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 : Entity_Id := Param_Entity (N);
483 Param_Level : Node_Id;
484 Type_Level : Node_Id;
487 if Ada_Version >= Ada_2012
488 and then not Present (Param_Ent)
489 and then Is_Entity_Name (N)
490 and then Ekind_In (Entity (N), E_Constant, E_Variable)
491 and then Present (Effective_Extra_Accessibility (Entity (N)))
493 Param_Ent := Entity (N);
494 while Present (Renamed_Object (Param_Ent)) loop
496 -- Renamed_Object must return an Entity_Name here
497 -- because of preceding "Present (E_E_A (...))" test.
499 Param_Ent := Entity (Renamed_Object (Param_Ent));
503 if Inside_A_Generic then
506 -- Only apply the run-time check if the access parameter has an
507 -- associated extra access level parameter and when the level of the
508 -- type is less deep than the level of the access parameter, and
509 -- accessibility checks are not suppressed.
511 elsif Present (Param_Ent)
512 and then Present (Extra_Accessibility (Param_Ent))
513 and then UI_Gt (Object_Access_Level (N),
514 Deepest_Type_Access_Level (Typ))
515 and then not Accessibility_Checks_Suppressed (Param_Ent)
516 and then not Accessibility_Checks_Suppressed (Typ)
519 New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc);
522 Make_Integer_Literal (Loc, Deepest_Type_Access_Level (Typ));
524 -- Raise Program_Error if the accessibility level of the access
525 -- parameter is deeper than the level of the target access type.
527 Insert_Action (Insert_Node,
528 Make_Raise_Program_Error (Loc,
531 Left_Opnd => Param_Level,
532 Right_Opnd => Type_Level),
533 Reason => PE_Accessibility_Check_Failed));
535 Analyze_And_Resolve (N);
537 end Apply_Accessibility_Check;
539 --------------------------------
540 -- Apply_Address_Clause_Check --
541 --------------------------------
543 procedure Apply_Address_Clause_Check (E : Entity_Id; N : Node_Id) is
544 AC : constant Node_Id := Address_Clause (E);
545 Loc : constant Source_Ptr := Sloc (AC);
546 Typ : constant Entity_Id := Etype (E);
547 Aexp : constant Node_Id := Expression (AC);
550 -- Address expression (not necessarily the same as Aexp, for example
551 -- when Aexp is a reference to a constant, in which case Expr gets
552 -- reset to reference the value expression of the constant.
554 procedure Compile_Time_Bad_Alignment;
555 -- Post error warnings when alignment is known to be incompatible. Note
556 -- that we do not go as far as inserting a raise of Program_Error since
557 -- this is an erroneous case, and it may happen that we are lucky and an
558 -- underaligned address turns out to be OK after all.
560 --------------------------------
561 -- Compile_Time_Bad_Alignment --
562 --------------------------------
564 procedure Compile_Time_Bad_Alignment is
566 if Address_Clause_Overlay_Warnings then
568 ("?specified address for& may be inconsistent with alignment ",
571 ("\?program execution may be erroneous (RM 13.3(27))",
573 Set_Address_Warning_Posted (AC);
575 end Compile_Time_Bad_Alignment;
577 -- Start of processing for Apply_Address_Clause_Check
580 -- See if alignment check needed. Note that we never need a check if the
581 -- maximum alignment is one, since the check will always succeed.
583 -- Note: we do not check for checks suppressed here, since that check
584 -- was done in Sem_Ch13 when the address clause was processed. We are
585 -- only called if checks were not suppressed. The reason for this is
586 -- that we have to delay the call to Apply_Alignment_Check till freeze
587 -- time (so that all types etc are elaborated), but we have to check
588 -- the status of check suppressing at the point of the address clause.
591 or else not Check_Address_Alignment (AC)
592 or else Maximum_Alignment = 1
597 -- Obtain expression from address clause
599 Expr := Expression (AC);
601 -- The following loop digs for the real expression to use in the check
604 -- For constant, get constant expression
606 if Is_Entity_Name (Expr)
607 and then Ekind (Entity (Expr)) = E_Constant
609 Expr := Constant_Value (Entity (Expr));
611 -- For unchecked conversion, get result to convert
613 elsif Nkind (Expr) = N_Unchecked_Type_Conversion then
614 Expr := Expression (Expr);
616 -- For (common case) of To_Address call, get argument
618 elsif Nkind (Expr) = N_Function_Call
619 and then Is_Entity_Name (Name (Expr))
620 and then Is_RTE (Entity (Name (Expr)), RE_To_Address)
622 Expr := First (Parameter_Associations (Expr));
624 if Nkind (Expr) = N_Parameter_Association then
625 Expr := Explicit_Actual_Parameter (Expr);
628 -- We finally have the real expression
635 -- See if we know that Expr has a bad alignment at compile time
637 if Compile_Time_Known_Value (Expr)
638 and then (Known_Alignment (E) or else Known_Alignment (Typ))
641 AL : Uint := Alignment (Typ);
644 -- The object alignment might be more restrictive than the
647 if Known_Alignment (E) then
651 if Expr_Value (Expr) mod AL /= 0 then
652 Compile_Time_Bad_Alignment;
658 -- If the expression has the form X'Address, then we can find out if
659 -- the object X has an alignment that is compatible with the object E.
660 -- If it hasn't or we don't know, we defer issuing the warning until
661 -- the end of the compilation to take into account back end annotations.
663 elsif Nkind (Expr) = N_Attribute_Reference
664 and then Attribute_Name (Expr) = Name_Address
665 and then Has_Compatible_Alignment (E, Prefix (Expr)) = Known_Compatible
670 -- Here we do not know if the value is acceptable. Strictly we don't
671 -- have to do anything, since if the alignment is bad, we have an
672 -- erroneous program. However we are allowed to check for erroneous
673 -- conditions and we decide to do this by default if the check is not
676 -- However, don't do the check if elaboration code is unwanted
678 if Restriction_Active (No_Elaboration_Code) then
681 -- Generate a check to raise PE if alignment may be inappropriate
684 -- If the original expression is a non-static constant, use the
685 -- name of the constant itself rather than duplicating its
686 -- defining expression, which was extracted above.
688 -- Note: Expr is empty if the address-clause is applied to in-mode
689 -- actuals (allowed by 13.1(22)).
691 if not Present (Expr)
693 (Is_Entity_Name (Expression (AC))
694 and then Ekind (Entity (Expression (AC))) = E_Constant
695 and then Nkind (Parent (Entity (Expression (AC))))
696 = N_Object_Declaration)
698 Expr := New_Copy_Tree (Expression (AC));
700 Remove_Side_Effects (Expr);
703 Insert_After_And_Analyze (N,
704 Make_Raise_Program_Error (Loc,
711 (RTE (RE_Integer_Address), Expr),
713 Make_Attribute_Reference (Loc,
714 Prefix => New_Occurrence_Of (E, Loc),
715 Attribute_Name => Name_Alignment)),
716 Right_Opnd => Make_Integer_Literal (Loc, Uint_0)),
717 Reason => PE_Misaligned_Address_Value),
718 Suppress => All_Checks);
723 -- If we have some missing run time component in configurable run time
724 -- mode then just skip the check (it is not required in any case).
726 when RE_Not_Available =>
728 end Apply_Address_Clause_Check;
730 -------------------------------------
731 -- Apply_Arithmetic_Overflow_Check --
732 -------------------------------------
734 -- This routine is called only if the type is an integer type, and a
735 -- software arithmetic overflow check may be needed for op (add, subtract,
736 -- or multiply). This check is performed only if Software_Overflow_Checking
737 -- is enabled and Do_Overflow_Check is set. In this case we expand the
738 -- operation into a more complex sequence of tests that ensures that
739 -- overflow is properly caught.
741 procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is
742 Loc : constant Source_Ptr := Sloc (N);
743 Typ : constant Entity_Id := Etype (N);
744 Rtyp : constant Entity_Id := Root_Type (Typ);
747 -- An interesting special case. If the arithmetic operation appears as
748 -- the operand of a type conversion:
752 -- and all the following conditions apply:
754 -- arithmetic operation is for a signed integer type
755 -- target type type1 is a static integer subtype
756 -- range of x and y are both included in the range of type1
757 -- range of x op y is included in the range of type1
758 -- size of type1 is at least twice the result size of op
760 -- then we don't do an overflow check in any case, instead we transform
761 -- the operation so that we end up with:
763 -- type1 (type1 (x) op type1 (y))
765 -- This avoids intermediate overflow before the conversion. It is
766 -- explicitly permitted by RM 3.5.4(24):
768 -- For the execution of a predefined operation of a signed integer
769 -- type, the implementation need not raise Constraint_Error if the
770 -- result is outside the base range of the type, so long as the
771 -- correct result is produced.
773 -- It's hard to imagine that any programmer counts on the exception
774 -- being raised in this case, and in any case it's wrong coding to
775 -- have this expectation, given the RM permission. Furthermore, other
776 -- Ada compilers do allow such out of range results.
778 -- Note that we do this transformation even if overflow checking is
779 -- off, since this is precisely about giving the "right" result and
780 -- avoiding the need for an overflow check.
782 -- Note: this circuit is partially redundant with respect to the similar
783 -- processing in Exp_Ch4.Expand_N_Type_Conversion, but the latter deals
784 -- with cases that do not come through here. We still need the following
785 -- processing even with the Exp_Ch4 code in place, since we want to be
786 -- sure not to generate the arithmetic overflow check in these cases
787 -- (Exp_Ch4 would have a hard time removing them once generated).
789 if Is_Signed_Integer_Type (Typ)
790 and then Nkind (Parent (N)) = N_Type_Conversion
793 Target_Type : constant Entity_Id :=
794 Base_Type (Entity (Subtype_Mark (Parent (N))));
808 if Is_Integer_Type (Target_Type)
809 and then RM_Size (Root_Type (Target_Type)) >= 2 * RM_Size (Rtyp)
811 Tlo := Expr_Value (Type_Low_Bound (Target_Type));
812 Thi := Expr_Value (Type_High_Bound (Target_Type));
815 (Left_Opnd (N), LOK, Llo, Lhi, Assume_Valid => True);
817 (Right_Opnd (N), ROK, Rlo, Rhi, Assume_Valid => True);
820 and then Tlo <= Llo and then Lhi <= Thi
821 and then Tlo <= Rlo and then Rhi <= Thi
823 Determine_Range (N, VOK, Vlo, Vhi, Assume_Valid => True);
825 if VOK and then Tlo <= Vlo and then Vhi <= Thi then
826 Rewrite (Left_Opnd (N),
827 Make_Type_Conversion (Loc,
828 Subtype_Mark => New_Occurrence_Of (Target_Type, Loc),
829 Expression => Relocate_Node (Left_Opnd (N))));
831 Rewrite (Right_Opnd (N),
832 Make_Type_Conversion (Loc,
833 Subtype_Mark => New_Occurrence_Of (Target_Type, Loc),
834 Expression => Relocate_Node (Right_Opnd (N))));
836 -- Rewrite the conversion operand so that the original
837 -- node is retained, in order to avoid the warning for
838 -- redundant conversions in Resolve_Type_Conversion.
840 Rewrite (N, Relocate_Node (N));
842 Set_Etype (N, Target_Type);
844 Analyze_And_Resolve (Left_Opnd (N), Target_Type);
845 Analyze_And_Resolve (Right_Opnd (N), Target_Type);
847 -- Given that the target type is twice the size of the
848 -- source type, overflow is now impossible, so we can
849 -- safely kill the overflow check and return.
851 Set_Do_Overflow_Check (N, False);
859 -- Now see if an overflow check is required
862 Siz : constant Int := UI_To_Int (Esize (Rtyp));
863 Dsiz : constant Int := Siz * 2;
870 -- Skip check if back end does overflow checks, or the overflow flag
871 -- is not set anyway, or we are not doing code expansion, or the
872 -- parent node is a type conversion whose operand is an arithmetic
873 -- operation on signed integers on which the expander can promote
874 -- later the operands to type Integer (see Expand_N_Type_Conversion).
876 -- Special case CLI target, where arithmetic overflow checks can be
877 -- performed for integer and long_integer
879 if Backend_Overflow_Checks_On_Target
880 or else not Do_Overflow_Check (N)
881 or else not Expander_Active
882 or else (Present (Parent (N))
883 and then Nkind (Parent (N)) = N_Type_Conversion
884 and then Integer_Promotion_Possible (Parent (N)))
886 (VM_Target = CLI_Target and then Siz >= Standard_Integer_Size)
891 -- Otherwise, generate the full general code for front end overflow
892 -- detection, which works by doing arithmetic in a larger type:
898 -- Typ (Checktyp (x) op Checktyp (y));
900 -- where Typ is the type of the original expression, and Checktyp is
901 -- an integer type of sufficient length to hold the largest possible
904 -- If the size of check type exceeds the size of Long_Long_Integer,
905 -- we use a different approach, expanding to:
907 -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y)))
909 -- where xxx is Add, Multiply or Subtract as appropriate
911 -- Find check type if one exists
913 if Dsiz <= Standard_Integer_Size then
914 Ctyp := Standard_Integer;
916 elsif Dsiz <= Standard_Long_Long_Integer_Size then
917 Ctyp := Standard_Long_Long_Integer;
919 -- No check type exists, use runtime call
922 if Nkind (N) = N_Op_Add then
923 Cent := RE_Add_With_Ovflo_Check;
925 elsif Nkind (N) = N_Op_Multiply then
926 Cent := RE_Multiply_With_Ovflo_Check;
929 pragma Assert (Nkind (N) = N_Op_Subtract);
930 Cent := RE_Subtract_With_Ovflo_Check;
935 Make_Function_Call (Loc,
936 Name => New_Reference_To (RTE (Cent), Loc),
937 Parameter_Associations => New_List (
938 OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)),
939 OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N))))));
941 Analyze_And_Resolve (N, Typ);
945 -- If we fall through, we have the case where we do the arithmetic
946 -- in the next higher type and get the check by conversion. In these
947 -- cases Ctyp is set to the type to be used as the check type.
949 Opnod := Relocate_Node (N);
951 Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod));
954 Set_Etype (Opnd, Ctyp);
955 Set_Analyzed (Opnd, True);
956 Set_Left_Opnd (Opnod, Opnd);
958 Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod));
961 Set_Etype (Opnd, Ctyp);
962 Set_Analyzed (Opnd, True);
963 Set_Right_Opnd (Opnod, Opnd);
965 -- The type of the operation changes to the base type of the check
966 -- type, and we reset the overflow check indication, since clearly no
967 -- overflow is possible now that we are using a double length type.
968 -- We also set the Analyzed flag to avoid a recursive attempt to
971 Set_Etype (Opnod, Base_Type (Ctyp));
972 Set_Do_Overflow_Check (Opnod, False);
973 Set_Analyzed (Opnod, True);
975 -- Now build the outer conversion
977 Opnd := OK_Convert_To (Typ, Opnod);
979 Set_Etype (Opnd, Typ);
981 -- In the discrete type case, we directly generate the range check
982 -- for the outer operand. This range check will implement the
983 -- required overflow check.
985 if Is_Discrete_Type (Typ) then
988 (Expression (N), Typ, CE_Overflow_Check_Failed);
990 -- For other types, we enable overflow checking on the conversion,
991 -- after setting the node as analyzed to prevent recursive attempts
992 -- to expand the conversion node.
995 Set_Analyzed (Opnd, True);
996 Enable_Overflow_Check (Opnd);
1001 when RE_Not_Available =>
1004 end Apply_Arithmetic_Overflow_Check;
1006 ----------------------------
1007 -- Apply_Constraint_Check --
1008 ----------------------------
1010 procedure Apply_Constraint_Check
1013 No_Sliding : Boolean := False)
1015 Desig_Typ : Entity_Id;
1018 -- No checks inside a generic (check the instantiations)
1020 if Inside_A_Generic then
1024 -- Apply required constraint checks
1026 if Is_Scalar_Type (Typ) then
1027 Apply_Scalar_Range_Check (N, Typ);
1029 elsif Is_Array_Type (Typ) then
1031 -- A useful optimization: an aggregate with only an others clause
1032 -- always has the right bounds.
1034 if Nkind (N) = N_Aggregate
1035 and then No (Expressions (N))
1037 (First (Choices (First (Component_Associations (N)))))
1043 if Is_Constrained (Typ) then
1044 Apply_Length_Check (N, Typ);
1047 Apply_Range_Check (N, Typ);
1050 Apply_Range_Check (N, Typ);
1053 elsif (Is_Record_Type (Typ)
1054 or else Is_Private_Type (Typ))
1055 and then Has_Discriminants (Base_Type (Typ))
1056 and then Is_Constrained (Typ)
1058 Apply_Discriminant_Check (N, Typ);
1060 elsif Is_Access_Type (Typ) then
1062 Desig_Typ := Designated_Type (Typ);
1064 -- No checks necessary if expression statically null
1066 if Known_Null (N) then
1067 if Can_Never_Be_Null (Typ) then
1068 Install_Null_Excluding_Check (N);
1071 -- No sliding possible on access to arrays
1073 elsif Is_Array_Type (Desig_Typ) then
1074 if Is_Constrained (Desig_Typ) then
1075 Apply_Length_Check (N, Typ);
1078 Apply_Range_Check (N, Typ);
1080 elsif Has_Discriminants (Base_Type (Desig_Typ))
1081 and then Is_Constrained (Desig_Typ)
1083 Apply_Discriminant_Check (N, Typ);
1086 -- Apply the 2005 Null_Excluding check. Note that we do not apply
1087 -- this check if the constraint node is illegal, as shown by having
1088 -- an error posted. This additional guard prevents cascaded errors
1089 -- and compiler aborts on illegal programs involving Ada 2005 checks.
1091 if Can_Never_Be_Null (Typ)
1092 and then not Can_Never_Be_Null (Etype (N))
1093 and then not Error_Posted (N)
1095 Install_Null_Excluding_Check (N);
1098 end Apply_Constraint_Check;
1100 ------------------------------
1101 -- Apply_Discriminant_Check --
1102 ------------------------------
1104 procedure Apply_Discriminant_Check
1107 Lhs : Node_Id := Empty)
1109 Loc : constant Source_Ptr := Sloc (N);
1110 Do_Access : constant Boolean := Is_Access_Type (Typ);
1111 S_Typ : Entity_Id := Etype (N);
1115 function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean;
1116 -- A heap object with an indefinite subtype is constrained by its
1117 -- initial value, and assigning to it requires a constraint_check.
1118 -- The target may be an explicit dereference, or a renaming of one.
1120 function Is_Aliased_Unconstrained_Component return Boolean;
1121 -- It is possible for an aliased component to have a nominal
1122 -- unconstrained subtype (through instantiation). If this is a
1123 -- discriminated component assigned in the expansion of an aggregate
1124 -- in an initialization, the check must be suppressed. This unusual
1125 -- situation requires a predicate of its own.
1127 ----------------------------------
1128 -- Denotes_Explicit_Dereference --
1129 ----------------------------------
1131 function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean is
1134 Nkind (Obj) = N_Explicit_Dereference
1136 (Is_Entity_Name (Obj)
1137 and then Present (Renamed_Object (Entity (Obj)))
1138 and then Nkind (Renamed_Object (Entity (Obj))) =
1139 N_Explicit_Dereference);
1140 end Denotes_Explicit_Dereference;
1142 ----------------------------------------
1143 -- Is_Aliased_Unconstrained_Component --
1144 ----------------------------------------
1146 function Is_Aliased_Unconstrained_Component return Boolean is
1151 if Nkind (Lhs) /= N_Selected_Component then
1154 Comp := Entity (Selector_Name (Lhs));
1155 Pref := Prefix (Lhs);
1158 if Ekind (Comp) /= E_Component
1159 or else not Is_Aliased (Comp)
1164 return not Comes_From_Source (Pref)
1165 and then In_Instance
1166 and then not Is_Constrained (Etype (Comp));
1167 end Is_Aliased_Unconstrained_Component;
1169 -- Start of processing for Apply_Discriminant_Check
1173 T_Typ := Designated_Type (Typ);
1178 -- Nothing to do if discriminant checks are suppressed or else no code
1179 -- is to be generated
1181 if not Expander_Active
1182 or else Discriminant_Checks_Suppressed (T_Typ)
1187 -- No discriminant checks necessary for an access when expression is
1188 -- statically Null. This is not only an optimization, it is fundamental
1189 -- because otherwise discriminant checks may be generated in init procs
1190 -- for types containing an access to a not-yet-frozen record, causing a
1191 -- deadly forward reference.
1193 -- Also, if the expression is of an access type whose designated type is
1194 -- incomplete, then the access value must be null and we suppress the
1197 if Known_Null (N) then
1200 elsif Is_Access_Type (S_Typ) then
1201 S_Typ := Designated_Type (S_Typ);
1203 if Ekind (S_Typ) = E_Incomplete_Type then
1208 -- If an assignment target is present, then we need to generate the
1209 -- actual subtype if the target is a parameter or aliased object with
1210 -- an unconstrained nominal subtype.
1212 -- Ada 2005 (AI-363): For Ada 2005, we limit the building of the actual
1213 -- subtype to the parameter and dereference cases, since other aliased
1214 -- objects are unconstrained (unless the nominal subtype is explicitly
1218 and then (Present (Param_Entity (Lhs))
1219 or else (Ada_Version < Ada_2005
1220 and then not Is_Constrained (T_Typ)
1221 and then Is_Aliased_View (Lhs)
1222 and then not Is_Aliased_Unconstrained_Component)
1223 or else (Ada_Version >= Ada_2005
1224 and then not Is_Constrained (T_Typ)
1225 and then Denotes_Explicit_Dereference (Lhs)
1226 and then Nkind (Original_Node (Lhs)) /=
1229 T_Typ := Get_Actual_Subtype (Lhs);
1232 -- Nothing to do if the type is unconstrained (this is the case where
1233 -- the actual subtype in the RM sense of N is unconstrained and no check
1236 if not Is_Constrained (T_Typ) then
1239 -- Ada 2005: nothing to do if the type is one for which there is a
1240 -- partial view that is constrained.
