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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 | -- -- | |
86594966 | 9 | -- Copyright (C) 1992-2013, 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; |
301d5ec3 | 34 | with Exp_Tss; use Exp_Tss; |
ee6ba406 | 35 | with Exp_Util; use Exp_Util; |
36 | with Elists; use Elists; | |
4fb5f0a0 | 37 | with Expander; use Expander; |
5329ca64 | 38 | with Eval_Fat; use Eval_Fat; |
ee6ba406 | 39 | with Freeze; use Freeze; |
9dfe12ae | 40 | with Lib; use Lib; |
ee6ba406 | 41 | with Nlists; use Nlists; |
42 | with Nmake; use Nmake; | |
43 | with Opt; use Opt; | |
9dfe12ae | 44 | with Output; use Output; |
c2b56224 | 45 | with Restrict; use Restrict; |
1e16c51c | 46 | with Rident; use Rident; |
ee6ba406 | 47 | with Rtsfind; use Rtsfind; |
48 | with Sem; use Sem; | |
d60c9ff7 | 49 | with Sem_Aux; use Sem_Aux; |
ee6ba406 | 50 | with Sem_Eval; use Sem_Eval; |
00f91aef | 51 | with Sem_Ch3; use Sem_Ch3; |
9dfe12ae | 52 | with Sem_Ch8; use Sem_Ch8; |
ee6ba406 | 53 | with Sem_Res; use Sem_Res; |
54 | with Sem_Util; use Sem_Util; | |
55 | with Sem_Warn; use Sem_Warn; | |
56 | with Sinfo; use Sinfo; | |
9dfe12ae | 57 | with Sinput; use Sinput; |
ee6ba406 | 58 | with Snames; use Snames; |
9dfe12ae | 59 | with Sprint; use Sprint; |
ee6ba406 | 60 | with Stand; use Stand; |
f15731c4 | 61 | with Targparm; use Targparm; |
ee6ba406 | 62 | with Tbuild; use Tbuild; |
63 | with Ttypes; use Ttypes; | |
64 | with Urealp; use Urealp; | |
65 | with Validsw; use Validsw; | |
66 | ||
67 | package body Checks is | |
68 | ||
69 | -- General note: many of these routines are concerned with generating | |
70 | -- checking code to make sure that constraint error is raised at runtime. | |
71 | -- Clearly this code is only needed if the expander is active, since | |
72 | -- otherwise we will not be generating code or going into the runtime | |
73 | -- execution anyway. | |
74 | ||
75 | -- We therefore disconnect most of these checks if the expander is | |
76 | -- inactive. This has the additional benefit that we do not need to | |
77 | -- worry about the tree being messed up by previous errors (since errors | |
78 | -- turn off expansion anyway). | |
79 | ||
80 | -- There are a few exceptions to the above rule. For instance routines | |
81 | -- such as Apply_Scalar_Range_Check that do not insert any code can be | |
82 | -- safely called even when the Expander is inactive (but Errors_Detected | |
83 | -- is 0). The benefit of executing this code when expansion is off, is | |
84 | -- the ability to emit constraint error warning for static expressions | |
85 | -- even when we are not generating code. | |
86 | ||
9dfe12ae | 87 | ------------------------------------- |
88 | -- Suppression of Redundant Checks -- | |
89 | ------------------------------------- | |
90 | ||
91 | -- This unit implements a limited circuit for removal of redundant | |
92 | -- checks. The processing is based on a tracing of simple sequential | |
93 | -- flow. For any sequence of statements, we save expressions that are | |
94 | -- marked to be checked, and then if the same expression appears later | |
95 | -- with the same check, then under certain circumstances, the second | |
96 | -- check can be suppressed. | |
97 | ||
98 | -- Basically, we can suppress the check if we know for certain that | |
99 | -- the previous expression has been elaborated (together with its | |
100 | -- check), and we know that the exception frame is the same, and that | |
101 | -- nothing has happened to change the result of the exception. | |
102 | ||
103 | -- Let us examine each of these three conditions in turn to describe | |
104 | -- how we ensure that this condition is met. | |
105 | ||
106 | -- First, we need to know for certain that the previous expression has | |
6fb3c314 | 107 | -- been executed. This is done principally by the mechanism of calling |
9dfe12ae | 108 | -- Conditional_Statements_Begin at the start of any statement sequence |
109 | -- and Conditional_Statements_End at the end. The End call causes all | |
110 | -- checks remembered since the Begin call to be discarded. This does | |
111 | -- miss a few cases, notably the case of a nested BEGIN-END block with | |
112 | -- no exception handlers. But the important thing is to be conservative. | |
113 | -- The other protection is that all checks are discarded if a label | |
114 | -- is encountered, since then the assumption of sequential execution | |
115 | -- is violated, and we don't know enough about the flow. | |
116 | ||
117 | -- Second, we need to know that the exception frame is the same. We | |
118 | -- do this by killing all remembered checks when we enter a new frame. | |
119 | -- Again, that's over-conservative, but generally the cases we can help | |
120 | -- with are pretty local anyway (like the body of a loop for example). | |
121 | ||
122 | -- Third, we must be sure to forget any checks which are no longer valid. | |
123 | -- This is done by two mechanisms, first the Kill_Checks_Variable call is | |
124 | -- used to note any changes to local variables. We only attempt to deal | |
125 | -- with checks involving local variables, so we do not need to worry | |
126 | -- about global variables. Second, a call to any non-global procedure | |
127 | -- causes us to abandon all stored checks, since such a all may affect | |
128 | -- the values of any local variables. | |
129 | ||
130 | -- The following define the data structures used to deal with remembering | |
131 | -- checks so that redundant checks can be eliminated as described above. | |
132 | ||
133 | -- Right now, the only expressions that we deal with are of the form of | |
134 | -- simple local objects (either declared locally, or IN parameters) or | |
135 | -- such objects plus/minus a compile time known constant. We can do | |
136 | -- more later on if it seems worthwhile, but this catches many simple | |
137 | -- cases in practice. | |
138 | ||
139 | -- The following record type reflects a single saved check. An entry | |
140 | -- is made in the stack of saved checks if and only if the expression | |
141 | -- has been elaborated with the indicated checks. | |
142 | ||
143 | type Saved_Check is record | |
144 | Killed : Boolean; | |
145 | -- Set True if entry is killed by Kill_Checks | |
146 | ||
147 | Entity : Entity_Id; | |
148 | -- The entity involved in the expression that is checked | |
149 | ||
150 | Offset : Uint; | |
151 | -- A compile time value indicating the result of adding or | |
152 | -- subtracting a compile time value. This value is to be | |
153 | -- added to the value of the Entity. A value of zero is | |
154 | -- used for the case of a simple entity reference. | |
155 | ||
156 | Check_Type : Character; | |
157 | -- This is set to 'R' for a range check (in which case Target_Type | |
158 | -- is set to the target type for the range check) or to 'O' for an | |
159 | -- overflow check (in which case Target_Type is set to Empty). | |
160 | ||
161 | Target_Type : Entity_Id; | |
162 | -- Used only if Do_Range_Check is set. Records the target type for | |
163 | -- the check. We need this, because a check is a duplicate only if | |
6fb3c314 | 164 | -- it has the same target type (or more accurately one with a |
9dfe12ae | 165 | -- range that is smaller or equal to the stored target type of a |
166 | -- saved check). | |
167 | end record; | |
168 | ||
169 | -- The following table keeps track of saved checks. Rather than use an | |
170 | -- extensible table. We just use a table of fixed size, and we discard | |
171 | -- any saved checks that do not fit. That's very unlikely to happen and | |
172 | -- this is only an optimization in any case. | |
173 | ||
174 | Saved_Checks : array (Int range 1 .. 200) of Saved_Check; | |
175 | -- Array of saved checks | |
176 | ||
177 | Num_Saved_Checks : Nat := 0; | |
178 | -- Number of saved checks | |
179 | ||
180 | -- The following stack keeps track of statement ranges. It is treated | |
181 | -- as a stack. When Conditional_Statements_Begin is called, an entry | |
182 | -- is pushed onto this stack containing the value of Num_Saved_Checks | |
183 | -- at the time of the call. Then when Conditional_Statements_End is | |
184 | -- called, this value is popped off and used to reset Num_Saved_Checks. | |
185 | ||
186 | -- Note: again, this is a fixed length stack with a size that should | |
187 | -- always be fine. If the value of the stack pointer goes above the | |
188 | -- limit, then we just forget all saved checks. | |
189 | ||
190 | Saved_Checks_Stack : array (Int range 1 .. 100) of Nat; | |
191 | Saved_Checks_TOS : Nat := 0; | |
192 | ||
193 | ----------------------- | |
194 | -- Local Subprograms -- | |
195 | ----------------------- | |
ee6ba406 | 196 | |
0df9d43f | 197 | procedure Apply_Arithmetic_Overflow_Strict (N : Node_Id); |
3cce7f32 | 198 | -- Used to apply arithmetic overflow checks for all cases except operators |
691fe9e0 | 199 | -- on signed arithmetic types in MINIMIZED/ELIMINATED case (for which we |
0df9d43f | 200 | -- call Apply_Arithmetic_Overflow_Minimized_Eliminated below). N can be a |
201 | -- signed integer arithmetic operator (but not an if or case expression). | |
202 | -- It is also called for types other than signed integers. | |
3cce7f32 | 203 | |
204 | procedure Apply_Arithmetic_Overflow_Minimized_Eliminated (Op : Node_Id); | |
205 | -- Used to apply arithmetic overflow checks for the case where the overflow | |
0df9d43f | 206 | -- checking mode is MINIMIZED or ELIMINATED and we have a signed integer |
207 | -- arithmetic op (which includes the case of if and case expressions). Note | |
208 | -- that Do_Overflow_Check may or may not be set for node Op. In these modes | |
209 | -- we have work to do even if overflow checking is suppressed. | |
3cce7f32 | 210 | |
2fe22c69 | 211 | procedure Apply_Division_Check |
212 | (N : Node_Id; | |
213 | Rlo : Uint; | |
214 | Rhi : Uint; | |
215 | ROK : Boolean); | |
216 | -- N is an N_Op_Div, N_Op_Rem, or N_Op_Mod node. This routine applies | |
217 | -- division checks as required if the Do_Division_Check flag is set. | |
218 | -- Rlo and Rhi give the possible range of the right operand, these values | |
219 | -- can be referenced and trusted only if ROK is set True. | |
220 | ||
221 | procedure Apply_Float_Conversion_Check | |
222 | (Ck_Node : Node_Id; | |
223 | Target_Typ : Entity_Id); | |
224 | -- The checks on a conversion from a floating-point type to an integer | |
225 | -- type are delicate. They have to be performed before conversion, they | |
226 | -- have to raise an exception when the operand is a NaN, and rounding must | |
227 | -- be taken into account to determine the safe bounds of the operand. | |
228 | ||
ee6ba406 | 229 | procedure Apply_Selected_Length_Checks |
230 | (Ck_Node : Node_Id; | |
231 | Target_Typ : Entity_Id; | |
232 | Source_Typ : Entity_Id; | |
233 | Do_Static : Boolean); | |
234 | -- This is the subprogram that does all the work for Apply_Length_Check | |
235 | -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as | |
236 | -- described for the above routines. The Do_Static flag indicates that | |
237 | -- only a static check is to be done. | |
238 | ||
239 | procedure Apply_Selected_Range_Checks | |
240 | (Ck_Node : Node_Id; | |
241 | Target_Typ : Entity_Id; | |
242 | Source_Typ : Entity_Id; | |
243 | Do_Static : Boolean); | |
244 | -- This is the subprogram that does all the work for Apply_Range_Check. | |
245 | -- Expr, Target_Typ and Source_Typ are as described for the above | |
246 | -- routine. The Do_Static flag indicates that only a static check is | |
247 | -- to be done. | |
248 | ||
2af58f67 | 249 | type Check_Type is new Check_Id range Access_Check .. Division_Check; |
13dbf220 | 250 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean; |
251 | -- This function is used to see if an access or division by zero check is | |
252 | -- needed. The check is to be applied to a single variable appearing in the | |
253 | -- source, and N is the node for the reference. If N is not of this form, | |
254 | -- True is returned with no further processing. If N is of the right form, | |
255 | -- then further processing determines if the given Check is needed. | |
256 | -- | |
257 | -- The particular circuit is to see if we have the case of a check that is | |
258 | -- not needed because it appears in the right operand of a short circuited | |
259 | -- conditional where the left operand guards the check. For example: | |
260 | -- | |
261 | -- if Var = 0 or else Q / Var > 12 then | |
262 | -- ... | |
263 | -- end if; | |
264 | -- | |
265 | -- In this example, the division check is not required. At the same time | |
266 | -- we can issue warnings for suspicious use of non-short-circuited forms, | |
267 | -- such as: | |
268 | -- | |
269 | -- if Var = 0 or Q / Var > 12 then | |
270 | -- ... | |
271 | -- end if; | |
272 | ||
9dfe12ae | 273 | procedure Find_Check |
274 | (Expr : Node_Id; | |
275 | Check_Type : Character; | |
276 | Target_Type : Entity_Id; | |
277 | Entry_OK : out Boolean; | |
278 | Check_Num : out Nat; | |
279 | Ent : out Entity_Id; | |
280 | Ofs : out Uint); | |
281 | -- This routine is used by Enable_Range_Check and Enable_Overflow_Check | |
282 | -- to see if a check is of the form for optimization, and if so, to see | |
283 | -- if it has already been performed. Expr is the expression to check, | |
284 | -- and Check_Type is 'R' for a range check, 'O' for an overflow check. | |
285 | -- Target_Type is the target type for a range check, and Empty for an | |
286 | -- overflow check. If the entry is not of the form for optimization, | |
287 | -- then Entry_OK is set to False, and the remaining out parameters | |
288 | -- are undefined. If the entry is OK, then Ent/Ofs are set to the | |
289 | -- entity and offset from the expression. Check_Num is the number of | |
290 | -- a matching saved entry in Saved_Checks, or zero if no such entry | |
291 | -- is located. | |
292 | ||
ee6ba406 | 293 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id; |
294 | -- If a discriminal is used in constraining a prival, Return reference | |
295 | -- to the discriminal of the protected body (which renames the parameter | |
296 | -- of the enclosing protected operation). This clumsy transformation is | |
297 | -- needed because privals are created too late and their actual subtypes | |
298 | -- are not available when analysing the bodies of the protected operations. | |
0577b0b1 | 299 | -- This function is called whenever the bound is an entity and the scope |
300 | -- indicates a protected operation. If the bound is an in-parameter of | |
301 | -- a protected operation that is not a prival, the function returns the | |
302 | -- bound itself. | |
ee6ba406 | 303 | -- To be cleaned up??? |
304 | ||
305 | function Guard_Access | |
306 | (Cond : Node_Id; | |
307 | Loc : Source_Ptr; | |
314a23b6 | 308 | Ck_Node : Node_Id) return Node_Id; |
ee6ba406 | 309 | -- In the access type case, guard the test with a test to ensure |
310 | -- that the access value is non-null, since the checks do not | |
311 | -- not apply to null access values. | |
312 | ||
313 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr); | |
314 | -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the | |
315 | -- Constraint_Error node. | |
316 | ||
3cce7f32 | 317 | function Is_Signed_Integer_Arithmetic_Op (N : Node_Id) return Boolean; |
318 | -- Returns True if node N is for an arithmetic operation with signed | |
0326b4d4 | 319 | -- integer operands. This includes unary and binary operators, and also |
320 | -- if and case expression nodes where the dependent expressions are of | |
321 | -- a signed integer type. These are the kinds of nodes for which special | |
691fe9e0 | 322 | -- handling applies in MINIMIZED or ELIMINATED overflow checking mode. |
3cce7f32 | 323 | |
0577b0b1 | 324 | function Range_Or_Validity_Checks_Suppressed |
325 | (Expr : Node_Id) return Boolean; | |
326 | -- Returns True if either range or validity checks or both are suppressed | |
327 | -- for the type of the given expression, or, if the expression is the name | |
328 | -- of an entity, if these checks are suppressed for the entity. | |
329 | ||
ee6ba406 | 330 | function Selected_Length_Checks |
331 | (Ck_Node : Node_Id; | |
332 | Target_Typ : Entity_Id; | |
333 | Source_Typ : Entity_Id; | |
314a23b6 | 334 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 335 | -- Like Apply_Selected_Length_Checks, except it doesn't modify |
336 | -- anything, just returns a list of nodes as described in the spec of | |
337 | -- this package for the Range_Check function. | |
338 | ||
339 | function Selected_Range_Checks | |
340 | (Ck_Node : Node_Id; | |
341 | Target_Typ : Entity_Id; | |
342 | Source_Typ : Entity_Id; | |
314a23b6 | 343 | Warn_Node : Node_Id) return Check_Result; |
ee6ba406 | 344 | -- Like Apply_Selected_Range_Checks, except it doesn't modify anything, |
345 | -- just returns a list of nodes as described in the spec of this package | |
346 | -- for the Range_Check function. | |
347 | ||
348 | ------------------------------ | |
349 | -- Access_Checks_Suppressed -- | |
350 | ------------------------------ | |
351 | ||
352 | function Access_Checks_Suppressed (E : Entity_Id) return Boolean is | |
353 | begin | |
9dfe12ae | 354 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
355 | return Is_Check_Suppressed (E, Access_Check); | |
356 | else | |
fafc6b97 | 357 | return Scope_Suppress.Suppress (Access_Check); |
9dfe12ae | 358 | end if; |
ee6ba406 | 359 | end Access_Checks_Suppressed; |
360 | ||
361 | ------------------------------------- | |
362 | -- Accessibility_Checks_Suppressed -- | |
363 | ------------------------------------- | |
364 | ||
365 | function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is | |
366 | begin | |
9dfe12ae | 367 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
368 | return Is_Check_Suppressed (E, Accessibility_Check); | |
369 | else | |
fafc6b97 | 370 | return Scope_Suppress.Suppress (Accessibility_Check); |
9dfe12ae | 371 | end if; |
ee6ba406 | 372 | end Accessibility_Checks_Suppressed; |
373 | ||
00c403ee | 374 | ----------------------------- |
375 | -- Activate_Division_Check -- | |
376 | ----------------------------- | |
377 | ||
378 | procedure Activate_Division_Check (N : Node_Id) is | |
379 | begin | |
380 | Set_Do_Division_Check (N, True); | |
381 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
382 | end Activate_Division_Check; | |
383 | ||
384 | ----------------------------- | |
385 | -- Activate_Overflow_Check -- | |
386 | ----------------------------- | |
387 | ||
388 | procedure Activate_Overflow_Check (N : Node_Id) is | |
389 | begin | |
d32ceaf3 | 390 | if not Nkind_In (N, N_Op_Rem, N_Op_Mod, N_Op_Plus) then |
391 | Set_Do_Overflow_Check (N, True); | |
392 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
393 | end if; | |
00c403ee | 394 | end Activate_Overflow_Check; |
395 | ||
396 | -------------------------- | |
397 | -- Activate_Range_Check -- | |
398 | -------------------------- | |
399 | ||
400 | procedure Activate_Range_Check (N : Node_Id) is | |
401 | begin | |
402 | Set_Do_Range_Check (N, True); | |
403 | Possible_Local_Raise (N, Standard_Constraint_Error); | |
404 | end Activate_Range_Check; | |
405 | ||
0577b0b1 | 406 | --------------------------------- |
407 | -- Alignment_Checks_Suppressed -- | |
408 | --------------------------------- | |
409 | ||
410 | function Alignment_Checks_Suppressed (E : Entity_Id) return Boolean is | |
411 | begin | |
412 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
413 | return Is_Check_Suppressed (E, Alignment_Check); | |
414 | else | |
fafc6b97 | 415 | return Scope_Suppress.Suppress (Alignment_Check); |
0577b0b1 | 416 | end if; |
417 | end Alignment_Checks_Suppressed; | |
418 | ||
ee6ba406 | 419 | ------------------------- |
420 | -- Append_Range_Checks -- | |
421 | ------------------------- | |
422 | ||
423 | procedure Append_Range_Checks | |
424 | (Checks : Check_Result; | |
425 | Stmts : List_Id; | |
426 | Suppress_Typ : Entity_Id; | |
427 | Static_Sloc : Source_Ptr; | |
428 | Flag_Node : Node_Id) | |
429 | is | |
9dfe12ae | 430 | Internal_Flag_Node : constant Node_Id := Flag_Node; |
431 | Internal_Static_Sloc : constant Source_Ptr := Static_Sloc; | |
432 | ||
ee6ba406 | 433 | Checks_On : constant Boolean := |
b6341c67 | 434 | (not Index_Checks_Suppressed (Suppress_Typ)) |
435 | or else (not Range_Checks_Suppressed (Suppress_Typ)); | |
ee6ba406 | 436 | |
437 | begin | |
438 | -- For now we just return if Checks_On is false, however this should | |
439 | -- be enhanced to check for an always True value in the condition | |
440 | -- and to generate a compilation warning??? | |
441 | ||
442 | if not Checks_On then | |
443 | return; | |
444 | end if; | |
445 | ||
446 | for J in 1 .. 2 loop | |
447 | exit when No (Checks (J)); | |
448 | ||
449 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
450 | and then Present (Condition (Checks (J))) | |
451 | then | |
452 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
453 | Append_To (Stmts, Checks (J)); | |
454 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
455 | end if; | |
456 | ||
457 | else | |
458 | Append_To | |
f15731c4 | 459 | (Stmts, |
460 | Make_Raise_Constraint_Error (Internal_Static_Sloc, | |
461 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 462 | end if; |
463 | end loop; | |
464 | end Append_Range_Checks; | |
465 | ||
466 | ------------------------ | |
467 | -- Apply_Access_Check -- | |
468 | ------------------------ | |
469 | ||
470 | procedure Apply_Access_Check (N : Node_Id) is | |
471 | P : constant Node_Id := Prefix (N); | |
472 | ||
473 | begin | |
13dbf220 | 474 | -- We do not need checks if we are not generating code (i.e. the |
475 | -- expander is not active). This is not just an optimization, there | |
476 | -- are cases (e.g. with pragma Debug) where generating the checks | |
477 | -- can cause real trouble). | |
284faf8b | 478 | |
6dbcfcd9 | 479 | if not Full_Expander_Active then |
13dbf220 | 480 | return; |
9dfe12ae | 481 | end if; |
ee6ba406 | 482 | |
84d0d4a5 | 483 | -- No check if short circuiting makes check unnecessary |
9dfe12ae | 484 | |
84d0d4a5 | 485 | if not Check_Needed (P, Access_Check) then |
486 | return; | |
ee6ba406 | 487 | end if; |
9dfe12ae | 488 | |
cc60bd16 | 489 | -- No check if accessing the Offset_To_Top component of a dispatch |
490 | -- table. They are safe by construction. | |
491 | ||
040277b1 | 492 | if Tagged_Type_Expansion |
493 | and then Present (Etype (P)) | |
cc60bd16 | 494 | and then RTU_Loaded (Ada_Tags) |
495 | and then RTE_Available (RE_Offset_To_Top_Ptr) | |
496 | and then Etype (P) = RTE (RE_Offset_To_Top_Ptr) | |
497 | then | |
498 | return; | |
499 | end if; | |
500 | ||
84d0d4a5 | 501 | -- Otherwise go ahead and install the check |
9dfe12ae | 502 | |
fa7497e8 | 503 | Install_Null_Excluding_Check (P); |
ee6ba406 | 504 | end Apply_Access_Check; |
505 | ||
506 | ------------------------------- | |
507 | -- Apply_Accessibility_Check -- | |
508 | ------------------------------- | |
509 | ||
55dc6dc2 | 510 | procedure Apply_Accessibility_Check |
511 | (N : Node_Id; | |
512 | Typ : Entity_Id; | |
513 | Insert_Node : Node_Id) | |
514 | is | |
ee6ba406 | 515 | Loc : constant Source_Ptr := Sloc (N); |
1a9cc6cd | 516 | Param_Ent : Entity_Id := Param_Entity (N); |
ee6ba406 | 517 | Param_Level : Node_Id; |
518 | Type_Level : Node_Id; | |
519 | ||
520 | begin | |
47d210a3 | 521 | if Ada_Version >= Ada_2012 |
522 | and then not Present (Param_Ent) | |
523 | and then Is_Entity_Name (N) | |
524 | and then Ekind_In (Entity (N), E_Constant, E_Variable) | |
525 | and then Present (Effective_Extra_Accessibility (Entity (N))) | |
526 | then | |
527 | Param_Ent := Entity (N); | |
528 | while Present (Renamed_Object (Param_Ent)) loop | |
1a9cc6cd | 529 | |
47d210a3 | 530 | -- Renamed_Object must return an Entity_Name here |
531 | -- because of preceding "Present (E_E_A (...))" test. | |
532 | ||
533 | Param_Ent := Entity (Renamed_Object (Param_Ent)); | |
534 | end loop; | |
535 | end if; | |
536 | ||
ee6ba406 | 537 | if Inside_A_Generic then |
538 | return; | |
539 | ||
6ffc64fc | 540 | -- Only apply the run-time check if the access parameter has an |
541 | -- associated extra access level parameter and when the level of the | |
542 | -- type is less deep than the level of the access parameter, and | |
543 | -- accessibility checks are not suppressed. | |
ee6ba406 | 544 | |
545 | elsif Present (Param_Ent) | |
546 | and then Present (Extra_Accessibility (Param_Ent)) | |
47d210a3 | 547 | and then UI_Gt (Object_Access_Level (N), |
1a9cc6cd | 548 | Deepest_Type_Access_Level (Typ)) |
ee6ba406 | 549 | and then not Accessibility_Checks_Suppressed (Param_Ent) |
550 | and then not Accessibility_Checks_Suppressed (Typ) | |
551 | then | |
552 | Param_Level := | |
553 | New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc); | |
554 | ||
1a9cc6cd | 555 | Type_Level := |
556 | Make_Integer_Literal (Loc, Deepest_Type_Access_Level (Typ)); | |
ee6ba406 | 557 | |
bf3e1520 | 558 | -- Raise Program_Error if the accessibility level of the access |
84d0d4a5 | 559 | -- parameter is deeper than the level of the target access type. |
ee6ba406 | 560 | |
55dc6dc2 | 561 | Insert_Action (Insert_Node, |
ee6ba406 | 562 | Make_Raise_Program_Error (Loc, |
563 | Condition => | |
564 | Make_Op_Gt (Loc, | |
565 | Left_Opnd => Param_Level, | |
f15731c4 | 566 | Right_Opnd => Type_Level), |
567 | Reason => PE_Accessibility_Check_Failed)); | |
ee6ba406 | 568 | |
569 | Analyze_And_Resolve (N); | |
570 | end if; | |
571 | end Apply_Accessibility_Check; | |
572 | ||
0577b0b1 | 573 | -------------------------------- |
574 | -- Apply_Address_Clause_Check -- | |
575 | -------------------------------- | |
576 | ||
577 | procedure Apply_Address_Clause_Check (E : Entity_Id; N : Node_Id) is | |
d950dc79 | 578 | pragma Assert (Nkind (N) = N_Freeze_Entity); |
579 | ||
0577b0b1 | 580 | AC : constant Node_Id := Address_Clause (E); |
581 | Loc : constant Source_Ptr := Sloc (AC); | |
582 | Typ : constant Entity_Id := Etype (E); | |
583 | Aexp : constant Node_Id := Expression (AC); | |
c2b56224 | 584 | |
c2b56224 | 585 | Expr : Node_Id; |
0577b0b1 | 586 | -- Address expression (not necessarily the same as Aexp, for example |
587 | -- when Aexp is a reference to a constant, in which case Expr gets | |
588 | -- reset to reference the value expression of the constant. | |
589 | ||
0577b0b1 | 590 | procedure Compile_Time_Bad_Alignment; |
591 | -- Post error warnings when alignment is known to be incompatible. Note | |
592 | -- that we do not go as far as inserting a raise of Program_Error since | |
593 | -- this is an erroneous case, and it may happen that we are lucky and an | |
d6da7448 | 594 | -- underaligned address turns out to be OK after all. |
0577b0b1 | 595 | |
596 | -------------------------------- | |
597 | -- Compile_Time_Bad_Alignment -- | |
598 | -------------------------------- | |
599 | ||
600 | procedure Compile_Time_Bad_Alignment is | |
601 | begin | |
d6da7448 | 602 | if Address_Clause_Overlay_Warnings then |
0577b0b1 | 603 | Error_Msg_FE |
cb97ae5c | 604 | ("?o?specified address for& may be inconsistent with alignment", |
0577b0b1 | 605 | Aexp, E); |
606 | Error_Msg_FE | |
cb97ae5c | 607 | ("\?o?program execution may be erroneous (RM 13.3(27))", |
0577b0b1 | 608 | Aexp, E); |
83f8f0a6 | 609 | Set_Address_Warning_Posted (AC); |
0577b0b1 | 610 | end if; |
611 | end Compile_Time_Bad_Alignment; | |
c2b56224 | 612 | |
2af58f67 | 613 | -- Start of processing for Apply_Address_Clause_Check |
5c61a0ff | 614 | |
c2b56224 | 615 | begin |
d6da7448 | 616 | -- See if alignment check needed. Note that we never need a check if the |
617 | -- maximum alignment is one, since the check will always succeed. | |
618 | ||
619 | -- Note: we do not check for checks suppressed here, since that check | |
620 | -- was done in Sem_Ch13 when the address clause was processed. We are | |
621 | -- only called if checks were not suppressed. The reason for this is | |
622 | -- that we have to delay the call to Apply_Alignment_Check till freeze | |
623 | -- time (so that all types etc are elaborated), but we have to check | |
624 | -- the status of check suppressing at the point of the address clause. | |
625 | ||
626 | if No (AC) | |
627 | or else not Check_Address_Alignment (AC) | |
628 | or else Maximum_Alignment = 1 | |
629 | then | |
630 | return; | |
631 | end if; | |
632 | ||
633 | -- Obtain expression from address clause | |
9dfe12ae | 634 | |
0577b0b1 | 635 | Expr := Expression (AC); |
636 | ||
637 | -- The following loop digs for the real expression to use in the check | |
638 | ||
639 | loop | |
640 | -- For constant, get constant expression | |
641 | ||
642 | if Is_Entity_Name (Expr) | |
643 | and then Ekind (Entity (Expr)) = E_Constant | |
644 | then | |
645 | Expr := Constant_Value (Entity (Expr)); | |
646 | ||
647 | -- For unchecked conversion, get result to convert | |
648 | ||
649 | elsif Nkind (Expr) = N_Unchecked_Type_Conversion then | |
650 | Expr := Expression (Expr); | |
651 | ||
652 | -- For (common case) of To_Address call, get argument | |
653 | ||
654 | elsif Nkind (Expr) = N_Function_Call | |
655 | and then Is_Entity_Name (Name (Expr)) | |
656 | and then Is_RTE (Entity (Name (Expr)), RE_To_Address) | |
657 | then | |
658 | Expr := First (Parameter_Associations (Expr)); | |
659 | ||
660 | if Nkind (Expr) = N_Parameter_Association then | |
661 | Expr := Explicit_Actual_Parameter (Expr); | |
662 | end if; | |
663 | ||
664 | -- We finally have the real expression | |
665 | ||
666 | else | |
667 | exit; | |
668 | end if; | |
669 | end loop; | |
670 | ||
d6da7448 | 671 | -- See if we know that Expr has a bad alignment at compile time |
c2b56224 | 672 | |
673 | if Compile_Time_Known_Value (Expr) | |
f2a06be9 | 674 | and then (Known_Alignment (E) or else Known_Alignment (Typ)) |
c2b56224 | 675 | then |
f2a06be9 | 676 | declare |
677 | AL : Uint := Alignment (Typ); | |
678 | ||
679 | begin | |
680 | -- The object alignment might be more restrictive than the | |
681 | -- type alignment. | |
682 | ||
683 | if Known_Alignment (E) then | |
684 | AL := Alignment (E); | |
685 | end if; | |
686 | ||
687 | if Expr_Value (Expr) mod AL /= 0 then | |
0577b0b1 | 688 | Compile_Time_Bad_Alignment; |
689 | else | |
690 | return; | |
f2a06be9 | 691 | end if; |
692 | end; | |
c2b56224 | 693 | |
0577b0b1 | 694 | -- If the expression has the form X'Address, then we can find out if |
695 | -- the object X has an alignment that is compatible with the object E. | |
d6da7448 | 696 | -- If it hasn't or we don't know, we defer issuing the warning until |
697 | -- the end of the compilation to take into account back end annotations. | |
c2b56224 | 698 | |
0577b0b1 | 699 | elsif Nkind (Expr) = N_Attribute_Reference |
700 | and then Attribute_Name (Expr) = Name_Address | |
d6da7448 | 701 | and then Has_Compatible_Alignment (E, Prefix (Expr)) = Known_Compatible |
0577b0b1 | 702 | then |
d6da7448 | 703 | return; |
0577b0b1 | 704 | end if; |
c2b56224 | 705 | |
6fb3c314 | 706 | -- Here we do not know if the value is acceptable. Strictly we don't |
707 | -- have to do anything, since if the alignment is bad, we have an | |
708 | -- erroneous program. However we are allowed to check for erroneous | |
709 | -- conditions and we decide to do this by default if the check is not | |
710 | -- suppressed. | |
0577b0b1 | 711 | |
712 | -- However, don't do the check if elaboration code is unwanted | |
713 | ||
714 | if Restriction_Active (No_Elaboration_Code) then | |
715 | return; | |
716 | ||
717 | -- Generate a check to raise PE if alignment may be inappropriate | |
718 | ||
719 | else | |
720 | -- If the original expression is a non-static constant, use the | |
721 | -- name of the constant itself rather than duplicating its | |
00c403ee | 722 | -- defining expression, which was extracted above. |
0577b0b1 | 723 | |
00c403ee | 724 | -- Note: Expr is empty if the address-clause is applied to in-mode |
725 | -- actuals (allowed by 13.1(22)). | |
726 | ||
727 | if not Present (Expr) | |
728 | or else | |
729 | (Is_Entity_Name (Expression (AC)) | |
730 | and then Ekind (Entity (Expression (AC))) = E_Constant | |
731 | and then Nkind (Parent (Entity (Expression (AC)))) | |
732 | = N_Object_Declaration) | |
0577b0b1 | 733 | then |
734 | Expr := New_Copy_Tree (Expression (AC)); | |
735 | else | |
736 | Remove_Side_Effects (Expr); | |
c2b56224 | 737 | end if; |
c2b56224 | 738 | |
d950dc79 | 739 | if No (Actions (N)) then |
740 | Set_Actions (N, New_List); | |
741 | end if; | |
742 | ||
743 | Prepend_To (Actions (N), | |
0577b0b1 | 744 | Make_Raise_Program_Error (Loc, |
745 | Condition => | |
746 | Make_Op_Ne (Loc, | |
747 | Left_Opnd => | |
748 | Make_Op_Mod (Loc, | |
749 | Left_Opnd => | |
750 | Unchecked_Convert_To | |
751 | (RTE (RE_Integer_Address), Expr), | |
752 | Right_Opnd => | |
753 | Make_Attribute_Reference (Loc, | |
d950dc79 | 754 | Prefix => New_Occurrence_Of (E, Loc), |
0577b0b1 | 755 | Attribute_Name => Name_Alignment)), |
756 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
d950dc79 | 757 | Reason => PE_Misaligned_Address_Value)); |
758 | Analyze (First (Actions (N)), Suppress => All_Checks); | |
0577b0b1 | 759 | return; |
760 | end if; | |
9dfe12ae | 761 | |
762 | exception | |
0577b0b1 | 763 | -- If we have some missing run time component in configurable run time |
764 | -- mode then just skip the check (it is not required in any case). | |
765 | ||
9dfe12ae | 766 | when RE_Not_Available => |
767 | return; | |
0577b0b1 | 768 | end Apply_Address_Clause_Check; |
c2b56224 | 769 | |
ee6ba406 | 770 | ------------------------------------- |
771 | -- Apply_Arithmetic_Overflow_Check -- | |
772 | ------------------------------------- | |
773 | ||
3cce7f32 | 774 | procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is |
775 | begin | |
776 | -- Use old routine in almost all cases (the only case we are treating | |
21a55437 | 777 | -- specially is the case of a signed integer arithmetic op with the |
0df9d43f | 778 | -- overflow checking mode set to MINIMIZED or ELIMINATED). |
3cce7f32 | 779 | |
0df9d43f | 780 | if Overflow_Check_Mode = Strict |
3cce7f32 | 781 | or else not Is_Signed_Integer_Arithmetic_Op (N) |
782 | then | |
0df9d43f | 783 | Apply_Arithmetic_Overflow_Strict (N); |
3cce7f32 | 784 | |
21a55437 | 785 | -- Otherwise use the new routine for the case of a signed integer |
786 | -- arithmetic op, with Do_Overflow_Check set to True, and the checking | |
787 | -- mode is MINIMIZED or ELIMINATED. | |
3cce7f32 | 788 | |
789 | else | |
790 | Apply_Arithmetic_Overflow_Minimized_Eliminated (N); | |
791 | end if; | |
792 | end Apply_Arithmetic_Overflow_Check; | |
793 | ||
0df9d43f | 794 | -------------------------------------- |
795 | -- Apply_Arithmetic_Overflow_Strict -- | |
796 | -------------------------------------- | |
3cce7f32 | 797 | |
f40f9731 | 798 | -- This routine is called only if the type is an integer type, and a |
799 | -- software arithmetic overflow check may be needed for op (add, subtract, | |
800 | -- or multiply). This check is performed only if Software_Overflow_Checking | |
801 | -- is enabled and Do_Overflow_Check is set. In this case we expand the | |
802 | -- operation into a more complex sequence of tests that ensures that | |
803 | -- overflow is properly caught. | |
ee6ba406 | 804 | |
0df9d43f | 805 | -- This is used in CHECKED modes. It is identical to the code for this |
806 | -- cases before the big overflow earthquake, thus ensuring that in this | |
807 | -- modes we have compatible behavior (and reliability) to what was there | |
808 | -- before. It is also called for types other than signed integers, and if | |
809 | -- the Do_Overflow_Check flag is off. | |
3cce7f32 | 810 | |
811 | -- Note: we also call this routine if we decide in the MINIMIZED case | |
812 | -- to give up and just generate an overflow check without any fuss. | |
813 | ||
0df9d43f | 814 | procedure Apply_Arithmetic_Overflow_Strict (N : Node_Id) is |
21a55437 | 815 | Loc : constant Source_Ptr := Sloc (N); |
816 | Typ : constant Entity_Id := Etype (N); | |
817 | Rtyp : constant Entity_Id := Root_Type (Typ); | |
ee6ba406 | 818 | |
819 | begin | |
0df9d43f | 820 | -- Nothing to do if Do_Overflow_Check not set or overflow checks |
821 | -- suppressed. | |
822 | ||
823 | if not Do_Overflow_Check (N) then | |
824 | return; | |
825 | end if; | |
826 | ||
f40f9731 | 827 | -- An interesting special case. If the arithmetic operation appears as |
828 | -- the operand of a type conversion: | |
829 | ||
830 | -- type1 (x op y) | |
831 | ||
832 | -- and all the following conditions apply: | |
833 | ||
834 | -- arithmetic operation is for a signed integer type | |
835 | -- target type type1 is a static integer subtype | |
836 | -- range of x and y are both included in the range of type1 | |
837 | -- range of x op y is included in the range of type1 | |
838 | -- size of type1 is at least twice the result size of op | |
839 | ||
840 | -- then we don't do an overflow check in any case, instead we transform | |
841 | -- the operation so that we end up with: | |
842 | ||
843 | -- type1 (type1 (x) op type1 (y)) | |
844 | ||
845 | -- This avoids intermediate overflow before the conversion. It is | |
846 | -- explicitly permitted by RM 3.5.4(24): | |
847 | ||
848 | -- For the execution of a predefined operation of a signed integer | |
849 | -- type, the implementation need not raise Constraint_Error if the | |
850 | -- result is outside the base range of the type, so long as the | |
851 | -- correct result is produced. | |
852 | ||
853 | -- It's hard to imagine that any programmer counts on the exception | |
854 | -- being raised in this case, and in any case it's wrong coding to | |
855 | -- have this expectation, given the RM permission. Furthermore, other | |
856 | -- Ada compilers do allow such out of range results. | |
857 | ||
858 | -- Note that we do this transformation even if overflow checking is | |
859 | -- off, since this is precisely about giving the "right" result and | |
860 | -- avoiding the need for an overflow check. | |
861 | ||
8eb4a5eb | 862 | -- Note: this circuit is partially redundant with respect to the similar |
863 | -- processing in Exp_Ch4.Expand_N_Type_Conversion, but the latter deals | |
864 | -- with cases that do not come through here. We still need the following | |
865 | -- processing even with the Exp_Ch4 code in place, since we want to be | |
866 | -- sure not to generate the arithmetic overflow check in these cases | |
867 | -- (Exp_Ch4 would have a hard time removing them once generated). | |
868 | ||
f40f9731 | 869 | if Is_Signed_Integer_Type (Typ) |
870 | and then Nkind (Parent (N)) = N_Type_Conversion | |
ee6ba406 | 871 | then |
f32c377d | 872 | Conversion_Optimization : declare |
f40f9731 | 873 | Target_Type : constant Entity_Id := |
b6341c67 | 874 | Base_Type (Entity (Subtype_Mark (Parent (N)))); |
f40f9731 | 875 | |
876 | Llo, Lhi : Uint; | |
877 | Rlo, Rhi : Uint; | |
878 | LOK, ROK : Boolean; | |
879 | ||
880 | Vlo : Uint; | |
881 | Vhi : Uint; | |
882 | VOK : Boolean; | |
883 | ||
884 | Tlo : Uint; | |
885 | Thi : Uint; | |
886 | ||
887 | begin | |
888 | if Is_Integer_Type (Target_Type) | |
889 | and then RM_Size (Root_Type (Target_Type)) >= 2 * RM_Size (Rtyp) | |
890 | then | |
891 | Tlo := Expr_Value (Type_Low_Bound (Target_Type)); | |
892 | Thi := Expr_Value (Type_High_Bound (Target_Type)); | |
893 | ||
9c486805 | 894 | Determine_Range |
895 | (Left_Opnd (N), LOK, Llo, Lhi, Assume_Valid => True); | |
896 | Determine_Range | |
897 | (Right_Opnd (N), ROK, Rlo, Rhi, Assume_Valid => True); | |
f40f9731 | 898 | |
899 | if (LOK and ROK) | |
900 | and then Tlo <= Llo and then Lhi <= Thi | |
901 | and then Tlo <= Rlo and then Rhi <= Thi | |
902 | then | |
9c486805 | 903 | Determine_Range (N, VOK, Vlo, Vhi, Assume_Valid => True); |
f40f9731 | 904 | |
905 | if VOK and then Tlo <= Vlo and then Vhi <= Thi then | |
906 | Rewrite (Left_Opnd (N), | |
907 | Make_Type_Conversion (Loc, | |
908 | Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), | |
909 | Expression => Relocate_Node (Left_Opnd (N)))); | |
910 | ||
911 | Rewrite (Right_Opnd (N), | |
912 | Make_Type_Conversion (Loc, | |
913 | Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), | |
914 | Expression => Relocate_Node (Right_Opnd (N)))); | |
915 | ||
780bfb21 | 916 | -- Rewrite the conversion operand so that the original |
917 | -- node is retained, in order to avoid the warning for | |
918 | -- redundant conversions in Resolve_Type_Conversion. | |
919 | ||
920 | Rewrite (N, Relocate_Node (N)); | |
921 | ||
f40f9731 | 922 | Set_Etype (N, Target_Type); |
780bfb21 | 923 | |
f40f9731 | 924 | Analyze_And_Resolve (Left_Opnd (N), Target_Type); |
925 | Analyze_And_Resolve (Right_Opnd (N), Target_Type); | |
926 | ||
927 | -- Given that the target type is twice the size of the | |
928 | -- source type, overflow is now impossible, so we can | |
929 | -- safely kill the overflow check and return. | |
930 | ||
931 | Set_Do_Overflow_Check (N, False); | |
932 | return; | |
933 | end if; | |
934 | end if; | |
935 | end if; | |
f32c377d | 936 | end Conversion_Optimization; |
ee6ba406 | 937 | end if; |
938 | ||
f40f9731 | 939 | -- Now see if an overflow check is required |
940 | ||
941 | declare | |
942 | Siz : constant Int := UI_To_Int (Esize (Rtyp)); | |
943 | Dsiz : constant Int := Siz * 2; | |
944 | Opnod : Node_Id; | |
945 | Ctyp : Entity_Id; | |
946 | Opnd : Node_Id; | |
947 | Cent : RE_Id; | |
ee6ba406 | 948 | |
f40f9731 | 949 | begin |
950 | -- Skip check if back end does overflow checks, or the overflow flag | |
df40eeb0 | 951 | -- is not set anyway, or we are not doing code expansion, or the |
952 | -- parent node is a type conversion whose operand is an arithmetic | |
953 | -- operation on signed integers on which the expander can promote | |
bbbed24b | 954 | -- later the operands to type Integer (see Expand_N_Type_Conversion). |
ee6ba406 | 955 | |
f40f9731 | 956 | -- Special case CLI target, where arithmetic overflow checks can be |
957 | -- performed for integer and long_integer | |
ee6ba406 | 958 | |
f40f9731 | 959 | if Backend_Overflow_Checks_On_Target |
960 | or else not Do_Overflow_Check (N) | |
6dbcfcd9 | 961 | or else not Full_Expander_Active |
df40eeb0 | 962 | or else (Present (Parent (N)) |
963 | and then Nkind (Parent (N)) = N_Type_Conversion | |
964 | and then Integer_Promotion_Possible (Parent (N))) | |
f40f9731 | 965 | or else |
966 | (VM_Target = CLI_Target and then Siz >= Standard_Integer_Size) | |
967 | then | |
968 | return; | |
969 | end if; | |
ee6ba406 | 970 | |
f40f9731 | 971 | -- Otherwise, generate the full general code for front end overflow |
972 | -- detection, which works by doing arithmetic in a larger type: | |
ee6ba406 | 973 | |
f40f9731 | 974 | -- x op y |
ee6ba406 | 975 | |
f40f9731 | 976 | -- is expanded into |
ee6ba406 | 977 | |
f40f9731 | 978 | -- Typ (Checktyp (x) op Checktyp (y)); |
ee6ba406 | 979 | |
f40f9731 | 980 | -- where Typ is the type of the original expression, and Checktyp is |
981 | -- an integer type of sufficient length to hold the largest possible | |
982 | -- result. | |
ee6ba406 | 983 | |
f40f9731 | 984 | -- If the size of check type exceeds the size of Long_Long_Integer, |
985 | -- we use a different approach, expanding to: | |
ee6ba406 | 986 | |
f40f9731 | 987 | -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y))) |
ee6ba406 | 988 | |
f40f9731 | 989 | -- where xxx is Add, Multiply or Subtract as appropriate |
ee6ba406 | 990 | |
f40f9731 | 991 | -- Find check type if one exists |
992 | ||
993 | if Dsiz <= Standard_Integer_Size then | |
994 | Ctyp := Standard_Integer; | |
ee6ba406 | 995 | |
f40f9731 | 996 | elsif Dsiz <= Standard_Long_Long_Integer_Size then |
997 | Ctyp := Standard_Long_Long_Integer; | |
998 | ||
999 | -- No check type exists, use runtime call | |
ee6ba406 | 1000 | |
1001 | else | |
f40f9731 | 1002 | if Nkind (N) = N_Op_Add then |
1003 | Cent := RE_Add_With_Ovflo_Check; | |
ee6ba406 | 1004 | |
f40f9731 | 1005 | elsif Nkind (N) = N_Op_Multiply then |
1006 | Cent := RE_Multiply_With_Ovflo_Check; | |
ee6ba406 | 1007 | |
f40f9731 | 1008 | else |
1009 | pragma Assert (Nkind (N) = N_Op_Subtract); | |
1010 | Cent := RE_Subtract_With_Ovflo_Check; | |
1011 | end if; | |
1012 | ||
1013 | Rewrite (N, | |
1014 | OK_Convert_To (Typ, | |
1015 | Make_Function_Call (Loc, | |
1016 | Name => New_Reference_To (RTE (Cent), Loc), | |
1017 | Parameter_Associations => New_List ( | |
1018 | OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)), | |
1019 | OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N)))))); | |
ee6ba406 | 1020 | |
f40f9731 | 1021 | Analyze_And_Resolve (N, Typ); |
1022 | return; | |
1023 | end if; | |
ee6ba406 | 1024 | |
f40f9731 | 1025 | -- If we fall through, we have the case where we do the arithmetic |
1026 | -- in the next higher type and get the check by conversion. In these | |
1027 | -- cases Ctyp is set to the type to be used as the check type. | |
ee6ba406 | 1028 | |
