1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2003 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 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 with Atree; use Atree;
28 with Debug; use Debug;
29 with Einfo; use Einfo;
30 with Errout; use Errout;
31 with Exp_Ch2; use Exp_Ch2;
32 with Exp_Util; use Exp_Util;
33 with Elists; use Elists;
34 with Freeze; use Freeze;
36 with Nlists; use Nlists;
37 with Nmake; use Nmake;
39 with Output; use Output;
40 with Restrict; use Restrict;
41 with Rtsfind; use Rtsfind;
43 with Sem_Eval; use Sem_Eval;
44 with Sem_Ch8; use Sem_Ch8;
45 with Sem_Res; use Sem_Res;
46 with Sem_Util; use Sem_Util;
47 with Sem_Warn; use Sem_Warn;
48 with Sinfo; use Sinfo;
49 with Sinput; use Sinput;
50 with Snames; use Snames;
51 with Sprint; use Sprint;
52 with Stand; use Stand;
53 with Targparm; use Targparm;
54 with Tbuild; use Tbuild;
55 with Ttypes; use Ttypes;
56 with Urealp; use Urealp;
57 with Validsw; use Validsw;
59 package body Checks is
61 -- General note: many of these routines are concerned with generating
62 -- checking code to make sure that constraint error is raised at runtime.
63 -- Clearly this code is only needed if the expander is active, since
64 -- otherwise we will not be generating code or going into the runtime
67 -- We therefore disconnect most of these checks if the expander is
68 -- inactive. This has the additional benefit that we do not need to
69 -- worry about the tree being messed up by previous errors (since errors
70 -- turn off expansion anyway).
72 -- There are a few exceptions to the above rule. For instance routines
73 -- such as Apply_Scalar_Range_Check that do not insert any code can be
74 -- safely called even when the Expander is inactive (but Errors_Detected
75 -- is 0). The benefit of executing this code when expansion is off, is
76 -- the ability to emit constraint error warning for static expressions
77 -- even when we are not generating code.
79 -------------------------------------
80 -- Suppression of Redundant Checks --
81 -------------------------------------
83 -- This unit implements a limited circuit for removal of redundant
84 -- checks. The processing is based on a tracing of simple sequential
85 -- flow. For any sequence of statements, we save expressions that are
86 -- marked to be checked, and then if the same expression appears later
87 -- with the same check, then under certain circumstances, the second
88 -- check can be suppressed.
90 -- Basically, we can suppress the check if we know for certain that
91 -- the previous expression has been elaborated (together with its
92 -- check), and we know that the exception frame is the same, and that
93 -- nothing has happened to change the result of the exception.
95 -- Let us examine each of these three conditions in turn to describe
96 -- how we ensure that this condition is met.
98 -- First, we need to know for certain that the previous expression has
99 -- been executed. This is done principly by the mechanism of calling
100 -- Conditional_Statements_Begin at the start of any statement sequence
101 -- and Conditional_Statements_End at the end. The End call causes all
102 -- checks remembered since the Begin call to be discarded. This does
103 -- miss a few cases, notably the case of a nested BEGIN-END block with
104 -- no exception handlers. But the important thing is to be conservative.
105 -- The other protection is that all checks are discarded if a label
106 -- is encountered, since then the assumption of sequential execution
107 -- is violated, and we don't know enough about the flow.
109 -- Second, we need to know that the exception frame is the same. We
110 -- do this by killing all remembered checks when we enter a new frame.
111 -- Again, that's over-conservative, but generally the cases we can help
112 -- with are pretty local anyway (like the body of a loop for example).
114 -- Third, we must be sure to forget any checks which are no longer valid.
115 -- This is done by two mechanisms, first the Kill_Checks_Variable call is
116 -- used to note any changes to local variables. We only attempt to deal
117 -- with checks involving local variables, so we do not need to worry
118 -- about global variables. Second, a call to any non-global procedure
119 -- causes us to abandon all stored checks, since such a all may affect
120 -- the values of any local variables.
122 -- The following define the data structures used to deal with remembering
123 -- checks so that redundant checks can be eliminated as described above.
125 -- Right now, the only expressions that we deal with are of the form of
126 -- simple local objects (either declared locally, or IN parameters) or
127 -- such objects plus/minus a compile time known constant. We can do
128 -- more later on if it seems worthwhile, but this catches many simple
129 -- cases in practice.
131 -- The following record type reflects a single saved check. An entry
132 -- is made in the stack of saved checks if and only if the expression
133 -- has been elaborated with the indicated checks.
135 type Saved_Check is record
137 -- Set True if entry is killed by Kill_Checks
140 -- The entity involved in the expression that is checked
143 -- A compile time value indicating the result of adding or
144 -- subtracting a compile time value. This value is to be
145 -- added to the value of the Entity. A value of zero is
146 -- used for the case of a simple entity reference.
148 Check_Type : Character;
149 -- This is set to 'R' for a range check (in which case Target_Type
150 -- is set to the target type for the range check) or to 'O' for an
151 -- overflow check (in which case Target_Type is set to Empty).
153 Target_Type : Entity_Id;
154 -- Used only if Do_Range_Check is set. Records the target type for
155 -- the check. We need this, because a check is a duplicate only if
156 -- it has a the same target type (or more accurately one with a
157 -- range that is smaller or equal to the stored target type of a
161 -- The following table keeps track of saved checks. Rather than use an
162 -- extensible table. We just use a table of fixed size, and we discard
163 -- any saved checks that do not fit. That's very unlikely to happen and
164 -- this is only an optimization in any case.
166 Saved_Checks : array (Int range 1 .. 200) of Saved_Check;
167 -- Array of saved checks
169 Num_Saved_Checks : Nat := 0;
170 -- Number of saved checks
172 -- The following stack keeps track of statement ranges. It is treated
173 -- as a stack. When Conditional_Statements_Begin is called, an entry
174 -- is pushed onto this stack containing the value of Num_Saved_Checks
175 -- at the time of the call. Then when Conditional_Statements_End is
176 -- called, this value is popped off and used to reset Num_Saved_Checks.
178 -- Note: again, this is a fixed length stack with a size that should
179 -- always be fine. If the value of the stack pointer goes above the
180 -- limit, then we just forget all saved checks.
182 Saved_Checks_Stack : array (Int range 1 .. 100) of Nat;
183 Saved_Checks_TOS : Nat := 0;
185 -----------------------
186 -- Local Subprograms --
187 -----------------------
189 procedure Apply_Selected_Length_Checks
191 Target_Typ : Entity_Id;
192 Source_Typ : Entity_Id;
193 Do_Static : Boolean);
194 -- This is the subprogram that does all the work for Apply_Length_Check
195 -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as
196 -- described for the above routines. The Do_Static flag indicates that
197 -- only a static check is to be done.
199 procedure Apply_Selected_Range_Checks
201 Target_Typ : Entity_Id;
202 Source_Typ : Entity_Id;
203 Do_Static : Boolean);
204 -- This is the subprogram that does all the work for Apply_Range_Check.
205 -- Expr, Target_Typ and Source_Typ are as described for the above
206 -- routine. The Do_Static flag indicates that only a static check is
211 Check_Type : Character;
212 Target_Type : Entity_Id;
213 Entry_OK : out Boolean;
217 -- This routine is used by Enable_Range_Check and Enable_Overflow_Check
218 -- to see if a check is of the form for optimization, and if so, to see
219 -- if it has already been performed. Expr is the expression to check,
220 -- and Check_Type is 'R' for a range check, 'O' for an overflow check.
221 -- Target_Type is the target type for a range check, and Empty for an
222 -- overflow check. If the entry is not of the form for optimization,
223 -- then Entry_OK is set to False, and the remaining out parameters
224 -- are undefined. If the entry is OK, then Ent/Ofs are set to the
225 -- entity and offset from the expression. Check_Num is the number of
226 -- a matching saved entry in Saved_Checks, or zero if no such entry
229 function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id;
230 -- If a discriminal is used in constraining a prival, Return reference
231 -- to the discriminal of the protected body (which renames the parameter
232 -- of the enclosing protected operation). This clumsy transformation is
233 -- needed because privals are created too late and their actual subtypes
234 -- are not available when analysing the bodies of the protected operations.
235 -- To be cleaned up???
237 function Guard_Access
242 -- In the access type case, guard the test with a test to ensure
243 -- that the access value is non-null, since the checks do not
244 -- not apply to null access values.
246 procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr);
247 -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the
248 -- Constraint_Error node.
250 function Selected_Length_Checks
252 Target_Typ : Entity_Id;
253 Source_Typ : Entity_Id;
256 -- Like Apply_Selected_Length_Checks, except it doesn't modify
257 -- anything, just returns a list of nodes as described in the spec of
258 -- this package for the Range_Check function.
260 function Selected_Range_Checks
262 Target_Typ : Entity_Id;
263 Source_Typ : Entity_Id;
266 -- Like Apply_Selected_Range_Checks, except it doesn't modify anything,
267 -- just returns a list of nodes as described in the spec of this package
268 -- for the Range_Check function.
270 ------------------------------
271 -- Access_Checks_Suppressed --
272 ------------------------------
274 function Access_Checks_Suppressed (E : Entity_Id) return Boolean is
276 if Present (E) and then Checks_May_Be_Suppressed (E) then
277 return Is_Check_Suppressed (E, Access_Check);
279 return Scope_Suppress (Access_Check);
281 end Access_Checks_Suppressed;
283 -------------------------------------
284 -- Accessibility_Checks_Suppressed --
285 -------------------------------------
287 function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is
289 if Present (E) and then Checks_May_Be_Suppressed (E) then
290 return Is_Check_Suppressed (E, Accessibility_Check);
292 return Scope_Suppress (Accessibility_Check);
294 end Accessibility_Checks_Suppressed;
296 -------------------------
297 -- Append_Range_Checks --
298 -------------------------
300 procedure Append_Range_Checks
301 (Checks : Check_Result;
303 Suppress_Typ : Entity_Id;
304 Static_Sloc : Source_Ptr;
307 Internal_Flag_Node : constant Node_Id := Flag_Node;
308 Internal_Static_Sloc : constant Source_Ptr := Static_Sloc;
310 Checks_On : constant Boolean :=
311 (not Index_Checks_Suppressed (Suppress_Typ))
313 (not Range_Checks_Suppressed (Suppress_Typ));
316 -- For now we just return if Checks_On is false, however this should
317 -- be enhanced to check for an always True value in the condition
318 -- and to generate a compilation warning???
320 if not Checks_On then
325 exit when No (Checks (J));
327 if Nkind (Checks (J)) = N_Raise_Constraint_Error
328 and then Present (Condition (Checks (J)))
330 if not Has_Dynamic_Range_Check (Internal_Flag_Node) then
331 Append_To (Stmts, Checks (J));
332 Set_Has_Dynamic_Range_Check (Internal_Flag_Node);
338 Make_Raise_Constraint_Error (Internal_Static_Sloc,
339 Reason => CE_Range_Check_Failed));
342 end Append_Range_Checks;
344 ------------------------
345 -- Apply_Access_Check --
346 ------------------------
348 procedure Apply_Access_Check (N : Node_Id) is
349 P : constant Node_Id := Prefix (N);
352 if Inside_A_Generic then
356 if Is_Entity_Name (P) then
357 Check_Unset_Reference (P);
360 -- Don't need access check if prefix is known to be non-null
362 if Known_Non_Null (P) then
365 -- Don't need access checks if they are suppressed on the type
367 elsif Access_Checks_Suppressed (Etype (P)) then
371 -- Case where P is an entity name
373 if Is_Entity_Name (P) then
375 Ent : constant Entity_Id := Entity (P);
378 if Access_Checks_Suppressed (Ent) then
382 -- Otherwise we are going to generate an access check, and
383 -- are we have done it, the entity will now be known non null
384 -- But we have to check for safe sequential semantics here!
386 if Safe_To_Capture_Value (N, Ent) then
387 Set_Is_Known_Non_Null (Ent);
392 -- Access check is required
395 Loc : constant Source_Ptr := Sloc (N);
399 Make_Raise_Constraint_Error (Sloc (N),
402 Left_Opnd => Duplicate_Subexpr_Move_Checks (P),
405 Reason => CE_Access_Check_Failed));
407 end Apply_Access_Check;
409 -------------------------------
410 -- Apply_Accessibility_Check --
411 -------------------------------
413 procedure Apply_Accessibility_Check (N : Node_Id; Typ : Entity_Id) is
414 Loc : constant Source_Ptr := Sloc (N);
415 Param_Ent : constant Entity_Id := Param_Entity (N);
416 Param_Level : Node_Id;
417 Type_Level : Node_Id;
420 if Inside_A_Generic then
423 -- Only apply the run-time check if the access parameter
424 -- has an associated extra access level parameter and
425 -- when the level of the type is less deep than the level
426 -- of the access parameter.
428 elsif Present (Param_Ent)
429 and then Present (Extra_Accessibility (Param_Ent))
430 and then UI_Gt (Object_Access_Level (N),
431 Type_Access_Level (Typ))
432 and then not Accessibility_Checks_Suppressed (Param_Ent)
433 and then not Accessibility_Checks_Suppressed (Typ)
436 New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc);
439 Make_Integer_Literal (Loc, Type_Access_Level (Typ));
441 -- Raise Program_Error if the accessibility level of the
442 -- the access parameter is deeper than the level of the
443 -- target access type.
446 Make_Raise_Program_Error (Loc,
449 Left_Opnd => Param_Level,
450 Right_Opnd => Type_Level),
451 Reason => PE_Accessibility_Check_Failed));
453 Analyze_And_Resolve (N);
455 end Apply_Accessibility_Check;
457 ---------------------------
458 -- Apply_Alignment_Check --
459 ---------------------------
461 procedure Apply_Alignment_Check (E : Entity_Id; N : Node_Id) is
462 AC : constant Node_Id := Address_Clause (E);
467 -- See if check needed. Note that we never need a check if the
468 -- maximum alignment is one, since the check will always succeed
471 or else not Check_Address_Alignment (AC)
472 or else Maximum_Alignment = 1
478 Expr := Expression (AC);
480 if Nkind (Expr) = N_Unchecked_Type_Conversion then
481 Expr := Expression (Expr);
483 elsif Nkind (Expr) = N_Function_Call
484 and then Is_RTE (Entity (Name (Expr)), RE_To_Address)
486 Expr := First (Parameter_Associations (Expr));
488 if Nkind (Expr) = N_Parameter_Association then
489 Expr := Explicit_Actual_Parameter (Expr);
493 -- Here Expr is the address value. See if we know that the
494 -- value is unacceptable at compile time.
496 if Compile_Time_Known_Value (Expr)
497 and then Known_Alignment (E)
499 if Expr_Value (Expr) mod Alignment (E) /= 0 then
501 Make_Raise_Program_Error (Loc,
502 Reason => PE_Misaligned_Address_Value));
504 ("?specified address for& not " &
505 "consistent with alignment", Expr, E);
508 -- Here we do not know if the value is acceptable, generate
509 -- code to raise PE if alignment is inappropriate.
512 -- Skip generation of this code if we don't want elab code
514 if not Restrictions (No_Elaboration_Code) then
515 Insert_After_And_Analyze (N,
516 Make_Raise_Program_Error (Loc,
523 (RTE (RE_Integer_Address),
524 Duplicate_Subexpr_No_Checks (Expr)),
526 Make_Attribute_Reference (Loc,
527 Prefix => New_Occurrence_Of (E, Loc),
528 Attribute_Name => Name_Alignment)),
529 Right_Opnd => Make_Integer_Literal (Loc, Uint_0)),
530 Reason => PE_Misaligned_Address_Value),
531 Suppress => All_Checks);
538 when RE_Not_Available =>
540 end Apply_Alignment_Check;
542 -------------------------------------
543 -- Apply_Arithmetic_Overflow_Check --
544 -------------------------------------
546 -- This routine is called only if the type is an integer type, and
547 -- a software arithmetic overflow check must be performed for op
548 -- (add, subtract, multiply). The check is performed only if
549 -- Software_Overflow_Checking is enabled and Do_Overflow_Check
550 -- is set. In this case we expand the operation into a more complex
551 -- sequence of tests that ensures that overflow is properly caught.
553 procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is
554 Loc : constant Source_Ptr := Sloc (N);
555 Typ : constant Entity_Id := Etype (N);
556 Rtyp : constant Entity_Id := Root_Type (Typ);
557 Siz : constant Int := UI_To_Int (Esize (Rtyp));
558 Dsiz : constant Int := Siz * 2;
565 -- Skip this if overflow checks are done in back end, or the overflow
566 -- flag is not set anyway, or we are not doing code expansion.
568 if Backend_Overflow_Checks_On_Target
569 or not Do_Overflow_Check (N)
570 or not Expander_Active
575 -- Otherwise, we generate the full general code for front end overflow
576 -- detection, which works by doing arithmetic in a larger type:
582 -- Typ (Checktyp (x) op Checktyp (y));
584 -- where Typ is the type of the original expression, and Checktyp is
585 -- an integer type of sufficient length to hold the largest possible
588 -- In the case where check type exceeds the size of Long_Long_Integer,
589 -- we use a different approach, expanding to:
591 -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y)))
593 -- where xxx is Add, Multiply or Subtract as appropriate
595 -- Find check type if one exists
597 if Dsiz <= Standard_Integer_Size then
598 Ctyp := Standard_Integer;
600 elsif Dsiz <= Standard_Long_Long_Integer_Size then
601 Ctyp := Standard_Long_Long_Integer;
603 -- No check type exists, use runtime call
606 if Nkind (N) = N_Op_Add then
607 Cent := RE_Add_With_Ovflo_Check;
609 elsif Nkind (N) = N_Op_Multiply then
610 Cent := RE_Multiply_With_Ovflo_Check;
613 pragma Assert (Nkind (N) = N_Op_Subtract);
614 Cent := RE_Subtract_With_Ovflo_Check;
619 Make_Function_Call (Loc,
620 Name => New_Reference_To (RTE (Cent), Loc),
621 Parameter_Associations => New_List (
622 OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)),
623 OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N))))));
625 Analyze_And_Resolve (N, Typ);
629 -- If we fall through, we have the case where we do the arithmetic in
630 -- the next higher type and get the check by conversion. In these cases
631 -- Ctyp is set to the type to be used as the check type.
