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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 | -- -- | |
1581f2d7 | 9 | -- Copyright (C) 1992-2014, 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; |
7b8fa048 | 51 | with Sem_Eval; use Sem_Eval; |
ee6ba406 | 52 | with Sem_Res; use Sem_Res; |
53 | with Sem_Util; use Sem_Util; | |
54 | with Sem_Warn; use Sem_Warn; | |
55 | with Sinfo; use Sinfo; | |
9dfe12ae | 56 | with Sinput; use Sinput; |
ee6ba406 | 57 | with Snames; use Snames; |
9dfe12ae | 58 | with Sprint; use Sprint; |
ee6ba406 | 59 | with Stand; use Stand; |
bb569db0 | 60 | with Stringt; use Stringt; |
f15731c4 | 61 | with Targparm; use Targparm; |
ee6ba406 | 62 | with Tbuild; use Tbuild; |
63 | with Ttypes; use Ttypes; | |
ee6ba406 | 64 | with Validsw; use Validsw; |
65 | ||
66 | package body Checks is | |
67 | ||
68 | -- General note: many of these routines are concerned with generating | |
69 | -- checking code to make sure that constraint error is raised at runtime. | |
70 | -- Clearly this code is only needed if the expander is active, since | |
71 | -- otherwise we will not be generating code or going into the runtime | |
72 | -- execution anyway. | |
73 | ||
74 | -- We therefore disconnect most of these checks if the expander is | |
75 | -- inactive. This has the additional benefit that we do not need to | |
76 | -- worry about the tree being messed up by previous errors (since errors | |
77 | -- turn off expansion anyway). | |
78 | ||
79 | -- There are a few exceptions to the above rule. For instance routines | |
80 | -- such as Apply_Scalar_Range_Check that do not insert any code can be | |
81 | -- safely called even when the Expander is inactive (but Errors_Detected | |
82 | -- is 0). The benefit of executing this code when expansion is off, is | |
83 | -- the ability to emit constraint error warning for static expressions | |
84 | -- even when we are not generating code. | |
85 | ||
20cf157b | 86 | -- The above is modified in gnatprove mode to ensure that proper check |
87 | -- flags are always placed, even if expansion is off. | |
88 | ||
9dfe12ae | 89 | ------------------------------------- |
90 | -- Suppression of Redundant Checks -- | |
91 | ------------------------------------- | |
92 | ||
93 | -- This unit implements a limited circuit for removal of redundant | |
94 | -- checks. The processing is based on a tracing of simple sequential | |
95 | -- flow. For any sequence of statements, we save expressions that are | |
96 | -- marked to be checked, and then if the same expression appears later | |
97 | -- with the same check, then under certain circumstances, the second | |
98 | -- check can be suppressed. | |
99 | ||
100 | -- Basically, we can suppress the check if we know for certain that | |
101 | -- the previous expression has been elaborated (together with its | |
102 | -- check), and we know that the exception frame is the same, and that | |
103 | -- nothing has happened to change the result of the exception. | |
104 | ||
105 | -- Let us examine each of these three conditions in turn to describe | |
106 | -- how we ensure that this condition is met. | |
107 | ||
108 | -- First, we need to know for certain that the previous expression has | |
6fb3c314 | 109 | -- been executed. This is done principally by the mechanism of calling |
9dfe12ae | 110 | -- Conditional_Statements_Begin at the start of any statement sequence |
111 | -- and Conditional_Statements_End at the end. The End call causes all | |
112 | -- checks remembered since the Begin call to be discarded. This does | |
113 | -- miss a few cases, notably the case of a nested BEGIN-END block with | |
114 | -- no exception handlers. But the important thing is to be conservative. | |
115 | -- The other protection is that all checks are discarded if a label | |
116 | -- is encountered, since then the assumption of sequential execution | |
117 | -- is violated, and we don't know enough about the flow. | |
118 | ||
119 | -- Second, we need to know that the exception frame is the same. We | |
120 | -- do this by killing all remembered checks when we enter a new frame. | |
121 | -- Again, that's over-conservative, but generally the cases we can help | |
122 | -- with are pretty local anyway (like the body of a loop for example). | |
123 | ||
124 | -- Third, we must be sure to forget any checks which are no longer valid. | |
125 | -- This is done by two mechanisms, first the Kill_Checks_Variable call is | |
126 | -- used to note any changes to local variables. We only attempt to deal | |
127 | -- with checks involving local variables, so we do not need to worry | |
128 | -- about global variables. Second, a call to any non-global procedure | |
129 | -- causes us to abandon all stored checks, since such a all may affect | |
130 | -- the values of any local variables. | |
131 | ||
132 | -- The following define the data structures used to deal with remembering | |
133 | -- checks so that redundant checks can be eliminated as described above. | |
134 | ||
135 | -- Right now, the only expressions that we deal with are of the form of | |
136 | -- simple local objects (either declared locally, or IN parameters) or | |
137 | -- such objects plus/minus a compile time known constant. We can do | |
138 | -- more later on if it seems worthwhile, but this catches many simple | |
139 | -- cases in practice. | |
140 | ||
141 | -- The following record type reflects a single saved check. An entry | |
142 | -- is made in the stack of saved checks if and only if the expression | |
143 | -- has been elaborated with the indicated checks. | |
144 | ||
145 | type Saved_Check is record | |
146 | Killed : Boolean; | |
147 | -- Set True if entry is killed by Kill_Checks | |
148 | ||
149 | Entity : Entity_Id; | |
150 | -- The entity involved in the expression that is checked | |
151 | ||
152 | Offset : Uint; | |
153 | -- A compile time value indicating the result of adding or | |
154 | -- subtracting a compile time value. This value is to be | |
155 | -- added to the value of the Entity. A value of zero is | |
156 | -- used for the case of a simple entity reference. | |
157 | ||
158 | Check_Type : Character; | |
159 | -- This is set to 'R' for a range check (in which case Target_Type | |
160 | -- is set to the target type for the range check) or to 'O' for an | |
161 | -- overflow check (in which case Target_Type is set to Empty). | |
162 | ||
163 | Target_Type : Entity_Id; | |
164 | -- Used only if Do_Range_Check is set. Records the target type for | |
165 | -- the check. We need this, because a check is a duplicate only if | |
6fb3c314 | 166 | -- it has the same target type (or more accurately one with a |
9dfe12ae | 167 | -- range that is smaller or equal to the stored target type of a |
168 | -- saved check). | |
169 | end record; | |
170 | ||
171 | -- The following table keeps track of saved checks. Rather than use an | |
172 | -- extensible table. We just use a table of fixed size, and we discard | |
173 | -- any saved checks that do not fit. That's very unlikely to happen and | |
174 | -- this is only an optimization in any case. | |
175 | ||
176 | Saved_Checks : array (Int range 1 .. 200) of Saved_Check; | |
177 | -- Array of saved checks | |
178 | ||
179 | Num_Saved_Checks : Nat := 0; | |
180 | -- Number of saved checks | |
181 | ||
182 | -- The following stack keeps track of statement ranges. It is treated | |
183 | -- as a stack. When Conditional_Statements_Begin is called, an entry | |
184 | -- is pushed onto this stack containing the value of Num_Saved_Checks | |
185 | -- at the time of the call. Then when Conditional_Statements_End is | |
186 | -- called, this value is popped off and used to reset Num_Saved_Checks. | |
187 | ||
188 | -- Note: again, this is a fixed length stack with a size that should | |
189 | -- always be fine. If the value of the stack pointer goes above the | |
190 | -- limit, then we just forget all saved checks. | |
191 | ||
192 | Saved_Checks_Stack : array (Int range 1 .. 100) of Nat; | |
193 | Saved_Checks_TOS : Nat := 0; | |
194 | ||
195 | ----------------------- | |
196 | -- Local Subprograms -- | |
197 | ----------------------- | |
ee6ba406 | 198 | |
0df9d43f | 199 | procedure Apply_Arithmetic_Overflow_Strict (N : Node_Id); |
3cce7f32 | 200 | -- Used to apply arithmetic overflow checks for all cases except operators |
691fe9e0 | 201 | -- on signed arithmetic types in MINIMIZED/ELIMINATED case (for which we |
0df9d43f | 202 | -- call Apply_Arithmetic_Overflow_Minimized_Eliminated below). N can be a |
203 | -- signed integer arithmetic operator (but not an if or case expression). | |
204 | -- It is also called for types other than signed integers. | |
3cce7f32 | 205 | |
206 | procedure Apply_Arithmetic_Overflow_Minimized_Eliminated (Op : Node_Id); | |
207 | -- Used to apply arithmetic overflow checks for the case where the overflow | |
0df9d43f | 208 | -- checking mode is MINIMIZED or ELIMINATED and we have a signed integer |
209 | -- arithmetic op (which includes the case of if and case expressions). Note | |
210 | -- that Do_Overflow_Check may or may not be set for node Op. In these modes | |
211 | -- we have work to do even if overflow checking is suppressed. | |
3cce7f32 | 212 | |
2fe22c69 | 213 | procedure Apply_Division_Check |
214 | (N : Node_Id; | |
215 | Rlo : Uint; | |
216 | Rhi : Uint; | |
217 | ROK : Boolean); | |
218 | -- N is an N_Op_Div, N_Op_Rem, or N_Op_Mod node. This routine applies | |
219 | -- division checks as required if the Do_Division_Check flag is set. | |
220 | -- Rlo and Rhi give the possible range of the right operand, these values | |
221 | -- can be referenced and trusted only if ROK is set True. | |
222 | ||
223 | procedure Apply_Float_Conversion_Check | |
224 | (Ck_Node : Node_Id; | |
225 | Target_Typ : Entity_Id); | |
226 | -- The checks on a conversion from a floating-point type to an integer | |
227 | -- type are delicate. They have to be performed before conversion, they | |
228 | -- have to raise an exception when the operand is a NaN, and rounding must | |
229 | -- be taken into account to determine the safe bounds of the operand. | |
230 | ||
ee6ba406 | 231 | procedure Apply_Selected_Length_Checks |
232 | (Ck_Node : Node_Id; | |
233 | Target_Typ : Entity_Id; | |
234 | Source_Typ : Entity_Id; | |
235 | Do_Static : Boolean); | |
236 | -- This is the subprogram that does all the work for Apply_Length_Check | |
237 | -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as | |
238 | -- described for the above routines. The Do_Static flag indicates that | |
239 | -- only a static check is to be done. | |
240 | ||
241 | procedure Apply_Selected_Range_Checks | |
242 | (Ck_Node : Node_Id; | |
243 | Target_Typ : Entity_Id; | |
244 | Source_Typ : Entity_Id; | |
245 | Do_Static : Boolean); | |
246 | -- This is the subprogram that does all the work for Apply_Range_Check. | |
247 | -- Expr, Target_Typ and Source_Typ are as described for the above | |
248 | -- routine. The Do_Static flag indicates that only a static check is | |
249 | -- to be done. | |
250 | ||
2af58f67 | 251 | type Check_Type is new Check_Id range Access_Check .. Division_Check; |
13dbf220 | 252 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean; |
253 | -- This function is used to see if an access or division by zero check is | |
254 | -- needed. The check is to be applied to a single variable appearing in the | |
255 | -- source, and N is the node for the reference. If N is not of this form, | |
256 | -- True is returned with no further processing. If N is of the right form, | |
257 | -- then further processing determines if the given Check is needed. | |
258 | -- | |
259 | -- The particular circuit is to see if we have the case of a check that is | |
260 | -- not needed because it appears in the right operand of a short circuited | |
261 | -- conditional where the left operand guards the check. For example: | |
262 | -- | |
263 | -- if Var = 0 or else Q / Var > 12 then | |
264 | -- ... | |
265 | -- end if; | |
266 | -- | |
267 | -- In this example, the division check is not required. At the same time | |
268 | -- we can issue warnings for suspicious use of non-short-circuited forms, | |
269 | -- such as: | |
270 | -- | |
271 | -- if Var = 0 or Q / Var > 12 then | |
272 | -- ... | |
273 | -- end if; | |
274 | ||
9dfe12ae | 275 | procedure Find_Check |
276 | (Expr : Node_Id; | |
277 | Check_Type : Character; | |
278 | Target_Type : Entity_Id; | |
279 | Entry_OK : out Boolean; | |
280 | Check_Num : out Nat; | |
281 | Ent : out Entity_Id; | |
282 | Ofs : out Uint); | |
283 | -- This routine is used by Enable_Range_Check and Enable_Overflow_Check | |
284 | -- to see if a check is of the form for optimization, and if so, to see | |
285 | -- if it has already been performed. Expr is the expression to check, | |
286 | -- and Check_Type is 'R' for a range check, 'O' for an overflow check. | |
287 | -- Target_Type is the target type for a range check, and Empty for an | |
288 | -- overflow check. If the entry is not of the form for optimization, | |
289 | -- then Entry_OK is set to False, and the remaining out parameters | |
290 | -- are undefined. If the entry is OK, then Ent/Ofs are set to the | |
291 | -- entity and offset from the expression. Check_Num is the number of | |
292 | -- a matching saved entry in Saved_Checks, or zero if no such entry | |
293 | -- is located. | |
294 | ||
ee6ba406 | 295 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id; |
296 | -- If a discriminal is used in constraining a prival, Return reference | |
297 | -- to the discriminal of the protected body (which renames the parameter | |
298 | -- of the enclosing protected operation). This clumsy transformation is | |
299 | -- needed because privals are created too late and their actual subtypes | |
300 | -- are not available when analysing the bodies of the protected operations. | |
0577b0b1 | 301 | -- This function is called whenever the bound is an entity and the scope |
302 | -- indicates a protected operation. If the bound is an in-parameter of | |
303 | -- a protected operation that is not a prival, the function returns the | |
304 | -- bound itself. | |
ee6ba406 | 305 | -- To be cleaned up??? |
306 | ||
307 | function Guard_Access | |
308 | (Cond : Node_Id; | |
309 | Loc : Source_Ptr; | |
314a23b6 | 310 | Ck_Node : Node_Id) return Node_Id; |
ee6ba406 | 311 | -- In the access type case, guard the test with a test to ensure |
312 | -- that the access value is non-null, since the checks do not | |
313 | -- not apply to null access values. | |
314 | ||
315 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr); | |
316 | -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the | |
317 | -- Constraint_Error node. | |
318 | ||
3cce7f32 | 319 | function Is_Signed_Integer_Arithmetic_Op (N : Node_Id) return Boolean; |
320 | -- Returns True if node N is for an arithmetic operation with signed | |
0326b4d4 | 321 | -- integer operands. This includes unary and binary operators, and also |
322 | -- if and case expression nodes where the dependent expressions are of | |
323 | -- a signed integer type. These are the kinds of nodes for which special | |
691fe9e0 | 324 | -- handling applies in MINIMIZED or ELIMINATED overflow checking mode. |
3cce7f32 | 325 | |
0577b0b1 | 326 | function Range_Or_Validity_Checks_Suppressed |
327 | (Expr : Node_Id) return Boolean; | |
328 | -- Returns True if either range or validity checks or both are suppressed | |
329 | -- for the type of the given expression, or, if the expression is the name | |
330 | -- of an entity, if these checks are suppressed for the entity. | |
331 | ||
ee6ba406 | 332 | function Selected_Length_Checks |
333 | (Ck_Node : Node_Id; | |
334 | Target_Typ : Entity_Id; | |
335 | Source_Typ : Entity_Id; | |
314a23b6 | 336 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 337 | -- Like Apply_Selected_Length_Checks, except it doesn't modify |
338 | -- anything, just returns a list of nodes as described in the spec of | |
339 | -- this package for the Range_Check function. | |
340 | ||
341 | function Selected_Range_Checks | |
342 | (Ck_Node : Node_Id; | |
343 | Target_Typ : Entity_Id; | |
344 | Source_Typ : Entity_Id; | |
314a23b6 | 345 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 346 | -- Like Apply_Selected_Range_Checks, except it doesn't modify anything, |
347 | -- just returns a list of nodes as described in the spec of this package | |
348 | -- for the Range_Check function. | |
349 | ||
350 | ------------------------------ | |
351 | -- Access_Checks_Suppressed -- | |
352 | ------------------------------ | |
353 | ||
354 | function Access_Checks_Suppressed (E : Entity_Id) return Boolean is | |
355 | begin | |
9dfe12ae | 356 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
357 | return Is_Check_Suppressed (E, Access_Check); | |
358 | else | |
fafc6b97 | 359 | return Scope_Suppress.Suppress (Access_Check); |
9dfe12ae | 360 | end if; |
ee6ba406 | 361 | end Access_Checks_Suppressed; |
362 | ||
363 | ------------------------------------- | |
364 | -- Accessibility_Checks_Suppressed -- | |
365 | ------------------------------------- | |
366 | ||
367 | function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is | |
368 | begin | |
9dfe12ae | 369 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
370 | return Is_Check_Suppressed (E, Accessibility_Check); | |
371 | else | |
fafc6b97 | 372 | return Scope_Suppress.Suppress (Accessibility_Check); |
9dfe12ae | 373 | end if; |
ee6ba406 | 374 | end Accessibility_Checks_Suppressed; |
375 | ||
00c403ee | 376 | ----------------------------- |
377 | -- Activate_Division_Check -- | |
378 | ----------------------------- | |
379 | ||
380 | procedure Activate_Division_Check (N : Node_Id) is | |
381 | begin | |
382 | Set_Do_Division_Check (N, True); | |
383 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
384 | end Activate_Division_Check; | |
385 | ||
386 | ----------------------------- | |
387 | -- Activate_Overflow_Check -- | |
388 | ----------------------------- | |
389 | ||
390 | procedure Activate_Overflow_Check (N : Node_Id) is | |
c8e92b5f | 391 | Typ : constant Entity_Id := Etype (N); |
392 | ||
00c403ee | 393 | begin |
c8e92b5f | 394 | -- Floating-point case. If Etype is not set (this can happen when we |
395 | -- activate a check on a node that has not yet been analyzed), then | |
396 | -- we assume we do not have a floating-point type (as per our spec). | |
397 | ||
398 | if Present (Typ) and then Is_Floating_Point_Type (Typ) then | |
399 | ||
400 | -- Ignore call if we have no automatic overflow checks on the target | |
401 | -- and Check_Float_Overflow mode is not set. These are the cases in | |
402 | -- which we expect to generate infinities and NaN's with no check. | |
403 | ||
404 | if not (Machine_Overflows_On_Target or Check_Float_Overflow) then | |
405 | return; | |
406 | ||
407 | -- Ignore for unary operations ("+", "-", abs) since these can never | |
408 | -- result in overflow for floating-point cases. | |
b8446e0d | 409 | |
c8e92b5f | 410 | elsif Nkind (N) in N_Unary_Op then |
411 | return; | |
412 | ||
413 | -- Otherwise we will set the flag | |
414 | ||
415 | else | |
416 | null; | |
417 | end if; | |
418 | ||
419 | -- Discrete case | |
420 | ||
421 | else | |
422 | -- Nothing to do for Rem/Mod/Plus (overflow not possible, the check | |
423 | -- for zero-divide is a divide check, not an overflow check). | |
b8446e0d | 424 | |
c8e92b5f | 425 | if Nkind_In (N, N_Op_Rem, N_Op_Mod, N_Op_Plus) then |
426 | return; | |
427 | end if; | |
b8446e0d | 428 | end if; |
429 | ||
c8e92b5f | 430 | -- Fall through for cases where we do set the flag |
b8446e0d | 431 | |
432 | Set_Do_Overflow_Check (N, True); | |
433 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
00c403ee | 434 | end Activate_Overflow_Check; |
435 | ||
436 | -------------------------- | |
437 | -- Activate_Range_Check -- | |
438 | -------------------------- | |
439 | ||
440 | procedure Activate_Range_Check (N : Node_Id) is | |
441 | begin | |
442 | Set_Do_Range_Check (N, True); | |
443 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
444 | end Activate_Range_Check; | |
445 | ||
0577b0b1 | 446 | --------------------------------- |
447 | -- Alignment_Checks_Suppressed -- | |
448 | --------------------------------- | |
449 | ||
450 | function Alignment_Checks_Suppressed (E : Entity_Id) return Boolean is | |
451 | begin | |
452 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
453 | return Is_Check_Suppressed (E, Alignment_Check); | |
454 | else | |
fafc6b97 | 455 | return Scope_Suppress.Suppress (Alignment_Check); |
0577b0b1 | 456 | end if; |
457 | end Alignment_Checks_Suppressed; | |
458 | ||
2d70530c | 459 | ---------------------------------- |
460 | -- Allocation_Checks_Suppressed -- | |
461 | ---------------------------------- | |
462 | ||
fa771c05 | 463 | -- Note: at the current time there are no calls to this function, because |
464 | -- the relevant check is in the run-time, so it is not a check that the | |
465 | -- compiler can suppress anyway, but we still have to recognize the check | |
466 | -- name Allocation_Check since it is part of the standard. | |
467 | ||
2d70530c | 468 | function Allocation_Checks_Suppressed (E : Entity_Id) return Boolean is |
469 | begin | |
470 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
471 | return Is_Check_Suppressed (E, Allocation_Check); | |
472 | else | |
473 | return Scope_Suppress.Suppress (Allocation_Check); | |
474 | end if; | |
475 | end Allocation_Checks_Suppressed; | |
476 | ||
ee6ba406 | 477 | ------------------------- |
478 | -- Append_Range_Checks -- | |
479 | ------------------------- | |
480 | ||
481 | procedure Append_Range_Checks | |
482 | (Checks : Check_Result; | |
483 | Stmts : List_Id; | |
484 | Suppress_Typ : Entity_Id; | |
485 | Static_Sloc : Source_Ptr; | |
486 | Flag_Node : Node_Id) | |
487 | is | |
9dfe12ae | 488 | Internal_Flag_Node : constant Node_Id := Flag_Node; |
489 | Internal_Static_Sloc : constant Source_Ptr := Static_Sloc; | |
490 | ||
ee6ba406 | 491 | Checks_On : constant Boolean := |
b6341c67 | 492 | (not Index_Checks_Suppressed (Suppress_Typ)) |
493 | or else (not Range_Checks_Suppressed (Suppress_Typ)); | |
ee6ba406 | 494 | |
495 | begin | |
496 | -- For now we just return if Checks_On is false, however this should | |
497 | -- be enhanced to check for an always True value in the condition | |
498 | -- and to generate a compilation warning??? | |
499 | ||
500 | if not Checks_On then | |
501 | return; | |
502 | end if; | |
503 | ||
504 | for J in 1 .. 2 loop | |
505 | exit when No (Checks (J)); | |
506 | ||
507 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
508 | and then Present (Condition (Checks (J))) | |
509 | then | |
510 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
511 | Append_To (Stmts, Checks (J)); | |
512 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
513 | end if; | |
514 | ||
515 | else | |
516 | Append_To | |
f15731c4 | 517 | (Stmts, |
518 | Make_Raise_Constraint_Error (Internal_Static_Sloc, | |
519 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 520 | end if; |
521 | end loop; | |
522 | end Append_Range_Checks; | |
523 | ||
524 | ------------------------ | |
525 | -- Apply_Access_Check -- | |
526 | ------------------------ | |
527 | ||
528 | procedure Apply_Access_Check (N : Node_Id) is | |
529 | P : constant Node_Id := Prefix (N); | |
530 | ||
531 | begin | |
13dbf220 | 532 | -- We do not need checks if we are not generating code (i.e. the |
533 | -- expander is not active). This is not just an optimization, there | |
534 | -- are cases (e.g. with pragma Debug) where generating the checks | |
535 | -- can cause real trouble). | |
284faf8b | 536 | |
a33565dd | 537 | if not Expander_Active then |
13dbf220 | 538 | return; |
9dfe12ae | 539 | end if; |
ee6ba406 | 540 | |
84d0d4a5 | 541 | -- No check if short circuiting makes check unnecessary |
9dfe12ae | 542 | |
84d0d4a5 | 543 | if not Check_Needed (P, Access_Check) then |
544 | return; | |
ee6ba406 | 545 | end if; |
9dfe12ae | 546 | |
cc60bd16 | 547 | -- No check if accessing the Offset_To_Top component of a dispatch |
548 | -- table. They are safe by construction. | |
549 | ||
040277b1 | 550 | if Tagged_Type_Expansion |
551 | and then Present (Etype (P)) | |
cc60bd16 | 552 | and then RTU_Loaded (Ada_Tags) |
553 | and then RTE_Available (RE_Offset_To_Top_Ptr) | |
554 | and then Etype (P) = RTE (RE_Offset_To_Top_Ptr) | |
555 | then | |
556 | return; | |
557 | end if; | |
558 | ||
84d0d4a5 | 559 | -- Otherwise go ahead and install the check |
9dfe12ae | 560 | |
fa7497e8 | 561 | Install_Null_Excluding_Check (P); |
ee6ba406 | 562 | end Apply_Access_Check; |
563 | ||
564 | ------------------------------- | |
565 | -- Apply_Accessibility_Check -- | |
566 | ------------------------------- | |
567 | ||
55dc6dc2 | 568 | procedure Apply_Accessibility_Check |
569 | (N : Node_Id; | |
570 | Typ : Entity_Id; | |
571 | Insert_Node : Node_Id) | |
572 | is | |
ee6ba406 | 573 | Loc : constant Source_Ptr := Sloc (N); |
1a9cc6cd | 574 | Param_Ent : Entity_Id := Param_Entity (N); |
ee6ba406 | 575 | Param_Level : Node_Id; |
576 | Type_Level : Node_Id; | |
577 | ||
578 | begin | |
47d210a3 | 579 | if Ada_Version >= Ada_2012 |
580 | and then not Present (Param_Ent) | |
581 | and then Is_Entity_Name (N) | |
582 | and then Ekind_In (Entity (N), E_Constant, E_Variable) | |
583 | and then Present (Effective_Extra_Accessibility (Entity (N))) | |
584 | then | |
585 | Param_Ent := Entity (N); | |
586 | while Present (Renamed_Object (Param_Ent)) loop | |
1a9cc6cd | 587 | |
47d210a3 | 588 | -- Renamed_Object must return an Entity_Name here |
589 | -- because of preceding "Present (E_E_A (...))" test. | |
590 | ||
591 | Param_Ent := Entity (Renamed_Object (Param_Ent)); | |
592 | end loop; | |
593 | end if; | |
594 | ||
ee6ba406 | 595 | if Inside_A_Generic then |
596 | return; | |
597 | ||
6ffc64fc | 598 | -- Only apply the run-time check if the access parameter has an |
599 | -- associated extra access level parameter and when the level of the | |
600 | -- type is less deep than the level of the access parameter, and | |
601 | -- accessibility checks are not suppressed. | |
ee6ba406 | 602 | |
603 | elsif Present (Param_Ent) | |
604 | and then Present (Extra_Accessibility (Param_Ent)) | |
47d210a3 | 605 | and then UI_Gt (Object_Access_Level (N), |
1a9cc6cd | 606 | Deepest_Type_Access_Level (Typ)) |
ee6ba406 | 607 | and then not Accessibility_Checks_Suppressed (Param_Ent) |
608 | and then not Accessibility_Checks_Suppressed (Typ) | |
609 | then | |
610 | Param_Level := | |
611 | New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc); | |
612 | ||
1a9cc6cd | 613 | Type_Level := |
614 | Make_Integer_Literal (Loc, Deepest_Type_Access_Level (Typ)); | |
ee6ba406 | 615 | |
bf3e1520 | 616 | -- Raise Program_Error if the accessibility level of the access |
84d0d4a5 | 617 | -- parameter is deeper than the level of the target access type. |
ee6ba406 | 618 | |
55dc6dc2 | 619 | Insert_Action (Insert_Node, |
ee6ba406 | 620 | Make_Raise_Program_Error (Loc, |
621 | Condition => | |
622 | Make_Op_Gt (Loc, | |
623 | Left_Opnd => Param_Level, | |
f15731c4 | 624 | Right_Opnd => Type_Level), |
625 | Reason => PE_Accessibility_Check_Failed)); | |
ee6ba406 | 626 | |
627 | Analyze_And_Resolve (N); | |
628 | end if; | |
629 | end Apply_Accessibility_Check; | |
630 | ||
0577b0b1 | 631 | -------------------------------- |
632 | -- Apply_Address_Clause_Check -- | |
633 | -------------------------------- | |
634 | ||
635 | procedure Apply_Address_Clause_Check (E : Entity_Id; N : Node_Id) is | |
d950dc79 | 636 | pragma Assert (Nkind (N) = N_Freeze_Entity); |
637 | ||
0577b0b1 | 638 | AC : constant Node_Id := Address_Clause (E); |
639 | Loc : constant Source_Ptr := Sloc (AC); | |
640 | Typ : constant Entity_Id := Etype (E); | |
641 | Aexp : constant Node_Id := Expression (AC); | |
c2b56224 | 642 | |
c2b56224 | 643 | Expr : Node_Id; |
0577b0b1 | 644 | -- Address expression (not necessarily the same as Aexp, for example |
645 | -- when Aexp is a reference to a constant, in which case Expr gets | |
7b8fa048 | 646 | -- reset to reference the value expression of the constant). |
0577b0b1 | 647 | |
0577b0b1 | 648 | procedure Compile_Time_Bad_Alignment; |
649 | -- Post error warnings when alignment is known to be incompatible. Note | |
650 | -- that we do not go as far as inserting a raise of Program_Error since | |
651 | -- this is an erroneous case, and it may happen that we are lucky and an | |
d6da7448 | 652 | -- underaligned address turns out to be OK after all. |
0577b0b1 | 653 | |
654 | -------------------------------- | |
655 | -- Compile_Time_Bad_Alignment -- | |
656 | -------------------------------- | |
657 | ||
658 | procedure Compile_Time_Bad_Alignment is | |
659 | begin | |
d6da7448 | 660 | if Address_Clause_Overlay_Warnings then |
0577b0b1 | 661 | Error_Msg_FE |
cb97ae5c | 662 | ("?o?specified address for& may be inconsistent with alignment", |
0577b0b1 | 663 | Aexp, E); |
664 | Error_Msg_FE | |
cb97ae5c | 665 | ("\?o?program execution may be erroneous (RM 13.3(27))", |
0577b0b1 | 666 | Aexp, E); |
83f8f0a6 | 667 | Set_Address_Warning_Posted (AC); |
0577b0b1 | 668 | end if; |
669 | end Compile_Time_Bad_Alignment; | |
c2b56224 | 670 | |
2af58f67 | 671 | -- Start of processing for Apply_Address_Clause_Check |
5c61a0ff | 672 | |
c2b56224 | 673 | begin |
d6da7448 | 674 | -- See if alignment check needed. Note that we never need a check if the |
675 | -- maximum alignment is one, since the check will always succeed. | |
676 | ||
677 | -- Note: we do not check for checks suppressed here, since that check | |
678 | -- was done in Sem_Ch13 when the address clause was processed. We are | |
679 | -- only called if checks were not suppressed. The reason for this is | |
680 | -- that we have to delay the call to Apply_Alignment_Check till freeze | |
681 | -- time (so that all types etc are elaborated), but we have to check | |
682 | -- the status of check suppressing at the point of the address clause. | |
683 | ||
684 | if No (AC) | |
685 | or else not Check_Address_Alignment (AC) | |
686 | or else Maximum_Alignment = 1 | |
687 | then | |
688 | return; | |
689 | end if; | |
690 | ||
691 | -- Obtain expression from address clause | |
9dfe12ae | 692 | |
0577b0b1 | 693 | Expr := Expression (AC); |
694 | ||
695 | -- The following loop digs for the real expression to use in the check | |
696 | ||
697 | loop | |
698 | -- For constant, get constant expression | |
699 | ||
700 | if Is_Entity_Name (Expr) | |
701 | and then Ekind (Entity (Expr)) = E_Constant | |
702 | then | |
703 | Expr := Constant_Value (Entity (Expr)); | |
704 | ||
705 | -- For unchecked conversion, get result to convert | |
706 | ||
707 | elsif Nkind (Expr) = N_Unchecked_Type_Conversion then | |
708 | Expr := Expression (Expr); | |
709 | ||
710 | -- For (common case) of To_Address call, get argument | |
711 | ||
712 | elsif Nkind (Expr) = N_Function_Call | |
713 | and then Is_Entity_Name (Name (Expr)) | |
714 | and then Is_RTE (Entity (Name (Expr)), RE_To_Address) | |
715 | then | |
716 | Expr := First (Parameter_Associations (Expr)); | |
717 | ||
718 | if Nkind (Expr) = N_Parameter_Association then | |
719 | Expr := Explicit_Actual_Parameter (Expr); | |
720 | end if; | |
721 | ||
722 | -- We finally have the real expression | |
723 | ||
724 | else | |
725 | exit; | |
726 | end if; | |
727 | end loop; | |
728 | ||
d6da7448 | 729 | -- See if we know that Expr has a bad alignment at compile time |
c2b56224 | 730 | |
731 | if Compile_Time_Known_Value (Expr) | |
f2a06be9 | 732 | and then (Known_Alignment (E) or else Known_Alignment (Typ)) |
c2b56224 | 733 | then |
f2a06be9 | 734 | declare |
735 | AL : Uint := Alignment (Typ); | |
736 | ||
737 | begin | |
738 | -- The object alignment might be more restrictive than the | |
739 | -- type alignment. | |
740 | ||
741 | if Known_Alignment (E) then | |
742 | AL := Alignment (E); | |
743 | end if; | |
744 | ||
745 | if Expr_Value (Expr) mod AL /= 0 then | |
0577b0b1 | 746 | Compile_Time_Bad_Alignment; |
747 | else | |
748 | return; | |
f2a06be9 | 749 | end if; |
750 | end; | |
c2b56224 | 751 | |
0577b0b1 | 752 | -- If the expression has the form X'Address, then we can find out if |
753 | -- the object X has an alignment that is compatible with the object E. | |
d6da7448 | 754 | -- If it hasn't or we don't know, we defer issuing the warning until |
755 | -- the end of the compilation to take into account back end annotations. | |
c2b56224 | 756 | |
0577b0b1 | 757 | elsif Nkind (Expr) = N_Attribute_Reference |
758 | and then Attribute_Name (Expr) = Name_Address | |
d6da7448 | 759 | and then Has_Compatible_Alignment (E, Prefix (Expr)) = Known_Compatible |
0577b0b1 | 760 | then |
d6da7448 | 761 | return; |
0577b0b1 | 762 | end if; |
c2b56224 | 763 | |
6fb3c314 | 764 | -- Here we do not know if the value is acceptable. Strictly we don't |
765 | -- have to do anything, since if the alignment is bad, we have an | |
766 | -- erroneous program. However we are allowed to check for erroneous | |
767 | -- conditions and we decide to do this by default if the check is not | |
768 | -- suppressed. | |
0577b0b1 | 769 | |
770 | -- However, don't do the check if elaboration code is unwanted | |
771 | ||
772 | if Restriction_Active (No_Elaboration_Code) then | |
773 | return; | |
774 | ||
775 | -- Generate a check to raise PE if alignment may be inappropriate | |
776 | ||
777 | else | |
778 | -- If the original expression is a non-static constant, use the | |
779 | -- name of the constant itself rather than duplicating its | |
00c403ee | 780 | -- defining expression, which was extracted above. |
0577b0b1 | 781 | |
00c403ee | 782 | -- Note: Expr is empty if the address-clause is applied to in-mode |
783 | -- actuals (allowed by 13.1(22)). | |
784 | ||
785 | if not Present (Expr) | |
786 | or else | |
787 | (Is_Entity_Name (Expression (AC)) | |
788 | and then Ekind (Entity (Expression (AC))) = E_Constant | |
789 | and then Nkind (Parent (Entity (Expression (AC)))) | |
790 | = N_Object_Declaration) | |
0577b0b1 | 791 | then |
792 | Expr := New_Copy_Tree (Expression (AC)); | |
793 | else | |
794 | Remove_Side_Effects (Expr); | |
c2b56224 | 795 | end if; |
c2b56224 | 796 | |
d950dc79 | 797 | if No (Actions (N)) then |
798 | Set_Actions (N, New_List); | |
799 | end if; | |
800 | ||
801 | Prepend_To (Actions (N), | |
0577b0b1 | 802 | Make_Raise_Program_Error (Loc, |
803 | Condition => | |
804 | Make_Op_Ne (Loc, | |
805 | Left_Opnd => | |
806 | Make_Op_Mod (Loc, | |
807 | Left_Opnd => | |
808 | Unchecked_Convert_To | |
809 | (RTE (RE_Integer_Address), Expr), | |
810 | Right_Opnd => | |
811 | Make_Attribute_Reference (Loc, | |
d950dc79 | 812 | Prefix => New_Occurrence_Of (E, Loc), |
0577b0b1 | 813 | Attribute_Name => Name_Alignment)), |
814 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
7b8fa048 | 815 | Reason => PE_Misaligned_Address_Value)); |
816 | ||
817 | Warning_Msg := No_Error_Msg; | |
d950dc79 | 818 | Analyze (First (Actions (N)), Suppress => All_Checks); |
cd309f05 | 819 | |
7b8fa048 | 820 | -- If the address clause generated a warning message (for example, |
821 | -- from Warn_On_Non_Local_Exception mode with the active restriction | |
822 | -- No_Exception_Propagation). | |
823 | ||
824 | if Warning_Msg /= No_Error_Msg then | |
825 | ||
826 | -- If the expression has a known at compile time value, then | |
827 | -- once we know the alignment of the type, we can check if the | |
828 | -- exception will be raised or not, and if not, we don't need | |
829 | -- the warning so we will kill the warning later on. | |
830 | ||
831 | if Compile_Time_Known_Value (Expr) then | |
832 | Alignment_Warnings.Append | |
833 | ((E => E, A => Expr_Value (Expr), W => Warning_Msg)); | |
834 | end if; | |
835 | ||
836 | -- Add explanation of the warning that is generated by the check | |
cd309f05 | 837 | |
78be29d1 | 838 | Error_Msg_N |
7b8fa048 | 839 | ("\address value may be incompatible with alignment " |
840 | & "of object?X?", AC); | |
cd309f05 | 841 | end if; |
78be29d1 | 842 | |
0577b0b1 | 843 | return; |
844 | end if; | |
9dfe12ae | 845 | |
846 | exception | |
0577b0b1 | 847 | -- If we have some missing run time component in configurable run time |
848 | -- mode then just skip the check (it is not required in any case). | |
849 | ||
9dfe12ae | 850 | when RE_Not_Available => |
851 | return; | |
0577b0b1 | 852 | end Apply_Address_Clause_Check; |
c2b56224 | 853 | |
ee6ba406 | 854 | ------------------------------------- |
855 | -- Apply_Arithmetic_Overflow_Check -- | |
856 | ------------------------------------- | |
857 | ||
3cce7f32 | 858 | procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is |
859 | begin | |
860 | -- Use old routine in almost all cases (the only case we are treating | |
21a55437 | 861 | -- specially is the case of a signed integer arithmetic op with the |
0df9d43f | 862 | -- overflow checking mode set to MINIMIZED or ELIMINATED). |
3cce7f32 | 863 | |
0df9d43f | 864 | if Overflow_Check_Mode = Strict |
3cce7f32 | 865 | or else not Is_Signed_Integer_Arithmetic_Op (N) |
866 | then | |
0df9d43f | 867 | Apply_Arithmetic_Overflow_Strict (N); |
3cce7f32 | 868 | |
21a55437 | 869 | -- Otherwise use the new routine for the case of a signed integer |
870 | -- arithmetic op, with Do_Overflow_Check set to True, and the checking | |
871 | -- mode is MINIMIZED or ELIMINATED. | |
3cce7f32 | 872 | |
873 | else | |
874 | Apply_Arithmetic_Overflow_Minimized_Eliminated (N); | |
875 | end if; | |
876 | end Apply_Arithmetic_Overflow_Check; | |
877 | ||
0df9d43f | 878 | -------------------------------------- |
879 | -- Apply_Arithmetic_Overflow_Strict -- | |
880 | -------------------------------------- | |
3cce7f32 | 881 | |
f40f9731 | 882 | -- This routine is called only if the type is an integer type, and a |
883 | -- software arithmetic overflow check may be needed for op (add, subtract, | |
884 | -- or multiply). This check is performed only if Software_Overflow_Checking | |
885 | -- is enabled and Do_Overflow_Check is set. In this case we expand the | |
886 | -- operation into a more complex sequence of tests that ensures that | |
887 | -- overflow is properly caught. | |
ee6ba406 | 888 | |
0df9d43f | 889 | -- This is used in CHECKED modes. It is identical to the code for this |
890 | -- cases before the big overflow earthquake, thus ensuring that in this | |
891 | -- modes we have compatible behavior (and reliability) to what was there | |
892 | -- before. It is also called for types other than signed integers, and if | |
893 | -- the Do_Overflow_Check flag is off. | |
3cce7f32 | 894 | |
895 | -- Note: we also call this routine if we decide in the MINIMIZED case | |
896 | -- to give up and just generate an overflow check without any fuss. | |
897 | ||
0df9d43f | 898 | procedure Apply_Arithmetic_Overflow_Strict (N : Node_Id) is |
21a55437 | 899 | Loc : constant Source_Ptr := Sloc (N); |
900 | Typ : constant Entity_Id := Etype (N); | |
901 | Rtyp : constant Entity_Id := Root_Type (Typ); | |
ee6ba406 | 902 | |
903 | begin | |
0df9d43f | 904 | -- Nothing to do if Do_Overflow_Check not set or overflow checks |
905 | -- suppressed. | |
906 | ||
907 | if not Do_Overflow_Check (N) then | |
908 | return; | |
909 | end if; | |
910 | ||
f40f9731 | 911 | -- An interesting special case. If the arithmetic operation appears as |
912 | -- the operand of a type conversion: | |
913 | ||
914 | -- type1 (x op y) | |
915 | ||
916 | -- and all the following conditions apply: | |
917 | ||
918 | -- arithmetic operation is for a signed integer type | |
919 | -- target type type1 is a static integer subtype | |
920 | -- range of x and y are both included in the range of type1 | |
921 | -- range of x op y is included in the range of type1 | |
922 | -- size of type1 is at least twice the result size of op | |
923 | ||
924 | -- then we don't do an overflow check in any case, instead we transform | |
925 | -- the operation so that we end up with: | |
926 | ||
927 | -- type1 (type1 (x) op type1 (y)) | |
928 | ||
929 | -- This avoids intermediate overflow before the conversion. It is | |
930 | -- explicitly permitted by RM 3.5.4(24): | |
931 | ||
932 | -- For the execution of a predefined operation of a signed integer | |
933 | -- type, the implementation need not raise Constraint_Error if the | |
934 | -- result is outside the base range of the type, so long as the | |
935 | -- correct result is produced. | |
936 | ||
937 | -- It's hard to imagine that any programmer counts on the exception | |
938 | -- being raised in this case, and in any case it's wrong coding to | |
939 | -- have this expectation, given the RM permission. Furthermore, other | |
940 | -- Ada compilers do allow such out of range results. | |
941 | ||
942 | -- Note that we do this transformation even if overflow checking is | |
943 | -- off, since this is precisely about giving the "right" result and | |
944 | -- avoiding the need for an overflow check. | |
945 | ||
8eb4a5eb | 946 | -- Note: this circuit is partially redundant with respect to the similar |
947 | -- processing in Exp_Ch4.Expand_N_Type_Conversion, but the latter deals | |
948 | -- with cases that do not come through here. We still need the following | |
949 | -- processing even with the Exp_Ch4 code in place, since we want to be | |
950 | -- sure not to generate the arithmetic overflow check in these cases | |
951 | -- (Exp_Ch4 would have a hard time removing them once generated). | |
952 | ||
f40f9731 | 953 | if Is_Signed_Integer_Type (Typ) |
954 | and then Nkind (Parent (N)) = N_Type_Conversion | |
ee6ba406 | 955 | then |
f32c377d | 956 | Conversion_Optimization : declare |
f40f9731 | 957 | Target_Type : constant Entity_Id := |
b6341c67 | 958 | Base_Type (Entity (Subtype_Mark (Parent (N)))); |
f40f9731 | 959 | |
960 | Llo, Lhi : Uint; | |
961 | Rlo, Rhi : Uint; | |
962 | LOK, ROK : Boolean; | |
963 | ||
964 | Vlo : Uint; | |
965 | Vhi : Uint; | |
966 | VOK : Boolean; | |
967 | ||
968 | Tlo : Uint; | |
969 | Thi : Uint; | |
970 | ||
971 | begin | |
972 | if Is_Integer_Type (Target_Type) | |
973 | and then RM_Size (Root_Type (Target_Type)) >= 2 * RM_Size (Rtyp) | |
974 | then | |
975 | Tlo := Expr_Value (Type_Low_Bound (Target_Type)); | |
976 | Thi := Expr_Value (Type_High_Bound (Target_Type)); | |
977 | ||
9c486805 | 978 | Determine_Range |
979 | (Left_Opnd (N), LOK, Llo, Lhi, Assume_Valid => True); | |
980 | Determine_Range | |
981 | (Right_Opnd (N), ROK, Rlo, Rhi, Assume_Valid => True); | |
f40f9731 | 982 | |
983 | if (LOK and ROK) | |
984 | and then Tlo <= Llo and then Lhi <= Thi | |
985 | and then Tlo <= Rlo and then Rhi <= Thi | |
986 | then | |
9c486805 | 987 | Determine_Range (N, VOK, Vlo, Vhi, Assume_Valid => True); |
f40f9731 | 988 | |
989 | if VOK and then Tlo <= Vlo and then Vhi <= Thi then | |
990 | Rewrite (Left_Opnd (N), | |
991 | Make_Type_Conversion (Loc, | |
992 | Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), | |
993 | Expression => Relocate_Node (Left_Opnd (N)))); | |
994 | ||
995 | Rewrite (Right_Opnd (N), | |
996 | Make_Type_Conversion (Loc, | |
997 | Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), | |
998 | Expression => Relocate_Node (Right_Opnd (N)))); | |
999 | ||
780bfb21 | 1000 | -- Rewrite the conversion operand so that the original |
1001 | -- node is retained, in order to avoid the warning for | |
1002 | -- redundant conversions in Resolve_Type_Conversion. | |
1003 | ||
1004 | Rewrite (N, Relocate_Node (N)); | |
1005 | ||
f40f9731 | 1006 | Set_Etype (N, Target_Type); |
780bfb21 | 1007 | |
f40f9731 | 1008 | Analyze_And_Resolve (Left_Opnd (N), Target_Type); |
1009 | Analyze_And_Resolve (Right_Opnd (N), Target_Type); | |
1010 | ||
1011 | -- Given that the target type is twice the size of the | |
1012 | -- source type, overflow is now impossible, so we can | |
1013 | -- safely kill the overflow check and return. | |
1014 | ||
1015 | Set_Do_Overflow_Check (N, False); | |
1016 | return; | |
1017 | end if; | |
1018 | end if; | |
1019 | end if; | |
f32c377d | 1020 | end Conversion_Optimization; |
ee6ba406 | 1021 | end if; |
1022 | ||
f40f9731 | 1023 | -- Now see if an overflow check is required |
1024 | ||
1025 | declare | |
1026 | Siz : constant Int := UI_To_Int (Esize (Rtyp)); | |
1027 | Dsiz : constant Int := Siz * 2; | |
1028 | Opnod : Node_Id; | |
1029 | Ctyp : Entity_Id; | |
1030 | Opnd : Node_Id; | |
1031 | Cent : RE_Id; | |
ee6ba406 | 1032 | |
f40f9731 | 1033 | begin |
1034 | -- Skip check if back end does overflow checks, or the overflow flag | |
df40eeb0 | 1035 | -- is not set anyway, or we are not doing code expansion, or the |
1036 | -- parent node is a type conversion whose operand is an arithmetic | |
1037 | -- operation on signed integers on which the expander can promote | |
bbbed24b | 1038 | -- later the operands to type Integer (see Expand_N_Type_Conversion). |
ee6ba406 | 1039 | |
f40f9731 | 1040 | -- Special case CLI target, where arithmetic overflow checks can be |
1041 | -- performed for integer and long_integer | |
ee6ba406 | 1042 | |
f40f9731 | 1043 | if Backend_Overflow_Checks_On_Target |
1044 | or else not Do_Overflow_Check (N) | |
a33565dd | 1045 | or else not Expander_Active |
df40eeb0 | 1046 | or else (Present (Parent (N)) |
1047 | and then Nkind (Parent (N)) = N_Type_Conversion | |
1048 | and then Integer_Promotion_Possible (Parent (N))) | |
f40f9731 | 1049 | or else |
1050 | (VM_Target = CLI_Target and then Siz >= Standard_Integer_Size) | |
1051 | then | |
1052 | return; | |
1053 | end if; | |
ee6ba406 | 1054 | |
f40f9731 | 1055 | -- Otherwise, generate the full general code for front end overflow |
1056 | -- detection, which works by doing arithmetic in a larger type: | |
ee6ba406 | 1057 | |
f40f9731 | 1058 | -- x op y |
ee6ba406 | 1059 | |
f40f9731 | 1060 | -- is expanded into |
ee6ba406 | 1061 | |
f40f9731 | 1062 | -- Typ (Checktyp (x) op Checktyp (y)); |
ee6ba406 | 1063 | |
f40f9731 | 1064 | -- where Typ is the type of the original expression, and Checktyp is |
1065 | -- an integer type of sufficient length to hold the largest possible | |
1066 | -- result. | |
ee6ba406 | 1067 | |
f40f9731 | 1068 | -- If the size of check type exceeds the size of Long_Long_Integer, |
1069 | -- we use a different approach, expanding to: | |
ee6ba406 | 1070 | |
f40f9731 | 1071 | -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y))) |
ee6ba406 | 1072 | |
f40f9731 | 1073 | -- where xxx is Add, Multiply or Subtract as appropriate |
ee6ba406 | 1074 | |
f40f9731 | 1075 | -- Find check type if one exists |
1076 | ||
1077 | if Dsiz <= Standard_Integer_Size then | |
1078 | Ctyp := Standard_Integer; | |
ee6ba406 | 1079 | |
f40f9731 | 1080 | elsif Dsiz <= Standard_Long_Long_Integer_Size then |
1081 | Ctyp := Standard_Long_Long_Integer; | |
1082 | ||
c9f84db7 | 1083 | -- No check type exists, use runtime call |
ee6ba406 | 1084 | |
1085 | else | |
f40f9731 | 1086 | if Nkind (N) = N_Op_Add then |
1087 | Cent := RE_Add_With_Ovflo_Check; | |
ee6ba406 | 1088 | |
f40f9731 | 1089 | elsif Nkind (N) = N_Op_Multiply then |
1090 | Cent := RE_Multiply_With_Ovflo_Check; | |
ee6ba406 | 1091 | |
f40f9731 | 1092 | else |
1093 | pragma Assert (Nkind (N) = N_Op_Subtract); | |
1094 | Cent := RE_Subtract_With_Ovflo_Check; | |
1095 | end if; | |
1096 | ||
1097 | Rewrite (N, | |
1098 | OK_Convert_To (Typ, | |
1099 | Make_Function_Call (Loc, | |
83c6c069 | 1100 | Name => New_Occurrence_Of (RTE (Cent), Loc), |
f40f9731 | 1101 | Parameter_Associations => New_List ( |
1102 | OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)), | |
1103 | OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N)))))); | |
ee6ba406 | 1104 | |
f40f9731 | 1105 | Analyze_And_Resolve (N, Typ); |
1106 | return; | |
1107 | end if; | |
ee6ba406 | 1108 | |
f40f9731 | 1109 | -- If we fall through, we have the case where we do the arithmetic |
1110 | -- in the next higher type and get the check by conversion. In these | |
1111 | -- cases Ctyp is set to the type to be used as the check type. | |
ee6ba406 | 1112 | |
f40f9731 | 1113 | Opnod := Relocate_Node (N); |
ee6ba406 | 1114 | |
f40f9731 | 1115 | Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod)); |
ee6ba406 | 1116 | |
f40f9731 | 1117 | Analyze (Opnd); |
1118 | Set_Etype (Opnd, Ctyp); | |
1119 | Set_Analyzed (Opnd, True); | |
1120 | Set_Left_Opnd (Opnod, Opnd); | |
ee6ba406 | 1121 | |
f40f9731 | 1122 | Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod)); |
ee6ba406 | 1123 | |
f40f9731 | 1124 | Analyze (Opnd); |
1125 | Set_Etype (Opnd, Ctyp); | |
1126 | Set_Analyzed (Opnd, True); | |
1127 | Set_Right_Opnd (Opnod, Opnd); | |
ee6ba406 | 1128 | |
f40f9731 | 1129 | -- The type of the operation changes to the base type of the check |
1130 | -- type, and we reset the overflow check indication, since clearly no | |
1131 | -- overflow is possible now that we are using a double length type. | |
1132 | -- We also set the Analyzed flag to avoid a recursive attempt to | |
1133 | -- expand the node. | |
ee6ba406 | 1134 | |
f40f9731 | 1135 | Set_Etype (Opnod, Base_Type (Ctyp)); |
1136 | Set_Do_Overflow_Check (Opnod, False); | |
1137 | Set_Analyzed (Opnod, True); | |
ee6ba406 | 1138 | |
f40f9731 | 1139 | -- Now build the outer conversion |
ee6ba406 | 1140 | |