f40f9731 | 1029 | Opnod := Relocate_Node (N); |
ee6ba406 | 1030 | |
f40f9731 | 1031 | Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod)); |
ee6ba406 | 1032 | |
f40f9731 | 1033 | Analyze (Opnd); |
1034 | Set_Etype (Opnd, Ctyp); | |
1035 | Set_Analyzed (Opnd, True); | |
1036 | Set_Left_Opnd (Opnod, Opnd); | |
ee6ba406 | 1037 | |
f40f9731 | 1038 | Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod)); |
ee6ba406 | 1039 | |
f40f9731 | 1040 | Analyze (Opnd); |
1041 | Set_Etype (Opnd, Ctyp); | |
1042 | Set_Analyzed (Opnd, True); | |
1043 | Set_Right_Opnd (Opnod, Opnd); | |
ee6ba406 | 1044 | |
f40f9731 | 1045 | -- The type of the operation changes to the base type of the check |
1046 | -- type, and we reset the overflow check indication, since clearly no | |
1047 | -- overflow is possible now that we are using a double length type. | |
1048 | -- We also set the Analyzed flag to avoid a recursive attempt to | |
1049 | -- expand the node. | |
ee6ba406 | 1050 | |
f40f9731 | 1051 | Set_Etype (Opnod, Base_Type (Ctyp)); |
1052 | Set_Do_Overflow_Check (Opnod, False); | |
1053 | Set_Analyzed (Opnod, True); | |
ee6ba406 | 1054 | |
f40f9731 | 1055 | -- Now build the outer conversion |
ee6ba406 | 1056 | |
f40f9731 | 1057 | Opnd := OK_Convert_To (Typ, Opnod); |
1058 | Analyze (Opnd); | |
1059 | Set_Etype (Opnd, Typ); | |
9dfe12ae | 1060 | |
f40f9731 | 1061 | -- In the discrete type case, we directly generate the range check |
1062 | -- for the outer operand. This range check will implement the | |
1063 | -- required overflow check. | |
9dfe12ae | 1064 | |
f40f9731 | 1065 | if Is_Discrete_Type (Typ) then |
1066 | Rewrite (N, Opnd); | |
1067 | Generate_Range_Check | |
1068 | (Expression (N), Typ, CE_Overflow_Check_Failed); | |
9dfe12ae | 1069 | |
f40f9731 | 1070 | -- For other types, we enable overflow checking on the conversion, |
1071 | -- after setting the node as analyzed to prevent recursive attempts | |
1072 | -- to expand the conversion node. | |
9dfe12ae | 1073 | |
f40f9731 | 1074 | else |
1075 | Set_Analyzed (Opnd, True); | |
1076 | Enable_Overflow_Check (Opnd); | |
1077 | Rewrite (N, Opnd); | |
1078 | end if; | |
1079 | ||
1080 | exception | |
1081 | when RE_Not_Available => | |
1082 | return; | |
1083 | end; | |
0df9d43f | 1084 | end Apply_Arithmetic_Overflow_Strict; |
3cce7f32 | 1085 | |
1086 | ---------------------------------------------------- | |
1087 | -- Apply_Arithmetic_Overflow_Minimized_Eliminated -- | |
1088 | ---------------------------------------------------- | |
1089 | ||
1090 | procedure Apply_Arithmetic_Overflow_Minimized_Eliminated (Op : Node_Id) is | |
1091 | pragma Assert (Is_Signed_Integer_Arithmetic_Op (Op)); | |
3cce7f32 | 1092 | |
1093 | Loc : constant Source_Ptr := Sloc (Op); | |
1094 | P : constant Node_Id := Parent (Op); | |
1095 | ||
49b3a812 | 1096 | LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); |
1097 | -- Operands and results are of this type when we convert | |
1098 | ||
3cce7f32 | 1099 | Result_Type : constant Entity_Id := Etype (Op); |
1100 | -- Original result type | |
1101 | ||
db415383 | 1102 | Check_Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
3cce7f32 | 1103 | pragma Assert (Check_Mode in Minimized_Or_Eliminated); |
1104 | ||
1105 | Lo, Hi : Uint; | |
1106 | -- Ranges of values for result | |
1107 | ||
1108 | begin | |
1109 | -- Nothing to do if our parent is one of the following: | |
1110 | ||
0326b4d4 | 1111 | -- Another signed integer arithmetic op |
3cce7f32 | 1112 | -- A membership operation |
1113 | -- A comparison operation | |
1114 | ||
1115 | -- In all these cases, we will process at the higher level (and then | |
1116 | -- this node will be processed during the downwards recursion that | |
0df9d43f | 1117 | -- is part of the processing in Minimize_Eliminate_Overflows). |
3cce7f32 | 1118 | |
1119 | if Is_Signed_Integer_Arithmetic_Op (P) | |
b8a17a21 | 1120 | or else Nkind (P) in N_Membership_Test |
1121 | or else Nkind (P) in N_Op_Compare | |
aa4b16cb | 1122 | |
70a2dff4 | 1123 | -- This is also true for an alternative in a case expression |
1124 | ||
1125 | or else Nkind (P) = N_Case_Expression_Alternative | |
1126 | ||
1127 | -- This is also true for a range operand in a membership test | |
aa4b16cb | 1128 | |
b8a17a21 | 1129 | or else (Nkind (P) = N_Range |
1130 | and then Nkind (Parent (P)) in N_Membership_Test) | |
3cce7f32 | 1131 | then |
1132 | return; | |
1133 | end if; | |
1134 | ||
0326b4d4 | 1135 | -- Otherwise, we have a top level arithmetic operation node, and this |
21a55437 | 1136 | -- is where we commence the special processing for MINIMIZED/ELIMINATED |
1137 | -- modes. This is the case where we tell the machinery not to move into | |
1138 | -- Bignum mode at this top level (of course the top level operation | |
1139 | -- will still be in Bignum mode if either of its operands are of type | |
1140 | -- Bignum). | |
3cce7f32 | 1141 | |
0df9d43f | 1142 | Minimize_Eliminate_Overflows (Op, Lo, Hi, Top_Level => True); |
3cce7f32 | 1143 | |
1144 | -- That call may but does not necessarily change the result type of Op. | |
1145 | -- It is the job of this routine to undo such changes, so that at the | |
1146 | -- top level, we have the proper type. This "undoing" is a point at | |
1147 | -- which a final overflow check may be applied. | |
1148 | ||
f32c377d | 1149 | -- If the result type was not fiddled we are all set. We go to base |
1150 | -- types here because things may have been rewritten to generate the | |
1151 | -- base type of the operand types. | |
3cce7f32 | 1152 | |
f32c377d | 1153 | if Base_Type (Etype (Op)) = Base_Type (Result_Type) then |
3cce7f32 | 1154 | return; |
1155 | ||
1156 | -- Bignum case | |
1157 | ||
49b3a812 | 1158 | elsif Is_RTE (Etype (Op), RE_Bignum) then |
3cce7f32 | 1159 | |
d94b5da2 | 1160 | -- We need a sequence that looks like: |
3cce7f32 | 1161 | |
1162 | -- Rnn : Result_Type; | |
1163 | ||
1164 | -- declare | |
d94b5da2 | 1165 | -- M : Mark_Id := SS_Mark; |
3cce7f32 | 1166 | -- begin |
49b3a812 | 1167 | -- Rnn := Long_Long_Integer'Base (From_Bignum (Op)); |
3cce7f32 | 1168 | -- SS_Release (M); |
1169 | -- end; | |
1170 | ||
1171 | -- This block is inserted (using Insert_Actions), and then the node | |
1172 | -- is replaced with a reference to Rnn. | |
1173 | ||
1174 | -- A special case arises if our parent is a conversion node. In this | |
1175 | -- case no point in generating a conversion to Result_Type, we will | |
1176 | -- let the parent handle this. Note that this special case is not | |
1177 | -- just about optimization. Consider | |
1178 | ||
1179 | -- A,B,C : Integer; | |
1180 | -- ... | |
49b3a812 | 1181 | -- X := Long_Long_Integer'Base (A * (B ** C)); |
3cce7f32 | 1182 | |
1183 | -- Now the product may fit in Long_Long_Integer but not in Integer. | |
21a55437 | 1184 | -- In MINIMIZED/ELIMINATED mode, we don't want to introduce an |
1185 | -- overflow exception for this intermediate value. | |
3cce7f32 | 1186 | |
1187 | declare | |
49b3a812 | 1188 | Blk : constant Node_Id := Make_Bignum_Block (Loc); |
3cce7f32 | 1189 | Rnn : constant Entity_Id := Make_Temporary (Loc, 'R', Op); |
1190 | RHS : Node_Id; | |
1191 | ||
1192 | Rtype : Entity_Id; | |
1193 | ||
1194 | begin | |
1195 | RHS := Convert_From_Bignum (Op); | |
1196 | ||
1197 | if Nkind (P) /= N_Type_Conversion then | |
49b3a812 | 1198 | Convert_To_And_Rewrite (Result_Type, RHS); |
3cce7f32 | 1199 | Rtype := Result_Type; |
1200 | ||
1201 | -- Interesting question, do we need a check on that conversion | |
1202 | -- operation. Answer, not if we know the result is in range. | |
1203 | -- At the moment we are not taking advantage of this. To be | |
1204 | -- looked at later ??? | |
1205 | ||
1206 | else | |
49b3a812 | 1207 | Rtype := LLIB; |
3cce7f32 | 1208 | end if; |
1209 | ||
1210 | Insert_Before | |
1211 | (First (Statements (Handled_Statement_Sequence (Blk))), | |
1212 | Make_Assignment_Statement (Loc, | |
1213 | Name => New_Occurrence_Of (Rnn, Loc), | |
1214 | Expression => RHS)); | |
1215 | ||
1216 | Insert_Actions (Op, New_List ( | |
1217 | Make_Object_Declaration (Loc, | |
1218 | Defining_Identifier => Rnn, | |
1219 | Object_Definition => New_Occurrence_Of (Rtype, Loc)), | |
1220 | Blk)); | |
1221 | ||
1222 | Rewrite (Op, New_Occurrence_Of (Rnn, Loc)); | |
1223 | Analyze_And_Resolve (Op); | |
1224 | end; | |
1225 | ||
412f75eb | 1226 | -- Here we know the result is Long_Long_Integer'Base, of that it has |
1227 | -- been rewritten because the parent operation is a conversion. See | |
0df9d43f | 1228 | -- Apply_Arithmetic_Overflow_Strict.Conversion_Optimization. |
3cce7f32 | 1229 | |
1230 | else | |
f32c377d | 1231 | pragma Assert |
1232 | (Etype (Op) = LLIB or else Nkind (Parent (Op)) = N_Type_Conversion); | |
3cce7f32 | 1233 | |
1234 | -- All we need to do here is to convert the result to the proper | |
1235 | -- result type. As explained above for the Bignum case, we can | |
1236 | -- omit this if our parent is a type conversion. | |
1237 | ||
1238 | if Nkind (P) /= N_Type_Conversion then | |
1239 | Convert_To_And_Rewrite (Result_Type, Op); | |
1240 | end if; | |
1241 | ||
1242 | Analyze_And_Resolve (Op); | |
1243 | end if; | |
1244 | end Apply_Arithmetic_Overflow_Minimized_Eliminated; | |
ee6ba406 | 1245 | |
ee6ba406 | 1246 | ---------------------------- |
1247 | -- Apply_Constraint_Check -- | |
1248 | ---------------------------- | |
1249 | ||
1250 | procedure Apply_Constraint_Check | |
1251 | (N : Node_Id; | |
1252 | Typ : Entity_Id; | |
1253 | No_Sliding : Boolean := False) | |
1254 | is | |
1255 | Desig_Typ : Entity_Id; | |
1256 | ||
1257 | begin | |
7aafae1c | 1258 | -- No checks inside a generic (check the instantiations) |
1259 | ||
ee6ba406 | 1260 | if Inside_A_Generic then |
1261 | return; | |
7aafae1c | 1262 | end if; |
ee6ba406 | 1263 | |
6fb3c314 | 1264 | -- Apply required constraint checks |
7aafae1c | 1265 | |
1266 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 1267 | Apply_Scalar_Range_Check (N, Typ); |
1268 | ||
1269 | elsif Is_Array_Type (Typ) then | |
1270 | ||
05fcfafb | 1271 | -- A useful optimization: an aggregate with only an others clause |
5f260d20 | 1272 | -- always has the right bounds. |
1273 | ||
1274 | if Nkind (N) = N_Aggregate | |
1275 | and then No (Expressions (N)) | |
1276 | and then Nkind | |
1277 | (First (Choices (First (Component_Associations (N))))) | |
1278 | = N_Others_Choice | |
1279 | then | |
1280 | return; | |
1281 | end if; | |
1282 | ||
ee6ba406 | 1283 | if Is_Constrained (Typ) then |
1284 | Apply_Length_Check (N, Typ); | |
1285 | ||
1286 | if No_Sliding then | |
1287 | Apply_Range_Check (N, Typ); | |
1288 | end if; | |
1289 | else | |
1290 | Apply_Range_Check (N, Typ); | |
1291 | end if; | |
1292 | ||
4fb5f0a0 | 1293 | elsif (Is_Record_Type (Typ) or else Is_Private_Type (Typ)) |
ee6ba406 | 1294 | and then Has_Discriminants (Base_Type (Typ)) |
1295 | and then Is_Constrained (Typ) | |
1296 | then | |
1297 | Apply_Discriminant_Check (N, Typ); | |
1298 | ||
1299 | elsif Is_Access_Type (Typ) then | |
1300 | ||
1301 | Desig_Typ := Designated_Type (Typ); | |
1302 | ||
1303 | -- No checks necessary if expression statically null | |
1304 | ||
2af58f67 | 1305 | if Known_Null (N) then |
00c403ee | 1306 | if Can_Never_Be_Null (Typ) then |
1307 | Install_Null_Excluding_Check (N); | |
1308 | end if; | |
ee6ba406 | 1309 | |
1310 | -- No sliding possible on access to arrays | |
1311 | ||
1312 | elsif Is_Array_Type (Desig_Typ) then | |
1313 | if Is_Constrained (Desig_Typ) then | |
1314 | Apply_Length_Check (N, Typ); | |
1315 | end if; | |
1316 | ||
1317 | Apply_Range_Check (N, Typ); | |
1318 | ||
1319 | elsif Has_Discriminants (Base_Type (Desig_Typ)) | |
1320 | and then Is_Constrained (Desig_Typ) | |
1321 | then | |
1322 | Apply_Discriminant_Check (N, Typ); | |
1323 | end if; | |
fa7497e8 | 1324 | |
bf3e1520 | 1325 | -- Apply the 2005 Null_Excluding check. Note that we do not apply |
00c403ee | 1326 | -- this check if the constraint node is illegal, as shown by having |
1327 | -- an error posted. This additional guard prevents cascaded errors | |
1328 | -- and compiler aborts on illegal programs involving Ada 2005 checks. | |
1329 | ||
fa7497e8 | 1330 | if Can_Never_Be_Null (Typ) |
1331 | and then not Can_Never_Be_Null (Etype (N)) | |
00c403ee | 1332 | and then not Error_Posted (N) |
fa7497e8 | 1333 | then |
1334 | Install_Null_Excluding_Check (N); | |
1335 | end if; | |
ee6ba406 | 1336 | end if; |
1337 | end Apply_Constraint_Check; | |
1338 | ||
1339 | ------------------------------ | |
1340 | -- Apply_Discriminant_Check -- | |
1341 | ------------------------------ | |
1342 | ||
1343 | procedure Apply_Discriminant_Check | |
1344 | (N : Node_Id; | |
1345 | Typ : Entity_Id; | |
1346 | Lhs : Node_Id := Empty) | |
1347 | is | |
1348 | Loc : constant Source_Ptr := Sloc (N); | |
1349 | Do_Access : constant Boolean := Is_Access_Type (Typ); | |
1350 | S_Typ : Entity_Id := Etype (N); | |
1351 | Cond : Node_Id; | |
1352 | T_Typ : Entity_Id; | |
1353 | ||
7be5088a | 1354 | function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean; |
1355 | -- A heap object with an indefinite subtype is constrained by its | |
1356 | -- initial value, and assigning to it requires a constraint_check. | |
1357 | -- The target may be an explicit dereference, or a renaming of one. | |
1358 | ||
ee6ba406 | 1359 | function Is_Aliased_Unconstrained_Component return Boolean; |
1360 | -- It is possible for an aliased component to have a nominal | |
1361 | -- unconstrained subtype (through instantiation). If this is a | |
1362 | -- discriminated component assigned in the expansion of an aggregate | |
1363 | -- in an initialization, the check must be suppressed. This unusual | |
2af58f67 | 1364 | -- situation requires a predicate of its own. |
ee6ba406 | 1365 | |
7be5088a | 1366 | ---------------------------------- |
1367 | -- Denotes_Explicit_Dereference -- | |
1368 | ---------------------------------- | |
1369 | ||
1370 | function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean is | |
1371 | begin | |
1372 | return | |
1373 | Nkind (Obj) = N_Explicit_Dereference | |
1374 | or else | |
1375 | (Is_Entity_Name (Obj) | |
1376 | and then Present (Renamed_Object (Entity (Obj))) | |
9474aa9c | 1377 | and then Nkind (Renamed_Object (Entity (Obj))) = |
1378 | N_Explicit_Dereference); | |
7be5088a | 1379 | end Denotes_Explicit_Dereference; |
1380 | ||
ee6ba406 | 1381 | ---------------------------------------- |
1382 | -- Is_Aliased_Unconstrained_Component -- | |
1383 | ---------------------------------------- | |
1384 | ||
1385 | function Is_Aliased_Unconstrained_Component return Boolean is | |
1386 | Comp : Entity_Id; | |
1387 | Pref : Node_Id; | |
1388 | ||
1389 | begin | |
1390 | if Nkind (Lhs) /= N_Selected_Component then | |
1391 | return False; | |
1392 | else | |
1393 | Comp := Entity (Selector_Name (Lhs)); | |
1394 | Pref := Prefix (Lhs); | |
1395 | end if; | |
1396 | ||
1397 | if Ekind (Comp) /= E_Component | |
1398 | or else not Is_Aliased (Comp) | |
1399 | then | |
1400 | return False; | |
1401 | end if; | |
1402 | ||
1403 | return not Comes_From_Source (Pref) | |
1404 | and then In_Instance | |
1405 | and then not Is_Constrained (Etype (Comp)); | |
1406 | end Is_Aliased_Unconstrained_Component; | |
1407 | ||
1408 | -- Start of processing for Apply_Discriminant_Check | |
1409 | ||
1410 | begin | |
1411 | if Do_Access then | |
1412 | T_Typ := Designated_Type (Typ); | |
1413 | else | |
1414 | T_Typ := Typ; | |
1415 | end if; | |
1416 | ||
1417 | -- Nothing to do if discriminant checks are suppressed or else no code | |
1418 | -- is to be generated | |
1419 | ||
6dbcfcd9 | 1420 | if not Full_Expander_Active |
ee6ba406 | 1421 | or else Discriminant_Checks_Suppressed (T_Typ) |
1422 | then | |
1423 | return; | |
1424 | end if; | |
1425 | ||
feff2f05 | 1426 | -- No discriminant checks necessary for an access when expression is |
1427 | -- statically Null. This is not only an optimization, it is fundamental | |
1428 | -- because otherwise discriminant checks may be generated in init procs | |
1429 | -- for types containing an access to a not-yet-frozen record, causing a | |
1430 | -- deadly forward reference. | |
ee6ba406 | 1431 | |
feff2f05 | 1432 | -- Also, if the expression is of an access type whose designated type is |
1433 | -- incomplete, then the access value must be null and we suppress the | |
1434 | -- check. | |
ee6ba406 | 1435 | |
2af58f67 | 1436 | if Known_Null (N) then |
ee6ba406 | 1437 | return; |
1438 | ||
1439 | elsif Is_Access_Type (S_Typ) then | |
1440 | S_Typ := Designated_Type (S_Typ); | |
1441 | ||
1442 | if Ekind (S_Typ) = E_Incomplete_Type then | |
1443 | return; | |
1444 | end if; | |
1445 | end if; | |
1446 | ||
0577b0b1 | 1447 | -- If an assignment target is present, then we need to generate the |
1448 | -- actual subtype if the target is a parameter or aliased object with | |
1449 | -- an unconstrained nominal subtype. | |
1450 | ||
1451 | -- Ada 2005 (AI-363): For Ada 2005, we limit the building of the actual | |
1452 | -- subtype to the parameter and dereference cases, since other aliased | |
1453 | -- objects are unconstrained (unless the nominal subtype is explicitly | |
7be5088a | 1454 | -- constrained). |
ee6ba406 | 1455 | |
1456 | if Present (Lhs) | |
1457 | and then (Present (Param_Entity (Lhs)) | |
de54c5ab | 1458 | or else (Ada_Version < Ada_2005 |
0577b0b1 | 1459 | and then not Is_Constrained (T_Typ) |
ee6ba406 | 1460 | and then Is_Aliased_View (Lhs) |
0577b0b1 | 1461 | and then not Is_Aliased_Unconstrained_Component) |
de54c5ab | 1462 | or else (Ada_Version >= Ada_2005 |
0577b0b1 | 1463 | and then not Is_Constrained (T_Typ) |
7be5088a | 1464 | and then Denotes_Explicit_Dereference (Lhs) |
0577b0b1 | 1465 | and then Nkind (Original_Node (Lhs)) /= |
1466 | N_Function_Call)) | |
ee6ba406 | 1467 | then |
1468 | T_Typ := Get_Actual_Subtype (Lhs); | |
1469 | end if; | |
1470 | ||
feff2f05 | 1471 | -- Nothing to do if the type is unconstrained (this is the case where |
1472 | -- the actual subtype in the RM sense of N is unconstrained and no check | |
1473 | -- is required). | |
ee6ba406 | 1474 | |
1475 | if not Is_Constrained (T_Typ) then | |
1476 | return; | |
05fcfafb | 1477 | |
1478 | -- Ada 2005: nothing to do if the type is one for which there is a | |
1479 | -- partial view that is constrained. | |
1480 | ||
de54c5ab | 1481 | elsif Ada_Version >= Ada_2005 |
d41a3f41 | 1482 | and then Effectively_Has_Constrained_Partial_View |
1483 | (Typ => Base_Type (T_Typ), | |
1484 | Scop => Current_Scope) | |
05fcfafb | 1485 | then |
1486 | return; | |
ee6ba406 | 1487 | end if; |
1488 | ||
00f91aef | 1489 | -- Nothing to do if the type is an Unchecked_Union |
1490 | ||
1491 | if Is_Unchecked_Union (Base_Type (T_Typ)) then | |
1492 | return; | |
1493 | end if; | |
1494 | ||
feff2f05 | 1495 | -- Suppress checks if the subtypes are the same. the check must be |
1496 | -- preserved in an assignment to a formal, because the constraint is | |
1497 | -- given by the actual. | |
ee6ba406 | 1498 | |
1499 | if Nkind (Original_Node (N)) /= N_Allocator | |
1500 | and then (No (Lhs) | |
1501 | or else not Is_Entity_Name (Lhs) | |
9dfe12ae | 1502 | or else No (Param_Entity (Lhs))) |
ee6ba406 | 1503 | then |
1504 | if (Etype (N) = Typ | |
1505 | or else (Do_Access and then Designated_Type (Typ) = S_Typ)) | |
1506 | and then not Is_Aliased_View (Lhs) | |
1507 | then | |
1508 | return; | |
1509 | end if; | |
1510 | ||
feff2f05 | 1511 | -- We can also eliminate checks on allocators with a subtype mark that |
1512 | -- coincides with the context type. The context type may be a subtype | |
1513 | -- without a constraint (common case, a generic actual). | |
ee6ba406 | 1514 | |
1515 | elsif Nkind (Original_Node (N)) = N_Allocator | |
1516 | and then Is_Entity_Name (Expression (Original_Node (N))) | |
1517 | then | |
1518 | declare | |
9dfe12ae | 1519 | Alloc_Typ : constant Entity_Id := |
b6341c67 | 1520 | Entity (Expression (Original_Node (N))); |
ee6ba406 | 1521 | |
1522 | begin | |
1523 | if Alloc_Typ = T_Typ | |
1524 | or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration | |
1525 | and then Is_Entity_Name ( | |
1526 | Subtype_Indication (Parent (T_Typ))) | |
1527 | and then Alloc_Typ = Base_Type (T_Typ)) | |
1528 | ||
1529 | then | |
1530 | return; | |
1531 | end if; | |
1532 | end; | |
1533 | end if; | |
1534 | ||
feff2f05 | 1535 | -- See if we have a case where the types are both constrained, and all |
1536 | -- the constraints are constants. In this case, we can do the check | |
1537 | -- successfully at compile time. | |
ee6ba406 | 1538 | |
d7ec9a29 | 1539 | -- We skip this check for the case where the node is rewritten`as |
1540 | -- an allocator, because it already carries the context subtype, | |
1541 | -- and extracting the discriminants from the aggregate is messy. | |
ee6ba406 | 1542 | |
1543 | if Is_Constrained (S_Typ) | |
1544 | and then Nkind (Original_Node (N)) /= N_Allocator | |
1545 | then | |
1546 | declare | |
1547 | DconT : Elmt_Id; | |
1548 | Discr : Entity_Id; | |
1549 | DconS : Elmt_Id; | |
1550 | ItemS : Node_Id; | |
1551 | ItemT : Node_Id; | |
1552 | ||
1553 | begin | |
1554 | -- S_Typ may not have discriminants in the case where it is a | |
feff2f05 | 1555 | -- private type completed by a default discriminated type. In that |
1556 | -- case, we need to get the constraints from the underlying_type. | |
1557 | -- If the underlying type is unconstrained (i.e. has no default | |
1558 | -- discriminants) no check is needed. | |
ee6ba406 | 1559 | |
1560 | if Has_Discriminants (S_Typ) then | |
1561 | Discr := First_Discriminant (S_Typ); | |
1562 | DconS := First_Elmt (Discriminant_Constraint (S_Typ)); | |
1563 | ||
1564 | else | |
1565 | Discr := First_Discriminant (Underlying_Type (S_Typ)); | |
1566 | DconS := | |
1567 | First_Elmt | |
1568 | (Discriminant_Constraint (Underlying_Type (S_Typ))); | |
1569 | ||
1570 | if No (DconS) then | |
1571 | return; | |
1572 | end if; | |
fccb5da7 | 1573 | |
1574 | -- A further optimization: if T_Typ is derived from S_Typ | |
1575 | -- without imposing a constraint, no check is needed. | |
1576 | ||
1577 | if Nkind (Original_Node (Parent (T_Typ))) = | |
1578 | N_Full_Type_Declaration | |
1579 | then | |
1580 | declare | |
5c61a0ff | 1581 | Type_Def : constant Node_Id := |
b6341c67 | 1582 | Type_Definition (Original_Node (Parent (T_Typ))); |
fccb5da7 | 1583 | begin |
1584 | if Nkind (Type_Def) = N_Derived_Type_Definition | |
1585 | and then Is_Entity_Name (Subtype_Indication (Type_Def)) | |
1586 | and then Entity (Subtype_Indication (Type_Def)) = S_Typ | |
1587 | then | |
1588 | return; | |
1589 | end if; | |
1590 | end; | |
1591 | end if; | |
ee6ba406 | 1592 | end if; |
1593 | ||
86594966 | 1594 | -- Constraint may appear in full view of type |
1595 | ||
1596 | if Ekind (T_Typ) = E_Private_Subtype | |
1597 | and then Present (Full_View (T_Typ)) | |
1598 | then | |
d7ec9a29 | 1599 | DconT := |
86594966 | 1600 | First_Elmt (Discriminant_Constraint (Full_View (T_Typ))); |
86594966 | 1601 | else |
d7ec9a29 | 1602 | DconT := |
1603 | First_Elmt (Discriminant_Constraint (T_Typ)); | |
86594966 | 1604 | end if; |
ee6ba406 | 1605 | |
1606 | while Present (Discr) loop | |
1607 | ItemS := Node (DconS); | |
1608 | ItemT := Node (DconT); | |
1609 | ||
00c403ee | 1610 | -- For a discriminated component type constrained by the |
1611 | -- current instance of an enclosing type, there is no | |
1612 | -- applicable discriminant check. | |
1613 | ||
1614 | if Nkind (ItemT) = N_Attribute_Reference | |
1615 | and then Is_Access_Type (Etype (ItemT)) | |
1616 | and then Is_Entity_Name (Prefix (ItemT)) | |
1617 | and then Is_Type (Entity (Prefix (ItemT))) | |
1618 | then | |
1619 | return; | |
1620 | end if; | |
1621 | ||
cc60bd16 | 1622 | -- If the expressions for the discriminants are identical |
1623 | -- and it is side-effect free (for now just an entity), | |
1624 | -- this may be a shared constraint, e.g. from a subtype | |
1625 | -- without a constraint introduced as a generic actual. | |
1626 | -- Examine other discriminants if any. | |
1627 | ||
1628 | if ItemS = ItemT | |
1629 | and then Is_Entity_Name (ItemS) | |
1630 | then | |
1631 | null; | |
1632 | ||
1633 | elsif not Is_OK_Static_Expression (ItemS) | |
1634 | or else not Is_OK_Static_Expression (ItemT) | |
1635 | then | |
1636 | exit; | |
ee6ba406 | 1637 | |
cc60bd16 | 1638 | elsif Expr_Value (ItemS) /= Expr_Value (ItemT) then |
ee6ba406 | 1639 | if Do_Access then -- needs run-time check. |
1640 | exit; | |
1641 | else | |
1642 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 1643 | (N, "incorrect value for discriminant&??", |
f15731c4 | 1644 | CE_Discriminant_Check_Failed, Ent => Discr); |
ee6ba406 | 1645 | return; |
1646 | end if; | |
1647 | end if; | |
1648 | ||
1649 | Next_Elmt (DconS); | |
1650 | Next_Elmt (DconT); | |
1651 | Next_Discriminant (Discr); | |
1652 | end loop; | |
1653 | ||
1654 | if No (Discr) then | |
1655 | return; | |
1656 | end if; | |
1657 | end; | |
1658 | end if; | |
1659 | ||
1660 | -- Here we need a discriminant check. First build the expression | |
1661 | -- for the comparisons of the discriminants: | |
1662 | ||
1663 | -- (n.disc1 /= typ.disc1) or else | |
1664 | -- (n.disc2 /= typ.disc2) or else | |
1665 | -- ... | |
1666 | -- (n.discn /= typ.discn) | |
1667 | ||
1668 | Cond := Build_Discriminant_Checks (N, T_Typ); | |
1669 | ||
3cce7f32 | 1670 | -- If Lhs is set and is a parameter, then the condition is guarded by: |
1671 | -- lhs'constrained and then (condition built above) | |
ee6ba406 | 1672 | |
1673 | if Present (Param_Entity (Lhs)) then | |
1674 | Cond := | |
1675 | Make_And_Then (Loc, | |
1676 | Left_Opnd => | |
1677 | Make_Attribute_Reference (Loc, | |
1678 | Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc), | |
1679 | Attribute_Name => Name_Constrained), | |
1680 | Right_Opnd => Cond); | |
1681 | end if; | |
1682 | ||
1683 | if Do_Access then | |
1684 | Cond := Guard_Access (Cond, Loc, N); | |
1685 | end if; | |
1686 | ||
1687 | Insert_Action (N, | |
f15731c4 | 1688 | Make_Raise_Constraint_Error (Loc, |
1689 | Condition => Cond, | |
1690 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 1691 | end Apply_Discriminant_Check; |
1692 | ||
2fe22c69 | 1693 | ------------------------- |
1694 | -- Apply_Divide_Checks -- | |
1695 | ------------------------- | |
ee6ba406 | 1696 | |
2fe22c69 | 1697 | procedure Apply_Divide_Checks (N : Node_Id) is |
ee6ba406 | 1698 | Loc : constant Source_Ptr := Sloc (N); |
1699 | Typ : constant Entity_Id := Etype (N); | |
1700 | Left : constant Node_Id := Left_Opnd (N); | |
1701 | Right : constant Node_Id := Right_Opnd (N); | |
1702 | ||
db415383 | 1703 | Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
2fe22c69 | 1704 | -- Current overflow checking mode |
1705 | ||
ee6ba406 | 1706 | LLB : Uint; |
1707 | Llo : Uint; | |
1708 | Lhi : Uint; | |
1709 | LOK : Boolean; | |
1710 | Rlo : Uint; | |
1711 | Rhi : Uint; | |
2fe22c69 | 1712 | ROK : Boolean; |
96da3284 | 1713 | |
1714 | pragma Warnings (Off, Lhi); | |
1715 | -- Don't actually use this value | |
ee6ba406 | 1716 | |
1717 | begin | |
0df9d43f | 1718 | -- If we are operating in MINIMIZED or ELIMINATED mode, and we are |
1719 | -- operating on signed integer types, then the only thing this routine | |
1720 | -- does is to call Apply_Arithmetic_Overflow_Minimized_Eliminated. That | |
1721 | -- procedure will (possibly later on during recursive downward calls), | |
1722 | -- ensure that any needed overflow/division checks are properly applied. | |
2fe22c69 | 1723 | |
1724 | if Mode in Minimized_Or_Eliminated | |
2fe22c69 | 1725 | and then Is_Signed_Integer_Type (Typ) |
1726 | then | |
1727 | Apply_Arithmetic_Overflow_Minimized_Eliminated (N); | |
1728 | return; | |
1729 | end if; | |
1730 | ||
1731 | -- Proceed here in SUPPRESSED or CHECKED modes | |
1732 | ||
6dbcfcd9 | 1733 | if Full_Expander_Active |
13dbf220 | 1734 | and then not Backend_Divide_Checks_On_Target |
1735 | and then Check_Needed (Right, Division_Check) | |
ee6ba406 | 1736 | then |
9c486805 | 1737 | Determine_Range (Right, ROK, Rlo, Rhi, Assume_Valid => True); |
ee6ba406 | 1738 | |
2fe22c69 | 1739 | -- Deal with division check |
ee6ba406 | 1740 | |
2fe22c69 | 1741 | if Do_Division_Check (N) |
1742 | and then not Division_Checks_Suppressed (Typ) | |
1743 | then | |
1744 | Apply_Division_Check (N, Rlo, Rhi, ROK); | |
ee6ba406 | 1745 | end if; |
1746 | ||
2fe22c69 | 1747 | -- Deal with overflow check |
1748 | ||
0df9d43f | 1749 | if Do_Overflow_Check (N) |
1750 | and then not Overflow_Checks_Suppressed (Etype (N)) | |
1751 | then | |
2fe22c69 | 1752 | |
1753 | -- Test for extremely annoying case of xxx'First divided by -1 | |
1754 | -- for division of signed integer types (only overflow case). | |
ee6ba406 | 1755 | |
ee6ba406 | 1756 | if Nkind (N) = N_Op_Divide |
1757 | and then Is_Signed_Integer_Type (Typ) | |
1758 | then | |
9c486805 | 1759 | Determine_Range (Left, LOK, Llo, Lhi, Assume_Valid => True); |
ee6ba406 | 1760 | LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ))); |
1761 | ||
1762 | if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) | |
2fe22c69 | 1763 | and then |
1764 | ((not LOK) or else (Llo = LLB)) | |
ee6ba406 | 1765 | then |
1766 | Insert_Action (N, | |
1767 | Make_Raise_Constraint_Error (Loc, | |
1768 | Condition => | |
1769 | Make_And_Then (Loc, | |
2fe22c69 | 1770 | Left_Opnd => |
1771 | Make_Op_Eq (Loc, | |
1772 | Left_Opnd => | |
1773 | Duplicate_Subexpr_Move_Checks (Left), | |
1774 | Right_Opnd => Make_Integer_Literal (Loc, LLB)), | |
ee6ba406 | 1775 | |
2fe22c69 | 1776 | Right_Opnd => |
1777 | Make_Op_Eq (Loc, | |
1778 | Left_Opnd => Duplicate_Subexpr (Right), | |
1779 | Right_Opnd => Make_Integer_Literal (Loc, -1))), | |
ee6ba406 | 1780 | |
f15731c4 | 1781 | Reason => CE_Overflow_Check_Failed)); |
ee6ba406 | 1782 | end if; |
1783 | end if; | |
1784 | end if; | |
1785 | end if; | |
2fe22c69 | 1786 | end Apply_Divide_Checks; |
1787 | ||
1788 | -------------------------- | |
1789 | -- Apply_Division_Check -- | |
1790 | -------------------------- | |
1791 | ||
1792 | procedure Apply_Division_Check | |
1793 | (N : Node_Id; | |
1794 | Rlo : Uint; | |
1795 | Rhi : Uint; | |
1796 | ROK : Boolean) | |
1797 | is | |
1798 | pragma Assert (Do_Division_Check (N)); | |
1799 | ||
1800 | Loc : constant Source_Ptr := Sloc (N); | |
1801 | Right : constant Node_Id := Right_Opnd (N); | |
1802 | ||
1803 | begin | |
1804 | if Full_Expander_Active | |
1805 | and then not Backend_Divide_Checks_On_Target | |
1806 | and then Check_Needed (Right, Division_Check) | |
1807 | then | |
1808 | -- See if division by zero possible, and if so generate test. This | |
1809 | -- part of the test is not controlled by the -gnato switch, since | |
1810 | -- it is a Division_Check and not an Overflow_Check. | |
1811 | ||
1812 | if Do_Division_Check (N) then | |
1813 | if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then | |
1814 | Insert_Action (N, | |
1815 | Make_Raise_Constraint_Error (Loc, | |
1816 | Condition => | |
1817 | Make_Op_Eq (Loc, | |
1818 | Left_Opnd => Duplicate_Subexpr_Move_Checks (Right), | |
1819 | Right_Opnd => Make_Integer_Literal (Loc, 0)), | |
1820 | Reason => CE_Divide_By_Zero)); | |
1821 | end if; | |
1822 | end if; | |
1823 | end if; | |
1824 | end Apply_Division_Check; | |
ee6ba406 | 1825 | |
5329ca64 | 1826 | ---------------------------------- |
1827 | -- Apply_Float_Conversion_Check -- | |
1828 | ---------------------------------- | |
1829 | ||
feff2f05 | 1830 | -- Let F and I be the source and target types of the conversion. The RM |
1831 | -- specifies that a floating-point value X is rounded to the nearest | |
1832 | -- integer, with halfway cases being rounded away from zero. The rounded | |
1833 | -- value of X is checked against I'Range. | |
1834 | ||
1835 | -- The catch in the above paragraph is that there is no good way to know | |
1836 | -- whether the round-to-integer operation resulted in overflow. A remedy is | |
1837 | -- to perform a range check in the floating-point domain instead, however: | |
5329ca64 | 1838 | |
5329ca64 | 1839 | -- (1) The bounds may not be known at compile time |
2af58f67 | 1840 | -- (2) The check must take into account rounding or truncation. |
5329ca64 | 1841 | -- (3) The range of type I may not be exactly representable in F. |
2af58f67 | 1842 | -- (4) For the rounding case, The end-points I'First - 0.5 and |
1843 | -- I'Last + 0.5 may or may not be in range, depending on the | |
1844 | -- sign of I'First and I'Last. | |
5329ca64 | 1845 | -- (5) X may be a NaN, which will fail any comparison |
1846 | ||
2af58f67 | 1847 | -- The following steps correctly convert X with rounding: |
feff2f05 | 1848 | |
5329ca64 | 1849 | -- (1) If either I'First or I'Last is not known at compile time, use |
1850 | -- I'Base instead of I in the next three steps and perform a | |
1851 | -- regular range check against I'Range after conversion. | |
1852 | -- (2) If I'First - 0.5 is representable in F then let Lo be that | |
1853 | -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be | |
2af58f67 | 1854 | -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First). |
1855 | -- In other words, take one of the closest floating-point numbers | |
1856 | -- (which is an integer value) to I'First, and see if it is in | |
1857 | -- range or not. | |
5329ca64 | 1858 | -- (3) If I'Last + 0.5 is representable in F then let Hi be that value |
1859 | -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be | |
2af58f67 | 1860 | -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last). |
5329ca64 | 1861 | -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo) |
1862 | -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi) | |
1863 | ||
2af58f67 | 1864 | -- For the truncating case, replace steps (2) and (3) as follows: |
1865 | -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK | |
1866 | -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let | |
1867 | -- Lo_OK be True. | |
1868 | -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK | |
1869 | -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let | |
141d591a | 1870 | -- Hi_OK be True. |
2af58f67 | 1871 | |
5329ca64 | 1872 | procedure Apply_Float_Conversion_Check |
1873 | (Ck_Node : Node_Id; | |
1874 | Target_Typ : Entity_Id) | |
1875 | is | |
feff2f05 | 1876 | LB : constant Node_Id := Type_Low_Bound (Target_Typ); |
1877 | HB : constant Node_Id := Type_High_Bound (Target_Typ); | |
5329ca64 | 1878 | Loc : constant Source_Ptr := Sloc (Ck_Node); |
1879 | Expr_Type : constant Entity_Id := Base_Type (Etype (Ck_Node)); | |
feff2f05 | 1880 | Target_Base : constant Entity_Id := |
b6341c67 | 1881 | Implementation_Base_Type (Target_Typ); |
feff2f05 | 1882 | |
2af58f67 | 1883 | Par : constant Node_Id := Parent (Ck_Node); |
1884 | pragma Assert (Nkind (Par) = N_Type_Conversion); | |
1885 | -- Parent of check node, must be a type conversion | |
1886 | ||
1887 | Truncate : constant Boolean := Float_Truncate (Par); | |
1888 | Max_Bound : constant Uint := | |
b6341c67 | 1889 | UI_Expon |
1890 | (Machine_Radix_Value (Expr_Type), | |
1891 | Machine_Mantissa_Value (Expr_Type) - 1) - 1; | |
2af58f67 | 1892 | |
5329ca64 | 1893 | -- Largest bound, so bound plus or minus half is a machine number of F |
1894 | ||
feff2f05 | 1895 | Ifirst, Ilast : Uint; |
1896 | -- Bounds of integer type | |
1897 | ||
1898 | Lo, Hi : Ureal; | |
1899 | -- Bounds to check in floating-point domain | |
5329ca64 | 1900 | |
feff2f05 | 1901 | Lo_OK, Hi_OK : Boolean; |
1902 | -- True iff Lo resp. Hi belongs to I'Range | |
5329ca64 | 1903 | |
feff2f05 | 1904 | Lo_Chk, Hi_Chk : Node_Id; |
1905 | -- Expressions that are False iff check fails | |
1906 | ||
1907 | Reason : RT_Exception_Code; | |
5329ca64 | 1908 | |
1909 | begin | |
1910 | if not Compile_Time_Known_Value (LB) | |
1911 | or not Compile_Time_Known_Value (HB) | |
1912 | then | |
1913 | declare | |
feff2f05 | 1914 | -- First check that the value falls in the range of the base type, |
1915 | -- to prevent overflow during conversion and then perform a | |
1916 | -- regular range check against the (dynamic) bounds. | |
5329ca64 | 1917 | |
5329ca64 | 1918 | pragma Assert (Target_Base /= Target_Typ); |
5329ca64 | 1919 | |
46eb6933 | 1920 | Temp : constant Entity_Id := Make_Temporary (Loc, 'T', Par); |
5329ca64 | 1921 | |
1922 | begin | |
1923 | Apply_Float_Conversion_Check (Ck_Node, Target_Base); | |
1924 | Set_Etype (Temp, Target_Base); | |
1925 | ||
1926 | Insert_Action (Parent (Par), | |
1927 | Make_Object_Declaration (Loc, | |
1928 | Defining_Identifier => Temp, | |
1929 | Object_Definition => New_Occurrence_Of (Target_Typ, Loc), | |
1930 | Expression => New_Copy_Tree (Par)), | |
1931 | Suppress => All_Checks); | |
1932 | ||
1933 | Insert_Action (Par, | |
1934 | Make_Raise_Constraint_Error (Loc, | |
1935 | Condition => | |
1936 | Make_Not_In (Loc, | |
1937 | Left_Opnd => New_Occurrence_Of (Temp, Loc), | |
1938 | Right_Opnd => New_Occurrence_Of (Target_Typ, Loc)), | |
1939 | Reason => CE_Range_Check_Failed)); | |
1940 | Rewrite (Par, New_Occurrence_Of (Temp, Loc)); | |
1941 | ||
1942 | return; | |
1943 | end; | |
1944 | end if; | |
1945 | ||
7d86aa98 | 1946 | -- Get the (static) bounds of the target type |
5329ca64 | 1947 | |
1948 | Ifirst := Expr_Value (LB); | |
1949 | Ilast := Expr_Value (HB); | |
1950 | ||
7d86aa98 | 1951 | -- A simple optimization: if the expression is a universal literal, |
1952 | -- we can do the comparison with the bounds and the conversion to | |
1953 | -- an integer type statically. The range checks are unchanged. | |
1954 | ||
1955 | if Nkind (Ck_Node) = N_Real_Literal | |
1956 | and then Etype (Ck_Node) = Universal_Real | |
1957 | and then Is_Integer_Type (Target_Typ) | |
1958 | and then Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
1959 | then | |
1960 | declare | |
1961 | Int_Val : constant Uint := UR_To_Uint (Realval (Ck_Node)); | |
1962 | ||
1963 | begin | |
1964 | if Int_Val <= Ilast and then Int_Val >= Ifirst then | |
1965 | ||
4309515d | 1966 | -- Conversion is safe |
7d86aa98 | 1967 | |
1968 | Rewrite (Parent (Ck_Node), | |
1969 | Make_Integer_Literal (Loc, UI_To_Int (Int_Val))); | |
1970 | Analyze_And_Resolve (Parent (Ck_Node), Target_Typ); | |
1971 | return; | |
1972 | end if; | |
1973 | end; | |
1974 | end if; | |
1975 | ||
5329ca64 | 1976 | -- Check against lower bound |
1977 | ||
2af58f67 | 1978 | if Truncate and then Ifirst > 0 then |
1979 | Lo := Pred (Expr_Type, UR_From_Uint (Ifirst)); | |
1980 | Lo_OK := False; | |
1981 | ||
1982 | elsif Truncate then | |
1983 | Lo := Succ (Expr_Type, UR_From_Uint (Ifirst - 1)); | |
1984 | Lo_OK := True; | |
1985 | ||
1986 | elsif abs (Ifirst) < Max_Bound then | |
5329ca64 | 1987 | Lo := UR_From_Uint (Ifirst) - Ureal_Half; |
1988 | Lo_OK := (Ifirst > 0); | |
2af58f67 | 1989 | |
5329ca64 | 1990 | else |
1991 | Lo := Machine (Expr_Type, UR_From_Uint (Ifirst), Round_Even, Ck_Node); | |
1992 | Lo_OK := (Lo >= UR_From_Uint (Ifirst)); | |
1993 | end if; | |
1994 | ||
1995 | if Lo_OK then | |
1996 | ||
1997 | -- Lo_Chk := (X >= Lo) | |
1998 | ||
1999 | Lo_Chk := Make_Op_Ge (Loc, | |
2000 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2001 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
2002 | ||
2003 | else | |
2004 | -- Lo_Chk := (X > Lo) | |
2005 | ||
2006 | Lo_Chk := Make_Op_Gt (Loc, | |
2007 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2008 | Right_Opnd => Make_Real_Literal (Loc, Lo)); | |
2009 | end if; | |
2010 | ||
2011 | -- Check against higher bound | |
2012 | ||
2af58f67 | 2013 | if Truncate and then Ilast < 0 then |
2014 | Hi := Succ (Expr_Type, UR_From_Uint (Ilast)); | |
b2c42753 | 2015 | Hi_OK := False; |
2af58f67 | 2016 | |
2017 | elsif Truncate then | |
2018 | Hi := Pred (Expr_Type, UR_From_Uint (Ilast + 1)); | |
2019 | Hi_OK := True; | |
2020 | ||
2021 | elsif abs (Ilast) < Max_Bound then | |
5329ca64 | 2022 | Hi := UR_From_Uint (Ilast) + Ureal_Half; |
2023 | Hi_OK := (Ilast < 0); | |
2024 | else | |
2025 | Hi := Machine (Expr_Type, UR_From_Uint (Ilast), Round_Even, Ck_Node); | |
2026 | Hi_OK := (Hi <= UR_From_Uint (Ilast)); | |
2027 | end if; | |
2028 | ||
2029 | if Hi_OK then | |
2030 | ||
2031 | -- Hi_Chk := (X <= Hi) | |
2032 | ||
2033 | Hi_Chk := Make_Op_Le (Loc, | |
2034 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2035 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
2036 | ||
2037 | else | |
2038 | -- Hi_Chk := (X < Hi) | |
2039 | ||
2040 | Hi_Chk := Make_Op_Lt (Loc, | |
2041 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), | |
2042 | Right_Opnd => Make_Real_Literal (Loc, Hi)); | |
2043 | end if; | |
2044 | ||
feff2f05 | 2045 | -- If the bounds of the target type are the same as those of the base |
2046 | -- type, the check is an overflow check as a range check is not | |
2047 | -- performed in these cases. | |
5329ca64 | 2048 | |
2049 | if Expr_Value (Type_Low_Bound (Target_Base)) = Ifirst | |
2050 | and then Expr_Value (Type_High_Bound (Target_Base)) = Ilast | |
2051 | then | |
2052 | Reason := CE_Overflow_Check_Failed; | |
2053 | else | |
2054 | Reason := CE_Range_Check_Failed; | |
2055 | end if; | |
2056 | ||
2057 | -- Raise CE if either conditions does not hold | |
2058 | ||
2059 | Insert_Action (Ck_Node, | |
2060 | Make_Raise_Constraint_Error (Loc, | |
05fcfafb | 2061 | Condition => Make_Op_Not (Loc, Make_And_Then (Loc, Lo_Chk, Hi_Chk)), |
5329ca64 | 2062 | Reason => Reason)); |
2063 | end Apply_Float_Conversion_Check; | |
2064 | ||
ee6ba406 | 2065 | ------------------------ |
2066 | -- Apply_Length_Check -- | |
2067 | ------------------------ | |
2068 | ||
2069 | procedure Apply_Length_Check | |
2070 | (Ck_Node : Node_Id; | |
2071 | Target_Typ : Entity_Id; | |
2072 | Source_Typ : Entity_Id := Empty) | |
2073 | is | |
2074 | begin | |
2075 | Apply_Selected_Length_Checks | |
2076 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
2077 | end Apply_Length_Check; | |
2078 | ||
3b045963 | 2079 | ------------------------------------- |
2080 | -- Apply_Parameter_Aliasing_Checks -- | |
2081 | ------------------------------------- | |
b73adb97 | 2082 | |
3b045963 | 2083 | procedure Apply_Parameter_Aliasing_Checks |
2084 | (Call : Node_Id; | |
2085 | Subp : Entity_Id) | |
2086 | is | |
2087 | function May_Cause_Aliasing | |
2088 | (Formal_1 : Entity_Id; | |
2089 | Formal_2 : Entity_Id) return Boolean; | |
2090 | -- Determine whether two formal parameters can alias each other | |
2091 | -- depending on their modes. | |
2092 | ||
2093 | function Original_Actual (N : Node_Id) return Node_Id; | |
2094 | -- The expander may replace an actual with a temporary for the sake of | |
2095 | -- side effect removal. The temporary may hide a potential aliasing as | |
2096 | -- it does not share the address of the actual. This routine attempts | |
2097 | -- to retrieve the original actual. | |
2098 | ||
2099 | ------------------------ | |
2100 | -- May_Cause_Aliasing -- | |
2101 | ------------------------ | |
b73adb97 | 2102 | |
3b045963 | 2103 | function May_Cause_Aliasing |
4a9e7f0c | 2104 | (Formal_1 : Entity_Id; |
3b045963 | 2105 | Formal_2 : Entity_Id) return Boolean |
2106 | is | |
2107 | begin | |
2108 | -- The following combination cannot lead to aliasing | |
2109 | ||
2110 | -- Formal 1 Formal 2 | |
2111 | -- IN IN | |
2112 | ||
2113 | if Ekind (Formal_1) = E_In_Parameter | |
a45d946f | 2114 | and then |
2115 | Ekind (Formal_2) = E_In_Parameter | |
3b045963 | 2116 | then |
2117 | return False; | |
2118 | ||
2119 | -- The following combinations may lead to aliasing | |
2120 | ||
2121 | -- Formal 1 Formal 2 | |
2122 | -- IN OUT | |
2123 | -- IN IN OUT | |
2124 | -- OUT IN | |
2125 | -- OUT IN OUT | |
2126 | -- OUT OUT | |
2127 | ||
2128 | else | |
2129 | return True; | |
2130 | end if; | |
2131 | end May_Cause_Aliasing; | |
2132 | ||
2133 | --------------------- | |
2134 | -- Original_Actual -- | |
2135 | --------------------- | |
2136 | ||
2137 | function Original_Actual (N : Node_Id) return Node_Id is | |
2138 | begin | |
2139 | if Nkind (N) = N_Type_Conversion then | |
2140 | return Expression (N); | |
2141 | ||
2142 | -- The expander created a temporary to capture the result of a type | |
2143 | -- conversion where the expression is the real actual. | |
2144 | ||
2145 | elsif Nkind (N) = N_Identifier | |
2146 | and then Present (Original_Node (N)) | |
2147 | and then Nkind (Original_Node (N)) = N_Type_Conversion | |
2148 | then | |
2149 | return Expression (Original_Node (N)); | |
2150 | end if; | |
2151 | ||
2152 | return N; | |
2153 | end Original_Actual; | |
2154 | ||
2155 | -- Local variables | |
2156 | ||
2157 | Loc : constant Source_Ptr := Sloc (Call); | |
2158 | Actual_1 : Node_Id; | |
2159 | Actual_2 : Node_Id; | |
2160 | Check : Node_Id; | |
2161 | Cond : Node_Id; | |
2162 | Formal_1 : Entity_Id; | |
2163 | Formal_2 : Entity_Id; | |
2164 | ||
2165 | -- Start of processing for Apply_Parameter_Aliasing_Checks | |
2166 | ||
2167 | begin | |
2168 | Cond := Empty; | |
2169 | ||
2170 | Actual_1 := First_Actual (Call); | |
2171 | Formal_1 := First_Formal (Subp); | |
2172 | while Present (Actual_1) and then Present (Formal_1) loop | |
