1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2011, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
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;
31 with Exp_Ch4; use Exp_Ch4;
32 with Exp_Ch11; use Exp_Ch11;
33 with Exp_Pakd; use Exp_Pakd;
34 with Exp_Util; use Exp_Util;
35 with Elists; use Elists;
36 with Eval_Fat; use Eval_Fat;
37 with Freeze; use Freeze;
39 with Nlists; use Nlists;
40 with Nmake; use Nmake;
42 with Output; use Output;
43 with Restrict; use Restrict;
44 with Rident; use Rident;
45 with Rtsfind; use Rtsfind;
47 with Sem_Aux; use Sem_Aux;
48 with Sem_Eval; use Sem_Eval;
49 with Sem_Ch3; use Sem_Ch3;
50 with Sem_Ch8; use Sem_Ch8;
51 with Sem_Res; use Sem_Res;
52 with Sem_Util; use Sem_Util;
53 with Sem_Warn; use Sem_Warn;
54 with Sinfo; use Sinfo;
55 with Sinput; use Sinput;
56 with Snames; use Snames;
57 with Sprint; use Sprint;
58 with Stand; use Stand;
59 with Targparm; use Targparm;
60 with Tbuild; use Tbuild;
61 with Ttypes; use Ttypes;
62 with Urealp; use Urealp;
63 with Validsw; use Validsw;
65 package body Checks is
67 -- General note: many of these routines are concerned with generating
68 -- checking code to make sure that constraint error is raised at runtime.
69 -- Clearly this code is only needed if the expander is active, since
70 -- otherwise we will not be generating code or going into the runtime
73 -- We therefore disconnect most of these checks if the expander is
74 -- inactive. This has the additional benefit that we do not need to
75 -- worry about the tree being messed up by previous errors (since errors
76 -- turn off expansion anyway).
78 -- There are a few exceptions to the above rule. For instance routines
79 -- such as Apply_Scalar_Range_Check that do not insert any code can be
80 -- safely called even when the Expander is inactive (but Errors_Detected
81 -- is 0). The benefit of executing this code when expansion is off, is
82 -- the ability to emit constraint error warning for static expressions
83 -- even when we are not generating code.
85 -------------------------------------
86 -- Suppression of Redundant Checks --
87 -------------------------------------
89 -- This unit implements a limited circuit for removal of redundant
90 -- checks. The processing is based on a tracing of simple sequential
91 -- flow. For any sequence of statements, we save expressions that are
92 -- marked to be checked, and then if the same expression appears later
93 -- with the same check, then under certain circumstances, the second
94 -- check can be suppressed.
96 -- Basically, we can suppress the check if we know for certain that
97 -- the previous expression has been elaborated (together with its
98 -- check), and we know that the exception frame is the same, and that
99 -- nothing has happened to change the result of the exception.
101 -- Let us examine each of these three conditions in turn to describe
102 -- how we ensure that this condition is met.
104 -- First, we need to know for certain that the previous expression has
105 -- been executed. This is done principally by the mechanism of calling
106 -- Conditional_Statements_Begin at the start of any statement sequence
107 -- and Conditional_Statements_End at the end. The End call causes all
108 -- checks remembered since the Begin call to be discarded. This does
109 -- miss a few cases, notably the case of a nested BEGIN-END block with
110 -- no exception handlers. But the important thing is to be conservative.
111 -- The other protection is that all checks are discarded if a label
112 -- is encountered, since then the assumption of sequential execution
113 -- is violated, and we don't know enough about the flow.
115 -- Second, we need to know that the exception frame is the same. We
116 -- do this by killing all remembered checks when we enter a new frame.
117 -- Again, that's over-conservative, but generally the cases we can help
118 -- with are pretty local anyway (like the body of a loop for example).
120 -- Third, we must be sure to forget any checks which are no longer valid.
121 -- This is done by two mechanisms, first the Kill_Checks_Variable call is
122 -- used to note any changes to local variables. We only attempt to deal
123 -- with checks involving local variables, so we do not need to worry
124 -- about global variables. Second, a call to any non-global procedure
125 -- causes us to abandon all stored checks, since such a all may affect
126 -- the values of any local variables.
128 -- The following define the data structures used to deal with remembering
129 -- checks so that redundant checks can be eliminated as described above.
131 -- Right now, the only expressions that we deal with are of the form of
132 -- simple local objects (either declared locally, or IN parameters) or
133 -- such objects plus/minus a compile time known constant. We can do
134 -- more later on if it seems worthwhile, but this catches many simple
135 -- cases in practice.
137 -- The following record type reflects a single saved check. An entry
138 -- is made in the stack of saved checks if and only if the expression
139 -- has been elaborated with the indicated checks.
141 type Saved_Check is record
143 -- Set True if entry is killed by Kill_Checks
146 -- The entity involved in the expression that is checked
149 -- A compile time value indicating the result of adding or
150 -- subtracting a compile time value. This value is to be
151 -- added to the value of the Entity. A value of zero is
152 -- used for the case of a simple entity reference.
154 Check_Type : Character;
155 -- This is set to 'R' for a range check (in which case Target_Type
156 -- is set to the target type for the range check) or to 'O' for an
157 -- overflow check (in which case Target_Type is set to Empty).
159 Target_Type : Entity_Id;
160 -- Used only if Do_Range_Check is set. Records the target type for
161 -- the check. We need this, because a check is a duplicate only if
162 -- it has the same target type (or more accurately one with a
163 -- range that is smaller or equal to the stored target type of a
167 -- The following table keeps track of saved checks. Rather than use an
168 -- extensible table. We just use a table of fixed size, and we discard
169 -- any saved checks that do not fit. That's very unlikely to happen and
170 -- this is only an optimization in any case.
172 Saved_Checks : array (Int range 1 .. 200) of Saved_Check;
173 -- Array of saved checks
175 Num_Saved_Checks : Nat := 0;
176 -- Number of saved checks
178 -- The following stack keeps track of statement ranges. It is treated
179 -- as a stack. When Conditional_Statements_Begin is called, an entry
180 -- is pushed onto this stack containing the value of Num_Saved_Checks
181 -- at the time of the call. Then when Conditional_Statements_End is
182 -- called, this value is popped off and used to reset Num_Saved_Checks.
184 -- Note: again, this is a fixed length stack with a size that should
185 -- always be fine. If the value of the stack pointer goes above the
186 -- limit, then we just forget all saved checks.
188 Saved_Checks_Stack : array (Int range 1 .. 100) of Nat;
189 Saved_Checks_TOS : Nat := 0;
191 -----------------------
192 -- Local Subprograms --
193 -----------------------
195 procedure Apply_Float_Conversion_Check
197 Target_Typ : Entity_Id);
198 -- The checks on a conversion from a floating-point type to an integer
199 -- type are delicate. They have to be performed before conversion, they
200 -- have to raise an exception when the operand is a NaN, and rounding must
201 -- be taken into account to determine the safe bounds of the operand.
203 procedure Apply_Selected_Length_Checks
205 Target_Typ : Entity_Id;
206 Source_Typ : Entity_Id;
207 Do_Static : Boolean);
208 -- This is the subprogram that does all the work for Apply_Length_Check
209 -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as
210 -- described for the above routines. The Do_Static flag indicates that
211 -- only a static check is to be done.
213 procedure Apply_Selected_Range_Checks
215 Target_Typ : Entity_Id;
216 Source_Typ : Entity_Id;
217 Do_Static : Boolean);
218 -- This is the subprogram that does all the work for Apply_Range_Check.
219 -- Expr, Target_Typ and Source_Typ are as described for the above
220 -- routine. The Do_Static flag indicates that only a static check is
223 type Check_Type is new Check_Id range Access_Check .. Division_Check;
224 function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean;
225 -- This function is used to see if an access or division by zero check is
226 -- needed. The check is to be applied to a single variable appearing in the
227 -- source, and N is the node for the reference. If N is not of this form,
228 -- True is returned with no further processing. If N is of the right form,
229 -- then further processing determines if the given Check is needed.
231 -- The particular circuit is to see if we have the case of a check that is
232 -- not needed because it appears in the right operand of a short circuited
233 -- conditional where the left operand guards the check. For example:
235 -- if Var = 0 or else Q / Var > 12 then
239 -- In this example, the division check is not required. At the same time
240 -- we can issue warnings for suspicious use of non-short-circuited forms,
243 -- if Var = 0 or Q / Var > 12 then
249 Check_Type : Character;
250 Target_Type : Entity_Id;
251 Entry_OK : out Boolean;
255 -- This routine is used by Enable_Range_Check and Enable_Overflow_Check
256 -- to see if a check is of the form for optimization, and if so, to see
257 -- if it has already been performed. Expr is the expression to check,
258 -- and Check_Type is 'R' for a range check, 'O' for an overflow check.
259 -- Target_Type is the target type for a range check, and Empty for an
260 -- overflow check. If the entry is not of the form for optimization,
261 -- then Entry_OK is set to False, and the remaining out parameters
262 -- are undefined. If the entry is OK, then Ent/Ofs are set to the
263 -- entity and offset from the expression. Check_Num is the number of
264 -- a matching saved entry in Saved_Checks, or zero if no such entry
267 function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id;
268 -- If a discriminal is used in constraining a prival, Return reference
269 -- to the discriminal of the protected body (which renames the parameter
270 -- of the enclosing protected operation). This clumsy transformation is
271 -- needed because privals are created too late and their actual subtypes
272 -- are not available when analysing the bodies of the protected operations.
273 -- This function is called whenever the bound is an entity and the scope
274 -- indicates a protected operation. If the bound is an in-parameter of
275 -- a protected operation that is not a prival, the function returns the
277 -- To be cleaned up???
279 function Guard_Access
282 Ck_Node : Node_Id) return Node_Id;
283 -- In the access type case, guard the test with a test to ensure
284 -- that the access value is non-null, since the checks do not
285 -- not apply to null access values.
287 procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr);
288 -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the
289 -- Constraint_Error node.
291 function Range_Or_Validity_Checks_Suppressed
292 (Expr : Node_Id) return Boolean;
293 -- Returns True if either range or validity checks or both are suppressed
294 -- for the type of the given expression, or, if the expression is the name
295 -- of an entity, if these checks are suppressed for the entity.
297 function Selected_Length_Checks
299 Target_Typ : Entity_Id;
300 Source_Typ : Entity_Id;
301 Warn_Node : Node_Id) return Check_Result;
302 -- Like Apply_Selected_Length_Checks, except it doesn't modify
303 -- anything, just returns a list of nodes as described in the spec of
304 -- this package for the Range_Check function.
306 function Selected_Range_Checks
308 Target_Typ : Entity_Id;
309 Source_Typ : Entity_Id;
310 Warn_Node : Node_Id) return Check_Result;
311 -- Like Apply_Selected_Range_Checks, except it doesn't modify anything,
312 -- just returns a list of nodes as described in the spec of this package
313 -- for the Range_Check function.
315 ------------------------------
316 -- Access_Checks_Suppressed --
317 ------------------------------
319 function Access_Checks_Suppressed (E : Entity_Id) return Boolean is
321 if Present (E) and then Checks_May_Be_Suppressed (E) then
322 return Is_Check_Suppressed (E, Access_Check);
324 return Scope_Suppress (Access_Check);
326 end Access_Checks_Suppressed;
328 -------------------------------------
329 -- Accessibility_Checks_Suppressed --
330 -------------------------------------
332 function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is
334 if Present (E) and then Checks_May_Be_Suppressed (E) then
335 return Is_Check_Suppressed (E, Accessibility_Check);
337 return Scope_Suppress (Accessibility_Check);
339 end Accessibility_Checks_Suppressed;
341 -----------------------------
342 -- Activate_Division_Check --
343 -----------------------------
345 procedure Activate_Division_Check (N : Node_Id) is
347 Set_Do_Division_Check (N, True);
348 Possible_Local_Raise (N, Standard_Constraint_Error);
349 end Activate_Division_Check;
351 -----------------------------
352 -- Activate_Overflow_Check --
353 -----------------------------
355 procedure Activate_Overflow_Check (N : Node_Id) is
357 Set_Do_Overflow_Check (N, True);
358 Possible_Local_Raise (N, Standard_Constraint_Error);
359 end Activate_Overflow_Check;
361 --------------------------
362 -- Activate_Range_Check --
363 --------------------------
365 procedure Activate_Range_Check (N : Node_Id) is
367 Set_Do_Range_Check (N, True);
368 Possible_Local_Raise (N, Standard_Constraint_Error);
369 end Activate_Range_Check;
371 ---------------------------------
372 -- Alignment_Checks_Suppressed --
373 ---------------------------------
375 function Alignment_Checks_Suppressed (E : Entity_Id) return Boolean is
377 if Present (E) and then Checks_May_Be_Suppressed (E) then
378 return Is_Check_Suppressed (E, Alignment_Check);
380 return Scope_Suppress (Alignment_Check);
382 end Alignment_Checks_Suppressed;
384 -------------------------
385 -- Append_Range_Checks --
386 -------------------------
388 procedure Append_Range_Checks
389 (Checks : Check_Result;
391 Suppress_Typ : Entity_Id;
392 Static_Sloc : Source_Ptr;
395 Internal_Flag_Node : constant Node_Id := Flag_Node;
396 Internal_Static_Sloc : constant Source_Ptr := Static_Sloc;
398 Checks_On : constant Boolean :=
399 (not Index_Checks_Suppressed (Suppress_Typ))
401 (not Range_Checks_Suppressed (Suppress_Typ));
404 -- For now we just return if Checks_On is false, however this should
405 -- be enhanced to check for an always True value in the condition
406 -- and to generate a compilation warning???
408 if not Checks_On then
413 exit when No (Checks (J));
415 if Nkind (Checks (J)) = N_Raise_Constraint_Error
416 and then Present (Condition (Checks (J)))
418 if not Has_Dynamic_Range_Check (Internal_Flag_Node) then
419 Append_To (Stmts, Checks (J));
420 Set_Has_Dynamic_Range_Check (Internal_Flag_Node);
426 Make_Raise_Constraint_Error (Internal_Static_Sloc,
427 Reason => CE_Range_Check_Failed));
430 end Append_Range_Checks;
432 ------------------------
433 -- Apply_Access_Check --
434 ------------------------
436 procedure Apply_Access_Check (N : Node_Id) is
437 P : constant Node_Id := Prefix (N);
440 -- We do not need checks if we are not generating code (i.e. the
441 -- expander is not active). This is not just an optimization, there
442 -- are cases (e.g. with pragma Debug) where generating the checks
443 -- can cause real trouble).
445 if not Expander_Active then
449 -- No check if short circuiting makes check unnecessary
451 if not Check_Needed (P, Access_Check) then
455 -- No check if accessing the Offset_To_Top component of a dispatch
456 -- table. They are safe by construction.
458 if Tagged_Type_Expansion
459 and then Present (Etype (P))
460 and then RTU_Loaded (Ada_Tags)
461 and then RTE_Available (RE_Offset_To_Top_Ptr)
462 and then Etype (P) = RTE (RE_Offset_To_Top_Ptr)
467 -- Otherwise go ahead and install the check
469 Install_Null_Excluding_Check (P);
470 end Apply_Access_Check;
472 -------------------------------
473 -- Apply_Accessibility_Check --
474 -------------------------------
476 procedure Apply_Accessibility_Check
479 Insert_Node : Node_Id)
481 Loc : constant Source_Ptr := Sloc (N);
482 Param_Ent : constant Entity_Id := Param_Entity (N);
483 Param_Level : Node_Id;
484 Type_Level : Node_Id;
487 if Inside_A_Generic then
490 -- Only apply the run-time check if the access parameter has an
491 -- associated extra access level parameter and when the level of the
492 -- type is less deep than the level of the access parameter, and
493 -- accessibility checks are not suppressed.
495 elsif Present (Param_Ent)
496 and then Present (Extra_Accessibility (Param_Ent))
497 and then UI_Gt (Object_Access_Level (N), Type_Access_Level (Typ))
498 and then not Accessibility_Checks_Suppressed (Param_Ent)
499 and then not Accessibility_Checks_Suppressed (Typ)
502 New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc);
505 Make_Integer_Literal (Loc, Type_Access_Level (Typ));
507 -- Raise Program_Error if the accessibility level of the access
508 -- parameter is deeper than the level of the target access type.
510 Insert_Action (Insert_Node,
511 Make_Raise_Program_Error (Loc,
514 Left_Opnd => Param_Level,
515 Right_Opnd => Type_Level),
516 Reason => PE_Accessibility_Check_Failed));
518 Analyze_And_Resolve (N);
520 end Apply_Accessibility_Check;
522 --------------------------------
523 -- Apply_Address_Clause_Check --
524 --------------------------------
526 procedure Apply_Address_Clause_Check (E : Entity_Id; N : Node_Id) is
527 AC : constant Node_Id := Address_Clause (E);
528 Loc : constant Source_Ptr := Sloc (AC);
529 Typ : constant Entity_Id := Etype (E);
530 Aexp : constant Node_Id := Expression (AC);
533 -- Address expression (not necessarily the same as Aexp, for example
534 -- when Aexp is a reference to a constant, in which case Expr gets
535 -- reset to reference the value expression of the constant.
537 procedure Compile_Time_Bad_Alignment;
538 -- Post error warnings when alignment is known to be incompatible. Note
539 -- that we do not go as far as inserting a raise of Program_Error since
540 -- this is an erroneous case, and it may happen that we are lucky and an
541 -- underaligned address turns out to be OK after all.
543 --------------------------------
544 -- Compile_Time_Bad_Alignment --
545 --------------------------------
547 procedure Compile_Time_Bad_Alignment is
549 if Address_Clause_Overlay_Warnings then
551 ("?specified address for& may be inconsistent with alignment ",
554 ("\?program execution may be erroneous (RM 13.3(27))",
556 Set_Address_Warning_Posted (AC);
558 end Compile_Time_Bad_Alignment;
560 -- Start of processing for Apply_Address_Clause_Check
563 -- See if alignment check needed. Note that we never need a check if the
564 -- maximum alignment is one, since the check will always succeed.
566 -- Note: we do not check for checks suppressed here, since that check
567 -- was done in Sem_Ch13 when the address clause was processed. We are
568 -- only called if checks were not suppressed. The reason for this is
569 -- that we have to delay the call to Apply_Alignment_Check till freeze
570 -- time (so that all types etc are elaborated), but we have to check
571 -- the status of check suppressing at the point of the address clause.
574 or else not Check_Address_Alignment (AC)
575 or else Maximum_Alignment = 1
580 -- Obtain expression from address clause
582 Expr := Expression (AC);
584 -- The following loop digs for the real expression to use in the check
587 -- For constant, get constant expression
589 if Is_Entity_Name (Expr)
590 and then Ekind (Entity (Expr)) = E_Constant
592 Expr := Constant_Value (Entity (Expr));
594 -- For unchecked conversion, get result to convert
596 elsif Nkind (Expr) = N_Unchecked_Type_Conversion then
597 Expr := Expression (Expr);
599 -- For (common case) of To_Address call, get argument
601 elsif Nkind (Expr) = N_Function_Call
602 and then Is_Entity_Name (Name (Expr))
603 and then Is_RTE (Entity (Name (Expr)), RE_To_Address)
605 Expr := First (Parameter_Associations (Expr));
607 if Nkind (Expr) = N_Parameter_Association then
608 Expr := Explicit_Actual_Parameter (Expr);
611 -- We finally have the real expression
618 -- See if we know that Expr has a bad alignment at compile time
620 if Compile_Time_Known_Value (Expr)
621 and then (Known_Alignment (E) or else Known_Alignment (Typ))
624 AL : Uint := Alignment (Typ);
627 -- The object alignment might be more restrictive than the
630 if Known_Alignment (E) then
634 if Expr_Value (Expr) mod AL /= 0 then
635 Compile_Time_Bad_Alignment;
641 -- If the expression has the form X'Address, then we can find out if
642 -- the object X has an alignment that is compatible with the object E.
643 -- If it hasn't or we don't know, we defer issuing the warning until
644 -- the end of the compilation to take into account back end annotations.
646 elsif Nkind (Expr) = N_Attribute_Reference
647 and then Attribute_Name (Expr) = Name_Address
648 and then Has_Compatible_Alignment (E, Prefix (Expr)) = Known_Compatible
653 -- Here we do not know if the value is acceptable. Strictly we don't
654 -- have to do anything, since if the alignment is bad, we have an
655 -- erroneous program. However we are allowed to check for erroneous
656 -- conditions and we decide to do this by default if the check is not
659 -- However, don't do the check if elaboration code is unwanted
661 if Restriction_Active (No_Elaboration_Code) then
664 -- Generate a check to raise PE if alignment may be inappropriate
667 -- If the original expression is a non-static constant, use the
668 -- name of the constant itself rather than duplicating its
669 -- defining expression, which was extracted above.
671 -- Note: Expr is empty if the address-clause is applied to in-mode
672 -- actuals (allowed by 13.1(22)).
674 if not Present (Expr)
676 (Is_Entity_Name (Expression (AC))
677 and then Ekind (Entity (Expression (AC))) = E_Constant
678 and then Nkind (Parent (Entity (Expression (AC))))
679 = N_Object_Declaration)
681 Expr := New_Copy_Tree (Expression (AC));
683 Remove_Side_Effects (Expr);
686 Insert_After_And_Analyze (N,
687 Make_Raise_Program_Error (Loc,
694 (RTE (RE_Integer_Address), Expr),
696 Make_Attribute_Reference (Loc,
697 Prefix => New_Occurrence_Of (E, Loc),
698 Attribute_Name => Name_Alignment)),
699 Right_Opnd => Make_Integer_Literal (Loc, Uint_0)),
700 Reason => PE_Misaligned_Address_Value),
701 Suppress => All_Checks);
706 -- If we have some missing run time component in configurable run time
707 -- mode then just skip the check (it is not required in any case).
709 when RE_Not_Available =>
711 end Apply_Address_Clause_Check;
713 -------------------------------------
714 -- Apply_Arithmetic_Overflow_Check --
715 -------------------------------------
717 -- This routine is called only if the type is an integer type, and a
718 -- software arithmetic overflow check may be needed for op (add, subtract,
719 -- or multiply). This check is performed only if Software_Overflow_Checking
720 -- is enabled and Do_Overflow_Check is set. In this case we expand the
721 -- operation into a more complex sequence of tests that ensures that
722 -- overflow is properly caught.
724 procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is
725 Loc : constant Source_Ptr := Sloc (N);
726 Typ : constant Entity_Id := Etype (N);
727 Rtyp : constant Entity_Id := Root_Type (Typ);
730 -- An interesting special case. If the arithmetic operation appears as
731 -- the operand of a type conversion:
735 -- and all the following conditions apply:
737 -- arithmetic operation is for a signed integer type
738 -- target type type1 is a static integer subtype
739 -- range of x and y are both included in the range of type1
740 -- range of x op y is included in the range of type1
741 -- size of type1 is at least twice the result size of op
743 -- then we don't do an overflow check in any case, instead we transform
744 -- the operation so that we end up with:
746 -- type1 (type1 (x) op type1 (y))
748 -- This avoids intermediate overflow before the conversion. It is
749 -- explicitly permitted by RM 3.5.4(24):
751 -- For the execution of a predefined operation of a signed integer
752 -- type, the implementation need not raise Constraint_Error if the
753 -- result is outside the base range of the type, so long as the
754 -- correct result is produced.
756 -- It's hard to imagine that any programmer counts on the exception
757 -- being raised in this case, and in any case it's wrong coding to
758 -- have this expectation, given the RM permission. Furthermore, other
759 -- Ada compilers do allow such out of range results.
761 -- Note that we do this transformation even if overflow checking is
762 -- off, since this is precisely about giving the "right" result and
763 -- avoiding the need for an overflow check.
765 -- Note: this circuit is partially redundant with respect to the similar
766 -- processing in Exp_Ch4.Expand_N_Type_Conversion, but the latter deals
767 -- with cases that do not come through here. We still need the following
768 -- processing even with the Exp_Ch4 code in place, since we want to be
769 -- sure not to generate the arithmetic overflow check in these cases
770 -- (Exp_Ch4 would have a hard time removing them once generated).
