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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 | -- -- | |
dd688950 | 9 | -- Copyright (C) 1992-2011, Free Software Foundation, Inc. -- |
ee6ba406 | 10 | -- -- |
11 | -- GNAT is free software; you can redistribute it and/or modify it under -- | |
12 | -- terms of the GNU General Public License as published by the Free Soft- -- | |
80df182a | 13 | -- ware Foundation; either version 3, or (at your option) any later ver- -- |
ee6ba406 | 14 | -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
15 | -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- | |
16 | -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- | |
17 | -- for more details. You should have received a copy of the GNU General -- | |
80df182a | 18 | -- Public License distributed with GNAT; see file COPYING3. If not, go to -- |
19 | -- http://www.gnu.org/licenses for a complete copy of the license. -- | |
ee6ba406 | 20 | -- -- |
21 | -- GNAT was originally developed by the GNAT team at New York University. -- | |
e78e8c8e | 22 | -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
ee6ba406 | 23 | -- -- |
24 | ------------------------------------------------------------------------------ | |
25 | ||
26 | with Atree; use Atree; | |
27 | with Debug; use Debug; | |
28 | with Einfo; use Einfo; | |
29 | with Errout; use Errout; | |
30 | with Exp_Ch2; use Exp_Ch2; | |
df40eeb0 | 31 | with Exp_Ch4; use Exp_Ch4; |
00c403ee | 32 | with Exp_Ch11; use Exp_Ch11; |
05fcfafb | 33 | with Exp_Pakd; use Exp_Pakd; |
ee6ba406 | 34 | with Exp_Util; use Exp_Util; |
35 | with Elists; use Elists; | |
5329ca64 | 36 | with Eval_Fat; use Eval_Fat; |
ee6ba406 | 37 | with Freeze; use Freeze; |
9dfe12ae | 38 | with Lib; use Lib; |
ee6ba406 | 39 | with Nlists; use Nlists; |
40 | with Nmake; use Nmake; | |
41 | with Opt; use Opt; | |
9dfe12ae | 42 | with Output; use Output; |
c2b56224 | 43 | with Restrict; use Restrict; |
1e16c51c | 44 | with Rident; use Rident; |
ee6ba406 | 45 | with Rtsfind; use Rtsfind; |
46 | with Sem; use Sem; | |
d60c9ff7 | 47 | with Sem_Aux; use Sem_Aux; |
ee6ba406 | 48 | with Sem_Eval; use Sem_Eval; |
00f91aef | 49 | with Sem_Ch3; use Sem_Ch3; |
9dfe12ae | 50 | with Sem_Ch8; use Sem_Ch8; |
ee6ba406 | 51 | with Sem_Res; use Sem_Res; |
52 | with Sem_Util; use Sem_Util; | |
53 | with Sem_Warn; use Sem_Warn; | |
54 | with Sinfo; use Sinfo; | |
9dfe12ae | 55 | with Sinput; use Sinput; |
ee6ba406 | 56 | with Snames; use Snames; |
9dfe12ae | 57 | with Sprint; use Sprint; |
ee6ba406 | 58 | with Stand; use Stand; |
f15731c4 | 59 | with Targparm; use Targparm; |
ee6ba406 | 60 | with Tbuild; use Tbuild; |
61 | with Ttypes; use Ttypes; | |
62 | with Urealp; use Urealp; | |
63 | with Validsw; use Validsw; | |
64 | ||
65 | package body Checks is | |
66 | ||
67 | -- General note: many of these routines are concerned with generating | |
68 | -- checking code to make sure that constraint error is raised at runtime. | |
69 | -- Clearly this code is only needed if the expander is active, since | |
70 | -- otherwise we will not be generating code or going into the runtime | |
71 | -- execution anyway. | |
72 | ||
73 | -- We therefore disconnect most of these checks if the expander is | |
74 | -- inactive. This has the additional benefit that we do not need to | |
75 | -- worry about the tree being messed up by previous errors (since errors | |
76 | -- turn off expansion anyway). | |
77 | ||
78 | -- There are a few exceptions to the above rule. For instance routines | |
79 | -- such as Apply_Scalar_Range_Check that do not insert any code can be | |
80 | -- safely called even when the Expander is inactive (but Errors_Detected | |
81 | -- is 0). The benefit of executing this code when expansion is off, is | |
82 | -- the ability to emit constraint error warning for static expressions | |
83 | -- even when we are not generating code. | |
84 | ||
9dfe12ae | 85 | ------------------------------------- |
86 | -- Suppression of Redundant Checks -- | |
87 | ------------------------------------- | |
88 | ||
89 | -- This unit implements a limited circuit for removal of redundant | |
90 | -- checks. The processing is based on a tracing of simple sequential | |
91 | -- flow. For any sequence of statements, we save expressions that are | |
92 | -- marked to be checked, and then if the same expression appears later | |
93 | -- with the same check, then under certain circumstances, the second | |
94 | -- check can be suppressed. | |
95 | ||
96 | -- Basically, we can suppress the check if we know for certain that | |
97 | -- the previous expression has been elaborated (together with its | |
98 | -- check), and we know that the exception frame is the same, and that | |
99 | -- nothing has happened to change the result of the exception. | |
100 | ||
101 | -- Let us examine each of these three conditions in turn to describe | |
102 | -- how we ensure that this condition is met. | |
103 | ||
104 | -- First, we need to know for certain that the previous expression has | |
6fb3c314 | 105 | -- been executed. This is done principally by the mechanism of calling |
9dfe12ae | 106 | -- Conditional_Statements_Begin at the start of any statement sequence |
107 | -- and Conditional_Statements_End at the end. The End call causes all | |
108 | -- checks remembered since the Begin call to be discarded. This does | |
109 | -- miss a few cases, notably the case of a nested BEGIN-END block with | |
110 | -- no exception handlers. But the important thing is to be conservative. | |
111 | -- The other protection is that all checks are discarded if a label | |
112 | -- is encountered, since then the assumption of sequential execution | |
113 | -- is violated, and we don't know enough about the flow. | |
114 | ||
115 | -- Second, we need to know that the exception frame is the same. We | |
116 | -- do this by killing all remembered checks when we enter a new frame. | |
117 | -- Again, that's over-conservative, but generally the cases we can help | |
118 | -- with are pretty local anyway (like the body of a loop for example). | |
119 | ||
120 | -- Third, we must be sure to forget any checks which are no longer valid. | |
121 | -- This is done by two mechanisms, first the Kill_Checks_Variable call is | |
122 | -- used to note any changes to local variables. We only attempt to deal | |
123 | -- with checks involving local variables, so we do not need to worry | |
124 | -- about global variables. Second, a call to any non-global procedure | |
125 | -- causes us to abandon all stored checks, since such a all may affect | |
126 | -- the values of any local variables. | |
127 | ||
128 | -- The following define the data structures used to deal with remembering | |
129 | -- checks so that redundant checks can be eliminated as described above. | |
130 | ||
131 | -- Right now, the only expressions that we deal with are of the form of | |
132 | -- simple local objects (either declared locally, or IN parameters) or | |
133 | -- such objects plus/minus a compile time known constant. We can do | |
134 | -- more later on if it seems worthwhile, but this catches many simple | |
135 | -- cases in practice. | |
136 | ||
137 | -- The following record type reflects a single saved check. An entry | |
138 | -- is made in the stack of saved checks if and only if the expression | |
139 | -- has been elaborated with the indicated checks. | |
140 | ||
141 | type Saved_Check is record | |
142 | Killed : Boolean; | |
143 | -- Set True if entry is killed by Kill_Checks | |
144 | ||
145 | Entity : Entity_Id; | |
146 | -- The entity involved in the expression that is checked | |
147 | ||
148 | Offset : Uint; | |
149 | -- A compile time value indicating the result of adding or | |
150 | -- subtracting a compile time value. This value is to be | |
151 | -- added to the value of the Entity. A value of zero is | |
152 | -- used for the case of a simple entity reference. | |
153 | ||
154 | Check_Type : Character; | |
155 | -- This is set to 'R' for a range check (in which case Target_Type | |
156 | -- is set to the target type for the range check) or to 'O' for an | |
157 | -- overflow check (in which case Target_Type is set to Empty). | |
158 | ||
159 | Target_Type : Entity_Id; | |
160 | -- Used only if Do_Range_Check is set. Records the target type for | |
161 | -- the check. We need this, because a check is a duplicate only if | |
6fb3c314 | 162 | -- it has the same target type (or more accurately one with a |
9dfe12ae | 163 | -- range that is smaller or equal to the stored target type of a |
164 | -- saved check). | |
165 | end record; | |
166 | ||
167 | -- The following table keeps track of saved checks. Rather than use an | |
168 | -- extensible table. We just use a table of fixed size, and we discard | |
169 | -- any saved checks that do not fit. That's very unlikely to happen and | |
170 | -- this is only an optimization in any case. | |
171 | ||
172 | Saved_Checks : array (Int range 1 .. 200) of Saved_Check; | |
173 | -- Array of saved checks | |
174 | ||
175 | Num_Saved_Checks : Nat := 0; | |
176 | -- Number of saved checks | |
177 | ||
178 | -- The following stack keeps track of statement ranges. It is treated | |
179 | -- as a stack. When Conditional_Statements_Begin is called, an entry | |
180 | -- is pushed onto this stack containing the value of Num_Saved_Checks | |
181 | -- at the time of the call. Then when Conditional_Statements_End is | |
182 | -- called, this value is popped off and used to reset Num_Saved_Checks. | |
183 | ||
184 | -- Note: again, this is a fixed length stack with a size that should | |
185 | -- always be fine. If the value of the stack pointer goes above the | |
186 | -- limit, then we just forget all saved checks. | |
187 | ||
188 | Saved_Checks_Stack : array (Int range 1 .. 100) of Nat; | |
189 | Saved_Checks_TOS : Nat := 0; | |
190 | ||
191 | ----------------------- | |
192 | -- Local Subprograms -- | |
193 | ----------------------- | |
ee6ba406 | 194 | |
5329ca64 | 195 | procedure Apply_Float_Conversion_Check |
196 | (Ck_Node : Node_Id; | |
197 | Target_Typ : Entity_Id); | |
198 | -- The checks on a conversion from a floating-point type to an integer | |
199 | -- type are delicate. They have to be performed before conversion, they | |
200 | -- have to raise an exception when the operand is a NaN, and rounding must | |
201 | -- be taken into account to determine the safe bounds of the operand. | |
202 | ||
ee6ba406 | 203 | procedure Apply_Selected_Length_Checks |
204 | (Ck_Node : Node_Id; | |
205 | Target_Typ : Entity_Id; | |
206 | Source_Typ : Entity_Id; | |
207 | Do_Static : Boolean); | |
208 | -- This is the subprogram that does all the work for Apply_Length_Check | |
209 | -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as | |
210 | -- described for the above routines. The Do_Static flag indicates that | |
211 | -- only a static check is to be done. | |
212 | ||
213 | procedure Apply_Selected_Range_Checks | |
214 | (Ck_Node : Node_Id; | |
215 | Target_Typ : Entity_Id; | |
216 | Source_Typ : Entity_Id; | |
217 | Do_Static : Boolean); | |
218 | -- This is the subprogram that does all the work for Apply_Range_Check. | |
219 | -- Expr, Target_Typ and Source_Typ are as described for the above | |
220 | -- routine. The Do_Static flag indicates that only a static check is | |
221 | -- to be done. | |
222 | ||
2af58f67 | 223 | type Check_Type is new Check_Id range Access_Check .. Division_Check; |
13dbf220 | 224 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean; |
225 | -- This function is used to see if an access or division by zero check is | |
226 | -- needed. The check is to be applied to a single variable appearing in the | |
227 | -- source, and N is the node for the reference. If N is not of this form, | |
228 | -- True is returned with no further processing. If N is of the right form, | |
229 | -- then further processing determines if the given Check is needed. | |
230 | -- | |
231 | -- The particular circuit is to see if we have the case of a check that is | |
232 | -- not needed because it appears in the right operand of a short circuited | |
233 | -- conditional where the left operand guards the check. For example: | |
234 | -- | |
235 | -- if Var = 0 or else Q / Var > 12 then | |
236 | -- ... | |
237 | -- end if; | |
238 | -- | |
239 | -- In this example, the division check is not required. At the same time | |
240 | -- we can issue warnings for suspicious use of non-short-circuited forms, | |
241 | -- such as: | |
242 | -- | |
243 | -- if Var = 0 or Q / Var > 12 then | |
244 | -- ... | |
245 | -- end if; | |
246 | ||
9dfe12ae | 247 | procedure Find_Check |
248 | (Expr : Node_Id; | |
249 | Check_Type : Character; | |
250 | Target_Type : Entity_Id; | |
251 | Entry_OK : out Boolean; | |
252 | Check_Num : out Nat; | |
253 | Ent : out Entity_Id; | |
254 | Ofs : out Uint); | |
255 | -- This routine is used by Enable_Range_Check and Enable_Overflow_Check | |
256 | -- to see if a check is of the form for optimization, and if so, to see | |
257 | -- if it has already been performed. Expr is the expression to check, | |
258 | -- and Check_Type is 'R' for a range check, 'O' for an overflow check. | |
259 | -- Target_Type is the target type for a range check, and Empty for an | |
260 | -- overflow check. If the entry is not of the form for optimization, | |
261 | -- then Entry_OK is set to False, and the remaining out parameters | |
262 | -- are undefined. If the entry is OK, then Ent/Ofs are set to the | |
263 | -- entity and offset from the expression. Check_Num is the number of | |
264 | -- a matching saved entry in Saved_Checks, or zero if no such entry | |
265 | -- is located. | |
266 | ||
ee6ba406 | 267 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id; |
268 | -- If a discriminal is used in constraining a prival, Return reference | |
269 | -- to the discriminal of the protected body (which renames the parameter | |
270 | -- of the enclosing protected operation). This clumsy transformation is | |
271 | -- needed because privals are created too late and their actual subtypes | |
272 | -- are not available when analysing the bodies of the protected operations. | |
0577b0b1 | 273 | -- This function is called whenever the bound is an entity and the scope |
274 | -- indicates a protected operation. If the bound is an in-parameter of | |
275 | -- a protected operation that is not a prival, the function returns the | |
276 | -- bound itself. | |
ee6ba406 | 277 | -- To be cleaned up??? |
278 | ||
279 | function Guard_Access | |
280 | (Cond : Node_Id; | |
281 | Loc : Source_Ptr; | |
314a23b6 | 282 | Ck_Node : Node_Id) return Node_Id; |
ee6ba406 | 283 | -- In the access type case, guard the test with a test to ensure |
284 | -- that the access value is non-null, since the checks do not | |
285 | -- not apply to null access values. | |
286 | ||
287 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr); | |
288 | -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the | |
289 | -- Constraint_Error node. | |
290 | ||
0577b0b1 | 291 | function Range_Or_Validity_Checks_Suppressed |
292 | (Expr : Node_Id) return Boolean; | |
293 | -- Returns True if either range or validity checks or both are suppressed | |
294 | -- for the type of the given expression, or, if the expression is the name | |
295 | -- of an entity, if these checks are suppressed for the entity. | |
296 | ||
ee6ba406 | 297 | function Selected_Length_Checks |
298 | (Ck_Node : Node_Id; | |
299 | Target_Typ : Entity_Id; | |
300 | Source_Typ : Entity_Id; | |
314a23b6 | 301 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 302 | -- Like Apply_Selected_Length_Checks, except it doesn't modify |
303 | -- anything, just returns a list of nodes as described in the spec of | |
304 | -- this package for the Range_Check function. | |
305 | ||
306 | function Selected_Range_Checks | |
307 | (Ck_Node : Node_Id; | |
308 | Target_Typ : Entity_Id; | |
309 | Source_Typ : Entity_Id; | |
314a23b6 | 310 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 311 | -- Like Apply_Selected_Range_Checks, except it doesn't modify anything, |
312 | -- just returns a list of nodes as described in the spec of this package | |
313 | -- for the Range_Check function. | |
314 | ||
315 | ------------------------------ | |
316 | -- Access_Checks_Suppressed -- | |
317 | ------------------------------ | |
318 | ||
319 | function Access_Checks_Suppressed (E : Entity_Id) return Boolean is | |
320 | begin | |
9dfe12ae | 321 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
322 | return Is_Check_Suppressed (E, Access_Check); | |
323 | else | |
324 | return Scope_Suppress (Access_Check); | |
325 | end if; | |
ee6ba406 | 326 | end Access_Checks_Suppressed; |
327 | ||
328 | ------------------------------------- | |
329 | -- Accessibility_Checks_Suppressed -- | |
330 | ------------------------------------- | |
331 | ||
332 | function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is | |
333 | begin | |
9dfe12ae | 334 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
335 | return Is_Check_Suppressed (E, Accessibility_Check); | |
336 | else | |
337 | return Scope_Suppress (Accessibility_Check); | |
338 | end if; | |
ee6ba406 | 339 | end Accessibility_Checks_Suppressed; |
340 | ||
00c403ee | 341 | ----------------------------- |
342 | -- Activate_Division_Check -- | |
343 | ----------------------------- | |
344 | ||
345 | procedure Activate_Division_Check (N : Node_Id) is | |
346 | begin | |
347 | Set_Do_Division_Check (N, True); | |
348 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
349 | end Activate_Division_Check; | |
350 | ||
351 | ----------------------------- | |
352 | -- Activate_Overflow_Check -- | |
353 | ----------------------------- | |
354 | ||
355 | procedure Activate_Overflow_Check (N : Node_Id) is | |
356 | begin | |
357 | Set_Do_Overflow_Check (N, True); | |
358 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
359 | end Activate_Overflow_Check; | |
360 | ||
361 | -------------------------- | |
362 | -- Activate_Range_Check -- | |
363 | -------------------------- | |
364 | ||
365 | procedure Activate_Range_Check (N : Node_Id) is | |
366 | begin | |
367 | Set_Do_Range_Check (N, True); | |
368 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
369 | end Activate_Range_Check; | |
370 | ||
0577b0b1 | 371 | --------------------------------- |
372 | -- Alignment_Checks_Suppressed -- | |
373 | --------------------------------- | |
374 | ||
375 | function Alignment_Checks_Suppressed (E : Entity_Id) return Boolean is | |
376 | begin | |
377 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
378 | return Is_Check_Suppressed (E, Alignment_Check); | |
379 | else | |
380 | return Scope_Suppress (Alignment_Check); | |
381 | end if; | |
382 | end Alignment_Checks_Suppressed; | |
383 | ||
ee6ba406 | 384 | ------------------------- |
385 | -- Append_Range_Checks -- | |
386 | ------------------------- | |
387 | ||
388 | procedure Append_Range_Checks | |
389 | (Checks : Check_Result; | |
390 | Stmts : List_Id; | |
391 | Suppress_Typ : Entity_Id; | |
392 | Static_Sloc : Source_Ptr; | |
393 | Flag_Node : Node_Id) | |
394 | is | |
9dfe12ae | 395 | Internal_Flag_Node : constant Node_Id := Flag_Node; |
396 | Internal_Static_Sloc : constant Source_Ptr := Static_Sloc; | |
397 | ||
ee6ba406 | 398 | Checks_On : constant Boolean := |
399 | (not Index_Checks_Suppressed (Suppress_Typ)) | |
400 | or else | |
401 | (not Range_Checks_Suppressed (Suppress_Typ)); | |
402 | ||
403 | begin | |
404 | -- For now we just return if Checks_On is false, however this should | |
405 | -- be enhanced to check for an always True value in the condition | |
406 | -- and to generate a compilation warning??? | |
407 | ||
408 | if not Checks_On then | |
409 | return; | |
410 | end if; | |
411 | ||
412 | for J in 1 .. 2 loop | |
413 | exit when No (Checks (J)); | |
414 | ||
415 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
416 | and then Present (Condition (Checks (J))) | |
417 | then | |
418 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
419 | Append_To (Stmts, Checks (J)); | |
420 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
421 | end if; | |
422 | ||
423 | else | |
424 | Append_To | |
f15731c4 | 425 | (Stmts, |
426 | Make_Raise_Constraint_Error (Internal_Static_Sloc, | |
427 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 428 | end if; |
429 | end loop; | |
430 | end Append_Range_Checks; | |
431 | ||
432 | ------------------------ | |
433 | -- Apply_Access_Check -- | |
434 | ------------------------ | |
435 | ||
436 | procedure Apply_Access_Check (N : Node_Id) is | |
437 | P : constant Node_Id := Prefix (N); | |
438 | ||
439 | begin | |
13dbf220 | 440 | -- We do not need checks if we are not generating code (i.e. the |
441 | -- expander is not active). This is not just an optimization, there | |
442 | -- are cases (e.g. with pragma Debug) where generating the checks | |
443 | -- can cause real trouble). | |
284faf8b | 444 | |
84d0d4a5 | 445 | if not Expander_Active then |
13dbf220 | 446 | return; |
9dfe12ae | 447 | end if; |
ee6ba406 | 448 | |
84d0d4a5 | 449 | -- No check if short circuiting makes check unnecessary |
9dfe12ae | 450 | |
84d0d4a5 | 451 | if not Check_Needed (P, Access_Check) then |
452 | return; | |
ee6ba406 | 453 | end if; |
9dfe12ae | 454 | |
cc60bd16 | 455 | -- No check if accessing the Offset_To_Top component of a dispatch |
456 | -- table. They are safe by construction. | |
457 | ||
040277b1 | 458 | if Tagged_Type_Expansion |
459 | and then Present (Etype (P)) | |
cc60bd16 | 460 | and then RTU_Loaded (Ada_Tags) |
461 | and then RTE_Available (RE_Offset_To_Top_Ptr) | |
462 | and then Etype (P) = RTE (RE_Offset_To_Top_Ptr) | |
463 | then | |
464 | return; | |
465 | end if; | |
466 | ||
84d0d4a5 | 467 | -- Otherwise go ahead and install the check |
9dfe12ae | 468 | |
fa7497e8 | 469 | Install_Null_Excluding_Check (P); |
ee6ba406 | 470 | end Apply_Access_Check; |
471 | ||
472 | ------------------------------- | |
473 | -- Apply_Accessibility_Check -- | |
474 | ------------------------------- | |
475 | ||
55dc6dc2 | 476 | procedure Apply_Accessibility_Check |
477 | (N : Node_Id; | |
478 | Typ : Entity_Id; | |
479 | Insert_Node : Node_Id) | |
480 | is | |
ee6ba406 | 481 | Loc : constant Source_Ptr := Sloc (N); |
47d210a3 | 482 | Param_Ent : Entity_Id := Param_Entity (N); |
ee6ba406 | 483 | Param_Level : Node_Id; |
484 | Type_Level : Node_Id; | |
485 | ||
486 | begin | |
47d210a3 | 487 | if Ada_Version >= Ada_2012 |
488 | and then not Present (Param_Ent) | |
489 | and then Is_Entity_Name (N) | |
490 | and then Ekind_In (Entity (N), E_Constant, E_Variable) | |
491 | and then Present (Effective_Extra_Accessibility (Entity (N))) | |
492 | then | |
493 | Param_Ent := Entity (N); | |
494 | while Present (Renamed_Object (Param_Ent)) loop | |
495 | -- Renamed_Object must return an Entity_Name here | |
496 | -- because of preceding "Present (E_E_A (...))" test. | |
497 | ||
498 | Param_Ent := Entity (Renamed_Object (Param_Ent)); | |
499 | end loop; | |
500 | end if; | |
501 | ||
ee6ba406 | 502 | if Inside_A_Generic then |
503 | return; | |
504 | ||
6ffc64fc | 505 | -- Only apply the run-time check if the access parameter has an |
506 | -- associated extra access level parameter and when the level of the | |
507 | -- type is less deep than the level of the access parameter, and | |
508 | -- accessibility checks are not suppressed. | |
ee6ba406 | 509 | |
510 | elsif Present (Param_Ent) | |
511 | and then Present (Extra_Accessibility (Param_Ent)) | |
47d210a3 | 512 | and then UI_Gt (Object_Access_Level (N), |
513 | Deepest_Type_Access_Level (Typ)) | |
ee6ba406 | 514 | and then not Accessibility_Checks_Suppressed (Param_Ent) |
515 | and then not Accessibility_Checks_Suppressed (Typ) | |
516 | then | |
517 | Param_Level := | |
518 | New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc); | |
519 | ||
47d210a3 | 520 | Type_Level := Make_Integer_Literal (Loc, |
521 | Deepest_Type_Access_Level (Typ)); | |
ee6ba406 | 522 | |
bf3e1520 | 523 | -- Raise Program_Error if the accessibility level of the access |
84d0d4a5 | 524 | -- parameter is deeper than the level of the target access type. |
ee6ba406 | 525 | |
55dc6dc2 | 526 | Insert_Action (Insert_Node, |
ee6ba406 | 527 | Make_Raise_Program_Error (Loc, |
528 | Condition => | |
529 | Make_Op_Gt (Loc, | |
530 | Left_Opnd => Param_Level, | |
f15731c4 | 531 | Right_Opnd => Type_Level), |
532 | Reason => PE_Accessibility_Check_Failed)); | |
ee6ba406 | 533 | |
534 | Analyze_And_Resolve (N); | |
535 | end if; | |
536 | end Apply_Accessibility_Check; | |
537 | ||
0577b0b1 | 538 | -------------------------------- |
539 | -- Apply_Address_Clause_Check -- | |
540 | -------------------------------- | |
541 | ||
542 | procedure Apply_Address_Clause_Check (E : Entity_Id; N : Node_Id) is | |
543 | AC : constant Node_Id := Address_Clause (E); | |
544 | Loc : constant Source_Ptr := Sloc (AC); | |
545 | Typ : constant Entity_Id := Etype (E); | |
546 | Aexp : constant Node_Id := Expression (AC); | |
c2b56224 | 547 | |
c2b56224 | 548 | Expr : Node_Id; |
0577b0b1 | 549 | -- Address expression (not necessarily the same as Aexp, for example |
550 | -- when Aexp is a reference to a constant, in which case Expr gets | |
551 | -- reset to reference the value expression of the constant. | |
552 | ||
0577b0b1 | 553 | procedure Compile_Time_Bad_Alignment; |
554 | -- Post error warnings when alignment is known to be incompatible. Note | |
555 | -- that we do not go as far as inserting a raise of Program_Error since | |
556 | -- this is an erroneous case, and it may happen that we are lucky and an | |
d6da7448 | 557 | -- underaligned address turns out to be OK after all. |
0577b0b1 | 558 | |
559 | -------------------------------- | |
560 | -- Compile_Time_Bad_Alignment -- | |
561 | -------------------------------- | |
562 | ||
563 | procedure Compile_Time_Bad_Alignment is | |
564 | begin | |
d6da7448 | 565 | if Address_Clause_Overlay_Warnings then |
0577b0b1 | 566 | Error_Msg_FE |
567 | ("?specified address for& may be inconsistent with alignment ", | |
568 | Aexp, E); | |
569 | Error_Msg_FE | |
2af58f67 | 570 | ("\?program execution may be erroneous (RM 13.3(27))", |
0577b0b1 | 571 | Aexp, E); |
83f8f0a6 | 572 | Set_Address_Warning_Posted (AC); |
0577b0b1 | 573 | end if; |
574 | end Compile_Time_Bad_Alignment; | |
c2b56224 | 575 | |
2af58f67 | 576 | -- Start of processing for Apply_Address_Clause_Check |
5c61a0ff | 577 | |
c2b56224 | 578 | begin |
d6da7448 | 579 | -- See if alignment check needed. Note that we never need a check if the |
580 | -- maximum alignment is one, since the check will always succeed. | |
581 | ||
582 | -- Note: we do not check for checks suppressed here, since that check | |
583 | -- was done in Sem_Ch13 when the address clause was processed. We are | |
584 | -- only called if checks were not suppressed. The reason for this is | |
585 | -- that we have to delay the call to Apply_Alignment_Check till freeze | |
586 | -- time (so that all types etc are elaborated), but we have to check | |
587 | -- the status of check suppressing at the point of the address clause. | |
588 | ||
589 | if No (AC) | |
590 | or else not Check_Address_Alignment (AC) | |
591 | or else Maximum_Alignment = 1 | |
592 | then | |
593 | return; | |
594 | end if; | |
595 | ||
596 | -- Obtain expression from address clause | |
9dfe12ae | 597 | |
0577b0b1 | 598 | Expr := Expression (AC); |
599 | ||
600 | -- The following loop digs for the real expression to use in the check | |
601 | ||
602 | loop | |
603 | -- For constant, get constant expression | |
604 | ||
605 | if Is_Entity_Name (Expr) | |
606 | and then Ekind (Entity (Expr)) = E_Constant | |
607 | then | |
608 | Expr := Constant_Value (Entity (Expr)); | |
609 | ||
610 | -- For unchecked conversion, get result to convert | |
611 | ||
612 | elsif Nkind (Expr) = N_Unchecked_Type_Conversion then | |
613 | Expr := Expression (Expr); | |
614 | ||
615 | -- For (common case) of To_Address call, get argument | |
616 | ||
617 | elsif Nkind (Expr) = N_Function_Call | |
618 | and then Is_Entity_Name (Name (Expr)) | |
619 | and then Is_RTE (Entity (Name (Expr)), RE_To_Address) | |
620 | then | |
621 | Expr := First (Parameter_Associations (Expr)); | |
622 | ||
623 | if Nkind (Expr) = N_Parameter_Association then | |
624 | Expr := Explicit_Actual_Parameter (Expr); | |
625 | end if; | |
626 | ||
627 | -- We finally have the real expression | |
628 | ||
629 | else | |
630 | exit; | |
631 | end if; | |
632 | end loop; | |
633 | ||
d6da7448 | 634 | -- See if we know that Expr has a bad alignment at compile time |
c2b56224 | 635 | |
636 | if Compile_Time_Known_Value (Expr) | |
f2a06be9 | 637 | and then (Known_Alignment (E) or else Known_Alignment (Typ)) |
c2b56224 | 638 | then |
f2a06be9 | 639 | declare |
640 | AL : Uint := Alignment (Typ); | |
641 | ||
642 | begin | |
643 | -- The object alignment might be more restrictive than the | |
644 | -- type alignment. | |
645 | ||
646 | if Known_Alignment (E) then | |
647 | AL := Alignment (E); | |
648 | end if; | |
649 | ||
650 | if Expr_Value (Expr) mod AL /= 0 then | |
0577b0b1 | 651 | Compile_Time_Bad_Alignment; |
652 | else | |
653 | return; | |
f2a06be9 | 654 | end if; |
655 | end; | |
c2b56224 | 656 | |
0577b0b1 | 657 | -- If the expression has the form X'Address, then we can find out if |
658 | -- the object X has an alignment that is compatible with the object E. | |
d6da7448 | 659 | -- If it hasn't or we don't know, we defer issuing the warning until |
660 | -- the end of the compilation to take into account back end annotations. | |
c2b56224 | 661 | |
0577b0b1 | 662 | elsif Nkind (Expr) = N_Attribute_Reference |
663 | and then Attribute_Name (Expr) = Name_Address | |
d6da7448 | 664 | and then Has_Compatible_Alignment (E, Prefix (Expr)) = Known_Compatible |
0577b0b1 | 665 | then |
d6da7448 | 666 | return; |
0577b0b1 | 667 | end if; |
c2b56224 | 668 | |
6fb3c314 | 669 | -- Here we do not know if the value is acceptable. Strictly we don't |
670 | -- have to do anything, since if the alignment is bad, we have an | |
671 | -- erroneous program. However we are allowed to check for erroneous | |
672 | -- conditions and we decide to do this by default if the check is not | |
673 | -- suppressed. | |
0577b0b1 | 674 | |
675 | -- However, don't do the check if elaboration code is unwanted | |
676 | ||
677 | if Restriction_Active (No_Elaboration_Code) then | |
678 | return; | |
679 | ||
680 | -- Generate a check to raise PE if alignment may be inappropriate | |
681 | ||
682 | else | |
683 | -- If the original expression is a non-static constant, use the | |
684 | -- name of the constant itself rather than duplicating its | |
00c403ee | 685 | -- defining expression, which was extracted above. |
0577b0b1 | 686 | |
00c403ee | 687 | -- Note: Expr is empty if the address-clause is applied to in-mode |
688 | -- actuals (allowed by 13.1(22)). | |
689 | ||
690 | if not Present (Expr) | |
691 | or else | |
692 | (Is_Entity_Name (Expression (AC)) | |
693 | and then Ekind (Entity (Expression (AC))) = E_Constant | |
694 | and then Nkind (Parent (Entity (Expression (AC)))) | |
695 | = N_Object_Declaration) | |
0577b0b1 | 696 | then |
697 | Expr := New_Copy_Tree (Expression (AC)); | |
698 | else | |
699 | Remove_Side_Effects (Expr); | |
c2b56224 | 700 | end if; |
c2b56224 | 701 | |
0577b0b1 | 702 | Insert_After_And_Analyze (N, |
703 | Make_Raise_Program_Error (Loc, | |
704 | Condition => | |
705 | Make_Op_Ne (Loc, | |
706 | Left_Opnd => | |
707 | Make_Op_Mod (Loc, | |
708 | Left_Opnd => | |
709 | Unchecked_Convert_To | |
710 | (RTE (RE_Integer_Address), Expr), | |
711 | Right_Opnd => | |
712 | Make_Attribute_Reference (Loc, | |
713 | Prefix => New_Occurrence_Of (E, Loc), | |
714 | Attribute_Name => Name_Alignment)), | |
715 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
716 | Reason => PE_Misaligned_Address_Value), | |
717 | Suppress => All_Checks); | |
718 | return; | |
719 | end if; | |
9dfe12ae | 720 | |
721 | exception | |
0577b0b1 | 722 | -- If we have some missing run time component in configurable run time |
723 | -- mode then just skip the check (it is not required in any case). | |
724 | ||
9dfe12ae | 725 | when RE_Not_Available => |
726 | return; | |
0577b0b1 | 727 | end Apply_Address_Clause_Check; |
c2b56224 | 728 | |
ee6ba406 | 729 | ------------------------------------- |
730 | -- Apply_Arithmetic_Overflow_Check -- | |
731 | ------------------------------------- | |
732 | ||
f40f9731 | 733 | -- This routine is called only if the type is an integer type, and a |
734 | -- software arithmetic overflow check may be needed for op (add, subtract, | |
735 | -- or multiply). This check is performed only if Software_Overflow_Checking | |
736 | -- is enabled and Do_Overflow_Check is set. In this case we expand the | |
737 | -- operation into a more complex sequence of tests that ensures that | |
738 | -- overflow is properly caught. | |
ee6ba406 | 739 | |
740 | procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is | |
741 | Loc : constant Source_Ptr := Sloc (N); | |
780bfb21 | 742 | Typ : constant Entity_Id := Etype (N); |
743 | Rtyp : constant Entity_Id := Root_Type (Typ); | |
ee6ba406 | 744 | |
745 | begin | |
f40f9731 | 746 | -- An interesting special case. If the arithmetic operation appears as |
747 | -- the operand of a type conversion: | |
748 | ||
749 | -- type1 (x op y) | |
750 | ||
751 | -- and all the following conditions apply: | |
752 | ||
753 | -- arithmetic operation is for a signed integer type | |
754 | -- target type type1 is a static integer subtype | |
755 | -- range of x and y are both included in the range of type1 | |
756 | -- range of x op y is included in the range of type1 | |
757 | -- size of type1 is at least twice the result size of op | |
758 | ||
759 | -- then we don't do an overflow check in any case, instead we transform | |
760 | -- the operation so that we end up with: | |
761 | ||
762 | -- type1 (type1 (x) op type1 (y)) | |
763 | ||
764 | -- This avoids intermediate overflow before the conversion. It is | |
765 | -- explicitly permitted by RM 3.5.4(24): | |
766 | ||
767 | -- For the execution of a predefined operation of a signed integer | |
768 | -- type, the implementation need not raise Constraint_Error if the | |
769 | -- result is outside the base range of the type, so long as the | |
770 | -- correct result is produced. | |
771 | ||
772 | -- It's hard to imagine that any programmer counts on the exception | |
773 | -- being raised in this case, and in any case it's wrong coding to | |
774 | -- have this expectation, given the RM permission. Furthermore, other | |
775 | -- Ada compilers do allow such out of range results. | |
776 | ||
777 | -- Note that we do this transformation even if overflow checking is | |
