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
);
471 Typ
: constant Entity_Id
:= Etype
(E
);
475 Alignment_Required
: constant Boolean := Maximum_Alignment
> 1;
476 -- Constant to show whether target requires alignment checks
479 -- See if check needed. Note that we never need a check if the
480 -- maximum alignment is one, since the check will always succeed
483 or else not Check_Address_Alignment
(AC
)
484 or else not Alignment_Required
490 Expr
:= Expression
(AC
);
492 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
then
493 Expr
:= Expression
(Expr
);
495 elsif Nkind
(Expr
) = N_Function_Call
496 and then Is_Entity_Name
(Name
(Expr
))
497 and then Is_RTE
(Entity
(Name
(Expr
)), RE_To_Address
)
499 Expr
:= First
(Parameter_Associations
(Expr
));
501 if Nkind
(Expr
) = N_Parameter_Association
then
502 Expr
:= Explicit_Actual_Parameter
(Expr
);
506 -- Here Expr is the address value. See if we know that the
507 -- value is unacceptable at compile time.
509 if Compile_Time_Known_Value
(Expr
)
510 and then (Known_Alignment
(E
) or else Known_Alignment
(Typ
))
513 AL
: Uint
:= Alignment
(Typ
);
516 -- The object alignment might be more restrictive than the
519 if Known_Alignment
(E
) then
523 if Expr_Value
(Expr
) mod AL
/= 0 then
525 Make_Raise_Program_Error
(Loc
,
526 Reason
=> PE_Misaligned_Address_Value
));
528 ("?specified address for& not " &
529 "consistent with alignment ('R'M 13.3(27))", Expr
, E
);
533 -- Here we do not know if the value is acceptable, generate
534 -- code to raise PE if alignment is inappropriate.
537 -- Skip generation of this code if we don't want elab code
539 if not Restriction_Active
(No_Elaboration_Code
) then
540 Insert_After_And_Analyze
(N
,
541 Make_Raise_Program_Error
(Loc
,
548 (RTE
(RE_Integer_Address
),
549 Duplicate_Subexpr_No_Checks
(Expr
)),
551 Make_Attribute_Reference
(Loc
,
552 Prefix
=> New_Occurrence_Of
(E
, Loc
),
553 Attribute_Name
=> Name_Alignment
)),
554 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
555 Reason
=> PE_Misaligned_Address_Value
),
556 Suppress
=> All_Checks
);
563 when RE_Not_Available
=>
565 end Apply_Alignment_Check
;
567 -------------------------------------
568 -- Apply_Arithmetic_Overflow_Check --
569 -------------------------------------
571 -- This routine is called only if the type is an integer type, and
572 -- a software arithmetic overflow check must be performed for op
573 -- (add, subtract, multiply). The check is performed only if
574 -- Software_Overflow_Checking is enabled and Do_Overflow_Check
575 -- is set. In this case we expand the operation into a more complex
576 -- sequence of tests that ensures that overflow is properly caught.
578 procedure Apply_Arithmetic_Overflow_Check
(N
: Node_Id
) is
579 Loc
: constant Source_Ptr
:= Sloc
(N
);
580 Typ
: constant Entity_Id
:= Etype
(N
);
581 Rtyp
: constant Entity_Id
:= Root_Type
(Typ
);
582 Siz
: constant Int
:= UI_To_Int
(Esize
(Rtyp
));
583 Dsiz
: constant Int
:= Siz
* 2;
590 -- Skip this if overflow checks are done in back end, or the overflow
591 -- flag is not set anyway, or we are not doing code expansion.
593 if Backend_Overflow_Checks_On_Target
594 or else not Do_Overflow_Check
(N
)
595 or else not Expander_Active
600 -- Otherwise, we generate the full general code for front end overflow
601 -- detection, which works by doing arithmetic in a larger type:
607 -- Typ (Checktyp (x) op Checktyp (y));
609 -- where Typ is the type of the original expression, and Checktyp is
610 -- an integer type of sufficient length to hold the largest possible
613 -- In the case where check type exceeds the size of Long_Long_Integer,
614 -- we use a different approach, expanding to:
616 -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y)))
618 -- where xxx is Add, Multiply or Subtract as appropriate
620 -- Find check type if one exists
622 if Dsiz
<= Standard_Integer_Size
then
623 Ctyp
:= Standard_Integer
;
625 elsif Dsiz
<= Standard_Long_Long_Integer_Size
then
626 Ctyp
:= Standard_Long_Long_Integer
;
628 -- No check type exists, use runtime call
631 if Nkind
(N
) = N_Op_Add
then
632 Cent
:= RE_Add_With_Ovflo_Check
;
634 elsif Nkind
(N
) = N_Op_Multiply
then
635 Cent
:= RE_Multiply_With_Ovflo_Check
;
638 pragma Assert
(Nkind
(N
) = N_Op_Subtract
);
639 Cent
:= RE_Subtract_With_Ovflo_Check
;
644 Make_Function_Call
(Loc
,
645 Name
=> New_Reference_To
(RTE
(Cent
), Loc
),
646 Parameter_Associations
=> New_List
(
647 OK_Convert_To
(RTE
(RE_Integer_64
), Left_Opnd
(N
)),
648 OK_Convert_To
(RTE
(RE_Integer_64
), Right_Opnd
(N
))))));
650 Analyze_And_Resolve
(N
, Typ
);
654 -- If we fall through, we have the case where we do the arithmetic in
655 -- the next higher type and get the check by conversion. In these cases
656 -- Ctyp is set to the type to be used as the check type.
658 Opnod
:= Relocate_Node
(N
);
660 Opnd
:= OK_Convert_To
(Ctyp
, Left_Opnd
(Opnod
));
663 Set_Etype
(Opnd
, Ctyp
);
664 Set_Analyzed
(Opnd
, True);
665 Set_Left_Opnd
(Opnod
, Opnd
);
667 Opnd
:= OK_Convert_To
(Ctyp
, Right_Opnd
(Opnod
));
670 Set_Etype
(Opnd
, Ctyp
);
671 Set_Analyzed
(Opnd
, True);
672 Set_Right_Opnd
(Opnod
, Opnd
);
674 -- The type of the operation changes to the base type of the check
675 -- type, and we reset the overflow check indication, since clearly
676 -- no overflow is possible now that we are using a double length
677 -- type. We also set the Analyzed flag to avoid a recursive attempt
678 -- to expand the node.
680 Set_Etype
(Opnod
, Base_Type
(Ctyp
));
681 Set_Do_Overflow_Check
(Opnod
, False);
682 Set_Analyzed
(Opnod
, True);
684 -- Now build the outer conversion
686 Opnd
:= OK_Convert_To
(Typ
, Opnod
);
688 Set_Etype
(Opnd
, Typ
);
690 -- In the discrete type case, we directly generate the range check
691 -- for the outer operand. This range check will implement the required
694 if Is_Discrete_Type
(Typ
) then
696 Generate_Range_Check
(Expression
(N
), Typ
, CE_Overflow_Check_Failed
);
698 -- For other types, we enable overflow checking on the conversion,
699 -- after setting the node as analyzed to prevent recursive attempts
700 -- to expand the conversion node.
703 Set_Analyzed
(Opnd
, True);
704 Enable_Overflow_Check
(Opnd
);
709 when RE_Not_Available
=>
711 end Apply_Arithmetic_Overflow_Check
;
713 ----------------------------
714 -- Apply_Array_Size_Check --
715 ----------------------------
717 -- Note: Really of course this entre check should be in the backend,
718 -- and perhaps this is not quite the right value, but it is good
719 -- enough to catch the normal cases (and the relevant ACVC tests!)
721 -- The situation is as follows. In GNAT 3 (GCC 2.x), the size in bits
722 -- is computed in 32 bits without an overflow check. That's a real
723 -- problem for Ada. So what we do in GNAT 3 is to approximate the
724 -- size of an array by manually multiplying the element size by the
725 -- number of elements, and comparing that against the allowed limits.
727 -- In GNAT 5, the size in byte is still computed in 32 bits without
728 -- an overflow check in the dynamic case, but the size in bits is
729 -- computed in 64 bits. We assume that's good enough, so we use the
730 -- size in bits for the test.
732 procedure Apply_Array_Size_Check
(N
: Node_Id
; Typ
: Entity_Id
) is
733 Loc
: constant Source_Ptr
:= Sloc
(N
);
734 Ctyp
: constant Entity_Id
:= Component_Type
(Typ
);
735 Ent
: constant Entity_Id
:= Defining_Identifier
(N
);
747 Static
: Boolean := True;
748 -- Set false if any index subtye bound is non-static
750 Umark
: constant Uintp
.Save_Mark
:= Uintp
.Mark
;
751 -- We can throw away all the Uint computations here, since they are
752 -- done only to generate boolean test results.
755 -- Size to check against
757 function Is_Address_Or_Import
(Decl
: Node_Id
) return Boolean;
758 -- Determines if Decl is an address clause or Import/Interface pragma
759 -- that references the defining identifier of the current declaration.
761 --------------------------
762 -- Is_Address_Or_Import --
763 --------------------------
765 function Is_Address_Or_Import
(Decl
: Node_Id
) return Boolean is
767 if Nkind
(Decl
) = N_At_Clause
then
768 return Chars
(Identifier
(Decl
)) = Chars
(Ent
);
770 elsif Nkind
(Decl
) = N_Attribute_Definition_Clause
then
772 Chars
(Decl
) = Name_Address
774 Nkind
(Name
(Decl
)) = N_Identifier
776 Chars
(Name
(Decl
)) = Chars
(Ent
);
778 elsif Nkind
(Decl
) = N_Pragma
then
779 if (Chars
(Decl
) = Name_Import
781 Chars
(Decl
) = Name_Interface
)
782 and then Present
(Pragma_Argument_Associations
(Decl
))
785 F
: constant Node_Id
:=
786 First
(Pragma_Argument_Associations
(Decl
));
794 Nkind
(Expression
(Next
(F
))) = N_Identifier
796 Chars
(Expression
(Next
(F
))) = Chars
(Ent
);
806 end Is_Address_Or_Import
;
808 -- Start of processing for Apply_Array_Size_Check
811 -- No need for a check if not expanding
813 if not Expander_Active
then
817 -- No need for a check if checks are suppressed
819 if Storage_Checks_Suppressed
(Typ
) then
823 -- It is pointless to insert this check inside an init proc, because
824 -- that's too late, we have already built the object to be the right
825 -- size, and if it's too large, too bad!
827 if Inside_Init_Proc
then
831 -- Look head for pragma interface/import or address clause applying
832 -- to this entity. If found, we suppress the check entirely. For now
833 -- we only look ahead 20 declarations to stop this becoming too slow
834 -- Note that eventually this whole routine gets moved to gigi.
837 for Ctr
in 1 .. 20 loop
841 if Is_Address_Or_Import
(Decl
) then
848 if Opt
.GCC_Version
= 3 then
850 -- No problem if size is known at compile time (even if the front
851 -- end does not know it) because the back end does do overflow
852 -- checking on the size in bytes if it is compile time known.
854 if Size_Known_At_Compile_Time
(Typ
) then
859 -- Following code is temporarily deleted, since GCC 3 is returning
860 -- zero for size in bits of large dynamic arrays. ???
862 -- -- Otherwise we check for the size in bits exceeding 2**31-1 * 8.
863 -- -- This is the case in which we could end up with problems from
864 -- -- an unnoticed overflow in computing the size in bytes
866 -- Check_Siz := (Uint_2 ** 31 - Uint_1) * Uint_8;
869 -- Make_Attribute_Reference (Loc,
870 -- Prefix => New_Occurrence_Of (Typ, Loc),
871 -- Attribute_Name => Name_Size);
873 -- GCC 2 case (for now this is for GCC 3 dynamic case as well)
876 -- First step is to calculate the maximum number of elements. For
877 -- this calculation, we use the actual size of the subtype if it is
878 -- static, and if a bound of a subtype is non-static, we go to the
879 -- bound of the base type.
882 Indx
:= First_Index
(Typ
);
883 while Present
(Indx
) loop
884 Xtyp
:= Etype
(Indx
);
885 Lo
:= Type_Low_Bound
(Xtyp
);
886 Hi
:= Type_High_Bound
(Xtyp
);
888 -- If any bound raises constraint error, we will never get this
889 -- far, so there is no need to generate any kind of check.
891 if Raises_Constraint_Error
(Lo
)
893 Raises_Constraint_Error
(Hi
)
895 Uintp
.Release
(Umark
);
899 -- Otherwise get bounds values
901 if Is_Static_Expression
(Lo
) then
902 Lob
:= Expr_Value
(Lo
);
904 Lob
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Xtyp
)));
908 if Is_Static_Expression
(Hi
) then
909 Hib
:= Expr_Value
(Hi
);
911 Hib
:= Expr_Value
(Type_High_Bound
(Base_Type
(Xtyp
)));
915 Siz
:= Siz
* UI_Max
(Hib
- Lob
+ 1, Uint_0
);
919 -- Compute the limit against which we want to check. For subprograms,
920 -- where the array will go on the stack, we use 8*2**24, which (in
921 -- bits) is the size of a 16 megabyte array.
923 if Is_Subprogram
(Scope
(Ent
)) then
924 Check_Siz
:= Uint_2
** 27;
926 Check_Siz
:= Uint_2
** 31;
929 -- If we have all static bounds and Siz is too large, then we know
930 -- we know we have a storage error right now, so generate message
932 if Static
and then Siz
>= Check_Siz
then
934 Make_Raise_Storage_Error
(Loc
,
935 Reason
=> SE_Object_Too_Large
));
936 Error_Msg_N
("?Storage_Error will be raised at run-time", N
);
937 Uintp
.Release
(Umark
);
941 -- Case of component size known at compile time. If the array
942 -- size is definitely in range, then we do not need a check.
944 if Known_Esize
(Ctyp
)
945 and then Siz
* Esize
(Ctyp
) < Check_Siz
947 Uintp
.Release
(Umark
);
951 -- Here if a dynamic check is required
953 -- What we do is to build an expression for the size of the array,
954 -- which is computed as the 'Size of the array component, times
955 -- the size of each dimension.
957 Uintp
.Release
(Umark
);
960 Make_Attribute_Reference
(Loc
,
961 Prefix
=> New_Occurrence_Of
(Ctyp
, Loc
),
962 Attribute_Name
=> Name_Size
);
964 Indx
:= First_Index
(Typ
);
965 for J
in 1 .. Number_Dimensions
(Typ
) loop
966 if Sloc
(Etype
(Indx
)) = Sloc
(N
) then
967 Ensure_Defined
(Etype
(Indx
), N
);
971 Make_Op_Multiply
(Loc
,
974 Make_Attribute_Reference
(Loc
,
975 Prefix
=> New_Occurrence_Of
(Typ
, Loc
),
976 Attribute_Name
=> Name_Length
,
977 Expressions
=> New_List
(
978 Make_Integer_Literal
(Loc
, J
))));
983 -- Common code to actually emit the check
986 Make_Raise_Storage_Error
(Loc
,
991 Make_Integer_Literal
(Loc
,
992 Intval
=> Check_Siz
)),
993 Reason
=> SE_Object_Too_Large
);
995 Set_Size_Check_Code
(Defining_Identifier
(N
), Code
);
996 Insert_Action
(N
, Code
, Suppress
=> All_Checks
);
997 end Apply_Array_Size_Check
;
999 ----------------------------
1000 -- Apply_Constraint_Check --
1001 ----------------------------
1003 procedure Apply_Constraint_Check
1006 No_Sliding
: Boolean := False)
1008 Desig_Typ
: Entity_Id
;
1011 if Inside_A_Generic
then
1014 elsif Is_Scalar_Type
(Typ
) then
1015 Apply_Scalar_Range_Check
(N
, Typ
);
1017 elsif Is_Array_Type
(Typ
) then
1019 -- A useful optimization: an aggregate with only an Others clause
1020 -- always has the right bounds.
1022 if Nkind
(N
) = N_Aggregate
1023 and then No
(Expressions
(N
))
1025 (First
(Choices
(First
(Component_Associations
(N
)))))
1031 if Is_Constrained
(Typ
) then
1032 Apply_Length_Check
(N
, Typ
);
1035 Apply_Range_Check
(N
, Typ
);
1038 Apply_Range_Check
(N
, Typ
);
1041 elsif (Is_Record_Type
(Typ
)
1042 or else Is_Private_Type
(Typ
))
1043 and then Has_Discriminants
(Base_Type
(Typ
))
1044 and then Is_Constrained
(Typ
)
1046 Apply_Discriminant_Check
(N
, Typ
);
1048 elsif Is_Access_Type
(Typ
) then
1050 Desig_Typ
:= Designated_Type
(Typ
);
1052 -- No checks necessary if expression statically null
1054 if Nkind
(N
) = N_Null
then
1057 -- No sliding possible on access to arrays
1059 elsif Is_Array_Type
(Desig_Typ
) then
1060 if Is_Constrained
(Desig_Typ
) then
1061 Apply_Length_Check
(N
, Typ
);
1064 Apply_Range_Check
(N
, Typ
);
1066 elsif Has_Discriminants
(Base_Type
(Desig_Typ
))
1067 and then Is_Constrained
(Desig_Typ
)
1069 Apply_Discriminant_Check
(N
, Typ
);
1072 if Can_Never_Be_Null
(Typ
)
1073 and then not Can_Never_Be_Null
(Etype
(N
))
1075 Install_Null_Excluding_Check
(N
);
1078 end Apply_Constraint_Check
;
1080 ------------------------------
1081 -- Apply_Discriminant_Check --
1082 ------------------------------
1084 procedure Apply_Discriminant_Check
1087 Lhs
: Node_Id
:= Empty
)
1089 Loc
: constant Source_Ptr
:= Sloc
(N
);
1090 Do_Access
: constant Boolean := Is_Access_Type
(Typ
);
1091 S_Typ
: Entity_Id
:= Etype
(N
);
1095 function Is_Aliased_Unconstrained_Component
return Boolean;
1096 -- It is possible for an aliased component to have a nominal
1097 -- unconstrained subtype (through instantiation). If this is a
1098 -- discriminated component assigned in the expansion of an aggregate
1099 -- in an initialization, the check must be suppressed. This unusual
1100 -- situation requires a predicate of its own (see 7503-008).
1102 ----------------------------------------
1103 -- Is_Aliased_Unconstrained_Component --
1104 ----------------------------------------
1106 function Is_Aliased_Unconstrained_Component
return Boolean is
1111 if Nkind
(Lhs
) /= N_Selected_Component
then
1114 Comp
:= Entity
(Selector_Name
(Lhs
));
1115 Pref
:= Prefix
(Lhs
);
1118 if Ekind
(Comp
) /= E_Component
1119 or else not Is_Aliased
(Comp
)
1124 return not Comes_From_Source
(Pref
)
1125 and then In_Instance
1126 and then not Is_Constrained
(Etype
(Comp
));
1127 end Is_Aliased_Unconstrained_Component
;
1129 -- Start of processing for Apply_Discriminant_Check
1133 T_Typ
:= Designated_Type
(Typ
);
1138 -- Nothing to do if discriminant checks are suppressed or else no code
1139 -- is to be generated
1141 if not Expander_Active
1142 or else Discriminant_Checks_Suppressed
(T_Typ
)
1147 -- No discriminant checks necessary for access when expression
1148 -- is statically Null. This is not only an optimization, this is
1149 -- fundamental because otherwise discriminant checks may be generated
1150 -- in init procs for types containing an access to a non-frozen yet
1151 -- record, causing a deadly forward reference.