633 Opnod := Relocate_Node (N);
635 Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod));
638 Set_Etype (Opnd, Ctyp);
639 Set_Analyzed (Opnd, True);
640 Set_Left_Opnd (Opnod, Opnd);
642 Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod));
645 Set_Etype (Opnd, Ctyp);
646 Set_Analyzed (Opnd, True);
647 Set_Right_Opnd (Opnod, Opnd);
649 -- The type of the operation changes to the base type of the check
650 -- type, and we reset the overflow check indication, since clearly
651 -- no overflow is possible now that we are using a double length
652 -- type. We also set the Analyzed flag to avoid a recursive attempt
653 -- to expand the node.
655 Set_Etype (Opnod, Base_Type (Ctyp));
656 Set_Do_Overflow_Check (Opnod, False);
657 Set_Analyzed (Opnod, True);
659 -- Now build the outer conversion
661 Opnd := OK_Convert_To (Typ, Opnod);
663 Set_Etype (Opnd, Typ);
665 -- In the discrete type case, we directly generate the range check
666 -- for the outer operand. This range check will implement the required
669 if Is_Discrete_Type (Typ) then
671 Generate_Range_Check (Expression (N), Typ, CE_Overflow_Check_Failed);
673 -- For other types, we enable overflow checking on the conversion,
674 -- after setting the node as analyzed to prevent recursive attempts
675 -- to expand the conversion node.
678 Set_Analyzed (Opnd, True);
679 Enable_Overflow_Check (Opnd);
684 when RE_Not_Available =>
686 end Apply_Arithmetic_Overflow_Check;
688 ----------------------------
689 -- Apply_Array_Size_Check --
690 ----------------------------
692 -- Note: Really of course this entre check should be in the backend,
693 -- and perhaps this is not quite the right value, but it is good
694 -- enough to catch the normal cases (and the relevant ACVC tests!)
696 procedure Apply_Array_Size_Check (N : Node_Id; Typ : Entity_Id) is
697 Loc : constant Source_Ptr := Sloc (N);
698 Ctyp : constant Entity_Id := Component_Type (Typ);
699 Ent : constant Entity_Id := Defining_Identifier (N);
711 Static : Boolean := True;
712 -- Set false if any index subtye bound is non-static
714 Umark : constant Uintp.Save_Mark := Uintp.Mark;
715 -- We can throw away all the Uint computations here, since they are
716 -- done only to generate boolean test results.
719 -- Size to check against
721 function Is_Address_Or_Import (Decl : Node_Id) return Boolean;
722 -- Determines if Decl is an address clause or Import/Interface pragma
723 -- that references the defining identifier of the current declaration.
725 --------------------------
726 -- Is_Address_Or_Import --
727 --------------------------
729 function Is_Address_Or_Import (Decl : Node_Id) return Boolean is
731 if Nkind (Decl) = N_At_Clause then
732 return Chars (Identifier (Decl)) = Chars (Ent);
734 elsif Nkind (Decl) = N_Attribute_Definition_Clause then
736 Chars (Decl) = Name_Address
738 Nkind (Name (Decl)) = N_Identifier
740 Chars (Name (Decl)) = Chars (Ent);
742 elsif Nkind (Decl) = N_Pragma then
743 if (Chars (Decl) = Name_Import
745 Chars (Decl) = Name_Interface)
746 and then Present (Pragma_Argument_Associations (Decl))
749 F : constant Node_Id :=
750 First (Pragma_Argument_Associations (Decl));
758 Nkind (Expression (Next (F))) = N_Identifier
760 Chars (Expression (Next (F))) = Chars (Ent);
770 end Is_Address_Or_Import;
772 -- Start of processing for Apply_Array_Size_Check
775 if not Expander_Active
776 or else Storage_Checks_Suppressed (Typ)
781 -- It is pointless to insert this check inside an init proc, because
782 -- that's too late, we have already built the object to be the right
783 -- size, and if it's too large, too bad!
785 if Inside_Init_Proc then
789 -- Look head for pragma interface/import or address clause applying
790 -- to this entity. If found, we suppress the check entirely. For now
791 -- we only look ahead 20 declarations to stop this becoming too slow
792 -- Note that eventually this whole routine gets moved to gigi.
795 for Ctr in 1 .. 20 loop
799 if Is_Address_Or_Import (Decl) then
804 -- First step is to calculate the maximum number of elements. For this
805 -- calculation, we use the actual size of the subtype if it is static,
806 -- and if a bound of a subtype is non-static, we go to the bound of the
810 Indx := First_Index (Typ);
811 while Present (Indx) loop
812 Xtyp := Etype (Indx);
813 Lo := Type_Low_Bound (Xtyp);
814 Hi := Type_High_Bound (Xtyp);
816 -- If any bound raises constraint error, we will never get this
817 -- far, so there is no need to generate any kind of check.
819 if Raises_Constraint_Error (Lo)
821 Raises_Constraint_Error (Hi)
823 Uintp.Release (Umark);
827 -- Otherwise get bounds values
829 if Is_Static_Expression (Lo) then
830 Lob := Expr_Value (Lo);
832 Lob := Expr_Value (Type_Low_Bound (Base_Type (Xtyp)));
836 if Is_Static_Expression (Hi) then
837 Hib := Expr_Value (Hi);
839 Hib := Expr_Value (Type_High_Bound (Base_Type (Xtyp)));
843 Siz := Siz * UI_Max (Hib - Lob + 1, Uint_0);
847 -- Compute the limit against which we want to check. For subprograms,
848 -- where the array will go on the stack, we use 8*2**24, which (in
849 -- bits) is the size of a 16 megabyte array.
851 if Is_Subprogram (Scope (Ent)) then
852 Check_Siz := Uint_2 ** 27;
854 Check_Siz := Uint_2 ** 31;
857 -- If we have all static bounds and Siz is too large, then we know we
858 -- know we have a storage error right now, so generate message
860 if Static and then Siz >= Check_Siz then
862 Make_Raise_Storage_Error (Loc,
863 Reason => SE_Object_Too_Large));
864 Error_Msg_N ("?Storage_Error will be raised at run-time", N);
865 Uintp.Release (Umark);
869 -- Case of component size known at compile time. If the array
870 -- size is definitely in range, then we do not need a check.
872 if Known_Esize (Ctyp)
873 and then Siz * Esize (Ctyp) < Check_Siz
875 Uintp.Release (Umark);
879 -- Here if a dynamic check is required
881 -- What we do is to build an expression for the size of the array,
882 -- which is computed as the 'Size of the array component, times
883 -- the size of each dimension.
885 Uintp.Release (Umark);
888 Make_Attribute_Reference (Loc,
889 Prefix => New_Occurrence_Of (Ctyp, Loc),
890 Attribute_Name => Name_Size);
892 Indx := First_Index (Typ);
894 for J in 1 .. Number_Dimensions (Typ) loop
895 if Sloc (Etype (Indx)) = Sloc (N) then
896 Ensure_Defined (Etype (Indx), N);
900 Make_Op_Multiply (Loc,
903 Make_Attribute_Reference (Loc,
904 Prefix => New_Occurrence_Of (Typ, Loc),
905 Attribute_Name => Name_Length,
906 Expressions => New_List (
907 Make_Integer_Literal (Loc, J))));
912 Make_Raise_Storage_Error (Loc,
917 Make_Integer_Literal (Loc, Check_Siz)),
918 Reason => SE_Object_Too_Large);
920 Set_Size_Check_Code (Defining_Identifier (N), Code);
921 Insert_Action (N, Code);
922 end Apply_Array_Size_Check;
924 ----------------------------
925 -- Apply_Constraint_Check --
926 ----------------------------
928 procedure Apply_Constraint_Check
931 No_Sliding : Boolean := False)
933 Desig_Typ : Entity_Id;
936 if Inside_A_Generic then
939 elsif Is_Scalar_Type (Typ) then
940 Apply_Scalar_Range_Check (N, Typ);
942 elsif Is_Array_Type (Typ) then
944 -- A useful optimization: an aggregate with only an Others clause
945 -- always has the right bounds.
947 if Nkind (N) = N_Aggregate
948 and then No (Expressions (N))
950 (First (Choices (First (Component_Associations (N)))))
956 if Is_Constrained (Typ) then
957 Apply_Length_Check (N, Typ);
960 Apply_Range_Check (N, Typ);
963 Apply_Range_Check (N, Typ);
966 elsif (Is_Record_Type (Typ)
967 or else Is_Private_Type (Typ))
968 and then Has_Discriminants (Base_Type (Typ))
969 and then Is_Constrained (Typ)
971 Apply_Discriminant_Check (N, Typ);
973 elsif Is_Access_Type (Typ) then
975 Desig_Typ := Designated_Type (Typ);
977 -- No checks necessary if expression statically null
979 if Nkind (N) = N_Null then
982 -- No sliding possible on access to arrays
984 elsif Is_Array_Type (Desig_Typ) then
985 if Is_Constrained (Desig_Typ) then
986 Apply_Length_Check (N, Typ);
989 Apply_Range_Check (N, Typ);
991 elsif Has_Discriminants (Base_Type (Desig_Typ))
992 and then Is_Constrained (Desig_Typ)
994 Apply_Discriminant_Check (N, Typ);
997 end Apply_Constraint_Check;
999 ------------------------------
1000 -- Apply_Discriminant_Check --
1001 ------------------------------
1003 procedure Apply_Discriminant_Check
1006 Lhs : Node_Id := Empty)
1008 Loc : constant Source_Ptr := Sloc (N);
1009 Do_Access : constant Boolean := Is_Access_Type (Typ);
1010 S_Typ : Entity_Id := Etype (N);
1014 function Is_Aliased_Unconstrained_Component return Boolean;
1015 -- It is possible for an aliased component to have a nominal
1016 -- unconstrained subtype (through instantiation). If this is a
1017 -- discriminated component assigned in the expansion of an aggregate
1018 -- in an initialization, the check must be suppressed. This unusual
1019 -- situation requires a predicate of its own (see 7503-008).
1021 ----------------------------------------
1022 -- Is_Aliased_Unconstrained_Component --
1023 ----------------------------------------
1025 function Is_Aliased_Unconstrained_Component return Boolean is
1030 if Nkind (Lhs) /= N_Selected_Component then
1033 Comp := Entity (Selector_Name (Lhs));
1034 Pref := Prefix (Lhs);
1037 if Ekind (Comp) /= E_Component
1038 or else not Is_Aliased (Comp)
1043 return not Comes_From_Source (Pref)
1044 and then In_Instance
1045 and then not Is_Constrained (Etype (Comp));
1046 end Is_Aliased_Unconstrained_Component;
1048 -- Start of processing for Apply_Discriminant_Check
1052 T_Typ := Designated_Type (Typ);
1057 -- Nothing to do if discriminant checks are suppressed or else no code
1058 -- is to be generated
1060 if not Expander_Active
1061 or else Discriminant_Checks_Suppressed (T_Typ)
1066 -- No discriminant checks necessary for access when expression
1067 -- is statically Null. This is not only an optimization, this is
1068 -- fundamental because otherwise discriminant checks may be generated
1069 -- in init procs for types containing an access to a non-frozen yet
1070 -- record, causing a deadly forward reference.
1072 -- Also, if the expression is of an access type whose designated
1073 -- type is incomplete, then the access value must be null and
1074 -- we suppress the check.
1076 if Nkind (N) = N_Null then
1079 elsif Is_Access_Type (S_Typ) then
1080 S_Typ := Designated_Type (S_Typ);
1082 if Ekind (S_Typ) = E_Incomplete_Type then
1087 -- If an assignment target is present, then we need to generate
1088 -- the actual subtype if the target is a parameter or aliased
1089 -- object with an unconstrained nominal subtype.
1092 and then (Present (Param_Entity (Lhs))
1093 or else (not Is_Constrained (T_Typ)
1094 and then Is_Aliased_View (Lhs)
1095 and then not Is_Aliased_Unconstrained_Component))
1097 T_Typ := Get_Actual_Subtype (Lhs);
1100 -- Nothing to do if the type is unconstrained (this is the case
1101 -- where the actual subtype in the RM sense of N is unconstrained
1102 -- and no check is required).
1104 if not Is_Constrained (T_Typ) then
1108 -- Suppress checks if the subtypes are the same.
1109 -- the check must be preserved in an assignment to a formal, because
1110 -- the constraint is given by the actual.
1112 if Nkind (Original_Node (N)) /= N_Allocator
1114 or else not Is_Entity_Name (Lhs)
1115 or else No (Param_Entity (Lhs)))
1118 or else (Do_Access and then Designated_Type (Typ) = S_Typ))
1119 and then not Is_Aliased_View (Lhs)
1124 -- We can also eliminate checks on allocators with a subtype mark
1125 -- that coincides with the context type. The context type may be a
1126 -- subtype without a constraint (common case, a generic actual).
1128 elsif Nkind (Original_Node (N)) = N_Allocator
1129 and then Is_Entity_Name (Expression (Original_Node (N)))
1132 Alloc_Typ : constant Entity_Id :=
1133 Entity (Expression (Original_Node (N)));
1136 if Alloc_Typ = T_Typ
1137 or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration
1138 and then Is_Entity_Name (
1139 Subtype_Indication (Parent (T_Typ)))
1140 and then Alloc_Typ = Base_Type (T_Typ))
1148 -- See if we have a case where the types are both constrained, and
1149 -- all the constraints are constants. In this case, we can do the
1150 -- check successfully at compile time.
1152 -- We skip this check for the case where the node is a rewritten`
1153 -- allocator, because it already carries the context subtype, and
1154 -- extracting the discriminants from the aggregate is messy.
1156 if Is_Constrained (S_Typ)
1157 and then Nkind (Original_Node (N)) /= N_Allocator
1167 -- S_Typ may not have discriminants in the case where it is a
1168 -- private type completed by a default discriminated type. In
1169 -- that case, we need to get the constraints from the
1170 -- underlying_type. If the underlying type is unconstrained (i.e.
1171 -- has no default discriminants) no check is needed.
1173 if Has_Discriminants (S_Typ) then
1174 Discr := First_Discriminant (S_Typ);
1175 DconS := First_Elmt (Discriminant_Constraint (S_Typ));
1178 Discr := First_Discriminant (Underlying_Type (S_Typ));
1181 (Discriminant_Constraint (Underlying_Type (S_Typ)));
1187 -- A further optimization: if T_Typ is derived from S_Typ
1188 -- without imposing a constraint, no check is needed.
1190 if Nkind (Original_Node (Parent (T_Typ))) =
1191 N_Full_Type_Declaration
1194 Type_Def : Node_Id :=
1196 (Original_Node (Parent (T_Typ)));
1198 if Nkind (Type_Def) = N_Derived_Type_Definition
1199 and then Is_Entity_Name (Subtype_Indication (Type_Def))
1200 and then Entity (Subtype_Indication (Type_Def)) = S_Typ
1208 DconT := First_Elmt (Discriminant_Constraint (T_Typ));
1210 while Present (Discr) loop
1211 ItemS := Node (DconS);
1212 ItemT := Node (DconT);
1215 not Is_OK_Static_Expression (ItemS)
1217 not Is_OK_Static_Expression (ItemT);
1219 if Expr_Value (ItemS) /= Expr_Value (ItemT) then
1220 if Do_Access then -- needs run-time check.
1223 Apply_Compile_Time_Constraint_Error
1224 (N, "incorrect value for discriminant&?",
1225 CE_Discriminant_Check_Failed, Ent => Discr);
1232 Next_Discriminant (Discr);
1241 -- Here we need a discriminant check. First build the expression
1242 -- for the comparisons of the discriminants:
1244 -- (n.disc1 /= typ.disc1) or else
1245 -- (n.disc2 /= typ.disc2) or else
1247 -- (n.discn /= typ.discn)
1249 Cond := Build_Discriminant_Checks (N, T_Typ);
1251 -- If Lhs is set and is a parameter, then the condition is
1252 -- guarded by: lhs'constrained and then (condition built above)
1254 if Present (Param_Entity (Lhs)) then
1258 Make_Attribute_Reference (Loc,
1259 Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc),
1260 Attribute_Name => Name_Constrained),
1261 Right_Opnd => Cond);
1265 Cond := Guard_Access (Cond, Loc, N);
1269 Make_Raise_Constraint_Error (Loc,
1271 Reason => CE_Discriminant_Check_Failed));
1272 end Apply_Discriminant_Check;
1274 ------------------------
1275 -- Apply_Divide_Check --
1276 ------------------------
1278 procedure Apply_Divide_Check (N : Node_Id) is
1279 Loc : constant Source_Ptr := Sloc (N);
1280 Typ : constant Entity_Id := Etype (N);
1281 Left : constant Node_Id := Left_Opnd (N);
1282 Right : constant Node_Id := Right_Opnd (N);
1294 and not Backend_Divide_Checks_On_Target
1296 Determine_Range (Right, ROK, Rlo, Rhi);
1298 -- See if division by zero possible, and if so generate test. This
1299 -- part of the test is not controlled by the -gnato switch.
1301 if Do_Division_Check (N) then
1303 if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then
1305 Make_Raise_Constraint_Error (Loc,
1308 Left_Opnd => Duplicate_Subexpr_Move_Checks (Right),
1309 Right_Opnd => Make_Integer_Literal (Loc, 0)),
1310 Reason => CE_Divide_By_Zero));
1314 -- Test for extremely annoying case of xxx'First divided by -1
1316 if Do_Overflow_Check (N) then
1318 if Nkind (N) = N_Op_Divide
1319 and then Is_Signed_Integer_Type (Typ)
1321 Determine_Range (Left, LOK, Llo, Lhi);
1322 LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ)));
1324 if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi))
1326 ((not LOK) or else (Llo = LLB))
1329 Make_Raise_Constraint_Error (Loc,
1335 Duplicate_Subexpr_Move_Checks (Left),
1336 Right_Opnd => Make_Integer_Literal (Loc, LLB)),
1340 Duplicate_Subexpr (Right),
1342 Make_Integer_Literal (Loc, -1))),
1343 Reason => CE_Overflow_Check_Failed));
1348 end Apply_Divide_Check;
1350 ------------------------
1351 -- Apply_Length_Check --
1352 ------------------------
1354 procedure Apply_Length_Check
1356 Target_Typ : Entity_Id;
1357 Source_Typ : Entity_Id := Empty)
1360 Apply_Selected_Length_Checks
1361 (Ck_Node, Target_Typ, Source_Typ, Do_Static => False);
1362 end Apply_Length_Check;
1364 -----------------------
1365 -- Apply_Range_Check --
1366 -----------------------
1368 procedure Apply_Range_Check
1370 Target_Typ : Entity_Id;
1371 Source_Typ : Entity_Id := Empty)
1374 Apply_Selected_Range_Checks
1375 (Ck_Node, Target_Typ, Source_Typ, Do_Static => False);
1376 end Apply_Range_Check;
1378 ------------------------------
1379 -- Apply_Scalar_Range_Check --
1380 ------------------------------
1382 -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check
1383 -- flag off if it is already set on.
