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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 | -- -- | |
ce7498d3 | 9 | -- Copyright (C) 1992-2008, 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; | |
00c403ee | 31 | with Exp_Ch11; use Exp_Ch11; |
05fcfafb | 32 | with Exp_Pakd; use Exp_Pakd; |
ee6ba406 | 33 | with Exp_Util; use Exp_Util; |
34 | with Elists; use Elists; | |
5329ca64 | 35 | with Eval_Fat; use Eval_Fat; |
ee6ba406 | 36 | with Freeze; use Freeze; |
9dfe12ae | 37 | with Lib; use Lib; |
ee6ba406 | 38 | with Nlists; use Nlists; |
39 | with Nmake; use Nmake; | |
40 | with Opt; use Opt; | |
9dfe12ae | 41 | with Output; use Output; |
c2b56224 | 42 | with Restrict; use Restrict; |
1e16c51c | 43 | with Rident; use Rident; |
ee6ba406 | 44 | with Rtsfind; use Rtsfind; |
45 | with Sem; use Sem; | |
46 | with Sem_Eval; use Sem_Eval; | |
00f91aef | 47 | with Sem_Ch3; use Sem_Ch3; |
9dfe12ae | 48 | with Sem_Ch8; use Sem_Ch8; |
ee6ba406 | 49 | with Sem_Res; use Sem_Res; |
50 | with Sem_Util; use Sem_Util; | |
51 | with Sem_Warn; use Sem_Warn; | |
52 | with Sinfo; use Sinfo; | |
9dfe12ae | 53 | with Sinput; use Sinput; |
ee6ba406 | 54 | with Snames; use Snames; |
9dfe12ae | 55 | with Sprint; use Sprint; |
ee6ba406 | 56 | with Stand; use Stand; |
f15731c4 | 57 | with Targparm; use Targparm; |
ee6ba406 | 58 | with Tbuild; use Tbuild; |
59 | with Ttypes; use Ttypes; | |
60 | with Urealp; use Urealp; | |
61 | with Validsw; use Validsw; | |
62 | ||
63 | package body Checks is | |
64 | ||
65 | -- General note: many of these routines are concerned with generating | |
66 | -- checking code to make sure that constraint error is raised at runtime. | |
67 | -- Clearly this code is only needed if the expander is active, since | |
68 | -- otherwise we will not be generating code or going into the runtime | |
69 | -- execution anyway. | |
70 | ||
71 | -- We therefore disconnect most of these checks if the expander is | |
72 | -- inactive. This has the additional benefit that we do not need to | |
73 | -- worry about the tree being messed up by previous errors (since errors | |
74 | -- turn off expansion anyway). | |
75 | ||
76 | -- There are a few exceptions to the above rule. For instance routines | |
77 | -- such as Apply_Scalar_Range_Check that do not insert any code can be | |
78 | -- safely called even when the Expander is inactive (but Errors_Detected | |
79 | -- is 0). The benefit of executing this code when expansion is off, is | |
80 | -- the ability to emit constraint error warning for static expressions | |
81 | -- even when we are not generating code. | |
82 | ||
9dfe12ae | 83 | ------------------------------------- |
84 | -- Suppression of Redundant Checks -- | |
85 | ------------------------------------- | |
86 | ||
87 | -- This unit implements a limited circuit for removal of redundant | |
88 | -- checks. The processing is based on a tracing of simple sequential | |
89 | -- flow. For any sequence of statements, we save expressions that are | |
90 | -- marked to be checked, and then if the same expression appears later | |
91 | -- with the same check, then under certain circumstances, the second | |
92 | -- check can be suppressed. | |
93 | ||
94 | -- Basically, we can suppress the check if we know for certain that | |
95 | -- the previous expression has been elaborated (together with its | |
96 | -- check), and we know that the exception frame is the same, and that | |
97 | -- nothing has happened to change the result of the exception. | |
98 | ||
99 | -- Let us examine each of these three conditions in turn to describe | |
100 | -- how we ensure that this condition is met. | |
101 | ||
102 | -- First, we need to know for certain that the previous expression has | |
103 | -- been executed. This is done principly by the mechanism of calling | |
104 | -- Conditional_Statements_Begin at the start of any statement sequence | |
105 | -- and Conditional_Statements_End at the end. The End call causes all | |
106 | -- checks remembered since the Begin call to be discarded. This does | |
107 | -- miss a few cases, notably the case of a nested BEGIN-END block with | |
108 | -- no exception handlers. But the important thing is to be conservative. | |
109 | -- The other protection is that all checks are discarded if a label | |
110 | -- is encountered, since then the assumption of sequential execution | |
111 | -- is violated, and we don't know enough about the flow. | |
112 | ||
113 | -- Second, we need to know that the exception frame is the same. We | |
114 | -- do this by killing all remembered checks when we enter a new frame. | |
115 | -- Again, that's over-conservative, but generally the cases we can help | |
116 | -- with are pretty local anyway (like the body of a loop for example). | |
117 | ||
118 | -- Third, we must be sure to forget any checks which are no longer valid. | |
119 | -- This is done by two mechanisms, first the Kill_Checks_Variable call is | |
120 | -- used to note any changes to local variables. We only attempt to deal | |
121 | -- with checks involving local variables, so we do not need to worry | |
122 | -- about global variables. Second, a call to any non-global procedure | |
123 | -- causes us to abandon all stored checks, since such a all may affect | |
124 | -- the values of any local variables. | |
125 | ||
126 | -- The following define the data structures used to deal with remembering | |
127 | -- checks so that redundant checks can be eliminated as described above. | |
128 | ||
129 | -- Right now, the only expressions that we deal with are of the form of | |
130 | -- simple local objects (either declared locally, or IN parameters) or | |
131 | -- such objects plus/minus a compile time known constant. We can do | |
132 | -- more later on if it seems worthwhile, but this catches many simple | |
133 | -- cases in practice. | |
134 | ||
135 | -- The following record type reflects a single saved check. An entry | |
136 | -- is made in the stack of saved checks if and only if the expression | |
137 | -- has been elaborated with the indicated checks. | |
138 | ||
139 | type Saved_Check is record | |
140 | Killed : Boolean; | |
141 | -- Set True if entry is killed by Kill_Checks | |
142 | ||
143 | Entity : Entity_Id; | |
144 | -- The entity involved in the expression that is checked | |
145 | ||
146 | Offset : Uint; | |
147 | -- A compile time value indicating the result of adding or | |
148 | -- subtracting a compile time value. This value is to be | |
149 | -- added to the value of the Entity. A value of zero is | |
150 | -- used for the case of a simple entity reference. | |
151 | ||
152 | Check_Type : Character; | |
153 | -- This is set to 'R' for a range check (in which case Target_Type | |
154 | -- is set to the target type for the range check) or to 'O' for an | |
155 | -- overflow check (in which case Target_Type is set to Empty). | |
156 | ||
157 | Target_Type : Entity_Id; | |
158 | -- Used only if Do_Range_Check is set. Records the target type for | |
159 | -- the check. We need this, because a check is a duplicate only if | |
160 | -- it has a the same target type (or more accurately one with a | |
161 | -- range that is smaller or equal to the stored target type of a | |
162 | -- saved check). | |
163 | end record; | |
164 | ||
165 | -- The following table keeps track of saved checks. Rather than use an | |
166 | -- extensible table. We just use a table of fixed size, and we discard | |
167 | -- any saved checks that do not fit. That's very unlikely to happen and | |
168 | -- this is only an optimization in any case. | |
169 | ||
170 | Saved_Checks : array (Int range 1 .. 200) of Saved_Check; | |
171 | -- Array of saved checks | |
172 | ||
173 | Num_Saved_Checks : Nat := 0; | |
174 | -- Number of saved checks | |
175 | ||
176 | -- The following stack keeps track of statement ranges. It is treated | |
177 | -- as a stack. When Conditional_Statements_Begin is called, an entry | |
178 | -- is pushed onto this stack containing the value of Num_Saved_Checks | |
179 | -- at the time of the call. Then when Conditional_Statements_End is | |
180 | -- called, this value is popped off and used to reset Num_Saved_Checks. | |
181 | ||
182 | -- Note: again, this is a fixed length stack with a size that should | |
183 | -- always be fine. If the value of the stack pointer goes above the | |
184 | -- limit, then we just forget all saved checks. | |
185 | ||
186 | Saved_Checks_Stack : array (Int range 1 .. 100) of Nat; | |
187 | Saved_Checks_TOS : Nat := 0; | |
188 | ||
189 | ----------------------- | |
190 | -- Local Subprograms -- | |
191 | ----------------------- | |
ee6ba406 | 192 | |
5329ca64 | 193 | procedure Apply_Float_Conversion_Check |
194 | (Ck_Node : Node_Id; | |
195 | Target_Typ : Entity_Id); | |
196 | -- The checks on a conversion from a floating-point type to an integer | |
197 | -- type are delicate. They have to be performed before conversion, they | |
198 | -- have to raise an exception when the operand is a NaN, and rounding must | |
199 | -- be taken into account to determine the safe bounds of the operand. | |
200 | ||
ee6ba406 | 201 | procedure Apply_Selected_Length_Checks |
202 | (Ck_Node : Node_Id; | |
203 | Target_Typ : Entity_Id; | |
204 | Source_Typ : Entity_Id; | |
205 | Do_Static : Boolean); | |
206 | -- This is the subprogram that does all the work for Apply_Length_Check | |
207 | -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as | |
208 | -- described for the above routines. The Do_Static flag indicates that | |
209 | -- only a static check is to be done. | |
210 | ||
211 | procedure Apply_Selected_Range_Checks | |
212 | (Ck_Node : Node_Id; | |
213 | Target_Typ : Entity_Id; | |
214 | Source_Typ : Entity_Id; | |
215 | Do_Static : Boolean); | |
216 | -- This is the subprogram that does all the work for Apply_Range_Check. | |
217 | -- Expr, Target_Typ and Source_Typ are as described for the above | |
218 | -- routine. The Do_Static flag indicates that only a static check is | |
219 | -- to be done. | |
220 | ||
2af58f67 | 221 | type Check_Type is new Check_Id range Access_Check .. Division_Check; |
13dbf220 | 222 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean; |
223 | -- This function is used to see if an access or division by zero check is | |
224 | -- needed. The check is to be applied to a single variable appearing in the | |
225 | -- source, and N is the node for the reference. If N is not of this form, | |
226 | -- True is returned with no further processing. If N is of the right form, | |
227 | -- then further processing determines if the given Check is needed. | |
228 | -- | |
229 | -- The particular circuit is to see if we have the case of a check that is | |
230 | -- not needed because it appears in the right operand of a short circuited | |
231 | -- conditional where the left operand guards the check. For example: | |
232 | -- | |
233 | -- if Var = 0 or else Q / Var > 12 then | |
234 | -- ... | |
235 | -- end if; | |
236 | -- | |
237 | -- In this example, the division check is not required. At the same time | |
238 | -- we can issue warnings for suspicious use of non-short-circuited forms, | |
239 | -- such as: | |
240 | -- | |
241 | -- if Var = 0 or Q / Var > 12 then | |
242 | -- ... | |
243 | -- end if; | |
244 | ||
9dfe12ae | 245 | procedure Find_Check |
246 | (Expr : Node_Id; | |
247 | Check_Type : Character; | |
248 | Target_Type : Entity_Id; | |
249 | Entry_OK : out Boolean; | |
250 | Check_Num : out Nat; | |
251 | Ent : out Entity_Id; | |
252 | Ofs : out Uint); | |
253 | -- This routine is used by Enable_Range_Check and Enable_Overflow_Check | |
254 | -- to see if a check is of the form for optimization, and if so, to see | |
255 | -- if it has already been performed. Expr is the expression to check, | |
256 | -- and Check_Type is 'R' for a range check, 'O' for an overflow check. | |
257 | -- Target_Type is the target type for a range check, and Empty for an | |
258 | -- overflow check. If the entry is not of the form for optimization, | |
259 | -- then Entry_OK is set to False, and the remaining out parameters | |
260 | -- are undefined. If the entry is OK, then Ent/Ofs are set to the | |
261 | -- entity and offset from the expression. Check_Num is the number of | |
262 | -- a matching saved entry in Saved_Checks, or zero if no such entry | |
263 | -- is located. | |
264 | ||
ee6ba406 | 265 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id; |
266 | -- If a discriminal is used in constraining a prival, Return reference | |
267 | -- to the discriminal of the protected body (which renames the parameter | |
268 | -- of the enclosing protected operation). This clumsy transformation is | |
269 | -- needed because privals are created too late and their actual subtypes | |
270 | -- are not available when analysing the bodies of the protected operations. | |
0577b0b1 | 271 | -- This function is called whenever the bound is an entity and the scope |
272 | -- indicates a protected operation. If the bound is an in-parameter of | |
273 | -- a protected operation that is not a prival, the function returns the | |
274 | -- bound itself. | |
ee6ba406 | 275 | -- To be cleaned up??? |
276 | ||
277 | function Guard_Access | |
278 | (Cond : Node_Id; | |
279 | Loc : Source_Ptr; | |
314a23b6 | 280 | Ck_Node : Node_Id) return Node_Id; |
ee6ba406 | 281 | -- In the access type case, guard the test with a test to ensure |
282 | -- that the access value is non-null, since the checks do not | |
283 | -- not apply to null access values. | |
284 | ||
285 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr); | |
286 | -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the | |
287 | -- Constraint_Error node. | |
288 | ||
0577b0b1 | 289 | function Range_Or_Validity_Checks_Suppressed |
290 | (Expr : Node_Id) return Boolean; | |
291 | -- Returns True if either range or validity checks or both are suppressed | |
292 | -- for the type of the given expression, or, if the expression is the name | |
293 | -- of an entity, if these checks are suppressed for the entity. | |
294 | ||
ee6ba406 | 295 | function Selected_Length_Checks |
296 | (Ck_Node : Node_Id; | |
297 | Target_Typ : Entity_Id; | |
298 | Source_Typ : Entity_Id; | |
314a23b6 | 299 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 300 | -- Like Apply_Selected_Length_Checks, except it doesn't modify |
301 | -- anything, just returns a list of nodes as described in the spec of | |
302 | -- this package for the Range_Check function. | |
303 | ||
304 | function Selected_Range_Checks | |
305 | (Ck_Node : Node_Id; | |
306 | Target_Typ : Entity_Id; | |
307 | Source_Typ : Entity_Id; | |
314a23b6 | 308 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 309 | -- Like Apply_Selected_Range_Checks, except it doesn't modify anything, |
310 | -- just returns a list of nodes as described in the spec of this package | |
311 | -- for the Range_Check function. | |
312 | ||
313 | ------------------------------ | |
314 | -- Access_Checks_Suppressed -- | |
315 | ------------------------------ | |
316 | ||
317 | function Access_Checks_Suppressed (E : Entity_Id) return Boolean is | |
318 | begin | |
9dfe12ae | 319 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
320 | return Is_Check_Suppressed (E, Access_Check); | |
321 | else | |
322 | return Scope_Suppress (Access_Check); | |
323 | end if; | |
ee6ba406 | 324 | end Access_Checks_Suppressed; |
325 | ||
326 | ------------------------------------- | |
327 | -- Accessibility_Checks_Suppressed -- | |
328 | ------------------------------------- | |
329 | ||
330 | function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is | |
331 | begin | |
9dfe12ae | 332 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
333 | return Is_Check_Suppressed (E, Accessibility_Check); | |
334 | else | |
335 | return Scope_Suppress (Accessibility_Check); | |
336 | end if; | |
ee6ba406 | 337 | end Accessibility_Checks_Suppressed; |
338 | ||
00c403ee | 339 | ----------------------------- |
340 | -- Activate_Division_Check -- | |
341 | ----------------------------- | |
342 | ||
343 | procedure Activate_Division_Check (N : Node_Id) is | |
344 | begin | |
345 | Set_Do_Division_Check (N, True); | |
346 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
347 | end Activate_Division_Check; | |
348 | ||
349 | ----------------------------- | |
350 | -- Activate_Overflow_Check -- | |
351 | ----------------------------- | |
352 | ||
353 | procedure Activate_Overflow_Check (N : Node_Id) is | |
354 | begin | |
355 | Set_Do_Overflow_Check (N, True); | |
356 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
357 | end Activate_Overflow_Check; | |
358 | ||
359 | -------------------------- | |
360 | -- Activate_Range_Check -- | |
361 | -------------------------- | |
362 | ||
363 | procedure Activate_Range_Check (N : Node_Id) is | |
364 | begin | |
365 | Set_Do_Range_Check (N, True); | |
366 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
367 | end Activate_Range_Check; | |
368 | ||
0577b0b1 | 369 | --------------------------------- |
370 | -- Alignment_Checks_Suppressed -- | |
371 | --------------------------------- | |
372 | ||
373 | function Alignment_Checks_Suppressed (E : Entity_Id) return Boolean is | |
374 | begin | |
375 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
376 | return Is_Check_Suppressed (E, Alignment_Check); | |
377 | else | |
378 | return Scope_Suppress (Alignment_Check); | |
379 | end if; | |
380 | end Alignment_Checks_Suppressed; | |
381 | ||
ee6ba406 | 382 | ------------------------- |
383 | -- Append_Range_Checks -- | |
384 | ------------------------- | |
385 | ||
386 | procedure Append_Range_Checks | |
387 | (Checks : Check_Result; | |
388 | Stmts : List_Id; | |
389 | Suppress_Typ : Entity_Id; | |
390 | Static_Sloc : Source_Ptr; | |
391 | Flag_Node : Node_Id) | |
392 | is | |
9dfe12ae | 393 | Internal_Flag_Node : constant Node_Id := Flag_Node; |
394 | Internal_Static_Sloc : constant Source_Ptr := Static_Sloc; | |
395 | ||
ee6ba406 | 396 | Checks_On : constant Boolean := |
397 | (not Index_Checks_Suppressed (Suppress_Typ)) | |
398 | or else | |
399 | (not Range_Checks_Suppressed (Suppress_Typ)); | |
400 | ||
401 | begin | |
402 | -- For now we just return if Checks_On is false, however this should | |
403 | -- be enhanced to check for an always True value in the condition | |
404 | -- and to generate a compilation warning??? | |
405 | ||
406 | if not Checks_On then | |
407 | return; | |
408 | end if; | |
409 | ||
410 | for J in 1 .. 2 loop | |
411 | exit when No (Checks (J)); | |
412 | ||
413 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
414 | and then Present (Condition (Checks (J))) | |
415 | then | |
416 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
417 | Append_To (Stmts, Checks (J)); | |
418 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
419 | end if; | |
420 | ||
421 | else | |
422 | Append_To | |
f15731c4 | 423 | (Stmts, |
424 | Make_Raise_Constraint_Error (Internal_Static_Sloc, | |
425 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 426 | end if; |
427 | end loop; | |
428 | end Append_Range_Checks; | |
429 | ||
430 | ------------------------ | |
431 | -- Apply_Access_Check -- | |
432 | ------------------------ | |
433 | ||
434 | procedure Apply_Access_Check (N : Node_Id) is | |
435 | P : constant Node_Id := Prefix (N); | |
436 | ||
437 | begin | |
13dbf220 | 438 | -- We do not need checks if we are not generating code (i.e. the |
439 | -- expander is not active). This is not just an optimization, there | |
440 | -- are cases (e.g. with pragma Debug) where generating the checks | |
441 | -- can cause real trouble). | |
284faf8b | 442 | |
84d0d4a5 | 443 | if not Expander_Active then |
13dbf220 | 444 | return; |
9dfe12ae | 445 | end if; |
ee6ba406 | 446 | |
84d0d4a5 | 447 | -- No check if short circuiting makes check unnecessary |
9dfe12ae | 448 | |
84d0d4a5 | 449 | if not Check_Needed (P, Access_Check) then |
450 | return; | |
ee6ba406 | 451 | end if; |
9dfe12ae | 452 | |
cc60bd16 | 453 | -- No check if accessing the Offset_To_Top component of a dispatch |
454 | -- table. They are safe by construction. | |
455 | ||
456 | if Present (Etype (P)) | |
457 | and then RTU_Loaded (Ada_Tags) | |
458 | and then RTE_Available (RE_Offset_To_Top_Ptr) | |
459 | and then Etype (P) = RTE (RE_Offset_To_Top_Ptr) | |
460 | then | |
461 | return; | |
462 | end if; | |
463 | ||
84d0d4a5 | 464 | -- Otherwise go ahead and install the check |
9dfe12ae | 465 | |
fa7497e8 | 466 | Install_Null_Excluding_Check (P); |
ee6ba406 | 467 | end Apply_Access_Check; |
468 | ||
469 | ------------------------------- | |
470 | -- Apply_Accessibility_Check -- | |
471 | ------------------------------- | |
472 | ||
473 | procedure Apply_Accessibility_Check (N : Node_Id; Typ : Entity_Id) is | |
474 | Loc : constant Source_Ptr := Sloc (N); | |
475 | Param_Ent : constant Entity_Id := Param_Entity (N); | |
476 | Param_Level : Node_Id; | |
477 | Type_Level : Node_Id; | |
478 | ||
479 | begin | |
480 | if Inside_A_Generic then | |
481 | return; | |
482 | ||
483 | -- Only apply the run-time check if the access parameter | |
484 | -- has an associated extra access level parameter and | |
485 | -- when the level of the type is less deep than the level | |
486 | -- of the access parameter. | |
487 | ||
488 | elsif Present (Param_Ent) | |
489 | and then Present (Extra_Accessibility (Param_Ent)) | |
490 | and then UI_Gt (Object_Access_Level (N), | |
491 | Type_Access_Level (Typ)) | |
492 | and then not Accessibility_Checks_Suppressed (Param_Ent) | |
493 | and then not Accessibility_Checks_Suppressed (Typ) | |
494 | then | |
495 | Param_Level := | |
496 | New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc); | |
497 | ||
498 | Type_Level := | |
499 | Make_Integer_Literal (Loc, Type_Access_Level (Typ)); | |
500 | ||
84d0d4a5 | 501 | -- Raise Program_Error if the accessibility level of the the access |
502 | -- parameter is deeper than the level of the target access type. | |
ee6ba406 | 503 | |
504 | Insert_Action (N, | |
505 | Make_Raise_Program_Error (Loc, | |
506 | Condition => | |
507 | Make_Op_Gt (Loc, | |
508 | Left_Opnd => Param_Level, | |
f15731c4 | 509 | Right_Opnd => Type_Level), |
510 | Reason => PE_Accessibility_Check_Failed)); | |
ee6ba406 | 511 | |
512 | Analyze_And_Resolve (N); | |
513 | end if; | |
514 | end Apply_Accessibility_Check; | |
515 | ||
0577b0b1 | 516 | -------------------------------- |
517 | -- Apply_Address_Clause_Check -- | |
518 | -------------------------------- | |
519 | ||
520 | procedure Apply_Address_Clause_Check (E : Entity_Id; N : Node_Id) is | |
521 | AC : constant Node_Id := Address_Clause (E); | |
522 | Loc : constant Source_Ptr := Sloc (AC); | |
523 | Typ : constant Entity_Id := Etype (E); | |
524 | Aexp : constant Node_Id := Expression (AC); | |
c2b56224 | 525 | |
c2b56224 | 526 | Expr : Node_Id; |
0577b0b1 | 527 | -- Address expression (not necessarily the same as Aexp, for example |
528 | -- when Aexp is a reference to a constant, in which case Expr gets | |
529 | -- reset to reference the value expression of the constant. | |
530 | ||
531 | Size_Warning_Output : Boolean := False; | |
532 | -- If we output a size warning we set this True, to stop generating | |
533 | -- what is likely to be an unuseful redundant alignment warning. | |
534 | ||
535 | procedure Compile_Time_Bad_Alignment; | |
536 | -- Post error warnings when alignment is known to be incompatible. Note | |
537 | -- that we do not go as far as inserting a raise of Program_Error since | |
538 | -- this is an erroneous case, and it may happen that we are lucky and an | |
539 | -- underaligned address turns out to be OK after all. Also this warning | |
540 | -- is suppressed if we already complained about the size. | |
541 | ||
542 | -------------------------------- | |
543 | -- Compile_Time_Bad_Alignment -- | |
544 | -------------------------------- | |
545 | ||
546 | procedure Compile_Time_Bad_Alignment is | |
547 | begin | |
548 | if not Size_Warning_Output | |
549 | and then Address_Clause_Overlay_Warnings | |
550 | then | |
551 | Error_Msg_FE | |
552 | ("?specified address for& may be inconsistent with alignment ", | |
553 | Aexp, E); | |
554 | Error_Msg_FE | |
2af58f67 | 555 | ("\?program execution may be erroneous (RM 13.3(27))", |
0577b0b1 | 556 | Aexp, E); |
83f8f0a6 | 557 | Set_Address_Warning_Posted (AC); |
0577b0b1 | 558 | end if; |
559 | end Compile_Time_Bad_Alignment; | |
c2b56224 | 560 | |
2af58f67 | 561 | -- Start of processing for Apply_Address_Clause_Check |
5c61a0ff | 562 | |
c2b56224 | 563 | begin |
0577b0b1 | 564 | -- First obtain expression from address clause |
9dfe12ae | 565 | |
0577b0b1 | 566 | Expr := Expression (AC); |
567 | ||
568 | -- The following loop digs for the real expression to use in the check | |
569 | ||
570 | loop | |
571 | -- For constant, get constant expression | |
572 | ||
573 | if Is_Entity_Name (Expr) | |
574 | and then Ekind (Entity (Expr)) = E_Constant | |
575 | then | |
576 | Expr := Constant_Value (Entity (Expr)); | |
577 | ||
578 | -- For unchecked conversion, get result to convert | |
579 | ||
580 | elsif Nkind (Expr) = N_Unchecked_Type_Conversion then | |
581 | Expr := Expression (Expr); | |
582 | ||
583 | -- For (common case) of To_Address call, get argument | |
584 | ||
585 | elsif Nkind (Expr) = N_Function_Call | |
586 | and then Is_Entity_Name (Name (Expr)) | |
587 | and then Is_RTE (Entity (Name (Expr)), RE_To_Address) | |
588 | then | |
589 | Expr := First (Parameter_Associations (Expr)); | |
590 | ||
591 | if Nkind (Expr) = N_Parameter_Association then | |
592 | Expr := Explicit_Actual_Parameter (Expr); | |
593 | end if; | |
594 | ||
595 | -- We finally have the real expression | |
596 | ||
597 | else | |
598 | exit; | |
599 | end if; | |
600 | end loop; | |
601 | ||
602 | -- Output a warning if we have the situation of | |
603 | ||
604 | -- for X'Address use Y'Address | |
605 | ||
606 | -- and X and Y both have known object sizes, and Y is smaller than X | |
607 | ||
608 | if Nkind (Expr) = N_Attribute_Reference | |
609 | and then Attribute_Name (Expr) = Name_Address | |
610 | and then Is_Entity_Name (Prefix (Expr)) | |
9dfe12ae | 611 | then |
0577b0b1 | 612 | declare |
613 | Exp_Ent : constant Entity_Id := Entity (Prefix (Expr)); | |
614 | Obj_Size : Uint := No_Uint; | |
615 | Exp_Size : Uint := No_Uint; | |
616 | ||
617 | begin | |
618 | if Known_Esize (E) then | |
619 | Obj_Size := Esize (E); | |
620 | elsif Known_Esize (Etype (E)) then | |
621 | Obj_Size := Esize (Etype (E)); | |
622 | end if; | |
623 | ||
624 | if Known_Esize (Exp_Ent) then | |
625 | Exp_Size := Esize (Exp_Ent); | |
626 | elsif Known_Esize (Etype (Exp_Ent)) then | |
627 | Exp_Size := Esize (Etype (Exp_Ent)); | |
628 | end if; | |
629 | ||
630 | if Obj_Size /= No_Uint | |
631 | and then Exp_Size /= No_Uint | |
632 | and then Obj_Size > Exp_Size | |
ce7498d3 | 633 | and then not Has_Warnings_Off (E) |
0577b0b1 | 634 | then |
635 | if Address_Clause_Overlay_Warnings then | |
636 | Error_Msg_FE | |
637 | ("?& overlays smaller object", Aexp, E); | |
638 | Error_Msg_FE | |
639 | ("\?program execution may be erroneous", Aexp, E); | |
640 | Size_Warning_Output := True; | |
83f8f0a6 | 641 | Set_Address_Warning_Posted (AC); |
0577b0b1 | 642 | end if; |
643 | end if; | |
644 | end; | |
c2b56224 | 645 | end if; |
646 | ||
0577b0b1 | 647 | -- See if alignment check needed. Note that we never need a check if the |
648 | -- maximum alignment is one, since the check will always succeed. | |
c2b56224 | 649 | |
0577b0b1 | 650 | -- Note: we do not check for checks suppressed here, since that check |
2af58f67 | 651 | -- was done in Sem_Ch13 when the address clause was processed. We are |
0577b0b1 | 652 | -- only called if checks were not suppressed. The reason for this is |
653 | -- that we have to delay the call to Apply_Alignment_Check till freeze | |
654 | -- time (so that all types etc are elaborated), but we have to check | |
655 | -- the status of check suppressing at the point of the address clause. | |
c2b56224 | 656 | |
0577b0b1 | 657 | if No (AC) |
658 | or else not Check_Address_Alignment (AC) | |
659 | or else Maximum_Alignment = 1 | |
c2b56224 | 660 | then |
0577b0b1 | 661 | return; |
c2b56224 | 662 | end if; |
663 | ||
0577b0b1 | 664 | -- See if we know that Expr is a bad alignment at compile time |
c2b56224 | 665 | |
666 | if Compile_Time_Known_Value (Expr) | |
f2a06be9 | 667 | and then (Known_Alignment (E) or else Known_Alignment (Typ)) |
c2b56224 | 668 | then |
f2a06be9 | 669 | declare |
670 | AL : Uint := Alignment (Typ); | |
671 | ||
672 | begin | |
673 | -- The object alignment might be more restrictive than the | |
674 | -- type alignment. | |
675 | ||
676 | if Known_Alignment (E) then | |
677 | AL := Alignment (E); | |
678 | end if; | |
679 | ||
680 | if Expr_Value (Expr) mod AL /= 0 then | |
0577b0b1 | 681 | Compile_Time_Bad_Alignment; |
682 | else | |
683 | return; | |
f2a06be9 | 684 | end if; |
685 | end; | |
c2b56224 | 686 | |
0577b0b1 | 687 | -- If the expression has the form X'Address, then we can find out if |
688 | -- the object X has an alignment that is compatible with the object E. | |
c2b56224 | 689 | |
0577b0b1 | 690 | elsif Nkind (Expr) = N_Attribute_Reference |
691 | and then Attribute_Name (Expr) = Name_Address | |
692 | then | |
693 | declare | |
694 | AR : constant Alignment_Result := | |
695 | Has_Compatible_Alignment (E, Prefix (Expr)); | |
696 | begin | |
697 | if AR = Known_Compatible then | |
698 | return; | |
699 | elsif AR = Known_Incompatible then | |
700 | Compile_Time_Bad_Alignment; | |
701 | end if; | |
702 | end; | |
703 | end if; | |
c2b56224 | 704 | |
0577b0b1 | 705 | -- Here we do not know if the value is acceptable. Stricly we don't have |
706 | -- to do anything, since if the alignment is bad, we have an erroneous | |
707 | -- program. However we are allowed to check for erroneous conditions and | |
708 | -- we decide to do this by default if the check is not suppressed. | |
709 | ||
710 | -- However, don't do the check if elaboration code is unwanted | |
711 | ||
712 | if Restriction_Active (No_Elaboration_Code) then | |
713 | return; | |
714 | ||
715 | -- Generate a check to raise PE if alignment may be inappropriate | |
716 | ||
717 | else | |
718 | -- If the original expression is a non-static constant, use the | |
719 | -- name of the constant itself rather than duplicating its | |
00c403ee | 720 | -- defining expression, which was extracted above. |
0577b0b1 | 721 | |
00c403ee | 722 | -- Note: Expr is empty if the address-clause is applied to in-mode |
723 | -- actuals (allowed by 13.1(22)). | |
724 | ||
725 | if not Present (Expr) | |
726 | or else | |
727 | (Is_Entity_Name (Expression (AC)) | |
728 | and then Ekind (Entity (Expression (AC))) = E_Constant | |
729 | and then Nkind (Parent (Entity (Expression (AC)))) | |
730 | = N_Object_Declaration) | |
0577b0b1 | 731 | then |
732 | Expr := New_Copy_Tree (Expression (AC)); | |
733 | else | |
734 | Remove_Side_Effects (Expr); | |
c2b56224 | 735 | end if; |
c2b56224 | 736 | |
0577b0b1 | 737 | Insert_After_And_Analyze (N, |
738 | Make_Raise_Program_Error (Loc, | |
739 | Condition => | |
740 | Make_Op_Ne (Loc, | |
741 | Left_Opnd => | |
742 | Make_Op_Mod (Loc, | |
743 | Left_Opnd => | |
744 | Unchecked_Convert_To | |
745 | (RTE (RE_Integer_Address), Expr), | |
746 | Right_Opnd => | |
747 | Make_Attribute_Reference (Loc, | |
748 | Prefix => New_Occurrence_Of (E, Loc), | |
749 | Attribute_Name => Name_Alignment)), | |
750 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
751 | Reason => PE_Misaligned_Address_Value), | |
752 | Suppress => All_Checks); | |
753 | return; | |
754 | end if; | |
9dfe12ae | 755 | |
756 | exception | |
0577b0b1 | 757 | -- If we have some missing run time component in configurable run time |
758 | -- mode then just skip the check (it is not required in any case). | |
759 | ||
9dfe12ae | 760 | when RE_Not_Available => |
761 | return; | |
0577b0b1 | 762 | end Apply_Address_Clause_Check; |
c2b56224 | 763 | |
ee6ba406 | 764 | ------------------------------------- |
765 | -- Apply_Arithmetic_Overflow_Check -- | |
766 | ------------------------------------- | |
767 | ||
768 | -- This routine is called only if the type is an integer type, and | |