772 if Is_Signed_Integer_Type (Typ)
773 and then Nkind (Parent (N)) = N_Type_Conversion
776 Target_Type : constant Entity_Id :=
777 Base_Type (Entity (Subtype_Mark (Parent (N))));
791 if Is_Integer_Type (Target_Type)
792 and then RM_Size (Root_Type (Target_Type)) >= 2 * RM_Size (Rtyp)
794 Tlo := Expr_Value (Type_Low_Bound (Target_Type));
795 Thi := Expr_Value (Type_High_Bound (Target_Type));
798 (Left_Opnd (N), LOK, Llo, Lhi, Assume_Valid => True);
800 (Right_Opnd (N), ROK, Rlo, Rhi, Assume_Valid => True);
803 and then Tlo <= Llo and then Lhi <= Thi
804 and then Tlo <= Rlo and then Rhi <= Thi
806 Determine_Range (N, VOK, Vlo, Vhi, Assume_Valid => True);
808 if VOK and then Tlo <= Vlo and then Vhi <= Thi then
809 Rewrite (Left_Opnd (N),
810 Make_Type_Conversion (Loc,
811 Subtype_Mark => New_Occurrence_Of (Target_Type, Loc),
812 Expression => Relocate_Node (Left_Opnd (N))));
814 Rewrite (Right_Opnd (N),
815 Make_Type_Conversion (Loc,
816 Subtype_Mark => New_Occurrence_Of (Target_Type, Loc),
817 Expression => Relocate_Node (Right_Opnd (N))));
819 -- Rewrite the conversion operand so that the original
820 -- node is retained, in order to avoid the warning for
821 -- redundant conversions in Resolve_Type_Conversion.
823 Rewrite (N, Relocate_Node (N));
825 Set_Etype (N, Target_Type);
827 Analyze_And_Resolve (Left_Opnd (N), Target_Type);
828 Analyze_And_Resolve (Right_Opnd (N), Target_Type);
830 -- Given that the target type is twice the size of the
831 -- source type, overflow is now impossible, so we can
832 -- safely kill the overflow check and return.
834 Set_Do_Overflow_Check (N, False);
842 -- Now see if an overflow check is required
845 Siz : constant Int := UI_To_Int (Esize (Rtyp));
846 Dsiz : constant Int := Siz * 2;
853 -- Skip check if back end does overflow checks, or the overflow flag
854 -- is not set anyway, or we are not doing code expansion, or the
855 -- parent node is a type conversion whose operand is an arithmetic
856 -- operation on signed integers on which the expander can promote
857 -- later the operands to type Integer (see Expand_N_Type_Conversion).
859 -- Special case CLI target, where arithmetic overflow checks can be
860 -- performed for integer and long_integer
862 if Backend_Overflow_Checks_On_Target
863 or else not Do_Overflow_Check (N)
864 or else not Expander_Active
865 or else (Present (Parent (N))
866 and then Nkind (Parent (N)) = N_Type_Conversion
867 and then Integer_Promotion_Possible (Parent (N)))
869 (VM_Target = CLI_Target and then Siz >= Standard_Integer_Size)
874 -- Otherwise, generate the full general code for front end overflow
875 -- detection, which works by doing arithmetic in a larger type:
881 -- Typ (Checktyp (x) op Checktyp (y));
883 -- where Typ is the type of the original expression, and Checktyp is
884 -- an integer type of sufficient length to hold the largest possible
887 -- If the size of check type exceeds the size of Long_Long_Integer,
888 -- we use a different approach, expanding to:
890 -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y)))
892 -- where xxx is Add, Multiply or Subtract as appropriate
894 -- Find check type if one exists
896 if Dsiz <= Standard_Integer_Size then
897 Ctyp := Standard_Integer;
899 elsif Dsiz <= Standard_Long_Long_Integer_Size then
900 Ctyp := Standard_Long_Long_Integer;
902 -- No check type exists, use runtime call
905 if Nkind (N) = N_Op_Add then
906 Cent := RE_Add_With_Ovflo_Check;
908 elsif Nkind (N) = N_Op_Multiply then
909 Cent := RE_Multiply_With_Ovflo_Check;
912 pragma Assert (Nkind (N) = N_Op_Subtract);
913 Cent := RE_Subtract_With_Ovflo_Check;
918 Make_Function_Call (Loc,
919 Name => New_Reference_To (RTE (Cent), Loc),
920 Parameter_Associations => New_List (
921 OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)),
922 OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N))))));
924 Analyze_And_Resolve (N, Typ);
928 -- If we fall through, we have the case where we do the arithmetic
929 -- in the next higher type and get the check by conversion. In these
930 -- cases Ctyp is set to the type to be used as the check type.
932 Opnod := Relocate_Node (N);
934 Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod));
937 Set_Etype (Opnd, Ctyp);
938 Set_Analyzed (Opnd, True);
939 Set_Left_Opnd (Opnod, Opnd);
941 Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod));
944 Set_Etype (Opnd, Ctyp);
945 Set_Analyzed (Opnd, True);
946 Set_Right_Opnd (Opnod, Opnd);
948 -- The type of the operation changes to the base type of the check
949 -- type, and we reset the overflow check indication, since clearly no
950 -- overflow is possible now that we are using a double length type.
951 -- We also set the Analyzed flag to avoid a recursive attempt to
954 Set_Etype (Opnod, Base_Type (Ctyp));
955 Set_Do_Overflow_Check (Opnod, False);
956 Set_Analyzed (Opnod, True);
958 -- Now build the outer conversion
960 Opnd := OK_Convert_To (Typ, Opnod);
962 Set_Etype (Opnd, Typ);
964 -- In the discrete type case, we directly generate the range check
965 -- for the outer operand. This range check will implement the
966 -- required overflow check.
968 if Is_Discrete_Type (Typ) then
971 (Expression (N), Typ, CE_Overflow_Check_Failed);
973 -- For other types, we enable overflow checking on the conversion,
974 -- after setting the node as analyzed to prevent recursive attempts
975 -- to expand the conversion node.
978 Set_Analyzed (Opnd, True);
979 Enable_Overflow_Check (Opnd);
984 when RE_Not_Available =>
987 end Apply_Arithmetic_Overflow_Check;
989 ----------------------------
990 -- Apply_Constraint_Check --
991 ----------------------------
993 procedure Apply_Constraint_Check
996 No_Sliding : Boolean := False)
998 Desig_Typ : Entity_Id;
1001 -- No checks inside a generic (check the instantiations)
1003 if Inside_A_Generic then
1007 -- Apply required constraint checks
1009 if Is_Scalar_Type (Typ) then
1010 Apply_Scalar_Range_Check (N, Typ);
1012 elsif Is_Array_Type (Typ) then
1014 -- A useful optimization: an aggregate with only an others clause
1015 -- always has the right bounds.
1017 if Nkind (N) = N_Aggregate
1018 and then No (Expressions (N))
1020 (First (Choices (First (Component_Associations (N)))))
1026 if Is_Constrained (Typ) then
1027 Apply_Length_Check (N, Typ);
1030 Apply_Range_Check (N, Typ);
1033 Apply_Range_Check (N, Typ);
1036 elsif (Is_Record_Type (Typ)
1037 or else Is_Private_Type (Typ))
1038 and then Has_Discriminants (Base_Type (Typ))
1039 and then Is_Constrained (Typ)
1041 Apply_Discriminant_Check (N, Typ);
1043 elsif Is_Access_Type (Typ) then
1045 Desig_Typ := Designated_Type (Typ);
1047 -- No checks necessary if expression statically null
1049 if Known_Null (N) then
1050 if Can_Never_Be_Null (Typ) then
1051 Install_Null_Excluding_Check (N);
1054 -- No sliding possible on access to arrays
1056 elsif Is_Array_Type (Desig_Typ) then
1057 if Is_Constrained (Desig_Typ) then
1058 Apply_Length_Check (N, Typ);
1061 Apply_Range_Check (N, Typ);
1063 elsif Has_Discriminants (Base_Type (Desig_Typ))
1064 and then Is_Constrained (Desig_Typ)
1066 Apply_Discriminant_Check (N, Typ);
1069 -- Apply the 2005 Null_Excluding check. Note that we do not apply
1070 -- this check if the constraint node is illegal, as shown by having
1071 -- an error posted. This additional guard prevents cascaded errors
1072 -- and compiler aborts on illegal programs involving Ada 2005 checks.
1074 if Can_Never_Be_Null (Typ)
1075 and then not Can_Never_Be_Null (Etype (N))
1076 and then not Error_Posted (N)
1078 Install_Null_Excluding_Check (N);
1081 end Apply_Constraint_Check;
1083 ------------------------------
1084 -- Apply_Discriminant_Check --
1085 ------------------------------
1087 procedure Apply_Discriminant_Check
1090 Lhs : Node_Id := Empty)
1092 Loc : constant Source_Ptr := Sloc (N);
1093 Do_Access : constant Boolean := Is_Access_Type (Typ);
1094 S_Typ : Entity_Id := Etype (N);
1098 function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean;
1099 -- A heap object with an indefinite subtype is constrained by its
1100 -- initial value, and assigning to it requires a constraint_check.
1101 -- The target may be an explicit dereference, or a renaming of one.
1103 function Is_Aliased_Unconstrained_Component return Boolean;
1104 -- It is possible for an aliased component to have a nominal
1105 -- unconstrained subtype (through instantiation). If this is a
1106 -- discriminated component assigned in the expansion of an aggregate
1107 -- in an initialization, the check must be suppressed. This unusual
1108 -- situation requires a predicate of its own.
1110 ----------------------------------
1111 -- Denotes_Explicit_Dereference --
1112 ----------------------------------
1114 function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean is
1117 Nkind (Obj) = N_Explicit_Dereference
1119 (Is_Entity_Name (Obj)
1120 and then Present (Renamed_Object (Entity (Obj)))
1121 and then Nkind (Renamed_Object (Entity (Obj))) =
1122 N_Explicit_Dereference);
1123 end Denotes_Explicit_Dereference;
1125 ----------------------------------------
1126 -- Is_Aliased_Unconstrained_Component --
1127 ----------------------------------------
1129 function Is_Aliased_Unconstrained_Component return Boolean is
1134 if Nkind (Lhs) /= N_Selected_Component then
1137 Comp := Entity (Selector_Name (Lhs));
1138 Pref := Prefix (Lhs);
1141 if Ekind (Comp) /= E_Component
1142 or else not Is_Aliased (Comp)
1147 return not Comes_From_Source (Pref)
1148 and then In_Instance
1149 and then not Is_Constrained (Etype (Comp));
1150 end Is_Aliased_Unconstrained_Component;
1152 -- Start of processing for Apply_Discriminant_Check
1156 T_Typ := Designated_Type (Typ);
1161 -- Nothing to do if discriminant checks are suppressed or else no code
1162 -- is to be generated
1164 if not Expander_Active
1165 or else Discriminant_Checks_Suppressed (T_Typ)
1170 -- No discriminant checks necessary for an access when expression is
1171 -- statically Null. This is not only an optimization, it is fundamental
1172 -- because otherwise discriminant checks may be generated in init procs
1173 -- for types containing an access to a not-yet-frozen record, causing a
1174 -- deadly forward reference.
1176 -- Also, if the expression is of an access type whose designated type is
1177 -- incomplete, then the access value must be null and we suppress the
1180 if Known_Null (N) then
1183 elsif Is_Access_Type (S_Typ) then
1184 S_Typ := Designated_Type (S_Typ);
1186 if Ekind (S_Typ) = E_Incomplete_Type then
1191 -- If an assignment target is present, then we need to generate the
1192 -- actual subtype if the target is a parameter or aliased object with
1193 -- an unconstrained nominal subtype.
1195 -- Ada 2005 (AI-363): For Ada 2005, we limit the building of the actual
1196 -- subtype to the parameter and dereference cases, since other aliased
1197 -- objects are unconstrained (unless the nominal subtype is explicitly
1201 and then (Present (Param_Entity (Lhs))
1202 or else (Ada_Version < Ada_2005
1203 and then not Is_Constrained (T_Typ)
1204 and then Is_Aliased_View (Lhs)
1205 and then not Is_Aliased_Unconstrained_Component)
1206 or else (Ada_Version >= Ada_2005
1207 and then not Is_Constrained (T_Typ)
1208 and then Denotes_Explicit_Dereference (Lhs)
1209 and then Nkind (Original_Node (Lhs)) /=
1212 T_Typ := Get_Actual_Subtype (Lhs);
1215 -- Nothing to do if the type is unconstrained (this is the case where
1216 -- the actual subtype in the RM sense of N is unconstrained and no check
1219 if not Is_Constrained (T_Typ) then
1222 -- Ada 2005: nothing to do if the type is one for which there is a
1223 -- partial view that is constrained.
1225 elsif Ada_Version >= Ada_2005
1226 and then Has_Constrained_Partial_View (Base_Type (T_Typ))
1231 -- Nothing to do if the type is an Unchecked_Union
1233 if Is_Unchecked_Union (Base_Type (T_Typ)) then
1237 -- Suppress checks if the subtypes are the same. the check must be
1238 -- preserved in an assignment to a formal, because the constraint is
1239 -- given by the actual.
1241 if Nkind (Original_Node (N)) /= N_Allocator
1243 or else not Is_Entity_Name (Lhs)
1244 or else No (Param_Entity (Lhs)))
1247 or else (Do_Access and then Designated_Type (Typ) = S_Typ))
1248 and then not Is_Aliased_View (Lhs)
1253 -- We can also eliminate checks on allocators with a subtype mark that
1254 -- coincides with the context type. The context type may be a subtype
1255 -- without a constraint (common case, a generic actual).
1257 elsif Nkind (Original_Node (N)) = N_Allocator
1258 and then Is_Entity_Name (Expression (Original_Node (N)))
1261 Alloc_Typ : constant Entity_Id :=
1262 Entity (Expression (Original_Node (N)));
1265 if Alloc_Typ = T_Typ
1266 or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration
1267 and then Is_Entity_Name (
1268 Subtype_Indication (Parent (T_Typ)))
1269 and then Alloc_Typ = Base_Type (T_Typ))
1277 -- See if we have a case where the types are both constrained, and all
1278 -- the constraints are constants. In this case, we can do the check
1279 -- successfully at compile time.
1281 -- We skip this check for the case where the node is a rewritten`
1282 -- allocator, because it already carries the context subtype, and
1283 -- extracting the discriminants from the aggregate is messy.
1285 if Is_Constrained (S_Typ)
1286 and then Nkind (Original_Node (N)) /= N_Allocator
1296 -- S_Typ may not have discriminants in the case where it is a
1297 -- private type completed by a default discriminated type. In that
1298 -- case, we need to get the constraints from the underlying_type.
1299 -- If the underlying type is unconstrained (i.e. has no default
1300 -- discriminants) no check is needed.
1302 if Has_Discriminants (S_Typ) then
1303 Discr := First_Discriminant (S_Typ);
1304 DconS := First_Elmt (Discriminant_Constraint (S_Typ));
1307 Discr := First_Discriminant (Underlying_Type (S_Typ));
1310 (Discriminant_Constraint (Underlying_Type (S_Typ)));
1316 -- A further optimization: if T_Typ is derived from S_Typ
1317 -- without imposing a constraint, no check is needed.
1319 if Nkind (Original_Node (Parent (T_Typ))) =
1320 N_Full_Type_Declaration
1323 Type_Def : constant Node_Id :=
1325 (Original_Node (Parent (T_Typ)));
1327 if Nkind (Type_Def) = N_Derived_Type_Definition
1328 and then Is_Entity_Name (Subtype_Indication (Type_Def))
1329 and then Entity (Subtype_Indication (Type_Def)) = S_Typ
1337 DconT := First_Elmt (Discriminant_Constraint (T_Typ));
1339 while Present (Discr) loop
1340 ItemS := Node (DconS);
1341 ItemT := Node (DconT);
1343 -- For a discriminated component type constrained by the
1344 -- current instance of an enclosing type, there is no
1345 -- applicable discriminant check.
1347 if Nkind (ItemT) = N_Attribute_Reference
1348 and then Is_Access_Type (Etype (ItemT))
1349 and then Is_Entity_Name (Prefix (ItemT))
1350 and then Is_Type (Entity (Prefix (ItemT)))
1355 -- If the expressions for the discriminants are identical
1356 -- and it is side-effect free (for now just an entity),
1357 -- this may be a shared constraint, e.g. from a subtype
1358 -- without a constraint introduced as a generic actual.
1359 -- Examine other discriminants if any.
1362 and then Is_Entity_Name (ItemS)
1366 elsif not Is_OK_Static_Expression (ItemS)
1367 or else not Is_OK_Static_Expression (ItemT)
1371 elsif Expr_Value (ItemS) /= Expr_Value (ItemT) then
1372 if Do_Access then -- needs run-time check.
1375 Apply_Compile_Time_Constraint_Error
1376 (N, "incorrect value for discriminant&?",
1377 CE_Discriminant_Check_Failed, Ent => Discr);
1384 Next_Discriminant (Discr);
1393 -- Here we need a discriminant check. First build the expression
1394 -- for the comparisons of the discriminants:
1396 -- (n.disc1 /= typ.disc1) or else
1397 -- (n.disc2 /= typ.disc2) or else
1399 -- (n.discn /= typ.discn)
1401 Cond := Build_Discriminant_Checks (N, T_Typ);
1403 -- If Lhs is set and is a parameter, then the condition is
1404 -- guarded by: lhs'constrained and then (condition built above)
1406 if Present (Param_Entity (Lhs)) then
1410 Make_Attribute_Reference (Loc,
1411 Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc),
1412 Attribute_Name => Name_Constrained),
1413 Right_Opnd => Cond);
1417 Cond := Guard_Access (Cond, Loc, N);
1421 Make_Raise_Constraint_Error (Loc,
1423 Reason => CE_Discriminant_Check_Failed));
1424 end Apply_Discriminant_Check;
1426 ------------------------
1427 -- Apply_Divide_Check --
1428 ------------------------
1430 procedure Apply_Divide_Check (N : Node_Id) is
1431 Loc : constant Source_Ptr := Sloc (N);
1432 Typ : constant Entity_Id := Etype (N);
1433 Left : constant Node_Id := Left_Opnd (N);
1434 Right : constant Node_Id := Right_Opnd (N);
1444 pragma Warnings (Off, Lhi);
1445 -- Don't actually use this value
1449 and then not Backend_Divide_Checks_On_Target
1450 and then Check_Needed (Right, Division_Check)
1452 Determine_Range (Right, ROK, Rlo, Rhi, Assume_Valid => True);
1454 -- See if division by zero possible, and if so generate test. This
1455 -- part of the test is not controlled by the -gnato switch.
1457 if Do_Division_Check (N) then
1458 if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then
1460 Make_Raise_Constraint_Error (Loc,
1463 Left_Opnd => Duplicate_Subexpr_Move_Checks (Right),
1464 Right_Opnd => Make_Integer_Literal (Loc, 0)),
1465 Reason => CE_Divide_By_Zero));
1469 -- Test for extremely annoying case of xxx'First divided by -1
1471 if Do_Overflow_Check (N) then
1472 if Nkind (N) = N_Op_Divide
1473 and then Is_Signed_Integer_Type (Typ)
1475 Determine_Range (Left, LOK, Llo, Lhi, Assume_Valid => True);
1476 LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ)));
1478 if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi))
1480 ((not LOK) or else (Llo = LLB))
1483 Make_Raise_Constraint_Error (Loc,
1489 Duplicate_Subexpr_Move_Checks (Left),
1490 Right_Opnd => Make_Integer_Literal (Loc, LLB)),
1494 Duplicate_Subexpr (Right),
1496 Make_Integer_Literal (Loc, -1))),
1497 Reason => CE_Overflow_Check_Failed));
1502 end Apply_Divide_Check;
1504 ----------------------------------
1505 -- Apply_Float_Conversion_Check --
1506 ----------------------------------
1508 -- Let F and I be the source and target types of the conversion. The RM
1509 -- specifies that a floating-point value X is rounded to the nearest
1510 -- integer, with halfway cases being rounded away from zero. The rounded
1511 -- value of X is checked against I'Range.
1513 -- The catch in the above paragraph is that there is no good way to know
1514 -- whether the round-to-integer operation resulted in overflow. A remedy is
1515 -- to perform a range check in the floating-point domain instead, however:
1517 -- (1) The bounds may not be known at compile time
1518 -- (2) The check must take into account rounding or truncation.
1519 -- (3) The range of type I may not be exactly representable in F.
1520 -- (4) For the rounding case, The end-points I'First - 0.5 and
1521 -- I'Last + 0.5 may or may not be in range, depending on the
1522 -- sign of I'First and I'Last.
1523 -- (5) X may be a NaN, which will fail any comparison
1525 -- The following steps correctly convert X with rounding:
1527 -- (1) If either I'First or I'Last is not known at compile time, use
1528 -- I'Base instead of I in the next three steps and perform a
1529 -- regular range check against I'Range after conversion.
1530 -- (2) If I'First - 0.5 is representable in F then let Lo be that
1531 -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be
1532 -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First).
1533 -- In other words, take one of the closest floating-point numbers
1534 -- (which is an integer value) to I'First, and see if it is in
1536 -- (3) If I'Last + 0.5 is representable in F then let Hi be that value
1537 -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be
1538 -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last).
1539 -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo)
1540 -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi)
1542 -- For the truncating case, replace steps (2) and (3) as follows:
1543 -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK
1544 -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let
1546 -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK
1547 -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let
1550 procedure Apply_Float_Conversion_Check
1552 Target_Typ : Entity_Id)
1554 LB : constant Node_Id := Type_Low_Bound (Target_Typ);
1555 HB : constant Node_Id := Type_High_Bound (Target_Typ);
1556 Loc : constant Source_Ptr := Sloc (Ck_Node);
1557 Expr_Type : constant Entity_Id := Base_Type (Etype (Ck_Node));
1558 Target_Base : constant Entity_Id :=
1559 Implementation_Base_Type (Target_Typ);
1561 Par : constant Node_Id := Parent (Ck_Node);
1562 pragma Assert (Nkind (Par) = N_Type_Conversion);
1563 -- Parent of check node, must be a type conversion
1565 Truncate : constant Boolean := Float_Truncate (Par);
1566 Max_Bound : constant Uint :=
1568 (Machine_Radix_Value (Expr_Type),
1569 Machine_Mantissa_Value (Expr_Type) - 1) - 1;
1571 -- Largest bound, so bound plus or minus half is a machine number of F
1573 Ifirst, Ilast : Uint;
1574 -- Bounds of integer type
1577 -- Bounds to check in floating-point domain
1579 Lo_OK, Hi_OK : Boolean;
1580 -- True iff Lo resp. Hi belongs to I'Range
1582 Lo_Chk, Hi_Chk : Node_Id;
1583 -- Expressions that are False iff check fails
1585 Reason : RT_Exception_Code;
1588 if not Compile_Time_Known_Value (LB)
1589 or not Compile_Time_Known_Value (HB)
1592 -- First check that the value falls in the range of the base type,
1593 -- to prevent overflow during conversion and then perform a
1594 -- regular range check against the (dynamic) bounds.
1596 pragma Assert (Target_Base /= Target_Typ);
1598 Temp : constant Entity_Id := Make_Temporary (Loc, 'T', Par);
1601 Apply_Float_Conversion_Check (Ck_Node, Target_Base);
1602 Set_Etype (Temp, Target_Base);
1604 Insert_Action (Parent (Par),
1605 Make_Object_Declaration (Loc,
1606 Defining_Identifier => Temp,
1607 Object_Definition => New_Occurrence_Of (Target_Typ, Loc),
1608 Expression => New_Copy_Tree (Par)),
1609 Suppress => All_Checks);
1612 Make_Raise_Constraint_Error (Loc,
1615 Left_Opnd => New_Occurrence_Of (Temp, Loc),
1616 Right_Opnd => New_Occurrence_Of (Target_Typ, Loc)),
1617 Reason => CE_Range_Check_Failed));
1618 Rewrite (Par, New_Occurrence_Of (Temp, Loc));
1624 -- Get the (static) bounds of the target type
1626 Ifirst := Expr_Value (LB);
1627 Ilast := Expr_Value (HB);
1629 -- A simple optimization: if the expression is a universal literal,
1630 -- we can do the comparison with the bounds and the conversion to
1631 -- an integer type statically. The range checks are unchanged.
