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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 | -- -- | |
38f5559f | 9 | -- Copyright (C) 1992-2005, 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- -- | |
13 | -- ware Foundation; either version 2, or (at your option) any later ver- -- | |
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 -- | |
18 | -- Public License distributed with GNAT; see file COPYING. If not, write -- | |
f27cea3a | 19 | -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- |
20 | -- Boston, MA 02110-1301, USA. -- | |
ee6ba406 | 21 | -- -- |
22 | -- GNAT was originally developed by the GNAT team at New York University. -- | |
e78e8c8e | 23 | -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
ee6ba406 | 24 | -- -- |
25 | ------------------------------------------------------------------------------ | |
26 | ||
27 | with Atree; use Atree; | |
28 | with Debug; use Debug; | |
29 | with Einfo; use Einfo; | |
30 | with Errout; use Errout; | |
31 | with Exp_Ch2; use Exp_Ch2; | |
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 | ||
13dbf220 | 221 | type Check_Type is (Access_Check, Division_Check); |
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. | |
271 | -- To be cleaned up??? | |
272 | ||
273 | function Guard_Access | |
274 | (Cond : Node_Id; | |
275 | Loc : Source_Ptr; | |
314a23b6 | 276 | Ck_Node : Node_Id) return Node_Id; |
ee6ba406 | 277 | -- In the access type case, guard the test with a test to ensure |
278 | -- that the access value is non-null, since the checks do not | |
279 | -- not apply to null access values. | |
280 | ||
281 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr); | |
282 | -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the | |
283 | -- Constraint_Error node. | |
284 | ||
285 | function Selected_Length_Checks | |
286 | (Ck_Node : Node_Id; | |
287 | Target_Typ : Entity_Id; | |
288 | Source_Typ : Entity_Id; | |
314a23b6 | 289 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 290 | -- Like Apply_Selected_Length_Checks, except it doesn't modify |
291 | -- anything, just returns a list of nodes as described in the spec of | |
292 | -- this package for the Range_Check function. | |
293 | ||
294 | function Selected_Range_Checks | |
295 | (Ck_Node : Node_Id; | |
296 | Target_Typ : Entity_Id; | |
297 | Source_Typ : Entity_Id; | |
314a23b6 | 298 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 299 | -- Like Apply_Selected_Range_Checks, except it doesn't modify anything, |
300 | -- just returns a list of nodes as described in the spec of this package | |
301 | -- for the Range_Check function. | |
302 | ||
303 | ------------------------------ | |
304 | -- Access_Checks_Suppressed -- | |
305 | ------------------------------ | |
306 | ||
307 | function Access_Checks_Suppressed (E : Entity_Id) return Boolean is | |
308 | begin | |
9dfe12ae | 309 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
310 | return Is_Check_Suppressed (E, Access_Check); | |
311 | else | |
312 | return Scope_Suppress (Access_Check); | |
313 | end if; | |
ee6ba406 | 314 | end Access_Checks_Suppressed; |
315 | ||
316 | ------------------------------------- | |
317 | -- Accessibility_Checks_Suppressed -- | |
318 | ------------------------------------- | |
319 | ||
320 | function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is | |
321 | begin | |
9dfe12ae | 322 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
323 | return Is_Check_Suppressed (E, Accessibility_Check); | |
324 | else | |
325 | return Scope_Suppress (Accessibility_Check); | |
326 | end if; | |
ee6ba406 | 327 | end Accessibility_Checks_Suppressed; |
328 | ||
329 | ------------------------- | |
330 | -- Append_Range_Checks -- | |
331 | ------------------------- | |
332 | ||
333 | procedure Append_Range_Checks | |
334 | (Checks : Check_Result; | |
335 | Stmts : List_Id; | |
336 | Suppress_Typ : Entity_Id; | |
337 | Static_Sloc : Source_Ptr; | |
338 | Flag_Node : Node_Id) | |
339 | is | |
9dfe12ae | 340 | Internal_Flag_Node : constant Node_Id := Flag_Node; |
341 | Internal_Static_Sloc : constant Source_Ptr := Static_Sloc; | |
342 | ||
ee6ba406 | 343 | Checks_On : constant Boolean := |
344 | (not Index_Checks_Suppressed (Suppress_Typ)) | |
345 | or else | |
346 | (not Range_Checks_Suppressed (Suppress_Typ)); | |
347 | ||
348 | begin | |
349 | -- For now we just return if Checks_On is false, however this should | |
350 | -- be enhanced to check for an always True value in the condition | |
351 | -- and to generate a compilation warning??? | |
352 | ||
353 | if not Checks_On then | |
354 | return; | |
355 | end if; | |
356 | ||
357 | for J in 1 .. 2 loop | |
358 | exit when No (Checks (J)); | |
359 | ||
360 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
361 | and then Present (Condition (Checks (J))) | |
362 | then | |
363 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
364 | Append_To (Stmts, Checks (J)); | |
365 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
366 | end if; | |
367 | ||
368 | else | |
369 | Append_To | |
f15731c4 | 370 | (Stmts, |
371 | Make_Raise_Constraint_Error (Internal_Static_Sloc, | |
372 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 373 | end if; |
374 | end loop; | |
375 | end Append_Range_Checks; | |
376 | ||
377 | ------------------------ | |
378 | -- Apply_Access_Check -- | |
379 | ------------------------ | |
380 | ||
381 | procedure Apply_Access_Check (N : Node_Id) is | |
382 | P : constant Node_Id := Prefix (N); | |
383 | ||
384 | begin | |
385 | if Inside_A_Generic then | |
386 | return; | |
387 | end if; | |
388 | ||
389 | if Is_Entity_Name (P) then | |
390 | Check_Unset_Reference (P); | |
391 | end if; | |
392 | ||
284faf8b | 393 | -- We do not need access checks if prefix is known to be non-null |
9dfe12ae | 394 | |
395 | if Known_Non_Null (P) then | |
ee6ba406 | 396 | return; |
397 | ||
284faf8b | 398 | -- We do not need access checks if they are suppressed on the type |
9dfe12ae | 399 | |
ee6ba406 | 400 | elsif Access_Checks_Suppressed (Etype (P)) then |
401 | return; | |
284faf8b | 402 | |
13dbf220 | 403 | -- We do not need checks if we are not generating code (i.e. the |
404 | -- expander is not active). This is not just an optimization, there | |
405 | -- are cases (e.g. with pragma Debug) where generating the checks | |
406 | -- can cause real trouble). | |
284faf8b | 407 | |
408 | elsif not Expander_Active then | |
409 | return; | |
13dbf220 | 410 | |
411 | -- We do not need checks if not needed because of short circuiting | |
412 | ||
413 | elsif not Check_Needed (P, Access_Check) then | |
414 | return; | |
9dfe12ae | 415 | end if; |
ee6ba406 | 416 | |
9dfe12ae | 417 | -- Case where P is an entity name |
418 | ||
419 | if Is_Entity_Name (P) then | |
420 | declare | |
421 | Ent : constant Entity_Id := Entity (P); | |
422 | ||
423 | begin | |
424 | if Access_Checks_Suppressed (Ent) then | |
425 | return; | |
426 | end if; | |
427 | ||
428 | -- Otherwise we are going to generate an access check, and | |
429 | -- are we have done it, the entity will now be known non null | |
430 | -- But we have to check for safe sequential semantics here! | |
431 | ||
432 | if Safe_To_Capture_Value (N, Ent) then | |
433 | Set_Is_Known_Non_Null (Ent); | |
434 | end if; | |
435 | end; | |
ee6ba406 | 436 | end if; |
9dfe12ae | 437 | |
438 | -- Access check is required | |
439 | ||
fa7497e8 | 440 | Install_Null_Excluding_Check (P); |
ee6ba406 | 441 | end Apply_Access_Check; |
442 | ||
443 | ------------------------------- | |
444 | -- Apply_Accessibility_Check -- | |
445 | ------------------------------- | |
446 | ||
447 | procedure Apply_Accessibility_Check (N : Node_Id; Typ : Entity_Id) is | |
448 | Loc : constant Source_Ptr := Sloc (N); | |
449 | Param_Ent : constant Entity_Id := Param_Entity (N); | |
450 | Param_Level : Node_Id; | |
451 | Type_Level : Node_Id; | |
452 | ||
453 | begin | |
454 | if Inside_A_Generic then | |
455 | return; | |
456 | ||
457 | -- Only apply the run-time check if the access parameter | |
458 | -- has an associated extra access level parameter and | |
459 | -- when the level of the type is less deep than the level | |
460 | -- of the access parameter. | |
461 | ||
462 | elsif Present (Param_Ent) | |
463 | and then Present (Extra_Accessibility (Param_Ent)) | |
464 | and then UI_Gt (Object_Access_Level (N), | |
465 | Type_Access_Level (Typ)) | |
466 | and then not Accessibility_Checks_Suppressed (Param_Ent) | |
467 | and then not Accessibility_Checks_Suppressed (Typ) | |
468 | then | |
469 | Param_Level := | |
470 | New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc); | |
471 | ||
472 | Type_Level := | |
473 | Make_Integer_Literal (Loc, Type_Access_Level (Typ)); | |
474 | ||
475 | -- Raise Program_Error if the accessibility level of the | |
476 | -- the access parameter is deeper than the level of the | |
477 | -- target access type. | |
478 | ||
479 | Insert_Action (N, | |
480 | Make_Raise_Program_Error (Loc, | |
481 | Condition => | |
482 | Make_Op_Gt (Loc, | |
483 | Left_Opnd => Param_Level, | |
f15731c4 | 484 | Right_Opnd => Type_Level), |
485 | Reason => PE_Accessibility_Check_Failed)); | |
ee6ba406 | 486 | |
487 | Analyze_And_Resolve (N); | |
488 | end if; | |
489 | end Apply_Accessibility_Check; | |
490 | ||
c2b56224 | 491 | --------------------------- |
492 | -- Apply_Alignment_Check -- | |
493 | --------------------------- | |
494 | ||
495 | procedure Apply_Alignment_Check (E : Entity_Id; N : Node_Id) is | |
f2a06be9 | 496 | AC : constant Node_Id := Address_Clause (E); |
497 | Typ : constant Entity_Id := Etype (E); | |
c2b56224 | 498 | Expr : Node_Id; |
499 | Loc : Source_Ptr; | |
500 | ||
5c61a0ff | 501 | Alignment_Required : constant Boolean := Maximum_Alignment > 1; |
502 | -- Constant to show whether target requires alignment checks | |
503 | ||
c2b56224 | 504 | begin |
9dfe12ae | 505 | -- See if check needed. Note that we never need a check if the |
506 | -- maximum alignment is one, since the check will always succeed | |
507 | ||
508 | if No (AC) | |
509 | or else not Check_Address_Alignment (AC) | |
5c61a0ff | 510 | or else not Alignment_Required |
9dfe12ae | 511 | then |
c2b56224 | 512 | return; |
513 | end if; | |
514 | ||
515 | Loc := Sloc (AC); | |
516 | Expr := Expression (AC); | |
517 | ||
518 | if Nkind (Expr) = N_Unchecked_Type_Conversion then | |
519 | Expr := Expression (Expr); | |
520 | ||
521 | elsif Nkind (Expr) = N_Function_Call | |
44d43e97 | 522 | and then Is_Entity_Name (Name (Expr)) |
c2b56224 | 523 | and then Is_RTE (Entity (Name (Expr)), RE_To_Address) |
524 | then | |
525 | Expr := First (Parameter_Associations (Expr)); | |
526 | ||
527 | if Nkind (Expr) = N_Parameter_Association then | |
528 | Expr := Explicit_Actual_Parameter (Expr); | |
529 | end if; | |
530 | end if; | |
531 | ||
532 | -- Here Expr is the address value. See if we know that the | |
533 | -- value is unacceptable at compile time. | |
534 | ||
535 | if Compile_Time_Known_Value (Expr) | |
f2a06be9 | 536 | and then (Known_Alignment (E) or else Known_Alignment (Typ)) |
c2b56224 | 537 | then |
f2a06be9 | 538 | declare |
539 | AL : Uint := Alignment (Typ); | |
540 | ||
541 | begin | |
542 | -- The object alignment might be more restrictive than the | |
543 | -- type alignment. | |
544 | ||
545 | if Known_Alignment (E) then | |
546 | AL := Alignment (E); | |
547 | end if; | |
548 | ||
549 | if Expr_Value (Expr) mod AL /= 0 then | |
550 | Insert_Action (N, | |
551 | Make_Raise_Program_Error (Loc, | |
552 | Reason => PE_Misaligned_Address_Value)); | |
553 | Error_Msg_NE | |
554 | ("?specified address for& not " & | |
555 | "consistent with alignment ('R'M 13.3(27))", Expr, E); | |
556 | end if; | |
557 | end; | |
c2b56224 | 558 | |
559 | -- Here we do not know if the value is acceptable, generate | |
560 | -- code to raise PE if alignment is inappropriate. | |
561 | ||
562 | else | |
563 | -- Skip generation of this code if we don't want elab code | |
564 | ||
1e16c51c | 565 | if not Restriction_Active (No_Elaboration_Code) then |
c2b56224 | 566 | Insert_After_And_Analyze (N, |
567 | Make_Raise_Program_Error (Loc, | |
568 | Condition => | |
569 | Make_Op_Ne (Loc, | |
570 | Left_Opnd => | |
571 | Make_Op_Mod (Loc, | |
572 | Left_Opnd => | |
573 | Unchecked_Convert_To | |
574 | (RTE (RE_Integer_Address), | |
9dfe12ae | 575 | Duplicate_Subexpr_No_Checks (Expr)), |
c2b56224 | 576 | Right_Opnd => |
577 | Make_Attribute_Reference (Loc, | |
578 | Prefix => New_Occurrence_Of (E, Loc), | |
579 | Attribute_Name => Name_Alignment)), | |
f15731c4 | 580 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), |
581 | Reason => PE_Misaligned_Address_Value), | |
c2b56224 | 582 | Suppress => All_Checks); |
583 | end if; | |
584 | end if; | |
585 | ||
586 | return; | |
9dfe12ae | 587 | |
588 | exception | |
589 | when RE_Not_Available => | |
590 | return; | |
c2b56224 | 591 | end Apply_Alignment_Check; |
592 | ||
ee6ba406 | 593 | ------------------------------------- |
594 | -- Apply_Arithmetic_Overflow_Check -- | |
595 | ------------------------------------- | |
596 | ||
597 | -- This routine is called only if the type is an integer type, and | |
598 | -- a software arithmetic overflow check must be performed for op | |
599 | -- (add, subtract, multiply). The check is performed only if | |
600 | -- Software_Overflow_Checking is enabled and Do_Overflow_Check | |
601 | -- is set. In this case we expand the operation into a more complex | |
602 | -- sequence of tests that ensures that overflow is properly caught. | |
603 | ||
604 | procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is | |
605 | Loc : constant Source_Ptr := Sloc (N); | |
606 | Typ : constant Entity_Id := Etype (N); | |
607 | Rtyp : constant Entity_Id := Root_Type (Typ); | |
608 | Siz : constant Int := UI_To_Int (Esize (Rtyp)); | |
609 | Dsiz : constant Int := Siz * 2; | |
610 | Opnod : Node_Id; | |
611 | Ctyp : Entity_Id; | |
612 | Opnd : Node_Id; | |
613 | Cent : RE_Id; | |
ee6ba406 | 614 | |
615 | begin | |
9dfe12ae | 616 | -- Skip this if overflow checks are done in back end, or the overflow |
617 | -- flag is not set anyway, or we are not doing code expansion. | |
618 | ||
f15731c4 | 619 | if Backend_Overflow_Checks_On_Target |
284faf8b | 620 | or else not Do_Overflow_Check (N) |
621 | or else not Expander_Active | |
ee6ba406 | 622 | then |
623 | return; | |
624 | end if; | |
625 | ||
9dfe12ae | 626 | -- Otherwise, we generate the full general code for front end overflow |
627 | -- detection, which works by doing arithmetic in a larger type: | |
ee6ba406 | 628 | |
629 | -- x op y | |
630 | ||
631 | -- is expanded into | |
632 | ||
633 | -- Typ (Checktyp (x) op Checktyp (y)); | |
634 | ||
635 | -- where Typ is the type of the original expression, and Checktyp is | |
636 | -- an integer type of sufficient length to hold the largest possible | |
637 | -- result. | |
638 | ||
639 | -- In the case where check type exceeds the size of Long_Long_Integer, | |
640 | -- we use a different approach, expanding to: | |
641 | ||
642 | -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y))) | |
643 | ||
644 | -- where xxx is Add, Multiply or Subtract as appropriate | |
645 | ||
646 | -- Find check type if one exists | |
647 | ||
648 | if Dsiz <= Standard_Integer_Size then | |
649 | Ctyp := Standard_Integer; | |
650 | ||
651 | elsif Dsiz <= Standard_Long_Long_Integer_Size then | |
652 | Ctyp := Standard_Long_Long_Integer; | |
653 | ||
654 | -- No check type exists, use runtime call | |
655 | ||
656 | else | |
657 | if Nkind (N) = N_Op_Add then | |
658 | Cent := RE_Add_With_Ovflo_Check; | |
659 | ||
660 | elsif Nkind (N) = N_Op_Multiply then | |
661 | Cent := RE_Multiply_With_Ovflo_Check; | |
662 | ||
663 | else | |
664 | pragma Assert (Nkind (N) = N_Op_Subtract); | |
665 | Cent := RE_Subtract_With_Ovflo_Check; | |
666 | end if; | |
667 | ||
668 | Rewrite (N, | |
669 | OK_Convert_To (Typ, | |
670 | Make_Function_Call (Loc, | |
671 | Name => New_Reference_To (RTE (Cent), Loc), | |
672 | Parameter_Associations => New_List ( | |
673 | OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)), | |
674 | OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N)))))); | |
675 | ||
676 | Analyze_And_Resolve (N, Typ); | |
677 | return; | |
678 | end if; | |
679 | ||
680 | -- If we fall through, we have the case where we do the arithmetic in | |
681 | -- the next higher type and get the check by conversion. In these cases | |
682 | -- Ctyp is set to the type to be used as the check type. | |
683 | ||
684 | Opnod := Relocate_Node (N); | |
685 | ||
686 | Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod)); | |
687 | ||
688 | Analyze (Opnd); | |
689 | Set_Etype (Opnd, Ctyp); | |
690 | Set_Analyzed (Opnd, True); | |
691 | Set_Left_Opnd (Opnod, Opnd); | |
692 | ||
693 | Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod)); | |
694 | ||
695 | Analyze (Opnd); | |
696 | Set_Etype (Opnd, Ctyp); | |
697 | Set_Analyzed (Opnd, True); | |
698 | Set_Right_Opnd (Opnod, Opnd); | |
699 | ||
700 | -- The type of the operation changes to the base type of the check | |
701 | -- type, and we reset the overflow check indication, since clearly | |
702 | -- no overflow is possible now that we are using a double length | |
703 | -- type. We also set the Analyzed flag to avoid a recursive attempt | |
704 | -- to expand the node. | |
705 | ||
706 | Set_Etype (Opnod, Base_Type (Ctyp)); | |
707 | Set_Do_Overflow_Check (Opnod, False); | |
708 | Set_Analyzed (Opnod, True); | |
709 | ||
710 | -- Now build the outer conversion | |
711 | ||
712 | Opnd := OK_Convert_To (Typ, Opnod); | |
ee6ba406 | 713 | Analyze (Opnd); |
714 | Set_Etype (Opnd, Typ); | |
ee6ba406 | 715 | |
9dfe12ae | 716 | -- In the discrete type case, we directly generate the range check |
717 | -- for the outer operand. This range check will implement the required | |
718 | -- overflow check. | |
719 | ||
720 | if Is_Discrete_Type (Typ) then | |
721 | Rewrite (N, Opnd); | |
722 | Generate_Range_Check (Expression (N), Typ, CE_Overflow_Check_Failed); | |
723 | ||
724 | -- For other types, we enable overflow checking on the conversion, | |
725 | -- after setting the node as analyzed to prevent recursive attempts | |
726 | -- to expand the conversion node. | |
727 | ||
728 | else | |
729 | Set_Analyzed (Opnd, True); | |
730 | Enable_Overflow_Check (Opnd); | |
731 | Rewrite (N, Opnd); | |
732 | end if; | |
733 | ||
734 | exception | |
735 | when RE_Not_Available => | |
736 | return; | |
ee6ba406 | 737 | end Apply_Arithmetic_Overflow_Check; |
738 | ||
739 | ---------------------------- | |
740 | -- Apply_Array_Size_Check -- | |
741 | ---------------------------- | |
742 | ||
80d4fec4 | 743 | -- The situation is as follows. In GNAT 3 (GCC 2.x), the size in bits |
744 | -- is computed in 32 bits without an overflow check. That's a real | |
745 | -- problem for Ada. So what we do in GNAT 3 is to approximate the | |
746 | -- size of an array by manually multiplying the element size by the | |
747 | -- number of elements, and comparing that against the allowed limits. | |
748 | ||
749 | -- In GNAT 5, the size in byte is still computed in 32 bits without | |
750 | -- an overflow check in the dynamic case, but the size in bits is | |
9651fa4e | 751 | -- computed in 64 bits. We assume that's good enough, and we do not |
752 | -- bother to generate any front end test. | |
80d4fec4 | 753 | |
ee6ba406 | 754 | procedure Apply_Array_Size_Check (N : Node_Id; Typ : Entity_Id) is |
755 | Loc : constant Source_Ptr := Sloc (N); | |
756 | Ctyp : constant Entity_Id := Component_Type (Typ); | |
757 | Ent : constant Entity_Id := Defining_Identifier (N); | |
758 | Decl : Node_Id; | |
759 | Lo : Node_Id; | |
760 | Hi : Node_Id; | |
761 | Lob : Uint; | |
762 | Hib : Uint; | |
763 | Siz : Uint; | |
764 | Xtyp : Entity_Id; | |
765 | Indx : Node_Id; | |
766 | Sizx : Node_Id; | |
767 | Code : Node_Id; | |
768 | ||
769 | Static : Boolean := True; | |
770 | -- Set false if any index subtye bound is non-static | |
771 | ||
772 | Umark : constant Uintp.Save_Mark := Uintp.Mark; | |
773 | -- We can throw away all the Uint computations here, since they are | |
774 | -- done only to generate boolean test results. | |
775 | ||
776 | Check_Siz : Uint; | |
777 | -- Size to check against | |
778 | ||
779 | function Is_Address_Or_Import (Decl : Node_Id) return Boolean; | |
780 | -- Determines if Decl is an address clause or Import/Interface pragma | |
781 | -- that references the defining identifier of the current declaration. | |
782 | ||
783 | -------------------------- | |
784 | -- Is_Address_Or_Import -- | |
785 | -------------------------- | |
786 | ||
787 | function Is_Address_Or_Import (Decl : Node_Id) return Boolean is | |
788 | begin | |
789 | if Nkind (Decl) = N_At_Clause then | |
790 | return Chars (Identifier (Decl)) = Chars (Ent); | |
791 | ||
792 | elsif Nkind (Decl) = N_Attribute_Definition_Clause then | |
793 | return | |
794 | Chars (Decl) = Name_Address | |
795 | and then | |
796 | Nkind (Name (Decl)) = N_Identifier | |
797 | and then | |
798 | Chars (Name (Decl)) = Chars (Ent); | |
799 | ||
800 | elsif Nkind (Decl) = N_Pragma then | |
801 | if (Chars (Decl) = Name_Import | |
802 | or else | |
803 | Chars (Decl) = Name_Interface) | |
804 | and then Present (Pragma_Argument_Associations (Decl)) | |
805 | then | |
806 | declare | |
807 | F : constant Node_Id := | |
808 | First (Pragma_Argument_Associations (Decl)); | |
809 | ||
810 | begin | |
811 | return | |
812 | Present (F) | |
813 | and then | |
814 | Present (Next (F)) | |
815 | and then | |
816 | Nkind (Expression (Next (F))) = N_Identifier | |
817 | and then | |
818 | Chars (Expression (Next (F))) = Chars (Ent); | |
819 | end; | |
820 | ||
821 | else | |
822 | return False; | |
823 | end if; | |
824 | ||
825 | else | |
826 | return False; | |
827 | end if; | |
828 | end Is_Address_Or_Import; | |
829 | ||
830 | -- Start of processing for Apply_Array_Size_Check | |
831 | ||
832 | begin | |
9651fa4e | 833 | -- Do size check on local arrays. We only need this in the GCC 2 |
834 | -- case, since in GCC 3, we expect the back end to properly handle | |
835 | -- things. This routine can be removed when we baseline GNAT 3. | |
836 | ||
837 | if Opt.GCC_Version >= 3 then | |
838 | return; | |
839 | end if; | |
840 | ||
80d4fec4 | 841 | -- No need for a check if not expanding |
842 | ||
843 | if not Expander_Active then | |
ee6ba406 | 844 | return; |
845 | end if; | |
846 | ||
80d4fec4 | 847 | -- No need for a check if checks are suppressed |
848 | ||
849 | if Storage_Checks_Suppressed (Typ) then | |
850 | return; | |
851 | end if; | |
852 | ||
853 | -- It is pointless to insert this check inside an init proc, because | |
ee6ba406 | 854 | -- that's too late, we have already built the object to be the right |
855 | -- size, and if it's too large, too bad! | |
856 | ||
857 | if Inside_Init_Proc then | |
858 | return; | |
859 | end if; | |
860 | ||
861 | -- Look head for pragma interface/import or address clause applying | |
862 | -- to this entity. If found, we suppress the check entirely. For now | |
863 | -- we only look ahead 20 declarations to stop this becoming too slow | |
864 | -- Note that eventually this whole routine gets moved to gigi. | |
865 | ||
866 | Decl := N; | |
867 | for Ctr in 1 .. 20 loop | |
868 | Next (Decl); | |
869 | exit when No (Decl); | |
870 | ||
871 | if Is_Address_Or_Import (Decl) then | |
872 | return; | |
873 | end if; | |
874 | end loop; | |
875 | ||
9651fa4e | 876 | -- First step is to calculate the maximum number of elements. For |
877 | -- this calculation, we use the actual size of the subtype if it is | |
878 | -- static, and if a bound of a subtype is non-static, we go to the | |
879 | -- bound of the base type. | |
ee6ba406 | 880 | |
9651fa4e | 881 | Siz := Uint_1; |
882 | Indx := First_Index (Typ); | |
883 | while Present (Indx) loop | |
884 | Xtyp := Etype (Indx); | |
885 | Lo := Type_Low_Bound (Xtyp); | |
886 | Hi := Type_High_Bound (Xtyp); | |
ee6ba406 | 887 | |
9651fa4e | 888 | -- If any bound raises constraint error, we will never get this |
889 | -- far, so there is no need to generate any kind of check. | |
ee6ba406 | 890 | |
9651fa4e | 891 | if Raises_Constraint_Error (Lo) |
892 | or else | |
893 | Raises_Constraint_Error (Hi) | |
894 | then | |
895 | Uintp.Release (Umark); | |
ee6ba406 | 896 | return; |
897 | end if; | |
ee6ba406 | 898 | |
9651fa4e | 899 | -- Otherwise get bounds values |
ee6ba406 | 900 | |
9651fa4e | 901 | if Is_Static_Expression (Lo) then |
902 | Lob := Expr_Value (Lo); | |
903 | else | |
904 | Lob := Expr_Value (Type_Low_Bound (Base_Type (Xtyp))); | |
905 | Static := False; | |
906 | end if; | |
ee6ba406 | 907 | |
9651fa4e | 908 | if Is_Static_Expression (Hi) then |
909 | Hib := Expr_Value (Hi); | |
910 | else | |
911 | Hib := Expr_Value (Type_High_Bound (Base_Type (Xtyp))); | |
912 | Static := False; | |
913 | end if; | |
ee6ba406 | 914 | |
9651fa4e | 915 | Siz := Siz * UI_Max (Hib - Lob + 1, Uint_0); |
916 | Next_Index (Indx); | |
917 | end loop; | |
ee6ba406 | 918 | |
9651fa4e | 919 | -- Compute the limit against which we want to check. For subprograms, |
920 | -- where the array will go on the stack, we use 8*2**24, which (in | |
921 | -- bits) is the size of a 16 megabyte array. | |
ee6ba406 | 922 | |
9651fa4e | 923 | if Is_Subprogram (Scope (Ent)) then |
924 | Check_Siz := Uint_2 ** 27; | |
925 | else | |
926 | Check_Siz := Uint_2 ** 31; | |
927 | end if; | |
ee6ba406 | 928 | |
9651fa4e | 929 | -- If we have all static bounds and Siz is too large, then we know |
930 | -- we know we have a storage error right now, so generate message | |
ee6ba406 | 931 | |
9651fa4e | 932 | if Static and then Siz >= Check_Siz then |
933 | Insert_Action (N, | |
934 | Make_Raise_Storage_Error (Loc, | |
935 | Reason => SE_Object_Too_Large)); | |
936 | Error_Msg_N ("?Storage_Error will be raised at run-time", N); | |
937 | Uintp.Release (Umark); | |
938 | return; | |
939 | end if; | |
ee6ba406 | 940 | |
9651fa4e | 941 | -- Case of component size known at compile time. If the array |
942 | -- size is definitely in range, then we do not need a check. | |
ee6ba406 | 943 | |
9651fa4e | 944 | if Known_Esize (Ctyp) |
945 | and then Siz * Esize (Ctyp) < Check_Siz | |
946 | then | |
947 | Uintp.Release (Umark); | |
948 | return; | |
949 | end if; | |
ee6ba406 | 950 | |
9651fa4e | 951 | -- Here if a dynamic check is required |
ee6ba406 | 952 | |
9651fa4e | 953 | -- What we do is to build an expression for the size of the array, |
954 | -- which is computed as the 'Size of the array component, times | |
955 | -- the size of each dimension. | |
ee6ba406 | 956 | |
9651fa4e | 957 | Uintp.Release (Umark); |
80d4fec4 | 958 | |
9651fa4e | 959 | Sizx := |
960 | Make_Attribute_Reference (Loc, | |
961 | Prefix => New_Occurrence_Of (Ctyp, Loc), | |
962 | Attribute_Name => Name_Size); | |
80d4fec4 | 963 | |
9651fa4e | 964 | Indx := First_Index (Typ); |
965 | for J in 1 .. Number_Dimensions (Typ) loop | |
966 | if Sloc (Etype (Indx)) = Sloc (N) then | |
967 | Ensure_Defined (Etype (Indx), N); | |
968 | end if; | |
80d4fec4 | 969 | |
ee6ba406 | 970 | Sizx := |
9651fa4e | 971 | Make_Op_Multiply (Loc, |
972 | Left_Opnd => Sizx, | |
973 | Right_Opnd => | |
974 | Make_Attribute_Reference (Loc, | |
975 | Prefix => New_Occurrence_Of (Typ, Loc), | |
976 | Attribute_Name => Name_Length, | |
977 | Expressions => New_List ( | |
978 | Make_Integer_Literal (Loc, J)))); | |
979 | Next_Index (Indx); | |
980 | end loop; | |
80d4fec4 | 981 | |
9651fa4e | 982 | -- Emit the check |
ee6ba406 | 983 | |
984 | Code := | |
985 | Make_Raise_Storage_Error (Loc, | |
986 | Condition => | |
987 | Make_Op_Ge (Loc, | |
988 | Left_Opnd => Sizx, | |
989 | Right_Opnd => | |
80d4fec4 | 990 | Make_Integer_Literal (Loc, |
991 | Intval => Check_Siz)), | |
9651fa4e | 992 | Reason => SE_Object_Too_Large); |