778 | -- off, since this is precisely about giving the "right" result and | |
779 | -- avoiding the need for an overflow check. | |
780 | ||
8eb4a5eb | 781 | -- Note: this circuit is partially redundant with respect to the similar |
782 | -- processing in Exp_Ch4.Expand_N_Type_Conversion, but the latter deals | |
783 | -- with cases that do not come through here. We still need the following | |
784 | -- processing even with the Exp_Ch4 code in place, since we want to be | |
785 | -- sure not to generate the arithmetic overflow check in these cases | |
786 | -- (Exp_Ch4 would have a hard time removing them once generated). | |
787 | ||
f40f9731 | 788 | if Is_Signed_Integer_Type (Typ) |
789 | and then Nkind (Parent (N)) = N_Type_Conversion | |
ee6ba406 | 790 | then |
f40f9731 | 791 | declare |
792 | Target_Type : constant Entity_Id := | |
793 | Base_Type (Entity (Subtype_Mark (Parent (N)))); | |
794 | ||
795 | Llo, Lhi : Uint; | |
796 | Rlo, Rhi : Uint; | |
797 | LOK, ROK : Boolean; | |
798 | ||
799 | Vlo : Uint; | |
800 | Vhi : Uint; | |
801 | VOK : Boolean; | |
802 | ||
803 | Tlo : Uint; | |
804 | Thi : Uint; | |
805 | ||
806 | begin | |
807 | if Is_Integer_Type (Target_Type) | |
808 | and then RM_Size (Root_Type (Target_Type)) >= 2 * RM_Size (Rtyp) | |
809 | then | |
810 | Tlo := Expr_Value (Type_Low_Bound (Target_Type)); | |
811 | Thi := Expr_Value (Type_High_Bound (Target_Type)); | |
812 | ||
9c486805 | 813 | Determine_Range |
814 | (Left_Opnd (N), LOK, Llo, Lhi, Assume_Valid => True); | |
815 | Determine_Range | |
816 | (Right_Opnd (N), ROK, Rlo, Rhi, Assume_Valid => True); | |
f40f9731 | 817 | |
818 | if (LOK and ROK) | |
819 | and then Tlo <= Llo and then Lhi <= Thi | |
820 | and then Tlo <= Rlo and then Rhi <= Thi | |
821 | then | |
9c486805 | 822 | Determine_Range (N, VOK, Vlo, Vhi, Assume_Valid => True); |
f40f9731 | 823 | |
824 | if VOK and then Tlo <= Vlo and then Vhi <= Thi then | |
825 | Rewrite (Left_Opnd (N), | |
826 | Make_Type_Conversion (Loc, | |
827 | Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), | |
828 | Expression => Relocate_Node (Left_Opnd (N)))); | |
829 | ||
830 | Rewrite (Right_Opnd (N), | |
831 | Make_Type_Conversion (Loc, | |
832 | Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), | |
833 | Expression => Relocate_Node (Right_Opnd (N)))); | |
834 | ||
780bfb21 | 835 | -- Rewrite the conversion operand so that the original |
836 | -- node is retained, in order to avoid the warning for | |
837 | -- redundant conversions in Resolve_Type_Conversion. | |
838 | ||
839 | Rewrite (N, Relocate_Node (N)); | |
840 | ||
f40f9731 | 841 | Set_Etype (N, Target_Type); |
780bfb21 | 842 | |
f40f9731 | 843 | Analyze_And_Resolve (Left_Opnd (N), Target_Type); |
844 | Analyze_And_Resolve (Right_Opnd (N), Target_Type); | |
845 | ||
846 | -- Given that the target type is twice the size of the | |
847 | -- source type, overflow is now impossible, so we can | |
848 | -- safely kill the overflow check and return. | |
849 | ||
850 | Set_Do_Overflow_Check (N, False); | |
851 | return; | |
852 | end if; | |
853 | end if; | |
854 | end if; | |
855 | end; | |
ee6ba406 | 856 | end if; |
857 | ||
f40f9731 | 858 | -- Now see if an overflow check is required |
859 | ||
860 | declare | |
861 | Siz : constant Int := UI_To_Int (Esize (Rtyp)); | |
862 | Dsiz : constant Int := Siz * 2; | |
863 | Opnod : Node_Id; | |
864 | Ctyp : Entity_Id; | |
865 | Opnd : Node_Id; | |
866 | Cent : RE_Id; | |
ee6ba406 | 867 | |
f40f9731 | 868 | begin |
869 | -- Skip check if back end does overflow checks, or the overflow flag | |
df40eeb0 | 870 | -- is not set anyway, or we are not doing code expansion, or the |
871 | -- parent node is a type conversion whose operand is an arithmetic | |
872 | -- operation on signed integers on which the expander can promote | |
bbbed24b | 873 | -- later the operands to type Integer (see Expand_N_Type_Conversion). |
ee6ba406 | 874 | |
f40f9731 | 875 | -- Special case CLI target, where arithmetic overflow checks can be |
876 | -- performed for integer and long_integer | |
ee6ba406 | 877 | |
f40f9731 | 878 | if Backend_Overflow_Checks_On_Target |
879 | or else not Do_Overflow_Check (N) | |
880 | or else not Expander_Active | |
df40eeb0 | 881 | or else (Present (Parent (N)) |
882 | and then Nkind (Parent (N)) = N_Type_Conversion | |
883 | and then Integer_Promotion_Possible (Parent (N))) | |
f40f9731 | 884 | or else |
885 | (VM_Target = CLI_Target and then Siz >= Standard_Integer_Size) | |
886 | then | |
887 | return; | |
888 | end if; | |
ee6ba406 | 889 | |
f40f9731 | 890 | -- Otherwise, generate the full general code for front end overflow |
891 | -- detection, which works by doing arithmetic in a larger type: | |
ee6ba406 | 892 | |
f40f9731 | 893 | -- x op y |
ee6ba406 | 894 | |
f40f9731 | 895 | -- is expanded into |
ee6ba406 | 896 | |
f40f9731 | 897 | -- Typ (Checktyp (x) op Checktyp (y)); |
ee6ba406 | 898 | |
f40f9731 | 899 | -- where Typ is the type of the original expression, and Checktyp is |
900 | -- an integer type of sufficient length to hold the largest possible | |
901 | -- result. | |
ee6ba406 | 902 | |
f40f9731 | 903 | -- If the size of check type exceeds the size of Long_Long_Integer, |
904 | -- we use a different approach, expanding to: | |
ee6ba406 | 905 | |
f40f9731 | 906 | -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y))) |
ee6ba406 | 907 | |
f40f9731 | 908 | -- where xxx is Add, Multiply or Subtract as appropriate |
ee6ba406 | 909 | |
f40f9731 | 910 | -- Find check type if one exists |
911 | ||
912 | if Dsiz <= Standard_Integer_Size then | |
913 | Ctyp := Standard_Integer; | |
ee6ba406 | 914 | |
f40f9731 | 915 | elsif Dsiz <= Standard_Long_Long_Integer_Size then |
916 | Ctyp := Standard_Long_Long_Integer; | |
917 | ||
918 | -- No check type exists, use runtime call | |
ee6ba406 | 919 | |
920 | else | |
f40f9731 | 921 | if Nkind (N) = N_Op_Add then |
922 | Cent := RE_Add_With_Ovflo_Check; | |
ee6ba406 | 923 | |
f40f9731 | 924 | elsif Nkind (N) = N_Op_Multiply then |
925 | Cent := RE_Multiply_With_Ovflo_Check; | |
ee6ba406 | 926 | |
f40f9731 | 927 | else |
928 | pragma Assert (Nkind (N) = N_Op_Subtract); | |
929 | Cent := RE_Subtract_With_Ovflo_Check; | |
930 | end if; | |
931 | ||
932 | Rewrite (N, | |
933 | OK_Convert_To (Typ, | |
934 | Make_Function_Call (Loc, | |
935 | Name => New_Reference_To (RTE (Cent), Loc), | |
936 | Parameter_Associations => New_List ( | |
937 | OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)), | |
938 | OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N)))))); | |
ee6ba406 | 939 | |
f40f9731 | 940 | Analyze_And_Resolve (N, Typ); |
941 | return; | |
942 | end if; | |
ee6ba406 | 943 | |
f40f9731 | 944 | -- If we fall through, we have the case where we do the arithmetic |
945 | -- in the next higher type and get the check by conversion. In these | |
946 | -- cases Ctyp is set to the type to be used as the check type. | |
ee6ba406 | 947 | |
f40f9731 | 948 | Opnod := Relocate_Node (N); |
ee6ba406 | 949 | |
f40f9731 | 950 | Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod)); |
ee6ba406 | 951 | |
f40f9731 | 952 | Analyze (Opnd); |
953 | Set_Etype (Opnd, Ctyp); | |
954 | Set_Analyzed (Opnd, True); | |
955 | Set_Left_Opnd (Opnod, Opnd); | |
ee6ba406 | 956 | |
f40f9731 | 957 | Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod)); |
ee6ba406 | 958 | |
f40f9731 | 959 | Analyze (Opnd); |
960 | Set_Etype (Opnd, Ctyp); | |
961 | Set_Analyzed (Opnd, True); | |
962 | Set_Right_Opnd (Opnod, Opnd); | |
ee6ba406 | 963 | |
f40f9731 | 964 | -- The type of the operation changes to the base type of the check |
965 | -- type, and we reset the overflow check indication, since clearly no | |
966 | -- overflow is possible now that we are using a double length type. | |
967 | -- We also set the Analyzed flag to avoid a recursive attempt to | |
968 | -- expand the node. | |
ee6ba406 | 969 | |
f40f9731 | 970 | Set_Etype (Opnod, Base_Type (Ctyp)); |
971 | Set_Do_Overflow_Check (Opnod, False); | |
972 | Set_Analyzed (Opnod, True); | |
ee6ba406 | 973 | |
f40f9731 | 974 | -- Now build the outer conversion |
ee6ba406 | 975 | |
f40f9731 | 976 | Opnd := OK_Convert_To (Typ, Opnod); |
977 | Analyze (Opnd); | |
978 | Set_Etype (Opnd, Typ); | |
9dfe12ae | 979 | |
f40f9731 | 980 | -- In the discrete type case, we directly generate the range check |
981 | -- for the outer operand. This range check will implement the | |
982 | -- required overflow check. | |
9dfe12ae | 983 | |
f40f9731 | 984 | if Is_Discrete_Type (Typ) then |
985 | Rewrite (N, Opnd); | |
986 | Generate_Range_Check | |
987 | (Expression (N), Typ, CE_Overflow_Check_Failed); | |
9dfe12ae | 988 | |
f40f9731 | 989 | -- For other types, we enable overflow checking on the conversion, |
990 | -- after setting the node as analyzed to prevent recursive attempts | |
991 | -- to expand the conversion node. | |
9dfe12ae | 992 | |
f40f9731 | 993 | else |
994 | Set_Analyzed (Opnd, True); | |
995 | Enable_Overflow_Check (Opnd); | |
996 | Rewrite (N, Opnd); | |
997 | end if; | |
998 | ||
999 | exception | |
1000 | when RE_Not_Available => | |
1001 | return; | |
1002 | end; | |
ee6ba406 | 1003 | end Apply_Arithmetic_Overflow_Check; |
1004 | ||
ee6ba406 | 1005 | ---------------------------- |
1006 | -- Apply_Constraint_Check -- | |
1007 | ---------------------------- | |
1008 | ||
1009 | procedure Apply_Constraint_Check | |
1010 | (N : Node_Id; | |
1011 | Typ : Entity_Id; | |
1012 | No_Sliding : Boolean := False) | |
1013 | is | |
1014 | Desig_Typ : Entity_Id; | |
1015 | ||
1016 | begin | |
7aafae1c | 1017 | -- No checks inside a generic (check the instantiations) |
1018 | ||
ee6ba406 | 1019 | if Inside_A_Generic then |
1020 | return; | |
7aafae1c | 1021 | end if; |
ee6ba406 | 1022 | |
6fb3c314 | 1023 | -- Apply required constraint checks |
7aafae1c | 1024 | |
1025 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 1026 | Apply_Scalar_Range_Check (N, Typ); |
1027 | ||
1028 | elsif Is_Array_Type (Typ) then | |
1029 | ||
05fcfafb | 1030 | -- A useful optimization: an aggregate with only an others clause |
5f260d20 | 1031 | -- always has the right bounds. |
1032 | ||
1033 | if Nkind (N) = N_Aggregate | |
1034 | and then No (Expressions (N)) | |
1035 | and then Nkind | |
1036 | (First (Choices (First (Component_Associations (N))))) | |
1037 | = N_Others_Choice | |
1038 | then | |
1039 | return; | |
1040 | end if; | |
1041 | ||
ee6ba406 | 1042 | if Is_Constrained (Typ) then |
1043 | Apply_Length_Check (N, Typ); | |
1044 | ||
1045 | if No_Sliding then | |
1046 | Apply_Range_Check (N, Typ); | |
1047 | end if; | |
1048 | else | |
1049 | Apply_Range_Check (N, Typ); | |
1050 | end if; | |
1051 | ||
1052 | elsif (Is_Record_Type (Typ) | |
1053 | or else Is_Private_Type (Typ)) | |
1054 | and then Has_Discriminants (Base_Type (Typ)) | |
1055 | and then Is_Constrained (Typ) | |
1056 | then | |
1057 | Apply_Discriminant_Check (N, Typ); | |
1058 | ||
1059 | elsif Is_Access_Type (Typ) then | |
1060 | ||
1061 | Desig_Typ := Designated_Type (Typ); | |
1062 | ||
1063 | -- No checks necessary if expression statically null | |
1064 | ||
2af58f67 | 1065 | if Known_Null (N) then |
00c403ee | 1066 | if Can_Never_Be_Null (Typ) then |
1067 | Install_Null_Excluding_Check (N); | |
1068 | end if; | |
ee6ba406 | 1069 | |
1070 | -- No sliding possible on access to arrays | |
1071 | ||
1072 | elsif Is_Array_Type (Desig_Typ) then | |
1073 | if Is_Constrained (Desig_Typ) then | |
1074 | Apply_Length_Check (N, Typ); | |
1075 | end if; | |
1076 | ||
1077 | Apply_Range_Check (N, Typ); | |
1078 | ||
1079 | elsif Has_Discriminants (Base_Type (Desig_Typ)) | |
1080 | and then Is_Constrained (Desig_Typ) | |
1081 | then | |
1082 | Apply_Discriminant_Check (N, Typ); | |
1083 | end if; | |
fa7497e8 | 1084 | |
bf3e1520 | 1085 | -- Apply the 2005 Null_Excluding check. Note that we do not apply |
00c403ee | 1086 | -- this check if the constraint node is illegal, as shown by having |
1087 | -- an error posted. This additional guard prevents cascaded errors | |
1088 | -- and compiler aborts on illegal programs involving Ada 2005 checks. | |
1089 | ||
fa7497e8 | 1090 | if Can_Never_Be_Null (Typ) |
1091 | and then not Can_Never_Be_Null (Etype (N)) | |
00c403ee | 1092 | and then not Error_Posted (N) |
fa7497e8 | 1093 | then |
1094 | Install_Null_Excluding_Check (N); | |
1095 | end if; | |
ee6ba406 | 1096 | end if; |
1097 | end Apply_Constraint_Check; | |
1098 | ||
1099 | ------------------------------ | |
1100 | -- Apply_Discriminant_Check -- | |
1101 | ------------------------------ | |
1102 | ||
1103 | procedure Apply_Discriminant_Check | |
1104 | (N : Node_Id; | |
1105 | Typ : Entity_Id; | |
1106 | Lhs : Node_Id := Empty) | |
1107 | is | |
1108 | Loc : constant Source_Ptr := Sloc (N); | |
1109 | Do_Access : constant Boolean := Is_Access_Type (Typ); | |
1110 | S_Typ : Entity_Id := Etype (N); | |
1111 | Cond : Node_Id; | |
1112 | T_Typ : Entity_Id; | |
1113 | ||
7be5088a | 1114 | function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean; |
1115 | -- A heap object with an indefinite subtype is constrained by its | |
1116 | -- initial value, and assigning to it requires a constraint_check. | |
1117 | -- The target may be an explicit dereference, or a renaming of one. | |
1118 | ||
ee6ba406 | 1119 | function Is_Aliased_Unconstrained_Component return Boolean; |
1120 | -- It is possible for an aliased component to have a nominal | |
1121 | -- unconstrained subtype (through instantiation). If this is a | |
1122 | -- discriminated component assigned in the expansion of an aggregate | |
1123 | -- in an initialization, the check must be suppressed. This unusual | |
2af58f67 | 1124 | -- situation requires a predicate of its own. |
ee6ba406 | 1125 | |
7be5088a | 1126 | ---------------------------------- |
1127 | -- Denotes_Explicit_Dereference -- | |
1128 | ---------------------------------- | |
1129 | ||
1130 | function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean is | |
1131 | begin | |
1132 | return | |
1133 | Nkind (Obj) = N_Explicit_Dereference | |
1134 | or else | |
1135 | (Is_Entity_Name (Obj) | |
1136 | and then Present (Renamed_Object (Entity (Obj))) | |
9474aa9c | 1137 | and then Nkind (Renamed_Object (Entity (Obj))) = |
1138 | N_Explicit_Dereference); | |
7be5088a | 1139 | end Denotes_Explicit_Dereference; |
1140 | ||
ee6ba406 | 1141 | ---------------------------------------- |
1142 | -- Is_Aliased_Unconstrained_Component -- | |
1143 | ---------------------------------------- | |
1144 | ||
1145 | function Is_Aliased_Unconstrained_Component return Boolean is | |
1146 | Comp : Entity_Id; | |
1147 | Pref : Node_Id; | |
1148 | ||
1149 | begin | |
1150 | if Nkind (Lhs) /= N_Selected_Component then | |
1151 | return False; | |
1152 | else | |
1153 | Comp := Entity (Selector_Name (Lhs)); | |
1154 | Pref := Prefix (Lhs); | |
1155 | end if; | |
1156 | ||
1157 | if Ekind (Comp) /= E_Component | |
1158 | or else not Is_Aliased (Comp) | |
1159 | then | |
1160 | return False; | |
1161 | end if; | |
1162 | ||
1163 | return not Comes_From_Source (Pref) | |
1164 | and then In_Instance | |
1165 | and then not Is_Constrained (Etype (Comp)); | |
1166 | end Is_Aliased_Unconstrained_Component; | |
1167 | ||
1168 | -- Start of processing for Apply_Discriminant_Check | |
1169 | ||
1170 | begin | |
1171 | if Do_Access then | |
1172 | T_Typ := Designated_Type (Typ); | |
1173 | else | |
1174 | T_Typ := Typ; | |
1175 | end if; | |
1176 | ||
1177 | -- Nothing to do if discriminant checks are suppressed or else no code | |
1178 | -- is to be generated | |
1179 | ||
1180 | if not Expander_Active | |
1181 | or else Discriminant_Checks_Suppressed (T_Typ) | |
1182 | then | |
1183 | return; | |
1184 | end if; | |
1185 | ||
feff2f05 | 1186 | -- No discriminant checks necessary for an access when expression is |
1187 | -- statically Null. This is not only an optimization, it is fundamental | |
1188 | -- because otherwise discriminant checks may be generated in init procs | |
1189 | -- for types containing an access to a not-yet-frozen record, causing a | |
1190 | -- deadly forward reference. | |
ee6ba406 | 1191 | |
feff2f05 | 1192 | -- Also, if the expression is of an access type whose designated type is |
1193 | -- incomplete, then the access value must be null and we suppress the | |
1194 | -- check. | |
ee6ba406 | 1195 | |
2af58f67 | 1196 | if Known_Null (N) then |
ee6ba406 | 1197 | return; |
1198 | ||
1199 | elsif Is_Access_Type (S_Typ) then | |
1200 | S_Typ := Designated_Type (S_Typ); | |
1201 | ||
1202 | if Ekind (S_Typ) = E_Incomplete_Type then | |
1203 | return; | |
1204 | end if; | |
1205 | end if; | |
1206 | ||
0577b0b1 | 1207 | -- If an assignment target is present, then we need to generate the |
1208 | -- actual subtype if the target is a parameter or aliased object with | |
1209 | -- an unconstrained nominal subtype. | |
1210 | ||
1211 | -- Ada 2005 (AI-363): For Ada 2005, we limit the building of the actual | |
1212 | -- subtype to the parameter and dereference cases, since other aliased | |
1213 | -- objects are unconstrained (unless the nominal subtype is explicitly | |
7be5088a | 1214 | -- constrained). |
ee6ba406 | 1215 | |
1216 | if Present (Lhs) | |
1217 | and then (Present (Param_Entity (Lhs)) | |
de54c5ab | 1218 | or else (Ada_Version < Ada_2005 |
0577b0b1 | 1219 | and then not Is_Constrained (T_Typ) |
ee6ba406 | 1220 | and then Is_Aliased_View (Lhs) |
0577b0b1 | 1221 | and then not Is_Aliased_Unconstrained_Component) |
de54c5ab | 1222 | or else (Ada_Version >= Ada_2005 |
0577b0b1 | 1223 | and then not Is_Constrained (T_Typ) |
7be5088a | 1224 | and then Denotes_Explicit_Dereference (Lhs) |
0577b0b1 | 1225 | and then Nkind (Original_Node (Lhs)) /= |
1226 | N_Function_Call)) | |
ee6ba406 | 1227 | then |
1228 | T_Typ := Get_Actual_Subtype (Lhs); | |
1229 | end if; | |
1230 | ||
feff2f05 | 1231 | -- Nothing to do if the type is unconstrained (this is the case where |
1232 | -- the actual subtype in the RM sense of N is unconstrained and no check | |
1233 | -- is required). | |
ee6ba406 | 1234 | |
1235 | if not Is_Constrained (T_Typ) then | |
1236 | return; | |
05fcfafb | 1237 | |
1238 | -- Ada 2005: nothing to do if the type is one for which there is a | |
1239 | -- partial view that is constrained. | |
1240 | ||
de54c5ab | 1241 | elsif Ada_Version >= Ada_2005 |
05fcfafb | 1242 | and then Has_Constrained_Partial_View (Base_Type (T_Typ)) |
1243 | then | |
1244 | return; | |
ee6ba406 | 1245 | end if; |
1246 | ||
00f91aef | 1247 | -- Nothing to do if the type is an Unchecked_Union |
1248 | ||
1249 | if Is_Unchecked_Union (Base_Type (T_Typ)) then | |
1250 | return; | |
1251 | end if; | |
1252 | ||
feff2f05 | 1253 | -- Suppress checks if the subtypes are the same. the check must be |
1254 | -- preserved in an assignment to a formal, because the constraint is | |
1255 | -- given by the actual. | |
ee6ba406 | 1256 | |
1257 | if Nkind (Original_Node (N)) /= N_Allocator | |
1258 | and then (No (Lhs) | |
1259 | or else not Is_Entity_Name (Lhs) | |
9dfe12ae | 1260 | or else No (Param_Entity (Lhs))) |
ee6ba406 | 1261 | then |
1262 | if (Etype (N) = Typ | |
1263 | or else (Do_Access and then Designated_Type (Typ) = S_Typ)) | |
1264 | and then not Is_Aliased_View (Lhs) | |
1265 | then | |
1266 | return; | |
1267 | end if; | |
1268 | ||
feff2f05 | 1269 | -- We can also eliminate checks on allocators with a subtype mark that |
1270 | -- coincides with the context type. The context type may be a subtype | |
1271 | -- without a constraint (common case, a generic actual). | |
ee6ba406 | 1272 | |
1273 | elsif Nkind (Original_Node (N)) = N_Allocator | |
1274 | and then Is_Entity_Name (Expression (Original_Node (N))) | |
1275 | then | |
1276 | declare | |
9dfe12ae | 1277 | Alloc_Typ : constant Entity_Id := |
1278 | Entity (Expression (Original_Node (N))); | |
ee6ba406 | 1279 | |
1280 | begin | |
1281 | if Alloc_Typ = T_Typ | |
1282 | or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration | |
1283 | and then Is_Entity_Name ( | |
1284 | Subtype_Indication (Parent (T_Typ))) | |
1285 | and then Alloc_Typ = Base_Type (T_Typ)) | |
1286 | ||
1287 | then | |
1288 | return; | |
1289 | end if; | |
1290 | end; | |
1291 | end if; | |
1292 | ||
feff2f05 | 1293 | -- See if we have a case where the types are both constrained, and all |
1294 | -- the constraints are constants. In this case, we can do the check | |
1295 | -- successfully at compile time. | |
ee6ba406 | 1296 | |
9dfe12ae | 1297 | -- We skip this check for the case where the node is a rewritten` |
ee6ba406 | 1298 | -- allocator, because it already carries the context subtype, and |
1299 | -- extracting the discriminants from the aggregate is messy. | |
1300 | ||
1301 | if Is_Constrained (S_Typ) | |
1302 | and then Nkind (Original_Node (N)) /= N_Allocator | |
1303 | then | |
1304 | declare | |
1305 | DconT : Elmt_Id; | |
1306 | Discr : Entity_Id; | |
1307 | DconS : Elmt_Id; | |
1308 | ItemS : Node_Id; | |
1309 | ItemT : Node_Id; | |
1310 | ||
1311 | begin | |
1312 | -- S_Typ may not have discriminants in the case where it is a | |
feff2f05 | 1313 | -- private type completed by a default discriminated type. In that |
1314 | -- case, we need to get the constraints from the underlying_type. | |
1315 | -- If the underlying type is unconstrained (i.e. has no default | |
1316 | -- discriminants) no check is needed. | |
ee6ba406 | 1317 | |
1318 | if Has_Discriminants (S_Typ) then | |
1319 | Discr := First_Discriminant (S_Typ); | |
1320 | DconS := First_Elmt (Discriminant_Constraint (S_Typ)); | |
1321 | ||
1322 | else | |
1323 | Discr := First_Discriminant (Underlying_Type (S_Typ)); | |
1324 | DconS := | |
1325 | First_Elmt | |
1326 | (Discriminant_Constraint (Underlying_Type (S_Typ))); | |
1327 | ||
1328 | if No (DconS) then | |
1329 | return; | |
1330 | end if; | |
fccb5da7 | 1331 | |
1332 | -- A further optimization: if T_Typ is derived from S_Typ | |
1333 | -- without imposing a constraint, no check is needed. | |
1334 | ||
1335 | if Nkind (Original_Node (Parent (T_Typ))) = | |
1336 | N_Full_Type_Declaration | |
1337 | then | |
1338 | declare | |
5c61a0ff | 1339 | Type_Def : constant Node_Id := |
fccb5da7 | 1340 | Type_Definition |
1341 | (Original_Node (Parent (T_Typ))); | |
1342 | begin | |
1343 | if Nkind (Type_Def) = N_Derived_Type_Definition | |
1344 | and then Is_Entity_Name (Subtype_Indication (Type_Def)) | |
1345 | and then Entity (Subtype_Indication (Type_Def)) = S_Typ | |
1346 | then | |
1347 | return; | |
1348 | end if; | |
1349 | end; | |
1350 | end if; | |
ee6ba406 | 1351 | end if; |
1352 | ||
1353 | DconT := First_Elmt (Discriminant_Constraint (T_Typ)); | |
1354 | ||
1355 | while Present (Discr) loop | |
1356 | ItemS := Node (DconS); | |
1357 | ItemT := Node (DconT); | |
1358 | ||
00c403ee | 1359 | -- For a discriminated component type constrained by the |
1360 | -- current instance of an enclosing type, there is no | |
1361 | -- applicable discriminant check. | |
1362 | ||
1363 | if Nkind (ItemT) = N_Attribute_Reference | |
1364 | and then Is_Access_Type (Etype (ItemT)) | |
1365 | and then Is_Entity_Name (Prefix (ItemT)) | |
1366 | and then Is_Type (Entity (Prefix (ItemT))) | |
1367 | then | |
1368 | return; | |
1369 | end if; | |
1370 | ||
cc60bd16 | 1371 | -- If the expressions for the discriminants are identical |
1372 | -- and it is side-effect free (for now just an entity), | |
1373 | -- this may be a shared constraint, e.g. from a subtype | |
1374 | -- without a constraint introduced as a generic actual. | |
1375 | -- Examine other discriminants if any. | |
1376 | ||
1377 | if ItemS = ItemT | |
1378 | and then Is_Entity_Name (ItemS) | |
1379 | then | |
1380 | null; | |
1381 | ||
1382 | elsif not Is_OK_Static_Expression (ItemS) | |
1383 | or else not Is_OK_Static_Expression (ItemT) | |
1384 | then | |
1385 | exit; | |
ee6ba406 | 1386 | |
cc60bd16 | 1387 | elsif Expr_Value (ItemS) /= Expr_Value (ItemT) then |
ee6ba406 | 1388 | if Do_Access then -- needs run-time check. |
1389 | exit; | |
1390 | else | |
1391 | Apply_Compile_Time_Constraint_Error | |
f15731c4 | 1392 | (N, "incorrect value for discriminant&?", |
1393 | CE_Discriminant_Check_Failed, Ent => Discr); | |
ee6ba406 | 1394 | return; |
1395 | end if; | |
1396 | end if; | |
1397 | ||
1398 | Next_Elmt (DconS); | |
1399 | Next_Elmt (DconT); | |
1400 | Next_Discriminant (Discr); | |
1401 | end loop; | |
1402 | ||
1403 | if No (Discr) then | |
1404 | return; | |
1405 | end if; | |
1406 | end; | |
1407 | end if; | |
1408 | ||
1409 | -- Here we need a discriminant check. First build the expression | |
1410 | -- for the comparisons of the discriminants: | |
1411 | ||
1412 | -- (n.disc1 /= typ.disc1) or else | |
1413 | -- (n.disc2 /= typ.disc2) or else | |
1414 | -- ... | |
1415 | -- (n.discn /= typ.discn) | |
1416 | ||
1417 | Cond := Build_Discriminant_Checks (N, T_Typ); | |
1418 | ||
1419 | -- If Lhs is set and is a parameter, then the condition is | |
1420 | -- guarded by: lhs'constrained and then (condition built above) | |
1421 | ||
1422 | if Present (Param_Entity (Lhs)) then | |
1423 | Cond := | |
1424 | Make_And_Then (Loc, | |
1425 | Left_Opnd => | |
1426 | Make_Attribute_Reference (Loc, | |
1427 | Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc), | |
1428 | Attribute_Name => Name_Constrained), | |
1429 | Right_Opnd => Cond); | |
1430 | end if; | |
1431 | ||
1432 | if Do_Access then | |
1433 | Cond := Guard_Access (Cond, Loc, N); | |
1434 | end if; | |
1435 | ||
1436 | Insert_Action (N, | |
f15731c4 | 1437 | Make_Raise_Constraint_Error (Loc, |
1438 | Condition => Cond, | |
1439 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 1440 | end Apply_Discriminant_Check; |
1441 | ||
1442 | ------------------------ | |
1443 | -- Apply_Divide_Check -- | |
1444 | ------------------------ | |
1445 | ||
1446 | procedure Apply_Divide_Check (N : Node_Id) is | |
1447 | Loc : constant Source_Ptr := Sloc (N); | |
1448 | Typ : constant Entity_Id := Etype (N); | |
1449 | Left : constant Node_Id := Left_Opnd (N); | |
1450 | Right : constant Node_Id := Right_Opnd (N); | |
1451 | ||
1452 | LLB : Uint; | |
1453 | Llo : Uint; | |
1454 | Lhi : Uint; | |
1455 | LOK : Boolean; | |
1456 | Rlo : Uint; | |
1457 | Rhi : Uint; | |
96da3284 | 1458 | ROK : Boolean; |
1459 | ||
1460 | pragma Warnings (Off, Lhi); | |
1461 | -- Don't actually use this value | |
ee6ba406 | 1462 | |
1463 | begin | |
1464 | if Expander_Active | |
13dbf220 | 1465 | and then not Backend_Divide_Checks_On_Target |
1466 | and then Check_Needed (Right, Division_Check) | |
ee6ba406 | 1467 | then |
9c486805 | 1468 | Determine_Range (Right, ROK, Rlo, Rhi, Assume_Valid => True); |
ee6ba406 | 1469 | |
1470 | -- See if division by zero possible, and if so generate test. This | |
1471 | -- part of the test is not controlled by the -gnato switch. | |
1472 | ||
1473 | if Do_Division_Check (N) then | |
ee6ba406 | 1474 | if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then |
1475 | Insert_Action (N, | |
1476 | Make_Raise_Constraint_Error (Loc, | |
1477 | Condition => | |
1478 | Make_Op_Eq (Loc, | |
0577b0b1 | 1479 | Left_Opnd => Duplicate_Subexpr_Move_Checks (Right), |
f15731c4 | 1480 | Right_Opnd => Make_Integer_Literal (Loc, 0)), |
1481 | Reason => CE_Divide_By_Zero)); | |
ee6ba406 | 1482 | end if; |
1483 | end if; | |
1484 | ||
1485 | -- Test for extremely annoying case of xxx'First divided by -1 | |
1486 | ||
1487 | if Do_Overflow_Check (N) then | |
ee6ba406 | 1488 | if Nkind (N) = N_Op_Divide |
1489 | and then Is_Signed_Integer_Type (Typ) | |
1490 | then | |
9c486805 | 1491 | Determine_Range (Left, LOK, Llo, Lhi, Assume_Valid => True); |
ee6ba406 | 1492 | LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ))); |
1493 | ||
1494 | if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) | |
1495 | and then | |
1496 | ((not LOK) or else (Llo = LLB)) | |
1497 | then | |
1498 | Insert_Action (N, | |
1499 | Make_Raise_Constraint_Error (Loc, | |
1500 | Condition => | |
1501 | Make_And_Then (Loc, | |
1502 | ||
1503 | Make_Op_Eq (Loc, | |
9dfe12ae | 1504 | Left_Opnd => |
1505 | Duplicate_Subexpr_Move_Checks (Left), | |
ee6ba406 | 1506 | Right_Opnd => Make_Integer_Literal (Loc, LLB)), |
1507 | ||
1508 | Make_Op_Eq (Loc, | |
9dfe12ae | 1509 | Left_Opnd => |
1510 | Duplicate_Subexpr (Right), | |
ee6ba406 | 1511 | Right_Opnd => |
f15731c4 | 1512 | Make_Integer_Literal (Loc, -1))), |
1513 | Reason => CE_Overflow_Check_Failed)); | |
ee6ba406 | 1514 | end if; |
1515 | end if; | |
1516 | end if; | |
1517 | end if; | |
1518 | end Apply_Divide_Check; | |
1519 | ||
5329ca64 | 1520 | ---------------------------------- |
1521 | -- Apply_Float_Conversion_Check -- | |
1522 | ---------------------------------- | |
1523 | ||
feff2f05 | 1524 | -- Let F and I be the source and target types of the conversion. The RM |
1525 | -- specifies that a floating-point value X is rounded to the nearest | |
1526 | -- integer, with halfway cases being rounded away from zero. The rounded | |
1527 | -- value of X is checked against I'Range. | |
1528 | ||
1529 | -- The catch in the above paragraph is that there is no good way to know | |
1530 | -- whether the round-to-integer operation resulted in overflow. A remedy is | |
1531 | -- to perform a range check in the floating-point domain instead, however: | |
5329ca64 | 1532 | |
5329ca64 | 1533 | -- (1) The bounds may not be known at compile time |
2af58f67 | 1534 | -- (2) The check must take into account rounding or truncation. |
5329ca64 | 1535 | -- (3) The range of type I may not be exactly representable in F. |
2af58f67 | 1536 | -- (4) For the rounding case, The end-points I'First - 0.5 and |
1537 | -- I'Last + 0.5 may or may not be in range, depending on the | |
1538 | -- sign of I'First and I'Last. | |
5329ca64 | 1539 | -- (5) X may be a NaN, which will fail any comparison |
1540 | ||
2af58f67 | 1541 | -- The following steps correctly convert X with rounding: |
feff2f05 | 1542 | |
5329ca64 | 1543 | -- (1) If either I'First or I'Last is not known at compile time, use |
1544 | -- I'Base instead of I in the next three steps and perform a | |
1545 | -- regular range check against I'Range after conversion. | |
1546 | -- (2) If I'First - 0.5 is representable in F then let Lo be that | |
1547 | -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be | |
2af58f67 | 1548 | -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First). |
1549 | -- In other words, take one of the closest floating-point numbers | |
1550 | -- (which is an integer value) to I'First, and see if it is in | |
1551 | -- range or not. | |
5329ca64 | 1552 | -- (3) If I'Last + 0.5 is representable in F then let Hi be that value |
1553 | -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be | |
2af58f67 | 1554 | -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last). |
5329ca64 | 1555 | -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo) |
1556 | -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi) | |
1557 | ||
2af58f67 | 1558 | -- For the truncating case, replace steps (2) and (3) as follows: |
1559 | -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK | |
1560 | -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let | |
1561 | -- Lo_OK be True. | |
1562 | -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK | |
1563 | -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let | |
141d591a | 1564 | -- Hi_OK be True. |
2af58f67 | 1565 | |
5329ca64 | 1566 | procedure Apply_Float_Conversion_Check |
1567 | (Ck_Node : Node_Id; | |
1568 | Target_Typ : Entity_Id) | |
1569 | is | |
feff2f05 | 1570 | LB : constant Node_Id := Type_Low_Bound (Target_Typ); |
1571 | HB : constant Node_Id := Type_High_Bound (Target_Typ); | |
5329ca64 | 1572 | Loc : constant Source_Ptr := Sloc (Ck_Node); |
1573 | Expr_Type : constant Entity_Id := Base_Type (Etype (Ck_Node)); | |
feff2f05 | 1574 | Target_Base : constant Entity_Id := |
1575 | Implementation_Base_Type (Target_Typ); | |
1576 | ||
2af58f67 | 1577 | Par : constant Node_Id := Parent (Ck_Node); |
1578 | pragma Assert (Nkind (Par) = N_Type_Conversion); | |
1579 | -- Parent of check node, must be a type conversion | |
1580 | ||
1581 | Truncate : constant Boolean := Float_Truncate (Par); | |
1582 | Max_Bound : constant Uint := | |
1583 | UI_Expon | |
e8548746 | 1584 | (Machine_Radix_Value (Expr_Type), |
1585 | Machine_Mantissa_Value (Expr_Type) - 1) - 1; | |
2af58f67 | 1586 | |
5329ca64 | 1587 | -- Largest bound, so bound plus or minus half is a machine number of F |
1588 | ||
feff2f05 | 1589 | Ifirst, Ilast : Uint; |
1590 | -- Bounds of integer type | |
1591 | ||
1592 | Lo, Hi : Ureal; | |
1593 | -- Bounds to check in floating-point domain | |
5329ca64 | 1594 | |
feff2f05 | 1595 | Lo_OK, Hi_OK : Boolean; |
1596 | -- True iff Lo resp. Hi belongs to I'Range | |
5329ca64 | 1597 | |
feff2f05 | 1598 | Lo_Chk, Hi_Chk : Node_Id; |
1599 | -- Expressions that are False iff check fails | |
1600 | ||
1601 | Reason : RT_Exception_Code; | |
5329ca64 | 1602 | |
1603 | begin | |
1604 | if not Compile_Time_Known_Value (LB) | |
1605 | or not Compile_Time_Known_Value (HB) | |
1606 | then | |
1607 | declare | |
feff2f05 | 1608 | -- First check that the value falls in the range of the base type, |
1609 | -- to prevent overflow during conversion and then perform a | |
1610 | -- regular range check against the (dynamic) bounds. | |
5329ca64 | 1611 | |
5329ca64 | 1612 | pragma Assert (Target_Base /= Target_Typ); |
5329ca64 | 1613 | |
46eb6933 | 1614 | Temp : constant Entity_Id := Make_Temporary (Loc, 'T', Par); |
5329ca64 | 1615 | |
1616 | begin | |
1617 | Apply_Float_Conversion_Check (Ck_Node, Target_Base); | |
1618 | Set_Etype (Temp, Target_Base); | |
1619 | ||
1620 | Insert_Action (Parent (Par), | |
1621 | Make_Object_Declaration (Loc, | |
1622 | Defining_Identifier => Temp, | |
1623 | Object_Definition => New_Occurrence_Of (Target_Typ, Loc), | |
1624 | Expression => New_Copy_Tree (Par)), | |
1625 | Suppress => All_Checks); | |
1626 | ||
1627 | Insert_Action (Par, | |
1628 | Make_Raise_Constraint_Error (Loc, | |
1629 | Condition => | |
1630 | Make_Not_In (Loc, | |
1631 | Left_Opnd => New_Occurrence_Of (Temp, Loc), | |
1632 | Right_Opnd => New_Occurrence_Of (Target_Typ, Loc)), | |
1633 | Reason => CE_Range_Check_Failed)); | |
1634 | Rewrite (Par, New_Occurrence_Of (Temp, Loc)); | |
1635 | ||
1636 | return; | |
1637 | end; | |
1638 | end if; | |
1639 | ||
7d86aa98 | 1640 | -- Get the (static) bounds of the target type |
5329ca64 | 1641 | |
1642 | Ifirst := Expr_Value (LB); | |
1643 | Ilast := Expr_Value (HB); | |
1644 | ||
7d86aa98 | 1645 | -- A simple optimization: if the expression is a universal literal, |
1646 | -- we can do the comparison with the bounds and the conversion to | |
1647 | -- an integer type statically. The range checks are unchanged. | |
1648 | ||
