1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2007, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree
; use Atree
;
27 with Debug
; use Debug
;
28 with Einfo
; use Einfo
;
29 with Errout
; use Errout
;
30 with Exp_Ch2
; use Exp_Ch2
;
31 with Exp_Ch11
; use Exp_Ch11
;
32 with Exp_Pakd
; use Exp_Pakd
;
33 with Exp_Util
; use Exp_Util
;
34 with Elists
; use Elists
;
35 with Eval_Fat
; use Eval_Fat
;
36 with Freeze
; use Freeze
;
38 with Nlists
; use Nlists
;
39 with Nmake
; use Nmake
;
41 with Output
; use Output
;
42 with Restrict
; use Restrict
;
43 with Rident
; use Rident
;
44 with Rtsfind
; use Rtsfind
;
46 with Sem_Eval
; use Sem_Eval
;
47 with Sem_Ch3
; use Sem_Ch3
;
48 with Sem_Ch8
; use Sem_Ch8
;
49 with Sem_Res
; use Sem_Res
;
50 with Sem_Util
; use Sem_Util
;
51 with Sem_Warn
; use Sem_Warn
;
52 with Sinfo
; use Sinfo
;
53 with Sinput
; use Sinput
;
54 with Snames
; use Snames
;
55 with Sprint
; use Sprint
;
56 with Stand
; use Stand
;
57 with Targparm
; use Targparm
;
58 with Tbuild
; use Tbuild
;
59 with Ttypes
; use Ttypes
;
60 with Urealp
; use Urealp
;
61 with Validsw
; use Validsw
;
63 package body Checks
is
65 -- General note: many of these routines are concerned with generating
66 -- checking code to make sure that constraint error is raised at runtime.
67 -- Clearly this code is only needed if the expander is active, since
68 -- otherwise we will not be generating code or going into the runtime
71 -- We therefore disconnect most of these checks if the expander is
72 -- inactive. This has the additional benefit that we do not need to
73 -- worry about the tree being messed up by previous errors (since errors
74 -- turn off expansion anyway).
76 -- There are a few exceptions to the above rule. For instance routines
77 -- such as Apply_Scalar_Range_Check that do not insert any code can be
78 -- safely called even when the Expander is inactive (but Errors_Detected
79 -- is 0). The benefit of executing this code when expansion is off, is
80 -- the ability to emit constraint error warning for static expressions
81 -- even when we are not generating code.
83 -------------------------------------
84 -- Suppression of Redundant Checks --
85 -------------------------------------
87 -- This unit implements a limited circuit for removal of redundant
88 -- checks. The processing is based on a tracing of simple sequential
89 -- flow. For any sequence of statements, we save expressions that are
90 -- marked to be checked, and then if the same expression appears later
91 -- with the same check, then under certain circumstances, the second
92 -- check can be suppressed.
94 -- Basically, we can suppress the check if we know for certain that
95 -- the previous expression has been elaborated (together with its
96 -- check), and we know that the exception frame is the same, and that
97 -- nothing has happened to change the result of the exception.
99 -- Let us examine each of these three conditions in turn to describe
100 -- how we ensure that this condition is met.
102 -- First, we need to know for certain that the previous expression has
103 -- been executed. This is done principly by the mechanism of calling
104 -- Conditional_Statements_Begin at the start of any statement sequence
105 -- and Conditional_Statements_End at the end. The End call causes all
106 -- checks remembered since the Begin call to be discarded. This does
107 -- miss a few cases, notably the case of a nested BEGIN-END block with
108 -- no exception handlers. But the important thing is to be conservative.
109 -- The other protection is that all checks are discarded if a label
110 -- is encountered, since then the assumption of sequential execution
111 -- is violated, and we don't know enough about the flow.
113 -- Second, we need to know that the exception frame is the same. We
114 -- do this by killing all remembered checks when we enter a new frame.
115 -- Again, that's over-conservative, but generally the cases we can help
116 -- with are pretty local anyway (like the body of a loop for example).
118 -- Third, we must be sure to forget any checks which are no longer valid.
119 -- This is done by two mechanisms, first the Kill_Checks_Variable call is
120 -- used to note any changes to local variables. We only attempt to deal
121 -- with checks involving local variables, so we do not need to worry
122 -- about global variables. Second, a call to any non-global procedure
123 -- causes us to abandon all stored checks, since such a all may affect
124 -- the values of any local variables.
126 -- The following define the data structures used to deal with remembering
127 -- checks so that redundant checks can be eliminated as described above.
129 -- Right now, the only expressions that we deal with are of the form of
130 -- simple local objects (either declared locally, or IN parameters) or
131 -- such objects plus/minus a compile time known constant. We can do
132 -- more later on if it seems worthwhile, but this catches many simple
133 -- cases in practice.
135 -- The following record type reflects a single saved check. An entry
136 -- is made in the stack of saved checks if and only if the expression
137 -- has been elaborated with the indicated checks.
139 type Saved_Check
is record
141 -- Set True if entry is killed by Kill_Checks
144 -- The entity involved in the expression that is checked
147 -- A compile time value indicating the result of adding or
148 -- subtracting a compile time value. This value is to be
149 -- added to the value of the Entity. A value of zero is
150 -- used for the case of a simple entity reference.
152 Check_Type
: Character;
153 -- This is set to 'R' for a range check (in which case Target_Type
154 -- is set to the target type for the range check) or to 'O' for an
155 -- overflow check (in which case Target_Type is set to Empty).
157 Target_Type
: Entity_Id
;
158 -- Used only if Do_Range_Check is set. Records the target type for
159 -- the check. We need this, because a check is a duplicate only if
160 -- it has a the same target type (or more accurately one with a
161 -- range that is smaller or equal to the stored target type of a
165 -- The following table keeps track of saved checks. Rather than use an
166 -- extensible table. We just use a table of fixed size, and we discard
167 -- any saved checks that do not fit. That's very unlikely to happen and
168 -- this is only an optimization in any case.
170 Saved_Checks
: array (Int
range 1 .. 200) of Saved_Check
;
171 -- Array of saved checks
173 Num_Saved_Checks
: Nat
:= 0;
174 -- Number of saved checks
176 -- The following stack keeps track of statement ranges. It is treated
177 -- as a stack. When Conditional_Statements_Begin is called, an entry
178 -- is pushed onto this stack containing the value of Num_Saved_Checks
179 -- at the time of the call. Then when Conditional_Statements_End is
180 -- called, this value is popped off and used to reset Num_Saved_Checks.
182 -- Note: again, this is a fixed length stack with a size that should
183 -- always be fine. If the value of the stack pointer goes above the
184 -- limit, then we just forget all saved checks.
186 Saved_Checks_Stack
: array (Int
range 1 .. 100) of Nat
;
187 Saved_Checks_TOS
: Nat
:= 0;
189 -----------------------
190 -- Local Subprograms --
191 -----------------------
193 procedure Apply_Float_Conversion_Check
195 Target_Typ
: Entity_Id
);
196 -- The checks on a conversion from a floating-point type to an integer
197 -- type are delicate. They have to be performed before conversion, they
198 -- have to raise an exception when the operand is a NaN, and rounding must
199 -- be taken into account to determine the safe bounds of the operand.
201 procedure Apply_Selected_Length_Checks
203 Target_Typ
: Entity_Id
;
204 Source_Typ
: Entity_Id
;
205 Do_Static
: Boolean);
206 -- This is the subprogram that does all the work for Apply_Length_Check
207 -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as
208 -- described for the above routines. The Do_Static flag indicates that
209 -- only a static check is to be done.
211 procedure Apply_Selected_Range_Checks
213 Target_Typ
: Entity_Id
;
214 Source_Typ
: Entity_Id
;
215 Do_Static
: Boolean);
216 -- This is the subprogram that does all the work for Apply_Range_Check.
217 -- Expr, Target_Typ and Source_Typ are as described for the above
218 -- routine. The Do_Static flag indicates that only a static check is
221 type Check_Type
is new Check_Id
range Access_Check
.. Division_Check
;
222 function Check_Needed
(Nod
: Node_Id
; Check
: Check_Type
) return Boolean;
223 -- This function is used to see if an access or division by zero check is
224 -- needed. The check is to be applied to a single variable appearing in the
225 -- source, and N is the node for the reference. If N is not of this form,
226 -- True is returned with no further processing. If N is of the right form,
227 -- then further processing determines if the given Check is needed.
229 -- The particular circuit is to see if we have the case of a check that is
230 -- not needed because it appears in the right operand of a short circuited
231 -- conditional where the left operand guards the check. For example:
233 -- if Var = 0 or else Q / Var > 12 then
237 -- In this example, the division check is not required. At the same time
238 -- we can issue warnings for suspicious use of non-short-circuited forms,
241 -- if Var = 0 or Q / Var > 12 then
247 Check_Type
: Character;
248 Target_Type
: Entity_Id
;
249 Entry_OK
: out Boolean;
253 -- This routine is used by Enable_Range_Check and Enable_Overflow_Check
254 -- to see if a check is of the form for optimization, and if so, to see
255 -- if it has already been performed. Expr is the expression to check,
256 -- and Check_Type is 'R' for a range check, 'O' for an overflow check.
257 -- Target_Type is the target type for a range check, and Empty for an
258 -- overflow check. If the entry is not of the form for optimization,
259 -- then Entry_OK is set to False, and the remaining out parameters
260 -- are undefined. If the entry is OK, then Ent/Ofs are set to the
261 -- entity and offset from the expression. Check_Num is the number of
262 -- a matching saved entry in Saved_Checks, or zero if no such entry
265 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
;
266 -- If a discriminal is used in constraining a prival, Return reference
267 -- to the discriminal of the protected body (which renames the parameter
268 -- of the enclosing protected operation). This clumsy transformation is
269 -- needed because privals are created too late and their actual subtypes
270 -- are not available when analysing the bodies of the protected operations.
271 -- This function is called whenever the bound is an entity and the scope
272 -- indicates a protected operation. If the bound is an in-parameter of
273 -- a protected operation that is not a prival, the function returns the
275 -- To be cleaned up???
277 function Guard_Access
280 Ck_Node
: Node_Id
) return Node_Id
;
281 -- In the access type case, guard the test with a test to ensure
282 -- that the access value is non-null, since the checks do not
283 -- not apply to null access values.
285 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
);
286 -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the
287 -- Constraint_Error node.
289 function Range_Or_Validity_Checks_Suppressed
290 (Expr
: Node_Id
) return Boolean;
291 -- Returns True if either range or validity checks or both are suppressed
292 -- for the type of the given expression, or, if the expression is the name
293 -- of an entity, if these checks are suppressed for the entity.
295 function Selected_Length_Checks
297 Target_Typ
: Entity_Id
;
298 Source_Typ
: Entity_Id
;
299 Warn_Node
: Node_Id
) return Check_Result
;
300 -- Like Apply_Selected_Length_Checks, except it doesn't modify
301 -- anything, just returns a list of nodes as described in the spec of
302 -- this package for the Range_Check function.
304 function Selected_Range_Checks
306 Target_Typ
: Entity_Id
;
307 Source_Typ
: Entity_Id
;
308 Warn_Node
: Node_Id
) return Check_Result
;
309 -- Like Apply_Selected_Range_Checks, except it doesn't modify anything,
310 -- just returns a list of nodes as described in the spec of this package
311 -- for the Range_Check function.
313 ------------------------------
314 -- Access_Checks_Suppressed --
315 ------------------------------
317 function Access_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
319 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
320 return Is_Check_Suppressed
(E
, Access_Check
);
322 return Scope_Suppress
(Access_Check
);
324 end Access_Checks_Suppressed
;
326 -------------------------------------
327 -- Accessibility_Checks_Suppressed --
328 -------------------------------------
330 function Accessibility_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
332 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
333 return Is_Check_Suppressed
(E
, Accessibility_Check
);
335 return Scope_Suppress
(Accessibility_Check
);
337 end Accessibility_Checks_Suppressed
;
339 -----------------------------
340 -- Activate_Division_Check --
341 -----------------------------
343 procedure Activate_Division_Check
(N
: Node_Id
) is
345 Set_Do_Division_Check
(N
, True);
346 Possible_Local_Raise
(N
, Standard_Constraint_Error
);
347 end Activate_Division_Check
;
349 -----------------------------
350 -- Activate_Overflow_Check --
351 -----------------------------
353 procedure Activate_Overflow_Check
(N
: Node_Id
) is
355 Set_Do_Overflow_Check
(N
, True);
356 Possible_Local_Raise
(N
, Standard_Constraint_Error
);
357 end Activate_Overflow_Check
;
359 --------------------------
360 -- Activate_Range_Check --
361 --------------------------
363 procedure Activate_Range_Check
(N
: Node_Id
) is
365 Set_Do_Range_Check
(N
, True);
366 Possible_Local_Raise
(N
, Standard_Constraint_Error
);
367 end Activate_Range_Check
;
369 ---------------------------------
370 -- Alignment_Checks_Suppressed --
371 ---------------------------------
373 function Alignment_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
375 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
376 return Is_Check_Suppressed
(E
, Alignment_Check
);
378 return Scope_Suppress
(Alignment_Check
);
380 end Alignment_Checks_Suppressed
;
382 -------------------------
383 -- Append_Range_Checks --
384 -------------------------
386 procedure Append_Range_Checks
387 (Checks
: Check_Result
;
389 Suppress_Typ
: Entity_Id
;
390 Static_Sloc
: Source_Ptr
;
393 Internal_Flag_Node
: constant Node_Id
:= Flag_Node
;
394 Internal_Static_Sloc
: constant Source_Ptr
:= Static_Sloc
;
396 Checks_On
: constant Boolean :=
397 (not Index_Checks_Suppressed
(Suppress_Typ
))
399 (not Range_Checks_Suppressed
(Suppress_Typ
));
402 -- For now we just return if Checks_On is false, however this should
403 -- be enhanced to check for an always True value in the condition
404 -- and to generate a compilation warning???
406 if not Checks_On
then
411 exit when No
(Checks
(J
));
413 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
414 and then Present
(Condition
(Checks
(J
)))
416 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
417 Append_To
(Stmts
, Checks
(J
));
418 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
424 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
425 Reason
=> CE_Range_Check_Failed
));
428 end Append_Range_Checks
;
430 ------------------------
431 -- Apply_Access_Check --
432 ------------------------
434 procedure Apply_Access_Check
(N
: Node_Id
) is
435 P
: constant Node_Id
:= Prefix
(N
);
438 -- We do not need checks if we are not generating code (i.e. the
439 -- expander is not active). This is not just an optimization, there
440 -- are cases (e.g. with pragma Debug) where generating the checks
441 -- can cause real trouble).
443 if not Expander_Active
then
447 -- No check if short circuiting makes check unnecessary
449 if not Check_Needed
(P
, Access_Check
) then
453 -- Otherwise go ahead and install the check
455 Install_Null_Excluding_Check
(P
);
456 end Apply_Access_Check
;
458 -------------------------------
459 -- Apply_Accessibility_Check --
460 -------------------------------
462 procedure Apply_Accessibility_Check
(N
: Node_Id
; Typ
: Entity_Id
) is
463 Loc
: constant Source_Ptr
:= Sloc
(N
);
464 Param_Ent
: constant Entity_Id
:= Param_Entity
(N
);
465 Param_Level
: Node_Id
;
466 Type_Level
: Node_Id
;
469 if Inside_A_Generic
then
472 -- Only apply the run-time check if the access parameter
473 -- has an associated extra access level parameter and
474 -- when the level of the type is less deep than the level
475 -- of the access parameter.
477 elsif Present
(Param_Ent
)
478 and then Present
(Extra_Accessibility
(Param_Ent
))
479 and then UI_Gt
(Object_Access_Level
(N
),
480 Type_Access_Level
(Typ
))
481 and then not Accessibility_Checks_Suppressed
(Param_Ent
)
482 and then not Accessibility_Checks_Suppressed
(Typ
)
485 New_Occurrence_Of
(Extra_Accessibility
(Param_Ent
), Loc
);
488 Make_Integer_Literal
(Loc
, Type_Access_Level
(Typ
));
490 -- Raise Program_Error if the accessibility level of the the access
491 -- parameter is deeper than the level of the target access type.
494 Make_Raise_Program_Error
(Loc
,
497 Left_Opnd
=> Param_Level
,
498 Right_Opnd
=> Type_Level
),
499 Reason
=> PE_Accessibility_Check_Failed
));
501 Analyze_And_Resolve
(N
);
503 end Apply_Accessibility_Check
;
505 --------------------------------
506 -- Apply_Address_Clause_Check --
507 --------------------------------
509 procedure Apply_Address_Clause_Check
(E
: Entity_Id
; N
: Node_Id
) is
510 AC
: constant Node_Id
:= Address_Clause
(E
);
511 Loc
: constant Source_Ptr
:= Sloc
(AC
);
512 Typ
: constant Entity_Id
:= Etype
(E
);
513 Aexp
: constant Node_Id
:= Expression
(AC
);
516 -- Address expression (not necessarily the same as Aexp, for example
517 -- when Aexp is a reference to a constant, in which case Expr gets
518 -- reset to reference the value expression of the constant.
520 Size_Warning_Output
: Boolean := False;
521 -- If we output a size warning we set this True, to stop generating
522 -- what is likely to be an unuseful redundant alignment warning.
524 procedure Compile_Time_Bad_Alignment
;
525 -- Post error warnings when alignment is known to be incompatible. Note
526 -- that we do not go as far as inserting a raise of Program_Error since
527 -- this is an erroneous case, and it may happen that we are lucky and an
528 -- underaligned address turns out to be OK after all. Also this warning
529 -- is suppressed if we already complained about the size.
531 --------------------------------
532 -- Compile_Time_Bad_Alignment --
533 --------------------------------
535 procedure Compile_Time_Bad_Alignment
is
537 if not Size_Warning_Output
538 and then Address_Clause_Overlay_Warnings
541 ("?specified address for& may be inconsistent with alignment ",
544 ("\?program execution may be erroneous (RM 13.3(27))",
546 Set_Address_Warning_Posted
(AC
);
548 end Compile_Time_Bad_Alignment
;
550 -- Start of processing for Apply_Address_Clause_Check
553 -- First obtain expression from address clause
555 Expr
:= Expression
(AC
);
557 -- The following loop digs for the real expression to use in the check
560 -- For constant, get constant expression
562 if Is_Entity_Name
(Expr
)
563 and then Ekind
(Entity
(Expr
)) = E_Constant
565 Expr
:= Constant_Value
(Entity
(Expr
));
567 -- For unchecked conversion, get result to convert
569 elsif Nkind
(Expr
) = N_Unchecked_Type_Conversion
then
570 Expr
:= Expression
(Expr
);
572 -- For (common case) of To_Address call, get argument
574 elsif Nkind
(Expr
) = N_Function_Call
575 and then Is_Entity_Name
(Name
(Expr
))
576 and then Is_RTE
(Entity
(Name
(Expr
)), RE_To_Address
)
578 Expr
:= First
(Parameter_Associations
(Expr
));
580 if Nkind
(Expr
) = N_Parameter_Association
then
581 Expr
:= Explicit_Actual_Parameter
(Expr
);
584 -- We finally have the real expression
591 -- Output a warning if we have the situation of
593 -- for X'Address use Y'Address
595 -- and X and Y both have known object sizes, and Y is smaller than X
597 if Nkind
(Expr
) = N_Attribute_Reference
598 and then Attribute_Name
(Expr
) = Name_Address
599 and then Is_Entity_Name
(Prefix
(Expr
))
602 Exp_Ent
: constant Entity_Id
:= Entity
(Prefix
(Expr
));
603 Obj_Size
: Uint
:= No_Uint
;
604 Exp_Size
: Uint
:= No_Uint
;
607 if Known_Esize
(E
) then
608 Obj_Size
:= Esize
(E
);
609 elsif Known_Esize
(Etype
(E
)) then
610 Obj_Size
:= Esize
(Etype
(E
));
613 if Known_Esize
(Exp_Ent
) then
614 Exp_Size
:= Esize
(Exp_Ent
);
615 elsif Known_Esize
(Etype
(Exp_Ent
)) then
616 Exp_Size
:= Esize
(Etype
(Exp_Ent
));
619 if Obj_Size
/= No_Uint
620 and then Exp_Size
/= No_Uint
621 and then Obj_Size
> Exp_Size
622 and then not Warnings_Off
(E
)
624 if Address_Clause_Overlay_Warnings
then
626 ("?& overlays smaller object", Aexp
, E
);
628 ("\?program execution may be erroneous", Aexp
, E
);
629 Size_Warning_Output
:= True;
630 Set_Address_Warning_Posted
(AC
);
636 -- See if alignment check needed. Note that we never need a check if the
637 -- maximum alignment is one, since the check will always succeed.
639 -- Note: we do not check for checks suppressed here, since that check
640 -- was done in Sem_Ch13 when the address clause was processed. We are
641 -- only called if checks were not suppressed. The reason for this is
642 -- that we have to delay the call to Apply_Alignment_Check till freeze
643 -- time (so that all types etc are elaborated), but we have to check
644 -- the status of check suppressing at the point of the address clause.
647 or else not Check_Address_Alignment
(AC
)
648 or else Maximum_Alignment
= 1
653 -- See if we know that Expr is a bad alignment at compile time
655 if Compile_Time_Known_Value
(Expr
)
656 and then (Known_Alignment
(E
) or else Known_Alignment
(Typ
))
659 AL
: Uint
:= Alignment
(Typ
);
662 -- The object alignment might be more restrictive than the
665 if Known_Alignment
(E
) then
669 if Expr_Value
(Expr
) mod AL
/= 0 then
670 Compile_Time_Bad_Alignment
;
676 -- If the expression has the form X'Address, then we can find out if
677 -- the object X has an alignment that is compatible with the object E.
679 elsif Nkind
(Expr
) = N_Attribute_Reference
680 and then Attribute_Name
(Expr
) = Name_Address
683 AR
: constant Alignment_Result
:=
684 Has_Compatible_Alignment
(E
, Prefix
(Expr
));
686 if AR
= Known_Compatible
then
688 elsif AR
= Known_Incompatible
then
689 Compile_Time_Bad_Alignment
;
694 -- Here we do not know if the value is acceptable. Stricly we don't have
695 -- to do anything, since if the alignment is bad, we have an erroneous
696 -- program. However we are allowed to check for erroneous conditions and
697 -- we decide to do this by default if the check is not suppressed.
699 -- However, don't do the check if elaboration code is unwanted
701 if Restriction_Active
(No_Elaboration_Code
) then
704 -- Generate a check to raise PE if alignment may be inappropriate
707 -- If the original expression is a non-static constant, use the
708 -- name of the constant itself rather than duplicating its
709 -- defining expression, which was extracted above.
711 -- Note: Expr is empty if the address-clause is applied to in-mode
712 -- actuals (allowed by 13.1(22)).
714 if not Present
(Expr
)
716 (Is_Entity_Name
(Expression
(AC
))
717 and then Ekind
(Entity
(Expression
(AC
))) = E_Constant
718 and then Nkind
(Parent
(Entity
(Expression
(AC
))))
719 = N_Object_Declaration
)
721 Expr
:= New_Copy_Tree
(Expression
(AC
));
723 Remove_Side_Effects
(Expr
);
726 Insert_After_And_Analyze
(N
,
727 Make_Raise_Program_Error
(Loc
,
734 (RTE
(RE_Integer_Address
), Expr
),
736 Make_Attribute_Reference
(Loc
,
737 Prefix
=> New_Occurrence_Of
(E
, Loc
),
738 Attribute_Name
=> Name_Alignment
)),
739 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
740 Reason
=> PE_Misaligned_Address_Value
),
741 Suppress
=> All_Checks
);
746 -- If we have some missing run time component in configurable run time
747 -- mode then just skip the check (it is not required in any case).
