1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2004 Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 with Atree
; use Atree
;
28 with Debug
; use Debug
;
29 with Einfo
; use Einfo
;
30 with Errout
; use Errout
;
31 with Exp_Ch2
; use Exp_Ch2
;
32 with Exp_Util
; use Exp_Util
;
33 with Elists
; use Elists
;
34 with Eval_Fat
; use Eval_Fat
;
35 with Freeze
; use Freeze
;
37 with Nlists
; use Nlists
;
38 with Nmake
; use Nmake
;
40 with Output
; use Output
;
41 with Restrict
; use Restrict
;
42 with Rident
; use Rident
;
43 with Rtsfind
; use Rtsfind
;
45 with Sem_Eval
; use Sem_Eval
;
46 with Sem_Ch3
; use Sem_Ch3
;
47 with Sem_Ch8
; use Sem_Ch8
;
48 with Sem_Res
; use Sem_Res
;
49 with Sem_Util
; use Sem_Util
;
50 with Sem_Warn
; use Sem_Warn
;
51 with Sinfo
; use Sinfo
;
52 with Sinput
; use Sinput
;
53 with Snames
; use Snames
;
54 with Sprint
; use Sprint
;
55 with Stand
; use Stand
;
56 with Targparm
; use Targparm
;
57 with Tbuild
; use Tbuild
;
58 with Ttypes
; use Ttypes
;
59 with Urealp
; use Urealp
;
60 with Validsw
; use Validsw
;
62 package body Checks
is
64 -- General note: many of these routines are concerned with generating
65 -- checking code to make sure that constraint error is raised at runtime.
66 -- Clearly this code is only needed if the expander is active, since
67 -- otherwise we will not be generating code or going into the runtime
70 -- We therefore disconnect most of these checks if the expander is
71 -- inactive. This has the additional benefit that we do not need to
72 -- worry about the tree being messed up by previous errors (since errors
73 -- turn off expansion anyway).
75 -- There are a few exceptions to the above rule. For instance routines
76 -- such as Apply_Scalar_Range_Check that do not insert any code can be
77 -- safely called even when the Expander is inactive (but Errors_Detected
78 -- is 0). The benefit of executing this code when expansion is off, is
79 -- the ability to emit constraint error warning for static expressions
80 -- even when we are not generating code.
82 -------------------------------------
83 -- Suppression of Redundant Checks --
84 -------------------------------------
86 -- This unit implements a limited circuit for removal of redundant
87 -- checks. The processing is based on a tracing of simple sequential
88 -- flow. For any sequence of statements, we save expressions that are
89 -- marked to be checked, and then if the same expression appears later
90 -- with the same check, then under certain circumstances, the second
91 -- check can be suppressed.
93 -- Basically, we can suppress the check if we know for certain that
94 -- the previous expression has been elaborated (together with its
95 -- check), and we know that the exception frame is the same, and that
96 -- nothing has happened to change the result of the exception.
98 -- Let us examine each of these three conditions in turn to describe
99 -- how we ensure that this condition is met.
101 -- First, we need to know for certain that the previous expression has
102 -- been executed. This is done principly by the mechanism of calling
103 -- Conditional_Statements_Begin at the start of any statement sequence
104 -- and Conditional_Statements_End at the end. The End call causes all
105 -- checks remembered since the Begin call to be discarded. This does
106 -- miss a few cases, notably the case of a nested BEGIN-END block with
107 -- no exception handlers. But the important thing is to be conservative.
108 -- The other protection is that all checks are discarded if a label
109 -- is encountered, since then the assumption of sequential execution
110 -- is violated, and we don't know enough about the flow.
112 -- Second, we need to know that the exception frame is the same. We
113 -- do this by killing all remembered checks when we enter a new frame.
114 -- Again, that's over-conservative, but generally the cases we can help
115 -- with are pretty local anyway (like the body of a loop for example).
117 -- Third, we must be sure to forget any checks which are no longer valid.
118 -- This is done by two mechanisms, first the Kill_Checks_Variable call is
119 -- used to note any changes to local variables. We only attempt to deal
120 -- with checks involving local variables, so we do not need to worry
121 -- about global variables. Second, a call to any non-global procedure
122 -- causes us to abandon all stored checks, since such a all may affect
123 -- the values of any local variables.
125 -- The following define the data structures used to deal with remembering
126 -- checks so that redundant checks can be eliminated as described above.
128 -- Right now, the only expressions that we deal with are of the form of
129 -- simple local objects (either declared locally, or IN parameters) or
130 -- such objects plus/minus a compile time known constant. We can do
131 -- more later on if it seems worthwhile, but this catches many simple
132 -- cases in practice.
134 -- The following record type reflects a single saved check. An entry
135 -- is made in the stack of saved checks if and only if the expression
136 -- has been elaborated with the indicated checks.
138 type Saved_Check
is record
140 -- Set True if entry is killed by Kill_Checks
143 -- The entity involved in the expression that is checked
146 -- A compile time value indicating the result of adding or
147 -- subtracting a compile time value. This value is to be
148 -- added to the value of the Entity. A value of zero is
149 -- used for the case of a simple entity reference.
151 Check_Type
: Character;
152 -- This is set to 'R' for a range check (in which case Target_Type
153 -- is set to the target type for the range check) or to 'O' for an
154 -- overflow check (in which case Target_Type is set to Empty).
156 Target_Type
: Entity_Id
;
157 -- Used only if Do_Range_Check is set. Records the target type for
158 -- the check. We need this, because a check is a duplicate only if
159 -- it has a the same target type (or more accurately one with a
160 -- range that is smaller or equal to the stored target type of a
164 -- The following table keeps track of saved checks. Rather than use an
165 -- extensible table. We just use a table of fixed size, and we discard
166 -- any saved checks that do not fit. That's very unlikely to happen and
167 -- this is only an optimization in any case.
169 Saved_Checks
: array (Int
range 1 .. 200) of Saved_Check
;
170 -- Array of saved checks
172 Num_Saved_Checks
: Nat
:= 0;
173 -- Number of saved checks
175 -- The following stack keeps track of statement ranges. It is treated
176 -- as a stack. When Conditional_Statements_Begin is called, an entry
177 -- is pushed onto this stack containing the value of Num_Saved_Checks
178 -- at the time of the call. Then when Conditional_Statements_End is
179 -- called, this value is popped off and used to reset Num_Saved_Checks.
181 -- Note: again, this is a fixed length stack with a size that should
182 -- always be fine. If the value of the stack pointer goes above the
183 -- limit, then we just forget all saved checks.
185 Saved_Checks_Stack
: array (Int
range 1 .. 100) of Nat
;
186 Saved_Checks_TOS
: Nat
:= 0;
188 -----------------------
189 -- Local Subprograms --
190 -----------------------
192 procedure Apply_Float_Conversion_Check
194 Target_Typ
: Entity_Id
);
195 -- The checks on a conversion from a floating-point type to an integer
196 -- type are delicate. They have to be performed before conversion, they
197 -- have to raise an exception when the operand is a NaN, and rounding must
198 -- be taken into account to determine the safe bounds of the operand.