1153 -- Also, if the expression is of an access type whose designated
1154 -- type is incomplete, then the access value must be null and
1155 -- we suppress the check.
1157 if Nkind
(N
) = N_Null
then
1160 elsif Is_Access_Type
(S_Typ
) then
1161 S_Typ
:= Designated_Type
(S_Typ
);
1163 if Ekind
(S_Typ
) = E_Incomplete_Type
then
1168 -- If an assignment target is present, then we need to generate
1169 -- the actual subtype if the target is a parameter or aliased
1170 -- object with an unconstrained nominal subtype.
1173 and then (Present
(Param_Entity
(Lhs
))
1174 or else (not Is_Constrained
(T_Typ
)
1175 and then Is_Aliased_View
(Lhs
)
1176 and then not Is_Aliased_Unconstrained_Component
))
1178 T_Typ
:= Get_Actual_Subtype
(Lhs
);
1181 -- Nothing to do if the type is unconstrained (this is the case
1182 -- where the actual subtype in the RM sense of N is unconstrained
1183 -- and no check is required).
1185 if not Is_Constrained
(T_Typ
) then
1189 -- Nothing to do if the type is an Unchecked_Union
1191 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
1195 -- Suppress checks if the subtypes are the same.
1196 -- the check must be preserved in an assignment to a formal, because
1197 -- the constraint is given by the actual.
1199 if Nkind
(Original_Node
(N
)) /= N_Allocator
1201 or else not Is_Entity_Name
(Lhs
)
1202 or else No
(Param_Entity
(Lhs
)))
1205 or else (Do_Access
and then Designated_Type
(Typ
) = S_Typ
))
1206 and then not Is_Aliased_View
(Lhs
)
1211 -- We can also eliminate checks on allocators with a subtype mark
1212 -- that coincides with the context type. The context type may be a
1213 -- subtype without a constraint (common case, a generic actual).
1215 elsif Nkind
(Original_Node
(N
)) = N_Allocator
1216 and then Is_Entity_Name
(Expression
(Original_Node
(N
)))
1219 Alloc_Typ
: constant Entity_Id
:=
1220 Entity
(Expression
(Original_Node
(N
)));
1223 if Alloc_Typ
= T_Typ
1224 or else (Nkind
(Parent
(T_Typ
)) = N_Subtype_Declaration
1225 and then Is_Entity_Name
(
1226 Subtype_Indication
(Parent
(T_Typ
)))
1227 and then Alloc_Typ
= Base_Type
(T_Typ
))
1235 -- See if we have a case where the types are both constrained, and
1236 -- all the constraints are constants. In this case, we can do the
1237 -- check successfully at compile time.
1239 -- We skip this check for the case where the node is a rewritten`
1240 -- allocator, because it already carries the context subtype, and
1241 -- extracting the discriminants from the aggregate is messy.
1243 if Is_Constrained
(S_Typ
)
1244 and then Nkind
(Original_Node
(N
)) /= N_Allocator
1254 -- S_Typ may not have discriminants in the case where it is a
1255 -- private type completed by a default discriminated type. In
1256 -- that case, we need to get the constraints from the
1257 -- underlying_type. If the underlying type is unconstrained (i.e.
1258 -- has no default discriminants) no check is needed.
1260 if Has_Discriminants
(S_Typ
) then
1261 Discr
:= First_Discriminant
(S_Typ
);
1262 DconS
:= First_Elmt
(Discriminant_Constraint
(S_Typ
));
1265 Discr
:= First_Discriminant
(Underlying_Type
(S_Typ
));
1268 (Discriminant_Constraint
(Underlying_Type
(S_Typ
)));
1274 -- A further optimization: if T_Typ is derived from S_Typ
1275 -- without imposing a constraint, no check is needed.
1277 if Nkind
(Original_Node
(Parent
(T_Typ
))) =
1278 N_Full_Type_Declaration
1281 Type_Def
: constant Node_Id
:=
1283 (Original_Node
(Parent
(T_Typ
)));
1285 if Nkind
(Type_Def
) = N_Derived_Type_Definition
1286 and then Is_Entity_Name
(Subtype_Indication
(Type_Def
))
1287 and then Entity
(Subtype_Indication
(Type_Def
)) = S_Typ
1295 DconT
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
1297 while Present
(Discr
) loop
1298 ItemS
:= Node
(DconS
);
1299 ItemT
:= Node
(DconT
);
1302 not Is_OK_Static_Expression
(ItemS
)
1304 not Is_OK_Static_Expression
(ItemT
);
1306 if Expr_Value
(ItemS
) /= Expr_Value
(ItemT
) then
1307 if Do_Access
then -- needs run-time check.
1310 Apply_Compile_Time_Constraint_Error
1311 (N
, "incorrect value for discriminant&?",
1312 CE_Discriminant_Check_Failed
, Ent
=> Discr
);
1319 Next_Discriminant
(Discr
);
1328 -- Here we need a discriminant check. First build the expression
1329 -- for the comparisons of the discriminants:
1331 -- (n.disc1 /= typ.disc1) or else
1332 -- (n.disc2 /= typ.disc2) or else
1334 -- (n.discn /= typ.discn)
1336 Cond
:= Build_Discriminant_Checks
(N
, T_Typ
);
1338 -- If Lhs is set and is a parameter, then the condition is
1339 -- guarded by: lhs'constrained and then (condition built above)
1341 if Present
(Param_Entity
(Lhs
)) then
1345 Make_Attribute_Reference
(Loc
,
1346 Prefix
=> New_Occurrence_Of
(Param_Entity
(Lhs
), Loc
),
1347 Attribute_Name
=> Name_Constrained
),
1348 Right_Opnd
=> Cond
);
1352 Cond
:= Guard_Access
(Cond
, Loc
, N
);
1356 Make_Raise_Constraint_Error
(Loc
,
1358 Reason
=> CE_Discriminant_Check_Failed
));
1359 end Apply_Discriminant_Check
;
1361 ------------------------
1362 -- Apply_Divide_Check --
1363 ------------------------
1365 procedure Apply_Divide_Check
(N
: Node_Id
) is
1366 Loc
: constant Source_Ptr
:= Sloc
(N
);
1367 Typ
: constant Entity_Id
:= Etype
(N
);
1368 Left
: constant Node_Id
:= Left_Opnd
(N
);
1369 Right
: constant Node_Id
:= Right_Opnd
(N
);
1381 and not Backend_Divide_Checks_On_Target
1383 Determine_Range
(Right
, ROK
, Rlo
, Rhi
);
1385 -- See if division by zero possible, and if so generate test. This
1386 -- part of the test is not controlled by the -gnato switch.
1388 if Do_Division_Check
(N
) then
1389 if (not ROK
) or else (Rlo
<= 0 and then 0 <= Rhi
) then
1391 Make_Raise_Constraint_Error
(Loc
,
1394 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(Right
),
1395 Right_Opnd
=> Make_Integer_Literal
(Loc
, 0)),
1396 Reason
=> CE_Divide_By_Zero
));
1400 -- Test for extremely annoying case of xxx'First divided by -1
1402 if Do_Overflow_Check
(N
) then
1404 if Nkind
(N
) = N_Op_Divide
1405 and then Is_Signed_Integer_Type
(Typ
)
1407 Determine_Range
(Left
, LOK
, Llo
, Lhi
);
1408 LLB
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
1410 if ((not ROK
) or else (Rlo
<= (-1) and then (-1) <= Rhi
))
1412 ((not LOK
) or else (Llo
= LLB
))
1415 Make_Raise_Constraint_Error
(Loc
,
1421 Duplicate_Subexpr_Move_Checks
(Left
),
1422 Right_Opnd
=> Make_Integer_Literal
(Loc
, LLB
)),
1426 Duplicate_Subexpr
(Right
),
1428 Make_Integer_Literal
(Loc
, -1))),
1429 Reason
=> CE_Overflow_Check_Failed
));
1434 end Apply_Divide_Check
;
1436 ----------------------------------
1437 -- Apply_Float_Conversion_Check --
1438 ----------------------------------
1440 -- Let F and I be the source and target types of the conversion.
1441 -- The Ada standard specifies that a floating-point value X is rounded
1442 -- to the nearest integer, with halfway cases being rounded away from
1443 -- zero. The rounded value of X is checked against I'Range.
1445 -- The catch in the above paragraph is that there is no good way
1446 -- to know whether the round-to-integer operation resulted in
1447 -- overflow. A remedy is to perform a range check in the floating-point
1448 -- domain instead, however:
1449 -- (1) The bounds may not be known at compile time
1450 -- (2) The check must take into account possible rounding.
1451 -- (3) The range of type I may not be exactly representable in F.
1452 -- (4) The end-points I'First - 0.5 and I'Last + 0.5 may or may
1453 -- not be in range, depending on the sign of I'First and I'Last.
1454 -- (5) X may be a NaN, which will fail any comparison
1456 -- The following steps take care of these issues converting X:
1457 -- (1) If either I'First or I'Last is not known at compile time, use
1458 -- I'Base instead of I in the next three steps and perform a
1459 -- regular range check against I'Range after conversion.
1460 -- (2) If I'First - 0.5 is representable in F then let Lo be that
1461 -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be
1462 -- F'Machine (T) and let Lo_OK be (Lo >= I'First). In other words,
1463 -- take one of the closest floating-point numbers to T, and see if
1464 -- it is in range or not.
1465 -- (3) If I'Last + 0.5 is representable in F then let Hi be that value
1466 -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be
1467 -- F'Rounding (T) and let Hi_OK be (Hi <= I'Last).
1468 -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo)
1469 -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi)
1471 procedure Apply_Float_Conversion_Check
1473 Target_Typ
: Entity_Id
)
1475 LB
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1476 HB
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1477 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1478 Expr_Type
: constant Entity_Id
:= Base_Type
(Etype
(Ck_Node
));
1479 Target_Base
: constant Entity_Id
:= Implementation_Base_Type
1481 Max_Bound
: constant Uint
:= UI_Expon
1482 (Machine_Radix
(Expr_Type
),
1483 Machine_Mantissa
(Expr_Type
) - 1) - 1;
1484 -- Largest bound, so bound plus or minus half is a machine number of F
1487 Ilast
: Uint
; -- Bounds of integer type
1488 Lo
, Hi
: Ureal
; -- Bounds to check in floating-point domain
1490 Hi_OK
: Boolean; -- True iff Lo resp. Hi belongs to I'Range
1493 Hi_Chk
: Node_Id
; -- Expressions that are False iff check fails
1495 Reason
: RT_Exception_Code
;
1498 if not Compile_Time_Known_Value
(LB
)
1499 or not Compile_Time_Known_Value
(HB
)
1502 -- First check that the value falls in the range of the base
1503 -- type, to prevent overflow during conversion and then
1504 -- perform a regular range check against the (dynamic) bounds.
1506 Par
: constant Node_Id
:= Parent
(Ck_Node
);
1508 pragma Assert
(Target_Base
/= Target_Typ
);
1509 pragma Assert
(Nkind
(Par
) = N_Type_Conversion
);
1511 Temp
: constant Entity_Id
:=
1512 Make_Defining_Identifier
(Loc
,
1513 Chars
=> New_Internal_Name
('T'));
1516 Apply_Float_Conversion_Check
(Ck_Node
, Target_Base
);
1517 Set_Etype
(Temp
, Target_Base
);
1519 Insert_Action
(Parent
(Par
),
1520 Make_Object_Declaration
(Loc
,
1521 Defining_Identifier
=> Temp
,
1522 Object_Definition
=> New_Occurrence_Of
(Target_Typ
, Loc
),
1523 Expression
=> New_Copy_Tree
(Par
)),
1524 Suppress
=> All_Checks
);
1527 Make_Raise_Constraint_Error
(Loc
,
1530 Left_Opnd
=> New_Occurrence_Of
(Temp
, Loc
),
1531 Right_Opnd
=> New_Occurrence_Of
(Target_Typ
, Loc
)),
1532 Reason
=> CE_Range_Check_Failed
));
1533 Rewrite
(Par
, New_Occurrence_Of
(Temp
, Loc
));
1539 -- Get the bounds of the target type
1541 Ifirst
:= Expr_Value
(LB
);
1542 Ilast
:= Expr_Value
(HB
);
1544 -- Check against lower bound
1546 if abs (Ifirst
) < Max_Bound
then
1547 Lo
:= UR_From_Uint
(Ifirst
) - Ureal_Half
;
1548 Lo_OK
:= (Ifirst
> 0);
1550 Lo
:= Machine
(Expr_Type
, UR_From_Uint
(Ifirst
), Round_Even
, Ck_Node
);
1551 Lo_OK
:= (Lo
>= UR_From_Uint
(Ifirst
));
1556 -- Lo_Chk := (X >= Lo)
1558 Lo_Chk
:= Make_Op_Ge
(Loc
,
1559 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1560 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
1563 -- Lo_Chk := (X > Lo)
1565 Lo_Chk
:= Make_Op_Gt
(Loc
,
1566 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1567 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
1570 -- Check against higher bound
1572 if abs (Ilast
) < Max_Bound
then
1573 Hi
:= UR_From_Uint
(Ilast
) + Ureal_Half
;
1574 Hi_OK
:= (Ilast
< 0);
1576 Hi
:= Machine
(Expr_Type
, UR_From_Uint
(Ilast
), Round_Even
, Ck_Node
);
1577 Hi_OK
:= (Hi
<= UR_From_Uint
(Ilast
));
1582 -- Hi_Chk := (X <= Hi)
1584 Hi_Chk
:= Make_Op_Le
(Loc
,
1585 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1586 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
1589 -- Hi_Chk := (X < Hi)
1591 Hi_Chk
:= Make_Op_Lt
(Loc
,
1592 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1593 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
1596 -- If the bounds of the target type are the same as those of the
1597 -- base type, the check is an overflow check as a range check is
1598 -- not performed in these cases.
1600 if Expr_Value
(Type_Low_Bound
(Target_Base
)) = Ifirst
1601 and then Expr_Value
(Type_High_Bound
(Target_Base
)) = Ilast
1603 Reason
:= CE_Overflow_Check_Failed
;
1605 Reason
:= CE_Range_Check_Failed
;
1608 -- Raise CE if either conditions does not hold
1610 Insert_Action
(Ck_Node
,
1611 Make_Raise_Constraint_Error
(Loc
,
1612 Condition
=> Make_Op_Not
(Loc
, Make_Op_And
(Loc
, Lo_Chk
, Hi_Chk
)),
1614 end Apply_Float_Conversion_Check
;
1616 ------------------------
1617 -- Apply_Length_Check --
1618 ------------------------
1620 procedure Apply_Length_Check
1622 Target_Typ
: Entity_Id
;
1623 Source_Typ
: Entity_Id
:= Empty
)
1626 Apply_Selected_Length_Checks
1627 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
1628 end Apply_Length_Check
;
1630 -----------------------
1631 -- Apply_Range_Check --
1632 -----------------------
1634 procedure Apply_Range_Check
1636 Target_Typ
: Entity_Id
;
1637 Source_Typ
: Entity_Id
:= Empty
)
1640 Apply_Selected_Range_Checks
1641 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
1642 end Apply_Range_Check
;
1644 ------------------------------
1645 -- Apply_Scalar_Range_Check --
1646 ------------------------------
1648 -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check
1649 -- flag off if it is already set on.
1651 procedure Apply_Scalar_Range_Check
1653 Target_Typ
: Entity_Id
;
1654 Source_Typ
: Entity_Id
:= Empty
;
1655 Fixed_Int
: Boolean := False)
1657 Parnt
: constant Node_Id
:= Parent
(Expr
);
1659 Arr
: Node_Id
:= Empty
; -- initialize to prevent warning
1660 Arr_Typ
: Entity_Id
:= Empty
; -- initialize to prevent warning
1663 Is_Subscr_Ref
: Boolean;
1664 -- Set true if Expr is a subscript
1666 Is_Unconstrained_Subscr_Ref
: Boolean;
1667 -- Set true if Expr is a subscript of an unconstrained array. In this
1668 -- case we do not attempt to do an analysis of the value against the
1669 -- range of the subscript, since we don't know the actual subtype.
1672 -- Set to True if Expr should be regarded as a real value
1673 -- even though the type of Expr might be discrete.
1675 procedure Bad_Value
;
1676 -- Procedure called if value is determined to be out of range
1682 procedure Bad_Value
is
1684 Apply_Compile_Time_Constraint_Error
1685 (Expr
, "value not in range of}?", CE_Range_Check_Failed
,
1690 -- Start of processing for Apply_Scalar_Range_Check
1693 if Inside_A_Generic
then
1696 -- Return if check obviously not needed. Note that we do not check
1697 -- for the expander being inactive, since this routine does not
1698 -- insert any code, but it does generate useful warnings sometimes,
1699 -- which we would like even if we are in semantics only mode.
1701 elsif Target_Typ
= Any_Type
1702 or else not Is_Scalar_Type
(Target_Typ
)
1703 or else Raises_Constraint_Error
(Expr
)
1708 -- Now, see if checks are suppressed
1711 Is_List_Member
(Expr
) and then Nkind
(Parnt
) = N_Indexed_Component
;
1713 if Is_Subscr_Ref
then
1714 Arr
:= Prefix
(Parnt
);
1715 Arr_Typ
:= Get_Actual_Subtype_If_Available
(Arr
);
1718 if not Do_Range_Check
(Expr
) then
1720 -- Subscript reference. Check for Index_Checks suppressed
1722 if Is_Subscr_Ref
then
1724 -- Check array type and its base type
1726 if Index_Checks_Suppressed
(Arr_Typ
)
1727 or else Index_Checks_Suppressed
(Base_Type
(Arr_Typ
))
1731 -- Check array itself if it is an entity name
1733 elsif Is_Entity_Name
(Arr
)
1734 and then Index_Checks_Suppressed
(Entity
(Arr
))
1738 -- Check expression itself if it is an entity name
1740 elsif Is_Entity_Name
(Expr
)
1741 and then Index_Checks_Suppressed
(Entity
(Expr
))
1746 -- All other cases, check for Range_Checks suppressed
1749 -- Check target type and its base type
1751 if Range_Checks_Suppressed
(Target_Typ
)
1752 or else Range_Checks_Suppressed
(Base_Type
(Target_Typ
))
1756 -- Check expression itself if it is an entity name
1758 elsif Is_Entity_Name
(Expr
)
1759 and then Range_Checks_Suppressed
(Entity
(Expr
))
1763 -- If Expr is part of an assignment statement, then check
1764 -- left side of assignment if it is an entity name.
1766 elsif Nkind
(Parnt
) = N_Assignment_Statement
1767 and then Is_Entity_Name
(Name
(Parnt
))
1768 and then Range_Checks_Suppressed
(Entity
(Name
(Parnt
)))
1775 -- Do not set range checks if they are killed
1777 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
1778 and then Kill_Range_Check
(Expr
)
1783 -- Do not set range checks for any values from System.Scalar_Values
1784 -- since the whole idea of such values is to avoid checking them!
1786 if Is_Entity_Name
(Expr
)
1787 and then Is_RTU
(Scope
(Entity
(Expr
)), System_Scalar_Values
)
1792 -- Now see if we need a check
1794 if No
(Source_Typ
) then
1795 S_Typ
:= Etype
(Expr
);
1797 S_Typ
:= Source_Typ
;
1800 if not Is_Scalar_Type
(S_Typ
) or else S_Typ
= Any_Type
then
1804 Is_Unconstrained_Subscr_Ref
:=
1805 Is_Subscr_Ref
and then not Is_Constrained
(Arr_Typ
);
1807 -- Always do a range check if the source type includes infinities
1808 -- and the target type does not include infinities. We do not do
1809 -- this if range checks are killed.