1385 procedure Apply_Scalar_Range_Check
1387 Target_Typ : Entity_Id;
1388 Source_Typ : Entity_Id := Empty;
1389 Fixed_Int : Boolean := False)
1391 Parnt : constant Node_Id := Parent (Expr);
1393 Arr : Node_Id := Empty; -- initialize to prevent warning
1394 Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning
1397 Is_Subscr_Ref : Boolean;
1398 -- Set true if Expr is a subscript
1400 Is_Unconstrained_Subscr_Ref : Boolean;
1401 -- Set true if Expr is a subscript of an unconstrained array. In this
1402 -- case we do not attempt to do an analysis of the value against the
1403 -- range of the subscript, since we don't know the actual subtype.
1406 -- Set to True if Expr should be regarded as a real value
1407 -- even though the type of Expr might be discrete.
1409 procedure Bad_Value;
1410 -- Procedure called if value is determined to be out of range
1416 procedure Bad_Value is
1418 Apply_Compile_Time_Constraint_Error
1419 (Expr, "value not in range of}?", CE_Range_Check_Failed,
1424 -- Start of processing for Apply_Scalar_Range_Check
1427 if Inside_A_Generic then
1430 -- Return if check obviously not needed. Note that we do not check
1431 -- for the expander being inactive, since this routine does not
1432 -- insert any code, but it does generate useful warnings sometimes,
1433 -- which we would like even if we are in semantics only mode.
1435 elsif Target_Typ = Any_Type
1436 or else not Is_Scalar_Type (Target_Typ)
1437 or else Raises_Constraint_Error (Expr)
1442 -- Now, see if checks are suppressed
1445 Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component;
1447 if Is_Subscr_Ref then
1448 Arr := Prefix (Parnt);
1449 Arr_Typ := Get_Actual_Subtype_If_Available (Arr);
1452 if not Do_Range_Check (Expr) then
1454 -- Subscript reference. Check for Index_Checks suppressed
1456 if Is_Subscr_Ref then
1458 -- Check array type and its base type
1460 if Index_Checks_Suppressed (Arr_Typ)
1461 or else Index_Checks_Suppressed (Base_Type (Arr_Typ))
1465 -- Check array itself if it is an entity name
1467 elsif Is_Entity_Name (Arr)
1468 and then Index_Checks_Suppressed (Entity (Arr))
1472 -- Check expression itself if it is an entity name
1474 elsif Is_Entity_Name (Expr)
1475 and then Index_Checks_Suppressed (Entity (Expr))
1480 -- All other cases, check for Range_Checks suppressed
1483 -- Check target type and its base type
1485 if Range_Checks_Suppressed (Target_Typ)
1486 or else Range_Checks_Suppressed (Base_Type (Target_Typ))
1490 -- Check expression itself if it is an entity name
1492 elsif Is_Entity_Name (Expr)
1493 and then Range_Checks_Suppressed (Entity (Expr))
1497 -- If Expr is part of an assignment statement, then check
1498 -- left side of assignment if it is an entity name.
1500 elsif Nkind (Parnt) = N_Assignment_Statement
1501 and then Is_Entity_Name (Name (Parnt))
1502 and then Range_Checks_Suppressed (Entity (Name (Parnt)))
1509 -- Do not set range checks if they are killed
1511 if Nkind (Expr) = N_Unchecked_Type_Conversion
1512 and then Kill_Range_Check (Expr)
1517 -- Do not set range checks for any values from System.Scalar_Values
1518 -- since the whole idea of such values is to avoid checking them!
1520 if Is_Entity_Name (Expr)
1521 and then Is_RTU (Scope (Entity (Expr)), System_Scalar_Values)
1526 -- Now see if we need a check
1528 if No (Source_Typ) then
1529 S_Typ := Etype (Expr);
1531 S_Typ := Source_Typ;
1534 if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then
1538 Is_Unconstrained_Subscr_Ref :=
1539 Is_Subscr_Ref and then not Is_Constrained (Arr_Typ);
1541 -- Always do a range check if the source type includes infinities
1542 -- and the target type does not include infinities. We do not do
1543 -- this if range checks are killed.
1545 if Is_Floating_Point_Type (S_Typ)
1546 and then Has_Infinities (S_Typ)
1547 and then not Has_Infinities (Target_Typ)
1549 Enable_Range_Check (Expr);
1552 -- Return if we know expression is definitely in the range of
1553 -- the target type as determined by Determine_Range. Right now
1554 -- we only do this for discrete types, and not fixed-point or
1555 -- floating-point types.
1557 -- The additional less-precise tests below catch these cases.
1559 -- Note: skip this if we are given a source_typ, since the point
1560 -- of supplying a Source_Typ is to stop us looking at the expression.
1561 -- could sharpen this test to be out parameters only ???
1563 if Is_Discrete_Type (Target_Typ)
1564 and then Is_Discrete_Type (Etype (Expr))
1565 and then not Is_Unconstrained_Subscr_Ref
1566 and then No (Source_Typ)
1569 Tlo : constant Node_Id := Type_Low_Bound (Target_Typ);
1570 Thi : constant Node_Id := Type_High_Bound (Target_Typ);
1575 if Compile_Time_Known_Value (Tlo)
1576 and then Compile_Time_Known_Value (Thi)
1579 Lov : constant Uint := Expr_Value (Tlo);
1580 Hiv : constant Uint := Expr_Value (Thi);
1583 -- If range is null, we for sure have a constraint error
1584 -- (we don't even need to look at the value involved,
1585 -- since all possible values will raise CE).
1592 -- Otherwise determine range of value
1594 Determine_Range (Expr, OK, Lo, Hi);
1598 -- If definitely in range, all OK
1600 if Lo >= Lov and then Hi <= Hiv then
1603 -- If definitely not in range, warn
1605 elsif Lov > Hi or else Hiv < Lo then
1609 -- Otherwise we don't know
1621 Is_Floating_Point_Type (S_Typ)
1622 or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int);
1624 -- Check if we can determine at compile time whether Expr is in the
1625 -- range of the target type. Note that if S_Typ is within the bounds
1626 -- of Target_Typ then this must be the case. This check is meaningful
1627 -- only if this is not a conversion between integer and real types.
1629 if not Is_Unconstrained_Subscr_Ref
1631 Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ)
1633 (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int)
1635 Is_In_Range (Expr, Target_Typ, Fixed_Int, Int_Real))
1639 elsif Is_Out_Of_Range (Expr, Target_Typ, Fixed_Int, Int_Real) then
1643 -- In the floating-point case, we only do range checks if the
1644 -- type is constrained. We definitely do NOT want range checks
1645 -- for unconstrained types, since we want to have infinities
1647 elsif Is_Floating_Point_Type (S_Typ) then
1648 if Is_Constrained (S_Typ) then
1649 Enable_Range_Check (Expr);
1652 -- For all other cases we enable a range check unconditionally
1655 Enable_Range_Check (Expr);
1658 end Apply_Scalar_Range_Check;
1660 ----------------------------------
1661 -- Apply_Selected_Length_Checks --
1662 ----------------------------------
1664 procedure Apply_Selected_Length_Checks
1666 Target_Typ : Entity_Id;
1667 Source_Typ : Entity_Id;
1668 Do_Static : Boolean)
1671 R_Result : Check_Result;
1674 Loc : constant Source_Ptr := Sloc (Ck_Node);
1675 Checks_On : constant Boolean :=
1676 (not Index_Checks_Suppressed (Target_Typ))
1678 (not Length_Checks_Suppressed (Target_Typ));
1681 if not Expander_Active then
1686 Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty);
1688 for J in 1 .. 2 loop
1689 R_Cno := R_Result (J);
1690 exit when No (R_Cno);
1692 -- A length check may mention an Itype which is attached to a
1693 -- subsequent node. At the top level in a package this can cause
1694 -- an order-of-elaboration problem, so we make sure that the itype
1695 -- is referenced now.
1697 if Ekind (Current_Scope) = E_Package
1698 and then Is_Compilation_Unit (Current_Scope)
1700 Ensure_Defined (Target_Typ, Ck_Node);
1702 if Present (Source_Typ) then
1703 Ensure_Defined (Source_Typ, Ck_Node);
1705 elsif Is_Itype (Etype (Ck_Node)) then
1706 Ensure_Defined (Etype (Ck_Node), Ck_Node);
1710 -- If the item is a conditional raise of constraint error,
1711 -- then have a look at what check is being performed and
1714 if Nkind (R_Cno) = N_Raise_Constraint_Error
1715 and then Present (Condition (R_Cno))
1717 Cond := Condition (R_Cno);
1719 if not Has_Dynamic_Length_Check (Ck_Node)
1722 Insert_Action (Ck_Node, R_Cno);
1724 if not Do_Static then
1725 Set_Has_Dynamic_Length_Check (Ck_Node);
1729 -- Output a warning if the condition is known to be True
1731 if Is_Entity_Name (Cond)
1732 and then Entity (Cond) = Standard_True
1734 Apply_Compile_Time_Constraint_Error
1735 (Ck_Node, "wrong length for array of}?",
1736 CE_Length_Check_Failed,
1740 -- If we were only doing a static check, or if checks are not
1741 -- on, then we want to delete the check, since it is not needed.
1742 -- We do this by replacing the if statement by a null statement
1744 elsif Do_Static or else not Checks_On then
1745 Rewrite (R_Cno, Make_Null_Statement (Loc));
1749 Install_Static_Check (R_Cno, Loc);
1754 end Apply_Selected_Length_Checks;
1756 ---------------------------------
1757 -- Apply_Selected_Range_Checks --
1758 ---------------------------------
1760 procedure Apply_Selected_Range_Checks
1762 Target_Typ : Entity_Id;
1763 Source_Typ : Entity_Id;
1764 Do_Static : Boolean)
1767 R_Result : Check_Result;
1770 Loc : constant Source_Ptr := Sloc (Ck_Node);
1771 Checks_On : constant Boolean :=
1772 (not Index_Checks_Suppressed (Target_Typ))
1774 (not Range_Checks_Suppressed (Target_Typ));
1777 if not Expander_Active or else not Checks_On then
1782 Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty);
1784 for J in 1 .. 2 loop
1786 R_Cno := R_Result (J);
1787 exit when No (R_Cno);
1789 -- If the item is a conditional raise of constraint error,
1790 -- then have a look at what check is being performed and
1793 if Nkind (R_Cno) = N_Raise_Constraint_Error
1794 and then Present (Condition (R_Cno))
1796 Cond := Condition (R_Cno);
1798 if not Has_Dynamic_Range_Check (Ck_Node) then
1799 Insert_Action (Ck_Node, R_Cno);
1801 if not Do_Static then
1802 Set_Has_Dynamic_Range_Check (Ck_Node);
1806 -- Output a warning if the condition is known to be True
1808 if Is_Entity_Name (Cond)
1809 and then Entity (Cond) = Standard_True
1811 -- Since an N_Range is technically not an expression, we
1812 -- have to set one of the bounds to C_E and then just flag
1813 -- the N_Range. The warning message will point to the
1814 -- lower bound and complain about a range, which seems OK.
1816 if Nkind (Ck_Node) = N_Range then
1817 Apply_Compile_Time_Constraint_Error
1818 (Low_Bound (Ck_Node), "static range out of bounds of}?",
1819 CE_Range_Check_Failed,
1823 Set_Raises_Constraint_Error (Ck_Node);
1826 Apply_Compile_Time_Constraint_Error
1827 (Ck_Node, "static value out of range of}?",
1828 CE_Range_Check_Failed,
1833 -- If we were only doing a static check, or if checks are not
1834 -- on, then we want to delete the check, since it is not needed.
1835 -- We do this by replacing the if statement by a null statement
1837 elsif Do_Static or else not Checks_On then
1838 Rewrite (R_Cno, Make_Null_Statement (Loc));
1842 Install_Static_Check (R_Cno, Loc);
1845 end Apply_Selected_Range_Checks;
1847 -------------------------------
1848 -- Apply_Static_Length_Check --
1849 -------------------------------
1851 procedure Apply_Static_Length_Check
1853 Target_Typ : Entity_Id;
1854 Source_Typ : Entity_Id := Empty)
1857 Apply_Selected_Length_Checks
1858 (Expr, Target_Typ, Source_Typ, Do_Static => True);
1859 end Apply_Static_Length_Check;
1861 -------------------------------------
1862 -- Apply_Subscript_Validity_Checks --
1863 -------------------------------------
1865 procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is
1869 pragma Assert (Nkind (Expr) = N_Indexed_Component);
1871 -- Loop through subscripts
1873 Sub := First (Expressions (Expr));
1874 while Present (Sub) loop
1876 -- Check one subscript. Note that we do not worry about
1877 -- enumeration type with holes, since we will convert the
1878 -- value to a Pos value for the subscript, and that convert
1879 -- will do the necessary validity check.
1881 Ensure_Valid (Sub, Holes_OK => True);
1883 -- Move to next subscript
1887 end Apply_Subscript_Validity_Checks;
1889 ----------------------------------
1890 -- Apply_Type_Conversion_Checks --
1891 ----------------------------------
1893 procedure Apply_Type_Conversion_Checks (N : Node_Id) is
1894 Target_Type : constant Entity_Id := Etype (N);
1895 Target_Base : constant Entity_Id := Base_Type (Target_Type);
1896 Expr : constant Node_Id := Expression (N);
1897 Expr_Type : constant Entity_Id := Etype (Expr);
1900 if Inside_A_Generic then
1903 -- Skip these checks if serious errors detected, there are some nasty
1904 -- situations of incomplete trees that blow things up.
1906 elsif Serious_Errors_Detected > 0 then
1909 -- Scalar type conversions of the form Target_Type (Expr) require
1910 -- a range check if we cannot be sure that Expr is in the base type
1911 -- of Target_Typ and also that Expr is in the range of Target_Typ.
1912 -- These are not quite the same condition from an implementation
1913 -- point of view, but clearly the second includes the first.
1915 elsif Is_Scalar_Type (Target_Type) then
1917 Conv_OK : constant Boolean := Conversion_OK (N);
1918 -- If the Conversion_OK flag on the type conversion is set
1919 -- and no floating point type is involved in the type conversion
1920 -- then fixed point values must be read as integral values.
1923 if not Overflow_Checks_Suppressed (Target_Base)
1924 and then not In_Subrange_Of (Expr_Type, Target_Base, Conv_OK)
1926 Set_Do_Overflow_Check (N);
1929 if not Range_Checks_Suppressed (Target_Type)
1930 and then not Range_Checks_Suppressed (Expr_Type)
1932 Apply_Scalar_Range_Check
1933 (Expr, Target_Type, Fixed_Int => Conv_OK);
1937 elsif Comes_From_Source (N)
1938 and then Is_Record_Type (Target_Type)
1939 and then Is_Derived_Type (Target_Type)
1940 and then not Is_Tagged_Type (Target_Type)
1941 and then not Is_Constrained (Target_Type)
1942 and then Present (Stored_Constraint (Target_Type))
1944 -- An unconstrained derived type may have inherited discriminant
1945 -- Build an actual discriminant constraint list using the stored
1946 -- constraint, to verify that the expression of the parent type
1947 -- satisfies the constraints imposed by the (unconstrained!)
1948 -- derived type. This applies to value conversions, not to view
1949 -- conversions of tagged types.
1952 Loc : constant Source_Ptr := Sloc (N);
1954 Constraint : Elmt_Id;
1955 Discr_Value : Node_Id;
1958 New_Constraints : constant Elist_Id := New_Elmt_List;
1959 Old_Constraints : constant Elist_Id :=
1960 Discriminant_Constraint (Expr_Type);
1963 Constraint := First_Elmt (Stored_Constraint (Target_Type));
1965 while Present (Constraint) loop
1966 Discr_Value := Node (Constraint);
1968 if Is_Entity_Name (Discr_Value)
1969 and then Ekind (Entity (Discr_Value)) = E_Discriminant
1971 Discr := Corresponding_Discriminant (Entity (Discr_Value));
1974 and then Scope (Discr) = Base_Type (Expr_Type)
1976 -- Parent is constrained by new discriminant. Obtain
1977 -- Value of original discriminant in expression. If
1978 -- the new discriminant has been used to constrain more
1979 -- than one of the stored discriminants, this will
1980 -- provide the required consistency check.
1983 Make_Selected_Component (Loc,
1985 Duplicate_Subexpr_No_Checks
1986 (Expr, Name_Req => True),
1988 Make_Identifier (Loc, Chars (Discr))),
1992 -- Discriminant of more remote ancestor ???
1997 -- Derived type definition has an explicit value for
1998 -- this stored discriminant.
2002 (Duplicate_Subexpr_No_Checks (Discr_Value),
2006 Next_Elmt (Constraint);
2009 -- Use the unconstrained expression type to retrieve the
2010 -- discriminants of the parent, and apply momentarily the
2011 -- discriminant constraint synthesized above.
2013 Set_Discriminant_Constraint (Expr_Type, New_Constraints);
2014 Cond := Build_Discriminant_Checks (Expr, Expr_Type);
2015 Set_Discriminant_Constraint (Expr_Type, Old_Constraints);
2018 Make_Raise_Constraint_Error (Loc,
2020 Reason => CE_Discriminant_Check_Failed));
2023 -- For arrays, conversions are applied during expansion, to take
2024 -- into accounts changes of representation. The checks become range
2025 -- checks on the base type or length checks on the subtype, depending
2026 -- on whether the target type is unconstrained or constrained.