1633 if Nkind (Ck_Node) = N_Real_Literal
1634 and then Etype (Ck_Node) = Universal_Real
1635 and then Is_Integer_Type (Target_Typ)
1636 and then Nkind (Parent (Ck_Node)) = N_Type_Conversion
1639 Int_Val : constant Uint := UR_To_Uint (Realval (Ck_Node));
1642 if Int_Val <= Ilast and then Int_Val >= Ifirst then
1644 -- Conversion is safe
1646 Rewrite (Parent (Ck_Node),
1647 Make_Integer_Literal (Loc, UI_To_Int (Int_Val)));
1648 Analyze_And_Resolve (Parent (Ck_Node), Target_Typ);
1654 -- Check against lower bound
1656 if Truncate and then Ifirst > 0 then
1657 Lo := Pred (Expr_Type, UR_From_Uint (Ifirst));
1661 Lo := Succ (Expr_Type, UR_From_Uint (Ifirst - 1));
1664 elsif abs (Ifirst) < Max_Bound then
1665 Lo := UR_From_Uint (Ifirst) - Ureal_Half;
1666 Lo_OK := (Ifirst > 0);
1669 Lo := Machine (Expr_Type, UR_From_Uint (Ifirst), Round_Even, Ck_Node);
1670 Lo_OK := (Lo >= UR_From_Uint (Ifirst));
1675 -- Lo_Chk := (X >= Lo)
1677 Lo_Chk := Make_Op_Ge (Loc,
1678 Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
1679 Right_Opnd => Make_Real_Literal (Loc, Lo));
1682 -- Lo_Chk := (X > Lo)
1684 Lo_Chk := Make_Op_Gt (Loc,
1685 Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
1686 Right_Opnd => Make_Real_Literal (Loc, Lo));
1689 -- Check against higher bound
1691 if Truncate and then Ilast < 0 then
1692 Hi := Succ (Expr_Type, UR_From_Uint (Ilast));
1696 Hi := Pred (Expr_Type, UR_From_Uint (Ilast + 1));
1699 elsif abs (Ilast) < Max_Bound then
1700 Hi := UR_From_Uint (Ilast) + Ureal_Half;
1701 Hi_OK := (Ilast < 0);
1703 Hi := Machine (Expr_Type, UR_From_Uint (Ilast), Round_Even, Ck_Node);
1704 Hi_OK := (Hi <= UR_From_Uint (Ilast));
1709 -- Hi_Chk := (X <= Hi)
1711 Hi_Chk := Make_Op_Le (Loc,
1712 Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
1713 Right_Opnd => Make_Real_Literal (Loc, Hi));
1716 -- Hi_Chk := (X < Hi)
1718 Hi_Chk := Make_Op_Lt (Loc,
1719 Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
1720 Right_Opnd => Make_Real_Literal (Loc, Hi));
1723 -- If the bounds of the target type are the same as those of the base
1724 -- type, the check is an overflow check as a range check is not
1725 -- performed in these cases.
1727 if Expr_Value (Type_Low_Bound (Target_Base)) = Ifirst
1728 and then Expr_Value (Type_High_Bound (Target_Base)) = Ilast
1730 Reason := CE_Overflow_Check_Failed;
1732 Reason := CE_Range_Check_Failed;
1735 -- Raise CE if either conditions does not hold
1737 Insert_Action (Ck_Node,
1738 Make_Raise_Constraint_Error (Loc,
1739 Condition => Make_Op_Not (Loc, Make_And_Then (Loc, Lo_Chk, Hi_Chk)),
1741 end Apply_Float_Conversion_Check;
1743 ------------------------
1744 -- Apply_Length_Check --
1745 ------------------------
1747 procedure Apply_Length_Check
1749 Target_Typ : Entity_Id;
1750 Source_Typ : Entity_Id := Empty)
1753 Apply_Selected_Length_Checks
1754 (Ck_Node, Target_Typ, Source_Typ, Do_Static => False);
1755 end Apply_Length_Check;
1757 ---------------------------
1758 -- Apply_Predicate_Check --
1759 ---------------------------
1761 procedure Apply_Predicate_Check (N : Node_Id; Typ : Entity_Id) is
1763 if Present (Predicate_Function (Typ)) then
1765 Make_Predicate_Check (Typ, Duplicate_Subexpr (N)));
1767 end Apply_Predicate_Check;
1769 -----------------------
1770 -- Apply_Range_Check --
1771 -----------------------
1773 procedure Apply_Range_Check
1775 Target_Typ : Entity_Id;
1776 Source_Typ : Entity_Id := Empty)
1779 Apply_Selected_Range_Checks
1780 (Ck_Node, Target_Typ, Source_Typ, Do_Static => False);
1781 end Apply_Range_Check;
1783 ------------------------------
1784 -- Apply_Scalar_Range_Check --
1785 ------------------------------
1787 -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag
1788 -- off if it is already set on.
1790 procedure Apply_Scalar_Range_Check
1792 Target_Typ : Entity_Id;
1793 Source_Typ : Entity_Id := Empty;
1794 Fixed_Int : Boolean := False)
1796 Parnt : constant Node_Id := Parent (Expr);
1798 Arr : Node_Id := Empty; -- initialize to prevent warning
1799 Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning
1802 Is_Subscr_Ref : Boolean;
1803 -- Set true if Expr is a subscript
1805 Is_Unconstrained_Subscr_Ref : Boolean;
1806 -- Set true if Expr is a subscript of an unconstrained array. In this
1807 -- case we do not attempt to do an analysis of the value against the
1808 -- range of the subscript, since we don't know the actual subtype.
1811 -- Set to True if Expr should be regarded as a real value even though
1812 -- the type of Expr might be discrete.
1814 procedure Bad_Value;
1815 -- Procedure called if value is determined to be out of range
1821 procedure Bad_Value is
1823 Apply_Compile_Time_Constraint_Error
1824 (Expr, "value not in range of}?", CE_Range_Check_Failed,
1829 -- Start of processing for Apply_Scalar_Range_Check
1832 -- Return if check obviously not needed
1835 -- Not needed inside generic
1839 -- Not needed if previous error
1841 or else Target_Typ = Any_Type
1842 or else Nkind (Expr) = N_Error
1844 -- Not needed for non-scalar type
1846 or else not Is_Scalar_Type (Target_Typ)
1848 -- Not needed if we know node raises CE already
1850 or else Raises_Constraint_Error (Expr)
1855 -- Now, see if checks are suppressed
1858 Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component;
1860 if Is_Subscr_Ref then
1861 Arr := Prefix (Parnt);
1862 Arr_Typ := Get_Actual_Subtype_If_Available (Arr);
1865 if not Do_Range_Check (Expr) then
1867 -- Subscript reference. Check for Index_Checks suppressed
1869 if Is_Subscr_Ref then
1871 -- Check array type and its base type
1873 if Index_Checks_Suppressed (Arr_Typ)
1874 or else Index_Checks_Suppressed (Base_Type (Arr_Typ))
1878 -- Check array itself if it is an entity name
1880 elsif Is_Entity_Name (Arr)
1881 and then Index_Checks_Suppressed (Entity (Arr))
1885 -- Check expression itself if it is an entity name
1887 elsif Is_Entity_Name (Expr)
1888 and then Index_Checks_Suppressed (Entity (Expr))
1893 -- All other cases, check for Range_Checks suppressed
1896 -- Check target type and its base type
1898 if Range_Checks_Suppressed (Target_Typ)
1899 or else Range_Checks_Suppressed (Base_Type (Target_Typ))
1903 -- Check expression itself if it is an entity name
1905 elsif Is_Entity_Name (Expr)
1906 and then Range_Checks_Suppressed (Entity (Expr))
1910 -- If Expr is part of an assignment statement, then check left
1911 -- side of assignment if it is an entity name.
1913 elsif Nkind (Parnt) = N_Assignment_Statement
1914 and then Is_Entity_Name (Name (Parnt))
1915 and then Range_Checks_Suppressed (Entity (Name (Parnt)))
1922 -- Do not set range checks if they are killed
1924 if Nkind (Expr) = N_Unchecked_Type_Conversion
1925 and then Kill_Range_Check (Expr)
1930 -- Do not set range checks for any values from System.Scalar_Values
1931 -- since the whole idea of such values is to avoid checking them!
1933 if Is_Entity_Name (Expr)
1934 and then Is_RTU (Scope (Entity (Expr)), System_Scalar_Values)
1939 -- Now see if we need a check
1941 if No (Source_Typ) then
1942 S_Typ := Etype (Expr);
1944 S_Typ := Source_Typ;
1947 if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then
1951 Is_Unconstrained_Subscr_Ref :=
1952 Is_Subscr_Ref and then not Is_Constrained (Arr_Typ);
1954 -- Always do a range check if the source type includes infinities and
1955 -- the target type does not include infinities. We do not do this if
1956 -- range checks are killed.
1958 if Is_Floating_Point_Type (S_Typ)
1959 and then Has_Infinities (S_Typ)
1960 and then not Has_Infinities (Target_Typ)
1962 Enable_Range_Check (Expr);
1965 -- Return if we know expression is definitely in the range of the target
1966 -- type as determined by Determine_Range. Right now we only do this for
1967 -- discrete types, and not fixed-point or floating-point types.
1969 -- The additional less-precise tests below catch these cases
1971 -- Note: skip this if we are given a source_typ, since the point of
1972 -- supplying a Source_Typ is to stop us looking at the expression.
1973 -- We could sharpen this test to be out parameters only ???
1975 if Is_Discrete_Type (Target_Typ)
1976 and then Is_Discrete_Type (Etype (Expr))
1977 and then not Is_Unconstrained_Subscr_Ref
1978 and then No (Source_Typ)
1981 Tlo : constant Node_Id := Type_Low_Bound (Target_Typ);
1982 Thi : constant Node_Id := Type_High_Bound (Target_Typ);
1987 if Compile_Time_Known_Value (Tlo)
1988 and then Compile_Time_Known_Value (Thi)
1991 Lov : constant Uint := Expr_Value (Tlo);
1992 Hiv : constant Uint := Expr_Value (Thi);
1995 -- If range is null, we for sure have a constraint error
1996 -- (we don't even need to look at the value involved,
1997 -- since all possible values will raise CE).
2004 -- Otherwise determine range of value
2006 Determine_Range (Expr, OK, Lo, Hi, Assume_Valid => True);
2010 -- If definitely in range, all OK
2012 if Lo >= Lov and then Hi <= Hiv then
2015 -- If definitely not in range, warn
2017 elsif Lov > Hi or else Hiv < Lo then
2021 -- Otherwise we don't know
2033 Is_Floating_Point_Type (S_Typ)
2034 or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int);
2036 -- Check if we can determine at compile time whether Expr is in the
2037 -- range of the target type. Note that if S_Typ is within the bounds
2038 -- of Target_Typ then this must be the case. This check is meaningful
2039 -- only if this is not a conversion between integer and real types.
2041 if not Is_Unconstrained_Subscr_Ref
2043 Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ)
2045 (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int)
2047 Is_In_Range (Expr, Target_Typ,
2048 Assume_Valid => True,
2049 Fixed_Int => Fixed_Int,
2050 Int_Real => Int_Real))
2054 elsif Is_Out_Of_Range (Expr, Target_Typ,
2055 Assume_Valid => True,
2056 Fixed_Int => Fixed_Int,
2057 Int_Real => Int_Real)
2062 -- In the floating-point case, we only do range checks if the type is
2063 -- constrained. We definitely do NOT want range checks for unconstrained
2064 -- types, since we want to have infinities
2066 elsif Is_Floating_Point_Type (S_Typ) then
2067 if Is_Constrained (S_Typ) then
2068 Enable_Range_Check (Expr);
2071 -- For all other cases we enable a range check unconditionally
2074 Enable_Range_Check (Expr);
2077 end Apply_Scalar_Range_Check;
2079 ----------------------------------
2080 -- Apply_Selected_Length_Checks --
2081 ----------------------------------
2083 procedure Apply_Selected_Length_Checks
2085 Target_Typ : Entity_Id;
2086 Source_Typ : Entity_Id;
2087 Do_Static : Boolean)
2090 R_Result : Check_Result;
2093 Loc : constant Source_Ptr := Sloc (Ck_Node);
2094 Checks_On : constant Boolean :=
2095 (not Index_Checks_Suppressed (Target_Typ))
2097 (not Length_Checks_Suppressed (Target_Typ));
2100 if not Expander_Active then
2105 Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty);
2107 for J in 1 .. 2 loop
2108 R_Cno := R_Result (J);
2109 exit when No (R_Cno);
2111 -- A length check may mention an Itype which is attached to a
2112 -- subsequent node. At the top level in a package this can cause
2113 -- an order-of-elaboration problem, so we make sure that the itype
2114 -- is referenced now.
2116 if Ekind (Current_Scope) = E_Package
2117 and then Is_Compilation_Unit (Current_Scope)
2119 Ensure_Defined (Target_Typ, Ck_Node);
2121 if Present (Source_Typ) then
2122 Ensure_Defined (Source_Typ, Ck_Node);
2124 elsif Is_Itype (Etype (Ck_Node)) then
2125 Ensure_Defined (Etype (Ck_Node), Ck_Node);
2129 -- If the item is a conditional raise of constraint error, then have
2130 -- a look at what check is being performed and ???
2132 if Nkind (R_Cno) = N_Raise_Constraint_Error
2133 and then Present (Condition (R_Cno))
2135 Cond := Condition (R_Cno);
2137 -- Case where node does not now have a dynamic check
2139 if not Has_Dynamic_Length_Check (Ck_Node) then
2141 -- If checks are on, just insert the check
2144 Insert_Action (Ck_Node, R_Cno);
2146 if not Do_Static then
2147 Set_Has_Dynamic_Length_Check (Ck_Node);
2150 -- If checks are off, then analyze the length check after
2151 -- temporarily attaching it to the tree in case the relevant
2152 -- condition can be evaluated at compile time. We still want a
2153 -- compile time warning in this case.
2156 Set_Parent (R_Cno, Ck_Node);
2161 -- Output a warning if the condition is known to be True
2163 if Is_Entity_Name (Cond)
2164 and then Entity (Cond) = Standard_True
2166 Apply_Compile_Time_Constraint_Error
2167 (Ck_Node, "wrong length for array of}?",
2168 CE_Length_Check_Failed,
2172 -- If we were only doing a static check, or if checks are not
2173 -- on, then we want to delete the check, since it is not needed.
2174 -- We do this by replacing the if statement by a null statement
2176 elsif Do_Static or else not Checks_On then
2177 Remove_Warning_Messages (R_Cno);
2178 Rewrite (R_Cno, Make_Null_Statement (Loc));
2182 Install_Static_Check (R_Cno, Loc);
2185 end Apply_Selected_Length_Checks;
2187 ---------------------------------
2188 -- Apply_Selected_Range_Checks --
2189 ---------------------------------
2191 procedure Apply_Selected_Range_Checks
2193 Target_Typ : Entity_Id;
2194 Source_Typ : Entity_Id;
2195 Do_Static : Boolean)
2198 R_Result : Check_Result;
2201 Loc : constant Source_Ptr := Sloc (Ck_Node);
2202 Checks_On : constant Boolean :=
2203 (not Index_Checks_Suppressed (Target_Typ))
2205 (not Range_Checks_Suppressed (Target_Typ));
2208 if not Expander_Active or else not Checks_On then
2213 Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty);
2215 for J in 1 .. 2 loop
2217 R_Cno := R_Result (J);
2218 exit when No (R_Cno);
2220 -- If the item is a conditional raise of constraint error, then have
2221 -- a look at what check is being performed and ???
2223 if Nkind (R_Cno) = N_Raise_Constraint_Error
2224 and then Present (Condition (R_Cno))
2226 Cond := Condition (R_Cno);
2228 if not Has_Dynamic_Range_Check (Ck_Node) then
2229 Insert_Action (Ck_Node, R_Cno);
2231 if not Do_Static then
2232 Set_Has_Dynamic_Range_Check (Ck_Node);
2236 -- Output a warning if the condition is known to be True
2238 if Is_Entity_Name (Cond)
2239 and then Entity (Cond) = Standard_True
2241 -- Since an N_Range is technically not an expression, we have
2242 -- to set one of the bounds to C_E and then just flag the
2243 -- N_Range. The warning message will point to the lower bound
2244 -- and complain about a range, which seems OK.
2246 if Nkind (Ck_Node) = N_Range then
2247 Apply_Compile_Time_Constraint_Error
2248 (Low_Bound (Ck_Node), "static range out of bounds of}?",
2249 CE_Range_Check_Failed,
2253 Set_Raises_Constraint_Error (Ck_Node);
2256 Apply_Compile_Time_Constraint_Error
2257 (Ck_Node, "static value out of range of}?",
2258 CE_Range_Check_Failed,
2263 -- If we were only doing a static check, or if checks are not
2264 -- on, then we want to delete the check, since it is not needed.
2265 -- We do this by replacing the if statement by a null statement
2267 elsif Do_Static or else not Checks_On then
2268 Remove_Warning_Messages (R_Cno);
2269 Rewrite (R_Cno, Make_Null_Statement (Loc));
2273 Install_Static_Check (R_Cno, Loc);
2276 end Apply_Selected_Range_Checks;
2278 -------------------------------
2279 -- Apply_Static_Length_Check --
2280 -------------------------------
2282 procedure Apply_Static_Length_Check
2284 Target_Typ : Entity_Id;
2285 Source_Typ : Entity_Id := Empty)
2288 Apply_Selected_Length_Checks
2289 (Expr, Target_Typ, Source_Typ, Do_Static => True);
2290 end Apply_Static_Length_Check;
2292 -------------------------------------
2293 -- Apply_Subscript_Validity_Checks --
2294 -------------------------------------
2296 procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is
2300 pragma Assert (Nkind (Expr) = N_Indexed_Component);
2302 -- Loop through subscripts
2304 Sub := First (Expressions (Expr));
2305 while Present (Sub) loop
2307 -- Check one subscript. Note that we do not worry about enumeration
2308 -- type with holes, since we will convert the value to a Pos value
2309 -- for the subscript, and that convert will do the necessary validity
2312 Ensure_Valid (Sub, Holes_OK => True);
2314 -- Move to next subscript
2318 end Apply_Subscript_Validity_Checks;
2320 ----------------------------------
2321 -- Apply_Type_Conversion_Checks --
2322 ----------------------------------
2324 procedure Apply_Type_Conversion_Checks (N : Node_Id) is
2325 Target_Type : constant Entity_Id := Etype (N);
2326 Target_Base : constant Entity_Id := Base_Type (Target_Type);
2327 Expr : constant Node_Id := Expression (N);
2328 Expr_Type : constant Entity_Id := Etype (Expr);
2331 if Inside_A_Generic then
2334 -- Skip these checks if serious errors detected, there are some nasty
2335 -- situations of incomplete trees that blow things up.
2337 elsif Serious_Errors_Detected > 0 then
2340 -- Scalar type conversions of the form Target_Type (Expr) require a
2341 -- range check if we cannot be sure that Expr is in the base type of
2342 -- Target_Typ and also that Expr is in the range of Target_Typ. These
2343 -- are not quite the same condition from an implementation point of
2344 -- view, but clearly the second includes the first.
2346 elsif Is_Scalar_Type (Target_Type) then
2348 Conv_OK : constant Boolean := Conversion_OK (N);
2349 -- If the Conversion_OK flag on the type conversion is set and no
2350 -- floating point type is involved in the type conversion then
2351 -- fixed point values must be read as integral values.
2353 Float_To_Int : constant Boolean :=
2354 Is_Floating_Point_Type (Expr_Type)
2355 and then Is_Integer_Type (Target_Type);
2358 if not Overflow_Checks_Suppressed (Target_Base)
2360 In_Subrange_Of (Expr_Type, Target_Base, Fixed_Int => Conv_OK)
2361 and then not Float_To_Int
2363 Activate_Overflow_Check (N);
2366 if not Range_Checks_Suppressed (Target_Type)
2367 and then not Range_Checks_Suppressed (Expr_Type)
2369 if Float_To_Int then
2370 Apply_Float_Conversion_Check (Expr, Target_Type);
2372 Apply_Scalar_Range_Check
2373 (Expr, Target_Type, Fixed_Int => Conv_OK);
2378 elsif Comes_From_Source (N)
2379 and then not Discriminant_Checks_Suppressed (Target_Type)
2380 and then Is_Record_Type (Target_Type)
2381 and then Is_Derived_Type (Target_Type)
2382 and then not Is_Tagged_Type (Target_Type)
2383 and then not Is_Constrained (Target_Type)
2384 and then Present (Stored_Constraint (Target_Type))
2386 -- An unconstrained derived type may have inherited discriminant
2387 -- Build an actual discriminant constraint list using the stored
2388 -- constraint, to verify that the expression of the parent type
2389 -- satisfies the constraints imposed by the (unconstrained!)
2390 -- derived type. This applies to value conversions, not to view
2391 -- conversions of tagged types.
2394 Loc : constant Source_Ptr := Sloc (N);
2396 Constraint : Elmt_Id;
2397 Discr_Value : Node_Id;
2400 New_Constraints : constant Elist_Id := New_Elmt_List;
2401 Old_Constraints : constant Elist_Id :=
2402 Discriminant_Constraint (Expr_Type);
2405 Constraint := First_Elmt (Stored_Constraint (Target_Type));
2406 while Present (Constraint) loop
2407 Discr_Value := Node (Constraint);
2409 if Is_Entity_Name (Discr_Value)
2410 and then Ekind (Entity (Discr_Value)) = E_Discriminant
2412 Discr := Corresponding_Discriminant (Entity (Discr_Value));
2415 and then Scope (Discr) = Base_Type (Expr_Type)
2417 -- Parent is constrained by new discriminant. Obtain
2418 -- Value of original discriminant in expression. If the
2419 -- new discriminant has been used to constrain more than
2420 -- one of the stored discriminants, this will provide the
2421 -- required consistency check.
2424 (Make_Selected_Component (Loc,
2426 Duplicate_Subexpr_No_Checks
2427 (Expr, Name_Req => True),
2429 Make_Identifier (Loc, Chars (Discr))),
2433 -- Discriminant of more remote ancestor ???
2438 -- Derived type definition has an explicit value for this
2439 -- stored discriminant.
2443 (Duplicate_Subexpr_No_Checks (Discr_Value),
2447 Next_Elmt (Constraint);
2450 -- Use the unconstrained expression type to retrieve the
2451 -- discriminants of the parent, and apply momentarily the
2452 -- discriminant constraint synthesized above.
2454 Set_Discriminant_Constraint (Expr_Type, New_Constraints);
2455 Cond := Build_Discriminant_Checks (Expr, Expr_Type);
2456 Set_Discriminant_Constraint (Expr_Type, Old_Constraints);
2459 Make_Raise_Constraint_Error (Loc,
2461 Reason => CE_Discriminant_Check_Failed));
2464 -- For arrays, conversions are applied during expansion, to take into
2465 -- accounts changes of representation. The checks become range checks on
2466 -- the base type or length checks on the subtype, depending on whether
2467 -- the target type is unconstrained or constrained.
2472 end Apply_Type_Conversion_Checks;
2474 ----------------------------------------------
2475 -- Apply_Universal_Integer_Attribute_Checks --
2476 ----------------------------------------------
2478 procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is
2479 Loc : constant Source_Ptr := Sloc (N);
2480 Typ : constant Entity_Id := Etype (N);
2483 if Inside_A_Generic then
2486 -- Nothing to do if checks are suppressed
2488 elsif Range_Checks_Suppressed (Typ)
2489 and then Overflow_Checks_Suppressed (Typ)
2493 -- Nothing to do if the attribute does not come from source. The
2494 -- internal attributes we generate of this type do not need checks,
2495 -- and furthermore the attempt to check them causes some circular
2496 -- elaboration orders when dealing with packed types.