749 when RE_Not_Available
=>
751 end Apply_Address_Clause_Check
;
753 -------------------------------------
754 -- Apply_Arithmetic_Overflow_Check --
755 -------------------------------------
757 -- This routine is called only if the type is an integer type, and
758 -- a software arithmetic overflow check must be performed for op
759 -- (add, subtract, multiply). The check is performed only if
760 -- Software_Overflow_Checking is enabled and Do_Overflow_Check
761 -- is set. In this case we expand the operation into a more complex
762 -- sequence of tests that ensures that overflow is properly caught.
764 procedure Apply_Arithmetic_Overflow_Check
(N
: Node_Id
) is
765 Loc
: constant Source_Ptr
:= Sloc
(N
);
766 Typ
: constant Entity_Id
:= Etype
(N
);
767 Rtyp
: constant Entity_Id
:= Root_Type
(Typ
);
768 Siz
: constant Int
:= UI_To_Int
(Esize
(Rtyp
));
769 Dsiz
: constant Int
:= Siz
* 2;
776 -- Skip this if overflow checks are done in back end, or the overflow
777 -- flag is not set anyway, or we are not doing code expansion.
778 -- Special case CLI target, where arithmetic overflow checks can be
779 -- performed for integer and long_integer
781 if Backend_Overflow_Checks_On_Target
782 or else (VM_Target
= CLI_Target
and then Siz
>= Standard_Integer_Size
)
783 or else not Do_Overflow_Check
(N
)
784 or else not Expander_Active
789 -- Otherwise, we generate the full general code for front end overflow
790 -- detection, which works by doing arithmetic in a larger type:
796 -- Typ (Checktyp (x) op Checktyp (y));
798 -- where Typ is the type of the original expression, and Checktyp is
799 -- an integer type of sufficient length to hold the largest possible
802 -- In the case where check type exceeds the size of Long_Long_Integer,
803 -- we use a different approach, expanding to:
805 -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y)))
807 -- where xxx is Add, Multiply or Subtract as appropriate
809 -- Find check type if one exists
811 if Dsiz
<= Standard_Integer_Size
then
812 Ctyp
:= Standard_Integer
;
814 elsif Dsiz
<= Standard_Long_Long_Integer_Size
then
815 Ctyp
:= Standard_Long_Long_Integer
;
817 -- No check type exists, use runtime call
820 if Nkind
(N
) = N_Op_Add
then
821 Cent
:= RE_Add_With_Ovflo_Check
;
823 elsif Nkind
(N
) = N_Op_Multiply
then
824 Cent
:= RE_Multiply_With_Ovflo_Check
;
827 pragma Assert
(Nkind
(N
) = N_Op_Subtract
);
828 Cent
:= RE_Subtract_With_Ovflo_Check
;
833 Make_Function_Call
(Loc
,
834 Name
=> New_Reference_To
(RTE
(Cent
), Loc
),
835 Parameter_Associations
=> New_List
(
836 OK_Convert_To
(RTE
(RE_Integer_64
), Left_Opnd
(N
)),
837 OK_Convert_To
(RTE
(RE_Integer_64
), Right_Opnd
(N
))))));
839 Analyze_And_Resolve
(N
, Typ
);
843 -- If we fall through, we have the case where we do the arithmetic in
844 -- the next higher type and get the check by conversion. In these cases
845 -- Ctyp is set to the type to be used as the check type.
847 Opnod
:= Relocate_Node
(N
);
849 Opnd
:= OK_Convert_To
(Ctyp
, Left_Opnd
(Opnod
));
852 Set_Etype
(Opnd
, Ctyp
);
853 Set_Analyzed
(Opnd
, True);
854 Set_Left_Opnd
(Opnod
, Opnd
);
856 Opnd
:= OK_Convert_To
(Ctyp
, Right_Opnd
(Opnod
));
859 Set_Etype
(Opnd
, Ctyp
);
860 Set_Analyzed
(Opnd
, True);
861 Set_Right_Opnd
(Opnod
, Opnd
);
863 -- The type of the operation changes to the base type of the check type,
864 -- and we reset the overflow check indication, since clearly no overflow
865 -- is possible now that we are using a double length type. We also set
866 -- the Analyzed flag to avoid a recursive attempt to expand the node.
868 Set_Etype
(Opnod
, Base_Type
(Ctyp
));
869 Set_Do_Overflow_Check
(Opnod
, False);
870 Set_Analyzed
(Opnod
, True);
872 -- Now build the outer conversion
874 Opnd
:= OK_Convert_To
(Typ
, Opnod
);
876 Set_Etype
(Opnd
, Typ
);
878 -- In the discrete type case, we directly generate the range check for
879 -- the outer operand. This range check will implement the required
882 if Is_Discrete_Type
(Typ
) then
884 Generate_Range_Check
(Expression
(N
), Typ
, CE_Overflow_Check_Failed
);
886 -- For other types, we enable overflow checking on the conversion,
887 -- after setting the node as analyzed to prevent recursive attempts
888 -- to expand the conversion node.
891 Set_Analyzed
(Opnd
, True);
892 Enable_Overflow_Check
(Opnd
);
897 when RE_Not_Available
=>
899 end Apply_Arithmetic_Overflow_Check
;
901 ----------------------------
902 -- Apply_Constraint_Check --
903 ----------------------------
905 procedure Apply_Constraint_Check
908 No_Sliding
: Boolean := False)
910 Desig_Typ
: Entity_Id
;
913 if Inside_A_Generic
then
916 elsif Is_Scalar_Type
(Typ
) then
917 Apply_Scalar_Range_Check
(N
, Typ
);
919 elsif Is_Array_Type
(Typ
) then
921 -- A useful optimization: an aggregate with only an others clause
922 -- always has the right bounds.
924 if Nkind
(N
) = N_Aggregate
925 and then No
(Expressions
(N
))
927 (First
(Choices
(First
(Component_Associations
(N
)))))
933 if Is_Constrained
(Typ
) then
934 Apply_Length_Check
(N
, Typ
);
937 Apply_Range_Check
(N
, Typ
);
940 Apply_Range_Check
(N
, Typ
);
943 elsif (Is_Record_Type
(Typ
)
944 or else Is_Private_Type
(Typ
))
945 and then Has_Discriminants
(Base_Type
(Typ
))
946 and then Is_Constrained
(Typ
)
948 Apply_Discriminant_Check
(N
, Typ
);
950 elsif Is_Access_Type
(Typ
) then
952 Desig_Typ
:= Designated_Type
(Typ
);
954 -- No checks necessary if expression statically null
956 if Known_Null
(N
) then
957 if Can_Never_Be_Null
(Typ
) then
958 Install_Null_Excluding_Check
(N
);
961 -- No sliding possible on access to arrays
963 elsif Is_Array_Type
(Desig_Typ
) then
964 if Is_Constrained
(Desig_Typ
) then
965 Apply_Length_Check
(N
, Typ
);
968 Apply_Range_Check
(N
, Typ
);
970 elsif Has_Discriminants
(Base_Type
(Desig_Typ
))
971 and then Is_Constrained
(Desig_Typ
)
973 Apply_Discriminant_Check
(N
, Typ
);
976 -- Apply the the 2005 Null_Excluding check. Note that we do not apply
977 -- this check if the constraint node is illegal, as shown by having
978 -- an error posted. This additional guard prevents cascaded errors
979 -- and compiler aborts on illegal programs involving Ada 2005 checks.
981 if Can_Never_Be_Null
(Typ
)
982 and then not Can_Never_Be_Null
(Etype
(N
))
983 and then not Error_Posted
(N
)
985 Install_Null_Excluding_Check
(N
);
988 end Apply_Constraint_Check
;
990 ------------------------------
991 -- Apply_Discriminant_Check --
992 ------------------------------
994 procedure Apply_Discriminant_Check
997 Lhs
: Node_Id
:= Empty
)
999 Loc
: constant Source_Ptr
:= Sloc
(N
);
1000 Do_Access
: constant Boolean := Is_Access_Type
(Typ
);
1001 S_Typ
: Entity_Id
:= Etype
(N
);
1005 function Is_Aliased_Unconstrained_Component
return Boolean;
1006 -- It is possible for an aliased component to have a nominal
1007 -- unconstrained subtype (through instantiation). If this is a
1008 -- discriminated component assigned in the expansion of an aggregate
1009 -- in an initialization, the check must be suppressed. This unusual
1010 -- situation requires a predicate of its own.
1012 ----------------------------------------
1013 -- Is_Aliased_Unconstrained_Component --
1014 ----------------------------------------
1016 function Is_Aliased_Unconstrained_Component
return Boolean is
1021 if Nkind
(Lhs
) /= N_Selected_Component
then
1024 Comp
:= Entity
(Selector_Name
(Lhs
));
1025 Pref
:= Prefix
(Lhs
);
1028 if Ekind
(Comp
) /= E_Component
1029 or else not Is_Aliased
(Comp
)
1034 return not Comes_From_Source
(Pref
)
1035 and then In_Instance
1036 and then not Is_Constrained
(Etype
(Comp
));
1037 end Is_Aliased_Unconstrained_Component
;
1039 -- Start of processing for Apply_Discriminant_Check
1043 T_Typ
:= Designated_Type
(Typ
);
1048 -- Nothing to do if discriminant checks are suppressed or else no code
1049 -- is to be generated
1051 if not Expander_Active
1052 or else Discriminant_Checks_Suppressed
(T_Typ
)
1057 -- No discriminant checks necessary for an access when expression is
1058 -- statically Null. This is not only an optimization, it is fundamental
1059 -- because otherwise discriminant checks may be generated in init procs
1060 -- for types containing an access to a not-yet-frozen record, causing a
1061 -- deadly forward reference.
1063 -- Also, if the expression is of an access type whose designated type is
1064 -- incomplete, then the access value must be null and we suppress the
1067 if Known_Null
(N
) then
1070 elsif Is_Access_Type
(S_Typ
) then
1071 S_Typ
:= Designated_Type
(S_Typ
);
1073 if Ekind
(S_Typ
) = E_Incomplete_Type
then
1078 -- If an assignment target is present, then we need to generate the
1079 -- actual subtype if the target is a parameter or aliased object with
1080 -- an unconstrained nominal subtype.
1082 -- Ada 2005 (AI-363): For Ada 2005, we limit the building of the actual
1083 -- subtype to the parameter and dereference cases, since other aliased
1084 -- objects are unconstrained (unless the nominal subtype is explicitly
1085 -- constrained). (But we also need to test for renamings???)
1088 and then (Present
(Param_Entity
(Lhs
))
1089 or else (Ada_Version
< Ada_05
1090 and then not Is_Constrained
(T_Typ
)
1091 and then Is_Aliased_View
(Lhs
)
1092 and then not Is_Aliased_Unconstrained_Component
)
1093 or else (Ada_Version
>= Ada_05
1094 and then not Is_Constrained
(T_Typ
)
1095 and then Nkind
(Lhs
) = N_Explicit_Dereference
1096 and then Nkind
(Original_Node
(Lhs
)) /=
1099 T_Typ
:= Get_Actual_Subtype
(Lhs
);
1102 -- Nothing to do if the type is unconstrained (this is the case where
1103 -- the actual subtype in the RM sense of N is unconstrained and no check
1106 if not Is_Constrained
(T_Typ
) then
1109 -- Ada 2005: nothing to do if the type is one for which there is a
1110 -- partial view that is constrained.
1112 elsif Ada_Version
>= Ada_05
1113 and then Has_Constrained_Partial_View
(Base_Type
(T_Typ
))
1118 -- Nothing to do if the type is an Unchecked_Union
1120 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
1124 -- Suppress checks if the subtypes are the same. the check must be
1125 -- preserved in an assignment to a formal, because the constraint is
1126 -- given by the actual.
1128 if Nkind
(Original_Node
(N
)) /= N_Allocator
1130 or else not Is_Entity_Name
(Lhs
)
1131 or else No
(Param_Entity
(Lhs
)))
1134 or else (Do_Access
and then Designated_Type
(Typ
) = S_Typ
))
1135 and then not Is_Aliased_View
(Lhs
)
1140 -- We can also eliminate checks on allocators with a subtype mark that
1141 -- coincides with the context type. The context type may be a subtype
1142 -- without a constraint (common case, a generic actual).
1144 elsif Nkind
(Original_Node
(N
)) = N_Allocator
1145 and then Is_Entity_Name
(Expression
(Original_Node
(N
)))
1148 Alloc_Typ
: constant Entity_Id
:=
1149 Entity
(Expression
(Original_Node
(N
)));
1152 if Alloc_Typ
= T_Typ
1153 or else (Nkind
(Parent
(T_Typ
)) = N_Subtype_Declaration
1154 and then Is_Entity_Name
(
1155 Subtype_Indication
(Parent
(T_Typ
)))
1156 and then Alloc_Typ
= Base_Type
(T_Typ
))
1164 -- See if we have a case where the types are both constrained, and all
1165 -- the constraints are constants. In this case, we can do the check
1166 -- successfully at compile time.
1168 -- We skip this check for the case where the node is a rewritten`
1169 -- allocator, because it already carries the context subtype, and
1170 -- extracting the discriminants from the aggregate is messy.
1172 if Is_Constrained
(S_Typ
)
1173 and then Nkind
(Original_Node
(N
)) /= N_Allocator
1183 -- S_Typ may not have discriminants in the case where it is a
1184 -- private type completed by a default discriminated type. In that
1185 -- case, we need to get the constraints from the underlying_type.
1186 -- If the underlying type is unconstrained (i.e. has no default
1187 -- discriminants) no check is needed.
1189 if Has_Discriminants
(S_Typ
) then
1190 Discr
:= First_Discriminant
(S_Typ
);
1191 DconS
:= First_Elmt
(Discriminant_Constraint
(S_Typ
));
1194 Discr
:= First_Discriminant
(Underlying_Type
(S_Typ
));
1197 (Discriminant_Constraint
(Underlying_Type
(S_Typ
)));
1203 -- A further optimization: if T_Typ is derived from S_Typ
1204 -- without imposing a constraint, no check is needed.
1206 if Nkind
(Original_Node
(Parent
(T_Typ
))) =
1207 N_Full_Type_Declaration
1210 Type_Def
: constant Node_Id
:=
1212 (Original_Node
(Parent
(T_Typ
)));
1214 if Nkind
(Type_Def
) = N_Derived_Type_Definition
1215 and then Is_Entity_Name
(Subtype_Indication
(Type_Def
))
1216 and then Entity
(Subtype_Indication
(Type_Def
)) = S_Typ
1224 DconT
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
1226 while Present
(Discr
) loop
1227 ItemS
:= Node
(DconS
);
1228 ItemT
:= Node
(DconT
);
1230 -- For a discriminated component type constrained by the
1231 -- current instance of an enclosing type, there is no
1232 -- applicable discriminant check.
1234 if Nkind
(ItemT
) = N_Attribute_Reference
1235 and then Is_Access_Type
(Etype
(ItemT
))
1236 and then Is_Entity_Name
(Prefix
(ItemT
))
1237 and then Is_Type
(Entity
(Prefix
(ItemT
)))
1243 not Is_OK_Static_Expression
(ItemS
)
1245 not Is_OK_Static_Expression
(ItemT
);
1247 if Expr_Value
(ItemS
) /= Expr_Value
(ItemT
) then
1248 if Do_Access
then -- needs run-time check.
1251 Apply_Compile_Time_Constraint_Error
1252 (N
, "incorrect value for discriminant&?",
1253 CE_Discriminant_Check_Failed
, Ent
=> Discr
);
1260 Next_Discriminant
(Discr
);
1269 -- Here we need a discriminant check. First build the expression
1270 -- for the comparisons of the discriminants:
1272 -- (n.disc1 /= typ.disc1) or else
1273 -- (n.disc2 /= typ.disc2) or else
1275 -- (n.discn /= typ.discn)
1277 Cond
:= Build_Discriminant_Checks
(N
, T_Typ
);
1279 -- If Lhs is set and is a parameter, then the condition is
1280 -- guarded by: lhs'constrained and then (condition built above)
1282 if Present
(Param_Entity
(Lhs
)) then
1286 Make_Attribute_Reference
(Loc
,
1287 Prefix
=> New_Occurrence_Of
(Param_Entity
(Lhs
), Loc
),
1288 Attribute_Name
=> Name_Constrained
),
1289 Right_Opnd
=> Cond
);
1293 Cond
:= Guard_Access
(Cond
, Loc
, N
);
1297 Make_Raise_Constraint_Error
(Loc
,
1299 Reason
=> CE_Discriminant_Check_Failed
));
1300 end Apply_Discriminant_Check
;
1302 ------------------------
1303 -- Apply_Divide_Check --
1304 ------------------------
1306 procedure Apply_Divide_Check
(N
: Node_Id
) is
1307 Loc
: constant Source_Ptr
:= Sloc
(N
);
1308 Typ
: constant Entity_Id
:= Etype
(N
);
1309 Left
: constant Node_Id
:= Left_Opnd
(N
);
1310 Right
: constant Node_Id
:= Right_Opnd
(N
);
1322 and then not Backend_Divide_Checks_On_Target
1323 and then Check_Needed
(Right
, Division_Check
)
1325 Determine_Range
(Right
, ROK
, Rlo
, Rhi
);
1327 -- See if division by zero possible, and if so generate test. This
1328 -- part of the test is not controlled by the -gnato switch.
1330 if Do_Division_Check
(N
) then
1331 if (not ROK
) or else (Rlo
<= 0 and then 0 <= Rhi
) then
1333 Make_Raise_Constraint_Error
(Loc
,
1336 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(Right
),
1337 Right_Opnd
=> Make_Integer_Literal
(Loc
, 0)),
1338 Reason
=> CE_Divide_By_Zero
));
1342 -- Test for extremely annoying case of xxx'First divided by -1
1344 if Do_Overflow_Check
(N
) then
1345 if Nkind
(N
) = N_Op_Divide
1346 and then Is_Signed_Integer_Type
(Typ
)
1348 Determine_Range
(Left
, LOK
, Llo
, Lhi
);
1349 LLB
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
1351 if ((not ROK
) or else (Rlo
<= (-1) and then (-1) <= Rhi
))
1353 ((not LOK
) or else (Llo
= LLB
))
1356 Make_Raise_Constraint_Error
(Loc
,
1362 Duplicate_Subexpr_Move_Checks
(Left
),
1363 Right_Opnd
=> Make_Integer_Literal
(Loc
, LLB
)),
1367 Duplicate_Subexpr
(Right
),
1369 Make_Integer_Literal
(Loc
, -1))),
1370 Reason
=> CE_Overflow_Check_Failed
));
1375 end Apply_Divide_Check
;
1377 ----------------------------------
1378 -- Apply_Float_Conversion_Check --
1379 ----------------------------------
1381 -- Let F and I be the source and target types of the conversion. The RM
1382 -- specifies that a floating-point value X is rounded to the nearest
1383 -- integer, with halfway cases being rounded away from zero. The rounded
1384 -- value of X is checked against I'Range.
1386 -- The catch in the above paragraph is that there is no good way to know
1387 -- whether the round-to-integer operation resulted in overflow. A remedy is
1388 -- to perform a range check in the floating-point domain instead, however:
1390 -- (1) The bounds may not be known at compile time
1391 -- (2) The check must take into account rounding or truncation.
1392 -- (3) The range of type I may not be exactly representable in F.
1393 -- (4) For the rounding case, The end-points I'First - 0.5 and
1394 -- I'Last + 0.5 may or may not be in range, depending on the
1395 -- sign of I'First and I'Last.
1396 -- (5) X may be a NaN, which will fail any comparison
1398 -- The following steps correctly convert X with rounding:
1400 -- (1) If either I'First or I'Last is not known at compile time, use
1401 -- I'Base instead of I in the next three steps and perform a
1402 -- regular range check against I'Range after conversion.
1403 -- (2) If I'First - 0.5 is representable in F then let Lo be that
1404 -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be
1405 -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First).
1406 -- In other words, take one of the closest floating-point numbers
1407 -- (which is an integer value) to I'First, and see if it is in
1409 -- (3) If I'Last + 0.5 is representable in F then let Hi be that value
1410 -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be
1411 -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last).
1412 -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo)
1413 -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi)
1415 -- For the truncating case, replace steps (2) and (3) as follows:
1416 -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK
1417 -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let
1419 -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK
1420 -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let
1423 procedure Apply_Float_Conversion_Check
1425 Target_Typ
: Entity_Id
)
1427 LB
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1428 HB
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1429 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1430 Expr_Type
: constant Entity_Id
:= Base_Type
(Etype
(Ck_Node
));
1431 Target_Base
: constant Entity_Id
:=
1432 Implementation_Base_Type
(Target_Typ
);
1434 Par
: constant Node_Id
:= Parent
(Ck_Node
);
1435 pragma Assert
(Nkind
(Par
) = N_Type_Conversion
);
1436 -- Parent of check node, must be a type conversion
1438 Truncate
: constant Boolean := Float_Truncate
(Par
);
1439 Max_Bound
: constant Uint
:=
1441 (Machine_Radix
(Expr_Type
),
1442 Machine_Mantissa
(Expr_Type
) - 1) - 1;
1444 -- Largest bound, so bound plus or minus half is a machine number of F
1446 Ifirst
, Ilast
: Uint
;
1447 -- Bounds of integer type
1450 -- Bounds to check in floating-point domain
1452 Lo_OK
, Hi_OK
: Boolean;
1453 -- True iff Lo resp. Hi belongs to I'Range
1455 Lo_Chk
, Hi_Chk
: Node_Id
;
1456 -- Expressions that are False iff check fails
1458 Reason
: RT_Exception_Code
;
1461 if not Compile_Time_Known_Value
(LB
)
1462 or not Compile_Time_Known_Value
(HB
)
1465 -- First check that the value falls in the range of the base type,
1466 -- to prevent overflow during conversion and then perform a
1467 -- regular range check against the (dynamic) bounds.
