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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 | -- -- | |
e977c0cf | 9 | -- Copyright (C) 1992-2010, 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; | |
27 | with Debug; use Debug; | |
28 | with Einfo; use Einfo; | |
29 | with Errout; use Errout; | |
30 | with Exp_Ch2; use Exp_Ch2; | |
df40eeb0 | 31 | with Exp_Ch4; use Exp_Ch4; |
00c403ee | 32 | with Exp_Ch11; use Exp_Ch11; |
05fcfafb | 33 | with Exp_Pakd; use Exp_Pakd; |
ee6ba406 | 34 | with Exp_Util; use Exp_Util; |
35 | with Elists; use Elists; | |
5329ca64 | 36 | with Eval_Fat; use Eval_Fat; |
ee6ba406 | 37 | with Freeze; use Freeze; |
9dfe12ae | 38 | with Lib; use Lib; |
ee6ba406 | 39 | with Nlists; use Nlists; |
40 | with Nmake; use Nmake; | |
41 | with Opt; use Opt; | |
9dfe12ae | 42 | with Output; use Output; |
c2b56224 | 43 | with Restrict; use Restrict; |
1e16c51c | 44 | with Rident; use Rident; |
ee6ba406 | 45 | with Rtsfind; use Rtsfind; |
46 | with Sem; use Sem; | |
d60c9ff7 | 47 | with Sem_Aux; use Sem_Aux; |
ee6ba406 | 48 | with Sem_Eval; use Sem_Eval; |
00f91aef | 49 | with Sem_Ch3; use Sem_Ch3; |
9dfe12ae | 50 | with Sem_Ch8; use Sem_Ch8; |
ee6ba406 | 51 | with Sem_Res; use Sem_Res; |
52 | with Sem_Util; use Sem_Util; | |
53 | with Sem_Warn; use Sem_Warn; | |
54 | with Sinfo; use Sinfo; | |
9dfe12ae | 55 | with Sinput; use Sinput; |
ee6ba406 | 56 | with Snames; use Snames; |
9dfe12ae | 57 | with Sprint; use Sprint; |
ee6ba406 | 58 | with Stand; use Stand; |
f15731c4 | 59 | with Targparm; use Targparm; |
ee6ba406 | 60 | with Tbuild; use Tbuild; |
61 | with Ttypes; use Ttypes; | |
62 | with Urealp; use Urealp; | |
63 | with Validsw; use Validsw; | |
64 | ||
65 | package body Checks is | |
66 | ||
67 | -- General note: many of these routines are concerned with generating | |
68 | -- checking code to make sure that constraint error is raised at runtime. | |
69 | -- Clearly this code is only needed if the expander is active, since | |
70 | -- otherwise we will not be generating code or going into the runtime | |
71 | -- execution anyway. | |
72 | ||
73 | -- We therefore disconnect most of these checks if the expander is | |
74 | -- inactive. This has the additional benefit that we do not need to | |
75 | -- worry about the tree being messed up by previous errors (since errors | |
76 | -- turn off expansion anyway). | |
77 | ||
78 | -- There are a few exceptions to the above rule. For instance routines | |
79 | -- such as Apply_Scalar_Range_Check that do not insert any code can be | |
80 | -- safely called even when the Expander is inactive (but Errors_Detected | |
81 | -- is 0). The benefit of executing this code when expansion is off, is | |
82 | -- the ability to emit constraint error warning for static expressions | |
83 | -- even when we are not generating code. | |
84 | ||
9dfe12ae | 85 | ------------------------------------- |
86 | -- Suppression of Redundant Checks -- | |
87 | ------------------------------------- | |
88 | ||
89 | -- This unit implements a limited circuit for removal of redundant | |
90 | -- checks. The processing is based on a tracing of simple sequential | |
91 | -- flow. For any sequence of statements, we save expressions that are | |
92 | -- marked to be checked, and then if the same expression appears later | |
93 | -- with the same check, then under certain circumstances, the second | |
94 | -- check can be suppressed. | |
95 | ||
96 | -- Basically, we can suppress the check if we know for certain that | |
97 | -- the previous expression has been elaborated (together with its | |
98 | -- check), and we know that the exception frame is the same, and that | |
99 | -- nothing has happened to change the result of the exception. | |
100 | ||
101 | -- Let us examine each of these three conditions in turn to describe | |
102 | -- how we ensure that this condition is met. | |
103 | ||
104 | -- First, we need to know for certain that the previous expression has | |
6fb3c314 | 105 | -- been executed. This is done principally by the mechanism of calling |
9dfe12ae | 106 | -- Conditional_Statements_Begin at the start of any statement sequence |
107 | -- and Conditional_Statements_End at the end. The End call causes all | |
108 | -- checks remembered since the Begin call to be discarded. This does | |
109 | -- miss a few cases, notably the case of a nested BEGIN-END block with | |
110 | -- no exception handlers. But the important thing is to be conservative. | |
111 | -- The other protection is that all checks are discarded if a label | |
112 | -- is encountered, since then the assumption of sequential execution | |
113 | -- is violated, and we don't know enough about the flow. | |
114 | ||
115 | -- Second, we need to know that the exception frame is the same. We | |
116 | -- do this by killing all remembered checks when we enter a new frame. | |
117 | -- Again, that's over-conservative, but generally the cases we can help | |
118 | -- with are pretty local anyway (like the body of a loop for example). | |
119 | ||
120 | -- Third, we must be sure to forget any checks which are no longer valid. | |
121 | -- This is done by two mechanisms, first the Kill_Checks_Variable call is | |
122 | -- used to note any changes to local variables. We only attempt to deal | |
123 | -- with checks involving local variables, so we do not need to worry | |
124 | -- about global variables. Second, a call to any non-global procedure | |
125 | -- causes us to abandon all stored checks, since such a all may affect | |
126 | -- the values of any local variables. | |
127 | ||
128 | -- The following define the data structures used to deal with remembering | |
129 | -- checks so that redundant checks can be eliminated as described above. | |
130 | ||
131 | -- Right now, the only expressions that we deal with are of the form of | |
132 | -- simple local objects (either declared locally, or IN parameters) or | |
133 | -- such objects plus/minus a compile time known constant. We can do | |
134 | -- more later on if it seems worthwhile, but this catches many simple | |
135 | -- cases in practice. | |
136 | ||
137 | -- The following record type reflects a single saved check. An entry | |
138 | -- is made in the stack of saved checks if and only if the expression | |
139 | -- has been elaborated with the indicated checks. | |
140 | ||
141 | type Saved_Check is record | |
142 | Killed : Boolean; | |
143 | -- Set True if entry is killed by Kill_Checks | |
144 | ||
145 | Entity : Entity_Id; | |
146 | -- The entity involved in the expression that is checked | |
147 | ||
148 | Offset : Uint; | |
149 | -- A compile time value indicating the result of adding or | |
150 | -- subtracting a compile time value. This value is to be | |
151 | -- added to the value of the Entity. A value of zero is | |
152 | -- used for the case of a simple entity reference. | |
153 | ||
154 | Check_Type : Character; | |
155 | -- This is set to 'R' for a range check (in which case Target_Type | |
156 | -- is set to the target type for the range check) or to 'O' for an | |
157 | -- overflow check (in which case Target_Type is set to Empty). | |
158 | ||
159 | Target_Type : Entity_Id; | |
160 | -- Used only if Do_Range_Check is set. Records the target type for | |
161 | -- the check. We need this, because a check is a duplicate only if | |
6fb3c314 | 162 | -- it has the same target type (or more accurately one with a |
9dfe12ae | 163 | -- range that is smaller or equal to the stored target type of a |
164 | -- saved check). | |
165 | end record; | |
166 | ||
167 | -- The following table keeps track of saved checks. Rather than use an | |
168 | -- extensible table. We just use a table of fixed size, and we discard | |
169 | -- any saved checks that do not fit. That's very unlikely to happen and | |
170 | -- this is only an optimization in any case. | |
171 | ||
172 | Saved_Checks : array (Int range 1 .. 200) of Saved_Check; | |
173 | -- Array of saved checks | |
174 | ||
175 | Num_Saved_Checks : Nat := 0; | |
176 | -- Number of saved checks | |
177 | ||
178 | -- The following stack keeps track of statement ranges. It is treated | |
179 | -- as a stack. When Conditional_Statements_Begin is called, an entry | |
180 | -- is pushed onto this stack containing the value of Num_Saved_Checks | |
181 | -- at the time of the call. Then when Conditional_Statements_End is | |
182 | -- called, this value is popped off and used to reset Num_Saved_Checks. | |
183 | ||
184 | -- Note: again, this is a fixed length stack with a size that should | |
185 | -- always be fine. If the value of the stack pointer goes above the | |
186 | -- limit, then we just forget all saved checks. | |
187 | ||
188 | Saved_Checks_Stack : array (Int range 1 .. 100) of Nat; | |
189 | Saved_Checks_TOS : Nat := 0; | |
190 | ||
191 | ----------------------- | |
192 | -- Local Subprograms -- | |
193 | ----------------------- | |
ee6ba406 | 194 | |
5329ca64 | 195 | procedure Apply_Float_Conversion_Check |
196 | (Ck_Node : Node_Id; | |
197 | Target_Typ : Entity_Id); | |
198 | -- The checks on a conversion from a floating-point type to an integer | |
199 | -- type are delicate. They have to be performed before conversion, they | |
200 | -- have to raise an exception when the operand is a NaN, and rounding must | |
201 | -- be taken into account to determine the safe bounds of the operand. | |
202 | ||
ee6ba406 | 203 | procedure Apply_Selected_Length_Checks |
204 | (Ck_Node : Node_Id; | |
205 | Target_Typ : Entity_Id; | |
206 | Source_Typ : Entity_Id; | |
207 | Do_Static : Boolean); | |
208 | -- This is the subprogram that does all the work for Apply_Length_Check | |
209 | -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as | |
210 | -- described for the above routines. The Do_Static flag indicates that | |
211 | -- only a static check is to be done. | |
212 | ||
213 | procedure Apply_Selected_Range_Checks | |
214 | (Ck_Node : Node_Id; | |
215 | Target_Typ : Entity_Id; | |
216 | Source_Typ : Entity_Id; | |
217 | Do_Static : Boolean); | |
218 | -- This is the subprogram that does all the work for Apply_Range_Check. | |
219 | -- Expr, Target_Typ and Source_Typ are as described for the above | |
220 | -- routine. The Do_Static flag indicates that only a static check is | |
221 | -- to be done. | |
222 | ||
2af58f67 | 223 | type Check_Type is new Check_Id range Access_Check .. Division_Check; |
13dbf220 | 224 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean; |
225 | -- This function is used to see if an access or division by zero check is | |
226 | -- needed. The check is to be applied to a single variable appearing in the | |
227 | -- source, and N is the node for the reference. If N is not of this form, | |
228 | -- True is returned with no further processing. If N is of the right form, | |
229 | -- then further processing determines if the given Check is needed. | |
230 | -- | |
231 | -- The particular circuit is to see if we have the case of a check that is | |
232 | -- not needed because it appears in the right operand of a short circuited | |
233 | -- conditional where the left operand guards the check. For example: | |
234 | -- | |
235 | -- if Var = 0 or else Q / Var > 12 then | |
236 | -- ... | |
237 | -- end if; | |
238 | -- | |
239 | -- In this example, the division check is not required. At the same time | |
240 | -- we can issue warnings for suspicious use of non-short-circuited forms, | |
241 | -- such as: | |
242 | -- | |
243 | -- if Var = 0 or Q / Var > 12 then | |
244 | -- ... | |
245 | -- end if; | |
246 | ||
9dfe12ae | 247 | procedure Find_Check |
248 | (Expr : Node_Id; | |
249 | Check_Type : Character; | |
250 | Target_Type : Entity_Id; | |
251 | Entry_OK : out Boolean; | |
252 | Check_Num : out Nat; | |
253 | Ent : out Entity_Id; | |
254 | Ofs : out Uint); | |
255 | -- This routine is used by Enable_Range_Check and Enable_Overflow_Check | |
256 | -- to see if a check is of the form for optimization, and if so, to see | |
257 | -- if it has already been performed. Expr is the expression to check, | |
258 | -- and Check_Type is 'R' for a range check, 'O' for an overflow check. | |
259 | -- Target_Type is the target type for a range check, and Empty for an | |
260 | -- overflow check. If the entry is not of the form for optimization, | |
261 | -- then Entry_OK is set to False, and the remaining out parameters | |
262 | -- are undefined. If the entry is OK, then Ent/Ofs are set to the | |
263 | -- entity and offset from the expression. Check_Num is the number of | |
264 | -- a matching saved entry in Saved_Checks, or zero if no such entry | |
265 | -- is located. | |
266 | ||
ee6ba406 | 267 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id; |
268 | -- If a discriminal is used in constraining a prival, Return reference | |
269 | -- to the discriminal of the protected body (which renames the parameter | |
270 | -- of the enclosing protected operation). This clumsy transformation is | |
271 | -- needed because privals are created too late and their actual subtypes | |
272 | -- are not available when analysing the bodies of the protected operations. | |
0577b0b1 | 273 | -- This function is called whenever the bound is an entity and the scope |
274 | -- indicates a protected operation. If the bound is an in-parameter of | |
275 | -- a protected operation that is not a prival, the function returns the | |
276 | -- bound itself. | |
ee6ba406 | 277 | -- To be cleaned up??? |
278 | ||
279 | function Guard_Access | |
280 | (Cond : Node_Id; | |
281 | Loc : Source_Ptr; | |
314a23b6 | 282 | Ck_Node : Node_Id) return Node_Id; |
ee6ba406 | 283 | -- In the access type case, guard the test with a test to ensure |
284 | -- that the access value is non-null, since the checks do not | |
285 | -- not apply to null access values. | |
286 | ||
287 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr); | |
288 | -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the | |
289 | -- Constraint_Error node. | |
290 | ||
0577b0b1 | 291 | function Range_Or_Validity_Checks_Suppressed |
292 | (Expr : Node_Id) return Boolean; | |
293 | -- Returns True if either range or validity checks or both are suppressed | |
294 | -- for the type of the given expression, or, if the expression is the name | |
295 | -- of an entity, if these checks are suppressed for the entity. | |
296 | ||
ee6ba406 | 297 | function Selected_Length_Checks |
298 | (Ck_Node : Node_Id; | |
299 | Target_Typ : Entity_Id; | |
300 | Source_Typ : Entity_Id; | |
314a23b6 | 301 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 302 | -- Like Apply_Selected_Length_Checks, except it doesn't modify |
303 | -- anything, just returns a list of nodes as described in the spec of | |
304 | -- this package for the Range_Check function. | |
305 | ||
306 | function Selected_Range_Checks | |
307 | (Ck_Node : Node_Id; | |
308 | Target_Typ : Entity_Id; | |
309 | Source_Typ : Entity_Id; | |
314a23b6 | 310 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 311 | -- Like Apply_Selected_Range_Checks, except it doesn't modify anything, |
312 | -- just returns a list of nodes as described in the spec of this package | |
313 | -- for the Range_Check function. | |
314 | ||
315 | ------------------------------ | |
316 | -- Access_Checks_Suppressed -- | |
317 | ------------------------------ | |
318 | ||
319 | function Access_Checks_Suppressed (E : Entity_Id) return Boolean is | |
320 | begin | |
9dfe12ae | 321 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
322 | return Is_Check_Suppressed (E, Access_Check); | |
323 | else | |
324 | return Scope_Suppress (Access_Check); | |
325 | end if; | |
ee6ba406 | 326 | end Access_Checks_Suppressed; |
327 | ||
328 | ------------------------------------- | |
329 | -- Accessibility_Checks_Suppressed -- | |
330 | ------------------------------------- | |
331 | ||
332 | function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is | |
333 | begin | |
9dfe12ae | 334 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
335 | return Is_Check_Suppressed (E, Accessibility_Check); | |
336 | else | |
337 | return Scope_Suppress (Accessibility_Check); | |
338 | end if; | |
ee6ba406 | 339 | end Accessibility_Checks_Suppressed; |
340 | ||
00c403ee | 341 | ----------------------------- |
342 | -- Activate_Division_Check -- | |
343 | ----------------------------- | |
344 | ||
345 | procedure Activate_Division_Check (N : Node_Id) is | |
346 | begin | |
347 | Set_Do_Division_Check (N, True); | |
348 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
349 | end Activate_Division_Check; | |
350 | ||
351 | ----------------------------- | |
352 | -- Activate_Overflow_Check -- | |
353 | ----------------------------- | |
354 | ||
355 | procedure Activate_Overflow_Check (N : Node_Id) is | |
356 | begin | |
357 | Set_Do_Overflow_Check (N, True); | |
358 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
359 | end Activate_Overflow_Check; | |
360 | ||
361 | -------------------------- | |
362 | -- Activate_Range_Check -- | |
363 | -------------------------- | |
364 | ||
365 | procedure Activate_Range_Check (N : Node_Id) is | |
366 | begin | |
367 | Set_Do_Range_Check (N, True); | |
368 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
369 | end Activate_Range_Check; | |
370 | ||
0577b0b1 | 371 | --------------------------------- |
372 | -- Alignment_Checks_Suppressed -- | |
373 | --------------------------------- | |
374 | ||
375 | function Alignment_Checks_Suppressed (E : Entity_Id) return Boolean is | |
376 | begin | |
377 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
378 | return Is_Check_Suppressed (E, Alignment_Check); | |
379 | else | |
380 | return Scope_Suppress (Alignment_Check); | |
381 | end if; | |
382 | end Alignment_Checks_Suppressed; | |
383 | ||
ee6ba406 | 384 | ------------------------- |
385 | -- Append_Range_Checks -- | |
386 | ------------------------- | |
387 | ||
388 | procedure Append_Range_Checks | |
389 | (Checks : Check_Result; | |
390 | Stmts : List_Id; | |
391 | Suppress_Typ : Entity_Id; | |
392 | Static_Sloc : Source_Ptr; | |
393 | Flag_Node : Node_Id) | |
394 | is | |
9dfe12ae | 395 | Internal_Flag_Node : constant Node_Id := Flag_Node; |
396 | Internal_Static_Sloc : constant Source_Ptr := Static_Sloc; | |
397 | ||
ee6ba406 | 398 | Checks_On : constant Boolean := |
399 | (not Index_Checks_Suppressed (Suppress_Typ)) | |
400 | or else | |
401 | (not Range_Checks_Suppressed (Suppress_Typ)); | |
402 | ||
403 | begin | |
404 | -- For now we just return if Checks_On is false, however this should | |
405 | -- be enhanced to check for an always True value in the condition | |
406 | -- and to generate a compilation warning??? | |
407 | ||
408 | if not Checks_On then | |
409 | return; | |
410 | end if; | |
411 | ||
412 | for J in 1 .. 2 loop | |
413 | exit when No (Checks (J)); | |
414 | ||
415 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
416 | and then Present (Condition (Checks (J))) | |
417 | then | |
418 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
419 | Append_To (Stmts, Checks (J)); | |
420 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
421 | end if; | |
422 | ||
423 | else | |
424 | Append_To | |
f15731c4 | 425 | (Stmts, |
426 | Make_Raise_Constraint_Error (Internal_Static_Sloc, | |
427 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 428 | end if; |
429 | end loop; | |
430 | end Append_Range_Checks; | |
431 | ||
432 | ------------------------ | |
433 | -- Apply_Access_Check -- | |
434 | ------------------------ | |
435 | ||
436 | procedure Apply_Access_Check (N : Node_Id) is | |
437 | P : constant Node_Id := Prefix (N); | |
438 | ||
439 | begin | |
13dbf220 | 440 | -- We do not need checks if we are not generating code (i.e. the |
441 | -- expander is not active). This is not just an optimization, there | |
442 | -- are cases (e.g. with pragma Debug) where generating the checks | |
443 | -- can cause real trouble). | |
284faf8b | 444 | |
84d0d4a5 | 445 | if not Expander_Active then |
13dbf220 | 446 | return; |
9dfe12ae | 447 | end if; |
ee6ba406 | 448 | |
84d0d4a5 | 449 | -- No check if short circuiting makes check unnecessary |
9dfe12ae | 450 | |
84d0d4a5 | 451 | if not Check_Needed (P, Access_Check) then |
452 | return; | |
ee6ba406 | 453 | end if; |
9dfe12ae | 454 | |
cc60bd16 | 455 | -- No check if accessing the Offset_To_Top component of a dispatch |
456 | -- table. They are safe by construction. | |
457 | ||
040277b1 | 458 | if Tagged_Type_Expansion |
459 | and then Present (Etype (P)) | |
cc60bd16 | 460 | and then RTU_Loaded (Ada_Tags) |
461 | and then RTE_Available (RE_Offset_To_Top_Ptr) | |
462 | and then Etype (P) = RTE (RE_Offset_To_Top_Ptr) | |
463 | then | |
464 | return; | |
465 | end if; | |
466 | ||
84d0d4a5 | 467 | -- Otherwise go ahead and install the check |
9dfe12ae | 468 | |
fa7497e8 | 469 | Install_Null_Excluding_Check (P); |
ee6ba406 | 470 | end Apply_Access_Check; |
471 | ||
472 | ------------------------------- | |
473 | -- Apply_Accessibility_Check -- | |
474 | ------------------------------- | |
475 | ||
55dc6dc2 | 476 | procedure Apply_Accessibility_Check |
477 | (N : Node_Id; | |
478 | Typ : Entity_Id; | |
479 | Insert_Node : Node_Id) | |
480 | is | |
ee6ba406 | 481 | Loc : constant Source_Ptr := Sloc (N); |
482 | Param_Ent : constant Entity_Id := Param_Entity (N); | |
483 | Param_Level : Node_Id; | |
484 | Type_Level : Node_Id; | |
485 | ||
486 | begin | |
487 | if Inside_A_Generic then | |
488 | return; | |
489 | ||
6ffc64fc | 490 | -- Only apply the run-time check if the access parameter has an |
491 | -- associated extra access level parameter and when the level of the | |
492 | -- type is less deep than the level of the access parameter, and | |
493 | -- accessibility checks are not suppressed. | |
ee6ba406 | 494 | |
495 | elsif Present (Param_Ent) | |
496 | and then Present (Extra_Accessibility (Param_Ent)) | |
6ffc64fc | 497 | and then UI_Gt (Object_Access_Level (N), Type_Access_Level (Typ)) |
ee6ba406 | 498 | and then not Accessibility_Checks_Suppressed (Param_Ent) |
499 | and then not Accessibility_Checks_Suppressed (Typ) | |
500 | then | |
501 | Param_Level := | |
502 | New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc); | |
503 | ||
504 | Type_Level := | |
505 | Make_Integer_Literal (Loc, Type_Access_Level (Typ)); | |
506 | ||
bf3e1520 | 507 | -- Raise Program_Error if the accessibility level of the access |
84d0d4a5 | 508 | -- parameter is deeper than the level of the target access type. |
ee6ba406 | 509 | |
55dc6dc2 | 510 | Insert_Action (Insert_Node, |
ee6ba406 | 511 | Make_Raise_Program_Error (Loc, |
512 | Condition => | |
513 | Make_Op_Gt (Loc, | |
514 | Left_Opnd => Param_Level, | |
f15731c4 | 515 | Right_Opnd => Type_Level), |
516 | Reason => PE_Accessibility_Check_Failed)); | |
ee6ba406 | 517 | |
518 | Analyze_And_Resolve (N); | |
519 | end if; | |
520 | end Apply_Accessibility_Check; | |
521 | ||
0577b0b1 | 522 | -------------------------------- |
523 | -- Apply_Address_Clause_Check -- | |
524 | -------------------------------- | |
525 | ||
526 | procedure Apply_Address_Clause_Check (E : Entity_Id; N : Node_Id) is | |
527 | AC : constant Node_Id := Address_Clause (E); | |
528 | Loc : constant Source_Ptr := Sloc (AC); | |
529 | Typ : constant Entity_Id := Etype (E); | |
530 | Aexp : constant Node_Id := Expression (AC); | |
c2b56224 | 531 | |
c2b56224 | 532 | Expr : Node_Id; |
0577b0b1 | 533 | -- Address expression (not necessarily the same as Aexp, for example |
534 | -- when Aexp is a reference to a constant, in which case Expr gets | |
535 | -- reset to reference the value expression of the constant. | |
536 | ||
0577b0b1 | 537 | procedure Compile_Time_Bad_Alignment; |
538 | -- Post error warnings when alignment is known to be incompatible. Note | |
539 | -- that we do not go as far as inserting a raise of Program_Error since | |
540 | -- this is an erroneous case, and it may happen that we are lucky and an | |
d6da7448 | 541 | -- underaligned address turns out to be OK after all. |
0577b0b1 | 542 | |
543 | -------------------------------- | |
544 | -- Compile_Time_Bad_Alignment -- | |
545 | -------------------------------- | |
546 | ||
547 | procedure Compile_Time_Bad_Alignment is | |
548 | begin | |
d6da7448 | 549 | if Address_Clause_Overlay_Warnings then |
0577b0b1 | 550 | Error_Msg_FE |
551 | ("?specified address for& may be inconsistent with alignment ", | |
552 | Aexp, E); | |
553 | Error_Msg_FE | |
2af58f67 | 554 | ("\?program execution may be erroneous (RM 13.3(27))", |
0577b0b1 | 555 | Aexp, E); |
83f8f0a6 | 556 | Set_Address_Warning_Posted (AC); |
0577b0b1 | 557 | end if; |
558 | end Compile_Time_Bad_Alignment; | |
c2b56224 | 559 | |
2af58f67 | 560 | -- Start of processing for Apply_Address_Clause_Check |
5c61a0ff | 561 | |
c2b56224 | 562 | begin |
d6da7448 | 563 | -- See if alignment check needed. Note that we never need a check if the |
564 | -- maximum alignment is one, since the check will always succeed. | |
565 | ||
566 | -- Note: we do not check for checks suppressed here, since that check | |
567 | -- was done in Sem_Ch13 when the address clause was processed. We are | |
568 | -- only called if checks were not suppressed. The reason for this is | |
569 | -- that we have to delay the call to Apply_Alignment_Check till freeze | |
570 | -- time (so that all types etc are elaborated), but we have to check | |
571 | -- the status of check suppressing at the point of the address clause. | |
572 | ||
573 | if No (AC) | |
574 | or else not Check_Address_Alignment (AC) | |
575 | or else Maximum_Alignment = 1 | |
576 | then | |
577 | return; | |
578 | end if; | |
579 | ||
580 | -- Obtain expression from address clause | |
9dfe12ae | 581 | |
0577b0b1 | 582 | Expr := Expression (AC); |
583 | ||
584 | -- The following loop digs for the real expression to use in the check | |
585 | ||
586 | loop | |
587 | -- For constant, get constant expression | |
588 | ||
589 | if Is_Entity_Name (Expr) | |
590 | and then Ekind (Entity (Expr)) = E_Constant | |
591 | then | |
592 | Expr := Constant_Value (Entity (Expr)); | |
593 | ||
594 | -- For unchecked conversion, get result to convert | |
595 | ||
596 | elsif Nkind (Expr) = N_Unchecked_Type_Conversion then | |
597 | Expr := Expression (Expr); | |
598 | ||
599 | -- For (common case) of To_Address call, get argument | |
600 | ||
601 | elsif Nkind (Expr) = N_Function_Call | |
602 | and then Is_Entity_Name (Name (Expr)) | |
603 | and then Is_RTE (Entity (Name (Expr)), RE_To_Address) | |
604 | then | |
605 | Expr := First (Parameter_Associations (Expr)); | |
606 | ||
607 | if Nkind (Expr) = N_Parameter_Association then | |
608 | Expr := Explicit_Actual_Parameter (Expr); | |
609 | end if; | |
610 | ||
611 | -- We finally have the real expression | |
612 | ||
613 | else | |
614 | exit; | |
615 | end if; | |
616 | end loop; | |
617 | ||
d6da7448 | 618 | -- See if we know that Expr has a bad alignment at compile time |
c2b56224 | 619 | |
620 | if Compile_Time_Known_Value (Expr) | |
f2a06be9 | 621 | and then (Known_Alignment (E) or else Known_Alignment (Typ)) |
c2b56224 | 622 | then |
f2a06be9 | 623 | declare |
624 | AL : Uint := Alignment (Typ); | |
625 | ||
626 | begin | |
627 | -- The object alignment might be more restrictive than the | |
628 | -- type alignment. | |
629 | ||
630 | if Known_Alignment (E) then | |
631 | AL := Alignment (E); | |
632 | end if; | |
633 | ||
634 | if Expr_Value (Expr) mod AL /= 0 then | |
0577b0b1 | 635 | Compile_Time_Bad_Alignment; |
636 | else | |
637 | return; | |
f2a06be9 | 638 | end if; |
639 | end; | |
c2b56224 | 640 | |
0577b0b1 | 641 | -- If the expression has the form X'Address, then we can find out if |
642 | -- the object X has an alignment that is compatible with the object E. | |
d6da7448 | 643 | -- If it hasn't or we don't know, we defer issuing the warning until |
644 | -- the end of the compilation to take into account back end annotations. | |
c2b56224 | 645 | |
0577b0b1 | 646 | elsif Nkind (Expr) = N_Attribute_Reference |
647 | and then Attribute_Name (Expr) = Name_Address | |
d6da7448 | 648 | and then Has_Compatible_Alignment (E, Prefix (Expr)) = Known_Compatible |
0577b0b1 | 649 | then |
d6da7448 | 650 | return; |
0577b0b1 | 651 | end if; |
c2b56224 | 652 | |
6fb3c314 | 653 | -- Here we do not know if the value is acceptable. Strictly we don't |
654 | -- have to do anything, since if the alignment is bad, we have an | |
655 | -- erroneous program. However we are allowed to check for erroneous | |
656 | -- conditions and we decide to do this by default if the check is not | |
657 | -- suppressed. | |
0577b0b1 | 658 | |
659 | -- However, don't do the check if elaboration code is unwanted | |
660 | ||
661 | if Restriction_Active (No_Elaboration_Code) then | |
662 | return; | |
663 | ||
664 | -- Generate a check to raise PE if alignment may be inappropriate | |
665 | ||
666 | else | |
667 | -- If the original expression is a non-static constant, use the | |
668 | -- name of the constant itself rather than duplicating its | |
00c403ee | 669 | -- defining expression, which was extracted above. |
0577b0b1 | 670 | |
00c403ee | 671 | -- Note: Expr is empty if the address-clause is applied to in-mode |
672 | -- actuals (allowed by 13.1(22)). | |
673 | ||
674 | if not Present (Expr) | |
675 | or else | |
676 | (Is_Entity_Name (Expression (AC)) | |
677 | and then Ekind (Entity (Expression (AC))) = E_Constant | |
678 | and then Nkind (Parent (Entity (Expression (AC)))) | |
679 | = N_Object_Declaration) | |
0577b0b1 | 680 | then |
681 | Expr := New_Copy_Tree (Expression (AC)); | |
682 | else | |
683 | Remove_Side_Effects (Expr); | |
c2b56224 | 684 | end if; |
c2b56224 | 685 | |
0577b0b1 | 686 | Insert_After_And_Analyze (N, |
687 | Make_Raise_Program_Error (Loc, | |
688 | Condition => | |
689 | Make_Op_Ne (Loc, | |
690 | Left_Opnd => | |
691 | Make_Op_Mod (Loc, | |
692 | Left_Opnd => | |
693 | Unchecked_Convert_To | |
694 | (RTE (RE_Integer_Address), Expr), | |
695 | Right_Opnd => | |
696 | Make_Attribute_Reference (Loc, | |
697 | Prefix => New_Occurrence_Of (E, Loc), | |
698 | Attribute_Name => Name_Alignment)), | |
699 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
700 | Reason => PE_Misaligned_Address_Value), | |
701 | Suppress => All_Checks); | |
702 | return; | |
703 | end if; | |
9dfe12ae | 704 | |
705 | exception | |
0577b0b1 | 706 | -- If we have some missing run time component in configurable run time |
707 | -- mode then just skip the check (it is not required in any case). | |
708 | ||
9dfe12ae | 709 | when RE_Not_Available => |
710 | return; | |
0577b0b1 | 711 | end Apply_Address_Clause_Check; |
c2b56224 | 712 | |
ee6ba406 | 713 | ------------------------------------- |
714 | -- Apply_Arithmetic_Overflow_Check -- | |
715 | ------------------------------------- | |
716 | ||
f40f9731 | 717 | -- This routine is called only if the type is an integer type, and a |
718 | -- software arithmetic overflow check may be needed for op (add, subtract, | |
719 | -- or multiply). This check is performed only if Software_Overflow_Checking | |
720 | -- is enabled and Do_Overflow_Check is set. In this case we expand the | |
721 | -- operation into a more complex sequence of tests that ensures that | |
722 | -- overflow is properly caught. | |
ee6ba406 | 723 | |
724 | procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is | |
725 | Loc : constant Source_Ptr := Sloc (N); | |
780bfb21 | 726 | Typ : constant Entity_Id := Etype (N); |
727 | Rtyp : constant Entity_Id := Root_Type (Typ); | |
ee6ba406 | 728 | |
729 | begin | |
f40f9731 | 730 | -- An interesting special case. If the arithmetic operation appears as |
731 | -- the operand of a type conversion: | |
732 | ||
733 | -- type1 (x op y) | |
734 | ||
735 | -- and all the following conditions apply: | |
736 | ||
737 | -- arithmetic operation is for a signed integer type | |
738 | -- target type type1 is a static integer subtype | |
739 | -- range of x and y are both included in the range of type1 | |
740 | -- range of x op y is included in the range of type1 | |
741 | -- size of type1 is at least twice the result size of op | |
742 | ||
743 | -- then we don't do an overflow check in any case, instead we transform | |
744 | -- the operation so that we end up with: | |
745 | ||
746 | -- type1 (type1 (x) op type1 (y)) | |
747 | ||
748 | -- This avoids intermediate overflow before the conversion. It is | |
749 | -- explicitly permitted by RM 3.5.4(24): | |
750 | ||
751 | -- For the execution of a predefined operation of a signed integer | |
752 | -- type, the implementation need not raise Constraint_Error if the | |
753 | -- result is outside the base range of the type, so long as the | |
754 | -- correct result is produced. | |
755 | ||
756 | -- It's hard to imagine that any programmer counts on the exception | |
757 | -- being raised in this case, and in any case it's wrong coding to | |
758 | -- have this expectation, given the RM permission. Furthermore, other | |
759 | -- Ada compilers do allow such out of range results. | |
760 | ||
761 | -- Note that we do this transformation even if overflow checking is | |
762 | -- off, since this is precisely about giving the "right" result and | |
763 | -- avoiding the need for an overflow check. | |
764 | ||
8eb4a5eb | 765 | -- Note: this circuit is partially redundant with respect to the similar |
766 | -- processing in Exp_Ch4.Expand_N_Type_Conversion, but the latter deals | |
767 | -- with cases that do not come through here. We still need the following | |
768 | -- processing even with the Exp_Ch4 code in place, since we want to be | |
769 | -- sure not to generate the arithmetic overflow check in these cases | |
770 | -- (Exp_Ch4 would have a hard time removing them once generated). | |
771 | ||
f40f9731 | 772 | if Is_Signed_Integer_Type (Typ) |
773 | and then Nkind (Parent (N)) = N_Type_Conversion | |
ee6ba406 | 774 | then |
f40f9731 | 775 | declare |
776 | Target_Type : constant Entity_Id := | |
777 | Base_Type (Entity (Subtype_Mark (Parent (N)))); | |
778 | ||
779 | Llo, Lhi : Uint; | |
780 | Rlo, Rhi : Uint; | |
781 | LOK, ROK : Boolean; | |
782 | ||
783 | Vlo : Uint; | |
784 | Vhi : Uint; | |
785 | VOK : Boolean; | |
786 | ||
787 | Tlo : Uint; | |
788 | Thi : Uint; | |
789 | ||
790 | begin | |
791 | if Is_Integer_Type (Target_Type) | |
792 | and then RM_Size (Root_Type (Target_Type)) >= 2 * RM_Size (Rtyp) | |
793 | then | |