2498 elsif not Comes_From_Source (N) then
2501 -- If the prefix is a selected component that depends on a discriminant
2502 -- the check may improperly expose a discriminant instead of using
2503 -- the bounds of the object itself. Set the type of the attribute to
2504 -- the base type of the context, so that a check will be imposed when
2505 -- needed (e.g. if the node appears as an index).
2507 elsif Nkind (Prefix (N)) = N_Selected_Component
2508 and then Ekind (Typ) = E_Signed_Integer_Subtype
2509 and then Depends_On_Discriminant (Scalar_Range (Typ))
2511 Set_Etype (N, Base_Type (Typ));
2513 -- Otherwise, replace the attribute node with a type conversion node
2514 -- whose expression is the attribute, retyped to universal integer, and
2515 -- whose subtype mark is the target type. The call to analyze this
2516 -- conversion will set range and overflow checks as required for proper
2517 -- detection of an out of range value.
2520 Set_Etype (N, Universal_Integer);
2521 Set_Analyzed (N, True);
2524 Make_Type_Conversion (Loc,
2525 Subtype_Mark => New_Occurrence_Of (Typ, Loc),
2526 Expression => Relocate_Node (N)));
2528 Analyze_And_Resolve (N, Typ);
2531 end Apply_Universal_Integer_Attribute_Checks;
2533 -------------------------------
2534 -- Build_Discriminant_Checks --
2535 -------------------------------
2537 function Build_Discriminant_Checks
2539 T_Typ : Entity_Id) return Node_Id
2541 Loc : constant Source_Ptr := Sloc (N);
2544 Disc_Ent : Entity_Id;
2548 function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id;
2550 ----------------------------------
2551 -- Aggregate_Discriminant_Value --
2552 ----------------------------------
2554 function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id is
2558 -- The aggregate has been normalized with named associations. We use
2559 -- the Chars field to locate the discriminant to take into account
2560 -- discriminants in derived types, which carry the same name as those
2563 Assoc := First (Component_Associations (N));
2564 while Present (Assoc) loop
2565 if Chars (First (Choices (Assoc))) = Chars (Disc) then
2566 return Expression (Assoc);
2572 -- Discriminant must have been found in the loop above
2574 raise Program_Error;
2575 end Aggregate_Discriminant_Val;
2577 -- Start of processing for Build_Discriminant_Checks
2580 -- Loop through discriminants evolving the condition
2583 Disc := First_Elmt (Discriminant_Constraint (T_Typ));
2585 -- For a fully private type, use the discriminants of the parent type
2587 if Is_Private_Type (T_Typ)
2588 and then No (Full_View (T_Typ))
2590 Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ)));
2592 Disc_Ent := First_Discriminant (T_Typ);
2595 while Present (Disc) loop
2596 Dval := Node (Disc);
2598 if Nkind (Dval) = N_Identifier
2599 and then Ekind (Entity (Dval)) = E_Discriminant
2601 Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc);
2603 Dval := Duplicate_Subexpr_No_Checks (Dval);
2606 -- If we have an Unchecked_Union node, we can infer the discriminants
2609 if Is_Unchecked_Union (Base_Type (T_Typ)) then
2611 Get_Discriminant_Value (
2612 First_Discriminant (T_Typ),
2614 Stored_Constraint (T_Typ)));
2616 elsif Nkind (N) = N_Aggregate then
2618 Duplicate_Subexpr_No_Checks
2619 (Aggregate_Discriminant_Val (Disc_Ent));
2623 Make_Selected_Component (Loc,
2625 Duplicate_Subexpr_No_Checks (N, Name_Req => True),
2627 Make_Identifier (Loc, Chars (Disc_Ent)));
2629 Set_Is_In_Discriminant_Check (Dref);
2632 Evolve_Or_Else (Cond,
2635 Right_Opnd => Dval));
2638 Next_Discriminant (Disc_Ent);
2642 end Build_Discriminant_Checks;
2648 function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean is
2656 -- Always check if not simple entity
2658 if Nkind (Nod) not in N_Has_Entity
2659 or else not Comes_From_Source (Nod)
2664 -- Look up tree for short circuit
2671 -- Done if out of subexpression (note that we allow generated stuff
2672 -- such as itype declarations in this context, to keep the loop going
2673 -- since we may well have generated such stuff in complex situations.
2674 -- Also done if no parent (probably an error condition, but no point
2675 -- in behaving nasty if we find it!)
2678 or else (K not in N_Subexpr and then Comes_From_Source (P))
2682 -- Or/Or Else case, where test is part of the right operand, or is
2683 -- part of one of the actions associated with the right operand, and
2684 -- the left operand is an equality test.
2686 elsif K = N_Op_Or then
2687 exit when N = Right_Opnd (P)
2688 and then Nkind (Left_Opnd (P)) = N_Op_Eq;
2690 elsif K = N_Or_Else then
2691 exit when (N = Right_Opnd (P)
2694 and then List_Containing (N) = Actions (P)))
2695 and then Nkind (Left_Opnd (P)) = N_Op_Eq;
2697 -- Similar test for the And/And then case, where the left operand
2698 -- is an inequality test.
2700 elsif K = N_Op_And then
2701 exit when N = Right_Opnd (P)
2702 and then Nkind (Left_Opnd (P)) = N_Op_Ne;
2704 elsif K = N_And_Then then
2705 exit when (N = Right_Opnd (P)
2708 and then List_Containing (N) = Actions (P)))
2709 and then Nkind (Left_Opnd (P)) = N_Op_Ne;
2715 -- If we fall through the loop, then we have a conditional with an
2716 -- appropriate test as its left operand. So test further.
2719 R := Right_Opnd (L);
2722 -- Left operand of test must match original variable
2724 if Nkind (L) not in N_Has_Entity
2725 or else Entity (L) /= Entity (Nod)
2730 -- Right operand of test must be key value (zero or null)
2733 when Access_Check =>
2734 if not Known_Null (R) then
2738 when Division_Check =>
2739 if not Compile_Time_Known_Value (R)
2740 or else Expr_Value (R) /= Uint_0
2746 raise Program_Error;
2749 -- Here we have the optimizable case, warn if not short-circuited
2751 if K = N_Op_And or else K = N_Op_Or then
2753 when Access_Check =>
2755 ("Constraint_Error may be raised (access check)?",
2757 when Division_Check =>
2759 ("Constraint_Error may be raised (zero divide)?",
2763 raise Program_Error;
2766 if K = N_Op_And then
2767 Error_Msg_N -- CODEFIX
2768 ("use `AND THEN` instead of AND?", P);
2770 Error_Msg_N -- CODEFIX
2771 ("use `OR ELSE` instead of OR?", P);
2774 -- If not short-circuited, we need the check
2778 -- If short-circuited, we can omit the check
2785 -----------------------------------
2786 -- Check_Valid_Lvalue_Subscripts --
2787 -----------------------------------
2789 procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is
2791 -- Skip this if range checks are suppressed
2793 if Range_Checks_Suppressed (Etype (Expr)) then
2796 -- Only do this check for expressions that come from source. We assume
2797 -- that expander generated assignments explicitly include any necessary
2798 -- checks. Note that this is not just an optimization, it avoids
2799 -- infinite recursions!
2801 elsif not Comes_From_Source (Expr) then
2804 -- For a selected component, check the prefix
2806 elsif Nkind (Expr) = N_Selected_Component then
2807 Check_Valid_Lvalue_Subscripts (Prefix (Expr));
2810 -- Case of indexed component
2812 elsif Nkind (Expr) = N_Indexed_Component then
2813 Apply_Subscript_Validity_Checks (Expr);
2815 -- Prefix may itself be or contain an indexed component, and these
2816 -- subscripts need checking as well.
2818 Check_Valid_Lvalue_Subscripts (Prefix (Expr));
2820 end Check_Valid_Lvalue_Subscripts;
2822 ----------------------------------
2823 -- Null_Exclusion_Static_Checks --
2824 ----------------------------------
2826 procedure Null_Exclusion_Static_Checks (N : Node_Id) is
2827 Error_Node : Node_Id;
2829 Has_Null : constant Boolean := Has_Null_Exclusion (N);
2830 K : constant Node_Kind := Nkind (N);
2835 (K = N_Component_Declaration
2836 or else K = N_Discriminant_Specification
2837 or else K = N_Function_Specification
2838 or else K = N_Object_Declaration
2839 or else K = N_Parameter_Specification);
2841 if K = N_Function_Specification then
2842 Typ := Etype (Defining_Entity (N));
2844 Typ := Etype (Defining_Identifier (N));
2848 when N_Component_Declaration =>
2849 if Present (Access_Definition (Component_Definition (N))) then
2850 Error_Node := Component_Definition (N);
2852 Error_Node := Subtype_Indication (Component_Definition (N));
2855 when N_Discriminant_Specification =>
2856 Error_Node := Discriminant_Type (N);
2858 when N_Function_Specification =>
2859 Error_Node := Result_Definition (N);
2861 when N_Object_Declaration =>
2862 Error_Node := Object_Definition (N);
2864 when N_Parameter_Specification =>
2865 Error_Node := Parameter_Type (N);
2868 raise Program_Error;
2873 -- Enforce legality rule 3.10 (13): A null exclusion can only be
2874 -- applied to an access [sub]type.
2876 if not Is_Access_Type (Typ) then
2878 ("`NOT NULL` allowed only for an access type", Error_Node);
2880 -- Enforce legality rule RM 3.10(14/1): A null exclusion can only
2881 -- be applied to a [sub]type that does not exclude null already.
2883 elsif Can_Never_Be_Null (Typ)
2884 and then Comes_From_Source (Typ)
2887 ("`NOT NULL` not allowed (& already excludes null)",
2892 -- Check that null-excluding objects are always initialized, except for
2893 -- deferred constants, for which the expression will appear in the full
2896 if K = N_Object_Declaration
2897 and then No (Expression (N))
2898 and then not Constant_Present (N)
2899 and then not No_Initialization (N)
2901 -- Add an expression that assigns null. This node is needed by
2902 -- Apply_Compile_Time_Constraint_Error, which will replace this with
2903 -- a Constraint_Error node.
2905 Set_Expression (N, Make_Null (Sloc (N)));
2906 Set_Etype (Expression (N), Etype (Defining_Identifier (N)));
2908 Apply_Compile_Time_Constraint_Error
2909 (N => Expression (N),
2910 Msg => "(Ada 2005) null-excluding objects must be initialized?",
2911 Reason => CE_Null_Not_Allowed);
2914 -- Check that a null-excluding component, formal or object is not being
2915 -- assigned a null value. Otherwise generate a warning message and
2916 -- replace Expression (N) by an N_Constraint_Error node.
2918 if K /= N_Function_Specification then
2919 Expr := Expression (N);
2921 if Present (Expr) and then Known_Null (Expr) then
2923 when N_Component_Declaration |
2924 N_Discriminant_Specification =>
2925 Apply_Compile_Time_Constraint_Error
2927 Msg => "(Ada 2005) null not allowed " &
2928 "in null-excluding components?",
2929 Reason => CE_Null_Not_Allowed);
2931 when N_Object_Declaration =>
2932 Apply_Compile_Time_Constraint_Error
2934 Msg => "(Ada 2005) null not allowed " &
2935 "in null-excluding objects?",
2936 Reason => CE_Null_Not_Allowed);
2938 when N_Parameter_Specification =>
2939 Apply_Compile_Time_Constraint_Error
2941 Msg => "(Ada 2005) null not allowed " &
2942 "in null-excluding formals?",
2943 Reason => CE_Null_Not_Allowed);
2950 end Null_Exclusion_Static_Checks;
2952 ----------------------------------
2953 -- Conditional_Statements_Begin --
2954 ----------------------------------
2956 procedure Conditional_Statements_Begin is
2958 Saved_Checks_TOS := Saved_Checks_TOS + 1;
2960 -- If stack overflows, kill all checks, that way we know to simply reset
2961 -- the number of saved checks to zero on return. This should never occur
2964 if Saved_Checks_TOS > Saved_Checks_Stack'Last then
2967 -- In the normal case, we just make a new stack entry saving the current
2968 -- number of saved checks for a later restore.
2971 Saved_Checks_Stack (Saved_Checks_TOS) := Num_Saved_Checks;
2973 if Debug_Flag_CC then
2974 w ("Conditional_Statements_Begin: Num_Saved_Checks = ",
2978 end Conditional_Statements_Begin;
2980 --------------------------------
2981 -- Conditional_Statements_End --
2982 --------------------------------
2984 procedure Conditional_Statements_End is
2986 pragma Assert (Saved_Checks_TOS > 0);
2988 -- If the saved checks stack overflowed, then we killed all checks, so
2989 -- setting the number of saved checks back to zero is correct. This
2990 -- should never occur in practice.
2992 if Saved_Checks_TOS > Saved_Checks_Stack'Last then
2993 Num_Saved_Checks := 0;
2995 -- In the normal case, restore the number of saved checks from the top
2999 Num_Saved_Checks := Saved_Checks_Stack (Saved_Checks_TOS);
3000 if Debug_Flag_CC then
3001 w ("Conditional_Statements_End: Num_Saved_Checks = ",
3006 Saved_Checks_TOS := Saved_Checks_TOS - 1;
3007 end Conditional_Statements_End;
3009 ---------------------
3010 -- Determine_Range --
3011 ---------------------
3013 Cache_Size : constant := 2 ** 10;
3014 type Cache_Index is range 0 .. Cache_Size - 1;
3015 -- Determine size of below cache (power of 2 is more efficient!)
3017 Determine_Range_Cache_N : array (Cache_Index) of Node_Id;
3018 Determine_Range_Cache_V : array (Cache_Index) of Boolean;
3019 Determine_Range_Cache_Lo : array (Cache_Index) of Uint;
3020 Determine_Range_Cache_Hi : array (Cache_Index) of Uint;
3021 -- The above arrays are used to implement a small direct cache for
3022 -- Determine_Range calls. Because of the way Determine_Range recursively
3023 -- traces subexpressions, and because overflow checking calls the routine
3024 -- on the way up the tree, a quadratic behavior can otherwise be
3025 -- encountered in large expressions. The cache entry for node N is stored
3026 -- in the (N mod Cache_Size) entry, and can be validated by checking the
3027 -- actual node value stored there. The Range_Cache_V array records the
3028 -- setting of Assume_Valid for the cache entry.
3030 procedure Determine_Range
3035 Assume_Valid : Boolean := False)
3037 Typ : Entity_Id := Etype (N);
3038 -- Type to use, may get reset to base type for possibly invalid entity
3042 -- Lo and Hi bounds of left operand
3046 -- Lo and Hi bounds of right (or only) operand
3049 -- Temp variable used to hold a bound node
3052 -- High bound of base type of expression
3056 -- Refined values for low and high bounds, after tightening
3059 -- Used in lower level calls to indicate if call succeeded
3061 Cindex : Cache_Index;
3062 -- Used to search cache
3064 function OK_Operands return Boolean;
3065 -- Used for binary operators. Determines the ranges of the left and
3066 -- right operands, and if they are both OK, returns True, and puts
3067 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left.
3073 function OK_Operands return Boolean is
3076 (Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid);
3083 (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid);
3087 -- Start of processing for Determine_Range
3090 -- For temporary constants internally generated to remove side effects
3091 -- we must use the corresponding expression to determine the range of
3094 if Is_Entity_Name (N)
3095 and then Nkind (Parent (Entity (N))) = N_Object_Declaration
3096 and then Ekind (Entity (N)) = E_Constant
3097 and then Is_Internal_Name (Chars (Entity (N)))
3100 (Expression (Parent (Entity (N))), OK, Lo, Hi, Assume_Valid);
3104 -- Prevent junk warnings by initializing range variables
3111 -- If type is not defined, we can't determine its range
3115 -- We don't deal with anything except discrete types
3117 or else not Is_Discrete_Type (Typ)
3119 -- Ignore type for which an error has been posted, since range in
3120 -- this case may well be a bogosity deriving from the error. Also
3121 -- ignore if error posted on the reference node.
3123 or else Error_Posted (N) or else Error_Posted (Typ)
3129 -- For all other cases, we can determine the range
3133 -- If value is compile time known, then the possible range is the one
3134 -- value that we know this expression definitely has!
3136 if Compile_Time_Known_Value (N) then
3137 Lo := Expr_Value (N);
3142 -- Return if already in the cache
3144 Cindex := Cache_Index (N mod Cache_Size);
3146 if Determine_Range_Cache_N (Cindex) = N
3148 Determine_Range_Cache_V (Cindex) = Assume_Valid
3150 Lo := Determine_Range_Cache_Lo (Cindex);
3151 Hi := Determine_Range_Cache_Hi (Cindex);
3155 -- Otherwise, start by finding the bounds of the type of the expression,
3156 -- the value cannot be outside this range (if it is, then we have an
3157 -- overflow situation, which is a separate check, we are talking here
3158 -- only about the expression value).
3160 -- First a check, never try to find the bounds of a generic type, since
3161 -- these bounds are always junk values, and it is only valid to look at
3162 -- the bounds in an instance.
3164 if Is_Generic_Type (Typ) then
3169 -- First step, change to use base type unless we know the value is valid
3171 if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N)))
3172 or else Assume_No_Invalid_Values
3173 or else Assume_Valid
3177 Typ := Underlying_Type (Base_Type (Typ));
3180 -- We use the actual bound unless it is dynamic, in which case use the
3181 -- corresponding base type bound if possible. If we can't get a bound
3182 -- then we figure we can't determine the range (a peculiar case, that
3183 -- perhaps cannot happen, but there is no point in bombing in this
3184 -- optimization circuit.
3186 -- First the low bound
3188 Bound := Type_Low_Bound (Typ);
3190 if Compile_Time_Known_Value (Bound) then
3191 Lo := Expr_Value (Bound);
3193 elsif Compile_Time_Known_Value (Type_Low_Bound (Base_Type (Typ))) then
3194 Lo := Expr_Value (Type_Low_Bound (Base_Type (Typ)));
3201 -- Now the high bound
3203 Bound := Type_High_Bound (Typ);
3205 -- We need the high bound of the base type later on, and this should
3206 -- always be compile time known. Again, it is not clear that this
3207 -- can ever be false, but no point in bombing.
3209 if Compile_Time_Known_Value (Type_High_Bound (Base_Type (Typ))) then
3210 Hbound := Expr_Value (Type_High_Bound (Base_Type (Typ)));
3218 -- If we have a static subtype, then that may have a tighter bound so
3219 -- use the upper bound of the subtype instead in this case.
3221 if Compile_Time_Known_Value (Bound) then
3222 Hi := Expr_Value (Bound);
3225 -- We may be able to refine this value in certain situations. If any
3226 -- refinement is possible, then Lor and Hir are set to possibly tighter
3227 -- bounds, and OK1 is set to True.
3231 -- For unary plus, result is limited by range of operand
3235 (Right_Opnd (N), OK1, Lor, Hir, Assume_Valid);
3237 -- For unary minus, determine range of operand, and negate it
3241 (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid);
3248 -- For binary addition, get range of each operand and do the
3249 -- addition to get the result range.
3253 Lor := Lo_Left + Lo_Right;
3254 Hir := Hi_Left + Hi_Right;
3257 -- Division is tricky. The only case we consider is where the right
3258 -- operand is a positive constant, and in this case we simply divide
3259 -- the bounds of the left operand
3263 if Lo_Right = Hi_Right
3264 and then Lo_Right > 0
3266 Lor := Lo_Left / Lo_Right;
3267 Hir := Hi_Left / Lo_Right;
3274 -- For binary subtraction, get range of each operand and do the worst
3275 -- case subtraction to get the result range.
3277 when N_Op_Subtract =>
3279 Lor := Lo_Left - Hi_Right;
3280 Hir := Hi_Left - Lo_Right;
3283 -- For MOD, if right operand is a positive constant, then result must
3284 -- be in the allowable range of mod results.
3288 if Lo_Right = Hi_Right
3289 and then Lo_Right /= 0
3291 if Lo_Right > 0 then
3293 Hir := Lo_Right - 1;
3295 else -- Lo_Right < 0
3296 Lor := Lo_Right + 1;
3305 -- For REM, if right operand is a positive constant, then result must
3306 -- be in the allowable range of mod results.
3310 if Lo_Right = Hi_Right
3311 and then Lo_Right /= 0
3314 Dval : constant Uint := (abs Lo_Right) - 1;
3317 -- The sign of the result depends on the sign of the
3318 -- dividend (but not on the sign of the divisor, hence
3319 -- the abs operation above).
3339 -- Attribute reference cases
3341 when N_Attribute_Reference =>
3342 case Attribute_Name (N) is
3344 -- For Pos/Val attributes, we can refine the range using the
3345 -- possible range of values of the attribute expression.
3347 when Name_Pos | Name_Val =>
3349 (First (Expressions (N)), OK1, Lor, Hir, Assume_Valid);
3351 -- For Length attribute, use the bounds of the corresponding
3352 -- index type to refine the range.
3356 Atyp : Entity_Id := Etype (Prefix (N));
3364 if Is_Access_Type (Atyp) then
3365 Atyp := Designated_Type (Atyp);
3368 -- For string literal, we know exact value
3370 if Ekind (Atyp) = E_String_Literal_Subtype then
3372 Lo := String_Literal_Length (Atyp);
3373 Hi := String_Literal_Length (Atyp);
3377 -- Otherwise check for expression given
3379 if No (Expressions (N)) then
3383 UI_To_Int (Expr_Value (First (Expressions (N))));
3386 Indx := First_Index (Atyp);
3387 for J in 2 .. Inum loop
3388 Indx := Next_Index (Indx);
3391 -- If the index type is a formal type or derived from
3392 -- one, the bounds are not static.
3394 if Is_Generic_Type (Root_Type (Etype (Indx))) then
3400 (Type_Low_Bound (Etype (Indx)), OK1, LL, LU,
3405 (Type_High_Bound (Etype (Indx)), OK1, UL, UU,
3410 -- The maximum value for Length is the biggest
3411 -- possible gap between the values of the bounds.
3412 -- But of course, this value cannot be negative.
3414 Hir := UI_Max (Uint_0, UU - LL + 1);
3416 -- For constrained arrays, the minimum value for
3417 -- Length is taken from the actual value of the
3418 -- bounds, since the index will be exactly of this
3421 if Is_Constrained (Atyp) then
3422 Lor := UI_Max (Uint_0, UL - LU + 1);
3424 -- For an unconstrained array, the minimum value
3425 -- for length is always zero.
3434 -- No special handling for other attributes
3435 -- Probably more opportunities exist here???
3442 -- For type conversion from one discrete type to another, we can
3443 -- refine the range using the converted value.
3445 when N_Type_Conversion =>
3446 Determine_Range (Expression (N), OK1, Lor, Hir, Assume_Valid);
3448 -- Nothing special to do for all other expression kinds
3456 -- At this stage, if OK1 is true, then we know that the actual result of
3457 -- the computed expression is in the range Lor .. Hir. We can use this
3458 -- to restrict the possible range of results.
3460 -- If one of the computed bounds is outside the range of the base type,
3461 -- the expression may raise an exception and we better indicate that
3462 -- the evaluation has failed, at least if checks are enabled.
3464 if Enable_Overflow_Checks
3465 and then not Is_Entity_Name (N)
3466 and then (Lor < Lo or else Hir > Hi)
3474 -- If the refined value of the low bound is greater than the type
3475 -- high bound, then reset it to the more restrictive value. However,
3476 -- we do NOT do this for the case of a modular type where the
3477 -- possible upper bound on the value is above the base type high
3478 -- bound, because that means the result could wrap.
3481 and then not (Is_Modular_Integer_Type (Typ) and then Hir > Hbound)
3486 -- Similarly, if the refined value of the high bound is less than the
3487 -- value so far, then reset it to the more restrictive value. Again,
3488 -- we do not do this if the refined low bound is negative for a
3489 -- modular type, since this would wrap.