2031 end Apply_Type_Conversion_Checks;
2033 ----------------------------------------------
2034 -- Apply_Universal_Integer_Attribute_Checks --
2035 ----------------------------------------------
2037 procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is
2038 Loc : constant Source_Ptr := Sloc (N);
2039 Typ : constant Entity_Id := Etype (N);
2042 if Inside_A_Generic then
2045 -- Nothing to do if checks are suppressed
2047 elsif Range_Checks_Suppressed (Typ)
2048 and then Overflow_Checks_Suppressed (Typ)
2052 -- Nothing to do if the attribute does not come from source. The
2053 -- internal attributes we generate of this type do not need checks,
2054 -- and furthermore the attempt to check them causes some circular
2055 -- elaboration orders when dealing with packed types.
2057 elsif not Comes_From_Source (N) then
2060 -- If the prefix is a selected component that depends on a discriminant
2061 -- the check may improperly expose a discriminant instead of using
2062 -- the bounds of the object itself. Set the type of the attribute to
2063 -- the base type of the context, so that a check will be imposed when
2064 -- needed (e.g. if the node appears as an index).
2066 elsif Nkind (Prefix (N)) = N_Selected_Component
2067 and then Ekind (Typ) = E_Signed_Integer_Subtype
2068 and then Depends_On_Discriminant (Scalar_Range (Typ))
2070 Set_Etype (N, Base_Type (Typ));
2072 -- Otherwise, replace the attribute node with a type conversion
2073 -- node whose expression is the attribute, retyped to universal
2074 -- integer, and whose subtype mark is the target type. The call
2075 -- to analyze this conversion will set range and overflow checks
2076 -- as required for proper detection of an out of range value.
2079 Set_Etype (N, Universal_Integer);
2080 Set_Analyzed (N, True);
2083 Make_Type_Conversion (Loc,
2084 Subtype_Mark => New_Occurrence_Of (Typ, Loc),
2085 Expression => Relocate_Node (N)));
2087 Analyze_And_Resolve (N, Typ);
2091 end Apply_Universal_Integer_Attribute_Checks;
2093 -------------------------------
2094 -- Build_Discriminant_Checks --
2095 -------------------------------
2097 function Build_Discriminant_Checks
2102 Loc : constant Source_Ptr := Sloc (N);
2105 Disc_Ent : Entity_Id;
2111 Disc := First_Elmt (Discriminant_Constraint (T_Typ));
2113 -- For a fully private type, use the discriminants of the parent type
2115 if Is_Private_Type (T_Typ)
2116 and then No (Full_View (T_Typ))
2118 Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ)));
2120 Disc_Ent := First_Discriminant (T_Typ);
2123 while Present (Disc) loop
2124 Dval := Node (Disc);
2126 if Nkind (Dval) = N_Identifier
2127 and then Ekind (Entity (Dval)) = E_Discriminant
2129 Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc);
2131 Dval := Duplicate_Subexpr_No_Checks (Dval);
2135 Make_Selected_Component (Loc,
2137 Duplicate_Subexpr_No_Checks (N, Name_Req => True),
2139 Make_Identifier (Loc, Chars (Disc_Ent)));
2141 Set_Is_In_Discriminant_Check (Dref);
2143 Evolve_Or_Else (Cond,
2146 Right_Opnd => Dval));
2149 Next_Discriminant (Disc_Ent);
2153 end Build_Discriminant_Checks;
2155 -----------------------------------
2156 -- Check_Valid_Lvalue_Subscripts --
2157 -----------------------------------
2159 procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is
2161 -- Skip this if range checks are suppressed
2163 if Range_Checks_Suppressed (Etype (Expr)) then
2166 -- Only do this check for expressions that come from source. We
2167 -- assume that expander generated assignments explicitly include
2168 -- any necessary checks. Note that this is not just an optimization,
2169 -- it avoids infinite recursions!
2171 elsif not Comes_From_Source (Expr) then
2174 -- For a selected component, check the prefix
2176 elsif Nkind (Expr) = N_Selected_Component then
2177 Check_Valid_Lvalue_Subscripts (Prefix (Expr));
2180 -- Case of indexed component
2182 elsif Nkind (Expr) = N_Indexed_Component then
2183 Apply_Subscript_Validity_Checks (Expr);
2185 -- Prefix may itself be or contain an indexed component, and
2186 -- these subscripts need checking as well
2188 Check_Valid_Lvalue_Subscripts (Prefix (Expr));
2190 end Check_Valid_Lvalue_Subscripts;
2192 ----------------------------------
2193 -- Conditional_Statements_Begin --
2194 ----------------------------------
2196 procedure Conditional_Statements_Begin is
2198 Saved_Checks_TOS := Saved_Checks_TOS + 1;
2200 -- If stack overflows, kill all checks, that way we know to
2201 -- simply reset the number of saved checks to zero on return.
2202 -- This should never occur in practice.
2204 if Saved_Checks_TOS > Saved_Checks_Stack'Last then
2207 -- In the normal case, we just make a new stack entry saving
2208 -- the current number of saved checks for a later restore.
2211 Saved_Checks_Stack (Saved_Checks_TOS) := Num_Saved_Checks;
2213 if Debug_Flag_CC then
2214 w ("Conditional_Statements_Begin: Num_Saved_Checks = ",
2218 end Conditional_Statements_Begin;
2220 --------------------------------
2221 -- Conditional_Statements_End --
2222 --------------------------------
2224 procedure Conditional_Statements_End is
2226 pragma Assert (Saved_Checks_TOS > 0);
2228 -- If the saved checks stack overflowed, then we killed all
2229 -- checks, so setting the number of saved checks back to
2230 -- zero is correct. This should never occur in practice.
2232 if Saved_Checks_TOS > Saved_Checks_Stack'Last then
2233 Num_Saved_Checks := 0;
2235 -- In the normal case, restore the number of saved checks
2236 -- from the top stack entry.
2239 Num_Saved_Checks := Saved_Checks_Stack (Saved_Checks_TOS);
2240 if Debug_Flag_CC then
2241 w ("Conditional_Statements_End: Num_Saved_Checks = ",
2246 Saved_Checks_TOS := Saved_Checks_TOS - 1;
2247 end Conditional_Statements_End;
2249 ---------------------
2250 -- Determine_Range --
2251 ---------------------
2253 Cache_Size : constant := 2 ** 10;
2254 type Cache_Index is range 0 .. Cache_Size - 1;
2255 -- Determine size of below cache (power of 2 is more efficient!)
2257 Determine_Range_Cache_N : array (Cache_Index) of Node_Id;
2258 Determine_Range_Cache_Lo : array (Cache_Index) of Uint;
2259 Determine_Range_Cache_Hi : array (Cache_Index) of Uint;
2260 -- The above arrays are used to implement a small direct cache
2261 -- for Determine_Range calls. Because of the way Determine_Range
2262 -- recursively traces subexpressions, and because overflow checking
2263 -- calls the routine on the way up the tree, a quadratic behavior
2264 -- can otherwise be encountered in large expressions. The cache
2265 -- entry for node N is stored in the (N mod Cache_Size) entry, and
2266 -- can be validated by checking the actual node value stored there.
2268 procedure Determine_Range
2274 Typ : constant Entity_Id := Etype (N);
2278 -- Lo and Hi bounds of left operand
2282 -- Lo and Hi bounds of right (or only) operand
2285 -- Temp variable used to hold a bound node
2288 -- High bound of base type of expression
2292 -- Refined values for low and high bounds, after tightening
2295 -- Used in lower level calls to indicate if call succeeded
2297 Cindex : Cache_Index;
2298 -- Used to search cache
2300 function OK_Operands return Boolean;
2301 -- Used for binary operators. Determines the ranges of the left and
2302 -- right operands, and if they are both OK, returns True, and puts
2303 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left
2309 function OK_Operands return Boolean is
2311 Determine_Range (Left_Opnd (N), OK1, Lo_Left, Hi_Left);
2317 Determine_Range (Right_Opnd (N), OK1, Lo_Right, Hi_Right);
2321 -- Start of processing for Determine_Range
2324 -- Prevent junk warnings by initializing range variables
2331 -- If the type is not discrete, or is undefined, then we can't
2332 -- do anything about determining the range.
2334 if No (Typ) or else not Is_Discrete_Type (Typ)
2335 or else Error_Posted (N)
2341 -- For all other cases, we can determine the range
2345 -- If value is compile time known, then the possible range is the
2346 -- one value that we know this expression definitely has!
2348 if Compile_Time_Known_Value (N) then
2349 Lo := Expr_Value (N);
2354 -- Return if already in the cache
2356 Cindex := Cache_Index (N mod Cache_Size);
2358 if Determine_Range_Cache_N (Cindex) = N then
2359 Lo := Determine_Range_Cache_Lo (Cindex);
2360 Hi := Determine_Range_Cache_Hi (Cindex);
2364 -- Otherwise, start by finding the bounds of the type of the
2365 -- expression, the value cannot be outside this range (if it
2366 -- is, then we have an overflow situation, which is a separate
2367 -- check, we are talking here only about the expression value).
2369 -- We use the actual bound unless it is dynamic, in which case
2370 -- use the corresponding base type bound if possible. If we can't
2371 -- get a bound then we figure we can't determine the range (a
2372 -- peculiar case, that perhaps cannot happen, but there is no
2373 -- point in bombing in this optimization circuit.
2375 -- First the low bound
2377 Bound := Type_Low_Bound (Typ);
2379 if Compile_Time_Known_Value (Bound) then
2380 Lo := Expr_Value (Bound);
2382 elsif Compile_Time_Known_Value (Type_Low_Bound (Base_Type (Typ))) then
2383 Lo := Expr_Value (Type_Low_Bound (Base_Type (Typ)));
2390 -- Now the high bound
2392 Bound := Type_High_Bound (Typ);
2394 -- We need the high bound of the base type later on, and this should
2395 -- always be compile time known. Again, it is not clear that this
2396 -- can ever be false, but no point in bombing.
2398 if Compile_Time_Known_Value (Type_High_Bound (Base_Type (Typ))) then
2399 Hbound := Expr_Value (Type_High_Bound (Base_Type (Typ)));
2407 -- If we have a static subtype, then that may have a tighter bound
2408 -- so use the upper bound of the subtype instead in this case.
2410 if Compile_Time_Known_Value (Bound) then
2411 Hi := Expr_Value (Bound);
2414 -- We may be able to refine this value in certain situations. If
2415 -- refinement is possible, then Lor and Hir are set to possibly
2416 -- tighter bounds, and OK1 is set to True.
2420 -- For unary plus, result is limited by range of operand
2423 Determine_Range (Right_Opnd (N), OK1, Lor, Hir);
2425 -- For unary minus, determine range of operand, and negate it
2428 Determine_Range (Right_Opnd (N), OK1, Lo_Right, Hi_Right);
2435 -- For binary addition, get range of each operand and do the
2436 -- addition to get the result range.
2440 Lor := Lo_Left + Lo_Right;
2441 Hir := Hi_Left + Hi_Right;
2444 -- Division is tricky. The only case we consider is where the
2445 -- right operand is a positive constant, and in this case we
2446 -- simply divide the bounds of the left operand
2450 if Lo_Right = Hi_Right
2451 and then Lo_Right > 0
2453 Lor := Lo_Left / Lo_Right;
2454 Hir := Hi_Left / Lo_Right;
2461 -- For binary subtraction, get range of each operand and do
2462 -- the worst case subtraction to get the result range.
2464 when N_Op_Subtract =>
2466 Lor := Lo_Left - Hi_Right;
2467 Hir := Hi_Left - Lo_Right;
2470 -- For MOD, if right operand is a positive constant, then
2471 -- result must be in the allowable range of mod results.
2475 if Lo_Right = Hi_Right
2476 and then Lo_Right /= 0
2478 if Lo_Right > 0 then
2480 Hir := Lo_Right - 1;
2482 else -- Lo_Right < 0
2483 Lor := Lo_Right + 1;
2492 -- For REM, if right operand is a positive constant, then
2493 -- result must be in the allowable range of mod results.
2497 if Lo_Right = Hi_Right
2498 and then Lo_Right /= 0
2501 Dval : constant Uint := (abs Lo_Right) - 1;
2504 -- The sign of the result depends on the sign of the
2505 -- dividend (but not on the sign of the divisor, hence
2506 -- the abs operation above).
2526 -- Attribute reference cases
2528 when N_Attribute_Reference =>
2529 case Attribute_Name (N) is
2531 -- For Pos/Val attributes, we can refine the range using the
2532 -- possible range of values of the attribute expression
2534 when Name_Pos | Name_Val =>
2535 Determine_Range (First (Expressions (N)), OK1, Lor, Hir);
2537 -- For Length attribute, use the bounds of the corresponding
2538 -- index type to refine the range.
2542 Atyp : Entity_Id := Etype (Prefix (N));
2550 if Is_Access_Type (Atyp) then
2551 Atyp := Designated_Type (Atyp);
2554 -- For string literal, we know exact value
2556 if Ekind (Atyp) = E_String_Literal_Subtype then
2558 Lo := String_Literal_Length (Atyp);
2559 Hi := String_Literal_Length (Atyp);
2563 -- Otherwise check for expression given
2565 if No (Expressions (N)) then
2569 UI_To_Int (Expr_Value (First (Expressions (N))));
2572 Indx := First_Index (Atyp);
2573 for J in 2 .. Inum loop
2574 Indx := Next_Index (Indx);
2578 (Type_Low_Bound (Etype (Indx)), OK1, LL, LU);
2582 (Type_High_Bound (Etype (Indx)), OK1, UL, UU);
2586 -- The maximum value for Length is the biggest
2587 -- possible gap between the values of the bounds.
2588 -- But of course, this value cannot be negative.
2590 Hir := UI_Max (Uint_0, UU - LL);
2592 -- For constrained arrays, the minimum value for
2593 -- Length is taken from the actual value of the
2594 -- bounds, since the index will be exactly of
2597 if Is_Constrained (Atyp) then
2598 Lor := UI_Max (Uint_0, UL - LU);
2600 -- For an unconstrained array, the minimum value
2601 -- for length is always zero.
2610 -- No special handling for other attributes
2611 -- Probably more opportunities exist here ???
2618 -- For type conversion from one discrete type to another, we
2619 -- can refine the range using the converted value.
2621 when N_Type_Conversion =>
2622 Determine_Range (Expression (N), OK1, Lor, Hir);
2624 -- Nothing special to do for all other expression kinds
2632 -- At this stage, if OK1 is true, then we know that the actual
2633 -- result of the computed expression is in the range Lor .. Hir.
2634 -- We can use this to restrict the possible range of results.
2638 -- If the refined value of the low bound is greater than the
2639 -- type high bound, then reset it to the more restrictive
2640 -- value. However, we do NOT do this for the case of a modular
2641 -- type where the possible upper bound on the value is above the
2642 -- base type high bound, because that means the result could wrap.
2645 and then not (Is_Modular_Integer_Type (Typ)
2646 and then Hir > Hbound)
2651 -- Similarly, if the refined value of the high bound is less
2652 -- than the value so far, then reset it to the more restrictive
2653 -- value. Again, we do not do this if the refined low bound is
2654 -- negative for a modular type, since this would wrap.
2657 and then not (Is_Modular_Integer_Type (Typ)
2658 and then Lor < Uint_0)
2664 -- Set cache entry for future call and we are all done
2666 Determine_Range_Cache_N (Cindex) := N;
2667 Determine_Range_Cache_Lo (Cindex) := Lo;
2668 Determine_Range_Cache_Hi (Cindex) := Hi;
2671 -- If any exception occurs, it means that we have some bug in the compiler
2672 -- possibly triggered by a previous error, or by some unforseen peculiar
2673 -- occurrence. However, this is only an optimization attempt, so there is
2674 -- really no point in crashing the compiler. Instead we just decide, too
2675 -- bad, we can't figure out a range in this case after all.
2680 -- Debug flag K disables this behavior (useful for debugging)
2682 if Debug_Flag_K then
2690 end Determine_Range;
2692 ------------------------------------
2693 -- Discriminant_Checks_Suppressed --
2694 ------------------------------------
2696 function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is
2699 if Is_Unchecked_Union (E) then
2701 elsif Checks_May_Be_Suppressed (E) then
2702 return Is_Check_Suppressed (E, Discriminant_Check);
2706 return Scope_Suppress (Discriminant_Check);
2707 end Discriminant_Checks_Suppressed;
2709 --------------------------------
2710 -- Division_Checks_Suppressed --
2711 --------------------------------
2713 function Division_Checks_Suppressed (E : Entity_Id) return Boolean is
2715 if Present (E) and then Checks_May_Be_Suppressed (E) then
2716 return Is_Check_Suppressed (E, Division_Check);
2718 return Scope_Suppress (Division_Check);
2720 end Division_Checks_Suppressed;
2722 -----------------------------------
2723 -- Elaboration_Checks_Suppressed --
2724 -----------------------------------
2726 function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is
2729 if Kill_Elaboration_Checks (E) then
2731 elsif Checks_May_Be_Suppressed (E) then
2732 return Is_Check_Suppressed (E, Elaboration_Check);
2736 return Scope_Suppress (Elaboration_Check);
2737 end Elaboration_Checks_Suppressed;
2739 ---------------------------
2740 -- Enable_Overflow_Check --
2741 ---------------------------
2743 procedure Enable_Overflow_Check (N : Node_Id) is
2744 Typ : constant Entity_Id := Base_Type (Etype (N));
2753 if Debug_Flag_CC then
2754 w ("Enable_Overflow_Check for node ", Int (N));
2755 Write_Str (" Source location = ");
2760 -- Nothing to do if the range of the result is known OK. We skip
2761 -- this for conversions, since the caller already did the check,
2762 -- and in any case the condition for deleting the check for a
2763 -- type conversion is different in any case.
2765 if Nkind (N) /= N_Type_Conversion then
2766 Determine_Range (N, OK, Lo, Hi);
2768 -- Note in the test below that we assume that if a bound of the
2769 -- range is equal to that of the type. That's not quite accurate
2770 -- but we do this for the following reasons:
2772 -- a) The way that Determine_Range works, it will typically report
2773 -- the bounds of the value as being equal to the bounds of the
2774 -- type, because it either can't tell anything more precise, or
2775 -- does not think it is worth the effort to be more precise.
2777 -- b) It is very unusual to have a situation in which this would
2778 -- generate an unnecessary overflow check (an example would be
2779 -- a subtype with a range 0 .. Integer'Last - 1 to which the
2780 -- literal value one is added.
2782 -- c) The alternative is a lot of special casing in this routine
2783 -- which would partially duplicate Determine_Range processing.