200 procedure Apply_Selected_Length_Checks
202 Target_Typ
: Entity_Id
;
203 Source_Typ
: Entity_Id
;
204 Do_Static
: Boolean);
205 -- This is the subprogram that does all the work for Apply_Length_Check
206 -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as
207 -- described for the above routines. The Do_Static flag indicates that
208 -- only a static check is to be done.
210 procedure Apply_Selected_Range_Checks
212 Target_Typ
: Entity_Id
;
213 Source_Typ
: Entity_Id
;
214 Do_Static
: Boolean);
215 -- This is the subprogram that does all the work for Apply_Range_Check.
216 -- Expr, Target_Typ and Source_Typ are as described for the above
217 -- routine. The Do_Static flag indicates that only a static check is
222 Check_Type
: Character;
223 Target_Type
: Entity_Id
;
224 Entry_OK
: out Boolean;
228 -- This routine is used by Enable_Range_Check and Enable_Overflow_Check
229 -- to see if a check is of the form for optimization, and if so, to see
230 -- if it has already been performed. Expr is the expression to check,
231 -- and Check_Type is 'R' for a range check, 'O' for an overflow check.
232 -- Target_Type is the target type for a range check, and Empty for an
233 -- overflow check. If the entry is not of the form for optimization,
234 -- then Entry_OK is set to False, and the remaining out parameters
235 -- are undefined. If the entry is OK, then Ent/Ofs are set to the
236 -- entity and offset from the expression. Check_Num is the number of
237 -- a matching saved entry in Saved_Checks, or zero if no such entry
240 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
;
241 -- If a discriminal is used in constraining a prival, Return reference
242 -- to the discriminal of the protected body (which renames the parameter
243 -- of the enclosing protected operation). This clumsy transformation is
244 -- needed because privals are created too late and their actual subtypes
245 -- are not available when analysing the bodies of the protected operations.
246 -- To be cleaned up???
248 function Guard_Access
251 Ck_Node
: Node_Id
) return Node_Id
;
252 -- In the access type case, guard the test with a test to ensure
253 -- that the access value is non-null, since the checks do not
254 -- not apply to null access values.
256 procedure Install_Null_Excluding_Check
(N
: Node_Id
);
257 -- Determines whether an access node requires a runtime access check and
258 -- if so inserts the appropriate run-time check
260 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
);
261 -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the
262 -- Constraint_Error node.
264 function Selected_Length_Checks
266 Target_Typ
: Entity_Id
;
267 Source_Typ
: Entity_Id
;
268 Warn_Node
: Node_Id
) return Check_Result
;
269 -- Like Apply_Selected_Length_Checks, except it doesn't modify
270 -- anything, just returns a list of nodes as described in the spec of
271 -- this package for the Range_Check function.
273 function Selected_Range_Checks
275 Target_Typ
: Entity_Id
;
276 Source_Typ
: Entity_Id
;
277 Warn_Node
: Node_Id
) return Check_Result
;
278 -- Like Apply_Selected_Range_Checks, except it doesn't modify anything,
279 -- just returns a list of nodes as described in the spec of this package
280 -- for the Range_Check function.
282 ------------------------------
283 -- Access_Checks_Suppressed --
284 ------------------------------
286 function Access_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
288 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
289 return Is_Check_Suppressed
(E
, Access_Check
);
291 return Scope_Suppress
(Access_Check
);
293 end Access_Checks_Suppressed
;
295 -------------------------------------
296 -- Accessibility_Checks_Suppressed --
297 -------------------------------------
299 function Accessibility_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
301 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
302 return Is_Check_Suppressed
(E
, Accessibility_Check
);
304 return Scope_Suppress
(Accessibility_Check
);
306 end Accessibility_Checks_Suppressed
;
308 -------------------------
309 -- Append_Range_Checks --
310 -------------------------
312 procedure Append_Range_Checks
313 (Checks
: Check_Result
;
315 Suppress_Typ
: Entity_Id
;
316 Static_Sloc
: Source_Ptr
;
319 Internal_Flag_Node
: constant Node_Id
:= Flag_Node
;
320 Internal_Static_Sloc
: constant Source_Ptr
:= Static_Sloc
;
322 Checks_On
: constant Boolean :=
323 (not Index_Checks_Suppressed
(Suppress_Typ
))
325 (not Range_Checks_Suppressed
(Suppress_Typ
));
328 -- For now we just return if Checks_On is false, however this should
329 -- be enhanced to check for an always True value in the condition
330 -- and to generate a compilation warning???
332 if not Checks_On
then
337 exit when No
(Checks
(J
));
339 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
340 and then Present
(Condition
(Checks
(J
)))
342 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
343 Append_To
(Stmts
, Checks
(J
));
344 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
350 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
351 Reason
=> CE_Range_Check_Failed
));
354 end Append_Range_Checks
;
356 ------------------------
357 -- Apply_Access_Check --
358 ------------------------
360 procedure Apply_Access_Check
(N
: Node_Id
) is
361 P
: constant Node_Id
:= Prefix
(N
);
364 if Inside_A_Generic
then
368 if Is_Entity_Name
(P
) then
369 Check_Unset_Reference
(P
);
372 -- We do not need access checks if prefix is known to be non-null
374 if Known_Non_Null
(P
) then
377 -- We do not need access checks if they are suppressed on the type
379 elsif Access_Checks_Suppressed
(Etype
(P
)) then
382 -- We do not need checks if we are not generating code (i.e. the
383 -- expander is not active). This is not just an optimization, there
384 -- are cases (e.g. with pragma Debug) where generating the checks
385 -- can cause real trouble).
387 elsif not Expander_Active
then
391 -- Case where P is an entity name
393 if Is_Entity_Name
(P
) then
395 Ent
: constant Entity_Id
:= Entity
(P
);
398 if Access_Checks_Suppressed
(Ent
) then
402 -- Otherwise we are going to generate an access check, and
403 -- are we have done it, the entity will now be known non null
404 -- But we have to check for safe sequential semantics here!
406 if Safe_To_Capture_Value
(N
, Ent
) then
407 Set_Is_Known_Non_Null
(Ent
);
412 -- Access check is required
414 Install_Null_Excluding_Check
(P
);
415 end Apply_Access_Check
;
417 -------------------------------
418 -- Apply_Accessibility_Check --
419 -------------------------------
421 procedure Apply_Accessibility_Check
(N
: Node_Id
; Typ
: Entity_Id
) is
422 Loc
: constant Source_Ptr
:= Sloc
(N
);
423 Param_Ent
: constant Entity_Id
:= Param_Entity
(N
);
424 Param_Level
: Node_Id
;
425 Type_Level
: Node_Id
;
428 if Inside_A_Generic
then
431 -- Only apply the run-time check if the access parameter
432 -- has an associated extra access level parameter and
433 -- when the level of the type is less deep than the level
434 -- of the access parameter.
436 elsif Present
(Param_Ent
)
437 and then Present
(Extra_Accessibility
(Param_Ent
))
438 and then UI_Gt
(Object_Access_Level
(N
),
439 Type_Access_Level
(Typ
))
440 and then not Accessibility_Checks_Suppressed
(Param_Ent
)
441 and then not Accessibility_Checks_Suppressed
(Typ
)
444 New_Occurrence_Of
(Extra_Accessibility
(Param_Ent
), Loc
);
447 Make_Integer_Literal
(Loc
, Type_Access_Level
(Typ
));
449 -- Raise Program_Error if the accessibility level of the
450 -- the access parameter is deeper than the level of the
451 -- target access type.