769 | -- a software arithmetic overflow check must be performed for op | |
770 | -- (add, subtract, multiply). The check is performed only if | |
771 | -- Software_Overflow_Checking is enabled and Do_Overflow_Check | |
772 | -- is set. In this case we expand the operation into a more complex | |
773 | -- sequence of tests that ensures that overflow is properly caught. | |
774 | ||
775 | procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is | |
776 | Loc : constant Source_Ptr := Sloc (N); | |
777 | Typ : constant Entity_Id := Etype (N); | |
778 | Rtyp : constant Entity_Id := Root_Type (Typ); | |
779 | Siz : constant Int := UI_To_Int (Esize (Rtyp)); | |
780 | Dsiz : constant Int := Siz * 2; | |
781 | Opnod : Node_Id; | |
782 | Ctyp : Entity_Id; | |
783 | Opnd : Node_Id; | |
784 | Cent : RE_Id; | |
ee6ba406 | 785 | |
786 | begin | |
9dfe12ae | 787 | -- Skip this if overflow checks are done in back end, or the overflow |
788 | -- flag is not set anyway, or we are not doing code expansion. | |
00c403ee | 789 | -- Special case CLI target, where arithmetic overflow checks can be |
790 | -- performed for integer and long_integer | |
9dfe12ae | 791 | |
f15731c4 | 792 | if Backend_Overflow_Checks_On_Target |
00c403ee | 793 | or else (VM_Target = CLI_Target and then Siz >= Standard_Integer_Size) |
284faf8b | 794 | or else not Do_Overflow_Check (N) |
795 | or else not Expander_Active | |
ee6ba406 | 796 | then |
797 | return; | |
798 | end if; | |
799 | ||
9dfe12ae | 800 | -- Otherwise, we generate the full general code for front end overflow |
801 | -- detection, which works by doing arithmetic in a larger type: | |
ee6ba406 | 802 | |
803 | -- x op y | |
804 | ||
805 | -- is expanded into | |
806 | ||
807 | -- Typ (Checktyp (x) op Checktyp (y)); | |
808 | ||
809 | -- where Typ is the type of the original expression, and Checktyp is | |
810 | -- an integer type of sufficient length to hold the largest possible | |
811 | -- result. | |
812 | ||
813 | -- In the case where check type exceeds the size of Long_Long_Integer, | |
814 | -- we use a different approach, expanding to: | |
815 | ||
816 | -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y))) | |
817 | ||
818 | -- where xxx is Add, Multiply or Subtract as appropriate | |
819 | ||
820 | -- Find check type if one exists | |
821 | ||
822 | if Dsiz <= Standard_Integer_Size then | |
823 | Ctyp := Standard_Integer; | |
824 | ||
825 | elsif Dsiz <= Standard_Long_Long_Integer_Size then | |
826 | Ctyp := Standard_Long_Long_Integer; | |
827 | ||
828 | -- No check type exists, use runtime call | |
829 | ||
830 | else | |
831 | if Nkind (N) = N_Op_Add then | |
832 | Cent := RE_Add_With_Ovflo_Check; | |
833 | ||
834 | elsif Nkind (N) = N_Op_Multiply then | |
835 | Cent := RE_Multiply_With_Ovflo_Check; | |
836 | ||
837 | else | |
838 | pragma Assert (Nkind (N) = N_Op_Subtract); | |
839 | Cent := RE_Subtract_With_Ovflo_Check; | |
840 | end if; | |
841 | ||
842 | Rewrite (N, | |
843 | OK_Convert_To (Typ, | |
844 | Make_Function_Call (Loc, | |
845 | Name => New_Reference_To (RTE (Cent), Loc), | |
846 | Parameter_Associations => New_List ( | |
847 | OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)), | |
848 | OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N)))))); | |
849 | ||
850 | Analyze_And_Resolve (N, Typ); | |
851 | return; | |
852 | end if; | |
853 | ||
854 | -- If we fall through, we have the case where we do the arithmetic in | |
855 | -- the next higher type and get the check by conversion. In these cases | |
856 | -- Ctyp is set to the type to be used as the check type. | |
857 | ||
858 | Opnod := Relocate_Node (N); | |
859 | ||
860 | Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod)); | |
861 | ||
862 | Analyze (Opnd); | |
863 | Set_Etype (Opnd, Ctyp); | |
864 | Set_Analyzed (Opnd, True); | |
865 | Set_Left_Opnd (Opnod, Opnd); | |
866 | ||
867 | Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod)); | |
868 | ||
869 | Analyze (Opnd); | |
870 | Set_Etype (Opnd, Ctyp); | |
871 | Set_Analyzed (Opnd, True); | |
872 | Set_Right_Opnd (Opnod, Opnd); | |
873 | ||
feff2f05 | 874 | -- The type of the operation changes to the base type of the check type, |
875 | -- and we reset the overflow check indication, since clearly no overflow | |
876 | -- is possible now that we are using a double length type. We also set | |
877 | -- the Analyzed flag to avoid a recursive attempt to expand the node. | |
ee6ba406 | 878 | |
879 | Set_Etype (Opnod, Base_Type (Ctyp)); | |
880 | Set_Do_Overflow_Check (Opnod, False); | |
881 | Set_Analyzed (Opnod, True); | |
882 | ||
883 | -- Now build the outer conversion | |
884 | ||
885 | Opnd := OK_Convert_To (Typ, Opnod); | |
ee6ba406 | 886 | Analyze (Opnd); |
887 | Set_Etype (Opnd, Typ); | |
ee6ba406 | 888 | |
feff2f05 | 889 | -- In the discrete type case, we directly generate the range check for |
890 | -- the outer operand. This range check will implement the required | |
9dfe12ae | 891 | -- overflow check. |
892 | ||
893 | if Is_Discrete_Type (Typ) then | |
894 | Rewrite (N, Opnd); | |
895 | Generate_Range_Check (Expression (N), Typ, CE_Overflow_Check_Failed); | |
896 | ||
897 | -- For other types, we enable overflow checking on the conversion, | |
898 | -- after setting the node as analyzed to prevent recursive attempts | |
899 | -- to expand the conversion node. | |
900 | ||
901 | else | |
902 | Set_Analyzed (Opnd, True); | |
903 | Enable_Overflow_Check (Opnd); | |
904 | Rewrite (N, Opnd); | |
905 | end if; | |
906 | ||
907 | exception | |
908 | when RE_Not_Available => | |
909 | return; | |
ee6ba406 | 910 | end Apply_Arithmetic_Overflow_Check; |
911 | ||
ee6ba406 | 912 | ---------------------------- |
913 | -- Apply_Constraint_Check -- | |
914 | ---------------------------- | |
915 | ||
916 | procedure Apply_Constraint_Check | |
917 | (N : Node_Id; | |
918 | Typ : Entity_Id; | |
919 | No_Sliding : Boolean := False) | |
920 | is | |
921 | Desig_Typ : Entity_Id; | |
922 | ||
923 | begin | |
924 | if Inside_A_Generic then | |
925 | return; | |
926 | ||
927 | elsif Is_Scalar_Type (Typ) then | |
928 | Apply_Scalar_Range_Check (N, Typ); | |
929 | ||
930 | elsif Is_Array_Type (Typ) then | |
931 | ||
05fcfafb | 932 | -- A useful optimization: an aggregate with only an others clause |
5f260d20 | 933 | -- always has the right bounds. |
934 | ||
935 | if Nkind (N) = N_Aggregate | |
936 | and then No (Expressions (N)) | |
937 | and then Nkind | |
938 | (First (Choices (First (Component_Associations (N))))) | |
939 | = N_Others_Choice | |
940 | then | |
941 | return; | |
942 | end if; | |
943 | ||
ee6ba406 | 944 | if Is_Constrained (Typ) then |
945 | Apply_Length_Check (N, Typ); | |
946 | ||
947 | if No_Sliding then | |
948 | Apply_Range_Check (N, Typ); | |
949 | end if; | |
950 | else | |
951 | Apply_Range_Check (N, Typ); | |
952 | end if; | |
953 | ||
954 | elsif (Is_Record_Type (Typ) | |
955 | or else Is_Private_Type (Typ)) | |
956 | and then Has_Discriminants (Base_Type (Typ)) | |
957 | and then Is_Constrained (Typ) | |
958 | then | |
959 | Apply_Discriminant_Check (N, Typ); | |
960 | ||
961 | elsif Is_Access_Type (Typ) then | |
962 | ||
963 | Desig_Typ := Designated_Type (Typ); | |
964 | ||
965 | -- No checks necessary if expression statically null | |
966 | ||
2af58f67 | 967 | if Known_Null (N) then |
00c403ee | 968 | if Can_Never_Be_Null (Typ) then |
969 | Install_Null_Excluding_Check (N); | |
970 | end if; | |
ee6ba406 | 971 | |
972 | -- No sliding possible on access to arrays | |
973 | ||
974 | elsif Is_Array_Type (Desig_Typ) then | |
975 | if Is_Constrained (Desig_Typ) then | |
976 | Apply_Length_Check (N, Typ); | |
977 | end if; | |
978 | ||
979 | Apply_Range_Check (N, Typ); | |
980 | ||
981 | elsif Has_Discriminants (Base_Type (Desig_Typ)) | |
982 | and then Is_Constrained (Desig_Typ) | |
983 | then | |
984 | Apply_Discriminant_Check (N, Typ); | |
985 | end if; | |
fa7497e8 | 986 | |
00c403ee | 987 | -- Apply the the 2005 Null_Excluding check. Note that we do not apply |
988 | -- this check if the constraint node is illegal, as shown by having | |
989 | -- an error posted. This additional guard prevents cascaded errors | |
990 | -- and compiler aborts on illegal programs involving Ada 2005 checks. | |
991 | ||
fa7497e8 | 992 | if Can_Never_Be_Null (Typ) |
993 | and then not Can_Never_Be_Null (Etype (N)) | |
00c403ee | 994 | and then not Error_Posted (N) |
fa7497e8 | 995 | then |
996 | Install_Null_Excluding_Check (N); | |
997 | end if; | |
ee6ba406 | 998 | end if; |
999 | end Apply_Constraint_Check; | |
1000 | ||
1001 | ------------------------------ | |
1002 | -- Apply_Discriminant_Check -- | |
1003 | ------------------------------ | |
1004 | ||
1005 | procedure Apply_Discriminant_Check | |
1006 | (N : Node_Id; | |
1007 | Typ : Entity_Id; | |
1008 | Lhs : Node_Id := Empty) | |
1009 | is | |
1010 | Loc : constant Source_Ptr := Sloc (N); | |
1011 | Do_Access : constant Boolean := Is_Access_Type (Typ); | |
1012 | S_Typ : Entity_Id := Etype (N); | |
1013 | Cond : Node_Id; | |
1014 | T_Typ : Entity_Id; | |
1015 | ||
1016 | function Is_Aliased_Unconstrained_Component return Boolean; | |
1017 | -- It is possible for an aliased component to have a nominal | |
1018 | -- unconstrained subtype (through instantiation). If this is a | |
1019 | -- discriminated component assigned in the expansion of an aggregate | |
1020 | -- in an initialization, the check must be suppressed. This unusual | |
2af58f67 | 1021 | -- situation requires a predicate of its own. |
ee6ba406 | 1022 | |
1023 | ---------------------------------------- | |
1024 | -- Is_Aliased_Unconstrained_Component -- | |
1025 | ---------------------------------------- | |
1026 | ||
1027 | function Is_Aliased_Unconstrained_Component return Boolean is | |
1028 | Comp : Entity_Id; | |
1029 | Pref : Node_Id; | |
1030 | ||
1031 | begin | |
1032 | if Nkind (Lhs) /= N_Selected_Component then | |
1033 | return False; | |
1034 | else | |
1035 | Comp := Entity (Selector_Name (Lhs)); | |
1036 | Pref := Prefix (Lhs); | |
1037 | end if; | |
1038 | ||
1039 | if Ekind (Comp) /= E_Component | |
1040 | or else not Is_Aliased (Comp) | |
1041 | then | |
1042 | return False; | |
1043 | end if; | |
1044 | ||
1045 | return not Comes_From_Source (Pref) | |
1046 | and then In_Instance | |
1047 | and then not Is_Constrained (Etype (Comp)); | |
1048 | end Is_Aliased_Unconstrained_Component; | |
1049 | ||
1050 | -- Start of processing for Apply_Discriminant_Check | |
1051 | ||
1052 | begin | |
1053 | if Do_Access then | |
1054 | T_Typ := Designated_Type (Typ); | |
1055 | else | |
1056 | T_Typ := Typ; | |
1057 | end if; | |
1058 | ||
1059 | -- Nothing to do if discriminant checks are suppressed or else no code | |
1060 | -- is to be generated | |
1061 | ||
1062 | if not Expander_Active | |
1063 | or else Discriminant_Checks_Suppressed (T_Typ) | |
1064 | then | |
1065 | return; | |
1066 | end if; | |
1067 | ||
feff2f05 | 1068 | -- No discriminant checks necessary for an access when expression is |
1069 | -- statically Null. This is not only an optimization, it is fundamental | |
1070 | -- because otherwise discriminant checks may be generated in init procs | |
1071 | -- for types containing an access to a not-yet-frozen record, causing a | |
1072 | -- deadly forward reference. | |
ee6ba406 | 1073 | |
feff2f05 | 1074 | -- Also, if the expression is of an access type whose designated type is |
1075 | -- incomplete, then the access value must be null and we suppress the | |
1076 | -- check. | |
ee6ba406 | 1077 | |
2af58f67 | 1078 | if Known_Null (N) then |
ee6ba406 | 1079 | return; |
1080 | ||
1081 | elsif Is_Access_Type (S_Typ) then | |
1082 | S_Typ := Designated_Type (S_Typ); | |
1083 | ||
1084 | if Ekind (S_Typ) = E_Incomplete_Type then | |
1085 | return; | |
1086 | end if; | |
1087 | end if; | |
1088 | ||
0577b0b1 | 1089 | -- If an assignment target is present, then we need to generate the |
1090 | -- actual subtype if the target is a parameter or aliased object with | |
1091 | -- an unconstrained nominal subtype. | |
1092 | ||
1093 | -- Ada 2005 (AI-363): For Ada 2005, we limit the building of the actual | |
1094 | -- subtype to the parameter and dereference cases, since other aliased | |
1095 | -- objects are unconstrained (unless the nominal subtype is explicitly | |
1096 | -- constrained). (But we also need to test for renamings???) | |
ee6ba406 | 1097 | |
1098 | if Present (Lhs) | |
1099 | and then (Present (Param_Entity (Lhs)) | |
0577b0b1 | 1100 | or else (Ada_Version < Ada_05 |
1101 | and then not Is_Constrained (T_Typ) | |
ee6ba406 | 1102 | and then Is_Aliased_View (Lhs) |
0577b0b1 | 1103 | and then not Is_Aliased_Unconstrained_Component) |
1104 | or else (Ada_Version >= Ada_05 | |
1105 | and then not Is_Constrained (T_Typ) | |
1106 | and then Nkind (Lhs) = N_Explicit_Dereference | |
1107 | and then Nkind (Original_Node (Lhs)) /= | |
1108 | N_Function_Call)) | |
ee6ba406 | 1109 | then |
1110 | T_Typ := Get_Actual_Subtype (Lhs); | |
1111 | end if; | |
1112 | ||
feff2f05 | 1113 | -- Nothing to do if the type is unconstrained (this is the case where |
1114 | -- the actual subtype in the RM sense of N is unconstrained and no check | |
1115 | -- is required). | |
ee6ba406 | 1116 | |
1117 | if not Is_Constrained (T_Typ) then | |
1118 | return; | |
05fcfafb | 1119 | |
1120 | -- Ada 2005: nothing to do if the type is one for which there is a | |
1121 | -- partial view that is constrained. | |
1122 | ||
1123 | elsif Ada_Version >= Ada_05 | |
1124 | and then Has_Constrained_Partial_View (Base_Type (T_Typ)) | |
1125 | then | |
1126 | return; | |
ee6ba406 | 1127 | end if; |
1128 | ||
00f91aef | 1129 | -- Nothing to do if the type is an Unchecked_Union |
1130 | ||
1131 | if Is_Unchecked_Union (Base_Type (T_Typ)) then | |
1132 | return; | |
1133 | end if; | |
1134 | ||
feff2f05 | 1135 | -- Suppress checks if the subtypes are the same. the check must be |
1136 | -- preserved in an assignment to a formal, because the constraint is | |
1137 | -- given by the actual. | |
ee6ba406 | 1138 | |
1139 | if Nkind (Original_Node (N)) /= N_Allocator | |
1140 | and then (No (Lhs) | |
1141 | or else not Is_Entity_Name (Lhs) | |
9dfe12ae | 1142 | or else No (Param_Entity (Lhs))) |
ee6ba406 | 1143 | then |
1144 | if (Etype (N) = Typ | |
1145 | or else (Do_Access and then Designated_Type (Typ) = S_Typ)) | |
1146 | and then not Is_Aliased_View (Lhs) | |
1147 | then | |
1148 | return; | |
1149 | end if; | |
1150 | ||
feff2f05 | 1151 | -- We can also eliminate checks on allocators with a subtype mark that |
1152 | -- coincides with the context type. The context type may be a subtype | |
1153 | -- without a constraint (common case, a generic actual). | |
ee6ba406 | 1154 | |
1155 | elsif Nkind (Original_Node (N)) = N_Allocator | |
1156 | and then Is_Entity_Name (Expression (Original_Node (N))) | |
1157 | then | |
1158 | declare | |
9dfe12ae | 1159 | Alloc_Typ : constant Entity_Id := |
1160 | Entity (Expression (Original_Node (N))); | |
ee6ba406 | 1161 | |
1162 | begin | |
1163 | if Alloc_Typ = T_Typ | |
1164 | or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration | |
1165 | and then Is_Entity_Name ( | |
1166 | Subtype_Indication (Parent (T_Typ))) | |
1167 | and then Alloc_Typ = Base_Type (T_Typ)) | |
1168 | ||
1169 | then | |
1170 | return; | |
1171 | end if; | |
1172 | end; | |
1173 | end if; | |
1174 | ||
feff2f05 | 1175 | -- See if we have a case where the types are both constrained, and all |
1176 | -- the constraints are constants. In this case, we can do the check | |
1177 | -- successfully at compile time. | |
ee6ba406 | 1178 | |
9dfe12ae | 1179 | -- We skip this check for the case where the node is a rewritten` |
ee6ba406 | 1180 | -- allocator, because it already carries the context subtype, and |
1181 | -- extracting the discriminants from the aggregate is messy. | |
1182 | ||
1183 | if Is_Constrained (S_Typ) | |
1184 | and then Nkind (Original_Node (N)) /= N_Allocator | |
1185 | then | |
1186 | declare | |
1187 | DconT : Elmt_Id; | |
1188 | Discr : Entity_Id; | |
1189 | DconS : Elmt_Id; | |
1190 | ItemS : Node_Id; | |
1191 | ItemT : Node_Id; | |
1192 | ||
1193 | begin | |
1194 | -- S_Typ may not have discriminants in the case where it is a | |
feff2f05 | 1195 | -- private type completed by a default discriminated type. In that |
1196 | -- case, we need to get the constraints from the underlying_type. | |
1197 | -- If the underlying type is unconstrained (i.e. has no default | |
1198 | -- discriminants) no check is needed. | |
ee6ba406 | 1199 | |
1200 | if Has_Discriminants (S_Typ) then | |
1201 | Discr := First_Discriminant (S_Typ); | |
1202 | DconS := First_Elmt (Discriminant_Constraint (S_Typ)); | |
1203 | ||
1204 | else | |
1205 | Discr := First_Discriminant (Underlying_Type (S_Typ)); | |
1206 | DconS := | |
1207 | First_Elmt | |
1208 | (Discriminant_Constraint (Underlying_Type (S_Typ))); | |
1209 | ||
1210 | if No (DconS) then | |
1211 | return; | |
1212 | end if; | |
fccb5da7 | 1213 | |
1214 | -- A further optimization: if T_Typ is derived from S_Typ | |
1215 | -- without imposing a constraint, no check is needed. | |
1216 | ||
1217 | if Nkind (Original_Node (Parent (T_Typ))) = | |
1218 | N_Full_Type_Declaration | |
1219 | then | |
1220 | declare | |
5c61a0ff | 1221 | Type_Def : constant Node_Id := |
fccb5da7 | 1222 | Type_Definition |
1223 | (Original_Node (Parent (T_Typ))); | |
1224 | begin | |
1225 | if Nkind (Type_Def) = N_Derived_Type_Definition | |
1226 | and then Is_Entity_Name (Subtype_Indication (Type_Def)) | |
1227 | and then Entity (Subtype_Indication (Type_Def)) = S_Typ | |
1228 | then | |
1229 | return; | |
1230 | end if; | |
1231 | end; | |
1232 | end if; | |
ee6ba406 | 1233 | end if; |
1234 | ||
1235 | DconT := First_Elmt (Discriminant_Constraint (T_Typ)); | |
1236 | ||
1237 | while Present (Discr) loop | |
1238 | ItemS := Node (DconS); | |
1239 | ItemT := Node (DconT); | |
1240 | ||
00c403ee | 1241 | -- For a discriminated component type constrained by the |
1242 | -- current instance of an enclosing type, there is no | |
1243 | -- applicable discriminant check. | |
1244 | ||
1245 | if Nkind (ItemT) = N_Attribute_Reference | |
1246 | and then Is_Access_Type (Etype (ItemT)) | |
1247 | and then Is_Entity_Name (Prefix (ItemT)) | |
1248 | and then Is_Type (Entity (Prefix (ItemT))) | |
1249 | then | |
1250 | return; | |
1251 | end if; | |
1252 | ||
cc60bd16 | 1253 | -- If the expressions for the discriminants are identical |
1254 | -- and it is side-effect free (for now just an entity), | |
1255 | -- this may be a shared constraint, e.g. from a subtype | |
1256 | -- without a constraint introduced as a generic actual. | |
1257 | -- Examine other discriminants if any. | |
1258 | ||
1259 | if ItemS = ItemT | |
1260 | and then Is_Entity_Name (ItemS) | |
1261 | then | |
1262 | null; | |
1263 | ||
1264 | elsif not Is_OK_Static_Expression (ItemS) | |
1265 | or else not Is_OK_Static_Expression (ItemT) | |
1266 | then | |
1267 | exit; | |
ee6ba406 | 1268 | |
cc60bd16 | 1269 | elsif Expr_Value (ItemS) /= Expr_Value (ItemT) then |
ee6ba406 | 1270 | if Do_Access then -- needs run-time check. |
1271 | exit; | |
1272 | else | |
1273 | Apply_Compile_Time_Constraint_Error | |
f15731c4 | 1274 | (N, "incorrect value for discriminant&?", |
1275 | CE_Discriminant_Check_Failed, Ent => Discr); | |
ee6ba406 | 1276 | return; |
1277 | end if; | |
1278 | end if; | |
1279 | ||
1280 | Next_Elmt (DconS); | |
1281 | Next_Elmt (DconT); | |
1282 | Next_Discriminant (Discr); | |
1283 | end loop; | |
1284 | ||
1285 | if No (Discr) then | |
1286 | return; | |
1287 | end if; | |
1288 | end; | |
1289 | end if; | |
1290 | ||
1291 | -- Here we need a discriminant check. First build the expression | |
1292 | -- for the comparisons of the discriminants: | |
1293 | ||
1294 | -- (n.disc1 /= typ.disc1) or else | |
1295 | -- (n.disc2 /= typ.disc2) or else | |
1296 | -- ... | |
1297 | -- (n.discn /= typ.discn) | |
1298 | ||
1299 | Cond := Build_Discriminant_Checks (N, T_Typ); | |
1300 | ||
1301 | -- If Lhs is set and is a parameter, then the condition is | |
1302 | -- guarded by: lhs'constrained and then (condition built above) | |
1303 | ||
1304 | if Present (Param_Entity (Lhs)) then | |
1305 | Cond := | |
1306 | Make_And_Then (Loc, | |
1307 | Left_Opnd => | |
1308 | Make_Attribute_Reference (Loc, | |
1309 | Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc), | |
1310 | Attribute_Name => Name_Constrained), | |
1311 | Right_Opnd => Cond); | |
1312 | end if; | |
1313 | ||
1314 | if Do_Access then | |
1315 | Cond := Guard_Access (Cond, Loc, N); | |
1316 | end if; | |
1317 | ||
1318 | Insert_Action (N, | |
f15731c4 | 1319 | Make_Raise_Constraint_Error (Loc, |
1320 | Condition => Cond, | |
1321 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 1322 | end Apply_Discriminant_Check; |
1323 | ||
1324 | ------------------------ | |
1325 | -- Apply_Divide_Check -- | |
1326 | ------------------------ | |
1327 | ||
1328 | procedure Apply_Divide_Check (N : Node_Id) is | |
1329 | Loc : constant Source_Ptr := Sloc (N); | |
1330 | Typ : constant Entity_Id := Etype (N); | |
1331 | Left : constant Node_Id := Left_Opnd (N); | |
1332 | Right : constant Node_Id := Right_Opnd (N); | |
1333 | ||
1334 | LLB : Uint; | |
1335 | Llo : Uint; | |
1336 | Lhi : Uint; | |
1337 | LOK : Boolean; | |
1338 | Rlo : Uint; | |
1339 | Rhi : Uint; | |
96da3284 | 1340 | ROK : Boolean; |
1341 | ||
1342 | pragma Warnings (Off, Lhi); | |
1343 | -- Don't actually use this value | |
ee6ba406 | 1344 | |
1345 | begin | |
1346 | if Expander_Active | |
13dbf220 | 1347 | and then not Backend_Divide_Checks_On_Target |
1348 | and then Check_Needed (Right, Division_Check) | |
ee6ba406 | 1349 | then |
1350 | Determine_Range (Right, ROK, Rlo, Rhi); | |
1351 | ||
1352 | -- See if division by zero possible, and if so generate test. This | |
1353 | -- part of the test is not controlled by the -gnato switch. | |
1354 | ||
1355 | if Do_Division_Check (N) then | |
ee6ba406 | 1356 | if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then |
1357 | Insert_Action (N, | |
1358 | Make_Raise_Constraint_Error (Loc, | |
1359 | Condition => | |
1360 | Make_Op_Eq (Loc, | |
0577b0b1 | 1361 | Left_Opnd => Duplicate_Subexpr_Move_Checks (Right), |
f15731c4 | 1362 | Right_Opnd => Make_Integer_Literal (Loc, 0)), |
1363 | Reason => CE_Divide_By_Zero)); | |
ee6ba406 | 1364 | end if; |
1365 | end if; | |
1366 | ||
1367 | -- Test for extremely annoying case of xxx'First divided by -1 | |
1368 | ||
1369 | if Do_Overflow_Check (N) then | |
ee6ba406 | 1370 | if Nkind (N) = N_Op_Divide |
1371 | and then Is_Signed_Integer_Type (Typ) | |
1372 | then | |
1373 | Determine_Range (Left, LOK, Llo, Lhi); | |
1374 | LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ))); | |
1375 | ||
1376 | if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) | |
1377 | and then | |
1378 | ((not LOK) or else (Llo = LLB)) | |
1379 | then | |
1380 | Insert_Action (N, | |
1381 | Make_Raise_Constraint_Error (Loc, | |
1382 | Condition => | |
1383 | Make_And_Then (Loc, | |
1384 | ||
1385 | Make_Op_Eq (Loc, | |
9dfe12ae | 1386 | Left_Opnd => |
1387 | Duplicate_Subexpr_Move_Checks (Left), | |
ee6ba406 | 1388 | Right_Opnd => Make_Integer_Literal (Loc, LLB)), |
1389 | ||
1390 | Make_Op_Eq (Loc, | |
9dfe12ae | 1391 | Left_Opnd => |
1392 | Duplicate_Subexpr (Right), | |
ee6ba406 | 1393 | Right_Opnd => |
f15731c4 | 1394 | Make_Integer_Literal (Loc, -1))), |
1395 | Reason => CE_Overflow_Check_Failed)); | |
ee6ba406 | 1396 | end if; |
1397 | end if; | |
1398 | end if; | |
1399 | end if; | |
1400 | end Apply_Divide_Check; | |
1401 | ||
5329ca64 | 1402 | ---------------------------------- |
1403 | -- Apply_Float_Conversion_Check -- | |
1404 | ---------------------------------- | |
1405 | ||
feff2f05 | 1406 | -- Let F and I be the source and target types of the conversion. The RM |
1407 | -- specifies that a floating-point value X is rounded to the nearest | |
1408 | -- integer, with halfway cases being rounded away from zero. The rounded | |
1409 | -- value of X is checked against I'Range. | |
1410 | ||
1411 | -- The catch in the above paragraph is that there is no good way to know | |
1412 | -- whether the round-to-integer operation resulted in overflow. A remedy is | |
1413 | -- to perform a range check in the floating-point domain instead, however: | |
5329ca64 | 1414 | |
5329ca64 | 1415 | -- (1) The bounds may not be known at compile time |
2af58f67 | 1416 | -- (2) The check must take into account rounding or truncation. |
5329ca64 | 1417 | -- (3) The range of type I may not be exactly representable in F. |
2af58f67 | 1418 | -- (4) For the rounding case, The end-points I'First - 0.5 and |
1419 | -- I'Last + 0.5 may or may not be in range, depending on the | |
1420 | -- sign of I'First and I'Last. | |
5329ca64 | 1421 | -- (5) X may be a NaN, which will fail any comparison |
1422 | ||
2af58f67 | 1423 | -- The following steps correctly convert X with rounding: |
feff2f05 | 1424 | |
5329ca64 | 1425 | -- (1) If either I'First or I'Last is not known at compile time, use |
1426 | -- I'Base instead of I in the next three steps and perform a | |
1427 | -- regular range check against I'Range after conversion. | |
1428 | -- (2) If I'First - 0.5 is representable in F then let Lo be that | |
1429 | -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be | |
2af58f67 | 1430 | -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First). |
1431 | -- In other words, take one of the closest floating-point numbers | |
1432 | -- (which is an integer value) to I'First, and see if it is in | |
1433 | -- range or not. | |
5329ca64 | 1434 | -- (3) If I'Last + 0.5 is representable in F then let Hi be that value |
1435 | -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be | |
2af58f67 | 1436 | -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last). |
5329ca64 | 1437 | -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo) |
1438 | -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi) | |
1439 | ||
2af58f67 | 1440 | -- For the truncating case, replace steps (2) and (3) as follows: |
1441 | -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK | |
1442 | -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let | |
1443 | -- Lo_OK be True. | |
1444 | -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK | |
1445 | -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let | |
1446 | -- Hi_OK be False | |
1447 | ||
5329ca64 | 1448 | procedure Apply_Float_Conversion_Check |
1449 | (Ck_Node : Node_Id; | |
1450 | Target_Typ : Entity_Id) | |
1451 | is | |
feff2f05 | 1452 | LB : constant Node_Id := Type_Low_Bound (Target_Typ); |
1453 | HB : constant Node_Id := Type_High_Bound (Target_Typ); | |
5329ca64 | 1454 | Loc : constant Source_Ptr := Sloc (Ck_Node); |
1455 | Expr_Type : constant Entity_Id := Base_Type (Etype (Ck_Node)); | |
feff2f05 | 1456 | Target_Base : constant Entity_Id := |
1457 | Implementation_Base_Type (Target_Typ); | |
1458 | ||
2af58f67 | 1459 | Par : constant Node_Id := Parent (Ck_Node); |
1460 | pragma Assert (Nkind (Par) = N_Type_Conversion); | |
1461 | -- Parent of check node, must be a type conversion | |
1462 | ||
1463 | Truncate : constant Boolean := Float_Truncate (Par); | |
1464 | Max_Bound : constant Uint := | |
1465 | UI_Expon | |
1466 | (Machine_Radix (Expr_Type), | |
1467 | Machine_Mantissa (Expr_Type) - 1) - 1; | |
1468 | ||
5329ca64 | 1469 | -- Largest bound, so bound plus or minus half is a machine number of F |
1470 | ||
feff2f05 | 1471 | Ifirst, Ilast : Uint; |
1472 | -- Bounds of integer type | |
1473 | ||
1474 | Lo, Hi : Ureal; | |
1475 | -- Bounds to check in floating-point domain | |
5329ca64 | 1476 | |
feff2f05 | 1477 | Lo_OK, Hi_OK : Boolean; |
1478 | -- True iff Lo resp. Hi belongs to I'Range | |
5329ca64 | 1479 | |
feff2f05 | 1480 | Lo_Chk, Hi_Chk : Node_Id; |
1481 | -- Expressions that are False iff check fails | |
1482 | ||
1483 | Reason : RT_Exception_Code; | |
5329ca64 | 1484 | |
1485 | begin | |
1486 | if not Compile_Time_Known_Value (LB) | |
1487 | or not Compile_Time_Known_Value (HB) | |
1488 | then | |
1489 | declare | |
feff2f05 | 1490 | -- First check that the value falls in the range of the base type, |
1491 | -- to prevent overflow during conversion and then perform a | |
1492 | -- regular range check against the (dynamic) bounds. | |
5329ca64 | 1493 | |
5329ca64 | 1494 | pragma Assert (Target_Base /= Target_Typ); |
5329ca64 | 1495 | |
1496 | Temp : constant Entity_Id := | |
1497 | Make_Defining_Identifier (Loc, | |
1498 | Chars => New_Internal_Name ('T')); | |
1499 | ||
1500 | begin | |
1501 | Apply_Float_Conversion_Check (Ck_Node, Target_Base); | |
1502 | Set_Etype (Temp, Target_Base); | |
1503 | ||
1504 | Insert_Action (Parent (Par), | |
1505 | Make_Object_Declaration (Loc, | |
1506 | Defining_Identifier => Temp, | |
1507 | Object_Definition => New_Occurrence_Of (Target_Typ, Loc), | |
1508 | Expression => New_Copy_Tree (Par)), | |
1509 | Suppress => All_Checks); | |
1510 | ||
1511 | Insert_Action (Par, | |
1512 | Make_Raise_Constraint_Error (Loc, | |
1513 | Condition => | |
1514 | Make_Not_In (Loc, | |
1515 | Left_Opnd => New_Occurrence_Of (Temp, Loc), | |
1516 | Right_Opnd => New_Occurrence_Of (Target_Typ, Loc)), | |
1517 | Reason => CE_Range_Check_Failed)); | |
1518 | Rewrite (Par, New_Occurrence_Of (Temp, Loc)); | |
1519 | ||
1520 | return; | |
1521 | end; | |
1522 | end if; | |
1523 | ||
1524 | -- Get the bounds of the target type | |
1525 | ||
1526 | Ifirst := Expr_Value (LB); | |
1527 | Ilast := Expr_Value (HB); | |
1528 | ||
1529 | -- Check against lower bound | |
1530 | ||
2af58f67 | 1531 | if Truncate and then Ifirst > 0 then |
1532 | Lo := Pred (Expr_Type, UR_From_Uint (Ifirst)); | |
1533 | Lo_OK := False; | |
1534 | ||
1535 | elsif Truncate then | |
1536 | Lo := Succ (Expr_Type, UR_From_Uint (Ifirst - 1)); | |
1537 | Lo_OK := True; | |
1538 | ||
1539 | elsif abs (Ifirst) < Max_Bound then | |
5329ca64 | 1540 | Lo := UR_From_Uint (Ifirst) - Ureal_Half; |
1541 | Lo_OK := (Ifirst > 0); | |
2af58f67 | 1542 | |
5329ca64 | 1543 | else |
1544 | Lo := Machine (Expr_Type, UR_From_Uint (Ifirst), Round_Even, Ck_Node); | |
1545 | Lo_OK := (Lo >= UR_From_Uint (Ifirst)); | |
1546 | end if; | |
1547 | ||
1548 | if Lo_OK then | |
1549 | ||
1550 | -- Lo_Chk := (X >= Lo) | |
1551 | ||
1552 | Lo_Chk := Make_Op_Ge (Loc, | |
1553 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1554 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
1555 | ||
1556 | else | |
1557 | -- Lo_Chk := (X > Lo) | |
1558 | ||
1559 | Lo_Chk := Make_Op_Gt (Loc, | |
1560 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1561 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
1562 | end if; | |
1563 | ||
1564 | -- Check against higher bound | |
1565 | ||
2af58f67 | 1566 | if Truncate and then Ilast < 0 then |
1567 | Hi := Succ (Expr_Type, UR_From_Uint (Ilast)); | |
1568 | Lo_OK := False; | |
1569 | ||
1570 | elsif Truncate then | |
1571 | Hi := Pred (Expr_Type, UR_From_Uint (Ilast + 1)); | |
1572 | Hi_OK := True; | |
1573 | ||
1574 | elsif abs (Ilast) < Max_Bound then | |
5329ca64 | 1575 | Hi := UR_From_Uint (Ilast) + Ureal_Half; |
1576 | Hi_OK := (Ilast < 0); | |
1577 | else | |
1578 | Hi := Machine (Expr_Type, UR_From_Uint (Ilast), Round_Even, Ck_Node); | |
1579 | Hi_OK := (Hi <= UR_From_Uint (Ilast)); | |
1580 | end if; | |
1581 | ||
1582 | if Hi_OK then | |
1583 | ||
1584 | -- Hi_Chk := (X <= Hi) | |
1585 | ||
1586 | Hi_Chk := Make_Op_Le (Loc, | |
1587 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1588 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
1589 | ||
1590 | else | |
1591 | -- Hi_Chk := (X < Hi) | |
1592 | ||
1593 | Hi_Chk := Make_Op_Lt (Loc, | |
1594 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1595 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
1596 | end if; | |
1597 | ||
feff2f05 | 1598 | -- If the bounds of the target type are the same as those of the base |
1599 | -- type, the check is an overflow check as a range check is not | |
1600 | -- performed in these cases. | |
5329ca64 | 1601 | |
1602 | if Expr_Value (Type_Low_Bound (Target_Base)) = Ifirst | |
1603 | and then Expr_Value (Type_High_Bound (Target_Base)) = Ilast | |
1604 | then | |
1605 | Reason := CE_Overflow_Check_Failed; | |