ee6ba406 | 993 | |
994 | Set_Size_Check_Code (Defining_Identifier (N), Code); | |
80d4fec4 | 995 | Insert_Action (N, Code, Suppress => All_Checks); |
ee6ba406 | 996 | end Apply_Array_Size_Check; |
997 | ||
998 | ---------------------------- | |
999 | -- Apply_Constraint_Check -- | |
1000 | ---------------------------- | |
1001 | ||
1002 | procedure Apply_Constraint_Check | |
1003 | (N : Node_Id; | |
1004 | Typ : Entity_Id; | |
1005 | No_Sliding : Boolean := False) | |
1006 | is | |
1007 | Desig_Typ : Entity_Id; | |
1008 | ||
1009 | begin | |
1010 | if Inside_A_Generic then | |
1011 | return; | |
1012 | ||
1013 | elsif Is_Scalar_Type (Typ) then | |
1014 | Apply_Scalar_Range_Check (N, Typ); | |
1015 | ||
1016 | elsif Is_Array_Type (Typ) then | |
1017 | ||
05fcfafb | 1018 | -- A useful optimization: an aggregate with only an others clause |
5f260d20 | 1019 | -- always has the right bounds. |
1020 | ||
1021 | if Nkind (N) = N_Aggregate | |
1022 | and then No (Expressions (N)) | |
1023 | and then Nkind | |
1024 | (First (Choices (First (Component_Associations (N))))) | |
1025 | = N_Others_Choice | |
1026 | then | |
1027 | return; | |
1028 | end if; | |
1029 | ||
ee6ba406 | 1030 | if Is_Constrained (Typ) then |
1031 | Apply_Length_Check (N, Typ); | |
1032 | ||
1033 | if No_Sliding then | |
1034 | Apply_Range_Check (N, Typ); | |
1035 | end if; | |
1036 | else | |
1037 | Apply_Range_Check (N, Typ); | |
1038 | end if; | |
1039 | ||
1040 | elsif (Is_Record_Type (Typ) | |
1041 | or else Is_Private_Type (Typ)) | |
1042 | and then Has_Discriminants (Base_Type (Typ)) | |
1043 | and then Is_Constrained (Typ) | |
1044 | then | |
1045 | Apply_Discriminant_Check (N, Typ); | |
1046 | ||
1047 | elsif Is_Access_Type (Typ) then | |
1048 | ||
1049 | Desig_Typ := Designated_Type (Typ); | |
1050 | ||
1051 | -- No checks necessary if expression statically null | |
1052 | ||
1053 | if Nkind (N) = N_Null then | |
1054 | null; | |
1055 | ||
1056 | -- No sliding possible on access to arrays | |
1057 | ||
1058 | elsif Is_Array_Type (Desig_Typ) then | |
1059 | if Is_Constrained (Desig_Typ) then | |
1060 | Apply_Length_Check (N, Typ); | |
1061 | end if; | |
1062 | ||
1063 | Apply_Range_Check (N, Typ); | |
1064 | ||
1065 | elsif Has_Discriminants (Base_Type (Desig_Typ)) | |
1066 | and then Is_Constrained (Desig_Typ) | |
1067 | then | |
1068 | Apply_Discriminant_Check (N, Typ); | |
1069 | end if; | |
fa7497e8 | 1070 | |
1071 | if Can_Never_Be_Null (Typ) | |
1072 | and then not Can_Never_Be_Null (Etype (N)) | |
1073 | then | |
1074 | Install_Null_Excluding_Check (N); | |
1075 | end if; | |
ee6ba406 | 1076 | end if; |
1077 | end Apply_Constraint_Check; | |
1078 | ||
1079 | ------------------------------ | |
1080 | -- Apply_Discriminant_Check -- | |
1081 | ------------------------------ | |
1082 | ||
1083 | procedure Apply_Discriminant_Check | |
1084 | (N : Node_Id; | |
1085 | Typ : Entity_Id; | |
1086 | Lhs : Node_Id := Empty) | |
1087 | is | |
1088 | Loc : constant Source_Ptr := Sloc (N); | |
1089 | Do_Access : constant Boolean := Is_Access_Type (Typ); | |
1090 | S_Typ : Entity_Id := Etype (N); | |
1091 | Cond : Node_Id; | |
1092 | T_Typ : Entity_Id; | |
1093 | ||
1094 | function Is_Aliased_Unconstrained_Component return Boolean; | |
1095 | -- It is possible for an aliased component to have a nominal | |
1096 | -- unconstrained subtype (through instantiation). If this is a | |
1097 | -- discriminated component assigned in the expansion of an aggregate | |
1098 | -- in an initialization, the check must be suppressed. This unusual | |
1099 | -- situation requires a predicate of its own (see 7503-008). | |
1100 | ||
1101 | ---------------------------------------- | |
1102 | -- Is_Aliased_Unconstrained_Component -- | |
1103 | ---------------------------------------- | |
1104 | ||
1105 | function Is_Aliased_Unconstrained_Component return Boolean is | |
1106 | Comp : Entity_Id; | |
1107 | Pref : Node_Id; | |
1108 | ||
1109 | begin | |
1110 | if Nkind (Lhs) /= N_Selected_Component then | |
1111 | return False; | |
1112 | else | |
1113 | Comp := Entity (Selector_Name (Lhs)); | |
1114 | Pref := Prefix (Lhs); | |
1115 | end if; | |
1116 | ||
1117 | if Ekind (Comp) /= E_Component | |
1118 | or else not Is_Aliased (Comp) | |
1119 | then | |
1120 | return False; | |
1121 | end if; | |
1122 | ||
1123 | return not Comes_From_Source (Pref) | |
1124 | and then In_Instance | |
1125 | and then not Is_Constrained (Etype (Comp)); | |
1126 | end Is_Aliased_Unconstrained_Component; | |
1127 | ||
1128 | -- Start of processing for Apply_Discriminant_Check | |
1129 | ||
1130 | begin | |
1131 | if Do_Access then | |
1132 | T_Typ := Designated_Type (Typ); | |
1133 | else | |
1134 | T_Typ := Typ; | |
1135 | end if; | |
1136 | ||
1137 | -- Nothing to do if discriminant checks are suppressed or else no code | |
1138 | -- is to be generated | |
1139 | ||
1140 | if not Expander_Active | |
1141 | or else Discriminant_Checks_Suppressed (T_Typ) | |
1142 | then | |
1143 | return; | |
1144 | end if; | |
1145 | ||
05fcfafb | 1146 | -- No discriminant checks necessary for an access when expression |
ee6ba406 | 1147 | -- is statically Null. This is not only an optimization, this is |
1148 | -- fundamental because otherwise discriminant checks may be generated | |
05fcfafb | 1149 | -- in init procs for types containing an access to a not-yet-frozen |
ee6ba406 | 1150 | -- record, causing a deadly forward reference. |
1151 | ||
1152 | -- Also, if the expression is of an access type whose designated | |
1153 | -- type is incomplete, then the access value must be null and | |
1154 | -- we suppress the check. | |
1155 | ||
1156 | if Nkind (N) = N_Null then | |
1157 | return; | |
1158 | ||
1159 | elsif Is_Access_Type (S_Typ) then | |
1160 | S_Typ := Designated_Type (S_Typ); | |
1161 | ||
1162 | if Ekind (S_Typ) = E_Incomplete_Type then | |
1163 | return; | |
1164 | end if; | |
1165 | end if; | |
1166 | ||
1167 | -- If an assignment target is present, then we need to generate | |
1168 | -- the actual subtype if the target is a parameter or aliased | |
1169 | -- object with an unconstrained nominal subtype. | |
1170 | ||
1171 | if Present (Lhs) | |
1172 | and then (Present (Param_Entity (Lhs)) | |
1173 | or else (not Is_Constrained (T_Typ) | |
1174 | and then Is_Aliased_View (Lhs) | |
1175 | and then not Is_Aliased_Unconstrained_Component)) | |
1176 | then | |
1177 | T_Typ := Get_Actual_Subtype (Lhs); | |
1178 | end if; | |
1179 | ||
1180 | -- Nothing to do if the type is unconstrained (this is the case | |
1181 | -- where the actual subtype in the RM sense of N is unconstrained | |
1182 | -- and no check is required). | |
1183 | ||
1184 | if not Is_Constrained (T_Typ) then | |
1185 | return; | |
05fcfafb | 1186 | |
1187 | -- Ada 2005: nothing to do if the type is one for which there is a | |
1188 | -- partial view that is constrained. | |
1189 | ||
1190 | elsif Ada_Version >= Ada_05 | |
1191 | and then Has_Constrained_Partial_View (Base_Type (T_Typ)) | |
1192 | then | |
1193 | return; | |
ee6ba406 | 1194 | end if; |
1195 | ||
00f91aef | 1196 | -- Nothing to do if the type is an Unchecked_Union |
1197 | ||
1198 | if Is_Unchecked_Union (Base_Type (T_Typ)) then | |
1199 | return; | |
1200 | end if; | |
1201 | ||
ee6ba406 | 1202 | -- Suppress checks if the subtypes are the same. |
1203 | -- the check must be preserved in an assignment to a formal, because | |
1204 | -- the constraint is given by the actual. | |
1205 | ||
1206 | if Nkind (Original_Node (N)) /= N_Allocator | |
1207 | and then (No (Lhs) | |
1208 | or else not Is_Entity_Name (Lhs) | |
9dfe12ae | 1209 | or else No (Param_Entity (Lhs))) |
ee6ba406 | 1210 | then |
1211 | if (Etype (N) = Typ | |
1212 | or else (Do_Access and then Designated_Type (Typ) = S_Typ)) | |
1213 | and then not Is_Aliased_View (Lhs) | |
1214 | then | |
1215 | return; | |
1216 | end if; | |
1217 | ||
1218 | -- We can also eliminate checks on allocators with a subtype mark | |
1219 | -- that coincides with the context type. The context type may be a | |
1220 | -- subtype without a constraint (common case, a generic actual). | |
1221 | ||
1222 | elsif Nkind (Original_Node (N)) = N_Allocator | |
1223 | and then Is_Entity_Name (Expression (Original_Node (N))) | |
1224 | then | |
1225 | declare | |
9dfe12ae | 1226 | Alloc_Typ : constant Entity_Id := |
1227 | Entity (Expression (Original_Node (N))); | |
ee6ba406 | 1228 | |
1229 | begin | |
1230 | if Alloc_Typ = T_Typ | |
1231 | or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration | |
1232 | and then Is_Entity_Name ( | |
1233 | Subtype_Indication (Parent (T_Typ))) | |
1234 | and then Alloc_Typ = Base_Type (T_Typ)) | |
1235 | ||
1236 | then | |
1237 | return; | |
1238 | end if; | |
1239 | end; | |
1240 | end if; | |
1241 | ||
1242 | -- See if we have a case where the types are both constrained, and | |
1243 | -- all the constraints are constants. In this case, we can do the | |
1244 | -- check successfully at compile time. | |
1245 | ||
9dfe12ae | 1246 | -- We skip this check for the case where the node is a rewritten` |
ee6ba406 | 1247 | -- allocator, because it already carries the context subtype, and |
1248 | -- extracting the discriminants from the aggregate is messy. | |
1249 | ||
1250 | if Is_Constrained (S_Typ) | |
1251 | and then Nkind (Original_Node (N)) /= N_Allocator | |
1252 | then | |
1253 | declare | |
1254 | DconT : Elmt_Id; | |
1255 | Discr : Entity_Id; | |
1256 | DconS : Elmt_Id; | |
1257 | ItemS : Node_Id; | |
1258 | ItemT : Node_Id; | |
1259 | ||
1260 | begin | |
1261 | -- S_Typ may not have discriminants in the case where it is a | |
1262 | -- private type completed by a default discriminated type. In | |
1263 | -- that case, we need to get the constraints from the | |
1264 | -- underlying_type. If the underlying type is unconstrained (i.e. | |
1265 | -- has no default discriminants) no check is needed. | |
1266 | ||
1267 | if Has_Discriminants (S_Typ) then | |
1268 | Discr := First_Discriminant (S_Typ); | |
1269 | DconS := First_Elmt (Discriminant_Constraint (S_Typ)); | |
1270 | ||
1271 | else | |
1272 | Discr := First_Discriminant (Underlying_Type (S_Typ)); | |
1273 | DconS := | |
1274 | First_Elmt | |
1275 | (Discriminant_Constraint (Underlying_Type (S_Typ))); | |
1276 | ||
1277 | if No (DconS) then | |
1278 | return; | |
1279 | end if; | |
fccb5da7 | 1280 | |
1281 | -- A further optimization: if T_Typ is derived from S_Typ | |
1282 | -- without imposing a constraint, no check is needed. | |
1283 | ||
1284 | if Nkind (Original_Node (Parent (T_Typ))) = | |
1285 | N_Full_Type_Declaration | |
1286 | then | |
1287 | declare | |
5c61a0ff | 1288 | Type_Def : constant Node_Id := |
fccb5da7 | 1289 | Type_Definition |
1290 | (Original_Node (Parent (T_Typ))); | |
1291 | begin | |
1292 | if Nkind (Type_Def) = N_Derived_Type_Definition | |
1293 | and then Is_Entity_Name (Subtype_Indication (Type_Def)) | |
1294 | and then Entity (Subtype_Indication (Type_Def)) = S_Typ | |
1295 | then | |
1296 | return; | |
1297 | end if; | |
1298 | end; | |
1299 | end if; | |
ee6ba406 | 1300 | end if; |
1301 | ||
1302 | DconT := First_Elmt (Discriminant_Constraint (T_Typ)); | |
1303 | ||
1304 | while Present (Discr) loop | |
1305 | ItemS := Node (DconS); | |
1306 | ItemT := Node (DconT); | |
1307 | ||
1308 | exit when | |
1309 | not Is_OK_Static_Expression (ItemS) | |
1310 | or else | |
1311 | not Is_OK_Static_Expression (ItemT); | |
1312 | ||
1313 | if Expr_Value (ItemS) /= Expr_Value (ItemT) then | |
1314 | if Do_Access then -- needs run-time check. | |
1315 | exit; | |
1316 | else | |
1317 | Apply_Compile_Time_Constraint_Error | |
f15731c4 | 1318 | (N, "incorrect value for discriminant&?", |
1319 | CE_Discriminant_Check_Failed, Ent => Discr); | |
ee6ba406 | 1320 | return; |
1321 | end if; | |
1322 | end if; | |
1323 | ||
1324 | Next_Elmt (DconS); | |
1325 | Next_Elmt (DconT); | |
1326 | Next_Discriminant (Discr); | |
1327 | end loop; | |
1328 | ||
1329 | if No (Discr) then | |
1330 | return; | |
1331 | end if; | |
1332 | end; | |
1333 | end if; | |
1334 | ||
1335 | -- Here we need a discriminant check. First build the expression | |
1336 | -- for the comparisons of the discriminants: | |
1337 | ||
1338 | -- (n.disc1 /= typ.disc1) or else | |
1339 | -- (n.disc2 /= typ.disc2) or else | |
1340 | -- ... | |
1341 | -- (n.discn /= typ.discn) | |
1342 | ||
1343 | Cond := Build_Discriminant_Checks (N, T_Typ); | |
1344 | ||
1345 | -- If Lhs is set and is a parameter, then the condition is | |
1346 | -- guarded by: lhs'constrained and then (condition built above) | |
1347 | ||
1348 | if Present (Param_Entity (Lhs)) then | |
1349 | Cond := | |
1350 | Make_And_Then (Loc, | |
1351 | Left_Opnd => | |
1352 | Make_Attribute_Reference (Loc, | |
1353 | Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc), | |
1354 | Attribute_Name => Name_Constrained), | |
1355 | Right_Opnd => Cond); | |
1356 | end if; | |
1357 | ||
1358 | if Do_Access then | |
1359 | Cond := Guard_Access (Cond, Loc, N); | |
1360 | end if; | |
1361 | ||
1362 | Insert_Action (N, | |
f15731c4 | 1363 | Make_Raise_Constraint_Error (Loc, |
1364 | Condition => Cond, | |
1365 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 1366 | end Apply_Discriminant_Check; |
1367 | ||
1368 | ------------------------ | |
1369 | -- Apply_Divide_Check -- | |
1370 | ------------------------ | |
1371 | ||
1372 | procedure Apply_Divide_Check (N : Node_Id) is | |
1373 | Loc : constant Source_Ptr := Sloc (N); | |
1374 | Typ : constant Entity_Id := Etype (N); | |
1375 | Left : constant Node_Id := Left_Opnd (N); | |
1376 | Right : constant Node_Id := Right_Opnd (N); | |
1377 | ||
1378 | LLB : Uint; | |
1379 | Llo : Uint; | |
1380 | Lhi : Uint; | |
1381 | LOK : Boolean; | |
1382 | Rlo : Uint; | |
1383 | Rhi : Uint; | |
1384 | ROK : Boolean; | |
1385 | ||
1386 | begin | |
1387 | if Expander_Active | |
13dbf220 | 1388 | and then not Backend_Divide_Checks_On_Target |
1389 | and then Check_Needed (Right, Division_Check) | |
ee6ba406 | 1390 | then |
1391 | Determine_Range (Right, ROK, Rlo, Rhi); | |
1392 | ||
1393 | -- See if division by zero possible, and if so generate test. This | |
1394 | -- part of the test is not controlled by the -gnato switch. | |
1395 | ||
1396 | if Do_Division_Check (N) then | |
ee6ba406 | 1397 | if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then |
1398 | Insert_Action (N, | |
1399 | Make_Raise_Constraint_Error (Loc, | |
1400 | Condition => | |
1401 | Make_Op_Eq (Loc, | |
9dfe12ae | 1402 | Left_Opnd => Duplicate_Subexpr_Move_Checks (Right), |
f15731c4 | 1403 | Right_Opnd => Make_Integer_Literal (Loc, 0)), |
1404 | Reason => CE_Divide_By_Zero)); | |
ee6ba406 | 1405 | end if; |
1406 | end if; | |
1407 | ||
1408 | -- Test for extremely annoying case of xxx'First divided by -1 | |
1409 | ||
1410 | if Do_Overflow_Check (N) then | |
ee6ba406 | 1411 | if Nkind (N) = N_Op_Divide |
1412 | and then Is_Signed_Integer_Type (Typ) | |
1413 | then | |
1414 | Determine_Range (Left, LOK, Llo, Lhi); | |
1415 | LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ))); | |
1416 | ||
1417 | if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) | |
1418 | and then | |
1419 | ((not LOK) or else (Llo = LLB)) | |
1420 | then | |
1421 | Insert_Action (N, | |
1422 | Make_Raise_Constraint_Error (Loc, | |
1423 | Condition => | |
1424 | Make_And_Then (Loc, | |
1425 | ||
1426 | Make_Op_Eq (Loc, | |
9dfe12ae | 1427 | Left_Opnd => |
1428 | Duplicate_Subexpr_Move_Checks (Left), | |
ee6ba406 | 1429 | Right_Opnd => Make_Integer_Literal (Loc, LLB)), |
1430 | ||
1431 | Make_Op_Eq (Loc, | |
9dfe12ae | 1432 | Left_Opnd => |
1433 | Duplicate_Subexpr (Right), | |
ee6ba406 | 1434 | Right_Opnd => |
f15731c4 | 1435 | Make_Integer_Literal (Loc, -1))), |
1436 | Reason => CE_Overflow_Check_Failed)); | |
ee6ba406 | 1437 | end if; |
1438 | end if; | |
1439 | end if; | |
1440 | end if; | |
1441 | end Apply_Divide_Check; | |
1442 | ||
5329ca64 | 1443 | ---------------------------------- |
1444 | -- Apply_Float_Conversion_Check -- | |
1445 | ---------------------------------- | |
1446 | ||
1447 | -- Let F and I be the source and target types of the conversion. | |
1448 | -- The Ada standard specifies that a floating-point value X is rounded | |
1449 | -- to the nearest integer, with halfway cases being rounded away from | |
1450 | -- zero. The rounded value of X is checked against I'Range. | |
1451 | ||
1452 | -- The catch in the above paragraph is that there is no good way | |
1453 | -- to know whether the round-to-integer operation resulted in | |
1454 | -- overflow. A remedy is to perform a range check in the floating-point | |
1455 | -- domain instead, however: | |
1456 | -- (1) The bounds may not be known at compile time | |
1457 | -- (2) The check must take into account possible rounding. | |
1458 | -- (3) The range of type I may not be exactly representable in F. | |
1459 | -- (4) The end-points I'First - 0.5 and I'Last + 0.5 may or may | |
1460 | -- not be in range, depending on the sign of I'First and I'Last. | |
1461 | -- (5) X may be a NaN, which will fail any comparison | |
1462 | ||
1463 | -- The following steps take care of these issues converting X: | |
1464 | -- (1) If either I'First or I'Last is not known at compile time, use | |
1465 | -- I'Base instead of I in the next three steps and perform a | |
1466 | -- regular range check against I'Range after conversion. | |
1467 | -- (2) If I'First - 0.5 is representable in F then let Lo be that | |
1468 | -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be | |
1469 | -- F'Machine (T) and let Lo_OK be (Lo >= I'First). In other words, | |
1470 | -- take one of the closest floating-point numbers to T, and see if | |
1471 | -- it is in range or not. | |
1472 | -- (3) If I'Last + 0.5 is representable in F then let Hi be that value | |
1473 | -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be | |
1474 | -- F'Rounding (T) and let Hi_OK be (Hi <= I'Last). | |
1475 | -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo) | |
1476 | -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi) | |
1477 | ||
1478 | procedure Apply_Float_Conversion_Check | |
1479 | (Ck_Node : Node_Id; | |
1480 | Target_Typ : Entity_Id) | |
1481 | is | |
1482 | LB : constant Node_Id := Type_Low_Bound (Target_Typ); | |
1483 | HB : constant Node_Id := Type_High_Bound (Target_Typ); | |
1484 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
1485 | Expr_Type : constant Entity_Id := Base_Type (Etype (Ck_Node)); | |
1486 | Target_Base : constant Entity_Id := Implementation_Base_Type | |
1487 | (Target_Typ); | |
1488 | Max_Bound : constant Uint := UI_Expon | |
1489 | (Machine_Radix (Expr_Type), | |
1490 | Machine_Mantissa (Expr_Type) - 1) - 1; | |
1491 | -- Largest bound, so bound plus or minus half is a machine number of F | |
1492 | ||
1493 | Ifirst, | |
1494 | Ilast : Uint; -- Bounds of integer type | |
1495 | Lo, Hi : Ureal; -- Bounds to check in floating-point domain | |
1496 | Lo_OK, | |
1497 | Hi_OK : Boolean; -- True iff Lo resp. Hi belongs to I'Range | |
1498 | ||
1499 | Lo_Chk, | |
1500 | Hi_Chk : Node_Id; -- Expressions that are False iff check fails | |
1501 | ||
1502 | Reason : RT_Exception_Code; | |
1503 | ||
1504 | begin | |
1505 | if not Compile_Time_Known_Value (LB) | |
1506 | or not Compile_Time_Known_Value (HB) | |
1507 | then | |
1508 | declare | |
1509 | -- First check that the value falls in the range of the base | |
1510 | -- type, to prevent overflow during conversion and then | |
1511 | -- perform a regular range check against the (dynamic) bounds. | |
1512 | ||
1513 | Par : constant Node_Id := Parent (Ck_Node); | |
1514 | ||
1515 | pragma Assert (Target_Base /= Target_Typ); | |
1516 | pragma Assert (Nkind (Par) = N_Type_Conversion); | |
1517 | ||
1518 | Temp : constant Entity_Id := | |
1519 | Make_Defining_Identifier (Loc, | |
1520 | Chars => New_Internal_Name ('T')); | |
1521 | ||
1522 | begin | |
1523 | Apply_Float_Conversion_Check (Ck_Node, Target_Base); | |
1524 | Set_Etype (Temp, Target_Base); | |
1525 | ||
1526 | Insert_Action (Parent (Par), | |
1527 | Make_Object_Declaration (Loc, | |
1528 | Defining_Identifier => Temp, | |
1529 | Object_Definition => New_Occurrence_Of (Target_Typ, Loc), | |
1530 | Expression => New_Copy_Tree (Par)), | |
1531 | Suppress => All_Checks); | |
1532 | ||
1533 | Insert_Action (Par, | |
1534 | Make_Raise_Constraint_Error (Loc, | |
1535 | Condition => | |
1536 | Make_Not_In (Loc, | |
1537 | Left_Opnd => New_Occurrence_Of (Temp, Loc), | |
1538 | Right_Opnd => New_Occurrence_Of (Target_Typ, Loc)), | |
1539 | Reason => CE_Range_Check_Failed)); | |
1540 | Rewrite (Par, New_Occurrence_Of (Temp, Loc)); | |
1541 | ||
1542 | return; | |
1543 | end; | |
1544 | end if; | |
1545 | ||
1546 | -- Get the bounds of the target type | |
1547 | ||
1548 | Ifirst := Expr_Value (LB); | |
1549 | Ilast := Expr_Value (HB); | |
1550 | ||
1551 | -- Check against lower bound | |
1552 | ||
1553 | if abs (Ifirst) < Max_Bound then | |
1554 | Lo := UR_From_Uint (Ifirst) - Ureal_Half; | |
1555 | Lo_OK := (Ifirst > 0); | |
1556 | else | |
1557 | Lo := Machine (Expr_Type, UR_From_Uint (Ifirst), Round_Even, Ck_Node); | |
1558 | Lo_OK := (Lo >= UR_From_Uint (Ifirst)); | |
1559 | end if; | |
1560 | ||
1561 | if Lo_OK then | |
1562 | ||
1563 | -- Lo_Chk := (X >= Lo) | |
1564 | ||
1565 | Lo_Chk := Make_Op_Ge (Loc, | |
1566 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1567 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
1568 | ||
1569 | else | |
1570 | -- Lo_Chk := (X > Lo) | |
1571 | ||
1572 | Lo_Chk := Make_Op_Gt (Loc, | |
1573 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1574 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
1575 | end if; | |
1576 | ||
1577 | -- Check against higher bound | |
1578 | ||
1579 | if abs (Ilast) < Max_Bound then | |
1580 | Hi := UR_From_Uint (Ilast) + Ureal_Half; | |
1581 | Hi_OK := (Ilast < 0); | |
1582 | else | |
1583 | Hi := Machine (Expr_Type, UR_From_Uint (Ilast), Round_Even, Ck_Node); | |
1584 | Hi_OK := (Hi <= UR_From_Uint (Ilast)); | |
1585 | end if; | |
1586 | ||
1587 | if Hi_OK then | |
1588 | ||
1589 | -- Hi_Chk := (X <= Hi) | |
1590 | ||
1591 | Hi_Chk := Make_Op_Le (Loc, | |
1592 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1593 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
1594 | ||
1595 | else | |
1596 | -- Hi_Chk := (X < Hi) | |
1597 | ||
1598 | Hi_Chk := Make_Op_Lt (Loc, | |
1599 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1600 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
1601 | end if; | |
1602 | ||
1603 | -- If the bounds of the target type are the same as those of the | |
1604 | -- base type, the check is an overflow check as a range check is | |
1605 | -- not performed in these cases. | |
1606 | ||
1607 | if Expr_Value (Type_Low_Bound (Target_Base)) = Ifirst | |
1608 | and then Expr_Value (Type_High_Bound (Target_Base)) = Ilast | |
1609 | then | |
1610 | Reason := CE_Overflow_Check_Failed; | |
1611 | else | |
1612 | Reason := CE_Range_Check_Failed; | |
1613 | end if; | |
1614 | ||
1615 | -- Raise CE if either conditions does not hold | |
1616 | ||
1617 | Insert_Action (Ck_Node, | |
1618 | Make_Raise_Constraint_Error (Loc, | |
05fcfafb | 1619 | Condition => Make_Op_Not (Loc, Make_And_Then (Loc, Lo_Chk, Hi_Chk)), |
5329ca64 | 1620 | Reason => Reason)); |
1621 | end Apply_Float_Conversion_Check; | |
1622 | ||
ee6ba406 | 1623 | ------------------------ |
1624 | -- Apply_Length_Check -- | |
1625 | ------------------------ | |
1626 | ||
1627 | procedure Apply_Length_Check | |
1628 | (Ck_Node : Node_Id; | |
1629 | Target_Typ : Entity_Id; | |
1630 | Source_Typ : Entity_Id := Empty) | |
1631 | is | |
1632 | begin | |
1633 | Apply_Selected_Length_Checks | |
1634 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
1635 | end Apply_Length_Check; | |
1636 | ||
1637 | ----------------------- | |
1638 | -- Apply_Range_Check -- | |
1639 | ----------------------- | |
1640 | ||
1641 | procedure Apply_Range_Check | |
1642 | (Ck_Node : Node_Id; | |
1643 | Target_Typ : Entity_Id; | |
1644 | Source_Typ : Entity_Id := Empty) | |
1645 | is | |
1646 | begin | |
1647 | Apply_Selected_Range_Checks | |
1648 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
1649 | end Apply_Range_Check; | |
1650 | ||
1651 | ------------------------------ | |
1652 | -- Apply_Scalar_Range_Check -- | |
1653 | ------------------------------ | |
1654 | ||
1655 | -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check | |
1656 | -- flag off if it is already set on. | |
1657 | ||
1658 | procedure Apply_Scalar_Range_Check | |
1659 | (Expr : Node_Id; | |
1660 | Target_Typ : Entity_Id; | |
1661 | Source_Typ : Entity_Id := Empty; | |
1662 | Fixed_Int : Boolean := False) | |
1663 | is | |
1664 | Parnt : constant Node_Id := Parent (Expr); | |
1665 | S_Typ : Entity_Id; | |
1666 | Arr : Node_Id := Empty; -- initialize to prevent warning | |
1667 | Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning | |
1668 | OK : Boolean; | |
1669 | ||
1670 | Is_Subscr_Ref : Boolean; | |
1671 | -- Set true if Expr is a subscript | |
1672 | ||
1673 | Is_Unconstrained_Subscr_Ref : Boolean; | |
1674 | -- Set true if Expr is a subscript of an unconstrained array. In this | |
1675 | -- case we do not attempt to do an analysis of the value against the | |
1676 | -- range of the subscript, since we don't know the actual subtype. | |
1677 | ||
1678 | Int_Real : Boolean; | |
1679 | -- Set to True if Expr should be regarded as a real value | |
1680 | -- even though the type of Expr might be discrete. | |
1681 | ||
1682 | procedure Bad_Value; | |
1683 | -- Procedure called if value is determined to be out of range | |
1684 | ||
9dfe12ae | 1685 | --------------- |
1686 | -- Bad_Value -- | |
1687 | --------------- | |
1688 | ||
ee6ba406 | 1689 | procedure Bad_Value is |
1690 | begin | |
1691 | Apply_Compile_Time_Constraint_Error | |
f15731c4 | 1692 | (Expr, "value not in range of}?", CE_Range_Check_Failed, |
ee6ba406 | 1693 | Ent => Target_Typ, |
1694 | Typ => Target_Typ); | |
1695 | end Bad_Value; | |
1696 | ||
9dfe12ae | 1697 | -- Start of processing for Apply_Scalar_Range_Check |
1698 | ||
ee6ba406 | 1699 | begin |
1700 | if Inside_A_Generic then | |
1701 | return; | |
1702 | ||
1703 | -- Return if check obviously not needed. Note that we do not check | |
1704 | -- for the expander being inactive, since this routine does not | |
1705 | -- insert any code, but it does generate useful warnings sometimes, | |
1706 | -- which we would like even if we are in semantics only mode. | |
1707 | ||
1708 | elsif Target_Typ = Any_Type | |
1709 | or else not Is_Scalar_Type (Target_Typ) | |
1710 | or else Raises_Constraint_Error (Expr) | |
1711 | then | |
1712 | return; | |
1713 | end if; | |
1714 | ||
1715 | -- Now, see if checks are suppressed | |
1716 | ||
1717 | Is_Subscr_Ref := | |
1718 | Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component; | |
1719 | ||
1720 | if Is_Subscr_Ref then | |
1721 | Arr := Prefix (Parnt); | |
1722 | Arr_Typ := Get_Actual_Subtype_If_Available (Arr); | |
1723 | end if; | |
1724 | ||
1725 | if not Do_Range_Check (Expr) then | |
1726 | ||
1727 | -- Subscript reference. Check for Index_Checks suppressed | |
1728 | ||
1729 | if Is_Subscr_Ref then | |
1730 | ||
1731 | -- Check array type and its base type | |
1732 | ||
1733 | if Index_Checks_Suppressed (Arr_Typ) | |
9dfe12ae | 1734 | or else Index_Checks_Suppressed (Base_Type (Arr_Typ)) |
ee6ba406 | 1735 | then |
1736 | return; | |
1737 | ||
1738 | -- Check array itself if it is an entity name | |
1739 | ||
1740 | elsif Is_Entity_Name (Arr) | |
9dfe12ae | 1741 | and then Index_Checks_Suppressed (Entity (Arr)) |
ee6ba406 | 1742 | then |
1743 | return; | |
1744 | ||
1745 | -- Check expression itself if it is an entity name | |
1746 | ||