f40f9731 | 1141 | Opnd := OK_Convert_To (Typ, Opnod); |
1142 | Analyze (Opnd); | |
1143 | Set_Etype (Opnd, Typ); | |
9dfe12ae | 1144 | |
f40f9731 | 1145 | -- In the discrete type case, we directly generate the range check |
1146 | -- for the outer operand. This range check will implement the | |
1147 | -- required overflow check. | |
9dfe12ae | 1148 | |
f40f9731 | 1149 | if Is_Discrete_Type (Typ) then |
1150 | Rewrite (N, Opnd); | |
1151 | Generate_Range_Check | |
1152 | (Expression (N), Typ, CE_Overflow_Check_Failed); | |
9dfe12ae | 1153 | |
f40f9731 | 1154 | -- For other types, we enable overflow checking on the conversion, |
1155 | -- after setting the node as analyzed to prevent recursive attempts | |
1156 | -- to expand the conversion node. | |
9dfe12ae | 1157 | |
f40f9731 | 1158 | else |
1159 | Set_Analyzed (Opnd, True); | |
1160 | Enable_Overflow_Check (Opnd); | |
1161 | Rewrite (N, Opnd); | |
1162 | end if; | |
1163 | ||
1164 | exception | |
1165 | when RE_Not_Available => | |
1166 | return; | |
1167 | end; | |
0df9d43f | 1168 | end Apply_Arithmetic_Overflow_Strict; |
3cce7f32 | 1169 | |
1170 | ---------------------------------------------------- | |
1171 | -- Apply_Arithmetic_Overflow_Minimized_Eliminated -- | |
1172 | ---------------------------------------------------- | |
1173 | ||
1174 | procedure Apply_Arithmetic_Overflow_Minimized_Eliminated (Op : Node_Id) is | |
1175 | pragma Assert (Is_Signed_Integer_Arithmetic_Op (Op)); | |
3cce7f32 | 1176 | |
1177 | Loc : constant Source_Ptr := Sloc (Op); | |
1178 | P : constant Node_Id := Parent (Op); | |
1179 | ||
49b3a812 | 1180 | LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); |
1181 | -- Operands and results are of this type when we convert | |
1182 | ||
3cce7f32 | 1183 | Result_Type : constant Entity_Id := Etype (Op); |
1184 | -- Original result type | |
1185 | ||
db415383 | 1186 | Check_Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
3cce7f32 | 1187 | pragma Assert (Check_Mode in Minimized_Or_Eliminated); |
1188 | ||
1189 | Lo, Hi : Uint; | |
1190 | -- Ranges of values for result | |
1191 | ||
1192 | begin | |
1193 | -- Nothing to do if our parent is one of the following: | |
1194 | ||
0326b4d4 | 1195 | -- Another signed integer arithmetic op |
3cce7f32 | 1196 | -- A membership operation |
1197 | -- A comparison operation | |
1198 | ||
1199 | -- In all these cases, we will process at the higher level (and then | |
1200 | -- this node will be processed during the downwards recursion that | |
0df9d43f | 1201 | -- is part of the processing in Minimize_Eliminate_Overflows). |
3cce7f32 | 1202 | |
1203 | if Is_Signed_Integer_Arithmetic_Op (P) | |
b8a17a21 | 1204 | or else Nkind (P) in N_Membership_Test |
1205 | or else Nkind (P) in N_Op_Compare | |
aa4b16cb | 1206 | |
70a2dff4 | 1207 | -- This is also true for an alternative in a case expression |
1208 | ||
1209 | or else Nkind (P) = N_Case_Expression_Alternative | |
1210 | ||
1211 | -- This is also true for a range operand in a membership test | |
aa4b16cb | 1212 | |
b8a17a21 | 1213 | or else (Nkind (P) = N_Range |
1214 | and then Nkind (Parent (P)) in N_Membership_Test) | |
3cce7f32 | 1215 | then |
1216 | return; | |
1217 | end if; | |
1218 | ||
0326b4d4 | 1219 | -- Otherwise, we have a top level arithmetic operation node, and this |
21a55437 | 1220 | -- is where we commence the special processing for MINIMIZED/ELIMINATED |
1221 | -- modes. This is the case where we tell the machinery not to move into | |
1222 | -- Bignum mode at this top level (of course the top level operation | |
1223 | -- will still be in Bignum mode if either of its operands are of type | |
1224 | -- Bignum). | |
3cce7f32 | 1225 | |
0df9d43f | 1226 | Minimize_Eliminate_Overflows (Op, Lo, Hi, Top_Level => True); |
3cce7f32 | 1227 | |
1228 | -- That call may but does not necessarily change the result type of Op. | |
1229 | -- It is the job of this routine to undo such changes, so that at the | |
1230 | -- top level, we have the proper type. This "undoing" is a point at | |
1231 | -- which a final overflow check may be applied. | |
1232 | ||
f32c377d | 1233 | -- If the result type was not fiddled we are all set. We go to base |
1234 | -- types here because things may have been rewritten to generate the | |
1235 | -- base type of the operand types. | |
3cce7f32 | 1236 | |
f32c377d | 1237 | if Base_Type (Etype (Op)) = Base_Type (Result_Type) then |
3cce7f32 | 1238 | return; |
1239 | ||
1240 | -- Bignum case | |
1241 | ||
49b3a812 | 1242 | elsif Is_RTE (Etype (Op), RE_Bignum) then |
3cce7f32 | 1243 | |
d94b5da2 | 1244 | -- We need a sequence that looks like: |
3cce7f32 | 1245 | |
1246 | -- Rnn : Result_Type; | |
1247 | ||
1248 | -- declare | |
d94b5da2 | 1249 | -- M : Mark_Id := SS_Mark; |
3cce7f32 | 1250 | -- begin |
49b3a812 | 1251 | -- Rnn := Long_Long_Integer'Base (From_Bignum (Op)); |
3cce7f32 | 1252 | -- SS_Release (M); |
1253 | -- end; | |
1254 | ||
1255 | -- This block is inserted (using Insert_Actions), and then the node | |
1256 | -- is replaced with a reference to Rnn. | |
1257 | ||
1258 | -- A special case arises if our parent is a conversion node. In this | |
1259 | -- case no point in generating a conversion to Result_Type, we will | |
1260 | -- let the parent handle this. Note that this special case is not | |
1261 | -- just about optimization. Consider | |
1262 | ||
1263 | -- A,B,C : Integer; | |
1264 | -- ... | |
49b3a812 | 1265 | -- X := Long_Long_Integer'Base (A * (B ** C)); |
3cce7f32 | 1266 | |
1267 | -- Now the product may fit in Long_Long_Integer but not in Integer. | |
21a55437 | 1268 | -- In MINIMIZED/ELIMINATED mode, we don't want to introduce an |
1269 | -- overflow exception for this intermediate value. | |
3cce7f32 | 1270 | |
1271 | declare | |
49b3a812 | 1272 | Blk : constant Node_Id := Make_Bignum_Block (Loc); |
3cce7f32 | 1273 | Rnn : constant Entity_Id := Make_Temporary (Loc, 'R', Op); |
1274 | RHS : Node_Id; | |
1275 | ||
1276 | Rtype : Entity_Id; | |
1277 | ||
1278 | begin | |
1279 | RHS := Convert_From_Bignum (Op); | |
1280 | ||
1281 | if Nkind (P) /= N_Type_Conversion then | |
49b3a812 | 1282 | Convert_To_And_Rewrite (Result_Type, RHS); |
3cce7f32 | 1283 | Rtype := Result_Type; |
1284 | ||
1285 | -- Interesting question, do we need a check on that conversion | |
1286 | -- operation. Answer, not if we know the result is in range. | |
1287 | -- At the moment we are not taking advantage of this. To be | |
1288 | -- looked at later ??? | |
1289 | ||
1290 | else | |
49b3a812 | 1291 | Rtype := LLIB; |
3cce7f32 | 1292 | end if; |
1293 | ||
1294 | Insert_Before | |
1295 | (First (Statements (Handled_Statement_Sequence (Blk))), | |
1296 | Make_Assignment_Statement (Loc, | |
1297 | Name => New_Occurrence_Of (Rnn, Loc), | |
1298 | Expression => RHS)); | |
1299 | ||
1300 | Insert_Actions (Op, New_List ( | |
1301 | Make_Object_Declaration (Loc, | |
1302 | Defining_Identifier => Rnn, | |
1303 | Object_Definition => New_Occurrence_Of (Rtype, Loc)), | |
1304 | Blk)); | |
1305 | ||
1306 | Rewrite (Op, New_Occurrence_Of (Rnn, Loc)); | |
1307 | Analyze_And_Resolve (Op); | |
1308 | end; | |
1309 | ||
412f75eb | 1310 | -- Here we know the result is Long_Long_Integer'Base, of that it has |
1311 | -- been rewritten because the parent operation is a conversion. See | |
0df9d43f | 1312 | -- Apply_Arithmetic_Overflow_Strict.Conversion_Optimization. |
3cce7f32 | 1313 | |
1314 | else | |
f32c377d | 1315 | pragma Assert |
1316 | (Etype (Op) = LLIB or else Nkind (Parent (Op)) = N_Type_Conversion); | |
3cce7f32 | 1317 | |
1318 | -- All we need to do here is to convert the result to the proper | |
1319 | -- result type. As explained above for the Bignum case, we can | |
1320 | -- omit this if our parent is a type conversion. | |
1321 | ||
1322 | if Nkind (P) /= N_Type_Conversion then | |
1323 | Convert_To_And_Rewrite (Result_Type, Op); | |
1324 | end if; | |
1325 | ||
1326 | Analyze_And_Resolve (Op); | |
1327 | end if; | |
1328 | end Apply_Arithmetic_Overflow_Minimized_Eliminated; | |
ee6ba406 | 1329 | |
ee6ba406 | 1330 | ---------------------------- |
1331 | -- Apply_Constraint_Check -- | |
1332 | ---------------------------- | |
1333 | ||
1334 | procedure Apply_Constraint_Check | |
1335 | (N : Node_Id; | |
1336 | Typ : Entity_Id; | |
1337 | No_Sliding : Boolean := False) | |
1338 | is | |
1339 | Desig_Typ : Entity_Id; | |
1340 | ||
1341 | begin | |
7aafae1c | 1342 | -- No checks inside a generic (check the instantiations) |
1343 | ||
ee6ba406 | 1344 | if Inside_A_Generic then |
1345 | return; | |
7aafae1c | 1346 | end if; |
ee6ba406 | 1347 | |
6fb3c314 | 1348 | -- Apply required constraint checks |
7aafae1c | 1349 | |
1350 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 1351 | Apply_Scalar_Range_Check (N, Typ); |
1352 | ||
1353 | elsif Is_Array_Type (Typ) then | |
1354 | ||
05fcfafb | 1355 | -- A useful optimization: an aggregate with only an others clause |
5f260d20 | 1356 | -- always has the right bounds. |
1357 | ||
1358 | if Nkind (N) = N_Aggregate | |
1359 | and then No (Expressions (N)) | |
1360 | and then Nkind | |
1361 | (First (Choices (First (Component_Associations (N))))) | |
1362 | = N_Others_Choice | |
1363 | then | |
1364 | return; | |
1365 | end if; | |
1366 | ||
ee6ba406 | 1367 | if Is_Constrained (Typ) then |
1368 | Apply_Length_Check (N, Typ); | |
1369 | ||
1370 | if No_Sliding then | |
1371 | Apply_Range_Check (N, Typ); | |
1372 | end if; | |
1373 | else | |
1374 | Apply_Range_Check (N, Typ); | |
1375 | end if; | |
1376 | ||
4fb5f0a0 | 1377 | elsif (Is_Record_Type (Typ) or else Is_Private_Type (Typ)) |
ee6ba406 | 1378 | and then Has_Discriminants (Base_Type (Typ)) |
1379 | and then Is_Constrained (Typ) | |
1380 | then | |
1381 | Apply_Discriminant_Check (N, Typ); | |
1382 | ||
1383 | elsif Is_Access_Type (Typ) then | |
1384 | ||
1385 | Desig_Typ := Designated_Type (Typ); | |
1386 | ||
1387 | -- No checks necessary if expression statically null | |
1388 | ||
2af58f67 | 1389 | if Known_Null (N) then |
00c403ee | 1390 | if Can_Never_Be_Null (Typ) then |
1391 | Install_Null_Excluding_Check (N); | |
1392 | end if; | |
ee6ba406 | 1393 | |
1394 | -- No sliding possible on access to arrays | |
1395 | ||
1396 | elsif Is_Array_Type (Desig_Typ) then | |
1397 | if Is_Constrained (Desig_Typ) then | |
1398 | Apply_Length_Check (N, Typ); | |
1399 | end if; | |
1400 | ||
1401 | Apply_Range_Check (N, Typ); | |
1402 | ||
1403 | elsif Has_Discriminants (Base_Type (Desig_Typ)) | |
1404 | and then Is_Constrained (Desig_Typ) | |
1405 | then | |
1406 | Apply_Discriminant_Check (N, Typ); | |
1407 | end if; | |
fa7497e8 | 1408 | |
bf3e1520 | 1409 | -- Apply the 2005 Null_Excluding check. Note that we do not apply |
00c403ee | 1410 | -- this check if the constraint node is illegal, as shown by having |
1411 | -- an error posted. This additional guard prevents cascaded errors | |
1412 | -- and compiler aborts on illegal programs involving Ada 2005 checks. | |
1413 | ||
fa7497e8 | 1414 | if Can_Never_Be_Null (Typ) |
1415 | and then not Can_Never_Be_Null (Etype (N)) | |
00c403ee | 1416 | and then not Error_Posted (N) |
fa7497e8 | 1417 | then |
1418 | Install_Null_Excluding_Check (N); | |
1419 | end if; | |
ee6ba406 | 1420 | end if; |
1421 | end Apply_Constraint_Check; | |
1422 | ||
1423 | ------------------------------ | |
1424 | -- Apply_Discriminant_Check -- | |
1425 | ------------------------------ | |
1426 | ||
1427 | procedure Apply_Discriminant_Check | |
1428 | (N : Node_Id; | |
1429 | Typ : Entity_Id; | |
1430 | Lhs : Node_Id := Empty) | |
1431 | is | |
1432 | Loc : constant Source_Ptr := Sloc (N); | |
1433 | Do_Access : constant Boolean := Is_Access_Type (Typ); | |
1434 | S_Typ : Entity_Id := Etype (N); | |
1435 | Cond : Node_Id; | |
1436 | T_Typ : Entity_Id; | |
1437 | ||
7be5088a | 1438 | function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean; |
1439 | -- A heap object with an indefinite subtype is constrained by its | |
1440 | -- initial value, and assigning to it requires a constraint_check. | |
1441 | -- The target may be an explicit dereference, or a renaming of one. | |
1442 | ||
ee6ba406 | 1443 | function Is_Aliased_Unconstrained_Component return Boolean; |
1444 | -- It is possible for an aliased component to have a nominal | |
1445 | -- unconstrained subtype (through instantiation). If this is a | |
1446 | -- discriminated component assigned in the expansion of an aggregate | |
1447 | -- in an initialization, the check must be suppressed. This unusual | |
2af58f67 | 1448 | -- situation requires a predicate of its own. |
ee6ba406 | 1449 | |
7be5088a | 1450 | ---------------------------------- |
1451 | -- Denotes_Explicit_Dereference -- | |
1452 | ---------------------------------- | |
1453 | ||
1454 | function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean is | |
1455 | begin | |
1456 | return | |
1457 | Nkind (Obj) = N_Explicit_Dereference | |
1458 | or else | |
1459 | (Is_Entity_Name (Obj) | |
1460 | and then Present (Renamed_Object (Entity (Obj))) | |
9474aa9c | 1461 | and then Nkind (Renamed_Object (Entity (Obj))) = |
1462 | N_Explicit_Dereference); | |
7be5088a | 1463 | end Denotes_Explicit_Dereference; |
1464 | ||
ee6ba406 | 1465 | ---------------------------------------- |
1466 | -- Is_Aliased_Unconstrained_Component -- | |
1467 | ---------------------------------------- | |
1468 | ||
1469 | function Is_Aliased_Unconstrained_Component return Boolean is | |
1470 | Comp : Entity_Id; | |
1471 | Pref : Node_Id; | |
1472 | ||
1473 | begin | |
1474 | if Nkind (Lhs) /= N_Selected_Component then | |
1475 | return False; | |
1476 | else | |
1477 | Comp := Entity (Selector_Name (Lhs)); | |
1478 | Pref := Prefix (Lhs); | |
1479 | end if; | |
1480 | ||
1481 | if Ekind (Comp) /= E_Component | |
1482 | or else not Is_Aliased (Comp) | |
1483 | then | |
1484 | return False; | |
1485 | end if; | |
1486 | ||
1487 | return not Comes_From_Source (Pref) | |
1488 | and then In_Instance | |
1489 | and then not Is_Constrained (Etype (Comp)); | |
1490 | end Is_Aliased_Unconstrained_Component; | |
1491 | ||
1492 | -- Start of processing for Apply_Discriminant_Check | |
1493 | ||
1494 | begin | |
1495 | if Do_Access then | |
1496 | T_Typ := Designated_Type (Typ); | |
1497 | else | |
1498 | T_Typ := Typ; | |
1499 | end if; | |
1500 | ||
1501 | -- Nothing to do if discriminant checks are suppressed or else no code | |
1502 | -- is to be generated | |
1503 | ||
a33565dd | 1504 | if not Expander_Active |
ee6ba406 | 1505 | or else Discriminant_Checks_Suppressed (T_Typ) |
1506 | then | |
1507 | return; | |
1508 | end if; | |
1509 | ||
feff2f05 | 1510 | -- No discriminant checks necessary for an access when expression is |
1511 | -- statically Null. This is not only an optimization, it is fundamental | |
1512 | -- because otherwise discriminant checks may be generated in init procs | |
1513 | -- for types containing an access to a not-yet-frozen record, causing a | |
1514 | -- deadly forward reference. | |
ee6ba406 | 1515 | |
feff2f05 | 1516 | -- Also, if the expression is of an access type whose designated type is |
1517 | -- incomplete, then the access value must be null and we suppress the | |
1518 | -- check. | |
ee6ba406 | 1519 | |
2af58f67 | 1520 | if Known_Null (N) then |
ee6ba406 | 1521 | return; |
1522 | ||
1523 | elsif Is_Access_Type (S_Typ) then | |
1524 | S_Typ := Designated_Type (S_Typ); | |
1525 | ||
1526 | if Ekind (S_Typ) = E_Incomplete_Type then | |
1527 | return; | |
1528 | end if; | |
1529 | end if; | |
1530 | ||
0577b0b1 | 1531 | -- If an assignment target is present, then we need to generate the |
1532 | -- actual subtype if the target is a parameter or aliased object with | |
1533 | -- an unconstrained nominal subtype. | |
1534 | ||
1535 | -- Ada 2005 (AI-363): For Ada 2005, we limit the building of the actual | |
1536 | -- subtype to the parameter and dereference cases, since other aliased | |
1537 | -- objects are unconstrained (unless the nominal subtype is explicitly | |
7be5088a | 1538 | -- constrained). |
ee6ba406 | 1539 | |
1540 | if Present (Lhs) | |
1541 | and then (Present (Param_Entity (Lhs)) | |
de54c5ab | 1542 | or else (Ada_Version < Ada_2005 |
0577b0b1 | 1543 | and then not Is_Constrained (T_Typ) |
ee6ba406 | 1544 | and then Is_Aliased_View (Lhs) |
0577b0b1 | 1545 | and then not Is_Aliased_Unconstrained_Component) |
de54c5ab | 1546 | or else (Ada_Version >= Ada_2005 |
0577b0b1 | 1547 | and then not Is_Constrained (T_Typ) |
7be5088a | 1548 | and then Denotes_Explicit_Dereference (Lhs) |
0577b0b1 | 1549 | and then Nkind (Original_Node (Lhs)) /= |
1550 | N_Function_Call)) | |
ee6ba406 | 1551 | then |
1552 | T_Typ := Get_Actual_Subtype (Lhs); | |
1553 | end if; | |
1554 | ||
feff2f05 | 1555 | -- Nothing to do if the type is unconstrained (this is the case where |
1556 | -- the actual subtype in the RM sense of N is unconstrained and no check | |
1557 | -- is required). | |
ee6ba406 | 1558 | |
1559 | if not Is_Constrained (T_Typ) then | |
1560 | return; | |
05fcfafb | 1561 | |
1562 | -- Ada 2005: nothing to do if the type is one for which there is a | |
1563 | -- partial view that is constrained. | |
1564 | ||
de54c5ab | 1565 | elsif Ada_Version >= Ada_2005 |
0d78d2d4 | 1566 | and then Object_Type_Has_Constrained_Partial_View |
d41a3f41 | 1567 | (Typ => Base_Type (T_Typ), |
1568 | Scop => Current_Scope) | |
05fcfafb | 1569 | then |
1570 | return; | |
ee6ba406 | 1571 | end if; |
1572 | ||
00f91aef | 1573 | -- Nothing to do if the type is an Unchecked_Union |
1574 | ||
1575 | if Is_Unchecked_Union (Base_Type (T_Typ)) then | |
1576 | return; | |
1577 | end if; | |
1578 | ||
8d11916f | 1579 | -- Suppress checks if the subtypes are the same. The check must be |
feff2f05 | 1580 | -- preserved in an assignment to a formal, because the constraint is |
1581 | -- given by the actual. | |
ee6ba406 | 1582 | |
1583 | if Nkind (Original_Node (N)) /= N_Allocator | |
1584 | and then (No (Lhs) | |
8143bf7c | 1585 | or else not Is_Entity_Name (Lhs) |
1586 | or else No (Param_Entity (Lhs))) | |
ee6ba406 | 1587 | then |
1588 | if (Etype (N) = Typ | |
1589 | or else (Do_Access and then Designated_Type (Typ) = S_Typ)) | |
1590 | and then not Is_Aliased_View (Lhs) | |
1591 | then | |
1592 | return; | |
1593 | end if; | |
1594 | ||
feff2f05 | 1595 | -- We can also eliminate checks on allocators with a subtype mark that |
1596 | -- coincides with the context type. The context type may be a subtype | |
1597 | -- without a constraint (common case, a generic actual). | |
ee6ba406 | 1598 | |
1599 | elsif Nkind (Original_Node (N)) = N_Allocator | |
1600 | and then Is_Entity_Name (Expression (Original_Node (N))) | |
1601 | then | |
1602 | declare | |
9dfe12ae | 1603 | Alloc_Typ : constant Entity_Id := |
b6341c67 | 1604 | Entity (Expression (Original_Node (N))); |
ee6ba406 | 1605 | |
1606 | begin | |
1607 | if Alloc_Typ = T_Typ | |
1608 | or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration | |
1609 | and then Is_Entity_Name ( | |
1610 | Subtype_Indication (Parent (T_Typ))) | |
1611 | and then Alloc_Typ = Base_Type (T_Typ)) | |
1612 | ||
1613 | then | |
1614 | return; | |
1615 | end if; | |
1616 | end; | |
1617 | end if; | |
1618 | ||
feff2f05 | 1619 | -- See if we have a case where the types are both constrained, and all |
1620 | -- the constraints are constants. In this case, we can do the check | |
1621 | -- successfully at compile time. | |
ee6ba406 | 1622 | |
8d11916f | 1623 | -- We skip this check for the case where the node is rewritten as |
d7ec9a29 | 1624 | -- an allocator, because it already carries the context subtype, |
1625 | -- and extracting the discriminants from the aggregate is messy. | |
ee6ba406 | 1626 | |
1627 | if Is_Constrained (S_Typ) | |
1628 | and then Nkind (Original_Node (N)) /= N_Allocator | |
1629 | then | |
1630 | declare | |
1631 | DconT : Elmt_Id; | |
1632 | Discr : Entity_Id; | |
1633 | DconS : Elmt_Id; | |
1634 | ItemS : Node_Id; | |
1635 | ItemT : Node_Id; | |
1636 | ||
1637 | begin | |
1638 | -- S_Typ may not have discriminants in the case where it is a | |
feff2f05 | 1639 | -- private type completed by a default discriminated type. In that |
8d11916f | 1640 | -- case, we need to get the constraints from the underlying type. |
feff2f05 | 1641 | -- If the underlying type is unconstrained (i.e. has no default |
1642 | -- discriminants) no check is needed. | |
ee6ba406 | 1643 | |
1644 | if Has_Discriminants (S_Typ) then | |
1645 | Discr := First_Discriminant (S_Typ); | |
1646 | DconS := First_Elmt (Discriminant_Constraint (S_Typ)); | |
1647 | ||
1648 | else | |
1649 | Discr := First_Discriminant (Underlying_Type (S_Typ)); | |
1650 | DconS := | |
1651 | First_Elmt | |
1652 | (Discriminant_Constraint (Underlying_Type (S_Typ))); | |
1653 | ||
1654 | if No (DconS) then | |
1655 | return; | |
1656 | end if; | |
fccb5da7 | 1657 | |
1658 | -- A further optimization: if T_Typ is derived from S_Typ | |
1659 | -- without imposing a constraint, no check is needed. | |
1660 | ||
1661 | if Nkind (Original_Node (Parent (T_Typ))) = | |
1662 | N_Full_Type_Declaration | |
1663 | then | |
1664 | declare | |
5c61a0ff | 1665 | Type_Def : constant Node_Id := |
b6341c67 | 1666 | Type_Definition (Original_Node (Parent (T_Typ))); |
fccb5da7 | 1667 | begin |
1668 | if Nkind (Type_Def) = N_Derived_Type_Definition | |
1669 | and then Is_Entity_Name (Subtype_Indication (Type_Def)) | |
1670 | and then Entity (Subtype_Indication (Type_Def)) = S_Typ | |
1671 | then | |
1672 | return; | |
1673 | end if; | |
1674 | end; | |
1675 | end if; | |
ee6ba406 | 1676 | end if; |
1677 | ||
86594966 | 1678 | -- Constraint may appear in full view of type |
1679 | ||
1680 | if Ekind (T_Typ) = E_Private_Subtype | |
1681 | and then Present (Full_View (T_Typ)) | |
1682 | then | |
d7ec9a29 | 1683 | DconT := |
86594966 | 1684 | First_Elmt (Discriminant_Constraint (Full_View (T_Typ))); |
86594966 | 1685 | else |
d7ec9a29 | 1686 | DconT := |
1687 | First_Elmt (Discriminant_Constraint (T_Typ)); | |
86594966 | 1688 | end if; |
ee6ba406 | 1689 | |
1690 | while Present (Discr) loop | |
1691 | ItemS := Node (DconS); | |
1692 | ItemT := Node (DconT); | |
1693 | ||
00c403ee | 1694 | -- For a discriminated component type constrained by the |
1695 | -- current instance of an enclosing type, there is no | |
1696 | -- applicable discriminant check. | |
1697 | ||
1698 | if Nkind (ItemT) = N_Attribute_Reference | |
1699 | and then Is_Access_Type (Etype (ItemT)) | |
1700 | and then Is_Entity_Name (Prefix (ItemT)) | |
1701 | and then Is_Type (Entity (Prefix (ItemT))) | |
1702 | then | |
1703 | return; | |
1704 | end if; | |
1705 | ||
cc60bd16 | 1706 | -- If the expressions for the discriminants are identical |
1707 | -- and it is side-effect free (for now just an entity), | |
1708 | -- this may be a shared constraint, e.g. from a subtype | |
1709 | -- without a constraint introduced as a generic actual. | |
1710 | -- Examine other discriminants if any. | |
1711 | ||
1712 | if ItemS = ItemT | |
1713 | and then Is_Entity_Name (ItemS) | |
1714 | then | |
1715 | null; | |
1716 | ||
1717 | elsif not Is_OK_Static_Expression (ItemS) | |
1718 | or else not Is_OK_Static_Expression (ItemT) | |
1719 | then | |
1720 | exit; | |
ee6ba406 | 1721 | |
cc60bd16 | 1722 | elsif Expr_Value (ItemS) /= Expr_Value (ItemT) then |
ee6ba406 | 1723 | if Do_Access then -- needs run-time check. |
1724 | exit; | |
1725 | else | |
1726 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 1727 | (N, "incorrect value for discriminant&??", |
f15731c4 | 1728 | CE_Discriminant_Check_Failed, Ent => Discr); |
ee6ba406 | 1729 | return; |
1730 | end if; | |
1731 | end if; | |
1732 | ||
1733 | Next_Elmt (DconS); | |
1734 | Next_Elmt (DconT); | |
1735 | Next_Discriminant (Discr); | |
1736 | end loop; | |
1737 | ||
1738 | if No (Discr) then | |
1739 | return; | |
1740 | end if; | |
1741 | end; | |
1742 | end if; | |
1743 | ||
1744 | -- Here we need a discriminant check. First build the expression | |
1745 | -- for the comparisons of the discriminants: | |
1746 | ||
1747 | -- (n.disc1 /= typ.disc1) or else | |
1748 | -- (n.disc2 /= typ.disc2) or else | |
1749 | -- ... | |
1750 | -- (n.discn /= typ.discn) | |
1751 | ||
1752 | Cond := Build_Discriminant_Checks (N, T_Typ); | |
1753 | ||
3cce7f32 | 1754 | -- If Lhs is set and is a parameter, then the condition is guarded by: |
1755 | -- lhs'constrained and then (condition built above) | |
ee6ba406 | 1756 | |
1757 | if Present (Param_Entity (Lhs)) then | |
1758 | Cond := | |
1759 | Make_And_Then (Loc, | |
1760 | Left_Opnd => | |
1761 | Make_Attribute_Reference (Loc, | |
1762 | Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc), | |
1763 | Attribute_Name => Name_Constrained), | |
1764 | Right_Opnd => Cond); | |
1765 | end if; | |
1766 | ||
1767 | if Do_Access then | |
1768 | Cond := Guard_Access (Cond, Loc, N); | |
1769 | end if; | |
1770 | ||
1771 | Insert_Action (N, | |
f15731c4 | 1772 | Make_Raise_Constraint_Error (Loc, |
1773 | Condition => Cond, | |
1774 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 1775 | end Apply_Discriminant_Check; |
1776 | ||
2fe22c69 | 1777 | ------------------------- |
1778 | -- Apply_Divide_Checks -- | |
1779 | ------------------------- | |
ee6ba406 | 1780 | |
2fe22c69 | 1781 | procedure Apply_Divide_Checks (N : Node_Id) is |
ee6ba406 | 1782 | Loc : constant Source_Ptr := Sloc (N); |
1783 | Typ : constant Entity_Id := Etype (N); | |
1784 | Left : constant Node_Id := Left_Opnd (N); | |
1785 | Right : constant Node_Id := Right_Opnd (N); | |
1786 | ||
db415383 | 1787 | Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
2fe22c69 | 1788 | -- Current overflow checking mode |
1789 | ||
ee6ba406 | 1790 | LLB : Uint; |
1791 | Llo : Uint; | |
1792 | Lhi : Uint; | |
1793 | LOK : Boolean; | |
1794 | Rlo : Uint; | |
1795 | Rhi : Uint; | |
2fe22c69 | 1796 | ROK : Boolean; |
96da3284 | 1797 | |
1798 | pragma Warnings (Off, Lhi); | |
1799 | -- Don't actually use this value | |
ee6ba406 | 1800 | |
1801 | begin | |
0df9d43f | 1802 | -- If we are operating in MINIMIZED or ELIMINATED mode, and we are |
1803 | -- operating on signed integer types, then the only thing this routine | |
1804 | -- does is to call Apply_Arithmetic_Overflow_Minimized_Eliminated. That | |
1805 | -- procedure will (possibly later on during recursive downward calls), | |
1806 | -- ensure that any needed overflow/division checks are properly applied. | |
2fe22c69 | 1807 | |
1808 | if Mode in Minimized_Or_Eliminated | |
2fe22c69 | 1809 | and then Is_Signed_Integer_Type (Typ) |
1810 | then | |
1811 | Apply_Arithmetic_Overflow_Minimized_Eliminated (N); | |
1812 | return; | |
1813 | end if; | |
1814 | ||
1815 | -- Proceed here in SUPPRESSED or CHECKED modes | |
1816 | ||
a33565dd | 1817 | if Expander_Active |
13dbf220 | 1818 | and then not Backend_Divide_Checks_On_Target |
1819 | and then Check_Needed (Right, Division_Check) | |
ee6ba406 | 1820 | then |
9c486805 | 1821 | Determine_Range (Right, ROK, Rlo, Rhi, Assume_Valid => True); |
ee6ba406 | 1822 | |
2fe22c69 | 1823 | -- Deal with division check |
ee6ba406 | 1824 | |
2fe22c69 | 1825 | if Do_Division_Check (N) |
1826 | and then not Division_Checks_Suppressed (Typ) | |
1827 | then | |
1828 | Apply_Division_Check (N, Rlo, Rhi, ROK); | |
ee6ba406 | 1829 | end if; |
1830 | ||
2fe22c69 | 1831 | -- Deal with overflow check |
1832 | ||
0df9d43f | 1833 | if Do_Overflow_Check (N) |
1834 | and then not Overflow_Checks_Suppressed (Etype (N)) | |
1835 | then | |
f3ccbbb3 | 1836 | Set_Do_Overflow_Check (N, False); |
1837 | ||
2fe22c69 | 1838 | -- Test for extremely annoying case of xxx'First divided by -1 |
1839 | -- for division of signed integer types (only overflow case). | |
ee6ba406 | 1840 | |
ee6ba406 | 1841 | if Nkind (N) = N_Op_Divide |
1842 | and then Is_Signed_Integer_Type (Typ) | |
1843 | then | |
9c486805 | 1844 | Determine_Range (Left, LOK, Llo, Lhi, Assume_Valid => True); |
ee6ba406 | 1845 | LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ))); |
1846 | ||
1847 | if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) | |
2fe22c69 | 1848 | and then |
1849 | ((not LOK) or else (Llo = LLB)) | |
ee6ba406 | 1850 | then |
1851 | Insert_Action (N, | |
1852 | Make_Raise_Constraint_Error (Loc, | |
1853 | Condition => | |
1854 | Make_And_Then (Loc, | |
2fe22c69 | 1855 | Left_Opnd => |
1856 | Make_Op_Eq (Loc, | |
1857 | Left_Opnd => | |
1858 | Duplicate_Subexpr_Move_Checks (Left), | |
1859 | Right_Opnd => Make_Integer_Literal (Loc, LLB)), | |
ee6ba406 | 1860 | |
2fe22c69 | 1861 | Right_Opnd => |
1862 | Make_Op_Eq (Loc, | |
1863 | Left_Opnd => Duplicate_Subexpr (Right), | |
1864 | Right_Opnd => Make_Integer_Literal (Loc, -1))), | |
ee6ba406 | 1865 | |
f15731c4 | 1866 | Reason => CE_Overflow_Check_Failed)); |
ee6ba406 | 1867 | end if; |
1868 | end if; | |
1869 | end if; | |
1870 | end if; | |
2fe22c69 | 1871 | end Apply_Divide_Checks; |
1872 | ||
1873 | -------------------------- | |
1874 | -- Apply_Division_Check -- | |
1875 | -------------------------- | |
1876 | ||
1877 | procedure Apply_Division_Check | |
1878 | (N : Node_Id; | |
1879 | Rlo : Uint; | |
1880 | Rhi : Uint; | |
1881 | ROK : Boolean) | |
1882 | is | |
1883 | pragma Assert (Do_Division_Check (N)); | |
1884 | ||
1885 | Loc : constant Source_Ptr := Sloc (N); | |
1886 | Right : constant Node_Id := Right_Opnd (N); | |
1887 | ||
1888 | begin | |
a33565dd | 1889 | if Expander_Active |
2fe22c69 | 1890 | and then not Backend_Divide_Checks_On_Target |
1891 | and then Check_Needed (Right, Division_Check) | |
1892 | then | |
1893 | -- See if division by zero possible, and if so generate test. This | |
1894 | -- part of the test is not controlled by the -gnato switch, since | |
1895 | -- it is a Division_Check and not an Overflow_Check. | |
1896 | ||
1897 | if Do_Division_Check (N) then | |
f3ccbbb3 | 1898 | Set_Do_Division_Check (N, False); |
1899 | ||
2fe22c69 | 1900 | if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then |
1901 | Insert_Action (N, | |
1902 | Make_Raise_Constraint_Error (Loc, | |
1903 | Condition => | |
1904 | Make_Op_Eq (Loc, | |
1905 | Left_Opnd => Duplicate_Subexpr_Move_Checks (Right), | |
1906 | Right_Opnd => Make_Integer_Literal (Loc, 0)), | |
1907 | Reason => CE_Divide_By_Zero)); | |
1908 | end if; | |
1909 | end if; | |
1910 | end if; | |
1911 | end Apply_Division_Check; | |
ee6ba406 | 1912 | |
5329ca64 | 1913 | ---------------------------------- |
1914 | -- Apply_Float_Conversion_Check -- | |
1915 | ---------------------------------- | |
1916 | ||
feff2f05 | 1917 | -- Let F and I be the source and target types of the conversion. The RM |
1918 | -- specifies that a floating-point value X is rounded to the nearest | |
1919 | -- integer, with halfway cases being rounded away from zero. The rounded | |
1920 | -- value of X is checked against I'Range. | |
1921 | ||
1922 | -- The catch in the above paragraph is that there is no good way to know | |
1923 | -- whether the round-to-integer operation resulted in overflow. A remedy is | |
1924 | -- to perform a range check in the floating-point domain instead, however: | |
5329ca64 | 1925 | |
5329ca64 | 1926 | -- (1) The bounds may not be known at compile time |
2af58f67 | 1927 | -- (2) The check must take into account rounding or truncation. |
5329ca64 | 1928 | -- (3) The range of type I may not be exactly representable in F. |
2af58f67 | 1929 | -- (4) For the rounding case, The end-points I'First - 0.5 and |
1930 | -- I'Last + 0.5 may or may not be in range, depending on the | |
1931 | -- sign of I'First and I'Last. | |
5329ca64 | 1932 | -- (5) X may be a NaN, which will fail any comparison |
1933 | ||
2af58f67 | 1934 | -- The following steps correctly convert X with rounding: |
feff2f05 | 1935 | |
5329ca64 | 1936 | -- (1) If either I'First or I'Last is not known at compile time, use |
1937 | -- I'Base instead of I in the next three steps and perform a | |
1938 | -- regular range check against I'Range after conversion. | |
1939 | -- (2) If I'First - 0.5 is representable in F then let Lo be that | |
1940 | -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be | |
2af58f67 | 1941 | -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First). |
1942 | -- In other words, take one of the closest floating-point numbers | |
1943 | -- (which is an integer value) to I'First, and see if it is in | |
1944 | -- range or not. | |
5329ca64 | 1945 | -- (3) If I'Last + 0.5 is representable in F then let Hi be that value |
1946 | -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be | |
2af58f67 | 1947 | -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last). |
5329ca64 | 1948 | -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo) |
1949 | -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi) | |
1950 | ||
2af58f67 | 1951 | -- For the truncating case, replace steps (2) and (3) as follows: |
1952 | -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK | |
1953 | -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let | |
1954 | -- Lo_OK be True. | |
1955 | -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK | |
1956 | -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let | |
141d591a | 1957 | -- Hi_OK be True. |
2af58f67 | 1958 | |
5329ca64 | 1959 | procedure Apply_Float_Conversion_Check |
1960 | (Ck_Node : Node_Id; | |
1961 | Target_Typ : Entity_Id) | |
1962 | is | |
feff2f05 | 1963 | LB : constant Node_Id := Type_Low_Bound (Target_Typ); |
1964 | HB : constant Node_Id := Type_High_Bound (Target_Typ); | |
5329ca64 | 1965 | Loc : constant Source_Ptr := Sloc (Ck_Node); |
1966 | Expr_Type : constant Entity_Id := Base_Type (Etype (Ck_Node)); | |
feff2f05 | 1967 | Target_Base : constant Entity_Id := |
b6341c67 | 1968 | Implementation_Base_Type (Target_Typ); |
feff2f05 | 1969 | |
2af58f67 | 1970 | Par : constant Node_Id := Parent (Ck_Node); |
1971 | pragma Assert (Nkind (Par) = N_Type_Conversion); | |
1972 | -- Parent of check node, must be a type conversion | |
1973 | ||
1974 | Truncate : constant Boolean := Float_Truncate (Par); | |
1975 | Max_Bound : constant Uint := | |
b6341c67 | 1976 | UI_Expon |
1977 | (Machine_Radix_Value (Expr_Type), | |
1978 | Machine_Mantissa_Value (Expr_Type) - 1) - 1; | |
2af58f67 | 1979 | |
5329ca64 | 1980 | -- Largest bound, so bound plus or minus half is a machine number of F |
1981 | ||
feff2f05 | 1982 | Ifirst, Ilast : Uint; |
1983 | -- Bounds of integer type | |
1984 | ||
1985 | Lo, Hi : Ureal; | |
1986 | -- Bounds to check in floating-point domain | |
5329ca64 | 1987 | |
feff2f05 | 1988 | Lo_OK, Hi_OK : Boolean; |
1989 | -- True iff Lo resp. Hi belongs to I'Range | |
5329ca64 | 1990 | |
feff2f05 | 1991 | Lo_Chk, Hi_Chk : Node_Id; |
1992 | -- Expressions that are False iff check fails | |
1993 | ||
1994 | Reason : RT_Exception_Code; | |
5329ca64 | 1995 | |
1996 | begin | |
41f06abf | 1997 | -- We do not need checks if we are not generating code (i.e. the full |
1998 | -- expander is not active). In SPARK mode, we specifically don't want | |
1999 | -- the frontend to expand these checks, which are dealt with directly | |
2000 | -- in the formal verification backend. | |
2001 | ||
a33565dd | 2002 | if not Expander_Active then |
41f06abf | 2003 | return; |
2004 | end if; | |
2005 | ||
5329ca64 | 2006 | if not Compile_Time_Known_Value (LB) |
2007 | or not Compile_Time_Known_Value (HB) | |
2008 | then | |
2009 | declare | |
feff2f05 | 2010 | -- First check that the value falls in the range of the base type, |
2011 | -- to prevent overflow during conversion and then perform a | |
2012 | -- regular range check against the (dynamic) bounds. | |
5329ca64 | 2013 | |
5329ca64 | 2014 | pragma Assert (Target_Base /= Target_Typ); |
5329ca64 | 2015 | |
46eb6933 | 2016 | Temp : constant Entity_Id := Make_Temporary (Loc, 'T', Par); |
5329ca64 | 2017 | |
2018 | begin | |
2019 | Apply_Float_Conversion_Check (Ck_Node, Target_Base); | |
2020 | Set_Etype (Temp, Target_Base); | |
2021 | ||
2022 | Insert_Action (Parent (Par), | |
2023 | Make_Object_Declaration (Loc, | |
2024 | Defining_Identifier => Temp, | |
2025 | Object_Definition => New_Occurrence_Of (Target_Typ, Loc), | |
2026 | Expression => New_Copy_Tree (Par)), | |
2027 | Suppress => All_Checks); | |
2028 | ||
2029 | Insert_Action (Par, | |
2030 | Make_Raise_Constraint_Error (Loc, | |
2031 | Condition => | |
2032 | Make_Not_In (Loc, | |
2033 | Left_Opnd => New_Occurrence_Of (Temp, Loc), | |
2034 | Right_Opnd => New_Occurrence_Of (Target_Typ, Loc)), | |
2035 | Reason => CE_Range_Check_Failed)); | |
2036 | Rewrite (Par, New_Occurrence_Of (Temp, Loc)); | |
2037 | ||
2038 | return; | |
2039 | end; | |
2040 | end if; | |
2041 | ||
7d86aa98 | 2042 | -- Get the (static) bounds of the target type |
5329ca64 | 2043 | |
2044 | Ifirst := Expr_Value (LB); | |
2045 | Ilast := Expr_Value (HB); | |
2046 | ||
7d86aa98 | 2047 | -- A simple optimization: if the expression is a universal literal, |
2048 | -- we can do the comparison with the bounds and the conversion to | |
2049 | -- an integer type statically. The range checks are unchanged. | |
2050 | ||
2051 | if Nkind (Ck_Node) = N_Real_Literal | |
2052 | and then Etype (Ck_Node) = Universal_Real | |
2053 | and then Is_Integer_Type (Target_Typ) | |
2054 | and then Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
2055 | then | |
2056 | declare | |
2057 | Int_Val : constant Uint := UR_To_Uint (Realval (Ck_Node)); | |
2058 | ||
2059 | begin | |
2060 | if Int_Val <= Ilast and then Int_Val >= Ifirst then | |
2061 | ||
4309515d | 2062 | -- Conversion is safe |
7d86aa98 | 2063 | |
2064 | Rewrite (Parent (Ck_Node), | |
2065 | Make_Integer_Literal (Loc, UI_To_Int (Int_Val))); | |
2066 | Analyze_And_Resolve (Parent (Ck_Node), Target_Typ); | |
2067 | return; | |
2068 | end if; | |
2069 | end; | |
2070 | end if; | |
2071 | ||
5329ca64 | 2072 | -- Check against lower bound |
2073 | ||
2af58f67 | 2074 | if Truncate and then Ifirst > 0 then |
2075 | Lo := Pred (Expr_Type, UR_From_Uint (Ifirst)); | |
2076 | Lo_OK := False; | |
2077 | ||
2078 | elsif Truncate then | |
2079 | Lo := Succ (Expr_Type, UR_From_Uint (Ifirst - 1)); | |
2080 | Lo_OK := True; | |
2081 | ||
2082 | elsif abs (Ifirst) < Max_Bound then | |
5329ca64 | 2083 | Lo := UR_From_Uint (Ifirst) - Ureal_Half; |
2084 | Lo_OK := (Ifirst > 0); | |
2af58f67 | 2085 | |
5329ca64 | 2086 | else |
2087 | Lo := Machine (Expr_Type, UR_From_Uint (Ifirst), Round_Even, Ck_Node); | |
2088 | Lo_OK := (Lo >= UR_From_Uint (Ifirst)); | |
2089 | end if; | |
2090 | ||
2091 | if Lo_OK then | |
2092 | ||
2093 | -- Lo_Chk := (X >= Lo) | |
2094 | ||
2095 | Lo_Chk := Make_Op_Ge (Loc, | |
2096 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2097 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
2098 | ||
2099 | else | |
2100 | -- Lo_Chk := (X > Lo) | |
2101 | ||
2102 | Lo_Chk := Make_Op_Gt (Loc, | |
2103 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2104 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
2105 | end if; | |
2106 | ||
2107 | -- Check against higher bound | |
2108 | ||
2af58f67 | 2109 | if Truncate and then Ilast < 0 then |
2110 | Hi := Succ (Expr_Type, UR_From_Uint (Ilast)); | |
b2c42753 | 2111 | Hi_OK := False; |
2af58f67 | 2112 | |
2113 | elsif Truncate then | |
2114 | Hi := Pred (Expr_Type, UR_From_Uint (Ilast + 1)); | |
2115 | Hi_OK := True; | |
2116 | ||
2117 | elsif abs (Ilast) < Max_Bound then | |
5329ca64 | 2118 | Hi := UR_From_Uint (Ilast) + Ureal_Half; |
2119 | Hi_OK := (Ilast < 0); | |
2120 | else | |
2121 | Hi := Machine (Expr_Type, UR_From_Uint (Ilast), Round_Even, Ck_Node); | |
2122 | Hi_OK := (Hi <= UR_From_Uint (Ilast)); | |
2123 | end if; | |
2124 | ||
2125 | if Hi_OK then | |
2126 | ||
2127 | -- Hi_Chk := (X <= Hi) | |
2128 | ||
2129 | Hi_Chk := Make_Op_Le (Loc, | |
2130 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2131 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
2132 | ||
2133 | else | |
2134 | -- Hi_Chk := (X < Hi) | |
2135 | ||
2136 | Hi_Chk := Make_Op_Lt (Loc, | |
2137 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2138 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
2139 | end if; | |
2140 | ||
feff2f05 | 2141 | -- If the bounds of the target type are the same as those of the base |
2142 | -- type, the check is an overflow check as a range check is not | |
2143 | -- performed in these cases. | |
5329ca64 | 2144 | |
2145 | if Expr_Value (Type_Low_Bound (Target_Base)) = Ifirst | |
2146 | and then Expr_Value (Type_High_Bound (Target_Base)) = Ilast | |
2147 | then | |
2148 | Reason := CE_Overflow_Check_Failed; | |
2149 | else | |
2150 | Reason := CE_Range_Check_Failed; | |
2151 | end if; | |
2152 | ||
2153 | -- Raise CE if either conditions does not hold | |
2154 | ||
2155 | Insert_Action (Ck_Node, | |
2156 | Make_Raise_Constraint_Error (Loc, | |
05fcfafb | 2157 | Condition => Make_Op_Not (Loc, Make_And_Then (Loc, Lo_Chk, Hi_Chk)), |
5329ca64 | 2158 | Reason => Reason)); |
2159 | end Apply_Float_Conversion_Check; | |
2160 | ||
ee6ba406 | 2161 | ------------------------ |
2162 | -- Apply_Length_Check -- | |
2163 | ------------------------ | |
2164 | ||
2165 | procedure Apply_Length_Check | |
2166 | (Ck_Node : Node_Id; | |
2167 | Target_Typ : Entity_Id; | |
2168 | Source_Typ : Entity_Id := Empty) | |
2169 | is | |
2170 | begin | |
2171 | Apply_Selected_Length_Checks | |
2172 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
2173 | end Apply_Length_Check; | |
2174 | ||
3b045963 | 2175 | ------------------------------------- |
2176 | -- Apply_Parameter_Aliasing_Checks -- | |
2177 | ------------------------------------- | |
b73adb97 | 2178 | |
3b045963 | 2179 | procedure Apply_Parameter_Aliasing_Checks |
2180 | (Call : Node_Id; | |
2181 | Subp : Entity_Id) | |
2182 | is | |
bb569db0 | 2183 | Loc : constant Source_Ptr := Sloc (Call); |
2184 | ||
3b045963 | 2185 | function May_Cause_Aliasing |
2186 | (Formal_1 : Entity_Id; | |
2187 | Formal_2 : Entity_Id) return Boolean; | |
2188 | -- Determine whether two formal parameters can alias each other | |
2189 | -- depending on their modes. | |
2190 | ||
2191 | function Original_Actual (N : Node_Id) return Node_Id; | |
2192 | -- The expander may replace an actual with a temporary for the sake of | |
2193 | -- side effect removal. The temporary may hide a potential aliasing as | |
2194 | -- it does not share the address of the actual. This routine attempts | |
2195 | -- to retrieve the original actual. | |
2196 | ||
bb569db0 | 2197 | procedure Overlap_Check |
2198 | (Actual_1 : Node_Id; | |
2199 | Actual_2 : Node_Id; | |
2200 | Formal_1 : Entity_Id; | |
2201 | Formal_2 : Entity_Id; | |
2202 | Check : in out Node_Id); | |
2203 | -- Create a check to determine whether Actual_1 overlaps with Actual_2. | |
2204 | -- If detailed exception messages are enabled, the check is augmented to | |
2205 | -- provide information about the names of the corresponding formals. See | |
2206 | -- the body for details. Actual_1 and Actual_2 denote the two actuals to | |
2207 | -- be tested. Formal_1 and Formal_2 denote the corresponding formals. | |
2208 | -- Check contains all and-ed simple tests generated so far or remains | |
2209 | -- unchanged in the case of detailed exception messaged. | |
2210 | ||
3b045963 | 2211 | ------------------------ |
2212 | -- May_Cause_Aliasing -- | |
2213 | ------------------------ | |
b73adb97 | 2214 | |
3b045963 | 2215 | function May_Cause_Aliasing |
4a9e7f0c | 2216 | (Formal_1 : Entity_Id; |
3b045963 | 2217 | Formal_2 : Entity_Id) return Boolean |
2218 | is | |
2219 | begin | |
2220 | -- The following combination cannot lead to aliasing | |
2221 | ||
2222 | -- Formal 1 Formal 2 | |
2223 | -- IN IN | |
2224 | ||
2225 | if Ekind (Formal_1) = E_In_Parameter | |
a45d946f | 2226 | and then |
2227 | Ekind (Formal_2) = E_In_Parameter | |
3b045963 | 2228 | then |
2229 | return False; | |
2230 | ||
2231 | -- The following combinations may lead to aliasing | |
2232 | ||
2233 | -- Formal 1 Formal 2 | |
2234 | -- IN OUT | |
2235 | -- IN IN OUT | |
2236 | -- OUT IN | |
2237 | -- OUT IN OUT | |
2238 | -- OUT OUT | |
2239 | ||
2240 | else | |
2241 | return True; | |
2242 | end if; | |
2243 | end May_Cause_Aliasing; | |
2244 | ||
2245 | --------------------- | |
2246 | -- Original_Actual -- | |
2247 | --------------------- | |
2248 | ||
2249 | function Original_Actual (N : Node_Id) return Node_Id is | |
2250 | begin | |
2251 | if Nkind (N) = N_Type_Conversion then | |
2252 | return Expression (N); | |
2253 | ||
2254 | -- The expander created a temporary to capture the result of a type | |
2255 | -- conversion where the expression is the real actual. | |
2256 | ||
2257 | elsif Nkind (N) = N_Identifier | |
2258 | and then Present (Original_Node (N)) | |
2259 | and then Nkind (Original_Node (N)) = N_Type_Conversion | |
2260 | then | |
2261 | return Expression (Original_Node (N)); | |
2262 | end if; | |
2263 | ||
2264 | return N; | |
2265 | end Original_Actual; | |
2266 | ||
bb569db0 | 2267 | ------------------- |
2268 | -- Overlap_Check -- | |
2269 | ------------------- | |
2270 | ||
2271 | procedure Overlap_Check | |
2272 | (Actual_1 : Node_Id; | |
2273 | Actual_2 : Node_Id; | |
2274 | Formal_1 : Entity_Id; | |
2275 | Formal_2 : Entity_Id; | |
2276 | Check : in out Node_Id) | |
2277 | is | |
29448168 | 2278 | Cond : Node_Id; |
2279 | ID_Casing : constant Casing_Type := | |
2280 | Identifier_Casing (Source_Index (Current_Sem_Unit)); | |
bb569db0 | 2281 | |
2282 | begin | |
2283 | -- Generate: | |
2284 | -- Actual_1'Overlaps_Storage (Actual_2) | |
2285 | ||
2286 | Cond := | |
2287 | Make_Attribute_Reference (Loc, | |
2288 | Prefix => New_Copy_Tree (Original_Actual (Actual_1)), | |
2289 | Attribute_Name => Name_Overlaps_Storage, | |
2290 | Expressions => | |
2291 | New_List (New_Copy_Tree (Original_Actual (Actual_2)))); | |
2292 | ||
2293 | -- Generate the following check when detailed exception messages are | |
2294 | -- enabled: | |
2295 | ||
2296 | -- if Actual_1'Overlaps_Storage (Actual_2) then | |
2297 | -- raise Program_Error with <detailed message>; | |
2298 | -- end if; | |
2299 | ||
2300 | if Exception_Extra_Info then | |
2301 | Start_String; | |
2302 | ||
2303 | -- Do not generate location information for internal calls | |
2304 | ||
2305 | if Comes_From_Source (Call) then | |
2306 | Store_String_Chars (Build_Location_String (Loc)); | |
2307 | Store_String_Char (' '); | |
2308 | end if; | |
2309 | ||
2310 | Store_String_Chars ("aliased parameters, actuals for """); | |
29448168 | 2311 | |
2312 | Get_Name_String (Chars (Formal_1)); | |
2313 | Set_Casing (ID_Casing); | |
2314 | Store_String_Chars (Name_Buffer (1 .. Name_Len)); | |
2315 | ||
bb569db0 | 2316 | Store_String_Chars (""" and """); |
29448168 | 2317 | |
2318 | Get_Name_String (Chars (Formal_2)); | |
2319 | Set_Casing (ID_Casing); | |
2320 | Store_String_Chars (Name_Buffer (1 .. Name_Len)); | |
2321 | ||
bb569db0 | 2322 | Store_String_Chars (""" overlap"); |
2323 | ||
2324 | Insert_Action (Call, | |
2325 | Make_If_Statement (Loc, | |
2326 | Condition => Cond, | |
2327 | Then_Statements => New_List ( | |
2328 | Make_Raise_Statement (Loc, | |
2329 | Name => | |
83c6c069 | 2330 | New_Occurrence_Of (Standard_Program_Error, Loc), |
bb569db0 | 2331 | Expression => Make_String_Literal (Loc, End_String))))); |
2332 | ||
2333 | -- Create a sequence of overlapping checks by and-ing them all | |
2334 | -- together. | |
2335 | ||
2336 | else | |
2337 | if No (Check) then | |
2338 | Check := Cond; | |
2339 | else | |
2340 | Check := | |
2341 | Make_And_Then (Loc, | |
2342 | Left_Opnd => Check, | |
2343 | Right_Opnd => Cond); | |
2344 | end if; | |
2345 | end if; | |
2346 | end Overlap_Check; | |
2347 | ||
3b045963 | 2348 | -- Local variables |
2349 | ||
3b045963 | 2350 | Actual_1 : Node_Id; |
2351 | Actual_2 : Node_Id; | |
2352 | Check : Node_Id; | |
3b045963 | 2353 | Formal_1 : Entity_Id; |
2354 | Formal_2 : Entity_Id; | |
2355 | ||
2356 | -- Start of processing for Apply_Parameter_Aliasing_Checks | |
2357 | ||
2358 | begin | |
bb569db0 | 2359 | Check := Empty; |
3b045963 | 2360 | |
2361 | Actual_1 := First_Actual (Call); | |
2362 | Formal_1 := First_Formal (Subp); | |
2363 | while Present (Actual_1) and then Present (Formal_1) loop | |
2364 | ||
2365 | -- Ensure that the actual is an object that is not passed by value. | |
2366 | -- Elementary types are always passed by value, therefore actuals of | |
2367 | -- such types cannot lead to aliasing. | |
2368 | ||
2369 | if Is_Object_Reference (Original_Actual (Actual_1)) | |
2370 | and then not Is_Elementary_Type (Etype (Original_Actual (Actual_1))) | |
2371 | then | |
2372 | Actual_2 := Next_Actual (Actual_1); | |
2373 | Formal_2 := Next_Formal (Formal_1); | |
2374 | while Present (Actual_2) and then Present (Formal_2) loop | |
2375 | ||
2376 | -- The other actual we are testing against must also denote | |
2377 | -- a non pass-by-value object. Generate the check only when | |
2378 | -- the mode of the two formals may lead to aliasing. | |
2379 | ||
2380 | if Is_Object_Reference (Original_Actual (Actual_2)) | |
2381 | and then not | |
2382 | Is_Elementary_Type (Etype (Original_Actual (Actual_2))) | |
2383 | and then May_Cause_Aliasing (Formal_1, Formal_2) | |
2384 | then | |
bb569db0 | 2385 | Overlap_Check |
2386 | (Actual_1 => Actual_1, | |
2387 | Actual_2 => Actual_2, | |
2388 | Formal_1 => Formal_1, | |
2389 | Formal_2 => Formal_2, | |
2390 | Check => Check); | |
3b045963 | 2391 | end if; |
2392 | ||