1606 | else | |
1607 | Reason := CE_Range_Check_Failed; | |
1608 | end if; | |
1609 | ||
1610 | -- Raise CE if either conditions does not hold | |
1611 | ||
1612 | Insert_Action (Ck_Node, | |
1613 | Make_Raise_Constraint_Error (Loc, | |
05fcfafb | 1614 | Condition => Make_Op_Not (Loc, Make_And_Then (Loc, Lo_Chk, Hi_Chk)), |
5329ca64 | 1615 | Reason => Reason)); |
1616 | end Apply_Float_Conversion_Check; | |
1617 | ||
ee6ba406 | 1618 | ------------------------ |
1619 | -- Apply_Length_Check -- | |
1620 | ------------------------ | |
1621 | ||
1622 | procedure Apply_Length_Check | |
1623 | (Ck_Node : Node_Id; | |
1624 | Target_Typ : Entity_Id; | |
1625 | Source_Typ : Entity_Id := Empty) | |
1626 | is | |
1627 | begin | |
1628 | Apply_Selected_Length_Checks | |
1629 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
1630 | end Apply_Length_Check; | |
1631 | ||
1632 | ----------------------- | |
1633 | -- Apply_Range_Check -- | |
1634 | ----------------------- | |
1635 | ||
1636 | procedure Apply_Range_Check | |
1637 | (Ck_Node : Node_Id; | |
1638 | Target_Typ : Entity_Id; | |
1639 | Source_Typ : Entity_Id := Empty) | |
1640 | is | |
1641 | begin | |
1642 | Apply_Selected_Range_Checks | |
1643 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
1644 | end Apply_Range_Check; | |
1645 | ||
1646 | ------------------------------ | |
1647 | -- Apply_Scalar_Range_Check -- | |
1648 | ------------------------------ | |
1649 | ||
feff2f05 | 1650 | -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag |
1651 | -- off if it is already set on. | |
ee6ba406 | 1652 | |
1653 | procedure Apply_Scalar_Range_Check | |
1654 | (Expr : Node_Id; | |
1655 | Target_Typ : Entity_Id; | |
1656 | Source_Typ : Entity_Id := Empty; | |
1657 | Fixed_Int : Boolean := False) | |
1658 | is | |
1659 | Parnt : constant Node_Id := Parent (Expr); | |
1660 | S_Typ : Entity_Id; | |
1661 | Arr : Node_Id := Empty; -- initialize to prevent warning | |
1662 | Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning | |
1663 | OK : Boolean; | |
1664 | ||
1665 | Is_Subscr_Ref : Boolean; | |
1666 | -- Set true if Expr is a subscript | |
1667 | ||
1668 | Is_Unconstrained_Subscr_Ref : Boolean; | |
1669 | -- Set true if Expr is a subscript of an unconstrained array. In this | |
1670 | -- case we do not attempt to do an analysis of the value against the | |
1671 | -- range of the subscript, since we don't know the actual subtype. | |
1672 | ||
1673 | Int_Real : Boolean; | |
feff2f05 | 1674 | -- Set to True if Expr should be regarded as a real value even though |
1675 | -- the type of Expr might be discrete. | |
ee6ba406 | 1676 | |
1677 | procedure Bad_Value; | |
1678 | -- Procedure called if value is determined to be out of range | |
1679 | ||
9dfe12ae | 1680 | --------------- |
1681 | -- Bad_Value -- | |
1682 | --------------- | |
1683 | ||
ee6ba406 | 1684 | procedure Bad_Value is |
1685 | begin | |
1686 | Apply_Compile_Time_Constraint_Error | |
f15731c4 | 1687 | (Expr, "value not in range of}?", CE_Range_Check_Failed, |
ee6ba406 | 1688 | Ent => Target_Typ, |
1689 | Typ => Target_Typ); | |
1690 | end Bad_Value; | |
1691 | ||
9dfe12ae | 1692 | -- Start of processing for Apply_Scalar_Range_Check |
1693 | ||
ee6ba406 | 1694 | begin |
2af58f67 | 1695 | -- Return if check obviously not needed |
ee6ba406 | 1696 | |
2af58f67 | 1697 | if |
1698 | -- Not needed inside generic | |
ee6ba406 | 1699 | |
2af58f67 | 1700 | Inside_A_Generic |
1701 | ||
1702 | -- Not needed if previous error | |
1703 | ||
1704 | or else Target_Typ = Any_Type | |
1705 | or else Nkind (Expr) = N_Error | |
1706 | ||
1707 | -- Not needed for non-scalar type | |
1708 | ||
1709 | or else not Is_Scalar_Type (Target_Typ) | |
1710 | ||
1711 | -- Not needed if we know node raises CE already | |
1712 | ||
1713 | or else Raises_Constraint_Error (Expr) | |
ee6ba406 | 1714 | then |
1715 | return; | |
1716 | end if; | |
1717 | ||
1718 | -- Now, see if checks are suppressed | |
1719 | ||
1720 | Is_Subscr_Ref := | |
1721 | Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component; | |
1722 | ||
1723 | if Is_Subscr_Ref then | |
1724 | Arr := Prefix (Parnt); | |
1725 | Arr_Typ := Get_Actual_Subtype_If_Available (Arr); | |
1726 | end if; | |
1727 | ||
1728 | if not Do_Range_Check (Expr) then | |
1729 | ||
1730 | -- Subscript reference. Check for Index_Checks suppressed | |
1731 | ||
1732 | if Is_Subscr_Ref then | |
1733 | ||
1734 | -- Check array type and its base type | |
1735 | ||
1736 | if Index_Checks_Suppressed (Arr_Typ) | |
9dfe12ae | 1737 | or else Index_Checks_Suppressed (Base_Type (Arr_Typ)) |
ee6ba406 | 1738 | then |
1739 | return; | |
1740 | ||
1741 | -- Check array itself if it is an entity name | |
1742 | ||
1743 | elsif Is_Entity_Name (Arr) | |
9dfe12ae | 1744 | and then Index_Checks_Suppressed (Entity (Arr)) |
ee6ba406 | 1745 | then |
1746 | return; | |
1747 | ||
1748 | -- Check expression itself if it is an entity name | |
1749 | ||
1750 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 1751 | and then Index_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 1752 | then |
1753 | return; | |
1754 | end if; | |
1755 | ||
1756 | -- All other cases, check for Range_Checks suppressed | |
1757 | ||
1758 | else | |
1759 | -- Check target type and its base type | |
1760 | ||
1761 | if Range_Checks_Suppressed (Target_Typ) | |
9dfe12ae | 1762 | or else Range_Checks_Suppressed (Base_Type (Target_Typ)) |
ee6ba406 | 1763 | then |
1764 | return; | |
1765 | ||
1766 | -- Check expression itself if it is an entity name | |
1767 | ||
1768 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 1769 | and then Range_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 1770 | then |
1771 | return; | |
1772 | ||
feff2f05 | 1773 | -- If Expr is part of an assignment statement, then check left |
1774 | -- side of assignment if it is an entity name. | |
ee6ba406 | 1775 | |
1776 | elsif Nkind (Parnt) = N_Assignment_Statement | |
1777 | and then Is_Entity_Name (Name (Parnt)) | |
9dfe12ae | 1778 | and then Range_Checks_Suppressed (Entity (Name (Parnt))) |
ee6ba406 | 1779 | then |
1780 | return; | |
1781 | end if; | |
1782 | end if; | |
1783 | end if; | |
1784 | ||
9dfe12ae | 1785 | -- Do not set range checks if they are killed |
1786 | ||
1787 | if Nkind (Expr) = N_Unchecked_Type_Conversion | |
1788 | and then Kill_Range_Check (Expr) | |
1789 | then | |
1790 | return; | |
1791 | end if; | |
1792 | ||
1793 | -- Do not set range checks for any values from System.Scalar_Values | |
1794 | -- since the whole idea of such values is to avoid checking them! | |
1795 | ||
1796 | if Is_Entity_Name (Expr) | |
1797 | and then Is_RTU (Scope (Entity (Expr)), System_Scalar_Values) | |
1798 | then | |
1799 | return; | |
1800 | end if; | |
1801 | ||
ee6ba406 | 1802 | -- Now see if we need a check |
1803 | ||
1804 | if No (Source_Typ) then | |
1805 | S_Typ := Etype (Expr); | |
1806 | else | |
1807 | S_Typ := Source_Typ; | |
1808 | end if; | |
1809 | ||
1810 | if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then | |
1811 | return; | |
1812 | end if; | |
1813 | ||
1814 | Is_Unconstrained_Subscr_Ref := | |
1815 | Is_Subscr_Ref and then not Is_Constrained (Arr_Typ); | |
1816 | ||
feff2f05 | 1817 | -- Always do a range check if the source type includes infinities and |
1818 | -- the target type does not include infinities. We do not do this if | |
1819 | -- range checks are killed. | |
ee6ba406 | 1820 | |
1821 | if Is_Floating_Point_Type (S_Typ) | |
1822 | and then Has_Infinities (S_Typ) | |
1823 | and then not Has_Infinities (Target_Typ) | |
1824 | then | |
1825 | Enable_Range_Check (Expr); | |
1826 | end if; | |
1827 | ||
feff2f05 | 1828 | -- Return if we know expression is definitely in the range of the target |
1829 | -- type as determined by Determine_Range. Right now we only do this for | |
1830 | -- discrete types, and not fixed-point or floating-point types. | |
ee6ba406 | 1831 | |
f2a06be9 | 1832 | -- The additional less-precise tests below catch these cases |
ee6ba406 | 1833 | |
feff2f05 | 1834 | -- Note: skip this if we are given a source_typ, since the point of |
1835 | -- supplying a Source_Typ is to stop us looking at the expression. | |
1836 | -- We could sharpen this test to be out parameters only ??? | |
ee6ba406 | 1837 | |
1838 | if Is_Discrete_Type (Target_Typ) | |
1839 | and then Is_Discrete_Type (Etype (Expr)) | |
1840 | and then not Is_Unconstrained_Subscr_Ref | |
1841 | and then No (Source_Typ) | |
1842 | then | |
1843 | declare | |
1844 | Tlo : constant Node_Id := Type_Low_Bound (Target_Typ); | |
1845 | Thi : constant Node_Id := Type_High_Bound (Target_Typ); | |
1846 | Lo : Uint; | |
1847 | Hi : Uint; | |
1848 | ||
1849 | begin | |
1850 | if Compile_Time_Known_Value (Tlo) | |
1851 | and then Compile_Time_Known_Value (Thi) | |
1852 | then | |
9dfe12ae | 1853 | declare |
1854 | Lov : constant Uint := Expr_Value (Tlo); | |
1855 | Hiv : constant Uint := Expr_Value (Thi); | |
ee6ba406 | 1856 | |
9dfe12ae | 1857 | begin |
1858 | -- If range is null, we for sure have a constraint error | |
1859 | -- (we don't even need to look at the value involved, | |
1860 | -- since all possible values will raise CE). | |
1861 | ||
1862 | if Lov > Hiv then | |
1863 | Bad_Value; | |
1864 | return; | |
1865 | end if; | |
1866 | ||
1867 | -- Otherwise determine range of value | |
1868 | ||
1869 | Determine_Range (Expr, OK, Lo, Hi); | |
1870 | ||
1871 | if OK then | |
1872 | ||
1873 | -- If definitely in range, all OK | |
ee6ba406 | 1874 | |
ee6ba406 | 1875 | if Lo >= Lov and then Hi <= Hiv then |
1876 | return; | |
1877 | ||
9dfe12ae | 1878 | -- If definitely not in range, warn |
1879 | ||
ee6ba406 | 1880 | elsif Lov > Hi or else Hiv < Lo then |
1881 | Bad_Value; | |
1882 | return; | |
9dfe12ae | 1883 | |
1884 | -- Otherwise we don't know | |
1885 | ||
1886 | else | |
1887 | null; | |
ee6ba406 | 1888 | end if; |
9dfe12ae | 1889 | end if; |
1890 | end; | |
ee6ba406 | 1891 | end if; |
1892 | end; | |
1893 | end if; | |
1894 | ||
1895 | Int_Real := | |
1896 | Is_Floating_Point_Type (S_Typ) | |
1897 | or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int); | |
1898 | ||
1899 | -- Check if we can determine at compile time whether Expr is in the | |
9dfe12ae | 1900 | -- range of the target type. Note that if S_Typ is within the bounds |
1901 | -- of Target_Typ then this must be the case. This check is meaningful | |
1902 | -- only if this is not a conversion between integer and real types. | |
ee6ba406 | 1903 | |
1904 | if not Is_Unconstrained_Subscr_Ref | |
1905 | and then | |
1906 | Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ) | |
1907 | and then | |
1908 | (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int) | |
1909 | or else | |
1910 | Is_In_Range (Expr, Target_Typ, Fixed_Int, Int_Real)) | |
1911 | then | |
1912 | return; | |
1913 | ||
1914 | elsif Is_Out_Of_Range (Expr, Target_Typ, Fixed_Int, Int_Real) then | |
1915 | Bad_Value; | |
1916 | return; | |
1917 | ||
feff2f05 | 1918 | -- In the floating-point case, we only do range checks if the type is |
1919 | -- constrained. We definitely do NOT want range checks for unconstrained | |
1920 | -- types, since we want to have infinities | |
ee6ba406 | 1921 | |
9dfe12ae | 1922 | elsif Is_Floating_Point_Type (S_Typ) then |
1923 | if Is_Constrained (S_Typ) then | |
1924 | Enable_Range_Check (Expr); | |
1925 | end if; | |
ee6ba406 | 1926 | |
9dfe12ae | 1927 | -- For all other cases we enable a range check unconditionally |
ee6ba406 | 1928 | |
1929 | else | |
1930 | Enable_Range_Check (Expr); | |
1931 | return; | |
1932 | end if; | |
ee6ba406 | 1933 | end Apply_Scalar_Range_Check; |
1934 | ||
1935 | ---------------------------------- | |
1936 | -- Apply_Selected_Length_Checks -- | |
1937 | ---------------------------------- | |
1938 | ||
1939 | procedure Apply_Selected_Length_Checks | |
1940 | (Ck_Node : Node_Id; | |
1941 | Target_Typ : Entity_Id; | |
1942 | Source_Typ : Entity_Id; | |
1943 | Do_Static : Boolean) | |
1944 | is | |
1945 | Cond : Node_Id; | |
1946 | R_Result : Check_Result; | |
1947 | R_Cno : Node_Id; | |
1948 | ||
1949 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
1950 | Checks_On : constant Boolean := | |
1951 | (not Index_Checks_Suppressed (Target_Typ)) | |
1952 | or else | |
1953 | (not Length_Checks_Suppressed (Target_Typ)); | |
1954 | ||
1955 | begin | |
f15731c4 | 1956 | if not Expander_Active then |
ee6ba406 | 1957 | return; |
1958 | end if; | |
1959 | ||
1960 | R_Result := | |
1961 | Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
1962 | ||
1963 | for J in 1 .. 2 loop | |
ee6ba406 | 1964 | R_Cno := R_Result (J); |
1965 | exit when No (R_Cno); | |
1966 | ||
1967 | -- A length check may mention an Itype which is attached to a | |
1968 | -- subsequent node. At the top level in a package this can cause | |
1969 | -- an order-of-elaboration problem, so we make sure that the itype | |
1970 | -- is referenced now. | |
1971 | ||
1972 | if Ekind (Current_Scope) = E_Package | |
1973 | and then Is_Compilation_Unit (Current_Scope) | |
1974 | then | |
1975 | Ensure_Defined (Target_Typ, Ck_Node); | |
1976 | ||
1977 | if Present (Source_Typ) then | |
1978 | Ensure_Defined (Source_Typ, Ck_Node); | |
1979 | ||
1980 | elsif Is_Itype (Etype (Ck_Node)) then | |
1981 | Ensure_Defined (Etype (Ck_Node), Ck_Node); | |
1982 | end if; | |
1983 | end if; | |
1984 | ||
feff2f05 | 1985 | -- If the item is a conditional raise of constraint error, then have |
1986 | -- a look at what check is being performed and ??? | |
ee6ba406 | 1987 | |
1988 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
1989 | and then Present (Condition (R_Cno)) | |
1990 | then | |
1991 | Cond := Condition (R_Cno); | |
1992 | ||
0577b0b1 | 1993 | -- Case where node does not now have a dynamic check |
ee6ba406 | 1994 | |
0577b0b1 | 1995 | if not Has_Dynamic_Length_Check (Ck_Node) then |
1996 | ||
1997 | -- If checks are on, just insert the check | |
1998 | ||
1999 | if Checks_On then | |
2000 | Insert_Action (Ck_Node, R_Cno); | |
2001 | ||
2002 | if not Do_Static then | |
2003 | Set_Has_Dynamic_Length_Check (Ck_Node); | |
2004 | end if; | |
2005 | ||
2006 | -- If checks are off, then analyze the length check after | |
2007 | -- temporarily attaching it to the tree in case the relevant | |
2008 | -- condition can be evaluted at compile time. We still want a | |
2009 | -- compile time warning in this case. | |
2010 | ||
2011 | else | |
2012 | Set_Parent (R_Cno, Ck_Node); | |
2013 | Analyze (R_Cno); | |
ee6ba406 | 2014 | end if; |
ee6ba406 | 2015 | end if; |
2016 | ||
2017 | -- Output a warning if the condition is known to be True | |
2018 | ||
2019 | if Is_Entity_Name (Cond) | |
2020 | and then Entity (Cond) = Standard_True | |
2021 | then | |
2022 | Apply_Compile_Time_Constraint_Error | |
2023 | (Ck_Node, "wrong length for array of}?", | |
f15731c4 | 2024 | CE_Length_Check_Failed, |
ee6ba406 | 2025 | Ent => Target_Typ, |
2026 | Typ => Target_Typ); | |
2027 | ||
2028 | -- If we were only doing a static check, or if checks are not | |
2029 | -- on, then we want to delete the check, since it is not needed. | |
2030 | -- We do this by replacing the if statement by a null statement | |
2031 | ||
2032 | elsif Do_Static or else not Checks_On then | |
00c403ee | 2033 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 2034 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
2035 | end if; | |
2036 | ||
2037 | else | |
2038 | Install_Static_Check (R_Cno, Loc); | |
2039 | end if; | |
ee6ba406 | 2040 | end loop; |
ee6ba406 | 2041 | end Apply_Selected_Length_Checks; |
2042 | ||
2043 | --------------------------------- | |
2044 | -- Apply_Selected_Range_Checks -- | |
2045 | --------------------------------- | |
2046 | ||
2047 | procedure Apply_Selected_Range_Checks | |
2048 | (Ck_Node : Node_Id; | |
2049 | Target_Typ : Entity_Id; | |
2050 | Source_Typ : Entity_Id; | |
2051 | Do_Static : Boolean) | |
2052 | is | |
2053 | Cond : Node_Id; | |
2054 | R_Result : Check_Result; | |
2055 | R_Cno : Node_Id; | |
2056 | ||
2057 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
2058 | Checks_On : constant Boolean := | |
2059 | (not Index_Checks_Suppressed (Target_Typ)) | |
2060 | or else | |
2061 | (not Range_Checks_Suppressed (Target_Typ)); | |
2062 | ||
2063 | begin | |
2064 | if not Expander_Active or else not Checks_On then | |
2065 | return; | |
2066 | end if; | |
2067 | ||
2068 | R_Result := | |
2069 | Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
2070 | ||
2071 | for J in 1 .. 2 loop | |
2072 | ||
2073 | R_Cno := R_Result (J); | |
2074 | exit when No (R_Cno); | |
2075 | ||
feff2f05 | 2076 | -- If the item is a conditional raise of constraint error, then have |
2077 | -- a look at what check is being performed and ??? | |
ee6ba406 | 2078 | |
2079 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
2080 | and then Present (Condition (R_Cno)) | |
2081 | then | |
2082 | Cond := Condition (R_Cno); | |
2083 | ||
2084 | if not Has_Dynamic_Range_Check (Ck_Node) then | |
2085 | Insert_Action (Ck_Node, R_Cno); | |
2086 | ||
2087 | if not Do_Static then | |
2088 | Set_Has_Dynamic_Range_Check (Ck_Node); | |
2089 | end if; | |
2090 | end if; | |
2091 | ||
2092 | -- Output a warning if the condition is known to be True | |
2093 | ||
2094 | if Is_Entity_Name (Cond) | |
2095 | and then Entity (Cond) = Standard_True | |
2096 | then | |
feff2f05 | 2097 | -- Since an N_Range is technically not an expression, we have |
2098 | -- to set one of the bounds to C_E and then just flag the | |
2099 | -- N_Range. The warning message will point to the lower bound | |
2100 | -- and complain about a range, which seems OK. | |
ee6ba406 | 2101 | |
2102 | if Nkind (Ck_Node) = N_Range then | |
2103 | Apply_Compile_Time_Constraint_Error | |
2104 | (Low_Bound (Ck_Node), "static range out of bounds of}?", | |
f15731c4 | 2105 | CE_Range_Check_Failed, |
ee6ba406 | 2106 | Ent => Target_Typ, |
2107 | Typ => Target_Typ); | |
2108 | ||
2109 | Set_Raises_Constraint_Error (Ck_Node); | |
2110 | ||
2111 | else | |
2112 | Apply_Compile_Time_Constraint_Error | |
2113 | (Ck_Node, "static value out of range of}?", | |
f15731c4 | 2114 | CE_Range_Check_Failed, |
ee6ba406 | 2115 | Ent => Target_Typ, |
2116 | Typ => Target_Typ); | |
2117 | end if; | |
2118 | ||
2119 | -- If we were only doing a static check, or if checks are not | |
2120 | -- on, then we want to delete the check, since it is not needed. | |
2121 | -- We do this by replacing the if statement by a null statement | |
2122 | ||
2123 | elsif Do_Static or else not Checks_On then | |
00c403ee | 2124 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 2125 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
2126 | end if; | |
2127 | ||
2128 | else | |
2129 | Install_Static_Check (R_Cno, Loc); | |
2130 | end if; | |
ee6ba406 | 2131 | end loop; |
ee6ba406 | 2132 | end Apply_Selected_Range_Checks; |
2133 | ||
2134 | ------------------------------- | |
2135 | -- Apply_Static_Length_Check -- | |
2136 | ------------------------------- | |
2137 | ||
2138 | procedure Apply_Static_Length_Check | |
2139 | (Expr : Node_Id; | |
2140 | Target_Typ : Entity_Id; | |
2141 | Source_Typ : Entity_Id := Empty) | |
2142 | is | |
2143 | begin | |
2144 | Apply_Selected_Length_Checks | |
2145 | (Expr, Target_Typ, Source_Typ, Do_Static => True); | |
2146 | end Apply_Static_Length_Check; | |
2147 | ||
2148 | ------------------------------------- | |
2149 | -- Apply_Subscript_Validity_Checks -- | |
2150 | ------------------------------------- | |
2151 | ||
2152 | procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is | |
2153 | Sub : Node_Id; | |
2154 | ||
2155 | begin | |
2156 | pragma Assert (Nkind (Expr) = N_Indexed_Component); | |
2157 | ||
2158 | -- Loop through subscripts | |
2159 | ||
2160 | Sub := First (Expressions (Expr)); | |
2161 | while Present (Sub) loop | |
2162 | ||
feff2f05 | 2163 | -- Check one subscript. Note that we do not worry about enumeration |
2164 | -- type with holes, since we will convert the value to a Pos value | |
2165 | -- for the subscript, and that convert will do the necessary validity | |
2166 | -- check. | |
ee6ba406 | 2167 | |
2168 | Ensure_Valid (Sub, Holes_OK => True); | |
2169 | ||
2170 | -- Move to next subscript | |
2171 | ||
2172 | Sub := Next (Sub); | |
2173 | end loop; | |
2174 | end Apply_Subscript_Validity_Checks; | |
2175 | ||
2176 | ---------------------------------- | |
2177 | -- Apply_Type_Conversion_Checks -- | |
2178 | ---------------------------------- | |
2179 | ||
2180 | procedure Apply_Type_Conversion_Checks (N : Node_Id) is | |
2181 | Target_Type : constant Entity_Id := Etype (N); | |
2182 | Target_Base : constant Entity_Id := Base_Type (Target_Type); | |
9dfe12ae | 2183 | Expr : constant Node_Id := Expression (N); |
2184 | Expr_Type : constant Entity_Id := Etype (Expr); | |
ee6ba406 | 2185 | |
2186 | begin | |
2187 | if Inside_A_Generic then | |
2188 | return; | |
2189 | ||
f15731c4 | 2190 | -- Skip these checks if serious errors detected, there are some nasty |
ee6ba406 | 2191 | -- situations of incomplete trees that blow things up. |
2192 | ||
f15731c4 | 2193 | elsif Serious_Errors_Detected > 0 then |
ee6ba406 | 2194 | return; |
2195 | ||
feff2f05 | 2196 | -- Scalar type conversions of the form Target_Type (Expr) require a |
2197 | -- range check if we cannot be sure that Expr is in the base type of | |
2198 | -- Target_Typ and also that Expr is in the range of Target_Typ. These | |
2199 | -- are not quite the same condition from an implementation point of | |
2200 | -- view, but clearly the second includes the first. | |
ee6ba406 | 2201 | |
2202 | elsif Is_Scalar_Type (Target_Type) then | |
2203 | declare | |
2204 | Conv_OK : constant Boolean := Conversion_OK (N); | |
feff2f05 | 2205 | -- If the Conversion_OK flag on the type conversion is set and no |
2206 | -- floating point type is involved in the type conversion then | |
2207 | -- fixed point values must be read as integral values. | |
ee6ba406 | 2208 | |
5329ca64 | 2209 | Float_To_Int : constant Boolean := |
2210 | Is_Floating_Point_Type (Expr_Type) | |
2211 | and then Is_Integer_Type (Target_Type); | |
2212 | ||
ee6ba406 | 2213 | begin |
ee6ba406 | 2214 | if not Overflow_Checks_Suppressed (Target_Base) |
2215 | and then not In_Subrange_Of (Expr_Type, Target_Base, Conv_OK) | |
5329ca64 | 2216 | and then not Float_To_Int |
ee6ba406 | 2217 | then |
00c403ee | 2218 | Activate_Overflow_Check (N); |
ee6ba406 | 2219 | end if; |
2220 | ||
2221 | if not Range_Checks_Suppressed (Target_Type) | |
2222 | and then not Range_Checks_Suppressed (Expr_Type) | |
2223 | then | |
5329ca64 | 2224 | if Float_To_Int then |
2225 | Apply_Float_Conversion_Check (Expr, Target_Type); | |
2226 | else | |
2227 | Apply_Scalar_Range_Check | |
2228 | (Expr, Target_Type, Fixed_Int => Conv_OK); | |
2229 | end if; | |
ee6ba406 | 2230 | end if; |
2231 | end; | |
2232 | ||
2233 | elsif Comes_From_Source (N) | |
2234 | and then Is_Record_Type (Target_Type) | |
2235 | and then Is_Derived_Type (Target_Type) | |
2236 | and then not Is_Tagged_Type (Target_Type) | |
2237 | and then not Is_Constrained (Target_Type) | |
9dfe12ae | 2238 | and then Present (Stored_Constraint (Target_Type)) |
ee6ba406 | 2239 | then |
9dfe12ae | 2240 | -- An unconstrained derived type may have inherited discriminant |
2241 | -- Build an actual discriminant constraint list using the stored | |
ee6ba406 | 2242 | -- constraint, to verify that the expression of the parent type |
2243 | -- satisfies the constraints imposed by the (unconstrained!) | |
2244 | -- derived type. This applies to value conversions, not to view | |
2245 | -- conversions of tagged types. | |
2246 | ||
2247 | declare | |
9dfe12ae | 2248 | Loc : constant Source_Ptr := Sloc (N); |
2249 | Cond : Node_Id; | |
2250 | Constraint : Elmt_Id; | |
2251 | Discr_Value : Node_Id; | |
2252 | Discr : Entity_Id; | |
2253 | ||
2254 | New_Constraints : constant Elist_Id := New_Elmt_List; | |
2255 | Old_Constraints : constant Elist_Id := | |
2256 | Discriminant_Constraint (Expr_Type); | |
ee6ba406 | 2257 | |
2258 | begin | |
9dfe12ae | 2259 | Constraint := First_Elmt (Stored_Constraint (Target_Type)); |
ee6ba406 | 2260 | while Present (Constraint) loop |
2261 | Discr_Value := Node (Constraint); | |
2262 | ||
2263 | if Is_Entity_Name (Discr_Value) | |
2264 | and then Ekind (Entity (Discr_Value)) = E_Discriminant | |
2265 | then | |
2266 | Discr := Corresponding_Discriminant (Entity (Discr_Value)); | |
2267 | ||
2268 | if Present (Discr) | |
2269 | and then Scope (Discr) = Base_Type (Expr_Type) | |
2270 | then | |
2271 | -- Parent is constrained by new discriminant. Obtain | |
feff2f05 | 2272 | -- Value of original discriminant in expression. If the |
2273 | -- new discriminant has been used to constrain more than | |
2274 | -- one of the stored discriminants, this will provide the | |
2275 | -- required consistency check. | |
ee6ba406 | 2276 | |
2277 | Append_Elmt ( | |
2278 | Make_Selected_Component (Loc, | |
2279 | Prefix => | |
9dfe12ae | 2280 | Duplicate_Subexpr_No_Checks |
2281 | (Expr, Name_Req => True), | |
ee6ba406 | 2282 | Selector_Name => |
2283 | Make_Identifier (Loc, Chars (Discr))), | |
2284 | New_Constraints); | |
2285 | ||
2286 | else | |
2287 | -- Discriminant of more remote ancestor ??? | |
2288 | ||
2289 | return; | |
2290 | end if; | |
2291 | ||
feff2f05 | 2292 | -- Derived type definition has an explicit value for this |
2293 | -- stored discriminant. | |
ee6ba406 | 2294 | |
2295 | else | |
2296 | Append_Elmt | |
9dfe12ae | 2297 | (Duplicate_Subexpr_No_Checks (Discr_Value), |
2298 | New_Constraints); | |
ee6ba406 | 2299 | end if; |
2300 | ||
2301 | Next_Elmt (Constraint); | |
2302 | end loop; | |
2303 | ||
2304 | -- Use the unconstrained expression type to retrieve the | |
2305 | -- discriminants of the parent, and apply momentarily the | |
2306 | -- discriminant constraint synthesized above. | |
2307 | ||
2308 | Set_Discriminant_Constraint (Expr_Type, New_Constraints); | |
2309 | Cond := Build_Discriminant_Checks (Expr, Expr_Type); | |
2310 | Set_Discriminant_Constraint (Expr_Type, Old_Constraints); | |
2311 | ||
2312 | Insert_Action (N, | |
f15731c4 | 2313 | Make_Raise_Constraint_Error (Loc, |
2314 | Condition => Cond, | |
2315 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 2316 | end; |
2317 | ||
feff2f05 | 2318 | -- For arrays, conversions are applied during expansion, to take into |
2319 | -- accounts changes of representation. The checks become range checks on | |
2320 | -- the base type or length checks on the subtype, depending on whether | |
2321 | -- the target type is unconstrained or constrained. | |
ee6ba406 | 2322 | |
2323 | else | |
2324 | null; | |
2325 | end if; | |
ee6ba406 | 2326 | end Apply_Type_Conversion_Checks; |
2327 | ||
2328 | ---------------------------------------------- | |
2329 | -- Apply_Universal_Integer_Attribute_Checks -- | |
2330 | ---------------------------------------------- | |
2331 | ||
2332 | procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is | |
2333 | Loc : constant Source_Ptr := Sloc (N); | |
2334 | Typ : constant Entity_Id := Etype (N); | |
2335 | ||
2336 | begin | |
2337 | if Inside_A_Generic then | |
2338 | return; | |
2339 | ||
2340 | -- Nothing to do if checks are suppressed | |
2341 | ||
2342 | elsif Range_Checks_Suppressed (Typ) | |
2343 | and then Overflow_Checks_Suppressed (Typ) | |
2344 | then | |
2345 | return; | |
2346 | ||
2347 | -- Nothing to do if the attribute does not come from source. The | |
2348 | -- internal attributes we generate of this type do not need checks, | |
2349 | -- and furthermore the attempt to check them causes some circular | |
2350 | -- elaboration orders when dealing with packed types. | |
2351 | ||
2352 | elsif not Comes_From_Source (N) then | |
2353 | return; | |
2354 | ||
9dfe12ae | 2355 | -- If the prefix is a selected component that depends on a discriminant |
2356 | -- the check may improperly expose a discriminant instead of using | |
2357 | -- the bounds of the object itself. Set the type of the attribute to | |
2358 | -- the base type of the context, so that a check will be imposed when | |
2359 | -- needed (e.g. if the node appears as an index). | |
2360 | ||
2361 | elsif Nkind (Prefix (N)) = N_Selected_Component | |
2362 | and then Ekind (Typ) = E_Signed_Integer_Subtype | |
2363 | and then Depends_On_Discriminant (Scalar_Range (Typ)) | |
2364 | then | |
2365 | Set_Etype (N, Base_Type (Typ)); | |
2366 | ||
feff2f05 | 2367 | -- Otherwise, replace the attribute node with a type conversion node |
2368 | -- whose expression is the attribute, retyped to universal integer, and | |
2369 | -- whose subtype mark is the target type. The call to analyze this | |
2370 | -- conversion will set range and overflow checks as required for proper | |
2371 | -- detection of an out of range value. | |
ee6ba406 | 2372 | |
2373 | else | |
2374 | Set_Etype (N, Universal_Integer); | |
2375 | Set_Analyzed (N, True); | |
2376 | ||
2377 | Rewrite (N, | |
2378 | Make_Type_Conversion (Loc, | |
2379 | Subtype_Mark => New_Occurrence_Of (Typ, Loc), | |
2380 | Expression => Relocate_Node (N))); | |
2381 | ||
2382 | Analyze_And_Resolve (N, Typ); | |
2383 | return; | |
2384 | end if; | |
ee6ba406 | 2385 | end Apply_Universal_Integer_Attribute_Checks; |
2386 | ||
2387 | ------------------------------- | |
2388 | -- Build_Discriminant_Checks -- | |
2389 | ------------------------------- | |
2390 | ||
2391 | function Build_Discriminant_Checks | |
2392 | (N : Node_Id; | |
314a23b6 | 2393 | T_Typ : Entity_Id) return Node_Id |
ee6ba406 | 2394 | is |
2395 | Loc : constant Source_Ptr := Sloc (N); | |
2396 | Cond : Node_Id; | |
2397 | Disc : Elmt_Id; | |
2398 | Disc_Ent : Entity_Id; | |
9dfe12ae | 2399 | Dref : Node_Id; |
ee6ba406 | 2400 | Dval : Node_Id; |
2401 | ||
84d0d4a5 | 2402 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id; |
2403 | ||
2404 | ---------------------------------- | |
2405 | -- Aggregate_Discriminant_Value -- | |
2406 | ---------------------------------- | |
2407 | ||
2408 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id is | |
2409 | Assoc : Node_Id; | |
2410 | ||
2411 | begin | |
feff2f05 | 2412 | -- The aggregate has been normalized with named associations. We use |
2413 | -- the Chars field to locate the discriminant to take into account | |
2414 | -- discriminants in derived types, which carry the same name as those | |
2415 | -- in the parent. | |
84d0d4a5 | 2416 | |
2417 | Assoc := First (Component_Associations (N)); | |
2418 | while Present (Assoc) loop | |
2419 | if Chars (First (Choices (Assoc))) = Chars (Disc) then | |
2420 | return Expression (Assoc); | |
2421 | else | |
2422 | Next (Assoc); | |
2423 | end if; | |
2424 | end loop; | |
2425 | ||
2426 | -- Discriminant must have been found in the loop above | |
2427 | ||
2428 | raise Program_Error; | |
2429 | end Aggregate_Discriminant_Val; | |
2430 | ||
2431 | -- Start of processing for Build_Discriminant_Checks | |
2432 | ||
ee6ba406 | 2433 | begin |
84d0d4a5 | 2434 | -- Loop through discriminants evolving the condition |
2435 | ||
ee6ba406 | 2436 | Cond := Empty; |
2437 | Disc := First_Elmt (Discriminant_Constraint (T_Typ)); | |
2438 | ||
9dfe12ae | 2439 | -- For a fully private type, use the discriminants of the parent type |
ee6ba406 | 2440 | |
2441 | if Is_Private_Type (T_Typ) | |
2442 | and then No (Full_View (T_Typ)) | |
2443 | then | |
2444 | Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ))); | |
2445 | else | |
2446 | Disc_Ent := First_Discriminant (T_Typ); | |
2447 | end if; | |
2448 | ||
2449 | while Present (Disc) loop | |
ee6ba406 | 2450 | Dval := Node (Disc); |
2451 | ||
2452 | if Nkind (Dval) = N_Identifier | |
2453 | and then Ekind (Entity (Dval)) = E_Discriminant | |
2454 | then | |
2455 | Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc); | |
2456 | else | |
9dfe12ae | 2457 | Dval := Duplicate_Subexpr_No_Checks (Dval); |
ee6ba406 | 2458 | end if; |
2459 | ||
00f91aef | 2460 | -- If we have an Unchecked_Union node, we can infer the discriminants |
2461 | -- of the node. | |
9dfe12ae | 2462 | |
00f91aef | 2463 | if Is_Unchecked_Union (Base_Type (T_Typ)) then |
2464 | Dref := New_Copy ( | |
2465 | Get_Discriminant_Value ( | |
2466 | First_Discriminant (T_Typ), | |
2467 | T_Typ, | |
2468 | Stored_Constraint (T_Typ))); | |