454 Make_Raise_Program_Error
(Loc
,
457 Left_Opnd
=> Param_Level
,
458 Right_Opnd
=> Type_Level
),
459 Reason
=> PE_Accessibility_Check_Failed
));
461 Analyze_And_Resolve
(N
);
463 end Apply_Accessibility_Check
;
465 ---------------------------
466 -- Apply_Alignment_Check --
467 ---------------------------
469 procedure Apply_Alignment_Check
(E
: Entity_Id
; N
: Node_Id
) is
470 AC
: constant Node_Id
:= Address_Clause
(E
);
474 Alignment_Required
: constant Boolean := Maximum_Alignment
> 1;
475 -- Constant to show whether target requires alignment checks
478 -- See if check needed. Note that we never need a check if the
479 -- maximum alignment is one, since the check will always succeed
482 or else not Check_Address_Alignment
(AC
)
483 or else not Alignment_Required
489 Expr
:= Expression
(AC
);
491 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
then
492 Expr
:= Expression
(Expr
);
494 elsif Nkind
(Expr
) = N_Function_Call
495 and then Is_Entity_Name
(Name
(Expr
))
496 and then Is_RTE
(Entity
(Name
(Expr
)), RE_To_Address
)
498 Expr
:= First
(Parameter_Associations
(Expr
));
500 if Nkind
(Expr
) = N_Parameter_Association
then
501 Expr
:= Explicit_Actual_Parameter
(Expr
);
505 -- Here Expr is the address value. See if we know that the
506 -- value is unacceptable at compile time.
508 if Compile_Time_Known_Value
(Expr
)
509 and then Known_Alignment
(E
)
511 if Expr_Value
(Expr
) mod Alignment
(E
) /= 0 then
513 Make_Raise_Program_Error
(Loc
,
514 Reason
=> PE_Misaligned_Address_Value
));
516 ("?specified address for& not " &
517 "consistent with alignment ('R'M 13.3(27))", Expr
, E
);
520 -- Here we do not know if the value is acceptable, generate
521 -- code to raise PE if alignment is inappropriate.
524 -- Skip generation of this code if we don't want elab code
526 if not Restriction_Active
(No_Elaboration_Code
) then
527 Insert_After_And_Analyze
(N
,
528 Make_Raise_Program_Error
(Loc
,
535 (RTE
(RE_Integer_Address
),
536 Duplicate_Subexpr_No_Checks
(Expr
)),
538 Make_Attribute_Reference
(Loc
,
539 Prefix
=> New_Occurrence_Of
(E
, Loc
),
540 Attribute_Name
=> Name_Alignment
)),
541 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
542 Reason
=> PE_Misaligned_Address_Value
),
543 Suppress
=> All_Checks
);
550 when RE_Not_Available
=>
552 end Apply_Alignment_Check
;
554 -------------------------------------
555 -- Apply_Arithmetic_Overflow_Check --
556 -------------------------------------
558 -- This routine is called only if the type is an integer type, and
559 -- a software arithmetic overflow check must be performed for op
560 -- (add, subtract, multiply). The check is performed only if
561 -- Software_Overflow_Checking is enabled and Do_Overflow_Check
562 -- is set. In this case we expand the operation into a more complex
563 -- sequence of tests that ensures that overflow is properly caught.
565 procedure Apply_Arithmetic_Overflow_Check
(N
: Node_Id
) is
566 Loc
: constant Source_Ptr
:= Sloc
(N
);
567 Typ
: constant Entity_Id
:= Etype
(N
);
568 Rtyp
: constant Entity_Id
:= Root_Type
(Typ
);
569 Siz
: constant Int
:= UI_To_Int
(Esize
(Rtyp
));
570 Dsiz
: constant Int
:= Siz
* 2;
577 -- Skip this if overflow checks are done in back end, or the overflow
578 -- flag is not set anyway, or we are not doing code expansion.
580 if Backend_Overflow_Checks_On_Target
581 or else not Do_Overflow_Check
(N
)
582 or else not Expander_Active
587 -- Otherwise, we generate the full general code for front end overflow
588 -- detection, which works by doing arithmetic in a larger type:
594 -- Typ (Checktyp (x) op Checktyp (y));
596 -- where Typ is the type of the original expression, and Checktyp is
597 -- an integer type of sufficient length to hold the largest possible
600 -- In the case where check type exceeds the size of Long_Long_Integer,
601 -- we use a different approach, expanding to:
603 -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y)))
605 -- where xxx is Add, Multiply or Subtract as appropriate
607 -- Find check type if one exists
609 if Dsiz
<= Standard_Integer_Size
then
610 Ctyp
:= Standard_Integer
;
612 elsif Dsiz
<= Standard_Long_Long_Integer_Size
then
613 Ctyp
:= Standard_Long_Long_Integer
;
615 -- No check type exists, use runtime call
618 if Nkind
(N
) = N_Op_Add
then
619 Cent
:= RE_Add_With_Ovflo_Check
;
621 elsif Nkind
(N
) = N_Op_Multiply
then
622 Cent
:= RE_Multiply_With_Ovflo_Check
;
625 pragma Assert
(Nkind
(N
) = N_Op_Subtract
);
626 Cent
:= RE_Subtract_With_Ovflo_Check
;
631 Make_Function_Call
(Loc
,
632 Name
=> New_Reference_To
(RTE
(Cent
), Loc
),
633 Parameter_Associations
=> New_List
(
634 OK_Convert_To
(RTE
(RE_Integer_64
), Left_Opnd
(N
)),
635 OK_Convert_To
(RTE
(RE_Integer_64
), Right_Opnd
(N
))))));
637 Analyze_And_Resolve
(N
, Typ
);
641 -- If we fall through, we have the case where we do the arithmetic in
642 -- the next higher type and get the check by conversion. In these cases
643 -- Ctyp is set to the type to be used as the check type.
645 Opnod
:= Relocate_Node
(N
);
647 Opnd
:= OK_Convert_To
(Ctyp
, Left_Opnd
(Opnod
));
650 Set_Etype
(Opnd
, Ctyp
);
651 Set_Analyzed
(Opnd
, True);
652 Set_Left_Opnd
(Opnod
, Opnd
);
654 Opnd
:= OK_Convert_To
(Ctyp
, Right_Opnd
(Opnod
));
657 Set_Etype
(Opnd
, Ctyp
);
658 Set_Analyzed
(Opnd
, True);
659 Set_Right_Opnd
(Opnod
, Opnd
);
661 -- The type of the operation changes to the base type of the check
662 -- type, and we reset the overflow check indication, since clearly
663 -- no overflow is possible now that we are using a double length
664 -- type. We also set the Analyzed flag to avoid a recursive attempt
665 -- to expand the node.
667 Set_Etype
(Opnod
, Base_Type
(Ctyp
));
668 Set_Do_Overflow_Check
(Opnod
, False);
669 Set_Analyzed
(Opnod
, True);
671 -- Now build the outer conversion
673 Opnd
:= OK_Convert_To
(Typ
, Opnod
);
675 Set_Etype
(Opnd
, Typ
);
677 -- In the discrete type case, we directly generate the range check
678 -- for the outer operand. This range check will implement the required
681 if Is_Discrete_Type
(Typ
) then
683 Generate_Range_Check
(Expression
(N
), Typ
, CE_Overflow_Check_Failed
);
685 -- For other types, we enable overflow checking on the conversion,
686 -- after setting the node as analyzed to prevent recursive attempts
687 -- to expand the conversion node.