1469 pragma Assert
(Target_Base
/= Target_Typ
);
1471 Temp
: constant Entity_Id
:=
1472 Make_Defining_Identifier
(Loc
,
1473 Chars
=> New_Internal_Name
('T'));
1476 Apply_Float_Conversion_Check
(Ck_Node
, Target_Base
);
1477 Set_Etype
(Temp
, Target_Base
);
1479 Insert_Action
(Parent
(Par
),
1480 Make_Object_Declaration
(Loc
,
1481 Defining_Identifier
=> Temp
,
1482 Object_Definition
=> New_Occurrence_Of
(Target_Typ
, Loc
),
1483 Expression
=> New_Copy_Tree
(Par
)),
1484 Suppress
=> All_Checks
);
1487 Make_Raise_Constraint_Error
(Loc
,
1490 Left_Opnd
=> New_Occurrence_Of
(Temp
, Loc
),
1491 Right_Opnd
=> New_Occurrence_Of
(Target_Typ
, Loc
)),
1492 Reason
=> CE_Range_Check_Failed
));
1493 Rewrite
(Par
, New_Occurrence_Of
(Temp
, Loc
));
1499 -- Get the bounds of the target type
1501 Ifirst
:= Expr_Value
(LB
);
1502 Ilast
:= Expr_Value
(HB
);
1504 -- Check against lower bound
1506 if Truncate
and then Ifirst
> 0 then
1507 Lo
:= Pred
(Expr_Type
, UR_From_Uint
(Ifirst
));
1511 Lo
:= Succ
(Expr_Type
, UR_From_Uint
(Ifirst
- 1));
1514 elsif abs (Ifirst
) < Max_Bound
then
1515 Lo
:= UR_From_Uint
(Ifirst
) - Ureal_Half
;
1516 Lo_OK
:= (Ifirst
> 0);
1519 Lo
:= Machine
(Expr_Type
, UR_From_Uint
(Ifirst
), Round_Even
, Ck_Node
);
1520 Lo_OK
:= (Lo
>= UR_From_Uint
(Ifirst
));
1525 -- Lo_Chk := (X >= Lo)
1527 Lo_Chk
:= Make_Op_Ge
(Loc
,
1528 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1529 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
1532 -- Lo_Chk := (X > Lo)
1534 Lo_Chk
:= Make_Op_Gt
(Loc
,
1535 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1536 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
1539 -- Check against higher bound
1541 if Truncate
and then Ilast
< 0 then
1542 Hi
:= Succ
(Expr_Type
, UR_From_Uint
(Ilast
));
1546 Hi
:= Pred
(Expr_Type
, UR_From_Uint
(Ilast
+ 1));
1549 elsif abs (Ilast
) < Max_Bound
then
1550 Hi
:= UR_From_Uint
(Ilast
) + Ureal_Half
;
1551 Hi_OK
:= (Ilast
< 0);
1553 Hi
:= Machine
(Expr_Type
, UR_From_Uint
(Ilast
), Round_Even
, Ck_Node
);
1554 Hi_OK
:= (Hi
<= UR_From_Uint
(Ilast
));
1559 -- Hi_Chk := (X <= Hi)
1561 Hi_Chk
:= Make_Op_Le
(Loc
,
1562 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1563 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
1566 -- Hi_Chk := (X < Hi)
1568 Hi_Chk
:= Make_Op_Lt
(Loc
,
1569 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1570 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
1573 -- If the bounds of the target type are the same as those of the base
1574 -- type, the check is an overflow check as a range check is not
1575 -- performed in these cases.
1577 if Expr_Value
(Type_Low_Bound
(Target_Base
)) = Ifirst
1578 and then Expr_Value
(Type_High_Bound
(Target_Base
)) = Ilast
1580 Reason
:= CE_Overflow_Check_Failed
;
1582 Reason
:= CE_Range_Check_Failed
;
1585 -- Raise CE if either conditions does not hold
1587 Insert_Action
(Ck_Node
,
1588 Make_Raise_Constraint_Error
(Loc
,
1589 Condition
=> Make_Op_Not
(Loc
, Make_And_Then
(Loc
, Lo_Chk
, Hi_Chk
)),
1591 end Apply_Float_Conversion_Check
;
1593 ------------------------
1594 -- Apply_Length_Check --
1595 ------------------------
1597 procedure Apply_Length_Check
1599 Target_Typ
: Entity_Id
;
1600 Source_Typ
: Entity_Id
:= Empty
)
1603 Apply_Selected_Length_Checks
1604 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
1605 end Apply_Length_Check
;
1607 -----------------------
1608 -- Apply_Range_Check --
1609 -----------------------
1611 procedure Apply_Range_Check
1613 Target_Typ
: Entity_Id
;
1614 Source_Typ
: Entity_Id
:= Empty
)
1617 Apply_Selected_Range_Checks
1618 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
1619 end Apply_Range_Check
;
1621 ------------------------------
1622 -- Apply_Scalar_Range_Check --
1623 ------------------------------
1625 -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag
1626 -- off if it is already set on.
1628 procedure Apply_Scalar_Range_Check
1630 Target_Typ
: Entity_Id
;
1631 Source_Typ
: Entity_Id
:= Empty
;
1632 Fixed_Int
: Boolean := False)
1634 Parnt
: constant Node_Id
:= Parent
(Expr
);
1636 Arr
: Node_Id
:= Empty
; -- initialize to prevent warning
1637 Arr_Typ
: Entity_Id
:= Empty
; -- initialize to prevent warning
1640 Is_Subscr_Ref
: Boolean;
1641 -- Set true if Expr is a subscript
1643 Is_Unconstrained_Subscr_Ref
: Boolean;
1644 -- Set true if Expr is a subscript of an unconstrained array. In this
1645 -- case we do not attempt to do an analysis of the value against the
1646 -- range of the subscript, since we don't know the actual subtype.
1649 -- Set to True if Expr should be regarded as a real value even though
1650 -- the type of Expr might be discrete.
1652 procedure Bad_Value
;
1653 -- Procedure called if value is determined to be out of range
1659 procedure Bad_Value
is
1661 Apply_Compile_Time_Constraint_Error
1662 (Expr
, "value not in range of}?", CE_Range_Check_Failed
,
1667 -- Start of processing for Apply_Scalar_Range_Check
1670 -- Return if check obviously not needed
1673 -- Not needed inside generic
1677 -- Not needed if previous error
1679 or else Target_Typ
= Any_Type
1680 or else Nkind
(Expr
) = N_Error
1682 -- Not needed for non-scalar type
1684 or else not Is_Scalar_Type
(Target_Typ
)
1686 -- Not needed if we know node raises CE already
1688 or else Raises_Constraint_Error
(Expr
)
1693 -- Now, see if checks are suppressed
1696 Is_List_Member
(Expr
) and then Nkind
(Parnt
) = N_Indexed_Component
;
1698 if Is_Subscr_Ref
then
1699 Arr
:= Prefix
(Parnt
);
1700 Arr_Typ
:= Get_Actual_Subtype_If_Available
(Arr
);
1703 if not Do_Range_Check
(Expr
) then
1705 -- Subscript reference. Check for Index_Checks suppressed
1707 if Is_Subscr_Ref
then
1709 -- Check array type and its base type
1711 if Index_Checks_Suppressed
(Arr_Typ
)
1712 or else Index_Checks_Suppressed
(Base_Type
(Arr_Typ
))
1716 -- Check array itself if it is an entity name
1718 elsif Is_Entity_Name
(Arr
)
1719 and then Index_Checks_Suppressed
(Entity
(Arr
))
1723 -- Check expression itself if it is an entity name
1725 elsif Is_Entity_Name
(Expr
)
1726 and then Index_Checks_Suppressed
(Entity
(Expr
))
1731 -- All other cases, check for Range_Checks suppressed
1734 -- Check target type and its base type
1736 if Range_Checks_Suppressed
(Target_Typ
)
1737 or else Range_Checks_Suppressed
(Base_Type
(Target_Typ
))
1741 -- Check expression itself if it is an entity name
1743 elsif Is_Entity_Name
(Expr
)
1744 and then Range_Checks_Suppressed
(Entity
(Expr
))
1748 -- If Expr is part of an assignment statement, then check left
1749 -- side of assignment if it is an entity name.
1751 elsif Nkind
(Parnt
) = N_Assignment_Statement
1752 and then Is_Entity_Name
(Name
(Parnt
))
1753 and then Range_Checks_Suppressed
(Entity
(Name
(Parnt
)))
1760 -- Do not set range checks if they are killed
1762 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
1763 and then Kill_Range_Check
(Expr
)
1768 -- Do not set range checks for any values from System.Scalar_Values
1769 -- since the whole idea of such values is to avoid checking them!
1771 if Is_Entity_Name
(Expr
)
1772 and then Is_RTU
(Scope
(Entity
(Expr
)), System_Scalar_Values
)
1777 -- Now see if we need a check
1779 if No
(Source_Typ
) then
1780 S_Typ
:= Etype
(Expr
);
1782 S_Typ
:= Source_Typ
;
1785 if not Is_Scalar_Type
(S_Typ
) or else S_Typ
= Any_Type
then
1789 Is_Unconstrained_Subscr_Ref
:=
1790 Is_Subscr_Ref
and then not Is_Constrained
(Arr_Typ
);
1792 -- Always do a range check if the source type includes infinities and
1793 -- the target type does not include infinities. We do not do this if
1794 -- range checks are killed.
1796 if Is_Floating_Point_Type
(S_Typ
)
1797 and then Has_Infinities
(S_Typ
)
1798 and then not Has_Infinities
(Target_Typ
)
1800 Enable_Range_Check
(Expr
);
1803 -- Return if we know expression is definitely in the range of the target
1804 -- type as determined by Determine_Range. Right now we only do this for
1805 -- discrete types, and not fixed-point or floating-point types.
1807 -- The additional less-precise tests below catch these cases
1809 -- Note: skip this if we are given a source_typ, since the point of
1810 -- supplying a Source_Typ is to stop us looking at the expression.
1811 -- We could sharpen this test to be out parameters only ???
1813 if Is_Discrete_Type
(Target_Typ
)
1814 and then Is_Discrete_Type
(Etype
(Expr
))
1815 and then not Is_Unconstrained_Subscr_Ref
1816 and then No
(Source_Typ
)
1819 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1820 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1825 if Compile_Time_Known_Value
(Tlo
)
1826 and then Compile_Time_Known_Value
(Thi
)
1829 Lov
: constant Uint
:= Expr_Value
(Tlo
);
1830 Hiv
: constant Uint
:= Expr_Value
(Thi
);
1833 -- If range is null, we for sure have a constraint error
1834 -- (we don't even need to look at the value involved,
1835 -- since all possible values will raise CE).
1842 -- Otherwise determine range of value
1844 Determine_Range
(Expr
, OK
, Lo
, Hi
);
1848 -- If definitely in range, all OK
1850 if Lo
>= Lov
and then Hi
<= Hiv
then
1853 -- If definitely not in range, warn
1855 elsif Lov
> Hi
or else Hiv
< Lo
then
1859 -- Otherwise we don't know
1871 Is_Floating_Point_Type
(S_Typ
)
1872 or else (Is_Fixed_Point_Type
(S_Typ
) and then not Fixed_Int
);
1874 -- Check if we can determine at compile time whether Expr is in the
1875 -- range of the target type. Note that if S_Typ is within the bounds
1876 -- of Target_Typ then this must be the case. This check is meaningful
1877 -- only if this is not a conversion between integer and real types.
1879 if not Is_Unconstrained_Subscr_Ref
1881 Is_Discrete_Type
(S_Typ
) = Is_Discrete_Type
(Target_Typ
)
1883 (In_Subrange_Of
(S_Typ
, Target_Typ
, Fixed_Int
)
1885 Is_In_Range
(Expr
, Target_Typ
, Fixed_Int
, Int_Real
))
1889 elsif Is_Out_Of_Range
(Expr
, Target_Typ
, Fixed_Int
, Int_Real
) then
1893 -- In the floating-point case, we only do range checks if the type is
1894 -- constrained. We definitely do NOT want range checks for unconstrained
1895 -- types, since we want to have infinities
1897 elsif Is_Floating_Point_Type
(S_Typ
) then
1898 if Is_Constrained
(S_Typ
) then
1899 Enable_Range_Check
(Expr
);
1902 -- For all other cases we enable a range check unconditionally
1905 Enable_Range_Check
(Expr
);
1908 end Apply_Scalar_Range_Check
;
1910 ----------------------------------
1911 -- Apply_Selected_Length_Checks --
1912 ----------------------------------
1914 procedure Apply_Selected_Length_Checks
1916 Target_Typ
: Entity_Id
;
1917 Source_Typ
: Entity_Id
;
1918 Do_Static
: Boolean)
1921 R_Result
: Check_Result
;
1924 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1925 Checks_On
: constant Boolean :=
1926 (not Index_Checks_Suppressed
(Target_Typ
))
1928 (not Length_Checks_Suppressed
(Target_Typ
));
1931 if not Expander_Active
then
1936 Selected_Length_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
1938 for J
in 1 .. 2 loop
1939 R_Cno
:= R_Result
(J
);
1940 exit when No
(R_Cno
);
1942 -- A length check may mention an Itype which is attached to a
1943 -- subsequent node. At the top level in a package this can cause
1944 -- an order-of-elaboration problem, so we make sure that the itype
1945 -- is referenced now.
1947 if Ekind
(Current_Scope
) = E_Package
1948 and then Is_Compilation_Unit
(Current_Scope
)
1950 Ensure_Defined
(Target_Typ
, Ck_Node
);
1952 if Present
(Source_Typ
) then
1953 Ensure_Defined
(Source_Typ
, Ck_Node
);
1955 elsif Is_Itype
(Etype
(Ck_Node
)) then
1956 Ensure_Defined
(Etype
(Ck_Node
), Ck_Node
);
1960 -- If the item is a conditional raise of constraint error, then have
1961 -- a look at what check is being performed and ???
1963 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
1964 and then Present
(Condition
(R_Cno
))
1966 Cond
:= Condition
(R_Cno
);
1968 -- Case where node does not now have a dynamic check
1970 if not Has_Dynamic_Length_Check
(Ck_Node
) then
1972 -- If checks are on, just insert the check
1975 Insert_Action
(Ck_Node
, R_Cno
);
1977 if not Do_Static
then
1978 Set_Has_Dynamic_Length_Check
(Ck_Node
);
1981 -- If checks are off, then analyze the length check after
1982 -- temporarily attaching it to the tree in case the relevant
1983 -- condition can be evaluted at compile time. We still want a
1984 -- compile time warning in this case.
1987 Set_Parent
(R_Cno
, Ck_Node
);
1992 -- Output a warning if the condition is known to be True
1994 if Is_Entity_Name
(Cond
)
1995 and then Entity
(Cond
) = Standard_True
1997 Apply_Compile_Time_Constraint_Error
1998 (Ck_Node
, "wrong length for array of}?",
1999 CE_Length_Check_Failed
,
2003 -- If we were only doing a static check, or if checks are not
2004 -- on, then we want to delete the check, since it is not needed.
2005 -- We do this by replacing the if statement by a null statement
2007 elsif Do_Static
or else not Checks_On
then
2008 Remove_Warning_Messages
(R_Cno
);
2009 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
2013 Install_Static_Check
(R_Cno
, Loc
);
2016 end Apply_Selected_Length_Checks
;
2018 ---------------------------------
2019 -- Apply_Selected_Range_Checks --
2020 ---------------------------------
2022 procedure Apply_Selected_Range_Checks
2024 Target_Typ
: Entity_Id
;
2025 Source_Typ
: Entity_Id
;
2026 Do_Static
: Boolean)
2029 R_Result
: Check_Result
;
2032 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
2033 Checks_On
: constant Boolean :=
2034 (not Index_Checks_Suppressed
(Target_Typ
))
2036 (not Range_Checks_Suppressed
(Target_Typ
));
2039 if not Expander_Active
or else not Checks_On
then
2044 Selected_Range_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
2046 for J
in 1 .. 2 loop
2048 R_Cno
:= R_Result
(J
);
2049 exit when No
(R_Cno
);
2051 -- If the item is a conditional raise of constraint error, then have
2052 -- a look at what check is being performed and ???
2054 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
2055 and then Present
(Condition
(R_Cno
))
2057 Cond
:= Condition
(R_Cno
);
2059 if not Has_Dynamic_Range_Check
(Ck_Node
) then
2060 Insert_Action
(Ck_Node
, R_Cno
);
2062 if not Do_Static
then
2063 Set_Has_Dynamic_Range_Check
(Ck_Node
);
2067 -- Output a warning if the condition is known to be True
2069 if Is_Entity_Name
(Cond
)
2070 and then Entity
(Cond
) = Standard_True
2072 -- Since an N_Range is technically not an expression, we have
2073 -- to set one of the bounds to C_E and then just flag the
2074 -- N_Range. The warning message will point to the lower bound
2075 -- and complain about a range, which seems OK.
2077 if Nkind
(Ck_Node
) = N_Range
then
2078 Apply_Compile_Time_Constraint_Error
2079 (Low_Bound
(Ck_Node
), "static range out of bounds of}?",
2080 CE_Range_Check_Failed
,
2084 Set_Raises_Constraint_Error
(Ck_Node
);
2087 Apply_Compile_Time_Constraint_Error
2088 (Ck_Node
, "static value out of range of}?",
2089 CE_Range_Check_Failed
,
2094 -- If we were only doing a static check, or if checks are not
2095 -- on, then we want to delete the check, since it is not needed.
2096 -- We do this by replacing the if statement by a null statement
2098 elsif Do_Static
or else not Checks_On
then
2099 Remove_Warning_Messages
(R_Cno
);
2100 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
2104 Install_Static_Check
(R_Cno
, Loc
);
2107 end Apply_Selected_Range_Checks
;
2109 -------------------------------
2110 -- Apply_Static_Length_Check --
2111 -------------------------------
2113 procedure Apply_Static_Length_Check
2115 Target_Typ
: Entity_Id
;
2116 Source_Typ
: Entity_Id
:= Empty
)
2119 Apply_Selected_Length_Checks
2120 (Expr
, Target_Typ
, Source_Typ
, Do_Static
=> True);
2121 end Apply_Static_Length_Check
;
2123 -------------------------------------
2124 -- Apply_Subscript_Validity_Checks --
2125 -------------------------------------
2127 procedure Apply_Subscript_Validity_Checks
(Expr
: Node_Id
) is
2131 pragma Assert
(Nkind
(Expr
) = N_Indexed_Component
);
2133 -- Loop through subscripts
2135 Sub
:= First
(Expressions
(Expr
));
2136 while Present
(Sub
) loop
2138 -- Check one subscript. Note that we do not worry about enumeration
2139 -- type with holes, since we will convert the value to a Pos value
2140 -- for the subscript, and that convert will do the necessary validity
2143 Ensure_Valid
(Sub
, Holes_OK
=> True);
2145 -- Move to next subscript
2149 end Apply_Subscript_Validity_Checks
;
2151 ----------------------------------
2152 -- Apply_Type_Conversion_Checks --
2153 ----------------------------------
2155 procedure Apply_Type_Conversion_Checks
(N
: Node_Id
) is
2156 Target_Type
: constant Entity_Id
:= Etype
(N
);
2157 Target_Base
: constant Entity_Id
:= Base_Type
(Target_Type
);
2158 Expr
: constant Node_Id
:= Expression
(N
);
2159 Expr_Type
: constant Entity_Id
:= Etype
(Expr
);
2162 if Inside_A_Generic
then
2165 -- Skip these checks if serious errors detected, there are some nasty
2166 -- situations of incomplete trees that blow things up.
2168 elsif Serious_Errors_Detected
> 0 then
2171 -- Scalar type conversions of the form Target_Type (Expr) require a
2172 -- range check if we cannot be sure that Expr is in the base type of
2173 -- Target_Typ and also that Expr is in the range of Target_Typ. These
2174 -- are not quite the same condition from an implementation point of
2175 -- view, but clearly the second includes the first.
2177 elsif Is_Scalar_Type
(Target_Type
) then
2179 Conv_OK
: constant Boolean := Conversion_OK
(N
);
2180 -- If the Conversion_OK flag on the type conversion is set and no
2181 -- floating point type is involved in the type conversion then
2182 -- fixed point values must be read as integral values.
2184 Float_To_Int
: constant Boolean :=
2185 Is_Floating_Point_Type
(Expr_Type
)
2186 and then Is_Integer_Type
(Target_Type
);
2189 if not Overflow_Checks_Suppressed
(Target_Base
)
2190 and then not In_Subrange_Of
(Expr_Type
, Target_Base
, Conv_OK
)
2191 and then not Float_To_Int
2193 Activate_Overflow_Check
(N
);
2196 if not Range_Checks_Suppressed
(Target_Type
)
2197 and then not Range_Checks_Suppressed
(Expr_Type
)
2199 if Float_To_Int
then
2200 Apply_Float_Conversion_Check
(Expr
, Target_Type
);
2202 Apply_Scalar_Range_Check
2203 (Expr
, Target_Type
, Fixed_Int
=> Conv_OK
);
2208 elsif Comes_From_Source
(N
)
2209 and then Is_Record_Type
(Target_Type
)
2210 and then Is_Derived_Type
(Target_Type
)
2211 and then not Is_Tagged_Type
(Target_Type
)
2212 and then not Is_Constrained
(Target_Type
)
2213 and then Present
(Stored_Constraint
(Target_Type
))
2215 -- An unconstrained derived type may have inherited discriminant
2216 -- Build an actual discriminant constraint list using the stored
2217 -- constraint, to verify that the expression of the parent type
2218 -- satisfies the constraints imposed by the (unconstrained!)
2219 -- derived type. This applies to value conversions, not to view
2220 -- conversions of tagged types.
2223 Loc
: constant Source_Ptr
:= Sloc
(N
);
2225 Constraint
: Elmt_Id
;
2226 Discr_Value
: Node_Id
;
2229 New_Constraints
: constant Elist_Id
:= New_Elmt_List
;
2230 Old_Constraints
: constant Elist_Id
:=
2231 Discriminant_Constraint
(Expr_Type
);
2234 Constraint
:= First_Elmt
(Stored_Constraint
(Target_Type
));
2235 while Present
(Constraint
) loop
2236 Discr_Value
:= Node
(Constraint
);
2238 if Is_Entity_Name
(Discr_Value
)
2239 and then Ekind
(Entity
(Discr_Value
)) = E_Discriminant
2241 Discr
:= Corresponding_Discriminant
(Entity
(Discr_Value
));
2244 and then Scope
(Discr
) = Base_Type
(Expr_Type
)
2246 -- Parent is constrained by new discriminant. Obtain
2247 -- Value of original discriminant in expression. If the
2248 -- new discriminant has been used to constrain more than
2249 -- one of the stored discriminants, this will provide the
2250 -- required consistency check.
2253 Make_Selected_Component
(Loc
,
2255 Duplicate_Subexpr_No_Checks
2256 (Expr
, Name_Req
=> True),
2258 Make_Identifier
(Loc
, Chars
(Discr
))),
2262 -- Discriminant of more remote ancestor ???
2267 -- Derived type definition has an explicit value for this
2268 -- stored discriminant.
2272 (Duplicate_Subexpr_No_Checks
(Discr_Value
),
2276 Next_Elmt
(Constraint
);
2279 -- Use the unconstrained expression type to retrieve the
2280 -- discriminants of the parent, and apply momentarily the
2281 -- discriminant constraint synthesized above.
2283 Set_Discriminant_Constraint
(Expr_Type
, New_Constraints
);
2284 Cond
:= Build_Discriminant_Checks
(Expr
, Expr_Type
);
2285 Set_Discriminant_Constraint
(Expr_Type
, Old_Constraints
);
2288 Make_Raise_Constraint_Error
(Loc
,
2290 Reason
=> CE_Discriminant_Check_Failed
));
2293 -- For arrays, conversions are applied during expansion, to take into
2294 -- accounts changes of representation. The checks become range checks on
2295 -- the base type or length checks on the subtype, depending on whether
2296 -- the target type is unconstrained or constrained.
2301 end Apply_Type_Conversion_Checks
;
2303 ----------------------------------------------
2304 -- Apply_Universal_Integer_Attribute_Checks --
2305 ----------------------------------------------
2307 procedure Apply_Universal_Integer_Attribute_Checks
(N
: Node_Id
) is
2308 Loc
: constant Source_Ptr
:= Sloc
(N
);
2309 Typ
: constant Entity_Id
:= Etype
(N
);
2312 if Inside_A_Generic
then
2315 -- Nothing to do if checks are suppressed
2317 elsif Range_Checks_Suppressed
(Typ
)
2318 and then Overflow_Checks_Suppressed
(Typ
)
2322 -- Nothing to do if the attribute does not come from source. The
2323 -- internal attributes we generate of this type do not need checks,
2324 -- and furthermore the attempt to check them causes some circular
2325 -- elaboration orders when dealing with packed types.