2469 | ||
84d0d4a5 | 2470 | elsif Nkind (N) = N_Aggregate then |
2471 | Dref := | |
2472 | Duplicate_Subexpr_No_Checks | |
2473 | (Aggregate_Discriminant_Val (Disc_Ent)); | |
2474 | ||
00f91aef | 2475 | else |
2476 | Dref := | |
2477 | Make_Selected_Component (Loc, | |
2478 | Prefix => | |
2479 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), | |
2480 | Selector_Name => | |
2481 | Make_Identifier (Loc, Chars (Disc_Ent))); | |
2482 | ||
2483 | Set_Is_In_Discriminant_Check (Dref); | |
2484 | end if; | |
9dfe12ae | 2485 | |
ee6ba406 | 2486 | Evolve_Or_Else (Cond, |
2487 | Make_Op_Ne (Loc, | |
9dfe12ae | 2488 | Left_Opnd => Dref, |
ee6ba406 | 2489 | Right_Opnd => Dval)); |
2490 | ||
2491 | Next_Elmt (Disc); | |
2492 | Next_Discriminant (Disc_Ent); | |
2493 | end loop; | |
2494 | ||
2495 | return Cond; | |
2496 | end Build_Discriminant_Checks; | |
2497 | ||
13dbf220 | 2498 | ------------------ |
2499 | -- Check_Needed -- | |
2500 | ------------------ | |
2501 | ||
2502 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean is | |
2503 | N : Node_Id; | |
2504 | P : Node_Id; | |
2505 | K : Node_Kind; | |
2506 | L : Node_Id; | |
2507 | R : Node_Id; | |
2508 | ||
2509 | begin | |
2510 | -- Always check if not simple entity | |
2511 | ||
2512 | if Nkind (Nod) not in N_Has_Entity | |
2513 | or else not Comes_From_Source (Nod) | |
2514 | then | |
2515 | return True; | |
2516 | end if; | |
2517 | ||
2518 | -- Look up tree for short circuit | |
2519 | ||
2520 | N := Nod; | |
2521 | loop | |
2522 | P := Parent (N); | |
2523 | K := Nkind (P); | |
2524 | ||
7b17e51b | 2525 | -- Done if out of subexpression (note that we allow generated stuff |
2526 | -- such as itype declarations in this context, to keep the loop going | |
2527 | -- since we may well have generated such stuff in complex situations. | |
2528 | -- Also done if no parent (probably an error condition, but no point | |
2529 | -- in behaving nasty if we find it!) | |
2530 | ||
2531 | if No (P) | |
2532 | or else (K not in N_Subexpr and then Comes_From_Source (P)) | |
2533 | then | |
13dbf220 | 2534 | return True; |
2535 | ||
7b17e51b | 2536 | -- Or/Or Else case, where test is part of the right operand, or is |
2537 | -- part of one of the actions associated with the right operand, and | |
2538 | -- the left operand is an equality test. | |
13dbf220 | 2539 | |
7b17e51b | 2540 | elsif K = N_Op_Or then |
13dbf220 | 2541 | exit when N = Right_Opnd (P) |
2542 | and then Nkind (Left_Opnd (P)) = N_Op_Eq; | |
2543 | ||
7b17e51b | 2544 | elsif K = N_Or_Else then |
2545 | exit when (N = Right_Opnd (P) | |
2546 | or else | |
2547 | (Is_List_Member (N) | |
2548 | and then List_Containing (N) = Actions (P))) | |
2549 | and then Nkind (Left_Opnd (P)) = N_Op_Eq; | |
13dbf220 | 2550 | |
7b17e51b | 2551 | -- Similar test for the And/And then case, where the left operand |
2552 | -- is an inequality test. | |
2553 | ||
2554 | elsif K = N_Op_And then | |
13dbf220 | 2555 | exit when N = Right_Opnd (P) |
38f5559f | 2556 | and then Nkind (Left_Opnd (P)) = N_Op_Ne; |
7b17e51b | 2557 | |
2558 | elsif K = N_And_Then then | |
2559 | exit when (N = Right_Opnd (P) | |
2560 | or else | |
2561 | (Is_List_Member (N) | |
2562 | and then List_Containing (N) = Actions (P))) | |
2563 | and then Nkind (Left_Opnd (P)) = N_Op_Ne; | |
13dbf220 | 2564 | end if; |
2565 | ||
2566 | N := P; | |
2567 | end loop; | |
2568 | ||
2569 | -- If we fall through the loop, then we have a conditional with an | |
2570 | -- appropriate test as its left operand. So test further. | |
2571 | ||
2572 | L := Left_Opnd (P); | |
13dbf220 | 2573 | R := Right_Opnd (L); |
2574 | L := Left_Opnd (L); | |
2575 | ||
2576 | -- Left operand of test must match original variable | |
2577 | ||
2578 | if Nkind (L) not in N_Has_Entity | |
2579 | or else Entity (L) /= Entity (Nod) | |
2580 | then | |
2581 | return True; | |
2582 | end if; | |
2583 | ||
2af58f67 | 2584 | -- Right operand of test must be key value (zero or null) |
13dbf220 | 2585 | |
2586 | case Check is | |
2587 | when Access_Check => | |
2af58f67 | 2588 | if not Known_Null (R) then |
13dbf220 | 2589 | return True; |
2590 | end if; | |
2591 | ||
2592 | when Division_Check => | |
2593 | if not Compile_Time_Known_Value (R) | |
2594 | or else Expr_Value (R) /= Uint_0 | |
2595 | then | |
2596 | return True; | |
2597 | end if; | |
2af58f67 | 2598 | |
2599 | when others => | |
2600 | raise Program_Error; | |
13dbf220 | 2601 | end case; |
2602 | ||
2603 | -- Here we have the optimizable case, warn if not short-circuited | |
2604 | ||
2605 | if K = N_Op_And or else K = N_Op_Or then | |
2606 | case Check is | |
2607 | when Access_Check => | |
2608 | Error_Msg_N | |
2609 | ("Constraint_Error may be raised (access check)?", | |
2610 | Parent (Nod)); | |
2611 | when Division_Check => | |
2612 | Error_Msg_N | |
2613 | ("Constraint_Error may be raised (zero divide)?", | |
2614 | Parent (Nod)); | |
2af58f67 | 2615 | |
2616 | when others => | |
2617 | raise Program_Error; | |
13dbf220 | 2618 | end case; |
2619 | ||
2620 | if K = N_Op_And then | |
2621 | Error_Msg_N ("use `AND THEN` instead of AND?", P); | |
2622 | else | |
2623 | Error_Msg_N ("use `OR ELSE` instead of OR?", P); | |
2624 | end if; | |
2625 | ||
2626 | -- If not short-circuited, we need the ckeck | |
2627 | ||
2628 | return True; | |
2629 | ||
2630 | -- If short-circuited, we can omit the check | |
2631 | ||
2632 | else | |
2633 | return False; | |
2634 | end if; | |
2635 | end Check_Needed; | |
2636 | ||
ee6ba406 | 2637 | ----------------------------------- |
2638 | -- Check_Valid_Lvalue_Subscripts -- | |
2639 | ----------------------------------- | |
2640 | ||
2641 | procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is | |
2642 | begin | |
2643 | -- Skip this if range checks are suppressed | |
2644 | ||
2645 | if Range_Checks_Suppressed (Etype (Expr)) then | |
2646 | return; | |
2647 | ||
feff2f05 | 2648 | -- Only do this check for expressions that come from source. We assume |
2649 | -- that expander generated assignments explicitly include any necessary | |
2650 | -- checks. Note that this is not just an optimization, it avoids | |
2651 | -- infinite recursions! | |
ee6ba406 | 2652 | |
2653 | elsif not Comes_From_Source (Expr) then | |
2654 | return; | |
2655 | ||
2656 | -- For a selected component, check the prefix | |
2657 | ||
2658 | elsif Nkind (Expr) = N_Selected_Component then | |
2659 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
2660 | return; | |
2661 | ||
2662 | -- Case of indexed component | |
2663 | ||
2664 | elsif Nkind (Expr) = N_Indexed_Component then | |
2665 | Apply_Subscript_Validity_Checks (Expr); | |
2666 | ||
feff2f05 | 2667 | -- Prefix may itself be or contain an indexed component, and these |
2668 | -- subscripts need checking as well. | |
ee6ba406 | 2669 | |
2670 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
2671 | end if; | |
2672 | end Check_Valid_Lvalue_Subscripts; | |
2673 | ||
fa7497e8 | 2674 | ---------------------------------- |
2675 | -- Null_Exclusion_Static_Checks -- | |
2676 | ---------------------------------- | |
2677 | ||
2678 | procedure Null_Exclusion_Static_Checks (N : Node_Id) is | |
0577b0b1 | 2679 | Error_Node : Node_Id; |
2680 | Expr : Node_Id; | |
2681 | Has_Null : constant Boolean := Has_Null_Exclusion (N); | |
2682 | K : constant Node_Kind := Nkind (N); | |
2683 | Typ : Entity_Id; | |
fa7497e8 | 2684 | |
13dbf220 | 2685 | begin |
0577b0b1 | 2686 | pragma Assert |
2687 | (K = N_Component_Declaration | |
2688 | or else K = N_Discriminant_Specification | |
2689 | or else K = N_Function_Specification | |
2690 | or else K = N_Object_Declaration | |
2691 | or else K = N_Parameter_Specification); | |
2692 | ||
2693 | if K = N_Function_Specification then | |
2694 | Typ := Etype (Defining_Entity (N)); | |
2695 | else | |
2696 | Typ := Etype (Defining_Identifier (N)); | |
2697 | end if; | |
fa7497e8 | 2698 | |
13dbf220 | 2699 | case K is |
13dbf220 | 2700 | when N_Component_Declaration => |
2701 | if Present (Access_Definition (Component_Definition (N))) then | |
0577b0b1 | 2702 | Error_Node := Component_Definition (N); |
13dbf220 | 2703 | else |
0577b0b1 | 2704 | Error_Node := Subtype_Indication (Component_Definition (N)); |
13dbf220 | 2705 | end if; |
5329ca64 | 2706 | |
0577b0b1 | 2707 | when N_Discriminant_Specification => |
2708 | Error_Node := Discriminant_Type (N); | |
2709 | ||
2710 | when N_Function_Specification => | |
2711 | Error_Node := Result_Definition (N); | |
2712 | ||
2713 | when N_Object_Declaration => | |
2714 | Error_Node := Object_Definition (N); | |
2715 | ||
2716 | when N_Parameter_Specification => | |
2717 | Error_Node := Parameter_Type (N); | |
2718 | ||
13dbf220 | 2719 | when others => |
2720 | raise Program_Error; | |
2721 | end case; | |
5329ca64 | 2722 | |
0577b0b1 | 2723 | if Has_Null then |
5329ca64 | 2724 | |
0577b0b1 | 2725 | -- Enforce legality rule 3.10 (13): A null exclusion can only be |
2726 | -- applied to an access [sub]type. | |
5329ca64 | 2727 | |
0577b0b1 | 2728 | if not Is_Access_Type (Typ) then |
2729 | Error_Msg_N | |
00c403ee | 2730 | ("`NOT NULL` allowed only for an access type", Error_Node); |
5329ca64 | 2731 | |
feff2f05 | 2732 | -- Enforce legality rule RM 3.10(14/1): A null exclusion can only |
0577b0b1 | 2733 | -- be applied to a [sub]type that does not exclude null already. |
2734 | ||
2735 | elsif Can_Never_Be_Null (Typ) | |
2736 | ||
2737 | -- No need to check itypes that have a null exclusion because | |
2738 | -- they are already examined at their point of creation. | |
2739 | ||
2740 | and then not Is_Itype (Typ) | |
2741 | then | |
00c403ee | 2742 | Error_Msg_NE |
2743 | ("`NOT NULL` not allowed (& already excludes null)", | |
2744 | Error_Node, Typ); | |
0577b0b1 | 2745 | end if; |
13dbf220 | 2746 | end if; |
5329ca64 | 2747 | |
cc60bd16 | 2748 | -- Check that null-excluding objects are always initialized, except for |
2749 | -- deferred constants, for which the expression will appear in the full | |
2750 | -- declaration. | |
13dbf220 | 2751 | |
2752 | if K = N_Object_Declaration | |
84d0d4a5 | 2753 | and then No (Expression (N)) |
cc60bd16 | 2754 | and then not Constant_Present (N) |
feff2f05 | 2755 | and then not No_Initialization (N) |
13dbf220 | 2756 | then |
feff2f05 | 2757 | -- Add an expression that assigns null. This node is needed by |
2758 | -- Apply_Compile_Time_Constraint_Error, which will replace this with | |
2759 | -- a Constraint_Error node. | |
13dbf220 | 2760 | |
2761 | Set_Expression (N, Make_Null (Sloc (N))); | |
2762 | Set_Etype (Expression (N), Etype (Defining_Identifier (N))); | |
5329ca64 | 2763 | |
13dbf220 | 2764 | Apply_Compile_Time_Constraint_Error |
2765 | (N => Expression (N), | |
2766 | Msg => "(Ada 2005) null-excluding objects must be initialized?", | |
2767 | Reason => CE_Null_Not_Allowed); | |
2768 | end if; | |
5329ca64 | 2769 | |
cc60bd16 | 2770 | -- Check that a null-excluding component, formal or object is not being |
2771 | -- assigned a null value. Otherwise generate a warning message and | |
2c145f84 | 2772 | -- replace Expression (N) by an N_Constraint_Error node. |
13dbf220 | 2773 | |
0577b0b1 | 2774 | if K /= N_Function_Specification then |
2775 | Expr := Expression (N); | |
5329ca64 | 2776 | |
2af58f67 | 2777 | if Present (Expr) and then Known_Null (Expr) then |
13dbf220 | 2778 | case K is |
0577b0b1 | 2779 | when N_Component_Declaration | |
2780 | N_Discriminant_Specification => | |
7189d17f | 2781 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 2782 | (N => Expr, |
2af58f67 | 2783 | Msg => "(Ada 2005) null not allowed " & |
0577b0b1 | 2784 | "in null-excluding components?", |
2785 | Reason => CE_Null_Not_Allowed); | |
5329ca64 | 2786 | |
0577b0b1 | 2787 | when N_Object_Declaration => |
7189d17f | 2788 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 2789 | (N => Expr, |
2af58f67 | 2790 | Msg => "(Ada 2005) null not allowed " & |
0577b0b1 | 2791 | "in null-excluding objects?", |
2792 | Reason => CE_Null_Not_Allowed); | |
5329ca64 | 2793 | |
0577b0b1 | 2794 | when N_Parameter_Specification => |
7189d17f | 2795 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 2796 | (N => Expr, |
2af58f67 | 2797 | Msg => "(Ada 2005) null not allowed " & |
0577b0b1 | 2798 | "in null-excluding formals?", |
2799 | Reason => CE_Null_Not_Allowed); | |
13dbf220 | 2800 | |
2801 | when others => | |
2802 | null; | |
5329ca64 | 2803 | end case; |
2804 | end if; | |
0577b0b1 | 2805 | end if; |
fa7497e8 | 2806 | end Null_Exclusion_Static_Checks; |
2807 | ||
9dfe12ae | 2808 | ---------------------------------- |
2809 | -- Conditional_Statements_Begin -- | |
2810 | ---------------------------------- | |
2811 | ||
2812 | procedure Conditional_Statements_Begin is | |
2813 | begin | |
2814 | Saved_Checks_TOS := Saved_Checks_TOS + 1; | |
2815 | ||
feff2f05 | 2816 | -- If stack overflows, kill all checks, that way we know to simply reset |
2817 | -- the number of saved checks to zero on return. This should never occur | |
2818 | -- in practice. | |
9dfe12ae | 2819 | |
2820 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
2821 | Kill_All_Checks; | |
2822 | ||
feff2f05 | 2823 | -- In the normal case, we just make a new stack entry saving the current |
2824 | -- number of saved checks for a later restore. | |
9dfe12ae | 2825 | |
2826 | else | |
2827 | Saved_Checks_Stack (Saved_Checks_TOS) := Num_Saved_Checks; | |
2828 | ||
2829 | if Debug_Flag_CC then | |
2830 | w ("Conditional_Statements_Begin: Num_Saved_Checks = ", | |
2831 | Num_Saved_Checks); | |
2832 | end if; | |
2833 | end if; | |
2834 | end Conditional_Statements_Begin; | |
2835 | ||
2836 | -------------------------------- | |
2837 | -- Conditional_Statements_End -- | |
2838 | -------------------------------- | |
2839 | ||
2840 | procedure Conditional_Statements_End is | |
2841 | begin | |
2842 | pragma Assert (Saved_Checks_TOS > 0); | |
2843 | ||
feff2f05 | 2844 | -- If the saved checks stack overflowed, then we killed all checks, so |
2845 | -- setting the number of saved checks back to zero is correct. This | |
2846 | -- should never occur in practice. | |
9dfe12ae | 2847 | |
2848 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
2849 | Num_Saved_Checks := 0; | |
2850 | ||
feff2f05 | 2851 | -- In the normal case, restore the number of saved checks from the top |
2852 | -- stack entry. | |
9dfe12ae | 2853 | |
2854 | else | |
2855 | Num_Saved_Checks := Saved_Checks_Stack (Saved_Checks_TOS); | |
2856 | if Debug_Flag_CC then | |
2857 | w ("Conditional_Statements_End: Num_Saved_Checks = ", | |
2858 | Num_Saved_Checks); | |
2859 | end if; | |
2860 | end if; | |
2861 | ||
2862 | Saved_Checks_TOS := Saved_Checks_TOS - 1; | |
2863 | end Conditional_Statements_End; | |
2864 | ||
ee6ba406 | 2865 | --------------------- |
2866 | -- Determine_Range -- | |
2867 | --------------------- | |
2868 | ||
6af1bdbc | 2869 | Cache_Size : constant := 2 ** 10; |
ee6ba406 | 2870 | type Cache_Index is range 0 .. Cache_Size - 1; |
2871 | -- Determine size of below cache (power of 2 is more efficient!) | |
2872 | ||
2873 | Determine_Range_Cache_N : array (Cache_Index) of Node_Id; | |
2874 | Determine_Range_Cache_Lo : array (Cache_Index) of Uint; | |
2875 | Determine_Range_Cache_Hi : array (Cache_Index) of Uint; | |
feff2f05 | 2876 | -- The above arrays are used to implement a small direct cache for |
2877 | -- Determine_Range calls. Because of the way Determine_Range recursively | |
2878 | -- traces subexpressions, and because overflow checking calls the routine | |
2879 | -- on the way up the tree, a quadratic behavior can otherwise be | |
2880 | -- encountered in large expressions. The cache entry for node N is stored | |
2881 | -- in the (N mod Cache_Size) entry, and can be validated by checking the | |
2882 | -- actual node value stored there. | |
ee6ba406 | 2883 | |
2884 | procedure Determine_Range | |
2885 | (N : Node_Id; | |
2886 | OK : out Boolean; | |
2887 | Lo : out Uint; | |
2888 | Hi : out Uint) | |
2889 | is | |
8880be85 | 2890 | Typ : constant Entity_Id := Etype (N); |
2891 | ||
2892 | Lo_Left : Uint; | |
2893 | Hi_Left : Uint; | |
2894 | -- Lo and Hi bounds of left operand | |
ee6ba406 | 2895 | |
ee6ba406 | 2896 | Lo_Right : Uint; |
ee6ba406 | 2897 | Hi_Right : Uint; |
8880be85 | 2898 | -- Lo and Hi bounds of right (or only) operand |
2899 | ||
2900 | Bound : Node_Id; | |
2901 | -- Temp variable used to hold a bound node | |
2902 | ||
2903 | Hbound : Uint; | |
2904 | -- High bound of base type of expression | |
2905 | ||
2906 | Lor : Uint; | |
2907 | Hir : Uint; | |
2908 | -- Refined values for low and high bounds, after tightening | |
2909 | ||
2910 | OK1 : Boolean; | |
2911 | -- Used in lower level calls to indicate if call succeeded | |
2912 | ||
2913 | Cindex : Cache_Index; | |
2914 | -- Used to search cache | |
ee6ba406 | 2915 | |
2916 | function OK_Operands return Boolean; | |
2917 | -- Used for binary operators. Determines the ranges of the left and | |
2918 | -- right operands, and if they are both OK, returns True, and puts | |
2919 | -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left | |
2920 | ||
2921 | ----------------- | |
2922 | -- OK_Operands -- | |
2923 | ----------------- | |
2924 | ||
2925 | function OK_Operands return Boolean is | |
2926 | begin | |
2927 | Determine_Range (Left_Opnd (N), OK1, Lo_Left, Hi_Left); | |
2928 | ||
2929 | if not OK1 then | |
2930 | return False; | |
2931 | end if; | |
2932 | ||
2933 | Determine_Range (Right_Opnd (N), OK1, Lo_Right, Hi_Right); | |
2934 | return OK1; | |
2935 | end OK_Operands; | |
2936 | ||
2937 | -- Start of processing for Determine_Range | |
2938 | ||
2939 | begin | |
2940 | -- Prevent junk warnings by initializing range variables | |
2941 | ||
2942 | Lo := No_Uint; | |
2943 | Hi := No_Uint; | |
2944 | Lor := No_Uint; | |
2945 | Hir := No_Uint; | |
2946 | ||
feff2f05 | 2947 | -- If the type is not discrete, or is undefined, then we can't do |
2948 | -- anything about determining the range. | |
ee6ba406 | 2949 | |
2950 | if No (Typ) or else not Is_Discrete_Type (Typ) | |
2951 | or else Error_Posted (N) | |
2952 | then | |
2953 | OK := False; | |
2954 | return; | |
2955 | end if; | |
2956 | ||
2957 | -- For all other cases, we can determine the range | |
2958 | ||
2959 | OK := True; | |
2960 | ||
feff2f05 | 2961 | -- If value is compile time known, then the possible range is the one |
2962 | -- value that we know this expression definitely has! | |
ee6ba406 | 2963 | |
2964 | if Compile_Time_Known_Value (N) then | |
2965 | Lo := Expr_Value (N); | |
2966 | Hi := Lo; | |
2967 | return; | |
2968 | end if; | |
2969 | ||
2970 | -- Return if already in the cache | |
2971 | ||
2972 | Cindex := Cache_Index (N mod Cache_Size); | |
2973 | ||
2974 | if Determine_Range_Cache_N (Cindex) = N then | |
2975 | Lo := Determine_Range_Cache_Lo (Cindex); | |
2976 | Hi := Determine_Range_Cache_Hi (Cindex); | |
2977 | return; | |
2978 | end if; | |
2979 | ||
feff2f05 | 2980 | -- Otherwise, start by finding the bounds of the type of the expression, |
2981 | -- the value cannot be outside this range (if it is, then we have an | |
2982 | -- overflow situation, which is a separate check, we are talking here | |
2983 | -- only about the expression value). | |
ee6ba406 | 2984 | |
feff2f05 | 2985 | -- We use the actual bound unless it is dynamic, in which case use the |
2986 | -- corresponding base type bound if possible. If we can't get a bound | |
2987 | -- then we figure we can't determine the range (a peculiar case, that | |
2988 | -- perhaps cannot happen, but there is no point in bombing in this | |
2989 | -- optimization circuit. | |
8880be85 | 2990 | |
2991 | -- First the low bound | |
ee6ba406 | 2992 | |
2993 | Bound := Type_Low_Bound (Typ); | |
2994 | ||
2995 | if Compile_Time_Known_Value (Bound) then | |
2996 | Lo := Expr_Value (Bound); | |
2997 | ||
2998 | elsif Compile_Time_Known_Value (Type_Low_Bound (Base_Type (Typ))) then | |
2999 | Lo := Expr_Value (Type_Low_Bound (Base_Type (Typ))); | |
3000 | ||
3001 | else | |
3002 | OK := False; | |
3003 | return; | |
3004 | end if; | |
3005 | ||
8880be85 | 3006 | -- Now the high bound |
3007 | ||
ee6ba406 | 3008 | Bound := Type_High_Bound (Typ); |
3009 | ||
8880be85 | 3010 | -- We need the high bound of the base type later on, and this should |
3011 | -- always be compile time known. Again, it is not clear that this | |
3012 | -- can ever be false, but no point in bombing. | |
ee6ba406 | 3013 | |
8880be85 | 3014 | if Compile_Time_Known_Value (Type_High_Bound (Base_Type (Typ))) then |
ee6ba406 | 3015 | Hbound := Expr_Value (Type_High_Bound (Base_Type (Typ))); |
3016 | Hi := Hbound; | |
3017 | ||
3018 | else | |
3019 | OK := False; | |
3020 | return; | |
3021 | end if; | |
3022 | ||
feff2f05 | 3023 | -- If we have a static subtype, then that may have a tighter bound so |
3024 | -- use the upper bound of the subtype instead in this case. | |
8880be85 | 3025 | |
3026 | if Compile_Time_Known_Value (Bound) then | |
3027 | Hi := Expr_Value (Bound); | |
3028 | end if; | |
3029 | ||
feff2f05 | 3030 | -- We may be able to refine this value in certain situations. If any |
3031 | -- refinement is possible, then Lor and Hir are set to possibly tighter | |
3032 | -- bounds, and OK1 is set to True. | |
ee6ba406 | 3033 | |
3034 | case Nkind (N) is | |
3035 | ||
3036 | -- For unary plus, result is limited by range of operand | |
3037 | ||
3038 | when N_Op_Plus => | |
3039 | Determine_Range (Right_Opnd (N), OK1, Lor, Hir); | |
3040 | ||
3041 | -- For unary minus, determine range of operand, and negate it | |
3042 | ||
3043 | when N_Op_Minus => | |
3044 | Determine_Range (Right_Opnd (N), OK1, Lo_Right, Hi_Right); | |
3045 | ||
3046 | if OK1 then | |
3047 | Lor := -Hi_Right; | |
3048 | Hir := -Lo_Right; | |
3049 | end if; | |
3050 | ||
3051 | -- For binary addition, get range of each operand and do the | |
3052 | -- addition to get the result range. | |
3053 | ||
3054 | when N_Op_Add => | |
3055 | if OK_Operands then | |
3056 | Lor := Lo_Left + Lo_Right; | |
3057 | Hir := Hi_Left + Hi_Right; | |
3058 | end if; | |
3059 | ||
feff2f05 | 3060 | -- Division is tricky. The only case we consider is where the right |
3061 | -- operand is a positive constant, and in this case we simply divide | |
3062 | -- the bounds of the left operand | |
ee6ba406 | 3063 | |
3064 | when N_Op_Divide => | |
3065 | if OK_Operands then | |
3066 | if Lo_Right = Hi_Right | |
3067 | and then Lo_Right > 0 | |
3068 | then | |
3069 | Lor := Lo_Left / Lo_Right; | |
3070 | Hir := Hi_Left / Lo_Right; | |
3071 | ||
3072 | else | |
3073 | OK1 := False; | |
3074 | end if; | |
3075 | end if; | |
3076 | ||
feff2f05 | 3077 | -- For binary subtraction, get range of each operand and do the worst |
3078 | -- case subtraction to get the result range. | |
ee6ba406 | 3079 | |
3080 | when N_Op_Subtract => | |
3081 | if OK_Operands then | |
3082 | Lor := Lo_Left - Hi_Right; | |
3083 | Hir := Hi_Left - Lo_Right; | |
3084 | end if; | |
3085 | ||
feff2f05 | 3086 | -- For MOD, if right operand is a positive constant, then result must |
3087 | -- be in the allowable range of mod results. | |
ee6ba406 | 3088 | |
3089 | when N_Op_Mod => | |
3090 | if OK_Operands then | |
9dfe12ae | 3091 | if Lo_Right = Hi_Right |
3092 | and then Lo_Right /= 0 | |
3093 | then | |
ee6ba406 | 3094 | if Lo_Right > 0 then |
3095 | Lor := Uint_0; | |
3096 | Hir := Lo_Right - 1; | |
3097 | ||
9dfe12ae | 3098 | else -- Lo_Right < 0 |
ee6ba406 | 3099 | Lor := Lo_Right + 1; |
3100 | Hir := Uint_0; | |
3101 | end if; | |
3102 | ||
3103 | else | |
3104 | OK1 := False; | |
3105 | end if; | |
3106 | end if; | |
3107 | ||
feff2f05 | 3108 | -- For REM, if right operand is a positive constant, then result must |
3109 | -- be in the allowable range of mod results. | |
ee6ba406 | 3110 | |
3111 | when N_Op_Rem => | |
3112 | if OK_Operands then | |
9dfe12ae | 3113 | if Lo_Right = Hi_Right |
3114 | and then Lo_Right /= 0 | |
3115 | then | |
ee6ba406 | 3116 | declare |
3117 | Dval : constant Uint := (abs Lo_Right) - 1; | |
3118 | ||
3119 | begin | |
3120 | -- The sign of the result depends on the sign of the | |
3121 | -- dividend (but not on the sign of the divisor, hence | |
3122 | -- the abs operation above). | |
3123 | ||
3124 | if Lo_Left < 0 then | |
3125 | Lor := -Dval; | |
3126 | else | |
3127 | Lor := Uint_0; | |
3128 | end if; | |
3129 | ||
3130 | if Hi_Left < 0 then | |
3131 | Hir := Uint_0; | |
3132 | else | |
3133 | Hir := Dval; | |
3134 | end if; | |
3135 | end; | |
3136 | ||
3137 | else | |
3138 | OK1 := False; | |
3139 | end if; | |
3140 | end if; | |
3141 | ||
3142 | -- Attribute reference cases | |
3143 | ||
3144 | when N_Attribute_Reference => | |
3145 | case Attribute_Name (N) is | |
3146 | ||
3147 | -- For Pos/Val attributes, we can refine the range using the | |
3148 | -- possible range of values of the attribute expression | |
3149 | ||
3150 | when Name_Pos | Name_Val => | |
3151 | Determine_Range (First (Expressions (N)), OK1, Lor, Hir); | |
3152 | ||
3153 | -- For Length attribute, use the bounds of the corresponding | |
3154 | -- index type to refine the range. | |
3155 | ||
3156 | when Name_Length => | |
3157 | declare | |
3158 | Atyp : Entity_Id := Etype (Prefix (N)); | |
3159 | Inum : Nat; | |
3160 | Indx : Node_Id; | |
3161 | ||
3162 | LL, LU : Uint; | |
3163 | UL, UU : Uint; | |
3164 | ||
3165 | begin | |
3166 | if Is_Access_Type (Atyp) then | |
3167 | Atyp := Designated_Type (Atyp); | |
3168 | end if; | |
3169 | ||
3170 | -- For string literal, we know exact value | |
3171 | ||
3172 | if Ekind (Atyp) = E_String_Literal_Subtype then | |
3173 | OK := True; | |
3174 | Lo := String_Literal_Length (Atyp); | |
3175 | Hi := String_Literal_Length (Atyp); | |
3176 | return; | |
3177 | end if; | |
3178 | ||
3179 | -- Otherwise check for expression given | |
3180 | ||
3181 | if No (Expressions (N)) then | |
3182 | Inum := 1; | |
3183 | else | |
3184 | Inum := | |
3185 | UI_To_Int (Expr_Value (First (Expressions (N)))); | |
3186 | end if; | |
3187 | ||
3188 | Indx := First_Index (Atyp); | |
3189 | for J in 2 .. Inum loop | |
3190 | Indx := Next_Index (Indx); | |
3191 | end loop; | |
3192 | ||
3193 | Determine_Range | |
3194 | (Type_Low_Bound (Etype (Indx)), OK1, LL, LU); | |
3195 | ||
3196 | if OK1 then | |
3197 | Determine_Range | |
3198 | (Type_High_Bound (Etype (Indx)), OK1, UL, UU); | |
3199 | ||
3200 | if OK1 then | |
3201 | ||
3202 | -- The maximum value for Length is the biggest | |
3203 | -- possible gap between the values of the bounds. | |
3204 | -- But of course, this value cannot be negative. | |
3205 | ||
3206 | Hir := UI_Max (Uint_0, UU - LL); | |
3207 | ||
3208 | -- For constrained arrays, the minimum value for | |
3209 | -- Length is taken from the actual value of the | |
3210 | -- bounds, since the index will be exactly of | |
3211 | -- this subtype. | |
3212 | ||
3213 | if Is_Constrained (Atyp) then | |
3214 | Lor := UI_Max (Uint_0, UL - LU); | |
3215 | ||
3216 | -- For an unconstrained array, the minimum value | |
3217 | -- for length is always zero. | |
3218 | ||
3219 | else | |
3220 | Lor := Uint_0; | |
3221 | end if; | |
3222 | end if; | |
3223 | end if; | |
3224 | end; | |
3225 | ||
3226 | -- No special handling for other attributes | |
3227 | -- Probably more opportunities exist here ??? | |
3228 | ||
3229 | when others => | |
3230 | OK1 := False; | |
3231 | ||
3232 | end case; | |
3233 | ||
feff2f05 | 3234 | -- For type conversion from one discrete type to another, we can |
3235 | -- refine the range using the converted value. | |
ee6ba406 | 3236 | |
3237 | when N_Type_Conversion => | |
3238 | Determine_Range (Expression (N), OK1, Lor, Hir); | |
3239 | ||
3240 | -- Nothing special to do for all other expression kinds | |
3241 | ||
3242 | when others => | |
3243 | OK1 := False; | |
3244 | Lor := No_Uint; | |
3245 | Hir := No_Uint; | |
3246 | end case; | |
3247 | ||
3248 | -- At this stage, if OK1 is true, then we know that the actual | |
3249 | -- result of the computed expression is in the range Lor .. Hir. | |
3250 | -- We can use this to restrict the possible range of results. | |
3251 | ||
3252 | if OK1 then | |
3253 | ||
3254 | -- If the refined value of the low bound is greater than the | |
3255 | -- type high bound, then reset it to the more restrictive | |
3256 | -- value. However, we do NOT do this for the case of a modular | |
3257 | -- type where the possible upper bound on the value is above the | |
3258 | -- base type high bound, because that means the result could wrap. | |
3259 | ||
3260 | if Lor > Lo | |
3261 | and then not (Is_Modular_Integer_Type (Typ) | |
3262 | and then Hir > Hbound) | |
3263 | then | |
3264 | Lo := Lor; | |
3265 | end if; | |
3266 | ||
3267 | -- Similarly, if the refined value of the high bound is less | |
3268 | -- than the value so far, then reset it to the more restrictive | |
3269 | -- value. Again, we do not do this if the refined low bound is | |
3270 | -- negative for a modular type, since this would wrap. | |
3271 | ||
3272 | if Hir < Hi | |
3273 | and then not (Is_Modular_Integer_Type (Typ) | |
3274 | and then Lor < Uint_0) | |
3275 | then | |
3276 | Hi := Hir; | |
3277 | end if; | |
3278 | end if; | |
3279 | ||
3280 | -- Set cache entry for future call and we are all done | |
3281 | ||
3282 | Determine_Range_Cache_N (Cindex) := N; | |
3283 | Determine_Range_Cache_Lo (Cindex) := Lo; | |
3284 | Determine_Range_Cache_Hi (Cindex) := Hi; | |
3285 | return; | |
3286 | ||
3287 | -- If any exception occurs, it means that we have some bug in the compiler | |
3288 | -- possibly triggered by a previous error, or by some unforseen peculiar | |
3289 | -- occurrence. However, this is only an optimization attempt, so there is | |
3290 | -- really no point in crashing the compiler. Instead we just decide, too | |
3291 | -- bad, we can't figure out a range in this case after all. | |
3292 | ||
3293 | exception | |
3294 | when others => | |
3295 | ||
3296 | -- Debug flag K disables this behavior (useful for debugging) | |
3297 | ||
3298 | if Debug_Flag_K then | |
3299 | raise; | |
3300 | else | |
3301 | OK := False; | |
3302 | Lo := No_Uint; | |
3303 | Hi := No_Uint; | |
3304 | return; | |
3305 | end if; | |
ee6ba406 | 3306 | end Determine_Range; |
3307 | ||
3308 | ------------------------------------ | |
3309 | -- Discriminant_Checks_Suppressed -- | |
3310 | ------------------------------------ | |
3311 | ||
3312 | function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is | |
3313 | begin | |
9dfe12ae | 3314 | if Present (E) then |
3315 | if Is_Unchecked_Union (E) then | |
3316 | return True; | |
3317 | elsif Checks_May_Be_Suppressed (E) then | |
3318 | return Is_Check_Suppressed (E, Discriminant_Check); | |
3319 | end if; | |
3320 | end if; | |
3321 | ||
3322 | return Scope_Suppress (Discriminant_Check); | |
ee6ba406 | 3323 | end Discriminant_Checks_Suppressed; |
3324 | ||
3325 | -------------------------------- | |
3326 | -- Division_Checks_Suppressed -- | |
3327 | -------------------------------- | |
3328 | ||
3329 | function Division_Checks_Suppressed (E : Entity_Id) return Boolean is | |
3330 | begin | |
9dfe12ae | 3331 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
3332 | return Is_Check_Suppressed (E, Division_Check); | |
3333 | else | |
3334 | return Scope_Suppress (Division_Check); | |
3335 | end if; | |
ee6ba406 | 3336 | end Division_Checks_Suppressed; |
3337 | ||
3338 | ----------------------------------- | |
3339 | -- Elaboration_Checks_Suppressed -- | |
3340 | ----------------------------------- | |
3341 | ||
3342 | function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is | |
3343 | begin | |
38f5559f | 3344 | -- The complication in this routine is that if we are in the dynamic |
3345 | -- model of elaboration, we also check All_Checks, since All_Checks | |
3346 | -- does not set Elaboration_Check explicitly. | |
3347 | ||
9dfe12ae | 3348 | if Present (E) then |
3349 | if Kill_Elaboration_Checks (E) then | |
3350 | return True; | |
38f5559f | 3351 | |
9dfe12ae | 3352 | elsif Checks_May_Be_Suppressed (E) then |
38f5559f | 3353 | if Is_Check_Suppressed (E, Elaboration_Check) then |
3354 | return True; | |
3355 | elsif Dynamic_Elaboration_Checks then | |
3356 | return Is_Check_Suppressed (E, All_Checks); | |
3357 | else | |
3358 | return False; | |