690 Set_Analyzed
(Opnd
, True);
691 Enable_Overflow_Check
(Opnd
);
696 when RE_Not_Available
=>
698 end Apply_Arithmetic_Overflow_Check
;
700 ----------------------------
701 -- Apply_Array_Size_Check --
702 ----------------------------
704 -- Note: Really of course this entre check should be in the backend,
705 -- and perhaps this is not quite the right value, but it is good
706 -- enough to catch the normal cases (and the relevant ACVC tests!)
708 -- The situation is as follows. In GNAT 3 (GCC 2.x), the size in bits
709 -- is computed in 32 bits without an overflow check. That's a real
710 -- problem for Ada. So what we do in GNAT 3 is to approximate the
711 -- size of an array by manually multiplying the element size by the
712 -- number of elements, and comparing that against the allowed limits.
714 -- In GNAT 5, the size in byte is still computed in 32 bits without
715 -- an overflow check in the dynamic case, but the size in bits is
716 -- computed in 64 bits. We assume that's good enough, so we use the
717 -- size in bits for the test.
719 procedure Apply_Array_Size_Check
(N
: Node_Id
; Typ
: Entity_Id
) is
720 Loc
: constant Source_Ptr
:= Sloc
(N
);
721 Ctyp
: constant Entity_Id
:= Component_Type
(Typ
);
722 Ent
: constant Entity_Id
:= Defining_Identifier
(N
);
734 Static
: Boolean := True;
735 -- Set false if any index subtye bound is non-static
737 Umark
: constant Uintp
.Save_Mark
:= Uintp
.Mark
;
738 -- We can throw away all the Uint computations here, since they are
739 -- done only to generate boolean test results.
742 -- Size to check against
744 function Is_Address_Or_Import
(Decl
: Node_Id
) return Boolean;
745 -- Determines if Decl is an address clause or Import/Interface pragma
746 -- that references the defining identifier of the current declaration.
748 --------------------------
749 -- Is_Address_Or_Import --
750 --------------------------
752 function Is_Address_Or_Import
(Decl
: Node_Id
) return Boolean is
754 if Nkind
(Decl
) = N_At_Clause
then
755 return Chars
(Identifier
(Decl
)) = Chars
(Ent
);
757 elsif Nkind
(Decl
) = N_Attribute_Definition_Clause
then
759 Chars
(Decl
) = Name_Address
761 Nkind
(Name
(Decl
)) = N_Identifier
763 Chars
(Name
(Decl
)) = Chars
(Ent
);
765 elsif Nkind
(Decl
) = N_Pragma
then
766 if (Chars
(Decl
) = Name_Import
768 Chars
(Decl
) = Name_Interface
)
769 and then Present
(Pragma_Argument_Associations
(Decl
))
772 F
: constant Node_Id
:=
773 First
(Pragma_Argument_Associations
(Decl
));
781 Nkind
(Expression
(Next
(F
))) = N_Identifier
783 Chars
(Expression
(Next
(F
))) = Chars
(Ent
);
793 end Is_Address_Or_Import
;
795 -- Start of processing for Apply_Array_Size_Check
798 -- No need for a check if not expanding
800 if not Expander_Active
then
804 -- No need for a check if checks are suppressed
806 if Storage_Checks_Suppressed
(Typ
) then
810 -- It is pointless to insert this check inside an init proc, because
811 -- that's too late, we have already built the object to be the right
812 -- size, and if it's too large, too bad!
814 if Inside_Init_Proc
then
818 -- Look head for pragma interface/import or address clause applying
819 -- to this entity. If found, we suppress the check entirely. For now
820 -- we only look ahead 20 declarations to stop this becoming too slow
821 -- Note that eventually this whole routine gets moved to gigi.
824 for Ctr
in 1 .. 20 loop
828 if Is_Address_Or_Import
(Decl
) then
835 if Opt
.GCC_Version
= 3 then
837 -- No problem if size is known at compile time (even if the front
838 -- end does not know it) because the back end does do overflow
839 -- checking on the size in bytes if it is compile time known.
841 if Size_Known_At_Compile_Time
(Typ
) then
846 -- Following code is temporarily deleted, since GCC 3 is returning
847 -- zero for size in bits of large dynamic arrays. ???
849 -- -- Otherwise we check for the size in bits exceeding 2**31-1 * 8.
850 -- -- This is the case in which we could end up with problems from
851 -- -- an unnoticed overflow in computing the size in bytes
853 -- Check_Siz := (Uint_2 ** 31 - Uint_1) * Uint_8;
856 -- Make_Attribute_Reference (Loc,
857 -- Prefix => New_Occurrence_Of (Typ, Loc),
858 -- Attribute_Name => Name_Size);
860 -- GCC 2 case (for now this is for GCC 3 dynamic case as well)
863 -- First step is to calculate the maximum number of elements. For
864 -- this calculation, we use the actual size of the subtype if it is
865 -- static, and if a bound of a subtype is non-static, we go to the
866 -- bound of the base type.
869 Indx
:= First_Index
(Typ
);
870 while Present
(Indx
) loop
871 Xtyp
:= Etype
(Indx
);
872 Lo
:= Type_Low_Bound
(Xtyp
);
873 Hi
:= Type_High_Bound
(Xtyp
);
875 -- If any bound raises constraint error, we will never get this
876 -- far, so there is no need to generate any kind of check.
878 if Raises_Constraint_Error
(Lo
)
880 Raises_Constraint_Error
(Hi
)
882 Uintp
.Release
(Umark
);
886 -- Otherwise get bounds values
888 if Is_Static_Expression
(Lo
) then
889 Lob
:= Expr_Value
(Lo
);
891 Lob
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Xtyp
)));
895 if Is_Static_Expression
(Hi
) then
896 Hib
:= Expr_Value
(Hi
);
898 Hib
:= Expr_Value
(Type_High_Bound
(Base_Type
(Xtyp
)));
902 Siz
:= Siz
* UI_Max
(Hib
- Lob
+ 1, Uint_0
);
906 -- Compute the limit against which we want to check. For subprograms,
907 -- where the array will go on the stack, we use 8*2**24, which (in
908 -- bits) is the size of a 16 megabyte array.
910 if Is_Subprogram
(Scope
(Ent
)) then
911 Check_Siz
:= Uint_2
** 27;
913 Check_Siz
:= Uint_2
** 31;
916 -- If we have all static bounds and Siz is too large, then we know
917 -- we know we have a storage error right now, so generate message
919 if Static
and then Siz
>= Check_Siz
then
921 Make_Raise_Storage_Error
(Loc
,
922 Reason
=> SE_Object_Too_Large
));
923 Error_Msg_N
("?Storage_Error will be raised at run-time", N
);
924 Uintp
.Release
(Umark
);
928 -- Case of component size known at compile time. If the array
929 -- size is definitely in range, then we do not need a check.
