1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2004 Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 with Atree
; use Atree
;
28 with Debug
; use Debug
;
29 with Einfo
; use Einfo
;
30 with Errout
; use Errout
;
31 with Exp_Ch2
; use Exp_Ch2
;
32 with Exp_Util
; use Exp_Util
;
33 with Elists
; use Elists
;
34 with Eval_Fat
; use Eval_Fat
;
35 with Freeze
; use Freeze
;
37 with Nlists
; use Nlists
;
38 with Nmake
; use Nmake
;
40 with Output
; use Output
;
41 with Restrict
; use Restrict
;
42 with Rident
; use Rident
;
43 with Rtsfind
; use Rtsfind
;
45 with Sem_Eval
; use Sem_Eval
;
46 with Sem_Ch3
; use Sem_Ch3
;
47 with Sem_Ch8
; use Sem_Ch8
;
48 with Sem_Res
; use Sem_Res
;
49 with Sem_Util
; use Sem_Util
;
50 with Sem_Warn
; use Sem_Warn
;
51 with Sinfo
; use Sinfo
;
52 with Sinput
; use Sinput
;
53 with Snames
; use Snames
;
54 with Sprint
; use Sprint
;
55 with Stand
; use Stand
;
56 with Targparm
; use Targparm
;
57 with Tbuild
; use Tbuild
;
58 with Ttypes
; use Ttypes
;
59 with Urealp
; use Urealp
;
60 with Validsw
; use Validsw
;
62 package body Checks
is
64 -- General note: many of these routines are concerned with generating
65 -- checking code to make sure that constraint error is raised at runtime.
66 -- Clearly this code is only needed if the expander is active, since
67 -- otherwise we will not be generating code or going into the runtime
70 -- We therefore disconnect most of these checks if the expander is
71 -- inactive. This has the additional benefit that we do not need to
72 -- worry about the tree being messed up by previous errors (since errors
73 -- turn off expansion anyway).
75 -- There are a few exceptions to the above rule. For instance routines
76 -- such as Apply_Scalar_Range_Check that do not insert any code can be
77 -- safely called even when the Expander is inactive (but Errors_Detected
78 -- is 0). The benefit of executing this code when expansion is off, is
79 -- the ability to emit constraint error warning for static expressions
80 -- even when we are not generating code.
82 -------------------------------------
83 -- Suppression of Redundant Checks --
84 -------------------------------------
86 -- This unit implements a limited circuit for removal of redundant
87 -- checks. The processing is based on a tracing of simple sequential
88 -- flow. For any sequence of statements, we save expressions that are
89 -- marked to be checked, and then if the same expression appears later
90 -- with the same check, then under certain circumstances, the second
91 -- check can be suppressed.
93 -- Basically, we can suppress the check if we know for certain that
94 -- the previous expression has been elaborated (together with its
95 -- check), and we know that the exception frame is the same, and that
96 -- nothing has happened to change the result of the exception.
98 -- Let us examine each of these three conditions in turn to describe
99 -- how we ensure that this condition is met.
101 -- First, we need to know for certain that the previous expression has
102 -- been executed. This is done principly by the mechanism of calling
103 -- Conditional_Statements_Begin at the start of any statement sequence
104 -- and Conditional_Statements_End at the end. The End call causes all
105 -- checks remembered since the Begin call to be discarded. This does
106 -- miss a few cases, notably the case of a nested BEGIN-END block with
107 -- no exception handlers. But the important thing is to be conservative.
108 -- The other protection is that all checks are discarded if a label
109 -- is encountered, since then the assumption of sequential execution
110 -- is violated, and we don't know enough about the flow.
112 -- Second, we need to know that the exception frame is the same. We
113 -- do this by killing all remembered checks when we enter a new frame.
114 -- Again, that's over-conservative, but generally the cases we can help
115 -- with are pretty local anyway (like the body of a loop for example).
117 -- Third, we must be sure to forget any checks which are no longer valid.
118 -- This is done by two mechanisms, first the Kill_Checks_Variable call is
119 -- used to note any changes to local variables. We only attempt to deal
120 -- with checks involving local variables, so we do not need to worry
121 -- about global variables. Second, a call to any non-global procedure
122 -- causes us to abandon all stored checks, since such a all may affect
123 -- the values of any local variables.
125 -- The following define the data structures used to deal with remembering
126 -- checks so that redundant checks can be eliminated as described above.
128 -- Right now, the only expressions that we deal with are of the form of
129 -- simple local objects (either declared locally, or IN parameters) or
130 -- such objects plus/minus a compile time known constant. We can do
131 -- more later on if it seems worthwhile, but this catches many simple
132 -- cases in practice.
134 -- The following record type reflects a single saved check. An entry
135 -- is made in the stack of saved checks if and only if the expression
136 -- has been elaborated with the indicated checks.
138 type Saved_Check
is record
140 -- Set True if entry is killed by Kill_Checks
143 -- The entity involved in the expression that is checked
146 -- A compile time value indicating the result of adding or
147 -- subtracting a compile time value. This value is to be
148 -- added to the value of the Entity. A value of zero is
149 -- used for the case of a simple entity reference.
151 Check_Type
: Character;
152 -- This is set to 'R' for a range check (in which case Target_Type
153 -- is set to the target type for the range check) or to 'O' for an
154 -- overflow check (in which case Target_Type is set to Empty).
156 Target_Type
: Entity_Id
;
157 -- Used only if Do_Range_Check is set. Records the target type for
158 -- the check. We need this, because a check is a duplicate only if
159 -- it has a the same target type (or more accurately one with a
160 -- range that is smaller or equal to the stored target type of a
164 -- The following table keeps track of saved checks. Rather than use an
165 -- extensible table. We just use a table of fixed size, and we discard
166 -- any saved checks that do not fit. That's very unlikely to happen and
167 -- this is only an optimization in any case.
169 Saved_Checks
: array (Int
range 1 .. 200) of Saved_Check
;
170 -- Array of saved checks
172 Num_Saved_Checks
: Nat
:= 0;
173 -- Number of saved checks
175 -- The following stack keeps track of statement ranges. It is treated
176 -- as a stack. When Conditional_Statements_Begin is called, an entry
177 -- is pushed onto this stack containing the value of Num_Saved_Checks
178 -- at the time of the call. Then when Conditional_Statements_End is
179 -- called, this value is popped off and used to reset Num_Saved_Checks.
181 -- Note: again, this is a fixed length stack with a size that should
182 -- always be fine. If the value of the stack pointer goes above the
183 -- limit, then we just forget all saved checks.
185 Saved_Checks_Stack
: array (Int
range 1 .. 100) of Nat
;
186 Saved_Checks_TOS
: Nat
:= 0;
188 -----------------------
189 -- Local Subprograms --
190 -----------------------
192 procedure Apply_Float_Conversion_Check
194 Target_Typ
: Entity_Id
);
195 -- The checks on a conversion from a floating-point type to an integer
196 -- type are delicate. They have to be performed before conversion, they
197 -- have to raise an exception when the operand is a NaN, and rounding must
198 -- be taken into account to determine the safe bounds of the operand.
200 procedure Apply_Selected_Length_Checks
202 Target_Typ
: Entity_Id
;
203 Source_Typ
: Entity_Id
;
204 Do_Static
: Boolean);
205 -- This is the subprogram that does all the work for Apply_Length_Check
206 -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as
207 -- described for the above routines. The Do_Static flag indicates that
208 -- only a static check is to be done.
210 procedure Apply_Selected_Range_Checks
212 Target_Typ
: Entity_Id
;
213 Source_Typ
: Entity_Id
;
214 Do_Static
: Boolean);
215 -- This is the subprogram that does all the work for Apply_Range_Check.
216 -- Expr, Target_Typ and Source_Typ are as described for the above
217 -- routine. The Do_Static flag indicates that only a static check is
222 Check_Type
: Character;
223 Target_Type
: Entity_Id
;
224 Entry_OK
: out Boolean;
228 -- This routine is used by Enable_Range_Check and Enable_Overflow_Check
229 -- to see if a check is of the form for optimization, and if so, to see
230 -- if it has already been performed. Expr is the expression to check,
231 -- and Check_Type is 'R' for a range check, 'O' for an overflow check.
232 -- Target_Type is the target type for a range check, and Empty for an
233 -- overflow check. If the entry is not of the form for optimization,
234 -- then Entry_OK is set to False, and the remaining out parameters
235 -- are undefined. If the entry is OK, then Ent/Ofs are set to the
236 -- entity and offset from the expression. Check_Num is the number of
237 -- a matching saved entry in Saved_Checks, or zero if no such entry
240 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
;
241 -- If a discriminal is used in constraining a prival, Return reference
242 -- to the discriminal of the protected body (which renames the parameter
243 -- of the enclosing protected operation). This clumsy transformation is
244 -- needed because privals are created too late and their actual subtypes
245 -- are not available when analysing the bodies of the protected operations.
246 -- To be cleaned up???
248 function Guard_Access
251 Ck_Node
: Node_Id
) return Node_Id
;
252 -- In the access type case, guard the test with a test to ensure
253 -- that the access value is non-null, since the checks do not
254 -- not apply to null access values.
256 procedure Install_Null_Excluding_Check
(N
: Node_Id
);
257 -- Determines whether an access node requires a runtime access check and
258 -- if so inserts the appropriate run-time check
260 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
);
261 -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the
262 -- Constraint_Error node.
264 function Selected_Length_Checks
266 Target_Typ
: Entity_Id
;
267 Source_Typ
: Entity_Id
;
268 Warn_Node
: Node_Id
) return Check_Result
;
269 -- Like Apply_Selected_Length_Checks, except it doesn't modify
270 -- anything, just returns a list of nodes as described in the spec of
271 -- this package for the Range_Check function.
273 function Selected_Range_Checks
275 Target_Typ
: Entity_Id
;
276 Source_Typ
: Entity_Id
;
277 Warn_Node
: Node_Id
) return Check_Result
;
278 -- Like Apply_Selected_Range_Checks, except it doesn't modify anything,
279 -- just returns a list of nodes as described in the spec of this package
280 -- for the Range_Check function.
282 ------------------------------
283 -- Access_Checks_Suppressed --
284 ------------------------------
286 function Access_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
288 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
289 return Is_Check_Suppressed
(E
, Access_Check
);
291 return Scope_Suppress
(Access_Check
);
293 end Access_Checks_Suppressed
;
295 -------------------------------------
296 -- Accessibility_Checks_Suppressed --
297 -------------------------------------
299 function Accessibility_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
301 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
302 return Is_Check_Suppressed
(E
, Accessibility_Check
);
304 return Scope_Suppress
(Accessibility_Check
);
306 end Accessibility_Checks_Suppressed
;
308 -------------------------
309 -- Append_Range_Checks --
310 -------------------------
312 procedure Append_Range_Checks
313 (Checks
: Check_Result
;
315 Suppress_Typ
: Entity_Id
;
316 Static_Sloc
: Source_Ptr
;
319 Internal_Flag_Node
: constant Node_Id
:= Flag_Node
;
320 Internal_Static_Sloc
: constant Source_Ptr
:= Static_Sloc
;
322 Checks_On
: constant Boolean :=
323 (not Index_Checks_Suppressed
(Suppress_Typ
))
325 (not Range_Checks_Suppressed
(Suppress_Typ
));
328 -- For now we just return if Checks_On is false, however this should
329 -- be enhanced to check for an always True value in the condition
330 -- and to generate a compilation warning???
332 if not Checks_On
then
337 exit when No
(Checks
(J
));
339 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
340 and then Present
(Condition
(Checks
(J
)))
342 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
343 Append_To
(Stmts
, Checks
(J
));
344 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
350 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
351 Reason
=> CE_Range_Check_Failed
));
354 end Append_Range_Checks
;
356 ------------------------
357 -- Apply_Access_Check --
358 ------------------------
360 procedure Apply_Access_Check
(N
: Node_Id
) is
361 P
: constant Node_Id
:= Prefix
(N
);
364 if Inside_A_Generic
then
368 if Is_Entity_Name
(P
) then
369 Check_Unset_Reference
(P
);
372 -- We do not need access checks if prefix is known to be non-null
374 if Known_Non_Null
(P
) then
377 -- We do not need access checks if they are suppressed on the type
379 elsif Access_Checks_Suppressed
(Etype
(P
)) then
382 -- We do not need checks if we are not generating code (i.e. the
383 -- expander is not active). This is not just an optimization, there
384 -- are cases (e.g. with pragma Debug) where generating the checks
385 -- can cause real trouble).
387 elsif not Expander_Active
then
391 -- Case where P is an entity name
393 if Is_Entity_Name
(P
) then
395 Ent
: constant Entity_Id
:= Entity
(P
);
398 if Access_Checks_Suppressed
(Ent
) then
402 -- Otherwise we are going to generate an access check, and
403 -- are we have done it, the entity will now be known non null
404 -- But we have to check for safe sequential semantics here!
406 if Safe_To_Capture_Value
(N
, Ent
) then
407 Set_Is_Known_Non_Null
(Ent
);
412 -- Access check is required
414 Install_Null_Excluding_Check
(P
);
415 end Apply_Access_Check
;
417 -------------------------------
418 -- Apply_Accessibility_Check --
419 -------------------------------
421 procedure Apply_Accessibility_Check
(N
: Node_Id
; Typ
: Entity_Id
) is
422 Loc
: constant Source_Ptr
:= Sloc
(N
);
423 Param_Ent
: constant Entity_Id
:= Param_Entity
(N
);
424 Param_Level
: Node_Id
;
425 Type_Level
: Node_Id
;
428 if Inside_A_Generic
then
431 -- Only apply the run-time check if the access parameter
432 -- has an associated extra access level parameter and
433 -- when the level of the type is less deep than the level
434 -- of the access parameter.
436 elsif Present
(Param_Ent
)
437 and then Present
(Extra_Accessibility
(Param_Ent
))
438 and then UI_Gt
(Object_Access_Level
(N
),
439 Type_Access_Level
(Typ
))
440 and then not Accessibility_Checks_Suppressed
(Param_Ent
)
441 and then not Accessibility_Checks_Suppressed
(Typ
)
444 New_Occurrence_Of
(Extra_Accessibility
(Param_Ent
), Loc
);
447 Make_Integer_Literal
(Loc
, Type_Access_Level
(Typ
));
449 -- Raise Program_Error if the accessibility level of the
450 -- the access parameter is deeper than the level of the
451 -- target access type.
454 Make_Raise_Program_Error
(Loc
,
457 Left_Opnd
=> Param_Level
,
458 Right_Opnd
=> Type_Level
),
459 Reason
=> PE_Accessibility_Check_Failed
));
461 Analyze_And_Resolve
(N
);
463 end Apply_Accessibility_Check
;
465 ---------------------------
466 -- Apply_Alignment_Check --
467 ---------------------------
469 procedure Apply_Alignment_Check
(E
: Entity_Id
; N
: Node_Id
) is
470 AC
: constant Node_Id
:= Address_Clause
(E
);
474 Alignment_Required
: constant Boolean := Maximum_Alignment
> 1;
475 -- Constant to show whether target requires alignment checks
478 -- See if check needed. Note that we never need a check if the
479 -- maximum alignment is one, since the check will always succeed
482 or else not Check_Address_Alignment
(AC
)
483 or else not Alignment_Required
489 Expr
:= Expression
(AC
);
491 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
then
492 Expr
:= Expression
(Expr
);
494 elsif Nkind
(Expr
) = N_Function_Call
495 and then Is_RTE
(Entity
(Name
(Expr
)), RE_To_Address
)
497 Expr
:= First
(Parameter_Associations
(Expr
));
499 if Nkind
(Expr
) = N_Parameter_Association
then
500 Expr
:= Explicit_Actual_Parameter
(Expr
);
504 -- Here Expr is the address value. See if we know that the
505 -- value is unacceptable at compile time.
507 if Compile_Time_Known_Value
(Expr
)
508 and then Known_Alignment
(E
)
510 if Expr_Value
(Expr
) mod Alignment
(E
) /= 0 then
512 Make_Raise_Program_Error
(Loc
,
513 Reason
=> PE_Misaligned_Address_Value
));
515 ("?specified address for& not " &
516 "consistent with alignment ('R'M 13.3(27))", Expr
, E
);
519 -- Here we do not know if the value is acceptable, generate
520 -- code to raise PE if alignment is inappropriate.
523 -- Skip generation of this code if we don't want elab code
525 if not Restriction_Active
(No_Elaboration_Code
) then
526 Insert_After_And_Analyze
(N
,
527 Make_Raise_Program_Error
(Loc
,
534 (RTE
(RE_Integer_Address
),
535 Duplicate_Subexpr_No_Checks
(Expr
)),
537 Make_Attribute_Reference
(Loc
,
538 Prefix
=> New_Occurrence_Of
(E
, Loc
),
539 Attribute_Name
=> Name_Alignment
)),
540 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
541 Reason
=> PE_Misaligned_Address_Value
),
542 Suppress
=> All_Checks
);
549 when RE_Not_Available
=>
551 end Apply_Alignment_Check
;
553 -------------------------------------
554 -- Apply_Arithmetic_Overflow_Check --
555 -------------------------------------
557 -- This routine is called only if the type is an integer type, and
558 -- a software arithmetic overflow check must be performed for op
559 -- (add, subtract, multiply). The check is performed only if
560 -- Software_Overflow_Checking is enabled and Do_Overflow_Check
561 -- is set. In this case we expand the operation into a more complex
562 -- sequence of tests that ensures that overflow is properly caught.
564 procedure Apply_Arithmetic_Overflow_Check
(N
: Node_Id
) is
565 Loc
: constant Source_Ptr
:= Sloc
(N
);
566 Typ
: constant Entity_Id
:= Etype
(N
);
567 Rtyp
: constant Entity_Id
:= Root_Type
(Typ
);
568 Siz
: constant Int
:= UI_To_Int
(Esize
(Rtyp
));
569 Dsiz
: constant Int
:= Siz
* 2;
576 -- Skip this if overflow checks are done in back end, or the overflow
577 -- flag is not set anyway, or we are not doing code expansion.
579 if Backend_Overflow_Checks_On_Target
580 or else not Do_Overflow_Check
(N
)
581 or else not Expander_Active
586 -- Otherwise, we generate the full general code for front end overflow
587 -- detection, which works by doing arithmetic in a larger type:
593 -- Typ (Checktyp (x) op Checktyp (y));
595 -- where Typ is the type of the original expression, and Checktyp is
596 -- an integer type of sufficient length to hold the largest possible
599 -- In the case where check type exceeds the size of Long_Long_Integer,
600 -- we use a different approach, expanding to:
602 -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y)))
604 -- where xxx is Add, Multiply or Subtract as appropriate
606 -- Find check type if one exists
608 if Dsiz
<= Standard_Integer_Size
then
609 Ctyp
:= Standard_Integer
;
611 elsif Dsiz
<= Standard_Long_Long_Integer_Size
then
612 Ctyp
:= Standard_Long_Long_Integer
;
614 -- No check type exists, use runtime call
617 if Nkind
(N
) = N_Op_Add
then
618 Cent
:= RE_Add_With_Ovflo_Check
;
620 elsif Nkind
(N
) = N_Op_Multiply
then
621 Cent
:= RE_Multiply_With_Ovflo_Check
;
624 pragma Assert
(Nkind
(N
) = N_Op_Subtract
);
625 Cent
:= RE_Subtract_With_Ovflo_Check
;
630 Make_Function_Call
(Loc
,
631 Name
=> New_Reference_To
(RTE
(Cent
), Loc
),
632 Parameter_Associations
=> New_List
(
633 OK_Convert_To
(RTE
(RE_Integer_64
), Left_Opnd
(N
)),
634 OK_Convert_To
(RTE
(RE_Integer_64
), Right_Opnd
(N
))))));
636 Analyze_And_Resolve
(N
, Typ
);
640 -- If we fall through, we have the case where we do the arithmetic in
641 -- the next higher type and get the check by conversion. In these cases
642 -- Ctyp is set to the type to be used as the check type.
644 Opnod
:= Relocate_Node
(N
);
646 Opnd
:= OK_Convert_To
(Ctyp
, Left_Opnd
(Opnod
));
649 Set_Etype
(Opnd
, Ctyp
);
650 Set_Analyzed
(Opnd
, True);
651 Set_Left_Opnd
(Opnod
, Opnd
);
653 Opnd
:= OK_Convert_To
(Ctyp
, Right_Opnd
(Opnod
));
656 Set_Etype
(Opnd
, Ctyp
);
657 Set_Analyzed
(Opnd
, True);
658 Set_Right_Opnd
(Opnod
, Opnd
);
660 -- The type of the operation changes to the base type of the check
661 -- type, and we reset the overflow check indication, since clearly
662 -- no overflow is possible now that we are using a double length
663 -- type. We also set the Analyzed flag to avoid a recursive attempt
664 -- to expand the node.
666 Set_Etype
(Opnod
, Base_Type
(Ctyp
));
667 Set_Do_Overflow_Check
(Opnod
, False);
668 Set_Analyzed
(Opnod
, True);
670 -- Now build the outer conversion
672 Opnd
:= OK_Convert_To
(Typ
, Opnod
);
674 Set_Etype
(Opnd
, Typ
);
676 -- In the discrete type case, we directly generate the range check
677 -- for the outer operand. This range check will implement the required
680 if Is_Discrete_Type
(Typ
) then
682 Generate_Range_Check
(Expression
(N
), Typ
, CE_Overflow_Check_Failed
);
684 -- For other types, we enable overflow checking on the conversion,
685 -- after setting the node as analyzed to prevent recursive attempts
686 -- to expand the conversion node.