1242 elsif Ada_Version >= Ada_2005
1243 and then Has_Constrained_Partial_View (Base_Type (T_Typ))
1248 -- Nothing to do if the type is an Unchecked_Union
1250 if Is_Unchecked_Union (Base_Type (T_Typ)) then
1254 -- Suppress checks if the subtypes are the same. the check must be
1255 -- preserved in an assignment to a formal, because the constraint is
1256 -- given by the actual.
1258 if Nkind (Original_Node (N)) /= N_Allocator
1260 or else not Is_Entity_Name (Lhs)
1261 or else No (Param_Entity (Lhs)))
1264 or else (Do_Access and then Designated_Type (Typ) = S_Typ))
1265 and then not Is_Aliased_View (Lhs)
1270 -- We can also eliminate checks on allocators with a subtype mark that
1271 -- coincides with the context type. The context type may be a subtype
1272 -- without a constraint (common case, a generic actual).
1274 elsif Nkind (Original_Node (N)) = N_Allocator
1275 and then Is_Entity_Name (Expression (Original_Node (N)))
1278 Alloc_Typ : constant Entity_Id :=
1279 Entity (Expression (Original_Node (N)));
1282 if Alloc_Typ = T_Typ
1283 or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration
1284 and then Is_Entity_Name (
1285 Subtype_Indication (Parent (T_Typ)))
1286 and then Alloc_Typ = Base_Type (T_Typ))
1294 -- See if we have a case where the types are both constrained, and all
1295 -- the constraints are constants. In this case, we can do the check
1296 -- successfully at compile time.
1298 -- We skip this check for the case where the node is a rewritten`
1299 -- allocator, because it already carries the context subtype, and
1300 -- extracting the discriminants from the aggregate is messy.
1302 if Is_Constrained (S_Typ)
1303 and then Nkind (Original_Node (N)) /= N_Allocator
1313 -- S_Typ may not have discriminants in the case where it is a
1314 -- private type completed by a default discriminated type. In that
1315 -- case, we need to get the constraints from the underlying_type.
1316 -- If the underlying type is unconstrained (i.e. has no default
1317 -- discriminants) no check is needed.
1319 if Has_Discriminants (S_Typ) then
1320 Discr := First_Discriminant (S_Typ);
1321 DconS := First_Elmt (Discriminant_Constraint (S_Typ));
1324 Discr := First_Discriminant (Underlying_Type (S_Typ));
1327 (Discriminant_Constraint (Underlying_Type (S_Typ)));
1333 -- A further optimization: if T_Typ is derived from S_Typ
1334 -- without imposing a constraint, no check is needed.
1336 if Nkind (Original_Node (Parent (T_Typ))) =
1337 N_Full_Type_Declaration
1340 Type_Def : constant Node_Id :=
1342 (Original_Node (Parent (T_Typ)));
1344 if Nkind (Type_Def) = N_Derived_Type_Definition
1345 and then Is_Entity_Name (Subtype_Indication (Type_Def))
1346 and then Entity (Subtype_Indication (Type_Def)) = S_Typ
1354 DconT := First_Elmt (Discriminant_Constraint (T_Typ));
1356 while Present (Discr) loop
1357 ItemS := Node (DconS);
1358 ItemT := Node (DconT);
1360 -- For a discriminated component type constrained by the
1361 -- current instance of an enclosing type, there is no
1362 -- applicable discriminant check.
1364 if Nkind (ItemT) = N_Attribute_Reference
1365 and then Is_Access_Type (Etype (ItemT))
1366 and then Is_Entity_Name (Prefix (ItemT))
1367 and then Is_Type (Entity (Prefix (ItemT)))
1372 -- If the expressions for the discriminants are identical
1373 -- and it is side-effect free (for now just an entity),
1374 -- this may be a shared constraint, e.g. from a subtype
1375 -- without a constraint introduced as a generic actual.
1376 -- Examine other discriminants if any.
1379 and then Is_Entity_Name (ItemS)
1383 elsif not Is_OK_Static_Expression (ItemS)
1384 or else not Is_OK_Static_Expression (ItemT)
1388 elsif Expr_Value (ItemS) /= Expr_Value (ItemT) then
1389 if Do_Access then -- needs run-time check.
1392 Apply_Compile_Time_Constraint_Error
1393 (N, "incorrect value for discriminant&?",
1394 CE_Discriminant_Check_Failed, Ent => Discr);
1401 Next_Discriminant (Discr);
1410 -- Here we need a discriminant check. First build the expression
1411 -- for the comparisons of the discriminants:
1413 -- (n.disc1 /= typ.disc1) or else
1414 -- (n.disc2 /= typ.disc2) or else
1416 -- (n.discn /= typ.discn)
1418 Cond := Build_Discriminant_Checks (N, T_Typ);
1420 -- If Lhs is set and is a parameter, then the condition is
1421 -- guarded by: lhs'constrained and then (condition built above)
1423 if Present (Param_Entity (Lhs)) then
1427 Make_Attribute_Reference (Loc,
1428 Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc),
1429 Attribute_Name => Name_Constrained),
1430 Right_Opnd => Cond);
1434 Cond := Guard_Access (Cond, Loc, N);
1438 Make_Raise_Constraint_Error (Loc,
1440 Reason => CE_Discriminant_Check_Failed));
1441 end Apply_Discriminant_Check;
1443 ------------------------
1444 -- Apply_Divide_Check --
1445 ------------------------
1447 procedure Apply_Divide_Check (N : Node_Id) is
1448 Loc : constant Source_Ptr := Sloc (N);
1449 Typ : constant Entity_Id := Etype (N);
1450 Left : constant Node_Id := Left_Opnd (N);
1451 Right : constant Node_Id := Right_Opnd (N);
1461 pragma Warnings (Off, Lhi);
1462 -- Don't actually use this value
1466 and then not Backend_Divide_Checks_On_Target
1467 and then Check_Needed (Right, Division_Check)
1469 Determine_Range (Right, ROK, Rlo, Rhi, Assume_Valid => True);
1471 -- See if division by zero possible, and if so generate test. This
1472 -- part of the test is not controlled by the -gnato switch.
1474 if Do_Division_Check (N) then
1475 if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then
1477 Make_Raise_Constraint_Error (Loc,
1480 Left_Opnd => Duplicate_Subexpr_Move_Checks (Right),
1481 Right_Opnd => Make_Integer_Literal (Loc, 0)),
1482 Reason => CE_Divide_By_Zero));
1486 -- Test for extremely annoying case of xxx'First divided by -1
1488 if Do_Overflow_Check (N) then
1489 if Nkind (N) = N_Op_Divide
1490 and then Is_Signed_Integer_Type (Typ)
1492 Determine_Range (Left, LOK, Llo, Lhi, Assume_Valid => True);
1493 LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ)));
1495 if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi))
1497 ((not LOK) or else (Llo = LLB))
1500 Make_Raise_Constraint_Error (Loc,
1506 Duplicate_Subexpr_Move_Checks (Left),
1507 Right_Opnd => Make_Integer_Literal (Loc, LLB)),
1511 Duplicate_Subexpr (Right),
1513 Make_Integer_Literal (Loc, -1))),
1514 Reason => CE_Overflow_Check_Failed));
1519 end Apply_Divide_Check;
1521 ----------------------------------
1522 -- Apply_Float_Conversion_Check --
1523 ----------------------------------
1525 -- Let F and I be the source and target types of the conversion. The RM
1526 -- specifies that a floating-point value X is rounded to the nearest
1527 -- integer, with halfway cases being rounded away from zero. The rounded
1528 -- value of X is checked against I'Range.
1530 -- The catch in the above paragraph is that there is no good way to know
1531 -- whether the round-to-integer operation resulted in overflow. A remedy is
1532 -- to perform a range check in the floating-point domain instead, however:
1534 -- (1) The bounds may not be known at compile time
1535 -- (2) The check must take into account rounding or truncation.
1536 -- (3) The range of type I may not be exactly representable in F.
1537 -- (4) For the rounding case, The end-points I'First - 0.5 and
1538 -- I'Last + 0.5 may or may not be in range, depending on the
1539 -- sign of I'First and I'Last.
1540 -- (5) X may be a NaN, which will fail any comparison
1542 -- The following steps correctly convert X with rounding:
1544 -- (1) If either I'First or I'Last is not known at compile time, use
1545 -- I'Base instead of I in the next three steps and perform a
1546 -- regular range check against I'Range after conversion.
1547 -- (2) If I'First - 0.5 is representable in F then let Lo be that
1548 -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be
1549 -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First).
1550 -- In other words, take one of the closest floating-point numbers
1551 -- (which is an integer value) to I'First, and see if it is in
1553 -- (3) If I'Last + 0.5 is representable in F then let Hi be that value
1554 -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be
1555 -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last).
1556 -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo)
1557 -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi)
1559 -- For the truncating case, replace steps (2) and (3) as follows:
1560 -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK
1561 -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let
1563 -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK
1564 -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let
1567 procedure Apply_Float_Conversion_Check
1569 Target_Typ : Entity_Id)
1571 LB : constant Node_Id := Type_Low_Bound (Target_Typ);
1572 HB : constant Node_Id := Type_High_Bound (Target_Typ);
1573 Loc : constant Source_Ptr := Sloc (Ck_Node);
1574 Expr_Type : constant Entity_Id := Base_Type (Etype (Ck_Node));
1575 Target_Base : constant Entity_Id :=
1576 Implementation_Base_Type (Target_Typ);
1578 Par : constant Node_Id := Parent (Ck_Node);
1579 pragma Assert (Nkind (Par) = N_Type_Conversion);
1580 -- Parent of check node, must be a type conversion
1582 Truncate : constant Boolean := Float_Truncate (Par);
1583 Max_Bound : constant Uint :=
1585 (Machine_Radix_Value (Expr_Type),
1586 Machine_Mantissa_Value (Expr_Type) - 1) - 1;
1588 -- Largest bound, so bound plus or minus half is a machine number of F
1590 Ifirst, Ilast : Uint;
1591 -- Bounds of integer type
1594 -- Bounds to check in floating-point domain
1596 Lo_OK, Hi_OK : Boolean;
1597 -- True iff Lo resp. Hi belongs to I'Range
1599 Lo_Chk, Hi_Chk : Node_Id;
1600 -- Expressions that are False iff check fails
1602 Reason : RT_Exception_Code;
1605 if not Compile_Time_Known_Value (LB)
1606 or not Compile_Time_Known_Value (HB)
1609 -- First check that the value falls in the range of the base type,
1610 -- to prevent overflow during conversion and then perform a
1611 -- regular range check against the (dynamic) bounds.
1613 pragma Assert (Target_Base /= Target_Typ);
1615 Temp : constant Entity_Id := Make_Temporary (Loc, 'T', Par);
1618 Apply_Float_Conversion_Check (Ck_Node, Target_Base);
1619 Set_Etype (Temp, Target_Base);
1621 Insert_Action (Parent (Par),
1622 Make_Object_Declaration (Loc,
1623 Defining_Identifier => Temp,
1624 Object_Definition => New_Occurrence_Of (Target_Typ, Loc),
1625 Expression => New_Copy_Tree (Par)),
1626 Suppress => All_Checks);
1629 Make_Raise_Constraint_Error (Loc,
1632 Left_Opnd => New_Occurrence_Of (Temp, Loc),
1633 Right_Opnd => New_Occurrence_Of (Target_Typ, Loc)),
1634 Reason => CE_Range_Check_Failed));
1635 Rewrite (Par, New_Occurrence_Of (Temp, Loc));
1641 -- Get the (static) bounds of the target type
1643 Ifirst := Expr_Value (LB);
1644 Ilast := Expr_Value (HB);
1646 -- A simple optimization: if the expression is a universal literal,
1647 -- we can do the comparison with the bounds and the conversion to
1648 -- an integer type statically. The range checks are unchanged.
1650 if Nkind (Ck_Node) = N_Real_Literal
1651 and then Etype (Ck_Node) = Universal_Real
1652 and then Is_Integer_Type (Target_Typ)
1653 and then Nkind (Parent (Ck_Node)) = N_Type_Conversion
1656 Int_Val : constant Uint := UR_To_Uint (Realval (Ck_Node));
1659 if Int_Val <= Ilast and then Int_Val >= Ifirst then
1661 -- Conversion is safe
1663 Rewrite (Parent (Ck_Node),
1664 Make_Integer_Literal (Loc, UI_To_Int (Int_Val)));
1665 Analyze_And_Resolve (Parent (Ck_Node), Target_Typ);
1671 -- Check against lower bound
1673 if Truncate and then Ifirst > 0 then
1674 Lo := Pred (Expr_Type, UR_From_Uint (Ifirst));
1678 Lo := Succ (Expr_Type, UR_From_Uint (Ifirst - 1));
1681 elsif abs (Ifirst) < Max_Bound then
1682 Lo := UR_From_Uint (Ifirst) - Ureal_Half;
1683 Lo_OK := (Ifirst > 0);
1686 Lo := Machine (Expr_Type, UR_From_Uint (Ifirst), Round_Even, Ck_Node);
1687 Lo_OK := (Lo >= UR_From_Uint (Ifirst));
1692 -- Lo_Chk := (X >= Lo)
1694 Lo_Chk := Make_Op_Ge (Loc,
1695 Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
1696 Right_Opnd => Make_Real_Literal (Loc, Lo));
1699 -- Lo_Chk := (X > Lo)
1701 Lo_Chk := Make_Op_Gt (Loc,
1702 Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
1703 Right_Opnd => Make_Real_Literal (Loc, Lo));
1706 -- Check against higher bound
1708 if Truncate and then Ilast < 0 then
1709 Hi := Succ (Expr_Type, UR_From_Uint (Ilast));
1713 Hi := Pred (Expr_Type, UR_From_Uint (Ilast + 1));
1716 elsif abs (Ilast) < Max_Bound then
1717 Hi := UR_From_Uint (Ilast) + Ureal_Half;
1718 Hi_OK := (Ilast < 0);
1720 Hi := Machine (Expr_Type, UR_From_Uint (Ilast), Round_Even, Ck_Node);
1721 Hi_OK := (Hi <= UR_From_Uint (Ilast));
1726 -- Hi_Chk := (X <= Hi)
1728 Hi_Chk := Make_Op_Le (Loc,
1729 Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
1730 Right_Opnd => Make_Real_Literal (Loc, Hi));
1733 -- Hi_Chk := (X < Hi)
1735 Hi_Chk := Make_Op_Lt (Loc,
1736 Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
1737 Right_Opnd => Make_Real_Literal (Loc, Hi));
1740 -- If the bounds of the target type are the same as those of the base
1741 -- type, the check is an overflow check as a range check is not
1742 -- performed in these cases.
1744 if Expr_Value (Type_Low_Bound (Target_Base)) = Ifirst
1745 and then Expr_Value (Type_High_Bound (Target_Base)) = Ilast
1747 Reason := CE_Overflow_Check_Failed;
1749 Reason := CE_Range_Check_Failed;
1752 -- Raise CE if either conditions does not hold
1754 Insert_Action (Ck_Node,
1755 Make_Raise_Constraint_Error (Loc,
1756 Condition => Make_Op_Not (Loc, Make_And_Then (Loc, Lo_Chk, Hi_Chk)),
1758 end Apply_Float_Conversion_Check;
1760 ------------------------
1761 -- Apply_Length_Check --
1762 ------------------------
1764 procedure Apply_Length_Check
1766 Target_Typ : Entity_Id;
1767 Source_Typ : Entity_Id := Empty)
1770 Apply_Selected_Length_Checks
1771 (Ck_Node, Target_Typ, Source_Typ, Do_Static => False);
1772 end Apply_Length_Check;
1774 ---------------------------
1775 -- Apply_Predicate_Check --
1776 ---------------------------
1778 procedure Apply_Predicate_Check (N : Node_Id; Typ : Entity_Id) is
1780 if Present (Predicate_Function (Typ)) then
1782 Make_Predicate_Check (Typ, Duplicate_Subexpr (N)));
1784 end Apply_Predicate_Check;
1786 -----------------------
1787 -- Apply_Range_Check --
1788 -----------------------
1790 procedure Apply_Range_Check
1792 Target_Typ : Entity_Id;
1793 Source_Typ : Entity_Id := Empty)
1796 Apply_Selected_Range_Checks
1797 (Ck_Node, Target_Typ, Source_Typ, Do_Static => False);
1798 end Apply_Range_Check;
1800 ------------------------------
1801 -- Apply_Scalar_Range_Check --
1802 ------------------------------
1804 -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag
1805 -- off if it is already set on.
1807 procedure Apply_Scalar_Range_Check
1809 Target_Typ : Entity_Id;
1810 Source_Typ : Entity_Id := Empty;
1811 Fixed_Int : Boolean := False)
1813 Parnt : constant Node_Id := Parent (Expr);
1815 Arr : Node_Id := Empty; -- initialize to prevent warning
1816 Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning
1819 Is_Subscr_Ref : Boolean;
1820 -- Set true if Expr is a subscript
1822 Is_Unconstrained_Subscr_Ref : Boolean;
1823 -- Set true if Expr is a subscript of an unconstrained array. In this
1824 -- case we do not attempt to do an analysis of the value against the
1825 -- range of the subscript, since we don't know the actual subtype.
1828 -- Set to True if Expr should be regarded as a real value even though
1829 -- the type of Expr might be discrete.
1831 procedure Bad_Value;
1832 -- Procedure called if value is determined to be out of range
1838 procedure Bad_Value is
1840 Apply_Compile_Time_Constraint_Error
1841 (Expr, "value not in range of}?", CE_Range_Check_Failed,
1846 -- Start of processing for Apply_Scalar_Range_Check
1849 -- Return if check obviously not needed
1852 -- Not needed inside generic
1856 -- Not needed if previous error
1858 or else Target_Typ = Any_Type
1859 or else Nkind (Expr) = N_Error
1861 -- Not needed for non-scalar type
1863 or else not Is_Scalar_Type (Target_Typ)
1865 -- Not needed if we know node raises CE already
1867 or else Raises_Constraint_Error (Expr)
1872 -- Now, see if checks are suppressed
1875 Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component;
1877 if Is_Subscr_Ref then
1878 Arr := Prefix (Parnt);
1879 Arr_Typ := Get_Actual_Subtype_If_Available (Arr);
1882 if not Do_Range_Check (Expr) then
1884 -- Subscript reference. Check for Index_Checks suppressed
1886 if Is_Subscr_Ref then
1888 -- Check array type and its base type
1890 if Index_Checks_Suppressed (Arr_Typ)
1891 or else Index_Checks_Suppressed (Base_Type (Arr_Typ))
1895 -- Check array itself if it is an entity name
1897 elsif Is_Entity_Name (Arr)
1898 and then Index_Checks_Suppressed (Entity (Arr))
1902 -- Check expression itself if it is an entity name
1904 elsif Is_Entity_Name (Expr)
1905 and then Index_Checks_Suppressed (Entity (Expr))
1910 -- All other cases, check for Range_Checks suppressed
1913 -- Check target type and its base type
1915 if Range_Checks_Suppressed (Target_Typ)
1916 or else Range_Checks_Suppressed (Base_Type (Target_Typ))
1920 -- Check expression itself if it is an entity name
1922 elsif Is_Entity_Name (Expr)
1923 and then Range_Checks_Suppressed (Entity (Expr))
1927 -- If Expr is part of an assignment statement, then check left
1928 -- side of assignment if it is an entity name.
1930 elsif Nkind (Parnt) = N_Assignment_Statement
1931 and then Is_Entity_Name (Name (Parnt))
1932 and then Range_Checks_Suppressed (Entity (Name (Parnt)))
1939 -- Do not set range checks if they are killed
1941 if Nkind (Expr) = N_Unchecked_Type_Conversion
1942 and then Kill_Range_Check (Expr)
1947 -- Do not set range checks for any values from System.Scalar_Values
1948 -- since the whole idea of such values is to avoid checking them!
1950 if Is_Entity_Name (Expr)
1951 and then Is_RTU (Scope (Entity (Expr)), System_Scalar_Values)
1956 -- Now see if we need a check
1958 if No (Source_Typ) then
1959 S_Typ := Etype (Expr);
1961 S_Typ := Source_Typ;
1964 if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then
1968 Is_Unconstrained_Subscr_Ref :=
1969 Is_Subscr_Ref and then not Is_Constrained (Arr_Typ);
1971 -- Always do a range check if the source type includes infinities and
1972 -- the target type does not include infinities. We do not do this if
1973 -- range checks are killed.
1975 if Is_Floating_Point_Type (S_Typ)
1976 and then Has_Infinities (S_Typ)
1977 and then not Has_Infinities (Target_Typ)
1979 Enable_Range_Check (Expr);
1982 -- Return if we know expression is definitely in the range of the target
1983 -- type as determined by Determine_Range. Right now we only do this for
1984 -- discrete types, and not fixed-point or floating-point types.
1986 -- The additional less-precise tests below catch these cases
1988 -- Note: skip this if we are given a source_typ, since the point of
1989 -- supplying a Source_Typ is to stop us looking at the expression.
1990 -- We could sharpen this test to be out parameters only ???
1992 if Is_Discrete_Type (Target_Typ)
1993 and then Is_Discrete_Type (Etype (Expr))
1994 and then not Is_Unconstrained_Subscr_Ref
1995 and then No (Source_Typ)
1998 Tlo : constant Node_Id := Type_Low_Bound (Target_Typ);
1999 Thi : constant Node_Id := Type_High_Bound (Target_Typ);
2004 if Compile_Time_Known_Value (Tlo)
2005 and then Compile_Time_Known_Value (Thi)
2008 Lov : constant Uint := Expr_Value (Tlo);
2009 Hiv : constant Uint := Expr_Value (Thi);
2012 -- If range is null, we for sure have a constraint error
2013 -- (we don't even need to look at the value involved,
2014 -- since all possible values will raise CE).
2021 -- Otherwise determine range of value
2023 Determine_Range (Expr, OK, Lo, Hi, Assume_Valid => True);
2027 -- If definitely in range, all OK
2029 if Lo >= Lov and then Hi <= Hiv then
2032 -- If definitely not in range, warn
2034 elsif Lov > Hi or else Hiv < Lo then
2038 -- Otherwise we don't know
2050 Is_Floating_Point_Type (S_Typ)
2051 or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int);
2053 -- Check if we can determine at compile time whether Expr is in the
2054 -- range of the target type. Note that if S_Typ is within the bounds
2055 -- of Target_Typ then this must be the case. This check is meaningful
2056 -- only if this is not a conversion between integer and real types.