1811 if Is_Floating_Point_Type
(S_Typ
)
1812 and then Has_Infinities
(S_Typ
)
1813 and then not Has_Infinities
(Target_Typ
)
1815 Enable_Range_Check
(Expr
);
1818 -- Return if we know expression is definitely in the range of
1819 -- the target type as determined by Determine_Range. Right now
1820 -- we only do this for discrete types, and not fixed-point or
1821 -- floating-point types.
1823 -- The additional less-precise tests below catch these cases
1825 -- Note: skip this if we are given a source_typ, since the point
1826 -- of supplying a Source_Typ is to stop us looking at the expression.
1827 -- could sharpen this test to be out parameters only ???
1829 if Is_Discrete_Type
(Target_Typ
)
1830 and then Is_Discrete_Type
(Etype
(Expr
))
1831 and then not Is_Unconstrained_Subscr_Ref
1832 and then No
(Source_Typ
)
1835 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1836 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1841 if Compile_Time_Known_Value
(Tlo
)
1842 and then Compile_Time_Known_Value
(Thi
)
1845 Lov
: constant Uint
:= Expr_Value
(Tlo
);
1846 Hiv
: constant Uint
:= Expr_Value
(Thi
);
1849 -- If range is null, we for sure have a constraint error
1850 -- (we don't even need to look at the value involved,
1851 -- since all possible values will raise CE).
1858 -- Otherwise determine range of value
1860 Determine_Range
(Expr
, OK
, Lo
, Hi
);
1864 -- If definitely in range, all OK
1866 if Lo
>= Lov
and then Hi
<= Hiv
then
1869 -- If definitely not in range, warn
1871 elsif Lov
> Hi
or else Hiv
< Lo
then
1875 -- Otherwise we don't know
1887 Is_Floating_Point_Type
(S_Typ
)
1888 or else (Is_Fixed_Point_Type
(S_Typ
) and then not Fixed_Int
);
1890 -- Check if we can determine at compile time whether Expr is in the
1891 -- range of the target type. Note that if S_Typ is within the bounds
1892 -- of Target_Typ then this must be the case. This check is meaningful
1893 -- only if this is not a conversion between integer and real types.
1895 if not Is_Unconstrained_Subscr_Ref
1897 Is_Discrete_Type
(S_Typ
) = Is_Discrete_Type
(Target_Typ
)
1899 (In_Subrange_Of
(S_Typ
, Target_Typ
, Fixed_Int
)
1901 Is_In_Range
(Expr
, Target_Typ
, Fixed_Int
, Int_Real
))
1905 elsif Is_Out_Of_Range
(Expr
, Target_Typ
, Fixed_Int
, Int_Real
) then
1909 -- In the floating-point case, we only do range checks if the
1910 -- type is constrained. We definitely do NOT want range checks
1911 -- for unconstrained types, since we want to have infinities
1913 elsif Is_Floating_Point_Type
(S_Typ
) then
1914 if Is_Constrained
(S_Typ
) then
1915 Enable_Range_Check
(Expr
);
1918 -- For all other cases we enable a range check unconditionally
1921 Enable_Range_Check
(Expr
);
1924 end Apply_Scalar_Range_Check
;
1926 ----------------------------------
1927 -- Apply_Selected_Length_Checks --
1928 ----------------------------------
1930 procedure Apply_Selected_Length_Checks
1932 Target_Typ
: Entity_Id
;
1933 Source_Typ
: Entity_Id
;
1934 Do_Static
: Boolean)
1937 R_Result
: Check_Result
;
1940 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1941 Checks_On
: constant Boolean :=
1942 (not Index_Checks_Suppressed
(Target_Typ
))
1944 (not Length_Checks_Suppressed
(Target_Typ
));
1947 if not Expander_Active
then
1952 Selected_Length_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
1954 for J
in 1 .. 2 loop
1955 R_Cno
:= R_Result
(J
);
1956 exit when No
(R_Cno
);
1958 -- A length check may mention an Itype which is attached to a
1959 -- subsequent node. At the top level in a package this can cause
1960 -- an order-of-elaboration problem, so we make sure that the itype
1961 -- is referenced now.
1963 if Ekind
(Current_Scope
) = E_Package
1964 and then Is_Compilation_Unit
(Current_Scope
)
1966 Ensure_Defined
(Target_Typ
, Ck_Node
);
1968 if Present
(Source_Typ
) then
1969 Ensure_Defined
(Source_Typ
, Ck_Node
);
1971 elsif Is_Itype
(Etype
(Ck_Node
)) then
1972 Ensure_Defined
(Etype
(Ck_Node
), Ck_Node
);
1976 -- If the item is a conditional raise of constraint error,
1977 -- then have a look at what check is being performed and
1980 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
1981 and then Present
(Condition
(R_Cno
))
1983 Cond
:= Condition
(R_Cno
);
1985 if not Has_Dynamic_Length_Check
(Ck_Node
)
1988 Insert_Action
(Ck_Node
, R_Cno
);
1990 if not Do_Static
then
1991 Set_Has_Dynamic_Length_Check
(Ck_Node
);
1995 -- Output a warning if the condition is known to be True
1997 if Is_Entity_Name
(Cond
)
1998 and then Entity
(Cond
) = Standard_True
2000 Apply_Compile_Time_Constraint_Error
2001 (Ck_Node
, "wrong length for array of}?",
2002 CE_Length_Check_Failed
,
2006 -- If we were only doing a static check, or if checks are not
2007 -- on, then we want to delete the check, since it is not needed.
2008 -- We do this by replacing the if statement by a null statement
2010 elsif Do_Static
or else not Checks_On
then
2011 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
2015 Install_Static_Check
(R_Cno
, Loc
);
2020 end Apply_Selected_Length_Checks
;
2022 ---------------------------------
2023 -- Apply_Selected_Range_Checks --
2024 ---------------------------------
2026 procedure Apply_Selected_Range_Checks
2028 Target_Typ
: Entity_Id
;
2029 Source_Typ
: Entity_Id
;
2030 Do_Static
: Boolean)
2033 R_Result
: Check_Result
;
2036 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
2037 Checks_On
: constant Boolean :=
2038 (not Index_Checks_Suppressed
(Target_Typ
))
2040 (not Range_Checks_Suppressed
(Target_Typ
));
2043 if not Expander_Active
or else not Checks_On
then
2048 Selected_Range_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
2050 for J
in 1 .. 2 loop
2052 R_Cno
:= R_Result
(J
);
2053 exit when No
(R_Cno
);
2055 -- If the item is a conditional raise of constraint error,
2056 -- then have a look at what check is being performed and
2059 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
2060 and then Present
(Condition
(R_Cno
))
2062 Cond
:= Condition
(R_Cno
);
2064 if not Has_Dynamic_Range_Check
(Ck_Node
) then
2065 Insert_Action
(Ck_Node
, R_Cno
);
2067 if not Do_Static
then
2068 Set_Has_Dynamic_Range_Check
(Ck_Node
);
2072 -- Output a warning if the condition is known to be True
2074 if Is_Entity_Name
(Cond
)
2075 and then Entity
(Cond
) = Standard_True
2077 -- Since an N_Range is technically not an expression, we
2078 -- have to set one of the bounds to C_E and then just flag
2079 -- the N_Range. The warning message will point to the
2080 -- lower bound and complain about a range, which seems OK.
2082 if Nkind
(Ck_Node
) = N_Range
then
2083 Apply_Compile_Time_Constraint_Error
2084 (Low_Bound
(Ck_Node
), "static range out of bounds of}?",
2085 CE_Range_Check_Failed
,
2089 Set_Raises_Constraint_Error
(Ck_Node
);
2092 Apply_Compile_Time_Constraint_Error
2093 (Ck_Node
, "static value out of range of}?",
2094 CE_Range_Check_Failed
,
2099 -- If we were only doing a static check, or if checks are not
2100 -- on, then we want to delete the check, since it is not needed.
2101 -- We do this by replacing the if statement by a null statement
2103 elsif Do_Static
or else not Checks_On
then
2104 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
2108 Install_Static_Check
(R_Cno
, Loc
);
2111 end Apply_Selected_Range_Checks
;
2113 -------------------------------
2114 -- Apply_Static_Length_Check --
2115 -------------------------------
2117 procedure Apply_Static_Length_Check
2119 Target_Typ
: Entity_Id
;
2120 Source_Typ
: Entity_Id
:= Empty
)
2123 Apply_Selected_Length_Checks
2124 (Expr
, Target_Typ
, Source_Typ
, Do_Static
=> True);
2125 end Apply_Static_Length_Check
;
2127 -------------------------------------
2128 -- Apply_Subscript_Validity_Checks --
2129 -------------------------------------
2131 procedure Apply_Subscript_Validity_Checks
(Expr
: Node_Id
) is
2135 pragma Assert
(Nkind
(Expr
) = N_Indexed_Component
);
2137 -- Loop through subscripts
2139 Sub
:= First
(Expressions
(Expr
));
2140 while Present
(Sub
) loop
2142 -- Check one subscript. Note that we do not worry about
2143 -- enumeration type with holes, since we will convert the
2144 -- value to a Pos value for the subscript, and that convert
2145 -- will do the necessary validity check.
2147 Ensure_Valid
(Sub
, Holes_OK
=> True);
2149 -- Move to next subscript
2153 end Apply_Subscript_Validity_Checks
;
2155 ----------------------------------
2156 -- Apply_Type_Conversion_Checks --
2157 ----------------------------------
2159 procedure Apply_Type_Conversion_Checks
(N
: Node_Id
) is
2160 Target_Type
: constant Entity_Id
:= Etype
(N
);
2161 Target_Base
: constant Entity_Id
:= Base_Type
(Target_Type
);
2162 Expr
: constant Node_Id
:= Expression
(N
);
2163 Expr_Type
: constant Entity_Id
:= Etype
(Expr
);
2166 if Inside_A_Generic
then
2169 -- Skip these checks if serious errors detected, there are some nasty
2170 -- situations of incomplete trees that blow things up.
2172 elsif Serious_Errors_Detected
> 0 then
2175 -- Scalar type conversions of the form Target_Type (Expr) require
2176 -- a range check if we cannot be sure that Expr is in the base type
2177 -- of Target_Typ and also that Expr is in the range of Target_Typ.
2178 -- These are not quite the same condition from an implementation
2179 -- point of view, but clearly the second includes the first.
2181 elsif Is_Scalar_Type
(Target_Type
) then
2183 Conv_OK
: constant Boolean := Conversion_OK
(N
);
2184 -- If the Conversion_OK flag on the type conversion is set
2185 -- and no floating point type is involved in the type conversion
2186 -- then fixed point values must be read as integral values.
2188 Float_To_Int
: constant Boolean :=
2189 Is_Floating_Point_Type
(Expr_Type
)
2190 and then Is_Integer_Type
(Target_Type
);
2193 if not Overflow_Checks_Suppressed
(Target_Base
)
2194 and then not In_Subrange_Of
(Expr_Type
, Target_Base
, Conv_OK
)
2195 and then not Float_To_Int
2197 Set_Do_Overflow_Check
(N
);
2200 if not Range_Checks_Suppressed
(Target_Type
)
2201 and then not Range_Checks_Suppressed
(Expr_Type
)
2203 if Float_To_Int
then
2204 Apply_Float_Conversion_Check
(Expr
, Target_Type
);
2206 Apply_Scalar_Range_Check
2207 (Expr
, Target_Type
, Fixed_Int
=> Conv_OK
);
2212 elsif Comes_From_Source
(N
)
2213 and then Is_Record_Type
(Target_Type
)
2214 and then Is_Derived_Type
(Target_Type
)
2215 and then not Is_Tagged_Type
(Target_Type
)
2216 and then not Is_Constrained
(Target_Type
)
2217 and then Present
(Stored_Constraint
(Target_Type
))
2219 -- An unconstrained derived type may have inherited discriminant
2220 -- Build an actual discriminant constraint list using the stored
2221 -- constraint, to verify that the expression of the parent type
2222 -- satisfies the constraints imposed by the (unconstrained!)
2223 -- derived type. This applies to value conversions, not to view
2224 -- conversions of tagged types.
2227 Loc
: constant Source_Ptr
:= Sloc
(N
);
2229 Constraint
: Elmt_Id
;
2230 Discr_Value
: Node_Id
;
2233 New_Constraints
: constant Elist_Id
:= New_Elmt_List
;
2234 Old_Constraints
: constant Elist_Id
:=
2235 Discriminant_Constraint
(Expr_Type
);
2238 Constraint
:= First_Elmt
(Stored_Constraint
(Target_Type
));
2240 while Present
(Constraint
) loop
2241 Discr_Value
:= Node
(Constraint
);
2243 if Is_Entity_Name
(Discr_Value
)
2244 and then Ekind
(Entity
(Discr_Value
)) = E_Discriminant
2246 Discr
:= Corresponding_Discriminant
(Entity
(Discr_Value
));
2249 and then Scope
(Discr
) = Base_Type
(Expr_Type
)
2251 -- Parent is constrained by new discriminant. Obtain
2252 -- Value of original discriminant in expression. If
2253 -- the new discriminant has been used to constrain more
2254 -- than one of the stored discriminants, this will
2255 -- provide the required consistency check.
2258 Make_Selected_Component
(Loc
,
2260 Duplicate_Subexpr_No_Checks
2261 (Expr
, Name_Req
=> True),
2263 Make_Identifier
(Loc
, Chars
(Discr
))),
2267 -- Discriminant of more remote ancestor ???
2272 -- Derived type definition has an explicit value for
2273 -- this stored discriminant.
2277 (Duplicate_Subexpr_No_Checks
(Discr_Value
),
2281 Next_Elmt
(Constraint
);
2284 -- Use the unconstrained expression type to retrieve the
2285 -- discriminants of the parent, and apply momentarily the
2286 -- discriminant constraint synthesized above.
2288 Set_Discriminant_Constraint
(Expr_Type
, New_Constraints
);
2289 Cond
:= Build_Discriminant_Checks
(Expr
, Expr_Type
);
2290 Set_Discriminant_Constraint
(Expr_Type
, Old_Constraints
);
2293 Make_Raise_Constraint_Error
(Loc
,
2295 Reason
=> CE_Discriminant_Check_Failed
));
2298 -- For arrays, conversions are applied during expansion, to take
2299 -- into accounts changes of representation. The checks become range
2300 -- checks on the base type or length checks on the subtype, depending
2301 -- on whether the target type is unconstrained or constrained.
2306 end Apply_Type_Conversion_Checks
;
2308 ----------------------------------------------
2309 -- Apply_Universal_Integer_Attribute_Checks --
2310 ----------------------------------------------
2312 procedure Apply_Universal_Integer_Attribute_Checks
(N
: Node_Id
) is
2313 Loc
: constant Source_Ptr
:= Sloc
(N
);
2314 Typ
: constant Entity_Id
:= Etype
(N
);
2317 if Inside_A_Generic
then
2320 -- Nothing to do if checks are suppressed
2322 elsif Range_Checks_Suppressed
(Typ
)
2323 and then Overflow_Checks_Suppressed
(Typ
)
2327 -- Nothing to do if the attribute does not come from source. The
2328 -- internal attributes we generate of this type do not need checks,
2329 -- and furthermore the attempt to check them causes some circular
2330 -- elaboration orders when dealing with packed types.
2332 elsif not Comes_From_Source
(N
) then
2335 -- If the prefix is a selected component that depends on a discriminant
2336 -- the check may improperly expose a discriminant instead of using
2337 -- the bounds of the object itself. Set the type of the attribute to
2338 -- the base type of the context, so that a check will be imposed when
2339 -- needed (e.g. if the node appears as an index).
2341 elsif Nkind
(Prefix
(N
)) = N_Selected_Component
2342 and then Ekind
(Typ
) = E_Signed_Integer_Subtype
2343 and then Depends_On_Discriminant
(Scalar_Range
(Typ
))
2345 Set_Etype
(N
, Base_Type
(Typ
));
2347 -- Otherwise, replace the attribute node with a type conversion
2348 -- node whose expression is the attribute, retyped to universal
2349 -- integer, and whose subtype mark is the target type. The call
2350 -- to analyze this conversion will set range and overflow checks
2351 -- as required for proper detection of an out of range value.
2354 Set_Etype
(N
, Universal_Integer
);
2355 Set_Analyzed
(N
, True);
2358 Make_Type_Conversion
(Loc
,
2359 Subtype_Mark
=> New_Occurrence_Of
(Typ
, Loc
),
2360 Expression
=> Relocate_Node
(N
)));
2362 Analyze_And_Resolve
(N
, Typ
);
2366 end Apply_Universal_Integer_Attribute_Checks
;
2368 -------------------------------
2369 -- Build_Discriminant_Checks --
2370 -------------------------------
2372 function Build_Discriminant_Checks
2374 T_Typ
: Entity_Id
) return Node_Id
2376 Loc
: constant Source_Ptr
:= Sloc
(N
);
2379 Disc_Ent
: Entity_Id
;
2385 Disc
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
2387 -- For a fully private type, use the discriminants of the parent type
2389 if Is_Private_Type
(T_Typ
)
2390 and then No
(Full_View
(T_Typ
))
2392 Disc_Ent
:= First_Discriminant
(Etype
(Base_Type
(T_Typ
)));
2394 Disc_Ent
:= First_Discriminant
(T_Typ
);
2397 while Present
(Disc
) loop
2398 Dval
:= Node
(Disc
);
2400 if Nkind
(Dval
) = N_Identifier
2401 and then Ekind
(Entity
(Dval
)) = E_Discriminant
2403 Dval
:= New_Occurrence_Of
(Discriminal
(Entity
(Dval
)), Loc
);
2405 Dval
:= Duplicate_Subexpr_No_Checks
(Dval
);
2408 -- If we have an Unchecked_Union node, we can infer the discriminants
2411 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
2413 Get_Discriminant_Value
(
2414 First_Discriminant
(T_Typ
),
2416 Stored_Constraint
(T_Typ
)));
2420 Make_Selected_Component
(Loc
,
2422 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
2424 Make_Identifier
(Loc
, Chars
(Disc_Ent
)));
2426 Set_Is_In_Discriminant_Check
(Dref
);
2429 Evolve_Or_Else
(Cond
,
2432 Right_Opnd
=> Dval
));
2435 Next_Discriminant
(Disc_Ent
);
2439 end Build_Discriminant_Checks
;
2441 -----------------------------------
2442 -- Check_Valid_Lvalue_Subscripts --
2443 -----------------------------------
2445 procedure Check_Valid_Lvalue_Subscripts
(Expr
: Node_Id
) is
2447 -- Skip this if range checks are suppressed
2449 if Range_Checks_Suppressed
(Etype
(Expr
)) then
2452 -- Only do this check for expressions that come from source. We
2453 -- assume that expander generated assignments explicitly include
2454 -- any necessary checks. Note that this is not just an optimization,
2455 -- it avoids infinite recursions!