1747 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 1748 | and then Index_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 1749 | then |
1750 | return; | |
1751 | end if; | |
1752 | ||
1753 | -- All other cases, check for Range_Checks suppressed | |
1754 | ||
1755 | else | |
1756 | -- Check target type and its base type | |
1757 | ||
1758 | if Range_Checks_Suppressed (Target_Typ) | |
9dfe12ae | 1759 | or else Range_Checks_Suppressed (Base_Type (Target_Typ)) |
ee6ba406 | 1760 | then |
1761 | return; | |
1762 | ||
1763 | -- Check expression itself if it is an entity name | |
1764 | ||
1765 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 1766 | and then Range_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 1767 | then |
1768 | return; | |
1769 | ||
1770 | -- If Expr is part of an assignment statement, then check | |
1771 | -- left side of assignment if it is an entity name. | |
1772 | ||
1773 | elsif Nkind (Parnt) = N_Assignment_Statement | |
1774 | and then Is_Entity_Name (Name (Parnt)) | |
9dfe12ae | 1775 | and then Range_Checks_Suppressed (Entity (Name (Parnt))) |
ee6ba406 | 1776 | then |
1777 | return; | |
1778 | end if; | |
1779 | end if; | |
1780 | end if; | |
1781 | ||
9dfe12ae | 1782 | -- Do not set range checks if they are killed |
1783 | ||
1784 | if Nkind (Expr) = N_Unchecked_Type_Conversion | |
1785 | and then Kill_Range_Check (Expr) | |
1786 | then | |
1787 | return; | |
1788 | end if; | |
1789 | ||
1790 | -- Do not set range checks for any values from System.Scalar_Values | |
1791 | -- since the whole idea of such values is to avoid checking them! | |
1792 | ||
1793 | if Is_Entity_Name (Expr) | |
1794 | and then Is_RTU (Scope (Entity (Expr)), System_Scalar_Values) | |
1795 | then | |
1796 | return; | |
1797 | end if; | |
1798 | ||
ee6ba406 | 1799 | -- Now see if we need a check |
1800 | ||
1801 | if No (Source_Typ) then | |
1802 | S_Typ := Etype (Expr); | |
1803 | else | |
1804 | S_Typ := Source_Typ; | |
1805 | end if; | |
1806 | ||
1807 | if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then | |
1808 | return; | |
1809 | end if; | |
1810 | ||
1811 | Is_Unconstrained_Subscr_Ref := | |
1812 | Is_Subscr_Ref and then not Is_Constrained (Arr_Typ); | |
1813 | ||
1814 | -- Always do a range check if the source type includes infinities | |
9dfe12ae | 1815 | -- and the target type does not include infinities. We do not do |
1816 | -- this if range checks are killed. | |
ee6ba406 | 1817 | |
1818 | if Is_Floating_Point_Type (S_Typ) | |
1819 | and then Has_Infinities (S_Typ) | |
1820 | and then not Has_Infinities (Target_Typ) | |
1821 | then | |
1822 | Enable_Range_Check (Expr); | |
1823 | end if; | |
1824 | ||
1825 | -- Return if we know expression is definitely in the range of | |
1826 | -- the target type as determined by Determine_Range. Right now | |
1827 | -- we only do this for discrete types, and not fixed-point or | |
1828 | -- floating-point types. | |
1829 | ||
f2a06be9 | 1830 | -- The additional less-precise tests below catch these cases |
ee6ba406 | 1831 | |
1832 | -- Note: skip this if we are given a source_typ, since the point | |
1833 | -- of supplying a Source_Typ is to stop us looking at the expression. | |
1834 | -- could sharpen this test to be out parameters only ??? | |
1835 | ||
1836 | if Is_Discrete_Type (Target_Typ) | |
1837 | and then Is_Discrete_Type (Etype (Expr)) | |
1838 | and then not Is_Unconstrained_Subscr_Ref | |
1839 | and then No (Source_Typ) | |
1840 | then | |
1841 | declare | |
1842 | Tlo : constant Node_Id := Type_Low_Bound (Target_Typ); | |
1843 | Thi : constant Node_Id := Type_High_Bound (Target_Typ); | |
1844 | Lo : Uint; | |
1845 | Hi : Uint; | |
1846 | ||
1847 | begin | |
1848 | if Compile_Time_Known_Value (Tlo) | |
1849 | and then Compile_Time_Known_Value (Thi) | |
1850 | then | |
9dfe12ae | 1851 | declare |
1852 | Lov : constant Uint := Expr_Value (Tlo); | |
1853 | Hiv : constant Uint := Expr_Value (Thi); | |
ee6ba406 | 1854 | |
9dfe12ae | 1855 | begin |
1856 | -- If range is null, we for sure have a constraint error | |
1857 | -- (we don't even need to look at the value involved, | |
1858 | -- since all possible values will raise CE). | |
1859 | ||
1860 | if Lov > Hiv then | |
1861 | Bad_Value; | |
1862 | return; | |
1863 | end if; | |
1864 | ||
1865 | -- Otherwise determine range of value | |
1866 | ||
1867 | Determine_Range (Expr, OK, Lo, Hi); | |
1868 | ||
1869 | if OK then | |
1870 | ||
1871 | -- If definitely in range, all OK | |
ee6ba406 | 1872 | |
ee6ba406 | 1873 | if Lo >= Lov and then Hi <= Hiv then |
1874 | return; | |
1875 | ||
9dfe12ae | 1876 | -- If definitely not in range, warn |
1877 | ||
ee6ba406 | 1878 | elsif Lov > Hi or else Hiv < Lo then |
1879 | Bad_Value; | |
1880 | return; | |
9dfe12ae | 1881 | |
1882 | -- Otherwise we don't know | |
1883 | ||
1884 | else | |
1885 | null; | |
ee6ba406 | 1886 | end if; |
9dfe12ae | 1887 | end if; |
1888 | end; | |
ee6ba406 | 1889 | end if; |
1890 | end; | |
1891 | end if; | |
1892 | ||
1893 | Int_Real := | |
1894 | Is_Floating_Point_Type (S_Typ) | |
1895 | or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int); | |
1896 | ||
1897 | -- Check if we can determine at compile time whether Expr is in the | |
9dfe12ae | 1898 | -- range of the target type. Note that if S_Typ is within the bounds |
1899 | -- of Target_Typ then this must be the case. This check is meaningful | |
1900 | -- only if this is not a conversion between integer and real types. | |
ee6ba406 | 1901 | |
1902 | if not Is_Unconstrained_Subscr_Ref | |
1903 | and then | |
1904 | Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ) | |
1905 | and then | |
1906 | (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int) | |
1907 | or else | |
1908 | Is_In_Range (Expr, Target_Typ, Fixed_Int, Int_Real)) | |
1909 | then | |
1910 | return; | |
1911 | ||
1912 | elsif Is_Out_Of_Range (Expr, Target_Typ, Fixed_Int, Int_Real) then | |
1913 | Bad_Value; | |
1914 | return; | |
1915 | ||
9dfe12ae | 1916 | -- In the floating-point case, we only do range checks if the |
1917 | -- type is constrained. We definitely do NOT want range checks | |
1918 | -- for unconstrained types, since we want to have infinities | |
ee6ba406 | 1919 | |
9dfe12ae | 1920 | elsif Is_Floating_Point_Type (S_Typ) then |
1921 | if Is_Constrained (S_Typ) then | |
1922 | Enable_Range_Check (Expr); | |
1923 | end if; | |
ee6ba406 | 1924 | |
9dfe12ae | 1925 | -- For all other cases we enable a range check unconditionally |
ee6ba406 | 1926 | |
1927 | else | |
1928 | Enable_Range_Check (Expr); | |
1929 | return; | |
1930 | end if; | |
ee6ba406 | 1931 | end Apply_Scalar_Range_Check; |
1932 | ||
1933 | ---------------------------------- | |
1934 | -- Apply_Selected_Length_Checks -- | |
1935 | ---------------------------------- | |
1936 | ||
1937 | procedure Apply_Selected_Length_Checks | |
1938 | (Ck_Node : Node_Id; | |
1939 | Target_Typ : Entity_Id; | |
1940 | Source_Typ : Entity_Id; | |
1941 | Do_Static : Boolean) | |
1942 | is | |
1943 | Cond : Node_Id; | |
1944 | R_Result : Check_Result; | |
1945 | R_Cno : Node_Id; | |
1946 | ||
1947 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
1948 | Checks_On : constant Boolean := | |
1949 | (not Index_Checks_Suppressed (Target_Typ)) | |
1950 | or else | |
1951 | (not Length_Checks_Suppressed (Target_Typ)); | |
1952 | ||
1953 | begin | |
f15731c4 | 1954 | if not Expander_Active then |
ee6ba406 | 1955 | return; |
1956 | end if; | |
1957 | ||
1958 | R_Result := | |
1959 | Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
1960 | ||
1961 | for J in 1 .. 2 loop | |
ee6ba406 | 1962 | R_Cno := R_Result (J); |
1963 | exit when No (R_Cno); | |
1964 | ||
1965 | -- A length check may mention an Itype which is attached to a | |
1966 | -- subsequent node. At the top level in a package this can cause | |
1967 | -- an order-of-elaboration problem, so we make sure that the itype | |
1968 | -- is referenced now. | |
1969 | ||
1970 | if Ekind (Current_Scope) = E_Package | |
1971 | and then Is_Compilation_Unit (Current_Scope) | |
1972 | then | |
1973 | Ensure_Defined (Target_Typ, Ck_Node); | |
1974 | ||
1975 | if Present (Source_Typ) then | |
1976 | Ensure_Defined (Source_Typ, Ck_Node); | |
1977 | ||
1978 | elsif Is_Itype (Etype (Ck_Node)) then | |
1979 | Ensure_Defined (Etype (Ck_Node), Ck_Node); | |
1980 | end if; | |
1981 | end if; | |
1982 | ||
1983 | -- If the item is a conditional raise of constraint error, | |
1984 | -- then have a look at what check is being performed and | |
1985 | -- ??? | |
1986 | ||
1987 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
1988 | and then Present (Condition (R_Cno)) | |
1989 | then | |
1990 | Cond := Condition (R_Cno); | |
1991 | ||
f15731c4 | 1992 | if not Has_Dynamic_Length_Check (Ck_Node) |
1993 | and then Checks_On | |
1994 | then | |
ee6ba406 | 1995 | Insert_Action (Ck_Node, R_Cno); |
1996 | ||
1997 | if not Do_Static then | |
1998 | Set_Has_Dynamic_Length_Check (Ck_Node); | |
1999 | end if; | |
ee6ba406 | 2000 | end if; |
2001 | ||
2002 | -- Output a warning if the condition is known to be True | |
2003 | ||
2004 | if Is_Entity_Name (Cond) | |
2005 | and then Entity (Cond) = Standard_True | |
2006 | then | |
2007 | Apply_Compile_Time_Constraint_Error | |
2008 | (Ck_Node, "wrong length for array of}?", | |
f15731c4 | 2009 | CE_Length_Check_Failed, |
ee6ba406 | 2010 | Ent => Target_Typ, |
2011 | Typ => Target_Typ); | |
2012 | ||
2013 | -- If we were only doing a static check, or if checks are not | |
2014 | -- on, then we want to delete the check, since it is not needed. | |
2015 | -- We do this by replacing the if statement by a null statement | |
2016 | ||
2017 | elsif Do_Static or else not Checks_On then | |
2018 | Rewrite (R_Cno, Make_Null_Statement (Loc)); | |
2019 | end if; | |
2020 | ||
2021 | else | |
2022 | Install_Static_Check (R_Cno, Loc); | |
2023 | end if; | |
2024 | ||
2025 | end loop; | |
2026 | ||
2027 | end Apply_Selected_Length_Checks; | |
2028 | ||
2029 | --------------------------------- | |
2030 | -- Apply_Selected_Range_Checks -- | |
2031 | --------------------------------- | |
2032 | ||
2033 | procedure Apply_Selected_Range_Checks | |
2034 | (Ck_Node : Node_Id; | |
2035 | Target_Typ : Entity_Id; | |
2036 | Source_Typ : Entity_Id; | |
2037 | Do_Static : Boolean) | |
2038 | is | |
2039 | Cond : Node_Id; | |
2040 | R_Result : Check_Result; | |
2041 | R_Cno : Node_Id; | |
2042 | ||
2043 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
2044 | Checks_On : constant Boolean := | |
2045 | (not Index_Checks_Suppressed (Target_Typ)) | |
2046 | or else | |
2047 | (not Range_Checks_Suppressed (Target_Typ)); | |
2048 | ||
2049 | begin | |
2050 | if not Expander_Active or else not Checks_On then | |
2051 | return; | |
2052 | end if; | |
2053 | ||
2054 | R_Result := | |
2055 | Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
2056 | ||
2057 | for J in 1 .. 2 loop | |
2058 | ||
2059 | R_Cno := R_Result (J); | |
2060 | exit when No (R_Cno); | |
2061 | ||
2062 | -- If the item is a conditional raise of constraint error, | |
2063 | -- then have a look at what check is being performed and | |
2064 | -- ??? | |
2065 | ||
2066 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
2067 | and then Present (Condition (R_Cno)) | |
2068 | then | |
2069 | Cond := Condition (R_Cno); | |
2070 | ||
2071 | if not Has_Dynamic_Range_Check (Ck_Node) then | |
2072 | Insert_Action (Ck_Node, R_Cno); | |
2073 | ||
2074 | if not Do_Static then | |
2075 | Set_Has_Dynamic_Range_Check (Ck_Node); | |
2076 | end if; | |
2077 | end if; | |
2078 | ||
2079 | -- Output a warning if the condition is known to be True | |
2080 | ||
2081 | if Is_Entity_Name (Cond) | |
2082 | and then Entity (Cond) = Standard_True | |
2083 | then | |
2084 | -- Since an N_Range is technically not an expression, we | |
2085 | -- have to set one of the bounds to C_E and then just flag | |
2086 | -- the N_Range. The warning message will point to the | |
2087 | -- lower bound and complain about a range, which seems OK. | |
2088 | ||
2089 | if Nkind (Ck_Node) = N_Range then | |
2090 | Apply_Compile_Time_Constraint_Error | |
2091 | (Low_Bound (Ck_Node), "static range out of bounds of}?", | |
f15731c4 | 2092 | CE_Range_Check_Failed, |
ee6ba406 | 2093 | Ent => Target_Typ, |
2094 | Typ => Target_Typ); | |
2095 | ||
2096 | Set_Raises_Constraint_Error (Ck_Node); | |
2097 | ||
2098 | else | |
2099 | Apply_Compile_Time_Constraint_Error | |
2100 | (Ck_Node, "static value out of range of}?", | |
f15731c4 | 2101 | CE_Range_Check_Failed, |
ee6ba406 | 2102 | Ent => Target_Typ, |
2103 | Typ => Target_Typ); | |
2104 | end if; | |
2105 | ||
2106 | -- If we were only doing a static check, or if checks are not | |
2107 | -- on, then we want to delete the check, since it is not needed. | |
2108 | -- We do this by replacing the if statement by a null statement | |
2109 | ||
2110 | elsif Do_Static or else not Checks_On then | |
2111 | Rewrite (R_Cno, Make_Null_Statement (Loc)); | |
2112 | end if; | |
2113 | ||
2114 | else | |
2115 | Install_Static_Check (R_Cno, Loc); | |
2116 | end if; | |
ee6ba406 | 2117 | end loop; |
ee6ba406 | 2118 | end Apply_Selected_Range_Checks; |
2119 | ||
2120 | ------------------------------- | |
2121 | -- Apply_Static_Length_Check -- | |
2122 | ------------------------------- | |
2123 | ||
2124 | procedure Apply_Static_Length_Check | |
2125 | (Expr : Node_Id; | |
2126 | Target_Typ : Entity_Id; | |
2127 | Source_Typ : Entity_Id := Empty) | |
2128 | is | |
2129 | begin | |
2130 | Apply_Selected_Length_Checks | |
2131 | (Expr, Target_Typ, Source_Typ, Do_Static => True); | |
2132 | end Apply_Static_Length_Check; | |
2133 | ||
2134 | ------------------------------------- | |
2135 | -- Apply_Subscript_Validity_Checks -- | |
2136 | ------------------------------------- | |
2137 | ||
2138 | procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is | |
2139 | Sub : Node_Id; | |
2140 | ||
2141 | begin | |
2142 | pragma Assert (Nkind (Expr) = N_Indexed_Component); | |
2143 | ||
2144 | -- Loop through subscripts | |
2145 | ||
2146 | Sub := First (Expressions (Expr)); | |
2147 | while Present (Sub) loop | |
2148 | ||
2149 | -- Check one subscript. Note that we do not worry about | |
2150 | -- enumeration type with holes, since we will convert the | |
2151 | -- value to a Pos value for the subscript, and that convert | |
2152 | -- will do the necessary validity check. | |
2153 | ||
2154 | Ensure_Valid (Sub, Holes_OK => True); | |
2155 | ||
2156 | -- Move to next subscript | |
2157 | ||
2158 | Sub := Next (Sub); | |
2159 | end loop; | |
2160 | end Apply_Subscript_Validity_Checks; | |
2161 | ||
2162 | ---------------------------------- | |
2163 | -- Apply_Type_Conversion_Checks -- | |
2164 | ---------------------------------- | |
2165 | ||
2166 | procedure Apply_Type_Conversion_Checks (N : Node_Id) is | |
2167 | Target_Type : constant Entity_Id := Etype (N); | |
2168 | Target_Base : constant Entity_Id := Base_Type (Target_Type); | |
9dfe12ae | 2169 | Expr : constant Node_Id := Expression (N); |
2170 | Expr_Type : constant Entity_Id := Etype (Expr); | |
ee6ba406 | 2171 | |
2172 | begin | |
2173 | if Inside_A_Generic then | |
2174 | return; | |
2175 | ||
f15731c4 | 2176 | -- Skip these checks if serious errors detected, there are some nasty |
ee6ba406 | 2177 | -- situations of incomplete trees that blow things up. |
2178 | ||
f15731c4 | 2179 | elsif Serious_Errors_Detected > 0 then |
ee6ba406 | 2180 | return; |
2181 | ||
2182 | -- Scalar type conversions of the form Target_Type (Expr) require | |
9dfe12ae | 2183 | -- a range check if we cannot be sure that Expr is in the base type |
2184 | -- of Target_Typ and also that Expr is in the range of Target_Typ. | |
2185 | -- These are not quite the same condition from an implementation | |
2186 | -- point of view, but clearly the second includes the first. | |
ee6ba406 | 2187 | |
2188 | elsif Is_Scalar_Type (Target_Type) then | |
2189 | declare | |
2190 | Conv_OK : constant Boolean := Conversion_OK (N); | |
2191 | -- If the Conversion_OK flag on the type conversion is set | |
2192 | -- and no floating point type is involved in the type conversion | |
2193 | -- then fixed point values must be read as integral values. | |
2194 | ||
5329ca64 | 2195 | Float_To_Int : constant Boolean := |
2196 | Is_Floating_Point_Type (Expr_Type) | |
2197 | and then Is_Integer_Type (Target_Type); | |
2198 | ||
ee6ba406 | 2199 | begin |
ee6ba406 | 2200 | if not Overflow_Checks_Suppressed (Target_Base) |
2201 | and then not In_Subrange_Of (Expr_Type, Target_Base, Conv_OK) | |
5329ca64 | 2202 | and then not Float_To_Int |
ee6ba406 | 2203 | then |
2204 | Set_Do_Overflow_Check (N); | |
2205 | end if; | |
2206 | ||
2207 | if not Range_Checks_Suppressed (Target_Type) | |
2208 | and then not Range_Checks_Suppressed (Expr_Type) | |
2209 | then | |
5329ca64 | 2210 | if Float_To_Int then |
2211 | Apply_Float_Conversion_Check (Expr, Target_Type); | |
2212 | else | |
2213 | Apply_Scalar_Range_Check | |
2214 | (Expr, Target_Type, Fixed_Int => Conv_OK); | |
2215 | end if; | |
ee6ba406 | 2216 | end if; |
2217 | end; | |
2218 | ||
2219 | elsif Comes_From_Source (N) | |
2220 | and then Is_Record_Type (Target_Type) | |
2221 | and then Is_Derived_Type (Target_Type) | |
2222 | and then not Is_Tagged_Type (Target_Type) | |
2223 | and then not Is_Constrained (Target_Type) | |
9dfe12ae | 2224 | and then Present (Stored_Constraint (Target_Type)) |
ee6ba406 | 2225 | then |
9dfe12ae | 2226 | -- An unconstrained derived type may have inherited discriminant |
2227 | -- Build an actual discriminant constraint list using the stored | |
ee6ba406 | 2228 | -- constraint, to verify that the expression of the parent type |
2229 | -- satisfies the constraints imposed by the (unconstrained!) | |
2230 | -- derived type. This applies to value conversions, not to view | |
2231 | -- conversions of tagged types. | |
2232 | ||
2233 | declare | |
9dfe12ae | 2234 | Loc : constant Source_Ptr := Sloc (N); |
2235 | Cond : Node_Id; | |
2236 | Constraint : Elmt_Id; | |
2237 | Discr_Value : Node_Id; | |
2238 | Discr : Entity_Id; | |
2239 | ||
2240 | New_Constraints : constant Elist_Id := New_Elmt_List; | |
2241 | Old_Constraints : constant Elist_Id := | |
2242 | Discriminant_Constraint (Expr_Type); | |
ee6ba406 | 2243 | |
2244 | begin | |
9dfe12ae | 2245 | Constraint := First_Elmt (Stored_Constraint (Target_Type)); |
ee6ba406 | 2246 | |
2247 | while Present (Constraint) loop | |
2248 | Discr_Value := Node (Constraint); | |
2249 | ||
2250 | if Is_Entity_Name (Discr_Value) | |
2251 | and then Ekind (Entity (Discr_Value)) = E_Discriminant | |
2252 | then | |
2253 | Discr := Corresponding_Discriminant (Entity (Discr_Value)); | |
2254 | ||
2255 | if Present (Discr) | |
2256 | and then Scope (Discr) = Base_Type (Expr_Type) | |
2257 | then | |
2258 | -- Parent is constrained by new discriminant. Obtain | |
2259 | -- Value of original discriminant in expression. If | |
2260 | -- the new discriminant has been used to constrain more | |
9dfe12ae | 2261 | -- than one of the stored discriminants, this will |
2262 | -- provide the required consistency check. | |
ee6ba406 | 2263 | |
2264 | Append_Elmt ( | |
2265 | Make_Selected_Component (Loc, | |
2266 | Prefix => | |
9dfe12ae | 2267 | Duplicate_Subexpr_No_Checks |
2268 | (Expr, Name_Req => True), | |
ee6ba406 | 2269 | Selector_Name => |
2270 | Make_Identifier (Loc, Chars (Discr))), | |
2271 | New_Constraints); | |
2272 | ||
2273 | else | |
2274 | -- Discriminant of more remote ancestor ??? | |
2275 | ||
2276 | return; | |
2277 | end if; | |
2278 | ||
2279 | -- Derived type definition has an explicit value for | |
9dfe12ae | 2280 | -- this stored discriminant. |
ee6ba406 | 2281 | |
2282 | else | |
2283 | Append_Elmt | |
9dfe12ae | 2284 | (Duplicate_Subexpr_No_Checks (Discr_Value), |
2285 | New_Constraints); | |
ee6ba406 | 2286 | end if; |
2287 | ||
2288 | Next_Elmt (Constraint); | |
2289 | end loop; | |
2290 | ||
2291 | -- Use the unconstrained expression type to retrieve the | |
2292 | -- discriminants of the parent, and apply momentarily the | |
2293 | -- discriminant constraint synthesized above. | |
2294 | ||
2295 | Set_Discriminant_Constraint (Expr_Type, New_Constraints); | |
2296 | Cond := Build_Discriminant_Checks (Expr, Expr_Type); | |
2297 | Set_Discriminant_Constraint (Expr_Type, Old_Constraints); | |
2298 | ||
2299 | Insert_Action (N, | |
f15731c4 | 2300 | Make_Raise_Constraint_Error (Loc, |
2301 | Condition => Cond, | |
2302 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 2303 | end; |
2304 | ||
9dfe12ae | 2305 | -- For arrays, conversions are applied during expansion, to take |
2306 | -- into accounts changes of representation. The checks become range | |
2307 | -- checks on the base type or length checks on the subtype, depending | |
2308 | -- on whether the target type is unconstrained or constrained. | |
ee6ba406 | 2309 | |
2310 | else | |
2311 | null; | |
2312 | end if; | |
ee6ba406 | 2313 | end Apply_Type_Conversion_Checks; |
2314 | ||
2315 | ---------------------------------------------- | |
2316 | -- Apply_Universal_Integer_Attribute_Checks -- | |
2317 | ---------------------------------------------- | |
2318 | ||
2319 | procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is | |
2320 | Loc : constant Source_Ptr := Sloc (N); | |
2321 | Typ : constant Entity_Id := Etype (N); | |
2322 | ||
2323 | begin | |
2324 | if Inside_A_Generic then | |
2325 | return; | |
2326 | ||
2327 | -- Nothing to do if checks are suppressed | |
2328 | ||
2329 | elsif Range_Checks_Suppressed (Typ) | |
2330 | and then Overflow_Checks_Suppressed (Typ) | |
2331 | then | |
2332 | return; | |
2333 | ||
2334 | -- Nothing to do if the attribute does not come from source. The | |
2335 | -- internal attributes we generate of this type do not need checks, | |
2336 | -- and furthermore the attempt to check them causes some circular | |
2337 | -- elaboration orders when dealing with packed types. | |
2338 | ||
2339 | elsif not Comes_From_Source (N) then | |
2340 | return; | |
2341 | ||
9dfe12ae | 2342 | -- If the prefix is a selected component that depends on a discriminant |
2343 | -- the check may improperly expose a discriminant instead of using | |
2344 | -- the bounds of the object itself. Set the type of the attribute to | |
2345 | -- the base type of the context, so that a check will be imposed when | |
2346 | -- needed (e.g. if the node appears as an index). | |
2347 | ||
2348 | elsif Nkind (Prefix (N)) = N_Selected_Component | |
2349 | and then Ekind (Typ) = E_Signed_Integer_Subtype | |
2350 | and then Depends_On_Discriminant (Scalar_Range (Typ)) | |
2351 | then | |
2352 | Set_Etype (N, Base_Type (Typ)); | |
2353 | ||
ee6ba406 | 2354 | -- Otherwise, replace the attribute node with a type conversion |
2355 | -- node whose expression is the attribute, retyped to universal | |
2356 | -- integer, and whose subtype mark is the target type. The call | |
2357 | -- to analyze this conversion will set range and overflow checks | |
2358 | -- as required for proper detection of an out of range value. | |
2359 | ||
2360 | else | |
2361 | Set_Etype (N, Universal_Integer); | |
2362 | Set_Analyzed (N, True); | |
2363 | ||
2364 | Rewrite (N, | |
2365 | Make_Type_Conversion (Loc, | |
2366 | Subtype_Mark => New_Occurrence_Of (Typ, Loc), | |
2367 | Expression => Relocate_Node (N))); | |
2368 | ||
2369 | Analyze_And_Resolve (N, Typ); | |
2370 | return; | |
2371 | end if; | |
2372 | ||
2373 | end Apply_Universal_Integer_Attribute_Checks; | |
2374 | ||
2375 | ------------------------------- | |
2376 | -- Build_Discriminant_Checks -- | |
2377 | ------------------------------- | |
2378 | ||
2379 | function Build_Discriminant_Checks | |
2380 | (N : Node_Id; | |
314a23b6 | 2381 | T_Typ : Entity_Id) return Node_Id |
ee6ba406 | 2382 | is |
2383 | Loc : constant Source_Ptr := Sloc (N); | |
2384 | Cond : Node_Id; | |
2385 | Disc : Elmt_Id; | |
2386 | Disc_Ent : Entity_Id; | |
9dfe12ae | 2387 | Dref : Node_Id; |
ee6ba406 | 2388 | Dval : Node_Id; |
2389 | ||
2390 | begin | |
2391 | Cond := Empty; | |
2392 | Disc := First_Elmt (Discriminant_Constraint (T_Typ)); | |
2393 | ||
9dfe12ae | 2394 | -- For a fully private type, use the discriminants of the parent type |
ee6ba406 | 2395 | |
2396 | if Is_Private_Type (T_Typ) | |
2397 | and then No (Full_View (T_Typ)) | |
2398 | then | |
2399 | Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ))); | |
2400 | else | |
2401 | Disc_Ent := First_Discriminant (T_Typ); | |
2402 | end if; | |
2403 | ||
2404 | while Present (Disc) loop | |
ee6ba406 | 2405 | Dval := Node (Disc); |
2406 | ||
2407 | if Nkind (Dval) = N_Identifier | |
2408 | and then Ekind (Entity (Dval)) = E_Discriminant | |
2409 | then | |
2410 | Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc); | |
2411 | else | |
9dfe12ae | 2412 | Dval := Duplicate_Subexpr_No_Checks (Dval); |
ee6ba406 | 2413 | end if; |
2414 | ||
00f91aef | 2415 | -- If we have an Unchecked_Union node, we can infer the discriminants |
2416 | -- of the node. | |
9dfe12ae | 2417 | |
00f91aef | 2418 | if Is_Unchecked_Union (Base_Type (T_Typ)) then |
2419 | Dref := New_Copy ( | |
2420 | Get_Discriminant_Value ( | |
2421 | First_Discriminant (T_Typ), | |
2422 | T_Typ, | |
2423 | Stored_Constraint (T_Typ))); | |
2424 | ||
2425 | else | |
2426 | Dref := | |
2427 | Make_Selected_Component (Loc, | |
2428 | Prefix => | |
2429 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), | |
2430 | Selector_Name => | |
2431 | Make_Identifier (Loc, Chars (Disc_Ent))); | |
2432 | ||
2433 | Set_Is_In_Discriminant_Check (Dref); | |
2434 | end if; | |
9dfe12ae | 2435 | |
ee6ba406 | 2436 | Evolve_Or_Else (Cond, |
2437 | Make_Op_Ne (Loc, | |
9dfe12ae | 2438 | Left_Opnd => Dref, |
ee6ba406 | 2439 | Right_Opnd => Dval)); |
2440 | ||
2441 | Next_Elmt (Disc); | |
2442 | Next_Discriminant (Disc_Ent); | |
2443 | end loop; | |
2444 | ||
2445 | return Cond; | |
2446 | end Build_Discriminant_Checks; | |
2447 | ||
13dbf220 | 2448 | ------------------ |
2449 | -- Check_Needed -- | |
2450 | ------------------ | |
2451 | ||
2452 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean is | |
2453 | N : Node_Id; | |
2454 | P : Node_Id; | |
2455 | K : Node_Kind; | |
2456 | L : Node_Id; | |
2457 | R : Node_Id; | |
2458 | ||
2459 | begin | |
2460 | -- Always check if not simple entity | |
2461 | ||
2462 | if Nkind (Nod) not in N_Has_Entity | |
2463 | or else not Comes_From_Source (Nod) | |
2464 | then | |
2465 | return True; | |
2466 | end if; | |
2467 | ||
2468 | -- Look up tree for short circuit | |
2469 | ||
2470 | N := Nod; | |
2471 | loop | |
2472 | P := Parent (N); | |
2473 | K := Nkind (P); | |
2474 | ||
2475 | if K not in N_Subexpr then | |
2476 | return True; | |
2477 | ||
2478 | -- Or/Or Else case, left operand must be equality test | |
2479 | ||
2480 | elsif K = N_Op_Or or else K = N_Or_Else then | |
2481 | exit when N = Right_Opnd (P) | |
2482 | and then Nkind (Left_Opnd (P)) = N_Op_Eq; | |
2483 | ||
38f5559f | 2484 | -- And/And then case, left operand must be inequality test |
13dbf220 | 2485 | |
2486 | elsif K = N_Op_And or else K = N_And_Then then | |
2487 | exit when N = Right_Opnd (P) | |
38f5559f | 2488 | and then Nkind (Left_Opnd (P)) = N_Op_Ne; |
13dbf220 | 2489 | end if; |
2490 | ||
2491 | N := P; | |
2492 | end loop; | |
2493 | ||
2494 | -- If we fall through the loop, then we have a conditional with an | |
2495 | -- appropriate test as its left operand. So test further. | |
2496 | ||
2497 | L := Left_Opnd (P); | |
2498 | ||
2499 | if Nkind (L) = N_Op_Not then | |
2500 | L := Right_Opnd (L); | |
2501 | end if; | |
2502 | ||
2503 | R := Right_Opnd (L); | |
2504 | L := Left_Opnd (L); | |
2505 | ||
2506 | -- Left operand of test must match original variable | |
2507 | ||
2508 | if Nkind (L) not in N_Has_Entity | |
2509 | or else Entity (L) /= Entity (Nod) | |
2510 | then | |
2511 | return True; | |
2512 | end if; | |