794 | Tlo := Expr_Value (Type_Low_Bound (Target_Type)); | |
795 | Thi := Expr_Value (Type_High_Bound (Target_Type)); | |
796 | ||
9c486805 | 797 | Determine_Range |
798 | (Left_Opnd (N), LOK, Llo, Lhi, Assume_Valid => True); | |
799 | Determine_Range | |
800 | (Right_Opnd (N), ROK, Rlo, Rhi, Assume_Valid => True); | |
f40f9731 | 801 | |
802 | if (LOK and ROK) | |
803 | and then Tlo <= Llo and then Lhi <= Thi | |
804 | and then Tlo <= Rlo and then Rhi <= Thi | |
805 | then | |
9c486805 | 806 | Determine_Range (N, VOK, Vlo, Vhi, Assume_Valid => True); |
f40f9731 | 807 | |
808 | if VOK and then Tlo <= Vlo and then Vhi <= Thi then | |
809 | Rewrite (Left_Opnd (N), | |
810 | Make_Type_Conversion (Loc, | |
811 | Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), | |
812 | Expression => Relocate_Node (Left_Opnd (N)))); | |
813 | ||
814 | Rewrite (Right_Opnd (N), | |
815 | Make_Type_Conversion (Loc, | |
816 | Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), | |
817 | Expression => Relocate_Node (Right_Opnd (N)))); | |
818 | ||
780bfb21 | 819 | -- Rewrite the conversion operand so that the original |
820 | -- node is retained, in order to avoid the warning for | |
821 | -- redundant conversions in Resolve_Type_Conversion. | |
822 | ||
823 | Rewrite (N, Relocate_Node (N)); | |
824 | ||
f40f9731 | 825 | Set_Etype (N, Target_Type); |
780bfb21 | 826 | |
f40f9731 | 827 | Analyze_And_Resolve (Left_Opnd (N), Target_Type); |
828 | Analyze_And_Resolve (Right_Opnd (N), Target_Type); | |
829 | ||
830 | -- Given that the target type is twice the size of the | |
831 | -- source type, overflow is now impossible, so we can | |
832 | -- safely kill the overflow check and return. | |
833 | ||
834 | Set_Do_Overflow_Check (N, False); | |
835 | return; | |
836 | end if; | |
837 | end if; | |
838 | end if; | |
839 | end; | |
ee6ba406 | 840 | end if; |
841 | ||
f40f9731 | 842 | -- Now see if an overflow check is required |
843 | ||
844 | declare | |
845 | Siz : constant Int := UI_To_Int (Esize (Rtyp)); | |
846 | Dsiz : constant Int := Siz * 2; | |
847 | Opnod : Node_Id; | |
848 | Ctyp : Entity_Id; | |
849 | Opnd : Node_Id; | |
850 | Cent : RE_Id; | |
ee6ba406 | 851 | |
f40f9731 | 852 | begin |
853 | -- Skip check if back end does overflow checks, or the overflow flag | |
df40eeb0 | 854 | -- is not set anyway, or we are not doing code expansion, or the |
855 | -- parent node is a type conversion whose operand is an arithmetic | |
856 | -- operation on signed integers on which the expander can promote | |
bbbed24b | 857 | -- later the operands to type Integer (see Expand_N_Type_Conversion). |
ee6ba406 | 858 | |
f40f9731 | 859 | -- Special case CLI target, where arithmetic overflow checks can be |
860 | -- performed for integer and long_integer | |
ee6ba406 | 861 | |
f40f9731 | 862 | if Backend_Overflow_Checks_On_Target |
863 | or else not Do_Overflow_Check (N) | |
864 | or else not Expander_Active | |
df40eeb0 | 865 | or else (Present (Parent (N)) |
866 | and then Nkind (Parent (N)) = N_Type_Conversion | |
867 | and then Integer_Promotion_Possible (Parent (N))) | |
f40f9731 | 868 | or else |
869 | (VM_Target = CLI_Target and then Siz >= Standard_Integer_Size) | |
870 | then | |
871 | return; | |
872 | end if; | |
ee6ba406 | 873 | |
f40f9731 | 874 | -- Otherwise, generate the full general code for front end overflow |
875 | -- detection, which works by doing arithmetic in a larger type: | |
ee6ba406 | 876 | |
f40f9731 | 877 | -- x op y |
ee6ba406 | 878 | |
f40f9731 | 879 | -- is expanded into |
ee6ba406 | 880 | |
f40f9731 | 881 | -- Typ (Checktyp (x) op Checktyp (y)); |
ee6ba406 | 882 | |
f40f9731 | 883 | -- where Typ is the type of the original expression, and Checktyp is |
884 | -- an integer type of sufficient length to hold the largest possible | |
885 | -- result. | |
ee6ba406 | 886 | |
f40f9731 | 887 | -- If the size of check type exceeds the size of Long_Long_Integer, |
888 | -- we use a different approach, expanding to: | |
ee6ba406 | 889 | |
f40f9731 | 890 | -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y))) |
ee6ba406 | 891 | |
f40f9731 | 892 | -- where xxx is Add, Multiply or Subtract as appropriate |
ee6ba406 | 893 | |
f40f9731 | 894 | -- Find check type if one exists |
895 | ||
896 | if Dsiz <= Standard_Integer_Size then | |
897 | Ctyp := Standard_Integer; | |
ee6ba406 | 898 | |
f40f9731 | 899 | elsif Dsiz <= Standard_Long_Long_Integer_Size then |
900 | Ctyp := Standard_Long_Long_Integer; | |
901 | ||
902 | -- No check type exists, use runtime call | |
ee6ba406 | 903 | |
904 | else | |
f40f9731 | 905 | if Nkind (N) = N_Op_Add then |
906 | Cent := RE_Add_With_Ovflo_Check; | |
ee6ba406 | 907 | |
f40f9731 | 908 | elsif Nkind (N) = N_Op_Multiply then |
909 | Cent := RE_Multiply_With_Ovflo_Check; | |
ee6ba406 | 910 | |
f40f9731 | 911 | else |
912 | pragma Assert (Nkind (N) = N_Op_Subtract); | |
913 | Cent := RE_Subtract_With_Ovflo_Check; | |
914 | end if; | |
915 | ||
916 | Rewrite (N, | |
917 | OK_Convert_To (Typ, | |
918 | Make_Function_Call (Loc, | |
919 | Name => New_Reference_To (RTE (Cent), Loc), | |
920 | Parameter_Associations => New_List ( | |
921 | OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)), | |
922 | OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N)))))); | |
ee6ba406 | 923 | |
f40f9731 | 924 | Analyze_And_Resolve (N, Typ); |
925 | return; | |
926 | end if; | |
ee6ba406 | 927 | |
f40f9731 | 928 | -- If we fall through, we have the case where we do the arithmetic |
929 | -- in the next higher type and get the check by conversion. In these | |
930 | -- cases Ctyp is set to the type to be used as the check type. | |
ee6ba406 | 931 | |
f40f9731 | 932 | Opnod := Relocate_Node (N); |
ee6ba406 | 933 | |
f40f9731 | 934 | Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod)); |
ee6ba406 | 935 | |
f40f9731 | 936 | Analyze (Opnd); |
937 | Set_Etype (Opnd, Ctyp); | |
938 | Set_Analyzed (Opnd, True); | |
939 | Set_Left_Opnd (Opnod, Opnd); | |
ee6ba406 | 940 | |
f40f9731 | 941 | Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod)); |
ee6ba406 | 942 | |
f40f9731 | 943 | Analyze (Opnd); |
944 | Set_Etype (Opnd, Ctyp); | |
945 | Set_Analyzed (Opnd, True); | |
946 | Set_Right_Opnd (Opnod, Opnd); | |
ee6ba406 | 947 | |
f40f9731 | 948 | -- The type of the operation changes to the base type of the check |
949 | -- type, and we reset the overflow check indication, since clearly no | |
950 | -- overflow is possible now that we are using a double length type. | |
951 | -- We also set the Analyzed flag to avoid a recursive attempt to | |
952 | -- expand the node. | |
ee6ba406 | 953 | |
f40f9731 | 954 | Set_Etype (Opnod, Base_Type (Ctyp)); |
955 | Set_Do_Overflow_Check (Opnod, False); | |
956 | Set_Analyzed (Opnod, True); | |
ee6ba406 | 957 | |
f40f9731 | 958 | -- Now build the outer conversion |
ee6ba406 | 959 | |
f40f9731 | 960 | Opnd := OK_Convert_To (Typ, Opnod); |
961 | Analyze (Opnd); | |
962 | Set_Etype (Opnd, Typ); | |
9dfe12ae | 963 | |
f40f9731 | 964 | -- In the discrete type case, we directly generate the range check |
965 | -- for the outer operand. This range check will implement the | |
966 | -- required overflow check. | |
9dfe12ae | 967 | |
f40f9731 | 968 | if Is_Discrete_Type (Typ) then |
969 | Rewrite (N, Opnd); | |
970 | Generate_Range_Check | |
971 | (Expression (N), Typ, CE_Overflow_Check_Failed); | |
9dfe12ae | 972 | |
f40f9731 | 973 | -- For other types, we enable overflow checking on the conversion, |
974 | -- after setting the node as analyzed to prevent recursive attempts | |
975 | -- to expand the conversion node. | |
9dfe12ae | 976 | |
f40f9731 | 977 | else |
978 | Set_Analyzed (Opnd, True); | |
979 | Enable_Overflow_Check (Opnd); | |
980 | Rewrite (N, Opnd); | |
981 | end if; | |
982 | ||
983 | exception | |
984 | when RE_Not_Available => | |
985 | return; | |
986 | end; | |
ee6ba406 | 987 | end Apply_Arithmetic_Overflow_Check; |
988 | ||
ee6ba406 | 989 | ---------------------------- |
990 | -- Apply_Constraint_Check -- | |
991 | ---------------------------- | |
992 | ||
993 | procedure Apply_Constraint_Check | |
994 | (N : Node_Id; | |
995 | Typ : Entity_Id; | |
996 | No_Sliding : Boolean := False) | |
997 | is | |
998 | Desig_Typ : Entity_Id; | |
999 | ||
1000 | begin | |
7aafae1c | 1001 | -- No checks inside a generic (check the instantiations) |
1002 | ||
ee6ba406 | 1003 | if Inside_A_Generic then |
1004 | return; | |
7aafae1c | 1005 | end if; |
ee6ba406 | 1006 | |
6fb3c314 | 1007 | -- Apply required constraint checks |
7aafae1c | 1008 | |
1009 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 1010 | Apply_Scalar_Range_Check (N, Typ); |
1011 | ||
1012 | elsif Is_Array_Type (Typ) then | |
1013 | ||
05fcfafb | 1014 | -- A useful optimization: an aggregate with only an others clause |
5f260d20 | 1015 | -- always has the right bounds. |
1016 | ||
1017 | if Nkind (N) = N_Aggregate | |
1018 | and then No (Expressions (N)) | |
1019 | and then Nkind | |
1020 | (First (Choices (First (Component_Associations (N))))) | |
1021 | = N_Others_Choice | |
1022 | then | |
1023 | return; | |
1024 | end if; | |
1025 | ||
ee6ba406 | 1026 | if Is_Constrained (Typ) then |
1027 | Apply_Length_Check (N, Typ); | |
1028 | ||
1029 | if No_Sliding then | |
1030 | Apply_Range_Check (N, Typ); | |
1031 | end if; | |
1032 | else | |
1033 | Apply_Range_Check (N, Typ); | |
1034 | end if; | |
1035 | ||
1036 | elsif (Is_Record_Type (Typ) | |
1037 | or else Is_Private_Type (Typ)) | |
1038 | and then Has_Discriminants (Base_Type (Typ)) | |
1039 | and then Is_Constrained (Typ) | |
1040 | then | |
1041 | Apply_Discriminant_Check (N, Typ); | |
1042 | ||
1043 | elsif Is_Access_Type (Typ) then | |
1044 | ||
1045 | Desig_Typ := Designated_Type (Typ); | |
1046 | ||
1047 | -- No checks necessary if expression statically null | |
1048 | ||
2af58f67 | 1049 | if Known_Null (N) then |
00c403ee | 1050 | if Can_Never_Be_Null (Typ) then |
1051 | Install_Null_Excluding_Check (N); | |
1052 | end if; | |
ee6ba406 | 1053 | |
1054 | -- No sliding possible on access to arrays | |
1055 | ||
1056 | elsif Is_Array_Type (Desig_Typ) then | |
1057 | if Is_Constrained (Desig_Typ) then | |
1058 | Apply_Length_Check (N, Typ); | |
1059 | end if; | |
1060 | ||
1061 | Apply_Range_Check (N, Typ); | |
1062 | ||
1063 | elsif Has_Discriminants (Base_Type (Desig_Typ)) | |
1064 | and then Is_Constrained (Desig_Typ) | |
1065 | then | |
1066 | Apply_Discriminant_Check (N, Typ); | |
1067 | end if; | |
fa7497e8 | 1068 | |
bf3e1520 | 1069 | -- Apply the 2005 Null_Excluding check. Note that we do not apply |
00c403ee | 1070 | -- this check if the constraint node is illegal, as shown by having |
1071 | -- an error posted. This additional guard prevents cascaded errors | |
1072 | -- and compiler aborts on illegal programs involving Ada 2005 checks. | |
1073 | ||
fa7497e8 | 1074 | if Can_Never_Be_Null (Typ) |
1075 | and then not Can_Never_Be_Null (Etype (N)) | |
00c403ee | 1076 | and then not Error_Posted (N) |
fa7497e8 | 1077 | then |
1078 | Install_Null_Excluding_Check (N); | |
1079 | end if; | |
ee6ba406 | 1080 | end if; |
1081 | end Apply_Constraint_Check; | |
1082 | ||
1083 | ------------------------------ | |
1084 | -- Apply_Discriminant_Check -- | |
1085 | ------------------------------ | |
1086 | ||
1087 | procedure Apply_Discriminant_Check | |
1088 | (N : Node_Id; | |
1089 | Typ : Entity_Id; | |
1090 | Lhs : Node_Id := Empty) | |
1091 | is | |
1092 | Loc : constant Source_Ptr := Sloc (N); | |
1093 | Do_Access : constant Boolean := Is_Access_Type (Typ); | |
1094 | S_Typ : Entity_Id := Etype (N); | |
1095 | Cond : Node_Id; | |
1096 | T_Typ : Entity_Id; | |
1097 | ||
7be5088a | 1098 | function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean; |
1099 | -- A heap object with an indefinite subtype is constrained by its | |
1100 | -- initial value, and assigning to it requires a constraint_check. | |
1101 | -- The target may be an explicit dereference, or a renaming of one. | |
1102 | ||
ee6ba406 | 1103 | function Is_Aliased_Unconstrained_Component return Boolean; |
1104 | -- It is possible for an aliased component to have a nominal | |
1105 | -- unconstrained subtype (through instantiation). If this is a | |
1106 | -- discriminated component assigned in the expansion of an aggregate | |
1107 | -- in an initialization, the check must be suppressed. This unusual | |
2af58f67 | 1108 | -- situation requires a predicate of its own. |
ee6ba406 | 1109 | |
7be5088a | 1110 | ---------------------------------- |
1111 | -- Denotes_Explicit_Dereference -- | |
1112 | ---------------------------------- | |
1113 | ||
1114 | function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean is | |
1115 | begin | |
1116 | return | |
1117 | Nkind (Obj) = N_Explicit_Dereference | |
1118 | or else | |
1119 | (Is_Entity_Name (Obj) | |
1120 | and then Present (Renamed_Object (Entity (Obj))) | |
9474aa9c | 1121 | and then Nkind (Renamed_Object (Entity (Obj))) = |
1122 | N_Explicit_Dereference); | |
7be5088a | 1123 | end Denotes_Explicit_Dereference; |
1124 | ||
ee6ba406 | 1125 | ---------------------------------------- |
1126 | -- Is_Aliased_Unconstrained_Component -- | |
1127 | ---------------------------------------- | |
1128 | ||
1129 | function Is_Aliased_Unconstrained_Component return Boolean is | |
1130 | Comp : Entity_Id; | |
1131 | Pref : Node_Id; | |
1132 | ||
1133 | begin | |
1134 | if Nkind (Lhs) /= N_Selected_Component then | |
1135 | return False; | |
1136 | else | |
1137 | Comp := Entity (Selector_Name (Lhs)); | |
1138 | Pref := Prefix (Lhs); | |
1139 | end if; | |
1140 | ||
1141 | if Ekind (Comp) /= E_Component | |
1142 | or else not Is_Aliased (Comp) | |
1143 | then | |
1144 | return False; | |
1145 | end if; | |
1146 | ||
1147 | return not Comes_From_Source (Pref) | |
1148 | and then In_Instance | |
1149 | and then not Is_Constrained (Etype (Comp)); | |
1150 | end Is_Aliased_Unconstrained_Component; | |
1151 | ||
1152 | -- Start of processing for Apply_Discriminant_Check | |
1153 | ||
1154 | begin | |
1155 | if Do_Access then | |
1156 | T_Typ := Designated_Type (Typ); | |
1157 | else | |
1158 | T_Typ := Typ; | |
1159 | end if; | |
1160 | ||
1161 | -- Nothing to do if discriminant checks are suppressed or else no code | |
1162 | -- is to be generated | |
1163 | ||
1164 | if not Expander_Active | |
1165 | or else Discriminant_Checks_Suppressed (T_Typ) | |
1166 | then | |
1167 | return; | |
1168 | end if; | |
1169 | ||
feff2f05 | 1170 | -- No discriminant checks necessary for an access when expression is |
1171 | -- statically Null. This is not only an optimization, it is fundamental | |
1172 | -- because otherwise discriminant checks may be generated in init procs | |
1173 | -- for types containing an access to a not-yet-frozen record, causing a | |
1174 | -- deadly forward reference. | |
ee6ba406 | 1175 | |
feff2f05 | 1176 | -- Also, if the expression is of an access type whose designated type is |
1177 | -- incomplete, then the access value must be null and we suppress the | |
1178 | -- check. | |
ee6ba406 | 1179 | |
2af58f67 | 1180 | if Known_Null (N) then |
ee6ba406 | 1181 | return; |
1182 | ||
1183 | elsif Is_Access_Type (S_Typ) then | |
1184 | S_Typ := Designated_Type (S_Typ); | |
1185 | ||
1186 | if Ekind (S_Typ) = E_Incomplete_Type then | |
1187 | return; | |
1188 | end if; | |
1189 | end if; | |
1190 | ||
0577b0b1 | 1191 | -- If an assignment target is present, then we need to generate the |
1192 | -- actual subtype if the target is a parameter or aliased object with | |
1193 | -- an unconstrained nominal subtype. | |
1194 | ||
1195 | -- Ada 2005 (AI-363): For Ada 2005, we limit the building of the actual | |
1196 | -- subtype to the parameter and dereference cases, since other aliased | |
1197 | -- objects are unconstrained (unless the nominal subtype is explicitly | |
7be5088a | 1198 | -- constrained). |
ee6ba406 | 1199 | |
1200 | if Present (Lhs) | |
1201 | and then (Present (Param_Entity (Lhs)) | |
de54c5ab | 1202 | or else (Ada_Version < Ada_2005 |
0577b0b1 | 1203 | and then not Is_Constrained (T_Typ) |
ee6ba406 | 1204 | and then Is_Aliased_View (Lhs) |
0577b0b1 | 1205 | and then not Is_Aliased_Unconstrained_Component) |
de54c5ab | 1206 | or else (Ada_Version >= Ada_2005 |
0577b0b1 | 1207 | and then not Is_Constrained (T_Typ) |
7be5088a | 1208 | and then Denotes_Explicit_Dereference (Lhs) |
0577b0b1 | 1209 | and then Nkind (Original_Node (Lhs)) /= |
1210 | N_Function_Call)) | |
ee6ba406 | 1211 | then |
1212 | T_Typ := Get_Actual_Subtype (Lhs); | |
1213 | end if; | |
1214 | ||
feff2f05 | 1215 | -- Nothing to do if the type is unconstrained (this is the case where |
1216 | -- the actual subtype in the RM sense of N is unconstrained and no check | |
1217 | -- is required). | |
ee6ba406 | 1218 | |
1219 | if not Is_Constrained (T_Typ) then | |
1220 | return; | |
05fcfafb | 1221 | |
1222 | -- Ada 2005: nothing to do if the type is one for which there is a | |
1223 | -- partial view that is constrained. | |
1224 | ||
de54c5ab | 1225 | elsif Ada_Version >= Ada_2005 |
05fcfafb | 1226 | and then Has_Constrained_Partial_View (Base_Type (T_Typ)) |
1227 | then | |
1228 | return; | |
ee6ba406 | 1229 | end if; |
1230 | ||
00f91aef | 1231 | -- Nothing to do if the type is an Unchecked_Union |
1232 | ||
1233 | if Is_Unchecked_Union (Base_Type (T_Typ)) then | |
1234 | return; | |
1235 | end if; | |
1236 | ||
feff2f05 | 1237 | -- Suppress checks if the subtypes are the same. the check must be |
1238 | -- preserved in an assignment to a formal, because the constraint is | |
1239 | -- given by the actual. | |
ee6ba406 | 1240 | |
1241 | if Nkind (Original_Node (N)) /= N_Allocator | |
1242 | and then (No (Lhs) | |
1243 | or else not Is_Entity_Name (Lhs) | |
9dfe12ae | 1244 | or else No (Param_Entity (Lhs))) |
ee6ba406 | 1245 | then |
1246 | if (Etype (N) = Typ | |
1247 | or else (Do_Access and then Designated_Type (Typ) = S_Typ)) | |
1248 | and then not Is_Aliased_View (Lhs) | |
1249 | then | |
1250 | return; | |
1251 | end if; | |
1252 | ||
feff2f05 | 1253 | -- We can also eliminate checks on allocators with a subtype mark that |
1254 | -- coincides with the context type. The context type may be a subtype | |
1255 | -- without a constraint (common case, a generic actual). | |
ee6ba406 | 1256 | |
1257 | elsif Nkind (Original_Node (N)) = N_Allocator | |
1258 | and then Is_Entity_Name (Expression (Original_Node (N))) | |
1259 | then | |
1260 | declare | |
9dfe12ae | 1261 | Alloc_Typ : constant Entity_Id := |
1262 | Entity (Expression (Original_Node (N))); | |
ee6ba406 | 1263 | |
1264 | begin | |
1265 | if Alloc_Typ = T_Typ | |
1266 | or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration | |
1267 | and then Is_Entity_Name ( | |
1268 | Subtype_Indication (Parent (T_Typ))) | |
1269 | and then Alloc_Typ = Base_Type (T_Typ)) | |
1270 | ||
1271 | then | |
1272 | return; | |
1273 | end if; | |
1274 | end; | |
1275 | end if; | |
1276 | ||
feff2f05 | 1277 | -- See if we have a case where the types are both constrained, and all |
1278 | -- the constraints are constants. In this case, we can do the check | |
1279 | -- successfully at compile time. | |
ee6ba406 | 1280 | |
9dfe12ae | 1281 | -- We skip this check for the case where the node is a rewritten` |
ee6ba406 | 1282 | -- allocator, because it already carries the context subtype, and |
1283 | -- extracting the discriminants from the aggregate is messy. | |
1284 | ||
1285 | if Is_Constrained (S_Typ) | |
1286 | and then Nkind (Original_Node (N)) /= N_Allocator | |
1287 | then | |
1288 | declare | |
1289 | DconT : Elmt_Id; | |
1290 | Discr : Entity_Id; | |
1291 | DconS : Elmt_Id; | |
1292 | ItemS : Node_Id; | |
1293 | ItemT : Node_Id; | |
1294 | ||
1295 | begin | |
1296 | -- S_Typ may not have discriminants in the case where it is a | |
feff2f05 | 1297 | -- private type completed by a default discriminated type. In that |
1298 | -- case, we need to get the constraints from the underlying_type. | |
1299 | -- If the underlying type is unconstrained (i.e. has no default | |
1300 | -- discriminants) no check is needed. | |
ee6ba406 | 1301 | |
1302 | if Has_Discriminants (S_Typ) then | |
1303 | Discr := First_Discriminant (S_Typ); | |
1304 | DconS := First_Elmt (Discriminant_Constraint (S_Typ)); | |
1305 | ||
1306 | else | |
1307 | Discr := First_Discriminant (Underlying_Type (S_Typ)); | |
1308 | DconS := | |
1309 | First_Elmt | |
1310 | (Discriminant_Constraint (Underlying_Type (S_Typ))); | |
1311 | ||
1312 | if No (DconS) then | |
1313 | return; | |
1314 | end if; | |
fccb5da7 | 1315 | |
1316 | -- A further optimization: if T_Typ is derived from S_Typ | |
1317 | -- without imposing a constraint, no check is needed. | |
1318 | ||
1319 | if Nkind (Original_Node (Parent (T_Typ))) = | |
1320 | N_Full_Type_Declaration | |
1321 | then | |
1322 | declare | |
5c61a0ff | 1323 | Type_Def : constant Node_Id := |
fccb5da7 | 1324 | Type_Definition |
1325 | (Original_Node (Parent (T_Typ))); | |
1326 | begin | |
1327 | if Nkind (Type_Def) = N_Derived_Type_Definition | |
1328 | and then Is_Entity_Name (Subtype_Indication (Type_Def)) | |
1329 | and then Entity (Subtype_Indication (Type_Def)) = S_Typ | |
1330 | then | |
1331 | return; | |
1332 | end if; | |
1333 | end; | |
1334 | end if; | |
ee6ba406 | 1335 | end if; |
1336 | ||
1337 | DconT := First_Elmt (Discriminant_Constraint (T_Typ)); | |
1338 | ||
1339 | while Present (Discr) loop | |
1340 | ItemS := Node (DconS); | |
1341 | ItemT := Node (DconT); | |
1342 | ||
00c403ee | 1343 | -- For a discriminated component type constrained by the |
1344 | -- current instance of an enclosing type, there is no | |
1345 | -- applicable discriminant check. | |
1346 | ||
1347 | if Nkind (ItemT) = N_Attribute_Reference | |
1348 | and then Is_Access_Type (Etype (ItemT)) | |
1349 | and then Is_Entity_Name (Prefix (ItemT)) | |
1350 | and then Is_Type (Entity (Prefix (ItemT))) | |
1351 | then | |
1352 | return; | |
1353 | end if; | |
1354 | ||
cc60bd16 | 1355 | -- If the expressions for the discriminants are identical |
1356 | -- and it is side-effect free (for now just an entity), | |
1357 | -- this may be a shared constraint, e.g. from a subtype | |
1358 | -- without a constraint introduced as a generic actual. | |
1359 | -- Examine other discriminants if any. | |
1360 | ||
1361 | if ItemS = ItemT | |
1362 | and then Is_Entity_Name (ItemS) | |
1363 | then | |
1364 | null; | |
1365 | ||
1366 | elsif not Is_OK_Static_Expression (ItemS) | |
1367 | or else not Is_OK_Static_Expression (ItemT) | |
1368 | then | |
1369 | exit; | |
ee6ba406 | 1370 | |
cc60bd16 | 1371 | elsif Expr_Value (ItemS) /= Expr_Value (ItemT) then |
ee6ba406 | 1372 | if Do_Access then -- needs run-time check. |
1373 | exit; | |
1374 | else | |
1375 | Apply_Compile_Time_Constraint_Error | |
f15731c4 | 1376 | (N, "incorrect value for discriminant&?", |
1377 | CE_Discriminant_Check_Failed, Ent => Discr); | |
ee6ba406 | 1378 | return; |
1379 | end if; | |
1380 | end if; | |
1381 | ||
1382 | Next_Elmt (DconS); | |
1383 | Next_Elmt (DconT); | |
1384 | Next_Discriminant (Discr); | |
1385 | end loop; | |
1386 | ||
1387 | if No (Discr) then | |
1388 | return; | |
1389 | end if; | |
1390 | end; | |
1391 | end if; | |
1392 | ||
1393 | -- Here we need a discriminant check. First build the expression | |
1394 | -- for the comparisons of the discriminants: | |
1395 | ||
1396 | -- (n.disc1 /= typ.disc1) or else | |
1397 | -- (n.disc2 /= typ.disc2) or else | |
1398 | -- ... | |
1399 | -- (n.discn /= typ.discn) | |
1400 | ||
1401 | Cond := Build_Discriminant_Checks (N, T_Typ); | |
1402 | ||
1403 | -- If Lhs is set and is a parameter, then the condition is | |
1404 | -- guarded by: lhs'constrained and then (condition built above) | |
1405 | ||
1406 | if Present (Param_Entity (Lhs)) then | |
1407 | Cond := | |
1408 | Make_And_Then (Loc, | |
1409 | Left_Opnd => | |
1410 | Make_Attribute_Reference (Loc, | |
1411 | Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc), | |
1412 | Attribute_Name => Name_Constrained), | |
1413 | Right_Opnd => Cond); | |
1414 | end if; | |
1415 | ||
1416 | if Do_Access then | |
1417 | Cond := Guard_Access (Cond, Loc, N); | |
1418 | end if; | |
1419 | ||
1420 | Insert_Action (N, | |
f15731c4 | 1421 | Make_Raise_Constraint_Error (Loc, |
1422 | Condition => Cond, | |
1423 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 1424 | end Apply_Discriminant_Check; |
1425 | ||
1426 | ------------------------ | |
1427 | -- Apply_Divide_Check -- | |
1428 | ------------------------ | |
1429 | ||
1430 | procedure Apply_Divide_Check (N : Node_Id) is | |
1431 | Loc : constant Source_Ptr := Sloc (N); | |
1432 | Typ : constant Entity_Id := Etype (N); | |
1433 | Left : constant Node_Id := Left_Opnd (N); | |
1434 | Right : constant Node_Id := Right_Opnd (N); | |
1435 | ||
1436 | LLB : Uint; | |
1437 | Llo : Uint; | |
1438 | Lhi : Uint; | |
1439 | LOK : Boolean; | |
1440 | Rlo : Uint; | |
1441 | Rhi : Uint; | |
96da3284 | 1442 | ROK : Boolean; |
1443 | ||
1444 | pragma Warnings (Off, Lhi); | |
1445 | -- Don't actually use this value | |
ee6ba406 | 1446 | |
1447 | begin | |
1448 | if Expander_Active | |
13dbf220 | 1449 | and then not Backend_Divide_Checks_On_Target |
1450 | and then Check_Needed (Right, Division_Check) | |
ee6ba406 | 1451 | then |
9c486805 | 1452 | Determine_Range (Right, ROK, Rlo, Rhi, Assume_Valid => True); |
ee6ba406 | 1453 | |
1454 | -- See if division by zero possible, and if so generate test. This | |
1455 | -- part of the test is not controlled by the -gnato switch. | |
1456 | ||
1457 | if Do_Division_Check (N) then | |
ee6ba406 | 1458 | if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then |
1459 | Insert_Action (N, | |
1460 | Make_Raise_Constraint_Error (Loc, | |
1461 | Condition => | |
1462 | Make_Op_Eq (Loc, | |
0577b0b1 | 1463 | Left_Opnd => Duplicate_Subexpr_Move_Checks (Right), |
f15731c4 | 1464 | Right_Opnd => Make_Integer_Literal (Loc, 0)), |
1465 | Reason => CE_Divide_By_Zero)); | |
ee6ba406 | 1466 | end if; |
1467 | end if; | |
1468 | ||
1469 | -- Test for extremely annoying case of xxx'First divided by -1 | |
1470 | ||
1471 | if Do_Overflow_Check (N) then | |
ee6ba406 | 1472 | if Nkind (N) = N_Op_Divide |
1473 | and then Is_Signed_Integer_Type (Typ) | |
1474 | then | |
9c486805 | 1475 | Determine_Range (Left, LOK, Llo, Lhi, Assume_Valid => True); |
ee6ba406 | 1476 | LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ))); |
1477 | ||
1478 | if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) | |
1479 | and then | |
1480 | ((not LOK) or else (Llo = LLB)) | |
1481 | then | |
1482 | Insert_Action (N, | |
1483 | Make_Raise_Constraint_Error (Loc, | |
1484 | Condition => | |
1485 | Make_And_Then (Loc, | |
1486 | ||
1487 | Make_Op_Eq (Loc, | |
9dfe12ae | 1488 | Left_Opnd => |
1489 | Duplicate_Subexpr_Move_Checks (Left), | |
ee6ba406 | 1490 | Right_Opnd => Make_Integer_Literal (Loc, LLB)), |
1491 | ||
1492 | Make_Op_Eq (Loc, | |
9dfe12ae | 1493 | Left_Opnd => |
1494 | Duplicate_Subexpr (Right), | |
ee6ba406 | 1495 | Right_Opnd => |
f15731c4 | 1496 | Make_Integer_Literal (Loc, -1))), |
1497 | Reason => CE_Overflow_Check_Failed)); | |
ee6ba406 | 1498 | end if; |
1499 | end if; | |
1500 | end if; | |
1501 | end if; | |
1502 | end Apply_Divide_Check; | |
1503 | ||
5329ca64 | 1504 | ---------------------------------- |
1505 | -- Apply_Float_Conversion_Check -- | |
1506 | ---------------------------------- | |
1507 | ||
feff2f05 | 1508 | -- Let F and I be the source and target types of the conversion. The RM |
1509 | -- specifies that a floating-point value X is rounded to the nearest | |
1510 | -- integer, with halfway cases being rounded away from zero. The rounded | |
1511 | -- value of X is checked against I'Range. | |
1512 | ||
1513 | -- The catch in the above paragraph is that there is no good way to know | |
1514 | -- whether the round-to-integer operation resulted in overflow. A remedy is | |
1515 | -- to perform a range check in the floating-point domain instead, however: | |
5329ca64 | 1516 | |
5329ca64 | 1517 | -- (1) The bounds may not be known at compile time |
2af58f67 | 1518 | -- (2) The check must take into account rounding or truncation. |
5329ca64 | 1519 | -- (3) The range of type I may not be exactly representable in F. |
2af58f67 | 1520 | -- (4) For the rounding case, The end-points I'First - 0.5 and |
1521 | -- I'Last + 0.5 may or may not be in range, depending on the | |
1522 | -- sign of I'First and I'Last. | |
5329ca64 | 1523 | -- (5) X may be a NaN, which will fail any comparison |
1524 | ||
2af58f67 | 1525 | -- The following steps correctly convert X with rounding: |
feff2f05 | 1526 | |
5329ca64 | 1527 | -- (1) If either I'First or I'Last is not known at compile time, use |
1528 | -- I'Base instead of I in the next three steps and perform a | |
1529 | -- regular range check against I'Range after conversion. | |
1530 | -- (2) If I'First - 0.5 is representable in F then let Lo be that | |
1531 | -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be | |
2af58f67 | 1532 | -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First). |
1533 | -- In other words, take one of the closest floating-point numbers | |
1534 | -- (which is an integer value) to I'First, and see if it is in | |
1535 | -- range or not. | |
5329ca64 | 1536 | -- (3) If I'Last + 0.5 is representable in F then let Hi be that value |
1537 | -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be | |
2af58f67 | 1538 | -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last). |
5329ca64 | 1539 | -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo) |
1540 | -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi) | |
1541 | ||
2af58f67 | 1542 | -- For the truncating case, replace steps (2) and (3) as follows: |
1543 | -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK | |
1544 | -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let | |
1545 | -- Lo_OK be True. | |
1546 | -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK | |
1547 | -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let | |
1548 | -- Hi_OK be False | |
1549 | ||
5329ca64 | 1550 | procedure Apply_Float_Conversion_Check |
1551 | (Ck_Node : Node_Id; | |
1552 | Target_Typ : Entity_Id) | |
1553 | is | |
feff2f05 | 1554 | LB : constant Node_Id := Type_Low_Bound (Target_Typ); |
1555 | HB : constant Node_Id := Type_High_Bound (Target_Typ); | |
5329ca64 | 1556 | Loc : constant Source_Ptr := Sloc (Ck_Node); |
1557 | Expr_Type : constant Entity_Id := Base_Type (Etype (Ck_Node)); | |
feff2f05 | 1558 | Target_Base : constant Entity_Id := |
1559 | Implementation_Base_Type (Target_Typ); | |
1560 | ||
2af58f67 | 1561 | Par : constant Node_Id := Parent (Ck_Node); |
1562 | pragma Assert (Nkind (Par) = N_Type_Conversion); | |
1563 | -- Parent of check node, must be a type conversion | |
1564 | ||
1565 | Truncate : constant Boolean := Float_Truncate (Par); | |
1566 | Max_Bound : constant Uint := | |
1567 | UI_Expon | |
e8548746 | 1568 | (Machine_Radix_Value (Expr_Type), |
1569 | Machine_Mantissa_Value (Expr_Type) - 1) - 1; | |
2af58f67 | 1570 | |
5329ca64 | 1571 | -- Largest bound, so bound plus or minus half is a machine number of F |
1572 | ||
feff2f05 | 1573 | Ifirst, Ilast : Uint; |
1574 | -- Bounds of integer type | |
1575 | ||
1576 | Lo, Hi : Ureal; | |
1577 | -- Bounds to check in floating-point domain | |
5329ca64 | 1578 | |
feff2f05 | 1579 | Lo_OK, Hi_OK : Boolean; |
1580 | -- True iff Lo resp. Hi belongs to I'Range | |
5329ca64 | 1581 | |
feff2f05 | 1582 | Lo_Chk, Hi_Chk : Node_Id; |
1583 | -- Expressions that are False iff check fails | |
1584 | ||
1585 | Reason : RT_Exception_Code; | |
5329ca64 | 1586 | |
1587 | begin | |
1588 | if not Compile_Time_Known_Value (LB) | |
1589 | or not Compile_Time_Known_Value (HB) | |
1590 | then | |
1591 | declare | |
feff2f05 | 1592 | -- First check that the value falls in the range of the base type, |
1593 | -- to prevent overflow during conversion and then perform a | |
1594 | -- regular range check against the (dynamic) bounds. | |
5329ca64 | 1595 | |
5329ca64 | 1596 | pragma Assert (Target_Base /= Target_Typ); |
5329ca64 | 1597 | |
46eb6933 | 1598 | Temp : constant Entity_Id := Make_Temporary (Loc, 'T', Par); |
5329ca64 | 1599 | |
1600 | begin | |
1601 | Apply_Float_Conversion_Check (Ck_Node, Target_Base); | |
1602 | Set_Etype (Temp, Target_Base); | |
1603 | ||
1604 | Insert_Action (Parent (Par), | |
1605 | Make_Object_Declaration (Loc, | |
1606 | Defining_Identifier => Temp, | |
1607 | Object_Definition => New_Occurrence_Of (Target_Typ, Loc), | |
1608 | Expression => New_Copy_Tree (Par)), | |
1609 | Suppress => All_Checks); | |
1610 | ||
1611 | Insert_Action (Par, | |
1612 | Make_Raise_Constraint_Error (Loc, | |
1613 | Condition => | |
1614 | Make_Not_In (Loc, | |
1615 | Left_Opnd => New_Occurrence_Of (Temp, Loc), | |
1616 | Right_Opnd => New_Occurrence_Of (Target_Typ, Loc)), | |
1617 | Reason => CE_Range_Check_Failed)); | |
1618 | Rewrite (Par, New_Occurrence_Of (Temp, Loc)); | |
1619 | ||
1620 | return; | |
1621 | end; | |
1622 | end if; | |
1623 | ||
7d86aa98 | 1624 | -- Get the (static) bounds of the target type |
5329ca64 | 1625 | |
1626 | Ifirst := Expr_Value (LB); | |
1627 | Ilast := Expr_Value (HB); | |
1628 | ||
7d86aa98 | 1629 | -- A simple optimization: if the expression is a universal literal, |
1630 | -- we can do the comparison with the bounds and the conversion to | |
1631 | -- an integer type statically. The range checks are unchanged. | |
1632 | ||
1633 | if Nkind (Ck_Node) = N_Real_Literal | |
1634 | and then Etype (Ck_Node) = Universal_Real | |
1635 | and then Is_Integer_Type (Target_Typ) | |
1636 | and then Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
1637 | then | |
1638 | declare | |
1639 | Int_Val : constant Uint := UR_To_Uint (Realval (Ck_Node)); | |
1640 | ||
1641 | begin | |
1642 | if Int_Val <= Ilast and then Int_Val >= Ifirst then | |
1643 | ||
4309515d | 1644 | -- Conversion is safe |
7d86aa98 | 1645 | |
1646 | Rewrite (Parent (Ck_Node), | |
1647 | Make_Integer_Literal (Loc, UI_To_Int (Int_Val))); | |
1648 | Analyze_And_Resolve (Parent (Ck_Node), Target_Typ); | |
1649 | return; | |
1650 | end if; | |
1651 | end; | |
1652 | end if; | |
1653 | ||
5329ca64 | 1654 | -- Check against lower bound |
1655 | ||
2af58f67 | 1656 | if Truncate and then Ifirst > 0 then |
1657 | Lo := Pred (Expr_Type, UR_From_Uint (Ifirst)); | |
1658 | Lo_OK := False; | |
1659 | ||
1660 | elsif Truncate then | |