689 Set_Analyzed
(Opnd
, True);
690 Enable_Overflow_Check
(Opnd
);
695 when RE_Not_Available
=>
697 end Apply_Arithmetic_Overflow_Check
;
699 ----------------------------
700 -- Apply_Array_Size_Check --
701 ----------------------------
703 -- Note: Really of course this entre check should be in the backend,
704 -- and perhaps this is not quite the right value, but it is good
705 -- enough to catch the normal cases (and the relevant ACVC tests!)
707 -- The situation is as follows. In GNAT 3 (GCC 2.x), the size in bits
708 -- is computed in 32 bits without an overflow check. That's a real
709 -- problem for Ada. So what we do in GNAT 3 is to approximate the
710 -- size of an array by manually multiplying the element size by the
711 -- number of elements, and comparing that against the allowed limits.
713 -- In GNAT 5, the size in byte is still computed in 32 bits without
714 -- an overflow check in the dynamic case, but the size in bits is
715 -- computed in 64 bits. We assume that's good enough, so we use the
716 -- size in bits for the test.
718 procedure Apply_Array_Size_Check
(N
: Node_Id
; Typ
: Entity_Id
) is
719 Loc
: constant Source_Ptr
:= Sloc
(N
);
720 Ctyp
: constant Entity_Id
:= Component_Type
(Typ
);
721 Ent
: constant Entity_Id
:= Defining_Identifier
(N
);
733 Static
: Boolean := True;
734 -- Set false if any index subtye bound is non-static
736 Umark
: constant Uintp
.Save_Mark
:= Uintp
.Mark
;
737 -- We can throw away all the Uint computations here, since they are
738 -- done only to generate boolean test results.
741 -- Size to check against
743 function Is_Address_Or_Import
(Decl
: Node_Id
) return Boolean;
744 -- Determines if Decl is an address clause or Import/Interface pragma
745 -- that references the defining identifier of the current declaration.
747 --------------------------
748 -- Is_Address_Or_Import --
749 --------------------------
751 function Is_Address_Or_Import
(Decl
: Node_Id
) return Boolean is
753 if Nkind
(Decl
) = N_At_Clause
then
754 return Chars
(Identifier
(Decl
)) = Chars
(Ent
);
756 elsif Nkind
(Decl
) = N_Attribute_Definition_Clause
then
758 Chars
(Decl
) = Name_Address
760 Nkind
(Name
(Decl
)) = N_Identifier
762 Chars
(Name
(Decl
)) = Chars
(Ent
);
764 elsif Nkind
(Decl
) = N_Pragma
then
765 if (Chars
(Decl
) = Name_Import
767 Chars
(Decl
) = Name_Interface
)
768 and then Present
(Pragma_Argument_Associations
(Decl
))
771 F
: constant Node_Id
:=
772 First
(Pragma_Argument_Associations
(Decl
));
780 Nkind
(Expression
(Next
(F
))) = N_Identifier
782 Chars
(Expression
(Next
(F
))) = Chars
(Ent
);
792 end Is_Address_Or_Import
;
794 -- Start of processing for Apply_Array_Size_Check
797 -- No need for a check if not expanding
799 if not Expander_Active
then
803 -- No need for a check if checks are suppressed
805 if Storage_Checks_Suppressed
(Typ
) then
809 -- It is pointless to insert this check inside an init proc, because
810 -- that's too late, we have already built the object to be the right
811 -- size, and if it's too large, too bad!
813 if Inside_Init_Proc
then
817 -- Look head for pragma interface/import or address clause applying
818 -- to this entity. If found, we suppress the check entirely. For now
819 -- we only look ahead 20 declarations to stop this becoming too slow
820 -- Note that eventually this whole routine gets moved to gigi.
823 for Ctr
in 1 .. 20 loop
827 if Is_Address_Or_Import
(Decl
) then
834 if Opt
.GCC_Version
= 3 then
836 -- No problem if size is known at compile time (even if the front
837 -- end does not know it) because the back end does do overflow
838 -- checking on the size in bytes if it is compile time known.
840 if Size_Known_At_Compile_Time
(Typ
) then
845 -- Following code is temporarily deleted, since GCC 3 is returning
846 -- zero for size in bits of large dynamic arrays. ???
848 -- -- Otherwise we check for the size in bits exceeding 2**31-1 * 8.
849 -- -- This is the case in which we could end up with problems from
850 -- -- an unnoticed overflow in computing the size in bytes
852 -- Check_Siz := (Uint_2 ** 31 - Uint_1) * Uint_8;
855 -- Make_Attribute_Reference (Loc,
856 -- Prefix => New_Occurrence_Of (Typ, Loc),
857 -- Attribute_Name => Name_Size);
859 -- GCC 2 case (for now this is for GCC 3 dynamic case as well)
862 -- First step is to calculate the maximum number of elements. For
863 -- this calculation, we use the actual size of the subtype if it is
864 -- static, and if a bound of a subtype is non-static, we go to the
865 -- bound of the base type.
868 Indx
:= First_Index
(Typ
);
869 while Present
(Indx
) loop
870 Xtyp
:= Etype
(Indx
);
871 Lo
:= Type_Low_Bound
(Xtyp
);
872 Hi
:= Type_High_Bound
(Xtyp
);
874 -- If any bound raises constraint error, we will never get this
875 -- far, so there is no need to generate any kind of check.
877 if Raises_Constraint_Error
(Lo
)
879 Raises_Constraint_Error
(Hi
)
881 Uintp
.Release
(Umark
);
885 -- Otherwise get bounds values
887 if Is_Static_Expression
(Lo
) then
888 Lob
:= Expr_Value
(Lo
);
890 Lob
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Xtyp
)));
894 if Is_Static_Expression
(Hi
) then
895 Hib
:= Expr_Value
(Hi
);
897 Hib
:= Expr_Value
(Type_High_Bound
(Base_Type
(Xtyp
)));
901 Siz
:= Siz
* UI_Max
(Hib
- Lob
+ 1, Uint_0
);
905 -- Compute the limit against which we want to check. For subprograms,
906 -- where the array will go on the stack, we use 8*2**24, which (in
907 -- bits) is the size of a 16 megabyte array.
909 if Is_Subprogram
(Scope
(Ent
)) then
910 Check_Siz
:= Uint_2
** 27;
912 Check_Siz
:= Uint_2
** 31;
915 -- If we have all static bounds and Siz is too large, then we know
916 -- we know we have a storage error right now, so generate message
918 if Static
and then Siz
>= Check_Siz
then
920 Make_Raise_Storage_Error
(Loc
,
921 Reason
=> SE_Object_Too_Large
));
922 Error_Msg_N
("?Storage_Error will be raised at run-time", N
);
923 Uintp
.Release
(Umark
);
927 -- Case of component size known at compile time. If the array
928 -- size is definitely in range, then we do not need a check.
930 if Known_Esize
(Ctyp
)
931 and then Siz
* Esize
(Ctyp
) < Check_Siz
933 Uintp
.Release
(Umark
);
937 -- Here if a dynamic check is required
939 -- What we do is to build an expression for the size of the array,
940 -- which is computed as the 'Size of the array component, times
941 -- the size of each dimension.
943 Uintp
.Release
(Umark
);
946 Make_Attribute_Reference
(Loc
,
947 Prefix
=> New_Occurrence_Of
(Ctyp
, Loc
),
948 Attribute_Name
=> Name_Size
);
950 Indx
:= First_Index
(Typ
);
951 for J
in 1 .. Number_Dimensions
(Typ
) loop
952 if Sloc
(Etype
(Indx
)) = Sloc
(N
) then
953 Ensure_Defined
(Etype
(Indx
), N
);
957 Make_Op_Multiply
(Loc
,
960 Make_Attribute_Reference
(Loc
,
961 Prefix
=> New_Occurrence_Of
(Typ
, Loc
),
962 Attribute_Name
=> Name_Length
,
963 Expressions
=> New_List
(
964 Make_Integer_Literal
(Loc
, J
))));
969 -- Common code to actually emit the check
972 Make_Raise_Storage_Error
(Loc
,
977 Make_Integer_Literal
(Loc
,
978 Intval
=> Check_Siz
)),
979 Reason
=> SE_Object_Too_Large
);
981 Set_Size_Check_Code
(Defining_Identifier
(N
), Code
);
982 Insert_Action
(N
, Code
, Suppress
=> All_Checks
);
983 end Apply_Array_Size_Check
;
985 ----------------------------
986 -- Apply_Constraint_Check --
987 ----------------------------
989 procedure Apply_Constraint_Check
992 No_Sliding
: Boolean := False)
994 Desig_Typ
: Entity_Id
;
997 if Inside_A_Generic
then
1000 elsif Is_Scalar_Type
(Typ
) then
1001 Apply_Scalar_Range_Check
(N
, Typ
);
1003 elsif Is_Array_Type
(Typ
) then
1005 -- A useful optimization: an aggregate with only an Others clause
1006 -- always has the right bounds.
1008 if Nkind
(N
) = N_Aggregate
1009 and then No
(Expressions
(N
))
1011 (First
(Choices
(First
(Component_Associations
(N
)))))
1017 if Is_Constrained
(Typ
) then
1018 Apply_Length_Check
(N
, Typ
);
1021 Apply_Range_Check
(N
, Typ
);
1024 Apply_Range_Check
(N
, Typ
);
1027 elsif (Is_Record_Type
(Typ
)
1028 or else Is_Private_Type
(Typ
))
1029 and then Has_Discriminants
(Base_Type
(Typ
))
1030 and then Is_Constrained
(Typ
)
1032 Apply_Discriminant_Check
(N
, Typ
);
1034 elsif Is_Access_Type
(Typ
) then
1036 Desig_Typ
:= Designated_Type
(Typ
);
1038 -- No checks necessary if expression statically null
1040 if Nkind
(N
) = N_Null
then
1043 -- No sliding possible on access to arrays
1045 elsif Is_Array_Type
(Desig_Typ
) then
1046 if Is_Constrained
(Desig_Typ
) then
1047 Apply_Length_Check
(N
, Typ
);
1050 Apply_Range_Check
(N
, Typ
);
1052 elsif Has_Discriminants
(Base_Type
(Desig_Typ
))
1053 and then Is_Constrained
(Desig_Typ
)
1055 Apply_Discriminant_Check
(N
, Typ
);
1058 if Can_Never_Be_Null
(Typ
)
1059 and then not Can_Never_Be_Null
(Etype
(N
))
1061 Install_Null_Excluding_Check
(N
);
1064 end Apply_Constraint_Check
;
1066 ------------------------------
1067 -- Apply_Discriminant_Check --
1068 ------------------------------
1070 procedure Apply_Discriminant_Check
1073 Lhs
: Node_Id
:= Empty
)
1075 Loc
: constant Source_Ptr
:= Sloc
(N
);
1076 Do_Access
: constant Boolean := Is_Access_Type
(Typ
);
1077 S_Typ
: Entity_Id
:= Etype
(N
);
1081 function Is_Aliased_Unconstrained_Component
return Boolean;
1082 -- It is possible for an aliased component to have a nominal
1083 -- unconstrained subtype (through instantiation). If this is a
1084 -- discriminated component assigned in the expansion of an aggregate
1085 -- in an initialization, the check must be suppressed. This unusual
1086 -- situation requires a predicate of its own (see 7503-008).
1088 ----------------------------------------
1089 -- Is_Aliased_Unconstrained_Component --
1090 ----------------------------------------
1092 function Is_Aliased_Unconstrained_Component
return Boolean is
1097 if Nkind
(Lhs
) /= N_Selected_Component
then
1100 Comp
:= Entity
(Selector_Name
(Lhs
));
1101 Pref
:= Prefix
(Lhs
);
1104 if Ekind
(Comp
) /= E_Component
1105 or else not Is_Aliased
(Comp
)
1110 return not Comes_From_Source
(Pref
)
1111 and then In_Instance
1112 and then not Is_Constrained
(Etype
(Comp
));
1113 end Is_Aliased_Unconstrained_Component
;
1115 -- Start of processing for Apply_Discriminant_Check
1119 T_Typ
:= Designated_Type
(Typ
);
1124 -- Nothing to do if discriminant checks are suppressed or else no code
1125 -- is to be generated
1127 if not Expander_Active
1128 or else Discriminant_Checks_Suppressed
(T_Typ
)
1133 -- No discriminant checks necessary for access when expression
1134 -- is statically Null. This is not only an optimization, this is
1135 -- fundamental because otherwise discriminant checks may be generated
1136 -- in init procs for types containing an access to a non-frozen yet
1137 -- record, causing a deadly forward reference.
1139 -- Also, if the expression is of an access type whose designated
1140 -- type is incomplete, then the access value must be null and
1141 -- we suppress the check.
1143 if Nkind
(N
) = N_Null
then
1146 elsif Is_Access_Type
(S_Typ
) then
1147 S_Typ
:= Designated_Type
(S_Typ
);
1149 if Ekind
(S_Typ
) = E_Incomplete_Type
then
1154 -- If an assignment target is present, then we need to generate
1155 -- the actual subtype if the target is a parameter or aliased
1156 -- object with an unconstrained nominal subtype.
1159 and then (Present
(Param_Entity
(Lhs
))
1160 or else (not Is_Constrained
(T_Typ
)
1161 and then Is_Aliased_View
(Lhs
)
1162 and then not Is_Aliased_Unconstrained_Component
))
1164 T_Typ
:= Get_Actual_Subtype
(Lhs
);
1167 -- Nothing to do if the type is unconstrained (this is the case
1168 -- where the actual subtype in the RM sense of N is unconstrained
1169 -- and no check is required).
1171 if not Is_Constrained
(T_Typ
) then
1175 -- Nothing to do if the type is an Unchecked_Union
1177 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
1181 -- Suppress checks if the subtypes are the same.
1182 -- the check must be preserved in an assignment to a formal, because
1183 -- the constraint is given by the actual.
1185 if Nkind
(Original_Node
(N
)) /= N_Allocator
1187 or else not Is_Entity_Name
(Lhs
)
1188 or else No
(Param_Entity
(Lhs
)))
1191 or else (Do_Access
and then Designated_Type
(Typ
) = S_Typ
))
1192 and then not Is_Aliased_View
(Lhs
)
1197 -- We can also eliminate checks on allocators with a subtype mark
1198 -- that coincides with the context type. The context type may be a
1199 -- subtype without a constraint (common case, a generic actual).
1201 elsif Nkind
(Original_Node
(N
)) = N_Allocator
1202 and then Is_Entity_Name
(Expression
(Original_Node
(N
)))
1205 Alloc_Typ
: constant Entity_Id
:=
1206 Entity
(Expression
(Original_Node
(N
)));
1209 if Alloc_Typ
= T_Typ
1210 or else (Nkind
(Parent
(T_Typ
)) = N_Subtype_Declaration
1211 and then Is_Entity_Name
(
1212 Subtype_Indication
(Parent
(T_Typ
)))
1213 and then Alloc_Typ
= Base_Type
(T_Typ
))
1221 -- See if we have a case where the types are both constrained, and
1222 -- all the constraints are constants. In this case, we can do the
1223 -- check successfully at compile time.
1225 -- We skip this check for the case where the node is a rewritten`
1226 -- allocator, because it already carries the context subtype, and
1227 -- extracting the discriminants from the aggregate is messy.
1229 if Is_Constrained
(S_Typ
)
1230 and then Nkind
(Original_Node
(N
)) /= N_Allocator
1240 -- S_Typ may not have discriminants in the case where it is a
1241 -- private type completed by a default discriminated type. In
1242 -- that case, we need to get the constraints from the
1243 -- underlying_type. If the underlying type is unconstrained (i.e.
1244 -- has no default discriminants) no check is needed.
1246 if Has_Discriminants
(S_Typ
) then
1247 Discr
:= First_Discriminant
(S_Typ
);
1248 DconS
:= First_Elmt
(Discriminant_Constraint
(S_Typ
));
1251 Discr
:= First_Discriminant
(Underlying_Type
(S_Typ
));
1254 (Discriminant_Constraint
(Underlying_Type
(S_Typ
)));
1260 -- A further optimization: if T_Typ is derived from S_Typ
1261 -- without imposing a constraint, no check is needed.
1263 if Nkind
(Original_Node
(Parent
(T_Typ
))) =
1264 N_Full_Type_Declaration
1267 Type_Def
: constant Node_Id
:=
1269 (Original_Node
(Parent
(T_Typ
)));
1271 if Nkind
(Type_Def
) = N_Derived_Type_Definition
1272 and then Is_Entity_Name
(Subtype_Indication
(Type_Def
))
1273 and then Entity
(Subtype_Indication
(Type_Def
)) = S_Typ
1281 DconT
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
1283 while Present
(Discr
) loop
1284 ItemS
:= Node
(DconS
);
1285 ItemT
:= Node
(DconT
);
1288 not Is_OK_Static_Expression
(ItemS
)
1290 not Is_OK_Static_Expression
(ItemT
);
1292 if Expr_Value
(ItemS
) /= Expr_Value
(ItemT
) then
1293 if Do_Access
then -- needs run-time check.
1296 Apply_Compile_Time_Constraint_Error
1297 (N
, "incorrect value for discriminant&?",
1298 CE_Discriminant_Check_Failed
, Ent
=> Discr
);
1305 Next_Discriminant
(Discr
);
1314 -- Here we need a discriminant check. First build the expression
1315 -- for the comparisons of the discriminants:
1317 -- (n.disc1 /= typ.disc1) or else
1318 -- (n.disc2 /= typ.disc2) or else
1320 -- (n.discn /= typ.discn)
1322 Cond
:= Build_Discriminant_Checks
(N
, T_Typ
);
1324 -- If Lhs is set and is a parameter, then the condition is
1325 -- guarded by: lhs'constrained and then (condition built above)
1327 if Present
(Param_Entity
(Lhs
)) then
1331 Make_Attribute_Reference
(Loc
,
1332 Prefix
=> New_Occurrence_Of
(Param_Entity
(Lhs
), Loc
),
1333 Attribute_Name
=> Name_Constrained
),
1334 Right_Opnd
=> Cond
);
1338 Cond
:= Guard_Access
(Cond
, Loc
, N
);
1342 Make_Raise_Constraint_Error
(Loc
,
1344 Reason
=> CE_Discriminant_Check_Failed
));
1345 end Apply_Discriminant_Check
;
1347 ------------------------
1348 -- Apply_Divide_Check --
1349 ------------------------
1351 procedure Apply_Divide_Check
(N
: Node_Id
) is
1352 Loc
: constant Source_Ptr
:= Sloc
(N
);
1353 Typ
: constant Entity_Id
:= Etype
(N
);
1354 Left
: constant Node_Id
:= Left_Opnd
(N
);
1355 Right
: constant Node_Id
:= Right_Opnd
(N
);
1367 and not Backend_Divide_Checks_On_Target
1369 Determine_Range
(Right
, ROK
, Rlo
, Rhi
);
1371 -- See if division by zero possible, and if so generate test. This
1372 -- part of the test is not controlled by the -gnato switch.
1374 if Do_Division_Check
(N
) then
1375 if (not ROK
) or else (Rlo
<= 0 and then 0 <= Rhi
) then
1377 Make_Raise_Constraint_Error
(Loc
,
1380 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(Right
),
1381 Right_Opnd
=> Make_Integer_Literal
(Loc
, 0)),
1382 Reason
=> CE_Divide_By_Zero
));
1386 -- Test for extremely annoying case of xxx'First divided by -1
1388 if Do_Overflow_Check
(N
) then
1390 if Nkind
(N
) = N_Op_Divide
1391 and then Is_Signed_Integer_Type
(Typ
)
1393 Determine_Range
(Left
, LOK
, Llo
, Lhi
);
1394 LLB
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
1396 if ((not ROK
) or else (Rlo
<= (-1) and then (-1) <= Rhi
))
1398 ((not LOK
) or else (Llo
= LLB
))
1401 Make_Raise_Constraint_Error
(Loc
,
1407 Duplicate_Subexpr_Move_Checks
(Left
),
1408 Right_Opnd
=> Make_Integer_Literal
(Loc
, LLB
)),
1412 Duplicate_Subexpr
(Right
),
1414 Make_Integer_Literal
(Loc
, -1))),
1415 Reason
=> CE_Overflow_Check_Failed
));
1420 end Apply_Divide_Check
;
1422 ----------------------------------
1423 -- Apply_Float_Conversion_Check --
1424 ----------------------------------
1426 -- Let F and I be the source and target types of the conversion.
1427 -- The Ada standard specifies that a floating-point value X is rounded
1428 -- to the nearest integer, with halfway cases being rounded away from
1429 -- zero. The rounded value of X is checked against I'Range.
1431 -- The catch in the above paragraph is that there is no good way
1432 -- to know whether the round-to-integer operation resulted in
1433 -- overflow. A remedy is to perform a range check in the floating-point
1434 -- domain instead, however:
1435 -- (1) The bounds may not be known at compile time
1436 -- (2) The check must take into account possible rounding.