2327 elsif not Comes_From_Source
(N
) then
2330 -- If the prefix is a selected component that depends on a discriminant
2331 -- the check may improperly expose a discriminant instead of using
2332 -- the bounds of the object itself. Set the type of the attribute to
2333 -- the base type of the context, so that a check will be imposed when
2334 -- needed (e.g. if the node appears as an index).
2336 elsif Nkind
(Prefix
(N
)) = N_Selected_Component
2337 and then Ekind
(Typ
) = E_Signed_Integer_Subtype
2338 and then Depends_On_Discriminant
(Scalar_Range
(Typ
))
2340 Set_Etype
(N
, Base_Type
(Typ
));
2342 -- Otherwise, replace the attribute node with a type conversion node
2343 -- whose expression is the attribute, retyped to universal integer, and
2344 -- whose subtype mark is the target type. The call to analyze this
2345 -- conversion will set range and overflow checks as required for proper
2346 -- detection of an out of range value.
2349 Set_Etype
(N
, Universal_Integer
);
2350 Set_Analyzed
(N
, True);
2353 Make_Type_Conversion
(Loc
,
2354 Subtype_Mark
=> New_Occurrence_Of
(Typ
, Loc
),
2355 Expression
=> Relocate_Node
(N
)));
2357 Analyze_And_Resolve
(N
, Typ
);
2361 end Apply_Universal_Integer_Attribute_Checks
;
2363 -------------------------------
2364 -- Build_Discriminant_Checks --
2365 -------------------------------
2367 function Build_Discriminant_Checks
2369 T_Typ
: Entity_Id
) return Node_Id
2371 Loc
: constant Source_Ptr
:= Sloc
(N
);
2374 Disc_Ent
: Entity_Id
;
2378 function Aggregate_Discriminant_Val
(Disc
: Entity_Id
) return Node_Id
;
2380 ----------------------------------
2381 -- Aggregate_Discriminant_Value --
2382 ----------------------------------
2384 function Aggregate_Discriminant_Val
(Disc
: Entity_Id
) return Node_Id
is
2388 -- The aggregate has been normalized with named associations. We use
2389 -- the Chars field to locate the discriminant to take into account
2390 -- discriminants in derived types, which carry the same name as those
2393 Assoc
:= First
(Component_Associations
(N
));
2394 while Present
(Assoc
) loop
2395 if Chars
(First
(Choices
(Assoc
))) = Chars
(Disc
) then
2396 return Expression
(Assoc
);
2402 -- Discriminant must have been found in the loop above
2404 raise Program_Error
;
2405 end Aggregate_Discriminant_Val
;
2407 -- Start of processing for Build_Discriminant_Checks
2410 -- Loop through discriminants evolving the condition
2413 Disc
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
2415 -- For a fully private type, use the discriminants of the parent type
2417 if Is_Private_Type
(T_Typ
)
2418 and then No
(Full_View
(T_Typ
))
2420 Disc_Ent
:= First_Discriminant
(Etype
(Base_Type
(T_Typ
)));
2422 Disc_Ent
:= First_Discriminant
(T_Typ
);
2425 while Present
(Disc
) loop
2426 Dval
:= Node
(Disc
);
2428 if Nkind
(Dval
) = N_Identifier
2429 and then Ekind
(Entity
(Dval
)) = E_Discriminant
2431 Dval
:= New_Occurrence_Of
(Discriminal
(Entity
(Dval
)), Loc
);
2433 Dval
:= Duplicate_Subexpr_No_Checks
(Dval
);
2436 -- If we have an Unchecked_Union node, we can infer the discriminants
2439 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
2441 Get_Discriminant_Value
(
2442 First_Discriminant
(T_Typ
),
2444 Stored_Constraint
(T_Typ
)));
2446 elsif Nkind
(N
) = N_Aggregate
then
2448 Duplicate_Subexpr_No_Checks
2449 (Aggregate_Discriminant_Val
(Disc_Ent
));
2453 Make_Selected_Component
(Loc
,
2455 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
2457 Make_Identifier
(Loc
, Chars
(Disc_Ent
)));
2459 Set_Is_In_Discriminant_Check
(Dref
);
2462 Evolve_Or_Else
(Cond
,
2465 Right_Opnd
=> Dval
));
2468 Next_Discriminant
(Disc_Ent
);
2472 end Build_Discriminant_Checks
;
2478 function Check_Needed
(Nod
: Node_Id
; Check
: Check_Type
) return Boolean is
2486 -- Always check if not simple entity
2488 if Nkind
(Nod
) not in N_Has_Entity
2489 or else not Comes_From_Source
(Nod
)
2494 -- Look up tree for short circuit
2501 if K
not in N_Subexpr
then
2504 -- Or/Or Else case, left operand must be equality test
2506 elsif K
= N_Op_Or
or else K
= N_Or_Else
then
2507 exit when N
= Right_Opnd
(P
)
2508 and then Nkind
(Left_Opnd
(P
)) = N_Op_Eq
;
2510 -- And/And then case, left operand must be inequality test
2512 elsif K
= N_Op_And
or else K
= N_And_Then
then
2513 exit when N
= Right_Opnd
(P
)
2514 and then Nkind
(Left_Opnd
(P
)) = N_Op_Ne
;
2520 -- If we fall through the loop, then we have a conditional with an
2521 -- appropriate test as its left operand. So test further.
2525 if Nkind
(L
) = N_Op_Not
then
2526 L
:= Right_Opnd
(L
);
2529 R
:= Right_Opnd
(L
);
2532 -- Left operand of test must match original variable
2534 if Nkind
(L
) not in N_Has_Entity
2535 or else Entity
(L
) /= Entity
(Nod
)
2540 -- Right operand of test must be key value (zero or null)
2543 when Access_Check
=>
2544 if not Known_Null
(R
) then
2548 when Division_Check
=>
2549 if not Compile_Time_Known_Value
(R
)
2550 or else Expr_Value
(R
) /= Uint_0
2556 raise Program_Error
;
2559 -- Here we have the optimizable case, warn if not short-circuited
2561 if K
= N_Op_And
or else K
= N_Op_Or
then
2563 when Access_Check
=>
2565 ("Constraint_Error may be raised (access check)?",
2567 when Division_Check
=>
2569 ("Constraint_Error may be raised (zero divide)?",
2573 raise Program_Error
;
2576 if K
= N_Op_And
then
2577 Error_Msg_N
("use `AND THEN` instead of AND?", P
);
2579 Error_Msg_N
("use `OR ELSE` instead of OR?", P
);
2582 -- If not short-circuited, we need the ckeck
2586 -- If short-circuited, we can omit the check
2593 -----------------------------------
2594 -- Check_Valid_Lvalue_Subscripts --
2595 -----------------------------------
2597 procedure Check_Valid_Lvalue_Subscripts
(Expr
: Node_Id
) is
2599 -- Skip this if range checks are suppressed
2601 if Range_Checks_Suppressed
(Etype
(Expr
)) then
2604 -- Only do this check for expressions that come from source. We assume
2605 -- that expander generated assignments explicitly include any necessary
2606 -- checks. Note that this is not just an optimization, it avoids
2607 -- infinite recursions!
2609 elsif not Comes_From_Source
(Expr
) then
2612 -- For a selected component, check the prefix
2614 elsif Nkind
(Expr
) = N_Selected_Component
then
2615 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
2618 -- Case of indexed component
2620 elsif Nkind
(Expr
) = N_Indexed_Component
then
2621 Apply_Subscript_Validity_Checks
(Expr
);
2623 -- Prefix may itself be or contain an indexed component, and these
2624 -- subscripts need checking as well.
2626 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
2628 end Check_Valid_Lvalue_Subscripts
;
2630 ----------------------------------
2631 -- Null_Exclusion_Static_Checks --
2632 ----------------------------------
2634 procedure Null_Exclusion_Static_Checks
(N
: Node_Id
) is
2635 Error_Node
: Node_Id
;
2637 Has_Null
: constant Boolean := Has_Null_Exclusion
(N
);
2638 K
: constant Node_Kind
:= Nkind
(N
);
2643 (K
= N_Component_Declaration
2644 or else K
= N_Discriminant_Specification
2645 or else K
= N_Function_Specification
2646 or else K
= N_Object_Declaration
2647 or else K
= N_Parameter_Specification
);
2649 if K
= N_Function_Specification
then
2650 Typ
:= Etype
(Defining_Entity
(N
));
2652 Typ
:= Etype
(Defining_Identifier
(N
));
2656 when N_Component_Declaration
=>
2657 if Present
(Access_Definition
(Component_Definition
(N
))) then
2658 Error_Node
:= Component_Definition
(N
);
2660 Error_Node
:= Subtype_Indication
(Component_Definition
(N
));
2663 when N_Discriminant_Specification
=>
2664 Error_Node
:= Discriminant_Type
(N
);
2666 when N_Function_Specification
=>
2667 Error_Node
:= Result_Definition
(N
);
2669 when N_Object_Declaration
=>
2670 Error_Node
:= Object_Definition
(N
);
2672 when N_Parameter_Specification
=>
2673 Error_Node
:= Parameter_Type
(N
);
2676 raise Program_Error
;
2681 -- Enforce legality rule 3.10 (13): A null exclusion can only be
2682 -- applied to an access [sub]type.
2684 if not Is_Access_Type
(Typ
) then
2686 ("`NOT NULL` allowed only for an access type", Error_Node
);
2688 -- Enforce legality rule RM 3.10(14/1): A null exclusion can only
2689 -- be applied to a [sub]type that does not exclude null already.
2691 elsif Can_Never_Be_Null
(Typ
)
2693 -- No need to check itypes that have a null exclusion because
2694 -- they are already examined at their point of creation.
2696 and then not Is_Itype
(Typ
)
2699 ("`NOT NULL` not allowed (& already excludes null)",
2704 -- Check that null-excluding objects are always initialized
2706 if K
= N_Object_Declaration
2707 and then No
(Expression
(N
))
2708 and then not No_Initialization
(N
)
2710 -- Add an expression that assigns null. This node is needed by
2711 -- Apply_Compile_Time_Constraint_Error, which will replace this with
2712 -- a Constraint_Error node.
2714 Set_Expression
(N
, Make_Null
(Sloc
(N
)));
2715 Set_Etype
(Expression
(N
), Etype
(Defining_Identifier
(N
)));
2717 Apply_Compile_Time_Constraint_Error
2718 (N
=> Expression
(N
),
2719 Msg
=> "(Ada 2005) null-excluding objects must be initialized?",
2720 Reason
=> CE_Null_Not_Allowed
);
2723 -- Check that a null-excluding component, formal or object is not
2724 -- being assigned a null value. Otherwise generate a warning message
2725 -- and replace Expression (N) by a N_Contraint_Error node.
2727 if K
/= N_Function_Specification
then
2728 Expr
:= Expression
(N
);
2730 if Present
(Expr
) and then Known_Null
(Expr
) then
2732 when N_Component_Declaration |
2733 N_Discriminant_Specification
=>
2734 Apply_Compile_Time_Constraint_Error
2736 Msg
=> "(Ada 2005) null not allowed " &
2737 "in null-excluding components?",
2738 Reason
=> CE_Null_Not_Allowed
);
2740 when N_Object_Declaration
=>
2741 Apply_Compile_Time_Constraint_Error
2743 Msg
=> "(Ada 2005) null not allowed " &
2744 "in null-excluding objects?",
2745 Reason
=> CE_Null_Not_Allowed
);
2747 when N_Parameter_Specification
=>
2748 Apply_Compile_Time_Constraint_Error
2750 Msg
=> "(Ada 2005) null not allowed " &
2751 "in null-excluding formals?",
2752 Reason
=> CE_Null_Not_Allowed
);
2759 end Null_Exclusion_Static_Checks
;
2761 ----------------------------------
2762 -- Conditional_Statements_Begin --
2763 ----------------------------------
2765 procedure Conditional_Statements_Begin
is
2767 Saved_Checks_TOS
:= Saved_Checks_TOS
+ 1;
2769 -- If stack overflows, kill all checks, that way we know to simply reset
2770 -- the number of saved checks to zero on return. This should never occur
2773 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
2776 -- In the normal case, we just make a new stack entry saving the current
2777 -- number of saved checks for a later restore.
2780 Saved_Checks_Stack
(Saved_Checks_TOS
) := Num_Saved_Checks
;
2782 if Debug_Flag_CC
then
2783 w
("Conditional_Statements_Begin: Num_Saved_Checks = ",
2787 end Conditional_Statements_Begin
;
2789 --------------------------------
2790 -- Conditional_Statements_End --
2791 --------------------------------
2793 procedure Conditional_Statements_End
is
2795 pragma Assert
(Saved_Checks_TOS
> 0);
2797 -- If the saved checks stack overflowed, then we killed all checks, so
2798 -- setting the number of saved checks back to zero is correct. This
2799 -- should never occur in practice.
2801 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
2802 Num_Saved_Checks
:= 0;
2804 -- In the normal case, restore the number of saved checks from the top
2808 Num_Saved_Checks
:= Saved_Checks_Stack
(Saved_Checks_TOS
);
2809 if Debug_Flag_CC
then
2810 w
("Conditional_Statements_End: Num_Saved_Checks = ",
2815 Saved_Checks_TOS
:= Saved_Checks_TOS
- 1;
2816 end Conditional_Statements_End
;
2818 ---------------------
2819 -- Determine_Range --
2820 ---------------------
2822 Cache_Size
: constant := 2 ** 10;
2823 type Cache_Index
is range 0 .. Cache_Size
- 1;
2824 -- Determine size of below cache (power of 2 is more efficient!)
2826 Determine_Range_Cache_N
: array (Cache_Index
) of Node_Id
;
2827 Determine_Range_Cache_Lo
: array (Cache_Index
) of Uint
;
2828 Determine_Range_Cache_Hi
: array (Cache_Index
) of Uint
;
2829 -- The above arrays are used to implement a small direct cache for
2830 -- Determine_Range calls. Because of the way Determine_Range recursively
2831 -- traces subexpressions, and because overflow checking calls the routine
2832 -- on the way up the tree, a quadratic behavior can otherwise be
2833 -- encountered in large expressions. The cache entry for node N is stored
2834 -- in the (N mod Cache_Size) entry, and can be validated by checking the
2835 -- actual node value stored there.
2837 procedure Determine_Range
2843 Typ
: constant Entity_Id
:= Etype
(N
);
2847 -- Lo and Hi bounds of left operand
2851 -- Lo and Hi bounds of right (or only) operand
2854 -- Temp variable used to hold a bound node
2857 -- High bound of base type of expression
2861 -- Refined values for low and high bounds, after tightening
2864 -- Used in lower level calls to indicate if call succeeded
2866 Cindex
: Cache_Index
;
2867 -- Used to search cache
2869 function OK_Operands
return Boolean;
2870 -- Used for binary operators. Determines the ranges of the left and
2871 -- right operands, and if they are both OK, returns True, and puts
2872 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left
2878 function OK_Operands
return Boolean is
2880 Determine_Range
(Left_Opnd
(N
), OK1
, Lo_Left
, Hi_Left
);
2886 Determine_Range
(Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
);
2890 -- Start of processing for Determine_Range
2893 -- Prevent junk warnings by initializing range variables
2900 -- If the type is not discrete, or is undefined, then we can't do
2901 -- anything about determining the range.
2903 if No
(Typ
) or else not Is_Discrete_Type
(Typ
)
2904 or else Error_Posted
(N
)
2910 -- For all other cases, we can determine the range
2914 -- If value is compile time known, then the possible range is the one
2915 -- value that we know this expression definitely has!
2917 if Compile_Time_Known_Value
(N
) then
2918 Lo
:= Expr_Value
(N
);
2923 -- Return if already in the cache
2925 Cindex
:= Cache_Index
(N
mod Cache_Size
);
2927 if Determine_Range_Cache_N
(Cindex
) = N
then
2928 Lo
:= Determine_Range_Cache_Lo
(Cindex
);
2929 Hi
:= Determine_Range_Cache_Hi
(Cindex
);
2933 -- Otherwise, start by finding the bounds of the type of the expression,
2934 -- the value cannot be outside this range (if it is, then we have an
2935 -- overflow situation, which is a separate check, we are talking here
2936 -- only about the expression value).
2938 -- We use the actual bound unless it is dynamic, in which case use the
2939 -- corresponding base type bound if possible. If we can't get a bound
2940 -- then we figure we can't determine the range (a peculiar case, that
2941 -- perhaps cannot happen, but there is no point in bombing in this
2942 -- optimization circuit.
2944 -- First the low bound
2946 Bound
:= Type_Low_Bound
(Typ
);
2948 if Compile_Time_Known_Value
(Bound
) then
2949 Lo
:= Expr_Value
(Bound
);
2951 elsif Compile_Time_Known_Value
(Type_Low_Bound
(Base_Type
(Typ
))) then
2952 Lo
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
2959 -- Now the high bound
2961 Bound
:= Type_High_Bound
(Typ
);
2963 -- We need the high bound of the base type later on, and this should
2964 -- always be compile time known. Again, it is not clear that this
2965 -- can ever be false, but no point in bombing.
2967 if Compile_Time_Known_Value
(Type_High_Bound
(Base_Type
(Typ
))) then
2968 Hbound
:= Expr_Value
(Type_High_Bound
(Base_Type
(Typ
)));
2976 -- If we have a static subtype, then that may have a tighter bound so
2977 -- use the upper bound of the subtype instead in this case.
2979 if Compile_Time_Known_Value
(Bound
) then
2980 Hi
:= Expr_Value
(Bound
);
2983 -- We may be able to refine this value in certain situations. If any
2984 -- refinement is possible, then Lor and Hir are set to possibly tighter
2985 -- bounds, and OK1 is set to True.
2989 -- For unary plus, result is limited by range of operand
2992 Determine_Range
(Right_Opnd
(N
), OK1
, Lor
, Hir
);
2994 -- For unary minus, determine range of operand, and negate it
2997 Determine_Range
(Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
);
3004 -- For binary addition, get range of each operand and do the
3005 -- addition to get the result range.
3009 Lor
:= Lo_Left
+ Lo_Right
;
3010 Hir
:= Hi_Left
+ Hi_Right
;
3013 -- Division is tricky. The only case we consider is where the right
3014 -- operand is a positive constant, and in this case we simply divide
3015 -- the bounds of the left operand
3019 if Lo_Right
= Hi_Right
3020 and then Lo_Right
> 0
3022 Lor
:= Lo_Left
/ Lo_Right
;
3023 Hir
:= Hi_Left
/ Lo_Right
;
3030 -- For binary subtraction, get range of each operand and do the worst
3031 -- case subtraction to get the result range.
3033 when N_Op_Subtract
=>
3035 Lor
:= Lo_Left
- Hi_Right
;
3036 Hir
:= Hi_Left
- Lo_Right
;
3039 -- For MOD, if right operand is a positive constant, then result must
3040 -- be in the allowable range of mod results.
3044 if Lo_Right
= Hi_Right
3045 and then Lo_Right
/= 0
3047 if Lo_Right
> 0 then
3049 Hir
:= Lo_Right
- 1;
3051 else -- Lo_Right < 0
3052 Lor
:= Lo_Right
+ 1;
3061 -- For REM, if right operand is a positive constant, then result must
3062 -- be in the allowable range of mod results.
3066 if Lo_Right
= Hi_Right
3067 and then Lo_Right
/= 0
3070 Dval
: constant Uint
:= (abs Lo_Right
) - 1;
3073 -- The sign of the result depends on the sign of the
3074 -- dividend (but not on the sign of the divisor, hence
3075 -- the abs operation above).
3095 -- Attribute reference cases
3097 when N_Attribute_Reference
=>
3098 case Attribute_Name
(N
) is
3100 -- For Pos/Val attributes, we can refine the range using the
3101 -- possible range of values of the attribute expression
3103 when Name_Pos | Name_Val
=>
3104 Determine_Range
(First
(Expressions
(N
)), OK1
, Lor
, Hir
);
3106 -- For Length attribute, use the bounds of the corresponding
3107 -- index type to refine the range.
3111 Atyp
: Entity_Id
:= Etype
(Prefix
(N
));
3119 if Is_Access_Type
(Atyp
) then
3120 Atyp
:= Designated_Type
(Atyp
);
3123 -- For string literal, we know exact value
3125 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
3127 Lo
:= String_Literal_Length
(Atyp
);
3128 Hi
:= String_Literal_Length
(Atyp
);
3132 -- Otherwise check for expression given
3134 if No
(Expressions
(N
)) then
3138 UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
3141 Indx
:= First_Index
(Atyp
);
3142 for J
in 2 .. Inum
loop
3143 Indx
:= Next_Index
(Indx
);
3147 (Type_Low_Bound
(Etype
(Indx
)), OK1
, LL
, LU
);
3151 (Type_High_Bound
(Etype
(Indx
)), OK1
, UL
, UU
);
3155 -- The maximum value for Length is the biggest
3156 -- possible gap between the values of the bounds.
3157 -- But of course, this value cannot be negative.
3159 Hir
:= UI_Max
(Uint_0
, UU
- LL
);
3161 -- For constrained arrays, the minimum value for
3162 -- Length is taken from the actual value of the
3163 -- bounds, since the index will be exactly of
3166 if Is_Constrained
(Atyp
) then
3167 Lor
:= UI_Max
(Uint_0
, UL
- LU
);
3169 -- For an unconstrained array, the minimum value
3170 -- for length is always zero.
3179 -- No special handling for other attributes
3180 -- Probably more opportunities exist here ???
3187 -- For type conversion from one discrete type to another, we can
3188 -- refine the range using the converted value.
3190 when N_Type_Conversion
=>
3191 Determine_Range
(Expression
(N
), OK1
, Lor
, Hir
);
3193 -- Nothing special to do for all other expression kinds
3201 -- At this stage, if OK1 is true, then we know that the actual
3202 -- result of the computed expression is in the range Lor .. Hir.
3203 -- We can use this to restrict the possible range of results.
3207 -- If the refined value of the low bound is greater than the
3208 -- type high bound, then reset it to the more restrictive
3209 -- value. However, we do NOT do this for the case of a modular
3210 -- type where the possible upper bound on the value is above the
3211 -- base type high bound, because that means the result could wrap.
3214 and then not (Is_Modular_Integer_Type
(Typ
)
3215 and then Hir
> Hbound
)
3220 -- Similarly, if the refined value of the high bound is less
3221 -- than the value so far, then reset it to the more restrictive
3222 -- value. Again, we do not do this if the refined low bound is
3223 -- negative for a modular type, since this would wrap.
3226 and then not (Is_Modular_Integer_Type
(Typ
)
3227 and then Lor
< Uint_0
)
3233 -- Set cache entry for future call and we are all done
3235 Determine_Range_Cache_N
(Cindex
) := N
;
3236 Determine_Range_Cache_Lo
(Cindex
) := Lo
;
3237 Determine_Range_Cache_Hi
(Cindex
) := Hi
;
3240 -- If any exception occurs, it means that we have some bug in the compiler
3241 -- possibly triggered by a previous error, or by some unforseen peculiar
3242 -- occurrence. However, this is only an optimization attempt, so there is
3243 -- really no point in crashing the compiler. Instead we just decide, too
3244 -- bad, we can't figure out a range in this case after all.