1661 | Lo := Succ (Expr_Type, UR_From_Uint (Ifirst - 1)); | |
1662 | Lo_OK := True; | |
1663 | ||
1664 | elsif abs (Ifirst) < Max_Bound then | |
5329ca64 | 1665 | Lo := UR_From_Uint (Ifirst) - Ureal_Half; |
1666 | Lo_OK := (Ifirst > 0); | |
2af58f67 | 1667 | |
5329ca64 | 1668 | else |
1669 | Lo := Machine (Expr_Type, UR_From_Uint (Ifirst), Round_Even, Ck_Node); | |
1670 | Lo_OK := (Lo >= UR_From_Uint (Ifirst)); | |
1671 | end if; | |
1672 | ||
1673 | if Lo_OK then | |
1674 | ||
1675 | -- Lo_Chk := (X >= Lo) | |
1676 | ||
1677 | Lo_Chk := Make_Op_Ge (Loc, | |
1678 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1679 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
1680 | ||
1681 | else | |
1682 | -- Lo_Chk := (X > Lo) | |
1683 | ||
1684 | Lo_Chk := Make_Op_Gt (Loc, | |
1685 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1686 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
1687 | end if; | |
1688 | ||
1689 | -- Check against higher bound | |
1690 | ||
2af58f67 | 1691 | if Truncate and then Ilast < 0 then |
1692 | Hi := Succ (Expr_Type, UR_From_Uint (Ilast)); | |
1693 | Lo_OK := False; | |
1694 | ||
1695 | elsif Truncate then | |
1696 | Hi := Pred (Expr_Type, UR_From_Uint (Ilast + 1)); | |
1697 | Hi_OK := True; | |
1698 | ||
1699 | elsif abs (Ilast) < Max_Bound then | |
5329ca64 | 1700 | Hi := UR_From_Uint (Ilast) + Ureal_Half; |
1701 | Hi_OK := (Ilast < 0); | |
1702 | else | |
1703 | Hi := Machine (Expr_Type, UR_From_Uint (Ilast), Round_Even, Ck_Node); | |
1704 | Hi_OK := (Hi <= UR_From_Uint (Ilast)); | |
1705 | end if; | |
1706 | ||
1707 | if Hi_OK then | |
1708 | ||
1709 | -- Hi_Chk := (X <= Hi) | |
1710 | ||
1711 | Hi_Chk := Make_Op_Le (Loc, | |
1712 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1713 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
1714 | ||
1715 | else | |
1716 | -- Hi_Chk := (X < Hi) | |
1717 | ||
1718 | Hi_Chk := Make_Op_Lt (Loc, | |
1719 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1720 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
1721 | end if; | |
1722 | ||
feff2f05 | 1723 | -- If the bounds of the target type are the same as those of the base |
1724 | -- type, the check is an overflow check as a range check is not | |
1725 | -- performed in these cases. | |
5329ca64 | 1726 | |
1727 | if Expr_Value (Type_Low_Bound (Target_Base)) = Ifirst | |
1728 | and then Expr_Value (Type_High_Bound (Target_Base)) = Ilast | |
1729 | then | |
1730 | Reason := CE_Overflow_Check_Failed; | |
1731 | else | |
1732 | Reason := CE_Range_Check_Failed; | |
1733 | end if; | |
1734 | ||
1735 | -- Raise CE if either conditions does not hold | |
1736 | ||
1737 | Insert_Action (Ck_Node, | |
1738 | Make_Raise_Constraint_Error (Loc, | |
05fcfafb | 1739 | Condition => Make_Op_Not (Loc, Make_And_Then (Loc, Lo_Chk, Hi_Chk)), |
5329ca64 | 1740 | Reason => Reason)); |
1741 | end Apply_Float_Conversion_Check; | |
1742 | ||
ee6ba406 | 1743 | ------------------------ |
1744 | -- Apply_Length_Check -- | |
1745 | ------------------------ | |
1746 | ||
1747 | procedure Apply_Length_Check | |
1748 | (Ck_Node : Node_Id; | |
1749 | Target_Typ : Entity_Id; | |
1750 | Source_Typ : Entity_Id := Empty) | |
1751 | is | |
1752 | begin | |
1753 | Apply_Selected_Length_Checks | |
1754 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
1755 | end Apply_Length_Check; | |
1756 | ||
7aafae1c | 1757 | --------------------------- |
1758 | -- Apply_Predicate_Check -- | |
1759 | --------------------------- | |
1760 | ||
1761 | procedure Apply_Predicate_Check (N : Node_Id; Typ : Entity_Id) is | |
1762 | begin | |
701d57a4 | 1763 | if Present (Predicate_Function (Typ)) then |
7aafae1c | 1764 | Insert_Action (N, |
1765 | Make_Predicate_Check (Typ, Duplicate_Subexpr (N))); | |
1766 | end if; | |
1767 | end Apply_Predicate_Check; | |
1768 | ||
ee6ba406 | 1769 | ----------------------- |
1770 | -- Apply_Range_Check -- | |
1771 | ----------------------- | |
1772 | ||
1773 | procedure Apply_Range_Check | |
1774 | (Ck_Node : Node_Id; | |
1775 | Target_Typ : Entity_Id; | |
1776 | Source_Typ : Entity_Id := Empty) | |
1777 | is | |
1778 | begin | |
1779 | Apply_Selected_Range_Checks | |
1780 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
1781 | end Apply_Range_Check; | |
1782 | ||
1783 | ------------------------------ | |
1784 | -- Apply_Scalar_Range_Check -- | |
1785 | ------------------------------ | |
1786 | ||
feff2f05 | 1787 | -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag |
1788 | -- off if it is already set on. | |
ee6ba406 | 1789 | |
1790 | procedure Apply_Scalar_Range_Check | |
1791 | (Expr : Node_Id; | |
1792 | Target_Typ : Entity_Id; | |
1793 | Source_Typ : Entity_Id := Empty; | |
1794 | Fixed_Int : Boolean := False) | |
1795 | is | |
1796 | Parnt : constant Node_Id := Parent (Expr); | |
1797 | S_Typ : Entity_Id; | |
1798 | Arr : Node_Id := Empty; -- initialize to prevent warning | |
1799 | Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning | |
1800 | OK : Boolean; | |
1801 | ||
1802 | Is_Subscr_Ref : Boolean; | |
1803 | -- Set true if Expr is a subscript | |
1804 | ||
1805 | Is_Unconstrained_Subscr_Ref : Boolean; | |
1806 | -- Set true if Expr is a subscript of an unconstrained array. In this | |
1807 | -- case we do not attempt to do an analysis of the value against the | |
1808 | -- range of the subscript, since we don't know the actual subtype. | |
1809 | ||
1810 | Int_Real : Boolean; | |
feff2f05 | 1811 | -- Set to True if Expr should be regarded as a real value even though |
1812 | -- the type of Expr might be discrete. | |
ee6ba406 | 1813 | |
1814 | procedure Bad_Value; | |
1815 | -- Procedure called if value is determined to be out of range | |
1816 | ||
9dfe12ae | 1817 | --------------- |
1818 | -- Bad_Value -- | |
1819 | --------------- | |
1820 | ||
ee6ba406 | 1821 | procedure Bad_Value is |
1822 | begin | |
1823 | Apply_Compile_Time_Constraint_Error | |
f15731c4 | 1824 | (Expr, "value not in range of}?", CE_Range_Check_Failed, |
ee6ba406 | 1825 | Ent => Target_Typ, |
1826 | Typ => Target_Typ); | |
1827 | end Bad_Value; | |
1828 | ||
9dfe12ae | 1829 | -- Start of processing for Apply_Scalar_Range_Check |
1830 | ||
ee6ba406 | 1831 | begin |
2af58f67 | 1832 | -- Return if check obviously not needed |
ee6ba406 | 1833 | |
2af58f67 | 1834 | if |
1835 | -- Not needed inside generic | |
ee6ba406 | 1836 | |
2af58f67 | 1837 | Inside_A_Generic |
1838 | ||
1839 | -- Not needed if previous error | |
1840 | ||
1841 | or else Target_Typ = Any_Type | |
1842 | or else Nkind (Expr) = N_Error | |
1843 | ||
1844 | -- Not needed for non-scalar type | |
1845 | ||
1846 | or else not Is_Scalar_Type (Target_Typ) | |
1847 | ||
1848 | -- Not needed if we know node raises CE already | |
1849 | ||
1850 | or else Raises_Constraint_Error (Expr) | |
ee6ba406 | 1851 | then |
1852 | return; | |
1853 | end if; | |
1854 | ||
1855 | -- Now, see if checks are suppressed | |
1856 | ||
1857 | Is_Subscr_Ref := | |
1858 | Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component; | |
1859 | ||
1860 | if Is_Subscr_Ref then | |
1861 | Arr := Prefix (Parnt); | |
1862 | Arr_Typ := Get_Actual_Subtype_If_Available (Arr); | |
1863 | end if; | |
1864 | ||
1865 | if not Do_Range_Check (Expr) then | |
1866 | ||
1867 | -- Subscript reference. Check for Index_Checks suppressed | |
1868 | ||
1869 | if Is_Subscr_Ref then | |
1870 | ||
1871 | -- Check array type and its base type | |
1872 | ||
1873 | if Index_Checks_Suppressed (Arr_Typ) | |
9dfe12ae | 1874 | or else Index_Checks_Suppressed (Base_Type (Arr_Typ)) |
ee6ba406 | 1875 | then |
1876 | return; | |
1877 | ||
1878 | -- Check array itself if it is an entity name | |
1879 | ||
1880 | elsif Is_Entity_Name (Arr) | |
9dfe12ae | 1881 | and then Index_Checks_Suppressed (Entity (Arr)) |
ee6ba406 | 1882 | then |
1883 | return; | |
1884 | ||
1885 | -- Check expression itself if it is an entity name | |
1886 | ||
1887 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 1888 | and then Index_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 1889 | then |
1890 | return; | |
1891 | end if; | |
1892 | ||
1893 | -- All other cases, check for Range_Checks suppressed | |
1894 | ||
1895 | else | |
1896 | -- Check target type and its base type | |
1897 | ||
1898 | if Range_Checks_Suppressed (Target_Typ) | |
9dfe12ae | 1899 | or else Range_Checks_Suppressed (Base_Type (Target_Typ)) |
ee6ba406 | 1900 | then |
1901 | return; | |
1902 | ||
1903 | -- Check expression itself if it is an entity name | |
1904 | ||
1905 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 1906 | and then Range_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 1907 | then |
1908 | return; | |
1909 | ||
feff2f05 | 1910 | -- If Expr is part of an assignment statement, then check left |
1911 | -- side of assignment if it is an entity name. | |
ee6ba406 | 1912 | |
1913 | elsif Nkind (Parnt) = N_Assignment_Statement | |
1914 | and then Is_Entity_Name (Name (Parnt)) | |
9dfe12ae | 1915 | and then Range_Checks_Suppressed (Entity (Name (Parnt))) |
ee6ba406 | 1916 | then |
1917 | return; | |
1918 | end if; | |
1919 | end if; | |
1920 | end if; | |
1921 | ||
9dfe12ae | 1922 | -- Do not set range checks if they are killed |
1923 | ||
1924 | if Nkind (Expr) = N_Unchecked_Type_Conversion | |
1925 | and then Kill_Range_Check (Expr) | |
1926 | then | |
1927 | return; | |
1928 | end if; | |
1929 | ||
1930 | -- Do not set range checks for any values from System.Scalar_Values | |
1931 | -- since the whole idea of such values is to avoid checking them! | |
1932 | ||
1933 | if Is_Entity_Name (Expr) | |
1934 | and then Is_RTU (Scope (Entity (Expr)), System_Scalar_Values) | |
1935 | then | |
1936 | return; | |
1937 | end if; | |
1938 | ||
ee6ba406 | 1939 | -- Now see if we need a check |
1940 | ||
1941 | if No (Source_Typ) then | |
1942 | S_Typ := Etype (Expr); | |
1943 | else | |
1944 | S_Typ := Source_Typ; | |
1945 | end if; | |
1946 | ||
1947 | if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then | |
1948 | return; | |
1949 | end if; | |
1950 | ||
1951 | Is_Unconstrained_Subscr_Ref := | |
1952 | Is_Subscr_Ref and then not Is_Constrained (Arr_Typ); | |
1953 | ||
feff2f05 | 1954 | -- Always do a range check if the source type includes infinities and |
1955 | -- the target type does not include infinities. We do not do this if | |
1956 | -- range checks are killed. | |
ee6ba406 | 1957 | |
1958 | if Is_Floating_Point_Type (S_Typ) | |
1959 | and then Has_Infinities (S_Typ) | |
1960 | and then not Has_Infinities (Target_Typ) | |
1961 | then | |
1962 | Enable_Range_Check (Expr); | |
1963 | end if; | |
1964 | ||
feff2f05 | 1965 | -- Return if we know expression is definitely in the range of the target |
1966 | -- type as determined by Determine_Range. Right now we only do this for | |
1967 | -- discrete types, and not fixed-point or floating-point types. | |
ee6ba406 | 1968 | |
f2a06be9 | 1969 | -- The additional less-precise tests below catch these cases |
ee6ba406 | 1970 | |
feff2f05 | 1971 | -- Note: skip this if we are given a source_typ, since the point of |
1972 | -- supplying a Source_Typ is to stop us looking at the expression. | |
1973 | -- We could sharpen this test to be out parameters only ??? | |
ee6ba406 | 1974 | |
1975 | if Is_Discrete_Type (Target_Typ) | |
1976 | and then Is_Discrete_Type (Etype (Expr)) | |
1977 | and then not Is_Unconstrained_Subscr_Ref | |
1978 | and then No (Source_Typ) | |
1979 | then | |
1980 | declare | |
1981 | Tlo : constant Node_Id := Type_Low_Bound (Target_Typ); | |
1982 | Thi : constant Node_Id := Type_High_Bound (Target_Typ); | |
1983 | Lo : Uint; | |
1984 | Hi : Uint; | |
1985 | ||
1986 | begin | |
1987 | if Compile_Time_Known_Value (Tlo) | |
1988 | and then Compile_Time_Known_Value (Thi) | |
1989 | then | |
9dfe12ae | 1990 | declare |
1991 | Lov : constant Uint := Expr_Value (Tlo); | |
1992 | Hiv : constant Uint := Expr_Value (Thi); | |
ee6ba406 | 1993 | |
9dfe12ae | 1994 | begin |
1995 | -- If range is null, we for sure have a constraint error | |
1996 | -- (we don't even need to look at the value involved, | |
1997 | -- since all possible values will raise CE). | |
1998 | ||
1999 | if Lov > Hiv then | |
2000 | Bad_Value; | |
2001 | return; | |
2002 | end if; | |
2003 | ||
2004 | -- Otherwise determine range of value | |
2005 | ||
9c486805 | 2006 | Determine_Range (Expr, OK, Lo, Hi, Assume_Valid => True); |
9dfe12ae | 2007 | |
2008 | if OK then | |
2009 | ||
2010 | -- If definitely in range, all OK | |
ee6ba406 | 2011 | |
ee6ba406 | 2012 | if Lo >= Lov and then Hi <= Hiv then |
2013 | return; | |
2014 | ||
9dfe12ae | 2015 | -- If definitely not in range, warn |
2016 | ||
ee6ba406 | 2017 | elsif Lov > Hi or else Hiv < Lo then |
2018 | Bad_Value; | |
2019 | return; | |
9dfe12ae | 2020 | |
2021 | -- Otherwise we don't know | |
2022 | ||
2023 | else | |
2024 | null; | |
ee6ba406 | 2025 | end if; |
9dfe12ae | 2026 | end if; |
2027 | end; | |
ee6ba406 | 2028 | end if; |
2029 | end; | |
2030 | end if; | |
2031 | ||
2032 | Int_Real := | |
2033 | Is_Floating_Point_Type (S_Typ) | |
2034 | or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int); | |
2035 | ||
2036 | -- Check if we can determine at compile time whether Expr is in the | |
9dfe12ae | 2037 | -- range of the target type. Note that if S_Typ is within the bounds |
2038 | -- of Target_Typ then this must be the case. This check is meaningful | |
2039 | -- only if this is not a conversion between integer and real types. | |
ee6ba406 | 2040 | |
2041 | if not Is_Unconstrained_Subscr_Ref | |
2042 | and then | |
2043 | Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ) | |
2044 | and then | |
7a1dabb3 | 2045 | (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int) |
ee6ba406 | 2046 | or else |
9c486805 | 2047 | Is_In_Range (Expr, Target_Typ, |
2048 | Assume_Valid => True, | |
2049 | Fixed_Int => Fixed_Int, | |
2050 | Int_Real => Int_Real)) | |
ee6ba406 | 2051 | then |
2052 | return; | |
2053 | ||
9c486805 | 2054 | elsif Is_Out_Of_Range (Expr, Target_Typ, |
2055 | Assume_Valid => True, | |
2056 | Fixed_Int => Fixed_Int, | |
2057 | Int_Real => Int_Real) | |
2058 | then | |
ee6ba406 | 2059 | Bad_Value; |
2060 | return; | |
2061 | ||
feff2f05 | 2062 | -- In the floating-point case, we only do range checks if the type is |
2063 | -- constrained. We definitely do NOT want range checks for unconstrained | |
2064 | -- types, since we want to have infinities | |
ee6ba406 | 2065 | |
9dfe12ae | 2066 | elsif Is_Floating_Point_Type (S_Typ) then |
2067 | if Is_Constrained (S_Typ) then | |
2068 | Enable_Range_Check (Expr); | |
2069 | end if; | |
ee6ba406 | 2070 | |
9dfe12ae | 2071 | -- For all other cases we enable a range check unconditionally |
ee6ba406 | 2072 | |
2073 | else | |
2074 | Enable_Range_Check (Expr); | |
2075 | return; | |
2076 | end if; | |
ee6ba406 | 2077 | end Apply_Scalar_Range_Check; |
2078 | ||
2079 | ---------------------------------- | |
2080 | -- Apply_Selected_Length_Checks -- | |
2081 | ---------------------------------- | |
2082 | ||
2083 | procedure Apply_Selected_Length_Checks | |
2084 | (Ck_Node : Node_Id; | |
2085 | Target_Typ : Entity_Id; | |
2086 | Source_Typ : Entity_Id; | |
2087 | Do_Static : Boolean) | |
2088 | is | |
2089 | Cond : Node_Id; | |
2090 | R_Result : Check_Result; | |
2091 | R_Cno : Node_Id; | |
2092 | ||
2093 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
2094 | Checks_On : constant Boolean := | |
2095 | (not Index_Checks_Suppressed (Target_Typ)) | |
2096 | or else | |
2097 | (not Length_Checks_Suppressed (Target_Typ)); | |
2098 | ||
2099 | begin | |
f15731c4 | 2100 | if not Expander_Active then |
ee6ba406 | 2101 | return; |
2102 | end if; | |
2103 | ||
2104 | R_Result := | |
2105 | Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
2106 | ||
2107 | for J in 1 .. 2 loop | |
ee6ba406 | 2108 | R_Cno := R_Result (J); |
2109 | exit when No (R_Cno); | |
2110 | ||
2111 | -- A length check may mention an Itype which is attached to a | |
2112 | -- subsequent node. At the top level in a package this can cause | |
2113 | -- an order-of-elaboration problem, so we make sure that the itype | |
2114 | -- is referenced now. | |
2115 | ||
2116 | if Ekind (Current_Scope) = E_Package | |
2117 | and then Is_Compilation_Unit (Current_Scope) | |
2118 | then | |
2119 | Ensure_Defined (Target_Typ, Ck_Node); | |
2120 | ||
2121 | if Present (Source_Typ) then | |
2122 | Ensure_Defined (Source_Typ, Ck_Node); | |
2123 | ||
2124 | elsif Is_Itype (Etype (Ck_Node)) then | |
2125 | Ensure_Defined (Etype (Ck_Node), Ck_Node); | |
2126 | end if; | |
2127 | end if; | |
2128 | ||
feff2f05 | 2129 | -- If the item is a conditional raise of constraint error, then have |
2130 | -- a look at what check is being performed and ??? | |
ee6ba406 | 2131 | |
2132 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
2133 | and then Present (Condition (R_Cno)) | |
2134 | then | |
2135 | Cond := Condition (R_Cno); | |
2136 | ||
0577b0b1 | 2137 | -- Case where node does not now have a dynamic check |
ee6ba406 | 2138 | |
0577b0b1 | 2139 | if not Has_Dynamic_Length_Check (Ck_Node) then |
2140 | ||
2141 | -- If checks are on, just insert the check | |
2142 | ||
2143 | if Checks_On then | |
2144 | Insert_Action (Ck_Node, R_Cno); | |
2145 | ||
2146 | if not Do_Static then | |
2147 | Set_Has_Dynamic_Length_Check (Ck_Node); | |
2148 | end if; | |
2149 | ||
2150 | -- If checks are off, then analyze the length check after | |
2151 | -- temporarily attaching it to the tree in case the relevant | |
6fb3c314 | 2152 | -- condition can be evaluated at compile time. We still want a |
0577b0b1 | 2153 | -- compile time warning in this case. |
2154 | ||
2155 | else | |
2156 | Set_Parent (R_Cno, Ck_Node); | |
2157 | Analyze (R_Cno); | |
ee6ba406 | 2158 | end if; |
ee6ba406 | 2159 | end if; |
2160 | ||
2161 | -- Output a warning if the condition is known to be True | |
2162 | ||
2163 | if Is_Entity_Name (Cond) | |
2164 | and then Entity (Cond) = Standard_True | |
2165 | then | |
2166 | Apply_Compile_Time_Constraint_Error | |
2167 | (Ck_Node, "wrong length for array of}?", | |
f15731c4 | 2168 | CE_Length_Check_Failed, |
ee6ba406 | 2169 | Ent => Target_Typ, |
2170 | Typ => Target_Typ); | |
2171 | ||
2172 | -- If we were only doing a static check, or if checks are not | |
2173 | -- on, then we want to delete the check, since it is not needed. | |
2174 | -- We do this by replacing the if statement by a null statement | |
2175 | ||
2176 | elsif Do_Static or else not Checks_On then | |
00c403ee | 2177 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 2178 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
2179 | end if; | |
2180 | ||
2181 | else | |
2182 | Install_Static_Check (R_Cno, Loc); | |
2183 | end if; | |
ee6ba406 | 2184 | end loop; |
ee6ba406 | 2185 | end Apply_Selected_Length_Checks; |
2186 | ||
2187 | --------------------------------- | |
2188 | -- Apply_Selected_Range_Checks -- | |
2189 | --------------------------------- | |
2190 | ||
2191 | procedure Apply_Selected_Range_Checks | |
2192 | (Ck_Node : Node_Id; | |
2193 | Target_Typ : Entity_Id; | |
2194 | Source_Typ : Entity_Id; | |
2195 | Do_Static : Boolean) | |
2196 | is | |
2197 | Cond : Node_Id; | |
2198 | R_Result : Check_Result; | |
2199 | R_Cno : Node_Id; | |
2200 | ||
2201 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
2202 | Checks_On : constant Boolean := | |
2203 | (not Index_Checks_Suppressed (Target_Typ)) | |
2204 | or else | |
2205 | (not Range_Checks_Suppressed (Target_Typ)); | |
2206 | ||
2207 | begin | |
2208 | if not Expander_Active or else not Checks_On then | |
2209 | return; | |
2210 | end if; | |
2211 | ||
2212 | R_Result := | |
2213 | Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
2214 | ||
2215 | for J in 1 .. 2 loop | |
2216 | ||
2217 | R_Cno := R_Result (J); | |
2218 | exit when No (R_Cno); | |
2219 | ||
feff2f05 | 2220 | -- If the item is a conditional raise of constraint error, then have |
2221 | -- a look at what check is being performed and ??? | |
ee6ba406 | 2222 | |
2223 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
2224 | and then Present (Condition (R_Cno)) | |
2225 | then | |
2226 | Cond := Condition (R_Cno); | |
2227 | ||
2228 | if not Has_Dynamic_Range_Check (Ck_Node) then | |
2229 | Insert_Action (Ck_Node, R_Cno); | |
2230 | ||
2231 | if not Do_Static then | |
2232 | Set_Has_Dynamic_Range_Check (Ck_Node); | |
2233 | end if; | |
2234 | end if; | |
2235 | ||
2236 | -- Output a warning if the condition is known to be True | |
2237 | ||
2238 | if Is_Entity_Name (Cond) | |
2239 | and then Entity (Cond) = Standard_True | |
2240 | then | |
feff2f05 | 2241 | -- Since an N_Range is technically not an expression, we have |
2242 | -- to set one of the bounds to C_E and then just flag the | |
2243 | -- N_Range. The warning message will point to the lower bound | |
2244 | -- and complain about a range, which seems OK. | |
ee6ba406 | 2245 | |
2246 | if Nkind (Ck_Node) = N_Range then | |
2247 | Apply_Compile_Time_Constraint_Error | |
2248 | (Low_Bound (Ck_Node), "static range out of bounds of}?", | |
f15731c4 | 2249 | CE_Range_Check_Failed, |
ee6ba406 | 2250 | Ent => Target_Typ, |
2251 | Typ => Target_Typ); | |
2252 | ||
2253 | Set_Raises_Constraint_Error (Ck_Node); | |
2254 | ||
2255 | else | |
2256 | Apply_Compile_Time_Constraint_Error | |
2257 | (Ck_Node, "static value out of range of}?", | |
f15731c4 | 2258 | CE_Range_Check_Failed, |
ee6ba406 | 2259 | Ent => Target_Typ, |
2260 | Typ => Target_Typ); | |
2261 | end if; | |
2262 | ||
2263 | -- If we were only doing a static check, or if checks are not | |
2264 | -- on, then we want to delete the check, since it is not needed. | |
2265 | -- We do this by replacing the if statement by a null statement | |
2266 | ||
2267 | elsif Do_Static or else not Checks_On then | |
00c403ee | 2268 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 2269 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
2270 | end if; | |
2271 | ||
2272 | else | |
2273 | Install_Static_Check (R_Cno, Loc); | |
2274 | end if; | |
ee6ba406 | 2275 | end loop; |
ee6ba406 | 2276 | end Apply_Selected_Range_Checks; |
2277 | ||
2278 | ------------------------------- | |
2279 | -- Apply_Static_Length_Check -- | |
2280 | ------------------------------- | |
2281 | ||
2282 | procedure Apply_Static_Length_Check | |
2283 | (Expr : Node_Id; | |
2284 | Target_Typ : Entity_Id; | |
2285 | Source_Typ : Entity_Id := Empty) | |
2286 | is | |
2287 | begin | |
2288 | Apply_Selected_Length_Checks | |
2289 | (Expr, Target_Typ, Source_Typ, Do_Static => True); | |
2290 | end Apply_Static_Length_Check; | |
2291 | ||
2292 | ------------------------------------- | |
2293 | -- Apply_Subscript_Validity_Checks -- | |
2294 | ------------------------------------- | |
2295 | ||
2296 | procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is | |
2297 | Sub : Node_Id; | |
2298 | ||
2299 | begin | |
2300 | pragma Assert (Nkind (Expr) = N_Indexed_Component); | |
2301 | ||
2302 | -- Loop through subscripts | |
2303 | ||
2304 | Sub := First (Expressions (Expr)); | |
2305 | while Present (Sub) loop | |
2306 | ||
feff2f05 | 2307 | -- Check one subscript. Note that we do not worry about enumeration |
2308 | -- type with holes, since we will convert the value to a Pos value | |
2309 | -- for the subscript, and that convert will do the necessary validity | |
2310 | -- check. | |
ee6ba406 | 2311 | |
2312 | Ensure_Valid (Sub, Holes_OK => True); | |
2313 | ||
2314 | -- Move to next subscript | |
2315 | ||
2316 | Sub := Next (Sub); | |
2317 | end loop; | |
2318 | end Apply_Subscript_Validity_Checks; | |
2319 | ||
2320 | ---------------------------------- | |
2321 | -- Apply_Type_Conversion_Checks -- | |
2322 | ---------------------------------- | |
2323 | ||
2324 | procedure Apply_Type_Conversion_Checks (N : Node_Id) is | |
2325 | Target_Type : constant Entity_Id := Etype (N); | |
2326 | Target_Base : constant Entity_Id := Base_Type (Target_Type); | |
9dfe12ae | 2327 | Expr : constant Node_Id := Expression (N); |
2328 | Expr_Type : constant Entity_Id := Etype (Expr); | |
ee6ba406 | 2329 | |
2330 | begin | |
2331 | if Inside_A_Generic then | |
2332 | return; | |
2333 | ||
f15731c4 | 2334 | -- Skip these checks if serious errors detected, there are some nasty |
ee6ba406 | 2335 | -- situations of incomplete trees that blow things up. |
2336 | ||
f15731c4 | 2337 | elsif Serious_Errors_Detected > 0 then |
ee6ba406 | 2338 | return; |
2339 | ||
feff2f05 | 2340 | -- Scalar type conversions of the form Target_Type (Expr) require a |
2341 | -- range check if we cannot be sure that Expr is in the base type of | |
2342 | -- Target_Typ and also that Expr is in the range of Target_Typ. These | |
2343 | -- are not quite the same condition from an implementation point of | |
2344 | -- view, but clearly the second includes the first. | |
ee6ba406 | 2345 | |
2346 | elsif Is_Scalar_Type (Target_Type) then | |
2347 | declare | |
2348 | Conv_OK : constant Boolean := Conversion_OK (N); | |
feff2f05 | 2349 | -- If the Conversion_OK flag on the type conversion is set and no |
2350 | -- floating point type is involved in the type conversion then | |
2351 | -- fixed point values must be read as integral values. | |
ee6ba406 | 2352 | |
5329ca64 | 2353 | Float_To_Int : constant Boolean := |
2354 | Is_Floating_Point_Type (Expr_Type) | |
2355 | and then Is_Integer_Type (Target_Type); | |
2356 | ||
ee6ba406 | 2357 | begin |
ee6ba406 | 2358 | if not Overflow_Checks_Suppressed (Target_Base) |
e254d721 | 2359 | and then not |
7a1dabb3 | 2360 | In_Subrange_Of (Expr_Type, Target_Base, Fixed_Int => Conv_OK) |
5329ca64 | 2361 | and then not Float_To_Int |
ee6ba406 | 2362 | then |
00c403ee | 2363 | Activate_Overflow_Check (N); |
ee6ba406 | 2364 | end if; |
2365 | ||
2366 | if not Range_Checks_Suppressed (Target_Type) | |
2367 | and then not Range_Checks_Suppressed (Expr_Type) | |
2368 | then | |
5329ca64 | 2369 | if Float_To_Int then |
2370 | Apply_Float_Conversion_Check (Expr, Target_Type); | |
2371 | else | |
2372 | Apply_Scalar_Range_Check | |
2373 | (Expr, Target_Type, Fixed_Int => Conv_OK); | |
2374 | end if; | |
ee6ba406 | 2375 | end if; |
2376 | end; | |
2377 | ||
2378 | elsif Comes_From_Source (N) | |
f40f9731 | 2379 | and then not Discriminant_Checks_Suppressed (Target_Type) |
ee6ba406 | 2380 | and then Is_Record_Type (Target_Type) |
2381 | and then Is_Derived_Type (Target_Type) | |
2382 | and then not Is_Tagged_Type (Target_Type) | |
2383 | and then not Is_Constrained (Target_Type) | |
9dfe12ae | 2384 | and then Present (Stored_Constraint (Target_Type)) |
ee6ba406 | 2385 | then |
9dfe12ae | 2386 | -- An unconstrained derived type may have inherited discriminant |
2387 | -- Build an actual discriminant constraint list using the stored | |
ee6ba406 | 2388 | -- constraint, to verify that the expression of the parent type |
2389 | -- satisfies the constraints imposed by the (unconstrained!) | |
2390 | -- derived type. This applies to value conversions, not to view | |
2391 | -- conversions of tagged types. | |
2392 | ||
2393 | declare | |
9dfe12ae | 2394 | Loc : constant Source_Ptr := Sloc (N); |
2395 | Cond : Node_Id; | |
2396 | Constraint : Elmt_Id; | |
2397 | Discr_Value : Node_Id; | |
2398 | Discr : Entity_Id; | |
2399 | ||
2400 | New_Constraints : constant Elist_Id := New_Elmt_List; | |
2401 | Old_Constraints : constant Elist_Id := | |
2402 | Discriminant_Constraint (Expr_Type); | |
ee6ba406 | 2403 | |
2404 | begin | |
9dfe12ae | 2405 | Constraint := First_Elmt (Stored_Constraint (Target_Type)); |
ee6ba406 | 2406 | while Present (Constraint) loop |
2407 | Discr_Value := Node (Constraint); | |
2408 | ||
2409 | if Is_Entity_Name (Discr_Value) | |
2410 | and then Ekind (Entity (Discr_Value)) = E_Discriminant | |
2411 | then | |
2412 | Discr := Corresponding_Discriminant (Entity (Discr_Value)); | |
2413 | ||
2414 | if Present (Discr) | |
2415 | and then Scope (Discr) = Base_Type (Expr_Type) | |
2416 | then | |
2417 | -- Parent is constrained by new discriminant. Obtain | |
feff2f05 | 2418 | -- Value of original discriminant in expression. If the |
2419 | -- new discriminant has been used to constrain more than | |
2420 | -- one of the stored discriminants, this will provide the | |
2421 | -- required consistency check. | |
ee6ba406 | 2422 | |
55868293 | 2423 | Append_Elmt |
2424 | (Make_Selected_Component (Loc, | |
2425 | Prefix => | |
9dfe12ae | 2426 | Duplicate_Subexpr_No_Checks |
2427 | (Expr, Name_Req => True), | |
ee6ba406 | 2428 | Selector_Name => |
2429 | Make_Identifier (Loc, Chars (Discr))), | |
55868293 | 2430 | New_Constraints); |
ee6ba406 | 2431 | |
2432 | else | |
2433 | -- Discriminant of more remote ancestor ??? | |
2434 | ||
2435 | return; | |
2436 | end if; | |
2437 | ||
feff2f05 | 2438 | -- Derived type definition has an explicit value for this |
2439 | -- stored discriminant. | |
ee6ba406 | 2440 | |
2441 | else | |
2442 | Append_Elmt | |
9dfe12ae | 2443 | (Duplicate_Subexpr_No_Checks (Discr_Value), |
2444 | New_Constraints); | |
ee6ba406 | 2445 | end if; |
2446 | ||
2447 | Next_Elmt (Constraint); | |
2448 | end loop; | |
2449 | ||
2450 | -- Use the unconstrained expression type to retrieve the | |
2451 | -- discriminants of the parent, and apply momentarily the | |
2452 | -- discriminant constraint synthesized above. | |
2453 | ||
2454 | Set_Discriminant_Constraint (Expr_Type, New_Constraints); | |
2455 | Cond := Build_Discriminant_Checks (Expr, Expr_Type); | |
2456 | Set_Discriminant_Constraint (Expr_Type, Old_Constraints); | |
2457 | ||
2458 | Insert_Action (N, | |
f15731c4 | 2459 | Make_Raise_Constraint_Error (Loc, |
2460 | Condition => Cond, | |
2461 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 2462 | end; |
2463 | ||
feff2f05 | 2464 | -- For arrays, conversions are applied during expansion, to take into |
2465 | -- accounts changes of representation. The checks become range checks on | |
2466 | -- the base type or length checks on the subtype, depending on whether | |
2467 | -- the target type is unconstrained or constrained. | |
ee6ba406 | 2468 | |
2469 | else | |
2470 | null; | |
2471 | end if; | |
ee6ba406 | 2472 | end Apply_Type_Conversion_Checks; |
2473 | ||
2474 | ---------------------------------------------- | |
2475 | -- Apply_Universal_Integer_Attribute_Checks -- | |
2476 | ---------------------------------------------- | |
2477 | ||
2478 | procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is | |
2479 | Loc : constant Source_Ptr := Sloc (N); | |
2480 | Typ : constant Entity_Id := Etype (N); | |
2481 | ||
2482 | begin | |
2483 | if Inside_A_Generic then | |
2484 | return; | |
2485 | ||
2486 | -- Nothing to do if checks are suppressed | |
2487 | ||
2488 | elsif Range_Checks_Suppressed (Typ) | |
2489 | and then Overflow_Checks_Suppressed (Typ) | |
2490 | then | |
2491 | return; | |
2492 | ||
2493 | -- Nothing to do if the attribute does not come from source. The | |
2494 | -- internal attributes we generate of this type do not need checks, | |
2495 | -- and furthermore the attempt to check them causes some circular | |
2496 | -- elaboration orders when dealing with packed types. | |
2497 | ||
2498 | elsif not Comes_From_Source (N) then | |
2499 | return; | |
2500 | ||
9dfe12ae | 2501 | -- If the prefix is a selected component that depends on a discriminant |
2502 | -- the check may improperly expose a discriminant instead of using | |
2503 | -- the bounds of the object itself. Set the type of the attribute to | |
2504 | -- the base type of the context, so that a check will be imposed when | |
2505 | -- needed (e.g. if the node appears as an index). | |
2506 | ||
2507 | elsif Nkind (Prefix (N)) = N_Selected_Component | |
2508 | and then Ekind (Typ) = E_Signed_Integer_Subtype | |
2509 | and then Depends_On_Discriminant (Scalar_Range (Typ)) | |
2510 | then | |
2511 | Set_Etype (N, Base_Type (Typ)); | |
2512 | ||
feff2f05 | 2513 | -- Otherwise, replace the attribute node with a type conversion node |
2514 | -- whose expression is the attribute, retyped to universal integer, and | |
2515 | -- whose subtype mark is the target type. The call to analyze this | |
2516 | -- conversion will set range and overflow checks as required for proper | |
2517 | -- detection of an out of range value. | |
ee6ba406 | 2518 | |
2519 | else | |
2520 | Set_Etype (N, Universal_Integer); | |
2521 | Set_Analyzed (N, True); | |
2522 | ||
2523 | Rewrite (N, | |
2524 | Make_Type_Conversion (Loc, | |
2525 | Subtype_Mark => New_Occurrence_Of (Typ, Loc), | |
2526 | Expression => Relocate_Node (N))); | |
2527 | ||
2528 | Analyze_And_Resolve (N, Typ); | |
2529 | return; | |
2530 | end if; | |
ee6ba406 | 2531 | end Apply_Universal_Integer_Attribute_Checks; |
2532 | ||
2533 | ------------------------------- | |
2534 | -- Build_Discriminant_Checks -- | |
2535 | ------------------------------- | |
2536 | ||
2537 | function Build_Discriminant_Checks | |
2538 | (N : Node_Id; | |
314a23b6 | 2539 | T_Typ : Entity_Id) return Node_Id |
ee6ba406 | 2540 | is |
2541 | Loc : constant Source_Ptr := Sloc (N); | |
2542 | Cond : Node_Id; | |
2543 | Disc : Elmt_Id; | |
2544 | Disc_Ent : Entity_Id; | |
9dfe12ae | 2545 | Dref : Node_Id; |
ee6ba406 | 2546 | Dval : Node_Id; |
2547 | ||
84d0d4a5 | 2548 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id; |
2549 | ||
2550 | ---------------------------------- | |
2551 | -- Aggregate_Discriminant_Value -- | |
2552 | ---------------------------------- | |
2553 | ||
2554 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id is | |
2555 | Assoc : Node_Id; | |
2556 | ||
2557 | begin | |
feff2f05 | 2558 | -- The aggregate has been normalized with named associations. We use |
2559 | -- the Chars field to locate the discriminant to take into account | |
2560 | -- discriminants in derived types, which carry the same name as those | |
2561 | -- in the parent. | |
84d0d4a5 | 2562 | |
2563 | Assoc := First (Component_Associations (N)); | |
2564 | while Present (Assoc) loop | |
2565 | if Chars (First (Choices (Assoc))) = Chars (Disc) then | |
2566 | return Expression (Assoc); | |
2567 | else | |
2568 | Next (Assoc); | |
2569 | end if; | |
2570 | end loop; | |
2571 | ||
2572 | -- Discriminant must have been found in the loop above | |
2573 | ||
2574 | raise Program_Error; | |
2575 | end Aggregate_Discriminant_Val; | |
2576 | ||
2577 | -- Start of processing for Build_Discriminant_Checks | |
2578 | ||
ee6ba406 | 2579 | begin |
84d0d4a5 | 2580 | -- Loop through discriminants evolving the condition |
2581 | ||