3492 and then not (Is_Modular_Integer_Type (Typ) and then Lor < Uint_0)
3498 -- Set cache entry for future call and we are all done
3500 Determine_Range_Cache_N (Cindex) := N;
3501 Determine_Range_Cache_V (Cindex) := Assume_Valid;
3502 Determine_Range_Cache_Lo (Cindex) := Lo;
3503 Determine_Range_Cache_Hi (Cindex) := Hi;
3506 -- If any exception occurs, it means that we have some bug in the compiler,
3507 -- possibly triggered by a previous error, or by some unforeseen peculiar
3508 -- occurrence. However, this is only an optimization attempt, so there is
3509 -- really no point in crashing the compiler. Instead we just decide, too
3510 -- bad, we can't figure out a range in this case after all.
3515 -- Debug flag K disables this behavior (useful for debugging)
3517 if Debug_Flag_K then
3525 end Determine_Range;
3527 ------------------------------------
3528 -- Discriminant_Checks_Suppressed --
3529 ------------------------------------
3531 function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is
3534 if Is_Unchecked_Union (E) then
3536 elsif Checks_May_Be_Suppressed (E) then
3537 return Is_Check_Suppressed (E, Discriminant_Check);
3541 return Scope_Suppress (Discriminant_Check);
3542 end Discriminant_Checks_Suppressed;
3544 --------------------------------
3545 -- Division_Checks_Suppressed --
3546 --------------------------------
3548 function Division_Checks_Suppressed (E : Entity_Id) return Boolean is
3550 if Present (E) and then Checks_May_Be_Suppressed (E) then
3551 return Is_Check_Suppressed (E, Division_Check);
3553 return Scope_Suppress (Division_Check);
3555 end Division_Checks_Suppressed;
3557 -----------------------------------
3558 -- Elaboration_Checks_Suppressed --
3559 -----------------------------------
3561 function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is
3563 -- The complication in this routine is that if we are in the dynamic
3564 -- model of elaboration, we also check All_Checks, since All_Checks
3565 -- does not set Elaboration_Check explicitly.
3568 if Kill_Elaboration_Checks (E) then
3571 elsif Checks_May_Be_Suppressed (E) then
3572 if Is_Check_Suppressed (E, Elaboration_Check) then
3574 elsif Dynamic_Elaboration_Checks then
3575 return Is_Check_Suppressed (E, All_Checks);
3582 if Scope_Suppress (Elaboration_Check) then
3584 elsif Dynamic_Elaboration_Checks then
3585 return Scope_Suppress (All_Checks);
3589 end Elaboration_Checks_Suppressed;
3591 ---------------------------
3592 -- Enable_Overflow_Check --
3593 ---------------------------
3595 procedure Enable_Overflow_Check (N : Node_Id) is
3596 Typ : constant Entity_Id := Base_Type (Etype (N));
3605 if Debug_Flag_CC then
3606 w ("Enable_Overflow_Check for node ", Int (N));
3607 Write_Str (" Source location = ");
3612 -- No check if overflow checks suppressed for type of node
3614 if Present (Etype (N))
3615 and then Overflow_Checks_Suppressed (Etype (N))
3619 -- Nothing to do for unsigned integer types, which do not overflow
3621 elsif Is_Modular_Integer_Type (Typ) then
3624 -- Nothing to do if the range of the result is known OK. We skip this
3625 -- for conversions, since the caller already did the check, and in any
3626 -- case the condition for deleting the check for a type conversion is
3629 elsif Nkind (N) /= N_Type_Conversion then
3630 Determine_Range (N, OK, Lo, Hi, Assume_Valid => True);
3632 -- Note in the test below that we assume that the range is not OK
3633 -- if a bound of the range is equal to that of the type. That's not
3634 -- quite accurate but we do this for the following reasons:
3636 -- a) The way that Determine_Range works, it will typically report
3637 -- the bounds of the value as being equal to the bounds of the
3638 -- type, because it either can't tell anything more precise, or
3639 -- does not think it is worth the effort to be more precise.
3641 -- b) It is very unusual to have a situation in which this would
3642 -- generate an unnecessary overflow check (an example would be
3643 -- a subtype with a range 0 .. Integer'Last - 1 to which the
3644 -- literal value one is added).
3646 -- c) The alternative is a lot of special casing in this routine
3647 -- which would partially duplicate Determine_Range processing.
3650 and then Lo > Expr_Value (Type_Low_Bound (Typ))
3651 and then Hi < Expr_Value (Type_High_Bound (Typ))
3653 if Debug_Flag_CC then
3654 w ("No overflow check required");
3661 -- If not in optimizing mode, set flag and we are done. We are also done
3662 -- (and just set the flag) if the type is not a discrete type, since it
3663 -- is not worth the effort to eliminate checks for other than discrete
3664 -- types. In addition, we take this same path if we have stored the
3665 -- maximum number of checks possible already (a very unlikely situation,
3666 -- but we do not want to blow up!)
3668 if Optimization_Level = 0
3669 or else not Is_Discrete_Type (Etype (N))
3670 or else Num_Saved_Checks = Saved_Checks'Last
3672 Activate_Overflow_Check (N);
3674 if Debug_Flag_CC then
3675 w ("Optimization off");
3681 -- Otherwise evaluate and check the expression
3686 Target_Type => Empty,
3692 if Debug_Flag_CC then
3693 w ("Called Find_Check");
3697 w (" Check_Num = ", Chk);
3698 w (" Ent = ", Int (Ent));
3699 Write_Str (" Ofs = ");
3704 -- If check is not of form to optimize, then set flag and we are done
3707 Activate_Overflow_Check (N);
3711 -- If check is already performed, then return without setting flag
3714 if Debug_Flag_CC then
3715 w ("Check suppressed!");
3721 -- Here we will make a new entry for the new check
3723 Activate_Overflow_Check (N);
3724 Num_Saved_Checks := Num_Saved_Checks + 1;
3725 Saved_Checks (Num_Saved_Checks) :=
3730 Target_Type => Empty);
3732 if Debug_Flag_CC then
3733 w ("Make new entry, check number = ", Num_Saved_Checks);
3734 w (" Entity = ", Int (Ent));
3735 Write_Str (" Offset = ");
3737 w (" Check_Type = O");
3738 w (" Target_Type = Empty");
3741 -- If we get an exception, then something went wrong, probably because of
3742 -- an error in the structure of the tree due to an incorrect program. Or it
3743 -- may be a bug in the optimization circuit. In either case the safest
3744 -- thing is simply to set the check flag unconditionally.
3748 Activate_Overflow_Check (N);
3750 if Debug_Flag_CC then
3751 w (" exception occurred, overflow flag set");
3755 end Enable_Overflow_Check;
3757 ------------------------
3758 -- Enable_Range_Check --
3759 ------------------------
3761 procedure Enable_Range_Check (N : Node_Id) is
3770 -- Return if unchecked type conversion with range check killed. In this
3771 -- case we never set the flag (that's what Kill_Range_Check is about!)
3773 if Nkind (N) = N_Unchecked_Type_Conversion
3774 and then Kill_Range_Check (N)
3779 -- Do not set range check flag if parent is assignment statement or
3780 -- object declaration with Suppress_Assignment_Checks flag set
3782 if Nkind_In (Parent (N), N_Assignment_Statement, N_Object_Declaration)
3783 and then Suppress_Assignment_Checks (Parent (N))
3788 -- Check for various cases where we should suppress the range check
3790 -- No check if range checks suppressed for type of node
3792 if Present (Etype (N))
3793 and then Range_Checks_Suppressed (Etype (N))
3797 -- No check if node is an entity name, and range checks are suppressed
3798 -- for this entity, or for the type of this entity.
3800 elsif Is_Entity_Name (N)
3801 and then (Range_Checks_Suppressed (Entity (N))
3802 or else Range_Checks_Suppressed (Etype (Entity (N))))
3806 -- No checks if index of array, and index checks are suppressed for
3807 -- the array object or the type of the array.
3809 elsif Nkind (Parent (N)) = N_Indexed_Component then
3811 Pref : constant Node_Id := Prefix (Parent (N));
3813 if Is_Entity_Name (Pref)
3814 and then Index_Checks_Suppressed (Entity (Pref))
3817 elsif Index_Checks_Suppressed (Etype (Pref)) then
3823 -- Debug trace output
3825 if Debug_Flag_CC then
3826 w ("Enable_Range_Check for node ", Int (N));
3827 Write_Str (" Source location = ");
3832 -- If not in optimizing mode, set flag and we are done. We are also done
3833 -- (and just set the flag) if the type is not a discrete type, since it
3834 -- is not worth the effort to eliminate checks for other than discrete
3835 -- types. In addition, we take this same path if we have stored the
3836 -- maximum number of checks possible already (a very unlikely situation,
3837 -- but we do not want to blow up!)
3839 if Optimization_Level = 0
3840 or else No (Etype (N))
3841 or else not Is_Discrete_Type (Etype (N))
3842 or else Num_Saved_Checks = Saved_Checks'Last
3844 Activate_Range_Check (N);
3846 if Debug_Flag_CC then
3847 w ("Optimization off");
3853 -- Otherwise find out the target type
3857 -- For assignment, use left side subtype
3859 if Nkind (P) = N_Assignment_Statement
3860 and then Expression (P) = N
3862 Ttyp := Etype (Name (P));
3864 -- For indexed component, use subscript subtype
3866 elsif Nkind (P) = N_Indexed_Component then
3873 Atyp := Etype (Prefix (P));
3875 if Is_Access_Type (Atyp) then
3876 Atyp := Designated_Type (Atyp);
3878 -- If the prefix is an access to an unconstrained array,
3879 -- perform check unconditionally: it depends on the bounds of
3880 -- an object and we cannot currently recognize whether the test
3881 -- may be redundant.
3883 if not Is_Constrained (Atyp) then
3884 Activate_Range_Check (N);
3888 -- Ditto if the prefix is an explicit dereference whose designated
3889 -- type is unconstrained.
3891 elsif Nkind (Prefix (P)) = N_Explicit_Dereference
3892 and then not Is_Constrained (Atyp)
3894 Activate_Range_Check (N);
3898 Indx := First_Index (Atyp);
3899 Subs := First (Expressions (P));
3902 Ttyp := Etype (Indx);
3911 -- For now, ignore all other cases, they are not so interesting
3914 if Debug_Flag_CC then
3915 w (" target type not found, flag set");
3918 Activate_Range_Check (N);
3922 -- Evaluate and check the expression
3927 Target_Type => Ttyp,
3933 if Debug_Flag_CC then
3934 w ("Called Find_Check");
3935 w ("Target_Typ = ", Int (Ttyp));
3939 w (" Check_Num = ", Chk);
3940 w (" Ent = ", Int (Ent));
3941 Write_Str (" Ofs = ");
3946 -- If check is not of form to optimize, then set flag and we are done
3949 if Debug_Flag_CC then
3950 w (" expression not of optimizable type, flag set");
3953 Activate_Range_Check (N);
3957 -- If check is already performed, then return without setting flag
3960 if Debug_Flag_CC then
3961 w ("Check suppressed!");
3967 -- Here we will make a new entry for the new check
3969 Activate_Range_Check (N);
3970 Num_Saved_Checks := Num_Saved_Checks + 1;
3971 Saved_Checks (Num_Saved_Checks) :=
3976 Target_Type => Ttyp);
3978 if Debug_Flag_CC then
3979 w ("Make new entry, check number = ", Num_Saved_Checks);
3980 w (" Entity = ", Int (Ent));
3981 Write_Str (" Offset = ");
3983 w (" Check_Type = R");
3984 w (" Target_Type = ", Int (Ttyp));
3985 pg (Union_Id (Ttyp));
3988 -- If we get an exception, then something went wrong, probably because of
3989 -- an error in the structure of the tree due to an incorrect program. Or
3990 -- it may be a bug in the optimization circuit. In either case the safest
3991 -- thing is simply to set the check flag unconditionally.
3995 Activate_Range_Check (N);
3997 if Debug_Flag_CC then
3998 w (" exception occurred, range flag set");
4002 end Enable_Range_Check;
4008 procedure Ensure_Valid (Expr : Node_Id; Holes_OK : Boolean := False) is
4009 Typ : constant Entity_Id := Etype (Expr);
4012 -- Ignore call if we are not doing any validity checking
4014 if not Validity_Checks_On then
4017 -- Ignore call if range or validity checks suppressed on entity or type
4019 elsif Range_Or_Validity_Checks_Suppressed (Expr) then
4022 -- No check required if expression is from the expander, we assume the
4023 -- expander will generate whatever checks are needed. Note that this is
4024 -- not just an optimization, it avoids infinite recursions!
4026 -- Unchecked conversions must be checked, unless they are initialized
4027 -- scalar values, as in a component assignment in an init proc.
4029 -- In addition, we force a check if Force_Validity_Checks is set
4031 elsif not Comes_From_Source (Expr)
4032 and then not Force_Validity_Checks
4033 and then (Nkind (Expr) /= N_Unchecked_Type_Conversion
4034 or else Kill_Range_Check (Expr))
4038 -- No check required if expression is known to have valid value
4040 elsif Expr_Known_Valid (Expr) then
4043 -- Ignore case of enumeration with holes where the flag is set not to
4044 -- worry about holes, since no special validity check is needed
4046 elsif Is_Enumeration_Type (Typ)
4047 and then Has_Non_Standard_Rep (Typ)
4052 -- No check required on the left-hand side of an assignment
4054 elsif Nkind (Parent (Expr)) = N_Assignment_Statement
4055 and then Expr = Name (Parent (Expr))
4059 -- No check on a universal real constant. The context will eventually
4060 -- convert it to a machine number for some target type, or report an
4063 elsif Nkind (Expr) = N_Real_Literal
4064 and then Etype (Expr) = Universal_Real
4068 -- If the expression denotes a component of a packed boolean array,
4069 -- no possible check applies. We ignore the old ACATS chestnuts that
4070 -- involve Boolean range True..True.
4072 -- Note: validity checks are generated for expressions that yield a
4073 -- scalar type, when it is possible to create a value that is outside of
4074 -- the type. If this is a one-bit boolean no such value exists. This is
4075 -- an optimization, and it also prevents compiler blowing up during the
4076 -- elaboration of improperly expanded packed array references.
4078 elsif Nkind (Expr) = N_Indexed_Component
4079 and then Is_Bit_Packed_Array (Etype (Prefix (Expr)))
4080 and then Root_Type (Etype (Expr)) = Standard_Boolean
4084 -- An annoying special case. If this is an out parameter of a scalar
4085 -- type, then the value is not going to be accessed, therefore it is
4086 -- inappropriate to do any validity check at the call site.
4089 -- Only need to worry about scalar types
4091 if Is_Scalar_Type (Typ) then
4101 -- Find actual argument (which may be a parameter association)
4102 -- and the parent of the actual argument (the call statement)
4107 if Nkind (P) = N_Parameter_Association then
4112 -- Only need to worry if we are argument of a procedure call
4113 -- since functions don't have out parameters. If this is an
4114 -- indirect or dispatching call, get signature from the
4117 if Nkind (P) = N_Procedure_Call_Statement then
4118 L := Parameter_Associations (P);
4120 if Is_Entity_Name (Name (P)) then
4121 E := Entity (Name (P));
4123 pragma Assert (Nkind (Name (P)) = N_Explicit_Dereference);
4124 E := Etype (Name (P));
4127 -- Only need to worry if there are indeed actuals, and if
4128 -- this could be a procedure call, otherwise we cannot get a
4129 -- match (either we are not an argument, or the mode of the
4130 -- formal is not OUT). This test also filters out the
4133 if Is_Non_Empty_List (L)
4134 and then Is_Subprogram (E)
4136 -- This is the loop through parameters, looking for an
4137 -- OUT parameter for which we are the argument.
4139 F := First_Formal (E);
4141 while Present (F) loop
4142 if Ekind (F) = E_Out_Parameter and then A = N then
4155 -- If this is a boolean expression, only its elementary operands need
4156 -- checking: if they are valid, a boolean or short-circuit operation
4157 -- with them will be valid as well.
4159 if Base_Type (Typ) = Standard_Boolean
4161 (Nkind (Expr) in N_Op or else Nkind (Expr) in N_Short_Circuit)
4166 -- If we fall through, a validity check is required
4168 Insert_Valid_Check (Expr);
4170 if Is_Entity_Name (Expr)
4171 and then Safe_To_Capture_Value (Expr, Entity (Expr))
4173 Set_Is_Known_Valid (Entity (Expr));
4177 ----------------------
4178 -- Expr_Known_Valid --
4179 ----------------------
4181 function Expr_Known_Valid (Expr : Node_Id) return Boolean is
4182 Typ : constant Entity_Id := Etype (Expr);
4185 -- Non-scalar types are always considered valid, since they never give
4186 -- rise to the issues of erroneous or bounded error behavior that are
4187 -- the concern. In formal reference manual terms the notion of validity
4188 -- only applies to scalar types. Note that even when packed arrays are
4189 -- represented using modular types, they are still arrays semantically,
4190 -- so they are also always valid (in particular, the unused bits can be
4191 -- random rubbish without affecting the validity of the array value).
4193 if not Is_Scalar_Type (Typ) or else Is_Packed_Array_Type (Typ) then
4196 -- If no validity checking, then everything is considered valid
4198 elsif not Validity_Checks_On then
4201 -- Floating-point types are considered valid unless floating-point
4202 -- validity checks have been specifically turned on.
4204 elsif Is_Floating_Point_Type (Typ)
4205 and then not Validity_Check_Floating_Point
4209 -- If the expression is the value of an object that is known to be
4210 -- valid, then clearly the expression value itself is valid.
4212 elsif Is_Entity_Name (Expr)
4213 and then Is_Known_Valid (Entity (Expr))
4217 -- References to discriminants are always considered valid. The value
4218 -- of a discriminant gets checked when the object is built. Within the
4219 -- record, we consider it valid, and it is important to do so, since
4220 -- otherwise we can try to generate bogus validity checks which
4221 -- reference discriminants out of scope. Discriminants of concurrent
4222 -- types are excluded for the same reason.
4224 elsif Is_Entity_Name (Expr)
4225 and then Denotes_Discriminant (Expr, Check_Concurrent => True)
4229 -- If the type is one for which all values are known valid, then we are
4230 -- sure that the value is valid except in the slightly odd case where
4231 -- the expression is a reference to a variable whose size has been
4232 -- explicitly set to a value greater than the object size.
4234 elsif Is_Known_Valid (Typ) then
4235 if Is_Entity_Name (Expr)
4236 and then Ekind (Entity (Expr)) = E_Variable
4237 and then Esize (Entity (Expr)) > Esize (Typ)
4244 -- Integer and character literals always have valid values, where
4245 -- appropriate these will be range checked in any case.
4247 elsif Nkind (Expr) = N_Integer_Literal
4249 Nkind (Expr) = N_Character_Literal
4253 -- If we have a type conversion or a qualification of a known valid
4254 -- value, then the result will always be valid.
4256 elsif Nkind (Expr) = N_Type_Conversion
4258 Nkind (Expr) = N_Qualified_Expression
4260 return Expr_Known_Valid (Expression (Expr));
4262 -- The result of any operator is always considered valid, since we
4263 -- assume the necessary checks are done by the operator. For operators
4264 -- on floating-point operations, we must also check when the operation
4265 -- is the right-hand side of an assignment, or is an actual in a call.
4267 elsif Nkind (Expr) in N_Op then
4268 if Is_Floating_Point_Type (Typ)
4269 and then Validity_Check_Floating_Point
4271 (Nkind (Parent (Expr)) = N_Assignment_Statement
4272 or else Nkind (Parent (Expr)) = N_Function_Call
4273 or else Nkind (Parent (Expr)) = N_Parameter_Association)
4280 -- The result of a membership test is always valid, since it is true or
4281 -- false, there are no other possibilities.
4283 elsif Nkind (Expr) in N_Membership_Test then
4286 -- For all other cases, we do not know the expression is valid
4291 end Expr_Known_Valid;
4297 procedure Find_Check
4299 Check_Type : Character;
4300 Target_Type : Entity_Id;
4301 Entry_OK : out Boolean;
4302 Check_Num : out Nat;
4303 Ent : out Entity_Id;
4306 function Within_Range_Of
4307 (Target_Type : Entity_Id;
4308 Check_Type : Entity_Id) return Boolean;
4309 -- Given a requirement for checking a range against Target_Type, and
4310 -- and a range Check_Type against which a check has already been made,
4311 -- determines if the check against check type is sufficient to ensure
4312 -- that no check against Target_Type is required.
4314 ---------------------
4315 -- Within_Range_Of --
4316 ---------------------
4318 function Within_Range_Of
4319 (Target_Type : Entity_Id;
4320 Check_Type : Entity_Id) return Boolean
4323 if Target_Type = Check_Type then
4328 Tlo : constant Node_Id := Type_Low_Bound (Target_Type);
4329 Thi : constant Node_Id := Type_High_Bound (Target_Type);
4330 Clo : constant Node_Id := Type_Low_Bound (Check_Type);
4331 Chi : constant Node_Id := Type_High_Bound (Check_Type);
4335 or else (Compile_Time_Known_Value (Tlo)
4337 Compile_Time_Known_Value (Clo)
4339 Expr_Value (Clo) >= Expr_Value (Tlo)))
4342 or else (Compile_Time_Known_Value (Thi)
4344 Compile_Time_Known_Value (Chi)
4346 Expr_Value (Chi) <= Expr_Value (Clo)))
4354 end Within_Range_Of;
4356 -- Start of processing for Find_Check
4359 -- Establish default, in case no entry is found
4363 -- Case of expression is simple entity reference
4365 if Is_Entity_Name (Expr) then
4366 Ent := Entity (Expr);
4369 -- Case of expression is entity + known constant
4371 elsif Nkind (Expr) = N_Op_Add
4372 and then Compile_Time_Known_Value (Right_Opnd (Expr))
4373 and then Is_Entity_Name (Left_Opnd (Expr))
4375 Ent := Entity (Left_Opnd (Expr));
4376 Ofs := Expr_Value (Right_Opnd (Expr));
4378 -- Case of expression is entity - known constant
4380 elsif Nkind (Expr) = N_Op_Subtract
4381 and then Compile_Time_Known_Value (Right_Opnd (Expr))
4382 and then Is_Entity_Name (Left_Opnd (Expr))
4384 Ent := Entity (Left_Opnd (Expr));
4385 Ofs := UI_Negate (Expr_Value (Right_Opnd (Expr)));
4387 -- Any other expression is not of the right form
4396 -- Come here with expression of appropriate form, check if entity is an
4397 -- appropriate one for our purposes.
4399 if (Ekind (Ent) = E_Variable
4400 or else Is_Constant_Object (Ent))
4401 and then not Is_Library_Level_Entity (Ent)
4409 -- See if there is matching check already
4411 for J in reverse 1 .. Num_Saved_Checks loop
4413 SC : Saved_Check renames Saved_Checks (J);
4416 if SC.Killed = False
4417 and then SC.Entity = Ent
4418 and then SC.Offset = Ofs
4419 and then SC.Check_Type = Check_Type
4420 and then Within_Range_Of (Target_Type, SC.Target_Type)
4428 -- If we fall through entry was not found
4433 ---------------------------------
4434 -- Generate_Discriminant_Check --
4435 ---------------------------------
4437 -- Note: the code for this procedure is derived from the
4438 -- Emit_Discriminant_Check Routine in trans.c.
4440 procedure Generate_Discriminant_Check (N : Node_Id) is
4441 Loc : constant Source_Ptr := Sloc (N);
4442 Pref : constant Node_Id := Prefix (N);
4443 Sel : constant Node_Id := Selector_Name (N);
4445 Orig_Comp : constant Entity_Id :=
4446 Original_Record_Component (Entity (Sel));
4447 -- The original component to be checked
4449 Discr_Fct : constant Entity_Id :=
4450 Discriminant_Checking_Func (Orig_Comp);
4451 -- The discriminant checking function
4454 -- One discriminant to be checked in the type
4456 Real_Discr : Entity_Id;
4457 -- Actual discriminant in the call
4459 Pref_Type : Entity_Id;
4460 -- Type of relevant prefix (ignoring private/access stuff)
4463 -- List of arguments for function call
4466 -- Keep track of the formal corresponding to the actual we build for
4467 -- each discriminant, in order to be able to perform the necessary type
4471 -- Selected component reference for checking function argument
4474 Pref_Type := Etype (Pref);
4476 -- Force evaluation of the prefix, so that it does not get evaluated
4477 -- twice (once for the check, once for the actual reference). Such a
4478 -- double evaluation is always a potential source of inefficiency,
4479 -- and is functionally incorrect in the volatile case, or when the
4480 -- prefix may have side-effects. An entity or a component of an
4481 -- entity requires no evaluation.