1649 | if Nkind (Ck_Node) = N_Real_Literal | |
1650 | and then Etype (Ck_Node) = Universal_Real | |
1651 | and then Is_Integer_Type (Target_Typ) | |
1652 | and then Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
1653 | then | |
1654 | declare | |
1655 | Int_Val : constant Uint := UR_To_Uint (Realval (Ck_Node)); | |
1656 | ||
1657 | begin | |
1658 | if Int_Val <= Ilast and then Int_Val >= Ifirst then | |
1659 | ||
4309515d | 1660 | -- Conversion is safe |
7d86aa98 | 1661 | |
1662 | Rewrite (Parent (Ck_Node), | |
1663 | Make_Integer_Literal (Loc, UI_To_Int (Int_Val))); | |
1664 | Analyze_And_Resolve (Parent (Ck_Node), Target_Typ); | |
1665 | return; | |
1666 | end if; | |
1667 | end; | |
1668 | end if; | |
1669 | ||
5329ca64 | 1670 | -- Check against lower bound |
1671 | ||
2af58f67 | 1672 | if Truncate and then Ifirst > 0 then |
1673 | Lo := Pred (Expr_Type, UR_From_Uint (Ifirst)); | |
1674 | Lo_OK := False; | |
1675 | ||
1676 | elsif Truncate then | |
1677 | Lo := Succ (Expr_Type, UR_From_Uint (Ifirst - 1)); | |
1678 | Lo_OK := True; | |
1679 | ||
1680 | elsif abs (Ifirst) < Max_Bound then | |
5329ca64 | 1681 | Lo := UR_From_Uint (Ifirst) - Ureal_Half; |
1682 | Lo_OK := (Ifirst > 0); | |
2af58f67 | 1683 | |
5329ca64 | 1684 | else |
1685 | Lo := Machine (Expr_Type, UR_From_Uint (Ifirst), Round_Even, Ck_Node); | |
1686 | Lo_OK := (Lo >= UR_From_Uint (Ifirst)); | |
1687 | end if; | |
1688 | ||
1689 | if Lo_OK then | |
1690 | ||
1691 | -- Lo_Chk := (X >= Lo) | |
1692 | ||
1693 | Lo_Chk := Make_Op_Ge (Loc, | |
1694 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1695 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
1696 | ||
1697 | else | |
1698 | -- Lo_Chk := (X > Lo) | |
1699 | ||
1700 | Lo_Chk := Make_Op_Gt (Loc, | |
1701 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1702 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
1703 | end if; | |
1704 | ||
1705 | -- Check against higher bound | |
1706 | ||
2af58f67 | 1707 | if Truncate and then Ilast < 0 then |
1708 | Hi := Succ (Expr_Type, UR_From_Uint (Ilast)); | |
b2c42753 | 1709 | Hi_OK := False; |
2af58f67 | 1710 | |
1711 | elsif Truncate then | |
1712 | Hi := Pred (Expr_Type, UR_From_Uint (Ilast + 1)); | |
1713 | Hi_OK := True; | |
1714 | ||
1715 | elsif abs (Ilast) < Max_Bound then | |
5329ca64 | 1716 | Hi := UR_From_Uint (Ilast) + Ureal_Half; |
1717 | Hi_OK := (Ilast < 0); | |
1718 | else | |
1719 | Hi := Machine (Expr_Type, UR_From_Uint (Ilast), Round_Even, Ck_Node); | |
1720 | Hi_OK := (Hi <= UR_From_Uint (Ilast)); | |
1721 | end if; | |
1722 | ||
1723 | if Hi_OK then | |
1724 | ||
1725 | -- Hi_Chk := (X <= Hi) | |
1726 | ||
1727 | Hi_Chk := Make_Op_Le (Loc, | |
1728 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1729 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
1730 | ||
1731 | else | |
1732 | -- Hi_Chk := (X < Hi) | |
1733 | ||
1734 | Hi_Chk := Make_Op_Lt (Loc, | |
1735 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
1736 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
1737 | end if; | |
1738 | ||
feff2f05 | 1739 | -- If the bounds of the target type are the same as those of the base |
1740 | -- type, the check is an overflow check as a range check is not | |
1741 | -- performed in these cases. | |
5329ca64 | 1742 | |
1743 | if Expr_Value (Type_Low_Bound (Target_Base)) = Ifirst | |
1744 | and then Expr_Value (Type_High_Bound (Target_Base)) = Ilast | |
1745 | then | |
1746 | Reason := CE_Overflow_Check_Failed; | |
1747 | else | |
1748 | Reason := CE_Range_Check_Failed; | |
1749 | end if; | |
1750 | ||
1751 | -- Raise CE if either conditions does not hold | |
1752 | ||
1753 | Insert_Action (Ck_Node, | |
1754 | Make_Raise_Constraint_Error (Loc, | |
05fcfafb | 1755 | Condition => Make_Op_Not (Loc, Make_And_Then (Loc, Lo_Chk, Hi_Chk)), |
5329ca64 | 1756 | Reason => Reason)); |
1757 | end Apply_Float_Conversion_Check; | |
1758 | ||
ee6ba406 | 1759 | ------------------------ |
1760 | -- Apply_Length_Check -- | |
1761 | ------------------------ | |
1762 | ||
1763 | procedure Apply_Length_Check | |
1764 | (Ck_Node : Node_Id; | |
1765 | Target_Typ : Entity_Id; | |
1766 | Source_Typ : Entity_Id := Empty) | |
1767 | is | |
1768 | begin | |
1769 | Apply_Selected_Length_Checks | |
1770 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
1771 | end Apply_Length_Check; | |
1772 | ||
7aafae1c | 1773 | --------------------------- |
1774 | -- Apply_Predicate_Check -- | |
1775 | --------------------------- | |
1776 | ||
1777 | procedure Apply_Predicate_Check (N : Node_Id; Typ : Entity_Id) is | |
1778 | begin | |
701d57a4 | 1779 | if Present (Predicate_Function (Typ)) then |
7aafae1c | 1780 | Insert_Action (N, |
1781 | Make_Predicate_Check (Typ, Duplicate_Subexpr (N))); | |
1782 | end if; | |
1783 | end Apply_Predicate_Check; | |
1784 | ||
ee6ba406 | 1785 | ----------------------- |
1786 | -- Apply_Range_Check -- | |
1787 | ----------------------- | |
1788 | ||
1789 | procedure Apply_Range_Check | |
1790 | (Ck_Node : Node_Id; | |
1791 | Target_Typ : Entity_Id; | |
1792 | Source_Typ : Entity_Id := Empty) | |
1793 | is | |
1794 | begin | |
1795 | Apply_Selected_Range_Checks | |
1796 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
1797 | end Apply_Range_Check; | |
1798 | ||
1799 | ------------------------------ | |
1800 | -- Apply_Scalar_Range_Check -- | |
1801 | ------------------------------ | |
1802 | ||
feff2f05 | 1803 | -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag |
1804 | -- off if it is already set on. | |
ee6ba406 | 1805 | |
1806 | procedure Apply_Scalar_Range_Check | |
1807 | (Expr : Node_Id; | |
1808 | Target_Typ : Entity_Id; | |
1809 | Source_Typ : Entity_Id := Empty; | |
1810 | Fixed_Int : Boolean := False) | |
1811 | is | |
1812 | Parnt : constant Node_Id := Parent (Expr); | |
1813 | S_Typ : Entity_Id; | |
1814 | Arr : Node_Id := Empty; -- initialize to prevent warning | |
1815 | Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning | |
1816 | OK : Boolean; | |
1817 | ||
1818 | Is_Subscr_Ref : Boolean; | |
1819 | -- Set true if Expr is a subscript | |
1820 | ||
1821 | Is_Unconstrained_Subscr_Ref : Boolean; | |
1822 | -- Set true if Expr is a subscript of an unconstrained array. In this | |
1823 | -- case we do not attempt to do an analysis of the value against the | |
1824 | -- range of the subscript, since we don't know the actual subtype. | |
1825 | ||
1826 | Int_Real : Boolean; | |
feff2f05 | 1827 | -- Set to True if Expr should be regarded as a real value even though |
1828 | -- the type of Expr might be discrete. | |
ee6ba406 | 1829 | |
1830 | procedure Bad_Value; | |
1831 | -- Procedure called if value is determined to be out of range | |
1832 | ||
9dfe12ae | 1833 | --------------- |
1834 | -- Bad_Value -- | |
1835 | --------------- | |
1836 | ||
ee6ba406 | 1837 | procedure Bad_Value is |
1838 | begin | |
1839 | Apply_Compile_Time_Constraint_Error | |
f15731c4 | 1840 | (Expr, "value not in range of}?", CE_Range_Check_Failed, |
ee6ba406 | 1841 | Ent => Target_Typ, |
1842 | Typ => Target_Typ); | |
1843 | end Bad_Value; | |
1844 | ||
9dfe12ae | 1845 | -- Start of processing for Apply_Scalar_Range_Check |
1846 | ||
ee6ba406 | 1847 | begin |
2af58f67 | 1848 | -- Return if check obviously not needed |
ee6ba406 | 1849 | |
2af58f67 | 1850 | if |
1851 | -- Not needed inside generic | |
ee6ba406 | 1852 | |
2af58f67 | 1853 | Inside_A_Generic |
1854 | ||
1855 | -- Not needed if previous error | |
1856 | ||
1857 | or else Target_Typ = Any_Type | |
1858 | or else Nkind (Expr) = N_Error | |
1859 | ||
1860 | -- Not needed for non-scalar type | |
1861 | ||
1862 | or else not Is_Scalar_Type (Target_Typ) | |
1863 | ||
1864 | -- Not needed if we know node raises CE already | |
1865 | ||
1866 | or else Raises_Constraint_Error (Expr) | |
ee6ba406 | 1867 | then |
1868 | return; | |
1869 | end if; | |
1870 | ||
1871 | -- Now, see if checks are suppressed | |
1872 | ||
1873 | Is_Subscr_Ref := | |
1874 | Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component; | |
1875 | ||
1876 | if Is_Subscr_Ref then | |
1877 | Arr := Prefix (Parnt); | |
1878 | Arr_Typ := Get_Actual_Subtype_If_Available (Arr); | |
1879 | end if; | |
1880 | ||
1881 | if not Do_Range_Check (Expr) then | |
1882 | ||
1883 | -- Subscript reference. Check for Index_Checks suppressed | |
1884 | ||
1885 | if Is_Subscr_Ref then | |
1886 | ||
1887 | -- Check array type and its base type | |
1888 | ||
1889 | if Index_Checks_Suppressed (Arr_Typ) | |
9dfe12ae | 1890 | or else Index_Checks_Suppressed (Base_Type (Arr_Typ)) |
ee6ba406 | 1891 | then |
1892 | return; | |
1893 | ||
1894 | -- Check array itself if it is an entity name | |
1895 | ||
1896 | elsif Is_Entity_Name (Arr) | |
9dfe12ae | 1897 | and then Index_Checks_Suppressed (Entity (Arr)) |
ee6ba406 | 1898 | then |
1899 | return; | |
1900 | ||
1901 | -- Check expression itself if it is an entity name | |
1902 | ||
1903 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 1904 | and then Index_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 1905 | then |
1906 | return; | |
1907 | end if; | |
1908 | ||
1909 | -- All other cases, check for Range_Checks suppressed | |
1910 | ||
1911 | else | |
1912 | -- Check target type and its base type | |
1913 | ||
1914 | if Range_Checks_Suppressed (Target_Typ) | |
9dfe12ae | 1915 | or else Range_Checks_Suppressed (Base_Type (Target_Typ)) |
ee6ba406 | 1916 | then |
1917 | return; | |
1918 | ||
1919 | -- Check expression itself if it is an entity name | |
1920 | ||
1921 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 1922 | and then Range_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 1923 | then |
1924 | return; | |
1925 | ||
feff2f05 | 1926 | -- If Expr is part of an assignment statement, then check left |
1927 | -- side of assignment if it is an entity name. | |
ee6ba406 | 1928 | |
1929 | elsif Nkind (Parnt) = N_Assignment_Statement | |
1930 | and then Is_Entity_Name (Name (Parnt)) | |
9dfe12ae | 1931 | and then Range_Checks_Suppressed (Entity (Name (Parnt))) |
ee6ba406 | 1932 | then |
1933 | return; | |
1934 | end if; | |
1935 | end if; | |
1936 | end if; | |
1937 | ||
9dfe12ae | 1938 | -- Do not set range checks if they are killed |
1939 | ||
1940 | if Nkind (Expr) = N_Unchecked_Type_Conversion | |
1941 | and then Kill_Range_Check (Expr) | |
1942 | then | |
1943 | return; | |
1944 | end if; | |
1945 | ||
1946 | -- Do not set range checks for any values from System.Scalar_Values | |
1947 | -- since the whole idea of such values is to avoid checking them! | |
1948 | ||
1949 | if Is_Entity_Name (Expr) | |
1950 | and then Is_RTU (Scope (Entity (Expr)), System_Scalar_Values) | |
1951 | then | |
1952 | return; | |
1953 | end if; | |
1954 | ||
ee6ba406 | 1955 | -- Now see if we need a check |
1956 | ||
1957 | if No (Source_Typ) then | |
1958 | S_Typ := Etype (Expr); | |
1959 | else | |
1960 | S_Typ := Source_Typ; | |
1961 | end if; | |
1962 | ||
1963 | if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then | |
1964 | return; | |
1965 | end if; | |
1966 | ||
1967 | Is_Unconstrained_Subscr_Ref := | |
1968 | Is_Subscr_Ref and then not Is_Constrained (Arr_Typ); | |
1969 | ||
feff2f05 | 1970 | -- Always do a range check if the source type includes infinities and |
1971 | -- the target type does not include infinities. We do not do this if | |
1972 | -- range checks are killed. | |
ee6ba406 | 1973 | |
1974 | if Is_Floating_Point_Type (S_Typ) | |
1975 | and then Has_Infinities (S_Typ) | |
1976 | and then not Has_Infinities (Target_Typ) | |
1977 | then | |
1978 | Enable_Range_Check (Expr); | |
1979 | end if; | |
1980 | ||
feff2f05 | 1981 | -- Return if we know expression is definitely in the range of the target |
1982 | -- type as determined by Determine_Range. Right now we only do this for | |
1983 | -- discrete types, and not fixed-point or floating-point types. | |
ee6ba406 | 1984 | |
f2a06be9 | 1985 | -- The additional less-precise tests below catch these cases |
ee6ba406 | 1986 | |
feff2f05 | 1987 | -- Note: skip this if we are given a source_typ, since the point of |
1988 | -- supplying a Source_Typ is to stop us looking at the expression. | |
1989 | -- We could sharpen this test to be out parameters only ??? | |
ee6ba406 | 1990 | |
1991 | if Is_Discrete_Type (Target_Typ) | |
1992 | and then Is_Discrete_Type (Etype (Expr)) | |
1993 | and then not Is_Unconstrained_Subscr_Ref | |
1994 | and then No (Source_Typ) | |
1995 | then | |
1996 | declare | |
1997 | Tlo : constant Node_Id := Type_Low_Bound (Target_Typ); | |
1998 | Thi : constant Node_Id := Type_High_Bound (Target_Typ); | |
1999 | Lo : Uint; | |
2000 | Hi : Uint; | |
2001 | ||
2002 | begin | |
2003 | if Compile_Time_Known_Value (Tlo) | |
2004 | and then Compile_Time_Known_Value (Thi) | |
2005 | then | |
9dfe12ae | 2006 | declare |
2007 | Lov : constant Uint := Expr_Value (Tlo); | |
2008 | Hiv : constant Uint := Expr_Value (Thi); | |
ee6ba406 | 2009 | |
9dfe12ae | 2010 | begin |
2011 | -- If range is null, we for sure have a constraint error | |
2012 | -- (we don't even need to look at the value involved, | |
2013 | -- since all possible values will raise CE). | |
2014 | ||
2015 | if Lov > Hiv then | |
2016 | Bad_Value; | |
2017 | return; | |
2018 | end if; | |
2019 | ||
2020 | -- Otherwise determine range of value | |
2021 | ||
9c486805 | 2022 | Determine_Range (Expr, OK, Lo, Hi, Assume_Valid => True); |
9dfe12ae | 2023 | |
2024 | if OK then | |
2025 | ||
2026 | -- If definitely in range, all OK | |
ee6ba406 | 2027 | |
ee6ba406 | 2028 | if Lo >= Lov and then Hi <= Hiv then |
2029 | return; | |
2030 | ||
9dfe12ae | 2031 | -- If definitely not in range, warn |
2032 | ||
ee6ba406 | 2033 | elsif Lov > Hi or else Hiv < Lo then |
2034 | Bad_Value; | |
2035 | return; | |
9dfe12ae | 2036 | |
2037 | -- Otherwise we don't know | |
2038 | ||
2039 | else | |
2040 | null; | |
ee6ba406 | 2041 | end if; |
9dfe12ae | 2042 | end if; |
2043 | end; | |
ee6ba406 | 2044 | end if; |
2045 | end; | |
2046 | end if; | |
2047 | ||
2048 | Int_Real := | |
2049 | Is_Floating_Point_Type (S_Typ) | |
2050 | or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int); | |
2051 | ||
2052 | -- Check if we can determine at compile time whether Expr is in the | |
9dfe12ae | 2053 | -- range of the target type. Note that if S_Typ is within the bounds |
2054 | -- of Target_Typ then this must be the case. This check is meaningful | |
2055 | -- only if this is not a conversion between integer and real types. | |
ee6ba406 | 2056 | |
2057 | if not Is_Unconstrained_Subscr_Ref | |
2058 | and then | |
2059 | Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ) | |
2060 | and then | |
7a1dabb3 | 2061 | (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int) |
ee6ba406 | 2062 | or else |
9c486805 | 2063 | Is_In_Range (Expr, Target_Typ, |
2064 | Assume_Valid => True, | |
2065 | Fixed_Int => Fixed_Int, | |
2066 | Int_Real => Int_Real)) | |
ee6ba406 | 2067 | then |
2068 | return; | |
2069 | ||
9c486805 | 2070 | elsif Is_Out_Of_Range (Expr, Target_Typ, |
2071 | Assume_Valid => True, | |
2072 | Fixed_Int => Fixed_Int, | |
2073 | Int_Real => Int_Real) | |
2074 | then | |
ee6ba406 | 2075 | Bad_Value; |
2076 | return; | |
2077 | ||
feff2f05 | 2078 | -- In the floating-point case, we only do range checks if the type is |
2079 | -- constrained. We definitely do NOT want range checks for unconstrained | |
2080 | -- types, since we want to have infinities | |
ee6ba406 | 2081 | |
9dfe12ae | 2082 | elsif Is_Floating_Point_Type (S_Typ) then |
2083 | if Is_Constrained (S_Typ) then | |
2084 | Enable_Range_Check (Expr); | |
2085 | end if; | |
ee6ba406 | 2086 | |
9dfe12ae | 2087 | -- For all other cases we enable a range check unconditionally |
ee6ba406 | 2088 | |
2089 | else | |
2090 | Enable_Range_Check (Expr); | |
2091 | return; | |
2092 | end if; | |
ee6ba406 | 2093 | end Apply_Scalar_Range_Check; |
2094 | ||
2095 | ---------------------------------- | |
2096 | -- Apply_Selected_Length_Checks -- | |
2097 | ---------------------------------- | |
2098 | ||
2099 | procedure Apply_Selected_Length_Checks | |
2100 | (Ck_Node : Node_Id; | |
2101 | Target_Typ : Entity_Id; | |
2102 | Source_Typ : Entity_Id; | |
2103 | Do_Static : Boolean) | |
2104 | is | |
2105 | Cond : Node_Id; | |
2106 | R_Result : Check_Result; | |
2107 | R_Cno : Node_Id; | |
2108 | ||
2109 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
2110 | Checks_On : constant Boolean := | |
2111 | (not Index_Checks_Suppressed (Target_Typ)) | |
2112 | or else | |
2113 | (not Length_Checks_Suppressed (Target_Typ)); | |
2114 | ||
2115 | begin | |
f15731c4 | 2116 | if not Expander_Active then |
ee6ba406 | 2117 | return; |
2118 | end if; | |
2119 | ||
2120 | R_Result := | |
2121 | Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
2122 | ||
2123 | for J in 1 .. 2 loop | |
ee6ba406 | 2124 | R_Cno := R_Result (J); |
2125 | exit when No (R_Cno); | |
2126 | ||
2127 | -- A length check may mention an Itype which is attached to a | |
2128 | -- subsequent node. At the top level in a package this can cause | |
2129 | -- an order-of-elaboration problem, so we make sure that the itype | |
2130 | -- is referenced now. | |
2131 | ||
2132 | if Ekind (Current_Scope) = E_Package | |
2133 | and then Is_Compilation_Unit (Current_Scope) | |
2134 | then | |
2135 | Ensure_Defined (Target_Typ, Ck_Node); | |
2136 | ||
2137 | if Present (Source_Typ) then | |
2138 | Ensure_Defined (Source_Typ, Ck_Node); | |
2139 | ||
2140 | elsif Is_Itype (Etype (Ck_Node)) then | |
2141 | Ensure_Defined (Etype (Ck_Node), Ck_Node); | |
2142 | end if; | |
2143 | end if; | |
2144 | ||
feff2f05 | 2145 | -- If the item is a conditional raise of constraint error, then have |
2146 | -- a look at what check is being performed and ??? | |
ee6ba406 | 2147 | |
2148 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
2149 | and then Present (Condition (R_Cno)) | |
2150 | then | |
2151 | Cond := Condition (R_Cno); | |
2152 | ||
0577b0b1 | 2153 | -- Case where node does not now have a dynamic check |
ee6ba406 | 2154 | |
0577b0b1 | 2155 | if not Has_Dynamic_Length_Check (Ck_Node) then |
2156 | ||
2157 | -- If checks are on, just insert the check | |
2158 | ||
2159 | if Checks_On then | |
2160 | Insert_Action (Ck_Node, R_Cno); | |
2161 | ||
2162 | if not Do_Static then | |
2163 | Set_Has_Dynamic_Length_Check (Ck_Node); | |
2164 | end if; | |
2165 | ||
2166 | -- If checks are off, then analyze the length check after | |
2167 | -- temporarily attaching it to the tree in case the relevant | |
6fb3c314 | 2168 | -- condition can be evaluated at compile time. We still want a |
0577b0b1 | 2169 | -- compile time warning in this case. |
2170 | ||
2171 | else | |
2172 | Set_Parent (R_Cno, Ck_Node); | |
2173 | Analyze (R_Cno); | |
ee6ba406 | 2174 | end if; |
ee6ba406 | 2175 | end if; |
2176 | ||
2177 | -- Output a warning if the condition is known to be True | |
2178 | ||
2179 | if Is_Entity_Name (Cond) | |
2180 | and then Entity (Cond) = Standard_True | |
2181 | then | |
2182 | Apply_Compile_Time_Constraint_Error | |
2183 | (Ck_Node, "wrong length for array of}?", | |
f15731c4 | 2184 | CE_Length_Check_Failed, |
ee6ba406 | 2185 | Ent => Target_Typ, |
2186 | Typ => Target_Typ); | |
2187 | ||
2188 | -- If we were only doing a static check, or if checks are not | |
2189 | -- on, then we want to delete the check, since it is not needed. | |
2190 | -- We do this by replacing the if statement by a null statement | |
2191 | ||
2192 | elsif Do_Static or else not Checks_On then | |
00c403ee | 2193 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 2194 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
2195 | end if; | |
2196 | ||
2197 | else | |
2198 | Install_Static_Check (R_Cno, Loc); | |
2199 | end if; | |
ee6ba406 | 2200 | end loop; |
ee6ba406 | 2201 | end Apply_Selected_Length_Checks; |
2202 | ||
2203 | --------------------------------- | |
2204 | -- Apply_Selected_Range_Checks -- | |
2205 | --------------------------------- | |
2206 | ||
2207 | procedure Apply_Selected_Range_Checks | |
2208 | (Ck_Node : Node_Id; | |
2209 | Target_Typ : Entity_Id; | |
2210 | Source_Typ : Entity_Id; | |
2211 | Do_Static : Boolean) | |
2212 | is | |
2213 | Cond : Node_Id; | |
2214 | R_Result : Check_Result; | |
2215 | R_Cno : Node_Id; | |
2216 | ||
2217 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
2218 | Checks_On : constant Boolean := | |
2219 | (not Index_Checks_Suppressed (Target_Typ)) | |
2220 | or else | |
2221 | (not Range_Checks_Suppressed (Target_Typ)); | |
2222 | ||
2223 | begin | |
2224 | if not Expander_Active or else not Checks_On then | |
2225 | return; | |
2226 | end if; | |
2227 | ||
2228 | R_Result := | |
2229 | Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
2230 | ||
2231 | for J in 1 .. 2 loop | |
2232 | ||
2233 | R_Cno := R_Result (J); | |
2234 | exit when No (R_Cno); | |
2235 | ||
feff2f05 | 2236 | -- If the item is a conditional raise of constraint error, then have |
2237 | -- a look at what check is being performed and ??? | |
ee6ba406 | 2238 | |
2239 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
2240 | and then Present (Condition (R_Cno)) | |
2241 | then | |
2242 | Cond := Condition (R_Cno); | |
2243 | ||
2244 | if not Has_Dynamic_Range_Check (Ck_Node) then | |
2245 | Insert_Action (Ck_Node, R_Cno); | |
2246 | ||
2247 | if not Do_Static then | |
2248 | Set_Has_Dynamic_Range_Check (Ck_Node); | |
2249 | end if; | |
2250 | end if; | |
2251 | ||
2252 | -- Output a warning if the condition is known to be True | |
2253 | ||
2254 | if Is_Entity_Name (Cond) | |
2255 | and then Entity (Cond) = Standard_True | |
2256 | then | |
feff2f05 | 2257 | -- Since an N_Range is technically not an expression, we have |
2258 | -- to set one of the bounds to C_E and then just flag the | |
2259 | -- N_Range. The warning message will point to the lower bound | |
2260 | -- and complain about a range, which seems OK. | |
ee6ba406 | 2261 | |
2262 | if Nkind (Ck_Node) = N_Range then | |
2263 | Apply_Compile_Time_Constraint_Error | |
2264 | (Low_Bound (Ck_Node), "static range out of bounds of}?", | |
f15731c4 | 2265 | CE_Range_Check_Failed, |
ee6ba406 | 2266 | Ent => Target_Typ, |
2267 | Typ => Target_Typ); | |
2268 | ||
2269 | Set_Raises_Constraint_Error (Ck_Node); | |
2270 | ||
2271 | else | |
2272 | Apply_Compile_Time_Constraint_Error | |
2273 | (Ck_Node, "static value out of range of}?", | |
f15731c4 | 2274 | CE_Range_Check_Failed, |
ee6ba406 | 2275 | Ent => Target_Typ, |
2276 | Typ => Target_Typ); | |
2277 | end if; | |
2278 | ||
2279 | -- If we were only doing a static check, or if checks are not | |
2280 | -- on, then we want to delete the check, since it is not needed. | |
2281 | -- We do this by replacing the if statement by a null statement | |
2282 | ||
2283 | elsif Do_Static or else not Checks_On then | |
00c403ee | 2284 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 2285 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
2286 | end if; | |
2287 | ||
2288 | else | |
2289 | Install_Static_Check (R_Cno, Loc); | |
2290 | end if; | |
ee6ba406 | 2291 | end loop; |
ee6ba406 | 2292 | end Apply_Selected_Range_Checks; |
2293 | ||
2294 | ------------------------------- | |
2295 | -- Apply_Static_Length_Check -- | |
2296 | ------------------------------- | |
2297 | ||
2298 | procedure Apply_Static_Length_Check | |
2299 | (Expr : Node_Id; | |
2300 | Target_Typ : Entity_Id; | |
2301 | Source_Typ : Entity_Id := Empty) | |
2302 | is | |
2303 | begin | |
2304 | Apply_Selected_Length_Checks | |
2305 | (Expr, Target_Typ, Source_Typ, Do_Static => True); | |
2306 | end Apply_Static_Length_Check; | |
2307 | ||
2308 | ------------------------------------- | |
2309 | -- Apply_Subscript_Validity_Checks -- | |
2310 | ------------------------------------- | |
2311 | ||
2312 | procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is | |
2313 | Sub : Node_Id; | |
2314 | ||
2315 | begin | |
2316 | pragma Assert (Nkind (Expr) = N_Indexed_Component); | |
2317 | ||
2318 | -- Loop through subscripts | |
2319 | ||
2320 | Sub := First (Expressions (Expr)); | |
2321 | while Present (Sub) loop | |
2322 | ||
feff2f05 | 2323 | -- Check one subscript. Note that we do not worry about enumeration |
2324 | -- type with holes, since we will convert the value to a Pos value | |
2325 | -- for the subscript, and that convert will do the necessary validity | |
2326 | -- check. | |
ee6ba406 | 2327 | |
2328 | Ensure_Valid (Sub, Holes_OK => True); | |
2329 | ||
2330 | -- Move to next subscript | |
2331 | ||
2332 | Sub := Next (Sub); | |
2333 | end loop; | |
2334 | end Apply_Subscript_Validity_Checks; | |
2335 | ||
2336 | ---------------------------------- | |
2337 | -- Apply_Type_Conversion_Checks -- | |
2338 | ---------------------------------- | |
2339 | ||
2340 | procedure Apply_Type_Conversion_Checks (N : Node_Id) is | |
2341 | Target_Type : constant Entity_Id := Etype (N); | |
2342 | Target_Base : constant Entity_Id := Base_Type (Target_Type); | |
9dfe12ae | 2343 | Expr : constant Node_Id := Expression (N); |
f4532fe1 | 2344 | |
2345 | Expr_Type : constant Entity_Id := Underlying_Type (Etype (Expr)); | |
141d591a | 2346 | -- Note: if Etype (Expr) is a private type without discriminants, its |
2347 | -- full view might have discriminants with defaults, so we need the | |
2348 | -- full view here to retrieve the constraints. | |
ee6ba406 | 2349 | |
2350 | begin | |
2351 | if Inside_A_Generic then | |
2352 | return; | |
2353 | ||
f15731c4 | 2354 | -- Skip these checks if serious errors detected, there are some nasty |
ee6ba406 | 2355 | -- situations of incomplete trees that blow things up. |
2356 | ||
f15731c4 | 2357 | elsif Serious_Errors_Detected > 0 then |
ee6ba406 | 2358 | return; |
2359 | ||
feff2f05 | 2360 | -- Scalar type conversions of the form Target_Type (Expr) require a |
2361 | -- range check if we cannot be sure that Expr is in the base type of | |
2362 | -- Target_Typ and also that Expr is in the range of Target_Typ. These | |
2363 | -- are not quite the same condition from an implementation point of | |
2364 | -- view, but clearly the second includes the first. | |
ee6ba406 | 2365 | |
2366 | elsif Is_Scalar_Type (Target_Type) then | |
2367 | declare | |
2368 | Conv_OK : constant Boolean := Conversion_OK (N); | |
feff2f05 | 2369 | -- If the Conversion_OK flag on the type conversion is set and no |
2370 | -- floating point type is involved in the type conversion then | |
2371 | -- fixed point values must be read as integral values. | |
ee6ba406 | 2372 | |
5329ca64 | 2373 | Float_To_Int : constant Boolean := |
2374 | Is_Floating_Point_Type (Expr_Type) | |
2375 | and then Is_Integer_Type (Target_Type); | |
2376 | ||
ee6ba406 | 2377 | begin |
ee6ba406 | 2378 | if not Overflow_Checks_Suppressed (Target_Base) |
e254d721 | 2379 | and then not |
7a1dabb3 | 2380 | In_Subrange_Of (Expr_Type, Target_Base, Fixed_Int => Conv_OK) |
5329ca64 | 2381 | and then not Float_To_Int |
ee6ba406 | 2382 | then |
00c403ee | 2383 | Activate_Overflow_Check (N); |
ee6ba406 | 2384 | end if; |
2385 | ||
2386 | if not Range_Checks_Suppressed (Target_Type) | |
2387 | and then not Range_Checks_Suppressed (Expr_Type) | |
2388 | then | |
5329ca64 | 2389 | if Float_To_Int then |
2390 | Apply_Float_Conversion_Check (Expr, Target_Type); | |
2391 | else | |
2392 | Apply_Scalar_Range_Check | |
2393 | (Expr, Target_Type, Fixed_Int => Conv_OK); | |
2394 | end if; | |
ee6ba406 | 2395 | end if; |
2396 | end; | |
2397 | ||
2398 | elsif Comes_From_Source (N) | |
f40f9731 | 2399 | and then not Discriminant_Checks_Suppressed (Target_Type) |
ee6ba406 | 2400 | and then Is_Record_Type (Target_Type) |
2401 | and then Is_Derived_Type (Target_Type) | |
2402 | and then not Is_Tagged_Type (Target_Type) | |
2403 | and then not Is_Constrained (Target_Type) | |
9dfe12ae | 2404 | and then Present (Stored_Constraint (Target_Type)) |
ee6ba406 | 2405 | then |
141d591a | 2406 | -- An unconstrained derived type may have inherited discriminant. |
9dfe12ae | 2407 | -- Build an actual discriminant constraint list using the stored |
ee6ba406 | 2408 | -- constraint, to verify that the expression of the parent type |
2409 | -- satisfies the constraints imposed by the (unconstrained!) | |
2410 | -- derived type. This applies to value conversions, not to view | |
2411 | -- conversions of tagged types. | |
2412 | ||
2413 | declare | |
9dfe12ae | 2414 | Loc : constant Source_Ptr := Sloc (N); |
2415 | Cond : Node_Id; | |
2416 | Constraint : Elmt_Id; | |
2417 | Discr_Value : Node_Id; | |
2418 | Discr : Entity_Id; | |
2419 | ||
2420 | New_Constraints : constant Elist_Id := New_Elmt_List; | |
2421 | Old_Constraints : constant Elist_Id := | |
2422 | Discriminant_Constraint (Expr_Type); | |
ee6ba406 | 2423 | |
2424 | begin | |
9dfe12ae | 2425 | Constraint := First_Elmt (Stored_Constraint (Target_Type)); |
ee6ba406 | 2426 | while Present (Constraint) loop |
2427 | Discr_Value := Node (Constraint); | |
2428 | ||
2429 | if Is_Entity_Name (Discr_Value) | |
2430 | and then Ekind (Entity (Discr_Value)) = E_Discriminant | |
2431 | then | |
2432 | Discr := Corresponding_Discriminant (Entity (Discr_Value)); | |
2433 | ||
2434 | if Present (Discr) | |
2435 | and then Scope (Discr) = Base_Type (Expr_Type) | |
2436 | then | |
2437 | -- Parent is constrained by new discriminant. Obtain | |
feff2f05 | 2438 | -- Value of original discriminant in expression. If the |
2439 | -- new discriminant has been used to constrain more than | |
2440 | -- one of the stored discriminants, this will provide the | |
2441 | -- required consistency check. | |
ee6ba406 | 2442 | |
55868293 | 2443 | Append_Elmt |
2444 | (Make_Selected_Component (Loc, | |
2445 | Prefix => | |
9dfe12ae | 2446 | Duplicate_Subexpr_No_Checks |
2447 | (Expr, Name_Req => True), | |
ee6ba406 | 2448 | Selector_Name => |
2449 | Make_Identifier (Loc, Chars (Discr))), | |
55868293 | 2450 | New_Constraints); |
ee6ba406 | 2451 | |
2452 | else | |
2453 | -- Discriminant of more remote ancestor ??? | |
2454 | ||
2455 | return; | |
2456 | end if; | |
2457 | ||
feff2f05 | 2458 | -- Derived type definition has an explicit value for this |
2459 | -- stored discriminant. | |
ee6ba406 | 2460 | |
2461 | else | |
2462 | Append_Elmt | |
9dfe12ae | 2463 | (Duplicate_Subexpr_No_Checks (Discr_Value), |
2464 | New_Constraints); | |
ee6ba406 | 2465 | end if; |
2466 | ||
2467 | Next_Elmt (Constraint); | |
2468 | end loop; | |
2469 | ||
2470 | -- Use the unconstrained expression type to retrieve the | |
2471 | -- discriminants of the parent, and apply momentarily the | |
2472 | -- discriminant constraint synthesized above. | |
2473 | ||
2474 | Set_Discriminant_Constraint (Expr_Type, New_Constraints); | |
2475 | Cond := Build_Discriminant_Checks (Expr, Expr_Type); | |
2476 | Set_Discriminant_Constraint (Expr_Type, Old_Constraints); | |
2477 | ||
2478 | Insert_Action (N, | |
f15731c4 | 2479 | Make_Raise_Constraint_Error (Loc, |
2480 | Condition => Cond, | |
2481 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 2482 | end; |
2483 | ||
feff2f05 | 2484 | -- For arrays, conversions are applied during expansion, to take into |
2485 | -- accounts changes of representation. The checks become range checks on | |
2486 | -- the base type or length checks on the subtype, depending on whether | |
2487 | -- the target type is unconstrained or constrained. | |
ee6ba406 | 2488 | |
2489 | else | |
2490 | null; | |
2491 | end if; | |
ee6ba406 | 2492 | end Apply_Type_Conversion_Checks; |
2493 | ||
2494 | ---------------------------------------------- | |
2495 | -- Apply_Universal_Integer_Attribute_Checks -- | |
2496 | ---------------------------------------------- | |
2497 | ||
2498 | procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is | |
2499 | Loc : constant Source_Ptr := Sloc (N); | |
2500 | Typ : constant Entity_Id := Etype (N); | |
2501 | ||
2502 | begin | |
2503 | if Inside_A_Generic then | |
2504 | return; | |
2505 | ||
2506 | -- Nothing to do if checks are suppressed | |
2507 | ||
2508 | elsif Range_Checks_Suppressed (Typ) | |
2509 | and then Overflow_Checks_Suppressed (Typ) | |
2510 | then | |
2511 | return; | |
2512 | ||
2513 | -- Nothing to do if the attribute does not come from source. The | |
2514 | -- internal attributes we generate of this type do not need checks, | |
2515 | -- and furthermore the attempt to check them causes some circular | |
2516 | -- elaboration orders when dealing with packed types. | |
2517 | ||
2518 | elsif not Comes_From_Source (N) then | |
2519 | return; | |
2520 | ||
9dfe12ae | 2521 | -- If the prefix is a selected component that depends on a discriminant |
2522 | -- the check may improperly expose a discriminant instead of using | |
2523 | -- the bounds of the object itself. Set the type of the attribute to | |
2524 | -- the base type of the context, so that a check will be imposed when | |
2525 | -- needed (e.g. if the node appears as an index). | |
2526 | ||
2527 | elsif Nkind (Prefix (N)) = N_Selected_Component | |
2528 | and then Ekind (Typ) = E_Signed_Integer_Subtype | |
2529 | and then Depends_On_Discriminant (Scalar_Range (Typ)) | |
2530 | then | |
2531 | Set_Etype (N, Base_Type (Typ)); | |
2532 | ||
feff2f05 | 2533 | -- Otherwise, replace the attribute node with a type conversion node |
2534 | -- whose expression is the attribute, retyped to universal integer, and | |
2535 | -- whose subtype mark is the target type. The call to analyze this | |
2536 | -- conversion will set range and overflow checks as required for proper | |
2537 | -- detection of an out of range value. | |
ee6ba406 | 2538 | |
2539 | else | |
2540 | Set_Etype (N, Universal_Integer); | |
2541 | Set_Analyzed (N, True); | |
2542 | ||
2543 | Rewrite (N, | |
2544 | Make_Type_Conversion (Loc, | |
2545 | Subtype_Mark => New_Occurrence_Of (Typ, Loc), | |
2546 | Expression => Relocate_Node (N))); | |
2547 | ||
2548 | Analyze_And_Resolve (N, Typ); | |
2549 | return; | |
2550 | end if; | |
ee6ba406 | 2551 | end Apply_Universal_Integer_Attribute_Checks; |
2552 | ||
2553 | ------------------------------- | |
2554 | -- Build_Discriminant_Checks -- | |
2555 | ------------------------------- | |
2556 | ||
2557 | function Build_Discriminant_Checks | |
2558 | (N : Node_Id; | |
314a23b6 | 2559 | T_Typ : Entity_Id) return Node_Id |
ee6ba406 | 2560 | is |
2561 | Loc : constant Source_Ptr := Sloc (N); | |
2562 | Cond : Node_Id; | |
2563 | Disc : Elmt_Id; | |
2564 | Disc_Ent : Entity_Id; | |
9dfe12ae | 2565 | Dref : Node_Id; |
ee6ba406 | 2566 | Dval : Node_Id; |
2567 | ||
84d0d4a5 | 2568 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id; |
2569 | ||
2570 | ---------------------------------- | |
2571 | -- Aggregate_Discriminant_Value -- | |
2572 | ---------------------------------- | |
2573 | ||
2574 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id is | |
2575 | Assoc : Node_Id; | |
2576 | ||
2577 | begin | |
feff2f05 | 2578 | -- The aggregate has been normalized with named associations. We use |