2173 | ||
2174 | -- Ensure that the actual is an object that is not passed by value. | |
2175 | -- Elementary types are always passed by value, therefore actuals of | |
2176 | -- such types cannot lead to aliasing. | |
2177 | ||
2178 | if Is_Object_Reference (Original_Actual (Actual_1)) | |
2179 | and then not Is_Elementary_Type (Etype (Original_Actual (Actual_1))) | |
2180 | then | |
2181 | Actual_2 := Next_Actual (Actual_1); | |
2182 | Formal_2 := Next_Formal (Formal_1); | |
2183 | while Present (Actual_2) and then Present (Formal_2) loop | |
2184 | ||
2185 | -- The other actual we are testing against must also denote | |
2186 | -- a non pass-by-value object. Generate the check only when | |
2187 | -- the mode of the two formals may lead to aliasing. | |
2188 | ||
2189 | if Is_Object_Reference (Original_Actual (Actual_2)) | |
2190 | and then not | |
2191 | Is_Elementary_Type (Etype (Original_Actual (Actual_2))) | |
2192 | and then May_Cause_Aliasing (Formal_1, Formal_2) | |
2193 | then | |
2194 | -- Generate: | |
2195 | -- Actual_1'Overlaps_Storage (Actual_2) | |
2196 | ||
2197 | Check := | |
2198 | Make_Attribute_Reference (Loc, | |
2199 | Prefix => | |
2200 | New_Copy_Tree (Original_Actual (Actual_1)), | |
2201 | Attribute_Name => Name_Overlaps_Storage, | |
2202 | Expressions => | |
2203 | New_List (New_Copy_Tree (Original_Actual (Actual_2)))); | |
2204 | ||
2205 | if No (Cond) then | |
2206 | Cond := Check; | |
2207 | else | |
2208 | Cond := | |
2209 | Make_And_Then (Loc, | |
2210 | Left_Opnd => Cond, | |
2211 | Right_Opnd => Check); | |
2212 | end if; | |
2213 | end if; | |
2214 | ||
2215 | Next_Actual (Actual_2); | |
2216 | Next_Formal (Formal_2); | |
2217 | end loop; | |
2218 | end if; | |
2219 | ||
2220 | Next_Actual (Actual_1); | |
2221 | Next_Formal (Formal_1); | |
2222 | end loop; | |
2223 | ||
2224 | -- Place the check right before the call | |
2225 | ||
2226 | if Present (Cond) then | |
2227 | Insert_Action (Call, | |
2228 | Make_Raise_Program_Error (Loc, | |
2229 | Condition => Cond, | |
2230 | Reason => PE_Explicit_Raise)); | |
2231 | end if; | |
2232 | end Apply_Parameter_Aliasing_Checks; | |
2233 | ||
2234 | ------------------------------------- | |
2235 | -- Apply_Parameter_Validity_Checks -- | |
2236 | ------------------------------------- | |
2237 | ||
2238 | procedure Apply_Parameter_Validity_Checks (Subp : Entity_Id) is | |
2239 | Subp_Decl : Node_Id; | |
b73adb97 | 2240 | |
4a9e7f0c | 2241 | procedure Add_Validity_Check |
2242 | (Context : Entity_Id; | |
2243 | PPC_Nam : Name_Id; | |
2244 | For_Result : Boolean := False); | |
2245 | -- Add a single 'Valid[_Scalar] check which verifies the initialization | |
2246 | -- of Context. PPC_Nam denotes the pre or post condition pragma name. | |
2247 | -- Set flag For_Result when to verify the result of a function. | |
b73adb97 | 2248 | |
4a9e7f0c | 2249 | procedure Build_PPC_Pragma (PPC_Nam : Name_Id; Check : Node_Id); |
2250 | -- Create a pre or post condition pragma with name PPC_Nam which | |
2251 | -- tests expression Check. | |
b73adb97 | 2252 | |
b73adb97 | 2253 | ------------------------ |
2254 | -- Add_Validity_Check -- | |
2255 | ------------------------ | |
2256 | ||
2257 | procedure Add_Validity_Check | |
2258 | (Context : Entity_Id; | |
4a9e7f0c | 2259 | PPC_Nam : Name_Id; |
b73adb97 | 2260 | For_Result : Boolean := False) |
2261 | is | |
4a9e7f0c | 2262 | Loc : constant Source_Ptr := Sloc (Subp); |
2263 | Typ : constant Entity_Id := Etype (Context); | |
b73adb97 | 2264 | Check : Node_Id; |
2265 | Nam : Name_Id; | |
2266 | ||
2267 | begin | |
2268 | -- Pick the proper version of 'Valid depending on the type of the | |
2269 | -- context. If the context is not eligible for such a check, return. | |
2270 | ||
2271 | if Is_Scalar_Type (Typ) then | |
2272 | Nam := Name_Valid; | |
2273 | elsif not No_Scalar_Parts (Typ) then | |
2274 | Nam := Name_Valid_Scalars; | |
2275 | else | |
2276 | return; | |
2277 | end if; | |
2278 | ||
2279 | -- Step 1: Create the expression to verify the validity of the | |
2280 | -- context. | |
2281 | ||
2282 | Check := New_Reference_To (Context, Loc); | |
2283 | ||
2284 | -- When processing a function result, use 'Result. Generate | |
2285 | -- Context'Result | |
2286 | ||
2287 | if For_Result then | |
2288 | Check := | |
2289 | Make_Attribute_Reference (Loc, | |
2290 | Prefix => Check, | |
2291 | Attribute_Name => Name_Result); | |
2292 | end if; | |
2293 | ||
2294 | -- Generate: | |
2295 | -- Context['Result]'Valid[_Scalars] | |
2296 | ||
2297 | Check := | |
2298 | Make_Attribute_Reference (Loc, | |
2299 | Prefix => Check, | |
2300 | Attribute_Name => Nam); | |
2301 | ||
4a9e7f0c | 2302 | -- Step 2: Create a pre or post condition pragma |
2303 | ||
2304 | Build_PPC_Pragma (PPC_Nam, Check); | |
2305 | end Add_Validity_Check; | |
2306 | ||
2307 | ---------------------- | |
2308 | -- Build_PPC_Pragma -- | |
2309 | ---------------------- | |
b73adb97 | 2310 | |
4a9e7f0c | 2311 | procedure Build_PPC_Pragma (PPC_Nam : Name_Id; Check : Node_Id) is |
7c443ae8 | 2312 | Loc : constant Source_Ptr := Sloc (Subp); |
2313 | Decls : List_Id; | |
2314 | Prag : Node_Id; | |
4a9e7f0c | 2315 | |
2316 | begin | |
2317 | Prag := | |
2318 | Make_Pragma (Loc, | |
2319 | Pragma_Identifier => Make_Identifier (Loc, PPC_Nam), | |
2320 | Pragma_Argument_Associations => New_List ( | |
2321 | Make_Pragma_Argument_Association (Loc, | |
2322 | Chars => Name_Check, | |
2323 | Expression => Check))); | |
2324 | ||
2325 | -- Add a message unless exception messages are suppressed | |
2326 | ||
2327 | if not Exception_Locations_Suppressed then | |
2328 | Append_To (Pragma_Argument_Associations (Prag), | |
2329 | Make_Pragma_Argument_Association (Loc, | |
2330 | Chars => Name_Message, | |
2331 | Expression => | |
2332 | Make_String_Literal (Loc, | |
2333 | Strval => "failed " & Get_Name_String (PPC_Nam) & | |
2334 | " from " & Build_Location_String (Loc)))); | |
2335 | end if; | |
2336 | ||
2337 | -- Insert the pragma in the tree | |
2338 | ||
2339 | if Nkind (Parent (Subp_Decl)) = N_Compilation_Unit then | |
2340 | Add_Global_Declaration (Prag); | |
7c443ae8 | 2341 | Analyze (Prag); |
2342 | ||
2343 | -- PPC pragmas associated with subprogram bodies must be inserted in | |
2344 | -- the declarative part of the body. | |
2345 | ||
2346 | elsif Nkind (Subp_Decl) = N_Subprogram_Body then | |
2347 | Decls := Declarations (Subp_Decl); | |
2348 | ||
2349 | if No (Decls) then | |
2350 | Decls := New_List; | |
2351 | Set_Declarations (Subp_Decl, Decls); | |
2352 | end if; | |
2353 | ||
1bd93de5 | 2354 | Prepend_To (Decls, Prag); |
7c443ae8 | 2355 | |
2356 | -- Ensure the proper visibility of the subprogram body and its | |
2357 | -- parameters. | |
2358 | ||
2359 | Push_Scope (Subp); | |
2360 | Analyze (Prag); | |
2361 | Pop_Scope; | |
2362 | ||
2363 | -- For subprogram declarations insert the PPC pragma right after the | |
2364 | -- declarative node. | |
2365 | ||
b73adb97 | 2366 | else |
7c443ae8 | 2367 | Insert_After_And_Analyze (Subp_Decl, Prag); |
b73adb97 | 2368 | end if; |
4a9e7f0c | 2369 | end Build_PPC_Pragma; |
2370 | ||
2371 | -- Local variables | |
2372 | ||
2373 | Formal : Entity_Id; | |
4a9e7f0c | 2374 | Subp_Spec : Node_Id; |
2375 | ||
3b045963 | 2376 | -- Start of processing for Apply_Parameter_Validity_Checks |
b73adb97 | 2377 | |
2378 | begin | |
4a9e7f0c | 2379 | -- Extract the subprogram specification and declaration nodes |
b73adb97 | 2380 | |
4a9e7f0c | 2381 | Subp_Spec := Parent (Subp); |
a45d946f | 2382 | |
4a9e7f0c | 2383 | if Nkind (Subp_Spec) = N_Defining_Program_Unit_Name then |
2384 | Subp_Spec := Parent (Subp_Spec); | |
2385 | end if; | |
a45d946f | 2386 | |
4a9e7f0c | 2387 | Subp_Decl := Parent (Subp_Spec); |
9e58d7ed | 2388 | |
b73adb97 | 2389 | if not Comes_From_Source (Subp) |
4a9e7f0c | 2390 | |
2391 | -- Do not process formal subprograms because the corresponding actual | |
2392 | -- will receive the proper checks when the instance is analyzed. | |
2393 | ||
2394 | or else Is_Formal_Subprogram (Subp) | |
2395 | ||
a45d946f | 2396 | -- Do not process imported subprograms since pre and post conditions |
2397 | -- are never verified on routines coming from a different language. | |
4a9e7f0c | 2398 | |
b73adb97 | 2399 | or else Is_Imported (Subp) |
2400 | or else Is_Intrinsic_Subprogram (Subp) | |
4a9e7f0c | 2401 | |
a45d946f | 2402 | -- The PPC pragmas generated by this routine do not correspond to |
2403 | -- source aspects, therefore they cannot be applied to abstract | |
2404 | -- subprograms. | |
4a9e7f0c | 2405 | |
7c443ae8 | 2406 | or else Nkind (Subp_Decl) = N_Abstract_Subprogram_Declaration |
4a9e7f0c | 2407 | |
a45d946f | 2408 | -- Do not consider subprogram renaminds because the renamed entity |
2409 | -- already has the proper PPC pragmas. | |
1bd93de5 | 2410 | |
2411 | or else Nkind (Subp_Decl) = N_Subprogram_Renaming_Declaration | |
2412 | ||
a45d946f | 2413 | -- Do not process null procedures because there is no benefit of |
2414 | -- adding the checks to a no action routine. | |
4a9e7f0c | 2415 | |
2416 | or else (Nkind (Subp_Spec) = N_Procedure_Specification | |
a45d946f | 2417 | and then Null_Present (Subp_Spec)) |
b73adb97 | 2418 | then |
2419 | return; | |
2420 | end if; | |
2421 | ||
4a9e7f0c | 2422 | -- Inspect all the formals applying aliasing and scalar initialization |
2423 | -- checks where applicable. | |
b73adb97 | 2424 | |
2425 | Formal := First_Formal (Subp); | |
2426 | while Present (Formal) loop | |
4a9e7f0c | 2427 | |
2428 | -- Generate the following scalar initialization checks for each | |
2429 | -- formal parameter: | |
2430 | ||
2431 | -- mode IN - Pre => Formal'Valid[_Scalars] | |
2432 | -- mode IN OUT - Pre, Post => Formal'Valid[_Scalars] | |
2433 | -- mode OUT - Post => Formal'Valid[_Scalars] | |
2434 | ||
2435 | if Check_Validity_Of_Parameters then | |
2436 | if Ekind_In (Formal, E_In_Parameter, E_In_Out_Parameter) then | |
2437 | Add_Validity_Check (Formal, Name_Precondition, False); | |
2438 | end if; | |
2439 | ||
2440 | if Ekind_In (Formal, E_In_Out_Parameter, E_Out_Parameter) then | |
2441 | Add_Validity_Check (Formal, Name_Postcondition, False); | |
2442 | end if; | |
b73adb97 | 2443 | end if; |
2444 | ||
b73adb97 | 2445 | Next_Formal (Formal); |
2446 | end loop; | |
2447 | ||
a45d946f | 2448 | -- Generate following scalar initialization check for function result: |
4a9e7f0c | 2449 | |
2450 | -- Post => Subp'Result'Valid[_Scalars] | |
b73adb97 | 2451 | |
a45d946f | 2452 | if Check_Validity_Of_Parameters and then Ekind (Subp) = E_Function then |
4a9e7f0c | 2453 | Add_Validity_Check (Subp, Name_Postcondition, True); |
b73adb97 | 2454 | end if; |
3b045963 | 2455 | end Apply_Parameter_Validity_Checks; |
b73adb97 | 2456 | |
7aafae1c | 2457 | --------------------------- |
2458 | -- Apply_Predicate_Check -- | |
2459 | --------------------------- | |
2460 | ||
2461 | procedure Apply_Predicate_Check (N : Node_Id; Typ : Entity_Id) is | |
301d5ec3 | 2462 | S : Entity_Id; |
9e58d7ed | 2463 | |
7aafae1c | 2464 | begin |
701d57a4 | 2465 | if Present (Predicate_Function (Typ)) then |
301d5ec3 | 2466 | |
2467 | -- A predicate check does not apply within internally generated | |
2468 | -- subprograms, such as TSS functions. | |
2469 | ||
2470 | S := Current_Scope; | |
9e58d7ed | 2471 | while Present (S) and then not Is_Subprogram (S) loop |
301d5ec3 | 2472 | S := Scope (S); |
2473 | end loop; | |
2474 | ||
9e58d7ed | 2475 | if Present (S) and then Get_TSS_Name (S) /= TSS_Null then |
301d5ec3 | 2476 | return; |
22631b41 | 2477 | |
96a2d100 | 2478 | -- If the check appears within the predicate function itself, it |
2479 | -- means that the user specified a check whose formal is the | |
2480 | -- predicated subtype itself, rather than some covering type. This | |
2481 | -- is likely to be a common error, and thus deserves a warning. | |
22631b41 | 2482 | |
2483 | elsif S = Predicate_Function (Typ) then | |
96a2d100 | 2484 | Error_Msg_N |
2485 | ("predicate check includes a function call that " | |
cb97ae5c | 2486 | & "requires a predicate check??", Parent (N)); |
96a2d100 | 2487 | Error_Msg_N |
cb97ae5c | 2488 | ("\this will result in infinite recursion??", Parent (N)); |
96a2d100 | 2489 | Insert_Action (N, |
61016a7a | 2490 | Make_Raise_Storage_Error (Sloc (N), |
2491 | Reason => SE_Infinite_Recursion)); | |
22631b41 | 2492 | |
61016a7a | 2493 | -- Here for normal case of predicate active. |
e6281d47 | 2494 | |
61016a7a | 2495 | else |
e6281d47 | 2496 | -- If the predicate is a static predicate and the operand is |
2497 | -- static, the predicate must be evaluated statically. If the | |
cac18f71 | 2498 | -- evaluation fails this is a static constraint error. This check |
2499 | -- is disabled in -gnatc mode, because the compiler is incapable | |
2500 | -- of evaluating static expressions in that case. | |
e6281d47 | 2501 | |
2502 | if Is_OK_Static_Expression (N) then | |
61016a7a | 2503 | if Present (Static_Predicate (Typ)) then |
a45d946f | 2504 | if Operating_Mode < Generate_Code |
2505 | or else Eval_Static_Predicate_Check (N, Typ) | |
cac18f71 | 2506 | then |
e6281d47 | 2507 | return; |
2508 | else | |
2509 | Error_Msg_NE | |
2510 | ("static expression fails static predicate check on&", | |
61016a7a | 2511 | N, Typ); |
e6281d47 | 2512 | end if; |
2513 | end if; | |
2514 | end if; | |
2515 | ||
301d5ec3 | 2516 | Insert_Action (N, |
2517 | Make_Predicate_Check (Typ, Duplicate_Subexpr (N))); | |
2518 | end if; | |
7aafae1c | 2519 | end if; |
2520 | end Apply_Predicate_Check; | |
2521 | ||
ee6ba406 | 2522 | ----------------------- |
2523 | -- Apply_Range_Check -- | |
2524 | ----------------------- | |
2525 | ||
2526 | procedure Apply_Range_Check | |
2527 | (Ck_Node : Node_Id; | |
2528 | Target_Typ : Entity_Id; | |
2529 | Source_Typ : Entity_Id := Empty) | |
2530 | is | |
2531 | begin | |
2532 | Apply_Selected_Range_Checks | |
2533 | (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); | |
2534 | end Apply_Range_Check; | |
2535 | ||
2536 | ------------------------------ | |
2537 | -- Apply_Scalar_Range_Check -- | |
2538 | ------------------------------ | |
2539 | ||
feff2f05 | 2540 | -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag |
2541 | -- off if it is already set on. | |
ee6ba406 | 2542 | |
2543 | procedure Apply_Scalar_Range_Check | |
2544 | (Expr : Node_Id; | |
2545 | Target_Typ : Entity_Id; | |
2546 | Source_Typ : Entity_Id := Empty; | |
2547 | Fixed_Int : Boolean := False) | |
2548 | is | |
2549 | Parnt : constant Node_Id := Parent (Expr); | |
2550 | S_Typ : Entity_Id; | |
2551 | Arr : Node_Id := Empty; -- initialize to prevent warning | |
2552 | Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning | |
2553 | OK : Boolean; | |
2554 | ||
2555 | Is_Subscr_Ref : Boolean; | |
2556 | -- Set true if Expr is a subscript | |
2557 | ||
2558 | Is_Unconstrained_Subscr_Ref : Boolean; | |
2559 | -- Set true if Expr is a subscript of an unconstrained array. In this | |
2560 | -- case we do not attempt to do an analysis of the value against the | |
2561 | -- range of the subscript, since we don't know the actual subtype. | |
2562 | ||
2563 | Int_Real : Boolean; | |
feff2f05 | 2564 | -- Set to True if Expr should be regarded as a real value even though |
2565 | -- the type of Expr might be discrete. | |
ee6ba406 | 2566 | |
2567 | procedure Bad_Value; | |
2568 | -- Procedure called if value is determined to be out of range | |
2569 | ||
9dfe12ae | 2570 | --------------- |
2571 | -- Bad_Value -- | |
2572 | --------------- | |
2573 | ||
ee6ba406 | 2574 | procedure Bad_Value is |
2575 | begin | |
2576 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 2577 | (Expr, "value not in range of}??", CE_Range_Check_Failed, |
ee6ba406 | 2578 | Ent => Target_Typ, |
2579 | Typ => Target_Typ); | |
2580 | end Bad_Value; | |
2581 | ||
9dfe12ae | 2582 | -- Start of processing for Apply_Scalar_Range_Check |
2583 | ||
ee6ba406 | 2584 | begin |
2af58f67 | 2585 | -- Return if check obviously not needed |
ee6ba406 | 2586 | |
2af58f67 | 2587 | if |
2588 | -- Not needed inside generic | |
ee6ba406 | 2589 | |
2af58f67 | 2590 | Inside_A_Generic |
2591 | ||
2592 | -- Not needed if previous error | |
2593 | ||
2594 | or else Target_Typ = Any_Type | |
2595 | or else Nkind (Expr) = N_Error | |
2596 | ||
2597 | -- Not needed for non-scalar type | |
2598 | ||
2599 | or else not Is_Scalar_Type (Target_Typ) | |
2600 | ||
2601 | -- Not needed if we know node raises CE already | |
2602 | ||
2603 | or else Raises_Constraint_Error (Expr) | |
ee6ba406 | 2604 | then |
2605 | return; | |
2606 | end if; | |
2607 | ||
2608 | -- Now, see if checks are suppressed | |
2609 | ||
2610 | Is_Subscr_Ref := | |
2611 | Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component; | |
2612 | ||
2613 | if Is_Subscr_Ref then | |
2614 | Arr := Prefix (Parnt); | |
2615 | Arr_Typ := Get_Actual_Subtype_If_Available (Arr); | |
cce84b09 | 2616 | |
a3a76ccc | 2617 | if Is_Access_Type (Arr_Typ) then |
245e87df | 2618 | Arr_Typ := Designated_Type (Arr_Typ); |
a3a76ccc | 2619 | end if; |
ee6ba406 | 2620 | end if; |
2621 | ||
2622 | if not Do_Range_Check (Expr) then | |
2623 | ||
2624 | -- Subscript reference. Check for Index_Checks suppressed | |
2625 | ||
2626 | if Is_Subscr_Ref then | |
2627 | ||
2628 | -- Check array type and its base type | |
2629 | ||
2630 | if Index_Checks_Suppressed (Arr_Typ) | |
9dfe12ae | 2631 | or else Index_Checks_Suppressed (Base_Type (Arr_Typ)) |
ee6ba406 | 2632 | then |
2633 | return; | |
2634 | ||
2635 | -- Check array itself if it is an entity name | |
2636 | ||
2637 | elsif Is_Entity_Name (Arr) | |
9dfe12ae | 2638 | and then Index_Checks_Suppressed (Entity (Arr)) |
ee6ba406 | 2639 | then |
2640 | return; | |
2641 | ||
2642 | -- Check expression itself if it is an entity name | |
2643 | ||
2644 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 2645 | and then Index_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 2646 | then |
2647 | return; | |
2648 | end if; | |
2649 | ||
2650 | -- All other cases, check for Range_Checks suppressed | |
2651 | ||
2652 | else | |
2653 | -- Check target type and its base type | |
2654 | ||
2655 | if Range_Checks_Suppressed (Target_Typ) | |
9dfe12ae | 2656 | or else Range_Checks_Suppressed (Base_Type (Target_Typ)) |
ee6ba406 | 2657 | then |
2658 | return; | |
2659 | ||
2660 | -- Check expression itself if it is an entity name | |
2661 | ||
2662 | elsif Is_Entity_Name (Expr) | |
9dfe12ae | 2663 | and then Range_Checks_Suppressed (Entity (Expr)) |
ee6ba406 | 2664 | then |
2665 | return; | |
2666 | ||
feff2f05 | 2667 | -- If Expr is part of an assignment statement, then check left |
2668 | -- side of assignment if it is an entity name. | |
ee6ba406 | 2669 | |
2670 | elsif Nkind (Parnt) = N_Assignment_Statement | |
2671 | and then Is_Entity_Name (Name (Parnt)) | |
9dfe12ae | 2672 | and then Range_Checks_Suppressed (Entity (Name (Parnt))) |
ee6ba406 | 2673 | then |
2674 | return; | |
2675 | end if; | |
2676 | end if; | |
2677 | end if; | |
2678 | ||
9dfe12ae | 2679 | -- Do not set range checks if they are killed |
2680 | ||
2681 | if Nkind (Expr) = N_Unchecked_Type_Conversion | |
2682 | and then Kill_Range_Check (Expr) | |
2683 | then | |
2684 | return; | |
2685 | end if; | |
2686 | ||
2687 | -- Do not set range checks for any values from System.Scalar_Values | |
2688 | -- since the whole idea of such values is to avoid checking them! | |
2689 | ||
2690 | if Is_Entity_Name (Expr) | |
2691 | and then Is_RTU (Scope (Entity (Expr)), System_Scalar_Values) | |
2692 | then | |
2693 | return; | |
2694 | end if; | |
2695 | ||
ee6ba406 | 2696 | -- Now see if we need a check |
2697 | ||
2698 | if No (Source_Typ) then | |
2699 | S_Typ := Etype (Expr); | |
2700 | else | |
2701 | S_Typ := Source_Typ; | |
2702 | end if; | |
2703 | ||
2704 | if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then | |
2705 | return; | |
2706 | end if; | |
2707 | ||
2708 | Is_Unconstrained_Subscr_Ref := | |
2709 | Is_Subscr_Ref and then not Is_Constrained (Arr_Typ); | |
2710 | ||
b40670e1 | 2711 | -- Special checks for floating-point type |
ee6ba406 | 2712 | |
b40670e1 | 2713 | if Is_Floating_Point_Type (S_Typ) then |
2714 | ||
2715 | -- Always do a range check if the source type includes infinities and | |
2716 | -- the target type does not include infinities. We do not do this if | |
2717 | -- range checks are killed. | |
2718 | ||
2719 | if Has_Infinities (S_Typ) | |
2720 | and then not Has_Infinities (Target_Typ) | |
2721 | then | |
2722 | Enable_Range_Check (Expr); | |
2723 | ||
2724 | -- Always do a range check for operators if option set | |
2725 | ||
2726 | elsif Check_Float_Overflow and then Nkind (Expr) in N_Op then | |
2727 | Enable_Range_Check (Expr); | |
2728 | end if; | |
ee6ba406 | 2729 | end if; |
2730 | ||
feff2f05 | 2731 | -- Return if we know expression is definitely in the range of the target |
2732 | -- type as determined by Determine_Range. Right now we only do this for | |
2733 | -- discrete types, and not fixed-point or floating-point types. | |
ee6ba406 | 2734 | |
f2a06be9 | 2735 | -- The additional less-precise tests below catch these cases |
ee6ba406 | 2736 | |
feff2f05 | 2737 | -- Note: skip this if we are given a source_typ, since the point of |
2738 | -- supplying a Source_Typ is to stop us looking at the expression. | |
2739 | -- We could sharpen this test to be out parameters only ??? | |
ee6ba406 | 2740 | |
2741 | if Is_Discrete_Type (Target_Typ) | |
2742 | and then Is_Discrete_Type (Etype (Expr)) | |
2743 | and then not Is_Unconstrained_Subscr_Ref | |
2744 | and then No (Source_Typ) | |
2745 | then | |
2746 | declare | |
2747 | Tlo : constant Node_Id := Type_Low_Bound (Target_Typ); | |
2748 | Thi : constant Node_Id := Type_High_Bound (Target_Typ); | |
2749 | Lo : Uint; | |
2750 | Hi : Uint; | |
2751 | ||
2752 | begin | |
2753 | if Compile_Time_Known_Value (Tlo) | |
2754 | and then Compile_Time_Known_Value (Thi) | |
2755 | then | |
9dfe12ae | 2756 | declare |
2757 | Lov : constant Uint := Expr_Value (Tlo); | |
2758 | Hiv : constant Uint := Expr_Value (Thi); | |
ee6ba406 | 2759 | |
9dfe12ae | 2760 | begin |
2761 | -- If range is null, we for sure have a constraint error | |
2762 | -- (we don't even need to look at the value involved, | |
2763 | -- since all possible values will raise CE). | |
2764 | ||
2765 | if Lov > Hiv then | |
2766 | Bad_Value; | |
2767 | return; | |
2768 | end if; | |
2769 | ||
2770 | -- Otherwise determine range of value | |
2771 | ||
9c486805 | 2772 | Determine_Range (Expr, OK, Lo, Hi, Assume_Valid => True); |
9dfe12ae | 2773 | |
2774 | if OK then | |
2775 | ||
2776 | -- If definitely in range, all OK | |
ee6ba406 | 2777 | |
ee6ba406 | 2778 | if Lo >= Lov and then Hi <= Hiv then |
2779 | return; | |
2780 | ||
9dfe12ae | 2781 | -- If definitely not in range, warn |
2782 | ||
ee6ba406 | 2783 | elsif Lov > Hi or else Hiv < Lo then |
2784 | Bad_Value; | |
2785 | return; | |
9dfe12ae | 2786 | |
2787 | -- Otherwise we don't know | |
2788 | ||
2789 | else | |
2790 | null; | |
ee6ba406 | 2791 | end if; |
9dfe12ae | 2792 | end if; |
2793 | end; | |
ee6ba406 | 2794 | end if; |
2795 | end; | |
2796 | end if; | |
2797 | ||
2798 | Int_Real := | |
2799 | Is_Floating_Point_Type (S_Typ) | |
2800 | or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int); | |
2801 | ||
2802 | -- Check if we can determine at compile time whether Expr is in the | |
9dfe12ae | 2803 | -- range of the target type. Note that if S_Typ is within the bounds |
2804 | -- of Target_Typ then this must be the case. This check is meaningful | |
2805 | -- only if this is not a conversion between integer and real types. | |
ee6ba406 | 2806 | |
2807 | if not Is_Unconstrained_Subscr_Ref | |
b40670e1 | 2808 | and then Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ) |
ee6ba406 | 2809 | and then |
7a1dabb3 | 2810 | (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int) |
ee6ba406 | 2811 | or else |
9c486805 | 2812 | Is_In_Range (Expr, Target_Typ, |
2813 | Assume_Valid => True, | |
b40670e1 | 2814 | Fixed_Int => Fixed_Int, |
2815 | Int_Real => Int_Real)) | |
ee6ba406 | 2816 | then |
2817 | return; | |
2818 | ||
9c486805 | 2819 | elsif Is_Out_Of_Range (Expr, Target_Typ, |
2820 | Assume_Valid => True, | |
2821 | Fixed_Int => Fixed_Int, | |
2822 | Int_Real => Int_Real) | |
2823 | then | |
ee6ba406 | 2824 | Bad_Value; |
2825 | return; | |
2826 | ||
b40670e1 | 2827 | -- Floating-point case |
feff2f05 | 2828 | -- In the floating-point case, we only do range checks if the type is |
2829 | -- constrained. We definitely do NOT want range checks for unconstrained | |
2830 | -- types, since we want to have infinities | |
ee6ba406 | 2831 | |
9dfe12ae | 2832 | elsif Is_Floating_Point_Type (S_Typ) then |
b40670e1 | 2833 | |
2834 | -- Normally, we only do range checks if the type is constrained. We do | |
2835 | -- NOT want range checks for unconstrained types, since we want to have | |
2836 | -- infinities. Override this decision in Check_Float_Overflow mode. | |
2837 | ||
2838 | if Is_Constrained (S_Typ) or else Check_Float_Overflow then | |
9dfe12ae | 2839 | Enable_Range_Check (Expr); |
2840 | end if; | |
ee6ba406 | 2841 | |
9dfe12ae | 2842 | -- For all other cases we enable a range check unconditionally |
ee6ba406 | 2843 | |
2844 | else | |
2845 | Enable_Range_Check (Expr); | |
2846 | return; | |
2847 | end if; | |
ee6ba406 | 2848 | end Apply_Scalar_Range_Check; |
2849 | ||
2850 | ---------------------------------- | |
2851 | -- Apply_Selected_Length_Checks -- | |
2852 | ---------------------------------- | |
2853 | ||
2854 | procedure Apply_Selected_Length_Checks | |
2855 | (Ck_Node : Node_Id; | |
2856 | Target_Typ : Entity_Id; | |
2857 | Source_Typ : Entity_Id; | |
2858 | Do_Static : Boolean) | |
2859 | is | |
2860 | Cond : Node_Id; | |
2861 | R_Result : Check_Result; | |
2862 | R_Cno : Node_Id; | |
2863 | ||
2864 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
2865 | Checks_On : constant Boolean := | |
b6341c67 | 2866 | (not Index_Checks_Suppressed (Target_Typ)) |
2867 | or else (not Length_Checks_Suppressed (Target_Typ)); | |
ee6ba406 | 2868 | |
2869 | begin | |
6dbcfcd9 | 2870 | if not Full_Expander_Active then |
ee6ba406 | 2871 | return; |
2872 | end if; | |
2873 | ||
2874 | R_Result := | |
2875 | Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
2876 | ||
2877 | for J in 1 .. 2 loop | |
ee6ba406 | 2878 | R_Cno := R_Result (J); |
2879 | exit when No (R_Cno); | |
2880 | ||
2881 | -- A length check may mention an Itype which is attached to a | |
2882 | -- subsequent node. At the top level in a package this can cause | |
2883 | -- an order-of-elaboration problem, so we make sure that the itype | |
2884 | -- is referenced now. | |
2885 | ||
2886 | if Ekind (Current_Scope) = E_Package | |
2887 | and then Is_Compilation_Unit (Current_Scope) | |
2888 | then | |
2889 | Ensure_Defined (Target_Typ, Ck_Node); | |
2890 | ||
2891 | if Present (Source_Typ) then | |
2892 | Ensure_Defined (Source_Typ, Ck_Node); | |
2893 | ||
2894 | elsif Is_Itype (Etype (Ck_Node)) then | |
2895 | Ensure_Defined (Etype (Ck_Node), Ck_Node); | |
2896 | end if; | |
2897 | end if; | |
2898 | ||
feff2f05 | 2899 | -- If the item is a conditional raise of constraint error, then have |
2900 | -- a look at what check is being performed and ??? | |
ee6ba406 | 2901 | |
2902 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
2903 | and then Present (Condition (R_Cno)) | |
2904 | then | |
2905 | Cond := Condition (R_Cno); | |
2906 | ||
0577b0b1 | 2907 | -- Case where node does not now have a dynamic check |
ee6ba406 | 2908 | |
0577b0b1 | 2909 | if not Has_Dynamic_Length_Check (Ck_Node) then |
2910 | ||
2911 | -- If checks are on, just insert the check | |
2912 | ||
2913 | if Checks_On then | |
2914 | Insert_Action (Ck_Node, R_Cno); | |
2915 | ||
2916 | if not Do_Static then | |
2917 | Set_Has_Dynamic_Length_Check (Ck_Node); | |
2918 | end if; | |
2919 | ||
2920 | -- If checks are off, then analyze the length check after | |
2921 | -- temporarily attaching it to the tree in case the relevant | |
6fb3c314 | 2922 | -- condition can be evaluated at compile time. We still want a |
0577b0b1 | 2923 | -- compile time warning in this case. |
2924 | ||
2925 | else | |
2926 | Set_Parent (R_Cno, Ck_Node); | |
2927 | Analyze (R_Cno); | |
ee6ba406 | 2928 | end if; |
ee6ba406 | 2929 | end if; |
2930 | ||
2931 | -- Output a warning if the condition is known to be True | |
2932 | ||
2933 | if Is_Entity_Name (Cond) | |
2934 | and then Entity (Cond) = Standard_True | |
2935 | then | |
2936 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 2937 | (Ck_Node, "wrong length for array of}??", |
f15731c4 | 2938 | CE_Length_Check_Failed, |
ee6ba406 | 2939 | Ent => Target_Typ, |
2940 | Typ => Target_Typ); | |
2941 | ||
2942 | -- If we were only doing a static check, or if checks are not | |
2943 | -- on, then we want to delete the check, since it is not needed. | |
2944 | -- We do this by replacing the if statement by a null statement | |
2945 | ||
2946 | elsif Do_Static or else not Checks_On then | |
00c403ee | 2947 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 2948 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
2949 | end if; | |
2950 | ||
2951 | else | |
2952 | Install_Static_Check (R_Cno, Loc); | |
2953 | end if; | |
ee6ba406 | 2954 | end loop; |
ee6ba406 | 2955 | end Apply_Selected_Length_Checks; |
2956 | ||
2957 | --------------------------------- | |
2958 | -- Apply_Selected_Range_Checks -- | |
2959 | --------------------------------- | |
2960 | ||
2961 | procedure Apply_Selected_Range_Checks | |
2962 | (Ck_Node : Node_Id; | |
2963 | Target_Typ : Entity_Id; | |
2964 | Source_Typ : Entity_Id; | |
2965 | Do_Static : Boolean) | |
2966 | is | |
2967 | Cond : Node_Id; | |
2968 | R_Result : Check_Result; | |
2969 | R_Cno : Node_Id; | |
2970 | ||
2971 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
2972 | Checks_On : constant Boolean := | |
b6341c67 | 2973 | (not Index_Checks_Suppressed (Target_Typ)) |
2974 | or else (not Range_Checks_Suppressed (Target_Typ)); | |
ee6ba406 | 2975 | |
2976 | begin | |
6dbcfcd9 | 2977 | if not Full_Expander_Active or else not Checks_On then |
ee6ba406 | 2978 | return; |
2979 | end if; | |
2980 | ||
2981 | R_Result := | |
2982 | Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); | |
2983 | ||
2984 | for J in 1 .. 2 loop | |
2985 | ||
2986 | R_Cno := R_Result (J); | |
2987 | exit when No (R_Cno); | |
2988 | ||
feff2f05 | 2989 | -- If the item is a conditional raise of constraint error, then have |
2990 | -- a look at what check is being performed and ??? | |
ee6ba406 | 2991 | |
2992 | if Nkind (R_Cno) = N_Raise_Constraint_Error | |
2993 | and then Present (Condition (R_Cno)) | |
2994 | then | |
2995 | Cond := Condition (R_Cno); | |
2996 | ||
2997 | if not Has_Dynamic_Range_Check (Ck_Node) then | |
2998 | Insert_Action (Ck_Node, R_Cno); | |
2999 | ||
3000 | if not Do_Static then | |
3001 | Set_Has_Dynamic_Range_Check (Ck_Node); | |
3002 | end if; | |
3003 | end if; | |
3004 | ||
3005 | -- Output a warning if the condition is known to be True | |
3006 | ||
3007 | if Is_Entity_Name (Cond) | |
3008 | and then Entity (Cond) = Standard_True | |
3009 | then | |
feff2f05 | 3010 | -- Since an N_Range is technically not an expression, we have |
3011 | -- to set one of the bounds to C_E and then just flag the | |
3012 | -- N_Range. The warning message will point to the lower bound | |
3013 | -- and complain about a range, which seems OK. | |
ee6ba406 | 3014 | |
3015 | if Nkind (Ck_Node) = N_Range then | |
3016 | Apply_Compile_Time_Constraint_Error | |
cb97ae5c | 3017 | (Low_Bound (Ck_Node), "static range out of bounds of}??", |
f15731c4 | 3018 | CE_Range_Check_Failed, |
ee6ba406 | 3019 | Ent => Target_Typ, |
3020 | Typ => Target_Typ); | |
3021 | ||
3022 | Set_Raises_Constraint_Error (Ck_Node); | |
3023 | ||
3024 | else | |
3025 | Apply_Compile_Time_Constraint_Error | |
3026 | (Ck_Node, "static value out of range of}?", | |
f15731c4 | 3027 | CE_Range_Check_Failed, |
ee6ba406 | 3028 | Ent => Target_Typ, |
3029 | Typ => Target_Typ); | |
3030 | end if; | |
3031 | ||
3032 | -- If we were only doing a static check, or if checks are not | |
3033 | -- on, then we want to delete the check, since it is not needed. | |
3034 | -- We do this by replacing the if statement by a null statement | |
3035 | ||
3036 | elsif Do_Static or else not Checks_On then | |
00c403ee | 3037 | Remove_Warning_Messages (R_Cno); |
ee6ba406 | 3038 | Rewrite (R_Cno, Make_Null_Statement (Loc)); |
3039 | end if; | |
3040 | ||
3041 | else | |
3042 | Install_Static_Check (R_Cno, Loc); | |
3043 | end if; | |
ee6ba406 | 3044 | end loop; |
ee6ba406 | 3045 | end Apply_Selected_Range_Checks; |
3046 | ||
3047 | ------------------------------- | |
3048 | -- Apply_Static_Length_Check -- | |
3049 | ------------------------------- | |
3050 | ||
3051 | procedure Apply_Static_Length_Check | |
3052 | (Expr : Node_Id; | |
3053 | Target_Typ : Entity_Id; | |
3054 | Source_Typ : Entity_Id := Empty) | |
3055 | is | |
3056 | begin | |
3057 | Apply_Selected_Length_Checks | |
3058 | (Expr, Target_Typ, Source_Typ, Do_Static => True); | |
3059 | end Apply_Static_Length_Check; | |
3060 | ||
3061 | ------------------------------------- | |
3062 | -- Apply_Subscript_Validity_Checks -- | |
3063 | ------------------------------------- | |
3064 | ||
3065 | procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is | |
3066 | Sub : Node_Id; | |
3067 | ||
3068 | begin | |
3069 | pragma Assert (Nkind (Expr) = N_Indexed_Component); | |
3070 | ||
3071 | -- Loop through subscripts | |
3072 | ||
3073 | Sub := First (Expressions (Expr)); | |
3074 | while Present (Sub) loop | |
3075 | ||
feff2f05 | 3076 | -- Check one subscript. Note that we do not worry about enumeration |
3077 | -- type with holes, since we will convert the value to a Pos value | |
3078 | -- for the subscript, and that convert will do the necessary validity | |
3079 | -- check. | |
ee6ba406 | 3080 | |
3081 | Ensure_Valid (Sub, Holes_OK => True); | |
3082 | ||
3083 | -- Move to next subscript | |
3084 | ||
3085 | Sub := Next (Sub); | |
3086 | end loop; | |
3087 | end Apply_Subscript_Validity_Checks; | |
3088 | ||
3089 | ---------------------------------- | |
3090 | -- Apply_Type_Conversion_Checks -- | |
3091 | ---------------------------------- | |
3092 | ||
3093 | procedure Apply_Type_Conversion_Checks (N : Node_Id) is | |
3094 | Target_Type : constant Entity_Id := Etype (N); | |
3095 | Target_Base : constant Entity_Id := Base_Type (Target_Type); | |
9dfe12ae | 3096 | Expr : constant Node_Id := Expression (N); |
f4532fe1 | 3097 | |
3098 | Expr_Type : constant Entity_Id := Underlying_Type (Etype (Expr)); | |
141d591a | 3099 | -- Note: if Etype (Expr) is a private type without discriminants, its |
3100 | -- full view might have discriminants with defaults, so we need the | |
3101 | -- full view here to retrieve the constraints. | |
ee6ba406 | 3102 | |
3103 | begin | |
3104 | if Inside_A_Generic then | |
3105 | return; | |
3106 | ||
f15731c4 | 3107 | -- Skip these checks if serious errors detected, there are some nasty |
ee6ba406 | 3108 | -- situations of incomplete trees that blow things up. |
3109 | ||
f15731c4 | 3110 | elsif Serious_Errors_Detected > 0 then |
ee6ba406 | 3111 | return; |
3112 | ||
feff2f05 | 3113 | -- Scalar type conversions of the form Target_Type (Expr) require a |
3114 | -- range check if we cannot be sure that Expr is in the base type of | |
3115 | -- Target_Typ and also that Expr is in the range of Target_Typ. These | |
3116 | -- are not quite the same condition from an implementation point of | |
3117 | -- view, but clearly the second includes the first. | |
ee6ba406 | 3118 | |
3119 | elsif Is_Scalar_Type (Target_Type) then | |
3120 | declare | |
3121 | Conv_OK : constant Boolean := Conversion_OK (N); | |
feff2f05 | 3122 | -- If the Conversion_OK flag on the type conversion is set and no |
3123 | -- floating point type is involved in the type conversion then | |
3124 | -- fixed point values must be read as integral values. | |
ee6ba406 | 3125 | |
5329ca64 | 3126 | Float_To_Int : constant Boolean := |
b6341c67 | 3127 | Is_Floating_Point_Type (Expr_Type) |
3128 | and then Is_Integer_Type (Target_Type); | |
5329ca64 | 3129 | |
ee6ba406 | 3130 | begin |
ee6ba406 | 3131 | if not Overflow_Checks_Suppressed (Target_Base) |
0df9d43f | 3132 | and then not Overflow_Checks_Suppressed (Target_Type) |
e254d721 | 3133 | and then not |
7a1dabb3 | 3134 | In_Subrange_Of (Expr_Type, Target_Base, Fixed_Int => Conv_OK) |
5329ca64 | 3135 | and then not Float_To_Int |
ee6ba406 | 3136 | then |
00c403ee | 3137 | Activate_Overflow_Check (N); |
ee6ba406 | 3138 | end if; |
3139 | ||
3140 | if not Range_Checks_Suppressed (Target_Type) | |
3141 | and then not Range_Checks_Suppressed (Expr_Type) | |
3142 | then | |
5329ca64 | 3143 | if Float_To_Int then |
3144 | Apply_Float_Conversion_Check (Expr, Target_Type); | |
3145 | else | |
3146 | Apply_Scalar_Range_Check | |
3147 | (Expr, Target_Type, Fixed_Int => Conv_OK); | |
798afddc | 3148 | |
3149 | -- If the target type has predicates, we need to indicate | |
3150 | -- the need for a check, even if Determine_Range finds | |
3151 | -- that the value is within bounds. This may be the case | |
3152 | -- e.g for a division with a constant denominator. | |
3153 | ||
3154 | if Has_Predicates (Target_Type) then | |
3155 | Enable_Range_Check (Expr); | |
3156 | end if; | |
5329ca64 | 3157 | end if; |
ee6ba406 | 3158 | end if; |
3159 | end; | |
3160 | ||
3161 | elsif Comes_From_Source (N) | |
f40f9731 | 3162 | and then not Discriminant_Checks_Suppressed (Target_Type) |
ee6ba406 | 3163 | and then Is_Record_Type (Target_Type) |
3164 | and then Is_Derived_Type (Target_Type) | |
3165 | and then not Is_Tagged_Type (Target_Type) | |
3166 | and then not Is_Constrained (Target_Type) | |
9dfe12ae | 3167 | and then Present (Stored_Constraint (Target_Type)) |
ee6ba406 | 3168 | then |
141d591a | 3169 | -- An unconstrained derived type may have inherited discriminant. |
9dfe12ae | 3170 | -- Build an actual discriminant constraint list using the stored |
ee6ba406 | 3171 | -- constraint, to verify that the expression of the parent type |
3172 | -- satisfies the constraints imposed by the (unconstrained!) | |
3173 | -- derived type. This applies to value conversions, not to view | |
3174 | -- conversions of tagged types. | |
3175 | ||
3176 | declare | |
9dfe12ae | 3177 | Loc : constant Source_Ptr := Sloc (N); |
3178 | Cond : Node_Id; | |
3179 | Constraint : Elmt_Id; | |
3180 | Discr_Value : Node_Id; | |
3181 | Discr : Entity_Id; | |
3182 | ||
3183 | New_Constraints : constant Elist_Id := New_Elmt_List; | |
3184 | Old_Constraints : constant Elist_Id := | |
b6341c67 | 3185 | Discriminant_Constraint (Expr_Type); |
ee6ba406 | 3186 | |
3187 | begin | |
9dfe12ae | 3188 | Constraint := First_Elmt (Stored_Constraint (Target_Type)); |
ee6ba406 | 3189 | while Present (Constraint) loop |
3190 | Discr_Value := Node (Constraint); | |
3191 | ||
3192 | if Is_Entity_Name (Discr_Value) | |
3193 | and then Ekind (Entity (Discr_Value)) = E_Discriminant | |
3194 | then | |
3195 | Discr := Corresponding_Discriminant (Entity (Discr_Value)); | |
3196 | ||
3197 | if Present (Discr) | |
3198 | and then Scope (Discr) = Base_Type (Expr_Type) | |
3199 | then | |
3200 | -- Parent is constrained by new discriminant. Obtain | |
feff2f05 | 3201 | -- Value of original discriminant in expression. If the |
3202 | -- new discriminant has been used to constrain more than | |
3203 | -- one of the stored discriminants, this will provide the | |
3204 | -- required consistency check. | |
ee6ba406 | 3205 | |
55868293 | 3206 | Append_Elmt |
3207 | (Make_Selected_Component (Loc, | |
3208 | Prefix => | |
9dfe12ae | 3209 | Duplicate_Subexpr_No_Checks |
3210 | (Expr, Name_Req => True), | |
ee6ba406 | 3211 | Selector_Name => |
3212 | Make_Identifier (Loc, Chars (Discr))), | |
55868293 | 3213 | New_Constraints); |
ee6ba406 | 3214 | |
3215 | else | |
3216 | -- Discriminant of more remote ancestor ??? | |
3217 | ||
3218 | return; | |
3219 | end if; | |
3220 | ||
feff2f05 | 3221 | -- Derived type definition has an explicit value for this |
3222 | -- stored discriminant. | |
ee6ba406 | 3223 | |
3224 | else | |
3225 | Append_Elmt | |
9dfe12ae | 3226 | (Duplicate_Subexpr_No_Checks (Discr_Value), |
3227 | New_Constraints); | |
ee6ba406 | 3228 | end if; |
3229 | ||
3230 | Next_Elmt (Constraint); | |
3231 | end loop; | |
3232 | ||
3233 | -- Use the unconstrained expression type to retrieve the | |
3234 | -- discriminants of the parent, and apply momentarily the | |
3235 | -- discriminant constraint synthesized above. | |
3236 | ||
3237 | Set_Discriminant_Constraint (Expr_Type, New_Constraints); | |
3238 | Cond := Build_Discriminant_Checks (Expr, Expr_Type); | |
3239 | Set_Discriminant_Constraint (Expr_Type, Old_Constraints); | |
3240 | ||
3241 | Insert_Action (N, | |
f15731c4 | 3242 | Make_Raise_Constraint_Error (Loc, |
3243 | Condition => Cond, | |
3244 | Reason => CE_Discriminant_Check_Failed)); | |
ee6ba406 | 3245 | end; |
3246 | ||
175a6969 | 3247 | -- For arrays, checks are set now, but conversions are applied during |
3248 | -- expansion, to take into accounts changes of representation. The | |
3249 | -- checks become range checks on the base type or length checks on the | |
3250 | -- subtype, depending on whether the target type is unconstrained or | |
8e802312 | 3251 | -- constrained. Note that the range check is put on the expression of a |
3252 | -- type conversion, while the length check is put on the type conversion | |
3253 | -- itself. | |
175a6969 | 3254 | |
3255 | elsif Is_Array_Type (Target_Type) then | |
3256 | if Is_Constrained (Target_Type) then | |
3257 | Set_Do_Length_Check (N); | |
3258 | else | |
3259 | Set_Do_Range_Check (Expr); | |
3260 | end if; | |
ee6ba406 | 3261 | end if; |
ee6ba406 | 3262 | end Apply_Type_Conversion_Checks; |
3263 | ||
3264 | ---------------------------------------------- | |
3265 | -- Apply_Universal_Integer_Attribute_Checks -- | |
3266 | ---------------------------------------------- | |
3267 | ||
3268 | procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is | |
3269 | Loc : constant Source_Ptr := Sloc (N); | |
3270 | Typ : constant Entity_Id := Etype (N); | |
3271 | ||
3272 | begin | |
3273 | if Inside_A_Generic then | |
3274 | return; | |
3275 | ||
3276 | -- Nothing to do if checks are suppressed | |
3277 | ||
3278 | elsif Range_Checks_Suppressed (Typ) | |
3279 | and then Overflow_Checks_Suppressed (Typ) | |
3280 | then | |
3281 | return; | |
3282 | ||
3283 | -- Nothing to do if the attribute does not come from source. The | |
3284 | -- internal attributes we generate of this type do not need checks, | |
3285 | -- and furthermore the attempt to check them causes some circular | |
3286 | -- elaboration orders when dealing with packed types. | |
3287 | ||
3288 | elsif not Comes_From_Source (N) then | |
3289 | return; | |
3290 | ||
9dfe12ae | 3291 | -- If the prefix is a selected component that depends on a discriminant |
3292 | -- the check may improperly expose a discriminant instead of using | |
3293 | -- the bounds of the object itself. Set the type of the attribute to | |
3294 | -- the base type of the context, so that a check will be imposed when | |
3295 | -- needed (e.g. if the node appears as an index). | |
3296 | ||
3297 | elsif Nkind (Prefix (N)) = N_Selected_Component | |
3298 | and then Ekind (Typ) = E_Signed_Integer_Subtype | |
3299 | and then Depends_On_Discriminant (Scalar_Range (Typ)) | |
3300 | then | |
3301 | Set_Etype (N, Base_Type (Typ)); | |
3302 | ||
feff2f05 | 3303 | -- Otherwise, replace the attribute node with a type conversion node |
3304 | -- whose expression is the attribute, retyped to universal integer, and | |
3305 | -- whose subtype mark is the target type. The call to analyze this | |
3306 | -- conversion will set range and overflow checks as required for proper | |
3307 | -- detection of an out of range value. | |
ee6ba406 | 3308 | |
3309 | else | |
3310 | Set_Etype (N, Universal_Integer); | |
3311 | Set_Analyzed (N, True); | |
3312 | ||
3313 | Rewrite (N, | |
3314 | Make_Type_Conversion (Loc, | |
3315 | Subtype_Mark => New_Occurrence_Of (Typ, Loc), | |
3316 | Expression => Relocate_Node (N))); | |
3317 | ||
3318 | Analyze_And_Resolve (N, Typ); | |
3319 | return; | |
3320 | end if; | |
ee6ba406 | 3321 | end Apply_Universal_Integer_Attribute_Checks; |
3322 | ||
07c191b0 | 3323 | ------------------------------------- |
3324 | -- Atomic_Synchronization_Disabled -- | |
3325 | ------------------------------------- | |
3326 | ||
3327 | -- Note: internally Disable/Enable_Atomic_Synchronization is implemented | |
3328 | -- using a bogus check called Atomic_Synchronization. This is to make it | |
3329 | -- more convenient to get exactly the same semantics as [Un]Suppress. | |
3330 | ||
3331 | function Atomic_Synchronization_Disabled (E : Entity_Id) return Boolean is | |
3332 | begin | |
b444f81d | 3333 | -- If debug flag d.e is set, always return False, i.e. all atomic sync |
3334 | -- looks enabled, since it is never disabled. | |