2786 and then Lo > Expr_Value (Type_Low_Bound (Typ))
2787 and then Hi < Expr_Value (Type_High_Bound (Typ))
2789 if Debug_Flag_CC then
2790 w ("No overflow check required");
2797 -- If not in optimizing mode, set flag and we are done. We are also
2798 -- done (and just set the flag) if the type is not a discrete type,
2799 -- since it is not worth the effort to eliminate checks for other
2800 -- than discrete types. In addition, we take this same path if we
2801 -- have stored the maximum number of checks possible already (a
2802 -- very unlikely situation, but we do not want to blow up!)
2804 if Optimization_Level = 0
2805 or else not Is_Discrete_Type (Etype (N))
2806 or else Num_Saved_Checks = Saved_Checks'Last
2808 Set_Do_Overflow_Check (N, True);
2810 if Debug_Flag_CC then
2811 w ("Optimization off");
2817 -- Otherwise evaluate and check the expression
2822 Target_Type => Empty,
2828 if Debug_Flag_CC then
2829 w ("Called Find_Check");
2833 w (" Check_Num = ", Chk);
2834 w (" Ent = ", Int (Ent));
2835 Write_Str (" Ofs = ");
2840 -- If check is not of form to optimize, then set flag and we are done
2843 Set_Do_Overflow_Check (N, True);
2847 -- If check is already performed, then return without setting flag
2850 if Debug_Flag_CC then
2851 w ("Check suppressed!");
2857 -- Here we will make a new entry for the new check
2859 Set_Do_Overflow_Check (N, True);
2860 Num_Saved_Checks := Num_Saved_Checks + 1;
2861 Saved_Checks (Num_Saved_Checks) :=
2866 Target_Type => Empty);
2868 if Debug_Flag_CC then
2869 w ("Make new entry, check number = ", Num_Saved_Checks);
2870 w (" Entity = ", Int (Ent));
2871 Write_Str (" Offset = ");
2873 w (" Check_Type = O");
2874 w (" Target_Type = Empty");
2877 -- If we get an exception, then something went wrong, probably because
2878 -- of an error in the structure of the tree due to an incorrect program.
2879 -- Or it may be a bug in the optimization circuit. In either case the
2880 -- safest thing is simply to set the check flag unconditionally.
2884 Set_Do_Overflow_Check (N, True);
2886 if Debug_Flag_CC then
2887 w (" exception occurred, overflow flag set");
2891 end Enable_Overflow_Check;
2893 ------------------------
2894 -- Enable_Range_Check --
2895 ------------------------
2897 procedure Enable_Range_Check (N : Node_Id) is
2906 -- Return if unchecked type conversion with range check killed.
2907 -- In this case we never set the flag (that's what Kill_Range_Check
2910 if Nkind (N) = N_Unchecked_Type_Conversion
2911 and then Kill_Range_Check (N)
2916 -- Debug trace output
2918 if Debug_Flag_CC then
2919 w ("Enable_Range_Check for node ", Int (N));
2920 Write_Str (" Source location = ");
2925 -- If not in optimizing mode, set flag and we are done. We are also
2926 -- done (and just set the flag) if the type is not a discrete type,
2927 -- since it is not worth the effort to eliminate checks for other
2928 -- than discrete types. In addition, we take this same path if we
2929 -- have stored the maximum number of checks possible already (a
2930 -- very unlikely situation, but we do not want to blow up!)
2932 if Optimization_Level = 0
2933 or else No (Etype (N))
2934 or else not Is_Discrete_Type (Etype (N))
2935 or else Num_Saved_Checks = Saved_Checks'Last
2937 Set_Do_Range_Check (N, True);
2939 if Debug_Flag_CC then
2940 w ("Optimization off");
2946 -- Otherwise find out the target type
2950 -- For assignment, use left side subtype
2952 if Nkind (P) = N_Assignment_Statement
2953 and then Expression (P) = N
2955 Ttyp := Etype (Name (P));
2957 -- For indexed component, use subscript subtype
2959 elsif Nkind (P) = N_Indexed_Component then
2966 Atyp := Etype (Prefix (P));
2968 if Is_Access_Type (Atyp) then
2969 Atyp := Designated_Type (Atyp);
2972 Indx := First_Index (Atyp);
2973 Subs := First (Expressions (P));
2976 Ttyp := Etype (Indx);
2985 -- For now, ignore all other cases, they are not so interesting
2988 if Debug_Flag_CC then
2989 w (" target type not found, flag set");
2992 Set_Do_Range_Check (N, True);
2996 -- Evaluate and check the expression
3001 Target_Type => Ttyp,
3007 if Debug_Flag_CC then
3008 w ("Called Find_Check");
3009 w ("Target_Typ = ", Int (Ttyp));
3013 w (" Check_Num = ", Chk);
3014 w (" Ent = ", Int (Ent));
3015 Write_Str (" Ofs = ");
3020 -- If check is not of form to optimize, then set flag and we are done
3023 if Debug_Flag_CC then
3024 w (" expression not of optimizable type, flag set");
3027 Set_Do_Range_Check (N, True);
3031 -- If check is already performed, then return without setting flag
3034 if Debug_Flag_CC then
3035 w ("Check suppressed!");
3041 -- Here we will make a new entry for the new check
3043 Set_Do_Range_Check (N, True);
3044 Num_Saved_Checks := Num_Saved_Checks + 1;
3045 Saved_Checks (Num_Saved_Checks) :=
3050 Target_Type => Ttyp);
3052 if Debug_Flag_CC then
3053 w ("Make new entry, check number = ", Num_Saved_Checks);
3054 w (" Entity = ", Int (Ent));
3055 Write_Str (" Offset = ");
3057 w (" Check_Type = R");
3058 w (" Target_Type = ", Int (Ttyp));
3062 -- If we get an exception, then something went wrong, probably because
3063 -- of an error in the structure of the tree due to an incorrect program.
3064 -- Or it may be a bug in the optimization circuit. In either case the
3065 -- safest thing is simply to set the check flag unconditionally.
3069 Set_Do_Range_Check (N, True);
3071 if Debug_Flag_CC then
3072 w (" exception occurred, range flag set");
3076 end Enable_Range_Check;
3082 procedure Ensure_Valid (Expr : Node_Id; Holes_OK : Boolean := False) is
3083 Typ : constant Entity_Id := Etype (Expr);
3086 -- Ignore call if we are not doing any validity checking
3088 if not Validity_Checks_On then
3091 -- Ignore call if range checks suppressed on entity in question
3093 elsif Is_Entity_Name (Expr)
3094 and then Range_Checks_Suppressed (Entity (Expr))
3098 -- No check required if expression is from the expander, we assume
3099 -- the expander will generate whatever checks are needed. Note that
3100 -- this is not just an optimization, it avoids infinite recursions!
3102 -- Unchecked conversions must be checked, unless they are initialized
3103 -- scalar values, as in a component assignment in an init proc.
3105 -- In addition, we force a check if Force_Validity_Checks is set
3107 elsif not Comes_From_Source (Expr)
3108 and then not Force_Validity_Checks
3109 and then (Nkind (Expr) /= N_Unchecked_Type_Conversion
3110 or else Kill_Range_Check (Expr))
3114 -- No check required if expression is known to have valid value
3116 elsif Expr_Known_Valid (Expr) then
3119 -- No check required if checks off
3121 elsif Range_Checks_Suppressed (Typ) then
3124 -- Ignore case of enumeration with holes where the flag is set not
3125 -- to worry about holes, since no special validity check is needed
3127 elsif Is_Enumeration_Type (Typ)
3128 and then Has_Non_Standard_Rep (Typ)
3133 -- No check required on the left-hand side of an assignment.
3135 elsif Nkind (Parent (Expr)) = N_Assignment_Statement
3136 and then Expr = Name (Parent (Expr))
3140 -- An annoying special case. If this is an out parameter of a scalar
3141 -- type, then the value is not going to be accessed, therefore it is
3142 -- inappropriate to do any validity check at the call site.
3145 -- Only need to worry about scalar types
3147 if Is_Scalar_Type (Typ) then
3157 -- Find actual argument (which may be a parameter association)
3158 -- and the parent of the actual argument (the call statement)
3163 if Nkind (P) = N_Parameter_Association then
3168 -- Only need to worry if we are argument of a procedure
3169 -- call since functions don't have out parameters. If this
3170 -- is an indirect or dispatching call, get signature from
3171 -- the subprogram type.
3173 if Nkind (P) = N_Procedure_Call_Statement then
3174 L := Parameter_Associations (P);
3176 if Is_Entity_Name (Name (P)) then
3177 E := Entity (Name (P));
3179 pragma Assert (Nkind (Name (P)) = N_Explicit_Dereference);
3180 E := Etype (Name (P));
3183 -- Only need to worry if there are indeed actuals, and
3184 -- if this could be a procedure call, otherwise we cannot
3185 -- get a match (either we are not an argument, or the
3186 -- mode of the formal is not OUT). This test also filters
3187 -- out the generic case.
3189 if Is_Non_Empty_List (L)
3190 and then Is_Subprogram (E)
3192 -- This is the loop through parameters, looking to
3193 -- see if there is an OUT parameter for which we are
3196 F := First_Formal (E);
3199 while Present (F) loop
3200 if Ekind (F) = E_Out_Parameter and then A = N then
3213 -- If we fall through, a validity check is required. Note that it would
3214 -- not be good to set Do_Range_Check, even in contexts where this is
3215 -- permissible, since this flag causes checking against the target type,
3216 -- not the source type in contexts such as assignments
3218 Insert_Valid_Check (Expr);
3221 ----------------------
3222 -- Expr_Known_Valid --
3223 ----------------------
3225 function Expr_Known_Valid (Expr : Node_Id) return Boolean is
3226 Typ : constant Entity_Id := Etype (Expr);
3229 -- Non-scalar types are always consdered valid, since they never
3230 -- give rise to the issues of erroneous or bounded error behavior
3231 -- that are the concern. In formal reference manual terms the
3232 -- notion of validity only applies to scalar types.
3234 if not Is_Scalar_Type (Typ) then
3237 -- If no validity checking, then everything is considered valid
3239 elsif not Validity_Checks_On then
3242 -- Floating-point types are considered valid unless floating-point
3243 -- validity checks have been specifically turned on.
3245 elsif Is_Floating_Point_Type (Typ)
3246 and then not Validity_Check_Floating_Point
3250 -- If the expression is the value of an object that is known to
3251 -- be valid, then clearly the expression value itself is valid.
3253 elsif Is_Entity_Name (Expr)
3254 and then Is_Known_Valid (Entity (Expr))
3258 -- If the type is one for which all values are known valid, then
3259 -- we are sure that the value is valid except in the slightly odd
3260 -- case where the expression is a reference to a variable whose size
3261 -- has been explicitly set to a value greater than the object size.
3263 elsif Is_Known_Valid (Typ) then
3264 if Is_Entity_Name (Expr)
3265 and then Ekind (Entity (Expr)) = E_Variable
3266 and then Esize (Entity (Expr)) > Esize (Typ)
3273 -- Integer and character literals always have valid values, where
3274 -- appropriate these will be range checked in any case.
3276 elsif Nkind (Expr) = N_Integer_Literal
3278 Nkind (Expr) = N_Character_Literal
3282 -- If we have a type conversion or a qualification of a known valid
3283 -- value, then the result will always be valid.
3285 elsif Nkind (Expr) = N_Type_Conversion
3287 Nkind (Expr) = N_Qualified_Expression
3289 return Expr_Known_Valid (Expression (Expr));
3291 -- The result of any function call or operator is always considered
3292 -- valid, since we assume the necessary checks are done by the call.
3294 elsif Nkind (Expr) in N_Binary_Op
3296 Nkind (Expr) in N_Unary_Op
3298 Nkind (Expr) = N_Function_Call
3302 -- For all other cases, we do not know the expression is valid
3307 end Expr_Known_Valid;
3313 procedure Find_Check
3315 Check_Type : Character;
3316 Target_Type : Entity_Id;
3317 Entry_OK : out Boolean;
3318 Check_Num : out Nat;
3319 Ent : out Entity_Id;
3322 function Within_Range_Of
3323 (Target_Type : Entity_Id;
3324 Check_Type : Entity_Id)
3326 -- Given a requirement for checking a range against Target_Type, and
3327 -- and a range Check_Type against which a check has already been made,
3328 -- determines if the check against check type is sufficient to ensure
3329 -- that no check against Target_Type is required.
3331 ---------------------
3332 -- Within_Range_Of --
3333 ---------------------
3335 function Within_Range_Of
3336 (Target_Type : Entity_Id;
3337 Check_Type : Entity_Id)
3341 if Target_Type = Check_Type then
3346 Tlo : constant Node_Id := Type_Low_Bound (Target_Type);
3347 Thi : constant Node_Id := Type_High_Bound (Target_Type);
3348 Clo : constant Node_Id := Type_Low_Bound (Check_Type);
3349 Chi : constant Node_Id := Type_High_Bound (Check_Type);
3353 or else (Compile_Time_Known_Value (Tlo)
3355 Compile_Time_Known_Value (Clo)
3357 Expr_Value (Clo) >= Expr_Value (Tlo)))
3360 or else (Compile_Time_Known_Value (Thi)
3362 Compile_Time_Known_Value (Chi)
3364 Expr_Value (Chi) <= Expr_Value (Clo)))
3372 end Within_Range_Of;
3374 -- Start of processing for Find_Check
3377 -- Establish default, to avoid warnings from GCC.
3381 -- Case of expression is simple entity reference
3383 if Is_Entity_Name (Expr) then
3384 Ent := Entity (Expr);
3387 -- Case of expression is entity + known constant
3389 elsif Nkind (Expr) = N_Op_Add
3390 and then Compile_Time_Known_Value (Right_Opnd (Expr))
3391 and then Is_Entity_Name (Left_Opnd (Expr))
3393 Ent := Entity (Left_Opnd (Expr));
3394 Ofs := Expr_Value (Right_Opnd (Expr));
3396 -- Case of expression is entity - known constant
3398 elsif Nkind (Expr) = N_Op_Subtract
3399 and then Compile_Time_Known_Value (Right_Opnd (Expr))
3400 and then Is_Entity_Name (Left_Opnd (Expr))
3402 Ent := Entity (Left_Opnd (Expr));
3403 Ofs := UI_Negate (Expr_Value (Right_Opnd (Expr)));
3405 -- Any other expression is not of the right form
3414 -- Come here with expression of appropriate form, check if
3415 -- entity is an appropriate one for our purposes.
3417 if (Ekind (Ent) = E_Variable
3419 Ekind (Ent) = E_Constant
3421 Ekind (Ent) = E_Loop_Parameter
3423 Ekind (Ent) = E_In_Parameter)
3424 and then not Is_Library_Level_Entity (Ent)
3432 -- See if there is matching check already
3434 for J in reverse 1 .. Num_Saved_Checks loop
3436 SC : Saved_Check renames Saved_Checks (J);
3439 if SC.Killed = False
3440 and then SC.Entity = Ent
3441 and then SC.Offset = Ofs
3442 and then SC.Check_Type = Check_Type
3443 and then Within_Range_Of (Target_Type, SC.Target_Type)
3451 -- If we fall through entry was not found
3457 ---------------------------------
3458 -- Generate_Discriminant_Check --
3459 ---------------------------------
3461 -- Note: the code for this procedure is derived from the
3462 -- emit_discriminant_check routine a-trans.c v1.659.
3464 procedure Generate_Discriminant_Check (N : Node_Id) is
3465 Loc : constant Source_Ptr := Sloc (N);
3466 Pref : constant Node_Id := Prefix (N);
3467 Sel : constant Node_Id := Selector_Name (N);
3469 Orig_Comp : constant Entity_Id :=
3470 Original_Record_Component (Entity (Sel));
3471 -- The original component to be checked
3473 Discr_Fct : constant Entity_Id :=
3474 Discriminant_Checking_Func (Orig_Comp);
3475 -- The discriminant checking function
3478 -- One discriminant to be checked in the type
3480 Real_Discr : Entity_Id;
3481 -- Actual discriminant in the call
3483 Pref_Type : Entity_Id;
3484 -- Type of relevant prefix (ignoring private/access stuff)
3487 -- List of arguments for function call
3490 -- Keep track of the formal corresponding to the actual we build
3491 -- for each discriminant, in order to be able to perform the
3492 -- necessary type conversions.
3495 -- Selected component reference for checking function argument
3498 Pref_Type := Etype (Pref);
3500 -- Force evaluation of the prefix, so that it does not get evaluated
3501 -- twice (once for the check, once for the actual reference). Such a
3502 -- double evaluation is always a potential source of inefficiency,
3503 -- and is functionally incorrect in the volatile case, or when the
3504 -- prefix may have side-effects. An entity or a component of an
3505 -- entity requires no evaluation.
3507 if Is_Entity_Name (Pref) then
3508 if Treat_As_Volatile (Entity (Pref)) then
3509 Force_Evaluation (Pref, Name_Req => True);
3512 elsif Treat_As_Volatile (Etype (Pref)) then
3513 Force_Evaluation (Pref, Name_Req => True);
3515 elsif Nkind (Pref) = N_Selected_Component
3516 and then Is_Entity_Name (Prefix (Pref))
3521 Force_Evaluation (Pref, Name_Req => True);
3524 -- For a tagged type, use the scope of the original component to
3525 -- obtain the type, because ???
3527 if Is_Tagged_Type (Scope (Orig_Comp)) then
3528 Pref_Type := Scope (Orig_Comp);
3530 -- For an untagged derived type, use the discriminants of the
3531 -- parent which have been renamed in the derivation, possibly
3532 -- by a one-to-many discriminant constraint.
3533 -- For non-tagged type, initially get the Etype of the prefix
3536 if Is_Derived_Type (Pref_Type)
3537 and then Number_Discriminants (Pref_Type) /=
3538 Number_Discriminants (Etype (Base_Type (Pref_Type)))
3540 Pref_Type := Etype (Base_Type (Pref_Type));
3544 -- We definitely should have a checking function, This routine should
3545 -- not be called if no discriminant checking function is present.
3547 pragma Assert (Present (Discr_Fct));
3549 -- Create the list of the actual parameters for the call. This list
3550 -- is the list of the discriminant fields of the record expression to
3551 -- be discriminant checked.