3249 -- Debug flag K disables this behavior (useful for debugging)
3251 if Debug_Flag_K
then
3259 end Determine_Range
;
3261 ------------------------------------
3262 -- Discriminant_Checks_Suppressed --
3263 ------------------------------------
3265 function Discriminant_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3268 if Is_Unchecked_Union
(E
) then
3270 elsif Checks_May_Be_Suppressed
(E
) then
3271 return Is_Check_Suppressed
(E
, Discriminant_Check
);
3275 return Scope_Suppress
(Discriminant_Check
);
3276 end Discriminant_Checks_Suppressed
;
3278 --------------------------------
3279 -- Division_Checks_Suppressed --
3280 --------------------------------
3282 function Division_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3284 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
3285 return Is_Check_Suppressed
(E
, Division_Check
);
3287 return Scope_Suppress
(Division_Check
);
3289 end Division_Checks_Suppressed
;
3291 -----------------------------------
3292 -- Elaboration_Checks_Suppressed --
3293 -----------------------------------
3295 function Elaboration_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3297 -- The complication in this routine is that if we are in the dynamic
3298 -- model of elaboration, we also check All_Checks, since All_Checks
3299 -- does not set Elaboration_Check explicitly.
3302 if Kill_Elaboration_Checks
(E
) then
3305 elsif Checks_May_Be_Suppressed
(E
) then
3306 if Is_Check_Suppressed
(E
, Elaboration_Check
) then
3308 elsif Dynamic_Elaboration_Checks
then
3309 return Is_Check_Suppressed
(E
, All_Checks
);
3316 if Scope_Suppress
(Elaboration_Check
) then
3318 elsif Dynamic_Elaboration_Checks
then
3319 return Scope_Suppress
(All_Checks
);
3323 end Elaboration_Checks_Suppressed
;
3325 ---------------------------
3326 -- Enable_Overflow_Check --
3327 ---------------------------
3329 procedure Enable_Overflow_Check
(N
: Node_Id
) is
3330 Typ
: constant Entity_Id
:= Base_Type
(Etype
(N
));
3339 if Debug_Flag_CC
then
3340 w
("Enable_Overflow_Check for node ", Int
(N
));
3341 Write_Str
(" Source location = ");
3346 -- Nothing to do if the range of the result is known OK. We skip this
3347 -- for conversions, since the caller already did the check, and in any
3348 -- case the condition for deleting the check for a type conversion is
3349 -- different in any case.
3351 if Nkind
(N
) /= N_Type_Conversion
then
3352 Determine_Range
(N
, OK
, Lo
, Hi
);
3354 -- Note in the test below that we assume that if a bound of the
3355 -- range is equal to that of the type. That's not quite accurate
3356 -- but we do this for the following reasons:
3358 -- a) The way that Determine_Range works, it will typically report
3359 -- the bounds of the value as being equal to the bounds of the
3360 -- type, because it either can't tell anything more precise, or
3361 -- does not think it is worth the effort to be more precise.
3363 -- b) It is very unusual to have a situation in which this would
3364 -- generate an unnecessary overflow check (an example would be
3365 -- a subtype with a range 0 .. Integer'Last - 1 to which the
3366 -- literal value one is added.
3368 -- c) The alternative is a lot of special casing in this routine
3369 -- which would partially duplicate Determine_Range processing.
3372 and then Lo
> Expr_Value
(Type_Low_Bound
(Typ
))
3373 and then Hi
< Expr_Value
(Type_High_Bound
(Typ
))
3375 if Debug_Flag_CC
then
3376 w
("No overflow check required");
3383 -- If not in optimizing mode, set flag and we are done. We are also done
3384 -- (and just set the flag) if the type is not a discrete type, since it
3385 -- is not worth the effort to eliminate checks for other than discrete
3386 -- types. In addition, we take this same path if we have stored the
3387 -- maximum number of checks possible already (a very unlikely situation,
3388 -- but we do not want to blow up!)
3390 if Optimization_Level
= 0
3391 or else not Is_Discrete_Type
(Etype
(N
))
3392 or else Num_Saved_Checks
= Saved_Checks
'Last
3394 Activate_Overflow_Check
(N
);
3396 if Debug_Flag_CC
then
3397 w
("Optimization off");
3403 -- Otherwise evaluate and check the expression
3408 Target_Type
=> Empty
,
3414 if Debug_Flag_CC
then
3415 w
("Called Find_Check");
3419 w
(" Check_Num = ", Chk
);
3420 w
(" Ent = ", Int
(Ent
));
3421 Write_Str
(" Ofs = ");
3426 -- If check is not of form to optimize, then set flag and we are done
3429 Activate_Overflow_Check
(N
);
3433 -- If check is already performed, then return without setting flag
3436 if Debug_Flag_CC
then
3437 w
("Check suppressed!");
3443 -- Here we will make a new entry for the new check
3445 Activate_Overflow_Check
(N
);
3446 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
3447 Saved_Checks
(Num_Saved_Checks
) :=
3452 Target_Type
=> Empty
);
3454 if Debug_Flag_CC
then
3455 w
("Make new entry, check number = ", Num_Saved_Checks
);
3456 w
(" Entity = ", Int
(Ent
));
3457 Write_Str
(" Offset = ");
3459 w
(" Check_Type = O");
3460 w
(" Target_Type = Empty");
3463 -- If we get an exception, then something went wrong, probably because of
3464 -- an error in the structure of the tree due to an incorrect program. Or it
3465 -- may be a bug in the optimization circuit. In either case the safest
3466 -- thing is simply to set the check flag unconditionally.
3470 Activate_Overflow_Check
(N
);
3472 if Debug_Flag_CC
then
3473 w
(" exception occurred, overflow flag set");
3477 end Enable_Overflow_Check
;
3479 ------------------------
3480 -- Enable_Range_Check --
3481 ------------------------
3483 procedure Enable_Range_Check
(N
: Node_Id
) is
3492 -- Return if unchecked type conversion with range check killed. In this
3493 -- case we never set the flag (that's what Kill_Range_Check is about!)
3495 if Nkind
(N
) = N_Unchecked_Type_Conversion
3496 and then Kill_Range_Check
(N
)
3501 -- Check for various cases where we should suppress the range check
3503 -- No check if range checks suppressed for type of node
3505 if Present
(Etype
(N
))
3506 and then Range_Checks_Suppressed
(Etype
(N
))
3510 -- No check if node is an entity name, and range checks are suppressed
3511 -- for this entity, or for the type of this entity.
3513 elsif Is_Entity_Name
(N
)
3514 and then (Range_Checks_Suppressed
(Entity
(N
))
3515 or else Range_Checks_Suppressed
(Etype
(Entity
(N
))))
3519 -- No checks if index of array, and index checks are suppressed for
3520 -- the array object or the type of the array.
3522 elsif Nkind
(Parent
(N
)) = N_Indexed_Component
then
3524 Pref
: constant Node_Id
:= Prefix
(Parent
(N
));
3526 if Is_Entity_Name
(Pref
)
3527 and then Index_Checks_Suppressed
(Entity
(Pref
))
3530 elsif Index_Checks_Suppressed
(Etype
(Pref
)) then
3536 -- Debug trace output
3538 if Debug_Flag_CC
then
3539 w
("Enable_Range_Check for node ", Int
(N
));
3540 Write_Str
(" Source location = ");
3545 -- If not in optimizing mode, set flag and we are done. We are also done
3546 -- (and just set the flag) if the type is not a discrete type, since it
3547 -- is not worth the effort to eliminate checks for other than discrete
3548 -- types. In addition, we take this same path if we have stored the
3549 -- maximum number of checks possible already (a very unlikely situation,
3550 -- but we do not want to blow up!)
3552 if Optimization_Level
= 0
3553 or else No
(Etype
(N
))
3554 or else not Is_Discrete_Type
(Etype
(N
))
3555 or else Num_Saved_Checks
= Saved_Checks
'Last
3557 Activate_Range_Check
(N
);
3559 if Debug_Flag_CC
then
3560 w
("Optimization off");
3566 -- Otherwise find out the target type
3570 -- For assignment, use left side subtype
3572 if Nkind
(P
) = N_Assignment_Statement
3573 and then Expression
(P
) = N
3575 Ttyp
:= Etype
(Name
(P
));
3577 -- For indexed component, use subscript subtype
3579 elsif Nkind
(P
) = N_Indexed_Component
then
3586 Atyp
:= Etype
(Prefix
(P
));
3588 if Is_Access_Type
(Atyp
) then
3589 Atyp
:= Designated_Type
(Atyp
);
3591 -- If the prefix is an access to an unconstrained array,
3592 -- perform check unconditionally: it depends on the bounds of
3593 -- an object and we cannot currently recognize whether the test
3594 -- may be redundant.
3596 if not Is_Constrained
(Atyp
) then
3597 Activate_Range_Check
(N
);
3601 -- Ditto if the prefix is an explicit dereference whose designated
3602 -- type is unconstrained.
3604 elsif Nkind
(Prefix
(P
)) = N_Explicit_Dereference
3605 and then not Is_Constrained
(Atyp
)
3607 Activate_Range_Check
(N
);
3611 Indx
:= First_Index
(Atyp
);
3612 Subs
:= First
(Expressions
(P
));
3615 Ttyp
:= Etype
(Indx
);
3624 -- For now, ignore all other cases, they are not so interesting
3627 if Debug_Flag_CC
then
3628 w
(" target type not found, flag set");
3631 Activate_Range_Check
(N
);
3635 -- Evaluate and check the expression
3640 Target_Type
=> Ttyp
,
3646 if Debug_Flag_CC
then
3647 w
("Called Find_Check");
3648 w
("Target_Typ = ", Int
(Ttyp
));
3652 w
(" Check_Num = ", Chk
);
3653 w
(" Ent = ", Int
(Ent
));
3654 Write_Str
(" Ofs = ");
3659 -- If check is not of form to optimize, then set flag and we are done
3662 if Debug_Flag_CC
then
3663 w
(" expression not of optimizable type, flag set");
3666 Activate_Range_Check
(N
);
3670 -- If check is already performed, then return without setting flag
3673 if Debug_Flag_CC
then
3674 w
("Check suppressed!");
3680 -- Here we will make a new entry for the new check
3682 Activate_Range_Check
(N
);
3683 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
3684 Saved_Checks
(Num_Saved_Checks
) :=
3689 Target_Type
=> Ttyp
);
3691 if Debug_Flag_CC
then
3692 w
("Make new entry, check number = ", Num_Saved_Checks
);
3693 w
(" Entity = ", Int
(Ent
));
3694 Write_Str
(" Offset = ");
3696 w
(" Check_Type = R");
3697 w
(" Target_Type = ", Int
(Ttyp
));
3698 pg
(Union_Id
(Ttyp
));
3701 -- If we get an exception, then something went wrong, probably because of
3702 -- an error in the structure of the tree due to an incorrect program. Or
3703 -- it may be a bug in the optimization circuit. In either case the safest
3704 -- thing is simply to set the check flag unconditionally.
3708 Activate_Range_Check
(N
);
3710 if Debug_Flag_CC
then
3711 w
(" exception occurred, range flag set");
3715 end Enable_Range_Check
;
3721 procedure Ensure_Valid
(Expr
: Node_Id
; Holes_OK
: Boolean := False) is
3722 Typ
: constant Entity_Id
:= Etype
(Expr
);
3725 -- Ignore call if we are not doing any validity checking
3727 if not Validity_Checks_On
then
3730 -- Ignore call if range or validity checks suppressed on entity or type
3732 elsif Range_Or_Validity_Checks_Suppressed
(Expr
) then
3735 -- No check required if expression is from the expander, we assume the
3736 -- expander will generate whatever checks are needed. Note that this is
3737 -- not just an optimization, it avoids infinite recursions!
3739 -- Unchecked conversions must be checked, unless they are initialized
3740 -- scalar values, as in a component assignment in an init proc.
3742 -- In addition, we force a check if Force_Validity_Checks is set
3744 elsif not Comes_From_Source
(Expr
)
3745 and then not Force_Validity_Checks
3746 and then (Nkind
(Expr
) /= N_Unchecked_Type_Conversion
3747 or else Kill_Range_Check
(Expr
))
3751 -- No check required if expression is known to have valid value
3753 elsif Expr_Known_Valid
(Expr
) then
3756 -- Ignore case of enumeration with holes where the flag is set not to
3757 -- worry about holes, since no special validity check is needed
3759 elsif Is_Enumeration_Type
(Typ
)
3760 and then Has_Non_Standard_Rep
(Typ
)
3765 -- No check required on the left-hand side of an assignment
3767 elsif Nkind
(Parent
(Expr
)) = N_Assignment_Statement
3768 and then Expr
= Name
(Parent
(Expr
))
3772 -- No check on a univeral real constant. The context will eventually
3773 -- convert it to a machine number for some target type, or report an
3776 elsif Nkind
(Expr
) = N_Real_Literal
3777 and then Etype
(Expr
) = Universal_Real
3781 -- If the expression denotes a component of a packed boolean arrray,
3782 -- no possible check applies. We ignore the old ACATS chestnuts that
3783 -- involve Boolean range True..True.
3785 -- Note: validity checks are generated for expressions that yield a
3786 -- scalar type, when it is possible to create a value that is outside of
3787 -- the type. If this is a one-bit boolean no such value exists. This is
3788 -- an optimization, and it also prevents compiler blowing up during the
3789 -- elaboration of improperly expanded packed array references.
3791 elsif Nkind
(Expr
) = N_Indexed_Component
3792 and then Is_Bit_Packed_Array
(Etype
(Prefix
(Expr
)))
3793 and then Root_Type
(Etype
(Expr
)) = Standard_Boolean
3797 -- An annoying special case. If this is an out parameter of a scalar
3798 -- type, then the value is not going to be accessed, therefore it is
3799 -- inappropriate to do any validity check at the call site.
3802 -- Only need to worry about scalar types
3804 if Is_Scalar_Type
(Typ
) then
3814 -- Find actual argument (which may be a parameter association)
3815 -- and the parent of the actual argument (the call statement)
3820 if Nkind
(P
) = N_Parameter_Association
then
3825 -- Only need to worry if we are argument of a procedure call
3826 -- since functions don't have out parameters. If this is an
3827 -- indirect or dispatching call, get signature from the
3830 if Nkind
(P
) = N_Procedure_Call_Statement
then
3831 L
:= Parameter_Associations
(P
);
3833 if Is_Entity_Name
(Name
(P
)) then
3834 E
:= Entity
(Name
(P
));
3836 pragma Assert
(Nkind
(Name
(P
)) = N_Explicit_Dereference
);
3837 E
:= Etype
(Name
(P
));
3840 -- Only need to worry if there are indeed actuals, and if
3841 -- this could be a procedure call, otherwise we cannot get a
3842 -- match (either we are not an argument, or the mode of the
3843 -- formal is not OUT). This test also filters out the
3846 if Is_Non_Empty_List
(L
)
3847 and then Is_Subprogram
(E
)
3849 -- This is the loop through parameters, looking for an
3850 -- OUT parameter for which we are the argument.
3852 F
:= First_Formal
(E
);
3854 while Present
(F
) loop
3855 if Ekind
(F
) = E_Out_Parameter
and then A
= N
then
3868 -- If we fall through, a validity check is required
3870 Insert_Valid_Check
(Expr
);
3873 ----------------------
3874 -- Expr_Known_Valid --
3875 ----------------------
3877 function Expr_Known_Valid
(Expr
: Node_Id
) return Boolean is
3878 Typ
: constant Entity_Id
:= Etype
(Expr
);
3881 -- Non-scalar types are always considered valid, since they never give
3882 -- rise to the issues of erroneous or bounded error behavior that are
3883 -- the concern. In formal reference manual terms the notion of validity
3884 -- only applies to scalar types. Note that even when packed arrays are
3885 -- represented using modular types, they are still arrays semantically,
3886 -- so they are also always valid (in particular, the unused bits can be
3887 -- random rubbish without affecting the validity of the array value).
3889 if not Is_Scalar_Type
(Typ
) or else Is_Packed_Array_Type
(Typ
) then
3892 -- If no validity checking, then everything is considered valid
3894 elsif not Validity_Checks_On
then
3897 -- Floating-point types are considered valid unless floating-point
3898 -- validity checks have been specifically turned on.
3900 elsif Is_Floating_Point_Type
(Typ
)
3901 and then not Validity_Check_Floating_Point
3905 -- If the expression is the value of an object that is known to be
3906 -- valid, then clearly the expression value itself is valid.
3908 elsif Is_Entity_Name
(Expr
)
3909 and then Is_Known_Valid
(Entity
(Expr
))
3913 -- References to discriminants are always considered valid. The value
3914 -- of a discriminant gets checked when the object is built. Within the
3915 -- record, we consider it valid, and it is important to do so, since
3916 -- otherwise we can try to generate bogus validity checks which
3917 -- reference discriminants out of scope. Discriminants of concurrent
3918 -- types are excluded for the same reason.
3920 elsif Is_Entity_Name
(Expr
)
3921 and then Denotes_Discriminant
(Expr
, Check_Concurrent
=> True)
3925 -- If the type is one for which all values are known valid, then we are
3926 -- sure that the value is valid except in the slightly odd case where
3927 -- the expression is a reference to a variable whose size has been
3928 -- explicitly set to a value greater than the object size.
3930 elsif Is_Known_Valid
(Typ
) then
3931 if Is_Entity_Name
(Expr
)
3932 and then Ekind
(Entity
(Expr
)) = E_Variable
3933 and then Esize
(Entity
(Expr
)) > Esize
(Typ
)
3940 -- Integer and character literals always have valid values, where
3941 -- appropriate these will be range checked in any case.
3943 elsif Nkind
(Expr
) = N_Integer_Literal
3945 Nkind
(Expr
) = N_Character_Literal
3949 -- If we have a type conversion or a qualification of a known valid
3950 -- value, then the result will always be valid.
3952 elsif Nkind
(Expr
) = N_Type_Conversion
3954 Nkind
(Expr
) = N_Qualified_Expression
3956 return Expr_Known_Valid
(Expression
(Expr
));
3958 -- The result of any operator is always considered valid, since we
3959 -- assume the necessary checks are done by the operator. For operators
3960 -- on floating-point operations, we must also check when the operation
3961 -- is the right-hand side of an assignment, or is an actual in a call.
3963 elsif Nkind
(Expr
) in N_Op
then
3964 if Is_Floating_Point_Type
(Typ
)
3965 and then Validity_Check_Floating_Point
3967 (Nkind
(Parent
(Expr
)) = N_Assignment_Statement
3968 or else Nkind
(Parent
(Expr
)) = N_Function_Call
3969 or else Nkind
(Parent
(Expr
)) = N_Parameter_Association
)
3976 -- The result of a membership test is always valid, since it is true or
3977 -- false, there are no other possibilities.
3979 elsif Nkind
(Expr
) in N_Membership_Test
then
3982 -- For all other cases, we do not know the expression is valid
3987 end Expr_Known_Valid
;
3993 procedure Find_Check
3995 Check_Type
: Character;
3996 Target_Type
: Entity_Id
;
3997 Entry_OK
: out Boolean;
3998 Check_Num
: out Nat
;
3999 Ent
: out Entity_Id
;
4002 function Within_Range_Of
4003 (Target_Type
: Entity_Id
;
4004 Check_Type
: Entity_Id
) return Boolean;
4005 -- Given a requirement for checking a range against Target_Type, and
4006 -- and a range Check_Type against which a check has already been made,
4007 -- determines if the check against check type is sufficient to ensure
4008 -- that no check against Target_Type is required.
4010 ---------------------
4011 -- Within_Range_Of --
4012 ---------------------
4014 function Within_Range_Of
4015 (Target_Type
: Entity_Id
;
4016 Check_Type
: Entity_Id
) return Boolean
4019 if Target_Type
= Check_Type
then
4024 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Type
);
4025 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Type
);
4026 Clo
: constant Node_Id
:= Type_Low_Bound
(Check_Type
);
4027 Chi
: constant Node_Id
:= Type_High_Bound
(Check_Type
);
4031 or else (Compile_Time_Known_Value
(Tlo
)
4033 Compile_Time_Known_Value
(Clo
)
4035 Expr_Value
(Clo
) >= Expr_Value
(Tlo
)))
4038 or else (Compile_Time_Known_Value
(Thi
)
4040 Compile_Time_Known_Value
(Chi
)
4042 Expr_Value
(Chi
) <= Expr_Value
(Clo
)))
4050 end Within_Range_Of
;
4052 -- Start of processing for Find_Check
4055 -- Establish default, to avoid warnings from GCC
4059 -- Case of expression is simple entity reference
4061 if Is_Entity_Name
(Expr
) then
4062 Ent
:= Entity
(Expr
);
4065 -- Case of expression is entity + known constant
4067 elsif Nkind
(Expr
) = N_Op_Add
4068 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
4069 and then Is_Entity_Name
(Left_Opnd
(Expr
))
4071 Ent
:= Entity
(Left_Opnd
(Expr
));
4072 Ofs
:= Expr_Value
(Right_Opnd
(Expr
));
4074 -- Case of expression is entity - known constant
4076 elsif Nkind
(Expr
) = N_Op_Subtract
4077 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
4078 and then Is_Entity_Name
(Left_Opnd
(Expr
))
4080 Ent
:= Entity
(Left_Opnd
(Expr
));
4081 Ofs
:= UI_Negate
(Expr_Value
(Right_Opnd
(Expr
)));
4083 -- Any other expression is not of the right form
4092 -- Come here with expression of appropriate form, check if entity is an
4093 -- appropriate one for our purposes.
4095 if (Ekind
(Ent
) = E_Variable
4097 Ekind
(Ent
) = E_Constant
4099 Ekind
(Ent
) = E_Loop_Parameter
4101 Ekind
(Ent
) = E_In_Parameter
)
4102 and then not Is_Library_Level_Entity
(Ent
)
4110 -- See if there is matching check already
4112 for J
in reverse 1 .. Num_Saved_Checks
loop
4114 SC
: Saved_Check
renames Saved_Checks
(J
);
4117 if SC
.Killed
= False
4118 and then SC
.Entity
= Ent
4119 and then SC
.Offset
= Ofs
4120 and then SC
.Check_Type
= Check_Type
4121 and then Within_Range_Of
(Target_Type
, SC
.Target_Type
)
4129 -- If we fall through entry was not found
4135 ---------------------------------
4136 -- Generate_Discriminant_Check --
4137 ---------------------------------
4139 -- Note: the code for this procedure is derived from the
4140 -- Emit_Discriminant_Check Routine in trans.c.
4142 procedure Generate_Discriminant_Check
(N
: Node_Id
) is
4143 Loc
: constant Source_Ptr
:= Sloc
(N
);
4144 Pref
: constant Node_Id
:= Prefix
(N
);
4145 Sel
: constant Node_Id
:= Selector_Name
(N
);
4147 Orig_Comp
: constant Entity_Id
:=
4148 Original_Record_Component
(Entity
(Sel
));
4149 -- The original component to be checked
4151 Discr_Fct
: constant Entity_Id
:=
4152 Discriminant_Checking_Func
(Orig_Comp
);
4153 -- The discriminant checking function
4156 -- One discriminant to be checked in the type
4158 Real_Discr
: Entity_Id
;
4159 -- Actual discriminant in the call
4161 Pref_Type
: Entity_Id
;
4162 -- Type of relevant prefix (ignoring private/access stuff)
4165 -- List of arguments for function call
4168 -- Keep track of the formal corresponding to the actual we build for
4169 -- each discriminant, in order to be able to perform the necessary type
4173 -- Selected component reference for checking function argument
4176 Pref_Type
:= Etype
(Pref
);
4178 -- Force evaluation of the prefix, so that it does not get evaluated
4179 -- twice (once for the check, once for the actual reference). Such a
4180 -- double evaluation is always a potential source of inefficiency,
4181 -- and is functionally incorrect in the volatile case, or when the
4182 -- prefix may have side-effects. An entity or a component of an
4183 -- entity requires no evaluation.