2513 | ||
2514 | -- Right operand of test mus be key value (zero or null) | |
2515 | ||
2516 | case Check is | |
2517 | when Access_Check => | |
2518 | if Nkind (R) /= N_Null then | |
2519 | return True; | |
2520 | end if; | |
2521 | ||
2522 | when Division_Check => | |
2523 | if not Compile_Time_Known_Value (R) | |
2524 | or else Expr_Value (R) /= Uint_0 | |
2525 | then | |
2526 | return True; | |
2527 | end if; | |
2528 | end case; | |
2529 | ||
2530 | -- Here we have the optimizable case, warn if not short-circuited | |
2531 | ||
2532 | if K = N_Op_And or else K = N_Op_Or then | |
2533 | case Check is | |
2534 | when Access_Check => | |
2535 | Error_Msg_N | |
2536 | ("Constraint_Error may be raised (access check)?", | |
2537 | Parent (Nod)); | |
2538 | when Division_Check => | |
2539 | Error_Msg_N | |
2540 | ("Constraint_Error may be raised (zero divide)?", | |
2541 | Parent (Nod)); | |
2542 | end case; | |
2543 | ||
2544 | if K = N_Op_And then | |
2545 | Error_Msg_N ("use `AND THEN` instead of AND?", P); | |
2546 | else | |
2547 | Error_Msg_N ("use `OR ELSE` instead of OR?", P); | |
2548 | end if; | |
2549 | ||
2550 | -- If not short-circuited, we need the ckeck | |
2551 | ||
2552 | return True; | |
2553 | ||
2554 | -- If short-circuited, we can omit the check | |
2555 | ||
2556 | else | |
2557 | return False; | |
2558 | end if; | |
2559 | end Check_Needed; | |
2560 | ||
ee6ba406 | 2561 | ----------------------------------- |
2562 | -- Check_Valid_Lvalue_Subscripts -- | |
2563 | ----------------------------------- | |
2564 | ||
2565 | procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is | |
2566 | begin | |
2567 | -- Skip this if range checks are suppressed | |
2568 | ||
2569 | if Range_Checks_Suppressed (Etype (Expr)) then | |
2570 | return; | |
2571 | ||
2572 | -- Only do this check for expressions that come from source. We | |
2573 | -- assume that expander generated assignments explicitly include | |
2574 | -- any necessary checks. Note that this is not just an optimization, | |
2575 | -- it avoids infinite recursions! | |
2576 | ||
2577 | elsif not Comes_From_Source (Expr) then | |
2578 | return; | |
2579 | ||
2580 | -- For a selected component, check the prefix | |
2581 | ||
2582 | elsif Nkind (Expr) = N_Selected_Component then | |
2583 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
2584 | return; | |
2585 | ||
2586 | -- Case of indexed component | |
2587 | ||
2588 | elsif Nkind (Expr) = N_Indexed_Component then | |
2589 | Apply_Subscript_Validity_Checks (Expr); | |
2590 | ||
2591 | -- Prefix may itself be or contain an indexed component, and | |
2592 | -- these subscripts need checking as well | |
2593 | ||
2594 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
2595 | end if; | |
2596 | end Check_Valid_Lvalue_Subscripts; | |
2597 | ||
fa7497e8 | 2598 | ---------------------------------- |
2599 | -- Null_Exclusion_Static_Checks -- | |
2600 | ---------------------------------- | |
2601 | ||
2602 | procedure Null_Exclusion_Static_Checks (N : Node_Id) is | |
2603 | K : constant Node_Kind := Nkind (N); | |
fa7497e8 | 2604 | Typ : Entity_Id; |
2605 | Related_Nod : Node_Id; | |
2606 | Has_Null_Exclusion : Boolean := False; | |
2607 | ||
13dbf220 | 2608 | begin |
2609 | pragma Assert (K = N_Parameter_Specification | |
2610 | or else K = N_Object_Declaration | |
2611 | or else K = N_Discriminant_Specification | |
2612 | or else K = N_Component_Declaration); | |
5329ca64 | 2613 | |
13dbf220 | 2614 | Typ := Etype (Defining_Identifier (N)); |
5329ca64 | 2615 | |
13dbf220 | 2616 | pragma Assert (Is_Access_Type (Typ) |
2617 | or else (K = N_Object_Declaration and then Is_Array_Type (Typ))); | |
fa7497e8 | 2618 | |
13dbf220 | 2619 | case K is |
2620 | when N_Parameter_Specification => | |
2621 | Related_Nod := Parameter_Type (N); | |
2622 | Has_Null_Exclusion := Null_Exclusion_Present (N); | |
fa7497e8 | 2623 | |
13dbf220 | 2624 | when N_Object_Declaration => |
2625 | Related_Nod := Object_Definition (N); | |
2626 | Has_Null_Exclusion := Null_Exclusion_Present (N); | |
fa7497e8 | 2627 | |
13dbf220 | 2628 | when N_Discriminant_Specification => |
2629 | Related_Nod := Discriminant_Type (N); | |
2630 | Has_Null_Exclusion := Null_Exclusion_Present (N); | |
5329ca64 | 2631 | |
13dbf220 | 2632 | when N_Component_Declaration => |
2633 | if Present (Access_Definition (Component_Definition (N))) then | |
2634 | Related_Nod := Component_Definition (N); | |
2635 | Has_Null_Exclusion := | |
2636 | Null_Exclusion_Present | |
2637 | (Access_Definition (Component_Definition (N))); | |
2638 | else | |
2639 | Related_Nod := | |
2640 | Subtype_Indication (Component_Definition (N)); | |
2641 | Has_Null_Exclusion := | |
2642 | Null_Exclusion_Present (Component_Definition (N)); | |
2643 | end if; | |
5329ca64 | 2644 | |
13dbf220 | 2645 | when others => |
2646 | raise Program_Error; | |
2647 | end case; | |
5329ca64 | 2648 | |
13dbf220 | 2649 | -- Enforce legality rule 3.10 (14/1): A null_exclusion is only allowed |
2650 | -- of the access subtype does not exclude null. | |
5329ca64 | 2651 | |
13dbf220 | 2652 | if Has_Null_Exclusion |
2653 | and then Can_Never_Be_Null (Typ) | |
5329ca64 | 2654 | |
13dbf220 | 2655 | -- No need to check itypes that have the null-excluding attribute |
2656 | -- because they were checked at their point of creation | |
5329ca64 | 2657 | |
13dbf220 | 2658 | and then not Is_Itype (Typ) |
2659 | then | |
2660 | Error_Msg_N | |
2661 | ("(Ada 2005) already a null-excluding type", Related_Nod); | |
2662 | end if; | |
5329ca64 | 2663 | |
13dbf220 | 2664 | -- Check that null-excluding objects are always initialized |
2665 | ||
2666 | if K = N_Object_Declaration | |
2667 | and then not Present (Expression (N)) | |
2668 | then | |
2669 | -- Add a an expression that assignates null. This node is needed | |
2670 | -- by Apply_Compile_Time_Constraint_Error, that will replace this | |
2671 | -- node by a Constraint_Error node. | |
2672 | ||
2673 | Set_Expression (N, Make_Null (Sloc (N))); | |
2674 | Set_Etype (Expression (N), Etype (Defining_Identifier (N))); | |
5329ca64 | 2675 | |
13dbf220 | 2676 | Apply_Compile_Time_Constraint_Error |
2677 | (N => Expression (N), | |
2678 | Msg => "(Ada 2005) null-excluding objects must be initialized?", | |
2679 | Reason => CE_Null_Not_Allowed); | |
2680 | end if; | |
5329ca64 | 2681 | |
13dbf220 | 2682 | -- Check that the null value is not used as a single expression to |
2683 | -- assignate a value to a null-excluding component, formal or object; | |
2684 | -- otherwise generate a warning message at the sloc of Related_Nod and | |
2685 | -- replace Expression (N) by an N_Contraint_Error node. | |
2686 | ||
2687 | declare | |
5329ca64 | 2688 | Expr : constant Node_Id := Expression (N); |
2689 | ||
2690 | begin | |
2691 | if Present (Expr) | |
2692 | and then Nkind (Expr) = N_Null | |
2693 | then | |
13dbf220 | 2694 | case K is |
2695 | when N_Discriminant_Specification | | |
2696 | N_Component_Declaration => | |
7189d17f | 2697 | Apply_Compile_Time_Constraint_Error |
2698 | (N => Expr, | |
2699 | Msg => "(Ada 2005) NULL not allowed in" | |
2700 | & " null-excluding components?", | |
13dbf220 | 2701 | Reason => CE_Null_Not_Allowed); |
5329ca64 | 2702 | |
13dbf220 | 2703 | when N_Parameter_Specification => |
7189d17f | 2704 | Apply_Compile_Time_Constraint_Error |
2705 | (N => Expr, | |
2706 | Msg => "(Ada 2005) NULL not allowed in" | |
2707 | & " null-excluding formals?", | |
13dbf220 | 2708 | Reason => CE_Null_Not_Allowed); |
5329ca64 | 2709 | |
13dbf220 | 2710 | when N_Object_Declaration => |
7189d17f | 2711 | Apply_Compile_Time_Constraint_Error |
2712 | (N => Expr, | |
2713 | Msg => "(Ada 2005) NULL not allowed in" | |
2714 | & " null-excluding objects?", | |
13dbf220 | 2715 | Reason => CE_Null_Not_Allowed); |
2716 | ||
2717 | when others => | |
2718 | null; | |
5329ca64 | 2719 | end case; |
2720 | end if; | |
13dbf220 | 2721 | end; |
fa7497e8 | 2722 | end Null_Exclusion_Static_Checks; |
2723 | ||
9dfe12ae | 2724 | ---------------------------------- |
2725 | -- Conditional_Statements_Begin -- | |
2726 | ---------------------------------- | |
2727 | ||
2728 | procedure Conditional_Statements_Begin is | |
2729 | begin | |
2730 | Saved_Checks_TOS := Saved_Checks_TOS + 1; | |
2731 | ||
2732 | -- If stack overflows, kill all checks, that way we know to | |
2733 | -- simply reset the number of saved checks to zero on return. | |
2734 | -- This should never occur in practice. | |
2735 | ||
2736 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
2737 | Kill_All_Checks; | |
2738 | ||
2739 | -- In the normal case, we just make a new stack entry saving | |
2740 | -- the current number of saved checks for a later restore. | |
2741 | ||
2742 | else | |
2743 | Saved_Checks_Stack (Saved_Checks_TOS) := Num_Saved_Checks; | |
2744 | ||
2745 | if Debug_Flag_CC then | |
2746 | w ("Conditional_Statements_Begin: Num_Saved_Checks = ", | |
2747 | Num_Saved_Checks); | |
2748 | end if; | |
2749 | end if; | |
2750 | end Conditional_Statements_Begin; | |
2751 | ||
2752 | -------------------------------- | |
2753 | -- Conditional_Statements_End -- | |
2754 | -------------------------------- | |
2755 | ||
2756 | procedure Conditional_Statements_End is | |
2757 | begin | |
2758 | pragma Assert (Saved_Checks_TOS > 0); | |
2759 | ||
2760 | -- If the saved checks stack overflowed, then we killed all | |
2761 | -- checks, so setting the number of saved checks back to | |
2762 | -- zero is correct. This should never occur in practice. | |
2763 | ||
2764 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
2765 | Num_Saved_Checks := 0; | |
2766 | ||
2767 | -- In the normal case, restore the number of saved checks | |
2768 | -- from the top stack entry. | |
2769 | ||
2770 | else | |
2771 | Num_Saved_Checks := Saved_Checks_Stack (Saved_Checks_TOS); | |
2772 | if Debug_Flag_CC then | |
2773 | w ("Conditional_Statements_End: Num_Saved_Checks = ", | |
2774 | Num_Saved_Checks); | |
2775 | end if; | |
2776 | end if; | |
2777 | ||
2778 | Saved_Checks_TOS := Saved_Checks_TOS - 1; | |
2779 | end Conditional_Statements_End; | |
2780 | ||
ee6ba406 | 2781 | --------------------- |
2782 | -- Determine_Range -- | |
2783 | --------------------- | |
2784 | ||
6af1bdbc | 2785 | Cache_Size : constant := 2 ** 10; |
ee6ba406 | 2786 | type Cache_Index is range 0 .. Cache_Size - 1; |
2787 | -- Determine size of below cache (power of 2 is more efficient!) | |
2788 | ||
2789 | Determine_Range_Cache_N : array (Cache_Index) of Node_Id; | |
2790 | Determine_Range_Cache_Lo : array (Cache_Index) of Uint; | |
2791 | Determine_Range_Cache_Hi : array (Cache_Index) of Uint; | |
2792 | -- The above arrays are used to implement a small direct cache | |
2793 | -- for Determine_Range calls. Because of the way Determine_Range | |
2794 | -- recursively traces subexpressions, and because overflow checking | |
2795 | -- calls the routine on the way up the tree, a quadratic behavior | |
2796 | -- can otherwise be encountered in large expressions. The cache | |
2797 | -- entry for node N is stored in the (N mod Cache_Size) entry, and | |
2798 | -- can be validated by checking the actual node value stored there. | |
2799 | ||
2800 | procedure Determine_Range | |
2801 | (N : Node_Id; | |
2802 | OK : out Boolean; | |
2803 | Lo : out Uint; | |
2804 | Hi : out Uint) | |
2805 | is | |
8880be85 | 2806 | Typ : constant Entity_Id := Etype (N); |
2807 | ||
2808 | Lo_Left : Uint; | |
2809 | Hi_Left : Uint; | |
2810 | -- Lo and Hi bounds of left operand | |
ee6ba406 | 2811 | |
ee6ba406 | 2812 | Lo_Right : Uint; |
ee6ba406 | 2813 | Hi_Right : Uint; |
8880be85 | 2814 | -- Lo and Hi bounds of right (or only) operand |
2815 | ||
2816 | Bound : Node_Id; | |
2817 | -- Temp variable used to hold a bound node | |
2818 | ||
2819 | Hbound : Uint; | |
2820 | -- High bound of base type of expression | |
2821 | ||
2822 | Lor : Uint; | |
2823 | Hir : Uint; | |
2824 | -- Refined values for low and high bounds, after tightening | |
2825 | ||
2826 | OK1 : Boolean; | |
2827 | -- Used in lower level calls to indicate if call succeeded | |
2828 | ||
2829 | Cindex : Cache_Index; | |
2830 | -- Used to search cache | |
ee6ba406 | 2831 | |
2832 | function OK_Operands return Boolean; | |
2833 | -- Used for binary operators. Determines the ranges of the left and | |
2834 | -- right operands, and if they are both OK, returns True, and puts | |
2835 | -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left | |
2836 | ||
2837 | ----------------- | |
2838 | -- OK_Operands -- | |
2839 | ----------------- | |
2840 | ||
2841 | function OK_Operands return Boolean is | |
2842 | begin | |
2843 | Determine_Range (Left_Opnd (N), OK1, Lo_Left, Hi_Left); | |
2844 | ||
2845 | if not OK1 then | |
2846 | return False; | |
2847 | end if; | |
2848 | ||
2849 | Determine_Range (Right_Opnd (N), OK1, Lo_Right, Hi_Right); | |
2850 | return OK1; | |
2851 | end OK_Operands; | |
2852 | ||
2853 | -- Start of processing for Determine_Range | |
2854 | ||
2855 | begin | |
2856 | -- Prevent junk warnings by initializing range variables | |
2857 | ||
2858 | Lo := No_Uint; | |
2859 | Hi := No_Uint; | |
2860 | Lor := No_Uint; | |
2861 | Hir := No_Uint; | |
2862 | ||
2863 | -- If the type is not discrete, or is undefined, then we can't | |
2864 | -- do anything about determining the range. | |
2865 | ||
2866 | if No (Typ) or else not Is_Discrete_Type (Typ) | |
2867 | or else Error_Posted (N) | |
2868 | then | |
2869 | OK := False; | |
2870 | return; | |
2871 | end if; | |
2872 | ||
2873 | -- For all other cases, we can determine the range | |
2874 | ||
2875 | OK := True; | |
2876 | ||
2877 | -- If value is compile time known, then the possible range is the | |
2878 | -- one value that we know this expression definitely has! | |
2879 | ||
2880 | if Compile_Time_Known_Value (N) then | |
2881 | Lo := Expr_Value (N); | |
2882 | Hi := Lo; | |
2883 | return; | |
2884 | end if; | |
2885 | ||
2886 | -- Return if already in the cache | |
2887 | ||
2888 | Cindex := Cache_Index (N mod Cache_Size); | |
2889 | ||
2890 | if Determine_Range_Cache_N (Cindex) = N then | |
2891 | Lo := Determine_Range_Cache_Lo (Cindex); | |
2892 | Hi := Determine_Range_Cache_Hi (Cindex); | |
2893 | return; | |
2894 | end if; | |
2895 | ||
2896 | -- Otherwise, start by finding the bounds of the type of the | |
2897 | -- expression, the value cannot be outside this range (if it | |
2898 | -- is, then we have an overflow situation, which is a separate | |
2899 | -- check, we are talking here only about the expression value). | |
2900 | ||
2901 | -- We use the actual bound unless it is dynamic, in which case | |
2902 | -- use the corresponding base type bound if possible. If we can't | |
8880be85 | 2903 | -- get a bound then we figure we can't determine the range (a |
2904 | -- peculiar case, that perhaps cannot happen, but there is no | |
2905 | -- point in bombing in this optimization circuit. | |
2906 | ||
2907 | -- First the low bound | |
ee6ba406 | 2908 | |
2909 | Bound := Type_Low_Bound (Typ); | |
2910 | ||
2911 | if Compile_Time_Known_Value (Bound) then | |
2912 | Lo := Expr_Value (Bound); | |
2913 | ||
2914 | elsif Compile_Time_Known_Value (Type_Low_Bound (Base_Type (Typ))) then | |
2915 | Lo := Expr_Value (Type_Low_Bound (Base_Type (Typ))); | |
2916 | ||
2917 | else | |
2918 | OK := False; | |
2919 | return; | |
2920 | end if; | |
2921 | ||
8880be85 | 2922 | -- Now the high bound |
2923 | ||
ee6ba406 | 2924 | Bound := Type_High_Bound (Typ); |
2925 | ||
8880be85 | 2926 | -- We need the high bound of the base type later on, and this should |
2927 | -- always be compile time known. Again, it is not clear that this | |
2928 | -- can ever be false, but no point in bombing. | |
ee6ba406 | 2929 | |
8880be85 | 2930 | if Compile_Time_Known_Value (Type_High_Bound (Base_Type (Typ))) then |
ee6ba406 | 2931 | Hbound := Expr_Value (Type_High_Bound (Base_Type (Typ))); |
2932 | Hi := Hbound; | |
2933 | ||
2934 | else | |
2935 | OK := False; | |
2936 | return; | |
2937 | end if; | |
2938 | ||
8880be85 | 2939 | -- If we have a static subtype, then that may have a tighter bound |
2940 | -- so use the upper bound of the subtype instead in this case. | |
2941 | ||
2942 | if Compile_Time_Known_Value (Bound) then | |
2943 | Hi := Expr_Value (Bound); | |
2944 | end if; | |
2945 | ||
ee6ba406 | 2946 | -- We may be able to refine this value in certain situations. If |
2947 | -- refinement is possible, then Lor and Hir are set to possibly | |
2948 | -- tighter bounds, and OK1 is set to True. | |
2949 | ||
2950 | case Nkind (N) is | |
2951 | ||
2952 | -- For unary plus, result is limited by range of operand | |
2953 | ||
2954 | when N_Op_Plus => | |
2955 | Determine_Range (Right_Opnd (N), OK1, Lor, Hir); | |
2956 | ||
2957 | -- For unary minus, determine range of operand, and negate it | |
2958 | ||
2959 | when N_Op_Minus => | |
2960 | Determine_Range (Right_Opnd (N), OK1, Lo_Right, Hi_Right); | |
2961 | ||
2962 | if OK1 then | |
2963 | Lor := -Hi_Right; | |
2964 | Hir := -Lo_Right; | |
2965 | end if; | |
2966 | ||
2967 | -- For binary addition, get range of each operand and do the | |
2968 | -- addition to get the result range. | |
2969 | ||
2970 | when N_Op_Add => | |
2971 | if OK_Operands then | |
2972 | Lor := Lo_Left + Lo_Right; | |
2973 | Hir := Hi_Left + Hi_Right; | |
2974 | end if; | |
2975 | ||
2976 | -- Division is tricky. The only case we consider is where the | |
2977 | -- right operand is a positive constant, and in this case we | |
2978 | -- simply divide the bounds of the left operand | |
2979 | ||
2980 | when N_Op_Divide => | |
2981 | if OK_Operands then | |
2982 | if Lo_Right = Hi_Right | |
2983 | and then Lo_Right > 0 | |
2984 | then | |
2985 | Lor := Lo_Left / Lo_Right; | |
2986 | Hir := Hi_Left / Lo_Right; | |
2987 | ||
2988 | else | |
2989 | OK1 := False; | |
2990 | end if; | |
2991 | end if; | |
2992 | ||
2993 | -- For binary subtraction, get range of each operand and do | |
2994 | -- the worst case subtraction to get the result range. | |
2995 | ||
2996 | when N_Op_Subtract => | |
2997 | if OK_Operands then | |
2998 | Lor := Lo_Left - Hi_Right; | |
2999 | Hir := Hi_Left - Lo_Right; | |
3000 | end if; | |
3001 | ||
3002 | -- For MOD, if right operand is a positive constant, then | |
3003 | -- result must be in the allowable range of mod results. | |
3004 | ||
3005 | when N_Op_Mod => | |
3006 | if OK_Operands then | |
9dfe12ae | 3007 | if Lo_Right = Hi_Right |
3008 | and then Lo_Right /= 0 | |
3009 | then | |
ee6ba406 | 3010 | if Lo_Right > 0 then |
3011 | Lor := Uint_0; | |
3012 | Hir := Lo_Right - 1; | |
3013 | ||
9dfe12ae | 3014 | else -- Lo_Right < 0 |
ee6ba406 | 3015 | Lor := Lo_Right + 1; |
3016 | Hir := Uint_0; | |
3017 | end if; | |
3018 | ||
3019 | else | |
3020 | OK1 := False; | |
3021 | end if; | |
3022 | end if; | |
3023 | ||
3024 | -- For REM, if right operand is a positive constant, then | |
3025 | -- result must be in the allowable range of mod results. | |
3026 | ||
3027 | when N_Op_Rem => | |
3028 | if OK_Operands then | |
9dfe12ae | 3029 | if Lo_Right = Hi_Right |
3030 | and then Lo_Right /= 0 | |
3031 | then | |
ee6ba406 | 3032 | declare |
3033 | Dval : constant Uint := (abs Lo_Right) - 1; | |
3034 | ||
3035 | begin | |
3036 | -- The sign of the result depends on the sign of the | |
3037 | -- dividend (but not on the sign of the divisor, hence | |
3038 | -- the abs operation above). | |
3039 | ||
3040 | if Lo_Left < 0 then | |
3041 | Lor := -Dval; | |
3042 | else | |
3043 | Lor := Uint_0; | |
3044 | end if; | |
3045 | ||
3046 | if Hi_Left < 0 then | |
3047 | Hir := Uint_0; | |
3048 | else | |
3049 | Hir := Dval; | |
3050 | end if; | |
3051 | end; | |
3052 | ||
3053 | else | |
3054 | OK1 := False; | |
3055 | end if; | |
3056 | end if; | |
3057 | ||
3058 | -- Attribute reference cases | |
3059 | ||
3060 | when N_Attribute_Reference => | |
3061 | case Attribute_Name (N) is | |
3062 | ||
3063 | -- For Pos/Val attributes, we can refine the range using the | |
3064 | -- possible range of values of the attribute expression | |
3065 | ||
3066 | when Name_Pos | Name_Val => | |
3067 | Determine_Range (First (Expressions (N)), OK1, Lor, Hir); | |
3068 | ||
3069 | -- For Length attribute, use the bounds of the corresponding | |
3070 | -- index type to refine the range. | |
3071 | ||
3072 | when Name_Length => | |
3073 | declare | |
3074 | Atyp : Entity_Id := Etype (Prefix (N)); | |
3075 | Inum : Nat; | |
3076 | Indx : Node_Id; | |
3077 | ||
3078 | LL, LU : Uint; | |
3079 | UL, UU : Uint; | |
3080 | ||
3081 | begin | |
3082 | if Is_Access_Type (Atyp) then | |
3083 | Atyp := Designated_Type (Atyp); | |
3084 | end if; | |
3085 | ||
3086 | -- For string literal, we know exact value | |
3087 | ||
3088 | if Ekind (Atyp) = E_String_Literal_Subtype then | |
3089 | OK := True; | |
3090 | Lo := String_Literal_Length (Atyp); | |
3091 | Hi := String_Literal_Length (Atyp); | |
3092 | return; | |
3093 | end if; | |
3094 | ||
3095 | -- Otherwise check for expression given | |
3096 | ||
3097 | if No (Expressions (N)) then | |
3098 | Inum := 1; | |
3099 | else | |
3100 | Inum := | |
3101 | UI_To_Int (Expr_Value (First (Expressions (N)))); | |
3102 | end if; | |
3103 | ||
3104 | Indx := First_Index (Atyp); | |
3105 | for J in 2 .. Inum loop | |
3106 | Indx := Next_Index (Indx); | |
3107 | end loop; | |
3108 | ||
3109 | Determine_Range | |
3110 | (Type_Low_Bound (Etype (Indx)), OK1, LL, LU); | |
3111 | ||
3112 | if OK1 then | |
3113 | Determine_Range | |
3114 | (Type_High_Bound (Etype (Indx)), OK1, UL, UU); | |
3115 | ||
3116 | if OK1 then | |
3117 | ||
3118 | -- The maximum value for Length is the biggest | |
3119 | -- possible gap between the values of the bounds. | |
3120 | -- But of course, this value cannot be negative. | |
3121 | ||
3122 | Hir := UI_Max (Uint_0, UU - LL); | |
3123 | ||
3124 | -- For constrained arrays, the minimum value for | |
3125 | -- Length is taken from the actual value of the | |
3126 | -- bounds, since the index will be exactly of | |
3127 | -- this subtype. | |
3128 | ||
3129 | if Is_Constrained (Atyp) then | |
3130 | Lor := UI_Max (Uint_0, UL - LU); | |
3131 | ||
3132 | -- For an unconstrained array, the minimum value | |
3133 | -- for length is always zero. | |
3134 | ||
3135 | else | |
3136 | Lor := Uint_0; | |
3137 | end if; | |
3138 | end if; | |
3139 | end if; | |
3140 | end; | |
3141 | ||
3142 | -- No special handling for other attributes | |
3143 | -- Probably more opportunities exist here ??? | |
3144 | ||
3145 | when others => | |
3146 | OK1 := False; | |
3147 | ||
3148 | end case; | |
3149 | ||
3150 | -- For type conversion from one discrete type to another, we | |
3151 | -- can refine the range using the converted value. | |
3152 | ||
3153 | when N_Type_Conversion => | |
3154 | Determine_Range (Expression (N), OK1, Lor, Hir); | |
3155 | ||
3156 | -- Nothing special to do for all other expression kinds | |
3157 | ||
3158 | when others => | |
3159 | OK1 := False; | |
3160 | Lor := No_Uint; | |
3161 | Hir := No_Uint; | |
3162 | end case; | |
3163 | ||
3164 | -- At this stage, if OK1 is true, then we know that the actual | |
3165 | -- result of the computed expression is in the range Lor .. Hir. | |
3166 | -- We can use this to restrict the possible range of results. | |
3167 | ||
3168 | if OK1 then | |
3169 | ||
3170 | -- If the refined value of the low bound is greater than the | |
3171 | -- type high bound, then reset it to the more restrictive | |
3172 | -- value. However, we do NOT do this for the case of a modular | |
3173 | -- type where the possible upper bound on the value is above the | |
3174 | -- base type high bound, because that means the result could wrap. | |
3175 | ||
3176 | if Lor > Lo | |
3177 | and then not (Is_Modular_Integer_Type (Typ) | |
3178 | and then Hir > Hbound) | |
3179 | then | |
3180 | Lo := Lor; | |
3181 | end if; | |
3182 | ||
3183 | -- Similarly, if the refined value of the high bound is less | |
3184 | -- than the value so far, then reset it to the more restrictive | |
3185 | -- value. Again, we do not do this if the refined low bound is | |
3186 | -- negative for a modular type, since this would wrap. | |
3187 | ||
3188 | if Hir < Hi | |
3189 | and then not (Is_Modular_Integer_Type (Typ) | |
3190 | and then Lor < Uint_0) | |
3191 | then | |
3192 | Hi := Hir; | |
3193 | end if; | |
3194 | end if; | |
3195 | ||
3196 | -- Set cache entry for future call and we are all done | |
3197 | ||
3198 | Determine_Range_Cache_N (Cindex) := N; | |
3199 | Determine_Range_Cache_Lo (Cindex) := Lo; | |
3200 | Determine_Range_Cache_Hi (Cindex) := Hi; | |
3201 | return; | |
3202 | ||
3203 | -- If any exception occurs, it means that we have some bug in the compiler | |
3204 | -- possibly triggered by a previous error, or by some unforseen peculiar | |
3205 | -- occurrence. However, this is only an optimization attempt, so there is | |
3206 | -- really no point in crashing the compiler. Instead we just decide, too | |
3207 | -- bad, we can't figure out a range in this case after all. | |
3208 | ||
3209 | exception | |
3210 | when others => | |
3211 | ||
3212 | -- Debug flag K disables this behavior (useful for debugging) | |
3213 | ||
3214 | if Debug_Flag_K then | |
3215 | raise; | |
3216 | else | |
3217 | OK := False; | |
3218 | Lo := No_Uint; | |
3219 | Hi := No_Uint; | |
3220 | return; | |
3221 | end if; | |
ee6ba406 | 3222 | end Determine_Range; |
3223 | ||
3224 | ------------------------------------ | |
3225 | -- Discriminant_Checks_Suppressed -- | |
3226 | ------------------------------------ | |
3227 | ||
3228 | function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is | |
3229 | begin | |
9dfe12ae | 3230 | if Present (E) then |
3231 | if Is_Unchecked_Union (E) then | |
3232 | return True; | |
3233 | elsif Checks_May_Be_Suppressed (E) then | |
3234 | return Is_Check_Suppressed (E, Discriminant_Check); | |
3235 | end if; | |
3236 | end if; | |
3237 | ||
3238 | return Scope_Suppress (Discriminant_Check); | |
ee6ba406 | 3239 | end Discriminant_Checks_Suppressed; |
3240 | ||
3241 | -------------------------------- | |
3242 | -- Division_Checks_Suppressed -- | |
3243 | -------------------------------- | |
3244 | ||
3245 | function Division_Checks_Suppressed (E : Entity_Id) return Boolean is | |
3246 | begin | |
9dfe12ae | 3247 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
3248 | return Is_Check_Suppressed (E, Division_Check); | |
3249 | else | |
3250 | return Scope_Suppress (Division_Check); | |
3251 | end if; | |
ee6ba406 | 3252 | end Division_Checks_Suppressed; |
3253 | ||
3254 | ----------------------------------- | |
3255 | -- Elaboration_Checks_Suppressed -- | |
3256 | ----------------------------------- | |
3257 | ||
3258 | function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is | |
3259 | begin | |
38f5559f | 3260 | -- The complication in this routine is that if we are in the dynamic |
3261 | -- model of elaboration, we also check All_Checks, since All_Checks | |
3262 | -- does not set Elaboration_Check explicitly. | |
3263 | ||
9dfe12ae | 3264 | if Present (E) then |
3265 | if Kill_Elaboration_Checks (E) then | |
3266 | return True; | |
38f5559f | 3267 | |
9dfe12ae | 3268 | elsif Checks_May_Be_Suppressed (E) then |
38f5559f | 3269 | if Is_Check_Suppressed (E, Elaboration_Check) then |
3270 | return True; | |
3271 | elsif Dynamic_Elaboration_Checks then | |
3272 | return Is_Check_Suppressed (E, All_Checks); | |
3273 | else | |
3274 | return False; | |
3275 | end if; | |
9dfe12ae | 3276 | end if; |
3277 | end if; | |
3278 | ||
38f5559f | 3279 | if Scope_Suppress (Elaboration_Check) then |
3280 | return True; | |
3281 | elsif Dynamic_Elaboration_Checks then | |
3282 | return Scope_Suppress (All_Checks); | |
3283 | else | |
3284 | return False; | |
3285 | end if; | |
ee6ba406 | 3286 | end Elaboration_Checks_Suppressed; |
3287 | ||