2393 | Next_Actual (Actual_2); | |
2394 | Next_Formal (Formal_2); | |
2395 | end loop; | |
2396 | end if; | |
2397 | ||
2398 | Next_Actual (Actual_1); | |
2399 | Next_Formal (Formal_1); | |
2400 | end loop; | |
2401 | ||
bb569db0 | 2402 | -- Place a simple check right before the call |
3b045963 | 2403 | |
bb569db0 | 2404 | if Present (Check) and then not Exception_Extra_Info then |
3b045963 | 2405 | Insert_Action (Call, |
2406 | Make_Raise_Program_Error (Loc, | |
bb569db0 | 2407 | Condition => Check, |
2408 | Reason => PE_Aliased_Parameters)); | |
3b045963 | 2409 | end if; |
2410 | end Apply_Parameter_Aliasing_Checks; | |
2411 | ||
2412 | ------------------------------------- | |
2413 | -- Apply_Parameter_Validity_Checks -- | |
2414 | ------------------------------------- | |
2415 | ||
2416 | procedure Apply_Parameter_Validity_Checks (Subp : Entity_Id) is | |
2417 | Subp_Decl : Node_Id; | |
b73adb97 | 2418 | |
4a9e7f0c | 2419 | procedure Add_Validity_Check |
2420 | (Context : Entity_Id; | |
2421 | PPC_Nam : Name_Id; | |
2422 | For_Result : Boolean := False); | |
2423 | -- Add a single 'Valid[_Scalar] check which verifies the initialization | |
2424 | -- of Context. PPC_Nam denotes the pre or post condition pragma name. | |
2425 | -- Set flag For_Result when to verify the result of a function. | |
b73adb97 | 2426 | |
4a9e7f0c | 2427 | procedure Build_PPC_Pragma (PPC_Nam : Name_Id; Check : Node_Id); |
2428 | -- Create a pre or post condition pragma with name PPC_Nam which | |
2429 | -- tests expression Check. | |
b73adb97 | 2430 | |
b73adb97 | 2431 | ------------------------ |
2432 | -- Add_Validity_Check -- | |
2433 | ------------------------ | |
2434 | ||
2435 | procedure Add_Validity_Check | |
2436 | (Context : Entity_Id; | |
4a9e7f0c | 2437 | PPC_Nam : Name_Id; |
b73adb97 | 2438 | For_Result : Boolean := False) |
2439 | is | |
4a9e7f0c | 2440 | Loc : constant Source_Ptr := Sloc (Subp); |
2441 | Typ : constant Entity_Id := Etype (Context); | |
b73adb97 | 2442 | Check : Node_Id; |
2443 | Nam : Name_Id; | |
2444 | ||
2445 | begin | |
9916a361 | 2446 | -- For scalars, generate 'Valid test |
b73adb97 | 2447 | |
2448 | if Is_Scalar_Type (Typ) then | |
2449 | Nam := Name_Valid; | |
9916a361 | 2450 | |
2451 | -- For any non-scalar with scalar parts, generate 'Valid_Scalars test | |
2452 | ||
2453 | elsif Scalar_Part_Present (Typ) then | |
b73adb97 | 2454 | Nam := Name_Valid_Scalars; |
9916a361 | 2455 | |
2456 | -- No test needed for other cases (no scalars to test) | |
2457 | ||
b73adb97 | 2458 | else |
2459 | return; | |
2460 | end if; | |
2461 | ||
2462 | -- Step 1: Create the expression to verify the validity of the | |
2463 | -- context. | |
2464 | ||
83c6c069 | 2465 | Check := New_Occurrence_Of (Context, Loc); |
b73adb97 | 2466 | |
2467 | -- When processing a function result, use 'Result. Generate | |
2468 | -- Context'Result | |
2469 | ||
2470 | if For_Result then | |
2471 | Check := | |
2472 | Make_Attribute_Reference (Loc, | |
2473 | Prefix => Check, | |
2474 | Attribute_Name => Name_Result); | |
2475 | end if; | |
2476 | ||
2477 | -- Generate: | |
2478 | -- Context['Result]'Valid[_Scalars] | |
2479 | ||
2480 | Check := | |
2481 | Make_Attribute_Reference (Loc, | |
2482 | Prefix => Check, | |
2483 | Attribute_Name => Nam); | |
2484 | ||
4a9e7f0c | 2485 | -- Step 2: Create a pre or post condition pragma |
2486 | ||
2487 | Build_PPC_Pragma (PPC_Nam, Check); | |
2488 | end Add_Validity_Check; | |
2489 | ||
2490 | ---------------------- | |
2491 | -- Build_PPC_Pragma -- | |
2492 | ---------------------- | |
b73adb97 | 2493 | |
4a9e7f0c | 2494 | procedure Build_PPC_Pragma (PPC_Nam : Name_Id; Check : Node_Id) is |
7c443ae8 | 2495 | Loc : constant Source_Ptr := Sloc (Subp); |
2496 | Decls : List_Id; | |
2497 | Prag : Node_Id; | |
4a9e7f0c | 2498 | |
2499 | begin | |
2500 | Prag := | |
2501 | Make_Pragma (Loc, | |
2502 | Pragma_Identifier => Make_Identifier (Loc, PPC_Nam), | |
2503 | Pragma_Argument_Associations => New_List ( | |
2504 | Make_Pragma_Argument_Association (Loc, | |
2505 | Chars => Name_Check, | |
2506 | Expression => Check))); | |
2507 | ||
2508 | -- Add a message unless exception messages are suppressed | |
2509 | ||
2510 | if not Exception_Locations_Suppressed then | |
2511 | Append_To (Pragma_Argument_Associations (Prag), | |
2512 | Make_Pragma_Argument_Association (Loc, | |
2513 | Chars => Name_Message, | |
2514 | Expression => | |
2515 | Make_String_Literal (Loc, | |
2516 | Strval => "failed " & Get_Name_String (PPC_Nam) & | |
2517 | " from " & Build_Location_String (Loc)))); | |
2518 | end if; | |
2519 | ||
2520 | -- Insert the pragma in the tree | |
2521 | ||
2522 | if Nkind (Parent (Subp_Decl)) = N_Compilation_Unit then | |
2523 | Add_Global_Declaration (Prag); | |
7c443ae8 | 2524 | Analyze (Prag); |
2525 | ||
2526 | -- PPC pragmas associated with subprogram bodies must be inserted in | |
2527 | -- the declarative part of the body. | |
2528 | ||
2529 | elsif Nkind (Subp_Decl) = N_Subprogram_Body then | |
2530 | Decls := Declarations (Subp_Decl); | |
2531 | ||
2532 | if No (Decls) then | |
2533 | Decls := New_List; | |
2534 | Set_Declarations (Subp_Decl, Decls); | |
2535 | end if; | |
2536 | ||
1bd93de5 | 2537 | Prepend_To (Decls, Prag); |
7c443ae8 | 2538 | |
2539 | -- Ensure the proper visibility of the subprogram body and its | |
2540 | -- parameters. | |
2541 | ||
2542 | Push_Scope (Subp); | |
2543 | Analyze (Prag); | |
2544 | Pop_Scope; | |
2545 | ||
2546 | -- For subprogram declarations insert the PPC pragma right after the | |
2547 | -- declarative node. | |
2548 | ||
b73adb97 | 2549 | else |
7c443ae8 | 2550 | Insert_After_And_Analyze (Subp_Decl, Prag); |
b73adb97 | 2551 | end if; |
4a9e7f0c | 2552 | end Build_PPC_Pragma; |
2553 | ||
2554 | -- Local variables | |
2555 | ||
2556 | Formal : Entity_Id; | |
4a9e7f0c | 2557 | Subp_Spec : Node_Id; |
2558 | ||
3b045963 | 2559 | -- Start of processing for Apply_Parameter_Validity_Checks |
b73adb97 | 2560 | |
2561 | begin | |
4a9e7f0c | 2562 | -- Extract the subprogram specification and declaration nodes |
b73adb97 | 2563 | |
4a9e7f0c | 2564 | Subp_Spec := Parent (Subp); |
a45d946f | 2565 | |
4a9e7f0c | 2566 | if Nkind (Subp_Spec) = N_Defining_Program_Unit_Name then |
2567 | Subp_Spec := Parent (Subp_Spec); | |
2568 | end if; | |
a45d946f | 2569 | |
4a9e7f0c | 2570 | Subp_Decl := Parent (Subp_Spec); |
9e58d7ed | 2571 | |
b73adb97 | 2572 | if not Comes_From_Source (Subp) |
4a9e7f0c | 2573 | |
2574 | -- Do not process formal subprograms because the corresponding actual | |
2575 | -- will receive the proper checks when the instance is analyzed. | |
2576 | ||
2577 | or else Is_Formal_Subprogram (Subp) | |
2578 | ||
a45d946f | 2579 | -- Do not process imported subprograms since pre and post conditions |
2580 | -- are never verified on routines coming from a different language. | |
4a9e7f0c | 2581 | |
b73adb97 | 2582 | or else Is_Imported (Subp) |
2583 | or else Is_Intrinsic_Subprogram (Subp) | |
4a9e7f0c | 2584 | |
a45d946f | 2585 | -- The PPC pragmas generated by this routine do not correspond to |
2586 | -- source aspects, therefore they cannot be applied to abstract | |
2587 | -- subprograms. | |
4a9e7f0c | 2588 | |
7c443ae8 | 2589 | or else Nkind (Subp_Decl) = N_Abstract_Subprogram_Declaration |
4a9e7f0c | 2590 | |
a45d946f | 2591 | -- Do not consider subprogram renaminds because the renamed entity |
2592 | -- already has the proper PPC pragmas. | |
1bd93de5 | 2593 | |
2594 | or else Nkind (Subp_Decl) = N_Subprogram_Renaming_Declaration | |
2595 | ||
a45d946f | 2596 | -- Do not process null procedures because there is no benefit of |
2597 | -- adding the checks to a no action routine. | |
4a9e7f0c | 2598 | |
2599 | or else (Nkind (Subp_Spec) = N_Procedure_Specification | |
a45d946f | 2600 | and then Null_Present (Subp_Spec)) |
b73adb97 | 2601 | then |
2602 | return; | |
2603 | end if; | |
2604 | ||
4a9e7f0c | 2605 | -- Inspect all the formals applying aliasing and scalar initialization |
2606 | -- checks where applicable. | |
b73adb97 | 2607 | |
2608 | Formal := First_Formal (Subp); | |
2609 | while Present (Formal) loop | |
4a9e7f0c | 2610 | |
2611 | -- Generate the following scalar initialization checks for each | |
2612 | -- formal parameter: | |
2613 | ||
2614 | -- mode IN - Pre => Formal'Valid[_Scalars] | |
2615 | -- mode IN OUT - Pre, Post => Formal'Valid[_Scalars] | |
2616 | -- mode OUT - Post => Formal'Valid[_Scalars] | |
2617 | ||
2618 | if Check_Validity_Of_Parameters then | |
2619 | if Ekind_In (Formal, E_In_Parameter, E_In_Out_Parameter) then | |
2620 | Add_Validity_Check (Formal, Name_Precondition, False); | |
2621 | end if; | |
2622 | ||
2623 | if Ekind_In (Formal, E_In_Out_Parameter, E_Out_Parameter) then | |
2624 | Add_Validity_Check (Formal, Name_Postcondition, False); | |
2625 | end if; | |
b73adb97 | 2626 | end if; |
2627 | ||
b73adb97 | 2628 | Next_Formal (Formal); |
2629 | end loop; | |
2630 | ||
a45d946f | 2631 | -- Generate following scalar initialization check for function result: |
4a9e7f0c | 2632 | |
2633 | -- Post => Subp'Result'Valid[_Scalars] | |
b73adb97 | 2634 | |
a45d946f | 2635 | if Check_Validity_Of_Parameters and then Ekind (Subp) = E_Function then |
4a9e7f0c | 2636 | Add_Validity_Check (Subp, Name_Postcondition, True); |
b73adb97 | 2637 | end if; |
3b045963 | 2638 | end Apply_Parameter_Validity_Checks; |
b73adb97 | 2639 | |
7aafae1c | 2640 | --------------------------- |
2641 | -- Apply_Predicate_Check -- | |
2642 | --------------------------- | |
2643 | ||
2644 | procedure Apply_Predicate_Check (N : Node_Id; Typ : Entity_Id) is | |
301d5ec3 | 2645 | S : Entity_Id; |
9e58d7ed | 2646 | |
7aafae1c | 2647 | begin |
701d57a4 | 2648 | if Present (Predicate_Function (Typ)) then |
301d5ec3 | 2649 | |
301d5ec3 | 2650 | S := Current_Scope; |
9e58d7ed | 2651 | while Present (S) and then not Is_Subprogram (S) loop |
301d5ec3 | 2652 | S := Scope (S); |
2653 | end loop; | |
2654 | ||
ea822fd4 | 2655 | -- A predicate check does not apply within internally generated |
2656 | -- subprograms, such as TSS functions. | |
2657 | ||
2658 | if Within_Internal_Subprogram then | |
301d5ec3 | 2659 | return; |
22631b41 | 2660 | |
96a2d100 | 2661 | -- If the check appears within the predicate function itself, it |
2662 | -- means that the user specified a check whose formal is the | |
2663 | -- predicated subtype itself, rather than some covering type. This | |
2664 | -- is likely to be a common error, and thus deserves a warning. | |
22631b41 | 2665 | |
0e9014a7 | 2666 | elsif Present (S) and then S = Predicate_Function (Typ) then |
96a2d100 | 2667 | Error_Msg_N |
2668 | ("predicate check includes a function call that " | |
cb97ae5c | 2669 | & "requires a predicate check??", Parent (N)); |
96a2d100 | 2670 | Error_Msg_N |
cb97ae5c | 2671 | ("\this will result in infinite recursion??", Parent (N)); |
96a2d100 | 2672 | Insert_Action (N, |
61016a7a | 2673 | Make_Raise_Storage_Error (Sloc (N), |
2674 | Reason => SE_Infinite_Recursion)); | |
22631b41 | 2675 | |
64cc9e5d | 2676 | -- Here for normal case of predicate active |
e6281d47 | 2677 | |
61016a7a | 2678 | else |
b04165c4 | 2679 | -- If the type has a static predicate and the expression is known |
2680 | -- at compile time, see if the expression satisfies the predicate. | |
3a75f20b | 2681 | |
2682 | Check_Expression_Against_Static_Predicate (N, Typ); | |
e6281d47 | 2683 | |
301d5ec3 | 2684 | Insert_Action (N, |
2685 | Make_Predicate_Check (Typ, Duplicate_Subexpr (N))); | |
2686 | end if; | |
7aafae1c | 2687 | end if; |
2688 | end Apply_Predicate_Check; | |
2689 | ||
ee6ba406 | 2690 | ----------------------- |
2691 | -- Apply_Range_Check -- | |
2692 | ----------------------- | |
2693 | ||
2694 | procedure Apply_Range_Check | |
2695 | (Ck_Node : Node_Id; | |
2696 | Target_Typ : Entity_Id; | |
2697 | Source_Typ : Entity_Id := Empty) | |
2698 | is | |
2699 | begin | |
2700 | Apply_Selected_Range_Checks | |
2701 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
2702 | end Apply_Range_Check; | |
2703 | ||
2704 | ------------------------------ | |
2705 | -- Apply_Scalar_Range_Check -- | |
2706 | ------------------------------ | |
2707 | ||
feff2f05 | 2708 | -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag |
2709 | -- off if it is already set on. | |
ee6ba406 | 2710 | |
2711 | procedure Apply_Scalar_Range_Check | |
2712 | (Expr : Node_Id; | |
2713 | Target_Typ : Entity_Id; | |
2714 | Source_Typ : Entity_Id := Empty; | |
2715 | Fixed_Int : Boolean := False) | |
2716 | is | |
2717 | Parnt : constant Node_Id := Parent (Expr); | |
2718 | S_Typ : Entity_Id; | |
2719 | Arr : Node_Id := Empty; -- initialize to prevent warning | |
2720 | Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning | |
2721 | OK : Boolean; | |
2722 | ||
2723 | Is_Subscr_Ref : Boolean; | |
2724 | -- Set true if Expr is a subscript | |
2725 | ||
2726 | Is_Unconstrained_Subscr_Ref : Boolean; | |
2727 | -- Set true if Expr is a subscript of an unconstrained array. In this | |
2728 | -- case we do not attempt to do an analysis of the value against the | |
2729 | -- range of the subscript, since we don't know the actual subtype. | |
2730 | ||
2731 | Int_Real : Boolean; | |
feff2f05 | 2732 | -- Set to True if Expr should be regarded as a real value even though |
2733 | -- the type of Expr might be discrete. | |
ee6ba406 | 2734 | |
2735 | procedure Bad_Value; | |
2736 | -- Procedure called if value is determined to be out of range | |
2737 | ||
9dfe12ae | 2738 | --------------- |
2739 | -- Bad_Value -- | |
2740 | --------------- | |
2741 | ||
ee6ba406 | 2742 | procedure Bad_Value is |
2743 | begin | |
2744 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 2745 | (Expr, "value not in range of}??", CE_Range_Check_Failed, |
ee6ba406 | 2746 | Ent => Target_Typ, |
2747 | Typ => Target_Typ); | |
2748 | end Bad_Value; | |
2749 | ||
9dfe12ae | 2750 | -- Start of processing for Apply_Scalar_Range_Check |
2751 | ||
ee6ba406 | 2752 | begin |
2af58f67 | 2753 | -- Return if check obviously not needed |
ee6ba406 | 2754 | |
2af58f67 | 2755 | if |
2756 | -- Not needed inside generic | |
ee6ba406 | 2757 | |
2af58f67 | 2758 | Inside_A_Generic |
2759 | ||
2760 | -- Not needed if previous error | |
2761 | ||
2762 | or else Target_Typ = Any_Type | |
2763 | or else Nkind (Expr) = N_Error | |
2764 | ||
2765 | -- Not needed for non-scalar type | |
2766 | ||
2767 | or else not Is_Scalar_Type (Target_Typ) | |
2768 | ||
2769 | -- Not needed if we know node raises CE already | |
2770 | ||
2771 | or else Raises_Constraint_Error (Expr) | |
ee6ba406 | 2772 | then |
2773 | return; | |
2774 | end if; | |
2775 | ||
2776 | -- Now, see if checks are suppressed | |
2777 | ||
2778 | Is_Subscr_Ref := | |
2779 | Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component; | |
2780 | ||
2781 | if Is_Subscr_Ref then | |
2782 | Arr := Prefix (Parnt); | |
2783 | Arr_Typ := Get_Actual_Subtype_If_Available (Arr); | |
cce84b09 | 2784 | |
a3a76ccc | 2785 | if Is_Access_Type (Arr_Typ) then |
245e87df | 2786 | Arr_Typ := Designated_Type (Arr_Typ); |
a3a76ccc | 2787 | end if; |
ee6ba406 | 2788 | end if; |
2789 | ||
2790 | if not Do_Range_Check (Expr) then | |
2791 | ||
2792 | -- Subscript reference. Check for Index_Checks suppressed | |
2793 | ||
2794 | if Is_Subscr_Ref then | |
2795 | ||
2796 | -- Check array type and its base type | |
2797 | ||
2798 | if Index_Checks_Suppressed (Arr_Typ) | |
9dfe12ae | 2799 | or else Index_Checks_Suppressed (Base_Type (Arr_Typ)) |
ee6ba406 | 2800 | then |
2801 | return; | |
2802 | ||
2803 | -- Check array itself if it is an entity name | |
2804 | ||
2805 | elsif Is_Entity_Name (Arr) | |
9dfe12ae | 2806 | and then Index_Checks_Suppressed (Entity (Arr)) |
ee6ba406 | 2807 | then |
2808 | return; | |
2809 | ||
2810 | -- Check expression itself if it is an entity name | |
2811 | ||
2812 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 2813 | and then Index_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 2814 | then |
2815 | return; | |
2816 | end if; | |
2817 | ||
2818 | -- All other cases, check for Range_Checks suppressed | |
2819 | ||
2820 | else | |
2821 | -- Check target type and its base type | |
2822 | ||
2823 | if Range_Checks_Suppressed (Target_Typ) | |
9dfe12ae | 2824 | or else Range_Checks_Suppressed (Base_Type (Target_Typ)) |
ee6ba406 | 2825 | then |
2826 | return; | |
2827 | ||
2828 | -- Check expression itself if it is an entity name | |
2829 | ||
2830 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 2831 | and then Range_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 2832 | then |
2833 | return; | |
2834 | ||
feff2f05 | 2835 | -- If Expr is part of an assignment statement, then check left |
2836 | -- side of assignment if it is an entity name. | |
ee6ba406 | 2837 | |
2838 | elsif Nkind (Parnt) = N_Assignment_Statement | |
2839 | and then Is_Entity_Name (Name (Parnt)) | |
9dfe12ae | 2840 | and then Range_Checks_Suppressed (Entity (Name (Parnt))) |
ee6ba406 | 2841 | then |
2842 | return; | |
2843 | end if; | |
2844 | end if; | |
2845 | end if; | |
2846 | ||
9dfe12ae | 2847 | -- Do not set range checks if they are killed |
2848 | ||
2849 | if Nkind (Expr) = N_Unchecked_Type_Conversion | |
2850 | and then Kill_Range_Check (Expr) | |
2851 | then | |
2852 | return; | |
2853 | end if; | |
2854 | ||
2855 | -- Do not set range checks for any values from System.Scalar_Values | |
39a0c1d3 | 2856 | -- since the whole idea of such values is to avoid checking them. |
9dfe12ae | 2857 | |
2858 | if Is_Entity_Name (Expr) | |
2859 | and then Is_RTU (Scope (Entity (Expr)), System_Scalar_Values) | |
2860 | then | |
2861 | return; | |
2862 | end if; | |
2863 | ||
ee6ba406 | 2864 | -- Now see if we need a check |
2865 | ||
2866 | if No (Source_Typ) then | |
2867 | S_Typ := Etype (Expr); | |
2868 | else | |
2869 | S_Typ := Source_Typ; | |
2870 | end if; | |
2871 | ||
2872 | if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then | |
2873 | return; | |
2874 | end if; | |
2875 | ||
2876 | Is_Unconstrained_Subscr_Ref := | |
2877 | Is_Subscr_Ref and then not Is_Constrained (Arr_Typ); | |
2878 | ||
b40670e1 | 2879 | -- Special checks for floating-point type |
ee6ba406 | 2880 | |
b40670e1 | 2881 | if Is_Floating_Point_Type (S_Typ) then |
2882 | ||
2883 | -- Always do a range check if the source type includes infinities and | |
2884 | -- the target type does not include infinities. We do not do this if | |
2885 | -- range checks are killed. | |
2886 | ||
2887 | if Has_Infinities (S_Typ) | |
2888 | and then not Has_Infinities (Target_Typ) | |
2889 | then | |
2890 | Enable_Range_Check (Expr); | |
b40670e1 | 2891 | end if; |
ee6ba406 | 2892 | end if; |
2893 | ||
feff2f05 | 2894 | -- Return if we know expression is definitely in the range of the target |
2895 | -- type as determined by Determine_Range. Right now we only do this for | |
2896 | -- discrete types, and not fixed-point or floating-point types. | |
ee6ba406 | 2897 | |
f2a06be9 | 2898 | -- The additional less-precise tests below catch these cases |
ee6ba406 | 2899 | |
feff2f05 | 2900 | -- Note: skip this if we are given a source_typ, since the point of |
2901 | -- supplying a Source_Typ is to stop us looking at the expression. | |
2902 | -- We could sharpen this test to be out parameters only ??? | |
ee6ba406 | 2903 | |
2904 | if Is_Discrete_Type (Target_Typ) | |
2905 | and then Is_Discrete_Type (Etype (Expr)) | |
2906 | and then not Is_Unconstrained_Subscr_Ref | |
2907 | and then No (Source_Typ) | |
2908 | then | |
2909 | declare | |
2910 | Tlo : constant Node_Id := Type_Low_Bound (Target_Typ); | |
2911 | Thi : constant Node_Id := Type_High_Bound (Target_Typ); | |
2912 | Lo : Uint; | |
2913 | Hi : Uint; | |
2914 | ||
2915 | begin | |
2916 | if Compile_Time_Known_Value (Tlo) | |
2917 | and then Compile_Time_Known_Value (Thi) | |
2918 | then | |
9dfe12ae | 2919 | declare |
2920 | Lov : constant Uint := Expr_Value (Tlo); | |
2921 | Hiv : constant Uint := Expr_Value (Thi); | |
ee6ba406 | 2922 | |
9dfe12ae | 2923 | begin |
2924 | -- If range is null, we for sure have a constraint error | |
2925 | -- (we don't even need to look at the value involved, | |
2926 | -- since all possible values will raise CE). | |
2927 | ||
2928 | if Lov > Hiv then | |
2929 | Bad_Value; | |
2930 | return; | |
2931 | end if; | |
2932 | ||
2933 | -- Otherwise determine range of value | |
2934 | ||
9c486805 | 2935 | Determine_Range (Expr, OK, Lo, Hi, Assume_Valid => True); |
9dfe12ae | 2936 | |
2937 | if OK then | |
2938 | ||
2939 | -- If definitely in range, all OK | |
ee6ba406 | 2940 | |
ee6ba406 | 2941 | if Lo >= Lov and then Hi <= Hiv then |
2942 | return; | |
2943 | ||
9dfe12ae | 2944 | -- If definitely not in range, warn |
2945 | ||
ee6ba406 | 2946 | elsif Lov > Hi or else Hiv < Lo then |
2947 | Bad_Value; | |
2948 | return; | |
9dfe12ae | 2949 | |
2950 | -- Otherwise we don't know | |
2951 | ||
2952 | else | |
2953 | null; | |
ee6ba406 | 2954 | end if; |
9dfe12ae | 2955 | end if; |
2956 | end; | |
ee6ba406 | 2957 | end if; |
2958 | end; | |
2959 | end if; | |
2960 | ||
2961 | Int_Real := | |
2962 | Is_Floating_Point_Type (S_Typ) | |
2963 | or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int); | |
2964 | ||
2965 | -- Check if we can determine at compile time whether Expr is in the | |
9dfe12ae | 2966 | -- range of the target type. Note that if S_Typ is within the bounds |
2967 | -- of Target_Typ then this must be the case. This check is meaningful | |
2968 | -- only if this is not a conversion between integer and real types. | |
ee6ba406 | 2969 | |
2970 | if not Is_Unconstrained_Subscr_Ref | |
b40670e1 | 2971 | and then Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ) |
ee6ba406 | 2972 | and then |
7a1dabb3 | 2973 | (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int) |
ee6ba406 | 2974 | or else |
9c486805 | 2975 | Is_In_Range (Expr, Target_Typ, |
2976 | Assume_Valid => True, | |
b40670e1 | 2977 | Fixed_Int => Fixed_Int, |
2978 | Int_Real => Int_Real)) | |
ee6ba406 | 2979 | then |
2980 | return; | |
2981 | ||
9c486805 | 2982 | elsif Is_Out_Of_Range (Expr, Target_Typ, |
2983 | Assume_Valid => True, | |
2984 | Fixed_Int => Fixed_Int, | |
2985 | Int_Real => Int_Real) | |
2986 | then | |
ee6ba406 | 2987 | Bad_Value; |
2988 | return; | |
2989 | ||
b40670e1 | 2990 | -- Floating-point case |
feff2f05 | 2991 | -- In the floating-point case, we only do range checks if the type is |
2992 | -- constrained. We definitely do NOT want range checks for unconstrained | |
2993 | -- types, since we want to have infinities | |
ee6ba406 | 2994 | |
9dfe12ae | 2995 | elsif Is_Floating_Point_Type (S_Typ) then |
b40670e1 | 2996 | |
2997 | -- Normally, we only do range checks if the type is constrained. We do | |
2998 | -- NOT want range checks for unconstrained types, since we want to have | |
718d0d92 | 2999 | -- infinities. |
b40670e1 | 3000 | |
718d0d92 | 3001 | if Is_Constrained (S_Typ) then |
9dfe12ae | 3002 | Enable_Range_Check (Expr); |
3003 | end if; | |
ee6ba406 | 3004 | |
9dfe12ae | 3005 | -- For all other cases we enable a range check unconditionally |
ee6ba406 | 3006 | |
3007 | else | |
3008 | Enable_Range_Check (Expr); | |
3009 | return; | |
3010 | end if; | |
ee6ba406 | 3011 | end Apply_Scalar_Range_Check; |
3012 | ||
3013 | ---------------------------------- | |
3014 | -- Apply_Selected_Length_Checks -- | |
3015 | ---------------------------------- | |
3016 | ||
3017 | procedure Apply_Selected_Length_Checks | |
3018 | (Ck_Node : Node_Id; | |
3019 | Target_Typ : Entity_Id; | |
3020 | Source_Typ : Entity_Id; | |
3021 | Do_Static : Boolean) | |
3022 | is | |
3023 | Cond : Node_Id; | |
3024 | R_Result : Check_Result; | |
3025 | R_Cno : Node_Id; | |
3026 | ||
3027 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
3028 | Checks_On : constant Boolean := | |
b6341c67 | 3029 | (not Index_Checks_Suppressed (Target_Typ)) |
4098232e | 3030 | or else (not Length_Checks_Suppressed (Target_Typ)); |
ee6ba406 | 3031 | |
3032 | begin | |
4098232e | 3033 | -- Note: this means that we lose some useful warnings if the expander |
3034 | -- is not active, and we also lose these warnings in SPARK mode ??? | |
3035 | ||
a33565dd | 3036 | if not Expander_Active then |
ee6ba406 | 3037 | return; |
3038 | end if; | |
3039 | ||
3040 | R_Result := | |
3041 | Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
3042 | ||
3043 | for J in 1 .. 2 loop | |
ee6ba406 | 3044 | R_Cno := R_Result (J); |
3045 | exit when No (R_Cno); | |
3046 | ||
3047 | -- A length check may mention an Itype which is attached to a | |
3048 | -- subsequent node. At the top level in a package this can cause | |
3049 | -- an order-of-elaboration problem, so we make sure that the itype | |
3050 | -- is referenced now. | |
3051 | ||
3052 | if Ekind (Current_Scope) = E_Package | |
3053 | and then Is_Compilation_Unit (Current_Scope) | |
3054 | then | |
3055 | Ensure_Defined (Target_Typ, Ck_Node); | |
3056 | ||
3057 | if Present (Source_Typ) then | |
3058 | Ensure_Defined (Source_Typ, Ck_Node); | |
3059 | ||
3060 | elsif Is_Itype (Etype (Ck_Node)) then | |
3061 | Ensure_Defined (Etype (Ck_Node), Ck_Node); | |
3062 | end if; | |
3063 | end if; | |
3064 | ||
feff2f05 | 3065 | -- If the item is a conditional raise of constraint error, then have |
3066 | -- a look at what check is being performed and ??? | |
ee6ba406 | 3067 | |
3068 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
3069 | and then Present (Condition (R_Cno)) | |
3070 | then | |
3071 | Cond := Condition (R_Cno); | |
3072 | ||
0577b0b1 | 3073 | -- Case where node does not now have a dynamic check |
ee6ba406 | 3074 | |
0577b0b1 | 3075 | if not Has_Dynamic_Length_Check (Ck_Node) then |
3076 | ||
3077 | -- If checks are on, just insert the check | |
3078 | ||
3079 | if Checks_On then | |
3080 | Insert_Action (Ck_Node, R_Cno); | |
3081 | ||
3082 | if not Do_Static then | |
3083 | Set_Has_Dynamic_Length_Check (Ck_Node); | |
3084 | end if; | |
3085 | ||
3086 | -- If checks are off, then analyze the length check after | |
3087 | -- temporarily attaching it to the tree in case the relevant | |
6fb3c314 | 3088 | -- condition can be evaluated at compile time. We still want a |
0577b0b1 | 3089 | -- compile time warning in this case. |
3090 | ||
3091 | else | |
3092 | Set_Parent (R_Cno, Ck_Node); | |
3093 | Analyze (R_Cno); | |
ee6ba406 | 3094 | end if; |
ee6ba406 | 3095 | end if; |
3096 | ||
3097 | -- Output a warning if the condition is known to be True | |
3098 | ||
3099 | if Is_Entity_Name (Cond) | |
3100 | and then Entity (Cond) = Standard_True | |
3101 | then | |
3102 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 3103 | (Ck_Node, "wrong length for array of}??", |
f15731c4 | 3104 | CE_Length_Check_Failed, |
ee6ba406 | 3105 | Ent => Target_Typ, |
3106 | Typ => Target_Typ); | |
3107 | ||
3108 | -- If we were only doing a static check, or if checks are not | |
3109 | -- on, then we want to delete the check, since it is not needed. | |
3110 | -- We do this by replacing the if statement by a null statement | |
3111 | ||
3112 | elsif Do_Static or else not Checks_On then | |
00c403ee | 3113 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 3114 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
3115 | end if; | |
3116 | ||
3117 | else | |
3118 | Install_Static_Check (R_Cno, Loc); | |
3119 | end if; | |
ee6ba406 | 3120 | end loop; |
ee6ba406 | 3121 | end Apply_Selected_Length_Checks; |
3122 | ||
3123 | --------------------------------- | |
3124 | -- Apply_Selected_Range_Checks -- | |
3125 | --------------------------------- | |
3126 | ||
3127 | procedure Apply_Selected_Range_Checks | |
3128 | (Ck_Node : Node_Id; | |
3129 | Target_Typ : Entity_Id; | |
3130 | Source_Typ : Entity_Id; | |
3131 | Do_Static : Boolean) | |
3132 | is | |
ee6ba406 | 3133 | Loc : constant Source_Ptr := Sloc (Ck_Node); |
3134 | Checks_On : constant Boolean := | |
f9bcba0d | 3135 | not Index_Checks_Suppressed (Target_Typ) |
5372d110 | 3136 | or else |
3137 | not Range_Checks_Suppressed (Target_Typ); | |
f9bcba0d | 3138 | |
3139 | Cond : Node_Id; | |
3140 | R_Cno : Node_Id; | |
3141 | R_Result : Check_Result; | |
ee6ba406 | 3142 | |
3143 | begin | |
5372d110 | 3144 | if not Expander_Active or not Checks_On then |
ee6ba406 | 3145 | return; |
3146 | end if; | |
3147 | ||
3148 | R_Result := | |
3149 | Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
3150 | ||
3151 | for J in 1 .. 2 loop | |
ee6ba406 | 3152 | R_Cno := R_Result (J); |
3153 | exit when No (R_Cno); | |
3154 | ||
f9bcba0d | 3155 | -- The range check requires runtime evaluation. Depending on what its |
3156 | -- triggering condition is, the check may be converted into a compile | |
3157 | -- time constraint check. | |
ee6ba406 | 3158 | |
3159 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
3160 | and then Present (Condition (R_Cno)) | |
3161 | then | |
3162 | Cond := Condition (R_Cno); | |
3163 | ||
f9bcba0d | 3164 | -- Insert the range check before the related context. Note that |
3165 | -- this action analyses the triggering condition. | |
ee6ba406 | 3166 | |
f9bcba0d | 3167 | Insert_Action (Ck_Node, R_Cno); |
3168 | ||
3169 | -- This old code doesn't make sense, why is the context flagged as | |
3170 | -- requiring dynamic range checks now in the middle of generating | |
3171 | -- them ??? | |
3172 | ||
3173 | if not Do_Static then | |
3174 | Set_Has_Dynamic_Range_Check (Ck_Node); | |
ee6ba406 | 3175 | end if; |
3176 | ||
f9bcba0d | 3177 | -- The triggering condition evaluates to True, the range check |
3178 | -- can be converted into a compile time constraint check. | |
ee6ba406 | 3179 | |
3180 | if Is_Entity_Name (Cond) | |
3181 | and then Entity (Cond) = Standard_True | |
3182 | then | |
feff2f05 | 3183 | -- Since an N_Range is technically not an expression, we have |
3184 | -- to set one of the bounds to C_E and then just flag the | |
3185 | -- N_Range. The warning message will point to the lower bound | |
3186 | -- and complain about a range, which seems OK. | |
ee6ba406 | 3187 | |
3188 | if Nkind (Ck_Node) = N_Range then | |
3189 | Apply_Compile_Time_Constraint_Error | |
5372d110 | 3190 | (Low_Bound (Ck_Node), |
3191 | "static range out of bounds of}??", | |
f15731c4 | 3192 | CE_Range_Check_Failed, |
ee6ba406 | 3193 | Ent => Target_Typ, |
3194 | Typ => Target_Typ); | |
3195 | ||
3196 | Set_Raises_Constraint_Error (Ck_Node); | |
3197 | ||
3198 | else | |
3199 | Apply_Compile_Time_Constraint_Error | |
5372d110 | 3200 | (Ck_Node, |
1581f2d7 | 3201 | "static value out of range of}??", |
f15731c4 | 3202 | CE_Range_Check_Failed, |
ee6ba406 | 3203 | Ent => Target_Typ, |
3204 | Typ => Target_Typ); | |
3205 | end if; | |
3206 | ||
3207 | -- If we were only doing a static check, or if checks are not | |
3208 | -- on, then we want to delete the check, since it is not needed. | |
3209 | -- We do this by replacing the if statement by a null statement | |
3210 | ||
f9bcba0d | 3211 | -- Why are we even generating checks if checks are turned off ??? |
3212 | ||
ee6ba406 | 3213 | elsif Do_Static or else not Checks_On then |
00c403ee | 3214 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 3215 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
3216 | end if; | |
3217 | ||
f9bcba0d | 3218 | -- The range check raises Constrant_Error explicitly |
3219 | ||
ee6ba406 | 3220 | else |
3221 | Install_Static_Check (R_Cno, Loc); | |
3222 | end if; | |
ee6ba406 | 3223 | end loop; |
ee6ba406 | 3224 | end Apply_Selected_Range_Checks; |
3225 | ||
3226 | ------------------------------- | |
3227 | -- Apply_Static_Length_Check -- | |
3228 | ------------------------------- | |
3229 | ||
3230 | procedure Apply_Static_Length_Check | |
3231 | (Expr : Node_Id; | |
3232 | Target_Typ : Entity_Id; | |
3233 | Source_Typ : Entity_Id := Empty) | |
3234 | is | |
3235 | begin | |
3236 | Apply_Selected_Length_Checks | |
3237 | (Expr, Target_Typ, Source_Typ, Do_Static => True); | |
3238 | end Apply_Static_Length_Check; | |
3239 | ||
3240 | ------------------------------------- | |
3241 | -- Apply_Subscript_Validity_Checks -- | |
3242 | ------------------------------------- | |
3243 | ||
3244 | procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is | |
3245 | Sub : Node_Id; | |
3246 | ||
3247 | begin | |
3248 | pragma Assert (Nkind (Expr) = N_Indexed_Component); | |
3249 | ||
3250 | -- Loop through subscripts | |
3251 | ||
3252 | Sub := First (Expressions (Expr)); | |
3253 | while Present (Sub) loop | |
3254 | ||
feff2f05 | 3255 | -- Check one subscript. Note that we do not worry about enumeration |
3256 | -- type with holes, since we will convert the value to a Pos value | |
3257 | -- for the subscript, and that convert will do the necessary validity | |
3258 | -- check. | |
ee6ba406 | 3259 | |
3260 | Ensure_Valid (Sub, Holes_OK => True); | |
3261 | ||
3262 | -- Move to next subscript | |
3263 | ||
3264 | Sub := Next (Sub); | |
3265 | end loop; | |
3266 | end Apply_Subscript_Validity_Checks; | |
3267 | ||
3268 | ---------------------------------- | |
3269 | -- Apply_Type_Conversion_Checks -- | |
3270 | ---------------------------------- | |
3271 | ||
3272 | procedure Apply_Type_Conversion_Checks (N : Node_Id) is | |
3273 | Target_Type : constant Entity_Id := Etype (N); | |
3274 | Target_Base : constant Entity_Id := Base_Type (Target_Type); | |
9dfe12ae | 3275 | Expr : constant Node_Id := Expression (N); |
f4532fe1 | 3276 | |
3277 | Expr_Type : constant Entity_Id := Underlying_Type (Etype (Expr)); | |
141d591a | 3278 | -- Note: if Etype (Expr) is a private type without discriminants, its |
3279 | -- full view might have discriminants with defaults, so we need the | |
3280 | -- full view here to retrieve the constraints. | |
ee6ba406 | 3281 | |
3282 | begin | |
3283 | if Inside_A_Generic then | |
3284 | return; | |
3285 | ||
f15731c4 | 3286 | -- Skip these checks if serious errors detected, there are some nasty |
ee6ba406 | 3287 | -- situations of incomplete trees that blow things up. |
3288 | ||
f15731c4 | 3289 | elsif Serious_Errors_Detected > 0 then |
ee6ba406 | 3290 | return; |
3291 | ||
ea822fd4 | 3292 | -- Never generate discriminant checks for Unchecked_Union types |
3293 | ||
3294 | elsif Present (Expr_Type) | |
3295 | and then Is_Unchecked_Union (Expr_Type) | |
3296 | then | |
3297 | return; | |
3298 | ||
feff2f05 | 3299 | -- Scalar type conversions of the form Target_Type (Expr) require a |
3300 | -- range check if we cannot be sure that Expr is in the base type of | |
3301 | -- Target_Typ and also that Expr is in the range of Target_Typ. These | |
3302 | -- are not quite the same condition from an implementation point of | |
3303 | -- view, but clearly the second includes the first. | |
ee6ba406 | 3304 | |
3305 | elsif Is_Scalar_Type (Target_Type) then | |
3306 | declare | |
3307 | Conv_OK : constant Boolean := Conversion_OK (N); | |
feff2f05 | 3308 | -- If the Conversion_OK flag on the type conversion is set and no |
ea822fd4 | 3309 | -- floating-point type is involved in the type conversion then |
3310 | -- fixed-point values must be read as integral values. | |
ee6ba406 | 3311 | |
5329ca64 | 3312 | Float_To_Int : constant Boolean := |
b6341c67 | 3313 | Is_Floating_Point_Type (Expr_Type) |
3314 | and then Is_Integer_Type (Target_Type); | |
5329ca64 | 3315 | |
ee6ba406 | 3316 | begin |
ee6ba406 | 3317 | if not Overflow_Checks_Suppressed (Target_Base) |
0df9d43f | 3318 | and then not Overflow_Checks_Suppressed (Target_Type) |
e254d721 | 3319 | and then not |
7a1dabb3 | 3320 | In_Subrange_Of (Expr_Type, Target_Base, Fixed_Int => Conv_OK) |
5329ca64 | 3321 | and then not Float_To_Int |
ee6ba406 | 3322 | then |
00c403ee | 3323 | Activate_Overflow_Check (N); |
ee6ba406 | 3324 | end if; |
3325 | ||
3326 | if not Range_Checks_Suppressed (Target_Type) | |
3327 | and then not Range_Checks_Suppressed (Expr_Type) | |
3328 | then | |
5329ca64 | 3329 | if Float_To_Int then |
3330 | Apply_Float_Conversion_Check (Expr, Target_Type); | |
3331 | else | |
3332 | Apply_Scalar_Range_Check | |
3333 | (Expr, Target_Type, Fixed_Int => Conv_OK); | |
798afddc | 3334 | |
3335 | -- If the target type has predicates, we need to indicate | |
ea822fd4 | 3336 | -- the need for a check, even if Determine_Range finds that |
3337 | -- the value is within bounds. This may be the case e.g for | |
3338 | -- a division with a constant denominator. | |
798afddc | 3339 | |
3340 | if Has_Predicates (Target_Type) then | |
3341 | Enable_Range_Check (Expr); | |
3342 | end if; | |
5329ca64 | 3343 | end if; |
ee6ba406 | 3344 | end if; |
3345 | end; | |
3346 | ||
3347 | elsif Comes_From_Source (N) | |
f40f9731 | 3348 | and then not Discriminant_Checks_Suppressed (Target_Type) |
ee6ba406 | 3349 | and then Is_Record_Type (Target_Type) |
3350 | and then Is_Derived_Type (Target_Type) | |
3351 | and then not Is_Tagged_Type (Target_Type) | |
3352 | and then not Is_Constrained (Target_Type) | |
9dfe12ae | 3353 | and then Present (Stored_Constraint (Target_Type)) |
ee6ba406 | 3354 | then |
141d591a | 3355 | -- An unconstrained derived type may have inherited discriminant. |
9dfe12ae | 3356 | -- Build an actual discriminant constraint list using the stored |
ee6ba406 | 3357 | -- constraint, to verify that the expression of the parent type |
ea822fd4 | 3358 | -- satisfies the constraints imposed by the (unconstrained) derived |
3359 | -- type. This applies to value conversions, not to view conversions | |
3360 | -- of tagged types. | |
ee6ba406 | 3361 | |
3362 | declare | |
9dfe12ae | 3363 | Loc : constant Source_Ptr := Sloc (N); |
3364 | Cond : Node_Id; | |
3365 | Constraint : Elmt_Id; | |
3366 | Discr_Value : Node_Id; | |
3367 | Discr : Entity_Id; | |
3368 | ||
3369 | New_Constraints : constant Elist_Id := New_Elmt_List; | |
3370 | Old_Constraints : constant Elist_Id := | |
b6341c67 | 3371 | Discriminant_Constraint (Expr_Type); |
ee6ba406 | 3372 | |
3373 | begin | |
9dfe12ae | 3374 | Constraint := First_Elmt (Stored_Constraint (Target_Type)); |
ee6ba406 | 3375 | while Present (Constraint) loop |
3376 | Discr_Value := Node (Constraint); | |
3377 | ||
3378 | if Is_Entity_Name (Discr_Value) | |
3379 | and then Ekind (Entity (Discr_Value)) = E_Discriminant | |
3380 | then | |
3381 | Discr := Corresponding_Discriminant (Entity (Discr_Value)); | |
3382 | ||
3383 | if Present (Discr) | |
3384 | and then Scope (Discr) = Base_Type (Expr_Type) | |
3385 | then | |
3386 | -- Parent is constrained by new discriminant. Obtain | |
feff2f05 | 3387 | -- Value of original discriminant in expression. If the |
3388 | -- new discriminant has been used to constrain more than | |
3389 | -- one of the stored discriminants, this will provide the | |
3390 | -- required consistency check. | |
ee6ba406 | 3391 | |
55868293 | 3392 | Append_Elmt |
3393 | (Make_Selected_Component (Loc, | |
3394 | Prefix => | |
9dfe12ae | 3395 | Duplicate_Subexpr_No_Checks |
3396 | (Expr, Name_Req => True), | |
ee6ba406 | 3397 | Selector_Name => |
3398 | Make_Identifier (Loc, Chars (Discr))), | |
55868293 | 3399 | New_Constraints); |
ee6ba406 | 3400 | |
3401 | else | |
3402 | -- Discriminant of more remote ancestor ??? | |
3403 | ||
3404 | return; | |
3405 | end if; | |
3406 | ||
feff2f05 | 3407 | -- Derived type definition has an explicit value for this |
3408 | -- stored discriminant. | |
ee6ba406 | 3409 | |
3410 | else | |
3411 | Append_Elmt | |
9dfe12ae | 3412 | (Duplicate_Subexpr_No_Checks (Discr_Value), |
3413 | New_Constraints); | |
ee6ba406 | 3414 | end if; |
3415 | ||
3416 | Next_Elmt (Constraint); | |
3417 | end loop; | |
3418 | ||
3419 | -- Use the unconstrained expression type to retrieve the | |
3420 | -- discriminants of the parent, and apply momentarily the | |
3421 | -- discriminant constraint synthesized above. | |
3422 | ||
3423 | Set_Discriminant_Constraint (Expr_Type, New_Constraints); | |
3424 | Cond := Build_Discriminant_Checks (Expr, Expr_Type); | |
3425 | Set_Discriminant_Constraint (Expr_Type, Old_Constraints); | |
3426 | ||
3427 | Insert_Action (N, | |
f15731c4 | 3428 | Make_Raise_Constraint_Error (Loc, |
3429 | Condition => Cond, | |
3430 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 3431 | end; |
3432 | ||
175a6969 | 3433 | -- For arrays, checks are set now, but conversions are applied during |
3434 | -- expansion, to take into accounts changes of representation. The | |
3435 | -- checks become range checks on the base type or length checks on the | |
3436 | -- subtype, depending on whether the target type is unconstrained or | |
8e802312 | 3437 | -- constrained. Note that the range check is put on the expression of a |
3438 | -- type conversion, while the length check is put on the type conversion | |
3439 | -- itself. | |
175a6969 | 3440 | |
3441 | elsif Is_Array_Type (Target_Type) then | |
3442 | if Is_Constrained (Target_Type) then | |
3443 | Set_Do_Length_Check (N); | |
3444 | else | |
3445 | Set_Do_Range_Check (Expr); | |
3446 | end if; | |
ee6ba406 | 3447 | end if; |
ee6ba406 | 3448 | end Apply_Type_Conversion_Checks; |
3449 | ||
3450 | ---------------------------------------------- | |
3451 | -- Apply_Universal_Integer_Attribute_Checks -- | |
3452 | ---------------------------------------------- | |
3453 | ||
3454 | procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is | |
3455 | Loc : constant Source_Ptr := Sloc (N); | |
3456 | Typ : constant Entity_Id := Etype (N); | |
3457 | ||
3458 | begin | |
3459 | if Inside_A_Generic then | |
3460 | return; | |
3461 | ||
3462 | -- Nothing to do if checks are suppressed | |
3463 | ||
3464 | elsif Range_Checks_Suppressed (Typ) | |
3465 | and then Overflow_Checks_Suppressed (Typ) | |
3466 | then | |
3467 | return; | |
3468 | ||
3469 | -- Nothing to do if the attribute does not come from source. The | |
3470 | -- internal attributes we generate of this type do not need checks, | |
3471 | -- and furthermore the attempt to check them causes some circular | |
3472 | -- elaboration orders when dealing with packed types. | |
3473 | ||
3474 | elsif not Comes_From_Source (N) then | |
3475 | return; | |
3476 | ||
9dfe12ae | 3477 | -- If the prefix is a selected component that depends on a discriminant |
3478 | -- the check may improperly expose a discriminant instead of using | |
3479 | -- the bounds of the object itself. Set the type of the attribute to | |
3480 | -- the base type of the context, so that a check will be imposed when | |
3481 | -- needed (e.g. if the node appears as an index). | |
3482 | ||
3483 | elsif Nkind (Prefix (N)) = N_Selected_Component | |
3484 | and then Ekind (Typ) = E_Signed_Integer_Subtype | |
3485 | and then Depends_On_Discriminant (Scalar_Range (Typ)) | |
3486 | then | |
3487 | Set_Etype (N, Base_Type (Typ)); | |
3488 | ||
feff2f05 | 3489 | -- Otherwise, replace the attribute node with a type conversion node |
3490 | -- whose expression is the attribute, retyped to universal integer, and | |
3491 | -- whose subtype mark is the target type. The call to analyze this | |
3492 | -- conversion will set range and overflow checks as required for proper | |
3493 | -- detection of an out of range value. | |
ee6ba406 | 3494 | |
3495 | else | |
3496 | Set_Etype (N, Universal_Integer); | |
3497 | Set_Analyzed (N, True); | |
3498 | ||
3499 | Rewrite (N, | |
3500 | Make_Type_Conversion (Loc, | |
3501 | Subtype_Mark => New_Occurrence_Of (Typ, Loc), | |
3502 | Expression => Relocate_Node (N))); | |
3503 | ||
3504 | Analyze_And_Resolve (N, Typ); | |
3505 | return; | |
3506 | end if; | |
ee6ba406 | 3507 | end Apply_Universal_Integer_Attribute_Checks; |
3508 | ||
07c191b0 | 3509 | ------------------------------------- |
3510 | -- Atomic_Synchronization_Disabled -- | |
3511 | ------------------------------------- | |
3512 | ||
3513 | -- Note: internally Disable/Enable_Atomic_Synchronization is implemented | |
3514 | -- using a bogus check called Atomic_Synchronization. This is to make it | |
3515 | -- more convenient to get exactly the same semantics as [Un]Suppress. | |
3516 | ||
3517 | function Atomic_Synchronization_Disabled (E : Entity_Id) return Boolean is | |
3518 | begin | |
b444f81d | 3519 | -- If debug flag d.e is set, always return False, i.e. all atomic sync |
3520 | -- looks enabled, since it is never disabled. | |
3521 | ||
3522 | if Debug_Flag_Dot_E then | |
3523 | return False; | |
3524 | ||
3525 | -- If debug flag d.d is set then always return True, i.e. all atomic | |
3526 | -- sync looks disabled, since it always tests True. | |
3527 | ||
3528 | elsif Debug_Flag_Dot_D then | |
3529 | return True; | |
3530 | ||
3531 | -- If entity present, then check result for that entity | |
3532 | ||
3533 | elsif Present (E) and then Checks_May_Be_Suppressed (E) then | |
07c191b0 | 3534 | return Is_Check_Suppressed (E, Atomic_Synchronization); |
b444f81d | 3535 | |
3536 | -- Otherwise result depends on current scope setting | |
3537 | ||
07c191b0 | 3538 | else |
fafc6b97 | 3539 | return Scope_Suppress.Suppress (Atomic_Synchronization); |
07c191b0 | 3540 | end if; |
3541 | end Atomic_Synchronization_Disabled; | |
3542 | ||
ee6ba406 | 3543 | ------------------------------- |
3544 | -- Build_Discriminant_Checks -- | |
3545 | ------------------------------- | |
3546 | ||
3547 | function Build_Discriminant_Checks | |
3548 | (N : Node_Id; | |
314a23b6 | 3549 | T_Typ : Entity_Id) return Node_Id |
ee6ba406 | 3550 | is |
3551 | Loc : constant Source_Ptr := Sloc (N); | |
3552 | Cond : Node_Id; | |
3553 | Disc : Elmt_Id; | |
3554 | Disc_Ent : Entity_Id; | |
9dfe12ae | 3555 | Dref : Node_Id; |
ee6ba406 | 3556 | Dval : Node_Id; |
3557 | ||
84d0d4a5 | 3558 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id; |
3559 | ||
3560 | ---------------------------------- | |
3561 | -- Aggregate_Discriminant_Value -- | |
3562 | ---------------------------------- | |
3563 | ||
3564 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id is | |
3565 | Assoc : Node_Id; | |
3566 | ||
3567 | begin | |
feff2f05 | 3568 | -- The aggregate has been normalized with named associations. We use |
3569 | -- the Chars field to locate the discriminant to take into account | |
3570 | -- discriminants in derived types, which carry the same name as those | |
3571 | -- in the parent. | |
84d0d4a5 | 3572 | |
3573 | Assoc := First (Component_Associations (N)); | |
3574 | while Present (Assoc) loop | |
3575 | if Chars (First (Choices (Assoc))) = Chars (Disc) then | |
3576 | return Expression (Assoc); | |
3577 | else | |
3578 | Next (Assoc); | |
3579 | end if; | |
3580 | end loop; | |
3581 | ||
3582 | -- Discriminant must have been found in the loop above | |
3583 | ||
3584 | raise Program_Error; | |
3585 | end Aggregate_Discriminant_Val; | |
3586 | ||
3587 | -- Start of processing for Build_Discriminant_Checks | |
3588 | ||
ee6ba406 | 3589 | begin |
84d0d4a5 | 3590 | -- Loop through discriminants evolving the condition |
3591 | ||
ee6ba406 | 3592 | Cond := Empty; |
3593 | Disc := First_Elmt (Discriminant_Constraint (T_Typ)); | |
3594 | ||
9dfe12ae | 3595 | -- For a fully private type, use the discriminants of the parent type |
ee6ba406 | 3596 | |
3597 | if Is_Private_Type (T_Typ) | |
3598 | and then No (Full_View (T_Typ)) | |
3599 | then | |
3600 | Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ))); | |
3601 | else | |
3602 | Disc_Ent := First_Discriminant (T_Typ); | |
3603 | end if; | |
3604 | ||
3605 | while Present (Disc) loop | |
ee6ba406 | 3606 | Dval := Node (Disc); |
3607 | ||
3608 | if Nkind (Dval) = N_Identifier | |
3609 | and then Ekind (Entity (Dval)) = E_Discriminant | |
3610 | then | |
3611 | Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc); | |
3612 | else | |
9dfe12ae | 3613 | Dval := Duplicate_Subexpr_No_Checks (Dval); |
ee6ba406 | 3614 | end if; |
3615 | ||
00f91aef | 3616 | -- If we have an Unchecked_Union node, we can infer the discriminants |
3617 | -- of the node. | |
9dfe12ae | 3618 | |
00f91aef | 3619 | if Is_Unchecked_Union (Base_Type (T_Typ)) then |
3620 | Dref := New_Copy ( | |
3621 | Get_Discriminant_Value ( | |
3622 | First_Discriminant (T_Typ), | |
3623 | T_Typ, | |
3624 | Stored_Constraint (T_Typ))); | |
3625 | ||
84d0d4a5 | 3626 | elsif Nkind (N) = N_Aggregate then |
3627 | Dref := | |
3628 | Duplicate_Subexpr_No_Checks | |
3629 | (Aggregate_Discriminant_Val (Disc_Ent)); | |
3630 | ||
00f91aef | 3631 | else |
3632 | Dref := | |
3633 | Make_Selected_Component (Loc, | |
20cf157b | 3634 | Prefix => |
00f91aef | 3635 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
20cf157b | 3636 | Selector_Name => Make_Identifier (Loc, Chars (Disc_Ent))); |
00f91aef | 3637 | |
3638 | Set_Is_In_Discriminant_Check (Dref); | |
3639 | end if; | |
9dfe12ae | 3640 | |
ee6ba406 | 3641 | Evolve_Or_Else (Cond, |
3642 | Make_Op_Ne (Loc, | |
20cf157b | 3643 | Left_Opnd => Dref, |
ee6ba406 | 3644 | Right_Opnd => Dval)); |
3645 | ||
3646 | Next_Elmt (Disc); | |
3647 | Next_Discriminant (Disc_Ent); | |
3648 | end loop; | |
3649 | ||
3650 | return Cond; | |
3651 | end Build_Discriminant_Checks; | |
3652 | ||
13dbf220 | 3653 | ------------------ |
3654 | -- Check_Needed -- | |
3655 | ------------------ | |
3656 | ||
3657 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean is | |
3658 | N : Node_Id; | |
3659 | P : Node_Id; | |
3660 | K : Node_Kind; | |
3661 | L : Node_Id; | |
3662 | R : Node_Id; | |
3663 | ||
9b2068d4 | 3664 | function Left_Expression (Op : Node_Id) return Node_Id; |
3665 | -- Return the relevant expression from the left operand of the given | |
