PV, | |
7452 | Attribute_Name => Name_Valid)), | |
7453 | Reason => CE_Invalid_Data); | |
23abd64d | 7454 | |
7455 | -- Insert the validity check. Note that we do this with validity | |
7456 | -- checks turned off, to avoid recursion, we do not want validity | |
39a0c1d3 | 7457 | -- checks on the validity checking code itself. |
23abd64d | 7458 | |
7459 | Insert_Action (Expr, CE, Suppress => Validity_Check); | |
0577b0b1 | 7460 | |
6fb3c314 | 7461 | -- If the expression is a reference to an element of a bit-packed |
0577b0b1 | 7462 | -- array, then it is rewritten as a renaming declaration. If the |
7463 | -- expression is an actual in a call, it has not been expanded, | |
7464 | -- waiting for the proper point at which to do it. The same happens | |
7465 | -- with renamings, so that we have to force the expansion now. This | |
7466 | -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb | |
7467 | -- and exp_ch6.adb. | |
7468 | ||
7469 | if Is_Entity_Name (Exp) | |
7470 | and then Nkind (Parent (Entity (Exp))) = | |
20cf157b | 7471 | N_Object_Renaming_Declaration |
0577b0b1 | 7472 | then |
7473 | declare | |
7474 | Old_Exp : constant Node_Id := Name (Parent (Entity (Exp))); | |
7475 | begin | |
7476 | if Nkind (Old_Exp) = N_Indexed_Component | |
7477 | and then Is_Bit_Packed_Array (Etype (Prefix (Old_Exp))) | |
7478 | then | |
7479 | Expand_Packed_Element_Reference (Old_Exp); | |
7480 | end if; | |
7481 | end; | |
7482 | end if; | |
0577b0b1 | 7483 | end; |
ee6ba406 | 7484 | end Insert_Valid_Check; |
7485 | ||
3cce7f32 | 7486 | ------------------------------------- |
7487 | -- Is_Signed_Integer_Arithmetic_Op -- | |
7488 | ------------------------------------- | |
7489 | ||
7490 | function Is_Signed_Integer_Arithmetic_Op (N : Node_Id) return Boolean is | |
7491 | begin | |
7492 | case Nkind (N) is | |
99378362 | 7493 | when N_Op_Abs |
7494 | | N_Op_Add | |
7495 | | N_Op_Divide | |
7496 | | N_Op_Expon | |
7497 | | N_Op_Minus | |
7498 | | N_Op_Mod | |
7499 | | N_Op_Multiply | |
7500 | | N_Op_Plus | |
7501 | | N_Op_Rem | |
7502 | | N_Op_Subtract | |
7503 | => | |
3cce7f32 | 7504 | return Is_Signed_Integer_Type (Etype (N)); |
7505 | ||
99378362 | 7506 | when N_Case_Expression |
7507 | | N_If_Expression | |
7508 | => | |
0326b4d4 | 7509 | return Is_Signed_Integer_Type (Etype (N)); |
7510 | ||
3cce7f32 | 7511 | when others => |
7512 | return False; | |
7513 | end case; | |
7514 | end Is_Signed_Integer_Arithmetic_Op; | |
7515 | ||
fa7497e8 | 7516 | ---------------------------------- |
7517 | -- Install_Null_Excluding_Check -- | |
7518 | ---------------------------------- | |
7519 | ||
7520 | procedure Install_Null_Excluding_Check (N : Node_Id) is | |
9f294c82 | 7521 | Loc : constant Source_Ptr := Sloc (Parent (N)); |
84d0d4a5 | 7522 | Typ : constant Entity_Id := Etype (N); |
7523 | ||
7b31b357 | 7524 | function Safe_To_Capture_In_Parameter_Value return Boolean; |
7525 | -- Determines if it is safe to capture Known_Non_Null status for an | |
7526 | -- the entity referenced by node N. The caller ensures that N is indeed | |
7527 | -- an entity name. It is safe to capture the non-null status for an IN | |
7528 | -- parameter when the reference occurs within a declaration that is sure | |
7529 | -- to be executed as part of the declarative region. | |
7870823d | 7530 | |
84d0d4a5 | 7531 | procedure Mark_Non_Null; |
7870823d | 7532 | -- After installation of check, if the node in question is an entity |
7533 | -- name, then mark this entity as non-null if possible. | |
7534 | ||
7b31b357 | 7535 | function Safe_To_Capture_In_Parameter_Value return Boolean is |
7870823d | 7536 | E : constant Entity_Id := Entity (N); |
7537 | S : constant Entity_Id := Current_Scope; | |
7538 | S_Par : Node_Id; | |
7539 | ||
7540 | begin | |
7b31b357 | 7541 | if Ekind (E) /= E_In_Parameter then |
7542 | return False; | |
7543 | end if; | |
7870823d | 7544 | |
7545 | -- Two initial context checks. We must be inside a subprogram body | |
7546 | -- with declarations and reference must not appear in nested scopes. | |
7547 | ||
7b31b357 | 7548 | if (Ekind (S) /= E_Function and then Ekind (S) /= E_Procedure) |
7870823d | 7549 | or else Scope (E) /= S |
7550 | then | |
7551 | return False; | |
7552 | end if; | |
7553 | ||
7554 | S_Par := Parent (Parent (S)); | |
7555 | ||
7556 | if Nkind (S_Par) /= N_Subprogram_Body | |
7557 | or else No (Declarations (S_Par)) | |
7558 | then | |
7559 | return False; | |
7560 | end if; | |
7561 | ||
7562 | declare | |
7563 | N_Decl : Node_Id; | |
7564 | P : Node_Id; | |
7565 | ||
7566 | begin | |
7567 | -- Retrieve the declaration node of N (if any). Note that N | |
7568 | -- may be a part of a complex initialization expression. | |
7569 | ||
7570 | P := Parent (N); | |
7571 | N_Decl := Empty; | |
7572 | while Present (P) loop | |
7573 | ||
7b31b357 | 7574 | -- If we have a short circuit form, and we are within the right |
7575 | -- hand expression, we return false, since the right hand side | |
7576 | -- is not guaranteed to be elaborated. | |
7577 | ||
7578 | if Nkind (P) in N_Short_Circuit | |
7579 | and then N = Right_Opnd (P) | |
7580 | then | |
7581 | return False; | |
7582 | end if; | |
7583 | ||
92f1631f | 7584 | -- Similarly, if we are in an if expression and not part of the |
7585 | -- condition, then we return False, since neither the THEN or | |
7586 | -- ELSE dependent expressions will always be elaborated. | |
7b31b357 | 7587 | |
92f1631f | 7588 | if Nkind (P) = N_If_Expression |
7b31b357 | 7589 | and then N /= First (Expressions (P)) |
7590 | then | |
7591 | return False; | |
e977c0cf | 7592 | end if; |
7593 | ||
20cf157b | 7594 | -- If within a case expression, and not part of the expression, |
7595 | -- then return False, since a particular dependent expression | |
7596 | -- may not always be elaborated | |
e977c0cf | 7597 | |
7598 | if Nkind (P) = N_Case_Expression | |
7599 | and then N /= Expression (P) | |
7600 | then | |
7601 | return False; | |
7b31b357 | 7602 | end if; |
7603 | ||
20cf157b | 7604 | -- While traversing the parent chain, if node N belongs to a |
7605 | -- statement, then it may never appear in a declarative region. | |
7870823d | 7606 | |
7607 | if Nkind (P) in N_Statement_Other_Than_Procedure_Call | |
7608 | or else Nkind (P) = N_Procedure_Call_Statement | |
7609 | then | |
7610 | return False; | |
7611 | end if; | |
7612 | ||
7b31b357 | 7613 | -- If we are at a declaration, record it and exit |
7614 | ||
7870823d | 7615 | if Nkind (P) in N_Declaration |
7616 | and then Nkind (P) not in N_Subprogram_Specification | |
7617 | then | |
7618 | N_Decl := P; | |
7619 | exit; | |
7620 | end if; | |
7621 | ||
7622 | P := Parent (P); | |
7623 | end loop; | |
7624 | ||
7625 | if No (N_Decl) then | |
7626 | return False; | |
7627 | end if; | |
7628 | ||
7629 | return List_Containing (N_Decl) = Declarations (S_Par); | |
7630 | end; | |
7b31b357 | 7631 | end Safe_To_Capture_In_Parameter_Value; |
84d0d4a5 | 7632 | |
7633 | ------------------- | |
7634 | -- Mark_Non_Null -- | |
7635 | ------------------- | |
7636 | ||
7637 | procedure Mark_Non_Null is | |
7638 | begin | |
7870823d | 7639 | -- Only case of interest is if node N is an entity name |
7640 | ||
84d0d4a5 | 7641 | if Is_Entity_Name (N) then |
7870823d | 7642 | |
7643 | -- For sure, we want to clear an indication that this is known to | |
39a0c1d3 | 7644 | -- be null, since if we get past this check, it definitely is not. |
7870823d | 7645 | |
84d0d4a5 | 7646 | Set_Is_Known_Null (Entity (N), False); |
7647 | ||
7870823d | 7648 | -- We can mark the entity as known to be non-null if either it is |
7649 | -- safe to capture the value, or in the case of an IN parameter, | |
7650 | -- which is a constant, if the check we just installed is in the | |
7651 | -- declarative region of the subprogram body. In this latter case, | |
7b31b357 | 7652 | -- a check is decisive for the rest of the body if the expression |
7653 | -- is sure to be elaborated, since we know we have to elaborate | |
7654 | -- all declarations before executing the body. | |
7655 | ||
7656 | -- Couldn't this always be part of Safe_To_Capture_Value ??? | |
7870823d | 7657 | |
7658 | if Safe_To_Capture_Value (N, Entity (N)) | |
7b31b357 | 7659 | or else Safe_To_Capture_In_Parameter_Value |
7870823d | 7660 | then |
7661 | Set_Is_Known_Non_Null (Entity (N)); | |
84d0d4a5 | 7662 | end if; |
7663 | end if; | |
7664 | end Mark_Non_Null; | |
7665 | ||
7666 | -- Start of processing for Install_Null_Excluding_Check | |
fa7497e8 | 7667 | |
7668 | begin | |
84d0d4a5 | 7669 | pragma Assert (Is_Access_Type (Typ)); |
fa7497e8 | 7670 | |
46e32b5e | 7671 | -- No check inside a generic, check will be emitted in instance |
fa7497e8 | 7672 | |
84d0d4a5 | 7673 | if Inside_A_Generic then |
fa7497e8 | 7674 | return; |
84d0d4a5 | 7675 | end if; |
7676 | ||
7677 | -- No check needed if known to be non-null | |
7678 | ||
7679 | if Known_Non_Null (N) then | |
05fcfafb | 7680 | return; |
84d0d4a5 | 7681 | end if; |
fa7497e8 | 7682 | |
84d0d4a5 | 7683 | -- If known to be null, here is where we generate a compile time check |
7684 | ||
7685 | if Known_Null (N) then | |
d16989f1 | 7686 | |
20cf157b | 7687 | -- Avoid generating warning message inside init procs. In SPARK mode |
7688 | -- we can go ahead and call Apply_Compile_Time_Constraint_Error | |
46e32b5e | 7689 | -- since it will be turned into an error in any case. |
d16989f1 | 7690 | |
46e32b5e | 7691 | if (not Inside_Init_Proc or else SPARK_Mode = On) |
7692 | ||
28d5d68f | 7693 | -- Do not emit the warning within a conditional expression, |
7694 | -- where the expression might not be evaluated, and the warning | |
7695 | -- appear as extraneous noise. | |
46e32b5e | 7696 | |
7697 | and then not Within_Case_Or_If_Expression (N) | |
7698 | then | |
d16989f1 | 7699 | Apply_Compile_Time_Constraint_Error |
4098232e | 7700 | (N, "null value not allowed here??", CE_Access_Check_Failed); |
46e32b5e | 7701 | |
7702 | -- Remaining cases, where we silently insert the raise | |
7703 | ||
d16989f1 | 7704 | else |
7705 | Insert_Action (N, | |
7706 | Make_Raise_Constraint_Error (Loc, | |
7707 | Reason => CE_Access_Check_Failed)); | |
7708 | end if; | |
7709 | ||
84d0d4a5 | 7710 | Mark_Non_Null; |
7711 | return; | |
7712 | end if; | |
7713 | ||
7714 | -- If entity is never assigned, for sure a warning is appropriate | |
7715 | ||
7716 | if Is_Entity_Name (N) then | |
7717 | Check_Unset_Reference (N); | |
fa7497e8 | 7718 | end if; |
84d0d4a5 | 7719 | |
7720 | -- No check needed if checks are suppressed on the range. Note that we | |
7721 | -- don't set Is_Known_Non_Null in this case (we could legitimately do | |
7722 | -- so, since the program is erroneous, but we don't like to casually | |
7723 | -- propagate such conclusions from erroneosity). | |
7724 | ||
7725 | if Access_Checks_Suppressed (Typ) then | |
7726 | return; | |
7727 | end if; | |
7728 | ||
2af58f67 | 7729 | -- No check needed for access to concurrent record types generated by |
7730 | -- the expander. This is not just an optimization (though it does indeed | |
7731 | -- remove junk checks). It also avoids generation of junk warnings. | |
7732 | ||
7733 | if Nkind (N) in N_Has_Chars | |
7734 | and then Chars (N) = Name_uObject | |
7735 | and then Is_Concurrent_Record_Type | |
7736 | (Directly_Designated_Type (Etype (N))) | |
7737 | then | |
7738 | return; | |
7739 | end if; | |
7740 | ||
228836e8 | 7741 | -- No check needed in interface thunks since the runtime check is |
7742 | -- already performed at the caller side. | |
7743 | ||
7744 | if Is_Thunk (Current_Scope) then | |
7745 | return; | |
7746 | end if; | |
7747 | ||
472ea160 | 7748 | -- No check needed for the Get_Current_Excep.all.all idiom generated by |
7749 | -- the expander within exception handlers, since we know that the value | |
7750 | -- can never be null. | |
7751 | ||
7752 | -- Is this really the right way to do this? Normally we generate such | |
7753 | -- code in the expander with checks off, and that's how we suppress this | |
7754 | -- kind of junk check ??? | |
7755 | ||
7756 | if Nkind (N) = N_Function_Call | |
7757 | and then Nkind (Name (N)) = N_Explicit_Dereference | |
7758 | and then Nkind (Prefix (Name (N))) = N_Identifier | |
7759 | and then Is_RTE (Entity (Prefix (Name (N))), RE_Get_Current_Excep) | |
7760 | then | |
7761 | return; | |
7762 | end if; | |
7763 | ||
84d0d4a5 | 7764 | -- Otherwise install access check |
7765 | ||
7766 | Insert_Action (N, | |
7767 | Make_Raise_Constraint_Error (Loc, | |
7768 | Condition => | |
7769 | Make_Op_Eq (Loc, | |
7770 | Left_Opnd => Duplicate_Subexpr_Move_Checks (N), | |
7771 | Right_Opnd => Make_Null (Loc)), | |
7772 | Reason => CE_Access_Check_Failed)); | |
7773 | ||
7774 | Mark_Non_Null; | |
fa7497e8 | 7775 | end Install_Null_Excluding_Check; |
7776 | ||
7e933b61 | 7777 | ----------------------------------------- |
7778 | -- Install_Primitive_Elaboration_Check -- | |
7779 | ----------------------------------------- | |
7780 | ||
7781 | procedure Install_Primitive_Elaboration_Check (Subp_Body : Node_Id) is | |
7e933b61 | 7782 | function Within_Compilation_Unit_Instance |
7783 | (Subp_Id : Entity_Id) return Boolean; | |
7784 | -- Determine whether subprogram Subp_Id appears within an instance which | |
7785 | -- acts as a compilation unit. | |
7786 | ||
7787 | -------------------------------------- | |
7788 | -- Within_Compilation_Unit_Instance -- | |
7789 | -------------------------------------- | |
7790 | ||
7791 | function Within_Compilation_Unit_Instance | |
7792 | (Subp_Id : Entity_Id) return Boolean | |
7793 | is | |
7794 | Pack : Entity_Id; | |
7795 | ||
7796 | begin | |
7797 | -- Examine the scope chain looking for a compilation-unit-level | |
7798 | -- instance. | |
7799 | ||
7800 | Pack := Scope (Subp_Id); | |
7801 | while Present (Pack) and then Pack /= Standard_Standard loop | |
7802 | if Ekind (Pack) = E_Package | |
7803 | and then Is_Generic_Instance (Pack) | |
7804 | and then Nkind (Parent (Unit_Declaration_Node (Pack))) = | |
7805 | N_Compilation_Unit | |
7806 | then | |
7807 | return True; | |
7808 | end if; | |
7809 | ||
7810 | Pack := Scope (Pack); | |
7811 | end loop; | |
7812 | ||
7813 | return False; | |
7814 | end Within_Compilation_Unit_Instance; | |
7815 | ||
7816 | -- Local declarations | |
7817 | ||
7818 | Context : constant Node_Id := Parent (Subp_Body); | |
7819 | Loc : constant Source_Ptr := Sloc (Subp_Body); | |
7820 | Subp_Id : constant Entity_Id := Unique_Defining_Entity (Subp_Body); | |
7821 | Subp_Decl : constant Node_Id := Unit_Declaration_Node (Subp_Id); | |
7822 | ||
7823 | Decls : List_Id; | |
7824 | Flag_Id : Entity_Id; | |
7825 | Set_Ins : Node_Id; | |
7826 | Tag_Typ : Entity_Id; | |
7827 | ||
7828 | -- Start of processing for Install_Primitive_Elaboration_Check | |
7829 | ||
7830 | begin | |
7831 | -- Do not generate an elaboration check in compilation modes where | |
7832 | -- expansion is not desirable. | |
7833 | ||
7834 | if ASIS_Mode or GNATprove_Mode then | |
7835 | return; | |
7836 | ||
f0e731f2 | 7837 | -- Do not generate an elaboration check if all checks have been |
7838 | -- suppressed. | |
62c62e4b | 7839 | |
f0e731f2 | 7840 | elsif Suppress_Checks then |
62c62e4b | 7841 | return; |
7842 | ||
7e933b61 | 7843 | -- Do not generate an elaboration check if the related subprogram is |
7844 | -- not subjected to accessibility checks. | |
7845 | ||