1437 -- (3) The range of type I may not be exactly representable in F.
1438 -- (4) The end-points I'First - 0.5 and I'Last + 0.5 may or may
1439 -- not be in range, depending on the sign of I'First and I'Last.
1440 -- (5) X may be a NaN, which will fail any comparison
1442 -- The following steps take care of these issues converting X:
1443 -- (1) If either I'First or I'Last is not known at compile time, use
1444 -- I'Base instead of I in the next three steps and perform a
1445 -- regular range check against I'Range after conversion.
1446 -- (2) If I'First - 0.5 is representable in F then let Lo be that
1447 -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be
1448 -- F'Machine (T) and let Lo_OK be (Lo >= I'First). In other words,
1449 -- take one of the closest floating-point numbers to T, and see if
1450 -- it is in range or not.
1451 -- (3) If I'Last + 0.5 is representable in F then let Hi be that value
1452 -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be
1453 -- F'Rounding (T) and let Hi_OK be (Hi <= I'Last).
1454 -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo)
1455 -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi)
1457 procedure Apply_Float_Conversion_Check
1459 Target_Typ
: Entity_Id
)
1461 LB
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1462 HB
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1463 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1464 Expr_Type
: constant Entity_Id
:= Base_Type
(Etype
(Ck_Node
));
1465 Target_Base
: constant Entity_Id
:= Implementation_Base_Type
1467 Max_Bound
: constant Uint
:= UI_Expon
1468 (Machine_Radix
(Expr_Type
),
1469 Machine_Mantissa
(Expr_Type
) - 1) - 1;
1470 -- Largest bound, so bound plus or minus half is a machine number of F
1473 Ilast
: Uint
; -- Bounds of integer type
1474 Lo
, Hi
: Ureal
; -- Bounds to check in floating-point domain
1476 Hi_OK
: Boolean; -- True iff Lo resp. Hi belongs to I'Range
1479 Hi_Chk
: Node_Id
; -- Expressions that are False iff check fails
1481 Reason
: RT_Exception_Code
;
1484 if not Compile_Time_Known_Value
(LB
)
1485 or not Compile_Time_Known_Value
(HB
)
1488 -- First check that the value falls in the range of the base
1489 -- type, to prevent overflow during conversion and then
1490 -- perform a regular range check against the (dynamic) bounds.
1492 Par
: constant Node_Id
:= Parent
(Ck_Node
);
1494 pragma Assert
(Target_Base
/= Target_Typ
);
1495 pragma Assert
(Nkind
(Par
) = N_Type_Conversion
);
1497 Temp
: constant Entity_Id
:=
1498 Make_Defining_Identifier
(Loc
,
1499 Chars
=> New_Internal_Name
('T'));
1502 Apply_Float_Conversion_Check
(Ck_Node
, Target_Base
);
1503 Set_Etype
(Temp
, Target_Base
);
1505 Insert_Action
(Parent
(Par
),
1506 Make_Object_Declaration
(Loc
,
1507 Defining_Identifier
=> Temp
,
1508 Object_Definition
=> New_Occurrence_Of
(Target_Typ
, Loc
),
1509 Expression
=> New_Copy_Tree
(Par
)),
1510 Suppress
=> All_Checks
);
1513 Make_Raise_Constraint_Error
(Loc
,
1516 Left_Opnd
=> New_Occurrence_Of
(Temp
, Loc
),
1517 Right_Opnd
=> New_Occurrence_Of
(Target_Typ
, Loc
)),
1518 Reason
=> CE_Range_Check_Failed
));
1519 Rewrite
(Par
, New_Occurrence_Of
(Temp
, Loc
));
1525 -- Get the bounds of the target type
1527 Ifirst
:= Expr_Value
(LB
);
1528 Ilast
:= Expr_Value
(HB
);
1530 -- Check against lower bound
1532 if abs (Ifirst
) < Max_Bound
then
1533 Lo
:= UR_From_Uint
(Ifirst
) - Ureal_Half
;
1534 Lo_OK
:= (Ifirst
> 0);
1536 Lo
:= Machine
(Expr_Type
, UR_From_Uint
(Ifirst
), Round_Even
, Ck_Node
);
1537 Lo_OK
:= (Lo
>= UR_From_Uint
(Ifirst
));
1542 -- Lo_Chk := (X >= Lo)
1544 Lo_Chk
:= Make_Op_Ge
(Loc
,
1545 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1546 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
1549 -- Lo_Chk := (X > Lo)
1551 Lo_Chk
:= Make_Op_Gt
(Loc
,
1552 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1553 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
1556 -- Check against higher bound
1558 if abs (Ilast
) < Max_Bound
then
1559 Hi
:= UR_From_Uint
(Ilast
) + Ureal_Half
;
1560 Hi_OK
:= (Ilast
< 0);
1562 Hi
:= Machine
(Expr_Type
, UR_From_Uint
(Ilast
), Round_Even
, Ck_Node
);
1563 Hi_OK
:= (Hi
<= UR_From_Uint
(Ilast
));
1568 -- Hi_Chk := (X <= Hi)
1570 Hi_Chk
:= Make_Op_Le
(Loc
,
1571 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1572 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
1575 -- Hi_Chk := (X < Hi)
1577 Hi_Chk
:= Make_Op_Lt
(Loc
,
1578 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1579 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
1582 -- If the bounds of the target type are the same as those of the
1583 -- base type, the check is an overflow check as a range check is
1584 -- not performed in these cases.
1586 if Expr_Value
(Type_Low_Bound
(Target_Base
)) = Ifirst
1587 and then Expr_Value
(Type_High_Bound
(Target_Base
)) = Ilast
1589 Reason
:= CE_Overflow_Check_Failed
;
1591 Reason
:= CE_Range_Check_Failed
;
1594 -- Raise CE if either conditions does not hold
1596 Insert_Action
(Ck_Node
,
1597 Make_Raise_Constraint_Error
(Loc
,
1598 Condition
=> Make_Op_Not
(Loc
, Make_Op_And
(Loc
, Lo_Chk
, Hi_Chk
)),
1600 end Apply_Float_Conversion_Check
;
1602 ------------------------
1603 -- Apply_Length_Check --
1604 ------------------------
1606 procedure Apply_Length_Check
1608 Target_Typ
: Entity_Id
;
1609 Source_Typ
: Entity_Id
:= Empty
)
1612 Apply_Selected_Length_Checks
1613 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
1614 end Apply_Length_Check
;
1616 -----------------------
1617 -- Apply_Range_Check --
1618 -----------------------
1620 procedure Apply_Range_Check
1622 Target_Typ
: Entity_Id
;
1623 Source_Typ
: Entity_Id
:= Empty
)
1626 Apply_Selected_Range_Checks
1627 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
1628 end Apply_Range_Check
;
1630 ------------------------------
1631 -- Apply_Scalar_Range_Check --
1632 ------------------------------
1634 -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check
1635 -- flag off if it is already set on.
1637 procedure Apply_Scalar_Range_Check
1639 Target_Typ
: Entity_Id
;
1640 Source_Typ
: Entity_Id
:= Empty
;
1641 Fixed_Int
: Boolean := False)
1643 Parnt
: constant Node_Id
:= Parent
(Expr
);
1645 Arr
: Node_Id
:= Empty
; -- initialize to prevent warning
1646 Arr_Typ
: Entity_Id
:= Empty
; -- initialize to prevent warning
1649 Is_Subscr_Ref
: Boolean;
1650 -- Set true if Expr is a subscript
1652 Is_Unconstrained_Subscr_Ref
: Boolean;
1653 -- Set true if Expr is a subscript of an unconstrained array. In this
1654 -- case we do not attempt to do an analysis of the value against the
1655 -- range of the subscript, since we don't know the actual subtype.
1658 -- Set to True if Expr should be regarded as a real value
1659 -- even though the type of Expr might be discrete.
1661 procedure Bad_Value
;
1662 -- Procedure called if value is determined to be out of range
1668 procedure Bad_Value
is
1670 Apply_Compile_Time_Constraint_Error
1671 (Expr
, "value not in range of}?", CE_Range_Check_Failed
,
1676 -- Start of processing for Apply_Scalar_Range_Check
1679 if Inside_A_Generic
then
1682 -- Return if check obviously not needed. Note that we do not check
1683 -- for the expander being inactive, since this routine does not
1684 -- insert any code, but it does generate useful warnings sometimes,
1685 -- which we would like even if we are in semantics only mode.
1687 elsif Target_Typ
= Any_Type
1688 or else not Is_Scalar_Type
(Target_Typ
)
1689 or else Raises_Constraint_Error
(Expr
)
1694 -- Now, see if checks are suppressed
1697 Is_List_Member
(Expr
) and then Nkind
(Parnt
) = N_Indexed_Component
;
1699 if Is_Subscr_Ref
then
1700 Arr
:= Prefix
(Parnt
);
1701 Arr_Typ
:= Get_Actual_Subtype_If_Available
(Arr
);
1704 if not Do_Range_Check
(Expr
) then
1706 -- Subscript reference. Check for Index_Checks suppressed
1708 if Is_Subscr_Ref
then
1710 -- Check array type and its base type
1712 if Index_Checks_Suppressed
(Arr_Typ
)
1713 or else Index_Checks_Suppressed
(Base_Type
(Arr_Typ
))
1717 -- Check array itself if it is an entity name
1719 elsif Is_Entity_Name
(Arr
)
1720 and then Index_Checks_Suppressed
(Entity
(Arr
))
1724 -- Check expression itself if it is an entity name
1726 elsif Is_Entity_Name
(Expr
)
1727 and then Index_Checks_Suppressed
(Entity
(Expr
))
1732 -- All other cases, check for Range_Checks suppressed
1735 -- Check target type and its base type
1737 if Range_Checks_Suppressed
(Target_Typ
)
1738 or else Range_Checks_Suppressed
(Base_Type
(Target_Typ
))
1742 -- Check expression itself if it is an entity name
1744 elsif Is_Entity_Name
(Expr
)
1745 and then Range_Checks_Suppressed
(Entity
(Expr
))
1749 -- If Expr is part of an assignment statement, then check
1750 -- left side of assignment if it is an entity name.
1752 elsif Nkind
(Parnt
) = N_Assignment_Statement
1753 and then Is_Entity_Name
(Name
(Parnt
))
1754 and then Range_Checks_Suppressed
(Entity
(Name
(Parnt
)))
1761 -- Do not set range checks if they are killed
1763 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
1764 and then Kill_Range_Check
(Expr
)
1769 -- Do not set range checks for any values from System.Scalar_Values
1770 -- since the whole idea of such values is to avoid checking them!
1772 if Is_Entity_Name
(Expr
)
1773 and then Is_RTU
(Scope
(Entity
(Expr
)), System_Scalar_Values
)
1778 -- Now see if we need a check
1780 if No
(Source_Typ
) then
1781 S_Typ
:= Etype
(Expr
);
1783 S_Typ
:= Source_Typ
;
1786 if not Is_Scalar_Type
(S_Typ
) or else S_Typ
= Any_Type
then
1790 Is_Unconstrained_Subscr_Ref
:=
1791 Is_Subscr_Ref
and then not Is_Constrained
(Arr_Typ
);
1793 -- Always do a range check if the source type includes infinities
1794 -- and the target type does not include infinities. We do not do
1795 -- this if range checks are killed.
1797 if Is_Floating_Point_Type
(S_Typ
)
1798 and then Has_Infinities
(S_Typ
)
1799 and then not Has_Infinities
(Target_Typ
)
1801 Enable_Range_Check
(Expr
);
1804 -- Return if we know expression is definitely in the range of
1805 -- the target type as determined by Determine_Range. Right now
1806 -- we only do this for discrete types, and not fixed-point or
1807 -- floating-point types.
1809 -- The additional less-precise tests below catch these cases.
1811 -- Note: skip this if we are given a source_typ, since the point
1812 -- of supplying a Source_Typ is to stop us looking at the expression.
1813 -- could sharpen this test to be out parameters only ???
1815 if Is_Discrete_Type
(Target_Typ
)
1816 and then Is_Discrete_Type
(Etype
(Expr
))
1817 and then not Is_Unconstrained_Subscr_Ref
1818 and then No
(Source_Typ
)
1821 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1822 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1827 if Compile_Time_Known_Value
(Tlo
)
1828 and then Compile_Time_Known_Value
(Thi
)
1831 Lov
: constant Uint
:= Expr_Value
(Tlo
);
1832 Hiv
: constant Uint
:= Expr_Value
(Thi
);
1835 -- If range is null, we for sure have a constraint error
1836 -- (we don't even need to look at the value involved,
1837 -- since all possible values will raise CE).
1844 -- Otherwise determine range of value
1846 Determine_Range
(Expr
, OK
, Lo
, Hi
);
1850 -- If definitely in range, all OK
1852 if Lo
>= Lov
and then Hi
<= Hiv
then
1855 -- If definitely not in range, warn
1857 elsif Lov
> Hi
or else Hiv
< Lo
then
1861 -- Otherwise we don't know
1873 Is_Floating_Point_Type
(S_Typ
)
1874 or else (Is_Fixed_Point_Type
(S_Typ
) and then not Fixed_Int
);
1876 -- Check if we can determine at compile time whether Expr is in the
1877 -- range of the target type. Note that if S_Typ is within the bounds
1878 -- of Target_Typ then this must be the case. This check is meaningful
1879 -- only if this is not a conversion between integer and real types.
1881 if not Is_Unconstrained_Subscr_Ref
1883 Is_Discrete_Type
(S_Typ
) = Is_Discrete_Type
(Target_Typ
)
1885 (In_Subrange_Of
(S_Typ
, Target_Typ
, Fixed_Int
)
1887 Is_In_Range
(Expr
, Target_Typ
, Fixed_Int
, Int_Real
))
1891 elsif Is_Out_Of_Range
(Expr
, Target_Typ
, Fixed_Int
, Int_Real
) then
1895 -- In the floating-point case, we only do range checks if the
1896 -- type is constrained. We definitely do NOT want range checks
1897 -- for unconstrained types, since we want to have infinities
1899 elsif Is_Floating_Point_Type
(S_Typ
) then
1900 if Is_Constrained
(S_Typ
) then
1901 Enable_Range_Check
(Expr
);
1904 -- For all other cases we enable a range check unconditionally
1907 Enable_Range_Check
(Expr
);
1910 end Apply_Scalar_Range_Check
;
1912 ----------------------------------
1913 -- Apply_Selected_Length_Checks --
1914 ----------------------------------
1916 procedure Apply_Selected_Length_Checks
1918 Target_Typ
: Entity_Id
;
1919 Source_Typ
: Entity_Id
;
1920 Do_Static
: Boolean)
1923 R_Result
: Check_Result
;
1926 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1927 Checks_On
: constant Boolean :=
1928 (not Index_Checks_Suppressed
(Target_Typ
))
1930 (not Length_Checks_Suppressed
(Target_Typ
));
1933 if not Expander_Active
then
1938 Selected_Length_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
1940 for J
in 1 .. 2 loop
1941 R_Cno
:= R_Result
(J
);
1942 exit when No
(R_Cno
);
1944 -- A length check may mention an Itype which is attached to a
1945 -- subsequent node. At the top level in a package this can cause
1946 -- an order-of-elaboration problem, so we make sure that the itype
1947 -- is referenced now.
1949 if Ekind
(Current_Scope
) = E_Package
1950 and then Is_Compilation_Unit
(Current_Scope
)
1952 Ensure_Defined
(Target_Typ
, Ck_Node
);
1954 if Present
(Source_Typ
) then
1955 Ensure_Defined
(Source_Typ
, Ck_Node
);
1957 elsif Is_Itype
(Etype
(Ck_Node
)) then
1958 Ensure_Defined
(Etype
(Ck_Node
), Ck_Node
);
1962 -- If the item is a conditional raise of constraint error,
1963 -- then have a look at what check is being performed and
1966 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
1967 and then Present
(Condition
(R_Cno
))
1969 Cond
:= Condition
(R_Cno
);
1971 if not Has_Dynamic_Length_Check
(Ck_Node
)
1974 Insert_Action
(Ck_Node
, R_Cno
);
1976 if not Do_Static
then
1977 Set_Has_Dynamic_Length_Check
(Ck_Node
);
1981 -- Output a warning if the condition is known to be True
1983 if Is_Entity_Name
(Cond
)
1984 and then Entity
(Cond
) = Standard_True
1986 Apply_Compile_Time_Constraint_Error
1987 (Ck_Node
, "wrong length for array of}?",
1988 CE_Length_Check_Failed
,
1992 -- If we were only doing a static check, or if checks are not
1993 -- on, then we want to delete the check, since it is not needed.
1994 -- We do this by replacing the if statement by a null statement
1996 elsif Do_Static
or else not Checks_On
then
1997 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
2001 Install_Static_Check
(R_Cno
, Loc
);
2006 end Apply_Selected_Length_Checks
;
2008 ---------------------------------
2009 -- Apply_Selected_Range_Checks --
2010 ---------------------------------
2012 procedure Apply_Selected_Range_Checks
2014 Target_Typ
: Entity_Id
;
2015 Source_Typ
: Entity_Id
;
2016 Do_Static
: Boolean)
2019 R_Result
: Check_Result
;
2022 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
2023 Checks_On
: constant Boolean :=
2024 (not Index_Checks_Suppressed
(Target_Typ
))
2026 (not Range_Checks_Suppressed
(Target_Typ
));
2029 if not Expander_Active
or else not Checks_On
then
2034 Selected_Range_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
2036 for J
in 1 .. 2 loop
2038 R_Cno
:= R_Result
(J
);
2039 exit when No
(R_Cno
);
2041 -- If the item is a conditional raise of constraint error,
2042 -- then have a look at what check is being performed and
2045 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
2046 and then Present
(Condition
(R_Cno
))
2048 Cond
:= Condition
(R_Cno
);
2050 if not Has_Dynamic_Range_Check
(Ck_Node
) then
2051 Insert_Action
(Ck_Node
, R_Cno
);
2053 if not Do_Static
then
2054 Set_Has_Dynamic_Range_Check
(Ck_Node
);
2058 -- Output a warning if the condition is known to be True
2060 if Is_Entity_Name
(Cond
)
2061 and then Entity
(Cond
) = Standard_True
2063 -- Since an N_Range is technically not an expression, we
2064 -- have to set one of the bounds to C_E and then just flag
2065 -- the N_Range. The warning message will point to the
2066 -- lower bound and complain about a range, which seems OK.
2068 if Nkind
(Ck_Node
) = N_Range
then
2069 Apply_Compile_Time_Constraint_Error
2070 (Low_Bound
(Ck_Node
), "static range out of bounds of}?",
2071 CE_Range_Check_Failed
,
2075 Set_Raises_Constraint_Error
(Ck_Node
);
2078 Apply_Compile_Time_Constraint_Error
2079 (Ck_Node
, "static value out of range of}?",
2080 CE_Range_Check_Failed
,
2085 -- If we were only doing a static check, or if checks are not
2086 -- on, then we want to delete the check, since it is not needed.
2087 -- We do this by replacing the if statement by a null statement
2089 elsif Do_Static
or else not Checks_On
then
2090 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
2094 Install_Static_Check
(R_Cno
, Loc
);
2097 end Apply_Selected_Range_Checks
;
2099 -------------------------------
2100 -- Apply_Static_Length_Check --
2101 -------------------------------
2103 procedure Apply_Static_Length_Check
2105 Target_Typ
: Entity_Id
;
2106 Source_Typ
: Entity_Id
:= Empty
)
2109 Apply_Selected_Length_Checks
2110 (Expr
, Target_Typ
, Source_Typ
, Do_Static
=> True);
2111 end Apply_Static_Length_Check
;
2113 -------------------------------------
2114 -- Apply_Subscript_Validity_Checks --
2115 -------------------------------------
2117 procedure Apply_Subscript_Validity_Checks
(Expr
: Node_Id
) is
2121 pragma Assert
(Nkind
(Expr
) = N_Indexed_Component
);
2123 -- Loop through subscripts
2125 Sub
:= First
(Expressions
(Expr
));
2126 while Present
(Sub
) loop
2128 -- Check one subscript. Note that we do not worry about
2129 -- enumeration type with holes, since we will convert the
2130 -- value to a Pos value for the subscript, and that convert
2131 -- will do the necessary validity check.
2133 Ensure_Valid
(Sub
, Holes_OK
=> True);
2135 -- Move to next subscript
2139 end Apply_Subscript_Validity_Checks
;
2141 ----------------------------------
2142 -- Apply_Type_Conversion_Checks --
2143 ----------------------------------
2145 procedure Apply_Type_Conversion_Checks
(N
: Node_Id
) is
2146 Target_Type
: constant Entity_Id
:= Etype
(N
);
2147 Target_Base
: constant Entity_Id
:= Base_Type
(Target_Type
);
2148 Expr
: constant Node_Id
:= Expression
(N
);
2149 Expr_Type
: constant Entity_Id
:= Etype
(Expr
);
2152 if Inside_A_Generic
then
2155 -- Skip these checks if serious errors detected, there are some nasty
2156 -- situations of incomplete trees that blow things up.