3666 | -- short circuit form: this is LO itself, except if LO is a qualified | |
3667 | -- expression, a type conversion, or an expression with actions, in | |
3668 | -- which case this is Left_Expression (Expression (LO)). | |
3669 | ||
3670 | --------------------- | |
3671 | -- Left_Expression -- | |
3672 | --------------------- | |
3673 | ||
3674 | function Left_Expression (Op : Node_Id) return Node_Id is | |
3675 | LE : Node_Id := Left_Opnd (Op); | |
3676 | begin | |
20cf157b | 3677 | while Nkind_In (LE, N_Qualified_Expression, |
3678 | N_Type_Conversion, | |
3679 | N_Expression_With_Actions) | |
9b2068d4 | 3680 | loop |
3681 | LE := Expression (LE); | |
3682 | end loop; | |
3683 | ||
3684 | return LE; | |
3685 | end Left_Expression; | |
3686 | ||
3687 | -- Start of processing for Check_Needed | |
3688 | ||
13dbf220 | 3689 | begin |
3690 | -- Always check if not simple entity | |
3691 | ||
3692 | if Nkind (Nod) not in N_Has_Entity | |
3693 | or else not Comes_From_Source (Nod) | |
3694 | then | |
3695 | return True; | |
3696 | end if; | |
3697 | ||
3698 | -- Look up tree for short circuit | |
3699 | ||
3700 | N := Nod; | |
3701 | loop | |
3702 | P := Parent (N); | |
3703 | K := Nkind (P); | |
3704 | ||
7b17e51b | 3705 | -- Done if out of subexpression (note that we allow generated stuff |
3706 | -- such as itype declarations in this context, to keep the loop going | |
3707 | -- since we may well have generated such stuff in complex situations. | |
3708 | -- Also done if no parent (probably an error condition, but no point | |
39a0c1d3 | 3709 | -- in behaving nasty if we find it). |
7b17e51b | 3710 | |
3711 | if No (P) | |
3712 | or else (K not in N_Subexpr and then Comes_From_Source (P)) | |
3713 | then | |
13dbf220 | 3714 | return True; |
3715 | ||
7b17e51b | 3716 | -- Or/Or Else case, where test is part of the right operand, or is |
3717 | -- part of one of the actions associated with the right operand, and | |
3718 | -- the left operand is an equality test. | |
13dbf220 | 3719 | |
7b17e51b | 3720 | elsif K = N_Op_Or then |
13dbf220 | 3721 | exit when N = Right_Opnd (P) |
9b2068d4 | 3722 | and then Nkind (Left_Expression (P)) = N_Op_Eq; |
13dbf220 | 3723 | |
7b17e51b | 3724 | elsif K = N_Or_Else then |
3725 | exit when (N = Right_Opnd (P) | |
3726 | or else | |
3727 | (Is_List_Member (N) | |
3728 | and then List_Containing (N) = Actions (P))) | |
9b2068d4 | 3729 | and then Nkind (Left_Expression (P)) = N_Op_Eq; |
13dbf220 | 3730 | |
7b17e51b | 3731 | -- Similar test for the And/And then case, where the left operand |
3732 | -- is an inequality test. | |
3733 | ||
3734 | elsif K = N_Op_And then | |
13dbf220 | 3735 | exit when N = Right_Opnd (P) |
9b2068d4 | 3736 | and then Nkind (Left_Expression (P)) = N_Op_Ne; |
7b17e51b | 3737 | |
3738 | elsif K = N_And_Then then | |
3739 | exit when (N = Right_Opnd (P) | |
3740 | or else | |
3741 | (Is_List_Member (N) | |
20cf157b | 3742 | and then List_Containing (N) = Actions (P))) |
9b2068d4 | 3743 | and then Nkind (Left_Expression (P)) = N_Op_Ne; |
13dbf220 | 3744 | end if; |
3745 | ||
3746 | N := P; | |
3747 | end loop; | |
3748 | ||
3749 | -- If we fall through the loop, then we have a conditional with an | |
9b2068d4 | 3750 | -- appropriate test as its left operand, so look further. |
3751 | ||
3752 | L := Left_Expression (P); | |
3753 | ||
3754 | -- L is an "=" or "/=" operator: extract its operands | |
13dbf220 | 3755 | |
13dbf220 | 3756 | R := Right_Opnd (L); |
3757 | L := Left_Opnd (L); | |
3758 | ||
3759 | -- Left operand of test must match original variable | |
3760 | ||
20cf157b | 3761 | if Nkind (L) not in N_Has_Entity or else Entity (L) /= Entity (Nod) then |
13dbf220 | 3762 | return True; |
3763 | end if; | |
3764 | ||
2af58f67 | 3765 | -- Right operand of test must be key value (zero or null) |
13dbf220 | 3766 | |
3767 | case Check is | |
3768 | when Access_Check => | |
2af58f67 | 3769 | if not Known_Null (R) then |
13dbf220 | 3770 | return True; |
3771 | end if; | |
3772 | ||
3773 | when Division_Check => | |
3774 | if not Compile_Time_Known_Value (R) | |
3775 | or else Expr_Value (R) /= Uint_0 | |
3776 | then | |
3777 | return True; | |
3778 | end if; | |
2af58f67 | 3779 | |
3780 | when others => | |
3781 | raise Program_Error; | |
13dbf220 | 3782 | end case; |
3783 | ||
3784 | -- Here we have the optimizable case, warn if not short-circuited | |
3785 | ||
3786 | if K = N_Op_And or else K = N_Op_Or then | |
c4968aa2 | 3787 | Error_Msg_Warn := SPARK_Mode /= On; |
4098232e | 3788 | |
13dbf220 | 3789 | case Check is |
3790 | when Access_Check => | |
4098232e | 3791 | if GNATprove_Mode then |
3792 | Error_Msg_N | |
3793 | ("Constraint_Error might have been raised (access check)", | |
3794 | Parent (Nod)); | |
3795 | else | |
3796 | Error_Msg_N | |
3797 | ("Constraint_Error may be raised (access check)??", | |
3798 | Parent (Nod)); | |
3799 | end if; | |
3800 | ||
13dbf220 | 3801 | when Division_Check => |
4098232e | 3802 | if GNATprove_Mode then |
3803 | Error_Msg_N | |
3804 | ("Constraint_Error might have been raised (zero divide)", | |
3805 | Parent (Nod)); | |
3806 | else | |
3807 | Error_Msg_N | |
3808 | ("Constraint_Error may be raised (zero divide)??", | |
3809 | Parent (Nod)); | |
3810 | end if; | |
2af58f67 | 3811 | |
3812 | when others => | |
3813 | raise Program_Error; | |
13dbf220 | 3814 | end case; |
3815 | ||
3816 | if K = N_Op_And then | |
e977c0cf | 3817 | Error_Msg_N -- CODEFIX |
cb97ae5c | 3818 | ("use `AND THEN` instead of AND??", P); |
13dbf220 | 3819 | else |
e977c0cf | 3820 | Error_Msg_N -- CODEFIX |
cb97ae5c | 3821 | ("use `OR ELSE` instead of OR??", P); |
13dbf220 | 3822 | end if; |
3823 | ||
6fb3c314 | 3824 | -- If not short-circuited, we need the check |
13dbf220 | 3825 | |
3826 | return True; | |
3827 | ||
3828 | -- If short-circuited, we can omit the check | |
3829 | ||
3830 | else | |
3831 | return False; | |
3832 | end if; | |
3833 | end Check_Needed; | |
3834 | ||
ee6ba406 | 3835 | ----------------------------------- |
3836 | -- Check_Valid_Lvalue_Subscripts -- | |
3837 | ----------------------------------- | |
3838 | ||
3839 | procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is | |
3840 | begin | |
3841 | -- Skip this if range checks are suppressed | |
3842 | ||
3843 | if Range_Checks_Suppressed (Etype (Expr)) then | |
3844 | return; | |
3845 | ||
feff2f05 | 3846 | -- Only do this check for expressions that come from source. We assume |
3847 | -- that expander generated assignments explicitly include any necessary | |
3848 | -- checks. Note that this is not just an optimization, it avoids | |
39a0c1d3 | 3849 | -- infinite recursions. |
ee6ba406 | 3850 | |
3851 | elsif not Comes_From_Source (Expr) then | |
3852 | return; | |
3853 | ||
3854 | -- For a selected component, check the prefix | |
3855 | ||
3856 | elsif Nkind (Expr) = N_Selected_Component then | |
3857 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
3858 | return; | |
3859 | ||
3860 | -- Case of indexed component | |
3861 | ||
3862 | elsif Nkind (Expr) = N_Indexed_Component then | |
3863 | Apply_Subscript_Validity_Checks (Expr); | |
3864 | ||
feff2f05 | 3865 | -- Prefix may itself be or contain an indexed component, and these |
3866 | -- subscripts need checking as well. | |
ee6ba406 | 3867 | |
3868 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
3869 | end if; | |
3870 | end Check_Valid_Lvalue_Subscripts; | |
3871 | ||
fa7497e8 | 3872 | ---------------------------------- |
3873 | -- Null_Exclusion_Static_Checks -- | |
3874 | ---------------------------------- | |
3875 | ||
3876 | procedure Null_Exclusion_Static_Checks (N : Node_Id) is | |
0577b0b1 | 3877 | Error_Node : Node_Id; |
3878 | Expr : Node_Id; | |
3879 | Has_Null : constant Boolean := Has_Null_Exclusion (N); | |
3880 | K : constant Node_Kind := Nkind (N); | |
3881 | Typ : Entity_Id; | |
fa7497e8 | 3882 | |
13dbf220 | 3883 | begin |
0577b0b1 | 3884 | pragma Assert |
ea822fd4 | 3885 | (Nkind_In (K, N_Component_Declaration, |
3886 | N_Discriminant_Specification, | |
3887 | N_Function_Specification, | |
3888 | N_Object_Declaration, | |
3889 | N_Parameter_Specification)); | |
0577b0b1 | 3890 | |
3891 | if K = N_Function_Specification then | |
3892 | Typ := Etype (Defining_Entity (N)); | |
3893 | else | |
3894 | Typ := Etype (Defining_Identifier (N)); | |
3895 | end if; | |
fa7497e8 | 3896 | |
13dbf220 | 3897 | case K is |
13dbf220 | 3898 | when N_Component_Declaration => |
3899 | if Present (Access_Definition (Component_Definition (N))) then | |
0577b0b1 | 3900 | Error_Node := Component_Definition (N); |
13dbf220 | 3901 | else |
0577b0b1 | 3902 | Error_Node := Subtype_Indication (Component_Definition (N)); |
13dbf220 | 3903 | end if; |
5329ca64 | 3904 | |
0577b0b1 | 3905 | when N_Discriminant_Specification => |
3906 | Error_Node := Discriminant_Type (N); | |
3907 | ||
3908 | when N_Function_Specification => | |
3909 | Error_Node := Result_Definition (N); | |
3910 | ||
3911 | when N_Object_Declaration => | |
3912 | Error_Node := Object_Definition (N); | |
3913 | ||
3914 | when N_Parameter_Specification => | |
3915 | Error_Node := Parameter_Type (N); | |
3916 | ||
13dbf220 | 3917 | when others => |
3918 | raise Program_Error; | |
3919 | end case; | |
5329ca64 | 3920 | |
0577b0b1 | 3921 | if Has_Null then |
5329ca64 | 3922 | |
0577b0b1 | 3923 | -- Enforce legality rule 3.10 (13): A null exclusion can only be |
3924 | -- applied to an access [sub]type. | |
5329ca64 | 3925 | |
0577b0b1 | 3926 | if not Is_Access_Type (Typ) then |
503f7fd3 | 3927 | Error_Msg_N |
00c403ee | 3928 | ("`NOT NULL` allowed only for an access type", Error_Node); |
5329ca64 | 3929 | |
feff2f05 | 3930 | -- Enforce legality rule RM 3.10(14/1): A null exclusion can only |
0577b0b1 | 3931 | -- be applied to a [sub]type that does not exclude null already. |
3932 | ||
3933 | elsif Can_Never_Be_Null (Typ) | |
d16989f1 | 3934 | and then Comes_From_Source (Typ) |
0577b0b1 | 3935 | then |
503f7fd3 | 3936 | Error_Msg_NE |
00c403ee | 3937 | ("`NOT NULL` not allowed (& already excludes null)", |
3938 | Error_Node, Typ); | |
0577b0b1 | 3939 | end if; |
13dbf220 | 3940 | end if; |
5329ca64 | 3941 | |
cc60bd16 | 3942 | -- Check that null-excluding objects are always initialized, except for |
3943 | -- deferred constants, for which the expression will appear in the full | |
3944 | -- declaration. | |
13dbf220 | 3945 | |
3946 | if K = N_Object_Declaration | |
84d0d4a5 | 3947 | and then No (Expression (N)) |
cc60bd16 | 3948 | and then not Constant_Present (N) |
feff2f05 | 3949 | and then not No_Initialization (N) |
13dbf220 | 3950 | then |
feff2f05 | 3951 | -- Add an expression that assigns null. This node is needed by |
3952 | -- Apply_Compile_Time_Constraint_Error, which will replace this with | |
3953 | -- a Constraint_Error node. | |
13dbf220 | 3954 | |
3955 | Set_Expression (N, Make_Null (Sloc (N))); | |
3956 | Set_Etype (Expression (N), Etype (Defining_Identifier (N))); | |
5329ca64 | 3957 | |
13dbf220 | 3958 | Apply_Compile_Time_Constraint_Error |
3959 | (N => Expression (N), | |
cb97ae5c | 3960 | Msg => |
3961 | "(Ada 2005) null-excluding objects must be initialized??", | |
13dbf220 | 3962 | Reason => CE_Null_Not_Allowed); |
3963 | end if; | |
5329ca64 | 3964 | |
cc60bd16 | 3965 | -- Check that a null-excluding component, formal or object is not being |
3966 | -- assigned a null value. Otherwise generate a warning message and | |
2c145f84 | 3967 | -- replace Expression (N) by an N_Constraint_Error node. |
13dbf220 | 3968 | |
0577b0b1 | 3969 | if K /= N_Function_Specification then |
3970 | Expr := Expression (N); | |
5329ca64 | 3971 | |
2af58f67 | 3972 | if Present (Expr) and then Known_Null (Expr) then |
13dbf220 | 3973 | case K is |
0577b0b1 | 3974 | when N_Component_Declaration | |
3975 | N_Discriminant_Specification => | |
7189d17f | 3976 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 3977 | (N => Expr, |
4098232e | 3978 | Msg => "(Ada 2005) null not allowed " |
3979 | & "in null-excluding components??", | |
0577b0b1 | 3980 | Reason => CE_Null_Not_Allowed); |
5329ca64 | 3981 | |
0577b0b1 | 3982 | when N_Object_Declaration => |
7189d17f | 3983 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 3984 | (N => Expr, |
4098232e | 3985 | Msg => "(Ada 2005) null not allowed " |
1581f2d7 | 3986 | & "in null-excluding objects??", |
0577b0b1 | 3987 | Reason => CE_Null_Not_Allowed); |
5329ca64 | 3988 | |
0577b0b1 | 3989 | when N_Parameter_Specification => |
7189d17f | 3990 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 3991 | (N => Expr, |
4098232e | 3992 | Msg => "(Ada 2005) null not allowed " |
3993 | & "in null-excluding formals??", | |
0577b0b1 | 3994 | Reason => CE_Null_Not_Allowed); |
13dbf220 | 3995 | |
3996 | when others => | |
3997 | null; | |
5329ca64 | 3998 | end case; |
3999 | end if; | |
0577b0b1 | 4000 | end if; |
fa7497e8 | 4001 | end Null_Exclusion_Static_Checks; |
4002 | ||
9dfe12ae | 4003 | ---------------------------------- |
4004 | -- Conditional_Statements_Begin -- | |
4005 | ---------------------------------- | |
4006 | ||
4007 | procedure Conditional_Statements_Begin is | |
4008 | begin | |
4009 | Saved_Checks_TOS := Saved_Checks_TOS + 1; | |
4010 | ||
feff2f05 | 4011 | -- If stack overflows, kill all checks, that way we know to simply reset |
4012 | -- the number of saved checks to zero on return. This should never occur | |
4013 | -- in practice. | |
9dfe12ae | 4014 | |
4015 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
4016 | Kill_All_Checks; | |
4017 | ||
feff2f05 | 4018 | -- In the normal case, we just make a new stack entry saving the current |
4019 | -- number of saved checks for a later restore. | |
9dfe12ae | 4020 | |
4021 | else | |
4022 | Saved_Checks_Stack (Saved_Checks_TOS) := Num_Saved_Checks; | |
4023 | ||
4024 | if Debug_Flag_CC then | |
4025 | w ("Conditional_Statements_Begin: Num_Saved_Checks = ", | |
4026 | Num_Saved_Checks); | |
4027 | end if; | |
4028 | end if; | |
4029 | end Conditional_Statements_Begin; | |
4030 | ||
4031 | -------------------------------- | |
4032 | -- Conditional_Statements_End -- | |
4033 | -------------------------------- | |
4034 | ||
4035 | procedure Conditional_Statements_End is | |
4036 | begin | |
4037 | pragma Assert (Saved_Checks_TOS > 0); | |
4038 | ||
feff2f05 | 4039 | -- If the saved checks stack overflowed, then we killed all checks, so |
4040 | -- setting the number of saved checks back to zero is correct. This | |
4041 | -- should never occur in practice. | |
9dfe12ae | 4042 | |
4043 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
4044 | Num_Saved_Checks := 0; | |
4045 | ||
feff2f05 | 4046 | -- In the normal case, restore the number of saved checks from the top |
4047 | -- stack entry. | |
9dfe12ae | 4048 | |
4049 | else | |
4050 | Num_Saved_Checks := Saved_Checks_Stack (Saved_Checks_TOS); | |
20cf157b | 4051 | |
9dfe12ae | 4052 | if Debug_Flag_CC then |
4053 | w ("Conditional_Statements_End: Num_Saved_Checks = ", | |
4054 | Num_Saved_Checks); | |
4055 | end if; | |
4056 | end if; | |
4057 | ||
4058 | Saved_Checks_TOS := Saved_Checks_TOS - 1; | |
4059 | end Conditional_Statements_End; | |
4060 | ||
3cce7f32 | 4061 | ------------------------- |
4062 | -- Convert_From_Bignum -- | |
4063 | ------------------------- | |
4064 | ||
4065 | function Convert_From_Bignum (N : Node_Id) return Node_Id is | |
4066 | Loc : constant Source_Ptr := Sloc (N); | |
4067 | ||
4068 | begin | |
4069 | pragma Assert (Is_RTE (Etype (N), RE_Bignum)); | |
4070 | ||
4071 | -- Construct call From Bignum | |
4072 | ||
4073 | return | |
4074 | Make_Function_Call (Loc, | |
4075 | Name => | |
4076 | New_Occurrence_Of (RTE (RE_From_Bignum), Loc), | |
4077 | Parameter_Associations => New_List (Relocate_Node (N))); | |
4078 | end Convert_From_Bignum; | |
4079 | ||
4080 | ----------------------- | |
4081 | -- Convert_To_Bignum -- | |
4082 | ----------------------- | |
4083 | ||
4084 | function Convert_To_Bignum (N : Node_Id) return Node_Id is | |
4085 | Loc : constant Source_Ptr := Sloc (N); | |
4086 | ||
4087 | begin | |
0326b4d4 | 4088 | -- Nothing to do if Bignum already except call Relocate_Node |
3cce7f32 | 4089 | |
4090 | if Is_RTE (Etype (N), RE_Bignum) then | |
4091 | return Relocate_Node (N); | |
4092 | ||
21a55437 | 4093 | -- Otherwise construct call to To_Bignum, converting the operand to the |
4094 | -- required Long_Long_Integer form. | |
3cce7f32 | 4095 | |
4096 | else | |
4097 | pragma Assert (Is_Signed_Integer_Type (Etype (N))); | |
4098 | return | |
4099 | Make_Function_Call (Loc, | |
4100 | Name => | |
4101 | New_Occurrence_Of (RTE (RE_To_Bignum), Loc), | |
4102 | Parameter_Associations => New_List ( | |
4103 | Convert_To (Standard_Long_Long_Integer, Relocate_Node (N)))); | |
4104 | end if; | |
4105 | end Convert_To_Bignum; | |
4106 | ||
ee6ba406 | 4107 | --------------------- |
4108 | -- Determine_Range -- | |
4109 | --------------------- | |
4110 | ||
6af1bdbc | 4111 | Cache_Size : constant := 2 ** 10; |
ee6ba406 | 4112 | type Cache_Index is range 0 .. Cache_Size - 1; |
39a0c1d3 | 4113 | -- Determine size of below cache (power of 2 is more efficient) |
ee6ba406 | 4114 | |
7ac8c2b1 | 4115 | Determine_Range_Cache_N : array (Cache_Index) of Node_Id; |
4116 | Determine_Range_Cache_V : array (Cache_Index) of Boolean; | |
4117 | Determine_Range_Cache_Lo : array (Cache_Index) of Uint; | |
4118 | Determine_Range_Cache_Hi : array (Cache_Index) of Uint; | |
4119 | Determine_Range_Cache_Lo_R : array (Cache_Index) of Ureal; | |
4120 | Determine_Range_Cache_Hi_R : array (Cache_Index) of Ureal; | |
feff2f05 | 4121 | -- The above arrays are used to implement a small direct cache for |
7ac8c2b1 | 4122 | -- Determine_Range and Determine_Range_R calls. Because of the way these |
4123 | -- subprograms recursively traces subexpressions, and because overflow | |
4124 | -- checking calls the routine on the way up the tree, a quadratic behavior | |
4125 | -- can otherwise be encountered in large expressions. The cache entry for | |
4126 | -- node N is stored in the (N mod Cache_Size) entry, and can be validated | |
4127 | -- by checking the actual node value stored there. The Range_Cache_V array | |
4128 | -- records the setting of Assume_Valid for the cache entry. | |
ee6ba406 | 4129 | |
4130 | procedure Determine_Range | |
9c486805 | 4131 | (N : Node_Id; |
4132 | OK : out Boolean; | |
4133 | Lo : out Uint; | |
4134 | Hi : out Uint; | |
4135 | Assume_Valid : Boolean := False) | |
ee6ba406 | 4136 | is |
e254d721 | 4137 | Typ : Entity_Id := Etype (N); |
4138 | -- Type to use, may get reset to base type for possibly invalid entity | |
8880be85 | 4139 | |
4140 | Lo_Left : Uint; | |
4141 | Hi_Left : Uint; | |
4142 | -- Lo and Hi bounds of left operand | |
ee6ba406 | 4143 | |
ee6ba406 | 4144 | Lo_Right : Uint; |
ee6ba406 | 4145 | Hi_Right : Uint; |
8880be85 | 4146 | -- Lo and Hi bounds of right (or only) operand |
4147 | ||
4148 | Bound : Node_Id; | |
4149 | -- Temp variable used to hold a bound node | |
4150 | ||
4151 | Hbound : Uint; | |
4152 | -- High bound of base type of expression | |
4153 | ||
4154 | Lor : Uint; | |
4155 | Hir : Uint; | |
4156 | -- Refined values for low and high bounds, after tightening | |
4157 | ||
4158 | OK1 : Boolean; | |
4159 | -- Used in lower level calls to indicate if call succeeded | |
4160 | ||
4161 | Cindex : Cache_Index; | |
4162 | -- Used to search cache | |
ee6ba406 | 4163 | |
094ed68e | 4164 | Btyp : Entity_Id; |
4165 | -- Base type | |
4166 | ||
ee6ba406 | 4167 | function OK_Operands return Boolean; |
4168 | -- Used for binary operators. Determines the ranges of the left and | |
4169 | -- right operands, and if they are both OK, returns True, and puts | |
341bd953 | 4170 | -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left. |
ee6ba406 | 4171 | |
4172 | ----------------- | |
4173 | -- OK_Operands -- | |
4174 | ----------------- | |
4175 | ||
4176 | function OK_Operands return Boolean is | |
4177 | begin | |
9c486805 | 4178 | Determine_Range |
4179 | (Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid); | |
ee6ba406 | 4180 | |
4181 | if not OK1 then | |
4182 | return False; | |
4183 | end if; | |
4184 | ||
9c486805 | 4185 | Determine_Range |
4186 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
ee6ba406 | 4187 | return OK1; |
4188 | end OK_Operands; | |
4189 | ||
4190 | -- Start of processing for Determine_Range | |
4191 | ||
4192 | begin | |
e12b2502 | 4193 | -- Prevent junk warnings by initializing range variables |
4194 | ||
4195 | Lo := No_Uint; | |
4196 | Hi := No_Uint; | |
4197 | Lor := No_Uint; | |
4198 | Hir := No_Uint; | |
4199 | ||
87bdc21d | 4200 | -- For temporary constants internally generated to remove side effects |
4201 | -- we must use the corresponding expression to determine the range of | |
e12b2502 | 4202 | -- the expression. But note that the expander can also generate |
4203 | -- constants in other cases, including deferred constants. | |
87bdc21d | 4204 | |
4205 | if Is_Entity_Name (N) | |
4206 | and then Nkind (Parent (Entity (N))) = N_Object_Declaration | |
4207 | and then Ekind (Entity (N)) = E_Constant | |
4208 | and then Is_Internal_Name (Chars (Entity (N))) | |
4209 | then | |
e12b2502 | 4210 | if Present (Expression (Parent (Entity (N)))) then |
4211 | Determine_Range | |
4212 | (Expression (Parent (Entity (N))), OK, Lo, Hi, Assume_Valid); | |
87bdc21d | 4213 | |
e12b2502 | 4214 | elsif Present (Full_View (Entity (N))) then |
4215 | Determine_Range | |
4216 | (Expression (Parent (Full_View (Entity (N)))), | |
4217 | OK, Lo, Hi, Assume_Valid); | |
ee6ba406 | 4218 | |
e12b2502 | 4219 | else |
4220 | OK := False; | |
4221 | end if; | |
4222 | return; | |
4223 | end if; | |
ee6ba406 | 4224 | |
a781c0fc | 4225 | -- If type is not defined, we can't determine its range |
ee6ba406 | 4226 | |
a781c0fc | 4227 | if No (Typ) |
4228 | ||
4229 | -- We don't deal with anything except discrete types | |
4230 | ||
4231 | or else not Is_Discrete_Type (Typ) | |
4232 | ||
4233 | -- Ignore type for which an error has been posted, since range in | |
4234 | -- this case may well be a bogosity deriving from the error. Also | |
4235 | -- ignore if error posted on the reference node. | |
4236 | ||
4237 | or else Error_Posted (N) or else Error_Posted (Typ) | |
ee6ba406 | 4238 | then |
4239 | OK := False; | |
4240 | return; | |
4241 | end if; | |
4242 | ||
4243 | -- For all other cases, we can determine the range | |
4244 | ||
4245 | OK := True; | |
4246 | ||
feff2f05 | 4247 | -- If value is compile time known, then the possible range is the one |
39a0c1d3 | 4248 | -- value that we know this expression definitely has. |
ee6ba406 | 4249 | |
4250 | if Compile_Time_Known_Value (N) then | |
4251 | Lo := Expr_Value (N); | |
4252 | Hi := Lo; | |
4253 | return; | |
4254 | end if; | |
4255 | ||
4256 | -- Return if already in the cache | |
4257 | ||
4258 | Cindex := Cache_Index (N mod Cache_Size); | |
4259 | ||
9c486805 | 4260 | if Determine_Range_Cache_N (Cindex) = N |
4261 | and then | |
4262 | Determine_Range_Cache_V (Cindex) = Assume_Valid | |
4263 | then | |
ee6ba406 | 4264 | Lo := Determine_Range_Cache_Lo (Cindex); |
4265 | Hi := Determine_Range_Cache_Hi (Cindex); | |
4266 | return; | |
4267 | end if; | |
4268 | ||
feff2f05 | 4269 | -- Otherwise, start by finding the bounds of the type of the expression, |
4270 | -- the value cannot be outside this range (if it is, then we have an | |
4271 | -- overflow situation, which is a separate check, we are talking here | |
4272 | -- only about the expression value). | |
ee6ba406 | 4273 | |
341bd953 | 4274 | -- First a check, never try to find the bounds of a generic type, since |
4275 | -- these bounds are always junk values, and it is only valid to look at | |
4276 | -- the bounds in an instance. | |
4277 | ||
4278 | if Is_Generic_Type (Typ) then | |
4279 | OK := False; | |
4280 | return; | |
4281 | end if; | |
4282 | ||
9c486805 | 4283 | -- First step, change to use base type unless we know the value is valid |
e254d721 | 4284 | |
9c486805 | 4285 | if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N))) |
4286 | or else Assume_No_Invalid_Values | |
4287 | or else Assume_Valid | |
e254d721 | 4288 | then |
9c486805 | 4289 | null; |
4290 | else | |
4291 | Typ := Underlying_Type (Base_Type (Typ)); | |
e254d721 | 4292 | end if; |
4293 | ||
094ed68e | 4294 | -- Retrieve the base type. Handle the case where the base type is a |
4295 | -- private enumeration type. | |
4296 | ||
4297 | Btyp := Base_Type (Typ); | |
4298 | ||
4299 | if Is_Private_Type (Btyp) and then Present (Full_View (Btyp)) then | |
4300 | Btyp := Full_View (Btyp); | |
4301 | end if; | |
4302 | ||
feff2f05 | 4303 | -- We use the actual bound unless it is dynamic, in which case use the |
4304 | -- corresponding base type bound if possible. If we can't get a bound | |
4305 | -- then we figure we can't determine the range (a peculiar case, that | |
4306 | -- perhaps cannot happen, but there is no point in bombing in this | |
4307 | -- optimization circuit. | |
8880be85 | 4308 | |
4309 | -- First the low bound | |
ee6ba406 | 4310 | |
4311 | Bound := Type_Low_Bound (Typ); | |
4312 | ||
4313 | if Compile_Time_Known_Value (Bound) then | |
4314 | Lo := Expr_Value (Bound); | |
4315 | ||
094ed68e | 4316 | elsif Compile_Time_Known_Value (Type_Low_Bound (Btyp)) then |
4317 | Lo := Expr_Value (Type_Low_Bound (Btyp)); | |
ee6ba406 | 4318 | |
4319 | else | |
4320 | OK := False; | |
4321 | return; | |
4322 | end if; | |
4323 | ||
8880be85 | 4324 | -- Now the high bound |
4325 | ||
ee6ba406 | 4326 | Bound := Type_High_Bound (Typ); |
4327 | ||
8880be85 | 4328 | -- We need the high bound of the base type later on, and this should |
4329 | -- always be compile time known. Again, it is not clear that this | |
4330 | -- can ever be false, but no point in bombing. | |
ee6ba406 | 4331 | |
094ed68e | 4332 | if Compile_Time_Known_Value (Type_High_Bound (Btyp)) then |
4333 | Hbound := Expr_Value (Type_High_Bound (Btyp)); | |
ee6ba406 | 4334 | Hi := Hbound; |
4335 | ||
4336 | else | |
4337 | OK := False; | |
4338 | return; | |
4339 | end if; | |
4340 | ||
feff2f05 | 4341 | -- If we have a static subtype, then that may have a tighter bound so |
4342 | -- use the upper bound of the subtype instead in this case. | |
8880be85 | 4343 | |
4344 | if Compile_Time_Known_Value (Bound) then | |
4345 | Hi := Expr_Value (Bound); | |
4346 | end if; | |
4347 | ||
feff2f05 | 4348 | -- We may be able to refine this value in certain situations. If any |
4349 | -- refinement is possible, then Lor and Hir are set to possibly tighter | |
4350 | -- bounds, and OK1 is set to True. | |
ee6ba406 | 4351 | |
4352 | case Nkind (N) is | |
4353 | ||
4354 | -- For unary plus, result is limited by range of operand | |
4355 | ||
4356 | when N_Op_Plus => | |
9c486805 | 4357 | Determine_Range |
4358 | (Right_Opnd (N), OK1, Lor, Hir, Assume_Valid); | |
ee6ba406 | 4359 | |
4360 | -- For unary minus, determine range of operand, and negate it | |
4361 | ||
4362 | when N_Op_Minus => | |
9c486805 | 4363 | Determine_Range |
4364 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
ee6ba406 | 4365 | |
4366 | if OK1 then | |
4367 | Lor := -Hi_Right; | |
4368 | Hir := -Lo_Right; | |
4369 | end if; | |
4370 | ||
4371 | -- For binary addition, get range of each operand and do the | |
4372 | -- addition to get the result range. | |
4373 | ||
4374 | when N_Op_Add => | |
4375 | if OK_Operands then | |
4376 | Lor := Lo_Left + Lo_Right; | |
4377 | Hir := Hi_Left + Hi_Right; | |
4378 | end if; | |
4379 | ||
feff2f05 | 4380 | -- Division is tricky. The only case we consider is where the right |
4381 | -- operand is a positive constant, and in this case we simply divide | |
4382 | -- the bounds of the left operand | |
ee6ba406 | 4383 | |
4384 | when N_Op_Divide => | |
4385 | if OK_Operands then | |
4386 | if Lo_Right = Hi_Right | |
4387 | and then Lo_Right > 0 | |
4388 | then | |
4389 | Lor := Lo_Left / Lo_Right; | |
4390 | Hir := Hi_Left / Lo_Right; | |
ee6ba406 | 4391 | else |
4392 | OK1 := False; | |
4393 | end if; | |
4394 | end if; | |
4395 | ||
feff2f05 | 4396 | -- For binary subtraction, get range of each operand and do the worst |
4397 | -- case subtraction to get the result range. | |
ee6ba406 | 4398 | |
4399 | when N_Op_Subtract => | |
4400 | if OK_Operands then | |
4401 | Lor := Lo_Left - Hi_Right; | |
4402 | Hir := Hi_Left - Lo_Right; | |
4403 | end if; | |
4404 | ||
feff2f05 | 4405 | -- For MOD, if right operand is a positive constant, then result must |
4406 | -- be in the allowable range of mod results. | |
ee6ba406 | 4407 | |
4408 | when N_Op_Mod => | |
4409 | if OK_Operands then | |
9dfe12ae | 4410 | if Lo_Right = Hi_Right |
4411 | and then Lo_Right /= 0 | |
4412 | then | |
ee6ba406 | 4413 | if Lo_Right > 0 then |
4414 | Lor := Uint_0; | |
4415 | Hir := Lo_Right - 1; | |
4416 | ||
9dfe12ae | 4417 | else -- Lo_Right < 0 |
ee6ba406 | 4418 | Lor := Lo_Right + 1; |
4419 | Hir := Uint_0; | |
4420 | end if; | |
4421 | ||
4422 | else | |
4423 | OK1 := False; | |
4424 | end if; | |
4425 | end if; | |
4426 | ||
feff2f05 | 4427 | -- For REM, if right operand is a positive constant, then result must |
4428 | -- be in the allowable range of mod results. | |
ee6ba406 | 4429 | |
4430 | when N_Op_Rem => | |
4431 | if OK_Operands then | |
9dfe12ae | 4432 | if Lo_Right = Hi_Right |
4433 | and then Lo_Right /= 0 | |
4434 | then | |
ee6ba406 | 4435 | declare |
4436 | Dval : constant Uint := (abs Lo_Right) - 1; | |
4437 | ||
4438 | begin | |
4439 | -- The sign of the result depends on the sign of the | |
4440 | -- dividend (but not on the sign of the divisor, hence | |
4441 | -- the abs operation above). | |
4442 | ||
4443 | if Lo_Left < 0 then | |
4444 | Lor := -Dval; | |
4445 | else | |
4446 | Lor := Uint_0; | |
4447 | end if; | |
4448 | ||
4449 | if Hi_Left < 0 then | |
4450 | Hir := Uint_0; | |
4451 | else | |
4452 | Hir := Dval; | |
4453 | end if; | |
4454 | end; | |
4455 | ||
4456 | else | |
4457 | OK1 := False; | |
4458 | end if; | |
4459 | end if; | |
4460 | ||
4461 | -- Attribute reference cases | |
4462 | ||
4463 | when N_Attribute_Reference => | |
4464 | case Attribute_Name (N) is | |
4465 | ||
4466 | -- For Pos/Val attributes, we can refine the range using the | |
ddbf7f2e | 4467 | -- possible range of values of the attribute expression. |
ee6ba406 | 4468 | |
4469 | when Name_Pos | Name_Val => | |
9c486805 | 4470 | Determine_Range |
4471 | (First (Expressions (N)), OK1, Lor, Hir, Assume_Valid); | |
ee6ba406 | 4472 | |
4473 | -- For Length attribute, use the bounds of the corresponding | |
4474 | -- index type to refine the range. | |
4475 | ||
4476 | when Name_Length => | |
4477 | declare | |
4478 | Atyp : Entity_Id := Etype (Prefix (N)); | |
4479 | Inum : Nat; | |
4480 | Indx : Node_Id; | |
4481 | ||
4482 | LL, LU : Uint; | |
4483 | UL, UU : Uint; | |
4484 | ||
4485 | begin | |
4486 | if Is_Access_Type (Atyp) then | |
4487 | Atyp := Designated_Type (Atyp); | |
4488 | end if; | |
4489 | ||
4490 | -- For string literal, we know exact value | |
4491 | ||
4492 | if Ekind (Atyp) = E_String_Literal_Subtype then | |
4493 | OK := True; | |
4494 | Lo := String_Literal_Length (Atyp); | |
4495 | Hi := String_Literal_Length (Atyp); | |
4496 | return; | |
4497 | end if; | |
4498 | ||
4499 | -- Otherwise check for expression given | |
4500 | ||
4501 | if No (Expressions (N)) then | |
4502 | Inum := 1; | |
4503 | else | |
4504 | Inum := | |
4505 | UI_To_Int (Expr_Value (First (Expressions (N)))); | |
4506 | end if; | |
4507 | ||
4508 | Indx := First_Index (Atyp); | |
4509 | for J in 2 .. Inum loop | |
4510 | Indx := Next_Index (Indx); | |
4511 | end loop; | |
4512 | ||
9116df93 | 4513 | -- If the index type is a formal type or derived from |
c8da6114 | 4514 | -- one, the bounds are not static. |
4515 | ||
4516 | if Is_Generic_Type (Root_Type (Etype (Indx))) then | |
4517 | OK := False; | |
4518 | return; | |
4519 | end if; | |
4520 | ||
ee6ba406 | 4521 | Determine_Range |
9c486805 | 4522 | (Type_Low_Bound (Etype (Indx)), OK1, LL, LU, |
4523 | Assume_Valid); | |
ee6ba406 | 4524 | |
4525 | if OK1 then | |
4526 | Determine_Range | |
9c486805 | 4527 | (Type_High_Bound (Etype (Indx)), OK1, UL, UU, |
4528 | Assume_Valid); | |
ee6ba406 | 4529 | |
4530 | if OK1 then | |
4531 | ||
4532 | -- The maximum value for Length is the biggest | |
4533 | -- possible gap between the values of the bounds. | |
4534 | -- But of course, this value cannot be negative. | |
4535 | ||
9c486805 | 4536 | Hir := UI_Max (Uint_0, UU - LL + 1); |
ee6ba406 | 4537 | |
4538 | -- For constrained arrays, the minimum value for | |
4539 | -- Length is taken from the actual value of the | |
9116df93 | 4540 | -- bounds, since the index will be exactly of this |
4541 | -- subtype. | |
ee6ba406 | 4542 | |
4543 | if Is_Constrained (Atyp) then | |
9c486805 | 4544 | Lor := UI_Max (Uint_0, UL - LU + 1); |
ee6ba406 | 4545 | |
4546 | -- For an unconstrained array, the minimum value | |
4547 | -- for length is always zero. | |
4548 | ||
4549 | else | |
4550 | Lor := Uint_0; | |
4551 | end if; | |
4552 | end if; | |
4553 | end if; | |
4554 | end; | |
4555 | ||
4556 | -- No special handling for other attributes | |
9116df93 | 4557 | -- Probably more opportunities exist here??? |
ee6ba406 | 4558 | |
4559 | when others => | |
4560 | OK1 := False; | |
4561 | ||
4562 | end case; | |
4563 | ||
feff2f05 | 4564 | -- For type conversion from one discrete type to another, we can |
4565 | -- refine the range using the converted value. | |
ee6ba406 | 4566 | |
4567 | when N_Type_Conversion => | |
9c486805 | 4568 | Determine_Range (Expression (N), OK1, Lor, Hir, Assume_Valid); |
ee6ba406 | 4569 | |
4570 | -- Nothing special to do for all other expression kinds | |
4571 | ||
4572 | when others => | |
4573 | OK1 := False; | |
4574 | Lor := No_Uint; | |
4575 | Hir := No_Uint; | |
4576 | end case; | |
4577 | ||
9116df93 | 4578 | -- At this stage, if OK1 is true, then we know that the actual result of |
4579 | -- the computed expression is in the range Lor .. Hir. We can use this | |
4580 | -- to restrict the possible range of results. | |
ee6ba406 | 4581 | |
4582 | if OK1 then | |
4583 | ||
9116df93 | 4584 | -- If the refined value of the low bound is greater than the type |
7ac8c2b1 | 4585 | -- low bound, then reset it to the more restrictive value. However, |
9116df93 | 4586 | -- we do NOT do this for the case of a modular type where the |
4587 | -- possible upper bound on the value is above the base type high | |
4588 | -- bound, because that means the result could wrap. | |
ee6ba406 | 4589 | |
4590 | if Lor > Lo | |
9116df93 | 4591 | and then not (Is_Modular_Integer_Type (Typ) and then Hir > Hbound) |
ee6ba406 | 4592 | then |
4593 | Lo := Lor; | |
4594 | end if; | |
4595 | ||
9116df93 | 4596 | -- Similarly, if the refined value of the high bound is less than the |
4597 | -- value so far, then reset it to the more restrictive value. Again, | |
4598 | -- we do not do this if the refined low bound is negative for a | |
4599 | -- modular type, since this would wrap. | |
ee6ba406 | 4600 | |
4601 | if Hir < Hi | |
9116df93 | 4602 | and then not (Is_Modular_Integer_Type (Typ) and then Lor < Uint_0) |
ee6ba406 | 4603 | then |
4604 | Hi := Hir; | |
4605 | end if; | |
4606 | end if; | |
4607 | ||
4608 | -- Set cache entry for future call and we are all done | |
4609 | ||
4610 | Determine_Range_Cache_N (Cindex) := N; | |
9c486805 | 4611 | Determine_Range_Cache_V (Cindex) := Assume_Valid; |
ee6ba406 | 4612 | Determine_Range_Cache_Lo (Cindex) := Lo; |
4613 | Determine_Range_Cache_Hi (Cindex) := Hi; | |
4614 | return; | |
4615 | ||
9116df93 | 4616 | -- If any exception occurs, it means that we have some bug in the compiler, |
4617 | -- possibly triggered by a previous error, or by some unforeseen peculiar | |
ee6ba406 | 4618 | -- occurrence. However, this is only an optimization attempt, so there is |
4619 | -- really no point in crashing the compiler. Instead we just decide, too | |
4620 | -- bad, we can't figure out a range in this case after all. | |
4621 | ||
4622 | exception | |
4623 | when others => | |
4624 | ||
4625 | -- Debug flag K disables this behavior (useful for debugging) | |
4626 | ||
4627 | if Debug_Flag_K then | |
4628 | raise; | |
4629 | else | |
4630 | OK := False; | |
4631 | Lo := No_Uint; | |
4632 | Hi := No_Uint; | |
4633 | return; | |
4634 | end if; | |
ee6ba406 | 4635 | end Determine_Range; |
4636 | ||
7ac8c2b1 | 4637 | ----------------------- |
4638 | -- Determine_Range_R -- | |
4639 | ----------------------- | |
4640 | ||
4641 | procedure Determine_Range_R | |
4642 | (N : Node_Id; | |
4643 | OK : out Boolean; | |
4644 | Lo : out Ureal; | |
4645 | Hi : out Ureal; | |
4646 | Assume_Valid : Boolean := False) | |
4647 | is | |
4648 | Typ : Entity_Id := Etype (N); | |
4649 | -- Type to use, may get reset to base type for possibly invalid entity | |
4650 | ||
4651 | Lo_Left : Ureal; | |
4652 | Hi_Left : Ureal; | |
4653 | -- Lo and Hi bounds of left operand | |
4654 | ||
4655 | Lo_Right : Ureal; | |
4656 | Hi_Right : Ureal; | |
4657 | -- Lo and Hi bounds of right (or only) operand | |
4658 | ||
4659 | Bound : Node_Id; | |
4660 | -- Temp variable used to hold a bound node | |
4661 | ||
4662 | Hbound : Ureal; | |
4663 | -- High bound of base type of expression | |
4664 | ||
4665 | Lor : Ureal; | |
4666 | Hir : Ureal; | |
4667 | -- Refined values for low and high bounds, after tightening | |
4668 | ||
4669 | OK1 : Boolean; | |
4670 | -- Used in lower level calls to indicate if call succeeded | |
4671 | ||
4672 | Cindex : Cache_Index; | |
4673 | -- Used to search cache | |
4674 | ||
4675 | Btyp : Entity_Id; | |
4676 | -- Base type | |
4677 | ||
4678 | function OK_Operands return Boolean; | |
4679 | -- Used for binary operators. Determines the ranges of the left and | |
4680 | -- right operands, and if they are both OK, returns True, and puts | |
4681 | -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left. | |
4682 | ||
4683 | function Round_Machine (B : Ureal) return Ureal; | |
4684 | -- B is a real bound. Round it using mode Round_Even. | |
4685 | ||
4686 | ----------------- | |
4687 | -- OK_Operands -- | |
4688 | ----------------- | |
4689 | ||
4690 | function OK_Operands return Boolean is | |
4691 | begin | |
4692 | Determine_Range_R | |
4693 | (Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid); | |
4694 | ||
4695 | if not OK1 then | |
4696 | return False; | |
4697 | end if; | |
4698 | ||
4699 | Determine_Range_R | |
4700 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
4701 | return OK1; | |
4702 | end OK_Operands; | |
4703 | ||
4704 | ------------------- | |
4705 | -- Round_Machine -- | |
4706 | ------------------- | |
4707 | ||
4708 | function Round_Machine (B : Ureal) return Ureal is | |
4709 | begin | |
4710 | return Machine (Typ, B, Round_Even, N); | |
4711 | end Round_Machine; | |
4712 | ||
4713 | -- Start of processing for Determine_Range_R | |
4714 | ||
4715 | begin | |
4716 | -- Prevent junk warnings by initializing range variables | |
4717 | ||
4718 | Lo := No_Ureal; | |
4719 | Hi := No_Ureal; | |
4720 | Lor := No_Ureal; | |
4721 | Hir := No_Ureal; | |
4722 | ||
4723 | -- For temporary constants internally generated to remove side effects | |
4724 | -- we must use the corresponding expression to determine the range of | |
4725 | -- the expression. But note that the expander can also generate | |
4726 | -- constants in other cases, including deferred constants. | |
4727 | ||
4728 | if Is_Entity_Name (N) | |
4729 | and then Nkind (Parent (Entity (N))) = N_Object_Declaration | |
4730 | and then Ekind (Entity (N)) = E_Constant | |
4731 | and then Is_Internal_Name (Chars (Entity (N))) | |
4732 | then | |
4733 | if Present (Expression (Parent (Entity (N)))) then | |
4734 | Determine_Range_R | |
4735 | (Expression (Parent (Entity (N))), OK, Lo, Hi, Assume_Valid); | |
4736 | ||
4737 | elsif Present (Full_View (Entity (N))) then | |
4738 | Determine_Range_R | |
4739 | (Expression (Parent (Full_View (Entity (N)))), | |
4740 | OK, Lo, Hi, Assume_Valid); | |
4741 | ||
4742 | else | |
4743 | OK := False; | |
4744 | end if; | |
4c1c7f3f | 4745 | |
7ac8c2b1 | 4746 | return; |
4747 | end if; | |
4748 | ||
4749 | -- If type is not defined, we can't determine its range | |
4750 | ||
4751 | if No (Typ) | |
4752 | ||
4753 | -- We don't deal with anything except IEEE floating-point types | |
4754 | ||
4755 | or else not Is_Floating_Point_Type (Typ) | |
4756 | or else Float_Rep (Typ) /= IEEE_Binary | |
4757 | ||
4758 | -- Ignore type for which an error has been posted, since range in | |
4759 | -- this case may well be a bogosity deriving from the error. Also | |
4760 | -- ignore if error posted on the reference node. | |
4761 | ||
4762 | or else Error_Posted (N) or else Error_Posted (Typ) | |
4763 | then | |
4764 | OK := False; | |
4765 | return; | |
4766 | end if; | |
4767 | ||
4768 | -- For all other cases, we can determine the range | |
4769 | ||
4770 | OK := True; | |
4771 | ||
4772 | -- If value is compile time known, then the possible range is the one | |
4773 | -- value that we know this expression definitely has. | |
4774 | ||
4775 | if Compile_Time_Known_Value (N) then | |
4776 | Lo := Expr_Value_R (N); | |
4777 | Hi := Lo; | |
4778 | return; | |
4779 | end if; | |
4780 | ||
4781 | -- Return if already in the cache | |
4782 | ||
4783 | Cindex := Cache_Index (N mod Cache_Size); | |
4784 | ||
4785 | if Determine_Range_Cache_N (Cindex) = N | |
4786 | and then | |
4787 | Determine_Range_Cache_V (Cindex) = Assume_Valid | |
4788 | then | |
4789 | Lo := Determine_Range_Cache_Lo_R (Cindex); | |
4790 | Hi := Determine_Range_Cache_Hi_R (Cindex); | |
4791 | return; | |
4792 | end if; | |
4793 | ||
4794 | -- Otherwise, start by finding the bounds of the type of the expression, | |
4795 | -- the value cannot be outside this range (if it is, then we have an | |
4796 | -- overflow situation, which is a separate check, we are talking here | |
4797 | -- only about the expression value). | |
4798 | ||
4799 | -- First a check, never try to find the bounds of a generic type, since | |
4800 | -- these bounds are always junk values, and it is only valid to look at | |
4801 | -- the bounds in an instance. | |
4802 | ||
4803 | if Is_Generic_Type (Typ) then | |
4804 | OK := False; | |
4805 | return; | |
4806 | end if; | |
4807 | ||
4808 | -- First step, change to use base type unless we know the value is valid | |
4809 | ||
4810 | if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N))) | |
4811 | or else Assume_No_Invalid_Values | |
4812 | or else Assume_Valid | |
4813 | then | |
4814 | null; | |
4815 | else | |
4816 | Typ := Underlying_Type (Base_Type (Typ)); | |
4817 | end if; | |
4818 | ||
4819 | -- Retrieve the base type. Handle the case where the base type is a | |
4820 | -- private type. | |
4821 | ||
4822 | Btyp := Base_Type (Typ); | |
4823 | ||
4824 | if Is_Private_Type (Btyp) and then Present (Full_View (Btyp)) then | |
4825 | Btyp := Full_View (Btyp); | |
4826 | end if; | |
4827 | ||
4828 | -- We use the actual bound unless it is dynamic, in which case use the | |
4829 | -- corresponding base type bound if possible. If we can't get a bound | |
4830 | -- then we figure we can't determine the range (a peculiar case, that | |
4831 | -- perhaps cannot happen, but there is no point in bombing in this | |
4832 | -- optimization circuit). | |
4833 | ||
4834 | -- First the low bound | |
4835 | ||
4836 | Bound := Type_Low_Bound (Typ); | |
4837 | ||
4838 | if Compile_Time_Known_Value (Bound) then | |
4839 | Lo := Expr_Value_R (Bound); | |
4840 | ||
4841 | elsif Compile_Time_Known_Value (Type_Low_Bound (Btyp)) then | |
4842 | Lo := Expr_Value_R (Type_Low_Bound (Btyp)); | |
4843 | ||
4844 | else | |
4845 | OK := False; | |
4846 | return; | |
4847 | end if; | |
4848 | ||
4849 | -- Now the high bound | |
4850 | ||
4851 | Bound := Type_High_Bound (Typ); | |
4852 | ||
4853 | -- We need the high bound of the base type later on, and this should | |
4854 | -- always be compile time known. Again, it is not clear that this | |
4855 | -- can ever be false, but no point in bombing. | |
4856 | ||
4857 | if Compile_Time_Known_Value (Type_High_Bound (Btyp)) then | |
4858 | Hbound := Expr_Value_R (Type_High_Bound (Btyp)); | |
4859 | Hi := Hbound; | |
4860 | ||
4861 | else | |
4862 | OK := False; | |
4863 | return; | |
4864 | end if; | |
4865 | ||
4866 | -- If we have a static subtype, then that may have a tighter bound so | |
4867 | -- use the upper bound of the subtype instead in this case. | |
4868 | ||
4869 | if Compile_Time_Known_Value (Bound) then | |
4870 | Hi := Expr_Value_R (Bound); | |
4871 | end if; | |
4872 | ||
4873 | -- We may be able to refine this value in certain situations. If any | |
4874 | -- refinement is possible, then Lor and Hir are set to possibly tighter | |
4875 | -- bounds, and OK1 is set to True. | |
4876 | ||
4877 | case Nkind (N) is | |
4878 | ||
4879 | -- For unary plus, result is limited by range of operand | |
4880 | ||
4881 | when N_Op_Plus => | |
4882 | Determine_Range_R | |
4883 | (Right_Opnd (N), OK1, Lor, Hir, Assume_Valid); | |
4884 | ||
4885 | -- For unary minus, determine range of operand, and negate it | |
4886 | ||
4887 | when N_Op_Minus => | |
4888 | Determine_Range_R | |
4889 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
4890 | ||
4891 | if OK1 then | |
4892 | Lor := -Hi_Right; | |
4893 | Hir := -Lo_Right; | |
4894 | end if; | |
4895 | ||
4896 | -- For binary addition, get range of each operand and do the | |
4897 | -- addition to get the result range. | |
4898 | ||
4899 | when N_Op_Add => | |
4900 | if OK_Operands then | |
4901 | Lor := Round_Machine (Lo_Left + Lo_Right); | |
4902 | Hir := Round_Machine (Hi_Left + Hi_Right); | |
4903 | end if; | |
4904 | ||
4905 | -- For binary subtraction, get range of each operand and do the worst | |
4906 | -- case subtraction to get the result range. | |
4907 | ||
4908 | when N_Op_Subtract => | |
4909 | if OK_Operands then | |
4910 | Lor := Round_Machine (Lo_Left - Hi_Right); | |
4911 | Hir := Round_Machine (Hi_Left - Lo_Right); | |
4912 | end if; | |
4913 | ||
4914 | -- For multiplication, get range of each operand and do the | |
4915 | -- four multiplications to get the result range. | |
4916 | ||
4917 | when N_Op_Multiply => | |
4918 | if OK_Operands then | |
4919 | declare | |
4920 | M1 : constant Ureal := Round_Machine (Lo_Left * Lo_Right); | |
4921 | M2 : constant Ureal := Round_Machine (Lo_Left * Hi_Right); | |
4922 | M3 : constant Ureal := Round_Machine (Hi_Left * Lo_Right); | |
4923 | M4 : constant Ureal := Round_Machine (Hi_Left * Hi_Right); | |
4924 | begin | |
4925 | Lor := UR_Min (UR_Min (M1, M2), UR_Min (M3, M4)); | |
4926 | Hir := UR_Max (UR_Max (M1, M2), UR_Max (M3, M4)); | |
4927 | end; | |
4928 | end if; | |
4929 | ||
4930 | -- For division, consider separately the cases where the right | |
4931 | -- operand is positive or negative. Otherwise, the right operand | |
4932 | -- can be arbitrarily close to zero, so the result is likely to | |
4933 | -- be unbounded in one direction, do not attempt to compute it. | |
4934 | ||
4935 | when N_Op_Divide => | |
4936 | if OK_Operands then | |
4937 | ||
4938 | -- Right operand is positive | |
4939 | ||
4940 | if Lo_Right > Ureal_0 then | |
4941 | ||
4942 | -- If the low bound of the left operand is negative, obtain | |
4943 | -- the overall low bound by dividing it by the smallest | |
4944 | -- value of the right operand, and otherwise by the largest | |
4945 | -- value of the right operand. | |
4946 | ||
4947 | if Lo_Left < Ureal_0 then | |
4948 | Lor := Round_Machine (Lo_Left / Lo_Right); | |
4949 | else | |
4950 | Lor := Round_Machine (Lo_Left / Hi_Right); | |
4951 | end if; | |
4952 | ||
4953 | -- If the high bound of the left operand is negative, obtain | |
4954 | -- the overall high bound by dividing it by the largest | |
4955 | -- value of the right operand, and otherwise by the | |
4956 | -- smallest value of the right operand. | |
4957 | ||
4958 | if Hi_Left < Ureal_0 then | |
4959 | Hir := Round_Machine (Hi_Left / Hi_Right); | |
4960 | else | |
4961 | Hir := Round_Machine (Hi_Left / Lo_Right); | |
4962 | end if; | |
4963 | ||
4964 | -- Right operand is negative | |
4965 | ||
4966 | elsif Hi_Right < Ureal_0 then | |
4967 | ||
4968 | -- If the low bound of the left operand is negative, obtain | |
4969 | -- the overall low bound by dividing it by the largest | |
4970 | -- value of the right operand, and otherwise by the smallest | |
4971 | -- value of the right operand. | |
4972 | ||
4973 | if Lo_Left < Ureal_0 then | |
4974 | Lor := Round_Machine (Lo_Left / Hi_Right); | |
4975 | else | |
4976 | Lor := Round_Machine (Lo_Left / Lo_Right); | |
4977 | end if; | |
4978 | ||
4979 | -- If the high bound of the left operand is negative, obtain | |
4980 | -- the overall high bound by dividing it by the smallest | |
4981 | -- value of the right operand, and otherwise by the | |
4982 | -- largest value of the right operand. | |
4983 | ||
4984 | if Hi_Left < Ureal_0 then | |
4985 | Hir := Round_Machine (Hi_Left / Lo_Right); | |
4986 | else | |
4987 | Hir := Round_Machine (Hi_Left / Hi_Right); | |
4988 | end if; | |
4989 | ||
4990 | else | |
4991 | OK1 := False; | |
4992 | end if; | |
4993 | end if; | |
4994 | ||
4995 | -- For type conversion from one floating-point type to another, we | |
4996 | -- can refine the range using the converted value. | |