2457 elsif not Comes_From_Source
(Expr
) then
2460 -- For a selected component, check the prefix
2462 elsif Nkind
(Expr
) = N_Selected_Component
then
2463 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
2466 -- Case of indexed component
2468 elsif Nkind
(Expr
) = N_Indexed_Component
then
2469 Apply_Subscript_Validity_Checks
(Expr
);
2471 -- Prefix may itself be or contain an indexed component, and
2472 -- these subscripts need checking as well
2474 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
2476 end Check_Valid_Lvalue_Subscripts
;
2478 ----------------------------------
2479 -- Null_Exclusion_Static_Checks --
2480 ----------------------------------
2482 procedure Null_Exclusion_Static_Checks
(N
: Node_Id
) is
2483 K
: constant Node_Kind
:= Nkind
(N
);
2485 Related_Nod
: Node_Id
;
2486 Has_Null_Exclusion
: Boolean := False;
2488 type Msg_Kind
is (Components
, Formals
, Objects
);
2489 Msg_K
: Msg_Kind
:= Objects
;
2490 -- Used by local subprograms to generate precise error messages
2492 procedure Check_Must_Be_Access
2494 Has_Null_Exclusion
: Boolean);
2495 -- ??? local subprograms must have comment on spec
2497 procedure Check_Already_Null_Excluding_Type
2499 Has_Null_Exclusion
: Boolean;
2500 Related_Nod
: Node_Id
);
2501 -- ??? local subprograms must have comment on spec
2503 procedure Check_Must_Be_Initialized
2505 Related_Nod
: Node_Id
);
2506 -- ??? local subprograms must have comment on spec
2508 procedure Check_Null_Not_Allowed
(N
: Node_Id
);
2509 -- ??? local subprograms must have comment on spec
2511 -- ??? following bodies lack comments
2513 --------------------------
2514 -- Check_Must_Be_Access --
2515 --------------------------
2517 procedure Check_Must_Be_Access
2519 Has_Null_Exclusion
: Boolean)
2522 if Has_Null_Exclusion
2523 and then not Is_Access_Type
(Typ
)
2525 Error_Msg_N
("(Ada 2005) must be an access type", Related_Nod
);
2527 end Check_Must_Be_Access
;
2529 ---------------------------------------
2530 -- Check_Already_Null_Excluding_Type --
2531 ---------------------------------------
2533 procedure Check_Already_Null_Excluding_Type
2535 Has_Null_Exclusion
: Boolean;
2536 Related_Nod
: Node_Id
)
2539 if Has_Null_Exclusion
2540 and then Can_Never_Be_Null
(Typ
)
2543 ("(Ada 2005) already a null-excluding type", Related_Nod
);
2545 end Check_Already_Null_Excluding_Type
;
2547 -------------------------------
2548 -- Check_Must_Be_Initialized --
2549 -------------------------------
2551 procedure Check_Must_Be_Initialized
2553 Related_Nod
: Node_Id
)
2555 Expr
: constant Node_Id
:= Expression
(N
);
2558 pragma Assert
(Nkind
(N
) = N_Component_Declaration
2559 or else Nkind
(N
) = N_Object_Declaration
);
2561 if not Present
(Expr
) then
2565 ("(Ada 2005) null-excluding components must be " &
2566 "initialized", Related_Nod
);
2570 ("(Ada 2005) null-excluding formals must be initialized",
2575 ("(Ada 2005) null-excluding objects must be initialized",
2579 end Check_Must_Be_Initialized
;
2581 ----------------------------
2582 -- Check_Null_Not_Allowed --
2583 ----------------------------
2585 procedure Check_Null_Not_Allowed
(N
: Node_Id
) is
2586 Expr
: constant Node_Id
:= Expression
(N
);
2590 and then Nkind
(Expr
) = N_Null
2595 ("(Ada 2005) NULL not allowed in null-excluding " &
2596 "components", Expr
);
2600 ("(Ada 2005) NULL not allowed in null-excluding formals",
2605 ("(Ada 2005) NULL not allowed in null-excluding objects",
2609 end Check_Null_Not_Allowed
;
2611 -- Start of processing for Null_Exclusion_Static_Checks
2614 pragma Assert
(K
= N_Component_Declaration
2615 or else K
= N_Parameter_Specification
2616 or else K
= N_Object_Declaration
2617 or else K
= N_Discriminant_Specification
2618 or else K
= N_Allocator
);
2621 when N_Component_Declaration
=>
2622 Msg_K
:= Components
;
2624 if not Present
(Access_Definition
(Component_Definition
(N
))) then
2625 Has_Null_Exclusion
:= Null_Exclusion_Present
2626 (Component_Definition
(N
));
2627 Typ
:= Etype
(Subtype_Indication
(Component_Definition
(N
)));
2628 Related_Nod
:= Subtype_Indication
(Component_Definition
(N
));
2629 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2630 Check_Already_Null_Excluding_Type
2631 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2632 Check_Must_Be_Initialized
(N
, Related_Nod
);
2635 Check_Null_Not_Allowed
(N
);
2637 when N_Parameter_Specification
=>
2639 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2640 Typ
:= Entity
(Parameter_Type
(N
));
2641 Related_Nod
:= Parameter_Type
(N
);
2642 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2643 Check_Already_Null_Excluding_Type
2644 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2645 Check_Null_Not_Allowed
(N
);
2647 when N_Object_Declaration
=>
2649 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2650 Typ
:= Entity
(Object_Definition
(N
));
2651 Related_Nod
:= Object_Definition
(N
);
2652 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2653 Check_Already_Null_Excluding_Type
2654 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2655 Check_Must_Be_Initialized
(N
, Related_Nod
);
2656 Check_Null_Not_Allowed
(N
);
2658 when N_Discriminant_Specification
=>
2659 Msg_K
:= Components
;
2661 if Nkind
(Discriminant_Type
(N
)) /= N_Access_Definition
then
2662 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2663 Typ
:= Etype
(Defining_Identifier
(N
));
2664 Related_Nod
:= Discriminant_Type
(N
);
2665 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2666 Check_Already_Null_Excluding_Type
2667 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2670 Check_Null_Not_Allowed
(N
);
2674 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2675 Typ
:= Etype
(Expression
(N
));
2677 if Nkind
(Expression
(N
)) = N_Qualified_Expression
then
2678 Related_Nod
:= Subtype_Mark
(Expression
(N
));
2680 Related_Nod
:= Expression
(N
);
2683 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2684 Check_Already_Null_Excluding_Type
2685 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2686 Check_Null_Not_Allowed
(N
);
2689 raise Program_Error
;
2691 end Null_Exclusion_Static_Checks
;
2693 ----------------------------------
2694 -- Conditional_Statements_Begin --
2695 ----------------------------------
2697 procedure Conditional_Statements_Begin
is
2699 Saved_Checks_TOS
:= Saved_Checks_TOS
+ 1;
2701 -- If stack overflows, kill all checks, that way we know to
2702 -- simply reset the number of saved checks to zero on return.
2703 -- This should never occur in practice.
2705 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
2708 -- In the normal case, we just make a new stack entry saving
2709 -- the current number of saved checks for a later restore.
2712 Saved_Checks_Stack
(Saved_Checks_TOS
) := Num_Saved_Checks
;
2714 if Debug_Flag_CC
then
2715 w
("Conditional_Statements_Begin: Num_Saved_Checks = ",
2719 end Conditional_Statements_Begin
;
2721 --------------------------------
2722 -- Conditional_Statements_End --
2723 --------------------------------
2725 procedure Conditional_Statements_End
is
2727 pragma Assert
(Saved_Checks_TOS
> 0);
2729 -- If the saved checks stack overflowed, then we killed all
2730 -- checks, so setting the number of saved checks back to
2731 -- zero is correct. This should never occur in practice.
2733 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
2734 Num_Saved_Checks
:= 0;
2736 -- In the normal case, restore the number of saved checks
2737 -- from the top stack entry.
2740 Num_Saved_Checks
:= Saved_Checks_Stack
(Saved_Checks_TOS
);
2741 if Debug_Flag_CC
then
2742 w
("Conditional_Statements_End: Num_Saved_Checks = ",
2747 Saved_Checks_TOS
:= Saved_Checks_TOS
- 1;
2748 end Conditional_Statements_End
;
2750 ---------------------
2751 -- Determine_Range --
2752 ---------------------
2754 Cache_Size
: constant := 2 ** 10;
2755 type Cache_Index
is range 0 .. Cache_Size
- 1;
2756 -- Determine size of below cache (power of 2 is more efficient!)
2758 Determine_Range_Cache_N
: array (Cache_Index
) of Node_Id
;
2759 Determine_Range_Cache_Lo
: array (Cache_Index
) of Uint
;
2760 Determine_Range_Cache_Hi
: array (Cache_Index
) of Uint
;
2761 -- The above arrays are used to implement a small direct cache
2762 -- for Determine_Range calls. Because of the way Determine_Range
2763 -- recursively traces subexpressions, and because overflow checking
2764 -- calls the routine on the way up the tree, a quadratic behavior
2765 -- can otherwise be encountered in large expressions. The cache
2766 -- entry for node N is stored in the (N mod Cache_Size) entry, and
2767 -- can be validated by checking the actual node value stored there.
2769 procedure Determine_Range
2775 Typ
: constant Entity_Id
:= Etype
(N
);
2779 -- Lo and Hi bounds of left operand
2783 -- Lo and Hi bounds of right (or only) operand
2786 -- Temp variable used to hold a bound node
2789 -- High bound of base type of expression
2793 -- Refined values for low and high bounds, after tightening
2796 -- Used in lower level calls to indicate if call succeeded
2798 Cindex
: Cache_Index
;
2799 -- Used to search cache
2801 function OK_Operands
return Boolean;
2802 -- Used for binary operators. Determines the ranges of the left and
2803 -- right operands, and if they are both OK, returns True, and puts
2804 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left
2810 function OK_Operands
return Boolean is
2812 Determine_Range
(Left_Opnd
(N
), OK1
, Lo_Left
, Hi_Left
);
2818 Determine_Range
(Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
);
2822 -- Start of processing for Determine_Range
2825 -- Prevent junk warnings by initializing range variables
2832 -- If the type is not discrete, or is undefined, then we can't
2833 -- do anything about determining the range.
2835 if No
(Typ
) or else not Is_Discrete_Type
(Typ
)
2836 or else Error_Posted
(N
)
2842 -- For all other cases, we can determine the range
2846 -- If value is compile time known, then the possible range is the
2847 -- one value that we know this expression definitely has!
2849 if Compile_Time_Known_Value
(N
) then
2850 Lo
:= Expr_Value
(N
);
2855 -- Return if already in the cache
2857 Cindex
:= Cache_Index
(N
mod Cache_Size
);
2859 if Determine_Range_Cache_N
(Cindex
) = N
then
2860 Lo
:= Determine_Range_Cache_Lo
(Cindex
);
2861 Hi
:= Determine_Range_Cache_Hi
(Cindex
);
2865 -- Otherwise, start by finding the bounds of the type of the
2866 -- expression, the value cannot be outside this range (if it
2867 -- is, then we have an overflow situation, which is a separate
2868 -- check, we are talking here only about the expression value).
2870 -- We use the actual bound unless it is dynamic, in which case
2871 -- use the corresponding base type bound if possible. If we can't
2872 -- get a bound then we figure we can't determine the range (a
2873 -- peculiar case, that perhaps cannot happen, but there is no
2874 -- point in bombing in this optimization circuit.
2876 -- First the low bound
2878 Bound
:= Type_Low_Bound
(Typ
);
2880 if Compile_Time_Known_Value
(Bound
) then
2881 Lo
:= Expr_Value
(Bound
);
2883 elsif Compile_Time_Known_Value
(Type_Low_Bound
(Base_Type
(Typ
))) then
2884 Lo
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
2891 -- Now the high bound
2893 Bound
:= Type_High_Bound
(Typ
);
2895 -- We need the high bound of the base type later on, and this should
2896 -- always be compile time known. Again, it is not clear that this
2897 -- can ever be false, but no point in bombing.
2899 if Compile_Time_Known_Value
(Type_High_Bound
(Base_Type
(Typ
))) then
2900 Hbound
:= Expr_Value
(Type_High_Bound
(Base_Type
(Typ
)));
2908 -- If we have a static subtype, then that may have a tighter bound
2909 -- so use the upper bound of the subtype instead in this case.
2911 if Compile_Time_Known_Value
(Bound
) then
2912 Hi
:= Expr_Value
(Bound
);
2915 -- We may be able to refine this value in certain situations. If
2916 -- refinement is possible, then Lor and Hir are set to possibly
2917 -- tighter bounds, and OK1 is set to True.
2921 -- For unary plus, result is limited by range of operand
2924 Determine_Range
(Right_Opnd
(N
), OK1
, Lor
, Hir
);
2926 -- For unary minus, determine range of operand, and negate it
2929 Determine_Range
(Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
);
2936 -- For binary addition, get range of each operand and do the
2937 -- addition to get the result range.
2941 Lor
:= Lo_Left
+ Lo_Right
;
2942 Hir
:= Hi_Left
+ Hi_Right
;
2945 -- Division is tricky. The only case we consider is where the
2946 -- right operand is a positive constant, and in this case we
2947 -- simply divide the bounds of the left operand
2951 if Lo_Right
= Hi_Right
2952 and then Lo_Right
> 0
2954 Lor
:= Lo_Left
/ Lo_Right
;
2955 Hir
:= Hi_Left
/ Lo_Right
;
2962 -- For binary subtraction, get range of each operand and do
2963 -- the worst case subtraction to get the result range.
2965 when N_Op_Subtract
=>
2967 Lor
:= Lo_Left
- Hi_Right
;
2968 Hir
:= Hi_Left
- Lo_Right
;
2971 -- For MOD, if right operand is a positive constant, then
2972 -- result must be in the allowable range of mod results.
2976 if Lo_Right
= Hi_Right
2977 and then Lo_Right
/= 0
2979 if Lo_Right
> 0 then
2981 Hir
:= Lo_Right
- 1;
2983 else -- Lo_Right < 0
2984 Lor
:= Lo_Right
+ 1;
2993 -- For REM, if right operand is a positive constant, then
2994 -- result must be in the allowable range of mod results.
2998 if Lo_Right
= Hi_Right
2999 and then Lo_Right
/= 0
3002 Dval
: constant Uint
:= (abs Lo_Right
) - 1;
3005 -- The sign of the result depends on the sign of the
3006 -- dividend (but not on the sign of the divisor, hence
3007 -- the abs operation above).
3027 -- Attribute reference cases
3029 when N_Attribute_Reference
=>
3030 case Attribute_Name
(N
) is
3032 -- For Pos/Val attributes, we can refine the range using the
3033 -- possible range of values of the attribute expression
3035 when Name_Pos | Name_Val
=>
3036 Determine_Range
(First
(Expressions
(N
)), OK1
, Lor
, Hir
);
3038 -- For Length attribute, use the bounds of the corresponding
3039 -- index type to refine the range.
3043 Atyp
: Entity_Id
:= Etype
(Prefix
(N
));
3051 if Is_Access_Type
(Atyp
) then
3052 Atyp
:= Designated_Type
(Atyp
);
3055 -- For string literal, we know exact value
3057 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
3059 Lo
:= String_Literal_Length
(Atyp
);
3060 Hi
:= String_Literal_Length
(Atyp
);
3064 -- Otherwise check for expression given
3066 if No
(Expressions
(N
)) then
3070 UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
3073 Indx
:= First_Index
(Atyp
);
3074 for J
in 2 .. Inum
loop
3075 Indx
:= Next_Index
(Indx
);
3079 (Type_Low_Bound
(Etype
(Indx
)), OK1
, LL
, LU
);
3083 (Type_High_Bound
(Etype
(Indx
)), OK1
, UL
, UU
);
3087 -- The maximum value for Length is the biggest
3088 -- possible gap between the values of the bounds.
3089 -- But of course, this value cannot be negative.
3091 Hir
:= UI_Max
(Uint_0
, UU
- LL
);
3093 -- For constrained arrays, the minimum value for
3094 -- Length is taken from the actual value of the
3095 -- bounds, since the index will be exactly of
3098 if Is_Constrained
(Atyp
) then
3099 Lor
:= UI_Max
(Uint_0
, UL
- LU
);
3101 -- For an unconstrained array, the minimum value
3102 -- for length is always zero.
3111 -- No special handling for other attributes
3112 -- Probably more opportunities exist here ???
3119 -- For type conversion from one discrete type to another, we
3120 -- can refine the range using the converted value.
3122 when N_Type_Conversion
=>
3123 Determine_Range
(Expression
(N
), OK1
, Lor
, Hir
);
3125 -- Nothing special to do for all other expression kinds
3133 -- At this stage, if OK1 is true, then we know that the actual
3134 -- result of the computed expression is in the range Lor .. Hir.
3135 -- We can use this to restrict the possible range of results.
3139 -- If the refined value of the low bound is greater than the
3140 -- type high bound, then reset it to the more restrictive
3141 -- value. However, we do NOT do this for the case of a modular
3142 -- type where the possible upper bound on the value is above the
3143 -- base type high bound, because that means the result could wrap.
3146 and then not (Is_Modular_Integer_Type
(Typ
)
3147 and then Hir
> Hbound
)
3152 -- Similarly, if the refined value of the high bound is less
3153 -- than the value so far, then reset it to the more restrictive
3154 -- value. Again, we do not do this if the refined low bound is
3155 -- negative for a modular type, since this would wrap.
3158 and then not (Is_Modular_Integer_Type
(Typ
)
3159 and then Lor
< Uint_0
)
3165 -- Set cache entry for future call and we are all done
3167 Determine_Range_Cache_N
(Cindex
) := N
;
3168 Determine_Range_Cache_Lo
(Cindex
) := Lo
;
3169 Determine_Range_Cache_Hi
(Cindex
) := Hi
;
3172 -- If any exception occurs, it means that we have some bug in the compiler
3173 -- possibly triggered by a previous error, or by some unforseen peculiar
3174 -- occurrence. However, this is only an optimization attempt, so there is
3175 -- really no point in crashing the compiler. Instead we just decide, too
3176 -- bad, we can't figure out a range in this case after all.
3181 -- Debug flag K disables this behavior (useful for debugging)
3183 if Debug_Flag_K
then
3191 end Determine_Range
;
3193 ------------------------------------
3194 -- Discriminant_Checks_Suppressed --
3195 ------------------------------------
3197 function Discriminant_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3200 if Is_Unchecked_Union
(E
) then
3202 elsif Checks_May_Be_Suppressed
(E
) then
3203 return Is_Check_Suppressed
(E
, Discriminant_Check
);
3207 return Scope_Suppress
(Discriminant_Check
);
3208 end Discriminant_Checks_Suppressed
;
3210 --------------------------------
3211 -- Division_Checks_Suppressed --
3212 --------------------------------
3214 function Division_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3216 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
3217 return Is_Check_Suppressed
(E
, Division_Check
);
3219 return Scope_Suppress
(Division_Check
);
3221 end Division_Checks_Suppressed
;
3223 -----------------------------------
3224 -- Elaboration_Checks_Suppressed --
3225 -----------------------------------
3227 function Elaboration_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3230 if Kill_Elaboration_Checks
(E
) then
3232 elsif Checks_May_Be_Suppressed
(E
) then
3233 return Is_Check_Suppressed
(E
, Elaboration_Check
);
3237 return Scope_Suppress
(Elaboration_Check
);
3238 end Elaboration_Checks_Suppressed
;
3240 ---------------------------
3241 -- Enable_Overflow_Check --
3242 ---------------------------
3244 procedure Enable_Overflow_Check
(N
: Node_Id
) is
3245 Typ
: constant Entity_Id
:= Base_Type
(Etype
(N
));
3254 if Debug_Flag_CC
then
3255 w
("Enable_Overflow_Check for node ", Int
(N
));
3256 Write_Str
(" Source location = ");
3261 -- Nothing to do if the range of the result is known OK. We skip
3262 -- this for conversions, since the caller already did the check,
3263 -- and in any case the condition for deleting the check for a
3264 -- type conversion is different in any case.