7846 | elsif Elaboration_Checks_Suppressed (Subp_Id) then | |
7847 | return; | |
f0e731f2 | 7848 | |
7849 | -- Do not generate an elaboration check if such code is not desirable | |
7850 | ||
7851 | elsif Restriction_Active (No_Elaboration_Code) then | |
7852 | return; | |
7e933b61 | 7853 | |
7854 | -- Do not consider subprograms which act as compilation units, because | |
7855 | -- they cannot be the target of a dispatching call. | |
7856 | ||
7857 | elsif Nkind (Context) = N_Compilation_Unit then | |
7858 | return; | |
7859 | ||
7860 | -- Only nonabstract library-level source primitives are considered for | |
7861 | -- this check. | |
7862 | ||
7863 | elsif not | |
7864 | (Comes_From_Source (Subp_Id) | |
7865 | and then Is_Library_Level_Entity (Subp_Id) | |
7866 | and then Is_Primitive (Subp_Id) | |
7867 | and then not Is_Abstract_Subprogram (Subp_Id)) | |
7868 | then | |
7869 | return; | |
7870 | ||
7871 | -- Do not consider inlined primitives, because once the body is inlined | |
7872 | -- the reference to the elaboration flag will be out of place and will | |
7873 | -- result in an undefined symbol. | |
7874 | ||
7875 | elsif Is_Inlined (Subp_Id) or else Has_Pragma_Inline (Subp_Id) then | |
7876 | return; | |
7877 | ||
7878 | -- Do not generate a duplicate elaboration check. This happens only in | |
7879 | -- the case of primitives completed by an expression function, as the | |
7880 | -- corresponding body is apparently analyzed and expanded twice. | |
7881 | ||
7882 | elsif Analyzed (Subp_Body) then | |
7883 | return; | |
7884 | ||
7885 | -- Do not consider primitives which occur within an instance that acts | |
7886 | -- as a compilation unit. Such an instance defines its spec and body out | |
7887 | -- of order (body is first) within the tree, which causes the reference | |
7888 | -- to the elaboration flag to appear as an undefined symbol. | |
7889 | ||
7890 | elsif Within_Compilation_Unit_Instance (Subp_Id) then | |
7891 | return; | |
7892 | end if; | |
7893 | ||
7894 | Tag_Typ := Find_Dispatching_Type (Subp_Id); | |
7895 | ||
7896 | -- Only tagged primitives may be the target of a dispatching call | |
7897 | ||
7898 | if No (Tag_Typ) then | |
7899 | return; | |
7900 | ||
7901 | -- Do not consider finalization-related primitives, because they may | |
7902 | -- need to be called while elaboration is taking place. | |
7903 | ||
7904 | elsif Is_Controlled (Tag_Typ) | |
7905 | and then Nam_In (Chars (Subp_Id), Name_Adjust, | |
7906 | Name_Finalize, | |
7907 | Name_Initialize) | |
7908 | then | |
7909 | return; | |
7910 | end if; | |
7911 | ||
7912 | -- Create the declaration of the elaboration flag. The name carries a | |
7913 | -- unique counter in case of name overloading. | |
7914 | ||
7915 | Flag_Id := | |
7916 | Make_Defining_Identifier (Loc, | |
7917 | Chars => New_External_Name (Chars (Subp_Id), 'F', -1)); | |
7918 | Set_Is_Frozen (Flag_Id); | |
7919 | ||
7920 | -- Insert the declaration of the elaboration flag in front of the | |
7921 | -- primitive spec and analyze it in the proper context. | |
7922 | ||
7923 | Push_Scope (Scope (Subp_Id)); | |
7924 | ||
7925 | -- Generate: | |
7926 | -- F : Boolean := False; | |
7927 | ||
7928 | Insert_Action (Subp_Decl, | |
7929 | Make_Object_Declaration (Loc, | |
7930 | Defining_Identifier => Flag_Id, | |
7931 | Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc), | |
7932 | Expression => New_Occurrence_Of (Standard_False, Loc))); | |
7933 | Pop_Scope; | |
7934 | ||
7935 | -- Prevent the compiler from optimizing the elaboration check by killing | |
7936 | -- the current value of the flag and the associated assignment. | |
7937 | ||
7938 | Set_Current_Value (Flag_Id, Empty); | |
7939 | Set_Last_Assignment (Flag_Id, Empty); | |
7940 | ||
7941 | -- Add a check at the top of the body declarations to ensure that the | |
7942 | -- elaboration flag has been set. | |
7943 | ||
7944 | Decls := Declarations (Subp_Body); | |
7945 | ||
7946 | if No (Decls) then | |
7947 | Decls := New_List; | |
7948 | Set_Declarations (Subp_Body, Decls); | |
7949 | end if; | |
7950 | ||
7951 | -- Generate: | |
7952 | -- if not F then | |
7953 | -- raise Program_Error with "access before elaboration"; | |
7954 | -- end if; | |
7955 | ||
7956 | Prepend_To (Decls, | |
7957 | Make_Raise_Program_Error (Loc, | |
7958 | Condition => | |
7959 | Make_Op_Not (Loc, | |
7960 | Right_Opnd => New_Occurrence_Of (Flag_Id, Loc)), | |
7961 | Reason => PE_Access_Before_Elaboration)); | |
7962 | ||
7963 | Analyze (First (Decls)); | |
7964 | ||
7965 | -- Set the elaboration flag once the body has been elaborated. Insert | |
7966 | -- the statement after the subprogram stub when the primitive body is | |
7967 | -- a subunit. | |
7968 | ||
7969 | if Nkind (Context) = N_Subunit then | |
7970 | Set_Ins := Corresponding_Stub (Context); | |
7971 | else | |
7972 | Set_Ins := Subp_Body; | |
7973 | end if; | |
7974 | ||
7975 | -- Generate: | |
7976 | -- F := True; | |
7977 | ||
7978 | Insert_After_And_Analyze (Set_Ins, | |
7979 | Make_Assignment_Statement (Loc, | |
7980 | Name => New_Occurrence_Of (Flag_Id, Loc), | |
7981 | Expression => New_Occurrence_Of (Standard_True, Loc))); | |
7982 | end Install_Primitive_Elaboration_Check; | |
7983 | ||
ee6ba406 | 7984 | -------------------------- |
7985 | -- Install_Static_Check -- | |
7986 | -------------------------- | |
7987 | ||
7988 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is | |
cda40848 | 7989 | Stat : constant Boolean := Is_OK_Static_Expression (R_Cno); |
ee6ba406 | 7990 | Typ : constant Entity_Id := Etype (R_Cno); |
7991 | ||
7992 | begin | |
f15731c4 | 7993 | Rewrite (R_Cno, |
7994 | Make_Raise_Constraint_Error (Loc, | |
7995 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 7996 | Set_Analyzed (R_Cno); |
7997 | Set_Etype (R_Cno, Typ); | |
7998 | Set_Raises_Constraint_Error (R_Cno); | |
7999 | Set_Is_Static_Expression (R_Cno, Stat); | |
840ab274 | 8000 | |
8001 | -- Now deal with possible local raise handling | |
8002 | ||
8003 | Possible_Local_Raise (R_Cno, Standard_Constraint_Error); | |
ee6ba406 | 8004 | end Install_Static_Check; |
8005 | ||
3cce7f32 | 8006 | ------------------------- |
8007 | -- Is_Check_Suppressed -- | |
8008 | ------------------------- | |
8009 | ||
8010 | function Is_Check_Suppressed (E : Entity_Id; C : Check_Id) return Boolean is | |
8011 | Ptr : Suppress_Stack_Entry_Ptr; | |
8012 | ||
8013 | begin | |
8014 | -- First search the local entity suppress stack. We search this from the | |
8015 | -- top of the stack down so that we get the innermost entry that applies | |
8016 | -- to this case if there are nested entries. | |
8017 | ||
8018 | Ptr := Local_Suppress_Stack_Top; | |
8019 | while Ptr /= null loop | |
8020 | if (Ptr.Entity = Empty or else Ptr.Entity = E) | |
8021 | and then (Ptr.Check = All_Checks or else Ptr.Check = C) | |
8022 | then | |
8023 | return Ptr.Suppress; | |
8024 | end if; | |
8025 | ||
8026 | Ptr := Ptr.Prev; | |
8027 | end loop; | |
8028 | ||
8029 | -- Now search the global entity suppress table for a matching entry. | |
8030 | -- We also search this from the top down so that if there are multiple | |
8031 | -- pragmas for the same entity, the last one applies (not clear what | |
8032 | -- or whether the RM specifies this handling, but it seems reasonable). | |
8033 | ||
8034 | Ptr := Global_Suppress_Stack_Top; | |
8035 | while Ptr /= null loop | |
8036 | if (Ptr.Entity = Empty or else Ptr.Entity = E) | |
8037 | and then (Ptr.Check = All_Checks or else Ptr.Check = C) | |
8038 | then | |
8039 | return Ptr.Suppress; | |
8040 | end if; | |
8041 | ||
8042 | Ptr := Ptr.Prev; | |
8043 | end loop; | |
8044 | ||
8045 | -- If we did not find a matching entry, then use the normal scope | |
8046 | -- suppress value after all (actually this will be the global setting | |
8047 | -- since it clearly was not overridden at any point). For a predefined | |
8048 | -- check, we test the specific flag. For a user defined check, we check | |
8049 | -- the All_Checks flag. The Overflow flag requires special handling to | |
8050 | -- deal with the General vs Assertion case | |
8051 | ||
8052 | if C = Overflow_Check then | |
8053 | return Overflow_Checks_Suppressed (Empty); | |
8054 | elsif C in Predefined_Check_Id then | |
8055 | return Scope_Suppress.Suppress (C); | |
8056 | else | |
8057 | return Scope_Suppress.Suppress (All_Checks); | |
8058 | end if; | |
8059 | end Is_Check_Suppressed; | |
8060 | ||
9dfe12ae | 8061 | --------------------- |
8062 | -- Kill_All_Checks -- | |
8063 | --------------------- | |
8064 | ||
8065 | procedure Kill_All_Checks is | |
8066 | begin | |
8067 | if Debug_Flag_CC then | |
8068 | w ("Kill_All_Checks"); | |
8069 | end if; | |
8070 | ||
feff2f05 | 8071 | -- We reset the number of saved checks to zero, and also modify all |
8072 | -- stack entries for statement ranges to indicate that the number of | |
8073 | -- checks at each level is now zero. | |
9dfe12ae | 8074 | |
8075 | Num_Saved_Checks := 0; | |
8076 | ||
96da3284 | 8077 | -- Note: the Int'Min here avoids any possibility of J being out of |
8078 | -- range when called from e.g. Conditional_Statements_Begin. | |
8079 | ||
8080 | for J in 1 .. Int'Min (Saved_Checks_TOS, Saved_Checks_Stack'Last) loop | |
9dfe12ae | 8081 | Saved_Checks_Stack (J) := 0; |
8082 | end loop; | |
8083 | end Kill_All_Checks; | |
8084 | ||
8085 | ----------------- | |
8086 | -- Kill_Checks -- | |
8087 | ----------------- | |
8088 | ||
8089 | procedure Kill_Checks (V : Entity_Id) is | |
8090 | begin | |
8091 | if Debug_Flag_CC then | |
8092 | w ("Kill_Checks for entity", Int (V)); | |
8093 | end if; | |
8094 | ||
8095 | for J in 1 .. Num_Saved_Checks loop | |
8096 | if Saved_Checks (J).Entity = V then | |
8097 | if Debug_Flag_CC then | |
8098 | w (" Checks killed for saved check ", J); | |
8099 | end if; | |
8100 | ||
8101 | Saved_Checks (J).Killed := True; | |
8102 | end if; | |
8103 | end loop; | |
8104 | end Kill_Checks; | |
8105 | ||
ee6ba406 | 8106 | ------------------------------ |
8107 | -- Length_Checks_Suppressed -- | |
8108 | ------------------------------ | |
8109 | ||
8110 | function Length_Checks_Suppressed (E : Entity_Id) return Boolean is | |
8111 | begin | |
9dfe12ae | 8112 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
8113 | return Is_Check_Suppressed (E, Length_Check); | |
8114 | else | |
fafc6b97 | 8115 | return Scope_Suppress.Suppress (Length_Check); |
9dfe12ae | 8116 | end if; |
ee6ba406 | 8117 | end Length_Checks_Suppressed; |
8118 | ||
3cce7f32 | 8119 | ----------------------- |
8120 | -- Make_Bignum_Block -- | |
8121 | ----------------------- | |
8122 | ||
8123 | function Make_Bignum_Block (Loc : Source_Ptr) return Node_Id is | |
8124 | M : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uM); | |
3cce7f32 | 8125 | begin |
8126 | return | |
8127 | Make_Block_Statement (Loc, | |
97c15ab0 | 8128 | Declarations => |
8129 | New_List (Build_SS_Mark_Call (Loc, M)), | |
3cce7f32 | 8130 | Handled_Statement_Sequence => |
8131 | Make_Handled_Sequence_Of_Statements (Loc, | |
97c15ab0 | 8132 | Statements => New_List (Build_SS_Release_Call (Loc, M)))); |
3cce7f32 | 8133 | end Make_Bignum_Block; |
8134 | ||
0df9d43f | 8135 | ---------------------------------- |
8136 | -- Minimize_Eliminate_Overflows -- | |
8137 | ---------------------------------- | |
3cce7f32 | 8138 | |
f32c377d | 8139 | -- This is a recursive routine that is called at the top of an expression |
8140 | -- tree to properly process overflow checking for a whole subtree by making | |
8141 | -- recursive calls to process operands. This processing may involve the use | |
8142 | -- of bignum or long long integer arithmetic, which will change the types | |
8143 | -- of operands and results. That's why we can't do this bottom up (since | |
21a55437 | 8144 | -- it would interfere with semantic analysis). |
f32c377d | 8145 | |
21a55437 | 8146 | -- What happens is that if MINIMIZED/ELIMINATED mode is in effect then |
0df9d43f | 8147 | -- the operator expansion routines, as well as the expansion routines for |
8148 | -- if/case expression, do nothing (for the moment) except call the routine | |
8149 | -- to apply the overflow check (Apply_Arithmetic_Overflow_Check). That | |
8150 | -- routine does nothing for non top-level nodes, so at the point where the | |
8151 | -- call is made for the top level node, the entire expression subtree has | |
8152 | -- not been expanded, or processed for overflow. All that has to happen as | |
8153 | -- a result of the top level call to this routine. | |
f32c377d | 8154 | |
8155 | -- As noted above, the overflow processing works by making recursive calls | |
8156 | -- for the operands, and figuring out what to do, based on the processing | |
8157 | -- of these operands (e.g. if a bignum operand appears, the parent op has | |
8158 | -- to be done in bignum mode), and the determined ranges of the operands. | |
8159 | ||
8160 | -- After possible rewriting of a constituent subexpression node, a call is | |
4fb5f0a0 | 8161 | -- made to either reexpand the node (if nothing has changed) or reanalyze |
21a55437 | 8162 | -- the node (if it has been modified by the overflow check processing). The |
8163 | -- Analyzed_Flag is set to False before the reexpand/reanalyze. To avoid | |
8164 | -- a recursive call into the whole overflow apparatus, an important rule | |
0df9d43f | 8165 | -- for this call is that the overflow handling mode must be temporarily set |
8166 | -- to STRICT. | |
f32c377d | 8167 | |
0df9d43f | 8168 | procedure Minimize_Eliminate_Overflows |
61016a7a | 8169 | (N : Node_Id; |
8170 | Lo : out Uint; | |
8171 | Hi : out Uint; | |
8172 | Top_Level : Boolean) | |
3cce7f32 | 8173 | is |
0326b4d4 | 8174 | Rtyp : constant Entity_Id := Etype (N); |
8175 | pragma Assert (Is_Signed_Integer_Type (Rtyp)); | |
8176 | -- Result type, must be a signed integer type | |
3cce7f32 | 8177 | |
db415383 | 8178 | Check_Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
3cce7f32 | 8179 | pragma Assert (Check_Mode in Minimized_Or_Eliminated); |
8180 | ||
8181 | Loc : constant Source_Ptr := Sloc (N); | |
8182 | ||
8183 | Rlo, Rhi : Uint; | |
0326b4d4 | 8184 | -- Ranges of values for right operand (operator case) |
3cce7f32 | 8185 | |
16149377 | 8186 | Llo : Uint := No_Uint; -- initialize to prevent warning |
8187 | Lhi : Uint := No_Uint; -- initialize to prevent warning | |
0326b4d4 | 8188 | -- Ranges of values for left operand (operator case) |
3cce7f32 | 8189 | |
49b3a812 | 8190 | LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); |
8191 | -- Operands and results are of this type when we convert | |
8192 | ||
0326b4d4 | 8193 | LLLo : constant Uint := Intval (Type_Low_Bound (LLIB)); |
8194 | LLHi : constant Uint := Intval (Type_High_Bound (LLIB)); | |
3cce7f32 | 8195 | -- Bounds of Long_Long_Integer |
8196 | ||
8197 | Binary : constant Boolean := Nkind (N) in N_Binary_Op; | |
8198 | -- Indicates binary operator case | |
8199 | ||
8200 | OK : Boolean; | |
8201 | -- Used in call to Determine_Range | |
8202 | ||
61016a7a | 8203 | Bignum_Operands : Boolean; |
8204 | -- Set True if one or more operands is already of type Bignum, meaning | |
8205 | -- that for sure (regardless of Top_Level setting) we are committed to | |
0326b4d4 | 8206 | -- doing the operation in Bignum mode (or in the case of a case or if |
21a55437 | 8207 | -- expression, converting all the dependent expressions to Bignum). |
0326b4d4 | 8208 | |