4997 | ||
4998 | when N_Type_Conversion => | |
4999 | Determine_Range_R (Expression (N), OK1, Lor, Hir, Assume_Valid); | |
5000 | ||
5001 | -- Nothing special to do for all other expression kinds | |
5002 | ||
5003 | when others => | |
5004 | OK1 := False; | |
5005 | Lor := No_Ureal; | |
5006 | Hir := No_Ureal; | |
5007 | end case; | |
5008 | ||
5009 | -- At this stage, if OK1 is true, then we know that the actual result of | |
5010 | -- the computed expression is in the range Lor .. Hir. We can use this | |
5011 | -- to restrict the possible range of results. | |
5012 | ||
5013 | if OK1 then | |
5014 | ||
5015 | -- If the refined value of the low bound is greater than the type | |
5016 | -- low bound, then reset it to the more restrictive value. | |
5017 | ||
5018 | if Lor > Lo then | |
5019 | Lo := Lor; | |
5020 | end if; | |
5021 | ||
5022 | -- Similarly, if the refined value of the high bound is less than the | |
5023 | -- value so far, then reset it to the more restrictive value. | |
5024 | ||
5025 | if Hir < Hi then | |
5026 | Hi := Hir; | |
5027 | end if; | |
5028 | end if; | |
5029 | ||
5030 | -- Set cache entry for future call and we are all done | |
5031 | ||
5032 | Determine_Range_Cache_N (Cindex) := N; | |
5033 | Determine_Range_Cache_V (Cindex) := Assume_Valid; | |
5034 | Determine_Range_Cache_Lo_R (Cindex) := Lo; | |
5035 | Determine_Range_Cache_Hi_R (Cindex) := Hi; | |
5036 | return; | |
5037 | ||
5038 | -- If any exception occurs, it means that we have some bug in the compiler, | |
5039 | -- possibly triggered by a previous error, or by some unforeseen peculiar | |
5040 | -- occurrence. However, this is only an optimization attempt, so there is | |
5041 | -- really no point in crashing the compiler. Instead we just decide, too | |
5042 | -- bad, we can't figure out a range in this case after all. | |
5043 | ||
5044 | exception | |
5045 | when others => | |
5046 | ||
5047 | -- Debug flag K disables this behavior (useful for debugging) | |
5048 | ||
5049 | if Debug_Flag_K then | |
5050 | raise; | |
5051 | else | |
5052 | OK := False; | |
5053 | Lo := No_Ureal; | |
5054 | Hi := No_Ureal; | |
5055 | return; | |
5056 | end if; | |
5057 | end Determine_Range_R; | |
5058 | ||
ee6ba406 | 5059 | ------------------------------------ |
5060 | -- Discriminant_Checks_Suppressed -- | |
5061 | ------------------------------------ | |
5062 | ||
5063 | function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5064 | begin | |
9dfe12ae | 5065 | if Present (E) then |
5066 | if Is_Unchecked_Union (E) then | |
5067 | return True; | |
5068 | elsif Checks_May_Be_Suppressed (E) then | |
5069 | return Is_Check_Suppressed (E, Discriminant_Check); | |
5070 | end if; | |
5071 | end if; | |
5072 | ||
fafc6b97 | 5073 | return Scope_Suppress.Suppress (Discriminant_Check); |
ee6ba406 | 5074 | end Discriminant_Checks_Suppressed; |
5075 | ||
5076 | -------------------------------- | |
5077 | -- Division_Checks_Suppressed -- | |
5078 | -------------------------------- | |
5079 | ||
5080 | function Division_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5081 | begin | |
9dfe12ae | 5082 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
5083 | return Is_Check_Suppressed (E, Division_Check); | |
5084 | else | |
fafc6b97 | 5085 | return Scope_Suppress.Suppress (Division_Check); |
9dfe12ae | 5086 | end if; |
ee6ba406 | 5087 | end Division_Checks_Suppressed; |
5088 | ||
fa771c05 | 5089 | -------------------------------------- |
5090 | -- Duplicated_Tag_Checks_Suppressed -- | |
5091 | -------------------------------------- | |
5092 | ||
5093 | function Duplicated_Tag_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5094 | begin | |
5095 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
5096 | return Is_Check_Suppressed (E, Duplicated_Tag_Check); | |
5097 | else | |
5098 | return Scope_Suppress.Suppress (Duplicated_Tag_Check); | |
5099 | end if; | |
5100 | end Duplicated_Tag_Checks_Suppressed; | |
5101 | ||
ee6ba406 | 5102 | ----------------------------------- |
5103 | -- Elaboration_Checks_Suppressed -- | |
5104 | ----------------------------------- | |
5105 | ||
5106 | function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5107 | begin | |
38f5559f | 5108 | -- The complication in this routine is that if we are in the dynamic |
5109 | -- model of elaboration, we also check All_Checks, since All_Checks | |
5110 | -- does not set Elaboration_Check explicitly. | |
5111 | ||
9dfe12ae | 5112 | if Present (E) then |
5113 | if Kill_Elaboration_Checks (E) then | |
5114 | return True; | |
38f5559f | 5115 | |
9dfe12ae | 5116 | elsif Checks_May_Be_Suppressed (E) then |
38f5559f | 5117 | if Is_Check_Suppressed (E, Elaboration_Check) then |
5118 | return True; | |
5119 | elsif Dynamic_Elaboration_Checks then | |
5120 | return Is_Check_Suppressed (E, All_Checks); | |
5121 | else | |
5122 | return False; | |
5123 | end if; | |
9dfe12ae | 5124 | end if; |
5125 | end if; | |
5126 | ||
fafc6b97 | 5127 | if Scope_Suppress.Suppress (Elaboration_Check) then |
38f5559f | 5128 | return True; |
5129 | elsif Dynamic_Elaboration_Checks then | |
fafc6b97 | 5130 | return Scope_Suppress.Suppress (All_Checks); |
38f5559f | 5131 | else |
5132 | return False; | |
5133 | end if; | |
ee6ba406 | 5134 | end Elaboration_Checks_Suppressed; |
5135 | ||
9dfe12ae | 5136 | --------------------------- |
5137 | -- Enable_Overflow_Check -- | |
5138 | --------------------------- | |
5139 | ||
5140 | procedure Enable_Overflow_Check (N : Node_Id) is | |
4c1c7f3f | 5141 | Typ : constant Entity_Id := Base_Type (Etype (N)); |
db415383 | 5142 | Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
3cce7f32 | 5143 | Chk : Nat; |
5144 | OK : Boolean; | |
5145 | Ent : Entity_Id; | |
5146 | Ofs : Uint; | |
5147 | Lo : Uint; | |
5148 | Hi : Uint; | |
ee6ba406 | 5149 | |
f3ccbbb3 | 5150 | Do_Ovflow_Check : Boolean; |
5151 | ||
ee6ba406 | 5152 | begin |
9dfe12ae | 5153 | if Debug_Flag_CC then |
5154 | w ("Enable_Overflow_Check for node ", Int (N)); | |
5155 | Write_Str (" Source location = "); | |
5156 | wl (Sloc (N)); | |
00c403ee | 5157 | pg (Union_Id (N)); |
ee6ba406 | 5158 | end if; |
ee6ba406 | 5159 | |
75209ec5 | 5160 | -- No check if overflow checks suppressed for type of node |
5161 | ||
0df9d43f | 5162 | if Overflow_Checks_Suppressed (Etype (N)) then |
75209ec5 | 5163 | return; |
5164 | ||
49260fa5 | 5165 | -- Nothing to do for unsigned integer types, which do not overflow |
5166 | ||
5167 | elsif Is_Modular_Integer_Type (Typ) then | |
5168 | return; | |
3cce7f32 | 5169 | end if; |
5170 | ||
0df9d43f | 5171 | -- This is the point at which processing for STRICT mode diverges |
21a55437 | 5172 | -- from processing for MINIMIZED/ELIMINATED modes. This divergence is |
5173 | -- probably more extreme that it needs to be, but what is going on here | |
5174 | -- is that when we introduced MINIMIZED/ELIMINATED modes, we wanted | |
0df9d43f | 5175 | -- to leave the processing for STRICT mode untouched. There were |
21a55437 | 5176 | -- two reasons for this. First it avoided any incompatible change of |
0df9d43f | 5177 | -- behavior. Second, it guaranteed that STRICT mode continued to be |
21a55437 | 5178 | -- legacy reliable. |
3cce7f32 | 5179 | |
0df9d43f | 5180 | -- The big difference is that in STRICT mode there is a fair amount of |
3cce7f32 | 5181 | -- circuitry to try to avoid setting the Do_Overflow_Check flag if we |
5182 | -- know that no check is needed. We skip all that in the two new modes, | |
5183 | -- since really overflow checking happens over a whole subtree, and we | |
5184 | -- do the corresponding optimizations later on when applying the checks. | |
5185 | ||
5186 | if Mode in Minimized_Or_Eliminated then | |
0df9d43f | 5187 | if not (Overflow_Checks_Suppressed (Etype (N))) |
5188 | and then not (Is_Entity_Name (N) | |
5189 | and then Overflow_Checks_Suppressed (Entity (N))) | |
5190 | then | |
5191 | Activate_Overflow_Check (N); | |
5192 | end if; | |
3cce7f32 | 5193 | |
5194 | if Debug_Flag_CC then | |
5195 | w ("Minimized/Eliminated mode"); | |
5196 | end if; | |
5197 | ||
5198 | return; | |
5199 | end if; | |
5200 | ||
0df9d43f | 5201 | -- Remainder of processing is for STRICT case, and is unchanged from |
691fe9e0 | 5202 | -- earlier versions preceding the addition of MINIMIZED/ELIMINATED. |
49260fa5 | 5203 | |
feff2f05 | 5204 | -- Nothing to do if the range of the result is known OK. We skip this |
5205 | -- for conversions, since the caller already did the check, and in any | |
5206 | -- case the condition for deleting the check for a type conversion is | |
cc60bd16 | 5207 | -- different. |
ee6ba406 | 5208 | |
3cce7f32 | 5209 | if Nkind (N) /= N_Type_Conversion then |
9c486805 | 5210 | Determine_Range (N, OK, Lo, Hi, Assume_Valid => True); |
ee6ba406 | 5211 | |
cc60bd16 | 5212 | -- Note in the test below that we assume that the range is not OK |
5213 | -- if a bound of the range is equal to that of the type. That's not | |
5214 | -- quite accurate but we do this for the following reasons: | |
ee6ba406 | 5215 | |
9dfe12ae | 5216 | -- a) The way that Determine_Range works, it will typically report |
5217 | -- the bounds of the value as being equal to the bounds of the | |
5218 | -- type, because it either can't tell anything more precise, or | |
5219 | -- does not think it is worth the effort to be more precise. | |
ee6ba406 | 5220 | |
9dfe12ae | 5221 | -- b) It is very unusual to have a situation in which this would |
5222 | -- generate an unnecessary overflow check (an example would be | |
5223 | -- a subtype with a range 0 .. Integer'Last - 1 to which the | |
cc60bd16 | 5224 | -- literal value one is added). |
ee6ba406 | 5225 | |
9dfe12ae | 5226 | -- c) The alternative is a lot of special casing in this routine |
5227 | -- which would partially duplicate Determine_Range processing. | |
ee6ba406 | 5228 | |
f3ccbbb3 | 5229 | if OK then |
5230 | Do_Ovflow_Check := True; | |
5231 | ||
5232 | -- Note that the following checks are quite deliberately > and < | |
5233 | -- rather than >= and <= as explained above. | |
5234 | ||
5235 | if Lo > Expr_Value (Type_Low_Bound (Typ)) | |
5236 | and then | |
5237 | Hi < Expr_Value (Type_High_Bound (Typ)) | |
5238 | then | |
5239 | Do_Ovflow_Check := False; | |
5240 | ||
5241 | -- Despite the comments above, it is worth dealing specially with | |
5242 | -- division specially. The only case where integer division can | |
5243 | -- overflow is (largest negative number) / (-1). So we will do | |
5244 | -- an extra range analysis to see if this is possible. | |
5245 | ||
5246 | elsif Nkind (N) = N_Op_Divide then | |
5247 | Determine_Range | |
5248 | (Left_Opnd (N), OK, Lo, Hi, Assume_Valid => True); | |
5249 | ||
5250 | if OK and then Lo > Expr_Value (Type_Low_Bound (Typ)) then | |
5251 | Do_Ovflow_Check := False; | |
5252 | ||
5253 | else | |
5254 | Determine_Range | |
5255 | (Right_Opnd (N), OK, Lo, Hi, Assume_Valid => True); | |
5256 | ||
5257 | if OK and then (Lo > Uint_Minus_1 | |
5258 | or else | |
5259 | Hi < Uint_Minus_1) | |
5260 | then | |
5261 | Do_Ovflow_Check := False; | |
5262 | end if; | |
5263 | end if; | |
9dfe12ae | 5264 | end if; |
5265 | ||
f3ccbbb3 | 5266 | -- If no overflow check required, we are done |
5267 | ||
5268 | if not Do_Ovflow_Check then | |
5269 | if Debug_Flag_CC then | |
5270 | w ("No overflow check required"); | |
5271 | end if; | |
5272 | ||
5273 | return; | |
5274 | end if; | |
9dfe12ae | 5275 | end if; |
5276 | end if; | |
5277 | ||
feff2f05 | 5278 | -- If not in optimizing mode, set flag and we are done. We are also done |
5279 | -- (and just set the flag) if the type is not a discrete type, since it | |
5280 | -- is not worth the effort to eliminate checks for other than discrete | |
5281 | -- types. In addition, we take this same path if we have stored the | |
5282 | -- maximum number of checks possible already (a very unlikely situation, | |
39a0c1d3 | 5283 | -- but we do not want to blow up). |
9dfe12ae | 5284 | |
5285 | if Optimization_Level = 0 | |
5286 | or else not Is_Discrete_Type (Etype (N)) | |
5287 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 5288 | then |
00c403ee | 5289 | Activate_Overflow_Check (N); |
9dfe12ae | 5290 | |
5291 | if Debug_Flag_CC then | |
5292 | w ("Optimization off"); | |
5293 | end if; | |
5294 | ||
ee6ba406 | 5295 | return; |
9dfe12ae | 5296 | end if; |
ee6ba406 | 5297 | |
9dfe12ae | 5298 | -- Otherwise evaluate and check the expression |
5299 | ||
5300 | Find_Check | |
5301 | (Expr => N, | |
5302 | Check_Type => 'O', | |
5303 | Target_Type => Empty, | |
5304 | Entry_OK => OK, | |
5305 | Check_Num => Chk, | |
5306 | Ent => Ent, | |
5307 | Ofs => Ofs); | |
5308 | ||
5309 | if Debug_Flag_CC then | |
5310 | w ("Called Find_Check"); | |
5311 | w (" OK = ", OK); | |
5312 | ||
5313 | if OK then | |
5314 | w (" Check_Num = ", Chk); | |
5315 | w (" Ent = ", Int (Ent)); | |
5316 | Write_Str (" Ofs = "); | |
5317 | pid (Ofs); | |
5318 | end if; | |
5319 | end if; | |
ee6ba406 | 5320 | |
9dfe12ae | 5321 | -- If check is not of form to optimize, then set flag and we are done |
5322 | ||
5323 | if not OK then | |
00c403ee | 5324 | Activate_Overflow_Check (N); |
ee6ba406 | 5325 | return; |
9dfe12ae | 5326 | end if; |
ee6ba406 | 5327 | |
9dfe12ae | 5328 | -- If check is already performed, then return without setting flag |
5329 | ||
5330 | if Chk /= 0 then | |
5331 | if Debug_Flag_CC then | |
5332 | w ("Check suppressed!"); | |
5333 | end if; | |
ee6ba406 | 5334 | |
ee6ba406 | 5335 | return; |
9dfe12ae | 5336 | end if; |
ee6ba406 | 5337 | |
9dfe12ae | 5338 | -- Here we will make a new entry for the new check |
5339 | ||
00c403ee | 5340 | Activate_Overflow_Check (N); |
9dfe12ae | 5341 | Num_Saved_Checks := Num_Saved_Checks + 1; |
5342 | Saved_Checks (Num_Saved_Checks) := | |
5343 | (Killed => False, | |
5344 | Entity => Ent, | |
5345 | Offset => Ofs, | |
5346 | Check_Type => 'O', | |
5347 | Target_Type => Empty); | |
5348 | ||
5349 | if Debug_Flag_CC then | |
5350 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
5351 | w (" Entity = ", Int (Ent)); | |
5352 | Write_Str (" Offset = "); | |
5353 | pid (Ofs); | |
5354 | w (" Check_Type = O"); | |
5355 | w (" Target_Type = Empty"); | |
5356 | end if; | |
ee6ba406 | 5357 | |
feff2f05 | 5358 | -- If we get an exception, then something went wrong, probably because of |
20cf157b | 5359 | -- an error in the structure of the tree due to an incorrect program. Or |
5360 | -- it may be a bug in the optimization circuit. In either case the safest | |
feff2f05 | 5361 | -- thing is simply to set the check flag unconditionally. |
9dfe12ae | 5362 | |
5363 | exception | |
5364 | when others => | |
00c403ee | 5365 | Activate_Overflow_Check (N); |
9dfe12ae | 5366 | |
5367 | if Debug_Flag_CC then | |
5368 | w (" exception occurred, overflow flag set"); | |
5369 | end if; | |
5370 | ||
5371 | return; | |
5372 | end Enable_Overflow_Check; | |
5373 | ||
5374 | ------------------------ | |
5375 | -- Enable_Range_Check -- | |
5376 | ------------------------ | |
5377 | ||
5378 | procedure Enable_Range_Check (N : Node_Id) is | |
5379 | Chk : Nat; | |
5380 | OK : Boolean; | |
5381 | Ent : Entity_Id; | |
5382 | Ofs : Uint; | |
5383 | Ttyp : Entity_Id; | |
5384 | P : Node_Id; | |
5385 | ||
5386 | begin | |
feff2f05 | 5387 | -- Return if unchecked type conversion with range check killed. In this |
39a0c1d3 | 5388 | -- case we never set the flag (that's what Kill_Range_Check is about). |
9dfe12ae | 5389 | |
5390 | if Nkind (N) = N_Unchecked_Type_Conversion | |
5391 | and then Kill_Range_Check (N) | |
ee6ba406 | 5392 | then |
5393 | return; | |
9dfe12ae | 5394 | end if; |
ee6ba406 | 5395 | |
55e8372b | 5396 | -- Do not set range check flag if parent is assignment statement or |
5397 | -- object declaration with Suppress_Assignment_Checks flag set | |
5398 | ||
5399 | if Nkind_In (Parent (N), N_Assignment_Statement, N_Object_Declaration) | |
5400 | and then Suppress_Assignment_Checks (Parent (N)) | |
5401 | then | |
5402 | return; | |
5403 | end if; | |
5404 | ||
0577b0b1 | 5405 | -- Check for various cases where we should suppress the range check |
5406 | ||
5407 | -- No check if range checks suppressed for type of node | |
5408 | ||
20cf157b | 5409 | if Present (Etype (N)) and then Range_Checks_Suppressed (Etype (N)) then |
0577b0b1 | 5410 | return; |
5411 | ||
5412 | -- No check if node is an entity name, and range checks are suppressed | |
5413 | -- for this entity, or for the type of this entity. | |
5414 | ||
5415 | elsif Is_Entity_Name (N) | |
5416 | and then (Range_Checks_Suppressed (Entity (N)) | |
20cf157b | 5417 | or else Range_Checks_Suppressed (Etype (Entity (N)))) |
0577b0b1 | 5418 | then |
5419 | return; | |
5420 | ||
5421 | -- No checks if index of array, and index checks are suppressed for | |
5422 | -- the array object or the type of the array. | |
5423 | ||
5424 | elsif Nkind (Parent (N)) = N_Indexed_Component then | |
5425 | declare | |
5426 | Pref : constant Node_Id := Prefix (Parent (N)); | |
5427 | begin | |
5428 | if Is_Entity_Name (Pref) | |
5429 | and then Index_Checks_Suppressed (Entity (Pref)) | |
5430 | then | |
5431 | return; | |
5432 | elsif Index_Checks_Suppressed (Etype (Pref)) then | |
5433 | return; | |
5434 | end if; | |
5435 | end; | |
5436 | end if; | |
5437 | ||
9dfe12ae | 5438 | -- Debug trace output |
ee6ba406 | 5439 | |
9dfe12ae | 5440 | if Debug_Flag_CC then |
5441 | w ("Enable_Range_Check for node ", Int (N)); | |
5442 | Write_Str (" Source location = "); | |
5443 | wl (Sloc (N)); | |
00c403ee | 5444 | pg (Union_Id (N)); |
9dfe12ae | 5445 | end if; |
5446 | ||
feff2f05 | 5447 | -- If not in optimizing mode, set flag and we are done. We are also done |
5448 | -- (and just set the flag) if the type is not a discrete type, since it | |
5449 | -- is not worth the effort to eliminate checks for other than discrete | |
5450 | -- types. In addition, we take this same path if we have stored the | |
5451 | -- maximum number of checks possible already (a very unlikely situation, | |
39a0c1d3 | 5452 | -- but we do not want to blow up). |
9dfe12ae | 5453 | |
5454 | if Optimization_Level = 0 | |
5455 | or else No (Etype (N)) | |
5456 | or else not Is_Discrete_Type (Etype (N)) | |
5457 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 5458 | then |
00c403ee | 5459 | Activate_Range_Check (N); |
9dfe12ae | 5460 | |
5461 | if Debug_Flag_CC then | |
5462 | w ("Optimization off"); | |
5463 | end if; | |
5464 | ||
ee6ba406 | 5465 | return; |
9dfe12ae | 5466 | end if; |
ee6ba406 | 5467 | |
9dfe12ae | 5468 | -- Otherwise find out the target type |
ee6ba406 | 5469 | |
9dfe12ae | 5470 | P := Parent (N); |
ee6ba406 | 5471 | |
9dfe12ae | 5472 | -- For assignment, use left side subtype |
5473 | ||
5474 | if Nkind (P) = N_Assignment_Statement | |
5475 | and then Expression (P) = N | |
5476 | then | |
5477 | Ttyp := Etype (Name (P)); | |
5478 | ||
5479 | -- For indexed component, use subscript subtype | |
5480 | ||
5481 | elsif Nkind (P) = N_Indexed_Component then | |
5482 | declare | |
5483 | Atyp : Entity_Id; | |
5484 | Indx : Node_Id; | |
5485 | Subs : Node_Id; | |
5486 | ||
5487 | begin | |
5488 | Atyp := Etype (Prefix (P)); | |
5489 | ||
5490 | if Is_Access_Type (Atyp) then | |
5491 | Atyp := Designated_Type (Atyp); | |
f07ea091 | 5492 | |
5493 | -- If the prefix is an access to an unconstrained array, | |
feff2f05 | 5494 | -- perform check unconditionally: it depends on the bounds of |
5495 | -- an object and we cannot currently recognize whether the test | |
5496 | -- may be redundant. | |
f07ea091 | 5497 | |
5498 | if not Is_Constrained (Atyp) then | |
00c403ee | 5499 | Activate_Range_Check (N); |
f07ea091 | 5500 | return; |
5501 | end if; | |
7189d17f | 5502 | |
feff2f05 | 5503 | -- Ditto if the prefix is an explicit dereference whose designated |
5504 | -- type is unconstrained. | |
7189d17f | 5505 | |
5506 | elsif Nkind (Prefix (P)) = N_Explicit_Dereference | |
5507 | and then not Is_Constrained (Atyp) | |
5508 | then | |
00c403ee | 5509 | Activate_Range_Check (N); |
7189d17f | 5510 | return; |
9dfe12ae | 5511 | end if; |
5512 | ||
5513 | Indx := First_Index (Atyp); | |
5514 | Subs := First (Expressions (P)); | |
5515 | loop | |
5516 | if Subs = N then | |
5517 | Ttyp := Etype (Indx); | |
5518 | exit; | |
5519 | end if; | |
5520 | ||
5521 | Next_Index (Indx); | |
5522 | Next (Subs); | |
5523 | end loop; | |
5524 | end; | |
5525 | ||
5526 | -- For now, ignore all other cases, they are not so interesting | |
5527 | ||
5528 | else | |
5529 | if Debug_Flag_CC then | |
5530 | w (" target type not found, flag set"); | |
5531 | end if; | |
5532 | ||
00c403ee | 5533 | Activate_Range_Check (N); |
9dfe12ae | 5534 | return; |
5535 | end if; | |
5536 | ||
5537 | -- Evaluate and check the expression | |
5538 | ||
5539 | Find_Check | |
5540 | (Expr => N, | |
5541 | Check_Type => 'R', | |
5542 | Target_Type => Ttyp, | |
5543 | Entry_OK => OK, | |
5544 | Check_Num => Chk, | |
5545 | Ent => Ent, | |
5546 | Ofs => Ofs); | |
5547 | ||
5548 | if Debug_Flag_CC then | |
5549 | w ("Called Find_Check"); | |
5550 | w ("Target_Typ = ", Int (Ttyp)); | |
5551 | w (" OK = ", OK); | |
5552 | ||
5553 | if OK then | |
5554 | w (" Check_Num = ", Chk); | |
5555 | w (" Ent = ", Int (Ent)); | |
5556 | Write_Str (" Ofs = "); | |
5557 | pid (Ofs); | |
5558 | end if; | |
5559 | end if; | |
5560 | ||
5561 | -- If check is not of form to optimize, then set flag and we are done | |
5562 | ||
5563 | if not OK then | |
5564 | if Debug_Flag_CC then | |
5565 | w (" expression not of optimizable type, flag set"); | |
5566 | end if; | |
5567 | ||
00c403ee | 5568 | Activate_Range_Check (N); |
9dfe12ae | 5569 | return; |
5570 | end if; | |
5571 | ||
5572 | -- If check is already performed, then return without setting flag | |
5573 | ||
5574 | if Chk /= 0 then | |
5575 | if Debug_Flag_CC then | |
5576 | w ("Check suppressed!"); | |
5577 | end if; | |
5578 | ||
5579 | return; | |
5580 | end if; | |
5581 | ||
5582 | -- Here we will make a new entry for the new check | |
5583 | ||
00c403ee | 5584 | Activate_Range_Check (N); |
9dfe12ae | 5585 | Num_Saved_Checks := Num_Saved_Checks + 1; |
5586 | Saved_Checks (Num_Saved_Checks) := | |
5587 | (Killed => False, | |
5588 | Entity => Ent, | |
5589 | Offset => Ofs, | |
5590 | Check_Type => 'R', | |
5591 | Target_Type => Ttyp); | |
5592 | ||
5593 | if Debug_Flag_CC then | |
5594 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
5595 | w (" Entity = ", Int (Ent)); | |
5596 | Write_Str (" Offset = "); | |
5597 | pid (Ofs); | |
5598 | w (" Check_Type = R"); | |
5599 | w (" Target_Type = ", Int (Ttyp)); | |
00c403ee | 5600 | pg (Union_Id (Ttyp)); |
9dfe12ae | 5601 | end if; |
5602 | ||
feff2f05 | 5603 | -- If we get an exception, then something went wrong, probably because of |
5604 | -- an error in the structure of the tree due to an incorrect program. Or | |
5605 | -- it may be a bug in the optimization circuit. In either case the safest | |
5606 | -- thing is simply to set the check flag unconditionally. | |
9dfe12ae | 5607 | |
5608 | exception | |
5609 | when others => | |
00c403ee | 5610 | Activate_Range_Check (N); |
9dfe12ae | 5611 | |
5612 | if Debug_Flag_CC then | |
5613 | w (" exception occurred, range flag set"); | |
5614 | end if; | |
5615 | ||
5616 | return; | |
5617 | end Enable_Range_Check; | |
5618 | ||
5619 | ------------------ | |
5620 | -- Ensure_Valid -- | |
5621 | ------------------ | |
5622 | ||
5623 | procedure Ensure_Valid (Expr : Node_Id; Holes_OK : Boolean := False) is | |
5624 | Typ : constant Entity_Id := Etype (Expr); | |
5625 | ||
5626 | begin | |
5627 | -- Ignore call if we are not doing any validity checking | |
5628 | ||
5629 | if not Validity_Checks_On then | |
5630 | return; | |
5631 | ||
0577b0b1 | 5632 | -- Ignore call if range or validity checks suppressed on entity or type |
9dfe12ae | 5633 | |
0577b0b1 | 5634 | elsif Range_Or_Validity_Checks_Suppressed (Expr) then |
9dfe12ae | 5635 | return; |
5636 | ||
feff2f05 | 5637 | -- No check required if expression is from the expander, we assume the |
5638 | -- expander will generate whatever checks are needed. Note that this is | |
39a0c1d3 | 5639 | -- not just an optimization, it avoids infinite recursions. |
9dfe12ae | 5640 | |
5641 | -- Unchecked conversions must be checked, unless they are initialized | |
5642 | -- scalar values, as in a component assignment in an init proc. | |
5643 | ||
5644 | -- In addition, we force a check if Force_Validity_Checks is set | |
5645 | ||
5646 | elsif not Comes_From_Source (Expr) | |
5647 | and then not Force_Validity_Checks | |
5648 | and then (Nkind (Expr) /= N_Unchecked_Type_Conversion | |
5649 | or else Kill_Range_Check (Expr)) | |
5650 | then | |
5651 | return; | |
5652 | ||
5653 | -- No check required if expression is known to have valid value | |
5654 | ||
5655 | elsif Expr_Known_Valid (Expr) then | |
5656 | return; | |
5657 | ||
feff2f05 | 5658 | -- Ignore case of enumeration with holes where the flag is set not to |
5659 | -- worry about holes, since no special validity check is needed | |
9dfe12ae | 5660 | |
5661 | elsif Is_Enumeration_Type (Typ) | |
5662 | and then Has_Non_Standard_Rep (Typ) | |
5663 | and then Holes_OK | |
5664 | then | |
5665 | return; | |
5666 | ||
f2a06be9 | 5667 | -- No check required on the left-hand side of an assignment |
9dfe12ae | 5668 | |
5669 | elsif Nkind (Parent (Expr)) = N_Assignment_Statement | |
5670 | and then Expr = Name (Parent (Expr)) | |
5671 | then | |
5672 | return; | |
5673 | ||
6fb3c314 | 5674 | -- No check on a universal real constant. The context will eventually |
38f5559f | 5675 | -- convert it to a machine number for some target type, or report an |
5676 | -- illegality. | |
5677 | ||
5678 | elsif Nkind (Expr) = N_Real_Literal | |
5679 | and then Etype (Expr) = Universal_Real | |
5680 | then | |
5681 | return; | |
5682 | ||
6fb3c314 | 5683 | -- If the expression denotes a component of a packed boolean array, |
0577b0b1 | 5684 | -- no possible check applies. We ignore the old ACATS chestnuts that |
5685 | -- involve Boolean range True..True. | |
5686 | ||
5687 | -- Note: validity checks are generated for expressions that yield a | |
5688 | -- scalar type, when it is possible to create a value that is outside of | |
5689 | -- the type. If this is a one-bit boolean no such value exists. This is | |
5690 | -- an optimization, and it also prevents compiler blowing up during the | |
5691 | -- elaboration of improperly expanded packed array references. | |
5692 | ||
5693 | elsif Nkind (Expr) = N_Indexed_Component | |
5694 | and then Is_Bit_Packed_Array (Etype (Prefix (Expr))) | |
5695 | and then Root_Type (Etype (Expr)) = Standard_Boolean | |
5696 | then | |
5697 | return; | |
5698 | ||
737e8460 | 5699 | -- For an expression with actions, we want to insert the validity check |
5700 | -- on the final Expression. | |
5701 | ||
5702 | elsif Nkind (Expr) = N_Expression_With_Actions then | |
5703 | Ensure_Valid (Expression (Expr)); | |
5704 | return; | |
5705 | ||
9dfe12ae | 5706 | -- An annoying special case. If this is an out parameter of a scalar |
5707 | -- type, then the value is not going to be accessed, therefore it is | |
5708 | -- inappropriate to do any validity check at the call site. | |
5709 | ||
5710 | else | |
5711 | -- Only need to worry about scalar types | |
5712 | ||
5713 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 5714 | declare |
5715 | P : Node_Id; | |
5716 | N : Node_Id; | |
5717 | E : Entity_Id; | |
5718 | F : Entity_Id; | |
5719 | A : Node_Id; | |
5720 | L : List_Id; | |
5721 | ||
5722 | begin | |
5723 | -- Find actual argument (which may be a parameter association) | |
5724 | -- and the parent of the actual argument (the call statement) | |
5725 | ||
5726 | N := Expr; | |
5727 | P := Parent (Expr); | |
5728 | ||
5729 | if Nkind (P) = N_Parameter_Association then | |
5730 | N := P; | |
5731 | P := Parent (N); | |
5732 | end if; | |
5733 | ||
feff2f05 | 5734 | -- Only need to worry if we are argument of a procedure call |
5735 | -- since functions don't have out parameters. If this is an | |
5736 | -- indirect or dispatching call, get signature from the | |
5737 | -- subprogram type. | |
ee6ba406 | 5738 | |
5739 | if Nkind (P) = N_Procedure_Call_Statement then | |
5740 | L := Parameter_Associations (P); | |
9dfe12ae | 5741 | |
5742 | if Is_Entity_Name (Name (P)) then | |
5743 | E := Entity (Name (P)); | |
5744 | else | |
5745 | pragma Assert (Nkind (Name (P)) = N_Explicit_Dereference); | |
5746 | E := Etype (Name (P)); | |
5747 | end if; | |
ee6ba406 | 5748 | |
feff2f05 | 5749 | -- Only need to worry if there are indeed actuals, and if |
5750 | -- this could be a procedure call, otherwise we cannot get a | |
5751 | -- match (either we are not an argument, or the mode of the | |
5752 | -- formal is not OUT). This test also filters out the | |
5753 | -- generic case. | |
ee6ba406 | 5754 | |
20cf157b | 5755 | if Is_Non_Empty_List (L) and then Is_Subprogram (E) then |
5756 | ||
feff2f05 | 5757 | -- This is the loop through parameters, looking for an |
5758 | -- OUT parameter for which we are the argument. | |
ee6ba406 | 5759 | |
5760 | F := First_Formal (E); | |
5761 | A := First (L); | |
ee6ba406 | 5762 | while Present (F) loop |
5763 | if Ekind (F) = E_Out_Parameter and then A = N then | |
5764 | return; | |
5765 | end if; | |
5766 | ||
5767 | Next_Formal (F); | |
5768 | Next (A); | |
5769 | end loop; | |
5770 | end if; | |
5771 | end if; | |
5772 | end; | |
5773 | end if; | |
5774 | end if; | |
5775 | ||
fa6a6949 | 5776 | -- If this is a boolean expression, only its elementary operands need |
90a07d4c | 5777 | -- checking: if they are valid, a boolean or short-circuit operation |
5778 | -- with them will be valid as well. | |
784d4230 | 5779 | |
5780 | if Base_Type (Typ) = Standard_Boolean | |
7af38999 | 5781 | and then |
fa6a6949 | 5782 | (Nkind (Expr) in N_Op or else Nkind (Expr) in N_Short_Circuit) |
784d4230 | 5783 | then |
5784 | return; | |
5785 | end if; | |
5786 | ||
0577b0b1 | 5787 | -- If we fall through, a validity check is required |
ee6ba406 | 5788 | |
5789 | Insert_Valid_Check (Expr); | |
ce7498d3 | 5790 | |
5791 | if Is_Entity_Name (Expr) | |
5792 | and then Safe_To_Capture_Value (Expr, Entity (Expr)) | |
5793 | then | |
5794 | Set_Is_Known_Valid (Entity (Expr)); | |
5795 | end if; | |
ee6ba406 | 5796 | end Ensure_Valid; |
5797 | ||
5798 | ---------------------- | |
5799 | -- Expr_Known_Valid -- | |
5800 | ---------------------- | |
5801 | ||
5802 | function Expr_Known_Valid (Expr : Node_Id) return Boolean is | |
5803 | Typ : constant Entity_Id := Etype (Expr); | |
5804 | ||
5805 | begin | |
feff2f05 | 5806 | -- Non-scalar types are always considered valid, since they never give |
5807 | -- rise to the issues of erroneous or bounded error behavior that are | |
5808 | -- the concern. In formal reference manual terms the notion of validity | |
5809 | -- only applies to scalar types. Note that even when packed arrays are | |
5810 | -- represented using modular types, they are still arrays semantically, | |
5811 | -- so they are also always valid (in particular, the unused bits can be | |
5812 | -- random rubbish without affecting the validity of the array value). | |
ee6ba406 | 5813 | |
a88a5773 | 5814 | if not Is_Scalar_Type (Typ) or else Is_Packed_Array_Impl_Type (Typ) then |
ee6ba406 | 5815 | return True; |
5816 | ||
5817 | -- If no validity checking, then everything is considered valid | |
5818 | ||
5819 | elsif not Validity_Checks_On then | |
5820 | return True; | |
5821 | ||
5822 | -- Floating-point types are considered valid unless floating-point | |
5823 | -- validity checks have been specifically turned on. | |
5824 | ||
5825 | elsif Is_Floating_Point_Type (Typ) | |
5826 | and then not Validity_Check_Floating_Point | |
5827 | then | |
5828 | return True; | |
5829 | ||
feff2f05 | 5830 | -- If the expression is the value of an object that is known to be |
5831 | -- valid, then clearly the expression value itself is valid. | |
ee6ba406 | 5832 | |
5833 | elsif Is_Entity_Name (Expr) | |
5834 | and then Is_Known_Valid (Entity (Expr)) | |
985fe5d6 | 5835 | |
5836 | -- Exclude volatile variables | |
5837 | ||
5838 | and then not Treat_As_Volatile (Entity (Expr)) | |
ee6ba406 | 5839 | then |
5840 | return True; | |
5841 | ||
0577b0b1 | 5842 | -- References to discriminants are always considered valid. The value |
5843 | -- of a discriminant gets checked when the object is built. Within the | |
5844 | -- record, we consider it valid, and it is important to do so, since | |
5845 | -- otherwise we can try to generate bogus validity checks which | |
feff2f05 | 5846 | -- reference discriminants out of scope. Discriminants of concurrent |
5847 | -- types are excluded for the same reason. | |
0577b0b1 | 5848 | |
5849 | elsif Is_Entity_Name (Expr) | |
feff2f05 | 5850 | and then Denotes_Discriminant (Expr, Check_Concurrent => True) |
0577b0b1 | 5851 | then |
5852 | return True; | |
5853 | ||
feff2f05 | 5854 | -- If the type is one for which all values are known valid, then we are |
5855 | -- sure that the value is valid except in the slightly odd case where | |
5856 | -- the expression is a reference to a variable whose size has been | |
5857 | -- explicitly set to a value greater than the object size. | |
ee6ba406 | 5858 | |
5859 | elsif Is_Known_Valid (Typ) then | |
5860 | if Is_Entity_Name (Expr) | |
5861 | and then Ekind (Entity (Expr)) = E_Variable | |
5862 | and then Esize (Entity (Expr)) > Esize (Typ) | |
5863 | then | |
5864 | return False; | |
5865 | else | |
5866 | return True; | |
5867 | end if; | |
5868 | ||
5869 | -- Integer and character literals always have valid values, where | |
5870 | -- appropriate these will be range checked in any case. | |
5871 | ||
20cf157b | 5872 | elsif Nkind_In (Expr, N_Integer_Literal, N_Character_Literal) then |
ee6ba406 | 5873 | return True; |
5874 | ||
91e47010 | 5875 | -- Real literals are assumed to be valid in VM targets |
5876 | ||
20cf157b | 5877 | elsif VM_Target /= No_VM and then Nkind (Expr) = N_Real_Literal then |
91e47010 | 5878 | return True; |
5879 | ||
ee6ba406 | 5880 | -- If we have a type conversion or a qualification of a known valid |
5881 | -- value, then the result will always be valid. | |
5882 | ||
20cf157b | 5883 | elsif Nkind_In (Expr, N_Type_Conversion, N_Qualified_Expression) then |
ee6ba406 | 5884 | return Expr_Known_Valid (Expression (Expr)); |
5885 | ||
1eb1395f | 5886 | -- Case of expression is a non-floating-point operator. In this case we |
5887 | -- can assume the result is valid the generated code for the operator | |
5888 | -- will include whatever checks are needed (e.g. range checks) to ensure | |
5889 | -- validity. This assumption does not hold for the floating-point case, | |
5890 | -- since floating-point operators can generate Infinite or NaN results | |
5891 | -- which are considered invalid. | |
5892 | ||
5893 | -- Historical note: in older versions, the exemption of floating-point | |
5894 | -- types from this assumption was done only in cases where the parent | |
5895 | -- was an assignment, function call or parameter association. Presumably | |
5896 | -- the idea was that in other contexts, the result would be checked | |
5897 | -- elsewhere, but this list of cases was missing tests (at least the | |
5898 | -- N_Object_Declaration case, as shown by a reported missing validity | |
5899 | -- check), and it is not clear why function calls but not procedure | |
5900 | -- calls were tested for. It really seems more accurate and much | |
5901 | -- safer to recognize that expressions which are the result of a | |
5902 | -- floating-point operator can never be assumed to be valid. | |
5903 | ||
5904 | elsif Nkind (Expr) in N_Op and then not Is_Floating_Point_Type (Typ) then | |
5905 | return True; | |
1d90d657 | 5906 | |
feff2f05 | 5907 | -- The result of a membership test is always valid, since it is true or |
5908 | -- false, there are no other possibilities. | |
0577b0b1 | 5909 | |
5910 | elsif Nkind (Expr) in N_Membership_Test then | |
5911 | return True; | |
5912 | ||
ee6ba406 | 5913 | -- For all other cases, we do not know the expression is valid |
5914 | ||
5915 | else | |
5916 | return False; | |
5917 | end if; | |
5918 | end Expr_Known_Valid; | |
5919 | ||
9dfe12ae | 5920 | ---------------- |
5921 | -- Find_Check -- | |
5922 | ---------------- | |
5923 | ||
5924 | procedure Find_Check | |
5925 | (Expr : Node_Id; | |
5926 | Check_Type : Character; | |
5927 | Target_Type : Entity_Id; | |
5928 | Entry_OK : out Boolean; | |
5929 | Check_Num : out Nat; | |
5930 | Ent : out Entity_Id; | |
5931 | Ofs : out Uint) | |
5932 | is | |
5933 | function Within_Range_Of | |
5934 | (Target_Type : Entity_Id; | |
314a23b6 | 5935 | Check_Type : Entity_Id) return Boolean; |
9dfe12ae | 5936 | -- Given a requirement for checking a range against Target_Type, and |
5937 | -- and a range Check_Type against which a check has already been made, | |
5938 | -- determines if the check against check type is sufficient to ensure | |
5939 | -- that no check against Target_Type is required. | |
5940 | ||
5941 | --------------------- | |
5942 | -- Within_Range_Of -- | |
5943 | --------------------- | |
5944 | ||
5945 | function Within_Range_Of | |
5946 | (Target_Type : Entity_Id; | |
314a23b6 | 5947 | Check_Type : Entity_Id) return Boolean |
9dfe12ae | 5948 | is |
5949 | begin | |
5950 | if Target_Type = Check_Type then | |
5951 | return True; | |
5952 | ||
5953 | else | |
5954 | declare | |
5955 | Tlo : constant Node_Id := Type_Low_Bound (Target_Type); | |
5956 | Thi : constant Node_Id := Type_High_Bound (Target_Type); | |
5957 | Clo : constant Node_Id := Type_Low_Bound (Check_Type); | |
5958 | Chi : constant Node_Id := Type_High_Bound (Check_Type); | |
5959 | ||
5960 | begin | |
5961 | if (Tlo = Clo | |
5962 | or else (Compile_Time_Known_Value (Tlo) | |
5963 | and then | |
5964 | Compile_Time_Known_Value (Clo) | |
5965 | and then | |
5966 | Expr_Value (Clo) >= Expr_Value (Tlo))) | |
5967 | and then | |
5968 | (Thi = Chi | |
5969 | or else (Compile_Time_Known_Value (Thi) | |
5970 | and then | |
5971 | Compile_Time_Known_Value (Chi) | |
5972 | and then | |
5973 | Expr_Value (Chi) <= Expr_Value (Clo))) | |
5974 | then | |
5975 | return True; | |
5976 | else | |
5977 | return False; | |
5978 | end if; | |
5979 | end; | |
5980 | end if; | |
5981 | end Within_Range_Of; | |
5982 | ||
5983 | -- Start of processing for Find_Check | |
5984 | ||
5985 | begin | |
ed195555 | 5986 | -- Establish default, in case no entry is found |
9dfe12ae | 5987 | |
5988 | Check_Num := 0; | |
5989 | ||
5990 | -- Case of expression is simple entity reference | |
5991 | ||
5992 | if Is_Entity_Name (Expr) then | |
5993 | Ent := Entity (Expr); | |
5994 | Ofs := Uint_0; | |
5995 | ||
5996 | -- Case of expression is entity + known constant | |
5997 | ||
5998 | elsif Nkind (Expr) = N_Op_Add | |
5999 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
6000 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
6001 | then | |
6002 | Ent := Entity (Left_Opnd (Expr)); | |
6003 | Ofs := Expr_Value (Right_Opnd (Expr)); | |
6004 | ||
6005 | -- Case of expression is entity - known constant | |
6006 | ||
6007 | elsif Nkind (Expr) = N_Op_Subtract | |
6008 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
6009 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
6010 | then | |
6011 | Ent := Entity (Left_Opnd (Expr)); | |
6012 | Ofs := UI_Negate (Expr_Value (Right_Opnd (Expr))); | |
6013 | ||
6014 | -- Any other expression is not of the right form | |
6015 | ||
6016 | else | |
6017 | Ent := Empty; | |
6018 | Ofs := Uint_0; | |
6019 | Entry_OK := False; | |
6020 | return; | |
6021 | end if; | |
6022 | ||
feff2f05 | 6023 | -- Come here with expression of appropriate form, check if entity is an |
6024 | -- appropriate one for our purposes. | |
9dfe12ae | 6025 | |
6026 | if (Ekind (Ent) = E_Variable | |
cc60bd16 | 6027 | or else Is_Constant_Object (Ent)) |
9dfe12ae | 6028 | and then not Is_Library_Level_Entity (Ent) |
6029 | then | |
6030 | Entry_OK := True; | |
6031 | else | |
6032 | Entry_OK := False; | |
6033 | return; | |
6034 | end if; | |
6035 | ||
6036 | -- See if there is matching check already | |
6037 | ||
6038 | for J in reverse 1 .. Num_Saved_Checks loop | |
6039 | declare | |
6040 | SC : Saved_Check renames Saved_Checks (J); | |
9dfe12ae | 6041 | begin |
6042 | if SC.Killed = False | |
6043 | and then SC.Entity = Ent | |
6044 | and then SC.Offset = Ofs | |
6045 | and then SC.Check_Type = Check_Type | |
6046 | and then Within_Range_Of (Target_Type, SC.Target_Type) | |
6047 | then | |
6048 | Check_Num := J; | |
6049 | return; | |
6050 | end if; | |
6051 | end; | |
6052 | end loop; | |
6053 | ||
6054 | -- If we fall through entry was not found | |
6055 | ||
9dfe12ae | 6056 | return; |
6057 | end Find_Check; | |
6058 | ||
6059 | --------------------------------- | |
6060 | -- Generate_Discriminant_Check -- | |
6061 | --------------------------------- | |
6062 | ||
6063 | -- Note: the code for this procedure is derived from the | |
feff2f05 | 6064 | -- Emit_Discriminant_Check Routine in trans.c. |
9dfe12ae | 6065 | |
6066 | procedure Generate_Discriminant_Check (N : Node_Id) is | |
6067 | Loc : constant Source_Ptr := Sloc (N); | |
6068 | Pref : constant Node_Id := Prefix (N); | |
6069 | Sel : constant Node_Id := Selector_Name (N); | |
6070 | ||
6071 | Orig_Comp : constant Entity_Id := | |
b6341c67 | 6072 | Original_Record_Component (Entity (Sel)); |
9dfe12ae | 6073 | -- The original component to be checked |
6074 | ||
6075 | Discr_Fct : constant Entity_Id := | |
b6341c67 | 6076 | Discriminant_Checking_Func (Orig_Comp); |
9dfe12ae | 6077 | -- The discriminant checking function |
6078 | ||
6079 | Discr : Entity_Id; | |
6080 | -- One discriminant to be checked in the type | |
6081 | ||
6082 | Real_Discr : Entity_Id; | |
6083 | -- Actual discriminant in the call | |
6084 | ||
6085 | Pref_Type : Entity_Id; | |
6086 | -- Type of relevant prefix (ignoring private/access stuff) | |
6087 | ||
6088 | Args : List_Id; | |
6089 | -- List of arguments for function call | |
6090 | ||
6091 | Formal : Entity_Id; | |
feff2f05 | 6092 | -- Keep track of the formal corresponding to the actual we build for |
6093 | -- each discriminant, in order to be able to perform the necessary type | |
6094 | -- conversions. | |
9dfe12ae | 6095 | |
6096 | Scomp : Node_Id; | |
6097 | -- Selected component reference for checking function argument | |
6098 | ||
6099 | begin | |
6100 | Pref_Type := Etype (Pref); | |
6101 | ||
6102 | -- Force evaluation of the prefix, so that it does not get evaluated | |
6103 | -- twice (once for the check, once for the actual reference). Such a | |
20cf157b | 6104 | -- double evaluation is always a potential source of inefficiency, and |
6105 | -- is functionally incorrect in the volatile case, or when the prefix | |
6106 | -- may have side-effects. A non-volatile entity or a component of a | |
6107 | -- non-volatile entity requires no evaluation. | |
9dfe12ae | 6108 | |
6109 | if Is_Entity_Name (Pref) then | |
6110 | if Treat_As_Volatile (Entity (Pref)) then | |
6111 | Force_Evaluation (Pref, Name_Req => True); | |
6112 | end if; | |
6113 | ||
6114 | elsif Treat_As_Volatile (Etype (Pref)) then | |
20cf157b | 6115 | Force_Evaluation (Pref, Name_Req => True); |
9dfe12ae | 6116 | |
6117 | elsif Nkind (Pref) = N_Selected_Component | |
6118 | and then Is_Entity_Name (Prefix (Pref)) | |
6119 | then | |
6120 | null; | |
6121 | ||
6122 | else | |
6123 | Force_Evaluation (Pref, Name_Req => True); | |
6124 | end if; | |
6125 | ||
6126 | -- For a tagged type, use the scope of the original component to | |
6127 | -- obtain the type, because ??? | |
6128 | ||
6129 | if Is_Tagged_Type (Scope (Orig_Comp)) then | |
6130 | Pref_Type := Scope (Orig_Comp); | |
6131 | ||
feff2f05 | 6132 | -- For an untagged derived type, use the discriminants of the parent |
6133 | -- which have been renamed in the derivation, possibly by a one-to-many | |
d1a2e31b | 6134 | -- discriminant constraint. For untagged type, initially get the Etype |
feff2f05 | 6135 | -- of the prefix |
9dfe12ae | 6136 | |
6137 | else | |
6138 | if Is_Derived_Type (Pref_Type) | |
6139 | and then Number_Discriminants (Pref_Type) /= | |
6140 | Number_Discriminants (Etype (Base_Type (Pref_Type))) | |
6141 | then | |
6142 | Pref_Type := Etype (Base_Type (Pref_Type)); | |
6143 | end if; | |
6144 | end if; | |
6145 | ||
6146 | -- We definitely should have a checking function, This routine should | |
6147 | -- not be called if no discriminant checking function is present. | |
6148 | ||
6149 | pragma Assert (Present (Discr_Fct)); | |
6150 | ||
6151 | -- Create the list of the actual parameters for the call. This list | |
6152 | -- is the list of the discriminant fields of the record expression to | |
6153 | -- be discriminant checked. | |
6154 | ||
6155 | Args := New_List; | |
6156 | Formal := First_Formal (Discr_Fct); | |
6157 | Discr := First_Discriminant (Pref_Type); | |
6158 | while Present (Discr) loop | |
6159 | ||
6160 | -- If we have a corresponding discriminant field, and a parent | |
6161 | -- subtype is present, then we want to use the corresponding | |
6162 | -- discriminant since this is the one with the useful value. | |
6163 | ||
6164 | if Present (Corresponding_Discriminant (Discr)) | |
6165 | and then Ekind (Pref_Type) = E_Record_Type | |
6166 | and then Present (Parent_Subtype (Pref_Type)) | |
6167 | then | |
6168 | Real_Discr := Corresponding_Discriminant (Discr); | |
6169 | else | |
6170 | Real_Discr := Discr; | |
6171 | end if; | |
6172 | ||
6173 | -- Construct the reference to the discriminant | |
6174 | ||
6175 | Scomp := | |
6176 | Make_Selected_Component (Loc, | |
6177 | Prefix => | |
6178 | Unchecked_Convert_To (Pref_Type, | |
6179 | Duplicate_Subexpr (Pref)), | |
6180 | Selector_Name => New_Occurrence_Of (Real_Discr, Loc)); | |
6181 | ||
6182 | -- Manually analyze and resolve this selected component. We really | |
6183 | -- want it just as it appears above, and do not want the expander | |
feff2f05 | 6184 | -- playing discriminal games etc with this reference. Then we append |
6185 | -- the argument to the list we are gathering. | |
9dfe12ae | 6186 | |
6187 | Set_Etype (Scomp, Etype (Real_Discr)); | |
6188 | Set_Analyzed (Scomp, True); | |
6189 | Append_To (Args, Convert_To (Etype (Formal), Scomp)); | |
6190 | ||
6191 | Next_Formal_With_Extras (Formal); | |
6192 | Next_Discriminant (Discr); | |
6193 | end loop; | |
6194 | ||
6195 | -- Now build and insert the call | |
6196 | ||
6197 | Insert_Action (N, | |
6198 | Make_Raise_Constraint_Error (Loc, | |
6199 | Condition => | |
6200 | Make_Function_Call (Loc, | |
20cf157b | 6201 | Name => New_Occurrence_Of (Discr_Fct, Loc), |
9dfe12ae | 6202 | Parameter_Associations => Args), |
6203 | Reason => CE_Discriminant_Check_Failed)); | |
6204 | end Generate_Discriminant_Check; | |
6205 | ||
5c99c290 | 6206 | --------------------------- |
6207 | -- Generate_Index_Checks -- | |
6208 | --------------------------- | |
9dfe12ae | 6209 | |
6210 | procedure Generate_Index_Checks (N : Node_Id) is | |
05f3e139 | 6211 | |
6212 | function Entity_Of_Prefix return Entity_Id; | |
6213 | -- Returns the entity of the prefix of N (or Empty if not found) | |
6214 | ||
3f42e2a7 | 6215 | ---------------------- |
6216 | -- Entity_Of_Prefix -- | |
6217 | ---------------------- | |
6218 | ||
05f3e139 | 6219 | function Entity_Of_Prefix return Entity_Id is |
e5d38095 | 6220 | P : Node_Id; |
6221 | ||
05f3e139 | 6222 | begin |
e5d38095 | 6223 | P := Prefix (N); |
05f3e139 | 6224 | while not Is_Entity_Name (P) loop |
6225 | if not Nkind_In (P, N_Selected_Component, | |
6226 | N_Indexed_Component) | |
6227 | then | |
6228 | return Empty; | |
6229 | end if; | |
6230 | ||
6231 | P := Prefix (P); | |
6232 | end loop; | |
6233 | ||
6234 | return Entity (P); | |
6235 | end Entity_Of_Prefix; | |
6236 | ||
6237 | -- Local variables | |
6238 | ||
6239 | Loc : constant Source_Ptr := Sloc (N); | |
6240 | A : constant Node_Id := Prefix (N); | |
6241 | A_Ent : constant Entity_Id := Entity_Of_Prefix; | |
6242 | Sub : Node_Id; | |
9dfe12ae | 6243 | |
3f42e2a7 | 6244 | -- Start of processing for Generate_Index_Checks |
6245 | ||
9dfe12ae | 6246 | begin |
05f3e139 | 6247 | -- Ignore call if the prefix is not an array since we have a serious |
6248 | -- error in the sources. Ignore it also if index checks are suppressed | |
6249 | -- for array object or type. | |
0577b0b1 | 6250 | |
05f3e139 | 6251 | if not Is_Array_Type (Etype (A)) |
20cf157b | 6252 | or else (Present (A_Ent) and then Index_Checks_Suppressed (A_Ent)) |
0577b0b1 | 6253 | or else Index_Checks_Suppressed (Etype (A)) |
6254 | then | |
6255 | return; | |
df9fba45 | 6256 | |
6257 | -- The indexed component we are dealing with contains 'Loop_Entry in its | |
6258 | -- prefix. This case arises when analysis has determined that constructs | |
6259 | -- such as | |
6260 | ||
6261 | -- Prefix'Loop_Entry (Expr) | |
6262 | -- Prefix'Loop_Entry (Expr1, Expr2, ... ExprN) | |
6263 | ||
6264 | -- require rewriting for error detection purposes. A side effect of this | |
6265 | -- action is the generation of index checks that mention 'Loop_Entry. | |
6266 | -- Delay the generation of the check until 'Loop_Entry has been properly | |