931 if Known_Esize
(Ctyp
)
932 and then Siz
* Esize
(Ctyp
) < Check_Siz
934 Uintp
.Release
(Umark
);
938 -- Here if a dynamic check is required
940 -- What we do is to build an expression for the size of the array,
941 -- which is computed as the 'Size of the array component, times
942 -- the size of each dimension.
944 Uintp
.Release
(Umark
);
947 Make_Attribute_Reference
(Loc
,
948 Prefix
=> New_Occurrence_Of
(Ctyp
, Loc
),
949 Attribute_Name
=> Name_Size
);
951 Indx
:= First_Index
(Typ
);
952 for J
in 1 .. Number_Dimensions
(Typ
) loop
953 if Sloc
(Etype
(Indx
)) = Sloc
(N
) then
954 Ensure_Defined
(Etype
(Indx
), N
);
958 Make_Op_Multiply
(Loc
,
961 Make_Attribute_Reference
(Loc
,
962 Prefix
=> New_Occurrence_Of
(Typ
, Loc
),
963 Attribute_Name
=> Name_Length
,
964 Expressions
=> New_List
(
965 Make_Integer_Literal
(Loc
, J
))));
970 -- Common code to actually emit the check
973 Make_Raise_Storage_Error
(Loc
,
978 Make_Integer_Literal
(Loc
,
979 Intval
=> Check_Siz
)),
980 Reason
=> SE_Object_Too_Large
);
982 Set_Size_Check_Code
(Defining_Identifier
(N
), Code
);
983 Insert_Action
(N
, Code
, Suppress
=> All_Checks
);
984 end Apply_Array_Size_Check
;
986 ----------------------------
987 -- Apply_Constraint_Check --
988 ----------------------------
990 procedure Apply_Constraint_Check
993 No_Sliding
: Boolean := False)
995 Desig_Typ
: Entity_Id
;
998 if Inside_A_Generic
then
1001 elsif Is_Scalar_Type
(Typ
) then
1002 Apply_Scalar_Range_Check
(N
, Typ
);
1004 elsif Is_Array_Type
(Typ
) then
1006 -- A useful optimization: an aggregate with only an Others clause
1007 -- always has the right bounds.
1009 if Nkind
(N
) = N_Aggregate
1010 and then No
(Expressions
(N
))
1012 (First
(Choices
(First
(Component_Associations
(N
)))))
1018 if Is_Constrained
(Typ
) then
1019 Apply_Length_Check
(N
, Typ
);
1022 Apply_Range_Check
(N
, Typ
);
1025 Apply_Range_Check
(N
, Typ
);
1028 elsif (Is_Record_Type
(Typ
)
1029 or else Is_Private_Type
(Typ
))
1030 and then Has_Discriminants
(Base_Type
(Typ
))
1031 and then Is_Constrained
(Typ
)
1033 Apply_Discriminant_Check
(N
, Typ
);
1035 elsif Is_Access_Type
(Typ
) then
1037 Desig_Typ
:= Designated_Type
(Typ
);
1039 -- No checks necessary if expression statically null
1041 if Nkind
(N
) = N_Null
then
1044 -- No sliding possible on access to arrays
1046 elsif Is_Array_Type
(Desig_Typ
) then
1047 if Is_Constrained
(Desig_Typ
) then
1048 Apply_Length_Check
(N
, Typ
);
1051 Apply_Range_Check
(N
, Typ
);
1053 elsif Has_Discriminants
(Base_Type
(Desig_Typ
))
1054 and then Is_Constrained
(Desig_Typ
)
1056 Apply_Discriminant_Check
(N
, Typ
);
1059 if Can_Never_Be_Null
(Typ
)
1060 and then not Can_Never_Be_Null
(Etype
(N
))
1062 Install_Null_Excluding_Check
(N
);
1065 end Apply_Constraint_Check
;
1067 ------------------------------
1068 -- Apply_Discriminant_Check --
1069 ------------------------------
1071 procedure Apply_Discriminant_Check
1074 Lhs
: Node_Id
:= Empty
)
1076 Loc
: constant Source_Ptr
:= Sloc
(N
);
1077 Do_Access
: constant Boolean := Is_Access_Type
(Typ
);
1078 S_Typ
: Entity_Id
:= Etype
(N
);
1082 function Is_Aliased_Unconstrained_Component
return Boolean;
1083 -- It is possible for an aliased component to have a nominal
1084 -- unconstrained subtype (through instantiation). If this is a
1085 -- discriminated component assigned in the expansion of an aggregate
1086 -- in an initialization, the check must be suppressed. This unusual
1087 -- situation requires a predicate of its own (see 7503-008).
1089 ----------------------------------------
1090 -- Is_Aliased_Unconstrained_Component --
1091 ----------------------------------------
1093 function Is_Aliased_Unconstrained_Component
return Boolean is
1098 if Nkind
(Lhs
) /= N_Selected_Component
then
1101 Comp
:= Entity
(Selector_Name
(Lhs
));
1102 Pref
:= Prefix
(Lhs
);
1105 if Ekind
(Comp
) /= E_Component
1106 or else not Is_Aliased
(Comp
)
1111 return not Comes_From_Source
(Pref
)
1112 and then In_Instance
1113 and then not Is_Constrained
(Etype
(Comp
));
1114 end Is_Aliased_Unconstrained_Component
;
1116 -- Start of processing for Apply_Discriminant_Check
1120 T_Typ
:= Designated_Type
(Typ
);
1125 -- Nothing to do if discriminant checks are suppressed or else no code
1126 -- is to be generated
1128 if not Expander_Active
1129 or else Discriminant_Checks_Suppressed
(T_Typ
)
1134 -- No discriminant checks necessary for access when expression
1135 -- is statically Null. This is not only an optimization, this is
1136 -- fundamental because otherwise discriminant checks may be generated
1137 -- in init procs for types containing an access to a non-frozen yet
1138 -- record, causing a deadly forward reference.
1140 -- Also, if the expression is of an access type whose designated
1141 -- type is incomplete, then the access value must be null and
1142 -- we suppress the check.
1144 if Nkind
(N
) = N_Null
then
1147 elsif Is_Access_Type
(S_Typ
) then
1148 S_Typ
:= Designated_Type
(S_Typ
);
1150 if Ekind
(S_Typ
) = E_Incomplete_Type
then
1155 -- If an assignment target is present, then we need to generate
1156 -- the actual subtype if the target is a parameter or aliased
1157 -- object with an unconstrained nominal subtype.
1160 and then (Present
(Param_Entity
(Lhs
))
1161 or else (not Is_Constrained
(T_Typ
)
1162 and then Is_Aliased_View
(Lhs
)
1163 and then not Is_Aliased_Unconstrained_Component
))
1165 T_Typ
:= Get_Actual_Subtype
(Lhs
);
1168 -- Nothing to do if the type is unconstrained (this is the case
1169 -- where the actual subtype in the RM sense of N is unconstrained
1170 -- and no check is required).
1172 if not Is_Constrained
(T_Typ
) then
1176 -- Nothing to do if the type is an Unchecked_Union
1178 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
1182 -- Suppress checks if the subtypes are the same.
1183 -- the check must be preserved in an assignment to a formal, because
1184 -- the constraint is given by the actual.