2058 if not Is_Unconstrained_Subscr_Ref
2060 Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ)
2062 (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int)
2064 Is_In_Range (Expr, Target_Typ,
2065 Assume_Valid => True,
2066 Fixed_Int => Fixed_Int,
2067 Int_Real => Int_Real))
2071 elsif Is_Out_Of_Range (Expr, Target_Typ,
2072 Assume_Valid => True,
2073 Fixed_Int => Fixed_Int,
2074 Int_Real => Int_Real)
2079 -- In the floating-point case, we only do range checks if the type is
2080 -- constrained. We definitely do NOT want range checks for unconstrained
2081 -- types, since we want to have infinities
2083 elsif Is_Floating_Point_Type (S_Typ) then
2084 if Is_Constrained (S_Typ) then
2085 Enable_Range_Check (Expr);
2088 -- For all other cases we enable a range check unconditionally
2091 Enable_Range_Check (Expr);
2094 end Apply_Scalar_Range_Check;
2096 ----------------------------------
2097 -- Apply_Selected_Length_Checks --
2098 ----------------------------------
2100 procedure Apply_Selected_Length_Checks
2102 Target_Typ : Entity_Id;
2103 Source_Typ : Entity_Id;
2104 Do_Static : Boolean)
2107 R_Result : Check_Result;
2110 Loc : constant Source_Ptr := Sloc (Ck_Node);
2111 Checks_On : constant Boolean :=
2112 (not Index_Checks_Suppressed (Target_Typ))
2114 (not Length_Checks_Suppressed (Target_Typ));
2117 if not Expander_Active then
2122 Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty);
2124 for J in 1 .. 2 loop
2125 R_Cno := R_Result (J);
2126 exit when No (R_Cno);
2128 -- A length check may mention an Itype which is attached to a
2129 -- subsequent node. At the top level in a package this can cause
2130 -- an order-of-elaboration problem, so we make sure that the itype
2131 -- is referenced now.
2133 if Ekind (Current_Scope) = E_Package
2134 and then Is_Compilation_Unit (Current_Scope)
2136 Ensure_Defined (Target_Typ, Ck_Node);
2138 if Present (Source_Typ) then
2139 Ensure_Defined (Source_Typ, Ck_Node);
2141 elsif Is_Itype (Etype (Ck_Node)) then
2142 Ensure_Defined (Etype (Ck_Node), Ck_Node);
2146 -- If the item is a conditional raise of constraint error, then have
2147 -- a look at what check is being performed and ???
2149 if Nkind (R_Cno) = N_Raise_Constraint_Error
2150 and then Present (Condition (R_Cno))
2152 Cond := Condition (R_Cno);
2154 -- Case where node does not now have a dynamic check
2156 if not Has_Dynamic_Length_Check (Ck_Node) then
2158 -- If checks are on, just insert the check
2161 Insert_Action (Ck_Node, R_Cno);
2163 if not Do_Static then
2164 Set_Has_Dynamic_Length_Check (Ck_Node);
2167 -- If checks are off, then analyze the length check after
2168 -- temporarily attaching it to the tree in case the relevant
2169 -- condition can be evaluated at compile time. We still want a
2170 -- compile time warning in this case.
2173 Set_Parent (R_Cno, Ck_Node);
2178 -- Output a warning if the condition is known to be True
2180 if Is_Entity_Name (Cond)
2181 and then Entity (Cond) = Standard_True
2183 Apply_Compile_Time_Constraint_Error
2184 (Ck_Node, "wrong length for array of}?",
2185 CE_Length_Check_Failed,
2189 -- If we were only doing a static check, or if checks are not
2190 -- on, then we want to delete the check, since it is not needed.
2191 -- We do this by replacing the if statement by a null statement
2193 elsif Do_Static or else not Checks_On then
2194 Remove_Warning_Messages (R_Cno);
2195 Rewrite (R_Cno, Make_Null_Statement (Loc));
2199 Install_Static_Check (R_Cno, Loc);
2202 end Apply_Selected_Length_Checks;
2204 ---------------------------------
2205 -- Apply_Selected_Range_Checks --
2206 ---------------------------------
2208 procedure Apply_Selected_Range_Checks
2210 Target_Typ : Entity_Id;
2211 Source_Typ : Entity_Id;
2212 Do_Static : Boolean)
2215 R_Result : Check_Result;
2218 Loc : constant Source_Ptr := Sloc (Ck_Node);
2219 Checks_On : constant Boolean :=
2220 (not Index_Checks_Suppressed (Target_Typ))
2222 (not Range_Checks_Suppressed (Target_Typ));
2225 if not Expander_Active or else not Checks_On then
2230 Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty);
2232 for J in 1 .. 2 loop
2234 R_Cno := R_Result (J);
2235 exit when No (R_Cno);
2237 -- If the item is a conditional raise of constraint error, then have
2238 -- a look at what check is being performed and ???
2240 if Nkind (R_Cno) = N_Raise_Constraint_Error
2241 and then Present (Condition (R_Cno))
2243 Cond := Condition (R_Cno);
2245 if not Has_Dynamic_Range_Check (Ck_Node) then
2246 Insert_Action (Ck_Node, R_Cno);
2248 if not Do_Static then
2249 Set_Has_Dynamic_Range_Check (Ck_Node);
2253 -- Output a warning if the condition is known to be True
2255 if Is_Entity_Name (Cond)
2256 and then Entity (Cond) = Standard_True
2258 -- Since an N_Range is technically not an expression, we have
2259 -- to set one of the bounds to C_E and then just flag the
2260 -- N_Range. The warning message will point to the lower bound
2261 -- and complain about a range, which seems OK.
2263 if Nkind (Ck_Node) = N_Range then
2264 Apply_Compile_Time_Constraint_Error
2265 (Low_Bound (Ck_Node), "static range out of bounds of}?",
2266 CE_Range_Check_Failed,
2270 Set_Raises_Constraint_Error (Ck_Node);
2273 Apply_Compile_Time_Constraint_Error
2274 (Ck_Node, "static value out of range of}?",
2275 CE_Range_Check_Failed,
2280 -- If we were only doing a static check, or if checks are not
2281 -- on, then we want to delete the check, since it is not needed.
2282 -- We do this by replacing the if statement by a null statement
2284 elsif Do_Static or else not Checks_On then
2285 Remove_Warning_Messages (R_Cno);
2286 Rewrite (R_Cno, Make_Null_Statement (Loc));
2290 Install_Static_Check (R_Cno, Loc);
2293 end Apply_Selected_Range_Checks;
2295 -------------------------------
2296 -- Apply_Static_Length_Check --
2297 -------------------------------
2299 procedure Apply_Static_Length_Check
2301 Target_Typ : Entity_Id;
2302 Source_Typ : Entity_Id := Empty)
2305 Apply_Selected_Length_Checks
2306 (Expr, Target_Typ, Source_Typ, Do_Static => True);
2307 end Apply_Static_Length_Check;
2309 -------------------------------------
2310 -- Apply_Subscript_Validity_Checks --
2311 -------------------------------------
2313 procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is
2317 pragma Assert (Nkind (Expr) = N_Indexed_Component);
2319 -- Loop through subscripts
2321 Sub := First (Expressions (Expr));
2322 while Present (Sub) loop
2324 -- Check one subscript. Note that we do not worry about enumeration
2325 -- type with holes, since we will convert the value to a Pos value
2326 -- for the subscript, and that convert will do the necessary validity
2329 Ensure_Valid (Sub, Holes_OK => True);
2331 -- Move to next subscript
2335 end Apply_Subscript_Validity_Checks;
2337 ----------------------------------
2338 -- Apply_Type_Conversion_Checks --
2339 ----------------------------------
2341 procedure Apply_Type_Conversion_Checks (N : Node_Id) is
2342 Target_Type : constant Entity_Id := Etype (N);
2343 Target_Base : constant Entity_Id := Base_Type (Target_Type);
2344 Expr : constant Node_Id := Expression (N);
2346 Expr_Type : constant Entity_Id := Underlying_Type (Etype (Expr));
2347 -- Note: if Etype (Expr) is a private type without discriminants, its
2348 -- full view might have discriminants with defaults, so we need the
2349 -- full view here to retrieve the constraints.
2352 if Inside_A_Generic then
2355 -- Skip these checks if serious errors detected, there are some nasty
2356 -- situations of incomplete trees that blow things up.
2358 elsif Serious_Errors_Detected > 0 then
2361 -- Scalar type conversions of the form Target_Type (Expr) require a
2362 -- range check if we cannot be sure that Expr is in the base type of
2363 -- Target_Typ and also that Expr is in the range of Target_Typ. These
2364 -- are not quite the same condition from an implementation point of
2365 -- view, but clearly the second includes the first.
2367 elsif Is_Scalar_Type (Target_Type) then
2369 Conv_OK : constant Boolean := Conversion_OK (N);
2370 -- If the Conversion_OK flag on the type conversion is set and no
2371 -- floating point type is involved in the type conversion then
2372 -- fixed point values must be read as integral values.
2374 Float_To_Int : constant Boolean :=
2375 Is_Floating_Point_Type (Expr_Type)
2376 and then Is_Integer_Type (Target_Type);
2379 if not Overflow_Checks_Suppressed (Target_Base)
2381 In_Subrange_Of (Expr_Type, Target_Base, Fixed_Int => Conv_OK)
2382 and then not Float_To_Int
2384 Activate_Overflow_Check (N);
2387 if not Range_Checks_Suppressed (Target_Type)
2388 and then not Range_Checks_Suppressed (Expr_Type)
2390 if Float_To_Int then
2391 Apply_Float_Conversion_Check (Expr, Target_Type);
2393 Apply_Scalar_Range_Check
2394 (Expr, Target_Type, Fixed_Int => Conv_OK);
2399 elsif Comes_From_Source (N)
2400 and then not Discriminant_Checks_Suppressed (Target_Type)
2401 and then Is_Record_Type (Target_Type)
2402 and then Is_Derived_Type (Target_Type)
2403 and then not Is_Tagged_Type (Target_Type)
2404 and then not Is_Constrained (Target_Type)
2405 and then Present (Stored_Constraint (Target_Type))
2407 -- An unconstrained derived type may have inherited discriminant.
2408 -- Build an actual discriminant constraint list using the stored
2409 -- constraint, to verify that the expression of the parent type
2410 -- satisfies the constraints imposed by the (unconstrained!)
2411 -- derived type. This applies to value conversions, not to view
2412 -- conversions of tagged types.
2415 Loc : constant Source_Ptr := Sloc (N);
2417 Constraint : Elmt_Id;
2418 Discr_Value : Node_Id;
2421 New_Constraints : constant Elist_Id := New_Elmt_List;
2422 Old_Constraints : constant Elist_Id :=
2423 Discriminant_Constraint (Expr_Type);
2426 Constraint := First_Elmt (Stored_Constraint (Target_Type));
2427 while Present (Constraint) loop
2428 Discr_Value := Node (Constraint);
2430 if Is_Entity_Name (Discr_Value)
2431 and then Ekind (Entity (Discr_Value)) = E_Discriminant
2433 Discr := Corresponding_Discriminant (Entity (Discr_Value));
2436 and then Scope (Discr) = Base_Type (Expr_Type)
2438 -- Parent is constrained by new discriminant. Obtain
2439 -- Value of original discriminant in expression. If the
2440 -- new discriminant has been used to constrain more than
2441 -- one of the stored discriminants, this will provide the
2442 -- required consistency check.
2445 (Make_Selected_Component (Loc,
2447 Duplicate_Subexpr_No_Checks
2448 (Expr, Name_Req => True),
2450 Make_Identifier (Loc, Chars (Discr))),
2454 -- Discriminant of more remote ancestor ???
2459 -- Derived type definition has an explicit value for this
2460 -- stored discriminant.
2464 (Duplicate_Subexpr_No_Checks (Discr_Value),
2468 Next_Elmt (Constraint);
2471 -- Use the unconstrained expression type to retrieve the
2472 -- discriminants of the parent, and apply momentarily the
2473 -- discriminant constraint synthesized above.
2475 Set_Discriminant_Constraint (Expr_Type, New_Constraints);
2476 Cond := Build_Discriminant_Checks (Expr, Expr_Type);
2477 Set_Discriminant_Constraint (Expr_Type, Old_Constraints);
2480 Make_Raise_Constraint_Error (Loc,
2482 Reason => CE_Discriminant_Check_Failed));
2485 -- For arrays, conversions are applied during expansion, to take into
2486 -- accounts changes of representation. The checks become range checks on
2487 -- the base type or length checks on the subtype, depending on whether
2488 -- the target type is unconstrained or constrained.
2493 end Apply_Type_Conversion_Checks;
2495 ----------------------------------------------
2496 -- Apply_Universal_Integer_Attribute_Checks --
2497 ----------------------------------------------
2499 procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is
2500 Loc : constant Source_Ptr := Sloc (N);
2501 Typ : constant Entity_Id := Etype (N);
2504 if Inside_A_Generic then
2507 -- Nothing to do if checks are suppressed
2509 elsif Range_Checks_Suppressed (Typ)
2510 and then Overflow_Checks_Suppressed (Typ)
2514 -- Nothing to do if the attribute does not come from source. The
2515 -- internal attributes we generate of this type do not need checks,
2516 -- and furthermore the attempt to check them causes some circular
2517 -- elaboration orders when dealing with packed types.
2519 elsif not Comes_From_Source (N) then
2522 -- If the prefix is a selected component that depends on a discriminant
2523 -- the check may improperly expose a discriminant instead of using
2524 -- the bounds of the object itself. Set the type of the attribute to
2525 -- the base type of the context, so that a check will be imposed when
2526 -- needed (e.g. if the node appears as an index).
2528 elsif Nkind (Prefix (N)) = N_Selected_Component
2529 and then Ekind (Typ) = E_Signed_Integer_Subtype
2530 and then Depends_On_Discriminant (Scalar_Range (Typ))
2532 Set_Etype (N, Base_Type (Typ));
2534 -- Otherwise, replace the attribute node with a type conversion node
2535 -- whose expression is the attribute, retyped to universal integer, and
2536 -- whose subtype mark is the target type. The call to analyze this
2537 -- conversion will set range and overflow checks as required for proper
2538 -- detection of an out of range value.
2541 Set_Etype (N, Universal_Integer);
2542 Set_Analyzed (N, True);
2545 Make_Type_Conversion (Loc,
2546 Subtype_Mark => New_Occurrence_Of (Typ, Loc),
2547 Expression => Relocate_Node (N)));
2549 Analyze_And_Resolve (N, Typ);
2552 end Apply_Universal_Integer_Attribute_Checks;
2554 -------------------------------
2555 -- Build_Discriminant_Checks --
2556 -------------------------------
2558 function Build_Discriminant_Checks
2560 T_Typ : Entity_Id) return Node_Id
2562 Loc : constant Source_Ptr := Sloc (N);
2565 Disc_Ent : Entity_Id;
2569 function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id;
2571 ----------------------------------
2572 -- Aggregate_Discriminant_Value --
2573 ----------------------------------
2575 function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id is
2579 -- The aggregate has been normalized with named associations. We use
2580 -- the Chars field to locate the discriminant to take into account
2581 -- discriminants in derived types, which carry the same name as those
2584 Assoc := First (Component_Associations (N));
2585 while Present (Assoc) loop
2586 if Chars (First (Choices (Assoc))) = Chars (Disc) then
2587 return Expression (Assoc);
2593 -- Discriminant must have been found in the loop above
2595 raise Program_Error;
2596 end Aggregate_Discriminant_Val;
2598 -- Start of processing for Build_Discriminant_Checks
2601 -- Loop through discriminants evolving the condition
2604 Disc := First_Elmt (Discriminant_Constraint (T_Typ));
2606 -- For a fully private type, use the discriminants of the parent type
2608 if Is_Private_Type (T_Typ)
2609 and then No (Full_View (T_Typ))
2611 Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ)));
2613 Disc_Ent := First_Discriminant (T_Typ);
2616 while Present (Disc) loop
2617 Dval := Node (Disc);
2619 if Nkind (Dval) = N_Identifier
2620 and then Ekind (Entity (Dval)) = E_Discriminant
2622 Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc);
2624 Dval := Duplicate_Subexpr_No_Checks (Dval);
2627 -- If we have an Unchecked_Union node, we can infer the discriminants
2630 if Is_Unchecked_Union (Base_Type (T_Typ)) then
2632 Get_Discriminant_Value (
2633 First_Discriminant (T_Typ),
2635 Stored_Constraint (T_Typ)));
2637 elsif Nkind (N) = N_Aggregate then
2639 Duplicate_Subexpr_No_Checks
2640 (Aggregate_Discriminant_Val (Disc_Ent));
2644 Make_Selected_Component (Loc,
2646 Duplicate_Subexpr_No_Checks (N, Name_Req => True),
2648 Make_Identifier (Loc, Chars (Disc_Ent)));
2650 Set_Is_In_Discriminant_Check (Dref);
2653 Evolve_Or_Else (Cond,
2656 Right_Opnd => Dval));
2659 Next_Discriminant (Disc_Ent);
2663 end Build_Discriminant_Checks;
2669 function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean is
2677 -- Always check if not simple entity
2679 if Nkind (Nod) not in N_Has_Entity
2680 or else not Comes_From_Source (Nod)
2685 -- Look up tree for short circuit
2692 -- Done if out of subexpression (note that we allow generated stuff
2693 -- such as itype declarations in this context, to keep the loop going
2694 -- since we may well have generated such stuff in complex situations.
2695 -- Also done if no parent (probably an error condition, but no point
2696 -- in behaving nasty if we find it!)
2699 or else (K not in N_Subexpr and then Comes_From_Source (P))
2703 -- Or/Or Else case, where test is part of the right operand, or is
2704 -- part of one of the actions associated with the right operand, and
2705 -- the left operand is an equality test.
2707 elsif K = N_Op_Or then
2708 exit when N = Right_Opnd (P)
2709 and then Nkind (Left_Opnd (P)) = N_Op_Eq;
2711 elsif K = N_Or_Else then
2712 exit when (N = Right_Opnd (P)
2715 and then List_Containing (N) = Actions (P)))
2716 and then Nkind (Left_Opnd (P)) = N_Op_Eq;
2718 -- Similar test for the And/And then case, where the left operand
2719 -- is an inequality test.
2721 elsif K = N_Op_And then
2722 exit when N = Right_Opnd (P)
2723 and then Nkind (Left_Opnd (P)) = N_Op_Ne;
2725 elsif K = N_And_Then then
2726 exit when (N = Right_Opnd (P)
2729 and then List_Containing (N) = Actions (P)))
2730 and then Nkind (Left_Opnd (P)) = N_Op_Ne;
2736 -- If we fall through the loop, then we have a conditional with an
2737 -- appropriate test as its left operand. So test further.
2740 R := Right_Opnd (L);
2743 -- Left operand of test must match original variable
2745 if Nkind (L) not in N_Has_Entity
2746 or else Entity (L) /= Entity (Nod)
2751 -- Right operand of test must be key value (zero or null)
2754 when Access_Check =>
2755 if not Known_Null (R) then
2759 when Division_Check =>
2760 if not Compile_Time_Known_Value (R)
2761 or else Expr_Value (R) /= Uint_0
2767 raise Program_Error;
2770 -- Here we have the optimizable case, warn if not short-circuited
2772 if K = N_Op_And or else K = N_Op_Or then
2774 when Access_Check =>
2776 ("Constraint_Error may be raised (access check)?",
2778 when Division_Check =>
2780 ("Constraint_Error may be raised (zero divide)?",
2784 raise Program_Error;
2787 if K = N_Op_And then
2788 Error_Msg_N -- CODEFIX
2789 ("use `AND THEN` instead of AND?", P);
2791 Error_Msg_N -- CODEFIX
2792 ("use `OR ELSE` instead of OR?", P);
2795 -- If not short-circuited, we need the check
2799 -- If short-circuited, we can omit the check
2806 -----------------------------------
2807 -- Check_Valid_Lvalue_Subscripts --
2808 -----------------------------------
2810 procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is
2812 -- Skip this if range checks are suppressed
2814 if Range_Checks_Suppressed (Etype (Expr)) then
2817 -- Only do this check for expressions that come from source. We assume
2818 -- that expander generated assignments explicitly include any necessary
2819 -- checks. Note that this is not just an optimization, it avoids
2820 -- infinite recursions!
2822 elsif not Comes_From_Source (Expr) then
2825 -- For a selected component, check the prefix
2827 elsif Nkind (Expr) = N_Selected_Component then
2828 Check_Valid_Lvalue_Subscripts (Prefix (Expr));
2831 -- Case of indexed component
2833 elsif Nkind (Expr) = N_Indexed_Component then
2834 Apply_Subscript_Validity_Checks (Expr);
2836 -- Prefix may itself be or contain an indexed component, and these
2837 -- subscripts need checking as well.
2839 Check_Valid_Lvalue_Subscripts (Prefix (Expr));
2841 end Check_Valid_Lvalue_Subscripts;
2843 ----------------------------------
2844 -- Null_Exclusion_Static_Checks --
2845 ----------------------------------
2847 procedure Null_Exclusion_Static_Checks (N : Node_Id) is
2848 Error_Node : Node_Id;
2850 Has_Null : constant Boolean := Has_Null_Exclusion (N);
2851 K : constant Node_Kind := Nkind (N);
2856 (K = N_Component_Declaration
2857 or else K = N_Discriminant_Specification
2858 or else K = N_Function_Specification
2859 or else K = N_Object_Declaration
2860 or else K = N_Parameter_Specification);
2862 if K = N_Function_Specification then
2863 Typ := Etype (Defining_Entity (N));
2865 Typ := Etype (Defining_Identifier (N));
2869 when N_Component_Declaration =>
2870 if Present (Access_Definition (Component_Definition (N))) then
2871 Error_Node := Component_Definition (N);
2873 Error_Node := Subtype_Indication (Component_Definition (N));
2876 when N_Discriminant_Specification =>
2877 Error_Node := Discriminant_Type (N);
2879 when N_Function_Specification =>
2880 Error_Node := Result_Definition (N);
2882 when N_Object_Declaration =>
2883 Error_Node := Object_Definition (N);
2885 when N_Parameter_Specification =>
2886 Error_Node := Parameter_Type (N);
2889 raise Program_Error;
2894 -- Enforce legality rule 3.10 (13): A null exclusion can only be
2895 -- applied to an access [sub]type.