3335 | ||
3336 | if Debug_Flag_Dot_E then | |
3337 | return False; | |
3338 | ||
3339 | -- If debug flag d.d is set then always return True, i.e. all atomic | |
3340 | -- sync looks disabled, since it always tests True. | |
3341 | ||
3342 | elsif Debug_Flag_Dot_D then | |
3343 | return True; | |
3344 | ||
3345 | -- If entity present, then check result for that entity | |
3346 | ||
3347 | elsif Present (E) and then Checks_May_Be_Suppressed (E) then | |
07c191b0 | 3348 | return Is_Check_Suppressed (E, Atomic_Synchronization); |
b444f81d | 3349 | |
3350 | -- Otherwise result depends on current scope setting | |
3351 | ||
07c191b0 | 3352 | else |
fafc6b97 | 3353 | return Scope_Suppress.Suppress (Atomic_Synchronization); |
07c191b0 | 3354 | end if; |
3355 | end Atomic_Synchronization_Disabled; | |
3356 | ||
ee6ba406 | 3357 | ------------------------------- |
3358 | -- Build_Discriminant_Checks -- | |
3359 | ------------------------------- | |
3360 | ||
3361 | function Build_Discriminant_Checks | |
3362 | (N : Node_Id; | |
314a23b6 | 3363 | T_Typ : Entity_Id) return Node_Id |
ee6ba406 | 3364 | is |
3365 | Loc : constant Source_Ptr := Sloc (N); | |
3366 | Cond : Node_Id; | |
3367 | Disc : Elmt_Id; | |
3368 | Disc_Ent : Entity_Id; | |
9dfe12ae | 3369 | Dref : Node_Id; |
ee6ba406 | 3370 | Dval : Node_Id; |
3371 | ||
84d0d4a5 | 3372 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id; |
3373 | ||
3374 | ---------------------------------- | |
3375 | -- Aggregate_Discriminant_Value -- | |
3376 | ---------------------------------- | |
3377 | ||
3378 | function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id is | |
3379 | Assoc : Node_Id; | |
3380 | ||
3381 | begin | |
feff2f05 | 3382 | -- The aggregate has been normalized with named associations. We use |
3383 | -- the Chars field to locate the discriminant to take into account | |
3384 | -- discriminants in derived types, which carry the same name as those | |
3385 | -- in the parent. | |
84d0d4a5 | 3386 | |
3387 | Assoc := First (Component_Associations (N)); | |
3388 | while Present (Assoc) loop | |
3389 | if Chars (First (Choices (Assoc))) = Chars (Disc) then | |
3390 | return Expression (Assoc); | |
3391 | else | |
3392 | Next (Assoc); | |
3393 | end if; | |
3394 | end loop; | |
3395 | ||
3396 | -- Discriminant must have been found in the loop above | |
3397 | ||
3398 | raise Program_Error; | |
3399 | end Aggregate_Discriminant_Val; | |
3400 | ||
3401 | -- Start of processing for Build_Discriminant_Checks | |
3402 | ||
ee6ba406 | 3403 | begin |
84d0d4a5 | 3404 | -- Loop through discriminants evolving the condition |
3405 | ||
ee6ba406 | 3406 | Cond := Empty; |
3407 | Disc := First_Elmt (Discriminant_Constraint (T_Typ)); | |
3408 | ||
9dfe12ae | 3409 | -- For a fully private type, use the discriminants of the parent type |
ee6ba406 | 3410 | |
3411 | if Is_Private_Type (T_Typ) | |
3412 | and then No (Full_View (T_Typ)) | |
3413 | then | |
3414 | Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ))); | |
3415 | else | |
3416 | Disc_Ent := First_Discriminant (T_Typ); | |
3417 | end if; | |
3418 | ||
3419 | while Present (Disc) loop | |
ee6ba406 | 3420 | Dval := Node (Disc); |
3421 | ||
3422 | if Nkind (Dval) = N_Identifier | |
3423 | and then Ekind (Entity (Dval)) = E_Discriminant | |
3424 | then | |
3425 | Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc); | |
3426 | else | |
9dfe12ae | 3427 | Dval := Duplicate_Subexpr_No_Checks (Dval); |
ee6ba406 | 3428 | end if; |
3429 | ||
00f91aef | 3430 | -- If we have an Unchecked_Union node, we can infer the discriminants |
3431 | -- of the node. | |
9dfe12ae | 3432 | |
00f91aef | 3433 | if Is_Unchecked_Union (Base_Type (T_Typ)) then |
3434 | Dref := New_Copy ( | |
3435 | Get_Discriminant_Value ( | |
3436 | First_Discriminant (T_Typ), | |
3437 | T_Typ, | |
3438 | Stored_Constraint (T_Typ))); | |
3439 | ||
84d0d4a5 | 3440 | elsif Nkind (N) = N_Aggregate then |
3441 | Dref := | |
3442 | Duplicate_Subexpr_No_Checks | |
3443 | (Aggregate_Discriminant_Val (Disc_Ent)); | |
3444 | ||
00f91aef | 3445 | else |
3446 | Dref := | |
3447 | Make_Selected_Component (Loc, | |
3448 | Prefix => | |
3449 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), | |
3450 | Selector_Name => | |
3451 | Make_Identifier (Loc, Chars (Disc_Ent))); | |
3452 | ||
3453 | Set_Is_In_Discriminant_Check (Dref); | |
3454 | end if; | |
9dfe12ae | 3455 | |
ee6ba406 | 3456 | Evolve_Or_Else (Cond, |
3457 | Make_Op_Ne (Loc, | |
9dfe12ae | 3458 | Left_Opnd => Dref, |
ee6ba406 | 3459 | Right_Opnd => Dval)); |
3460 | ||
3461 | Next_Elmt (Disc); | |
3462 | Next_Discriminant (Disc_Ent); | |
3463 | end loop; | |
3464 | ||
3465 | return Cond; | |
3466 | end Build_Discriminant_Checks; | |
3467 | ||
13dbf220 | 3468 | ------------------ |
3469 | -- Check_Needed -- | |
3470 | ------------------ | |
3471 | ||
3472 | function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean is | |
3473 | N : Node_Id; | |
3474 | P : Node_Id; | |
3475 | K : Node_Kind; | |
3476 | L : Node_Id; | |
3477 | R : Node_Id; | |
3478 | ||
3479 | begin | |
3480 | -- Always check if not simple entity | |
3481 | ||
3482 | if Nkind (Nod) not in N_Has_Entity | |
3483 | or else not Comes_From_Source (Nod) | |
3484 | then | |
3485 | return True; | |
3486 | end if; | |
3487 | ||
3488 | -- Look up tree for short circuit | |
3489 | ||
3490 | N := Nod; | |
3491 | loop | |
3492 | P := Parent (N); | |
3493 | K := Nkind (P); | |
3494 | ||
7b17e51b | 3495 | -- Done if out of subexpression (note that we allow generated stuff |
3496 | -- such as itype declarations in this context, to keep the loop going | |
3497 | -- since we may well have generated such stuff in complex situations. | |
3498 | -- Also done if no parent (probably an error condition, but no point | |
3499 | -- in behaving nasty if we find it!) | |
3500 | ||
3501 | if No (P) | |
3502 | or else (K not in N_Subexpr and then Comes_From_Source (P)) | |
3503 | then | |
13dbf220 | 3504 | return True; |
3505 | ||
7b17e51b | 3506 | -- Or/Or Else case, where test is part of the right operand, or is |
3507 | -- part of one of the actions associated with the right operand, and | |
3508 | -- the left operand is an equality test. | |
13dbf220 | 3509 | |
7b17e51b | 3510 | elsif K = N_Op_Or then |
13dbf220 | 3511 | exit when N = Right_Opnd (P) |
3512 | and then Nkind (Left_Opnd (P)) = N_Op_Eq; | |
3513 | ||
7b17e51b | 3514 | elsif K = N_Or_Else then |
3515 | exit when (N = Right_Opnd (P) | |
3516 | or else | |
3517 | (Is_List_Member (N) | |
3518 | and then List_Containing (N) = Actions (P))) | |
3519 | and then Nkind (Left_Opnd (P)) = N_Op_Eq; | |
13dbf220 | 3520 | |
7b17e51b | 3521 | -- Similar test for the And/And then case, where the left operand |
3522 | -- is an inequality test. | |
3523 | ||
3524 | elsif K = N_Op_And then | |
13dbf220 | 3525 | exit when N = Right_Opnd (P) |
38f5559f | 3526 | and then Nkind (Left_Opnd (P)) = N_Op_Ne; |
7b17e51b | 3527 | |
3528 | elsif K = N_And_Then then | |
3529 | exit when (N = Right_Opnd (P) | |
3530 | or else | |
3531 | (Is_List_Member (N) | |
3532 | and then List_Containing (N) = Actions (P))) | |
3533 | and then Nkind (Left_Opnd (P)) = N_Op_Ne; | |
13dbf220 | 3534 | end if; |
3535 | ||
3536 | N := P; | |
3537 | end loop; | |
3538 | ||
3539 | -- If we fall through the loop, then we have a conditional with an | |
3540 | -- appropriate test as its left operand. So test further. | |
3541 | ||
3542 | L := Left_Opnd (P); | |
13dbf220 | 3543 | R := Right_Opnd (L); |
3544 | L := Left_Opnd (L); | |
3545 | ||
3546 | -- Left operand of test must match original variable | |
3547 | ||
3548 | if Nkind (L) not in N_Has_Entity | |
3549 | or else Entity (L) /= Entity (Nod) | |
3550 | then | |
3551 | return True; | |
3552 | end if; | |
3553 | ||
2af58f67 | 3554 | -- Right operand of test must be key value (zero or null) |
13dbf220 | 3555 | |
3556 | case Check is | |
3557 | when Access_Check => | |
2af58f67 | 3558 | if not Known_Null (R) then |
13dbf220 | 3559 | return True; |
3560 | end if; | |
3561 | ||
3562 | when Division_Check => | |
3563 | if not Compile_Time_Known_Value (R) | |
3564 | or else Expr_Value (R) /= Uint_0 | |
3565 | then | |
3566 | return True; | |
3567 | end if; | |
2af58f67 | 3568 | |
3569 | when others => | |
3570 | raise Program_Error; | |
13dbf220 | 3571 | end case; |
3572 | ||
3573 | -- Here we have the optimizable case, warn if not short-circuited | |
3574 | ||
3575 | if K = N_Op_And or else K = N_Op_Or then | |
3576 | case Check is | |
3577 | when Access_Check => | |
3578 | Error_Msg_N | |
cb97ae5c | 3579 | ("Constraint_Error may be raised (access check)??", |
13dbf220 | 3580 | Parent (Nod)); |
3581 | when Division_Check => | |
3582 | Error_Msg_N | |
cb97ae5c | 3583 | ("Constraint_Error may be raised (zero divide)??", |
13dbf220 | 3584 | Parent (Nod)); |
2af58f67 | 3585 | |
3586 | when others => | |
3587 | raise Program_Error; | |
13dbf220 | 3588 | end case; |
3589 | ||
3590 | if K = N_Op_And then | |
e977c0cf | 3591 | Error_Msg_N -- CODEFIX |
cb97ae5c | 3592 | ("use `AND THEN` instead of AND??", P); |
13dbf220 | 3593 | else |
e977c0cf | 3594 | Error_Msg_N -- CODEFIX |
cb97ae5c | 3595 | ("use `OR ELSE` instead of OR??", P); |
13dbf220 | 3596 | end if; |
3597 | ||
6fb3c314 | 3598 | -- If not short-circuited, we need the check |
13dbf220 | 3599 | |
3600 | return True; | |
3601 | ||
3602 | -- If short-circuited, we can omit the check | |
3603 | ||
3604 | else | |
3605 | return False; | |
3606 | end if; | |
3607 | end Check_Needed; | |
3608 | ||
ee6ba406 | 3609 | ----------------------------------- |
3610 | -- Check_Valid_Lvalue_Subscripts -- | |
3611 | ----------------------------------- | |
3612 | ||
3613 | procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is | |
3614 | begin | |
3615 | -- Skip this if range checks are suppressed | |
3616 | ||
3617 | if Range_Checks_Suppressed (Etype (Expr)) then | |
3618 | return; | |
3619 | ||
feff2f05 | 3620 | -- Only do this check for expressions that come from source. We assume |
3621 | -- that expander generated assignments explicitly include any necessary | |
3622 | -- checks. Note that this is not just an optimization, it avoids | |
3623 | -- infinite recursions! | |
ee6ba406 | 3624 | |
3625 | elsif not Comes_From_Source (Expr) then | |
3626 | return; | |
3627 | ||
3628 | -- For a selected component, check the prefix | |
3629 | ||
3630 | elsif Nkind (Expr) = N_Selected_Component then | |
3631 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
3632 | return; | |
3633 | ||
3634 | -- Case of indexed component | |
3635 | ||
3636 | elsif Nkind (Expr) = N_Indexed_Component then | |
3637 | Apply_Subscript_Validity_Checks (Expr); | |
3638 | ||
feff2f05 | 3639 | -- Prefix may itself be or contain an indexed component, and these |
3640 | -- subscripts need checking as well. | |
ee6ba406 | 3641 | |
3642 | Check_Valid_Lvalue_Subscripts (Prefix (Expr)); | |
3643 | end if; | |
3644 | end Check_Valid_Lvalue_Subscripts; | |
3645 | ||
fa7497e8 | 3646 | ---------------------------------- |
3647 | -- Null_Exclusion_Static_Checks -- | |
3648 | ---------------------------------- | |
3649 | ||
3650 | procedure Null_Exclusion_Static_Checks (N : Node_Id) is | |
0577b0b1 | 3651 | Error_Node : Node_Id; |
3652 | Expr : Node_Id; | |
3653 | Has_Null : constant Boolean := Has_Null_Exclusion (N); | |
3654 | K : constant Node_Kind := Nkind (N); | |
3655 | Typ : Entity_Id; | |
fa7497e8 | 3656 | |
13dbf220 | 3657 | begin |
0577b0b1 | 3658 | pragma Assert |
3659 | (K = N_Component_Declaration | |
3660 | or else K = N_Discriminant_Specification | |
3661 | or else K = N_Function_Specification | |
3662 | or else K = N_Object_Declaration | |
3663 | or else K = N_Parameter_Specification); | |
3664 | ||
3665 | if K = N_Function_Specification then | |
3666 | Typ := Etype (Defining_Entity (N)); | |
3667 | else | |
3668 | Typ := Etype (Defining_Identifier (N)); | |
3669 | end if; | |
fa7497e8 | 3670 | |
13dbf220 | 3671 | case K is |
13dbf220 | 3672 | when N_Component_Declaration => |
3673 | if Present (Access_Definition (Component_Definition (N))) then | |
0577b0b1 | 3674 | Error_Node := Component_Definition (N); |
13dbf220 | 3675 | else |
0577b0b1 | 3676 | Error_Node := Subtype_Indication (Component_Definition (N)); |
13dbf220 | 3677 | end if; |
5329ca64 | 3678 | |
0577b0b1 | 3679 | when N_Discriminant_Specification => |
3680 | Error_Node := Discriminant_Type (N); | |
3681 | ||
3682 | when N_Function_Specification => | |
3683 | Error_Node := Result_Definition (N); | |
3684 | ||
3685 | when N_Object_Declaration => | |
3686 | Error_Node := Object_Definition (N); | |
3687 | ||
3688 | when N_Parameter_Specification => | |
3689 | Error_Node := Parameter_Type (N); | |
3690 | ||
13dbf220 | 3691 | when others => |
3692 | raise Program_Error; | |
3693 | end case; | |
5329ca64 | 3694 | |
0577b0b1 | 3695 | if Has_Null then |
5329ca64 | 3696 | |
0577b0b1 | 3697 | -- Enforce legality rule 3.10 (13): A null exclusion can only be |
3698 | -- applied to an access [sub]type. | |
5329ca64 | 3699 | |
0577b0b1 | 3700 | if not Is_Access_Type (Typ) then |
503f7fd3 | 3701 | Error_Msg_N |
00c403ee | 3702 | ("`NOT NULL` allowed only for an access type", Error_Node); |
5329ca64 | 3703 | |
feff2f05 | 3704 | -- Enforce legality rule RM 3.10(14/1): A null exclusion can only |
0577b0b1 | 3705 | -- be applied to a [sub]type that does not exclude null already. |
3706 | ||
3707 | elsif Can_Never_Be_Null (Typ) | |
d16989f1 | 3708 | and then Comes_From_Source (Typ) |
0577b0b1 | 3709 | then |
503f7fd3 | 3710 | Error_Msg_NE |
00c403ee | 3711 | ("`NOT NULL` not allowed (& already excludes null)", |
3712 | Error_Node, Typ); | |
0577b0b1 | 3713 | end if; |
13dbf220 | 3714 | end if; |
5329ca64 | 3715 | |
cc60bd16 | 3716 | -- Check that null-excluding objects are always initialized, except for |
3717 | -- deferred constants, for which the expression will appear in the full | |
3718 | -- declaration. | |
13dbf220 | 3719 | |
3720 | if K = N_Object_Declaration | |
84d0d4a5 | 3721 | and then No (Expression (N)) |
cc60bd16 | 3722 | and then not Constant_Present (N) |
feff2f05 | 3723 | and then not No_Initialization (N) |
13dbf220 | 3724 | then |
feff2f05 | 3725 | -- Add an expression that assigns null. This node is needed by |
3726 | -- Apply_Compile_Time_Constraint_Error, which will replace this with | |
3727 | -- a Constraint_Error node. | |
13dbf220 | 3728 | |
3729 | Set_Expression (N, Make_Null (Sloc (N))); | |
3730 | Set_Etype (Expression (N), Etype (Defining_Identifier (N))); | |
5329ca64 | 3731 | |
13dbf220 | 3732 | Apply_Compile_Time_Constraint_Error |
3733 | (N => Expression (N), | |
cb97ae5c | 3734 | Msg => |
3735 | "(Ada 2005) null-excluding objects must be initialized??", | |
13dbf220 | 3736 | Reason => CE_Null_Not_Allowed); |
3737 | end if; | |
5329ca64 | 3738 | |
cc60bd16 | 3739 | -- Check that a null-excluding component, formal or object is not being |
3740 | -- assigned a null value. Otherwise generate a warning message and | |
2c145f84 | 3741 | -- replace Expression (N) by an N_Constraint_Error node. |
13dbf220 | 3742 | |
0577b0b1 | 3743 | if K /= N_Function_Specification then |
3744 | Expr := Expression (N); | |
5329ca64 | 3745 | |
2af58f67 | 3746 | if Present (Expr) and then Known_Null (Expr) then |
13dbf220 | 3747 | case K is |
0577b0b1 | 3748 | when N_Component_Declaration | |
3749 | N_Discriminant_Specification => | |
7189d17f | 3750 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 3751 | (N => Expr, |
2af58f67 | 3752 | Msg => "(Ada 2005) null not allowed " & |
cb97ae5c | 3753 | "in null-excluding components??", |
0577b0b1 | 3754 | Reason => CE_Null_Not_Allowed); |
5329ca64 | 3755 | |
0577b0b1 | 3756 | when N_Object_Declaration => |
7189d17f | 3757 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 3758 | (N => Expr, |
2af58f67 | 3759 | Msg => "(Ada 2005) null not allowed " & |
0577b0b1 | 3760 | "in null-excluding objects?", |
3761 | Reason => CE_Null_Not_Allowed); | |
5329ca64 | 3762 | |
0577b0b1 | 3763 | when N_Parameter_Specification => |
7189d17f | 3764 | Apply_Compile_Time_Constraint_Error |
0577b0b1 | 3765 | (N => Expr, |
2af58f67 | 3766 | Msg => "(Ada 2005) null not allowed " & |
cb97ae5c | 3767 | "in null-excluding formals??", |
0577b0b1 | 3768 | Reason => CE_Null_Not_Allowed); |
13dbf220 | 3769 | |
3770 | when others => | |
3771 | null; | |
5329ca64 | 3772 | end case; |
3773 | end if; | |
0577b0b1 | 3774 | end if; |
fa7497e8 | 3775 | end Null_Exclusion_Static_Checks; |
3776 | ||
9dfe12ae | 3777 | ---------------------------------- |
3778 | -- Conditional_Statements_Begin -- | |
3779 | ---------------------------------- | |
3780 | ||
3781 | procedure Conditional_Statements_Begin is | |
3782 | begin | |
3783 | Saved_Checks_TOS := Saved_Checks_TOS + 1; | |
3784 | ||
feff2f05 | 3785 | -- If stack overflows, kill all checks, that way we know to simply reset |
3786 | -- the number of saved checks to zero on return. This should never occur | |
3787 | -- in practice. | |
9dfe12ae | 3788 | |
3789 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
3790 | Kill_All_Checks; | |
3791 | ||
feff2f05 | 3792 | -- In the normal case, we just make a new stack entry saving the current |
3793 | -- number of saved checks for a later restore. | |
9dfe12ae | 3794 | |
3795 | else | |
3796 | Saved_Checks_Stack (Saved_Checks_TOS) := Num_Saved_Checks; | |
3797 | ||
3798 | if Debug_Flag_CC then | |
3799 | w ("Conditional_Statements_Begin: Num_Saved_Checks = ", | |
3800 | Num_Saved_Checks); | |
3801 | end if; | |
3802 | end if; | |
3803 | end Conditional_Statements_Begin; | |
3804 | ||
3805 | -------------------------------- | |
3806 | -- Conditional_Statements_End -- | |
3807 | -------------------------------- | |
3808 | ||
3809 | procedure Conditional_Statements_End is | |
3810 | begin | |
3811 | pragma Assert (Saved_Checks_TOS > 0); | |
3812 | ||
feff2f05 | 3813 | -- If the saved checks stack overflowed, then we killed all checks, so |
3814 | -- setting the number of saved checks back to zero is correct. This | |
3815 | -- should never occur in practice. | |
9dfe12ae | 3816 | |
3817 | if Saved_Checks_TOS > Saved_Checks_Stack'Last then | |
3818 | Num_Saved_Checks := 0; | |
3819 | ||
feff2f05 | 3820 | -- In the normal case, restore the number of saved checks from the top |
3821 | -- stack entry. | |
9dfe12ae | 3822 | |
3823 | else | |
3824 | Num_Saved_Checks := Saved_Checks_Stack (Saved_Checks_TOS); | |
3825 | if Debug_Flag_CC then | |
3826 | w ("Conditional_Statements_End: Num_Saved_Checks = ", | |
3827 | Num_Saved_Checks); | |
3828 | end if; | |
3829 | end if; | |
3830 | ||
3831 | Saved_Checks_TOS := Saved_Checks_TOS - 1; | |
3832 | end Conditional_Statements_End; | |
3833 | ||
3cce7f32 | 3834 | ------------------------- |
3835 | -- Convert_From_Bignum -- | |
3836 | ------------------------- | |
3837 | ||
3838 | function Convert_From_Bignum (N : Node_Id) return Node_Id is | |
3839 | Loc : constant Source_Ptr := Sloc (N); | |
3840 | ||
3841 | begin | |
3842 | pragma Assert (Is_RTE (Etype (N), RE_Bignum)); | |
3843 | ||
3844 | -- Construct call From Bignum | |
3845 | ||
3846 | return | |
3847 | Make_Function_Call (Loc, | |
3848 | Name => | |
3849 | New_Occurrence_Of (RTE (RE_From_Bignum), Loc), | |
3850 | Parameter_Associations => New_List (Relocate_Node (N))); | |
3851 | end Convert_From_Bignum; | |
3852 | ||
3853 | ----------------------- | |
3854 | -- Convert_To_Bignum -- | |
3855 | ----------------------- | |
3856 | ||
3857 | function Convert_To_Bignum (N : Node_Id) return Node_Id is | |
3858 | Loc : constant Source_Ptr := Sloc (N); | |
3859 | ||
3860 | begin | |
0326b4d4 | 3861 | -- Nothing to do if Bignum already except call Relocate_Node |
3cce7f32 | 3862 | |
3863 | if Is_RTE (Etype (N), RE_Bignum) then | |
3864 | return Relocate_Node (N); | |
3865 | ||
21a55437 | 3866 | -- Otherwise construct call to To_Bignum, converting the operand to the |
3867 | -- required Long_Long_Integer form. | |
3cce7f32 | 3868 | |
3869 | else | |
3870 | pragma Assert (Is_Signed_Integer_Type (Etype (N))); | |
3871 | return | |
3872 | Make_Function_Call (Loc, | |
3873 | Name => | |
3874 | New_Occurrence_Of (RTE (RE_To_Bignum), Loc), | |
3875 | Parameter_Associations => New_List ( | |
3876 | Convert_To (Standard_Long_Long_Integer, Relocate_Node (N)))); | |
3877 | end if; | |
3878 | end Convert_To_Bignum; | |
3879 | ||
ee6ba406 | 3880 | --------------------- |
3881 | -- Determine_Range -- | |
3882 | --------------------- | |
3883 | ||
6af1bdbc | 3884 | Cache_Size : constant := 2 ** 10; |
ee6ba406 | 3885 | type Cache_Index is range 0 .. Cache_Size - 1; |
3886 | -- Determine size of below cache (power of 2 is more efficient!) | |
3887 | ||
3888 | Determine_Range_Cache_N : array (Cache_Index) of Node_Id; | |
9c486805 | 3889 | Determine_Range_Cache_V : array (Cache_Index) of Boolean; |
ee6ba406 | 3890 | Determine_Range_Cache_Lo : array (Cache_Index) of Uint; |
3891 | Determine_Range_Cache_Hi : array (Cache_Index) of Uint; | |
feff2f05 | 3892 | -- The above arrays are used to implement a small direct cache for |
3893 | -- Determine_Range calls. Because of the way Determine_Range recursively | |
3894 | -- traces subexpressions, and because overflow checking calls the routine | |
3895 | -- on the way up the tree, a quadratic behavior can otherwise be | |
3896 | -- encountered in large expressions. The cache entry for node N is stored | |
3897 | -- in the (N mod Cache_Size) entry, and can be validated by checking the | |
9c486805 | 3898 | -- actual node value stored there. The Range_Cache_V array records the |
3899 | -- setting of Assume_Valid for the cache entry. | |
ee6ba406 | 3900 | |
3901 | procedure Determine_Range | |
9c486805 | 3902 | (N : Node_Id; |
3903 | OK : out Boolean; | |
3904 | Lo : out Uint; | |
3905 | Hi : out Uint; | |
3906 | Assume_Valid : Boolean := False) | |
ee6ba406 | 3907 | is |
e254d721 | 3908 | Typ : Entity_Id := Etype (N); |
3909 | -- Type to use, may get reset to base type for possibly invalid entity | |
8880be85 | 3910 | |
3911 | Lo_Left : Uint; | |
3912 | Hi_Left : Uint; | |
3913 | -- Lo and Hi bounds of left operand | |
ee6ba406 | 3914 | |
ee6ba406 | 3915 | Lo_Right : Uint; |
ee6ba406 | 3916 | Hi_Right : Uint; |
8880be85 | 3917 | -- Lo and Hi bounds of right (or only) operand |
3918 | ||
3919 | Bound : Node_Id; | |
3920 | -- Temp variable used to hold a bound node | |
3921 | ||
3922 | Hbound : Uint; | |
3923 | -- High bound of base type of expression | |
3924 | ||
3925 | Lor : Uint; | |
3926 | Hir : Uint; | |
3927 | -- Refined values for low and high bounds, after tightening | |
3928 | ||
3929 | OK1 : Boolean; | |
3930 | -- Used in lower level calls to indicate if call succeeded | |
3931 | ||
3932 | Cindex : Cache_Index; | |
3933 | -- Used to search cache | |
ee6ba406 | 3934 | |
094ed68e | 3935 | Btyp : Entity_Id; |
3936 | -- Base type | |
3937 | ||
ee6ba406 | 3938 | function OK_Operands return Boolean; |
3939 | -- Used for binary operators. Determines the ranges of the left and | |
3940 | -- right operands, and if they are both OK, returns True, and puts | |
341bd953 | 3941 | -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left. |
ee6ba406 | 3942 | |
3943 | ----------------- | |
3944 | -- OK_Operands -- | |
3945 | ----------------- | |
3946 | ||
3947 | function OK_Operands return Boolean is | |
3948 | begin | |
9c486805 | 3949 | Determine_Range |
3950 | (Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid); | |
ee6ba406 | 3951 | |
3952 | if not OK1 then | |
3953 | return False; | |
3954 | end if; | |
3955 | ||
9c486805 | 3956 | Determine_Range |
3957 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
ee6ba406 | 3958 | return OK1; |
3959 | end OK_Operands; | |
3960 | ||
3961 | -- Start of processing for Determine_Range | |
3962 | ||
3963 | begin | |
87bdc21d | 3964 | -- For temporary constants internally generated to remove side effects |
3965 | -- we must use the corresponding expression to determine the range of | |
3966 | -- the expression. | |
3967 | ||
3968 | if Is_Entity_Name (N) | |
3969 | and then Nkind (Parent (Entity (N))) = N_Object_Declaration | |
3970 | and then Ekind (Entity (N)) = E_Constant | |
3971 | and then Is_Internal_Name (Chars (Entity (N))) | |
3972 | then | |
3973 | Determine_Range | |
3974 | (Expression (Parent (Entity (N))), OK, Lo, Hi, Assume_Valid); | |
3975 | return; | |
3976 | end if; | |
3977 | ||
ee6ba406 | 3978 | -- Prevent junk warnings by initializing range variables |
3979 | ||
3980 | Lo := No_Uint; | |
3981 | Hi := No_Uint; | |
3982 | Lor := No_Uint; | |
3983 | Hir := No_Uint; | |
3984 | ||
a781c0fc | 3985 | -- If type is not defined, we can't determine its range |
ee6ba406 | 3986 | |
a781c0fc | 3987 | if No (Typ) |
3988 | ||
3989 | -- We don't deal with anything except discrete types | |
3990 | ||
3991 | or else not Is_Discrete_Type (Typ) | |
3992 | ||
3993 | -- Ignore type for which an error has been posted, since range in | |
3994 | -- this case may well be a bogosity deriving from the error. Also | |
3995 | -- ignore if error posted on the reference node. | |
3996 | ||
3997 | or else Error_Posted (N) or else Error_Posted (Typ) | |
ee6ba406 | 3998 | then |
3999 | OK := False; | |
4000 | return; | |
4001 | end if; | |
4002 | ||
4003 | -- For all other cases, we can determine the range | |
4004 | ||
4005 | OK := True; | |
4006 | ||
feff2f05 | 4007 | -- If value is compile time known, then the possible range is the one |
4008 | -- value that we know this expression definitely has! | |
ee6ba406 | 4009 | |
4010 | if Compile_Time_Known_Value (N) then | |
4011 | Lo := Expr_Value (N); | |
4012 | Hi := Lo; | |
4013 | return; | |
4014 | end if; | |
4015 | ||
4016 | -- Return if already in the cache | |
4017 | ||
4018 | Cindex := Cache_Index (N mod Cache_Size); | |
4019 | ||
9c486805 | 4020 | if Determine_Range_Cache_N (Cindex) = N |
4021 | and then | |
4022 | Determine_Range_Cache_V (Cindex) = Assume_Valid | |
4023 | then | |
ee6ba406 | 4024 | Lo := Determine_Range_Cache_Lo (Cindex); |
4025 | Hi := Determine_Range_Cache_Hi (Cindex); | |
4026 | return; | |
4027 | end if; | |
4028 | ||
feff2f05 | 4029 | -- Otherwise, start by finding the bounds of the type of the expression, |
4030 | -- the value cannot be outside this range (if it is, then we have an | |
4031 | -- overflow situation, which is a separate check, we are talking here | |
4032 | -- only about the expression value). | |
ee6ba406 | 4033 | |
341bd953 | 4034 | -- First a check, never try to find the bounds of a generic type, since |
4035 | -- these bounds are always junk values, and it is only valid to look at | |
4036 | -- the bounds in an instance. | |
4037 | ||
4038 | if Is_Generic_Type (Typ) then | |
4039 | OK := False; | |
4040 | return; | |
4041 | end if; | |
4042 | ||
9c486805 | 4043 | -- First step, change to use base type unless we know the value is valid |
e254d721 | 4044 | |
9c486805 | 4045 | if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N))) |
4046 | or else Assume_No_Invalid_Values | |
4047 | or else Assume_Valid | |
e254d721 | 4048 | then |
9c486805 | 4049 | null; |
4050 | else | |
4051 | Typ := Underlying_Type (Base_Type (Typ)); | |
e254d721 | 4052 | end if; |
4053 | ||
094ed68e | 4054 | -- Retrieve the base type. Handle the case where the base type is a |
4055 | -- private enumeration type. | |
4056 | ||
4057 | Btyp := Base_Type (Typ); | |
4058 | ||
4059 | if Is_Private_Type (Btyp) and then Present (Full_View (Btyp)) then | |
4060 | Btyp := Full_View (Btyp); | |
4061 | end if; | |
4062 | ||
feff2f05 | 4063 | -- We use the actual bound unless it is dynamic, in which case use the |
4064 | -- corresponding base type bound if possible. If we can't get a bound | |
4065 | -- then we figure we can't determine the range (a peculiar case, that | |
4066 | -- perhaps cannot happen, but there is no point in bombing in this | |
4067 | -- optimization circuit. | |
8880be85 | 4068 | |
4069 | -- First the low bound | |
ee6ba406 | 4070 | |
4071 | Bound := Type_Low_Bound (Typ); | |
4072 | ||
4073 | if Compile_Time_Known_Value (Bound) then | |
4074 | Lo := Expr_Value (Bound); | |
4075 | ||
094ed68e | 4076 | elsif Compile_Time_Known_Value (Type_Low_Bound (Btyp)) then |
4077 | Lo := Expr_Value (Type_Low_Bound (Btyp)); | |
ee6ba406 | 4078 | |
4079 | else | |
4080 | OK := False; | |
4081 | return; | |
4082 | end if; | |
4083 | ||
8880be85 | 4084 | -- Now the high bound |
4085 | ||
ee6ba406 | 4086 | Bound := Type_High_Bound (Typ); |
4087 | ||
8880be85 | 4088 | -- We need the high bound of the base type later on, and this should |
4089 | -- always be compile time known. Again, it is not clear that this | |
4090 | -- can ever be false, but no point in bombing. | |
ee6ba406 | 4091 | |
094ed68e | 4092 | if Compile_Time_Known_Value (Type_High_Bound (Btyp)) then |
4093 | Hbound := Expr_Value (Type_High_Bound (Btyp)); | |
ee6ba406 | 4094 | Hi := Hbound; |
4095 | ||
4096 | else | |
4097 | OK := False; | |
4098 | return; | |
4099 | end if; | |
4100 | ||
feff2f05 | 4101 | -- If we have a static subtype, then that may have a tighter bound so |
4102 | -- use the upper bound of the subtype instead in this case. | |
8880be85 | 4103 | |
4104 | if Compile_Time_Known_Value (Bound) then | |
4105 | Hi := Expr_Value (Bound); | |
4106 | end if; | |
4107 | ||
feff2f05 | 4108 | -- We may be able to refine this value in certain situations. If any |
4109 | -- refinement is possible, then Lor and Hir are set to possibly tighter | |
4110 | -- bounds, and OK1 is set to True. | |
ee6ba406 | 4111 | |
4112 | case Nkind (N) is | |
4113 | ||
4114 | -- For unary plus, result is limited by range of operand | |
4115 | ||
4116 | when N_Op_Plus => | |
9c486805 | 4117 | Determine_Range |
4118 | (Right_Opnd (N), OK1, Lor, Hir, Assume_Valid); | |
ee6ba406 | 4119 | |
4120 | -- For unary minus, determine range of operand, and negate it | |
4121 | ||
4122 | when N_Op_Minus => | |
9c486805 | 4123 | Determine_Range |
4124 | (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid); | |
ee6ba406 | 4125 | |
4126 | if OK1 then | |
4127 | Lor := -Hi_Right; | |
4128 | Hir := -Lo_Right; | |
4129 | end if; | |
4130 | ||
4131 | -- For binary addition, get range of each operand and do the | |
4132 | -- addition to get the result range. | |
4133 | ||
4134 | when N_Op_Add => | |
4135 | if OK_Operands then | |
4136 | Lor := Lo_Left + Lo_Right; | |
4137 | Hir := Hi_Left + Hi_Right; | |
4138 | end if; | |
4139 | ||
feff2f05 | 4140 | -- Division is tricky. The only case we consider is where the right |
4141 | -- operand is a positive constant, and in this case we simply divide | |
4142 | -- the bounds of the left operand | |
ee6ba406 | 4143 | |
4144 | when N_Op_Divide => | |
4145 | if OK_Operands then | |
4146 | if Lo_Right = Hi_Right | |
4147 | and then Lo_Right > 0 | |
4148 | then | |
4149 | Lor := Lo_Left / Lo_Right; | |
4150 | Hir := Hi_Left / Lo_Right; | |
4151 | ||
4152 | else | |
4153 | OK1 := False; | |
4154 | end if; | |
4155 | end if; | |
4156 | ||
feff2f05 | 4157 | -- For binary subtraction, get range of each operand and do the worst |
4158 | -- case subtraction to get the result range. | |
ee6ba406 | 4159 | |
4160 | when N_Op_Subtract => | |
4161 | if OK_Operands then | |
4162 | Lor := Lo_Left - Hi_Right; | |
4163 | Hir := Hi_Left - Lo_Right; | |
4164 | end if; | |
4165 | ||
feff2f05 | 4166 | -- For MOD, if right operand is a positive constant, then result must |
4167 | -- be in the allowable range of mod results. | |
ee6ba406 | 4168 | |
4169 | when N_Op_Mod => | |
4170 | if OK_Operands then | |
9dfe12ae | 4171 | if Lo_Right = Hi_Right |
4172 | and then Lo_Right /= 0 | |
4173 | then | |
ee6ba406 | 4174 | if Lo_Right > 0 then |
4175 | Lor := Uint_0; | |
4176 | Hir := Lo_Right - 1; | |
4177 | ||
9dfe12ae | 4178 | else -- Lo_Right < 0 |
ee6ba406 | 4179 | Lor := Lo_Right + 1; |
4180 | Hir := Uint_0; | |
4181 | end if; | |
4182 | ||
4183 | else | |
4184 | OK1 := False; | |
4185 | end if; | |
4186 | end if; | |
4187 | ||
feff2f05 | 4188 | -- For REM, if right operand is a positive constant, then result must |
4189 | -- be in the allowable range of mod results. | |
ee6ba406 | 4190 | |
4191 | when N_Op_Rem => | |
4192 | if OK_Operands then | |
9dfe12ae | 4193 | if Lo_Right = Hi_Right |
4194 | and then Lo_Right /= 0 | |
4195 | then | |
ee6ba406 | 4196 | declare |
4197 | Dval : constant Uint := (abs Lo_Right) - 1; | |
4198 | ||
4199 | begin | |
4200 | -- The sign of the result depends on the sign of the | |
4201 | -- dividend (but not on the sign of the divisor, hence | |
4202 | -- the abs operation above). | |
4203 | ||
4204 | if Lo_Left < 0 then | |
4205 | Lor := -Dval; | |
4206 | else | |
4207 | Lor := Uint_0; | |
4208 | end if; | |
4209 | ||
4210 | if Hi_Left < 0 then | |
4211 | Hir := Uint_0; | |
4212 | else | |
4213 | Hir := Dval; | |
4214 | end if; | |
4215 | end; | |
4216 | ||
4217 | else | |
4218 | OK1 := False; | |
4219 | end if; | |
4220 | end if; | |
4221 | ||
4222 | -- Attribute reference cases | |
4223 | ||
4224 | when N_Attribute_Reference => | |
4225 | case Attribute_Name (N) is | |
4226 | ||
4227 | -- For Pos/Val attributes, we can refine the range using the | |
ddbf7f2e | 4228 | -- possible range of values of the attribute expression. |
ee6ba406 | 4229 | |
4230 | when Name_Pos | Name_Val => | |
9c486805 | 4231 | Determine_Range |
4232 | (First (Expressions (N)), OK1, Lor, Hir, Assume_Valid); | |
ee6ba406 | 4233 | |
4234 | -- For Length attribute, use the bounds of the corresponding | |
4235 | -- index type to refine the range. | |
4236 | ||
4237 | when Name_Length => | |
4238 | declare | |
4239 | Atyp : Entity_Id := Etype (Prefix (N)); | |
4240 | Inum : Nat; | |
4241 | Indx : Node_Id; | |
4242 | ||
4243 | LL, LU : Uint; | |
4244 | UL, UU : Uint; | |
4245 | ||
4246 | begin | |
4247 | if Is_Access_Type (Atyp) then | |
4248 | Atyp := Designated_Type (Atyp); | |
4249 | end if; | |
4250 | ||
4251 | -- For string literal, we know exact value | |
4252 | ||
4253 | if Ekind (Atyp) = E_String_Literal_Subtype then | |
4254 | OK := True; | |
4255 | Lo := String_Literal_Length (Atyp); | |
4256 | Hi := String_Literal_Length (Atyp); | |
4257 | return; | |
4258 | end if; | |
4259 | ||
4260 | -- Otherwise check for expression given | |
4261 | ||
4262 | if No (Expressions (N)) then | |
4263 | Inum := 1; | |
4264 | else | |
4265 | Inum := | |
4266 | UI_To_Int (Expr_Value (First (Expressions (N)))); | |
4267 | end if; | |
4268 | ||
4269 | Indx := First_Index (Atyp); | |
4270 | for J in 2 .. Inum loop | |
4271 | Indx := Next_Index (Indx); | |
4272 | end loop; | |
4273 | ||
9116df93 | 4274 | -- If the index type is a formal type or derived from |
c8da6114 | 4275 | -- one, the bounds are not static. |
4276 | ||
4277 | if Is_Generic_Type (Root_Type (Etype (Indx))) then | |
4278 | OK := False; | |
4279 | return; | |
4280 | end if; | |
4281 | ||
ee6ba406 | 4282 | Determine_Range |
9c486805 | 4283 | (Type_Low_Bound (Etype (Indx)), OK1, LL, LU, |
4284 | Assume_Valid); | |
ee6ba406 | 4285 | |
4286 | if OK1 then | |
4287 | Determine_Range | |
9c486805 | 4288 | (Type_High_Bound (Etype (Indx)), OK1, UL, UU, |
4289 | Assume_Valid); | |
ee6ba406 | 4290 | |
4291 | if OK1 then | |
4292 | ||
4293 | -- The maximum value for Length is the biggest | |
4294 | -- possible gap between the values of the bounds. | |
4295 | -- But of course, this value cannot be negative. | |
4296 | ||
9c486805 | 4297 | Hir := UI_Max (Uint_0, UU - LL + 1); |
ee6ba406 | 4298 | |
4299 | -- For constrained arrays, the minimum value for | |
4300 | -- Length is taken from the actual value of the | |
9116df93 | 4301 | -- bounds, since the index will be exactly of this |
4302 | -- subtype. | |
ee6ba406 | 4303 | |
4304 | if Is_Constrained (Atyp) then | |
9c486805 | 4305 | Lor := UI_Max (Uint_0, UL - LU + 1); |
ee6ba406 | 4306 | |
4307 | -- For an unconstrained array, the minimum value | |
4308 | -- for length is always zero. | |
4309 | ||
4310 | else | |
4311 | Lor := Uint_0; | |
4312 | end if; | |
4313 | end if; | |
4314 | end if; | |
4315 | end; | |
4316 | ||
4317 | -- No special handling for other attributes | |
9116df93 | 4318 | -- Probably more opportunities exist here??? |
ee6ba406 | 4319 | |
4320 | when others => | |
4321 | OK1 := False; | |
4322 | ||
4323 | end case; | |
4324 | ||
feff2f05 | 4325 | -- For type conversion from one discrete type to another, we can |
4326 | -- refine the range using the converted value. | |
ee6ba406 | 4327 | |
4328 | when N_Type_Conversion => | |
9c486805 | 4329 | Determine_Range (Expression (N), OK1, Lor, Hir, Assume_Valid); |
ee6ba406 | 4330 | |
4331 | -- Nothing special to do for all other expression kinds | |
4332 | ||
4333 | when others => | |
4334 | OK1 := False; | |
4335 | Lor := No_Uint; | |
4336 | Hir := No_Uint; | |
4337 | end case; | |
4338 | ||
9116df93 | 4339 | -- At this stage, if OK1 is true, then we know that the actual result of |
4340 | -- the computed expression is in the range Lor .. Hir. We can use this | |
4341 | -- to restrict the possible range of results. | |
ee6ba406 | 4342 | |
4343 | if OK1 then | |
4344 | ||
9116df93 | 4345 | -- If the refined value of the low bound is greater than the type |
4346 | -- high bound, then reset it to the more restrictive value. However, | |
4347 | -- we do NOT do this for the case of a modular type where the | |
4348 | -- possible upper bound on the value is above the base type high | |
4349 | -- bound, because that means the result could wrap. | |
ee6ba406 | 4350 | |
4351 | if Lor > Lo | |
9116df93 | 4352 | and then not (Is_Modular_Integer_Type (Typ) and then Hir > Hbound) |
ee6ba406 | 4353 | then |
4354 | Lo := Lor; | |
4355 | end if; | |
4356 | ||
9116df93 | 4357 | -- Similarly, if the refined value of the high bound is less than the |
4358 | -- value so far, then reset it to the more restrictive value. Again, | |
4359 | -- we do not do this if the refined low bound is negative for a | |
4360 | -- modular type, since this would wrap. | |
ee6ba406 | 4361 | |
4362 | if Hir < Hi | |
9116df93 | 4363 | and then not (Is_Modular_Integer_Type (Typ) and then Lor < Uint_0) |
ee6ba406 | 4364 | then |
4365 | Hi := Hir; | |
4366 | end if; | |
4367 | end if; | |
4368 | ||
4369 | -- Set cache entry for future call and we are all done | |
4370 | ||
4371 | Determine_Range_Cache_N (Cindex) := N; | |
9c486805 | 4372 | Determine_Range_Cache_V (Cindex) := Assume_Valid; |
ee6ba406 | 4373 | Determine_Range_Cache_Lo (Cindex) := Lo; |
4374 | Determine_Range_Cache_Hi (Cindex) := Hi; | |
4375 | return; | |
4376 | ||
9116df93 | 4377 | -- If any exception occurs, it means that we have some bug in the compiler, |
4378 | -- possibly triggered by a previous error, or by some unforeseen peculiar | |
ee6ba406 | 4379 | -- occurrence. However, this is only an optimization attempt, so there is |
4380 | -- really no point in crashing the compiler. Instead we just decide, too | |
4381 | -- bad, we can't figure out a range in this case after all. | |
4382 | ||
4383 | exception | |
4384 | when others => | |
4385 | ||
4386 | -- Debug flag K disables this behavior (useful for debugging) | |
4387 | ||
4388 | if Debug_Flag_K then | |
4389 | raise; | |
4390 | else | |
4391 | OK := False; | |
4392 | Lo := No_Uint; | |
4393 | Hi := No_Uint; | |
4394 | return; | |
4395 | end if; | |
ee6ba406 | 4396 | end Determine_Range; |
4397 | ||
4398 | ------------------------------------ | |
4399 | -- Discriminant_Checks_Suppressed -- | |
4400 | ------------------------------------ | |
4401 | ||
4402 | function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is | |
4403 | begin | |
9dfe12ae | 4404 | if Present (E) then |
4405 | if Is_Unchecked_Union (E) then | |
4406 | return True; | |
4407 | elsif Checks_May_Be_Suppressed (E) then | |
4408 | return Is_Check_Suppressed (E, Discriminant_Check); | |
4409 | end if; | |
4410 | end if; | |
4411 | ||
fafc6b97 | 4412 | return Scope_Suppress.Suppress (Discriminant_Check); |
ee6ba406 | 4413 | end Discriminant_Checks_Suppressed; |
4414 | ||
4415 | -------------------------------- | |
4416 | -- Division_Checks_Suppressed -- | |
4417 | -------------------------------- | |
4418 | ||
4419 | function Division_Checks_Suppressed (E : Entity_Id) return Boolean is | |
4420 | begin | |
9dfe12ae | 4421 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
4422 | return Is_Check_Suppressed (E, Division_Check); | |
4423 | else | |
fafc6b97 | 4424 | return Scope_Suppress.Suppress (Division_Check); |
9dfe12ae | 4425 | end if; |
ee6ba406 | 4426 | end Division_Checks_Suppressed; |
4427 | ||
4428 | ----------------------------------- | |
4429 | -- Elaboration_Checks_Suppressed -- | |
4430 | ----------------------------------- | |
4431 | ||
4432 | function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is | |
4433 | begin | |
38f5559f | 4434 | -- The complication in this routine is that if we are in the dynamic |
4435 | -- model of elaboration, we also check All_Checks, since All_Checks | |
4436 | -- does not set Elaboration_Check explicitly. | |
4437 | ||
9dfe12ae | 4438 | if Present (E) then |
4439 | if Kill_Elaboration_Checks (E) then | |
4440 | return True; | |
38f5559f | 4441 | |
9dfe12ae | 4442 | elsif Checks_May_Be_Suppressed (E) then |
38f5559f | 4443 | if Is_Check_Suppressed (E, Elaboration_Check) then |
4444 | return True; | |
4445 | elsif Dynamic_Elaboration_Checks then | |
4446 | return Is_Check_Suppressed (E, All_Checks); | |
4447 | else | |
4448 | return False; | |
4449 | end if; | |
9dfe12ae | 4450 | end if; |
4451 | end if; | |
4452 | ||
fafc6b97 | 4453 | if Scope_Suppress.Suppress (Elaboration_Check) then |
38f5559f | 4454 | return True; |
4455 | elsif Dynamic_Elaboration_Checks then | |
fafc6b97 | 4456 | return Scope_Suppress.Suppress (All_Checks); |
38f5559f | 4457 | else |
4458 | return False; | |
4459 | end if; | |
ee6ba406 | 4460 | end Elaboration_Checks_Suppressed; |
4461 | ||
9dfe12ae | 4462 | --------------------------- |
4463 | -- Enable_Overflow_Check -- | |
4464 | --------------------------- | |
4465 | ||
4466 | procedure Enable_Overflow_Check (N : Node_Id) is | |
3cce7f32 | 4467 | Typ : constant Entity_Id := Base_Type (Etype (N)); |
db415383 | 4468 | Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
3cce7f32 | 4469 | Chk : Nat; |
4470 | OK : Boolean; | |
4471 | Ent : Entity_Id; | |
4472 | Ofs : Uint; | |
4473 | Lo : Uint; | |
4474 | Hi : Uint; | |
ee6ba406 | 4475 | |
ee6ba406 | 4476 | begin |
9dfe12ae | 4477 | if Debug_Flag_CC then |
4478 | w ("Enable_Overflow_Check for node ", Int (N)); | |
4479 | Write_Str (" Source location = "); | |
4480 | wl (Sloc (N)); | |
00c403ee | 4481 | pg (Union_Id (N)); |
ee6ba406 | 4482 | end if; |
ee6ba406 | 4483 | |
75209ec5 | 4484 | -- No check if overflow checks suppressed for type of node |
4485 | ||
0df9d43f | 4486 | if Overflow_Checks_Suppressed (Etype (N)) then |
75209ec5 | 4487 | return; |
4488 | ||
49260fa5 | 4489 | -- Nothing to do for unsigned integer types, which do not overflow |
4490 | ||
4491 | elsif Is_Modular_Integer_Type (Typ) then | |
4492 | return; | |
3cce7f32 | 4493 | end if; |
4494 | ||
0df9d43f | 4495 | -- This is the point at which processing for STRICT mode diverges |
21a55437 | 4496 | -- from processing for MINIMIZED/ELIMINATED modes. This divergence is |
4497 | -- probably more extreme that it needs to be, but what is going on here | |
4498 | -- is that when we introduced MINIMIZED/ELIMINATED modes, we wanted | |
0df9d43f | 4499 | -- to leave the processing for STRICT mode untouched. There were |
21a55437 | 4500 | -- two reasons for this. First it avoided any incompatible change of |
0df9d43f | 4501 | -- behavior. Second, it guaranteed that STRICT mode continued to be |
21a55437 | 4502 | -- legacy reliable. |
3cce7f32 | 4503 | |
0df9d43f | 4504 | -- The big difference is that in STRICT mode there is a fair amount of |
3cce7f32 | 4505 | -- circuitry to try to avoid setting the Do_Overflow_Check flag if we |
4506 | -- know that no check is needed. We skip all that in the two new modes, | |
4507 | -- since really overflow checking happens over a whole subtree, and we | |
4508 | -- do the corresponding optimizations later on when applying the checks. | |
4509 | ||
4510 | if Mode in Minimized_Or_Eliminated then | |
0df9d43f | 4511 | if not (Overflow_Checks_Suppressed (Etype (N))) |
4512 | and then not (Is_Entity_Name (N) | |
4513 | and then Overflow_Checks_Suppressed (Entity (N))) | |
4514 | then | |
4515 | Activate_Overflow_Check (N); | |
4516 | end if; | |
3cce7f32 | 4517 | |
4518 | if Debug_Flag_CC then | |
4519 | w ("Minimized/Eliminated mode"); | |
4520 | end if; | |
4521 | ||
4522 | return; | |
4523 | end if; | |
4524 | ||
0df9d43f | 4525 | -- Remainder of processing is for STRICT case, and is unchanged from |
691fe9e0 | 4526 | -- earlier versions preceding the addition of MINIMIZED/ELIMINATED. |
49260fa5 | 4527 | |
feff2f05 | 4528 | -- Nothing to do if the range of the result is known OK. We skip this |
4529 | -- for conversions, since the caller already did the check, and in any | |
4530 | -- case the condition for deleting the check for a type conversion is | |
cc60bd16 | 4531 | -- different. |
ee6ba406 | 4532 | |
3cce7f32 | 4533 | if Nkind (N) /= N_Type_Conversion then |
9c486805 | 4534 | Determine_Range (N, OK, Lo, Hi, Assume_Valid => True); |