1186 if Nkind
(Original_Node
(N
)) /= N_Allocator
1188 or else not Is_Entity_Name
(Lhs
)
1189 or else No
(Param_Entity
(Lhs
)))
1192 or else (Do_Access
and then Designated_Type
(Typ
) = S_Typ
))
1193 and then not Is_Aliased_View
(Lhs
)
1198 -- We can also eliminate checks on allocators with a subtype mark
1199 -- that coincides with the context type. The context type may be a
1200 -- subtype without a constraint (common case, a generic actual).
1202 elsif Nkind
(Original_Node
(N
)) = N_Allocator
1203 and then Is_Entity_Name
(Expression
(Original_Node
(N
)))
1206 Alloc_Typ
: constant Entity_Id
:=
1207 Entity
(Expression
(Original_Node
(N
)));
1210 if Alloc_Typ
= T_Typ
1211 or else (Nkind
(Parent
(T_Typ
)) = N_Subtype_Declaration
1212 and then Is_Entity_Name
(
1213 Subtype_Indication
(Parent
(T_Typ
)))
1214 and then Alloc_Typ
= Base_Type
(T_Typ
))
1222 -- See if we have a case where the types are both constrained, and
1223 -- all the constraints are constants. In this case, we can do the
1224 -- check successfully at compile time.
1226 -- We skip this check for the case where the node is a rewritten`
1227 -- allocator, because it already carries the context subtype, and
1228 -- extracting the discriminants from the aggregate is messy.
1230 if Is_Constrained
(S_Typ
)
1231 and then Nkind
(Original_Node
(N
)) /= N_Allocator
1241 -- S_Typ may not have discriminants in the case where it is a
1242 -- private type completed by a default discriminated type. In
1243 -- that case, we need to get the constraints from the
1244 -- underlying_type. If the underlying type is unconstrained (i.e.
1245 -- has no default discriminants) no check is needed.
1247 if Has_Discriminants
(S_Typ
) then
1248 Discr
:= First_Discriminant
(S_Typ
);
1249 DconS
:= First_Elmt
(Discriminant_Constraint
(S_Typ
));
1252 Discr
:= First_Discriminant
(Underlying_Type
(S_Typ
));
1255 (Discriminant_Constraint
(Underlying_Type
(S_Typ
)));
1261 -- A further optimization: if T_Typ is derived from S_Typ
1262 -- without imposing a constraint, no check is needed.
1264 if Nkind
(Original_Node
(Parent
(T_Typ
))) =
1265 N_Full_Type_Declaration
1268 Type_Def
: constant Node_Id
:=
1270 (Original_Node
(Parent
(T_Typ
)));
1272 if Nkind
(Type_Def
) = N_Derived_Type_Definition
1273 and then Is_Entity_Name
(Subtype_Indication
(Type_Def
))
1274 and then Entity
(Subtype_Indication
(Type_Def
)) = S_Typ
1282 DconT
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
1284 while Present
(Discr
) loop
1285 ItemS
:= Node
(DconS
);
1286 ItemT
:= Node
(DconT
);
1289 not Is_OK_Static_Expression
(ItemS
)
1291 not Is_OK_Static_Expression
(ItemT
);
1293 if Expr_Value
(ItemS
) /= Expr_Value
(ItemT
) then
1294 if Do_Access
then -- needs run-time check.
1297 Apply_Compile_Time_Constraint_Error
1298 (N
, "incorrect value for discriminant&?",
1299 CE_Discriminant_Check_Failed
, Ent
=> Discr
);
1306 Next_Discriminant
(Discr
);
1315 -- Here we need a discriminant check. First build the expression
1316 -- for the comparisons of the discriminants:
1318 -- (n.disc1 /= typ.disc1) or else
1319 -- (n.disc2 /= typ.disc2) or else
1321 -- (n.discn /= typ.discn)
1323 Cond
:= Build_Discriminant_Checks
(N
, T_Typ
);
1325 -- If Lhs is set and is a parameter, then the condition is
1326 -- guarded by: lhs'constrained and then (condition built above)
1328 if Present
(Param_Entity
(Lhs
)) then
1332 Make_Attribute_Reference
(Loc
,
1333 Prefix
=> New_Occurrence_Of
(Param_Entity
(Lhs
), Loc
),
1334 Attribute_Name
=> Name_Constrained
),
1335 Right_Opnd
=> Cond
);
1339 Cond
:= Guard_Access
(Cond
, Loc
, N
);
1343 Make_Raise_Constraint_Error
(Loc
,
1345 Reason
=> CE_Discriminant_Check_Failed
));
1346 end Apply_Discriminant_Check
;
1348 ------------------------
1349 -- Apply_Divide_Check --
1350 ------------------------
1352 procedure Apply_Divide_Check
(N
: Node_Id
) is
1353 Loc
: constant Source_Ptr
:= Sloc
(N
);
1354 Typ
: constant Entity_Id
:= Etype
(N
);
1355 Left
: constant Node_Id
:= Left_Opnd
(N
);
1356 Right
: constant Node_Id
:= Right_Opnd
(N
);
1368 and not Backend_Divide_Checks_On_Target
1370 Determine_Range
(Right
, ROK
, Rlo
, Rhi
);
1372 -- See if division by zero possible, and if so generate test. This
1373 -- part of the test is not controlled by the -gnato switch.
1375 if Do_Division_Check
(N
) then
1376 if (not ROK
) or else (Rlo
<= 0 and then 0 <= Rhi
) then
1378 Make_Raise_Constraint_Error
(Loc
,
1381 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(Right
),
1382 Right_Opnd
=> Make_Integer_Literal
(Loc
, 0)),
1383 Reason
=> CE_Divide_By_Zero
));
1387 -- Test for extremely annoying case of xxx'First divided by -1
1389 if Do_Overflow_Check
(N
) then
1391 if Nkind
(N
) = N_Op_Divide
1392 and then Is_Signed_Integer_Type
(Typ
)
1394 Determine_Range
(Left
, LOK
, Llo
, Lhi
);
1395 LLB
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
1397 if ((not ROK
) or else (Rlo
<= (-1) and then (-1) <= Rhi
))
1399 ((not LOK
) or else (Llo
= LLB
))
1402 Make_Raise_Constraint_Error
(Loc
,
1408 Duplicate_Subexpr_Move_Checks
(Left
),
1409 Right_Opnd
=> Make_Integer_Literal
(Loc
, LLB
)),
1413 Duplicate_Subexpr
(Right
),
1415 Make_Integer_Literal
(Loc
, -1))),
1416 Reason
=> CE_Overflow_Check_Failed
));
1421 end Apply_Divide_Check
;
1423 ----------------------------------
1424 -- Apply_Float_Conversion_Check --
1425 ----------------------------------
1427 -- Let F and I be the source and target types of the conversion.
1428 -- The Ada standard specifies that a floating-point value X is rounded
1429 -- to the nearest integer, with halfway cases being rounded away from
1430 -- zero. The rounded value of X is checked against I'Range.
1432 -- The catch in the above paragraph is that there is no good way
1433 -- to know whether the round-to-integer operation resulted in
1434 -- overflow. A remedy is to perform a range check in the floating-point
1435 -- domain instead, however:
1436 -- (1) The bounds may not be known at compile time
1437 -- (2) The check must take into account possible rounding.
1438 -- (3) The range of type I may not be exactly representable in F.