2158 elsif Serious_Errors_Detected
> 0 then
2161 -- Scalar type conversions of the form Target_Type (Expr) require
2162 -- a range check if we cannot be sure that Expr is in the base type
2163 -- of Target_Typ and also that Expr is in the range of Target_Typ.
2164 -- These are not quite the same condition from an implementation
2165 -- point of view, but clearly the second includes the first.
2167 elsif Is_Scalar_Type
(Target_Type
) then
2169 Conv_OK
: constant Boolean := Conversion_OK
(N
);
2170 -- If the Conversion_OK flag on the type conversion is set
2171 -- and no floating point type is involved in the type conversion
2172 -- then fixed point values must be read as integral values.
2174 Float_To_Int
: constant Boolean :=
2175 Is_Floating_Point_Type
(Expr_Type
)
2176 and then Is_Integer_Type
(Target_Type
);
2179 if not Overflow_Checks_Suppressed
(Target_Base
)
2180 and then not In_Subrange_Of
(Expr_Type
, Target_Base
, Conv_OK
)
2181 and then not Float_To_Int
2183 Set_Do_Overflow_Check
(N
);
2186 if not Range_Checks_Suppressed
(Target_Type
)
2187 and then not Range_Checks_Suppressed
(Expr_Type
)
2189 if Float_To_Int
then
2190 Apply_Float_Conversion_Check
(Expr
, Target_Type
);
2192 Apply_Scalar_Range_Check
2193 (Expr
, Target_Type
, Fixed_Int
=> Conv_OK
);
2198 elsif Comes_From_Source
(N
)
2199 and then Is_Record_Type
(Target_Type
)
2200 and then Is_Derived_Type
(Target_Type
)
2201 and then not Is_Tagged_Type
(Target_Type
)
2202 and then not Is_Constrained
(Target_Type
)
2203 and then Present
(Stored_Constraint
(Target_Type
))
2205 -- An unconstrained derived type may have inherited discriminant
2206 -- Build an actual discriminant constraint list using the stored
2207 -- constraint, to verify that the expression of the parent type
2208 -- satisfies the constraints imposed by the (unconstrained!)
2209 -- derived type. This applies to value conversions, not to view
2210 -- conversions of tagged types.
2213 Loc
: constant Source_Ptr
:= Sloc
(N
);
2215 Constraint
: Elmt_Id
;
2216 Discr_Value
: Node_Id
;
2219 New_Constraints
: constant Elist_Id
:= New_Elmt_List
;
2220 Old_Constraints
: constant Elist_Id
:=
2221 Discriminant_Constraint
(Expr_Type
);
2224 Constraint
:= First_Elmt
(Stored_Constraint
(Target_Type
));
2226 while Present
(Constraint
) loop
2227 Discr_Value
:= Node
(Constraint
);
2229 if Is_Entity_Name
(Discr_Value
)
2230 and then Ekind
(Entity
(Discr_Value
)) = E_Discriminant
2232 Discr
:= Corresponding_Discriminant
(Entity
(Discr_Value
));
2235 and then Scope
(Discr
) = Base_Type
(Expr_Type
)
2237 -- Parent is constrained by new discriminant. Obtain
2238 -- Value of original discriminant in expression. If
2239 -- the new discriminant has been used to constrain more
2240 -- than one of the stored discriminants, this will
2241 -- provide the required consistency check.
2244 Make_Selected_Component
(Loc
,
2246 Duplicate_Subexpr_No_Checks
2247 (Expr
, Name_Req
=> True),
2249 Make_Identifier
(Loc
, Chars
(Discr
))),
2253 -- Discriminant of more remote ancestor ???
2258 -- Derived type definition has an explicit value for
2259 -- this stored discriminant.
2263 (Duplicate_Subexpr_No_Checks
(Discr_Value
),
2267 Next_Elmt
(Constraint
);
2270 -- Use the unconstrained expression type to retrieve the
2271 -- discriminants of the parent, and apply momentarily the
2272 -- discriminant constraint synthesized above.
2274 Set_Discriminant_Constraint
(Expr_Type
, New_Constraints
);
2275 Cond
:= Build_Discriminant_Checks
(Expr
, Expr_Type
);
2276 Set_Discriminant_Constraint
(Expr_Type
, Old_Constraints
);
2279 Make_Raise_Constraint_Error
(Loc
,
2281 Reason
=> CE_Discriminant_Check_Failed
));
2284 -- For arrays, conversions are applied during expansion, to take
2285 -- into accounts changes of representation. The checks become range
2286 -- checks on the base type or length checks on the subtype, depending
2287 -- on whether the target type is unconstrained or constrained.
2292 end Apply_Type_Conversion_Checks
;
2294 ----------------------------------------------
2295 -- Apply_Universal_Integer_Attribute_Checks --
2296 ----------------------------------------------
2298 procedure Apply_Universal_Integer_Attribute_Checks
(N
: Node_Id
) is
2299 Loc
: constant Source_Ptr
:= Sloc
(N
);
2300 Typ
: constant Entity_Id
:= Etype
(N
);
2303 if Inside_A_Generic
then
2306 -- Nothing to do if checks are suppressed
2308 elsif Range_Checks_Suppressed
(Typ
)
2309 and then Overflow_Checks_Suppressed
(Typ
)
2313 -- Nothing to do if the attribute does not come from source. The
2314 -- internal attributes we generate of this type do not need checks,
2315 -- and furthermore the attempt to check them causes some circular
2316 -- elaboration orders when dealing with packed types.
2318 elsif not Comes_From_Source
(N
) then
2321 -- If the prefix is a selected component that depends on a discriminant
2322 -- the check may improperly expose a discriminant instead of using
2323 -- the bounds of the object itself. Set the type of the attribute to
2324 -- the base type of the context, so that a check will be imposed when
2325 -- needed (e.g. if the node appears as an index).
2327 elsif Nkind
(Prefix
(N
)) = N_Selected_Component
2328 and then Ekind
(Typ
) = E_Signed_Integer_Subtype
2329 and then Depends_On_Discriminant
(Scalar_Range
(Typ
))
2331 Set_Etype
(N
, Base_Type
(Typ
));
2333 -- Otherwise, replace the attribute node with a type conversion
2334 -- node whose expression is the attribute, retyped to universal
2335 -- integer, and whose subtype mark is the target type. The call
2336 -- to analyze this conversion will set range and overflow checks
2337 -- as required for proper detection of an out of range value.
2340 Set_Etype
(N
, Universal_Integer
);
2341 Set_Analyzed
(N
, True);
2344 Make_Type_Conversion
(Loc
,
2345 Subtype_Mark
=> New_Occurrence_Of
(Typ
, Loc
),
2346 Expression
=> Relocate_Node
(N
)));
2348 Analyze_And_Resolve
(N
, Typ
);
2352 end Apply_Universal_Integer_Attribute_Checks
;
2354 -------------------------------
2355 -- Build_Discriminant_Checks --
2356 -------------------------------
2358 function Build_Discriminant_Checks
2360 T_Typ
: Entity_Id
) return Node_Id
2362 Loc
: constant Source_Ptr
:= Sloc
(N
);
2365 Disc_Ent
: Entity_Id
;
2371 Disc
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
2373 -- For a fully private type, use the discriminants of the parent type
2375 if Is_Private_Type
(T_Typ
)
2376 and then No
(Full_View
(T_Typ
))
2378 Disc_Ent
:= First_Discriminant
(Etype
(Base_Type
(T_Typ
)));
2380 Disc_Ent
:= First_Discriminant
(T_Typ
);
2383 while Present
(Disc
) loop
2384 Dval
:= Node
(Disc
);
2386 if Nkind
(Dval
) = N_Identifier
2387 and then Ekind
(Entity
(Dval
)) = E_Discriminant
2389 Dval
:= New_Occurrence_Of
(Discriminal
(Entity
(Dval
)), Loc
);
2391 Dval
:= Duplicate_Subexpr_No_Checks
(Dval
);
2394 -- If we have an Unchecked_Union node, we can infer the discriminants
2397 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
2399 Get_Discriminant_Value
(
2400 First_Discriminant
(T_Typ
),
2402 Stored_Constraint
(T_Typ
)));
2406 Make_Selected_Component
(Loc
,
2408 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
2410 Make_Identifier
(Loc
, Chars
(Disc_Ent
)));
2412 Set_Is_In_Discriminant_Check
(Dref
);
2415 Evolve_Or_Else
(Cond
,
2418 Right_Opnd
=> Dval
));
2421 Next_Discriminant
(Disc_Ent
);
2425 end Build_Discriminant_Checks
;
2427 -----------------------------------
2428 -- Check_Valid_Lvalue_Subscripts --
2429 -----------------------------------
2431 procedure Check_Valid_Lvalue_Subscripts
(Expr
: Node_Id
) is
2433 -- Skip this if range checks are suppressed
2435 if Range_Checks_Suppressed
(Etype
(Expr
)) then
2438 -- Only do this check for expressions that come from source. We
2439 -- assume that expander generated assignments explicitly include
2440 -- any necessary checks. Note that this is not just an optimization,
2441 -- it avoids infinite recursions!
2443 elsif not Comes_From_Source
(Expr
) then
2446 -- For a selected component, check the prefix
2448 elsif Nkind
(Expr
) = N_Selected_Component
then
2449 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
2452 -- Case of indexed component
2454 elsif Nkind
(Expr
) = N_Indexed_Component
then
2455 Apply_Subscript_Validity_Checks
(Expr
);
2457 -- Prefix may itself be or contain an indexed component, and
2458 -- these subscripts need checking as well
2460 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
2462 end Check_Valid_Lvalue_Subscripts
;
2464 ----------------------------------
2465 -- Null_Exclusion_Static_Checks --
2466 ----------------------------------
2468 procedure Null_Exclusion_Static_Checks
(N
: Node_Id
) is
2469 K
: constant Node_Kind
:= Nkind
(N
);
2471 Related_Nod
: Node_Id
;
2472 Has_Null_Exclusion
: Boolean := False;
2474 type Msg_Kind
is (Components
, Formals
, Objects
);
2475 Msg_K
: Msg_Kind
:= Objects
;
2476 -- Used by local subprograms to generate precise error messages
2478 procedure Check_Must_Be_Access
2480 Has_Null_Exclusion
: Boolean);
2481 -- ??? local subprograms must have comment on spec
2483 procedure Check_Already_Null_Excluding_Type
2485 Has_Null_Exclusion
: Boolean;
2486 Related_Nod
: Node_Id
);
2487 -- ??? local subprograms must have comment on spec
2489 procedure Check_Must_Be_Initialized
2491 Related_Nod
: Node_Id
);
2492 -- ??? local subprograms must have comment on spec
2494 procedure Check_Null_Not_Allowed
(N
: Node_Id
);
2495 -- ??? local subprograms must have comment on spec
2497 -- ??? following bodies lack comments
2499 --------------------------
2500 -- Check_Must_Be_Access --
2501 --------------------------
2503 procedure Check_Must_Be_Access
2505 Has_Null_Exclusion
: Boolean)
2508 if Has_Null_Exclusion
2509 and then not Is_Access_Type
(Typ
)
2511 Error_Msg_N
("(Ada 2005) must be an access type", Related_Nod
);
2513 end Check_Must_Be_Access
;
2515 ---------------------------------------
2516 -- Check_Already_Null_Excluding_Type --
2517 ---------------------------------------
2519 procedure Check_Already_Null_Excluding_Type
2521 Has_Null_Exclusion
: Boolean;
2522 Related_Nod
: Node_Id
)
2525 if Has_Null_Exclusion
2526 and then Can_Never_Be_Null
(Typ
)
2529 ("(Ada 2005) already a null-excluding type", Related_Nod
);
2531 end Check_Already_Null_Excluding_Type
;
2533 -------------------------------
2534 -- Check_Must_Be_Initialized --
2535 -------------------------------
2537 procedure Check_Must_Be_Initialized
2539 Related_Nod
: Node_Id
)
2541 Expr
: constant Node_Id
:= Expression
(N
);
2544 pragma Assert
(Nkind
(N
) = N_Component_Declaration
2545 or else Nkind
(N
) = N_Object_Declaration
);
2547 if not Present
(Expr
) then
2551 ("(Ada 2005) null-excluding components must be " &
2552 "initialized", Related_Nod
);
2556 ("(Ada 2005) null-excluding formals must be initialized",
2561 ("(Ada 2005) null-excluding objects must be initialized",
2565 end Check_Must_Be_Initialized
;
2567 ----------------------------
2568 -- Check_Null_Not_Allowed --
2569 ----------------------------
2571 procedure Check_Null_Not_Allowed
(N
: Node_Id
) is
2572 Expr
: constant Node_Id
:= Expression
(N
);
2576 and then Nkind
(Expr
) = N_Null
2581 ("(Ada 2005) NULL not allowed in null-excluding " &
2582 "components", Expr
);
2586 ("(Ada 2005) NULL not allowed in null-excluding formals",
2591 ("(Ada 2005) NULL not allowed in null-excluding objects",
2595 end Check_Null_Not_Allowed
;
2597 -- Start of processing for Null_Exclusion_Static_Checks
2600 pragma Assert
(K
= N_Component_Declaration
2601 or else K
= N_Parameter_Specification
2602 or else K
= N_Object_Declaration
2603 or else K
= N_Discriminant_Specification
2604 or else K
= N_Allocator
);
2607 when N_Component_Declaration
=>
2608 Msg_K
:= Components
;
2610 if not Present
(Access_Definition
(Component_Definition
(N
))) then
2611 Has_Null_Exclusion
:= Null_Exclusion_Present
2612 (Component_Definition
(N
));
2613 Typ
:= Etype
(Subtype_Indication
(Component_Definition
(N
)));
2614 Related_Nod
:= Subtype_Indication
(Component_Definition
(N
));
2615 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2616 Check_Already_Null_Excluding_Type
2617 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2618 Check_Must_Be_Initialized
(N
, Related_Nod
);
2621 Check_Null_Not_Allowed
(N
);
2623 when N_Parameter_Specification
=>
2625 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2626 Typ
:= Entity
(Parameter_Type
(N
));
2627 Related_Nod
:= Parameter_Type
(N
);
2628 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2629 Check_Already_Null_Excluding_Type
2630 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2631 Check_Null_Not_Allowed
(N
);
2633 when N_Object_Declaration
=>
2635 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2636 Typ
:= Entity
(Object_Definition
(N
));
2637 Related_Nod
:= Object_Definition
(N
);
2638 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2639 Check_Already_Null_Excluding_Type
2640 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2641 Check_Must_Be_Initialized
(N
, Related_Nod
);
2642 Check_Null_Not_Allowed
(N
);
2644 when N_Discriminant_Specification
=>
2645 Msg_K
:= Components
;
2647 if Nkind
(Discriminant_Type
(N
)) /= N_Access_Definition
then
2648 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2649 Typ
:= Etype
(Defining_Identifier
(N
));
2650 Related_Nod
:= Discriminant_Type
(N
);
2651 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2652 Check_Already_Null_Excluding_Type
2653 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2656 Check_Null_Not_Allowed
(N
);
2660 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2661 Typ
:= Etype
(Expression
(N
));
2663 if Nkind
(Expression
(N
)) = N_Qualified_Expression
then
2664 Related_Nod
:= Subtype_Mark
(Expression
(N
));
2666 Related_Nod
:= Expression
(N
);
2669 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2670 Check_Already_Null_Excluding_Type
2671 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2672 Check_Null_Not_Allowed
(N
);
2675 raise Program_Error
;
2677 end Null_Exclusion_Static_Checks
;
2679 ----------------------------------
2680 -- Conditional_Statements_Begin --
2681 ----------------------------------
2683 procedure Conditional_Statements_Begin
is
2685 Saved_Checks_TOS
:= Saved_Checks_TOS
+ 1;
2687 -- If stack overflows, kill all checks, that way we know to
2688 -- simply reset the number of saved checks to zero on return.
2689 -- This should never occur in practice.
2691 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
2694 -- In the normal case, we just make a new stack entry saving
2695 -- the current number of saved checks for a later restore.
2698 Saved_Checks_Stack
(Saved_Checks_TOS
) := Num_Saved_Checks
;
2700 if Debug_Flag_CC
then
2701 w
("Conditional_Statements_Begin: Num_Saved_Checks = ",
2705 end Conditional_Statements_Begin
;
2707 --------------------------------
2708 -- Conditional_Statements_End --
2709 --------------------------------
2711 procedure Conditional_Statements_End
is
2713 pragma Assert
(Saved_Checks_TOS
> 0);
2715 -- If the saved checks stack overflowed, then we killed all
2716 -- checks, so setting the number of saved checks back to
2717 -- zero is correct. This should never occur in practice.
2719 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
2720 Num_Saved_Checks
:= 0;
2722 -- In the normal case, restore the number of saved checks
2723 -- from the top stack entry.
2726 Num_Saved_Checks
:= Saved_Checks_Stack
(Saved_Checks_TOS
);
2727 if Debug_Flag_CC
then
2728 w
("Conditional_Statements_End: Num_Saved_Checks = ",
2733 Saved_Checks_TOS
:= Saved_Checks_TOS
- 1;
2734 end Conditional_Statements_End
;
2736 ---------------------
2737 -- Determine_Range --
2738 ---------------------
2740 Cache_Size
: constant := 2 ** 10;
2741 type Cache_Index
is range 0 .. Cache_Size
- 1;
2742 -- Determine size of below cache (power of 2 is more efficient!)
2744 Determine_Range_Cache_N
: array (Cache_Index
) of Node_Id
;
2745 Determine_Range_Cache_Lo
: array (Cache_Index
) of Uint
;
2746 Determine_Range_Cache_Hi
: array (Cache_Index
) of Uint
;
2747 -- The above arrays are used to implement a small direct cache
2748 -- for Determine_Range calls. Because of the way Determine_Range
2749 -- recursively traces subexpressions, and because overflow checking
2750 -- calls the routine on the way up the tree, a quadratic behavior
2751 -- can otherwise be encountered in large expressions. The cache
2752 -- entry for node N is stored in the (N mod Cache_Size) entry, and
2753 -- can be validated by checking the actual node value stored there.
2755 procedure Determine_Range
2761 Typ
: constant Entity_Id
:= Etype
(N
);
2765 -- Lo and Hi bounds of left operand
2769 -- Lo and Hi bounds of right (or only) operand
2772 -- Temp variable used to hold a bound node
2775 -- High bound of base type of expression
2779 -- Refined values for low and high bounds, after tightening
2782 -- Used in lower level calls to indicate if call succeeded
2784 Cindex
: Cache_Index
;
2785 -- Used to search cache
2787 function OK_Operands
return Boolean;
2788 -- Used for binary operators. Determines the ranges of the left and
2789 -- right operands, and if they are both OK, returns True, and puts
2790 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left
2796 function OK_Operands
return Boolean is
2798 Determine_Range
(Left_Opnd
(N
), OK1
, Lo_Left
, Hi_Left
);
2804 Determine_Range
(Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
);
2808 -- Start of processing for Determine_Range
2811 -- Prevent junk warnings by initializing range variables
2818 -- If the type is not discrete, or is undefined, then we can't
2819 -- do anything about determining the range.
2821 if No
(Typ
) or else not Is_Discrete_Type
(Typ
)
2822 or else Error_Posted
(N
)
2828 -- For all other cases, we can determine the range
2832 -- If value is compile time known, then the possible range is the
2833 -- one value that we know this expression definitely has!
2835 if Compile_Time_Known_Value
(N
) then
2836 Lo
:= Expr_Value
(N
);
2841 -- Return if already in the cache
2843 Cindex
:= Cache_Index
(N
mod Cache_Size
);
2845 if Determine_Range_Cache_N
(Cindex
) = N
then
2846 Lo
:= Determine_Range_Cache_Lo
(Cindex
);
2847 Hi
:= Determine_Range_Cache_Hi
(Cindex
);
2851 -- Otherwise, start by finding the bounds of the type of the
2852 -- expression, the value cannot be outside this range (if it
2853 -- is, then we have an overflow situation, which is a separate
2854 -- check, we are talking here only about the expression value).
2856 -- We use the actual bound unless it is dynamic, in which case
2857 -- use the corresponding base type bound if possible. If we can't
2858 -- get a bound then we figure we can't determine the range (a
2859 -- peculiar case, that perhaps cannot happen, but there is no
2860 -- point in bombing in this optimization circuit.
2862 -- First the low bound
2864 Bound
:= Type_Low_Bound
(Typ
);
2866 if Compile_Time_Known_Value
(Bound
) then
2867 Lo
:= Expr_Value
(Bound
);
2869 elsif Compile_Time_Known_Value
(Type_Low_Bound
(Base_Type
(Typ
))) then
2870 Lo
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
2877 -- Now the high bound
2879 Bound
:= Type_High_Bound
(Typ
);
2881 -- We need the high bound of the base type later on, and this should
2882 -- always be compile time known. Again, it is not clear that this
2883 -- can ever be false, but no point in bombing.
2885 if Compile_Time_Known_Value
(Type_High_Bound
(Base_Type
(Typ
))) then
2886 Hbound
:= Expr_Value
(Type_High_Bound
(Base_Type
(Typ
)));
2894 -- If we have a static subtype, then that may have a tighter bound
2895 -- so use the upper bound of the subtype instead in this case.