3266 if Nkind
(N
) /= N_Type_Conversion
then
3267 Determine_Range
(N
, OK
, Lo
, Hi
);
3269 -- Note in the test below that we assume that if a bound of the
3270 -- range is equal to that of the type. That's not quite accurate
3271 -- but we do this for the following reasons:
3273 -- a) The way that Determine_Range works, it will typically report
3274 -- the bounds of the value as being equal to the bounds of the
3275 -- type, because it either can't tell anything more precise, or
3276 -- does not think it is worth the effort to be more precise.
3278 -- b) It is very unusual to have a situation in which this would
3279 -- generate an unnecessary overflow check (an example would be
3280 -- a subtype with a range 0 .. Integer'Last - 1 to which the
3281 -- literal value one is added.
3283 -- c) The alternative is a lot of special casing in this routine
3284 -- which would partially duplicate Determine_Range processing.
3287 and then Lo
> Expr_Value
(Type_Low_Bound
(Typ
))
3288 and then Hi
< Expr_Value
(Type_High_Bound
(Typ
))
3290 if Debug_Flag_CC
then
3291 w
("No overflow check required");
3298 -- If not in optimizing mode, set flag and we are done. We are also
3299 -- done (and just set the flag) if the type is not a discrete type,
3300 -- since it is not worth the effort to eliminate checks for other
3301 -- than discrete types. In addition, we take this same path if we
3302 -- have stored the maximum number of checks possible already (a
3303 -- very unlikely situation, but we do not want to blow up!)
3305 if Optimization_Level
= 0
3306 or else not Is_Discrete_Type
(Etype
(N
))
3307 or else Num_Saved_Checks
= Saved_Checks
'Last
3309 Set_Do_Overflow_Check
(N
, True);
3311 if Debug_Flag_CC
then
3312 w
("Optimization off");
3318 -- Otherwise evaluate and check the expression
3323 Target_Type
=> Empty
,
3329 if Debug_Flag_CC
then
3330 w
("Called Find_Check");
3334 w
(" Check_Num = ", Chk
);
3335 w
(" Ent = ", Int
(Ent
));
3336 Write_Str
(" Ofs = ");
3341 -- If check is not of form to optimize, then set flag and we are done
3344 Set_Do_Overflow_Check
(N
, True);
3348 -- If check is already performed, then return without setting flag
3351 if Debug_Flag_CC
then
3352 w
("Check suppressed!");
3358 -- Here we will make a new entry for the new check
3360 Set_Do_Overflow_Check
(N
, True);
3361 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
3362 Saved_Checks
(Num_Saved_Checks
) :=
3367 Target_Type
=> Empty
);
3369 if Debug_Flag_CC
then
3370 w
("Make new entry, check number = ", Num_Saved_Checks
);
3371 w
(" Entity = ", Int
(Ent
));
3372 Write_Str
(" Offset = ");
3374 w
(" Check_Type = O");
3375 w
(" Target_Type = Empty");
3378 -- If we get an exception, then something went wrong, probably because
3379 -- of an error in the structure of the tree due to an incorrect program.
3380 -- Or it may be a bug in the optimization circuit. In either case the
3381 -- safest thing is simply to set the check flag unconditionally.
3385 Set_Do_Overflow_Check
(N
, True);
3387 if Debug_Flag_CC
then
3388 w
(" exception occurred, overflow flag set");
3392 end Enable_Overflow_Check
;
3394 ------------------------
3395 -- Enable_Range_Check --
3396 ------------------------
3398 procedure Enable_Range_Check
(N
: Node_Id
) is
3407 -- Return if unchecked type conversion with range check killed.
3408 -- In this case we never set the flag (that's what Kill_Range_Check
3411 if Nkind
(N
) = N_Unchecked_Type_Conversion
3412 and then Kill_Range_Check
(N
)
3417 -- Debug trace output
3419 if Debug_Flag_CC
then
3420 w
("Enable_Range_Check for node ", Int
(N
));
3421 Write_Str
(" Source location = ");
3426 -- If not in optimizing mode, set flag and we are done. We are also
3427 -- done (and just set the flag) if the type is not a discrete type,
3428 -- since it is not worth the effort to eliminate checks for other
3429 -- than discrete types. In addition, we take this same path if we
3430 -- have stored the maximum number of checks possible already (a
3431 -- very unlikely situation, but we do not want to blow up!)
3433 if Optimization_Level
= 0
3434 or else No
(Etype
(N
))
3435 or else not Is_Discrete_Type
(Etype
(N
))
3436 or else Num_Saved_Checks
= Saved_Checks
'Last
3438 Set_Do_Range_Check
(N
, True);
3440 if Debug_Flag_CC
then
3441 w
("Optimization off");
3447 -- Otherwise find out the target type
3451 -- For assignment, use left side subtype
3453 if Nkind
(P
) = N_Assignment_Statement
3454 and then Expression
(P
) = N
3456 Ttyp
:= Etype
(Name
(P
));
3458 -- For indexed component, use subscript subtype
3460 elsif Nkind
(P
) = N_Indexed_Component
then
3467 Atyp
:= Etype
(Prefix
(P
));
3469 if Is_Access_Type
(Atyp
) then
3470 Atyp
:= Designated_Type
(Atyp
);
3472 -- If the prefix is an access to an unconstrained array,
3473 -- perform check unconditionally: it depends on the bounds
3474 -- of an object and we cannot currently recognize whether
3475 -- the test may be redundant.
3477 if not Is_Constrained
(Atyp
) then
3478 Set_Do_Range_Check
(N
, True);
3483 Indx
:= First_Index
(Atyp
);
3484 Subs
:= First
(Expressions
(P
));
3487 Ttyp
:= Etype
(Indx
);
3496 -- For now, ignore all other cases, they are not so interesting
3499 if Debug_Flag_CC
then
3500 w
(" target type not found, flag set");
3503 Set_Do_Range_Check
(N
, True);
3507 -- Evaluate and check the expression
3512 Target_Type
=> Ttyp
,
3518 if Debug_Flag_CC
then
3519 w
("Called Find_Check");
3520 w
("Target_Typ = ", Int
(Ttyp
));
3524 w
(" Check_Num = ", Chk
);
3525 w
(" Ent = ", Int
(Ent
));
3526 Write_Str
(" Ofs = ");
3531 -- If check is not of form to optimize, then set flag and we are done
3534 if Debug_Flag_CC
then
3535 w
(" expression not of optimizable type, flag set");
3538 Set_Do_Range_Check
(N
, True);
3542 -- If check is already performed, then return without setting flag
3545 if Debug_Flag_CC
then
3546 w
("Check suppressed!");
3552 -- Here we will make a new entry for the new check
3554 Set_Do_Range_Check
(N
, True);
3555 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
3556 Saved_Checks
(Num_Saved_Checks
) :=
3561 Target_Type
=> Ttyp
);
3563 if Debug_Flag_CC
then
3564 w
("Make new entry, check number = ", Num_Saved_Checks
);
3565 w
(" Entity = ", Int
(Ent
));
3566 Write_Str
(" Offset = ");
3568 w
(" Check_Type = R");
3569 w
(" Target_Type = ", Int
(Ttyp
));
3573 -- If we get an exception, then something went wrong, probably because
3574 -- of an error in the structure of the tree due to an incorrect program.
3575 -- Or it may be a bug in the optimization circuit. In either case the
3576 -- safest thing is simply to set the check flag unconditionally.
3580 Set_Do_Range_Check
(N
, True);
3582 if Debug_Flag_CC
then
3583 w
(" exception occurred, range flag set");
3587 end Enable_Range_Check
;
3593 procedure Ensure_Valid
(Expr
: Node_Id
; Holes_OK
: Boolean := False) is
3594 Typ
: constant Entity_Id
:= Etype
(Expr
);
3597 -- Ignore call if we are not doing any validity checking
3599 if not Validity_Checks_On
then
3602 -- Ignore call if range checks suppressed on entity in question
3604 elsif Is_Entity_Name
(Expr
)
3605 and then Range_Checks_Suppressed
(Entity
(Expr
))
3609 -- No check required if expression is from the expander, we assume
3610 -- the expander will generate whatever checks are needed. Note that
3611 -- this is not just an optimization, it avoids infinite recursions!
3613 -- Unchecked conversions must be checked, unless they are initialized
3614 -- scalar values, as in a component assignment in an init proc.
3616 -- In addition, we force a check if Force_Validity_Checks is set
3618 elsif not Comes_From_Source
(Expr
)
3619 and then not Force_Validity_Checks
3620 and then (Nkind
(Expr
) /= N_Unchecked_Type_Conversion
3621 or else Kill_Range_Check
(Expr
))
3625 -- No check required if expression is known to have valid value
3627 elsif Expr_Known_Valid
(Expr
) then
3630 -- No check required if checks off
3632 elsif Range_Checks_Suppressed
(Typ
) then
3635 -- Ignore case of enumeration with holes where the flag is set not
3636 -- to worry about holes, since no special validity check is needed
3638 elsif Is_Enumeration_Type
(Typ
)
3639 and then Has_Non_Standard_Rep
(Typ
)
3644 -- No check required on the left-hand side of an assignment
3646 elsif Nkind
(Parent
(Expr
)) = N_Assignment_Statement
3647 and then Expr
= Name
(Parent
(Expr
))
3651 -- An annoying special case. If this is an out parameter of a scalar
3652 -- type, then the value is not going to be accessed, therefore it is
3653 -- inappropriate to do any validity check at the call site.
3656 -- Only need to worry about scalar types
3658 if Is_Scalar_Type
(Typ
) then
3668 -- Find actual argument (which may be a parameter association)
3669 -- and the parent of the actual argument (the call statement)
3674 if Nkind
(P
) = N_Parameter_Association
then
3679 -- Only need to worry if we are argument of a procedure
3680 -- call since functions don't have out parameters. If this
3681 -- is an indirect or dispatching call, get signature from
3682 -- the subprogram type.
3684 if Nkind
(P
) = N_Procedure_Call_Statement
then
3685 L
:= Parameter_Associations
(P
);
3687 if Is_Entity_Name
(Name
(P
)) then
3688 E
:= Entity
(Name
(P
));
3690 pragma Assert
(Nkind
(Name
(P
)) = N_Explicit_Dereference
);
3691 E
:= Etype
(Name
(P
));
3694 -- Only need to worry if there are indeed actuals, and
3695 -- if this could be a procedure call, otherwise we cannot
3696 -- get a match (either we are not an argument, or the
3697 -- mode of the formal is not OUT). This test also filters
3698 -- out the generic case.
3700 if Is_Non_Empty_List
(L
)
3701 and then Is_Subprogram
(E
)
3703 -- This is the loop through parameters, looking to
3704 -- see if there is an OUT parameter for which we are
3707 F
:= First_Formal
(E
);
3710 while Present
(F
) loop
3711 if Ekind
(F
) = E_Out_Parameter
and then A
= N
then
3724 -- If we fall through, a validity check is required. Note that it would
3725 -- not be good to set Do_Range_Check, even in contexts where this is
3726 -- permissible, since this flag causes checking against the target type,
3727 -- not the source type in contexts such as assignments
3729 Insert_Valid_Check
(Expr
);
3732 ----------------------
3733 -- Expr_Known_Valid --
3734 ----------------------
3736 function Expr_Known_Valid
(Expr
: Node_Id
) return Boolean is
3737 Typ
: constant Entity_Id
:= Etype
(Expr
);
3740 -- Non-scalar types are always considered valid, since they never
3741 -- give rise to the issues of erroneous or bounded error behavior
3742 -- that are the concern. In formal reference manual terms the
3743 -- notion of validity only applies to scalar types. Note that
3744 -- even when packed arrays are represented using modular types,
3745 -- they are still arrays semantically, so they are also always
3746 -- valid (in particular, the unused bits can be random rubbish
3747 -- without affecting the validity of the array value).
3749 if not Is_Scalar_Type
(Typ
) or else Is_Packed_Array_Type
(Typ
) then
3752 -- If no validity checking, then everything is considered valid
3754 elsif not Validity_Checks_On
then
3757 -- Floating-point types are considered valid unless floating-point
3758 -- validity checks have been specifically turned on.
3760 elsif Is_Floating_Point_Type
(Typ
)
3761 and then not Validity_Check_Floating_Point
3765 -- If the expression is the value of an object that is known to
3766 -- be valid, then clearly the expression value itself is valid.
3768 elsif Is_Entity_Name
(Expr
)
3769 and then Is_Known_Valid
(Entity
(Expr
))
3773 -- If the type is one for which all values are known valid, then
3774 -- we are sure that the value is valid except in the slightly odd
3775 -- case where the expression is a reference to a variable whose size
3776 -- has been explicitly set to a value greater than the object size.
3778 elsif Is_Known_Valid
(Typ
) then
3779 if Is_Entity_Name
(Expr
)
3780 and then Ekind
(Entity
(Expr
)) = E_Variable
3781 and then Esize
(Entity
(Expr
)) > Esize
(Typ
)
3788 -- Integer and character literals always have valid values, where
3789 -- appropriate these will be range checked in any case.
3791 elsif Nkind
(Expr
) = N_Integer_Literal
3793 Nkind
(Expr
) = N_Character_Literal
3797 -- If we have a type conversion or a qualification of a known valid
3798 -- value, then the result will always be valid.
3800 elsif Nkind
(Expr
) = N_Type_Conversion
3802 Nkind
(Expr
) = N_Qualified_Expression
3804 return Expr_Known_Valid
(Expression
(Expr
));
3806 -- The result of any function call or operator is always considered
3807 -- valid, since we assume the necessary checks are done by the call.
3808 -- For operators on floating-point operations, we must also check
3809 -- when the operation is the right-hand side of an assignment, or
3810 -- is an actual in a call.
3813 Nkind
(Expr
) in N_Binary_Op
or else Nkind
(Expr
) in N_Unary_Op
3815 if Is_Floating_Point_Type
(Typ
)
3816 and then Validity_Check_Floating_Point
3818 (Nkind
(Parent
(Expr
)) = N_Assignment_Statement
3819 or else Nkind
(Parent
(Expr
)) = N_Function_Call
3820 or else Nkind
(Parent
(Expr
)) = N_Parameter_Association
)
3827 elsif Nkind
(Expr
) = N_Function_Call
then
3830 -- For all other cases, we do not know the expression is valid
3835 end Expr_Known_Valid
;
3841 procedure Find_Check
3843 Check_Type
: Character;
3844 Target_Type
: Entity_Id
;
3845 Entry_OK
: out Boolean;
3846 Check_Num
: out Nat
;
3847 Ent
: out Entity_Id
;
3850 function Within_Range_Of
3851 (Target_Type
: Entity_Id
;
3852 Check_Type
: Entity_Id
) return Boolean;
3853 -- Given a requirement for checking a range against Target_Type, and
3854 -- and a range Check_Type against which a check has already been made,
3855 -- determines if the check against check type is sufficient to ensure
3856 -- that no check against Target_Type is required.
3858 ---------------------
3859 -- Within_Range_Of --
3860 ---------------------
3862 function Within_Range_Of
3863 (Target_Type
: Entity_Id
;
3864 Check_Type
: Entity_Id
) return Boolean
3867 if Target_Type
= Check_Type
then
3872 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Type
);
3873 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Type
);
3874 Clo
: constant Node_Id
:= Type_Low_Bound
(Check_Type
);
3875 Chi
: constant Node_Id
:= Type_High_Bound
(Check_Type
);
3879 or else (Compile_Time_Known_Value
(Tlo
)
3881 Compile_Time_Known_Value
(Clo
)
3883 Expr_Value
(Clo
) >= Expr_Value
(Tlo
)))
3886 or else (Compile_Time_Known_Value
(Thi
)
3888 Compile_Time_Known_Value
(Chi
)
3890 Expr_Value
(Chi
) <= Expr_Value
(Clo
)))
3898 end Within_Range_Of
;
3900 -- Start of processing for Find_Check
3903 -- Establish default, to avoid warnings from GCC
3907 -- Case of expression is simple entity reference
3909 if Is_Entity_Name
(Expr
) then
3910 Ent
:= Entity
(Expr
);
3913 -- Case of expression is entity + known constant
3915 elsif Nkind
(Expr
) = N_Op_Add
3916 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
3917 and then Is_Entity_Name
(Left_Opnd
(Expr
))
3919 Ent
:= Entity
(Left_Opnd
(Expr
));
3920 Ofs
:= Expr_Value
(Right_Opnd
(Expr
));
3922 -- Case of expression is entity - known constant
3924 elsif Nkind
(Expr
) = N_Op_Subtract
3925 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
3926 and then Is_Entity_Name
(Left_Opnd
(Expr
))
3928 Ent
:= Entity
(Left_Opnd
(Expr
));
3929 Ofs
:= UI_Negate
(Expr_Value
(Right_Opnd
(Expr
)));
3931 -- Any other expression is not of the right form
3940 -- Come here with expression of appropriate form, check if
3941 -- entity is an appropriate one for our purposes.
3943 if (Ekind
(Ent
) = E_Variable
3945 Ekind
(Ent
) = E_Constant
3947 Ekind
(Ent
) = E_Loop_Parameter
3949 Ekind
(Ent
) = E_In_Parameter
)
3950 and then not Is_Library_Level_Entity
(Ent
)
3958 -- See if there is matching check already
3960 for J
in reverse 1 .. Num_Saved_Checks
loop
3962 SC
: Saved_Check
renames Saved_Checks
(J
);
3965 if SC
.Killed
= False
3966 and then SC
.Entity
= Ent
3967 and then SC
.Offset
= Ofs
3968 and then SC
.Check_Type
= Check_Type
3969 and then Within_Range_Of
(Target_Type
, SC
.Target_Type
)
3977 -- If we fall through entry was not found
3983 ---------------------------------
3984 -- Generate_Discriminant_Check --
3985 ---------------------------------
3987 -- Note: the code for this procedure is derived from the
3988 -- emit_discriminant_check routine a-trans.c v1.659.
3990 procedure Generate_Discriminant_Check
(N
: Node_Id
) is
3991 Loc
: constant Source_Ptr
:= Sloc
(N
);
3992 Pref
: constant Node_Id
:= Prefix
(N
);
3993 Sel
: constant Node_Id
:= Selector_Name
(N
);
3995 Orig_Comp
: constant Entity_Id
:=
3996 Original_Record_Component
(Entity
(Sel
));
3997 -- The original component to be checked
3999 Discr_Fct
: constant Entity_Id
:=
4000 Discriminant_Checking_Func
(Orig_Comp
);
4001 -- The discriminant checking function
4004 -- One discriminant to be checked in the type
4006 Real_Discr
: Entity_Id
;
4007 -- Actual discriminant in the call
4009 Pref_Type
: Entity_Id
;
4010 -- Type of relevant prefix (ignoring private/access stuff)
4013 -- List of arguments for function call
4016 -- Keep track of the formal corresponding to the actual we build
4017 -- for each discriminant, in order to be able to perform the
4018 -- necessary type conversions.
4021 -- Selected component reference for checking function argument
4024 Pref_Type
:= Etype
(Pref
);
4026 -- Force evaluation of the prefix, so that it does not get evaluated
4027 -- twice (once for the check, once for the actual reference). Such a
4028 -- double evaluation is always a potential source of inefficiency,
4029 -- and is functionally incorrect in the volatile case, or when the
4030 -- prefix may have side-effects. An entity or a component of an
4031 -- entity requires no evaluation.