3359 | end if; | |
9dfe12ae | 3360 | end if; |
3361 | end if; | |
3362 | ||
38f5559f | 3363 | if Scope_Suppress (Elaboration_Check) then |
3364 | return True; | |
3365 | elsif Dynamic_Elaboration_Checks then | |
3366 | return Scope_Suppress (All_Checks); | |
3367 | else | |
3368 | return False; | |
3369 | end if; | |
ee6ba406 | 3370 | end Elaboration_Checks_Suppressed; |
3371 | ||
9dfe12ae | 3372 | --------------------------- |
3373 | -- Enable_Overflow_Check -- | |
3374 | --------------------------- | |
3375 | ||
3376 | procedure Enable_Overflow_Check (N : Node_Id) is | |
3377 | Typ : constant Entity_Id := Base_Type (Etype (N)); | |
3378 | Chk : Nat; | |
3379 | OK : Boolean; | |
3380 | Ent : Entity_Id; | |
3381 | Ofs : Uint; | |
3382 | Lo : Uint; | |
3383 | Hi : Uint; | |
ee6ba406 | 3384 | |
ee6ba406 | 3385 | begin |
9dfe12ae | 3386 | if Debug_Flag_CC then |
3387 | w ("Enable_Overflow_Check for node ", Int (N)); | |
3388 | Write_Str (" Source location = "); | |
3389 | wl (Sloc (N)); | |
00c403ee | 3390 | pg (Union_Id (N)); |
ee6ba406 | 3391 | end if; |
ee6ba406 | 3392 | |
feff2f05 | 3393 | -- Nothing to do if the range of the result is known OK. We skip this |
3394 | -- for conversions, since the caller already did the check, and in any | |
3395 | -- case the condition for deleting the check for a type conversion is | |
cc60bd16 | 3396 | -- different. |
ee6ba406 | 3397 | |
9dfe12ae | 3398 | if Nkind (N) /= N_Type_Conversion then |
3399 | Determine_Range (N, OK, Lo, Hi); | |
ee6ba406 | 3400 | |
cc60bd16 | 3401 | -- Note in the test below that we assume that the range is not OK |
3402 | -- if a bound of the range is equal to that of the type. That's not | |
3403 | -- quite accurate but we do this for the following reasons: | |
ee6ba406 | 3404 | |
9dfe12ae | 3405 | -- a) The way that Determine_Range works, it will typically report |
3406 | -- the bounds of the value as being equal to the bounds of the | |
3407 | -- type, because it either can't tell anything more precise, or | |
3408 | -- does not think it is worth the effort to be more precise. | |
ee6ba406 | 3409 | |
9dfe12ae | 3410 | -- b) It is very unusual to have a situation in which this would |
3411 | -- generate an unnecessary overflow check (an example would be | |
3412 | -- a subtype with a range 0 .. Integer'Last - 1 to which the | |
cc60bd16 | 3413 | -- literal value one is added). |
ee6ba406 | 3414 | |
9dfe12ae | 3415 | -- c) The alternative is a lot of special casing in this routine |
3416 | -- which would partially duplicate Determine_Range processing. | |
ee6ba406 | 3417 | |
9dfe12ae | 3418 | if OK |
3419 | and then Lo > Expr_Value (Type_Low_Bound (Typ)) | |
3420 | and then Hi < Expr_Value (Type_High_Bound (Typ)) | |
3421 | then | |
3422 | if Debug_Flag_CC then | |
3423 | w ("No overflow check required"); | |
3424 | end if; | |
3425 | ||
3426 | return; | |
3427 | end if; | |
3428 | end if; | |
3429 | ||
feff2f05 | 3430 | -- If not in optimizing mode, set flag and we are done. We are also done |
3431 | -- (and just set the flag) if the type is not a discrete type, since it | |
3432 | -- is not worth the effort to eliminate checks for other than discrete | |
3433 | -- types. In addition, we take this same path if we have stored the | |
3434 | -- maximum number of checks possible already (a very unlikely situation, | |
3435 | -- but we do not want to blow up!) | |
9dfe12ae | 3436 | |
3437 | if Optimization_Level = 0 | |
3438 | or else not Is_Discrete_Type (Etype (N)) | |
3439 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 3440 | then |
00c403ee | 3441 | Activate_Overflow_Check (N); |
9dfe12ae | 3442 | |
3443 | if Debug_Flag_CC then | |
3444 | w ("Optimization off"); | |
3445 | end if; | |
3446 | ||
ee6ba406 | 3447 | return; |
9dfe12ae | 3448 | end if; |
ee6ba406 | 3449 | |
9dfe12ae | 3450 | -- Otherwise evaluate and check the expression |
3451 | ||
3452 | Find_Check | |
3453 | (Expr => N, | |
3454 | Check_Type => 'O', | |
3455 | Target_Type => Empty, | |
3456 | Entry_OK => OK, | |
3457 | Check_Num => Chk, | |
3458 | Ent => Ent, | |
3459 | Ofs => Ofs); | |
3460 | ||
3461 | if Debug_Flag_CC then | |
3462 | w ("Called Find_Check"); | |
3463 | w (" OK = ", OK); | |
3464 | ||
3465 | if OK then | |
3466 | w (" Check_Num = ", Chk); | |
3467 | w (" Ent = ", Int (Ent)); | |
3468 | Write_Str (" Ofs = "); | |
3469 | pid (Ofs); | |
3470 | end if; | |
3471 | end if; | |
ee6ba406 | 3472 | |
9dfe12ae | 3473 | -- If check is not of form to optimize, then set flag and we are done |
3474 | ||
3475 | if not OK then | |
00c403ee | 3476 | Activate_Overflow_Check (N); |
ee6ba406 | 3477 | return; |
9dfe12ae | 3478 | end if; |
ee6ba406 | 3479 | |
9dfe12ae | 3480 | -- If check is already performed, then return without setting flag |
3481 | ||
3482 | if Chk /= 0 then | |
3483 | if Debug_Flag_CC then | |
3484 | w ("Check suppressed!"); | |
3485 | end if; | |
ee6ba406 | 3486 | |
ee6ba406 | 3487 | return; |
9dfe12ae | 3488 | end if; |
ee6ba406 | 3489 | |
9dfe12ae | 3490 | -- Here we will make a new entry for the new check |
3491 | ||
00c403ee | 3492 | Activate_Overflow_Check (N); |
9dfe12ae | 3493 | Num_Saved_Checks := Num_Saved_Checks + 1; |
3494 | Saved_Checks (Num_Saved_Checks) := | |
3495 | (Killed => False, | |
3496 | Entity => Ent, | |
3497 | Offset => Ofs, | |
3498 | Check_Type => 'O', | |
3499 | Target_Type => Empty); | |
3500 | ||
3501 | if Debug_Flag_CC then | |
3502 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
3503 | w (" Entity = ", Int (Ent)); | |
3504 | Write_Str (" Offset = "); | |
3505 | pid (Ofs); | |
3506 | w (" Check_Type = O"); | |
3507 | w (" Target_Type = Empty"); | |
3508 | end if; | |
ee6ba406 | 3509 | |
feff2f05 | 3510 | -- If we get an exception, then something went wrong, probably because of |
3511 | -- an error in the structure of the tree due to an incorrect program. Or it | |
3512 | -- may be a bug in the optimization circuit. In either case the safest | |
3513 | -- thing is simply to set the check flag unconditionally. | |
9dfe12ae | 3514 | |
3515 | exception | |
3516 | when others => | |
00c403ee | 3517 | Activate_Overflow_Check (N); |
9dfe12ae | 3518 | |
3519 | if Debug_Flag_CC then | |
3520 | w (" exception occurred, overflow flag set"); | |
3521 | end if; | |
3522 | ||
3523 | return; | |
3524 | end Enable_Overflow_Check; | |
3525 | ||
3526 | ------------------------ | |
3527 | -- Enable_Range_Check -- | |
3528 | ------------------------ | |
3529 | ||
3530 | procedure Enable_Range_Check (N : Node_Id) is | |
3531 | Chk : Nat; | |
3532 | OK : Boolean; | |
3533 | Ent : Entity_Id; | |
3534 | Ofs : Uint; | |
3535 | Ttyp : Entity_Id; | |
3536 | P : Node_Id; | |
3537 | ||
3538 | begin | |
feff2f05 | 3539 | -- Return if unchecked type conversion with range check killed. In this |
3540 | -- case we never set the flag (that's what Kill_Range_Check is about!) | |
9dfe12ae | 3541 | |
3542 | if Nkind (N) = N_Unchecked_Type_Conversion | |
3543 | and then Kill_Range_Check (N) | |
ee6ba406 | 3544 | then |
3545 | return; | |
9dfe12ae | 3546 | end if; |
ee6ba406 | 3547 | |
0577b0b1 | 3548 | -- Check for various cases where we should suppress the range check |
3549 | ||
3550 | -- No check if range checks suppressed for type of node | |
3551 | ||
3552 | if Present (Etype (N)) | |
3553 | and then Range_Checks_Suppressed (Etype (N)) | |
3554 | then | |
3555 | return; | |
3556 | ||
3557 | -- No check if node is an entity name, and range checks are suppressed | |
3558 | -- for this entity, or for the type of this entity. | |
3559 | ||
3560 | elsif Is_Entity_Name (N) | |
3561 | and then (Range_Checks_Suppressed (Entity (N)) | |
3562 | or else Range_Checks_Suppressed (Etype (Entity (N)))) | |
3563 | then | |
3564 | return; | |
3565 | ||
3566 | -- No checks if index of array, and index checks are suppressed for | |
3567 | -- the array object or the type of the array. | |
3568 | ||
3569 | elsif Nkind (Parent (N)) = N_Indexed_Component then | |
3570 | declare | |
3571 | Pref : constant Node_Id := Prefix (Parent (N)); | |
3572 | begin | |
3573 | if Is_Entity_Name (Pref) | |
3574 | and then Index_Checks_Suppressed (Entity (Pref)) | |
3575 | then | |
3576 | return; | |
3577 | elsif Index_Checks_Suppressed (Etype (Pref)) then | |
3578 | return; | |
3579 | end if; | |
3580 | end; | |
3581 | end if; | |
3582 | ||
9dfe12ae | 3583 | -- Debug trace output |
ee6ba406 | 3584 | |
9dfe12ae | 3585 | if Debug_Flag_CC then |
3586 | w ("Enable_Range_Check for node ", Int (N)); | |
3587 | Write_Str (" Source location = "); | |
3588 | wl (Sloc (N)); | |
00c403ee | 3589 | pg (Union_Id (N)); |
9dfe12ae | 3590 | end if; |
3591 | ||
feff2f05 | 3592 | -- If not in optimizing mode, set flag and we are done. We are also done |
3593 | -- (and just set the flag) if the type is not a discrete type, since it | |
3594 | -- is not worth the effort to eliminate checks for other than discrete | |
3595 | -- types. In addition, we take this same path if we have stored the | |
3596 | -- maximum number of checks possible already (a very unlikely situation, | |
3597 | -- but we do not want to blow up!) | |
9dfe12ae | 3598 | |
3599 | if Optimization_Level = 0 | |
3600 | or else No (Etype (N)) | |
3601 | or else not Is_Discrete_Type (Etype (N)) | |
3602 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 3603 | then |
00c403ee | 3604 | Activate_Range_Check (N); |
9dfe12ae | 3605 | |
3606 | if Debug_Flag_CC then | |
3607 | w ("Optimization off"); | |
3608 | end if; | |
3609 | ||
ee6ba406 | 3610 | return; |
9dfe12ae | 3611 | end if; |
ee6ba406 | 3612 | |
9dfe12ae | 3613 | -- Otherwise find out the target type |
ee6ba406 | 3614 | |
9dfe12ae | 3615 | P := Parent (N); |
ee6ba406 | 3616 | |
9dfe12ae | 3617 | -- For assignment, use left side subtype |
3618 | ||
3619 | if Nkind (P) = N_Assignment_Statement | |
3620 | and then Expression (P) = N | |
3621 | then | |
3622 | Ttyp := Etype (Name (P)); | |
3623 | ||
3624 | -- For indexed component, use subscript subtype | |
3625 | ||
3626 | elsif Nkind (P) = N_Indexed_Component then | |
3627 | declare | |
3628 | Atyp : Entity_Id; | |
3629 | Indx : Node_Id; | |
3630 | Subs : Node_Id; | |
3631 | ||
3632 | begin | |
3633 | Atyp := Etype (Prefix (P)); | |
3634 | ||
3635 | if Is_Access_Type (Atyp) then | |
3636 | Atyp := Designated_Type (Atyp); | |
f07ea091 | 3637 | |
3638 | -- If the prefix is an access to an unconstrained array, | |
feff2f05 | 3639 | -- perform check unconditionally: it depends on the bounds of |
3640 | -- an object and we cannot currently recognize whether the test | |
3641 | -- may be redundant. | |
f07ea091 | 3642 | |
3643 | if not Is_Constrained (Atyp) then | |
00c403ee | 3644 | Activate_Range_Check (N); |
f07ea091 | 3645 | return; |
3646 | end if; | |
7189d17f | 3647 | |
feff2f05 | 3648 | -- Ditto if the prefix is an explicit dereference whose designated |
3649 | -- type is unconstrained. | |
7189d17f | 3650 | |
3651 | elsif Nkind (Prefix (P)) = N_Explicit_Dereference | |
3652 | and then not Is_Constrained (Atyp) | |
3653 | then | |
00c403ee | 3654 | Activate_Range_Check (N); |
7189d17f | 3655 | return; |
9dfe12ae | 3656 | end if; |
3657 | ||
3658 | Indx := First_Index (Atyp); | |
3659 | Subs := First (Expressions (P)); | |
3660 | loop | |
3661 | if Subs = N then | |
3662 | Ttyp := Etype (Indx); | |
3663 | exit; | |
3664 | end if; | |
3665 | ||
3666 | Next_Index (Indx); | |
3667 | Next (Subs); | |
3668 | end loop; | |
3669 | end; | |
3670 | ||
3671 | -- For now, ignore all other cases, they are not so interesting | |
3672 | ||
3673 | else | |
3674 | if Debug_Flag_CC then | |
3675 | w (" target type not found, flag set"); | |
3676 | end if; | |
3677 | ||
00c403ee | 3678 | Activate_Range_Check (N); |
9dfe12ae | 3679 | return; |
3680 | end if; | |
3681 | ||
3682 | -- Evaluate and check the expression | |
3683 | ||
3684 | Find_Check | |
3685 | (Expr => N, | |
3686 | Check_Type => 'R', | |
3687 | Target_Type => Ttyp, | |
3688 | Entry_OK => OK, | |
3689 | Check_Num => Chk, | |
3690 | Ent => Ent, | |
3691 | Ofs => Ofs); | |
3692 | ||
3693 | if Debug_Flag_CC then | |
3694 | w ("Called Find_Check"); | |
3695 | w ("Target_Typ = ", Int (Ttyp)); | |
3696 | w (" OK = ", OK); | |
3697 | ||
3698 | if OK then | |
3699 | w (" Check_Num = ", Chk); | |
3700 | w (" Ent = ", Int (Ent)); | |
3701 | Write_Str (" Ofs = "); | |
3702 | pid (Ofs); | |
3703 | end if; | |
3704 | end if; | |
3705 | ||
3706 | -- If check is not of form to optimize, then set flag and we are done | |
3707 | ||
3708 | if not OK then | |
3709 | if Debug_Flag_CC then | |
3710 | w (" expression not of optimizable type, flag set"); | |
3711 | end if; | |
3712 | ||
00c403ee | 3713 | Activate_Range_Check (N); |
9dfe12ae | 3714 | return; |
3715 | end if; | |
3716 | ||
3717 | -- If check is already performed, then return without setting flag | |
3718 | ||
3719 | if Chk /= 0 then | |
3720 | if Debug_Flag_CC then | |
3721 | w ("Check suppressed!"); | |
3722 | end if; | |
3723 | ||
3724 | return; | |
3725 | end if; | |
3726 | ||
3727 | -- Here we will make a new entry for the new check | |
3728 | ||
00c403ee | 3729 | Activate_Range_Check (N); |
9dfe12ae | 3730 | Num_Saved_Checks := Num_Saved_Checks + 1; |
3731 | Saved_Checks (Num_Saved_Checks) := | |
3732 | (Killed => False, | |
3733 | Entity => Ent, | |
3734 | Offset => Ofs, | |
3735 | Check_Type => 'R', | |
3736 | Target_Type => Ttyp); | |
3737 | ||
3738 | if Debug_Flag_CC then | |
3739 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
3740 | w (" Entity = ", Int (Ent)); | |
3741 | Write_Str (" Offset = "); | |
3742 | pid (Ofs); | |
3743 | w (" Check_Type = R"); | |
3744 | w (" Target_Type = ", Int (Ttyp)); | |
00c403ee | 3745 | pg (Union_Id (Ttyp)); |
9dfe12ae | 3746 | end if; |
3747 | ||
feff2f05 | 3748 | -- If we get an exception, then something went wrong, probably because of |
3749 | -- an error in the structure of the tree due to an incorrect program. Or | |
3750 | -- it may be a bug in the optimization circuit. In either case the safest | |
3751 | -- thing is simply to set the check flag unconditionally. | |
9dfe12ae | 3752 | |
3753 | exception | |
3754 | when others => | |
00c403ee | 3755 | Activate_Range_Check (N); |
9dfe12ae | 3756 | |
3757 | if Debug_Flag_CC then | |
3758 | w (" exception occurred, range flag set"); | |
3759 | end if; | |
3760 | ||
3761 | return; | |
3762 | end Enable_Range_Check; | |
3763 | ||
3764 | ------------------ | |
3765 | -- Ensure_Valid -- | |
3766 | ------------------ | |
3767 | ||
3768 | procedure Ensure_Valid (Expr : Node_Id; Holes_OK : Boolean := False) is | |
3769 | Typ : constant Entity_Id := Etype (Expr); | |
3770 | ||
3771 | begin | |
3772 | -- Ignore call if we are not doing any validity checking | |
3773 | ||
3774 | if not Validity_Checks_On then | |
3775 | return; | |
3776 | ||
0577b0b1 | 3777 | -- Ignore call if range or validity checks suppressed on entity or type |
9dfe12ae | 3778 | |
0577b0b1 | 3779 | elsif Range_Or_Validity_Checks_Suppressed (Expr) then |
9dfe12ae | 3780 | return; |
3781 | ||
feff2f05 | 3782 | -- No check required if expression is from the expander, we assume the |
3783 | -- expander will generate whatever checks are needed. Note that this is | |
3784 | -- not just an optimization, it avoids infinite recursions! | |
9dfe12ae | 3785 | |
3786 | -- Unchecked conversions must be checked, unless they are initialized | |
3787 | -- scalar values, as in a component assignment in an init proc. | |
3788 | ||
3789 | -- In addition, we force a check if Force_Validity_Checks is set | |
3790 | ||
3791 | elsif not Comes_From_Source (Expr) | |
3792 | and then not Force_Validity_Checks | |
3793 | and then (Nkind (Expr) /= N_Unchecked_Type_Conversion | |
3794 | or else Kill_Range_Check (Expr)) | |
3795 | then | |
3796 | return; | |
3797 | ||
3798 | -- No check required if expression is known to have valid value | |
3799 | ||
3800 | elsif Expr_Known_Valid (Expr) then | |
3801 | return; | |
3802 | ||
feff2f05 | 3803 | -- Ignore case of enumeration with holes where the flag is set not to |
3804 | -- worry about holes, since no special validity check is needed | |
9dfe12ae | 3805 | |
3806 | elsif Is_Enumeration_Type (Typ) | |
3807 | and then Has_Non_Standard_Rep (Typ) | |
3808 | and then Holes_OK | |
3809 | then | |
3810 | return; | |
3811 | ||
f2a06be9 | 3812 | -- No check required on the left-hand side of an assignment |
9dfe12ae | 3813 | |
3814 | elsif Nkind (Parent (Expr)) = N_Assignment_Statement | |
3815 | and then Expr = Name (Parent (Expr)) | |
3816 | then | |
3817 | return; | |
3818 | ||
38f5559f | 3819 | -- No check on a univeral real constant. The context will eventually |
3820 | -- convert it to a machine number for some target type, or report an | |
3821 | -- illegality. | |
3822 | ||
3823 | elsif Nkind (Expr) = N_Real_Literal | |
3824 | and then Etype (Expr) = Universal_Real | |
3825 | then | |
3826 | return; | |
3827 | ||
0577b0b1 | 3828 | -- If the expression denotes a component of a packed boolean arrray, |
3829 | -- no possible check applies. We ignore the old ACATS chestnuts that | |
3830 | -- involve Boolean range True..True. | |
3831 | ||
3832 | -- Note: validity checks are generated for expressions that yield a | |
3833 | -- scalar type, when it is possible to create a value that is outside of | |
3834 | -- the type. If this is a one-bit boolean no such value exists. This is | |
3835 | -- an optimization, and it also prevents compiler blowing up during the | |
3836 | -- elaboration of improperly expanded packed array references. | |
3837 | ||
3838 | elsif Nkind (Expr) = N_Indexed_Component | |
3839 | and then Is_Bit_Packed_Array (Etype (Prefix (Expr))) | |
3840 | and then Root_Type (Etype (Expr)) = Standard_Boolean | |
3841 | then | |
3842 | return; | |
3843 | ||
9dfe12ae | 3844 | -- An annoying special case. If this is an out parameter of a scalar |
3845 | -- type, then the value is not going to be accessed, therefore it is | |
3846 | -- inappropriate to do any validity check at the call site. | |
3847 | ||
3848 | else | |
3849 | -- Only need to worry about scalar types | |
3850 | ||
3851 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 3852 | declare |
3853 | P : Node_Id; | |
3854 | N : Node_Id; | |
3855 | E : Entity_Id; | |
3856 | F : Entity_Id; | |
3857 | A : Node_Id; | |
3858 | L : List_Id; | |
3859 | ||
3860 | begin | |
3861 | -- Find actual argument (which may be a parameter association) | |
3862 | -- and the parent of the actual argument (the call statement) | |
3863 | ||
3864 | N := Expr; | |
3865 | P := Parent (Expr); | |
3866 | ||
3867 | if Nkind (P) = N_Parameter_Association then | |
3868 | N := P; | |
3869 | P := Parent (N); | |
3870 | end if; | |
3871 | ||
feff2f05 | 3872 | -- Only need to worry if we are argument of a procedure call |
3873 | -- since functions don't have out parameters. If this is an | |
3874 | -- indirect or dispatching call, get signature from the | |
3875 | -- subprogram type. | |
ee6ba406 | 3876 | |
3877 | if Nkind (P) = N_Procedure_Call_Statement then | |
3878 | L := Parameter_Associations (P); | |
9dfe12ae | 3879 | |
3880 | if Is_Entity_Name (Name (P)) then | |
3881 | E := Entity (Name (P)); | |
3882 | else | |
3883 | pragma Assert (Nkind (Name (P)) = N_Explicit_Dereference); | |
3884 | E := Etype (Name (P)); | |
3885 | end if; | |
ee6ba406 | 3886 | |
feff2f05 | 3887 | -- Only need to worry if there are indeed actuals, and if |
3888 | -- this could be a procedure call, otherwise we cannot get a | |
3889 | -- match (either we are not an argument, or the mode of the | |
3890 | -- formal is not OUT). This test also filters out the | |
3891 | -- generic case. | |
ee6ba406 | 3892 | |
3893 | if Is_Non_Empty_List (L) | |
3894 | and then Is_Subprogram (E) | |
3895 | then | |
feff2f05 | 3896 | -- This is the loop through parameters, looking for an |
3897 | -- OUT parameter for which we are the argument. | |
ee6ba406 | 3898 | |
3899 | F := First_Formal (E); | |
3900 | A := First (L); | |
ee6ba406 | 3901 | while Present (F) loop |
3902 | if Ekind (F) = E_Out_Parameter and then A = N then | |
3903 | return; | |
3904 | end if; | |
3905 | ||
3906 | Next_Formal (F); | |
3907 | Next (A); | |
3908 | end loop; | |
3909 | end if; | |
3910 | end if; | |
3911 | end; | |
3912 | end if; | |
3913 | end if; | |
3914 | ||
0577b0b1 | 3915 | -- If we fall through, a validity check is required |
ee6ba406 | 3916 | |
3917 | Insert_Valid_Check (Expr); | |
ce7498d3 | 3918 | |
3919 | if Is_Entity_Name (Expr) | |
3920 | and then Safe_To_Capture_Value (Expr, Entity (Expr)) | |
3921 | then | |
3922 | Set_Is_Known_Valid (Entity (Expr)); | |
3923 | end if; | |
ee6ba406 | 3924 | end Ensure_Valid; |
3925 | ||
3926 | ---------------------- | |
3927 | -- Expr_Known_Valid -- | |
3928 | ---------------------- | |
3929 | ||
3930 | function Expr_Known_Valid (Expr : Node_Id) return Boolean is | |
3931 | Typ : constant Entity_Id := Etype (Expr); | |
3932 | ||
3933 | begin | |
feff2f05 | 3934 | -- Non-scalar types are always considered valid, since they never give |
3935 | -- rise to the issues of erroneous or bounded error behavior that are | |
3936 | -- the concern. In formal reference manual terms the notion of validity | |
3937 | -- only applies to scalar types. Note that even when packed arrays are | |
3938 | -- represented using modular types, they are still arrays semantically, | |
3939 | -- so they are also always valid (in particular, the unused bits can be | |
3940 | -- random rubbish without affecting the validity of the array value). | |
ee6ba406 | 3941 | |
fa814356 | 3942 | if not Is_Scalar_Type (Typ) or else Is_Packed_Array_Type (Typ) then |
ee6ba406 | 3943 | return True; |
3944 | ||
3945 | -- If no validity checking, then everything is considered valid | |
3946 | ||
3947 | elsif not Validity_Checks_On then | |
3948 | return True; | |
3949 | ||
3950 | -- Floating-point types are considered valid unless floating-point | |
3951 | -- validity checks have been specifically turned on. | |
3952 | ||
3953 | elsif Is_Floating_Point_Type (Typ) | |
3954 | and then not Validity_Check_Floating_Point | |
3955 | then | |
3956 | return True; | |
3957 | ||
feff2f05 | 3958 | -- If the expression is the value of an object that is known to be |
3959 | -- valid, then clearly the expression value itself is valid. | |
ee6ba406 | 3960 | |
3961 | elsif Is_Entity_Name (Expr) | |
3962 | and then Is_Known_Valid (Entity (Expr)) | |
3963 | then | |
3964 | return True; | |
3965 | ||
0577b0b1 | 3966 | -- References to discriminants are always considered valid. The value |
3967 | -- of a discriminant gets checked when the object is built. Within the | |
3968 | -- record, we consider it valid, and it is important to do so, since | |
3969 | -- otherwise we can try to generate bogus validity checks which | |
feff2f05 | 3970 | -- reference discriminants out of scope. Discriminants of concurrent |
3971 | -- types are excluded for the same reason. | |
0577b0b1 | 3972 | |
3973 | elsif Is_Entity_Name (Expr) | |
feff2f05 | 3974 | and then Denotes_Discriminant (Expr, Check_Concurrent => True) |
0577b0b1 | 3975 | then |
3976 | return True; | |
3977 | ||
feff2f05 | 3978 | -- If the type is one for which all values are known valid, then we are |
3979 | -- sure that the value is valid except in the slightly odd case where | |
3980 | -- the expression is a reference to a variable whose size has been | |
3981 | -- explicitly set to a value greater than the object size. | |
ee6ba406 | 3982 | |
3983 | elsif Is_Known_Valid (Typ) then | |
3984 | if Is_Entity_Name (Expr) | |
3985 | and then Ekind (Entity (Expr)) = E_Variable | |
3986 | and then Esize (Entity (Expr)) > Esize (Typ) | |
3987 | then | |
3988 | return False; | |
3989 | else | |
3990 | return True; | |
3991 | end if; | |
3992 | ||
3993 | -- Integer and character literals always have valid values, where | |
3994 | -- appropriate these will be range checked in any case. | |
3995 | ||
3996 | elsif Nkind (Expr) = N_Integer_Literal | |
3997 | or else | |
3998 | Nkind (Expr) = N_Character_Literal | |
3999 | then | |
4000 | return True; | |
4001 | ||
4002 | -- If we have a type conversion or a qualification of a known valid | |
4003 | -- value, then the result will always be valid. | |
4004 | ||
4005 | elsif Nkind (Expr) = N_Type_Conversion | |
4006 | or else | |
4007 | Nkind (Expr) = N_Qualified_Expression | |
4008 | then | |
4009 | return Expr_Known_Valid (Expression (Expr)); | |
4010 | ||
38f5559f | 4011 | -- The result of any operator is always considered valid, since we |
4012 | -- assume the necessary checks are done by the operator. For operators | |
4013 | -- on floating-point operations, we must also check when the operation | |
4014 | -- is the right-hand side of an assignment, or is an actual in a call. | |
ee6ba406 | 4015 | |
0577b0b1 | 4016 | elsif Nkind (Expr) in N_Op then |
1d90d657 | 4017 | if Is_Floating_Point_Type (Typ) |
4018 | and then Validity_Check_Floating_Point | |
4019 | and then | |
4020 | (Nkind (Parent (Expr)) = N_Assignment_Statement | |
4021 | or else Nkind (Parent (Expr)) = N_Function_Call | |
4022 | or else Nkind (Parent (Expr)) = N_Parameter_Association) | |
4023 | then | |
4024 | return False; | |
4025 | else | |
4026 | return True; | |
4027 | end if; | |
4028 | ||
feff2f05 | 4029 | -- The result of a membership test is always valid, since it is true or |
4030 | -- false, there are no other possibilities. | |
0577b0b1 | 4031 | |
4032 | elsif Nkind (Expr) in N_Membership_Test then | |
4033 | return True; | |
4034 | ||
ee6ba406 | 4035 | -- For all other cases, we do not know the expression is valid |
4036 | ||
4037 | else | |
4038 | return False; | |
4039 | end if; | |
4040 | end Expr_Known_Valid; | |
4041 | ||
9dfe12ae | 4042 | ---------------- |
4043 | -- Find_Check -- | |
4044 | ---------------- | |
4045 | ||
4046 | procedure Find_Check | |
4047 | (Expr : Node_Id; | |
4048 | Check_Type : Character; | |
4049 | Target_Type : Entity_Id; | |
4050 | Entry_OK : out Boolean; | |
4051 | Check_Num : out Nat; | |
4052 | Ent : out Entity_Id; | |
4053 | Ofs : out Uint) | |
4054 | is | |
4055 | function Within_Range_Of | |
4056 | (Target_Type : Entity_Id; | |
314a23b6 | 4057 | Check_Type : Entity_Id) return Boolean; |
9dfe12ae | 4058 | -- Given a requirement for checking a range against Target_Type, and |
4059 | -- and a range Check_Type against which a check has already been made, | |
4060 | -- determines if the check against check type is sufficient to ensure | |
4061 | -- that no check against Target_Type is required. | |
4062 | ||
4063 | --------------------- | |
4064 | -- Within_Range_Of -- | |
4065 | --------------------- | |
4066 | ||
4067 | function Within_Range_Of | |
4068 | (Target_Type : Entity_Id; | |
314a23b6 | 4069 | Check_Type : Entity_Id) return Boolean |
9dfe12ae | 4070 | is |
4071 | begin | |
4072 | if Target_Type = Check_Type then | |
4073 | return True; | |
4074 | ||
4075 | else | |
4076 | declare | |
4077 | Tlo : constant Node_Id := Type_Low_Bound (Target_Type); | |
4078 | Thi : constant Node_Id := Type_High_Bound (Target_Type); | |
4079 | Clo : constant Node_Id := Type_Low_Bound (Check_Type); | |
4080 | Chi : constant Node_Id := Type_High_Bound (Check_Type); | |
4081 | ||
4082 | begin | |
4083 | if (Tlo = Clo | |
4084 | or else (Compile_Time_Known_Value (Tlo) | |
4085 | and then | |
4086 | Compile_Time_Known_Value (Clo) | |
4087 | and then | |
4088 | Expr_Value (Clo) >= Expr_Value (Tlo))) | |
4089 | and then | |
4090 | (Thi = Chi | |
4091 | or else (Compile_Time_Known_Value (Thi) | |
4092 | and then | |
4093 | Compile_Time_Known_Value (Chi) | |
4094 | and then | |
4095 | Expr_Value (Chi) <= Expr_Value (Clo))) | |
4096 | then | |
4097 | return True; | |
4098 | else | |
4099 | return False; | |
4100 | end if; | |
4101 | end; | |
4102 | end if; | |
4103 | end Within_Range_Of; | |
4104 | ||
4105 | -- Start of processing for Find_Check | |
4106 | ||
4107 | begin | |
f2a06be9 | 4108 | -- Establish default, to avoid warnings from GCC |
9dfe12ae | 4109 | |
4110 | Check_Num := 0; | |
4111 | ||
4112 | -- Case of expression is simple entity reference | |
4113 | ||
4114 | if Is_Entity_Name (Expr) then | |
4115 | Ent := Entity (Expr); | |
4116 | Ofs := Uint_0; | |
4117 | ||
4118 | -- Case of expression is entity + known constant | |
4119 | ||
4120 | elsif Nkind (Expr) = N_Op_Add | |
4121 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
4122 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
4123 | then | |
4124 | Ent := Entity (Left_Opnd (Expr)); | |
4125 | Ofs := Expr_Value (Right_Opnd (Expr)); | |
4126 | ||
4127 | -- Case of expression is entity - known constant | |
4128 | ||
4129 | elsif Nkind (Expr) = N_Op_Subtract | |
4130 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
4131 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
4132 | then | |
4133 | Ent := Entity (Left_Opnd (Expr)); | |
4134 | Ofs := UI_Negate (Expr_Value (Right_Opnd (Expr))); | |
4135 | ||
4136 | -- Any other expression is not of the right form | |
4137 | ||
4138 | else | |
4139 | Ent := Empty; | |
4140 | Ofs := Uint_0; | |
4141 | Entry_OK := False; | |
4142 | return; | |
4143 | end if; | |
4144 | ||
feff2f05 | 4145 | -- Come here with expression of appropriate form, check if entity is an |
4146 | -- appropriate one for our purposes. | |
9dfe12ae | 4147 | |
4148 | if (Ekind (Ent) = E_Variable | |
cc60bd16 | 4149 | or else Is_Constant_Object (Ent)) |
9dfe12ae | 4150 | and then not Is_Library_Level_Entity (Ent) |
4151 | then | |
4152 | Entry_OK := True; | |
4153 | else | |
4154 | Entry_OK := False; | |
4155 | return; | |
4156 | end if; | |
4157 | ||
4158 | -- See if there is matching check already | |
4159 | ||
4160 | for J in reverse 1 .. Num_Saved_Checks loop | |
4161 | declare | |
4162 | SC : Saved_Check renames Saved_Checks (J); | |
4163 | ||
4164 | begin | |
4165 | if SC.Killed = False | |
4166 | and then SC.Entity = Ent | |
4167 | and then SC.Offset = Ofs | |
4168 | and then SC.Check_Type = Check_Type | |
4169 | and then Within_Range_Of (Target_Type, SC.Target_Type) | |
4170 | then | |
4171 | Check_Num := J; | |
4172 | return; | |
4173 | end if; | |
4174 | end; | |
4175 | end loop; | |
4176 | ||
4177 | -- If we fall through entry was not found | |
4178 | ||
4179 | Check_Num := 0; | |
4180 | return; | |
4181 | end Find_Check; | |
4182 | ||
4183 | --------------------------------- | |
4184 | -- Generate_Discriminant_Check -- | |
4185 | --------------------------------- | |
4186 | ||
4187 | -- Note: the code for this procedure is derived from the | |
feff2f05 | 4188 | -- Emit_Discriminant_Check Routine in trans.c. |
9dfe12ae | 4189 | |
4190 | procedure Generate_Discriminant_Check (N : Node_Id) is | |
4191 | Loc : constant Source_Ptr := Sloc (N); | |
4192 | Pref : constant Node_Id := Prefix (N); | |
4193 | Sel : constant Node_Id := Selector_Name (N); | |
4194 | ||
4195 | Orig_Comp : constant Entity_Id := | |
4196 | Original_Record_Component (Entity (Sel)); | |
4197 | -- The original component to be checked | |
4198 | ||
4199 | Discr_Fct : constant Entity_Id := | |
4200 | Discriminant_Checking_Func (Orig_Comp); | |
4201 | -- The discriminant checking function | |
4202 | ||
4203 | Discr : Entity_Id; | |
4204 | -- One discriminant to be checked in the type | |
4205 | ||
4206 | Real_Discr : Entity_Id; | |
4207 | -- Actual discriminant in the call | |
4208 | ||
4209 | Pref_Type : Entity_Id; | |
4210 | -- Type of relevant prefix (ignoring private/access stuff) | |
4211 | ||
4212 | Args : List_Id; | |
4213 | -- List of arguments for function call | |
4214 | ||
4215 | Formal : Entity_Id; | |
feff2f05 | 4216 | -- Keep track of the formal corresponding to the actual we build for |
4217 | -- each discriminant, in order to be able to perform the necessary type | |
4218 | -- conversions. | |
9dfe12ae | 4219 | |
4220 | Scomp : Node_Id; | |
4221 | -- Selected component reference for checking function argument | |
4222 | ||
4223 | begin | |
4224 | Pref_Type := Etype (Pref); | |
4225 | ||
4226 | -- Force evaluation of the prefix, so that it does not get evaluated | |
4227 | -- twice (once for the check, once for the actual reference). Such a | |
4228 | -- double evaluation is always a potential source of inefficiency, | |
4229 | -- and is functionally incorrect in the volatile case, or when the | |
4230 | -- prefix may have side-effects. An entity or a component of an | |