2897 if Compile_Time_Known_Value
(Bound
) then
2898 Hi
:= Expr_Value
(Bound
);
2901 -- We may be able to refine this value in certain situations. If
2902 -- refinement is possible, then Lor and Hir are set to possibly
2903 -- tighter bounds, and OK1 is set to True.
2907 -- For unary plus, result is limited by range of operand
2910 Determine_Range
(Right_Opnd
(N
), OK1
, Lor
, Hir
);
2912 -- For unary minus, determine range of operand, and negate it
2915 Determine_Range
(Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
);
2922 -- For binary addition, get range of each operand and do the
2923 -- addition to get the result range.
2927 Lor
:= Lo_Left
+ Lo_Right
;
2928 Hir
:= Hi_Left
+ Hi_Right
;
2931 -- Division is tricky. The only case we consider is where the
2932 -- right operand is a positive constant, and in this case we
2933 -- simply divide the bounds of the left operand
2937 if Lo_Right
= Hi_Right
2938 and then Lo_Right
> 0
2940 Lor
:= Lo_Left
/ Lo_Right
;
2941 Hir
:= Hi_Left
/ Lo_Right
;
2948 -- For binary subtraction, get range of each operand and do
2949 -- the worst case subtraction to get the result range.
2951 when N_Op_Subtract
=>
2953 Lor
:= Lo_Left
- Hi_Right
;
2954 Hir
:= Hi_Left
- Lo_Right
;
2957 -- For MOD, if right operand is a positive constant, then
2958 -- result must be in the allowable range of mod results.
2962 if Lo_Right
= Hi_Right
2963 and then Lo_Right
/= 0
2965 if Lo_Right
> 0 then
2967 Hir
:= Lo_Right
- 1;
2969 else -- Lo_Right < 0
2970 Lor
:= Lo_Right
+ 1;
2979 -- For REM, if right operand is a positive constant, then
2980 -- result must be in the allowable range of mod results.
2984 if Lo_Right
= Hi_Right
2985 and then Lo_Right
/= 0
2988 Dval
: constant Uint
:= (abs Lo_Right
) - 1;
2991 -- The sign of the result depends on the sign of the
2992 -- dividend (but not on the sign of the divisor, hence
2993 -- the abs operation above).
3013 -- Attribute reference cases
3015 when N_Attribute_Reference
=>
3016 case Attribute_Name
(N
) is
3018 -- For Pos/Val attributes, we can refine the range using the
3019 -- possible range of values of the attribute expression
3021 when Name_Pos | Name_Val
=>
3022 Determine_Range
(First
(Expressions
(N
)), OK1
, Lor
, Hir
);
3024 -- For Length attribute, use the bounds of the corresponding
3025 -- index type to refine the range.
3029 Atyp
: Entity_Id
:= Etype
(Prefix
(N
));
3037 if Is_Access_Type
(Atyp
) then
3038 Atyp
:= Designated_Type
(Atyp
);
3041 -- For string literal, we know exact value
3043 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
3045 Lo
:= String_Literal_Length
(Atyp
);
3046 Hi
:= String_Literal_Length
(Atyp
);
3050 -- Otherwise check for expression given
3052 if No
(Expressions
(N
)) then
3056 UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
3059 Indx
:= First_Index
(Atyp
);
3060 for J
in 2 .. Inum
loop
3061 Indx
:= Next_Index
(Indx
);
3065 (Type_Low_Bound
(Etype
(Indx
)), OK1
, LL
, LU
);
3069 (Type_High_Bound
(Etype
(Indx
)), OK1
, UL
, UU
);
3073 -- The maximum value for Length is the biggest
3074 -- possible gap between the values of the bounds.
3075 -- But of course, this value cannot be negative.
3077 Hir
:= UI_Max
(Uint_0
, UU
- LL
);
3079 -- For constrained arrays, the minimum value for
3080 -- Length is taken from the actual value of the
3081 -- bounds, since the index will be exactly of
3084 if Is_Constrained
(Atyp
) then
3085 Lor
:= UI_Max
(Uint_0
, UL
- LU
);
3087 -- For an unconstrained array, the minimum value
3088 -- for length is always zero.
3097 -- No special handling for other attributes
3098 -- Probably more opportunities exist here ???
3105 -- For type conversion from one discrete type to another, we
3106 -- can refine the range using the converted value.
3108 when N_Type_Conversion
=>
3109 Determine_Range
(Expression
(N
), OK1
, Lor
, Hir
);
3111 -- Nothing special to do for all other expression kinds
3119 -- At this stage, if OK1 is true, then we know that the actual
3120 -- result of the computed expression is in the range Lor .. Hir.
3121 -- We can use this to restrict the possible range of results.
3125 -- If the refined value of the low bound is greater than the
3126 -- type high bound, then reset it to the more restrictive
3127 -- value. However, we do NOT do this for the case of a modular
3128 -- type where the possible upper bound on the value is above the
3129 -- base type high bound, because that means the result could wrap.
3132 and then not (Is_Modular_Integer_Type
(Typ
)
3133 and then Hir
> Hbound
)
3138 -- Similarly, if the refined value of the high bound is less
3139 -- than the value so far, then reset it to the more restrictive
3140 -- value. Again, we do not do this if the refined low bound is
3141 -- negative for a modular type, since this would wrap.
3144 and then not (Is_Modular_Integer_Type
(Typ
)
3145 and then Lor
< Uint_0
)
3151 -- Set cache entry for future call and we are all done
3153 Determine_Range_Cache_N
(Cindex
) := N
;
3154 Determine_Range_Cache_Lo
(Cindex
) := Lo
;
3155 Determine_Range_Cache_Hi
(Cindex
) := Hi
;
3158 -- If any exception occurs, it means that we have some bug in the compiler
3159 -- possibly triggered by a previous error, or by some unforseen peculiar
3160 -- occurrence. However, this is only an optimization attempt, so there is
3161 -- really no point in crashing the compiler. Instead we just decide, too
3162 -- bad, we can't figure out a range in this case after all.
3167 -- Debug flag K disables this behavior (useful for debugging)
3169 if Debug_Flag_K
then
3177 end Determine_Range
;
3179 ------------------------------------
3180 -- Discriminant_Checks_Suppressed --
3181 ------------------------------------
3183 function Discriminant_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3186 if Is_Unchecked_Union
(E
) then
3188 elsif Checks_May_Be_Suppressed
(E
) then
3189 return Is_Check_Suppressed
(E
, Discriminant_Check
);
3193 return Scope_Suppress
(Discriminant_Check
);
3194 end Discriminant_Checks_Suppressed
;
3196 --------------------------------
3197 -- Division_Checks_Suppressed --
3198 --------------------------------
3200 function Division_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3202 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
3203 return Is_Check_Suppressed
(E
, Division_Check
);
3205 return Scope_Suppress
(Division_Check
);
3207 end Division_Checks_Suppressed
;
3209 -----------------------------------
3210 -- Elaboration_Checks_Suppressed --
3211 -----------------------------------
3213 function Elaboration_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3216 if Kill_Elaboration_Checks
(E
) then
3218 elsif Checks_May_Be_Suppressed
(E
) then
3219 return Is_Check_Suppressed
(E
, Elaboration_Check
);
3223 return Scope_Suppress
(Elaboration_Check
);
3224 end Elaboration_Checks_Suppressed
;
3226 ---------------------------
3227 -- Enable_Overflow_Check --
3228 ---------------------------
3230 procedure Enable_Overflow_Check
(N
: Node_Id
) is
3231 Typ
: constant Entity_Id
:= Base_Type
(Etype
(N
));
3240 if Debug_Flag_CC
then
3241 w
("Enable_Overflow_Check for node ", Int
(N
));
3242 Write_Str
(" Source location = ");
3247 -- Nothing to do if the range of the result is known OK. We skip
3248 -- this for conversions, since the caller already did the check,
3249 -- and in any case the condition for deleting the check for a
3250 -- type conversion is different in any case.
3252 if Nkind
(N
) /= N_Type_Conversion
then
3253 Determine_Range
(N
, OK
, Lo
, Hi
);
3255 -- Note in the test below that we assume that if a bound of the
3256 -- range is equal to that of the type. That's not quite accurate
3257 -- but we do this for the following reasons:
3259 -- a) The way that Determine_Range works, it will typically report
3260 -- the bounds of the value as being equal to the bounds of the
3261 -- type, because it either can't tell anything more precise, or
3262 -- does not think it is worth the effort to be more precise.
3264 -- b) It is very unusual to have a situation in which this would
3265 -- generate an unnecessary overflow check (an example would be
3266 -- a subtype with a range 0 .. Integer'Last - 1 to which the
3267 -- literal value one is added.
3269 -- c) The alternative is a lot of special casing in this routine
3270 -- which would partially duplicate Determine_Range processing.
3273 and then Lo
> Expr_Value
(Type_Low_Bound
(Typ
))
3274 and then Hi
< Expr_Value
(Type_High_Bound
(Typ
))
3276 if Debug_Flag_CC
then
3277 w
("No overflow check required");
3284 -- If not in optimizing mode, set flag and we are done. We are also
3285 -- done (and just set the flag) if the type is not a discrete type,
3286 -- since it is not worth the effort to eliminate checks for other
3287 -- than discrete types. In addition, we take this same path if we
3288 -- have stored the maximum number of checks possible already (a
3289 -- very unlikely situation, but we do not want to blow up!)
3291 if Optimization_Level
= 0
3292 or else not Is_Discrete_Type
(Etype
(N
))
3293 or else Num_Saved_Checks
= Saved_Checks
'Last
3295 Set_Do_Overflow_Check
(N
, True);
3297 if Debug_Flag_CC
then
3298 w
("Optimization off");
3304 -- Otherwise evaluate and check the expression
3309 Target_Type
=> Empty
,
3315 if Debug_Flag_CC
then
3316 w
("Called Find_Check");
3320 w
(" Check_Num = ", Chk
);
3321 w
(" Ent = ", Int
(Ent
));
3322 Write_Str
(" Ofs = ");
3327 -- If check is not of form to optimize, then set flag and we are done
3330 Set_Do_Overflow_Check
(N
, True);
3334 -- If check is already performed, then return without setting flag
3337 if Debug_Flag_CC
then
3338 w
("Check suppressed!");
3344 -- Here we will make a new entry for the new check
3346 Set_Do_Overflow_Check
(N
, True);
3347 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
3348 Saved_Checks
(Num_Saved_Checks
) :=
3353 Target_Type
=> Empty
);
3355 if Debug_Flag_CC
then
3356 w
("Make new entry, check number = ", Num_Saved_Checks
);
3357 w
(" Entity = ", Int
(Ent
));
3358 Write_Str
(" Offset = ");
3360 w
(" Check_Type = O");
3361 w
(" Target_Type = Empty");
3364 -- If we get an exception, then something went wrong, probably because
3365 -- of an error in the structure of the tree due to an incorrect program.
3366 -- Or it may be a bug in the optimization circuit. In either case the
3367 -- safest thing is simply to set the check flag unconditionally.
3371 Set_Do_Overflow_Check
(N
, True);
3373 if Debug_Flag_CC
then
3374 w
(" exception occurred, overflow flag set");
3378 end Enable_Overflow_Check
;
3380 ------------------------
3381 -- Enable_Range_Check --
3382 ------------------------
3384 procedure Enable_Range_Check
(N
: Node_Id
) is
3393 -- Return if unchecked type conversion with range check killed.
3394 -- In this case we never set the flag (that's what Kill_Range_Check
3397 if Nkind
(N
) = N_Unchecked_Type_Conversion
3398 and then Kill_Range_Check
(N
)
3403 -- Debug trace output
3405 if Debug_Flag_CC
then
3406 w
("Enable_Range_Check for node ", Int
(N
));
3407 Write_Str
(" Source location = ");
3412 -- If not in optimizing mode, set flag and we are done. We are also
3413 -- done (and just set the flag) if the type is not a discrete type,
3414 -- since it is not worth the effort to eliminate checks for other
3415 -- than discrete types. In addition, we take this same path if we
3416 -- have stored the maximum number of checks possible already (a
3417 -- very unlikely situation, but we do not want to blow up!)
3419 if Optimization_Level
= 0
3420 or else No
(Etype
(N
))
3421 or else not Is_Discrete_Type
(Etype
(N
))
3422 or else Num_Saved_Checks
= Saved_Checks
'Last
3424 Set_Do_Range_Check
(N
, True);
3426 if Debug_Flag_CC
then
3427 w
("Optimization off");
3433 -- Otherwise find out the target type
3437 -- For assignment, use left side subtype
3439 if Nkind
(P
) = N_Assignment_Statement
3440 and then Expression
(P
) = N
3442 Ttyp
:= Etype
(Name
(P
));
3444 -- For indexed component, use subscript subtype
3446 elsif Nkind
(P
) = N_Indexed_Component
then
3453 Atyp
:= Etype
(Prefix
(P
));
3455 if Is_Access_Type
(Atyp
) then
3456 Atyp
:= Designated_Type
(Atyp
);
3458 -- If the prefix is an access to an unconstrained array,
3459 -- perform check unconditionally: it depends on the bounds
3460 -- of an object and we cannot currently recognize whether
3461 -- the test may be redundant.
3463 if not Is_Constrained
(Atyp
) then
3464 Set_Do_Range_Check
(N
, True);
3469 Indx
:= First_Index
(Atyp
);
3470 Subs
:= First
(Expressions
(P
));
3473 Ttyp
:= Etype
(Indx
);
3482 -- For now, ignore all other cases, they are not so interesting
3485 if Debug_Flag_CC
then
3486 w
(" target type not found, flag set");
3489 Set_Do_Range_Check
(N
, True);
3493 -- Evaluate and check the expression
3498 Target_Type
=> Ttyp
,
3504 if Debug_Flag_CC
then
3505 w
("Called Find_Check");
3506 w
("Target_Typ = ", Int
(Ttyp
));
3510 w
(" Check_Num = ", Chk
);
3511 w
(" Ent = ", Int
(Ent
));
3512 Write_Str
(" Ofs = ");
3517 -- If check is not of form to optimize, then set flag and we are done
3520 if Debug_Flag_CC
then
3521 w
(" expression not of optimizable type, flag set");
3524 Set_Do_Range_Check
(N
, True);
3528 -- If check is already performed, then return without setting flag
3531 if Debug_Flag_CC
then
3532 w
("Check suppressed!");
3538 -- Here we will make a new entry for the new check
3540 Set_Do_Range_Check
(N
, True);
3541 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
3542 Saved_Checks
(Num_Saved_Checks
) :=
3547 Target_Type
=> Ttyp
);
3549 if Debug_Flag_CC
then
3550 w
("Make new entry, check number = ", Num_Saved_Checks
);
3551 w
(" Entity = ", Int
(Ent
));
3552 Write_Str
(" Offset = ");
3554 w
(" Check_Type = R");
3555 w
(" Target_Type = ", Int
(Ttyp
));
3559 -- If we get an exception, then something went wrong, probably because
3560 -- of an error in the structure of the tree due to an incorrect program.
3561 -- Or it may be a bug in the optimization circuit. In either case the
3562 -- safest thing is simply to set the check flag unconditionally.
3566 Set_Do_Range_Check
(N
, True);
3568 if Debug_Flag_CC
then
3569 w
(" exception occurred, range flag set");
3573 end Enable_Range_Check
;
3579 procedure Ensure_Valid
(Expr
: Node_Id
; Holes_OK
: Boolean := False) is
3580 Typ
: constant Entity_Id
:= Etype
(Expr
);
3583 -- Ignore call if we are not doing any validity checking
3585 if not Validity_Checks_On
then
3588 -- Ignore call if range checks suppressed on entity in question
3590 elsif Is_Entity_Name
(Expr
)
3591 and then Range_Checks_Suppressed
(Entity
(Expr
))
3595 -- No check required if expression is from the expander, we assume
3596 -- the expander will generate whatever checks are needed. Note that
3597 -- this is not just an optimization, it avoids infinite recursions!
3599 -- Unchecked conversions must be checked, unless they are initialized
3600 -- scalar values, as in a component assignment in an init proc.
3602 -- In addition, we force a check if Force_Validity_Checks is set
3604 elsif not Comes_From_Source
(Expr
)
3605 and then not Force_Validity_Checks
3606 and then (Nkind
(Expr
) /= N_Unchecked_Type_Conversion
3607 or else Kill_Range_Check
(Expr
))
3611 -- No check required if expression is known to have valid value
3613 elsif Expr_Known_Valid
(Expr
) then
3616 -- No check required if checks off
3618 elsif Range_Checks_Suppressed
(Typ
) then
3621 -- Ignore case of enumeration with holes where the flag is set not
3622 -- to worry about holes, since no special validity check is needed
3624 elsif Is_Enumeration_Type
(Typ
)
3625 and then Has_Non_Standard_Rep
(Typ
)
3630 -- No check required on the left-hand side of an assignment.
3632 elsif Nkind
(Parent
(Expr
)) = N_Assignment_Statement
3633 and then Expr
= Name
(Parent
(Expr
))
3637 -- An annoying special case. If this is an out parameter of a scalar
3638 -- type, then the value is not going to be accessed, therefore it is
3639 -- inappropriate to do any validity check at the call site.
3642 -- Only need to worry about scalar types
3644 if Is_Scalar_Type
(Typ
) then
3654 -- Find actual argument (which may be a parameter association)
3655 -- and the parent of the actual argument (the call statement)
3660 if Nkind
(P
) = N_Parameter_Association
then
3665 -- Only need to worry if we are argument of a procedure
3666 -- call since functions don't have out parameters. If this
3667 -- is an indirect or dispatching call, get signature from
3668 -- the subprogram type.
3670 if Nkind
(P
) = N_Procedure_Call_Statement
then
3671 L
:= Parameter_Associations
(P
);
3673 if Is_Entity_Name
(Name
(P
)) then
3674 E
:= Entity
(Name
(P
));
3676 pragma Assert
(Nkind
(Name
(P
)) = N_Explicit_Dereference
);
3677 E
:= Etype
(Name
(P
));
3680 -- Only need to worry if there are indeed actuals, and
3681 -- if this could be a procedure call, otherwise we cannot
3682 -- get a match (either we are not an argument, or the
3683 -- mode of the formal is not OUT). This test also filters
3684 -- out the generic case.
3686 if Is_Non_Empty_List
(L
)
3687 and then Is_Subprogram
(E
)
3689 -- This is the loop through parameters, looking to
3690 -- see if there is an OUT parameter for which we are
3693 F
:= First_Formal
(E
);
3696 while Present
(F
) loop
3697 if Ekind
(F
) = E_Out_Parameter
and then A
= N
then
3710 -- If we fall through, a validity check is required. Note that it would
3711 -- not be good to set Do_Range_Check, even in contexts where this is
3712 -- permissible, since this flag causes checking against the target type,
3713 -- not the source type in contexts such as assignments
3715 Insert_Valid_Check
(Expr
);
3718 ----------------------
3719 -- Expr_Known_Valid --
3720 ----------------------
3722 function Expr_Known_Valid
(Expr
: Node_Id
) return Boolean is
3723 Typ
: constant Entity_Id
:= Etype
(Expr
);
3726 -- Non-scalar types are always consdered valid, since they never
3727 -- give rise to the issues of erroneous or bounded error behavior
3728 -- that are the concern. In formal reference manual terms the
3729 -- notion of validity only applies to scalar types.
3731 if not Is_Scalar_Type
(Typ
) then
3734 -- If no validity checking, then everything is considered valid
3736 elsif not Validity_Checks_On
then
3739 -- Floating-point types are considered valid unless floating-point
3740 -- validity checks have been specifically turned on.
3742 elsif Is_Floating_Point_Type
(Typ
)
3743 and then not Validity_Check_Floating_Point
3747 -- If the expression is the value of an object that is known to
3748 -- be valid, then clearly the expression value itself is valid.
3750 elsif Is_Entity_Name
(Expr
)
3751 and then Is_Known_Valid
(Entity
(Expr
))
3755 -- If the type is one for which all values are known valid, then
3756 -- we are sure that the value is valid except in the slightly odd
3757 -- case where the expression is a reference to a variable whose size
3758 -- has been explicitly set to a value greater than the object size.
3760 elsif Is_Known_Valid
(Typ
) then
3761 if Is_Entity_Name
(Expr
)
3762 and then Ekind
(Entity
(Expr
)) = E_Variable
3763 and then Esize
(Entity
(Expr
)) > Esize
(Typ
)
3770 -- Integer and character literals always have valid values, where
3771 -- appropriate these will be range checked in any case.
3773 elsif Nkind
(Expr
) = N_Integer_Literal
3775 Nkind
(Expr
) = N_Character_Literal
3779 -- If we have a type conversion or a qualification of a known valid
3780 -- value, then the result will always be valid.
3782 elsif Nkind
(Expr
) = N_Type_Conversion
3784 Nkind
(Expr
) = N_Qualified_Expression
3786 return Expr_Known_Valid
(Expression
(Expr
));
3788 -- The result of any function call or operator is always considered
3789 -- valid, since we assume the necessary checks are done by the call.