2897 if not Is_Access_Type (Typ) then
2899 ("`NOT NULL` allowed only for an access type", Error_Node);
2901 -- Enforce legality rule RM 3.10(14/1): A null exclusion can only
2902 -- be applied to a [sub]type that does not exclude null already.
2904 elsif Can_Never_Be_Null (Typ)
2905 and then Comes_From_Source (Typ)
2908 ("`NOT NULL` not allowed (& already excludes null)",
2913 -- Check that null-excluding objects are always initialized, except for
2914 -- deferred constants, for which the expression will appear in the full
2917 if K = N_Object_Declaration
2918 and then No (Expression (N))
2919 and then not Constant_Present (N)
2920 and then not No_Initialization (N)
2922 -- Add an expression that assigns null. This node is needed by
2923 -- Apply_Compile_Time_Constraint_Error, which will replace this with
2924 -- a Constraint_Error node.
2926 Set_Expression (N, Make_Null (Sloc (N)));
2927 Set_Etype (Expression (N), Etype (Defining_Identifier (N)));
2929 Apply_Compile_Time_Constraint_Error
2930 (N => Expression (N),
2931 Msg => "(Ada 2005) null-excluding objects must be initialized?",
2932 Reason => CE_Null_Not_Allowed);
2935 -- Check that a null-excluding component, formal or object is not being
2936 -- assigned a null value. Otherwise generate a warning message and
2937 -- replace Expression (N) by an N_Constraint_Error node.
2939 if K /= N_Function_Specification then
2940 Expr := Expression (N);
2942 if Present (Expr) and then Known_Null (Expr) then
2944 when N_Component_Declaration |
2945 N_Discriminant_Specification =>
2946 Apply_Compile_Time_Constraint_Error
2948 Msg => "(Ada 2005) null not allowed " &
2949 "in null-excluding components?",
2950 Reason => CE_Null_Not_Allowed);
2952 when N_Object_Declaration =>
2953 Apply_Compile_Time_Constraint_Error
2955 Msg => "(Ada 2005) null not allowed " &
2956 "in null-excluding objects?",
2957 Reason => CE_Null_Not_Allowed);
2959 when N_Parameter_Specification =>
2960 Apply_Compile_Time_Constraint_Error
2962 Msg => "(Ada 2005) null not allowed " &
2963 "in null-excluding formals?",
2964 Reason => CE_Null_Not_Allowed);
2971 end Null_Exclusion_Static_Checks;
2973 ----------------------------------
2974 -- Conditional_Statements_Begin --
2975 ----------------------------------
2977 procedure Conditional_Statements_Begin is
2979 Saved_Checks_TOS := Saved_Checks_TOS + 1;
2981 -- If stack overflows, kill all checks, that way we know to simply reset
2982 -- the number of saved checks to zero on return. This should never occur
2985 if Saved_Checks_TOS > Saved_Checks_Stack'Last then
2988 -- In the normal case, we just make a new stack entry saving the current
2989 -- number of saved checks for a later restore.
2992 Saved_Checks_Stack (Saved_Checks_TOS) := Num_Saved_Checks;
2994 if Debug_Flag_CC then
2995 w ("Conditional_Statements_Begin: Num_Saved_Checks = ",
2999 end Conditional_Statements_Begin;
3001 --------------------------------
3002 -- Conditional_Statements_End --
3003 --------------------------------
3005 procedure Conditional_Statements_End is
3007 pragma Assert (Saved_Checks_TOS > 0);
3009 -- If the saved checks stack overflowed, then we killed all checks, so
3010 -- setting the number of saved checks back to zero is correct. This
3011 -- should never occur in practice.
3013 if Saved_Checks_TOS > Saved_Checks_Stack'Last then
3014 Num_Saved_Checks := 0;
3016 -- In the normal case, restore the number of saved checks from the top
3020 Num_Saved_Checks := Saved_Checks_Stack (Saved_Checks_TOS);
3021 if Debug_Flag_CC then
3022 w ("Conditional_Statements_End: Num_Saved_Checks = ",
3027 Saved_Checks_TOS := Saved_Checks_TOS - 1;
3028 end Conditional_Statements_End;
3030 ---------------------
3031 -- Determine_Range --
3032 ---------------------
3034 Cache_Size : constant := 2 ** 10;
3035 type Cache_Index is range 0 .. Cache_Size - 1;
3036 -- Determine size of below cache (power of 2 is more efficient!)
3038 Determine_Range_Cache_N : array (Cache_Index) of Node_Id;
3039 Determine_Range_Cache_V : array (Cache_Index) of Boolean;
3040 Determine_Range_Cache_Lo : array (Cache_Index) of Uint;
3041 Determine_Range_Cache_Hi : array (Cache_Index) of Uint;
3042 -- The above arrays are used to implement a small direct cache for
3043 -- Determine_Range calls. Because of the way Determine_Range recursively
3044 -- traces subexpressions, and because overflow checking calls the routine
3045 -- on the way up the tree, a quadratic behavior can otherwise be
3046 -- encountered in large expressions. The cache entry for node N is stored
3047 -- in the (N mod Cache_Size) entry, and can be validated by checking the
3048 -- actual node value stored there. The Range_Cache_V array records the
3049 -- setting of Assume_Valid for the cache entry.
3051 procedure Determine_Range
3056 Assume_Valid : Boolean := False)
3058 Typ : Entity_Id := Etype (N);
3059 -- Type to use, may get reset to base type for possibly invalid entity
3063 -- Lo and Hi bounds of left operand
3067 -- Lo and Hi bounds of right (or only) operand
3070 -- Temp variable used to hold a bound node
3073 -- High bound of base type of expression
3077 -- Refined values for low and high bounds, after tightening
3080 -- Used in lower level calls to indicate if call succeeded
3082 Cindex : Cache_Index;
3083 -- Used to search cache
3085 function OK_Operands return Boolean;
3086 -- Used for binary operators. Determines the ranges of the left and
3087 -- right operands, and if they are both OK, returns True, and puts
3088 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left.
3094 function OK_Operands return Boolean is
3097 (Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid);
3104 (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid);
3108 -- Start of processing for Determine_Range
3111 -- For temporary constants internally generated to remove side effects
3112 -- we must use the corresponding expression to determine the range of
3115 if Is_Entity_Name (N)
3116 and then Nkind (Parent (Entity (N))) = N_Object_Declaration
3117 and then Ekind (Entity (N)) = E_Constant
3118 and then Is_Internal_Name (Chars (Entity (N)))
3121 (Expression (Parent (Entity (N))), OK, Lo, Hi, Assume_Valid);
3125 -- Prevent junk warnings by initializing range variables
3132 -- If type is not defined, we can't determine its range
3136 -- We don't deal with anything except discrete types
3138 or else not Is_Discrete_Type (Typ)
3140 -- Ignore type for which an error has been posted, since range in
3141 -- this case may well be a bogosity deriving from the error. Also
3142 -- ignore if error posted on the reference node.
3144 or else Error_Posted (N) or else Error_Posted (Typ)
3150 -- For all other cases, we can determine the range
3154 -- If value is compile time known, then the possible range is the one
3155 -- value that we know this expression definitely has!
3157 if Compile_Time_Known_Value (N) then
3158 Lo := Expr_Value (N);
3163 -- Return if already in the cache
3165 Cindex := Cache_Index (N mod Cache_Size);
3167 if Determine_Range_Cache_N (Cindex) = N
3169 Determine_Range_Cache_V (Cindex) = Assume_Valid
3171 Lo := Determine_Range_Cache_Lo (Cindex);
3172 Hi := Determine_Range_Cache_Hi (Cindex);
3176 -- Otherwise, start by finding the bounds of the type of the expression,
3177 -- the value cannot be outside this range (if it is, then we have an
3178 -- overflow situation, which is a separate check, we are talking here
3179 -- only about the expression value).
3181 -- First a check, never try to find the bounds of a generic type, since
3182 -- these bounds are always junk values, and it is only valid to look at
3183 -- the bounds in an instance.
3185 if Is_Generic_Type (Typ) then
3190 -- First step, change to use base type unless we know the value is valid
3192 if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N)))
3193 or else Assume_No_Invalid_Values
3194 or else Assume_Valid
3198 Typ := Underlying_Type (Base_Type (Typ));
3201 -- We use the actual bound unless it is dynamic, in which case use the
3202 -- corresponding base type bound if possible. If we can't get a bound
3203 -- then we figure we can't determine the range (a peculiar case, that
3204 -- perhaps cannot happen, but there is no point in bombing in this
3205 -- optimization circuit.
3207 -- First the low bound
3209 Bound := Type_Low_Bound (Typ);
3211 if Compile_Time_Known_Value (Bound) then
3212 Lo := Expr_Value (Bound);
3214 elsif Compile_Time_Known_Value (Type_Low_Bound (Base_Type (Typ))) then
3215 Lo := Expr_Value (Type_Low_Bound (Base_Type (Typ)));
3222 -- Now the high bound
3224 Bound := Type_High_Bound (Typ);
3226 -- We need the high bound of the base type later on, and this should
3227 -- always be compile time known. Again, it is not clear that this
3228 -- can ever be false, but no point in bombing.
3230 if Compile_Time_Known_Value (Type_High_Bound (Base_Type (Typ))) then
3231 Hbound := Expr_Value (Type_High_Bound (Base_Type (Typ)));
3239 -- If we have a static subtype, then that may have a tighter bound so
3240 -- use the upper bound of the subtype instead in this case.
3242 if Compile_Time_Known_Value (Bound) then
3243 Hi := Expr_Value (Bound);
3246 -- We may be able to refine this value in certain situations. If any
3247 -- refinement is possible, then Lor and Hir are set to possibly tighter
3248 -- bounds, and OK1 is set to True.
3252 -- For unary plus, result is limited by range of operand
3256 (Right_Opnd (N), OK1, Lor, Hir, Assume_Valid);
3258 -- For unary minus, determine range of operand, and negate it
3262 (Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid);
3269 -- For binary addition, get range of each operand and do the
3270 -- addition to get the result range.
3274 Lor := Lo_Left + Lo_Right;
3275 Hir := Hi_Left + Hi_Right;
3278 -- Division is tricky. The only case we consider is where the right
3279 -- operand is a positive constant, and in this case we simply divide
3280 -- the bounds of the left operand
3284 if Lo_Right = Hi_Right
3285 and then Lo_Right > 0
3287 Lor := Lo_Left / Lo_Right;
3288 Hir := Hi_Left / Lo_Right;
3295 -- For binary subtraction, get range of each operand and do the worst
3296 -- case subtraction to get the result range.
3298 when N_Op_Subtract =>
3300 Lor := Lo_Left - Hi_Right;
3301 Hir := Hi_Left - Lo_Right;
3304 -- For MOD, if right operand is a positive constant, then result must
3305 -- be in the allowable range of mod results.
3309 if Lo_Right = Hi_Right
3310 and then Lo_Right /= 0
3312 if Lo_Right > 0 then
3314 Hir := Lo_Right - 1;
3316 else -- Lo_Right < 0
3317 Lor := Lo_Right + 1;
3326 -- For REM, if right operand is a positive constant, then result must
3327 -- be in the allowable range of mod results.
3331 if Lo_Right = Hi_Right
3332 and then Lo_Right /= 0
3335 Dval : constant Uint := (abs Lo_Right) - 1;
3338 -- The sign of the result depends on the sign of the
3339 -- dividend (but not on the sign of the divisor, hence
3340 -- the abs operation above).
3360 -- Attribute reference cases
3362 when N_Attribute_Reference =>
3363 case Attribute_Name (N) is
3365 -- For Pos/Val attributes, we can refine the range using the
3366 -- possible range of values of the attribute expression.
3368 when Name_Pos | Name_Val =>
3370 (First (Expressions (N)), OK1, Lor, Hir, Assume_Valid);
3372 -- For Length attribute, use the bounds of the corresponding
3373 -- index type to refine the range.
3377 Atyp : Entity_Id := Etype (Prefix (N));
3385 if Is_Access_Type (Atyp) then
3386 Atyp := Designated_Type (Atyp);
3389 -- For string literal, we know exact value
3391 if Ekind (Atyp) = E_String_Literal_Subtype then
3393 Lo := String_Literal_Length (Atyp);
3394 Hi := String_Literal_Length (Atyp);
3398 -- Otherwise check for expression given
3400 if No (Expressions (N)) then
3404 UI_To_Int (Expr_Value (First (Expressions (N))));
3407 Indx := First_Index (Atyp);
3408 for J in 2 .. Inum loop
3409 Indx := Next_Index (Indx);
3412 -- If the index type is a formal type or derived from
3413 -- one, the bounds are not static.
3415 if Is_Generic_Type (Root_Type (Etype (Indx))) then
3421 (Type_Low_Bound (Etype (Indx)), OK1, LL, LU,
3426 (Type_High_Bound (Etype (Indx)), OK1, UL, UU,
3431 -- The maximum value for Length is the biggest
3432 -- possible gap between the values of the bounds.
3433 -- But of course, this value cannot be negative.
3435 Hir := UI_Max (Uint_0, UU - LL + 1);
3437 -- For constrained arrays, the minimum value for
3438 -- Length is taken from the actual value of the
3439 -- bounds, since the index will be exactly of this
3442 if Is_Constrained (Atyp) then
3443 Lor := UI_Max (Uint_0, UL - LU + 1);
3445 -- For an unconstrained array, the minimum value
3446 -- for length is always zero.
3455 -- No special handling for other attributes
3456 -- Probably more opportunities exist here???
3463 -- For type conversion from one discrete type to another, we can
3464 -- refine the range using the converted value.
3466 when N_Type_Conversion =>
3467 Determine_Range (Expression (N), OK1, Lor, Hir, Assume_Valid);
3469 -- Nothing special to do for all other expression kinds
3477 -- At this stage, if OK1 is true, then we know that the actual result of
3478 -- the computed expression is in the range Lor .. Hir. We can use this
3479 -- to restrict the possible range of results.
3481 -- If one of the computed bounds is outside the range of the base type,
3482 -- the expression may raise an exception and we better indicate that
3483 -- the evaluation has failed, at least if checks are enabled.
3485 if Enable_Overflow_Checks
3486 and then not Is_Entity_Name (N)
3487 and then (Lor < Lo or else Hir > Hi)
3495 -- If the refined value of the low bound is greater than the type
3496 -- high bound, then reset it to the more restrictive value. However,
3497 -- we do NOT do this for the case of a modular type where the
3498 -- possible upper bound on the value is above the base type high
3499 -- bound, because that means the result could wrap.
3502 and then not (Is_Modular_Integer_Type (Typ) and then Hir > Hbound)
3507 -- Similarly, if the refined value of the high bound is less than the
3508 -- value so far, then reset it to the more restrictive value. Again,
3509 -- we do not do this if the refined low bound is negative for a
3510 -- modular type, since this would wrap.
3513 and then not (Is_Modular_Integer_Type (Typ) and then Lor < Uint_0)
3519 -- Set cache entry for future call and we are all done
3521 Determine_Range_Cache_N (Cindex) := N;
3522 Determine_Range_Cache_V (Cindex) := Assume_Valid;
3523 Determine_Range_Cache_Lo (Cindex) := Lo;
3524 Determine_Range_Cache_Hi (Cindex) := Hi;
3527 -- If any exception occurs, it means that we have some bug in the compiler,
3528 -- possibly triggered by a previous error, or by some unforeseen peculiar
3529 -- occurrence. However, this is only an optimization attempt, so there is
3530 -- really no point in crashing the compiler. Instead we just decide, too
3531 -- bad, we can't figure out a range in this case after all.
3536 -- Debug flag K disables this behavior (useful for debugging)
3538 if Debug_Flag_K then
3546 end Determine_Range;
3548 ------------------------------------
3549 -- Discriminant_Checks_Suppressed --
3550 ------------------------------------
3552 function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is
3555 if Is_Unchecked_Union (E) then
3557 elsif Checks_May_Be_Suppressed (E) then
3558 return Is_Check_Suppressed (E, Discriminant_Check);
3562 return Scope_Suppress (Discriminant_Check);
3563 end Discriminant_Checks_Suppressed;
3565 --------------------------------
3566 -- Division_Checks_Suppressed --
3567 --------------------------------
3569 function Division_Checks_Suppressed (E : Entity_Id) return Boolean is
3571 if Present (E) and then Checks_May_Be_Suppressed (E) then
3572 return Is_Check_Suppressed (E, Division_Check);
3574 return Scope_Suppress (Division_Check);
3576 end Division_Checks_Suppressed;
3578 -----------------------------------
3579 -- Elaboration_Checks_Suppressed --
3580 -----------------------------------
3582 function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is
3584 -- The complication in this routine is that if we are in the dynamic
3585 -- model of elaboration, we also check All_Checks, since All_Checks
3586 -- does not set Elaboration_Check explicitly.
3589 if Kill_Elaboration_Checks (E) then
3592 elsif Checks_May_Be_Suppressed (E) then
3593 if Is_Check_Suppressed (E, Elaboration_Check) then
3595 elsif Dynamic_Elaboration_Checks then
3596 return Is_Check_Suppressed (E, All_Checks);
3603 if Scope_Suppress (Elaboration_Check) then
3605 elsif Dynamic_Elaboration_Checks then
3606 return Scope_Suppress (All_Checks);
3610 end Elaboration_Checks_Suppressed;
3612 ---------------------------
3613 -- Enable_Overflow_Check --
3614 ---------------------------
3616 procedure Enable_Overflow_Check (N : Node_Id) is
3617 Typ : constant Entity_Id := Base_Type (Etype (N));
3626 if Debug_Flag_CC then
3627 w ("Enable_Overflow_Check for node ", Int (N));
3628 Write_Str (" Source location = ");
3633 -- No check if overflow checks suppressed for type of node
3635 if Present (Etype (N))
3636 and then Overflow_Checks_Suppressed (Etype (N))
3640 -- Nothing to do for unsigned integer types, which do not overflow
3642 elsif Is_Modular_Integer_Type (Typ) then
3645 -- Nothing to do if the range of the result is known OK. We skip this
3646 -- for conversions, since the caller already did the check, and in any
3647 -- case the condition for deleting the check for a type conversion is
3650 elsif Nkind (N) /= N_Type_Conversion then
3651 Determine_Range (N, OK, Lo, Hi, Assume_Valid => True);
3653 -- Note in the test below that we assume that the range is not OK
3654 -- if a bound of the range is equal to that of the type. That's not
3655 -- quite accurate but we do this for the following reasons:
3657 -- a) The way that Determine_Range works, it will typically report
3658 -- the bounds of the value as being equal to the bounds of the
3659 -- type, because it either can't tell anything more precise, or
3660 -- does not think it is worth the effort to be more precise.
3662 -- b) It is very unusual to have a situation in which this would
3663 -- generate an unnecessary overflow check (an example would be
3664 -- a subtype with a range 0 .. Integer'Last - 1 to which the
3665 -- literal value one is added).
3667 -- c) The alternative is a lot of special casing in this routine
3668 -- which would partially duplicate Determine_Range processing.
3671 and then Lo > Expr_Value (Type_Low_Bound (Typ))
3672 and then Hi < Expr_Value (Type_High_Bound (Typ))
3674 if Debug_Flag_CC then
3675 w ("No overflow check required");
3682 -- If not in optimizing mode, set flag and we are done. We are also done
3683 -- (and just set the flag) if the type is not a discrete type, since it
3684 -- is not worth the effort to eliminate checks for other than discrete
3685 -- types. In addition, we take this same path if we have stored the
3686 -- maximum number of checks possible already (a very unlikely situation,
3687 -- but we do not want to blow up!)
3689 if Optimization_Level = 0
3690 or else not Is_Discrete_Type (Etype (N))
3691 or else Num_Saved_Checks = Saved_Checks'Last
3693 Activate_Overflow_Check (N);
3695 if Debug_Flag_CC then
3696 w ("Optimization off");
3702 -- Otherwise evaluate and check the expression
3707 Target_Type => Empty,
3713 if Debug_Flag_CC then
3714 w ("Called Find_Check");
3718 w (" Check_Num = ", Chk);
3719 w (" Ent = ", Int (Ent));
3720 Write_Str (" Ofs = ");
3725 -- If check is not of form to optimize, then set flag and we are done
3728 Activate_Overflow_Check (N);
3732 -- If check is already performed, then return without setting flag
3735 if Debug_Flag_CC then
3736 w ("Check suppressed!");
3742 -- Here we will make a new entry for the new check
3744 Activate_Overflow_Check (N);
3745 Num_Saved_Checks := Num_Saved_Checks + 1;
3746 Saved_Checks (Num_Saved_Checks) :=
3751 Target_Type => Empty);
3753 if Debug_Flag_CC then
3754 w ("Make new entry, check number = ", Num_Saved_Checks);
3755 w (" Entity = ", Int (Ent));
3756 Write_Str (" Offset = ");
3758 w (" Check_Type = O");
3759 w (" Target_Type = Empty");
3762 -- If we get an exception, then something went wrong, probably because of
3763 -- an error in the structure of the tree due to an incorrect program. Or it
3764 -- may be a bug in the optimization circuit. In either case the safest
3765 -- thing is simply to set the check flag unconditionally.
3769 Activate_Overflow_Check (N);
3771 if Debug_Flag_CC then
3772 w (" exception occurred, overflow flag set");
3776 end Enable_Overflow_Check;
3778 ------------------------
3779 -- Enable_Range_Check --
3780 ------------------------
3782 procedure Enable_Range_Check (N : Node_Id) is
3791 -- Return if unchecked type conversion with range check killed. In this
3792 -- case we never set the flag (that's what Kill_Range_Check is about!)
3794 if Nkind (N) = N_Unchecked_Type_Conversion
3795 and then Kill_Range_Check (N)
3800 -- Do not set range check flag if parent is assignment statement or
3801 -- object declaration with Suppress_Assignment_Checks flag set
3803 if Nkind_In (Parent (N), N_Assignment_Statement, N_Object_Declaration)
3804 and then Suppress_Assignment_Checks (Parent (N))
3809 -- Check for various cases where we should suppress the range check
3811 -- No check if range checks suppressed for type of node
3813 if Present (Etype (N))
3814 and then Range_Checks_Suppressed (Etype (N))
3818 -- No check if node is an entity name, and range checks are suppressed
3819 -- for this entity, or for the type of this entity.