ee6ba406 | 2582 | Cond := Empty; |
2583 | Disc := First_Elmt (Discriminant_Constraint (T_Typ)); | |
2584 | ||
9dfe12ae | 2585 | -- For a fully private type, use the discriminants of the parent type |
ee6ba406 | 2586 | |
2587 | if Is_Private_Type (T_Typ) | |
2588 | and then No (Full_View (T_Typ)) | |
2589 | then | |
2590 | Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ))); | |
2591 | else | |
2592 | Disc_Ent := First_Discriminant (T_Typ); | |
2593 | end if; | |
2594 | ||
2595 | while Present (Disc) loop | |
ee6ba406 | 2596 | Dval := Node (Disc); |
2597 | ||
2598 | if Nkind (Dval) = N_Identifier | |
2599 | and then Ekind (Entity (Dval)) = E_Discriminant | |
2600 | then | |
2601 | Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc); | |
2602 | else | |
9dfe12ae | 2603 | Dval := Duplicate_Subexpr_No_Checks (Dval); |
ee6ba406 | 2604 | end if; |
2605 | ||
00f91aef | 2606 | -- If we have an Unchecked_Union node, we can infer the discriminants |
2607 | -- of the node. | |
9dfe12ae | 2608 | |
00f91aef | 2609 | if Is_Unchecked_Union (Base_Type (T_Typ)) then |
2610 | Dref := New_Copy ( | |
2611 | Get_Discriminant_Value ( | |
2612 | First_Discriminant (T_Typ), | |
2613 | T_Typ, | |
2614 | Stored_Constraint (T_Typ))); | |
2615 | ||
84d0d4a5 | 2616 | elsif Nkind (N) = N_Aggregate then |
2617 | Dref := | |
2618 | Duplicate_Subexpr_No_Checks | |
2619 | (Aggregate_Discriminant_Val (Disc_Ent)); | |
2620 | ||
00f91aef | 2621 | else |
2622 | Dref := | |
2623 | Make_Selected_Component (Loc, | |
2624 | Prefix => | |
2625 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), | |
2626 | Selector_Name => | |
2627 | Make_Identifier (Loc, Chars (Disc_Ent))); | |
2628 | ||
2629 | Set_Is_In_Discriminant_Check (Dref); | |
2630 | end if; | |
9dfe12ae | 2631 | |
ee6ba406 | 2632 | Evolve_Or_Else (Cond, |
2633 | Make_Op_Ne (Loc, | |
9dfe12ae | 2634 | Left_Opnd => Dref, |
ee6ba406 | 2635 | Right_Opnd => Dval)); |
2636 | ||
2637 | Next_Elmt (Disc); | |
2638 | Next_Discriminant (Disc_Ent); | |
2639 | end loop; | |
2640 | ||
2641 | return Cond; | |
2642 | end Build_Discriminant_Checks; | |
2643 | ||
13dbf220 | 2644 | ------------------ |
2645 | -- Check_Needed -- | |
2646 | ------------------ | |
2647 | ||
2648 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean is | |
2649 | N : Node_Id; | |
2650 | P : Node_Id; | |
2651 | K : Node_Kind; | |
2652 | L : Node_Id; | |
2653 | R : Node_Id; | |
2654 | ||
2655 | begin | |
2656 | -- Always check if not simple entity | |
2657 | ||
2658 | if Nkind (Nod) not in N_Has_Entity | |
2659 | or else not Comes_From_Source (Nod) | |
2660 | then | |
2661 | return True; | |
2662 | end if; | |
2663 | ||
2664 | -- Look up tree for short circuit | |
2665 | ||
2666 | N := Nod; | |
2667 | loop | |
2668 | P := Parent (N); | |
2669 | K := Nkind (P); | |
2670 | ||
7b17e51b | 2671 | -- Done if out of subexpression (note that we allow generated stuff |
2672 | -- such as itype declarations in this context, to keep the loop going | |
2673 | -- since we may well have generated such stuff in complex situations. | |
2674 | -- Also done if no parent (probably an error condition, but no point | |
2675 | -- in behaving nasty if we find it!) | |
2676 | ||
2677 | if No (P) | |
2678 | or else (K not in N_Subexpr and then Comes_From_Source (P)) | |
2679 | then | |
13dbf220 | 2680 | return True; |
2681 | ||
7b17e51b | 2682 | -- Or/Or Else case, where test is part of the right operand, or is |
2683 | -- part of one of the actions associated with the right operand, and | |
2684 | -- the left operand is an equality test. | |
13dbf220 | 2685 | |
7b17e51b | 2686 | elsif K = N_Op_Or then |
13dbf220 | 2687 | exit when N = Right_Opnd (P) |
2688 | and then Nkind (Left_Opnd (P)) = N_Op_Eq; | |
2689 | ||
7b17e51b | 2690 | elsif K = N_Or_Else then |
2691 | exit when (N = Right_Opnd (P) | |
2692 | or else | |
2693 | (Is_List_Member (N) | |
2694 | and then List_Containing (N) = Actions (P))) | |
2695 | and then Nkind (Left_Opnd (P)) = N_Op_Eq; | |
13dbf220 | 2696 | |
7b17e51b | 2697 | -- Similar test for the And/And then case, where the left operand |
2698 | -- is an inequality test. | |
2699 | ||
2700 | elsif K = N_Op_And then | |
13dbf220 | 2701 | exit when N = Right_Opnd (P) |
38f5559f | 2702 | and then Nkind (Left_Opnd (P)) = N_Op_Ne; |
7b17e51b | 2703 | |
2704 | elsif K = N_And_Then then | |
2705 | exit when (N = Right_Opnd (P) | |
2706 | or else | |
2707 | (Is_List_Member (N) | |
2708 | and then List_Containing (N) = Actions (P))) | |
2709 | and then Nkind (Left_Opnd (P)) = N_Op_Ne; | |
13dbf220 | 2710 | end if; |
2711 | ||
2712 | N := P; | |
2713 | end loop; | |
2714 | ||
2715 | -- If we fall through the loop, then we have a conditional with an | |
2716 | -- appropriate test as its left operand. So test further. | |
2717 | ||
2718 | L := Left_Opnd (P); | |
13dbf220 | 2719 | R := Right_Opnd (L); |
2720 | L := Left_Opnd (L); | |
2721 | ||
2722 | -- Left operand of test must match original variable | |
2723 | ||
2724 | if Nkind (L) not in N_Has_Entity | |
2725 | or else Entity (L) /= Entity (Nod) | |
2726 | then | |
2727 | return True; | |
2728 | end if; | |
2729 | ||
2af58f67 | 2730 | -- Right operand of test must be key value (zero or null) |
13dbf220 | 2731 | |
2732 | case Check is | |
2733 | when Access_Check => | |
2af58f67 | 2734 | if not Known_Null (R) then |
13dbf220 | 2735 | return True; |
2736 | end if; | |
2737 | ||
2738 | when Division_Check => | |
2739 | if not Compile_Time_Known_Value (R) | |
2740 | or else Expr_Value (R) /= Uint_0 | |
2741 | then | |
2742 | return True; | |
2743 | end if; | |
2af58f67 | 2744 | |
2745 | when others => | |
2746 | raise Program_Error; | |
13dbf220 | 2747 | end case; |
2748 | ||
2749 | -- Here we have the optimizable case, warn if not short-circuited | |
2750 | ||
2751 | if K = N_Op_And or else K = N_Op_Or then | |
2752 | case Check is | |
2753 | when Access_Check => | |
2754 | Error_Msg_N | |
2755 | ("Constraint_Error may be raised (access check)?", | |
2756 | Parent (Nod)); | |
2757 | when Division_Check => | |
2758 | Error_Msg_N | |
2759 | ("Constraint_Error may be raised (zero divide)?", | |
2760 | Parent (Nod)); | |
2af58f67 | 2761 | |
2762 | when others => | |
2763 | raise Program_Error; | |
13dbf220 | 2764 | end case; |
2765 | ||
2766 | if K = N_Op_And then | |
e977c0cf | 2767 | Error_Msg_N -- CODEFIX |
2768 | ("use `AND THEN` instead of AND?", P); | |
13dbf220 | 2769 | else |
e977c0cf | 2770 | Error_Msg_N -- CODEFIX |
2771 | ("use `OR ELSE` instead of OR?", P); | |
13dbf220 | 2772 | end if; |
2773 | ||
6fb3c314 | 2774 | -- If not short-circuited, we need the check |
13dbf220 | 2775 | |
2776 | return True; | |
2777 | ||
2778 | -- If short-circuited, we can omit the check | |
2779 | ||
2780 | else | |
2781 | return False; | |
2782 | end if; | |
2783 | end Check_Needed; | |
2784 | ||
ee6ba406 | 2785 | ----------------------------------- |
2786 | -- Check_Valid_Lvalue_Subscripts -- | |
2787 | ----------------------------------- | |
2788 | ||
2789 | procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is | |
2790 | begin | |
2791 | -- Skip this if range checks are suppressed | |
2792 | ||
2793 | if Range_Checks_Suppressed (Etype (Expr)) then | |
2794 | return; | |
2795 | ||
feff2f05 | 2796 | -- Only do this check for expressions that come from source. We assume |
2797 | -- that expander generated assignments explicitly include any necessary | |
2798 | -- checks. Note that this is not just an optimization, it avoids | |
2799 | -- infinite recursions! | |
ee6ba406 | 2800 | |
2801 | elsif not Comes_From_Source (Expr) then | |
2802 | return; | |
2803 | ||
2804 | -- For a selected component, check the prefix | |
2805 | ||
2806 | elsif Nkind (Expr) = N_Selected_Component then | |
2807 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
2808 | return; | |
2809 | ||
2810 | -- Case of indexed component | |
2811 | ||
2812 | elsif Nkind (Expr) = N_Indexed_Component then | |
2813 | Apply_Subscript_Validity_Checks (Expr); | |
2814 | ||
feff2f05 | 2815 | -- Prefix may itself be or contain an indexed component, and these |
2816 | -- subscripts need checking as well. | |
ee6ba406 | 2817 | |
2818 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
2819 | end if; | |
2820 | end Check_Valid_Lvalue_Subscripts; | |
2821 | ||
fa7497e8 | 2822 | ---------------------------------- |
2823 | -- Null_Exclusion_Static_Checks -- | |
2824 | ---------------------------------- | |
2825 | ||
2826 | procedure Null_Exclusion_Static_Checks (N : Node_Id) is | |
0577b0b1 | 2827 | Error_Node : Node_Id; |
2828 | Expr : Node_Id; | |
2829 | Has_Null : constant Boolean := Has_Null_Exclusion (N); | |
2830 | K : constant Node_Kind := Nkind (N); | |
2831 | Typ : Entity_Id; | |
fa7497e8 | 2832 | |
13dbf220 | 2833 | begin |
0577b0b1 | 2834 | pragma Assert |
2835 | (K = N_Component_Declaration | |
2836 | or else K = N_Discriminant_Specification | |
2837 | or else K = N_Function_Specification | |
2838 | or else K = N_Object_Declaration | |
2839 | or else K = N_Parameter_Specification); | |
2840 | ||
2841 | if K = N_Function_Specification then | |
2842 | Typ := Etype (Defining_Entity (N)); | |
2843 | else | |
2844 | Typ := Etype (Defining_Identifier (N)); | |
2845 | end if; | |
fa7497e8 | 2846 | |
13dbf220 | 2847 | case K is |
13dbf220 | 2848 | when N_Component_Declaration => |
2849 | if Present (Access_Definition (Component_Definition (N))) then | |
0577b0b1 | 2850 | Error_Node := Component_Definition (N); |
13dbf220 | 2851 | else |
0577b0b1 | 2852 | Error_Node := Subtype_Indication (Component_Definition (N)); |
13dbf220 | 2853 | end if; |
5329ca64 | 2854 | |
0577b0b1 | 2855 | when N_Discriminant_Specification => |
2856 | Error_Node := Discriminant_Type (N); | |
2857 | ||
2858 | when N_Function_Specification => | |
2859 | Error_Node := Result_Definition (N); | |
2860 | ||
2861 | when N_Object_Declaration => | |
2862 | Error_Node := Object_Definition (N); | |
2863 | ||
2864 | when N_Parameter_Specification => | |
2865 | Error_Node := Parameter_Type (N); | |
2866 | ||
13dbf220 | 2867 | when others => |
2868 | raise Program_Error; | |
2869 | end case; | |
5329ca64 | 2870 | |
0577b0b1 | 2871 | if Has_Null then |
5329ca64 | 2872 | |
0577b0b1 | 2873 | -- Enforce legality rule 3.10 (13): A null exclusion can only be |
2874 | -- applied to an access [sub]type. | |
5329ca64 | 2875 | |
0577b0b1 | 2876 | if not Is_Access_Type (Typ) then |
503f7fd3 | 2877 | Error_Msg_N |
00c403ee | 2878 | ("`NOT NULL` allowed only for an access type", Error_Node); |
5329ca64 | 2879 | |
feff2f05 | 2880 | -- Enforce legality rule RM 3.10(14/1): A null exclusion can only |
0577b0b1 | 2881 | -- be applied to a [sub]type that does not exclude null already. |
2882 | ||
2883 | elsif Can_Never_Be_Null (Typ) | |
d16989f1 | 2884 | and then Comes_From_Source (Typ) |
0577b0b1 | 2885 | then |
503f7fd3 | 2886 | Error_Msg_NE |
00c403ee | 2887 | ("`NOT NULL` not allowed (& already excludes null)", |
2888 | Error_Node, Typ); | |
0577b0b1 | 2889 | end if; |
13dbf220 | 2890 | end if; |
5329ca64 | 2891 | |
cc60bd16 | 2892 | -- Check that null-excluding objects are always initialized, except for |
2893 | -- deferred constants, for which the expression will appear in the full | |
2894 | -- declaration. | |
13dbf220 | 2895 | |
2896 | if K = N_Object_Declaration | |
84d0d4a5 | 2897 | and then No (Expression (N)) |
cc60bd16 | 2898 | and then not Constant_Present (N) |
feff2f05 | 2899 | and then not No_Initialization (N) |
13dbf220 | 2900 | then |
feff2f05 | 2901 | -- Add an expression that assigns null. This node is needed by |
2902 | -- Apply_Compile_Time_Constraint_Error, which will replace this with | |
2903 | -- a Constraint_Error node. | |
13dbf220 | 2904 | |
2905 | Set_Expression (N, Make_Null (Sloc (N))); | |
2906 | Set_Etype (Expression (N), Etype (Defining_Identifier (N))); | |
5329ca64 | 2907 | |
13dbf220 | 2908 | Apply_Compile_Time_Constraint_Error |
2909 | (N => Expression (N), | |
2910 | Msg => "(Ada 2005) null-excluding objects must be initialized?", | |
2911 | Reason => CE_Null_Not_Allowed); | |
2912 | end if; | |
5329ca64 | 2913 | |
cc60bd16 | 2914 | -- Check that a null-excluding component, formal or object is not being |
2915 | -- assigned a null value. Otherwise generate a warning message and | |
2c145f84 | 2916 | -- replace Expression (N) by an N_Constraint_Error node. |
13dbf220 | 2917 | |
0577b0b1 | 2918 | if K /= N_Function_Specification then |
2919 | Expr := Expression (N); | |
5329ca64 | 2920 | |
2af58f67 | 2921 | if Present (Expr) and then Known_Null (Expr) then |
13dbf220 | 2922 | case K is |
0577b0b1 | 2923 | when N_Component_Declaration | |
2924 | N_Discriminant_Specification => | |
7189d17f | 2925 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 2926 | (N => Expr, |
2af58f67 | 2927 | Msg => "(Ada 2005) null not allowed " & |
0577b0b1 | 2928 | "in null-excluding components?", |
2929 | Reason => CE_Null_Not_Allowed); | |
5329ca64 | 2930 | |
0577b0b1 | 2931 | when N_Object_Declaration => |
7189d17f | 2932 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 2933 | (N => Expr, |
2af58f67 | 2934 | Msg => "(Ada 2005) null not allowed " & |
0577b0b1 | 2935 | "in null-excluding objects?", |
2936 | Reason => CE_Null_Not_Allowed); | |
5329ca64 | 2937 | |
0577b0b1 | 2938 | when N_Parameter_Specification => |
7189d17f | 2939 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 2940 | (N => Expr, |
2af58f67 | 2941 | Msg => "(Ada 2005) null not allowed " & |
0577b0b1 | 2942 | "in null-excluding formals?", |
2943 | Reason => CE_Null_Not_Allowed); | |
13dbf220 | 2944 | |
2945 | when others => | |
2946 | null; | |
5329ca64 | 2947 | end case; |
2948 | end if; | |
0577b0b1 | 2949 | end if; |
fa7497e8 | 2950 | end Null_Exclusion_Static_Checks; |
2951 | ||
9dfe12ae | 2952 | ---------------------------------- |
2953 | -- Conditional_Statements_Begin -- | |
2954 | ---------------------------------- | |
2955 | ||
2956 | procedure Conditional_Statements_Begin is | |
2957 | begin | |
2958 | Saved_Checks_TOS := Saved_Checks_TOS + 1; | |
2959 | ||
feff2f05 | 2960 | -- If stack overflows, kill all checks, that way we know to simply reset |
2961 | -- the number of saved checks to zero on return. This should never occur | |
2962 | -- in practice. | |
9dfe12ae | 2963 | |
2964 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
2965 | Kill_All_Checks; | |
2966 | ||
feff2f05 | 2967 | -- In the normal case, we just make a new stack entry saving the current |
2968 | -- number of saved checks for a later restore. | |
9dfe12ae | 2969 | |
2970 | else | |
2971 | Saved_Checks_Stack (Saved_Checks_TOS) := Num_Saved_Checks; | |
2972 | ||
2973 | if Debug_Flag_CC then | |
2974 | w ("Conditional_Statements_Begin: Num_Saved_Checks = ", | |
2975 | Num_Saved_Checks); | |
2976 | end if; | |
2977 | end if; | |
2978 | end Conditional_Statements_Begin; | |
2979 | ||
2980 | -------------------------------- | |
2981 | -- Conditional_Statements_End -- | |
2982 | -------------------------------- | |
2983 | ||
2984 | procedure Conditional_Statements_End is | |
2985 | begin | |
2986 | pragma Assert (Saved_Checks_TOS > 0); | |
2987 | ||
feff2f05 | 2988 | -- If the saved checks stack overflowed, then we killed all checks, so |
2989 | -- setting the number of saved checks back to zero is correct. This | |
2990 | -- should never occur in practice. | |
9dfe12ae | 2991 | |
2992 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
2993 | Num_Saved_Checks := 0; | |
2994 | ||
feff2f05 | 2995 | -- In the normal case, restore the number of saved checks from the top |
2996 | -- stack entry. | |
9dfe12ae | 2997 | |
2998 | else | |
2999 | Num_Saved_Checks := Saved_Checks_Stack (Saved_Checks_TOS); | |
3000 | if Debug_Flag_CC then | |
3001 | w ("Conditional_Statements_End: Num_Saved_Checks = ", | |
3002 | Num_Saved_Checks); | |
3003 | end if; | |
3004 | end if; | |
3005 | ||
3006 | Saved_Checks_TOS := Saved_Checks_TOS - 1; | |
3007 | end Conditional_Statements_End; | |
3008 | ||
ee6ba406 | 3009 | --------------------- |
3010 | -- Determine_Range -- | |
3011 | --------------------- | |
3012 | ||
6af1bdbc | 3013 | Cache_Size : constant := 2 ** 10; |
ee6ba406 | 3014 | type Cache_Index is range 0 .. Cache_Size - 1; |
3015 | -- Determine size of below cache (power of 2 is more efficient!) | |
3016 | ||
3017 | Determine_Range_Cache_N : array (Cache_Index) of Node_Id; | |
9c486805 | 3018 | Determine_Range_Cache_V : array (Cache_Index) of Boolean; |
ee6ba406 | 3019 | Determine_Range_Cache_Lo : array (Cache_Index) of Uint; |
3020 | Determine_Range_Cache_Hi : array (Cache_Index) of Uint; | |
feff2f05 | 3021 | -- The above arrays are used to implement a small direct cache for |
3022 | -- Determine_Range calls. Because of the way Determine_Range recursively | |
3023 | -- traces subexpressions, and because overflow checking calls the routine | |
3024 | -- on the way up the tree, a quadratic behavior can otherwise be | |
3025 | -- encountered in large expressions. The cache entry for node N is stored | |
3026 | -- in the (N mod Cache_Size) entry, and can be validated by checking the | |
9c486805 | 3027 | -- actual node value stored there. The Range_Cache_V array records the |
3028 | -- setting of Assume_Valid for the cache entry. | |
ee6ba406 | 3029 | |
3030 | procedure Determine_Range | |
9c486805 | 3031 | (N : Node_Id; |
3032 | OK : out Boolean; | |
3033 | Lo : out Uint; | |
3034 | Hi : out Uint; | |
3035 | Assume_Valid : Boolean := False) | |
ee6ba406 | 3036 | is |
e254d721 | 3037 | Typ : Entity_Id := Etype (N); |
3038 | -- Type to use, may get reset to base type for possibly invalid entity | |
8880be85 | 3039 | |
3040 | Lo_Left : Uint; | |
3041 | Hi_Left : Uint; | |
3042 | -- Lo and Hi bounds of left operand | |
ee6ba406 | 3043 | |
ee6ba406 | 3044 | Lo_Right : Uint; |
ee6ba406 | 3045 | Hi_Right : Uint; |
8880be85 | 3046 | -- Lo and Hi bounds of right (or only) operand |
3047 | ||
3048 | Bound : Node_Id; | |
3049 | -- Temp variable used to hold a bound node | |
3050 | ||
3051 | Hbound : Uint; | |
3052 | -- High bound of base type of expression | |
3053 | ||
3054 | Lor : Uint; | |
3055 | Hir : Uint; | |
3056 | -- Refined values for low and high bounds, after tightening | |
3057 | ||
3058 | OK1 : Boolean; | |
3059 | -- Used in lower level calls to indicate if call succeeded | |
3060 | ||
3061 | Cindex : Cache_Index; | |
3062 | -- Used to search cache | |
ee6ba406 | 3063 | |
3064 | function OK_Operands return Boolean; | |
3065 | -- Used for binary operators. Determines the ranges of the left and | |
3066 | -- right operands, and if they are both OK, returns True, and puts | |
341bd953 | 3067 | -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left. |
ee6ba406 | 3068 | |
3069 | ----------------- | |
3070 | -- OK_Operands -- | |
3071 | ----------------- | |
3072 | ||
3073 | function OK_Operands return Boolean is | |
3074 | begin | |
9c486805 | 3075 | Determine_Range |
3076 | (Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid); | |
ee6ba406 | 3077 | |
3078 | if not OK1 then | |
3079 | return False; | |
3080 | end if; | |
3081 | ||
9c486805 | 3082 | Determine_Range |
3083 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
ee6ba406 | 3084 | return OK1; |
3085 | end OK_Operands; | |
3086 | ||
3087 | -- Start of processing for Determine_Range | |
3088 | ||
3089 | begin | |
3090 | -- Prevent junk warnings by initializing range variables | |
3091 | ||
3092 | Lo := No_Uint; | |
3093 | Hi := No_Uint; | |
3094 | Lor := No_Uint; | |
3095 | Hir := No_Uint; | |
3096 | ||
a781c0fc | 3097 | -- If type is not defined, we can't determine its range |
ee6ba406 | 3098 | |
a781c0fc | 3099 | if No (Typ) |
3100 | ||
3101 | -- We don't deal with anything except discrete types | |
3102 | ||
3103 | or else not Is_Discrete_Type (Typ) | |
3104 | ||
3105 | -- Ignore type for which an error has been posted, since range in | |
3106 | -- this case may well be a bogosity deriving from the error. Also | |
3107 | -- ignore if error posted on the reference node. | |
3108 | ||
3109 | or else Error_Posted (N) or else Error_Posted (Typ) | |
ee6ba406 | 3110 | then |
3111 | OK := False; | |
3112 | return; | |
3113 | end if; | |
3114 | ||
3115 | -- For all other cases, we can determine the range | |
3116 | ||
3117 | OK := True; | |
3118 | ||
feff2f05 | 3119 | -- If value is compile time known, then the possible range is the one |
3120 | -- value that we know this expression definitely has! | |
ee6ba406 | 3121 | |
3122 | if Compile_Time_Known_Value (N) then | |
3123 | Lo := Expr_Value (N); | |
3124 | Hi := Lo; | |
3125 | return; | |
3126 | end if; | |
3127 | ||
3128 | -- Return if already in the cache | |
3129 | ||
3130 | Cindex := Cache_Index (N mod Cache_Size); | |
3131 | ||
9c486805 | 3132 | if Determine_Range_Cache_N (Cindex) = N |
3133 | and then | |
3134 | Determine_Range_Cache_V (Cindex) = Assume_Valid | |
3135 | then | |
ee6ba406 | 3136 | Lo := Determine_Range_Cache_Lo (Cindex); |
3137 | Hi := Determine_Range_Cache_Hi (Cindex); | |
3138 | return; | |
3139 | end if; | |
3140 | ||
feff2f05 | 3141 | -- Otherwise, start by finding the bounds of the type of the expression, |
3142 | -- the value cannot be outside this range (if it is, then we have an | |
3143 | -- overflow situation, which is a separate check, we are talking here | |
3144 | -- only about the expression value). | |
ee6ba406 | 3145 | |
341bd953 | 3146 | -- First a check, never try to find the bounds of a generic type, since |
3147 | -- these bounds are always junk values, and it is only valid to look at | |
3148 | -- the bounds in an instance. | |
3149 | ||
3150 | if Is_Generic_Type (Typ) then | |
3151 | OK := False; | |
3152 | return; | |
3153 | end if; | |
3154 | ||
9c486805 | 3155 | -- First step, change to use base type unless we know the value is valid |
e254d721 | 3156 | |
9c486805 | 3157 | if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N))) |
3158 | or else Assume_No_Invalid_Values | |
3159 | or else Assume_Valid | |
e254d721 | 3160 | then |
9c486805 | 3161 | null; |
3162 | else | |
3163 | Typ := Underlying_Type (Base_Type (Typ)); | |
e254d721 | 3164 | end if; |
3165 | ||
feff2f05 | 3166 | -- We use the actual bound unless it is dynamic, in which case use the |
3167 | -- corresponding base type bound if possible. If we can't get a bound | |
3168 | -- then we figure we can't determine the range (a peculiar case, that | |
3169 | -- perhaps cannot happen, but there is no point in bombing in this | |
3170 | -- optimization circuit. | |
8880be85 | 3171 | |
3172 | -- First the low bound | |
ee6ba406 | 3173 | |
3174 | Bound := Type_Low_Bound (Typ); | |
3175 | ||
3176 | if Compile_Time_Known_Value (Bound) then | |
3177 | Lo := Expr_Value (Bound); | |
3178 | ||
3179 | elsif Compile_Time_Known_Value (Type_Low_Bound (Base_Type (Typ))) then | |
3180 | Lo := Expr_Value (Type_Low_Bound (Base_Type (Typ))); | |
3181 | ||
3182 | else | |
3183 | OK := False; | |
3184 | return; | |
3185 | end if; | |
3186 | ||
8880be85 | 3187 | -- Now the high bound |
3188 | ||
ee6ba406 | 3189 | Bound := Type_High_Bound (Typ); |
3190 | ||
8880be85 | 3191 | -- We need the high bound of the base type later on, and this should |
3192 | -- always be compile time known. Again, it is not clear that this | |
3193 | -- can ever be false, but no point in bombing. | |
ee6ba406 | 3194 | |
8880be85 | 3195 | if Compile_Time_Known_Value (Type_High_Bound (Base_Type (Typ))) then |
ee6ba406 | 3196 | Hbound := Expr_Value (Type_High_Bound (Base_Type (Typ))); |
3197 | Hi := Hbound; | |
3198 | ||
3199 | else | |
3200 | OK := False; | |
3201 | return; | |
3202 | end if; | |
3203 | ||
feff2f05 | 3204 | -- If we have a static subtype, then that may have a tighter bound so |
3205 | -- use the upper bound of the subtype instead in this case. | |
8880be85 | 3206 | |
3207 | if Compile_Time_Known_Value (Bound) then | |
3208 | Hi := Expr_Value (Bound); | |
3209 | end if; | |
3210 | ||
feff2f05 | 3211 | -- We may be able to refine this value in certain situations. If any |
3212 | -- refinement is possible, then Lor and Hir are set to possibly tighter | |
3213 | -- bounds, and OK1 is set to True. | |
ee6ba406 | 3214 | |
3215 | case Nkind (N) is | |
3216 | ||
3217 | -- For unary plus, result is limited by range of operand | |
3218 | ||
3219 | when N_Op_Plus => | |
9c486805 | 3220 | Determine_Range |
3221 | (Right_Opnd (N), OK1, Lor, Hir, Assume_Valid); | |
ee6ba406 | 3222 | |
3223 | -- For unary minus, determine range of operand, and negate it | |
3224 | ||
3225 | when N_Op_Minus => | |
9c486805 | 3226 | Determine_Range |
3227 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
ee6ba406 | 3228 | |
3229 | if OK1 then | |
3230 | Lor := -Hi_Right; | |
3231 | Hir := -Lo_Right; | |
3232 | end if; | |
3233 | ||
3234 | -- For binary addition, get range of each operand and do the | |
3235 | -- addition to get the result range. | |
3236 | ||
3237 | when N_Op_Add => | |
3238 | if OK_Operands then | |
3239 | Lor := Lo_Left + Lo_Right; | |
3240 | Hir := Hi_Left + Hi_Right; | |
3241 | end if; | |
3242 | ||
feff2f05 | 3243 | -- Division is tricky. The only case we consider is where the right |
3244 | -- operand is a positive constant, and in this case we simply divide | |
3245 | -- the bounds of the left operand | |
ee6ba406 | 3246 | |
3247 | when N_Op_Divide => | |
3248 | if OK_Operands then | |
3249 | if Lo_Right = Hi_Right | |
3250 | and then Lo_Right > 0 | |
3251 | then | |
3252 | Lor := Lo_Left / Lo_Right; | |
3253 | Hir := Hi_Left / Lo_Right; | |
3254 | ||
3255 | else | |
3256 | OK1 := False; | |
3257 | end if; | |
3258 | end if; | |
3259 | ||
feff2f05 | 3260 | -- For binary subtraction, get range of each operand and do the worst |
3261 | -- case subtraction to get the result range. | |
ee6ba406 | 3262 | |
3263 | when N_Op_Subtract => | |
3264 | if OK_Operands then | |
3265 | Lor := Lo_Left - Hi_Right; | |
3266 | Hir := Hi_Left - Lo_Right; | |
3267 | end if; | |
3268 | ||
feff2f05 | 3269 | -- For MOD, if right operand is a positive constant, then result must |
3270 | -- be in the allowable range of mod results. | |
ee6ba406 | 3271 | |
3272 | when N_Op_Mod => | |
3273 | if OK_Operands then | |
9dfe12ae | 3274 | if Lo_Right = Hi_Right |
3275 | and then Lo_Right /= 0 | |
3276 | then | |
ee6ba406 | 3277 | if Lo_Right > 0 then |
3278 | Lor := Uint_0; | |
3279 | Hir := Lo_Right - 1; | |
3280 | ||
9dfe12ae | 3281 | else -- Lo_Right < 0 |
ee6ba406 | 3282 | Lor := Lo_Right + 1; |
3283 | Hir := Uint_0; | |
3284 | end if; | |
3285 | ||
3286 | else | |
3287 | OK1 := False; | |
3288 | end if; | |
3289 | end if; | |
3290 | ||
feff2f05 | 3291 | -- For REM, if right operand is a positive constant, then result must |
3292 | -- be in the allowable range of mod results. | |
ee6ba406 | 3293 | |
3294 | when N_Op_Rem => | |
3295 | if OK_Operands then | |
9dfe12ae | 3296 | if Lo_Right = Hi_Right |
3297 | and then Lo_Right /= 0 | |
3298 | then | |
ee6ba406 | 3299 | declare |
3300 | Dval : constant Uint := (abs Lo_Right) - 1; | |
3301 | ||
3302 | begin | |
3303 | -- The sign of the result depends on the sign of the | |
3304 | -- dividend (but not on the sign of the divisor, hence | |
3305 | -- the abs operation above). | |
3306 | ||
3307 | if Lo_Left < 0 then | |
3308 | Lor := -Dval; | |
3309 | else | |
3310 | Lor := Uint_0; | |
3311 | end if; | |
3312 | ||
3313 | if Hi_Left < 0 then | |
3314 | Hir := Uint_0; | |
3315 | else | |
3316 | Hir := Dval; | |
3317 | end if; | |
3318 | end; | |
3319 | ||
3320 | else | |
3321 | OK1 := False; | |
3322 | end if; | |
3323 | end if; | |
3324 | ||
3325 | -- Attribute reference cases | |
3326 | ||
3327 | when N_Attribute_Reference => | |
3328 | case Attribute_Name (N) is | |
3329 | ||
3330 | -- For Pos/Val attributes, we can refine the range using the | |
ddbf7f2e | 3331 | -- possible range of values of the attribute expression. |
ee6ba406 | 3332 | |
3333 | when Name_Pos | Name_Val => | |
9c486805 | 3334 | Determine_Range |
3335 | (First (Expressions (N)), OK1, Lor, Hir, Assume_Valid); | |
ee6ba406 | 3336 | |
3337 | -- For Length attribute, use the bounds of the corresponding | |
3338 | -- index type to refine the range. | |
3339 | ||
3340 | when Name_Length => | |
3341 | declare | |
3342 | Atyp : Entity_Id := Etype (Prefix (N)); | |
3343 | Inum : Nat; | |
3344 | Indx : Node_Id; | |
3345 | ||
3346 | LL, LU : Uint; | |
3347 | UL, UU : Uint; | |
3348 | ||
3349 | begin | |
3350 | if Is_Access_Type (Atyp) then | |
3351 | Atyp := Designated_Type (Atyp); | |
3352 | end if; | |
3353 | ||
3354 | -- For string literal, we know exact value | |
3355 | ||
3356 | if Ekind (Atyp) = E_String_Literal_Subtype then | |
3357 | OK := True; | |
3358 | Lo := String_Literal_Length (Atyp); | |
3359 | Hi := String_Literal_Length (Atyp); | |
3360 | return; | |
3361 | end if; | |
3362 | ||
3363 | -- Otherwise check for expression given | |
3364 | ||
3365 | if No (Expressions (N)) then | |
3366 | Inum := 1; | |
3367 | else | |
3368 | Inum := | |
3369 | UI_To_Int (Expr_Value (First (Expressions (N)))); | |
3370 | end if; | |
3371 | ||
3372 | Indx := First_Index (Atyp); | |
3373 | for J in 2 .. Inum loop | |
3374 | Indx := Next_Index (Indx); | |
3375 | end loop; | |
3376 | ||
9116df93 | 3377 | -- If the index type is a formal type or derived from |
c8da6114 | 3378 | -- one, the bounds are not static. |
3379 | ||
3380 | if Is_Generic_Type (Root_Type (Etype (Indx))) then | |
3381 | OK := False; | |
3382 | return; | |
3383 | end if; | |
3384 | ||
ee6ba406 | 3385 | Determine_Range |
9c486805 | 3386 | (Type_Low_Bound (Etype (Indx)), OK1, LL, LU, |
3387 | Assume_Valid); | |
ee6ba406 | 3388 | |
3389 | if OK1 then | |
3390 | Determine_Range | |
9c486805 | 3391 | (Type_High_Bound (Etype (Indx)), OK1, UL, UU, |
3392 | Assume_Valid); | |
ee6ba406 | 3393 | |
3394 | if OK1 then | |
3395 | ||
3396 | -- The maximum value for Length is the biggest | |
3397 | -- possible gap between the values of the bounds. | |
3398 | -- But of course, this value cannot be negative. | |
3399 | ||
9c486805 | 3400 | Hir := UI_Max (Uint_0, UU - LL + 1); |
ee6ba406 | 3401 | |
3402 | -- For constrained arrays, the minimum value for | |
3403 | -- Length is taken from the actual value of the | |
9116df93 | 3404 | -- bounds, since the index will be exactly of this |
3405 | -- subtype. | |
ee6ba406 | 3406 | |
3407 | if Is_Constrained (Atyp) then | |
9c486805 | 3408 | Lor := UI_Max (Uint_0, UL - LU + 1); |
ee6ba406 | 3409 | |
3410 | -- For an unconstrained array, the minimum value | |
3411 | -- for length is always zero. | |
3412 | ||
3413 | else | |
3414 | Lor := Uint_0; | |
3415 | end if; | |
3416 | end if; | |
3417 | end if; | |
3418 | end; | |
3419 | ||
3420 | -- No special handling for other attributes | |
9116df93 | 3421 | -- Probably more opportunities exist here??? |
ee6ba406 | 3422 | |
3423 | when others => | |
3424 | OK1 := False; | |
3425 | ||
3426 | end case; | |
3427 | ||
feff2f05 | 3428 | -- For type conversion from one discrete type to another, we can |
3429 | -- refine the range using the converted value. | |
ee6ba406 | 3430 | |
3431 | when N_Type_Conversion => | |
9c486805 | 3432 | Determine_Range (Expression (N), OK1, Lor, Hir, Assume_Valid); |
ee6ba406 | 3433 | |
3434 | -- Nothing special to do for all other expression kinds | |
3435 | ||
3436 | when others => | |
3437 | OK1 := False; | |
3438 | Lor := No_Uint; | |
3439 | Hir := No_Uint; | |
3440 | end case; | |
3441 | ||
9116df93 | 3442 | -- At this stage, if OK1 is true, then we know that the actual result of |
3443 | -- the computed expression is in the range Lor .. Hir. We can use this | |
3444 | -- to restrict the possible range of results. | |
ee6ba406 | 3445 | |
3446 | if OK1 then | |
3447 | ||
9116df93 | 3448 | -- If the refined value of the low bound is greater than the type |
3449 | -- high bound, then reset it to the more restrictive value. However, | |
3450 | -- we do NOT do this for the case of a modular type where the | |
3451 | -- possible upper bound on the value is above the base type high | |
3452 | -- bound, because that means the result could wrap. | |
ee6ba406 | 3453 | |
3454 | if Lor > Lo | |
9116df93 | 3455 | and then not (Is_Modular_Integer_Type (Typ) and then Hir > Hbound) |
ee6ba406 | 3456 | then |
3457 | Lo := Lor; | |
3458 | end if; | |
3459 | ||
9116df93 | 3460 | -- Similarly, if the refined value of the high bound is less than the |
3461 | -- value so far, then reset it to the more restrictive value. Again, | |
3462 | -- we do not do this if the refined low bound is negative for a | |
3463 | -- modular type, since this would wrap. | |
ee6ba406 | 3464 | |
3465 | if Hir < Hi | |
9116df93 | 3466 | and then not (Is_Modular_Integer_Type (Typ) and then Lor < Uint_0) |
ee6ba406 | 3467 | then |
3468 | Hi := Hir; | |
3469 | end if; | |
3470 | end if; | |
3471 | ||
3472 | -- Set cache entry for future call and we are all done | |
3473 | ||
3474 | Determine_Range_Cache_N (Cindex) := N; | |
9c486805 | 3475 | Determine_Range_Cache_V (Cindex) := Assume_Valid; |
ee6ba406 | 3476 | Determine_Range_Cache_Lo (Cindex) := Lo; |
3477 | Determine_Range_Cache_Hi (Cindex) := Hi; | |
3478 | return; | |
3479 | ||
9116df93 | 3480 | -- If any exception occurs, it means that we have some bug in the compiler, |
3481 | -- possibly triggered by a previous error, or by some unforeseen peculiar | |
ee6ba406 | 3482 | -- occurrence. However, this is only an optimization attempt, so there is |
3483 | -- really no point in crashing the compiler. Instead we just decide, too | |
3484 | -- bad, we can't figure out a range in this case after all. | |
3485 | ||
3486 | exception | |
3487 | when others => | |
3488 | ||
3489 | -- Debug flag K disables this behavior (useful for debugging) | |
3490 | ||
3491 | if Debug_Flag_K then | |
3492 | raise; | |
3493 | else | |
3494 | OK := False; | |
3495 | Lo := No_Uint; | |
3496 | Hi := No_Uint; | |
3497 | return; | |
3498 | end if; | |
ee6ba406 | 3499 | end Determine_Range; |
3500 | ||
3501 | ------------------------------------ | |
3502 | -- Discriminant_Checks_Suppressed -- | |
3503 | ------------------------------------ | |
3504 | ||
3505 | function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is | |
3506 | begin | |
9dfe12ae | 3507 | if Present (E) then |
3508 | if Is_Unchecked_Union (E) then | |
3509 | return True; | |
3510 | elsif Checks_May_Be_Suppressed (E) then | |
3511 | return Is_Check_Suppressed (E, Discriminant_Check); | |
3512 | end if; | |
3513 | end if; | |
3514 | ||
3515 | return Scope_Suppress (Discriminant_Check); | |