3554 Formal := First_Formal (Discr_Fct);
3555 Discr := First_Discriminant (Pref_Type);
3556 while Present (Discr) loop
3558 -- If we have a corresponding discriminant field, and a parent
3559 -- subtype is present, then we want to use the corresponding
3560 -- discriminant since this is the one with the useful value.
3562 if Present (Corresponding_Discriminant (Discr))
3563 and then Ekind (Pref_Type) = E_Record_Type
3564 and then Present (Parent_Subtype (Pref_Type))
3566 Real_Discr := Corresponding_Discriminant (Discr);
3568 Real_Discr := Discr;
3571 -- Construct the reference to the discriminant
3574 Make_Selected_Component (Loc,
3576 Unchecked_Convert_To (Pref_Type,
3577 Duplicate_Subexpr (Pref)),
3578 Selector_Name => New_Occurrence_Of (Real_Discr, Loc));
3580 -- Manually analyze and resolve this selected component. We really
3581 -- want it just as it appears above, and do not want the expander
3582 -- playing discriminal games etc with this reference. Then we
3583 -- append the argument to the list we are gathering.
3585 Set_Etype (Scomp, Etype (Real_Discr));
3586 Set_Analyzed (Scomp, True);
3587 Append_To (Args, Convert_To (Etype (Formal), Scomp));
3589 Next_Formal_With_Extras (Formal);
3590 Next_Discriminant (Discr);
3593 -- Now build and insert the call
3596 Make_Raise_Constraint_Error (Loc,
3598 Make_Function_Call (Loc,
3599 Name => New_Occurrence_Of (Discr_Fct, Loc),
3600 Parameter_Associations => Args),
3601 Reason => CE_Discriminant_Check_Failed));
3602 end Generate_Discriminant_Check;
3604 ----------------------------
3605 -- Generate_Index_Checks --
3606 ----------------------------
3608 procedure Generate_Index_Checks (N : Node_Id) is
3609 Loc : constant Source_Ptr := Sloc (N);
3610 A : constant Node_Id := Prefix (N);
3616 Sub := First (Expressions (N));
3618 while Present (Sub) loop
3619 if Do_Range_Check (Sub) then
3620 Set_Do_Range_Check (Sub, False);
3622 -- Force evaluation except for the case of a simple name of
3623 -- a non-volatile entity.
3625 if not Is_Entity_Name (Sub)
3626 or else Treat_As_Volatile (Entity (Sub))
3628 Force_Evaluation (Sub);
3631 -- Generate a raise of constraint error with the appropriate
3632 -- reason and a condition of the form:
3634 -- Base_Type(Sub) not in array'range (subscript)
3636 -- Note that the reason we generate the conversion to the
3637 -- base type here is that we definitely want the range check
3638 -- to take place, even if it looks like the subtype is OK.
3639 -- Optimization considerations that allow us to omit the
3640 -- check have already been taken into account in the setting
3641 -- of the Do_Range_Check flag earlier on.
3646 Num := New_List (Make_Integer_Literal (Loc, Ind));
3650 Make_Raise_Constraint_Error (Loc,
3654 Convert_To (Base_Type (Etype (Sub)),
3655 Duplicate_Subexpr_Move_Checks (Sub)),
3657 Make_Attribute_Reference (Loc,
3658 Prefix => Duplicate_Subexpr_Move_Checks (A),
3659 Attribute_Name => Name_Range,
3660 Expressions => Num)),
3661 Reason => CE_Index_Check_Failed));
3667 end Generate_Index_Checks;
3669 --------------------------
3670 -- Generate_Range_Check --
3671 --------------------------
3673 procedure Generate_Range_Check
3675 Target_Type : Entity_Id;
3676 Reason : RT_Exception_Code)
3678 Loc : constant Source_Ptr := Sloc (N);
3679 Source_Type : constant Entity_Id := Etype (N);
3680 Source_Base_Type : constant Entity_Id := Base_Type (Source_Type);
3681 Target_Base_Type : constant Entity_Id := Base_Type (Target_Type);
3684 -- First special case, if the source type is already within the
3685 -- range of the target type, then no check is needed (probably we
3686 -- should have stopped Do_Range_Check from being set in the first
3687 -- place, but better late than later in preventing junk code!
3689 -- We do NOT apply this if the source node is a literal, since in
3690 -- this case the literal has already been labeled as having the
3691 -- subtype of the target.
3693 if In_Subrange_Of (Source_Type, Target_Type)
3695 (Nkind (N) = N_Integer_Literal
3697 Nkind (N) = N_Real_Literal
3699 Nkind (N) = N_Character_Literal
3702 and then Ekind (Entity (N)) = E_Enumeration_Literal))
3707 -- We need a check, so force evaluation of the node, so that it does
3708 -- not get evaluated twice (once for the check, once for the actual
3709 -- reference). Such a double evaluation is always a potential source
3710 -- of inefficiency, and is functionally incorrect in the volatile case.
3712 if not Is_Entity_Name (N)
3713 or else Treat_As_Volatile (Entity (N))
3715 Force_Evaluation (N);
3718 -- The easiest case is when Source_Base_Type and Target_Base_Type
3719 -- are the same since in this case we can simply do a direct
3720 -- check of the value of N against the bounds of Target_Type.
3722 -- [constraint_error when N not in Target_Type]
3724 -- Note: this is by far the most common case, for example all cases of
3725 -- checks on the RHS of assignments are in this category, but not all
3726 -- cases are like this. Notably conversions can involve two types.
3728 if Source_Base_Type = Target_Base_Type then
3730 Make_Raise_Constraint_Error (Loc,
3733 Left_Opnd => Duplicate_Subexpr (N),
3734 Right_Opnd => New_Occurrence_Of (Target_Type, Loc)),
3737 -- Next test for the case where the target type is within the bounds
3738 -- of the base type of the source type, since in this case we can
3739 -- simply convert these bounds to the base type of T to do the test.
3741 -- [constraint_error when N not in
3742 -- Source_Base_Type (Target_Type'First)
3744 -- Source_Base_Type(Target_Type'Last))]
3746 -- The conversions will always work and need no check.
3748 elsif In_Subrange_Of (Target_Type, Source_Base_Type) then
3750 Make_Raise_Constraint_Error (Loc,
3753 Left_Opnd => Duplicate_Subexpr (N),
3758 Convert_To (Source_Base_Type,
3759 Make_Attribute_Reference (Loc,
3761 New_Occurrence_Of (Target_Type, Loc),
3762 Attribute_Name => Name_First)),
3765 Convert_To (Source_Base_Type,
3766 Make_Attribute_Reference (Loc,
3768 New_Occurrence_Of (Target_Type, Loc),
3769 Attribute_Name => Name_Last)))),
3772 -- Note that at this stage we now that the Target_Base_Type is
3773 -- not in the range of the Source_Base_Type (since even the
3774 -- Target_Type itself is not in this range). It could still be
3775 -- the case that the Source_Type is in range of the target base
3776 -- type, since we have not checked that case.
3778 -- If that is the case, we can freely convert the source to the
3779 -- target, and then test the target result against the bounds.
3781 elsif In_Subrange_Of (Source_Type, Target_Base_Type) then
3783 -- We make a temporary to hold the value of the converted
3784 -- value (converted to the base type), and then we will
3785 -- do the test against this temporary.
3787 -- Tnn : constant Target_Base_Type := Target_Base_Type (N);
3788 -- [constraint_error when Tnn not in Target_Type]
3790 -- Then the conversion itself is replaced by an occurrence of Tnn
3793 Tnn : constant Entity_Id :=
3794 Make_Defining_Identifier (Loc,
3795 Chars => New_Internal_Name ('T'));
3798 Insert_Actions (N, New_List (
3799 Make_Object_Declaration (Loc,
3800 Defining_Identifier => Tnn,
3801 Object_Definition =>
3802 New_Occurrence_Of (Target_Base_Type, Loc),
3803 Constant_Present => True,
3805 Make_Type_Conversion (Loc,
3806 Subtype_Mark => New_Occurrence_Of (Target_Base_Type, Loc),
3807 Expression => Duplicate_Subexpr (N))),
3809 Make_Raise_Constraint_Error (Loc,
3812 Left_Opnd => New_Occurrence_Of (Tnn, Loc),
3813 Right_Opnd => New_Occurrence_Of (Target_Type, Loc)),
3815 Reason => Reason)));
3817 Rewrite (N, New_Occurrence_Of (Tnn, Loc));
3820 -- At this stage, we know that we have two scalar types, which are
3821 -- directly convertible, and where neither scalar type has a base
3822 -- range that is in the range of the other scalar type.
3824 -- The only way this can happen is with a signed and unsigned type.
3825 -- So test for these two cases:
3828 -- Case of the source is unsigned and the target is signed
3830 if Is_Unsigned_Type (Source_Base_Type)
3831 and then not Is_Unsigned_Type (Target_Base_Type)
3833 -- If the source is unsigned and the target is signed, then we
3834 -- know that the source is not shorter than the target (otherwise
3835 -- the source base type would be in the target base type range).
3837 -- In other words, the unsigned type is either the same size
3838 -- as the target, or it is larger. It cannot be smaller.
3841 (Esize (Source_Base_Type) >= Esize (Target_Base_Type));
3843 -- We only need to check the low bound if the low bound of the
3844 -- target type is non-negative. If the low bound of the target
3845 -- type is negative, then we know that we will fit fine.
3847 -- If the high bound of the target type is negative, then we
3848 -- know we have a constraint error, since we can't possibly
3849 -- have a negative source.
3851 -- With these two checks out of the way, we can do the check
3852 -- using the source type safely
3854 -- This is definitely the most annoying case!
3856 -- [constraint_error
3857 -- when (Target_Type'First >= 0
3859 -- N < Source_Base_Type (Target_Type'First))
3860 -- or else Target_Type'Last < 0
3861 -- or else N > Source_Base_Type (Target_Type'Last)];
3863 -- We turn off all checks since we know that the conversions
3864 -- will work fine, given the guards for negative values.
3867 Make_Raise_Constraint_Error (Loc,
3873 Left_Opnd => Make_Op_Ge (Loc,
3875 Make_Attribute_Reference (Loc,
3877 New_Occurrence_Of (Target_Type, Loc),
3878 Attribute_Name => Name_First),
3879 Right_Opnd => Make_Integer_Literal (Loc, Uint_0)),
3883 Left_Opnd => Duplicate_Subexpr (N),
3885 Convert_To (Source_Base_Type,
3886 Make_Attribute_Reference (Loc,
3888 New_Occurrence_Of (Target_Type, Loc),
3889 Attribute_Name => Name_First)))),
3894 Make_Attribute_Reference (Loc,
3895 Prefix => New_Occurrence_Of (Target_Type, Loc),
3896 Attribute_Name => Name_Last),
3897 Right_Opnd => Make_Integer_Literal (Loc, Uint_0))),
3901 Left_Opnd => Duplicate_Subexpr (N),
3903 Convert_To (Source_Base_Type,
3904 Make_Attribute_Reference (Loc,
3905 Prefix => New_Occurrence_Of (Target_Type, Loc),
3906 Attribute_Name => Name_Last)))),
3909 Suppress => All_Checks);
3911 -- Only remaining possibility is that the source is signed and
3912 -- the target is unsigned
3915 pragma Assert (not Is_Unsigned_Type (Source_Base_Type)
3916 and then Is_Unsigned_Type (Target_Base_Type));
3918 -- If the source is signed and the target is unsigned, then
3919 -- we know that the target is not shorter than the source
3920 -- (otherwise the target base type would be in the source
3921 -- base type range).
3923 -- In other words, the unsigned type is either the same size
3924 -- as the target, or it is larger. It cannot be smaller.
3926 -- Clearly we have an error if the source value is negative
3927 -- since no unsigned type can have negative values. If the
3928 -- source type is non-negative, then the check can be done
3929 -- using the target type.
3931 -- Tnn : constant Target_Base_Type (N) := Target_Type;
3933 -- [constraint_error
3934 -- when N < 0 or else Tnn not in Target_Type];
3936 -- We turn off all checks for the conversion of N to the
3937 -- target base type, since we generate the explicit check
3938 -- to ensure that the value is non-negative
3941 Tnn : constant Entity_Id :=
3942 Make_Defining_Identifier (Loc,
3943 Chars => New_Internal_Name ('T'));
3946 Insert_Actions (N, New_List (
3947 Make_Object_Declaration (Loc,
3948 Defining_Identifier => Tnn,
3949 Object_Definition =>
3950 New_Occurrence_Of (Target_Base_Type, Loc),
3951 Constant_Present => True,
3953 Make_Type_Conversion (Loc,
3955 New_Occurrence_Of (Target_Base_Type, Loc),
3956 Expression => Duplicate_Subexpr (N))),
3958 Make_Raise_Constraint_Error (Loc,
3963 Left_Opnd => Duplicate_Subexpr (N),
3964 Right_Opnd => Make_Integer_Literal (Loc, Uint_0)),
3968 Left_Opnd => New_Occurrence_Of (Tnn, Loc),
3970 New_Occurrence_Of (Target_Type, Loc))),
3973 Suppress => All_Checks);
3975 -- Set the Etype explicitly, because Insert_Actions may
3976 -- have placed the declaration in the freeze list for an
3977 -- enclosing construct, and thus it is not analyzed yet.
3979 Set_Etype (Tnn, Target_Base_Type);
3980 Rewrite (N, New_Occurrence_Of (Tnn, Loc));
3984 end Generate_Range_Check;
3986 ---------------------
3987 -- Get_Discriminal --
3988 ---------------------
3990 function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is
3991 Loc : constant Source_Ptr := Sloc (E);
3996 -- The entity E is the type of a private component of the protected
3997 -- type, or the type of a renaming of that component within a protected
3998 -- operation of that type.
4002 if Ekind (Sc) /= E_Protected_Type then
4005 if Ekind (Sc) /= E_Protected_Type then
4010 D := First_Discriminant (Sc);
4013 and then Chars (D) /= Chars (Bound)
4015 Next_Discriminant (D);
4018 return New_Occurrence_Of (Discriminal (D), Loc);
4019 end Get_Discriminal;
4025 function Guard_Access
4032 if Nkind (Cond) = N_Or_Else then
4033 Set_Paren_Count (Cond, 1);
4036 if Nkind (Ck_Node) = N_Allocator then
4043 Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
4044 Right_Opnd => Make_Null (Loc)),
4045 Right_Opnd => Cond);
4049 -----------------------------
4050 -- Index_Checks_Suppressed --
4051 -----------------------------
4053 function Index_Checks_Suppressed (E : Entity_Id) return Boolean is
4055 if Present (E) and then Checks_May_Be_Suppressed (E) then
4056 return Is_Check_Suppressed (E, Index_Check);
4058 return Scope_Suppress (Index_Check);
4060 end Index_Checks_Suppressed;
4066 procedure Initialize is
4068 for J in Determine_Range_Cache_N'Range loop
4069 Determine_Range_Cache_N (J) := Empty;
4073 -------------------------
4074 -- Insert_Range_Checks --
4075 -------------------------
4077 procedure Insert_Range_Checks
4078 (Checks : Check_Result;
4080 Suppress_Typ : Entity_Id;
4081 Static_Sloc : Source_Ptr := No_Location;
4082 Flag_Node : Node_Id := Empty;
4083 Do_Before : Boolean := False)
4085 Internal_Flag_Node : Node_Id := Flag_Node;
4086 Internal_Static_Sloc : Source_Ptr := Static_Sloc;
4088 Check_Node : Node_Id;
4089 Checks_On : constant Boolean :=
4090 (not Index_Checks_Suppressed (Suppress_Typ))
4092 (not Range_Checks_Suppressed (Suppress_Typ));
4095 -- For now we just return if Checks_On is false, however this should
4096 -- be enhanced to check for an always True value in the condition
4097 -- and to generate a compilation warning???
4099 if not Expander_Active or else not Checks_On then
4103 if Static_Sloc = No_Location then
4104 Internal_Static_Sloc := Sloc (Node);
4107 if No (Flag_Node) then
4108 Internal_Flag_Node := Node;
4111 for J in 1 .. 2 loop
4112 exit when No (Checks (J));
4114 if Nkind (Checks (J)) = N_Raise_Constraint_Error
4115 and then Present (Condition (Checks (J)))
4117 if not Has_Dynamic_Range_Check (Internal_Flag_Node) then
4118 Check_Node := Checks (J);
4119 Mark_Rewrite_Insertion (Check_Node);
4122 Insert_Before_And_Analyze (Node, Check_Node);
4124 Insert_After_And_Analyze (Node, Check_Node);
4127 Set_Has_Dynamic_Range_Check (Internal_Flag_Node);
4132 Make_Raise_Constraint_Error (Internal_Static_Sloc,
4133 Reason => CE_Range_Check_Failed);
4134 Mark_Rewrite_Insertion (Check_Node);
4137 Insert_Before_And_Analyze (Node, Check_Node);
4139 Insert_After_And_Analyze (Node, Check_Node);
4143 end Insert_Range_Checks;
4145 ------------------------
4146 -- Insert_Valid_Check --
4147 ------------------------
4149 procedure Insert_Valid_Check (Expr : Node_Id) is
4150 Loc : constant Source_Ptr := Sloc (Expr);
4154 -- Do not insert if checks off, or if not checking validity
4156 if Range_Checks_Suppressed (Etype (Expr))
4157 or else (not Validity_Checks_On)
4162 -- If we have a checked conversion, then validity check applies to
4163 -- the expression inside the conversion, not the result, since if
4164 -- the expression inside is valid, then so is the conversion result.
4167 while Nkind (Exp) = N_Type_Conversion loop
4168 Exp := Expression (Exp);
4171 -- Insert the validity check. Note that we do this with validity
4172 -- checks turned off, to avoid recursion, we do not want validity
4173 -- checks on the validity checking code itself!