4185 if Is_Entity_Name
(Pref
) then
4186 if Treat_As_Volatile
(Entity
(Pref
)) then
4187 Force_Evaluation
(Pref
, Name_Req
=> True);
4190 elsif Treat_As_Volatile
(Etype
(Pref
)) then
4191 Force_Evaluation
(Pref
, Name_Req
=> True);
4193 elsif Nkind
(Pref
) = N_Selected_Component
4194 and then Is_Entity_Name
(Prefix
(Pref
))
4199 Force_Evaluation
(Pref
, Name_Req
=> True);
4202 -- For a tagged type, use the scope of the original component to
4203 -- obtain the type, because ???
4205 if Is_Tagged_Type
(Scope
(Orig_Comp
)) then
4206 Pref_Type
:= Scope
(Orig_Comp
);
4208 -- For an untagged derived type, use the discriminants of the parent
4209 -- which have been renamed in the derivation, possibly by a one-to-many
4210 -- discriminant constraint. For non-tagged type, initially get the Etype
4214 if Is_Derived_Type
(Pref_Type
)
4215 and then Number_Discriminants
(Pref_Type
) /=
4216 Number_Discriminants
(Etype
(Base_Type
(Pref_Type
)))
4218 Pref_Type
:= Etype
(Base_Type
(Pref_Type
));
4222 -- We definitely should have a checking function, This routine should
4223 -- not be called if no discriminant checking function is present.
4225 pragma Assert
(Present
(Discr_Fct
));
4227 -- Create the list of the actual parameters for the call. This list
4228 -- is the list of the discriminant fields of the record expression to
4229 -- be discriminant checked.
4232 Formal
:= First_Formal
(Discr_Fct
);
4233 Discr
:= First_Discriminant
(Pref_Type
);
4234 while Present
(Discr
) loop
4236 -- If we have a corresponding discriminant field, and a parent
4237 -- subtype is present, then we want to use the corresponding
4238 -- discriminant since this is the one with the useful value.
4240 if Present
(Corresponding_Discriminant
(Discr
))
4241 and then Ekind
(Pref_Type
) = E_Record_Type
4242 and then Present
(Parent_Subtype
(Pref_Type
))
4244 Real_Discr
:= Corresponding_Discriminant
(Discr
);
4246 Real_Discr
:= Discr
;
4249 -- Construct the reference to the discriminant
4252 Make_Selected_Component
(Loc
,
4254 Unchecked_Convert_To
(Pref_Type
,
4255 Duplicate_Subexpr
(Pref
)),
4256 Selector_Name
=> New_Occurrence_Of
(Real_Discr
, Loc
));
4258 -- Manually analyze and resolve this selected component. We really
4259 -- want it just as it appears above, and do not want the expander
4260 -- playing discriminal games etc with this reference. Then we append
4261 -- the argument to the list we are gathering.
4263 Set_Etype
(Scomp
, Etype
(Real_Discr
));
4264 Set_Analyzed
(Scomp
, True);
4265 Append_To
(Args
, Convert_To
(Etype
(Formal
), Scomp
));
4267 Next_Formal_With_Extras
(Formal
);
4268 Next_Discriminant
(Discr
);
4271 -- Now build and insert the call
4274 Make_Raise_Constraint_Error
(Loc
,
4276 Make_Function_Call
(Loc
,
4277 Name
=> New_Occurrence_Of
(Discr_Fct
, Loc
),
4278 Parameter_Associations
=> Args
),
4279 Reason
=> CE_Discriminant_Check_Failed
));
4280 end Generate_Discriminant_Check
;
4282 ---------------------------
4283 -- Generate_Index_Checks --
4284 ---------------------------
4286 procedure Generate_Index_Checks
(N
: Node_Id
) is
4287 Loc
: constant Source_Ptr
:= Sloc
(N
);
4288 A
: constant Node_Id
:= Prefix
(N
);
4294 -- Ignore call if index checks suppressed for array object or type
4296 if (Is_Entity_Name
(A
) and then Index_Checks_Suppressed
(Entity
(A
)))
4297 or else Index_Checks_Suppressed
(Etype
(A
))
4302 -- Generate the checks
4304 Sub
:= First
(Expressions
(N
));
4306 while Present
(Sub
) loop
4307 if Do_Range_Check
(Sub
) then
4308 Set_Do_Range_Check
(Sub
, False);
4310 -- Force evaluation except for the case of a simple name of a
4311 -- non-volatile entity.
4313 if not Is_Entity_Name
(Sub
)
4314 or else Treat_As_Volatile
(Entity
(Sub
))
4316 Force_Evaluation
(Sub
);
4319 -- Generate a raise of constraint error with the appropriate
4320 -- reason and a condition of the form:
4322 -- Base_Type(Sub) not in array'range (subscript)
4324 -- Note that the reason we generate the conversion to the base
4325 -- type here is that we definitely want the range check to take
4326 -- place, even if it looks like the subtype is OK. Optimization
4327 -- considerations that allow us to omit the check have already
4328 -- been taken into account in the setting of the Do_Range_Check
4334 Num
:= New_List
(Make_Integer_Literal
(Loc
, Ind
));
4338 Make_Raise_Constraint_Error
(Loc
,
4342 Convert_To
(Base_Type
(Etype
(Sub
)),
4343 Duplicate_Subexpr_Move_Checks
(Sub
)),
4345 Make_Attribute_Reference
(Loc
,
4346 Prefix
=> Duplicate_Subexpr_Move_Checks
(A
),
4347 Attribute_Name
=> Name_Range
,
4348 Expressions
=> Num
)),
4349 Reason
=> CE_Index_Check_Failed
));
4355 end Generate_Index_Checks
;
4357 --------------------------
4358 -- Generate_Range_Check --
4359 --------------------------
4361 procedure Generate_Range_Check
4363 Target_Type
: Entity_Id
;
4364 Reason
: RT_Exception_Code
)
4366 Loc
: constant Source_Ptr
:= Sloc
(N
);
4367 Source_Type
: constant Entity_Id
:= Etype
(N
);
4368 Source_Base_Type
: constant Entity_Id
:= Base_Type
(Source_Type
);
4369 Target_Base_Type
: constant Entity_Id
:= Base_Type
(Target_Type
);
4372 -- First special case, if the source type is already within the range
4373 -- of the target type, then no check is needed (probably we should have
4374 -- stopped Do_Range_Check from being set in the first place, but better
4375 -- late than later in preventing junk code!
4377 -- We do NOT apply this if the source node is a literal, since in this
4378 -- case the literal has already been labeled as having the subtype of
4381 if In_Subrange_Of
(Source_Type
, Target_Type
)
4383 (Nkind
(N
) = N_Integer_Literal
4385 Nkind
(N
) = N_Real_Literal
4387 Nkind
(N
) = N_Character_Literal
4390 and then Ekind
(Entity
(N
)) = E_Enumeration_Literal
))
4395 -- We need a check, so force evaluation of the node, so that it does
4396 -- not get evaluated twice (once for the check, once for the actual
4397 -- reference). Such a double evaluation is always a potential source
4398 -- of inefficiency, and is functionally incorrect in the volatile case.
4400 if not Is_Entity_Name
(N
)
4401 or else Treat_As_Volatile
(Entity
(N
))
4403 Force_Evaluation
(N
);
4406 -- The easiest case is when Source_Base_Type and Target_Base_Type are
4407 -- the same since in this case we can simply do a direct check of the
4408 -- value of N against the bounds of Target_Type.
4410 -- [constraint_error when N not in Target_Type]
4412 -- Note: this is by far the most common case, for example all cases of
4413 -- checks on the RHS of assignments are in this category, but not all
4414 -- cases are like this. Notably conversions can involve two types.
4416 if Source_Base_Type
= Target_Base_Type
then
4418 Make_Raise_Constraint_Error
(Loc
,
4421 Left_Opnd
=> Duplicate_Subexpr
(N
),
4422 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
4425 -- Next test for the case where the target type is within the bounds
4426 -- of the base type of the source type, since in this case we can
4427 -- simply convert these bounds to the base type of T to do the test.
4429 -- [constraint_error when N not in
4430 -- Source_Base_Type (Target_Type'First)
4432 -- Source_Base_Type(Target_Type'Last))]
4434 -- The conversions will always work and need no check
4436 elsif In_Subrange_Of
(Target_Type
, Source_Base_Type
) then
4438 Make_Raise_Constraint_Error
(Loc
,
4441 Left_Opnd
=> Duplicate_Subexpr
(N
),
4446 Convert_To
(Source_Base_Type
,
4447 Make_Attribute_Reference
(Loc
,
4449 New_Occurrence_Of
(Target_Type
, Loc
),
4450 Attribute_Name
=> Name_First
)),
4453 Convert_To
(Source_Base_Type
,
4454 Make_Attribute_Reference
(Loc
,
4456 New_Occurrence_Of
(Target_Type
, Loc
),
4457 Attribute_Name
=> Name_Last
)))),
4460 -- Note that at this stage we now that the Target_Base_Type is not in
4461 -- the range of the Source_Base_Type (since even the Target_Type itself
4462 -- is not in this range). It could still be the case that Source_Type is
4463 -- in range of the target base type since we have not checked that case.
4465 -- If that is the case, we can freely convert the source to the target,
4466 -- and then test the target result against the bounds.
4468 elsif In_Subrange_Of
(Source_Type
, Target_Base_Type
) then
4470 -- We make a temporary to hold the value of the converted value
4471 -- (converted to the base type), and then we will do the test against
4474 -- Tnn : constant Target_Base_Type := Target_Base_Type (N);
4475 -- [constraint_error when Tnn not in Target_Type]
4477 -- Then the conversion itself is replaced by an occurrence of Tnn
4480 Tnn
: constant Entity_Id
:=
4481 Make_Defining_Identifier
(Loc
,
4482 Chars
=> New_Internal_Name
('T'));
4485 Insert_Actions
(N
, New_List
(
4486 Make_Object_Declaration
(Loc
,
4487 Defining_Identifier
=> Tnn
,
4488 Object_Definition
=>
4489 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4490 Constant_Present
=> True,
4492 Make_Type_Conversion
(Loc
,
4493 Subtype_Mark
=> New_Occurrence_Of
(Target_Base_Type
, Loc
),
4494 Expression
=> Duplicate_Subexpr
(N
))),
4496 Make_Raise_Constraint_Error
(Loc
,
4499 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
4500 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
4502 Reason
=> Reason
)));
4504 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
4506 -- Set the type of N, because the declaration for Tnn might not
4507 -- be analyzed yet, as is the case if N appears within a record
4508 -- declaration, as a discriminant constraint or expression.
4510 Set_Etype
(N
, Target_Base_Type
);
4513 -- At this stage, we know that we have two scalar types, which are
4514 -- directly convertible, and where neither scalar type has a base
4515 -- range that is in the range of the other scalar type.
4517 -- The only way this can happen is with a signed and unsigned type.
4518 -- So test for these two cases:
4521 -- Case of the source is unsigned and the target is signed
4523 if Is_Unsigned_Type
(Source_Base_Type
)
4524 and then not Is_Unsigned_Type
(Target_Base_Type
)
4526 -- If the source is unsigned and the target is signed, then we
4527 -- know that the source is not shorter than the target (otherwise
4528 -- the source base type would be in the target base type range).
4530 -- In other words, the unsigned type is either the same size as
4531 -- the target, or it is larger. It cannot be smaller.
4534 (Esize
(Source_Base_Type
) >= Esize
(Target_Base_Type
));
4536 -- We only need to check the low bound if the low bound of the
4537 -- target type is non-negative. If the low bound of the target
4538 -- type is negative, then we know that we will fit fine.
4540 -- If the high bound of the target type is negative, then we
4541 -- know we have a constraint error, since we can't possibly
4542 -- have a negative source.
4544 -- With these two checks out of the way, we can do the check
4545 -- using the source type safely
4547 -- This is definitely the most annoying case!
4549 -- [constraint_error
4550 -- when (Target_Type'First >= 0
4552 -- N < Source_Base_Type (Target_Type'First))
4553 -- or else Target_Type'Last < 0
4554 -- or else N > Source_Base_Type (Target_Type'Last)];
4556 -- We turn off all checks since we know that the conversions
4557 -- will work fine, given the guards for negative values.
4560 Make_Raise_Constraint_Error
(Loc
,
4566 Left_Opnd
=> Make_Op_Ge
(Loc
,
4568 Make_Attribute_Reference
(Loc
,
4570 New_Occurrence_Of
(Target_Type
, Loc
),
4571 Attribute_Name
=> Name_First
),
4572 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
4576 Left_Opnd
=> Duplicate_Subexpr
(N
),
4578 Convert_To
(Source_Base_Type
,
4579 Make_Attribute_Reference
(Loc
,
4581 New_Occurrence_Of
(Target_Type
, Loc
),
4582 Attribute_Name
=> Name_First
)))),
4587 Make_Attribute_Reference
(Loc
,
4588 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
4589 Attribute_Name
=> Name_Last
),
4590 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
))),
4594 Left_Opnd
=> Duplicate_Subexpr
(N
),
4596 Convert_To
(Source_Base_Type
,
4597 Make_Attribute_Reference
(Loc
,
4598 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
4599 Attribute_Name
=> Name_Last
)))),
4602 Suppress
=> All_Checks
);
4604 -- Only remaining possibility is that the source is signed and
4605 -- the target is unsigned
4608 pragma Assert
(not Is_Unsigned_Type
(Source_Base_Type
)
4609 and then Is_Unsigned_Type
(Target_Base_Type
));
4611 -- If the source is signed and the target is unsigned, then we
4612 -- know that the target is not shorter than the source (otherwise
4613 -- the target base type would be in the source base type range).
4615 -- In other words, the unsigned type is either the same size as
4616 -- the target, or it is larger. It cannot be smaller.
4618 -- Clearly we have an error if the source value is negative since
4619 -- no unsigned type can have negative values. If the source type
4620 -- is non-negative, then the check can be done using the target
4623 -- Tnn : constant Target_Base_Type (N) := Target_Type;
4625 -- [constraint_error
4626 -- when N < 0 or else Tnn not in Target_Type];
4628 -- We turn off all checks for the conversion of N to the target
4629 -- base type, since we generate the explicit check to ensure that
4630 -- the value is non-negative
4633 Tnn
: constant Entity_Id
:=
4634 Make_Defining_Identifier
(Loc
,
4635 Chars
=> New_Internal_Name
('T'));
4638 Insert_Actions
(N
, New_List
(
4639 Make_Object_Declaration
(Loc
,
4640 Defining_Identifier
=> Tnn
,
4641 Object_Definition
=>
4642 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4643 Constant_Present
=> True,
4645 Make_Type_Conversion
(Loc
,
4647 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4648 Expression
=> Duplicate_Subexpr
(N
))),
4650 Make_Raise_Constraint_Error
(Loc
,
4655 Left_Opnd
=> Duplicate_Subexpr
(N
),
4656 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
4660 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
4662 New_Occurrence_Of
(Target_Type
, Loc
))),
4665 Suppress
=> All_Checks
);
4667 -- Set the Etype explicitly, because Insert_Actions may have
4668 -- placed the declaration in the freeze list for an enclosing
4669 -- construct, and thus it is not analyzed yet.
4671 Set_Etype
(Tnn
, Target_Base_Type
);
4672 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
4676 end Generate_Range_Check
;
4682 function Get_Check_Id
(N
: Name_Id
) return Check_Id
is
4684 -- For standard check name, we can do a direct computation
4686 if N
in First_Check_Name
.. Last_Check_Name
then
4687 return Check_Id
(N
- (First_Check_Name
- 1));
4689 -- For non-standard names added by pragma Check_Name, search table
4692 for J
in All_Checks
+ 1 .. Check_Names
.Last
loop
4693 if Check_Names
.Table
(J
) = N
then
4699 -- No matching name found
4704 ---------------------
4705 -- Get_Discriminal --
4706 ---------------------
4708 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
is
4709 Loc
: constant Source_Ptr
:= Sloc
(E
);
4714 -- The bound can be a bona fide parameter of a protected operation,
4715 -- rather than a prival encoded as an in-parameter.
4717 if No
(Discriminal_Link
(Entity
(Bound
))) then
4721 -- Climb the scope stack looking for an enclosing protected type. If
4722 -- we run out of scopes, return the bound itself.
4725 while Present
(Sc
) loop
4726 if Sc
= Standard_Standard
then
4729 elsif Ekind
(Sc
) = E_Protected_Type
then
4736 D
:= First_Discriminant
(Sc
);
4737 while Present
(D
) loop
4738 if Chars
(D
) = Chars
(Bound
) then
4739 return New_Occurrence_Of
(Discriminal
(D
), Loc
);
4742 Next_Discriminant
(D
);
4746 end Get_Discriminal
;
4748 ----------------------
4749 -- Get_Range_Checks --
4750 ----------------------
4752 function Get_Range_Checks
4754 Target_Typ
: Entity_Id
;
4755 Source_Typ
: Entity_Id
:= Empty
;
4756 Warn_Node
: Node_Id
:= Empty
) return Check_Result
4759 return Selected_Range_Checks
4760 (Ck_Node
, Target_Typ
, Source_Typ
, Warn_Node
);
4761 end Get_Range_Checks
;
4767 function Guard_Access
4770 Ck_Node
: Node_Id
) return Node_Id
4773 if Nkind
(Cond
) = N_Or_Else
then
4774 Set_Paren_Count
(Cond
, 1);
4777 if Nkind
(Ck_Node
) = N_Allocator
then
4784 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
4785 Right_Opnd
=> Make_Null
(Loc
)),
4786 Right_Opnd
=> Cond
);
4790 -----------------------------
4791 -- Index_Checks_Suppressed --
4792 -----------------------------
4794 function Index_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4796 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4797 return Is_Check_Suppressed
(E
, Index_Check
);
4799 return Scope_Suppress
(Index_Check
);
4801 end Index_Checks_Suppressed
;
4807 procedure Initialize
is
4809 for J
in Determine_Range_Cache_N
'Range loop
4810 Determine_Range_Cache_N
(J
) := Empty
;
4815 for J
in Int
range 1 .. All_Checks
loop
4816 Check_Names
.Append
(Name_Id
(Int
(First_Check_Name
) + J
- 1));
4820 -------------------------
4821 -- Insert_Range_Checks --
4822 -------------------------
4824 procedure Insert_Range_Checks
4825 (Checks
: Check_Result
;
4827 Suppress_Typ
: Entity_Id
;
4828 Static_Sloc
: Source_Ptr
:= No_Location
;
4829 Flag_Node
: Node_Id
:= Empty
;
4830 Do_Before
: Boolean := False)
4832 Internal_Flag_Node
: Node_Id
:= Flag_Node
;
4833 Internal_Static_Sloc
: Source_Ptr
:= Static_Sloc
;
4835 Check_Node
: Node_Id
;
4836 Checks_On
: constant Boolean :=
4837 (not Index_Checks_Suppressed
(Suppress_Typ
))
4839 (not Range_Checks_Suppressed
(Suppress_Typ
));
4842 -- For now we just return if Checks_On is false, however this should be
4843 -- enhanced to check for an always True value in the condition and to
4844 -- generate a compilation warning???
4846 if not Expander_Active
or else not Checks_On
then
4850 if Static_Sloc
= No_Location
then
4851 Internal_Static_Sloc
:= Sloc
(Node
);
4854 if No
(Flag_Node
) then
4855 Internal_Flag_Node
:= Node
;
4858 for J
in 1 .. 2 loop
4859 exit when No
(Checks
(J
));
4861 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
4862 and then Present
(Condition
(Checks
(J
)))
4864 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
4865 Check_Node
:= Checks
(J
);
4866 Mark_Rewrite_Insertion
(Check_Node
);
4869 Insert_Before_And_Analyze
(Node
, Check_Node
);
4871 Insert_After_And_Analyze
(Node
, Check_Node
);
4874 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
4879 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
4880 Reason
=> CE_Range_Check_Failed
);
4881 Mark_Rewrite_Insertion
(Check_Node
);
4884 Insert_Before_And_Analyze
(Node
, Check_Node
);
4886 Insert_After_And_Analyze
(Node
, Check_Node
);
4890 end Insert_Range_Checks
;
4892 ------------------------
4893 -- Insert_Valid_Check --
4894 ------------------------
4896 procedure Insert_Valid_Check
(Expr
: Node_Id
) is
4897 Loc
: constant Source_Ptr
:= Sloc
(Expr
);
4901 -- Do not insert if checks off, or if not checking validity
4903 if not Validity_Checks_On
4904 or else Range_Or_Validity_Checks_Suppressed
(Expr
)
4909 -- If we have a checked conversion, then validity check applies to
4910 -- the expression inside the conversion, not the result, since if
4911 -- the expression inside is valid, then so is the conversion result.
4914 while Nkind
(Exp
) = N_Type_Conversion
loop
4915 Exp
:= Expression
(Exp
);
4918 -- We are about to insert the validity check for Exp. We save and
4919 -- reset the Do_Range_Check flag over this validity check, and then
4920 -- put it back for the final original reference (Exp may be rewritten).
4923 DRC
: constant Boolean := Do_Range_Check
(Exp
);
4926 Set_Do_Range_Check
(Exp
, False);
4928 -- Insert the validity check. Note that we do this with validity
4929 -- checks turned off, to avoid recursion, we do not want validity
4930 -- checks on the validity checking code itself!
4934 Make_Raise_Constraint_Error
(Loc
,
4938 Make_Attribute_Reference
(Loc
,
4940 Duplicate_Subexpr_No_Checks
(Exp
, Name_Req
=> True),
4941 Attribute_Name
=> Name_Valid
)),
4942 Reason
=> CE_Invalid_Data
),
4943 Suppress
=> Validity_Check
);
4945 -- If the expression is a a reference to an element of a bit-packed
4946 -- array, then it is rewritten as a renaming declaration. If the
4947 -- expression is an actual in a call, it has not been expanded,
4948 -- waiting for the proper point at which to do it. The same happens
4949 -- with renamings, so that we have to force the expansion now. This
4950 -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb
4953 if Is_Entity_Name
(Exp
)
4954 and then Nkind
(Parent
(Entity
(Exp
))) =
4955 N_Object_Renaming_Declaration
4958 Old_Exp
: constant Node_Id
:= Name
(Parent
(Entity
(Exp
)));
4960 if Nkind
(Old_Exp
) = N_Indexed_Component
4961 and then Is_Bit_Packed_Array
(Etype
(Prefix
(Old_Exp
)))
4963 Expand_Packed_Element_Reference
(Old_Exp
);
4968 -- Put back the Do_Range_Check flag on the resulting (possibly
4969 -- rewritten) expression.
4971 -- Note: it might be thought that a validity check is not required
4972 -- when a range check is present, but that's not the case, because
4973 -- the back end is allowed to assume for the range check that the
4974 -- operand is within its declared range (an assumption that validity
4975 -- checking is all about NOT assuming!)
4977 -- Note: no need to worry about Possible_Local_Raise here, it will
4978 -- already have been called if original node has Do_Range_Check set.