9dfe12ae | 3288 | --------------------------- |
3289 | -- Enable_Overflow_Check -- | |
3290 | --------------------------- | |
3291 | ||
3292 | procedure Enable_Overflow_Check (N : Node_Id) is | |
3293 | Typ : constant Entity_Id := Base_Type (Etype (N)); | |
3294 | Chk : Nat; | |
3295 | OK : Boolean; | |
3296 | Ent : Entity_Id; | |
3297 | Ofs : Uint; | |
3298 | Lo : Uint; | |
3299 | Hi : Uint; | |
ee6ba406 | 3300 | |
ee6ba406 | 3301 | begin |
9dfe12ae | 3302 | if Debug_Flag_CC then |
3303 | w ("Enable_Overflow_Check for node ", Int (N)); | |
3304 | Write_Str (" Source location = "); | |
3305 | wl (Sloc (N)); | |
3306 | pg (N); | |
ee6ba406 | 3307 | end if; |
ee6ba406 | 3308 | |
9dfe12ae | 3309 | -- Nothing to do if the range of the result is known OK. We skip |
3310 | -- this for conversions, since the caller already did the check, | |
3311 | -- and in any case the condition for deleting the check for a | |
3312 | -- type conversion is different in any case. | |
ee6ba406 | 3313 | |
9dfe12ae | 3314 | if Nkind (N) /= N_Type_Conversion then |
3315 | Determine_Range (N, OK, Lo, Hi); | |
ee6ba406 | 3316 | |
9dfe12ae | 3317 | -- Note in the test below that we assume that if a bound of the |
3318 | -- range is equal to that of the type. That's not quite accurate | |
3319 | -- but we do this for the following reasons: | |
ee6ba406 | 3320 | |
9dfe12ae | 3321 | -- a) The way that Determine_Range works, it will typically report |
3322 | -- the bounds of the value as being equal to the bounds of the | |
3323 | -- type, because it either can't tell anything more precise, or | |
3324 | -- does not think it is worth the effort to be more precise. | |
ee6ba406 | 3325 | |
9dfe12ae | 3326 | -- b) It is very unusual to have a situation in which this would |
3327 | -- generate an unnecessary overflow check (an example would be | |
3328 | -- a subtype with a range 0 .. Integer'Last - 1 to which the | |
3329 | -- literal value one is added. | |
ee6ba406 | 3330 | |
9dfe12ae | 3331 | -- c) The alternative is a lot of special casing in this routine |
3332 | -- which would partially duplicate Determine_Range processing. | |
ee6ba406 | 3333 | |
9dfe12ae | 3334 | if OK |
3335 | and then Lo > Expr_Value (Type_Low_Bound (Typ)) | |
3336 | and then Hi < Expr_Value (Type_High_Bound (Typ)) | |
3337 | then | |
3338 | if Debug_Flag_CC then | |
3339 | w ("No overflow check required"); | |
3340 | end if; | |
3341 | ||
3342 | return; | |
3343 | end if; | |
3344 | end if; | |
3345 | ||
3346 | -- If not in optimizing mode, set flag and we are done. We are also | |
3347 | -- done (and just set the flag) if the type is not a discrete type, | |
3348 | -- since it is not worth the effort to eliminate checks for other | |
3349 | -- than discrete types. In addition, we take this same path if we | |
3350 | -- have stored the maximum number of checks possible already (a | |
3351 | -- very unlikely situation, but we do not want to blow up!) | |
3352 | ||
3353 | if Optimization_Level = 0 | |
3354 | or else not Is_Discrete_Type (Etype (N)) | |
3355 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 3356 | then |
9dfe12ae | 3357 | Set_Do_Overflow_Check (N, True); |
3358 | ||
3359 | if Debug_Flag_CC then | |
3360 | w ("Optimization off"); | |
3361 | end if; | |
3362 | ||
ee6ba406 | 3363 | return; |
9dfe12ae | 3364 | end if; |
ee6ba406 | 3365 | |
9dfe12ae | 3366 | -- Otherwise evaluate and check the expression |
3367 | ||
3368 | Find_Check | |
3369 | (Expr => N, | |
3370 | Check_Type => 'O', | |
3371 | Target_Type => Empty, | |
3372 | Entry_OK => OK, | |
3373 | Check_Num => Chk, | |
3374 | Ent => Ent, | |
3375 | Ofs => Ofs); | |
3376 | ||
3377 | if Debug_Flag_CC then | |
3378 | w ("Called Find_Check"); | |
3379 | w (" OK = ", OK); | |
3380 | ||
3381 | if OK then | |
3382 | w (" Check_Num = ", Chk); | |
3383 | w (" Ent = ", Int (Ent)); | |
3384 | Write_Str (" Ofs = "); | |
3385 | pid (Ofs); | |
3386 | end if; | |
3387 | end if; | |
ee6ba406 | 3388 | |
9dfe12ae | 3389 | -- If check is not of form to optimize, then set flag and we are done |
3390 | ||
3391 | if not OK then | |
3392 | Set_Do_Overflow_Check (N, True); | |
ee6ba406 | 3393 | return; |
9dfe12ae | 3394 | end if; |
ee6ba406 | 3395 | |
9dfe12ae | 3396 | -- If check is already performed, then return without setting flag |
3397 | ||
3398 | if Chk /= 0 then | |
3399 | if Debug_Flag_CC then | |
3400 | w ("Check suppressed!"); | |
3401 | end if; | |
ee6ba406 | 3402 | |
ee6ba406 | 3403 | return; |
9dfe12ae | 3404 | end if; |
ee6ba406 | 3405 | |
9dfe12ae | 3406 | -- Here we will make a new entry for the new check |
3407 | ||
3408 | Set_Do_Overflow_Check (N, True); | |
3409 | Num_Saved_Checks := Num_Saved_Checks + 1; | |
3410 | Saved_Checks (Num_Saved_Checks) := | |
3411 | (Killed => False, | |
3412 | Entity => Ent, | |
3413 | Offset => Ofs, | |
3414 | Check_Type => 'O', | |
3415 | Target_Type => Empty); | |
3416 | ||
3417 | if Debug_Flag_CC then | |
3418 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
3419 | w (" Entity = ", Int (Ent)); | |
3420 | Write_Str (" Offset = "); | |
3421 | pid (Ofs); | |
3422 | w (" Check_Type = O"); | |
3423 | w (" Target_Type = Empty"); | |
3424 | end if; | |
ee6ba406 | 3425 | |
9dfe12ae | 3426 | -- If we get an exception, then something went wrong, probably because |
3427 | -- of an error in the structure of the tree due to an incorrect program. | |
3428 | -- Or it may be a bug in the optimization circuit. In either case the | |
3429 | -- safest thing is simply to set the check flag unconditionally. | |
3430 | ||
3431 | exception | |
3432 | when others => | |
3433 | Set_Do_Overflow_Check (N, True); | |
3434 | ||
3435 | if Debug_Flag_CC then | |
3436 | w (" exception occurred, overflow flag set"); | |
3437 | end if; | |
3438 | ||
3439 | return; | |
3440 | end Enable_Overflow_Check; | |
3441 | ||
3442 | ------------------------ | |
3443 | -- Enable_Range_Check -- | |
3444 | ------------------------ | |
3445 | ||
3446 | procedure Enable_Range_Check (N : Node_Id) is | |
3447 | Chk : Nat; | |
3448 | OK : Boolean; | |
3449 | Ent : Entity_Id; | |
3450 | Ofs : Uint; | |
3451 | Ttyp : Entity_Id; | |
3452 | P : Node_Id; | |
3453 | ||
3454 | begin | |
3455 | -- Return if unchecked type conversion with range check killed. | |
3456 | -- In this case we never set the flag (that's what Kill_Range_Check | |
3457 | -- is all about!) | |
3458 | ||
3459 | if Nkind (N) = N_Unchecked_Type_Conversion | |
3460 | and then Kill_Range_Check (N) | |
ee6ba406 | 3461 | then |
3462 | return; | |
9dfe12ae | 3463 | end if; |
ee6ba406 | 3464 | |
9dfe12ae | 3465 | -- Debug trace output |
ee6ba406 | 3466 | |
9dfe12ae | 3467 | if Debug_Flag_CC then |
3468 | w ("Enable_Range_Check for node ", Int (N)); | |
3469 | Write_Str (" Source location = "); | |
3470 | wl (Sloc (N)); | |
3471 | pg (N); | |
3472 | end if; | |
3473 | ||
3474 | -- If not in optimizing mode, set flag and we are done. We are also | |
3475 | -- done (and just set the flag) if the type is not a discrete type, | |
3476 | -- since it is not worth the effort to eliminate checks for other | |
3477 | -- than discrete types. In addition, we take this same path if we | |
3478 | -- have stored the maximum number of checks possible already (a | |
3479 | -- very unlikely situation, but we do not want to blow up!) | |
3480 | ||
3481 | if Optimization_Level = 0 | |
3482 | or else No (Etype (N)) | |
3483 | or else not Is_Discrete_Type (Etype (N)) | |
3484 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 3485 | then |
9dfe12ae | 3486 | Set_Do_Range_Check (N, True); |
3487 | ||
3488 | if Debug_Flag_CC then | |
3489 | w ("Optimization off"); | |
3490 | end if; | |
3491 | ||
ee6ba406 | 3492 | return; |
9dfe12ae | 3493 | end if; |
ee6ba406 | 3494 | |
9dfe12ae | 3495 | -- Otherwise find out the target type |
ee6ba406 | 3496 | |
9dfe12ae | 3497 | P := Parent (N); |
ee6ba406 | 3498 | |
9dfe12ae | 3499 | -- For assignment, use left side subtype |
3500 | ||
3501 | if Nkind (P) = N_Assignment_Statement | |
3502 | and then Expression (P) = N | |
3503 | then | |
3504 | Ttyp := Etype (Name (P)); | |
3505 | ||
3506 | -- For indexed component, use subscript subtype | |
3507 | ||
3508 | elsif Nkind (P) = N_Indexed_Component then | |
3509 | declare | |
3510 | Atyp : Entity_Id; | |
3511 | Indx : Node_Id; | |
3512 | Subs : Node_Id; | |
3513 | ||
3514 | begin | |
3515 | Atyp := Etype (Prefix (P)); | |
3516 | ||
3517 | if Is_Access_Type (Atyp) then | |
3518 | Atyp := Designated_Type (Atyp); | |
f07ea091 | 3519 | |
3520 | -- If the prefix is an access to an unconstrained array, | |
3521 | -- perform check unconditionally: it depends on the bounds | |
3522 | -- of an object and we cannot currently recognize whether | |
3523 | -- the test may be redundant. | |
3524 | ||
3525 | if not Is_Constrained (Atyp) then | |
3526 | Set_Do_Range_Check (N, True); | |
3527 | return; | |
3528 | end if; | |
7189d17f | 3529 | |
3530 | -- Ditto if the prefix is an explicit dereference whose | |
3531 | -- designated type is unconstrained. | |
3532 | ||
3533 | elsif Nkind (Prefix (P)) = N_Explicit_Dereference | |
3534 | and then not Is_Constrained (Atyp) | |
3535 | then | |
3536 | Set_Do_Range_Check (N, True); | |
3537 | return; | |
9dfe12ae | 3538 | end if; |
3539 | ||
3540 | Indx := First_Index (Atyp); | |
3541 | Subs := First (Expressions (P)); | |
3542 | loop | |
3543 | if Subs = N then | |
3544 | Ttyp := Etype (Indx); | |
3545 | exit; | |
3546 | end if; | |
3547 | ||
3548 | Next_Index (Indx); | |
3549 | Next (Subs); | |
3550 | end loop; | |
3551 | end; | |
3552 | ||
3553 | -- For now, ignore all other cases, they are not so interesting | |
3554 | ||
3555 | else | |
3556 | if Debug_Flag_CC then | |
3557 | w (" target type not found, flag set"); | |
3558 | end if; | |
3559 | ||
3560 | Set_Do_Range_Check (N, True); | |
3561 | return; | |
3562 | end if; | |
3563 | ||
3564 | -- Evaluate and check the expression | |
3565 | ||
3566 | Find_Check | |
3567 | (Expr => N, | |
3568 | Check_Type => 'R', | |
3569 | Target_Type => Ttyp, | |
3570 | Entry_OK => OK, | |
3571 | Check_Num => Chk, | |
3572 | Ent => Ent, | |
3573 | Ofs => Ofs); | |
3574 | ||
3575 | if Debug_Flag_CC then | |
3576 | w ("Called Find_Check"); | |
3577 | w ("Target_Typ = ", Int (Ttyp)); | |
3578 | w (" OK = ", OK); | |
3579 | ||
3580 | if OK then | |
3581 | w (" Check_Num = ", Chk); | |
3582 | w (" Ent = ", Int (Ent)); | |
3583 | Write_Str (" Ofs = "); | |
3584 | pid (Ofs); | |
3585 | end if; | |
3586 | end if; | |
3587 | ||
3588 | -- If check is not of form to optimize, then set flag and we are done | |
3589 | ||
3590 | if not OK then | |
3591 | if Debug_Flag_CC then | |
3592 | w (" expression not of optimizable type, flag set"); | |
3593 | end if; | |
3594 | ||
3595 | Set_Do_Range_Check (N, True); | |
3596 | return; | |
3597 | end if; | |
3598 | ||
3599 | -- If check is already performed, then return without setting flag | |
3600 | ||
3601 | if Chk /= 0 then | |
3602 | if Debug_Flag_CC then | |
3603 | w ("Check suppressed!"); | |
3604 | end if; | |
3605 | ||
3606 | return; | |
3607 | end if; | |
3608 | ||
3609 | -- Here we will make a new entry for the new check | |
3610 | ||
3611 | Set_Do_Range_Check (N, True); | |
3612 | Num_Saved_Checks := Num_Saved_Checks + 1; | |
3613 | Saved_Checks (Num_Saved_Checks) := | |
3614 | (Killed => False, | |
3615 | Entity => Ent, | |
3616 | Offset => Ofs, | |
3617 | Check_Type => 'R', | |
3618 | Target_Type => Ttyp); | |
3619 | ||
3620 | if Debug_Flag_CC then | |
3621 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
3622 | w (" Entity = ", Int (Ent)); | |
3623 | Write_Str (" Offset = "); | |
3624 | pid (Ofs); | |
3625 | w (" Check_Type = R"); | |
3626 | w (" Target_Type = ", Int (Ttyp)); | |
3627 | pg (Ttyp); | |
3628 | end if; | |
3629 | ||
3630 | -- If we get an exception, then something went wrong, probably because | |
3631 | -- of an error in the structure of the tree due to an incorrect program. | |
3632 | -- Or it may be a bug in the optimization circuit. In either case the | |
3633 | -- safest thing is simply to set the check flag unconditionally. | |
3634 | ||
3635 | exception | |
3636 | when others => | |
3637 | Set_Do_Range_Check (N, True); | |
3638 | ||
3639 | if Debug_Flag_CC then | |
3640 | w (" exception occurred, range flag set"); | |
3641 | end if; | |
3642 | ||
3643 | return; | |
3644 | end Enable_Range_Check; | |
3645 | ||
3646 | ------------------ | |
3647 | -- Ensure_Valid -- | |
3648 | ------------------ | |
3649 | ||
3650 | procedure Ensure_Valid (Expr : Node_Id; Holes_OK : Boolean := False) is | |
3651 | Typ : constant Entity_Id := Etype (Expr); | |
3652 | ||
3653 | begin | |
3654 | -- Ignore call if we are not doing any validity checking | |
3655 | ||
3656 | if not Validity_Checks_On then | |
3657 | return; | |
3658 | ||
3659 | -- Ignore call if range checks suppressed on entity in question | |
3660 | ||
3661 | elsif Is_Entity_Name (Expr) | |
3662 | and then Range_Checks_Suppressed (Entity (Expr)) | |
3663 | then | |
3664 | return; | |
3665 | ||
3666 | -- No check required if expression is from the expander, we assume | |
3667 | -- the expander will generate whatever checks are needed. Note that | |
3668 | -- this is not just an optimization, it avoids infinite recursions! | |
3669 | ||
3670 | -- Unchecked conversions must be checked, unless they are initialized | |
3671 | -- scalar values, as in a component assignment in an init proc. | |
3672 | ||
3673 | -- In addition, we force a check if Force_Validity_Checks is set | |
3674 | ||
3675 | elsif not Comes_From_Source (Expr) | |
3676 | and then not Force_Validity_Checks | |
3677 | and then (Nkind (Expr) /= N_Unchecked_Type_Conversion | |
3678 | or else Kill_Range_Check (Expr)) | |
3679 | then | |
3680 | return; | |
3681 | ||
3682 | -- No check required if expression is known to have valid value | |
3683 | ||
3684 | elsif Expr_Known_Valid (Expr) then | |
3685 | return; | |
3686 | ||
3687 | -- No check required if checks off | |
3688 | ||
3689 | elsif Range_Checks_Suppressed (Typ) then | |
3690 | return; | |
3691 | ||
3692 | -- Ignore case of enumeration with holes where the flag is set not | |
3693 | -- to worry about holes, since no special validity check is needed | |
3694 | ||
3695 | elsif Is_Enumeration_Type (Typ) | |
3696 | and then Has_Non_Standard_Rep (Typ) | |
3697 | and then Holes_OK | |
3698 | then | |
3699 | return; | |
3700 | ||
f2a06be9 | 3701 | -- No check required on the left-hand side of an assignment |
9dfe12ae | 3702 | |
3703 | elsif Nkind (Parent (Expr)) = N_Assignment_Statement | |
3704 | and then Expr = Name (Parent (Expr)) | |
3705 | then | |
3706 | return; | |
3707 | ||
38f5559f | 3708 | -- No check on a univeral real constant. The context will eventually |
3709 | -- convert it to a machine number for some target type, or report an | |
3710 | -- illegality. | |
3711 | ||
3712 | elsif Nkind (Expr) = N_Real_Literal | |
3713 | and then Etype (Expr) = Universal_Real | |
3714 | then | |
3715 | return; | |
3716 | ||
9dfe12ae | 3717 | -- An annoying special case. If this is an out parameter of a scalar |
3718 | -- type, then the value is not going to be accessed, therefore it is | |
3719 | -- inappropriate to do any validity check at the call site. | |
3720 | ||
3721 | else | |
3722 | -- Only need to worry about scalar types | |
3723 | ||
3724 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 3725 | declare |
3726 | P : Node_Id; | |
3727 | N : Node_Id; | |
3728 | E : Entity_Id; | |
3729 | F : Entity_Id; | |
3730 | A : Node_Id; | |
3731 | L : List_Id; | |
3732 | ||
3733 | begin | |
3734 | -- Find actual argument (which may be a parameter association) | |
3735 | -- and the parent of the actual argument (the call statement) | |
3736 | ||
3737 | N := Expr; | |
3738 | P := Parent (Expr); | |
3739 | ||
3740 | if Nkind (P) = N_Parameter_Association then | |
3741 | N := P; | |
3742 | P := Parent (N); | |
3743 | end if; | |
3744 | ||
3745 | -- Only need to worry if we are argument of a procedure | |
9dfe12ae | 3746 | -- call since functions don't have out parameters. If this |
3747 | -- is an indirect or dispatching call, get signature from | |
3748 | -- the subprogram type. | |
ee6ba406 | 3749 | |
3750 | if Nkind (P) = N_Procedure_Call_Statement then | |
3751 | L := Parameter_Associations (P); | |
9dfe12ae | 3752 | |
3753 | if Is_Entity_Name (Name (P)) then | |
3754 | E := Entity (Name (P)); | |
3755 | else | |
3756 | pragma Assert (Nkind (Name (P)) = N_Explicit_Dereference); | |
3757 | E := Etype (Name (P)); | |
3758 | end if; | |
ee6ba406 | 3759 | |
3760 | -- Only need to worry if there are indeed actuals, and | |
3761 | -- if this could be a procedure call, otherwise we cannot | |
3762 | -- get a match (either we are not an argument, or the | |
3763 | -- mode of the formal is not OUT). This test also filters | |
3764 | -- out the generic case. | |
3765 | ||
3766 | if Is_Non_Empty_List (L) | |
3767 | and then Is_Subprogram (E) | |
3768 | then | |
3769 | -- This is the loop through parameters, looking to | |
3770 | -- see if there is an OUT parameter for which we are | |
3771 | -- the argument. | |
3772 | ||
3773 | F := First_Formal (E); | |
3774 | A := First (L); | |
3775 | ||
3776 | while Present (F) loop | |
3777 | if Ekind (F) = E_Out_Parameter and then A = N then | |
3778 | return; | |
3779 | end if; | |
3780 | ||
3781 | Next_Formal (F); | |
3782 | Next (A); | |
3783 | end loop; | |
3784 | end if; | |
3785 | end if; | |
3786 | end; | |
3787 | end if; | |
3788 | end if; | |
3789 | ||
3790 | -- If we fall through, a validity check is required. Note that it would | |
3791 | -- not be good to set Do_Range_Check, even in contexts where this is | |
3792 | -- permissible, since this flag causes checking against the target type, | |
3793 | -- not the source type in contexts such as assignments | |
3794 | ||
3795 | Insert_Valid_Check (Expr); | |
3796 | end Ensure_Valid; | |
3797 | ||
3798 | ---------------------- | |
3799 | -- Expr_Known_Valid -- | |
3800 | ---------------------- | |
3801 | ||
3802 | function Expr_Known_Valid (Expr : Node_Id) return Boolean is | |
3803 | Typ : constant Entity_Id := Etype (Expr); | |
3804 | ||
3805 | begin | |
fa814356 | 3806 | -- Non-scalar types are always considered valid, since they never |
ee6ba406 | 3807 | -- give rise to the issues of erroneous or bounded error behavior |
3808 | -- that are the concern. In formal reference manual terms the | |
fa814356 | 3809 | -- notion of validity only applies to scalar types. Note that |
3810 | -- even when packed arrays are represented using modular types, | |
3811 | -- they are still arrays semantically, so they are also always | |
3812 | -- valid (in particular, the unused bits can be random rubbish | |
3813 | -- without affecting the validity of the array value). | |
ee6ba406 | 3814 | |
fa814356 | 3815 | if not Is_Scalar_Type (Typ) or else Is_Packed_Array_Type (Typ) then |
ee6ba406 | 3816 | return True; |
3817 | ||
3818 | -- If no validity checking, then everything is considered valid | |
3819 | ||
3820 | elsif not Validity_Checks_On then | |
3821 | return True; | |
3822 | ||
3823 | -- Floating-point types are considered valid unless floating-point | |
3824 | -- validity checks have been specifically turned on. | |
3825 | ||
3826 | elsif Is_Floating_Point_Type (Typ) | |
3827 | and then not Validity_Check_Floating_Point | |
3828 | then | |
3829 | return True; | |
3830 | ||
3831 | -- If the expression is the value of an object that is known to | |
3832 | -- be valid, then clearly the expression value itself is valid. | |
3833 | ||
3834 | elsif Is_Entity_Name (Expr) | |
3835 | and then Is_Known_Valid (Entity (Expr)) | |
3836 | then | |
3837 | return True; | |
3838 | ||
3839 | -- If the type is one for which all values are known valid, then | |
3840 | -- we are sure that the value is valid except in the slightly odd | |
3841 | -- case where the expression is a reference to a variable whose size | |
3842 | -- has been explicitly set to a value greater than the object size. | |
3843 | ||
3844 | elsif Is_Known_Valid (Typ) then | |
3845 | if Is_Entity_Name (Expr) | |
3846 | and then Ekind (Entity (Expr)) = E_Variable | |
3847 | and then Esize (Entity (Expr)) > Esize (Typ) | |
3848 | then | |
3849 | return False; | |
3850 | else | |
3851 | return True; | |
3852 | end if; | |
3853 | ||
3854 | -- Integer and character literals always have valid values, where | |
3855 | -- appropriate these will be range checked in any case. | |
3856 | ||
3857 | elsif Nkind (Expr) = N_Integer_Literal | |
3858 | or else | |
3859 | Nkind (Expr) = N_Character_Literal | |
3860 | then | |
3861 | return True; | |
3862 | ||
3863 | -- If we have a type conversion or a qualification of a known valid | |
3864 | -- value, then the result will always be valid. | |
3865 | ||
3866 | elsif Nkind (Expr) = N_Type_Conversion | |
3867 | or else | |
3868 | Nkind (Expr) = N_Qualified_Expression | |
3869 | then | |
3870 | return Expr_Known_Valid (Expression (Expr)); | |
3871 | ||
38f5559f | 3872 | -- The result of any operator is always considered valid, since we |
3873 | -- assume the necessary checks are done by the operator. For operators | |
3874 | -- on floating-point operations, we must also check when the operation | |
3875 | -- is the right-hand side of an assignment, or is an actual in a call. | |
ee6ba406 | 3876 | |
1d90d657 | 3877 | elsif |
3878 | Nkind (Expr) in N_Binary_Op or else Nkind (Expr) in N_Unary_Op | |
ee6ba406 | 3879 | then |
1d90d657 | 3880 | if Is_Floating_Point_Type (Typ) |
3881 | and then Validity_Check_Floating_Point | |
3882 | and then | |
3883 | (Nkind (Parent (Expr)) = N_Assignment_Statement | |
3884 | or else Nkind (Parent (Expr)) = N_Function_Call | |
3885 | or else Nkind (Parent (Expr)) = N_Parameter_Association) | |
3886 | then | |
3887 | return False; | |
3888 | else | |
3889 | return True; | |
3890 | end if; | |
3891 | ||
ee6ba406 | 3892 | -- For all other cases, we do not know the expression is valid |
3893 | ||
3894 | else | |
3895 | return False; | |
3896 | end if; | |
3897 | end Expr_Known_Valid; | |
3898 | ||
9dfe12ae | 3899 | ---------------- |
3900 | -- Find_Check -- | |
3901 | ---------------- | |
3902 | ||
3903 | procedure Find_Check | |
3904 | (Expr : Node_Id; | |
3905 | Check_Type : Character; | |
3906 | Target_Type : Entity_Id; | |
3907 | Entry_OK : out Boolean; | |
3908 | Check_Num : out Nat; | |
3909 | Ent : out Entity_Id; | |
3910 | Ofs : out Uint) | |
3911 | is | |
3912 | function Within_Range_Of | |
3913 | (Target_Type : Entity_Id; | |
314a23b6 | 3914 | Check_Type : Entity_Id) return Boolean; |
9dfe12ae | 3915 | -- Given a requirement for checking a range against Target_Type, and |
3916 | -- and a range Check_Type against which a check has already been made, | |
3917 | -- determines if the check against check type is sufficient to ensure | |
3918 | -- that no check against Target_Type is required. | |
3919 | ||
3920 | --------------------- | |
3921 | -- Within_Range_Of -- | |
3922 | --------------------- | |
3923 | ||
3924 | function Within_Range_Of | |
3925 | (Target_Type : Entity_Id; | |
314a23b6 | 3926 | Check_Type : Entity_Id) return Boolean |
9dfe12ae | 3927 | is |
3928 | begin | |
3929 | if Target_Type = Check_Type then | |
3930 | return True; | |
3931 | ||
3932 | else | |
3933 | declare | |
3934 | Tlo : constant Node_Id := Type_Low_Bound (Target_Type); | |
3935 | Thi : constant Node_Id := Type_High_Bound (Target_Type); | |
3936 | Clo : constant Node_Id := Type_Low_Bound (Check_Type); | |
3937 | Chi : constant Node_Id := Type_High_Bound (Check_Type); | |
3938 | ||
3939 | begin | |
3940 | if (Tlo = Clo | |
3941 | or else (Compile_Time_Known_Value (Tlo) | |
3942 | and then | |
3943 | Compile_Time_Known_Value (Clo) | |
3944 | and then | |
3945 | Expr_Value (Clo) >= Expr_Value (Tlo))) | |
3946 | and then | |
3947 | (Thi = Chi | |
3948 | or else (Compile_Time_Known_Value (Thi) | |
3949 | and then | |
3950 | Compile_Time_Known_Value (Chi) | |
3951 | and then | |
3952 | Expr_Value (Chi) <= Expr_Value (Clo))) | |
3953 | then | |
3954 | return True; | |
3955 | else | |
3956 | return False; | |
3957 | end if; | |
3958 | end; | |
3959 | end if; | |
3960 | end Within_Range_Of; | |
3961 | ||
3962 | -- Start of processing for Find_Check | |
3963 | ||
3964 | begin | |
f2a06be9 | 3965 | -- Establish default, to avoid warnings from GCC |
9dfe12ae | 3966 | |
3967 | Check_Num := 0; | |
3968 | ||
3969 | -- Case of expression is simple entity reference | |
3970 | ||
3971 | if Is_Entity_Name (Expr) then | |
3972 | Ent := Entity (Expr); | |
3973 | Ofs := Uint_0; | |
3974 | ||
3975 | -- Case of expression is entity + known constant | |
3976 | ||
3977 | elsif Nkind (Expr) = N_Op_Add | |
3978 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
3979 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
3980 | then | |
3981 | Ent := Entity (Left_Opnd (Expr)); | |
3982 | Ofs := Expr_Value (Right_Opnd (Expr)); | |
3983 | ||
3984 | -- Case of expression is entity - known constant | |
3985 | ||
3986 | elsif Nkind (Expr) = N_Op_Subtract | |
3987 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
3988 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
3989 | then | |
3990 | Ent := Entity (Left_Opnd (Expr)); | |
3991 | Ofs := UI_Negate (Expr_Value (Right_Opnd (Expr))); | |
3992 | ||
3993 | -- Any other expression is not of the right form | |
3994 | ||
3995 | else | |
3996 | Ent := Empty; | |
3997 | Ofs := Uint_0; | |
3998 | Entry_OK := False; | |
3999 | return; | |
4000 | end if; | |
4001 | ||
4002 | -- Come here with expression of appropriate form, check if | |
4003 | -- entity is an appropriate one for our purposes. | |
4004 | ||
4005 | if (Ekind (Ent) = E_Variable | |
4006 | or else | |
4007 | Ekind (Ent) = E_Constant | |
4008 | or else | |
4009 | Ekind (Ent) = E_Loop_Parameter | |
4010 | or else | |
4011 | Ekind (Ent) = E_In_Parameter) | |
4012 | and then not Is_Library_Level_Entity (Ent) | |
4013 | then | |
4014 | Entry_OK := True; | |
4015 | else | |
4016 | Entry_OK := False; | |
4017 | return; | |
4018 | end if; | |
4019 | ||
4020 | -- See if there is matching check already | |
4021 | ||
4022 | for J in reverse 1 .. Num_Saved_Checks loop | |
4023 | declare | |
4024 | SC : Saved_Check renames Saved_Checks (J); | |
4025 | ||
4026 | begin | |
4027 | if SC.Killed = False | |
4028 | and then SC.Entity = Ent | |
4029 | and then SC.Offset = Ofs | |
4030 | and then SC.Check_Type = Check_Type | |
4031 | and then Within_Range_Of (Target_Type, SC.Target_Type) | |
4032 | then | |
4033 | Check_Num := J; | |
4034 | return; | |
4035 | end if; | |
4036 | end; | |
4037 | end loop; | |
4038 | ||
4039 | -- If we fall through entry was not found | |
4040 | ||
4041 | Check_Num := 0; | |
4042 | return; | |
4043 | end Find_Check; | |
4044 | ||
4045 | --------------------------------- | |
4046 | -- Generate_Discriminant_Check -- | |
4047 | --------------------------------- | |
4048 | ||
4049 | -- Note: the code for this procedure is derived from the | |
4050 | -- emit_discriminant_check routine a-trans.c v1.659. | |
4051 | ||
4052 | procedure Generate_Discriminant_Check (N : Node_Id) is | |
4053 | Loc : constant Source_Ptr := Sloc (N); | |
4054 | Pref : constant Node_Id := Prefix (N); | |
4055 | Sel : constant Node_Id := Selector_Name (N); | |
4056 | ||
4057 | Orig_Comp : constant Entity_Id := | |
4058 | Original_Record_Component (Entity (Sel)); | |
4059 | -- The original component to be checked | |
4060 | ||
4061 | Discr_Fct : constant Entity_Id := | |
4062 | Discriminant_Checking_Func (Orig_Comp); | |
4063 | -- The discriminant checking function | |
4064 | ||
4065 | Discr : Entity_Id; | |
4066 | -- One discriminant to be checked in the type | |
4067 | ||
4068 | Real_Discr : Entity_Id; | |
4069 | -- Actual discriminant in the call | |
4070 | ||
4071 | Pref_Type : Entity_Id; | |
4072 | -- Type of relevant prefix (ignoring private/access stuff) | |