ee6ba406 | 3516 | end Discriminant_Checks_Suppressed; |
3517 | ||
3518 | -------------------------------- | |
3519 | -- Division_Checks_Suppressed -- | |
3520 | -------------------------------- | |
3521 | ||
3522 | function Division_Checks_Suppressed (E : Entity_Id) return Boolean is | |
3523 | begin | |
9dfe12ae | 3524 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
3525 | return Is_Check_Suppressed (E, Division_Check); | |
3526 | else | |
3527 | return Scope_Suppress (Division_Check); | |
3528 | end if; | |
ee6ba406 | 3529 | end Division_Checks_Suppressed; |
3530 | ||
3531 | ----------------------------------- | |
3532 | -- Elaboration_Checks_Suppressed -- | |
3533 | ----------------------------------- | |
3534 | ||
3535 | function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is | |
3536 | begin | |
38f5559f | 3537 | -- The complication in this routine is that if we are in the dynamic |
3538 | -- model of elaboration, we also check All_Checks, since All_Checks | |
3539 | -- does not set Elaboration_Check explicitly. | |
3540 | ||
9dfe12ae | 3541 | if Present (E) then |
3542 | if Kill_Elaboration_Checks (E) then | |
3543 | return True; | |
38f5559f | 3544 | |
9dfe12ae | 3545 | elsif Checks_May_Be_Suppressed (E) then |
38f5559f | 3546 | if Is_Check_Suppressed (E, Elaboration_Check) then |
3547 | return True; | |
3548 | elsif Dynamic_Elaboration_Checks then | |
3549 | return Is_Check_Suppressed (E, All_Checks); | |
3550 | else | |
3551 | return False; | |
3552 | end if; | |
9dfe12ae | 3553 | end if; |
3554 | end if; | |
3555 | ||
38f5559f | 3556 | if Scope_Suppress (Elaboration_Check) then |
3557 | return True; | |
3558 | elsif Dynamic_Elaboration_Checks then | |
3559 | return Scope_Suppress (All_Checks); | |
3560 | else | |
3561 | return False; | |
3562 | end if; | |
ee6ba406 | 3563 | end Elaboration_Checks_Suppressed; |
3564 | ||
9dfe12ae | 3565 | --------------------------- |
3566 | -- Enable_Overflow_Check -- | |
3567 | --------------------------- | |
3568 | ||
3569 | procedure Enable_Overflow_Check (N : Node_Id) is | |
3570 | Typ : constant Entity_Id := Base_Type (Etype (N)); | |
3571 | Chk : Nat; | |
3572 | OK : Boolean; | |
3573 | Ent : Entity_Id; | |
3574 | Ofs : Uint; | |
3575 | Lo : Uint; | |
3576 | Hi : Uint; | |
ee6ba406 | 3577 | |
ee6ba406 | 3578 | begin |
9dfe12ae | 3579 | if Debug_Flag_CC then |
3580 | w ("Enable_Overflow_Check for node ", Int (N)); | |
3581 | Write_Str (" Source location = "); | |
3582 | wl (Sloc (N)); | |
00c403ee | 3583 | pg (Union_Id (N)); |
ee6ba406 | 3584 | end if; |
ee6ba406 | 3585 | |
75209ec5 | 3586 | -- No check if overflow checks suppressed for type of node |
3587 | ||
3588 | if Present (Etype (N)) | |
3589 | and then Overflow_Checks_Suppressed (Etype (N)) | |
3590 | then | |
3591 | return; | |
3592 | ||
49260fa5 | 3593 | -- Nothing to do for unsigned integer types, which do not overflow |
3594 | ||
3595 | elsif Is_Modular_Integer_Type (Typ) then | |
3596 | return; | |
3597 | ||
feff2f05 | 3598 | -- Nothing to do if the range of the result is known OK. We skip this |
3599 | -- for conversions, since the caller already did the check, and in any | |
3600 | -- case the condition for deleting the check for a type conversion is | |
cc60bd16 | 3601 | -- different. |
ee6ba406 | 3602 | |
75209ec5 | 3603 | elsif Nkind (N) /= N_Type_Conversion then |
9c486805 | 3604 | Determine_Range (N, OK, Lo, Hi, Assume_Valid => True); |
ee6ba406 | 3605 | |
cc60bd16 | 3606 | -- Note in the test below that we assume that the range is not OK |
3607 | -- if a bound of the range is equal to that of the type. That's not | |
3608 | -- quite accurate but we do this for the following reasons: | |
ee6ba406 | 3609 | |
9dfe12ae | 3610 | -- a) The way that Determine_Range works, it will typically report |
3611 | -- the bounds of the value as being equal to the bounds of the | |
3612 | -- type, because it either can't tell anything more precise, or | |
3613 | -- does not think it is worth the effort to be more precise. | |
ee6ba406 | 3614 | |
9dfe12ae | 3615 | -- b) It is very unusual to have a situation in which this would |
3616 | -- generate an unnecessary overflow check (an example would be | |
3617 | -- a subtype with a range 0 .. Integer'Last - 1 to which the | |
cc60bd16 | 3618 | -- literal value one is added). |
ee6ba406 | 3619 | |
9dfe12ae | 3620 | -- c) The alternative is a lot of special casing in this routine |
3621 | -- which would partially duplicate Determine_Range processing. | |
ee6ba406 | 3622 | |
9dfe12ae | 3623 | if OK |
3624 | and then Lo > Expr_Value (Type_Low_Bound (Typ)) | |
3625 | and then Hi < Expr_Value (Type_High_Bound (Typ)) | |
3626 | then | |
3627 | if Debug_Flag_CC then | |
3628 | w ("No overflow check required"); | |
3629 | end if; | |
3630 | ||
3631 | return; | |
3632 | end if; | |
3633 | end if; | |
3634 | ||
feff2f05 | 3635 | -- If not in optimizing mode, set flag and we are done. We are also done |
3636 | -- (and just set the flag) if the type is not a discrete type, since it | |
3637 | -- is not worth the effort to eliminate checks for other than discrete | |
3638 | -- types. In addition, we take this same path if we have stored the | |
3639 | -- maximum number of checks possible already (a very unlikely situation, | |
3640 | -- but we do not want to blow up!) | |
9dfe12ae | 3641 | |
3642 | if Optimization_Level = 0 | |
3643 | or else not Is_Discrete_Type (Etype (N)) | |
3644 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 3645 | then |
00c403ee | 3646 | Activate_Overflow_Check (N); |
9dfe12ae | 3647 | |
3648 | if Debug_Flag_CC then | |
3649 | w ("Optimization off"); | |
3650 | end if; | |
3651 | ||
ee6ba406 | 3652 | return; |
9dfe12ae | 3653 | end if; |
ee6ba406 | 3654 | |
9dfe12ae | 3655 | -- Otherwise evaluate and check the expression |
3656 | ||
3657 | Find_Check | |
3658 | (Expr => N, | |
3659 | Check_Type => 'O', | |
3660 | Target_Type => Empty, | |
3661 | Entry_OK => OK, | |
3662 | Check_Num => Chk, | |
3663 | Ent => Ent, | |
3664 | Ofs => Ofs); | |
3665 | ||
3666 | if Debug_Flag_CC then | |
3667 | w ("Called Find_Check"); | |
3668 | w (" OK = ", OK); | |
3669 | ||
3670 | if OK then | |
3671 | w (" Check_Num = ", Chk); | |
3672 | w (" Ent = ", Int (Ent)); | |
3673 | Write_Str (" Ofs = "); | |
3674 | pid (Ofs); | |
3675 | end if; | |
3676 | end if; | |
ee6ba406 | 3677 | |
9dfe12ae | 3678 | -- If check is not of form to optimize, then set flag and we are done |
3679 | ||
3680 | if not OK then | |
00c403ee | 3681 | Activate_Overflow_Check (N); |
ee6ba406 | 3682 | return; |
9dfe12ae | 3683 | end if; |
ee6ba406 | 3684 | |
9dfe12ae | 3685 | -- If check is already performed, then return without setting flag |
3686 | ||
3687 | if Chk /= 0 then | |
3688 | if Debug_Flag_CC then | |
3689 | w ("Check suppressed!"); | |
3690 | end if; | |
ee6ba406 | 3691 | |
ee6ba406 | 3692 | return; |
9dfe12ae | 3693 | end if; |
ee6ba406 | 3694 | |
9dfe12ae | 3695 | -- Here we will make a new entry for the new check |
3696 | ||
00c403ee | 3697 | Activate_Overflow_Check (N); |
9dfe12ae | 3698 | Num_Saved_Checks := Num_Saved_Checks + 1; |
3699 | Saved_Checks (Num_Saved_Checks) := | |
3700 | (Killed => False, | |
3701 | Entity => Ent, | |
3702 | Offset => Ofs, | |
3703 | Check_Type => 'O', | |
3704 | Target_Type => Empty); | |
3705 | ||
3706 | if Debug_Flag_CC then | |
3707 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
3708 | w (" Entity = ", Int (Ent)); | |
3709 | Write_Str (" Offset = "); | |
3710 | pid (Ofs); | |
3711 | w (" Check_Type = O"); | |
3712 | w (" Target_Type = Empty"); | |
3713 | end if; | |
ee6ba406 | 3714 | |
feff2f05 | 3715 | -- If we get an exception, then something went wrong, probably because of |
3716 | -- an error in the structure of the tree due to an incorrect program. Or it | |
3717 | -- may be a bug in the optimization circuit. In either case the safest | |
3718 | -- thing is simply to set the check flag unconditionally. | |
9dfe12ae | 3719 | |
3720 | exception | |
3721 | when others => | |
00c403ee | 3722 | Activate_Overflow_Check (N); |
9dfe12ae | 3723 | |
3724 | if Debug_Flag_CC then | |
3725 | w (" exception occurred, overflow flag set"); | |
3726 | end if; | |
3727 | ||
3728 | return; | |
3729 | end Enable_Overflow_Check; | |
3730 | ||
3731 | ------------------------ | |
3732 | -- Enable_Range_Check -- | |
3733 | ------------------------ | |
3734 | ||
3735 | procedure Enable_Range_Check (N : Node_Id) is | |
3736 | Chk : Nat; | |
3737 | OK : Boolean; | |
3738 | Ent : Entity_Id; | |
3739 | Ofs : Uint; | |
3740 | Ttyp : Entity_Id; | |
3741 | P : Node_Id; | |
3742 | ||
3743 | begin | |
feff2f05 | 3744 | -- Return if unchecked type conversion with range check killed. In this |
3745 | -- case we never set the flag (that's what Kill_Range_Check is about!) | |
9dfe12ae | 3746 | |
3747 | if Nkind (N) = N_Unchecked_Type_Conversion | |
3748 | and then Kill_Range_Check (N) | |
ee6ba406 | 3749 | then |
3750 | return; | |
9dfe12ae | 3751 | end if; |
ee6ba406 | 3752 | |
55e8372b | 3753 | -- Do not set range check flag if parent is assignment statement or |
3754 | -- object declaration with Suppress_Assignment_Checks flag set | |
3755 | ||
3756 | if Nkind_In (Parent (N), N_Assignment_Statement, N_Object_Declaration) | |
3757 | and then Suppress_Assignment_Checks (Parent (N)) | |
3758 | then | |
3759 | return; | |
3760 | end if; | |
3761 | ||
0577b0b1 | 3762 | -- Check for various cases where we should suppress the range check |
3763 | ||
3764 | -- No check if range checks suppressed for type of node | |
3765 | ||
3766 | if Present (Etype (N)) | |
3767 | and then Range_Checks_Suppressed (Etype (N)) | |
3768 | then | |
3769 | return; | |
3770 | ||
3771 | -- No check if node is an entity name, and range checks are suppressed | |
3772 | -- for this entity, or for the type of this entity. | |
3773 | ||
3774 | elsif Is_Entity_Name (N) | |
3775 | and then (Range_Checks_Suppressed (Entity (N)) | |
3776 | or else Range_Checks_Suppressed (Etype (Entity (N)))) | |
3777 | then | |
3778 | return; | |
3779 | ||
3780 | -- No checks if index of array, and index checks are suppressed for | |
3781 | -- the array object or the type of the array. | |
3782 | ||
3783 | elsif Nkind (Parent (N)) = N_Indexed_Component then | |
3784 | declare | |
3785 | Pref : constant Node_Id := Prefix (Parent (N)); | |
3786 | begin | |
3787 | if Is_Entity_Name (Pref) | |
3788 | and then Index_Checks_Suppressed (Entity (Pref)) | |
3789 | then | |
3790 | return; | |
3791 | elsif Index_Checks_Suppressed (Etype (Pref)) then | |
3792 | return; | |
3793 | end if; | |
3794 | end; | |
3795 | end if; | |
3796 | ||
9dfe12ae | 3797 | -- Debug trace output |
ee6ba406 | 3798 | |
9dfe12ae | 3799 | if Debug_Flag_CC then |
3800 | w ("Enable_Range_Check for node ", Int (N)); | |
3801 | Write_Str (" Source location = "); | |
3802 | wl (Sloc (N)); | |
00c403ee | 3803 | pg (Union_Id (N)); |
9dfe12ae | 3804 | end if; |
3805 | ||
feff2f05 | 3806 | -- If not in optimizing mode, set flag and we are done. We are also done |
3807 | -- (and just set the flag) if the type is not a discrete type, since it | |
3808 | -- is not worth the effort to eliminate checks for other than discrete | |
3809 | -- types. In addition, we take this same path if we have stored the | |
3810 | -- maximum number of checks possible already (a very unlikely situation, | |
3811 | -- but we do not want to blow up!) | |
9dfe12ae | 3812 | |
3813 | if Optimization_Level = 0 | |
3814 | or else No (Etype (N)) | |
3815 | or else not Is_Discrete_Type (Etype (N)) | |
3816 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 3817 | then |
00c403ee | 3818 | Activate_Range_Check (N); |
9dfe12ae | 3819 | |
3820 | if Debug_Flag_CC then | |
3821 | w ("Optimization off"); | |
3822 | end if; | |
3823 | ||
ee6ba406 | 3824 | return; |
9dfe12ae | 3825 | end if; |
ee6ba406 | 3826 | |
9dfe12ae | 3827 | -- Otherwise find out the target type |
ee6ba406 | 3828 | |
9dfe12ae | 3829 | P := Parent (N); |
ee6ba406 | 3830 | |
9dfe12ae | 3831 | -- For assignment, use left side subtype |
3832 | ||
3833 | if Nkind (P) = N_Assignment_Statement | |
3834 | and then Expression (P) = N | |
3835 | then | |
3836 | Ttyp := Etype (Name (P)); | |
3837 | ||
3838 | -- For indexed component, use subscript subtype | |
3839 | ||
3840 | elsif Nkind (P) = N_Indexed_Component then | |
3841 | declare | |
3842 | Atyp : Entity_Id; | |
3843 | Indx : Node_Id; | |
3844 | Subs : Node_Id; | |
3845 | ||
3846 | begin | |
3847 | Atyp := Etype (Prefix (P)); | |
3848 | ||
3849 | if Is_Access_Type (Atyp) then | |
3850 | Atyp := Designated_Type (Atyp); | |
f07ea091 | 3851 | |
3852 | -- If the prefix is an access to an unconstrained array, | |
feff2f05 | 3853 | -- perform check unconditionally: it depends on the bounds of |
3854 | -- an object and we cannot currently recognize whether the test | |
3855 | -- may be redundant. | |
f07ea091 | 3856 | |
3857 | if not Is_Constrained (Atyp) then | |
00c403ee | 3858 | Activate_Range_Check (N); |
f07ea091 | 3859 | return; |
3860 | end if; | |
7189d17f | 3861 | |
feff2f05 | 3862 | -- Ditto if the prefix is an explicit dereference whose designated |
3863 | -- type is unconstrained. | |
7189d17f | 3864 | |
3865 | elsif Nkind (Prefix (P)) = N_Explicit_Dereference | |
3866 | and then not Is_Constrained (Atyp) | |
3867 | then | |
00c403ee | 3868 | Activate_Range_Check (N); |
7189d17f | 3869 | return; |
9dfe12ae | 3870 | end if; |
3871 | ||
3872 | Indx := First_Index (Atyp); | |
3873 | Subs := First (Expressions (P)); | |
3874 | loop | |
3875 | if Subs = N then | |
3876 | Ttyp := Etype (Indx); | |
3877 | exit; | |
3878 | end if; | |
3879 | ||
3880 | Next_Index (Indx); | |
3881 | Next (Subs); | |
3882 | end loop; | |
3883 | end; | |
3884 | ||
3885 | -- For now, ignore all other cases, they are not so interesting | |
3886 | ||
3887 | else | |
3888 | if Debug_Flag_CC then | |
3889 | w (" target type not found, flag set"); | |
3890 | end if; | |
3891 | ||
00c403ee | 3892 | Activate_Range_Check (N); |
9dfe12ae | 3893 | return; |
3894 | end if; | |
3895 | ||
3896 | -- Evaluate and check the expression | |
3897 | ||
3898 | Find_Check | |
3899 | (Expr => N, | |
3900 | Check_Type => 'R', | |
3901 | Target_Type => Ttyp, | |
3902 | Entry_OK => OK, | |
3903 | Check_Num => Chk, | |
3904 | Ent => Ent, | |
3905 | Ofs => Ofs); | |
3906 | ||
3907 | if Debug_Flag_CC then | |
3908 | w ("Called Find_Check"); | |
3909 | w ("Target_Typ = ", Int (Ttyp)); | |
3910 | w (" OK = ", OK); | |
3911 | ||
3912 | if OK then | |
3913 | w (" Check_Num = ", Chk); | |
3914 | w (" Ent = ", Int (Ent)); | |
3915 | Write_Str (" Ofs = "); | |
3916 | pid (Ofs); | |
3917 | end if; | |
3918 | end if; | |
3919 | ||
3920 | -- If check is not of form to optimize, then set flag and we are done | |
3921 | ||
3922 | if not OK then | |
3923 | if Debug_Flag_CC then | |
3924 | w (" expression not of optimizable type, flag set"); | |
3925 | end if; | |
3926 | ||
00c403ee | 3927 | Activate_Range_Check (N); |
9dfe12ae | 3928 | return; |
3929 | end if; | |
3930 | ||
3931 | -- If check is already performed, then return without setting flag | |
3932 | ||
3933 | if Chk /= 0 then | |
3934 | if Debug_Flag_CC then | |
3935 | w ("Check suppressed!"); | |
3936 | end if; | |
3937 | ||
3938 | return; | |
3939 | end if; | |
3940 | ||
3941 | -- Here we will make a new entry for the new check | |
3942 | ||
00c403ee | 3943 | Activate_Range_Check (N); |
9dfe12ae | 3944 | Num_Saved_Checks := Num_Saved_Checks + 1; |
3945 | Saved_Checks (Num_Saved_Checks) := | |
3946 | (Killed => False, | |
3947 | Entity => Ent, | |
3948 | Offset => Ofs, | |
3949 | Check_Type => 'R', | |
3950 | Target_Type => Ttyp); | |
3951 | ||
3952 | if Debug_Flag_CC then | |
3953 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
3954 | w (" Entity = ", Int (Ent)); | |
3955 | Write_Str (" Offset = "); | |
3956 | pid (Ofs); | |
3957 | w (" Check_Type = R"); | |
3958 | w (" Target_Type = ", Int (Ttyp)); | |
00c403ee | 3959 | pg (Union_Id (Ttyp)); |
9dfe12ae | 3960 | end if; |
3961 | ||
feff2f05 | 3962 | -- If we get an exception, then something went wrong, probably because of |
3963 | -- an error in the structure of the tree due to an incorrect program. Or | |
3964 | -- it may be a bug in the optimization circuit. In either case the safest | |
3965 | -- thing is simply to set the check flag unconditionally. | |
9dfe12ae | 3966 | |
3967 | exception | |
3968 | when others => | |
00c403ee | 3969 | Activate_Range_Check (N); |
9dfe12ae | 3970 | |
3971 | if Debug_Flag_CC then | |
3972 | w (" exception occurred, range flag set"); | |
3973 | end if; | |
3974 | ||
3975 | return; | |
3976 | end Enable_Range_Check; | |
3977 | ||
3978 | ------------------ | |
3979 | -- Ensure_Valid -- | |
3980 | ------------------ | |
3981 | ||
3982 | procedure Ensure_Valid (Expr : Node_Id; Holes_OK : Boolean := False) is | |
3983 | Typ : constant Entity_Id := Etype (Expr); | |
3984 | ||
3985 | begin | |
3986 | -- Ignore call if we are not doing any validity checking | |
3987 | ||
3988 | if not Validity_Checks_On then | |
3989 | return; | |
3990 | ||
0577b0b1 | 3991 | -- Ignore call if range or validity checks suppressed on entity or type |
9dfe12ae | 3992 | |
0577b0b1 | 3993 | elsif Range_Or_Validity_Checks_Suppressed (Expr) then |
9dfe12ae | 3994 | return; |
3995 | ||
feff2f05 | 3996 | -- No check required if expression is from the expander, we assume the |
3997 | -- expander will generate whatever checks are needed. Note that this is | |
3998 | -- not just an optimization, it avoids infinite recursions! | |
9dfe12ae | 3999 | |
4000 | -- Unchecked conversions must be checked, unless they are initialized | |
4001 | -- scalar values, as in a component assignment in an init proc. | |
4002 | ||
4003 | -- In addition, we force a check if Force_Validity_Checks is set | |
4004 | ||
4005 | elsif not Comes_From_Source (Expr) | |
4006 | and then not Force_Validity_Checks | |
4007 | and then (Nkind (Expr) /= N_Unchecked_Type_Conversion | |
4008 | or else Kill_Range_Check (Expr)) | |
4009 | then | |
4010 | return; | |
4011 | ||
4012 | -- No check required if expression is known to have valid value | |
4013 | ||
4014 | elsif Expr_Known_Valid (Expr) then | |
4015 | return; | |
4016 | ||
feff2f05 | 4017 | -- Ignore case of enumeration with holes where the flag is set not to |
4018 | -- worry about holes, since no special validity check is needed | |
9dfe12ae | 4019 | |
4020 | elsif Is_Enumeration_Type (Typ) | |
4021 | and then Has_Non_Standard_Rep (Typ) | |
4022 | and then Holes_OK | |
4023 | then | |
4024 | return; | |
4025 | ||
f2a06be9 | 4026 | -- No check required on the left-hand side of an assignment |
9dfe12ae | 4027 | |
4028 | elsif Nkind (Parent (Expr)) = N_Assignment_Statement | |
4029 | and then Expr = Name (Parent (Expr)) | |
4030 | then | |
4031 | return; | |
4032 | ||
6fb3c314 | 4033 | -- No check on a universal real constant. The context will eventually |
38f5559f | 4034 | -- convert it to a machine number for some target type, or report an |
4035 | -- illegality. | |
4036 | ||
4037 | elsif Nkind (Expr) = N_Real_Literal | |
4038 | and then Etype (Expr) = Universal_Real | |
4039 | then | |
4040 | return; | |
4041 | ||
6fb3c314 | 4042 | -- If the expression denotes a component of a packed boolean array, |
0577b0b1 | 4043 | -- no possible check applies. We ignore the old ACATS chestnuts that |
4044 | -- involve Boolean range True..True. | |
4045 | ||
4046 | -- Note: validity checks are generated for expressions that yield a | |
4047 | -- scalar type, when it is possible to create a value that is outside of | |
4048 | -- the type. If this is a one-bit boolean no such value exists. This is | |
4049 | -- an optimization, and it also prevents compiler blowing up during the | |
4050 | -- elaboration of improperly expanded packed array references. | |
4051 | ||
4052 | elsif Nkind (Expr) = N_Indexed_Component | |
4053 | and then Is_Bit_Packed_Array (Etype (Prefix (Expr))) | |
4054 | and then Root_Type (Etype (Expr)) = Standard_Boolean | |
4055 | then | |
4056 | return; | |
4057 | ||
9dfe12ae | 4058 | -- An annoying special case. If this is an out parameter of a scalar |
4059 | -- type, then the value is not going to be accessed, therefore it is | |
4060 | -- inappropriate to do any validity check at the call site. | |
4061 | ||
4062 | else | |
4063 | -- Only need to worry about scalar types | |
4064 | ||
4065 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 4066 | declare |
4067 | P : Node_Id; | |
4068 | N : Node_Id; | |
4069 | E : Entity_Id; | |
4070 | F : Entity_Id; | |
4071 | A : Node_Id; | |
4072 | L : List_Id; | |
4073 | ||
4074 | begin | |
4075 | -- Find actual argument (which may be a parameter association) | |
4076 | -- and the parent of the actual argument (the call statement) | |
4077 | ||
4078 | N := Expr; | |
4079 | P := Parent (Expr); | |
4080 | ||
4081 | if Nkind (P) = N_Parameter_Association then | |
4082 | N := P; | |
4083 | P := Parent (N); | |
4084 | end if; | |
4085 | ||
feff2f05 | 4086 | -- Only need to worry if we are argument of a procedure call |
4087 | -- since functions don't have out parameters. If this is an | |
4088 | -- indirect or dispatching call, get signature from the | |
4089 | -- subprogram type. | |
ee6ba406 | 4090 | |
4091 | if Nkind (P) = N_Procedure_Call_Statement then | |
4092 | L := Parameter_Associations (P); | |
9dfe12ae | 4093 | |
4094 | if Is_Entity_Name (Name (P)) then | |
4095 | E := Entity (Name (P)); | |
4096 | else | |
4097 | pragma Assert (Nkind (Name (P)) = N_Explicit_Dereference); | |
4098 | E := Etype (Name (P)); | |
4099 | end if; | |
ee6ba406 | 4100 | |
feff2f05 | 4101 | -- Only need to worry if there are indeed actuals, and if |
4102 | -- this could be a procedure call, otherwise we cannot get a | |
4103 | -- match (either we are not an argument, or the mode of the | |
4104 | -- formal is not OUT). This test also filters out the | |
4105 | -- generic case. | |
ee6ba406 | 4106 | |
4107 | if Is_Non_Empty_List (L) | |
4108 | and then Is_Subprogram (E) | |
4109 | then | |
feff2f05 | 4110 | -- This is the loop through parameters, looking for an |
4111 | -- OUT parameter for which we are the argument. | |
ee6ba406 | 4112 | |
4113 | F := First_Formal (E); | |
4114 | A := First (L); | |
ee6ba406 | 4115 | while Present (F) loop |
4116 | if Ekind (F) = E_Out_Parameter and then A = N then | |
4117 | return; | |
4118 | end if; | |
4119 | ||
4120 | Next_Formal (F); | |
4121 | Next (A); | |
4122 | end loop; | |
4123 | end if; | |
4124 | end if; | |
4125 | end; | |
4126 | end if; | |
4127 | end if; | |
4128 | ||
fa6a6949 | 4129 | -- If this is a boolean expression, only its elementary operands need |
90a07d4c | 4130 | -- checking: if they are valid, a boolean or short-circuit operation |
4131 | -- with them will be valid as well. | |
784d4230 | 4132 | |
4133 | if Base_Type (Typ) = Standard_Boolean | |
7af38999 | 4134 | and then |
fa6a6949 | 4135 | (Nkind (Expr) in N_Op or else Nkind (Expr) in N_Short_Circuit) |
784d4230 | 4136 | then |
4137 | return; | |
4138 | end if; | |
4139 | ||
0577b0b1 | 4140 | -- If we fall through, a validity check is required |
ee6ba406 | 4141 | |
4142 | Insert_Valid_Check (Expr); | |
ce7498d3 | 4143 | |
4144 | if Is_Entity_Name (Expr) | |
4145 | and then Safe_To_Capture_Value (Expr, Entity (Expr)) | |
4146 | then | |
4147 | Set_Is_Known_Valid (Entity (Expr)); | |
4148 | end if; | |
ee6ba406 | 4149 | end Ensure_Valid; |
4150 | ||
4151 | ---------------------- | |
4152 | -- Expr_Known_Valid -- | |
4153 | ---------------------- | |
4154 | ||
4155 | function Expr_Known_Valid (Expr : Node_Id) return Boolean is | |
4156 | Typ : constant Entity_Id := Etype (Expr); | |
4157 | ||
4158 | begin | |
feff2f05 | 4159 | -- Non-scalar types are always considered valid, since they never give |
4160 | -- rise to the issues of erroneous or bounded error behavior that are | |
4161 | -- the concern. In formal reference manual terms the notion of validity | |
4162 | -- only applies to scalar types. Note that even when packed arrays are | |
4163 | -- represented using modular types, they are still arrays semantically, | |
4164 | -- so they are also always valid (in particular, the unused bits can be | |
4165 | -- random rubbish without affecting the validity of the array value). | |
ee6ba406 | 4166 | |
fa814356 | 4167 | if not Is_Scalar_Type (Typ) or else Is_Packed_Array_Type (Typ) then |
ee6ba406 | 4168 | return True; |
4169 | ||
4170 | -- If no validity checking, then everything is considered valid | |
4171 | ||
4172 | elsif not Validity_Checks_On then | |
4173 | return True; | |
4174 | ||
4175 | -- Floating-point types are considered valid unless floating-point | |
4176 | -- validity checks have been specifically turned on. | |
4177 | ||
4178 | elsif Is_Floating_Point_Type (Typ) | |
4179 | and then not Validity_Check_Floating_Point | |
4180 | then | |
4181 | return True; | |
4182 | ||
feff2f05 | 4183 | -- If the expression is the value of an object that is known to be |
4184 | -- valid, then clearly the expression value itself is valid. | |
ee6ba406 | 4185 | |
4186 | elsif Is_Entity_Name (Expr) | |
4187 | and then Is_Known_Valid (Entity (Expr)) | |
4188 | then | |
4189 | return True; | |
4190 | ||
0577b0b1 | 4191 | -- References to discriminants are always considered valid. The value |
4192 | -- of a discriminant gets checked when the object is built. Within the | |
4193 | -- record, we consider it valid, and it is important to do so, since | |
4194 | -- otherwise we can try to generate bogus validity checks which | |
feff2f05 | 4195 | -- reference discriminants out of scope. Discriminants of concurrent |
4196 | -- types are excluded for the same reason. | |
0577b0b1 | 4197 | |
4198 | elsif Is_Entity_Name (Expr) | |
feff2f05 | 4199 | and then Denotes_Discriminant (Expr, Check_Concurrent => True) |
0577b0b1 | 4200 | then |
4201 | return True; | |
4202 | ||
feff2f05 | 4203 | -- If the type is one for which all values are known valid, then we are |
4204 | -- sure that the value is valid except in the slightly odd case where | |
4205 | -- the expression is a reference to a variable whose size has been | |
4206 | -- explicitly set to a value greater than the object size. | |
ee6ba406 | 4207 | |
4208 | elsif Is_Known_Valid (Typ) then | |
4209 | if Is_Entity_Name (Expr) | |
4210 | and then Ekind (Entity (Expr)) = E_Variable | |
4211 | and then Esize (Entity (Expr)) > Esize (Typ) | |
4212 | then | |
4213 | return False; | |
4214 | else | |
4215 | return True; | |
4216 | end if; | |
4217 | ||
4218 | -- Integer and character literals always have valid values, where | |
4219 | -- appropriate these will be range checked in any case. | |
4220 | ||
4221 | elsif Nkind (Expr) = N_Integer_Literal | |
4222 | or else | |
4223 | Nkind (Expr) = N_Character_Literal | |
4224 | then | |
4225 | return True; | |
4226 | ||
4227 | -- If we have a type conversion or a qualification of a known valid | |
4228 | -- value, then the result will always be valid. | |
4229 | ||
4230 | elsif Nkind (Expr) = N_Type_Conversion | |
4231 | or else | |
4232 | Nkind (Expr) = N_Qualified_Expression | |
4233 | then | |
4234 | return Expr_Known_Valid (Expression (Expr)); | |
4235 | ||
38f5559f | 4236 | -- The result of any operator is always considered valid, since we |
4237 | -- assume the necessary checks are done by the operator. For operators | |
4238 | -- on floating-point operations, we must also check when the operation | |
4239 | -- is the right-hand side of an assignment, or is an actual in a call. | |
ee6ba406 | 4240 | |
0577b0b1 | 4241 | elsif Nkind (Expr) in N_Op then |
1d90d657 | 4242 | if Is_Floating_Point_Type (Typ) |
4243 | and then Validity_Check_Floating_Point | |
4244 | and then | |
4245 | (Nkind (Parent (Expr)) = N_Assignment_Statement | |
4246 | or else Nkind (Parent (Expr)) = N_Function_Call | |
4247 | or else Nkind (Parent (Expr)) = N_Parameter_Association) | |
4248 | then | |
4249 | return False; | |
4250 | else | |
4251 | return True; | |
4252 | end if; | |
4253 | ||
feff2f05 | 4254 | -- The result of a membership test is always valid, since it is true or |
4255 | -- false, there are no other possibilities. | |
0577b0b1 | 4256 | |
4257 | elsif Nkind (Expr) in N_Membership_Test then | |
4258 | return True; | |
4259 | ||
ee6ba406 | 4260 | -- For all other cases, we do not know the expression is valid |
4261 | ||
4262 | else | |
4263 | return False; | |
4264 | end if; | |
4265 | end Expr_Known_Valid; | |
4266 | ||
9dfe12ae | 4267 | ---------------- |
4268 | -- Find_Check -- | |
4269 | ---------------- | |
4270 | ||
4271 | procedure Find_Check | |
4272 | (Expr : Node_Id; | |
4273 | Check_Type : Character; | |
4274 | Target_Type : Entity_Id; | |
4275 | Entry_OK : out Boolean; | |
4276 | Check_Num : out Nat; | |
4277 | Ent : out Entity_Id; | |
4278 | Ofs : out Uint) | |
4279 | is | |
4280 | function Within_Range_Of | |
4281 | (Target_Type : Entity_Id; | |
314a23b6 | 4282 | Check_Type : Entity_Id) return Boolean; |
9dfe12ae | 4283 | -- Given a requirement for checking a range against Target_Type, and |
4284 | -- and a range Check_Type against which a check has already been made, | |
4285 | -- determines if the check against check type is sufficient to ensure | |
4286 | -- that no check against Target_Type is required. | |
4287 | ||
4288 | --------------------- | |
4289 | -- Within_Range_Of -- | |
4290 | --------------------- | |
4291 | ||
4292 | function Within_Range_Of | |
4293 | (Target_Type : Entity_Id; | |
314a23b6 | 4294 | Check_Type : Entity_Id) return Boolean |
9dfe12ae | 4295 | is |
4296 | begin | |
4297 | if Target_Type = Check_Type then | |
4298 | return True; | |
4299 | ||
4300 | else | |
4301 | declare | |
4302 | Tlo : constant Node_Id := Type_Low_Bound (Target_Type); | |
4303 | Thi : constant Node_Id := Type_High_Bound (Target_Type); | |
4304 | Clo : constant Node_Id := Type_Low_Bound (Check_Type); | |
4305 | Chi : constant Node_Id := Type_High_Bound (Check_Type); | |
4306 | ||
4307 | begin | |
4308 | if (Tlo = Clo | |
4309 | or else (Compile_Time_Known_Value (Tlo) | |
4310 | and then | |
4311 | Compile_Time_Known_Value (Clo) | |
4312 | and then | |
4313 | Expr_Value (Clo) >= Expr_Value (Tlo))) | |
4314 | and then | |
4315 | (Thi = Chi | |
4316 | or else (Compile_Time_Known_Value (Thi) | |
4317 | and then | |
4318 | Compile_Time_Known_Value (Chi) | |
4319 | and then | |
4320 | Expr_Value (Chi) <= Expr_Value (Clo))) | |
4321 | then | |
4322 | return True; | |
4323 | else | |
4324 | return False; | |
4325 | end if; | |
4326 | end; | |
4327 | end if; | |
4328 | end Within_Range_Of; | |
4329 | ||
4330 | -- Start of processing for Find_Check | |
4331 | ||
4332 | begin | |
ed195555 | 4333 | -- Establish default, in case no entry is found |
9dfe12ae | 4334 | |
4335 | Check_Num := 0; | |
4336 | ||
4337 | -- Case of expression is simple entity reference | |
4338 | ||
4339 | if Is_Entity_Name (Expr) then | |
4340 | Ent := Entity (Expr); | |
4341 | Ofs := Uint_0; | |
4342 | ||
4343 | -- Case of expression is entity + known constant | |
4344 | ||
4345 | elsif Nkind (Expr) = N_Op_Add | |
4346 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
4347 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
4348 | then | |
4349 | Ent := Entity (Left_Opnd (Expr)); | |
4350 | Ofs := Expr_Value (Right_Opnd (Expr)); | |
4351 | ||
4352 | -- Case of expression is entity - known constant | |
4353 | ||
4354 | elsif Nkind (Expr) = N_Op_Subtract | |
4355 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
4356 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
4357 | then | |
4358 | Ent := Entity (Left_Opnd (Expr)); | |
4359 | Ofs := UI_Negate (Expr_Value (Right_Opnd (Expr))); | |
4360 | ||
4361 | -- Any other expression is not of the right form | |
4362 | ||
4363 | else | |
4364 | Ent := Empty; | |
4365 | Ofs := Uint_0; | |
4366 | Entry_OK := False; | |
4367 | return; | |
4368 | end if; | |
4369 | ||
feff2f05 | 4370 | -- Come here with expression of appropriate form, check if entity is an |
4371 | -- appropriate one for our purposes. | |
9dfe12ae | 4372 | |
4373 | if (Ekind (Ent) = E_Variable | |
cc60bd16 | 4374 | or else Is_Constant_Object (Ent)) |
9dfe12ae | 4375 | and then not Is_Library_Level_Entity (Ent) |
4376 | then | |
4377 | Entry_OK := True; | |
4378 | else | |
4379 | Entry_OK := False; | |
4380 | return; | |
4381 | end if; | |
4382 | ||
4383 | -- See if there is matching check already | |
4384 | ||
4385 | for J in reverse 1 .. Num_Saved_Checks loop | |
4386 | declare | |
4387 | SC : Saved_Check renames Saved_Checks (J); | |
4388 | ||
4389 | begin | |
4390 | if SC.Killed = False | |
4391 | and then SC.Entity = Ent | |
4392 | and then SC.Offset = Ofs | |
4393 | and then SC.Check_Type = Check_Type | |
4394 | and then Within_Range_Of (Target_Type, SC.Target_Type) | |
4395 | then | |
4396 | Check_Num := J; | |
4397 | return; | |
4398 | end if; | |
4399 | end; | |
4400 | end loop; | |
4401 | ||
4402 | -- If we fall through entry was not found | |
4403 | ||
9dfe12ae | 4404 | return; |
4405 | end Find_Check; | |
4406 | ||
4407 | --------------------------------- | |
4408 | -- Generate_Discriminant_Check -- | |
4409 | --------------------------------- | |
4410 | ||
4411 | -- Note: the code for this procedure is derived from the | |
feff2f05 | 4412 | -- Emit_Discriminant_Check Routine in trans.c. |
9dfe12ae | 4413 | |
4414 | procedure Generate_Discriminant_Check (N : Node_Id) is | |
4415 | Loc : constant Source_Ptr := Sloc (N); | |
4416 | Pref : constant Node_Id := Prefix (N); | |
4417 | Sel : constant Node_Id := Selector_Name (N); | |
4418 | ||
4419 | Orig_Comp : constant Entity_Id := | |
4420 | Original_Record_Component (Entity (Sel)); | |
4421 | -- The original component to be checked | |
4422 | ||
4423 | Discr_Fct : constant Entity_Id := | |
4424 | Discriminant_Checking_Func (Orig_Comp); | |
4425 | -- The discriminant checking function | |
4426 | ||
4427 | Discr : Entity_Id; | |
4428 | -- One discriminant to be checked in the type | |
4429 | ||
4430 | Real_Discr : Entity_Id; | |
4431 | -- Actual discriminant in the call | |
4432 | ||
4433 | Pref_Type : Entity_Id; | |
4434 | -- Type of relevant prefix (ignoring private/access stuff) | |
4435 | ||
4436 | Args : List_Id; | |
4437 | -- List of arguments for function call | |
4438 | ||
4439 | Formal : Entity_Id; | |
feff2f05 | 4440 | -- Keep track of the formal corresponding to the actual we build for |
4441 | -- each discriminant, in order to be able to perform the necessary type | |