4033 if Is_Entity_Name
(Pref
) then
4034 if Treat_As_Volatile
(Entity
(Pref
)) then
4035 Force_Evaluation
(Pref
, Name_Req
=> True);
4038 elsif Treat_As_Volatile
(Etype
(Pref
)) then
4039 Force_Evaluation
(Pref
, Name_Req
=> True);
4041 elsif Nkind
(Pref
) = N_Selected_Component
4042 and then Is_Entity_Name
(Prefix
(Pref
))
4047 Force_Evaluation
(Pref
, Name_Req
=> True);
4050 -- For a tagged type, use the scope of the original component to
4051 -- obtain the type, because ???
4053 if Is_Tagged_Type
(Scope
(Orig_Comp
)) then
4054 Pref_Type
:= Scope
(Orig_Comp
);
4056 -- For an untagged derived type, use the discriminants of the
4057 -- parent which have been renamed in the derivation, possibly
4058 -- by a one-to-many discriminant constraint.
4059 -- For non-tagged type, initially get the Etype of the prefix
4062 if Is_Derived_Type
(Pref_Type
)
4063 and then Number_Discriminants
(Pref_Type
) /=
4064 Number_Discriminants
(Etype
(Base_Type
(Pref_Type
)))
4066 Pref_Type
:= Etype
(Base_Type
(Pref_Type
));
4070 -- We definitely should have a checking function, This routine should
4071 -- not be called if no discriminant checking function is present.
4073 pragma Assert
(Present
(Discr_Fct
));
4075 -- Create the list of the actual parameters for the call. This list
4076 -- is the list of the discriminant fields of the record expression to
4077 -- be discriminant checked.
4080 Formal
:= First_Formal
(Discr_Fct
);
4081 Discr
:= First_Discriminant
(Pref_Type
);
4082 while Present
(Discr
) loop
4084 -- If we have a corresponding discriminant field, and a parent
4085 -- subtype is present, then we want to use the corresponding
4086 -- discriminant since this is the one with the useful value.
4088 if Present
(Corresponding_Discriminant
(Discr
))
4089 and then Ekind
(Pref_Type
) = E_Record_Type
4090 and then Present
(Parent_Subtype
(Pref_Type
))
4092 Real_Discr
:= Corresponding_Discriminant
(Discr
);
4094 Real_Discr
:= Discr
;
4097 -- Construct the reference to the discriminant
4100 Make_Selected_Component
(Loc
,
4102 Unchecked_Convert_To
(Pref_Type
,
4103 Duplicate_Subexpr
(Pref
)),
4104 Selector_Name
=> New_Occurrence_Of
(Real_Discr
, Loc
));
4106 -- Manually analyze and resolve this selected component. We really
4107 -- want it just as it appears above, and do not want the expander
4108 -- playing discriminal games etc with this reference. Then we
4109 -- append the argument to the list we are gathering.
4111 Set_Etype
(Scomp
, Etype
(Real_Discr
));
4112 Set_Analyzed
(Scomp
, True);
4113 Append_To
(Args
, Convert_To
(Etype
(Formal
), Scomp
));
4115 Next_Formal_With_Extras
(Formal
);
4116 Next_Discriminant
(Discr
);
4119 -- Now build and insert the call
4122 Make_Raise_Constraint_Error
(Loc
,
4124 Make_Function_Call
(Loc
,
4125 Name
=> New_Occurrence_Of
(Discr_Fct
, Loc
),
4126 Parameter_Associations
=> Args
),
4127 Reason
=> CE_Discriminant_Check_Failed
));
4128 end Generate_Discriminant_Check
;
4130 ---------------------------
4131 -- Generate_Index_Checks --
4132 ---------------------------
4134 procedure Generate_Index_Checks
(N
: Node_Id
) is
4135 Loc
: constant Source_Ptr
:= Sloc
(N
);
4136 A
: constant Node_Id
:= Prefix
(N
);
4142 Sub
:= First
(Expressions
(N
));
4144 while Present
(Sub
) loop
4145 if Do_Range_Check
(Sub
) then
4146 Set_Do_Range_Check
(Sub
, False);
4148 -- Force evaluation except for the case of a simple name of
4149 -- a non-volatile entity.
4151 if not Is_Entity_Name
(Sub
)
4152 or else Treat_As_Volatile
(Entity
(Sub
))
4154 Force_Evaluation
(Sub
);
4157 -- Generate a raise of constraint error with the appropriate
4158 -- reason and a condition of the form:
4160 -- Base_Type(Sub) not in array'range (subscript)
4162 -- Note that the reason we generate the conversion to the
4163 -- base type here is that we definitely want the range check
4164 -- to take place, even if it looks like the subtype is OK.
4165 -- Optimization considerations that allow us to omit the
4166 -- check have already been taken into account in the setting
4167 -- of the Do_Range_Check flag earlier on.
4172 Num
:= New_List
(Make_Integer_Literal
(Loc
, Ind
));
4176 Make_Raise_Constraint_Error
(Loc
,
4180 Convert_To
(Base_Type
(Etype
(Sub
)),
4181 Duplicate_Subexpr_Move_Checks
(Sub
)),
4183 Make_Attribute_Reference
(Loc
,
4184 Prefix
=> Duplicate_Subexpr_Move_Checks
(A
),
4185 Attribute_Name
=> Name_Range
,
4186 Expressions
=> Num
)),
4187 Reason
=> CE_Index_Check_Failed
));
4193 end Generate_Index_Checks
;
4195 --------------------------
4196 -- Generate_Range_Check --
4197 --------------------------
4199 procedure Generate_Range_Check
4201 Target_Type
: Entity_Id
;
4202 Reason
: RT_Exception_Code
)
4204 Loc
: constant Source_Ptr
:= Sloc
(N
);
4205 Source_Type
: constant Entity_Id
:= Etype
(N
);
4206 Source_Base_Type
: constant Entity_Id
:= Base_Type
(Source_Type
);
4207 Target_Base_Type
: constant Entity_Id
:= Base_Type
(Target_Type
);
4210 -- First special case, if the source type is already within the
4211 -- range of the target type, then no check is needed (probably we
4212 -- should have stopped Do_Range_Check from being set in the first
4213 -- place, but better late than later in preventing junk code!
4215 -- We do NOT apply this if the source node is a literal, since in
4216 -- this case the literal has already been labeled as having the
4217 -- subtype of the target.
4219 if In_Subrange_Of
(Source_Type
, Target_Type
)
4221 (Nkind
(N
) = N_Integer_Literal
4223 Nkind
(N
) = N_Real_Literal
4225 Nkind
(N
) = N_Character_Literal
4228 and then Ekind
(Entity
(N
)) = E_Enumeration_Literal
))
4233 -- We need a check, so force evaluation of the node, so that it does
4234 -- not get evaluated twice (once for the check, once for the actual
4235 -- reference). Such a double evaluation is always a potential source
4236 -- of inefficiency, and is functionally incorrect in the volatile case.
4238 if not Is_Entity_Name
(N
)
4239 or else Treat_As_Volatile
(Entity
(N
))
4241 Force_Evaluation
(N
);
4244 -- The easiest case is when Source_Base_Type and Target_Base_Type
4245 -- are the same since in this case we can simply do a direct
4246 -- check of the value of N against the bounds of Target_Type.
4248 -- [constraint_error when N not in Target_Type]
4250 -- Note: this is by far the most common case, for example all cases of
4251 -- checks on the RHS of assignments are in this category, but not all
4252 -- cases are like this. Notably conversions can involve two types.
4254 if Source_Base_Type
= Target_Base_Type
then
4256 Make_Raise_Constraint_Error
(Loc
,
4259 Left_Opnd
=> Duplicate_Subexpr
(N
),
4260 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
4263 -- Next test for the case where the target type is within the bounds
4264 -- of the base type of the source type, since in this case we can
4265 -- simply convert these bounds to the base type of T to do the test.
4267 -- [constraint_error when N not in
4268 -- Source_Base_Type (Target_Type'First)
4270 -- Source_Base_Type(Target_Type'Last))]
4272 -- The conversions will always work and need no check
4274 elsif In_Subrange_Of
(Target_Type
, Source_Base_Type
) then
4276 Make_Raise_Constraint_Error
(Loc
,
4279 Left_Opnd
=> Duplicate_Subexpr
(N
),
4284 Convert_To
(Source_Base_Type
,
4285 Make_Attribute_Reference
(Loc
,
4287 New_Occurrence_Of
(Target_Type
, Loc
),
4288 Attribute_Name
=> Name_First
)),
4291 Convert_To
(Source_Base_Type
,
4292 Make_Attribute_Reference
(Loc
,
4294 New_Occurrence_Of
(Target_Type
, Loc
),
4295 Attribute_Name
=> Name_Last
)))),
4298 -- Note that at this stage we now that the Target_Base_Type is
4299 -- not in the range of the Source_Base_Type (since even the
4300 -- Target_Type itself is not in this range). It could still be
4301 -- the case that the Source_Type is in range of the target base
4302 -- type, since we have not checked that case.
4304 -- If that is the case, we can freely convert the source to the
4305 -- target, and then test the target result against the bounds.
4307 elsif In_Subrange_Of
(Source_Type
, Target_Base_Type
) then
4309 -- We make a temporary to hold the value of the converted
4310 -- value (converted to the base type), and then we will
4311 -- do the test against this temporary.
4313 -- Tnn : constant Target_Base_Type := Target_Base_Type (N);
4314 -- [constraint_error when Tnn not in Target_Type]
4316 -- Then the conversion itself is replaced by an occurrence of Tnn
4319 Tnn
: constant Entity_Id
:=
4320 Make_Defining_Identifier
(Loc
,
4321 Chars
=> New_Internal_Name
('T'));
4324 Insert_Actions
(N
, New_List
(
4325 Make_Object_Declaration
(Loc
,
4326 Defining_Identifier
=> Tnn
,
4327 Object_Definition
=>
4328 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4329 Constant_Present
=> True,
4331 Make_Type_Conversion
(Loc
,
4332 Subtype_Mark
=> New_Occurrence_Of
(Target_Base_Type
, Loc
),
4333 Expression
=> Duplicate_Subexpr
(N
))),
4335 Make_Raise_Constraint_Error
(Loc
,
4338 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
4339 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
4341 Reason
=> Reason
)));
4343 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
4346 -- At this stage, we know that we have two scalar types, which are
4347 -- directly convertible, and where neither scalar type has a base
4348 -- range that is in the range of the other scalar type.
4350 -- The only way this can happen is with a signed and unsigned type.
4351 -- So test for these two cases:
4354 -- Case of the source is unsigned and the target is signed
4356 if Is_Unsigned_Type
(Source_Base_Type
)
4357 and then not Is_Unsigned_Type
(Target_Base_Type
)
4359 -- If the source is unsigned and the target is signed, then we
4360 -- know that the source is not shorter than the target (otherwise
4361 -- the source base type would be in the target base type range).
4363 -- In other words, the unsigned type is either the same size
4364 -- as the target, or it is larger. It cannot be smaller.
4367 (Esize
(Source_Base_Type
) >= Esize
(Target_Base_Type
));
4369 -- We only need to check the low bound if the low bound of the
4370 -- target type is non-negative. If the low bound of the target
4371 -- type is negative, then we know that we will fit fine.
4373 -- If the high bound of the target type is negative, then we
4374 -- know we have a constraint error, since we can't possibly
4375 -- have a negative source.
4377 -- With these two checks out of the way, we can do the check
4378 -- using the source type safely
4380 -- This is definitely the most annoying case!
4382 -- [constraint_error
4383 -- when (Target_Type'First >= 0
4385 -- N < Source_Base_Type (Target_Type'First))
4386 -- or else Target_Type'Last < 0
4387 -- or else N > Source_Base_Type (Target_Type'Last)];
4389 -- We turn off all checks since we know that the conversions
4390 -- will work fine, given the guards for negative values.
4393 Make_Raise_Constraint_Error
(Loc
,
4399 Left_Opnd
=> Make_Op_Ge
(Loc
,
4401 Make_Attribute_Reference
(Loc
,
4403 New_Occurrence_Of
(Target_Type
, Loc
),
4404 Attribute_Name
=> Name_First
),
4405 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
4409 Left_Opnd
=> Duplicate_Subexpr
(N
),
4411 Convert_To
(Source_Base_Type
,
4412 Make_Attribute_Reference
(Loc
,
4414 New_Occurrence_Of
(Target_Type
, Loc
),
4415 Attribute_Name
=> Name_First
)))),
4420 Make_Attribute_Reference
(Loc
,
4421 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
4422 Attribute_Name
=> Name_Last
),
4423 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
))),
4427 Left_Opnd
=> Duplicate_Subexpr
(N
),
4429 Convert_To
(Source_Base_Type
,
4430 Make_Attribute_Reference
(Loc
,
4431 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
4432 Attribute_Name
=> Name_Last
)))),
4435 Suppress
=> All_Checks
);
4437 -- Only remaining possibility is that the source is signed and
4438 -- the target is unsigned
4441 pragma Assert
(not Is_Unsigned_Type
(Source_Base_Type
)
4442 and then Is_Unsigned_Type
(Target_Base_Type
));
4444 -- If the source is signed and the target is unsigned, then
4445 -- we know that the target is not shorter than the source
4446 -- (otherwise the target base type would be in the source
4447 -- base type range).
4449 -- In other words, the unsigned type is either the same size
4450 -- as the target, or it is larger. It cannot be smaller.
4452 -- Clearly we have an error if the source value is negative
4453 -- since no unsigned type can have negative values. If the
4454 -- source type is non-negative, then the check can be done
4455 -- using the target type.
4457 -- Tnn : constant Target_Base_Type (N) := Target_Type;
4459 -- [constraint_error
4460 -- when N < 0 or else Tnn not in Target_Type];
4462 -- We turn off all checks for the conversion of N to the
4463 -- target base type, since we generate the explicit check
4464 -- to ensure that the value is non-negative
4467 Tnn
: constant Entity_Id
:=
4468 Make_Defining_Identifier
(Loc
,
4469 Chars
=> New_Internal_Name
('T'));
4472 Insert_Actions
(N
, New_List
(
4473 Make_Object_Declaration
(Loc
,
4474 Defining_Identifier
=> Tnn
,
4475 Object_Definition
=>
4476 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4477 Constant_Present
=> True,
4479 Make_Type_Conversion
(Loc
,
4481 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4482 Expression
=> Duplicate_Subexpr
(N
))),
4484 Make_Raise_Constraint_Error
(Loc
,
4489 Left_Opnd
=> Duplicate_Subexpr
(N
),
4490 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
4494 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
4496 New_Occurrence_Of
(Target_Type
, Loc
))),
4499 Suppress
=> All_Checks
);
4501 -- Set the Etype explicitly, because Insert_Actions may
4502 -- have placed the declaration in the freeze list for an
4503 -- enclosing construct, and thus it is not analyzed yet.
4505 Set_Etype
(Tnn
, Target_Base_Type
);
4506 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
4510 end Generate_Range_Check
;
4512 ---------------------
4513 -- Get_Discriminal --
4514 ---------------------
4516 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
is
4517 Loc
: constant Source_Ptr
:= Sloc
(E
);
4522 -- The entity E is the type of a private component of the protected
4523 -- type, or the type of a renaming of that component within a protected
4524 -- operation of that type.
4528 if Ekind
(Sc
) /= E_Protected_Type
then
4531 if Ekind
(Sc
) /= E_Protected_Type
then
4536 D
:= First_Discriminant
(Sc
);
4539 and then Chars
(D
) /= Chars
(Bound
)
4541 Next_Discriminant
(D
);
4544 return New_Occurrence_Of
(Discriminal
(D
), Loc
);
4545 end Get_Discriminal
;
4551 function Guard_Access
4554 Ck_Node
: Node_Id
) return Node_Id
4557 if Nkind
(Cond
) = N_Or_Else
then
4558 Set_Paren_Count
(Cond
, 1);
4561 if Nkind
(Ck_Node
) = N_Allocator
then
4568 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
4569 Right_Opnd
=> Make_Null
(Loc
)),
4570 Right_Opnd
=> Cond
);
4574 -----------------------------
4575 -- Index_Checks_Suppressed --
4576 -----------------------------
4578 function Index_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4580 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4581 return Is_Check_Suppressed
(E
, Index_Check
);
4583 return Scope_Suppress
(Index_Check
);
4585 end Index_Checks_Suppressed
;
4591 procedure Initialize
is
4593 for J
in Determine_Range_Cache_N
'Range loop
4594 Determine_Range_Cache_N
(J
) := Empty
;
4598 -------------------------
4599 -- Insert_Range_Checks --
4600 -------------------------
4602 procedure Insert_Range_Checks
4603 (Checks
: Check_Result
;
4605 Suppress_Typ
: Entity_Id
;
4606 Static_Sloc
: Source_Ptr
:= No_Location
;
4607 Flag_Node
: Node_Id
:= Empty
;
4608 Do_Before
: Boolean := False)
4610 Internal_Flag_Node
: Node_Id
:= Flag_Node
;
4611 Internal_Static_Sloc
: Source_Ptr
:= Static_Sloc
;
4613 Check_Node
: Node_Id
;
4614 Checks_On
: constant Boolean :=
4615 (not Index_Checks_Suppressed
(Suppress_Typ
))
4617 (not Range_Checks_Suppressed
(Suppress_Typ
));
4620 -- For now we just return if Checks_On is false, however this should
4621 -- be enhanced to check for an always True value in the condition
4622 -- and to generate a compilation warning???
4624 if not Expander_Active
or else not Checks_On
then
4628 if Static_Sloc
= No_Location
then
4629 Internal_Static_Sloc
:= Sloc
(Node
);
4632 if No
(Flag_Node
) then
4633 Internal_Flag_Node
:= Node
;
4636 for J
in 1 .. 2 loop
4637 exit when No
(Checks
(J
));
4639 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
4640 and then Present
(Condition
(Checks
(J
)))
4642 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
4643 Check_Node
:= Checks
(J
);
4644 Mark_Rewrite_Insertion
(Check_Node
);
4647 Insert_Before_And_Analyze
(Node
, Check_Node
);
4649 Insert_After_And_Analyze
(Node
, Check_Node
);
4652 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
4657 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
4658 Reason
=> CE_Range_Check_Failed
);
4659 Mark_Rewrite_Insertion
(Check_Node
);
4662 Insert_Before_And_Analyze
(Node
, Check_Node
);
4664 Insert_After_And_Analyze
(Node
, Check_Node
);
4668 end Insert_Range_Checks
;
4670 ------------------------
4671 -- Insert_Valid_Check --
4672 ------------------------
4674 procedure Insert_Valid_Check
(Expr
: Node_Id
) is
4675 Loc
: constant Source_Ptr
:= Sloc
(Expr
);
4679 -- Do not insert if checks off, or if not checking validity
4681 if Range_Checks_Suppressed
(Etype
(Expr
))
4682 or else (not Validity_Checks_On
)
4687 -- If we have a checked conversion, then validity check applies to
4688 -- the expression inside the conversion, not the result, since if
4689 -- the expression inside is valid, then so is the conversion result.
4692 while Nkind
(Exp
) = N_Type_Conversion
loop
4693 Exp
:= Expression
(Exp
);
4696 -- Insert the validity check. Note that we do this with validity
4697 -- checks turned off, to avoid recursion, we do not want validity
4698 -- checks on the validity checking code itself!