4073 | ||
4074 | Args : List_Id; | |
4075 | -- List of arguments for function call | |
4076 | ||
4077 | Formal : Entity_Id; | |
4078 | -- Keep track of the formal corresponding to the actual we build | |
4079 | -- for each discriminant, in order to be able to perform the | |
4080 | -- necessary type conversions. | |
4081 | ||
4082 | Scomp : Node_Id; | |
4083 | -- Selected component reference for checking function argument | |
4084 | ||
4085 | begin | |
4086 | Pref_Type := Etype (Pref); | |
4087 | ||
4088 | -- Force evaluation of the prefix, so that it does not get evaluated | |
4089 | -- twice (once for the check, once for the actual reference). Such a | |
4090 | -- double evaluation is always a potential source of inefficiency, | |
4091 | -- and is functionally incorrect in the volatile case, or when the | |
4092 | -- prefix may have side-effects. An entity or a component of an | |
4093 | -- entity requires no evaluation. | |
4094 | ||
4095 | if Is_Entity_Name (Pref) then | |
4096 | if Treat_As_Volatile (Entity (Pref)) then | |
4097 | Force_Evaluation (Pref, Name_Req => True); | |
4098 | end if; | |
4099 | ||
4100 | elsif Treat_As_Volatile (Etype (Pref)) then | |
4101 | Force_Evaluation (Pref, Name_Req => True); | |
4102 | ||
4103 | elsif Nkind (Pref) = N_Selected_Component | |
4104 | and then Is_Entity_Name (Prefix (Pref)) | |
4105 | then | |
4106 | null; | |
4107 | ||
4108 | else | |
4109 | Force_Evaluation (Pref, Name_Req => True); | |
4110 | end if; | |
4111 | ||
4112 | -- For a tagged type, use the scope of the original component to | |
4113 | -- obtain the type, because ??? | |
4114 | ||
4115 | if Is_Tagged_Type (Scope (Orig_Comp)) then | |
4116 | Pref_Type := Scope (Orig_Comp); | |
4117 | ||
4118 | -- For an untagged derived type, use the discriminants of the | |
4119 | -- parent which have been renamed in the derivation, possibly | |
4120 | -- by a one-to-many discriminant constraint. | |
4121 | -- For non-tagged type, initially get the Etype of the prefix | |
4122 | ||
4123 | else | |
4124 | if Is_Derived_Type (Pref_Type) | |
4125 | and then Number_Discriminants (Pref_Type) /= | |
4126 | Number_Discriminants (Etype (Base_Type (Pref_Type))) | |
4127 | then | |
4128 | Pref_Type := Etype (Base_Type (Pref_Type)); | |
4129 | end if; | |
4130 | end if; | |
4131 | ||
4132 | -- We definitely should have a checking function, This routine should | |
4133 | -- not be called if no discriminant checking function is present. | |
4134 | ||
4135 | pragma Assert (Present (Discr_Fct)); | |
4136 | ||
4137 | -- Create the list of the actual parameters for the call. This list | |
4138 | -- is the list of the discriminant fields of the record expression to | |
4139 | -- be discriminant checked. | |
4140 | ||
4141 | Args := New_List; | |
4142 | Formal := First_Formal (Discr_Fct); | |
4143 | Discr := First_Discriminant (Pref_Type); | |
4144 | while Present (Discr) loop | |
4145 | ||
4146 | -- If we have a corresponding discriminant field, and a parent | |
4147 | -- subtype is present, then we want to use the corresponding | |
4148 | -- discriminant since this is the one with the useful value. | |
4149 | ||
4150 | if Present (Corresponding_Discriminant (Discr)) | |
4151 | and then Ekind (Pref_Type) = E_Record_Type | |
4152 | and then Present (Parent_Subtype (Pref_Type)) | |
4153 | then | |
4154 | Real_Discr := Corresponding_Discriminant (Discr); | |
4155 | else | |
4156 | Real_Discr := Discr; | |
4157 | end if; | |
4158 | ||
4159 | -- Construct the reference to the discriminant | |
4160 | ||
4161 | Scomp := | |
4162 | Make_Selected_Component (Loc, | |
4163 | Prefix => | |
4164 | Unchecked_Convert_To (Pref_Type, | |
4165 | Duplicate_Subexpr (Pref)), | |
4166 | Selector_Name => New_Occurrence_Of (Real_Discr, Loc)); | |
4167 | ||
4168 | -- Manually analyze and resolve this selected component. We really | |
4169 | -- want it just as it appears above, and do not want the expander | |
4170 | -- playing discriminal games etc with this reference. Then we | |
4171 | -- append the argument to the list we are gathering. | |
4172 | ||
4173 | Set_Etype (Scomp, Etype (Real_Discr)); | |
4174 | Set_Analyzed (Scomp, True); | |
4175 | Append_To (Args, Convert_To (Etype (Formal), Scomp)); | |
4176 | ||
4177 | Next_Formal_With_Extras (Formal); | |
4178 | Next_Discriminant (Discr); | |
4179 | end loop; | |
4180 | ||
4181 | -- Now build and insert the call | |
4182 | ||
4183 | Insert_Action (N, | |
4184 | Make_Raise_Constraint_Error (Loc, | |
4185 | Condition => | |
4186 | Make_Function_Call (Loc, | |
4187 | Name => New_Occurrence_Of (Discr_Fct, Loc), | |
4188 | Parameter_Associations => Args), | |
4189 | Reason => CE_Discriminant_Check_Failed)); | |
4190 | end Generate_Discriminant_Check; | |
4191 | ||
5c99c290 | 4192 | --------------------------- |
4193 | -- Generate_Index_Checks -- | |
4194 | --------------------------- | |
9dfe12ae | 4195 | |
4196 | procedure Generate_Index_Checks (N : Node_Id) is | |
4197 | Loc : constant Source_Ptr := Sloc (N); | |
4198 | A : constant Node_Id := Prefix (N); | |
4199 | Sub : Node_Id; | |
4200 | Ind : Nat; | |
4201 | Num : List_Id; | |
4202 | ||
4203 | begin | |
4204 | Sub := First (Expressions (N)); | |
4205 | Ind := 1; | |
4206 | while Present (Sub) loop | |
4207 | if Do_Range_Check (Sub) then | |
4208 | Set_Do_Range_Check (Sub, False); | |
4209 | ||
4210 | -- Force evaluation except for the case of a simple name of | |
4211 | -- a non-volatile entity. | |
4212 | ||
4213 | if not Is_Entity_Name (Sub) | |
4214 | or else Treat_As_Volatile (Entity (Sub)) | |
4215 | then | |
4216 | Force_Evaluation (Sub); | |
4217 | end if; | |
4218 | ||
4219 | -- Generate a raise of constraint error with the appropriate | |
4220 | -- reason and a condition of the form: | |
4221 | ||
4222 | -- Base_Type(Sub) not in array'range (subscript) | |
4223 | ||
4224 | -- Note that the reason we generate the conversion to the | |
4225 | -- base type here is that we definitely want the range check | |
4226 | -- to take place, even if it looks like the subtype is OK. | |
4227 | -- Optimization considerations that allow us to omit the | |
4228 | -- check have already been taken into account in the setting | |
4229 | -- of the Do_Range_Check flag earlier on. | |
4230 | ||
4231 | if Ind = 1 then | |
4232 | Num := No_List; | |
4233 | else | |
4234 | Num := New_List (Make_Integer_Literal (Loc, Ind)); | |
4235 | end if; | |
4236 | ||
4237 | Insert_Action (N, | |
4238 | Make_Raise_Constraint_Error (Loc, | |
4239 | Condition => | |
4240 | Make_Not_In (Loc, | |
4241 | Left_Opnd => | |
4242 | Convert_To (Base_Type (Etype (Sub)), | |
4243 | Duplicate_Subexpr_Move_Checks (Sub)), | |
4244 | Right_Opnd => | |
4245 | Make_Attribute_Reference (Loc, | |
4246 | Prefix => Duplicate_Subexpr_Move_Checks (A), | |
4247 | Attribute_Name => Name_Range, | |
4248 | Expressions => Num)), | |
4249 | Reason => CE_Index_Check_Failed)); | |
4250 | end if; | |
4251 | ||
4252 | Ind := Ind + 1; | |
4253 | Next (Sub); | |
4254 | end loop; | |
4255 | end Generate_Index_Checks; | |
4256 | ||
4257 | -------------------------- | |
4258 | -- Generate_Range_Check -- | |
4259 | -------------------------- | |
4260 | ||
4261 | procedure Generate_Range_Check | |
4262 | (N : Node_Id; | |
4263 | Target_Type : Entity_Id; | |
4264 | Reason : RT_Exception_Code) | |
4265 | is | |
4266 | Loc : constant Source_Ptr := Sloc (N); | |
4267 | Source_Type : constant Entity_Id := Etype (N); | |
4268 | Source_Base_Type : constant Entity_Id := Base_Type (Source_Type); | |
4269 | Target_Base_Type : constant Entity_Id := Base_Type (Target_Type); | |
4270 | ||
4271 | begin | |
4272 | -- First special case, if the source type is already within the | |
4273 | -- range of the target type, then no check is needed (probably we | |
4274 | -- should have stopped Do_Range_Check from being set in the first | |
4275 | -- place, but better late than later in preventing junk code! | |
4276 | ||
4277 | -- We do NOT apply this if the source node is a literal, since in | |
4278 | -- this case the literal has already been labeled as having the | |
4279 | -- subtype of the target. | |
4280 | ||
4281 | if In_Subrange_Of (Source_Type, Target_Type) | |
4282 | and then not | |
4283 | (Nkind (N) = N_Integer_Literal | |
4284 | or else | |
4285 | Nkind (N) = N_Real_Literal | |
4286 | or else | |
4287 | Nkind (N) = N_Character_Literal | |
4288 | or else | |
4289 | (Is_Entity_Name (N) | |
4290 | and then Ekind (Entity (N)) = E_Enumeration_Literal)) | |
4291 | then | |
4292 | return; | |
4293 | end if; | |
4294 | ||
4295 | -- We need a check, so force evaluation of the node, so that it does | |
4296 | -- not get evaluated twice (once for the check, once for the actual | |
4297 | -- reference). Such a double evaluation is always a potential source | |
4298 | -- of inefficiency, and is functionally incorrect in the volatile case. | |
4299 | ||
4300 | if not Is_Entity_Name (N) | |
4301 | or else Treat_As_Volatile (Entity (N)) | |
4302 | then | |
4303 | Force_Evaluation (N); | |
4304 | end if; | |
4305 | ||
4306 | -- The easiest case is when Source_Base_Type and Target_Base_Type | |
4307 | -- are the same since in this case we can simply do a direct | |
4308 | -- check of the value of N against the bounds of Target_Type. | |
4309 | ||
4310 | -- [constraint_error when N not in Target_Type] | |
4311 | ||
4312 | -- Note: this is by far the most common case, for example all cases of | |
4313 | -- checks on the RHS of assignments are in this category, but not all | |
4314 | -- cases are like this. Notably conversions can involve two types. | |
4315 | ||
4316 | if Source_Base_Type = Target_Base_Type then | |
4317 | Insert_Action (N, | |
4318 | Make_Raise_Constraint_Error (Loc, | |
4319 | Condition => | |
4320 | Make_Not_In (Loc, | |
4321 | Left_Opnd => Duplicate_Subexpr (N), | |
4322 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
4323 | Reason => Reason)); | |
4324 | ||
4325 | -- Next test for the case where the target type is within the bounds | |
4326 | -- of the base type of the source type, since in this case we can | |
4327 | -- simply convert these bounds to the base type of T to do the test. | |
4328 | ||
4329 | -- [constraint_error when N not in | |
4330 | -- Source_Base_Type (Target_Type'First) | |
4331 | -- .. | |
4332 | -- Source_Base_Type(Target_Type'Last))] | |
4333 | ||
f2a06be9 | 4334 | -- The conversions will always work and need no check |
9dfe12ae | 4335 | |
4336 | elsif In_Subrange_Of (Target_Type, Source_Base_Type) then | |
4337 | Insert_Action (N, | |
4338 | Make_Raise_Constraint_Error (Loc, | |
4339 | Condition => | |
4340 | Make_Not_In (Loc, | |
4341 | Left_Opnd => Duplicate_Subexpr (N), | |
4342 | ||
4343 | Right_Opnd => | |
4344 | Make_Range (Loc, | |
4345 | Low_Bound => | |
4346 | Convert_To (Source_Base_Type, | |
4347 | Make_Attribute_Reference (Loc, | |
4348 | Prefix => | |
4349 | New_Occurrence_Of (Target_Type, Loc), | |
4350 | Attribute_Name => Name_First)), | |
4351 | ||
4352 | High_Bound => | |
4353 | Convert_To (Source_Base_Type, | |
4354 | Make_Attribute_Reference (Loc, | |
4355 | Prefix => | |
4356 | New_Occurrence_Of (Target_Type, Loc), | |
4357 | Attribute_Name => Name_Last)))), | |
4358 | Reason => Reason)); | |
4359 | ||
4360 | -- Note that at this stage we now that the Target_Base_Type is | |
4361 | -- not in the range of the Source_Base_Type (since even the | |
4362 | -- Target_Type itself is not in this range). It could still be | |
4363 | -- the case that the Source_Type is in range of the target base | |
4364 | -- type, since we have not checked that case. | |
4365 | ||
4366 | -- If that is the case, we can freely convert the source to the | |
4367 | -- target, and then test the target result against the bounds. | |
4368 | ||
4369 | elsif In_Subrange_Of (Source_Type, Target_Base_Type) then | |
4370 | ||
4371 | -- We make a temporary to hold the value of the converted | |
4372 | -- value (converted to the base type), and then we will | |
4373 | -- do the test against this temporary. | |
4374 | ||
4375 | -- Tnn : constant Target_Base_Type := Target_Base_Type (N); | |
4376 | -- [constraint_error when Tnn not in Target_Type] | |
4377 | ||
4378 | -- Then the conversion itself is replaced by an occurrence of Tnn | |
4379 | ||
4380 | declare | |
4381 | Tnn : constant Entity_Id := | |
4382 | Make_Defining_Identifier (Loc, | |
4383 | Chars => New_Internal_Name ('T')); | |
4384 | ||
4385 | begin | |
4386 | Insert_Actions (N, New_List ( | |
4387 | Make_Object_Declaration (Loc, | |
4388 | Defining_Identifier => Tnn, | |
4389 | Object_Definition => | |
4390 | New_Occurrence_Of (Target_Base_Type, Loc), | |
4391 | Constant_Present => True, | |
4392 | Expression => | |
4393 | Make_Type_Conversion (Loc, | |
4394 | Subtype_Mark => New_Occurrence_Of (Target_Base_Type, Loc), | |
4395 | Expression => Duplicate_Subexpr (N))), | |
4396 | ||
4397 | Make_Raise_Constraint_Error (Loc, | |
4398 | Condition => | |
4399 | Make_Not_In (Loc, | |
4400 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
4401 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
4402 | ||
4403 | Reason => Reason))); | |
4404 | ||
4405 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
4406 | end; | |
4407 | ||
4408 | -- At this stage, we know that we have two scalar types, which are | |
4409 | -- directly convertible, and where neither scalar type has a base | |
4410 | -- range that is in the range of the other scalar type. | |
4411 | ||
4412 | -- The only way this can happen is with a signed and unsigned type. | |
4413 | -- So test for these two cases: | |
4414 | ||
4415 | else | |
4416 | -- Case of the source is unsigned and the target is signed | |
4417 | ||
4418 | if Is_Unsigned_Type (Source_Base_Type) | |
4419 | and then not Is_Unsigned_Type (Target_Base_Type) | |
4420 | then | |
4421 | -- If the source is unsigned and the target is signed, then we | |
4422 | -- know that the source is not shorter than the target (otherwise | |
4423 | -- the source base type would be in the target base type range). | |
4424 | ||
4425 | -- In other words, the unsigned type is either the same size | |
4426 | -- as the target, or it is larger. It cannot be smaller. | |
4427 | ||
4428 | pragma Assert | |
4429 | (Esize (Source_Base_Type) >= Esize (Target_Base_Type)); | |
4430 | ||
4431 | -- We only need to check the low bound if the low bound of the | |
4432 | -- target type is non-negative. If the low bound of the target | |
4433 | -- type is negative, then we know that we will fit fine. | |
4434 | ||
4435 | -- If the high bound of the target type is negative, then we | |
4436 | -- know we have a constraint error, since we can't possibly | |
4437 | -- have a negative source. | |
4438 | ||
4439 | -- With these two checks out of the way, we can do the check | |
4440 | -- using the source type safely | |
4441 | ||
4442 | -- This is definitely the most annoying case! | |
4443 | ||
4444 | -- [constraint_error | |
4445 | -- when (Target_Type'First >= 0 | |
4446 | -- and then | |
4447 | -- N < Source_Base_Type (Target_Type'First)) | |
4448 | -- or else Target_Type'Last < 0 | |
4449 | -- or else N > Source_Base_Type (Target_Type'Last)]; | |
4450 | ||
4451 | -- We turn off all checks since we know that the conversions | |
4452 | -- will work fine, given the guards for negative values. | |
4453 | ||
4454 | Insert_Action (N, | |
4455 | Make_Raise_Constraint_Error (Loc, | |
4456 | Condition => | |
4457 | Make_Or_Else (Loc, | |
4458 | Make_Or_Else (Loc, | |
4459 | Left_Opnd => | |
4460 | Make_And_Then (Loc, | |
4461 | Left_Opnd => Make_Op_Ge (Loc, | |
4462 | Left_Opnd => | |
4463 | Make_Attribute_Reference (Loc, | |
4464 | Prefix => | |
4465 | New_Occurrence_Of (Target_Type, Loc), | |
4466 | Attribute_Name => Name_First), | |
4467 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
4468 | ||
4469 | Right_Opnd => | |
4470 | Make_Op_Lt (Loc, | |
4471 | Left_Opnd => Duplicate_Subexpr (N), | |
4472 | Right_Opnd => | |
4473 | Convert_To (Source_Base_Type, | |
4474 | Make_Attribute_Reference (Loc, | |
4475 | Prefix => | |
4476 | New_Occurrence_Of (Target_Type, Loc), | |
4477 | Attribute_Name => Name_First)))), | |
4478 | ||
4479 | Right_Opnd => | |
4480 | Make_Op_Lt (Loc, | |
4481 | Left_Opnd => | |
4482 | Make_Attribute_Reference (Loc, | |
4483 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
4484 | Attribute_Name => Name_Last), | |
4485 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0))), | |
4486 | ||
4487 | Right_Opnd => | |
4488 | Make_Op_Gt (Loc, | |
4489 | Left_Opnd => Duplicate_Subexpr (N), | |
4490 | Right_Opnd => | |
4491 | Convert_To (Source_Base_Type, | |
4492 | Make_Attribute_Reference (Loc, | |
4493 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
4494 | Attribute_Name => Name_Last)))), | |
4495 | ||
4496 | Reason => Reason), | |
4497 | Suppress => All_Checks); | |
4498 | ||
4499 | -- Only remaining possibility is that the source is signed and | |
4500 | -- the target is unsigned | |
4501 | ||
4502 | else | |
4503 | pragma Assert (not Is_Unsigned_Type (Source_Base_Type) | |
4504 | and then Is_Unsigned_Type (Target_Base_Type)); | |
4505 | ||
4506 | -- If the source is signed and the target is unsigned, then | |
4507 | -- we know that the target is not shorter than the source | |
4508 | -- (otherwise the target base type would be in the source | |
4509 | -- base type range). | |
4510 | ||
4511 | -- In other words, the unsigned type is either the same size | |
4512 | -- as the target, or it is larger. It cannot be smaller. | |
4513 | ||
4514 | -- Clearly we have an error if the source value is negative | |
4515 | -- since no unsigned type can have negative values. If the | |
4516 | -- source type is non-negative, then the check can be done | |
4517 | -- using the target type. | |
4518 | ||
4519 | -- Tnn : constant Target_Base_Type (N) := Target_Type; | |
4520 | ||
4521 | -- [constraint_error | |
4522 | -- when N < 0 or else Tnn not in Target_Type]; | |
4523 | ||
4524 | -- We turn off all checks for the conversion of N to the | |
4525 | -- target base type, since we generate the explicit check | |
4526 | -- to ensure that the value is non-negative | |
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 => | |
4543 | New_Occurrence_Of (Target_Base_Type, Loc), | |
4544 | Expression => Duplicate_Subexpr (N))), | |
4545 | ||
4546 | Make_Raise_Constraint_Error (Loc, | |
4547 | Condition => | |
4548 | Make_Or_Else (Loc, | |
4549 | Left_Opnd => | |
4550 | Make_Op_Lt (Loc, | |
4551 | Left_Opnd => Duplicate_Subexpr (N), | |
4552 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
4553 | ||
4554 | Right_Opnd => | |
4555 | Make_Not_In (Loc, | |
4556 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
4557 | Right_Opnd => | |
4558 | New_Occurrence_Of (Target_Type, Loc))), | |
4559 | ||
4560 | Reason => Reason)), | |
4561 | Suppress => All_Checks); | |
4562 | ||
4563 | -- Set the Etype explicitly, because Insert_Actions may | |
4564 | -- have placed the declaration in the freeze list for an | |
4565 | -- enclosing construct, and thus it is not analyzed yet. | |
4566 | ||
4567 | Set_Etype (Tnn, Target_Base_Type); | |
4568 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
4569 | end; | |
4570 | end if; | |
4571 | end if; | |
4572 | end Generate_Range_Check; | |
4573 | ||
ee6ba406 | 4574 | --------------------- |
4575 | -- Get_Discriminal -- | |
4576 | --------------------- | |
4577 | ||
4578 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is | |
4579 | Loc : constant Source_Ptr := Sloc (E); | |
4580 | D : Entity_Id; | |
4581 | Sc : Entity_Id; | |
4582 | ||
4583 | begin | |
4584 | -- The entity E is the type of a private component of the protected | |
4585 | -- type, or the type of a renaming of that component within a protected | |
4586 | -- operation of that type. | |
4587 | ||
4588 | Sc := Scope (E); | |
4589 | ||
4590 | if Ekind (Sc) /= E_Protected_Type then | |
4591 | Sc := Scope (Sc); | |
4592 | ||
4593 | if Ekind (Sc) /= E_Protected_Type then | |
4594 | return Bound; | |
4595 | end if; | |
4596 | end if; | |
4597 | ||
4598 | D := First_Discriminant (Sc); | |
4599 | ||
4600 | while Present (D) | |
4601 | and then Chars (D) /= Chars (Bound) | |
4602 | loop | |
4603 | Next_Discriminant (D); | |
4604 | end loop; | |
4605 | ||
4606 | return New_Occurrence_Of (Discriminal (D), Loc); | |
4607 | end Get_Discriminal; | |
4608 | ||
4609 | ------------------ | |
4610 | -- Guard_Access -- | |
4611 | ------------------ | |
4612 | ||
4613 | function Guard_Access | |
4614 | (Cond : Node_Id; | |
4615 | Loc : Source_Ptr; | |
314a23b6 | 4616 | Ck_Node : Node_Id) return Node_Id |
ee6ba406 | 4617 | is |
4618 | begin | |
4619 | if Nkind (Cond) = N_Or_Else then | |
4620 | Set_Paren_Count (Cond, 1); | |
4621 | end if; | |
4622 | ||
4623 | if Nkind (Ck_Node) = N_Allocator then | |
4624 | return Cond; | |
4625 | else | |
4626 | return | |
4627 | Make_And_Then (Loc, | |
4628 | Left_Opnd => | |
4629 | Make_Op_Ne (Loc, | |
9dfe12ae | 4630 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), |
ee6ba406 | 4631 | Right_Opnd => Make_Null (Loc)), |
4632 | Right_Opnd => Cond); | |
4633 | end if; | |
4634 | end Guard_Access; | |
4635 | ||
4636 | ----------------------------- | |
4637 | -- Index_Checks_Suppressed -- | |
4638 | ----------------------------- | |
4639 | ||
4640 | function Index_Checks_Suppressed (E : Entity_Id) return Boolean is | |
4641 | begin | |
9dfe12ae | 4642 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
4643 | return Is_Check_Suppressed (E, Index_Check); | |
4644 | else | |
4645 | return Scope_Suppress (Index_Check); | |
4646 | end if; | |
ee6ba406 | 4647 | end Index_Checks_Suppressed; |
4648 | ||
4649 | ---------------- | |
4650 | -- Initialize -- | |
4651 | ---------------- | |
4652 | ||
4653 | procedure Initialize is | |
4654 | begin | |
4655 | for J in Determine_Range_Cache_N'Range loop | |
4656 | Determine_Range_Cache_N (J) := Empty; | |
4657 | end loop; | |
4658 | end Initialize; | |
4659 | ||
4660 | ------------------------- | |
4661 | -- Insert_Range_Checks -- | |
4662 | ------------------------- | |
4663 | ||
4664 | procedure Insert_Range_Checks | |
4665 | (Checks : Check_Result; | |
4666 | Node : Node_Id; | |
4667 | Suppress_Typ : Entity_Id; | |
4668 | Static_Sloc : Source_Ptr := No_Location; | |
4669 | Flag_Node : Node_Id := Empty; | |
4670 | Do_Before : Boolean := False) | |
4671 | is | |
4672 | Internal_Flag_Node : Node_Id := Flag_Node; | |
4673 | Internal_Static_Sloc : Source_Ptr := Static_Sloc; | |
4674 | ||
4675 | Check_Node : Node_Id; | |
4676 | Checks_On : constant Boolean := | |
4677 | (not Index_Checks_Suppressed (Suppress_Typ)) | |
4678 | or else | |
4679 | (not Range_Checks_Suppressed (Suppress_Typ)); | |
4680 | ||
4681 | begin | |
4682 | -- For now we just return if Checks_On is false, however this should | |
4683 | -- be enhanced to check for an always True value in the condition | |
4684 | -- and to generate a compilation warning??? | |
4685 | ||
4686 | if not Expander_Active or else not Checks_On then | |
4687 | return; | |
4688 | end if; | |
4689 | ||
4690 | if Static_Sloc = No_Location then | |
4691 | Internal_Static_Sloc := Sloc (Node); | |
4692 | end if; | |
4693 | ||
4694 | if No (Flag_Node) then | |
4695 | Internal_Flag_Node := Node; | |
4696 | end if; | |
4697 | ||
4698 | for J in 1 .. 2 loop | |
4699 | exit when No (Checks (J)); | |
4700 | ||
4701 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
4702 | and then Present (Condition (Checks (J))) | |
4703 | then | |
4704 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
4705 | Check_Node := Checks (J); | |
4706 | Mark_Rewrite_Insertion (Check_Node); | |
4707 | ||
4708 | if Do_Before then | |
4709 | Insert_Before_And_Analyze (Node, Check_Node); | |
4710 | else | |
4711 | Insert_After_And_Analyze (Node, Check_Node); | |
4712 | end if; | |
4713 | ||
4714 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
4715 | end if; | |
4716 | ||
4717 | else | |
4718 | Check_Node := | |
f15731c4 | 4719 | Make_Raise_Constraint_Error (Internal_Static_Sloc, |
4720 | Reason => CE_Range_Check_Failed); | |
ee6ba406 | 4721 | Mark_Rewrite_Insertion (Check_Node); |
4722 | ||
4723 | if Do_Before then | |
4724 | Insert_Before_And_Analyze (Node, Check_Node); | |
4725 | else | |
4726 | Insert_After_And_Analyze (Node, Check_Node); | |
4727 | end if; | |
4728 | end if; | |
4729 | end loop; | |
4730 | end Insert_Range_Checks; | |
4731 | ||
4732 | ------------------------ | |
4733 | -- Insert_Valid_Check -- | |
4734 | ------------------------ | |
4735 | ||
4736 | procedure Insert_Valid_Check (Expr : Node_Id) is | |
4737 | Loc : constant Source_Ptr := Sloc (Expr); | |
8b718dab | 4738 | Exp : Node_Id; |
ee6ba406 | 4739 | |
4740 | begin | |
4741 | -- Do not insert if checks off, or if not checking validity | |
4742 | ||
4743 | if Range_Checks_Suppressed (Etype (Expr)) | |
4744 | or else (not Validity_Checks_On) | |
4745 | then | |
8b718dab | 4746 | return; |
4747 | end if; | |
ee6ba406 | 4748 | |
8b718dab | 4749 | -- If we have a checked conversion, then validity check applies to |
4750 | -- the expression inside the conversion, not the result, since if | |
4751 | -- the expression inside is valid, then so is the conversion result. | |
ee6ba406 | 4752 | |
8b718dab | 4753 | Exp := Expr; |
4754 | while Nkind (Exp) = N_Type_Conversion loop | |
4755 | Exp := Expression (Exp); | |
4756 | end loop; | |
4757 | ||
f15731c4 | 4758 | -- Insert the validity check. Note that we do this with validity |
8b718dab | 4759 | -- checks turned off, to avoid recursion, we do not want validity |
4760 | -- checks on the validity checking code itself! | |
4761 | ||
4762 | Validity_Checks_On := False; | |
4763 | Insert_Action | |
4764 | (Expr, | |
4765 | Make_Raise_Constraint_Error (Loc, | |
4766 | Condition => | |
4767 | Make_Op_Not (Loc, | |
4768 | Right_Opnd => | |
4769 | Make_Attribute_Reference (Loc, | |
4770 | Prefix => | |
9dfe12ae | 4771 | Duplicate_Subexpr_No_Checks (Exp, Name_Req => True), |
f15731c4 | 4772 | Attribute_Name => Name_Valid)), |
4773 | Reason => CE_Invalid_Data), | |
8b718dab | 4774 | Suppress => All_Checks); |
05fcfafb | 4775 | |
4776 | -- If the expression is a a reference to an element of a bit-packed | |
4777 | -- array, it is rewritten as a renaming declaration. If the expression | |
4778 | -- is an actual in a call, it has not been expanded, waiting for the | |
4779 | -- proper point at which to do it. The same happens with renamings, so | |
4780 | -- that we have to force the expansion now. This non-local complication | |
4781 | -- is due to code in exp_ch2,adb, exp_ch4.adb and exp_ch6.adb. | |
4782 | ||
4783 | if Is_Entity_Name (Exp) | |
4784 | and then Nkind (Parent (Entity (Exp))) = N_Object_Renaming_Declaration | |
4785 | then | |
4786 | declare | |
4787 | Old_Exp : constant Node_Id := Name (Parent (Entity (Exp))); | |
4788 | begin | |
4789 | if Nkind (Old_Exp) = N_Indexed_Component | |
4790 | and then Is_Bit_Packed_Array (Etype (Prefix (Old_Exp))) | |
4791 | then | |
4792 | Expand_Packed_Element_Reference (Old_Exp); | |
4793 | end if; | |
4794 | end; | |
4795 | end if; | |
4796 | ||
8b718dab | 4797 | Validity_Checks_On := True; |
ee6ba406 | 4798 | end Insert_Valid_Check; |
4799 | ||
fa7497e8 | 4800 | ---------------------------------- |
4801 | -- Install_Null_Excluding_Check -- | |
4802 | ---------------------------------- | |
4803 | ||
4804 | procedure Install_Null_Excluding_Check (N : Node_Id) is | |
4805 | Loc : constant Source_Ptr := Sloc (N); | |
4806 | Etyp : constant Entity_Id := Etype (N); | |
4807 | ||
4808 | begin | |
4809 | pragma Assert (Is_Access_Type (Etyp)); | |
4810 | ||
05fcfafb | 4811 | -- Don't need access check if: |
4812 | -- 1) we are analyzing a generic | |
4813 | -- 2) it is known to be non-null | |
4814 | -- 3) the check was suppressed on the type | |
4815 | -- 4) This is an attribute reference that returns an access type. | |