4980 Set_Do_Range_Check
(Exp
, DRC
);
4982 end Insert_Valid_Check
;
4984 ----------------------------------
4985 -- Install_Null_Excluding_Check --
4986 ----------------------------------
4988 procedure Install_Null_Excluding_Check
(N
: Node_Id
) is
4989 Loc
: constant Source_Ptr
:= Sloc
(N
);
4990 Typ
: constant Entity_Id
:= Etype
(N
);
4992 function In_Declarative_Region_Of_Subprogram_Body
return Boolean;
4993 -- Determine whether node N, a reference to an *in* parameter, is
4994 -- inside the declarative region of the current subprogram body.
4996 procedure Mark_Non_Null
;
4997 -- After installation of check, if the node in question is an entity
4998 -- name, then mark this entity as non-null if possible.
5000 ----------------------------------------------
5001 -- In_Declarative_Region_Of_Subprogram_Body --
5002 ----------------------------------------------
5004 function In_Declarative_Region_Of_Subprogram_Body
return Boolean is
5005 E
: constant Entity_Id
:= Entity
(N
);
5006 S
: constant Entity_Id
:= Current_Scope
;
5010 pragma Assert
(Ekind
(E
) = E_In_Parameter
);
5012 -- Two initial context checks. We must be inside a subprogram body
5013 -- with declarations and reference must not appear in nested scopes.
5015 if (Ekind
(S
) /= E_Function
5016 and then Ekind
(S
) /= E_Procedure
)
5017 or else Scope
(E
) /= S
5022 S_Par
:= Parent
(Parent
(S
));
5024 if Nkind
(S_Par
) /= N_Subprogram_Body
5025 or else No
(Declarations
(S_Par
))
5035 -- Retrieve the declaration node of N (if any). Note that N
5036 -- may be a part of a complex initialization expression.
5040 while Present
(P
) loop
5042 -- While traversing the parent chain, we find that N
5043 -- belongs to a statement, thus it may never appear in
5044 -- a declarative region.
5046 if Nkind
(P
) in N_Statement_Other_Than_Procedure_Call
5047 or else Nkind
(P
) = N_Procedure_Call_Statement
5052 if Nkind
(P
) in N_Declaration
5053 and then Nkind
(P
) not in N_Subprogram_Specification
5066 return List_Containing
(N_Decl
) = Declarations
(S_Par
);
5068 end In_Declarative_Region_Of_Subprogram_Body
;
5074 procedure Mark_Non_Null
is
5076 -- Only case of interest is if node N is an entity name
5078 if Is_Entity_Name
(N
) then
5080 -- For sure, we want to clear an indication that this is known to
5081 -- be null, since if we get past this check, it definitely is not!
5083 Set_Is_Known_Null
(Entity
(N
), False);
5085 -- We can mark the entity as known to be non-null if either it is
5086 -- safe to capture the value, or in the case of an IN parameter,
5087 -- which is a constant, if the check we just installed is in the
5088 -- declarative region of the subprogram body. In this latter case,
5089 -- a check is decisive for the rest of the body, since we know we
5090 -- must complete all declarations before executing the body.
5092 if Safe_To_Capture_Value
(N
, Entity
(N
))
5094 (Ekind
(Entity
(N
)) = E_In_Parameter
5095 and then In_Declarative_Region_Of_Subprogram_Body
)
5097 Set_Is_Known_Non_Null
(Entity
(N
));
5102 -- Start of processing for Install_Null_Excluding_Check
5105 pragma Assert
(Is_Access_Type
(Typ
));
5107 -- No check inside a generic (why not???)
5109 if Inside_A_Generic
then
5113 -- No check needed if known to be non-null
5115 if Known_Non_Null
(N
) then
5119 -- If known to be null, here is where we generate a compile time check
5121 if Known_Null
(N
) then
5122 Apply_Compile_Time_Constraint_Error
5124 "null value not allowed here?",
5125 CE_Access_Check_Failed
);
5130 -- If entity is never assigned, for sure a warning is appropriate
5132 if Is_Entity_Name
(N
) then
5133 Check_Unset_Reference
(N
);
5136 -- No check needed if checks are suppressed on the range. Note that we
5137 -- don't set Is_Known_Non_Null in this case (we could legitimately do
5138 -- so, since the program is erroneous, but we don't like to casually
5139 -- propagate such conclusions from erroneosity).
5141 if Access_Checks_Suppressed
(Typ
) then
5145 -- No check needed for access to concurrent record types generated by
5146 -- the expander. This is not just an optimization (though it does indeed
5147 -- remove junk checks). It also avoids generation of junk warnings.
5149 if Nkind
(N
) in N_Has_Chars
5150 and then Chars
(N
) = Name_uObject
5151 and then Is_Concurrent_Record_Type
5152 (Directly_Designated_Type
(Etype
(N
)))
5157 -- Otherwise install access check
5160 Make_Raise_Constraint_Error
(Loc
,
5163 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(N
),
5164 Right_Opnd
=> Make_Null
(Loc
)),
5165 Reason
=> CE_Access_Check_Failed
));
5168 end Install_Null_Excluding_Check
;
5170 --------------------------
5171 -- Install_Static_Check --
5172 --------------------------
5174 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
) is
5175 Stat
: constant Boolean := Is_Static_Expression
(R_Cno
);
5176 Typ
: constant Entity_Id
:= Etype
(R_Cno
);
5180 Make_Raise_Constraint_Error
(Loc
,
5181 Reason
=> CE_Range_Check_Failed
));
5182 Set_Analyzed
(R_Cno
);
5183 Set_Etype
(R_Cno
, Typ
);
5184 Set_Raises_Constraint_Error
(R_Cno
);
5185 Set_Is_Static_Expression
(R_Cno
, Stat
);
5186 end Install_Static_Check
;
5188 ---------------------
5189 -- Kill_All_Checks --
5190 ---------------------
5192 procedure Kill_All_Checks
is
5194 if Debug_Flag_CC
then
5195 w
("Kill_All_Checks");
5198 -- We reset the number of saved checks to zero, and also modify all
5199 -- stack entries for statement ranges to indicate that the number of
5200 -- checks at each level is now zero.
5202 Num_Saved_Checks
:= 0;
5204 for J
in 1 .. Saved_Checks_TOS
loop
5205 Saved_Checks_Stack
(J
) := 0;
5207 end Kill_All_Checks
;
5213 procedure Kill_Checks
(V
: Entity_Id
) is
5215 if Debug_Flag_CC
then
5216 w
("Kill_Checks for entity", Int
(V
));
5219 for J
in 1 .. Num_Saved_Checks
loop
5220 if Saved_Checks
(J
).Entity
= V
then
5221 if Debug_Flag_CC
then
5222 w
(" Checks killed for saved check ", J
);
5225 Saved_Checks
(J
).Killed
:= True;
5230 ------------------------------
5231 -- Length_Checks_Suppressed --
5232 ------------------------------
5234 function Length_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5236 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
5237 return Is_Check_Suppressed
(E
, Length_Check
);
5239 return Scope_Suppress
(Length_Check
);
5241 end Length_Checks_Suppressed
;
5243 --------------------------------
5244 -- Overflow_Checks_Suppressed --
5245 --------------------------------
5247 function Overflow_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5249 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
5250 return Is_Check_Suppressed
(E
, Overflow_Check
);
5252 return Scope_Suppress
(Overflow_Check
);
5254 end Overflow_Checks_Suppressed
;
5255 -----------------------------
5256 -- Range_Checks_Suppressed --
5257 -----------------------------
5259 function Range_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5263 -- Note: for now we always suppress range checks on Vax float types,
5264 -- since Gigi does not know how to generate these checks.
5266 if Vax_Float
(E
) then
5268 elsif Kill_Range_Checks
(E
) then
5270 elsif Checks_May_Be_Suppressed
(E
) then
5271 return Is_Check_Suppressed
(E
, Range_Check
);
5275 return Scope_Suppress
(Range_Check
);
5276 end Range_Checks_Suppressed
;
5278 -----------------------------------------
5279 -- Range_Or_Validity_Checks_Suppressed --
5280 -----------------------------------------
5282 -- Note: the coding would be simpler here if we simply made appropriate
5283 -- calls to Range/Validity_Checks_Suppressed, but that would result in
5284 -- duplicated checks which we prefer to avoid.
5286 function Range_Or_Validity_Checks_Suppressed
5287 (Expr
: Node_Id
) return Boolean
5290 -- Immediate return if scope checks suppressed for either check
5292 if Scope_Suppress
(Range_Check
) or Scope_Suppress
(Validity_Check
) then
5296 -- If no expression, that's odd, decide that checks are suppressed,
5297 -- since we don't want anyone trying to do checks in this case, which
5298 -- is most likely the result of some other error.
5304 -- Expression is present, so perform suppress checks on type
5307 Typ
: constant Entity_Id
:= Etype
(Expr
);
5309 if Vax_Float
(Typ
) then
5311 elsif Checks_May_Be_Suppressed
(Typ
)
5312 and then (Is_Check_Suppressed
(Typ
, Range_Check
)
5314 Is_Check_Suppressed
(Typ
, Validity_Check
))
5320 -- If expression is an entity name, perform checks on this entity
5322 if Is_Entity_Name
(Expr
) then
5324 Ent
: constant Entity_Id
:= Entity
(Expr
);
5326 if Checks_May_Be_Suppressed
(Ent
) then
5327 return Is_Check_Suppressed
(Ent
, Range_Check
)
5328 or else Is_Check_Suppressed
(Ent
, Validity_Check
);
5333 -- If we fall through, no checks suppressed
5336 end Range_Or_Validity_Checks_Suppressed
;
5342 procedure Remove_Checks
(Expr
: Node_Id
) is
5343 Discard
: Traverse_Result
;
5344 pragma Warnings
(Off
, Discard
);
5346 function Process
(N
: Node_Id
) return Traverse_Result
;
5347 -- Process a single node during the traversal
5349 function Traverse
is new Traverse_Func
(Process
);
5350 -- The traversal function itself
5356 function Process
(N
: Node_Id
) return Traverse_Result
is
5358 if Nkind
(N
) not in N_Subexpr
then
5362 Set_Do_Range_Check
(N
, False);
5366 Discard
:= Traverse
(Left_Opnd
(N
));
5369 when N_Attribute_Reference
=>
5370 Set_Do_Overflow_Check
(N
, False);
5372 when N_Function_Call
=>
5373 Set_Do_Tag_Check
(N
, False);
5376 Set_Do_Overflow_Check
(N
, False);
5380 Set_Do_Division_Check
(N
, False);
5383 Set_Do_Length_Check
(N
, False);
5386 Set_Do_Division_Check
(N
, False);
5389 Set_Do_Length_Check
(N
, False);
5392 Set_Do_Division_Check
(N
, False);
5395 Set_Do_Length_Check
(N
, False);
5402 Discard
:= Traverse
(Left_Opnd
(N
));
5405 when N_Selected_Component
=>
5406 Set_Do_Discriminant_Check
(N
, False);
5408 when N_Type_Conversion
=>
5409 Set_Do_Length_Check
(N
, False);
5410 Set_Do_Tag_Check
(N
, False);
5411 Set_Do_Overflow_Check
(N
, False);
5420 -- Start of processing for Remove_Checks
5423 Discard
:= Traverse
(Expr
);
5426 ----------------------------
5427 -- Selected_Length_Checks --
5428 ----------------------------
5430 function Selected_Length_Checks
5432 Target_Typ
: Entity_Id
;
5433 Source_Typ
: Entity_Id
;
5434 Warn_Node
: Node_Id
) return Check_Result
5436 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
5439 Expr_Actual
: Node_Id
;
5441 Cond
: Node_Id
:= Empty
;
5442 Do_Access
: Boolean := False;
5443 Wnode
: Node_Id
:= Warn_Node
;
5444 Ret_Result
: Check_Result
:= (Empty
, Empty
);
5445 Num_Checks
: Natural := 0;
5447 procedure Add_Check
(N
: Node_Id
);
5448 -- Adds the action given to Ret_Result if N is non-Empty
5450 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
;
5451 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5452 -- Comments required ???
5454 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean;
5455 -- True for equal literals and for nodes that denote the same constant
5456 -- entity, even if its value is not a static constant. This includes the
5457 -- case of a discriminal reference within an init proc. Removes some
5458 -- obviously superfluous checks.
5460 function Length_E_Cond
5461 (Exptyp
: Entity_Id
;
5463 Indx
: Nat
) return Node_Id
;
5464 -- Returns expression to compute:
5465 -- Typ'Length /= Exptyp'Length
5467 function Length_N_Cond
5470 Indx
: Nat
) return Node_Id
;
5471 -- Returns expression to compute:
5472 -- Typ'Length /= Expr'Length
5478 procedure Add_Check
(N
: Node_Id
) is
5482 -- For now, ignore attempt to place more than 2 checks ???
5484 if Num_Checks
= 2 then
5488 pragma Assert
(Num_Checks
<= 1);
5489 Num_Checks
:= Num_Checks
+ 1;
5490 Ret_Result
(Num_Checks
) := N
;
5498 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
is
5499 SE
: constant Entity_Id
:= Scope
(E
);
5501 E1
: Entity_Id
:= E
;
5504 if Ekind
(Scope
(E
)) = E_Record_Type
5505 and then Has_Discriminants
(Scope
(E
))
5507 N
:= Build_Discriminal_Subtype_Of_Component
(E
);
5510 Insert_Action
(Ck_Node
, N
);
5511 E1
:= Defining_Identifier
(N
);
5515 if Ekind
(E1
) = E_String_Literal_Subtype
then
5517 Make_Integer_Literal
(Loc
,
5518 Intval
=> String_Literal_Length
(E1
));
5520 elsif SE
/= Standard_Standard
5521 and then Ekind
(Scope
(SE
)) = E_Protected_Type
5522 and then Has_Discriminants
(Scope
(SE
))
5523 and then Has_Completion
(Scope
(SE
))
5524 and then not Inside_Init_Proc
5526 -- If the type whose length is needed is a private component
5527 -- constrained by a discriminant, we must expand the 'Length
5528 -- attribute into an explicit computation, using the discriminal
5529 -- of the current protected operation. This is because the actual
5530 -- type of the prival is constructed after the protected opera-
5531 -- tion has been fully expanded.
5534 Indx_Type
: Node_Id
;
5537 Do_Expand
: Boolean := False;
5540 Indx_Type
:= First_Index
(E
);
5542 for J
in 1 .. Indx
- 1 loop
5543 Next_Index
(Indx_Type
);
5546 Get_Index_Bounds
(Indx_Type
, Lo
, Hi
);
5548 if Nkind
(Lo
) = N_Identifier
5549 and then Ekind
(Entity
(Lo
)) = E_In_Parameter
5551 Lo
:= Get_Discriminal
(E
, Lo
);
5555 if Nkind
(Hi
) = N_Identifier
5556 and then Ekind
(Entity
(Hi
)) = E_In_Parameter
5558 Hi
:= Get_Discriminal
(E
, Hi
);
5563 if not Is_Entity_Name
(Lo
) then
5564 Lo
:= Duplicate_Subexpr_No_Checks
(Lo
);
5567 if not Is_Entity_Name
(Hi
) then
5568 Lo
:= Duplicate_Subexpr_No_Checks
(Hi
);
5574 Make_Op_Subtract
(Loc
,
5578 Right_Opnd
=> Make_Integer_Literal
(Loc
, 1));
5583 Make_Attribute_Reference
(Loc
,
5584 Attribute_Name
=> Name_Length
,
5586 New_Occurrence_Of
(E1
, Loc
));
5589 Set_Expressions
(N
, New_List
(
5590 Make_Integer_Literal
(Loc
, Indx
)));
5599 Make_Attribute_Reference
(Loc
,
5600 Attribute_Name
=> Name_Length
,
5602 New_Occurrence_Of
(E1
, Loc
));
5605 Set_Expressions
(N
, New_List
(
5606 Make_Integer_Literal
(Loc
, Indx
)));
5617 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5620 Make_Attribute_Reference
(Loc
,
5621 Attribute_Name
=> Name_Length
,
5623 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5624 Expressions
=> New_List
(
5625 Make_Integer_Literal
(Loc
, Indx
)));
5632 function Length_E_Cond
5633 (Exptyp
: Entity_Id
;
5635 Indx
: Nat
) return Node_Id
5640 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
5641 Right_Opnd
=> Get_E_Length
(Exptyp
, Indx
));
5648 function Length_N_Cond
5651 Indx
: Nat
) return Node_Id
5656 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
5657 Right_Opnd
=> Get_N_Length
(Expr
, Indx
));
5664 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean is
5667 (Nkind
(L
) = N_Integer_Literal
5668 and then Nkind
(R
) = N_Integer_Literal
5669 and then Intval
(L
) = Intval
(R
))
5673 and then Ekind
(Entity
(L
)) = E_Constant
5674 and then ((Is_Entity_Name
(R
)
5675 and then Entity
(L
) = Entity
(R
))
5677 (Nkind
(R
) = N_Type_Conversion
5678 and then Is_Entity_Name
(Expression
(R
))
5679 and then Entity
(L
) = Entity
(Expression
(R
)))))
5683 and then Ekind
(Entity
(R
)) = E_Constant
5684 and then Nkind
(L
) = N_Type_Conversion
5685 and then Is_Entity_Name
(Expression
(L
))
5686 and then Entity
(R
) = Entity
(Expression
(L
)))
5690 and then Is_Entity_Name
(R
)
5691 and then Entity
(L
) = Entity
(R
)
5692 and then Ekind
(Entity
(L
)) = E_In_Parameter
5693 and then Inside_Init_Proc
);
5696 -- Start of processing for Selected_Length_Checks
5699 if not Expander_Active
then
5703 if Target_Typ
= Any_Type
5704 or else Target_Typ
= Any_Composite
5705 or else Raises_Constraint_Error
(Ck_Node
)
5714 T_Typ
:= Target_Typ
;
5716 if No
(Source_Typ
) then
5717 S_Typ
:= Etype
(Ck_Node
);
5719 S_Typ
:= Source_Typ
;
5722 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
5726 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
5727 S_Typ
:= Designated_Type
(S_Typ
);
5728 T_Typ
:= Designated_Type
(T_Typ
);
5731 -- A simple optimization for the null case
5733 if Known_Null
(Ck_Node
) then
5738 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
5739 if Is_Constrained
(T_Typ
) then
5741 -- The checking code to be generated will freeze the
5742 -- corresponding array type. However, we must freeze the
5743 -- type now, so that the freeze node does not appear within
5744 -- the generated condional expression, but ahead of it.
5746 Freeze_Before
(Ck_Node
, T_Typ
);
5748 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
5749 Exptyp
:= Get_Actual_Subtype
(Ck_Node
);
5751 if Is_Access_Type
(Exptyp
) then
5752 Exptyp
:= Designated_Type
(Exptyp
);
5755 -- String_Literal case. This needs to be handled specially be-
5756 -- cause no index types are available for string literals. The
5757 -- condition is simply:
5759 -- T_Typ'Length = string-literal-length
5761 if Nkind
(Expr_Actual
) = N_String_Literal
5762 and then Ekind
(Etype
(Expr_Actual
)) = E_String_Literal_Subtype
5766 Left_Opnd
=> Get_E_Length
(T_Typ
, 1),
5768 Make_Integer_Literal
(Loc
,
5770 String_Literal_Length
(Etype
(Expr_Actual
))));
5772 -- General array case. Here we have a usable actual subtype for
5773 -- the expression, and the condition is built from the two types
5776 -- T_Typ'Length /= Exptyp'Length or else
5777 -- T_Typ'Length (2) /= Exptyp'Length (2) or else
5778 -- T_Typ'Length (3) /= Exptyp'Length (3) or else
5781 elsif Is_Constrained
(Exptyp
) then
5783 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
5796 -- At the library level, we need to ensure that the type of
5797 -- the object is elaborated before the check itself is
5798 -- emitted. This is only done if the object is in the
5799 -- current compilation unit, otherwise the type is frozen
5800 -- and elaborated in its unit.
5802 if Is_Itype
(Exptyp
)
5804 Ekind
(Cunit_Entity
(Current_Sem_Unit
)) = E_Package
5806 not In_Package_Body
(Cunit_Entity
(Current_Sem_Unit
))
5807 and then In_Open_Scopes
(Scope
(Exptyp
))
5809 Ref_Node
:= Make_Itype_Reference
(Sloc
(Ck_Node
));
5810 Set_Itype
(Ref_Node
, Exptyp
);
5811 Insert_Action
(Ck_Node
, Ref_Node
);
5814 L_Index
:= First_Index
(T_Typ
);
5815 R_Index
:= First_Index
(Exptyp
);
5817 for Indx
in 1 .. Ndims
loop
5818 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
5820 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
5822 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
5823 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
5825 -- Deal with compile time length check. Note that we
5826 -- skip this in the access case, because the access
5827 -- value may be null, so we cannot know statically.
5830 and then Compile_Time_Known_Value
(L_Low
)
5831 and then Compile_Time_Known_Value
(L_High
)
5832 and then Compile_Time_Known_Value
(R_Low
)
5833 and then Compile_Time_Known_Value
(R_High
)
5835 if Expr_Value
(L_High
) >= Expr_Value
(L_Low
) then
5836 L_Length
:= Expr_Value
(L_High
) -
5837 Expr_Value
(L_Low
) + 1;
5839 L_Length
:= UI_From_Int
(0);
5842 if Expr_Value
(R_High
) >= Expr_Value
(R_Low
) then
5843 R_Length
:= Expr_Value
(R_High
) -
5844 Expr_Value
(R_Low
) + 1;
5846 R_Length
:= UI_From_Int
(0);
5849 if L_Length
> R_Length
then
5851 (Compile_Time_Constraint_Error
5852 (Wnode
, "too few elements for}?", T_Typ
));
5854 elsif L_Length
< R_Length
then
5856 (Compile_Time_Constraint_Error
5857 (Wnode
, "too many elements for}?", T_Typ
));
5860 -- The comparison for an individual index subtype
5861 -- is omitted if the corresponding index subtypes
5862 -- statically match, since the result is known to
5863 -- be true. Note that this test is worth while even
5864 -- though we do static evaluation, because non-static
5865 -- subtypes can statically match.
5868 Subtypes_Statically_Match
5869 (Etype
(L_Index
), Etype
(R_Index
))
5872 (Same_Bounds
(L_Low
, R_Low
)
5873 and then Same_Bounds
(L_High
, R_High
))
5876 (Cond
, Length_E_Cond
(Exptyp
, T_Typ
, Indx
));
5885 -- Handle cases where we do not get a usable actual subtype that
5886 -- is constrained. This happens for example in the function call
5887 -- and explicit dereference cases. In these cases, we have to get
5888 -- the length or range from the expression itself, making sure we
5889 -- do not evaluate it more than once.
5891 -- Here Ck_Node is the original expression, or more properly the
5892 -- result of applying Duplicate_Expr to the original tree, forcing
5893 -- the result to be a name.