4231 | -- entity requires no evaluation. | |
4232 | ||
4233 | if Is_Entity_Name (Pref) then | |
4234 | if Treat_As_Volatile (Entity (Pref)) then | |
4235 | Force_Evaluation (Pref, Name_Req => True); | |
4236 | end if; | |
4237 | ||
4238 | elsif Treat_As_Volatile (Etype (Pref)) then | |
4239 | Force_Evaluation (Pref, Name_Req => True); | |
4240 | ||
4241 | elsif Nkind (Pref) = N_Selected_Component | |
4242 | and then Is_Entity_Name (Prefix (Pref)) | |
4243 | then | |
4244 | null; | |
4245 | ||
4246 | else | |
4247 | Force_Evaluation (Pref, Name_Req => True); | |
4248 | end if; | |
4249 | ||
4250 | -- For a tagged type, use the scope of the original component to | |
4251 | -- obtain the type, because ??? | |
4252 | ||
4253 | if Is_Tagged_Type (Scope (Orig_Comp)) then | |
4254 | Pref_Type := Scope (Orig_Comp); | |
4255 | ||
feff2f05 | 4256 | -- For an untagged derived type, use the discriminants of the parent |
4257 | -- which have been renamed in the derivation, possibly by a one-to-many | |
4258 | -- discriminant constraint. For non-tagged type, initially get the Etype | |
4259 | -- of the prefix | |
9dfe12ae | 4260 | |
4261 | else | |
4262 | if Is_Derived_Type (Pref_Type) | |
4263 | and then Number_Discriminants (Pref_Type) /= | |
4264 | Number_Discriminants (Etype (Base_Type (Pref_Type))) | |
4265 | then | |
4266 | Pref_Type := Etype (Base_Type (Pref_Type)); | |
4267 | end if; | |
4268 | end if; | |
4269 | ||
4270 | -- We definitely should have a checking function, This routine should | |
4271 | -- not be called if no discriminant checking function is present. | |
4272 | ||
4273 | pragma Assert (Present (Discr_Fct)); | |
4274 | ||
4275 | -- Create the list of the actual parameters for the call. This list | |
4276 | -- is the list of the discriminant fields of the record expression to | |
4277 | -- be discriminant checked. | |
4278 | ||
4279 | Args := New_List; | |
4280 | Formal := First_Formal (Discr_Fct); | |
4281 | Discr := First_Discriminant (Pref_Type); | |
4282 | while Present (Discr) loop | |
4283 | ||
4284 | -- If we have a corresponding discriminant field, and a parent | |
4285 | -- subtype is present, then we want to use the corresponding | |
4286 | -- discriminant since this is the one with the useful value. | |
4287 | ||
4288 | if Present (Corresponding_Discriminant (Discr)) | |
4289 | and then Ekind (Pref_Type) = E_Record_Type | |
4290 | and then Present (Parent_Subtype (Pref_Type)) | |
4291 | then | |
4292 | Real_Discr := Corresponding_Discriminant (Discr); | |
4293 | else | |
4294 | Real_Discr := Discr; | |
4295 | end if; | |
4296 | ||
4297 | -- Construct the reference to the discriminant | |
4298 | ||
4299 | Scomp := | |
4300 | Make_Selected_Component (Loc, | |
4301 | Prefix => | |
4302 | Unchecked_Convert_To (Pref_Type, | |
4303 | Duplicate_Subexpr (Pref)), | |
4304 | Selector_Name => New_Occurrence_Of (Real_Discr, Loc)); | |
4305 | ||
4306 | -- Manually analyze and resolve this selected component. We really | |
4307 | -- want it just as it appears above, and do not want the expander | |
feff2f05 | 4308 | -- playing discriminal games etc with this reference. Then we append |
4309 | -- the argument to the list we are gathering. | |
9dfe12ae | 4310 | |
4311 | Set_Etype (Scomp, Etype (Real_Discr)); | |
4312 | Set_Analyzed (Scomp, True); | |
4313 | Append_To (Args, Convert_To (Etype (Formal), Scomp)); | |
4314 | ||
4315 | Next_Formal_With_Extras (Formal); | |
4316 | Next_Discriminant (Discr); | |
4317 | end loop; | |
4318 | ||
4319 | -- Now build and insert the call | |
4320 | ||
4321 | Insert_Action (N, | |
4322 | Make_Raise_Constraint_Error (Loc, | |
4323 | Condition => | |
4324 | Make_Function_Call (Loc, | |
4325 | Name => New_Occurrence_Of (Discr_Fct, Loc), | |
4326 | Parameter_Associations => Args), | |
4327 | Reason => CE_Discriminant_Check_Failed)); | |
4328 | end Generate_Discriminant_Check; | |
4329 | ||
5c99c290 | 4330 | --------------------------- |
4331 | -- Generate_Index_Checks -- | |
4332 | --------------------------- | |
9dfe12ae | 4333 | |
4334 | procedure Generate_Index_Checks (N : Node_Id) is | |
4335 | Loc : constant Source_Ptr := Sloc (N); | |
4336 | A : constant Node_Id := Prefix (N); | |
4337 | Sub : Node_Id; | |
4338 | Ind : Nat; | |
4339 | Num : List_Id; | |
4340 | ||
4341 | begin | |
0577b0b1 | 4342 | -- Ignore call if index checks suppressed for array object or type |
4343 | ||
4344 | if (Is_Entity_Name (A) and then Index_Checks_Suppressed (Entity (A))) | |
4345 | or else Index_Checks_Suppressed (Etype (A)) | |
4346 | then | |
4347 | return; | |
4348 | end if; | |
4349 | ||
4350 | -- Generate the checks | |
4351 | ||
9dfe12ae | 4352 | Sub := First (Expressions (N)); |
4353 | Ind := 1; | |
4354 | while Present (Sub) loop | |
4355 | if Do_Range_Check (Sub) then | |
4356 | Set_Do_Range_Check (Sub, False); | |
4357 | ||
feff2f05 | 4358 | -- Force evaluation except for the case of a simple name of a |
4359 | -- non-volatile entity. | |
9dfe12ae | 4360 | |
4361 | if not Is_Entity_Name (Sub) | |
4362 | or else Treat_As_Volatile (Entity (Sub)) | |
4363 | then | |
4364 | Force_Evaluation (Sub); | |
4365 | end if; | |
4366 | ||
4367 | -- Generate a raise of constraint error with the appropriate | |
4368 | -- reason and a condition of the form: | |
4369 | ||
4370 | -- Base_Type(Sub) not in array'range (subscript) | |
4371 | ||
feff2f05 | 4372 | -- Note that the reason we generate the conversion to the base |
4373 | -- type here is that we definitely want the range check to take | |
4374 | -- place, even if it looks like the subtype is OK. Optimization | |
4375 | -- considerations that allow us to omit the check have already | |
4376 | -- been taken into account in the setting of the Do_Range_Check | |
4377 | -- flag earlier on. | |
9dfe12ae | 4378 | |
4379 | if Ind = 1 then | |
4380 | Num := No_List; | |
4381 | else | |
4382 | Num := New_List (Make_Integer_Literal (Loc, Ind)); | |
4383 | end if; | |
4384 | ||
4385 | Insert_Action (N, | |
4386 | Make_Raise_Constraint_Error (Loc, | |
4387 | Condition => | |
4388 | Make_Not_In (Loc, | |
4389 | Left_Opnd => | |
4390 | Convert_To (Base_Type (Etype (Sub)), | |
4391 | Duplicate_Subexpr_Move_Checks (Sub)), | |
4392 | Right_Opnd => | |
4393 | Make_Attribute_Reference (Loc, | |
cc60bd16 | 4394 | Prefix => |
4395 | Duplicate_Subexpr_Move_Checks (A, Name_Req => True), | |
9dfe12ae | 4396 | Attribute_Name => Name_Range, |
4397 | Expressions => Num)), | |
4398 | Reason => CE_Index_Check_Failed)); | |
4399 | end if; | |
4400 | ||
4401 | Ind := Ind + 1; | |
4402 | Next (Sub); | |
4403 | end loop; | |
4404 | end Generate_Index_Checks; | |
4405 | ||
4406 | -------------------------- | |
4407 | -- Generate_Range_Check -- | |
4408 | -------------------------- | |
4409 | ||
4410 | procedure Generate_Range_Check | |
4411 | (N : Node_Id; | |
4412 | Target_Type : Entity_Id; | |
4413 | Reason : RT_Exception_Code) | |
4414 | is | |
4415 | Loc : constant Source_Ptr := Sloc (N); | |
4416 | Source_Type : constant Entity_Id := Etype (N); | |
4417 | Source_Base_Type : constant Entity_Id := Base_Type (Source_Type); | |
4418 | Target_Base_Type : constant Entity_Id := Base_Type (Target_Type); | |
4419 | ||
4420 | begin | |
feff2f05 | 4421 | -- First special case, if the source type is already within the range |
4422 | -- of the target type, then no check is needed (probably we should have | |
4423 | -- stopped Do_Range_Check from being set in the first place, but better | |
4424 | -- late than later in preventing junk code! | |
9dfe12ae | 4425 | |
feff2f05 | 4426 | -- We do NOT apply this if the source node is a literal, since in this |
4427 | -- case the literal has already been labeled as having the subtype of | |
4428 | -- the target. | |
9dfe12ae | 4429 | |
4430 | if In_Subrange_Of (Source_Type, Target_Type) | |
4431 | and then not | |
4432 | (Nkind (N) = N_Integer_Literal | |
4433 | or else | |
4434 | Nkind (N) = N_Real_Literal | |
4435 | or else | |
4436 | Nkind (N) = N_Character_Literal | |
4437 | or else | |
4438 | (Is_Entity_Name (N) | |
4439 | and then Ekind (Entity (N)) = E_Enumeration_Literal)) | |
4440 | then | |
4441 | return; | |
4442 | end if; | |
4443 | ||
4444 | -- We need a check, so force evaluation of the node, so that it does | |
4445 | -- not get evaluated twice (once for the check, once for the actual | |
4446 | -- reference). Such a double evaluation is always a potential source | |
4447 | -- of inefficiency, and is functionally incorrect in the volatile case. | |
4448 | ||
4449 | if not Is_Entity_Name (N) | |
4450 | or else Treat_As_Volatile (Entity (N)) | |
4451 | then | |
4452 | Force_Evaluation (N); | |
4453 | end if; | |
4454 | ||
feff2f05 | 4455 | -- The easiest case is when Source_Base_Type and Target_Base_Type are |
4456 | -- the same since in this case we can simply do a direct check of the | |
4457 | -- value of N against the bounds of Target_Type. | |
9dfe12ae | 4458 | |
4459 | -- [constraint_error when N not in Target_Type] | |
4460 | ||
4461 | -- Note: this is by far the most common case, for example all cases of | |
4462 | -- checks on the RHS of assignments are in this category, but not all | |
4463 | -- cases are like this. Notably conversions can involve two types. | |
4464 | ||
4465 | if Source_Base_Type = Target_Base_Type then | |
4466 | Insert_Action (N, | |
4467 | Make_Raise_Constraint_Error (Loc, | |
4468 | Condition => | |
4469 | Make_Not_In (Loc, | |
4470 | Left_Opnd => Duplicate_Subexpr (N), | |
4471 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
4472 | Reason => Reason)); | |
4473 | ||
4474 | -- Next test for the case where the target type is within the bounds | |
4475 | -- of the base type of the source type, since in this case we can | |
4476 | -- simply convert these bounds to the base type of T to do the test. | |
4477 | ||
4478 | -- [constraint_error when N not in | |
4479 | -- Source_Base_Type (Target_Type'First) | |
4480 | -- .. | |
4481 | -- Source_Base_Type(Target_Type'Last))] | |
4482 | ||
f2a06be9 | 4483 | -- The conversions will always work and need no check |
9dfe12ae | 4484 | |
4485 | elsif In_Subrange_Of (Target_Type, Source_Base_Type) then | |
4486 | Insert_Action (N, | |
4487 | Make_Raise_Constraint_Error (Loc, | |
4488 | Condition => | |
4489 | Make_Not_In (Loc, | |
4490 | Left_Opnd => Duplicate_Subexpr (N), | |
4491 | ||
4492 | Right_Opnd => | |
4493 | Make_Range (Loc, | |
4494 | Low_Bound => | |
4495 | Convert_To (Source_Base_Type, | |
4496 | Make_Attribute_Reference (Loc, | |
4497 | Prefix => | |
4498 | New_Occurrence_Of (Target_Type, Loc), | |
4499 | Attribute_Name => Name_First)), | |
4500 | ||
4501 | High_Bound => | |
4502 | Convert_To (Source_Base_Type, | |
4503 | Make_Attribute_Reference (Loc, | |
4504 | Prefix => | |
4505 | New_Occurrence_Of (Target_Type, Loc), | |
4506 | Attribute_Name => Name_Last)))), | |
4507 | Reason => Reason)); | |
4508 | ||
feff2f05 | 4509 | -- Note that at this stage we now that the Target_Base_Type is not in |
4510 | -- the range of the Source_Base_Type (since even the Target_Type itself | |
4511 | -- is not in this range). It could still be the case that Source_Type is | |
4512 | -- in range of the target base type since we have not checked that case. | |
9dfe12ae | 4513 | |
feff2f05 | 4514 | -- If that is the case, we can freely convert the source to the target, |
4515 | -- and then test the target result against the bounds. | |
9dfe12ae | 4516 | |
4517 | elsif In_Subrange_Of (Source_Type, Target_Base_Type) then | |
4518 | ||
feff2f05 | 4519 | -- We make a temporary to hold the value of the converted value |
4520 | -- (converted to the base type), and then we will do the test against | |
4521 | -- this temporary. | |
9dfe12ae | 4522 | |
4523 | -- Tnn : constant Target_Base_Type := Target_Base_Type (N); | |
4524 | -- [constraint_error when Tnn not in Target_Type] | |
4525 | ||
4526 | -- Then the conversion itself is replaced by an occurrence of Tnn | |
4527 | ||
4528 | declare | |
4529 | Tnn : constant Entity_Id := | |
4530 | Make_Defining_Identifier (Loc, | |
4531 | Chars => New_Internal_Name ('T')); | |
4532 | ||
4533 | begin | |
4534 | Insert_Actions (N, New_List ( | |
4535 | Make_Object_Declaration (Loc, | |
4536 | Defining_Identifier => Tnn, | |
4537 | Object_Definition => | |
4538 | New_Occurrence_Of (Target_Base_Type, Loc), | |
4539 | Constant_Present => True, | |
4540 | Expression => | |
4541 | Make_Type_Conversion (Loc, | |
4542 | Subtype_Mark => New_Occurrence_Of (Target_Base_Type, Loc), | |
4543 | Expression => Duplicate_Subexpr (N))), | |
4544 | ||
4545 | Make_Raise_Constraint_Error (Loc, | |
4546 | Condition => | |
4547 | Make_Not_In (Loc, | |
4548 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
4549 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
4550 | ||
4551 | Reason => Reason))); | |
4552 | ||
4553 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
2af58f67 | 4554 | |
4555 | -- Set the type of N, because the declaration for Tnn might not | |
4556 | -- be analyzed yet, as is the case if N appears within a record | |
4557 | -- declaration, as a discriminant constraint or expression. | |
4558 | ||
4559 | Set_Etype (N, Target_Base_Type); | |
9dfe12ae | 4560 | end; |
4561 | ||
4562 | -- At this stage, we know that we have two scalar types, which are | |
4563 | -- directly convertible, and where neither scalar type has a base | |
4564 | -- range that is in the range of the other scalar type. | |
4565 | ||
4566 | -- The only way this can happen is with a signed and unsigned type. | |
4567 | -- So test for these two cases: | |
4568 | ||
4569 | else | |
4570 | -- Case of the source is unsigned and the target is signed | |
4571 | ||
4572 | if Is_Unsigned_Type (Source_Base_Type) | |
4573 | and then not Is_Unsigned_Type (Target_Base_Type) | |
4574 | then | |
4575 | -- If the source is unsigned and the target is signed, then we | |
4576 | -- know that the source is not shorter than the target (otherwise | |
4577 | -- the source base type would be in the target base type range). | |
4578 | ||
feff2f05 | 4579 | -- In other words, the unsigned type is either the same size as |
4580 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 4581 | |
4582 | pragma Assert | |
4583 | (Esize (Source_Base_Type) >= Esize (Target_Base_Type)); | |
4584 | ||
4585 | -- We only need to check the low bound if the low bound of the | |
4586 | -- target type is non-negative. If the low bound of the target | |
4587 | -- type is negative, then we know that we will fit fine. | |
4588 | ||
4589 | -- If the high bound of the target type is negative, then we | |
4590 | -- know we have a constraint error, since we can't possibly | |
4591 | -- have a negative source. | |
4592 | ||
4593 | -- With these two checks out of the way, we can do the check | |
4594 | -- using the source type safely | |
4595 | ||
4596 | -- This is definitely the most annoying case! | |
4597 | ||
4598 | -- [constraint_error | |
4599 | -- when (Target_Type'First >= 0 | |
4600 | -- and then | |
4601 | -- N < Source_Base_Type (Target_Type'First)) | |
4602 | -- or else Target_Type'Last < 0 | |
4603 | -- or else N > Source_Base_Type (Target_Type'Last)]; | |
4604 | ||
4605 | -- We turn off all checks since we know that the conversions | |
4606 | -- will work fine, given the guards for negative values. | |
4607 | ||
4608 | Insert_Action (N, | |
4609 | Make_Raise_Constraint_Error (Loc, | |
4610 | Condition => | |
4611 | Make_Or_Else (Loc, | |
4612 | Make_Or_Else (Loc, | |
4613 | Left_Opnd => | |
4614 | Make_And_Then (Loc, | |
4615 | Left_Opnd => Make_Op_Ge (Loc, | |
4616 | Left_Opnd => | |
4617 | Make_Attribute_Reference (Loc, | |
4618 | Prefix => | |
4619 | New_Occurrence_Of (Target_Type, Loc), | |
4620 | Attribute_Name => Name_First), | |
4621 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
4622 | ||
4623 | Right_Opnd => | |
4624 | Make_Op_Lt (Loc, | |
4625 | Left_Opnd => Duplicate_Subexpr (N), | |
4626 | Right_Opnd => | |
4627 | Convert_To (Source_Base_Type, | |
4628 | Make_Attribute_Reference (Loc, | |
4629 | Prefix => | |
4630 | New_Occurrence_Of (Target_Type, Loc), | |
4631 | Attribute_Name => Name_First)))), | |
4632 | ||
4633 | Right_Opnd => | |
4634 | Make_Op_Lt (Loc, | |
4635 | Left_Opnd => | |
4636 | Make_Attribute_Reference (Loc, | |
4637 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
4638 | Attribute_Name => Name_Last), | |
4639 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0))), | |
4640 | ||
4641 | Right_Opnd => | |
4642 | Make_Op_Gt (Loc, | |
4643 | Left_Opnd => Duplicate_Subexpr (N), | |
4644 | Right_Opnd => | |
4645 | Convert_To (Source_Base_Type, | |
4646 | Make_Attribute_Reference (Loc, | |
4647 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
4648 | Attribute_Name => Name_Last)))), | |
4649 | ||
4650 | Reason => Reason), | |
4651 | Suppress => All_Checks); | |
4652 | ||
4653 | -- Only remaining possibility is that the source is signed and | |
4654 | -- the target is unsigned | |
4655 | ||
4656 | else | |
4657 | pragma Assert (not Is_Unsigned_Type (Source_Base_Type) | |
4658 | and then Is_Unsigned_Type (Target_Base_Type)); | |
4659 | ||
feff2f05 | 4660 | -- If the source is signed and the target is unsigned, then we |
4661 | -- know that the target is not shorter than the source (otherwise | |
4662 | -- the target base type would be in the source base type range). | |
9dfe12ae | 4663 | |
feff2f05 | 4664 | -- In other words, the unsigned type is either the same size as |
4665 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 4666 | |
feff2f05 | 4667 | -- Clearly we have an error if the source value is negative since |
4668 | -- no unsigned type can have negative values. If the source type | |
4669 | -- is non-negative, then the check can be done using the target | |
4670 | -- type. | |
9dfe12ae | 4671 | |
4672 | -- Tnn : constant Target_Base_Type (N) := Target_Type; | |
4673 | ||
4674 | -- [constraint_error | |
4675 | -- when N < 0 or else Tnn not in Target_Type]; | |
4676 | ||
feff2f05 | 4677 | -- We turn off all checks for the conversion of N to the target |
4678 | -- base type, since we generate the explicit check to ensure that | |
4679 | -- the value is non-negative | |
9dfe12ae | 4680 | |
4681 | declare | |
4682 | Tnn : constant Entity_Id := | |
4683 | Make_Defining_Identifier (Loc, | |
4684 | Chars => New_Internal_Name ('T')); | |
4685 | ||
4686 | begin | |
4687 | Insert_Actions (N, New_List ( | |
4688 | Make_Object_Declaration (Loc, | |
4689 | Defining_Identifier => Tnn, | |
4690 | Object_Definition => | |
4691 | New_Occurrence_Of (Target_Base_Type, Loc), | |
4692 | Constant_Present => True, | |
4693 | Expression => | |
4694 | Make_Type_Conversion (Loc, | |
4695 | Subtype_Mark => | |
4696 | New_Occurrence_Of (Target_Base_Type, Loc), | |
4697 | Expression => Duplicate_Subexpr (N))), | |
4698 | ||
4699 | Make_Raise_Constraint_Error (Loc, | |
4700 | Condition => | |
4701 | Make_Or_Else (Loc, | |
4702 | Left_Opnd => | |
4703 | Make_Op_Lt (Loc, | |
4704 | Left_Opnd => Duplicate_Subexpr (N), | |
4705 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
4706 | ||
4707 | Right_Opnd => | |
4708 | Make_Not_In (Loc, | |
4709 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
4710 | Right_Opnd => | |
4711 | New_Occurrence_Of (Target_Type, Loc))), | |
4712 | ||
4713 | Reason => Reason)), | |
4714 | Suppress => All_Checks); | |
4715 | ||
feff2f05 | 4716 | -- Set the Etype explicitly, because Insert_Actions may have |
4717 | -- placed the declaration in the freeze list for an enclosing | |
4718 | -- construct, and thus it is not analyzed yet. | |
9dfe12ae | 4719 | |
4720 | Set_Etype (Tnn, Target_Base_Type); | |
4721 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
4722 | end; | |
4723 | end if; | |
4724 | end if; | |
4725 | end Generate_Range_Check; | |
4726 | ||
2af58f67 | 4727 | ------------------ |
4728 | -- Get_Check_Id -- | |
4729 | ------------------ | |
4730 | ||
4731 | function Get_Check_Id (N : Name_Id) return Check_Id is | |
4732 | begin | |
4733 | -- For standard check name, we can do a direct computation | |
4734 | ||
4735 | if N in First_Check_Name .. Last_Check_Name then | |
4736 | return Check_Id (N - (First_Check_Name - 1)); | |
4737 | ||
4738 | -- For non-standard names added by pragma Check_Name, search table | |
4739 | ||
4740 | else | |
4741 | for J in All_Checks + 1 .. Check_Names.Last loop | |
4742 | if Check_Names.Table (J) = N then | |
4743 | return J; | |
4744 | end if; | |
4745 | end loop; | |
4746 | end if; | |
4747 | ||
4748 | -- No matching name found | |
4749 | ||
4750 | return No_Check_Id; | |
4751 | end Get_Check_Id; | |
4752 | ||
ee6ba406 | 4753 | --------------------- |
4754 | -- Get_Discriminal -- | |
4755 | --------------------- | |
4756 | ||
4757 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is | |
4758 | Loc : constant Source_Ptr := Sloc (E); | |
4759 | D : Entity_Id; | |
4760 | Sc : Entity_Id; | |
4761 | ||
4762 | begin | |
0577b0b1 | 4763 | -- The bound can be a bona fide parameter of a protected operation, |
4764 | -- rather than a prival encoded as an in-parameter. | |
4765 | ||
4766 | if No (Discriminal_Link (Entity (Bound))) then | |
4767 | return Bound; | |
4768 | end if; | |
4769 | ||
2af58f67 | 4770 | -- Climb the scope stack looking for an enclosing protected type. If |
4771 | -- we run out of scopes, return the bound itself. | |
4772 | ||
4773 | Sc := Scope (E); | |
4774 | while Present (Sc) loop | |
4775 | if Sc = Standard_Standard then | |
4776 | return Bound; | |
4777 | ||
4778 | elsif Ekind (Sc) = E_Protected_Type then | |
4779 | exit; | |
4780 | end if; | |
4781 | ||
4782 | Sc := Scope (Sc); | |
4783 | end loop; | |
4784 | ||
ee6ba406 | 4785 | D := First_Discriminant (Sc); |
2af58f67 | 4786 | while Present (D) loop |
4787 | if Chars (D) = Chars (Bound) then | |
4788 | return New_Occurrence_Of (Discriminal (D), Loc); | |
4789 | end if; | |
ee6ba406 | 4790 | |
ee6ba406 | 4791 | Next_Discriminant (D); |
4792 | end loop; | |
4793 | ||
2af58f67 | 4794 | return Bound; |
ee6ba406 | 4795 | end Get_Discriminal; |
4796 | ||
2af58f67 | 4797 | ---------------------- |
4798 | -- Get_Range_Checks -- | |
4799 | ---------------------- | |
4800 | ||
4801 | function Get_Range_Checks | |
4802 | (Ck_Node : Node_Id; | |
4803 | Target_Typ : Entity_Id; | |
4804 | Source_Typ : Entity_Id := Empty; | |
4805 | Warn_Node : Node_Id := Empty) return Check_Result | |
4806 | is | |
4807 | begin | |
4808 | return Selected_Range_Checks | |
4809 | (Ck_Node, Target_Typ, Source_Typ, Warn_Node); | |
4810 | end Get_Range_Checks; | |
4811 | ||
ee6ba406 | 4812 | ------------------ |
4813 | -- Guard_Access -- | |
4814 | ------------------ | |
4815 | ||
4816 | function Guard_Access | |
4817 | (Cond : Node_Id; | |
4818 | Loc : Source_Ptr; | |
314a23b6 | 4819 | Ck_Node : Node_Id) return Node_Id |
ee6ba406 | 4820 | is |
4821 | begin | |
4822 | if Nkind (Cond) = N_Or_Else then | |
4823 | Set_Paren_Count (Cond, 1); | |
4824 | end if; | |
4825 | ||
4826 | if Nkind (Ck_Node) = N_Allocator then | |
4827 | return Cond; | |
4828 | else | |
4829 | return | |
4830 | Make_And_Then (Loc, | |
4831 | Left_Opnd => | |
4832 | Make_Op_Ne (Loc, | |
9dfe12ae | 4833 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), |
ee6ba406 | 4834 | Right_Opnd => Make_Null (Loc)), |
4835 | Right_Opnd => Cond); | |
4836 | end if; | |
4837 | end Guard_Access; | |
4838 | ||
4839 | ----------------------------- | |
4840 | -- Index_Checks_Suppressed -- | |
4841 | ----------------------------- | |
4842 | ||
4843 | function Index_Checks_Suppressed (E : Entity_Id) return Boolean is | |
4844 | begin | |
9dfe12ae | 4845 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
4846 | return Is_Check_Suppressed (E, Index_Check); | |
4847 | else | |
4848 | return Scope_Suppress (Index_Check); | |
4849 | end if; | |
ee6ba406 | 4850 | end Index_Checks_Suppressed; |
4851 | ||
4852 | ---------------- | |
4853 | -- Initialize -- | |
4854 | ---------------- | |
4855 | ||
4856 | procedure Initialize is | |
4857 | begin | |
4858 | for J in Determine_Range_Cache_N'Range loop | |
4859 | Determine_Range_Cache_N (J) := Empty; | |
4860 | end loop; | |
2af58f67 | 4861 | |
4862 | Check_Names.Init; | |
4863 | ||
4864 | for J in Int range 1 .. All_Checks loop | |
4865 | Check_Names.Append (Name_Id (Int (First_Check_Name) + J - 1)); | |
4866 | end loop; | |
ee6ba406 | 4867 | end Initialize; |
4868 | ||
4869 | ------------------------- | |
4870 | -- Insert_Range_Checks -- | |
4871 | ------------------------- | |
4872 | ||
4873 | procedure Insert_Range_Checks | |
4874 | (Checks : Check_Result; | |
4875 | Node : Node_Id; | |
4876 | Suppress_Typ : Entity_Id; | |
4877 | Static_Sloc : Source_Ptr := No_Location; | |
4878 | Flag_Node : Node_Id := Empty; | |
4879 | Do_Before : Boolean := False) | |
4880 | is | |
4881 | Internal_Flag_Node : Node_Id := Flag_Node; | |
4882 | Internal_Static_Sloc : Source_Ptr := Static_Sloc; | |
4883 | ||
4884 | Check_Node : Node_Id; | |
4885 | Checks_On : constant Boolean := | |
4886 | (not Index_Checks_Suppressed (Suppress_Typ)) | |
4887 | or else | |
4888 | (not Range_Checks_Suppressed (Suppress_Typ)); | |
4889 | ||
4890 | begin | |
feff2f05 | 4891 | -- For now we just return if Checks_On is false, however this should be |
4892 | -- enhanced to check for an always True value in the condition and to | |
4893 | -- generate a compilation warning??? | |
ee6ba406 | 4894 | |
4895 | if not Expander_Active or else not Checks_On then | |
4896 | return; | |
4897 | end if; | |
4898 | ||
4899 | if Static_Sloc = No_Location then | |
4900 | Internal_Static_Sloc := Sloc (Node); | |
4901 | end if; | |
4902 | ||
4903 | if No (Flag_Node) then | |
4904 | Internal_Flag_Node := Node; | |
4905 | end if; | |
4906 | ||
4907 | for J in 1 .. 2 loop | |
4908 | exit when No (Checks (J)); | |
4909 | ||
4910 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
4911 | and then Present (Condition (Checks (J))) | |
4912 | then | |
4913 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
4914 | Check_Node := Checks (J); | |
4915 | Mark_Rewrite_Insertion (Check_Node); | |
4916 | ||
4917 | if Do_Before then | |
4918 | Insert_Before_And_Analyze (Node, Check_Node); | |
4919 | else | |
4920 | Insert_After_And_Analyze (Node, Check_Node); | |
4921 | end if; | |
4922 | ||
4923 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
4924 | end if; | |
4925 | ||
4926 | else | |
4927 | Check_Node := | |
f15731c4 | 4928 | Make_Raise_Constraint_Error (Internal_Static_Sloc, |
4929 | Reason => CE_Range_Check_Failed); | |
ee6ba406 | 4930 | Mark_Rewrite_Insertion (Check_Node); |
4931 | ||
4932 | if Do_Before then | |
4933 | Insert_Before_And_Analyze (Node, Check_Node); | |
4934 | else | |
4935 | Insert_After_And_Analyze (Node, Check_Node); | |
4936 | end if; | |
4937 | end if; | |
4938 | end loop; | |
4939 | end Insert_Range_Checks; | |
4940 | ||
4941 | ------------------------ | |
4942 | -- Insert_Valid_Check -- | |
4943 | ------------------------ | |
4944 | ||
4945 | procedure Insert_Valid_Check (Expr : Node_Id) is | |
4946 | Loc : constant Source_Ptr := Sloc (Expr); | |
8b718dab | 4947 | Exp : Node_Id; |
ee6ba406 | 4948 | |
4949 | begin | |
4950 | -- Do not insert if checks off, or if not checking validity | |
4951 | ||
0577b0b1 | 4952 | if not Validity_Checks_On |
4953 | or else Range_Or_Validity_Checks_Suppressed (Expr) | |
ee6ba406 | 4954 | then |
8b718dab | 4955 | return; |
4956 | end if; | |
ee6ba406 | 4957 | |
8b718dab | 4958 | -- If we have a checked conversion, then validity check applies to |
4959 | -- the expression inside the conversion, not the result, since if | |
4960 | -- the expression inside is valid, then so is the conversion result. | |
ee6ba406 | 4961 | |
8b718dab | 4962 | Exp := Expr; |
4963 | while Nkind (Exp) = N_Type_Conversion loop | |
4964 | Exp := Expression (Exp); | |
4965 | end loop; | |
4966 | ||
0577b0b1 | 4967 | -- We are about to insert the validity check for Exp. We save and |
4968 | -- reset the Do_Range_Check flag over this validity check, and then | |
4969 | -- put it back for the final original reference (Exp may be rewritten). | |
4970 | ||
4971 | declare | |
4972 | DRC : constant Boolean := Do_Range_Check (Exp); | |
05fcfafb | 4973 | |
0577b0b1 | 4974 | begin |
4975 | Set_Do_Range_Check (Exp, False); | |
4976 | ||
4977 | -- Insert the validity check. Note that we do this with validity | |
4978 | -- checks turned off, to avoid recursion, we do not want validity | |
4979 | -- checks on the validity checking code itself! | |
4980 | ||
4981 | Insert_Action | |
4982 | (Expr, | |
4983 | Make_Raise_Constraint_Error (Loc, | |
4984 | Condition => | |
4985 | Make_Op_Not (Loc, | |
4986 | Right_Opnd => | |
4987 | Make_Attribute_Reference (Loc, | |
4988 | Prefix => | |
4989 | Duplicate_Subexpr_No_Checks (Exp, Name_Req => True), | |
4990 | Attribute_Name => Name_Valid)), | |
4991 | Reason => CE_Invalid_Data), | |
4992 | Suppress => Validity_Check); | |
4993 | ||
4994 | -- If the expression is a a reference to an element of a bit-packed | |
4995 | -- array, then it is rewritten as a renaming declaration. If the | |
4996 | -- expression is an actual in a call, it has not been expanded, | |
4997 | -- waiting for the proper point at which to do it. The same happens | |
4998 | -- with renamings, so that we have to force the expansion now. This | |
4999 | -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb | |
5000 | -- and exp_ch6.adb. | |
5001 | ||
5002 | if Is_Entity_Name (Exp) | |
5003 | and then Nkind (Parent (Entity (Exp))) = | |
5004 | N_Object_Renaming_Declaration | |
5005 | then | |
5006 | declare | |
5007 | Old_Exp : constant Node_Id := Name (Parent (Entity (Exp))); | |
5008 | begin | |
5009 | if Nkind (Old_Exp) = N_Indexed_Component | |
5010 | and then Is_Bit_Packed_Array (Etype (Prefix (Old_Exp))) | |
5011 | then | |
5012 | Expand_Packed_Element_Reference (Old_Exp); | |
5013 | end if; | |
5014 | end; | |
5015 | end if; | |
5016 | ||
5017 | -- Put back the Do_Range_Check flag on the resulting (possibly | |
5018 | -- rewritten) expression. | |
5019 | ||
5020 | -- Note: it might be thought that a validity check is not required | |
5021 | -- when a range check is present, but that's not the case, because | |
5022 | -- the back end is allowed to assume for the range check that the | |
5023 | -- operand is within its declared range (an assumption that validity | |
5024 | -- checking is all about NOT assuming!) | |
5025 | ||
00c403ee | 5026 | -- Note: no need to worry about Possible_Local_Raise here, it will |
5027 | -- already have been called if original node has Do_Range_Check set. | |
5028 | ||
0577b0b1 | 5029 | Set_Do_Range_Check (Exp, DRC); |
5030 | end; | |
ee6ba406 | 5031 | end Insert_Valid_Check; |
5032 | ||
fa7497e8 | 5033 | ---------------------------------- |
5034 | -- Install_Null_Excluding_Check -- | |
5035 | ---------------------------------- | |
5036 | ||
5037 | procedure Install_Null_Excluding_Check (N : Node_Id) is | |
84d0d4a5 | 5038 | Loc : constant Source_Ptr := Sloc (N); |
5039 | Typ : constant Entity_Id := Etype (N); | |
5040 | ||
7870823d | 5041 | function In_Declarative_Region_Of_Subprogram_Body return Boolean; |
5042 | -- Determine whether node N, a reference to an *in* parameter, is | |
5043 | -- inside the declarative region of the current subprogram body. | |
5044 | ||
84d0d4a5 | 5045 | procedure Mark_Non_Null; |
7870823d | 5046 | -- After installation of check, if the node in question is an entity |
5047 | -- name, then mark this entity as non-null if possible. | |
5048 | ||
5049 | ---------------------------------------------- | |
5050 | -- In_Declarative_Region_Of_Subprogram_Body -- | |
5051 | ---------------------------------------------- | |
5052 | ||
5053 | function In_Declarative_Region_Of_Subprogram_Body return Boolean is | |
5054 | E : constant Entity_Id := Entity (N); | |
5055 | S : constant Entity_Id := Current_Scope; | |
5056 | S_Par : Node_Id; | |
5057 | ||
5058 | begin | |
5059 | pragma Assert (Ekind (E) = E_In_Parameter); | |
5060 | ||
5061 | -- Two initial context checks. We must be inside a subprogram body | |
5062 | -- with declarations and reference must not appear in nested scopes. | |
5063 | ||
5064 | if (Ekind (S) /= E_Function | |
5065 | and then Ekind (S) /= E_Procedure) | |
5066 | or else Scope (E) /= S | |
5067 | then | |
5068 | return False; | |
5069 | end if; | |