2579 | -- the Chars field to locate the discriminant to take into account | |
2580 | -- discriminants in derived types, which carry the same name as those | |
2581 | -- in the parent. | |
84d0d4a5 | 2582 | |
2583 | Assoc := First (Component_Associations (N)); | |
2584 | while Present (Assoc) loop | |
2585 | if Chars (First (Choices (Assoc))) = Chars (Disc) then | |
2586 | return Expression (Assoc); | |
2587 | else | |
2588 | Next (Assoc); | |
2589 | end if; | |
2590 | end loop; | |
2591 | ||
2592 | -- Discriminant must have been found in the loop above | |
2593 | ||
2594 | raise Program_Error; | |
2595 | end Aggregate_Discriminant_Val; | |
2596 | ||
2597 | -- Start of processing for Build_Discriminant_Checks | |
2598 | ||
ee6ba406 | 2599 | begin |
84d0d4a5 | 2600 | -- Loop through discriminants evolving the condition |
2601 | ||
ee6ba406 | 2602 | Cond := Empty; |
2603 | Disc := First_Elmt (Discriminant_Constraint (T_Typ)); | |
2604 | ||
9dfe12ae | 2605 | -- For a fully private type, use the discriminants of the parent type |
ee6ba406 | 2606 | |
2607 | if Is_Private_Type (T_Typ) | |
2608 | and then No (Full_View (T_Typ)) | |
2609 | then | |
2610 | Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ))); | |
2611 | else | |
2612 | Disc_Ent := First_Discriminant (T_Typ); | |
2613 | end if; | |
2614 | ||
2615 | while Present (Disc) loop | |
ee6ba406 | 2616 | Dval := Node (Disc); |
2617 | ||
2618 | if Nkind (Dval) = N_Identifier | |
2619 | and then Ekind (Entity (Dval)) = E_Discriminant | |
2620 | then | |
2621 | Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc); | |
2622 | else | |
9dfe12ae | 2623 | Dval := Duplicate_Subexpr_No_Checks (Dval); |
ee6ba406 | 2624 | end if; |
2625 | ||
00f91aef | 2626 | -- If we have an Unchecked_Union node, we can infer the discriminants |
2627 | -- of the node. | |
9dfe12ae | 2628 | |
00f91aef | 2629 | if Is_Unchecked_Union (Base_Type (T_Typ)) then |
2630 | Dref := New_Copy ( | |
2631 | Get_Discriminant_Value ( | |
2632 | First_Discriminant (T_Typ), | |
2633 | T_Typ, | |
2634 | Stored_Constraint (T_Typ))); | |
2635 | ||
84d0d4a5 | 2636 | elsif Nkind (N) = N_Aggregate then |
2637 | Dref := | |
2638 | Duplicate_Subexpr_No_Checks | |
2639 | (Aggregate_Discriminant_Val (Disc_Ent)); | |
2640 | ||
00f91aef | 2641 | else |
2642 | Dref := | |
2643 | Make_Selected_Component (Loc, | |
2644 | Prefix => | |
2645 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), | |
2646 | Selector_Name => | |
2647 | Make_Identifier (Loc, Chars (Disc_Ent))); | |
2648 | ||
2649 | Set_Is_In_Discriminant_Check (Dref); | |
2650 | end if; | |
9dfe12ae | 2651 | |
ee6ba406 | 2652 | Evolve_Or_Else (Cond, |
2653 | Make_Op_Ne (Loc, | |
9dfe12ae | 2654 | Left_Opnd => Dref, |
ee6ba406 | 2655 | Right_Opnd => Dval)); |
2656 | ||
2657 | Next_Elmt (Disc); | |
2658 | Next_Discriminant (Disc_Ent); | |
2659 | end loop; | |
2660 | ||
2661 | return Cond; | |
2662 | end Build_Discriminant_Checks; | |
2663 | ||
13dbf220 | 2664 | ------------------ |
2665 | -- Check_Needed -- | |
2666 | ------------------ | |
2667 | ||
2668 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean is | |
2669 | N : Node_Id; | |
2670 | P : Node_Id; | |
2671 | K : Node_Kind; | |
2672 | L : Node_Id; | |
2673 | R : Node_Id; | |
2674 | ||
2675 | begin | |
2676 | -- Always check if not simple entity | |
2677 | ||
2678 | if Nkind (Nod) not in N_Has_Entity | |
2679 | or else not Comes_From_Source (Nod) | |
2680 | then | |
2681 | return True; | |
2682 | end if; | |
2683 | ||
2684 | -- Look up tree for short circuit | |
2685 | ||
2686 | N := Nod; | |
2687 | loop | |
2688 | P := Parent (N); | |
2689 | K := Nkind (P); | |
2690 | ||
7b17e51b | 2691 | -- Done if out of subexpression (note that we allow generated stuff |
2692 | -- such as itype declarations in this context, to keep the loop going | |
2693 | -- since we may well have generated such stuff in complex situations. | |
2694 | -- Also done if no parent (probably an error condition, but no point | |
2695 | -- in behaving nasty if we find it!) | |
2696 | ||
2697 | if No (P) | |
2698 | or else (K not in N_Subexpr and then Comes_From_Source (P)) | |
2699 | then | |
13dbf220 | 2700 | return True; |
2701 | ||
7b17e51b | 2702 | -- Or/Or Else case, where test is part of the right operand, or is |
2703 | -- part of one of the actions associated with the right operand, and | |
2704 | -- the left operand is an equality test. | |
13dbf220 | 2705 | |
7b17e51b | 2706 | elsif K = N_Op_Or then |
13dbf220 | 2707 | exit when N = Right_Opnd (P) |
2708 | and then Nkind (Left_Opnd (P)) = N_Op_Eq; | |
2709 | ||
7b17e51b | 2710 | elsif K = N_Or_Else then |
2711 | exit when (N = Right_Opnd (P) | |
2712 | or else | |
2713 | (Is_List_Member (N) | |
2714 | and then List_Containing (N) = Actions (P))) | |
2715 | and then Nkind (Left_Opnd (P)) = N_Op_Eq; | |
13dbf220 | 2716 | |
7b17e51b | 2717 | -- Similar test for the And/And then case, where the left operand |
2718 | -- is an inequality test. | |
2719 | ||
2720 | elsif K = N_Op_And then | |
13dbf220 | 2721 | exit when N = Right_Opnd (P) |
38f5559f | 2722 | and then Nkind (Left_Opnd (P)) = N_Op_Ne; |
7b17e51b | 2723 | |
2724 | elsif K = N_And_Then then | |
2725 | exit when (N = Right_Opnd (P) | |
2726 | or else | |
2727 | (Is_List_Member (N) | |
2728 | and then List_Containing (N) = Actions (P))) | |
2729 | and then Nkind (Left_Opnd (P)) = N_Op_Ne; | |
13dbf220 | 2730 | end if; |
2731 | ||
2732 | N := P; | |
2733 | end loop; | |
2734 | ||
2735 | -- If we fall through the loop, then we have a conditional with an | |
2736 | -- appropriate test as its left operand. So test further. | |
2737 | ||
2738 | L := Left_Opnd (P); | |
13dbf220 | 2739 | R := Right_Opnd (L); |
2740 | L := Left_Opnd (L); | |
2741 | ||
2742 | -- Left operand of test must match original variable | |
2743 | ||
2744 | if Nkind (L) not in N_Has_Entity | |
2745 | or else Entity (L) /= Entity (Nod) | |
2746 | then | |
2747 | return True; | |
2748 | end if; | |
2749 | ||
2af58f67 | 2750 | -- Right operand of test must be key value (zero or null) |
13dbf220 | 2751 | |
2752 | case Check is | |
2753 | when Access_Check => | |
2af58f67 | 2754 | if not Known_Null (R) then |
13dbf220 | 2755 | return True; |
2756 | end if; | |
2757 | ||
2758 | when Division_Check => | |
2759 | if not Compile_Time_Known_Value (R) | |
2760 | or else Expr_Value (R) /= Uint_0 | |
2761 | then | |
2762 | return True; | |
2763 | end if; | |
2af58f67 | 2764 | |
2765 | when others => | |
2766 | raise Program_Error; | |
13dbf220 | 2767 | end case; |
2768 | ||
2769 | -- Here we have the optimizable case, warn if not short-circuited | |
2770 | ||
2771 | if K = N_Op_And or else K = N_Op_Or then | |
2772 | case Check is | |
2773 | when Access_Check => | |
2774 | Error_Msg_N | |
2775 | ("Constraint_Error may be raised (access check)?", | |
2776 | Parent (Nod)); | |
2777 | when Division_Check => | |
2778 | Error_Msg_N | |
2779 | ("Constraint_Error may be raised (zero divide)?", | |
2780 | Parent (Nod)); | |
2af58f67 | 2781 | |
2782 | when others => | |
2783 | raise Program_Error; | |
13dbf220 | 2784 | end case; |
2785 | ||
2786 | if K = N_Op_And then | |
e977c0cf | 2787 | Error_Msg_N -- CODEFIX |
2788 | ("use `AND THEN` instead of AND?", P); | |
13dbf220 | 2789 | else |
e977c0cf | 2790 | Error_Msg_N -- CODEFIX |
2791 | ("use `OR ELSE` instead of OR?", P); | |
13dbf220 | 2792 | end if; |
2793 | ||
6fb3c314 | 2794 | -- If not short-circuited, we need the check |
13dbf220 | 2795 | |
2796 | return True; | |
2797 | ||
2798 | -- If short-circuited, we can omit the check | |
2799 | ||
2800 | else | |
2801 | return False; | |
2802 | end if; | |
2803 | end Check_Needed; | |
2804 | ||
ee6ba406 | 2805 | ----------------------------------- |
2806 | -- Check_Valid_Lvalue_Subscripts -- | |
2807 | ----------------------------------- | |
2808 | ||
2809 | procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is | |
2810 | begin | |
2811 | -- Skip this if range checks are suppressed | |
2812 | ||
2813 | if Range_Checks_Suppressed (Etype (Expr)) then | |
2814 | return; | |
2815 | ||
feff2f05 | 2816 | -- Only do this check for expressions that come from source. We assume |
2817 | -- that expander generated assignments explicitly include any necessary | |
2818 | -- checks. Note that this is not just an optimization, it avoids | |
2819 | -- infinite recursions! | |
ee6ba406 | 2820 | |
2821 | elsif not Comes_From_Source (Expr) then | |
2822 | return; | |
2823 | ||
2824 | -- For a selected component, check the prefix | |
2825 | ||
2826 | elsif Nkind (Expr) = N_Selected_Component then | |
2827 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
2828 | return; | |
2829 | ||
2830 | -- Case of indexed component | |
2831 | ||
2832 | elsif Nkind (Expr) = N_Indexed_Component then | |
2833 | Apply_Subscript_Validity_Checks (Expr); | |
2834 | ||
feff2f05 | 2835 | -- Prefix may itself be or contain an indexed component, and these |
2836 | -- subscripts need checking as well. | |
ee6ba406 | 2837 | |
2838 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
2839 | end if; | |
2840 | end Check_Valid_Lvalue_Subscripts; | |
2841 | ||
fa7497e8 | 2842 | ---------------------------------- |
2843 | -- Null_Exclusion_Static_Checks -- | |
2844 | ---------------------------------- | |
2845 | ||
2846 | procedure Null_Exclusion_Static_Checks (N : Node_Id) is | |
0577b0b1 | 2847 | Error_Node : Node_Id; |
2848 | Expr : Node_Id; | |
2849 | Has_Null : constant Boolean := Has_Null_Exclusion (N); | |
2850 | K : constant Node_Kind := Nkind (N); | |
2851 | Typ : Entity_Id; | |
fa7497e8 | 2852 | |
13dbf220 | 2853 | begin |
0577b0b1 | 2854 | pragma Assert |
2855 | (K = N_Component_Declaration | |
2856 | or else K = N_Discriminant_Specification | |
2857 | or else K = N_Function_Specification | |
2858 | or else K = N_Object_Declaration | |
2859 | or else K = N_Parameter_Specification); | |
2860 | ||
2861 | if K = N_Function_Specification then | |
2862 | Typ := Etype (Defining_Entity (N)); | |
2863 | else | |
2864 | Typ := Etype (Defining_Identifier (N)); | |
2865 | end if; | |
fa7497e8 | 2866 | |
13dbf220 | 2867 | case K is |
13dbf220 | 2868 | when N_Component_Declaration => |
2869 | if Present (Access_Definition (Component_Definition (N))) then | |
0577b0b1 | 2870 | Error_Node := Component_Definition (N); |
13dbf220 | 2871 | else |
0577b0b1 | 2872 | Error_Node := Subtype_Indication (Component_Definition (N)); |
13dbf220 | 2873 | end if; |
5329ca64 | 2874 | |
0577b0b1 | 2875 | when N_Discriminant_Specification => |
2876 | Error_Node := Discriminant_Type (N); | |
2877 | ||
2878 | when N_Function_Specification => | |
2879 | Error_Node := Result_Definition (N); | |
2880 | ||
2881 | when N_Object_Declaration => | |
2882 | Error_Node := Object_Definition (N); | |
2883 | ||
2884 | when N_Parameter_Specification => | |
2885 | Error_Node := Parameter_Type (N); | |
2886 | ||
13dbf220 | 2887 | when others => |
2888 | raise Program_Error; | |
2889 | end case; | |
5329ca64 | 2890 | |
0577b0b1 | 2891 | if Has_Null then |
5329ca64 | 2892 | |
0577b0b1 | 2893 | -- Enforce legality rule 3.10 (13): A null exclusion can only be |
2894 | -- applied to an access [sub]type. | |
5329ca64 | 2895 | |
0577b0b1 | 2896 | if not Is_Access_Type (Typ) then |
503f7fd3 | 2897 | Error_Msg_N |
00c403ee | 2898 | ("`NOT NULL` allowed only for an access type", Error_Node); |
5329ca64 | 2899 | |
feff2f05 | 2900 | -- Enforce legality rule RM 3.10(14/1): A null exclusion can only |
0577b0b1 | 2901 | -- be applied to a [sub]type that does not exclude null already. |
2902 | ||
2903 | elsif Can_Never_Be_Null (Typ) | |
d16989f1 | 2904 | and then Comes_From_Source (Typ) |
0577b0b1 | 2905 | then |
503f7fd3 | 2906 | Error_Msg_NE |
00c403ee | 2907 | ("`NOT NULL` not allowed (& already excludes null)", |
2908 | Error_Node, Typ); | |
0577b0b1 | 2909 | end if; |
13dbf220 | 2910 | end if; |
5329ca64 | 2911 | |
cc60bd16 | 2912 | -- Check that null-excluding objects are always initialized, except for |
2913 | -- deferred constants, for which the expression will appear in the full | |
2914 | -- declaration. | |
13dbf220 | 2915 | |
2916 | if K = N_Object_Declaration | |
84d0d4a5 | 2917 | and then No (Expression (N)) |
cc60bd16 | 2918 | and then not Constant_Present (N) |
feff2f05 | 2919 | and then not No_Initialization (N) |
13dbf220 | 2920 | then |
feff2f05 | 2921 | -- Add an expression that assigns null. This node is needed by |
2922 | -- Apply_Compile_Time_Constraint_Error, which will replace this with | |
2923 | -- a Constraint_Error node. | |
13dbf220 | 2924 | |
2925 | Set_Expression (N, Make_Null (Sloc (N))); | |
2926 | Set_Etype (Expression (N), Etype (Defining_Identifier (N))); | |
5329ca64 | 2927 | |
13dbf220 | 2928 | Apply_Compile_Time_Constraint_Error |
2929 | (N => Expression (N), | |
2930 | Msg => "(Ada 2005) null-excluding objects must be initialized?", | |
2931 | Reason => CE_Null_Not_Allowed); | |
2932 | end if; | |
5329ca64 | 2933 | |
cc60bd16 | 2934 | -- Check that a null-excluding component, formal or object is not being |
2935 | -- assigned a null value. Otherwise generate a warning message and | |
2c145f84 | 2936 | -- replace Expression (N) by an N_Constraint_Error node. |
13dbf220 | 2937 | |
0577b0b1 | 2938 | if K /= N_Function_Specification then |
2939 | Expr := Expression (N); | |
5329ca64 | 2940 | |
2af58f67 | 2941 | if Present (Expr) and then Known_Null (Expr) then |
13dbf220 | 2942 | case K is |
0577b0b1 | 2943 | when N_Component_Declaration | |
2944 | N_Discriminant_Specification => | |
7189d17f | 2945 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 2946 | (N => Expr, |
2af58f67 | 2947 | Msg => "(Ada 2005) null not allowed " & |
0577b0b1 | 2948 | "in null-excluding components?", |
2949 | Reason => CE_Null_Not_Allowed); | |
5329ca64 | 2950 | |
0577b0b1 | 2951 | when N_Object_Declaration => |
7189d17f | 2952 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 2953 | (N => Expr, |
2af58f67 | 2954 | Msg => "(Ada 2005) null not allowed " & |
0577b0b1 | 2955 | "in null-excluding objects?", |
2956 | Reason => CE_Null_Not_Allowed); | |
5329ca64 | 2957 | |
0577b0b1 | 2958 | when N_Parameter_Specification => |
7189d17f | 2959 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 2960 | (N => Expr, |
2af58f67 | 2961 | Msg => "(Ada 2005) null not allowed " & |
0577b0b1 | 2962 | "in null-excluding formals?", |
2963 | Reason => CE_Null_Not_Allowed); | |
13dbf220 | 2964 | |
2965 | when others => | |
2966 | null; | |
5329ca64 | 2967 | end case; |
2968 | end if; | |
0577b0b1 | 2969 | end if; |
fa7497e8 | 2970 | end Null_Exclusion_Static_Checks; |
2971 | ||
9dfe12ae | 2972 | ---------------------------------- |
2973 | -- Conditional_Statements_Begin -- | |
2974 | ---------------------------------- | |
2975 | ||
2976 | procedure Conditional_Statements_Begin is | |
2977 | begin | |
2978 | Saved_Checks_TOS := Saved_Checks_TOS + 1; | |
2979 | ||
feff2f05 | 2980 | -- If stack overflows, kill all checks, that way we know to simply reset |
2981 | -- the number of saved checks to zero on return. This should never occur | |
2982 | -- in practice. | |
9dfe12ae | 2983 | |
2984 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
2985 | Kill_All_Checks; | |
2986 | ||
feff2f05 | 2987 | -- In the normal case, we just make a new stack entry saving the current |
2988 | -- number of saved checks for a later restore. | |
9dfe12ae | 2989 | |
2990 | else | |
2991 | Saved_Checks_Stack (Saved_Checks_TOS) := Num_Saved_Checks; | |
2992 | ||
2993 | if Debug_Flag_CC then | |
2994 | w ("Conditional_Statements_Begin: Num_Saved_Checks = ", | |
2995 | Num_Saved_Checks); | |
2996 | end if; | |
2997 | end if; | |
2998 | end Conditional_Statements_Begin; | |
2999 | ||
3000 | -------------------------------- | |
3001 | -- Conditional_Statements_End -- | |
3002 | -------------------------------- | |
3003 | ||
3004 | procedure Conditional_Statements_End is | |
3005 | begin | |
3006 | pragma Assert (Saved_Checks_TOS > 0); | |
3007 | ||
feff2f05 | 3008 | -- If the saved checks stack overflowed, then we killed all checks, so |
3009 | -- setting the number of saved checks back to zero is correct. This | |
3010 | -- should never occur in practice. | |
9dfe12ae | 3011 | |
3012 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
3013 | Num_Saved_Checks := 0; | |
3014 | ||
feff2f05 | 3015 | -- In the normal case, restore the number of saved checks from the top |
3016 | -- stack entry. | |
9dfe12ae | 3017 | |
3018 | else | |
3019 | Num_Saved_Checks := Saved_Checks_Stack (Saved_Checks_TOS); | |
3020 | if Debug_Flag_CC then | |
3021 | w ("Conditional_Statements_End: Num_Saved_Checks = ", | |
3022 | Num_Saved_Checks); | |
3023 | end if; | |
3024 | end if; | |
3025 | ||
3026 | Saved_Checks_TOS := Saved_Checks_TOS - 1; | |
3027 | end Conditional_Statements_End; | |
3028 | ||
ee6ba406 | 3029 | --------------------- |
3030 | -- Determine_Range -- | |
3031 | --------------------- | |
3032 | ||
6af1bdbc | 3033 | Cache_Size : constant := 2 ** 10; |
ee6ba406 | 3034 | type Cache_Index is range 0 .. Cache_Size - 1; |
3035 | -- Determine size of below cache (power of 2 is more efficient!) | |
3036 | ||
3037 | Determine_Range_Cache_N : array (Cache_Index) of Node_Id; | |
9c486805 | 3038 | Determine_Range_Cache_V : array (Cache_Index) of Boolean; |
ee6ba406 | 3039 | Determine_Range_Cache_Lo : array (Cache_Index) of Uint; |
3040 | Determine_Range_Cache_Hi : array (Cache_Index) of Uint; | |
feff2f05 | 3041 | -- The above arrays are used to implement a small direct cache for |
3042 | -- Determine_Range calls. Because of the way Determine_Range recursively | |
3043 | -- traces subexpressions, and because overflow checking calls the routine | |
3044 | -- on the way up the tree, a quadratic behavior can otherwise be | |
3045 | -- encountered in large expressions. The cache entry for node N is stored | |
3046 | -- in the (N mod Cache_Size) entry, and can be validated by checking the | |
9c486805 | 3047 | -- actual node value stored there. The Range_Cache_V array records the |
3048 | -- setting of Assume_Valid for the cache entry. | |
ee6ba406 | 3049 | |
3050 | procedure Determine_Range | |
9c486805 | 3051 | (N : Node_Id; |
3052 | OK : out Boolean; | |
3053 | Lo : out Uint; | |
3054 | Hi : out Uint; | |
3055 | Assume_Valid : Boolean := False) | |
ee6ba406 | 3056 | is |
e254d721 | 3057 | Typ : Entity_Id := Etype (N); |
3058 | -- Type to use, may get reset to base type for possibly invalid entity | |
8880be85 | 3059 | |
3060 | Lo_Left : Uint; | |
3061 | Hi_Left : Uint; | |
3062 | -- Lo and Hi bounds of left operand | |
ee6ba406 | 3063 | |
ee6ba406 | 3064 | Lo_Right : Uint; |
ee6ba406 | 3065 | Hi_Right : Uint; |
8880be85 | 3066 | -- Lo and Hi bounds of right (or only) operand |
3067 | ||
3068 | Bound : Node_Id; | |
3069 | -- Temp variable used to hold a bound node | |
3070 | ||
3071 | Hbound : Uint; | |
3072 | -- High bound of base type of expression | |
3073 | ||
3074 | Lor : Uint; | |
3075 | Hir : Uint; | |
3076 | -- Refined values for low and high bounds, after tightening | |
3077 | ||
3078 | OK1 : Boolean; | |
3079 | -- Used in lower level calls to indicate if call succeeded | |
3080 | ||
3081 | Cindex : Cache_Index; | |
3082 | -- Used to search cache | |
ee6ba406 | 3083 | |
3084 | function OK_Operands return Boolean; | |
3085 | -- Used for binary operators. Determines the ranges of the left and | |
3086 | -- right operands, and if they are both OK, returns True, and puts | |
341bd953 | 3087 | -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left. |
ee6ba406 | 3088 | |
3089 | ----------------- | |
3090 | -- OK_Operands -- | |
3091 | ----------------- | |
3092 | ||
3093 | function OK_Operands return Boolean is | |
3094 | begin | |
9c486805 | 3095 | Determine_Range |
3096 | (Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid); | |
ee6ba406 | 3097 | |
3098 | if not OK1 then | |
3099 | return False; | |
3100 | end if; | |
3101 | ||
9c486805 | 3102 | Determine_Range |
3103 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
ee6ba406 | 3104 | return OK1; |
3105 | end OK_Operands; | |
3106 | ||
3107 | -- Start of processing for Determine_Range | |
3108 | ||
3109 | begin | |
87bdc21d | 3110 | -- For temporary constants internally generated to remove side effects |
3111 | -- we must use the corresponding expression to determine the range of | |
3112 | -- the expression. | |
3113 | ||
3114 | if Is_Entity_Name (N) | |
3115 | and then Nkind (Parent (Entity (N))) = N_Object_Declaration | |
3116 | and then Ekind (Entity (N)) = E_Constant | |
3117 | and then Is_Internal_Name (Chars (Entity (N))) | |
3118 | then | |
3119 | Determine_Range | |
3120 | (Expression (Parent (Entity (N))), OK, Lo, Hi, Assume_Valid); | |
3121 | return; | |
3122 | end if; | |
3123 | ||
ee6ba406 | 3124 | -- Prevent junk warnings by initializing range variables |
3125 | ||
3126 | Lo := No_Uint; | |
3127 | Hi := No_Uint; | |
3128 | Lor := No_Uint; | |
3129 | Hir := No_Uint; | |
3130 | ||
a781c0fc | 3131 | -- If type is not defined, we can't determine its range |
ee6ba406 | 3132 | |
a781c0fc | 3133 | if No (Typ) |
3134 | ||
3135 | -- We don't deal with anything except discrete types | |
3136 | ||
3137 | or else not Is_Discrete_Type (Typ) | |
3138 | ||
3139 | -- Ignore type for which an error has been posted, since range in | |
3140 | -- this case may well be a bogosity deriving from the error. Also | |
3141 | -- ignore if error posted on the reference node. | |
3142 | ||
3143 | or else Error_Posted (N) or else Error_Posted (Typ) | |
ee6ba406 | 3144 | then |
3145 | OK := False; | |
3146 | return; | |
3147 | end if; | |
3148 | ||
3149 | -- For all other cases, we can determine the range | |
3150 | ||
3151 | OK := True; | |
3152 | ||
feff2f05 | 3153 | -- If value is compile time known, then the possible range is the one |
3154 | -- value that we know this expression definitely has! | |
ee6ba406 | 3155 | |
3156 | if Compile_Time_Known_Value (N) then | |
3157 | Lo := Expr_Value (N); | |
3158 | Hi := Lo; | |
3159 | return; | |
3160 | end if; | |
3161 | ||
3162 | -- Return if already in the cache | |
3163 | ||
3164 | Cindex := Cache_Index (N mod Cache_Size); | |
3165 | ||
9c486805 | 3166 | if Determine_Range_Cache_N (Cindex) = N |
3167 | and then | |
3168 | Determine_Range_Cache_V (Cindex) = Assume_Valid | |
3169 | then | |
ee6ba406 | 3170 | Lo := Determine_Range_Cache_Lo (Cindex); |
3171 | Hi := Determine_Range_Cache_Hi (Cindex); | |
3172 | return; | |
3173 | end if; | |
3174 | ||
feff2f05 | 3175 | -- Otherwise, start by finding the bounds of the type of the expression, |
3176 | -- the value cannot be outside this range (if it is, then we have an | |
3177 | -- overflow situation, which is a separate check, we are talking here | |
3178 | -- only about the expression value). | |
ee6ba406 | 3179 | |
341bd953 | 3180 | -- First a check, never try to find the bounds of a generic type, since |
3181 | -- these bounds are always junk values, and it is only valid to look at | |
3182 | -- the bounds in an instance. | |
3183 | ||
3184 | if Is_Generic_Type (Typ) then | |
3185 | OK := False; | |
3186 | return; | |
3187 | end if; | |
3188 | ||
9c486805 | 3189 | -- First step, change to use base type unless we know the value is valid |
e254d721 | 3190 | |
9c486805 | 3191 | if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N))) |
3192 | or else Assume_No_Invalid_Values | |
3193 | or else Assume_Valid | |
e254d721 | 3194 | then |
9c486805 | 3195 | null; |
3196 | else | |
3197 | Typ := Underlying_Type (Base_Type (Typ)); | |
e254d721 | 3198 | end if; |
3199 | ||
feff2f05 | 3200 | -- We use the actual bound unless it is dynamic, in which case use the |
3201 | -- corresponding base type bound if possible. If we can't get a bound | |
3202 | -- then we figure we can't determine the range (a peculiar case, that | |
3203 | -- perhaps cannot happen, but there is no point in bombing in this | |
3204 | -- optimization circuit. | |
8880be85 | 3205 | |
3206 | -- First the low bound | |
ee6ba406 | 3207 | |
3208 | Bound := Type_Low_Bound (Typ); | |
3209 | ||
3210 | if Compile_Time_Known_Value (Bound) then | |
3211 | Lo := Expr_Value (Bound); | |
3212 | ||
3213 | elsif Compile_Time_Known_Value (Type_Low_Bound (Base_Type (Typ))) then | |
3214 | Lo := Expr_Value (Type_Low_Bound (Base_Type (Typ))); | |
3215 | ||
3216 | else | |
3217 | OK := False; | |
3218 | return; | |
3219 | end if; | |
3220 | ||
8880be85 | 3221 | -- Now the high bound |
3222 | ||
ee6ba406 | 3223 | Bound := Type_High_Bound (Typ); |
3224 | ||
8880be85 | 3225 | -- We need the high bound of the base type later on, and this should |
3226 | -- always be compile time known. Again, it is not clear that this | |
3227 | -- can ever be false, but no point in bombing. | |
ee6ba406 | 3228 | |
8880be85 | 3229 | if Compile_Time_Known_Value (Type_High_Bound (Base_Type (Typ))) then |
ee6ba406 | 3230 | Hbound := Expr_Value (Type_High_Bound (Base_Type (Typ))); |
3231 | Hi := Hbound; | |
3232 | ||
3233 | else | |
3234 | OK := False; | |
3235 | return; | |
3236 | end if; | |
3237 | ||
feff2f05 | 3238 | -- If we have a static subtype, then that may have a tighter bound so |
3239 | -- use the upper bound of the subtype instead in this case. | |
8880be85 | 3240 | |
3241 | if Compile_Time_Known_Value (Bound) then | |
3242 | Hi := Expr_Value (Bound); | |
3243 | end if; | |
3244 | ||
feff2f05 | 3245 | -- We may be able to refine this value in certain situations. If any |
3246 | -- refinement is possible, then Lor and Hir are set to possibly tighter | |
3247 | -- bounds, and OK1 is set to True. | |
ee6ba406 | 3248 | |
3249 | case Nkind (N) is | |
3250 | ||
3251 | -- For unary plus, result is limited by range of operand | |
3252 | ||
3253 | when N_Op_Plus => | |
9c486805 | 3254 | Determine_Range |
3255 | (Right_Opnd (N), OK1, Lor, Hir, Assume_Valid); | |
ee6ba406 | 3256 | |
3257 | -- For unary minus, determine range of operand, and negate it | |
3258 | ||
3259 | when N_Op_Minus => | |
9c486805 | 3260 | Determine_Range |
3261 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
ee6ba406 | 3262 | |
3263 | if OK1 then | |
3264 | Lor := -Hi_Right; | |
3265 | Hir := -Lo_Right; | |
3266 | end if; | |
3267 | ||
3268 | -- For binary addition, get range of each operand and do the | |
3269 | -- addition to get the result range. | |
3270 | ||
3271 | when N_Op_Add => | |
3272 | if OK_Operands then | |
3273 | Lor := Lo_Left + Lo_Right; | |
3274 | Hir := Hi_Left + Hi_Right; | |
3275 | end if; | |
3276 | ||
feff2f05 | 3277 | -- Division is tricky. The only case we consider is where the right |
3278 | -- operand is a positive constant, and in this case we simply divide | |
3279 | -- the bounds of the left operand | |
ee6ba406 | 3280 | |
3281 | when N_Op_Divide => | |
3282 | if OK_Operands then | |
3283 | if Lo_Right = Hi_Right | |
3284 | and then Lo_Right > 0 | |
3285 | then | |
3286 | Lor := Lo_Left / Lo_Right; | |
3287 | Hir := Hi_Left / Lo_Right; | |
3288 | ||
3289 | else | |
3290 | OK1 := False; | |
3291 | end if; | |
3292 | end if; | |
3293 | ||
feff2f05 | 3294 | -- For binary subtraction, get range of each operand and do the worst |
3295 | -- case subtraction to get the result range. | |
ee6ba406 | 3296 | |
3297 | when N_Op_Subtract => | |
3298 | if OK_Operands then | |
3299 | Lor := Lo_Left - Hi_Right; | |
3300 | Hir := Hi_Left - Lo_Right; | |
3301 | end if; | |
3302 | ||
feff2f05 | 3303 | -- For MOD, if right operand is a positive constant, then result must |
3304 | -- be in the allowable range of mod results. | |
ee6ba406 | 3305 | |
3306 | when N_Op_Mod => | |
3307 | if OK_Operands then | |
9dfe12ae | 3308 | if Lo_Right = Hi_Right |
3309 | and then Lo_Right /= 0 | |
3310 | then | |
ee6ba406 | 3311 | if Lo_Right > 0 then |
3312 | Lor := Uint_0; | |
3313 | Hir := Lo_Right - 1; | |
3314 | ||
9dfe12ae | 3315 | else -- Lo_Right < 0 |
ee6ba406 | 3316 | Lor := Lo_Right + 1; |
3317 | Hir := Uint_0; | |
3318 | end if; | |
3319 | ||
3320 | else | |
3321 | OK1 := False; | |
3322 | end if; | |
3323 | end if; | |
3324 | ||
feff2f05 | 3325 | -- For REM, if right operand is a positive constant, then result must |
3326 | -- be in the allowable range of mod results. | |
ee6ba406 | 3327 | |
3328 | when N_Op_Rem => | |
3329 | if OK_Operands then | |
9dfe12ae | 3330 | if Lo_Right = Hi_Right |
3331 | and then Lo_Right /= 0 | |
3332 | then | |
ee6ba406 | 3333 | declare |
3334 | Dval : constant Uint := (abs Lo_Right) - 1; | |
3335 | ||
3336 | begin | |
3337 | -- The sign of the result depends on the sign of the | |
3338 | -- dividend (but not on the sign of the divisor, hence | |
3339 | -- the abs operation above). | |
3340 | ||
3341 | if Lo_Left < 0 then | |
3342 | Lor := -Dval; | |
3343 | else | |
3344 | Lor := Uint_0; | |
3345 | end if; | |
3346 | ||
3347 | if Hi_Left < 0 then | |
3348 | Hir := Uint_0; | |
3349 | else | |
3350 | Hir := Dval; | |
3351 | end if; | |
3352 | end; | |
3353 | ||
3354 | else | |
3355 | OK1 := False; | |
3356 | end if; | |
3357 | end if; | |
3358 | ||
3359 | -- Attribute reference cases | |
3360 | ||
3361 | when N_Attribute_Reference => | |
3362 | case Attribute_Name (N) is | |
3363 | ||
3364 | -- For Pos/Val attributes, we can refine the range using the | |
ddbf7f2e | 3365 | -- possible range of values of the attribute expression. |
ee6ba406 | 3366 | |
3367 | when Name_Pos | Name_Val => | |
9c486805 | 3368 | Determine_Range |
3369 | (First (Expressions (N)), OK1, Lor, Hir, Assume_Valid); | |
ee6ba406 | 3370 | |
3371 | -- For Length attribute, use the bounds of the corresponding | |
3372 | -- index type to refine the range. | |
3373 | ||
3374 | when Name_Length => | |
3375 | declare | |
3376 | Atyp : Entity_Id := Etype (Prefix (N)); | |
3377 | Inum : Nat; | |
3378 | Indx : Node_Id; | |
3379 | ||
3380 | LL, LU : Uint; | |
3381 | UL, UU : Uint; | |
3382 | ||
3383 | begin | |
3384 | if Is_Access_Type (Atyp) then | |
3385 | Atyp := Designated_Type (Atyp); | |
3386 | end if; | |
3387 | ||
3388 | -- For string literal, we know exact value | |
3389 | ||
3390 | if Ekind (Atyp) = E_String_Literal_Subtype then | |
3391 | OK := True; | |
3392 | Lo := String_Literal_Length (Atyp); | |
3393 | Hi := String_Literal_Length (Atyp); | |
3394 | return; | |
3395 | end if; | |
3396 | ||
3397 | -- Otherwise check for expression given | |
3398 | ||
3399 | if No (Expressions (N)) then | |
3400 | Inum := 1; | |
3401 | else | |
3402 | Inum := | |
3403 | UI_To_Int (Expr_Value (First (Expressions (N)))); | |
3404 | end if; | |
3405 | ||
3406 | Indx := First_Index (Atyp); | |
3407 | for J in 2 .. Inum loop | |
3408 | Indx := Next_Index (Indx); | |
3409 | end loop; | |
3410 | ||
9116df93 | 3411 | -- If the index type is a formal type or derived from |
c8da6114 | 3412 | -- one, the bounds are not static. |
3413 | ||
3414 | if Is_Generic_Type (Root_Type (Etype (Indx))) then | |
3415 | OK := False; | |
3416 | return; | |
3417 | end if; | |
3418 | ||
ee6ba406 | 3419 | Determine_Range |
9c486805 | 3420 | (Type_Low_Bound (Etype (Indx)), OK1, LL, LU, |
3421 | Assume_Valid); | |
ee6ba406 | 3422 | |
3423 | if OK1 then | |
3424 | Determine_Range | |
9c486805 | 3425 | (Type_High_Bound (Etype (Indx)), OK1, UL, UU, |
3426 | Assume_Valid); | |
ee6ba406 | 3427 | |
3428 | if OK1 then | |
3429 | ||
3430 | -- The maximum value for Length is the biggest | |
3431 | -- possible gap between the values of the bounds. | |
3432 | -- But of course, this value cannot be negative. | |
3433 | ||
9c486805 | 3434 | Hir := UI_Max (Uint_0, UU - LL + 1); |
ee6ba406 | 3435 | |
3436 | -- For constrained arrays, the minimum value for | |
3437 | -- Length is taken from the actual value of the | |
9116df93 | 3438 | -- bounds, since the index will be exactly of this |
3439 | -- subtype. | |
ee6ba406 | 3440 | |
3441 | if Is_Constrained (Atyp) then | |
9c486805 | 3442 | Lor := UI_Max (Uint_0, UL - LU + 1); |
ee6ba406 | 3443 | |
3444 | -- For an unconstrained array, the minimum value | |
3445 | -- for length is always zero. | |
3446 | ||
3447 | else | |
3448 | Lor := Uint_0; | |
3449 | end if; | |
3450 | end if; | |
3451 | end if; | |
3452 | end; | |
3453 | ||
3454 | -- No special handling for other attributes | |
9116df93 | 3455 | -- Probably more opportunities exist here??? |
ee6ba406 | 3456 | |
3457 | when others => | |
3458 | OK1 := False; | |
3459 | ||
3460 | end case; | |
3461 | ||
feff2f05 | 3462 | -- For type conversion from one discrete type to another, we can |
3463 | -- refine the range using the converted value. | |
ee6ba406 | 3464 | |
3465 | when N_Type_Conversion => | |
9c486805 | 3466 | Determine_Range (Expression (N), OK1, Lor, Hir, Assume_Valid); |
ee6ba406 | 3467 | |
3468 | -- Nothing special to do for all other expression kinds | |
3469 | ||
3470 | when others => | |
3471 | OK1 := False; | |
3472 | Lor := No_Uint; | |
3473 | Hir := No_Uint; | |
3474 | end case; | |
3475 | ||
9116df93 | 3476 | -- At this stage, if OK1 is true, then we know that the actual result of |
3477 | -- the computed expression is in the range Lor .. Hir. We can use this | |
3478 | -- to restrict the possible range of results. | |
ee6ba406 | 3479 | |
dd688950 | 3480 | -- If one of the computed bounds is outside the range of the base type, |
3481 | -- the expression may raise an exception and we better indicate that | |
3482 | -- the evaluation has failed, at least if checks are enabled. | |
3483 | ||
3484 | if Enable_Overflow_Checks | |
3485 | and then not Is_Entity_Name (N) | |
c04fff3e | 3486 | and then (Lor < Lo or else Hir > Hi) |
dd688950 | 3487 | then |
3488 | OK := False; | |
3489 | return; | |
3490 | end if; | |
3491 | ||
ee6ba406 | 3492 | if OK1 then |
3493 | ||
9116df93 | 3494 | -- If the refined value of the low bound is greater than the type |
3495 | -- high bound, then reset it to the more restrictive value. However, | |
3496 | -- we do NOT do this for the case of a modular type where the | |
3497 | -- possible upper bound on the value is above the base type high | |
3498 | -- bound, because that means the result could wrap. | |
ee6ba406 | 3499 | |
3500 | if Lor > Lo | |
9116df93 | 3501 | and then not (Is_Modular_Integer_Type (Typ) and then Hir > Hbound) |
ee6ba406 | 3502 | then |
3503 | Lo := Lor; | |
3504 | end if; | |
3505 | ||
9116df93 | 3506 | -- Similarly, if the refined value of the high bound is less than the |
3507 | -- value so far, then reset it to the more restrictive value. Again, | |
3508 | -- we do not do this if the refined low bound is negative for a | |
3509 | -- modular type, since this would wrap. | |
ee6ba406 | 3510 | |
3511 | if Hir < Hi | |
9116df93 | 3512 | and then not (Is_Modular_Integer_Type (Typ) and then Lor < Uint_0) |
ee6ba406 | 3513 | then |
3514 | Hi := Hir; | |
3515 | end if; | |
3516 | end if; | |
3517 | ||
3518 | -- Set cache entry for future call and we are all done | |
3519 | ||
3520 | Determine_Range_Cache_N (Cindex) := N; | |