fa7497e8 | 4816 | |
4817 | if Inside_A_Generic | |
4818 | or else Access_Checks_Suppressed (Etyp) | |
4819 | then | |
4820 | return; | |
05fcfafb | 4821 | elsif Nkind (N) = N_Attribute_Reference |
4822 | and then | |
4823 | (Attribute_Name (N) = Name_Access | |
4824 | or else | |
4825 | Attribute_Name (N) = Name_Unchecked_Access | |
4826 | or else | |
4827 | Attribute_Name (N) = Name_Unrestricted_Access) | |
4828 | then | |
4829 | return; | |
fa7497e8 | 4830 | -- Otherwise install access check |
4831 | ||
4832 | else | |
4833 | Insert_Action (N, | |
4834 | Make_Raise_Constraint_Error (Loc, | |
4835 | Condition => | |
4836 | Make_Op_Eq (Loc, | |
4837 | Left_Opnd => Duplicate_Subexpr_Move_Checks (N), | |
4838 | Right_Opnd => Make_Null (Loc)), | |
4839 | Reason => CE_Access_Check_Failed)); | |
4840 | end if; | |
4841 | end Install_Null_Excluding_Check; | |
4842 | ||
ee6ba406 | 4843 | -------------------------- |
4844 | -- Install_Static_Check -- | |
4845 | -------------------------- | |
4846 | ||
4847 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is | |
4848 | Stat : constant Boolean := Is_Static_Expression (R_Cno); | |
4849 | Typ : constant Entity_Id := Etype (R_Cno); | |
4850 | ||
4851 | begin | |
f15731c4 | 4852 | Rewrite (R_Cno, |
4853 | Make_Raise_Constraint_Error (Loc, | |
4854 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 4855 | Set_Analyzed (R_Cno); |
4856 | Set_Etype (R_Cno, Typ); | |
4857 | Set_Raises_Constraint_Error (R_Cno); | |
4858 | Set_Is_Static_Expression (R_Cno, Stat); | |
4859 | end Install_Static_Check; | |
4860 | ||
9dfe12ae | 4861 | --------------------- |
4862 | -- Kill_All_Checks -- | |
4863 | --------------------- | |
4864 | ||
4865 | procedure Kill_All_Checks is | |
4866 | begin | |
4867 | if Debug_Flag_CC then | |
4868 | w ("Kill_All_Checks"); | |
4869 | end if; | |
4870 | ||
4871 | -- We reset the number of saved checks to zero, and also modify | |
4872 | -- all stack entries for statement ranges to indicate that the | |
4873 | -- number of checks at each level is now zero. | |
4874 | ||
4875 | Num_Saved_Checks := 0; | |
4876 | ||
4877 | for J in 1 .. Saved_Checks_TOS loop | |
4878 | Saved_Checks_Stack (J) := 0; | |
4879 | end loop; | |
4880 | end Kill_All_Checks; | |
4881 | ||
4882 | ----------------- | |
4883 | -- Kill_Checks -- | |
4884 | ----------------- | |
4885 | ||
4886 | procedure Kill_Checks (V : Entity_Id) is | |
4887 | begin | |
4888 | if Debug_Flag_CC then | |
4889 | w ("Kill_Checks for entity", Int (V)); | |
4890 | end if; | |
4891 | ||
4892 | for J in 1 .. Num_Saved_Checks loop | |
4893 | if Saved_Checks (J).Entity = V then | |
4894 | if Debug_Flag_CC then | |
4895 | w (" Checks killed for saved check ", J); | |
4896 | end if; | |
4897 | ||
4898 | Saved_Checks (J).Killed := True; | |
4899 | end if; | |
4900 | end loop; | |
4901 | end Kill_Checks; | |
4902 | ||
ee6ba406 | 4903 | ------------------------------ |
4904 | -- Length_Checks_Suppressed -- | |
4905 | ------------------------------ | |
4906 | ||
4907 | function Length_Checks_Suppressed (E : Entity_Id) return Boolean is | |
4908 | begin | |
9dfe12ae | 4909 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
4910 | return Is_Check_Suppressed (E, Length_Check); | |
4911 | else | |
4912 | return Scope_Suppress (Length_Check); | |
4913 | end if; | |
ee6ba406 | 4914 | end Length_Checks_Suppressed; |
4915 | ||
4916 | -------------------------------- | |
4917 | -- Overflow_Checks_Suppressed -- | |
4918 | -------------------------------- | |
4919 | ||
4920 | function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is | |
4921 | begin | |
9dfe12ae | 4922 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
4923 | return Is_Check_Suppressed (E, Overflow_Check); | |
4924 | else | |
4925 | return Scope_Suppress (Overflow_Check); | |
4926 | end if; | |
ee6ba406 | 4927 | end Overflow_Checks_Suppressed; |
4928 | ||
4929 | ----------------- | |
4930 | -- Range_Check -- | |
4931 | ----------------- | |
4932 | ||
4933 | function Range_Check | |
4934 | (Ck_Node : Node_Id; | |
4935 | Target_Typ : Entity_Id; | |
4936 | Source_Typ : Entity_Id := Empty; | |
314a23b6 | 4937 | Warn_Node : Node_Id := Empty) return Check_Result |
ee6ba406 | 4938 | is |
4939 | begin | |
4940 | return Selected_Range_Checks | |
4941 | (Ck_Node, Target_Typ, Source_Typ, Warn_Node); | |
4942 | end Range_Check; | |
4943 | ||
4944 | ----------------------------- | |
4945 | -- Range_Checks_Suppressed -- | |
4946 | ----------------------------- | |
4947 | ||
4948 | function Range_Checks_Suppressed (E : Entity_Id) return Boolean is | |
4949 | begin | |
9dfe12ae | 4950 | if Present (E) then |
4951 | ||
4952 | -- Note: for now we always suppress range checks on Vax float types, | |
4953 | -- since Gigi does not know how to generate these checks. | |
4954 | ||
4955 | if Vax_Float (E) then | |
4956 | return True; | |
4957 | elsif Kill_Range_Checks (E) then | |
4958 | return True; | |
4959 | elsif Checks_May_Be_Suppressed (E) then | |
4960 | return Is_Check_Suppressed (E, Range_Check); | |
4961 | end if; | |
4962 | end if; | |
ee6ba406 | 4963 | |
9dfe12ae | 4964 | return Scope_Suppress (Range_Check); |
ee6ba406 | 4965 | end Range_Checks_Suppressed; |
4966 | ||
226494a3 | 4967 | ------------------- |
4968 | -- Remove_Checks -- | |
4969 | ------------------- | |
4970 | ||
4971 | procedure Remove_Checks (Expr : Node_Id) is | |
4972 | Discard : Traverse_Result; | |
9dfe12ae | 4973 | pragma Warnings (Off, Discard); |
226494a3 | 4974 | |
4975 | function Process (N : Node_Id) return Traverse_Result; | |
4976 | -- Process a single node during the traversal | |
4977 | ||
4978 | function Traverse is new Traverse_Func (Process); | |
4979 | -- The traversal function itself | |
4980 | ||
4981 | ------------- | |
4982 | -- Process -- | |
4983 | ------------- | |
4984 | ||
4985 | function Process (N : Node_Id) return Traverse_Result is | |
4986 | begin | |
4987 | if Nkind (N) not in N_Subexpr then | |
4988 | return Skip; | |
4989 | end if; | |
4990 | ||
4991 | Set_Do_Range_Check (N, False); | |
4992 | ||
4993 | case Nkind (N) is | |
4994 | when N_And_Then => | |
4995 | Discard := Traverse (Left_Opnd (N)); | |
4996 | return Skip; | |
4997 | ||
4998 | when N_Attribute_Reference => | |
226494a3 | 4999 | Set_Do_Overflow_Check (N, False); |
5000 | ||
226494a3 | 5001 | when N_Function_Call => |
5002 | Set_Do_Tag_Check (N, False); | |
5003 | ||
226494a3 | 5004 | when N_Op => |
5005 | Set_Do_Overflow_Check (N, False); | |
5006 | ||
5007 | case Nkind (N) is | |
5008 | when N_Op_Divide => | |
5009 | Set_Do_Division_Check (N, False); | |
5010 | ||
5011 | when N_Op_And => | |
5012 | Set_Do_Length_Check (N, False); | |
5013 | ||
5014 | when N_Op_Mod => | |
5015 | Set_Do_Division_Check (N, False); | |
5016 | ||
5017 | when N_Op_Or => | |
5018 | Set_Do_Length_Check (N, False); | |
5019 | ||
5020 | when N_Op_Rem => | |
5021 | Set_Do_Division_Check (N, False); | |
5022 | ||
5023 | when N_Op_Xor => | |
5024 | Set_Do_Length_Check (N, False); | |
5025 | ||
5026 | when others => | |
5027 | null; | |
5028 | end case; | |
5029 | ||
5030 | when N_Or_Else => | |
5031 | Discard := Traverse (Left_Opnd (N)); | |
5032 | return Skip; | |
5033 | ||
5034 | when N_Selected_Component => | |
226494a3 | 5035 | Set_Do_Discriminant_Check (N, False); |
5036 | ||
226494a3 | 5037 | when N_Type_Conversion => |
9dfe12ae | 5038 | Set_Do_Length_Check (N, False); |
5039 | Set_Do_Tag_Check (N, False); | |
226494a3 | 5040 | Set_Do_Overflow_Check (N, False); |
226494a3 | 5041 | |
5042 | when others => | |
5043 | null; | |
5044 | end case; | |
5045 | ||
5046 | return OK; | |
5047 | end Process; | |
5048 | ||
5049 | -- Start of processing for Remove_Checks | |
5050 | ||
5051 | begin | |
5052 | Discard := Traverse (Expr); | |
5053 | end Remove_Checks; | |
5054 | ||
ee6ba406 | 5055 | ---------------------------- |
5056 | -- Selected_Length_Checks -- | |
5057 | ---------------------------- | |
5058 | ||
5059 | function Selected_Length_Checks | |
5060 | (Ck_Node : Node_Id; | |
5061 | Target_Typ : Entity_Id; | |
5062 | Source_Typ : Entity_Id; | |
314a23b6 | 5063 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 5064 | is |
5065 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
5066 | S_Typ : Entity_Id; | |
5067 | T_Typ : Entity_Id; | |
5068 | Expr_Actual : Node_Id; | |
5069 | Exptyp : Entity_Id; | |
5070 | Cond : Node_Id := Empty; | |
5071 | Do_Access : Boolean := False; | |
5072 | Wnode : Node_Id := Warn_Node; | |
5073 | Ret_Result : Check_Result := (Empty, Empty); | |
5074 | Num_Checks : Natural := 0; | |
5075 | ||
5076 | procedure Add_Check (N : Node_Id); | |
5077 | -- Adds the action given to Ret_Result if N is non-Empty | |
5078 | ||
5079 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id; | |
5080 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id; | |
314a23b6 | 5081 | -- Comments required ??? |
ee6ba406 | 5082 | |
5083 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean; | |
5084 | -- True for equal literals and for nodes that denote the same constant | |
5f260d20 | 5085 | -- entity, even if its value is not a static constant. This includes the |
9dfe12ae | 5086 | -- case of a discriminal reference within an init proc. Removes some |
5f260d20 | 5087 | -- obviously superfluous checks. |
ee6ba406 | 5088 | |
5089 | function Length_E_Cond | |
5090 | (Exptyp : Entity_Id; | |
5091 | Typ : Entity_Id; | |
314a23b6 | 5092 | Indx : Nat) return Node_Id; |
ee6ba406 | 5093 | -- Returns expression to compute: |
5094 | -- Typ'Length /= Exptyp'Length | |
5095 | ||
5096 | function Length_N_Cond | |
5097 | (Expr : Node_Id; | |
5098 | Typ : Entity_Id; | |
314a23b6 | 5099 | Indx : Nat) return Node_Id; |
ee6ba406 | 5100 | -- Returns expression to compute: |
5101 | -- Typ'Length /= Expr'Length | |
5102 | ||
5103 | --------------- | |
5104 | -- Add_Check -- | |
5105 | --------------- | |
5106 | ||
5107 | procedure Add_Check (N : Node_Id) is | |
5108 | begin | |
5109 | if Present (N) then | |
5110 | ||
5111 | -- For now, ignore attempt to place more than 2 checks ??? | |
5112 | ||
5113 | if Num_Checks = 2 then | |
5114 | return; | |
5115 | end if; | |
5116 | ||
5117 | pragma Assert (Num_Checks <= 1); | |
5118 | Num_Checks := Num_Checks + 1; | |
5119 | Ret_Result (Num_Checks) := N; | |
5120 | end if; | |
5121 | end Add_Check; | |
5122 | ||
5123 | ------------------ | |
5124 | -- Get_E_Length -- | |
5125 | ------------------ | |
5126 | ||
5127 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is | |
9dfe12ae | 5128 | Pt : constant Entity_Id := Scope (Scope (E)); |
ee6ba406 | 5129 | N : Node_Id; |
5130 | E1 : Entity_Id := E; | |
ee6ba406 | 5131 | |
5132 | begin | |
5133 | if Ekind (Scope (E)) = E_Record_Type | |
5134 | and then Has_Discriminants (Scope (E)) | |
5135 | then | |
5136 | N := Build_Discriminal_Subtype_Of_Component (E); | |
5137 | ||
5138 | if Present (N) then | |
5139 | Insert_Action (Ck_Node, N); | |
5140 | E1 := Defining_Identifier (N); | |
5141 | end if; | |
5142 | end if; | |
5143 | ||
5144 | if Ekind (E1) = E_String_Literal_Subtype then | |
5145 | return | |
5146 | Make_Integer_Literal (Loc, | |
5147 | Intval => String_Literal_Length (E1)); | |
5148 | ||
5149 | elsif Ekind (Pt) = E_Protected_Type | |
5150 | and then Has_Discriminants (Pt) | |
5151 | and then Has_Completion (Pt) | |
5152 | and then not Inside_Init_Proc | |
5153 | then | |
5154 | ||
5155 | -- If the type whose length is needed is a private component | |
5156 | -- constrained by a discriminant, we must expand the 'Length | |
5157 | -- attribute into an explicit computation, using the discriminal | |
5158 | -- of the current protected operation. This is because the actual | |
5159 | -- type of the prival is constructed after the protected opera- | |
5160 | -- tion has been fully expanded. | |
5161 | ||
5162 | declare | |
5163 | Indx_Type : Node_Id; | |
5164 | Lo : Node_Id; | |
5165 | Hi : Node_Id; | |
5166 | Do_Expand : Boolean := False; | |
5167 | ||
5168 | begin | |
5169 | Indx_Type := First_Index (E); | |
5170 | ||
5171 | for J in 1 .. Indx - 1 loop | |
5172 | Next_Index (Indx_Type); | |
5173 | end loop; | |
5174 | ||
5175 | Get_Index_Bounds (Indx_Type, Lo, Hi); | |
5176 | ||
5177 | if Nkind (Lo) = N_Identifier | |
5178 | and then Ekind (Entity (Lo)) = E_In_Parameter | |
5179 | then | |
5180 | Lo := Get_Discriminal (E, Lo); | |
5181 | Do_Expand := True; | |
5182 | end if; | |
5183 | ||
5184 | if Nkind (Hi) = N_Identifier | |
5185 | and then Ekind (Entity (Hi)) = E_In_Parameter | |
5186 | then | |
5187 | Hi := Get_Discriminal (E, Hi); | |
5188 | Do_Expand := True; | |
5189 | end if; | |
5190 | ||
5191 | if Do_Expand then | |
5192 | if not Is_Entity_Name (Lo) then | |
9dfe12ae | 5193 | Lo := Duplicate_Subexpr_No_Checks (Lo); |
ee6ba406 | 5194 | end if; |
5195 | ||
5196 | if not Is_Entity_Name (Hi) then | |
9dfe12ae | 5197 | Lo := Duplicate_Subexpr_No_Checks (Hi); |
ee6ba406 | 5198 | end if; |
5199 | ||
5200 | N := | |
5201 | Make_Op_Add (Loc, | |
5202 | Left_Opnd => | |
5203 | Make_Op_Subtract (Loc, | |
5204 | Left_Opnd => Hi, | |
5205 | Right_Opnd => Lo), | |
5206 | ||
5207 | Right_Opnd => Make_Integer_Literal (Loc, 1)); | |
5208 | return N; | |
5209 | ||
5210 | else | |
5211 | N := | |
5212 | Make_Attribute_Reference (Loc, | |
5213 | Attribute_Name => Name_Length, | |
5214 | Prefix => | |
5215 | New_Occurrence_Of (E1, Loc)); | |
5216 | ||
5217 | if Indx > 1 then | |
5218 | Set_Expressions (N, New_List ( | |
5219 | Make_Integer_Literal (Loc, Indx))); | |
5220 | end if; | |
5221 | ||
5222 | return N; | |
5223 | end if; | |
5224 | end; | |
5225 | ||
5226 | else | |
5227 | N := | |
5228 | Make_Attribute_Reference (Loc, | |
5229 | Attribute_Name => Name_Length, | |
5230 | Prefix => | |
5231 | New_Occurrence_Of (E1, Loc)); | |
5232 | ||
5233 | if Indx > 1 then | |
5234 | Set_Expressions (N, New_List ( | |
5235 | Make_Integer_Literal (Loc, Indx))); | |
5236 | end if; | |
5237 | ||
5238 | return N; | |
5239 | ||
5240 | end if; | |
5241 | end Get_E_Length; | |
5242 | ||
5243 | ------------------ | |
5244 | -- Get_N_Length -- | |
5245 | ------------------ | |
5246 | ||
5247 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is | |
5248 | begin | |
5249 | return | |
5250 | Make_Attribute_Reference (Loc, | |
5251 | Attribute_Name => Name_Length, | |
5252 | Prefix => | |
9dfe12ae | 5253 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 5254 | Expressions => New_List ( |
5255 | Make_Integer_Literal (Loc, Indx))); | |
5256 | ||
5257 | end Get_N_Length; | |
5258 | ||
5259 | ------------------- | |
5260 | -- Length_E_Cond -- | |
5261 | ------------------- | |
5262 | ||
5263 | function Length_E_Cond | |
5264 | (Exptyp : Entity_Id; | |
5265 | Typ : Entity_Id; | |
314a23b6 | 5266 | Indx : Nat) return Node_Id |
ee6ba406 | 5267 | is |
5268 | begin | |
5269 | return | |
5270 | Make_Op_Ne (Loc, | |
5271 | Left_Opnd => Get_E_Length (Typ, Indx), | |
5272 | Right_Opnd => Get_E_Length (Exptyp, Indx)); | |
5273 | ||
5274 | end Length_E_Cond; | |
5275 | ||
5276 | ------------------- | |
5277 | -- Length_N_Cond -- | |
5278 | ------------------- | |
5279 | ||
5280 | function Length_N_Cond | |
5281 | (Expr : Node_Id; | |
5282 | Typ : Entity_Id; | |
314a23b6 | 5283 | Indx : Nat) return Node_Id |
ee6ba406 | 5284 | is |
5285 | begin | |
5286 | return | |
5287 | Make_Op_Ne (Loc, | |
5288 | Left_Opnd => Get_E_Length (Typ, Indx), | |
5289 | Right_Opnd => Get_N_Length (Expr, Indx)); | |
5290 | ||
5291 | end Length_N_Cond; | |
5292 | ||
5293 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is | |
5294 | begin | |
5295 | return | |
5296 | (Nkind (L) = N_Integer_Literal | |
5297 | and then Nkind (R) = N_Integer_Literal | |
5298 | and then Intval (L) = Intval (R)) | |
5299 | ||
5300 | or else | |
5301 | (Is_Entity_Name (L) | |
5302 | and then Ekind (Entity (L)) = E_Constant | |
5303 | and then ((Is_Entity_Name (R) | |
5304 | and then Entity (L) = Entity (R)) | |
5305 | or else | |
5306 | (Nkind (R) = N_Type_Conversion | |
5307 | and then Is_Entity_Name (Expression (R)) | |
5308 | and then Entity (L) = Entity (Expression (R))))) | |
5309 | ||
5310 | or else | |
5311 | (Is_Entity_Name (R) | |
5312 | and then Ekind (Entity (R)) = E_Constant | |
5313 | and then Nkind (L) = N_Type_Conversion | |
5314 | and then Is_Entity_Name (Expression (L)) | |
5f260d20 | 5315 | and then Entity (R) = Entity (Expression (L))) |
5316 | ||
5317 | or else | |
5318 | (Is_Entity_Name (L) | |
5319 | and then Is_Entity_Name (R) | |
5320 | and then Entity (L) = Entity (R) | |
5321 | and then Ekind (Entity (L)) = E_In_Parameter | |
5322 | and then Inside_Init_Proc); | |
ee6ba406 | 5323 | end Same_Bounds; |
5324 | ||
5325 | -- Start of processing for Selected_Length_Checks | |
5326 | ||
5327 | begin | |
5328 | if not Expander_Active then | |
5329 | return Ret_Result; | |
5330 | end if; | |
5331 | ||
5332 | if Target_Typ = Any_Type | |
5333 | or else Target_Typ = Any_Composite | |
5334 | or else Raises_Constraint_Error (Ck_Node) | |
5335 | then | |
5336 | return Ret_Result; | |
5337 | end if; | |
5338 | ||
5339 | if No (Wnode) then | |
5340 | Wnode := Ck_Node; | |
5341 | end if; | |
5342 | ||
5343 | T_Typ := Target_Typ; | |
5344 | ||
5345 | if No (Source_Typ) then | |
5346 | S_Typ := Etype (Ck_Node); | |
5347 | else | |
5348 | S_Typ := Source_Typ; | |
5349 | end if; | |
5350 | ||
5351 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
5352 | return Ret_Result; | |
5353 | end if; | |
5354 | ||
5355 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
5356 | S_Typ := Designated_Type (S_Typ); | |
5357 | T_Typ := Designated_Type (T_Typ); | |
5358 | Do_Access := True; | |
5359 | ||
5360 | -- A simple optimization | |
5361 | ||
5362 | if Nkind (Ck_Node) = N_Null then | |
5363 | return Ret_Result; | |
5364 | end if; | |
5365 | end if; | |
5366 | ||
5367 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
5368 | if Is_Constrained (T_Typ) then | |
5369 | ||
5370 | -- The checking code to be generated will freeze the | |
5371 | -- corresponding array type. However, we must freeze the | |
5372 | -- type now, so that the freeze node does not appear within | |
5373 | -- the generated condional expression, but ahead of it. | |
5374 | ||
5375 | Freeze_Before (Ck_Node, T_Typ); | |
5376 | ||
5377 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
5378 | Exptyp := Get_Actual_Subtype (Expr_Actual); | |
5379 | ||
5380 | if Is_Access_Type (Exptyp) then | |
5381 | Exptyp := Designated_Type (Exptyp); | |
5382 | end if; | |
5383 | ||
5384 | -- String_Literal case. This needs to be handled specially be- | |
5385 | -- cause no index types are available for string literals. The | |
5386 | -- condition is simply: | |
5387 | ||
5388 | -- T_Typ'Length = string-literal-length | |
5389 | ||
9dfe12ae | 5390 | if Nkind (Expr_Actual) = N_String_Literal |
5391 | and then Ekind (Etype (Expr_Actual)) = E_String_Literal_Subtype | |
5392 | then | |
ee6ba406 | 5393 | Cond := |
5394 | Make_Op_Ne (Loc, | |
5395 | Left_Opnd => Get_E_Length (T_Typ, 1), | |
5396 | Right_Opnd => | |
5397 | Make_Integer_Literal (Loc, | |
5398 | Intval => | |
5399 | String_Literal_Length (Etype (Expr_Actual)))); | |
5400 | ||
5401 | -- General array case. Here we have a usable actual subtype for | |
5402 | -- the expression, and the condition is built from the two types | |
5403 | -- (Do_Length): | |
5404 | ||
5405 | -- T_Typ'Length /= Exptyp'Length or else | |
5406 | -- T_Typ'Length (2) /= Exptyp'Length (2) or else | |
5407 | -- T_Typ'Length (3) /= Exptyp'Length (3) or else | |
5408 | -- ... | |
5409 | ||
5410 | elsif Is_Constrained (Exptyp) then | |
5411 | declare | |
9dfe12ae | 5412 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
5413 | ||
5414 | L_Index : Node_Id; | |
5415 | R_Index : Node_Id; | |
5416 | L_Low : Node_Id; | |
5417 | L_High : Node_Id; | |
5418 | R_Low : Node_Id; | |
5419 | R_High : Node_Id; | |
ee6ba406 | 5420 | L_Length : Uint; |
5421 | R_Length : Uint; | |
9dfe12ae | 5422 | Ref_Node : Node_Id; |
ee6ba406 | 5423 | |
5424 | begin | |
9dfe12ae | 5425 | |
5426 | -- At the library level, we need to ensure that the | |
5427 | -- type of the object is elaborated before the check | |
d66aa9f6 | 5428 | -- itself is emitted. This is only done if the object |
5429 | -- is in the current compilation unit, otherwise the | |
5430 | -- type is frozen and elaborated in its unit. | |
9dfe12ae | 5431 | |
5432 | if Is_Itype (Exptyp) | |
5433 | and then | |
5434 | Ekind (Cunit_Entity (Current_Sem_Unit)) = E_Package | |
5435 | and then | |
5436 | not In_Package_Body (Cunit_Entity (Current_Sem_Unit)) | |
d66aa9f6 | 5437 | and then In_Open_Scopes (Scope (Exptyp)) |
9dfe12ae | 5438 | then |
5439 | Ref_Node := Make_Itype_Reference (Sloc (Ck_Node)); | |
5440 | Set_Itype (Ref_Node, Exptyp); | |
5441 | Insert_Action (Ck_Node, Ref_Node); | |
5442 | end if; | |
5443 | ||
ee6ba406 | 5444 | L_Index := First_Index (T_Typ); |
5445 | R_Index := First_Index (Exptyp); | |
5446 | ||
5447 | for Indx in 1 .. Ndims loop | |
5448 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 5449 | or else |
5450 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 5451 | then |
5452 | Get_Index_Bounds (L_Index, L_Low, L_High); | |
5453 | Get_Index_Bounds (R_Index, R_Low, R_High); | |
5454 | ||
5455 | -- Deal with compile time length check. Note that we | |
5456 | -- skip this in the access case, because the access | |
5457 | -- value may be null, so we cannot know statically. | |
5458 | ||
5459 | if not Do_Access | |
5460 | and then Compile_Time_Known_Value (L_Low) | |
5461 | and then Compile_Time_Known_Value (L_High) | |
5462 | and then Compile_Time_Known_Value (R_Low) | |
5463 | and then Compile_Time_Known_Value (R_High) | |
5464 | then | |
5465 | if Expr_Value (L_High) >= Expr_Value (L_Low) then | |
5466 | L_Length := Expr_Value (L_High) - | |
5467 | Expr_Value (L_Low) + 1; | |
5468 | else | |
5469 | L_Length := UI_From_Int (0); | |
5470 | end if; | |
5471 | ||
5472 | if Expr_Value (R_High) >= Expr_Value (R_Low) then | |
5473 | R_Length := Expr_Value (R_High) - | |
5474 | Expr_Value (R_Low) + 1; | |
5475 | else | |
5476 | R_Length := UI_From_Int (0); | |
5477 | end if; | |
5478 | ||
5479 | if L_Length > R_Length then | |
5480 | Add_Check | |
5481 | (Compile_Time_Constraint_Error | |
5482 | (Wnode, "too few elements for}?", T_Typ)); | |
5483 | ||
5484 | elsif L_Length < R_Length then | |
5485 | Add_Check | |
5486 | (Compile_Time_Constraint_Error | |
5487 | (Wnode, "too many elements for}?", T_Typ)); | |
5488 | end if; | |
5489 | ||
5490 | -- The comparison for an individual index subtype | |
5491 | -- is omitted if the corresponding index subtypes | |
5492 | -- statically match, since the result is known to | |
5493 | -- be true. Note that this test is worth while even | |
5494 | -- though we do static evaluation, because non-static | |
5495 | -- subtypes can statically match. | |
5496 | ||
5497 | elsif not | |
5498 | Subtypes_Statically_Match | |
5499 | (Etype (L_Index), Etype (R_Index)) | |
5500 | ||
5501 | and then not | |
5502 | (Same_Bounds (L_Low, R_Low) | |
5503 | and then Same_Bounds (L_High, R_High)) | |
5504 | then | |
5505 | Evolve_Or_Else | |
5506 | (Cond, Length_E_Cond (Exptyp, T_Typ, Indx)); | |
5507 | end if; | |
5508 | ||
5509 | Next (L_Index); | |
5510 | Next (R_Index); | |
5511 | end if; | |
5512 | end loop; | |
5513 | end; | |
5514 | ||
5515 | -- Handle cases where we do not get a usable actual subtype that | |
5516 | -- is constrained. This happens for example in the function call | |
5517 | -- and explicit dereference cases. In these cases, we have to get | |
5518 | -- the length or range from the expression itself, making sure we | |
5519 | -- do not evaluate it more than once. | |
5520 | ||
5521 | -- Here Ck_Node is the original expression, or more properly the | |
5522 | -- result of applying Duplicate_Expr to the original tree, | |
5523 | -- forcing the result to be a name. | |
5524 | ||
5525 | else | |
5526 | declare | |
9dfe12ae | 5527 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 5528 | |
5529 | begin | |
5530 | -- Build the condition for the explicit dereference case | |
5531 | ||
5532 | for Indx in 1 .. Ndims loop | |
5533 | Evolve_Or_Else | |
5534 | (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx)); | |
5535 | end loop; | |
5536 | end; | |
5537 | end if; | |
5538 | end if; | |
5539 | end if; | |
5540 | ||
5541 | -- Construct the test and insert into the tree | |
5542 | ||
5543 | if Present (Cond) then | |
5544 | if Do_Access then | |
5545 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
5546 | end if; | |
5547 | ||
f15731c4 | 5548 | Add_Check |
5549 | (Make_Raise_Constraint_Error (Loc, | |
5550 | Condition => Cond, | |
5551 | Reason => CE_Length_Check_Failed)); | |
ee6ba406 | 5552 | end if; |
5553 | ||
5554 | return Ret_Result; | |
ee6ba406 | 5555 | end Selected_Length_Checks; |
5556 | ||
5557 | --------------------------- | |
5558 | -- Selected_Range_Checks -- | |
5559 | --------------------------- | |
5560 | ||
5561 | function Selected_Range_Checks | |
5562 | (Ck_Node : Node_Id; | |
5563 | Target_Typ : Entity_Id; | |
5564 | Source_Typ : Entity_Id; | |
314a23b6 | 5565 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 5566 | is |
5567 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
5568 | S_Typ : Entity_Id; | |
5569 | T_Typ : Entity_Id; | |
5570 | Expr_Actual : Node_Id; | |
5571 | Exptyp : Entity_Id; | |
5572 | Cond : Node_Id := Empty; | |
5573 | Do_Access : Boolean := False; | |
5574 | Wnode : Node_Id := Warn_Node; | |
5575 | Ret_Result : Check_Result := (Empty, Empty); | |
5576 | Num_Checks : Integer := 0; | |
5577 | ||
5578 | procedure Add_Check (N : Node_Id); | |
5579 | -- Adds the action given to Ret_Result if N is non-Empty | |
5580 | ||
5581 | function Discrete_Range_Cond | |
5582 | (Expr : Node_Id; | |
314a23b6 | 5583 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 5584 | -- Returns expression to compute: |
5585 | -- Low_Bound (Expr) < Typ'First | |
5586 | -- or else | |
5587 | -- High_Bound (Expr) > Typ'Last | |
5588 | ||
5589 | function Discrete_Expr_Cond | |
5590 | (Expr : Node_Id; | |
314a23b6 | 5591 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 5592 | -- Returns expression to compute: |
5593 | -- Expr < Typ'First | |
5594 | -- or else | |
5595 | -- Expr > Typ'Last | |
5596 | ||
5597 | function Get_E_First_Or_Last | |
5598 | (E : Entity_Id; | |
5599 | Indx : Nat; | |
314a23b6 | 5600 | Nam : Name_Id) return Node_Id; |
ee6ba406 | 5601 | -- Returns expression to compute: |
5602 | -- E'First or E'Last | |
5603 | ||
5604 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id; | |
5605 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id; | |
5606 | -- Returns expression to compute: | |
9dfe12ae | 5607 | -- N'First or N'Last using Duplicate_Subexpr_No_Checks |
ee6ba406 | 5608 | |
5609 | function Range_E_Cond | |
5610 | (Exptyp : Entity_Id; | |
5611 | Typ : Entity_Id; | |
5612 | Indx : Nat) | |
5613 | return Node_Id; | |
5614 | -- Returns expression to compute: | |
5615 | -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last | |
5616 | ||
5617 | function Range_Equal_E_Cond | |
5618 | (Exptyp : Entity_Id; | |
5619 | Typ : Entity_Id; | |
314a23b6 | 5620 | Indx : Nat) return Node_Id; |
ee6ba406 | 5621 | -- Returns expression to compute: |
5622 | -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last | |
5623 | ||
5624 | function Range_N_Cond | |
5625 | (Expr : Node_Id; | |
5626 | Typ : Entity_Id; | |
314a23b6 | 5627 | Indx : Nat) return Node_Id; |
ee6ba406 | 5628 | -- Return expression to compute: |
5629 | -- Expr'First < Typ'First or else Expr'Last > Typ'Last | |
5630 | ||
5631 | --------------- | |
5632 | -- Add_Check -- | |
5633 | --------------- | |
5634 | ||
5635 | procedure Add_Check (N : Node_Id) is | |
5636 | begin | |
5637 | if Present (N) then | |
5638 | ||
5639 | -- For now, ignore attempt to place more than 2 checks ??? | |