4483 if Is_Entity_Name (Pref) then
4484 if Treat_As_Volatile (Entity (Pref)) then
4485 Force_Evaluation (Pref, Name_Req => True);
4488 elsif Treat_As_Volatile (Etype (Pref)) then
4489 Force_Evaluation (Pref, Name_Req => True);
4491 elsif Nkind (Pref) = N_Selected_Component
4492 and then Is_Entity_Name (Prefix (Pref))
4497 Force_Evaluation (Pref, Name_Req => True);
4500 -- For a tagged type, use the scope of the original component to
4501 -- obtain the type, because ???
4503 if Is_Tagged_Type (Scope (Orig_Comp)) then
4504 Pref_Type := Scope (Orig_Comp);
4506 -- For an untagged derived type, use the discriminants of the parent
4507 -- which have been renamed in the derivation, possibly by a one-to-many
4508 -- discriminant constraint. For non-tagged type, initially get the Etype
4512 if Is_Derived_Type (Pref_Type)
4513 and then Number_Discriminants (Pref_Type) /=
4514 Number_Discriminants (Etype (Base_Type (Pref_Type)))
4516 Pref_Type := Etype (Base_Type (Pref_Type));
4520 -- We definitely should have a checking function, This routine should
4521 -- not be called if no discriminant checking function is present.
4523 pragma Assert (Present (Discr_Fct));
4525 -- Create the list of the actual parameters for the call. This list
4526 -- is the list of the discriminant fields of the record expression to
4527 -- be discriminant checked.
4530 Formal := First_Formal (Discr_Fct);
4531 Discr := First_Discriminant (Pref_Type);
4532 while Present (Discr) loop
4534 -- If we have a corresponding discriminant field, and a parent
4535 -- subtype is present, then we want to use the corresponding
4536 -- discriminant since this is the one with the useful value.
4538 if Present (Corresponding_Discriminant (Discr))
4539 and then Ekind (Pref_Type) = E_Record_Type
4540 and then Present (Parent_Subtype (Pref_Type))
4542 Real_Discr := Corresponding_Discriminant (Discr);
4544 Real_Discr := Discr;
4547 -- Construct the reference to the discriminant
4550 Make_Selected_Component (Loc,
4552 Unchecked_Convert_To (Pref_Type,
4553 Duplicate_Subexpr (Pref)),
4554 Selector_Name => New_Occurrence_Of (Real_Discr, Loc));
4556 -- Manually analyze and resolve this selected component. We really
4557 -- want it just as it appears above, and do not want the expander
4558 -- playing discriminal games etc with this reference. Then we append
4559 -- the argument to the list we are gathering.
4561 Set_Etype (Scomp, Etype (Real_Discr));
4562 Set_Analyzed (Scomp, True);
4563 Append_To (Args, Convert_To (Etype (Formal), Scomp));
4565 Next_Formal_With_Extras (Formal);
4566 Next_Discriminant (Discr);
4569 -- Now build and insert the call
4572 Make_Raise_Constraint_Error (Loc,
4574 Make_Function_Call (Loc,
4575 Name => New_Occurrence_Of (Discr_Fct, Loc),
4576 Parameter_Associations => Args),
4577 Reason => CE_Discriminant_Check_Failed));
4578 end Generate_Discriminant_Check;
4580 ---------------------------
4581 -- Generate_Index_Checks --
4582 ---------------------------
4584 procedure Generate_Index_Checks (N : Node_Id) is
4586 function Entity_Of_Prefix return Entity_Id;
4587 -- Returns the entity of the prefix of N (or Empty if not found)
4589 ----------------------
4590 -- Entity_Of_Prefix --
4591 ----------------------
4593 function Entity_Of_Prefix return Entity_Id is
4598 while not Is_Entity_Name (P) loop
4599 if not Nkind_In (P, N_Selected_Component,
4600 N_Indexed_Component)
4609 end Entity_Of_Prefix;
4613 Loc : constant Source_Ptr := Sloc (N);
4614 A : constant Node_Id := Prefix (N);
4615 A_Ent : constant Entity_Id := Entity_Of_Prefix;
4618 -- Start of processing for Generate_Index_Checks
4621 -- Ignore call if the prefix is not an array since we have a serious
4622 -- error in the sources. Ignore it also if index checks are suppressed
4623 -- for array object or type.
4625 if not Is_Array_Type (Etype (A))
4626 or else (Present (A_Ent)
4627 and then Index_Checks_Suppressed (A_Ent))
4628 or else Index_Checks_Suppressed (Etype (A))
4633 -- Generate a raise of constraint error with the appropriate reason and
4634 -- a condition of the form:
4636 -- Base_Type (Sub) not in Array'Range (Subscript)
4638 -- Note that the reason we generate the conversion to the base type here
4639 -- is that we definitely want the range check to take place, even if it
4640 -- looks like the subtype is OK. Optimization considerations that allow
4641 -- us to omit the check have already been taken into account in the
4642 -- setting of the Do_Range_Check flag earlier on.
4644 Sub := First (Expressions (N));
4646 -- Handle string literals
4648 if Ekind (Etype (A)) = E_String_Literal_Subtype then
4649 if Do_Range_Check (Sub) then
4650 Set_Do_Range_Check (Sub, False);
4652 -- For string literals we obtain the bounds of the string from the
4653 -- associated subtype.
4656 Make_Raise_Constraint_Error (Loc,
4660 Convert_To (Base_Type (Etype (Sub)),
4661 Duplicate_Subexpr_Move_Checks (Sub)),
4663 Make_Attribute_Reference (Loc,
4664 Prefix => New_Reference_To (Etype (A), Loc),
4665 Attribute_Name => Name_Range)),
4666 Reason => CE_Index_Check_Failed));
4673 A_Idx : Node_Id := Empty;
4680 A_Idx := First_Index (Etype (A));
4682 while Present (Sub) loop
4683 if Do_Range_Check (Sub) then
4684 Set_Do_Range_Check (Sub, False);
4686 -- Force evaluation except for the case of a simple name of
4687 -- a non-volatile entity.
4689 if not Is_Entity_Name (Sub)
4690 or else Treat_As_Volatile (Entity (Sub))
4692 Force_Evaluation (Sub);
4695 if Nkind (A_Idx) = N_Range then
4698 elsif Nkind (A_Idx) = N_Identifier
4699 or else Nkind (A_Idx) = N_Expanded_Name
4701 A_Range := Scalar_Range (Entity (A_Idx));
4703 else pragma Assert (Nkind (A_Idx) = N_Subtype_Indication);
4704 A_Range := Range_Expression (Constraint (A_Idx));
4707 -- For array objects with constant bounds we can generate
4708 -- the index check using the bounds of the type of the index
4711 and then Ekind (A_Ent) = E_Variable
4712 and then Is_Constant_Bound (Low_Bound (A_Range))
4713 and then Is_Constant_Bound (High_Bound (A_Range))
4716 Make_Attribute_Reference (Loc,
4718 New_Reference_To (Etype (A_Idx), Loc),
4719 Attribute_Name => Name_Range);
4721 -- For arrays with non-constant bounds we cannot generate
4722 -- the index check using the bounds of the type of the index
4723 -- since it may reference discriminants of some enclosing
4724 -- type. We obtain the bounds directly from the prefix
4731 Num := New_List (Make_Integer_Literal (Loc, Ind));
4735 Make_Attribute_Reference (Loc,
4737 Duplicate_Subexpr_Move_Checks (A, Name_Req => True),
4738 Attribute_Name => Name_Range,
4739 Expressions => Num);
4743 Make_Raise_Constraint_Error (Loc,
4747 Convert_To (Base_Type (Etype (Sub)),
4748 Duplicate_Subexpr_Move_Checks (Sub)),
4749 Right_Opnd => Range_N),
4750 Reason => CE_Index_Check_Failed));
4753 A_Idx := Next_Index (A_Idx);
4759 end Generate_Index_Checks;
4761 --------------------------
4762 -- Generate_Range_Check --
4763 --------------------------
4765 procedure Generate_Range_Check
4767 Target_Type : Entity_Id;
4768 Reason : RT_Exception_Code)
4770 Loc : constant Source_Ptr := Sloc (N);
4771 Source_Type : constant Entity_Id := Etype (N);
4772 Source_Base_Type : constant Entity_Id := Base_Type (Source_Type);
4773 Target_Base_Type : constant Entity_Id := Base_Type (Target_Type);
4776 -- First special case, if the source type is already within the range
4777 -- of the target type, then no check is needed (probably we should have
4778 -- stopped Do_Range_Check from being set in the first place, but better
4779 -- late than later in preventing junk code!
4781 -- We do NOT apply this if the source node is a literal, since in this
4782 -- case the literal has already been labeled as having the subtype of
4785 if In_Subrange_Of (Source_Type, Target_Type)
4787 (Nkind (N) = N_Integer_Literal
4789 Nkind (N) = N_Real_Literal
4791 Nkind (N) = N_Character_Literal
4794 and then Ekind (Entity (N)) = E_Enumeration_Literal))
4799 -- We need a check, so force evaluation of the node, so that it does
4800 -- not get evaluated twice (once for the check, once for the actual
4801 -- reference). Such a double evaluation is always a potential source
4802 -- of inefficiency, and is functionally incorrect in the volatile case.
4804 if not Is_Entity_Name (N)
4805 or else Treat_As_Volatile (Entity (N))
4807 Force_Evaluation (N);
4810 -- The easiest case is when Source_Base_Type and Target_Base_Type are
4811 -- the same since in this case we can simply do a direct check of the
4812 -- value of N against the bounds of Target_Type.
4814 -- [constraint_error when N not in Target_Type]
4816 -- Note: this is by far the most common case, for example all cases of
4817 -- checks on the RHS of assignments are in this category, but not all
4818 -- cases are like this. Notably conversions can involve two types.
4820 if Source_Base_Type = Target_Base_Type then
4822 Make_Raise_Constraint_Error (Loc,
4825 Left_Opnd => Duplicate_Subexpr (N),
4826 Right_Opnd => New_Occurrence_Of (Target_Type, Loc)),
4829 -- Next test for the case where the target type is within the bounds
4830 -- of the base type of the source type, since in this case we can
4831 -- simply convert these bounds to the base type of T to do the test.
4833 -- [constraint_error when N not in
4834 -- Source_Base_Type (Target_Type'First)
4836 -- Source_Base_Type(Target_Type'Last))]
4838 -- The conversions will always work and need no check
4840 -- Unchecked_Convert_To is used instead of Convert_To to handle the case
4841 -- of converting from an enumeration value to an integer type, such as
4842 -- occurs for the case of generating a range check on Enum'Val(Exp)
4843 -- (which used to be handled by gigi). This is OK, since the conversion
4844 -- itself does not require a check.
4846 elsif In_Subrange_Of (Target_Type, Source_Base_Type) then
4848 Make_Raise_Constraint_Error (Loc,
4851 Left_Opnd => Duplicate_Subexpr (N),
4856 Unchecked_Convert_To (Source_Base_Type,
4857 Make_Attribute_Reference (Loc,
4859 New_Occurrence_Of (Target_Type, Loc),
4860 Attribute_Name => Name_First)),
4863 Unchecked_Convert_To (Source_Base_Type,
4864 Make_Attribute_Reference (Loc,
4866 New_Occurrence_Of (Target_Type, Loc),
4867 Attribute_Name => Name_Last)))),
4870 -- Note that at this stage we now that the Target_Base_Type is not in
4871 -- the range of the Source_Base_Type (since even the Target_Type itself
4872 -- is not in this range). It could still be the case that Source_Type is
4873 -- in range of the target base type since we have not checked that case.
4875 -- If that is the case, we can freely convert the source to the target,
4876 -- and then test the target result against the bounds.
4878 elsif In_Subrange_Of (Source_Type, Target_Base_Type) then
4880 -- We make a temporary to hold the value of the converted value
4881 -- (converted to the base type), and then we will do the test against
4884 -- Tnn : constant Target_Base_Type := Target_Base_Type (N);
4885 -- [constraint_error when Tnn not in Target_Type]
4887 -- Then the conversion itself is replaced by an occurrence of Tnn
4890 Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N);
4893 Insert_Actions (N, New_List (
4894 Make_Object_Declaration (Loc,
4895 Defining_Identifier => Tnn,
4896 Object_Definition =>
4897 New_Occurrence_Of (Target_Base_Type, Loc),
4898 Constant_Present => True,
4900 Make_Type_Conversion (Loc,
4901 Subtype_Mark => New_Occurrence_Of (Target_Base_Type, Loc),
4902 Expression => Duplicate_Subexpr (N))),
4904 Make_Raise_Constraint_Error (Loc,
4907 Left_Opnd => New_Occurrence_Of (Tnn, Loc),
4908 Right_Opnd => New_Occurrence_Of (Target_Type, Loc)),
4910 Reason => Reason)));
4912 Rewrite (N, New_Occurrence_Of (Tnn, Loc));
4914 -- Set the type of N, because the declaration for Tnn might not
4915 -- be analyzed yet, as is the case if N appears within a record
4916 -- declaration, as a discriminant constraint or expression.
4918 Set_Etype (N, Target_Base_Type);
4921 -- At this stage, we know that we have two scalar types, which are
4922 -- directly convertible, and where neither scalar type has a base
4923 -- range that is in the range of the other scalar type.
4925 -- The only way this can happen is with a signed and unsigned type.
4926 -- So test for these two cases:
4929 -- Case of the source is unsigned and the target is signed
4931 if Is_Unsigned_Type (Source_Base_Type)
4932 and then not Is_Unsigned_Type (Target_Base_Type)
4934 -- If the source is unsigned and the target is signed, then we
4935 -- know that the source is not shorter than the target (otherwise
4936 -- the source base type would be in the target base type range).
4938 -- In other words, the unsigned type is either the same size as
4939 -- the target, or it is larger. It cannot be smaller.
4942 (Esize (Source_Base_Type) >= Esize (Target_Base_Type));
4944 -- We only need to check the low bound if the low bound of the
4945 -- target type is non-negative. If the low bound of the target
4946 -- type is negative, then we know that we will fit fine.
4948 -- If the high bound of the target type is negative, then we
4949 -- know we have a constraint error, since we can't possibly
4950 -- have a negative source.
4952 -- With these two checks out of the way, we can do the check
4953 -- using the source type safely
4955 -- This is definitely the most annoying case!
4957 -- [constraint_error
4958 -- when (Target_Type'First >= 0
4960 -- N < Source_Base_Type (Target_Type'First))
4961 -- or else Target_Type'Last < 0
4962 -- or else N > Source_Base_Type (Target_Type'Last)];
4964 -- We turn off all checks since we know that the conversions
4965 -- will work fine, given the guards for negative values.
4968 Make_Raise_Constraint_Error (Loc,
4974 Left_Opnd => Make_Op_Ge (Loc,
4976 Make_Attribute_Reference (Loc,
4978 New_Occurrence_Of (Target_Type, Loc),
4979 Attribute_Name => Name_First),
4980 Right_Opnd => Make_Integer_Literal (Loc, Uint_0)),
4984 Left_Opnd => Duplicate_Subexpr (N),
4986 Convert_To (Source_Base_Type,
4987 Make_Attribute_Reference (Loc,
4989 New_Occurrence_Of (Target_Type, Loc),
4990 Attribute_Name => Name_First)))),
4995 Make_Attribute_Reference (Loc,
4996 Prefix => New_Occurrence_Of (Target_Type, Loc),
4997 Attribute_Name => Name_Last),
4998 Right_Opnd => Make_Integer_Literal (Loc, Uint_0))),
5002 Left_Opnd => Duplicate_Subexpr (N),
5004 Convert_To (Source_Base_Type,
5005 Make_Attribute_Reference (Loc,
5006 Prefix => New_Occurrence_Of (Target_Type, Loc),
5007 Attribute_Name => Name_Last)))),
5010 Suppress => All_Checks);
5012 -- Only remaining possibility is that the source is signed and
5013 -- the target is unsigned.
5016 pragma Assert (not Is_Unsigned_Type (Source_Base_Type)
5017 and then Is_Unsigned_Type (Target_Base_Type));
5019 -- If the source is signed and the target is unsigned, then we
5020 -- know that the target is not shorter than the source (otherwise
5021 -- the target base type would be in the source base type range).
5023 -- In other words, the unsigned type is either the same size as
5024 -- the target, or it is larger. It cannot be smaller.
5026 -- Clearly we have an error if the source value is negative since
5027 -- no unsigned type can have negative values. If the source type
5028 -- is non-negative, then the check can be done using the target
5031 -- Tnn : constant Target_Base_Type (N) := Target_Type;
5033 -- [constraint_error
5034 -- when N < 0 or else Tnn not in Target_Type];
5036 -- We turn off all checks for the conversion of N to the target
5037 -- base type, since we generate the explicit check to ensure that
5038 -- the value is non-negative
5041 Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N);
5044 Insert_Actions (N, New_List (
5045 Make_Object_Declaration (Loc,
5046 Defining_Identifier => Tnn,
5047 Object_Definition =>
5048 New_Occurrence_Of (Target_Base_Type, Loc),
5049 Constant_Present => True,
5051 Make_Unchecked_Type_Conversion (Loc,
5053 New_Occurrence_Of (Target_Base_Type, Loc),
5054 Expression => Duplicate_Subexpr (N))),
5056 Make_Raise_Constraint_Error (Loc,
5061 Left_Opnd => Duplicate_Subexpr (N),
5062 Right_Opnd => Make_Integer_Literal (Loc, Uint_0)),
5066 Left_Opnd => New_Occurrence_Of (Tnn, Loc),
5068 New_Occurrence_Of (Target_Type, Loc))),
5071 Suppress => All_Checks);
5073 -- Set the Etype explicitly, because Insert_Actions may have
5074 -- placed the declaration in the freeze list for an enclosing
5075 -- construct, and thus it is not analyzed yet.
5077 Set_Etype (Tnn, Target_Base_Type);
5078 Rewrite (N, New_Occurrence_Of (Tnn, Loc));
5082 end Generate_Range_Check;
5088 function Get_Check_Id (N : Name_Id) return Check_Id is
5090 -- For standard check name, we can do a direct computation
5092 if N in First_Check_Name .. Last_Check_Name then
5093 return Check_Id (N - (First_Check_Name - 1));
5095 -- For non-standard names added by pragma Check_Name, search table
5098 for J in All_Checks + 1 .. Check_Names.Last loop
5099 if Check_Names.Table (J) = N then
5105 -- No matching name found
5110 ---------------------
5111 -- Get_Discriminal --
5112 ---------------------
5114 function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is
5115 Loc : constant Source_Ptr := Sloc (E);
5120 -- The bound can be a bona fide parameter of a protected operation,
5121 -- rather than a prival encoded as an in-parameter.
5123 if No (Discriminal_Link (Entity (Bound))) then
5127 -- Climb the scope stack looking for an enclosing protected type. If
5128 -- we run out of scopes, return the bound itself.
5131 while Present (Sc) loop
5132 if Sc = Standard_Standard then
5135 elsif Ekind (Sc) = E_Protected_Type then
5142 D := First_Discriminant (Sc);
5143 while Present (D) loop
5144 if Chars (D) = Chars (Bound) then
5145 return New_Occurrence_Of (Discriminal (D), Loc);
5148 Next_Discriminant (D);
5152 end Get_Discriminal;
5154 ----------------------
5155 -- Get_Range_Checks --
5156 ----------------------
5158 function Get_Range_Checks
5160 Target_Typ : Entity_Id;
5161 Source_Typ : Entity_Id := Empty;
5162 Warn_Node : Node_Id := Empty) return Check_Result
5165 return Selected_Range_Checks
5166 (Ck_Node, Target_Typ, Source_Typ, Warn_Node);
5167 end Get_Range_Checks;
5173 function Guard_Access
5176 Ck_Node : Node_Id) return Node_Id
5179 if Nkind (Cond) = N_Or_Else then
5180 Set_Paren_Count (Cond, 1);
5183 if Nkind (Ck_Node) = N_Allocator then
5190 Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
5191 Right_Opnd => Make_Null (Loc)),
5192 Right_Opnd => Cond);
5196 -----------------------------
5197 -- Index_Checks_Suppressed --
5198 -----------------------------
5200 function Index_Checks_Suppressed (E : Entity_Id) return Boolean is
5202 if Present (E) and then Checks_May_Be_Suppressed (E) then
5203 return Is_Check_Suppressed (E, Index_Check);
5205 return Scope_Suppress (Index_Check);
5207 end Index_Checks_Suppressed;
5213 procedure Initialize is
5215 for J in Determine_Range_Cache_N'Range loop
5216 Determine_Range_Cache_N (J) := Empty;
5221 for J in Int range 1 .. All_Checks loop
5222 Check_Names.Append (Name_Id (Int (First_Check_Name) + J - 1));
5226 -------------------------
5227 -- Insert_Range_Checks --
5228 -------------------------
5230 procedure Insert_Range_Checks
5231 (Checks : Check_Result;
5233 Suppress_Typ : Entity_Id;
5234 Static_Sloc : Source_Ptr := No_Location;
5235 Flag_Node : Node_Id := Empty;
5236 Do_Before : Boolean := False)
5238 Internal_Flag_Node : Node_Id := Flag_Node;
5239 Internal_Static_Sloc : Source_Ptr := Static_Sloc;
5241 Check_Node : Node_Id;
5242 Checks_On : constant Boolean :=
5243 (not Index_Checks_Suppressed (Suppress_Typ))
5245 (not Range_Checks_Suppressed (Suppress_Typ));
5248 -- For now we just return if Checks_On is false, however this should be
5249 -- enhanced to check for an always True value in the condition and to
5250 -- generate a compilation warning???
5252 if not Expander_Active or else not Checks_On then
5256 if Static_Sloc = No_Location then
5257 Internal_Static_Sloc := Sloc (Node);
5260 if No (Flag_Node) then
5261 Internal_Flag_Node := Node;
5264 for J in 1 .. 2 loop
5265 exit when No (Checks (J));
5267 if Nkind (Checks (J)) = N_Raise_Constraint_Error
5268 and then Present (Condition (Checks (J)))
5270 if not Has_Dynamic_Range_Check (Internal_Flag_Node) then
5271 Check_Node := Checks (J);
5272 Mark_Rewrite_Insertion (Check_Node);
5275 Insert_Before_And_Analyze (Node, Check_Node);
5277 Insert_After_And_Analyze (Node, Check_Node);
5280 Set_Has_Dynamic_Range_Check (Internal_Flag_Node);
5285 Make_Raise_Constraint_Error (Internal_Static_Sloc,
5286 Reason => CE_Range_Check_Failed);
5287 Mark_Rewrite_Insertion (Check_Node);
5290 Insert_Before_And_Analyze (Node, Check_Node);
5292 Insert_After_And_Analyze (Node, Check_Node);
5296 end Insert_Range_Checks;
5298 ------------------------
5299 -- Insert_Valid_Check --
5300 ------------------------
5302 procedure Insert_Valid_Check (Expr : Node_Id) is
5303 Loc : constant Source_Ptr := Sloc (Expr);
5307 -- Do not insert if checks off, or if not checking validity or
5308 -- if expression is known to be valid
5310 if not Validity_Checks_On
5311 or else Range_Or_Validity_Checks_Suppressed (Expr)
5312 or else Expr_Known_Valid (Expr)
5317 -- If we have a checked conversion, then validity check applies to
5318 -- the expression inside the conversion, not the result, since if
5319 -- the expression inside is valid, then so is the conversion result.