9c486805 | 3521 | Determine_Range_Cache_V (Cindex) := Assume_Valid; |
ee6ba406 | 3522 | Determine_Range_Cache_Lo (Cindex) := Lo; |
3523 | Determine_Range_Cache_Hi (Cindex) := Hi; | |
3524 | return; | |
3525 | ||
9116df93 | 3526 | -- If any exception occurs, it means that we have some bug in the compiler, |
3527 | -- possibly triggered by a previous error, or by some unforeseen peculiar | |
ee6ba406 | 3528 | -- occurrence. However, this is only an optimization attempt, so there is |
3529 | -- really no point in crashing the compiler. Instead we just decide, too | |
3530 | -- bad, we can't figure out a range in this case after all. | |
3531 | ||
3532 | exception | |
3533 | when others => | |
3534 | ||
3535 | -- Debug flag K disables this behavior (useful for debugging) | |
3536 | ||
3537 | if Debug_Flag_K then | |
3538 | raise; | |
3539 | else | |
3540 | OK := False; | |
3541 | Lo := No_Uint; | |
3542 | Hi := No_Uint; | |
3543 | return; | |
3544 | end if; | |
ee6ba406 | 3545 | end Determine_Range; |
3546 | ||
3547 | ------------------------------------ | |
3548 | -- Discriminant_Checks_Suppressed -- | |
3549 | ------------------------------------ | |
3550 | ||
3551 | function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is | |
3552 | begin | |
9dfe12ae | 3553 | if Present (E) then |
3554 | if Is_Unchecked_Union (E) then | |
3555 | return True; | |
3556 | elsif Checks_May_Be_Suppressed (E) then | |
3557 | return Is_Check_Suppressed (E, Discriminant_Check); | |
3558 | end if; | |
3559 | end if; | |
3560 | ||
3561 | return Scope_Suppress (Discriminant_Check); | |
ee6ba406 | 3562 | end Discriminant_Checks_Suppressed; |
3563 | ||
3564 | -------------------------------- | |
3565 | -- Division_Checks_Suppressed -- | |
3566 | -------------------------------- | |
3567 | ||
3568 | function Division_Checks_Suppressed (E : Entity_Id) return Boolean is | |
3569 | begin | |
9dfe12ae | 3570 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
3571 | return Is_Check_Suppressed (E, Division_Check); | |
3572 | else | |
3573 | return Scope_Suppress (Division_Check); | |
3574 | end if; | |
ee6ba406 | 3575 | end Division_Checks_Suppressed; |
3576 | ||
3577 | ----------------------------------- | |
3578 | -- Elaboration_Checks_Suppressed -- | |
3579 | ----------------------------------- | |
3580 | ||
3581 | function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is | |
3582 | begin | |
38f5559f | 3583 | -- The complication in this routine is that if we are in the dynamic |
3584 | -- model of elaboration, we also check All_Checks, since All_Checks | |
3585 | -- does not set Elaboration_Check explicitly. | |
3586 | ||
9dfe12ae | 3587 | if Present (E) then |
3588 | if Kill_Elaboration_Checks (E) then | |
3589 | return True; | |
38f5559f | 3590 | |
9dfe12ae | 3591 | elsif Checks_May_Be_Suppressed (E) then |
38f5559f | 3592 | if Is_Check_Suppressed (E, Elaboration_Check) then |
3593 | return True; | |
3594 | elsif Dynamic_Elaboration_Checks then | |
3595 | return Is_Check_Suppressed (E, All_Checks); | |
3596 | else | |
3597 | return False; | |
3598 | end if; | |
9dfe12ae | 3599 | end if; |
3600 | end if; | |
3601 | ||
38f5559f | 3602 | if Scope_Suppress (Elaboration_Check) then |
3603 | return True; | |
3604 | elsif Dynamic_Elaboration_Checks then | |
3605 | return Scope_Suppress (All_Checks); | |
3606 | else | |
3607 | return False; | |
3608 | end if; | |
ee6ba406 | 3609 | end Elaboration_Checks_Suppressed; |
3610 | ||
9dfe12ae | 3611 | --------------------------- |
3612 | -- Enable_Overflow_Check -- | |
3613 | --------------------------- | |
3614 | ||
3615 | procedure Enable_Overflow_Check (N : Node_Id) is | |
3616 | Typ : constant Entity_Id := Base_Type (Etype (N)); | |
3617 | Chk : Nat; | |
3618 | OK : Boolean; | |
3619 | Ent : Entity_Id; | |
3620 | Ofs : Uint; | |
3621 | Lo : Uint; | |
3622 | Hi : Uint; | |
ee6ba406 | 3623 | |
ee6ba406 | 3624 | begin |
9dfe12ae | 3625 | if Debug_Flag_CC then |
3626 | w ("Enable_Overflow_Check for node ", Int (N)); | |
3627 | Write_Str (" Source location = "); | |
3628 | wl (Sloc (N)); | |
00c403ee | 3629 | pg (Union_Id (N)); |
ee6ba406 | 3630 | end if; |
ee6ba406 | 3631 | |
75209ec5 | 3632 | -- No check if overflow checks suppressed for type of node |
3633 | ||
3634 | if Present (Etype (N)) | |
3635 | and then Overflow_Checks_Suppressed (Etype (N)) | |
3636 | then | |
3637 | return; | |
3638 | ||
49260fa5 | 3639 | -- Nothing to do for unsigned integer types, which do not overflow |
3640 | ||
3641 | elsif Is_Modular_Integer_Type (Typ) then | |
3642 | return; | |
3643 | ||
feff2f05 | 3644 | -- Nothing to do if the range of the result is known OK. We skip this |
3645 | -- for conversions, since the caller already did the check, and in any | |
3646 | -- case the condition for deleting the check for a type conversion is | |
cc60bd16 | 3647 | -- different. |
ee6ba406 | 3648 | |
75209ec5 | 3649 | elsif Nkind (N) /= N_Type_Conversion then |
9c486805 | 3650 | Determine_Range (N, OK, Lo, Hi, Assume_Valid => True); |
ee6ba406 | 3651 | |
cc60bd16 | 3652 | -- Note in the test below that we assume that the range is not OK |
3653 | -- if a bound of the range is equal to that of the type. That's not | |
3654 | -- quite accurate but we do this for the following reasons: | |
ee6ba406 | 3655 | |
9dfe12ae | 3656 | -- a) The way that Determine_Range works, it will typically report |
3657 | -- the bounds of the value as being equal to the bounds of the | |
3658 | -- type, because it either can't tell anything more precise, or | |
3659 | -- does not think it is worth the effort to be more precise. | |
ee6ba406 | 3660 | |
9dfe12ae | 3661 | -- b) It is very unusual to have a situation in which this would |
3662 | -- generate an unnecessary overflow check (an example would be | |
3663 | -- a subtype with a range 0 .. Integer'Last - 1 to which the | |
cc60bd16 | 3664 | -- literal value one is added). |
ee6ba406 | 3665 | |
9dfe12ae | 3666 | -- c) The alternative is a lot of special casing in this routine |
3667 | -- which would partially duplicate Determine_Range processing. | |
ee6ba406 | 3668 | |
9dfe12ae | 3669 | if OK |
3670 | and then Lo > Expr_Value (Type_Low_Bound (Typ)) | |
3671 | and then Hi < Expr_Value (Type_High_Bound (Typ)) | |
3672 | then | |
3673 | if Debug_Flag_CC then | |
3674 | w ("No overflow check required"); | |
3675 | end if; | |
3676 | ||
3677 | return; | |
3678 | end if; | |
3679 | end if; | |
3680 | ||
feff2f05 | 3681 | -- If not in optimizing mode, set flag and we are done. We are also done |
3682 | -- (and just set the flag) if the type is not a discrete type, since it | |
3683 | -- is not worth the effort to eliminate checks for other than discrete | |
3684 | -- types. In addition, we take this same path if we have stored the | |
3685 | -- maximum number of checks possible already (a very unlikely situation, | |
3686 | -- but we do not want to blow up!) | |
9dfe12ae | 3687 | |
3688 | if Optimization_Level = 0 | |
3689 | or else not Is_Discrete_Type (Etype (N)) | |
3690 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 3691 | then |
00c403ee | 3692 | Activate_Overflow_Check (N); |
9dfe12ae | 3693 | |
3694 | if Debug_Flag_CC then | |
3695 | w ("Optimization off"); | |
3696 | end if; | |
3697 | ||
ee6ba406 | 3698 | return; |
9dfe12ae | 3699 | end if; |
ee6ba406 | 3700 | |
9dfe12ae | 3701 | -- Otherwise evaluate and check the expression |
3702 | ||
3703 | Find_Check | |
3704 | (Expr => N, | |
3705 | Check_Type => 'O', | |
3706 | Target_Type => Empty, | |
3707 | Entry_OK => OK, | |
3708 | Check_Num => Chk, | |
3709 | Ent => Ent, | |
3710 | Ofs => Ofs); | |
3711 | ||
3712 | if Debug_Flag_CC then | |
3713 | w ("Called Find_Check"); | |
3714 | w (" OK = ", OK); | |
3715 | ||
3716 | if OK then | |
3717 | w (" Check_Num = ", Chk); | |
3718 | w (" Ent = ", Int (Ent)); | |
3719 | Write_Str (" Ofs = "); | |
3720 | pid (Ofs); | |
3721 | end if; | |
3722 | end if; | |
ee6ba406 | 3723 | |
9dfe12ae | 3724 | -- If check is not of form to optimize, then set flag and we are done |
3725 | ||
3726 | if not OK then | |
00c403ee | 3727 | Activate_Overflow_Check (N); |
ee6ba406 | 3728 | return; |
9dfe12ae | 3729 | end if; |
ee6ba406 | 3730 | |
9dfe12ae | 3731 | -- If check is already performed, then return without setting flag |
3732 | ||
3733 | if Chk /= 0 then | |
3734 | if Debug_Flag_CC then | |
3735 | w ("Check suppressed!"); | |
3736 | end if; | |
ee6ba406 | 3737 | |
ee6ba406 | 3738 | return; |
9dfe12ae | 3739 | end if; |
ee6ba406 | 3740 | |
9dfe12ae | 3741 | -- Here we will make a new entry for the new check |
3742 | ||
00c403ee | 3743 | Activate_Overflow_Check (N); |
9dfe12ae | 3744 | Num_Saved_Checks := Num_Saved_Checks + 1; |
3745 | Saved_Checks (Num_Saved_Checks) := | |
3746 | (Killed => False, | |
3747 | Entity => Ent, | |
3748 | Offset => Ofs, | |
3749 | Check_Type => 'O', | |
3750 | Target_Type => Empty); | |
3751 | ||
3752 | if Debug_Flag_CC then | |
3753 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
3754 | w (" Entity = ", Int (Ent)); | |
3755 | Write_Str (" Offset = "); | |
3756 | pid (Ofs); | |
3757 | w (" Check_Type = O"); | |
3758 | w (" Target_Type = Empty"); | |
3759 | end if; | |
ee6ba406 | 3760 | |
feff2f05 | 3761 | -- If we get an exception, then something went wrong, probably because of |
3762 | -- an error in the structure of the tree due to an incorrect program. Or it | |
3763 | -- may be a bug in the optimization circuit. In either case the safest | |
3764 | -- thing is simply to set the check flag unconditionally. | |
9dfe12ae | 3765 | |
3766 | exception | |
3767 | when others => | |
00c403ee | 3768 | Activate_Overflow_Check (N); |
9dfe12ae | 3769 | |
3770 | if Debug_Flag_CC then | |
3771 | w (" exception occurred, overflow flag set"); | |
3772 | end if; | |
3773 | ||
3774 | return; | |
3775 | end Enable_Overflow_Check; | |
3776 | ||
3777 | ------------------------ | |
3778 | -- Enable_Range_Check -- | |
3779 | ------------------------ | |
3780 | ||
3781 | procedure Enable_Range_Check (N : Node_Id) is | |
3782 | Chk : Nat; | |
3783 | OK : Boolean; | |
3784 | Ent : Entity_Id; | |
3785 | Ofs : Uint; | |
3786 | Ttyp : Entity_Id; | |
3787 | P : Node_Id; | |
3788 | ||
3789 | begin | |
feff2f05 | 3790 | -- Return if unchecked type conversion with range check killed. In this |
3791 | -- case we never set the flag (that's what Kill_Range_Check is about!) | |
9dfe12ae | 3792 | |
3793 | if Nkind (N) = N_Unchecked_Type_Conversion | |
3794 | and then Kill_Range_Check (N) | |
ee6ba406 | 3795 | then |
3796 | return; | |
9dfe12ae | 3797 | end if; |
ee6ba406 | 3798 | |
55e8372b | 3799 | -- Do not set range check flag if parent is assignment statement or |
3800 | -- object declaration with Suppress_Assignment_Checks flag set | |
3801 | ||
3802 | if Nkind_In (Parent (N), N_Assignment_Statement, N_Object_Declaration) | |
3803 | and then Suppress_Assignment_Checks (Parent (N)) | |
3804 | then | |
3805 | return; | |
3806 | end if; | |
3807 | ||
0577b0b1 | 3808 | -- Check for various cases where we should suppress the range check |
3809 | ||
3810 | -- No check if range checks suppressed for type of node | |
3811 | ||
3812 | if Present (Etype (N)) | |
3813 | and then Range_Checks_Suppressed (Etype (N)) | |
3814 | then | |
3815 | return; | |
3816 | ||
3817 | -- No check if node is an entity name, and range checks are suppressed | |
3818 | -- for this entity, or for the type of this entity. | |
3819 | ||
3820 | elsif Is_Entity_Name (N) | |
3821 | and then (Range_Checks_Suppressed (Entity (N)) | |
3822 | or else Range_Checks_Suppressed (Etype (Entity (N)))) | |
3823 | then | |
3824 | return; | |
3825 | ||
3826 | -- No checks if index of array, and index checks are suppressed for | |
3827 | -- the array object or the type of the array. | |
3828 | ||
3829 | elsif Nkind (Parent (N)) = N_Indexed_Component then | |
3830 | declare | |
3831 | Pref : constant Node_Id := Prefix (Parent (N)); | |
3832 | begin | |
3833 | if Is_Entity_Name (Pref) | |
3834 | and then Index_Checks_Suppressed (Entity (Pref)) | |
3835 | then | |
3836 | return; | |
3837 | elsif Index_Checks_Suppressed (Etype (Pref)) then | |
3838 | return; | |
3839 | end if; | |
3840 | end; | |
3841 | end if; | |
3842 | ||
9dfe12ae | 3843 | -- Debug trace output |
ee6ba406 | 3844 | |
9dfe12ae | 3845 | if Debug_Flag_CC then |
3846 | w ("Enable_Range_Check for node ", Int (N)); | |
3847 | Write_Str (" Source location = "); | |
3848 | wl (Sloc (N)); | |
00c403ee | 3849 | pg (Union_Id (N)); |
9dfe12ae | 3850 | end if; |
3851 | ||
feff2f05 | 3852 | -- If not in optimizing mode, set flag and we are done. We are also done |
3853 | -- (and just set the flag) if the type is not a discrete type, since it | |
3854 | -- is not worth the effort to eliminate checks for other than discrete | |
3855 | -- types. In addition, we take this same path if we have stored the | |
3856 | -- maximum number of checks possible already (a very unlikely situation, | |
3857 | -- but we do not want to blow up!) | |
9dfe12ae | 3858 | |
3859 | if Optimization_Level = 0 | |
3860 | or else No (Etype (N)) | |
3861 | or else not Is_Discrete_Type (Etype (N)) | |
3862 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 3863 | then |
00c403ee | 3864 | Activate_Range_Check (N); |
9dfe12ae | 3865 | |
3866 | if Debug_Flag_CC then | |
3867 | w ("Optimization off"); | |
3868 | end if; | |
3869 | ||
ee6ba406 | 3870 | return; |
9dfe12ae | 3871 | end if; |
ee6ba406 | 3872 | |
9dfe12ae | 3873 | -- Otherwise find out the target type |
ee6ba406 | 3874 | |
9dfe12ae | 3875 | P := Parent (N); |
ee6ba406 | 3876 | |
9dfe12ae | 3877 | -- For assignment, use left side subtype |
3878 | ||
3879 | if Nkind (P) = N_Assignment_Statement | |
3880 | and then Expression (P) = N | |
3881 | then | |
3882 | Ttyp := Etype (Name (P)); | |
3883 | ||
3884 | -- For indexed component, use subscript subtype | |
3885 | ||
3886 | elsif Nkind (P) = N_Indexed_Component then | |
3887 | declare | |
3888 | Atyp : Entity_Id; | |
3889 | Indx : Node_Id; | |
3890 | Subs : Node_Id; | |
3891 | ||
3892 | begin | |
3893 | Atyp := Etype (Prefix (P)); | |
3894 | ||
3895 | if Is_Access_Type (Atyp) then | |
3896 | Atyp := Designated_Type (Atyp); | |
f07ea091 | 3897 | |
3898 | -- If the prefix is an access to an unconstrained array, | |
feff2f05 | 3899 | -- perform check unconditionally: it depends on the bounds of |
3900 | -- an object and we cannot currently recognize whether the test | |
3901 | -- may be redundant. | |
f07ea091 | 3902 | |
3903 | if not Is_Constrained (Atyp) then | |
00c403ee | 3904 | Activate_Range_Check (N); |
f07ea091 | 3905 | return; |
3906 | end if; | |
7189d17f | 3907 | |
feff2f05 | 3908 | -- Ditto if the prefix is an explicit dereference whose designated |
3909 | -- type is unconstrained. | |
7189d17f | 3910 | |
3911 | elsif Nkind (Prefix (P)) = N_Explicit_Dereference | |
3912 | and then not Is_Constrained (Atyp) | |
3913 | then | |
00c403ee | 3914 | Activate_Range_Check (N); |
7189d17f | 3915 | return; |
9dfe12ae | 3916 | end if; |
3917 | ||
3918 | Indx := First_Index (Atyp); | |
3919 | Subs := First (Expressions (P)); | |
3920 | loop | |
3921 | if Subs = N then | |
3922 | Ttyp := Etype (Indx); | |
3923 | exit; | |
3924 | end if; | |
3925 | ||
3926 | Next_Index (Indx); | |
3927 | Next (Subs); | |
3928 | end loop; | |
3929 | end; | |
3930 | ||
3931 | -- For now, ignore all other cases, they are not so interesting | |
3932 | ||
3933 | else | |
3934 | if Debug_Flag_CC then | |
3935 | w (" target type not found, flag set"); | |
3936 | end if; | |
3937 | ||
00c403ee | 3938 | Activate_Range_Check (N); |
9dfe12ae | 3939 | return; |
3940 | end if; | |
3941 | ||
3942 | -- Evaluate and check the expression | |
3943 | ||
3944 | Find_Check | |
3945 | (Expr => N, | |
3946 | Check_Type => 'R', | |
3947 | Target_Type => Ttyp, | |
3948 | Entry_OK => OK, | |
3949 | Check_Num => Chk, | |
3950 | Ent => Ent, | |
3951 | Ofs => Ofs); | |
3952 | ||
3953 | if Debug_Flag_CC then | |
3954 | w ("Called Find_Check"); | |
3955 | w ("Target_Typ = ", Int (Ttyp)); | |
3956 | w (" OK = ", OK); | |
3957 | ||
3958 | if OK then | |
3959 | w (" Check_Num = ", Chk); | |
3960 | w (" Ent = ", Int (Ent)); | |
3961 | Write_Str (" Ofs = "); | |
3962 | pid (Ofs); | |
3963 | end if; | |
3964 | end if; | |
3965 | ||
3966 | -- If check is not of form to optimize, then set flag and we are done | |
3967 | ||
3968 | if not OK then | |
3969 | if Debug_Flag_CC then | |
3970 | w (" expression not of optimizable type, flag set"); | |
3971 | end if; | |
3972 | ||
00c403ee | 3973 | Activate_Range_Check (N); |
9dfe12ae | 3974 | return; |
3975 | end if; | |
3976 | ||
3977 | -- If check is already performed, then return without setting flag | |
3978 | ||
3979 | if Chk /= 0 then | |
3980 | if Debug_Flag_CC then | |
3981 | w ("Check suppressed!"); | |
3982 | end if; | |
3983 | ||
3984 | return; | |
3985 | end if; | |
3986 | ||
3987 | -- Here we will make a new entry for the new check | |
3988 | ||
00c403ee | 3989 | Activate_Range_Check (N); |
9dfe12ae | 3990 | Num_Saved_Checks := Num_Saved_Checks + 1; |
3991 | Saved_Checks (Num_Saved_Checks) := | |
3992 | (Killed => False, | |
3993 | Entity => Ent, | |
3994 | Offset => Ofs, | |
3995 | Check_Type => 'R', | |
3996 | Target_Type => Ttyp); | |
3997 | ||
3998 | if Debug_Flag_CC then | |
3999 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
4000 | w (" Entity = ", Int (Ent)); | |
4001 | Write_Str (" Offset = "); | |
4002 | pid (Ofs); | |
4003 | w (" Check_Type = R"); | |
4004 | w (" Target_Type = ", Int (Ttyp)); | |
00c403ee | 4005 | pg (Union_Id (Ttyp)); |
9dfe12ae | 4006 | end if; |
4007 | ||
feff2f05 | 4008 | -- If we get an exception, then something went wrong, probably because of |
4009 | -- an error in the structure of the tree due to an incorrect program. Or | |
4010 | -- it may be a bug in the optimization circuit. In either case the safest | |
4011 | -- thing is simply to set the check flag unconditionally. | |
9dfe12ae | 4012 | |
4013 | exception | |
4014 | when others => | |
00c403ee | 4015 | Activate_Range_Check (N); |
9dfe12ae | 4016 | |
4017 | if Debug_Flag_CC then | |
4018 | w (" exception occurred, range flag set"); | |
4019 | end if; | |
4020 | ||
4021 | return; | |
4022 | end Enable_Range_Check; | |
4023 | ||
4024 | ------------------ | |
4025 | -- Ensure_Valid -- | |
4026 | ------------------ | |
4027 | ||
4028 | procedure Ensure_Valid (Expr : Node_Id; Holes_OK : Boolean := False) is | |
4029 | Typ : constant Entity_Id := Etype (Expr); | |
4030 | ||
4031 | begin | |
4032 | -- Ignore call if we are not doing any validity checking | |
4033 | ||
4034 | if not Validity_Checks_On then | |
4035 | return; | |
4036 | ||
0577b0b1 | 4037 | -- Ignore call if range or validity checks suppressed on entity or type |
9dfe12ae | 4038 | |
0577b0b1 | 4039 | elsif Range_Or_Validity_Checks_Suppressed (Expr) then |
9dfe12ae | 4040 | return; |
4041 | ||
feff2f05 | 4042 | -- No check required if expression is from the expander, we assume the |
4043 | -- expander will generate whatever checks are needed. Note that this is | |
4044 | -- not just an optimization, it avoids infinite recursions! | |
9dfe12ae | 4045 | |
4046 | -- Unchecked conversions must be checked, unless they are initialized | |
4047 | -- scalar values, as in a component assignment in an init proc. | |
4048 | ||
4049 | -- In addition, we force a check if Force_Validity_Checks is set | |
4050 | ||
4051 | elsif not Comes_From_Source (Expr) | |
4052 | and then not Force_Validity_Checks | |
4053 | and then (Nkind (Expr) /= N_Unchecked_Type_Conversion | |
4054 | or else Kill_Range_Check (Expr)) | |
4055 | then | |
4056 | return; | |
4057 | ||
4058 | -- No check required if expression is known to have valid value | |
4059 | ||
4060 | elsif Expr_Known_Valid (Expr) then | |
4061 | return; | |
4062 | ||
feff2f05 | 4063 | -- Ignore case of enumeration with holes where the flag is set not to |
4064 | -- worry about holes, since no special validity check is needed | |
9dfe12ae | 4065 | |
4066 | elsif Is_Enumeration_Type (Typ) | |
4067 | and then Has_Non_Standard_Rep (Typ) | |
4068 | and then Holes_OK | |
4069 | then | |
4070 | return; | |
4071 | ||
f2a06be9 | 4072 | -- No check required on the left-hand side of an assignment |
9dfe12ae | 4073 | |
4074 | elsif Nkind (Parent (Expr)) = N_Assignment_Statement | |
4075 | and then Expr = Name (Parent (Expr)) | |
4076 | then | |
4077 | return; | |
4078 | ||
6fb3c314 | 4079 | -- No check on a universal real constant. The context will eventually |
38f5559f | 4080 | -- convert it to a machine number for some target type, or report an |
4081 | -- illegality. | |
4082 | ||
4083 | elsif Nkind (Expr) = N_Real_Literal | |
4084 | and then Etype (Expr) = Universal_Real | |
4085 | then | |
4086 | return; | |
4087 | ||
6fb3c314 | 4088 | -- If the expression denotes a component of a packed boolean array, |
0577b0b1 | 4089 | -- no possible check applies. We ignore the old ACATS chestnuts that |
4090 | -- involve Boolean range True..True. | |
4091 | ||
4092 | -- Note: validity checks are generated for expressions that yield a | |
4093 | -- scalar type, when it is possible to create a value that is outside of | |
4094 | -- the type. If this is a one-bit boolean no such value exists. This is | |
4095 | -- an optimization, and it also prevents compiler blowing up during the | |
4096 | -- elaboration of improperly expanded packed array references. | |
4097 | ||
4098 | elsif Nkind (Expr) = N_Indexed_Component | |
4099 | and then Is_Bit_Packed_Array (Etype (Prefix (Expr))) | |
4100 | and then Root_Type (Etype (Expr)) = Standard_Boolean | |
4101 | then | |
4102 | return; | |
4103 | ||
9dfe12ae | 4104 | -- An annoying special case. If this is an out parameter of a scalar |
4105 | -- type, then the value is not going to be accessed, therefore it is | |
4106 | -- inappropriate to do any validity check at the call site. | |
4107 | ||
4108 | else | |
4109 | -- Only need to worry about scalar types | |
4110 | ||
4111 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 4112 | declare |
4113 | P : Node_Id; | |
4114 | N : Node_Id; | |
4115 | E : Entity_Id; | |
4116 | F : Entity_Id; | |
4117 | A : Node_Id; | |
4118 | L : List_Id; | |
4119 | ||
4120 | begin | |
4121 | -- Find actual argument (which may be a parameter association) | |
4122 | -- and the parent of the actual argument (the call statement) | |
4123 | ||
4124 | N := Expr; | |
4125 | P := Parent (Expr); | |
4126 | ||
4127 | if Nkind (P) = N_Parameter_Association then | |
4128 | N := P; | |
4129 | P := Parent (N); | |
4130 | end if; | |
4131 | ||
feff2f05 | 4132 | -- Only need to worry if we are argument of a procedure call |
4133 | -- since functions don't have out parameters. If this is an | |
4134 | -- indirect or dispatching call, get signature from the | |
4135 | -- subprogram type. | |
ee6ba406 | 4136 | |
4137 | if Nkind (P) = N_Procedure_Call_Statement then | |
4138 | L := Parameter_Associations (P); | |
9dfe12ae | 4139 | |
4140 | if Is_Entity_Name (Name (P)) then | |
4141 | E := Entity (Name (P)); | |
4142 | else | |
4143 | pragma Assert (Nkind (Name (P)) = N_Explicit_Dereference); | |
4144 | E := Etype (Name (P)); | |
4145 | end if; | |
ee6ba406 | 4146 | |
feff2f05 | 4147 | -- Only need to worry if there are indeed actuals, and if |
4148 | -- this could be a procedure call, otherwise we cannot get a | |
4149 | -- match (either we are not an argument, or the mode of the | |
4150 | -- formal is not OUT). This test also filters out the | |
4151 | -- generic case. | |
ee6ba406 | 4152 | |
4153 | if Is_Non_Empty_List (L) | |
4154 | and then Is_Subprogram (E) | |
4155 | then | |
feff2f05 | 4156 | -- This is the loop through parameters, looking for an |
4157 | -- OUT parameter for which we are the argument. | |
ee6ba406 | 4158 | |
4159 | F := First_Formal (E); | |
4160 | A := First (L); | |
ee6ba406 | 4161 | while Present (F) loop |
4162 | if Ekind (F) = E_Out_Parameter and then A = N then | |
4163 | return; | |
4164 | end if; | |
4165 | ||
4166 | Next_Formal (F); | |
4167 | Next (A); | |
4168 | end loop; | |
4169 | end if; | |
4170 | end if; | |
4171 | end; | |
4172 | end if; | |
4173 | end if; | |
4174 | ||
fa6a6949 | 4175 | -- If this is a boolean expression, only its elementary operands need |
90a07d4c | 4176 | -- checking: if they are valid, a boolean or short-circuit operation |
4177 | -- with them will be valid as well. | |
784d4230 | 4178 | |
4179 | if Base_Type (Typ) = Standard_Boolean | |
7af38999 | 4180 | and then |
fa6a6949 | 4181 | (Nkind (Expr) in N_Op or else Nkind (Expr) in N_Short_Circuit) |
784d4230 | 4182 | then |
4183 | return; | |
4184 | end if; | |
4185 | ||
0577b0b1 | 4186 | -- If we fall through, a validity check is required |
ee6ba406 | 4187 | |
4188 | Insert_Valid_Check (Expr); | |
ce7498d3 | 4189 | |
4190 | if Is_Entity_Name (Expr) | |
4191 | and then Safe_To_Capture_Value (Expr, Entity (Expr)) | |
4192 | then | |
4193 | Set_Is_Known_Valid (Entity (Expr)); | |
4194 | end if; | |
ee6ba406 | 4195 | end Ensure_Valid; |
4196 | ||
4197 | ---------------------- | |
4198 | -- Expr_Known_Valid -- | |
4199 | ---------------------- | |
4200 | ||
4201 | function Expr_Known_Valid (Expr : Node_Id) return Boolean is | |
4202 | Typ : constant Entity_Id := Etype (Expr); | |
4203 | ||
4204 | begin | |
feff2f05 | 4205 | -- Non-scalar types are always considered valid, since they never give |
4206 | -- rise to the issues of erroneous or bounded error behavior that are | |
4207 | -- the concern. In formal reference manual terms the notion of validity | |
4208 | -- only applies to scalar types. Note that even when packed arrays are | |
4209 | -- represented using modular types, they are still arrays semantically, | |
4210 | -- so they are also always valid (in particular, the unused bits can be | |
4211 | -- random rubbish without affecting the validity of the array value). | |
ee6ba406 | 4212 | |
fa814356 | 4213 | if not Is_Scalar_Type (Typ) or else Is_Packed_Array_Type (Typ) then |
ee6ba406 | 4214 | return True; |
4215 | ||
4216 | -- If no validity checking, then everything is considered valid | |
4217 | ||
4218 | elsif not Validity_Checks_On then | |
4219 | return True; | |
4220 | ||
4221 | -- Floating-point types are considered valid unless floating-point | |
4222 | -- validity checks have been specifically turned on. | |
4223 | ||
4224 | elsif Is_Floating_Point_Type (Typ) | |
4225 | and then not Validity_Check_Floating_Point | |
4226 | then | |
4227 | return True; | |
4228 | ||
feff2f05 | 4229 | -- If the expression is the value of an object that is known to be |
4230 | -- valid, then clearly the expression value itself is valid. | |
ee6ba406 | 4231 | |
4232 | elsif Is_Entity_Name (Expr) | |
4233 | and then Is_Known_Valid (Entity (Expr)) | |
4234 | then | |
4235 | return True; | |
4236 | ||
0577b0b1 | 4237 | -- References to discriminants are always considered valid. The value |
4238 | -- of a discriminant gets checked when the object is built. Within the | |
4239 | -- record, we consider it valid, and it is important to do so, since | |
4240 | -- otherwise we can try to generate bogus validity checks which | |
feff2f05 | 4241 | -- reference discriminants out of scope. Discriminants of concurrent |
4242 | -- types are excluded for the same reason. | |
0577b0b1 | 4243 | |
4244 | elsif Is_Entity_Name (Expr) | |
feff2f05 | 4245 | and then Denotes_Discriminant (Expr, Check_Concurrent => True) |
0577b0b1 | 4246 | then |
4247 | return True; | |
4248 | ||
feff2f05 | 4249 | -- If the type is one for which all values are known valid, then we are |
4250 | -- sure that the value is valid except in the slightly odd case where | |
4251 | -- the expression is a reference to a variable whose size has been | |
4252 | -- explicitly set to a value greater than the object size. | |
ee6ba406 | 4253 | |
4254 | elsif Is_Known_Valid (Typ) then | |
4255 | if Is_Entity_Name (Expr) | |
4256 | and then Ekind (Entity (Expr)) = E_Variable | |
4257 | and then Esize (Entity (Expr)) > Esize (Typ) | |
4258 | then | |
4259 | return False; | |
4260 | else | |
4261 | return True; | |
4262 | end if; | |
4263 | ||
4264 | -- Integer and character literals always have valid values, where | |
4265 | -- appropriate these will be range checked in any case. | |
4266 | ||
4267 | elsif Nkind (Expr) = N_Integer_Literal | |
4268 | or else | |
4269 | Nkind (Expr) = N_Character_Literal | |
4270 | then | |
4271 | return True; | |
4272 | ||
4273 | -- If we have a type conversion or a qualification of a known valid | |
4274 | -- value, then the result will always be valid. | |
4275 | ||
4276 | elsif Nkind (Expr) = N_Type_Conversion | |
4277 | or else | |
4278 | Nkind (Expr) = N_Qualified_Expression | |
4279 | then | |
4280 | return Expr_Known_Valid (Expression (Expr)); | |
4281 | ||
38f5559f | 4282 | -- The result of any operator is always considered valid, since we |
4283 | -- assume the necessary checks are done by the operator. For operators | |
4284 | -- on floating-point operations, we must also check when the operation | |
4285 | -- is the right-hand side of an assignment, or is an actual in a call. | |
ee6ba406 | 4286 | |
0577b0b1 | 4287 | elsif Nkind (Expr) in N_Op then |
1d90d657 | 4288 | if Is_Floating_Point_Type (Typ) |
4289 | and then Validity_Check_Floating_Point | |
4290 | and then | |
4291 | (Nkind (Parent (Expr)) = N_Assignment_Statement | |
4292 | or else Nkind (Parent (Expr)) = N_Function_Call | |
4293 | or else Nkind (Parent (Expr)) = N_Parameter_Association) | |
4294 | then | |
4295 | return False; | |
4296 | else | |
4297 | return True; | |
4298 | end if; | |
4299 | ||
feff2f05 | 4300 | -- The result of a membership test is always valid, since it is true or |
4301 | -- false, there are no other possibilities. | |
0577b0b1 | 4302 | |
4303 | elsif Nkind (Expr) in N_Membership_Test then | |
4304 | return True; | |
4305 | ||
ee6ba406 | 4306 | -- For all other cases, we do not know the expression is valid |
4307 | ||
4308 | else | |
4309 | return False; | |
4310 | end if; | |
4311 | end Expr_Known_Valid; | |
4312 | ||
9dfe12ae | 4313 | ---------------- |
4314 | -- Find_Check -- | |
4315 | ---------------- | |
4316 | ||
4317 | procedure Find_Check | |
4318 | (Expr : Node_Id; | |
4319 | Check_Type : Character; | |
4320 | Target_Type : Entity_Id; | |
4321 | Entry_OK : out Boolean; | |
4322 | Check_Num : out Nat; | |
4323 | Ent : out Entity_Id; | |
4324 | Ofs : out Uint) | |
4325 | is | |
4326 | function Within_Range_Of | |
4327 | (Target_Type : Entity_Id; | |
314a23b6 | 4328 | Check_Type : Entity_Id) return Boolean; |
9dfe12ae | 4329 | -- Given a requirement for checking a range against Target_Type, and |
4330 | -- and a range Check_Type against which a check has already been made, | |
4331 | -- determines if the check against check type is sufficient to ensure | |
4332 | -- that no check against Target_Type is required. | |
4333 | ||
4334 | --------------------- | |
4335 | -- Within_Range_Of -- | |
4336 | --------------------- | |
4337 | ||
4338 | function Within_Range_Of | |
4339 | (Target_Type : Entity_Id; | |
314a23b6 | 4340 | Check_Type : Entity_Id) return Boolean |
9dfe12ae | 4341 | is |
4342 | begin | |
4343 | if Target_Type = Check_Type then | |
4344 | return True; | |
4345 | ||
4346 | else | |
4347 | declare | |
4348 | Tlo : constant Node_Id := Type_Low_Bound (Target_Type); | |
4349 | Thi : constant Node_Id := Type_High_Bound (Target_Type); | |
4350 | Clo : constant Node_Id := Type_Low_Bound (Check_Type); | |
4351 | Chi : constant Node_Id := Type_High_Bound (Check_Type); | |
4352 | ||
4353 | begin | |
4354 | if (Tlo = Clo | |
4355 | or else (Compile_Time_Known_Value (Tlo) | |
4356 | and then | |
4357 | Compile_Time_Known_Value (Clo) | |
4358 | and then | |
4359 | Expr_Value (Clo) >= Expr_Value (Tlo))) | |
4360 | and then | |
4361 | (Thi = Chi | |
4362 | or else (Compile_Time_Known_Value (Thi) | |
4363 | and then | |
4364 | Compile_Time_Known_Value (Chi) | |
4365 | and then | |
4366 | Expr_Value (Chi) <= Expr_Value (Clo))) | |
4367 | then | |
4368 | return True; | |
4369 | else | |
4370 | return False; | |
4371 | end if; | |
4372 | end; | |
4373 | end if; | |
4374 | end Within_Range_Of; | |
4375 | ||
4376 | -- Start of processing for Find_Check | |
4377 | ||
4378 | begin | |
ed195555 | 4379 | -- Establish default, in case no entry is found |
9dfe12ae | 4380 | |
4381 | Check_Num := 0; | |
4382 | ||
4383 | -- Case of expression is simple entity reference | |
4384 | ||
4385 | if Is_Entity_Name (Expr) then | |
4386 | Ent := Entity (Expr); | |
4387 | Ofs := Uint_0; | |
4388 | ||
4389 | -- Case of expression is entity + known constant | |
4390 | ||
4391 | elsif Nkind (Expr) = N_Op_Add | |
4392 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
4393 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
4394 | then | |
4395 | Ent := Entity (Left_Opnd (Expr)); | |
4396 | Ofs := Expr_Value (Right_Opnd (Expr)); | |
4397 | ||
4398 | -- Case of expression is entity - known constant | |
4399 | ||
4400 | elsif Nkind (Expr) = N_Op_Subtract | |
4401 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
4402 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
4403 | then | |
4404 | Ent := Entity (Left_Opnd (Expr)); | |
4405 | Ofs := UI_Negate (Expr_Value (Right_Opnd (Expr))); | |
4406 | ||
4407 | -- Any other expression is not of the right form | |
4408 | ||
4409 | else | |
4410 | Ent := Empty; | |
4411 | Ofs := Uint_0; | |
4412 | Entry_OK := False; | |
4413 | return; | |
4414 | end if; | |
4415 | ||
feff2f05 | 4416 | -- Come here with expression of appropriate form, check if entity is an |
4417 | -- appropriate one for our purposes. | |
9dfe12ae | 4418 | |
4419 | if (Ekind (Ent) = E_Variable | |
cc60bd16 | 4420 | or else Is_Constant_Object (Ent)) |
9dfe12ae | 4421 | and then not Is_Library_Level_Entity (Ent) |
4422 | then | |
4423 | Entry_OK := True; | |
4424 | else | |
4425 | Entry_OK := False; | |
4426 | return; | |
4427 | end if; | |
4428 | ||
4429 | -- See if there is matching check already | |
4430 | ||
4431 | for J in reverse 1 .. Num_Saved_Checks loop | |
4432 | declare | |
4433 | SC : Saved_Check renames Saved_Checks (J); | |
4434 | ||
4435 | begin | |
4436 | if SC.Killed = False | |
4437 | and then SC.Entity = Ent | |
4438 | and then SC.Offset = Ofs | |
4439 | and then SC.Check_Type = Check_Type | |
4440 | and then Within_Range_Of (Target_Type, SC.Target_Type) | |
4441 | then | |
4442 | Check_Num := J; | |
4443 | return; | |
4444 | end if; | |
4445 | end; | |
4446 | end loop; | |
4447 | ||
4448 | -- If we fall through entry was not found | |
4449 | ||
9dfe12ae | 4450 | return; |
4451 | end Find_Check; | |
4452 | ||
4453 | --------------------------------- | |
4454 | -- Generate_Discriminant_Check -- | |
4455 | --------------------------------- | |
4456 | ||
4457 | -- Note: the code for this procedure is derived from the | |