ee6ba406 | 4535 | |
cc60bd16 | 4536 | -- Note in the test below that we assume that the range is not OK |
4537 | -- if a bound of the range is equal to that of the type. That's not | |
4538 | -- quite accurate but we do this for the following reasons: | |
ee6ba406 | 4539 | |
9dfe12ae | 4540 | -- a) The way that Determine_Range works, it will typically report |
4541 | -- the bounds of the value as being equal to the bounds of the | |
4542 | -- type, because it either can't tell anything more precise, or | |
4543 | -- does not think it is worth the effort to be more precise. | |
ee6ba406 | 4544 | |
9dfe12ae | 4545 | -- b) It is very unusual to have a situation in which this would |
4546 | -- generate an unnecessary overflow check (an example would be | |
4547 | -- a subtype with a range 0 .. Integer'Last - 1 to which the | |
cc60bd16 | 4548 | -- literal value one is added). |
ee6ba406 | 4549 | |
9dfe12ae | 4550 | -- c) The alternative is a lot of special casing in this routine |
4551 | -- which would partially duplicate Determine_Range processing. | |
ee6ba406 | 4552 | |
9dfe12ae | 4553 | if OK |
4554 | and then Lo > Expr_Value (Type_Low_Bound (Typ)) | |
4555 | and then Hi < Expr_Value (Type_High_Bound (Typ)) | |
4556 | then | |
4557 | if Debug_Flag_CC then | |
4558 | w ("No overflow check required"); | |
4559 | end if; | |
4560 | ||
4561 | return; | |
4562 | end if; | |
4563 | end if; | |
4564 | ||
feff2f05 | 4565 | -- If not in optimizing mode, set flag and we are done. We are also done |
4566 | -- (and just set the flag) if the type is not a discrete type, since it | |
4567 | -- is not worth the effort to eliminate checks for other than discrete | |
4568 | -- types. In addition, we take this same path if we have stored the | |
4569 | -- maximum number of checks possible already (a very unlikely situation, | |
4570 | -- but we do not want to blow up!) | |
9dfe12ae | 4571 | |
4572 | if Optimization_Level = 0 | |
4573 | or else not Is_Discrete_Type (Etype (N)) | |
4574 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 4575 | then |
00c403ee | 4576 | Activate_Overflow_Check (N); |
9dfe12ae | 4577 | |
4578 | if Debug_Flag_CC then | |
4579 | w ("Optimization off"); | |
4580 | end if; | |
4581 | ||
ee6ba406 | 4582 | return; |
9dfe12ae | 4583 | end if; |
ee6ba406 | 4584 | |
9dfe12ae | 4585 | -- Otherwise evaluate and check the expression |
4586 | ||
4587 | Find_Check | |
4588 | (Expr => N, | |
4589 | Check_Type => 'O', | |
4590 | Target_Type => Empty, | |
4591 | Entry_OK => OK, | |
4592 | Check_Num => Chk, | |
4593 | Ent => Ent, | |
4594 | Ofs => Ofs); | |
4595 | ||
4596 | if Debug_Flag_CC then | |
4597 | w ("Called Find_Check"); | |
4598 | w (" OK = ", OK); | |
4599 | ||
4600 | if OK then | |
4601 | w (" Check_Num = ", Chk); | |
4602 | w (" Ent = ", Int (Ent)); | |
4603 | Write_Str (" Ofs = "); | |
4604 | pid (Ofs); | |
4605 | end if; | |
4606 | end if; | |
ee6ba406 | 4607 | |
9dfe12ae | 4608 | -- If check is not of form to optimize, then set flag and we are done |
4609 | ||
4610 | if not OK then | |
00c403ee | 4611 | Activate_Overflow_Check (N); |
ee6ba406 | 4612 | return; |
9dfe12ae | 4613 | end if; |
ee6ba406 | 4614 | |
9dfe12ae | 4615 | -- If check is already performed, then return without setting flag |
4616 | ||
4617 | if Chk /= 0 then | |
4618 | if Debug_Flag_CC then | |
4619 | w ("Check suppressed!"); | |
4620 | end if; | |
ee6ba406 | 4621 | |
ee6ba406 | 4622 | return; |
9dfe12ae | 4623 | end if; |
ee6ba406 | 4624 | |
9dfe12ae | 4625 | -- Here we will make a new entry for the new check |
4626 | ||
00c403ee | 4627 | Activate_Overflow_Check (N); |
9dfe12ae | 4628 | Num_Saved_Checks := Num_Saved_Checks + 1; |
4629 | Saved_Checks (Num_Saved_Checks) := | |
4630 | (Killed => False, | |
4631 | Entity => Ent, | |
4632 | Offset => Ofs, | |
4633 | Check_Type => 'O', | |
4634 | Target_Type => Empty); | |
4635 | ||
4636 | if Debug_Flag_CC then | |
4637 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
4638 | w (" Entity = ", Int (Ent)); | |
4639 | Write_Str (" Offset = "); | |
4640 | pid (Ofs); | |
4641 | w (" Check_Type = O"); | |
4642 | w (" Target_Type = Empty"); | |
4643 | end if; | |
ee6ba406 | 4644 | |
feff2f05 | 4645 | -- If we get an exception, then something went wrong, probably because of |
4646 | -- an error in the structure of the tree due to an incorrect program. Or it | |
4647 | -- may be a bug in the optimization circuit. In either case the safest | |
4648 | -- thing is simply to set the check flag unconditionally. | |
9dfe12ae | 4649 | |
4650 | exception | |
4651 | when others => | |
00c403ee | 4652 | Activate_Overflow_Check (N); |
9dfe12ae | 4653 | |
4654 | if Debug_Flag_CC then | |
4655 | w (" exception occurred, overflow flag set"); | |
4656 | end if; | |
4657 | ||
4658 | return; | |
4659 | end Enable_Overflow_Check; | |
4660 | ||
4661 | ------------------------ | |
4662 | -- Enable_Range_Check -- | |
4663 | ------------------------ | |
4664 | ||
4665 | procedure Enable_Range_Check (N : Node_Id) is | |
4666 | Chk : Nat; | |
4667 | OK : Boolean; | |
4668 | Ent : Entity_Id; | |
4669 | Ofs : Uint; | |
4670 | Ttyp : Entity_Id; | |
4671 | P : Node_Id; | |
4672 | ||
4673 | begin | |
feff2f05 | 4674 | -- Return if unchecked type conversion with range check killed. In this |
4675 | -- case we never set the flag (that's what Kill_Range_Check is about!) | |
9dfe12ae | 4676 | |
4677 | if Nkind (N) = N_Unchecked_Type_Conversion | |
4678 | and then Kill_Range_Check (N) | |
ee6ba406 | 4679 | then |
4680 | return; | |
9dfe12ae | 4681 | end if; |
ee6ba406 | 4682 | |
55e8372b | 4683 | -- Do not set range check flag if parent is assignment statement or |
4684 | -- object declaration with Suppress_Assignment_Checks flag set | |
4685 | ||
4686 | if Nkind_In (Parent (N), N_Assignment_Statement, N_Object_Declaration) | |
4687 | and then Suppress_Assignment_Checks (Parent (N)) | |
4688 | then | |
4689 | return; | |
4690 | end if; | |
4691 | ||
0577b0b1 | 4692 | -- Check for various cases where we should suppress the range check |
4693 | ||
4694 | -- No check if range checks suppressed for type of node | |
4695 | ||
4696 | if Present (Etype (N)) | |
4697 | and then Range_Checks_Suppressed (Etype (N)) | |
4698 | then | |
4699 | return; | |
4700 | ||
4701 | -- No check if node is an entity name, and range checks are suppressed | |
4702 | -- for this entity, or for the type of this entity. | |
4703 | ||
4704 | elsif Is_Entity_Name (N) | |
4705 | and then (Range_Checks_Suppressed (Entity (N)) | |
4706 | or else Range_Checks_Suppressed (Etype (Entity (N)))) | |
4707 | then | |
4708 | return; | |
4709 | ||
4710 | -- No checks if index of array, and index checks are suppressed for | |
4711 | -- the array object or the type of the array. | |
4712 | ||
4713 | elsif Nkind (Parent (N)) = N_Indexed_Component then | |
4714 | declare | |
4715 | Pref : constant Node_Id := Prefix (Parent (N)); | |
4716 | begin | |
4717 | if Is_Entity_Name (Pref) | |
4718 | and then Index_Checks_Suppressed (Entity (Pref)) | |
4719 | then | |
4720 | return; | |
4721 | elsif Index_Checks_Suppressed (Etype (Pref)) then | |
4722 | return; | |
4723 | end if; | |
4724 | end; | |
4725 | end if; | |
4726 | ||
9dfe12ae | 4727 | -- Debug trace output |
ee6ba406 | 4728 | |
9dfe12ae | 4729 | if Debug_Flag_CC then |
4730 | w ("Enable_Range_Check for node ", Int (N)); | |
4731 | Write_Str (" Source location = "); | |
4732 | wl (Sloc (N)); | |
00c403ee | 4733 | pg (Union_Id (N)); |
9dfe12ae | 4734 | end if; |
4735 | ||
feff2f05 | 4736 | -- If not in optimizing mode, set flag and we are done. We are also done |
4737 | -- (and just set the flag) if the type is not a discrete type, since it | |
4738 | -- is not worth the effort to eliminate checks for other than discrete | |
4739 | -- types. In addition, we take this same path if we have stored the | |
4740 | -- maximum number of checks possible already (a very unlikely situation, | |
4741 | -- but we do not want to blow up!) | |
9dfe12ae | 4742 | |
4743 | if Optimization_Level = 0 | |
4744 | or else No (Etype (N)) | |
4745 | or else not Is_Discrete_Type (Etype (N)) | |
4746 | or else Num_Saved_Checks = Saved_Checks'Last | |
ee6ba406 | 4747 | then |
00c403ee | 4748 | Activate_Range_Check (N); |
9dfe12ae | 4749 | |
4750 | if Debug_Flag_CC then | |
4751 | w ("Optimization off"); | |
4752 | end if; | |
4753 | ||
ee6ba406 | 4754 | return; |
9dfe12ae | 4755 | end if; |
ee6ba406 | 4756 | |
9dfe12ae | 4757 | -- Otherwise find out the target type |
ee6ba406 | 4758 | |
9dfe12ae | 4759 | P := Parent (N); |
ee6ba406 | 4760 | |
9dfe12ae | 4761 | -- For assignment, use left side subtype |
4762 | ||
4763 | if Nkind (P) = N_Assignment_Statement | |
4764 | and then Expression (P) = N | |
4765 | then | |
4766 | Ttyp := Etype (Name (P)); | |
4767 | ||
4768 | -- For indexed component, use subscript subtype | |
4769 | ||
4770 | elsif Nkind (P) = N_Indexed_Component then | |
4771 | declare | |
4772 | Atyp : Entity_Id; | |
4773 | Indx : Node_Id; | |
4774 | Subs : Node_Id; | |
4775 | ||
4776 | begin | |
4777 | Atyp := Etype (Prefix (P)); | |
4778 | ||
4779 | if Is_Access_Type (Atyp) then | |
4780 | Atyp := Designated_Type (Atyp); | |
f07ea091 | 4781 | |
4782 | -- If the prefix is an access to an unconstrained array, | |
feff2f05 | 4783 | -- perform check unconditionally: it depends on the bounds of |
4784 | -- an object and we cannot currently recognize whether the test | |
4785 | -- may be redundant. | |
f07ea091 | 4786 | |
4787 | if not Is_Constrained (Atyp) then | |
00c403ee | 4788 | Activate_Range_Check (N); |
f07ea091 | 4789 | return; |
4790 | end if; | |
7189d17f | 4791 | |
feff2f05 | 4792 | -- Ditto if the prefix is an explicit dereference whose designated |
4793 | -- type is unconstrained. | |
7189d17f | 4794 | |
4795 | elsif Nkind (Prefix (P)) = N_Explicit_Dereference | |
4796 | and then not Is_Constrained (Atyp) | |
4797 | then | |
00c403ee | 4798 | Activate_Range_Check (N); |
7189d17f | 4799 | return; |
9dfe12ae | 4800 | end if; |
4801 | ||
4802 | Indx := First_Index (Atyp); | |
4803 | Subs := First (Expressions (P)); | |
4804 | loop | |
4805 | if Subs = N then | |
4806 | Ttyp := Etype (Indx); | |
4807 | exit; | |
4808 | end if; | |
4809 | ||
4810 | Next_Index (Indx); | |
4811 | Next (Subs); | |
4812 | end loop; | |
4813 | end; | |
4814 | ||
4815 | -- For now, ignore all other cases, they are not so interesting | |
4816 | ||
4817 | else | |
4818 | if Debug_Flag_CC then | |
4819 | w (" target type not found, flag set"); | |
4820 | end if; | |
4821 | ||
00c403ee | 4822 | Activate_Range_Check (N); |
9dfe12ae | 4823 | return; |
4824 | end if; | |
4825 | ||
4826 | -- Evaluate and check the expression | |
4827 | ||
4828 | Find_Check | |
4829 | (Expr => N, | |
4830 | Check_Type => 'R', | |
4831 | Target_Type => Ttyp, | |
4832 | Entry_OK => OK, | |
4833 | Check_Num => Chk, | |
4834 | Ent => Ent, | |
4835 | Ofs => Ofs); | |
4836 | ||
4837 | if Debug_Flag_CC then | |
4838 | w ("Called Find_Check"); | |
4839 | w ("Target_Typ = ", Int (Ttyp)); | |
4840 | w (" OK = ", OK); | |
4841 | ||
4842 | if OK then | |
4843 | w (" Check_Num = ", Chk); | |
4844 | w (" Ent = ", Int (Ent)); | |
4845 | Write_Str (" Ofs = "); | |
4846 | pid (Ofs); | |
4847 | end if; | |
4848 | end if; | |
4849 | ||
4850 | -- If check is not of form to optimize, then set flag and we are done | |
4851 | ||
4852 | if not OK then | |
4853 | if Debug_Flag_CC then | |
4854 | w (" expression not of optimizable type, flag set"); | |
4855 | end if; | |
4856 | ||
00c403ee | 4857 | Activate_Range_Check (N); |
9dfe12ae | 4858 | return; |
4859 | end if; | |
4860 | ||
4861 | -- If check is already performed, then return without setting flag | |
4862 | ||
4863 | if Chk /= 0 then | |
4864 | if Debug_Flag_CC then | |
4865 | w ("Check suppressed!"); | |
4866 | end if; | |
4867 | ||
4868 | return; | |
4869 | end if; | |
4870 | ||
4871 | -- Here we will make a new entry for the new check | |
4872 | ||
00c403ee | 4873 | Activate_Range_Check (N); |
9dfe12ae | 4874 | Num_Saved_Checks := Num_Saved_Checks + 1; |
4875 | Saved_Checks (Num_Saved_Checks) := | |
4876 | (Killed => False, | |
4877 | Entity => Ent, | |
4878 | Offset => Ofs, | |
4879 | Check_Type => 'R', | |
4880 | Target_Type => Ttyp); | |
4881 | ||
4882 | if Debug_Flag_CC then | |
4883 | w ("Make new entry, check number = ", Num_Saved_Checks); | |
4884 | w (" Entity = ", Int (Ent)); | |
4885 | Write_Str (" Offset = "); | |
4886 | pid (Ofs); | |
4887 | w (" Check_Type = R"); | |
4888 | w (" Target_Type = ", Int (Ttyp)); | |
00c403ee | 4889 | pg (Union_Id (Ttyp)); |
9dfe12ae | 4890 | end if; |
4891 | ||
feff2f05 | 4892 | -- If we get an exception, then something went wrong, probably because of |
4893 | -- an error in the structure of the tree due to an incorrect program. Or | |
4894 | -- it may be a bug in the optimization circuit. In either case the safest | |
4895 | -- thing is simply to set the check flag unconditionally. | |
9dfe12ae | 4896 | |
4897 | exception | |
4898 | when others => | |
00c403ee | 4899 | Activate_Range_Check (N); |
9dfe12ae | 4900 | |
4901 | if Debug_Flag_CC then | |
4902 | w (" exception occurred, range flag set"); | |
4903 | end if; | |
4904 | ||
4905 | return; | |
4906 | end Enable_Range_Check; | |
4907 | ||
4908 | ------------------ | |
4909 | -- Ensure_Valid -- | |
4910 | ------------------ | |
4911 | ||
4912 | procedure Ensure_Valid (Expr : Node_Id; Holes_OK : Boolean := False) is | |
4913 | Typ : constant Entity_Id := Etype (Expr); | |
4914 | ||
4915 | begin | |
4916 | -- Ignore call if we are not doing any validity checking | |
4917 | ||
4918 | if not Validity_Checks_On then | |
4919 | return; | |
4920 | ||
0577b0b1 | 4921 | -- Ignore call if range or validity checks suppressed on entity or type |
9dfe12ae | 4922 | |
0577b0b1 | 4923 | elsif Range_Or_Validity_Checks_Suppressed (Expr) then |
9dfe12ae | 4924 | return; |
4925 | ||
feff2f05 | 4926 | -- No check required if expression is from the expander, we assume the |
4927 | -- expander will generate whatever checks are needed. Note that this is | |
4928 | -- not just an optimization, it avoids infinite recursions! | |
9dfe12ae | 4929 | |
4930 | -- Unchecked conversions must be checked, unless they are initialized | |
4931 | -- scalar values, as in a component assignment in an init proc. | |
4932 | ||
4933 | -- In addition, we force a check if Force_Validity_Checks is set | |
4934 | ||
4935 | elsif not Comes_From_Source (Expr) | |
4936 | and then not Force_Validity_Checks | |
4937 | and then (Nkind (Expr) /= N_Unchecked_Type_Conversion | |
4938 | or else Kill_Range_Check (Expr)) | |
4939 | then | |
4940 | return; | |
4941 | ||
4942 | -- No check required if expression is known to have valid value | |
4943 | ||
4944 | elsif Expr_Known_Valid (Expr) then | |
4945 | return; | |
4946 | ||
feff2f05 | 4947 | -- Ignore case of enumeration with holes where the flag is set not to |
4948 | -- worry about holes, since no special validity check is needed | |
9dfe12ae | 4949 | |
4950 | elsif Is_Enumeration_Type (Typ) | |
4951 | and then Has_Non_Standard_Rep (Typ) | |
4952 | and then Holes_OK | |
4953 | then | |
4954 | return; | |
4955 | ||
f2a06be9 | 4956 | -- No check required on the left-hand side of an assignment |
9dfe12ae | 4957 | |
4958 | elsif Nkind (Parent (Expr)) = N_Assignment_Statement | |
4959 | and then Expr = Name (Parent (Expr)) | |
4960 | then | |
4961 | return; | |
4962 | ||
6fb3c314 | 4963 | -- No check on a universal real constant. The context will eventually |
38f5559f | 4964 | -- convert it to a machine number for some target type, or report an |
4965 | -- illegality. | |
4966 | ||
4967 | elsif Nkind (Expr) = N_Real_Literal | |
4968 | and then Etype (Expr) = Universal_Real | |
4969 | then | |
4970 | return; | |
4971 | ||
6fb3c314 | 4972 | -- If the expression denotes a component of a packed boolean array, |
0577b0b1 | 4973 | -- no possible check applies. We ignore the old ACATS chestnuts that |
4974 | -- involve Boolean range True..True. | |
4975 | ||
4976 | -- Note: validity checks are generated for expressions that yield a | |
4977 | -- scalar type, when it is possible to create a value that is outside of | |
4978 | -- the type. If this is a one-bit boolean no such value exists. This is | |
4979 | -- an optimization, and it also prevents compiler blowing up during the | |
4980 | -- elaboration of improperly expanded packed array references. | |
4981 | ||
4982 | elsif Nkind (Expr) = N_Indexed_Component | |
4983 | and then Is_Bit_Packed_Array (Etype (Prefix (Expr))) | |
4984 | and then Root_Type (Etype (Expr)) = Standard_Boolean | |
4985 | then | |
4986 | return; | |
4987 | ||
9dfe12ae | 4988 | -- An annoying special case. If this is an out parameter of a scalar |
4989 | -- type, then the value is not going to be accessed, therefore it is | |
4990 | -- inappropriate to do any validity check at the call site. | |
4991 | ||
4992 | else | |
4993 | -- Only need to worry about scalar types | |
4994 | ||
4995 | if Is_Scalar_Type (Typ) then | |
ee6ba406 | 4996 | declare |
4997 | P : Node_Id; | |
4998 | N : Node_Id; | |
4999 | E : Entity_Id; | |
5000 | F : Entity_Id; | |
5001 | A : Node_Id; | |
5002 | L : List_Id; | |
5003 | ||
5004 | begin | |
5005 | -- Find actual argument (which may be a parameter association) | |
5006 | -- and the parent of the actual argument (the call statement) | |
5007 | ||
5008 | N := Expr; | |
5009 | P := Parent (Expr); | |
5010 | ||
5011 | if Nkind (P) = N_Parameter_Association then | |
5012 | N := P; | |
5013 | P := Parent (N); | |
5014 | end if; | |
5015 | ||
feff2f05 | 5016 | -- Only need to worry if we are argument of a procedure call |
5017 | -- since functions don't have out parameters. If this is an | |
5018 | -- indirect or dispatching call, get signature from the | |
5019 | -- subprogram type. | |
ee6ba406 | 5020 | |
5021 | if Nkind (P) = N_Procedure_Call_Statement then | |
5022 | L := Parameter_Associations (P); | |
9dfe12ae | 5023 | |
5024 | if Is_Entity_Name (Name (P)) then | |
5025 | E := Entity (Name (P)); | |
5026 | else | |
5027 | pragma Assert (Nkind (Name (P)) = N_Explicit_Dereference); | |
5028 | E := Etype (Name (P)); | |
5029 | end if; | |
ee6ba406 | 5030 | |
feff2f05 | 5031 | -- Only need to worry if there are indeed actuals, and if |
5032 | -- this could be a procedure call, otherwise we cannot get a | |
5033 | -- match (either we are not an argument, or the mode of the | |
5034 | -- formal is not OUT). This test also filters out the | |
5035 | -- generic case. | |
ee6ba406 | 5036 | |
5037 | if Is_Non_Empty_List (L) | |
5038 | and then Is_Subprogram (E) | |
5039 | then | |
feff2f05 | 5040 | -- This is the loop through parameters, looking for an |
5041 | -- OUT parameter for which we are the argument. | |
ee6ba406 | 5042 | |
5043 | F := First_Formal (E); | |
5044 | A := First (L); | |
ee6ba406 | 5045 | while Present (F) loop |
5046 | if Ekind (F) = E_Out_Parameter and then A = N then | |
5047 | return; | |
5048 | end if; | |
5049 | ||
5050 | Next_Formal (F); | |
5051 | Next (A); | |
5052 | end loop; | |
5053 | end if; | |
5054 | end if; | |
5055 | end; | |
5056 | end if; | |
5057 | end if; | |
5058 | ||
fa6a6949 | 5059 | -- If this is a boolean expression, only its elementary operands need |
90a07d4c | 5060 | -- checking: if they are valid, a boolean or short-circuit operation |
5061 | -- with them will be valid as well. | |
784d4230 | 5062 | |
5063 | if Base_Type (Typ) = Standard_Boolean | |
7af38999 | 5064 | and then |
fa6a6949 | 5065 | (Nkind (Expr) in N_Op or else Nkind (Expr) in N_Short_Circuit) |
784d4230 | 5066 | then |
5067 | return; | |
5068 | end if; | |
5069 | ||
0577b0b1 | 5070 | -- If we fall through, a validity check is required |
ee6ba406 | 5071 | |
5072 | Insert_Valid_Check (Expr); | |
ce7498d3 | 5073 | |
5074 | if Is_Entity_Name (Expr) | |
5075 | and then Safe_To_Capture_Value (Expr, Entity (Expr)) | |
5076 | then | |
5077 | Set_Is_Known_Valid (Entity (Expr)); | |
5078 | end if; | |
ee6ba406 | 5079 | end Ensure_Valid; |
5080 | ||
5081 | ---------------------- | |
5082 | -- Expr_Known_Valid -- | |
5083 | ---------------------- | |
5084 | ||
5085 | function Expr_Known_Valid (Expr : Node_Id) return Boolean is | |
5086 | Typ : constant Entity_Id := Etype (Expr); | |
5087 | ||
5088 | begin | |
feff2f05 | 5089 | -- Non-scalar types are always considered valid, since they never give |
5090 | -- rise to the issues of erroneous or bounded error behavior that are | |
5091 | -- the concern. In formal reference manual terms the notion of validity | |
5092 | -- only applies to scalar types. Note that even when packed arrays are | |
5093 | -- represented using modular types, they are still arrays semantically, | |
5094 | -- so they are also always valid (in particular, the unused bits can be | |
5095 | -- random rubbish without affecting the validity of the array value). | |
ee6ba406 | 5096 | |
fa814356 | 5097 | if not Is_Scalar_Type (Typ) or else Is_Packed_Array_Type (Typ) then |
ee6ba406 | 5098 | return True; |
5099 | ||
5100 | -- If no validity checking, then everything is considered valid | |
5101 | ||
5102 | elsif not Validity_Checks_On then | |
5103 | return True; | |
5104 | ||
5105 | -- Floating-point types are considered valid unless floating-point | |
5106 | -- validity checks have been specifically turned on. | |
5107 | ||
5108 | elsif Is_Floating_Point_Type (Typ) | |
5109 | and then not Validity_Check_Floating_Point | |
5110 | then | |
5111 | return True; | |
5112 | ||
feff2f05 | 5113 | -- If the expression is the value of an object that is known to be |
5114 | -- valid, then clearly the expression value itself is valid. | |
ee6ba406 | 5115 | |
5116 | elsif Is_Entity_Name (Expr) | |
5117 | and then Is_Known_Valid (Entity (Expr)) | |
5118 | then | |
5119 | return True; | |
5120 | ||
0577b0b1 | 5121 | -- References to discriminants are always considered valid. The value |
5122 | -- of a discriminant gets checked when the object is built. Within the | |
5123 | -- record, we consider it valid, and it is important to do so, since | |
5124 | -- otherwise we can try to generate bogus validity checks which | |
feff2f05 | 5125 | -- reference discriminants out of scope. Discriminants of concurrent |
5126 | -- types are excluded for the same reason. | |
0577b0b1 | 5127 | |
5128 | elsif Is_Entity_Name (Expr) | |
feff2f05 | 5129 | and then Denotes_Discriminant (Expr, Check_Concurrent => True) |
0577b0b1 | 5130 | then |
5131 | return True; | |
5132 | ||
feff2f05 | 5133 | -- If the type is one for which all values are known valid, then we are |
5134 | -- sure that the value is valid except in the slightly odd case where | |
5135 | -- the expression is a reference to a variable whose size has been | |
5136 | -- explicitly set to a value greater than the object size. | |
ee6ba406 | 5137 | |
5138 | elsif Is_Known_Valid (Typ) then | |
5139 | if Is_Entity_Name (Expr) | |
5140 | and then Ekind (Entity (Expr)) = E_Variable | |
5141 | and then Esize (Entity (Expr)) > Esize (Typ) | |
5142 | then | |
5143 | return False; | |
5144 | else | |
5145 | return True; | |
5146 | end if; | |
5147 | ||
5148 | -- Integer and character literals always have valid values, where | |
5149 | -- appropriate these will be range checked in any case. | |
5150 | ||
5151 | elsif Nkind (Expr) = N_Integer_Literal | |
5152 | or else | |
5153 | Nkind (Expr) = N_Character_Literal | |
5154 | then | |
5155 | return True; | |
5156 | ||
91e47010 | 5157 | -- Real literals are assumed to be valid in VM targets |
5158 | ||
5159 | elsif VM_Target /= No_VM | |
5160 | and then Nkind (Expr) = N_Real_Literal | |
5161 | then | |
5162 | return True; | |
5163 | ||
ee6ba406 | 5164 | -- If we have a type conversion or a qualification of a known valid |
5165 | -- value, then the result will always be valid. | |
5166 | ||
5167 | elsif Nkind (Expr) = N_Type_Conversion | |
5168 | or else | |
5169 | Nkind (Expr) = N_Qualified_Expression | |
5170 | then | |
5171 | return Expr_Known_Valid (Expression (Expr)); | |
5172 | ||
38f5559f | 5173 | -- The result of any operator is always considered valid, since we |
5174 | -- assume the necessary checks are done by the operator. For operators | |
5175 | -- on floating-point operations, we must also check when the operation | |
5176 | -- is the right-hand side of an assignment, or is an actual in a call. | |
ee6ba406 | 5177 | |
0577b0b1 | 5178 | elsif Nkind (Expr) in N_Op then |
1d90d657 | 5179 | if Is_Floating_Point_Type (Typ) |
5180 | and then Validity_Check_Floating_Point | |
5181 | and then | |
5182 | (Nkind (Parent (Expr)) = N_Assignment_Statement | |
5183 | or else Nkind (Parent (Expr)) = N_Function_Call | |
5184 | or else Nkind (Parent (Expr)) = N_Parameter_Association) | |
5185 | then | |
5186 | return False; | |
5187 | else | |
5188 | return True; | |
5189 | end if; | |
5190 | ||
feff2f05 | 5191 | -- The result of a membership test is always valid, since it is true or |
5192 | -- false, there are no other possibilities. | |
0577b0b1 | 5193 | |
5194 | elsif Nkind (Expr) in N_Membership_Test then | |
5195 | return True; | |
5196 | ||
ee6ba406 | 5197 | -- For all other cases, we do not know the expression is valid |
5198 | ||
5199 | else | |
5200 | return False; | |
5201 | end if; | |
5202 | end Expr_Known_Valid; | |
5203 | ||
9dfe12ae | 5204 | ---------------- |
5205 | -- Find_Check -- | |
5206 | ---------------- | |
5207 | ||
5208 | procedure Find_Check | |
5209 | (Expr : Node_Id; | |
5210 | Check_Type : Character; | |
5211 | Target_Type : Entity_Id; | |
5212 | Entry_OK : out Boolean; | |
5213 | Check_Num : out Nat; | |
5214 | Ent : out Entity_Id; | |
5215 | Ofs : out Uint) | |
5216 | is | |
5217 | function Within_Range_Of | |
5218 | (Target_Type : Entity_Id; | |
314a23b6 | 5219 | Check_Type : Entity_Id) return Boolean; |
9dfe12ae | 5220 | -- Given a requirement for checking a range against Target_Type, and |
5221 | -- and a range Check_Type against which a check has already been made, | |
5222 | -- determines if the check against check type is sufficient to ensure | |
5223 | -- that no check against Target_Type is required. | |
5224 | ||
5225 | --------------------- | |
5226 | -- Within_Range_Of -- | |
5227 | --------------------- | |
5228 | ||
5229 | function Within_Range_Of | |
5230 | (Target_Type : Entity_Id; | |
314a23b6 | 5231 | Check_Type : Entity_Id) return Boolean |
9dfe12ae | 5232 | is |
5233 | begin | |
5234 | if Target_Type = Check_Type then | |
5235 | return True; | |
5236 | ||
5237 | else | |
5238 | declare | |
5239 | Tlo : constant Node_Id := Type_Low_Bound (Target_Type); | |
5240 | Thi : constant Node_Id := Type_High_Bound (Target_Type); | |
5241 | Clo : constant Node_Id := Type_Low_Bound (Check_Type); | |
5242 | Chi : constant Node_Id := Type_High_Bound (Check_Type); | |
5243 | ||
5244 | begin | |
5245 | if (Tlo = Clo | |
5246 | or else (Compile_Time_Known_Value (Tlo) | |
5247 | and then | |
5248 | Compile_Time_Known_Value (Clo) | |
5249 | and then | |
5250 | Expr_Value (Clo) >= Expr_Value (Tlo))) | |
5251 | and then | |
5252 | (Thi = Chi | |
5253 | or else (Compile_Time_Known_Value (Thi) | |
5254 | and then | |
5255 | Compile_Time_Known_Value (Chi) | |
5256 | and then | |
5257 | Expr_Value (Chi) <= Expr_Value (Clo))) | |
5258 | then | |
5259 | return True; | |
5260 | else | |
5261 | return False; | |
5262 | end if; | |
5263 | end; | |
5264 | end if; | |
5265 | end Within_Range_Of; | |
5266 | ||
5267 | -- Start of processing for Find_Check | |
5268 | ||
5269 | begin | |
ed195555 | 5270 | -- Establish default, in case no entry is found |
9dfe12ae | 5271 | |
5272 | Check_Num := 0; | |
5273 | ||
5274 | -- Case of expression is simple entity reference | |
5275 | ||
5276 | if Is_Entity_Name (Expr) then | |
5277 | Ent := Entity (Expr); | |
5278 | Ofs := Uint_0; | |
5279 | ||
5280 | -- Case of expression is entity + known constant | |
5281 | ||
5282 | elsif Nkind (Expr) = N_Op_Add | |
5283 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
5284 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
5285 | then | |
5286 | Ent := Entity (Left_Opnd (Expr)); | |
5287 | Ofs := Expr_Value (Right_Opnd (Expr)); | |
5288 | ||
5289 | -- Case of expression is entity - known constant | |
5290 | ||
5291 | elsif Nkind (Expr) = N_Op_Subtract | |
5292 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
5293 | and then Is_Entity_Name (Left_Opnd (Expr)) | |
5294 | then | |
5295 | Ent := Entity (Left_Opnd (Expr)); | |
5296 | Ofs := UI_Negate (Expr_Value (Right_Opnd (Expr))); | |
5297 | ||
5298 | -- Any other expression is not of the right form | |
5299 | ||
5300 | else | |
5301 | Ent := Empty; | |
5302 | Ofs := Uint_0; | |
5303 | Entry_OK := False; | |
5304 | return; | |
5305 | end if; | |
5306 | ||
feff2f05 | 5307 | -- Come here with expression of appropriate form, check if entity is an |
5308 | -- appropriate one for our purposes. | |
9dfe12ae | 5309 | |
5310 | if (Ekind (Ent) = E_Variable | |
cc60bd16 | 5311 | or else Is_Constant_Object (Ent)) |
9dfe12ae | 5312 | and then not Is_Library_Level_Entity (Ent) |
5313 | then | |
5314 | Entry_OK := True; | |
5315 | else | |
5316 | Entry_OK := False; | |
5317 | return; | |
5318 | end if; | |
5319 | ||
5320 | -- See if there is matching check already | |
5321 | ||
5322 | for J in reverse 1 .. Num_Saved_Checks loop | |
5323 | declare | |
5324 | SC : Saved_Check renames Saved_Checks (J); | |
5325 | ||
5326 | begin | |
5327 | if SC.Killed = False | |
5328 | and then SC.Entity = Ent | |
5329 | and then SC.Offset = Ofs | |
5330 | and then SC.Check_Type = Check_Type | |
5331 | and then Within_Range_Of (Target_Type, SC.Target_Type) | |
5332 | then | |
5333 | Check_Num := J; | |
5334 | return; | |
5335 | end if; | |
5336 | end; | |
5337 | end loop; | |
5338 | ||
5339 | -- If we fall through entry was not found | |
5340 | ||
9dfe12ae | 5341 | return; |
5342 | end Find_Check; | |
5343 | ||
5344 | --------------------------------- | |
5345 | -- Generate_Discriminant_Check -- | |
5346 | --------------------------------- | |
5347 | ||
5348 | -- Note: the code for this procedure is derived from the | |
feff2f05 | 5349 | -- Emit_Discriminant_Check Routine in trans.c. |
9dfe12ae | 5350 | |
5351 | procedure Generate_Discriminant_Check (N : Node_Id) is | |
5352 | Loc : constant Source_Ptr := Sloc (N); | |
5353 | Pref : constant Node_Id := Prefix (N); | |
5354 | Sel : constant Node_Id := Selector_Name (N); | |
5355 | ||
5356 | Orig_Comp : constant Entity_Id := | |
b6341c67 | 5357 | Original_Record_Component (Entity (Sel)); |
9dfe12ae | 5358 | -- The original component to be checked |
5359 | ||
5360 | Discr_Fct : constant Entity_Id := | |
b6341c67 | 5361 | Discriminant_Checking_Func (Orig_Comp); |
9dfe12ae | 5362 | -- The discriminant checking function |
5363 | ||
5364 | Discr : Entity_Id; | |
5365 | -- One discriminant to be checked in the type | |
5366 | ||
5367 | Real_Discr : Entity_Id; | |
5368 | -- Actual discriminant in the call | |
5369 | ||
5370 | Pref_Type : Entity_Id; | |
5371 | -- Type of relevant prefix (ignoring private/access stuff) | |
5372 | ||
5373 | Args : List_Id; | |
5374 | -- List of arguments for function call | |
5375 | ||
5376 | Formal : Entity_Id; | |
feff2f05 | 5377 | -- Keep track of the formal corresponding to the actual we build for |
5378 | -- each discriminant, in order to be able to perform the necessary type | |
5379 | -- conversions. | |
9dfe12ae | 5380 | |
5381 | Scomp : Node_Id; | |
5382 | -- Selected component reference for checking function argument | |
5383 | ||
5384 | begin | |
5385 | Pref_Type := Etype (Pref); | |
5386 | ||
5387 | -- Force evaluation of the prefix, so that it does not get evaluated | |
5388 | -- twice (once for the check, once for the actual reference). Such a | |
5389 | -- double evaluation is always a potential source of inefficiency, | |
5390 | -- and is functionally incorrect in the volatile case, or when the | |
5391 | -- prefix may have side-effects. An entity or a component of an | |
5392 | -- entity requires no evaluation. | |
5393 | ||
5394 | if Is_Entity_Name (Pref) then | |
5395 | if Treat_As_Volatile (Entity (Pref)) then | |
5396 | Force_Evaluation (Pref, Name_Req => True); | |
5397 | end if; | |
5398 | ||
5399 | elsif Treat_As_Volatile (Etype (Pref)) then | |
5400 | Force_Evaluation (Pref, Name_Req => True); | |
5401 | ||
5402 | elsif Nkind (Pref) = N_Selected_Component | |
5403 | and then Is_Entity_Name (Prefix (Pref)) | |
5404 | then | |
5405 | null; | |
5406 | ||
5407 | else | |
5408 | Force_Evaluation (Pref, Name_Req => True); | |
5409 | end if; | |
5410 | ||
5411 | -- For a tagged type, use the scope of the original component to | |
5412 | -- obtain the type, because ??? | |
5413 | ||
5414 | if Is_Tagged_Type (Scope (Orig_Comp)) then | |
5415 | Pref_Type := Scope (Orig_Comp); | |
5416 | ||
feff2f05 | 5417 | -- For an untagged derived type, use the discriminants of the parent |
5418 | -- which have been renamed in the derivation, possibly by a one-to-many | |
5419 | -- discriminant constraint. For non-tagged type, initially get the Etype | |
5420 | -- of the prefix | |
9dfe12ae | 5421 | |
5422 | else | |
5423 | if Is_Derived_Type (Pref_Type) | |
5424 | and then Number_Discriminants (Pref_Type) /= | |
5425 | Number_Discriminants (Etype (Base_Type (Pref_Type))) | |
5426 | then | |
5427 | Pref_Type := Etype (Base_Type (Pref_Type)); | |
5428 | end if; | |
5429 | end if; | |
5430 | ||
5431 | -- We definitely should have a checking function, This routine should | |
5432 | -- not be called if no discriminant checking function is present. | |
5433 | ||
5434 | pragma Assert (Present (Discr_Fct)); | |
5435 | ||
5436 | -- Create the list of the actual parameters for the call. This list | |
5437 | -- is the list of the discriminant fields of the record expression to | |
5438 | -- be discriminant checked. | |
5439 | ||
5440 | Args := New_List; | |
5441 | Formal := First_Formal (Discr_Fct); | |
5442 | Discr := First_Discriminant (Pref_Type); | |
5443 | while Present (Discr) loop | |
5444 | ||
5445 | -- If we have a corresponding discriminant field, and a parent | |
5446 | -- subtype is present, then we want to use the corresponding | |
5447 | -- discriminant since this is the one with the useful value. | |
5448 | ||
5449 | if Present (Corresponding_Discriminant (Discr)) | |
5450 | and then Ekind (Pref_Type) = E_Record_Type | |
5451 | and then Present (Parent_Subtype (Pref_Type)) | |
5452 | then | |
5453 | Real_Discr := Corresponding_Discriminant (Discr); | |
5454 | else | |
5455 | Real_Discr := Discr; | |
5456 | end if; | |
5457 | ||
5458 | -- Construct the reference to the discriminant | |
5459 | ||
5460 | Scomp := | |
5461 | Make_Selected_Component (Loc, | |
5462 | Prefix => | |
5463 | Unchecked_Convert_To (Pref_Type, | |
5464 | Duplicate_Subexpr (Pref)), | |
5465 | Selector_Name => New_Occurrence_Of (Real_Discr, Loc)); | |
5466 | ||
5467 | -- Manually analyze and resolve this selected component. We really | |
5468 | -- want it just as it appears above, and do not want the expander | |
feff2f05 | 5469 | -- playing discriminal games etc with this reference. Then we append |
5470 | -- the argument to the list we are gathering. | |
9dfe12ae | 5471 | |
5472 | Set_Etype (Scomp, Etype (Real_Discr)); | |
5473 | Set_Analyzed (Scomp, True); | |
5474 | Append_To (Args, Convert_To (Etype (Formal), Scomp)); | |
5475 | ||
5476 | Next_Formal_With_Extras (Formal); | |
5477 | Next_Discriminant (Discr); | |
5478 | end loop; | |
5479 | ||
5480 | -- Now build and insert the call | |
5481 | ||
5482 | Insert_Action (N, | |
5483 | Make_Raise_Constraint_Error (Loc, | |
5484 | Condition => | |
5485 | Make_Function_Call (Loc, | |
5486 | Name => New_Occurrence_Of (Discr_Fct, Loc), | |
5487 | Parameter_Associations => Args), | |
5488 | Reason => CE_Discriminant_Check_Failed)); | |
5489 | end Generate_Discriminant_Check; | |
5490 | ||
5c99c290 | 5491 | --------------------------- |
5492 | -- Generate_Index_Checks -- | |
5493 | --------------------------- | |
9dfe12ae | 5494 | |
5495 | procedure Generate_Index_Checks (N : Node_Id) is | |
05f3e139 | 5496 | |
5497 | function Entity_Of_Prefix return Entity_Id; | |
5498 | -- Returns the entity of the prefix of N (or Empty if not found) | |
5499 | ||
3f42e2a7 | 5500 | ---------------------- |
5501 | -- Entity_Of_Prefix -- | |
5502 | ---------------------- | |
5503 | ||
05f3e139 | 5504 | function Entity_Of_Prefix return Entity_Id is |
e5d38095 | 5505 | P : Node_Id; |
5506 | ||
05f3e139 | 5507 | begin |
e5d38095 | 5508 | P := Prefix (N); |
05f3e139 | 5509 | while not Is_Entity_Name (P) loop |
5510 | if not Nkind_In (P, N_Selected_Component, | |
5511 | N_Indexed_Component) | |
5512 | then | |
5513 | return Empty; | |
5514 | end if; | |
5515 | ||
5516 | P := Prefix (P); | |
5517 | end loop; | |
5518 | ||
5519 | return Entity (P); | |
5520 | end Entity_Of_Prefix; | |
5521 | ||
5522 | -- Local variables | |
5523 | ||
5524 | Loc : constant Source_Ptr := Sloc (N); | |
5525 | A : constant Node_Id := Prefix (N); | |
5526 | A_Ent : constant Entity_Id := Entity_Of_Prefix; | |
5527 | Sub : Node_Id; | |
9dfe12ae | 5528 | |
3f42e2a7 | 5529 | -- Start of processing for Generate_Index_Checks |
5530 | ||
9dfe12ae | 5531 | begin |
05f3e139 | 5532 | -- Ignore call if the prefix is not an array since we have a serious |
5533 | -- error in the sources. Ignore it also if index checks are suppressed | |
5534 | -- for array object or type. | |
0577b0b1 | 5535 | |
05f3e139 | 5536 | if not Is_Array_Type (Etype (A)) |
5537 | or else (Present (A_Ent) | |
e5d38095 | 5538 | and then Index_Checks_Suppressed (A_Ent)) |
0577b0b1 | 5539 | or else Index_Checks_Suppressed (Etype (A)) |
5540 | then | |
5541 | return; | |
df9fba45 | 5542 | |
5543 | -- The indexed component we are dealing with contains 'Loop_Entry in its | |
5544 | -- prefix. This case arises when analysis has determined that constructs | |
5545 | -- such as | |
5546 | ||
5547 | -- Prefix'Loop_Entry (Expr) | |
5548 | -- Prefix'Loop_Entry (Expr1, Expr2, ... ExprN) | |
5549 | ||
5550 | -- require rewriting for error detection purposes. A side effect of this | |
5551 | -- action is the generation of index checks that mention 'Loop_Entry. | |
5552 | -- Delay the generation of the check until 'Loop_Entry has been properly | |
5553 | -- expanded. This is done in Expand_Loop_Entry_Attributes. | |
5554 | ||
5555 | elsif Nkind (Prefix (N)) = N_Attribute_Reference | |
5556 | and then Attribute_Name (Prefix (N)) = Name_Loop_Entry | |
5557 | then | |
5558 | return; | |
0577b0b1 | 5559 | end if; |
5560 | ||
05f3e139 | 5561 | -- Generate a raise of constraint error with the appropriate reason and |
5562 | -- a condition of the form: | |
5563 | ||
3f42e2a7 | 5564 | -- Base_Type (Sub) not in Array'Range (Subscript) |
05f3e139 | 5565 | |
5566 | -- Note that the reason we generate the conversion to the base type here | |
5567 | -- is that we definitely want the range check to take place, even if it | |
5568 | -- looks like the subtype is OK. Optimization considerations that allow | |
5569 | -- us to omit the check have already been taken into account in the | |
5570 | -- setting of the Do_Range_Check flag earlier on. | |
0577b0b1 | 5571 | |
9dfe12ae | 5572 | Sub := First (Expressions (N)); |
05f3e139 | 5573 | |
5574 | -- Handle string literals | |
5575 | ||
5576 | if Ekind (Etype (A)) = E_String_Literal_Subtype then | |
9dfe12ae | 5577 | if Do_Range_Check (Sub) then |
5578 | Set_Do_Range_Check (Sub, False); | |
5579 | ||
05f3e139 | 5580 | -- For string literals we obtain the bounds of the string from the |
5581 | -- associated subtype. | |
9dfe12ae | 5582 | |
05f3e139 | 5583 | Insert_Action (N, |
094ed68e | 5584 | Make_Raise_Constraint_Error (Loc, |
5585 | Condition => | |
5586 | Make_Not_In (Loc, | |
5587 | Left_Opnd => | |
5588 | Convert_To (Base_Type (Etype (Sub)), | |
5589 | Duplicate_Subexpr_Move_Checks (Sub)), | |
5590 | Right_Opnd => | |
5591 | Make_Attribute_Reference (Loc, | |
5592 | Prefix => New_Reference_To (Etype (A), Loc), | |
5593 | Attribute_Name => Name_Range)), | |
5594 | Reason => CE_Index_Check_Failed)); | |
05f3e139 | 5595 | end if; |
9dfe12ae | 5596 | |
05f3e139 | 5597 | -- General case |
9dfe12ae | 5598 | |
05f3e139 | 5599 | else |
5600 | declare | |
5601 | A_Idx : Node_Id := Empty; | |
5602 | A_Range : Node_Id; | |
5603 | Ind : Nat; | |
5604 | Num : List_Id; | |
5605 | Range_N : Node_Id; | |
9dfe12ae | 5606 | |
05f3e139 | 5607 | begin |
5608 | A_Idx := First_Index (Etype (A)); | |
5609 | Ind := 1; | |
5610 | while Present (Sub) loop | |
5611 | if Do_Range_Check (Sub) then | |
5612 | Set_Do_Range_Check (Sub, False); | |
9dfe12ae | 5613 | |
05f3e139 | 5614 | -- Force evaluation except for the case of a simple name of |
5615 | -- a non-volatile entity. | |
9dfe12ae | 5616 | |
05f3e139 | 5617 | if not Is_Entity_Name (Sub) |
5618 | or else Treat_As_Volatile (Entity (Sub)) | |
5619 | then | |
5620 | Force_Evaluation (Sub); | |
5621 | end if; | |
9dfe12ae | 5622 | |
05f3e139 | 5623 | if Nkind (A_Idx) = N_Range then |
5624 | A_Range := A_Idx; | |
5625 | ||
5626 | elsif Nkind (A_Idx) = N_Identifier | |
5627 | or else Nkind (A_Idx) = N_Expanded_Name | |
5628 | then | |
5629 | A_Range := Scalar_Range (Entity (A_Idx)); | |
5630 | ||
5631 | else pragma Assert (Nkind (A_Idx) = N_Subtype_Indication); | |
5632 | A_Range := Range_Expression (Constraint (A_Idx)); | |
5633 | end if; | |
5634 | ||
5635 | -- For array objects with constant bounds we can generate | |
5636 | -- the index check using the bounds of the type of the index | |
5637 | ||
5638 | if Present (A_Ent) | |
5639 | and then Ekind (A_Ent) = E_Variable | |
5640 | and then Is_Constant_Bound (Low_Bound (A_Range)) | |
5641 | and then Is_Constant_Bound (High_Bound (A_Range)) | |
5642 | then | |
5643 | Range_N := | |
5644 | Make_Attribute_Reference (Loc, | |
3f42e2a7 | 5645 | Prefix => |
5646 | New_Reference_To (Etype (A_Idx), Loc), | |
05f3e139 | 5647 | Attribute_Name => Name_Range); |
5648 | ||
5649 | -- For arrays with non-constant bounds we cannot generate | |
5650 | -- the index check using the bounds of the type of the index | |
5651 | -- since it may reference discriminants of some enclosing | |
5652 | -- type. We obtain the bounds directly from the prefix | |
5653 | -- object. | |
5654 | ||
5655 | else | |
5656 | if Ind = 1 then | |
5657 | Num := No_List; | |
5658 | else | |
5659 | Num := New_List (Make_Integer_Literal (Loc, Ind)); | |
5660 | end if; | |
5661 | ||
5662 | Range_N := | |
5663 | Make_Attribute_Reference (Loc, | |
5664 | Prefix => | |
5665 | Duplicate_Subexpr_Move_Checks (A, Name_Req => True), | |
5666 | Attribute_Name => Name_Range, | |
5667 | Expressions => Num); | |
5668 | end if; | |
5669 | ||
5670 | Insert_Action (N, | |
094ed68e | 5671 | Make_Raise_Constraint_Error (Loc, |
5672 | Condition => | |
5673 | Make_Not_In (Loc, | |
5674 | Left_Opnd => | |
5675 | Convert_To (Base_Type (Etype (Sub)), | |
5676 | Duplicate_Subexpr_Move_Checks (Sub)), | |
5677 | Right_Opnd => Range_N), | |
5678 | Reason => CE_Index_Check_Failed)); | |
05f3e139 | 5679 | end if; |
5680 | ||
5681 | A_Idx := Next_Index (A_Idx); | |
5682 | Ind := Ind + 1; | |
5683 | Next (Sub); | |
5684 | end loop; | |
5685 | end; | |
5686 | end if; | |
9dfe12ae | 5687 | end Generate_Index_Checks; |
5688 | ||
5689 | -------------------------- | |
5690 | -- Generate_Range_Check -- | |
5691 | -------------------------- | |
5692 | ||
5693 | procedure Generate_Range_Check | |
5694 | (N : Node_Id; | |
5695 | Target_Type : Entity_Id; | |
5696 | Reason : RT_Exception_Code) | |
5697 | is | |
5698 | Loc : constant Source_Ptr := Sloc (N); | |
5699 | Source_Type : constant Entity_Id := Etype (N); | |
5700 | Source_Base_Type : constant Entity_Id := Base_Type (Source_Type); | |
5701 | Target_Base_Type : constant Entity_Id := Base_Type (Target_Type); | |
5702 | ||
5703 | begin | |
feff2f05 | 5704 | -- First special case, if the source type is already within the range |
5705 | -- of the target type, then no check is needed (probably we should have | |
5706 | -- stopped Do_Range_Check from being set in the first place, but better | |
b40670e1 | 5707 | -- late than never in preventing junk code! |
9dfe12ae | 5708 | |
7a1dabb3 | 5709 | if In_Subrange_Of (Source_Type, Target_Type) |
b40670e1 | 5710 | |
5711 | -- We do NOT apply this if the source node is a literal, since in this | |
5712 | -- case the literal has already been labeled as having the subtype of | |
5713 | -- the target. | |
5714 | ||
9dfe12ae | 5715 | and then not |
b40670e1 | 5716 | (Nkind_In (N, N_Integer_Literal, N_Real_Literal, N_Character_Literal) |
9dfe12ae | 5717 | or else |
b40670e1 | 5718 | (Is_Entity_Name (N) |
5719 | and then Ekind (Entity (N)) = E_Enumeration_Literal)) | |
5720 | ||
5721 | -- Also do not apply this for floating-point if Check_Float_Overflow | |
5722 | ||
5723 | and then not | |
5724 | (Is_Floating_Point_Type (Source_Type) and Check_Float_Overflow) | |
9dfe12ae | 5725 | then |
5726 | return; | |
5727 | end if; | |
5728 | ||
5729 | -- We need a check, so force evaluation of the node, so that it does | |
5730 | -- not get evaluated twice (once for the check, once for the actual | |
5731 | -- reference). Such a double evaluation is always a potential source | |