3821 elsif Is_Entity_Name (N)
3822 and then (Range_Checks_Suppressed (Entity (N))
3823 or else Range_Checks_Suppressed (Etype (Entity (N))))
3827 -- No checks if index of array, and index checks are suppressed for
3828 -- the array object or the type of the array.
3830 elsif Nkind (Parent (N)) = N_Indexed_Component then
3832 Pref : constant Node_Id := Prefix (Parent (N));
3834 if Is_Entity_Name (Pref)
3835 and then Index_Checks_Suppressed (Entity (Pref))
3838 elsif Index_Checks_Suppressed (Etype (Pref)) then
3844 -- Debug trace output
3846 if Debug_Flag_CC then
3847 w ("Enable_Range_Check for node ", Int (N));
3848 Write_Str (" Source location = ");
3853 -- If not in optimizing mode, set flag and we are done. We are also done
3854 -- (and just set the flag) if the type is not a discrete type, since it
3855 -- is not worth the effort to eliminate checks for other than discrete
3856 -- types. In addition, we take this same path if we have stored the
3857 -- maximum number of checks possible already (a very unlikely situation,
3858 -- but we do not want to blow up!)
3860 if Optimization_Level = 0
3861 or else No (Etype (N))
3862 or else not Is_Discrete_Type (Etype (N))
3863 or else Num_Saved_Checks = Saved_Checks'Last
3865 Activate_Range_Check (N);
3867 if Debug_Flag_CC then
3868 w ("Optimization off");
3874 -- Otherwise find out the target type
3878 -- For assignment, use left side subtype
3880 if Nkind (P) = N_Assignment_Statement
3881 and then Expression (P) = N
3883 Ttyp := Etype (Name (P));
3885 -- For indexed component, use subscript subtype
3887 elsif Nkind (P) = N_Indexed_Component then
3894 Atyp := Etype (Prefix (P));
3896 if Is_Access_Type (Atyp) then
3897 Atyp := Designated_Type (Atyp);
3899 -- If the prefix is an access to an unconstrained array,
3900 -- perform check unconditionally: it depends on the bounds of
3901 -- an object and we cannot currently recognize whether the test
3902 -- may be redundant.
3904 if not Is_Constrained (Atyp) then
3905 Activate_Range_Check (N);
3909 -- Ditto if the prefix is an explicit dereference whose designated
3910 -- type is unconstrained.
3912 elsif Nkind (Prefix (P)) = N_Explicit_Dereference
3913 and then not Is_Constrained (Atyp)
3915 Activate_Range_Check (N);
3919 Indx := First_Index (Atyp);
3920 Subs := First (Expressions (P));
3923 Ttyp := Etype (Indx);
3932 -- For now, ignore all other cases, they are not so interesting
3935 if Debug_Flag_CC then
3936 w (" target type not found, flag set");
3939 Activate_Range_Check (N);
3943 -- Evaluate and check the expression
3948 Target_Type => Ttyp,
3954 if Debug_Flag_CC then
3955 w ("Called Find_Check");
3956 w ("Target_Typ = ", Int (Ttyp));
3960 w (" Check_Num = ", Chk);
3961 w (" Ent = ", Int (Ent));
3962 Write_Str (" Ofs = ");
3967 -- If check is not of form to optimize, then set flag and we are done
3970 if Debug_Flag_CC then
3971 w (" expression not of optimizable type, flag set");
3974 Activate_Range_Check (N);
3978 -- If check is already performed, then return without setting flag
3981 if Debug_Flag_CC then
3982 w ("Check suppressed!");
3988 -- Here we will make a new entry for the new check
3990 Activate_Range_Check (N);
3991 Num_Saved_Checks := Num_Saved_Checks + 1;
3992 Saved_Checks (Num_Saved_Checks) :=
3997 Target_Type => Ttyp);
3999 if Debug_Flag_CC then
4000 w ("Make new entry, check number = ", Num_Saved_Checks);
4001 w (" Entity = ", Int (Ent));
4002 Write_Str (" Offset = ");
4004 w (" Check_Type = R");
4005 w (" Target_Type = ", Int (Ttyp));
4006 pg (Union_Id (Ttyp));
4009 -- If we get an exception, then something went wrong, probably because of
4010 -- an error in the structure of the tree due to an incorrect program. Or
4011 -- it may be a bug in the optimization circuit. In either case the safest
4012 -- thing is simply to set the check flag unconditionally.
4016 Activate_Range_Check (N);
4018 if Debug_Flag_CC then
4019 w (" exception occurred, range flag set");
4023 end Enable_Range_Check;
4029 procedure Ensure_Valid (Expr : Node_Id; Holes_OK : Boolean := False) is
4030 Typ : constant Entity_Id := Etype (Expr);
4033 -- Ignore call if we are not doing any validity checking
4035 if not Validity_Checks_On then
4038 -- Ignore call if range or validity checks suppressed on entity or type
4040 elsif Range_Or_Validity_Checks_Suppressed (Expr) then
4043 -- No check required if expression is from the expander, we assume the
4044 -- expander will generate whatever checks are needed. Note that this is
4045 -- not just an optimization, it avoids infinite recursions!
4047 -- Unchecked conversions must be checked, unless they are initialized
4048 -- scalar values, as in a component assignment in an init proc.
4050 -- In addition, we force a check if Force_Validity_Checks is set
4052 elsif not Comes_From_Source (Expr)
4053 and then not Force_Validity_Checks
4054 and then (Nkind (Expr) /= N_Unchecked_Type_Conversion
4055 or else Kill_Range_Check (Expr))
4059 -- No check required if expression is known to have valid value
4061 elsif Expr_Known_Valid (Expr) then
4064 -- Ignore case of enumeration with holes where the flag is set not to
4065 -- worry about holes, since no special validity check is needed
4067 elsif Is_Enumeration_Type (Typ)
4068 and then Has_Non_Standard_Rep (Typ)
4073 -- No check required on the left-hand side of an assignment
4075 elsif Nkind (Parent (Expr)) = N_Assignment_Statement
4076 and then Expr = Name (Parent (Expr))
4080 -- No check on a universal real constant. The context will eventually
4081 -- convert it to a machine number for some target type, or report an
4084 elsif Nkind (Expr) = N_Real_Literal
4085 and then Etype (Expr) = Universal_Real
4089 -- If the expression denotes a component of a packed boolean array,
4090 -- no possible check applies. We ignore the old ACATS chestnuts that
4091 -- involve Boolean range True..True.
4093 -- Note: validity checks are generated for expressions that yield a
4094 -- scalar type, when it is possible to create a value that is outside of
4095 -- the type. If this is a one-bit boolean no such value exists. This is
4096 -- an optimization, and it also prevents compiler blowing up during the
4097 -- elaboration of improperly expanded packed array references.
4099 elsif Nkind (Expr) = N_Indexed_Component
4100 and then Is_Bit_Packed_Array (Etype (Prefix (Expr)))
4101 and then Root_Type (Etype (Expr)) = Standard_Boolean
4105 -- An annoying special case. If this is an out parameter of a scalar
4106 -- type, then the value is not going to be accessed, therefore it is
4107 -- inappropriate to do any validity check at the call site.
4110 -- Only need to worry about scalar types
4112 if Is_Scalar_Type (Typ) then
4122 -- Find actual argument (which may be a parameter association)
4123 -- and the parent of the actual argument (the call statement)
4128 if Nkind (P) = N_Parameter_Association then
4133 -- Only need to worry if we are argument of a procedure call
4134 -- since functions don't have out parameters. If this is an
4135 -- indirect or dispatching call, get signature from the
4138 if Nkind (P) = N_Procedure_Call_Statement then
4139 L := Parameter_Associations (P);
4141 if Is_Entity_Name (Name (P)) then
4142 E := Entity (Name (P));
4144 pragma Assert (Nkind (Name (P)) = N_Explicit_Dereference);
4145 E := Etype (Name (P));
4148 -- Only need to worry if there are indeed actuals, and if
4149 -- this could be a procedure call, otherwise we cannot get a
4150 -- match (either we are not an argument, or the mode of the
4151 -- formal is not OUT). This test also filters out the
4154 if Is_Non_Empty_List (L)
4155 and then Is_Subprogram (E)
4157 -- This is the loop through parameters, looking for an
4158 -- OUT parameter for which we are the argument.
4160 F := First_Formal (E);
4162 while Present (F) loop
4163 if Ekind (F) = E_Out_Parameter and then A = N then
4176 -- If this is a boolean expression, only its elementary operands need
4177 -- checking: if they are valid, a boolean or short-circuit operation
4178 -- with them will be valid as well.
4180 if Base_Type (Typ) = Standard_Boolean
4182 (Nkind (Expr) in N_Op or else Nkind (Expr) in N_Short_Circuit)
4187 -- If we fall through, a validity check is required
4189 Insert_Valid_Check (Expr);
4191 if Is_Entity_Name (Expr)
4192 and then Safe_To_Capture_Value (Expr, Entity (Expr))
4194 Set_Is_Known_Valid (Entity (Expr));
4198 ----------------------
4199 -- Expr_Known_Valid --
4200 ----------------------
4202 function Expr_Known_Valid (Expr : Node_Id) return Boolean is
4203 Typ : constant Entity_Id := Etype (Expr);
4206 -- Non-scalar types are always considered valid, since they never give
4207 -- rise to the issues of erroneous or bounded error behavior that are
4208 -- the concern. In formal reference manual terms the notion of validity
4209 -- only applies to scalar types. Note that even when packed arrays are
4210 -- represented using modular types, they are still arrays semantically,
4211 -- so they are also always valid (in particular, the unused bits can be
4212 -- random rubbish without affecting the validity of the array value).
4214 if not Is_Scalar_Type (Typ) or else Is_Packed_Array_Type (Typ) then
4217 -- If no validity checking, then everything is considered valid
4219 elsif not Validity_Checks_On then
4222 -- Floating-point types are considered valid unless floating-point
4223 -- validity checks have been specifically turned on.
4225 elsif Is_Floating_Point_Type (Typ)
4226 and then not Validity_Check_Floating_Point
4230 -- If the expression is the value of an object that is known to be
4231 -- valid, then clearly the expression value itself is valid.
4233 elsif Is_Entity_Name (Expr)
4234 and then Is_Known_Valid (Entity (Expr))
4238 -- References to discriminants are always considered valid. The value
4239 -- of a discriminant gets checked when the object is built. Within the
4240 -- record, we consider it valid, and it is important to do so, since
4241 -- otherwise we can try to generate bogus validity checks which
4242 -- reference discriminants out of scope. Discriminants of concurrent
4243 -- types are excluded for the same reason.
4245 elsif Is_Entity_Name (Expr)
4246 and then Denotes_Discriminant (Expr, Check_Concurrent => True)
4250 -- If the type is one for which all values are known valid, then we are
4251 -- sure that the value is valid except in the slightly odd case where
4252 -- the expression is a reference to a variable whose size has been
4253 -- explicitly set to a value greater than the object size.
4255 elsif Is_Known_Valid (Typ) then
4256 if Is_Entity_Name (Expr)
4257 and then Ekind (Entity (Expr)) = E_Variable
4258 and then Esize (Entity (Expr)) > Esize (Typ)
4265 -- Integer and character literals always have valid values, where
4266 -- appropriate these will be range checked in any case.
4268 elsif Nkind (Expr) = N_Integer_Literal
4270 Nkind (Expr) = N_Character_Literal
4274 -- If we have a type conversion or a qualification of a known valid
4275 -- value, then the result will always be valid.
4277 elsif Nkind (Expr) = N_Type_Conversion
4279 Nkind (Expr) = N_Qualified_Expression
4281 return Expr_Known_Valid (Expression (Expr));
4283 -- The result of any operator is always considered valid, since we
4284 -- assume the necessary checks are done by the operator. For operators
4285 -- on floating-point operations, we must also check when the operation
4286 -- is the right-hand side of an assignment, or is an actual in a call.
4288 elsif Nkind (Expr) in N_Op then
4289 if Is_Floating_Point_Type (Typ)
4290 and then Validity_Check_Floating_Point
4292 (Nkind (Parent (Expr)) = N_Assignment_Statement
4293 or else Nkind (Parent (Expr)) = N_Function_Call
4294 or else Nkind (Parent (Expr)) = N_Parameter_Association)
4301 -- The result of a membership test is always valid, since it is true or
4302 -- false, there are no other possibilities.
4304 elsif Nkind (Expr) in N_Membership_Test then
4307 -- For all other cases, we do not know the expression is valid
4312 end Expr_Known_Valid;
4318 procedure Find_Check
4320 Check_Type : Character;
4321 Target_Type : Entity_Id;
4322 Entry_OK : out Boolean;
4323 Check_Num : out Nat;
4324 Ent : out Entity_Id;
4327 function Within_Range_Of
4328 (Target_Type : Entity_Id;
4329 Check_Type : Entity_Id) return Boolean;
4330 -- Given a requirement for checking a range against Target_Type, and
4331 -- and a range Check_Type against which a check has already been made,
4332 -- determines if the check against check type is sufficient to ensure
4333 -- that no check against Target_Type is required.
4335 ---------------------
4336 -- Within_Range_Of --
4337 ---------------------
4339 function Within_Range_Of
4340 (Target_Type : Entity_Id;
4341 Check_Type : Entity_Id) return Boolean
4344 if Target_Type = Check_Type then
4349 Tlo : constant Node_Id := Type_Low_Bound (Target_Type);
4350 Thi : constant Node_Id := Type_High_Bound (Target_Type);
4351 Clo : constant Node_Id := Type_Low_Bound (Check_Type);
4352 Chi : constant Node_Id := Type_High_Bound (Check_Type);
4356 or else (Compile_Time_Known_Value (Tlo)
4358 Compile_Time_Known_Value (Clo)
4360 Expr_Value (Clo) >= Expr_Value (Tlo)))
4363 or else (Compile_Time_Known_Value (Thi)
4365 Compile_Time_Known_Value (Chi)
4367 Expr_Value (Chi) <= Expr_Value (Clo)))
4375 end Within_Range_Of;
4377 -- Start of processing for Find_Check
4380 -- Establish default, in case no entry is found
4384 -- Case of expression is simple entity reference
4386 if Is_Entity_Name (Expr) then
4387 Ent := Entity (Expr);
4390 -- Case of expression is entity + known constant
4392 elsif Nkind (Expr) = N_Op_Add
4393 and then Compile_Time_Known_Value (Right_Opnd (Expr))
4394 and then Is_Entity_Name (Left_Opnd (Expr))
4396 Ent := Entity (Left_Opnd (Expr));
4397 Ofs := Expr_Value (Right_Opnd (Expr));
4399 -- Case of expression is entity - known constant
4401 elsif Nkind (Expr) = N_Op_Subtract
4402 and then Compile_Time_Known_Value (Right_Opnd (Expr))
4403 and then Is_Entity_Name (Left_Opnd (Expr))
4405 Ent := Entity (Left_Opnd (Expr));
4406 Ofs := UI_Negate (Expr_Value (Right_Opnd (Expr)));
4408 -- Any other expression is not of the right form
4417 -- Come here with expression of appropriate form, check if entity is an
4418 -- appropriate one for our purposes.
4420 if (Ekind (Ent) = E_Variable
4421 or else Is_Constant_Object (Ent))
4422 and then not Is_Library_Level_Entity (Ent)
4430 -- See if there is matching check already
4432 for J in reverse 1 .. Num_Saved_Checks loop
4434 SC : Saved_Check renames Saved_Checks (J);
4437 if SC.Killed = False
4438 and then SC.Entity = Ent
4439 and then SC.Offset = Ofs
4440 and then SC.Check_Type = Check_Type
4441 and then Within_Range_Of (Target_Type, SC.Target_Type)
4449 -- If we fall through entry was not found
4454 ---------------------------------
4455 -- Generate_Discriminant_Check --
4456 ---------------------------------
4458 -- Note: the code for this procedure is derived from the
4459 -- Emit_Discriminant_Check Routine in trans.c.
4461 procedure Generate_Discriminant_Check (N : Node_Id) is
4462 Loc : constant Source_Ptr := Sloc (N);
4463 Pref : constant Node_Id := Prefix (N);
4464 Sel : constant Node_Id := Selector_Name (N);
4466 Orig_Comp : constant Entity_Id :=
4467 Original_Record_Component (Entity (Sel));
4468 -- The original component to be checked
4470 Discr_Fct : constant Entity_Id :=
4471 Discriminant_Checking_Func (Orig_Comp);
4472 -- The discriminant checking function
4475 -- One discriminant to be checked in the type
4477 Real_Discr : Entity_Id;
4478 -- Actual discriminant in the call
4480 Pref_Type : Entity_Id;
4481 -- Type of relevant prefix (ignoring private/access stuff)
4484 -- List of arguments for function call
4487 -- Keep track of the formal corresponding to the actual we build for
4488 -- each discriminant, in order to be able to perform the necessary type
4492 -- Selected component reference for checking function argument
4495 Pref_Type := Etype (Pref);
4497 -- Force evaluation of the prefix, so that it does not get evaluated
4498 -- twice (once for the check, once for the actual reference). Such a
4499 -- double evaluation is always a potential source of inefficiency,
4500 -- and is functionally incorrect in the volatile case, or when the
4501 -- prefix may have side-effects. An entity or a component of an
4502 -- entity requires no evaluation.
4504 if Is_Entity_Name (Pref) then
4505 if Treat_As_Volatile (Entity (Pref)) then
4506 Force_Evaluation (Pref, Name_Req => True);
4509 elsif Treat_As_Volatile (Etype (Pref)) then
4510 Force_Evaluation (Pref, Name_Req => True);
4512 elsif Nkind (Pref) = N_Selected_Component
4513 and then Is_Entity_Name (Prefix (Pref))
4518 Force_Evaluation (Pref, Name_Req => True);
4521 -- For a tagged type, use the scope of the original component to
4522 -- obtain the type, because ???
4524 if Is_Tagged_Type (Scope (Orig_Comp)) then
4525 Pref_Type := Scope (Orig_Comp);
4527 -- For an untagged derived type, use the discriminants of the parent
4528 -- which have been renamed in the derivation, possibly by a one-to-many
4529 -- discriminant constraint. For non-tagged type, initially get the Etype
4533 if Is_Derived_Type (Pref_Type)
4534 and then Number_Discriminants (Pref_Type) /=
4535 Number_Discriminants (Etype (Base_Type (Pref_Type)))
4537 Pref_Type := Etype (Base_Type (Pref_Type));
4541 -- We definitely should have a checking function, This routine should
4542 -- not be called if no discriminant checking function is present.
4544 pragma Assert (Present (Discr_Fct));
4546 -- Create the list of the actual parameters for the call. This list
4547 -- is the list of the discriminant fields of the record expression to
4548 -- be discriminant checked.
4551 Formal := First_Formal (Discr_Fct);
4552 Discr := First_Discriminant (Pref_Type);
4553 while Present (Discr) loop
4555 -- If we have a corresponding discriminant field, and a parent
4556 -- subtype is present, then we want to use the corresponding
4557 -- discriminant since this is the one with the useful value.
4559 if Present (Corresponding_Discriminant (Discr))
4560 and then Ekind (Pref_Type) = E_Record_Type
4561 and then Present (Parent_Subtype (Pref_Type))
4563 Real_Discr := Corresponding_Discriminant (Discr);
4565 Real_Discr := Discr;
4568 -- Construct the reference to the discriminant
4571 Make_Selected_Component (Loc,
4573 Unchecked_Convert_To (Pref_Type,
4574 Duplicate_Subexpr (Pref)),
4575 Selector_Name => New_Occurrence_Of (Real_Discr, Loc));
4577 -- Manually analyze and resolve this selected component. We really
4578 -- want it just as it appears above, and do not want the expander
4579 -- playing discriminal games etc with this reference. Then we append
4580 -- the argument to the list we are gathering.
4582 Set_Etype (Scomp, Etype (Real_Discr));
4583 Set_Analyzed (Scomp, True);
4584 Append_To (Args, Convert_To (Etype (Formal), Scomp));
4586 Next_Formal_With_Extras (Formal);
4587 Next_Discriminant (Discr);
4590 -- Now build and insert the call
4593 Make_Raise_Constraint_Error (Loc,
4595 Make_Function_Call (Loc,
4596 Name => New_Occurrence_Of (Discr_Fct, Loc),
4597 Parameter_Associations => Args),
4598 Reason => CE_Discriminant_Check_Failed));
4599 end Generate_Discriminant_Check;
4601 ---------------------------
4602 -- Generate_Index_Checks --
4603 ---------------------------
4605 procedure Generate_Index_Checks (N : Node_Id) is
4607 function Entity_Of_Prefix return Entity_Id;
4608 -- Returns the entity of the prefix of N (or Empty if not found)
4610 ----------------------
4611 -- Entity_Of_Prefix --
4612 ----------------------
4614 function Entity_Of_Prefix return Entity_Id is
4619 while not Is_Entity_Name (P) loop
4620 if not Nkind_In (P, N_Selected_Component,
4621 N_Indexed_Component)
4630 end Entity_Of_Prefix;
4634 Loc : constant Source_Ptr := Sloc (N);
4635 A : constant Node_Id := Prefix (N);
4636 A_Ent : constant Entity_Id := Entity_Of_Prefix;
4639 -- Start of processing for Generate_Index_Checks
4642 -- Ignore call if the prefix is not an array since we have a serious
4643 -- error in the sources. Ignore it also if index checks are suppressed
4644 -- for array object or type.
4646 if not Is_Array_Type (Etype (A))
4647 or else (Present (A_Ent)
4648 and then Index_Checks_Suppressed (A_Ent))
4649 or else Index_Checks_Suppressed (Etype (A))
4654 -- Generate a raise of constraint error with the appropriate reason and
4655 -- a condition of the form:
4657 -- Base_Type (Sub) not in Array'Range (Subscript)
4659 -- Note that the reason we generate the conversion to the base type here
4660 -- is that we definitely want the range check to take place, even if it
4661 -- looks like the subtype is OK. Optimization considerations that allow
4662 -- us to omit the check have already been taken into account in the
4663 -- setting of the Do_Range_Check flag earlier on.