4442 | -- conversions. | |
9dfe12ae | 4443 | |
4444 | Scomp : Node_Id; | |
4445 | -- Selected component reference for checking function argument | |
4446 | ||
4447 | begin | |
4448 | Pref_Type := Etype (Pref); | |
4449 | ||
4450 | -- Force evaluation of the prefix, so that it does not get evaluated | |
4451 | -- twice (once for the check, once for the actual reference). Such a | |
4452 | -- double evaluation is always a potential source of inefficiency, | |
4453 | -- and is functionally incorrect in the volatile case, or when the | |
4454 | -- prefix may have side-effects. An entity or a component of an | |
4455 | -- entity requires no evaluation. | |
4456 | ||
4457 | if Is_Entity_Name (Pref) then | |
4458 | if Treat_As_Volatile (Entity (Pref)) then | |
4459 | Force_Evaluation (Pref, Name_Req => True); | |
4460 | end if; | |
4461 | ||
4462 | elsif Treat_As_Volatile (Etype (Pref)) then | |
4463 | Force_Evaluation (Pref, Name_Req => True); | |
4464 | ||
4465 | elsif Nkind (Pref) = N_Selected_Component | |
4466 | and then Is_Entity_Name (Prefix (Pref)) | |
4467 | then | |
4468 | null; | |
4469 | ||
4470 | else | |
4471 | Force_Evaluation (Pref, Name_Req => True); | |
4472 | end if; | |
4473 | ||
4474 | -- For a tagged type, use the scope of the original component to | |
4475 | -- obtain the type, because ??? | |
4476 | ||
4477 | if Is_Tagged_Type (Scope (Orig_Comp)) then | |
4478 | Pref_Type := Scope (Orig_Comp); | |
4479 | ||
feff2f05 | 4480 | -- For an untagged derived type, use the discriminants of the parent |
4481 | -- which have been renamed in the derivation, possibly by a one-to-many | |
4482 | -- discriminant constraint. For non-tagged type, initially get the Etype | |
4483 | -- of the prefix | |
9dfe12ae | 4484 | |
4485 | else | |
4486 | if Is_Derived_Type (Pref_Type) | |
4487 | and then Number_Discriminants (Pref_Type) /= | |
4488 | Number_Discriminants (Etype (Base_Type (Pref_Type))) | |
4489 | then | |
4490 | Pref_Type := Etype (Base_Type (Pref_Type)); | |
4491 | end if; | |
4492 | end if; | |
4493 | ||
4494 | -- We definitely should have a checking function, This routine should | |
4495 | -- not be called if no discriminant checking function is present. | |
4496 | ||
4497 | pragma Assert (Present (Discr_Fct)); | |
4498 | ||
4499 | -- Create the list of the actual parameters for the call. This list | |
4500 | -- is the list of the discriminant fields of the record expression to | |
4501 | -- be discriminant checked. | |
4502 | ||
4503 | Args := New_List; | |
4504 | Formal := First_Formal (Discr_Fct); | |
4505 | Discr := First_Discriminant (Pref_Type); | |
4506 | while Present (Discr) loop | |
4507 | ||
4508 | -- If we have a corresponding discriminant field, and a parent | |
4509 | -- subtype is present, then we want to use the corresponding | |
4510 | -- discriminant since this is the one with the useful value. | |
4511 | ||
4512 | if Present (Corresponding_Discriminant (Discr)) | |
4513 | and then Ekind (Pref_Type) = E_Record_Type | |
4514 | and then Present (Parent_Subtype (Pref_Type)) | |
4515 | then | |
4516 | Real_Discr := Corresponding_Discriminant (Discr); | |
4517 | else | |
4518 | Real_Discr := Discr; | |
4519 | end if; | |
4520 | ||
4521 | -- Construct the reference to the discriminant | |
4522 | ||
4523 | Scomp := | |
4524 | Make_Selected_Component (Loc, | |
4525 | Prefix => | |
4526 | Unchecked_Convert_To (Pref_Type, | |
4527 | Duplicate_Subexpr (Pref)), | |
4528 | Selector_Name => New_Occurrence_Of (Real_Discr, Loc)); | |
4529 | ||
4530 | -- Manually analyze and resolve this selected component. We really | |
4531 | -- want it just as it appears above, and do not want the expander | |
feff2f05 | 4532 | -- playing discriminal games etc with this reference. Then we append |
4533 | -- the argument to the list we are gathering. | |
9dfe12ae | 4534 | |
4535 | Set_Etype (Scomp, Etype (Real_Discr)); | |
4536 | Set_Analyzed (Scomp, True); | |
4537 | Append_To (Args, Convert_To (Etype (Formal), Scomp)); | |
4538 | ||
4539 | Next_Formal_With_Extras (Formal); | |
4540 | Next_Discriminant (Discr); | |
4541 | end loop; | |
4542 | ||
4543 | -- Now build and insert the call | |
4544 | ||
4545 | Insert_Action (N, | |
4546 | Make_Raise_Constraint_Error (Loc, | |
4547 | Condition => | |
4548 | Make_Function_Call (Loc, | |
4549 | Name => New_Occurrence_Of (Discr_Fct, Loc), | |
4550 | Parameter_Associations => Args), | |
4551 | Reason => CE_Discriminant_Check_Failed)); | |
4552 | end Generate_Discriminant_Check; | |
4553 | ||
5c99c290 | 4554 | --------------------------- |
4555 | -- Generate_Index_Checks -- | |
4556 | --------------------------- | |
9dfe12ae | 4557 | |
4558 | procedure Generate_Index_Checks (N : Node_Id) is | |
05f3e139 | 4559 | |
4560 | function Entity_Of_Prefix return Entity_Id; | |
4561 | -- Returns the entity of the prefix of N (or Empty if not found) | |
4562 | ||
3f42e2a7 | 4563 | ---------------------- |
4564 | -- Entity_Of_Prefix -- | |
4565 | ---------------------- | |
4566 | ||
05f3e139 | 4567 | function Entity_Of_Prefix return Entity_Id is |
e5d38095 | 4568 | P : Node_Id; |
4569 | ||
05f3e139 | 4570 | begin |
e5d38095 | 4571 | P := Prefix (N); |
05f3e139 | 4572 | while not Is_Entity_Name (P) loop |
4573 | if not Nkind_In (P, N_Selected_Component, | |
4574 | N_Indexed_Component) | |
4575 | then | |
4576 | return Empty; | |
4577 | end if; | |
4578 | ||
4579 | P := Prefix (P); | |
4580 | end loop; | |
4581 | ||
4582 | return Entity (P); | |
4583 | end Entity_Of_Prefix; | |
4584 | ||
4585 | -- Local variables | |
4586 | ||
4587 | Loc : constant Source_Ptr := Sloc (N); | |
4588 | A : constant Node_Id := Prefix (N); | |
4589 | A_Ent : constant Entity_Id := Entity_Of_Prefix; | |
4590 | Sub : Node_Id; | |
9dfe12ae | 4591 | |
3f42e2a7 | 4592 | -- Start of processing for Generate_Index_Checks |
4593 | ||
9dfe12ae | 4594 | begin |
05f3e139 | 4595 | -- Ignore call if the prefix is not an array since we have a serious |
4596 | -- error in the sources. Ignore it also if index checks are suppressed | |
4597 | -- for array object or type. | |
0577b0b1 | 4598 | |
05f3e139 | 4599 | if not Is_Array_Type (Etype (A)) |
4600 | or else (Present (A_Ent) | |
e5d38095 | 4601 | and then Index_Checks_Suppressed (A_Ent)) |
0577b0b1 | 4602 | or else Index_Checks_Suppressed (Etype (A)) |
4603 | then | |
4604 | return; | |
4605 | end if; | |
4606 | ||
05f3e139 | 4607 | -- Generate a raise of constraint error with the appropriate reason and |
4608 | -- a condition of the form: | |
4609 | ||
3f42e2a7 | 4610 | -- Base_Type (Sub) not in Array'Range (Subscript) |
05f3e139 | 4611 | |
4612 | -- Note that the reason we generate the conversion to the base type here | |
4613 | -- is that we definitely want the range check to take place, even if it | |
4614 | -- looks like the subtype is OK. Optimization considerations that allow | |
4615 | -- us to omit the check have already been taken into account in the | |
4616 | -- setting of the Do_Range_Check flag earlier on. | |
0577b0b1 | 4617 | |
9dfe12ae | 4618 | Sub := First (Expressions (N)); |
05f3e139 | 4619 | |
4620 | -- Handle string literals | |
4621 | ||
4622 | if Ekind (Etype (A)) = E_String_Literal_Subtype then | |
9dfe12ae | 4623 | if Do_Range_Check (Sub) then |
4624 | Set_Do_Range_Check (Sub, False); | |
4625 | ||
05f3e139 | 4626 | -- For string literals we obtain the bounds of the string from the |
4627 | -- associated subtype. | |
9dfe12ae | 4628 | |
05f3e139 | 4629 | Insert_Action (N, |
4630 | Make_Raise_Constraint_Error (Loc, | |
4631 | Condition => | |
4632 | Make_Not_In (Loc, | |
4633 | Left_Opnd => | |
4634 | Convert_To (Base_Type (Etype (Sub)), | |
4635 | Duplicate_Subexpr_Move_Checks (Sub)), | |
4636 | Right_Opnd => | |
4637 | Make_Attribute_Reference (Loc, | |
3f42e2a7 | 4638 | Prefix => New_Reference_To (Etype (A), Loc), |
05f3e139 | 4639 | Attribute_Name => Name_Range)), |
4640 | Reason => CE_Index_Check_Failed)); | |
4641 | end if; | |
9dfe12ae | 4642 | |
05f3e139 | 4643 | -- General case |
9dfe12ae | 4644 | |
05f3e139 | 4645 | else |
4646 | declare | |
4647 | A_Idx : Node_Id := Empty; | |
4648 | A_Range : Node_Id; | |
4649 | Ind : Nat; | |
4650 | Num : List_Id; | |
4651 | Range_N : Node_Id; | |
9dfe12ae | 4652 | |
05f3e139 | 4653 | begin |
4654 | A_Idx := First_Index (Etype (A)); | |
4655 | Ind := 1; | |
4656 | while Present (Sub) loop | |
4657 | if Do_Range_Check (Sub) then | |
4658 | Set_Do_Range_Check (Sub, False); | |
9dfe12ae | 4659 | |
05f3e139 | 4660 | -- Force evaluation except for the case of a simple name of |
4661 | -- a non-volatile entity. | |
9dfe12ae | 4662 | |
05f3e139 | 4663 | if not Is_Entity_Name (Sub) |
4664 | or else Treat_As_Volatile (Entity (Sub)) | |
4665 | then | |
4666 | Force_Evaluation (Sub); | |
4667 | end if; | |
9dfe12ae | 4668 | |
05f3e139 | 4669 | if Nkind (A_Idx) = N_Range then |
4670 | A_Range := A_Idx; | |
4671 | ||
4672 | elsif Nkind (A_Idx) = N_Identifier | |
4673 | or else Nkind (A_Idx) = N_Expanded_Name | |
4674 | then | |
4675 | A_Range := Scalar_Range (Entity (A_Idx)); | |
4676 | ||
4677 | else pragma Assert (Nkind (A_Idx) = N_Subtype_Indication); | |
4678 | A_Range := Range_Expression (Constraint (A_Idx)); | |
4679 | end if; | |
4680 | ||
4681 | -- For array objects with constant bounds we can generate | |
4682 | -- the index check using the bounds of the type of the index | |
4683 | ||
4684 | if Present (A_Ent) | |
4685 | and then Ekind (A_Ent) = E_Variable | |
4686 | and then Is_Constant_Bound (Low_Bound (A_Range)) | |
4687 | and then Is_Constant_Bound (High_Bound (A_Range)) | |
4688 | then | |
4689 | Range_N := | |
4690 | Make_Attribute_Reference (Loc, | |
3f42e2a7 | 4691 | Prefix => |
4692 | New_Reference_To (Etype (A_Idx), Loc), | |
05f3e139 | 4693 | Attribute_Name => Name_Range); |
4694 | ||
4695 | -- For arrays with non-constant bounds we cannot generate | |
4696 | -- the index check using the bounds of the type of the index | |
4697 | -- since it may reference discriminants of some enclosing | |
4698 | -- type. We obtain the bounds directly from the prefix | |
4699 | -- object. | |
4700 | ||
4701 | else | |
4702 | if Ind = 1 then | |
4703 | Num := No_List; | |
4704 | else | |
4705 | Num := New_List (Make_Integer_Literal (Loc, Ind)); | |
4706 | end if; | |
4707 | ||
4708 | Range_N := | |
4709 | Make_Attribute_Reference (Loc, | |
4710 | Prefix => | |
4711 | Duplicate_Subexpr_Move_Checks (A, Name_Req => True), | |
4712 | Attribute_Name => Name_Range, | |
4713 | Expressions => Num); | |
4714 | end if; | |
4715 | ||
4716 | Insert_Action (N, | |
4717 | Make_Raise_Constraint_Error (Loc, | |
4718 | Condition => | |
4719 | Make_Not_In (Loc, | |
4720 | Left_Opnd => | |
4721 | Convert_To (Base_Type (Etype (Sub)), | |
4722 | Duplicate_Subexpr_Move_Checks (Sub)), | |
4723 | Right_Opnd => Range_N), | |
4724 | Reason => CE_Index_Check_Failed)); | |
4725 | end if; | |
4726 | ||
4727 | A_Idx := Next_Index (A_Idx); | |
4728 | Ind := Ind + 1; | |
4729 | Next (Sub); | |
4730 | end loop; | |
4731 | end; | |
4732 | end if; | |
9dfe12ae | 4733 | end Generate_Index_Checks; |
4734 | ||
4735 | -------------------------- | |
4736 | -- Generate_Range_Check -- | |
4737 | -------------------------- | |
4738 | ||
4739 | procedure Generate_Range_Check | |
4740 | (N : Node_Id; | |
4741 | Target_Type : Entity_Id; | |
4742 | Reason : RT_Exception_Code) | |
4743 | is | |
4744 | Loc : constant Source_Ptr := Sloc (N); | |
4745 | Source_Type : constant Entity_Id := Etype (N); | |
4746 | Source_Base_Type : constant Entity_Id := Base_Type (Source_Type); | |
4747 | Target_Base_Type : constant Entity_Id := Base_Type (Target_Type); | |
4748 | ||
4749 | begin | |
feff2f05 | 4750 | -- First special case, if the source type is already within the range |
4751 | -- of the target type, then no check is needed (probably we should have | |
4752 | -- stopped Do_Range_Check from being set in the first place, but better | |
4753 | -- late than later in preventing junk code! | |
9dfe12ae | 4754 | |
feff2f05 | 4755 | -- We do NOT apply this if the source node is a literal, since in this |
4756 | -- case the literal has already been labeled as having the subtype of | |
4757 | -- the target. | |
9dfe12ae | 4758 | |
7a1dabb3 | 4759 | if In_Subrange_Of (Source_Type, Target_Type) |
9dfe12ae | 4760 | and then not |
4761 | (Nkind (N) = N_Integer_Literal | |
4762 | or else | |
4763 | Nkind (N) = N_Real_Literal | |
4764 | or else | |
4765 | Nkind (N) = N_Character_Literal | |
4766 | or else | |
4767 | (Is_Entity_Name (N) | |
4768 | and then Ekind (Entity (N)) = E_Enumeration_Literal)) | |
4769 | then | |
4770 | return; | |
4771 | end if; | |
4772 | ||
4773 | -- We need a check, so force evaluation of the node, so that it does | |
4774 | -- not get evaluated twice (once for the check, once for the actual | |
4775 | -- reference). Such a double evaluation is always a potential source | |
4776 | -- of inefficiency, and is functionally incorrect in the volatile case. | |
4777 | ||
4778 | if not Is_Entity_Name (N) | |
4779 | or else Treat_As_Volatile (Entity (N)) | |
4780 | then | |
4781 | Force_Evaluation (N); | |
4782 | end if; | |
4783 | ||
feff2f05 | 4784 | -- The easiest case is when Source_Base_Type and Target_Base_Type are |
4785 | -- the same since in this case we can simply do a direct check of the | |
4786 | -- value of N against the bounds of Target_Type. | |
9dfe12ae | 4787 | |
4788 | -- [constraint_error when N not in Target_Type] | |
4789 | ||
4790 | -- Note: this is by far the most common case, for example all cases of | |
4791 | -- checks on the RHS of assignments are in this category, but not all | |
4792 | -- cases are like this. Notably conversions can involve two types. | |
4793 | ||
4794 | if Source_Base_Type = Target_Base_Type then | |
4795 | Insert_Action (N, | |
4796 | Make_Raise_Constraint_Error (Loc, | |
4797 | Condition => | |
4798 | Make_Not_In (Loc, | |
4799 | Left_Opnd => Duplicate_Subexpr (N), | |
4800 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
4801 | Reason => Reason)); | |
4802 | ||
4803 | -- Next test for the case where the target type is within the bounds | |
4804 | -- of the base type of the source type, since in this case we can | |
4805 | -- simply convert these bounds to the base type of T to do the test. | |
4806 | ||
4807 | -- [constraint_error when N not in | |
4808 | -- Source_Base_Type (Target_Type'First) | |
4809 | -- .. | |
4810 | -- Source_Base_Type(Target_Type'Last))] | |
4811 | ||
f2a06be9 | 4812 | -- The conversions will always work and need no check |
9dfe12ae | 4813 | |
a9b57347 | 4814 | -- Unchecked_Convert_To is used instead of Convert_To to handle the case |
4815 | -- of converting from an enumeration value to an integer type, such as | |
4816 | -- occurs for the case of generating a range check on Enum'Val(Exp) | |
4817 | -- (which used to be handled by gigi). This is OK, since the conversion | |
4818 | -- itself does not require a check. | |
4819 | ||
7a1dabb3 | 4820 | elsif In_Subrange_Of (Target_Type, Source_Base_Type) then |
9dfe12ae | 4821 | Insert_Action (N, |
4822 | Make_Raise_Constraint_Error (Loc, | |
4823 | Condition => | |
4824 | Make_Not_In (Loc, | |
4825 | Left_Opnd => Duplicate_Subexpr (N), | |
4826 | ||
4827 | Right_Opnd => | |
4828 | Make_Range (Loc, | |
4829 | Low_Bound => | |
a9b57347 | 4830 | Unchecked_Convert_To (Source_Base_Type, |
9dfe12ae | 4831 | Make_Attribute_Reference (Loc, |
4832 | Prefix => | |
4833 | New_Occurrence_Of (Target_Type, Loc), | |
4834 | Attribute_Name => Name_First)), | |
4835 | ||
4836 | High_Bound => | |
a9b57347 | 4837 | Unchecked_Convert_To (Source_Base_Type, |
9dfe12ae | 4838 | Make_Attribute_Reference (Loc, |
4839 | Prefix => | |
4840 | New_Occurrence_Of (Target_Type, Loc), | |
4841 | Attribute_Name => Name_Last)))), | |
4842 | Reason => Reason)); | |
4843 | ||
feff2f05 | 4844 | -- Note that at this stage we now that the Target_Base_Type is not in |
4845 | -- the range of the Source_Base_Type (since even the Target_Type itself | |
4846 | -- is not in this range). It could still be the case that Source_Type is | |
4847 | -- in range of the target base type since we have not checked that case. | |
9dfe12ae | 4848 | |
feff2f05 | 4849 | -- If that is the case, we can freely convert the source to the target, |
4850 | -- and then test the target result against the bounds. | |
9dfe12ae | 4851 | |
7a1dabb3 | 4852 | elsif In_Subrange_Of (Source_Type, Target_Base_Type) then |
9dfe12ae | 4853 | |
feff2f05 | 4854 | -- We make a temporary to hold the value of the converted value |
4855 | -- (converted to the base type), and then we will do the test against | |
4856 | -- this temporary. | |
9dfe12ae | 4857 | |
4858 | -- Tnn : constant Target_Base_Type := Target_Base_Type (N); | |
4859 | -- [constraint_error when Tnn not in Target_Type] | |
4860 | ||
4861 | -- Then the conversion itself is replaced by an occurrence of Tnn | |
4862 | ||
4863 | declare | |
46eb6933 | 4864 | Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
9dfe12ae | 4865 | |
4866 | begin | |
4867 | Insert_Actions (N, New_List ( | |
4868 | Make_Object_Declaration (Loc, | |
4869 | Defining_Identifier => Tnn, | |
4870 | Object_Definition => | |
4871 | New_Occurrence_Of (Target_Base_Type, Loc), | |
4872 | Constant_Present => True, | |
4873 | Expression => | |
4874 | Make_Type_Conversion (Loc, | |
4875 | Subtype_Mark => New_Occurrence_Of (Target_Base_Type, Loc), | |
4876 | Expression => Duplicate_Subexpr (N))), | |
4877 | ||
4878 | Make_Raise_Constraint_Error (Loc, | |
4879 | Condition => | |
4880 | Make_Not_In (Loc, | |
4881 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
4882 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
4883 | ||
4884 | Reason => Reason))); | |
4885 | ||
4886 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
2af58f67 | 4887 | |
4888 | -- Set the type of N, because the declaration for Tnn might not | |
4889 | -- be analyzed yet, as is the case if N appears within a record | |
4890 | -- declaration, as a discriminant constraint or expression. | |
4891 | ||
4892 | Set_Etype (N, Target_Base_Type); | |
9dfe12ae | 4893 | end; |
4894 | ||
4895 | -- At this stage, we know that we have two scalar types, which are | |
4896 | -- directly convertible, and where neither scalar type has a base | |
4897 | -- range that is in the range of the other scalar type. | |
4898 | ||
4899 | -- The only way this can happen is with a signed and unsigned type. | |
4900 | -- So test for these two cases: | |
4901 | ||
4902 | else | |
4903 | -- Case of the source is unsigned and the target is signed | |
4904 | ||
4905 | if Is_Unsigned_Type (Source_Base_Type) | |
4906 | and then not Is_Unsigned_Type (Target_Base_Type) | |
4907 | then | |
4908 | -- If the source is unsigned and the target is signed, then we | |
4909 | -- know that the source is not shorter than the target (otherwise | |
4910 | -- the source base type would be in the target base type range). | |
4911 | ||
feff2f05 | 4912 | -- In other words, the unsigned type is either the same size as |
4913 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 4914 | |
4915 | pragma Assert | |
4916 | (Esize (Source_Base_Type) >= Esize (Target_Base_Type)); | |
4917 | ||
4918 | -- We only need to check the low bound if the low bound of the | |
4919 | -- target type is non-negative. If the low bound of the target | |
4920 | -- type is negative, then we know that we will fit fine. | |
4921 | ||
4922 | -- If the high bound of the target type is negative, then we | |
4923 | -- know we have a constraint error, since we can't possibly | |
4924 | -- have a negative source. | |
4925 | ||
4926 | -- With these two checks out of the way, we can do the check | |
4927 | -- using the source type safely | |
4928 | ||
4929 | -- This is definitely the most annoying case! | |
4930 | ||
4931 | -- [constraint_error | |
4932 | -- when (Target_Type'First >= 0 | |
4933 | -- and then | |
4934 | -- N < Source_Base_Type (Target_Type'First)) | |
4935 | -- or else Target_Type'Last < 0 | |
4936 | -- or else N > Source_Base_Type (Target_Type'Last)]; | |
4937 | ||
4938 | -- We turn off all checks since we know that the conversions | |
4939 | -- will work fine, given the guards for negative values. | |
4940 | ||
4941 | Insert_Action (N, | |
4942 | Make_Raise_Constraint_Error (Loc, | |
4943 | Condition => | |
4944 | Make_Or_Else (Loc, | |
4945 | Make_Or_Else (Loc, | |
4946 | Left_Opnd => | |
4947 | Make_And_Then (Loc, | |
4948 | Left_Opnd => Make_Op_Ge (Loc, | |
4949 | Left_Opnd => | |
4950 | Make_Attribute_Reference (Loc, | |
4951 | Prefix => | |
4952 | New_Occurrence_Of (Target_Type, Loc), | |
4953 | Attribute_Name => Name_First), | |
4954 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
4955 | ||
4956 | Right_Opnd => | |
4957 | Make_Op_Lt (Loc, | |
4958 | Left_Opnd => Duplicate_Subexpr (N), | |
4959 | Right_Opnd => | |
4960 | Convert_To (Source_Base_Type, | |
4961 | Make_Attribute_Reference (Loc, | |
4962 | Prefix => | |
4963 | New_Occurrence_Of (Target_Type, Loc), | |
4964 | Attribute_Name => Name_First)))), | |
4965 | ||
4966 | Right_Opnd => | |
4967 | Make_Op_Lt (Loc, | |
4968 | Left_Opnd => | |
4969 | Make_Attribute_Reference (Loc, | |
4970 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
4971 | Attribute_Name => Name_Last), | |
4972 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0))), | |
4973 | ||
4974 | Right_Opnd => | |
4975 | Make_Op_Gt (Loc, | |
4976 | Left_Opnd => Duplicate_Subexpr (N), | |
4977 | Right_Opnd => | |
4978 | Convert_To (Source_Base_Type, | |
4979 | Make_Attribute_Reference (Loc, | |
4980 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
4981 | Attribute_Name => Name_Last)))), | |
4982 | ||
4983 | Reason => Reason), | |
4984 | Suppress => All_Checks); | |
4985 | ||
4986 | -- Only remaining possibility is that the source is signed and | |
fc75802a | 4987 | -- the target is unsigned. |
9dfe12ae | 4988 | |
4989 | else | |
4990 | pragma Assert (not Is_Unsigned_Type (Source_Base_Type) | |
4991 | and then Is_Unsigned_Type (Target_Base_Type)); | |
4992 | ||
feff2f05 | 4993 | -- If the source is signed and the target is unsigned, then we |
4994 | -- know that the target is not shorter than the source (otherwise | |
4995 | -- the target base type would be in the source base type range). | |
9dfe12ae | 4996 | |
feff2f05 | 4997 | -- In other words, the unsigned type is either the same size as |
4998 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 4999 | |
feff2f05 | 5000 | -- Clearly we have an error if the source value is negative since |
5001 | -- no unsigned type can have negative values. If the source type | |
5002 | -- is non-negative, then the check can be done using the target | |
5003 | -- type. | |
9dfe12ae | 5004 | |
5005 | -- Tnn : constant Target_Base_Type (N) := Target_Type; | |
5006 | ||
5007 | -- [constraint_error | |
5008 | -- when N < 0 or else Tnn not in Target_Type]; | |
5009 | ||
feff2f05 | 5010 | -- We turn off all checks for the conversion of N to the target |
5011 | -- base type, since we generate the explicit check to ensure that | |
5012 | -- the value is non-negative | |
9dfe12ae | 5013 | |
5014 | declare | |
46eb6933 | 5015 | Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
9dfe12ae | 5016 | |
5017 | begin | |
5018 | Insert_Actions (N, New_List ( | |
5019 | Make_Object_Declaration (Loc, | |
5020 | Defining_Identifier => Tnn, | |
5021 | Object_Definition => | |
5022 | New_Occurrence_Of (Target_Base_Type, Loc), | |
5023 | Constant_Present => True, | |
5024 | Expression => | |
a9b57347 | 5025 | Make_Unchecked_Type_Conversion (Loc, |
9dfe12ae | 5026 | Subtype_Mark => |
5027 | New_Occurrence_Of (Target_Base_Type, Loc), | |
5028 | Expression => Duplicate_Subexpr (N))), | |
5029 | ||
5030 | Make_Raise_Constraint_Error (Loc, | |
5031 | Condition => | |
5032 | Make_Or_Else (Loc, | |
5033 | Left_Opnd => | |
5034 | Make_Op_Lt (Loc, | |
5035 | Left_Opnd => Duplicate_Subexpr (N), | |
5036 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
5037 | ||
5038 | Right_Opnd => | |
5039 | Make_Not_In (Loc, | |
5040 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
5041 | Right_Opnd => | |
5042 | New_Occurrence_Of (Target_Type, Loc))), | |
5043 | ||
5044 | Reason => Reason)), | |
5045 | Suppress => All_Checks); | |
5046 | ||
feff2f05 | 5047 | -- Set the Etype explicitly, because Insert_Actions may have |
5048 | -- placed the declaration in the freeze list for an enclosing | |
5049 | -- construct, and thus it is not analyzed yet. | |
9dfe12ae | 5050 | |
5051 | Set_Etype (Tnn, Target_Base_Type); | |
5052 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
5053 | end; | |
5054 | end if; | |
5055 | end if; | |
5056 | end Generate_Range_Check; | |
5057 | ||
2af58f67 | 5058 | ------------------ |
5059 | -- Get_Check_Id -- | |
5060 | ------------------ | |
5061 | ||
5062 | function Get_Check_Id (N : Name_Id) return Check_Id is | |
5063 | begin | |
5064 | -- For standard check name, we can do a direct computation | |
5065 | ||
5066 | if N in First_Check_Name .. Last_Check_Name then | |
5067 | return Check_Id (N - (First_Check_Name - 1)); | |
5068 | ||
5069 | -- For non-standard names added by pragma Check_Name, search table | |
5070 | ||
5071 | else | |
5072 | for J in All_Checks + 1 .. Check_Names.Last loop | |
5073 | if Check_Names.Table (J) = N then | |
5074 | return J; | |
5075 | end if; | |
5076 | end loop; | |
5077 | end if; | |
5078 | ||
5079 | -- No matching name found | |
5080 | ||
5081 | return No_Check_Id; | |
5082 | end Get_Check_Id; | |
5083 | ||
ee6ba406 | 5084 | --------------------- |
5085 | -- Get_Discriminal -- | |
5086 | --------------------- | |
5087 | ||
5088 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is | |
5089 | Loc : constant Source_Ptr := Sloc (E); | |
5090 | D : Entity_Id; | |
5091 | Sc : Entity_Id; | |
5092 | ||
5093 | begin | |
0577b0b1 | 5094 | -- The bound can be a bona fide parameter of a protected operation, |
5095 | -- rather than a prival encoded as an in-parameter. | |
5096 | ||
5097 | if No (Discriminal_Link (Entity (Bound))) then | |
5098 | return Bound; | |
5099 | end if; | |
5100 | ||
2af58f67 | 5101 | -- Climb the scope stack looking for an enclosing protected type. If |
5102 | -- we run out of scopes, return the bound itself. | |
5103 | ||
5104 | Sc := Scope (E); | |
5105 | while Present (Sc) loop | |
5106 | if Sc = Standard_Standard then | |
5107 | return Bound; | |
5108 | ||
5109 | elsif Ekind (Sc) = E_Protected_Type then | |
5110 | exit; | |
5111 | end if; | |
5112 | ||
5113 | Sc := Scope (Sc); | |
5114 | end loop; | |
5115 | ||
ee6ba406 | 5116 | D := First_Discriminant (Sc); |
2af58f67 | 5117 | while Present (D) loop |
5118 | if Chars (D) = Chars (Bound) then | |
5119 | return New_Occurrence_Of (Discriminal (D), Loc); | |
5120 | end if; | |
ee6ba406 | 5121 | |
ee6ba406 | 5122 | Next_Discriminant (D); |
5123 | end loop; | |
5124 | ||
2af58f67 | 5125 | return Bound; |
ee6ba406 | 5126 | end Get_Discriminal; |
5127 | ||
2af58f67 | 5128 | ---------------------- |
5129 | -- Get_Range_Checks -- | |
5130 | ---------------------- | |
5131 | ||
5132 | function Get_Range_Checks | |
5133 | (Ck_Node : Node_Id; | |
5134 | Target_Typ : Entity_Id; | |
5135 | Source_Typ : Entity_Id := Empty; | |
5136 | Warn_Node : Node_Id := Empty) return Check_Result | |
5137 | is | |
5138 | begin | |
5139 | return Selected_Range_Checks | |
5140 | (Ck_Node, Target_Typ, Source_Typ, Warn_Node); | |
5141 | end Get_Range_Checks; | |
5142 | ||
ee6ba406 | 5143 | ------------------ |
5144 | -- Guard_Access -- | |
5145 | ------------------ | |
5146 | ||
5147 | function Guard_Access | |
5148 | (Cond : Node_Id; | |
5149 | Loc : Source_Ptr; | |
314a23b6 | 5150 | Ck_Node : Node_Id) return Node_Id |
ee6ba406 | 5151 | is |
5152 | begin | |
5153 | if Nkind (Cond) = N_Or_Else then | |
5154 | Set_Paren_Count (Cond, 1); | |
5155 | end if; | |
5156 | ||
5157 | if Nkind (Ck_Node) = N_Allocator then | |
5158 | return Cond; | |
5159 | else | |
5160 | return | |
5161 | Make_And_Then (Loc, | |
5162 | Left_Opnd => | |
5163 | Make_Op_Ne (Loc, | |
9dfe12ae | 5164 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), |
ee6ba406 | 5165 | Right_Opnd => Make_Null (Loc)), |
5166 | Right_Opnd => Cond); | |
5167 | end if; | |
5168 | end Guard_Access; | |
5169 | ||
5170 | ----------------------------- | |
5171 | -- Index_Checks_Suppressed -- | |
5172 | ----------------------------- | |
5173 | ||
5174 | function Index_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5175 | begin | |
9dfe12ae | 5176 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
5177 | return Is_Check_Suppressed (E, Index_Check); | |
5178 | else | |
5179 | return Scope_Suppress (Index_Check); | |
5180 | end if; | |
ee6ba406 | 5181 | end Index_Checks_Suppressed; |
5182 | ||
5183 | ---------------- | |
5184 | -- Initialize -- | |
5185 | ---------------- | |
5186 | ||
5187 | procedure Initialize is | |
5188 | begin | |
5189 | for J in Determine_Range_Cache_N'Range loop | |
5190 | Determine_Range_Cache_N (J) := Empty; | |
5191 | end loop; | |
2af58f67 | 5192 | |
5193 | Check_Names.Init; | |
5194 | ||
5195 | for J in Int range 1 .. All_Checks loop | |
5196 | Check_Names.Append (Name_Id (Int (First_Check_Name) + J - 1)); | |
5197 | end loop; | |
ee6ba406 | 5198 | end Initialize; |
5199 | ||
5200 | ------------------------- | |
5201 | -- Insert_Range_Checks -- | |
5202 | ------------------------- | |
5203 | ||
5204 | procedure Insert_Range_Checks | |
5205 | (Checks : Check_Result; | |
5206 | Node : Node_Id; | |
5207 | Suppress_Typ : Entity_Id; | |
5208 | Static_Sloc : Source_Ptr := No_Location; | |
5209 | Flag_Node : Node_Id := Empty; | |
5210 | Do_Before : Boolean := False) | |
5211 | is | |
5212 | Internal_Flag_Node : Node_Id := Flag_Node; | |
5213 | Internal_Static_Sloc : Source_Ptr := Static_Sloc; | |
5214 | ||
5215 | Check_Node : Node_Id; | |
5216 | Checks_On : constant Boolean := | |
5217 | (not Index_Checks_Suppressed (Suppress_Typ)) | |
5218 | or else | |
5219 | (not Range_Checks_Suppressed (Suppress_Typ)); | |
5220 | ||
5221 | begin | |
feff2f05 | 5222 | -- For now we just return if Checks_On is false, however this should be |
5223 | -- enhanced to check for an always True value in the condition and to | |
5224 | -- generate a compilation warning??? | |
ee6ba406 | 5225 | |
5226 | if not Expander_Active or else not Checks_On then | |
5227 | return; | |
5228 | end if; | |
5229 | ||
5230 | if Static_Sloc = No_Location then | |
5231 | Internal_Static_Sloc := Sloc (Node); | |
5232 | end if; | |
5233 | ||
5234 | if No (Flag_Node) then | |
5235 | Internal_Flag_Node := Node; | |
5236 | end if; | |
5237 | ||
5238 | for J in 1 .. 2 loop | |
5239 | exit when No (Checks (J)); | |
5240 | ||
5241 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
5242 | and then Present (Condition (Checks (J))) | |
5243 | then | |
5244 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
5245 | Check_Node := Checks (J); | |
5246 | Mark_Rewrite_Insertion (Check_Node); | |
5247 | ||
5248 | if Do_Before then | |
5249 | Insert_Before_And_Analyze (Node, Check_Node); | |
5250 | else | |
5251 | Insert_After_And_Analyze (Node, Check_Node); | |
5252 | end if; | |
5253 | ||
5254 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
5255 | end if; | |
5256 | ||
5257 | else | |
5258 | Check_Node := | |
f15731c4 | 5259 | Make_Raise_Constraint_Error (Internal_Static_Sloc, |
5260 | Reason => CE_Range_Check_Failed); | |
ee6ba406 | 5261 | Mark_Rewrite_Insertion (Check_Node); |
5262 | ||
5263 | if Do_Before then | |
5264 | Insert_Before_And_Analyze (Node, Check_Node); | |
5265 | else | |
5266 | Insert_After_And_Analyze (Node, Check_Node); | |
5267 | end if; | |
5268 | end if; | |
5269 | end loop; | |
5270 | end Insert_Range_Checks; | |
5271 | ||
5272 | ------------------------ | |
5273 | -- Insert_Valid_Check -- | |
5274 | ------------------------ | |
5275 | ||
5276 | procedure Insert_Valid_Check (Expr : Node_Id) is | |
5277 | Loc : constant Source_Ptr := Sloc (Expr); | |
8b718dab | 5278 | Exp : Node_Id; |
ee6ba406 | 5279 | |
5280 | begin | |
06ad5813 | 5281 | -- Do not insert if checks off, or if not checking validity or |
5282 | -- if expression is known to be valid | |
ee6ba406 | 5283 | |
0577b0b1 | 5284 | if not Validity_Checks_On |
5285 | or else Range_Or_Validity_Checks_Suppressed (Expr) | |
06ad5813 | 5286 | or else Expr_Known_Valid (Expr) |
ee6ba406 | 5287 | then |
8b718dab | 5288 | return; |
5289 | end if; | |
ee6ba406 | 5290 | |
8b718dab | 5291 | -- If we have a checked conversion, then validity check applies to |
5292 | -- the expression inside the conversion, not the result, since if | |
5293 | -- the expression inside is valid, then so is the conversion result. | |
ee6ba406 | 5294 | |
8b718dab | 5295 | Exp := Expr; |
5296 | while Nkind (Exp) = N_Type_Conversion loop | |
5297 | Exp := Expression (Exp); | |
5298 | end loop; | |
5299 | ||
0577b0b1 | 5300 | -- We are about to insert the validity check for Exp. We save and |
5301 | -- reset the Do_Range_Check flag over this validity check, and then | |
5302 | -- put it back for the final original reference (Exp may be rewritten). | |
5303 | ||
5304 | declare | |
5305 | DRC : constant Boolean := Do_Range_Check (Exp); | |
05fcfafb | 5306 | |
0577b0b1 | 5307 | begin |
5308 | Set_Do_Range_Check (Exp, False); | |
5309 | ||
06ad5813 | 5310 | -- Force evaluation to avoid multiple reads for atomic/volatile |
5311 | ||
5312 | if Is_Entity_Name (Exp) | |
5313 | and then Is_Volatile (Entity (Exp)) | |
5314 | then | |
5315 | Force_Evaluation (Exp, Name_Req => True); | |
5316 | end if; | |
5317 | ||
0577b0b1 | 5318 | -- Insert the validity check. Note that we do this with validity |
5319 | -- checks turned off, to avoid recursion, we do not want validity | |
5320 | -- checks on the validity checking code itself! | |
5321 | ||
5322 | Insert_Action | |
5323 | (Expr, | |
5324 | Make_Raise_Constraint_Error (Loc, | |
5325 | Condition => | |
5326 | Make_Op_Not (Loc, | |
5327 | Right_Opnd => | |
5328 | Make_Attribute_Reference (Loc, | |
5329 | Prefix => | |
5330 | Duplicate_Subexpr_No_Checks (Exp, Name_Req => True), | |
5331 | Attribute_Name => Name_Valid)), | |
5332 | Reason => CE_Invalid_Data), | |
5333 | Suppress => Validity_Check); | |
5334 | ||
6fb3c314 | 5335 | -- If the expression is a reference to an element of a bit-packed |
0577b0b1 | 5336 | -- array, then it is rewritten as a renaming declaration. If the |
5337 | -- expression is an actual in a call, it has not been expanded, | |