4175 Validity_Checks_On := False;
4178 Make_Raise_Constraint_Error (Loc,
4182 Make_Attribute_Reference (Loc,
4184 Duplicate_Subexpr_No_Checks (Exp, Name_Req => True),
4185 Attribute_Name => Name_Valid)),
4186 Reason => CE_Invalid_Data),
4187 Suppress => All_Checks);
4188 Validity_Checks_On := True;
4189 end Insert_Valid_Check;
4191 --------------------------
4192 -- Install_Static_Check --
4193 --------------------------
4195 procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is
4196 Stat : constant Boolean := Is_Static_Expression (R_Cno);
4197 Typ : constant Entity_Id := Etype (R_Cno);
4201 Make_Raise_Constraint_Error (Loc,
4202 Reason => CE_Range_Check_Failed));
4203 Set_Analyzed (R_Cno);
4204 Set_Etype (R_Cno, Typ);
4205 Set_Raises_Constraint_Error (R_Cno);
4206 Set_Is_Static_Expression (R_Cno, Stat);
4207 end Install_Static_Check;
4209 ---------------------
4210 -- Kill_All_Checks --
4211 ---------------------
4213 procedure Kill_All_Checks is
4215 if Debug_Flag_CC then
4216 w ("Kill_All_Checks");
4219 -- We reset the number of saved checks to zero, and also modify
4220 -- all stack entries for statement ranges to indicate that the
4221 -- number of checks at each level is now zero.
4223 Num_Saved_Checks := 0;
4225 for J in 1 .. Saved_Checks_TOS loop
4226 Saved_Checks_Stack (J) := 0;
4228 end Kill_All_Checks;
4234 procedure Kill_Checks (V : Entity_Id) is
4236 if Debug_Flag_CC then
4237 w ("Kill_Checks for entity", Int (V));
4240 for J in 1 .. Num_Saved_Checks loop
4241 if Saved_Checks (J).Entity = V then
4242 if Debug_Flag_CC then
4243 w (" Checks killed for saved check ", J);
4246 Saved_Checks (J).Killed := True;
4251 ------------------------------
4252 -- Length_Checks_Suppressed --
4253 ------------------------------
4255 function Length_Checks_Suppressed (E : Entity_Id) return Boolean is
4257 if Present (E) and then Checks_May_Be_Suppressed (E) then
4258 return Is_Check_Suppressed (E, Length_Check);
4260 return Scope_Suppress (Length_Check);
4262 end Length_Checks_Suppressed;
4264 --------------------------------
4265 -- Overflow_Checks_Suppressed --
4266 --------------------------------
4268 function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is
4270 if Present (E) and then Checks_May_Be_Suppressed (E) then
4271 return Is_Check_Suppressed (E, Overflow_Check);
4273 return Scope_Suppress (Overflow_Check);
4275 end Overflow_Checks_Suppressed;
4281 function Range_Check
4283 Target_Typ : Entity_Id;
4284 Source_Typ : Entity_Id := Empty;
4285 Warn_Node : Node_Id := Empty)
4289 return Selected_Range_Checks
4290 (Ck_Node, Target_Typ, Source_Typ, Warn_Node);
4293 -----------------------------
4294 -- Range_Checks_Suppressed --
4295 -----------------------------
4297 function Range_Checks_Suppressed (E : Entity_Id) return Boolean is
4301 -- Note: for now we always suppress range checks on Vax float types,
4302 -- since Gigi does not know how to generate these checks.
4304 if Vax_Float (E) then
4306 elsif Kill_Range_Checks (E) then
4308 elsif Checks_May_Be_Suppressed (E) then
4309 return Is_Check_Suppressed (E, Range_Check);
4313 return Scope_Suppress (Range_Check);
4314 end Range_Checks_Suppressed;
4320 procedure Remove_Checks (Expr : Node_Id) is
4321 Discard : Traverse_Result;
4322 pragma Warnings (Off, Discard);
4324 function Process (N : Node_Id) return Traverse_Result;
4325 -- Process a single node during the traversal
4327 function Traverse is new Traverse_Func (Process);
4328 -- The traversal function itself
4334 function Process (N : Node_Id) return Traverse_Result is
4336 if Nkind (N) not in N_Subexpr then
4340 Set_Do_Range_Check (N, False);
4344 Discard := Traverse (Left_Opnd (N));
4347 when N_Attribute_Reference =>
4348 Set_Do_Overflow_Check (N, False);
4350 when N_Function_Call =>
4351 Set_Do_Tag_Check (N, False);
4354 Set_Do_Overflow_Check (N, False);
4358 Set_Do_Division_Check (N, False);
4361 Set_Do_Length_Check (N, False);
4364 Set_Do_Division_Check (N, False);
4367 Set_Do_Length_Check (N, False);
4370 Set_Do_Division_Check (N, False);
4373 Set_Do_Length_Check (N, False);
4380 Discard := Traverse (Left_Opnd (N));
4383 when N_Selected_Component =>
4384 Set_Do_Discriminant_Check (N, False);
4386 when N_Type_Conversion =>
4387 Set_Do_Length_Check (N, False);
4388 Set_Do_Tag_Check (N, False);
4389 Set_Do_Overflow_Check (N, False);
4398 -- Start of processing for Remove_Checks
4401 Discard := Traverse (Expr);
4404 ----------------------------
4405 -- Selected_Length_Checks --
4406 ----------------------------
4408 function Selected_Length_Checks
4410 Target_Typ : Entity_Id;
4411 Source_Typ : Entity_Id;
4412 Warn_Node : Node_Id)
4415 Loc : constant Source_Ptr := Sloc (Ck_Node);
4418 Expr_Actual : Node_Id;
4420 Cond : Node_Id := Empty;
4421 Do_Access : Boolean := False;
4422 Wnode : Node_Id := Warn_Node;
4423 Ret_Result : Check_Result := (Empty, Empty);
4424 Num_Checks : Natural := 0;
4426 procedure Add_Check (N : Node_Id);
4427 -- Adds the action given to Ret_Result if N is non-Empty
4429 function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id;
4430 function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id;
4432 function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean;
4433 -- True for equal literals and for nodes that denote the same constant
4434 -- entity, even if its value is not a static constant. This includes the
4435 -- case of a discriminal reference within an init proc. Removes some
4436 -- obviously superfluous checks.
4438 function Length_E_Cond
4439 (Exptyp : Entity_Id;
4443 -- Returns expression to compute:
4444 -- Typ'Length /= Exptyp'Length
4446 function Length_N_Cond
4451 -- Returns expression to compute:
4452 -- Typ'Length /= Expr'Length
4458 procedure Add_Check (N : Node_Id) is
4462 -- For now, ignore attempt to place more than 2 checks ???
4464 if Num_Checks = 2 then
4468 pragma Assert (Num_Checks <= 1);
4469 Num_Checks := Num_Checks + 1;
4470 Ret_Result (Num_Checks) := N;
4478 function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is
4479 Pt : constant Entity_Id := Scope (Scope (E));
4481 E1 : Entity_Id := E;
4484 if Ekind (Scope (E)) = E_Record_Type
4485 and then Has_Discriminants (Scope (E))
4487 N := Build_Discriminal_Subtype_Of_Component (E);
4490 Insert_Action (Ck_Node, N);
4491 E1 := Defining_Identifier (N);
4495 if Ekind (E1) = E_String_Literal_Subtype then
4497 Make_Integer_Literal (Loc,
4498 Intval => String_Literal_Length (E1));
4500 elsif Ekind (Pt) = E_Protected_Type
4501 and then Has_Discriminants (Pt)
4502 and then Has_Completion (Pt)
4503 and then not Inside_Init_Proc
4506 -- If the type whose length is needed is a private component
4507 -- constrained by a discriminant, we must expand the 'Length
4508 -- attribute into an explicit computation, using the discriminal
4509 -- of the current protected operation. This is because the actual
4510 -- type of the prival is constructed after the protected opera-
4511 -- tion has been fully expanded.
4514 Indx_Type : Node_Id;
4517 Do_Expand : Boolean := False;
4520 Indx_Type := First_Index (E);
4522 for J in 1 .. Indx - 1 loop
4523 Next_Index (Indx_Type);
4526 Get_Index_Bounds (Indx_Type, Lo, Hi);
4528 if Nkind (Lo) = N_Identifier
4529 and then Ekind (Entity (Lo)) = E_In_Parameter
4531 Lo := Get_Discriminal (E, Lo);
4535 if Nkind (Hi) = N_Identifier
4536 and then Ekind (Entity (Hi)) = E_In_Parameter
4538 Hi := Get_Discriminal (E, Hi);
4543 if not Is_Entity_Name (Lo) then
4544 Lo := Duplicate_Subexpr_No_Checks (Lo);
4547 if not Is_Entity_Name (Hi) then
4548 Lo := Duplicate_Subexpr_No_Checks (Hi);
4554 Make_Op_Subtract (Loc,
4558 Right_Opnd => Make_Integer_Literal (Loc, 1));
4563 Make_Attribute_Reference (Loc,
4564 Attribute_Name => Name_Length,
4566 New_Occurrence_Of (E1, Loc));
4569 Set_Expressions (N, New_List (
4570 Make_Integer_Literal (Loc, Indx)));
4579 Make_Attribute_Reference (Loc,
4580 Attribute_Name => Name_Length,
4582 New_Occurrence_Of (E1, Loc));
4585 Set_Expressions (N, New_List (
4586 Make_Integer_Literal (Loc, Indx)));
4598 function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is
4601 Make_Attribute_Reference (Loc,
4602 Attribute_Name => Name_Length,
4604 Duplicate_Subexpr_No_Checks (N, Name_Req => True),
4605 Expressions => New_List (
4606 Make_Integer_Literal (Loc, Indx)));
4614 function Length_E_Cond
4615 (Exptyp : Entity_Id;
4623 Left_Opnd => Get_E_Length (Typ, Indx),
4624 Right_Opnd => Get_E_Length (Exptyp, Indx));
4632 function Length_N_Cond
4641 Left_Opnd => Get_E_Length (Typ, Indx),
4642 Right_Opnd => Get_N_Length (Expr, Indx));
4646 function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is
4649 (Nkind (L) = N_Integer_Literal
4650 and then Nkind (R) = N_Integer_Literal
4651 and then Intval (L) = Intval (R))
4655 and then Ekind (Entity (L)) = E_Constant
4656 and then ((Is_Entity_Name (R)
4657 and then Entity (L) = Entity (R))
4659 (Nkind (R) = N_Type_Conversion
4660 and then Is_Entity_Name (Expression (R))
4661 and then Entity (L) = Entity (Expression (R)))))
4665 and then Ekind (Entity (R)) = E_Constant
4666 and then Nkind (L) = N_Type_Conversion
4667 and then Is_Entity_Name (Expression (L))
4668 and then Entity (R) = Entity (Expression (L)))
4672 and then Is_Entity_Name (R)
4673 and then Entity (L) = Entity (R)
4674 and then Ekind (Entity (L)) = E_In_Parameter
4675 and then Inside_Init_Proc);
4678 -- Start of processing for Selected_Length_Checks
4681 if not Expander_Active then
4685 if Target_Typ = Any_Type
4686 or else Target_Typ = Any_Composite
4687 or else Raises_Constraint_Error (Ck_Node)
4696 T_Typ := Target_Typ;
4698 if No (Source_Typ) then
4699 S_Typ := Etype (Ck_Node);
4701 S_Typ := Source_Typ;
4704 if S_Typ = Any_Type or else S_Typ = Any_Composite then
4708 if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then
4709 S_Typ := Designated_Type (S_Typ);
4710 T_Typ := Designated_Type (T_Typ);
4713 -- A simple optimization
4715 if Nkind (Ck_Node) = N_Null then
4720 if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then
4721 if Is_Constrained (T_Typ) then
4723 -- The checking code to be generated will freeze the
4724 -- corresponding array type. However, we must freeze the
4725 -- type now, so that the freeze node does not appear within
4726 -- the generated condional expression, but ahead of it.
4728 Freeze_Before (Ck_Node, T_Typ);
4730 Expr_Actual := Get_Referenced_Object (Ck_Node);
4731 Exptyp := Get_Actual_Subtype (Expr_Actual);
4733 if Is_Access_Type (Exptyp) then
4734 Exptyp := Designated_Type (Exptyp);
4737 -- String_Literal case. This needs to be handled specially be-
4738 -- cause no index types are available for string literals. The
4739 -- condition is simply:
4741 -- T_Typ'Length = string-literal-length
4743 if Nkind (Expr_Actual) = N_String_Literal
4744 and then Ekind (Etype (Expr_Actual)) = E_String_Literal_Subtype
4748 Left_Opnd => Get_E_Length (T_Typ, 1),
4750 Make_Integer_Literal (Loc,
4752 String_Literal_Length (Etype (Expr_Actual))));
4754 -- General array case. Here we have a usable actual subtype for
4755 -- the expression, and the condition is built from the two types
4758 -- T_Typ'Length /= Exptyp'Length or else
4759 -- T_Typ'Length (2) /= Exptyp'Length (2) or else
4760 -- T_Typ'Length (3) /= Exptyp'Length (3) or else
4763 elsif Is_Constrained (Exptyp) then
4765 Ndims : constant Nat := Number_Dimensions (T_Typ);
4779 -- At the library level, we need to ensure that the
4780 -- type of the object is elaborated before the check
4781 -- itself is emitted.
4783 if Is_Itype (Exptyp)
4785 Ekind (Cunit_Entity (Current_Sem_Unit)) = E_Package
4787 not In_Package_Body (Cunit_Entity (Current_Sem_Unit))
4789 Ref_Node := Make_Itype_Reference (Sloc (Ck_Node));
4790 Set_Itype (Ref_Node, Exptyp);
4791 Insert_Action (Ck_Node, Ref_Node);
4794 L_Index := First_Index (T_Typ);
4795 R_Index := First_Index (Exptyp);
4797 for Indx in 1 .. Ndims loop
4798 if not (Nkind (L_Index) = N_Raise_Constraint_Error
4800 Nkind (R_Index) = N_Raise_Constraint_Error)
4802 Get_Index_Bounds (L_Index, L_Low, L_High);
4803 Get_Index_Bounds (R_Index, R_Low, R_High);
4805 -- Deal with compile time length check. Note that we
4806 -- skip this in the access case, because the access
4807 -- value may be null, so we cannot know statically.
4810 and then Compile_Time_Known_Value (L_Low)
4811 and then Compile_Time_Known_Value (L_High)
4812 and then Compile_Time_Known_Value (R_Low)
4813 and then Compile_Time_Known_Value (R_High)
4815 if Expr_Value (L_High) >= Expr_Value (L_Low) then
4816 L_Length := Expr_Value (L_High) -
4817 Expr_Value (L_Low) + 1;
4819 L_Length := UI_From_Int (0);
4822 if Expr_Value (R_High) >= Expr_Value (R_Low) then
4823 R_Length := Expr_Value (R_High) -
4824 Expr_Value (R_Low) + 1;
4826 R_Length := UI_From_Int (0);
4829 if L_Length > R_Length then
4831 (Compile_Time_Constraint_Error
4832 (Wnode, "too few elements for}?", T_Typ));
4834 elsif L_Length < R_Length then
4836 (Compile_Time_Constraint_Error
4837 (Wnode, "too many elements for}?", T_Typ));
4840 -- The comparison for an individual index subtype
4841 -- is omitted if the corresponding index subtypes
4842 -- statically match, since the result is known to
4843 -- be true. Note that this test is worth while even
4844 -- though we do static evaluation, because non-static
4845 -- subtypes can statically match.
4848 Subtypes_Statically_Match
4849 (Etype (L_Index), Etype (R_Index))
4852 (Same_Bounds (L_Low, R_Low)
4853 and then Same_Bounds (L_High, R_High))
4856 (Cond, Length_E_Cond (Exptyp, T_Typ, Indx));
4865 -- Handle cases where we do not get a usable actual subtype that
4866 -- is constrained. This happens for example in the function call
4867 -- and explicit dereference cases. In these cases, we have to get
4868 -- the length or range from the expression itself, making sure we
4869 -- do not evaluate it more than once.
4871 -- Here Ck_Node is the original expression, or more properly the
4872 -- result of applying Duplicate_Expr to the original tree,
4873 -- forcing the result to be a name.
4877 Ndims : constant Nat := Number_Dimensions (T_Typ);
4880 -- Build the condition for the explicit dereference case
4882 for Indx in 1 .. Ndims loop
4884 (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx));
4891 -- Construct the test and insert into the tree
4893 if Present (Cond) then
4895 Cond := Guard_Access (Cond, Loc, Ck_Node);
4899 (Make_Raise_Constraint_Error (Loc,
4901 Reason => CE_Length_Check_Failed));
4905 end Selected_Length_Checks;
4907 ---------------------------
4908 -- Selected_Range_Checks --
4909 ---------------------------
4911 function Selected_Range_Checks
4913 Target_Typ : Entity_Id;
4914 Source_Typ : Entity_Id;
4915 Warn_Node : Node_Id)
4918 Loc : constant Source_Ptr := Sloc (Ck_Node);
4921 Expr_Actual : Node_Id;
4923 Cond : Node_Id := Empty;
4924 Do_Access : Boolean := False;
4925 Wnode : Node_Id := Warn_Node;
4926 Ret_Result : Check_Result := (Empty, Empty);
4927 Num_Checks : Integer := 0;
4929 procedure Add_Check (N : Node_Id);
4930 -- Adds the action given to Ret_Result if N is non-Empty
4932 function Discrete_Range_Cond
4936 -- Returns expression to compute:
4937 -- Low_Bound (Expr) < Typ'First
4939 -- High_Bound (Expr) > Typ'Last
4941 function Discrete_Expr_Cond
4945 -- Returns expression to compute:
4950 function Get_E_First_Or_Last
4955 -- Returns expression to compute:
4956 -- E'First or E'Last
4958 function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id;
4959 function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id;
4960 -- Returns expression to compute:
4961 -- N'First or N'Last using Duplicate_Subexpr_No_Checks
4963 function Range_E_Cond
4964 (Exptyp : Entity_Id;
4968 -- Returns expression to compute:
4969 -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
4971 function Range_Equal_E_Cond
4972 (Exptyp : Entity_Id;
4976 -- Returns expression to compute:
4977 -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
4979 function Range_N_Cond
4984 -- Return expression to compute:
4985 -- Expr'First < Typ'First or else Expr'Last > Typ'Last
4991 procedure Add_Check (N : Node_Id) is
4995 -- For now, ignore attempt to place more than 2 checks ???