6267 | -- expanded. This is done in Expand_Loop_Entry_Attributes. | |
6268 | ||
6269 | elsif Nkind (Prefix (N)) = N_Attribute_Reference | |
6270 | and then Attribute_Name (Prefix (N)) = Name_Loop_Entry | |
6271 | then | |
6272 | return; | |
0577b0b1 | 6273 | end if; |
6274 | ||
05f3e139 | 6275 | -- Generate a raise of constraint error with the appropriate reason and |
6276 | -- a condition of the form: | |
6277 | ||
3f42e2a7 | 6278 | -- Base_Type (Sub) not in Array'Range (Subscript) |
05f3e139 | 6279 | |
6280 | -- Note that the reason we generate the conversion to the base type here | |
6281 | -- is that we definitely want the range check to take place, even if it | |
6282 | -- looks like the subtype is OK. Optimization considerations that allow | |
6283 | -- us to omit the check have already been taken into account in the | |
6284 | -- setting of the Do_Range_Check flag earlier on. | |
0577b0b1 | 6285 | |
9dfe12ae | 6286 | Sub := First (Expressions (N)); |
05f3e139 | 6287 | |
6288 | -- Handle string literals | |
6289 | ||
6290 | if Ekind (Etype (A)) = E_String_Literal_Subtype then | |
9dfe12ae | 6291 | if Do_Range_Check (Sub) then |
6292 | Set_Do_Range_Check (Sub, False); | |
6293 | ||
05f3e139 | 6294 | -- For string literals we obtain the bounds of the string from the |
6295 | -- associated subtype. | |
9dfe12ae | 6296 | |
05f3e139 | 6297 | Insert_Action (N, |
094ed68e | 6298 | Make_Raise_Constraint_Error (Loc, |
6299 | Condition => | |
6300 | Make_Not_In (Loc, | |
6301 | Left_Opnd => | |
6302 | Convert_To (Base_Type (Etype (Sub)), | |
6303 | Duplicate_Subexpr_Move_Checks (Sub)), | |
6304 | Right_Opnd => | |
6305 | Make_Attribute_Reference (Loc, | |
83c6c069 | 6306 | Prefix => New_Occurrence_Of (Etype (A), Loc), |
094ed68e | 6307 | Attribute_Name => Name_Range)), |
6308 | Reason => CE_Index_Check_Failed)); | |
05f3e139 | 6309 | end if; |
9dfe12ae | 6310 | |
05f3e139 | 6311 | -- General case |
9dfe12ae | 6312 | |
05f3e139 | 6313 | else |
6314 | declare | |
6315 | A_Idx : Node_Id := Empty; | |
6316 | A_Range : Node_Id; | |
6317 | Ind : Nat; | |
6318 | Num : List_Id; | |
6319 | Range_N : Node_Id; | |
9dfe12ae | 6320 | |
05f3e139 | 6321 | begin |
6322 | A_Idx := First_Index (Etype (A)); | |
6323 | Ind := 1; | |
6324 | while Present (Sub) loop | |
6325 | if Do_Range_Check (Sub) then | |
6326 | Set_Do_Range_Check (Sub, False); | |
9dfe12ae | 6327 | |
05f3e139 | 6328 | -- Force evaluation except for the case of a simple name of |
6329 | -- a non-volatile entity. | |
9dfe12ae | 6330 | |
05f3e139 | 6331 | if not Is_Entity_Name (Sub) |
6332 | or else Treat_As_Volatile (Entity (Sub)) | |
6333 | then | |
6334 | Force_Evaluation (Sub); | |
6335 | end if; | |
9dfe12ae | 6336 | |
05f3e139 | 6337 | if Nkind (A_Idx) = N_Range then |
6338 | A_Range := A_Idx; | |
6339 | ||
6340 | elsif Nkind (A_Idx) = N_Identifier | |
6341 | or else Nkind (A_Idx) = N_Expanded_Name | |
6342 | then | |
6343 | A_Range := Scalar_Range (Entity (A_Idx)); | |
6344 | ||
6345 | else pragma Assert (Nkind (A_Idx) = N_Subtype_Indication); | |
6346 | A_Range := Range_Expression (Constraint (A_Idx)); | |
6347 | end if; | |
6348 | ||
6349 | -- For array objects with constant bounds we can generate | |
6350 | -- the index check using the bounds of the type of the index | |
6351 | ||
6352 | if Present (A_Ent) | |
6353 | and then Ekind (A_Ent) = E_Variable | |
6354 | and then Is_Constant_Bound (Low_Bound (A_Range)) | |
6355 | and then Is_Constant_Bound (High_Bound (A_Range)) | |
6356 | then | |
6357 | Range_N := | |
6358 | Make_Attribute_Reference (Loc, | |
3f42e2a7 | 6359 | Prefix => |
83c6c069 | 6360 | New_Occurrence_Of (Etype (A_Idx), Loc), |
05f3e139 | 6361 | Attribute_Name => Name_Range); |
6362 | ||
6363 | -- For arrays with non-constant bounds we cannot generate | |
6364 | -- the index check using the bounds of the type of the index | |
6365 | -- since it may reference discriminants of some enclosing | |
6366 | -- type. We obtain the bounds directly from the prefix | |
6367 | -- object. | |
6368 | ||
6369 | else | |
6370 | if Ind = 1 then | |
6371 | Num := No_List; | |
6372 | else | |
6373 | Num := New_List (Make_Integer_Literal (Loc, Ind)); | |
6374 | end if; | |
6375 | ||
6376 | Range_N := | |
6377 | Make_Attribute_Reference (Loc, | |
6378 | Prefix => | |
6379 | Duplicate_Subexpr_Move_Checks (A, Name_Req => True), | |
6380 | Attribute_Name => Name_Range, | |
6381 | Expressions => Num); | |
6382 | end if; | |
6383 | ||
6384 | Insert_Action (N, | |
094ed68e | 6385 | Make_Raise_Constraint_Error (Loc, |
6386 | Condition => | |
6387 | Make_Not_In (Loc, | |
6388 | Left_Opnd => | |
6389 | Convert_To (Base_Type (Etype (Sub)), | |
6390 | Duplicate_Subexpr_Move_Checks (Sub)), | |
6391 | Right_Opnd => Range_N), | |
6392 | Reason => CE_Index_Check_Failed)); | |
05f3e139 | 6393 | end if; |
6394 | ||
6395 | A_Idx := Next_Index (A_Idx); | |
6396 | Ind := Ind + 1; | |
6397 | Next (Sub); | |
6398 | end loop; | |
6399 | end; | |
6400 | end if; | |
9dfe12ae | 6401 | end Generate_Index_Checks; |
6402 | ||
6403 | -------------------------- | |
6404 | -- Generate_Range_Check -- | |
6405 | -------------------------- | |
6406 | ||
6407 | procedure Generate_Range_Check | |
6408 | (N : Node_Id; | |
6409 | Target_Type : Entity_Id; | |
6410 | Reason : RT_Exception_Code) | |
6411 | is | |
6412 | Loc : constant Source_Ptr := Sloc (N); | |
6413 | Source_Type : constant Entity_Id := Etype (N); | |
6414 | Source_Base_Type : constant Entity_Id := Base_Type (Source_Type); | |
6415 | Target_Base_Type : constant Entity_Id := Base_Type (Target_Type); | |
6416 | ||
1f5d83cf | 6417 | procedure Convert_And_Check_Range; |
6418 | -- Convert the conversion operand to the target base type and save in | |
6419 | -- a temporary. Then check the converted value against the range of the | |
6420 | -- target subtype. | |
6421 | ||
124f1911 | 6422 | ----------------------------- |
6423 | -- Convert_And_Check_Range -- | |
6424 | ----------------------------- | |
1f5d83cf | 6425 | |
124f1911 | 6426 | procedure Convert_And_Check_Range is |
1f5d83cf | 6427 | Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
6428 | ||
124f1911 | 6429 | begin |
6430 | -- We make a temporary to hold the value of the converted value | |
6431 | -- (converted to the base type), and then do the test against this | |
6432 | -- temporary. The conversion itself is replaced by an occurrence of | |
6433 | -- Tnn and followed by the explicit range check. Note that checks | |
6434 | -- are suppressed for this code, since we don't want a recursive | |
1f5d83cf | 6435 | -- range check popping up. |
6436 | ||
124f1911 | 6437 | -- Tnn : constant Target_Base_Type := Target_Base_Type (N); |
6438 | -- [constraint_error when Tnn not in Target_Type] | |
6439 | ||
1f5d83cf | 6440 | Insert_Actions (N, New_List ( |
6441 | Make_Object_Declaration (Loc, | |
6442 | Defining_Identifier => Tnn, | |
6443 | Object_Definition => New_Occurrence_Of (Target_Base_Type, Loc), | |
6444 | Constant_Present => True, | |
6445 | Expression => | |
6446 | Make_Type_Conversion (Loc, | |
6447 | Subtype_Mark => New_Occurrence_Of (Target_Base_Type, Loc), | |
6448 | Expression => Duplicate_Subexpr (N))), | |
6449 | ||
6450 | Make_Raise_Constraint_Error (Loc, | |
6451 | Condition => | |
6452 | Make_Not_In (Loc, | |
6453 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
6454 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
6455 | Reason => Reason)), | |
6456 | Suppress => All_Checks); | |
6457 | ||
6458 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
6459 | ||
6460 | -- Set the type of N, because the declaration for Tnn might not | |
6461 | -- be analyzed yet, as is the case if N appears within a record | |
6462 | -- declaration, as a discriminant constraint or expression. | |
6463 | ||
6464 | Set_Etype (N, Target_Base_Type); | |
6465 | end Convert_And_Check_Range; | |
6466 | ||
6467 | -- Start of processing for Generate_Range_Check | |
6468 | ||
9dfe12ae | 6469 | begin |
feff2f05 | 6470 | -- First special case, if the source type is already within the range |
6471 | -- of the target type, then no check is needed (probably we should have | |
6472 | -- stopped Do_Range_Check from being set in the first place, but better | |
cda40848 | 6473 | -- late than never in preventing junk code and junk flag settings. |
9dfe12ae | 6474 | |
7a1dabb3 | 6475 | if In_Subrange_Of (Source_Type, Target_Type) |
b40670e1 | 6476 | |
6477 | -- We do NOT apply this if the source node is a literal, since in this | |
6478 | -- case the literal has already been labeled as having the subtype of | |
6479 | -- the target. | |
6480 | ||
9dfe12ae | 6481 | and then not |
b40670e1 | 6482 | (Nkind_In (N, N_Integer_Literal, N_Real_Literal, N_Character_Literal) |
9dfe12ae | 6483 | or else |
b40670e1 | 6484 | (Is_Entity_Name (N) |
6485 | and then Ekind (Entity (N)) = E_Enumeration_Literal)) | |
9dfe12ae | 6486 | then |
cda40848 | 6487 | Set_Do_Range_Check (N, False); |
9dfe12ae | 6488 | return; |
6489 | end if; | |
6490 | ||
cda40848 | 6491 | -- Here a check is needed. If the expander is not active, or if we are |
6492 | -- in GNATProve mode, then simply set the Do_Range_Check flag and we | |
6493 | -- are done. In both these cases, we just want to see the range check | |
6494 | -- flag set, we do not want to generate the explicit range check code. | |
6495 | ||
6496 | if GNATprove_Mode or else not Expander_Active then | |
6497 | Set_Do_Range_Check (N, True); | |
6498 | return; | |
6499 | end if; | |
6500 | ||
6501 | -- Here we will generate an explicit range check, so we don't want to | |
6502 | -- set the Do_Range check flag, since the range check is taken care of | |
6503 | -- by the code we will generate. | |
6504 | ||
6505 | Set_Do_Range_Check (N, False); | |
6506 | ||
6507 | -- Force evaluation of the node, so that it does not get evaluated twice | |
6508 | -- (once for the check, once for the actual reference). Such a double | |
6509 | -- evaluation is always a potential source of inefficiency, and is | |
6510 | -- functionally incorrect in the volatile case. | |
9dfe12ae | 6511 | |
b40670e1 | 6512 | if not Is_Entity_Name (N) or else Treat_As_Volatile (Entity (N)) then |
9dfe12ae | 6513 | Force_Evaluation (N); |
6514 | end if; | |
6515 | ||
feff2f05 | 6516 | -- The easiest case is when Source_Base_Type and Target_Base_Type are |
6517 | -- the same since in this case we can simply do a direct check of the | |
6518 | -- value of N against the bounds of Target_Type. | |
9dfe12ae | 6519 | |
6520 | -- [constraint_error when N not in Target_Type] | |
6521 | ||
6522 | -- Note: this is by far the most common case, for example all cases of | |
6523 | -- checks on the RHS of assignments are in this category, but not all | |
6524 | -- cases are like this. Notably conversions can involve two types. | |
6525 | ||
6526 | if Source_Base_Type = Target_Base_Type then | |
99ed4b4c | 6527 | |
6528 | -- Insert the explicit range check. Note that we suppress checks for | |
6529 | -- this code, since we don't want a recursive range check popping up. | |
6530 | ||
9dfe12ae | 6531 | Insert_Action (N, |
6532 | Make_Raise_Constraint_Error (Loc, | |
6533 | Condition => | |
6534 | Make_Not_In (Loc, | |
6535 | Left_Opnd => Duplicate_Subexpr (N), | |
6536 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
99ed4b4c | 6537 | Reason => Reason), |
6538 | Suppress => All_Checks); | |
9dfe12ae | 6539 | |
6540 | -- Next test for the case where the target type is within the bounds | |
6541 | -- of the base type of the source type, since in this case we can | |
6542 | -- simply convert these bounds to the base type of T to do the test. | |
6543 | ||
6544 | -- [constraint_error when N not in | |
6545 | -- Source_Base_Type (Target_Type'First) | |
6546 | -- .. | |
6547 | -- Source_Base_Type(Target_Type'Last))] | |
6548 | ||
f2a06be9 | 6549 | -- The conversions will always work and need no check |
9dfe12ae | 6550 | |
a9b57347 | 6551 | -- Unchecked_Convert_To is used instead of Convert_To to handle the case |
6552 | -- of converting from an enumeration value to an integer type, such as | |
6553 | -- occurs for the case of generating a range check on Enum'Val(Exp) | |
6554 | -- (which used to be handled by gigi). This is OK, since the conversion | |
6555 | -- itself does not require a check. | |
6556 | ||
7a1dabb3 | 6557 | elsif In_Subrange_Of (Target_Type, Source_Base_Type) then |
99ed4b4c | 6558 | |
6559 | -- Insert the explicit range check. Note that we suppress checks for | |
6560 | -- this code, since we don't want a recursive range check popping up. | |
6561 | ||
1f5d83cf | 6562 | if Is_Discrete_Type (Source_Base_Type) |
6563 | and then | |
6564 | Is_Discrete_Type (Target_Base_Type) | |
6565 | then | |
6566 | Insert_Action (N, | |
6567 | Make_Raise_Constraint_Error (Loc, | |
6568 | Condition => | |
6569 | Make_Not_In (Loc, | |
6570 | Left_Opnd => Duplicate_Subexpr (N), | |
6571 | ||
6572 | Right_Opnd => | |
6573 | Make_Range (Loc, | |
6574 | Low_Bound => | |
6575 | Unchecked_Convert_To (Source_Base_Type, | |
6576 | Make_Attribute_Reference (Loc, | |
6577 | Prefix => | |
6578 | New_Occurrence_Of (Target_Type, Loc), | |
6579 | Attribute_Name => Name_First)), | |
6580 | ||
6581 | High_Bound => | |
6582 | Unchecked_Convert_To (Source_Base_Type, | |
6583 | Make_Attribute_Reference (Loc, | |
6584 | Prefix => | |
6585 | New_Occurrence_Of (Target_Type, Loc), | |
6586 | Attribute_Name => Name_Last)))), | |
6587 | Reason => Reason), | |
6588 | Suppress => All_Checks); | |
9dfe12ae | 6589 | |
1f5d83cf | 6590 | -- For conversions involving at least one type that is not discrete, |
6591 | -- first convert to target type and then generate the range check. | |
6592 | -- This avoids problems with values that are close to a bound of the | |
6593 | -- target type that would fail a range check when done in a larger | |
6594 | -- source type before converting but would pass if converted with | |
6595 | -- rounding and then checked (such as in float-to-float conversions). | |
6596 | ||
6597 | else | |
6598 | Convert_And_Check_Range; | |
6599 | end if; | |
9dfe12ae | 6600 | |
feff2f05 | 6601 | -- Note that at this stage we now that the Target_Base_Type is not in |
6602 | -- the range of the Source_Base_Type (since even the Target_Type itself | |
6603 | -- is not in this range). It could still be the case that Source_Type is | |
6604 | -- in range of the target base type since we have not checked that case. | |
9dfe12ae | 6605 | |
feff2f05 | 6606 | -- If that is the case, we can freely convert the source to the target, |
6607 | -- and then test the target result against the bounds. | |
9dfe12ae | 6608 | |
7a1dabb3 | 6609 | elsif In_Subrange_Of (Source_Type, Target_Base_Type) then |
1f5d83cf | 6610 | Convert_And_Check_Range; |
9dfe12ae | 6611 | |
6612 | -- At this stage, we know that we have two scalar types, which are | |
6613 | -- directly convertible, and where neither scalar type has a base | |
6614 | -- range that is in the range of the other scalar type. | |
6615 | ||
6616 | -- The only way this can happen is with a signed and unsigned type. | |
6617 | -- So test for these two cases: | |
6618 | ||
6619 | else | |
6620 | -- Case of the source is unsigned and the target is signed | |
6621 | ||
6622 | if Is_Unsigned_Type (Source_Base_Type) | |
6623 | and then not Is_Unsigned_Type (Target_Base_Type) | |
6624 | then | |
6625 | -- If the source is unsigned and the target is signed, then we | |
6626 | -- know that the source is not shorter than the target (otherwise | |
6627 | -- the source base type would be in the target base type range). | |
6628 | ||
feff2f05 | 6629 | -- In other words, the unsigned type is either the same size as |
6630 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 6631 | |
6632 | pragma Assert | |
6633 | (Esize (Source_Base_Type) >= Esize (Target_Base_Type)); | |
6634 | ||
6635 | -- We only need to check the low bound if the low bound of the | |
6636 | -- target type is non-negative. If the low bound of the target | |
6637 | -- type is negative, then we know that we will fit fine. | |
6638 | ||
6639 | -- If the high bound of the target type is negative, then we | |
6640 | -- know we have a constraint error, since we can't possibly | |
6641 | -- have a negative source. | |
6642 | ||
6643 | -- With these two checks out of the way, we can do the check | |
6644 | -- using the source type safely | |
6645 | ||
39a0c1d3 | 6646 | -- This is definitely the most annoying case. |
9dfe12ae | 6647 | |
6648 | -- [constraint_error | |
6649 | -- when (Target_Type'First >= 0 | |
6650 | -- and then | |
6651 | -- N < Source_Base_Type (Target_Type'First)) | |
6652 | -- or else Target_Type'Last < 0 | |
6653 | -- or else N > Source_Base_Type (Target_Type'Last)]; | |
6654 | ||
6655 | -- We turn off all checks since we know that the conversions | |
6656 | -- will work fine, given the guards for negative values. | |
6657 | ||
6658 | Insert_Action (N, | |
6659 | Make_Raise_Constraint_Error (Loc, | |
6660 | Condition => | |
6661 | Make_Or_Else (Loc, | |
6662 | Make_Or_Else (Loc, | |
6663 | Left_Opnd => | |
6664 | Make_And_Then (Loc, | |
6665 | Left_Opnd => Make_Op_Ge (Loc, | |
6666 | Left_Opnd => | |
6667 | Make_Attribute_Reference (Loc, | |
6668 | Prefix => | |
6669 | New_Occurrence_Of (Target_Type, Loc), | |
6670 | Attribute_Name => Name_First), | |
6671 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
6672 | ||
6673 | Right_Opnd => | |
6674 | Make_Op_Lt (Loc, | |
6675 | Left_Opnd => Duplicate_Subexpr (N), | |
6676 | Right_Opnd => | |
6677 | Convert_To (Source_Base_Type, | |
6678 | Make_Attribute_Reference (Loc, | |
6679 | Prefix => | |
6680 | New_Occurrence_Of (Target_Type, Loc), | |
6681 | Attribute_Name => Name_First)))), | |
6682 | ||
6683 | Right_Opnd => | |
6684 | Make_Op_Lt (Loc, | |
6685 | Left_Opnd => | |
6686 | Make_Attribute_Reference (Loc, | |
6687 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
6688 | Attribute_Name => Name_Last), | |
6689 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0))), | |
6690 | ||
6691 | Right_Opnd => | |
6692 | Make_Op_Gt (Loc, | |
6693 | Left_Opnd => Duplicate_Subexpr (N), | |
6694 | Right_Opnd => | |
6695 | Convert_To (Source_Base_Type, | |
6696 | Make_Attribute_Reference (Loc, | |
6697 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
6698 | Attribute_Name => Name_Last)))), | |
6699 | ||
6700 | Reason => Reason), | |
6701 | Suppress => All_Checks); | |
6702 | ||
6703 | -- Only remaining possibility is that the source is signed and | |
fc75802a | 6704 | -- the target is unsigned. |
9dfe12ae | 6705 | |
6706 | else | |
6707 | pragma Assert (not Is_Unsigned_Type (Source_Base_Type) | |
20cf157b | 6708 | and then Is_Unsigned_Type (Target_Base_Type)); |
9dfe12ae | 6709 | |
feff2f05 | 6710 | -- If the source is signed and the target is unsigned, then we |
6711 | -- know that the target is not shorter than the source (otherwise | |
6712 | -- the target base type would be in the source base type range). | |
9dfe12ae | 6713 | |
feff2f05 | 6714 | -- In other words, the unsigned type is either the same size as |
6715 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 6716 | |
feff2f05 | 6717 | -- Clearly we have an error if the source value is negative since |
6718 | -- no unsigned type can have negative values. If the source type | |
6719 | -- is non-negative, then the check can be done using the target | |
6720 | -- type. | |
9dfe12ae | 6721 | |
6722 | -- Tnn : constant Target_Base_Type (N) := Target_Type; | |
6723 | ||
6724 | -- [constraint_error | |
6725 | -- when N < 0 or else Tnn not in Target_Type]; | |
6726 | ||
feff2f05 | 6727 | -- We turn off all checks for the conversion of N to the target |
6728 | -- base type, since we generate the explicit check to ensure that | |
6729 | -- the value is non-negative | |
9dfe12ae | 6730 | |
6731 | declare | |
46eb6933 | 6732 | Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
9dfe12ae | 6733 | |
6734 | begin | |
6735 | Insert_Actions (N, New_List ( | |
6736 | Make_Object_Declaration (Loc, | |
6737 | Defining_Identifier => Tnn, | |
6738 | Object_Definition => | |
6739 | New_Occurrence_Of (Target_Base_Type, Loc), | |
6740 | Constant_Present => True, | |
6741 | Expression => | |
a9b57347 | 6742 | Make_Unchecked_Type_Conversion (Loc, |
9dfe12ae | 6743 | Subtype_Mark => |
6744 | New_Occurrence_Of (Target_Base_Type, Loc), | |
6745 | Expression => Duplicate_Subexpr (N))), | |
6746 | ||
6747 | Make_Raise_Constraint_Error (Loc, | |
6748 | Condition => | |
6749 | Make_Or_Else (Loc, | |
6750 | Left_Opnd => | |
6751 | Make_Op_Lt (Loc, | |
6752 | Left_Opnd => Duplicate_Subexpr (N), | |
6753 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
6754 | ||
6755 | Right_Opnd => | |
6756 | Make_Not_In (Loc, | |
6757 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
6758 | Right_Opnd => | |
6759 | New_Occurrence_Of (Target_Type, Loc))), | |
6760 | ||
20cf157b | 6761 | Reason => Reason)), |
9dfe12ae | 6762 | Suppress => All_Checks); |
6763 | ||
feff2f05 | 6764 | -- Set the Etype explicitly, because Insert_Actions may have |
6765 | -- placed the declaration in the freeze list for an enclosing | |
6766 | -- construct, and thus it is not analyzed yet. | |
9dfe12ae | 6767 | |
6768 | Set_Etype (Tnn, Target_Base_Type); | |
6769 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
6770 | end; | |
6771 | end if; | |
6772 | end if; | |
6773 | end Generate_Range_Check; | |
6774 | ||
2af58f67 | 6775 | ------------------ |
6776 | -- Get_Check_Id -- | |
6777 | ------------------ | |
6778 | ||
6779 | function Get_Check_Id (N : Name_Id) return Check_Id is | |
6780 | begin | |
6781 | -- For standard check name, we can do a direct computation | |
6782 | ||
6783 | if N in First_Check_Name .. Last_Check_Name then | |
6784 | return Check_Id (N - (First_Check_Name - 1)); | |
6785 | ||
6786 | -- For non-standard names added by pragma Check_Name, search table | |
6787 | ||
6788 | else | |
6789 | for J in All_Checks + 1 .. Check_Names.Last loop | |
6790 | if Check_Names.Table (J) = N then | |
6791 | return J; | |
6792 | end if; | |
6793 | end loop; | |
6794 | end if; | |
6795 | ||
6796 | -- No matching name found | |
6797 | ||
6798 | return No_Check_Id; | |
6799 | end Get_Check_Id; | |
6800 | ||
ee6ba406 | 6801 | --------------------- |
6802 | -- Get_Discriminal -- | |
6803 | --------------------- | |
6804 | ||
6805 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is | |
6806 | Loc : constant Source_Ptr := Sloc (E); | |
6807 | D : Entity_Id; | |
6808 | Sc : Entity_Id; | |
6809 | ||
6810 | begin | |
0577b0b1 | 6811 | -- The bound can be a bona fide parameter of a protected operation, |
6812 | -- rather than a prival encoded as an in-parameter. | |
6813 | ||
6814 | if No (Discriminal_Link (Entity (Bound))) then | |
6815 | return Bound; | |
6816 | end if; | |
6817 | ||
2af58f67 | 6818 | -- Climb the scope stack looking for an enclosing protected type. If |
6819 | -- we run out of scopes, return the bound itself. | |
6820 | ||
6821 | Sc := Scope (E); | |
6822 | while Present (Sc) loop | |
6823 | if Sc = Standard_Standard then | |
6824 | return Bound; | |
2af58f67 | 6825 | elsif Ekind (Sc) = E_Protected_Type then |
6826 | exit; | |
6827 | end if; | |
6828 | ||
6829 | Sc := Scope (Sc); | |
6830 | end loop; | |
6831 | ||
ee6ba406 | 6832 | D := First_Discriminant (Sc); |
2af58f67 | 6833 | while Present (D) loop |
6834 | if Chars (D) = Chars (Bound) then | |
6835 | return New_Occurrence_Of (Discriminal (D), Loc); | |
6836 | end if; | |
ee6ba406 | 6837 | |
ee6ba406 | 6838 | Next_Discriminant (D); |
6839 | end loop; | |
6840 | ||
2af58f67 | 6841 | return Bound; |
ee6ba406 | 6842 | end Get_Discriminal; |
6843 | ||
2af58f67 | 6844 | ---------------------- |
6845 | -- Get_Range_Checks -- | |
6846 | ---------------------- | |
6847 | ||
6848 | function Get_Range_Checks | |
6849 | (Ck_Node : Node_Id; | |
6850 | Target_Typ : Entity_Id; | |
6851 | Source_Typ : Entity_Id := Empty; | |
6852 | Warn_Node : Node_Id := Empty) return Check_Result | |
6853 | is | |
6854 | begin | |
20cf157b | 6855 | return |
6856 | Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Warn_Node); | |
2af58f67 | 6857 | end Get_Range_Checks; |
6858 | ||
ee6ba406 | 6859 | ------------------ |
6860 | -- Guard_Access -- | |
6861 | ------------------ | |
6862 | ||
6863 | function Guard_Access | |
6864 | (Cond : Node_Id; | |
6865 | Loc : Source_Ptr; | |
314a23b6 | 6866 | Ck_Node : Node_Id) return Node_Id |
ee6ba406 | 6867 | is |
6868 | begin | |
6869 | if Nkind (Cond) = N_Or_Else then | |
6870 | Set_Paren_Count (Cond, 1); | |
6871 | end if; | |
6872 | ||
6873 | if Nkind (Ck_Node) = N_Allocator then | |
6874 | return Cond; | |
20cf157b | 6875 | |
ee6ba406 | 6876 | else |
6877 | return | |
6878 | Make_And_Then (Loc, | |
6879 | Left_Opnd => | |
6880 | Make_Op_Ne (Loc, | |
9dfe12ae | 6881 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), |
ee6ba406 | 6882 | Right_Opnd => Make_Null (Loc)), |
6883 | Right_Opnd => Cond); | |
6884 | end if; | |
6885 | end Guard_Access; | |
6886 | ||
6887 | ----------------------------- | |
6888 | -- Index_Checks_Suppressed -- | |
6889 | ----------------------------- | |
6890 | ||
6891 | function Index_Checks_Suppressed (E : Entity_Id) return Boolean is | |
6892 | begin | |
9dfe12ae | 6893 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
6894 | return Is_Check_Suppressed (E, Index_Check); | |
6895 | else | |
fafc6b97 | 6896 | return Scope_Suppress.Suppress (Index_Check); |
9dfe12ae | 6897 | end if; |
ee6ba406 | 6898 | end Index_Checks_Suppressed; |
6899 | ||
6900 | ---------------- | |
6901 | -- Initialize -- | |
6902 | ---------------- | |
6903 | ||
6904 | procedure Initialize is | |
6905 | begin | |
6906 | for J in Determine_Range_Cache_N'Range loop | |
6907 | Determine_Range_Cache_N (J) := Empty; | |
6908 | end loop; | |
2af58f67 | 6909 | |
6910 | Check_Names.Init; | |
6911 | ||
6912 | for J in Int range 1 .. All_Checks loop | |
6913 | Check_Names.Append (Name_Id (Int (First_Check_Name) + J - 1)); | |
6914 | end loop; | |
ee6ba406 | 6915 | end Initialize; |
6916 | ||
6917 | ------------------------- | |
6918 | -- Insert_Range_Checks -- | |
6919 | ------------------------- | |
6920 | ||
6921 | procedure Insert_Range_Checks | |
6922 | (Checks : Check_Result; | |
6923 | Node : Node_Id; | |
6924 | Suppress_Typ : Entity_Id; | |
6925 | Static_Sloc : Source_Ptr := No_Location; | |
6926 | Flag_Node : Node_Id := Empty; | |
6927 | Do_Before : Boolean := False) | |
6928 | is | |
6929 | Internal_Flag_Node : Node_Id := Flag_Node; | |
6930 | Internal_Static_Sloc : Source_Ptr := Static_Sloc; | |
6931 | ||
6932 | Check_Node : Node_Id; | |
6933 | Checks_On : constant Boolean := | |
b6341c67 | 6934 | (not Index_Checks_Suppressed (Suppress_Typ)) |
6935 | or else (not Range_Checks_Suppressed (Suppress_Typ)); | |
ee6ba406 | 6936 | |
6937 | begin | |
feff2f05 | 6938 | -- For now we just return if Checks_On is false, however this should be |
6939 | -- enhanced to check for an always True value in the condition and to | |
6940 | -- generate a compilation warning??? | |
ee6ba406 | 6941 | |
ac9184ed | 6942 | if not Expander_Active or not Checks_On then |
ee6ba406 | 6943 | return; |
6944 | end if; | |
6945 | ||
6946 | if Static_Sloc = No_Location then | |
6947 | Internal_Static_Sloc := Sloc (Node); | |
6948 | end if; | |
6949 | ||
6950 | if No (Flag_Node) then | |
6951 | Internal_Flag_Node := Node; | |
6952 | end if; | |
6953 | ||
6954 | for J in 1 .. 2 loop | |
6955 | exit when No (Checks (J)); | |
6956 | ||
6957 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
6958 | and then Present (Condition (Checks (J))) | |
6959 | then | |
6960 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
6961 | Check_Node := Checks (J); | |
6962 | Mark_Rewrite_Insertion (Check_Node); | |
6963 | ||
6964 | if Do_Before then | |
6965 | Insert_Before_And_Analyze (Node, Check_Node); | |
6966 | else | |
6967 | Insert_After_And_Analyze (Node, Check_Node); | |
6968 | end if; | |
6969 | ||
6970 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
6971 | end if; | |
6972 | ||
6973 | else | |
6974 | Check_Node := | |
f15731c4 | 6975 | Make_Raise_Constraint_Error (Internal_Static_Sloc, |
6976 | Reason => CE_Range_Check_Failed); | |
ee6ba406 | 6977 | Mark_Rewrite_Insertion (Check_Node); |
6978 | ||
6979 | if Do_Before then | |
6980 | Insert_Before_And_Analyze (Node, Check_Node); | |
6981 | else | |
6982 | Insert_After_And_Analyze (Node, Check_Node); | |
6983 | end if; | |
6984 | end if; | |
6985 | end loop; | |
6986 | end Insert_Range_Checks; | |
6987 | ||
6988 | ------------------------ | |
6989 | -- Insert_Valid_Check -- | |
6990 | ------------------------ | |
6991 | ||
6992 | procedure Insert_Valid_Check (Expr : Node_Id) is | |
6993 | Loc : constant Source_Ptr := Sloc (Expr); | |
70580828 | 6994 | Typ : constant Entity_Id := Etype (Expr); |
8b718dab | 6995 | Exp : Node_Id; |
ee6ba406 | 6996 | |
6997 | begin | |
06ad5813 | 6998 | -- Do not insert if checks off, or if not checking validity or |
6999 | -- if expression is known to be valid | |
ee6ba406 | 7000 | |
0577b0b1 | 7001 | if not Validity_Checks_On |
7002 | or else Range_Or_Validity_Checks_Suppressed (Expr) | |
06ad5813 | 7003 | or else Expr_Known_Valid (Expr) |
ee6ba406 | 7004 | then |
8b718dab | 7005 | return; |
7006 | end if; | |
ee6ba406 | 7007 | |
42c57d55 | 7008 | -- Do not insert checks within a predicate function. This will arise |
7009 | -- if the current unit and the predicate function are being compiled | |
7010 | -- with validity checks enabled. | |
70580828 | 7011 | |
7012 | if Present (Predicate_Function (Typ)) | |
7013 | and then Current_Scope = Predicate_Function (Typ) | |
7014 | then | |
7015 | return; | |
7016 | end if; | |
7017 | ||
310c1cde | 7018 | -- If the expression is a packed component of a modular type of the |
7019 | -- right size, the data is always valid. | |
7020 | ||
7021 | if Nkind (Expr) = N_Selected_Component | |
7022 | and then Present (Component_Clause (Entity (Selector_Name (Expr)))) | |
7023 | and then Is_Modular_Integer_Type (Typ) | |
7024 | and then Modulus (Typ) = 2 ** Esize (Entity (Selector_Name (Expr))) | |
7025 | then | |
7026 | return; | |
7027 | end if; | |
7028 | ||
8b718dab | 7029 | -- If we have a checked conversion, then validity check applies to |
7030 | -- the expression inside the conversion, not the result, since if | |
7031 | -- the expression inside is valid, then so is the conversion result. | |
ee6ba406 | 7032 | |
8b718dab | 7033 | Exp := Expr; |
7034 | while Nkind (Exp) = N_Type_Conversion loop | |
7035 | Exp := Expression (Exp); | |
7036 | end loop; | |
7037 | ||
0577b0b1 | 7038 | -- We are about to insert the validity check for Exp. We save and |
7039 | -- reset the Do_Range_Check flag over this validity check, and then | |
7040 | -- put it back for the final original reference (Exp may be rewritten). | |
7041 | ||
7042 | declare | |
7043 | DRC : constant Boolean := Do_Range_Check (Exp); | |
23abd64d | 7044 | PV : Node_Id; |
7045 | CE : Node_Id; | |
05fcfafb | 7046 | |
0577b0b1 | 7047 | begin |
7048 | Set_Do_Range_Check (Exp, False); | |
7049 | ||
06ad5813 | 7050 | -- Force evaluation to avoid multiple reads for atomic/volatile |
7051 | ||
fa771c05 | 7052 | -- Note: we set Name_Req to False. We used to set it to True, with |
7053 | -- the thinking that a name is required as the prefix of the 'Valid | |
7054 | -- call, but in fact the check that the prefix of an attribute is | |
7055 | -- a name is in the parser, and we just don't require it here. | |
7056 | -- Moreover, when we set Name_Req to True, that interfered with the | |
7057 | -- checking for Volatile, since we couldn't just capture the value. | |
7058 | ||
06ad5813 | 7059 | if Is_Entity_Name (Exp) |
7060 | and then Is_Volatile (Entity (Exp)) | |
7061 | then | |
fa771c05 | 7062 | -- Same reasoning as above for setting Name_Req to False |
7063 | ||
7064 | Force_Evaluation (Exp, Name_Req => False); | |
06ad5813 | 7065 | end if; |
7066 | ||
23abd64d | 7067 | -- Build the prefix for the 'Valid call |
7068 | ||
fa771c05 | 7069 | PV := Duplicate_Subexpr_No_Checks (Exp, Name_Req => False); |
0577b0b1 | 7070 | |
443bdccb | 7071 | -- A rather specialized test. If PV is an analyzed expression which |
7072 | -- is an indexed component of a packed array that has not been | |
7073 | -- properly expanded, turn off its Analyzed flag to make sure it | |
5f46de53 | 7074 | -- gets properly reexpanded. If the prefix is an access value, |
7075 | -- the dereference will be added later. | |
23abd64d | 7076 | |
7077 | -- The reason this arises is that Duplicate_Subexpr_No_Checks did | |
7078 | -- an analyze with the old parent pointer. This may point e.g. to | |
7079 | -- a subprogram call, which deactivates this expansion. | |
7080 | ||
7081 | if Analyzed (PV) | |
7082 | and then Nkind (PV) = N_Indexed_Component | |
5f46de53 | 7083 | and then Is_Array_Type (Etype (Prefix (PV))) |
a88a5773 | 7084 | and then Present (Packed_Array_Impl_Type (Etype (Prefix (PV)))) |
23abd64d | 7085 | then |
7086 | Set_Analyzed (PV, False); | |
7087 | end if; | |
7088 | ||
fa771c05 | 7089 | -- Build the raise CE node to check for validity. We build a type |
7090 | -- qualification for the prefix, since it may not be of the form of | |
7091 | -- a name, and we don't care in this context! | |
23abd64d | 7092 | |
7093 | CE := | |
0577b0b1 | 7094 | Make_Raise_Constraint_Error (Loc, |
7095 | Condition => | |
7096 | Make_Op_Not (Loc, | |
7097 | Right_Opnd => | |
7098 | Make_Attribute_Reference (Loc, | |
23abd64d | 7099 | Prefix => PV, |
0577b0b1 | 7100 | Attribute_Name => Name_Valid)), |
23abd64d | 7101 | Reason => CE_Invalid_Data); |
7102 | ||
7103 | -- Insert the validity check. Note that we do this with validity | |
7104 | -- checks turned off, to avoid recursion, we do not want validity | |
39a0c1d3 | 7105 | -- checks on the validity checking code itself. |
23abd64d | 7106 | |
7107 | Insert_Action (Expr, CE, Suppress => Validity_Check); | |
0577b0b1 | 7108 | |
6fb3c314 | 7109 | -- If the expression is a reference to an element of a bit-packed |
0577b0b1 | 7110 | -- array, then it is rewritten as a renaming declaration. If the |
7111 | -- expression is an actual in a call, it has not been expanded, | |
7112 | -- waiting for the proper point at which to do it. The same happens | |
7113 | -- with renamings, so that we have to force the expansion now. This | |
7114 | -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb | |
7115 | -- and exp_ch6.adb. | |
7116 | ||
7117 | if Is_Entity_Name (Exp) | |
7118 | and then Nkind (Parent (Entity (Exp))) = | |
20cf157b | 7119 | N_Object_Renaming_Declaration |
0577b0b1 | 7120 | then |
7121 | declare | |
7122 | Old_Exp : constant Node_Id := Name (Parent (Entity (Exp))); | |
7123 | begin | |
7124 | if Nkind (Old_Exp) = N_Indexed_Component | |
7125 | and then Is_Bit_Packed_Array (Etype (Prefix (Old_Exp))) | |
7126 | then | |
7127 | Expand_Packed_Element_Reference (Old_Exp); | |
7128 | end if; | |
7129 | end; | |
7130 | end if; | |
7131 | ||
7132 | -- Put back the Do_Range_Check flag on the resulting (possibly | |
7133 | -- rewritten) expression. | |
7134 | ||
7135 | -- Note: it might be thought that a validity check is not required | |
7136 | -- when a range check is present, but that's not the case, because | |
7137 | -- the back end is allowed to assume for the range check that the | |
7138 | -- operand is within its declared range (an assumption that validity | |
39a0c1d3 | 7139 | -- checking is all about NOT assuming). |
0577b0b1 | 7140 | |
00c403ee | 7141 | -- Note: no need to worry about Possible_Local_Raise here, it will |
7142 | -- already have been called if original node has Do_Range_Check set. | |
7143 | ||
0577b0b1 | 7144 | Set_Do_Range_Check (Exp, DRC); |
7145 | end; | |
ee6ba406 | 7146 | end Insert_Valid_Check; |
7147 | ||
3cce7f32 | 7148 | ------------------------------------- |
7149 | -- Is_Signed_Integer_Arithmetic_Op -- | |
7150 | ------------------------------------- | |
7151 | ||
7152 | function Is_Signed_Integer_Arithmetic_Op (N : Node_Id) return Boolean is | |
7153 | begin | |
7154 | case Nkind (N) is | |
7155 | when N_Op_Abs | N_Op_Add | N_Op_Divide | N_Op_Expon | | |
7156 | N_Op_Minus | N_Op_Mod | N_Op_Multiply | N_Op_Plus | | |
7157 | N_Op_Rem | N_Op_Subtract => | |
7158 | return Is_Signed_Integer_Type (Etype (N)); | |
7159 | ||
92f1631f | 7160 | when N_If_Expression | N_Case_Expression => |
0326b4d4 | 7161 | return Is_Signed_Integer_Type (Etype (N)); |
7162 | ||
3cce7f32 | 7163 | when others => |
7164 | return False; | |
7165 | end case; | |
7166 | end Is_Signed_Integer_Arithmetic_Op; | |
7167 | ||
fa7497e8 | 7168 | ---------------------------------- |
7169 | -- Install_Null_Excluding_Check -- | |
7170 | ---------------------------------- | |
7171 | ||
7172 | procedure Install_Null_Excluding_Check (N : Node_Id) is | |
9f294c82 | 7173 | Loc : constant Source_Ptr := Sloc (Parent (N)); |
84d0d4a5 | 7174 | Typ : constant Entity_Id := Etype (N); |
7175 | ||
7b31b357 | 7176 | function Safe_To_Capture_In_Parameter_Value return Boolean; |
7177 | -- Determines if it is safe to capture Known_Non_Null status for an | |
7178 | -- the entity referenced by node N. The caller ensures that N is indeed | |
7179 | -- an entity name. It is safe to capture the non-null status for an IN | |
7180 | -- parameter when the reference occurs within a declaration that is sure | |
7181 | -- to be executed as part of the declarative region. | |
7870823d | 7182 | |
84d0d4a5 | 7183 | procedure Mark_Non_Null; |
7870823d | 7184 | -- After installation of check, if the node in question is an entity |
7185 | -- name, then mark this entity as non-null if possible. | |
7186 | ||
7b31b357 | 7187 | function Safe_To_Capture_In_Parameter_Value return Boolean is |
7870823d | 7188 | E : constant Entity_Id := Entity (N); |
7189 | S : constant Entity_Id := Current_Scope; | |
7190 | S_Par : Node_Id; | |
7191 | ||
7192 | begin | |
7b31b357 | 7193 | if Ekind (E) /= E_In_Parameter then |
7194 | return False; | |
7195 | end if; | |
7870823d | 7196 | |
7197 | -- Two initial context checks. We must be inside a subprogram body | |
7198 | -- with declarations and reference must not appear in nested scopes. | |
7199 | ||
7b31b357 | 7200 | if (Ekind (S) /= E_Function and then Ekind (S) /= E_Procedure) |
7870823d | 7201 | or else Scope (E) /= S |
7202 | then | |
7203 | return False; | |
7204 | end if; | |
7205 | ||
7206 | S_Par := Parent (Parent (S)); | |
7207 | ||
7208 | if Nkind (S_Par) /= N_Subprogram_Body | |
7209 | or else No (Declarations (S_Par)) | |
7210 | then | |
7211 | return False; | |
7212 | end if; | |
7213 | ||
7214 | declare | |
7215 | N_Decl : Node_Id; | |
7216 | P : Node_Id; | |
7217 | ||
7218 | begin | |
7219 | -- Retrieve the declaration node of N (if any). Note that N | |
7220 | -- may be a part of a complex initialization expression. | |
7221 | ||
7222 | P := Parent (N); | |
7223 | N_Decl := Empty; | |
7224 | while Present (P) loop | |
7225 | ||
7b31b357 | 7226 | -- If we have a short circuit form, and we are within the right |
7227 | -- hand expression, we return false, since the right hand side | |
7228 | -- is not guaranteed to be elaborated. | |
7229 | ||
7230 | if Nkind (P) in N_Short_Circuit | |
7231 | and then N = Right_Opnd (P) | |
7232 | then | |
7233 | return False; | |
7234 | end if; | |
7235 | ||
92f1631f | 7236 | -- Similarly, if we are in an if expression and not part of the |
7237 | -- condition, then we return False, since neither the THEN or | |
7238 | -- ELSE dependent expressions will always be elaborated. | |
7b31b357 | 7239 | |
92f1631f | 7240 | if Nkind (P) = N_If_Expression |
7b31b357 | 7241 | and then N /= First (Expressions (P)) |
7242 | then | |
7243 | return False; | |
e977c0cf | 7244 | end if; |
7245 | ||
20cf157b | 7246 | -- If within a case expression, and not part of the expression, |
7247 | -- then return False, since a particular dependent expression | |
7248 | -- may not always be elaborated | |
e977c0cf | 7249 | |
7250 | if Nkind (P) = N_Case_Expression | |
7251 | and then N /= Expression (P) | |
7252 | then | |
7253 | return False; | |
7b31b357 | 7254 | end if; |
7255 | ||
20cf157b | 7256 | -- While traversing the parent chain, if node N belongs to a |
7257 | -- statement, then it may never appear in a declarative region. | |
7870823d | 7258 | |
7259 | if Nkind (P) in N_Statement_Other_Than_Procedure_Call | |
7260 | or else Nkind (P) = N_Procedure_Call_Statement | |
7261 | then | |
7262 | return False; | |
7263 | end if; | |
7264 | ||
7b31b357 | 7265 | -- If we are at a declaration, record it and exit |
7266 | ||
7870823d | 7267 | if Nkind (P) in N_Declaration |
7268 | and then Nkind (P) not in N_Subprogram_Specification | |
7269 | then | |
7270 | N_Decl := P; | |
7271 | exit; | |
7272 | end if; | |
7273 | ||
7274 | P := Parent (P); | |
7275 | end loop; | |
7276 | ||
7277 | if No (N_Decl) then | |
7278 | return False; | |
7279 | end if; | |
7280 | ||
7281 | return List_Containing (N_Decl) = Declarations (S_Par); | |
7282 | end; | |
7b31b357 | 7283 | end Safe_To_Capture_In_Parameter_Value; |
84d0d4a5 | 7284 | |
7285 | ------------------- | |
7286 | -- Mark_Non_Null -- | |
7287 | ------------------- | |
7288 | ||
7289 | procedure Mark_Non_Null is | |
7290 | begin | |
7870823d | 7291 | -- Only case of interest is if node N is an entity name |
7292 | ||
84d0d4a5 | 7293 | if Is_Entity_Name (N) then |
7870823d | 7294 | |
7295 | -- For sure, we want to clear an indication that this is known to | |
39a0c1d3 | 7296 | -- be null, since if we get past this check, it definitely is not. |
7870823d | 7297 | |
84d0d4a5 | 7298 | Set_Is_Known_Null (Entity (N), False); |
7299 | ||
7870823d | 7300 | -- We can mark the entity as known to be non-null if either it is |
7301 | -- safe to capture the value, or in the case of an IN parameter, | |
7302 | -- which is a constant, if the check we just installed is in the | |
7303 | -- declarative region of the subprogram body. In this latter case, | |
7b31b357 | 7304 | -- a check is decisive for the rest of the body if the expression |
7305 | -- is sure to be elaborated, since we know we have to elaborate | |
7306 | -- all declarations before executing the body. | |
7307 | ||
7308 | -- Couldn't this always be part of Safe_To_Capture_Value ??? | |
7870823d | 7309 | |
7310 | if Safe_To_Capture_Value (N, Entity (N)) | |
7b31b357 | 7311 | or else Safe_To_Capture_In_Parameter_Value |
7870823d | 7312 | then |
7313 | Set_Is_Known_Non_Null (Entity (N)); | |
84d0d4a5 | 7314 | end if; |
7315 | end if; | |
7316 | end Mark_Non_Null; | |
7317 | ||
7318 | -- Start of processing for Install_Null_Excluding_Check | |
fa7497e8 | 7319 | |
7320 | begin | |
84d0d4a5 | 7321 | pragma Assert (Is_Access_Type (Typ)); |
fa7497e8 | 7322 | |
46e32b5e | 7323 | -- No check inside a generic, check will be emitted in instance |
fa7497e8 | 7324 | |
84d0d4a5 | 7325 | if Inside_A_Generic then |
fa7497e8 | 7326 | return; |
84d0d4a5 | 7327 | end if; |
7328 | ||
7329 | -- No check needed if known to be non-null | |
7330 | ||
7331 | if Known_Non_Null (N) then | |
05fcfafb | 7332 | return; |
84d0d4a5 | 7333 | end if; |
fa7497e8 | 7334 | |
84d0d4a5 | 7335 | -- If known to be null, here is where we generate a compile time check |
7336 | ||
7337 | if Known_Null (N) then | |
d16989f1 | 7338 | |
20cf157b | 7339 | -- Avoid generating warning message inside init procs. In SPARK mode |
7340 | -- we can go ahead and call Apply_Compile_Time_Constraint_Error | |
46e32b5e | 7341 | -- since it will be turned into an error in any case. |
d16989f1 | 7342 | |
46e32b5e | 7343 | if (not Inside_Init_Proc or else SPARK_Mode = On) |
7344 | ||
28d5d68f | 7345 | -- Do not emit the warning within a conditional expression, |
7346 | -- where the expression might not be evaluated, and the warning | |
7347 | -- appear as extraneous noise. | |
46e32b5e | 7348 | |
7349 | and then not Within_Case_Or_If_Expression (N) | |
7350 | then | |
d16989f1 | 7351 | Apply_Compile_Time_Constraint_Error |
4098232e | 7352 | (N, "null value not allowed here??", CE_Access_Check_Failed); |
46e32b5e | 7353 | |
7354 | -- Remaining cases, where we silently insert the raise | |
7355 | ||
d16989f1 | 7356 | else |
7357 | Insert_Action (N, | |
7358 | Make_Raise_Constraint_Error (Loc, | |
7359 | Reason => CE_Access_Check_Failed)); | |
7360 | end if; | |
7361 | ||
84d0d4a5 | 7362 | Mark_Non_Null; |
7363 | return; | |
7364 | end if; | |
7365 | ||
7366 | -- If entity is never assigned, for sure a warning is appropriate | |
7367 | ||
7368 | if Is_Entity_Name (N) then | |
7369 | Check_Unset_Reference (N); | |
fa7497e8 | 7370 | end if; |
84d0d4a5 | 7371 | |
7372 | -- No check needed if checks are suppressed on the range. Note that we | |
7373 | -- don't set Is_Known_Non_Null in this case (we could legitimately do | |
7374 | -- so, since the program is erroneous, but we don't like to casually | |
7375 | -- propagate such conclusions from erroneosity). | |
7376 | ||
7377 | if Access_Checks_Suppressed (Typ) then | |
7378 | return; | |
7379 | end if; | |
7380 | ||
2af58f67 | 7381 | -- No check needed for access to concurrent record types generated by |
7382 | -- the expander. This is not just an optimization (though it does indeed | |
7383 | -- remove junk checks). It also avoids generation of junk warnings. | |
7384 | ||
7385 | if Nkind (N) in N_Has_Chars | |
7386 | and then Chars (N) = Name_uObject | |
7387 | and then Is_Concurrent_Record_Type | |
7388 | (Directly_Designated_Type (Etype (N))) | |
7389 | then | |
7390 | return; | |
7391 | end if; | |
7392 | ||
228836e8 | 7393 | -- No check needed in interface thunks since the runtime check is |
7394 | -- already performed at the caller side. | |
7395 | ||
7396 | if Is_Thunk (Current_Scope) then | |
7397 | return; | |
7398 | end if; | |
7399 | ||
472ea160 | 7400 | -- No check needed for the Get_Current_Excep.all.all idiom generated by |
7401 | -- the expander within exception handlers, since we know that the value | |
7402 | -- can never be null. | |
7403 | ||
7404 | -- Is this really the right way to do this? Normally we generate such | |
7405 | -- code in the expander with checks off, and that's how we suppress this | |
7406 | -- kind of junk check ??? | |
7407 | ||
7408 | if Nkind (N) = N_Function_Call | |
7409 | and then Nkind (Name (N)) = N_Explicit_Dereference | |
7410 | and then Nkind (Prefix (Name (N))) = N_Identifier | |
7411 | and then Is_RTE (Entity (Prefix (Name (N))), RE_Get_Current_Excep) | |
7412 | then | |
7413 | return; | |
7414 | end if; | |
7415 | ||
84d0d4a5 | 7416 | -- Otherwise install access check |
7417 | ||
7418 | Insert_Action (N, | |
7419 | Make_Raise_Constraint_Error (Loc, | |
7420 | Condition => | |
7421 | Make_Op_Eq (Loc, | |
7422 | Left_Opnd => Duplicate_Subexpr_Move_Checks (N), | |
7423 | Right_Opnd => Make_Null (Loc)), | |
7424 | Reason => CE_Access_Check_Failed)); | |
7425 | ||
7426 | Mark_Non_Null; | |
fa7497e8 | 7427 | end Install_Null_Excluding_Check; |
7428 | ||
ee6ba406 | 7429 | -------------------------- |
7430 | -- Install_Static_Check -- | |
7431 | -------------------------- | |
7432 | ||
7433 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is | |
cda40848 | 7434 | Stat : constant Boolean := Is_OK_Static_Expression (R_Cno); |
ee6ba406 | 7435 | Typ : constant Entity_Id := Etype (R_Cno); |
7436 | ||
7437 | begin | |
f15731c4 | 7438 | Rewrite (R_Cno, |
7439 | Make_Raise_Constraint_Error (Loc, | |
7440 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 7441 | Set_Analyzed (R_Cno); |
7442 | Set_Etype (R_Cno, Typ); | |
7443 | Set_Raises_Constraint_Error (R_Cno); | |
7444 | Set_Is_Static_Expression (R_Cno, Stat); | |
840ab274 | 7445 | |
7446 | -- Now deal with possible local raise handling | |
7447 | ||
7448 | Possible_Local_Raise (R_Cno, Standard_Constraint_Error); | |
ee6ba406 | 7449 | end Install_Static_Check; |
7450 | ||
3cce7f32 | 7451 | ------------------------- |
7452 | -- Is_Check_Suppressed -- | |
7453 | ------------------------- | |
7454 | ||
7455 | function Is_Check_Suppressed (E : Entity_Id; C : Check_Id) return Boolean is | |
7456 | Ptr : Suppress_Stack_Entry_Ptr; | |
7457 | ||
7458 | begin | |
7459 | -- First search the local entity suppress stack. We search this from the | |
7460 | -- top of the stack down so that we get the innermost entry that applies | |
7461 | -- to this case if there are nested entries. | |
7462 | ||
7463 | Ptr := Local_Suppress_Stack_Top; | |
7464 | while Ptr /= null loop | |
7465 | if (Ptr.Entity = Empty or else Ptr.Entity = E) | |
7466 | and then (Ptr.Check = All_Checks or else Ptr.Check = C) | |
7467 | then | |
7468 | return Ptr.Suppress; | |
7469 | end if; | |
7470 | ||
7471 | Ptr := Ptr.Prev; | |
7472 | end loop; | |
7473 | ||
7474 | -- Now search the global entity suppress table for a matching entry. | |
7475 | -- We also search this from the top down so that if there are multiple | |
7476 | -- pragmas for the same entity, the last one applies (not clear what | |
7477 | -- or whether the RM specifies this handling, but it seems reasonable). | |
7478 | ||
7479 | Ptr := Global_Suppress_Stack_Top; | |
7480 | while Ptr /= null loop | |
7481 | if (Ptr.Entity = Empty or else Ptr.Entity = E) | |
7482 | and then (Ptr.Check = All_Checks or else Ptr.Check = C) | |
7483 | then | |
7484 | return Ptr.Suppress; | |
7485 | end if; | |
7486 | ||
7487 | Ptr := Ptr.Prev; | |
7488 | end loop; | |