8209 | Long_Long_Integer_Operands : Boolean; | |
21a55437 | 8210 | -- Set True if one or more operands is already of type Long_Long_Integer |
0326b4d4 | 8211 | -- which means that if the result is known to be in the result type |
8212 | -- range, then we must convert such operands back to the result type. | |
0df9d43f | 8213 | |
8214 | procedure Reanalyze (Typ : Entity_Id; Suppress : Boolean := False); | |
8215 | -- This is called when we have modified the node and we therefore need | |
8216 | -- to reanalyze it. It is important that we reset the mode to STRICT for | |
8217 | -- this reanalysis, since if we leave it in MINIMIZED or ELIMINATED mode | |
39a0c1d3 | 8218 | -- we would reenter this routine recursively which would not be good. |
0df9d43f | 8219 | -- The argument Suppress is set True if we also want to suppress |
8220 | -- overflow checking for the reexpansion (this is set when we know | |
8221 | -- overflow is not possible). Typ is the type for the reanalysis. | |
8222 | ||
8223 | procedure Reexpand (Suppress : Boolean := False); | |
8224 | -- This is like Reanalyze, but does not do the Analyze step, it only | |
8225 | -- does a reexpansion. We do this reexpansion in STRICT mode, so that | |
8226 | -- instead of reentering the MINIMIZED/ELIMINATED mode processing, we | |
8227 | -- follow the normal expansion path (e.g. converting A**4 to A**2**2). | |
8228 | -- Note that skipping reanalysis is not just an optimization, testing | |
8229 | -- has showed up several complex cases in which reanalyzing an already | |
8230 | -- analyzed node causes incorrect behavior. | |
4fb5f0a0 | 8231 | |
0326b4d4 | 8232 | function In_Result_Range return Boolean; |
8233 | -- Returns True iff Lo .. Hi are within range of the result type | |
61016a7a | 8234 | |
2fe22c69 | 8235 | procedure Max (A : in out Uint; B : Uint); |
21a55437 | 8236 | -- If A is No_Uint, sets A to B, else to UI_Max (A, B) |
2fe22c69 | 8237 | |
8238 | procedure Min (A : in out Uint; B : Uint); | |
21a55437 | 8239 | -- If A is No_Uint, sets A to B, else to UI_Min (A, B) |
2fe22c69 | 8240 | |
0326b4d4 | 8241 | --------------------- |
8242 | -- In_Result_Range -- | |
8243 | --------------------- | |
8244 | ||
8245 | function In_Result_Range return Boolean is | |
8246 | begin | |
f32c377d | 8247 | if Lo = No_Uint or else Hi = No_Uint then |
8248 | return False; | |
8249 | ||
cda40848 | 8250 | elsif Is_OK_Static_Subtype (Etype (N)) then |
0326b4d4 | 8251 | return Lo >= Expr_Value (Type_Low_Bound (Rtyp)) |
8252 | and then | |
8253 | Hi <= Expr_Value (Type_High_Bound (Rtyp)); | |
f32c377d | 8254 | |
0326b4d4 | 8255 | else |
8256 | return Lo >= Expr_Value (Type_Low_Bound (Base_Type (Rtyp))) | |
8257 | and then | |
8258 | Hi <= Expr_Value (Type_High_Bound (Base_Type (Rtyp))); | |
8259 | end if; | |
8260 | end In_Result_Range; | |
8261 | ||
2fe22c69 | 8262 | --------- |
8263 | -- Max -- | |
8264 | --------- | |
8265 | ||
8266 | procedure Max (A : in out Uint; B : Uint) is | |
8267 | begin | |
8268 | if A = No_Uint or else B > A then | |
8269 | A := B; | |
8270 | end if; | |
8271 | end Max; | |
8272 | ||
8273 | --------- | |
8274 | -- Min -- | |
8275 | --------- | |
8276 | ||
8277 | procedure Min (A : in out Uint; B : Uint) is | |
8278 | begin | |
8279 | if A = No_Uint or else B < A then | |
8280 | A := B; | |
8281 | end if; | |
8282 | end Min; | |
8283 | ||
0df9d43f | 8284 | --------------- |
8285 | -- Reanalyze -- | |
8286 | --------------- | |
8287 | ||
8288 | procedure Reanalyze (Typ : Entity_Id; Suppress : Boolean := False) is | |
db415383 | 8289 | Svg : constant Overflow_Mode_Type := |
8290 | Scope_Suppress.Overflow_Mode_General; | |
8291 | Sva : constant Overflow_Mode_Type := | |
8292 | Scope_Suppress.Overflow_Mode_Assertions; | |
0df9d43f | 8293 | Svo : constant Boolean := |
8294 | Scope_Suppress.Suppress (Overflow_Check); | |
8295 | ||
8296 | begin | |
db415383 | 8297 | Scope_Suppress.Overflow_Mode_General := Strict; |
8298 | Scope_Suppress.Overflow_Mode_Assertions := Strict; | |
0df9d43f | 8299 | |
8300 | if Suppress then | |
8301 | Scope_Suppress.Suppress (Overflow_Check) := True; | |
8302 | end if; | |
8303 | ||
8304 | Analyze_And_Resolve (N, Typ); | |
8305 | ||
2b108e18 | 8306 | Scope_Suppress.Suppress (Overflow_Check) := Svo; |
8307 | Scope_Suppress.Overflow_Mode_General := Svg; | |
8308 | Scope_Suppress.Overflow_Mode_Assertions := Sva; | |
0df9d43f | 8309 | end Reanalyze; |
8310 | ||
4fb5f0a0 | 8311 | -------------- |
8312 | -- Reexpand -- | |
8313 | -------------- | |
8314 | ||
0df9d43f | 8315 | procedure Reexpand (Suppress : Boolean := False) is |
db415383 | 8316 | Svg : constant Overflow_Mode_Type := |
8317 | Scope_Suppress.Overflow_Mode_General; | |
8318 | Sva : constant Overflow_Mode_Type := | |
8319 | Scope_Suppress.Overflow_Mode_Assertions; | |
0df9d43f | 8320 | Svo : constant Boolean := |
8321 | Scope_Suppress.Suppress (Overflow_Check); | |
8322 | ||
4fb5f0a0 | 8323 | begin |
db415383 | 8324 | Scope_Suppress.Overflow_Mode_General := Strict; |
8325 | Scope_Suppress.Overflow_Mode_Assertions := Strict; | |
4fb5f0a0 | 8326 | Set_Analyzed (N, False); |
0df9d43f | 8327 | |
8328 | if Suppress then | |
8329 | Scope_Suppress.Suppress (Overflow_Check) := True; | |
8330 | end if; | |
8331 | ||
4fb5f0a0 | 8332 | Expand (N); |
0df9d43f | 8333 | |
2b108e18 | 8334 | Scope_Suppress.Suppress (Overflow_Check) := Svo; |
8335 | Scope_Suppress.Overflow_Mode_General := Svg; | |
8336 | Scope_Suppress.Overflow_Mode_Assertions := Sva; | |
4fb5f0a0 | 8337 | end Reexpand; |
8338 | ||
0df9d43f | 8339 | -- Start of processing for Minimize_Eliminate_Overflows |
2fe22c69 | 8340 | |
3cce7f32 | 8341 | begin |
0326b4d4 | 8342 | -- Case where we do not have a signed integer arithmetic operation |
3cce7f32 | 8343 | |
8344 | if not Is_Signed_Integer_Arithmetic_Op (N) then | |
8345 | ||
8346 | -- Use the normal Determine_Range routine to get the range. We | |
8347 | -- don't require operands to be valid, invalid values may result in | |
8348 | -- rubbish results where the result has not been properly checked for | |
39a0c1d3 | 8349 | -- overflow, that's fine. |
3cce7f32 | 8350 | |
8351 | Determine_Range (N, OK, Lo, Hi, Assume_Valid => False); | |
8352 | ||
21a55437 | 8353 | -- If Determine_Range did not work (can this in fact happen? Not |
3cce7f32 | 8354 | -- clear but might as well protect), use type bounds. |
8355 | ||
8356 | if not OK then | |
8357 | Lo := Intval (Type_Low_Bound (Base_Type (Etype (N)))); | |
8358 | Hi := Intval (Type_High_Bound (Base_Type (Etype (N)))); | |
8359 | end if; | |
8360 | ||
8361 | -- If we don't have a binary operator, all we have to do is to set | |
20cf157b | 8362 | -- the Hi/Lo range, so we are done. |
3cce7f32 | 8363 | |
8364 | return; | |
8365 | ||
0326b4d4 | 8366 | -- Processing for if expression |
8367 | ||
92f1631f | 8368 | elsif Nkind (N) = N_If_Expression then |
0326b4d4 | 8369 | declare |
8370 | Then_DE : constant Node_Id := Next (First (Expressions (N))); | |
8371 | Else_DE : constant Node_Id := Next (Then_DE); | |
8372 | ||
8373 | begin | |
8374 | Bignum_Operands := False; | |
8375 | ||
0df9d43f | 8376 | Minimize_Eliminate_Overflows |
0326b4d4 | 8377 | (Then_DE, Lo, Hi, Top_Level => False); |
8378 | ||
8379 | if Lo = No_Uint then | |
8380 | Bignum_Operands := True; | |
8381 | end if; | |
8382 | ||
0df9d43f | 8383 | Minimize_Eliminate_Overflows |
0326b4d4 | 8384 | (Else_DE, Rlo, Rhi, Top_Level => False); |
8385 | ||
8386 | if Rlo = No_Uint then | |
8387 | Bignum_Operands := True; | |
8388 | else | |
8389 | Long_Long_Integer_Operands := | |
8390 | Etype (Then_DE) = LLIB or else Etype (Else_DE) = LLIB; | |
8391 | ||
8392 | Min (Lo, Rlo); | |
8393 | Max (Hi, Rhi); | |
8394 | end if; | |
8395 | ||
21a55437 | 8396 | -- If at least one of our operands is now Bignum, we must rebuild |
8397 | -- the if expression to use Bignum operands. We will analyze the | |
0326b4d4 | 8398 | -- rebuilt if expression with overflow checks off, since once we |
39a0c1d3 | 8399 | -- are in bignum mode, we are all done with overflow checks. |
0326b4d4 | 8400 | |
8401 | if Bignum_Operands then | |
8402 | Rewrite (N, | |
92f1631f | 8403 | Make_If_Expression (Loc, |
0326b4d4 | 8404 | Expressions => New_List ( |
8405 | Remove_Head (Expressions (N)), | |
8406 | Convert_To_Bignum (Then_DE), | |
8407 | Convert_To_Bignum (Else_DE)), | |
8408 | Is_Elsif => Is_Elsif (N))); | |
8409 | ||
0df9d43f | 8410 | Reanalyze (RTE (RE_Bignum), Suppress => True); |
0326b4d4 | 8411 | |
8412 | -- If we have no Long_Long_Integer operands, then we are in result | |
8413 | -- range, since it means that none of our operands felt the need | |
8414 | -- to worry about overflow (otherwise it would have already been | |
4fb5f0a0 | 8415 | -- converted to long long integer or bignum). We reexpand to |
8416 | -- complete the expansion of the if expression (but we do not | |
8417 | -- need to reanalyze). | |
0326b4d4 | 8418 | |
8419 | elsif not Long_Long_Integer_Operands then | |
8420 | Set_Do_Overflow_Check (N, False); | |
0df9d43f | 8421 | Reexpand; |
0326b4d4 | 8422 | |
8423 | -- Otherwise convert us to long long integer mode. Note that we | |
8424 | -- don't need any further overflow checking at this level. | |
8425 | ||
8426 | else | |
8427 | Convert_To_And_Rewrite (LLIB, Then_DE); | |
8428 | Convert_To_And_Rewrite (LLIB, Else_DE); | |
8429 | Set_Etype (N, LLIB); | |
f32c377d | 8430 | |
8431 | -- Now reanalyze with overflow checks off | |
8432 | ||
0326b4d4 | 8433 | Set_Do_Overflow_Check (N, False); |
0df9d43f | 8434 | Reanalyze (LLIB, Suppress => True); |
0326b4d4 | 8435 | end if; |
8436 | end; | |
8437 | ||
8438 | return; | |
8439 | ||
8440 | -- Here for case expression | |
8441 | ||
8442 | elsif Nkind (N) = N_Case_Expression then | |
8443 | Bignum_Operands := False; | |
8444 | Long_Long_Integer_Operands := False; | |
0326b4d4 | 8445 | |
8446 | declare | |
f32c377d | 8447 | Alt : Node_Id; |
0326b4d4 | 8448 | |
8449 | begin | |
8450 | -- Loop through expressions applying recursive call | |
8451 | ||
8452 | Alt := First (Alternatives (N)); | |
8453 | while Present (Alt) loop | |
8454 | declare | |
8455 | Aexp : constant Node_Id := Expression (Alt); | |
8456 | ||
8457 | begin | |
0df9d43f | 8458 | Minimize_Eliminate_Overflows |
0326b4d4 | 8459 | (Aexp, Lo, Hi, Top_Level => False); |
8460 | ||
8461 | if Lo = No_Uint then | |
8462 | Bignum_Operands := True; | |
8463 | elsif Etype (Aexp) = LLIB then | |
8464 | Long_Long_Integer_Operands := True; | |
8465 | end if; | |
8466 | end; | |
8467 | ||
8468 | Next (Alt); | |
8469 | end loop; | |
8470 | ||
8471 | -- If we have no bignum or long long integer operands, it means | |
8472 | -- that none of our dependent expressions could raise overflow. | |
8473 | -- In this case, we simply return with no changes except for | |
8474 | -- resetting the overflow flag, since we are done with overflow | |
4fb5f0a0 | 8475 | -- checks for this node. We will reexpand to get the needed |
8476 | -- expansion for the case expression, but we do not need to | |
21a55437 | 8477 | -- reanalyze, since nothing has changed. |
0326b4d4 | 8478 | |
f32c377d | 8479 | if not (Bignum_Operands or Long_Long_Integer_Operands) then |
0326b4d4 | 8480 | Set_Do_Overflow_Check (N, False); |
0df9d43f | 8481 | Reexpand (Suppress => True); |
0326b4d4 | 8482 | |
8483 | -- Otherwise we are going to rebuild the case expression using | |
8484 | -- either bignum or long long integer operands throughout. | |
8485 | ||
8486 | else | |
f32c377d | 8487 | declare |
8488 | Rtype : Entity_Id; | |
16149377 | 8489 | pragma Warnings (Off, Rtype); |
f32c377d | 8490 | New_Alts : List_Id; |
8491 | New_Exp : Node_Id; | |
8492 | ||
8493 | begin | |
8494 | New_Alts := New_List; | |
8495 | Alt := First (Alternatives (N)); | |
8496 | while Present (Alt) loop | |
8497 | if Bignum_Operands then | |
8498 | New_Exp := Convert_To_Bignum (Expression (Alt)); | |
8499 | Rtype := RTE (RE_Bignum); | |
8500 | else | |
8501 | New_Exp := Convert_To (LLIB, Expression (Alt)); | |
8502 | Rtype := LLIB; | |
8503 | end if; | |
0326b4d4 | 8504 | |
f32c377d | 8505 | Append_To (New_Alts, |
8506 | Make_Case_Expression_Alternative (Sloc (Alt), | |
8507 | Actions => No_List, | |
8508 | Discrete_Choices => Discrete_Choices (Alt), | |
8509 | Expression => New_Exp)); | |
0326b4d4 | 8510 | |
f32c377d | 8511 | Next (Alt); |
8512 | end loop; | |
0326b4d4 | 8513 | |
f32c377d | 8514 | Rewrite (N, |
8515 | Make_Case_Expression (Loc, | |
8516 | Expression => Expression (N), | |
8517 | Alternatives => New_Alts)); | |
0326b4d4 | 8518 | |
0df9d43f | 8519 | Reanalyze (Rtype, Suppress => True); |
f32c377d | 8520 | end; |
0326b4d4 | 8521 | end if; |
8522 | end; | |
8523 | ||
8524 | return; | |
8525 | end if; | |
8526 | ||
8527 | -- If we have an arithmetic operator we make recursive calls on the | |
3cce7f32 | 8528 | -- operands to get the ranges (and to properly process the subtree |
20cf157b | 8529 | -- that lies below us). |
3cce7f32 | 8530 | |
0df9d43f | 8531 | Minimize_Eliminate_Overflows |
0326b4d4 | 8532 | (Right_Opnd (N), Rlo, Rhi, Top_Level => False); |
3cce7f32 | 8533 | |
0326b4d4 | 8534 | if Binary then |
0df9d43f | 8535 | Minimize_Eliminate_Overflows |
0326b4d4 | 8536 | (Left_Opnd (N), Llo, Lhi, Top_Level => False); |
3cce7f32 | 8537 | end if; |
8538 | ||
f32c377d | 8539 | -- Record if we have Long_Long_Integer operands |
8540 | ||
8541 | Long_Long_Integer_Operands := | |
8542 | Etype (Right_Opnd (N)) = LLIB | |
8543 | or else (Binary and then Etype (Left_Opnd (N)) = LLIB); | |
8544 | ||
8545 | -- If either operand is a bignum, then result will be a bignum and we | |
8546 | -- don't need to do any range analysis. As previously discussed we could | |
8547 | -- do range analysis in such cases, but it could mean working with giant | |
8548 | -- numbers at compile time for very little gain (the number of cases | |
21a55437 | 8549 | -- in which we could slip back from bignum mode is small). |
3cce7f32 | 8550 | |
8551 | if Rlo = No_Uint or else (Binary and then Llo = No_Uint) then | |
8552 | Lo := No_Uint; | |
8553 | Hi := No_Uint; | |
61016a7a | 8554 | Bignum_Operands := True; |
3cce7f32 | 8555 | |
8556 | -- Otherwise compute result range | |
8557 | ||
8558 | else | |
61016a7a | 8559 | Bignum_Operands := False; |
8560 | ||
3cce7f32 | 8561 | case Nkind (N) is |
8562 | ||
8563 | -- Absolute value | |
8564 | ||
8565 | when N_Op_Abs => | |
8566 | Lo := Uint_0; | |
de922300 | 8567 | Hi := UI_Max (abs Rlo, abs Rhi); |
3cce7f32 | 8568 | |
8569 | -- Addition | |
8570 | ||
8571 | when N_Op_Add => | |
8572 | Lo := Llo + Rlo; | |
8573 | Hi := Lhi + Rhi; | |
8574 | ||
8575 | -- Division | |
8576 | ||
8577 | when N_Op_Divide => | |
2fe22c69 | 8578 | |
5f4275e1 | 8579 | -- If the right operand can only be zero, set 0..0 |
2fe22c69 | 8580 | |
5f4275e1 | 8581 | if Rlo = 0 and then Rhi = 0 then |
8582 | Lo := Uint_0; | |
8583 | Hi := Uint_0; | |
2fe22c69 | 8584 | |
5f4275e1 | 8585 | -- Possible bounds of division must come from dividing end |
8586 | -- values of the input ranges (four possibilities), provided | |
8587 | -- zero is not included in the possible values of the right | |
8588 | -- operand. | |
8589 | ||
8590 | -- Otherwise, we just consider two intervals of values for | |
8591 | -- the right operand: the interval of negative values (up to | |
8592 | -- -1) and the interval of positive values (starting at 1). | |
8593 | -- Since division by 1 is the identity, and division by -1 | |