5338 | -- waiting for the proper point at which to do it. The same happens | |
5339 | -- with renamings, so that we have to force the expansion now. This | |
5340 | -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb | |
5341 | -- and exp_ch6.adb. | |
5342 | ||
5343 | if Is_Entity_Name (Exp) | |
5344 | and then Nkind (Parent (Entity (Exp))) = | |
5345 | N_Object_Renaming_Declaration | |
5346 | then | |
5347 | declare | |
5348 | Old_Exp : constant Node_Id := Name (Parent (Entity (Exp))); | |
5349 | begin | |
5350 | if Nkind (Old_Exp) = N_Indexed_Component | |
5351 | and then Is_Bit_Packed_Array (Etype (Prefix (Old_Exp))) | |
5352 | then | |
5353 | Expand_Packed_Element_Reference (Old_Exp); | |
5354 | end if; | |
5355 | end; | |
5356 | end if; | |
5357 | ||
5358 | -- Put back the Do_Range_Check flag on the resulting (possibly | |
5359 | -- rewritten) expression. | |
5360 | ||
5361 | -- Note: it might be thought that a validity check is not required | |
5362 | -- when a range check is present, but that's not the case, because | |
5363 | -- the back end is allowed to assume for the range check that the | |
5364 | -- operand is within its declared range (an assumption that validity | |
5365 | -- checking is all about NOT assuming!) | |
5366 | ||
00c403ee | 5367 | -- Note: no need to worry about Possible_Local_Raise here, it will |
5368 | -- already have been called if original node has Do_Range_Check set. | |
5369 | ||
0577b0b1 | 5370 | Set_Do_Range_Check (Exp, DRC); |
5371 | end; | |
ee6ba406 | 5372 | end Insert_Valid_Check; |
5373 | ||
fa7497e8 | 5374 | ---------------------------------- |
5375 | -- Install_Null_Excluding_Check -- | |
5376 | ---------------------------------- | |
5377 | ||
5378 | procedure Install_Null_Excluding_Check (N : Node_Id) is | |
9f294c82 | 5379 | Loc : constant Source_Ptr := Sloc (Parent (N)); |
84d0d4a5 | 5380 | Typ : constant Entity_Id := Etype (N); |
5381 | ||
7b31b357 | 5382 | function Safe_To_Capture_In_Parameter_Value return Boolean; |
5383 | -- Determines if it is safe to capture Known_Non_Null status for an | |
5384 | -- the entity referenced by node N. The caller ensures that N is indeed | |
5385 | -- an entity name. It is safe to capture the non-null status for an IN | |
5386 | -- parameter when the reference occurs within a declaration that is sure | |
5387 | -- to be executed as part of the declarative region. | |
7870823d | 5388 | |
84d0d4a5 | 5389 | procedure Mark_Non_Null; |
7870823d | 5390 | -- After installation of check, if the node in question is an entity |
5391 | -- name, then mark this entity as non-null if possible. | |
5392 | ||
7b31b357 | 5393 | function Safe_To_Capture_In_Parameter_Value return Boolean is |
7870823d | 5394 | E : constant Entity_Id := Entity (N); |
5395 | S : constant Entity_Id := Current_Scope; | |
5396 | S_Par : Node_Id; | |
5397 | ||
5398 | begin | |
7b31b357 | 5399 | if Ekind (E) /= E_In_Parameter then |
5400 | return False; | |
5401 | end if; | |
7870823d | 5402 | |
5403 | -- Two initial context checks. We must be inside a subprogram body | |
5404 | -- with declarations and reference must not appear in nested scopes. | |
5405 | ||
7b31b357 | 5406 | if (Ekind (S) /= E_Function and then Ekind (S) /= E_Procedure) |
7870823d | 5407 | or else Scope (E) /= S |
5408 | then | |
5409 | return False; | |
5410 | end if; | |
5411 | ||
5412 | S_Par := Parent (Parent (S)); | |
5413 | ||
5414 | if Nkind (S_Par) /= N_Subprogram_Body | |
5415 | or else No (Declarations (S_Par)) | |
5416 | then | |
5417 | return False; | |
5418 | end if; | |
5419 | ||
5420 | declare | |
5421 | N_Decl : Node_Id; | |
5422 | P : Node_Id; | |
5423 | ||
5424 | begin | |
5425 | -- Retrieve the declaration node of N (if any). Note that N | |
5426 | -- may be a part of a complex initialization expression. | |
5427 | ||
5428 | P := Parent (N); | |
5429 | N_Decl := Empty; | |
5430 | while Present (P) loop | |
5431 | ||
7b31b357 | 5432 | -- If we have a short circuit form, and we are within the right |
5433 | -- hand expression, we return false, since the right hand side | |
5434 | -- is not guaranteed to be elaborated. | |
5435 | ||
5436 | if Nkind (P) in N_Short_Circuit | |
5437 | and then N = Right_Opnd (P) | |
5438 | then | |
5439 | return False; | |
5440 | end if; | |
5441 | ||
5442 | -- Similarly, if we are in a conditional expression and not | |
5443 | -- part of the condition, then we return False, since neither | |
5444 | -- the THEN or ELSE expressions will always be elaborated. | |
5445 | ||
5446 | if Nkind (P) = N_Conditional_Expression | |
5447 | and then N /= First (Expressions (P)) | |
5448 | then | |
5449 | return False; | |
e977c0cf | 5450 | end if; |
5451 | ||
6fb3c314 | 5452 | -- If we are in a case expression, and not part of the |
e977c0cf | 5453 | -- expression, then we return False, since a particular |
5454 | -- branch may not always be elaborated | |
5455 | ||
5456 | if Nkind (P) = N_Case_Expression | |
5457 | and then N /= Expression (P) | |
5458 | then | |
5459 | return False; | |
7b31b357 | 5460 | end if; |
5461 | ||
7870823d | 5462 | -- While traversing the parent chain, we find that N |
5463 | -- belongs to a statement, thus it may never appear in | |
5464 | -- a declarative region. | |
5465 | ||
5466 | if Nkind (P) in N_Statement_Other_Than_Procedure_Call | |
5467 | or else Nkind (P) = N_Procedure_Call_Statement | |
5468 | then | |
5469 | return False; | |
5470 | end if; | |
5471 | ||
7b31b357 | 5472 | -- If we are at a declaration, record it and exit |
5473 | ||
7870823d | 5474 | if Nkind (P) in N_Declaration |
5475 | and then Nkind (P) not in N_Subprogram_Specification | |
5476 | then | |
5477 | N_Decl := P; | |
5478 | exit; | |
5479 | end if; | |
5480 | ||
5481 | P := Parent (P); | |
5482 | end loop; | |
5483 | ||
5484 | if No (N_Decl) then | |
5485 | return False; | |
5486 | end if; | |
5487 | ||
5488 | return List_Containing (N_Decl) = Declarations (S_Par); | |
5489 | end; | |
7b31b357 | 5490 | end Safe_To_Capture_In_Parameter_Value; |
84d0d4a5 | 5491 | |
5492 | ------------------- | |
5493 | -- Mark_Non_Null -- | |
5494 | ------------------- | |
5495 | ||
5496 | procedure Mark_Non_Null is | |
5497 | begin | |
7870823d | 5498 | -- Only case of interest is if node N is an entity name |
5499 | ||
84d0d4a5 | 5500 | if Is_Entity_Name (N) then |
7870823d | 5501 | |
5502 | -- For sure, we want to clear an indication that this is known to | |
5503 | -- be null, since if we get past this check, it definitely is not! | |
5504 | ||
84d0d4a5 | 5505 | Set_Is_Known_Null (Entity (N), False); |
5506 | ||
7870823d | 5507 | -- We can mark the entity as known to be non-null if either it is |
5508 | -- safe to capture the value, or in the case of an IN parameter, | |
5509 | -- which is a constant, if the check we just installed is in the | |
5510 | -- declarative region of the subprogram body. In this latter case, | |
7b31b357 | 5511 | -- a check is decisive for the rest of the body if the expression |
5512 | -- is sure to be elaborated, since we know we have to elaborate | |
5513 | -- all declarations before executing the body. | |
5514 | ||
5515 | -- Couldn't this always be part of Safe_To_Capture_Value ??? | |
7870823d | 5516 | |
5517 | if Safe_To_Capture_Value (N, Entity (N)) | |
7b31b357 | 5518 | or else Safe_To_Capture_In_Parameter_Value |
7870823d | 5519 | then |
5520 | Set_Is_Known_Non_Null (Entity (N)); | |
84d0d4a5 | 5521 | end if; |
5522 | end if; | |
5523 | end Mark_Non_Null; | |
5524 | ||
5525 | -- Start of processing for Install_Null_Excluding_Check | |
fa7497e8 | 5526 | |
5527 | begin | |
84d0d4a5 | 5528 | pragma Assert (Is_Access_Type (Typ)); |
fa7497e8 | 5529 | |
84d0d4a5 | 5530 | -- No check inside a generic (why not???) |
fa7497e8 | 5531 | |
84d0d4a5 | 5532 | if Inside_A_Generic then |
fa7497e8 | 5533 | return; |
84d0d4a5 | 5534 | end if; |
5535 | ||
5536 | -- No check needed if known to be non-null | |
5537 | ||
5538 | if Known_Non_Null (N) then | |
05fcfafb | 5539 | return; |
84d0d4a5 | 5540 | end if; |
fa7497e8 | 5541 | |
84d0d4a5 | 5542 | -- If known to be null, here is where we generate a compile time check |
5543 | ||
5544 | if Known_Null (N) then | |
d16989f1 | 5545 | |
5546 | -- Avoid generating warning message inside init procs | |
5547 | ||
5548 | if not Inside_Init_Proc then | |
5549 | Apply_Compile_Time_Constraint_Error | |
5550 | (N, | |
5551 | "null value not allowed here?", | |
5552 | CE_Access_Check_Failed); | |
5553 | else | |
5554 | Insert_Action (N, | |
5555 | Make_Raise_Constraint_Error (Loc, | |
5556 | Reason => CE_Access_Check_Failed)); | |
5557 | end if; | |
5558 | ||
84d0d4a5 | 5559 | Mark_Non_Null; |
5560 | return; | |
5561 | end if; | |
5562 | ||
5563 | -- If entity is never assigned, for sure a warning is appropriate | |
5564 | ||
5565 | if Is_Entity_Name (N) then | |
5566 | Check_Unset_Reference (N); | |
fa7497e8 | 5567 | end if; |
84d0d4a5 | 5568 | |
5569 | -- No check needed if checks are suppressed on the range. Note that we | |
5570 | -- don't set Is_Known_Non_Null in this case (we could legitimately do | |
5571 | -- so, since the program is erroneous, but we don't like to casually | |
5572 | -- propagate such conclusions from erroneosity). | |
5573 | ||
5574 | if Access_Checks_Suppressed (Typ) then | |
5575 | return; | |
5576 | end if; | |
5577 | ||
2af58f67 | 5578 | -- No check needed for access to concurrent record types generated by |
5579 | -- the expander. This is not just an optimization (though it does indeed | |
5580 | -- remove junk checks). It also avoids generation of junk warnings. | |
5581 | ||
5582 | if Nkind (N) in N_Has_Chars | |
5583 | and then Chars (N) = Name_uObject | |
5584 | and then Is_Concurrent_Record_Type | |
5585 | (Directly_Designated_Type (Etype (N))) | |
5586 | then | |
5587 | return; | |
5588 | end if; | |
5589 | ||
84d0d4a5 | 5590 | -- Otherwise install access check |
5591 | ||
5592 | Insert_Action (N, | |
5593 | Make_Raise_Constraint_Error (Loc, | |
5594 | Condition => | |
5595 | Make_Op_Eq (Loc, | |
5596 | Left_Opnd => Duplicate_Subexpr_Move_Checks (N), | |
5597 | Right_Opnd => Make_Null (Loc)), | |
5598 | Reason => CE_Access_Check_Failed)); | |
5599 | ||
5600 | Mark_Non_Null; | |
fa7497e8 | 5601 | end Install_Null_Excluding_Check; |
5602 | ||
ee6ba406 | 5603 | -------------------------- |
5604 | -- Install_Static_Check -- | |
5605 | -------------------------- | |
5606 | ||
5607 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is | |
5608 | Stat : constant Boolean := Is_Static_Expression (R_Cno); | |
5609 | Typ : constant Entity_Id := Etype (R_Cno); | |
5610 | ||
5611 | begin | |
f15731c4 | 5612 | Rewrite (R_Cno, |
5613 | Make_Raise_Constraint_Error (Loc, | |
5614 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 5615 | Set_Analyzed (R_Cno); |
5616 | Set_Etype (R_Cno, Typ); | |
5617 | Set_Raises_Constraint_Error (R_Cno); | |
5618 | Set_Is_Static_Expression (R_Cno, Stat); | |
840ab274 | 5619 | |
5620 | -- Now deal with possible local raise handling | |
5621 | ||
5622 | Possible_Local_Raise (R_Cno, Standard_Constraint_Error); | |
ee6ba406 | 5623 | end Install_Static_Check; |
5624 | ||
9dfe12ae | 5625 | --------------------- |
5626 | -- Kill_All_Checks -- | |
5627 | --------------------- | |
5628 | ||
5629 | procedure Kill_All_Checks is | |
5630 | begin | |
5631 | if Debug_Flag_CC then | |
5632 | w ("Kill_All_Checks"); | |
5633 | end if; | |
5634 | ||
feff2f05 | 5635 | -- We reset the number of saved checks to zero, and also modify all |
5636 | -- stack entries for statement ranges to indicate that the number of | |
5637 | -- checks at each level is now zero. | |
9dfe12ae | 5638 | |
5639 | Num_Saved_Checks := 0; | |
5640 | ||
96da3284 | 5641 | -- Note: the Int'Min here avoids any possibility of J being out of |
5642 | -- range when called from e.g. Conditional_Statements_Begin. | |
5643 | ||
5644 | for J in 1 .. Int'Min (Saved_Checks_TOS, Saved_Checks_Stack'Last) loop | |
9dfe12ae | 5645 | Saved_Checks_Stack (J) := 0; |
5646 | end loop; | |
5647 | end Kill_All_Checks; | |
5648 | ||
5649 | ----------------- | |
5650 | -- Kill_Checks -- | |
5651 | ----------------- | |
5652 | ||
5653 | procedure Kill_Checks (V : Entity_Id) is | |
5654 | begin | |
5655 | if Debug_Flag_CC then | |
5656 | w ("Kill_Checks for entity", Int (V)); | |
5657 | end if; | |
5658 | ||
5659 | for J in 1 .. Num_Saved_Checks loop | |
5660 | if Saved_Checks (J).Entity = V then | |
5661 | if Debug_Flag_CC then | |
5662 | w (" Checks killed for saved check ", J); | |
5663 | end if; | |
5664 | ||
5665 | Saved_Checks (J).Killed := True; | |
5666 | end if; | |
5667 | end loop; | |
5668 | end Kill_Checks; | |
5669 | ||
ee6ba406 | 5670 | ------------------------------ |
5671 | -- Length_Checks_Suppressed -- | |
5672 | ------------------------------ | |
5673 | ||
5674 | function Length_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5675 | begin | |
9dfe12ae | 5676 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
5677 | return Is_Check_Suppressed (E, Length_Check); | |
5678 | else | |
5679 | return Scope_Suppress (Length_Check); | |
5680 | end if; | |
ee6ba406 | 5681 | end Length_Checks_Suppressed; |
5682 | ||
5683 | -------------------------------- | |
5684 | -- Overflow_Checks_Suppressed -- | |
5685 | -------------------------------- | |
5686 | ||
5687 | function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5688 | begin | |
9dfe12ae | 5689 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
5690 | return Is_Check_Suppressed (E, Overflow_Check); | |
5691 | else | |
5692 | return Scope_Suppress (Overflow_Check); | |
5693 | end if; | |
ee6ba406 | 5694 | end Overflow_Checks_Suppressed; |
fc75802a | 5695 | |
ee6ba406 | 5696 | ----------------------------- |
5697 | -- Range_Checks_Suppressed -- | |
5698 | ----------------------------- | |
5699 | ||
5700 | function Range_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5701 | begin | |
9dfe12ae | 5702 | if Present (E) then |
5703 | ||
5704 | -- Note: for now we always suppress range checks on Vax float types, | |
5705 | -- since Gigi does not know how to generate these checks. | |
5706 | ||
5707 | if Vax_Float (E) then | |
5708 | return True; | |
5709 | elsif Kill_Range_Checks (E) then | |
5710 | return True; | |
5711 | elsif Checks_May_Be_Suppressed (E) then | |
5712 | return Is_Check_Suppressed (E, Range_Check); | |
5713 | end if; | |
5714 | end if; | |
ee6ba406 | 5715 | |
9dfe12ae | 5716 | return Scope_Suppress (Range_Check); |
ee6ba406 | 5717 | end Range_Checks_Suppressed; |
5718 | ||
0577b0b1 | 5719 | ----------------------------------------- |
5720 | -- Range_Or_Validity_Checks_Suppressed -- | |
5721 | ----------------------------------------- | |
5722 | ||
5723 | -- Note: the coding would be simpler here if we simply made appropriate | |
5724 | -- calls to Range/Validity_Checks_Suppressed, but that would result in | |
5725 | -- duplicated checks which we prefer to avoid. | |
5726 | ||
5727 | function Range_Or_Validity_Checks_Suppressed | |
5728 | (Expr : Node_Id) return Boolean | |
5729 | is | |
5730 | begin | |
5731 | -- Immediate return if scope checks suppressed for either check | |
5732 | ||
5733 | if Scope_Suppress (Range_Check) or Scope_Suppress (Validity_Check) then | |
5734 | return True; | |
5735 | end if; | |
5736 | ||
5737 | -- If no expression, that's odd, decide that checks are suppressed, | |
5738 | -- since we don't want anyone trying to do checks in this case, which | |
5739 | -- is most likely the result of some other error. | |
5740 | ||
5741 | if No (Expr) then | |
5742 | return True; | |
5743 | end if; | |
5744 | ||
5745 | -- Expression is present, so perform suppress checks on type | |
5746 | ||
5747 | declare | |
5748 | Typ : constant Entity_Id := Etype (Expr); | |
5749 | begin | |
5750 | if Vax_Float (Typ) then | |
5751 | return True; | |
5752 | elsif Checks_May_Be_Suppressed (Typ) | |
5753 | and then (Is_Check_Suppressed (Typ, Range_Check) | |
5754 | or else | |
5755 | Is_Check_Suppressed (Typ, Validity_Check)) | |
5756 | then | |
5757 | return True; | |
5758 | end if; | |
5759 | end; | |
5760 | ||
5761 | -- If expression is an entity name, perform checks on this entity | |
5762 | ||
5763 | if Is_Entity_Name (Expr) then | |
5764 | declare | |
5765 | Ent : constant Entity_Id := Entity (Expr); | |
5766 | begin | |
5767 | if Checks_May_Be_Suppressed (Ent) then | |
5768 | return Is_Check_Suppressed (Ent, Range_Check) | |
5769 | or else Is_Check_Suppressed (Ent, Validity_Check); | |
5770 | end if; | |
5771 | end; | |
5772 | end if; | |
5773 | ||
5774 | -- If we fall through, no checks suppressed | |
5775 | ||
5776 | return False; | |
5777 | end Range_Or_Validity_Checks_Suppressed; | |
5778 | ||
226494a3 | 5779 | ------------------- |
5780 | -- Remove_Checks -- | |
5781 | ------------------- | |
5782 | ||
5783 | procedure Remove_Checks (Expr : Node_Id) is | |
226494a3 | 5784 | function Process (N : Node_Id) return Traverse_Result; |
5785 | -- Process a single node during the traversal | |
5786 | ||
8f6e4fd5 | 5787 | procedure Traverse is new Traverse_Proc (Process); |
5788 | -- The traversal procedure itself | |
226494a3 | 5789 | |
5790 | ------------- | |
5791 | -- Process -- | |
5792 | ------------- | |
5793 | ||
5794 | function Process (N : Node_Id) return Traverse_Result is | |
5795 | begin | |
5796 | if Nkind (N) not in N_Subexpr then | |
5797 | return Skip; | |
5798 | end if; | |
5799 | ||
5800 | Set_Do_Range_Check (N, False); | |
5801 | ||
5802 | case Nkind (N) is | |
5803 | when N_And_Then => | |
8f6e4fd5 | 5804 | Traverse (Left_Opnd (N)); |
226494a3 | 5805 | return Skip; |
5806 | ||
5807 | when N_Attribute_Reference => | |
226494a3 | 5808 | Set_Do_Overflow_Check (N, False); |
5809 | ||
226494a3 | 5810 | when N_Function_Call => |
5811 | Set_Do_Tag_Check (N, False); | |
5812 | ||
226494a3 | 5813 | when N_Op => |
5814 | Set_Do_Overflow_Check (N, False); | |
5815 | ||
5816 | case Nkind (N) is | |
5817 | when N_Op_Divide => | |
5818 | Set_Do_Division_Check (N, False); | |
5819 | ||
5820 | when N_Op_And => | |
5821 | Set_Do_Length_Check (N, False); | |
5822 | ||
5823 | when N_Op_Mod => | |
5824 | Set_Do_Division_Check (N, False); | |
5825 | ||
5826 | when N_Op_Or => | |
5827 | Set_Do_Length_Check (N, False); | |
5828 | ||
5829 | when N_Op_Rem => | |
5830 | Set_Do_Division_Check (N, False); | |
5831 | ||
5832 | when N_Op_Xor => | |
5833 | Set_Do_Length_Check (N, False); | |
5834 | ||
5835 | when others => | |
5836 | null; | |
5837 | end case; | |
5838 | ||
5839 | when N_Or_Else => | |
8f6e4fd5 | 5840 | Traverse (Left_Opnd (N)); |
226494a3 | 5841 | return Skip; |
5842 | ||
5843 | when N_Selected_Component => | |
226494a3 | 5844 | Set_Do_Discriminant_Check (N, False); |
5845 | ||
226494a3 | 5846 | when N_Type_Conversion => |
9dfe12ae | 5847 | Set_Do_Length_Check (N, False); |
5848 | Set_Do_Tag_Check (N, False); | |
226494a3 | 5849 | Set_Do_Overflow_Check (N, False); |
226494a3 | 5850 | |
5851 | when others => | |
5852 | null; | |
5853 | end case; | |
5854 | ||
5855 | return OK; | |
5856 | end Process; | |
5857 | ||
5858 | -- Start of processing for Remove_Checks | |
5859 | ||
5860 | begin | |
8f6e4fd5 | 5861 | Traverse (Expr); |
226494a3 | 5862 | end Remove_Checks; |
5863 | ||
ee6ba406 | 5864 | ---------------------------- |
5865 | -- Selected_Length_Checks -- | |
5866 | ---------------------------- | |
5867 | ||
5868 | function Selected_Length_Checks | |
5869 | (Ck_Node : Node_Id; | |
5870 | Target_Typ : Entity_Id; | |
5871 | Source_Typ : Entity_Id; | |
314a23b6 | 5872 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 5873 | is |
5874 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
5875 | S_Typ : Entity_Id; | |
5876 | T_Typ : Entity_Id; | |
5877 | Expr_Actual : Node_Id; | |
5878 | Exptyp : Entity_Id; | |
5879 | Cond : Node_Id := Empty; | |
5880 | Do_Access : Boolean := False; | |
5881 | Wnode : Node_Id := Warn_Node; | |
5882 | Ret_Result : Check_Result := (Empty, Empty); | |
5883 | Num_Checks : Natural := 0; | |
5884 | ||
5885 | procedure Add_Check (N : Node_Id); | |
5886 | -- Adds the action given to Ret_Result if N is non-Empty | |
5887 | ||
5888 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id; | |
5889 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id; | |
314a23b6 | 5890 | -- Comments required ??? |
ee6ba406 | 5891 | |
5892 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean; | |
5893 | -- True for equal literals and for nodes that denote the same constant | |
5f260d20 | 5894 | -- entity, even if its value is not a static constant. This includes the |
9dfe12ae | 5895 | -- case of a discriminal reference within an init proc. Removes some |
5f260d20 | 5896 | -- obviously superfluous checks. |
ee6ba406 | 5897 | |
5898 | function Length_E_Cond | |
5899 | (Exptyp : Entity_Id; | |
5900 | Typ : Entity_Id; | |
314a23b6 | 5901 | Indx : Nat) return Node_Id; |
ee6ba406 | 5902 | -- Returns expression to compute: |
5903 | -- Typ'Length /= Exptyp'Length | |
5904 | ||
5905 | function Length_N_Cond | |
5906 | (Expr : Node_Id; | |
5907 | Typ : Entity_Id; | |
314a23b6 | 5908 | Indx : Nat) return Node_Id; |
ee6ba406 | 5909 | -- Returns expression to compute: |
5910 | -- Typ'Length /= Expr'Length | |
5911 | ||
5912 | --------------- | |
5913 | -- Add_Check -- | |
5914 | --------------- | |
5915 | ||
5916 | procedure Add_Check (N : Node_Id) is | |
5917 | begin | |
5918 | if Present (N) then | |
5919 | ||
5920 | -- For now, ignore attempt to place more than 2 checks ??? | |
5921 | ||
5922 | if Num_Checks = 2 then | |
5923 | return; | |
5924 | end if; | |
5925 | ||
5926 | pragma Assert (Num_Checks <= 1); | |
5927 | Num_Checks := Num_Checks + 1; | |
5928 | Ret_Result (Num_Checks) := N; | |
5929 | end if; | |
5930 | end Add_Check; | |
5931 | ||
5932 | ------------------ | |
5933 | -- Get_E_Length -- | |
5934 | ------------------ | |
5935 | ||
5936 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is | |
00c403ee | 5937 | SE : constant Entity_Id := Scope (E); |
ee6ba406 | 5938 | N : Node_Id; |
5939 | E1 : Entity_Id := E; | |
ee6ba406 | 5940 | |
5941 | begin | |
5942 | if Ekind (Scope (E)) = E_Record_Type | |
5943 | and then Has_Discriminants (Scope (E)) | |
5944 | then | |
5945 | N := Build_Discriminal_Subtype_Of_Component (E); | |
5946 | ||
5947 | if Present (N) then | |
5948 | Insert_Action (Ck_Node, N); | |
5949 | E1 := Defining_Identifier (N); | |
5950 | end if; | |
5951 | end if; | |
5952 | ||
5953 | if Ekind (E1) = E_String_Literal_Subtype then | |
5954 | return | |
5955 | Make_Integer_Literal (Loc, | |
5956 | Intval => String_Literal_Length (E1)); | |
5957 | ||
00c403ee | 5958 | elsif SE /= Standard_Standard |
5959 | and then Ekind (Scope (SE)) = E_Protected_Type | |
5960 | and then Has_Discriminants (Scope (SE)) | |
5961 | and then Has_Completion (Scope (SE)) | |
ee6ba406 | 5962 | and then not Inside_Init_Proc |
5963 | then | |
ee6ba406 | 5964 | -- If the type whose length is needed is a private component |
5965 | -- constrained by a discriminant, we must expand the 'Length | |
5966 | -- attribute into an explicit computation, using the discriminal | |
5967 | -- of the current protected operation. This is because the actual | |
5968 | -- type of the prival is constructed after the protected opera- | |
5969 | -- tion has been fully expanded. | |
5970 | ||
5971 | declare | |
5972 | Indx_Type : Node_Id; | |
5973 | Lo : Node_Id; | |
5974 | Hi : Node_Id; | |
5975 | Do_Expand : Boolean := False; | |
5976 | ||
5977 | begin | |
5978 | Indx_Type := First_Index (E); | |
5979 | ||
5980 | for J in 1 .. Indx - 1 loop | |
5981 | Next_Index (Indx_Type); | |
5982 | end loop; | |
5983 | ||
2af58f67 | 5984 | Get_Index_Bounds (Indx_Type, Lo, Hi); |
ee6ba406 | 5985 | |
5986 | if Nkind (Lo) = N_Identifier | |
5987 | and then Ekind (Entity (Lo)) = E_In_Parameter | |
5988 | then | |
5989 | Lo := Get_Discriminal (E, Lo); | |
5990 | Do_Expand := True; | |
5991 | end if; | |
5992 | ||
5993 | if Nkind (Hi) = N_Identifier | |
5994 | and then Ekind (Entity (Hi)) = E_In_Parameter | |
5995 | then | |
5996 | Hi := Get_Discriminal (E, Hi); | |
5997 | Do_Expand := True; | |
5998 | end if; | |
5999 | ||
6000 | if Do_Expand then | |
6001 | if not Is_Entity_Name (Lo) then | |
9dfe12ae | 6002 | Lo := Duplicate_Subexpr_No_Checks (Lo); |
ee6ba406 | 6003 | end if; |
6004 | ||
6005 | if not Is_Entity_Name (Hi) then | |
9dfe12ae | 6006 | Lo := Duplicate_Subexpr_No_Checks (Hi); |
ee6ba406 | 6007 | end if; |
6008 | ||
6009 | N := | |
6010 | Make_Op_Add (Loc, | |
6011 | Left_Opnd => | |
6012 | Make_Op_Subtract (Loc, | |
6013 | Left_Opnd => Hi, | |
6014 | Right_Opnd => Lo), | |
6015 | ||
6016 | Right_Opnd => Make_Integer_Literal (Loc, 1)); | |
6017 | return N; | |
6018 | ||
6019 | else | |
6020 | N := | |
6021 | Make_Attribute_Reference (Loc, | |
6022 | Attribute_Name => Name_Length, | |
6023 | Prefix => | |
6024 | New_Occurrence_Of (E1, Loc)); | |
6025 | ||
6026 | if Indx > 1 then | |
6027 | Set_Expressions (N, New_List ( | |
6028 | Make_Integer_Literal (Loc, Indx))); | |
6029 | end if; | |
6030 | ||
6031 | return N; | |
6032 | end if; | |
6033 | end; | |
6034 | ||
6035 | else | |
6036 | N := | |
6037 | Make_Attribute_Reference (Loc, | |
6038 | Attribute_Name => Name_Length, | |
6039 | Prefix => | |
6040 | New_Occurrence_Of (E1, Loc)); | |
6041 | ||
6042 | if Indx > 1 then | |
6043 | Set_Expressions (N, New_List ( | |
6044 | Make_Integer_Literal (Loc, Indx))); | |
6045 | end if; | |
6046 | ||
6047 | return N; | |
ee6ba406 | 6048 | end if; |
6049 | end Get_E_Length; | |
6050 | ||
6051 | ------------------ | |
6052 | -- Get_N_Length -- | |
6053 | ------------------ | |
6054 | ||
6055 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is | |
6056 | begin | |
6057 | return | |
6058 | Make_Attribute_Reference (Loc, | |
6059 | Attribute_Name => Name_Length, | |
6060 | Prefix => | |
9dfe12ae | 6061 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 6062 | Expressions => New_List ( |
6063 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 6064 | end Get_N_Length; |
6065 | ||
6066 | ------------------- | |
6067 | -- Length_E_Cond -- | |
6068 | ------------------- | |
6069 | ||
6070 | function Length_E_Cond | |
6071 | (Exptyp : Entity_Id; | |
6072 | Typ : Entity_Id; | |
314a23b6 | 6073 | Indx : Nat) return Node_Id |
ee6ba406 | 6074 | is |
6075 | begin | |
6076 | return | |
6077 | Make_Op_Ne (Loc, | |
6078 | Left_Opnd => Get_E_Length (Typ, Indx), | |
6079 | Right_Opnd => Get_E_Length (Exptyp, Indx)); | |
ee6ba406 | 6080 | end Length_E_Cond; |
6081 | ||
6082 | ------------------- | |
6083 | -- Length_N_Cond -- | |
6084 | ------------------- | |
6085 | ||
6086 | function Length_N_Cond | |
6087 | (Expr : Node_Id; | |
6088 | Typ : Entity_Id; | |
314a23b6 | 6089 | Indx : Nat) return Node_Id |
ee6ba406 | 6090 | is |
6091 | begin | |
6092 | return | |
6093 | Make_Op_Ne (Loc, | |
6094 | Left_Opnd => Get_E_Length (Typ, Indx), | |
6095 | Right_Opnd => Get_N_Length (Expr, Indx)); | |
ee6ba406 | 6096 | end Length_N_Cond; |
6097 | ||
feff2f05 | 6098 | ----------------- |
6099 | -- Same_Bounds -- | |
6100 | ----------------- | |
6101 | ||
ee6ba406 | 6102 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is |
6103 | begin | |
6104 | return | |
6105 | (Nkind (L) = N_Integer_Literal | |
6106 | and then Nkind (R) = N_Integer_Literal | |
6107 | and then Intval (L) = Intval (R)) | |
6108 | ||
6109 | or else | |
6110 | (Is_Entity_Name (L) | |
6111 | and then Ekind (Entity (L)) = E_Constant | |
6112 | and then ((Is_Entity_Name (R) | |
6113 | and then Entity (L) = Entity (R)) | |
6114 | or else | |
6115 | (Nkind (R) = N_Type_Conversion | |
6116 | and then Is_Entity_Name (Expression (R)) | |
6117 | and then Entity (L) = Entity (Expression (R))))) | |
6118 | ||
6119 | or else | |
6120 | (Is_Entity_Name (R) | |
6121 | and then Ekind (Entity (R)) = E_Constant | |
6122 | and then Nkind (L) = N_Type_Conversion | |
6123 | and then Is_Entity_Name (Expression (L)) | |
5f260d20 | 6124 | and then Entity (R) = Entity (Expression (L))) |
6125 | ||
6126 | or else | |
6127 | (Is_Entity_Name (L) | |
6128 | and then Is_Entity_Name (R) | |
6129 | and then Entity (L) = Entity (R) | |
6130 | and then Ekind (Entity (L)) = E_In_Parameter | |
6131 | and then Inside_Init_Proc); | |
ee6ba406 | 6132 | end Same_Bounds; |
6133 | ||
6134 | -- Start of processing for Selected_Length_Checks | |
6135 | ||
6136 | begin | |
6137 | if not Expander_Active then | |
6138 | return Ret_Result; | |
6139 | end if; | |
6140 | ||
6141 | if Target_Typ = Any_Type | |
6142 | or else Target_Typ = Any_Composite | |
6143 | or else Raises_Constraint_Error (Ck_Node) | |
6144 | then | |
6145 | return Ret_Result; | |
6146 | end if; | |
6147 | ||
6148 | if No (Wnode) then | |
6149 | Wnode := Ck_Node; | |
6150 | end if; | |
6151 | ||
6152 | T_Typ := Target_Typ; | |
6153 | ||
6154 | if No (Source_Typ) then | |
6155 | S_Typ := Etype (Ck_Node); | |
6156 | else | |
6157 | S_Typ := Source_Typ; | |
6158 | end if; | |
6159 | ||
6160 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
6161 | return Ret_Result; | |
6162 | end if; | |
6163 | ||
6164 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
6165 | S_Typ := Designated_Type (S_Typ); | |
6166 | T_Typ := Designated_Type (T_Typ); | |
6167 | Do_Access := True; | |
6168 | ||
2af58f67 | 6169 | -- A simple optimization for the null case |
ee6ba406 | 6170 | |
2af58f67 | 6171 | if Known_Null (Ck_Node) then |
ee6ba406 | 6172 | return Ret_Result; |
6173 | end if; | |
6174 | end if; | |
6175 | ||
6176 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
6177 | if Is_Constrained (T_Typ) then | |
6178 | ||
6179 | -- The checking code to be generated will freeze the | |
6180 | -- corresponding array type. However, we must freeze the | |
6181 | -- type now, so that the freeze node does not appear within | |
6fb3c314 | 6182 | -- the generated conditional expression, but ahead of it. |
ee6ba406 | 6183 | |
6184 | Freeze_Before (Ck_Node, T_Typ); | |
6185 | ||
6186 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
84d0d4a5 | 6187 | Exptyp := Get_Actual_Subtype (Ck_Node); |
ee6ba406 | 6188 | |
6189 | if Is_Access_Type (Exptyp) then | |
6190 | Exptyp := Designated_Type (Exptyp); | |
6191 | end if; | |
6192 | ||
6193 | -- String_Literal case. This needs to be handled specially be- | |
6194 | -- cause no index types are available for string literals. The | |
6195 | -- condition is simply: | |
6196 | ||
6197 | -- T_Typ'Length = string-literal-length | |
6198 | ||
9dfe12ae | 6199 | if Nkind (Expr_Actual) = N_String_Literal |
6200 | and then Ekind (Etype (Expr_Actual)) = E_String_Literal_Subtype | |
6201 | then | |
ee6ba406 | 6202 | Cond := |
6203 | Make_Op_Ne (Loc, | |
6204 | Left_Opnd => Get_E_Length (T_Typ, 1), | |
6205 | Right_Opnd => | |
6206 | Make_Integer_Literal (Loc, | |
6207 | Intval => | |
6208 | String_Literal_Length (Etype (Expr_Actual)))); | |
6209 | ||
6210 | -- General array case. Here we have a usable actual subtype for | |
6211 | -- the expression, and the condition is built from the two types | |
6212 | -- (Do_Length): | |
6213 | ||
6214 | -- T_Typ'Length /= Exptyp'Length or else | |
6215 | -- T_Typ'Length (2) /= Exptyp'Length (2) or else | |
6216 | -- T_Typ'Length (3) /= Exptyp'Length (3) or else | |
6217 | -- ... | |
6218 | ||
6219 | elsif Is_Constrained (Exptyp) then | |
6220 | declare | |
9dfe12ae | 6221 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
6222 | ||
6223 | L_Index : Node_Id; | |
6224 | R_Index : Node_Id; | |
6225 | L_Low : Node_Id; | |
6226 | L_High : Node_Id; | |
6227 | R_Low : Node_Id; | |
6228 | R_High : Node_Id; | |
ee6ba406 | 6229 | L_Length : Uint; |
6230 | R_Length : Uint; | |
9dfe12ae | 6231 | Ref_Node : Node_Id; |
ee6ba406 | 6232 | |
6233 | begin | |
feff2f05 | 6234 | -- At the library level, we need to ensure that the type of |
6235 | -- the object is elaborated before the check itself is | |
6236 | -- emitted. This is only done if the object is in the | |
6237 | -- current compilation unit, otherwise the type is frozen | |
6238 | -- and elaborated in its unit. | |
9dfe12ae | 6239 | |
6240 | if Is_Itype (Exptyp) | |
6241 | and then | |
6242 | Ekind (Cunit_Entity (Current_Sem_Unit)) = E_Package | |
6243 | and then | |
6244 | not In_Package_Body (Cunit_Entity (Current_Sem_Unit)) | |
d66aa9f6 | 6245 | and then In_Open_Scopes (Scope (Exptyp)) |
9dfe12ae | 6246 | then |
6247 | Ref_Node := Make_Itype_Reference (Sloc (Ck_Node)); | |
6248 | Set_Itype (Ref_Node, Exptyp); | |
6249 | Insert_Action (Ck_Node, Ref_Node); | |
6250 | end if; | |
6251 | ||
ee6ba406 | 6252 | L_Index := First_Index (T_Typ); |
6253 | R_Index := First_Index (Exptyp); | |
6254 | ||
6255 | for Indx in 1 .. Ndims loop | |
6256 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 6257 | or else |
6258 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 6259 | then |
6260 | Get_Index_Bounds (L_Index, L_Low, L_High); | |
6261 | Get_Index_Bounds (R_Index, R_Low, R_High); | |
6262 | ||
6263 | -- Deal with compile time length check. Note that we | |
6264 | -- skip this in the access case, because the access | |
6265 | -- value may be null, so we cannot know statically. | |
6266 | ||
6267 | if not Do_Access | |
6268 | and then Compile_Time_Known_Value (L_Low) | |
6269 | and then Compile_Time_Known_Value (L_High) | |
6270 | and then Compile_Time_Known_Value (R_Low) | |
6271 | and then Compile_Time_Known_Value (R_High) | |
6272 | then | |
6273 | if Expr_Value (L_High) >= Expr_Value (L_Low) then | |
6274 | L_Length := Expr_Value (L_High) - | |
6275 | Expr_Value (L_Low) + 1; | |
6276 | else | |
6277 | L_Length := UI_From_Int (0); | |
6278 | end if; | |
6279 | ||
6280 | if Expr_Value (R_High) >= Expr_Value (R_Low) then | |
6281 | R_Length := Expr_Value (R_High) - | |
6282 | Expr_Value (R_Low) + 1; | |
6283 | else | |
6284 | R_Length := UI_From_Int (0); | |
6285 | end if; | |
6286 | ||
6287 | if L_Length > R_Length then | |
6288 | Add_Check | |
6289 | (Compile_Time_Constraint_Error | |
6290 | (Wnode, "too few elements for}?", T_Typ)); | |
6291 | ||
6292 | elsif L_Length < R_Length then | |
6293 | Add_Check | |
6294 | (Compile_Time_Constraint_Error | |
6295 | (Wnode, "too many elements for}?", T_Typ)); | |
6296 | end if; | |
6297 | ||
6298 | -- The comparison for an individual index subtype | |
6299 | -- is omitted if the corresponding index subtypes | |
6300 | -- statically match, since the result is known to | |
6301 | -- be true. Note that this test is worth while even | |
6302 | -- though we do static evaluation, because non-static | |