1439 -- (4) The end-points I'First - 0.5 and I'Last + 0.5 may or may
1440 -- not be in range, depending on the sign of I'First and I'Last.
1441 -- (5) X may be a NaN, which will fail any comparison
1443 -- The following steps take care of these issues converting X:
1444 -- (1) If either I'First or I'Last is not known at compile time, use
1445 -- I'Base instead of I in the next three steps and perform a
1446 -- regular range check against I'Range after conversion.
1447 -- (2) If I'First - 0.5 is representable in F then let Lo be that
1448 -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be
1449 -- F'Machine (T) and let Lo_OK be (Lo >= I'First). In other words,
1450 -- take one of the closest floating-point numbers to T, and see if
1451 -- it is in range or not.
1452 -- (3) If I'Last + 0.5 is representable in F then let Hi be that value
1453 -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be
1454 -- F'Rounding (T) and let Hi_OK be (Hi <= I'Last).
1455 -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo)
1456 -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi)
1458 procedure Apply_Float_Conversion_Check
1460 Target_Typ
: Entity_Id
)
1462 LB
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1463 HB
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1464 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1465 Expr_Type
: constant Entity_Id
:= Base_Type
(Etype
(Ck_Node
));
1466 Target_Base
: constant Entity_Id
:= Implementation_Base_Type
1468 Max_Bound
: constant Uint
:= UI_Expon
1469 (Machine_Radix
(Expr_Type
),
1470 Machine_Mantissa
(Expr_Type
) - 1) - 1;
1471 -- Largest bound, so bound plus or minus half is a machine number of F
1474 Ilast
: Uint
; -- Bounds of integer type
1475 Lo
, Hi
: Ureal
; -- Bounds to check in floating-point domain
1477 Hi_OK
: Boolean; -- True iff Lo resp. Hi belongs to I'Range
1480 Hi_Chk
: Node_Id
; -- Expressions that are False iff check fails
1482 Reason
: RT_Exception_Code
;
1485 if not Compile_Time_Known_Value
(LB
)
1486 or not Compile_Time_Known_Value
(HB
)
1489 -- First check that the value falls in the range of the base
1490 -- type, to prevent overflow during conversion and then
1491 -- perform a regular range check against the (dynamic) bounds.
1493 Par
: constant Node_Id
:= Parent
(Ck_Node
);
1495 pragma Assert
(Target_Base
/= Target_Typ
);
1496 pragma Assert
(Nkind
(Par
) = N_Type_Conversion
);
1498 Temp
: constant Entity_Id
:=
1499 Make_Defining_Identifier
(Loc
,
1500 Chars
=> New_Internal_Name
('T'));
1503 Apply_Float_Conversion_Check
(Ck_Node
, Target_Base
);
1504 Set_Etype
(Temp
, Target_Base
);
1506 Insert_Action
(Parent
(Par
),
1507 Make_Object_Declaration
(Loc
,
1508 Defining_Identifier
=> Temp
,
1509 Object_Definition
=> New_Occurrence_Of
(Target_Typ
, Loc
),
1510 Expression
=> New_Copy_Tree
(Par
)),
1511 Suppress
=> All_Checks
);
1514 Make_Raise_Constraint_Error
(Loc
,
1517 Left_Opnd
=> New_Occurrence_Of
(Temp
, Loc
),
1518 Right_Opnd
=> New_Occurrence_Of
(Target_Typ
, Loc
)),
1519 Reason
=> CE_Range_Check_Failed
));
1520 Rewrite
(Par
, New_Occurrence_Of
(Temp
, Loc
));
1526 -- Get the bounds of the target type
1528 Ifirst
:= Expr_Value
(LB
);
1529 Ilast
:= Expr_Value
(HB
);
1531 -- Check against lower bound
1533 if abs (Ifirst
) < Max_Bound
then
1534 Lo
:= UR_From_Uint
(Ifirst
) - Ureal_Half
;
1535 Lo_OK
:= (Ifirst
> 0);
1537 Lo
:= Machine
(Expr_Type
, UR_From_Uint
(Ifirst
), Round_Even
, Ck_Node
);
1538 Lo_OK
:= (Lo
>= UR_From_Uint
(Ifirst
));
1543 -- Lo_Chk := (X >= Lo)
1545 Lo_Chk
:= Make_Op_Ge
(Loc
,
1546 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1547 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
1550 -- Lo_Chk := (X > Lo)
1552 Lo_Chk
:= Make_Op_Gt
(Loc
,
1553 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1554 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
1557 -- Check against higher bound
1559 if abs (Ilast
) < Max_Bound
then
1560 Hi
:= UR_From_Uint
(Ilast
) + Ureal_Half
;
1561 Hi_OK
:= (Ilast
< 0);
1563 Hi
:= Machine
(Expr_Type
, UR_From_Uint
(Ilast
), Round_Even
, Ck_Node
);
1564 Hi_OK
:= (Hi
<= UR_From_Uint
(Ilast
));
1569 -- Hi_Chk := (X <= Hi)
1571 Hi_Chk
:= Make_Op_Le
(Loc
,
1572 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1573 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
1576 -- Hi_Chk := (X < Hi)
1578 Hi_Chk
:= Make_Op_Lt
(Loc
,
1579 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1580 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
1583 -- If the bounds of the target type are the same as those of the
1584 -- base type, the check is an overflow check as a range check is
1585 -- not performed in these cases.
1587 if Expr_Value
(Type_Low_Bound
(Target_Base
)) = Ifirst
1588 and then Expr_Value
(Type_High_Bound
(Target_Base
)) = Ilast
1590 Reason
:= CE_Overflow_Check_Failed
;
1592 Reason
:= CE_Range_Check_Failed
;
1595 -- Raise CE if either conditions does not hold
1597 Insert_Action
(Ck_Node
,
1598 Make_Raise_Constraint_Error
(Loc
,
1599 Condition
=> Make_Op_Not
(Loc
, Make_Op_And
(Loc
, Lo_Chk
, Hi_Chk
)),
1601 end Apply_Float_Conversion_Check
;
1603 ------------------------
1604 -- Apply_Length_Check --
1605 ------------------------
1607 procedure Apply_Length_Check
1609 Target_Typ
: Entity_Id
;
1610 Source_Typ
: Entity_Id
:= Empty
)
1613 Apply_Selected_Length_Checks
1614 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
1615 end Apply_Length_Check
;
1617 -----------------------
1618 -- Apply_Range_Check --
1619 -----------------------
1621 procedure Apply_Range_Check
1623 Target_Typ
: Entity_Id
;
1624 Source_Typ
: Entity_Id
:= Empty
)
1627 Apply_Selected_Range_Checks
1628 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
1629 end Apply_Range_Check
;
1631 ------------------------------
1632 -- Apply_Scalar_Range_Check --
1633 ------------------------------
1635 -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check
1636 -- flag off if it is already set on.