8594 | -- is negation, we get all possible bounds of division in that | |
8595 | -- case by considering: | |
8596 | -- - all values from the division of end values of input | |
8597 | -- ranges; | |
8598 | -- - the end values of the left operand; | |
8599 | -- - the negation of the end values of the left operand. | |
2fe22c69 | 8600 | |
5f4275e1 | 8601 | else |
8602 | declare | |
8603 | Mrk : constant Uintp.Save_Mark := Mark; | |
8604 | -- Mark so we can release the RR and Ev values | |
2fe22c69 | 8605 | |
5f4275e1 | 8606 | Ev1 : Uint; |
8607 | Ev2 : Uint; | |
8608 | Ev3 : Uint; | |
8609 | Ev4 : Uint; | |
2fe22c69 | 8610 | |
5f4275e1 | 8611 | begin |
8612 | -- Discard extreme values of zero for the divisor, since | |
8613 | -- they will simply result in an exception in any case. | |
2fe22c69 | 8614 | |
5f4275e1 | 8615 | if Rlo = 0 then |
8616 | Rlo := Uint_1; | |
8617 | elsif Rhi = 0 then | |
8618 | Rhi := -Uint_1; | |
2fe22c69 | 8619 | end if; |
2fe22c69 | 8620 | |
5f4275e1 | 8621 | -- Compute possible bounds coming from dividing end |
8622 | -- values of the input ranges. | |
2fe22c69 | 8623 | |
5f4275e1 | 8624 | Ev1 := Llo / Rlo; |
8625 | Ev2 := Llo / Rhi; | |
8626 | Ev3 := Lhi / Rlo; | |
8627 | Ev4 := Lhi / Rhi; | |
2fe22c69 | 8628 | |
5f4275e1 | 8629 | Lo := UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4)); |
8630 | Hi := UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4)); | |
2fe22c69 | 8631 | |
5f4275e1 | 8632 | -- If the right operand can be both negative or positive, |
8633 | -- include the end values of the left operand in the | |
8634 | -- extreme values, as well as their negation. | |
2fe22c69 | 8635 | |
5f4275e1 | 8636 | if Rlo < 0 and then Rhi > 0 then |
8637 | Ev1 := Llo; | |
8638 | Ev2 := -Llo; | |
8639 | Ev3 := Lhi; | |
8640 | Ev4 := -Lhi; | |
2fe22c69 | 8641 | |
5f4275e1 | 8642 | Min (Lo, |
8643 | UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4))); | |
8644 | Max (Hi, | |
8645 | UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4))); | |
2fe22c69 | 8646 | end if; |
2fe22c69 | 8647 | |
5f4275e1 | 8648 | -- Release the RR and Ev values |
2fe22c69 | 8649 | |
5f4275e1 | 8650 | Release_And_Save (Mrk, Lo, Hi); |
8651 | end; | |
8652 | end if; | |
3cce7f32 | 8653 | |
8654 | -- Exponentiation | |
8655 | ||
8656 | when N_Op_Expon => | |
de922300 | 8657 | |
8658 | -- Discard negative values for the exponent, since they will | |
8659 | -- simply result in an exception in any case. | |
8660 | ||
8661 | if Rhi < 0 then | |
8662 | Rhi := Uint_0; | |
8663 | elsif Rlo < 0 then | |
8664 | Rlo := Uint_0; | |
8665 | end if; | |
8666 | ||
8667 | -- Estimate number of bits in result before we go computing | |
8668 | -- giant useless bounds. Basically the number of bits in the | |
8669 | -- result is the number of bits in the base multiplied by the | |
8670 | -- value of the exponent. If this is big enough that the result | |
8671 | -- definitely won't fit in Long_Long_Integer, switch to bignum | |
8672 | -- mode immediately, and avoid computing giant bounds. | |
8673 | ||
8674 | -- The comparison here is approximate, but conservative, it | |
8675 | -- only clicks on cases that are sure to exceed the bounds. | |
8676 | ||
8677 | if Num_Bits (UI_Max (abs Llo, abs Lhi)) * Rhi + 1 > 100 then | |
8678 | Lo := No_Uint; | |
8679 | Hi := No_Uint; | |
8680 | ||
8681 | -- If right operand is zero then result is 1 | |
8682 | ||
8683 | elsif Rhi = 0 then | |
8684 | Lo := Uint_1; | |
8685 | Hi := Uint_1; | |
8686 | ||
8687 | else | |
8688 | -- High bound comes either from exponentiation of largest | |
5f4275e1 | 8689 | -- positive value to largest exponent value, or from |
8690 | -- the exponentiation of most negative value to an | |
8691 | -- even exponent. | |
de922300 | 8692 | |
8693 | declare | |
8694 | Hi1, Hi2 : Uint; | |
8695 | ||
8696 | begin | |
5f4275e1 | 8697 | if Lhi > 0 then |
de922300 | 8698 | Hi1 := Lhi ** Rhi; |
8699 | else | |
8700 | Hi1 := Uint_0; | |
8701 | end if; | |
8702 | ||
8703 | if Llo < 0 then | |
8704 | if Rhi mod 2 = 0 then | |
de922300 | 8705 | Hi2 := Llo ** Rhi; |
5f4275e1 | 8706 | else |
8707 | Hi2 := Llo ** (Rhi - 1); | |
de922300 | 8708 | end if; |
8709 | else | |
8710 | Hi2 := Uint_0; | |
8711 | end if; | |
8712 | ||
8713 | Hi := UI_Max (Hi1, Hi2); | |
8714 | end; | |
8715 | ||
8716 | -- Result can only be negative if base can be negative | |
8717 | ||
8718 | if Llo < 0 then | |
21a55437 | 8719 | if Rhi mod 2 = 0 then |
de922300 | 8720 | Lo := Llo ** (Rhi - 1); |
8721 | else | |
8722 | Lo := Llo ** Rhi; | |
8723 | end if; | |
8724 | ||
21a55437 | 8725 | -- Otherwise low bound is minimum ** minimum |
de922300 | 8726 | |
8727 | else | |
8728 | Lo := Llo ** Rlo; | |
8729 | end if; | |
8730 | end if; | |
3cce7f32 | 8731 | |
8732 | -- Negation | |
8733 | ||
8734 | when N_Op_Minus => | |
8735 | Lo := -Rhi; | |
8736 | Hi := -Rlo; | |
8737 | ||
8738 | -- Mod | |
8739 | ||
8740 | when N_Op_Mod => | |
2fe22c69 | 8741 | declare |
5f4275e1 | 8742 | Maxabs : constant Uint := UI_Max (abs Rlo, abs Rhi) - 1; |
2fe22c69 | 8743 | -- This is the maximum absolute value of the result |
8744 | ||
8745 | begin | |
8746 | Lo := Uint_0; | |
8747 | Hi := Uint_0; | |
8748 | ||
8749 | -- The result depends only on the sign and magnitude of | |
8750 | -- the right operand, it does not depend on the sign or | |
8751 | -- magnitude of the left operand. | |
8752 | ||
8753 | if Rlo < 0 then | |
8754 | Lo := -Maxabs; | |
8755 | end if; | |
8756 | ||
8757 | if Rhi > 0 then | |
8758 | Hi := Maxabs; | |
8759 | end if; | |
8760 | end; | |
3cce7f32 | 8761 | |
8762 | -- Multiplication | |
8763 | ||
8764 | when N_Op_Multiply => | |
49b3a812 | 8765 | |
8766 | -- Possible bounds of multiplication must come from multiplying | |
8767 | -- end values of the input ranges (four possibilities). | |
8768 | ||
8769 | declare | |
8770 | Mrk : constant Uintp.Save_Mark := Mark; | |
8771 | -- Mark so we can release the Ev values | |
8772 | ||
8773 | Ev1 : constant Uint := Llo * Rlo; | |
8774 | Ev2 : constant Uint := Llo * Rhi; | |
8775 | Ev3 : constant Uint := Lhi * Rlo; | |
8776 | Ev4 : constant Uint := Lhi * Rhi; | |
8777 | ||
8778 | begin | |
8779 | Lo := UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4)); | |
8780 | Hi := UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4)); | |
8781 | ||
8782 | -- Release the Ev values | |
8783 | ||
8784 | Release_And_Save (Mrk, Lo, Hi); | |
8785 | end; | |
3cce7f32 | 8786 | |
8787 | -- Plus operator (affirmation) | |
8788 | ||
8789 | when N_Op_Plus => | |
8790 | Lo := Rlo; | |
8791 | Hi := Rhi; | |
8792 | ||
8793 | -- Remainder | |
8794 | ||
8795 | when N_Op_Rem => | |
2fe22c69 | 8796 | declare |
5f4275e1 | 8797 | Maxabs : constant Uint := UI_Max (abs Rlo, abs Rhi) - 1; |
2fe22c69 | 8798 | -- This is the maximum absolute value of the result. Note |
5f4275e1 | 8799 | -- that the result range does not depend on the sign of the |
8800 | -- right operand. | |
2fe22c69 | 8801 | |
8802 | begin | |
8803 | Lo := Uint_0; | |
8804 | Hi := Uint_0; | |
8805 | ||
8806 | -- Case of left operand negative, which results in a range | |
8807 | -- of -Maxabs .. 0 for those negative values. If there are | |
8808 | -- no negative values then Lo value of result is always 0. | |
8809 | ||
8810 | if Llo < 0 then | |
8811 | Lo := -Maxabs; | |
8812 | end if; | |
8813 | ||
8814 | -- Case of left operand positive | |
8815 | ||
8816 | if Lhi > 0 then | |
8817 | Hi := Maxabs; | |
8818 | end if; | |
8819 | end; | |
3cce7f32 | 8820 | |
8821 | -- Subtract | |
8822 | ||
8823 | when N_Op_Subtract => | |
8824 | Lo := Llo - Rhi; | |
8825 | Hi := Lhi - Rlo; | |
8826 | ||
8827 | -- Nothing else should be possible | |
8828 | ||
8829 | when others => | |
8830 | raise Program_Error; | |
3cce7f32 | 8831 | end case; |
8832 | end if; | |
8833 | ||
4fb5f0a0 | 8834 | -- Here for the case where we have not rewritten anything (no bignum |
21a55437 | 8835 | -- operands or long long integer operands), and we know the result. |
8836 | -- If we know we are in the result range, and we do not have Bignum | |
8837 | -- operands or Long_Long_Integer operands, we can just reexpand with | |
8838 | -- overflow checks turned off (since we know we cannot have overflow). | |
8839 | -- As always the reexpansion is required to complete expansion of the | |
8840 | -- operator, but we do not need to reanalyze, and we prevent recursion | |
8841 | -- by suppressing the check. | |
f32c377d | 8842 | |
8843 | if not (Bignum_Operands or Long_Long_Integer_Operands) | |
8844 | and then In_Result_Range | |
8845 | then | |
8846 | Set_Do_Overflow_Check (N, False); | |
0df9d43f | 8847 | Reexpand (Suppress => True); |
f32c377d | 8848 | return; |
8849 | ||
8850 | -- Here we know that we are not in the result range, and in the general | |
21a55437 | 8851 | -- case we will move into either the Bignum or Long_Long_Integer domain |
8852 | -- to compute the result. However, there is one exception. If we are | |
8853 | -- at the top level, and we do not have Bignum or Long_Long_Integer | |
8854 | -- operands, we will have to immediately convert the result back to | |
8855 | -- the result type, so there is no point in Bignum/Long_Long_Integer | |
8856 | -- fiddling. | |
f32c377d | 8857 | |
8858 | elsif Top_Level | |
8859 | and then not (Bignum_Operands or Long_Long_Integer_Operands) | |
b6a8f264 | 8860 | |
8861 | -- One further refinement. If we are at the top level, but our parent | |
8862 | -- is a type conversion, then go into bignum or long long integer node | |
8863 | -- since the result will be converted to that type directly without | |
8864 | -- going through the result type, and we may avoid an overflow. This | |
8865 | -- is the case for example of Long_Long_Integer (A ** 4), where A is | |
8866 | -- of type Integer, and the result A ** 4 fits in Long_Long_Integer | |
8867 | -- but does not fit in Integer. | |
8868 | ||
8869 | and then Nkind (Parent (N)) /= N_Type_Conversion | |
f32c377d | 8870 | then |
0df9d43f | 8871 | -- Here keep original types, but we need to complete analysis |
f32c377d | 8872 | |
8873 | -- One subtlety. We can't just go ahead and do an analyze operation | |
21a55437 | 8874 | -- here because it will cause recursion into the whole MINIMIZED/ |
8875 | -- ELIMINATED overflow processing which is not what we want. Here | |
f32c377d | 8876 | -- we are at the top level, and we need a check against the result |
39a0c1d3 | 8877 | -- mode (i.e. we want to use STRICT mode). So do exactly that. |
4fb5f0a0 | 8878 | -- Also, we have not modified the node, so this is a case where |
8879 | -- we need to reexpand, but not reanalyze. | |
f32c377d | 8880 | |
0df9d43f | 8881 | Reexpand; |
f32c377d | 8882 | return; |
8883 | ||
8884 | -- Cases where we do the operation in Bignum mode. This happens either | |
3cce7f32 | 8885 | -- because one of our operands is in Bignum mode already, or because |
de922300 | 8886 | -- the computed bounds are outside the bounds of Long_Long_Integer, |
8887 | -- which in some cases can be indicated by Hi and Lo being No_Uint. | |
3cce7f32 | 8888 | |
8889 | -- Note: we could do better here and in some cases switch back from | |
8890 | -- Bignum mode to normal mode, e.g. big mod 2 must be in the range | |
8891 | -- 0 .. 1, but the cases are rare and it is not worth the effort. | |
8892 | -- Failing to do this switching back is only an efficiency issue. | |
8893 | ||
f32c377d | 8894 | elsif Lo = No_Uint or else Lo < LLLo or else Hi > LLHi then |
3cce7f32 | 8895 | |
61016a7a | 8896 | -- OK, we are definitely outside the range of Long_Long_Integer. The |
f32c377d | 8897 | -- question is whether to move to Bignum mode, or stay in the domain |
61016a7a | 8898 | -- of Long_Long_Integer, signalling that an overflow check is needed. |
8899 | ||
8900 | -- Obviously in MINIMIZED mode we stay with LLI, since we are not in | |
8901 | -- the Bignum business. In ELIMINATED mode, we will normally move | |
8902 | -- into Bignum mode, but there is an exception if neither of our | |
8903 | -- operands is Bignum now, and we are at the top level (Top_Level | |
8904 | -- set True). In this case, there is no point in moving into Bignum | |
8905 | -- mode to prevent overflow if the caller will immediately convert | |
8906 | -- the Bignum value back to LLI with an overflow check. It's more | |
0df9d43f | 8907 | -- efficient to stay in LLI mode with an overflow check (if needed) |
61016a7a | 8908 | |
8909 | if Check_Mode = Minimized | |
8910 | or else (Top_Level and not Bignum_Operands) | |
8911 | then | |
0df9d43f | 8912 | if Do_Overflow_Check (N) then |
8913 | Enable_Overflow_Check (N); | |
8914 | end if; | |
3cce7f32 | 8915 | |
0df9d43f | 8916 | -- The result now has to be in Long_Long_Integer mode, so adjust |
8917 | -- the possible range to reflect this. Note these calls also | |
8918 | -- change No_Uint values from the top level case to LLI bounds. | |
61016a7a | 8919 | |
8920 | Max (Lo, LLLo); | |
8921 | Min (Hi, LLHi); | |
8922 | ||
8923 | -- Otherwise we are in ELIMINATED mode and we switch to Bignum mode | |
3cce7f32 | 8924 | |
8925 | else | |
8926 | pragma Assert (Check_Mode = Eliminated); | |
8927 | ||
8928 | declare | |
8929 | Fent : Entity_Id; | |
8930 | Args : List_Id; | |
8931 | ||
8932 | begin | |
8933 | case Nkind (N) is | |
99378362 | 8934 | when N_Op_Abs => |
3cce7f32 | 8935 | Fent := RTE (RE_Big_Abs); |
8936 | ||
99378362 | 8937 | when N_Op_Add => |
3cce7f32 | 8938 | Fent := RTE (RE_Big_Add); |
8939 | ||
99378362 | 8940 | when N_Op_Divide => |
3cce7f32 | 8941 | Fent := RTE (RE_Big_Div); |
8942 | ||
99378362 | 8943 | when N_Op_Expon => |
3cce7f32 | 8944 | Fent := RTE (RE_Big_Exp); |
8945 | ||
99378362 | 8946 | when N_Op_Minus => |
3cce7f32 | 8947 | Fent := RTE (RE_Big_Neg); |
8948 | ||
99378362 | 8949 | when N_Op_Mod => |
3cce7f32 | 8950 | Fent := RTE (RE_Big_Mod); |
8951 | ||
8952 | when N_Op_Multiply => | |
8953 | Fent := RTE (RE_Big_Mul); | |
8954 | ||
99378362 | 8955 | when N_Op_Rem => |
3cce7f32 | 8956 | Fent := RTE (RE_Big_Rem); |
8957 | ||
8958 | when N_Op_Subtract => | |
8959 | Fent := RTE (RE_Big_Sub); | |
8960 | ||
8961 | -- Anything else is an internal error, this includes the | |
8962 | -- N_Op_Plus case, since how can plus cause the result | |
8963 | -- to be out of range if the operand is in range? | |
8964 | ||
8965 | when others => | |
8966 | raise Program_Error; | |
8967 | end case; | |
8968 | ||
8969 | -- Construct argument list for Bignum call, converting our | |
8970 | -- operands to Bignum form if they are not already there. | |
8971 | ||
8972 | Args := New_List; | |
8973 | ||
8974 | if Binary then | |
8975 | Append_To (Args, Convert_To_Bignum (Left_Opnd (N))); | |
8976 | end if; | |
8977 | ||
8978 | Append_To (Args, Convert_To_Bignum (Right_Opnd (N))); | |
8979 | ||
8980 | -- Now rewrite the arithmetic operator with a call to the | |
8981 | -- corresponding bignum function. | |
8982 | ||
8983 | Rewrite (N, | |
8984 | Make_Function_Call (Loc, | |
8985 | Name => New_Occurrence_Of (Fent, Loc), | |
8986 | Parameter_Associations => Args)); | |
0df9d43f | 8987 | Reanalyze (RTE (RE_Bignum), Suppress => True); |
61016a7a | 8988 | |
8989 | -- Indicate result is Bignum mode | |
8990 | ||
8991 | Lo := No_Uint; | |
8992 | Hi := No_Uint; | |
de922300 | 8993 | return; |
3cce7f32 | 8994 | end; |
8995 | end if; | |
8996 | ||
8997 | -- Otherwise we are in range of Long_Long_Integer, so no overflow | |
de922300 | 8998 | -- check is required, at least not yet. |