5640 | ||
5641 | if Num_Checks = 2 then | |
5642 | return; | |
5643 | end if; | |
5644 | ||
5645 | pragma Assert (Num_Checks <= 1); | |
5646 | Num_Checks := Num_Checks + 1; | |
5647 | Ret_Result (Num_Checks) := N; | |
5648 | end if; | |
5649 | end Add_Check; | |
5650 | ||
5651 | ------------------------- | |
5652 | -- Discrete_Expr_Cond -- | |
5653 | ------------------------- | |
5654 | ||
5655 | function Discrete_Expr_Cond | |
5656 | (Expr : Node_Id; | |
314a23b6 | 5657 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 5658 | is |
5659 | begin | |
5660 | return | |
5661 | Make_Or_Else (Loc, | |
5662 | Left_Opnd => | |
5663 | Make_Op_Lt (Loc, | |
5664 | Left_Opnd => | |
9dfe12ae | 5665 | Convert_To (Base_Type (Typ), |
5666 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 5667 | Right_Opnd => |
5668 | Convert_To (Base_Type (Typ), | |
5669 | Get_E_First_Or_Last (Typ, 0, Name_First))), | |
5670 | ||
5671 | Right_Opnd => | |
5672 | Make_Op_Gt (Loc, | |
5673 | Left_Opnd => | |
9dfe12ae | 5674 | Convert_To (Base_Type (Typ), |
5675 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 5676 | Right_Opnd => |
5677 | Convert_To | |
5678 | (Base_Type (Typ), | |
5679 | Get_E_First_Or_Last (Typ, 0, Name_Last)))); | |
5680 | end Discrete_Expr_Cond; | |
5681 | ||
5682 | ------------------------- | |
5683 | -- Discrete_Range_Cond -- | |
5684 | ------------------------- | |
5685 | ||
5686 | function Discrete_Range_Cond | |
5687 | (Expr : Node_Id; | |
314a23b6 | 5688 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 5689 | is |
5690 | LB : Node_Id := Low_Bound (Expr); | |
5691 | HB : Node_Id := High_Bound (Expr); | |
5692 | ||
5693 | Left_Opnd : Node_Id; | |
5694 | Right_Opnd : Node_Id; | |
5695 | ||
5696 | begin | |
5697 | if Nkind (LB) = N_Identifier | |
5698 | and then Ekind (Entity (LB)) = E_Discriminant then | |
5699 | LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc); | |
5700 | end if; | |
5701 | ||
5702 | if Nkind (HB) = N_Identifier | |
5703 | and then Ekind (Entity (HB)) = E_Discriminant then | |
5704 | HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc); | |
5705 | end if; | |
5706 | ||
5707 | Left_Opnd := | |
5708 | Make_Op_Lt (Loc, | |
5709 | Left_Opnd => | |
5710 | Convert_To | |
9dfe12ae | 5711 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (LB)), |
ee6ba406 | 5712 | |
5713 | Right_Opnd => | |
5714 | Convert_To | |
5715 | (Base_Type (Typ), Get_E_First_Or_Last (Typ, 0, Name_First))); | |
5716 | ||
5717 | if Base_Type (Typ) = Typ then | |
5718 | return Left_Opnd; | |
5719 | ||
5720 | elsif Compile_Time_Known_Value (High_Bound (Scalar_Range (Typ))) | |
5721 | and then | |
5722 | Compile_Time_Known_Value (High_Bound (Scalar_Range | |
5723 | (Base_Type (Typ)))) | |
5724 | then | |
5725 | if Is_Floating_Point_Type (Typ) then | |
5726 | if Expr_Value_R (High_Bound (Scalar_Range (Typ))) = | |
5727 | Expr_Value_R (High_Bound (Scalar_Range (Base_Type (Typ)))) | |
5728 | then | |
5729 | return Left_Opnd; | |
5730 | end if; | |
5731 | ||
5732 | else | |
5733 | if Expr_Value (High_Bound (Scalar_Range (Typ))) = | |
5734 | Expr_Value (High_Bound (Scalar_Range (Base_Type (Typ)))) | |
5735 | then | |
5736 | return Left_Opnd; | |
5737 | end if; | |
5738 | end if; | |
5739 | end if; | |
5740 | ||
5741 | Right_Opnd := | |
5742 | Make_Op_Gt (Loc, | |
5743 | Left_Opnd => | |
5744 | Convert_To | |
9dfe12ae | 5745 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (HB)), |
ee6ba406 | 5746 | |
5747 | Right_Opnd => | |
5748 | Convert_To | |
5749 | (Base_Type (Typ), | |
5750 | Get_E_First_Or_Last (Typ, 0, Name_Last))); | |
5751 | ||
5752 | return Make_Or_Else (Loc, Left_Opnd, Right_Opnd); | |
5753 | end Discrete_Range_Cond; | |
5754 | ||
5755 | ------------------------- | |
5756 | -- Get_E_First_Or_Last -- | |
5757 | ------------------------- | |
5758 | ||
5759 | function Get_E_First_Or_Last | |
5760 | (E : Entity_Id; | |
5761 | Indx : Nat; | |
314a23b6 | 5762 | Nam : Name_Id) return Node_Id |
ee6ba406 | 5763 | is |
5764 | N : Node_Id; | |
5765 | LB : Node_Id; | |
5766 | HB : Node_Id; | |
5767 | Bound : Node_Id; | |
5768 | ||
5769 | begin | |
5770 | if Is_Array_Type (E) then | |
5771 | N := First_Index (E); | |
5772 | ||
5773 | for J in 2 .. Indx loop | |
5774 | Next_Index (N); | |
5775 | end loop; | |
5776 | ||
5777 | else | |
5778 | N := Scalar_Range (E); | |
5779 | end if; | |
5780 | ||
5781 | if Nkind (N) = N_Subtype_Indication then | |
5782 | LB := Low_Bound (Range_Expression (Constraint (N))); | |
5783 | HB := High_Bound (Range_Expression (Constraint (N))); | |
5784 | ||
5785 | elsif Is_Entity_Name (N) then | |
5786 | LB := Type_Low_Bound (Etype (N)); | |
5787 | HB := Type_High_Bound (Etype (N)); | |
5788 | ||
5789 | else | |
5790 | LB := Low_Bound (N); | |
5791 | HB := High_Bound (N); | |
5792 | end if; | |
5793 | ||
5794 | if Nam = Name_First then | |
5795 | Bound := LB; | |
5796 | else | |
5797 | Bound := HB; | |
5798 | end if; | |
5799 | ||
5800 | if Nkind (Bound) = N_Identifier | |
5801 | and then Ekind (Entity (Bound)) = E_Discriminant | |
5802 | then | |
9dfe12ae | 5803 | -- If this is a task discriminant, and we are the body, we must |
5804 | -- retrieve the corresponding body discriminal. This is another | |
5805 | -- consequence of the early creation of discriminals, and the | |
5806 | -- need to generate constraint checks before their declarations | |
5807 | -- are made visible. | |
5808 | ||
5809 | if Is_Concurrent_Record_Type (Scope (Entity (Bound))) then | |
5810 | declare | |
5811 | Tsk : constant Entity_Id := | |
5812 | Corresponding_Concurrent_Type | |
5813 | (Scope (Entity (Bound))); | |
5814 | Disc : Entity_Id; | |
5815 | ||
5816 | begin | |
5817 | if In_Open_Scopes (Tsk) | |
5818 | and then Has_Completion (Tsk) | |
5819 | then | |
5820 | -- Find discriminant of original task, and use its | |
5821 | -- current discriminal, which is the renaming within | |
5822 | -- the task body. | |
5823 | ||
5824 | Disc := First_Discriminant (Tsk); | |
5825 | while Present (Disc) loop | |
5826 | if Chars (Disc) = Chars (Entity (Bound)) then | |
5827 | Set_Scope (Discriminal (Disc), Tsk); | |
5828 | return New_Occurrence_Of (Discriminal (Disc), Loc); | |
5829 | end if; | |
5830 | ||
5831 | Next_Discriminant (Disc); | |
5832 | end loop; | |
5833 | ||
5834 | -- That loop should always succeed in finding a matching | |
5835 | -- entry and returning. Fatal error if not. | |
5836 | ||
5837 | raise Program_Error; | |
5838 | ||
5839 | else | |
5840 | return | |
5841 | New_Occurrence_Of (Discriminal (Entity (Bound)), Loc); | |
5842 | end if; | |
5843 | end; | |
5844 | else | |
5845 | return New_Occurrence_Of (Discriminal (Entity (Bound)), Loc); | |
5846 | end if; | |
ee6ba406 | 5847 | |
5848 | elsif Nkind (Bound) = N_Identifier | |
5849 | and then Ekind (Entity (Bound)) = E_In_Parameter | |
5850 | and then not Inside_Init_Proc | |
5851 | then | |
5852 | return Get_Discriminal (E, Bound); | |
5853 | ||
5854 | elsif Nkind (Bound) = N_Integer_Literal then | |
18563cef | 5855 | return Make_Integer_Literal (Loc, Intval (Bound)); |
5856 | ||
5857 | -- Case of a bound that has been rewritten to an | |
5858 | -- N_Raise_Constraint_Error node because it is an out-of-range | |
5859 | -- value. We may not call Duplicate_Subexpr on this node because | |
5860 | -- an N_Raise_Constraint_Error is not side effect free, and we may | |
5861 | -- not assume that we are in the proper context to remove side | |
5862 | -- effects on it at the point of reference. | |
5863 | ||
5864 | elsif Nkind (Bound) = N_Raise_Constraint_Error then | |
5865 | return New_Copy_Tree (Bound); | |
ee6ba406 | 5866 | |
5867 | else | |
9dfe12ae | 5868 | return Duplicate_Subexpr_No_Checks (Bound); |
ee6ba406 | 5869 | end if; |
5870 | end Get_E_First_Or_Last; | |
5871 | ||
5872 | ----------------- | |
5873 | -- Get_N_First -- | |
5874 | ----------------- | |
5875 | ||
5876 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is | |
5877 | begin | |
5878 | return | |
5879 | Make_Attribute_Reference (Loc, | |
5880 | Attribute_Name => Name_First, | |
5881 | Prefix => | |
9dfe12ae | 5882 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 5883 | Expressions => New_List ( |
5884 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 5885 | end Get_N_First; |
5886 | ||
5887 | ---------------- | |
5888 | -- Get_N_Last -- | |
5889 | ---------------- | |
5890 | ||
5891 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is | |
5892 | begin | |
5893 | return | |
5894 | Make_Attribute_Reference (Loc, | |
5895 | Attribute_Name => Name_Last, | |
5896 | Prefix => | |
9dfe12ae | 5897 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 5898 | Expressions => New_List ( |
5899 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 5900 | end Get_N_Last; |
5901 | ||
5902 | ------------------ | |
5903 | -- Range_E_Cond -- | |
5904 | ------------------ | |
5905 | ||
5906 | function Range_E_Cond | |
5907 | (Exptyp : Entity_Id; | |
5908 | Typ : Entity_Id; | |
314a23b6 | 5909 | Indx : Nat) return Node_Id |
ee6ba406 | 5910 | is |
5911 | begin | |
5912 | return | |
5913 | Make_Or_Else (Loc, | |
5914 | Left_Opnd => | |
5915 | Make_Op_Lt (Loc, | |
5916 | Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_First), | |
5917 | Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)), | |
5918 | ||
5919 | Right_Opnd => | |
5920 | Make_Op_Gt (Loc, | |
5921 | Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_Last), | |
5922 | Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last))); | |
5923 | ||
5924 | end Range_E_Cond; | |
5925 | ||
5926 | ------------------------ | |
5927 | -- Range_Equal_E_Cond -- | |
5928 | ------------------------ | |
5929 | ||
5930 | function Range_Equal_E_Cond | |
5931 | (Exptyp : Entity_Id; | |
5932 | Typ : Entity_Id; | |
314a23b6 | 5933 | Indx : Nat) return Node_Id |
ee6ba406 | 5934 | is |
5935 | begin | |
5936 | return | |
5937 | Make_Or_Else (Loc, | |
5938 | Left_Opnd => | |
5939 | Make_Op_Ne (Loc, | |
5940 | Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_First), | |
5941 | Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)), | |
5942 | Right_Opnd => | |
5943 | Make_Op_Ne (Loc, | |
5944 | Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_Last), | |
5945 | Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last))); | |
5946 | end Range_Equal_E_Cond; | |
5947 | ||
5948 | ------------------ | |
5949 | -- Range_N_Cond -- | |
5950 | ------------------ | |
5951 | ||
5952 | function Range_N_Cond | |
5953 | (Expr : Node_Id; | |
5954 | Typ : Entity_Id; | |
314a23b6 | 5955 | Indx : Nat) return Node_Id |
ee6ba406 | 5956 | is |
5957 | begin | |
5958 | return | |
5959 | Make_Or_Else (Loc, | |
5960 | Left_Opnd => | |
5961 | Make_Op_Lt (Loc, | |
5962 | Left_Opnd => Get_N_First (Expr, Indx), | |
5963 | Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)), | |
5964 | ||
5965 | Right_Opnd => | |
5966 | Make_Op_Gt (Loc, | |
5967 | Left_Opnd => Get_N_Last (Expr, Indx), | |
5968 | Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last))); | |
5969 | end Range_N_Cond; | |
5970 | ||
5971 | -- Start of processing for Selected_Range_Checks | |
5972 | ||
5973 | begin | |
5974 | if not Expander_Active then | |
5975 | return Ret_Result; | |
5976 | end if; | |
5977 | ||
5978 | if Target_Typ = Any_Type | |
5979 | or else Target_Typ = Any_Composite | |
5980 | or else Raises_Constraint_Error (Ck_Node) | |
5981 | then | |
5982 | return Ret_Result; | |
5983 | end if; | |
5984 | ||
5985 | if No (Wnode) then | |
5986 | Wnode := Ck_Node; | |
5987 | end if; | |
5988 | ||
5989 | T_Typ := Target_Typ; | |
5990 | ||
5991 | if No (Source_Typ) then | |
5992 | S_Typ := Etype (Ck_Node); | |
5993 | else | |
5994 | S_Typ := Source_Typ; | |
5995 | end if; | |
5996 | ||
5997 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
5998 | return Ret_Result; | |
5999 | end if; | |
6000 | ||
6001 | -- The order of evaluating T_Typ before S_Typ seems to be critical | |
6002 | -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed | |
6003 | -- in, and since Node can be an N_Range node, it might be invalid. | |
6004 | -- Should there be an assert check somewhere for taking the Etype of | |
6005 | -- an N_Range node ??? | |
6006 | ||
6007 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
6008 | S_Typ := Designated_Type (S_Typ); | |
6009 | T_Typ := Designated_Type (T_Typ); | |
6010 | Do_Access := True; | |
6011 | ||
6012 | -- A simple optimization | |
6013 | ||
6014 | if Nkind (Ck_Node) = N_Null then | |
6015 | return Ret_Result; | |
6016 | end if; | |
6017 | end if; | |
6018 | ||
6019 | -- For an N_Range Node, check for a null range and then if not | |
6020 | -- null generate a range check action. | |
6021 | ||
6022 | if Nkind (Ck_Node) = N_Range then | |
6023 | ||
6024 | -- There's no point in checking a range against itself | |
6025 | ||
6026 | if Ck_Node = Scalar_Range (T_Typ) then | |
6027 | return Ret_Result; | |
6028 | end if; | |
6029 | ||
6030 | declare | |
6031 | T_LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
6032 | T_HB : constant Node_Id := Type_High_Bound (T_Typ); | |
6033 | LB : constant Node_Id := Low_Bound (Ck_Node); | |
6034 | HB : constant Node_Id := High_Bound (Ck_Node); | |
6035 | Null_Range : Boolean; | |
6036 | ||
6037 | Out_Of_Range_L : Boolean; | |
6038 | Out_Of_Range_H : Boolean; | |
6039 | ||
6040 | begin | |
6041 | -- Check for case where everything is static and we can | |
6042 | -- do the check at compile time. This is skipped if we | |
6043 | -- have an access type, since the access value may be null. | |
6044 | ||
6045 | -- ??? This code can be improved since you only need to know | |
6046 | -- that the two respective bounds (LB & T_LB or HB & T_HB) | |
6047 | -- are known at compile time to emit pertinent messages. | |
6048 | ||
6049 | if Compile_Time_Known_Value (LB) | |
6050 | and then Compile_Time_Known_Value (HB) | |
6051 | and then Compile_Time_Known_Value (T_LB) | |
6052 | and then Compile_Time_Known_Value (T_HB) | |
6053 | and then not Do_Access | |
6054 | then | |
6055 | -- Floating-point case | |
6056 | ||
6057 | if Is_Floating_Point_Type (S_Typ) then | |
6058 | Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB); | |
6059 | Out_Of_Range_L := | |
6060 | (Expr_Value_R (LB) < Expr_Value_R (T_LB)) | |
6061 | or else | |
6062 | (Expr_Value_R (LB) > Expr_Value_R (T_HB)); | |
6063 | ||
6064 | Out_Of_Range_H := | |
6065 | (Expr_Value_R (HB) > Expr_Value_R (T_HB)) | |
6066 | or else | |
6067 | (Expr_Value_R (HB) < Expr_Value_R (T_LB)); | |
6068 | ||
6069 | -- Fixed or discrete type case | |
6070 | ||
6071 | else | |
6072 | Null_Range := Expr_Value (HB) < Expr_Value (LB); | |
6073 | Out_Of_Range_L := | |
6074 | (Expr_Value (LB) < Expr_Value (T_LB)) | |
6075 | or else | |
6076 | (Expr_Value (LB) > Expr_Value (T_HB)); | |
6077 | ||
6078 | Out_Of_Range_H := | |
6079 | (Expr_Value (HB) > Expr_Value (T_HB)) | |
6080 | or else | |
6081 | (Expr_Value (HB) < Expr_Value (T_LB)); | |
6082 | end if; | |
6083 | ||
6084 | if not Null_Range then | |
6085 | if Out_Of_Range_L then | |
6086 | if No (Warn_Node) then | |
6087 | Add_Check | |
6088 | (Compile_Time_Constraint_Error | |
6089 | (Low_Bound (Ck_Node), | |
6090 | "static value out of range of}?", T_Typ)); | |
6091 | ||
6092 | else | |
6093 | Add_Check | |
6094 | (Compile_Time_Constraint_Error | |
6095 | (Wnode, | |
6096 | "static range out of bounds of}?", T_Typ)); | |
6097 | end if; | |
6098 | end if; | |
6099 | ||
6100 | if Out_Of_Range_H then | |
6101 | if No (Warn_Node) then | |
6102 | Add_Check | |
6103 | (Compile_Time_Constraint_Error | |
6104 | (High_Bound (Ck_Node), | |
6105 | "static value out of range of}?", T_Typ)); | |
6106 | ||
6107 | else | |
6108 | Add_Check | |
6109 | (Compile_Time_Constraint_Error | |
6110 | (Wnode, | |
6111 | "static range out of bounds of}?", T_Typ)); | |
6112 | end if; | |
6113 | end if; | |
6114 | ||
6115 | end if; | |
6116 | ||
6117 | else | |
6118 | declare | |
6119 | LB : Node_Id := Low_Bound (Ck_Node); | |
6120 | HB : Node_Id := High_Bound (Ck_Node); | |
6121 | ||
6122 | begin | |
6123 | ||
6124 | -- If either bound is a discriminant and we are within | |
6125 | -- the record declaration, it is a use of the discriminant | |
6126 | -- in a constraint of a component, and nothing can be | |
6127 | -- checked here. The check will be emitted within the | |
9dfe12ae | 6128 | -- init proc. Before then, the discriminal has no real |
ee6ba406 | 6129 | -- meaning. |
6130 | ||
6131 | if Nkind (LB) = N_Identifier | |
6132 | and then Ekind (Entity (LB)) = E_Discriminant | |
6133 | then | |
6134 | if Current_Scope = Scope (Entity (LB)) then | |
6135 | return Ret_Result; | |
6136 | else | |
6137 | LB := | |
6138 | New_Occurrence_Of (Discriminal (Entity (LB)), Loc); | |
6139 | end if; | |
6140 | end if; | |
6141 | ||
6142 | if Nkind (HB) = N_Identifier | |
6143 | and then Ekind (Entity (HB)) = E_Discriminant | |
6144 | then | |
6145 | if Current_Scope = Scope (Entity (HB)) then | |
6146 | return Ret_Result; | |
6147 | else | |
6148 | HB := | |
6149 | New_Occurrence_Of (Discriminal (Entity (HB)), Loc); | |
6150 | end if; | |
6151 | end if; | |
6152 | ||
6153 | Cond := Discrete_Range_Cond (Ck_Node, T_Typ); | |
6154 | Set_Paren_Count (Cond, 1); | |
6155 | ||
6156 | Cond := | |
6157 | Make_And_Then (Loc, | |
6158 | Left_Opnd => | |
6159 | Make_Op_Ge (Loc, | |
9dfe12ae | 6160 | Left_Opnd => Duplicate_Subexpr_No_Checks (HB), |
6161 | Right_Opnd => Duplicate_Subexpr_No_Checks (LB)), | |
ee6ba406 | 6162 | Right_Opnd => Cond); |
6163 | end; | |
6164 | ||
6165 | end if; | |
6166 | end; | |
6167 | ||
6168 | elsif Is_Scalar_Type (S_Typ) then | |
6169 | ||
6170 | -- This somewhat duplicates what Apply_Scalar_Range_Check does, | |
6171 | -- except the above simply sets a flag in the node and lets | |
6172 | -- gigi generate the check base on the Etype of the expression. | |
6173 | -- Sometimes, however we want to do a dynamic check against an | |
6174 | -- arbitrary target type, so we do that here. | |
6175 | ||
6176 | if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then | |
6177 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
6178 | ||
6179 | -- For literals, we can tell if the constraint error will be | |
6180 | -- raised at compile time, so we never need a dynamic check, but | |
6181 | -- if the exception will be raised, then post the usual warning, | |
6182 | -- and replace the literal with a raise constraint error | |
6183 | -- expression. As usual, skip this for access types | |
6184 | ||
6185 | elsif Compile_Time_Known_Value (Ck_Node) | |
6186 | and then not Do_Access | |
6187 | then | |
6188 | declare | |
6189 | LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
6190 | UB : constant Node_Id := Type_High_Bound (T_Typ); | |
6191 | ||
6192 | Out_Of_Range : Boolean; | |
6193 | Static_Bounds : constant Boolean := | |
6194 | Compile_Time_Known_Value (LB) | |
6195 | and Compile_Time_Known_Value (UB); | |
6196 | ||
6197 | begin | |
6198 | -- Following range tests should use Sem_Eval routine ??? | |
6199 | ||
6200 | if Static_Bounds then | |
6201 | if Is_Floating_Point_Type (S_Typ) then | |
6202 | Out_Of_Range := | |
6203 | (Expr_Value_R (Ck_Node) < Expr_Value_R (LB)) | |
6204 | or else | |
6205 | (Expr_Value_R (Ck_Node) > Expr_Value_R (UB)); | |
6206 | ||
6207 | else -- fixed or discrete type | |
6208 | Out_Of_Range := | |
6209 | Expr_Value (Ck_Node) < Expr_Value (LB) | |
6210 | or else | |
6211 | Expr_Value (Ck_Node) > Expr_Value (UB); | |
6212 | end if; | |
6213 | ||
6214 | -- Bounds of the type are static and the literal is | |
6215 | -- out of range so make a warning message. | |
6216 | ||
6217 | if Out_Of_Range then | |
6218 | if No (Warn_Node) then | |
6219 | Add_Check | |
6220 | (Compile_Time_Constraint_Error | |
6221 | (Ck_Node, | |
6222 | "static value out of range of}?", T_Typ)); | |
6223 | ||
6224 | else | |
6225 | Add_Check | |
6226 | (Compile_Time_Constraint_Error | |
6227 | (Wnode, | |
6228 | "static value out of range of}?", T_Typ)); | |
6229 | end if; | |
6230 | end if; | |
6231 | ||
6232 | else | |
6233 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
6234 | end if; | |
6235 | end; | |
6236 | ||
6237 | -- Here for the case of a non-static expression, we need a runtime | |
6238 | -- check unless the source type range is guaranteed to be in the | |
6239 | -- range of the target type. | |
6240 | ||
6241 | else | |
6242 | if not In_Subrange_Of (S_Typ, T_Typ) then | |
6243 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
6244 | end if; | |
6245 | end if; | |
6246 | end if; | |
6247 | ||
6248 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
6249 | if Is_Constrained (T_Typ) then | |
6250 | ||
6251 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
6252 | Exptyp := Get_Actual_Subtype (Expr_Actual); | |
6253 | ||
6254 | if Is_Access_Type (Exptyp) then | |
6255 | Exptyp := Designated_Type (Exptyp); | |
6256 | end if; | |
6257 | ||
6258 | -- String_Literal case. This needs to be handled specially be- | |
6259 | -- cause no index types are available for string literals. The | |
6260 | -- condition is simply: | |
6261 | ||
6262 | -- T_Typ'Length = string-literal-length | |
6263 | ||
6264 | if Nkind (Expr_Actual) = N_String_Literal then | |
6265 | null; | |
6266 | ||
6267 | -- General array case. Here we have a usable actual subtype for | |
6268 | -- the expression, and the condition is built from the two types | |
6269 | ||
6270 | -- T_Typ'First < Exptyp'First or else | |
6271 | -- T_Typ'Last > Exptyp'Last or else | |
6272 | -- T_Typ'First(1) < Exptyp'First(1) or else | |
6273 | -- T_Typ'Last(1) > Exptyp'Last(1) or else | |
6274 | -- ... | |
6275 | ||
6276 | elsif Is_Constrained (Exptyp) then | |
6277 | declare | |
9dfe12ae | 6278 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
6279 | ||
ee6ba406 | 6280 | L_Index : Node_Id; |
6281 | R_Index : Node_Id; | |
9dfe12ae | 6282 | L_Low : Node_Id; |
6283 | L_High : Node_Id; | |
6284 | R_Low : Node_Id; | |
6285 | R_High : Node_Id; | |
ee6ba406 | 6286 | |
6287 | begin | |
6288 | L_Index := First_Index (T_Typ); | |
6289 | R_Index := First_Index (Exptyp); | |
6290 | ||
6291 | for Indx in 1 .. Ndims loop | |
6292 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 6293 | or else |
6294 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 6295 | then |
6296 | Get_Index_Bounds (L_Index, L_Low, L_High); | |
6297 | Get_Index_Bounds (R_Index, R_Low, R_High); | |
6298 | ||
6299 | -- Deal with compile time length check. Note that we | |
6300 | -- skip this in the access case, because the access | |
6301 | -- value may be null, so we cannot know statically. | |
6302 | ||
6303 | if not | |
6304 | Subtypes_Statically_Match | |
6305 | (Etype (L_Index), Etype (R_Index)) | |
6306 | then | |
6307 | -- If the target type is constrained then we | |
6308 | -- have to check for exact equality of bounds | |
6309 | -- (required for qualified expressions). | |
6310 | ||
6311 | if Is_Constrained (T_Typ) then | |
6312 | Evolve_Or_Else | |
6313 | (Cond, | |
6314 | Range_Equal_E_Cond (Exptyp, T_Typ, Indx)); | |
6315 | ||
6316 | else | |
6317 | Evolve_Or_Else | |
6318 | (Cond, Range_E_Cond (Exptyp, T_Typ, Indx)); | |
6319 | end if; | |
6320 | end if; | |
6321 | ||
6322 | Next (L_Index); | |
6323 | Next (R_Index); | |
6324 | ||
6325 | end if; | |
6326 | end loop; | |
6327 | end; | |
6328 | ||
6329 | -- Handle cases where we do not get a usable actual subtype that | |
6330 | -- is constrained. This happens for example in the function call | |
6331 | -- and explicit dereference cases. In these cases, we have to get | |
6332 | -- the length or range from the expression itself, making sure we | |
6333 | -- do not evaluate it more than once. | |
6334 | ||
6335 | -- Here Ck_Node is the original expression, or more properly the | |
6336 | -- result of applying Duplicate_Expr to the original tree, | |
6337 | -- forcing the result to be a name. | |
6338 | ||
6339 | else | |
6340 | declare | |
9dfe12ae | 6341 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 6342 | |
6343 | begin | |
6344 | -- Build the condition for the explicit dereference case | |
6345 | ||
6346 | for Indx in 1 .. Ndims loop | |
6347 | Evolve_Or_Else | |
6348 | (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx)); | |
6349 | end loop; | |
6350 | end; | |
6351 | ||
6352 | end if; | |
6353 | ||
6354 | else | |
6355 | -- Generate an Action to check that the bounds of the | |
6356 | -- source value are within the constraints imposed by the | |
6357 | -- target type for a conversion to an unconstrained type. | |
6358 | -- Rule is 4.6(38). | |
6359 | ||
6360 | if Nkind (Parent (Ck_Node)) = N_Type_Conversion then | |
6361 | declare | |
6362 | Opnd_Index : Node_Id; | |
6363 | Targ_Index : Node_Id; | |
6364 | ||
6365 | begin | |
6366 | Opnd_Index | |
6367 | := First_Index (Get_Actual_Subtype (Ck_Node)); | |
6368 | Targ_Index := First_Index (T_Typ); | |
6369 | ||
6370 | while Opnd_Index /= Empty loop | |
6371 | if Nkind (Opnd_Index) = N_Range then | |
6372 | if Is_In_Range | |
6373 | (Low_Bound (Opnd_Index), Etype (Targ_Index)) | |
6374 | and then | |
6375 | Is_In_Range | |
6376 | (High_Bound (Opnd_Index), Etype (Targ_Index)) | |
6377 | then | |
6378 | null; | |
6379 | ||
f2a06be9 | 6380 | -- If null range, no check needed |
6381 | ||
9dfe12ae | 6382 | elsif |
6383 | Compile_Time_Known_Value (High_Bound (Opnd_Index)) | |
6384 | and then | |
6385 | Compile_Time_Known_Value (Low_Bound (Opnd_Index)) | |
6386 | and then | |
f2a06be9 | 6387 | Expr_Value (High_Bound (Opnd_Index)) < |
6388 | Expr_Value (Low_Bound (Opnd_Index)) | |
9dfe12ae | 6389 | then |
6390 | null; | |
6391 | ||
ee6ba406 | 6392 | elsif Is_Out_Of_Range |
6393 | (Low_Bound (Opnd_Index), Etype (Targ_Index)) | |
6394 | or else | |
6395 | Is_Out_Of_Range | |
6396 | (High_Bound (Opnd_Index), Etype (Targ_Index)) | |
6397 | then | |
6398 | Add_Check | |
6399 | (Compile_Time_Constraint_Error | |
6400 | (Wnode, "value out of range of}?", T_Typ)); | |
6401 | ||
6402 | else | |
6403 | Evolve_Or_Else | |
6404 | (Cond, | |
6405 | Discrete_Range_Cond | |
6406 | (Opnd_Index, Etype (Targ_Index))); | |
6407 | end if; | |
6408 | end if; | |
6409 | ||
6410 | Next_Index (Opnd_Index); | |
6411 | Next_Index (Targ_Index); | |
6412 | end loop; | |
6413 | end; | |
6414 | end if; | |
6415 | end if; | |
6416 | end if; | |
6417 | ||
6418 | -- Construct the test and insert into the tree | |
6419 | ||
6420 | if Present (Cond) then | |
6421 | if Do_Access then | |
6422 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
6423 | end if; | |
6424 | ||
f15731c4 | 6425 | Add_Check |
6426 | (Make_Raise_Constraint_Error (Loc, | |
6427 | Condition => Cond, | |
6428 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 6429 | end if; |
6430 | ||
6431 | return Ret_Result; | |
ee6ba406 | 6432 | end Selected_Range_Checks; |
6433 | ||
6434 | ------------------------------- | |
6435 | -- Storage_Checks_Suppressed -- | |
6436 | ------------------------------- | |
6437 | ||
6438 | function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is | |
6439 | begin | |
9dfe12ae | 6440 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
6441 | return Is_Check_Suppressed (E, Storage_Check); | |
6442 | else | |
6443 | return Scope_Suppress (Storage_Check); | |
6444 | end if; | |
ee6ba406 | 6445 | end Storage_Checks_Suppressed; |
6446 | ||
6447 | --------------------------- | |
6448 | -- Tag_Checks_Suppressed -- | |
6449 | --------------------------- | |
6450 | ||
6451 | function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is | |
6452 | begin | |
9dfe12ae | 6453 | if Present (E) then |
6454 | if Kill_Tag_Checks (E) then | |
6455 | return True; | |
6456 | elsif Checks_May_Be_Suppressed (E) then | |
6457 | return Is_Check_Suppressed (E, Tag_Check); | |
6458 | end if; | |
6459 | end if; | |
6460 | ||
6461 | return Scope_Suppress (Tag_Check); | |
ee6ba406 | 6462 | end Tag_Checks_Suppressed; |
6463 | ||
6464 | end Checks; |