3791 elsif Nkind
(Expr
) in N_Binary_Op
3793 Nkind
(Expr
) in N_Unary_Op
3795 Nkind
(Expr
) = N_Function_Call
3799 -- For all other cases, we do not know the expression is valid
3804 end Expr_Known_Valid
;
3810 procedure Find_Check
3812 Check_Type
: Character;
3813 Target_Type
: Entity_Id
;
3814 Entry_OK
: out Boolean;
3815 Check_Num
: out Nat
;
3816 Ent
: out Entity_Id
;
3819 function Within_Range_Of
3820 (Target_Type
: Entity_Id
;
3821 Check_Type
: Entity_Id
) return Boolean;
3822 -- Given a requirement for checking a range against Target_Type, and
3823 -- and a range Check_Type against which a check has already been made,
3824 -- determines if the check against check type is sufficient to ensure
3825 -- that no check against Target_Type is required.
3827 ---------------------
3828 -- Within_Range_Of --
3829 ---------------------
3831 function Within_Range_Of
3832 (Target_Type
: Entity_Id
;
3833 Check_Type
: Entity_Id
) return Boolean
3836 if Target_Type
= Check_Type
then
3841 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Type
);
3842 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Type
);
3843 Clo
: constant Node_Id
:= Type_Low_Bound
(Check_Type
);
3844 Chi
: constant Node_Id
:= Type_High_Bound
(Check_Type
);
3848 or else (Compile_Time_Known_Value
(Tlo
)
3850 Compile_Time_Known_Value
(Clo
)
3852 Expr_Value
(Clo
) >= Expr_Value
(Tlo
)))
3855 or else (Compile_Time_Known_Value
(Thi
)
3857 Compile_Time_Known_Value
(Chi
)
3859 Expr_Value
(Chi
) <= Expr_Value
(Clo
)))
3867 end Within_Range_Of
;
3869 -- Start of processing for Find_Check
3872 -- Establish default, to avoid warnings from GCC.
3876 -- Case of expression is simple entity reference
3878 if Is_Entity_Name
(Expr
) then
3879 Ent
:= Entity
(Expr
);
3882 -- Case of expression is entity + known constant
3884 elsif Nkind
(Expr
) = N_Op_Add
3885 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
3886 and then Is_Entity_Name
(Left_Opnd
(Expr
))
3888 Ent
:= Entity
(Left_Opnd
(Expr
));
3889 Ofs
:= Expr_Value
(Right_Opnd
(Expr
));
3891 -- Case of expression is entity - known constant
3893 elsif Nkind
(Expr
) = N_Op_Subtract
3894 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
3895 and then Is_Entity_Name
(Left_Opnd
(Expr
))
3897 Ent
:= Entity
(Left_Opnd
(Expr
));
3898 Ofs
:= UI_Negate
(Expr_Value
(Right_Opnd
(Expr
)));
3900 -- Any other expression is not of the right form
3909 -- Come here with expression of appropriate form, check if
3910 -- entity is an appropriate one for our purposes.
3912 if (Ekind
(Ent
) = E_Variable
3914 Ekind
(Ent
) = E_Constant
3916 Ekind
(Ent
) = E_Loop_Parameter
3918 Ekind
(Ent
) = E_In_Parameter
)
3919 and then not Is_Library_Level_Entity
(Ent
)
3927 -- See if there is matching check already
3929 for J
in reverse 1 .. Num_Saved_Checks
loop
3931 SC
: Saved_Check
renames Saved_Checks
(J
);
3934 if SC
.Killed
= False
3935 and then SC
.Entity
= Ent
3936 and then SC
.Offset
= Ofs
3937 and then SC
.Check_Type
= Check_Type
3938 and then Within_Range_Of
(Target_Type
, SC
.Target_Type
)
3946 -- If we fall through entry was not found
3952 ---------------------------------
3953 -- Generate_Discriminant_Check --
3954 ---------------------------------
3956 -- Note: the code for this procedure is derived from the
3957 -- emit_discriminant_check routine a-trans.c v1.659.
3959 procedure Generate_Discriminant_Check
(N
: Node_Id
) is
3960 Loc
: constant Source_Ptr
:= Sloc
(N
);
3961 Pref
: constant Node_Id
:= Prefix
(N
);
3962 Sel
: constant Node_Id
:= Selector_Name
(N
);
3964 Orig_Comp
: constant Entity_Id
:=
3965 Original_Record_Component
(Entity
(Sel
));
3966 -- The original component to be checked
3968 Discr_Fct
: constant Entity_Id
:=
3969 Discriminant_Checking_Func
(Orig_Comp
);
3970 -- The discriminant checking function
3973 -- One discriminant to be checked in the type
3975 Real_Discr
: Entity_Id
;
3976 -- Actual discriminant in the call
3978 Pref_Type
: Entity_Id
;
3979 -- Type of relevant prefix (ignoring private/access stuff)
3982 -- List of arguments for function call
3985 -- Keep track of the formal corresponding to the actual we build
3986 -- for each discriminant, in order to be able to perform the
3987 -- necessary type conversions.
3990 -- Selected component reference for checking function argument
3993 Pref_Type
:= Etype
(Pref
);
3995 -- Force evaluation of the prefix, so that it does not get evaluated
3996 -- twice (once for the check, once for the actual reference). Such a
3997 -- double evaluation is always a potential source of inefficiency,
3998 -- and is functionally incorrect in the volatile case, or when the
3999 -- prefix may have side-effects. An entity or a component of an
4000 -- entity requires no evaluation.
4002 if Is_Entity_Name
(Pref
) then
4003 if Treat_As_Volatile
(Entity
(Pref
)) then
4004 Force_Evaluation
(Pref
, Name_Req
=> True);
4007 elsif Treat_As_Volatile
(Etype
(Pref
)) then
4008 Force_Evaluation
(Pref
, Name_Req
=> True);
4010 elsif Nkind
(Pref
) = N_Selected_Component
4011 and then Is_Entity_Name
(Prefix
(Pref
))
4016 Force_Evaluation
(Pref
, Name_Req
=> True);
4019 -- For a tagged type, use the scope of the original component to
4020 -- obtain the type, because ???
4022 if Is_Tagged_Type
(Scope
(Orig_Comp
)) then
4023 Pref_Type
:= Scope
(Orig_Comp
);
4025 -- For an untagged derived type, use the discriminants of the
4026 -- parent which have been renamed in the derivation, possibly
4027 -- by a one-to-many discriminant constraint.
4028 -- For non-tagged type, initially get the Etype of the prefix
4031 if Is_Derived_Type
(Pref_Type
)
4032 and then Number_Discriminants
(Pref_Type
) /=
4033 Number_Discriminants
(Etype
(Base_Type
(Pref_Type
)))
4035 Pref_Type
:= Etype
(Base_Type
(Pref_Type
));
4039 -- We definitely should have a checking function, This routine should
4040 -- not be called if no discriminant checking function is present.
4042 pragma Assert
(Present
(Discr_Fct
));
4044 -- Create the list of the actual parameters for the call. This list
4045 -- is the list of the discriminant fields of the record expression to
4046 -- be discriminant checked.
4049 Formal
:= First_Formal
(Discr_Fct
);
4050 Discr
:= First_Discriminant
(Pref_Type
);
4051 while Present
(Discr
) loop
4053 -- If we have a corresponding discriminant field, and a parent
4054 -- subtype is present, then we want to use the corresponding
4055 -- discriminant since this is the one with the useful value.
4057 if Present
(Corresponding_Discriminant
(Discr
))
4058 and then Ekind
(Pref_Type
) = E_Record_Type
4059 and then Present
(Parent_Subtype
(Pref_Type
))
4061 Real_Discr
:= Corresponding_Discriminant
(Discr
);
4063 Real_Discr
:= Discr
;
4066 -- Construct the reference to the discriminant
4069 Make_Selected_Component
(Loc
,
4071 Unchecked_Convert_To
(Pref_Type
,
4072 Duplicate_Subexpr
(Pref
)),
4073 Selector_Name
=> New_Occurrence_Of
(Real_Discr
, Loc
));
4075 -- Manually analyze and resolve this selected component. We really
4076 -- want it just as it appears above, and do not want the expander
4077 -- playing discriminal games etc with this reference. Then we
4078 -- append the argument to the list we are gathering.
4080 Set_Etype
(Scomp
, Etype
(Real_Discr
));
4081 Set_Analyzed
(Scomp
, True);
4082 Append_To
(Args
, Convert_To
(Etype
(Formal
), Scomp
));
4084 Next_Formal_With_Extras
(Formal
);
4085 Next_Discriminant
(Discr
);
4088 -- Now build and insert the call
4091 Make_Raise_Constraint_Error
(Loc
,
4093 Make_Function_Call
(Loc
,
4094 Name
=> New_Occurrence_Of
(Discr_Fct
, Loc
),
4095 Parameter_Associations
=> Args
),
4096 Reason
=> CE_Discriminant_Check_Failed
));
4097 end Generate_Discriminant_Check
;
4099 ---------------------------
4100 -- Generate_Index_Checks --
4101 ---------------------------
4103 procedure Generate_Index_Checks
(N
: Node_Id
) is
4104 Loc
: constant Source_Ptr
:= Sloc
(N
);
4105 A
: constant Node_Id
:= Prefix
(N
);
4111 Sub
:= First
(Expressions
(N
));
4113 while Present
(Sub
) loop
4114 if Do_Range_Check
(Sub
) then
4115 Set_Do_Range_Check
(Sub
, False);
4117 -- Force evaluation except for the case of a simple name of
4118 -- a non-volatile entity.
4120 if not Is_Entity_Name
(Sub
)
4121 or else Treat_As_Volatile
(Entity
(Sub
))
4123 Force_Evaluation
(Sub
);
4126 -- Generate a raise of constraint error with the appropriate
4127 -- reason and a condition of the form:
4129 -- Base_Type(Sub) not in array'range (subscript)
4131 -- Note that the reason we generate the conversion to the
4132 -- base type here is that we definitely want the range check
4133 -- to take place, even if it looks like the subtype is OK.
4134 -- Optimization considerations that allow us to omit the
4135 -- check have already been taken into account in the setting
4136 -- of the Do_Range_Check flag earlier on.
4141 Num
:= New_List
(Make_Integer_Literal
(Loc
, Ind
));
4145 Make_Raise_Constraint_Error
(Loc
,
4149 Convert_To
(Base_Type
(Etype
(Sub
)),
4150 Duplicate_Subexpr_Move_Checks
(Sub
)),
4152 Make_Attribute_Reference
(Loc
,
4153 Prefix
=> Duplicate_Subexpr_Move_Checks
(A
),
4154 Attribute_Name
=> Name_Range
,
4155 Expressions
=> Num
)),
4156 Reason
=> CE_Index_Check_Failed
));
4162 end Generate_Index_Checks
;
4164 --------------------------
4165 -- Generate_Range_Check --
4166 --------------------------
4168 procedure Generate_Range_Check
4170 Target_Type
: Entity_Id
;
4171 Reason
: RT_Exception_Code
)
4173 Loc
: constant Source_Ptr
:= Sloc
(N
);
4174 Source_Type
: constant Entity_Id
:= Etype
(N
);
4175 Source_Base_Type
: constant Entity_Id
:= Base_Type
(Source_Type
);
4176 Target_Base_Type
: constant Entity_Id
:= Base_Type
(Target_Type
);
4179 -- First special case, if the source type is already within the
4180 -- range of the target type, then no check is needed (probably we
4181 -- should have stopped Do_Range_Check from being set in the first
4182 -- place, but better late than later in preventing junk code!
4184 -- We do NOT apply this if the source node is a literal, since in
4185 -- this case the literal has already been labeled as having the
4186 -- subtype of the target.
4188 if In_Subrange_Of
(Source_Type
, Target_Type
)
4190 (Nkind
(N
) = N_Integer_Literal
4192 Nkind
(N
) = N_Real_Literal
4194 Nkind
(N
) = N_Character_Literal
4197 and then Ekind
(Entity
(N
)) = E_Enumeration_Literal
))
4202 -- We need a check, so force evaluation of the node, so that it does
4203 -- not get evaluated twice (once for the check, once for the actual
4204 -- reference). Such a double evaluation is always a potential source
4205 -- of inefficiency, and is functionally incorrect in the volatile case.
4207 if not Is_Entity_Name
(N
)
4208 or else Treat_As_Volatile
(Entity
(N
))
4210 Force_Evaluation
(N
);
4213 -- The easiest case is when Source_Base_Type and Target_Base_Type
4214 -- are the same since in this case we can simply do a direct
4215 -- check of the value of N against the bounds of Target_Type.
4217 -- [constraint_error when N not in Target_Type]
4219 -- Note: this is by far the most common case, for example all cases of
4220 -- checks on the RHS of assignments are in this category, but not all
4221 -- cases are like this. Notably conversions can involve two types.
4223 if Source_Base_Type
= Target_Base_Type
then
4225 Make_Raise_Constraint_Error
(Loc
,
4228 Left_Opnd
=> Duplicate_Subexpr
(N
),
4229 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
4232 -- Next test for the case where the target type is within the bounds
4233 -- of the base type of the source type, since in this case we can
4234 -- simply convert these bounds to the base type of T to do the test.
4236 -- [constraint_error when N not in
4237 -- Source_Base_Type (Target_Type'First)
4239 -- Source_Base_Type(Target_Type'Last))]
4241 -- The conversions will always work and need no check.
4243 elsif In_Subrange_Of
(Target_Type
, Source_Base_Type
) then
4245 Make_Raise_Constraint_Error
(Loc
,
4248 Left_Opnd
=> Duplicate_Subexpr
(N
),
4253 Convert_To
(Source_Base_Type
,
4254 Make_Attribute_Reference
(Loc
,
4256 New_Occurrence_Of
(Target_Type
, Loc
),
4257 Attribute_Name
=> Name_First
)),
4260 Convert_To
(Source_Base_Type
,
4261 Make_Attribute_Reference
(Loc
,
4263 New_Occurrence_Of
(Target_Type
, Loc
),
4264 Attribute_Name
=> Name_Last
)))),
4267 -- Note that at this stage we now that the Target_Base_Type is
4268 -- not in the range of the Source_Base_Type (since even the
4269 -- Target_Type itself is not in this range). It could still be
4270 -- the case that the Source_Type is in range of the target base
4271 -- type, since we have not checked that case.
4273 -- If that is the case, we can freely convert the source to the
4274 -- target, and then test the target result against the bounds.
4276 elsif In_Subrange_Of
(Source_Type
, Target_Base_Type
) then
4278 -- We make a temporary to hold the value of the converted
4279 -- value (converted to the base type), and then we will
4280 -- do the test against this temporary.
4282 -- Tnn : constant Target_Base_Type := Target_Base_Type (N);
4283 -- [constraint_error when Tnn not in Target_Type]
4285 -- Then the conversion itself is replaced by an occurrence of Tnn
4288 Tnn
: constant Entity_Id
:=
4289 Make_Defining_Identifier
(Loc
,
4290 Chars
=> New_Internal_Name
('T'));
4293 Insert_Actions
(N
, New_List
(
4294 Make_Object_Declaration
(Loc
,
4295 Defining_Identifier
=> Tnn
,
4296 Object_Definition
=>
4297 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4298 Constant_Present
=> True,
4300 Make_Type_Conversion
(Loc
,
4301 Subtype_Mark
=> New_Occurrence_Of
(Target_Base_Type
, Loc
),
4302 Expression
=> Duplicate_Subexpr
(N
))),
4304 Make_Raise_Constraint_Error
(Loc
,
4307 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
4308 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
4310 Reason
=> Reason
)));
4312 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
4315 -- At this stage, we know that we have two scalar types, which are
4316 -- directly convertible, and where neither scalar type has a base
4317 -- range that is in the range of the other scalar type.
4319 -- The only way this can happen is with a signed and unsigned type.
4320 -- So test for these two cases:
4323 -- Case of the source is unsigned and the target is signed
4325 if Is_Unsigned_Type
(Source_Base_Type
)
4326 and then not Is_Unsigned_Type
(Target_Base_Type
)
4328 -- If the source is unsigned and the target is signed, then we
4329 -- know that the source is not shorter than the target (otherwise
4330 -- the source base type would be in the target base type range).
4332 -- In other words, the unsigned type is either the same size
4333 -- as the target, or it is larger. It cannot be smaller.
4336 (Esize
(Source_Base_Type
) >= Esize
(Target_Base_Type
));
4338 -- We only need to check the low bound if the low bound of the
4339 -- target type is non-negative. If the low bound of the target
4340 -- type is negative, then we know that we will fit fine.
4342 -- If the high bound of the target type is negative, then we
4343 -- know we have a constraint error, since we can't possibly
4344 -- have a negative source.
4346 -- With these two checks out of the way, we can do the check
4347 -- using the source type safely
4349 -- This is definitely the most annoying case!
4351 -- [constraint_error
4352 -- when (Target_Type'First >= 0
4354 -- N < Source_Base_Type (Target_Type'First))
4355 -- or else Target_Type'Last < 0
4356 -- or else N > Source_Base_Type (Target_Type'Last)];
4358 -- We turn off all checks since we know that the conversions
4359 -- will work fine, given the guards for negative values.
4362 Make_Raise_Constraint_Error
(Loc
,
4368 Left_Opnd
=> Make_Op_Ge
(Loc
,
4370 Make_Attribute_Reference
(Loc
,
4372 New_Occurrence_Of
(Target_Type
, Loc
),
4373 Attribute_Name
=> Name_First
),
4374 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
4378 Left_Opnd
=> Duplicate_Subexpr
(N
),
4380 Convert_To
(Source_Base_Type
,
4381 Make_Attribute_Reference
(Loc
,
4383 New_Occurrence_Of
(Target_Type
, Loc
),
4384 Attribute_Name
=> Name_First
)))),
4389 Make_Attribute_Reference
(Loc
,
4390 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
4391 Attribute_Name
=> Name_Last
),
4392 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
))),
4396 Left_Opnd
=> Duplicate_Subexpr
(N
),
4398 Convert_To
(Source_Base_Type
,
4399 Make_Attribute_Reference
(Loc
,
4400 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
4401 Attribute_Name
=> Name_Last
)))),
4404 Suppress
=> All_Checks
);
4406 -- Only remaining possibility is that the source is signed and
4407 -- the target is unsigned
4410 pragma Assert
(not Is_Unsigned_Type
(Source_Base_Type
)
4411 and then Is_Unsigned_Type
(Target_Base_Type
));
4413 -- If the source is signed and the target is unsigned, then
4414 -- we know that the target is not shorter than the source
4415 -- (otherwise the target base type would be in the source
4416 -- base type range).
4418 -- In other words, the unsigned type is either the same size
4419 -- as the target, or it is larger. It cannot be smaller.
4421 -- Clearly we have an error if the source value is negative
4422 -- since no unsigned type can have negative values. If the
4423 -- source type is non-negative, then the check can be done
4424 -- using the target type.
4426 -- Tnn : constant Target_Base_Type (N) := Target_Type;
4428 -- [constraint_error
4429 -- when N < 0 or else Tnn not in Target_Type];
4431 -- We turn off all checks for the conversion of N to the
4432 -- target base type, since we generate the explicit check
4433 -- to ensure that the value is non-negative
4436 Tnn
: constant Entity_Id
:=
4437 Make_Defining_Identifier
(Loc
,
4438 Chars
=> New_Internal_Name
('T'));
4441 Insert_Actions
(N
, New_List
(
4442 Make_Object_Declaration
(Loc
,
4443 Defining_Identifier
=> Tnn
,
4444 Object_Definition
=>
4445 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4446 Constant_Present
=> True,
4448 Make_Type_Conversion
(Loc
,
4450 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4451 Expression
=> Duplicate_Subexpr
(N
))),
4453 Make_Raise_Constraint_Error
(Loc
,
4458 Left_Opnd
=> Duplicate_Subexpr
(N
),
4459 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
4463 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
4465 New_Occurrence_Of
(Target_Type
, Loc
))),
4468 Suppress
=> All_Checks
);
4470 -- Set the Etype explicitly, because Insert_Actions may
4471 -- have placed the declaration in the freeze list for an
4472 -- enclosing construct, and thus it is not analyzed yet.
4474 Set_Etype
(Tnn
, Target_Base_Type
);
4475 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
4479 end Generate_Range_Check
;
4481 ---------------------
4482 -- Get_Discriminal --
4483 ---------------------
4485 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
is
4486 Loc
: constant Source_Ptr
:= Sloc
(E
);
4491 -- The entity E is the type of a private component of the protected
4492 -- type, or the type of a renaming of that component within a protected
4493 -- operation of that type.