5732 | -- of inefficiency, and is functionally incorrect in the volatile case. | |
5733 | ||
b40670e1 | 5734 | if not Is_Entity_Name (N) or else Treat_As_Volatile (Entity (N)) then |
9dfe12ae | 5735 | Force_Evaluation (N); |
5736 | end if; | |
5737 | ||
feff2f05 | 5738 | -- The easiest case is when Source_Base_Type and Target_Base_Type are |
5739 | -- the same since in this case we can simply do a direct check of the | |
5740 | -- value of N against the bounds of Target_Type. | |
9dfe12ae | 5741 | |
5742 | -- [constraint_error when N not in Target_Type] | |
5743 | ||
5744 | -- Note: this is by far the most common case, for example all cases of | |
5745 | -- checks on the RHS of assignments are in this category, but not all | |
5746 | -- cases are like this. Notably conversions can involve two types. | |
5747 | ||
5748 | if Source_Base_Type = Target_Base_Type then | |
5749 | Insert_Action (N, | |
5750 | Make_Raise_Constraint_Error (Loc, | |
5751 | Condition => | |
5752 | Make_Not_In (Loc, | |
5753 | Left_Opnd => Duplicate_Subexpr (N), | |
5754 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
5755 | Reason => Reason)); | |
5756 | ||
5757 | -- Next test for the case where the target type is within the bounds | |
5758 | -- of the base type of the source type, since in this case we can | |
5759 | -- simply convert these bounds to the base type of T to do the test. | |
5760 | ||
5761 | -- [constraint_error when N not in | |
5762 | -- Source_Base_Type (Target_Type'First) | |
5763 | -- .. | |
5764 | -- Source_Base_Type(Target_Type'Last))] | |
5765 | ||
f2a06be9 | 5766 | -- The conversions will always work and need no check |
9dfe12ae | 5767 | |
a9b57347 | 5768 | -- Unchecked_Convert_To is used instead of Convert_To to handle the case |
5769 | -- of converting from an enumeration value to an integer type, such as | |
5770 | -- occurs for the case of generating a range check on Enum'Val(Exp) | |
5771 | -- (which used to be handled by gigi). This is OK, since the conversion | |
5772 | -- itself does not require a check. | |
5773 | ||
7a1dabb3 | 5774 | elsif In_Subrange_Of (Target_Type, Source_Base_Type) then |
9dfe12ae | 5775 | Insert_Action (N, |
5776 | Make_Raise_Constraint_Error (Loc, | |
5777 | Condition => | |
5778 | Make_Not_In (Loc, | |
5779 | Left_Opnd => Duplicate_Subexpr (N), | |
5780 | ||
5781 | Right_Opnd => | |
5782 | Make_Range (Loc, | |
5783 | Low_Bound => | |
a9b57347 | 5784 | Unchecked_Convert_To (Source_Base_Type, |
9dfe12ae | 5785 | Make_Attribute_Reference (Loc, |
5786 | Prefix => | |
5787 | New_Occurrence_Of (Target_Type, Loc), | |
5788 | Attribute_Name => Name_First)), | |
5789 | ||
5790 | High_Bound => | |
a9b57347 | 5791 | Unchecked_Convert_To (Source_Base_Type, |
9dfe12ae | 5792 | Make_Attribute_Reference (Loc, |
5793 | Prefix => | |
5794 | New_Occurrence_Of (Target_Type, Loc), | |
5795 | Attribute_Name => Name_Last)))), | |
5796 | Reason => Reason)); | |
5797 | ||
feff2f05 | 5798 | -- Note that at this stage we now that the Target_Base_Type is not in |
5799 | -- the range of the Source_Base_Type (since even the Target_Type itself | |
5800 | -- is not in this range). It could still be the case that Source_Type is | |
5801 | -- in range of the target base type since we have not checked that case. | |
9dfe12ae | 5802 | |
feff2f05 | 5803 | -- If that is the case, we can freely convert the source to the target, |
5804 | -- and then test the target result against the bounds. | |
9dfe12ae | 5805 | |
7a1dabb3 | 5806 | elsif In_Subrange_Of (Source_Type, Target_Base_Type) then |
9dfe12ae | 5807 | |
feff2f05 | 5808 | -- We make a temporary to hold the value of the converted value |
5809 | -- (converted to the base type), and then we will do the test against | |
5810 | -- this temporary. | |
9dfe12ae | 5811 | |
5812 | -- Tnn : constant Target_Base_Type := Target_Base_Type (N); | |
5813 | -- [constraint_error when Tnn not in Target_Type] | |
5814 | ||
5815 | -- Then the conversion itself is replaced by an occurrence of Tnn | |
5816 | ||
5817 | declare | |
46eb6933 | 5818 | Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
9dfe12ae | 5819 | |
5820 | begin | |
5821 | Insert_Actions (N, New_List ( | |
5822 | Make_Object_Declaration (Loc, | |
5823 | Defining_Identifier => Tnn, | |
5824 | Object_Definition => | |
5825 | New_Occurrence_Of (Target_Base_Type, Loc), | |
5826 | Constant_Present => True, | |
5827 | Expression => | |
5828 | Make_Type_Conversion (Loc, | |
5829 | Subtype_Mark => New_Occurrence_Of (Target_Base_Type, Loc), | |
5830 | Expression => Duplicate_Subexpr (N))), | |
5831 | ||
5832 | Make_Raise_Constraint_Error (Loc, | |
5833 | Condition => | |
5834 | Make_Not_In (Loc, | |
5835 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
5836 | Right_Opnd => New_Occurrence_Of (Target_Type, Loc)), | |
5837 | ||
5838 | Reason => Reason))); | |
5839 | ||
5840 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
2af58f67 | 5841 | |
5842 | -- Set the type of N, because the declaration for Tnn might not | |
5843 | -- be analyzed yet, as is the case if N appears within a record | |
5844 | -- declaration, as a discriminant constraint or expression. | |
5845 | ||
5846 | Set_Etype (N, Target_Base_Type); | |
9dfe12ae | 5847 | end; |
5848 | ||
5849 | -- At this stage, we know that we have two scalar types, which are | |
5850 | -- directly convertible, and where neither scalar type has a base | |
5851 | -- range that is in the range of the other scalar type. | |
5852 | ||
5853 | -- The only way this can happen is with a signed and unsigned type. | |
5854 | -- So test for these two cases: | |
5855 | ||
5856 | else | |
5857 | -- Case of the source is unsigned and the target is signed | |
5858 | ||
5859 | if Is_Unsigned_Type (Source_Base_Type) | |
5860 | and then not Is_Unsigned_Type (Target_Base_Type) | |
5861 | then | |
5862 | -- If the source is unsigned and the target is signed, then we | |
5863 | -- know that the source is not shorter than the target (otherwise | |
5864 | -- the source base type would be in the target base type range). | |
5865 | ||
feff2f05 | 5866 | -- In other words, the unsigned type is either the same size as |
5867 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 5868 | |
5869 | pragma Assert | |
5870 | (Esize (Source_Base_Type) >= Esize (Target_Base_Type)); | |
5871 | ||
5872 | -- We only need to check the low bound if the low bound of the | |
5873 | -- target type is non-negative. If the low bound of the target | |
5874 | -- type is negative, then we know that we will fit fine. | |
5875 | ||
5876 | -- If the high bound of the target type is negative, then we | |
5877 | -- know we have a constraint error, since we can't possibly | |
5878 | -- have a negative source. | |
5879 | ||
5880 | -- With these two checks out of the way, we can do the check | |
5881 | -- using the source type safely | |
5882 | ||
5883 | -- This is definitely the most annoying case! | |
5884 | ||
5885 | -- [constraint_error | |
5886 | -- when (Target_Type'First >= 0 | |
5887 | -- and then | |
5888 | -- N < Source_Base_Type (Target_Type'First)) | |
5889 | -- or else Target_Type'Last < 0 | |
5890 | -- or else N > Source_Base_Type (Target_Type'Last)]; | |
5891 | ||
5892 | -- We turn off all checks since we know that the conversions | |
5893 | -- will work fine, given the guards for negative values. | |
5894 | ||
5895 | Insert_Action (N, | |
5896 | Make_Raise_Constraint_Error (Loc, | |
5897 | Condition => | |
5898 | Make_Or_Else (Loc, | |
5899 | Make_Or_Else (Loc, | |
5900 | Left_Opnd => | |
5901 | Make_And_Then (Loc, | |
5902 | Left_Opnd => Make_Op_Ge (Loc, | |
5903 | Left_Opnd => | |
5904 | Make_Attribute_Reference (Loc, | |
5905 | Prefix => | |
5906 | New_Occurrence_Of (Target_Type, Loc), | |
5907 | Attribute_Name => Name_First), | |
5908 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
5909 | ||
5910 | Right_Opnd => | |
5911 | Make_Op_Lt (Loc, | |
5912 | Left_Opnd => Duplicate_Subexpr (N), | |
5913 | Right_Opnd => | |
5914 | Convert_To (Source_Base_Type, | |
5915 | Make_Attribute_Reference (Loc, | |
5916 | Prefix => | |
5917 | New_Occurrence_Of (Target_Type, Loc), | |
5918 | Attribute_Name => Name_First)))), | |
5919 | ||
5920 | Right_Opnd => | |
5921 | Make_Op_Lt (Loc, | |
5922 | Left_Opnd => | |
5923 | Make_Attribute_Reference (Loc, | |
5924 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
5925 | Attribute_Name => Name_Last), | |
5926 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0))), | |
5927 | ||
5928 | Right_Opnd => | |
5929 | Make_Op_Gt (Loc, | |
5930 | Left_Opnd => Duplicate_Subexpr (N), | |
5931 | Right_Opnd => | |
5932 | Convert_To (Source_Base_Type, | |
5933 | Make_Attribute_Reference (Loc, | |
5934 | Prefix => New_Occurrence_Of (Target_Type, Loc), | |
5935 | Attribute_Name => Name_Last)))), | |
5936 | ||
5937 | Reason => Reason), | |
5938 | Suppress => All_Checks); | |
5939 | ||
5940 | -- Only remaining possibility is that the source is signed and | |
fc75802a | 5941 | -- the target is unsigned. |
9dfe12ae | 5942 | |
5943 | else | |
5944 | pragma Assert (not Is_Unsigned_Type (Source_Base_Type) | |
5945 | and then Is_Unsigned_Type (Target_Base_Type)); | |
5946 | ||
feff2f05 | 5947 | -- If the source is signed and the target is unsigned, then we |
5948 | -- know that the target is not shorter than the source (otherwise | |
5949 | -- the target base type would be in the source base type range). | |
9dfe12ae | 5950 | |
feff2f05 | 5951 | -- In other words, the unsigned type is either the same size as |
5952 | -- the target, or it is larger. It cannot be smaller. | |
9dfe12ae | 5953 | |
feff2f05 | 5954 | -- Clearly we have an error if the source value is negative since |
5955 | -- no unsigned type can have negative values. If the source type | |
5956 | -- is non-negative, then the check can be done using the target | |
5957 | -- type. | |
9dfe12ae | 5958 | |
5959 | -- Tnn : constant Target_Base_Type (N) := Target_Type; | |
5960 | ||
5961 | -- [constraint_error | |
5962 | -- when N < 0 or else Tnn not in Target_Type]; | |
5963 | ||
feff2f05 | 5964 | -- We turn off all checks for the conversion of N to the target |
5965 | -- base type, since we generate the explicit check to ensure that | |
5966 | -- the value is non-negative | |
9dfe12ae | 5967 | |
5968 | declare | |
46eb6933 | 5969 | Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N); |
9dfe12ae | 5970 | |
5971 | begin | |
5972 | Insert_Actions (N, New_List ( | |
5973 | Make_Object_Declaration (Loc, | |
5974 | Defining_Identifier => Tnn, | |
5975 | Object_Definition => | |
5976 | New_Occurrence_Of (Target_Base_Type, Loc), | |
5977 | Constant_Present => True, | |
5978 | Expression => | |
a9b57347 | 5979 | Make_Unchecked_Type_Conversion (Loc, |
9dfe12ae | 5980 | Subtype_Mark => |
5981 | New_Occurrence_Of (Target_Base_Type, Loc), | |
5982 | Expression => Duplicate_Subexpr (N))), | |
5983 | ||
5984 | Make_Raise_Constraint_Error (Loc, | |
5985 | Condition => | |
5986 | Make_Or_Else (Loc, | |
5987 | Left_Opnd => | |
5988 | Make_Op_Lt (Loc, | |
5989 | Left_Opnd => Duplicate_Subexpr (N), | |
5990 | Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), | |
5991 | ||
5992 | Right_Opnd => | |
5993 | Make_Not_In (Loc, | |
5994 | Left_Opnd => New_Occurrence_Of (Tnn, Loc), | |
5995 | Right_Opnd => | |
5996 | New_Occurrence_Of (Target_Type, Loc))), | |
5997 | ||
5998 | Reason => Reason)), | |
5999 | Suppress => All_Checks); | |
6000 | ||
feff2f05 | 6001 | -- Set the Etype explicitly, because Insert_Actions may have |
6002 | -- placed the declaration in the freeze list for an enclosing | |
6003 | -- construct, and thus it is not analyzed yet. | |
9dfe12ae | 6004 | |
6005 | Set_Etype (Tnn, Target_Base_Type); | |
6006 | Rewrite (N, New_Occurrence_Of (Tnn, Loc)); | |
6007 | end; | |
6008 | end if; | |
6009 | end if; | |
6010 | end Generate_Range_Check; | |
6011 | ||
2af58f67 | 6012 | ------------------ |
6013 | -- Get_Check_Id -- | |
6014 | ------------------ | |
6015 | ||
6016 | function Get_Check_Id (N : Name_Id) return Check_Id is | |
6017 | begin | |
6018 | -- For standard check name, we can do a direct computation | |
6019 | ||
6020 | if N in First_Check_Name .. Last_Check_Name then | |
6021 | return Check_Id (N - (First_Check_Name - 1)); | |
6022 | ||
6023 | -- For non-standard names added by pragma Check_Name, search table | |
6024 | ||
6025 | else | |
6026 | for J in All_Checks + 1 .. Check_Names.Last loop | |
6027 | if Check_Names.Table (J) = N then | |
6028 | return J; | |
6029 | end if; | |
6030 | end loop; | |
6031 | end if; | |
6032 | ||
6033 | -- No matching name found | |
6034 | ||
6035 | return No_Check_Id; | |
6036 | end Get_Check_Id; | |
6037 | ||
ee6ba406 | 6038 | --------------------- |
6039 | -- Get_Discriminal -- | |
6040 | --------------------- | |
6041 | ||
6042 | function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is | |
6043 | Loc : constant Source_Ptr := Sloc (E); | |
6044 | D : Entity_Id; | |
6045 | Sc : Entity_Id; | |
6046 | ||
6047 | begin | |
0577b0b1 | 6048 | -- The bound can be a bona fide parameter of a protected operation, |
6049 | -- rather than a prival encoded as an in-parameter. | |
6050 | ||
6051 | if No (Discriminal_Link (Entity (Bound))) then | |
6052 | return Bound; | |
6053 | end if; | |
6054 | ||
2af58f67 | 6055 | -- Climb the scope stack looking for an enclosing protected type. If |
6056 | -- we run out of scopes, return the bound itself. | |
6057 | ||
6058 | Sc := Scope (E); | |
6059 | while Present (Sc) loop | |
6060 | if Sc = Standard_Standard then | |
6061 | return Bound; | |
6062 | ||
6063 | elsif Ekind (Sc) = E_Protected_Type then | |
6064 | exit; | |
6065 | end if; | |
6066 | ||
6067 | Sc := Scope (Sc); | |
6068 | end loop; | |
6069 | ||
ee6ba406 | 6070 | D := First_Discriminant (Sc); |
2af58f67 | 6071 | while Present (D) loop |
6072 | if Chars (D) = Chars (Bound) then | |
6073 | return New_Occurrence_Of (Discriminal (D), Loc); | |
6074 | end if; | |
ee6ba406 | 6075 | |
ee6ba406 | 6076 | Next_Discriminant (D); |
6077 | end loop; | |
6078 | ||
2af58f67 | 6079 | return Bound; |
ee6ba406 | 6080 | end Get_Discriminal; |
6081 | ||
2af58f67 | 6082 | ---------------------- |
6083 | -- Get_Range_Checks -- | |
6084 | ---------------------- | |
6085 | ||
6086 | function Get_Range_Checks | |
6087 | (Ck_Node : Node_Id; | |
6088 | Target_Typ : Entity_Id; | |
6089 | Source_Typ : Entity_Id := Empty; | |
6090 | Warn_Node : Node_Id := Empty) return Check_Result | |
6091 | is | |
6092 | begin | |
6093 | return Selected_Range_Checks | |
6094 | (Ck_Node, Target_Typ, Source_Typ, Warn_Node); | |
6095 | end Get_Range_Checks; | |
6096 | ||
ee6ba406 | 6097 | ------------------ |
6098 | -- Guard_Access -- | |
6099 | ------------------ | |
6100 | ||
6101 | function Guard_Access | |
6102 | (Cond : Node_Id; | |
6103 | Loc : Source_Ptr; | |
314a23b6 | 6104 | Ck_Node : Node_Id) return Node_Id |
ee6ba406 | 6105 | is |
6106 | begin | |
6107 | if Nkind (Cond) = N_Or_Else then | |
6108 | Set_Paren_Count (Cond, 1); | |
6109 | end if; | |
6110 | ||
6111 | if Nkind (Ck_Node) = N_Allocator then | |
6112 | return Cond; | |
6113 | else | |
6114 | return | |
6115 | Make_And_Then (Loc, | |
6116 | Left_Opnd => | |
6117 | Make_Op_Ne (Loc, | |
9dfe12ae | 6118 | Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node), |
ee6ba406 | 6119 | Right_Opnd => Make_Null (Loc)), |
6120 | Right_Opnd => Cond); | |
6121 | end if; | |
6122 | end Guard_Access; | |
6123 | ||
6124 | ----------------------------- | |
6125 | -- Index_Checks_Suppressed -- | |
6126 | ----------------------------- | |
6127 | ||
6128 | function Index_Checks_Suppressed (E : Entity_Id) return Boolean is | |
6129 | begin | |
9dfe12ae | 6130 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
6131 | return Is_Check_Suppressed (E, Index_Check); | |
6132 | else | |
fafc6b97 | 6133 | return Scope_Suppress.Suppress (Index_Check); |
9dfe12ae | 6134 | end if; |
ee6ba406 | 6135 | end Index_Checks_Suppressed; |
6136 | ||
6137 | ---------------- | |
6138 | -- Initialize -- | |
6139 | ---------------- | |
6140 | ||
6141 | procedure Initialize is | |
6142 | begin | |
6143 | for J in Determine_Range_Cache_N'Range loop | |
6144 | Determine_Range_Cache_N (J) := Empty; | |
6145 | end loop; | |
2af58f67 | 6146 | |
6147 | Check_Names.Init; | |
6148 | ||
6149 | for J in Int range 1 .. All_Checks loop | |
6150 | Check_Names.Append (Name_Id (Int (First_Check_Name) + J - 1)); | |
6151 | end loop; | |
ee6ba406 | 6152 | end Initialize; |
6153 | ||
6154 | ------------------------- | |
6155 | -- Insert_Range_Checks -- | |
6156 | ------------------------- | |
6157 | ||
6158 | procedure Insert_Range_Checks | |
6159 | (Checks : Check_Result; | |
6160 | Node : Node_Id; | |
6161 | Suppress_Typ : Entity_Id; | |
6162 | Static_Sloc : Source_Ptr := No_Location; | |
6163 | Flag_Node : Node_Id := Empty; | |
6164 | Do_Before : Boolean := False) | |
6165 | is | |
6166 | Internal_Flag_Node : Node_Id := Flag_Node; | |
6167 | Internal_Static_Sloc : Source_Ptr := Static_Sloc; | |
6168 | ||
6169 | Check_Node : Node_Id; | |
6170 | Checks_On : constant Boolean := | |
b6341c67 | 6171 | (not Index_Checks_Suppressed (Suppress_Typ)) |
6172 | or else (not Range_Checks_Suppressed (Suppress_Typ)); | |
ee6ba406 | 6173 | |
6174 | begin | |
feff2f05 | 6175 | -- For now we just return if Checks_On is false, however this should be |
6176 | -- enhanced to check for an always True value in the condition and to | |
6177 | -- generate a compilation warning??? | |
ee6ba406 | 6178 | |
6dbcfcd9 | 6179 | if not Full_Expander_Active or else not Checks_On then |
ee6ba406 | 6180 | return; |
6181 | end if; | |
6182 | ||
6183 | if Static_Sloc = No_Location then | |
6184 | Internal_Static_Sloc := Sloc (Node); | |
6185 | end if; | |
6186 | ||
6187 | if No (Flag_Node) then | |
6188 | Internal_Flag_Node := Node; | |
6189 | end if; | |
6190 | ||
6191 | for J in 1 .. 2 loop | |
6192 | exit when No (Checks (J)); | |
6193 | ||
6194 | if Nkind (Checks (J)) = N_Raise_Constraint_Error | |
6195 | and then Present (Condition (Checks (J))) | |
6196 | then | |
6197 | if not Has_Dynamic_Range_Check (Internal_Flag_Node) then | |
6198 | Check_Node := Checks (J); | |
6199 | Mark_Rewrite_Insertion (Check_Node); | |
6200 | ||
6201 | if Do_Before then | |
6202 | Insert_Before_And_Analyze (Node, Check_Node); | |
6203 | else | |
6204 | Insert_After_And_Analyze (Node, Check_Node); | |
6205 | end if; | |
6206 | ||
6207 | Set_Has_Dynamic_Range_Check (Internal_Flag_Node); | |
6208 | end if; | |
6209 | ||
6210 | else | |
6211 | Check_Node := | |
f15731c4 | 6212 | Make_Raise_Constraint_Error (Internal_Static_Sloc, |
6213 | Reason => CE_Range_Check_Failed); | |
ee6ba406 | 6214 | Mark_Rewrite_Insertion (Check_Node); |
6215 | ||
6216 | if Do_Before then | |
6217 | Insert_Before_And_Analyze (Node, Check_Node); | |
6218 | else | |
6219 | Insert_After_And_Analyze (Node, Check_Node); | |
6220 | end if; | |
6221 | end if; | |
6222 | end loop; | |
6223 | end Insert_Range_Checks; | |
6224 | ||
6225 | ------------------------ | |
6226 | -- Insert_Valid_Check -- | |
6227 | ------------------------ | |
6228 | ||
6229 | procedure Insert_Valid_Check (Expr : Node_Id) is | |
6230 | Loc : constant Source_Ptr := Sloc (Expr); | |
70580828 | 6231 | Typ : constant Entity_Id := Etype (Expr); |
8b718dab | 6232 | Exp : Node_Id; |
ee6ba406 | 6233 | |
6234 | begin | |
06ad5813 | 6235 | -- Do not insert if checks off, or if not checking validity or |
6236 | -- if expression is known to be valid | |
ee6ba406 | 6237 | |
0577b0b1 | 6238 | if not Validity_Checks_On |
6239 | or else Range_Or_Validity_Checks_Suppressed (Expr) | |
06ad5813 | 6240 | or else Expr_Known_Valid (Expr) |
ee6ba406 | 6241 | then |
8b718dab | 6242 | return; |
6243 | end if; | |
ee6ba406 | 6244 | |
70580828 | 6245 | -- Do not insert checks within a predicate function. This will arise |
6246 | -- if the current unit and the predicate function are being compiled | |
6247 | -- with validity checks enabled. | |
6248 | ||
6249 | if Present (Predicate_Function (Typ)) | |
6250 | and then Current_Scope = Predicate_Function (Typ) | |
6251 | then | |
6252 | return; | |
6253 | end if; | |
6254 | ||
8b718dab | 6255 | -- If we have a checked conversion, then validity check applies to |
6256 | -- the expression inside the conversion, not the result, since if | |
6257 | -- the expression inside is valid, then so is the conversion result. | |
ee6ba406 | 6258 | |
8b718dab | 6259 | Exp := Expr; |
6260 | while Nkind (Exp) = N_Type_Conversion loop | |
6261 | Exp := Expression (Exp); | |
6262 | end loop; | |
6263 | ||
0577b0b1 | 6264 | -- We are about to insert the validity check for Exp. We save and |
6265 | -- reset the Do_Range_Check flag over this validity check, and then | |
6266 | -- put it back for the final original reference (Exp may be rewritten). | |
6267 | ||
6268 | declare | |
6269 | DRC : constant Boolean := Do_Range_Check (Exp); | |
23abd64d | 6270 | PV : Node_Id; |
6271 | CE : Node_Id; | |
05fcfafb | 6272 | |
0577b0b1 | 6273 | begin |
6274 | Set_Do_Range_Check (Exp, False); | |
6275 | ||
06ad5813 | 6276 | -- Force evaluation to avoid multiple reads for atomic/volatile |
6277 | ||
6278 | if Is_Entity_Name (Exp) | |
6279 | and then Is_Volatile (Entity (Exp)) | |
6280 | then | |
6281 | Force_Evaluation (Exp, Name_Req => True); | |
6282 | end if; | |
6283 | ||
23abd64d | 6284 | -- Build the prefix for the 'Valid call |
6285 | ||
6286 | PV := Duplicate_Subexpr_No_Checks (Exp, Name_Req => True); | |
0577b0b1 | 6287 | |
23abd64d | 6288 | -- A rather specialized kludge. If PV is an analyzed expression |
6289 | -- which is an indexed component of a packed array that has not | |
6290 | -- been properly expanded, turn off its Analyzed flag to make sure | |
6291 | -- it gets properly reexpanded. | |
6292 | ||
6293 | -- The reason this arises is that Duplicate_Subexpr_No_Checks did | |
6294 | -- an analyze with the old parent pointer. This may point e.g. to | |
6295 | -- a subprogram call, which deactivates this expansion. | |
6296 | ||
6297 | if Analyzed (PV) | |
6298 | and then Nkind (PV) = N_Indexed_Component | |
6299 | and then Present (Packed_Array_Type (Etype (Prefix (PV)))) | |
6300 | then | |
6301 | Set_Analyzed (PV, False); | |
6302 | end if; | |
6303 | ||
6304 | -- Build the raise CE node to check for validity | |
6305 | ||
6306 | CE := | |
0577b0b1 | 6307 | Make_Raise_Constraint_Error (Loc, |
6308 | Condition => | |
6309 | Make_Op_Not (Loc, | |
6310 | Right_Opnd => | |
6311 | Make_Attribute_Reference (Loc, | |
23abd64d | 6312 | Prefix => PV, |
0577b0b1 | 6313 | Attribute_Name => Name_Valid)), |
23abd64d | 6314 | Reason => CE_Invalid_Data); |
6315 | ||
6316 | -- Insert the validity check. Note that we do this with validity | |
6317 | -- checks turned off, to avoid recursion, we do not want validity | |
6318 | -- checks on the validity checking code itself! | |
6319 | ||
6320 | Insert_Action (Expr, CE, Suppress => Validity_Check); | |
0577b0b1 | 6321 | |
6fb3c314 | 6322 | -- If the expression is a reference to an element of a bit-packed |
0577b0b1 | 6323 | -- array, then it is rewritten as a renaming declaration. If the |
6324 | -- expression is an actual in a call, it has not been expanded, | |
6325 | -- waiting for the proper point at which to do it. The same happens | |
6326 | -- with renamings, so that we have to force the expansion now. This | |
6327 | -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb | |
6328 | -- and exp_ch6.adb. | |
6329 | ||
6330 | if Is_Entity_Name (Exp) | |
6331 | and then Nkind (Parent (Entity (Exp))) = | |
6332 | N_Object_Renaming_Declaration | |
6333 | then | |
6334 | declare | |
6335 | Old_Exp : constant Node_Id := Name (Parent (Entity (Exp))); | |
6336 | begin | |
6337 | if Nkind (Old_Exp) = N_Indexed_Component | |
6338 | and then Is_Bit_Packed_Array (Etype (Prefix (Old_Exp))) | |
6339 | then | |
6340 | Expand_Packed_Element_Reference (Old_Exp); | |
6341 | end if; | |
6342 | end; | |
6343 | end if; | |
6344 | ||
6345 | -- Put back the Do_Range_Check flag on the resulting (possibly | |
6346 | -- rewritten) expression. | |
6347 | ||
6348 | -- Note: it might be thought that a validity check is not required | |
6349 | -- when a range check is present, but that's not the case, because | |
6350 | -- the back end is allowed to assume for the range check that the | |
6351 | -- operand is within its declared range (an assumption that validity | |
6352 | -- checking is all about NOT assuming!) | |
6353 | ||
00c403ee | 6354 | -- Note: no need to worry about Possible_Local_Raise here, it will |
6355 | -- already have been called if original node has Do_Range_Check set. | |
6356 | ||
0577b0b1 | 6357 | Set_Do_Range_Check (Exp, DRC); |
6358 | end; | |
ee6ba406 | 6359 | end Insert_Valid_Check; |
6360 | ||
3cce7f32 | 6361 | ------------------------------------- |
6362 | -- Is_Signed_Integer_Arithmetic_Op -- | |
6363 | ------------------------------------- | |
6364 | ||
6365 | function Is_Signed_Integer_Arithmetic_Op (N : Node_Id) return Boolean is | |
6366 | begin | |
6367 | case Nkind (N) is | |
6368 | when N_Op_Abs | N_Op_Add | N_Op_Divide | N_Op_Expon | | |
6369 | N_Op_Minus | N_Op_Mod | N_Op_Multiply | N_Op_Plus | | |
6370 | N_Op_Rem | N_Op_Subtract => | |
6371 | return Is_Signed_Integer_Type (Etype (N)); | |
6372 | ||
92f1631f | 6373 | when N_If_Expression | N_Case_Expression => |
0326b4d4 | 6374 | return Is_Signed_Integer_Type (Etype (N)); |
6375 | ||
3cce7f32 | 6376 | when others => |
6377 | return False; | |
6378 | end case; | |
6379 | end Is_Signed_Integer_Arithmetic_Op; | |
6380 | ||
fa7497e8 | 6381 | ---------------------------------- |
6382 | -- Install_Null_Excluding_Check -- | |
6383 | ---------------------------------- | |
6384 | ||
6385 | procedure Install_Null_Excluding_Check (N : Node_Id) is | |
9f294c82 | 6386 | Loc : constant Source_Ptr := Sloc (Parent (N)); |
84d0d4a5 | 6387 | Typ : constant Entity_Id := Etype (N); |
6388 | ||
7b31b357 | 6389 | function Safe_To_Capture_In_Parameter_Value return Boolean; |
6390 | -- Determines if it is safe to capture Known_Non_Null status for an | |
6391 | -- the entity referenced by node N. The caller ensures that N is indeed | |
6392 | -- an entity name. It is safe to capture the non-null status for an IN | |
6393 | -- parameter when the reference occurs within a declaration that is sure | |
6394 | -- to be executed as part of the declarative region. | |
7870823d | 6395 | |
84d0d4a5 | 6396 | procedure Mark_Non_Null; |
7870823d | 6397 | -- After installation of check, if the node in question is an entity |
6398 | -- name, then mark this entity as non-null if possible. | |
6399 | ||
7b31b357 | 6400 | function Safe_To_Capture_In_Parameter_Value return Boolean is |
7870823d | 6401 | E : constant Entity_Id := Entity (N); |
6402 | S : constant Entity_Id := Current_Scope; | |
6403 | S_Par : Node_Id; | |
6404 | ||
6405 | begin | |
7b31b357 | 6406 | if Ekind (E) /= E_In_Parameter then |
6407 | return False; | |
6408 | end if; | |
7870823d | 6409 | |
6410 | -- Two initial context checks. We must be inside a subprogram body | |
6411 | -- with declarations and reference must not appear in nested scopes. | |
6412 | ||
7b31b357 | 6413 | if (Ekind (S) /= E_Function and then Ekind (S) /= E_Procedure) |
7870823d | 6414 | or else Scope (E) /= S |
6415 | then | |
6416 | return False; | |
6417 | end if; | |
6418 | ||
6419 | S_Par := Parent (Parent (S)); | |
6420 | ||
6421 | if Nkind (S_Par) /= N_Subprogram_Body | |
6422 | or else No (Declarations (S_Par)) | |
6423 | then | |
6424 | return False; | |
6425 | end if; | |
6426 | ||
6427 | declare | |
6428 | N_Decl : Node_Id; | |
6429 | P : Node_Id; | |
6430 | ||
6431 | begin | |
6432 | -- Retrieve the declaration node of N (if any). Note that N | |
6433 | -- may be a part of a complex initialization expression. | |
6434 | ||
6435 | P := Parent (N); | |
6436 | N_Decl := Empty; | |
6437 | while Present (P) loop | |
6438 | ||
7b31b357 | 6439 | -- If we have a short circuit form, and we are within the right |
6440 | -- hand expression, we return false, since the right hand side | |
6441 | -- is not guaranteed to be elaborated. | |
6442 | ||
6443 | if Nkind (P) in N_Short_Circuit | |
6444 | and then N = Right_Opnd (P) | |
6445 | then | |
6446 | return False; | |
6447 | end if; | |
6448 | ||
92f1631f | 6449 | -- Similarly, if we are in an if expression and not part of the |
6450 | -- condition, then we return False, since neither the THEN or | |
6451 | -- ELSE dependent expressions will always be elaborated. | |
7b31b357 | 6452 | |
92f1631f | 6453 | if Nkind (P) = N_If_Expression |
7b31b357 | 6454 | and then N /= First (Expressions (P)) |
6455 | then | |
6456 | return False; | |
e977c0cf | 6457 | end if; |
6458 | ||
6fb3c314 | 6459 | -- If we are in a case expression, and not part of the |
e977c0cf | 6460 | -- expression, then we return False, since a particular |
92f1631f | 6461 | -- dependent expression may not always be elaborated |
e977c0cf | 6462 | |
6463 | if Nkind (P) = N_Case_Expression | |
6464 | and then N /= Expression (P) | |
6465 | then | |
6466 | return False; | |
7b31b357 | 6467 | end if; |
6468 | ||
7870823d | 6469 | -- While traversing the parent chain, we find that N |
6470 | -- belongs to a statement, thus it may never appear in | |
6471 | -- a declarative region. | |
6472 | ||
6473 | if Nkind (P) in N_Statement_Other_Than_Procedure_Call | |
6474 | or else Nkind (P) = N_Procedure_Call_Statement | |
6475 | then | |
6476 | return False; | |
6477 | end if; | |
6478 | ||
7b31b357 | 6479 | -- If we are at a declaration, record it and exit |
6480 | ||
7870823d | 6481 | if Nkind (P) in N_Declaration |
6482 | and then Nkind (P) not in N_Subprogram_Specification | |
6483 | then | |
6484 | N_Decl := P; | |
6485 | exit; | |
6486 | end if; | |
6487 | ||
6488 | P := Parent (P); | |
6489 | end loop; | |
6490 | ||
6491 | if No (N_Decl) then | |
6492 | return False; | |
6493 | end if; | |
6494 | ||
6495 | return List_Containing (N_Decl) = Declarations (S_Par); | |
6496 | end; | |
7b31b357 | 6497 | end Safe_To_Capture_In_Parameter_Value; |
84d0d4a5 | 6498 | |
6499 | ------------------- | |
6500 | -- Mark_Non_Null -- | |
6501 | ------------------- | |
6502 | ||
6503 | procedure Mark_Non_Null is | |
6504 | begin | |
7870823d | 6505 | -- Only case of interest is if node N is an entity name |
6506 | ||
84d0d4a5 | 6507 | if Is_Entity_Name (N) then |
7870823d | 6508 | |
6509 | -- For sure, we want to clear an indication that this is known to | |
6510 | -- be null, since if we get past this check, it definitely is not! | |
6511 | ||
84d0d4a5 | 6512 | Set_Is_Known_Null (Entity (N), False); |
6513 | ||
7870823d | 6514 | -- We can mark the entity as known to be non-null if either it is |
6515 | -- safe to capture the value, or in the case of an IN parameter, | |
6516 | -- which is a constant, if the check we just installed is in the | |
6517 | -- declarative region of the subprogram body. In this latter case, | |
7b31b357 | 6518 | -- a check is decisive for the rest of the body if the expression |
6519 | -- is sure to be elaborated, since we know we have to elaborate | |
6520 | -- all declarations before executing the body. | |
6521 | ||
6522 | -- Couldn't this always be part of Safe_To_Capture_Value ??? | |
7870823d | 6523 | |
6524 | if Safe_To_Capture_Value (N, Entity (N)) | |
7b31b357 | 6525 | or else Safe_To_Capture_In_Parameter_Value |
7870823d | 6526 | then |
6527 | Set_Is_Known_Non_Null (Entity (N)); | |
84d0d4a5 | 6528 | end if; |
6529 | end if; | |
6530 | end Mark_Non_Null; | |
6531 | ||
6532 | -- Start of processing for Install_Null_Excluding_Check | |
fa7497e8 | 6533 | |
6534 | begin | |
84d0d4a5 | 6535 | pragma Assert (Is_Access_Type (Typ)); |
fa7497e8 | 6536 | |
84d0d4a5 | 6537 | -- No check inside a generic (why not???) |
fa7497e8 | 6538 | |
84d0d4a5 | 6539 | if Inside_A_Generic then |
fa7497e8 | 6540 | return; |
84d0d4a5 | 6541 | end if; |
6542 | ||
6543 | -- No check needed if known to be non-null | |
6544 | ||
6545 | if Known_Non_Null (N) then | |
05fcfafb | 6546 | return; |
84d0d4a5 | 6547 | end if; |
fa7497e8 | 6548 | |
84d0d4a5 | 6549 | -- If known to be null, here is where we generate a compile time check |
6550 | ||
6551 | if Known_Null (N) then | |
d16989f1 | 6552 | |
6553 | -- Avoid generating warning message inside init procs | |
6554 | ||
6555 | if not Inside_Init_Proc then | |
6556 | Apply_Compile_Time_Constraint_Error | |
6557 | (N, | |
cb97ae5c | 6558 | "null value not allowed here??", |
d16989f1 | 6559 | CE_Access_Check_Failed); |
6560 | else | |
6561 | Insert_Action (N, | |
6562 | Make_Raise_Constraint_Error (Loc, | |
6563 | Reason => CE_Access_Check_Failed)); | |
6564 | end if; | |
6565 | ||
84d0d4a5 | 6566 | Mark_Non_Null; |
6567 | return; | |
6568 | end if; | |
6569 | ||
6570 | -- If entity is never assigned, for sure a warning is appropriate | |
6571 | ||
6572 | if Is_Entity_Name (N) then | |
6573 | Check_Unset_Reference (N); | |
fa7497e8 | 6574 | end if; |
84d0d4a5 | 6575 | |
6576 | -- No check needed if checks are suppressed on the range. Note that we | |
6577 | -- don't set Is_Known_Non_Null in this case (we could legitimately do | |
6578 | -- so, since the program is erroneous, but we don't like to casually | |
6579 | -- propagate such conclusions from erroneosity). | |
6580 | ||
6581 | if Access_Checks_Suppressed (Typ) then | |
6582 | return; | |
6583 | end if; | |
6584 | ||
2af58f67 | 6585 | -- No check needed for access to concurrent record types generated by |
6586 | -- the expander. This is not just an optimization (though it does indeed | |
6587 | -- remove junk checks). It also avoids generation of junk warnings. | |
6588 | ||
6589 | if Nkind (N) in N_Has_Chars | |
6590 | and then Chars (N) = Name_uObject | |
6591 | and then Is_Concurrent_Record_Type | |
6592 | (Directly_Designated_Type (Etype (N))) | |
6593 | then | |
6594 | return; | |
6595 | end if; | |
6596 | ||
228836e8 | 6597 | -- No check needed in interface thunks since the runtime check is |
6598 | -- already performed at the caller side. | |
6599 | ||
6600 | if Is_Thunk (Current_Scope) then | |
6601 | return; | |
6602 | end if; | |
6603 | ||
472ea160 | 6604 | -- No check needed for the Get_Current_Excep.all.all idiom generated by |
6605 | -- the expander within exception handlers, since we know that the value | |
6606 | -- can never be null. | |
6607 | ||
6608 | -- Is this really the right way to do this? Normally we generate such | |
6609 | -- code in the expander with checks off, and that's how we suppress this | |
6610 | -- kind of junk check ??? | |
6611 | ||
6612 | if Nkind (N) = N_Function_Call | |
6613 | and then Nkind (Name (N)) = N_Explicit_Dereference | |
6614 | and then Nkind (Prefix (Name (N))) = N_Identifier | |
6615 | and then Is_RTE (Entity (Prefix (Name (N))), RE_Get_Current_Excep) | |
6616 | then | |
6617 | return; | |
6618 | end if; | |
6619 | ||
84d0d4a5 | 6620 | -- Otherwise install access check |
6621 | ||
6622 | Insert_Action (N, | |
6623 | Make_Raise_Constraint_Error (Loc, | |
6624 | Condition => | |
6625 | Make_Op_Eq (Loc, | |
6626 | Left_Opnd => Duplicate_Subexpr_Move_Checks (N), | |
6627 | Right_Opnd => Make_Null (Loc)), | |
6628 | Reason => CE_Access_Check_Failed)); | |
6629 | ||
6630 | Mark_Non_Null; | |
fa7497e8 | 6631 | end Install_Null_Excluding_Check; |
6632 | ||
ee6ba406 | 6633 | -------------------------- |
6634 | -- Install_Static_Check -- | |
6635 | -------------------------- | |
6636 | ||
6637 | procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is | |
6638 | Stat : constant Boolean := Is_Static_Expression (R_Cno); | |
6639 | Typ : constant Entity_Id := Etype (R_Cno); | |
6640 | ||
6641 | begin | |
f15731c4 | 6642 | Rewrite (R_Cno, |
6643 | Make_Raise_Constraint_Error (Loc, | |
6644 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 6645 | Set_Analyzed (R_Cno); |
6646 | Set_Etype (R_Cno, Typ); | |
6647 | Set_Raises_Constraint_Error (R_Cno); | |
6648 | Set_Is_Static_Expression (R_Cno, Stat); | |
840ab274 | 6649 | |
6650 | -- Now deal with possible local raise handling | |
6651 | ||
6652 | Possible_Local_Raise (R_Cno, Standard_Constraint_Error); | |
ee6ba406 | 6653 | end Install_Static_Check; |
6654 | ||
3cce7f32 | 6655 | ------------------------- |
6656 | -- Is_Check_Suppressed -- | |
6657 | ------------------------- | |
6658 | ||
6659 | function Is_Check_Suppressed (E : Entity_Id; C : Check_Id) return Boolean is | |
6660 | Ptr : Suppress_Stack_Entry_Ptr; | |
6661 | ||
6662 | begin | |
6663 | -- First search the local entity suppress stack. We search this from the | |
6664 | -- top of the stack down so that we get the innermost entry that applies | |
6665 | -- to this case if there are nested entries. | |
6666 | ||
6667 | Ptr := Local_Suppress_Stack_Top; | |
6668 | while Ptr /= null loop | |
6669 | if (Ptr.Entity = Empty or else Ptr.Entity = E) | |
6670 | and then (Ptr.Check = All_Checks or else Ptr.Check = C) | |
6671 | then | |
6672 | return Ptr.Suppress; | |
6673 | end if; | |
6674 | ||
6675 | Ptr := Ptr.Prev; | |
6676 | end loop; | |
6677 | ||
6678 | -- Now search the global entity suppress table for a matching entry. | |
6679 | -- We also search this from the top down so that if there are multiple | |
6680 | -- pragmas for the same entity, the last one applies (not clear what | |
6681 | -- or whether the RM specifies this handling, but it seems reasonable). | |
6682 | ||
6683 | Ptr := Global_Suppress_Stack_Top; | |
6684 | while Ptr /= null loop | |
6685 | if (Ptr.Entity = Empty or else Ptr.Entity = E) | |
6686 | and then (Ptr.Check = All_Checks or else Ptr.Check = C) | |
6687 | then | |
6688 | return Ptr.Suppress; | |
6689 | end if; | |
6690 | ||
6691 | Ptr := Ptr.Prev; | |
6692 | end loop; | |
6693 | ||
6694 | -- If we did not find a matching entry, then use the normal scope | |
6695 | -- suppress value after all (actually this will be the global setting | |
6696 | -- since it clearly was not overridden at any point). For a predefined | |
6697 | -- check, we test the specific flag. For a user defined check, we check | |
6698 | -- the All_Checks flag. The Overflow flag requires special handling to | |
6699 | -- deal with the General vs Assertion case | |
6700 | ||
6701 | if C = Overflow_Check then | |
6702 | return Overflow_Checks_Suppressed (Empty); | |
6703 | elsif C in Predefined_Check_Id then | |
6704 | return Scope_Suppress.Suppress (C); | |
6705 | else | |
6706 | return Scope_Suppress.Suppress (All_Checks); | |
6707 | end if; | |
6708 | end Is_Check_Suppressed; | |
6709 | ||
9dfe12ae | 6710 | --------------------- |
6711 | -- Kill_All_Checks -- | |
6712 | --------------------- | |
6713 | ||
6714 | procedure Kill_All_Checks is | |
6715 | begin | |
6716 | if Debug_Flag_CC then | |
6717 | w ("Kill_All_Checks"); | |
6718 | end if; | |
6719 | ||
feff2f05 | 6720 | -- We reset the number of saved checks to zero, and also modify all |
6721 | -- stack entries for statement ranges to indicate that the number of | |
6722 | -- checks at each level is now zero. | |
9dfe12ae | 6723 | |
6724 | Num_Saved_Checks := 0; | |
6725 | ||
96da3284 | 6726 | -- Note: the Int'Min here avoids any possibility of J being out of |
6727 | -- range when called from e.g. Conditional_Statements_Begin. | |
6728 | ||
6729 | for J in 1 .. Int'Min (Saved_Checks_TOS, Saved_Checks_Stack'Last) loop | |
9dfe12ae | 6730 | Saved_Checks_Stack (J) := 0; |
6731 | end loop; | |
6732 | end Kill_All_Checks; | |
6733 | ||
6734 | ----------------- | |
6735 | -- Kill_Checks -- | |
6736 | ----------------- | |
6737 | ||
6738 | procedure Kill_Checks (V : Entity_Id) is | |
6739 | begin | |
6740 | if Debug_Flag_CC then | |
6741 | w ("Kill_Checks for entity", Int (V)); | |
6742 | end if; | |
6743 | ||
6744 | for J in 1 .. Num_Saved_Checks loop | |
6745 | if Saved_Checks (J).Entity = V then | |
6746 | if Debug_Flag_CC then | |
6747 | w (" Checks killed for saved check ", J); | |
6748 | end if; | |
6749 | ||
6750 | Saved_Checks (J).Killed := True; | |
6751 | end if; | |
6752 | end loop; | |
6753 | end Kill_Checks; | |
6754 | ||
ee6ba406 | 6755 | ------------------------------ |
6756 | -- Length_Checks_Suppressed -- | |
6757 | ------------------------------ | |
6758 | ||
6759 | function Length_Checks_Suppressed (E : Entity_Id) return Boolean is | |
6760 | begin | |
9dfe12ae | 6761 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
6762 | return Is_Check_Suppressed (E, Length_Check); | |
6763 | else | |
fafc6b97 | 6764 | return Scope_Suppress.Suppress (Length_Check); |
9dfe12ae | 6765 | end if; |
ee6ba406 | 6766 | end Length_Checks_Suppressed; |
6767 | ||
3cce7f32 | 6768 | ----------------------- |
6769 | -- Make_Bignum_Block -- | |
6770 | ----------------------- | |
6771 | ||
6772 | function Make_Bignum_Block (Loc : Source_Ptr) return Node_Id is | |
6773 | M : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uM); | |
ee6ba406 | 6774 | |
3cce7f32 | 6775 | begin |
6776 | return | |
6777 | Make_Block_Statement (Loc, | |
6778 | Declarations => New_List ( | |
6779 | Make_Object_Declaration (Loc, | |
6780 | Defining_Identifier => M, | |
6781 | Object_Definition => | |
6782 | New_Occurrence_Of (RTE (RE_Mark_Id), Loc), | |
6783 | Expression => | |
6784 | Make_Function_Call (Loc, | |
6785 | Name => New_Reference_To (RTE (RE_SS_Mark), Loc)))), | |
6786 | ||
6787 | Handled_Statement_Sequence => | |
6788 | Make_Handled_Sequence_Of_Statements (Loc, | |
6789 | Statements => New_List ( | |
6790 | Make_Procedure_Call_Statement (Loc, | |
6791 | Name => New_Occurrence_Of (RTE (RE_SS_Release), Loc), | |
6792 | Parameter_Associations => New_List ( | |
6793 | New_Reference_To (M, Loc)))))); | |
6794 | end Make_Bignum_Block; | |
6795 | ||
0df9d43f | 6796 | ---------------------------------- |
6797 | -- Minimize_Eliminate_Overflows -- | |
6798 | ---------------------------------- | |
3cce7f32 | 6799 | |
f32c377d | 6800 | -- This is a recursive routine that is called at the top of an expression |
6801 | -- tree to properly process overflow checking for a whole subtree by making | |
6802 | -- recursive calls to process operands. This processing may involve the use | |
6803 | -- of bignum or long long integer arithmetic, which will change the types | |
6804 | -- of operands and results. That's why we can't do this bottom up (since | |
21a55437 | 6805 | -- it would interfere with semantic analysis). |
f32c377d | 6806 | |
21a55437 | 6807 | -- What happens is that if MINIMIZED/ELIMINATED mode is in effect then |
0df9d43f | 6808 | -- the operator expansion routines, as well as the expansion routines for |
6809 | -- if/case expression, do nothing (for the moment) except call the routine | |
6810 | -- to apply the overflow check (Apply_Arithmetic_Overflow_Check). That | |
6811 | -- routine does nothing for non top-level nodes, so at the point where the | |
6812 | -- call is made for the top level node, the entire expression subtree has | |
6813 | -- not been expanded, or processed for overflow. All that has to happen as | |
6814 | -- a result of the top level call to this routine. | |
f32c377d | 6815 | |
6816 | -- As noted above, the overflow processing works by making recursive calls | |
6817 | -- for the operands, and figuring out what to do, based on the processing | |
6818 | -- of these operands (e.g. if a bignum operand appears, the parent op has | |
6819 | -- to be done in bignum mode), and the determined ranges of the operands. | |
6820 | ||
6821 | -- After possible rewriting of a constituent subexpression node, a call is | |
4fb5f0a0 | 6822 | -- made to either reexpand the node (if nothing has changed) or reanalyze |
21a55437 | 6823 | -- the node (if it has been modified by the overflow check processing). The |
6824 | -- Analyzed_Flag is set to False before the reexpand/reanalyze. To avoid | |
6825 | -- a recursive call into the whole overflow apparatus, an important rule | |
0df9d43f | 6826 | -- for this call is that the overflow handling mode must be temporarily set |
6827 | -- to STRICT. | |
f32c377d | 6828 | |
0df9d43f | 6829 | procedure Minimize_Eliminate_Overflows |
61016a7a | 6830 | (N : Node_Id; |
6831 | Lo : out Uint; | |
6832 | Hi : out Uint; | |
6833 | Top_Level : Boolean) | |
3cce7f32 | 6834 | is |
0326b4d4 | 6835 | Rtyp : constant Entity_Id := Etype (N); |
6836 | pragma Assert (Is_Signed_Integer_Type (Rtyp)); | |
6837 | -- Result type, must be a signed integer type | |
3cce7f32 | 6838 | |
db415383 | 6839 | Check_Mode : constant Overflow_Mode_Type := Overflow_Check_Mode; |
3cce7f32 | 6840 | pragma Assert (Check_Mode in Minimized_Or_Eliminated); |
6841 | ||
6842 | Loc : constant Source_Ptr := Sloc (N); | |
6843 | ||
6844 | Rlo, Rhi : Uint; | |
0326b4d4 | 6845 | -- Ranges of values for right operand (operator case) |
3cce7f32 | 6846 | |
6847 | Llo, Lhi : Uint; | |
0326b4d4 | 6848 | -- Ranges of values for left operand (operator case) |
3cce7f32 | 6849 | |
49b3a812 | 6850 | LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); |
6851 | -- Operands and results are of this type when we convert | |
6852 | ||
0326b4d4 | 6853 | LLLo : constant Uint := Intval (Type_Low_Bound (LLIB)); |
6854 | LLHi : constant Uint := Intval (Type_High_Bound (LLIB)); | |
3cce7f32 | 6855 | -- Bounds of Long_Long_Integer |