3cce7f32 | 8999 | |
9000 | else | |
de922300 | 9001 | Set_Do_Overflow_Check (N, False); |
9002 | end if; | |
3cce7f32 | 9003 | |
f32c377d | 9004 | -- Here we are not in Bignum territory, but we may have long long |
9005 | -- integer operands that need special handling. First a special check: | |
9006 | -- If an exponentiation operator exponent is of type Long_Long_Integer, | |
9007 | -- it means we converted it to prevent overflow, but exponentiation | |
9008 | -- requires a Natural right operand, so convert it back to Natural. | |
9009 | -- This conversion may raise an exception which is fine. | |
0326b4d4 | 9010 | |
f32c377d | 9011 | if Nkind (N) = N_Op_Expon and then Etype (Right_Opnd (N)) = LLIB then |
9012 | Convert_To_And_Rewrite (Standard_Natural, Right_Opnd (N)); | |
0326b4d4 | 9013 | end if; |
9014 | ||
de922300 | 9015 | -- Here we will do the operation in Long_Long_Integer. We do this even |
9016 | -- if we know an overflow check is required, better to do this in long | |
39a0c1d3 | 9017 | -- long integer mode, since we are less likely to overflow. |
3cce7f32 | 9018 | |
de922300 | 9019 | -- Convert right or only operand to Long_Long_Integer, except that |
9020 | -- we do not touch the exponentiation right operand. | |
3cce7f32 | 9021 | |
de922300 | 9022 | if Nkind (N) /= N_Op_Expon then |
9023 | Convert_To_And_Rewrite (LLIB, Right_Opnd (N)); | |
9024 | end if; | |
3cce7f32 | 9025 | |
de922300 | 9026 | -- Convert left operand to Long_Long_Integer for binary case |
49b3a812 | 9027 | |
de922300 | 9028 | if Binary then |
9029 | Convert_To_And_Rewrite (LLIB, Left_Opnd (N)); | |
9030 | end if; | |
9031 | ||
9032 | -- Reset node to unanalyzed | |
9033 | ||
9034 | Set_Analyzed (N, False); | |
9035 | Set_Etype (N, Empty); | |
9036 | Set_Entity (N, Empty); | |
9037 | ||
2fe22c69 | 9038 | -- Now analyze this new node. This reanalysis will complete processing |
9039 | -- for the node. In particular we will complete the expansion of an | |
9040 | -- exponentiation operator (e.g. changing A ** 2 to A * A), and also | |
9041 | -- we will complete any division checks (since we have not changed the | |
9042 | -- setting of the Do_Division_Check flag). | |
3cce7f32 | 9043 | |
0df9d43f | 9044 | -- We do this reanalysis in STRICT mode to avoid recursion into the |
39a0c1d3 | 9045 | -- MINIMIZED/ELIMINATED handling, since we are now done with that. |
3cce7f32 | 9046 | |
0df9d43f | 9047 | declare |
db415383 | 9048 | SG : constant Overflow_Mode_Type := |
9049 | Scope_Suppress.Overflow_Mode_General; | |
9050 | SA : constant Overflow_Mode_Type := | |
9051 | Scope_Suppress.Overflow_Mode_Assertions; | |
de922300 | 9052 | |
0df9d43f | 9053 | begin |
db415383 | 9054 | Scope_Suppress.Overflow_Mode_General := Strict; |
9055 | Scope_Suppress.Overflow_Mode_Assertions := Strict; | |
de922300 | 9056 | |
0df9d43f | 9057 | if not Do_Overflow_Check (N) then |
9058 | Reanalyze (LLIB, Suppress => True); | |
9059 | else | |
9060 | Reanalyze (LLIB); | |
9061 | end if; | |
9062 | ||
db415383 | 9063 | Scope_Suppress.Overflow_Mode_General := SG; |
9064 | Scope_Suppress.Overflow_Mode_Assertions := SA; | |
0df9d43f | 9065 | end; |
9066 | end Minimize_Eliminate_Overflows; | |
3cce7f32 | 9067 | |
9068 | ------------------------- | |
9069 | -- Overflow_Check_Mode -- | |
9070 | ------------------------- | |
9071 | ||
db415383 | 9072 | function Overflow_Check_Mode return Overflow_Mode_Type is |
ee6ba406 | 9073 | begin |
724d2bd8 | 9074 | if In_Assertion_Expr = 0 then |
db415383 | 9075 | return Scope_Suppress.Overflow_Mode_General; |
9dfe12ae | 9076 | else |
db415383 | 9077 | return Scope_Suppress.Overflow_Mode_Assertions; |
9dfe12ae | 9078 | end if; |
3cce7f32 | 9079 | end Overflow_Check_Mode; |
9080 | ||
9081 | -------------------------------- | |
9082 | -- Overflow_Checks_Suppressed -- | |
9083 | -------------------------------- | |
9084 | ||
9085 | function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is | |
9086 | begin | |
0df9d43f | 9087 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
9088 | return Is_Check_Suppressed (E, Overflow_Check); | |
9089 | else | |
9090 | return Scope_Suppress.Suppress (Overflow_Check); | |
9091 | end if; | |
ee6ba406 | 9092 | end Overflow_Checks_Suppressed; |
fc75802a | 9093 | |
37baba83 | 9094 | --------------------------------- |
9095 | -- Predicate_Checks_Suppressed -- | |
9096 | --------------------------------- | |
9097 | ||
9098 | function Predicate_Checks_Suppressed (E : Entity_Id) return Boolean is | |
9099 | begin | |
9100 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
9101 | return Is_Check_Suppressed (E, Predicate_Check); | |
9102 | else | |
9103 | return Scope_Suppress.Suppress (Predicate_Check); | |
9104 | end if; | |
9105 | end Predicate_Checks_Suppressed; | |
9106 | ||
ee6ba406 | 9107 | ----------------------------- |
9108 | -- Range_Checks_Suppressed -- | |
9109 | ----------------------------- | |
9110 | ||
9111 | function Range_Checks_Suppressed (E : Entity_Id) return Boolean is | |
9112 | begin | |
9dfe12ae | 9113 | if Present (E) then |
ce4d14c4 | 9114 | if Kill_Range_Checks (E) then |
9dfe12ae | 9115 | return True; |
5f46de53 | 9116 | |
9dfe12ae | 9117 | elsif Checks_May_Be_Suppressed (E) then |
9118 | return Is_Check_Suppressed (E, Range_Check); | |
9119 | end if; | |
9120 | end if; | |
ee6ba406 | 9121 | |
fafc6b97 | 9122 | return Scope_Suppress.Suppress (Range_Check); |
ee6ba406 | 9123 | end Range_Checks_Suppressed; |
9124 | ||
0577b0b1 | 9125 | ----------------------------------------- |
9126 | -- Range_Or_Validity_Checks_Suppressed -- | |
9127 | ----------------------------------------- | |
9128 | ||
9129 | -- Note: the coding would be simpler here if we simply made appropriate | |
9130 | -- calls to Range/Validity_Checks_Suppressed, but that would result in | |
9131 | -- duplicated checks which we prefer to avoid. | |
9132 | ||
9133 | function Range_Or_Validity_Checks_Suppressed | |
9134 | (Expr : Node_Id) return Boolean | |
9135 | is | |
9136 | begin | |
9137 | -- Immediate return if scope checks suppressed for either check | |
9138 | ||
fafc6b97 | 9139 | if Scope_Suppress.Suppress (Range_Check) |
9140 | or | |
9141 | Scope_Suppress.Suppress (Validity_Check) | |
9142 | then | |
0577b0b1 | 9143 | return True; |
9144 | end if; | |
9145 | ||
9146 | -- If no expression, that's odd, decide that checks are suppressed, | |
9147 | -- since we don't want anyone trying to do checks in this case, which | |
9148 | -- is most likely the result of some other error. | |
9149 | ||
9150 | if No (Expr) then | |
9151 | return True; | |
9152 | end if; | |
9153 | ||
9154 | -- Expression is present, so perform suppress checks on type | |
9155 | ||
9156 | declare | |
9157 | Typ : constant Entity_Id := Etype (Expr); | |
9158 | begin | |
ce4d14c4 | 9159 | if Checks_May_Be_Suppressed (Typ) |
0577b0b1 | 9160 | and then (Is_Check_Suppressed (Typ, Range_Check) |
9161 | or else | |
9162 | Is_Check_Suppressed (Typ, Validity_Check)) | |
9163 | then | |
9164 | return True; | |
9165 | end if; | |
9166 | end; | |
9167 | ||
9168 | -- If expression is an entity name, perform checks on this entity | |
9169 | ||
9170 | if Is_Entity_Name (Expr) then | |
9171 | declare | |
9172 | Ent : constant Entity_Id := Entity (Expr); | |
9173 | begin | |
9174 | if Checks_May_Be_Suppressed (Ent) then | |
9175 | return Is_Check_Suppressed (Ent, Range_Check) | |
9176 | or else Is_Check_Suppressed (Ent, Validity_Check); | |
9177 | end if; | |
9178 | end; | |
9179 | end if; | |
9180 | ||
9181 | -- If we fall through, no checks suppressed | |
9182 | ||
9183 | return False; | |
9184 | end Range_Or_Validity_Checks_Suppressed; | |
9185 | ||
226494a3 | 9186 | ------------------- |
9187 | -- Remove_Checks -- | |
9188 | ------------------- | |
9189 | ||
9190 | procedure Remove_Checks (Expr : Node_Id) is | |
226494a3 | 9191 | function Process (N : Node_Id) return Traverse_Result; |
9192 | -- Process a single node during the traversal | |
9193 | ||
8f6e4fd5 | 9194 | procedure Traverse is new Traverse_Proc (Process); |
9195 | -- The traversal procedure itself | |
226494a3 | 9196 | |
9197 | ------------- | |
9198 | -- Process -- | |
9199 | ------------- | |
9200 | ||
9201 | function Process (N : Node_Id) return Traverse_Result is | |
9202 | begin | |
9203 | if Nkind (N) not in N_Subexpr then | |
9204 | return Skip; | |
9205 | end if; | |
9206 | ||
9207 | Set_Do_Range_Check (N, False); | |
9208 | ||
9209 | case Nkind (N) is | |
9210 | when N_And_Then => | |
8f6e4fd5 | 9211 | Traverse (Left_Opnd (N)); |
226494a3 | 9212 | return Skip; |
9213 | ||
9214 | when N_Attribute_Reference => | |
226494a3 | 9215 | Set_Do_Overflow_Check (N, False); |
9216 | ||
226494a3 | 9217 | when N_Function_Call => |
9218 | Set_Do_Tag_Check (N, False); | |
9219 | ||
226494a3 | 9220 | when N_Op => |
9221 | Set_Do_Overflow_Check (N, False); | |
9222 | ||
9223 | case Nkind (N) is | |
9224 | when N_Op_Divide => | |
9225 | Set_Do_Division_Check (N, False); | |
9226 | ||
9227 | when N_Op_And => | |
9228 | Set_Do_Length_Check (N, False); | |
9229 | ||
9230 | when N_Op_Mod => | |
9231 | Set_Do_Division_Check (N, False); | |
9232 | ||
9233 | when N_Op_Or => | |
9234 | Set_Do_Length_Check (N, False); | |
9235 | ||
9236 | when N_Op_Rem => | |
9237 | Set_Do_Division_Check (N, False); | |
9238 | ||
9239 | when N_Op_Xor => | |
9240 | Set_Do_Length_Check (N, False); | |
9241 | ||
9242 | when others => | |
9243 | null; | |
9244 | end case; | |
9245 | ||
9246 | when N_Or_Else => | |
8f6e4fd5 | 9247 | Traverse (Left_Opnd (N)); |
226494a3 | 9248 | return Skip; |
9249 | ||
9250 | when N_Selected_Component => | |
226494a3 | 9251 | Set_Do_Discriminant_Check (N, False); |
9252 | ||
226494a3 | 9253 | when N_Type_Conversion => |
9dfe12ae | 9254 | Set_Do_Length_Check (N, False); |
9255 | Set_Do_Tag_Check (N, False); | |
226494a3 | 9256 | Set_Do_Overflow_Check (N, False); |
226494a3 | 9257 | |
9258 | when others => | |
9259 | null; | |
9260 | end case; | |
9261 | ||
9262 | return OK; | |
9263 | end Process; | |
9264 | ||
9265 | -- Start of processing for Remove_Checks | |
9266 | ||
9267 | begin | |
8f6e4fd5 | 9268 | Traverse (Expr); |
226494a3 | 9269 | end Remove_Checks; |
9270 | ||
ee6ba406 | 9271 | ---------------------------- |
9272 | -- Selected_Length_Checks -- | |
9273 | ---------------------------- | |
9274 | ||
9275 | function Selected_Length_Checks | |
9276 | (Ck_Node : Node_Id; | |
9277 | Target_Typ : Entity_Id; | |
9278 | Source_Typ : Entity_Id; | |
314a23b6 | 9279 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 9280 | is |
9281 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
9282 | S_Typ : Entity_Id; | |
9283 | T_Typ : Entity_Id; | |
9284 | Expr_Actual : Node_Id; | |
9285 | Exptyp : Entity_Id; | |
9286 | Cond : Node_Id := Empty; | |
9287 | Do_Access : Boolean := False; | |
9288 | Wnode : Node_Id := Warn_Node; | |
9289 | Ret_Result : Check_Result := (Empty, Empty); | |
9290 | Num_Checks : Natural := 0; | |
9291 | ||
9292 | procedure Add_Check (N : Node_Id); | |
9293 | -- Adds the action given to Ret_Result if N is non-Empty | |
9294 | ||
9295 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id; | |
9296 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id; | |
314a23b6 | 9297 | -- Comments required ??? |
ee6ba406 | 9298 | |
9299 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean; | |
9300 | -- True for equal literals and for nodes that denote the same constant | |
5f260d20 | 9301 | -- entity, even if its value is not a static constant. This includes the |
9dfe12ae | 9302 | -- case of a discriminal reference within an init proc. Removes some |
5f260d20 | 9303 | -- obviously superfluous checks. |
ee6ba406 | 9304 | |
9305 | function Length_E_Cond | |
9306 | (Exptyp : Entity_Id; | |
9307 | Typ : Entity_Id; | |
314a23b6 | 9308 | Indx : Nat) return Node_Id; |
ee6ba406 | 9309 | -- Returns expression to compute: |
9310 | -- Typ'Length /= Exptyp'Length | |
9311 | ||
9312 | function Length_N_Cond | |
9313 | (Expr : Node_Id; | |
9314 | Typ : Entity_Id; | |
314a23b6 | 9315 | Indx : Nat) return Node_Id; |
ee6ba406 | 9316 | -- Returns expression to compute: |
9317 | -- Typ'Length /= Expr'Length | |
9318 | ||
9319 | --------------- | |
9320 | -- Add_Check -- | |
9321 | --------------- | |
9322 | ||
9323 | procedure Add_Check (N : Node_Id) is | |
9324 | begin | |
9325 | if Present (N) then | |
9326 | ||
20cf157b | 9327 | -- For now, ignore attempt to place more than two checks ??? |
9328 | -- This is really worrisome, are we really discarding checks ??? | |
ee6ba406 | 9329 | |
9330 | if Num_Checks = 2 then | |
9331 | return; | |
9332 | end if; | |
9333 | ||
9334 | pragma Assert (Num_Checks <= 1); | |
9335 | Num_Checks := Num_Checks + 1; | |
9336 | Ret_Result (Num_Checks) := N; | |
9337 | end if; | |
9338 | end Add_Check; | |
9339 | ||
9340 | ------------------ | |
9341 | -- Get_E_Length -- | |
9342 | ------------------ | |
9343 | ||
9344 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is | |
00c403ee | 9345 | SE : constant Entity_Id := Scope (E); |
ee6ba406 | 9346 | N : Node_Id; |
9347 | E1 : Entity_Id := E; | |
ee6ba406 | 9348 | |
9349 | begin | |
9350 | if Ekind (Scope (E)) = E_Record_Type | |
9351 | and then Has_Discriminants (Scope (E)) | |
9352 | then | |
9353 | N := Build_Discriminal_Subtype_Of_Component (E); | |
9354 | ||
9355 | if Present (N) then | |
9356 | Insert_Action (Ck_Node, N); | |
9357 | E1 := Defining_Identifier (N); | |
9358 | end if; | |
9359 | end if; | |
9360 | ||
9361 | if Ekind (E1) = E_String_Literal_Subtype then | |
9362 | return | |
9363 | Make_Integer_Literal (Loc, | |
9364 | Intval => String_Literal_Length (E1)); | |
9365 | ||
00c403ee | 9366 | elsif SE /= Standard_Standard |
9367 | and then Ekind (Scope (SE)) = E_Protected_Type | |
9368 | and then Has_Discriminants (Scope (SE)) | |
9369 | and then Has_Completion (Scope (SE)) | |
ee6ba406 | 9370 | and then not Inside_Init_Proc |
9371 | then | |
ee6ba406 | 9372 | -- If the type whose length is needed is a private component |
9373 | -- constrained by a discriminant, we must expand the 'Length | |
9374 | -- attribute into an explicit computation, using the discriminal | |
9375 | -- of the current protected operation. This is because the actual | |
9376 | -- type of the prival is constructed after the protected opera- | |
9377 | -- tion has been fully expanded. | |
9378 | ||
9379 | declare | |
9380 | Indx_Type : Node_Id; | |
9381 | Lo : Node_Id; | |
9382 | Hi : Node_Id; | |
9383 | Do_Expand : Boolean := False; | |
9384 | ||
9385 | begin | |
9386 | Indx_Type := First_Index (E); | |
9387 | ||
9388 | for J in 1 .. Indx - 1 loop | |
9389 | Next_Index (Indx_Type); | |
9390 | end loop; | |
9391 | ||
2af58f67 | 9392 | Get_Index_Bounds (Indx_Type, Lo, Hi); |
ee6ba406 | 9393 | |
9394 | if Nkind (Lo) = N_Identifier | |
9395 | and then Ekind (Entity (Lo)) = E_In_Parameter | |
9396 | then | |
9397 | Lo := Get_Discriminal (E, Lo); | |
9398 | Do_Expand := True; | |
9399 | end if; | |
9400 | ||
9401 | if Nkind (Hi) = N_Identifier | |
9402 | and then Ekind (Entity (Hi)) = E_In_Parameter | |
9403 | then | |
9404 | Hi := Get_Discriminal (E, Hi); | |
9405 | Do_Expand := True; | |
9406 | end if; | |
9407 | ||
9408 | if Do_Expand then | |
9409 | if not Is_Entity_Name (Lo) then | |
9dfe12ae | 9410 | Lo := Duplicate_Subexpr_No_Checks (Lo); |
ee6ba406 | 9411 | end if; |
9412 | ||
9413 | if not Is_Entity_Name (Hi) then | |