4700 Validity_Checks_On
:= False;
4703 Make_Raise_Constraint_Error
(Loc
,
4707 Make_Attribute_Reference
(Loc
,
4709 Duplicate_Subexpr_No_Checks
(Exp
, Name_Req
=> True),
4710 Attribute_Name
=> Name_Valid
)),
4711 Reason
=> CE_Invalid_Data
),
4712 Suppress
=> All_Checks
);
4713 Validity_Checks_On
:= True;
4714 end Insert_Valid_Check
;
4716 ----------------------------------
4717 -- Install_Null_Excluding_Check --
4718 ----------------------------------
4720 procedure Install_Null_Excluding_Check
(N
: Node_Id
) is
4721 Loc
: constant Source_Ptr
:= Sloc
(N
);
4722 Etyp
: constant Entity_Id
:= Etype
(N
);
4725 pragma Assert
(Is_Access_Type
(Etyp
));
4727 -- Don't need access check if: 1) we are analyzing a generic, 2) it is
4728 -- known to be non-null, or 3) the check was suppressed on the type
4731 or else Access_Checks_Suppressed
(Etyp
)
4735 -- Otherwise install access check
4739 Make_Raise_Constraint_Error
(Loc
,
4742 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(N
),
4743 Right_Opnd
=> Make_Null
(Loc
)),
4744 Reason
=> CE_Access_Check_Failed
));
4746 end Install_Null_Excluding_Check
;
4748 --------------------------
4749 -- Install_Static_Check --
4750 --------------------------
4752 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
) is
4753 Stat
: constant Boolean := Is_Static_Expression
(R_Cno
);
4754 Typ
: constant Entity_Id
:= Etype
(R_Cno
);
4758 Make_Raise_Constraint_Error
(Loc
,
4759 Reason
=> CE_Range_Check_Failed
));
4760 Set_Analyzed
(R_Cno
);
4761 Set_Etype
(R_Cno
, Typ
);
4762 Set_Raises_Constraint_Error
(R_Cno
);
4763 Set_Is_Static_Expression
(R_Cno
, Stat
);
4764 end Install_Static_Check
;
4766 ---------------------
4767 -- Kill_All_Checks --
4768 ---------------------
4770 procedure Kill_All_Checks
is
4772 if Debug_Flag_CC
then
4773 w
("Kill_All_Checks");
4776 -- We reset the number of saved checks to zero, and also modify
4777 -- all stack entries for statement ranges to indicate that the
4778 -- number of checks at each level is now zero.
4780 Num_Saved_Checks
:= 0;
4782 for J
in 1 .. Saved_Checks_TOS
loop
4783 Saved_Checks_Stack
(J
) := 0;
4785 end Kill_All_Checks
;
4791 procedure Kill_Checks
(V
: Entity_Id
) is
4793 if Debug_Flag_CC
then
4794 w
("Kill_Checks for entity", Int
(V
));
4797 for J
in 1 .. Num_Saved_Checks
loop
4798 if Saved_Checks
(J
).Entity
= V
then
4799 if Debug_Flag_CC
then
4800 w
(" Checks killed for saved check ", J
);
4803 Saved_Checks
(J
).Killed
:= True;
4808 ------------------------------
4809 -- Length_Checks_Suppressed --
4810 ------------------------------
4812 function Length_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4814 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4815 return Is_Check_Suppressed
(E
, Length_Check
);
4817 return Scope_Suppress
(Length_Check
);
4819 end Length_Checks_Suppressed
;
4821 --------------------------------
4822 -- Overflow_Checks_Suppressed --
4823 --------------------------------
4825 function Overflow_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4827 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4828 return Is_Check_Suppressed
(E
, Overflow_Check
);
4830 return Scope_Suppress
(Overflow_Check
);
4832 end Overflow_Checks_Suppressed
;
4838 function Range_Check
4840 Target_Typ
: Entity_Id
;
4841 Source_Typ
: Entity_Id
:= Empty
;
4842 Warn_Node
: Node_Id
:= Empty
) return Check_Result
4845 return Selected_Range_Checks
4846 (Ck_Node
, Target_Typ
, Source_Typ
, Warn_Node
);
4849 -----------------------------
4850 -- Range_Checks_Suppressed --
4851 -----------------------------
4853 function Range_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4857 -- Note: for now we always suppress range checks on Vax float types,
4858 -- since Gigi does not know how to generate these checks.
4860 if Vax_Float
(E
) then
4862 elsif Kill_Range_Checks
(E
) then
4864 elsif Checks_May_Be_Suppressed
(E
) then
4865 return Is_Check_Suppressed
(E
, Range_Check
);
4869 return Scope_Suppress
(Range_Check
);
4870 end Range_Checks_Suppressed
;
4876 procedure Remove_Checks
(Expr
: Node_Id
) is
4877 Discard
: Traverse_Result
;
4878 pragma Warnings
(Off
, Discard
);
4880 function Process
(N
: Node_Id
) return Traverse_Result
;
4881 -- Process a single node during the traversal
4883 function Traverse
is new Traverse_Func
(Process
);
4884 -- The traversal function itself
4890 function Process
(N
: Node_Id
) return Traverse_Result
is
4892 if Nkind
(N
) not in N_Subexpr
then
4896 Set_Do_Range_Check
(N
, False);
4900 Discard
:= Traverse
(Left_Opnd
(N
));
4903 when N_Attribute_Reference
=>
4904 Set_Do_Overflow_Check
(N
, False);
4906 when N_Function_Call
=>
4907 Set_Do_Tag_Check
(N
, False);
4910 Set_Do_Overflow_Check
(N
, False);
4914 Set_Do_Division_Check
(N
, False);
4917 Set_Do_Length_Check
(N
, False);
4920 Set_Do_Division_Check
(N
, False);
4923 Set_Do_Length_Check
(N
, False);
4926 Set_Do_Division_Check
(N
, False);
4929 Set_Do_Length_Check
(N
, False);
4936 Discard
:= Traverse
(Left_Opnd
(N
));
4939 when N_Selected_Component
=>
4940 Set_Do_Discriminant_Check
(N
, False);
4942 when N_Type_Conversion
=>
4943 Set_Do_Length_Check
(N
, False);
4944 Set_Do_Tag_Check
(N
, False);
4945 Set_Do_Overflow_Check
(N
, False);
4954 -- Start of processing for Remove_Checks
4957 Discard
:= Traverse
(Expr
);
4960 ----------------------------
4961 -- Selected_Length_Checks --
4962 ----------------------------
4964 function Selected_Length_Checks
4966 Target_Typ
: Entity_Id
;
4967 Source_Typ
: Entity_Id
;
4968 Warn_Node
: Node_Id
) return Check_Result
4970 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
4973 Expr_Actual
: Node_Id
;
4975 Cond
: Node_Id
:= Empty
;
4976 Do_Access
: Boolean := False;
4977 Wnode
: Node_Id
:= Warn_Node
;
4978 Ret_Result
: Check_Result
:= (Empty
, Empty
);
4979 Num_Checks
: Natural := 0;
4981 procedure Add_Check
(N
: Node_Id
);
4982 -- Adds the action given to Ret_Result if N is non-Empty
4984 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
;
4985 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
4986 -- Comments required ???
4988 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean;
4989 -- True for equal literals and for nodes that denote the same constant
4990 -- entity, even if its value is not a static constant. This includes the
4991 -- case of a discriminal reference within an init proc. Removes some
4992 -- obviously superfluous checks.
4994 function Length_E_Cond
4995 (Exptyp
: Entity_Id
;
4997 Indx
: Nat
) return Node_Id
;
4998 -- Returns expression to compute:
4999 -- Typ'Length /= Exptyp'Length
5001 function Length_N_Cond
5004 Indx
: Nat
) return Node_Id
;
5005 -- Returns expression to compute:
5006 -- Typ'Length /= Expr'Length
5012 procedure Add_Check
(N
: Node_Id
) is
5016 -- For now, ignore attempt to place more than 2 checks ???
5018 if Num_Checks
= 2 then
5022 pragma Assert
(Num_Checks
<= 1);
5023 Num_Checks
:= Num_Checks
+ 1;
5024 Ret_Result
(Num_Checks
) := N
;
5032 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
is
5033 Pt
: constant Entity_Id
:= Scope
(Scope
(E
));
5035 E1
: Entity_Id
:= E
;
5038 if Ekind
(Scope
(E
)) = E_Record_Type
5039 and then Has_Discriminants
(Scope
(E
))
5041 N
:= Build_Discriminal_Subtype_Of_Component
(E
);
5044 Insert_Action
(Ck_Node
, N
);
5045 E1
:= Defining_Identifier
(N
);
5049 if Ekind
(E1
) = E_String_Literal_Subtype
then
5051 Make_Integer_Literal
(Loc
,
5052 Intval
=> String_Literal_Length
(E1
));
5054 elsif Ekind
(Pt
) = E_Protected_Type
5055 and then Has_Discriminants
(Pt
)
5056 and then Has_Completion
(Pt
)
5057 and then not Inside_Init_Proc
5060 -- If the type whose length is needed is a private component
5061 -- constrained by a discriminant, we must expand the 'Length
5062 -- attribute into an explicit computation, using the discriminal
5063 -- of the current protected operation. This is because the actual
5064 -- type of the prival is constructed after the protected opera-
5065 -- tion has been fully expanded.
5068 Indx_Type
: Node_Id
;
5071 Do_Expand
: Boolean := False;
5074 Indx_Type
:= First_Index
(E
);
5076 for J
in 1 .. Indx
- 1 loop
5077 Next_Index
(Indx_Type
);
5080 Get_Index_Bounds
(Indx_Type
, Lo
, Hi
);
5082 if Nkind
(Lo
) = N_Identifier
5083 and then Ekind
(Entity
(Lo
)) = E_In_Parameter
5085 Lo
:= Get_Discriminal
(E
, Lo
);
5089 if Nkind
(Hi
) = N_Identifier
5090 and then Ekind
(Entity
(Hi
)) = E_In_Parameter
5092 Hi
:= Get_Discriminal
(E
, Hi
);
5097 if not Is_Entity_Name
(Lo
) then
5098 Lo
:= Duplicate_Subexpr_No_Checks
(Lo
);
5101 if not Is_Entity_Name
(Hi
) then
5102 Lo
:= Duplicate_Subexpr_No_Checks
(Hi
);
5108 Make_Op_Subtract
(Loc
,
5112 Right_Opnd
=> Make_Integer_Literal
(Loc
, 1));
5117 Make_Attribute_Reference
(Loc
,
5118 Attribute_Name
=> Name_Length
,
5120 New_Occurrence_Of
(E1
, Loc
));
5123 Set_Expressions
(N
, New_List
(
5124 Make_Integer_Literal
(Loc
, Indx
)));
5133 Make_Attribute_Reference
(Loc
,
5134 Attribute_Name
=> Name_Length
,
5136 New_Occurrence_Of
(E1
, Loc
));
5139 Set_Expressions
(N
, New_List
(
5140 Make_Integer_Literal
(Loc
, Indx
)));
5152 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5155 Make_Attribute_Reference
(Loc
,
5156 Attribute_Name
=> Name_Length
,
5158 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5159 Expressions
=> New_List
(
5160 Make_Integer_Literal
(Loc
, Indx
)));
5168 function Length_E_Cond
5169 (Exptyp
: Entity_Id
;
5171 Indx
: Nat
) return Node_Id
5176 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
5177 Right_Opnd
=> Get_E_Length
(Exptyp
, Indx
));
5185 function Length_N_Cond
5188 Indx
: Nat
) return Node_Id
5193 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
5194 Right_Opnd
=> Get_N_Length
(Expr
, Indx
));
5198 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean is
5201 (Nkind
(L
) = N_Integer_Literal
5202 and then Nkind
(R
) = N_Integer_Literal
5203 and then Intval
(L
) = Intval
(R
))
5207 and then Ekind
(Entity
(L
)) = E_Constant
5208 and then ((Is_Entity_Name
(R
)
5209 and then Entity
(L
) = Entity
(R
))
5211 (Nkind
(R
) = N_Type_Conversion
5212 and then Is_Entity_Name
(Expression
(R
))
5213 and then Entity
(L
) = Entity
(Expression
(R
)))))
5217 and then Ekind
(Entity
(R
)) = E_Constant
5218 and then Nkind
(L
) = N_Type_Conversion
5219 and then Is_Entity_Name
(Expression
(L
))
5220 and then Entity
(R
) = Entity
(Expression
(L
)))
5224 and then Is_Entity_Name
(R
)
5225 and then Entity
(L
) = Entity
(R
)
5226 and then Ekind
(Entity
(L
)) = E_In_Parameter
5227 and then Inside_Init_Proc
);
5230 -- Start of processing for Selected_Length_Checks
5233 if not Expander_Active
then
5237 if Target_Typ
= Any_Type
5238 or else Target_Typ
= Any_Composite
5239 or else Raises_Constraint_Error
(Ck_Node
)
5248 T_Typ
:= Target_Typ
;
5250 if No
(Source_Typ
) then
5251 S_Typ
:= Etype
(Ck_Node
);
5253 S_Typ
:= Source_Typ
;
5256 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
5260 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
5261 S_Typ
:= Designated_Type
(S_Typ
);
5262 T_Typ
:= Designated_Type
(T_Typ
);
5265 -- A simple optimization
5267 if Nkind
(Ck_Node
) = N_Null
then
5272 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
5273 if Is_Constrained
(T_Typ
) then
5275 -- The checking code to be generated will freeze the
5276 -- corresponding array type. However, we must freeze the
5277 -- type now, so that the freeze node does not appear within
5278 -- the generated condional expression, but ahead of it.
5280 Freeze_Before
(Ck_Node
, T_Typ
);
5282 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
5283 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
5285 if Is_Access_Type
(Exptyp
) then
5286 Exptyp
:= Designated_Type
(Exptyp
);
5289 -- String_Literal case. This needs to be handled specially be-
5290 -- cause no index types are available for string literals. The
5291 -- condition is simply:
5293 -- T_Typ'Length = string-literal-length
5295 if Nkind
(Expr_Actual
) = N_String_Literal
5296 and then Ekind
(Etype
(Expr_Actual
)) = E_String_Literal_Subtype
5300 Left_Opnd
=> Get_E_Length
(T_Typ
, 1),
5302 Make_Integer_Literal
(Loc
,
5304 String_Literal_Length
(Etype
(Expr_Actual
))));
5306 -- General array case. Here we have a usable actual subtype for
5307 -- the expression, and the condition is built from the two types
5310 -- T_Typ'Length /= Exptyp'Length or else
5311 -- T_Typ'Length (2) /= Exptyp'Length (2) or else
5312 -- T_Typ'Length (3) /= Exptyp'Length (3) or else
5315 elsif Is_Constrained
(Exptyp
) then
5317 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
5331 -- At the library level, we need to ensure that the
5332 -- type of the object is elaborated before the check
5333 -- itself is emitted. This is only done if the object
5334 -- is in the current compilation unit, otherwise the
5335 -- type is frozen and elaborated in its unit.
5337 if Is_Itype
(Exptyp
)
5339 Ekind
(Cunit_Entity
(Current_Sem_Unit
)) = E_Package
5341 not In_Package_Body
(Cunit_Entity
(Current_Sem_Unit
))
5342 and then In_Open_Scopes
(Scope
(Exptyp
))
5344 Ref_Node
:= Make_Itype_Reference
(Sloc
(Ck_Node
));
5345 Set_Itype
(Ref_Node
, Exptyp
);
5346 Insert_Action
(Ck_Node
, Ref_Node
);
5349 L_Index
:= First_Index
(T_Typ
);
5350 R_Index
:= First_Index
(Exptyp
);
5352 for Indx
in 1 .. Ndims
loop
5353 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
5355 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
5357 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
5358 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
5360 -- Deal with compile time length check. Note that we
5361 -- skip this in the access case, because the access
5362 -- value may be null, so we cannot know statically.
5365 and then Compile_Time_Known_Value
(L_Low
)
5366 and then Compile_Time_Known_Value
(L_High
)
5367 and then Compile_Time_Known_Value
(R_Low
)
5368 and then Compile_Time_Known_Value
(R_High
)
5370 if Expr_Value
(L_High
) >= Expr_Value
(L_Low
) then
5371 L_Length
:= Expr_Value
(L_High
) -
5372 Expr_Value
(L_Low
) + 1;
5374 L_Length
:= UI_From_Int
(0);
5377 if Expr_Value
(R_High
) >= Expr_Value
(R_Low
) then
5378 R_Length
:= Expr_Value
(R_High
) -
5379 Expr_Value
(R_Low
) + 1;
5381 R_Length
:= UI_From_Int
(0);
5384 if L_Length
> R_Length
then
5386 (Compile_Time_Constraint_Error
5387 (Wnode
, "too few elements for}?", T_Typ
));
5389 elsif L_Length
< R_Length
then
5391 (Compile_Time_Constraint_Error
5392 (Wnode
, "too many elements for}?", T_Typ
));
5395 -- The comparison for an individual index subtype
5396 -- is omitted if the corresponding index subtypes
5397 -- statically match, since the result is known to
5398 -- be true. Note that this test is worth while even
5399 -- though we do static evaluation, because non-static
5400 -- subtypes can statically match.
5403 Subtypes_Statically_Match
5404 (Etype
(L_Index
), Etype
(R_Index
))
5407 (Same_Bounds
(L_Low
, R_Low
)
5408 and then Same_Bounds
(L_High
, R_High
))
5411 (Cond
, Length_E_Cond
(Exptyp
, T_Typ
, Indx
));
5420 -- Handle cases where we do not get a usable actual subtype that
5421 -- is constrained. This happens for example in the function call
5422 -- and explicit dereference cases. In these cases, we have to get
5423 -- the length or range from the expression itself, making sure we
5424 -- do not evaluate it more than once.
5426 -- Here Ck_Node is the original expression, or more properly the
5427 -- result of applying Duplicate_Expr to the original tree,
5428 -- forcing the result to be a name.
5432 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
5435 -- Build the condition for the explicit dereference case
5437 for Indx
in 1 .. Ndims
loop
5439 (Cond
, Length_N_Cond
(Ck_Node
, T_Typ
, Indx
));
5446 -- Construct the test and insert into the tree
5448 if Present
(Cond
) then
5450 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
5454 (Make_Raise_Constraint_Error
(Loc
,
5456 Reason
=> CE_Length_Check_Failed
));
5460 end Selected_Length_Checks
;
5462 ---------------------------
5463 -- Selected_Range_Checks --
5464 ---------------------------
5466 function Selected_Range_Checks
5468 Target_Typ
: Entity_Id
;
5469 Source_Typ
: Entity_Id
;
5470 Warn_Node
: Node_Id
) return Check_Result
5472 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
5475 Expr_Actual
: Node_Id
;
5477 Cond
: Node_Id
:= Empty
;
5478 Do_Access
: Boolean := False;
5479 Wnode
: Node_Id
:= Warn_Node
;
5480 Ret_Result
: Check_Result
:= (Empty
, Empty
);
5481 Num_Checks
: Integer := 0;
5483 procedure Add_Check
(N
: Node_Id
);
5484 -- Adds the action given to Ret_Result if N is non-Empty
5486 function Discrete_Range_Cond
5488 Typ
: Entity_Id
) return Node_Id
;
5489 -- Returns expression to compute:
5490 -- Low_Bound (Expr) < Typ'First
5492 -- High_Bound (Expr) > Typ'Last
5494 function Discrete_Expr_Cond
5496 Typ
: Entity_Id
) return Node_Id
;
5497 -- Returns expression to compute:
5502 function Get_E_First_Or_Last
5505 Nam
: Name_Id
) return Node_Id
;
5506 -- Returns expression to compute:
5507 -- E'First or E'Last
5509 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5510 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5511 -- Returns expression to compute:
5512 -- N'First or N'Last using Duplicate_Subexpr_No_Checks
5514 function Range_E_Cond
5515 (Exptyp
: Entity_Id
;
5519 -- Returns expression to compute:
5520 -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
5522 function Range_Equal_E_Cond
5523 (Exptyp
: Entity_Id
;
5525 Indx
: Nat
) return Node_Id
;
5526 -- Returns expression to compute:
5527 -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
5529 function Range_N_Cond
5532 Indx
: Nat
) return Node_Id
;
5533 -- Return expression to compute:
5534 -- Expr'First < Typ'First or else Expr'Last > Typ'Last
5540 procedure Add_Check
(N
: Node_Id
) is
5544 -- For now, ignore attempt to place more than 2 checks ???