6856 | ||
6857 | Binary : constant Boolean := Nkind (N) in N_Binary_Op; | |
6858 | -- Indicates binary operator case | |
6859 | ||
6860 | OK : Boolean; | |
6861 | -- Used in call to Determine_Range | |
6862 | ||
61016a7a | 6863 | Bignum_Operands : Boolean; |
6864 | -- Set True if one or more operands is already of type Bignum, meaning | |
6865 | -- that for sure (regardless of Top_Level setting) we are committed to | |
0326b4d4 | 6866 | -- doing the operation in Bignum mode (or in the case of a case or if |
21a55437 | 6867 | -- expression, converting all the dependent expressions to Bignum). |
0326b4d4 | 6868 | |
6869 | Long_Long_Integer_Operands : Boolean; | |
21a55437 | 6870 | -- Set True if one or more operands is already of type Long_Long_Integer |
0326b4d4 | 6871 | -- which means that if the result is known to be in the result type |
6872 | -- range, then we must convert such operands back to the result type. | |
0df9d43f | 6873 | |
6874 | procedure Reanalyze (Typ : Entity_Id; Suppress : Boolean := False); | |
6875 | -- This is called when we have modified the node and we therefore need | |
6876 | -- to reanalyze it. It is important that we reset the mode to STRICT for | |
6877 | -- this reanalysis, since if we leave it in MINIMIZED or ELIMINATED mode | |
6878 | -- we would reenter this routine recursively which would not be good! | |
6879 | -- The argument Suppress is set True if we also want to suppress | |
6880 | -- overflow checking for the reexpansion (this is set when we know | |
6881 | -- overflow is not possible). Typ is the type for the reanalysis. | |
6882 | ||
6883 | procedure Reexpand (Suppress : Boolean := False); | |
6884 | -- This is like Reanalyze, but does not do the Analyze step, it only | |
6885 | -- does a reexpansion. We do this reexpansion in STRICT mode, so that | |
6886 | -- instead of reentering the MINIMIZED/ELIMINATED mode processing, we | |
6887 | -- follow the normal expansion path (e.g. converting A**4 to A**2**2). | |
6888 | -- Note that skipping reanalysis is not just an optimization, testing | |
6889 | -- has showed up several complex cases in which reanalyzing an already | |
6890 | -- analyzed node causes incorrect behavior. | |
4fb5f0a0 | 6891 | |
0326b4d4 | 6892 | function In_Result_Range return Boolean; |
6893 | -- Returns True iff Lo .. Hi are within range of the result type | |
61016a7a | 6894 | |
2fe22c69 | 6895 | procedure Max (A : in out Uint; B : Uint); |
21a55437 | 6896 | -- If A is No_Uint, sets A to B, else to UI_Max (A, B) |
2fe22c69 | 6897 | |
6898 | procedure Min (A : in out Uint; B : Uint); | |
21a55437 | 6899 | -- If A is No_Uint, sets A to B, else to UI_Min (A, B) |
2fe22c69 | 6900 | |
0326b4d4 | 6901 | --------------------- |
6902 | -- In_Result_Range -- | |
6903 | --------------------- | |
6904 | ||
6905 | function In_Result_Range return Boolean is | |
6906 | begin | |
f32c377d | 6907 | if Lo = No_Uint or else Hi = No_Uint then |
6908 | return False; | |
6909 | ||
6910 | elsif Is_Static_Subtype (Etype (N)) then | |
0326b4d4 | 6911 | return Lo >= Expr_Value (Type_Low_Bound (Rtyp)) |
6912 | and then | |
6913 | Hi <= Expr_Value (Type_High_Bound (Rtyp)); | |
f32c377d | 6914 | |
0326b4d4 | 6915 | else |
6916 | return Lo >= Expr_Value (Type_Low_Bound (Base_Type (Rtyp))) | |
6917 | and then | |
6918 | Hi <= Expr_Value (Type_High_Bound (Base_Type (Rtyp))); | |
6919 | end if; | |
6920 | end In_Result_Range; | |
6921 | ||
2fe22c69 | 6922 | --------- |
6923 | -- Max -- | |
6924 | --------- | |
6925 | ||
6926 | procedure Max (A : in out Uint; B : Uint) is | |
6927 | begin | |
6928 | if A = No_Uint or else B > A then | |
6929 | A := B; | |
6930 | end if; | |
6931 | end Max; | |
6932 | ||
6933 | --------- | |
6934 | -- Min -- | |
6935 | --------- | |
6936 | ||
6937 | procedure Min (A : in out Uint; B : Uint) is | |
6938 | begin | |
6939 | if A = No_Uint or else B < A then | |
6940 | A := B; | |
6941 | end if; | |
6942 | end Min; | |
6943 | ||
0df9d43f | 6944 | --------------- |
6945 | -- Reanalyze -- | |
6946 | --------------- | |
6947 | ||
6948 | procedure Reanalyze (Typ : Entity_Id; Suppress : Boolean := False) is | |
db415383 | 6949 | Svg : constant Overflow_Mode_Type := |
6950 | Scope_Suppress.Overflow_Mode_General; | |
6951 | Sva : constant Overflow_Mode_Type := | |
6952 | Scope_Suppress.Overflow_Mode_Assertions; | |
0df9d43f | 6953 | Svo : constant Boolean := |
6954 | Scope_Suppress.Suppress (Overflow_Check); | |
6955 | ||
6956 | begin | |
db415383 | 6957 | Scope_Suppress.Overflow_Mode_General := Strict; |
6958 | Scope_Suppress.Overflow_Mode_Assertions := Strict; | |
0df9d43f | 6959 | |
6960 | if Suppress then | |
6961 | Scope_Suppress.Suppress (Overflow_Check) := True; | |
6962 | end if; | |
6963 | ||
6964 | Analyze_And_Resolve (N, Typ); | |
6965 | ||
6966 | Scope_Suppress.Suppress (Overflow_Check) := Svo; | |
db415383 | 6967 | Scope_Suppress.Overflow_Mode_General := Svg; |
6968 | Scope_Suppress.Overflow_Mode_Assertions := Sva; | |
0df9d43f | 6969 | end Reanalyze; |
6970 | ||
4fb5f0a0 | 6971 | -------------- |
6972 | -- Reexpand -- | |
6973 | -------------- | |
6974 | ||
0df9d43f | 6975 | procedure Reexpand (Suppress : Boolean := False) is |
db415383 | 6976 | Svg : constant Overflow_Mode_Type := |
6977 | Scope_Suppress.Overflow_Mode_General; | |
6978 | Sva : constant Overflow_Mode_Type := | |
6979 | Scope_Suppress.Overflow_Mode_Assertions; | |
0df9d43f | 6980 | Svo : constant Boolean := |
6981 | Scope_Suppress.Suppress (Overflow_Check); | |
6982 | ||
4fb5f0a0 | 6983 | begin |
db415383 | 6984 | Scope_Suppress.Overflow_Mode_General := Strict; |
6985 | Scope_Suppress.Overflow_Mode_Assertions := Strict; | |
4fb5f0a0 | 6986 | Set_Analyzed (N, False); |
0df9d43f | 6987 | |
6988 | if Suppress then | |
6989 | Scope_Suppress.Suppress (Overflow_Check) := True; | |
6990 | end if; | |
6991 | ||
4fb5f0a0 | 6992 | Expand (N); |
0df9d43f | 6993 | |
6994 | Scope_Suppress.Suppress (Overflow_Check) := Svo; | |
db415383 | 6995 | Scope_Suppress.Overflow_Mode_General := Svg; |
6996 | Scope_Suppress.Overflow_Mode_Assertions := Sva; | |
4fb5f0a0 | 6997 | end Reexpand; |
6998 | ||
0df9d43f | 6999 | -- Start of processing for Minimize_Eliminate_Overflows |
2fe22c69 | 7000 | |
3cce7f32 | 7001 | begin |
0326b4d4 | 7002 | -- Case where we do not have a signed integer arithmetic operation |
3cce7f32 | 7003 | |
7004 | if not Is_Signed_Integer_Arithmetic_Op (N) then | |
7005 | ||
7006 | -- Use the normal Determine_Range routine to get the range. We | |
7007 | -- don't require operands to be valid, invalid values may result in | |
7008 | -- rubbish results where the result has not been properly checked for | |
7009 | -- overflow, that's fine! | |
7010 | ||
7011 | Determine_Range (N, OK, Lo, Hi, Assume_Valid => False); | |
7012 | ||
21a55437 | 7013 | -- If Determine_Range did not work (can this in fact happen? Not |
3cce7f32 | 7014 | -- clear but might as well protect), use type bounds. |
7015 | ||
7016 | if not OK then | |
7017 | Lo := Intval (Type_Low_Bound (Base_Type (Etype (N)))); | |
7018 | Hi := Intval (Type_High_Bound (Base_Type (Etype (N)))); | |
7019 | end if; | |
7020 | ||
7021 | -- If we don't have a binary operator, all we have to do is to set | |
7022 | -- the Hi/Lo range, so we are done | |
7023 | ||
7024 | return; | |
7025 | ||
0326b4d4 | 7026 | -- Processing for if expression |
7027 | ||
92f1631f | 7028 | elsif Nkind (N) = N_If_Expression then |
0326b4d4 | 7029 | declare |
7030 | Then_DE : constant Node_Id := Next (First (Expressions (N))); | |
7031 | Else_DE : constant Node_Id := Next (Then_DE); | |
7032 | ||
7033 | begin | |
7034 | Bignum_Operands := False; | |
7035 | ||
0df9d43f | 7036 | Minimize_Eliminate_Overflows |
0326b4d4 | 7037 | (Then_DE, Lo, Hi, Top_Level => False); |
7038 | ||
7039 | if Lo = No_Uint then | |
7040 | Bignum_Operands := True; | |
7041 | end if; | |
7042 | ||
0df9d43f | 7043 | Minimize_Eliminate_Overflows |
0326b4d4 | 7044 | (Else_DE, Rlo, Rhi, Top_Level => False); |
7045 | ||
7046 | if Rlo = No_Uint then | |
7047 | Bignum_Operands := True; | |
7048 | else | |
7049 | Long_Long_Integer_Operands := | |
7050 | Etype (Then_DE) = LLIB or else Etype (Else_DE) = LLIB; | |
7051 | ||
7052 | Min (Lo, Rlo); | |
7053 | Max (Hi, Rhi); | |
7054 | end if; | |
7055 | ||
21a55437 | 7056 | -- If at least one of our operands is now Bignum, we must rebuild |
7057 | -- the if expression to use Bignum operands. We will analyze the | |
0326b4d4 | 7058 | -- rebuilt if expression with overflow checks off, since once we |
7059 | -- are in bignum mode, we are all done with overflow checks! | |
7060 | ||
7061 | if Bignum_Operands then | |
7062 | Rewrite (N, | |
92f1631f | 7063 | Make_If_Expression (Loc, |
0326b4d4 | 7064 | Expressions => New_List ( |
7065 | Remove_Head (Expressions (N)), | |
7066 | Convert_To_Bignum (Then_DE), | |
7067 | Convert_To_Bignum (Else_DE)), | |
7068 | Is_Elsif => Is_Elsif (N))); | |
7069 | ||
0df9d43f | 7070 | Reanalyze (RTE (RE_Bignum), Suppress => True); |
0326b4d4 | 7071 | |
7072 | -- If we have no Long_Long_Integer operands, then we are in result | |
7073 | -- range, since it means that none of our operands felt the need | |
7074 | -- to worry about overflow (otherwise it would have already been | |
4fb5f0a0 | 7075 | -- converted to long long integer or bignum). We reexpand to |
7076 | -- complete the expansion of the if expression (but we do not | |
7077 | -- need to reanalyze). | |
0326b4d4 | 7078 | |
7079 | elsif not Long_Long_Integer_Operands then | |
7080 | Set_Do_Overflow_Check (N, False); | |
0df9d43f | 7081 | Reexpand; |
0326b4d4 | 7082 | |
7083 | -- Otherwise convert us to long long integer mode. Note that we | |
7084 | -- don't need any further overflow checking at this level. | |
7085 | ||
7086 | else | |
7087 | Convert_To_And_Rewrite (LLIB, Then_DE); | |
7088 | Convert_To_And_Rewrite (LLIB, Else_DE); | |
7089 | Set_Etype (N, LLIB); | |
f32c377d | 7090 | |
7091 | -- Now reanalyze with overflow checks off | |
7092 | ||
0326b4d4 | 7093 | Set_Do_Overflow_Check (N, False); |
0df9d43f | 7094 | Reanalyze (LLIB, Suppress => True); |
0326b4d4 | 7095 | end if; |
7096 | end; | |
7097 | ||
7098 | return; | |
7099 | ||
7100 | -- Here for case expression | |
7101 | ||
7102 | elsif Nkind (N) = N_Case_Expression then | |
7103 | Bignum_Operands := False; | |
7104 | Long_Long_Integer_Operands := False; | |
0326b4d4 | 7105 | |
7106 | declare | |
f32c377d | 7107 | Alt : Node_Id; |
0326b4d4 | 7108 | |
7109 | begin | |
7110 | -- Loop through expressions applying recursive call | |
7111 | ||
7112 | Alt := First (Alternatives (N)); | |
7113 | while Present (Alt) loop | |
7114 | declare | |
7115 | Aexp : constant Node_Id := Expression (Alt); | |
7116 | ||
7117 | begin | |
0df9d43f | 7118 | Minimize_Eliminate_Overflows |
0326b4d4 | 7119 | (Aexp, Lo, Hi, Top_Level => False); |
7120 | ||
7121 | if Lo = No_Uint then | |
7122 | Bignum_Operands := True; | |
7123 | elsif Etype (Aexp) = LLIB then | |
7124 | Long_Long_Integer_Operands := True; | |
7125 | end if; | |
7126 | end; | |
7127 | ||
7128 | Next (Alt); | |
7129 | end loop; | |
7130 | ||
7131 | -- If we have no bignum or long long integer operands, it means | |
7132 | -- that none of our dependent expressions could raise overflow. | |
7133 | -- In this case, we simply return with no changes except for | |
7134 | -- resetting the overflow flag, since we are done with overflow | |
4fb5f0a0 | 7135 | -- checks for this node. We will reexpand to get the needed |
7136 | -- expansion for the case expression, but we do not need to | |
21a55437 | 7137 | -- reanalyze, since nothing has changed. |
0326b4d4 | 7138 | |
f32c377d | 7139 | if not (Bignum_Operands or Long_Long_Integer_Operands) then |
0326b4d4 | 7140 | Set_Do_Overflow_Check (N, False); |
0df9d43f | 7141 | Reexpand (Suppress => True); |
0326b4d4 | 7142 | |
7143 | -- Otherwise we are going to rebuild the case expression using | |
7144 | -- either bignum or long long integer operands throughout. | |
7145 | ||
7146 | else | |
f32c377d | 7147 | declare |
7148 | Rtype : Entity_Id; | |
7149 | New_Alts : List_Id; | |
7150 | New_Exp : Node_Id; | |
7151 | ||
7152 | begin | |
7153 | New_Alts := New_List; | |
7154 | Alt := First (Alternatives (N)); | |
7155 | while Present (Alt) loop | |
7156 | if Bignum_Operands then | |
7157 | New_Exp := Convert_To_Bignum (Expression (Alt)); | |
7158 | Rtype := RTE (RE_Bignum); | |
7159 | else | |
7160 | New_Exp := Convert_To (LLIB, Expression (Alt)); | |
7161 | Rtype := LLIB; | |
7162 | end if; | |
0326b4d4 | 7163 | |
f32c377d | 7164 | Append_To (New_Alts, |
7165 | Make_Case_Expression_Alternative (Sloc (Alt), | |
7166 | Actions => No_List, | |
7167 | Discrete_Choices => Discrete_Choices (Alt), | |
7168 | Expression => New_Exp)); | |
0326b4d4 | 7169 | |
f32c377d | 7170 | Next (Alt); |
7171 | end loop; | |
0326b4d4 | 7172 | |
f32c377d | 7173 | Rewrite (N, |
7174 | Make_Case_Expression (Loc, | |
7175 | Expression => Expression (N), | |
7176 | Alternatives => New_Alts)); | |
0326b4d4 | 7177 | |
0df9d43f | 7178 | Reanalyze (Rtype, Suppress => True); |
f32c377d | 7179 | end; |
0326b4d4 | 7180 | end if; |
7181 | end; | |
7182 | ||
7183 | return; | |
7184 | end if; | |
7185 | ||
7186 | -- If we have an arithmetic operator we make recursive calls on the | |
3cce7f32 | 7187 | -- operands to get the ranges (and to properly process the subtree |
7188 | -- that lies below us!) | |
7189 | ||
0df9d43f | 7190 | Minimize_Eliminate_Overflows |
0326b4d4 | 7191 | (Right_Opnd (N), Rlo, Rhi, Top_Level => False); |
3cce7f32 | 7192 | |
0326b4d4 | 7193 | if Binary then |
0df9d43f | 7194 | Minimize_Eliminate_Overflows |
0326b4d4 | 7195 | (Left_Opnd (N), Llo, Lhi, Top_Level => False); |
3cce7f32 | 7196 | end if; |
7197 | ||
f32c377d | 7198 | -- Record if we have Long_Long_Integer operands |
7199 | ||
7200 | Long_Long_Integer_Operands := | |
7201 | Etype (Right_Opnd (N)) = LLIB | |
7202 | or else (Binary and then Etype (Left_Opnd (N)) = LLIB); | |
7203 | ||
7204 | -- If either operand is a bignum, then result will be a bignum and we | |
7205 | -- don't need to do any range analysis. As previously discussed we could | |
7206 | -- do range analysis in such cases, but it could mean working with giant | |
7207 | -- numbers at compile time for very little gain (the number of cases | |
21a55437 | 7208 | -- in which we could slip back from bignum mode is small). |
3cce7f32 | 7209 | |
7210 | if Rlo = No_Uint or else (Binary and then Llo = No_Uint) then | |
7211 | Lo := No_Uint; | |
7212 | Hi := No_Uint; | |
61016a7a | 7213 | Bignum_Operands := True; |
3cce7f32 | 7214 | |
7215 | -- Otherwise compute result range | |
7216 | ||
7217 | else | |
61016a7a | 7218 | Bignum_Operands := False; |
7219 | ||
3cce7f32 | 7220 | case Nkind (N) is |
7221 | ||
7222 | -- Absolute value | |
7223 | ||
7224 | when N_Op_Abs => | |
7225 | Lo := Uint_0; | |
de922300 | 7226 | Hi := UI_Max (abs Rlo, abs Rhi); |
3cce7f32 | 7227 | |
7228 | -- Addition | |
7229 | ||
7230 | when N_Op_Add => | |
7231 | Lo := Llo + Rlo; | |
7232 | Hi := Lhi + Rhi; | |
7233 | ||
7234 | -- Division | |
7235 | ||
7236 | when N_Op_Divide => | |
2fe22c69 | 7237 | |
5f4275e1 | 7238 | -- If the right operand can only be zero, set 0..0 |
2fe22c69 | 7239 | |
5f4275e1 | 7240 | if Rlo = 0 and then Rhi = 0 then |
7241 | Lo := Uint_0; | |
7242 | Hi := Uint_0; | |
2fe22c69 | 7243 | |
5f4275e1 | 7244 | -- Possible bounds of division must come from dividing end |
7245 | -- values of the input ranges (four possibilities), provided | |
7246 | -- zero is not included in the possible values of the right | |
7247 | -- operand. | |
7248 | ||
7249 | -- Otherwise, we just consider two intervals of values for | |
7250 | -- the right operand: the interval of negative values (up to | |
7251 | -- -1) and the interval of positive values (starting at 1). | |
7252 | -- Since division by 1 is the identity, and division by -1 | |
7253 | -- is negation, we get all possible bounds of division in that | |
7254 | -- case by considering: | |
7255 | -- - all values from the division of end values of input | |
7256 | -- ranges; | |
7257 | -- - the end values of the left operand; | |
7258 | -- - the negation of the end values of the left operand. | |
2fe22c69 | 7259 | |
5f4275e1 | 7260 | else |
7261 | declare | |
7262 | Mrk : constant Uintp.Save_Mark := Mark; | |
7263 | -- Mark so we can release the RR and Ev values | |
2fe22c69 | 7264 | |
5f4275e1 | 7265 | Ev1 : Uint; |
7266 | Ev2 : Uint; | |
7267 | Ev3 : Uint; | |
7268 | Ev4 : Uint; | |
2fe22c69 | 7269 | |
5f4275e1 | 7270 | begin |
7271 | -- Discard extreme values of zero for the divisor, since | |
7272 | -- they will simply result in an exception in any case. | |
2fe22c69 | 7273 | |
5f4275e1 | 7274 | if Rlo = 0 then |
7275 | Rlo := Uint_1; | |
7276 | elsif Rhi = 0 then | |
7277 | Rhi := -Uint_1; | |
2fe22c69 | 7278 | end if; |
2fe22c69 | 7279 | |
5f4275e1 | 7280 | -- Compute possible bounds coming from dividing end |
7281 | -- values of the input ranges. | |
2fe22c69 | 7282 | |
5f4275e1 | 7283 | Ev1 := Llo / Rlo; |
7284 | Ev2 := Llo / Rhi; | |
7285 | Ev3 := Lhi / Rlo; | |
7286 | Ev4 := Lhi / Rhi; | |
2fe22c69 | 7287 | |
5f4275e1 | 7288 | Lo := UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4)); |
7289 | Hi := UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4)); | |
2fe22c69 | 7290 | |
5f4275e1 | 7291 | -- If the right operand can be both negative or positive, |
7292 | -- include the end values of the left operand in the | |
7293 | -- extreme values, as well as their negation. | |
2fe22c69 | 7294 | |
5f4275e1 | 7295 | if Rlo < 0 and then Rhi > 0 then |
7296 | Ev1 := Llo; | |
7297 | Ev2 := -Llo; | |
7298 | Ev3 := Lhi; | |
7299 | Ev4 := -Lhi; | |
2fe22c69 | 7300 | |
5f4275e1 | 7301 | Min (Lo, |
7302 | UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4))); | |
7303 | Max (Hi, | |
7304 | UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4))); | |
2fe22c69 | 7305 | end if; |
2fe22c69 | 7306 | |
5f4275e1 | 7307 | -- Release the RR and Ev values |
2fe22c69 | 7308 | |
5f4275e1 | 7309 | Release_And_Save (Mrk, Lo, Hi); |
7310 | end; | |
7311 | end if; | |
3cce7f32 | 7312 | |
7313 | -- Exponentiation | |
7314 | ||
7315 | when N_Op_Expon => | |
de922300 | 7316 | |
7317 | -- Discard negative values for the exponent, since they will | |
7318 | -- simply result in an exception in any case. | |
7319 | ||
7320 | if Rhi < 0 then | |
7321 | Rhi := Uint_0; | |
7322 | elsif Rlo < 0 then | |
7323 | Rlo := Uint_0; | |
7324 | end if; | |
7325 | ||
7326 | -- Estimate number of bits in result before we go computing | |
7327 | -- giant useless bounds. Basically the number of bits in the | |
7328 | -- result is the number of bits in the base multiplied by the | |
7329 | -- value of the exponent. If this is big enough that the result | |
7330 | -- definitely won't fit in Long_Long_Integer, switch to bignum | |
7331 | -- mode immediately, and avoid computing giant bounds. | |
7332 | ||
7333 | -- The comparison here is approximate, but conservative, it | |
7334 | -- only clicks on cases that are sure to exceed the bounds. | |
7335 | ||
7336 | if Num_Bits (UI_Max (abs Llo, abs Lhi)) * Rhi + 1 > 100 then | |
7337 | Lo := No_Uint; | |
7338 | Hi := No_Uint; | |
7339 | ||
7340 | -- If right operand is zero then result is 1 | |
7341 | ||
7342 | elsif Rhi = 0 then | |
7343 | Lo := Uint_1; | |
7344 | Hi := Uint_1; | |
7345 | ||
7346 | else | |
7347 | -- High bound comes either from exponentiation of largest | |
5f4275e1 | 7348 | -- positive value to largest exponent value, or from |
7349 | -- the exponentiation of most negative value to an | |
7350 | -- even exponent. | |
de922300 | 7351 | |
7352 | declare | |
7353 | Hi1, Hi2 : Uint; | |
7354 | ||
7355 | begin | |
5f4275e1 | 7356 | if Lhi > 0 then |
de922300 | 7357 | Hi1 := Lhi ** Rhi; |
7358 | else | |
7359 | Hi1 := Uint_0; | |
7360 | end if; | |
7361 | ||
7362 | if Llo < 0 then | |
7363 | if Rhi mod 2 = 0 then | |
de922300 | 7364 | Hi2 := Llo ** Rhi; |
5f4275e1 | 7365 | else |
7366 | Hi2 := Llo ** (Rhi - 1); | |
de922300 | 7367 | end if; |
7368 | else | |
7369 | Hi2 := Uint_0; | |
7370 | end if; | |
7371 | ||
7372 | Hi := UI_Max (Hi1, Hi2); | |
7373 | end; | |
7374 | ||
7375 | -- Result can only be negative if base can be negative | |
7376 | ||
7377 | if Llo < 0 then | |
21a55437 | 7378 | if Rhi mod 2 = 0 then |
de922300 | 7379 | Lo := Llo ** (Rhi - 1); |
7380 | else | |
7381 | Lo := Llo ** Rhi; | |
7382 | end if; | |
7383 | ||
21a55437 | 7384 | -- Otherwise low bound is minimum ** minimum |
de922300 | 7385 | |
7386 | else | |
7387 | Lo := Llo ** Rlo; | |
7388 | end if; | |
7389 | end if; | |
3cce7f32 | 7390 | |
7391 | -- Negation | |
7392 | ||
7393 | when N_Op_Minus => | |
7394 | Lo := -Rhi; | |
7395 | Hi := -Rlo; | |
7396 | ||
7397 | -- Mod | |
7398 | ||
7399 | when N_Op_Mod => | |
2fe22c69 | 7400 | declare |
5f4275e1 | 7401 | Maxabs : constant Uint := UI_Max (abs Rlo, abs Rhi) - 1; |
2fe22c69 | 7402 | -- This is the maximum absolute value of the result |
7403 | ||
7404 | begin | |
7405 | Lo := Uint_0; | |
7406 | Hi := Uint_0; | |
7407 | ||
7408 | -- The result depends only on the sign and magnitude of | |
7409 | -- the right operand, it does not depend on the sign or | |
7410 | -- magnitude of the left operand. | |
7411 | ||
7412 | if Rlo < 0 then | |
7413 | Lo := -Maxabs; | |
7414 | end if; | |
7415 | ||
7416 | if Rhi > 0 then | |
7417 | Hi := Maxabs; | |
7418 | end if; | |
7419 | end; | |
3cce7f32 | 7420 | |
7421 | -- Multiplication | |
7422 | ||
7423 | when N_Op_Multiply => | |
49b3a812 | 7424 | |
7425 | -- Possible bounds of multiplication must come from multiplying | |
7426 | -- end values of the input ranges (four possibilities). | |
7427 | ||
7428 | declare | |
7429 | Mrk : constant Uintp.Save_Mark := Mark; | |
7430 | -- Mark so we can release the Ev values | |
7431 | ||
7432 | Ev1 : constant Uint := Llo * Rlo; | |
7433 | Ev2 : constant Uint := Llo * Rhi; | |
7434 | Ev3 : constant Uint := Lhi * Rlo; | |
7435 | Ev4 : constant Uint := Lhi * Rhi; | |
7436 | ||
7437 | begin | |
7438 | Lo := UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4)); | |
7439 | Hi := UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4)); | |
7440 | ||
7441 | -- Release the Ev values | |
7442 | ||
7443 | Release_And_Save (Mrk, Lo, Hi); | |
7444 | end; | |
3cce7f32 | 7445 | |
7446 | -- Plus operator (affirmation) | |
7447 | ||
7448 | when N_Op_Plus => | |
7449 | Lo := Rlo; | |
7450 | Hi := Rhi; | |
7451 | ||
7452 | -- Remainder | |
7453 | ||
7454 | when N_Op_Rem => | |
2fe22c69 | 7455 | declare |
5f4275e1 | 7456 | Maxabs : constant Uint := UI_Max (abs Rlo, abs Rhi) - 1; |
2fe22c69 | 7457 | -- This is the maximum absolute value of the result. Note |
5f4275e1 | 7458 | -- that the result range does not depend on the sign of the |
7459 | -- right operand. | |
2fe22c69 | 7460 | |
7461 | begin | |
7462 | Lo := Uint_0; | |
7463 | Hi := Uint_0; | |
7464 | ||
7465 | -- Case of left operand negative, which results in a range | |
7466 | -- of -Maxabs .. 0 for those negative values. If there are | |
7467 | -- no negative values then Lo value of result is always 0. | |
7468 | ||
7469 | if Llo < 0 then | |
7470 | Lo := -Maxabs; | |
7471 | end if; | |
7472 | ||
7473 | -- Case of left operand positive | |
7474 | ||
7475 | if Lhi > 0 then | |
7476 | Hi := Maxabs; | |
7477 | end if; | |
7478 | end; | |
3cce7f32 | 7479 | |
7480 | -- Subtract | |
7481 | ||
7482 | when N_Op_Subtract => | |
7483 | Lo := Llo - Rhi; | |
7484 | Hi := Lhi - Rlo; | |
7485 | ||
7486 | -- Nothing else should be possible | |
7487 | ||
7488 | when others => | |
7489 | raise Program_Error; | |
3cce7f32 | 7490 | end case; |
7491 | end if; | |
7492 | ||
4fb5f0a0 | 7493 | -- Here for the case where we have not rewritten anything (no bignum |
21a55437 | 7494 | -- operands or long long integer operands), and we know the result. |
7495 | -- If we know we are in the result range, and we do not have Bignum | |
7496 | -- operands or Long_Long_Integer operands, we can just reexpand with | |
7497 | -- overflow checks turned off (since we know we cannot have overflow). | |
7498 | -- As always the reexpansion is required to complete expansion of the | |
7499 | -- operator, but we do not need to reanalyze, and we prevent recursion | |
7500 | -- by suppressing the check. | |
f32c377d | 7501 | |
7502 | if not (Bignum_Operands or Long_Long_Integer_Operands) | |
7503 | and then In_Result_Range | |
7504 | then | |
7505 | Set_Do_Overflow_Check (N, False); | |
0df9d43f | 7506 | Reexpand (Suppress => True); |
f32c377d | 7507 | return; |
7508 | ||
7509 | -- Here we know that we are not in the result range, and in the general | |
21a55437 | 7510 | -- case we will move into either the Bignum or Long_Long_Integer domain |
7511 | -- to compute the result. However, there is one exception. If we are | |
7512 | -- at the top level, and we do not have Bignum or Long_Long_Integer | |
7513 | -- operands, we will have to immediately convert the result back to | |
7514 | -- the result type, so there is no point in Bignum/Long_Long_Integer | |
7515 | -- fiddling. | |
f32c377d | 7516 | |
7517 | elsif Top_Level | |
7518 | and then not (Bignum_Operands or Long_Long_Integer_Operands) | |
b6a8f264 | 7519 | |
7520 | -- One further refinement. If we are at the top level, but our parent | |
7521 | -- is a type conversion, then go into bignum or long long integer node | |
7522 | -- since the result will be converted to that type directly without | |
7523 | -- going through the result type, and we may avoid an overflow. This | |
7524 | -- is the case for example of Long_Long_Integer (A ** 4), where A is | |
7525 | -- of type Integer, and the result A ** 4 fits in Long_Long_Integer | |
7526 | -- but does not fit in Integer. | |
7527 | ||
7528 | and then Nkind (Parent (N)) /= N_Type_Conversion | |
f32c377d | 7529 | then |
0df9d43f | 7530 | -- Here keep original types, but we need to complete analysis |
f32c377d | 7531 | |
7532 | -- One subtlety. We can't just go ahead and do an analyze operation | |
21a55437 | 7533 | -- here because it will cause recursion into the whole MINIMIZED/ |
7534 | -- ELIMINATED overflow processing which is not what we want. Here | |
f32c377d | 7535 | -- we are at the top level, and we need a check against the result |
0df9d43f | 7536 | -- mode (i.e. we want to use STRICT mode). So do exactly that! |
4fb5f0a0 | 7537 | -- Also, we have not modified the node, so this is a case where |
7538 | -- we need to reexpand, but not reanalyze. | |
f32c377d | 7539 | |
0df9d43f | 7540 | Reexpand; |
f32c377d | 7541 | return; |
7542 | ||
7543 | -- Cases where we do the operation in Bignum mode. This happens either | |
3cce7f32 | 7544 | -- because one of our operands is in Bignum mode already, or because |
de922300 | 7545 | -- the computed bounds are outside the bounds of Long_Long_Integer, |
7546 | -- which in some cases can be indicated by Hi and Lo being No_Uint. | |
3cce7f32 | 7547 | |
7548 | -- Note: we could do better here and in some cases switch back from | |
7549 | -- Bignum mode to normal mode, e.g. big mod 2 must be in the range | |
7550 | -- 0 .. 1, but the cases are rare and it is not worth the effort. | |
7551 | -- Failing to do this switching back is only an efficiency issue. | |
7552 | ||
f32c377d | 7553 | elsif Lo = No_Uint or else Lo < LLLo or else Hi > LLHi then |
3cce7f32 | 7554 | |
61016a7a | 7555 | -- OK, we are definitely outside the range of Long_Long_Integer. The |
f32c377d | 7556 | -- question is whether to move to Bignum mode, or stay in the domain |
61016a7a | 7557 | -- of Long_Long_Integer, signalling that an overflow check is needed. |
7558 | ||
7559 | -- Obviously in MINIMIZED mode we stay with LLI, since we are not in | |
7560 | -- the Bignum business. In ELIMINATED mode, we will normally move | |
7561 | -- into Bignum mode, but there is an exception if neither of our | |
7562 | -- operands is Bignum now, and we are at the top level (Top_Level | |
7563 | -- set True). In this case, there is no point in moving into Bignum | |
7564 | -- mode to prevent overflow if the caller will immediately convert | |
7565 | -- the Bignum value back to LLI with an overflow check. It's more | |
0df9d43f | 7566 | -- efficient to stay in LLI mode with an overflow check (if needed) |
61016a7a | 7567 | |
7568 | if Check_Mode = Minimized | |
7569 | or else (Top_Level and not Bignum_Operands) | |
7570 | then | |
0df9d43f | 7571 | if Do_Overflow_Check (N) then |
7572 | Enable_Overflow_Check (N); | |
7573 | end if; | |
3cce7f32 | 7574 | |
0df9d43f | 7575 | -- The result now has to be in Long_Long_Integer mode, so adjust |
7576 | -- the possible range to reflect this. Note these calls also | |
7577 | -- change No_Uint values from the top level case to LLI bounds. | |
61016a7a | 7578 | |
7579 | Max (Lo, LLLo); | |
7580 | Min (Hi, LLHi); | |
7581 | ||
7582 | -- Otherwise we are in ELIMINATED mode and we switch to Bignum mode | |
3cce7f32 | 7583 | |
7584 | else | |
7585 | pragma Assert (Check_Mode = Eliminated); | |
7586 | ||
7587 | declare | |
7588 | Fent : Entity_Id; | |
7589 | Args : List_Id; | |
7590 | ||
7591 | begin | |
7592 | case Nkind (N) is | |
7593 | when N_Op_Abs => | |
7594 | Fent := RTE (RE_Big_Abs); | |
7595 | ||
7596 | when N_Op_Add => | |
7597 | Fent := RTE (RE_Big_Add); | |
7598 | ||
7599 | when N_Op_Divide => | |
7600 | Fent := RTE (RE_Big_Div); | |
7601 | ||
7602 | when N_Op_Expon => | |
7603 | Fent := RTE (RE_Big_Exp); | |
7604 | ||
7605 | when N_Op_Minus => | |
7606 | Fent := RTE (RE_Big_Neg); | |
7607 | ||
7608 | when N_Op_Mod => | |
7609 | Fent := RTE (RE_Big_Mod); | |
7610 | ||
7611 | when N_Op_Multiply => | |
7612 | Fent := RTE (RE_Big_Mul); | |
7613 | ||
7614 | when N_Op_Rem => | |
7615 | Fent := RTE (RE_Big_Rem); | |
7616 | ||
7617 | when N_Op_Subtract => | |
7618 | Fent := RTE (RE_Big_Sub); | |
7619 | ||
7620 | -- Anything else is an internal error, this includes the | |
7621 | -- N_Op_Plus case, since how can plus cause the result | |
7622 | -- to be out of range if the operand is in range? | |
7623 | ||
7624 | when others => | |
7625 | raise Program_Error; | |
7626 | end case; | |
7627 | ||
7628 | -- Construct argument list for Bignum call, converting our | |
7629 | -- operands to Bignum form if they are not already there. | |
7630 | ||
7631 | Args := New_List; | |
7632 | ||
7633 | if Binary then | |
7634 | Append_To (Args, Convert_To_Bignum (Left_Opnd (N))); | |
7635 | end if; | |
7636 | ||
7637 | Append_To (Args, Convert_To_Bignum (Right_Opnd (N))); | |
7638 | ||
7639 | -- Now rewrite the arithmetic operator with a call to the | |
7640 | -- corresponding bignum function. | |
7641 | ||
7642 | Rewrite (N, | |
7643 | Make_Function_Call (Loc, | |
7644 | Name => New_Occurrence_Of (Fent, Loc), | |
7645 | Parameter_Associations => Args)); | |
0df9d43f | 7646 | Reanalyze (RTE (RE_Bignum), Suppress => True); |
61016a7a | 7647 | |
7648 | -- Indicate result is Bignum mode | |
7649 | ||
7650 | Lo := No_Uint; | |
7651 | Hi := No_Uint; | |
de922300 | 7652 | return; |
3cce7f32 | 7653 | end; |
7654 | end if; | |
7655 | ||
7656 | -- Otherwise we are in range of Long_Long_Integer, so no overflow | |
de922300 | 7657 | -- check is required, at least not yet. |
3cce7f32 | 7658 | |
7659 | else | |
de922300 | 7660 | Set_Do_Overflow_Check (N, False); |
7661 | end if; | |
3cce7f32 | 7662 | |
f32c377d | 7663 | -- Here we are not in Bignum territory, but we may have long long |
7664 | -- integer operands that need special handling. First a special check: | |
7665 | -- If an exponentiation operator exponent is of type Long_Long_Integer, | |
7666 | -- it means we converted it to prevent overflow, but exponentiation | |
7667 | -- requires a Natural right operand, so convert it back to Natural. | |
7668 | -- This conversion may raise an exception which is fine. | |
0326b4d4 | 7669 | |
f32c377d | 7670 | if Nkind (N) = N_Op_Expon and then Etype (Right_Opnd (N)) = LLIB then |
7671 | Convert_To_And_Rewrite (Standard_Natural, Right_Opnd (N)); | |
0326b4d4 | 7672 | end if; |
7673 | ||
de922300 | 7674 | -- Here we will do the operation in Long_Long_Integer. We do this even |
7675 | -- if we know an overflow check is required, better to do this in long | |
7676 | -- long integer mode, since we are less likely to overflow! | |
3cce7f32 | 7677 | |
de922300 | 7678 | -- Convert right or only operand to Long_Long_Integer, except that |
7679 | -- we do not touch the exponentiation right operand. | |
3cce7f32 | 7680 | |
de922300 | 7681 | if Nkind (N) /= N_Op_Expon then |
7682 | Convert_To_And_Rewrite (LLIB, Right_Opnd (N)); | |
7683 | end if; | |
3cce7f32 | 7684 | |
de922300 | 7685 | -- Convert left operand to Long_Long_Integer for binary case |
49b3a812 | 7686 | |
de922300 | 7687 | if Binary then |
7688 | Convert_To_And_Rewrite (LLIB, Left_Opnd (N)); | |
7689 | end if; | |
7690 | ||
7691 | -- Reset node to unanalyzed | |
7692 | ||
7693 | Set_Analyzed (N, False); | |
7694 | Set_Etype (N, Empty); | |
7695 | Set_Entity (N, Empty); | |
7696 | ||
2fe22c69 | 7697 | -- Now analyze this new node. This reanalysis will complete processing |
7698 | -- for the node. In particular we will complete the expansion of an | |
7699 | -- exponentiation operator (e.g. changing A ** 2 to A * A), and also | |
7700 | -- we will complete any division checks (since we have not changed the | |
7701 | -- setting of the Do_Division_Check flag). | |
3cce7f32 | 7702 | |
0df9d43f | 7703 | -- We do this reanalysis in STRICT mode to avoid recursion into the |
7704 | -- MINIMIZED/ELIMINATED handling, since we are now done with that! | |
3cce7f32 | 7705 | |
0df9d43f | 7706 | declare |
db415383 | 7707 | SG : constant Overflow_Mode_Type := |
7708 | Scope_Suppress.Overflow_Mode_General; | |
7709 | SA : constant Overflow_Mode_Type := | |
7710 | Scope_Suppress.Overflow_Mode_Assertions; | |
de922300 | 7711 | |
0df9d43f | 7712 | begin |
db415383 | 7713 | Scope_Suppress.Overflow_Mode_General := Strict; |
7714 | Scope_Suppress.Overflow_Mode_Assertions := Strict; | |
de922300 | 7715 | |
0df9d43f | 7716 | if not Do_Overflow_Check (N) then |
7717 | Reanalyze (LLIB, Suppress => True); | |
7718 | else | |
7719 | Reanalyze (LLIB); | |
7720 | end if; | |
7721 | ||
db415383 | 7722 | Scope_Suppress.Overflow_Mode_General := SG; |
7723 | Scope_Suppress.Overflow_Mode_Assertions := SA; | |
0df9d43f | 7724 | end; |
7725 | end Minimize_Eliminate_Overflows; | |
3cce7f32 | 7726 | |
7727 | ------------------------- | |
7728 | -- Overflow_Check_Mode -- | |
7729 | ------------------------- | |
7730 | ||
db415383 | 7731 | function Overflow_Check_Mode return Overflow_Mode_Type is |
ee6ba406 | 7732 | begin |
724d2bd8 | 7733 | if In_Assertion_Expr = 0 then |
db415383 | 7734 | return Scope_Suppress.Overflow_Mode_General; |
9dfe12ae | 7735 | else |
db415383 | 7736 | return Scope_Suppress.Overflow_Mode_Assertions; |
9dfe12ae | 7737 | end if; |
3cce7f32 | 7738 | end Overflow_Check_Mode; |
7739 | ||
7740 | -------------------------------- | |
7741 | -- Overflow_Checks_Suppressed -- | |
7742 | -------------------------------- | |
7743 | ||
7744 | function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is | |
7745 | begin | |
0df9d43f | 7746 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
7747 | return Is_Check_Suppressed (E, Overflow_Check); | |
7748 | else | |
7749 | return Scope_Suppress.Suppress (Overflow_Check); | |
7750 | end if; | |
ee6ba406 | 7751 | end Overflow_Checks_Suppressed; |
fc75802a | 7752 | |
ee6ba406 | 7753 | ----------------------------- |
7754 | -- Range_Checks_Suppressed -- | |
7755 | ----------------------------- | |
7756 | ||
7757 | function Range_Checks_Suppressed (E : Entity_Id) return Boolean is | |
7758 | begin | |
9dfe12ae | 7759 | if Present (E) then |
7760 | ||
7761 | -- Note: for now we always suppress range checks on Vax float types, | |
7762 | -- since Gigi does not know how to generate these checks. | |
7763 | ||
7764 | if Vax_Float (E) then | |
7765 | return True; | |
7766 | elsif Kill_Range_Checks (E) then | |
7767 | return True; | |
7768 | elsif Checks_May_Be_Suppressed (E) then | |
7769 | return Is_Check_Suppressed (E, Range_Check); | |
7770 | end if; | |
7771 | end if; | |
ee6ba406 | 7772 | |
fafc6b97 | 7773 | return Scope_Suppress.Suppress (Range_Check); |
ee6ba406 | 7774 | end Range_Checks_Suppressed; |
7775 | ||
0577b0b1 | 7776 | ----------------------------------------- |
7777 | -- Range_Or_Validity_Checks_Suppressed -- | |
7778 | ----------------------------------------- | |
7779 | ||
7780 | -- Note: the coding would be simpler here if we simply made appropriate | |
7781 | -- calls to Range/Validity_Checks_Suppressed, but that would result in | |
7782 | -- duplicated checks which we prefer to avoid. | |
7783 | ||
7784 | function Range_Or_Validity_Checks_Suppressed | |
7785 | (Expr : Node_Id) return Boolean | |
7786 | is | |
7787 | begin | |
7788 | -- Immediate return if scope checks suppressed for either check | |
7789 | ||
fafc6b97 | 7790 | if Scope_Suppress.Suppress (Range_Check) |
7791 | or | |
7792 | Scope_Suppress.Suppress (Validity_Check) | |
7793 | then | |
0577b0b1 | 7794 | return True; |
7795 | end if; | |
7796 | ||
7797 | -- If no expression, that's odd, decide that checks are suppressed, | |
7798 | -- since we don't want anyone trying to do checks in this case, which | |
7799 | -- is most likely the result of some other error. | |
7800 | ||
7801 | if No (Expr) then | |
7802 | return True; | |
7803 | end if; | |
7804 | ||
7805 | -- Expression is present, so perform suppress checks on type | |
7806 | ||
7807 | declare | |
7808 | Typ : constant Entity_Id := Etype (Expr); | |
7809 | begin | |
7810 | if Vax_Float (Typ) then | |
7811 | return True; | |
7812 | elsif Checks_May_Be_Suppressed (Typ) | |
7813 | and then (Is_Check_Suppressed (Typ, Range_Check) | |
7814 | or else | |
7815 | Is_Check_Suppressed (Typ, Validity_Check)) | |
7816 | then | |
7817 | return True; | |
7818 | end if; | |
7819 | end; | |
7820 | ||
7821 | -- If expression is an entity name, perform checks on this entity | |
7822 | ||
7823 | if Is_Entity_Name (Expr) then | |
7824 | declare | |
7825 | Ent : constant Entity_Id := Entity (Expr); | |
7826 | begin | |
7827 | if Checks_May_Be_Suppressed (Ent) then | |
7828 | return Is_Check_Suppressed (Ent, Range_Check) | |
7829 | or else Is_Check_Suppressed (Ent, Validity_Check); | |
7830 | end if; | |
7831 | end; | |
7832 | end if; | |
7833 | ||
7834 | -- If we fall through, no checks suppressed | |
7835 | ||
7836 | return False; | |
7837 | end Range_Or_Validity_Checks_Suppressed; | |
7838 | ||
226494a3 | 7839 | ------------------- |
7840 | -- Remove_Checks -- | |
7841 | ------------------- | |
7842 | ||
7843 | procedure Remove_Checks (Expr : Node_Id) is | |
226494a3 | 7844 | function Process (N : Node_Id) return Traverse_Result; |
7845 | -- Process a single node during the traversal | |
7846 | ||
8f6e4fd5 | 7847 | procedure Traverse is new Traverse_Proc (Process); |
7848 | -- The traversal procedure itself | |
226494a3 | 7849 | |
7850 | ------------- | |
7851 | -- Process -- | |
7852 | ------------- | |
7853 | ||
7854 | function Process (N : Node_Id) return Traverse_Result is | |
7855 | begin | |
7856 | if Nkind (N) not in N_Subexpr then | |
7857 | return Skip; | |
7858 | end if; | |
7859 | ||
7860 | Set_Do_Range_Check (N, False); | |
7861 | ||
7862 | case Nkind (N) is | |
7863 | when N_And_Then => | |
8f6e4fd5 | 7864 | Traverse (Left_Opnd (N)); |
226494a3 | 7865 | return Skip; |
7866 | ||
7867 | when N_Attribute_Reference => | |
226494a3 | 7868 | Set_Do_Overflow_Check (N, False); |
7869 | ||
226494a3 | 7870 | when N_Function_Call => |
7871 | Set_Do_Tag_Check (N, False); | |
7872 | ||
226494a3 | 7873 | when N_Op => |
7874 | Set_Do_Overflow_Check (N, False); | |
7875 | ||
7876 | case Nkind (N) is | |
7877 | when N_Op_Divide => | |
7878 | Set_Do_Division_Check (N, False); | |
7879 | ||
7880 | when N_Op_And => | |
7881 | Set_Do_Length_Check (N, False); | |
7882 | ||
7883 | when N_Op_Mod => | |
7884 | Set_Do_Division_Check (N, False); | |
7885 | ||
7886 | when N_Op_Or => | |
7887 | Set_Do_Length_Check (N, False); | |
7888 | ||
7889 | when N_Op_Rem => | |
7890 | Set_Do_Division_Check (N, False); | |
7891 | ||
7892 | when N_Op_Xor => | |
7893 | Set_Do_Length_Check (N, False); | |
7894 | ||
7895 | when others => | |
7896 | null; | |
7897 | end case; | |
7898 | ||
7899 | when N_Or_Else => | |
8f6e4fd5 | 7900 | Traverse (Left_Opnd (N)); |
226494a3 | 7901 | return Skip; |
7902 | ||
7903 | when N_Selected_Component => | |
226494a3 | 7904 | Set_Do_Discriminant_Check (N, False); |
7905 | ||
226494a3 | 7906 | when N_Type_Conversion => |
9dfe12ae | 7907 | Set_Do_Length_Check (N, False); |
7908 | Set_Do_Tag_Check (N, False); | |
226494a3 | 7909 | Set_Do_Overflow_Check (N, False); |
226494a3 | 7910 | |
7911 | when others => | |
7912 | null; | |
7913 | end case; | |
7914 | ||
7915 | return OK; | |
7916 | end Process; | |
7917 | ||
7918 | -- Start of processing for Remove_Checks | |
7919 | ||
7920 | begin | |
8f6e4fd5 | 7921 | Traverse (Expr); |
226494a3 | 7922 | end Remove_Checks; |
7923 | ||
ee6ba406 | 7924 | ---------------------------- |
7925 | -- Selected_Length_Checks -- | |
7926 | ---------------------------- | |
7927 | ||
7928 | function Selected_Length_Checks | |
7929 | (Ck_Node : Node_Id; | |
7930 | Target_Typ : Entity_Id; | |
7931 | Source_Typ : Entity_Id; | |
314a23b6 | 7932 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 7933 | is |
7934 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
7935 | S_Typ : Entity_Id; | |
7936 | T_Typ : Entity_Id; | |
7937 | Expr_Actual : Node_Id; | |
7938 | Exptyp : Entity_Id; | |
7939 | Cond : Node_Id := Empty; | |
7940 | Do_Access : Boolean := False; | |
7941 | Wnode : Node_Id := Warn_Node; | |
7942 | Ret_Result : Check_Result := (Empty, Empty); | |
7943 | Num_Checks : Natural := 0; | |
7944 | ||
7945 | procedure Add_Check (N : Node_Id); | |
7946 | -- Adds the action given to Ret_Result if N is non-Empty | |
7947 | ||
7948 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id; | |
7949 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id; | |
314a23b6 | 7950 | -- Comments required ??? |
ee6ba406 | 7951 | |
7952 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean; | |
7953 | -- True for equal literals and for nodes that denote the same constant | |
5f260d20 | 7954 | -- entity, even if its value is not a static constant. This includes the |
9dfe12ae | 7955 | -- case of a discriminal reference within an init proc. Removes some |
5f260d20 | 7956 | -- obviously superfluous checks. |
ee6ba406 | 7957 | |
7958 | function Length_E_Cond | |
7959 | (Exptyp : Entity_Id; | |
7960 | Typ : Entity_Id; | |
314a23b6 | 7961 | Indx : Nat) return Node_Id; |
ee6ba406 | 7962 | -- Returns expression to compute: |
7963 | -- Typ'Length /= Exptyp'Length | |
7964 | ||
7965 | function Length_N_Cond | |
7966 | (Expr : Node_Id; | |
7967 | Typ : Entity_Id; | |
314a23b6 | 7968 | Indx : Nat) return Node_Id; |
ee6ba406 | 7969 | -- Returns expression to compute: |
7970 | -- Typ'Length /= Expr'Length | |
7971 | ||
7972 | --------------- | |
7973 | -- Add_Check -- | |
7974 | --------------- | |
7975 | ||
7976 | procedure Add_Check (N : Node_Id) is | |
7977 | begin | |
7978 | if Present (N) then | |
7979 | ||
7980 | -- For now, ignore attempt to place more than 2 checks ??? | |
7981 | ||
7982 | if Num_Checks = 2 then | |
7983 | return; | |
7984 | end if; | |
7985 | ||
7986 | pragma Assert (Num_Checks <= 1); | |
7987 | Num_Checks := Num_Checks + 1; | |
7988 | Ret_Result (Num_Checks) := N; | |
7989 | end if; | |
7990 | end Add_Check; | |
7991 | ||
7992 | ------------------ | |
7993 | -- Get_E_Length -- | |
7994 | ------------------ | |
7995 | ||
7996 | function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is | |
00c403ee | 7997 | SE : constant Entity_Id := Scope (E); |
ee6ba406 | 7998 | N : Node_Id; |
7999 | E1 : Entity_Id := E; | |
ee6ba406 | 8000 | |
8001 | begin | |
8002 | if Ekind (Scope (E)) = E_Record_Type | |
8003 | and then Has_Discriminants (Scope (E)) | |
8004 | then | |
8005 | N := Build_Discriminal_Subtype_Of_Component (E); | |
8006 | ||
8007 | if Present (N) then | |
8008 | Insert_Action (Ck_Node, N); | |
8009 | E1 := Defining_Identifier (N); | |
8010 | end if; | |
8011 | end if; | |
8012 | ||
8013 | if Ekind (E1) = E_String_Literal_Subtype then | |
8014 | return | |
8015 | Make_Integer_Literal (Loc, | |
8016 | Intval => String_Literal_Length (E1)); | |
8017 | ||
00c403ee | 8018 | elsif SE /= Standard_Standard |
8019 | and then Ekind (Scope (SE)) = E_Protected_Type | |
8020 | and then Has_Discriminants (Scope (SE)) | |
8021 | and then Has_Completion (Scope (SE)) | |
ee6ba406 | 8022 | and then not Inside_Init_Proc |
8023 | then | |
ee6ba406 | 8024 | -- If the type whose length is needed is a private component |
8025 | -- constrained by a discriminant, we must expand the 'Length | |
8026 | -- attribute into an explicit computation, using the discriminal | |
8027 | -- of the current protected operation. This is because the actual | |
8028 | -- type of the prival is constructed after the protected opera- | |
8029 | -- tion has been fully expanded. | |
8030 | ||
8031 | declare | |
8032 | Indx_Type : Node_Id; | |