9dfe12ae | 9414 | Lo := Duplicate_Subexpr_No_Checks (Hi); |
ee6ba406 | 9415 | end if; |
9416 | ||
9417 | N := | |
9418 | Make_Op_Add (Loc, | |
9419 | Left_Opnd => | |
9420 | Make_Op_Subtract (Loc, | |
9421 | Left_Opnd => Hi, | |
9422 | Right_Opnd => Lo), | |
9423 | ||
9424 | Right_Opnd => Make_Integer_Literal (Loc, 1)); | |
9425 | return N; | |
9426 | ||
9427 | else | |
9428 | N := | |
9429 | Make_Attribute_Reference (Loc, | |
9430 | Attribute_Name => Name_Length, | |
9431 | Prefix => | |
9432 | New_Occurrence_Of (E1, Loc)); | |
9433 | ||
9434 | if Indx > 1 then | |
9435 | Set_Expressions (N, New_List ( | |
9436 | Make_Integer_Literal (Loc, Indx))); | |
9437 | end if; | |
9438 | ||
9439 | return N; | |
9440 | end if; | |
9441 | end; | |
9442 | ||
9443 | else | |
9444 | N := | |
9445 | Make_Attribute_Reference (Loc, | |
9446 | Attribute_Name => Name_Length, | |
9447 | Prefix => | |
9448 | New_Occurrence_Of (E1, Loc)); | |
9449 | ||
9450 | if Indx > 1 then | |
9451 | Set_Expressions (N, New_List ( | |
9452 | Make_Integer_Literal (Loc, Indx))); | |
9453 | end if; | |
9454 | ||
9455 | return N; | |
ee6ba406 | 9456 | end if; |
9457 | end Get_E_Length; | |
9458 | ||
9459 | ------------------ | |
9460 | -- Get_N_Length -- | |
9461 | ------------------ | |
9462 | ||
9463 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is | |
9464 | begin | |
9465 | return | |
9466 | Make_Attribute_Reference (Loc, | |
9467 | Attribute_Name => Name_Length, | |
9468 | Prefix => | |
9dfe12ae | 9469 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 9470 | Expressions => New_List ( |
9471 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 9472 | end Get_N_Length; |
9473 | ||
9474 | ------------------- | |
9475 | -- Length_E_Cond -- | |
9476 | ------------------- | |
9477 | ||
9478 | function Length_E_Cond | |
9479 | (Exptyp : Entity_Id; | |
9480 | Typ : Entity_Id; | |
314a23b6 | 9481 | Indx : Nat) return Node_Id |
ee6ba406 | 9482 | is |
9483 | begin | |
9484 | return | |
9485 | Make_Op_Ne (Loc, | |
9486 | Left_Opnd => Get_E_Length (Typ, Indx), | |
9487 | Right_Opnd => Get_E_Length (Exptyp, Indx)); | |
ee6ba406 | 9488 | end Length_E_Cond; |
9489 | ||
9490 | ------------------- | |
9491 | -- Length_N_Cond -- | |
9492 | ------------------- | |
9493 | ||
9494 | function Length_N_Cond | |
9495 | (Expr : Node_Id; | |
9496 | Typ : Entity_Id; | |
314a23b6 | 9497 | Indx : Nat) return Node_Id |
ee6ba406 | 9498 | is |
9499 | begin | |
9500 | return | |
9501 | Make_Op_Ne (Loc, | |
9502 | Left_Opnd => Get_E_Length (Typ, Indx), | |
9503 | Right_Opnd => Get_N_Length (Expr, Indx)); | |
ee6ba406 | 9504 | end Length_N_Cond; |
9505 | ||
feff2f05 | 9506 | ----------------- |
9507 | -- Same_Bounds -- | |
9508 | ----------------- | |
9509 | ||
ee6ba406 | 9510 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is |
9511 | begin | |
9512 | return | |
9513 | (Nkind (L) = N_Integer_Literal | |
9514 | and then Nkind (R) = N_Integer_Literal | |
9515 | and then Intval (L) = Intval (R)) | |
9516 | ||
9517 | or else | |
9518 | (Is_Entity_Name (L) | |
9519 | and then Ekind (Entity (L)) = E_Constant | |
9520 | and then ((Is_Entity_Name (R) | |
9521 | and then Entity (L) = Entity (R)) | |
9522 | or else | |
9523 | (Nkind (R) = N_Type_Conversion | |
9524 | and then Is_Entity_Name (Expression (R)) | |
9525 | and then Entity (L) = Entity (Expression (R))))) | |
9526 | ||
9527 | or else | |
9528 | (Is_Entity_Name (R) | |
9529 | and then Ekind (Entity (R)) = E_Constant | |
9530 | and then Nkind (L) = N_Type_Conversion | |
9531 | and then Is_Entity_Name (Expression (L)) | |
5f260d20 | 9532 | and then Entity (R) = Entity (Expression (L))) |
9533 | ||
9534 | or else | |
9535 | (Is_Entity_Name (L) | |
9536 | and then Is_Entity_Name (R) | |
9537 | and then Entity (L) = Entity (R) | |
9538 | and then Ekind (Entity (L)) = E_In_Parameter | |
9539 | and then Inside_Init_Proc); | |
ee6ba406 | 9540 | end Same_Bounds; |
9541 | ||
9542 | -- Start of processing for Selected_Length_Checks | |
9543 | ||
9544 | begin | |
18cb6d78 | 9545 | -- Checks will be applied only when generating code |
f0d65dae | 9546 | |
18cb6d78 | 9547 | if not Expander_Active then |
ee6ba406 | 9548 | return Ret_Result; |
9549 | end if; | |
9550 | ||
9551 | if Target_Typ = Any_Type | |
9552 | or else Target_Typ = Any_Composite | |
9553 | or else Raises_Constraint_Error (Ck_Node) | |
9554 | then | |
9555 | return Ret_Result; | |
9556 | end if; | |
9557 | ||
9558 | if No (Wnode) then | |
9559 | Wnode := Ck_Node; | |
9560 | end if; | |
9561 | ||
9562 | T_Typ := Target_Typ; | |
9563 | ||
9564 | if No (Source_Typ) then | |
9565 | S_Typ := Etype (Ck_Node); | |
9566 | else | |
9567 | S_Typ := Source_Typ; | |
9568 | end if; | |
9569 | ||
9570 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
9571 | return Ret_Result; | |
9572 | end if; | |
9573 | ||
9574 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
9575 | S_Typ := Designated_Type (S_Typ); | |
9576 | T_Typ := Designated_Type (T_Typ); | |
9577 | Do_Access := True; | |
9578 | ||
2af58f67 | 9579 | -- A simple optimization for the null case |
ee6ba406 | 9580 | |
2af58f67 | 9581 | if Known_Null (Ck_Node) then |
ee6ba406 | 9582 | return Ret_Result; |
9583 | end if; | |
9584 | end if; | |
9585 | ||
9586 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
9587 | if Is_Constrained (T_Typ) then | |
9588 | ||
92f1631f | 9589 | -- The checking code to be generated will freeze the corresponding |
9590 | -- array type. However, we must freeze the type now, so that the | |
9591 | -- freeze node does not appear within the generated if expression, | |
9592 | -- but ahead of it. | |
ee6ba406 | 9593 | |
9594 | Freeze_Before (Ck_Node, T_Typ); | |
9595 | ||
9596 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
84d0d4a5 | 9597 | Exptyp := Get_Actual_Subtype (Ck_Node); |
ee6ba406 | 9598 | |
9599 | if Is_Access_Type (Exptyp) then | |
9600 | Exptyp := Designated_Type (Exptyp); | |
9601 | end if; | |
9602 | ||
9603 | -- String_Literal case. This needs to be handled specially be- | |
9604 | -- cause no index types are available for string literals. The | |
9605 | -- condition is simply: | |
9606 | ||
9607 | -- T_Typ'Length = string-literal-length | |
9608 | ||
9dfe12ae | 9609 | if Nkind (Expr_Actual) = N_String_Literal |
9610 | and then Ekind (Etype (Expr_Actual)) = E_String_Literal_Subtype | |
9611 | then | |
ee6ba406 | 9612 | Cond := |
9613 | Make_Op_Ne (Loc, | |
9614 | Left_Opnd => Get_E_Length (T_Typ, 1), | |
9615 | Right_Opnd => | |
9616 | Make_Integer_Literal (Loc, | |
9617 | Intval => | |
9618 | String_Literal_Length (Etype (Expr_Actual)))); | |
9619 | ||
9620 | -- General array case. Here we have a usable actual subtype for | |
9621 | -- the expression, and the condition is built from the two types | |
9622 | -- (Do_Length): | |
9623 | ||
9624 | -- T_Typ'Length /= Exptyp'Length or else | |
9625 | -- T_Typ'Length (2) /= Exptyp'Length (2) or else | |
9626 | -- T_Typ'Length (3) /= Exptyp'Length (3) or else | |
9627 | -- ... | |
9628 | ||
9629 | elsif Is_Constrained (Exptyp) then | |
9630 | declare | |
9dfe12ae | 9631 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
9632 | ||
9633 | L_Index : Node_Id; | |
9634 | R_Index : Node_Id; | |
9635 | L_Low : Node_Id; | |
9636 | L_High : Node_Id; | |
9637 | R_Low : Node_Id; | |
9638 | R_High : Node_Id; | |
ee6ba406 | 9639 | L_Length : Uint; |
9640 | R_Length : Uint; | |
9dfe12ae | 9641 | Ref_Node : Node_Id; |
ee6ba406 | 9642 | |
9643 | begin | |
feff2f05 | 9644 | -- At the library level, we need to ensure that the type of |
9645 | -- the object is elaborated before the check itself is | |
9646 | -- emitted. This is only done if the object is in the | |
9647 | -- current compilation unit, otherwise the type is frozen | |
9648 | -- and elaborated in its unit. | |
9dfe12ae | 9649 | |
9650 | if Is_Itype (Exptyp) | |
9651 | and then | |
9652 | Ekind (Cunit_Entity (Current_Sem_Unit)) = E_Package | |
9653 | and then | |
9654 | not In_Package_Body (Cunit_Entity (Current_Sem_Unit)) | |
d66aa9f6 | 9655 | and then In_Open_Scopes (Scope (Exptyp)) |
9dfe12ae | 9656 | then |
9657 | Ref_Node := Make_Itype_Reference (Sloc (Ck_Node)); | |
9658 | Set_Itype (Ref_Node, Exptyp); | |
9659 | Insert_Action (Ck_Node, Ref_Node); | |
9660 | end if; | |
9661 | ||
ee6ba406 | 9662 | L_Index := First_Index (T_Typ); |
9663 | R_Index := First_Index (Exptyp); | |
9664 | ||
9665 | for Indx in 1 .. Ndims loop | |
9666 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 9667 | or else |
9668 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 9669 | then |
9670 | Get_Index_Bounds (L_Index, L_Low, L_High); | |
9671 | Get_Index_Bounds (R_Index, R_Low, R_High); | |
9672 | ||
9673 | -- Deal with compile time length check. Note that we | |
9674 | -- skip this in the access case, because the access | |
9675 | -- value may be null, so we cannot know statically. | |
9676 | ||
9677 | if not Do_Access | |
9678 | and then Compile_Time_Known_Value (L_Low) | |
9679 | and then Compile_Time_Known_Value (L_High) | |
9680 | and then Compile_Time_Known_Value (R_Low) | |
9681 | and then Compile_Time_Known_Value (R_High) | |
9682 | then | |
9683 | if Expr_Value (L_High) >= Expr_Value (L_Low) then | |
9684 | L_Length := Expr_Value (L_High) - | |
9685 | Expr_Value (L_Low) + 1; | |
9686 | else | |
9687 | L_Length := UI_From_Int (0); | |
9688 | end if; | |
9689 | ||
9690 | if Expr_Value (R_High) >= Expr_Value (R_Low) then | |
9691 | R_Length := Expr_Value (R_High) - | |
9692 | Expr_Value (R_Low) + 1; | |
9693 | else | |
9694 | R_Length := UI_From_Int (0); | |
9695 | end if; | |
9696 | ||
9697 | if L_Length > R_Length then | |
9698 | Add_Check | |
9699 | (Compile_Time_Constraint_Error | |
cb97ae5c | 9700 | (Wnode, "too few elements for}??", T_Typ)); |
ee6ba406 | 9701 | |
b8eacb12 | 9702 | elsif L_Length < R_Length then |
ee6ba406 | 9703 | Add_Check |
9704 | (Compile_Time_Constraint_Error | |
cb97ae5c | 9705 | (Wnode, "too many elements for}??", T_Typ)); |
ee6ba406 | 9706 | end if; |
9707 | ||
9708 | -- The comparison for an individual index subtype | |
9709 | -- is omitted if the corresponding index subtypes | |
9710 | -- statically match, since the result is known to | |
9711 | -- be true. Note that this test is worth while even | |
9712 | -- though we do static evaluation, because non-static | |
9713 | -- subtypes can statically match. | |
9714 | ||
9715 | elsif not | |
9716 | Subtypes_Statically_Match | |
9717 | (Etype (L_Index), Etype (R_Index)) | |
9718 | ||
9719 | and then not | |
9720 | (Same_Bounds (L_Low, R_Low) | |
9721 | and then Same_Bounds (L_High, R_High)) | |
9722 | then | |
9723 | Evolve_Or_Else | |
9724 | (Cond, Length_E_Cond (Exptyp, T_Typ, Indx)); | |
9725 | end if; | |
9726 | ||
9727 | Next (L_Index); | |
9728 | Next (R_Index); | |
9729 | end if; | |
9730 | end loop; | |
9731 | end; | |
9732 | ||
9733 | -- Handle cases where we do not get a usable actual subtype that | |
9734 | -- is constrained. This happens for example in the function call | |
9735 | -- and explicit dereference cases. In these cases, we have to get | |
9736 | -- the length or range from the expression itself, making sure we | |
9737 | -- do not evaluate it more than once. | |
9738 | ||
9739 | -- Here Ck_Node is the original expression, or more properly the | |
feff2f05 | 9740 | -- result of applying Duplicate_Expr to the original tree, forcing |
9741 | -- the result to be a name. | |
ee6ba406 | 9742 | |
9743 | else | |
9744 | declare | |
9dfe12ae | 9745 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 9746 | |
9747 | begin | |
9748 | -- Build the condition for the explicit dereference case | |
9749 | ||
9750 | for Indx in 1 .. Ndims loop | |
9751 | Evolve_Or_Else | |
9752 | (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx)); | |
9753 | end loop; | |
9754 | end; | |
9755 | end if; | |
9756 | end if; | |
9757 | end if; | |
9758 | ||
9759 | -- Construct the test and insert into the tree | |
9760 | ||
9761 | if Present (Cond) then | |
9762 | if Do_Access then | |
9763 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
9764 | end if; | |
9765 | ||
f15731c4 | 9766 | Add_Check |
9767 | (Make_Raise_Constraint_Error (Loc, | |
9768 | Condition => Cond, | |
9769 | Reason => CE_Length_Check_Failed)); | |
ee6ba406 | 9770 | end if; |
9771 | ||
9772 | return Ret_Result; | |
ee6ba406 | 9773 | end Selected_Length_Checks; |
9774 | ||
9775 | --------------------------- | |
9776 | -- Selected_Range_Checks -- | |
9777 | --------------------------- | |
9778 | ||
9779 | function Selected_Range_Checks | |
9780 | (Ck_Node : Node_Id; | |
9781 | Target_Typ : Entity_Id; | |
9782 | Source_Typ : Entity_Id; | |
314a23b6 | 9783 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 9784 | is |
9785 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
9786 | S_Typ : Entity_Id; | |
9787 | T_Typ : Entity_Id; | |
9788 | Expr_Actual : Node_Id; | |
9789 | Exptyp : Entity_Id; | |
9790 | Cond : Node_Id := Empty; | |
9791 | Do_Access : Boolean := False; | |
9792 | Wnode : Node_Id := Warn_Node; | |
9793 | Ret_Result : Check_Result := (Empty, Empty); | |
9794 | Num_Checks : Integer := 0; | |
9795 | ||
9796 | procedure Add_Check (N : Node_Id); | |
9797 | -- Adds the action given to Ret_Result if N is non-Empty | |
9798 | ||
9799 | function Discrete_Range_Cond | |
9800 | (Expr : Node_Id; | |
314a23b6 | 9801 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 9802 | -- Returns expression to compute: |
9803 | -- Low_Bound (Expr) < Typ'First | |
9804 | -- or else | |
9805 | -- High_Bound (Expr) > Typ'Last | |
9806 | ||
9807 | function Discrete_Expr_Cond | |
9808 | (Expr : Node_Id; | |
314a23b6 | 9809 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 9810 | -- Returns expression to compute: |
9811 | -- Expr < Typ'First | |
9812 | -- or else | |
9813 | -- Expr > Typ'Last | |
9814 | ||
9815 | function Get_E_First_Or_Last | |
3cb12758 | 9816 | (Loc : Source_Ptr; |
9817 | E : Entity_Id; | |
ee6ba406 | 9818 | Indx : Nat; |
314a23b6 | 9819 | Nam : Name_Id) return Node_Id; |
79212397 | 9820 | -- Returns an attribute reference |
ee6ba406 | 9821 | -- E'First or E'Last |
79212397 | 9822 | -- with a source location of Loc. |
f73ee678 | 9823 | -- |
79212397 | 9824 | -- Nam is Name_First or Name_Last, according to which attribute is |
9825 | -- desired. If Indx is non-zero, it is passed as a literal in the | |
9826 | -- Expressions of the attribute reference (identifying the desired | |
9827 | -- array dimension). | |
ee6ba406 | 9828 | |
9829 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id; | |
9830 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id; | |
9831 | -- Returns expression to compute: | |
9dfe12ae | 9832 | -- N'First or N'Last using Duplicate_Subexpr_No_Checks |
ee6ba406 | 9833 | |
9834 | function Range_E_Cond | |
9835 | (Exptyp : Entity_Id; | |
9836 | Typ : Entity_Id; | |
9837 | Indx : Nat) | |
9838 | return Node_Id; | |
9839 | -- Returns expression to compute: | |
9840 | -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last | |
9841 | ||
9842 | function Range_Equal_E_Cond | |
9843 | (Exptyp : Entity_Id; | |
9844 | Typ : Entity_Id; | |
314a23b6 | 9845 | Indx : Nat) return Node_Id; |
ee6ba406 | 9846 | -- Returns expression to compute: |
9847 | -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last | |
9848 | ||
9849 | function Range_N_Cond | |
9850 | (Expr : Node_Id; | |
9851 | Typ : Entity_Id; | |
314a23b6 | 9852 | Indx : Nat) return Node_Id; |