4497 if Ekind
(Sc
) /= E_Protected_Type
then
4500 if Ekind
(Sc
) /= E_Protected_Type
then
4505 D
:= First_Discriminant
(Sc
);
4508 and then Chars
(D
) /= Chars
(Bound
)
4510 Next_Discriminant
(D
);
4513 return New_Occurrence_Of
(Discriminal
(D
), Loc
);
4514 end Get_Discriminal
;
4520 function Guard_Access
4523 Ck_Node
: Node_Id
) return Node_Id
4526 if Nkind
(Cond
) = N_Or_Else
then
4527 Set_Paren_Count
(Cond
, 1);
4530 if Nkind
(Ck_Node
) = N_Allocator
then
4537 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
4538 Right_Opnd
=> Make_Null
(Loc
)),
4539 Right_Opnd
=> Cond
);
4543 -----------------------------
4544 -- Index_Checks_Suppressed --
4545 -----------------------------
4547 function Index_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4549 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4550 return Is_Check_Suppressed
(E
, Index_Check
);
4552 return Scope_Suppress
(Index_Check
);
4554 end Index_Checks_Suppressed
;
4560 procedure Initialize
is
4562 for J
in Determine_Range_Cache_N
'Range loop
4563 Determine_Range_Cache_N
(J
) := Empty
;
4567 -------------------------
4568 -- Insert_Range_Checks --
4569 -------------------------
4571 procedure Insert_Range_Checks
4572 (Checks
: Check_Result
;
4574 Suppress_Typ
: Entity_Id
;
4575 Static_Sloc
: Source_Ptr
:= No_Location
;
4576 Flag_Node
: Node_Id
:= Empty
;
4577 Do_Before
: Boolean := False)
4579 Internal_Flag_Node
: Node_Id
:= Flag_Node
;
4580 Internal_Static_Sloc
: Source_Ptr
:= Static_Sloc
;
4582 Check_Node
: Node_Id
;
4583 Checks_On
: constant Boolean :=
4584 (not Index_Checks_Suppressed
(Suppress_Typ
))
4586 (not Range_Checks_Suppressed
(Suppress_Typ
));
4589 -- For now we just return if Checks_On is false, however this should
4590 -- be enhanced to check for an always True value in the condition
4591 -- and to generate a compilation warning???
4593 if not Expander_Active
or else not Checks_On
then
4597 if Static_Sloc
= No_Location
then
4598 Internal_Static_Sloc
:= Sloc
(Node
);
4601 if No
(Flag_Node
) then
4602 Internal_Flag_Node
:= Node
;
4605 for J
in 1 .. 2 loop
4606 exit when No
(Checks
(J
));
4608 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
4609 and then Present
(Condition
(Checks
(J
)))
4611 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
4612 Check_Node
:= Checks
(J
);
4613 Mark_Rewrite_Insertion
(Check_Node
);
4616 Insert_Before_And_Analyze
(Node
, Check_Node
);
4618 Insert_After_And_Analyze
(Node
, Check_Node
);
4621 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
4626 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
4627 Reason
=> CE_Range_Check_Failed
);
4628 Mark_Rewrite_Insertion
(Check_Node
);
4631 Insert_Before_And_Analyze
(Node
, Check_Node
);
4633 Insert_After_And_Analyze
(Node
, Check_Node
);
4637 end Insert_Range_Checks
;
4639 ------------------------
4640 -- Insert_Valid_Check --
4641 ------------------------
4643 procedure Insert_Valid_Check
(Expr
: Node_Id
) is
4644 Loc
: constant Source_Ptr
:= Sloc
(Expr
);
4648 -- Do not insert if checks off, or if not checking validity
4650 if Range_Checks_Suppressed
(Etype
(Expr
))
4651 or else (not Validity_Checks_On
)
4656 -- If we have a checked conversion, then validity check applies to
4657 -- the expression inside the conversion, not the result, since if
4658 -- the expression inside is valid, then so is the conversion result.
4661 while Nkind
(Exp
) = N_Type_Conversion
loop
4662 Exp
:= Expression
(Exp
);
4665 -- Insert the validity check. Note that we do this with validity
4666 -- checks turned off, to avoid recursion, we do not want validity
4667 -- checks on the validity checking code itself!
4669 Validity_Checks_On
:= False;
4672 Make_Raise_Constraint_Error
(Loc
,
4676 Make_Attribute_Reference
(Loc
,
4678 Duplicate_Subexpr_No_Checks
(Exp
, Name_Req
=> True),
4679 Attribute_Name
=> Name_Valid
)),
4680 Reason
=> CE_Invalid_Data
),
4681 Suppress
=> All_Checks
);
4682 Validity_Checks_On
:= True;
4683 end Insert_Valid_Check
;
4685 ----------------------------------
4686 -- Install_Null_Excluding_Check --
4687 ----------------------------------
4689 procedure Install_Null_Excluding_Check
(N
: Node_Id
) is
4690 Loc
: constant Source_Ptr
:= Sloc
(N
);
4691 Etyp
: constant Entity_Id
:= Etype
(N
);
4694 pragma Assert
(Is_Access_Type
(Etyp
));
4696 -- Don't need access check if: 1) we are analyzing a generic, 2) it is
4697 -- known to be non-null, or 3) the check was suppressed on the type
4700 or else Access_Checks_Suppressed
(Etyp
)
4704 -- Otherwise install access check
4708 Make_Raise_Constraint_Error
(Loc
,
4711 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(N
),
4712 Right_Opnd
=> Make_Null
(Loc
)),
4713 Reason
=> CE_Access_Check_Failed
));
4715 end Install_Null_Excluding_Check
;
4717 --------------------------
4718 -- Install_Static_Check --
4719 --------------------------
4721 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
) is
4722 Stat
: constant Boolean := Is_Static_Expression
(R_Cno
);
4723 Typ
: constant Entity_Id
:= Etype
(R_Cno
);
4727 Make_Raise_Constraint_Error
(Loc
,
4728 Reason
=> CE_Range_Check_Failed
));
4729 Set_Analyzed
(R_Cno
);
4730 Set_Etype
(R_Cno
, Typ
);
4731 Set_Raises_Constraint_Error
(R_Cno
);
4732 Set_Is_Static_Expression
(R_Cno
, Stat
);
4733 end Install_Static_Check
;
4735 ---------------------
4736 -- Kill_All_Checks --
4737 ---------------------
4739 procedure Kill_All_Checks
is
4741 if Debug_Flag_CC
then
4742 w
("Kill_All_Checks");
4745 -- We reset the number of saved checks to zero, and also modify
4746 -- all stack entries for statement ranges to indicate that the
4747 -- number of checks at each level is now zero.
4749 Num_Saved_Checks
:= 0;
4751 for J
in 1 .. Saved_Checks_TOS
loop
4752 Saved_Checks_Stack
(J
) := 0;
4754 end Kill_All_Checks
;
4760 procedure Kill_Checks
(V
: Entity_Id
) is
4762 if Debug_Flag_CC
then
4763 w
("Kill_Checks for entity", Int
(V
));
4766 for J
in 1 .. Num_Saved_Checks
loop
4767 if Saved_Checks
(J
).Entity
= V
then
4768 if Debug_Flag_CC
then
4769 w
(" Checks killed for saved check ", J
);
4772 Saved_Checks
(J
).Killed
:= True;
4777 ------------------------------
4778 -- Length_Checks_Suppressed --
4779 ------------------------------
4781 function Length_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4783 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4784 return Is_Check_Suppressed
(E
, Length_Check
);
4786 return Scope_Suppress
(Length_Check
);
4788 end Length_Checks_Suppressed
;
4790 --------------------------------
4791 -- Overflow_Checks_Suppressed --
4792 --------------------------------
4794 function Overflow_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
, Overflow_Check
);
4799 return Scope_Suppress
(Overflow_Check
);
4801 end Overflow_Checks_Suppressed
;
4807 function Range_Check
4809 Target_Typ
: Entity_Id
;
4810 Source_Typ
: Entity_Id
:= Empty
;
4811 Warn_Node
: Node_Id
:= Empty
) return Check_Result
4814 return Selected_Range_Checks
4815 (Ck_Node
, Target_Typ
, Source_Typ
, Warn_Node
);
4818 -----------------------------
4819 -- Range_Checks_Suppressed --
4820 -----------------------------
4822 function Range_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4826 -- Note: for now we always suppress range checks on Vax float types,
4827 -- since Gigi does not know how to generate these checks.
4829 if Vax_Float
(E
) then
4831 elsif Kill_Range_Checks
(E
) then
4833 elsif Checks_May_Be_Suppressed
(E
) then
4834 return Is_Check_Suppressed
(E
, Range_Check
);
4838 return Scope_Suppress
(Range_Check
);
4839 end Range_Checks_Suppressed
;
4845 procedure Remove_Checks
(Expr
: Node_Id
) is
4846 Discard
: Traverse_Result
;
4847 pragma Warnings
(Off
, Discard
);
4849 function Process
(N
: Node_Id
) return Traverse_Result
;
4850 -- Process a single node during the traversal
4852 function Traverse
is new Traverse_Func
(Process
);
4853 -- The traversal function itself
4859 function Process
(N
: Node_Id
) return Traverse_Result
is
4861 if Nkind
(N
) not in N_Subexpr
then
4865 Set_Do_Range_Check
(N
, False);
4869 Discard
:= Traverse
(Left_Opnd
(N
));
4872 when N_Attribute_Reference
=>
4873 Set_Do_Overflow_Check
(N
, False);
4875 when N_Function_Call
=>
4876 Set_Do_Tag_Check
(N
, False);
4879 Set_Do_Overflow_Check
(N
, False);
4883 Set_Do_Division_Check
(N
, False);
4886 Set_Do_Length_Check
(N
, False);
4889 Set_Do_Division_Check
(N
, False);
4892 Set_Do_Length_Check
(N
, False);
4895 Set_Do_Division_Check
(N
, False);
4898 Set_Do_Length_Check
(N
, False);
4905 Discard
:= Traverse
(Left_Opnd
(N
));
4908 when N_Selected_Component
=>
4909 Set_Do_Discriminant_Check
(N
, False);
4911 when N_Type_Conversion
=>
4912 Set_Do_Length_Check
(N
, False);
4913 Set_Do_Tag_Check
(N
, False);
4914 Set_Do_Overflow_Check
(N
, False);
4923 -- Start of processing for Remove_Checks
4926 Discard
:= Traverse
(Expr
);
4929 ----------------------------
4930 -- Selected_Length_Checks --
4931 ----------------------------
4933 function Selected_Length_Checks
4935 Target_Typ
: Entity_Id
;
4936 Source_Typ
: Entity_Id
;
4937 Warn_Node
: Node_Id
) return Check_Result
4939 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
4942 Expr_Actual
: Node_Id
;
4944 Cond
: Node_Id
:= Empty
;
4945 Do_Access
: Boolean := False;
4946 Wnode
: Node_Id
:= Warn_Node
;
4947 Ret_Result
: Check_Result
:= (Empty
, Empty
);
4948 Num_Checks
: Natural := 0;
4950 procedure Add_Check
(N
: Node_Id
);
4951 -- Adds the action given to Ret_Result if N is non-Empty
4953 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
;
4954 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
4955 -- Comments required ???
4957 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean;
4958 -- True for equal literals and for nodes that denote the same constant
4959 -- entity, even if its value is not a static constant. This includes the
4960 -- case of a discriminal reference within an init proc. Removes some
4961 -- obviously superfluous checks.
4963 function Length_E_Cond
4964 (Exptyp
: Entity_Id
;
4966 Indx
: Nat
) return Node_Id
;
4967 -- Returns expression to compute:
4968 -- Typ'Length /= Exptyp'Length
4970 function Length_N_Cond
4973 Indx
: Nat
) return Node_Id
;
4974 -- Returns expression to compute:
4975 -- Typ'Length /= Expr'Length
4981 procedure Add_Check
(N
: Node_Id
) is
4985 -- For now, ignore attempt to place more than 2 checks ???
4987 if Num_Checks
= 2 then
4991 pragma Assert
(Num_Checks
<= 1);
4992 Num_Checks
:= Num_Checks
+ 1;
4993 Ret_Result
(Num_Checks
) := N
;
5001 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
is
5002 Pt
: constant Entity_Id
:= Scope
(Scope
(E
));
5004 E1
: Entity_Id
:= E
;
5007 if Ekind
(Scope
(E
)) = E_Record_Type
5008 and then Has_Discriminants
(Scope
(E
))
5010 N
:= Build_Discriminal_Subtype_Of_Component
(E
);
5013 Insert_Action
(Ck_Node
, N
);
5014 E1
:= Defining_Identifier
(N
);
5018 if Ekind
(E1
) = E_String_Literal_Subtype
then
5020 Make_Integer_Literal
(Loc
,
5021 Intval
=> String_Literal_Length
(E1
));
5023 elsif Ekind
(Pt
) = E_Protected_Type
5024 and then Has_Discriminants
(Pt
)
5025 and then Has_Completion
(Pt
)
5026 and then not Inside_Init_Proc
5029 -- If the type whose length is needed is a private component
5030 -- constrained by a discriminant, we must expand the 'Length
5031 -- attribute into an explicit computation, using the discriminal
5032 -- of the current protected operation. This is because the actual
5033 -- type of the prival is constructed after the protected opera-
5034 -- tion has been fully expanded.
5037 Indx_Type
: Node_Id
;
5040 Do_Expand
: Boolean := False;
5043 Indx_Type
:= First_Index
(E
);
5045 for J
in 1 .. Indx
- 1 loop
5046 Next_Index
(Indx_Type
);
5049 Get_Index_Bounds
(Indx_Type
, Lo
, Hi
);
5051 if Nkind
(Lo
) = N_Identifier
5052 and then Ekind
(Entity
(Lo
)) = E_In_Parameter
5054 Lo
:= Get_Discriminal
(E
, Lo
);
5058 if Nkind
(Hi
) = N_Identifier
5059 and then Ekind
(Entity
(Hi
)) = E_In_Parameter
5061 Hi
:= Get_Discriminal
(E
, Hi
);
5066 if not Is_Entity_Name
(Lo
) then
5067 Lo
:= Duplicate_Subexpr_No_Checks
(Lo
);
5070 if not Is_Entity_Name
(Hi
) then
5071 Lo
:= Duplicate_Subexpr_No_Checks
(Hi
);
5077 Make_Op_Subtract
(Loc
,
5081 Right_Opnd
=> Make_Integer_Literal
(Loc
, 1));
5086 Make_Attribute_Reference
(Loc
,
5087 Attribute_Name
=> Name_Length
,
5089 New_Occurrence_Of
(E1
, Loc
));
5092 Set_Expressions
(N
, New_List
(
5093 Make_Integer_Literal
(Loc
, Indx
)));
5102 Make_Attribute_Reference
(Loc
,
5103 Attribute_Name
=> Name_Length
,
5105 New_Occurrence_Of
(E1
, Loc
));
5108 Set_Expressions
(N
, New_List
(
5109 Make_Integer_Literal
(Loc
, Indx
)));
5121 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5124 Make_Attribute_Reference
(Loc
,
5125 Attribute_Name
=> Name_Length
,
5127 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5128 Expressions
=> New_List
(
5129 Make_Integer_Literal
(Loc
, Indx
)));
5137 function Length_E_Cond
5138 (Exptyp
: Entity_Id
;
5140 Indx
: Nat
) return Node_Id
5145 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
5146 Right_Opnd
=> Get_E_Length
(Exptyp
, Indx
));
5154 function Length_N_Cond
5157 Indx
: Nat
) return Node_Id
5162 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
5163 Right_Opnd
=> Get_N_Length
(Expr
, Indx
));
5167 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean is
5170 (Nkind
(L
) = N_Integer_Literal
5171 and then Nkind
(R
) = N_Integer_Literal
5172 and then Intval
(L
) = Intval
(R
))
5176 and then Ekind
(Entity
(L
)) = E_Constant
5177 and then ((Is_Entity_Name
(R
)
5178 and then Entity
(L
) = Entity
(R
))
5180 (Nkind
(R
) = N_Type_Conversion
5181 and then Is_Entity_Name
(Expression
(R
))
5182 and then Entity
(L
) = Entity
(Expression
(R
)))))
5186 and then Ekind
(Entity
(R
)) = E_Constant
5187 and then Nkind
(L
) = N_Type_Conversion
5188 and then Is_Entity_Name
(Expression
(L
))
5189 and then Entity
(R
) = Entity
(Expression
(L
)))
5193 and then Is_Entity_Name
(R
)
5194 and then Entity
(L
) = Entity
(R
)
5195 and then Ekind
(Entity
(L
)) = E_In_Parameter
5196 and then Inside_Init_Proc
);
5199 -- Start of processing for Selected_Length_Checks
5202 if not Expander_Active
then
5206 if Target_Typ
= Any_Type
5207 or else Target_Typ
= Any_Composite
5208 or else Raises_Constraint_Error
(Ck_Node
)
5217 T_Typ
:= Target_Typ
;
5219 if No
(Source_Typ
) then
5220 S_Typ
:= Etype
(Ck_Node
);
5222 S_Typ
:= Source_Typ
;
5225 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
5229 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
5230 S_Typ
:= Designated_Type
(S_Typ
);
5231 T_Typ
:= Designated_Type
(T_Typ
);
5234 -- A simple optimization
5236 if Nkind
(Ck_Node
) = N_Null
then
5241 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
5242 if Is_Constrained
(T_Typ
) then
5244 -- The checking code to be generated will freeze the
5245 -- corresponding array type. However, we must freeze the
5246 -- type now, so that the freeze node does not appear within
5247 -- the generated condional expression, but ahead of it.
5249 Freeze_Before
(Ck_Node
, T_Typ
);
5251 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
5252 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
5254 if Is_Access_Type
(Exptyp
) then
5255 Exptyp
:= Designated_Type
(Exptyp
);
5258 -- String_Literal case. This needs to be handled specially be-
5259 -- cause no index types are available for string literals. The
5260 -- condition is simply:
5262 -- T_Typ'Length = string-literal-length
5264 if Nkind
(Expr_Actual
) = N_String_Literal
5265 and then Ekind
(Etype
(Expr_Actual
)) = E_String_Literal_Subtype
5269 Left_Opnd
=> Get_E_Length
(T_Typ
, 1),
5271 Make_Integer_Literal
(Loc
,
5273 String_Literal_Length
(Etype
(Expr_Actual
))));
5275 -- General array case. Here we have a usable actual subtype for
5276 -- the expression, and the condition is built from the two types
5279 -- T_Typ'Length /= Exptyp'Length or else
5280 -- T_Typ'Length (2) /= Exptyp'Length (2) or else
5281 -- T_Typ'Length (3) /= Exptyp'Length (3) or else
5284 elsif Is_Constrained
(Exptyp
) then
5286 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
5300 -- At the library level, we need to ensure that the
5301 -- type of the object is elaborated before the check
5302 -- itself is emitted. This is only done if the object
5303 -- is in the current compilation unit, otherwise the
5304 -- type is frozen and elaborated in its unit.
5306 if Is_Itype
(Exptyp
)
5308 Ekind
(Cunit_Entity
(Current_Sem_Unit
)) = E_Package
5310 not In_Package_Body
(Cunit_Entity
(Current_Sem_Unit
))
5311 and then In_Open_Scopes
(Scope
(Exptyp
))
5313 Ref_Node
:= Make_Itype_Reference
(Sloc
(Ck_Node
));
5314 Set_Itype
(Ref_Node
, Exptyp
);
5315 Insert_Action
(Ck_Node
, Ref_Node
);
5318 L_Index
:= First_Index
(T_Typ
);
5319 R_Index
:= First_Index
(Exptyp
);
5321 for Indx
in 1 .. Ndims
loop
5322 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
5324 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
5326 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
5327 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
5329 -- Deal with compile time length check. Note that we
5330 -- skip this in the access case, because the access
5331 -- value may be null, so we cannot know statically.
5334 and then Compile_Time_Known_Value
(L_Low
)
5335 and then Compile_Time_Known_Value
(L_High
)
5336 and then Compile_Time_Known_Value
(R_Low
)
5337 and then Compile_Time_Known_Value
(R_High
)
5339 if Expr_Value
(L_High
) >= Expr_Value
(L_Low
) then
5340 L_Length
:= Expr_Value
(L_High
) -
5341 Expr_Value
(L_Low
) + 1;
5343 L_Length
:= UI_From_Int
(0);
5346 if Expr_Value
(R_High
) >= Expr_Value
(R_Low
) then
5347 R_Length
:= Expr_Value
(R_High
) -
5348 Expr_Value
(R_Low
) + 1;
5350 R_Length
:= UI_From_Int
(0);
5353 if L_Length
> R_Length
then
5355 (Compile_Time_Constraint_Error
5356 (Wnode
, "too few elements for}?", T_Typ
));
5358 elsif L_Length
< R_Length
then
5360 (Compile_Time_Constraint_Error
5361 (Wnode
, "too many elements for}?", T_Typ
));
5364 -- The comparison for an individual index subtype
5365 -- is omitted if the corresponding index subtypes
5366 -- statically match, since the result is known to
5367 -- be true. Note that this test is worth while even
5368 -- though we do static evaluation, because non-static
5369 -- subtypes can statically match.
5372 Subtypes_Statically_Match
5373 (Etype
(L_Index
), Etype
(R_Index
))
5376 (Same_Bounds
(L_Low
, R_Low
)
5377 and then Same_Bounds
(L_High
, R_High
))
5380 (Cond
, Length_E_Cond
(Exptyp
, T_Typ
, Indx
));
5389 -- Handle cases where we do not get a usable actual subtype that
5390 -- is constrained. This happens for example in the function call
5391 -- and explicit dereference cases. In these cases, we have to get
5392 -- the length or range from the expression itself, making sure we
5393 -- do not evaluate it more than once.
5395 -- Here Ck_Node is the original expression, or more properly the
5396 -- result of applying Duplicate_Expr to the original tree,
5397 -- forcing the result to be a name.