4665 Sub := First (Expressions (N));
4667 -- Handle string literals
4669 if Ekind (Etype (A)) = E_String_Literal_Subtype then
4670 if Do_Range_Check (Sub) then
4671 Set_Do_Range_Check (Sub, False);
4673 -- For string literals we obtain the bounds of the string from the
4674 -- associated subtype.
4677 Make_Raise_Constraint_Error (Loc,
4681 Convert_To (Base_Type (Etype (Sub)),
4682 Duplicate_Subexpr_Move_Checks (Sub)),
4684 Make_Attribute_Reference (Loc,
4685 Prefix => New_Reference_To (Etype (A), Loc),
4686 Attribute_Name => Name_Range)),
4687 Reason => CE_Index_Check_Failed));
4694 A_Idx : Node_Id := Empty;
4701 A_Idx := First_Index (Etype (A));
4703 while Present (Sub) loop
4704 if Do_Range_Check (Sub) then
4705 Set_Do_Range_Check (Sub, False);
4707 -- Force evaluation except for the case of a simple name of
4708 -- a non-volatile entity.
4710 if not Is_Entity_Name (Sub)
4711 or else Treat_As_Volatile (Entity (Sub))
4713 Force_Evaluation (Sub);
4716 if Nkind (A_Idx) = N_Range then
4719 elsif Nkind (A_Idx) = N_Identifier
4720 or else Nkind (A_Idx) = N_Expanded_Name
4722 A_Range := Scalar_Range (Entity (A_Idx));
4724 else pragma Assert (Nkind (A_Idx) = N_Subtype_Indication);
4725 A_Range := Range_Expression (Constraint (A_Idx));
4728 -- For array objects with constant bounds we can generate
4729 -- the index check using the bounds of the type of the index
4732 and then Ekind (A_Ent) = E_Variable
4733 and then Is_Constant_Bound (Low_Bound (A_Range))
4734 and then Is_Constant_Bound (High_Bound (A_Range))
4737 Make_Attribute_Reference (Loc,
4739 New_Reference_To (Etype (A_Idx), Loc),
4740 Attribute_Name => Name_Range);
4742 -- For arrays with non-constant bounds we cannot generate
4743 -- the index check using the bounds of the type of the index
4744 -- since it may reference discriminants of some enclosing
4745 -- type. We obtain the bounds directly from the prefix
4752 Num := New_List (Make_Integer_Literal (Loc, Ind));
4756 Make_Attribute_Reference (Loc,
4758 Duplicate_Subexpr_Move_Checks (A, Name_Req => True),
4759 Attribute_Name => Name_Range,
4760 Expressions => Num);
4764 Make_Raise_Constraint_Error (Loc,
4768 Convert_To (Base_Type (Etype (Sub)),
4769 Duplicate_Subexpr_Move_Checks (Sub)),
4770 Right_Opnd => Range_N),
4771 Reason => CE_Index_Check_Failed));
4774 A_Idx := Next_Index (A_Idx);
4780 end Generate_Index_Checks;
4782 --------------------------
4783 -- Generate_Range_Check --
4784 --------------------------
4786 procedure Generate_Range_Check
4788 Target_Type : Entity_Id;
4789 Reason : RT_Exception_Code)
4791 Loc : constant Source_Ptr := Sloc (N);
4792 Source_Type : constant Entity_Id := Etype (N);
4793 Source_Base_Type : constant Entity_Id := Base_Type (Source_Type);
4794 Target_Base_Type : constant Entity_Id := Base_Type (Target_Type);
4797 -- First special case, if the source type is already within the range
4798 -- of the target type, then no check is needed (probably we should have
4799 -- stopped Do_Range_Check from being set in the first place, but better
4800 -- late than later in preventing junk code!
4802 -- We do NOT apply this if the source node is a literal, since in this
4803 -- case the literal has already been labeled as having the subtype of
4806 if In_Subrange_Of (Source_Type, Target_Type)
4808 (Nkind (N) = N_Integer_Literal
4810 Nkind (N) = N_Real_Literal
4812 Nkind (N) = N_Character_Literal
4815 and then Ekind (Entity (N)) = E_Enumeration_Literal))
4820 -- We need a check, so force evaluation of the node, so that it does
4821 -- not get evaluated twice (once for the check, once for the actual
4822 -- reference). Such a double evaluation is always a potential source
4823 -- of inefficiency, and is functionally incorrect in the volatile case.
4825 if not Is_Entity_Name (N)
4826 or else Treat_As_Volatile (Entity (N))
4828 Force_Evaluation (N);
4831 -- The easiest case is when Source_Base_Type and Target_Base_Type are
4832 -- the same since in this case we can simply do a direct check of the
4833 -- value of N against the bounds of Target_Type.
4835 -- [constraint_error when N not in Target_Type]
4837 -- Note: this is by far the most common case, for example all cases of
4838 -- checks on the RHS of assignments are in this category, but not all
4839 -- cases are like this. Notably conversions can involve two types.
4841 if Source_Base_Type = Target_Base_Type then
4843 Make_Raise_Constraint_Error (Loc,
4846 Left_Opnd => Duplicate_Subexpr (N),
4847 Right_Opnd => New_Occurrence_Of (Target_Type, Loc)),
4850 -- Next test for the case where the target type is within the bounds
4851 -- of the base type of the source type, since in this case we can
4852 -- simply convert these bounds to the base type of T to do the test.
4854 -- [constraint_error when N not in
4855 -- Source_Base_Type (Target_Type'First)
4857 -- Source_Base_Type(Target_Type'Last))]
4859 -- The conversions will always work and need no check
4861 -- Unchecked_Convert_To is used instead of Convert_To to handle the case
4862 -- of converting from an enumeration value to an integer type, such as
4863 -- occurs for the case of generating a range check on Enum'Val(Exp)
4864 -- (which used to be handled by gigi). This is OK, since the conversion
4865 -- itself does not require a check.
4867 elsif In_Subrange_Of (Target_Type, Source_Base_Type) then
4869 Make_Raise_Constraint_Error (Loc,
4872 Left_Opnd => Duplicate_Subexpr (N),
4877 Unchecked_Convert_To (Source_Base_Type,
4878 Make_Attribute_Reference (Loc,
4880 New_Occurrence_Of (Target_Type, Loc),
4881 Attribute_Name => Name_First)),
4884 Unchecked_Convert_To (Source_Base_Type,
4885 Make_Attribute_Reference (Loc,
4887 New_Occurrence_Of (Target_Type, Loc),
4888 Attribute_Name => Name_Last)))),
4891 -- Note that at this stage we now that the Target_Base_Type is not in
4892 -- the range of the Source_Base_Type (since even the Target_Type itself
4893 -- is not in this range). It could still be the case that Source_Type is
4894 -- in range of the target base type since we have not checked that case.
4896 -- If that is the case, we can freely convert the source to the target,
4897 -- and then test the target result against the bounds.
4899 elsif In_Subrange_Of (Source_Type, Target_Base_Type) then
4901 -- We make a temporary to hold the value of the converted value
4902 -- (converted to the base type), and then we will do the test against
4905 -- Tnn : constant Target_Base_Type := Target_Base_Type (N);
4906 -- [constraint_error when Tnn not in Target_Type]
4908 -- Then the conversion itself is replaced by an occurrence of Tnn
4911 Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N);
4914 Insert_Actions (N, New_List (
4915 Make_Object_Declaration (Loc,
4916 Defining_Identifier => Tnn,
4917 Object_Definition =>
4918 New_Occurrence_Of (Target_Base_Type, Loc),
4919 Constant_Present => True,
4921 Make_Type_Conversion (Loc,
4922 Subtype_Mark => New_Occurrence_Of (Target_Base_Type, Loc),
4923 Expression => Duplicate_Subexpr (N))),
4925 Make_Raise_Constraint_Error (Loc,
4928 Left_Opnd => New_Occurrence_Of (Tnn, Loc),
4929 Right_Opnd => New_Occurrence_Of (Target_Type, Loc)),
4931 Reason => Reason)));
4933 Rewrite (N, New_Occurrence_Of (Tnn, Loc));
4935 -- Set the type of N, because the declaration for Tnn might not
4936 -- be analyzed yet, as is the case if N appears within a record
4937 -- declaration, as a discriminant constraint or expression.
4939 Set_Etype (N, Target_Base_Type);
4942 -- At this stage, we know that we have two scalar types, which are
4943 -- directly convertible, and where neither scalar type has a base
4944 -- range that is in the range of the other scalar type.
4946 -- The only way this can happen is with a signed and unsigned type.
4947 -- So test for these two cases:
4950 -- Case of the source is unsigned and the target is signed
4952 if Is_Unsigned_Type (Source_Base_Type)
4953 and then not Is_Unsigned_Type (Target_Base_Type)
4955 -- If the source is unsigned and the target is signed, then we
4956 -- know that the source is not shorter than the target (otherwise
4957 -- the source base type would be in the target base type range).
4959 -- In other words, the unsigned type is either the same size as
4960 -- the target, or it is larger. It cannot be smaller.
4963 (Esize (Source_Base_Type) >= Esize (Target_Base_Type));
4965 -- We only need to check the low bound if the low bound of the
4966 -- target type is non-negative. If the low bound of the target
4967 -- type is negative, then we know that we will fit fine.
4969 -- If the high bound of the target type is negative, then we
4970 -- know we have a constraint error, since we can't possibly
4971 -- have a negative source.
4973 -- With these two checks out of the way, we can do the check
4974 -- using the source type safely
4976 -- This is definitely the most annoying case!
4978 -- [constraint_error
4979 -- when (Target_Type'First >= 0
4981 -- N < Source_Base_Type (Target_Type'First))
4982 -- or else Target_Type'Last < 0
4983 -- or else N > Source_Base_Type (Target_Type'Last)];
4985 -- We turn off all checks since we know that the conversions
4986 -- will work fine, given the guards for negative values.
4989 Make_Raise_Constraint_Error (Loc,
4995 Left_Opnd => Make_Op_Ge (Loc,
4997 Make_Attribute_Reference (Loc,
4999 New_Occurrence_Of (Target_Type, Loc),
5000 Attribute_Name => Name_First),
5001 Right_Opnd => Make_Integer_Literal (Loc, Uint_0)),
5005 Left_Opnd => Duplicate_Subexpr (N),
5007 Convert_To (Source_Base_Type,
5008 Make_Attribute_Reference (Loc,
5010 New_Occurrence_Of (Target_Type, Loc),
5011 Attribute_Name => Name_First)))),
5016 Make_Attribute_Reference (Loc,
5017 Prefix => New_Occurrence_Of (Target_Type, Loc),
5018 Attribute_Name => Name_Last),
5019 Right_Opnd => Make_Integer_Literal (Loc, Uint_0))),
5023 Left_Opnd => Duplicate_Subexpr (N),
5025 Convert_To (Source_Base_Type,
5026 Make_Attribute_Reference (Loc,
5027 Prefix => New_Occurrence_Of (Target_Type, Loc),
5028 Attribute_Name => Name_Last)))),
5031 Suppress => All_Checks);
5033 -- Only remaining possibility is that the source is signed and
5034 -- the target is unsigned.
5037 pragma Assert (not Is_Unsigned_Type (Source_Base_Type)
5038 and then Is_Unsigned_Type (Target_Base_Type));
5040 -- If the source is signed and the target is unsigned, then we
5041 -- know that the target is not shorter than the source (otherwise
5042 -- the target base type would be in the source base type range).
5044 -- In other words, the unsigned type is either the same size as
5045 -- the target, or it is larger. It cannot be smaller.
5047 -- Clearly we have an error if the source value is negative since
5048 -- no unsigned type can have negative values. If the source type
5049 -- is non-negative, then the check can be done using the target
5052 -- Tnn : constant Target_Base_Type (N) := Target_Type;
5054 -- [constraint_error
5055 -- when N < 0 or else Tnn not in Target_Type];
5057 -- We turn off all checks for the conversion of N to the target
5058 -- base type, since we generate the explicit check to ensure that
5059 -- the value is non-negative
5062 Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N);
5065 Insert_Actions (N, New_List (
5066 Make_Object_Declaration (Loc,
5067 Defining_Identifier => Tnn,
5068 Object_Definition =>
5069 New_Occurrence_Of (Target_Base_Type, Loc),
5070 Constant_Present => True,
5072 Make_Unchecked_Type_Conversion (Loc,
5074 New_Occurrence_Of (Target_Base_Type, Loc),
5075 Expression => Duplicate_Subexpr (N))),
5077 Make_Raise_Constraint_Error (Loc,
5082 Left_Opnd => Duplicate_Subexpr (N),
5083 Right_Opnd => Make_Integer_Literal (Loc, Uint_0)),
5087 Left_Opnd => New_Occurrence_Of (Tnn, Loc),
5089 New_Occurrence_Of (Target_Type, Loc))),
5092 Suppress => All_Checks);
5094 -- Set the Etype explicitly, because Insert_Actions may have
5095 -- placed the declaration in the freeze list for an enclosing
5096 -- construct, and thus it is not analyzed yet.
5098 Set_Etype (Tnn, Target_Base_Type);
5099 Rewrite (N, New_Occurrence_Of (Tnn, Loc));
5103 end Generate_Range_Check;
5109 function Get_Check_Id (N : Name_Id) return Check_Id is
5111 -- For standard check name, we can do a direct computation
5113 if N in First_Check_Name .. Last_Check_Name then
5114 return Check_Id (N - (First_Check_Name - 1));
5116 -- For non-standard names added by pragma Check_Name, search table
5119 for J in All_Checks + 1 .. Check_Names.Last loop
5120 if Check_Names.Table (J) = N then
5126 -- No matching name found
5131 ---------------------
5132 -- Get_Discriminal --
5133 ---------------------
5135 function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is
5136 Loc : constant Source_Ptr := Sloc (E);
5141 -- The bound can be a bona fide parameter of a protected operation,
5142 -- rather than a prival encoded as an in-parameter.
5144 if No (Discriminal_Link (Entity (Bound))) then
5148 -- Climb the scope stack looking for an enclosing protected type. If
5149 -- we run out of scopes, return the bound itself.
5152 while Present (Sc) loop
5153 if Sc = Standard_Standard then
5156 elsif Ekind (Sc) = E_Protected_Type then
5163 D := First_Discriminant (Sc);
5164 while Present (D) loop
5165 if Chars (D) = Chars (Bound) then
5166 return New_Occurrence_Of (Discriminal (D), Loc);
5169 Next_Discriminant (D);
5173 end Get_Discriminal;
5175 ----------------------
5176 -- Get_Range_Checks --
5177 ----------------------
5179 function Get_Range_Checks
5181 Target_Typ : Entity_Id;
5182 Source_Typ : Entity_Id := Empty;
5183 Warn_Node : Node_Id := Empty) return Check_Result
5186 return Selected_Range_Checks
5187 (Ck_Node, Target_Typ, Source_Typ, Warn_Node);
5188 end Get_Range_Checks;
5194 function Guard_Access
5197 Ck_Node : Node_Id) return Node_Id
5200 if Nkind (Cond) = N_Or_Else then
5201 Set_Paren_Count (Cond, 1);
5204 if Nkind (Ck_Node) = N_Allocator then
5211 Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
5212 Right_Opnd => Make_Null (Loc)),
5213 Right_Opnd => Cond);
5217 -----------------------------
5218 -- Index_Checks_Suppressed --
5219 -----------------------------
5221 function Index_Checks_Suppressed (E : Entity_Id) return Boolean is
5223 if Present (E) and then Checks_May_Be_Suppressed (E) then
5224 return Is_Check_Suppressed (E, Index_Check);
5226 return Scope_Suppress (Index_Check);
5228 end Index_Checks_Suppressed;
5234 procedure Initialize is
5236 for J in Determine_Range_Cache_N'Range loop
5237 Determine_Range_Cache_N (J) := Empty;
5242 for J in Int range 1 .. All_Checks loop
5243 Check_Names.Append (Name_Id (Int (First_Check_Name) + J - 1));
5247 -------------------------
5248 -- Insert_Range_Checks --
5249 -------------------------
5251 procedure Insert_Range_Checks
5252 (Checks : Check_Result;
5254 Suppress_Typ : Entity_Id;
5255 Static_Sloc : Source_Ptr := No_Location;
5256 Flag_Node : Node_Id := Empty;
5257 Do_Before : Boolean := False)
5259 Internal_Flag_Node : Node_Id := Flag_Node;
5260 Internal_Static_Sloc : Source_Ptr := Static_Sloc;
5262 Check_Node : Node_Id;
5263 Checks_On : constant Boolean :=
5264 (not Index_Checks_Suppressed (Suppress_Typ))
5266 (not Range_Checks_Suppressed (Suppress_Typ));
5269 -- For now we just return if Checks_On is false, however this should be
5270 -- enhanced to check for an always True value in the condition and to
5271 -- generate a compilation warning???
5273 if not Expander_Active or else not Checks_On then
5277 if Static_Sloc = No_Location then
5278 Internal_Static_Sloc := Sloc (Node);
5281 if No (Flag_Node) then
5282 Internal_Flag_Node := Node;
5285 for J in 1 .. 2 loop
5286 exit when No (Checks (J));
5288 if Nkind (Checks (J)) = N_Raise_Constraint_Error
5289 and then Present (Condition (Checks (J)))
5291 if not Has_Dynamic_Range_Check (Internal_Flag_Node) then
5292 Check_Node := Checks (J);
5293 Mark_Rewrite_Insertion (Check_Node);
5296 Insert_Before_And_Analyze (Node, Check_Node);
5298 Insert_After_And_Analyze (Node, Check_Node);
5301 Set_Has_Dynamic_Range_Check (Internal_Flag_Node);
5306 Make_Raise_Constraint_Error (Internal_Static_Sloc,
5307 Reason => CE_Range_Check_Failed);
5308 Mark_Rewrite_Insertion (Check_Node);
5311 Insert_Before_And_Analyze (Node, Check_Node);
5313 Insert_After_And_Analyze (Node, Check_Node);
5317 end Insert_Range_Checks;
5319 ------------------------
5320 -- Insert_Valid_Check --
5321 ------------------------
5323 procedure Insert_Valid_Check (Expr : Node_Id) is
5324 Loc : constant Source_Ptr := Sloc (Expr);
5328 -- Do not insert if checks off, or if not checking validity or
5329 -- if expression is known to be valid
5331 if not Validity_Checks_On
5332 or else Range_Or_Validity_Checks_Suppressed (Expr)
5333 or else Expr_Known_Valid (Expr)
5338 -- If we have a checked conversion, then validity check applies to
5339 -- the expression inside the conversion, not the result, since if
5340 -- the expression inside is valid, then so is the conversion result.
5343 while Nkind (Exp) = N_Type_Conversion loop
5344 Exp := Expression (Exp);
5347 -- We are about to insert the validity check for Exp. We save and
5348 -- reset the Do_Range_Check flag over this validity check, and then
5349 -- put it back for the final original reference (Exp may be rewritten).
5352 DRC : constant Boolean := Do_Range_Check (Exp);
5355 Set_Do_Range_Check (Exp, False);
5357 -- Force evaluation to avoid multiple reads for atomic/volatile
5359 if Is_Entity_Name (Exp)
5360 and then Is_Volatile (Entity (Exp))
5362 Force_Evaluation (Exp, Name_Req => True);
5365 -- Insert the validity check. Note that we do this with validity
5366 -- checks turned off, to avoid recursion, we do not want validity
5367 -- checks on the validity checking code itself!
5371 Make_Raise_Constraint_Error (Loc,
5375 Make_Attribute_Reference (Loc,
5377 Duplicate_Subexpr_No_Checks (Exp, Name_Req => True),
5378 Attribute_Name => Name_Valid)),
5379 Reason => CE_Invalid_Data),
5380 Suppress => Validity_Check);
5382 -- If the expression is a reference to an element of a bit-packed
5383 -- array, then it is rewritten as a renaming declaration. If the
5384 -- expression is an actual in a call, it has not been expanded,
5385 -- waiting for the proper point at which to do it. The same happens
5386 -- with renamings, so that we have to force the expansion now. This
5387 -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb
5390 if Is_Entity_Name (Exp)
5391 and then Nkind (Parent (Entity (Exp))) =
5392 N_Object_Renaming_Declaration
5395 Old_Exp : constant Node_Id := Name (Parent (Entity (Exp)));
5397 if Nkind (Old_Exp) = N_Indexed_Component
5398 and then Is_Bit_Packed_Array (Etype (Prefix (Old_Exp)))
5400 Expand_Packed_Element_Reference (Old_Exp);
5405 -- Put back the Do_Range_Check flag on the resulting (possibly
5406 -- rewritten) expression.
5408 -- Note: it might be thought that a validity check is not required
5409 -- when a range check is present, but that's not the case, because
5410 -- the back end is allowed to assume for the range check that the
5411 -- operand is within its declared range (an assumption that validity
5412 -- checking is all about NOT assuming!)
5414 -- Note: no need to worry about Possible_Local_Raise here, it will
5415 -- already have been called if original node has Do_Range_Check set.
5417 Set_Do_Range_Check (Exp, DRC);
5419 end Insert_Valid_Check;
5421 ----------------------------------
5422 -- Install_Null_Excluding_Check --
5423 ----------------------------------
5425 procedure Install_Null_Excluding_Check (N : Node_Id) is
5426 Loc : constant Source_Ptr := Sloc (Parent (N));
5427 Typ : constant Entity_Id := Etype (N);
5429 function Safe_To_Capture_In_Parameter_Value return Boolean;
5430 -- Determines if it is safe to capture Known_Non_Null status for an
5431 -- the entity referenced by node N. The caller ensures that N is indeed
5432 -- an entity name. It is safe to capture the non-null status for an IN
5433 -- parameter when the reference occurs within a declaration that is sure
5434 -- to be executed as part of the declarative region.
5436 procedure Mark_Non_Null;
5437 -- After installation of check, if the node in question is an entity
5438 -- name, then mark this entity as non-null if possible.
5440 function Safe_To_Capture_In_Parameter_Value return Boolean is
5441 E : constant Entity_Id := Entity (N);
5442 S : constant Entity_Id := Current_Scope;
5446 if Ekind (E) /= E_In_Parameter then
5450 -- Two initial context checks. We must be inside a subprogram body
5451 -- with declarations and reference must not appear in nested scopes.