ee6ba406 | 9853 | -- Return expression to compute: |
9854 | -- Expr'First < Typ'First or else Expr'Last > Typ'Last | |
9855 | ||
9856 | --------------- | |
9857 | -- Add_Check -- | |
9858 | --------------- | |
9859 | ||
9860 | procedure Add_Check (N : Node_Id) is | |
9861 | begin | |
9862 | if Present (N) then | |
9863 | ||
9864 | -- For now, ignore attempt to place more than 2 checks ??? | |
9865 | ||
9866 | if Num_Checks = 2 then | |
9867 | return; | |
9868 | end if; | |
9869 | ||
9870 | pragma Assert (Num_Checks <= 1); | |
9871 | Num_Checks := Num_Checks + 1; | |
9872 | Ret_Result (Num_Checks) := N; | |
9873 | end if; | |
9874 | end Add_Check; | |
9875 | ||
9876 | ------------------------- | |
9877 | -- Discrete_Expr_Cond -- | |
9878 | ------------------------- | |
9879 | ||
9880 | function Discrete_Expr_Cond | |
9881 | (Expr : Node_Id; | |
314a23b6 | 9882 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 9883 | is |
9884 | begin | |
9885 | return | |
9886 | Make_Or_Else (Loc, | |
9887 | Left_Opnd => | |
9888 | Make_Op_Lt (Loc, | |
9889 | Left_Opnd => | |
9dfe12ae | 9890 | Convert_To (Base_Type (Typ), |
9891 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 9892 | Right_Opnd => |
9893 | Convert_To (Base_Type (Typ), | |
3cb12758 | 9894 | Get_E_First_Or_Last (Loc, Typ, 0, Name_First))), |
ee6ba406 | 9895 | |
9896 | Right_Opnd => | |
9897 | Make_Op_Gt (Loc, | |
9898 | Left_Opnd => | |
9dfe12ae | 9899 | Convert_To (Base_Type (Typ), |
9900 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 9901 | Right_Opnd => |
9902 | Convert_To | |
9903 | (Base_Type (Typ), | |
3cb12758 | 9904 | Get_E_First_Or_Last (Loc, Typ, 0, Name_Last)))); |
ee6ba406 | 9905 | end Discrete_Expr_Cond; |
9906 | ||
9907 | ------------------------- | |
9908 | -- Discrete_Range_Cond -- | |
9909 | ------------------------- | |
9910 | ||
9911 | function Discrete_Range_Cond | |
9912 | (Expr : Node_Id; | |
314a23b6 | 9913 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 9914 | is |
9915 | LB : Node_Id := Low_Bound (Expr); | |
9916 | HB : Node_Id := High_Bound (Expr); | |
9917 | ||
9918 | Left_Opnd : Node_Id; | |
9919 | Right_Opnd : Node_Id; | |
9920 | ||
9921 | begin | |
9922 | if Nkind (LB) = N_Identifier | |
feff2f05 | 9923 | and then Ekind (Entity (LB)) = E_Discriminant |
9924 | then | |
ee6ba406 | 9925 | LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc); |
9926 | end if; | |
9927 | ||
ee6ba406 | 9928 | Left_Opnd := |
9929 | Make_Op_Lt (Loc, | |
9930 | Left_Opnd => | |
9931 | Convert_To | |
9dfe12ae | 9932 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (LB)), |
ee6ba406 | 9933 | |
9934 | Right_Opnd => | |
9935 | Convert_To | |
3cb12758 | 9936 | (Base_Type (Typ), |
9937 | Get_E_First_Or_Last (Loc, Typ, 0, Name_First))); | |
ee6ba406 | 9938 | |
ba9b1a39 | 9939 | if Nkind (HB) = N_Identifier |
9940 | and then Ekind (Entity (HB)) = E_Discriminant | |
ee6ba406 | 9941 | then |
ba9b1a39 | 9942 | HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc); |
ee6ba406 | 9943 | end if; |
9944 | ||
9945 | Right_Opnd := | |
9946 | Make_Op_Gt (Loc, | |
9947 | Left_Opnd => | |
9948 | Convert_To | |
9dfe12ae | 9949 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (HB)), |
ee6ba406 | 9950 | |
9951 | Right_Opnd => | |
9952 | Convert_To | |
9953 | (Base_Type (Typ), | |
3cb12758 | 9954 | Get_E_First_Or_Last (Loc, Typ, 0, Name_Last))); |
ee6ba406 | 9955 | |
9956 | return Make_Or_Else (Loc, Left_Opnd, Right_Opnd); | |
9957 | end Discrete_Range_Cond; | |
9958 | ||
9959 | ------------------------- | |
9960 | -- Get_E_First_Or_Last -- | |
9961 | ------------------------- | |
9962 | ||
9963 | function Get_E_First_Or_Last | |
3cb12758 | 9964 | (Loc : Source_Ptr; |
9965 | E : Entity_Id; | |
ee6ba406 | 9966 | Indx : Nat; |
314a23b6 | 9967 | Nam : Name_Id) return Node_Id |
ee6ba406 | 9968 | is |
3cb12758 | 9969 | Exprs : List_Id; |
ee6ba406 | 9970 | begin |
3cb12758 | 9971 | if Indx > 0 then |
9972 | Exprs := New_List (Make_Integer_Literal (Loc, UI_From_Int (Indx))); | |
ee6ba406 | 9973 | else |
3cb12758 | 9974 | Exprs := No_List; |
ee6ba406 | 9975 | end if; |
9976 | ||
3cb12758 | 9977 | return Make_Attribute_Reference (Loc, |
9978 | Prefix => New_Occurrence_Of (E, Loc), | |
9979 | Attribute_Name => Nam, | |
9980 | Expressions => Exprs); | |
ee6ba406 | 9981 | end Get_E_First_Or_Last; |
9982 | ||
9983 | ----------------- | |
9984 | -- Get_N_First -- | |
9985 | ----------------- | |
9986 | ||
9987 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is | |
9988 | begin | |
9989 | return | |
9990 | Make_Attribute_Reference (Loc, | |
9991 | Attribute_Name => Name_First, | |
9992 | Prefix => | |
9dfe12ae | 9993 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 9994 | Expressions => New_List ( |
9995 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 9996 | end Get_N_First; |
9997 | ||
9998 | ---------------- | |
9999 | -- Get_N_Last -- | |
10000 | ---------------- | |
10001 | ||
10002 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is | |
10003 | begin | |
10004 | return | |
10005 | Make_Attribute_Reference (Loc, | |
10006 | Attribute_Name => Name_Last, | |
10007 | Prefix => | |
9dfe12ae | 10008 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 10009 | Expressions => New_List ( |
10010 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 10011 | end Get_N_Last; |
10012 | ||
10013 | ------------------ | |
10014 | -- Range_E_Cond -- | |
10015 | ------------------ | |
10016 | ||
10017 | function Range_E_Cond | |
10018 | (Exptyp : Entity_Id; | |
10019 | Typ : Entity_Id; | |
314a23b6 | 10020 | Indx : Nat) return Node_Id |
ee6ba406 | 10021 | is |
10022 | begin | |
10023 | return | |
10024 | Make_Or_Else (Loc, | |
10025 | Left_Opnd => | |
10026 | Make_Op_Lt (Loc, | |
3cb12758 | 10027 | Left_Opnd => |
10028 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First), | |
10029 | Right_Opnd => | |
10030 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
ee6ba406 | 10031 | |
10032 | Right_Opnd => | |
10033 | Make_Op_Gt (Loc, | |
3cb12758 | 10034 | Left_Opnd => |
10035 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last), | |
10036 | Right_Opnd => | |
10037 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 10038 | end Range_E_Cond; |
10039 | ||
10040 | ------------------------ | |
10041 | -- Range_Equal_E_Cond -- | |
10042 | ------------------------ | |
10043 | ||
10044 | function Range_Equal_E_Cond | |
10045 | (Exptyp : Entity_Id; | |
10046 | Typ : Entity_Id; | |
314a23b6 | 10047 | Indx : Nat) return Node_Id |
ee6ba406 | 10048 | is |
10049 | begin | |
10050 | return | |
10051 | Make_Or_Else (Loc, | |
10052 | Left_Opnd => | |
10053 | Make_Op_Ne (Loc, | |
3cb12758 | 10054 | Left_Opnd => |
10055 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First), | |
10056 | Right_Opnd => | |
10057 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
10058 | ||
ee6ba406 | 10059 | Right_Opnd => |
10060 | Make_Op_Ne (Loc, | |
3cb12758 | 10061 | Left_Opnd => |
10062 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last), | |
10063 | Right_Opnd => | |
10064 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 10065 | end Range_Equal_E_Cond; |
10066 | ||
10067 | ------------------ | |
10068 | -- Range_N_Cond -- | |
10069 | ------------------ | |
10070 | ||
10071 | function Range_N_Cond | |
10072 | (Expr : Node_Id; | |
10073 | Typ : Entity_Id; | |
314a23b6 | 10074 | Indx : Nat) return Node_Id |
ee6ba406 | 10075 | is |
10076 | begin | |
10077 | return | |
10078 | Make_Or_Else (Loc, | |
10079 | Left_Opnd => | |
10080 | Make_Op_Lt (Loc, | |
3cb12758 | 10081 | Left_Opnd => |
10082 | Get_N_First (Expr, Indx), | |
10083 | Right_Opnd => | |
10084 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
ee6ba406 | 10085 | |
10086 | Right_Opnd => | |
10087 | Make_Op_Gt (Loc, | |
3cb12758 | 10088 | Left_Opnd => |
10089 | Get_N_Last (Expr, Indx), | |
10090 | Right_Opnd => | |
10091 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 10092 | end Range_N_Cond; |
10093 | ||
10094 | -- Start of processing for Selected_Range_Checks | |
10095 | ||
10096 | begin | |
f0d65dae | 10097 | -- Checks will be applied only when generating code. In GNATprove mode, |
10098 | -- we do not apply the checks, but we still call Selected_Range_Checks | |
10099 | -- to possibly issue errors on SPARK code when a run-time error can be | |
10100 | -- detected at compile time. | |
10101 | ||
10102 | if not Expander_Active and not GNATprove_Mode then | |
ee6ba406 | 10103 | return Ret_Result; |
10104 | end if; | |
10105 | ||
10106 | if Target_Typ = Any_Type | |
10107 | or else Target_Typ = Any_Composite | |
10108 | or else Raises_Constraint_Error (Ck_Node) | |
10109 | then | |
10110 | return Ret_Result; | |
10111 | end if; | |
10112 | ||
10113 | if No (Wnode) then | |
10114 | Wnode := Ck_Node; | |
10115 | end if; | |
10116 | ||
10117 | T_Typ := Target_Typ; | |
10118 | ||
10119 | if No (Source_Typ) then | |
10120 | S_Typ := Etype (Ck_Node); | |
10121 | else | |
10122 | S_Typ := Source_Typ; | |
10123 | end if; | |
10124 | ||
10125 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
10126 | return Ret_Result; | |
10127 | end if; | |
10128 | ||
10129 | -- The order of evaluating T_Typ before S_Typ seems to be critical | |
10130 | -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed | |
10131 | -- in, and since Node can be an N_Range node, it might be invalid. | |
10132 | -- Should there be an assert check somewhere for taking the Etype of | |
10133 | -- an N_Range node ??? | |
10134 | ||
10135 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
10136 | S_Typ := Designated_Type (S_Typ); | |
10137 | T_Typ := Designated_Type (T_Typ); | |
10138 | Do_Access := True; | |
10139 | ||
2af58f67 | 10140 | -- A simple optimization for the null case |
ee6ba406 | 10141 | |
2af58f67 | 10142 | if Known_Null (Ck_Node) then |
ee6ba406 | 10143 | return Ret_Result; |
10144 | end if; | |
10145 | end if; | |
10146 | ||
10147 | -- For an N_Range Node, check for a null range and then if not | |
10148 | -- null generate a range check action. | |
10149 | ||
10150 | if Nkind (Ck_Node) = N_Range then | |
10151 | ||
10152 | -- There's no point in checking a range against itself | |
10153 | ||
10154 | if Ck_Node = Scalar_Range (T_Typ) then | |
10155 | return Ret_Result; | |
10156 | end if; | |
10157 | ||
10158 | declare | |
10159 | T_LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
10160 | T_HB : constant Node_Id := Type_High_Bound (T_Typ); | |
eefa141b | 10161 | Known_T_LB : constant Boolean := Compile_Time_Known_Value (T_LB); |
10162 | Known_T_HB : constant Boolean := Compile_Time_Known_Value (T_HB); | |
ee6ba406 | 10163 | |
eefa141b | 10164 | LB : Node_Id := Low_Bound (Ck_Node); |
10165 | HB : Node_Id := High_Bound (Ck_Node); | |
3fabf0ca | 10166 | Known_LB : Boolean := False; |
10167 | Known_HB : Boolean := False; | |
eefa141b | 10168 | |
10169 | Null_Range : Boolean; | |
ee6ba406 | 10170 | Out_Of_Range_L : Boolean; |
10171 | Out_Of_Range_H : Boolean; | |
10172 | ||
10173 | begin | |
eefa141b | 10174 | -- Compute what is known at compile time |
10175 | ||
10176 | if Known_T_LB and Known_T_HB then | |
10177 | if Compile_Time_Known_Value (LB) then | |
10178 | Known_LB := True; | |
10179 | ||
10180 | -- There's no point in checking that a bound is within its | |
10181 | -- own range so pretend that it is known in this case. First | |
10182 | -- deal with low bound. | |
10183 | ||
10184 | elsif Ekind (Etype (LB)) = E_Signed_Integer_Subtype | |
10185 | and then Scalar_Range (Etype (LB)) = Scalar_Range (T_Typ) | |
10186 | then | |
10187 | LB := T_LB; | |
10188 | Known_LB := True; | |
eefa141b | 10189 | end if; |
10190 | ||
10191 | -- Likewise for the high bound | |
10192 | ||
10193 | if Compile_Time_Known_Value (HB) then | |
10194 | Known_HB := True; | |
10195 | ||
10196 | elsif Ekind (Etype (HB)) = E_Signed_Integer_Subtype | |
10197 | and then Scalar_Range (Etype (HB)) = Scalar_Range (T_Typ) | |
10198 | then | |
10199 | HB := T_HB; | |
10200 | Known_HB := True; | |
eefa141b | 10201 | end if; |
10202 | end if; | |
10203 | ||
10204 | -- Check for case where everything is static and we can do the | |
10205 | -- check at compile time. This is skipped if we have an access | |
10206 | -- type, since the access value may be null. | |
10207 | ||
10208 | -- ??? This code can be improved since you only need to know that | |
10209 | -- the two respective bounds (LB & T_LB or HB & T_HB) are known at | |
10210 | -- compile time to emit pertinent messages. | |
10211 | ||
10212 | if Known_T_LB and Known_T_HB and Known_LB and Known_HB | |
10213 | and not Do_Access | |
ee6ba406 | 10214 | then |
10215 | -- Floating-point case | |
10216 | ||
10217 | if Is_Floating_Point_Type (S_Typ) then | |
10218 | Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB); | |
10219 | Out_Of_Range_L := | |
10220 | (Expr_Value_R (LB) < Expr_Value_R (T_LB)) | |
eefa141b | 10221 | or else |
ee6ba406 | 10222 | (Expr_Value_R (LB) > Expr_Value_R (T_HB)); |
10223 | ||
10224 | Out_Of_Range_H := | |
10225 | (Expr_Value_R (HB) > Expr_Value_R (T_HB)) | |
eefa141b | 10226 | or else |
ee6ba406 | 10227 | (Expr_Value_R (HB) < Expr_Value_R (T_LB)); |
10228 | ||
10229 | -- Fixed or discrete type case | |
10230 | ||
10231 | else | |
10232 | Null_Range := Expr_Value (HB) < Expr_Value (LB); | |
10233 | Out_Of_Range_L := | |
10234 | (Expr_Value (LB) < Expr_Value (T_LB)) | |
eefa141b | 10235 | or else |
ee6ba406 | 10236 | (Expr_Value (LB) > Expr_Value (T_HB)); |
10237 | ||
10238 | Out_Of_Range_H := | |
10239 | (Expr_Value (HB) > Expr_Value (T_HB)) | |
eefa141b | 10240 | or else |
ee6ba406 | 10241 | (Expr_Value (HB) < Expr_Value (T_LB)); |
10242 | end if; | |
10243 | ||
10244 | if not Null_Range then | |
10245 | if Out_Of_Range_L then | |
10246 | if No (Warn_Node) then | |
10247 | Add_Check | |
10248 | (Compile_Time_Constraint_Error | |
10249 | (Low_Bound (Ck_Node), | |
cb97ae5c | 10250 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 10251 | |
10252 | else | |
10253 | Add_Check | |
10254 | (Compile_Time_Constraint_Error | |
10255 | (Wnode, | |
cb97ae5c | 10256 | "static range out of bounds of}??", T_Typ)); |
ee6ba406 | 10257 | end if; |
10258 | end if; | |
10259 | ||
10260 | if Out_Of_Range_H then | |
10261 | if No (Warn_Node) then | |
10262 | Add_Check | |
10263 | (Compile_Time_Constraint_Error | |
10264 | (High_Bound (Ck_Node), | |
cb97ae5c | 10265 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 10266 | |
10267 | else | |
10268 | Add_Check | |
10269 | (Compile_Time_Constraint_Error | |
10270 | (Wnode, | |
cb97ae5c | 10271 | "static range out of bounds of}??", T_Typ)); |
ee6ba406 | 10272 | end if; |
10273 | end if; | |
ee6ba406 | 10274 | end if; |
10275 | ||
10276 | else | |
10277 | declare | |
10278 | LB : Node_Id := Low_Bound (Ck_Node); | |
10279 | HB : Node_Id := High_Bound (Ck_Node); | |
10280 | ||
10281 | begin | |
feff2f05 | 10282 | -- If either bound is a discriminant and we are within the |
10283 | -- record declaration, it is a use of the discriminant in a | |
10284 | -- constraint of a component, and nothing can be checked | |
10285 | -- here. The check will be emitted within the init proc. | |
10286 | -- Before then, the discriminal has no real meaning. | |
10287 | -- Similarly, if the entity is a discriminal, there is no | |
10288 | -- check to perform yet. | |
10289 | ||
10290 | -- The same holds within a discriminated synchronized type, | |