5401 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
5404 -- Build the condition for the explicit dereference case
5406 for Indx
in 1 .. Ndims
loop
5408 (Cond
, Length_N_Cond
(Ck_Node
, T_Typ
, Indx
));
5415 -- Construct the test and insert into the tree
5417 if Present
(Cond
) then
5419 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
5423 (Make_Raise_Constraint_Error
(Loc
,
5425 Reason
=> CE_Length_Check_Failed
));
5429 end Selected_Length_Checks
;
5431 ---------------------------
5432 -- Selected_Range_Checks --
5433 ---------------------------
5435 function Selected_Range_Checks
5437 Target_Typ
: Entity_Id
;
5438 Source_Typ
: Entity_Id
;
5439 Warn_Node
: Node_Id
) return Check_Result
5441 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
5444 Expr_Actual
: Node_Id
;
5446 Cond
: Node_Id
:= Empty
;
5447 Do_Access
: Boolean := False;
5448 Wnode
: Node_Id
:= Warn_Node
;
5449 Ret_Result
: Check_Result
:= (Empty
, Empty
);
5450 Num_Checks
: Integer := 0;
5452 procedure Add_Check
(N
: Node_Id
);
5453 -- Adds the action given to Ret_Result if N is non-Empty
5455 function Discrete_Range_Cond
5457 Typ
: Entity_Id
) return Node_Id
;
5458 -- Returns expression to compute:
5459 -- Low_Bound (Expr) < Typ'First
5461 -- High_Bound (Expr) > Typ'Last
5463 function Discrete_Expr_Cond
5465 Typ
: Entity_Id
) return Node_Id
;
5466 -- Returns expression to compute:
5471 function Get_E_First_Or_Last
5474 Nam
: Name_Id
) return Node_Id
;
5475 -- Returns expression to compute:
5476 -- E'First or E'Last
5478 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5479 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5480 -- Returns expression to compute:
5481 -- N'First or N'Last using Duplicate_Subexpr_No_Checks
5483 function Range_E_Cond
5484 (Exptyp
: Entity_Id
;
5488 -- Returns expression to compute:
5489 -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
5491 function Range_Equal_E_Cond
5492 (Exptyp
: Entity_Id
;
5494 Indx
: Nat
) return Node_Id
;
5495 -- Returns expression to compute:
5496 -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
5498 function Range_N_Cond
5501 Indx
: Nat
) return Node_Id
;
5502 -- Return expression to compute:
5503 -- Expr'First < Typ'First or else Expr'Last > Typ'Last
5509 procedure Add_Check
(N
: Node_Id
) is
5513 -- For now, ignore attempt to place more than 2 checks ???
5515 if Num_Checks
= 2 then
5519 pragma Assert
(Num_Checks
<= 1);
5520 Num_Checks
:= Num_Checks
+ 1;
5521 Ret_Result
(Num_Checks
) := N
;
5525 -------------------------
5526 -- Discrete_Expr_Cond --
5527 -------------------------
5529 function Discrete_Expr_Cond
5531 Typ
: Entity_Id
) return Node_Id
5539 Convert_To
(Base_Type
(Typ
),
5540 Duplicate_Subexpr_No_Checks
(Expr
)),
5542 Convert_To
(Base_Type
(Typ
),
5543 Get_E_First_Or_Last
(Typ
, 0, Name_First
))),
5548 Convert_To
(Base_Type
(Typ
),
5549 Duplicate_Subexpr_No_Checks
(Expr
)),
5553 Get_E_First_Or_Last
(Typ
, 0, Name_Last
))));
5554 end Discrete_Expr_Cond
;
5556 -------------------------
5557 -- Discrete_Range_Cond --
5558 -------------------------
5560 function Discrete_Range_Cond
5562 Typ
: Entity_Id
) return Node_Id
5564 LB
: Node_Id
:= Low_Bound
(Expr
);
5565 HB
: Node_Id
:= High_Bound
(Expr
);
5567 Left_Opnd
: Node_Id
;
5568 Right_Opnd
: Node_Id
;
5571 if Nkind
(LB
) = N_Identifier
5572 and then Ekind
(Entity
(LB
)) = E_Discriminant
then
5573 LB
:= New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
5576 if Nkind
(HB
) = N_Identifier
5577 and then Ekind
(Entity
(HB
)) = E_Discriminant
then
5578 HB
:= New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
5585 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(LB
)),
5589 (Base_Type
(Typ
), Get_E_First_Or_Last
(Typ
, 0, Name_First
)));
5591 if Base_Type
(Typ
) = Typ
then
5594 elsif Compile_Time_Known_Value
(High_Bound
(Scalar_Range
(Typ
)))
5596 Compile_Time_Known_Value
(High_Bound
(Scalar_Range
5599 if Is_Floating_Point_Type
(Typ
) then
5600 if Expr_Value_R
(High_Bound
(Scalar_Range
(Typ
))) =
5601 Expr_Value_R
(High_Bound
(Scalar_Range
(Base_Type
(Typ
))))
5607 if Expr_Value
(High_Bound
(Scalar_Range
(Typ
))) =
5608 Expr_Value
(High_Bound
(Scalar_Range
(Base_Type
(Typ
))))
5619 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(HB
)),
5624 Get_E_First_Or_Last
(Typ
, 0, Name_Last
)));
5626 return Make_Or_Else
(Loc
, Left_Opnd
, Right_Opnd
);
5627 end Discrete_Range_Cond
;
5629 -------------------------
5630 -- Get_E_First_Or_Last --
5631 -------------------------
5633 function Get_E_First_Or_Last
5636 Nam
: Name_Id
) return Node_Id
5644 if Is_Array_Type
(E
) then
5645 N
:= First_Index
(E
);
5647 for J
in 2 .. Indx
loop
5652 N
:= Scalar_Range
(E
);
5655 if Nkind
(N
) = N_Subtype_Indication
then
5656 LB
:= Low_Bound
(Range_Expression
(Constraint
(N
)));
5657 HB
:= High_Bound
(Range_Expression
(Constraint
(N
)));
5659 elsif Is_Entity_Name
(N
) then
5660 LB
:= Type_Low_Bound
(Etype
(N
));
5661 HB
:= Type_High_Bound
(Etype
(N
));
5664 LB
:= Low_Bound
(N
);
5665 HB
:= High_Bound
(N
);
5668 if Nam
= Name_First
then
5674 if Nkind
(Bound
) = N_Identifier
5675 and then Ekind
(Entity
(Bound
)) = E_Discriminant
5677 -- If this is a task discriminant, and we are the body, we must
5678 -- retrieve the corresponding body discriminal. This is another
5679 -- consequence of the early creation of discriminals, and the
5680 -- need to generate constraint checks before their declarations
5681 -- are made visible.
5683 if Is_Concurrent_Record_Type
(Scope
(Entity
(Bound
))) then
5685 Tsk
: constant Entity_Id
:=
5686 Corresponding_Concurrent_Type
5687 (Scope
(Entity
(Bound
)));
5691 if In_Open_Scopes
(Tsk
)
5692 and then Has_Completion
(Tsk
)
5694 -- Find discriminant of original task, and use its
5695 -- current discriminal, which is the renaming within
5698 Disc
:= First_Discriminant
(Tsk
);
5699 while Present
(Disc
) loop
5700 if Chars
(Disc
) = Chars
(Entity
(Bound
)) then
5701 Set_Scope
(Discriminal
(Disc
), Tsk
);
5702 return New_Occurrence_Of
(Discriminal
(Disc
), Loc
);
5705 Next_Discriminant
(Disc
);
5708 -- That loop should always succeed in finding a matching
5709 -- entry and returning. Fatal error if not.
5711 raise Program_Error
;
5715 New_Occurrence_Of
(Discriminal
(Entity
(Bound
)), Loc
);
5719 return New_Occurrence_Of
(Discriminal
(Entity
(Bound
)), Loc
);
5722 elsif Nkind
(Bound
) = N_Identifier
5723 and then Ekind
(Entity
(Bound
)) = E_In_Parameter
5724 and then not Inside_Init_Proc
5726 return Get_Discriminal
(E
, Bound
);
5728 elsif Nkind
(Bound
) = N_Integer_Literal
then
5729 return Make_Integer_Literal
(Loc
, Intval
(Bound
));
5732 return Duplicate_Subexpr_No_Checks
(Bound
);
5734 end Get_E_First_Or_Last
;
5740 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5743 Make_Attribute_Reference
(Loc
,
5744 Attribute_Name
=> Name_First
,
5746 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5747 Expressions
=> New_List
(
5748 Make_Integer_Literal
(Loc
, Indx
)));
5755 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5758 Make_Attribute_Reference
(Loc
,
5759 Attribute_Name
=> Name_Last
,
5761 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5762 Expressions
=> New_List
(
5763 Make_Integer_Literal
(Loc
, Indx
)));
5770 function Range_E_Cond
5771 (Exptyp
: Entity_Id
;
5773 Indx
: Nat
) return Node_Id
5780 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_First
),
5781 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5785 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_Last
),
5786 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5790 ------------------------
5791 -- Range_Equal_E_Cond --
5792 ------------------------
5794 function Range_Equal_E_Cond
5795 (Exptyp
: Entity_Id
;
5797 Indx
: Nat
) return Node_Id
5804 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_First
),
5805 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5808 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_Last
),
5809 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5810 end Range_Equal_E_Cond
;
5816 function Range_N_Cond
5819 Indx
: Nat
) return Node_Id
5826 Left_Opnd
=> Get_N_First
(Expr
, Indx
),
5827 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5831 Left_Opnd
=> Get_N_Last
(Expr
, Indx
),
5832 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5835 -- Start of processing for Selected_Range_Checks
5838 if not Expander_Active
then
5842 if Target_Typ
= Any_Type
5843 or else Target_Typ
= Any_Composite
5844 or else Raises_Constraint_Error
(Ck_Node
)
5853 T_Typ
:= Target_Typ
;
5855 if No
(Source_Typ
) then
5856 S_Typ
:= Etype
(Ck_Node
);
5858 S_Typ
:= Source_Typ
;
5861 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
5865 -- The order of evaluating T_Typ before S_Typ seems to be critical
5866 -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
5867 -- in, and since Node can be an N_Range node, it might be invalid.
5868 -- Should there be an assert check somewhere for taking the Etype of
5869 -- an N_Range node ???
5871 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
5872 S_Typ
:= Designated_Type
(S_Typ
);
5873 T_Typ
:= Designated_Type
(T_Typ
);
5876 -- A simple optimization
5878 if Nkind
(Ck_Node
) = N_Null
then
5883 -- For an N_Range Node, check for a null range and then if not
5884 -- null generate a range check action.
5886 if Nkind
(Ck_Node
) = N_Range
then
5888 -- There's no point in checking a range against itself
5890 if Ck_Node
= Scalar_Range
(T_Typ
) then
5895 T_LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
5896 T_HB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
5897 LB
: constant Node_Id
:= Low_Bound
(Ck_Node
);
5898 HB
: constant Node_Id
:= High_Bound
(Ck_Node
);
5899 Null_Range
: Boolean;
5901 Out_Of_Range_L
: Boolean;
5902 Out_Of_Range_H
: Boolean;
5905 -- Check for case where everything is static and we can
5906 -- do the check at compile time. This is skipped if we
5907 -- have an access type, since the access value may be null.
5909 -- ??? This code can be improved since you only need to know
5910 -- that the two respective bounds (LB & T_LB or HB & T_HB)
5911 -- are known at compile time to emit pertinent messages.
5913 if Compile_Time_Known_Value
(LB
)
5914 and then Compile_Time_Known_Value
(HB
)
5915 and then Compile_Time_Known_Value
(T_LB
)
5916 and then Compile_Time_Known_Value
(T_HB
)
5917 and then not Do_Access
5919 -- Floating-point case
5921 if Is_Floating_Point_Type
(S_Typ
) then
5922 Null_Range
:= Expr_Value_R
(HB
) < Expr_Value_R
(LB
);
5924 (Expr_Value_R
(LB
) < Expr_Value_R
(T_LB
))
5926 (Expr_Value_R
(LB
) > Expr_Value_R
(T_HB
));
5929 (Expr_Value_R
(HB
) > Expr_Value_R
(T_HB
))
5931 (Expr_Value_R
(HB
) < Expr_Value_R
(T_LB
));
5933 -- Fixed or discrete type case
5936 Null_Range
:= Expr_Value
(HB
) < Expr_Value
(LB
);
5938 (Expr_Value
(LB
) < Expr_Value
(T_LB
))
5940 (Expr_Value
(LB
) > Expr_Value
(T_HB
));
5943 (Expr_Value
(HB
) > Expr_Value
(T_HB
))
5945 (Expr_Value
(HB
) < Expr_Value
(T_LB
));
5948 if not Null_Range
then
5949 if Out_Of_Range_L
then
5950 if No
(Warn_Node
) then
5952 (Compile_Time_Constraint_Error
5953 (Low_Bound
(Ck_Node
),
5954 "static value out of range of}?", T_Typ
));
5958 (Compile_Time_Constraint_Error
5960 "static range out of bounds of}?", T_Typ
));
5964 if Out_Of_Range_H
then
5965 if No
(Warn_Node
) then
5967 (Compile_Time_Constraint_Error
5968 (High_Bound
(Ck_Node
),
5969 "static value out of range of}?", T_Typ
));
5973 (Compile_Time_Constraint_Error
5975 "static range out of bounds of}?", T_Typ
));
5983 LB
: Node_Id
:= Low_Bound
(Ck_Node
);
5984 HB
: Node_Id
:= High_Bound
(Ck_Node
);
5988 -- If either bound is a discriminant and we are within
5989 -- the record declaration, it is a use of the discriminant
5990 -- in a constraint of a component, and nothing can be
5991 -- checked here. The check will be emitted within the
5992 -- init proc. Before then, the discriminal has no real
5995 if Nkind
(LB
) = N_Identifier
5996 and then Ekind
(Entity
(LB
)) = E_Discriminant
5998 if Current_Scope
= Scope
(Entity
(LB
)) then
6002 New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
6006 if Nkind
(HB
) = N_Identifier
6007 and then Ekind
(Entity
(HB
)) = E_Discriminant
6009 if Current_Scope
= Scope
(Entity
(HB
)) then
6013 New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
6017 Cond
:= Discrete_Range_Cond
(Ck_Node
, T_Typ
);
6018 Set_Paren_Count
(Cond
, 1);
6024 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(HB
),
6025 Right_Opnd
=> Duplicate_Subexpr_No_Checks
(LB
)),
6026 Right_Opnd
=> Cond
);
6032 elsif Is_Scalar_Type
(S_Typ
) then
6034 -- This somewhat duplicates what Apply_Scalar_Range_Check does,
6035 -- except the above simply sets a flag in the node and lets
6036 -- gigi generate the check base on the Etype of the expression.
6037 -- Sometimes, however we want to do a dynamic check against an
6038 -- arbitrary target type, so we do that here.
6040 if Ekind
(Base_Type
(S_Typ
)) /= Ekind
(Base_Type
(T_Typ
)) then
6041 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6043 -- For literals, we can tell if the constraint error will be
6044 -- raised at compile time, so we never need a dynamic check, but
6045 -- if the exception will be raised, then post the usual warning,
6046 -- and replace the literal with a raise constraint error
6047 -- expression. As usual, skip this for access types
6049 elsif Compile_Time_Known_Value
(Ck_Node
)
6050 and then not Do_Access
6053 LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
6054 UB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
6056 Out_Of_Range
: Boolean;
6057 Static_Bounds
: constant Boolean :=
6058 Compile_Time_Known_Value
(LB
)
6059 and Compile_Time_Known_Value
(UB
);
6062 -- Following range tests should use Sem_Eval routine ???
6064 if Static_Bounds
then
6065 if Is_Floating_Point_Type
(S_Typ
) then
6067 (Expr_Value_R
(Ck_Node
) < Expr_Value_R
(LB
))
6069 (Expr_Value_R
(Ck_Node
) > Expr_Value_R
(UB
));
6071 else -- fixed or discrete type
6073 Expr_Value
(Ck_Node
) < Expr_Value
(LB
)
6075 Expr_Value
(Ck_Node
) > Expr_Value
(UB
);
6078 -- Bounds of the type are static and the literal is
6079 -- out of range so make a warning message.
6081 if Out_Of_Range
then
6082 if No
(Warn_Node
) then
6084 (Compile_Time_Constraint_Error
6086 "static value out of range of}?", T_Typ
));
6090 (Compile_Time_Constraint_Error
6092 "static value out of range of}?", T_Typ
));
6097 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6101 -- Here for the case of a non-static expression, we need a runtime
6102 -- check unless the source type range is guaranteed to be in the
6103 -- range of the target type.
6106 if not In_Subrange_Of
(S_Typ
, T_Typ
) then
6107 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6112 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
6113 if Is_Constrained
(T_Typ
) then
6115 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
6116 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
6118 if Is_Access_Type
(Exptyp
) then
6119 Exptyp
:= Designated_Type
(Exptyp
);
6122 -- String_Literal case. This needs to be handled specially be-
6123 -- cause no index types are available for string literals. The
6124 -- condition is simply:
6126 -- T_Typ'Length = string-literal-length
6128 if Nkind
(Expr_Actual
) = N_String_Literal
then
6131 -- General array case. Here we have a usable actual subtype for
6132 -- the expression, and the condition is built from the two types
6134 -- T_Typ'First < Exptyp'First or else
6135 -- T_Typ'Last > Exptyp'Last or else
6136 -- T_Typ'First(1) < Exptyp'First(1) or else
6137 -- T_Typ'Last(1) > Exptyp'Last(1) or else
6140 elsif Is_Constrained
(Exptyp
) then
6142 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
6152 L_Index
:= First_Index
(T_Typ
);
6153 R_Index
:= First_Index
(Exptyp
);
6155 for Indx
in 1 .. Ndims
loop
6156 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
6158 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
6160 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
6161 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
6163 -- Deal with compile time length check. Note that we
6164 -- skip this in the access case, because the access
6165 -- value may be null, so we cannot know statically.
6168 Subtypes_Statically_Match
6169 (Etype
(L_Index
), Etype
(R_Index
))
6171 -- If the target type is constrained then we
6172 -- have to check for exact equality of bounds
6173 -- (required for qualified expressions).
6175 if Is_Constrained
(T_Typ
) then
6178 Range_Equal_E_Cond
(Exptyp
, T_Typ
, Indx
));
6182 (Cond
, Range_E_Cond
(Exptyp
, T_Typ
, Indx
));
6193 -- Handle cases where we do not get a usable actual subtype that
6194 -- is constrained. This happens for example in the function call
6195 -- and explicit dereference cases. In these cases, we have to get
6196 -- the length or range from the expression itself, making sure we
6197 -- do not evaluate it more than once.
6199 -- Here Ck_Node is the original expression, or more properly the
6200 -- result of applying Duplicate_Expr to the original tree,
6201 -- forcing the result to be a name.
6205 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
6208 -- Build the condition for the explicit dereference case
6210 for Indx
in 1 .. Ndims
loop
6212 (Cond
, Range_N_Cond
(Ck_Node
, T_Typ
, Indx
));
6219 -- Generate an Action to check that the bounds of the
6220 -- source value are within the constraints imposed by the
6221 -- target type for a conversion to an unconstrained type.
6224 if Nkind
(Parent
(Ck_Node
)) = N_Type_Conversion
then
6226 Opnd_Index
: Node_Id
;
6227 Targ_Index
: Node_Id
;
6231 := First_Index
(Get_Actual_Subtype
(Ck_Node
));
6232 Targ_Index
:= First_Index
(T_Typ
);
6234 while Opnd_Index
/= Empty
loop
6235 if Nkind
(Opnd_Index
) = N_Range
then
6237 (Low_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6240 (High_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6244 -- If null range, no check needed.
6246 Compile_Time_Known_Value
(High_Bound
(Opnd_Index
))
6248 Compile_Time_Known_Value
(Low_Bound
(Opnd_Index
))
6250 Expr_Value
(High_Bound
(Opnd_Index
)) <
6251 Expr_Value
(Low_Bound
(Opnd_Index
))
6255 elsif Is_Out_Of_Range
6256 (Low_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6259 (High_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6262 (Compile_Time_Constraint_Error
6263 (Wnode
, "value out of range of}?", T_Typ
));
6269 (Opnd_Index
, Etype
(Targ_Index
)));
6273 Next_Index
(Opnd_Index
);
6274 Next_Index
(Targ_Index
);
6281 -- Construct the test and insert into the tree
6283 if Present
(Cond
) then
6285 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
6289 (Make_Raise_Constraint_Error
(Loc
,
6291 Reason
=> CE_Range_Check_Failed
));
6295 end Selected_Range_Checks
;
6297 -------------------------------
6298 -- Storage_Checks_Suppressed --
6299 -------------------------------
6301 function Storage_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6303 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
6304 return Is_Check_Suppressed
(E
, Storage_Check
);
6306 return Scope_Suppress
(Storage_Check
);
6308 end Storage_Checks_Suppressed
;
6310 ---------------------------
6311 -- Tag_Checks_Suppressed --
6312 ---------------------------
6314 function Tag_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6317 if Kill_Tag_Checks
(E
) then
6319 elsif Checks_May_Be_Suppressed
(E
) then
6320 return Is_Check_Suppressed
(E
, Tag_Check
);
6324 return Scope_Suppress
(Tag_Check
);
6325 end Tag_Checks_Suppressed
;