8033 | Lo : Node_Id; | |
8034 | Hi : Node_Id; | |
8035 | Do_Expand : Boolean := False; | |
8036 | ||
8037 | begin | |
8038 | Indx_Type := First_Index (E); | |
8039 | ||
8040 | for J in 1 .. Indx - 1 loop | |
8041 | Next_Index (Indx_Type); | |
8042 | end loop; | |
8043 | ||
2af58f67 | 8044 | Get_Index_Bounds (Indx_Type, Lo, Hi); |
ee6ba406 | 8045 | |
8046 | if Nkind (Lo) = N_Identifier | |
8047 | and then Ekind (Entity (Lo)) = E_In_Parameter | |
8048 | then | |
8049 | Lo := Get_Discriminal (E, Lo); | |
8050 | Do_Expand := True; | |
8051 | end if; | |
8052 | ||
8053 | if Nkind (Hi) = N_Identifier | |
8054 | and then Ekind (Entity (Hi)) = E_In_Parameter | |
8055 | then | |
8056 | Hi := Get_Discriminal (E, Hi); | |
8057 | Do_Expand := True; | |
8058 | end if; | |
8059 | ||
8060 | if Do_Expand then | |
8061 | if not Is_Entity_Name (Lo) then | |
9dfe12ae | 8062 | Lo := Duplicate_Subexpr_No_Checks (Lo); |
ee6ba406 | 8063 | end if; |
8064 | ||
8065 | if not Is_Entity_Name (Hi) then | |
9dfe12ae | 8066 | Lo := Duplicate_Subexpr_No_Checks (Hi); |
ee6ba406 | 8067 | end if; |
8068 | ||
8069 | N := | |
8070 | Make_Op_Add (Loc, | |
8071 | Left_Opnd => | |
8072 | Make_Op_Subtract (Loc, | |
8073 | Left_Opnd => Hi, | |
8074 | Right_Opnd => Lo), | |
8075 | ||
8076 | Right_Opnd => Make_Integer_Literal (Loc, 1)); | |
8077 | return N; | |
8078 | ||
8079 | else | |
8080 | N := | |
8081 | Make_Attribute_Reference (Loc, | |
8082 | Attribute_Name => Name_Length, | |
8083 | Prefix => | |
8084 | New_Occurrence_Of (E1, Loc)); | |
8085 | ||
8086 | if Indx > 1 then | |
8087 | Set_Expressions (N, New_List ( | |
8088 | Make_Integer_Literal (Loc, Indx))); | |
8089 | end if; | |
8090 | ||
8091 | return N; | |
8092 | end if; | |
8093 | end; | |
8094 | ||
8095 | else | |
8096 | N := | |
8097 | Make_Attribute_Reference (Loc, | |
8098 | Attribute_Name => Name_Length, | |
8099 | Prefix => | |
8100 | New_Occurrence_Of (E1, Loc)); | |
8101 | ||
8102 | if Indx > 1 then | |
8103 | Set_Expressions (N, New_List ( | |
8104 | Make_Integer_Literal (Loc, Indx))); | |
8105 | end if; | |
8106 | ||
8107 | return N; | |
ee6ba406 | 8108 | end if; |
8109 | end Get_E_Length; | |
8110 | ||
8111 | ------------------ | |
8112 | -- Get_N_Length -- | |
8113 | ------------------ | |
8114 | ||
8115 | function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is | |
8116 | begin | |
8117 | return | |
8118 | Make_Attribute_Reference (Loc, | |
8119 | Attribute_Name => Name_Length, | |
8120 | Prefix => | |
9dfe12ae | 8121 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 8122 | Expressions => New_List ( |
8123 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 8124 | end Get_N_Length; |
8125 | ||
8126 | ------------------- | |
8127 | -- Length_E_Cond -- | |
8128 | ------------------- | |
8129 | ||
8130 | function Length_E_Cond | |
8131 | (Exptyp : Entity_Id; | |
8132 | Typ : Entity_Id; | |
314a23b6 | 8133 | Indx : Nat) return Node_Id |
ee6ba406 | 8134 | is |
8135 | begin | |
8136 | return | |
8137 | Make_Op_Ne (Loc, | |
8138 | Left_Opnd => Get_E_Length (Typ, Indx), | |
8139 | Right_Opnd => Get_E_Length (Exptyp, Indx)); | |
ee6ba406 | 8140 | end Length_E_Cond; |
8141 | ||
8142 | ------------------- | |
8143 | -- Length_N_Cond -- | |
8144 | ------------------- | |
8145 | ||
8146 | function Length_N_Cond | |
8147 | (Expr : Node_Id; | |
8148 | Typ : Entity_Id; | |
314a23b6 | 8149 | Indx : Nat) return Node_Id |
ee6ba406 | 8150 | is |
8151 | begin | |
8152 | return | |
8153 | Make_Op_Ne (Loc, | |
8154 | Left_Opnd => Get_E_Length (Typ, Indx), | |
8155 | Right_Opnd => Get_N_Length (Expr, Indx)); | |
ee6ba406 | 8156 | end Length_N_Cond; |
8157 | ||
feff2f05 | 8158 | ----------------- |
8159 | -- Same_Bounds -- | |
8160 | ----------------- | |
8161 | ||
ee6ba406 | 8162 | function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is |
8163 | begin | |
8164 | return | |
8165 | (Nkind (L) = N_Integer_Literal | |
8166 | and then Nkind (R) = N_Integer_Literal | |
8167 | and then Intval (L) = Intval (R)) | |
8168 | ||
8169 | or else | |
8170 | (Is_Entity_Name (L) | |
8171 | and then Ekind (Entity (L)) = E_Constant | |
8172 | and then ((Is_Entity_Name (R) | |
8173 | and then Entity (L) = Entity (R)) | |
8174 | or else | |
8175 | (Nkind (R) = N_Type_Conversion | |
8176 | and then Is_Entity_Name (Expression (R)) | |
8177 | and then Entity (L) = Entity (Expression (R))))) | |
8178 | ||
8179 | or else | |
8180 | (Is_Entity_Name (R) | |
8181 | and then Ekind (Entity (R)) = E_Constant | |
8182 | and then Nkind (L) = N_Type_Conversion | |
8183 | and then Is_Entity_Name (Expression (L)) | |
5f260d20 | 8184 | and then Entity (R) = Entity (Expression (L))) |
8185 | ||
8186 | or else | |
8187 | (Is_Entity_Name (L) | |
8188 | and then Is_Entity_Name (R) | |
8189 | and then Entity (L) = Entity (R) | |
8190 | and then Ekind (Entity (L)) = E_In_Parameter | |
8191 | and then Inside_Init_Proc); | |
ee6ba406 | 8192 | end Same_Bounds; |
8193 | ||
8194 | -- Start of processing for Selected_Length_Checks | |
8195 | ||
8196 | begin | |
6dbcfcd9 | 8197 | if not Full_Expander_Active then |
ee6ba406 | 8198 | return Ret_Result; |
8199 | end if; | |
8200 | ||
8201 | if Target_Typ = Any_Type | |
8202 | or else Target_Typ = Any_Composite | |
8203 | or else Raises_Constraint_Error (Ck_Node) | |
8204 | then | |
8205 | return Ret_Result; | |
8206 | end if; | |
8207 | ||
8208 | if No (Wnode) then | |
8209 | Wnode := Ck_Node; | |
8210 | end if; | |
8211 | ||
8212 | T_Typ := Target_Typ; | |
8213 | ||
8214 | if No (Source_Typ) then | |
8215 | S_Typ := Etype (Ck_Node); | |
8216 | else | |
8217 | S_Typ := Source_Typ; | |
8218 | end if; | |
8219 | ||
8220 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
8221 | return Ret_Result; | |
8222 | end if; | |
8223 | ||
8224 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
8225 | S_Typ := Designated_Type (S_Typ); | |
8226 | T_Typ := Designated_Type (T_Typ); | |
8227 | Do_Access := True; | |
8228 | ||
2af58f67 | 8229 | -- A simple optimization for the null case |
ee6ba406 | 8230 | |
2af58f67 | 8231 | if Known_Null (Ck_Node) then |
ee6ba406 | 8232 | return Ret_Result; |
8233 | end if; | |
8234 | end if; | |
8235 | ||
8236 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
8237 | if Is_Constrained (T_Typ) then | |
8238 | ||
92f1631f | 8239 | -- The checking code to be generated will freeze the corresponding |
8240 | -- array type. However, we must freeze the type now, so that the | |
8241 | -- freeze node does not appear within the generated if expression, | |
8242 | -- but ahead of it. | |
ee6ba406 | 8243 | |
8244 | Freeze_Before (Ck_Node, T_Typ); | |
8245 | ||
8246 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
84d0d4a5 | 8247 | Exptyp := Get_Actual_Subtype (Ck_Node); |
ee6ba406 | 8248 | |
8249 | if Is_Access_Type (Exptyp) then | |
8250 | Exptyp := Designated_Type (Exptyp); | |
8251 | end if; | |
8252 | ||
8253 | -- String_Literal case. This needs to be handled specially be- | |
8254 | -- cause no index types are available for string literals. The | |
8255 | -- condition is simply: | |
8256 | ||
8257 | -- T_Typ'Length = string-literal-length | |
8258 | ||
9dfe12ae | 8259 | if Nkind (Expr_Actual) = N_String_Literal |
8260 | and then Ekind (Etype (Expr_Actual)) = E_String_Literal_Subtype | |
8261 | then | |
ee6ba406 | 8262 | Cond := |
8263 | Make_Op_Ne (Loc, | |
8264 | Left_Opnd => Get_E_Length (T_Typ, 1), | |
8265 | Right_Opnd => | |
8266 | Make_Integer_Literal (Loc, | |
8267 | Intval => | |
8268 | String_Literal_Length (Etype (Expr_Actual)))); | |
8269 | ||
8270 | -- General array case. Here we have a usable actual subtype for | |
8271 | -- the expression, and the condition is built from the two types | |
8272 | -- (Do_Length): | |
8273 | ||
8274 | -- T_Typ'Length /= Exptyp'Length or else | |
8275 | -- T_Typ'Length (2) /= Exptyp'Length (2) or else | |
8276 | -- T_Typ'Length (3) /= Exptyp'Length (3) or else | |
8277 | -- ... | |
8278 | ||
8279 | elsif Is_Constrained (Exptyp) then | |
8280 | declare | |
9dfe12ae | 8281 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
8282 | ||
8283 | L_Index : Node_Id; | |
8284 | R_Index : Node_Id; | |
8285 | L_Low : Node_Id; | |
8286 | L_High : Node_Id; | |
8287 | R_Low : Node_Id; | |
8288 | R_High : Node_Id; | |
ee6ba406 | 8289 | L_Length : Uint; |
8290 | R_Length : Uint; | |
9dfe12ae | 8291 | Ref_Node : Node_Id; |
ee6ba406 | 8292 | |
8293 | begin | |
feff2f05 | 8294 | -- At the library level, we need to ensure that the type of |
8295 | -- the object is elaborated before the check itself is | |
8296 | -- emitted. This is only done if the object is in the | |
8297 | -- current compilation unit, otherwise the type is frozen | |
8298 | -- and elaborated in its unit. | |
9dfe12ae | 8299 | |
8300 | if Is_Itype (Exptyp) | |
8301 | and then | |
8302 | Ekind (Cunit_Entity (Current_Sem_Unit)) = E_Package | |
8303 | and then | |
8304 | not In_Package_Body (Cunit_Entity (Current_Sem_Unit)) | |
d66aa9f6 | 8305 | and then In_Open_Scopes (Scope (Exptyp)) |
9dfe12ae | 8306 | then |
8307 | Ref_Node := Make_Itype_Reference (Sloc (Ck_Node)); | |
8308 | Set_Itype (Ref_Node, Exptyp); | |
8309 | Insert_Action (Ck_Node, Ref_Node); | |
8310 | end if; | |
8311 | ||
ee6ba406 | 8312 | L_Index := First_Index (T_Typ); |
8313 | R_Index := First_Index (Exptyp); | |
8314 | ||
8315 | for Indx in 1 .. Ndims loop | |
8316 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 8317 | or else |
8318 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 8319 | then |
8320 | Get_Index_Bounds (L_Index, L_Low, L_High); | |
8321 | Get_Index_Bounds (R_Index, R_Low, R_High); | |
8322 | ||
8323 | -- Deal with compile time length check. Note that we | |
8324 | -- skip this in the access case, because the access | |
8325 | -- value may be null, so we cannot know statically. | |
8326 | ||
8327 | if not Do_Access | |
8328 | and then Compile_Time_Known_Value (L_Low) | |
8329 | and then Compile_Time_Known_Value (L_High) | |
8330 | and then Compile_Time_Known_Value (R_Low) | |
8331 | and then Compile_Time_Known_Value (R_High) | |
8332 | then | |
8333 | if Expr_Value (L_High) >= Expr_Value (L_Low) then | |
8334 | L_Length := Expr_Value (L_High) - | |
8335 | Expr_Value (L_Low) + 1; | |
8336 | else | |
8337 | L_Length := UI_From_Int (0); | |
8338 | end if; | |
8339 | ||
8340 | if Expr_Value (R_High) >= Expr_Value (R_Low) then | |
8341 | R_Length := Expr_Value (R_High) - | |
8342 | Expr_Value (R_Low) + 1; | |
8343 | else | |
8344 | R_Length := UI_From_Int (0); | |
8345 | end if; | |
8346 | ||
8347 | if L_Length > R_Length then | |
8348 | Add_Check | |
8349 | (Compile_Time_Constraint_Error | |
cb97ae5c | 8350 | (Wnode, "too few elements for}??", T_Typ)); |
ee6ba406 | 8351 | |
8352 | elsif L_Length < R_Length then | |
8353 | Add_Check | |
8354 | (Compile_Time_Constraint_Error | |
cb97ae5c | 8355 | (Wnode, "too many elements for}??", T_Typ)); |
ee6ba406 | 8356 | end if; |
8357 | ||
8358 | -- The comparison for an individual index subtype | |
8359 | -- is omitted if the corresponding index subtypes | |
8360 | -- statically match, since the result is known to | |
8361 | -- be true. Note that this test is worth while even | |
8362 | -- though we do static evaluation, because non-static | |
8363 | -- subtypes can statically match. | |
8364 | ||
8365 | elsif not | |
8366 | Subtypes_Statically_Match | |
8367 | (Etype (L_Index), Etype (R_Index)) | |
8368 | ||
8369 | and then not | |
8370 | (Same_Bounds (L_Low, R_Low) | |
8371 | and then Same_Bounds (L_High, R_High)) | |
8372 | then | |
8373 | Evolve_Or_Else | |
8374 | (Cond, Length_E_Cond (Exptyp, T_Typ, Indx)); | |
8375 | end if; | |
8376 | ||
8377 | Next (L_Index); | |
8378 | Next (R_Index); | |
8379 | end if; | |
8380 | end loop; | |
8381 | end; | |
8382 | ||
8383 | -- Handle cases where we do not get a usable actual subtype that | |
8384 | -- is constrained. This happens for example in the function call | |
8385 | -- and explicit dereference cases. In these cases, we have to get | |
8386 | -- the length or range from the expression itself, making sure we | |
8387 | -- do not evaluate it more than once. | |
8388 | ||
8389 | -- Here Ck_Node is the original expression, or more properly the | |
feff2f05 | 8390 | -- result of applying Duplicate_Expr to the original tree, forcing |
8391 | -- the result to be a name. | |
ee6ba406 | 8392 | |
8393 | else | |
8394 | declare | |
9dfe12ae | 8395 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 8396 | |
8397 | begin | |
8398 | -- Build the condition for the explicit dereference case | |
8399 | ||
8400 | for Indx in 1 .. Ndims loop | |
8401 | Evolve_Or_Else | |
8402 | (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx)); | |
8403 | end loop; | |
8404 | end; | |
8405 | end if; | |
8406 | end if; | |
8407 | end if; | |
8408 | ||
8409 | -- Construct the test and insert into the tree | |
8410 | ||
8411 | if Present (Cond) then | |
8412 | if Do_Access then | |
8413 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
8414 | end if; | |
8415 | ||
f15731c4 | 8416 | Add_Check |
8417 | (Make_Raise_Constraint_Error (Loc, | |
8418 | Condition => Cond, | |
8419 | Reason => CE_Length_Check_Failed)); | |
ee6ba406 | 8420 | end if; |
8421 | ||
8422 | return Ret_Result; | |
ee6ba406 | 8423 | end Selected_Length_Checks; |
8424 | ||
8425 | --------------------------- | |
8426 | -- Selected_Range_Checks -- | |
8427 | --------------------------- | |
8428 | ||
8429 | function Selected_Range_Checks | |
8430 | (Ck_Node : Node_Id; | |
8431 | Target_Typ : Entity_Id; | |
8432 | Source_Typ : Entity_Id; | |
314a23b6 | 8433 | Warn_Node : Node_Id) return Check_Result |
ee6ba406 | 8434 | is |
8435 | Loc : constant Source_Ptr := Sloc (Ck_Node); | |
8436 | S_Typ : Entity_Id; | |
8437 | T_Typ : Entity_Id; | |
8438 | Expr_Actual : Node_Id; | |
8439 | Exptyp : Entity_Id; | |
8440 | Cond : Node_Id := Empty; | |
8441 | Do_Access : Boolean := False; | |
8442 | Wnode : Node_Id := Warn_Node; | |
8443 | Ret_Result : Check_Result := (Empty, Empty); | |
8444 | Num_Checks : Integer := 0; | |
8445 | ||
8446 | procedure Add_Check (N : Node_Id); | |
8447 | -- Adds the action given to Ret_Result if N is non-Empty | |
8448 | ||
8449 | function Discrete_Range_Cond | |
8450 | (Expr : Node_Id; | |
314a23b6 | 8451 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 8452 | -- Returns expression to compute: |
8453 | -- Low_Bound (Expr) < Typ'First | |
8454 | -- or else | |
8455 | -- High_Bound (Expr) > Typ'Last | |
8456 | ||
8457 | function Discrete_Expr_Cond | |
8458 | (Expr : Node_Id; | |
314a23b6 | 8459 | Typ : Entity_Id) return Node_Id; |
ee6ba406 | 8460 | -- Returns expression to compute: |
8461 | -- Expr < Typ'First | |
8462 | -- or else | |
8463 | -- Expr > Typ'Last | |
8464 | ||
8465 | function Get_E_First_Or_Last | |
3cb12758 | 8466 | (Loc : Source_Ptr; |
8467 | E : Entity_Id; | |
ee6ba406 | 8468 | Indx : Nat; |
314a23b6 | 8469 | Nam : Name_Id) return Node_Id; |
79212397 | 8470 | -- Returns an attribute reference |
ee6ba406 | 8471 | -- E'First or E'Last |
79212397 | 8472 | -- with a source location of Loc. |
f73ee678 | 8473 | -- |
79212397 | 8474 | -- Nam is Name_First or Name_Last, according to which attribute is |
8475 | -- desired. If Indx is non-zero, it is passed as a literal in the | |
8476 | -- Expressions of the attribute reference (identifying the desired | |
8477 | -- array dimension). | |
ee6ba406 | 8478 | |
8479 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id; | |
8480 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id; | |
8481 | -- Returns expression to compute: | |
9dfe12ae | 8482 | -- N'First or N'Last using Duplicate_Subexpr_No_Checks |
ee6ba406 | 8483 | |
8484 | function Range_E_Cond | |
8485 | (Exptyp : Entity_Id; | |
8486 | Typ : Entity_Id; | |
8487 | Indx : Nat) | |
8488 | return Node_Id; | |
8489 | -- Returns expression to compute: | |
8490 | -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last | |
8491 | ||
8492 | function Range_Equal_E_Cond | |
8493 | (Exptyp : Entity_Id; | |
8494 | Typ : Entity_Id; | |
314a23b6 | 8495 | Indx : Nat) return Node_Id; |
ee6ba406 | 8496 | -- Returns expression to compute: |
8497 | -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last | |
8498 | ||
8499 | function Range_N_Cond | |
8500 | (Expr : Node_Id; | |
8501 | Typ : Entity_Id; | |
314a23b6 | 8502 | Indx : Nat) return Node_Id; |
ee6ba406 | 8503 | -- Return expression to compute: |
8504 | -- Expr'First < Typ'First or else Expr'Last > Typ'Last | |
8505 | ||
8506 | --------------- | |
8507 | -- Add_Check -- | |
8508 | --------------- | |
8509 | ||
8510 | procedure Add_Check (N : Node_Id) is | |
8511 | begin | |
8512 | if Present (N) then | |
8513 | ||
8514 | -- For now, ignore attempt to place more than 2 checks ??? | |
8515 | ||
8516 | if Num_Checks = 2 then | |
8517 | return; | |
8518 | end if; | |
8519 | ||
8520 | pragma Assert (Num_Checks <= 1); | |
8521 | Num_Checks := Num_Checks + 1; | |
8522 | Ret_Result (Num_Checks) := N; | |
8523 | end if; | |
8524 | end Add_Check; | |
8525 | ||
8526 | ------------------------- | |
8527 | -- Discrete_Expr_Cond -- | |
8528 | ------------------------- | |
8529 | ||
8530 | function Discrete_Expr_Cond | |
8531 | (Expr : Node_Id; | |
314a23b6 | 8532 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 8533 | is |
8534 | begin | |
8535 | return | |
8536 | Make_Or_Else (Loc, | |
8537 | Left_Opnd => | |
8538 | Make_Op_Lt (Loc, | |
8539 | Left_Opnd => | |
9dfe12ae | 8540 | Convert_To (Base_Type (Typ), |
8541 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 8542 | Right_Opnd => |
8543 | Convert_To (Base_Type (Typ), | |
3cb12758 | 8544 | Get_E_First_Or_Last (Loc, Typ, 0, Name_First))), |
ee6ba406 | 8545 | |
8546 | Right_Opnd => | |
8547 | Make_Op_Gt (Loc, | |
8548 | Left_Opnd => | |
9dfe12ae | 8549 | Convert_To (Base_Type (Typ), |
8550 | Duplicate_Subexpr_No_Checks (Expr)), | |
ee6ba406 | 8551 | Right_Opnd => |
8552 | Convert_To | |
8553 | (Base_Type (Typ), | |
3cb12758 | 8554 | Get_E_First_Or_Last (Loc, Typ, 0, Name_Last)))); |
ee6ba406 | 8555 | end Discrete_Expr_Cond; |
8556 | ||
8557 | ------------------------- | |
8558 | -- Discrete_Range_Cond -- | |
8559 | ------------------------- | |
8560 | ||
8561 | function Discrete_Range_Cond | |
8562 | (Expr : Node_Id; | |
314a23b6 | 8563 | Typ : Entity_Id) return Node_Id |
ee6ba406 | 8564 | is |
8565 | LB : Node_Id := Low_Bound (Expr); | |
8566 | HB : Node_Id := High_Bound (Expr); | |
8567 | ||
8568 | Left_Opnd : Node_Id; | |
8569 | Right_Opnd : Node_Id; | |
8570 | ||
8571 | begin | |
8572 | if Nkind (LB) = N_Identifier | |
feff2f05 | 8573 | and then Ekind (Entity (LB)) = E_Discriminant |
8574 | then | |
ee6ba406 | 8575 | LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc); |
8576 | end if; | |
8577 | ||
ee6ba406 | 8578 | Left_Opnd := |
8579 | Make_Op_Lt (Loc, | |
8580 | Left_Opnd => | |
8581 | Convert_To | |
9dfe12ae | 8582 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (LB)), |
ee6ba406 | 8583 | |
8584 | Right_Opnd => | |
8585 | Convert_To | |
3cb12758 | 8586 | (Base_Type (Typ), |
8587 | Get_E_First_Or_Last (Loc, Typ, 0, Name_First))); | |
ee6ba406 | 8588 | |
ba9b1a39 | 8589 | if Nkind (HB) = N_Identifier |
8590 | and then Ekind (Entity (HB)) = E_Discriminant | |
ee6ba406 | 8591 | then |
ba9b1a39 | 8592 | HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc); |
ee6ba406 | 8593 | end if; |
8594 | ||
8595 | Right_Opnd := | |
8596 | Make_Op_Gt (Loc, | |
8597 | Left_Opnd => | |
8598 | Convert_To | |
9dfe12ae | 8599 | (Base_Type (Typ), Duplicate_Subexpr_No_Checks (HB)), |
ee6ba406 | 8600 | |
8601 | Right_Opnd => | |
8602 | Convert_To | |
8603 | (Base_Type (Typ), | |
3cb12758 | 8604 | Get_E_First_Or_Last (Loc, Typ, 0, Name_Last))); |
ee6ba406 | 8605 | |
8606 | return Make_Or_Else (Loc, Left_Opnd, Right_Opnd); | |
8607 | end Discrete_Range_Cond; | |
8608 | ||
8609 | ------------------------- | |
8610 | -- Get_E_First_Or_Last -- | |
8611 | ------------------------- | |
8612 | ||
8613 | function Get_E_First_Or_Last | |
3cb12758 | 8614 | (Loc : Source_Ptr; |
8615 | E : Entity_Id; | |
ee6ba406 | 8616 | Indx : Nat; |
314a23b6 | 8617 | Nam : Name_Id) return Node_Id |
ee6ba406 | 8618 | is |
3cb12758 | 8619 | Exprs : List_Id; |
ee6ba406 | 8620 | begin |
3cb12758 | 8621 | if Indx > 0 then |
8622 | Exprs := New_List (Make_Integer_Literal (Loc, UI_From_Int (Indx))); | |
ee6ba406 | 8623 | else |
3cb12758 | 8624 | Exprs := No_List; |
ee6ba406 | 8625 | end if; |
8626 | ||
3cb12758 | 8627 | return Make_Attribute_Reference (Loc, |
8628 | Prefix => New_Occurrence_Of (E, Loc), | |
8629 | Attribute_Name => Nam, | |
8630 | Expressions => Exprs); | |
ee6ba406 | 8631 | end Get_E_First_Or_Last; |
8632 | ||
8633 | ----------------- | |
8634 | -- Get_N_First -- | |
8635 | ----------------- | |
8636 | ||
8637 | function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is | |
8638 | begin | |
8639 | return | |
8640 | Make_Attribute_Reference (Loc, | |
8641 | Attribute_Name => Name_First, | |
8642 | Prefix => | |
9dfe12ae | 8643 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 8644 | Expressions => New_List ( |
8645 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 8646 | end Get_N_First; |
8647 | ||
8648 | ---------------- | |
8649 | -- Get_N_Last -- | |
8650 | ---------------- | |
8651 | ||
8652 | function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is | |
8653 | begin | |
8654 | return | |
8655 | Make_Attribute_Reference (Loc, | |
8656 | Attribute_Name => Name_Last, | |
8657 | Prefix => | |
9dfe12ae | 8658 | Duplicate_Subexpr_No_Checks (N, Name_Req => True), |
ee6ba406 | 8659 | Expressions => New_List ( |
8660 | Make_Integer_Literal (Loc, Indx))); | |
ee6ba406 | 8661 | end Get_N_Last; |
8662 | ||
8663 | ------------------ | |
8664 | -- Range_E_Cond -- | |
8665 | ------------------ | |
8666 | ||
8667 | function Range_E_Cond | |
8668 | (Exptyp : Entity_Id; | |
8669 | Typ : Entity_Id; | |
314a23b6 | 8670 | Indx : Nat) return Node_Id |
ee6ba406 | 8671 | is |
8672 | begin | |
8673 | return | |
8674 | Make_Or_Else (Loc, | |
8675 | Left_Opnd => | |
8676 | Make_Op_Lt (Loc, | |
3cb12758 | 8677 | Left_Opnd => |
8678 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First), | |
8679 | Right_Opnd => | |
8680 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
ee6ba406 | 8681 | |
8682 | Right_Opnd => | |
8683 | Make_Op_Gt (Loc, | |
3cb12758 | 8684 | Left_Opnd => |
8685 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last), | |
8686 | Right_Opnd => | |
8687 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 8688 | end Range_E_Cond; |
8689 | ||
8690 | ------------------------ | |
8691 | -- Range_Equal_E_Cond -- | |
8692 | ------------------------ | |
8693 | ||
8694 | function Range_Equal_E_Cond | |
8695 | (Exptyp : Entity_Id; | |
8696 | Typ : Entity_Id; | |
314a23b6 | 8697 | Indx : Nat) return Node_Id |
ee6ba406 | 8698 | is |
8699 | begin | |
8700 | return | |
8701 | Make_Or_Else (Loc, | |
8702 | Left_Opnd => | |
8703 | Make_Op_Ne (Loc, | |
3cb12758 | 8704 | Left_Opnd => |
8705 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First), | |
8706 | Right_Opnd => | |
8707 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
8708 | ||
ee6ba406 | 8709 | Right_Opnd => |
8710 | Make_Op_Ne (Loc, | |
3cb12758 | 8711 | Left_Opnd => |
8712 | Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last), | |
8713 | Right_Opnd => | |
8714 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 8715 | end Range_Equal_E_Cond; |
8716 | ||
8717 | ------------------ | |
8718 | -- Range_N_Cond -- | |
8719 | ------------------ | |
8720 | ||
8721 | function Range_N_Cond | |
8722 | (Expr : Node_Id; | |
8723 | Typ : Entity_Id; | |
314a23b6 | 8724 | Indx : Nat) return Node_Id |
ee6ba406 | 8725 | is |
8726 | begin | |
8727 | return | |
8728 | Make_Or_Else (Loc, | |
8729 | Left_Opnd => | |
8730 | Make_Op_Lt (Loc, | |
3cb12758 | 8731 | Left_Opnd => |
8732 | Get_N_First (Expr, Indx), | |
8733 | Right_Opnd => | |
8734 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)), | |
ee6ba406 | 8735 | |
8736 | Right_Opnd => | |
8737 | Make_Op_Gt (Loc, | |
3cb12758 | 8738 | Left_Opnd => |
8739 | Get_N_Last (Expr, Indx), | |
8740 | Right_Opnd => | |
8741 | Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last))); | |
ee6ba406 | 8742 | end Range_N_Cond; |
8743 | ||
8744 | -- Start of processing for Selected_Range_Checks | |
8745 | ||
8746 | begin | |
6dbcfcd9 | 8747 | if not Full_Expander_Active then |
ee6ba406 | 8748 | return Ret_Result; |
8749 | end if; | |
8750 | ||
8751 | if Target_Typ = Any_Type | |
8752 | or else Target_Typ = Any_Composite | |
8753 | or else Raises_Constraint_Error (Ck_Node) | |
8754 | then | |
8755 | return Ret_Result; | |
8756 | end if; | |
8757 | ||
8758 | if No (Wnode) then | |
8759 | Wnode := Ck_Node; | |
8760 | end if; | |
8761 | ||
8762 | T_Typ := Target_Typ; | |
8763 | ||
8764 | if No (Source_Typ) then | |
8765 | S_Typ := Etype (Ck_Node); | |
8766 | else | |
8767 | S_Typ := Source_Typ; | |
8768 | end if; | |
8769 | ||
8770 | if S_Typ = Any_Type or else S_Typ = Any_Composite then | |
8771 | return Ret_Result; | |
8772 | end if; | |
8773 | ||
8774 | -- The order of evaluating T_Typ before S_Typ seems to be critical | |
8775 | -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed | |
8776 | -- in, and since Node can be an N_Range node, it might be invalid. | |
8777 | -- Should there be an assert check somewhere for taking the Etype of | |
8778 | -- an N_Range node ??? | |
8779 | ||
8780 | if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then | |
8781 | S_Typ := Designated_Type (S_Typ); | |
8782 | T_Typ := Designated_Type (T_Typ); | |
8783 | Do_Access := True; | |
8784 | ||
2af58f67 | 8785 | -- A simple optimization for the null case |
ee6ba406 | 8786 | |
2af58f67 | 8787 | if Known_Null (Ck_Node) then |
ee6ba406 | 8788 | return Ret_Result; |
8789 | end if; | |
8790 | end if; | |
8791 | ||
8792 | -- For an N_Range Node, check for a null range and then if not | |
8793 | -- null generate a range check action. | |
8794 | ||
8795 | if Nkind (Ck_Node) = N_Range then | |
8796 | ||
8797 | -- There's no point in checking a range against itself | |
8798 | ||
8799 | if Ck_Node = Scalar_Range (T_Typ) then | |
8800 | return Ret_Result; | |
8801 | end if; | |
8802 | ||
8803 | declare | |
8804 | T_LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
8805 | T_HB : constant Node_Id := Type_High_Bound (T_Typ); | |
eefa141b | 8806 | Known_T_LB : constant Boolean := Compile_Time_Known_Value (T_LB); |
8807 | Known_T_HB : constant Boolean := Compile_Time_Known_Value (T_HB); | |
ee6ba406 | 8808 | |
eefa141b | 8809 | LB : Node_Id := Low_Bound (Ck_Node); |
8810 | HB : Node_Id := High_Bound (Ck_Node); | |
8811 | Known_LB : Boolean; | |
8812 | Known_HB : Boolean; | |
8813 | ||
8814 | Null_Range : Boolean; | |
ee6ba406 | 8815 | Out_Of_Range_L : Boolean; |
8816 | Out_Of_Range_H : Boolean; | |
8817 | ||
8818 | begin | |
eefa141b | 8819 | -- Compute what is known at compile time |
8820 | ||
8821 | if Known_T_LB and Known_T_HB then | |
8822 | if Compile_Time_Known_Value (LB) then | |
8823 | Known_LB := True; | |
8824 | ||
8825 | -- There's no point in checking that a bound is within its | |
8826 | -- own range so pretend that it is known in this case. First | |
8827 | -- deal with low bound. | |
8828 | ||
8829 | elsif Ekind (Etype (LB)) = E_Signed_Integer_Subtype | |
8830 | and then Scalar_Range (Etype (LB)) = Scalar_Range (T_Typ) | |
8831 | then | |
8832 | LB := T_LB; | |
8833 | Known_LB := True; | |
8834 | ||
8835 | else | |
8836 | Known_LB := False; | |
8837 | end if; | |
8838 | ||
8839 | -- Likewise for the high bound | |
8840 | ||
8841 | if Compile_Time_Known_Value (HB) then | |
8842 | Known_HB := True; | |
8843 | ||
8844 | elsif Ekind (Etype (HB)) = E_Signed_Integer_Subtype | |
8845 | and then Scalar_Range (Etype (HB)) = Scalar_Range (T_Typ) | |
8846 | then | |
8847 | HB := T_HB; | |
8848 | Known_HB := True; | |
8849 | ||
8850 | else | |
8851 | Known_HB := False; | |
8852 | end if; | |
8853 | end if; | |
8854 | ||
8855 | -- Check for case where everything is static and we can do the | |
8856 | -- check at compile time. This is skipped if we have an access | |
8857 | -- type, since the access value may be null. | |
8858 | ||
8859 | -- ??? This code can be improved since you only need to know that | |
8860 | -- the two respective bounds (LB & T_LB or HB & T_HB) are known at | |
8861 | -- compile time to emit pertinent messages. | |
8862 | ||
8863 | if Known_T_LB and Known_T_HB and Known_LB and Known_HB | |
8864 | and not Do_Access | |
ee6ba406 | 8865 | then |
8866 | -- Floating-point case | |
8867 | ||
8868 | if Is_Floating_Point_Type (S_Typ) then | |
8869 | Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB); | |
8870 | Out_Of_Range_L := | |
8871 | (Expr_Value_R (LB) < Expr_Value_R (T_LB)) | |
eefa141b | 8872 | or else |
ee6ba406 | 8873 | (Expr_Value_R (LB) > Expr_Value_R (T_HB)); |
8874 | ||
8875 | Out_Of_Range_H := | |
8876 | (Expr_Value_R (HB) > Expr_Value_R (T_HB)) | |
eefa141b | 8877 | or else |
ee6ba406 | 8878 | (Expr_Value_R (HB) < Expr_Value_R (T_LB)); |
8879 | ||
8880 | -- Fixed or discrete type case | |
8881 | ||
8882 | else | |
8883 | Null_Range := Expr_Value (HB) < Expr_Value (LB); | |
8884 | Out_Of_Range_L := | |
8885 | (Expr_Value (LB) < Expr_Value (T_LB)) | |
eefa141b | 8886 | or else |
ee6ba406 | 8887 | (Expr_Value (LB) > Expr_Value (T_HB)); |
8888 | ||
8889 | Out_Of_Range_H := | |
8890 | (Expr_Value (HB) > Expr_Value (T_HB)) | |
eefa141b | 8891 | or else |
ee6ba406 | 8892 | (Expr_Value (HB) < Expr_Value (T_LB)); |
8893 | end if; | |
8894 | ||
8895 | if not Null_Range then | |
8896 | if Out_Of_Range_L then | |
8897 | if No (Warn_Node) then | |
8898 | Add_Check | |
8899 | (Compile_Time_Constraint_Error | |
8900 | (Low_Bound (Ck_Node), | |
cb97ae5c | 8901 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 8902 | |
8903 | else | |
8904 | Add_Check | |
8905 | (Compile_Time_Constraint_Error | |
8906 | (Wnode, | |
cb97ae5c | 8907 | "static range out of bounds of}??", T_Typ)); |
ee6ba406 | 8908 | end if; |
8909 | end if; | |
8910 | ||
8911 | if Out_Of_Range_H then | |
8912 | if No (Warn_Node) then | |
8913 | Add_Check | |
8914 | (Compile_Time_Constraint_Error | |
8915 | (High_Bound (Ck_Node), | |
cb97ae5c | 8916 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 8917 | |
8918 | else | |
8919 | Add_Check | |
8920 | (Compile_Time_Constraint_Error | |
8921 | (Wnode, | |
cb97ae5c | 8922 | "static range out of bounds of}??", T_Typ)); |
ee6ba406 | 8923 | end if; |
8924 | end if; | |
ee6ba406 | 8925 | end if; |
8926 | ||
8927 | else | |
8928 | declare | |
8929 | LB : Node_Id := Low_Bound (Ck_Node); | |
8930 | HB : Node_Id := High_Bound (Ck_Node); | |
8931 | ||
8932 | begin | |
feff2f05 | 8933 | -- If either bound is a discriminant and we are within the |
8934 | -- record declaration, it is a use of the discriminant in a | |
8935 | -- constraint of a component, and nothing can be checked | |
8936 | -- here. The check will be emitted within the init proc. | |
8937 | -- Before then, the discriminal has no real meaning. | |
8938 | -- Similarly, if the entity is a discriminal, there is no | |
8939 | -- check to perform yet. | |
8940 | ||
8941 | -- The same holds within a discriminated synchronized type, | |
8942 | -- where the discriminant may constrain a component or an | |
8943 | -- entry family. | |
ee6ba406 | 8944 | |
8945 | if Nkind (LB) = N_Identifier | |
0577b0b1 | 8946 | and then Denotes_Discriminant (LB, True) |
ee6ba406 | 8947 | then |
0577b0b1 | 8948 | if Current_Scope = Scope (Entity (LB)) |
8949 | or else Is_Concurrent_Type (Current_Scope) | |
8950 | or else Ekind (Entity (LB)) /= E_Discriminant | |
8951 | then | |
ee6ba406 | 8952 | return Ret_Result; |
8953 | else | |
8954 | LB := | |
8955 | New_Occurrence_Of (Discriminal (Entity (LB)), Loc); | |
8956 | end if; | |
8957 | end if; | |
8958 | ||
8959 | if Nkind (HB) = N_Identifier | |
0577b0b1 | 8960 | and then Denotes_Discriminant (HB, True) |
ee6ba406 | 8961 | then |
0577b0b1 | 8962 | if Current_Scope = Scope (Entity (HB)) |
8963 | or else Is_Concurrent_Type (Current_Scope) | |
8964 | or else Ekind (Entity (HB)) /= E_Discriminant | |
8965 | then | |
ee6ba406 | 8966 | return Ret_Result; |
8967 | else | |
8968 | HB := | |
8969 | New_Occurrence_Of (Discriminal (Entity (HB)), Loc); | |
8970 | end if; | |
8971 | end if; | |
8972 | ||
8973 | Cond := Discrete_Range_Cond (Ck_Node, T_Typ); | |
8974 | Set_Paren_Count (Cond, 1); | |
8975 | ||
8976 | Cond := | |
8977 | Make_And_Then (Loc, | |
8978 | Left_Opnd => | |
8979 | Make_Op_Ge (Loc, | |
9dfe12ae | 8980 | Left_Opnd => Duplicate_Subexpr_No_Checks (HB), |
8981 | Right_Opnd => Duplicate_Subexpr_No_Checks (LB)), | |
ee6ba406 | 8982 | Right_Opnd => Cond); |
8983 | end; | |
ee6ba406 | 8984 | end if; |
8985 | end; | |
8986 | ||
8987 | elsif Is_Scalar_Type (S_Typ) then | |
8988 | ||
8989 | -- This somewhat duplicates what Apply_Scalar_Range_Check does, | |
8990 | -- except the above simply sets a flag in the node and lets | |
8991 | -- gigi generate the check base on the Etype of the expression. | |
8992 | -- Sometimes, however we want to do a dynamic check against an | |
8993 | -- arbitrary target type, so we do that here. | |
8994 | ||
8995 | if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then | |
8996 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
8997 | ||
8998 | -- For literals, we can tell if the constraint error will be | |
8999 | -- raised at compile time, so we never need a dynamic check, but | |
9000 | -- if the exception will be raised, then post the usual warning, | |
9001 | -- and replace the literal with a raise constraint error | |
9002 | -- expression. As usual, skip this for access types | |
9003 | ||
9004 | elsif Compile_Time_Known_Value (Ck_Node) | |
9005 | and then not Do_Access | |
9006 | then | |
9007 | declare | |
9008 | LB : constant Node_Id := Type_Low_Bound (T_Typ); | |
9009 | UB : constant Node_Id := Type_High_Bound (T_Typ); | |
9010 | ||
9011 | Out_Of_Range : Boolean; | |
9012 | Static_Bounds : constant Boolean := | |
b6341c67 | 9013 | Compile_Time_Known_Value (LB) |
9014 | and Compile_Time_Known_Value (UB); | |
ee6ba406 | 9015 | |
9016 | begin | |
9017 | -- Following range tests should use Sem_Eval routine ??? | |
9018 | ||
9019 | if Static_Bounds then | |
9020 | if Is_Floating_Point_Type (S_Typ) then | |
9021 | Out_Of_Range := | |
9022 | (Expr_Value_R (Ck_Node) < Expr_Value_R (LB)) | |
9023 | or else | |
9024 | (Expr_Value_R (Ck_Node) > Expr_Value_R (UB)); | |
9025 | ||
eefa141b | 9026 | -- Fixed or discrete type |
9027 | ||
9028 | else | |
ee6ba406 | 9029 | Out_Of_Range := |
9030 | Expr_Value (Ck_Node) < Expr_Value (LB) | |
9031 | or else | |
9032 | Expr_Value (Ck_Node) > Expr_Value (UB); | |
9033 | end if; | |
9034 | ||
eefa141b | 9035 | -- Bounds of the type are static and the literal is out of |
9036 | -- range so output a warning message. | |
ee6ba406 | 9037 | |
9038 | if Out_Of_Range then | |
9039 | if No (Warn_Node) then | |
9040 | Add_Check | |
9041 | (Compile_Time_Constraint_Error | |
9042 | (Ck_Node, | |
cb97ae5c | 9043 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 9044 | |
9045 | else | |
9046 | Add_Check | |
9047 | (Compile_Time_Constraint_Error | |
9048 | (Wnode, | |
cb97ae5c | 9049 | "static value out of range of}??", T_Typ)); |
ee6ba406 | 9050 | end if; |
9051 | end if; | |
9052 | ||
9053 | else | |
9054 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); | |
9055 | end if; | |
9056 | end; | |
9057 | ||
9058 | -- Here for the case of a non-static expression, we need a runtime | |
9059 | -- check unless the source type range is guaranteed to be in the | |
9060 | -- range of the target type. | |
9061 | ||
9062 | else | |
7a1dabb3 | 9063 | if not In_Subrange_Of (S_Typ, T_Typ) then |
ee6ba406 | 9064 | Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); |
9065 | end if; | |
9066 | end if; | |
9067 | end if; | |
9068 | ||
9069 | if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then | |
9070 | if Is_Constrained (T_Typ) then | |
9071 | ||
9072 | Expr_Actual := Get_Referenced_Object (Ck_Node); | |
9073 | Exptyp := Get_Actual_Subtype (Expr_Actual); | |
9074 | ||
9075 | if Is_Access_Type (Exptyp) then | |
9076 | Exptyp := Designated_Type (Exptyp); | |
9077 | end if; | |
9078 | ||
9079 | -- String_Literal case. This needs to be handled specially be- | |
9080 | -- cause no index types are available for string literals. The | |
9081 | -- condition is simply: | |
9082 | ||
9083 | -- T_Typ'Length = string-literal-length | |
9084 | ||
9085 | if Nkind (Expr_Actual) = N_String_Literal then | |
9086 | null; | |
9087 | ||
9088 | -- General array case. Here we have a usable actual subtype for | |
9089 | -- the expression, and the condition is built from the two types | |
9090 | ||
9091 | -- T_Typ'First < Exptyp'First or else | |
9092 | -- T_Typ'Last > Exptyp'Last or else | |
9093 | -- T_Typ'First(1) < Exptyp'First(1) or else | |
9094 | -- T_Typ'Last(1) > Exptyp'Last(1) or else | |
9095 | -- ... | |
9096 | ||
9097 | elsif Is_Constrained (Exptyp) then | |
9098 | declare | |
9dfe12ae | 9099 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
9100 | ||
ee6ba406 | 9101 | L_Index : Node_Id; |
9102 | R_Index : Node_Id; | |
ee6ba406 | 9103 | |
9104 | begin | |
9105 | L_Index := First_Index (T_Typ); | |
9106 | R_Index := First_Index (Exptyp); | |
9107 | ||
9108 | for Indx in 1 .. Ndims loop | |
9109 | if not (Nkind (L_Index) = N_Raise_Constraint_Error | |
f15731c4 | 9110 | or else |
9111 | Nkind (R_Index) = N_Raise_Constraint_Error) | |
ee6ba406 | 9112 | then |
ee6ba406 | 9113 | -- Deal with compile time length check. Note that we |
9114 | -- skip this in the access case, because the access | |
9115 | -- value may be null, so we cannot know statically. | |
9116 | ||
9117 | if not | |
9118 | Subtypes_Statically_Match | |
9119 | (Etype (L_Index), Etype (R_Index)) | |
9120 | then | |
9121 | -- If the target type is constrained then we | |
9122 | -- have to check for exact equality of bounds | |
9123 | -- (required for qualified expressions). | |
9124 | ||
9125 | if Is_Constrained (T_Typ) then | |
9126 | Evolve_Or_Else | |
9127 | (Cond, | |
9128 | Range_Equal_E_Cond (Exptyp, T_Typ, Indx)); | |
ee6ba406 | 9129 | else |
9130 | Evolve_Or_Else | |
9131 | (Cond, Range_E_Cond (Exptyp, T_Typ, Indx)); | |
9132 | end if; | |
9133 | end if; | |
9134 | ||
9135 | Next (L_Index); | |
9136 | Next (R_Index); | |
ee6ba406 | 9137 | end if; |
9138 | end loop; | |
9139 | end; | |
9140 | ||
9141 | -- Handle cases where we do not get a usable actual subtype that | |
9142 | -- is constrained. This happens for example in the function call | |
9143 | -- and explicit dereference cases. In these cases, we have to get | |
9144 | -- the length or range from the expression itself, making sure we | |
9145 | -- do not evaluate it more than once. | |
9146 | ||
9147 | -- Here Ck_Node is the original expression, or more properly the | |
9148 | -- result of applying Duplicate_Expr to the original tree, | |
9149 | -- forcing the result to be a name. | |
9150 | ||
9151 | else | |
9152 | declare | |
9dfe12ae | 9153 | Ndims : constant Nat := Number_Dimensions (T_Typ); |
ee6ba406 | 9154 | |
9155 | begin | |
9156 | -- Build the condition for the explicit dereference case | |
9157 | ||
9158 | for Indx in 1 .. Ndims loop | |
9159 | Evolve_Or_Else | |
9160 | (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx)); | |
9161 | end loop; | |
9162 | end; | |
ee6ba406 | 9163 | end if; |
9164 | ||
9165 | else | |
feff2f05 | 9166 | -- For a conversion to an unconstrained array type, generate an |
9167 | -- Action to check that the bounds of the source value are within | |
9168 | -- the constraints imposed by the target type (RM 4.6(38)). No | |
9169 | -- check is needed for a conversion to an access to unconstrained | |
9170 | -- array type, as 4.6(24.15/2) requires the designated subtypes | |
9171 | -- of the two access types to statically match. | |
9172 | ||
9173 | if Nkind (Parent (Ck_Node)) = N_Type_Conversion | |
9174 | and then not Do_Access | |
9175 | then | |
ee6ba406 | 9176 | declare |
9177 | Opnd_Index : Node_Id; | |
9178 | Targ_Index : Node_Id; | |
00c403ee | 9179 | Opnd_Range : Node_Id; |
ee6ba406 | 9180 | |
9181 | begin | |
feff2f05 | 9182 | Opnd_Index := First_Index (Get_Actual_Subtype (Ck_Node)); |
ee6ba406 | 9183 | Targ_Index := First_Index (T_Typ); |
00c403ee | 9184 | while Present (Opnd_Index) loop |
9185 | ||
9186 | -- If the index is a range, use its bounds. If it is an | |
9187 | -- entity (as will be the case if it is a named subtype | |
9188 | -- or an itype created for a slice) retrieve its range. | |
9189 | ||
9190 | if Is_Entity_Name (Opnd_Index) | |
9191 | and then Is_Type (Entity (Opnd_Index)) | |
9192 | then | |
9193 | Opnd_Range := Scalar_Range (Entity (Opnd_Index)); | |
9194 | else | |
9195 | Opnd_Range := Opnd_Index; | |
9196 | end if; | |
9197 | ||
9198 | if Nkind (Opnd_Range) = N_Range then | |
9c486805 | 9199 | if Is_In_Range |
9200 | (Low_Bound (Opnd_Range), Etype (Targ_Index), | |
9201 | Assume_Valid => True) | |
ee6ba406 | 9202 | and then |
9203 | Is_In_Range | |
9c486805 | 9204 | (High_Bound (Opnd_Range), Etype (Targ_Index), |
9205 | Assume_Valid => True) | |
ee6ba406 | 9206 | then |
9207 | null; | |
9208 | ||
feff2f05 | 9209 | -- If null range, no check needed |
f2a06be9 | 9210 | |
9dfe12ae | 9211 | elsif |
00c403ee | 9212 | Compile_Time_Known_Value (High_Bound (Opnd_Range)) |
9dfe12ae | 9213 | and then |
00c403ee | 9214 | Compile_Time_Known_Value (Low_Bound (Opnd_Range)) |
9dfe12ae | 9215 | and then |
00c403ee | 9216 | Expr_Value (High_Bound (Opnd_Range)) < |
9217 | Expr_Value (Low_Bound (Opnd_Range)) | |
9dfe12ae | 9218 | then |
9219 | null; | |
9220 | ||
ee6ba406 | 9221 | elsif Is_Out_Of_Range |
9c486805 | 9222 | (Low_Bound (Opnd_Range), Etype (Targ_Index), |
9223 | Assume_Valid => True) | |
ee6ba406 | 9224 | or else |
9225 | Is_Out_Of_Range | |
9c486805 | 9226 | (High_Bound (Opnd_Range), Etype (Targ_Index), |
9227 | Assume_Valid => True) | |
ee6ba406 | 9228 | then |
9229 | Add_Check | |
9230 | (Compile_Time_Constraint_Error | |
cb97ae5c | 9231 | (Wnode, "value out of range of}??", T_Typ)); |
ee6ba406 | 9232 | |
9233 | else | |
9234 | Evolve_Or_Else | |
9235 | (Cond, | |
9236 | Discrete_Range_Cond | |
00c403ee | 9237 | (Opnd_Range, Etype (Targ_Index))); |
ee6ba406 | 9238 | end if; |
9239 | end if; | |
9240 | ||
9241 | Next_Index (Opnd_Index); | |
9242 | Next_Index (Targ_Index); | |
9243 | end loop; | |
9244 | end; | |
9245 | end if; | |
9246 | end if; | |
9247 | end if; | |
9248 | ||
9249 | -- Construct the test and insert into the tree | |
9250 | ||
9251 | if Present (Cond) then | |
9252 | if Do_Access then | |
9253 | Cond := Guard_Access (Cond, Loc, Ck_Node); | |
9254 | end if; | |
9255 | ||
f15731c4 | 9256 | Add_Check |
9257 | (Make_Raise_Constraint_Error (Loc, | |
eefa141b | 9258 | Condition => Cond, |
9259 | Reason => CE_Range_Check_Failed)); | |
ee6ba406 | 9260 | end if; |
9261 | ||
9262 | return Ret_Result; | |
ee6ba406 | 9263 | end Selected_Range_Checks; |
9264 | ||
9265 | ------------------------------- | |
9266 | -- Storage_Checks_Suppressed -- | |
9267 | ------------------------------- | |
9268 | ||
9269 | function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is | |
9270 | begin | |
9dfe12ae | 9271 | if Present (E) and then Checks_May_Be_Suppressed (E) then |
9272 | return Is_Check_Suppressed (E, Storage_Check); | |
9273 | else | |
fafc6b97 | 9274 | return Scope_Suppress.Suppress (Storage_Check); |
9dfe12ae | 9275 | end if; |
ee6ba406 | 9276 | end Storage_Checks_Suppressed; |
9277 | ||
9278 | --------------------------- | |
9279 | -- Tag_Checks_Suppressed -- | |
9280 | --------------------------- | |
9281 | ||
9282 | function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is | |
9283 | begin | |
89f1e35c | 9284 | if Present (E) |
9285 | and then Checks_May_Be_Suppressed (E) | |
9286 | then | |
9287 | return Is_Check_Suppressed (E, Tag_Check); | |
9dfe12ae | 9288 | end if; |
9289 | ||
fafc6b97 | 9290 | return Scope_Suppress.Suppress (Tag_Check); |
ee6ba406 | 9291 | end Tag_Checks_Suppressed; |
9292 | ||
0577b0b1 | 9293 | -------------------------- |
9294 | -- Validity_Check_Range -- | |
9295 | -------------------------- | |
9296 | ||
9297 | procedure Validity_Check_Range (N : Node_Id) is | |
9298 | begin | |
9299 | if Validity_Checks_On and Validity_Check_Operands then | |
9300 | if Nkind (N) = N_Range then | |
9301 | Ensure_Valid (Low_Bound (N)); | |
9302 | Ensure_Valid (High_Bound (N)); | |
9303 | end if; | |
9304 | end if; | |
9305 | end Validity_Check_Range; | |
9306 | ||
9307 | -------------------------------- | |
9308 | -- Validity_Checks_Suppressed -- | |
9309 | -------------------------------- | |
9310 | ||
9311 | function Validity_Checks_Suppressed (E : Entity_Id) return Boolean is | |
9312 | begin | |
9313 | if Present (E) and then Checks_May_Be_Suppressed (E) then | |
9314 | return Is_Check_Suppressed (E, Validity_Check); | |
9315 | else | |
fafc6b97 | 9316 | return Scope_Suppress.Suppress (Validity_Check); |
0577b0b1 | 9317 | end if; |
9318 | end Validity_Checks_Suppressed; | |
9319 | ||
ee6ba406 | 9320 | end Checks; |