5546 if Num_Checks
= 2 then
5550 pragma Assert
(Num_Checks
<= 1);
5551 Num_Checks
:= Num_Checks
+ 1;
5552 Ret_Result
(Num_Checks
) := N
;
5556 -------------------------
5557 -- Discrete_Expr_Cond --
5558 -------------------------
5560 function Discrete_Expr_Cond
5562 Typ
: Entity_Id
) return Node_Id
5570 Convert_To
(Base_Type
(Typ
),
5571 Duplicate_Subexpr_No_Checks
(Expr
)),
5573 Convert_To
(Base_Type
(Typ
),
5574 Get_E_First_Or_Last
(Typ
, 0, Name_First
))),
5579 Convert_To
(Base_Type
(Typ
),
5580 Duplicate_Subexpr_No_Checks
(Expr
)),
5584 Get_E_First_Or_Last
(Typ
, 0, Name_Last
))));
5585 end Discrete_Expr_Cond
;
5587 -------------------------
5588 -- Discrete_Range_Cond --
5589 -------------------------
5591 function Discrete_Range_Cond
5593 Typ
: Entity_Id
) return Node_Id
5595 LB
: Node_Id
:= Low_Bound
(Expr
);
5596 HB
: Node_Id
:= High_Bound
(Expr
);
5598 Left_Opnd
: Node_Id
;
5599 Right_Opnd
: Node_Id
;
5602 if Nkind
(LB
) = N_Identifier
5603 and then Ekind
(Entity
(LB
)) = E_Discriminant
then
5604 LB
:= New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
5607 if Nkind
(HB
) = N_Identifier
5608 and then Ekind
(Entity
(HB
)) = E_Discriminant
then
5609 HB
:= New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
5616 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(LB
)),
5620 (Base_Type
(Typ
), Get_E_First_Or_Last
(Typ
, 0, Name_First
)));
5622 if Base_Type
(Typ
) = Typ
then
5625 elsif Compile_Time_Known_Value
(High_Bound
(Scalar_Range
(Typ
)))
5627 Compile_Time_Known_Value
(High_Bound
(Scalar_Range
5630 if Is_Floating_Point_Type
(Typ
) then
5631 if Expr_Value_R
(High_Bound
(Scalar_Range
(Typ
))) =
5632 Expr_Value_R
(High_Bound
(Scalar_Range
(Base_Type
(Typ
))))
5638 if Expr_Value
(High_Bound
(Scalar_Range
(Typ
))) =
5639 Expr_Value
(High_Bound
(Scalar_Range
(Base_Type
(Typ
))))
5650 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(HB
)),
5655 Get_E_First_Or_Last
(Typ
, 0, Name_Last
)));
5657 return Make_Or_Else
(Loc
, Left_Opnd
, Right_Opnd
);
5658 end Discrete_Range_Cond
;
5660 -------------------------
5661 -- Get_E_First_Or_Last --
5662 -------------------------
5664 function Get_E_First_Or_Last
5667 Nam
: Name_Id
) return Node_Id
5675 if Is_Array_Type
(E
) then
5676 N
:= First_Index
(E
);
5678 for J
in 2 .. Indx
loop
5683 N
:= Scalar_Range
(E
);
5686 if Nkind
(N
) = N_Subtype_Indication
then
5687 LB
:= Low_Bound
(Range_Expression
(Constraint
(N
)));
5688 HB
:= High_Bound
(Range_Expression
(Constraint
(N
)));
5690 elsif Is_Entity_Name
(N
) then
5691 LB
:= Type_Low_Bound
(Etype
(N
));
5692 HB
:= Type_High_Bound
(Etype
(N
));
5695 LB
:= Low_Bound
(N
);
5696 HB
:= High_Bound
(N
);
5699 if Nam
= Name_First
then
5705 if Nkind
(Bound
) = N_Identifier
5706 and then Ekind
(Entity
(Bound
)) = E_Discriminant
5708 -- If this is a task discriminant, and we are the body, we must
5709 -- retrieve the corresponding body discriminal. This is another
5710 -- consequence of the early creation of discriminals, and the
5711 -- need to generate constraint checks before their declarations
5712 -- are made visible.
5714 if Is_Concurrent_Record_Type
(Scope
(Entity
(Bound
))) then
5716 Tsk
: constant Entity_Id
:=
5717 Corresponding_Concurrent_Type
5718 (Scope
(Entity
(Bound
)));
5722 if In_Open_Scopes
(Tsk
)
5723 and then Has_Completion
(Tsk
)
5725 -- Find discriminant of original task, and use its
5726 -- current discriminal, which is the renaming within
5729 Disc
:= First_Discriminant
(Tsk
);
5730 while Present
(Disc
) loop
5731 if Chars
(Disc
) = Chars
(Entity
(Bound
)) then
5732 Set_Scope
(Discriminal
(Disc
), Tsk
);
5733 return New_Occurrence_Of
(Discriminal
(Disc
), Loc
);
5736 Next_Discriminant
(Disc
);
5739 -- That loop should always succeed in finding a matching
5740 -- entry and returning. Fatal error if not.
5742 raise Program_Error
;
5746 New_Occurrence_Of
(Discriminal
(Entity
(Bound
)), Loc
);
5750 return New_Occurrence_Of
(Discriminal
(Entity
(Bound
)), Loc
);
5753 elsif Nkind
(Bound
) = N_Identifier
5754 and then Ekind
(Entity
(Bound
)) = E_In_Parameter
5755 and then not Inside_Init_Proc
5757 return Get_Discriminal
(E
, Bound
);
5759 elsif Nkind
(Bound
) = N_Integer_Literal
then
5760 return Make_Integer_Literal
(Loc
, Intval
(Bound
));
5763 return Duplicate_Subexpr_No_Checks
(Bound
);
5765 end Get_E_First_Or_Last
;
5771 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5774 Make_Attribute_Reference
(Loc
,
5775 Attribute_Name
=> Name_First
,
5777 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5778 Expressions
=> New_List
(
5779 Make_Integer_Literal
(Loc
, Indx
)));
5786 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5789 Make_Attribute_Reference
(Loc
,
5790 Attribute_Name
=> Name_Last
,
5792 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5793 Expressions
=> New_List
(
5794 Make_Integer_Literal
(Loc
, Indx
)));
5801 function Range_E_Cond
5802 (Exptyp
: Entity_Id
;
5804 Indx
: Nat
) return Node_Id
5811 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_First
),
5812 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5816 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_Last
),
5817 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5821 ------------------------
5822 -- Range_Equal_E_Cond --
5823 ------------------------
5825 function Range_Equal_E_Cond
5826 (Exptyp
: Entity_Id
;
5828 Indx
: Nat
) return Node_Id
5835 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_First
),
5836 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5839 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_Last
),
5840 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5841 end Range_Equal_E_Cond
;
5847 function Range_N_Cond
5850 Indx
: Nat
) return Node_Id
5857 Left_Opnd
=> Get_N_First
(Expr
, Indx
),
5858 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5862 Left_Opnd
=> Get_N_Last
(Expr
, Indx
),
5863 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5866 -- Start of processing for Selected_Range_Checks
5869 if not Expander_Active
then
5873 if Target_Typ
= Any_Type
5874 or else Target_Typ
= Any_Composite
5875 or else Raises_Constraint_Error
(Ck_Node
)
5884 T_Typ
:= Target_Typ
;
5886 if No
(Source_Typ
) then
5887 S_Typ
:= Etype
(Ck_Node
);
5889 S_Typ
:= Source_Typ
;
5892 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
5896 -- The order of evaluating T_Typ before S_Typ seems to be critical
5897 -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
5898 -- in, and since Node can be an N_Range node, it might be invalid.
5899 -- Should there be an assert check somewhere for taking the Etype of
5900 -- an N_Range node ???
5902 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
5903 S_Typ
:= Designated_Type
(S_Typ
);
5904 T_Typ
:= Designated_Type
(T_Typ
);
5907 -- A simple optimization
5909 if Nkind
(Ck_Node
) = N_Null
then
5914 -- For an N_Range Node, check for a null range and then if not
5915 -- null generate a range check action.
5917 if Nkind
(Ck_Node
) = N_Range
then
5919 -- There's no point in checking a range against itself
5921 if Ck_Node
= Scalar_Range
(T_Typ
) then
5926 T_LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
5927 T_HB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
5928 LB
: constant Node_Id
:= Low_Bound
(Ck_Node
);
5929 HB
: constant Node_Id
:= High_Bound
(Ck_Node
);
5930 Null_Range
: Boolean;
5932 Out_Of_Range_L
: Boolean;
5933 Out_Of_Range_H
: Boolean;
5936 -- Check for case where everything is static and we can
5937 -- do the check at compile time. This is skipped if we
5938 -- have an access type, since the access value may be null.
5940 -- ??? This code can be improved since you only need to know
5941 -- that the two respective bounds (LB & T_LB or HB & T_HB)
5942 -- are known at compile time to emit pertinent messages.
5944 if Compile_Time_Known_Value
(LB
)
5945 and then Compile_Time_Known_Value
(HB
)
5946 and then Compile_Time_Known_Value
(T_LB
)
5947 and then Compile_Time_Known_Value
(T_HB
)
5948 and then not Do_Access
5950 -- Floating-point case
5952 if Is_Floating_Point_Type
(S_Typ
) then
5953 Null_Range
:= Expr_Value_R
(HB
) < Expr_Value_R
(LB
);
5955 (Expr_Value_R
(LB
) < Expr_Value_R
(T_LB
))
5957 (Expr_Value_R
(LB
) > Expr_Value_R
(T_HB
));
5960 (Expr_Value_R
(HB
) > Expr_Value_R
(T_HB
))
5962 (Expr_Value_R
(HB
) < Expr_Value_R
(T_LB
));
5964 -- Fixed or discrete type case
5967 Null_Range
:= Expr_Value
(HB
) < Expr_Value
(LB
);
5969 (Expr_Value
(LB
) < Expr_Value
(T_LB
))
5971 (Expr_Value
(LB
) > Expr_Value
(T_HB
));
5974 (Expr_Value
(HB
) > Expr_Value
(T_HB
))
5976 (Expr_Value
(HB
) < Expr_Value
(T_LB
));
5979 if not Null_Range
then
5980 if Out_Of_Range_L
then
5981 if No
(Warn_Node
) then
5983 (Compile_Time_Constraint_Error
5984 (Low_Bound
(Ck_Node
),
5985 "static value out of range of}?", T_Typ
));
5989 (Compile_Time_Constraint_Error
5991 "static range out of bounds of}?", T_Typ
));
5995 if Out_Of_Range_H
then
5996 if No
(Warn_Node
) then
5998 (Compile_Time_Constraint_Error
5999 (High_Bound
(Ck_Node
),
6000 "static value out of range of}?", T_Typ
));
6004 (Compile_Time_Constraint_Error
6006 "static range out of bounds of}?", T_Typ
));
6014 LB
: Node_Id
:= Low_Bound
(Ck_Node
);
6015 HB
: Node_Id
:= High_Bound
(Ck_Node
);
6019 -- If either bound is a discriminant and we are within
6020 -- the record declaration, it is a use of the discriminant
6021 -- in a constraint of a component, and nothing can be
6022 -- checked here. The check will be emitted within the
6023 -- init proc. Before then, the discriminal has no real
6026 if Nkind
(LB
) = N_Identifier
6027 and then Ekind
(Entity
(LB
)) = E_Discriminant
6029 if Current_Scope
= Scope
(Entity
(LB
)) then
6033 New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
6037 if Nkind
(HB
) = N_Identifier
6038 and then Ekind
(Entity
(HB
)) = E_Discriminant
6040 if Current_Scope
= Scope
(Entity
(HB
)) then
6044 New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
6048 Cond
:= Discrete_Range_Cond
(Ck_Node
, T_Typ
);
6049 Set_Paren_Count
(Cond
, 1);
6055 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(HB
),
6056 Right_Opnd
=> Duplicate_Subexpr_No_Checks
(LB
)),
6057 Right_Opnd
=> Cond
);
6063 elsif Is_Scalar_Type
(S_Typ
) then
6065 -- This somewhat duplicates what Apply_Scalar_Range_Check does,
6066 -- except the above simply sets a flag in the node and lets
6067 -- gigi generate the check base on the Etype of the expression.
6068 -- Sometimes, however we want to do a dynamic check against an
6069 -- arbitrary target type, so we do that here.
6071 if Ekind
(Base_Type
(S_Typ
)) /= Ekind
(Base_Type
(T_Typ
)) then
6072 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6074 -- For literals, we can tell if the constraint error will be
6075 -- raised at compile time, so we never need a dynamic check, but
6076 -- if the exception will be raised, then post the usual warning,
6077 -- and replace the literal with a raise constraint error
6078 -- expression. As usual, skip this for access types
6080 elsif Compile_Time_Known_Value
(Ck_Node
)
6081 and then not Do_Access
6084 LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
6085 UB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
6087 Out_Of_Range
: Boolean;
6088 Static_Bounds
: constant Boolean :=
6089 Compile_Time_Known_Value
(LB
)
6090 and Compile_Time_Known_Value
(UB
);
6093 -- Following range tests should use Sem_Eval routine ???
6095 if Static_Bounds
then
6096 if Is_Floating_Point_Type
(S_Typ
) then
6098 (Expr_Value_R
(Ck_Node
) < Expr_Value_R
(LB
))
6100 (Expr_Value_R
(Ck_Node
) > Expr_Value_R
(UB
));
6102 else -- fixed or discrete type
6104 Expr_Value
(Ck_Node
) < Expr_Value
(LB
)
6106 Expr_Value
(Ck_Node
) > Expr_Value
(UB
);
6109 -- Bounds of the type are static and the literal is
6110 -- out of range so make a warning message.
6112 if Out_Of_Range
then
6113 if No
(Warn_Node
) then
6115 (Compile_Time_Constraint_Error
6117 "static value out of range of}?", T_Typ
));
6121 (Compile_Time_Constraint_Error
6123 "static value out of range of}?", T_Typ
));
6128 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6132 -- Here for the case of a non-static expression, we need a runtime
6133 -- check unless the source type range is guaranteed to be in the
6134 -- range of the target type.
6137 if not In_Subrange_Of
(S_Typ
, T_Typ
) then
6138 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6143 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
6144 if Is_Constrained
(T_Typ
) then
6146 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
6147 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
6149 if Is_Access_Type
(Exptyp
) then
6150 Exptyp
:= Designated_Type
(Exptyp
);
6153 -- String_Literal case. This needs to be handled specially be-
6154 -- cause no index types are available for string literals. The
6155 -- condition is simply:
6157 -- T_Typ'Length = string-literal-length
6159 if Nkind
(Expr_Actual
) = N_String_Literal
then
6162 -- General array case. Here we have a usable actual subtype for
6163 -- the expression, and the condition is built from the two types
6165 -- T_Typ'First < Exptyp'First or else
6166 -- T_Typ'Last > Exptyp'Last or else
6167 -- T_Typ'First(1) < Exptyp'First(1) or else
6168 -- T_Typ'Last(1) > Exptyp'Last(1) or else
6171 elsif Is_Constrained
(Exptyp
) then
6173 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
6183 L_Index
:= First_Index
(T_Typ
);
6184 R_Index
:= First_Index
(Exptyp
);
6186 for Indx
in 1 .. Ndims
loop
6187 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
6189 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
6191 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
6192 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
6194 -- Deal with compile time length check. Note that we
6195 -- skip this in the access case, because the access
6196 -- value may be null, so we cannot know statically.
6199 Subtypes_Statically_Match
6200 (Etype
(L_Index
), Etype
(R_Index
))
6202 -- If the target type is constrained then we
6203 -- have to check for exact equality of bounds
6204 -- (required for qualified expressions).
6206 if Is_Constrained
(T_Typ
) then
6209 Range_Equal_E_Cond
(Exptyp
, T_Typ
, Indx
));
6213 (Cond
, Range_E_Cond
(Exptyp
, T_Typ
, Indx
));
6224 -- Handle cases where we do not get a usable actual subtype that
6225 -- is constrained. This happens for example in the function call
6226 -- and explicit dereference cases. In these cases, we have to get
6227 -- the length or range from the expression itself, making sure we
6228 -- do not evaluate it more than once.
6230 -- Here Ck_Node is the original expression, or more properly the
6231 -- result of applying Duplicate_Expr to the original tree,
6232 -- forcing the result to be a name.
6236 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
6239 -- Build the condition for the explicit dereference case
6241 for Indx
in 1 .. Ndims
loop
6243 (Cond
, Range_N_Cond
(Ck_Node
, T_Typ
, Indx
));
6250 -- Generate an Action to check that the bounds of the
6251 -- source value are within the constraints imposed by the
6252 -- target type for a conversion to an unconstrained type.
6255 if Nkind
(Parent
(Ck_Node
)) = N_Type_Conversion
then
6257 Opnd_Index
: Node_Id
;
6258 Targ_Index
: Node_Id
;
6262 := First_Index
(Get_Actual_Subtype
(Ck_Node
));
6263 Targ_Index
:= First_Index
(T_Typ
);
6265 while Opnd_Index
/= Empty
loop
6266 if Nkind
(Opnd_Index
) = N_Range
then
6268 (Low_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6271 (High_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6275 -- If null range, no check needed
6278 Compile_Time_Known_Value
(High_Bound
(Opnd_Index
))
6280 Compile_Time_Known_Value
(Low_Bound
(Opnd_Index
))
6282 Expr_Value
(High_Bound
(Opnd_Index
)) <
6283 Expr_Value
(Low_Bound
(Opnd_Index
))
6287 elsif Is_Out_Of_Range
6288 (Low_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6291 (High_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6294 (Compile_Time_Constraint_Error
6295 (Wnode
, "value out of range of}?", T_Typ
));
6301 (Opnd_Index
, Etype
(Targ_Index
)));
6305 Next_Index
(Opnd_Index
);
6306 Next_Index
(Targ_Index
);
6313 -- Construct the test and insert into the tree
6315 if Present
(Cond
) then
6317 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
6321 (Make_Raise_Constraint_Error
(Loc
,
6323 Reason
=> CE_Range_Check_Failed
));
6327 end Selected_Range_Checks
;
6329 -------------------------------
6330 -- Storage_Checks_Suppressed --
6331 -------------------------------
6333 function Storage_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6335 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
6336 return Is_Check_Suppressed
(E
, Storage_Check
);
6338 return Scope_Suppress
(Storage_Check
);
6340 end Storage_Checks_Suppressed
;
6342 ---------------------------
6343 -- Tag_Checks_Suppressed --
6344 ---------------------------
6346 function Tag_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6349 if Kill_Tag_Checks
(E
) then
6351 elsif Checks_May_Be_Suppressed
(E
) then
6352 return Is_Check_Suppressed
(E
, Tag_Check
);
6356 return Scope_Suppress
(Tag_Check
);
6357 end Tag_Checks_Suppressed
;