5070 | ||
5071 | S_Par := Parent (Parent (S)); | |
5072 | ||
5073 | if Nkind (S_Par) /= N_Subprogram_Body | |
5074 | or else No (Declarations (S_Par)) | |
5075 | then | |
5076 | return False; | |
5077 | end if; | |
5078 | ||
5079 | declare | |
5080 | N_Decl : Node_Id; | |
5081 | P : Node_Id; | |
5082 | ||
5083 | begin | |
5084 | -- Retrieve the declaration node of N (if any). Note that N | |
5085 | -- may be a part of a complex initialization expression. | |
5086 | ||
5087 | P := Parent (N); | |
5088 | N_Decl := Empty; | |
5089 | while Present (P) loop | |
5090 | ||
5091 | -- While traversing the parent chain, we find that N | |
5092 | -- belongs to a statement, thus it may never appear in | |
5093 | -- a declarative region. | |
5094 | ||
5095 | if Nkind (P) in N_Statement_Other_Than_Procedure_Call | |
5096 | or else Nkind (P) = N_Procedure_Call_Statement | |
5097 | then | |
5098 | return False; | |
5099 | end if; | |
5100 | ||
5101 | if Nkind (P) in N_Declaration | |
5102 | and then Nkind (P) not in N_Subprogram_Specification | |
5103 | then | |
5104 | N_Decl := P; | |
5105 | exit; | |
5106 | end if; | |
5107 | ||
5108 | P := Parent (P); | |
5109 | end loop; | |
5110 | ||
5111 | if No (N_Decl) then | |
5112 | return False; | |
5113 | end if; | |
5114 | ||
5115 | return List_Containing (N_Decl) = Declarations (S_Par); | |
5116 | end; | |
5117 | end In_Declarative_Region_Of_Subprogram_Body; | |
84d0d4a5 | 5118 | |
5119 | ------------------- | |
5120 | -- Mark_Non_Null -- | |
5121 | ------------------- | |
5122 | ||
5123 | procedure Mark_Non_Null is | |
5124 | begin | |
7870823d | 5125 | -- Only case of interest is if node N is an entity name |
5126 | ||
84d0d4a5 | 5127 | if Is_Entity_Name (N) then |
7870823d | 5128 | |
5129 | -- For sure, we want to clear an indication that this is known to | |
5130 | -- be null, since if we get past this check, it definitely is not! | |
5131 | ||
84d0d4a5 | 5132 | Set_Is_Known_Null (Entity (N), False); |
5133 | ||
7870823d | 5134 | -- We can mark the entity as known to be non-null if either it is |
5135 | -- safe to capture the value, or in the case of an IN parameter, | |
5136 | -- which is a constant, if the check we just installed is in the | |
5137 | -- declarative region of the subprogram body. In this latter case, | |
5138 | -- a check is decisive for the rest of the body, since we know we | |
5139 | -- must complete all declarations before executing the body. | |
5140 | ||
5141 | if Safe_To_Capture_Value (N, Entity (N)) | |
5142 | or else | |
5143 | (Ekind (Entity (N)) = E_In_Parameter | |
5144 | and then In_Declarative_Region_Of_Subprogram_Body) | |
5145 | then | |
5146 | Set_Is_Known_Non_Null (Entity (N)); | |
84d0d4a5 | 5147 | end if; |
5148 | end if; | |
5149 | end Mark_Non_Null; | |
5150 | ||
5151 | -- Start of processing for Install_Null_Excluding_Check | |
fa7497e8 | 5152 | |
5153 | begin | |
84d0d4a5 | 5154 | pragma Assert (Is_Access_Type (Typ)); |
fa7497e8 | 5155 | |
84d0d4a5 | 5156 | -- No check inside a generic (why not???) |
fa7497e8 | 5157 | |
84d0d4a5 | 5158 | if Inside_A_Generic then |
fa7497e8 | 5159 | return; |
84d0d4a5 | 5160 | end if; |
5161 | ||
5162 | -- No check needed if known to be non-null | |
5163 | ||
5164 | if Known_Non_Null (N) then | |
05fcfafb | 5165 | return; |
84d0d4a5 | 5166 | end if; |
fa7497e8 | 5167 | |
84d0d4a5 | 5168 | -- If known to be null, here is where we generate a compile time check |
5169 | ||
5170 | if Known_Null (N) then | |
5171 | Apply_Compile_Time_Constraint_Error | |
5172 | (N, | |
5173 | "null value not allowed here?", | |
5174 | CE_Access_Check_Failed); | |
5175 | Mark_Non_Null; | |
5176 | return; | |
5177 | end if; | |
5178 | ||
5179 | -- If entity is never assigned, for sure a warning is appropriate | |
5180 | ||
5181 | if Is_Entity_Name (N) then | |
5182 | Check_Unset_Reference (N); | |
fa7497e8 | 5183 | end if; |
84d0d4a5 | 5184 | |
5185 | -- No check needed if checks are suppressed on the range. Note that we | |
5186 | -- don't set Is_Known_Non_Null in this case (we could legitimately do | |
5187 | -- so, since the program is erroneous, but we don't like to casually | |
5188 | -- propagate such conclusions from erroneosity). | |
5189 | ||
5190 | if Access_Checks_Suppressed (Typ) then | |
5191 | return; | |
5192 | end if; | |
5193 | ||
2af58f67 | 5194 | -- No check needed for access to concurrent record types generated by |
5195 | -- the expander. This is not just an optimization (though it does indeed | |
5196 | -- remove junk checks). It also avoids generation of junk warnings. | |
5197 | ||
5198 | if Nkind (N) in N_Has_Chars | |
5199 | and then Chars (N) = Name_uObject | |
5200 | and then Is_Concurrent_Record_Type | |
5201 | (Directly_Designated_Type (Etype (N))) | |
5202 | then | |
5203 | return; | |
5204 | end if; | |
5205 | ||
84d0d4a5 | 5206 | -- Otherwise install access check |
5207 | ||
5208 | Insert_Action (N, | |
5209 | Make_Raise_Constraint_Error (Loc, | |
5210 | Condition => | |
5211 | Make_Op_Eq (Loc, | |
5212 | Left_Opnd => Duplicate_Subexpr_Move_Checks (N), | |
5213 | Right_Opnd => Make_Null (Loc)), | |
5214 | Reason => CE_Access_Check_Failed)); | |
5215 | ||
5216 | Mark_Non_Null; | |
fa7497e8 | 5217 | end Install_Null_Excluding_Check; |
5218 | ||
ee6ba406 | 5219 | -------------------------- |
5220 | -- Install_Static_Check -- | |
5221 | -------------------------- | |
5222 | ||
5223 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is | |
5224 | Stat : constant Boolean := Is_Static_Expression (R_Cno); | |
5225 | Typ : constant Entity_Id := Etype (R_Cno); | |
5226 | ||
5227 | begin | |
f15731c4 | 5228 | Rewrite (R_Cno, |
5229 | Make_Raise_Constraint_Error (Loc, | |
5230 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 5231 | Set_Analyzed (R_Cno); |
5232 | Set_Etype (R_Cno, Typ); | |
5233 | Set_Raises_Constraint_Error (R_Cno); | |
5234 | Set_Is_Static_Expression (R_Cno, Stat); | |
5235 | end Install_Static_Check; | |
5236 | ||
9dfe12ae | 5237 | --------------------- |
5238 | -- Kill_All_Checks -- | |
5239 | --------------------- | |
5240 | ||
5241 | procedure Kill_All_Checks is | |
5242 | begin | |
5243 | if Debug_Flag_CC then | |
5244 | w ("Kill_All_Checks"); | |
5245 | end if; | |
5246 | ||
feff2f05 | 5247 | -- We reset the number of saved checks to zero, and also modify all |
5248 | -- stack entries for statement ranges to indicate that the number of | |
5249 | -- checks at each level is now zero. | |
9dfe12ae | 5250 | |
5251 | Num_Saved_Checks := 0; | |
5252 | ||
96da3284 | 5253 | -- Note: the Int'Min here avoids any possibility of J being out of |
5254 | -- range when called from e.g. Conditional_Statements_Begin. | |
5255 | ||
5256 | for J in 1 .. Int'Min (Saved_Checks_TOS, Saved_Checks_Stack'Last) loop | |
9dfe12ae | 5257 | Saved_Checks_Stack (J) := 0; |
5258 | end loop; | |
5259 | end Kill_All_Checks; | |
5260 | ||
5261 | ----------------- | |
5262 | -- Kill_Checks -- | |
5263 | ----------------- | |
5264 | ||
5265 | procedure Kill_Checks (V : Entity_Id) is | |
5266 | begin | |
5267 | if Debug_Flag_CC then | |
5268 | w ("Kill_Checks for entity", Int (V)); | |
5269 | end if; | |
5270 | ||
5271 | for J in 1 .. Num_Saved_Checks loop | |
5272 | if Saved_Checks (J).Entity = V then | |
5273 | if Debug_Flag_CC then | |
5274 | w (" Checks killed for saved check ", J); | |
5275 | end if; | |
5276 | ||
5277 | Saved_Checks (J).Killed := True; | |
5278 | end if; | |
5279 | end loop; | |
5280 | end Kill_Checks; | |
5281 | ||
ee6ba406 | 5282 | ------------------------------ |
5283 | -- Length_Checks_Suppressed -- | |
5284 | ------------------------------ | |
5285 | ||
5286 | function Length_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5287 | begin | |
9dfe12ae | 5288 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
5289 | return Is_Check_Suppressed (E, Length_Check); | |
5290 | else | |
5291 | return Scope_Suppress (Length_Check); | |
5292 | end if; | |
ee6ba406 | 5293 | end Length_Checks_Suppressed; |
5294 | ||
5295 | -------------------------------- | |
5296 | -- Overflow_Checks_Suppressed -- | |
5297 | -------------------------------- | |
5298 | ||
5299 | function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5300 | begin | |
9dfe12ae | 5301 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
5302 | return Is_Check_Suppressed (E, Overflow_Check); | |
5303 | else | |
5304 | return Scope_Suppress (Overflow_Check); | |
5305 | end if; | |
ee6ba406 | 5306 | end Overflow_Checks_Suppressed; |
ee6ba406 | 5307 | ----------------------------- |
5308 | -- Range_Checks_Suppressed -- | |
5309 | ----------------------------- | |
5310 | ||
5311 | function Range_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5312 | begin | |
9dfe12ae | 5313 | if Present (E) then |
5314 | ||
5315 | -- Note: for now we always suppress range checks on Vax float types, | |
5316 | -- since Gigi does not know how to generate these checks. | |
5317 | ||
5318 | if Vax_Float (E) then | |
5319 | return True; | |
5320 | elsif Kill_Range_Checks (E) then | |
5321 | return True; | |
5322 | elsif Checks_May_Be_Suppressed (E) then | |
5323 | return Is_Check_Suppressed (E, Range_Check); | |
5324 | end if; | |
5325 | end if; | |
ee6ba406 | 5326 | |
9dfe12ae | 5327 | return Scope_Suppress (Range_Check); |
ee6ba406 | 5328 | end Range_Checks_Suppressed; |
5329 | ||
0577b0b1 | 5330 | ----------------------------------------- |
5331 | -- Range_Or_Validity_Checks_Suppressed -- | |
5332 | ----------------------------------------- | |
5333 | ||
5334 | -- Note: the coding would be simpler here if we simply made appropriate | |
5335 | -- calls to Range/Validity_Checks_Suppressed, but that would result in | |
5336 | -- duplicated checks which we prefer to avoid. | |
5337 | ||
5338 | function Range_Or_Validity_Checks_Suppressed | |
5339 | (Expr : Node_Id) return Boolean | |
5340 | is | |
5341 | begin | |
5342 | -- Immediate return if scope checks suppressed for either check | |
5343 | ||
5344 | if Scope_Suppress (Range_Check) or Scope_Suppress (Validity_Check) then | |
5345 | return True; | |
5346 | end if; | |
5347 | ||
5348 | -- If no expression, that's odd, decide that checks are suppressed, | |
5349 | -- since we don't want anyone trying to do checks in this case, which | |
5350 | -- is most likely the result of some other error. | |
5351 | ||
5352 | if No (Expr) then | |
5353 | return True; | |
5354 | end if; | |
5355 | ||
5356 | -- Expression is present, so perform suppress checks on type | |
5357 | ||
5358 | declare | |
5359 | Typ : constant Entity_Id := Etype (Expr); | |
5360 | begin | |
5361 | if Vax_Float (Typ) then | |
5362 | return True; | |
5363 | elsif Checks_May_Be_Suppressed (Typ) | |
5364 | and then (Is_Check_Suppressed (Typ, Range_Check) | |
5365 | or else | |
5366 | Is_Check_Suppressed (Typ, Validity_Check)) | |
5367 | then | |
5368 | return True; | |
5369 | end if; | |
5370 | end; | |
5371 | ||
5372 | -- If expression is an entity name, perform checks on this entity | |
5373 | ||
5374 | if Is_Entity_Name (Expr) then | |
5375 | declare | |
5376 | Ent : constant Entity_Id := Entity (Expr); | |
5377 | begin | |
5378 | if Checks_May_Be_Suppressed (Ent) then | |
5379 | return Is_Check_Suppressed (Ent, Range_Check) | |
5380 | or else Is_Check_Suppressed (Ent, Validity_Check); | |
5381 | end if; | |
5382 | end; | |
5383 | end if; | |
5384 | ||
5385 | -- If we fall through, no checks suppressed | |
5386 | ||
5387 | return False; | |
5388 | end Range_Or_Validity_Checks_Suppressed; | |
5389 | ||
226494a3 | 5390 | ------------------- |
5391 | -- Remove_Checks -- | |
5392 | ------------------- | |
5393 | ||
5394 | procedure Remove_Checks (Expr : Node_Id) is | |
226494a3 | 5395 | function Process (N : Node_Id) return Traverse_Result; |
5396 | -- Process a single node during the traversal | |
5397 | ||
8f6e4fd5 | 5398 | procedure Traverse is new Traverse_Proc (Process); |
5399 | -- The traversal procedure itself | |
226494a3 | 5400 | |
5401 | ------------- | |
5402 | -- Process -- | |
5403 | ------------- | |
5404 | ||
5405 | function Process (N : Node_Id) return Traverse_Result is | |
5406 | begin | |
5407 | if Nkind (N) not in N_Subexpr then | |
5408 | return Skip; | |
5409 | end if; | |
5410 | ||
5411 | Set_Do_Range_Check (N, False); | |
5412 | ||
5413 | case Nkind (N) is | |
5414 | when N_And_Then => | |
8f6e4fd5 | 5415 | Traverse (Left_Opnd (N)); |
226494a3 | 5416 | return Skip; |
5417 | ||
5418 | when N_Attribute_Reference => | |
226494a3 | 5419 | Set_Do_Overflow_Check (N, False); |
5420 | ||
226494a3 | 5421 | when N_Function_Call => |
5422 | Set_Do_Tag_Check (N, False); | |
5423 | ||
226494a3 | 5424 | when N_Op => |
5425 | Set_Do_Overflow_Check (N, False); | |
5426 | ||
5427 | case Nkind (N) is | |
5428 | when N_Op_Divide => | |
5429 | Set_Do_Division_Check (N, False); | |
5430 | ||
5431 | when N_Op_And => | |
5432 | Set_Do_Length_Check (N, False); | |
5433 | ||
5434 | when N_Op_Mod => | |
5435 | Set_Do_Division_Check (N, False); | |
5436 | ||
5437 | when N_Op_Or => | |
5438 | Set_Do_Length_Check (N, False); | |
5439 | ||
5440 | when N_Op_Rem => | |
5441 | Set_Do_Division_Check (N, False); | |
5442 | ||
5443 | when N_Op_Xor => | |
5444 | Set_Do_Length_Check (N, False); | |
5445 | ||
5446 | when others => | |
5447 | null; | |
5448 | end case; | |
5449 | ||
5450 | when N_Or_Else => | |
8f6e4fd5 | 5451 | Traverse (Left_Opnd (N)); |
226494a3 | 5452 | return Skip; |
5453 | ||
5454 | when N_Selected_Component => | |
226494a3 | 5455 | Set_Do_Discriminant_Check (N, False); |
5456 | ||
226494a3 | 5457 | when N_Type_Conversion => |
9dfe12ae | 5458 | Set_Do_Length_Check (N, False); |
5459 | Set_Do_Tag_Check (N, False); | |
226494a3 | 5460 | Set_Do_Overflow_Check (N, False); |
226494a3 | 5461 | |
5462 | when others => | |
5463 | null; | |
5464 | end case; | |
5465 | ||
5466 | return OK; | |
5467 | end Process; | |
5468 | ||
5469 | -- Start of processing for Remove_Checks | |
5470 | ||
5471 | begin | |
8f6e4fd5 | 5472 | Traverse (Expr); |
226494a3 | 5473 | end Remove_Checks; |
5474 | ||
ee6ba406 | 5475 | ---------------------------- |
5476 | -- Selected_Length_Checks -- | |
5477 | ---------------------------- | |
5478 | ||
5479 | function Selected_Length_Checks | |
5480 | (Ck_Node : Node_Id; | |
5481 | Target_Typ : Entity_Id; | |
5482 | Source_Typ : Entity_Id; | |
314a23b6 | 5483 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 5484 | is |
5485 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
5486 | S_Typ : Entity_Id; | |
5487 | T_Typ : Entity_Id; | |
5488 | Expr_Actual : Node_Id; | |
5489 | Exptyp : Entity_Id; | |
5490 | Cond : Node_Id := Empty; | |
5491 | Do_Access : Boolean := False; | |
5492 | Wnode : Node_Id := Warn_Node; | |
5493 | Ret_Result : Check_Result := (Empty, Empty); | |
5494 | Num_Checks : Natural := 0; | |
5495 | ||
5496 | procedure Add_Check (N : Node_Id); | |
5497 | -- Adds the action given to Ret_Result if N is non-Empty | |
5498 | ||
5499 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id; | |
5500 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id; | |
314a23b6 | 5501 | -- Comments required ??? |
ee6ba406 | 5502 | |
5503 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean; | |
5504 | -- True for equal literals and for nodes that denote the same constant | |
5f260d20 | 5505 | -- entity, even if its value is not a static constant. This includes the |
9dfe12ae | 5506 | -- case of a discriminal reference within an init proc. Removes some |
5f260d20 | 5507 | -- obviously superfluous checks. |
ee6ba406 | 5508 | |
5509 | function Length_E_Cond | |
5510 | (Exptyp : Entity_Id; | |
5511 | Typ : Entity_Id; | |
314a23b6 | 5512 | Indx : Nat) return Node_Id; |
ee6ba406 | 5513 | -- Returns expression to compute: |
5514 | -- Typ'Length /= Exptyp'Length | |
5515 | ||
5516 | function Length_N_Cond | |
5517 | (Expr : Node_Id; | |
5518 | Typ : Entity_Id; | |
314a23b6 | 5519 | Indx : Nat) return Node_Id; |
ee6ba406 | 5520 | -- Returns expression to compute: |
5521 | -- Typ'Length /= Expr'Length | |
5522 | ||
5523 | --------------- | |
5524 | -- Add_Check -- | |
5525 | --------------- | |
5526 | ||
5527 | procedure Add_Check (N : Node_Id) is | |
5528 | begin | |
5529 | if Present (N) then | |
5530 | ||
5531 | -- For now, ignore attempt to place more than 2 checks ??? | |
5532 | ||
5533 | if Num_Checks = 2 then | |
5534 | return; | |
5535 | end if; | |
5536 | ||
5537 | pragma Assert (Num_Checks <= 1); | |
5538 | Num_Checks := Num_Checks + 1; | |
5539 | Ret_Result (Num_Checks) := N; | |
5540 | end if; | |
5541 | end Add_Check; | |
5542 | ||
5543 | ------------------ | |
5544 | -- Get_E_Length -- | |
5545 | ------------------ | |
5546 | ||
5547 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is | |
00c403ee | 5548 | SE : constant Entity_Id := Scope (E); |
ee6ba406 | 5549 | N : Node_Id; |
5550 | E1 : Entity_Id := E; | |
ee6ba406 | 5551 | |
5552 | begin | |
5553 | if Ekind (Scope (E)) = E_Record_Type | |
5554 | and then Has_Discriminants (Scope (E)) | |
5555 | then | |
5556 | N := Build_Discriminal_Subtype_Of_Component (E); | |
5557 | ||
5558 | if Present (N) then | |
5559 | Insert_Action (Ck_Node, N); | |
5560 | E1 := Defining_Identifier (N); | |
5561 | end if; | |
5562 | end if; | |
5563 | ||
5564 | if Ekind (E1) = E_String_Literal_Subtype then | |
5565 | return | |
5566 | Make_Integer_Literal (Loc, | |
5567 | Intval => String_Literal_Length (E1)); | |
5568 | ||
00c403ee | 5569 | elsif SE /= Standard_Standard |
5570 | and then Ekind (Scope (SE)) = E_Protected_Type | |
5571 | and then Has_Discriminants (Scope (SE)) | |
5572 | and then Has_Completion (Scope (SE)) | |
ee6ba406 | 5573 | and then not Inside_Init_Proc |
5574 | then | |
ee6ba406 | 5575 | -- If the type whose length is needed is a private component |
5576 | -- constrained by a discriminant, we must expand the 'Length | |
5577 | -- attribute into an explicit computation, using the discriminal | |
5578 | -- of the current protected operation. This is because the actual | |
5579 | -- type of the prival is constructed after the protected opera- | |
5580 | -- tion has been fully expanded. | |
5581 | ||
5582 | declare | |
5583 | Indx_Type : Node_Id; | |
5584 | Lo : Node_Id; | |
5585 | Hi : Node_Id; | |
5586 | Do_Expand : Boolean := False; | |
5587 | ||
5588 | begin | |
5589 | Indx_Type := First_Index (E); | |
5590 | ||
5591 | for J in 1 .. Indx - 1 loop | |
5592 | Next_Index (Indx_Type); | |
5593 | end loop; | |
5594 | ||
2af58f67 | 5595 | Get_Index_Bounds (Indx_Type, Lo, Hi); |
ee6ba406 | 5596 | |
5597 | if Nkind (Lo) = N_Identifier | |
5598 | and then Ekind (Entity (Lo)) = E_In_Parameter | |
5599 | then | |
5600 | Lo := Get_Discriminal (E, Lo); | |
5601 | Do_Expand := True; | |
5602 | end if; | |
5603 | ||
5604 | if Nkind (Hi) = N_Identifier | |
5605 | and then Ekind (Entity (Hi)) = E_In_Parameter | |
5606 | then | |
5607 | Hi := Get_Discriminal (E, Hi); | |
5608 | Do_Expand := True; | |
5609 | end if; | |
5610 | ||
5611 | if Do_Expand then | |
5612 | if not Is_Entity_Name (Lo) then | |
9dfe12ae | 5613 | Lo := Duplicate_Subexpr_No_Checks (Lo); |
ee6ba406 | 5614 | end if; |
5615 | ||
5616 | if not Is_Entity_Name (Hi) then | |
9dfe12ae | 5617 | Lo := Duplicate_Subexpr_No_Checks (Hi); |
ee6ba406 | 5618 | end if; |
5619 | ||
5620 | N := | |
5621 | Make_Op_Add (Loc, | |
5622 | Left_Opnd => | |
5623 | Make_Op_Subtract (Loc, | |
5624 | Left_Opnd => Hi, | |
5625 | Right_Opnd => Lo), | |
5626 | ||
5627 | Right_Opnd => Make_Integer_Literal (Loc, 1)); | |
5628 | return N; | |
5629 | ||
5630 | else | |
5631 | N := | |
5632 | Make_Attribute_Reference (Loc, | |
5633 | Attribute_Name => Name_Length, | |
5634 | Prefix => | |
5635 | New_Occurrence_Of (E1, Loc)); | |
5636 | ||
5637 | if Indx > 1 then | |
5638 | Set_Expressions (N, New_List ( | |
5639 | Make_Integer_Literal (Loc, Indx))); | |
5640 | end if; | |
5641 | ||
5642 | return N; | |
5643 | end if; | |
5644 | end; | |
5645 | ||
5646 | else | |
5647 | N := | |
5648 | Make_Attribute_Reference (Loc, | |
5649 | Attribute_Name => Name_Length, | |
5650 | Prefix => | |
5651 | New_Occurrence_Of (E1, Loc)); | |
5652 | ||
5653 | if Indx > 1 then | |
5654 | Set_Expressions (N, New_List ( | |
5655 | Make_Integer_Literal (Loc, Indx))); | |
5656 | end if; | |
5657 | ||
5658 | return N; | |
ee6ba406 | 5659 | end if; |
5660 | end Get_E_Length; | |
5661 | ||
5662 | ------------------ | |
5663 | -- Get_N_Length -- | |
5664 | ------------------ | |
5665 | ||
5666 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is | |
5667 | begin | |
5668 | return | |
5669 | Make_Attribute_Reference (Loc, | |
5670 | Attribute_Name => Name_Length, | |
5671 | Prefix => | |
9dfe12ae | 5672 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 5673 | Expressions => New_List ( |
5674 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 5675 | end Get_N_Length; |
5676 | ||
5677 | ------------------- | |
5678 | -- Length_E_Cond -- | |
5679 | ------------------- | |
5680 | ||
5681 | function Length_E_Cond | |
5682 | (Exptyp : Entity_Id; | |
5683 | Typ : Entity_Id; | |
314a23b6 | 5684 | Indx : Nat) return Node_Id |
ee6ba406 | 5685 | is |
5686 | begin | |
5687 | return | |
5688 | Make_Op_Ne (Loc, | |
5689 | Left_Opnd => Get_E_Length (Typ, Indx), | |
5690 | Right_Opnd => Get_E_Length (Exptyp, Indx)); | |
ee6ba406 | 5691 | end Length_E_Cond; |
5692 | ||
5693 | ------------------- | |
5694 | -- Length_N_Cond -- | |
5695 | ------------------- | |
5696 | ||
5697 | function Length_N_Cond | |
5698 | (Expr : Node_Id; | |
5699 | Typ : Entity_Id; | |
314a23b6 | 5700 | Indx : Nat) return Node_Id |
ee6ba406 | 5701 | is |
5702 | begin | |
5703 | return | |
5704 | Make_Op_Ne (Loc, | |
5705 | Left_Opnd => Get_E_Length (Typ, Indx), | |
5706 | Right_Opnd => Get_N_Length (Expr, Indx)); | |
ee6ba406 | 5707 | end Length_N_Cond; |
5708 | ||
feff2f05 | 5709 | ----------------- |
5710 | -- Same_Bounds -- | |
5711 | ----------------- | |
5712 | ||
ee6ba406 | 5713 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is |
5714 | begin | |
5715 | return | |
5716 | (Nkind (L) = N_Integer_Literal | |
5717 | and then Nkind (R) = N_Integer_Literal | |
5718 | and then Intval (L) = Intval (R)) | |
5719 | ||
5720 | or else | |
5721 | (Is_Entity_Name (L) | |
5722 | and then Ekind (Entity (L)) = E_Constant | |
5723 | and then ((Is_Entity_Name (R) | |
5724 | and then Entity (L) = Entity (R)) | |
5725 | or else | |
5726 | (Nkind (R) = N_Type_Conversion | |
5727 | and then Is_Entity_Name (Expression (R)) | |
5728 | and then Entity (L) = Entity (Expression (R))))) | |
5729 | ||
5730 | or else | |
5731 | (Is_Entity_Name (R) | |
5732 | and then Ekind (Entity (R)) = E_Constant | |
5733 | and then Nkind (L) = N_Type_Conversion | |
5734 | and then Is_Entity_Name (Expression (L)) | |
5f260d20 | 5735 | and then Entity (R) = Entity (Expression (L))) |
5736 | ||
5737 | or else | |
5738 | (Is_Entity_Name (L) | |
5739 | and then Is_Entity_Name (R) | |
5740 | and then Entity (L) = Entity (R) | |
5741 | and then Ekind (Entity (L)) = E_In_Parameter | |
5742 | and then Inside_Init_Proc); | |
ee6ba406 | 5743 | end Same_Bounds; |
5744 | ||
5745 | -- Start of processing for Selected_Length_Checks | |
5746 | ||
5747 | begin | |
5748 | if not Expander_Active then | |
5749 | return Ret_Result; | |
5750 | end if; | |
5751 | ||
5752 | if Target_Typ = Any_Type | |
5753 | or else Target_Typ = Any_Composite | |
5754 | or else Raises_Constraint_Error (Ck_Node) | |
5755 | then | |
5756 | return Ret_Result; | |
5757 | end if; | |
5758 | ||
5759 | if No (Wnode) then | |
5760 | Wnode := Ck_Node; | |
5761 | end if; | |
5762 | ||
5763 | T_Typ := Target_Typ; | |
5764 | ||
5765 | if No (Source_Typ) then | |
5766 | S_Typ := Etype (Ck_Node); | |
5767 | else | |
5768 | S_Typ := Source_Typ; | |
5769 | end if; | |
5770 | ||
5771 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
5772 | return Ret_Result; | |
5773 | end if; | |
5774 | ||
5775 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
5776 | S_Typ := Designated_Type (S_Typ); | |
5777 | T_Typ := Designated_Type (T_Typ); | |
5778 | Do_Access := True; | |
5779 | ||
2af58f67 | 5780 | -- A simple optimization for the null case |
ee6ba406 | 5781 | |
2af58f67 | 5782 | if Known_Null (Ck_Node) then |
ee6ba406 | 5783 | return Ret_Result; |
5784 | end if; | |
5785 | end if; | |
5786 | ||
5787 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
5788 | if Is_Constrained (T_Typ) then | |
5789 | ||
5790 | -- The checking code to be generated will freeze the | |
5791 | -- corresponding array type. However, we must freeze the | |
5792 | -- type now, so that the freeze node does not appear within | |
5793 | -- the generated condional expression, but ahead of it. | |
5794 | ||
5795 | Freeze_Before (Ck_Node, T_Typ); | |
5796 | ||
5797 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
84d0d4a5 | 5798 | Exptyp := Get_Actual_Subtype (Ck_Node); |
ee6ba406 | 5799 | |
5800 | if Is_Access_Type (Exptyp) then | |
5801 | Exptyp := Designated_Type (Exptyp); | |
5802 | end if; | |
5803 | ||
5804 | -- String_Literal case. This needs to be handled specially be- | |
5805 | -- cause no index types are available for string literals. The | |
5806 | -- condition is simply: | |
5807 | ||
5808 | -- T_Typ'Length = string-literal-length | |
5809 | ||
9dfe12ae | 5810 | if Nkind (Expr_Actual) = N_String_Literal |
5811 | and then Ekind (Etype (Expr_Actual)) = E_String_Literal_Subtype | |
5812 | then | |
ee6ba406 | 5813 | Cond := |
5814 | Make_Op_Ne (Loc, | |
5815 | Left_Opnd => Get_E_Length (T_Typ, 1), | |
5816 | Right_Opnd => | |
5817 | Make_Integer_Literal (Loc, | |
5818 | Intval => | |
5819 | String_Literal_Length (Etype (Expr_Actual)))); | |
5820 | ||
5821 | -- General array case. Here we have a usable actual subtype for | |
5822 | -- the expression, and the condition is built from the two types | |
5823 | -- (Do_Length): | |
5824 | ||
5825 | -- T_Typ'Length /= Exptyp'Length or else | |
5826 | -- T_Typ'Length (2) /= Exptyp'Length (2) or else | |
5827 | -- T_Typ'Length (3) /= Exptyp'Length (3) or else | |
5828 | -- ... | |
5829 | ||
5830 | elsif Is_Constrained (Exptyp) then | |
5831 | declare | |
9dfe12ae | 5832 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
5833 | ||
5834 | L_Index : Node_Id; | |
5835 | R_Index : Node_Id; | |
5836 | L_Low : Node_Id; | |
5837 | L_High : Node_Id; | |
5838 | R_Low : Node_Id; | |
5839 | R_High : Node_Id; | |
ee6ba406 | 5840 | L_Length : Uint; |
5841 | R_Length : Uint; | |
9dfe12ae | 5842 | Ref_Node : Node_Id; |
ee6ba406 | 5843 | |
5844 | begin | |
feff2f05 | 5845 | -- At the library level, we need to ensure that the type of |
5846 | -- the object is elaborated before the check itself is | |
5847 | -- emitted. This is only done if the object is in the | |
5848 | -- current compilation unit, otherwise the type is frozen | |
5849 | -- and elaborated in its unit. | |
9dfe12ae | 5850 | |
5851 | if Is_Itype (Exptyp) | |
5852 | and then | |
5853 | Ekind (Cunit_Entity (Current_Sem_Unit)) = E_Package | |
5854 | and then | |
5855 | not In_Package_Body (Cunit_Entity (Current_Sem_Unit)) | |
d66aa9f6 | 5856 | and then In_Open_Scopes (Scope (Exptyp)) |
9dfe12ae | 5857 | then |
5858 | Ref_Node := Make_Itype_Reference (Sloc (Ck_Node)); | |
5859 | Set_Itype (Ref_Node, Exptyp); | |
5860 | Insert_Action (Ck_Node, Ref_Node); | |
5861 | end if; | |
5862 | ||
ee6ba406 | 5863 | L_Index := First_Index (T_Typ); |
5864 | R_Index := First_Index (Exptyp); | |
5865 | ||
5866 | for Indx in 1 .. Ndims loop | |
5867 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 5868 | or else |
5869 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 5870 | then |
5871 | Get_Index_Bounds (L_Index, L_Low, L_High); | |
5872 | Get_Index_Bounds (R_Index, R_Low, R_High); | |
5873 | ||
5874 | -- Deal with compile time length check. Note that we | |
5875 | -- skip this in the access case, because the access | |
5876 | -- value may be null, so we cannot know statically. | |
5877 | ||
5878 | if not Do_Access | |
5879 | and then Compile_Time_Known_Value (L_Low) | |
5880 | and then Compile_Time_Known_Value (L_High) | |
5881 | and then Compile_Time_Known_Value (R_Low) | |
5882 | and then Compile_Time_Known_Value (R_High) | |
5883 | then | |
5884 | if Expr_Value (L_High) >= Expr_Value (L_Low) then | |
5885 | L_Length := Expr_Value (L_High) - | |
5886 | Expr_Value (L_Low) + 1; | |
5887 | else | |
5888 | L_Length := UI_From_Int (0); | |
5889 | end if; | |
5890 | ||
5891 | if Expr_Value (R_High) >= Expr_Value (R_Low) then | |
5892 | R_Length := Expr_Value (R_High) - | |
5893 | Expr_Value (R_Low) + 1; | |
5894 | else | |
5895 | R_Length := UI_From_Int (0); | |
5896 | end if; | |
5897 | ||
5898 | if L_Length > R_Length then | |
5899 | Add_Check | |
5900 | (Compile_Time_Constraint_Error | |
5901 | (Wnode, "too few elements for}?", T_Typ)); | |
5902 | ||
5903 | elsif L_Length < R_Length then | |
5904 | Add_Check | |
5905 | (Compile_Time_Constraint_Error | |
5906 | (Wnode, "too many elements for}?", T_Typ)); | |
5907 | end if; | |
5908 | ||
5909 | -- The comparison for an individual index subtype | |
5910 | -- is omitted if the corresponding index subtypes | |
5911 | -- statically match, since the result is known to | |
5912 | -- be true. Note that this test is worth while even | |
5913 | -- though we do static evaluation, because non-static | |
5914 | -- subtypes can statically match. | |
5915 | ||
5916 | elsif not | |
5917 | Subtypes_Statically_Match | |
5918 | (Etype (L_Index), Etype (R_Index)) | |
5919 | ||
5920 | and then not | |
5921 | (Same_Bounds (L_Low, R_Low) | |
5922 | and then Same_Bounds (L_High, R_High)) | |
5923 | then | |
5924 | Evolve_Or_Else | |
5925 | (Cond, Length_E_Cond (Exptyp, T_Typ, Indx)); | |
5926 | end if; | |
5927 | ||
5928 | Next (L_Index); | |
5929 | Next (R_Index); | |
5930 | end if; | |
5931 | end loop; | |
5932 | end; | |
5933 | ||
5934 | -- Handle cases where we do not get a usable actual subtype that | |
5935 | -- is constrained. This happens for example in the function call | |
5936 | -- and explicit dereference cases. In these cases, we have to get | |
5937 | -- the length or range from the expression itself, making sure we | |
5938 | -- do not evaluate it more than once. | |
5939 | ||
5940 | -- Here Ck_Node is the original expression, or more properly the | |
feff2f05 | 5941 | -- result of applying Duplicate_Expr to the original tree, forcing |
5942 | -- the result to be a name. | |
ee6ba406 | 5943 | |
5944 | else | |
5945 | declare | |
9dfe12ae | 5946 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 5947 | |
5948 | begin | |
5949 | -- Build the condition for the explicit dereference case | |
5950 | ||
5951 | for Indx in 1 .. Ndims loop | |
5952 | Evolve_Or_Else | |
5953 | (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx)); | |
5954 | end loop; | |
5955 | end; | |
5956 | end if; | |
5957 | end if; | |
5958 | end if; | |
5959 | ||
5960 | -- Construct the test and insert into the tree | |
5961 | ||
5962 | if Present (Cond) then | |
5963 | if Do_Access then | |
5964 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
5965 | end if; | |
5966 | ||
f15731c4 | 5967 | Add_Check |
5968 | (Make_Raise_Constraint_Error (Loc, | |
5969 | Condition => Cond, | |
5970 | Reason => CE_Length_Check_Failed)); | |
ee6ba406 | 5971 | end if; |
5972 | ||
5973 | return Ret_Result; | |
ee6ba406 | 5974 | end Selected_Length_Checks; |
5975 | ||
5976 | --------------------------- | |
5977 | -- Selected_Range_Checks -- | |
5978 | --------------------------- | |
5979 | ||
5980 | function Selected_Range_Checks | |
5981 | (Ck_Node : Node_Id; | |
5982 | Target_Typ : Entity_Id; | |
5983 | Source_Typ : Entity_Id; | |
314a23b6 | 5984 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 5985 | is |
5986 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
5987 | S_Typ : Entity_Id; | |
5988 | T_Typ : Entity_Id; | |
5989 | Expr_Actual : Node_Id; | |
5990 | Exptyp : Entity_Id; | |
5991 | Cond : Node_Id := Empty; | |
5992 | Do_Access : Boolean := False; | |
5993 | Wnode : Node_Id := Warn_Node; | |
5994 | Ret_Result : Check_Result := (Empty, Empty); | |
5995 | Num_Checks : Integer := 0; | |
5996 | ||
5997 | procedure Add_Check (N : Node_Id); | |
5998 | -- Adds the action given to Ret_Result if N is non-Empty | |
5999 | ||
6000 | function Discrete_Range_Cond | |
6001 | (Expr : Node_Id; | |