4997 if Num_Checks = 2 then
5001 pragma Assert (Num_Checks <= 1);
5002 Num_Checks := Num_Checks + 1;
5003 Ret_Result (Num_Checks) := N;
5007 -------------------------
5008 -- Discrete_Expr_Cond --
5009 -------------------------
5011 function Discrete_Expr_Cond
5022 Convert_To (Base_Type (Typ),
5023 Duplicate_Subexpr_No_Checks (Expr)),
5025 Convert_To (Base_Type (Typ),
5026 Get_E_First_Or_Last (Typ, 0, Name_First))),
5031 Convert_To (Base_Type (Typ),
5032 Duplicate_Subexpr_No_Checks (Expr)),
5036 Get_E_First_Or_Last (Typ, 0, Name_Last))));
5037 end Discrete_Expr_Cond;
5039 -------------------------
5040 -- Discrete_Range_Cond --
5041 -------------------------
5043 function Discrete_Range_Cond
5048 LB : Node_Id := Low_Bound (Expr);
5049 HB : Node_Id := High_Bound (Expr);
5051 Left_Opnd : Node_Id;
5052 Right_Opnd : Node_Id;
5055 if Nkind (LB) = N_Identifier
5056 and then Ekind (Entity (LB)) = E_Discriminant then
5057 LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc);
5060 if Nkind (HB) = N_Identifier
5061 and then Ekind (Entity (HB)) = E_Discriminant then
5062 HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc);
5069 (Base_Type (Typ), Duplicate_Subexpr_No_Checks (LB)),
5073 (Base_Type (Typ), Get_E_First_Or_Last (Typ, 0, Name_First)));
5075 if Base_Type (Typ) = Typ then
5078 elsif Compile_Time_Known_Value (High_Bound (Scalar_Range (Typ)))
5080 Compile_Time_Known_Value (High_Bound (Scalar_Range
5083 if Is_Floating_Point_Type (Typ) then
5084 if Expr_Value_R (High_Bound (Scalar_Range (Typ))) =
5085 Expr_Value_R (High_Bound (Scalar_Range (Base_Type (Typ))))
5091 if Expr_Value (High_Bound (Scalar_Range (Typ))) =
5092 Expr_Value (High_Bound (Scalar_Range (Base_Type (Typ))))
5103 (Base_Type (Typ), Duplicate_Subexpr_No_Checks (HB)),
5108 Get_E_First_Or_Last (Typ, 0, Name_Last)));
5110 return Make_Or_Else (Loc, Left_Opnd, Right_Opnd);
5111 end Discrete_Range_Cond;
5113 -------------------------
5114 -- Get_E_First_Or_Last --
5115 -------------------------
5117 function Get_E_First_Or_Last
5129 if Is_Array_Type (E) then
5130 N := First_Index (E);
5132 for J in 2 .. Indx loop
5137 N := Scalar_Range (E);
5140 if Nkind (N) = N_Subtype_Indication then
5141 LB := Low_Bound (Range_Expression (Constraint (N)));
5142 HB := High_Bound (Range_Expression (Constraint (N)));
5144 elsif Is_Entity_Name (N) then
5145 LB := Type_Low_Bound (Etype (N));
5146 HB := Type_High_Bound (Etype (N));
5149 LB := Low_Bound (N);
5150 HB := High_Bound (N);
5153 if Nam = Name_First then
5159 if Nkind (Bound) = N_Identifier
5160 and then Ekind (Entity (Bound)) = E_Discriminant
5162 -- If this is a task discriminant, and we are the body, we must
5163 -- retrieve the corresponding body discriminal. This is another
5164 -- consequence of the early creation of discriminals, and the
5165 -- need to generate constraint checks before their declarations
5166 -- are made visible.
5168 if Is_Concurrent_Record_Type (Scope (Entity (Bound))) then
5170 Tsk : constant Entity_Id :=
5171 Corresponding_Concurrent_Type
5172 (Scope (Entity (Bound)));
5176 if In_Open_Scopes (Tsk)
5177 and then Has_Completion (Tsk)
5179 -- Find discriminant of original task, and use its
5180 -- current discriminal, which is the renaming within
5183 Disc := First_Discriminant (Tsk);
5184 while Present (Disc) loop
5185 if Chars (Disc) = Chars (Entity (Bound)) then
5186 Set_Scope (Discriminal (Disc), Tsk);
5187 return New_Occurrence_Of (Discriminal (Disc), Loc);
5190 Next_Discriminant (Disc);
5193 -- That loop should always succeed in finding a matching
5194 -- entry and returning. Fatal error if not.
5196 raise Program_Error;
5200 New_Occurrence_Of (Discriminal (Entity (Bound)), Loc);
5204 return New_Occurrence_Of (Discriminal (Entity (Bound)), Loc);
5207 elsif Nkind (Bound) = N_Identifier
5208 and then Ekind (Entity (Bound)) = E_In_Parameter
5209 and then not Inside_Init_Proc
5211 return Get_Discriminal (E, Bound);
5213 elsif Nkind (Bound) = N_Integer_Literal then
5214 return Make_Integer_Literal (Loc, Intval (Bound));
5217 return Duplicate_Subexpr_No_Checks (Bound);
5219 end Get_E_First_Or_Last;
5225 function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is
5228 Make_Attribute_Reference (Loc,
5229 Attribute_Name => Name_First,
5231 Duplicate_Subexpr_No_Checks (N, Name_Req => True),
5232 Expressions => New_List (
5233 Make_Integer_Literal (Loc, Indx)));
5241 function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is
5244 Make_Attribute_Reference (Loc,
5245 Attribute_Name => Name_Last,
5247 Duplicate_Subexpr_No_Checks (N, Name_Req => True),
5248 Expressions => New_List (
5249 Make_Integer_Literal (Loc, Indx)));
5257 function Range_E_Cond
5258 (Exptyp : Entity_Id;
5268 Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_First),
5269 Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)),
5273 Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_Last),
5274 Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last)));
5278 ------------------------
5279 -- Range_Equal_E_Cond --
5280 ------------------------
5282 function Range_Equal_E_Cond
5283 (Exptyp : Entity_Id;
5293 Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_First),
5294 Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)),
5297 Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_Last),
5298 Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last)));
5299 end Range_Equal_E_Cond;
5305 function Range_N_Cond
5316 Left_Opnd => Get_N_First (Expr, Indx),
5317 Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)),
5321 Left_Opnd => Get_N_Last (Expr, Indx),
5322 Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last)));
5325 -- Start of processing for Selected_Range_Checks
5328 if not Expander_Active then
5332 if Target_Typ = Any_Type
5333 or else Target_Typ = Any_Composite
5334 or else Raises_Constraint_Error (Ck_Node)
5343 T_Typ := Target_Typ;
5345 if No (Source_Typ) then
5346 S_Typ := Etype (Ck_Node);
5348 S_Typ := Source_Typ;
5351 if S_Typ = Any_Type or else S_Typ = Any_Composite then
5355 -- The order of evaluating T_Typ before S_Typ seems to be critical
5356 -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
5357 -- in, and since Node can be an N_Range node, it might be invalid.
5358 -- Should there be an assert check somewhere for taking the Etype of
5359 -- an N_Range node ???
5361 if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then
5362 S_Typ := Designated_Type (S_Typ);
5363 T_Typ := Designated_Type (T_Typ);
5366 -- A simple optimization
5368 if Nkind (Ck_Node) = N_Null then
5373 -- For an N_Range Node, check for a null range and then if not
5374 -- null generate a range check action.
5376 if Nkind (Ck_Node) = N_Range then
5378 -- There's no point in checking a range against itself
5380 if Ck_Node = Scalar_Range (T_Typ) then
5385 T_LB : constant Node_Id := Type_Low_Bound (T_Typ);
5386 T_HB : constant Node_Id := Type_High_Bound (T_Typ);
5387 LB : constant Node_Id := Low_Bound (Ck_Node);
5388 HB : constant Node_Id := High_Bound (Ck_Node);
5389 Null_Range : Boolean;
5391 Out_Of_Range_L : Boolean;
5392 Out_Of_Range_H : Boolean;
5395 -- Check for case where everything is static and we can
5396 -- do the check at compile time. This is skipped if we
5397 -- have an access type, since the access value may be null.
5399 -- ??? This code can be improved since you only need to know
5400 -- that the two respective bounds (LB & T_LB or HB & T_HB)
5401 -- are known at compile time to emit pertinent messages.
5403 if Compile_Time_Known_Value (LB)
5404 and then Compile_Time_Known_Value (HB)
5405 and then Compile_Time_Known_Value (T_LB)
5406 and then Compile_Time_Known_Value (T_HB)
5407 and then not Do_Access
5409 -- Floating-point case
5411 if Is_Floating_Point_Type (S_Typ) then
5412 Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB);
5414 (Expr_Value_R (LB) < Expr_Value_R (T_LB))
5416 (Expr_Value_R (LB) > Expr_Value_R (T_HB));
5419 (Expr_Value_R (HB) > Expr_Value_R (T_HB))
5421 (Expr_Value_R (HB) < Expr_Value_R (T_LB));
5423 -- Fixed or discrete type case
5426 Null_Range := Expr_Value (HB) < Expr_Value (LB);
5428 (Expr_Value (LB) < Expr_Value (T_LB))
5430 (Expr_Value (LB) > Expr_Value (T_HB));
5433 (Expr_Value (HB) > Expr_Value (T_HB))
5435 (Expr_Value (HB) < Expr_Value (T_LB));
5438 if not Null_Range then
5439 if Out_Of_Range_L then
5440 if No (Warn_Node) then
5442 (Compile_Time_Constraint_Error
5443 (Low_Bound (Ck_Node),
5444 "static value out of range of}?", T_Typ));
5448 (Compile_Time_Constraint_Error
5450 "static range out of bounds of}?", T_Typ));
5454 if Out_Of_Range_H then
5455 if No (Warn_Node) then
5457 (Compile_Time_Constraint_Error
5458 (High_Bound (Ck_Node),
5459 "static value out of range of}?", T_Typ));
5463 (Compile_Time_Constraint_Error
5465 "static range out of bounds of}?", T_Typ));
5473 LB : Node_Id := Low_Bound (Ck_Node);
5474 HB : Node_Id := High_Bound (Ck_Node);
5478 -- If either bound is a discriminant and we are within
5479 -- the record declaration, it is a use of the discriminant
5480 -- in a constraint of a component, and nothing can be
5481 -- checked here. The check will be emitted within the
5482 -- init proc. Before then, the discriminal has no real
5485 if Nkind (LB) = N_Identifier
5486 and then Ekind (Entity (LB)) = E_Discriminant
5488 if Current_Scope = Scope (Entity (LB)) then
5492 New_Occurrence_Of (Discriminal (Entity (LB)), Loc);
5496 if Nkind (HB) = N_Identifier
5497 and then Ekind (Entity (HB)) = E_Discriminant
5499 if Current_Scope = Scope (Entity (HB)) then
5503 New_Occurrence_Of (Discriminal (Entity (HB)), Loc);
5507 Cond := Discrete_Range_Cond (Ck_Node, T_Typ);
5508 Set_Paren_Count (Cond, 1);
5514 Left_Opnd => Duplicate_Subexpr_No_Checks (HB),
5515 Right_Opnd => Duplicate_Subexpr_No_Checks (LB)),
5516 Right_Opnd => Cond);
5522 elsif Is_Scalar_Type (S_Typ) then
5524 -- This somewhat duplicates what Apply_Scalar_Range_Check does,
5525 -- except the above simply sets a flag in the node and lets
5526 -- gigi generate the check base on the Etype of the expression.
5527 -- Sometimes, however we want to do a dynamic check against an
5528 -- arbitrary target type, so we do that here.
5530 if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then
5531 Cond := Discrete_Expr_Cond (Ck_Node, T_Typ);
5533 -- For literals, we can tell if the constraint error will be
5534 -- raised at compile time, so we never need a dynamic check, but
5535 -- if the exception will be raised, then post the usual warning,
5536 -- and replace the literal with a raise constraint error
5537 -- expression. As usual, skip this for access types
5539 elsif Compile_Time_Known_Value (Ck_Node)
5540 and then not Do_Access
5543 LB : constant Node_Id := Type_Low_Bound (T_Typ);
5544 UB : constant Node_Id := Type_High_Bound (T_Typ);
5546 Out_Of_Range : Boolean;
5547 Static_Bounds : constant Boolean :=
5548 Compile_Time_Known_Value (LB)
5549 and Compile_Time_Known_Value (UB);
5552 -- Following range tests should use Sem_Eval routine ???
5554 if Static_Bounds then
5555 if Is_Floating_Point_Type (S_Typ) then
5557 (Expr_Value_R (Ck_Node) < Expr_Value_R (LB))
5559 (Expr_Value_R (Ck_Node) > Expr_Value_R (UB));
5561 else -- fixed or discrete type
5563 Expr_Value (Ck_Node) < Expr_Value (LB)
5565 Expr_Value (Ck_Node) > Expr_Value (UB);
5568 -- Bounds of the type are static and the literal is
5569 -- out of range so make a warning message.
5571 if Out_Of_Range then
5572 if No (Warn_Node) then
5574 (Compile_Time_Constraint_Error
5576 "static value out of range of}?", T_Typ));
5580 (Compile_Time_Constraint_Error
5582 "static value out of range of}?", T_Typ));
5587 Cond := Discrete_Expr_Cond (Ck_Node, T_Typ);
5591 -- Here for the case of a non-static expression, we need a runtime
5592 -- check unless the source type range is guaranteed to be in the
5593 -- range of the target type.
5596 if not In_Subrange_Of (S_Typ, T_Typ) then
5597 Cond := Discrete_Expr_Cond (Ck_Node, T_Typ);
5602 if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then
5603 if Is_Constrained (T_Typ) then
5605 Expr_Actual := Get_Referenced_Object (Ck_Node);
5606 Exptyp := Get_Actual_Subtype (Expr_Actual);
5608 if Is_Access_Type (Exptyp) then
5609 Exptyp := Designated_Type (Exptyp);
5612 -- String_Literal case. This needs to be handled specially be-
5613 -- cause no index types are available for string literals. The
5614 -- condition is simply:
5616 -- T_Typ'Length = string-literal-length
5618 if Nkind (Expr_Actual) = N_String_Literal then
5621 -- General array case. Here we have a usable actual subtype for
5622 -- the expression, and the condition is built from the two types
5624 -- T_Typ'First < Exptyp'First or else
5625 -- T_Typ'Last > Exptyp'Last or else
5626 -- T_Typ'First(1) < Exptyp'First(1) or else
5627 -- T_Typ'Last(1) > Exptyp'Last(1) or else
5630 elsif Is_Constrained (Exptyp) then
5632 Ndims : constant Nat := Number_Dimensions (T_Typ);
5642 L_Index := First_Index (T_Typ);
5643 R_Index := First_Index (Exptyp);
5645 for Indx in 1 .. Ndims loop
5646 if not (Nkind (L_Index) = N_Raise_Constraint_Error
5648 Nkind (R_Index) = N_Raise_Constraint_Error)
5650 Get_Index_Bounds (L_Index, L_Low, L_High);
5651 Get_Index_Bounds (R_Index, R_Low, R_High);
5653 -- Deal with compile time length check. Note that we
5654 -- skip this in the access case, because the access
5655 -- value may be null, so we cannot know statically.
5658 Subtypes_Statically_Match
5659 (Etype (L_Index), Etype (R_Index))
5661 -- If the target type is constrained then we
5662 -- have to check for exact equality of bounds
5663 -- (required for qualified expressions).
5665 if Is_Constrained (T_Typ) then
5668 Range_Equal_E_Cond (Exptyp, T_Typ, Indx));
5672 (Cond, Range_E_Cond (Exptyp, T_Typ, Indx));
5683 -- Handle cases where we do not get a usable actual subtype that
5684 -- is constrained. This happens for example in the function call
5685 -- and explicit dereference cases. In these cases, we have to get
5686 -- the length or range from the expression itself, making sure we
5687 -- do not evaluate it more than once.
5689 -- Here Ck_Node is the original expression, or more properly the
5690 -- result of applying Duplicate_Expr to the original tree,
5691 -- forcing the result to be a name.
5695 Ndims : constant Nat := Number_Dimensions (T_Typ);
5698 -- Build the condition for the explicit dereference case
5700 for Indx in 1 .. Ndims loop
5702 (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx));
5709 -- Generate an Action to check that the bounds of the
5710 -- source value are within the constraints imposed by the
5711 -- target type for a conversion to an unconstrained type.
5714 if Nkind (Parent (Ck_Node)) = N_Type_Conversion then
5716 Opnd_Index : Node_Id;
5717 Targ_Index : Node_Id;
5721 := First_Index (Get_Actual_Subtype (Ck_Node));
5722 Targ_Index := First_Index (T_Typ);
5724 while Opnd_Index /= Empty loop
5725 if Nkind (Opnd_Index) = N_Range then
5727 (Low_Bound (Opnd_Index), Etype (Targ_Index))
5730 (High_Bound (Opnd_Index), Etype (Targ_Index))
5734 -- If null range, no check needed.
5736 Compile_Time_Known_Value (High_Bound (Opnd_Index))
5738 Compile_Time_Known_Value (Low_Bound (Opnd_Index))
5740 Expr_Value (High_Bound (Opnd_Index)) <
5741 Expr_Value (Low_Bound (Opnd_Index))
5745 elsif Is_Out_Of_Range
5746 (Low_Bound (Opnd_Index), Etype (Targ_Index))
5749 (High_Bound (Opnd_Index), Etype (Targ_Index))
5752 (Compile_Time_Constraint_Error
5753 (Wnode, "value out of range of}?", T_Typ));
5759 (Opnd_Index, Etype (Targ_Index)));
5763 Next_Index (Opnd_Index);
5764 Next_Index (Targ_Index);
5771 -- Construct the test and insert into the tree
5773 if Present (Cond) then
5775 Cond := Guard_Access (Cond, Loc, Ck_Node);
5779 (Make_Raise_Constraint_Error (Loc,
5781 Reason => CE_Range_Check_Failed));
5785 end Selected_Range_Checks;
5787 -------------------------------
5788 -- Storage_Checks_Suppressed --
5789 -------------------------------
5791 function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is
5793 if Present (E) and then Checks_May_Be_Suppressed (E) then
5794 return Is_Check_Suppressed (E, Storage_Check);
5796 return Scope_Suppress (Storage_Check);
5798 end Storage_Checks_Suppressed;
5800 ---------------------------
5801 -- Tag_Checks_Suppressed --
5802 ---------------------------
5804 function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is
5807 if Kill_Tag_Checks (E) then
5809 elsif Checks_May_Be_Suppressed (E) then
5810 return Is_Check_Suppressed (E, Tag_Check);
5814 return Scope_Suppress (Tag_Check);
5815 end Tag_Checks_Suppressed;