7489 | ||
7490 | -- If we did not find a matching entry, then use the normal scope | |
7491 | -- suppress value after all (actually this will be the global setting | |
7492 | -- since it clearly was not overridden at any point). For a predefined | |
7493 | -- check, we test the specific flag. For a user defined check, we check | |
7494 | -- the All_Checks flag. The Overflow flag requires special handling to | |
7495 | -- deal with the General vs Assertion case | |
7496 | ||
7497 | if C = Overflow_Check then | |
7498 | return Overflow_Checks_Suppressed (Empty); | |
7499 | elsif C in Predefined_Check_Id then | |
7500 | return Scope_Suppress.Suppress (C); | |
7501 | else | |
7502 | return Scope_Suppress.Suppress (All_Checks); | |
7503 | end if; | |
7504 | end Is_Check_Suppressed; | |
7505 | ||
9dfe12ae | 7506 | --------------------- |
7507 | -- Kill_All_Checks -- | |
7508 | --------------------- | |
7509 | ||
7510 | procedure Kill_All_Checks is | |
7511 | begin | |
7512 | if Debug_Flag_CC then | |
7513 | w ("Kill_All_Checks"); | |
7514 | end if; | |
7515 | ||
feff2f05 | 7516 | -- We reset the number of saved checks to zero, and also modify all |
7517 | -- stack entries for statement ranges to indicate that the number of | |
7518 | -- checks at each level is now zero. | |
9dfe12ae | 7519 | |
7520 | Num_Saved_Checks := 0; | |
7521 | ||
96da3284 | 7522 | -- Note: the Int'Min here avoids any possibility of J being out of |
7523 | -- range when called from e.g. Conditional_Statements_Begin. | |
7524 | ||
7525 | for J in 1 .. Int'Min (Saved_Checks_TOS, Saved_Checks_Stack'Last) loop | |
9dfe12ae | 7526 | Saved_Checks_Stack (J) := 0; |
7527 | end loop; | |
7528 | end Kill_All_Checks; | |
7529 | ||
7530 | ----------------- | |
7531 | -- Kill_Checks -- | |
7532 | ----------------- | |
7533 | ||
7534 | procedure Kill_Checks (V : Entity_Id) is | |
7535 | begin | |
7536 | if Debug_Flag_CC then | |
7537 | w ("Kill_Checks for entity", Int (V)); | |
7538 | end if; | |
7539 | ||
7540 | for J in 1 .. Num_Saved_Checks loop | |
7541 | if Saved_Checks (J).Entity = V then | |
7542 | if Debug_Flag_CC then | |
7543 | w (" Checks killed for saved check ", J); | |
7544 | end if; | |
7545 | ||
7546 | Saved_Checks (J).Killed := True; | |
7547 | end if; | |
7548 | end loop; | |
7549 | end Kill_Checks; | |
7550 | ||
ee6ba406 | 7551 | ------------------------------ |
7552 | -- Length_Checks_Suppressed -- | |
7553 | ------------------------------ | |
7554 | ||
7555 | function Length_Checks_Suppressed (E : Entity_Id) return Boolean is | |
7556 | begin | |
9dfe12ae | 7557 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
7558 | return Is_Check_Suppressed (E, Length_Check); | |
7559 | else | |
fafc6b97 | 7560 | return Scope_Suppress.Suppress (Length_Check); |
9dfe12ae | 7561 | end if; |
ee6ba406 | 7562 | end Length_Checks_Suppressed; |
7563 | ||
3cce7f32 | 7564 | ----------------------- |
7565 | -- Make_Bignum_Block -- | |
7566 | ----------------------- | |
7567 | ||
7568 | function Make_Bignum_Block (Loc : Source_Ptr) return Node_Id is | |
7569 | M : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uM); | |
3cce7f32 | 7570 | begin |
7571 | return | |
7572 | Make_Block_Statement (Loc, | |
97c15ab0 | 7573 | Declarations => |
7574 | New_List (Build_SS_Mark_Call (Loc, M)), | |
3cce7f32 | 7575 | Handled_Statement_Sequence => |
7576 | Make_Handled_Sequence_Of_Statements (Loc, | |
97c15ab0 | 7577 | Statements => New_List (Build_SS_Release_Call (Loc, M)))); |
3cce7f32 | 7578 | end Make_Bignum_Block; |
7579 | ||
0df9d43f | 7580 | ---------------------------------- |
7581 | -- Minimize_Eliminate_Overflows -- | |
7582 | ---------------------------------- | |
3cce7f32 | 7583 | |
f32c377d | 7584 | -- This is a recursive routine that is called at the top of an expression |
7585 | -- tree to properly process overflow checking for a whole subtree by making | |
7586 | -- recursive calls to process operands. This processing may involve the use | |
7587 | -- of bignum or long long integer arithmetic, which will change the types | |
7588 | -- of operands and results. That's why we can't do this bottom up (since | |
21a55437 | 7589 | -- it would interfere with semantic analysis). |
f32c377d | 7590 | |
21a55437 | 7591 | -- What happens is that if MINIMIZED/ELIMINATED mode is in effect then |
0df9d43f | 7592 | -- the operator expansion routines, as well as the expansion routines for |
7593 | -- if/case expression, do nothing (for the moment) except call the routine | |
7594 | -- to apply the overflow check (Apply_Arithmetic_Overflow_Check). That | |
7595 | -- routine does nothing for non top-level nodes, so at the point where the | |
7596 | -- call is made for the top level node, the entire expression subtree has | |
7597 | -- not been expanded, or processed for overflow. All that has to happen as | |
7598 | -- a result of the top level call to this routine. | |
f32c377d | 7599 | |
7600 | -- As noted above, the overflow processing works by making recursive calls | |
7601 | -- for the operands, and figuring out what to do, based on the processing | |
7602 | -- of these operands (e.g. if a bignum operand appears, the parent op has | |
7603 | -- to be done in bignum mode), and the determined ranges of the operands. | |
7604 | ||
7605 | -- After possible rewriting of a constituent subexpression node, a call is | |
4fb5f0a0 | 7606 | -- made to either reexpand the node (if nothing has changed) or reanalyze |
21a55437 | 7607 | -- the node (if it has been modified by the overflow check processing). The |
7608 | -- Analyzed_Flag is set to False before the reexpand/reanalyze. To avoid | |
7609 | -- a recursive call into the whole overflow apparatus, an important rule | |
0df9d43f | 7610 | -- for this call is that the overflow handling mode must be temporarily set |
7611 | -- to STRICT. | |
f32c377d | 7612 | |
0df9d43f | 7613 | procedure Minimize_Eliminate_Overflows |
61016a7a | 7614 | (N : Node_Id; |
7615 | Lo : out Uint; | |
7616 | Hi : out Uint; | |
7617 | Top_Level : Boolean) | |
3cce7f32 | 7618 | is |
0326b4d4 | 7619 | Rtyp : constant Entity_Id := Etype (N); |
7620 | pragma Assert (Is_Signed_Integer_Type (Rtyp)); | |
7621 | -- Result type, must be a signed integer type | |
3cce7f32 | 7622 | |
db415383 | 7623 | Check_Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
3cce7f32 | 7624 | pragma Assert (Check_Mode in Minimized_Or_Eliminated); |
7625 | ||
7626 | Loc : constant Source_Ptr := Sloc (N); | |
7627 | ||
7628 | Rlo, Rhi : Uint; | |
0326b4d4 | 7629 | -- Ranges of values for right operand (operator case) |
3cce7f32 | 7630 | |
7631 | Llo, Lhi : Uint; | |
0326b4d4 | 7632 | -- Ranges of values for left operand (operator case) |
3cce7f32 | 7633 | |
49b3a812 | 7634 | LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); |
7635 | -- Operands and results are of this type when we convert | |
7636 | ||
0326b4d4 | 7637 | LLLo : constant Uint := Intval (Type_Low_Bound (LLIB)); |
7638 | LLHi : constant Uint := Intval (Type_High_Bound (LLIB)); | |
3cce7f32 | 7639 | -- Bounds of Long_Long_Integer |
7640 | ||
7641 | Binary : constant Boolean := Nkind (N) in N_Binary_Op; | |
7642 | -- Indicates binary operator case | |
7643 | ||
7644 | OK : Boolean; | |
7645 | -- Used in call to Determine_Range | |
7646 | ||
61016a7a | 7647 | Bignum_Operands : Boolean; |
7648 | -- Set True if one or more operands is already of type Bignum, meaning | |
7649 | -- that for sure (regardless of Top_Level setting) we are committed to | |
0326b4d4 | 7650 | -- doing the operation in Bignum mode (or in the case of a case or if |
21a55437 | 7651 | -- expression, converting all the dependent expressions to Bignum). |
0326b4d4 | 7652 | |
7653 | Long_Long_Integer_Operands : Boolean; | |
21a55437 | 7654 | -- Set True if one or more operands is already of type Long_Long_Integer |
0326b4d4 | 7655 | -- which means that if the result is known to be in the result type |
7656 | -- range, then we must convert such operands back to the result type. | |
0df9d43f | 7657 | |
7658 | procedure Reanalyze (Typ : Entity_Id; Suppress : Boolean := False); | |
7659 | -- This is called when we have modified the node and we therefore need | |
7660 | -- to reanalyze it. It is important that we reset the mode to STRICT for | |
7661 | -- this reanalysis, since if we leave it in MINIMIZED or ELIMINATED mode | |
39a0c1d3 | 7662 | -- we would reenter this routine recursively which would not be good. |
0df9d43f | 7663 | -- The argument Suppress is set True if we also want to suppress |
7664 | -- overflow checking for the reexpansion (this is set when we know | |
7665 | -- overflow is not possible). Typ is the type for the reanalysis. | |
7666 | ||
7667 | procedure Reexpand (Suppress : Boolean := False); | |
7668 | -- This is like Reanalyze, but does not do the Analyze step, it only | |
7669 | -- does a reexpansion. We do this reexpansion in STRICT mode, so that | |
7670 | -- instead of reentering the MINIMIZED/ELIMINATED mode processing, we | |
7671 | -- follow the normal expansion path (e.g. converting A**4 to A**2**2). | |
7672 | -- Note that skipping reanalysis is not just an optimization, testing | |
7673 | -- has showed up several complex cases in which reanalyzing an already | |
7674 | -- analyzed node causes incorrect behavior. | |
4fb5f0a0 | 7675 | |
0326b4d4 | 7676 | function In_Result_Range return Boolean; |
7677 | -- Returns True iff Lo .. Hi are within range of the result type | |
61016a7a | 7678 | |
2fe22c69 | 7679 | procedure Max (A : in out Uint; B : Uint); |
21a55437 | 7680 | -- If A is No_Uint, sets A to B, else to UI_Max (A, B) |
2fe22c69 | 7681 | |
7682 | procedure Min (A : in out Uint; B : Uint); | |
21a55437 | 7683 | -- If A is No_Uint, sets A to B, else to UI_Min (A, B) |
2fe22c69 | 7684 | |
0326b4d4 | 7685 | --------------------- |
7686 | -- In_Result_Range -- | |
7687 | --------------------- | |
7688 | ||
7689 | function In_Result_Range return Boolean is | |
7690 | begin | |
f32c377d | 7691 | if Lo = No_Uint or else Hi = No_Uint then |
7692 | return False; | |
7693 | ||
cda40848 | 7694 | elsif Is_OK_Static_Subtype (Etype (N)) then |
0326b4d4 | 7695 | return Lo >= Expr_Value (Type_Low_Bound (Rtyp)) |
7696 | and then | |
7697 | Hi <= Expr_Value (Type_High_Bound (Rtyp)); | |
f32c377d | 7698 | |
0326b4d4 | 7699 | else |
7700 | return Lo >= Expr_Value (Type_Low_Bound (Base_Type (Rtyp))) | |
7701 | and then | |
7702 | Hi <= Expr_Value (Type_High_Bound (Base_Type (Rtyp))); | |
7703 | end if; | |
7704 | end In_Result_Range; | |
7705 | ||
2fe22c69 | 7706 | --------- |
7707 | -- Max -- | |
7708 | --------- | |
7709 | ||
7710 | procedure Max (A : in out Uint; B : Uint) is | |
7711 | begin | |
7712 | if A = No_Uint or else B > A then | |
7713 | A := B; | |
7714 | end if; | |
7715 | end Max; | |
7716 | ||
7717 | --------- | |
7718 | -- Min -- | |
7719 | --------- | |
7720 | ||
7721 | procedure Min (A : in out Uint; B : Uint) is | |
7722 | begin | |
7723 | if A = No_Uint or else B < A then | |
7724 | A := B; | |
7725 | end if; | |
7726 | end Min; | |
7727 | ||
0df9d43f | 7728 | --------------- |
7729 | -- Reanalyze -- | |
7730 | --------------- | |
7731 | ||
7732 | procedure Reanalyze (Typ : Entity_Id; Suppress : Boolean := False) is | |
db415383 | 7733 | Svg : constant Overflow_Mode_Type := |
7734 | Scope_Suppress.Overflow_Mode_General; | |
7735 | Sva : constant Overflow_Mode_Type := | |
7736 | Scope_Suppress.Overflow_Mode_Assertions; | |
0df9d43f | 7737 | Svo : constant Boolean := |
7738 | Scope_Suppress.Suppress (Overflow_Check); | |
7739 | ||
7740 | begin | |
db415383 | 7741 | Scope_Suppress.Overflow_Mode_General := Strict; |
7742 | Scope_Suppress.Overflow_Mode_Assertions := Strict; | |
0df9d43f | 7743 | |
7744 | if Suppress then | |
7745 | Scope_Suppress.Suppress (Overflow_Check) := True; | |
7746 | end if; | |
7747 | ||
7748 | Analyze_And_Resolve (N, Typ); | |
7749 | ||
7750 | Scope_Suppress.Suppress (Overflow_Check) := Svo; | |
db415383 | 7751 | Scope_Suppress.Overflow_Mode_General := Svg; |
7752 | Scope_Suppress.Overflow_Mode_Assertions := Sva; | |
0df9d43f | 7753 | end Reanalyze; |
7754 | ||
4fb5f0a0 | 7755 | -------------- |
7756 | -- Reexpand -- | |
7757 | -------------- | |
7758 | ||
0df9d43f | 7759 | procedure Reexpand (Suppress : Boolean := False) is |
db415383 | 7760 | Svg : constant Overflow_Mode_Type := |
7761 | Scope_Suppress.Overflow_Mode_General; | |
7762 | Sva : constant Overflow_Mode_Type := | |
7763 | Scope_Suppress.Overflow_Mode_Assertions; | |
0df9d43f | 7764 | Svo : constant Boolean := |
7765 | Scope_Suppress.Suppress (Overflow_Check); | |
7766 | ||
4fb5f0a0 | 7767 | begin |
db415383 | 7768 | Scope_Suppress.Overflow_Mode_General := Strict; |
7769 | Scope_Suppress.Overflow_Mode_Assertions := Strict; | |
4fb5f0a0 | 7770 | Set_Analyzed (N, False); |
0df9d43f | 7771 | |
7772 | if Suppress then | |
7773 | Scope_Suppress.Suppress (Overflow_Check) := True; | |
7774 | end if; | |
7775 | ||
4fb5f0a0 | 7776 | Expand (N); |
0df9d43f | 7777 | |
7778 | Scope_Suppress.Suppress (Overflow_Check) := Svo; | |
db415383 | 7779 | Scope_Suppress.Overflow_Mode_General := Svg; |
7780 | Scope_Suppress.Overflow_Mode_Assertions := Sva; | |
4fb5f0a0 | 7781 | end Reexpand; |
7782 | ||
0df9d43f | 7783 | -- Start of processing for Minimize_Eliminate_Overflows |
2fe22c69 | 7784 | |
3cce7f32 | 7785 | begin |
0326b4d4 | 7786 | -- Case where we do not have a signed integer arithmetic operation |
3cce7f32 | 7787 | |
7788 | if not Is_Signed_Integer_Arithmetic_Op (N) then | |
7789 | ||
7790 | -- Use the normal Determine_Range routine to get the range. We | |
7791 | -- don't require operands to be valid, invalid values may result in | |
7792 | -- rubbish results where the result has not been properly checked for | |
39a0c1d3 | 7793 | -- overflow, that's fine. |
3cce7f32 | 7794 | |
7795 | Determine_Range (N, OK, Lo, Hi, Assume_Valid => False); | |
7796 | ||
21a55437 | 7797 | -- If Determine_Range did not work (can this in fact happen? Not |
3cce7f32 | 7798 | -- clear but might as well protect), use type bounds. |
7799 | ||
7800 | if not OK then | |
7801 | Lo := Intval (Type_Low_Bound (Base_Type (Etype (N)))); | |
7802 | Hi := Intval (Type_High_Bound (Base_Type (Etype (N)))); | |
7803 | end if; | |
7804 | ||
7805 | -- If we don't have a binary operator, all we have to do is to set | |
20cf157b | 7806 | -- the Hi/Lo range, so we are done. |
3cce7f32 | 7807 | |
7808 | return; | |
7809 | ||
0326b4d4 | 7810 | -- Processing for if expression |
7811 | ||
92f1631f | 7812 | elsif Nkind (N) = N_If_Expression then |
0326b4d4 | 7813 | declare |
7814 | Then_DE : constant Node_Id := Next (First (Expressions (N))); | |
7815 | Else_DE : constant Node_Id := Next (Then_DE); | |
7816 | ||
7817 | begin | |
7818 | Bignum_Operands := False; | |
7819 | ||
0df9d43f | 7820 | Minimize_Eliminate_Overflows |
0326b4d4 | 7821 | (Then_DE, Lo, Hi, Top_Level => False); |
7822 | ||
7823 | if Lo = No_Uint then | |
7824 | Bignum_Operands := True; | |
7825 | end if; | |
7826 | ||
0df9d43f | 7827 | Minimize_Eliminate_Overflows |
0326b4d4 | 7828 | (Else_DE, Rlo, Rhi, Top_Level => False); |
7829 | ||
7830 | if Rlo = No_Uint then | |
7831 | Bignum_Operands := True; | |
7832 | else | |
7833 | Long_Long_Integer_Operands := | |
7834 | Etype (Then_DE) = LLIB or else Etype (Else_DE) = LLIB; | |
7835 | ||
7836 | Min (Lo, Rlo); | |
7837 | Max (Hi, Rhi); | |
7838 | end if; | |
7839 | ||
21a55437 | 7840 | -- If at least one of our operands is now Bignum, we must rebuild |
7841 | -- the if expression to use Bignum operands. We will analyze the | |
0326b4d4 | 7842 | -- rebuilt if expression with overflow checks off, since once we |
39a0c1d3 | 7843 | -- are in bignum mode, we are all done with overflow checks. |
0326b4d4 | 7844 | |
7845 | if Bignum_Operands then | |
7846 | Rewrite (N, | |
92f1631f | 7847 | Make_If_Expression (Loc, |
0326b4d4 | 7848 | Expressions => New_List ( |
7849 | Remove_Head (Expressions (N)), | |
7850 | Convert_To_Bignum (Then_DE), | |
7851 | Convert_To_Bignum (Else_DE)), | |
7852 | Is_Elsif => Is_Elsif (N))); | |
7853 | ||
0df9d43f | 7854 | Reanalyze (RTE (RE_Bignum), Suppress => True); |
0326b4d4 | 7855 | |
7856 | -- If we have no Long_Long_Integer operands, then we are in result | |
7857 | -- range, since it means that none of our operands felt the need | |
7858 | -- to worry about overflow (otherwise it would have already been | |
4fb5f0a0 | 7859 | -- converted to long long integer or bignum). We reexpand to |
7860 | -- complete the expansion of the if expression (but we do not | |
7861 | -- need to reanalyze). | |
0326b4d4 | 7862 | |
7863 | elsif not Long_Long_Integer_Operands then | |
7864 | Set_Do_Overflow_Check (N, False); | |
0df9d43f | 7865 | Reexpand; |
0326b4d4 | 7866 | |
7867 | -- Otherwise convert us to long long integer mode. Note that we | |
7868 | -- don't need any further overflow checking at this level. | |
7869 | ||
7870 | else | |
7871 | Convert_To_And_Rewrite (LLIB, Then_DE); | |
7872 | Convert_To_And_Rewrite (LLIB, Else_DE); | |
7873 | Set_Etype (N, LLIB); | |
f32c377d | 7874 | |
7875 | -- Now reanalyze with overflow checks off | |
7876 | ||
0326b4d4 | 7877 | Set_Do_Overflow_Check (N, False); |
0df9d43f | 7878 | Reanalyze (LLIB, Suppress => True); |
0326b4d4 | 7879 | end if; |
7880 | end; | |
7881 | ||
7882 | return; | |
7883 | ||
7884 | -- Here for case expression | |
7885 | ||
7886 | elsif Nkind (N) = N_Case_Expression then | |
7887 | Bignum_Operands := False; | |
7888 | Long_Long_Integer_Operands := False; | |
0326b4d4 | 7889 | |
7890 | declare | |
f32c377d | 7891 | Alt : Node_Id; |
0326b4d4 | 7892 | |
7893 | begin | |
7894 | -- Loop through expressions applying recursive call | |
7895 | ||
7896 | Alt := First (Alternatives (N)); | |
7897 | while Present (Alt) loop | |
7898 | declare | |
7899 | Aexp : constant Node_Id := Expression (Alt); | |
7900 | ||
7901 | begin | |
0df9d43f | 7902 | Minimize_Eliminate_Overflows |
0326b4d4 | 7903 | (Aexp, Lo, Hi, Top_Level => False); |
7904 | ||
7905 | if Lo = No_Uint then | |
7906 | Bignum_Operands := True; | |
7907 | elsif Etype (Aexp) = LLIB then | |
7908 | Long_Long_Integer_Operands := True; | |
7909 | end if; | |
7910 | end; | |
7911 | ||
7912 | Next (Alt); | |
7913 | end loop; | |
7914 | ||
7915 | -- If we have no bignum or long long integer operands, it means | |
7916 | -- that none of our dependent expressions could raise overflow. | |
7917 | -- In this case, we simply return with no changes except for | |
7918 | -- resetting the overflow flag, since we are done with overflow | |
4fb5f0a0 | 7919 | -- checks for this node. We will reexpand to get the needed |
7920 | -- expansion for the case expression, but we do not need to | |
21a55437 | 7921 | -- reanalyze, since nothing has changed. |
0326b4d4 | 7922 | |
f32c377d | 7923 | if not (Bignum_Operands or Long_Long_Integer_Operands) then |
0326b4d4 | 7924 | Set_Do_Overflow_Check (N, False); |
0df9d43f | 7925 | Reexpand (Suppress => True); |
0326b4d4 | 7926 | |
7927 | -- Otherwise we are going to rebuild the case expression using | |
7928 | -- either bignum or long long integer operands throughout. | |
7929 | ||
7930 | else | |
f32c377d | 7931 | declare |
7932 | Rtype : Entity_Id; | |
7933 | New_Alts : List_Id; | |
7934 | New_Exp : Node_Id; | |
7935 | ||
7936 | begin | |
7937 | New_Alts := New_List; | |
7938 | Alt := First (Alternatives (N)); | |
7939 | while Present (Alt) loop | |
7940 | if Bignum_Operands then | |
7941 | New_Exp := Convert_To_Bignum (Expression (Alt)); | |
7942 | Rtype := RTE (RE_Bignum); | |
7943 | else | |
7944 | New_Exp := Convert_To (LLIB, Expression (Alt)); | |
7945 | Rtype := LLIB; | |
7946 | end if; | |
0326b4d4 | 7947 | |
f32c377d | 7948 | Append_To (New_Alts, |
7949 | Make_Case_Expression_Alternative (Sloc (Alt), | |
7950 | Actions => No_List, | |
7951 | Discrete_Choices => Discrete_Choices (Alt), | |
7952 | Expression => New_Exp)); | |
0326b4d4 | 7953 | |
f32c377d | 7954 | Next (Alt); |
7955 | end loop; | |
0326b4d4 | 7956 | |
f32c377d | 7957 | Rewrite (N, |
7958 | Make_Case_Expression (Loc, | |
7959 | Expression => Expression (N), | |
7960 | Alternatives => New_Alts)); | |
0326b4d4 | 7961 | |
0df9d43f | 7962 | Reanalyze (Rtype, Suppress => True); |
f32c377d | 7963 | end; |
0326b4d4 | 7964 | end if; |
7965 | end; | |
7966 | ||
7967 | return; | |
7968 | end if; | |
7969 | ||
7970 | -- If we have an arithmetic operator we make recursive calls on the | |
3cce7f32 | 7971 | -- operands to get the ranges (and to properly process the subtree |
20cf157b | 7972 | -- that lies below us). |
3cce7f32 | 7973 | |
0df9d43f | 7974 | Minimize_Eliminate_Overflows |
0326b4d4 | 7975 | (Right_Opnd (N), Rlo, Rhi, Top_Level => False); |
3cce7f32 | 7976 | |
0326b4d4 | 7977 | if Binary then |
0df9d43f | 7978 | Minimize_Eliminate_Overflows |
0326b4d4 | 7979 | (Left_Opnd (N), Llo, Lhi, Top_Level => False); |
3cce7f32 | 7980 | end if; |
7981 | ||
f32c377d | 7982 | -- Record if we have Long_Long_Integer operands |
7983 | ||
7984 | Long_Long_Integer_Operands := | |
7985 | Etype (Right_Opnd (N)) = LLIB | |
7986 | or else (Binary and then Etype (Left_Opnd (N)) = LLIB); | |
7987 | ||
7988 | -- If either operand is a bignum, then result will be a bignum and we | |
7989 | -- don't need to do any range analysis. As previously discussed we could | |
7990 | -- do range analysis in such cases, but it could mean working with giant | |
7991 | -- numbers at compile time for very little gain (the number of cases | |
21a55437 | 7992 | -- in which we could slip back from bignum mode is small). |
3cce7f32 | 7993 | |
7994 | if Rlo = No_Uint or else (Binary and then Llo = No_Uint) then | |
7995 | Lo := No_Uint; | |
7996 | Hi := No_Uint; | |
61016a7a | 7997 | Bignum_Operands := True; |
3cce7f32 | 7998 | |
7999 | -- Otherwise compute result range | |
8000 | ||
8001 | else | |
61016a7a | 8002 | Bignum_Operands := False; |
8003 | ||
3cce7f32 | 8004 | case Nkind (N) is |
8005 | ||
8006 | -- Absolute value | |
8007 | ||
8008 | when N_Op_Abs => | |
8009 | Lo := Uint_0; | |
de922300 | 8010 | Hi := UI_Max (abs Rlo, abs Rhi); |
3cce7f32 | 8011 | |
8012 | -- Addition | |
8013 | ||
8014 | when N_Op_Add => | |
8015 | Lo := Llo + Rlo; | |
8016 | Hi := Lhi + Rhi; | |
8017 | ||
8018 | -- Division | |
8019 | ||
8020 | when N_Op_Divide => | |
2fe22c69 | 8021 | |
5f4275e1 | 8022 | -- If the right operand can only be zero, set 0..0 |
2fe22c69 | 8023 | |
5f4275e1 | 8024 | if Rlo = 0 and then Rhi = 0 then |
8025 | Lo := Uint_0; | |
8026 | Hi := Uint_0; | |
2fe22c69 | 8027 | |
5f4275e1 | 8028 | -- Possible bounds of division must come from dividing end |
8029 | -- values of the input ranges (four possibilities), provided | |
8030 | -- zero is not included in the possible values of the right | |
8031 | -- operand. | |
8032 | ||
8033 | -- Otherwise, we just consider two intervals of values for | |
8034 | -- the right operand: the interval of negative values (up to | |
8035 | -- -1) and the interval of positive values (starting at 1). | |
8036 | -- Since division by 1 is the identity, and division by -1 | |
8037 | -- is negation, we get all possible bounds of division in that | |
8038 | -- case by considering: | |
8039 | -- - all values from the division of end values of input | |
8040 | -- ranges; | |
8041 | -- - the end values of the left operand; | |
8042 | -- - the negation of the end values of the left operand. | |
2fe22c69 | 8043 | |
5f4275e1 | 8044 | else |
8045 | declare | |
8046 | Mrk : constant Uintp.Save_Mark := Mark; | |
8047 | -- Mark so we can release the RR and Ev values | |
2fe22c69 | 8048 | |
5f4275e1 | 8049 | Ev1 : Uint; |
8050 | Ev2 : Uint; | |
8051 | Ev3 : Uint; | |
8052 | Ev4 : Uint; | |
2fe22c69 | 8053 | |
5f4275e1 | 8054 | begin |
8055 | -- Discard extreme values of zero for the divisor, since | |
8056 | -- they will simply result in an exception in any case. | |
2fe22c69 | 8057 | |
5f4275e1 | 8058 | if Rlo = 0 then |
8059 | Rlo := Uint_1; | |
8060 | elsif Rhi = 0 then | |
8061 | Rhi := -Uint_1; | |
2fe22c69 | 8062 | end if; |
2fe22c69 | 8063 | |
5f4275e1 | 8064 | -- Compute possible bounds coming from dividing end |
8065 | -- values of the input ranges. | |
2fe22c69 | 8066 | |
5f4275e1 | 8067 | Ev1 := Llo / Rlo; |
8068 | Ev2 := Llo / Rhi; | |
8069 | Ev3 := Lhi / Rlo; | |
8070 | Ev4 := Lhi / Rhi; | |
2fe22c69 | 8071 | |
5f4275e1 | 8072 | Lo := UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4)); |
8073 | Hi := UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4)); | |
2fe22c69 | 8074 | |
5f4275e1 | 8075 | -- If the right operand can be both negative or positive, |
8076 | -- include the end values of the left operand in the | |
8077 | -- extreme values, as well as their negation. | |
2fe22c69 | 8078 | |
5f4275e1 | 8079 | if Rlo < 0 and then Rhi > 0 then |
8080 | Ev1 := Llo; | |
8081 | Ev2 := -Llo; | |
8082 | Ev3 := Lhi; | |
8083 | Ev4 := -Lhi; | |
2fe22c69 | 8084 | |
5f4275e1 | 8085 | Min (Lo, |
8086 | UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4))); | |
8087 | Max (Hi, | |
8088 | UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4))); | |
2fe22c69 | 8089 | end if; |
2fe22c69 | 8090 | |
5f4275e1 | 8091 | -- Release the RR and Ev values |
2fe22c69 | 8092 | |
5f4275e1 | 8093 | Release_And_Save (Mrk, Lo, Hi); |
8094 | end; | |
8095 | end if; | |
3cce7f32 | 8096 | |
8097 | -- Exponentiation | |
8098 | ||
8099 | when N_Op_Expon => | |
de922300 | 8100 | |
8101 | -- Discard negative values for the exponent, since they will | |
8102 | -- simply result in an exception in any case. | |
8103 | ||
8104 | if Rhi < 0 then | |
8105 | Rhi := Uint_0; | |
8106 | elsif Rlo < 0 then | |
8107 | Rlo := Uint_0; | |
8108 | end if; | |
8109 | ||
8110 | -- Estimate number of bits in result before we go computing | |
8111 | -- giant useless bounds. Basically the number of bits in the | |
8112 | -- result is the number of bits in the base multiplied by the | |
8113 | -- value of the exponent. If this is big enough that the result | |
8114 | -- definitely won't fit in Long_Long_Integer, switch to bignum | |
8115 | -- mode immediately, and avoid computing giant bounds. | |
8116 | ||
8117 | -- The comparison here is approximate, but conservative, it | |
8118 | -- only clicks on cases that are sure to exceed the bounds. | |
8119 | ||
8120 | if Num_Bits (UI_Max (abs Llo, abs Lhi)) * Rhi + 1 > 100 then | |
8121 | Lo := No_Uint; | |
8122 | Hi := No_Uint; | |
8123 | ||
8124 | -- If right operand is zero then result is 1 | |
8125 | ||
8126 | elsif Rhi = 0 then | |
8127 | Lo := Uint_1; | |
8128 | Hi := Uint_1; | |
8129 | ||
8130 | else | |
8131 | -- High bound comes either from exponentiation of largest | |
5f4275e1 | 8132 | -- positive value to largest exponent value, or from |
8133 | -- the exponentiation of most negative value to an | |
8134 | -- even exponent. | |
de922300 | 8135 | |
8136 | declare | |
8137 | Hi1, Hi2 : Uint; | |
8138 | ||
8139 | begin | |
5f4275e1 | 8140 | if Lhi > 0 then |
de922300 | 8141 | Hi1 := Lhi ** Rhi; |
8142 | else | |
8143 | Hi1 := Uint_0; | |
8144 | end if; | |
8145 | ||
8146 | if Llo < 0 then | |
8147 | if Rhi mod 2 = 0 then | |
de922300 | 8148 | Hi2 := Llo ** Rhi; |
5f4275e1 | 8149 | else |
8150 | Hi2 := Llo ** (Rhi - 1); | |
de922300 | 8151 | end if; |
8152 | else | |
8153 | Hi2 := Uint_0; | |
8154 | end if; | |
8155 | ||
8156 | Hi := UI_Max (Hi1, Hi2); | |
8157 | end; | |
8158 | ||
8159 | -- Result can only be negative if base can be negative | |
8160 | ||
8161 | if Llo < 0 then | |
21a55437 | 8162 | if Rhi mod 2 = 0 then |
de922300 | 8163 | Lo := Llo ** (Rhi - 1); |
8164 | else | |
8165 | Lo := Llo ** Rhi; | |
8166 | end if; | |
8167 | ||
21a55437 | 8168 | -- Otherwise low bound is minimum ** minimum |
de922300 | 8169 | |
8170 | else | |
8171 | Lo := Llo ** Rlo; | |
8172 | end if; | |
8173 | end if; | |
3cce7f32 | 8174 | |
8175 | -- Negation | |
8176 | ||
8177 | when N_Op_Minus => | |
8178 | Lo := -Rhi; | |
8179 | Hi := -Rlo; | |
8180 | ||
8181 | -- Mod | |
8182 | ||
8183 | when N_Op_Mod => | |
2fe22c69 | 8184 | declare |
5f4275e1 | 8185 | Maxabs : constant Uint := UI_Max (abs Rlo, abs Rhi) - 1; |
2fe22c69 | 8186 | -- This is the maximum absolute value of the result |
8187 | ||
8188 | begin | |
8189 | Lo := Uint_0; | |
8190 | Hi := Uint_0; | |
8191 | ||
8192 | -- The result depends only on the sign and magnitude of | |
8193 | -- the right operand, it does not depend on the sign or | |
8194 | -- magnitude of the left operand. | |
8195 | ||
8196 | if Rlo < 0 then | |
8197 | Lo := -Maxabs; | |
8198 | end if; | |
8199 | ||
8200 | if Rhi > 0 then | |
8201 | Hi := Maxabs; | |
8202 | end if; | |
8203 | end; | |
3cce7f32 | 8204 | |
8205 | -- Multiplication | |
8206 | ||
8207 | when N_Op_Multiply => | |
49b3a812 | 8208 | |
8209 | -- Possible bounds of multiplication must come from multiplying | |
8210 | -- end values of the input ranges (four possibilities). | |
8211 | ||
8212 | declare | |
8213 | Mrk : constant Uintp.Save_Mark := Mark; | |
8214 | -- Mark so we can release the Ev values | |
8215 | ||
8216 | Ev1 : constant Uint := Llo * Rlo; | |
8217 | Ev2 : constant Uint := Llo * Rhi; | |
8218 | Ev3 : constant Uint := Lhi * Rlo; | |
8219 | Ev4 : constant Uint := Lhi * Rhi; | |
8220 | ||
8221 | begin | |
8222 | Lo := UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4)); | |
8223 | Hi := UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4)); | |
8224 | ||
8225 | -- Release the Ev values | |
8226 | ||
8227 | Release_And_Save (Mrk, Lo, Hi); | |
8228 | end; | |
3cce7f32 | 8229 | |
8230 | -- Plus operator (affirmation) | |
8231 | ||
8232 | when N_Op_Plus => | |
8233 | Lo := Rlo; | |
8234 | Hi := Rhi; | |
8235 | ||
8236 | -- Remainder | |
8237 | ||
8238 | when N_Op_Rem => | |
2fe22c69 | 8239 | declare |
5f4275e1 | 8240 | Maxabs : constant Uint := UI_Max (abs Rlo, abs Rhi) - 1; |
2fe22c69 | 8241 | -- This is the maximum absolute value of the result. Note |
5f4275e1 | 8242 | -- that the result range does not depend on the sign of the |
8243 | -- right operand. | |
2fe22c69 | 8244 | |
8245 | begin | |
8246 | Lo := Uint_0; | |
8247 | Hi := Uint_0; | |
8248 | ||
8249 | -- Case of left operand negative, which results in a range | |
8250 | -- of -Maxabs .. 0 for those negative values. If there are | |
8251 | -- no negative values then Lo value of result is always 0. | |
8252 | ||
8253 | if Llo < 0 then | |
8254 | Lo := -Maxabs; | |
8255 | end if; | |
8256 | ||
8257 | -- Case of left operand positive | |
8258 | ||
8259 | if Lhi > 0 then | |
8260 | Hi := Maxabs; | |
8261 | end if; | |
8262 | end; | |
3cce7f32 | 8263 | |
8264 | -- Subtract | |
8265 | ||
8266 | when N_Op_Subtract => | |
8267 | Lo := Llo - Rhi; | |
8268 | Hi := Lhi - Rlo; | |
8269 | ||
8270 | -- Nothing else should be possible | |
8271 | ||
8272 | when others => | |
8273 | raise Program_Error; | |
3cce7f32 | 8274 | end case; |
8275 | end if; | |
8276 | ||
4fb5f0a0 | 8277 | -- Here for the case where we have not rewritten anything (no bignum |
21a55437 | 8278 | -- operands or long long integer operands), and we know the result. |
8279 | -- If we know we are in the result range, and we do not have Bignum | |
8280 | -- operands or Long_Long_Integer operands, we can just reexpand with | |
8281 | -- overflow checks turned off (since we know we cannot have overflow). | |
8282 | -- As always the reexpansion is required to complete expansion of the | |
8283 | -- operator, but we do not need to reanalyze, and we prevent recursion | |
8284 | -- by suppressing the check. | |
f32c377d | 8285 | |
8286 | if not (Bignum_Operands or Long_Long_Integer_Operands) | |
8287 | and then In_Result_Range | |
8288 | then | |
8289 | Set_Do_Overflow_Check (N, False); | |
0df9d43f | 8290 | Reexpand (Suppress => True); |
f32c377d | 8291 | return; |
8292 | ||
8293 | -- Here we know that we are not in the result range, and in the general | |
21a55437 | 8294 | -- case we will move into either the Bignum or Long_Long_Integer domain |
8295 | -- to compute the result. However, there is one exception. If we are | |
8296 | -- at the top level, and we do not have Bignum or Long_Long_Integer | |
8297 | -- operands, we will have to immediately convert the result back to | |
8298 | -- the result type, so there is no point in Bignum/Long_Long_Integer | |
8299 | -- fiddling. | |
f32c377d | 8300 | |
8301 | elsif Top_Level | |
8302 | and then not (Bignum_Operands or Long_Long_Integer_Operands) | |
b6a8f264 | 8303 | |
8304 | -- One further refinement. If we are at the top level, but our parent | |
8305 | -- is a type conversion, then go into bignum or long long integer node | |
8306 | -- since the result will be converted to that type directly without | |
8307 | -- going through the result type, and we may avoid an overflow. This | |
8308 | -- is the case for example of Long_Long_Integer (A ** 4), where A is | |
8309 | -- of type Integer, and the result A ** 4 fits in Long_Long_Integer | |
8310 | -- but does not fit in Integer. | |
8311 | ||
8312 | and then Nkind (Parent (N)) /= N_Type_Conversion | |
f32c377d | 8313 | then |
0df9d43f | 8314 | -- Here keep original types, but we need to complete analysis |
f32c377d | 8315 | |
8316 | -- One subtlety. We can't just go ahead and do an analyze operation | |
21a55437 | 8317 | -- here because it will cause recursion into the whole MINIMIZED/ |
8318 | -- ELIMINATED overflow processing which is not what we want. Here | |
f32c377d | 8319 | -- we are at the top level, and we need a check against the result |
39a0c1d3 | 8320 | -- mode (i.e. we want to use STRICT mode). So do exactly that. |
4fb5f0a0 | 8321 | -- Also, we have not modified the node, so this is a case where |
8322 | -- we need to reexpand, but not reanalyze. | |
f32c377d | 8323 | |
0df9d43f | 8324 | Reexpand; |
f32c377d | 8325 | return; |
8326 | ||
8327 | -- Cases where we do the operation in Bignum mode. This happens either | |
3cce7f32 | 8328 | -- because one of our operands is in Bignum mode already, or because |
de922300 | 8329 | -- the computed bounds are outside the bounds of Long_Long_Integer, |
8330 | -- which in some cases can be indicated by Hi and Lo being No_Uint. | |
3cce7f32 | 8331 | |
8332 | -- Note: we could do better here and in some cases switch back from | |
8333 | -- Bignum mode to normal mode, e.g. big mod 2 must be in the range | |
8334 | -- 0 .. 1, but the cases are rare and it is not worth the effort. | |
8335 | -- Failing to do this switching back is only an efficiency issue. | |
8336 | ||
f32c377d | 8337 | elsif Lo = No_Uint or else Lo < LLLo or else Hi > LLHi then |
3cce7f32 | 8338 | |
61016a7a | 8339 | -- OK, we are definitely outside the range of Long_Long_Integer. The |
f32c377d | 8340 | -- question is whether to move to Bignum mode, or stay in the domain |
61016a7a | 8341 | -- of Long_Long_Integer, signalling that an overflow check is needed. |
8342 | ||
8343 | -- Obviously in MINIMIZED mode we stay with LLI, since we are not in | |
8344 | -- the Bignum business. In ELIMINATED mode, we will normally move | |
8345 | -- into Bignum mode, but there is an exception if neither of our | |
8346 | -- operands is Bignum now, and we are at the top level (Top_Level | |
8347 | -- set True). In this case, there is no point in moving into Bignum | |
8348 | -- mode to prevent overflow if the caller will immediately convert | |
8349 | -- the Bignum value back to LLI with an overflow check. It's more | |
0df9d43f | 8350 | -- efficient to stay in LLI mode with an overflow check (if needed) |
61016a7a | 8351 | |
8352 | if Check_Mode = Minimized | |
8353 | or else (Top_Level and not Bignum_Operands) | |
8354 | then | |
0df9d43f | 8355 | if Do_Overflow_Check (N) then |
8356 | Enable_Overflow_Check (N); | |
8357 | end if; | |
3cce7f32 | 8358 | |
0df9d43f | 8359 | -- The result now has to be in Long_Long_Integer mode, so adjust |
8360 | -- the possible range to reflect this. Note these calls also | |
8361 | -- change No_Uint values from the top level case to LLI bounds. | |
61016a7a | 8362 | |
8363 | Max (Lo, LLLo); | |
8364 | Min (Hi, LLHi); | |
8365 | ||
8366 | -- Otherwise we are in ELIMINATED mode and we switch to Bignum mode | |
3cce7f32 | 8367 | |
8368 | else | |
8369 | pragma Assert (Check_Mode = Eliminated); | |
8370 | ||
8371 | declare | |
8372 | Fent : Entity_Id; | |
8373 | Args : List_Id; | |
8374 | ||
8375 | begin | |
8376 | case Nkind (N) is | |
8377 | when N_Op_Abs => | |
8378 | Fent := RTE (RE_Big_Abs); | |
8379 | ||
8380 | when N_Op_Add => | |
8381 | Fent := RTE (RE_Big_Add); | |
8382 | ||
8383 | when N_Op_Divide => | |
8384 | Fent := RTE (RE_Big_Div); | |
8385 | ||
8386 | when N_Op_Expon => | |
8387 | Fent := RTE (RE_Big_Exp); | |
8388 | ||
8389 | when N_Op_Minus => | |
8390 | Fent := RTE (RE_Big_Neg); | |
8391 | ||
8392 | when N_Op_Mod => | |
8393 | Fent := RTE (RE_Big_Mod); | |
8394 | ||
8395 | when N_Op_Multiply => | |
8396 | Fent := RTE (RE_Big_Mul); | |
8397 | ||
8398 | when N_Op_Rem => | |
8399 | Fent := RTE (RE_Big_Rem); | |
8400 | ||
8401 | when N_Op_Subtract => | |
8402 | Fent := RTE (RE_Big_Sub); | |
8403 | ||
8404 | -- Anything else is an internal error, this includes the | |
8405 | -- N_Op_Plus case, since how can plus cause the result | |
8406 | -- to be out of range if the operand is in range? | |
8407 | ||
8408 | when others => | |
8409 | raise Program_Error; | |
8410 | end case; | |
8411 | ||
8412 | -- Construct argument list for Bignum call, converting our | |
8413 | -- operands to Bignum form if they are not already there. | |
8414 | ||
8415 | Args := New_List; | |
8416 | ||
8417 | if Binary then | |
8418 | Append_To (Args, Convert_To_Bignum (Left_Opnd (N))); | |
8419 | end if; | |
8420 | ||
8421 | Append_To (Args, Convert_To_Bignum (Right_Opnd (N))); | |
8422 | ||
8423 | -- Now rewrite the arithmetic operator with a call to the | |
8424 | -- corresponding bignum function. | |
8425 | ||
8426 | Rewrite (N, | |
8427 | Make_Function_Call (Loc, | |
8428 | Name => New_Occurrence_Of (Fent, Loc), | |
8429 | Parameter_Associations => Args)); | |
0df9d43f | 8430 | Reanalyze (RTE (RE_Bignum), Suppress => True); |
61016a7a | 8431 | |
8432 | -- Indicate result is Bignum mode | |
8433 | ||
8434 | Lo := No_Uint; | |
8435 | Hi := No_Uint; | |
de922300 | 8436 | return; |
3cce7f32 | 8437 | end; |
8438 | end if; | |
8439 | ||
8440 | -- Otherwise we are in range of Long_Long_Integer, so no overflow | |
de922300 | 8441 | -- check is required, at least not yet. |
3cce7f32 | 8442 | |
8443 | else | |
de922300 | 8444 | Set_Do_Overflow_Check (N, False); |
8445 | end if; | |
3cce7f32 | 8446 | |
f32c377d | 8447 | -- Here we are not in Bignum territory, but we may have long long |
8448 | -- integer operands that need special handling. First a special check: | |
8449 | -- If an exponentiation operator exponent is of type Long_Long_Integer, | |
8450 | -- it means we converted it to prevent overflow, but exponentiation | |
8451 | -- requires a Natural right operand, so convert it back to Natural. | |
8452 | -- This conversion may raise an exception which is fine. | |
0326b4d4 | 8453 | |
f32c377d | 8454 | if Nkind (N) = N_Op_Expon and then Etype (Right_Opnd (N)) = LLIB then |
8455 | Convert_To_And_Rewrite (Standard_Natural, Right_Opnd (N)); | |
0326b4d4 | 8456 | end if; |
8457 | ||
de922300 | 8458 | -- Here we will do the operation in Long_Long_Integer. We do this even |
8459 | -- if we know an overflow check is required, better to do this in long | |
39a0c1d3 | 8460 | -- long integer mode, since we are less likely to overflow. |
3cce7f32 | 8461 | |
de922300 | 8462 | -- Convert right or only operand to Long_Long_Integer, except that |
8463 | -- we do not touch the exponentiation right operand. | |
3cce7f32 | 8464 | |
de922300 | 8465 | if Nkind (N) /= N_Op_Expon then |
8466 | Convert_To_And_Rewrite (LLIB, Right_Opnd (N)); | |
8467 | end if; | |
3cce7f32 | 8468 | |
de922300 | 8469 | -- Convert left operand to Long_Long_Integer for binary case |
49b3a812 | 8470 | |
de922300 | 8471 | if Binary then |
8472 | Convert_To_And_Rewrite (LLIB, Left_Opnd (N)); | |
8473 | end if; | |
8474 | ||
8475 | -- Reset node to unanalyzed | |
8476 | ||
8477 | Set_Analyzed (N, False); | |
8478 | Set_Etype (N, Empty); | |
8479 | Set_Entity (N, Empty); | |
8480 | ||
2fe22c69 | 8481 | -- Now analyze this new node. This reanalysis will complete processing |
8482 | -- for the node. In particular we will complete the expansion of an | |
8483 | -- exponentiation operator (e.g. changing A ** 2 to A * A), and also | |
8484 | -- we will complete any division checks (since we have not changed the | |
8485 | -- setting of the Do_Division_Check flag). | |
3cce7f32 | 8486 | |
0df9d43f | 8487 | -- We do this reanalysis in STRICT mode to avoid recursion into the |
39a0c1d3 | 8488 | -- MINIMIZED/ELIMINATED handling, since we are now done with that. |
3cce7f32 | 8489 | |
0df9d43f | 8490 | declare |
db415383 | 8491 | SG : constant Overflow_Mode_Type := |
8492 | Scope_Suppress.Overflow_Mode_General; | |
8493 | SA : constant Overflow_Mode_Type := | |
8494 | Scope_Suppress.Overflow_Mode_Assertions; | |
de922300 | 8495 | |
0df9d43f | 8496 | begin |
db415383 | 8497 | Scope_Suppress.Overflow_Mode_General := Strict; |
8498 | Scope_Suppress.Overflow_Mode_Assertions := Strict; | |
de922300 | 8499 | |
0df9d43f | 8500 | if not Do_Overflow_Check (N) then |
8501 | Reanalyze (LLIB, Suppress => True); | |
8502 | else | |
8503 | Reanalyze (LLIB); | |
8504 | end if; | |
8505 | ||
db415383 | 8506 | Scope_Suppress.Overflow_Mode_General := SG; |
8507 | Scope_Suppress.Overflow_Mode_Assertions := SA; | |
0df9d43f | 8508 | end; |
8509 | end Minimize_Eliminate_Overflows; | |
3cce7f32 | 8510 | |
8511 | ------------------------- | |
8512 | -- Overflow_Check_Mode -- | |
8513 | ------------------------- | |
8514 | ||
db415383 | 8515 | function Overflow_Check_Mode return Overflow_Mode_Type is |
ee6ba406 | 8516 | begin |
724d2bd8 | 8517 | if In_Assertion_Expr = 0 then |
db415383 | 8518 | return Scope_Suppress.Overflow_Mode_General; |
9dfe12ae | 8519 | else |
db415383 | 8520 | return Scope_Suppress.Overflow_Mode_Assertions; |
9dfe12ae | 8521 | end if; |
3cce7f32 | 8522 | end Overflow_Check_Mode; |
8523 | ||
8524 | -------------------------------- | |
8525 | -- Overflow_Checks_Suppressed -- | |
8526 | -------------------------------- | |
8527 | ||
8528 | function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is | |
8529 | begin | |
0df9d43f | 8530 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
8531 | return Is_Check_Suppressed (E, Overflow_Check); | |
8532 | else | |
8533 | return Scope_Suppress.Suppress (Overflow_Check); | |
8534 | end if; | |
ee6ba406 | 8535 | end Overflow_Checks_Suppressed; |
fc75802a | 8536 | |
37baba83 | 8537 | --------------------------------- |
8538 | -- Predicate_Checks_Suppressed -- | |
8539 | --------------------------------- | |
8540 | ||
8541 | function Predicate_Checks_Suppressed (E : Entity_Id) return Boolean is | |
8542 | begin | |
8543 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
8544 | return Is_Check_Suppressed (E, Predicate_Check); | |
8545 | else | |
8546 | return Scope_Suppress.Suppress (Predicate_Check); | |
8547 | end if; | |
8548 | end Predicate_Checks_Suppressed; | |
8549 | ||
ee6ba406 | 8550 | ----------------------------- |
8551 | -- Range_Checks_Suppressed -- | |
8552 | ----------------------------- | |
8553 | ||
8554 | function Range_Checks_Suppressed (E : Entity_Id) return Boolean is | |
8555 | begin | |
9dfe12ae | 8556 | if Present (E) then |
ce4d14c4 | 8557 | if Kill_Range_Checks (E) then |
9dfe12ae | 8558 | return True; |
5f46de53 | 8559 | |
9dfe12ae | 8560 | elsif Checks_May_Be_Suppressed (E) then |
8561 | return Is_Check_Suppressed (E, Range_Check); | |
8562 | end if; | |
8563 | end if; | |
ee6ba406 | 8564 | |
fafc6b97 | 8565 | return Scope_Suppress.Suppress (Range_Check); |
ee6ba406 | 8566 | end Range_Checks_Suppressed; |
8567 | ||
0577b0b1 | 8568 | ----------------------------------------- |
8569 | -- Range_Or_Validity_Checks_Suppressed -- | |
8570 | ----------------------------------------- | |
8571 | ||
8572 | -- Note: the coding would be simpler here if we simply made appropriate | |
8573 | -- calls to Range/Validity_Checks_Suppressed, but that would result in | |
8574 | -- duplicated checks which we prefer to avoid. | |
8575 | ||
8576 | function Range_Or_Validity_Checks_Suppressed | |
8577 | (Expr : Node_Id) return Boolean | |
8578 | is | |
8579 | begin | |
8580 | -- Immediate return if scope checks suppressed for either check | |
8581 | ||
fafc6b97 | 8582 | if Scope_Suppress.Suppress (Range_Check) |
8583 | or | |
8584 | Scope_Suppress.Suppress (Validity_Check) | |
8585 | then | |
0577b0b1 | 8586 | return True; |
8587 | end if; | |
8588 | ||
8589 | -- If no expression, that's odd, decide that checks are suppressed, | |
8590 | -- since we don't want anyone trying to do checks in this case, which | |
8591 | -- is most likely the result of some other error. | |
8592 | ||
8593 | if No (Expr) then | |
8594 | return True; | |
8595 | end if; | |
8596 | ||
8597 | -- Expression is present, so perform suppress checks on type | |
8598 | ||
8599 | declare | |
8600 | Typ : constant Entity_Id := Etype (Expr); | |
8601 | begin | |
ce4d14c4 | 8602 | if Checks_May_Be_Suppressed (Typ) |
0577b0b1 | 8603 | and then (Is_Check_Suppressed (Typ, Range_Check) |
8604 | or else | |
8605 | Is_Check_Suppressed (Typ, Validity_Check)) | |
8606 | then | |
8607 | return True; | |
8608 | end if; | |
8609 | end; | |
8610 | ||
8611 | -- If expression is an entity name, perform checks on this entity | |
8612 | ||
8613 | if Is_Entity_Name (Expr) then | |
8614 | declare | |
8615 | Ent : constant Entity_Id := Entity (Expr); | |
8616 | begin | |
8617 | if Checks_May_Be_Suppressed (Ent) then | |
8618 | return Is_Check_Suppressed (Ent, Range_Check) | |
8619 | or else Is_Check_Suppressed (Ent, Validity_Check); | |
8620 | end if; | |
8621 | end; | |
8622 | end if; | |
8623 | ||
8624 | -- If we fall through, no checks suppressed | |
8625 | ||
8626 | return False; | |
8627 | end Range_Or_Validity_Checks_Suppressed; | |
8628 | ||
226494a3 | 8629 | ------------------- |
8630 | -- Remove_Checks -- | |
8631 | ------------------- | |
8632 | ||
8633 | procedure Remove_Checks (Expr : Node_Id) is | |
226494a3 | 8634 | function Process (N : Node_Id) return Traverse_Result; |
8635 | -- Process a single node during the traversal | |
8636 | ||
8f6e4fd5 | 8637 | procedure Traverse is new Traverse_Proc (Process); |
8638 | -- The traversal procedure itself | |
226494a3 | 8639 | |
8640 | ------------- | |
8641 | -- Process -- | |
8642 | ------------- | |
8643 | ||
8644 | function Process (N : Node_Id) return Traverse_Result is | |
8645 | begin | |
8646 | if Nkind (N) not in N_Subexpr then | |
8647 | return Skip; | |
8648 | end if; | |
8649 | ||
8650 | Set_Do_Range_Check (N, False); | |
8651 | ||
8652 | case Nkind (N) is | |
8653 | when N_And_Then => | |
8f6e4fd5 | 8654 | Traverse (Left_Opnd (N)); |
226494a3 | 8655 | return Skip; |
8656 | ||
8657 | when N_Attribute_Reference => | |
226494a3 | 8658 | Set_Do_Overflow_Check (N, False); |
8659 | ||
226494a3 | 8660 | when N_Function_Call => |
8661 | Set_Do_Tag_Check (N, False); | |
8662 | ||
226494a3 | 8663 | when N_Op => |
8664 | Set_Do_Overflow_Check (N, False); | |
8665 | ||
8666 | case Nkind (N) is | |
8667 | when N_Op_Divide => | |
8668 | Set_Do_Division_Check (N, False); | |
8669 | ||
8670 | when N_Op_And => | |
8671 | Set_Do_Length_Check (N, False); | |
8672 | ||
8673 | when N_Op_Mod => | |
8674 | Set_Do_Division_Check (N, False); | |
8675 | ||
8676 | when N_Op_Or => | |
8677 | Set_Do_Length_Check (N, False); | |
8678 | ||
8679 | when N_Op_Rem => | |
8680 | Set_Do_Division_Check (N, False); | |
8681 | ||
8682 | when N_Op_Xor => | |
8683 | Set_Do_Length_Check (N, False); | |
8684 | ||
8685 | when others => | |
8686 | null; | |
8687 | end case; | |
8688 | ||
8689 | when N_Or_Else => | |
8f6e4fd5 | 8690 | Traverse (Left_Opnd (N)); |
226494a3 | 8691 | return Skip; |
8692 | ||
8693 | when N_Selected_Component => | |
226494a3 | 8694 | Set_Do_Discriminant_Check (N, False); |
8695 | ||
226494a3 | 8696 | when N_Type_Conversion => |
9dfe12ae | 8697 | Set_Do_Length_Check (N, False); |
8698 | Set_Do_Tag_Check (N, False); | |
226494a3 | 8699 | Set_Do_Overflow_Check (N, False); |
226494a3 | 8700 | |
8701 | when others => | |
8702 | null; | |
8703 | end case; | |
8704 | ||
8705 | return OK; | |
8706 | end Process; | |
8707 | ||
8708 | -- Start of processing for Remove_Checks | |
8709 | ||
8710 | begin | |
8f6e4fd5 | 8711 | Traverse (Expr); |
226494a3 | 8712 | end Remove_Checks; |
8713 | ||
ee6ba406 | 8714 | ---------------------------- |
8715 | -- Selected_Length_Checks -- | |
8716 | ---------------------------- | |
8717 | ||
8718 | function Selected_Length_Checks | |
8719 | (Ck_Node : Node_Id; | |
8720 | Target_Typ : Entity_Id; | |
8721 | Source_Typ : Entity_Id; | |
314a23b6 | 8722 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 8723 | is |
8724 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
8725 | S_Typ : Entity_Id; | |
8726 | T_Typ : Entity_Id; | |
8727 | Expr_Actual : Node_Id; | |
8728 | Exptyp : Entity_Id; | |
8729 | Cond : Node_Id := Empty; | |
8730 | Do_Access : Boolean := False; | |
8731 | Wnode : Node_Id := Warn_Node; | |
8732 | Ret_Result : Check_Result := (Empty, Empty); | |
8733 | Num_Checks : Natural := 0; | |
8734 | ||
8735 | procedure Add_Check (N : Node_Id); | |
8736 | -- Adds the action given to Ret_Result if N is non-Empty | |