10291 | -- where the discriminant may constrain a component or an | |
10292 | -- entry family. | |
ee6ba406 | 10293 | |
10294 | if Nkind (LB) = N_Identifier | |
0577b0b1 | 10295 | and then Denotes_Discriminant (LB, True) |
ee6ba406 | 10296 | then |
0577b0b1 | 10297 | if Current_Scope = Scope (Entity (LB)) |
10298 | or else Is_Concurrent_Type (Current_Scope) | |
10299 | or else Ekind (Entity (LB)) /= E_Discriminant | |
10300 | then | |
ee6ba406 | 10301 | return Ret_Result; |
10302 | else | |
10303 | LB := | |
10304 | New_Occurrence_Of (Discriminal (Entity (LB)), Loc); | |
10305 | end if; | |
10306 | end if; | |
10307 | ||
10308 | if Nkind (HB) = N_Identifier | |
0577b0b1 | 10309 | and then Denotes_Discriminant (HB, True) |
ee6ba406 | 10310 | then |
0577b0b1 | 10311 | if Current_Scope = Scope (Entity (HB)) |
10312 | or else Is_Concurrent_Type (Current_Scope) | |
10313 | or else Ekind (Entity (HB)) /= E_Discriminant | |
10314 | then | |
ee6ba406 | 10315 | return Ret_Result; |
10316 | else | |
10317 | HB := | |
10318 | New_Occurrence_Of (Discriminal (Entity (HB)), Loc); | |
10319 | end if; | |
10320 | end if; | |
10321 | ||
10322 | Cond := Discrete_Range_Cond (Ck_Node, T_Typ); | |
10323 | Set_Paren_Count (Cond, 1); | |
10324 | ||
10325 | Cond := | |
10326 | Make_And_Then (Loc, | |
10327 | Left_Opnd => | |
10328 | Make_Op_Ge (Loc, | |
86d32751 | 10329 | Left_Opnd => |
10330 | Convert_To (Base_Type (Etype (HB)), | |
10331 | Duplicate_Subexpr_No_Checks (HB)), | |
10332 | Right_Opnd => | |
10333 | Convert_To (Base_Type (Etype (LB)), | |
10334 | Duplicate_Subexpr_No_Checks (LB))), | |
ee6ba406 | 10335 | Right_Opnd => Cond); |
10336 | end; | |
ee6ba406 | 10337 | end if; |
10338 | end; | |
10339 | ||
10340 | elsif Is_Scalar_Type (S_Typ) then | |
10341 | ||
10342 | -- This somewhat duplicates what Apply_Scalar_Range_Check does, | |
10343 | -- except the above simply sets a flag in the node and lets | |
10344 | -- gigi generate the check base on the Etype of the expression. | |
10345 | -- Sometimes, however we want to do a dynamic check against an | |
10346 | -- arbitrary target type, so we do that here. | |
10347 | ||
10348 | if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then | |
10349 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
10350 | ||
10351 | -- For literals, we can tell if the constraint error will be | |
10352 | -- raised at compile time, so we never need a dynamic check, but | |
10353 | -- if the exception will be raised, then post the usual warning, | |
10354 | -- and replace the literal with a raise constraint error | |
10355 | -- expression. As usual, skip this for access types | |
10356 | ||
20cf157b | 10357 | elsif Compile_Time_Known_Value (Ck_Node) and then not Do_Access then |
ee6ba406 | 10358 | declare |
10359 | LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
10360 | UB : constant Node_Id := Type_High_Bound (T_Typ); | |
10361 | ||
10362 | Out_Of_Range : Boolean; | |
10363 | Static_Bounds : constant Boolean := | |
b6341c67 | 10364 | Compile_Time_Known_Value (LB) |
10365 | and Compile_Time_Known_Value (UB); | |
ee6ba406 | 10366 | |
10367 | begin | |
10368 | -- Following range tests should use Sem_Eval routine ??? | |
10369 | ||
10370 | if Static_Bounds then | |
10371 | if Is_Floating_Point_Type (S_Typ) then | |
10372 | Out_Of_Range := | |
10373 | (Expr_Value_R (Ck_Node) < Expr_Value_R (LB)) | |
10374 | or else | |
10375 | (Expr_Value_R (Ck_Node) > Expr_Value_R (UB)); | |
10376 | ||
eefa141b | 10377 | -- Fixed or discrete type |
10378 | ||
10379 | else | |
ee6ba406 | 10380 | Out_Of_Range := |
10381 | Expr_Value (Ck_Node) < Expr_Value (LB) | |
10382 | or else | |
10383 | Expr_Value (Ck_Node) > Expr_Value (UB); | |
10384 | end if; | |
10385 | ||
eefa141b | 10386 | -- Bounds of the type are static and the literal is out of |
10387 | -- range so output a warning message. | |
ee6ba406 | 10388 | |
10389 | if Out_Of_Range then | |
10390 | if No (Warn_Node) then | |
10391 | Add_Check | |
10392 | (Compile_Time_Constraint_Error | |
10393 | (Ck_Node, | |
cb97ae5c | 10394 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 10395 | |
10396 | else | |
10397 | Add_Check | |
10398 | (Compile_Time_Constraint_Error | |
10399 | (Wnode, | |
cb97ae5c | 10400 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 10401 | end if; |
10402 | end if; | |
10403 | ||
10404 | else | |
10405 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
10406 | end if; | |
10407 | end; | |
10408 | ||
10409 | -- Here for the case of a non-static expression, we need a runtime | |
10410 | -- check unless the source type range is guaranteed to be in the | |
10411 | -- range of the target type. | |
10412 | ||
10413 | else | |
7a1dabb3 | 10414 | if not In_Subrange_Of (S_Typ, T_Typ) then |
ee6ba406 | 10415 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); |
10416 | end if; | |
10417 | end if; | |
10418 | end if; | |
10419 | ||
10420 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
10421 | if Is_Constrained (T_Typ) then | |
10422 | ||
10423 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
10424 | Exptyp := Get_Actual_Subtype (Expr_Actual); | |
10425 | ||
10426 | if Is_Access_Type (Exptyp) then | |
10427 | Exptyp := Designated_Type (Exptyp); | |
10428 | end if; | |
10429 | ||
10430 | -- String_Literal case. This needs to be handled specially be- | |
10431 | -- cause no index types are available for string literals. The | |
10432 | -- condition is simply: | |
10433 | ||
10434 | -- T_Typ'Length = string-literal-length | |
10435 | ||
10436 | if Nkind (Expr_Actual) = N_String_Literal then | |
10437 | null; | |
10438 | ||
10439 | -- General array case. Here we have a usable actual subtype for | |
10440 | -- the expression, and the condition is built from the two types | |
10441 | ||
10442 | -- T_Typ'First < Exptyp'First or else | |
10443 | -- T_Typ'Last > Exptyp'Last or else | |
10444 | -- T_Typ'First(1) < Exptyp'First(1) or else | |
10445 | -- T_Typ'Last(1) > Exptyp'Last(1) or else | |
10446 | -- ... | |
10447 | ||
10448 | elsif Is_Constrained (Exptyp) then | |
10449 | declare | |
9dfe12ae | 10450 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
10451 | ||
ee6ba406 | 10452 | L_Index : Node_Id; |
10453 | R_Index : Node_Id; | |
ee6ba406 | 10454 | |
10455 | begin | |
10456 | L_Index := First_Index (T_Typ); | |
10457 | R_Index := First_Index (Exptyp); | |
10458 | ||
10459 | for Indx in 1 .. Ndims loop | |
10460 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 10461 | or else |
10462 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 10463 | then |
ee6ba406 | 10464 | -- Deal with compile time length check. Note that we |
10465 | -- skip this in the access case, because the access | |
10466 | -- value may be null, so we cannot know statically. | |
10467 | ||
10468 | if not | |
10469 | Subtypes_Statically_Match | |
10470 | (Etype (L_Index), Etype (R_Index)) | |
10471 | then | |
10472 | -- If the target type is constrained then we | |
10473 | -- have to check for exact equality of bounds | |
10474 | -- (required for qualified expressions). | |
10475 | ||
10476 | if Is_Constrained (T_Typ) then | |
10477 | Evolve_Or_Else | |
10478 | (Cond, | |
10479 | Range_Equal_E_Cond (Exptyp, T_Typ, Indx)); | |
ee6ba406 | 10480 | else |
10481 | Evolve_Or_Else | |
10482 | (Cond, Range_E_Cond (Exptyp, T_Typ, Indx)); | |
10483 | end if; | |
10484 | end if; | |
10485 | ||
10486 | Next (L_Index); | |
10487 | Next (R_Index); | |
ee6ba406 | 10488 | end if; |
10489 | end loop; | |
10490 | end; | |
10491 | ||
10492 | -- Handle cases where we do not get a usable actual subtype that | |
10493 | -- is constrained. This happens for example in the function call | |
10494 | -- and explicit dereference cases. In these cases, we have to get | |
10495 | -- the length or range from the expression itself, making sure we | |
10496 | -- do not evaluate it more than once. | |
10497 | ||
10498 | -- Here Ck_Node is the original expression, or more properly the | |
10499 | -- result of applying Duplicate_Expr to the original tree, | |
10500 | -- forcing the result to be a name. | |
10501 | ||
10502 | else | |
10503 | declare | |
9dfe12ae | 10504 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 10505 | |
10506 | begin | |
10507 | -- Build the condition for the explicit dereference case | |
10508 | ||
10509 | for Indx in 1 .. Ndims loop | |
10510 | Evolve_Or_Else | |
10511 | (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx)); | |
10512 | end loop; | |
10513 | end; | |
ee6ba406 | 10514 | end if; |
10515 | ||
10516 | else | |
feff2f05 | 10517 | -- For a conversion to an unconstrained array type, generate an |
10518 | -- Action to check that the bounds of the source value are within | |
10519 | -- the constraints imposed by the target type (RM 4.6(38)). No | |
10520 | -- check is needed for a conversion to an access to unconstrained | |
10521 | -- array type, as 4.6(24.15/2) requires the designated subtypes | |
10522 | -- of the two access types to statically match. | |
10523 | ||
10524 | if Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
10525 | and then not Do_Access | |
10526 | then | |
ee6ba406 | 10527 | declare |
10528 | Opnd_Index : Node_Id; | |
10529 | Targ_Index : Node_Id; | |
00c403ee | 10530 | Opnd_Range : Node_Id; |
ee6ba406 | 10531 | |
10532 | begin | |
feff2f05 | 10533 | Opnd_Index := First_Index (Get_Actual_Subtype (Ck_Node)); |
ee6ba406 | 10534 | Targ_Index := First_Index (T_Typ); |
00c403ee | 10535 | while Present (Opnd_Index) loop |
10536 | ||
10537 | -- If the index is a range, use its bounds. If it is an | |
10538 | -- entity (as will be the case if it is a named subtype | |
10539 | -- or an itype created for a slice) retrieve its range. | |
10540 | ||
10541 | if Is_Entity_Name (Opnd_Index) | |
10542 | and then Is_Type (Entity (Opnd_Index)) | |
10543 | then | |
10544 | Opnd_Range := Scalar_Range (Entity (Opnd_Index)); | |
10545 | else | |
10546 | Opnd_Range := Opnd_Index; | |
10547 | end if; | |
10548 | ||
10549 | if Nkind (Opnd_Range) = N_Range then | |
9c486805 | 10550 | if Is_In_Range |
10551 | (Low_Bound (Opnd_Range), Etype (Targ_Index), | |
10552 | Assume_Valid => True) | |
ee6ba406 | 10553 | and then |
10554 | Is_In_Range | |
9c486805 | 10555 | (High_Bound (Opnd_Range), Etype (Targ_Index), |
10556 | Assume_Valid => True) | |
ee6ba406 | 10557 | then |
10558 | null; | |
10559 | ||
feff2f05 | 10560 | -- If null range, no check needed |
f2a06be9 | 10561 | |
9dfe12ae | 10562 | elsif |
00c403ee | 10563 | Compile_Time_Known_Value (High_Bound (Opnd_Range)) |
9dfe12ae | 10564 | and then |
00c403ee | 10565 | Compile_Time_Known_Value (Low_Bound (Opnd_Range)) |
9dfe12ae | 10566 | and then |
00c403ee | 10567 | Expr_Value (High_Bound (Opnd_Range)) < |
10568 | Expr_Value (Low_Bound (Opnd_Range)) | |
9dfe12ae | 10569 | then |
10570 | null; | |
10571 | ||
ee6ba406 | 10572 | elsif Is_Out_Of_Range |
9c486805 | 10573 | (Low_Bound (Opnd_Range), Etype (Targ_Index), |
10574 | Assume_Valid => True) | |
ee6ba406 | 10575 | or else |
10576 | Is_Out_Of_Range | |
9c486805 | 10577 | (High_Bound (Opnd_Range), Etype (Targ_Index), |
10578 | Assume_Valid => True) | |
ee6ba406 | 10579 | then |
10580 | Add_Check | |
10581 | (Compile_Time_Constraint_Error | |
cb97ae5c | 10582 | (Wnode, "value out of range of}??", T_Typ)); |
ee6ba406 | 10583 | |
10584 | else | |
10585 | Evolve_Or_Else | |
10586 | (Cond, | |
10587 | Discrete_Range_Cond | |
00c403ee | 10588 | (Opnd_Range, Etype (Targ_Index))); |
ee6ba406 | 10589 | end if; |
10590 | end if; | |
10591 | ||
10592 | Next_Index (Opnd_Index); | |
10593 | Next_Index (Targ_Index); | |
10594 | end loop; | |
10595 | end; | |
10596 | end if; | |
10597 | end if; | |
10598 | end if; | |
10599 | ||
10600 | -- Construct the test and insert into the tree | |
10601 | ||
10602 | if Present (Cond) then | |
10603 | if Do_Access then | |
10604 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
10605 | end if; | |
10606 | ||
f15731c4 | 10607 | Add_Check |
10608 | (Make_Raise_Constraint_Error (Loc, | |
eefa141b | 10609 | Condition => Cond, |
22d3a5a3 | 10610 | Reason => CE_Range_Check_Failed)); |
ee6ba406 | 10611 | end if; |
10612 | ||
10613 | return Ret_Result; | |
ee6ba406 | 10614 | end Selected_Range_Checks; |
10615 | ||
10616 | ------------------------------- | |
10617 | -- Storage_Checks_Suppressed -- | |
10618 | ------------------------------- | |
10619 | ||
10620 | function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is | |
10621 | begin | |
9dfe12ae | 10622 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
10623 | return Is_Check_Suppressed (E, Storage_Check); | |
10624 | else | |
fafc6b97 | 10625 | return Scope_Suppress.Suppress (Storage_Check); |
9dfe12ae | 10626 | end if; |
ee6ba406 | 10627 | end Storage_Checks_Suppressed; |
10628 | ||
10629 | --------------------------- | |
10630 | -- Tag_Checks_Suppressed -- | |
10631 | --------------------------- | |
10632 | ||
10633 | function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is | |
10634 | begin | |
89f1e35c | 10635 | if Present (E) |
10636 | and then Checks_May_Be_Suppressed (E) | |
10637 | then | |
10638 | return Is_Check_Suppressed (E, Tag_Check); | |
20cf157b | 10639 | else |
10640 | return Scope_Suppress.Suppress (Tag_Check); | |
9dfe12ae | 10641 | end if; |
ee6ba406 | 10642 | end Tag_Checks_Suppressed; |
10643 | ||
7b8fa048 | 10644 | --------------------------------------- |
10645 | -- Validate_Alignment_Check_Warnings -- | |
10646 | --------------------------------------- | |
10647 | ||
10648 | procedure Validate_Alignment_Check_Warnings is | |
10649 | begin | |
10650 | for J in Alignment_Warnings.First .. Alignment_Warnings.Last loop | |
10651 | declare | |
10652 | AWR : Alignment_Warnings_Record | |
10653 | renames Alignment_Warnings.Table (J); | |
10654 | begin | |
10655 | if Known_Alignment (AWR.E) | |
10656 | and then AWR.A mod Alignment (AWR.E) = 0 | |
10657 | then | |
10658 | Delete_Warning_And_Continuations (AWR.W); | |
10659 | end if; | |
10660 | end; | |
10661 | end loop; | |
10662 | end Validate_Alignment_Check_Warnings; | |
10663 | ||
0577b0b1 | 10664 | -------------------------- |
10665 | -- Validity_Check_Range -- | |
10666 | -------------------------- | |
10667 | ||
aaec8d13 | 10668 | procedure Validity_Check_Range |
10669 | (N : Node_Id; | |
10670 | Related_Id : Entity_Id := Empty) | |
10671 | is | |
0577b0b1 | 10672 | begin |
10673 | if Validity_Checks_On and Validity_Check_Operands then | |
10674 | if Nkind (N) = N_Range then | |
aaec8d13 | 10675 | Ensure_Valid |
10676 | (Expr => Low_Bound (N), | |
10677 | Related_Id => Related_Id, | |
10678 | Is_Low_Bound => True); | |
10679 | ||
10680 | Ensure_Valid | |
10681 | (Expr => High_Bound (N), | |
10682 | Related_Id => Related_Id, | |
10683 | Is_High_Bound => True); | |
0577b0b1 | 10684 | end if; |
10685 | end if; | |
10686 | end Validity_Check_Range; | |
10687 | ||
10688 | -------------------------------- | |
10689 | -- Validity_Checks_Suppressed -- | |
10690 | -------------------------------- | |
10691 | ||
10692 | function Validity_Checks_Suppressed (E : Entity_Id) return Boolean is | |
10693 | begin | |
10694 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
10695 | return Is_Check_Suppressed (E, Validity_Check); | |
10696 | else | |
fafc6b97 | 10697 | return Scope_Suppress.Suppress (Validity_Check); |
0577b0b1 | 10698 | end if; |
10699 | end Validity_Checks_Suppressed; | |
10700 | ||
ee6ba406 | 10701 | end Checks; |