314a23b6 | 6002 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 6003 | -- Returns expression to compute: |
6004 | -- Low_Bound (Expr) < Typ'First | |
6005 | -- or else | |
6006 | -- High_Bound (Expr) > Typ'Last | |
6007 | ||
6008 | function Discrete_Expr_Cond | |
6009 | (Expr : Node_Id; | |
314a23b6 | 6010 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 6011 | -- Returns expression to compute: |
6012 | -- Expr < Typ'First | |
6013 | -- or else | |
6014 | -- Expr > Typ'Last | |
6015 | ||
6016 | function Get_E_First_Or_Last | |
6017 | (E : Entity_Id; | |
6018 | Indx : Nat; | |
314a23b6 | 6019 | Nam : Name_Id) return Node_Id; |
ee6ba406 | 6020 | -- Returns expression to compute: |
6021 | -- E'First or E'Last | |
6022 | ||
6023 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id; | |
6024 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id; | |
6025 | -- Returns expression to compute: | |
9dfe12ae | 6026 | -- N'First or N'Last using Duplicate_Subexpr_No_Checks |
ee6ba406 | 6027 | |
6028 | function Range_E_Cond | |
6029 | (Exptyp : Entity_Id; | |
6030 | Typ : Entity_Id; | |
6031 | Indx : Nat) | |
6032 | return Node_Id; | |
6033 | -- Returns expression to compute: | |
6034 | -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last | |
6035 | ||
6036 | function Range_Equal_E_Cond | |
6037 | (Exptyp : Entity_Id; | |
6038 | Typ : Entity_Id; | |
314a23b6 | 6039 | Indx : Nat) return Node_Id; |
ee6ba406 | 6040 | -- Returns expression to compute: |
6041 | -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last | |
6042 | ||
6043 | function Range_N_Cond | |
6044 | (Expr : Node_Id; | |
6045 | Typ : Entity_Id; | |
314a23b6 | 6046 | Indx : Nat) return Node_Id; |
ee6ba406 | 6047 | -- Return expression to compute: |
6048 | -- Expr'First < Typ'First or else Expr'Last > Typ'Last | |
6049 | ||
6050 | --------------- | |
6051 | -- Add_Check -- | |
6052 | --------------- | |
6053 | ||
6054 | procedure Add_Check (N : Node_Id) is | |
6055 | begin | |
6056 | if Present (N) then | |
6057 | ||
6058 | -- For now, ignore attempt to place more than 2 checks ??? | |
6059 | ||
6060 | if Num_Checks = 2 then | |
6061 | return; | |
6062 | end if; | |
6063 | ||
6064 | pragma Assert (Num_Checks <= 1); | |
6065 | Num_Checks := Num_Checks + 1; | |
6066 | Ret_Result (Num_Checks) := N; | |
6067 | end if; | |
6068 | end Add_Check; | |
6069 | ||
6070 | ------------------------- | |
6071 | -- Discrete_Expr_Cond -- | |
6072 | ------------------------- | |
6073 | ||
6074 | function Discrete_Expr_Cond | |
6075 | (Expr : Node_Id; | |
314a23b6 | 6076 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 6077 | is |
6078 | begin | |
6079 | return | |
6080 | Make_Or_Else (Loc, | |
6081 | Left_Opnd => | |
6082 | Make_Op_Lt (Loc, | |
6083 | Left_Opnd => | |
9dfe12ae | 6084 | Convert_To (Base_Type (Typ), |
6085 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 6086 | Right_Opnd => |
6087 | Convert_To (Base_Type (Typ), | |
6088 | Get_E_First_Or_Last (Typ, 0, Name_First))), | |
6089 | ||
6090 | Right_Opnd => | |
6091 | Make_Op_Gt (Loc, | |
6092 | Left_Opnd => | |
9dfe12ae | 6093 | Convert_To (Base_Type (Typ), |
6094 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 6095 | Right_Opnd => |
6096 | Convert_To | |
6097 | (Base_Type (Typ), | |
6098 | Get_E_First_Or_Last (Typ, 0, Name_Last)))); | |
6099 | end Discrete_Expr_Cond; | |
6100 | ||
6101 | ------------------------- | |
6102 | -- Discrete_Range_Cond -- | |
6103 | ------------------------- | |
6104 | ||
6105 | function Discrete_Range_Cond | |
6106 | (Expr : Node_Id; | |
314a23b6 | 6107 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 6108 | is |
6109 | LB : Node_Id := Low_Bound (Expr); | |
6110 | HB : Node_Id := High_Bound (Expr); | |
6111 | ||
6112 | Left_Opnd : Node_Id; | |
6113 | Right_Opnd : Node_Id; | |
6114 | ||
6115 | begin | |
6116 | if Nkind (LB) = N_Identifier | |
feff2f05 | 6117 | and then Ekind (Entity (LB)) = E_Discriminant |
6118 | then | |
ee6ba406 | 6119 | LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc); |
6120 | end if; | |
6121 | ||
6122 | if Nkind (HB) = N_Identifier | |
feff2f05 | 6123 | and then Ekind (Entity (HB)) = E_Discriminant |
6124 | then | |
ee6ba406 | 6125 | HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc); |
6126 | end if; | |
6127 | ||
6128 | Left_Opnd := | |
6129 | Make_Op_Lt (Loc, | |
6130 | Left_Opnd => | |
6131 | Convert_To | |
9dfe12ae | 6132 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (LB)), |
ee6ba406 | 6133 | |
6134 | Right_Opnd => | |
6135 | Convert_To | |
6136 | (Base_Type (Typ), Get_E_First_Or_Last (Typ, 0, Name_First))); | |
6137 | ||
6138 | if Base_Type (Typ) = Typ then | |
6139 | return Left_Opnd; | |
6140 | ||
6141 | elsif Compile_Time_Known_Value (High_Bound (Scalar_Range (Typ))) | |
6142 | and then | |
6143 | Compile_Time_Known_Value (High_Bound (Scalar_Range | |
6144 | (Base_Type (Typ)))) | |
6145 | then | |
6146 | if Is_Floating_Point_Type (Typ) then | |
6147 | if Expr_Value_R (High_Bound (Scalar_Range (Typ))) = | |
6148 | Expr_Value_R (High_Bound (Scalar_Range (Base_Type (Typ)))) | |
6149 | then | |
6150 | return Left_Opnd; | |
6151 | end if; | |
6152 | ||
6153 | else | |
6154 | if Expr_Value (High_Bound (Scalar_Range (Typ))) = | |
6155 | Expr_Value (High_Bound (Scalar_Range (Base_Type (Typ)))) | |
6156 | then | |
6157 | return Left_Opnd; | |
6158 | end if; | |
6159 | end if; | |
6160 | end if; | |
6161 | ||
6162 | Right_Opnd := | |
6163 | Make_Op_Gt (Loc, | |
6164 | Left_Opnd => | |
6165 | Convert_To | |
9dfe12ae | 6166 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (HB)), |
ee6ba406 | 6167 | |
6168 | Right_Opnd => | |
6169 | Convert_To | |
6170 | (Base_Type (Typ), | |
6171 | Get_E_First_Or_Last (Typ, 0, Name_Last))); | |
6172 | ||
6173 | return Make_Or_Else (Loc, Left_Opnd, Right_Opnd); | |
6174 | end Discrete_Range_Cond; | |
6175 | ||
6176 | ------------------------- | |
6177 | -- Get_E_First_Or_Last -- | |
6178 | ------------------------- | |
6179 | ||
6180 | function Get_E_First_Or_Last | |
6181 | (E : Entity_Id; | |
6182 | Indx : Nat; | |
314a23b6 | 6183 | Nam : Name_Id) return Node_Id |
ee6ba406 | 6184 | is |
6185 | N : Node_Id; | |
6186 | LB : Node_Id; | |
6187 | HB : Node_Id; | |
6188 | Bound : Node_Id; | |
6189 | ||
6190 | begin | |
6191 | if Is_Array_Type (E) then | |
6192 | N := First_Index (E); | |
6193 | ||
6194 | for J in 2 .. Indx loop | |
6195 | Next_Index (N); | |
6196 | end loop; | |
6197 | ||
6198 | else | |
6199 | N := Scalar_Range (E); | |
6200 | end if; | |
6201 | ||
6202 | if Nkind (N) = N_Subtype_Indication then | |
6203 | LB := Low_Bound (Range_Expression (Constraint (N))); | |
6204 | HB := High_Bound (Range_Expression (Constraint (N))); | |
6205 | ||
6206 | elsif Is_Entity_Name (N) then | |
6207 | LB := Type_Low_Bound (Etype (N)); | |
6208 | HB := Type_High_Bound (Etype (N)); | |
6209 | ||
6210 | else | |
6211 | LB := Low_Bound (N); | |
6212 | HB := High_Bound (N); | |
6213 | end if; | |
6214 | ||
6215 | if Nam = Name_First then | |
6216 | Bound := LB; | |
6217 | else | |
6218 | Bound := HB; | |
6219 | end if; | |
6220 | ||
6221 | if Nkind (Bound) = N_Identifier | |
6222 | and then Ekind (Entity (Bound)) = E_Discriminant | |
6223 | then | |
9dfe12ae | 6224 | -- If this is a task discriminant, and we are the body, we must |
6225 | -- retrieve the corresponding body discriminal. This is another | |
6226 | -- consequence of the early creation of discriminals, and the | |
6227 | -- need to generate constraint checks before their declarations | |
6228 | -- are made visible. | |
6229 | ||
6230 | if Is_Concurrent_Record_Type (Scope (Entity (Bound))) then | |
6231 | declare | |
6232 | Tsk : constant Entity_Id := | |
6233 | Corresponding_Concurrent_Type | |
6234 | (Scope (Entity (Bound))); | |
6235 | Disc : Entity_Id; | |
6236 | ||
6237 | begin | |
6238 | if In_Open_Scopes (Tsk) | |
6239 | and then Has_Completion (Tsk) | |
6240 | then | |
6241 | -- Find discriminant of original task, and use its | |
6242 | -- current discriminal, which is the renaming within | |
6243 | -- the task body. | |
6244 | ||
6245 | Disc := First_Discriminant (Tsk); | |
6246 | while Present (Disc) loop | |
6247 | if Chars (Disc) = Chars (Entity (Bound)) then | |
6248 | Set_Scope (Discriminal (Disc), Tsk); | |
6249 | return New_Occurrence_Of (Discriminal (Disc), Loc); | |
6250 | end if; | |
6251 | ||
6252 | Next_Discriminant (Disc); | |
6253 | end loop; | |
6254 | ||
6255 | -- That loop should always succeed in finding a matching | |
6256 | -- entry and returning. Fatal error if not. | |
6257 | ||
6258 | raise Program_Error; | |
6259 | ||
6260 | else | |
6261 | return | |
6262 | New_Occurrence_Of (Discriminal (Entity (Bound)), Loc); | |
6263 | end if; | |
6264 | end; | |
6265 | else | |
6266 | return New_Occurrence_Of (Discriminal (Entity (Bound)), Loc); | |
6267 | end if; | |
ee6ba406 | 6268 | |
6269 | elsif Nkind (Bound) = N_Identifier | |
6270 | and then Ekind (Entity (Bound)) = E_In_Parameter | |
6271 | and then not Inside_Init_Proc | |
6272 | then | |
6273 | return Get_Discriminal (E, Bound); | |
6274 | ||
6275 | elsif Nkind (Bound) = N_Integer_Literal then | |
18563cef | 6276 | return Make_Integer_Literal (Loc, Intval (Bound)); |
6277 | ||
feff2f05 | 6278 | -- Case of a bound rewritten to an N_Raise_Constraint_Error node |
6279 | -- because it is an out-of-range value. Duplicate_Subexpr cannot be | |
6280 | -- called on this node because an N_Raise_Constraint_Error is not | |
6281 | -- side effect free, and we may not assume that we are in the proper | |
6282 | -- context to remove side effects on it at the point of reference. | |
18563cef | 6283 | |
6284 | elsif Nkind (Bound) = N_Raise_Constraint_Error then | |
6285 | return New_Copy_Tree (Bound); | |
ee6ba406 | 6286 | |
6287 | else | |
9dfe12ae | 6288 | return Duplicate_Subexpr_No_Checks (Bound); |
ee6ba406 | 6289 | end if; |
6290 | end Get_E_First_Or_Last; | |
6291 | ||
6292 | ----------------- | |
6293 | -- Get_N_First -- | |
6294 | ----------------- | |
6295 | ||
6296 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is | |
6297 | begin | |
6298 | return | |
6299 | Make_Attribute_Reference (Loc, | |
6300 | Attribute_Name => Name_First, | |
6301 | Prefix => | |
9dfe12ae | 6302 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 6303 | Expressions => New_List ( |
6304 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 6305 | end Get_N_First; |
6306 | ||
6307 | ---------------- | |
6308 | -- Get_N_Last -- | |
6309 | ---------------- | |
6310 | ||
6311 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is | |
6312 | begin | |
6313 | return | |
6314 | Make_Attribute_Reference (Loc, | |
6315 | Attribute_Name => Name_Last, | |
6316 | Prefix => | |
9dfe12ae | 6317 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 6318 | Expressions => New_List ( |
6319 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 6320 | end Get_N_Last; |
6321 | ||
6322 | ------------------ | |
6323 | -- Range_E_Cond -- | |
6324 | ------------------ | |
6325 | ||
6326 | function Range_E_Cond | |
6327 | (Exptyp : Entity_Id; | |
6328 | Typ : Entity_Id; | |
314a23b6 | 6329 | Indx : Nat) return Node_Id |
ee6ba406 | 6330 | is |
6331 | begin | |
6332 | return | |
6333 | Make_Or_Else (Loc, | |
6334 | Left_Opnd => | |
6335 | Make_Op_Lt (Loc, | |
6336 | Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_First), | |
6337 | Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)), | |
6338 | ||
6339 | Right_Opnd => | |
6340 | Make_Op_Gt (Loc, | |
6341 | Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_Last), | |
6342 | Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last))); | |
ee6ba406 | 6343 | end Range_E_Cond; |
6344 | ||
6345 | ------------------------ | |
6346 | -- Range_Equal_E_Cond -- | |
6347 | ------------------------ | |
6348 | ||
6349 | function Range_Equal_E_Cond | |
6350 | (Exptyp : Entity_Id; | |
6351 | Typ : Entity_Id; | |
314a23b6 | 6352 | Indx : Nat) return Node_Id |
ee6ba406 | 6353 | is |
6354 | begin | |
6355 | return | |
6356 | Make_Or_Else (Loc, | |
6357 | Left_Opnd => | |
6358 | Make_Op_Ne (Loc, | |
6359 | Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_First), | |
6360 | Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)), | |
6361 | Right_Opnd => | |
6362 | Make_Op_Ne (Loc, | |
6363 | Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_Last), | |
6364 | Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last))); | |
6365 | end Range_Equal_E_Cond; | |
6366 | ||
6367 | ------------------ | |
6368 | -- Range_N_Cond -- | |
6369 | ------------------ | |
6370 | ||
6371 | function Range_N_Cond | |
6372 | (Expr : Node_Id; | |
6373 | Typ : Entity_Id; | |
314a23b6 | 6374 | Indx : Nat) return Node_Id |
ee6ba406 | 6375 | is |
6376 | begin | |
6377 | return | |
6378 | Make_Or_Else (Loc, | |
6379 | Left_Opnd => | |
6380 | Make_Op_Lt (Loc, | |
6381 | Left_Opnd => Get_N_First (Expr, Indx), | |
6382 | Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)), | |
6383 | ||
6384 | Right_Opnd => | |
6385 | Make_Op_Gt (Loc, | |
6386 | Left_Opnd => Get_N_Last (Expr, Indx), | |
6387 | Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last))); | |
6388 | end Range_N_Cond; | |
6389 | ||
6390 | -- Start of processing for Selected_Range_Checks | |
6391 | ||
6392 | begin | |
6393 | if not Expander_Active then | |
6394 | return Ret_Result; | |
6395 | end if; | |
6396 | ||
6397 | if Target_Typ = Any_Type | |
6398 | or else Target_Typ = Any_Composite | |
6399 | or else Raises_Constraint_Error (Ck_Node) | |
6400 | then | |
6401 | return Ret_Result; | |
6402 | end if; | |
6403 | ||
6404 | if No (Wnode) then | |
6405 | Wnode := Ck_Node; | |
6406 | end if; | |
6407 | ||
6408 | T_Typ := Target_Typ; | |
6409 | ||
6410 | if No (Source_Typ) then | |
6411 | S_Typ := Etype (Ck_Node); | |
6412 | else | |
6413 | S_Typ := Source_Typ; | |
6414 | end if; | |
6415 | ||
6416 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
6417 | return Ret_Result; | |
6418 | end if; | |
6419 | ||
6420 | -- The order of evaluating T_Typ before S_Typ seems to be critical | |
6421 | -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed | |
6422 | -- in, and since Node can be an N_Range node, it might be invalid. | |
6423 | -- Should there be an assert check somewhere for taking the Etype of | |
6424 | -- an N_Range node ??? | |
6425 | ||
6426 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
6427 | S_Typ := Designated_Type (S_Typ); | |
6428 | T_Typ := Designated_Type (T_Typ); | |
6429 | Do_Access := True; | |
6430 | ||
2af58f67 | 6431 | -- A simple optimization for the null case |
ee6ba406 | 6432 | |
2af58f67 | 6433 | if Known_Null (Ck_Node) then |
ee6ba406 | 6434 | return Ret_Result; |
6435 | end if; | |
6436 | end if; | |
6437 | ||
6438 | -- For an N_Range Node, check for a null range and then if not | |
6439 | -- null generate a range check action. | |
6440 | ||
6441 | if Nkind (Ck_Node) = N_Range then | |
6442 | ||
6443 | -- There's no point in checking a range against itself | |
6444 | ||
6445 | if Ck_Node = Scalar_Range (T_Typ) then | |
6446 | return Ret_Result; | |
6447 | end if; | |
6448 | ||
6449 | declare | |
6450 | T_LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
6451 | T_HB : constant Node_Id := Type_High_Bound (T_Typ); | |
6452 | LB : constant Node_Id := Low_Bound (Ck_Node); | |
6453 | HB : constant Node_Id := High_Bound (Ck_Node); | |
6454 | Null_Range : Boolean; | |
6455 | ||
6456 | Out_Of_Range_L : Boolean; | |
6457 | Out_Of_Range_H : Boolean; | |
6458 | ||
6459 | begin | |
6460 | -- Check for case where everything is static and we can | |
6461 | -- do the check at compile time. This is skipped if we | |
6462 | -- have an access type, since the access value may be null. | |
6463 | ||
6464 | -- ??? This code can be improved since you only need to know | |
6465 | -- that the two respective bounds (LB & T_LB or HB & T_HB) | |
6466 | -- are known at compile time to emit pertinent messages. | |
6467 | ||
6468 | if Compile_Time_Known_Value (LB) | |
6469 | and then Compile_Time_Known_Value (HB) | |
6470 | and then Compile_Time_Known_Value (T_LB) | |
6471 | and then Compile_Time_Known_Value (T_HB) | |
6472 | and then not Do_Access | |
6473 | then | |
6474 | -- Floating-point case | |
6475 | ||
6476 | if Is_Floating_Point_Type (S_Typ) then | |
6477 | Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB); | |
6478 | Out_Of_Range_L := | |
6479 | (Expr_Value_R (LB) < Expr_Value_R (T_LB)) | |
6480 | or else | |
6481 | (Expr_Value_R (LB) > Expr_Value_R (T_HB)); | |
6482 | ||
6483 | Out_Of_Range_H := | |
6484 | (Expr_Value_R (HB) > Expr_Value_R (T_HB)) | |
6485 | or else | |
6486 | (Expr_Value_R (HB) < Expr_Value_R (T_LB)); | |
6487 | ||
6488 | -- Fixed or discrete type case | |
6489 | ||
6490 | else | |
6491 | Null_Range := Expr_Value (HB) < Expr_Value (LB); | |
6492 | Out_Of_Range_L := | |
6493 | (Expr_Value (LB) < Expr_Value (T_LB)) | |
6494 | or else | |
6495 | (Expr_Value (LB) > Expr_Value (T_HB)); | |
6496 | ||
6497 | Out_Of_Range_H := | |
6498 | (Expr_Value (HB) > Expr_Value (T_HB)) | |
6499 | or else | |
6500 | (Expr_Value (HB) < Expr_Value (T_LB)); | |
6501 | end if; | |
6502 | ||
6503 | if not Null_Range then | |
6504 | if Out_Of_Range_L then | |
6505 | if No (Warn_Node) then | |
6506 | Add_Check | |
6507 | (Compile_Time_Constraint_Error | |
6508 | (Low_Bound (Ck_Node), | |
6509 | "static value out of range of}?", T_Typ)); | |
6510 | ||
6511 | else | |
6512 | Add_Check | |
6513 | (Compile_Time_Constraint_Error | |
6514 | (Wnode, | |
6515 | "static range out of bounds of}?", T_Typ)); | |
6516 | end if; | |
6517 | end if; | |
6518 | ||
6519 | if Out_Of_Range_H then | |
6520 | if No (Warn_Node) then | |
6521 | Add_Check | |
6522 | (Compile_Time_Constraint_Error | |
6523 | (High_Bound (Ck_Node), | |
6524 | "static value out of range of}?", T_Typ)); | |
6525 | ||
6526 | else | |
6527 | Add_Check | |
6528 | (Compile_Time_Constraint_Error | |
6529 | (Wnode, | |
6530 | "static range out of bounds of}?", T_Typ)); | |
6531 | end if; | |
6532 | end if; | |
6533 | ||
6534 | end if; | |
6535 | ||
6536 | else | |
6537 | declare | |
6538 | LB : Node_Id := Low_Bound (Ck_Node); | |
6539 | HB : Node_Id := High_Bound (Ck_Node); | |
6540 | ||
6541 | begin | |
feff2f05 | 6542 | -- If either bound is a discriminant and we are within the |
6543 | -- record declaration, it is a use of the discriminant in a | |
6544 | -- constraint of a component, and nothing can be checked | |
6545 | -- here. The check will be emitted within the init proc. | |
6546 | -- Before then, the discriminal has no real meaning. | |
6547 | -- Similarly, if the entity is a discriminal, there is no | |
6548 | -- check to perform yet. | |
6549 | ||
6550 | -- The same holds within a discriminated synchronized type, | |
6551 | -- where the discriminant may constrain a component or an | |
6552 | -- entry family. | |
ee6ba406 | 6553 | |
6554 | if Nkind (LB) = N_Identifier | |
0577b0b1 | 6555 | and then Denotes_Discriminant (LB, True) |
ee6ba406 | 6556 | then |
0577b0b1 | 6557 | if Current_Scope = Scope (Entity (LB)) |
6558 | or else Is_Concurrent_Type (Current_Scope) | |
6559 | or else Ekind (Entity (LB)) /= E_Discriminant | |
6560 | then | |
ee6ba406 | 6561 | return Ret_Result; |
6562 | else | |
6563 | LB := | |
6564 | New_Occurrence_Of (Discriminal (Entity (LB)), Loc); | |
6565 | end if; | |
6566 | end if; | |
6567 | ||
6568 | if Nkind (HB) = N_Identifier | |
0577b0b1 | 6569 | and then Denotes_Discriminant (HB, True) |
ee6ba406 | 6570 | then |
0577b0b1 | 6571 | if Current_Scope = Scope (Entity (HB)) |
6572 | or else Is_Concurrent_Type (Current_Scope) | |
6573 | or else Ekind (Entity (HB)) /= E_Discriminant | |
6574 | then | |
ee6ba406 | 6575 | return Ret_Result; |
6576 | else | |
6577 | HB := | |
6578 | New_Occurrence_Of (Discriminal (Entity (HB)), Loc); | |
6579 | end if; | |
6580 | end if; | |
6581 | ||
6582 | Cond := Discrete_Range_Cond (Ck_Node, T_Typ); | |
6583 | Set_Paren_Count (Cond, 1); | |
6584 | ||
6585 | Cond := | |
6586 | Make_And_Then (Loc, | |
6587 | Left_Opnd => | |
6588 | Make_Op_Ge (Loc, | |
9dfe12ae | 6589 | Left_Opnd => Duplicate_Subexpr_No_Checks (HB), |
6590 | Right_Opnd => Duplicate_Subexpr_No_Checks (LB)), | |
ee6ba406 | 6591 | Right_Opnd => Cond); |
6592 | end; | |
ee6ba406 | 6593 | end if; |
6594 | end; | |
6595 | ||
6596 | elsif Is_Scalar_Type (S_Typ) then | |
6597 | ||
6598 | -- This somewhat duplicates what Apply_Scalar_Range_Check does, | |
6599 | -- except the above simply sets a flag in the node and lets | |
6600 | -- gigi generate the check base on the Etype of the expression. | |
6601 | -- Sometimes, however we want to do a dynamic check against an | |
6602 | -- arbitrary target type, so we do that here. | |
6603 | ||
6604 | if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then | |
6605 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
6606 | ||
6607 | -- For literals, we can tell if the constraint error will be | |
6608 | -- raised at compile time, so we never need a dynamic check, but | |
6609 | -- if the exception will be raised, then post the usual warning, | |
6610 | -- and replace the literal with a raise constraint error | |
6611 | -- expression. As usual, skip this for access types | |
6612 | ||
6613 | elsif Compile_Time_Known_Value (Ck_Node) | |
6614 | and then not Do_Access | |
6615 | then | |
6616 | declare | |
6617 | LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
6618 | UB : constant Node_Id := Type_High_Bound (T_Typ); | |
6619 | ||
6620 | Out_Of_Range : Boolean; | |
6621 | Static_Bounds : constant Boolean := | |
6622 | Compile_Time_Known_Value (LB) | |
6623 | and Compile_Time_Known_Value (UB); | |
6624 | ||
6625 | begin | |
6626 | -- Following range tests should use Sem_Eval routine ??? | |
6627 | ||
6628 | if Static_Bounds then | |
6629 | if Is_Floating_Point_Type (S_Typ) then | |
6630 | Out_Of_Range := | |
6631 | (Expr_Value_R (Ck_Node) < Expr_Value_R (LB)) | |
6632 | or else | |
6633 | (Expr_Value_R (Ck_Node) > Expr_Value_R (UB)); | |
6634 | ||
6635 | else -- fixed or discrete type | |
6636 | Out_Of_Range := | |
6637 | Expr_Value (Ck_Node) < Expr_Value (LB) | |
6638 | or else | |
6639 | Expr_Value (Ck_Node) > Expr_Value (UB); | |
6640 | end if; | |
6641 | ||
6642 | -- Bounds of the type are static and the literal is | |
6643 | -- out of range so make a warning message. | |
6644 | ||
6645 | if Out_Of_Range then | |
6646 | if No (Warn_Node) then | |
6647 | Add_Check | |
6648 | (Compile_Time_Constraint_Error | |
6649 | (Ck_Node, | |
6650 | "static value out of range of}?", T_Typ)); | |
6651 | ||
6652 | else | |
6653 | Add_Check | |
6654 | (Compile_Time_Constraint_Error | |
6655 | (Wnode, | |
6656 | "static value out of range of}?", T_Typ)); | |
6657 | end if; | |
6658 | end if; | |
6659 | ||
6660 | else | |
6661 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
6662 | end if; | |
6663 | end; | |
6664 | ||
6665 | -- Here for the case of a non-static expression, we need a runtime | |
6666 | -- check unless the source type range is guaranteed to be in the | |
6667 | -- range of the target type. | |
6668 | ||
6669 | else | |
6670 | if not In_Subrange_Of (S_Typ, T_Typ) then | |
6671 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
6672 | end if; | |
6673 | end if; | |
6674 | end if; | |
6675 | ||
6676 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
6677 | if Is_Constrained (T_Typ) then | |
6678 | ||
6679 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
6680 | Exptyp := Get_Actual_Subtype (Expr_Actual); | |
6681 | ||
6682 | if Is_Access_Type (Exptyp) then | |
6683 | Exptyp := Designated_Type (Exptyp); | |
6684 | end if; | |
6685 | ||
6686 | -- String_Literal case. This needs to be handled specially be- | |
6687 | -- cause no index types are available for string literals. The | |
6688 | -- condition is simply: | |
6689 | ||
6690 | -- T_Typ'Length = string-literal-length | |
6691 | ||
6692 | if Nkind (Expr_Actual) = N_String_Literal then | |
6693 | null; | |
6694 | ||
6695 | -- General array case. Here we have a usable actual subtype for | |
6696 | -- the expression, and the condition is built from the two types | |
6697 | ||
6698 | -- T_Typ'First < Exptyp'First or else | |
6699 | -- T_Typ'Last > Exptyp'Last or else | |
6700 | -- T_Typ'First(1) < Exptyp'First(1) or else | |
6701 | -- T_Typ'Last(1) > Exptyp'Last(1) or else | |
6702 | -- ... | |
6703 | ||
6704 | elsif Is_Constrained (Exptyp) then | |
6705 | declare | |
9dfe12ae | 6706 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
6707 | ||
ee6ba406 | 6708 | L_Index : Node_Id; |
6709 | R_Index : Node_Id; | |
ee6ba406 | 6710 | |
6711 | begin | |
6712 | L_Index := First_Index (T_Typ); | |
6713 | R_Index := First_Index (Exptyp); | |
6714 | ||
6715 | for Indx in 1 .. Ndims loop | |
6716 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 6717 | or else |
6718 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 6719 | then |
ee6ba406 | 6720 | -- Deal with compile time length check. Note that we |
6721 | -- skip this in the access case, because the access | |
6722 | -- value may be null, so we cannot know statically. | |
6723 | ||
6724 | if not | |
6725 | Subtypes_Statically_Match | |
6726 | (Etype (L_Index), Etype (R_Index)) | |
6727 | then | |
6728 | -- If the target type is constrained then we | |
6729 | -- have to check for exact equality of bounds | |
6730 | -- (required for qualified expressions). | |
6731 | ||
6732 | if Is_Constrained (T_Typ) then | |
6733 | Evolve_Or_Else | |
6734 | (Cond, | |
6735 | Range_Equal_E_Cond (Exptyp, T_Typ, Indx)); | |
ee6ba406 | 6736 | else |
6737 | Evolve_Or_Else | |
6738 | (Cond, Range_E_Cond (Exptyp, T_Typ, Indx)); | |
6739 | end if; | |
6740 | end if; | |
6741 | ||
6742 | Next (L_Index); | |
6743 | Next (R_Index); | |
6744 | ||
6745 | end if; | |
6746 | end loop; | |
6747 | end; | |
6748 | ||
6749 | -- Handle cases where we do not get a usable actual subtype that | |
6750 | -- is constrained. This happens for example in the function call | |
6751 | -- and explicit dereference cases. In these cases, we have to get | |
6752 | -- the length or range from the expression itself, making sure we | |
6753 | -- do not evaluate it more than once. | |
6754 | ||
6755 | -- Here Ck_Node is the original expression, or more properly the | |
6756 | -- result of applying Duplicate_Expr to the original tree, | |
6757 | -- forcing the result to be a name. | |
6758 | ||
6759 | else | |
6760 | declare | |
9dfe12ae | 6761 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 6762 | |
6763 | begin | |
6764 | -- Build the condition for the explicit dereference case | |
6765 | ||
6766 | for Indx in 1 .. Ndims loop | |
6767 | Evolve_Or_Else | |
6768 | (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx)); | |
6769 | end loop; | |
6770 | end; | |
6771 | ||
6772 | end if; | |
6773 | ||
6774 | else | |
feff2f05 | 6775 | -- For a conversion to an unconstrained array type, generate an |
6776 | -- Action to check that the bounds of the source value are within | |
6777 | -- the constraints imposed by the target type (RM 4.6(38)). No | |
6778 | -- check is needed for a conversion to an access to unconstrained | |
6779 | -- array type, as 4.6(24.15/2) requires the designated subtypes | |
6780 | -- of the two access types to statically match. | |
6781 | ||
6782 | if Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
6783 | and then not Do_Access | |
6784 | then | |
ee6ba406 | 6785 | declare |
6786 | Opnd_Index : Node_Id; | |
6787 | Targ_Index : Node_Id; | |
00c403ee | 6788 | Opnd_Range : Node_Id; |
ee6ba406 | 6789 | |
6790 | begin | |
feff2f05 | 6791 | Opnd_Index := First_Index (Get_Actual_Subtype (Ck_Node)); |
ee6ba406 | 6792 | Targ_Index := First_Index (T_Typ); |
00c403ee | 6793 | |
6794 | while Present (Opnd_Index) loop | |
6795 | ||
6796 | -- If the index is a range, use its bounds. If it is an | |
6797 | -- entity (as will be the case if it is a named subtype | |
6798 | -- or an itype created for a slice) retrieve its range. | |
6799 | ||
6800 | if Is_Entity_Name (Opnd_Index) | |
6801 | and then Is_Type (Entity (Opnd_Index)) | |
6802 | then | |
6803 | Opnd_Range := Scalar_Range (Entity (Opnd_Index)); | |
6804 | else | |
6805 | Opnd_Range := Opnd_Index; | |
6806 | end if; | |
6807 | ||
6808 | if Nkind (Opnd_Range) = N_Range then | |
ee6ba406 | 6809 | if Is_In_Range |
00c403ee | 6810 | (Low_Bound (Opnd_Range), Etype (Targ_Index)) |
ee6ba406 | 6811 | and then |
6812 | Is_In_Range | |
00c403ee | 6813 | (High_Bound (Opnd_Range), Etype (Targ_Index)) |
ee6ba406 | 6814 | then |
6815 | null; | |
6816 | ||
feff2f05 | 6817 | -- If null range, no check needed |
f2a06be9 | 6818 | |
9dfe12ae | 6819 | elsif |
00c403ee | 6820 | Compile_Time_Known_Value (High_Bound (Opnd_Range)) |
9dfe12ae | 6821 | and then |
00c403ee | 6822 | Compile_Time_Known_Value (Low_Bound (Opnd_Range)) |
9dfe12ae | 6823 | and then |
00c403ee | 6824 | Expr_Value (High_Bound (Opnd_Range)) < |
6825 | Expr_Value (Low_Bound (Opnd_Range)) | |
9dfe12ae | 6826 | then |
6827 | null; | |
6828 | ||
ee6ba406 | 6829 | elsif Is_Out_Of_Range |
00c403ee | 6830 | (Low_Bound (Opnd_Range), Etype (Targ_Index)) |
ee6ba406 | 6831 | or else |
6832 | Is_Out_Of_Range | |
00c403ee | 6833 | (High_Bound (Opnd_Range), Etype (Targ_Index)) |
ee6ba406 | 6834 | then |
6835 | Add_Check | |
6836 | (Compile_Time_Constraint_Error | |
6837 | (Wnode, "value out of range of}?", T_Typ)); | |
6838 | ||
6839 | else | |
6840 | Evolve_Or_Else | |
6841 | (Cond, | |
6842 | Discrete_Range_Cond | |
00c403ee | 6843 | (Opnd_Range, Etype (Targ_Index))); |
ee6ba406 | 6844 | end if; |
6845 | end if; | |
6846 | ||
6847 | Next_Index (Opnd_Index); | |
6848 | Next_Index (Targ_Index); | |
6849 | end loop; | |
6850 | end; | |
6851 | end if; | |
6852 | end if; | |
6853 | end if; | |
6854 | ||
6855 | -- Construct the test and insert into the tree | |
6856 | ||
6857 | if Present (Cond) then | |
6858 | if Do_Access then | |
6859 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
6860 | end if; | |
6861 | ||
f15731c4 | 6862 | Add_Check |
6863 | (Make_Raise_Constraint_Error (Loc, | |
6864 | Condition => Cond, | |
6865 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 6866 | end if; |
6867 | ||
6868 | return Ret_Result; | |
ee6ba406 | 6869 | end Selected_Range_Checks; |
6870 | ||
6871 | ------------------------------- | |
6872 | -- Storage_Checks_Suppressed -- | |
6873 | ------------------------------- | |
6874 | ||
6875 | function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is | |
6876 | begin | |
9dfe12ae | 6877 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
6878 | return Is_Check_Suppressed (E, Storage_Check); | |
6879 | else | |
6880 | return Scope_Suppress (Storage_Check); | |
6881 | end if; | |
ee6ba406 | 6882 | end Storage_Checks_Suppressed; |
6883 | ||
6884 | --------------------------- | |
6885 | -- Tag_Checks_Suppressed -- | |
6886 | --------------------------- | |
6887 | ||
6888 | function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is | |
6889 | begin | |
9dfe12ae | 6890 | if Present (E) then |
6891 | if Kill_Tag_Checks (E) then | |
6892 | return True; | |
6893 | elsif Checks_May_Be_Suppressed (E) then | |
6894 | return Is_Check_Suppressed (E, Tag_Check); | |
6895 | end if; | |
6896 | end if; | |
6897 | ||
6898 | return Scope_Suppress (Tag_Check); | |
ee6ba406 | 6899 | end Tag_Checks_Suppressed; |
6900 | ||
0577b0b1 | 6901 | -------------------------- |
6902 | -- Validity_Check_Range -- | |
6903 | -------------------------- | |
6904 | ||
6905 | procedure Validity_Check_Range (N : Node_Id) is | |
6906 | begin | |
6907 | if Validity_Checks_On and Validity_Check_Operands then | |
6908 | if Nkind (N) = N_Range then | |
6909 | Ensure_Valid (Low_Bound (N)); | |
6910 | Ensure_Valid (High_Bound (N)); | |
6911 | end if; | |
6912 | end if; | |
6913 | end Validity_Check_Range; | |
6914 | ||
6915 | -------------------------------- | |
6916 | -- Validity_Checks_Suppressed -- | |
6917 | -------------------------------- | |
6918 | ||
6919 | function Validity_Checks_Suppressed (E : Entity_Id) return Boolean is | |
6920 | begin | |
6921 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
6922 | return Is_Check_Suppressed (E, Validity_Check); | |
6923 | else | |
6924 | return Scope_Suppress (Validity_Check); | |
6925 | end if; | |
6926 | end Validity_Checks_Suppressed; | |
6927 | ||
ee6ba406 | 6928 | end Checks; |