feff2f05 | 4458 | -- Emit_Discriminant_Check Routine in trans.c. |
9dfe12ae | 4459 | |
4460 | procedure Generate_Discriminant_Check (N : Node_Id) is | |
4461 | Loc : constant Source_Ptr := Sloc (N); | |
4462 | Pref : constant Node_Id := Prefix (N); | |
4463 | Sel : constant Node_Id := Selector_Name (N); | |
4464 | ||
4465 | Orig_Comp : constant Entity_Id := | |
4466 | Original_Record_Component (Entity (Sel)); | |
4467 | -- The original component to be checked | |
4468 | ||
4469 | Discr_Fct : constant Entity_Id := | |
4470 | Discriminant_Checking_Func (Orig_Comp); | |
4471 | -- The discriminant checking function | |
4472 | ||
4473 | Discr : Entity_Id; | |
4474 | -- One discriminant to be checked in the type | |
4475 | ||
4476 | Real_Discr : Entity_Id; | |
4477 | -- Actual discriminant in the call | |
4478 | ||
4479 | Pref_Type : Entity_Id; | |
4480 | -- Type of relevant prefix (ignoring private/access stuff) | |
4481 | ||
4482 | Args : List_Id; | |
4483 | -- List of arguments for function call | |
4484 | ||
4485 | Formal : Entity_Id; | |
feff2f05 | 4486 | -- Keep track of the formal corresponding to the actual we build for |
4487 | -- each discriminant, in order to be able to perform the necessary type | |
4488 | -- conversions. | |
9dfe12ae | 4489 | |
4490 | Scomp : Node_Id; | |
4491 | -- Selected component reference for checking function argument | |
4492 | ||
4493 | begin | |
4494 | Pref_Type := Etype (Pref); | |
4495 | ||
4496 | -- Force evaluation of the prefix, so that it does not get evaluated | |
4497 | -- twice (once for the check, once for the actual reference). Such a | |
4498 | -- double evaluation is always a potential source of inefficiency, | |
4499 | -- and is functionally incorrect in the volatile case, or when the | |
4500 | -- prefix may have side-effects. An entity or a component of an | |
4501 | -- entity requires no evaluation. | |
4502 | ||
4503 | if Is_Entity_Name (Pref) then | |
4504 | if Treat_As_Volatile (Entity (Pref)) then | |
4505 | Force_Evaluation (Pref, Name_Req => True); | |
4506 | end if; | |
4507 | ||
4508 | elsif Treat_As_Volatile (Etype (Pref)) then | |
4509 | Force_Evaluation (Pref, Name_Req => True); | |
4510 | ||
4511 | elsif Nkind (Pref) = N_Selected_Component | |
4512 | and then Is_Entity_Name (Prefix (Pref)) | |
4513 | then | |
4514 | null; | |
4515 | ||
4516 | else | |
4517 | Force_Evaluation (Pref, Name_Req => True); | |
4518 | end if; | |
4519 | ||
4520 | -- For a tagged type, use the scope of the original component to | |
4521 | -- obtain the type, because ??? | |
4522 | ||
4523 | if Is_Tagged_Type (Scope (Orig_Comp)) then | |
4524 | Pref_Type := Scope (Orig_Comp); | |
4525 | ||
feff2f05 | 4526 | -- For an untagged derived type, use the discriminants of the parent |
4527 | -- which have been renamed in the derivation, possibly by a one-to-many | |
4528 | -- discriminant constraint. For non-tagged type, initially get the Etype | |
4529 | -- of the prefix | |
9dfe12ae | 4530 | |
4531 | else | |
4532 | if Is_Derived_Type (Pref_Type) | |
4533 | and then Number_Discriminants (Pref_Type) /= | |
4534 | Number_Discriminants (Etype (Base_Type (Pref_Type))) | |
4535 | then | |
4536 | Pref_Type := Etype (Base_Type (Pref_Type)); | |
4537 | end if; | |
4538 | end if; | |
4539 | ||
4540 | -- We definitely should have a checking function, This routine should | |
4541 | -- not be called if no discriminant checking function is present. | |
4542 | ||
4543 | pragma Assert (Present (Discr_Fct)); | |
4544 | ||
4545 | -- Create the list of the actual parameters for the call. This list | |
4546 | -- is the list of the discriminant fields of the record expression to | |
4547 | -- be discriminant checked. | |
4548 | ||
4549 | Args := New_List; | |
4550 | Formal := First_Formal (Discr_Fct); | |
4551 | Discr := First_Discriminant (Pref_Type); | |
4552 | while Present (Discr) loop | |
4553 | ||
4554 | -- If we have a corresponding discriminant field, and a parent | |
4555 | -- subtype is present, then we want to use the corresponding | |
4556 | -- discriminant since this is the one with the useful value. | |
4557 | ||
4558 | if Present (Corresponding_Discriminant (Discr)) | |
4559 | and then Ekind (Pref_Type) = E_Record_Type | |
4560 | and then Present (Parent_Subtype (Pref_Type)) | |
4561 | then | |
4562 | Real_Discr := Corresponding_Discriminant (Discr); | |
4563 | else | |
4564 | Real_Discr := Discr; | |
4565 | end if; | |
4566 | ||
4567 | -- Construct the reference to the discriminant | |
4568 | ||
4569 | Scomp := | |
4570 | Make_Selected_Component (Loc, | |
4571 | Prefix => | |
4572 | Unchecked_Convert_To (Pref_Type, | |
4573 | Duplicate_Subexpr (Pref)), | |
4574 | Selector_Name => New_Occurrence_Of (Real_Discr, Loc)); | |
4575 | ||
4576 | -- Manually analyze and resolve this selected component. We really | |
4577 | -- want it just as it appears above, and do not want the expander | |
feff2f05 | 4578 | -- playing discriminal games etc with this reference. Then we append |
4579 | -- the argument to the list we are gathering. | |
9dfe12ae | 4580 | |
4581 | Set_Etype (Scomp, Etype (Real_Discr)); | |
4582 | Set_Analyzed (Scomp, True); | |
4583 | Append_To (Args, Convert_To (Etype (Formal), Scomp)); | |
4584 | ||
4585 | Next_Formal_With_Extras (Formal); | |
4586 | Next_Discriminant (Discr); | |
4587 | end loop; | |
4588 | ||
4589 | -- Now build and insert the call | |
4590 | ||
4591 | Insert_Action (N, | |
4592 | Make_Raise_Constraint_Error (Loc, | |
4593 | Condition => | |
4594 | Make_Function_Call (Loc, | |
4595 | Name => New_Occurrence_Of (Discr_Fct, Loc), | |
4596 | Parameter_Associations => Args), | |
4597 | Reason => CE_Discriminant_Check_Failed)); | |
4598 | end Generate_Discriminant_Check; | |
4599 | ||
5c99c290 | 4600 | --------------------------- |
4601 | -- Generate_Index_Checks -- | |
4602 | --------------------------- | |
9dfe12ae | 4603 | |
4604 | procedure Generate_Index_Checks (N : Node_Id) is | |
05f3e139 | 4605 | |
4606 | function Entity_Of_Prefix return Entity_Id; | |
4607 | -- Returns the entity of the prefix of N (or Empty if not found) | |
4608 | ||
3f42e2a7 | 4609 | ---------------------- |
4610 | -- Entity_Of_Prefix -- | |
4611 | ---------------------- | |
4612 | ||
05f3e139 | 4613 | function Entity_Of_Prefix return Entity_Id is |
e5d38095 | 4614 | P : Node_Id; |
4615 | ||
05f3e139 | 4616 | begin |
e5d38095 | 4617 | P := Prefix (N); |
05f3e139 | 4618 | while not Is_Entity_Name (P) loop |
4619 | if not Nkind_In (P, N_Selected_Component, | |
4620 | N_Indexed_Component) | |
4621 | then | |
4622 | return Empty; | |
4623 | end if; | |
4624 | ||
4625 | P := Prefix (P); | |
4626 | end loop; | |
4627 | ||
4628 | return Entity (P); | |
4629 | end Entity_Of_Prefix; | |
4630 | ||
4631 | -- Local variables | |
4632 | ||
4633 | Loc : constant Source_Ptr := Sloc (N); | |
4634 | A : constant Node_Id := Prefix (N); | |
4635 | A_Ent : constant Entity_Id := Entity_Of_Prefix; | |
4636 | Sub : Node_Id; | |
9dfe12ae | 4637 | |
3f42e2a7 | 4638 | -- Start of processing for Generate_Index_Checks |
4639 | ||
9dfe12ae | 4640 | begin |
05f3e139 | 4641 | -- Ignore call if the prefix is not an array since we have a serious |
4642 | -- error in the sources. Ignore it also if index checks are suppressed | |
4643 | -- for array object or type. | |
0577b0b1 | 4644 | |
05f3e139 | 4645 | if not Is_Array_Type (Etype (A)) |
4646 | or else (Present (A_Ent) | |
e5d38095 | 4647 | and then Index_Checks_Suppressed (A_Ent)) |
0577b0b1 | 4648 | or else Index_Checks_Suppressed (Etype (A)) |
4649 | then | |
4650 | return; | |
4651 | end if; | |
4652 | ||
05f3e139 | 4653 | -- Generate a raise of constraint error with the appropriate reason and |
4654 | -- a condition of the form: | |
4655 | ||
3f42e2a7 | 4656 | -- Base_Type (Sub) not in Array'Range (Subscript) |
05f3e139 | 4657 | |
4658 | -- Note that the reason we generate the conversion to the base type here | |
4659 | -- is that we definitely want the range check to take place, even if it | |
4660 | -- looks like the subtype is OK. Optimization considerations that allow | |
4661 | -- us to omit the check have already been taken into account in the | |
4662 | -- setting of the Do_Range_Check flag earlier on. | |
0577b0b1 | 4663 | |
9dfe12ae | 4664 | Sub := First (Expressions (N)); |
05f3e139 | 4665 | |
4666 | -- Handle string literals | |
4667 | ||
4668 | if Ekind (Etype (A)) = E_String_Literal_Subtype then | |
9dfe12ae | 4669 | if Do_Range_Check (Sub) then |
4670 | Set_Do_Range_Check (Sub, False); | |
4671 | ||
05f3e139 | 4672 | -- For string literals we obtain the bounds of the string from the |
4673 | -- associated subtype. | |
9dfe12ae | 4674 | |
05f3e139 | 4675 | Insert_Action (N, |
4676 | Make_Raise_Constraint_Error (Loc, | |
4677 | Condition => | |
4678 | Make_Not_In (Loc, | |
4679 | Left_Opnd => | |
4680 | Convert_To (Base_Type (Etype (Sub)), | |
4681 | Duplicate_Subexpr_Move_Checks (Sub)), | |
4682 | Right_Opnd => | |
4683 | Make_Attribute_Reference (Loc, | |
3f42e2a7 | 4684 | Prefix => New_Reference_To (Etype (A), Loc), |
05f3e139 | 4685 | Attribute_Name => Name_Range)), |
4686 | Reason => CE_Index_Check_Failed)); | |
4687 | end if; | |
9dfe12ae | 4688 | |
05f3e139 | 4689 | -- General case |
9dfe12ae | 4690 | |
05f3e139 | 4691 | else |
4692 | declare | |
4693 | A_Idx : Node_Id := Empty; | |
4694 | A_Range : Node_Id; | |
4695 | Ind : Nat; | |
4696 | Num : List_Id; | |
4697 | Range_N : Node_Id; | |
9dfe12ae | 4698 | |
05f3e139 | 4699 | begin |
4700 | A_Idx := First_Index (Etype (A)); | |
4701 | Ind := 1; | |
4702 | while Present (Sub) loop | |
4703 | if Do_Range_Check (Sub) then | |
4704 | Set_Do_Range_Check (Sub, False); | |
9dfe12ae | 4705 | |
05f3e139 | 4706 | -- Force evaluation except for the case of a simple name of |
4707 | -- a non-volatile entity. | |
9dfe12ae | 4708 | |
05f3e139 | 4709 | if not Is_Entity_Name (Sub) |
4710 | or else Treat_As_Volatile (Entity (Sub)) | |
4711 | then | |
4712 | Force_Evaluation (Sub); | |
4713 | end if; | |
9dfe12ae | 4714 | |
05f3e139 | 4715 | if Nkind (A_Idx) = N_Range then |
4716 | A_Range := A_Idx; | |
4717 | ||
4718 | elsif Nkind (A_Idx) = N_Identifier | |
4719 | or else Nkind (A_Idx) = N_Expanded_Name | |
4720 | then | |
4721 | A_Range := Scalar_Range (Entity (A_Idx)); | |
4722 | ||
4723 | else pragma Assert (Nkind (A_Idx) = N_Subtype_Indication); | |
4724 | A_Range := Range_Expression (Constraint (A_Idx)); | |
4725 | end if; | |
4726 | ||
4727 | -- For array objects with constant bounds we can generate | |
4728 | -- the index check using the bounds of the type of the index | |
4729 | ||
4730 | if Present (A_Ent) | |
4731 | and then Ekind (A_Ent) = E_Variable | |
4732 | and then Is_Constant_Bound (Low_Bound (A_Range)) | |
4733 | and then Is_Constant_Bound (High_Bound (A_Range)) | |
4734 | then | |
4735 | Range_N := | |
4736 | Make_Attribute_Reference (Loc, | |
3f42e2a7 | 4737 | Prefix => |
4738 | New_Reference_To (Etype (A_Idx), Loc), | |
05f3e139 | 4739 | Attribute_Name => Name_Range); |
4740 | ||
4741 | -- For arrays with non-constant bounds we cannot generate | |
4742 | -- the index check using the bounds of the type of the index | |
4743 | -- since it may reference discriminants of some enclosing | |
4744 | -- type. We obtain the bounds directly from the prefix | |
4745 | -- object. | |
4746 | ||
4747 | else | |
4748 | if Ind = 1 then | |
4749 | Num := No_List; | |
4750 | else | |
4751 | Num := New_List (Make_Integer_Literal (Loc, Ind)); | |
4752 | end if; | |
4753 | ||
4754 | Range_N := | |
4755 | Make_Attribute_Reference (Loc, | |
4756 | Prefix => | |
4757 | Duplicate_Subexpr_Move_Checks (A, Name_Req => True), | |
4758 | Attribute_Name => Name_Range, | |
4759 | Expressions => Num); | |
4760 | end if; | |
4761 | ||
4762 | Insert_Action (N, | |
4763 | Make_Raise_Constraint_Error (Loc, | |
4764 | Condition => | |
4765 | Make_Not_In (Loc, | |
4766 | Left_Opnd => | |
4767 | Convert_To (Base_Type (Etype (Sub)), | |
4768 | Duplicate_Subexpr_Move_Checks (Sub)), | |
4769 | Right_Opnd => Range_N), | |
4770 | Reason => CE_Index_Check_Failed)); | |
4771 | end if; | |
4772 | ||
4773 | A_Idx := Next_Index (A_Idx); | |
4774 | Ind := Ind + 1; | |
4775 | Next (Sub); | |
4776 | end loop; | |
4777 | end; | |
4778 | end if; | |
9dfe12ae | 4779 | end Generate_Index_Checks; |
4780 | ||
4781 | -------------------------- | |
4782 | -- Generate_Range_Check -- | |
4783 | -------------------------- | |
4784 | ||
4785 | procedure Generate_Range_Check | |
4786 | (N : Node_Id; | |
4787 | Target_Type : Entity_Id; | |
4788 | Reason : RT_Exception_Code) | |
4789 | is | |
4790 | Loc : constant Source_Ptr := Sloc (N); | |
4791 | Source_Type : constant Entity_Id := Etype (N); | |
4792 | Source_Base_Type : constant Entity_Id := Base_Type (Source_Type); | |
4793 | Target_Base_Type : constant Entity_Id := Base_Type (Target_Type); | |
4794 | ||
4795 | begin | |
feff2f05 | 4796 | -- First special case, if the source type is already within the range |
4797 | -- of the target type, then no check is needed (probably we should have | |
4798 | -- stopped Do_Range_Check from being set in the first place, but better | |
4799 | -- late than later in preventing junk code! | |
9dfe12ae | 4800 | |
feff2f05 | 4801 | -- We do NOT apply this if the source node is a literal, since in this |
4802 | -- case the literal has already been labeled as having the subtype of | |
4803 | -- the target. | |
9dfe12ae | 4804 | |
7a1dabb3 | 4805 | if In_Subrange_Of (Source_Type, Target_Type) |
9dfe12ae | 4806 | and then not |
4807 | (Nkind (N) = N_Integer_Literal | |
4808 | or else | |
4809 | Nkind (N) = N_Real_Literal | |
4810 | or else | |
4811 | Nkind (N) = N_Character_Literal | |
4812 | or else | |
4813 | (Is_Entity_Name (N) | |
4814 | and then Ekind (Entity (N)) = E_Enumeration_Literal)) | |
4815 | then | |
4816 | return; | |
4817 | end if; | |
4818 | ||
4819 | -- We need a check, so force evaluation of the node, so that it does | |
4820 | -- not get evaluated twice (once for the check, once for the actual | |
4821 | -- reference). Such a double evaluation is always a potential source | |
4822 | -- of inefficiency, and is functionally incorrect in the volatile case. | |
4823 | ||
4824 | if not Is_Entity_Name (N) | |
4825 | or else Treat_As_Volatile (Entity (N)) | |
4826 | then | |
4827 | Force_Evaluation (N); | |
4828 | end if; | |
4829 | ||
feff2f05 | 4830 | -- The easiest case is when Source_Base_Type and Target_Base_Type are |
4831 | -- the same since in this case we can simply do a direct check of the | |
4832 | -- value of N against the bounds of Target_Type. | |
9dfe12ae | 4833 | |
4834 | -- [constraint_error when N not in Target_Type] | |
4835 | ||
4836 | -- Note: this is by far the most common case, for example all cases of | |
4837 | -- checks on the RHS of assignments are in this category, but not all | |
4838 | -- cases are like this. Notably conversions can involve two types. | |
4839 | ||
4840 | if Source_Base_Type = Target_Base_Type then | |
4841 | Insert_Action (N, | |
4842 | Make_Raise_Constraint_Error (Loc, | |
4843 | Condition => | |
4844 | Make_Not_In (Loc, | |
4845 | Left_Opnd => Duplicate_Subexpr (N), | |
4846 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
4847 | Reason => Reason)); | |
4848 | ||
4849 | -- Next test for the case where the target type is within the bounds | |
4850 | -- of the base type of the source type, since in this case we can | |
4851 | -- simply convert these bounds to the base type of T to do the test. | |
4852 | ||
4853 | -- [constraint_error when N not in | |
4854 | -- Source_Base_Type (Target_Type'First) | |
4855 | -- .. | |
4856 | -- Source_Base_Type(Target_Type'Last))] | |
4857 | ||
f2a06be9 | 4858 | -- The conversions will always work and need no check |
9dfe12ae | 4859 | |
a9b57347 | 4860 | -- Unchecked_Convert_To is used instead of Convert_To to handle the case |
4861 | -- of converting from an enumeration value to an integer type, such as | |
4862 | -- occurs for the case of generating a range check on Enum'Val(Exp) | |
4863 | -- (which used to be handled by gigi). This is OK, since the conversion | |
4864 | -- itself does not require a check. | |
4865 | ||
7a1dabb3 | 4866 | elsif In_Subrange_Of (Target_Type, Source_Base_Type) then |
9dfe12ae | 4867 | Insert_Action (N, |
4868 | Make_Raise_Constraint_Error (Loc, | |
4869 | Condition => | |
4870 | Make_Not_In (Loc, | |
4871 | Left_Opnd => Duplicate_Subexpr (N), | |
4872 | ||
4873 | Right_Opnd => | |
4874 | Make_Range (Loc, | |
4875 | Low_Bound => | |
a9b57347 | 4876 | Unchecked_Convert_To (Source_Base_Type, |
9dfe12ae | 4877 | Make_Attribute_Reference (Loc, |
4878 | Prefix => | |
4879 | New_Occurrence_Of (Target_Type, Loc), | |
4880 | Attribute_Name => Name_First)), | |
4881 | ||
4882 | High_Bound => | |
a9b57347 | 4883 | Unchecked_Convert_To (Source_Base_Type, |
9dfe12ae | 4884 | Make_Attribute_Reference (Loc, |
4885 | Prefix => | |
4886 | New_Occurrence_Of (Target_Type, Loc), | |
4887 | Attribute_Name => Name_Last)))), | |
4888 | Reason => Reason)); | |
4889 | ||
feff2f05 | 4890 | -- Note that at this stage we now that the Target_Base_Type is not in |
4891 | -- the range of the Source_Base_Type (since even the Target_Type itself | |
4892 | -- is not in this range). It could still be the case that Source_Type is | |
4893 | -- in range of the target base type since we have not checked that case. | |
9dfe12ae | 4894 | |
feff2f05 | 4895 | -- If that is the case, we can freely convert the source to the target, |
4896 | -- and then test the target result against the bounds. | |
9dfe12ae | 4897 | |
7a1dabb3 | 4898 | elsif In_Subrange_Of (Source_Type, Target_Base_Type) then |
9dfe12ae | 4899 | |
feff2f05 | 4900 | -- We make a temporary to hold the value of the converted value |
4901 | -- (converted to the base type), and then we will do the test against | |
4902 | -- this temporary. | |
9dfe12ae | 4903 | |
4904 | -- Tnn : constant Target_Base_Type := Target_Base_Type (N); | |
4905 | -- [constraint_error when Tnn not in Target_Type] | |
4906 | ||
4907 | -- Then the conversion itself is replaced by an occurrence of Tnn | |
4908 | ||
4909 | declare | |
46eb6933 | 4910 | Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
9dfe12ae | 4911 | |
4912 | begin | |
4913 | Insert_Actions (N, New_List ( | |
4914 | Make_Object_Declaration (Loc, | |
4915 | Defining_Identifier => Tnn, | |
4916 | Object_Definition => | |
4917 | New_Occurrence_Of (Target_Base_Type, Loc), | |
4918 | Constant_Present => True, | |
4919 | Expression => | |
4920 | Make_Type_Conversion (Loc, | |
4921 | Subtype_Mark => New_Occurrence_Of (Target_Base_Type, Loc), | |
4922 | Expression => Duplicate_Subexpr (N))), | |
4923 | ||
4924 | Make_Raise_Constraint_Error (Loc, | |
4925 | Condition => | |
4926 | Make_Not_In (Loc, | |
4927 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
4928 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
4929 | ||
4930 | Reason => Reason))); | |
4931 | ||
4932 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
2af58f67 | 4933 | |
4934 | -- Set the type of N, because the declaration for Tnn might not | |
4935 | -- be analyzed yet, as is the case if N appears within a record | |
4936 | -- declaration, as a discriminant constraint or expression. | |
4937 | ||
4938 | Set_Etype (N, Target_Base_Type); | |
9dfe12ae | 4939 | end; |
4940 | ||
4941 | -- At this stage, we know that we have two scalar types, which are | |
4942 | -- directly convertible, and where neither scalar type has a base | |
4943 | -- range that is in the range of the other scalar type. | |
4944 | ||
4945 | -- The only way this can happen is with a signed and unsigned type. | |
4946 | -- So test for these two cases: | |
4947 | ||
4948 | else | |
4949 | -- Case of the source is unsigned and the target is signed | |
4950 | ||
4951 | if Is_Unsigned_Type (Source_Base_Type) | |
4952 | and then not Is_Unsigned_Type (Target_Base_Type) | |
4953 | then | |
4954 | -- If the source is unsigned and the target is signed, then we | |
4955 | -- know that the source is not shorter than the target (otherwise | |
4956 | -- the source base type would be in the target base type range). | |
4957 | ||
feff2f05 | 4958 | -- In other words, the unsigned type is either the same size as |
4959 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 4960 | |
4961 | pragma Assert | |
4962 | (Esize (Source_Base_Type) >= Esize (Target_Base_Type)); | |
4963 | ||
4964 | -- We only need to check the low bound if the low bound of the | |
4965 | -- target type is non-negative. If the low bound of the target | |
4966 | -- type is negative, then we know that we will fit fine. | |
4967 | ||
4968 | -- If the high bound of the target type is negative, then we | |
4969 | -- know we have a constraint error, since we can't possibly | |
4970 | -- have a negative source. | |
4971 | ||
4972 | -- With these two checks out of the way, we can do the check | |
4973 | -- using the source type safely | |
4974 | ||
4975 | -- This is definitely the most annoying case! | |
4976 | ||
4977 | -- [constraint_error | |
4978 | -- when (Target_Type'First >= 0 | |
4979 | -- and then | |
4980 | -- N < Source_Base_Type (Target_Type'First)) | |
4981 | -- or else Target_Type'Last < 0 | |
4982 | -- or else N > Source_Base_Type (Target_Type'Last)]; | |
4983 | ||
4984 | -- We turn off all checks since we know that the conversions | |
4985 | -- will work fine, given the guards for negative values. | |
4986 | ||
4987 | Insert_Action (N, | |
4988 | Make_Raise_Constraint_Error (Loc, | |
4989 | Condition => | |
4990 | Make_Or_Else (Loc, | |
4991 | Make_Or_Else (Loc, | |
4992 | Left_Opnd => | |
4993 | Make_And_Then (Loc, | |
4994 | Left_Opnd => Make_Op_Ge (Loc, | |
4995 | Left_Opnd => | |
4996 | Make_Attribute_Reference (Loc, | |
4997 | Prefix => | |
4998 | New_Occurrence_Of (Target_Type, Loc), | |
4999 | Attribute_Name => Name_First), | |
5000 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
5001 | ||
5002 | Right_Opnd => | |
5003 | Make_Op_Lt (Loc, | |
5004 | Left_Opnd => Duplicate_Subexpr (N), | |
5005 | Right_Opnd => | |
5006 | Convert_To (Source_Base_Type, | |
5007 | Make_Attribute_Reference (Loc, | |
5008 | Prefix => | |
5009 | New_Occurrence_Of (Target_Type, Loc), | |
5010 | Attribute_Name => Name_First)))), | |
5011 | ||
5012 | Right_Opnd => | |
5013 | Make_Op_Lt (Loc, | |
5014 | Left_Opnd => | |
5015 | Make_Attribute_Reference (Loc, | |
5016 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
5017 | Attribute_Name => Name_Last), | |
5018 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0))), | |
5019 | ||
5020 | Right_Opnd => | |
5021 | Make_Op_Gt (Loc, | |
5022 | Left_Opnd => Duplicate_Subexpr (N), | |
5023 | Right_Opnd => | |
5024 | Convert_To (Source_Base_Type, | |
5025 | Make_Attribute_Reference (Loc, | |
5026 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
5027 | Attribute_Name => Name_Last)))), | |
5028 | ||
5029 | Reason => Reason), | |
5030 | Suppress => All_Checks); | |
5031 | ||
5032 | -- Only remaining possibility is that the source is signed and | |
fc75802a | 5033 | -- the target is unsigned. |
9dfe12ae | 5034 | |
5035 | else | |
5036 | pragma Assert (not Is_Unsigned_Type (Source_Base_Type) | |
5037 | and then Is_Unsigned_Type (Target_Base_Type)); | |
5038 | ||
feff2f05 | 5039 | -- If the source is signed and the target is unsigned, then we |
5040 | -- know that the target is not shorter than the source (otherwise | |
5041 | -- the target base type would be in the source base type range). | |
9dfe12ae | 5042 | |
feff2f05 | 5043 | -- In other words, the unsigned type is either the same size as |
5044 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 5045 | |
feff2f05 | 5046 | -- Clearly we have an error if the source value is negative since |
5047 | -- no unsigned type can have negative values. If the source type | |
5048 | -- is non-negative, then the check can be done using the target | |
5049 | -- type. | |
9dfe12ae | 5050 | |
5051 | -- Tnn : constant Target_Base_Type (N) := Target_Type; | |
5052 | ||
5053 | -- [constraint_error | |
5054 | -- when N < 0 or else Tnn not in Target_Type]; | |
5055 | ||
feff2f05 | 5056 | -- We turn off all checks for the conversion of N to the target |
5057 | -- base type, since we generate the explicit check to ensure that | |
5058 | -- the value is non-negative | |
9dfe12ae | 5059 | |
5060 | declare | |
46eb6933 | 5061 | Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
9dfe12ae | 5062 | |
5063 | begin | |
5064 | Insert_Actions (N, New_List ( | |
5065 | Make_Object_Declaration (Loc, | |
5066 | Defining_Identifier => Tnn, | |
5067 | Object_Definition => | |
5068 | New_Occurrence_Of (Target_Base_Type, Loc), | |
5069 | Constant_Present => True, | |
5070 | Expression => | |
a9b57347 | 5071 | Make_Unchecked_Type_Conversion (Loc, |
9dfe12ae | 5072 | Subtype_Mark => |
5073 | New_Occurrence_Of (Target_Base_Type, Loc), | |
5074 | Expression => Duplicate_Subexpr (N))), | |
5075 | ||
5076 | Make_Raise_Constraint_Error (Loc, | |
5077 | Condition => | |
5078 | Make_Or_Else (Loc, | |
5079 | Left_Opnd => | |
5080 | Make_Op_Lt (Loc, | |
5081 | Left_Opnd => Duplicate_Subexpr (N), | |
5082 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
5083 | ||
5084 | Right_Opnd => | |
5085 | Make_Not_In (Loc, | |
5086 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
5087 | Right_Opnd => | |
5088 | New_Occurrence_Of (Target_Type, Loc))), | |
5089 | ||
5090 | Reason => Reason)), | |
5091 | Suppress => All_Checks); | |
5092 | ||
feff2f05 | 5093 | -- Set the Etype explicitly, because Insert_Actions may have |
5094 | -- placed the declaration in the freeze list for an enclosing | |
5095 | -- construct, and thus it is not analyzed yet. | |
9dfe12ae | 5096 | |
5097 | Set_Etype (Tnn, Target_Base_Type); | |
5098 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
5099 | end; | |
5100 | end if; | |
5101 | end if; | |
5102 | end Generate_Range_Check; | |
5103 | ||
2af58f67 | 5104 | ------------------ |
5105 | -- Get_Check_Id -- | |
5106 | ------------------ | |
5107 | ||
5108 | function Get_Check_Id (N : Name_Id) return Check_Id is | |
5109 | begin | |
5110 | -- For standard check name, we can do a direct computation | |
5111 | ||
5112 | if N in First_Check_Name .. Last_Check_Name then | |
5113 | return Check_Id (N - (First_Check_Name - 1)); | |
5114 | ||
5115 | -- For non-standard names added by pragma Check_Name, search table | |
5116 | ||
5117 | else | |
5118 | for J in All_Checks + 1 .. Check_Names.Last loop | |
5119 | if Check_Names.Table (J) = N then | |
5120 | return J; | |
5121 | end if; | |
5122 | end loop; | |
5123 | end if; | |
5124 | ||
5125 | -- No matching name found | |
5126 | ||
5127 | return No_Check_Id; | |
5128 | end Get_Check_Id; | |
5129 | ||
ee6ba406 | 5130 | --------------------- |
5131 | -- Get_Discriminal -- | |
5132 | --------------------- | |
5133 | ||
5134 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is | |
5135 | Loc : constant Source_Ptr := Sloc (E); | |
5136 | D : Entity_Id; | |
5137 | Sc : Entity_Id; | |
5138 | ||
5139 | begin | |
0577b0b1 | 5140 | -- The bound can be a bona fide parameter of a protected operation, |
5141 | -- rather than a prival encoded as an in-parameter. | |
5142 | ||
5143 | if No (Discriminal_Link (Entity (Bound))) then | |
5144 | return Bound; | |
5145 | end if; | |
5146 | ||
2af58f67 | 5147 | -- Climb the scope stack looking for an enclosing protected type. If |
5148 | -- we run out of scopes, return the bound itself. | |
5149 | ||
5150 | Sc := Scope (E); | |
5151 | while Present (Sc) loop | |
5152 | if Sc = Standard_Standard then | |
5153 | return Bound; | |
5154 | ||
5155 | elsif Ekind (Sc) = E_Protected_Type then | |
5156 | exit; | |
5157 | end if; | |
5158 | ||
5159 | Sc := Scope (Sc); | |
5160 | end loop; | |
5161 | ||
ee6ba406 | 5162 | D := First_Discriminant (Sc); |
2af58f67 | 5163 | while Present (D) loop |
5164 | if Chars (D) = Chars (Bound) then | |
5165 | return New_Occurrence_Of (Discriminal (D), Loc); | |
5166 | end if; | |
ee6ba406 | 5167 | |
ee6ba406 | 5168 | Next_Discriminant (D); |
5169 | end loop; | |
5170 | ||
2af58f67 | 5171 | return Bound; |
ee6ba406 | 5172 | end Get_Discriminal; |
5173 | ||
2af58f67 | 5174 | ---------------------- |
5175 | -- Get_Range_Checks -- | |
5176 | ---------------------- | |
5177 | ||
5178 | function Get_Range_Checks | |
5179 | (Ck_Node : Node_Id; | |
5180 | Target_Typ : Entity_Id; | |
5181 | Source_Typ : Entity_Id := Empty; | |
5182 | Warn_Node : Node_Id := Empty) return Check_Result | |
5183 | is | |
5184 | begin | |
5185 | return Selected_Range_Checks | |
5186 | (Ck_Node, Target_Typ, Source_Typ, Warn_Node); | |
5187 | end Get_Range_Checks; | |
5188 | ||
ee6ba406 | 5189 | ------------------ |
5190 | -- Guard_Access -- | |
5191 | ------------------ | |
5192 | ||
5193 | function Guard_Access | |
5194 | (Cond : Node_Id; | |
5195 | Loc : Source_Ptr; | |
314a23b6 | 5196 | Ck_Node : Node_Id) return Node_Id |
ee6ba406 | 5197 | is |
5198 | begin | |
5199 | if Nkind (Cond) = N_Or_Else then | |
5200 | Set_Paren_Count (Cond, 1); | |
5201 | end if; | |
5202 | ||
5203 | if Nkind (Ck_Node) = N_Allocator then | |
5204 | return Cond; | |
5205 | else | |
5206 | return | |
5207 | Make_And_Then (Loc, | |
5208 | Left_Opnd => | |
5209 | Make_Op_Ne (Loc, | |
9dfe12ae | 5210 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), |
ee6ba406 | 5211 | Right_Opnd => Make_Null (Loc)), |
5212 | Right_Opnd => Cond); | |
5213 | end if; | |
5214 | end Guard_Access; | |
5215 | ||
5216 | ----------------------------- | |
5217 | -- Index_Checks_Suppressed -- | |
5218 | ----------------------------- | |
5219 | ||
5220 | function Index_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5221 | begin | |
9dfe12ae | 5222 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
5223 | return Is_Check_Suppressed (E, Index_Check); | |
5224 | else | |
5225 | return Scope_Suppress (Index_Check); | |
5226 | end if; | |
ee6ba406 | 5227 | end Index_Checks_Suppressed; |
5228 | ||
5229 | ---------------- | |
5230 | -- Initialize -- | |
5231 | ---------------- | |
5232 | ||
5233 | procedure Initialize is | |
5234 | begin | |
5235 | for J in Determine_Range_Cache_N'Range loop | |
5236 | Determine_Range_Cache_N (J) := Empty; | |
5237 | end loop; | |
2af58f67 | 5238 | |
5239 | Check_Names.Init; | |
5240 | ||
5241 | for J in Int range 1 .. All_Checks loop | |
5242 | Check_Names.Append (Name_Id (Int (First_Check_Name) + J - 1)); | |
5243 | end loop; | |
ee6ba406 | 5244 | end Initialize; |
5245 | ||
5246 | ------------------------- | |
5247 | -- Insert_Range_Checks -- | |
5248 | ------------------------- | |
5249 | ||
5250 | procedure Insert_Range_Checks | |
5251 | (Checks : Check_Result; | |
5252 | Node : Node_Id; | |
5253 | Suppress_Typ : Entity_Id; | |
5254 | Static_Sloc : Source_Ptr := No_Location; | |
5255 | Flag_Node : Node_Id := Empty; | |
5256 | Do_Before : Boolean := False) | |
5257 | is | |
5258 | Internal_Flag_Node : Node_Id := Flag_Node; | |
5259 | Internal_Static_Sloc : Source_Ptr := Static_Sloc; | |
5260 | ||
5261 | Check_Node : Node_Id; | |
5262 | Checks_On : constant Boolean := | |
5263 | (not Index_Checks_Suppressed (Suppress_Typ)) | |
5264 | or else | |
5265 | (not Range_Checks_Suppressed (Suppress_Typ)); | |
5266 | ||
5267 | begin | |
feff2f05 | 5268 | -- For now we just return if Checks_On is false, however this should be |
5269 | -- enhanced to check for an always True value in the condition and to | |
5270 | -- generate a compilation warning??? | |
ee6ba406 | 5271 | |
5272 | if not Expander_Active or else not Checks_On then | |
5273 | return; | |
5274 | end if; | |
5275 | ||
5276 | if Static_Sloc = No_Location then | |
5277 | Internal_Static_Sloc := Sloc (Node); | |
5278 | end if; | |
5279 | ||
5280 | if No (Flag_Node) then | |
5281 | Internal_Flag_Node := Node; | |
5282 | end if; | |
5283 | ||
5284 | for J in 1 .. 2 loop | |
5285 | exit when No (Checks (J)); | |
5286 | ||
5287 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
5288 | and then Present (Condition (Checks (J))) | |
5289 | then | |
5290 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
5291 | Check_Node := Checks (J); | |
5292 | Mark_Rewrite_Insertion (Check_Node); | |
5293 | ||
5294 | if Do_Before then | |
5295 | Insert_Before_And_Analyze (Node, Check_Node); | |
5296 | else | |
5297 | Insert_After_And_Analyze (Node, Check_Node); | |
5298 | end if; | |
5299 | ||
5300 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
5301 | end if; | |
5302 | ||
5303 | else | |
5304 | Check_Node := | |
f15731c4 | 5305 | Make_Raise_Constraint_Error (Internal_Static_Sloc, |
5306 | Reason => CE_Range_Check_Failed); | |
ee6ba406 | 5307 | Mark_Rewrite_Insertion (Check_Node); |
5308 | ||
5309 | if Do_Before then | |
5310 | Insert_Before_And_Analyze (Node, Check_Node); | |
5311 | else | |
5312 | Insert_After_And_Analyze (Node, Check_Node); | |
5313 | end if; | |
5314 | end if; | |
5315 | end loop; | |
5316 | end Insert_Range_Checks; | |
5317 | ||
5318 | ------------------------ | |
5319 | -- Insert_Valid_Check -- | |
5320 | ------------------------ | |
5321 | ||
5322 | procedure Insert_Valid_Check (Expr : Node_Id) is | |
5323 | Loc : constant Source_Ptr := Sloc (Expr); | |
8b718dab | 5324 | Exp : Node_Id; |
ee6ba406 | 5325 | |
5326 | begin | |
06ad5813 | 5327 | -- Do not insert if checks off, or if not checking validity or |
5328 | -- if expression is known to be valid | |
ee6ba406 | 5329 | |
0577b0b1 | 5330 | if not Validity_Checks_On |
5331 | or else Range_Or_Validity_Checks_Suppressed (Expr) | |
06ad5813 | 5332 | or else Expr_Known_Valid (Expr) |
ee6ba406 | 5333 | then |
8b718dab | 5334 | return; |
5335 | end if; | |
ee6ba406 | 5336 | |
8b718dab | 5337 | -- If we have a checked conversion, then validity check applies to |
5338 | -- the expression inside the conversion, not the result, since if | |
5339 | -- the expression inside is valid, then so is the conversion result. | |
ee6ba406 | 5340 | |
8b718dab | 5341 | Exp := Expr; |
5342 | while Nkind (Exp) = N_Type_Conversion loop | |
5343 | Exp := Expression (Exp); | |
5344 | end loop; | |
5345 | ||
0577b0b1 | 5346 | -- We are about to insert the validity check for Exp. We save and |
5347 | -- reset the Do_Range_Check flag over this validity check, and then | |
5348 | -- put it back for the final original reference (Exp may be rewritten). | |
5349 | ||
5350 | declare | |
5351 | DRC : constant Boolean := Do_Range_Check (Exp); | |
05fcfafb | 5352 | |
0577b0b1 | 5353 | begin |
5354 | Set_Do_Range_Check (Exp, False); | |
5355 | ||
06ad5813 | 5356 | -- Force evaluation to avoid multiple reads for atomic/volatile |
5357 | ||
5358 | if Is_Entity_Name (Exp) | |
5359 | and then Is_Volatile (Entity (Exp)) | |
5360 | then | |
5361 | Force_Evaluation (Exp, Name_Req => True); | |
5362 | end if; | |
5363 | ||
0577b0b1 | 5364 | -- Insert the validity check. Note that we do this with validity |