5322 while Nkind (Exp) = N_Type_Conversion loop
5323 Exp := Expression (Exp);
5326 -- We are about to insert the validity check for Exp. We save and
5327 -- reset the Do_Range_Check flag over this validity check, and then
5328 -- put it back for the final original reference (Exp may be rewritten).
5331 DRC : constant Boolean := Do_Range_Check (Exp);
5334 Set_Do_Range_Check (Exp, False);
5336 -- Force evaluation to avoid multiple reads for atomic/volatile
5338 if Is_Entity_Name (Exp)
5339 and then Is_Volatile (Entity (Exp))
5341 Force_Evaluation (Exp, Name_Req => True);
5344 -- Insert the validity check. Note that we do this with validity
5345 -- checks turned off, to avoid recursion, we do not want validity
5346 -- checks on the validity checking code itself!
5350 Make_Raise_Constraint_Error (Loc,
5354 Make_Attribute_Reference (Loc,
5356 Duplicate_Subexpr_No_Checks (Exp, Name_Req => True),
5357 Attribute_Name => Name_Valid)),
5358 Reason => CE_Invalid_Data),
5359 Suppress => Validity_Check);
5361 -- If the expression is a reference to an element of a bit-packed
5362 -- array, then it is rewritten as a renaming declaration. If the
5363 -- expression is an actual in a call, it has not been expanded,
5364 -- waiting for the proper point at which to do it. The same happens
5365 -- with renamings, so that we have to force the expansion now. This
5366 -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb
5369 if Is_Entity_Name (Exp)
5370 and then Nkind (Parent (Entity (Exp))) =
5371 N_Object_Renaming_Declaration
5374 Old_Exp : constant Node_Id := Name (Parent (Entity (Exp)));
5376 if Nkind (Old_Exp) = N_Indexed_Component
5377 and then Is_Bit_Packed_Array (Etype (Prefix (Old_Exp)))
5379 Expand_Packed_Element_Reference (Old_Exp);
5384 -- Put back the Do_Range_Check flag on the resulting (possibly
5385 -- rewritten) expression.
5387 -- Note: it might be thought that a validity check is not required
5388 -- when a range check is present, but that's not the case, because
5389 -- the back end is allowed to assume for the range check that the
5390 -- operand is within its declared range (an assumption that validity
5391 -- checking is all about NOT assuming!)
5393 -- Note: no need to worry about Possible_Local_Raise here, it will
5394 -- already have been called if original node has Do_Range_Check set.
5396 Set_Do_Range_Check (Exp, DRC);
5398 end Insert_Valid_Check;
5400 ----------------------------------
5401 -- Install_Null_Excluding_Check --
5402 ----------------------------------
5404 procedure Install_Null_Excluding_Check (N : Node_Id) is
5405 Loc : constant Source_Ptr := Sloc (Parent (N));
5406 Typ : constant Entity_Id := Etype (N);
5408 function Safe_To_Capture_In_Parameter_Value return Boolean;
5409 -- Determines if it is safe to capture Known_Non_Null status for an
5410 -- the entity referenced by node N. The caller ensures that N is indeed
5411 -- an entity name. It is safe to capture the non-null status for an IN
5412 -- parameter when the reference occurs within a declaration that is sure
5413 -- to be executed as part of the declarative region.
5415 procedure Mark_Non_Null;
5416 -- After installation of check, if the node in question is an entity
5417 -- name, then mark this entity as non-null if possible.
5419 function Safe_To_Capture_In_Parameter_Value return Boolean is
5420 E : constant Entity_Id := Entity (N);
5421 S : constant Entity_Id := Current_Scope;
5425 if Ekind (E) /= E_In_Parameter then
5429 -- Two initial context checks. We must be inside a subprogram body
5430 -- with declarations and reference must not appear in nested scopes.
5432 if (Ekind (S) /= E_Function and then Ekind (S) /= E_Procedure)
5433 or else Scope (E) /= S
5438 S_Par := Parent (Parent (S));
5440 if Nkind (S_Par) /= N_Subprogram_Body
5441 or else No (Declarations (S_Par))
5451 -- Retrieve the declaration node of N (if any). Note that N
5452 -- may be a part of a complex initialization expression.
5456 while Present (P) loop
5458 -- If we have a short circuit form, and we are within the right
5459 -- hand expression, we return false, since the right hand side
5460 -- is not guaranteed to be elaborated.
5462 if Nkind (P) in N_Short_Circuit
5463 and then N = Right_Opnd (P)
5468 -- Similarly, if we are in a conditional expression and not
5469 -- part of the condition, then we return False, since neither
5470 -- the THEN or ELSE expressions will always be elaborated.
5472 if Nkind (P) = N_Conditional_Expression
5473 and then N /= First (Expressions (P))
5478 -- If we are in a case expression, and not part of the
5479 -- expression, then we return False, since a particular
5480 -- branch may not always be elaborated
5482 if Nkind (P) = N_Case_Expression
5483 and then N /= Expression (P)
5488 -- While traversing the parent chain, we find that N
5489 -- belongs to a statement, thus it may never appear in
5490 -- a declarative region.
5492 if Nkind (P) in N_Statement_Other_Than_Procedure_Call
5493 or else Nkind (P) = N_Procedure_Call_Statement
5498 -- If we are at a declaration, record it and exit
5500 if Nkind (P) in N_Declaration
5501 and then Nkind (P) not in N_Subprogram_Specification
5514 return List_Containing (N_Decl) = Declarations (S_Par);
5516 end Safe_To_Capture_In_Parameter_Value;
5522 procedure Mark_Non_Null is
5524 -- Only case of interest is if node N is an entity name
5526 if Is_Entity_Name (N) then
5528 -- For sure, we want to clear an indication that this is known to
5529 -- be null, since if we get past this check, it definitely is not!
5531 Set_Is_Known_Null (Entity (N), False);
5533 -- We can mark the entity as known to be non-null if either it is
5534 -- safe to capture the value, or in the case of an IN parameter,
5535 -- which is a constant, if the check we just installed is in the
5536 -- declarative region of the subprogram body. In this latter case,
5537 -- a check is decisive for the rest of the body if the expression
5538 -- is sure to be elaborated, since we know we have to elaborate
5539 -- all declarations before executing the body.
5541 -- Couldn't this always be part of Safe_To_Capture_Value ???
5543 if Safe_To_Capture_Value (N, Entity (N))
5544 or else Safe_To_Capture_In_Parameter_Value
5546 Set_Is_Known_Non_Null (Entity (N));
5551 -- Start of processing for Install_Null_Excluding_Check
5554 pragma Assert (Is_Access_Type (Typ));
5556 -- No check inside a generic (why not???)
5558 if Inside_A_Generic then
5562 -- No check needed if known to be non-null
5564 if Known_Non_Null (N) then
5568 -- If known to be null, here is where we generate a compile time check
5570 if Known_Null (N) then
5572 -- Avoid generating warning message inside init procs
5574 if not Inside_Init_Proc then
5575 Apply_Compile_Time_Constraint_Error
5577 "null value not allowed here?",
5578 CE_Access_Check_Failed);
5581 Make_Raise_Constraint_Error (Loc,
5582 Reason => CE_Access_Check_Failed));
5589 -- If entity is never assigned, for sure a warning is appropriate
5591 if Is_Entity_Name (N) then
5592 Check_Unset_Reference (N);
5595 -- No check needed if checks are suppressed on the range. Note that we
5596 -- don't set Is_Known_Non_Null in this case (we could legitimately do
5597 -- so, since the program is erroneous, but we don't like to casually
5598 -- propagate such conclusions from erroneosity).
5600 if Access_Checks_Suppressed (Typ) then
5604 -- No check needed for access to concurrent record types generated by
5605 -- the expander. This is not just an optimization (though it does indeed
5606 -- remove junk checks). It also avoids generation of junk warnings.
5608 if Nkind (N) in N_Has_Chars
5609 and then Chars (N) = Name_uObject
5610 and then Is_Concurrent_Record_Type
5611 (Directly_Designated_Type (Etype (N)))
5616 -- Otherwise install access check
5619 Make_Raise_Constraint_Error (Loc,
5622 Left_Opnd => Duplicate_Subexpr_Move_Checks (N),
5623 Right_Opnd => Make_Null (Loc)),
5624 Reason => CE_Access_Check_Failed));
5627 end Install_Null_Excluding_Check;
5629 --------------------------
5630 -- Install_Static_Check --
5631 --------------------------
5633 procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is
5634 Stat : constant Boolean := Is_Static_Expression (R_Cno);
5635 Typ : constant Entity_Id := Etype (R_Cno);
5639 Make_Raise_Constraint_Error (Loc,
5640 Reason => CE_Range_Check_Failed));
5641 Set_Analyzed (R_Cno);
5642 Set_Etype (R_Cno, Typ);
5643 Set_Raises_Constraint_Error (R_Cno);
5644 Set_Is_Static_Expression (R_Cno, Stat);
5646 -- Now deal with possible local raise handling
5648 Possible_Local_Raise (R_Cno, Standard_Constraint_Error);
5649 end Install_Static_Check;
5651 ---------------------
5652 -- Kill_All_Checks --
5653 ---------------------
5655 procedure Kill_All_Checks is
5657 if Debug_Flag_CC then
5658 w ("Kill_All_Checks");
5661 -- We reset the number of saved checks to zero, and also modify all
5662 -- stack entries for statement ranges to indicate that the number of
5663 -- checks at each level is now zero.
5665 Num_Saved_Checks := 0;
5667 -- Note: the Int'Min here avoids any possibility of J being out of
5668 -- range when called from e.g. Conditional_Statements_Begin.
5670 for J in 1 .. Int'Min (Saved_Checks_TOS, Saved_Checks_Stack'Last) loop
5671 Saved_Checks_Stack (J) := 0;
5673 end Kill_All_Checks;
5679 procedure Kill_Checks (V : Entity_Id) is
5681 if Debug_Flag_CC then
5682 w ("Kill_Checks for entity", Int (V));
5685 for J in 1 .. Num_Saved_Checks loop
5686 if Saved_Checks (J).Entity = V then
5687 if Debug_Flag_CC then
5688 w (" Checks killed for saved check ", J);
5691 Saved_Checks (J).Killed := True;
5696 ------------------------------
5697 -- Length_Checks_Suppressed --
5698 ------------------------------
5700 function Length_Checks_Suppressed (E : Entity_Id) return Boolean is
5702 if Present (E) and then Checks_May_Be_Suppressed (E) then
5703 return Is_Check_Suppressed (E, Length_Check);
5705 return Scope_Suppress (Length_Check);
5707 end Length_Checks_Suppressed;
5709 --------------------------------
5710 -- Overflow_Checks_Suppressed --
5711 --------------------------------
5713 function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is
5715 if Present (E) and then Checks_May_Be_Suppressed (E) then
5716 return Is_Check_Suppressed (E, Overflow_Check);
5718 return Scope_Suppress (Overflow_Check);
5720 end Overflow_Checks_Suppressed;
5722 -----------------------------
5723 -- Range_Checks_Suppressed --
5724 -----------------------------
5726 function Range_Checks_Suppressed (E : Entity_Id) return Boolean is
5730 -- Note: for now we always suppress range checks on Vax float types,
5731 -- since Gigi does not know how to generate these checks.
5733 if Vax_Float (E) then
5735 elsif Kill_Range_Checks (E) then
5737 elsif Checks_May_Be_Suppressed (E) then
5738 return Is_Check_Suppressed (E, Range_Check);
5742 return Scope_Suppress (Range_Check);
5743 end Range_Checks_Suppressed;
5745 -----------------------------------------
5746 -- Range_Or_Validity_Checks_Suppressed --
5747 -----------------------------------------
5749 -- Note: the coding would be simpler here if we simply made appropriate
5750 -- calls to Range/Validity_Checks_Suppressed, but that would result in
5751 -- duplicated checks which we prefer to avoid.
5753 function Range_Or_Validity_Checks_Suppressed
5754 (Expr : Node_Id) return Boolean
5757 -- Immediate return if scope checks suppressed for either check
5759 if Scope_Suppress (Range_Check) or Scope_Suppress (Validity_Check) then
5763 -- If no expression, that's odd, decide that checks are suppressed,
5764 -- since we don't want anyone trying to do checks in this case, which
5765 -- is most likely the result of some other error.
5771 -- Expression is present, so perform suppress checks on type
5774 Typ : constant Entity_Id := Etype (Expr);
5776 if Vax_Float (Typ) then
5778 elsif Checks_May_Be_Suppressed (Typ)
5779 and then (Is_Check_Suppressed (Typ, Range_Check)
5781 Is_Check_Suppressed (Typ, Validity_Check))
5787 -- If expression is an entity name, perform checks on this entity
5789 if Is_Entity_Name (Expr) then
5791 Ent : constant Entity_Id := Entity (Expr);
5793 if Checks_May_Be_Suppressed (Ent) then
5794 return Is_Check_Suppressed (Ent, Range_Check)
5795 or else Is_Check_Suppressed (Ent, Validity_Check);
5800 -- If we fall through, no checks suppressed
5803 end Range_Or_Validity_Checks_Suppressed;
5809 procedure Remove_Checks (Expr : Node_Id) is
5810 function Process (N : Node_Id) return Traverse_Result;
5811 -- Process a single node during the traversal
5813 procedure Traverse is new Traverse_Proc (Process);
5814 -- The traversal procedure itself
5820 function Process (N : Node_Id) return Traverse_Result is
5822 if Nkind (N) not in N_Subexpr then
5826 Set_Do_Range_Check (N, False);
5830 Traverse (Left_Opnd (N));
5833 when N_Attribute_Reference =>
5834 Set_Do_Overflow_Check (N, False);
5836 when N_Function_Call =>
5837 Set_Do_Tag_Check (N, False);
5840 Set_Do_Overflow_Check (N, False);
5844 Set_Do_Division_Check (N, False);
5847 Set_Do_Length_Check (N, False);
5850 Set_Do_Division_Check (N, False);
5853 Set_Do_Length_Check (N, False);
5856 Set_Do_Division_Check (N, False);
5859 Set_Do_Length_Check (N, False);
5866 Traverse (Left_Opnd (N));
5869 when N_Selected_Component =>
5870 Set_Do_Discriminant_Check (N, False);
5872 when N_Type_Conversion =>
5873 Set_Do_Length_Check (N, False);
5874 Set_Do_Tag_Check (N, False);
5875 Set_Do_Overflow_Check (N, False);
5884 -- Start of processing for Remove_Checks
5890 ----------------------------
5891 -- Selected_Length_Checks --
5892 ----------------------------
5894 function Selected_Length_Checks
5896 Target_Typ : Entity_Id;
5897 Source_Typ : Entity_Id;
5898 Warn_Node : Node_Id) return Check_Result
5900 Loc : constant Source_Ptr := Sloc (Ck_Node);
5903 Expr_Actual : Node_Id;
5905 Cond : Node_Id := Empty;
5906 Do_Access : Boolean := False;
5907 Wnode : Node_Id := Warn_Node;
5908 Ret_Result : Check_Result := (Empty, Empty);
5909 Num_Checks : Natural := 0;
5911 procedure Add_Check (N : Node_Id);
5912 -- Adds the action given to Ret_Result if N is non-Empty
5914 function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id;
5915 function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id;
5916 -- Comments required ???
5918 function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean;
5919 -- True for equal literals and for nodes that denote the same constant
5920 -- entity, even if its value is not a static constant. This includes the
5921 -- case of a discriminal reference within an init proc. Removes some
5922 -- obviously superfluous checks.
5924 function Length_E_Cond
5925 (Exptyp : Entity_Id;
5927 Indx : Nat) return Node_Id;
5928 -- Returns expression to compute:
5929 -- Typ'Length /= Exptyp'Length
5931 function Length_N_Cond
5934 Indx : Nat) return Node_Id;
5935 -- Returns expression to compute:
5936 -- Typ'Length /= Expr'Length
5942 procedure Add_Check (N : Node_Id) is
5946 -- For now, ignore attempt to place more than 2 checks ???
5948 if Num_Checks = 2 then
5952 pragma Assert (Num_Checks <= 1);
5953 Num_Checks := Num_Checks + 1;
5954 Ret_Result (Num_Checks) := N;
5962 function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is
5963 SE : constant Entity_Id := Scope (E);
5965 E1 : Entity_Id := E;
5968 if Ekind (Scope (E)) = E_Record_Type
5969 and then Has_Discriminants (Scope (E))
5971 N := Build_Discriminal_Subtype_Of_Component (E);
5974 Insert_Action (Ck_Node, N);
5975 E1 := Defining_Identifier (N);
5979 if Ekind (E1) = E_String_Literal_Subtype then
5981 Make_Integer_Literal (Loc,
5982 Intval => String_Literal_Length (E1));
5984 elsif SE /= Standard_Standard
5985 and then Ekind (Scope (SE)) = E_Protected_Type
5986 and then Has_Discriminants (Scope (SE))
5987 and then Has_Completion (Scope (SE))
5988 and then not Inside_Init_Proc
5990 -- If the type whose length is needed is a private component
5991 -- constrained by a discriminant, we must expand the 'Length
5992 -- attribute into an explicit computation, using the discriminal
5993 -- of the current protected operation. This is because the actual
5994 -- type of the prival is constructed after the protected opera-
5995 -- tion has been fully expanded.
5998 Indx_Type : Node_Id;
6001 Do_Expand : Boolean := False;
6004 Indx_Type := First_Index (E);
6006 for J in 1 .. Indx - 1 loop
6007 Next_Index (Indx_Type);
6010 Get_Index_Bounds (Indx_Type, Lo, Hi);
6012 if Nkind (Lo) = N_Identifier
6013 and then Ekind (Entity (Lo)) = E_In_Parameter
6015 Lo := Get_Discriminal (E, Lo);
6019 if Nkind (Hi) = N_Identifier
6020 and then Ekind (Entity (Hi)) = E_In_Parameter
6022 Hi := Get_Discriminal (E, Hi);
6027 if not Is_Entity_Name (Lo) then
6028 Lo := Duplicate_Subexpr_No_Checks (Lo);
6031 if not Is_Entity_Name (Hi) then
6032 Lo := Duplicate_Subexpr_No_Checks (Hi);
6038 Make_Op_Subtract (Loc,
6042 Right_Opnd => Make_Integer_Literal (Loc, 1));
6047 Make_Attribute_Reference (Loc,
6048 Attribute_Name => Name_Length,
6050 New_Occurrence_Of (E1, Loc));
6053 Set_Expressions (N, New_List (
6054 Make_Integer_Literal (Loc, Indx)));
6063 Make_Attribute_Reference (Loc,
6064 Attribute_Name => Name_Length,
6066 New_Occurrence_Of (E1, Loc));
6069 Set_Expressions (N, New_List (
6070 Make_Integer_Literal (Loc, Indx)));
6081 function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is
6084 Make_Attribute_Reference (Loc,
6085 Attribute_Name => Name_Length,
6087 Duplicate_Subexpr_No_Checks (N, Name_Req => True),
6088 Expressions => New_List (
6089 Make_Integer_Literal (Loc, Indx)));
6096 function Length_E_Cond
6097 (Exptyp : Entity_Id;
6099 Indx : Nat) return Node_Id
6104 Left_Opnd => Get_E_Length (Typ, Indx),
6105 Right_Opnd => Get_E_Length (Exptyp, Indx));
6112 function Length_N_Cond
6115 Indx : Nat) return Node_Id
6120 Left_Opnd => Get_E_Length (Typ, Indx),
6121 Right_Opnd => Get_N_Length (Expr, Indx));
6128 function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is
6131 (Nkind (L) = N_Integer_Literal
6132 and then Nkind (R) = N_Integer_Literal
6133 and then Intval (L) = Intval (R))
6137 and then Ekind (Entity (L)) = E_Constant
6138 and then ((Is_Entity_Name (R)
6139 and then Entity (L) = Entity (R))
6141 (Nkind (R) = N_Type_Conversion
6142 and then Is_Entity_Name (Expression (R))
6143 and then Entity (L) = Entity (Expression (R)))))
6147 and then Ekind (Entity (R)) = E_Constant
6148 and then Nkind (L) = N_Type_Conversion
6149 and then Is_Entity_Name (Expression (L))
6150 and then Entity (R) = Entity (Expression (L)))
6154 and then Is_Entity_Name (R)
6155 and then Entity (L) = Entity (R)
6156 and then Ekind (Entity (L)) = E_In_Parameter
6157 and then Inside_Init_Proc);
6160 -- Start of processing for Selected_Length_Checks
6163 if not Expander_Active then
6167 if Target_Typ = Any_Type
6168 or else Target_Typ = Any_Composite
6169 or else Raises_Constraint_Error (Ck_Node)
6178 T_Typ := Target_Typ;
6180 if No (Source_Typ) then
6181 S_Typ := Etype (Ck_Node);
6183 S_Typ := Source_Typ;
6186 if S_Typ = Any_Type or else S_Typ = Any_Composite then
6190 if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then
6191 S_Typ := Designated_Type (S_Typ);
6192 T_Typ := Designated_Type (T_Typ);
6195 -- A simple optimization for the null case
6197 if Known_Null (Ck_Node) then
6202 if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then
6203 if Is_Constrained (T_Typ) then
6205 -- The checking code to be generated will freeze the
6206 -- corresponding array type. However, we must freeze the
6207 -- type now, so that the freeze node does not appear within
6208 -- the generated conditional expression, but ahead of it.
6210 Freeze_Before (Ck_Node, T_Typ);
6212 Expr_Actual := Get_Referenced_Object (Ck_Node);
6213 Exptyp := Get_Actual_Subtype (Ck_Node);
6215 if Is_Access_Type (Exptyp) then
6216 Exptyp := Designated_Type (Exptyp);
6219 -- String_Literal case. This needs to be handled specially be-
6220 -- cause no index types are available for string literals. The
6221 -- condition is simply:
6223 -- T_Typ'Length = string-literal-length
6225 if Nkind (Expr_Actual) = N_String_Literal
6226 and then Ekind (Etype (Expr_Actual)) = E_String_Literal_Subtype
6230 Left_Opnd => Get_E_Length (T_Typ, 1),
6232 Make_Integer_Literal (Loc,
6234 String_Literal_Length (Etype (Expr_Actual))));
6236 -- General array case. Here we have a usable actual subtype for
6237 -- the expression, and the condition is built from the two types
6240 -- T_Typ'Length /= Exptyp'Length or else
6241 -- T_Typ'Length (2) /= Exptyp'Length (2) or else
6242 -- T_Typ'Length (3) /= Exptyp'Length (3) or else
6245 elsif Is_Constrained (Exptyp) then
6247 Ndims : constant Nat := Number_Dimensions (T_Typ);
6260 -- At the library level, we need to ensure that the type of
6261 -- the object is elaborated before the check itself is
6262 -- emitted. This is only done if the object is in the
6263 -- current compilation unit, otherwise the type is frozen
6264 -- and elaborated in its unit.
6266 if Is_Itype (Exptyp)
6268 Ekind (Cunit_Entity (Current_Sem_Unit)) = E_Package
6270 not In_Package_Body (Cunit_Entity (Current_Sem_Unit))
6271 and then In_Open_Scopes (Scope (Exptyp))
6273 Ref_Node := Make_Itype_Reference (Sloc (Ck_Node));
6274 Set_Itype (Ref_Node, Exptyp);
6275 Insert_Action (Ck_Node, Ref_Node);
6278 L_Index := First_Index (T_Typ);
6279 R_Index := First_Index (Exptyp);
6281 for Indx in 1 .. Ndims loop
6282 if not (Nkind (L_Index) = N_Raise_Constraint_Error
6284 Nkind (R_Index) = N_Raise_Constraint_Error)
6286 Get_Index_Bounds (L_Index, L_Low, L_High);
6287 Get_Index_Bounds (R_Index, R_Low, R_High);
6289 -- Deal with compile time length check. Note that we
6290 -- skip this in the access case, because the access
6291 -- value may be null, so we cannot know statically.