6303 | -- subtypes can statically match. | |
6304 | ||
6305 | elsif not | |
6306 | Subtypes_Statically_Match | |
6307 | (Etype (L_Index), Etype (R_Index)) | |
6308 | ||
6309 | and then not | |
6310 | (Same_Bounds (L_Low, R_Low) | |
6311 | and then Same_Bounds (L_High, R_High)) | |
6312 | then | |
6313 | Evolve_Or_Else | |
6314 | (Cond, Length_E_Cond (Exptyp, T_Typ, Indx)); | |
6315 | end if; | |
6316 | ||
6317 | Next (L_Index); | |
6318 | Next (R_Index); | |
6319 | end if; | |
6320 | end loop; | |
6321 | end; | |
6322 | ||
6323 | -- Handle cases where we do not get a usable actual subtype that | |
6324 | -- is constrained. This happens for example in the function call | |
6325 | -- and explicit dereference cases. In these cases, we have to get | |
6326 | -- the length or range from the expression itself, making sure we | |
6327 | -- do not evaluate it more than once. | |
6328 | ||
6329 | -- Here Ck_Node is the original expression, or more properly the | |
feff2f05 | 6330 | -- result of applying Duplicate_Expr to the original tree, forcing |
6331 | -- the result to be a name. | |
ee6ba406 | 6332 | |
6333 | else | |
6334 | declare | |
9dfe12ae | 6335 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 6336 | |
6337 | begin | |
6338 | -- Build the condition for the explicit dereference case | |
6339 | ||
6340 | for Indx in 1 .. Ndims loop | |
6341 | Evolve_Or_Else | |
6342 | (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx)); | |
6343 | end loop; | |
6344 | end; | |
6345 | end if; | |
6346 | end if; | |
6347 | end if; | |
6348 | ||
6349 | -- Construct the test and insert into the tree | |
6350 | ||
6351 | if Present (Cond) then | |
6352 | if Do_Access then | |
6353 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
6354 | end if; | |
6355 | ||
f15731c4 | 6356 | Add_Check |
6357 | (Make_Raise_Constraint_Error (Loc, | |
6358 | Condition => Cond, | |
6359 | Reason => CE_Length_Check_Failed)); | |
ee6ba406 | 6360 | end if; |
6361 | ||
6362 | return Ret_Result; | |
ee6ba406 | 6363 | end Selected_Length_Checks; |
6364 | ||
6365 | --------------------------- | |
6366 | -- Selected_Range_Checks -- | |
6367 | --------------------------- | |
6368 | ||
6369 | function Selected_Range_Checks | |
6370 | (Ck_Node : Node_Id; | |
6371 | Target_Typ : Entity_Id; | |
6372 | Source_Typ : Entity_Id; | |
314a23b6 | 6373 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 6374 | is |
6375 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
6376 | S_Typ : Entity_Id; | |
6377 | T_Typ : Entity_Id; | |
6378 | Expr_Actual : Node_Id; | |
6379 | Exptyp : Entity_Id; | |
6380 | Cond : Node_Id := Empty; | |
6381 | Do_Access : Boolean := False; | |
6382 | Wnode : Node_Id := Warn_Node; | |
6383 | Ret_Result : Check_Result := (Empty, Empty); | |
6384 | Num_Checks : Integer := 0; | |
6385 | ||
6386 | procedure Add_Check (N : Node_Id); | |
6387 | -- Adds the action given to Ret_Result if N is non-Empty | |
6388 | ||
6389 | function Discrete_Range_Cond | |
6390 | (Expr : Node_Id; | |
314a23b6 | 6391 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 6392 | -- Returns expression to compute: |
6393 | -- Low_Bound (Expr) < Typ'First | |
6394 | -- or else | |
6395 | -- High_Bound (Expr) > Typ'Last | |
6396 | ||
6397 | function Discrete_Expr_Cond | |
6398 | (Expr : Node_Id; | |
314a23b6 | 6399 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 6400 | -- Returns expression to compute: |
6401 | -- Expr < Typ'First | |
6402 | -- or else | |
6403 | -- Expr > Typ'Last | |
6404 | ||
6405 | function Get_E_First_Or_Last | |
3cb12758 | 6406 | (Loc : Source_Ptr; |
6407 | E : Entity_Id; | |
ee6ba406 | 6408 | Indx : Nat; |
314a23b6 | 6409 | Nam : Name_Id) return Node_Id; |
79212397 | 6410 | -- Returns an attribute reference |
ee6ba406 | 6411 | -- E'First or E'Last |
79212397 | 6412 | -- with a source location of Loc. |
f73ee678 | 6413 | -- |
79212397 | 6414 | -- Nam is Name_First or Name_Last, according to which attribute is |
6415 | -- desired. If Indx is non-zero, it is passed as a literal in the | |
6416 | -- Expressions of the attribute reference (identifying the desired | |
6417 | -- array dimension). | |
ee6ba406 | 6418 | |
6419 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id; | |
6420 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id; | |
6421 | -- Returns expression to compute: | |
9dfe12ae | 6422 | -- N'First or N'Last using Duplicate_Subexpr_No_Checks |
ee6ba406 | 6423 | |
6424 | function Range_E_Cond | |
6425 | (Exptyp : Entity_Id; | |
6426 | Typ : Entity_Id; | |
6427 | Indx : Nat) | |
6428 | return Node_Id; | |
6429 | -- Returns expression to compute: | |
6430 | -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last | |
6431 | ||
6432 | function Range_Equal_E_Cond | |
6433 | (Exptyp : Entity_Id; | |
6434 | Typ : Entity_Id; | |
314a23b6 | 6435 | Indx : Nat) return Node_Id; |
ee6ba406 | 6436 | -- Returns expression to compute: |
6437 | -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last | |
6438 | ||
6439 | function Range_N_Cond | |
6440 | (Expr : Node_Id; | |
6441 | Typ : Entity_Id; | |
314a23b6 | 6442 | Indx : Nat) return Node_Id; |
ee6ba406 | 6443 | -- Return expression to compute: |
6444 | -- Expr'First < Typ'First or else Expr'Last > Typ'Last | |
6445 | ||
6446 | --------------- | |
6447 | -- Add_Check -- | |
6448 | --------------- | |
6449 | ||
6450 | procedure Add_Check (N : Node_Id) is | |
6451 | begin | |
6452 | if Present (N) then | |
6453 | ||
6454 | -- For now, ignore attempt to place more than 2 checks ??? | |
6455 | ||
6456 | if Num_Checks = 2 then | |
6457 | return; | |
6458 | end if; | |
6459 | ||
6460 | pragma Assert (Num_Checks <= 1); | |
6461 | Num_Checks := Num_Checks + 1; | |
6462 | Ret_Result (Num_Checks) := N; | |
6463 | end if; | |
6464 | end Add_Check; | |
6465 | ||
6466 | ------------------------- | |
6467 | -- Discrete_Expr_Cond -- | |
6468 | ------------------------- | |
6469 | ||
6470 | function Discrete_Expr_Cond | |
6471 | (Expr : Node_Id; | |
314a23b6 | 6472 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 6473 | is |
6474 | begin | |
6475 | return | |
6476 | Make_Or_Else (Loc, | |
6477 | Left_Opnd => | |
6478 | Make_Op_Lt (Loc, | |
6479 | Left_Opnd => | |
9dfe12ae | 6480 | Convert_To (Base_Type (Typ), |
6481 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 6482 | Right_Opnd => |
6483 | Convert_To (Base_Type (Typ), | |
3cb12758 | 6484 | Get_E_First_Or_Last (Loc, Typ, 0, Name_First))), |
ee6ba406 | 6485 | |
6486 | Right_Opnd => | |
6487 | Make_Op_Gt (Loc, | |
6488 | Left_Opnd => | |
9dfe12ae | 6489 | Convert_To (Base_Type (Typ), |
6490 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 6491 | Right_Opnd => |
6492 | Convert_To | |
6493 | (Base_Type (Typ), | |
3cb12758 | 6494 | Get_E_First_Or_Last (Loc, Typ, 0, Name_Last)))); |
ee6ba406 | 6495 | end Discrete_Expr_Cond; |
6496 | ||
6497 | ------------------------- | |
6498 | -- Discrete_Range_Cond -- | |
6499 | ------------------------- | |
6500 | ||
6501 | function Discrete_Range_Cond | |
6502 | (Expr : Node_Id; | |
314a23b6 | 6503 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 6504 | is |
6505 | LB : Node_Id := Low_Bound (Expr); | |
6506 | HB : Node_Id := High_Bound (Expr); | |
6507 | ||
6508 | Left_Opnd : Node_Id; | |
6509 | Right_Opnd : Node_Id; | |
6510 | ||
6511 | begin | |
6512 | if Nkind (LB) = N_Identifier | |
feff2f05 | 6513 | and then Ekind (Entity (LB)) = E_Discriminant |
6514 | then | |
ee6ba406 | 6515 | LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc); |
6516 | end if; | |
6517 | ||
6518 | if Nkind (HB) = N_Identifier | |
feff2f05 | 6519 | and then Ekind (Entity (HB)) = E_Discriminant |
6520 | then | |
ee6ba406 | 6521 | HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc); |
6522 | end if; | |
6523 | ||
6524 | Left_Opnd := | |
6525 | Make_Op_Lt (Loc, | |
6526 | Left_Opnd => | |
6527 | Convert_To | |
9dfe12ae | 6528 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (LB)), |
ee6ba406 | 6529 | |
6530 | Right_Opnd => | |
6531 | Convert_To | |
3cb12758 | 6532 | (Base_Type (Typ), |
6533 | Get_E_First_Or_Last (Loc, Typ, 0, Name_First))); | |
ee6ba406 | 6534 | |
6535 | if Base_Type (Typ) = Typ then | |
6536 | return Left_Opnd; | |
6537 | ||
6538 | elsif Compile_Time_Known_Value (High_Bound (Scalar_Range (Typ))) | |
6539 | and then | |
6540 | Compile_Time_Known_Value (High_Bound (Scalar_Range | |
6541 | (Base_Type (Typ)))) | |
6542 | then | |
6543 | if Is_Floating_Point_Type (Typ) then | |
6544 | if Expr_Value_R (High_Bound (Scalar_Range (Typ))) = | |
6545 | Expr_Value_R (High_Bound (Scalar_Range (Base_Type (Typ)))) | |
6546 | then | |
6547 | return Left_Opnd; | |
6548 | end if; | |
6549 | ||
6550 | else | |
6551 | if Expr_Value (High_Bound (Scalar_Range (Typ))) = | |
6552 | Expr_Value (High_Bound (Scalar_Range (Base_Type (Typ)))) | |
6553 | then | |
6554 | return Left_Opnd; | |
6555 | end if; | |
6556 | end if; | |
6557 | end if; | |
6558 | ||
6559 | Right_Opnd := | |
6560 | Make_Op_Gt (Loc, | |
6561 | Left_Opnd => | |
6562 | Convert_To | |
9dfe12ae | 6563 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (HB)), |
ee6ba406 | 6564 | |
6565 | Right_Opnd => | |
6566 | Convert_To | |
6567 | (Base_Type (Typ), | |
3cb12758 | 6568 | Get_E_First_Or_Last (Loc, Typ, 0, Name_Last))); |
ee6ba406 | 6569 | |
6570 | return Make_Or_Else (Loc, Left_Opnd, Right_Opnd); | |
6571 | end Discrete_Range_Cond; | |
6572 | ||
6573 | ------------------------- | |
6574 | -- Get_E_First_Or_Last -- | |
6575 | ------------------------- | |
6576 | ||
6577 | function Get_E_First_Or_Last | |
3cb12758 | 6578 | (Loc : Source_Ptr; |
6579 | E : Entity_Id; | |
ee6ba406 | 6580 | Indx : Nat; |
314a23b6 | 6581 | Nam : Name_Id) return Node_Id |
ee6ba406 | 6582 | is |
3cb12758 | 6583 | Exprs : List_Id; |
ee6ba406 | 6584 | begin |
3cb12758 | 6585 | if Indx > 0 then |
6586 | Exprs := New_List (Make_Integer_Literal (Loc, UI_From_Int (Indx))); | |
ee6ba406 | 6587 | else |
3cb12758 | 6588 | Exprs := No_List; |
ee6ba406 | 6589 | end if; |
6590 | ||
3cb12758 | 6591 | return Make_Attribute_Reference (Loc, |
6592 | Prefix => New_Occurrence_Of (E, Loc), | |
6593 | Attribute_Name => Nam, | |
6594 | Expressions => Exprs); | |
ee6ba406 | 6595 | end Get_E_First_Or_Last; |
6596 | ||
6597 | ----------------- | |
6598 | -- Get_N_First -- | |
6599 | ----------------- | |
6600 | ||
6601 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is | |
6602 | begin | |
6603 | return | |
6604 | Make_Attribute_Reference (Loc, | |
6605 | Attribute_Name => Name_First, | |
6606 | Prefix => | |
9dfe12ae | 6607 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 6608 | Expressions => New_List ( |
6609 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 6610 | end Get_N_First; |
6611 | ||
6612 | ---------------- | |
6613 | -- Get_N_Last -- | |
6614 | ---------------- | |
6615 | ||
6616 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is | |
6617 | begin | |
6618 | return | |
6619 | Make_Attribute_Reference (Loc, | |
6620 | Attribute_Name => Name_Last, | |
6621 | Prefix => | |
9dfe12ae | 6622 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 6623 | Expressions => New_List ( |
6624 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 6625 | end Get_N_Last; |
6626 | ||
6627 | ------------------ | |
6628 | -- Range_E_Cond -- | |
6629 | ------------------ | |
6630 | ||
6631 | function Range_E_Cond | |
6632 | (Exptyp : Entity_Id; | |
6633 | Typ : Entity_Id; | |
314a23b6 | 6634 | Indx : Nat) return Node_Id |
ee6ba406 | 6635 | is |
6636 | begin | |
6637 | return | |
6638 | Make_Or_Else (Loc, | |
6639 | Left_Opnd => | |
6640 | Make_Op_Lt (Loc, | |
3cb12758 | 6641 | Left_Opnd => |
6642 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First), | |
6643 | Right_Opnd => | |
6644 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
ee6ba406 | 6645 | |
6646 | Right_Opnd => | |
6647 | Make_Op_Gt (Loc, | |
3cb12758 | 6648 | Left_Opnd => |
6649 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last), | |
6650 | Right_Opnd => | |
6651 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 6652 | end Range_E_Cond; |
6653 | ||
6654 | ------------------------ | |
6655 | -- Range_Equal_E_Cond -- | |
6656 | ------------------------ | |
6657 | ||
6658 | function Range_Equal_E_Cond | |
6659 | (Exptyp : Entity_Id; | |
6660 | Typ : Entity_Id; | |
314a23b6 | 6661 | Indx : Nat) return Node_Id |
ee6ba406 | 6662 | is |
6663 | begin | |
6664 | return | |
6665 | Make_Or_Else (Loc, | |
6666 | Left_Opnd => | |
6667 | Make_Op_Ne (Loc, | |
3cb12758 | 6668 | Left_Opnd => |
6669 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First), | |
6670 | Right_Opnd => | |
6671 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
6672 | ||
ee6ba406 | 6673 | Right_Opnd => |
6674 | Make_Op_Ne (Loc, | |
3cb12758 | 6675 | Left_Opnd => |
6676 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last), | |
6677 | Right_Opnd => | |
6678 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 6679 | end Range_Equal_E_Cond; |
6680 | ||
6681 | ------------------ | |
6682 | -- Range_N_Cond -- | |
6683 | ------------------ | |
6684 | ||
6685 | function Range_N_Cond | |
6686 | (Expr : Node_Id; | |
6687 | Typ : Entity_Id; | |
314a23b6 | 6688 | Indx : Nat) return Node_Id |
ee6ba406 | 6689 | is |
6690 | begin | |
6691 | return | |
6692 | Make_Or_Else (Loc, | |
6693 | Left_Opnd => | |
6694 | Make_Op_Lt (Loc, | |
3cb12758 | 6695 | Left_Opnd => |
6696 | Get_N_First (Expr, Indx), | |
6697 | Right_Opnd => | |
6698 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
ee6ba406 | 6699 | |
6700 | Right_Opnd => | |
6701 | Make_Op_Gt (Loc, | |
3cb12758 | 6702 | Left_Opnd => |
6703 | Get_N_Last (Expr, Indx), | |
6704 | Right_Opnd => | |
6705 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 6706 | end Range_N_Cond; |
6707 | ||
6708 | -- Start of processing for Selected_Range_Checks | |
6709 | ||
6710 | begin | |
6711 | if not Expander_Active then | |
6712 | return Ret_Result; | |
6713 | end if; | |
6714 | ||
6715 | if Target_Typ = Any_Type | |
6716 | or else Target_Typ = Any_Composite | |
6717 | or else Raises_Constraint_Error (Ck_Node) | |
6718 | then | |
6719 | return Ret_Result; | |
6720 | end if; | |
6721 | ||
6722 | if No (Wnode) then | |
6723 | Wnode := Ck_Node; | |
6724 | end if; | |
6725 | ||
6726 | T_Typ := Target_Typ; | |
6727 | ||
6728 | if No (Source_Typ) then | |
6729 | S_Typ := Etype (Ck_Node); | |
6730 | else | |
6731 | S_Typ := Source_Typ; | |
6732 | end if; | |
6733 | ||
6734 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
6735 | return Ret_Result; | |
6736 | end if; | |
6737 | ||
6738 | -- The order of evaluating T_Typ before S_Typ seems to be critical | |
6739 | -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed | |
6740 | -- in, and since Node can be an N_Range node, it might be invalid. | |
6741 | -- Should there be an assert check somewhere for taking the Etype of | |
6742 | -- an N_Range node ??? | |
6743 | ||
6744 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
6745 | S_Typ := Designated_Type (S_Typ); | |
6746 | T_Typ := Designated_Type (T_Typ); | |
6747 | Do_Access := True; | |
6748 | ||
2af58f67 | 6749 | -- A simple optimization for the null case |
ee6ba406 | 6750 | |
2af58f67 | 6751 | if Known_Null (Ck_Node) then |
ee6ba406 | 6752 | return Ret_Result; |
6753 | end if; | |
6754 | end if; | |
6755 | ||
6756 | -- For an N_Range Node, check for a null range and then if not | |
6757 | -- null generate a range check action. | |
6758 | ||
6759 | if Nkind (Ck_Node) = N_Range then | |
6760 | ||
6761 | -- There's no point in checking a range against itself | |
6762 | ||
6763 | if Ck_Node = Scalar_Range (T_Typ) then | |
6764 | return Ret_Result; | |
6765 | end if; | |
6766 | ||
6767 | declare | |
6768 | T_LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
6769 | T_HB : constant Node_Id := Type_High_Bound (T_Typ); | |
eefa141b | 6770 | Known_T_LB : constant Boolean := Compile_Time_Known_Value (T_LB); |
6771 | Known_T_HB : constant Boolean := Compile_Time_Known_Value (T_HB); | |
ee6ba406 | 6772 | |
eefa141b | 6773 | LB : Node_Id := Low_Bound (Ck_Node); |
6774 | HB : Node_Id := High_Bound (Ck_Node); | |
6775 | Known_LB : Boolean; | |
6776 | Known_HB : Boolean; | |
6777 | ||
6778 | Null_Range : Boolean; | |
ee6ba406 | 6779 | Out_Of_Range_L : Boolean; |
6780 | Out_Of_Range_H : Boolean; | |
6781 | ||
6782 | begin | |
eefa141b | 6783 | -- Compute what is known at compile time |
6784 | ||
6785 | if Known_T_LB and Known_T_HB then | |
6786 | if Compile_Time_Known_Value (LB) then | |
6787 | Known_LB := True; | |
6788 | ||
6789 | -- There's no point in checking that a bound is within its | |
6790 | -- own range so pretend that it is known in this case. First | |
6791 | -- deal with low bound. | |
6792 | ||
6793 | elsif Ekind (Etype (LB)) = E_Signed_Integer_Subtype | |
6794 | and then Scalar_Range (Etype (LB)) = Scalar_Range (T_Typ) | |
6795 | then | |
6796 | LB := T_LB; | |
6797 | Known_LB := True; | |
6798 | ||
6799 | else | |
6800 | Known_LB := False; | |
6801 | end if; | |
6802 | ||
6803 | -- Likewise for the high bound | |
6804 | ||
6805 | if Compile_Time_Known_Value (HB) then | |
6806 | Known_HB := True; | |
6807 | ||
6808 | elsif Ekind (Etype (HB)) = E_Signed_Integer_Subtype | |
6809 | and then Scalar_Range (Etype (HB)) = Scalar_Range (T_Typ) | |
6810 | then | |
6811 | HB := T_HB; | |
6812 | Known_HB := True; | |
6813 | ||
6814 | else | |
6815 | Known_HB := False; | |
6816 | end if; | |
6817 | end if; | |
6818 | ||
6819 | -- Check for case where everything is static and we can do the | |
6820 | -- check at compile time. This is skipped if we have an access | |
6821 | -- type, since the access value may be null. | |
6822 | ||
6823 | -- ??? This code can be improved since you only need to know that | |
6824 | -- the two respective bounds (LB & T_LB or HB & T_HB) are known at | |
6825 | -- compile time to emit pertinent messages. | |
6826 | ||
6827 | if Known_T_LB and Known_T_HB and Known_LB and Known_HB | |
6828 | and not Do_Access | |
ee6ba406 | 6829 | then |
6830 | -- Floating-point case | |
6831 | ||
6832 | if Is_Floating_Point_Type (S_Typ) then | |
6833 | Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB); | |
6834 | Out_Of_Range_L := | |
6835 | (Expr_Value_R (LB) < Expr_Value_R (T_LB)) | |
eefa141b | 6836 | or else |
ee6ba406 | 6837 | (Expr_Value_R (LB) > Expr_Value_R (T_HB)); |
6838 | ||
6839 | Out_Of_Range_H := | |
6840 | (Expr_Value_R (HB) > Expr_Value_R (T_HB)) | |
eefa141b | 6841 | or else |
ee6ba406 | 6842 | (Expr_Value_R (HB) < Expr_Value_R (T_LB)); |
6843 | ||
6844 | -- Fixed or discrete type case | |
6845 | ||
6846 | else | |
6847 | Null_Range := Expr_Value (HB) < Expr_Value (LB); | |
6848 | Out_Of_Range_L := | |
6849 | (Expr_Value (LB) < Expr_Value (T_LB)) | |
eefa141b | 6850 | or else |
ee6ba406 | 6851 | (Expr_Value (LB) > Expr_Value (T_HB)); |
6852 | ||
6853 | Out_Of_Range_H := | |
6854 | (Expr_Value (HB) > Expr_Value (T_HB)) | |
eefa141b | 6855 | or else |
ee6ba406 | 6856 | (Expr_Value (HB) < Expr_Value (T_LB)); |
6857 | end if; | |
6858 | ||
6859 | if not Null_Range then | |
6860 | if Out_Of_Range_L then | |
6861 | if No (Warn_Node) then | |
6862 | Add_Check | |
6863 | (Compile_Time_Constraint_Error | |
6864 | (Low_Bound (Ck_Node), | |
6865 | "static value out of range of}?", T_Typ)); | |
6866 | ||
6867 | else | |
6868 | Add_Check | |
6869 | (Compile_Time_Constraint_Error | |
6870 | (Wnode, | |
6871 | "static range out of bounds of}?", T_Typ)); | |
6872 | end if; | |
6873 | end if; | |
6874 | ||
6875 | if Out_Of_Range_H then | |
6876 | if No (Warn_Node) then | |
6877 | Add_Check | |
6878 | (Compile_Time_Constraint_Error | |
6879 | (High_Bound (Ck_Node), | |
6880 | "static value out of range of}?", T_Typ)); | |
6881 | ||
6882 | else | |
6883 | Add_Check | |
6884 | (Compile_Time_Constraint_Error | |
6885 | (Wnode, | |
6886 | "static range out of bounds of}?", T_Typ)); | |
6887 | end if; | |
6888 | end if; | |
ee6ba406 | 6889 | end if; |
6890 | ||
6891 | else | |
6892 | declare | |
6893 | LB : Node_Id := Low_Bound (Ck_Node); | |
6894 | HB : Node_Id := High_Bound (Ck_Node); | |
6895 | ||
6896 | begin | |
feff2f05 | 6897 | -- If either bound is a discriminant and we are within the |
6898 | -- record declaration, it is a use of the discriminant in a | |
6899 | -- constraint of a component, and nothing can be checked | |
6900 | -- here. The check will be emitted within the init proc. | |
6901 | -- Before then, the discriminal has no real meaning. | |
6902 | -- Similarly, if the entity is a discriminal, there is no | |
6903 | -- check to perform yet. | |
6904 | ||
6905 | -- The same holds within a discriminated synchronized type, | |
6906 | -- where the discriminant may constrain a component or an | |
6907 | -- entry family. | |
ee6ba406 | 6908 | |
6909 | if Nkind (LB) = N_Identifier | |
0577b0b1 | 6910 | and then Denotes_Discriminant (LB, True) |
ee6ba406 | 6911 | then |
0577b0b1 | 6912 | if Current_Scope = Scope (Entity (LB)) |
6913 | or else Is_Concurrent_Type (Current_Scope) | |
6914 | or else Ekind (Entity (LB)) /= E_Discriminant | |
6915 | then | |
ee6ba406 | 6916 | return Ret_Result; |
6917 | else | |
6918 | LB := | |
6919 | New_Occurrence_Of (Discriminal (Entity (LB)), Loc); | |
6920 | end if; | |
6921 | end if; | |
6922 | ||
6923 | if Nkind (HB) = N_Identifier | |
0577b0b1 | 6924 | and then Denotes_Discriminant (HB, True) |
ee6ba406 | 6925 | then |
0577b0b1 | 6926 | if Current_Scope = Scope (Entity (HB)) |
6927 | or else Is_Concurrent_Type (Current_Scope) | |
6928 | or else Ekind (Entity (HB)) /= E_Discriminant | |
6929 | then | |
ee6ba406 | 6930 | return Ret_Result; |
6931 | else | |
6932 | HB := | |
6933 | New_Occurrence_Of (Discriminal (Entity (HB)), Loc); | |
6934 | end if; | |
6935 | end if; | |
6936 | ||
6937 | Cond := Discrete_Range_Cond (Ck_Node, T_Typ); | |
6938 | Set_Paren_Count (Cond, 1); | |
6939 | ||
6940 | Cond := | |
6941 | Make_And_Then (Loc, | |
6942 | Left_Opnd => | |
6943 | Make_Op_Ge (Loc, | |
9dfe12ae | 6944 | Left_Opnd => Duplicate_Subexpr_No_Checks (HB), |
6945 | Right_Opnd => Duplicate_Subexpr_No_Checks (LB)), | |
ee6ba406 | 6946 | Right_Opnd => Cond); |
6947 | end; | |
ee6ba406 | 6948 | end if; |
6949 | end; | |
6950 | ||
6951 | elsif Is_Scalar_Type (S_Typ) then | |
6952 | ||
6953 | -- This somewhat duplicates what Apply_Scalar_Range_Check does, | |
6954 | -- except the above simply sets a flag in the node and lets | |
6955 | -- gigi generate the check base on the Etype of the expression. | |
6956 | -- Sometimes, however we want to do a dynamic check against an | |
6957 | -- arbitrary target type, so we do that here. | |
6958 | ||
6959 | if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then | |
6960 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
6961 | ||
6962 | -- For literals, we can tell if the constraint error will be | |
6963 | -- raised at compile time, so we never need a dynamic check, but | |
6964 | -- if the exception will be raised, then post the usual warning, | |
6965 | -- and replace the literal with a raise constraint error | |
6966 | -- expression. As usual, skip this for access types | |
6967 | ||
6968 | elsif Compile_Time_Known_Value (Ck_Node) | |
6969 | and then not Do_Access | |
6970 | then | |
6971 | declare | |
6972 | LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
6973 | UB : constant Node_Id := Type_High_Bound (T_Typ); | |
6974 | ||
6975 | Out_Of_Range : Boolean; | |
6976 | Static_Bounds : constant Boolean := | |
6977 | Compile_Time_Known_Value (LB) | |
6978 | and Compile_Time_Known_Value (UB); | |
6979 | ||
6980 | begin | |
6981 | -- Following range tests should use Sem_Eval routine ??? | |
6982 | ||
6983 | if Static_Bounds then | |
6984 | if Is_Floating_Point_Type (S_Typ) then | |
6985 | Out_Of_Range := | |
6986 | (Expr_Value_R (Ck_Node) < Expr_Value_R (LB)) | |
6987 | or else | |
6988 | (Expr_Value_R (Ck_Node) > Expr_Value_R (UB)); | |
6989 | ||
eefa141b | 6990 | -- Fixed or discrete type |
6991 | ||
6992 | else | |
ee6ba406 | 6993 | Out_Of_Range := |
6994 | Expr_Value (Ck_Node) < Expr_Value (LB) | |
6995 | or else | |
6996 | Expr_Value (Ck_Node) > Expr_Value (UB); | |
6997 | end if; | |
6998 | ||
eefa141b | 6999 | -- Bounds of the type are static and the literal is out of |
7000 | -- range so output a warning message. | |
ee6ba406 | 7001 | |
7002 | if Out_Of_Range then | |
7003 | if No (Warn_Node) then | |
7004 | Add_Check | |
7005 | (Compile_Time_Constraint_Error | |
7006 | (Ck_Node, | |
7007 | "static value out of range of}?", T_Typ)); | |
7008 | ||
7009 | else | |
7010 | Add_Check | |
7011 | (Compile_Time_Constraint_Error | |
7012 | (Wnode, | |
7013 | "static value out of range of}?", T_Typ)); | |
7014 | end if; | |
7015 | end if; | |
7016 | ||
7017 | else | |
7018 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
7019 | end if; | |
7020 | end; | |
7021 | ||
7022 | -- Here for the case of a non-static expression, we need a runtime | |
7023 | -- check unless the source type range is guaranteed to be in the | |
7024 | -- range of the target type. | |
7025 | ||
7026 | else | |
7a1dabb3 | 7027 | if not In_Subrange_Of (S_Typ, T_Typ) then |
ee6ba406 | 7028 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); |
7029 | end if; | |
7030 | end if; | |
7031 | end if; | |
7032 | ||
7033 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
7034 | if Is_Constrained (T_Typ) then | |
7035 | ||
7036 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
7037 | Exptyp := Get_Actual_Subtype (Expr_Actual); | |
7038 | ||
7039 | if Is_Access_Type (Exptyp) then | |
7040 | Exptyp := Designated_Type (Exptyp); | |
7041 | end if; | |
7042 | ||
7043 | -- String_Literal case. This needs to be handled specially be- | |
7044 | -- cause no index types are available for string literals. The | |
7045 | -- condition is simply: | |
7046 | ||
7047 | -- T_Typ'Length = string-literal-length | |
7048 | ||
7049 | if Nkind (Expr_Actual) = N_String_Literal then | |
7050 | null; | |
7051 | ||
7052 | -- General array case. Here we have a usable actual subtype for | |
7053 | -- the expression, and the condition is built from the two types | |
7054 | ||
7055 | -- T_Typ'First < Exptyp'First or else | |
7056 | -- T_Typ'Last > Exptyp'Last or else | |
7057 | -- T_Typ'First(1) < Exptyp'First(1) or else | |
7058 | -- T_Typ'Last(1) > Exptyp'Last(1) or else | |
7059 | -- ... | |
7060 | ||
7061 | elsif Is_Constrained (Exptyp) then | |
7062 | declare | |
9dfe12ae | 7063 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
7064 | ||
ee6ba406 | 7065 | L_Index : Node_Id; |
7066 | R_Index : Node_Id; | |
ee6ba406 | 7067 | |
7068 | begin | |
7069 | L_Index := First_Index (T_Typ); | |
7070 | R_Index := First_Index (Exptyp); | |
7071 | ||
7072 | for Indx in 1 .. Ndims loop | |
7073 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 7074 | or else |
7075 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 7076 | then |
ee6ba406 | 7077 | -- Deal with compile time length check. Note that we |
7078 | -- skip this in the access case, because the access | |
7079 | -- value may be null, so we cannot know statically. | |
7080 | ||
7081 | if not | |
7082 | Subtypes_Statically_Match | |
7083 | (Etype (L_Index), Etype (R_Index)) | |
7084 | then | |
7085 | -- If the target type is constrained then we | |
7086 | -- have to check for exact equality of bounds | |
7087 | -- (required for qualified expressions). | |
7088 | ||
7089 | if Is_Constrained (T_Typ) then | |
7090 | Evolve_Or_Else | |
7091 | (Cond, | |
7092 | Range_Equal_E_Cond (Exptyp, T_Typ, Indx)); | |
ee6ba406 | 7093 | else |
7094 | Evolve_Or_Else | |
7095 | (Cond, Range_E_Cond (Exptyp, T_Typ, Indx)); | |
7096 | end if; | |
7097 | end if; | |
7098 | ||
7099 | Next (L_Index); | |
7100 | Next (R_Index); | |
ee6ba406 | 7101 | end if; |
7102 | end loop; | |
7103 | end; | |
7104 | ||
7105 | -- Handle cases where we do not get a usable actual subtype that | |
7106 | -- is constrained. This happens for example in the function call | |
7107 | -- and explicit dereference cases. In these cases, we have to get | |
7108 | -- the length or range from the expression itself, making sure we | |
7109 | -- do not evaluate it more than once. | |
7110 | ||
7111 | -- Here Ck_Node is the original expression, or more properly the | |
7112 | -- result of applying Duplicate_Expr to the original tree, | |
7113 | -- forcing the result to be a name. | |
7114 | ||
7115 | else | |
7116 | declare | |
9dfe12ae | 7117 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 7118 | |
7119 | begin | |
7120 | -- Build the condition for the explicit dereference case | |
7121 | ||
7122 | for Indx in 1 .. Ndims loop | |
7123 | Evolve_Or_Else | |
7124 | (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx)); | |
7125 | end loop; | |
7126 | end; | |
ee6ba406 | 7127 | end if; |
7128 | ||
7129 | else | |
feff2f05 | 7130 | -- For a conversion to an unconstrained array type, generate an |
7131 | -- Action to check that the bounds of the source value are within | |
7132 | -- the constraints imposed by the target type (RM 4.6(38)). No | |
7133 | -- check is needed for a conversion to an access to unconstrained | |
7134 | -- array type, as 4.6(24.15/2) requires the designated subtypes | |
7135 | -- of the two access types to statically match. | |
7136 | ||
7137 | if Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
7138 | and then not Do_Access | |
7139 | then | |
ee6ba406 | 7140 | declare |
7141 | Opnd_Index : Node_Id; | |
7142 | Targ_Index : Node_Id; | |
00c403ee | 7143 | Opnd_Range : Node_Id; |
ee6ba406 | 7144 | |
7145 | begin | |
feff2f05 | 7146 | Opnd_Index := First_Index (Get_Actual_Subtype (Ck_Node)); |
ee6ba406 | 7147 | Targ_Index := First_Index (T_Typ); |
00c403ee | 7148 | while Present (Opnd_Index) loop |
7149 | ||
7150 | -- If the index is a range, use its bounds. If it is an | |
7151 | -- entity (as will be the case if it is a named subtype | |
7152 | -- or an itype created for a slice) retrieve its range. | |
7153 | ||
7154 | if Is_Entity_Name (Opnd_Index) | |
7155 | and then Is_Type (Entity (Opnd_Index)) | |
7156 | then | |
7157 | Opnd_Range := Scalar_Range (Entity (Opnd_Index)); | |
7158 | else | |
7159 | Opnd_Range := Opnd_Index; | |
7160 | end if; | |
7161 | ||
7162 | if Nkind (Opnd_Range) = N_Range then | |
9c486805 | 7163 | if Is_In_Range |
7164 | (Low_Bound (Opnd_Range), Etype (Targ_Index), | |
7165 | Assume_Valid => True) | |
ee6ba406 | 7166 | and then |
7167 | Is_In_Range | |
9c486805 | 7168 | (High_Bound (Opnd_Range), Etype (Targ_Index), |
7169 | Assume_Valid => True) | |
ee6ba406 | 7170 | then |
7171 | null; | |
7172 | ||
feff2f05 | 7173 | -- If null range, no check needed |
f2a06be9 | 7174 | |
9dfe12ae | 7175 | elsif |
00c403ee | 7176 | Compile_Time_Known_Value (High_Bound (Opnd_Range)) |
9dfe12ae | 7177 | and then |
00c403ee | 7178 | Compile_Time_Known_Value (Low_Bound (Opnd_Range)) |
9dfe12ae | 7179 | and then |
00c403ee | 7180 | Expr_Value (High_Bound (Opnd_Range)) < |
7181 | Expr_Value (Low_Bound (Opnd_Range)) | |
9dfe12ae | 7182 | then |
7183 | null; | |
7184 | ||
ee6ba406 | 7185 | elsif Is_Out_Of_Range |
9c486805 | 7186 | (Low_Bound (Opnd_Range), Etype (Targ_Index), |
7187 | Assume_Valid => True) | |
ee6ba406 | 7188 | or else |
7189 | Is_Out_Of_Range | |
9c486805 | 7190 | (High_Bound (Opnd_Range), Etype (Targ_Index), |
7191 | Assume_Valid => True) | |
ee6ba406 | 7192 | then |
7193 | Add_Check | |
7194 | (Compile_Time_Constraint_Error | |
7195 | (Wnode, "value out of range of}?", T_Typ)); | |
7196 | ||
7197 | else | |
7198 | Evolve_Or_Else | |
7199 | (Cond, | |
7200 | Discrete_Range_Cond | |
00c403ee | 7201 | (Opnd_Range, Etype (Targ_Index))); |
ee6ba406 | 7202 | end if; |
7203 | end if; | |
7204 | ||
7205 | Next_Index (Opnd_Index); | |
7206 | Next_Index (Targ_Index); | |
7207 | end loop; | |
7208 | end; | |
7209 | end if; | |
7210 | end if; | |
7211 | end if; | |
7212 | ||
7213 | -- Construct the test and insert into the tree | |
7214 | ||
7215 | if Present (Cond) then | |
7216 | if Do_Access then | |
7217 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
7218 | end if; | |
7219 | ||
f15731c4 | 7220 | Add_Check |
7221 | (Make_Raise_Constraint_Error (Loc, | |
eefa141b | 7222 | Condition => Cond, |
7223 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 7224 | end if; |
7225 | ||
7226 | return Ret_Result; | |
ee6ba406 | 7227 | end Selected_Range_Checks; |
7228 | ||
7229 | ------------------------------- | |
7230 | -- Storage_Checks_Suppressed -- | |
7231 | ------------------------------- | |
7232 | ||
7233 | function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is | |
7234 | begin | |
9dfe12ae | 7235 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
7236 | return Is_Check_Suppressed (E, Storage_Check); | |
7237 | else | |
7238 | return Scope_Suppress (Storage_Check); | |
7239 | end if; | |
ee6ba406 | 7240 | end Storage_Checks_Suppressed; |
7241 | ||
7242 | --------------------------- | |
7243 | -- Tag_Checks_Suppressed -- | |
7244 | --------------------------- | |
7245 | ||
7246 | function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is | |
7247 | begin | |
9dfe12ae | 7248 | if Present (E) then |
7249 | if Kill_Tag_Checks (E) then | |
7250 | return True; | |
7251 | elsif Checks_May_Be_Suppressed (E) then | |
7252 | return Is_Check_Suppressed (E, Tag_Check); | |
7253 | end if; | |
7254 | end if; | |
7255 | ||
7256 | return Scope_Suppress (Tag_Check); | |
ee6ba406 | 7257 | end Tag_Checks_Suppressed; |
7258 | ||
0577b0b1 | 7259 | -------------------------- |
7260 | -- Validity_Check_Range -- | |
7261 | -------------------------- | |
7262 | ||
7263 | procedure Validity_Check_Range (N : Node_Id) is | |
7264 | begin | |
7265 | if Validity_Checks_On and Validity_Check_Operands then | |
7266 | if Nkind (N) = N_Range then | |
7267 | Ensure_Valid (Low_Bound (N)); | |
7268 | Ensure_Valid (High_Bound (N)); | |
7269 | end if; | |
7270 | end if; | |
7271 | end Validity_Check_Range; | |
7272 | ||
7273 | -------------------------------- | |
7274 | -- Validity_Checks_Suppressed -- | |
7275 | -------------------------------- | |
7276 | ||
7277 | function Validity_Checks_Suppressed (E : Entity_Id) return Boolean is | |
7278 | begin | |
7279 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
7280 | return Is_Check_Suppressed (E, Validity_Check); | |
7281 | else | |
7282 | return Scope_Suppress (Validity_Check); | |
7283 | end if; | |
7284 | end Validity_Checks_Suppressed; | |
7285 | ||
ee6ba406 | 7286 | end Checks; |