8737 | ||
8738 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id; | |
8739 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id; | |
314a23b6 | 8740 | -- Comments required ??? |
ee6ba406 | 8741 | |
8742 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean; | |
8743 | -- True for equal literals and for nodes that denote the same constant | |
5f260d20 | 8744 | -- entity, even if its value is not a static constant. This includes the |
9dfe12ae | 8745 | -- case of a discriminal reference within an init proc. Removes some |
5f260d20 | 8746 | -- obviously superfluous checks. |
ee6ba406 | 8747 | |
8748 | function Length_E_Cond | |
8749 | (Exptyp : Entity_Id; | |
8750 | Typ : Entity_Id; | |
314a23b6 | 8751 | Indx : Nat) return Node_Id; |
ee6ba406 | 8752 | -- Returns expression to compute: |
8753 | -- Typ'Length /= Exptyp'Length | |
8754 | ||
8755 | function Length_N_Cond | |
8756 | (Expr : Node_Id; | |
8757 | Typ : Entity_Id; | |
314a23b6 | 8758 | Indx : Nat) return Node_Id; |
ee6ba406 | 8759 | -- Returns expression to compute: |
8760 | -- Typ'Length /= Expr'Length | |
8761 | ||
8762 | --------------- | |
8763 | -- Add_Check -- | |
8764 | --------------- | |
8765 | ||
8766 | procedure Add_Check (N : Node_Id) is | |
8767 | begin | |
8768 | if Present (N) then | |
8769 | ||
20cf157b | 8770 | -- For now, ignore attempt to place more than two checks ??? |
8771 | -- This is really worrisome, are we really discarding checks ??? | |
ee6ba406 | 8772 | |
8773 | if Num_Checks = 2 then | |
8774 | return; | |
8775 | end if; | |
8776 | ||
8777 | pragma Assert (Num_Checks <= 1); | |
8778 | Num_Checks := Num_Checks + 1; | |
8779 | Ret_Result (Num_Checks) := N; | |
8780 | end if; | |
8781 | end Add_Check; | |
8782 | ||
8783 | ------------------ | |
8784 | -- Get_E_Length -- | |
8785 | ------------------ | |
8786 | ||
8787 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is | |
00c403ee | 8788 | SE : constant Entity_Id := Scope (E); |
ee6ba406 | 8789 | N : Node_Id; |
8790 | E1 : Entity_Id := E; | |
ee6ba406 | 8791 | |
8792 | begin | |
8793 | if Ekind (Scope (E)) = E_Record_Type | |
8794 | and then Has_Discriminants (Scope (E)) | |
8795 | then | |
8796 | N := Build_Discriminal_Subtype_Of_Component (E); | |
8797 | ||
8798 | if Present (N) then | |
8799 | Insert_Action (Ck_Node, N); | |
8800 | E1 := Defining_Identifier (N); | |
8801 | end if; | |
8802 | end if; | |
8803 | ||
8804 | if Ekind (E1) = E_String_Literal_Subtype then | |
8805 | return | |
8806 | Make_Integer_Literal (Loc, | |
8807 | Intval => String_Literal_Length (E1)); | |
8808 | ||
00c403ee | 8809 | elsif SE /= Standard_Standard |
8810 | and then Ekind (Scope (SE)) = E_Protected_Type | |
8811 | and then Has_Discriminants (Scope (SE)) | |
8812 | and then Has_Completion (Scope (SE)) | |
ee6ba406 | 8813 | and then not Inside_Init_Proc |
8814 | then | |
ee6ba406 | 8815 | -- If the type whose length is needed is a private component |
8816 | -- constrained by a discriminant, we must expand the 'Length | |
8817 | -- attribute into an explicit computation, using the discriminal | |
8818 | -- of the current protected operation. This is because the actual | |
8819 | -- type of the prival is constructed after the protected opera- | |
8820 | -- tion has been fully expanded. | |
8821 | ||
8822 | declare | |
8823 | Indx_Type : Node_Id; | |
8824 | Lo : Node_Id; | |
8825 | Hi : Node_Id; | |
8826 | Do_Expand : Boolean := False; | |
8827 | ||
8828 | begin | |
8829 | Indx_Type := First_Index (E); | |
8830 | ||
8831 | for J in 1 .. Indx - 1 loop | |
8832 | Next_Index (Indx_Type); | |
8833 | end loop; | |
8834 | ||
2af58f67 | 8835 | Get_Index_Bounds (Indx_Type, Lo, Hi); |
ee6ba406 | 8836 | |
8837 | if Nkind (Lo) = N_Identifier | |
8838 | and then Ekind (Entity (Lo)) = E_In_Parameter | |
8839 | then | |
8840 | Lo := Get_Discriminal (E, Lo); | |
8841 | Do_Expand := True; | |
8842 | end if; | |
8843 | ||
8844 | if Nkind (Hi) = N_Identifier | |
8845 | and then Ekind (Entity (Hi)) = E_In_Parameter | |
8846 | then | |
8847 | Hi := Get_Discriminal (E, Hi); | |
8848 | Do_Expand := True; | |
8849 | end if; | |
8850 | ||
8851 | if Do_Expand then | |
8852 | if not Is_Entity_Name (Lo) then | |
9dfe12ae | 8853 | Lo := Duplicate_Subexpr_No_Checks (Lo); |
ee6ba406 | 8854 | end if; |
8855 | ||
8856 | if not Is_Entity_Name (Hi) then | |
9dfe12ae | 8857 | Lo := Duplicate_Subexpr_No_Checks (Hi); |
ee6ba406 | 8858 | end if; |
8859 | ||
8860 | N := | |
8861 | Make_Op_Add (Loc, | |
8862 | Left_Opnd => | |
8863 | Make_Op_Subtract (Loc, | |
8864 | Left_Opnd => Hi, | |
8865 | Right_Opnd => Lo), | |
8866 | ||
8867 | Right_Opnd => Make_Integer_Literal (Loc, 1)); | |
8868 | return N; | |
8869 | ||
8870 | else | |
8871 | N := | |
8872 | Make_Attribute_Reference (Loc, | |
8873 | Attribute_Name => Name_Length, | |
8874 | Prefix => | |
8875 | New_Occurrence_Of (E1, Loc)); | |
8876 | ||
8877 | if Indx > 1 then | |
8878 | Set_Expressions (N, New_List ( | |
8879 | Make_Integer_Literal (Loc, Indx))); | |
8880 | end if; | |
8881 | ||
8882 | return N; | |
8883 | end if; | |
8884 | end; | |
8885 | ||
8886 | else | |
8887 | N := | |
8888 | Make_Attribute_Reference (Loc, | |
8889 | Attribute_Name => Name_Length, | |
8890 | Prefix => | |
8891 | New_Occurrence_Of (E1, Loc)); | |
8892 | ||
8893 | if Indx > 1 then | |
8894 | Set_Expressions (N, New_List ( | |
8895 | Make_Integer_Literal (Loc, Indx))); | |
8896 | end if; | |
8897 | ||
8898 | return N; | |
ee6ba406 | 8899 | end if; |
8900 | end Get_E_Length; | |
8901 | ||
8902 | ------------------ | |
8903 | -- Get_N_Length -- | |
8904 | ------------------ | |
8905 | ||
8906 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is | |
8907 | begin | |
8908 | return | |
8909 | Make_Attribute_Reference (Loc, | |
8910 | Attribute_Name => Name_Length, | |
8911 | Prefix => | |
9dfe12ae | 8912 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 8913 | Expressions => New_List ( |
8914 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 8915 | end Get_N_Length; |
8916 | ||
8917 | ------------------- | |
8918 | -- Length_E_Cond -- | |
8919 | ------------------- | |
8920 | ||
8921 | function Length_E_Cond | |
8922 | (Exptyp : Entity_Id; | |
8923 | Typ : Entity_Id; | |
314a23b6 | 8924 | Indx : Nat) return Node_Id |
ee6ba406 | 8925 | is |
8926 | begin | |
8927 | return | |
8928 | Make_Op_Ne (Loc, | |
8929 | Left_Opnd => Get_E_Length (Typ, Indx), | |
8930 | Right_Opnd => Get_E_Length (Exptyp, Indx)); | |
ee6ba406 | 8931 | end Length_E_Cond; |
8932 | ||
8933 | ------------------- | |
8934 | -- Length_N_Cond -- | |
8935 | ------------------- | |
8936 | ||
8937 | function Length_N_Cond | |
8938 | (Expr : Node_Id; | |
8939 | Typ : Entity_Id; | |
314a23b6 | 8940 | Indx : Nat) return Node_Id |
ee6ba406 | 8941 | is |
8942 | begin | |
8943 | return | |
8944 | Make_Op_Ne (Loc, | |
8945 | Left_Opnd => Get_E_Length (Typ, Indx), | |
8946 | Right_Opnd => Get_N_Length (Expr, Indx)); | |
ee6ba406 | 8947 | end Length_N_Cond; |
8948 | ||
feff2f05 | 8949 | ----------------- |
8950 | -- Same_Bounds -- | |
8951 | ----------------- | |
8952 | ||
ee6ba406 | 8953 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is |
8954 | begin | |
8955 | return | |
8956 | (Nkind (L) = N_Integer_Literal | |
8957 | and then Nkind (R) = N_Integer_Literal | |
8958 | and then Intval (L) = Intval (R)) | |
8959 | ||
8960 | or else | |
8961 | (Is_Entity_Name (L) | |
8962 | and then Ekind (Entity (L)) = E_Constant | |
8963 | and then ((Is_Entity_Name (R) | |
8964 | and then Entity (L) = Entity (R)) | |
8965 | or else | |
8966 | (Nkind (R) = N_Type_Conversion | |
8967 | and then Is_Entity_Name (Expression (R)) | |
8968 | and then Entity (L) = Entity (Expression (R))))) | |
8969 | ||
8970 | or else | |
8971 | (Is_Entity_Name (R) | |
8972 | and then Ekind (Entity (R)) = E_Constant | |
8973 | and then Nkind (L) = N_Type_Conversion | |
8974 | and then Is_Entity_Name (Expression (L)) | |
5f260d20 | 8975 | and then Entity (R) = Entity (Expression (L))) |
8976 | ||
8977 | or else | |
8978 | (Is_Entity_Name (L) | |
8979 | and then Is_Entity_Name (R) | |
8980 | and then Entity (L) = Entity (R) | |
8981 | and then Ekind (Entity (L)) = E_In_Parameter | |
8982 | and then Inside_Init_Proc); | |
ee6ba406 | 8983 | end Same_Bounds; |
8984 | ||
8985 | -- Start of processing for Selected_Length_Checks | |
8986 | ||
8987 | begin | |
a33565dd | 8988 | if not Expander_Active then |
ee6ba406 | 8989 | return Ret_Result; |
8990 | end if; | |
8991 | ||
8992 | if Target_Typ = Any_Type | |
8993 | or else Target_Typ = Any_Composite | |
8994 | or else Raises_Constraint_Error (Ck_Node) | |
8995 | then | |
8996 | return Ret_Result; | |
8997 | end if; | |
8998 | ||
8999 | if No (Wnode) then | |
9000 | Wnode := Ck_Node; | |
9001 | end if; | |
9002 | ||
9003 | T_Typ := Target_Typ; | |
9004 | ||
9005 | if No (Source_Typ) then | |
9006 | S_Typ := Etype (Ck_Node); | |
9007 | else | |
9008 | S_Typ := Source_Typ; | |
9009 | end if; | |
9010 | ||
9011 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
9012 | return Ret_Result; | |
9013 | end if; | |
9014 | ||
9015 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
9016 | S_Typ := Designated_Type (S_Typ); | |
9017 | T_Typ := Designated_Type (T_Typ); | |
9018 | Do_Access := True; | |
9019 | ||
2af58f67 | 9020 | -- A simple optimization for the null case |
ee6ba406 | 9021 | |
2af58f67 | 9022 | if Known_Null (Ck_Node) then |
ee6ba406 | 9023 | return Ret_Result; |
9024 | end if; | |
9025 | end if; | |
9026 | ||
9027 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
9028 | if Is_Constrained (T_Typ) then | |
9029 | ||
92f1631f | 9030 | -- The checking code to be generated will freeze the corresponding |
9031 | -- array type. However, we must freeze the type now, so that the | |
9032 | -- freeze node does not appear within the generated if expression, | |
9033 | -- but ahead of it. | |
ee6ba406 | 9034 | |
9035 | Freeze_Before (Ck_Node, T_Typ); | |
9036 | ||
9037 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
84d0d4a5 | 9038 | Exptyp := Get_Actual_Subtype (Ck_Node); |
ee6ba406 | 9039 | |
9040 | if Is_Access_Type (Exptyp) then | |
9041 | Exptyp := Designated_Type (Exptyp); | |
9042 | end if; | |
9043 | ||
9044 | -- String_Literal case. This needs to be handled specially be- | |
9045 | -- cause no index types are available for string literals. The | |
9046 | -- condition is simply: | |
9047 | ||
9048 | -- T_Typ'Length = string-literal-length | |
9049 | ||
9dfe12ae | 9050 | if Nkind (Expr_Actual) = N_String_Literal |
9051 | and then Ekind (Etype (Expr_Actual)) = E_String_Literal_Subtype | |
9052 | then | |
ee6ba406 | 9053 | Cond := |
9054 | Make_Op_Ne (Loc, | |
9055 | Left_Opnd => Get_E_Length (T_Typ, 1), | |
9056 | Right_Opnd => | |
9057 | Make_Integer_Literal (Loc, | |
9058 | Intval => | |
9059 | String_Literal_Length (Etype (Expr_Actual)))); | |
9060 | ||
9061 | -- General array case. Here we have a usable actual subtype for | |
9062 | -- the expression, and the condition is built from the two types | |
9063 | -- (Do_Length): | |
9064 | ||
9065 | -- T_Typ'Length /= Exptyp'Length or else | |
9066 | -- T_Typ'Length (2) /= Exptyp'Length (2) or else | |
9067 | -- T_Typ'Length (3) /= Exptyp'Length (3) or else | |
9068 | -- ... | |
9069 | ||
9070 | elsif Is_Constrained (Exptyp) then | |
9071 | declare | |
9dfe12ae | 9072 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
9073 | ||
9074 | L_Index : Node_Id; | |
9075 | R_Index : Node_Id; | |
9076 | L_Low : Node_Id; | |
9077 | L_High : Node_Id; | |
9078 | R_Low : Node_Id; | |
9079 | R_High : Node_Id; | |
ee6ba406 | 9080 | L_Length : Uint; |
9081 | R_Length : Uint; | |
9dfe12ae | 9082 | Ref_Node : Node_Id; |
ee6ba406 | 9083 | |
9084 | begin | |
feff2f05 | 9085 | -- At the library level, we need to ensure that the type of |
9086 | -- the object is elaborated before the check itself is | |
9087 | -- emitted. This is only done if the object is in the | |
9088 | -- current compilation unit, otherwise the type is frozen | |
9089 | -- and elaborated in its unit. | |
9dfe12ae | 9090 | |
9091 | if Is_Itype (Exptyp) | |
9092 | and then | |
9093 | Ekind (Cunit_Entity (Current_Sem_Unit)) = E_Package | |
9094 | and then | |
9095 | not In_Package_Body (Cunit_Entity (Current_Sem_Unit)) | |
d66aa9f6 | 9096 | and then In_Open_Scopes (Scope (Exptyp)) |
9dfe12ae | 9097 | then |
9098 | Ref_Node := Make_Itype_Reference (Sloc (Ck_Node)); | |
9099 | Set_Itype (Ref_Node, Exptyp); | |
9100 | Insert_Action (Ck_Node, Ref_Node); | |
9101 | end if; | |
9102 | ||
ee6ba406 | 9103 | L_Index := First_Index (T_Typ); |
9104 | R_Index := First_Index (Exptyp); | |
9105 | ||
9106 | for Indx in 1 .. Ndims loop | |
9107 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 9108 | or else |
9109 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 9110 | then |
9111 | Get_Index_Bounds (L_Index, L_Low, L_High); | |
9112 | Get_Index_Bounds (R_Index, R_Low, R_High); | |
9113 | ||
9114 | -- Deal with compile time length check. Note that we | |
9115 | -- skip this in the access case, because the access | |
9116 | -- value may be null, so we cannot know statically. | |
9117 | ||
9118 | if not Do_Access | |
9119 | and then Compile_Time_Known_Value (L_Low) | |
9120 | and then Compile_Time_Known_Value (L_High) | |
9121 | and then Compile_Time_Known_Value (R_Low) | |
9122 | and then Compile_Time_Known_Value (R_High) | |
9123 | then | |
9124 | if Expr_Value (L_High) >= Expr_Value (L_Low) then | |
9125 | L_Length := Expr_Value (L_High) - | |
9126 | Expr_Value (L_Low) + 1; | |
9127 | else | |
9128 | L_Length := UI_From_Int (0); | |
9129 | end if; | |
9130 | ||
9131 | if Expr_Value (R_High) >= Expr_Value (R_Low) then | |
9132 | R_Length := Expr_Value (R_High) - | |
9133 | Expr_Value (R_Low) + 1; | |
9134 | else | |
9135 | R_Length := UI_From_Int (0); | |
9136 | end if; | |
9137 | ||
9138 | if L_Length > R_Length then | |
9139 | Add_Check | |
9140 | (Compile_Time_Constraint_Error | |
cb97ae5c | 9141 | (Wnode, "too few elements for}??", T_Typ)); |
ee6ba406 | 9142 | |
9143 | elsif L_Length < R_Length then | |
9144 | Add_Check | |
9145 | (Compile_Time_Constraint_Error | |
cb97ae5c | 9146 | (Wnode, "too many elements for}??", T_Typ)); |
ee6ba406 | 9147 | end if; |
9148 | ||
9149 | -- The comparison for an individual index subtype | |
9150 | -- is omitted if the corresponding index subtypes | |
9151 | -- statically match, since the result is known to | |
9152 | -- be true. Note that this test is worth while even | |
9153 | -- though we do static evaluation, because non-static | |
9154 | -- subtypes can statically match. | |
9155 | ||
9156 | elsif not | |
9157 | Subtypes_Statically_Match | |
9158 | (Etype (L_Index), Etype (R_Index)) | |
9159 | ||
9160 | and then not | |
9161 | (Same_Bounds (L_Low, R_Low) | |
9162 | and then Same_Bounds (L_High, R_High)) | |
9163 | then | |
9164 | Evolve_Or_Else | |
9165 | (Cond, Length_E_Cond (Exptyp, T_Typ, Indx)); | |
9166 | end if; | |
9167 | ||
9168 | Next (L_Index); | |
9169 | Next (R_Index); | |
9170 | end if; | |
9171 | end loop; | |
9172 | end; | |
9173 | ||
9174 | -- Handle cases where we do not get a usable actual subtype that | |
9175 | -- is constrained. This happens for example in the function call | |
9176 | -- and explicit dereference cases. In these cases, we have to get | |
9177 | -- the length or range from the expression itself, making sure we | |
9178 | -- do not evaluate it more than once. | |
9179 | ||
9180 | -- Here Ck_Node is the original expression, or more properly the | |
feff2f05 | 9181 | -- result of applying Duplicate_Expr to the original tree, forcing |
9182 | -- the result to be a name. | |
ee6ba406 | 9183 | |
9184 | else | |
9185 | declare | |
9dfe12ae | 9186 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 9187 | |
9188 | begin | |
9189 | -- Build the condition for the explicit dereference case | |
9190 | ||
9191 | for Indx in 1 .. Ndims loop | |
9192 | Evolve_Or_Else | |
9193 | (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx)); | |
9194 | end loop; | |
9195 | end; | |
9196 | end if; | |
9197 | end if; | |
9198 | end if; | |
9199 | ||
9200 | -- Construct the test and insert into the tree | |
9201 | ||
9202 | if Present (Cond) then | |
9203 | if Do_Access then | |
9204 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
9205 | end if; | |
9206 | ||
f15731c4 | 9207 | Add_Check |
9208 | (Make_Raise_Constraint_Error (Loc, | |
9209 | Condition => Cond, | |
9210 | Reason => CE_Length_Check_Failed)); | |
ee6ba406 | 9211 | end if; |
9212 | ||
9213 | return Ret_Result; | |
ee6ba406 | 9214 | end Selected_Length_Checks; |
9215 | ||
9216 | --------------------------- | |
9217 | -- Selected_Range_Checks -- | |
9218 | --------------------------- | |
9219 | ||
9220 | function Selected_Range_Checks | |
9221 | (Ck_Node : Node_Id; | |
9222 | Target_Typ : Entity_Id; | |
9223 | Source_Typ : Entity_Id; | |
314a23b6 | 9224 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 9225 | is |
9226 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
9227 | S_Typ : Entity_Id; | |
9228 | T_Typ : Entity_Id; | |
9229 | Expr_Actual : Node_Id; | |
9230 | Exptyp : Entity_Id; | |
9231 | Cond : Node_Id := Empty; | |
9232 | Do_Access : Boolean := False; | |
9233 | Wnode : Node_Id := Warn_Node; | |
9234 | Ret_Result : Check_Result := (Empty, Empty); | |
9235 | Num_Checks : Integer := 0; | |
9236 | ||
9237 | procedure Add_Check (N : Node_Id); | |
9238 | -- Adds the action given to Ret_Result if N is non-Empty | |
9239 | ||
9240 | function Discrete_Range_Cond | |
9241 | (Expr : Node_Id; | |
314a23b6 | 9242 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 9243 | -- Returns expression to compute: |
9244 | -- Low_Bound (Expr) < Typ'First | |
9245 | -- or else | |
9246 | -- High_Bound (Expr) > Typ'Last | |
9247 | ||
9248 | function Discrete_Expr_Cond | |
9249 | (Expr : Node_Id; | |
314a23b6 | 9250 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 9251 | -- Returns expression to compute: |
9252 | -- Expr < Typ'First | |
9253 | -- or else | |
9254 | -- Expr > Typ'Last | |
9255 | ||
9256 | function Get_E_First_Or_Last | |
3cb12758 | 9257 | (Loc : Source_Ptr; |
9258 | E : Entity_Id; | |
ee6ba406 | 9259 | Indx : Nat; |
314a23b6 | 9260 | Nam : Name_Id) return Node_Id; |
79212397 | 9261 | -- Returns an attribute reference |
ee6ba406 | 9262 | -- E'First or E'Last |
79212397 | 9263 | -- with a source location of Loc. |
f73ee678 | 9264 | -- |
79212397 | 9265 | -- Nam is Name_First or Name_Last, according to which attribute is |
9266 | -- desired. If Indx is non-zero, it is passed as a literal in the | |
9267 | -- Expressions of the attribute reference (identifying the desired | |
9268 | -- array dimension). | |
ee6ba406 | 9269 | |
9270 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id; | |
9271 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id; | |
9272 | -- Returns expression to compute: | |
9dfe12ae | 9273 | -- N'First or N'Last using Duplicate_Subexpr_No_Checks |
ee6ba406 | 9274 | |
9275 | function Range_E_Cond | |
9276 | (Exptyp : Entity_Id; | |
9277 | Typ : Entity_Id; | |
9278 | Indx : Nat) | |
9279 | return Node_Id; | |
9280 | -- Returns expression to compute: | |
9281 | -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last | |
9282 | ||
9283 | function Range_Equal_E_Cond | |
9284 | (Exptyp : Entity_Id; | |
9285 | Typ : Entity_Id; | |
314a23b6 | 9286 | Indx : Nat) return Node_Id; |
ee6ba406 | 9287 | -- Returns expression to compute: |
9288 | -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last | |
9289 | ||
9290 | function Range_N_Cond | |
9291 | (Expr : Node_Id; | |
9292 | Typ : Entity_Id; | |
314a23b6 | 9293 | Indx : Nat) return Node_Id; |
ee6ba406 | 9294 | -- Return expression to compute: |
9295 | -- Expr'First < Typ'First or else Expr'Last > Typ'Last | |
9296 | ||
9297 | --------------- | |
9298 | -- Add_Check -- | |
9299 | --------------- | |
9300 | ||
9301 | procedure Add_Check (N : Node_Id) is | |
9302 | begin | |
9303 | if Present (N) then | |
9304 | ||
9305 | -- For now, ignore attempt to place more than 2 checks ??? | |
9306 | ||
9307 | if Num_Checks = 2 then | |
9308 | return; | |
9309 | end if; | |
9310 | ||
9311 | pragma Assert (Num_Checks <= 1); | |
9312 | Num_Checks := Num_Checks + 1; | |
9313 | Ret_Result (Num_Checks) := N; | |
9314 | end if; | |
9315 | end Add_Check; | |
9316 | ||
9317 | ------------------------- | |
9318 | -- Discrete_Expr_Cond -- | |
9319 | ------------------------- | |
9320 | ||
9321 | function Discrete_Expr_Cond | |
9322 | (Expr : Node_Id; | |
314a23b6 | 9323 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 9324 | is |
9325 | begin | |
9326 | return | |
9327 | Make_Or_Else (Loc, | |
9328 | Left_Opnd => | |
9329 | Make_Op_Lt (Loc, | |
9330 | Left_Opnd => | |
9dfe12ae | 9331 | Convert_To (Base_Type (Typ), |
9332 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 9333 | Right_Opnd => |
9334 | Convert_To (Base_Type (Typ), | |
3cb12758 | 9335 | Get_E_First_Or_Last (Loc, Typ, 0, Name_First))), |
ee6ba406 | 9336 | |
9337 | Right_Opnd => | |
9338 | Make_Op_Gt (Loc, | |
9339 | Left_Opnd => | |
9dfe12ae | 9340 | Convert_To (Base_Type (Typ), |
9341 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 9342 | Right_Opnd => |
9343 | Convert_To | |
9344 | (Base_Type (Typ), | |
3cb12758 | 9345 | Get_E_First_Or_Last (Loc, Typ, 0, Name_Last)))); |
ee6ba406 | 9346 | end Discrete_Expr_Cond; |
9347 | ||
9348 | ------------------------- | |
9349 | -- Discrete_Range_Cond -- | |
9350 | ------------------------- | |
9351 | ||
9352 | function Discrete_Range_Cond | |
9353 | (Expr : Node_Id; | |
314a23b6 | 9354 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 9355 | is |
9356 | LB : Node_Id := Low_Bound (Expr); | |
9357 | HB : Node_Id := High_Bound (Expr); | |
9358 | ||
9359 | Left_Opnd : Node_Id; | |
9360 | Right_Opnd : Node_Id; | |
9361 | ||
9362 | begin | |
9363 | if Nkind (LB) = N_Identifier | |
feff2f05 | 9364 | and then Ekind (Entity (LB)) = E_Discriminant |
9365 | then | |
ee6ba406 | 9366 | LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc); |
9367 | end if; | |
9368 | ||
ee6ba406 | 9369 | Left_Opnd := |
9370 | Make_Op_Lt (Loc, | |
9371 | Left_Opnd => | |
9372 | Convert_To | |
9dfe12ae | 9373 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (LB)), |
ee6ba406 | 9374 | |
9375 | Right_Opnd => | |
9376 | Convert_To | |
3cb12758 | 9377 | (Base_Type (Typ), |
9378 | Get_E_First_Or_Last (Loc, Typ, 0, Name_First))); | |
ee6ba406 | 9379 | |
ba9b1a39 | 9380 | if Nkind (HB) = N_Identifier |
9381 | and then Ekind (Entity (HB)) = E_Discriminant | |
ee6ba406 | 9382 | then |
ba9b1a39 | 9383 | HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc); |
ee6ba406 | 9384 | end if; |
9385 | ||
9386 | Right_Opnd := | |
9387 | Make_Op_Gt (Loc, | |
9388 | Left_Opnd => | |
9389 | Convert_To | |
9dfe12ae | 9390 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (HB)), |
ee6ba406 | 9391 | |
9392 | Right_Opnd => | |
9393 | Convert_To | |
9394 | (Base_Type (Typ), | |
3cb12758 | 9395 | Get_E_First_Or_Last (Loc, Typ, 0, Name_Last))); |
ee6ba406 | 9396 | |
9397 | return Make_Or_Else (Loc, Left_Opnd, Right_Opnd); | |
9398 | end Discrete_Range_Cond; | |
9399 | ||
9400 | ------------------------- | |
9401 | -- Get_E_First_Or_Last -- | |
9402 | ------------------------- | |
9403 | ||
9404 | function Get_E_First_Or_Last | |
3cb12758 | 9405 | (Loc : Source_Ptr; |
9406 | E : Entity_Id; | |
ee6ba406 | 9407 | Indx : Nat; |
314a23b6 | 9408 | Nam : Name_Id) return Node_Id |
ee6ba406 | 9409 | is |
3cb12758 | 9410 | Exprs : List_Id; |
ee6ba406 | 9411 | begin |
3cb12758 | 9412 | if Indx > 0 then |
9413 | Exprs := New_List (Make_Integer_Literal (Loc, UI_From_Int (Indx))); | |
ee6ba406 | 9414 | else |
3cb12758 | 9415 | Exprs := No_List; |
ee6ba406 | 9416 | end if; |
9417 | ||
3cb12758 | 9418 | return Make_Attribute_Reference (Loc, |
9419 | Prefix => New_Occurrence_Of (E, Loc), | |
9420 | Attribute_Name => Nam, | |
9421 | Expressions => Exprs); | |
ee6ba406 | 9422 | end Get_E_First_Or_Last; |
9423 | ||
9424 | ----------------- | |
9425 | -- Get_N_First -- | |
9426 | ----------------- | |
9427 | ||
9428 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is | |
9429 | begin | |
9430 | return | |
9431 | Make_Attribute_Reference (Loc, | |
9432 | Attribute_Name => Name_First, | |
9433 | Prefix => | |
9dfe12ae | 9434 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 9435 | Expressions => New_List ( |
9436 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 9437 | end Get_N_First; |
9438 | ||
9439 | ---------------- | |
9440 | -- Get_N_Last -- | |
9441 | ---------------- | |
9442 | ||
9443 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is | |
9444 | begin | |
9445 | return | |
9446 | Make_Attribute_Reference (Loc, | |
9447 | Attribute_Name => Name_Last, | |
9448 | Prefix => | |
9dfe12ae | 9449 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 9450 | Expressions => New_List ( |
9451 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 9452 | end Get_N_Last; |
9453 | ||
9454 | ------------------ | |
9455 | -- Range_E_Cond -- | |
9456 | ------------------ | |
9457 | ||
9458 | function Range_E_Cond | |
9459 | (Exptyp : Entity_Id; | |
9460 | Typ : Entity_Id; | |
314a23b6 | 9461 | Indx : Nat) return Node_Id |
ee6ba406 | 9462 | is |
9463 | begin | |
9464 | return | |
9465 | Make_Or_Else (Loc, | |
9466 | Left_Opnd => | |
9467 | Make_Op_Lt (Loc, | |
3cb12758 | 9468 | Left_Opnd => |
9469 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First), | |
9470 | Right_Opnd => | |
9471 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
ee6ba406 | 9472 | |
9473 | Right_Opnd => | |
9474 | Make_Op_Gt (Loc, | |
3cb12758 | 9475 | Left_Opnd => |
9476 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last), | |
9477 | Right_Opnd => | |
9478 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 9479 | end Range_E_Cond; |
9480 | ||
9481 | ------------------------ | |
9482 | -- Range_Equal_E_Cond -- | |
9483 | ------------------------ | |
9484 | ||
9485 | function Range_Equal_E_Cond | |
9486 | (Exptyp : Entity_Id; | |
9487 | Typ : Entity_Id; | |
314a23b6 | 9488 | Indx : Nat) return Node_Id |
ee6ba406 | 9489 | is |
9490 | begin | |
9491 | return | |
9492 | Make_Or_Else (Loc, | |
9493 | Left_Opnd => | |
9494 | Make_Op_Ne (Loc, | |
3cb12758 | 9495 | Left_Opnd => |
9496 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First), | |
9497 | Right_Opnd => | |
9498 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
9499 | ||
ee6ba406 | 9500 | Right_Opnd => |
9501 | Make_Op_Ne (Loc, | |
3cb12758 | 9502 | Left_Opnd => |
9503 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last), | |
9504 | Right_Opnd => | |
9505 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 9506 | end Range_Equal_E_Cond; |
9507 | ||
9508 | ------------------ | |
9509 | -- Range_N_Cond -- | |
9510 | ------------------ | |
9511 | ||
9512 | function Range_N_Cond | |
9513 | (Expr : Node_Id; | |
9514 | Typ : Entity_Id; | |
314a23b6 | 9515 | Indx : Nat) return Node_Id |
ee6ba406 | 9516 | is |
9517 | begin | |
9518 | return | |
9519 | Make_Or_Else (Loc, | |
9520 | Left_Opnd => | |
9521 | Make_Op_Lt (Loc, | |
3cb12758 | 9522 | Left_Opnd => |
9523 | Get_N_First (Expr, Indx), | |
9524 | Right_Opnd => | |
9525 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
ee6ba406 | 9526 | |
9527 | Right_Opnd => | |
9528 | Make_Op_Gt (Loc, | |
3cb12758 | 9529 | Left_Opnd => |
9530 | Get_N_Last (Expr, Indx), | |
9531 | Right_Opnd => | |
9532 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 9533 | end Range_N_Cond; |
9534 | ||
9535 | -- Start of processing for Selected_Range_Checks | |
9536 | ||
9537 | begin | |
a33565dd | 9538 | if not Expander_Active then |
ee6ba406 | 9539 | return Ret_Result; |
9540 | end if; | |
9541 | ||
9542 | if Target_Typ = Any_Type | |
9543 | or else Target_Typ = Any_Composite | |
9544 | or else Raises_Constraint_Error (Ck_Node) | |
9545 | then | |
9546 | return Ret_Result; | |
9547 | end if; | |
9548 | ||
9549 | if No (Wnode) then | |
9550 | Wnode := Ck_Node; | |
9551 | end if; | |
9552 | ||
9553 | T_Typ := Target_Typ; | |
9554 | ||
9555 | if No (Source_Typ) then | |
9556 | S_Typ := Etype (Ck_Node); | |
9557 | else | |
9558 | S_Typ := Source_Typ; | |
9559 | end if; | |
9560 | ||
9561 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
9562 | return Ret_Result; | |
9563 | end if; | |
9564 | ||
9565 | -- The order of evaluating T_Typ before S_Typ seems to be critical | |
9566 | -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed | |
9567 | -- in, and since Node can be an N_Range node, it might be invalid. | |
9568 | -- Should there be an assert check somewhere for taking the Etype of | |
9569 | -- an N_Range node ??? | |
9570 | ||
9571 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
9572 | S_Typ := Designated_Type (S_Typ); | |
9573 | T_Typ := Designated_Type (T_Typ); | |
9574 | Do_Access := True; | |
9575 | ||
2af58f67 | 9576 | -- A simple optimization for the null case |
ee6ba406 | 9577 | |
2af58f67 | 9578 | if Known_Null (Ck_Node) then |
ee6ba406 | 9579 | return Ret_Result; |
9580 | end if; | |
9581 | end if; | |
9582 | ||
9583 | -- For an N_Range Node, check for a null range and then if not | |
9584 | -- null generate a range check action. | |
9585 | ||
9586 | if Nkind (Ck_Node) = N_Range then | |
9587 | ||
9588 | -- There's no point in checking a range against itself | |
9589 | ||
9590 | if Ck_Node = Scalar_Range (T_Typ) then | |
9591 | return Ret_Result; | |
9592 | end if; | |
9593 | ||
9594 | declare | |
9595 | T_LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
9596 | T_HB : constant Node_Id := Type_High_Bound (T_Typ); | |
eefa141b | 9597 | Known_T_LB : constant Boolean := Compile_Time_Known_Value (T_LB); |
9598 | Known_T_HB : constant Boolean := Compile_Time_Known_Value (T_HB); | |
ee6ba406 | 9599 | |
eefa141b | 9600 | LB : Node_Id := Low_Bound (Ck_Node); |
9601 | HB : Node_Id := High_Bound (Ck_Node); | |
9602 | Known_LB : Boolean; | |
9603 | Known_HB : Boolean; | |
9604 | ||
9605 | Null_Range : Boolean; | |
ee6ba406 | 9606 | Out_Of_Range_L : Boolean; |
9607 | Out_Of_Range_H : Boolean; | |
9608 | ||
9609 | begin | |
eefa141b | 9610 | -- Compute what is known at compile time |
9611 | ||
9612 | if Known_T_LB and Known_T_HB then | |
9613 | if Compile_Time_Known_Value (LB) then | |
9614 | Known_LB := True; | |
9615 | ||
9616 | -- There's no point in checking that a bound is within its | |
9617 | -- own range so pretend that it is known in this case. First | |
9618 | -- deal with low bound. | |
9619 | ||
9620 | elsif Ekind (Etype (LB)) = E_Signed_Integer_Subtype | |
9621 | and then Scalar_Range (Etype (LB)) = Scalar_Range (T_Typ) | |
9622 | then | |
9623 | LB := T_LB; | |
9624 | Known_LB := True; | |
9625 | ||
9626 | else | |
9627 | Known_LB := False; | |
9628 | end if; | |
9629 | ||
9630 | -- Likewise for the high bound | |
9631 | ||
9632 | if Compile_Time_Known_Value (HB) then | |
9633 | Known_HB := True; | |
9634 | ||
9635 | elsif Ekind (Etype (HB)) = E_Signed_Integer_Subtype | |
9636 | and then Scalar_Range (Etype (HB)) = Scalar_Range (T_Typ) | |
9637 | then | |
9638 | HB := T_HB; | |
9639 | Known_HB := True; | |
eefa141b | 9640 | else |
9641 | Known_HB := False; | |
9642 | end if; | |
9643 | end if; | |
9644 | ||
9645 | -- Check for case where everything is static and we can do the | |
9646 | -- check at compile time. This is skipped if we have an access | |
9647 | -- type, since the access value may be null. | |
9648 | ||
9649 | -- ??? This code can be improved since you only need to know that | |
9650 | -- the two respective bounds (LB & T_LB or HB & T_HB) are known at | |
9651 | -- compile time to emit pertinent messages. | |
9652 | ||
9653 | if Known_T_LB and Known_T_HB and Known_LB and Known_HB | |
9654 | and not Do_Access | |
ee6ba406 | 9655 | then |
9656 | -- Floating-point case | |
9657 | ||
9658 | if Is_Floating_Point_Type (S_Typ) then | |
9659 | Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB); | |
9660 | Out_Of_Range_L := | |
9661 | (Expr_Value_R (LB) < Expr_Value_R (T_LB)) | |
eefa141b | 9662 | or else |
ee6ba406 | 9663 | (Expr_Value_R (LB) > Expr_Value_R (T_HB)); |
9664 | ||
9665 | Out_Of_Range_H := | |
9666 | (Expr_Value_R (HB) > Expr_Value_R (T_HB)) | |
eefa141b | 9667 | or else |
ee6ba406 | 9668 | (Expr_Value_R (HB) < Expr_Value_R (T_LB)); |
9669 | ||
9670 | -- Fixed or discrete type case | |
9671 | ||
9672 | else | |
9673 | Null_Range := Expr_Value (HB) < Expr_Value (LB); | |
9674 | Out_Of_Range_L := | |
9675 | (Expr_Value (LB) < Expr_Value (T_LB)) | |
eefa141b | 9676 | or else |
ee6ba406 | 9677 | (Expr_Value (LB) > Expr_Value (T_HB)); |
9678 | ||
9679 | Out_Of_Range_H := | |
9680 | (Expr_Value (HB) > Expr_Value (T_HB)) | |
eefa141b | 9681 | or else |
ee6ba406 | 9682 | (Expr_Value (HB) < Expr_Value (T_LB)); |
9683 | end if; | |
9684 | ||
9685 | if not Null_Range then | |
9686 | if Out_Of_Range_L then | |
9687 | if No (Warn_Node) then | |
9688 | Add_Check | |
9689 | (Compile_Time_Constraint_Error | |
9690 | (Low_Bound (Ck_Node), | |
cb97ae5c | 9691 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 9692 | |
9693 | else | |
9694 | Add_Check | |
9695 | (Compile_Time_Constraint_Error | |
9696 | (Wnode, | |
cb97ae5c | 9697 | "static range out of bounds of}??", T_Typ)); |
ee6ba406 | 9698 | end if; |
9699 | end if; | |
9700 | ||
9701 | if Out_Of_Range_H then | |
9702 | if No (Warn_Node) then | |
9703 | Add_Check | |
9704 | (Compile_Time_Constraint_Error | |
9705 | (High_Bound (Ck_Node), | |
cb97ae5c | 9706 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 9707 | |
9708 | else | |
9709 | Add_Check | |
9710 | (Compile_Time_Constraint_Error | |
9711 | (Wnode, | |
cb97ae5c | 9712 | "static range out of bounds of}??", T_Typ)); |
ee6ba406 | 9713 | end if; |
9714 | end if; | |
ee6ba406 | 9715 | end if; |
9716 | ||
9717 | else | |
9718 | declare | |
9719 | LB : Node_Id := Low_Bound (Ck_Node); | |
9720 | HB : Node_Id := High_Bound (Ck_Node); | |
9721 | ||
9722 | begin | |
feff2f05 | 9723 | -- If either bound is a discriminant and we are within the |
9724 | -- record declaration, it is a use of the discriminant in a | |
9725 | -- constraint of a component, and nothing can be checked | |
9726 | -- here. The check will be emitted within the init proc. | |
9727 | -- Before then, the discriminal has no real meaning. | |
9728 | -- Similarly, if the entity is a discriminal, there is no | |
9729 | -- check to perform yet. | |
9730 | ||
9731 | -- The same holds within a discriminated synchronized type, | |
9732 | -- where the discriminant may constrain a component or an | |
9733 | -- entry family. | |
ee6ba406 | 9734 | |
9735 | if Nkind (LB) = N_Identifier | |
0577b0b1 | 9736 | and then Denotes_Discriminant (LB, True) |
ee6ba406 | 9737 | then |
0577b0b1 | 9738 | if Current_Scope = Scope (Entity (LB)) |
9739 | or else Is_Concurrent_Type (Current_Scope) | |
9740 | or else Ekind (Entity (LB)) /= E_Discriminant | |
9741 | then | |
ee6ba406 | 9742 | return Ret_Result; |
9743 | else | |
9744 | LB := | |
9745 | New_Occurrence_Of (Discriminal (Entity (LB)), Loc); | |
9746 | end if; | |
9747 | end if; | |
9748 | ||
9749 | if Nkind (HB) = N_Identifier | |
0577b0b1 | 9750 | and then Denotes_Discriminant (HB, True) |
ee6ba406 | 9751 | then |
0577b0b1 | 9752 | if Current_Scope = Scope (Entity (HB)) |
9753 | or else Is_Concurrent_Type (Current_Scope) | |
9754 | or else Ekind (Entity (HB)) /= E_Discriminant | |
9755 | then | |
ee6ba406 | 9756 | return Ret_Result; |
9757 | else | |
9758 | HB := | |
9759 | New_Occurrence_Of (Discriminal (Entity (HB)), Loc); | |
9760 | end if; | |
9761 | end if; | |
9762 | ||
9763 | Cond := Discrete_Range_Cond (Ck_Node, T_Typ); | |
9764 | Set_Paren_Count (Cond, 1); | |
9765 | ||
9766 | Cond := | |
9767 | Make_And_Then (Loc, | |
9768 | Left_Opnd => | |
9769 | Make_Op_Ge (Loc, | |
86d32751 | 9770 | Left_Opnd => |
9771 | Convert_To (Base_Type (Etype (HB)), | |
9772 | Duplicate_Subexpr_No_Checks (HB)), | |
9773 | Right_Opnd => | |
9774 | Convert_To (Base_Type (Etype (LB)), | |
9775 | Duplicate_Subexpr_No_Checks (LB))), | |
ee6ba406 | 9776 | Right_Opnd => Cond); |
9777 | end; | |
ee6ba406 | 9778 | end if; |
9779 | end; | |
9780 | ||
9781 | elsif Is_Scalar_Type (S_Typ) then | |
9782 | ||
9783 | -- This somewhat duplicates what Apply_Scalar_Range_Check does, | |
9784 | -- except the above simply sets a flag in the node and lets | |
9785 | -- gigi generate the check base on the Etype of the expression. | |
9786 | -- Sometimes, however we want to do a dynamic check against an | |
9787 | -- arbitrary target type, so we do that here. | |
9788 | ||
9789 | if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then | |
9790 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
9791 | ||
9792 | -- For literals, we can tell if the constraint error will be | |
9793 | -- raised at compile time, so we never need a dynamic check, but | |
9794 | -- if the exception will be raised, then post the usual warning, | |
9795 | -- and replace the literal with a raise constraint error | |
9796 | -- expression. As usual, skip this for access types | |
9797 | ||
20cf157b | 9798 | elsif Compile_Time_Known_Value (Ck_Node) and then not Do_Access then |
ee6ba406 | 9799 | declare |
9800 | LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
9801 | UB : constant Node_Id := Type_High_Bound (T_Typ); | |
9802 | ||
9803 | Out_Of_Range : Boolean; | |
9804 | Static_Bounds : constant Boolean := | |
b6341c67 | 9805 | Compile_Time_Known_Value (LB) |
9806 | and Compile_Time_Known_Value (UB); | |
ee6ba406 | 9807 | |
9808 | begin | |
9809 | -- Following range tests should use Sem_Eval routine ??? | |
9810 | ||
9811 | if Static_Bounds then | |
9812 | if Is_Floating_Point_Type (S_Typ) then | |
9813 | Out_Of_Range := | |
9814 | (Expr_Value_R (Ck_Node) < Expr_Value_R (LB)) | |
9815 | or else | |
9816 | (Expr_Value_R (Ck_Node) > Expr_Value_R (UB)); | |
9817 | ||
eefa141b | 9818 | -- Fixed or discrete type |
9819 | ||
9820 | else | |
ee6ba406 | 9821 | Out_Of_Range := |
9822 | Expr_Value (Ck_Node) < Expr_Value (LB) | |
9823 | or else | |
9824 | Expr_Value (Ck_Node) > Expr_Value (UB); | |
9825 | end if; | |
9826 | ||
eefa141b | 9827 | -- Bounds of the type are static and the literal is out of |
9828 | -- range so output a warning message. | |
ee6ba406 | 9829 | |
9830 | if Out_Of_Range then | |
9831 | if No (Warn_Node) then | |
9832 | Add_Check | |
9833 | (Compile_Time_Constraint_Error | |
9834 | (Ck_Node, | |
cb97ae5c | 9835 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 9836 | |
9837 | else | |
9838 | Add_Check | |
9839 | (Compile_Time_Constraint_Error | |
9840 | (Wnode, | |
cb97ae5c | 9841 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 9842 | end if; |
9843 | end if; | |
9844 | ||
9845 | else | |
9846 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
9847 | end if; | |
9848 | end; | |
9849 | ||
9850 | -- Here for the case of a non-static expression, we need a runtime | |
9851 | -- check unless the source type range is guaranteed to be in the | |
9852 | -- range of the target type. | |
9853 | ||
9854 | else | |
7a1dabb3 | 9855 | if not In_Subrange_Of (S_Typ, T_Typ) then |
ee6ba406 | 9856 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); |
9857 | end if; | |
9858 | end if; | |
9859 | end if; | |
9860 | ||
9861 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
9862 | if Is_Constrained (T_Typ) then | |
9863 | ||
9864 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
9865 | Exptyp := Get_Actual_Subtype (Expr_Actual); | |
9866 | ||
9867 | if Is_Access_Type (Exptyp) then | |
9868 | Exptyp := Designated_Type (Exptyp); | |
9869 | end if; | |
9870 | ||
9871 | -- String_Literal case. This needs to be handled specially be- | |
9872 | -- cause no index types are available for string literals. The | |
9873 | -- condition is simply: | |
9874 | ||
9875 | -- T_Typ'Length = string-literal-length | |
9876 | ||
9877 | if Nkind (Expr_Actual) = N_String_Literal then | |
9878 | null; | |
9879 | ||
9880 | -- General array case. Here we have a usable actual subtype for | |
9881 | -- the expression, and the condition is built from the two types | |
9882 | ||
9883 | -- T_Typ'First < Exptyp'First or else | |
9884 | -- T_Typ'Last > Exptyp'Last or else | |
9885 | -- T_Typ'First(1) < Exptyp'First(1) or else | |
9886 | -- T_Typ'Last(1) > Exptyp'Last(1) or else | |
9887 | -- ... | |
9888 | ||
9889 | elsif Is_Constrained (Exptyp) then | |
9890 | declare | |
9dfe12ae | 9891 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
9892 | ||
ee6ba406 | 9893 | L_Index : Node_Id; |
9894 | R_Index : Node_Id; | |
ee6ba406 | 9895 | |
9896 | begin | |
9897 | L_Index := First_Index (T_Typ); | |
9898 | R_Index := First_Index (Exptyp); | |
9899 | ||
9900 | for Indx in 1 .. Ndims loop | |
9901 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 9902 | or else |
9903 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 9904 | then |
ee6ba406 | 9905 | -- Deal with compile time length check. Note that we |
9906 | -- skip this in the access case, because the access | |
9907 | -- value may be null, so we cannot know statically. | |
9908 | ||
9909 | if not | |
9910 | Subtypes_Statically_Match | |
9911 | (Etype (L_Index), Etype (R_Index)) | |
9912 | then | |
9913 | -- If the target type is constrained then we | |
9914 | -- have to check for exact equality of bounds | |
9915 | -- (required for qualified expressions). | |
9916 | ||
9917 | if Is_Constrained (T_Typ) then | |
9918 | Evolve_Or_Else | |
9919 | (Cond, | |
9920 | Range_Equal_E_Cond (Exptyp, T_Typ, Indx)); | |
ee6ba406 | 9921 | else |
9922 | Evolve_Or_Else | |
9923 | (Cond, Range_E_Cond (Exptyp, T_Typ, Indx)); | |
9924 | end if; | |
9925 | end if; | |
9926 | ||
9927 | Next (L_Index); | |
9928 | Next (R_Index); | |
ee6ba406 | 9929 | end if; |
9930 | end loop; | |
9931 | end; | |
9932 | ||
9933 | -- Handle cases where we do not get a usable actual subtype that | |
9934 | -- is constrained. This happens for example in the function call | |
9935 | -- and explicit dereference cases. In these cases, we have to get | |
9936 | -- the length or range from the expression itself, making sure we | |
9937 | -- do not evaluate it more than once. | |
9938 | ||
9939 | -- Here Ck_Node is the original expression, or more properly the | |
9940 | -- result of applying Duplicate_Expr to the original tree, | |
9941 | -- forcing the result to be a name. | |
9942 | ||
9943 | else | |
9944 | declare | |
9dfe12ae | 9945 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 9946 | |
9947 | begin | |
9948 | -- Build the condition for the explicit dereference case | |
9949 | ||
9950 | for Indx in 1 .. Ndims loop | |
9951 | Evolve_Or_Else | |
9952 | (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx)); | |
9953 | end loop; | |
9954 | end; | |
ee6ba406 | 9955 | end if; |
9956 | ||
9957 | else | |
feff2f05 | 9958 | -- For a conversion to an unconstrained array type, generate an |
9959 | -- Action to check that the bounds of the source value are within | |
9960 | -- the constraints imposed by the target type (RM 4.6(38)). No | |
9961 | -- check is needed for a conversion to an access to unconstrained | |
9962 | -- array type, as 4.6(24.15/2) requires the designated subtypes | |
9963 | -- of the two access types to statically match. | |
9964 | ||
9965 | if Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
9966 | and then not Do_Access | |
9967 | then | |
ee6ba406 | 9968 | declare |
9969 | Opnd_Index : Node_Id; | |
9970 | Targ_Index : Node_Id; | |
00c403ee | 9971 | Opnd_Range : Node_Id; |
ee6ba406 | 9972 | |
9973 | begin | |
feff2f05 | 9974 | Opnd_Index := First_Index (Get_Actual_Subtype (Ck_Node)); |
ee6ba406 | 9975 | Targ_Index := First_Index (T_Typ); |
00c403ee | 9976 | while Present (Opnd_Index) loop |
9977 | ||
9978 | -- If the index is a range, use its bounds. If it is an | |
9979 | -- entity (as will be the case if it is a named subtype | |
9980 | -- or an itype created for a slice) retrieve its range. | |
9981 | ||
9982 | if Is_Entity_Name (Opnd_Index) | |
9983 | and then Is_Type (Entity (Opnd_Index)) | |
9984 | then | |
9985 | Opnd_Range := Scalar_Range (Entity (Opnd_Index)); | |
9986 | else | |
9987 | Opnd_Range := Opnd_Index; | |
9988 | end if; | |
9989 | ||
9990 | if Nkind (Opnd_Range) = N_Range then | |
9c486805 | 9991 | if Is_In_Range |
9992 | (Low_Bound (Opnd_Range), Etype (Targ_Index), | |
9993 | Assume_Valid => True) | |
ee6ba406 | 9994 | and then |
9995 | Is_In_Range | |
9c486805 | 9996 | (High_Bound (Opnd_Range), Etype (Targ_Index), |
9997 | Assume_Valid => True) | |
ee6ba406 | 9998 | then |
9999 | null; | |
10000 | ||
feff2f05 | 10001 | -- If null range, no check needed |
f2a06be9 | 10002 | |
9dfe12ae | 10003 | elsif |
00c403ee | 10004 | Compile_Time_Known_Value (High_Bound (Opnd_Range)) |
9dfe12ae | 10005 | and then |
00c403ee | 10006 | Compile_Time_Known_Value (Low_Bound (Opnd_Range)) |
9dfe12ae | 10007 | and then |
00c403ee | 10008 | Expr_Value (High_Bound (Opnd_Range)) < |
10009 | Expr_Value (Low_Bound (Opnd_Range)) | |
9dfe12ae | 10010 | then |
10011 | null; | |
10012 | ||
ee6ba406 | 10013 | elsif Is_Out_Of_Range |
9c486805 | 10014 | (Low_Bound (Opnd_Range), Etype (Targ_Index), |
10015 | Assume_Valid => True) | |
ee6ba406 | 10016 | or else |
10017 | Is_Out_Of_Range | |
9c486805 | 10018 | (High_Bound (Opnd_Range), Etype (Targ_Index), |
10019 | Assume_Valid => True) | |
ee6ba406 | 10020 | then |
10021 | Add_Check | |
10022 | (Compile_Time_Constraint_Error | |
cb97ae5c | 10023 | (Wnode, "value out of range of}??", T_Typ)); |
ee6ba406 | 10024 | |
10025 | else | |
10026 | Evolve_Or_Else | |
10027 | (Cond, | |
10028 | Discrete_Range_Cond | |
00c403ee | 10029 | (Opnd_Range, Etype (Targ_Index))); |
ee6ba406 | 10030 | end if; |
10031 | end if; | |
10032 | ||
10033 | Next_Index (Opnd_Index); | |
10034 | Next_Index (Targ_Index); | |
10035 | end loop; | |
10036 | end; | |
10037 | end if; | |
10038 | end if; | |
10039 | end if; | |
10040 | ||
10041 | -- Construct the test and insert into the tree | |
10042 | ||
10043 | if Present (Cond) then | |
10044 | if Do_Access then | |
10045 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
10046 | end if; | |
10047 | ||
f15731c4 | 10048 | Add_Check |
10049 | (Make_Raise_Constraint_Error (Loc, | |
eefa141b | 10050 | Condition => Cond, |
22d3a5a3 | 10051 | Reason => CE_Range_Check_Failed)); |
ee6ba406 | 10052 | end if; |
10053 | ||
10054 | return Ret_Result; | |
ee6ba406 | 10055 | end Selected_Range_Checks; |
10056 | ||
10057 | ------------------------------- | |
10058 | -- Storage_Checks_Suppressed -- | |
10059 | ------------------------------- | |
10060 | ||
10061 | function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is | |
10062 | begin | |
9dfe12ae | 10063 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
10064 | return Is_Check_Suppressed (E, Storage_Check); | |
10065 | else | |
fafc6b97 | 10066 | return Scope_Suppress.Suppress (Storage_Check); |
9dfe12ae | 10067 | end if; |
ee6ba406 | 10068 | end Storage_Checks_Suppressed; |
10069 | ||
10070 | --------------------------- | |
10071 | -- Tag_Checks_Suppressed -- | |
10072 | --------------------------- | |
10073 | ||
10074 | function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is | |
10075 | begin | |
89f1e35c | 10076 | if Present (E) |
10077 | and then Checks_May_Be_Suppressed (E) | |
10078 | then | |
10079 | return Is_Check_Suppressed (E, Tag_Check); | |
20cf157b | 10080 | else |
10081 | return Scope_Suppress.Suppress (Tag_Check); | |
9dfe12ae | 10082 | end if; |
ee6ba406 | 10083 | end Tag_Checks_Suppressed; |
10084 | ||
7b8fa048 | 10085 | --------------------------------------- |
10086 | -- Validate_Alignment_Check_Warnings -- | |
10087 | --------------------------------------- | |
10088 | ||
10089 | procedure Validate_Alignment_Check_Warnings is | |
10090 | begin | |
10091 | for J in Alignment_Warnings.First .. Alignment_Warnings.Last loop | |
10092 | declare | |
10093 | AWR : Alignment_Warnings_Record | |
10094 | renames Alignment_Warnings.Table (J); | |
10095 | begin | |
10096 | if Known_Alignment (AWR.E) | |
10097 | and then AWR.A mod Alignment (AWR.E) = 0 | |
10098 | then | |
10099 | Delete_Warning_And_Continuations (AWR.W); | |
10100 | end if; | |
10101 | end; | |
10102 | end loop; | |
10103 | end Validate_Alignment_Check_Warnings; | |
10104 | ||
0577b0b1 | 10105 | -------------------------- |
10106 | -- Validity_Check_Range -- | |
10107 | -------------------------- | |
10108 | ||
10109 | procedure Validity_Check_Range (N : Node_Id) is | |
10110 | begin | |
10111 | if Validity_Checks_On and Validity_Check_Operands then | |
10112 | if Nkind (N) = N_Range then | |
10113 | Ensure_Valid (Low_Bound (N)); | |
10114 | Ensure_Valid (High_Bound (N)); | |
10115 | end if; | |
10116 | end if; | |
10117 | end Validity_Check_Range; | |
10118 | ||
10119 | -------------------------------- | |
10120 | -- Validity_Checks_Suppressed -- | |
10121 | -------------------------------- | |
10122 | ||
10123 | function Validity_Checks_Suppressed (E : Entity_Id) return Boolean is | |
10124 | begin | |
10125 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
10126 | return Is_Check_Suppressed (E, Validity_Check); | |
10127 | else | |
fafc6b97 | 10128 | return Scope_Suppress.Suppress (Validity_Check); |
0577b0b1 | 10129 | end if; |
10130 | end Validity_Checks_Suppressed; | |
10131 | ||
ee6ba406 | 10132 | end Checks; |