5453 if (Ekind (S) /= E_Function and then Ekind (S) /= E_Procedure)
5454 or else Scope (E) /= S
5459 S_Par := Parent (Parent (S));
5461 if Nkind (S_Par) /= N_Subprogram_Body
5462 or else No (Declarations (S_Par))
5472 -- Retrieve the declaration node of N (if any). Note that N
5473 -- may be a part of a complex initialization expression.
5477 while Present (P) loop
5479 -- If we have a short circuit form, and we are within the right
5480 -- hand expression, we return false, since the right hand side
5481 -- is not guaranteed to be elaborated.
5483 if Nkind (P) in N_Short_Circuit
5484 and then N = Right_Opnd (P)
5489 -- Similarly, if we are in a conditional expression and not
5490 -- part of the condition, then we return False, since neither
5491 -- the THEN or ELSE expressions will always be elaborated.
5493 if Nkind (P) = N_Conditional_Expression
5494 and then N /= First (Expressions (P))
5499 -- If we are in a case expression, and not part of the
5500 -- expression, then we return False, since a particular
5501 -- branch may not always be elaborated
5503 if Nkind (P) = N_Case_Expression
5504 and then N /= Expression (P)
5509 -- While traversing the parent chain, we find that N
5510 -- belongs to a statement, thus it may never appear in
5511 -- a declarative region.
5513 if Nkind (P) in N_Statement_Other_Than_Procedure_Call
5514 or else Nkind (P) = N_Procedure_Call_Statement
5519 -- If we are at a declaration, record it and exit
5521 if Nkind (P) in N_Declaration
5522 and then Nkind (P) not in N_Subprogram_Specification
5535 return List_Containing (N_Decl) = Declarations (S_Par);
5537 end Safe_To_Capture_In_Parameter_Value;
5543 procedure Mark_Non_Null is
5545 -- Only case of interest is if node N is an entity name
5547 if Is_Entity_Name (N) then
5549 -- For sure, we want to clear an indication that this is known to
5550 -- be null, since if we get past this check, it definitely is not!
5552 Set_Is_Known_Null (Entity (N), False);
5554 -- We can mark the entity as known to be non-null if either it is
5555 -- safe to capture the value, or in the case of an IN parameter,
5556 -- which is a constant, if the check we just installed is in the
5557 -- declarative region of the subprogram body. In this latter case,
5558 -- a check is decisive for the rest of the body if the expression
5559 -- is sure to be elaborated, since we know we have to elaborate
5560 -- all declarations before executing the body.
5562 -- Couldn't this always be part of Safe_To_Capture_Value ???
5564 if Safe_To_Capture_Value (N, Entity (N))
5565 or else Safe_To_Capture_In_Parameter_Value
5567 Set_Is_Known_Non_Null (Entity (N));
5572 -- Start of processing for Install_Null_Excluding_Check
5575 pragma Assert (Is_Access_Type (Typ));
5577 -- No check inside a generic (why not???)
5579 if Inside_A_Generic then
5583 -- No check needed if known to be non-null
5585 if Known_Non_Null (N) then
5589 -- If known to be null, here is where we generate a compile time check
5591 if Known_Null (N) then
5593 -- Avoid generating warning message inside init procs
5595 if not Inside_Init_Proc then
5596 Apply_Compile_Time_Constraint_Error
5598 "null value not allowed here?",
5599 CE_Access_Check_Failed);
5602 Make_Raise_Constraint_Error (Loc,
5603 Reason => CE_Access_Check_Failed));
5610 -- If entity is never assigned, for sure a warning is appropriate
5612 if Is_Entity_Name (N) then
5613 Check_Unset_Reference (N);
5616 -- No check needed if checks are suppressed on the range. Note that we
5617 -- don't set Is_Known_Non_Null in this case (we could legitimately do
5618 -- so, since the program is erroneous, but we don't like to casually
5619 -- propagate such conclusions from erroneosity).
5621 if Access_Checks_Suppressed (Typ) then
5625 -- No check needed for access to concurrent record types generated by
5626 -- the expander. This is not just an optimization (though it does indeed
5627 -- remove junk checks). It also avoids generation of junk warnings.
5629 if Nkind (N) in N_Has_Chars
5630 and then Chars (N) = Name_uObject
5631 and then Is_Concurrent_Record_Type
5632 (Directly_Designated_Type (Etype (N)))
5637 -- Otherwise install access check
5640 Make_Raise_Constraint_Error (Loc,
5643 Left_Opnd => Duplicate_Subexpr_Move_Checks (N),
5644 Right_Opnd => Make_Null (Loc)),
5645 Reason => CE_Access_Check_Failed));
5648 end Install_Null_Excluding_Check;
5650 --------------------------
5651 -- Install_Static_Check --
5652 --------------------------
5654 procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is
5655 Stat : constant Boolean := Is_Static_Expression (R_Cno);
5656 Typ : constant Entity_Id := Etype (R_Cno);
5660 Make_Raise_Constraint_Error (Loc,
5661 Reason => CE_Range_Check_Failed));
5662 Set_Analyzed (R_Cno);
5663 Set_Etype (R_Cno, Typ);
5664 Set_Raises_Constraint_Error (R_Cno);
5665 Set_Is_Static_Expression (R_Cno, Stat);
5667 -- Now deal with possible local raise handling
5669 Possible_Local_Raise (R_Cno, Standard_Constraint_Error);
5670 end Install_Static_Check;
5672 ---------------------
5673 -- Kill_All_Checks --
5674 ---------------------
5676 procedure Kill_All_Checks is
5678 if Debug_Flag_CC then
5679 w ("Kill_All_Checks");
5682 -- We reset the number of saved checks to zero, and also modify all
5683 -- stack entries for statement ranges to indicate that the number of
5684 -- checks at each level is now zero.
5686 Num_Saved_Checks := 0;
5688 -- Note: the Int'Min here avoids any possibility of J being out of
5689 -- range when called from e.g. Conditional_Statements_Begin.
5691 for J in 1 .. Int'Min (Saved_Checks_TOS, Saved_Checks_Stack'Last) loop
5692 Saved_Checks_Stack (J) := 0;
5694 end Kill_All_Checks;
5700 procedure Kill_Checks (V : Entity_Id) is
5702 if Debug_Flag_CC then
5703 w ("Kill_Checks for entity", Int (V));
5706 for J in 1 .. Num_Saved_Checks loop
5707 if Saved_Checks (J).Entity = V then
5708 if Debug_Flag_CC then
5709 w (" Checks killed for saved check ", J);
5712 Saved_Checks (J).Killed := True;
5717 ------------------------------
5718 -- Length_Checks_Suppressed --
5719 ------------------------------
5721 function Length_Checks_Suppressed (E : Entity_Id) return Boolean is
5723 if Present (E) and then Checks_May_Be_Suppressed (E) then
5724 return Is_Check_Suppressed (E, Length_Check);
5726 return Scope_Suppress (Length_Check);
5728 end Length_Checks_Suppressed;
5730 --------------------------------
5731 -- Overflow_Checks_Suppressed --
5732 --------------------------------
5734 function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is
5736 if Present (E) and then Checks_May_Be_Suppressed (E) then
5737 return Is_Check_Suppressed (E, Overflow_Check);
5739 return Scope_Suppress (Overflow_Check);
5741 end Overflow_Checks_Suppressed;
5743 -----------------------------
5744 -- Range_Checks_Suppressed --
5745 -----------------------------
5747 function Range_Checks_Suppressed (E : Entity_Id) return Boolean is
5751 -- Note: for now we always suppress range checks on Vax float types,
5752 -- since Gigi does not know how to generate these checks.
5754 if Vax_Float (E) then
5756 elsif Kill_Range_Checks (E) then
5758 elsif Checks_May_Be_Suppressed (E) then
5759 return Is_Check_Suppressed (E, Range_Check);
5763 return Scope_Suppress (Range_Check);
5764 end Range_Checks_Suppressed;
5766 -----------------------------------------
5767 -- Range_Or_Validity_Checks_Suppressed --
5768 -----------------------------------------
5770 -- Note: the coding would be simpler here if we simply made appropriate
5771 -- calls to Range/Validity_Checks_Suppressed, but that would result in
5772 -- duplicated checks which we prefer to avoid.
5774 function Range_Or_Validity_Checks_Suppressed
5775 (Expr : Node_Id) return Boolean
5778 -- Immediate return if scope checks suppressed for either check
5780 if Scope_Suppress (Range_Check) or Scope_Suppress (Validity_Check) then
5784 -- If no expression, that's odd, decide that checks are suppressed,
5785 -- since we don't want anyone trying to do checks in this case, which
5786 -- is most likely the result of some other error.
5792 -- Expression is present, so perform suppress checks on type
5795 Typ : constant Entity_Id := Etype (Expr);
5797 if Vax_Float (Typ) then
5799 elsif Checks_May_Be_Suppressed (Typ)
5800 and then (Is_Check_Suppressed (Typ, Range_Check)
5802 Is_Check_Suppressed (Typ, Validity_Check))
5808 -- If expression is an entity name, perform checks on this entity
5810 if Is_Entity_Name (Expr) then
5812 Ent : constant Entity_Id := Entity (Expr);
5814 if Checks_May_Be_Suppressed (Ent) then
5815 return Is_Check_Suppressed (Ent, Range_Check)
5816 or else Is_Check_Suppressed (Ent, Validity_Check);
5821 -- If we fall through, no checks suppressed
5824 end Range_Or_Validity_Checks_Suppressed;
5830 procedure Remove_Checks (Expr : Node_Id) is
5831 function Process (N : Node_Id) return Traverse_Result;
5832 -- Process a single node during the traversal
5834 procedure Traverse is new Traverse_Proc (Process);
5835 -- The traversal procedure itself
5841 function Process (N : Node_Id) return Traverse_Result is
5843 if Nkind (N) not in N_Subexpr then
5847 Set_Do_Range_Check (N, False);
5851 Traverse (Left_Opnd (N));
5854 when N_Attribute_Reference =>
5855 Set_Do_Overflow_Check (N, False);
5857 when N_Function_Call =>
5858 Set_Do_Tag_Check (N, False);
5861 Set_Do_Overflow_Check (N, False);
5865 Set_Do_Division_Check (N, False);
5868 Set_Do_Length_Check (N, False);
5871 Set_Do_Division_Check (N, False);
5874 Set_Do_Length_Check (N, False);
5877 Set_Do_Division_Check (N, False);
5880 Set_Do_Length_Check (N, False);
5887 Traverse (Left_Opnd (N));
5890 when N_Selected_Component =>
5891 Set_Do_Discriminant_Check (N, False);
5893 when N_Type_Conversion =>
5894 Set_Do_Length_Check (N, False);
5895 Set_Do_Tag_Check (N, False);
5896 Set_Do_Overflow_Check (N, False);
5905 -- Start of processing for Remove_Checks
5911 ----------------------------
5912 -- Selected_Length_Checks --
5913 ----------------------------
5915 function Selected_Length_Checks
5917 Target_Typ : Entity_Id;
5918 Source_Typ : Entity_Id;
5919 Warn_Node : Node_Id) return Check_Result
5921 Loc : constant Source_Ptr := Sloc (Ck_Node);
5924 Expr_Actual : Node_Id;
5926 Cond : Node_Id := Empty;
5927 Do_Access : Boolean := False;
5928 Wnode : Node_Id := Warn_Node;
5929 Ret_Result : Check_Result := (Empty, Empty);
5930 Num_Checks : Natural := 0;
5932 procedure Add_Check (N : Node_Id);
5933 -- Adds the action given to Ret_Result if N is non-Empty
5935 function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id;
5936 function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id;
5937 -- Comments required ???
5939 function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean;
5940 -- True for equal literals and for nodes that denote the same constant
5941 -- entity, even if its value is not a static constant. This includes the
5942 -- case of a discriminal reference within an init proc. Removes some
5943 -- obviously superfluous checks.
5945 function Length_E_Cond
5946 (Exptyp : Entity_Id;
5948 Indx : Nat) return Node_Id;
5949 -- Returns expression to compute:
5950 -- Typ'Length /= Exptyp'Length
5952 function Length_N_Cond
5955 Indx : Nat) return Node_Id;
5956 -- Returns expression to compute:
5957 -- Typ'Length /= Expr'Length
5963 procedure Add_Check (N : Node_Id) is
5967 -- For now, ignore attempt to place more than 2 checks ???
5969 if Num_Checks = 2 then
5973 pragma Assert (Num_Checks <= 1);
5974 Num_Checks := Num_Checks + 1;
5975 Ret_Result (Num_Checks) := N;
5983 function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is
5984 SE : constant Entity_Id := Scope (E);
5986 E1 : Entity_Id := E;
5989 if Ekind (Scope (E)) = E_Record_Type
5990 and then Has_Discriminants (Scope (E))
5992 N := Build_Discriminal_Subtype_Of_Component (E);
5995 Insert_Action (Ck_Node, N);
5996 E1 := Defining_Identifier (N);
6000 if Ekind (E1) = E_String_Literal_Subtype then
6002 Make_Integer_Literal (Loc,
6003 Intval => String_Literal_Length (E1));
6005 elsif SE /= Standard_Standard
6006 and then Ekind (Scope (SE)) = E_Protected_Type
6007 and then Has_Discriminants (Scope (SE))
6008 and then Has_Completion (Scope (SE))
6009 and then not Inside_Init_Proc
6011 -- If the type whose length is needed is a private component
6012 -- constrained by a discriminant, we must expand the 'Length
6013 -- attribute into an explicit computation, using the discriminal
6014 -- of the current protected operation. This is because the actual
6015 -- type of the prival is constructed after the protected opera-
6016 -- tion has been fully expanded.
6019 Indx_Type : Node_Id;
6022 Do_Expand : Boolean := False;
6025 Indx_Type := First_Index (E);
6027 for J in 1 .. Indx - 1 loop
6028 Next_Index (Indx_Type);
6031 Get_Index_Bounds (Indx_Type, Lo, Hi);
6033 if Nkind (Lo) = N_Identifier
6034 and then Ekind (Entity (Lo)) = E_In_Parameter
6036 Lo := Get_Discriminal (E, Lo);
6040 if Nkind (Hi) = N_Identifier
6041 and then Ekind (Entity (Hi)) = E_In_Parameter
6043 Hi := Get_Discriminal (E, Hi);
6048 if not Is_Entity_Name (Lo) then
6049 Lo := Duplicate_Subexpr_No_Checks (Lo);
6052 if not Is_Entity_Name (Hi) then
6053 Lo := Duplicate_Subexpr_No_Checks (Hi);
6059 Make_Op_Subtract (Loc,
6063 Right_Opnd => Make_Integer_Literal (Loc, 1));
6068 Make_Attribute_Reference (Loc,
6069 Attribute_Name => Name_Length,
6071 New_Occurrence_Of (E1, Loc));
6074 Set_Expressions (N, New_List (
6075 Make_Integer_Literal (Loc, Indx)));
6084 Make_Attribute_Reference (Loc,
6085 Attribute_Name => Name_Length,
6087 New_Occurrence_Of (E1, Loc));
6090 Set_Expressions (N, New_List (
6091 Make_Integer_Literal (Loc, Indx)));
6102 function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is
6105 Make_Attribute_Reference (Loc,
6106 Attribute_Name => Name_Length,
6108 Duplicate_Subexpr_No_Checks (N, Name_Req => True),
6109 Expressions => New_List (
6110 Make_Integer_Literal (Loc, Indx)));
6117 function Length_E_Cond
6118 (Exptyp : Entity_Id;
6120 Indx : Nat) return Node_Id
6125 Left_Opnd => Get_E_Length (Typ, Indx),
6126 Right_Opnd => Get_E_Length (Exptyp, Indx));
6133 function Length_N_Cond
6136 Indx : Nat) return Node_Id
6141 Left_Opnd => Get_E_Length (Typ, Indx),
6142 Right_Opnd => Get_N_Length (Expr, Indx));
6149 function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is
6152 (Nkind (L) = N_Integer_Literal
6153 and then Nkind (R) = N_Integer_Literal
6154 and then Intval (L) = Intval (R))
6158 and then Ekind (Entity (L)) = E_Constant
6159 and then ((Is_Entity_Name (R)
6160 and then Entity (L) = Entity (R))
6162 (Nkind (R) = N_Type_Conversion
6163 and then Is_Entity_Name (Expression (R))
6164 and then Entity (L) = Entity (Expression (R)))))
6168 and then Ekind (Entity (R)) = E_Constant
6169 and then Nkind (L) = N_Type_Conversion
6170 and then Is_Entity_Name (Expression (L))
6171 and then Entity (R) = Entity (Expression (L)))
6175 and then Is_Entity_Name (R)
6176 and then Entity (L) = Entity (R)
6177 and then Ekind (Entity (L)) = E_In_Parameter
6178 and then Inside_Init_Proc);
6181 -- Start of processing for Selected_Length_Checks
6184 if not Expander_Active then
6188 if Target_Typ = Any_Type
6189 or else Target_Typ = Any_Composite
6190 or else Raises_Constraint_Error (Ck_Node)
6199 T_Typ := Target_Typ;
6201 if No (Source_Typ) then
6202 S_Typ := Etype (Ck_Node);
6204 S_Typ := Source_Typ;
6207 if S_Typ = Any_Type or else S_Typ = Any_Composite then
6211 if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then
6212 S_Typ := Designated_Type (S_Typ);
6213 T_Typ := Designated_Type (T_Typ);
6216 -- A simple optimization for the null case
6218 if Known_Null (Ck_Node) then
6223 if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then
6224 if Is_Constrained (T_Typ) then
6226 -- The checking code to be generated will freeze the
6227 -- corresponding array type. However, we must freeze the
6228 -- type now, so that the freeze node does not appear within
6229 -- the generated conditional expression, but ahead of it.
6231 Freeze_Before (Ck_Node, T_Typ);
6233 Expr_Actual := Get_Referenced_Object (Ck_Node);
6234 Exptyp := Get_Actual_Subtype (Ck_Node);
6236 if Is_Access_Type (Exptyp) then
6237 Exptyp := Designated_Type (Exptyp);
6240 -- String_Literal case. This needs to be handled specially be-
6241 -- cause no index types are available for string literals. The
6242 -- condition is simply:
6244 -- T_Typ'Length = string-literal-length
6246 if Nkind (Expr_Actual) = N_String_Literal
6247 and then Ekind (Etype (Expr_Actual)) = E_String_Literal_Subtype
6251 Left_Opnd => Get_E_Length (T_Typ, 1),
6253 Make_Integer_Literal (Loc,
6255 String_Literal_Length (Etype (Expr_Actual))));
6257 -- General array case. Here we have a usable actual subtype for
6258 -- the expression, and the condition is built from the two types
6261 -- T_Typ'Length /= Exptyp'Length or else
6262 -- T_Typ'Length (2) /= Exptyp'Length (2) or else
6263 -- T_Typ'Length (3) /= Exptyp'Length (3) or else
6266 elsif Is_Constrained (Exptyp) then
6268 Ndims : constant Nat := Number_Dimensions (T_Typ);
6281 -- At the library level, we need to ensure that the type of
6282 -- the object is elaborated before the check itself is
6283 -- emitted. This is only done if the object is in the
6284 -- current compilation unit, otherwise the type is frozen
6285 -- and elaborated in its unit.
6287 if Is_Itype (Exptyp)
6289 Ekind (Cunit_Entity (Current_Sem_Unit)) = E_Package
6291 not In_Package_Body (Cunit_Entity (Current_Sem_Unit))
6292 and then In_Open_Scopes (Scope (Exptyp))
6294 Ref_Node := Make_Itype_Reference (Sloc (Ck_Node));
6295 Set_Itype (Ref_Node, Exptyp);
6296 Insert_Action (Ck_Node, Ref_Node);
6299 L_Index := First_Index (T_Typ);
6300 R_Index := First_Index (Exptyp);
6302 for Indx in 1 .. Ndims loop
6303 if not (Nkind (L_Index) = N_Raise_Constraint_Error
6305 Nkind (R_Index) = N_Raise_Constraint_Error)
6307 Get_Index_Bounds (L_Index, L_Low, L_High);
6308 Get_Index_Bounds (R_Index, R_Low, R_High);
6310 -- Deal with compile time length check. Note that we
6311 -- skip this in the access case, because the access
6312 -- value may be null, so we cannot know statically.
6315 and then Compile_Time_Known_Value (L_Low)
6316 and then Compile_Time_Known_Value (L_High)
6317 and then Compile_Time_Known_Value (R_Low)
6318 and then Compile_Time_Known_Value (R_High)
6320 if Expr_Value (L_High) >= Expr_Value (L_Low) then
6321 L_Length := Expr_Value (L_High) -
6322 Expr_Value (L_Low) + 1;
6324 L_Length := UI_From_Int (0);
6327 if Expr_Value (R_High) >= Expr_Value (R_Low) then
6328 R_Length := Expr_Value (R_High) -
6329 Expr_Value (R_Low) + 1;
6331 R_Length := UI_From_Int (0);
6334 if L_Length > R_Length then
6336 (Compile_Time_Constraint_Error
6337 (Wnode, "too few elements for}?", T_Typ));
6339 elsif L_Length < R_Length then
6341 (Compile_Time_Constraint_Error
6342 (Wnode, "too many elements for}?", T_Typ));
6345 -- The comparison for an individual index subtype
6346 -- is omitted if the corresponding index subtypes
6347 -- statically match, since the result is known to
6348 -- be true. Note that this test is worth while even
6349 -- though we do static evaluation, because non-static
6350 -- subtypes can statically match.
6353 Subtypes_Statically_Match
6354 (Etype (L_Index), Etype (R_Index))
6357 (Same_Bounds (L_Low, R_Low)
6358 and then Same_Bounds (L_High, R_High))
6361 (Cond, Length_E_Cond (Exptyp, T_Typ, Indx));
6370 -- Handle cases where we do not get a usable actual subtype that
6371 -- is constrained. This happens for example in the function call
6372 -- and explicit dereference cases. In these cases, we have to get
6373 -- the length or range from the expression itself, making sure we
6374 -- do not evaluate it more than once.
6376 -- Here Ck_Node is the original expression, or more properly the
6377 -- result of applying Duplicate_Expr to the original tree, forcing
6378 -- the result to be a name.