5897 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
5900 -- Build the condition for the explicit dereference case
5902 for Indx
in 1 .. Ndims
loop
5904 (Cond
, Length_N_Cond
(Ck_Node
, T_Typ
, Indx
));
5911 -- Construct the test and insert into the tree
5913 if Present
(Cond
) then
5915 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
5919 (Make_Raise_Constraint_Error
(Loc
,
5921 Reason
=> CE_Length_Check_Failed
));
5925 end Selected_Length_Checks
;
5927 ---------------------------
5928 -- Selected_Range_Checks --
5929 ---------------------------
5931 function Selected_Range_Checks
5933 Target_Typ
: Entity_Id
;
5934 Source_Typ
: Entity_Id
;
5935 Warn_Node
: Node_Id
) return Check_Result
5937 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
5940 Expr_Actual
: Node_Id
;
5942 Cond
: Node_Id
:= Empty
;
5943 Do_Access
: Boolean := False;
5944 Wnode
: Node_Id
:= Warn_Node
;
5945 Ret_Result
: Check_Result
:= (Empty
, Empty
);
5946 Num_Checks
: Integer := 0;
5948 procedure Add_Check
(N
: Node_Id
);
5949 -- Adds the action given to Ret_Result if N is non-Empty
5951 function Discrete_Range_Cond
5953 Typ
: Entity_Id
) return Node_Id
;
5954 -- Returns expression to compute:
5955 -- Low_Bound (Expr) < Typ'First
5957 -- High_Bound (Expr) > Typ'Last
5959 function Discrete_Expr_Cond
5961 Typ
: Entity_Id
) return Node_Id
;
5962 -- Returns expression to compute:
5967 function Get_E_First_Or_Last
5970 Nam
: Name_Id
) return Node_Id
;
5971 -- Returns expression to compute:
5972 -- E'First or E'Last
5974 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5975 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5976 -- Returns expression to compute:
5977 -- N'First or N'Last using Duplicate_Subexpr_No_Checks
5979 function Range_E_Cond
5980 (Exptyp
: Entity_Id
;
5984 -- Returns expression to compute:
5985 -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
5987 function Range_Equal_E_Cond
5988 (Exptyp
: Entity_Id
;
5990 Indx
: Nat
) return Node_Id
;
5991 -- Returns expression to compute:
5992 -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
5994 function Range_N_Cond
5997 Indx
: Nat
) return Node_Id
;
5998 -- Return expression to compute:
5999 -- Expr'First < Typ'First or else Expr'Last > Typ'Last
6005 procedure Add_Check
(N
: Node_Id
) is
6009 -- For now, ignore attempt to place more than 2 checks ???
6011 if Num_Checks
= 2 then
6015 pragma Assert
(Num_Checks
<= 1);
6016 Num_Checks
:= Num_Checks
+ 1;
6017 Ret_Result
(Num_Checks
) := N
;
6021 -------------------------
6022 -- Discrete_Expr_Cond --
6023 -------------------------
6025 function Discrete_Expr_Cond
6027 Typ
: Entity_Id
) return Node_Id
6035 Convert_To
(Base_Type
(Typ
),
6036 Duplicate_Subexpr_No_Checks
(Expr
)),
6038 Convert_To
(Base_Type
(Typ
),
6039 Get_E_First_Or_Last
(Typ
, 0, Name_First
))),
6044 Convert_To
(Base_Type
(Typ
),
6045 Duplicate_Subexpr_No_Checks
(Expr
)),
6049 Get_E_First_Or_Last
(Typ
, 0, Name_Last
))));
6050 end Discrete_Expr_Cond
;
6052 -------------------------
6053 -- Discrete_Range_Cond --
6054 -------------------------
6056 function Discrete_Range_Cond
6058 Typ
: Entity_Id
) return Node_Id
6060 LB
: Node_Id
:= Low_Bound
(Expr
);
6061 HB
: Node_Id
:= High_Bound
(Expr
);
6063 Left_Opnd
: Node_Id
;
6064 Right_Opnd
: Node_Id
;
6067 if Nkind
(LB
) = N_Identifier
6068 and then Ekind
(Entity
(LB
)) = E_Discriminant
6070 LB
:= New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
6073 if Nkind
(HB
) = N_Identifier
6074 and then Ekind
(Entity
(HB
)) = E_Discriminant
6076 HB
:= New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
6083 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(LB
)),
6087 (Base_Type
(Typ
), Get_E_First_Or_Last
(Typ
, 0, Name_First
)));
6089 if Base_Type
(Typ
) = Typ
then
6092 elsif Compile_Time_Known_Value
(High_Bound
(Scalar_Range
(Typ
)))
6094 Compile_Time_Known_Value
(High_Bound
(Scalar_Range
6097 if Is_Floating_Point_Type
(Typ
) then
6098 if Expr_Value_R
(High_Bound
(Scalar_Range
(Typ
))) =
6099 Expr_Value_R
(High_Bound
(Scalar_Range
(Base_Type
(Typ
))))
6105 if Expr_Value
(High_Bound
(Scalar_Range
(Typ
))) =
6106 Expr_Value
(High_Bound
(Scalar_Range
(Base_Type
(Typ
))))
6117 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(HB
)),
6122 Get_E_First_Or_Last
(Typ
, 0, Name_Last
)));
6124 return Make_Or_Else
(Loc
, Left_Opnd
, Right_Opnd
);
6125 end Discrete_Range_Cond
;
6127 -------------------------
6128 -- Get_E_First_Or_Last --
6129 -------------------------
6131 function Get_E_First_Or_Last
6134 Nam
: Name_Id
) return Node_Id
6142 if Is_Array_Type
(E
) then
6143 N
:= First_Index
(E
);
6145 for J
in 2 .. Indx
loop
6150 N
:= Scalar_Range
(E
);
6153 if Nkind
(N
) = N_Subtype_Indication
then
6154 LB
:= Low_Bound
(Range_Expression
(Constraint
(N
)));
6155 HB
:= High_Bound
(Range_Expression
(Constraint
(N
)));
6157 elsif Is_Entity_Name
(N
) then
6158 LB
:= Type_Low_Bound
(Etype
(N
));
6159 HB
:= Type_High_Bound
(Etype
(N
));
6162 LB
:= Low_Bound
(N
);
6163 HB
:= High_Bound
(N
);
6166 if Nam
= Name_First
then
6172 if Nkind
(Bound
) = N_Identifier
6173 and then Ekind
(Entity
(Bound
)) = E_Discriminant
6175 -- If this is a task discriminant, and we are the body, we must
6176 -- retrieve the corresponding body discriminal. This is another
6177 -- consequence of the early creation of discriminals, and the
6178 -- need to generate constraint checks before their declarations
6179 -- are made visible.
6181 if Is_Concurrent_Record_Type
(Scope
(Entity
(Bound
))) then
6183 Tsk
: constant Entity_Id
:=
6184 Corresponding_Concurrent_Type
6185 (Scope
(Entity
(Bound
)));
6189 if In_Open_Scopes
(Tsk
)
6190 and then Has_Completion
(Tsk
)
6192 -- Find discriminant of original task, and use its
6193 -- current discriminal, which is the renaming within
6196 Disc
:= First_Discriminant
(Tsk
);
6197 while Present
(Disc
) loop
6198 if Chars
(Disc
) = Chars
(Entity
(Bound
)) then
6199 Set_Scope
(Discriminal
(Disc
), Tsk
);
6200 return New_Occurrence_Of
(Discriminal
(Disc
), Loc
);
6203 Next_Discriminant
(Disc
);
6206 -- That loop should always succeed in finding a matching
6207 -- entry and returning. Fatal error if not.
6209 raise Program_Error
;
6213 New_Occurrence_Of
(Discriminal
(Entity
(Bound
)), Loc
);
6217 return New_Occurrence_Of
(Discriminal
(Entity
(Bound
)), Loc
);
6220 elsif Nkind
(Bound
) = N_Identifier
6221 and then Ekind
(Entity
(Bound
)) = E_In_Parameter
6222 and then not Inside_Init_Proc
6224 return Get_Discriminal
(E
, Bound
);
6226 elsif Nkind
(Bound
) = N_Integer_Literal
then
6227 return Make_Integer_Literal
(Loc
, Intval
(Bound
));
6229 -- Case of a bound rewritten to an N_Raise_Constraint_Error node
6230 -- because it is an out-of-range value. Duplicate_Subexpr cannot be
6231 -- called on this node because an N_Raise_Constraint_Error is not
6232 -- side effect free, and we may not assume that we are in the proper
6233 -- context to remove side effects on it at the point of reference.
6235 elsif Nkind
(Bound
) = N_Raise_Constraint_Error
then
6236 return New_Copy_Tree
(Bound
);
6239 return Duplicate_Subexpr_No_Checks
(Bound
);
6241 end Get_E_First_Or_Last
;
6247 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
6250 Make_Attribute_Reference
(Loc
,
6251 Attribute_Name
=> Name_First
,
6253 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
6254 Expressions
=> New_List
(
6255 Make_Integer_Literal
(Loc
, Indx
)));
6262 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
6265 Make_Attribute_Reference
(Loc
,
6266 Attribute_Name
=> Name_Last
,
6268 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
6269 Expressions
=> New_List
(
6270 Make_Integer_Literal
(Loc
, Indx
)));
6277 function Range_E_Cond
6278 (Exptyp
: Entity_Id
;
6280 Indx
: Nat
) return Node_Id
6287 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_First
),
6288 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
6292 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_Last
),
6293 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
6296 ------------------------
6297 -- Range_Equal_E_Cond --
6298 ------------------------
6300 function Range_Equal_E_Cond
6301 (Exptyp
: Entity_Id
;
6303 Indx
: Nat
) return Node_Id
6310 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_First
),
6311 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
6314 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_Last
),
6315 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
6316 end Range_Equal_E_Cond
;
6322 function Range_N_Cond
6325 Indx
: Nat
) return Node_Id
6332 Left_Opnd
=> Get_N_First
(Expr
, Indx
),
6333 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
6337 Left_Opnd
=> Get_N_Last
(Expr
, Indx
),
6338 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
6341 -- Start of processing for Selected_Range_Checks
6344 if not Expander_Active
then
6348 if Target_Typ
= Any_Type
6349 or else Target_Typ
= Any_Composite
6350 or else Raises_Constraint_Error
(Ck_Node
)
6359 T_Typ
:= Target_Typ
;
6361 if No
(Source_Typ
) then
6362 S_Typ
:= Etype
(Ck_Node
);
6364 S_Typ
:= Source_Typ
;
6367 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
6371 -- The order of evaluating T_Typ before S_Typ seems to be critical
6372 -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
6373 -- in, and since Node can be an N_Range node, it might be invalid.
6374 -- Should there be an assert check somewhere for taking the Etype of
6375 -- an N_Range node ???
6377 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
6378 S_Typ
:= Designated_Type
(S_Typ
);
6379 T_Typ
:= Designated_Type
(T_Typ
);
6382 -- A simple optimization for the null case
6384 if Known_Null
(Ck_Node
) then
6389 -- For an N_Range Node, check for a null range and then if not
6390 -- null generate a range check action.
6392 if Nkind
(Ck_Node
) = N_Range
then
6394 -- There's no point in checking a range against itself
6396 if Ck_Node
= Scalar_Range
(T_Typ
) then
6401 T_LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
6402 T_HB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
6403 LB
: constant Node_Id
:= Low_Bound
(Ck_Node
);
6404 HB
: constant Node_Id
:= High_Bound
(Ck_Node
);
6405 Null_Range
: Boolean;
6407 Out_Of_Range_L
: Boolean;
6408 Out_Of_Range_H
: Boolean;
6411 -- Check for case where everything is static and we can
6412 -- do the check at compile time. This is skipped if we
6413 -- have an access type, since the access value may be null.
6415 -- ??? This code can be improved since you only need to know
6416 -- that the two respective bounds (LB & T_LB or HB & T_HB)
6417 -- are known at compile time to emit pertinent messages.
6419 if Compile_Time_Known_Value
(LB
)
6420 and then Compile_Time_Known_Value
(HB
)
6421 and then Compile_Time_Known_Value
(T_LB
)
6422 and then Compile_Time_Known_Value
(T_HB
)
6423 and then not Do_Access
6425 -- Floating-point case
6427 if Is_Floating_Point_Type
(S_Typ
) then
6428 Null_Range
:= Expr_Value_R
(HB
) < Expr_Value_R
(LB
);
6430 (Expr_Value_R
(LB
) < Expr_Value_R
(T_LB
))
6432 (Expr_Value_R
(LB
) > Expr_Value_R
(T_HB
));
6435 (Expr_Value_R
(HB
) > Expr_Value_R
(T_HB
))
6437 (Expr_Value_R
(HB
) < Expr_Value_R
(T_LB
));
6439 -- Fixed or discrete type case
6442 Null_Range
:= Expr_Value
(HB
) < Expr_Value
(LB
);
6444 (Expr_Value
(LB
) < Expr_Value
(T_LB
))
6446 (Expr_Value
(LB
) > Expr_Value
(T_HB
));
6449 (Expr_Value
(HB
) > Expr_Value
(T_HB
))
6451 (Expr_Value
(HB
) < Expr_Value
(T_LB
));
6454 if not Null_Range
then
6455 if Out_Of_Range_L
then
6456 if No
(Warn_Node
) then
6458 (Compile_Time_Constraint_Error
6459 (Low_Bound
(Ck_Node
),
6460 "static value out of range of}?", T_Typ
));
6464 (Compile_Time_Constraint_Error
6466 "static range out of bounds of}?", T_Typ
));
6470 if Out_Of_Range_H
then
6471 if No
(Warn_Node
) then
6473 (Compile_Time_Constraint_Error
6474 (High_Bound
(Ck_Node
),
6475 "static value out of range of}?", T_Typ
));
6479 (Compile_Time_Constraint_Error
6481 "static range out of bounds of}?", T_Typ
));
6489 LB
: Node_Id
:= Low_Bound
(Ck_Node
);
6490 HB
: Node_Id
:= High_Bound
(Ck_Node
);
6493 -- If either bound is a discriminant and we are within the
6494 -- record declaration, it is a use of the discriminant in a
6495 -- constraint of a component, and nothing can be checked
6496 -- here. The check will be emitted within the init proc.
6497 -- Before then, the discriminal has no real meaning.
6498 -- Similarly, if the entity is a discriminal, there is no
6499 -- check to perform yet.
6501 -- The same holds within a discriminated synchronized type,
6502 -- where the discriminant may constrain a component or an
6505 if Nkind
(LB
) = N_Identifier
6506 and then Denotes_Discriminant
(LB
, True)
6508 if Current_Scope
= Scope
(Entity
(LB
))
6509 or else Is_Concurrent_Type
(Current_Scope
)
6510 or else Ekind
(Entity
(LB
)) /= E_Discriminant
6515 New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
6519 if Nkind
(HB
) = N_Identifier
6520 and then Denotes_Discriminant
(HB
, True)
6522 if Current_Scope
= Scope
(Entity
(HB
))
6523 or else Is_Concurrent_Type
(Current_Scope
)
6524 or else Ekind
(Entity
(HB
)) /= E_Discriminant
6529 New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
6533 Cond
:= Discrete_Range_Cond
(Ck_Node
, T_Typ
);
6534 Set_Paren_Count
(Cond
, 1);
6540 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(HB
),
6541 Right_Opnd
=> Duplicate_Subexpr_No_Checks
(LB
)),
6542 Right_Opnd
=> Cond
);
6547 elsif Is_Scalar_Type
(S_Typ
) then
6549 -- This somewhat duplicates what Apply_Scalar_Range_Check does,
6550 -- except the above simply sets a flag in the node and lets
6551 -- gigi generate the check base on the Etype of the expression.
6552 -- Sometimes, however we want to do a dynamic check against an
6553 -- arbitrary target type, so we do that here.
6555 if Ekind
(Base_Type
(S_Typ
)) /= Ekind
(Base_Type
(T_Typ
)) then
6556 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6558 -- For literals, we can tell if the constraint error will be
6559 -- raised at compile time, so we never need a dynamic check, but
6560 -- if the exception will be raised, then post the usual warning,
6561 -- and replace the literal with a raise constraint error
6562 -- expression. As usual, skip this for access types
6564 elsif Compile_Time_Known_Value
(Ck_Node
)
6565 and then not Do_Access
6568 LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
6569 UB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
6571 Out_Of_Range
: Boolean;
6572 Static_Bounds
: constant Boolean :=
6573 Compile_Time_Known_Value
(LB
)
6574 and Compile_Time_Known_Value
(UB
);
6577 -- Following range tests should use Sem_Eval routine ???
6579 if Static_Bounds
then
6580 if Is_Floating_Point_Type
(S_Typ
) then
6582 (Expr_Value_R
(Ck_Node
) < Expr_Value_R
(LB
))
6584 (Expr_Value_R
(Ck_Node
) > Expr_Value_R
(UB
));
6586 else -- fixed or discrete type
6588 Expr_Value
(Ck_Node
) < Expr_Value
(LB
)
6590 Expr_Value
(Ck_Node
) > Expr_Value
(UB
);
6593 -- Bounds of the type are static and the literal is
6594 -- out of range so make a warning message.
6596 if Out_Of_Range
then
6597 if No
(Warn_Node
) then
6599 (Compile_Time_Constraint_Error
6601 "static value out of range of}?", T_Typ
));
6605 (Compile_Time_Constraint_Error
6607 "static value out of range of}?", T_Typ
));
6612 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6616 -- Here for the case of a non-static expression, we need a runtime
6617 -- check unless the source type range is guaranteed to be in the
6618 -- range of the target type.
6621 if not In_Subrange_Of
(S_Typ
, T_Typ
) then
6622 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6627 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
6628 if Is_Constrained
(T_Typ
) then
6630 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
6631 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
6633 if Is_Access_Type
(Exptyp
) then
6634 Exptyp
:= Designated_Type
(Exptyp
);
6637 -- String_Literal case. This needs to be handled specially be-
6638 -- cause no index types are available for string literals. The
6639 -- condition is simply:
6641 -- T_Typ'Length = string-literal-length
6643 if Nkind
(Expr_Actual
) = N_String_Literal
then
6646 -- General array case. Here we have a usable actual subtype for
6647 -- the expression, and the condition is built from the two types
6649 -- T_Typ'First < Exptyp'First or else
6650 -- T_Typ'Last > Exptyp'Last or else
6651 -- T_Typ'First(1) < Exptyp'First(1) or else
6652 -- T_Typ'Last(1) > Exptyp'Last(1) or else
6655 elsif Is_Constrained
(Exptyp
) then
6657 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
6667 L_Index
:= First_Index
(T_Typ
);
6668 R_Index
:= First_Index
(Exptyp
);
6670 for Indx
in 1 .. Ndims
loop
6671 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
6673 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
6675 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
6676 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
6678 -- Deal with compile time length check. Note that we
6679 -- skip this in the access case, because the access
6680 -- value may be null, so we cannot know statically.
6683 Subtypes_Statically_Match
6684 (Etype
(L_Index
), Etype
(R_Index
))
6686 -- If the target type is constrained then we
6687 -- have to check for exact equality of bounds
6688 -- (required for qualified expressions).
6690 if Is_Constrained
(T_Typ
) then
6693 Range_Equal_E_Cond
(Exptyp
, T_Typ
, Indx
));
6697 (Cond
, Range_E_Cond
(Exptyp
, T_Typ
, Indx
));
6708 -- Handle cases where we do not get a usable actual subtype that
6709 -- is constrained. This happens for example in the function call
6710 -- and explicit dereference cases. In these cases, we have to get
6711 -- the length or range from the expression itself, making sure we
6712 -- do not evaluate it more than once.
6714 -- Here Ck_Node is the original expression, or more properly the
6715 -- result of applying Duplicate_Expr to the original tree,
6716 -- forcing the result to be a name.
6720 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
6723 -- Build the condition for the explicit dereference case
6725 for Indx
in 1 .. Ndims
loop
6727 (Cond
, Range_N_Cond
(Ck_Node
, T_Typ
, Indx
));
6734 -- For a conversion to an unconstrained array type, generate an
6735 -- Action to check that the bounds of the source value are within
6736 -- the constraints imposed by the target type (RM 4.6(38)). No
6737 -- check is needed for a conversion to an access to unconstrained
6738 -- array type, as 4.6(24.15/2) requires the designated subtypes
6739 -- of the two access types to statically match.
6741 if Nkind
(Parent
(Ck_Node
)) = N_Type_Conversion
6742 and then not Do_Access
6745 Opnd_Index
: Node_Id
;
6746 Targ_Index
: Node_Id
;
6747 Opnd_Range
: Node_Id
;
6750 Opnd_Index
:= First_Index
(Get_Actual_Subtype
(Ck_Node
));
6751 Targ_Index
:= First_Index
(T_Typ
);
6753 while Present
(Opnd_Index
) loop
6755 -- If the index is a range, use its bounds. If it is an
6756 -- entity (as will be the case if it is a named subtype
6757 -- or an itype created for a slice) retrieve its range.
6759 if Is_Entity_Name
(Opnd_Index
)
6760 and then Is_Type
(Entity
(Opnd_Index
))
6762 Opnd_Range
:= Scalar_Range
(Entity
(Opnd_Index
));
6764 Opnd_Range
:= Opnd_Index
;
6767 if Nkind
(Opnd_Range
) = N_Range
then
6769 (Low_Bound
(Opnd_Range
), Etype
(Targ_Index
))
6772 (High_Bound
(Opnd_Range
), Etype
(Targ_Index
))
6776 -- If null range, no check needed
6779 Compile_Time_Known_Value
(High_Bound
(Opnd_Range
))
6781 Compile_Time_Known_Value
(Low_Bound
(Opnd_Range
))
6783 Expr_Value
(High_Bound
(Opnd_Range
)) <
6784 Expr_Value
(Low_Bound
(Opnd_Range
))
6788 elsif Is_Out_Of_Range
6789 (Low_Bound
(Opnd_Range
), Etype
(Targ_Index
))
6792 (High_Bound
(Opnd_Range
), Etype
(Targ_Index
))
6795 (Compile_Time_Constraint_Error
6796 (Wnode
, "value out of range of}?", T_Typ
));
6802 (Opnd_Range
, Etype
(Targ_Index
)));
6806 Next_Index
(Opnd_Index
);
6807 Next_Index
(Targ_Index
);
6814 -- Construct the test and insert into the tree
6816 if Present
(Cond
) then
6818 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
6822 (Make_Raise_Constraint_Error
(Loc
,
6824 Reason
=> CE_Range_Check_Failed
));
6828 end Selected_Range_Checks
;
6830 -------------------------------
6831 -- Storage_Checks_Suppressed --
6832 -------------------------------
6834 function Storage_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6836 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
6837 return Is_Check_Suppressed
(E
, Storage_Check
);
6839 return Scope_Suppress
(Storage_Check
);
6841 end Storage_Checks_Suppressed
;
6843 ---------------------------
6844 -- Tag_Checks_Suppressed --
6845 ---------------------------
6847 function Tag_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6850 if Kill_Tag_Checks
(E
) then
6852 elsif Checks_May_Be_Suppressed
(E
) then
6853 return Is_Check_Suppressed
(E
, Tag_Check
);
6857 return Scope_Suppress
(Tag_Check
);
6858 end Tag_Checks_Suppressed
;
6860 --------------------------
6861 -- Validity_Check_Range --
6862 --------------------------
6864 procedure Validity_Check_Range
(N
: Node_Id
) is
6866 if Validity_Checks_On
and Validity_Check_Operands
then
6867 if Nkind
(N
) = N_Range
then
6868 Ensure_Valid
(Low_Bound
(N
));
6869 Ensure_Valid
(High_Bound
(N
));
6872 end Validity_Check_Range
;
6874 --------------------------------
6875 -- Validity_Checks_Suppressed --
6876 --------------------------------
6878 function Validity_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6880 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
6881 return Is_Check_Suppressed
(E
, Validity_Check
);
6883 return Scope_Suppress
(Validity_Check
);
6885 end Validity_Checks_Suppressed
;