5365 | -- checks turned off, to avoid recursion, we do not want validity | |
5366 | -- checks on the validity checking code itself! | |
5367 | ||
5368 | Insert_Action | |
5369 | (Expr, | |
5370 | Make_Raise_Constraint_Error (Loc, | |
5371 | Condition => | |
5372 | Make_Op_Not (Loc, | |
5373 | Right_Opnd => | |
5374 | Make_Attribute_Reference (Loc, | |
5375 | Prefix => | |
5376 | Duplicate_Subexpr_No_Checks (Exp, Name_Req => True), | |
5377 | Attribute_Name => Name_Valid)), | |
5378 | Reason => CE_Invalid_Data), | |
5379 | Suppress => Validity_Check); | |
5380 | ||
6fb3c314 | 5381 | -- If the expression is a reference to an element of a bit-packed |
0577b0b1 | 5382 | -- array, then it is rewritten as a renaming declaration. If the |
5383 | -- expression is an actual in a call, it has not been expanded, | |
5384 | -- waiting for the proper point at which to do it. The same happens | |
5385 | -- with renamings, so that we have to force the expansion now. This | |
5386 | -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb | |
5387 | -- and exp_ch6.adb. | |
5388 | ||
5389 | if Is_Entity_Name (Exp) | |
5390 | and then Nkind (Parent (Entity (Exp))) = | |
5391 | N_Object_Renaming_Declaration | |
5392 | then | |
5393 | declare | |
5394 | Old_Exp : constant Node_Id := Name (Parent (Entity (Exp))); | |
5395 | begin | |
5396 | if Nkind (Old_Exp) = N_Indexed_Component | |
5397 | and then Is_Bit_Packed_Array (Etype (Prefix (Old_Exp))) | |
5398 | then | |
5399 | Expand_Packed_Element_Reference (Old_Exp); | |
5400 | end if; | |
5401 | end; | |
5402 | end if; | |
5403 | ||
5404 | -- Put back the Do_Range_Check flag on the resulting (possibly | |
5405 | -- rewritten) expression. | |
5406 | ||
5407 | -- Note: it might be thought that a validity check is not required | |
5408 | -- when a range check is present, but that's not the case, because | |
5409 | -- the back end is allowed to assume for the range check that the | |
5410 | -- operand is within its declared range (an assumption that validity | |
5411 | -- checking is all about NOT assuming!) | |
5412 | ||
00c403ee | 5413 | -- Note: no need to worry about Possible_Local_Raise here, it will |
5414 | -- already have been called if original node has Do_Range_Check set. | |
5415 | ||
0577b0b1 | 5416 | Set_Do_Range_Check (Exp, DRC); |
5417 | end; | |
ee6ba406 | 5418 | end Insert_Valid_Check; |
5419 | ||
fa7497e8 | 5420 | ---------------------------------- |
5421 | -- Install_Null_Excluding_Check -- | |
5422 | ---------------------------------- | |
5423 | ||
5424 | procedure Install_Null_Excluding_Check (N : Node_Id) is | |
9f294c82 | 5425 | Loc : constant Source_Ptr := Sloc (Parent (N)); |
84d0d4a5 | 5426 | Typ : constant Entity_Id := Etype (N); |
5427 | ||
7b31b357 | 5428 | function Safe_To_Capture_In_Parameter_Value return Boolean; |
5429 | -- Determines if it is safe to capture Known_Non_Null status for an | |
5430 | -- the entity referenced by node N. The caller ensures that N is indeed | |
5431 | -- an entity name. It is safe to capture the non-null status for an IN | |
5432 | -- parameter when the reference occurs within a declaration that is sure | |
5433 | -- to be executed as part of the declarative region. | |
7870823d | 5434 | |
84d0d4a5 | 5435 | procedure Mark_Non_Null; |
7870823d | 5436 | -- After installation of check, if the node in question is an entity |
5437 | -- name, then mark this entity as non-null if possible. | |
5438 | ||
7b31b357 | 5439 | function Safe_To_Capture_In_Parameter_Value return Boolean is |
7870823d | 5440 | E : constant Entity_Id := Entity (N); |
5441 | S : constant Entity_Id := Current_Scope; | |
5442 | S_Par : Node_Id; | |
5443 | ||
5444 | begin | |
7b31b357 | 5445 | if Ekind (E) /= E_In_Parameter then |
5446 | return False; | |
5447 | end if; | |
7870823d | 5448 | |
5449 | -- Two initial context checks. We must be inside a subprogram body | |
5450 | -- with declarations and reference must not appear in nested scopes. | |
5451 | ||
7b31b357 | 5452 | if (Ekind (S) /= E_Function and then Ekind (S) /= E_Procedure) |
7870823d | 5453 | or else Scope (E) /= S |
5454 | then | |
5455 | return False; | |
5456 | end if; | |
5457 | ||
5458 | S_Par := Parent (Parent (S)); | |
5459 | ||
5460 | if Nkind (S_Par) /= N_Subprogram_Body | |
5461 | or else No (Declarations (S_Par)) | |
5462 | then | |
5463 | return False; | |
5464 | end if; | |
5465 | ||
5466 | declare | |
5467 | N_Decl : Node_Id; | |
5468 | P : Node_Id; | |
5469 | ||
5470 | begin | |
5471 | -- Retrieve the declaration node of N (if any). Note that N | |
5472 | -- may be a part of a complex initialization expression. | |
5473 | ||
5474 | P := Parent (N); | |
5475 | N_Decl := Empty; | |
5476 | while Present (P) loop | |
5477 | ||
7b31b357 | 5478 | -- If we have a short circuit form, and we are within the right |
5479 | -- hand expression, we return false, since the right hand side | |
5480 | -- is not guaranteed to be elaborated. | |
5481 | ||
5482 | if Nkind (P) in N_Short_Circuit | |
5483 | and then N = Right_Opnd (P) | |
5484 | then | |
5485 | return False; | |
5486 | end if; | |
5487 | ||
5488 | -- Similarly, if we are in a conditional expression and not | |
5489 | -- part of the condition, then we return False, since neither | |
5490 | -- the THEN or ELSE expressions will always be elaborated. | |
5491 | ||
5492 | if Nkind (P) = N_Conditional_Expression | |
5493 | and then N /= First (Expressions (P)) | |
5494 | then | |
5495 | return False; | |
e977c0cf | 5496 | end if; |
5497 | ||
6fb3c314 | 5498 | -- If we are in a case expression, and not part of the |
e977c0cf | 5499 | -- expression, then we return False, since a particular |
5500 | -- branch may not always be elaborated | |
5501 | ||
5502 | if Nkind (P) = N_Case_Expression | |
5503 | and then N /= Expression (P) | |
5504 | then | |
5505 | return False; | |
7b31b357 | 5506 | end if; |
5507 | ||
7870823d | 5508 | -- While traversing the parent chain, we find that N |
5509 | -- belongs to a statement, thus it may never appear in | |
5510 | -- a declarative region. | |
5511 | ||
5512 | if Nkind (P) in N_Statement_Other_Than_Procedure_Call | |
5513 | or else Nkind (P) = N_Procedure_Call_Statement | |
5514 | then | |
5515 | return False; | |
5516 | end if; | |
5517 | ||
7b31b357 | 5518 | -- If we are at a declaration, record it and exit |
5519 | ||
7870823d | 5520 | if Nkind (P) in N_Declaration |
5521 | and then Nkind (P) not in N_Subprogram_Specification | |
5522 | then | |
5523 | N_Decl := P; | |
5524 | exit; | |
5525 | end if; | |
5526 | ||
5527 | P := Parent (P); | |
5528 | end loop; | |
5529 | ||
5530 | if No (N_Decl) then | |
5531 | return False; | |
5532 | end if; | |
5533 | ||
5534 | return List_Containing (N_Decl) = Declarations (S_Par); | |
5535 | end; | |
7b31b357 | 5536 | end Safe_To_Capture_In_Parameter_Value; |
84d0d4a5 | 5537 | |
5538 | ------------------- | |
5539 | -- Mark_Non_Null -- | |
5540 | ------------------- | |
5541 | ||
5542 | procedure Mark_Non_Null is | |
5543 | begin | |
7870823d | 5544 | -- Only case of interest is if node N is an entity name |
5545 | ||
84d0d4a5 | 5546 | if Is_Entity_Name (N) then |
7870823d | 5547 | |
5548 | -- For sure, we want to clear an indication that this is known to | |
5549 | -- be null, since if we get past this check, it definitely is not! | |
5550 | ||
84d0d4a5 | 5551 | Set_Is_Known_Null (Entity (N), False); |
5552 | ||
7870823d | 5553 | -- We can mark the entity as known to be non-null if either it is |
5554 | -- safe to capture the value, or in the case of an IN parameter, | |
5555 | -- which is a constant, if the check we just installed is in the | |
5556 | -- declarative region of the subprogram body. In this latter case, | |
7b31b357 | 5557 | -- a check is decisive for the rest of the body if the expression |
5558 | -- is sure to be elaborated, since we know we have to elaborate | |
5559 | -- all declarations before executing the body. | |
5560 | ||
5561 | -- Couldn't this always be part of Safe_To_Capture_Value ??? | |
7870823d | 5562 | |
5563 | if Safe_To_Capture_Value (N, Entity (N)) | |
7b31b357 | 5564 | or else Safe_To_Capture_In_Parameter_Value |
7870823d | 5565 | then |
5566 | Set_Is_Known_Non_Null (Entity (N)); | |
84d0d4a5 | 5567 | end if; |
5568 | end if; | |
5569 | end Mark_Non_Null; | |
5570 | ||
5571 | -- Start of processing for Install_Null_Excluding_Check | |
fa7497e8 | 5572 | |
5573 | begin | |
84d0d4a5 | 5574 | pragma Assert (Is_Access_Type (Typ)); |
fa7497e8 | 5575 | |
84d0d4a5 | 5576 | -- No check inside a generic (why not???) |
fa7497e8 | 5577 | |
84d0d4a5 | 5578 | if Inside_A_Generic then |
fa7497e8 | 5579 | return; |
84d0d4a5 | 5580 | end if; |
5581 | ||
5582 | -- No check needed if known to be non-null | |
5583 | ||
5584 | if Known_Non_Null (N) then | |
05fcfafb | 5585 | return; |
84d0d4a5 | 5586 | end if; |
fa7497e8 | 5587 | |
84d0d4a5 | 5588 | -- If known to be null, here is where we generate a compile time check |
5589 | ||
5590 | if Known_Null (N) then | |
d16989f1 | 5591 | |
5592 | -- Avoid generating warning message inside init procs | |
5593 | ||
5594 | if not Inside_Init_Proc then | |
5595 | Apply_Compile_Time_Constraint_Error | |
5596 | (N, | |
5597 | "null value not allowed here?", | |
5598 | CE_Access_Check_Failed); | |
5599 | else | |
5600 | Insert_Action (N, | |
5601 | Make_Raise_Constraint_Error (Loc, | |
5602 | Reason => CE_Access_Check_Failed)); | |
5603 | end if; | |
5604 | ||
84d0d4a5 | 5605 | Mark_Non_Null; |
5606 | return; | |
5607 | end if; | |
5608 | ||
5609 | -- If entity is never assigned, for sure a warning is appropriate | |
5610 | ||
5611 | if Is_Entity_Name (N) then | |
5612 | Check_Unset_Reference (N); | |
fa7497e8 | 5613 | end if; |
84d0d4a5 | 5614 | |
5615 | -- No check needed if checks are suppressed on the range. Note that we | |
5616 | -- don't set Is_Known_Non_Null in this case (we could legitimately do | |
5617 | -- so, since the program is erroneous, but we don't like to casually | |
5618 | -- propagate such conclusions from erroneosity). | |
5619 | ||
5620 | if Access_Checks_Suppressed (Typ) then | |
5621 | return; | |
5622 | end if; | |
5623 | ||
2af58f67 | 5624 | -- No check needed for access to concurrent record types generated by |
5625 | -- the expander. This is not just an optimization (though it does indeed | |
5626 | -- remove junk checks). It also avoids generation of junk warnings. | |
5627 | ||
5628 | if Nkind (N) in N_Has_Chars | |
5629 | and then Chars (N) = Name_uObject | |
5630 | and then Is_Concurrent_Record_Type | |
5631 | (Directly_Designated_Type (Etype (N))) | |
5632 | then | |
5633 | return; | |
5634 | end if; | |
5635 | ||
84d0d4a5 | 5636 | -- Otherwise install access check |
5637 | ||
5638 | Insert_Action (N, | |
5639 | Make_Raise_Constraint_Error (Loc, | |
5640 | Condition => | |
5641 | Make_Op_Eq (Loc, | |
5642 | Left_Opnd => Duplicate_Subexpr_Move_Checks (N), | |
5643 | Right_Opnd => Make_Null (Loc)), | |
5644 | Reason => CE_Access_Check_Failed)); | |
5645 | ||
5646 | Mark_Non_Null; | |
fa7497e8 | 5647 | end Install_Null_Excluding_Check; |
5648 | ||
ee6ba406 | 5649 | -------------------------- |
5650 | -- Install_Static_Check -- | |
5651 | -------------------------- | |
5652 | ||
5653 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is | |
5654 | Stat : constant Boolean := Is_Static_Expression (R_Cno); | |
5655 | Typ : constant Entity_Id := Etype (R_Cno); | |
5656 | ||
5657 | begin | |
f15731c4 | 5658 | Rewrite (R_Cno, |
5659 | Make_Raise_Constraint_Error (Loc, | |
5660 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 5661 | Set_Analyzed (R_Cno); |
5662 | Set_Etype (R_Cno, Typ); | |
5663 | Set_Raises_Constraint_Error (R_Cno); | |
5664 | Set_Is_Static_Expression (R_Cno, Stat); | |
840ab274 | 5665 | |
5666 | -- Now deal with possible local raise handling | |
5667 | ||
5668 | Possible_Local_Raise (R_Cno, Standard_Constraint_Error); | |
ee6ba406 | 5669 | end Install_Static_Check; |
5670 | ||
9dfe12ae | 5671 | --------------------- |
5672 | -- Kill_All_Checks -- | |
5673 | --------------------- | |
5674 | ||
5675 | procedure Kill_All_Checks is | |
5676 | begin | |
5677 | if Debug_Flag_CC then | |
5678 | w ("Kill_All_Checks"); | |
5679 | end if; | |
5680 | ||
feff2f05 | 5681 | -- We reset the number of saved checks to zero, and also modify all |
5682 | -- stack entries for statement ranges to indicate that the number of | |
5683 | -- checks at each level is now zero. | |
9dfe12ae | 5684 | |
5685 | Num_Saved_Checks := 0; | |
5686 | ||
96da3284 | 5687 | -- Note: the Int'Min here avoids any possibility of J being out of |
5688 | -- range when called from e.g. Conditional_Statements_Begin. | |
5689 | ||
5690 | for J in 1 .. Int'Min (Saved_Checks_TOS, Saved_Checks_Stack'Last) loop | |
9dfe12ae | 5691 | Saved_Checks_Stack (J) := 0; |
5692 | end loop; | |
5693 | end Kill_All_Checks; | |
5694 | ||
5695 | ----------------- | |
5696 | -- Kill_Checks -- | |
5697 | ----------------- | |
5698 | ||
5699 | procedure Kill_Checks (V : Entity_Id) is | |
5700 | begin | |
5701 | if Debug_Flag_CC then | |
5702 | w ("Kill_Checks for entity", Int (V)); | |
5703 | end if; | |
5704 | ||
5705 | for J in 1 .. Num_Saved_Checks loop | |
5706 | if Saved_Checks (J).Entity = V then | |
5707 | if Debug_Flag_CC then | |
5708 | w (" Checks killed for saved check ", J); | |
5709 | end if; | |
5710 | ||
5711 | Saved_Checks (J).Killed := True; | |
5712 | end if; | |
5713 | end loop; | |
5714 | end Kill_Checks; | |
5715 | ||
ee6ba406 | 5716 | ------------------------------ |
5717 | -- Length_Checks_Suppressed -- | |
5718 | ------------------------------ | |
5719 | ||
5720 | function Length_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5721 | begin | |
9dfe12ae | 5722 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
5723 | return Is_Check_Suppressed (E, Length_Check); | |
5724 | else | |
5725 | return Scope_Suppress (Length_Check); | |
5726 | end if; | |
ee6ba406 | 5727 | end Length_Checks_Suppressed; |
5728 | ||
5729 | -------------------------------- | |
5730 | -- Overflow_Checks_Suppressed -- | |
5731 | -------------------------------- | |
5732 | ||
5733 | function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5734 | begin | |
9dfe12ae | 5735 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
5736 | return Is_Check_Suppressed (E, Overflow_Check); | |
5737 | else | |
5738 | return Scope_Suppress (Overflow_Check); | |
5739 | end if; | |
ee6ba406 | 5740 | end Overflow_Checks_Suppressed; |
fc75802a | 5741 | |
ee6ba406 | 5742 | ----------------------------- |
5743 | -- Range_Checks_Suppressed -- | |
5744 | ----------------------------- | |
5745 | ||
5746 | function Range_Checks_Suppressed (E : Entity_Id) return Boolean is | |
5747 | begin | |
9dfe12ae | 5748 | if Present (E) then |
5749 | ||
5750 | -- Note: for now we always suppress range checks on Vax float types, | |
5751 | -- since Gigi does not know how to generate these checks. | |
5752 | ||
5753 | if Vax_Float (E) then | |
5754 | return True; | |
5755 | elsif Kill_Range_Checks (E) then | |
5756 | return True; | |
5757 | elsif Checks_May_Be_Suppressed (E) then | |
5758 | return Is_Check_Suppressed (E, Range_Check); | |
5759 | end if; | |
5760 | end if; | |
ee6ba406 | 5761 | |
9dfe12ae | 5762 | return Scope_Suppress (Range_Check); |
ee6ba406 | 5763 | end Range_Checks_Suppressed; |
5764 | ||
0577b0b1 | 5765 | ----------------------------------------- |
5766 | -- Range_Or_Validity_Checks_Suppressed -- | |
5767 | ----------------------------------------- | |
5768 | ||
5769 | -- Note: the coding would be simpler here if we simply made appropriate | |
5770 | -- calls to Range/Validity_Checks_Suppressed, but that would result in | |
5771 | -- duplicated checks which we prefer to avoid. | |
5772 | ||
5773 | function Range_Or_Validity_Checks_Suppressed | |
5774 | (Expr : Node_Id) return Boolean | |
5775 | is | |
5776 | begin | |
5777 | -- Immediate return if scope checks suppressed for either check | |
5778 | ||
5779 | if Scope_Suppress (Range_Check) or Scope_Suppress (Validity_Check) then | |
5780 | return True; | |
5781 | end if; | |
5782 | ||
5783 | -- If no expression, that's odd, decide that checks are suppressed, | |
5784 | -- since we don't want anyone trying to do checks in this case, which | |
5785 | -- is most likely the result of some other error. | |
5786 | ||
5787 | if No (Expr) then | |
5788 | return True; | |
5789 | end if; | |
5790 | ||
5791 | -- Expression is present, so perform suppress checks on type | |
5792 | ||
5793 | declare | |
5794 | Typ : constant Entity_Id := Etype (Expr); | |
5795 | begin | |
5796 | if Vax_Float (Typ) then | |
5797 | return True; | |
5798 | elsif Checks_May_Be_Suppressed (Typ) | |
5799 | and then (Is_Check_Suppressed (Typ, Range_Check) | |
5800 | or else | |
5801 | Is_Check_Suppressed (Typ, Validity_Check)) | |
5802 | then | |
5803 | return True; | |
5804 | end if; | |
5805 | end; | |
5806 | ||
5807 | -- If expression is an entity name, perform checks on this entity | |
5808 | ||
5809 | if Is_Entity_Name (Expr) then | |
5810 | declare | |
5811 | Ent : constant Entity_Id := Entity (Expr); | |
5812 | begin | |
5813 | if Checks_May_Be_Suppressed (Ent) then | |
5814 | return Is_Check_Suppressed (Ent, Range_Check) | |
5815 | or else Is_Check_Suppressed (Ent, Validity_Check); | |
5816 | end if; | |
5817 | end; | |
5818 | end if; | |
5819 | ||
5820 | -- If we fall through, no checks suppressed | |
5821 | ||
5822 | return False; | |
5823 | end Range_Or_Validity_Checks_Suppressed; | |
5824 | ||
226494a3 | 5825 | ------------------- |
5826 | -- Remove_Checks -- | |
5827 | ------------------- | |
5828 | ||
5829 | procedure Remove_Checks (Expr : Node_Id) is | |
226494a3 | 5830 | function Process (N : Node_Id) return Traverse_Result; |
5831 | -- Process a single node during the traversal | |
5832 | ||
8f6e4fd5 | 5833 | procedure Traverse is new Traverse_Proc (Process); |
5834 | -- The traversal procedure itself | |
226494a3 | 5835 | |
5836 | ------------- | |
5837 | -- Process -- | |
5838 | ------------- | |
5839 | ||
5840 | function Process (N : Node_Id) return Traverse_Result is | |
5841 | begin | |
5842 | if Nkind (N) not in N_Subexpr then | |
5843 | return Skip; | |
5844 | end if; | |
5845 | ||
5846 | Set_Do_Range_Check (N, False); | |
5847 | ||
5848 | case Nkind (N) is | |
5849 | when N_And_Then => | |
8f6e4fd5 | 5850 | Traverse (Left_Opnd (N)); |
226494a3 | 5851 | return Skip; |
5852 | ||
5853 | when N_Attribute_Reference => | |
226494a3 | 5854 | Set_Do_Overflow_Check (N, False); |
5855 | ||
226494a3 | 5856 | when N_Function_Call => |
5857 | Set_Do_Tag_Check (N, False); | |
5858 | ||
226494a3 | 5859 | when N_Op => |
5860 | Set_Do_Overflow_Check (N, False); | |
5861 | ||
5862 | case Nkind (N) is | |
5863 | when N_Op_Divide => | |
5864 | Set_Do_Division_Check (N, False); | |
5865 | ||
5866 | when N_Op_And => | |
5867 | Set_Do_Length_Check (N, False); | |
5868 | ||
5869 | when N_Op_Mod => | |
5870 | Set_Do_Division_Check (N, False); | |
5871 | ||
5872 | when N_Op_Or => | |
5873 | Set_Do_Length_Check (N, False); | |
5874 | ||
5875 | when N_Op_Rem => | |
5876 | Set_Do_Division_Check (N, False); | |
5877 | ||
5878 | when N_Op_Xor => | |
5879 | Set_Do_Length_Check (N, False); | |
5880 | ||
5881 | when others => | |
5882 | null; | |
5883 | end case; | |
5884 | ||
5885 | when N_Or_Else => | |
8f6e4fd5 | 5886 | Traverse (Left_Opnd (N)); |
226494a3 | 5887 | return Skip; |
5888 | ||
5889 | when N_Selected_Component => | |
226494a3 | 5890 | Set_Do_Discriminant_Check (N, False); |
5891 | ||
226494a3 | 5892 | when N_Type_Conversion => |
9dfe12ae | 5893 | Set_Do_Length_Check (N, False); |
5894 | Set_Do_Tag_Check (N, False); | |
226494a3 | 5895 | Set_Do_Overflow_Check (N, False); |
226494a3 | 5896 | |
5897 | when others => | |
5898 | null; | |
5899 | end case; | |
5900 | ||
5901 | return OK; | |
5902 | end Process; | |
5903 | ||
5904 | -- Start of processing for Remove_Checks | |
5905 | ||
5906 | begin | |
8f6e4fd5 | 5907 | Traverse (Expr); |
226494a3 | 5908 | end Remove_Checks; |
5909 | ||
ee6ba406 | 5910 | ---------------------------- |
5911 | -- Selected_Length_Checks -- | |
5912 | ---------------------------- | |
5913 | ||
5914 | function Selected_Length_Checks | |
5915 | (Ck_Node : Node_Id; | |
5916 | Target_Typ : Entity_Id; | |
5917 | Source_Typ : Entity_Id; | |
314a23b6 | 5918 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 5919 | is |
5920 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
5921 | S_Typ : Entity_Id; | |
5922 | T_Typ : Entity_Id; | |
5923 | Expr_Actual : Node_Id; | |
5924 | Exptyp : Entity_Id; | |
5925 | Cond : Node_Id := Empty; | |
5926 | Do_Access : Boolean := False; | |
5927 | Wnode : Node_Id := Warn_Node; | |
5928 | Ret_Result : Check_Result := (Empty, Empty); | |
5929 | Num_Checks : Natural := 0; | |
5930 | ||
5931 | procedure Add_Check (N : Node_Id); | |
5932 | -- Adds the action given to Ret_Result if N is non-Empty | |
5933 | ||
5934 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id; | |
5935 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id; | |
314a23b6 | 5936 | -- Comments required ??? |
ee6ba406 | 5937 | |
5938 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean; | |
5939 | -- True for equal literals and for nodes that denote the same constant | |
5f260d20 | 5940 | -- entity, even if its value is not a static constant. This includes the |
9dfe12ae | 5941 | -- case of a discriminal reference within an init proc. Removes some |
5f260d20 | 5942 | -- obviously superfluous checks. |
ee6ba406 | 5943 | |
5944 | function Length_E_Cond | |
5945 | (Exptyp : Entity_Id; | |
5946 | Typ : Entity_Id; | |
314a23b6 | 5947 | Indx : Nat) return Node_Id; |
ee6ba406 | 5948 | -- Returns expression to compute: |
5949 | -- Typ'Length /= Exptyp'Length | |
5950 | ||
5951 | function Length_N_Cond | |
5952 | (Expr : Node_Id; | |
5953 | Typ : Entity_Id; | |
314a23b6 | 5954 | Indx : Nat) return Node_Id; |
ee6ba406 | 5955 | -- Returns expression to compute: |
5956 | -- Typ'Length /= Expr'Length | |
5957 | ||
5958 | --------------- | |
5959 | -- Add_Check -- | |
5960 | --------------- | |
5961 | ||
5962 | procedure Add_Check (N : Node_Id) is | |
5963 | begin | |
5964 | if Present (N) then | |
5965 | ||
5966 | -- For now, ignore attempt to place more than 2 checks ??? | |
5967 | ||
5968 | if Num_Checks = 2 then | |
5969 | return; | |
5970 | end if; | |
5971 | ||
5972 | pragma Assert (Num_Checks <= 1); | |
5973 | Num_Checks := Num_Checks + 1; | |
5974 | Ret_Result (Num_Checks) := N; | |
5975 | end if; | |
5976 | end Add_Check; | |
5977 | ||
5978 | ------------------ | |
5979 | -- Get_E_Length -- | |
5980 | ------------------ | |
5981 | ||
5982 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is | |
00c403ee | 5983 | SE : constant Entity_Id := Scope (E); |
ee6ba406 | 5984 | N : Node_Id; |
5985 | E1 : Entity_Id := E; | |
ee6ba406 | 5986 | |
5987 | begin | |
5988 | if Ekind (Scope (E)) = E_Record_Type | |
5989 | and then Has_Discriminants (Scope (E)) | |
5990 | then | |
5991 | N := Build_Discriminal_Subtype_Of_Component (E); | |
5992 | ||
5993 | if Present (N) then | |
5994 | Insert_Action (Ck_Node, N); | |
5995 | E1 := Defining_Identifier (N); | |
5996 | end if; | |
5997 | end if; | |
5998 | ||
5999 | if Ekind (E1) = E_String_Literal_Subtype then | |
6000 | return | |
6001 | Make_Integer_Literal (Loc, | |
6002 | Intval => String_Literal_Length (E1)); | |
6003 | ||
00c403ee | 6004 | elsif SE /= Standard_Standard |
6005 | and then Ekind (Scope (SE)) = E_Protected_Type | |
6006 | and then Has_Discriminants (Scope (SE)) | |
6007 | and then Has_Completion (Scope (SE)) | |
ee6ba406 | 6008 | and then not Inside_Init_Proc |
6009 | then | |
ee6ba406 | 6010 | -- If the type whose length is needed is a private component |
6011 | -- constrained by a discriminant, we must expand the 'Length | |
6012 | -- attribute into an explicit computation, using the discriminal | |
6013 | -- of the current protected operation. This is because the actual | |
6014 | -- type of the prival is constructed after the protected opera- | |
6015 | -- tion has been fully expanded. | |
6016 | ||
6017 | declare | |
6018 | Indx_Type : Node_Id; | |
6019 | Lo : Node_Id; | |
6020 | Hi : Node_Id; | |
6021 | Do_Expand : Boolean := False; | |
6022 | ||
6023 | begin | |
6024 | Indx_Type := First_Index (E); | |
6025 | ||
6026 | for J in 1 .. Indx - 1 loop | |
6027 | Next_Index (Indx_Type); | |
6028 | end loop; | |
6029 | ||
2af58f67 | 6030 | Get_Index_Bounds (Indx_Type, Lo, Hi); |
ee6ba406 | 6031 | |
6032 | if Nkind (Lo) = N_Identifier | |
6033 | and then Ekind (Entity (Lo)) = E_In_Parameter | |
6034 | then | |
6035 | Lo := Get_Discriminal (E, Lo); | |
6036 | Do_Expand := True; | |
6037 | end if; | |
6038 | ||
6039 | if Nkind (Hi) = N_Identifier | |
6040 | and then Ekind (Entity (Hi)) = E_In_Parameter | |
6041 | then | |
6042 | Hi := Get_Discriminal (E, Hi); | |
6043 | Do_Expand := True; | |
6044 | end if; | |
6045 | ||
6046 | if Do_Expand then | |
6047 | if not Is_Entity_Name (Lo) then | |
9dfe12ae | 6048 | Lo := Duplicate_Subexpr_No_Checks (Lo); |
ee6ba406 | 6049 | end if; |
6050 | ||
6051 | if not Is_Entity_Name (Hi) then | |
9dfe12ae | 6052 | Lo := Duplicate_Subexpr_No_Checks (Hi); |
ee6ba406 | 6053 | end if; |
6054 | ||
6055 | N := | |
6056 | Make_Op_Add (Loc, | |
6057 | Left_Opnd => | |
6058 | Make_Op_Subtract (Loc, | |
6059 | Left_Opnd => Hi, | |
6060 | Right_Opnd => Lo), | |
6061 | ||
6062 | Right_Opnd => Make_Integer_Literal (Loc, 1)); | |
6063 | return N; | |
6064 | ||
6065 | else | |
6066 | N := | |
6067 | Make_Attribute_Reference (Loc, | |
6068 | Attribute_Name => Name_Length, | |
6069 | Prefix => | |
6070 | New_Occurrence_Of (E1, Loc)); | |
6071 | ||
6072 | if Indx > 1 then | |
6073 | Set_Expressions (N, New_List ( | |
6074 | Make_Integer_Literal (Loc, Indx))); | |
6075 | end if; | |
6076 | ||
6077 | return N; | |
6078 | end if; | |
6079 | end; | |
6080 | ||
6081 | else | |
6082 | N := | |
6083 | Make_Attribute_Reference (Loc, | |
6084 | Attribute_Name => Name_Length, | |
6085 | Prefix => | |
6086 | New_Occurrence_Of (E1, Loc)); | |
6087 | ||
6088 | if Indx > 1 then | |
6089 | Set_Expressions (N, New_List ( | |
6090 | Make_Integer_Literal (Loc, Indx))); | |
6091 | end if; | |
6092 | ||
6093 | return N; | |
ee6ba406 | 6094 | end if; |
6095 | end Get_E_Length; | |
6096 | ||
6097 | ------------------ | |
6098 | -- Get_N_Length -- | |
6099 | ------------------ | |
6100 | ||
6101 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is | |
6102 | begin | |
6103 | return | |
6104 | Make_Attribute_Reference (Loc, | |
6105 | Attribute_Name => Name_Length, | |
6106 | Prefix => | |
9dfe12ae | 6107 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 6108 | Expressions => New_List ( |
6109 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 6110 | end Get_N_Length; |
6111 | ||
6112 | ------------------- | |
6113 | -- Length_E_Cond -- | |
6114 | ------------------- | |
6115 | ||
6116 | function Length_E_Cond | |
6117 | (Exptyp : Entity_Id; | |
6118 | Typ : Entity_Id; | |
314a23b6 | 6119 | Indx : Nat) return Node_Id |
ee6ba406 | 6120 | is |
6121 | begin | |
6122 | return | |
6123 | Make_Op_Ne (Loc, | |
6124 | Left_Opnd => Get_E_Length (Typ, Indx), | |
6125 | Right_Opnd => Get_E_Length (Exptyp, Indx)); | |
ee6ba406 | 6126 | end Length_E_Cond; |
6127 | ||
6128 | ------------------- | |
6129 | -- Length_N_Cond -- | |
6130 | ------------------- | |
6131 | ||
6132 | function Length_N_Cond | |
6133 | (Expr : Node_Id; | |
6134 | Typ : Entity_Id; | |
314a23b6 | 6135 | Indx : Nat) return Node_Id |
ee6ba406 | 6136 | is |
6137 | begin | |
6138 | return | |
6139 | Make_Op_Ne (Loc, | |
6140 | Left_Opnd => Get_E_Length (Typ, Indx), | |
6141 | Right_Opnd => Get_N_Length (Expr, Indx)); | |
ee6ba406 | 6142 | end Length_N_Cond; |
6143 | ||
feff2f05 | 6144 | ----------------- |
6145 | -- Same_Bounds -- | |
6146 | ----------------- | |
6147 | ||
ee6ba406 | 6148 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is |
6149 | begin | |
6150 | return | |
6151 | (Nkind (L) = N_Integer_Literal | |
6152 | and then Nkind (R) = N_Integer_Literal | |
6153 | and then Intval (L) = Intval (R)) | |
6154 | ||
6155 | or else | |
6156 | (Is_Entity_Name (L) | |
6157 | and then Ekind (Entity (L)) = E_Constant | |
6158 | and then ((Is_Entity_Name (R) | |
6159 | and then Entity (L) = Entity (R)) | |
6160 | or else | |
6161 | (Nkind (R) = N_Type_Conversion | |
6162 | and then Is_Entity_Name (Expression (R)) | |
6163 | and then Entity (L) = Entity (Expression (R))))) | |
6164 | ||
6165 | or else | |
6166 | (Is_Entity_Name (R) | |
6167 | and then Ekind (Entity (R)) = E_Constant | |
6168 | and then Nkind (L) = N_Type_Conversion | |
6169 | and then Is_Entity_Name (Expression (L)) | |
5f260d20 | 6170 | and then Entity (R) = Entity (Expression (L))) |
6171 | ||
6172 | or else | |
6173 | (Is_Entity_Name (L) | |
6174 | and then Is_Entity_Name (R) | |
6175 | and then Entity (L) = Entity (R) | |
6176 | and then Ekind (Entity (L)) = E_In_Parameter | |
6177 | and then Inside_Init_Proc); | |
ee6ba406 | 6178 | end Same_Bounds; |
6179 | ||
6180 | -- Start of processing for Selected_Length_Checks | |
6181 | ||
6182 | begin | |
6183 | if not Expander_Active then | |
6184 | return Ret_Result; | |
6185 | end if; | |
6186 | ||
6187 | if Target_Typ = Any_Type | |
6188 | or else Target_Typ = Any_Composite | |
6189 | or else Raises_Constraint_Error (Ck_Node) | |
6190 | then | |
6191 | return Ret_Result; | |
6192 | end if; | |
6193 | ||
6194 | if No (Wnode) then | |
6195 | Wnode := Ck_Node; | |
6196 | end if; | |
6197 | ||
6198 | T_Typ := Target_Typ; | |
6199 | ||
6200 | if No (Source_Typ) then | |
6201 | S_Typ := Etype (Ck_Node); | |
6202 | else | |
6203 | S_Typ := Source_Typ; | |
6204 | end if; | |
6205 | ||
6206 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
6207 | return Ret_Result; | |
6208 | end if; | |
6209 | ||
6210 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
6211 | S_Typ := Designated_Type (S_Typ); | |
6212 | T_Typ := Designated_Type (T_Typ); | |
6213 | Do_Access := True; | |
6214 | ||
2af58f67 | 6215 | -- A simple optimization for the null case |
ee6ba406 | 6216 | |
2af58f67 | 6217 | if Known_Null (Ck_Node) then |
ee6ba406 | 6218 | return Ret_Result; |
6219 | end if; | |
6220 | end if; | |
6221 | ||
6222 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
6223 | if Is_Constrained (T_Typ) then | |
6224 | ||
6225 | -- The checking code to be generated will freeze the | |
6226 | -- corresponding array type. However, we must freeze the | |
6227 | -- type now, so that the freeze node does not appear within | |
6fb3c314 | 6228 | -- the generated conditional expression, but ahead of it. |
ee6ba406 | 6229 | |
6230 | Freeze_Before (Ck_Node, T_Typ); | |
6231 | ||
6232 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
84d0d4a5 | 6233 | Exptyp := Get_Actual_Subtype (Ck_Node); |
ee6ba406 | 6234 | |
6235 | if Is_Access_Type (Exptyp) then | |
6236 | Exptyp := Designated_Type (Exptyp); | |
6237 | end if; | |
6238 | ||
6239 | -- String_Literal case. This needs to be handled specially be- | |
6240 | -- cause no index types are available for string literals. The | |
6241 | -- condition is simply: | |
6242 | ||
6243 | -- T_Typ'Length = string-literal-length | |
6244 | ||
9dfe12ae | 6245 | if Nkind (Expr_Actual) = N_String_Literal |
6246 | and then Ekind (Etype (Expr_Actual)) = E_String_Literal_Subtype | |
6247 | then | |
ee6ba406 | 6248 | Cond := |
6249 | Make_Op_Ne (Loc, | |
6250 | Left_Opnd => Get_E_Length (T_Typ, 1), | |
6251 | Right_Opnd => | |
6252 | Make_Integer_Literal (Loc, | |
6253 | Intval => | |
6254 | String_Literal_Length (Etype (Expr_Actual)))); | |
6255 | ||
6256 | -- General array case. Here we have a usable actual subtype for | |
6257 | -- the expression, and the condition is built from the two types | |
6258 | -- (Do_Length): | |
6259 | ||
6260 | -- T_Typ'Length /= Exptyp'Length or else | |
6261 | -- T_Typ'Length (2) /= Exptyp'Length (2) or else | |
6262 | -- T_Typ'Length (3) /= Exptyp'Length (3) or else | |
6263 | -- ... | |
6264 | ||
6265 | elsif Is_Constrained (Exptyp) then | |
6266 | declare | |
9dfe12ae | 6267 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
6268 | ||
6269 | L_Index : Node_Id; | |
6270 | R_Index : Node_Id; | |
6271 | L_Low : Node_Id; | |
6272 | L_High : Node_Id; | |
6273 | R_Low : Node_Id; | |
6274 | R_High : Node_Id; | |
ee6ba406 | 6275 | L_Length : Uint; |
6276 | R_Length : Uint; | |
9dfe12ae | 6277 | Ref_Node : Node_Id; |
ee6ba406 | 6278 | |
6279 | begin | |
feff2f05 | 6280 | -- At the library level, we need to ensure that the type of |
6281 | -- the object is elaborated before the check itself is | |
6282 | -- emitted. This is only done if the object is in the | |
6283 | -- current compilation unit, otherwise the type is frozen | |
6284 | -- and elaborated in its unit. | |
9dfe12ae | 6285 | |
6286 | if Is_Itype (Exptyp) | |
6287 | and then | |
6288 | Ekind (Cunit_Entity (Current_Sem_Unit)) = E_Package | |
6289 | and then | |
6290 | not In_Package_Body (Cunit_Entity (Current_Sem_Unit)) | |
d66aa9f6 | 6291 | and then In_Open_Scopes (Scope (Exptyp)) |
9dfe12ae | 6292 | then |
6293 | Ref_Node := Make_Itype_Reference (Sloc (Ck_Node)); | |
6294 | Set_Itype (Ref_Node, Exptyp); | |
6295 | Insert_Action (Ck_Node, Ref_Node); | |
6296 | end if; | |
6297 | ||
ee6ba406 | 6298 | L_Index := First_Index (T_Typ); |
6299 | R_Index := First_Index (Exptyp); | |
6300 | ||
6301 | for Indx in 1 .. Ndims loop | |
6302 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 6303 | or else |
6304 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 6305 | then |
6306 | Get_Index_Bounds (L_Index, L_Low, L_High); | |
6307 | Get_Index_Bounds (R_Index, R_Low, R_High); | |
6308 | ||
6309 | -- Deal with compile time length check. Note that we | |
6310 | -- skip this in the access case, because the access | |
6311 | -- value may be null, so we cannot know statically. | |
6312 | ||
6313 | if not Do_Access | |
6314 | and then Compile_Time_Known_Value (L_Low) | |
6315 | and then Compile_Time_Known_Value (L_High) | |
6316 | and then Compile_Time_Known_Value (R_Low) | |
6317 | and then Compile_Time_Known_Value (R_High) | |
6318 | then | |
6319 | if Expr_Value (L_High) >= Expr_Value (L_Low) then | |
6320 | L_Length := Expr_Value (L_High) - | |
6321 | Expr_Value (L_Low) + 1; | |
6322 | else | |
6323 | L_Length := UI_From_Int (0); | |
6324 | end if; | |
6325 | ||
6326 | if Expr_Value (R_High) >= Expr_Value (R_Low) then | |
6327 | R_Length := Expr_Value (R_High) - | |
6328 | Expr_Value (R_Low) + 1; | |
6329 | else | |
6330 | R_Length := UI_From_Int (0); | |
6331 | end if; | |
6332 | ||
6333 | if L_Length > R_Length then | |
6334 | Add_Check | |
6335 | (Compile_Time_Constraint_Error | |
6336 | (Wnode, "too few elements for}?", T_Typ)); | |
6337 | ||
6338 | elsif L_Length < R_Length then | |
6339 | Add_Check | |
6340 | (Compile_Time_Constraint_Error | |