6294 and then Compile_Time_Known_Value (L_Low)
6295 and then Compile_Time_Known_Value (L_High)
6296 and then Compile_Time_Known_Value (R_Low)
6297 and then Compile_Time_Known_Value (R_High)
6299 if Expr_Value (L_High) >= Expr_Value (L_Low) then
6300 L_Length := Expr_Value (L_High) -
6301 Expr_Value (L_Low) + 1;
6303 L_Length := UI_From_Int (0);
6306 if Expr_Value (R_High) >= Expr_Value (R_Low) then
6307 R_Length := Expr_Value (R_High) -
6308 Expr_Value (R_Low) + 1;
6310 R_Length := UI_From_Int (0);
6313 if L_Length > R_Length then
6315 (Compile_Time_Constraint_Error
6316 (Wnode, "too few elements for}?", T_Typ));
6318 elsif L_Length < R_Length then
6320 (Compile_Time_Constraint_Error
6321 (Wnode, "too many elements for}?", T_Typ));
6324 -- The comparison for an individual index subtype
6325 -- is omitted if the corresponding index subtypes
6326 -- statically match, since the result is known to
6327 -- be true. Note that this test is worth while even
6328 -- though we do static evaluation, because non-static
6329 -- subtypes can statically match.
6332 Subtypes_Statically_Match
6333 (Etype (L_Index), Etype (R_Index))
6336 (Same_Bounds (L_Low, R_Low)
6337 and then Same_Bounds (L_High, R_High))
6340 (Cond, Length_E_Cond (Exptyp, T_Typ, Indx));
6349 -- Handle cases where we do not get a usable actual subtype that
6350 -- is constrained. This happens for example in the function call
6351 -- and explicit dereference cases. In these cases, we have to get
6352 -- the length or range from the expression itself, making sure we
6353 -- do not evaluate it more than once.
6355 -- Here Ck_Node is the original expression, or more properly the
6356 -- result of applying Duplicate_Expr to the original tree, forcing
6357 -- the result to be a name.
6361 Ndims : constant Nat := Number_Dimensions (T_Typ);
6364 -- Build the condition for the explicit dereference case
6366 for Indx in 1 .. Ndims loop
6368 (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx));
6375 -- Construct the test and insert into the tree
6377 if Present (Cond) then
6379 Cond := Guard_Access (Cond, Loc, Ck_Node);
6383 (Make_Raise_Constraint_Error (Loc,
6385 Reason => CE_Length_Check_Failed));
6389 end Selected_Length_Checks;
6391 ---------------------------
6392 -- Selected_Range_Checks --
6393 ---------------------------
6395 function Selected_Range_Checks
6397 Target_Typ : Entity_Id;
6398 Source_Typ : Entity_Id;
6399 Warn_Node : Node_Id) return Check_Result
6401 Loc : constant Source_Ptr := Sloc (Ck_Node);
6404 Expr_Actual : Node_Id;
6406 Cond : Node_Id := Empty;
6407 Do_Access : Boolean := False;
6408 Wnode : Node_Id := Warn_Node;
6409 Ret_Result : Check_Result := (Empty, Empty);
6410 Num_Checks : Integer := 0;
6412 procedure Add_Check (N : Node_Id);
6413 -- Adds the action given to Ret_Result if N is non-Empty
6415 function Discrete_Range_Cond
6417 Typ : Entity_Id) return Node_Id;
6418 -- Returns expression to compute:
6419 -- Low_Bound (Expr) < Typ'First
6421 -- High_Bound (Expr) > Typ'Last
6423 function Discrete_Expr_Cond
6425 Typ : Entity_Id) return Node_Id;
6426 -- Returns expression to compute:
6431 function Get_E_First_Or_Last
6435 Nam : Name_Id) return Node_Id;
6436 -- Returns an attribute reference
6437 -- E'First or E'Last
6438 -- with a source location of Loc.
6440 -- Nam is Name_First or Name_Last, according to which attribute is
6441 -- desired. If Indx is non-zero, it is passed as a literal in the
6442 -- Expressions of the attribute reference (identifying the desired
6443 -- array dimension).
6445 function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id;
6446 function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id;
6447 -- Returns expression to compute:
6448 -- N'First or N'Last using Duplicate_Subexpr_No_Checks
6450 function Range_E_Cond
6451 (Exptyp : Entity_Id;
6455 -- Returns expression to compute:
6456 -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
6458 function Range_Equal_E_Cond
6459 (Exptyp : Entity_Id;
6461 Indx : Nat) return Node_Id;
6462 -- Returns expression to compute:
6463 -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
6465 function Range_N_Cond
6468 Indx : Nat) return Node_Id;
6469 -- Return expression to compute:
6470 -- Expr'First < Typ'First or else Expr'Last > Typ'Last
6476 procedure Add_Check (N : Node_Id) is
6480 -- For now, ignore attempt to place more than 2 checks ???
6482 if Num_Checks = 2 then
6486 pragma Assert (Num_Checks <= 1);
6487 Num_Checks := Num_Checks + 1;
6488 Ret_Result (Num_Checks) := N;
6492 -------------------------
6493 -- Discrete_Expr_Cond --
6494 -------------------------
6496 function Discrete_Expr_Cond
6498 Typ : Entity_Id) return Node_Id
6506 Convert_To (Base_Type (Typ),
6507 Duplicate_Subexpr_No_Checks (Expr)),
6509 Convert_To (Base_Type (Typ),
6510 Get_E_First_Or_Last (Loc, Typ, 0, Name_First))),
6515 Convert_To (Base_Type (Typ),
6516 Duplicate_Subexpr_No_Checks (Expr)),
6520 Get_E_First_Or_Last (Loc, Typ, 0, Name_Last))));
6521 end Discrete_Expr_Cond;
6523 -------------------------
6524 -- Discrete_Range_Cond --
6525 -------------------------
6527 function Discrete_Range_Cond
6529 Typ : Entity_Id) return Node_Id
6531 LB : Node_Id := Low_Bound (Expr);
6532 HB : Node_Id := High_Bound (Expr);
6534 Left_Opnd : Node_Id;
6535 Right_Opnd : Node_Id;
6538 if Nkind (LB) = N_Identifier
6539 and then Ekind (Entity (LB)) = E_Discriminant
6541 LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc);
6544 if Nkind (HB) = N_Identifier
6545 and then Ekind (Entity (HB)) = E_Discriminant
6547 HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc);
6554 (Base_Type (Typ), Duplicate_Subexpr_No_Checks (LB)),
6559 Get_E_First_Or_Last (Loc, Typ, 0, Name_First)));
6561 if Base_Type (Typ) = Typ then
6564 elsif Compile_Time_Known_Value (High_Bound (Scalar_Range (Typ)))
6566 Compile_Time_Known_Value (High_Bound (Scalar_Range
6569 if Is_Floating_Point_Type (Typ) then
6570 if Expr_Value_R (High_Bound (Scalar_Range (Typ))) =
6571 Expr_Value_R (High_Bound (Scalar_Range (Base_Type (Typ))))
6577 if Expr_Value (High_Bound (Scalar_Range (Typ))) =
6578 Expr_Value (High_Bound (Scalar_Range (Base_Type (Typ))))
6589 (Base_Type (Typ), Duplicate_Subexpr_No_Checks (HB)),
6594 Get_E_First_Or_Last (Loc, Typ, 0, Name_Last)));
6596 return Make_Or_Else (Loc, Left_Opnd, Right_Opnd);
6597 end Discrete_Range_Cond;
6599 -------------------------
6600 -- Get_E_First_Or_Last --
6601 -------------------------
6603 function Get_E_First_Or_Last
6607 Nam : Name_Id) return Node_Id
6612 Exprs := New_List (Make_Integer_Literal (Loc, UI_From_Int (Indx)));
6617 return Make_Attribute_Reference (Loc,
6618 Prefix => New_Occurrence_Of (E, Loc),
6619 Attribute_Name => Nam,
6620 Expressions => Exprs);
6621 end Get_E_First_Or_Last;
6627 function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is
6630 Make_Attribute_Reference (Loc,
6631 Attribute_Name => Name_First,
6633 Duplicate_Subexpr_No_Checks (N, Name_Req => True),
6634 Expressions => New_List (
6635 Make_Integer_Literal (Loc, Indx)));
6642 function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is
6645 Make_Attribute_Reference (Loc,
6646 Attribute_Name => Name_Last,
6648 Duplicate_Subexpr_No_Checks (N, Name_Req => True),
6649 Expressions => New_List (
6650 Make_Integer_Literal (Loc, Indx)));
6657 function Range_E_Cond
6658 (Exptyp : Entity_Id;
6660 Indx : Nat) return Node_Id
6668 Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First),
6670 Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)),
6675 Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last),
6677 Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last)));
6680 ------------------------
6681 -- Range_Equal_E_Cond --
6682 ------------------------
6684 function Range_Equal_E_Cond
6685 (Exptyp : Entity_Id;
6687 Indx : Nat) return Node_Id
6695 Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First),
6697 Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)),
6702 Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last),
6704 Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last)));
6705 end Range_Equal_E_Cond;
6711 function Range_N_Cond
6714 Indx : Nat) return Node_Id
6722 Get_N_First (Expr, Indx),
6724 Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)),
6729 Get_N_Last (Expr, Indx),
6731 Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last)));
6734 -- Start of processing for Selected_Range_Checks
6737 if not Expander_Active then
6741 if Target_Typ = Any_Type
6742 or else Target_Typ = Any_Composite
6743 or else Raises_Constraint_Error (Ck_Node)
6752 T_Typ := Target_Typ;
6754 if No (Source_Typ) then
6755 S_Typ := Etype (Ck_Node);
6757 S_Typ := Source_Typ;
6760 if S_Typ = Any_Type or else S_Typ = Any_Composite then
6764 -- The order of evaluating T_Typ before S_Typ seems to be critical
6765 -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
6766 -- in, and since Node can be an N_Range node, it might be invalid.
6767 -- Should there be an assert check somewhere for taking the Etype of
6768 -- an N_Range node ???
6770 if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then
6771 S_Typ := Designated_Type (S_Typ);
6772 T_Typ := Designated_Type (T_Typ);
6775 -- A simple optimization for the null case
6777 if Known_Null (Ck_Node) then
6782 -- For an N_Range Node, check for a null range and then if not
6783 -- null generate a range check action.
6785 if Nkind (Ck_Node) = N_Range then
6787 -- There's no point in checking a range against itself
6789 if Ck_Node = Scalar_Range (T_Typ) then
6794 T_LB : constant Node_Id := Type_Low_Bound (T_Typ);
6795 T_HB : constant Node_Id := Type_High_Bound (T_Typ);
6796 Known_T_LB : constant Boolean := Compile_Time_Known_Value (T_LB);
6797 Known_T_HB : constant Boolean := Compile_Time_Known_Value (T_HB);
6799 LB : Node_Id := Low_Bound (Ck_Node);
6800 HB : Node_Id := High_Bound (Ck_Node);
6804 Null_Range : Boolean;
6805 Out_Of_Range_L : Boolean;
6806 Out_Of_Range_H : Boolean;
6809 -- Compute what is known at compile time
6811 if Known_T_LB and Known_T_HB then
6812 if Compile_Time_Known_Value (LB) then
6815 -- There's no point in checking that a bound is within its
6816 -- own range so pretend that it is known in this case. First
6817 -- deal with low bound.
6819 elsif Ekind (Etype (LB)) = E_Signed_Integer_Subtype
6820 and then Scalar_Range (Etype (LB)) = Scalar_Range (T_Typ)
6829 -- Likewise for the high bound
6831 if Compile_Time_Known_Value (HB) then
6834 elsif Ekind (Etype (HB)) = E_Signed_Integer_Subtype
6835 and then Scalar_Range (Etype (HB)) = Scalar_Range (T_Typ)
6845 -- Check for case where everything is static and we can do the
6846 -- check at compile time. This is skipped if we have an access
6847 -- type, since the access value may be null.
6849 -- ??? This code can be improved since you only need to know that
6850 -- the two respective bounds (LB & T_LB or HB & T_HB) are known at
6851 -- compile time to emit pertinent messages.
6853 if Known_T_LB and Known_T_HB and Known_LB and Known_HB
6856 -- Floating-point case
6858 if Is_Floating_Point_Type (S_Typ) then
6859 Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB);
6861 (Expr_Value_R (LB) < Expr_Value_R (T_LB))
6863 (Expr_Value_R (LB) > Expr_Value_R (T_HB));
6866 (Expr_Value_R (HB) > Expr_Value_R (T_HB))
6868 (Expr_Value_R (HB) < Expr_Value_R (T_LB));
6870 -- Fixed or discrete type case
6873 Null_Range := Expr_Value (HB) < Expr_Value (LB);
6875 (Expr_Value (LB) < Expr_Value (T_LB))
6877 (Expr_Value (LB) > Expr_Value (T_HB));
6880 (Expr_Value (HB) > Expr_Value (T_HB))
6882 (Expr_Value (HB) < Expr_Value (T_LB));
6885 if not Null_Range then
6886 if Out_Of_Range_L then
6887 if No (Warn_Node) then
6889 (Compile_Time_Constraint_Error
6890 (Low_Bound (Ck_Node),
6891 "static value out of range of}?", T_Typ));
6895 (Compile_Time_Constraint_Error
6897 "static range out of bounds of}?", T_Typ));
6901 if Out_Of_Range_H then
6902 if No (Warn_Node) then
6904 (Compile_Time_Constraint_Error
6905 (High_Bound (Ck_Node),
6906 "static value out of range of}?", T_Typ));
6910 (Compile_Time_Constraint_Error
6912 "static range out of bounds of}?", T_Typ));
6919 LB : Node_Id := Low_Bound (Ck_Node);
6920 HB : Node_Id := High_Bound (Ck_Node);
6923 -- If either bound is a discriminant and we are within the
6924 -- record declaration, it is a use of the discriminant in a
6925 -- constraint of a component, and nothing can be checked
6926 -- here. The check will be emitted within the init proc.
6927 -- Before then, the discriminal has no real meaning.
6928 -- Similarly, if the entity is a discriminal, there is no
6929 -- check to perform yet.
6931 -- The same holds within a discriminated synchronized type,
6932 -- where the discriminant may constrain a component or an
6935 if Nkind (LB) = N_Identifier
6936 and then Denotes_Discriminant (LB, True)
6938 if Current_Scope = Scope (Entity (LB))
6939 or else Is_Concurrent_Type (Current_Scope)
6940 or else Ekind (Entity (LB)) /= E_Discriminant
6945 New_Occurrence_Of (Discriminal (Entity (LB)), Loc);
6949 if Nkind (HB) = N_Identifier
6950 and then Denotes_Discriminant (HB, True)
6952 if Current_Scope = Scope (Entity (HB))
6953 or else Is_Concurrent_Type (Current_Scope)
6954 or else Ekind (Entity (HB)) /= E_Discriminant
6959 New_Occurrence_Of (Discriminal (Entity (HB)), Loc);
6963 Cond := Discrete_Range_Cond (Ck_Node, T_Typ);
6964 Set_Paren_Count (Cond, 1);
6970 Left_Opnd => Duplicate_Subexpr_No_Checks (HB),
6971 Right_Opnd => Duplicate_Subexpr_No_Checks (LB)),
6972 Right_Opnd => Cond);
6977 elsif Is_Scalar_Type (S_Typ) then
6979 -- This somewhat duplicates what Apply_Scalar_Range_Check does,
6980 -- except the above simply sets a flag in the node and lets
6981 -- gigi generate the check base on the Etype of the expression.
6982 -- Sometimes, however we want to do a dynamic check against an
6983 -- arbitrary target type, so we do that here.
6985 if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then
6986 Cond := Discrete_Expr_Cond (Ck_Node, T_Typ);
6988 -- For literals, we can tell if the constraint error will be
6989 -- raised at compile time, so we never need a dynamic check, but
6990 -- if the exception will be raised, then post the usual warning,
6991 -- and replace the literal with a raise constraint error
6992 -- expression. As usual, skip this for access types
6994 elsif Compile_Time_Known_Value (Ck_Node)
6995 and then not Do_Access
6998 LB : constant Node_Id := Type_Low_Bound (T_Typ);
6999 UB : constant Node_Id := Type_High_Bound (T_Typ);
7001 Out_Of_Range : Boolean;
7002 Static_Bounds : constant Boolean :=
7003 Compile_Time_Known_Value (LB)
7004 and Compile_Time_Known_Value (UB);
7007 -- Following range tests should use Sem_Eval routine ???
7009 if Static_Bounds then
7010 if Is_Floating_Point_Type (S_Typ) then
7012 (Expr_Value_R (Ck_Node) < Expr_Value_R (LB))
7014 (Expr_Value_R (Ck_Node) > Expr_Value_R (UB));
7016 -- Fixed or discrete type
7020 Expr_Value (Ck_Node) < Expr_Value (LB)
7022 Expr_Value (Ck_Node) > Expr_Value (UB);
7025 -- Bounds of the type are static and the literal is out of
7026 -- range so output a warning message.
7028 if Out_Of_Range then
7029 if No (Warn_Node) then
7031 (Compile_Time_Constraint_Error
7033 "static value out of range of}?", T_Typ));
7037 (Compile_Time_Constraint_Error
7039 "static value out of range of}?", T_Typ));
7044 Cond := Discrete_Expr_Cond (Ck_Node, T_Typ);
7048 -- Here for the case of a non-static expression, we need a runtime
7049 -- check unless the source type range is guaranteed to be in the
7050 -- range of the target type.
7053 if not In_Subrange_Of (S_Typ, T_Typ) then
7054 Cond := Discrete_Expr_Cond (Ck_Node, T_Typ);
7059 if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then
7060 if Is_Constrained (T_Typ) then
7062 Expr_Actual := Get_Referenced_Object (Ck_Node);
7063 Exptyp := Get_Actual_Subtype (Expr_Actual);
7065 if Is_Access_Type (Exptyp) then
7066 Exptyp := Designated_Type (Exptyp);
7069 -- String_Literal case. This needs to be handled specially be-
7070 -- cause no index types are available for string literals. The
7071 -- condition is simply:
7073 -- T_Typ'Length = string-literal-length
7075 if Nkind (Expr_Actual) = N_String_Literal then
7078 -- General array case. Here we have a usable actual subtype for
7079 -- the expression, and the condition is built from the two types
7081 -- T_Typ'First < Exptyp'First or else
7082 -- T_Typ'Last > Exptyp'Last or else
7083 -- T_Typ'First(1) < Exptyp'First(1) or else
7084 -- T_Typ'Last(1) > Exptyp'Last(1) or else
7087 elsif Is_Constrained (Exptyp) then
7089 Ndims : constant Nat := Number_Dimensions (T_Typ);
7095 L_Index := First_Index (T_Typ);
7096 R_Index := First_Index (Exptyp);
7098 for Indx in 1 .. Ndims loop
7099 if not (Nkind (L_Index) = N_Raise_Constraint_Error
7101 Nkind (R_Index) = N_Raise_Constraint_Error)
7103 -- Deal with compile time length check. Note that we
7104 -- skip this in the access case, because the access
7105 -- value may be null, so we cannot know statically.
7108 Subtypes_Statically_Match
7109 (Etype (L_Index), Etype (R_Index))
7111 -- If the target type is constrained then we
7112 -- have to check for exact equality of bounds
7113 -- (required for qualified expressions).
7115 if Is_Constrained (T_Typ) then
7118 Range_Equal_E_Cond (Exptyp, T_Typ, Indx));
7121 (Cond, Range_E_Cond (Exptyp, T_Typ, Indx));
7131 -- Handle cases where we do not get a usable actual subtype that
7132 -- is constrained. This happens for example in the function call
7133 -- and explicit dereference cases. In these cases, we have to get
7134 -- the length or range from the expression itself, making sure we
7135 -- do not evaluate it more than once.
7137 -- Here Ck_Node is the original expression, or more properly the
7138 -- result of applying Duplicate_Expr to the original tree,
7139 -- forcing the result to be a name.
7143 Ndims : constant Nat := Number_Dimensions (T_Typ);
7146 -- Build the condition for the explicit dereference case
7148 for Indx in 1 .. Ndims loop
7150 (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx));
7156 -- For a conversion to an unconstrained array type, generate an
7157 -- Action to check that the bounds of the source value are within
7158 -- the constraints imposed by the target type (RM 4.6(38)). No
7159 -- check is needed for a conversion to an access to unconstrained
7160 -- array type, as 4.6(24.15/2) requires the designated subtypes
7161 -- of the two access types to statically match.
7163 if Nkind (Parent (Ck_Node)) = N_Type_Conversion
7164 and then not Do_Access
7167 Opnd_Index : Node_Id;
7168 Targ_Index : Node_Id;
7169 Opnd_Range : Node_Id;
7172 Opnd_Index := First_Index (Get_Actual_Subtype (Ck_Node));
7173 Targ_Index := First_Index (T_Typ);
7174 while Present (Opnd_Index) loop
7176 -- If the index is a range, use its bounds. If it is an
7177 -- entity (as will be the case if it is a named subtype
7178 -- or an itype created for a slice) retrieve its range.
7180 if Is_Entity_Name (Opnd_Index)
7181 and then Is_Type (Entity (Opnd_Index))
7183 Opnd_Range := Scalar_Range (Entity (Opnd_Index));
7185 Opnd_Range := Opnd_Index;
7188 if Nkind (Opnd_Range) = N_Range then
7190 (Low_Bound (Opnd_Range), Etype (Targ_Index),
7191 Assume_Valid => True)
7194 (High_Bound (Opnd_Range), Etype (Targ_Index),
7195 Assume_Valid => True)
7199 -- If null range, no check needed
7202 Compile_Time_Known_Value (High_Bound (Opnd_Range))
7204 Compile_Time_Known_Value (Low_Bound (Opnd_Range))
7206 Expr_Value (High_Bound (Opnd_Range)) <
7207 Expr_Value (Low_Bound (Opnd_Range))
7211 elsif Is_Out_Of_Range
7212 (Low_Bound (Opnd_Range), Etype (Targ_Index),
7213 Assume_Valid => True)
7216 (High_Bound (Opnd_Range), Etype (Targ_Index),
7217 Assume_Valid => True)
7220 (Compile_Time_Constraint_Error
7221 (Wnode, "value out of range of}?", T_Typ));
7227 (Opnd_Range, Etype (Targ_Index)));
7231 Next_Index (Opnd_Index);
7232 Next_Index (Targ_Index);
7239 -- Construct the test and insert into the tree
7241 if Present (Cond) then
7243 Cond := Guard_Access (Cond, Loc, Ck_Node);
7247 (Make_Raise_Constraint_Error (Loc,
7249 Reason => CE_Range_Check_Failed));
7253 end Selected_Range_Checks;
7255 -------------------------------
7256 -- Storage_Checks_Suppressed --
7257 -------------------------------
7259 function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is
7261 if Present (E) and then Checks_May_Be_Suppressed (E) then
7262 return Is_Check_Suppressed (E, Storage_Check);
7264 return Scope_Suppress (Storage_Check);
7266 end Storage_Checks_Suppressed;
7268 ---------------------------
7269 -- Tag_Checks_Suppressed --
7270 ---------------------------
7272 function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is
7275 if Kill_Tag_Checks (E) then
7277 elsif Checks_May_Be_Suppressed (E) then
7278 return Is_Check_Suppressed (E, Tag_Check);
7282 return Scope_Suppress (Tag_Check);
7283 end Tag_Checks_Suppressed;
7285 --------------------------
7286 -- Validity_Check_Range --
7287 --------------------------
7289 procedure Validity_Check_Range (N : Node_Id) is
7291 if Validity_Checks_On and Validity_Check_Operands then
7292 if Nkind (N) = N_Range then
7293 Ensure_Valid (Low_Bound (N));
7294 Ensure_Valid (High_Bound (N));
7297 end Validity_Check_Range;
7299 --------------------------------
7300 -- Validity_Checks_Suppressed --
7301 --------------------------------
7303 function Validity_Checks_Suppressed (E : Entity_Id) return Boolean is
7305 if Present (E) and then Checks_May_Be_Suppressed (E) then
7306 return Is_Check_Suppressed (E, Validity_Check);
7308 return Scope_Suppress (Validity_Check);
7310 end Validity_Checks_Suppressed;