6382 Ndims : constant Nat := Number_Dimensions (T_Typ);
6385 -- Build the condition for the explicit dereference case
6387 for Indx in 1 .. Ndims loop
6389 (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx));
6396 -- Construct the test and insert into the tree
6398 if Present (Cond) then
6400 Cond := Guard_Access (Cond, Loc, Ck_Node);
6404 (Make_Raise_Constraint_Error (Loc,
6406 Reason => CE_Length_Check_Failed));
6410 end Selected_Length_Checks;
6412 ---------------------------
6413 -- Selected_Range_Checks --
6414 ---------------------------
6416 function Selected_Range_Checks
6418 Target_Typ : Entity_Id;
6419 Source_Typ : Entity_Id;
6420 Warn_Node : Node_Id) return Check_Result
6422 Loc : constant Source_Ptr := Sloc (Ck_Node);
6425 Expr_Actual : Node_Id;
6427 Cond : Node_Id := Empty;
6428 Do_Access : Boolean := False;
6429 Wnode : Node_Id := Warn_Node;
6430 Ret_Result : Check_Result := (Empty, Empty);
6431 Num_Checks : Integer := 0;
6433 procedure Add_Check (N : Node_Id);
6434 -- Adds the action given to Ret_Result if N is non-Empty
6436 function Discrete_Range_Cond
6438 Typ : Entity_Id) return Node_Id;
6439 -- Returns expression to compute:
6440 -- Low_Bound (Expr) < Typ'First
6442 -- High_Bound (Expr) > Typ'Last
6444 function Discrete_Expr_Cond
6446 Typ : Entity_Id) return Node_Id;
6447 -- Returns expression to compute:
6452 function Get_E_First_Or_Last
6456 Nam : Name_Id) return Node_Id;
6457 -- Returns an attribute reference
6458 -- E'First or E'Last
6459 -- with a source location of Loc.
6461 -- Nam is Name_First or Name_Last, according to which attribute is
6462 -- desired. If Indx is non-zero, it is passed as a literal in the
6463 -- Expressions of the attribute reference (identifying the desired
6464 -- array dimension).
6466 function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id;
6467 function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id;
6468 -- Returns expression to compute:
6469 -- N'First or N'Last using Duplicate_Subexpr_No_Checks
6471 function Range_E_Cond
6472 (Exptyp : Entity_Id;
6476 -- Returns expression to compute:
6477 -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
6479 function Range_Equal_E_Cond
6480 (Exptyp : Entity_Id;
6482 Indx : Nat) return Node_Id;
6483 -- Returns expression to compute:
6484 -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
6486 function Range_N_Cond
6489 Indx : Nat) return Node_Id;
6490 -- Return expression to compute:
6491 -- Expr'First < Typ'First or else Expr'Last > Typ'Last
6497 procedure Add_Check (N : Node_Id) is
6501 -- For now, ignore attempt to place more than 2 checks ???
6503 if Num_Checks = 2 then
6507 pragma Assert (Num_Checks <= 1);
6508 Num_Checks := Num_Checks + 1;
6509 Ret_Result (Num_Checks) := N;
6513 -------------------------
6514 -- Discrete_Expr_Cond --
6515 -------------------------
6517 function Discrete_Expr_Cond
6519 Typ : Entity_Id) return Node_Id
6527 Convert_To (Base_Type (Typ),
6528 Duplicate_Subexpr_No_Checks (Expr)),
6530 Convert_To (Base_Type (Typ),
6531 Get_E_First_Or_Last (Loc, Typ, 0, Name_First))),
6536 Convert_To (Base_Type (Typ),
6537 Duplicate_Subexpr_No_Checks (Expr)),
6541 Get_E_First_Or_Last (Loc, Typ, 0, Name_Last))));
6542 end Discrete_Expr_Cond;
6544 -------------------------
6545 -- Discrete_Range_Cond --
6546 -------------------------
6548 function Discrete_Range_Cond
6550 Typ : Entity_Id) return Node_Id
6552 LB : Node_Id := Low_Bound (Expr);
6553 HB : Node_Id := High_Bound (Expr);
6555 Left_Opnd : Node_Id;
6556 Right_Opnd : Node_Id;
6559 if Nkind (LB) = N_Identifier
6560 and then Ekind (Entity (LB)) = E_Discriminant
6562 LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc);
6565 if Nkind (HB) = N_Identifier
6566 and then Ekind (Entity (HB)) = E_Discriminant
6568 HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc);
6575 (Base_Type (Typ), Duplicate_Subexpr_No_Checks (LB)),
6580 Get_E_First_Or_Last (Loc, Typ, 0, Name_First)));
6582 if Base_Type (Typ) = Typ then
6585 elsif Compile_Time_Known_Value (High_Bound (Scalar_Range (Typ)))
6587 Compile_Time_Known_Value (High_Bound (Scalar_Range
6590 if Is_Floating_Point_Type (Typ) then
6591 if Expr_Value_R (High_Bound (Scalar_Range (Typ))) =
6592 Expr_Value_R (High_Bound (Scalar_Range (Base_Type (Typ))))
6598 if Expr_Value (High_Bound (Scalar_Range (Typ))) =
6599 Expr_Value (High_Bound (Scalar_Range (Base_Type (Typ))))
6610 (Base_Type (Typ), Duplicate_Subexpr_No_Checks (HB)),
6615 Get_E_First_Or_Last (Loc, Typ, 0, Name_Last)));
6617 return Make_Or_Else (Loc, Left_Opnd, Right_Opnd);
6618 end Discrete_Range_Cond;
6620 -------------------------
6621 -- Get_E_First_Or_Last --
6622 -------------------------
6624 function Get_E_First_Or_Last
6628 Nam : Name_Id) return Node_Id
6633 Exprs := New_List (Make_Integer_Literal (Loc, UI_From_Int (Indx)));
6638 return Make_Attribute_Reference (Loc,
6639 Prefix => New_Occurrence_Of (E, Loc),
6640 Attribute_Name => Nam,
6641 Expressions => Exprs);
6642 end Get_E_First_Or_Last;
6648 function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is
6651 Make_Attribute_Reference (Loc,
6652 Attribute_Name => Name_First,
6654 Duplicate_Subexpr_No_Checks (N, Name_Req => True),
6655 Expressions => New_List (
6656 Make_Integer_Literal (Loc, Indx)));
6663 function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is
6666 Make_Attribute_Reference (Loc,
6667 Attribute_Name => Name_Last,
6669 Duplicate_Subexpr_No_Checks (N, Name_Req => True),
6670 Expressions => New_List (
6671 Make_Integer_Literal (Loc, Indx)));
6678 function Range_E_Cond
6679 (Exptyp : Entity_Id;
6681 Indx : Nat) return Node_Id
6689 Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First),
6691 Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)),
6696 Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last),
6698 Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last)));
6701 ------------------------
6702 -- Range_Equal_E_Cond --
6703 ------------------------
6705 function Range_Equal_E_Cond
6706 (Exptyp : Entity_Id;
6708 Indx : Nat) return Node_Id
6716 Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First),
6718 Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)),
6723 Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last),
6725 Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last)));
6726 end Range_Equal_E_Cond;
6732 function Range_N_Cond
6735 Indx : Nat) return Node_Id
6743 Get_N_First (Expr, Indx),
6745 Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)),
6750 Get_N_Last (Expr, Indx),
6752 Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last)));
6755 -- Start of processing for Selected_Range_Checks
6758 if not Expander_Active then
6762 if Target_Typ = Any_Type
6763 or else Target_Typ = Any_Composite
6764 or else Raises_Constraint_Error (Ck_Node)
6773 T_Typ := Target_Typ;
6775 if No (Source_Typ) then
6776 S_Typ := Etype (Ck_Node);
6778 S_Typ := Source_Typ;
6781 if S_Typ = Any_Type or else S_Typ = Any_Composite then
6785 -- The order of evaluating T_Typ before S_Typ seems to be critical
6786 -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
6787 -- in, and since Node can be an N_Range node, it might be invalid.
6788 -- Should there be an assert check somewhere for taking the Etype of
6789 -- an N_Range node ???
6791 if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then
6792 S_Typ := Designated_Type (S_Typ);
6793 T_Typ := Designated_Type (T_Typ);
6796 -- A simple optimization for the null case
6798 if Known_Null (Ck_Node) then
6803 -- For an N_Range Node, check for a null range and then if not
6804 -- null generate a range check action.
6806 if Nkind (Ck_Node) = N_Range then
6808 -- There's no point in checking a range against itself
6810 if Ck_Node = Scalar_Range (T_Typ) then
6815 T_LB : constant Node_Id := Type_Low_Bound (T_Typ);
6816 T_HB : constant Node_Id := Type_High_Bound (T_Typ);
6817 Known_T_LB : constant Boolean := Compile_Time_Known_Value (T_LB);
6818 Known_T_HB : constant Boolean := Compile_Time_Known_Value (T_HB);
6820 LB : Node_Id := Low_Bound (Ck_Node);
6821 HB : Node_Id := High_Bound (Ck_Node);
6825 Null_Range : Boolean;
6826 Out_Of_Range_L : Boolean;
6827 Out_Of_Range_H : Boolean;
6830 -- Compute what is known at compile time
6832 if Known_T_LB and Known_T_HB then
6833 if Compile_Time_Known_Value (LB) then
6836 -- There's no point in checking that a bound is within its
6837 -- own range so pretend that it is known in this case. First
6838 -- deal with low bound.
6840 elsif Ekind (Etype (LB)) = E_Signed_Integer_Subtype
6841 and then Scalar_Range (Etype (LB)) = Scalar_Range (T_Typ)
6850 -- Likewise for the high bound
6852 if Compile_Time_Known_Value (HB) then
6855 elsif Ekind (Etype (HB)) = E_Signed_Integer_Subtype
6856 and then Scalar_Range (Etype (HB)) = Scalar_Range (T_Typ)
6866 -- Check for case where everything is static and we can do the
6867 -- check at compile time. This is skipped if we have an access
6868 -- type, since the access value may be null.
6870 -- ??? This code can be improved since you only need to know that
6871 -- the two respective bounds (LB & T_LB or HB & T_HB) are known at
6872 -- compile time to emit pertinent messages.
6874 if Known_T_LB and Known_T_HB and Known_LB and Known_HB
6877 -- Floating-point case
6879 if Is_Floating_Point_Type (S_Typ) then
6880 Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB);
6882 (Expr_Value_R (LB) < Expr_Value_R (T_LB))
6884 (Expr_Value_R (LB) > Expr_Value_R (T_HB));
6887 (Expr_Value_R (HB) > Expr_Value_R (T_HB))
6889 (Expr_Value_R (HB) < Expr_Value_R (T_LB));
6891 -- Fixed or discrete type case
6894 Null_Range := Expr_Value (HB) < Expr_Value (LB);
6896 (Expr_Value (LB) < Expr_Value (T_LB))
6898 (Expr_Value (LB) > Expr_Value (T_HB));
6901 (Expr_Value (HB) > Expr_Value (T_HB))
6903 (Expr_Value (HB) < Expr_Value (T_LB));
6906 if not Null_Range then
6907 if Out_Of_Range_L then
6908 if No (Warn_Node) then
6910 (Compile_Time_Constraint_Error
6911 (Low_Bound (Ck_Node),
6912 "static value out of range of}?", T_Typ));
6916 (Compile_Time_Constraint_Error
6918 "static range out of bounds of}?", T_Typ));
6922 if Out_Of_Range_H then
6923 if No (Warn_Node) then
6925 (Compile_Time_Constraint_Error
6926 (High_Bound (Ck_Node),
6927 "static value out of range of}?", T_Typ));
6931 (Compile_Time_Constraint_Error
6933 "static range out of bounds of}?", T_Typ));
6940 LB : Node_Id := Low_Bound (Ck_Node);
6941 HB : Node_Id := High_Bound (Ck_Node);
6944 -- If either bound is a discriminant and we are within the
6945 -- record declaration, it is a use of the discriminant in a
6946 -- constraint of a component, and nothing can be checked
6947 -- here. The check will be emitted within the init proc.
6948 -- Before then, the discriminal has no real meaning.
6949 -- Similarly, if the entity is a discriminal, there is no
6950 -- check to perform yet.
6952 -- The same holds within a discriminated synchronized type,
6953 -- where the discriminant may constrain a component or an
6956 if Nkind (LB) = N_Identifier
6957 and then Denotes_Discriminant (LB, True)
6959 if Current_Scope = Scope (Entity (LB))
6960 or else Is_Concurrent_Type (Current_Scope)
6961 or else Ekind (Entity (LB)) /= E_Discriminant
6966 New_Occurrence_Of (Discriminal (Entity (LB)), Loc);
6970 if Nkind (HB) = N_Identifier
6971 and then Denotes_Discriminant (HB, True)
6973 if Current_Scope = Scope (Entity (HB))
6974 or else Is_Concurrent_Type (Current_Scope)
6975 or else Ekind (Entity (HB)) /= E_Discriminant
6980 New_Occurrence_Of (Discriminal (Entity (HB)), Loc);
6984 Cond := Discrete_Range_Cond (Ck_Node, T_Typ);
6985 Set_Paren_Count (Cond, 1);
6991 Left_Opnd => Duplicate_Subexpr_No_Checks (HB),
6992 Right_Opnd => Duplicate_Subexpr_No_Checks (LB)),
6993 Right_Opnd => Cond);
6998 elsif Is_Scalar_Type (S_Typ) then
7000 -- This somewhat duplicates what Apply_Scalar_Range_Check does,
7001 -- except the above simply sets a flag in the node and lets
7002 -- gigi generate the check base on the Etype of the expression.
7003 -- Sometimes, however we want to do a dynamic check against an
7004 -- arbitrary target type, so we do that here.
7006 if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then
7007 Cond := Discrete_Expr_Cond (Ck_Node, T_Typ);
7009 -- For literals, we can tell if the constraint error will be
7010 -- raised at compile time, so we never need a dynamic check, but
7011 -- if the exception will be raised, then post the usual warning,
7012 -- and replace the literal with a raise constraint error
7013 -- expression. As usual, skip this for access types
7015 elsif Compile_Time_Known_Value (Ck_Node)
7016 and then not Do_Access
7019 LB : constant Node_Id := Type_Low_Bound (T_Typ);
7020 UB : constant Node_Id := Type_High_Bound (T_Typ);
7022 Out_Of_Range : Boolean;
7023 Static_Bounds : constant Boolean :=
7024 Compile_Time_Known_Value (LB)
7025 and Compile_Time_Known_Value (UB);
7028 -- Following range tests should use Sem_Eval routine ???
7030 if Static_Bounds then
7031 if Is_Floating_Point_Type (S_Typ) then
7033 (Expr_Value_R (Ck_Node) < Expr_Value_R (LB))
7035 (Expr_Value_R (Ck_Node) > Expr_Value_R (UB));
7037 -- Fixed or discrete type
7041 Expr_Value (Ck_Node) < Expr_Value (LB)
7043 Expr_Value (Ck_Node) > Expr_Value (UB);
7046 -- Bounds of the type are static and the literal is out of
7047 -- range so output a warning message.
7049 if Out_Of_Range then
7050 if No (Warn_Node) then
7052 (Compile_Time_Constraint_Error
7054 "static value out of range of}?", T_Typ));
7058 (Compile_Time_Constraint_Error
7060 "static value out of range of}?", T_Typ));
7065 Cond := Discrete_Expr_Cond (Ck_Node, T_Typ);
7069 -- Here for the case of a non-static expression, we need a runtime
7070 -- check unless the source type range is guaranteed to be in the
7071 -- range of the target type.
7074 if not In_Subrange_Of (S_Typ, T_Typ) then
7075 Cond := Discrete_Expr_Cond (Ck_Node, T_Typ);
7080 if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then
7081 if Is_Constrained (T_Typ) then
7083 Expr_Actual := Get_Referenced_Object (Ck_Node);
7084 Exptyp := Get_Actual_Subtype (Expr_Actual);
7086 if Is_Access_Type (Exptyp) then
7087 Exptyp := Designated_Type (Exptyp);
7090 -- String_Literal case. This needs to be handled specially be-
7091 -- cause no index types are available for string literals. The
7092 -- condition is simply:
7094 -- T_Typ'Length = string-literal-length
7096 if Nkind (Expr_Actual) = N_String_Literal then
7099 -- General array case. Here we have a usable actual subtype for
7100 -- the expression, and the condition is built from the two types
7102 -- T_Typ'First < Exptyp'First or else
7103 -- T_Typ'Last > Exptyp'Last or else
7104 -- T_Typ'First(1) < Exptyp'First(1) or else
7105 -- T_Typ'Last(1) > Exptyp'Last(1) or else
7108 elsif Is_Constrained (Exptyp) then
7110 Ndims : constant Nat := Number_Dimensions (T_Typ);
7116 L_Index := First_Index (T_Typ);
7117 R_Index := First_Index (Exptyp);
7119 for Indx in 1 .. Ndims loop
7120 if not (Nkind (L_Index) = N_Raise_Constraint_Error
7122 Nkind (R_Index) = N_Raise_Constraint_Error)
7124 -- Deal with compile time length check. Note that we
7125 -- skip this in the access case, because the access
7126 -- value may be null, so we cannot know statically.
7129 Subtypes_Statically_Match
7130 (Etype (L_Index), Etype (R_Index))
7132 -- If the target type is constrained then we
7133 -- have to check for exact equality of bounds
7134 -- (required for qualified expressions).
7136 if Is_Constrained (T_Typ) then
7139 Range_Equal_E_Cond (Exptyp, T_Typ, Indx));
7142 (Cond, Range_E_Cond (Exptyp, T_Typ, Indx));
7152 -- Handle cases where we do not get a usable actual subtype that
7153 -- is constrained. This happens for example in the function call
7154 -- and explicit dereference cases. In these cases, we have to get
7155 -- the length or range from the expression itself, making sure we
7156 -- do not evaluate it more than once.
7158 -- Here Ck_Node is the original expression, or more properly the
7159 -- result of applying Duplicate_Expr to the original tree,
7160 -- forcing the result to be a name.
7164 Ndims : constant Nat := Number_Dimensions (T_Typ);
7167 -- Build the condition for the explicit dereference case
7169 for Indx in 1 .. Ndims loop
7171 (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx));
7177 -- For a conversion to an unconstrained array type, generate an
7178 -- Action to check that the bounds of the source value are within
7179 -- the constraints imposed by the target type (RM 4.6(38)). No
7180 -- check is needed for a conversion to an access to unconstrained
7181 -- array type, as 4.6(24.15/2) requires the designated subtypes
7182 -- of the two access types to statically match.
7184 if Nkind (Parent (Ck_Node)) = N_Type_Conversion
7185 and then not Do_Access
7188 Opnd_Index : Node_Id;
7189 Targ_Index : Node_Id;
7190 Opnd_Range : Node_Id;
7193 Opnd_Index := First_Index (Get_Actual_Subtype (Ck_Node));
7194 Targ_Index := First_Index (T_Typ);
7195 while Present (Opnd_Index) loop
7197 -- If the index is a range, use its bounds. If it is an
7198 -- entity (as will be the case if it is a named subtype
7199 -- or an itype created for a slice) retrieve its range.
7201 if Is_Entity_Name (Opnd_Index)
7202 and then Is_Type (Entity (Opnd_Index))
7204 Opnd_Range := Scalar_Range (Entity (Opnd_Index));
7206 Opnd_Range := Opnd_Index;
7209 if Nkind (Opnd_Range) = N_Range then
7211 (Low_Bound (Opnd_Range), Etype (Targ_Index),
7212 Assume_Valid => True)
7215 (High_Bound (Opnd_Range), Etype (Targ_Index),
7216 Assume_Valid => True)
7220 -- If null range, no check needed
7223 Compile_Time_Known_Value (High_Bound (Opnd_Range))
7225 Compile_Time_Known_Value (Low_Bound (Opnd_Range))
7227 Expr_Value (High_Bound (Opnd_Range)) <
7228 Expr_Value (Low_Bound (Opnd_Range))
7232 elsif Is_Out_Of_Range
7233 (Low_Bound (Opnd_Range), Etype (Targ_Index),
7234 Assume_Valid => True)
7237 (High_Bound (Opnd_Range), Etype (Targ_Index),
7238 Assume_Valid => True)
7241 (Compile_Time_Constraint_Error
7242 (Wnode, "value out of range of}?", T_Typ));
7248 (Opnd_Range, Etype (Targ_Index)));
7252 Next_Index (Opnd_Index);
7253 Next_Index (Targ_Index);
7260 -- Construct the test and insert into the tree
7262 if Present (Cond) then
7264 Cond := Guard_Access (Cond, Loc, Ck_Node);
7268 (Make_Raise_Constraint_Error (Loc,
7270 Reason => CE_Range_Check_Failed));
7274 end Selected_Range_Checks;
7276 -------------------------------
7277 -- Storage_Checks_Suppressed --
7278 -------------------------------
7280 function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is
7282 if Present (E) and then Checks_May_Be_Suppressed (E) then
7283 return Is_Check_Suppressed (E, Storage_Check);
7285 return Scope_Suppress (Storage_Check);
7287 end Storage_Checks_Suppressed;
7289 ---------------------------
7290 -- Tag_Checks_Suppressed --
7291 ---------------------------
7293 function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is
7296 if Kill_Tag_Checks (E) then
7298 elsif Checks_May_Be_Suppressed (E) then
7299 return Is_Check_Suppressed (E, Tag_Check);
7303 return Scope_Suppress (Tag_Check);
7304 end Tag_Checks_Suppressed;
7306 --------------------------
7307 -- Validity_Check_Range --
7308 --------------------------
7310 procedure Validity_Check_Range (N : Node_Id) is
7312 if Validity_Checks_On and Validity_Check_Operands then
7313 if Nkind (N) = N_Range then
7314 Ensure_Valid (Low_Bound (N));
7315 Ensure_Valid (High_Bound (N));
7318 end Validity_Check_Range;
7320 --------------------------------
7321 -- Validity_Checks_Suppressed --
7322 --------------------------------
7324 function Validity_Checks_Suppressed (E : Entity_Id) return Boolean is
7326 if Present (E) and then Checks_May_Be_Suppressed (E) then
7327 return Is_Check_Suppressed (E, Validity_Check);
7329 return Scope_Suppress (Validity_Check);
7331 end Validity_Checks_Suppressed;