6341 | (Wnode, "too many elements for}?", T_Typ)); | |
6342 | end if; | |
6343 | ||
6344 | -- The comparison for an individual index subtype | |
6345 | -- is omitted if the corresponding index subtypes | |
6346 | -- statically match, since the result is known to | |
6347 | -- be true. Note that this test is worth while even | |
6348 | -- though we do static evaluation, because non-static | |
6349 | -- subtypes can statically match. | |
6350 | ||
6351 | elsif not | |
6352 | Subtypes_Statically_Match | |
6353 | (Etype (L_Index), Etype (R_Index)) | |
6354 | ||
6355 | and then not | |
6356 | (Same_Bounds (L_Low, R_Low) | |
6357 | and then Same_Bounds (L_High, R_High)) | |
6358 | then | |
6359 | Evolve_Or_Else | |
6360 | (Cond, Length_E_Cond (Exptyp, T_Typ, Indx)); | |
6361 | end if; | |
6362 | ||
6363 | Next (L_Index); | |
6364 | Next (R_Index); | |
6365 | end if; | |
6366 | end loop; | |
6367 | end; | |
6368 | ||
6369 | -- Handle cases where we do not get a usable actual subtype that | |
6370 | -- is constrained. This happens for example in the function call | |
6371 | -- and explicit dereference cases. In these cases, we have to get | |
6372 | -- the length or range from the expression itself, making sure we | |
6373 | -- do not evaluate it more than once. | |
6374 | ||
6375 | -- Here Ck_Node is the original expression, or more properly the | |
feff2f05 | 6376 | -- result of applying Duplicate_Expr to the original tree, forcing |
6377 | -- the result to be a name. | |
ee6ba406 | 6378 | |
6379 | else | |
6380 | declare | |
9dfe12ae | 6381 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 6382 | |
6383 | begin | |
6384 | -- Build the condition for the explicit dereference case | |
6385 | ||
6386 | for Indx in 1 .. Ndims loop | |
6387 | Evolve_Or_Else | |
6388 | (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx)); | |
6389 | end loop; | |
6390 | end; | |
6391 | end if; | |
6392 | end if; | |
6393 | end if; | |
6394 | ||
6395 | -- Construct the test and insert into the tree | |
6396 | ||
6397 | if Present (Cond) then | |
6398 | if Do_Access then | |
6399 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
6400 | end if; | |
6401 | ||
f15731c4 | 6402 | Add_Check |
6403 | (Make_Raise_Constraint_Error (Loc, | |
6404 | Condition => Cond, | |
6405 | Reason => CE_Length_Check_Failed)); | |
ee6ba406 | 6406 | end if; |
6407 | ||
6408 | return Ret_Result; | |
ee6ba406 | 6409 | end Selected_Length_Checks; |
6410 | ||
6411 | --------------------------- | |
6412 | -- Selected_Range_Checks -- | |
6413 | --------------------------- | |
6414 | ||
6415 | function Selected_Range_Checks | |
6416 | (Ck_Node : Node_Id; | |
6417 | Target_Typ : Entity_Id; | |
6418 | Source_Typ : Entity_Id; | |
314a23b6 | 6419 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 6420 | is |
6421 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
6422 | S_Typ : Entity_Id; | |
6423 | T_Typ : Entity_Id; | |
6424 | Expr_Actual : Node_Id; | |
6425 | Exptyp : Entity_Id; | |
6426 | Cond : Node_Id := Empty; | |
6427 | Do_Access : Boolean := False; | |
6428 | Wnode : Node_Id := Warn_Node; | |
6429 | Ret_Result : Check_Result := (Empty, Empty); | |
6430 | Num_Checks : Integer := 0; | |
6431 | ||
6432 | procedure Add_Check (N : Node_Id); | |
6433 | -- Adds the action given to Ret_Result if N is non-Empty | |
6434 | ||
6435 | function Discrete_Range_Cond | |
6436 | (Expr : Node_Id; | |
314a23b6 | 6437 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 6438 | -- Returns expression to compute: |
6439 | -- Low_Bound (Expr) < Typ'First | |
6440 | -- or else | |
6441 | -- High_Bound (Expr) > Typ'Last | |
6442 | ||
6443 | function Discrete_Expr_Cond | |
6444 | (Expr : Node_Id; | |
314a23b6 | 6445 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 6446 | -- Returns expression to compute: |
6447 | -- Expr < Typ'First | |
6448 | -- or else | |
6449 | -- Expr > Typ'Last | |
6450 | ||
6451 | function Get_E_First_Or_Last | |
3cb12758 | 6452 | (Loc : Source_Ptr; |
6453 | E : Entity_Id; | |
ee6ba406 | 6454 | Indx : Nat; |
314a23b6 | 6455 | Nam : Name_Id) return Node_Id; |
79212397 | 6456 | -- Returns an attribute reference |
ee6ba406 | 6457 | -- E'First or E'Last |
79212397 | 6458 | -- with a source location of Loc. |
f73ee678 | 6459 | -- |
79212397 | 6460 | -- Nam is Name_First or Name_Last, according to which attribute is |
6461 | -- desired. If Indx is non-zero, it is passed as a literal in the | |
6462 | -- Expressions of the attribute reference (identifying the desired | |
6463 | -- array dimension). | |
ee6ba406 | 6464 | |
6465 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id; | |
6466 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id; | |
6467 | -- Returns expression to compute: | |
9dfe12ae | 6468 | -- N'First or N'Last using Duplicate_Subexpr_No_Checks |
ee6ba406 | 6469 | |
6470 | function Range_E_Cond | |
6471 | (Exptyp : Entity_Id; | |
6472 | Typ : Entity_Id; | |
6473 | Indx : Nat) | |
6474 | return Node_Id; | |
6475 | -- Returns expression to compute: | |
6476 | -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last | |
6477 | ||
6478 | function Range_Equal_E_Cond | |
6479 | (Exptyp : Entity_Id; | |
6480 | Typ : Entity_Id; | |
314a23b6 | 6481 | Indx : Nat) return Node_Id; |
ee6ba406 | 6482 | -- Returns expression to compute: |
6483 | -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last | |
6484 | ||
6485 | function Range_N_Cond | |
6486 | (Expr : Node_Id; | |
6487 | Typ : Entity_Id; | |
314a23b6 | 6488 | Indx : Nat) return Node_Id; |
ee6ba406 | 6489 | -- Return expression to compute: |
6490 | -- Expr'First < Typ'First or else Expr'Last > Typ'Last | |
6491 | ||
6492 | --------------- | |
6493 | -- Add_Check -- | |
6494 | --------------- | |
6495 | ||
6496 | procedure Add_Check (N : Node_Id) is | |
6497 | begin | |
6498 | if Present (N) then | |
6499 | ||
6500 | -- For now, ignore attempt to place more than 2 checks ??? | |
6501 | ||
6502 | if Num_Checks = 2 then | |
6503 | return; | |
6504 | end if; | |
6505 | ||
6506 | pragma Assert (Num_Checks <= 1); | |
6507 | Num_Checks := Num_Checks + 1; | |
6508 | Ret_Result (Num_Checks) := N; | |
6509 | end if; | |
6510 | end Add_Check; | |
6511 | ||
6512 | ------------------------- | |
6513 | -- Discrete_Expr_Cond -- | |
6514 | ------------------------- | |
6515 | ||
6516 | function Discrete_Expr_Cond | |
6517 | (Expr : Node_Id; | |
314a23b6 | 6518 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 6519 | is |
6520 | begin | |
6521 | return | |
6522 | Make_Or_Else (Loc, | |
6523 | Left_Opnd => | |
6524 | Make_Op_Lt (Loc, | |
6525 | Left_Opnd => | |
9dfe12ae | 6526 | Convert_To (Base_Type (Typ), |
6527 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 6528 | Right_Opnd => |
6529 | Convert_To (Base_Type (Typ), | |
3cb12758 | 6530 | Get_E_First_Or_Last (Loc, Typ, 0, Name_First))), |
ee6ba406 | 6531 | |
6532 | Right_Opnd => | |
6533 | Make_Op_Gt (Loc, | |
6534 | Left_Opnd => | |
9dfe12ae | 6535 | Convert_To (Base_Type (Typ), |
6536 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 6537 | Right_Opnd => |
6538 | Convert_To | |
6539 | (Base_Type (Typ), | |
3cb12758 | 6540 | Get_E_First_Or_Last (Loc, Typ, 0, Name_Last)))); |
ee6ba406 | 6541 | end Discrete_Expr_Cond; |
6542 | ||
6543 | ------------------------- | |
6544 | -- Discrete_Range_Cond -- | |
6545 | ------------------------- | |
6546 | ||
6547 | function Discrete_Range_Cond | |
6548 | (Expr : Node_Id; | |
314a23b6 | 6549 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 6550 | is |
6551 | LB : Node_Id := Low_Bound (Expr); | |
6552 | HB : Node_Id := High_Bound (Expr); | |
6553 | ||
6554 | Left_Opnd : Node_Id; | |
6555 | Right_Opnd : Node_Id; | |
6556 | ||
6557 | begin | |
6558 | if Nkind (LB) = N_Identifier | |
feff2f05 | 6559 | and then Ekind (Entity (LB)) = E_Discriminant |
6560 | then | |
ee6ba406 | 6561 | LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc); |
6562 | end if; | |
6563 | ||
6564 | if Nkind (HB) = N_Identifier | |
feff2f05 | 6565 | and then Ekind (Entity (HB)) = E_Discriminant |
6566 | then | |
ee6ba406 | 6567 | HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc); |
6568 | end if; | |
6569 | ||
6570 | Left_Opnd := | |
6571 | Make_Op_Lt (Loc, | |
6572 | Left_Opnd => | |
6573 | Convert_To | |
9dfe12ae | 6574 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (LB)), |
ee6ba406 | 6575 | |
6576 | Right_Opnd => | |
6577 | Convert_To | |
3cb12758 | 6578 | (Base_Type (Typ), |
6579 | Get_E_First_Or_Last (Loc, Typ, 0, Name_First))); | |
ee6ba406 | 6580 | |
6581 | if Base_Type (Typ) = Typ then | |
6582 | return Left_Opnd; | |
6583 | ||
6584 | elsif Compile_Time_Known_Value (High_Bound (Scalar_Range (Typ))) | |
6585 | and then | |
6586 | Compile_Time_Known_Value (High_Bound (Scalar_Range | |
6587 | (Base_Type (Typ)))) | |
6588 | then | |
6589 | if Is_Floating_Point_Type (Typ) then | |
6590 | if Expr_Value_R (High_Bound (Scalar_Range (Typ))) = | |
6591 | Expr_Value_R (High_Bound (Scalar_Range (Base_Type (Typ)))) | |
6592 | then | |
6593 | return Left_Opnd; | |
6594 | end if; | |
6595 | ||
6596 | else | |
6597 | if Expr_Value (High_Bound (Scalar_Range (Typ))) = | |
6598 | Expr_Value (High_Bound (Scalar_Range (Base_Type (Typ)))) | |
6599 | then | |
6600 | return Left_Opnd; | |
6601 | end if; | |
6602 | end if; | |
6603 | end if; | |
6604 | ||
6605 | Right_Opnd := | |
6606 | Make_Op_Gt (Loc, | |
6607 | Left_Opnd => | |
6608 | Convert_To | |
9dfe12ae | 6609 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (HB)), |
ee6ba406 | 6610 | |
6611 | Right_Opnd => | |
6612 | Convert_To | |
6613 | (Base_Type (Typ), | |
3cb12758 | 6614 | Get_E_First_Or_Last (Loc, Typ, 0, Name_Last))); |
ee6ba406 | 6615 | |
6616 | return Make_Or_Else (Loc, Left_Opnd, Right_Opnd); | |
6617 | end Discrete_Range_Cond; | |
6618 | ||
6619 | ------------------------- | |
6620 | -- Get_E_First_Or_Last -- | |
6621 | ------------------------- | |
6622 | ||
6623 | function Get_E_First_Or_Last | |
3cb12758 | 6624 | (Loc : Source_Ptr; |
6625 | E : Entity_Id; | |
ee6ba406 | 6626 | Indx : Nat; |
314a23b6 | 6627 | Nam : Name_Id) return Node_Id |
ee6ba406 | 6628 | is |
3cb12758 | 6629 | Exprs : List_Id; |
ee6ba406 | 6630 | begin |
3cb12758 | 6631 | if Indx > 0 then |
6632 | Exprs := New_List (Make_Integer_Literal (Loc, UI_From_Int (Indx))); | |
ee6ba406 | 6633 | else |
3cb12758 | 6634 | Exprs := No_List; |
ee6ba406 | 6635 | end if; |
6636 | ||
3cb12758 | 6637 | return Make_Attribute_Reference (Loc, |
6638 | Prefix => New_Occurrence_Of (E, Loc), | |
6639 | Attribute_Name => Nam, | |
6640 | Expressions => Exprs); | |
ee6ba406 | 6641 | end Get_E_First_Or_Last; |
6642 | ||
6643 | ----------------- | |
6644 | -- Get_N_First -- | |
6645 | ----------------- | |
6646 | ||
6647 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is | |
6648 | begin | |
6649 | return | |
6650 | Make_Attribute_Reference (Loc, | |
6651 | Attribute_Name => Name_First, | |
6652 | Prefix => | |
9dfe12ae | 6653 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 6654 | Expressions => New_List ( |
6655 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 6656 | end Get_N_First; |
6657 | ||
6658 | ---------------- | |
6659 | -- Get_N_Last -- | |
6660 | ---------------- | |
6661 | ||
6662 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is | |
6663 | begin | |
6664 | return | |
6665 | Make_Attribute_Reference (Loc, | |
6666 | Attribute_Name => Name_Last, | |
6667 | Prefix => | |
9dfe12ae | 6668 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 6669 | Expressions => New_List ( |
6670 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 6671 | end Get_N_Last; |
6672 | ||
6673 | ------------------ | |
6674 | -- Range_E_Cond -- | |
6675 | ------------------ | |
6676 | ||
6677 | function Range_E_Cond | |
6678 | (Exptyp : Entity_Id; | |
6679 | Typ : Entity_Id; | |
314a23b6 | 6680 | Indx : Nat) return Node_Id |
ee6ba406 | 6681 | is |
6682 | begin | |
6683 | return | |
6684 | Make_Or_Else (Loc, | |
6685 | Left_Opnd => | |
6686 | Make_Op_Lt (Loc, | |
3cb12758 | 6687 | Left_Opnd => |
6688 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First), | |
6689 | Right_Opnd => | |
6690 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
ee6ba406 | 6691 | |
6692 | Right_Opnd => | |
6693 | Make_Op_Gt (Loc, | |
3cb12758 | 6694 | Left_Opnd => |
6695 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last), | |
6696 | Right_Opnd => | |
6697 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 6698 | end Range_E_Cond; |
6699 | ||
6700 | ------------------------ | |
6701 | -- Range_Equal_E_Cond -- | |
6702 | ------------------------ | |
6703 | ||
6704 | function Range_Equal_E_Cond | |
6705 | (Exptyp : Entity_Id; | |
6706 | Typ : Entity_Id; | |
314a23b6 | 6707 | Indx : Nat) return Node_Id |
ee6ba406 | 6708 | is |
6709 | begin | |
6710 | return | |
6711 | Make_Or_Else (Loc, | |
6712 | Left_Opnd => | |
6713 | Make_Op_Ne (Loc, | |
3cb12758 | 6714 | Left_Opnd => |
6715 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First), | |
6716 | Right_Opnd => | |
6717 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
6718 | ||
ee6ba406 | 6719 | Right_Opnd => |
6720 | Make_Op_Ne (Loc, | |
3cb12758 | 6721 | Left_Opnd => |
6722 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last), | |
6723 | Right_Opnd => | |
6724 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 6725 | end Range_Equal_E_Cond; |
6726 | ||
6727 | ------------------ | |
6728 | -- Range_N_Cond -- | |
6729 | ------------------ | |
6730 | ||
6731 | function Range_N_Cond | |
6732 | (Expr : Node_Id; | |
6733 | Typ : Entity_Id; | |
314a23b6 | 6734 | Indx : Nat) return Node_Id |
ee6ba406 | 6735 | is |
6736 | begin | |
6737 | return | |
6738 | Make_Or_Else (Loc, | |
6739 | Left_Opnd => | |
6740 | Make_Op_Lt (Loc, | |
3cb12758 | 6741 | Left_Opnd => |
6742 | Get_N_First (Expr, Indx), | |
6743 | Right_Opnd => | |
6744 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
ee6ba406 | 6745 | |
6746 | Right_Opnd => | |
6747 | Make_Op_Gt (Loc, | |
3cb12758 | 6748 | Left_Opnd => |
6749 | Get_N_Last (Expr, Indx), | |
6750 | Right_Opnd => | |
6751 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 6752 | end Range_N_Cond; |
6753 | ||
6754 | -- Start of processing for Selected_Range_Checks | |
6755 | ||
6756 | begin | |
6757 | if not Expander_Active then | |
6758 | return Ret_Result; | |
6759 | end if; | |
6760 | ||
6761 | if Target_Typ = Any_Type | |
6762 | or else Target_Typ = Any_Composite | |
6763 | or else Raises_Constraint_Error (Ck_Node) | |
6764 | then | |
6765 | return Ret_Result; | |
6766 | end if; | |
6767 | ||
6768 | if No (Wnode) then | |
6769 | Wnode := Ck_Node; | |
6770 | end if; | |
6771 | ||
6772 | T_Typ := Target_Typ; | |
6773 | ||
6774 | if No (Source_Typ) then | |
6775 | S_Typ := Etype (Ck_Node); | |
6776 | else | |
6777 | S_Typ := Source_Typ; | |
6778 | end if; | |
6779 | ||
6780 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
6781 | return Ret_Result; | |
6782 | end if; | |
6783 | ||
6784 | -- The order of evaluating T_Typ before S_Typ seems to be critical | |
6785 | -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed | |
6786 | -- in, and since Node can be an N_Range node, it might be invalid. | |
6787 | -- Should there be an assert check somewhere for taking the Etype of | |
6788 | -- an N_Range node ??? | |
6789 | ||
6790 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
6791 | S_Typ := Designated_Type (S_Typ); | |
6792 | T_Typ := Designated_Type (T_Typ); | |
6793 | Do_Access := True; | |
6794 | ||
2af58f67 | 6795 | -- A simple optimization for the null case |
ee6ba406 | 6796 | |
2af58f67 | 6797 | if Known_Null (Ck_Node) then |
ee6ba406 | 6798 | return Ret_Result; |
6799 | end if; | |
6800 | end if; | |
6801 | ||
6802 | -- For an N_Range Node, check for a null range and then if not | |
6803 | -- null generate a range check action. | |
6804 | ||
6805 | if Nkind (Ck_Node) = N_Range then | |
6806 | ||
6807 | -- There's no point in checking a range against itself | |
6808 | ||
6809 | if Ck_Node = Scalar_Range (T_Typ) then | |
6810 | return Ret_Result; | |
6811 | end if; | |
6812 | ||
6813 | declare | |
6814 | T_LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
6815 | T_HB : constant Node_Id := Type_High_Bound (T_Typ); | |
eefa141b | 6816 | Known_T_LB : constant Boolean := Compile_Time_Known_Value (T_LB); |
6817 | Known_T_HB : constant Boolean := Compile_Time_Known_Value (T_HB); | |
ee6ba406 | 6818 | |
eefa141b | 6819 | LB : Node_Id := Low_Bound (Ck_Node); |
6820 | HB : Node_Id := High_Bound (Ck_Node); | |
6821 | Known_LB : Boolean; | |
6822 | Known_HB : Boolean; | |
6823 | ||
6824 | Null_Range : Boolean; | |
ee6ba406 | 6825 | Out_Of_Range_L : Boolean; |
6826 | Out_Of_Range_H : Boolean; | |
6827 | ||
6828 | begin | |
eefa141b | 6829 | -- Compute what is known at compile time |
6830 | ||
6831 | if Known_T_LB and Known_T_HB then | |
6832 | if Compile_Time_Known_Value (LB) then | |
6833 | Known_LB := True; | |
6834 | ||
6835 | -- There's no point in checking that a bound is within its | |
6836 | -- own range so pretend that it is known in this case. First | |
6837 | -- deal with low bound. | |
6838 | ||
6839 | elsif Ekind (Etype (LB)) = E_Signed_Integer_Subtype | |
6840 | and then Scalar_Range (Etype (LB)) = Scalar_Range (T_Typ) | |
6841 | then | |
6842 | LB := T_LB; | |
6843 | Known_LB := True; | |
6844 | ||
6845 | else | |
6846 | Known_LB := False; | |
6847 | end if; | |
6848 | ||
6849 | -- Likewise for the high bound | |
6850 | ||
6851 | if Compile_Time_Known_Value (HB) then | |
6852 | Known_HB := True; | |
6853 | ||
6854 | elsif Ekind (Etype (HB)) = E_Signed_Integer_Subtype | |
6855 | and then Scalar_Range (Etype (HB)) = Scalar_Range (T_Typ) | |
6856 | then | |
6857 | HB := T_HB; | |
6858 | Known_HB := True; | |
6859 | ||
6860 | else | |
6861 | Known_HB := False; | |
6862 | end if; | |
6863 | end if; | |
6864 | ||
6865 | -- Check for case where everything is static and we can do the | |
6866 | -- check at compile time. This is skipped if we have an access | |
6867 | -- type, since the access value may be null. | |
6868 | ||
6869 | -- ??? This code can be improved since you only need to know that | |
6870 | -- the two respective bounds (LB & T_LB or HB & T_HB) are known at | |
6871 | -- compile time to emit pertinent messages. | |
6872 | ||
6873 | if Known_T_LB and Known_T_HB and Known_LB and Known_HB | |
6874 | and not Do_Access | |
ee6ba406 | 6875 | then |
6876 | -- Floating-point case | |
6877 | ||
6878 | if Is_Floating_Point_Type (S_Typ) then | |
6879 | Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB); | |
6880 | Out_Of_Range_L := | |
6881 | (Expr_Value_R (LB) < Expr_Value_R (T_LB)) | |
eefa141b | 6882 | or else |
ee6ba406 | 6883 | (Expr_Value_R (LB) > Expr_Value_R (T_HB)); |
6884 | ||
6885 | Out_Of_Range_H := | |
6886 | (Expr_Value_R (HB) > Expr_Value_R (T_HB)) | |
eefa141b | 6887 | or else |
ee6ba406 | 6888 | (Expr_Value_R (HB) < Expr_Value_R (T_LB)); |
6889 | ||
6890 | -- Fixed or discrete type case | |
6891 | ||
6892 | else | |
6893 | Null_Range := Expr_Value (HB) < Expr_Value (LB); | |
6894 | Out_Of_Range_L := | |
6895 | (Expr_Value (LB) < Expr_Value (T_LB)) | |
eefa141b | 6896 | or else |
ee6ba406 | 6897 | (Expr_Value (LB) > Expr_Value (T_HB)); |
6898 | ||
6899 | Out_Of_Range_H := | |
6900 | (Expr_Value (HB) > Expr_Value (T_HB)) | |
eefa141b | 6901 | or else |
ee6ba406 | 6902 | (Expr_Value (HB) < Expr_Value (T_LB)); |
6903 | end if; | |
6904 | ||
6905 | if not Null_Range then | |
6906 | if Out_Of_Range_L then | |
6907 | if No (Warn_Node) then | |
6908 | Add_Check | |
6909 | (Compile_Time_Constraint_Error | |
6910 | (Low_Bound (Ck_Node), | |
6911 | "static value out of range of}?", T_Typ)); | |
6912 | ||
6913 | else | |
6914 | Add_Check | |
6915 | (Compile_Time_Constraint_Error | |
6916 | (Wnode, | |
6917 | "static range out of bounds of}?", T_Typ)); | |
6918 | end if; | |
6919 | end if; | |
6920 | ||
6921 | if Out_Of_Range_H then | |
6922 | if No (Warn_Node) then | |
6923 | Add_Check | |
6924 | (Compile_Time_Constraint_Error | |
6925 | (High_Bound (Ck_Node), | |
6926 | "static value out of range of}?", T_Typ)); | |
6927 | ||
6928 | else | |
6929 | Add_Check | |
6930 | (Compile_Time_Constraint_Error | |
6931 | (Wnode, | |
6932 | "static range out of bounds of}?", T_Typ)); | |
6933 | end if; | |
6934 | end if; | |
ee6ba406 | 6935 | end if; |
6936 | ||
6937 | else | |
6938 | declare | |
6939 | LB : Node_Id := Low_Bound (Ck_Node); | |
6940 | HB : Node_Id := High_Bound (Ck_Node); | |
6941 | ||
6942 | begin | |
feff2f05 | 6943 | -- If either bound is a discriminant and we are within the |
6944 | -- record declaration, it is a use of the discriminant in a | |
6945 | -- constraint of a component, and nothing can be checked | |
6946 | -- here. The check will be emitted within the init proc. | |
6947 | -- Before then, the discriminal has no real meaning. | |
6948 | -- Similarly, if the entity is a discriminal, there is no | |
6949 | -- check to perform yet. | |
6950 | ||
6951 | -- The same holds within a discriminated synchronized type, | |
6952 | -- where the discriminant may constrain a component or an | |
6953 | -- entry family. | |
ee6ba406 | 6954 | |
6955 | if Nkind (LB) = N_Identifier | |
0577b0b1 | 6956 | and then Denotes_Discriminant (LB, True) |
ee6ba406 | 6957 | then |
0577b0b1 | 6958 | if Current_Scope = Scope (Entity (LB)) |
6959 | or else Is_Concurrent_Type (Current_Scope) | |
6960 | or else Ekind (Entity (LB)) /= E_Discriminant | |
6961 | then | |
ee6ba406 | 6962 | return Ret_Result; |
6963 | else | |
6964 | LB := | |
6965 | New_Occurrence_Of (Discriminal (Entity (LB)), Loc); | |
6966 | end if; | |
6967 | end if; | |
6968 | ||
6969 | if Nkind (HB) = N_Identifier | |
0577b0b1 | 6970 | and then Denotes_Discriminant (HB, True) |
ee6ba406 | 6971 | then |
0577b0b1 | 6972 | if Current_Scope = Scope (Entity (HB)) |
6973 | or else Is_Concurrent_Type (Current_Scope) | |
6974 | or else Ekind (Entity (HB)) /= E_Discriminant | |
6975 | then | |
ee6ba406 | 6976 | return Ret_Result; |
6977 | else | |
6978 | HB := | |
6979 | New_Occurrence_Of (Discriminal (Entity (HB)), Loc); | |
6980 | end if; | |
6981 | end if; | |
6982 | ||
6983 | Cond := Discrete_Range_Cond (Ck_Node, T_Typ); | |
6984 | Set_Paren_Count (Cond, 1); | |
6985 | ||
6986 | Cond := | |
6987 | Make_And_Then (Loc, | |
6988 | Left_Opnd => | |
6989 | Make_Op_Ge (Loc, | |
9dfe12ae | 6990 | Left_Opnd => Duplicate_Subexpr_No_Checks (HB), |
6991 | Right_Opnd => Duplicate_Subexpr_No_Checks (LB)), | |
ee6ba406 | 6992 | Right_Opnd => Cond); |
6993 | end; | |
ee6ba406 | 6994 | end if; |
6995 | end; | |
6996 | ||
6997 | elsif Is_Scalar_Type (S_Typ) then | |
6998 | ||
6999 | -- This somewhat duplicates what Apply_Scalar_Range_Check does, | |
7000 | -- except the above simply sets a flag in the node and lets | |
7001 | -- gigi generate the check base on the Etype of the expression. | |
7002 | -- Sometimes, however we want to do a dynamic check against an | |
7003 | -- arbitrary target type, so we do that here. | |
7004 | ||
7005 | if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then | |
7006 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
7007 | ||
7008 | -- For literals, we can tell if the constraint error will be | |
7009 | -- raised at compile time, so we never need a dynamic check, but | |
7010 | -- if the exception will be raised, then post the usual warning, | |
7011 | -- and replace the literal with a raise constraint error | |
7012 | -- expression. As usual, skip this for access types | |
7013 | ||
7014 | elsif Compile_Time_Known_Value (Ck_Node) | |
7015 | and then not Do_Access | |
7016 | then | |
7017 | declare | |
7018 | LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
7019 | UB : constant Node_Id := Type_High_Bound (T_Typ); | |
7020 | ||
7021 | Out_Of_Range : Boolean; | |
7022 | Static_Bounds : constant Boolean := | |
7023 | Compile_Time_Known_Value (LB) | |
7024 | and Compile_Time_Known_Value (UB); | |
7025 | ||
7026 | begin | |
7027 | -- Following range tests should use Sem_Eval routine ??? | |
7028 | ||
7029 | if Static_Bounds then | |
7030 | if Is_Floating_Point_Type (S_Typ) then | |
7031 | Out_Of_Range := | |
7032 | (Expr_Value_R (Ck_Node) < Expr_Value_R (LB)) | |
7033 | or else | |
7034 | (Expr_Value_R (Ck_Node) > Expr_Value_R (UB)); | |
7035 | ||
eefa141b | 7036 | -- Fixed or discrete type |
7037 | ||
7038 | else | |
ee6ba406 | 7039 | Out_Of_Range := |
7040 | Expr_Value (Ck_Node) < Expr_Value (LB) | |
7041 | or else | |
7042 | Expr_Value (Ck_Node) > Expr_Value (UB); | |
7043 | end if; | |
7044 | ||
eefa141b | 7045 | -- Bounds of the type are static and the literal is out of |
7046 | -- range so output a warning message. | |
ee6ba406 | 7047 | |
7048 | if Out_Of_Range then | |
7049 | if No (Warn_Node) then | |
7050 | Add_Check | |
7051 | (Compile_Time_Constraint_Error | |
7052 | (Ck_Node, | |
7053 | "static value out of range of}?", T_Typ)); | |
7054 | ||
7055 | else | |
7056 | Add_Check | |
7057 | (Compile_Time_Constraint_Error | |
7058 | (Wnode, | |
7059 | "static value out of range of}?", T_Typ)); | |
7060 | end if; | |
7061 | end if; | |
7062 | ||
7063 | else | |
7064 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
7065 | end if; | |
7066 | end; | |
7067 | ||
7068 | -- Here for the case of a non-static expression, we need a runtime | |
7069 | -- check unless the source type range is guaranteed to be in the | |
7070 | -- range of the target type. | |
7071 | ||
7072 | else | |
7a1dabb3 | 7073 | if not In_Subrange_Of (S_Typ, T_Typ) then |
ee6ba406 | 7074 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); |
7075 | end if; | |
7076 | end if; | |
7077 | end if; | |
7078 | ||
7079 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
7080 | if Is_Constrained (T_Typ) then | |
7081 | ||
7082 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
7083 | Exptyp := Get_Actual_Subtype (Expr_Actual); | |
7084 | ||
7085 | if Is_Access_Type (Exptyp) then | |
7086 | Exptyp := Designated_Type (Exptyp); | |
7087 | end if; | |
7088 | ||
7089 | -- String_Literal case. This needs to be handled specially be- | |
7090 | -- cause no index types are available for string literals. The | |
7091 | -- condition is simply: | |
7092 | ||
7093 | -- T_Typ'Length = string-literal-length | |
7094 | ||
7095 | if Nkind (Expr_Actual) = N_String_Literal then | |
7096 | null; | |
7097 | ||
7098 | -- General array case. Here we have a usable actual subtype for | |
7099 | -- the expression, and the condition is built from the two types | |
7100 | ||
7101 | -- T_Typ'First < Exptyp'First or else | |
7102 | -- T_Typ'Last > Exptyp'Last or else | |
7103 | -- T_Typ'First(1) < Exptyp'First(1) or else | |
7104 | -- T_Typ'Last(1) > Exptyp'Last(1) or else | |
7105 | -- ... | |
7106 | ||
7107 | elsif Is_Constrained (Exptyp) then | |
7108 | declare | |
9dfe12ae | 7109 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
7110 | ||
ee6ba406 | 7111 | L_Index : Node_Id; |
7112 | R_Index : Node_Id; | |
ee6ba406 | 7113 | |
7114 | begin | |
7115 | L_Index := First_Index (T_Typ); | |
7116 | R_Index := First_Index (Exptyp); | |
7117 | ||
7118 | for Indx in 1 .. Ndims loop | |
7119 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 7120 | or else |
7121 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 7122 | then |
ee6ba406 | 7123 | -- Deal with compile time length check. Note that we |
7124 | -- skip this in the access case, because the access | |
7125 | -- value may be null, so we cannot know statically. | |
7126 | ||
7127 | if not | |
7128 | Subtypes_Statically_Match | |
7129 | (Etype (L_Index), Etype (R_Index)) | |
7130 | then | |
7131 | -- If the target type is constrained then we | |
7132 | -- have to check for exact equality of bounds | |
7133 | -- (required for qualified expressions). | |
7134 | ||
7135 | if Is_Constrained (T_Typ) then | |
7136 | Evolve_Or_Else | |
7137 | (Cond, | |
7138 | Range_Equal_E_Cond (Exptyp, T_Typ, Indx)); | |
ee6ba406 | 7139 | else |
7140 | Evolve_Or_Else | |
7141 | (Cond, Range_E_Cond (Exptyp, T_Typ, Indx)); | |
7142 | end if; | |
7143 | end if; | |
7144 | ||
7145 | Next (L_Index); | |
7146 | Next (R_Index); | |
ee6ba406 | 7147 | end if; |
7148 | end loop; | |
7149 | end; | |
7150 | ||
7151 | -- Handle cases where we do not get a usable actual subtype that | |
7152 | -- is constrained. This happens for example in the function call | |
7153 | -- and explicit dereference cases. In these cases, we have to get | |
7154 | -- the length or range from the expression itself, making sure we | |
7155 | -- do not evaluate it more than once. | |
7156 | ||
7157 | -- Here Ck_Node is the original expression, or more properly the | |
7158 | -- result of applying Duplicate_Expr to the original tree, | |
7159 | -- forcing the result to be a name. | |
7160 | ||
7161 | else | |
7162 | declare | |
9dfe12ae | 7163 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 7164 | |
7165 | begin | |
7166 | -- Build the condition for the explicit dereference case | |
7167 | ||
7168 | for Indx in 1 .. Ndims loop | |
7169 | Evolve_Or_Else | |
7170 | (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx)); | |
7171 | end loop; | |
7172 | end; | |
ee6ba406 | 7173 | end if; |
7174 | ||
7175 | else | |
feff2f05 | 7176 | -- For a conversion to an unconstrained array type, generate an |
7177 | -- Action to check that the bounds of the source value are within | |
7178 | -- the constraints imposed by the target type (RM 4.6(38)). No | |
7179 | -- check is needed for a conversion to an access to unconstrained | |
7180 | -- array type, as 4.6(24.15/2) requires the designated subtypes | |
7181 | -- of the two access types to statically match. | |
7182 | ||
7183 | if Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
7184 | and then not Do_Access | |
7185 | then | |
ee6ba406 | 7186 | declare |
7187 | Opnd_Index : Node_Id; | |
7188 | Targ_Index : Node_Id; | |
00c403ee | 7189 | Opnd_Range : Node_Id; |
ee6ba406 | 7190 | |
7191 | begin | |
feff2f05 | 7192 | Opnd_Index := First_Index (Get_Actual_Subtype (Ck_Node)); |
ee6ba406 | 7193 | Targ_Index := First_Index (T_Typ); |
00c403ee | 7194 | while Present (Opnd_Index) loop |
7195 | ||
7196 | -- If the index is a range, use its bounds. If it is an | |
7197 | -- entity (as will be the case if it is a named subtype | |
7198 | -- or an itype created for a slice) retrieve its range. | |
7199 | ||
7200 | if Is_Entity_Name (Opnd_Index) | |
7201 | and then Is_Type (Entity (Opnd_Index)) | |
7202 | then | |
7203 | Opnd_Range := Scalar_Range (Entity (Opnd_Index)); | |
7204 | else | |
7205 | Opnd_Range := Opnd_Index; | |
7206 | end if; | |
7207 | ||
7208 | if Nkind (Opnd_Range) = N_Range then | |
9c486805 | 7209 | if Is_In_Range |
7210 | (Low_Bound (Opnd_Range), Etype (Targ_Index), | |
7211 | Assume_Valid => True) | |
ee6ba406 | 7212 | and then |
7213 | Is_In_Range | |
9c486805 | 7214 | (High_Bound (Opnd_Range), Etype (Targ_Index), |
7215 | Assume_Valid => True) | |
ee6ba406 | 7216 | then |
7217 | null; | |
7218 | ||
feff2f05 | 7219 | -- If null range, no check needed |
f2a06be9 | 7220 | |
9dfe12ae | 7221 | elsif |
00c403ee | 7222 | Compile_Time_Known_Value (High_Bound (Opnd_Range)) |
9dfe12ae | 7223 | and then |
00c403ee | 7224 | Compile_Time_Known_Value (Low_Bound (Opnd_Range)) |
9dfe12ae | 7225 | and then |
00c403ee | 7226 | Expr_Value (High_Bound (Opnd_Range)) < |
7227 | Expr_Value (Low_Bound (Opnd_Range)) | |
9dfe12ae | 7228 | then |
7229 | null; | |
7230 | ||
ee6ba406 | 7231 | elsif Is_Out_Of_Range |
9c486805 | 7232 | (Low_Bound (Opnd_Range), Etype (Targ_Index), |
7233 | Assume_Valid => True) | |
ee6ba406 | 7234 | or else |
7235 | Is_Out_Of_Range | |
9c486805 | 7236 | (High_Bound (Opnd_Range), Etype (Targ_Index), |
7237 | Assume_Valid => True) | |
ee6ba406 | 7238 | then |
7239 | Add_Check | |
7240 | (Compile_Time_Constraint_Error | |
7241 | (Wnode, "value out of range of}?", T_Typ)); | |
7242 | ||
7243 | else | |
7244 | Evolve_Or_Else | |
7245 | (Cond, | |
7246 | Discrete_Range_Cond | |
00c403ee | 7247 | (Opnd_Range, Etype (Targ_Index))); |
ee6ba406 | 7248 | end if; |
7249 | end if; | |
7250 | ||
7251 | Next_Index (Opnd_Index); | |
7252 | Next_Index (Targ_Index); | |
7253 | end loop; | |
7254 | end; | |
7255 | end if; | |
7256 | end if; | |
7257 | end if; | |
7258 | ||
7259 | -- Construct the test and insert into the tree | |
7260 | ||
7261 | if Present (Cond) then | |
7262 | if Do_Access then | |
7263 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
7264 | end if; | |
7265 | ||
f15731c4 | 7266 | Add_Check |
7267 | (Make_Raise_Constraint_Error (Loc, | |
eefa141b | 7268 | Condition => Cond, |
7269 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 7270 | end if; |
7271 | ||
7272 | return Ret_Result; | |
ee6ba406 | 7273 | end Selected_Range_Checks; |
7274 | ||
7275 | ------------------------------- | |
7276 | -- Storage_Checks_Suppressed -- | |
7277 | ------------------------------- | |
7278 | ||
7279 | function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is | |
7280 | begin | |
9dfe12ae | 7281 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
7282 | return Is_Check_Suppressed (E, Storage_Check); | |
7283 | else | |
7284 | return Scope_Suppress (Storage_Check); | |
7285 | end if; | |
ee6ba406 | 7286 | end Storage_Checks_Suppressed; |
7287 | ||
7288 | --------------------------- | |
7289 | -- Tag_Checks_Suppressed -- | |
7290 | --------------------------- | |
7291 | ||
7292 | function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is | |
7293 | begin | |
9dfe12ae | 7294 | if Present (E) then |
7295 | if Kill_Tag_Checks (E) then | |
7296 | return True; | |
7297 | elsif Checks_May_Be_Suppressed (E) then | |
7298 | return Is_Check_Suppressed (E, Tag_Check); | |
7299 | end if; | |
7300 | end if; | |
7301 | ||
7302 | return Scope_Suppress (Tag_Check); | |
ee6ba406 | 7303 | end Tag_Checks_Suppressed; |
7304 | ||
0577b0b1 | 7305 | -------------------------- |
7306 | -- Validity_Check_Range -- | |
7307 | -------------------------- | |
7308 | ||
7309 | procedure Validity_Check_Range (N : Node_Id) is | |
7310 | begin | |
7311 | if Validity_Checks_On and Validity_Check_Operands then | |
7312 | if Nkind (N) = N_Range then | |
7313 | Ensure_Valid (Low_Bound (N)); | |
7314 | Ensure_Valid (High_Bound (N)); | |
7315 | end if; | |
7316 | end if; | |
7317 | end Validity_Check_Range; | |
7318 | ||
7319 | -------------------------------- | |
7320 | -- Validity_Checks_Suppressed -- | |
7321 | -------------------------------- | |
7322 | ||
7323 | function Validity_Checks_Suppressed (E : Entity_Id) return Boolean is | |
7324 | begin | |
7325 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
7326 | return Is_Check_Suppressed (E, Validity_Check); | |
7327 | else | |
7328 | return Scope_Suppress (Validity_Check); | |
7329 | end if; | |
7330 | end Validity_Checks_Suppressed; | |
7331 | ||
ee6ba406 | 7332 | end Checks; |