1638 procedure Apply_Scalar_Range_Check
1640 Target_Typ
: Entity_Id
;
1641 Source_Typ
: Entity_Id
:= Empty
;
1642 Fixed_Int
: Boolean := False)
1644 Parnt
: constant Node_Id
:= Parent
(Expr
);
1646 Arr
: Node_Id
:= Empty
; -- initialize to prevent warning
1647 Arr_Typ
: Entity_Id
:= Empty
; -- initialize to prevent warning
1650 Is_Subscr_Ref
: Boolean;
1651 -- Set true if Expr is a subscript
1653 Is_Unconstrained_Subscr_Ref
: Boolean;
1654 -- Set true if Expr is a subscript of an unconstrained array. In this
1655 -- case we do not attempt to do an analysis of the value against the
1656 -- range of the subscript, since we don't know the actual subtype.
1659 -- Set to True if Expr should be regarded as a real value
1660 -- even though the type of Expr might be discrete.
1662 procedure Bad_Value
;
1663 -- Procedure called if value is determined to be out of range
1669 procedure Bad_Value
is
1671 Apply_Compile_Time_Constraint_Error
1672 (Expr
, "value not in range of}?", CE_Range_Check_Failed
,
1677 -- Start of processing for Apply_Scalar_Range_Check
1680 if Inside_A_Generic
then
1683 -- Return if check obviously not needed. Note that we do not check
1684 -- for the expander being inactive, since this routine does not
1685 -- insert any code, but it does generate useful warnings sometimes,
1686 -- which we would like even if we are in semantics only mode.
1688 elsif Target_Typ
= Any_Type
1689 or else not Is_Scalar_Type
(Target_Typ
)
1690 or else Raises_Constraint_Error
(Expr
)
1695 -- Now, see if checks are suppressed
1698 Is_List_Member
(Expr
) and then Nkind
(Parnt
) = N_Indexed_Component
;
1700 if Is_Subscr_Ref
then
1701 Arr
:= Prefix
(Parnt
);
1702 Arr_Typ
:= Get_Actual_Subtype_If_Available
(Arr
);
1705 if not Do_Range_Check
(Expr
) then
1707 -- Subscript reference. Check for Index_Checks suppressed
1709 if Is_Subscr_Ref
then
1711 -- Check array type and its base type
1713 if Index_Checks_Suppressed
(Arr_Typ
)
1714 or else Index_Checks_Suppressed
(Base_Type
(Arr_Typ
))
1718 -- Check array itself if it is an entity name
1720 elsif Is_Entity_Name
(Arr
)
1721 and then Index_Checks_Suppressed
(Entity
(Arr
))
1725 -- Check expression itself if it is an entity name
1727 elsif Is_Entity_Name
(Expr
)
1728 and then Index_Checks_Suppressed
(Entity
(Expr
))
1733 -- All other cases, check for Range_Checks suppressed
1736 -- Check target type and its base type
1738 if Range_Checks_Suppressed
(Target_Typ
)
1739 or else Range_Checks_Suppressed
(Base_Type
(Target_Typ
))
1743 -- Check expression itself if it is an entity name
1745 elsif Is_Entity_Name
(Expr
)
1746 and then Range_Checks_Suppressed
(Entity
(Expr
))
1750 -- If Expr is part of an assignment statement, then check
1751 -- left side of assignment if it is an entity name.
1753 elsif Nkind
(Parnt
) = N_Assignment_Statement
1754 and then Is_Entity_Name
(Name
(Parnt
))
1755 and then Range_Checks_Suppressed
(Entity
(Name
(Parnt
)))
1762 -- Do not set range checks if they are killed
1764 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
1765 and then Kill_Range_Check
(Expr
)
1770 -- Do not set range checks for any values from System.Scalar_Values
1771 -- since the whole idea of such values is to avoid checking them!
1773 if Is_Entity_Name
(Expr
)
1774 and then Is_RTU
(Scope
(Entity
(Expr
)), System_Scalar_Values
)
1779 -- Now see if we need a check
1781 if No
(Source_Typ
) then
1782 S_Typ
:= Etype
(Expr
);
1784 S_Typ
:= Source_Typ
;
1787 if not Is_Scalar_Type
(S_Typ
) or else S_Typ
= Any_Type
then
1791 Is_Unconstrained_Subscr_Ref
:=
1792 Is_Subscr_Ref
and then not Is_Constrained
(Arr_Typ
);
1794 -- Always do a range check if the source type includes infinities
1795 -- and the target type does not include infinities. We do not do
1796 -- this if range checks are killed.
1798 if Is_Floating_Point_Type
(S_Typ
)
1799 and then Has_Infinities
(S_Typ
)
1800 and then not Has_Infinities
(Target_Typ
)
1802 Enable_Range_Check
(Expr
);
1805 -- Return if we know expression is definitely in the range of
1806 -- the target type as determined by Determine_Range. Right now
1807 -- we only do this for discrete types, and not fixed-point or
1808 -- floating-point types.
1810 -- The additional less-precise tests below catch these cases.
1812 -- Note: skip this if we are given a source_typ, since the point
1813 -- of supplying a Source_Typ is to stop us looking at the expression.
1814 -- could sharpen this test to be out parameters only ???
1816 if Is_Discrete_Type
(Target_Typ
)
1817 and then Is_Discrete_Type
(Etype
(Expr
))
1818 and then not Is_Unconstrained_Subscr_Ref
1819 and then No
(Source_Typ
)
1822 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1823 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1828 if Compile_Time_Known_Value
(Tlo
)
1829 and then Compile_Time_Known_Value
(Thi
)
1832 Lov
: constant Uint
:= Expr_Value
(Tlo
);
1833 Hiv
: constant Uint
:= Expr_Value
(Thi
);
1836 -- If range is null, we for sure have a constraint error
1837 -- (we don't even need to look at the value involved,
1838 -- since all possible values will raise CE).
1845 -- Otherwise determine range of value
1847 Determine_Range
(Expr
, OK
, Lo
, Hi
);
1851 -- If definitely in range, all OK
1853 if Lo
>= Lov
and then Hi
<= Hiv
then
1856 -- If definitely not in range, warn
1858 elsif Lov
> Hi
or else Hiv
< Lo
then
1862 -- Otherwise we don't know
1874 Is_Floating_Point_Type
(S_Typ
)
1875 or else (Is_Fixed_Point_Type
(S_Typ
) and then not Fixed_Int
);
1877 -- Check if we can determine at compile time whether Expr is in the
1878 -- range of the target type. Note that if S_Typ is within the bounds
1879 -- of Target_Typ then this must be the case. This check is meaningful
1880 -- only if this is not a conversion between integer and real types.
1882 if not Is_Unconstrained_Subscr_Ref
1884 Is_Discrete_Type
(S_Typ
) = Is_Discrete_Type
(Target_Typ
)
1886 (In_Subrange_Of
(S_Typ
, Target_Typ
, Fixed_Int
)
1888 Is_In_Range
(Expr
, Target_Typ
, Fixed_Int
, Int_Real
))
1892 elsif Is_Out_Of_Range
(Expr
, Target_Typ
, Fixed_Int
, Int_Real
) then
1896 -- In the floating-point case, we only do range checks if the
1897 -- type is constrained. We definitely do NOT want range checks
1898 -- for unconstrained types, since we want to have infinities
1900 elsif Is_Floating_Point_Type
(S_Typ
) then
1901 if Is_Constrained
(S_Typ
) then
1902 Enable_Range_Check
(Expr
);
1905 -- For all other cases we enable a range check unconditionally
1908 Enable_Range_Check
(Expr
);
1911 end Apply_Scalar_Range_Check
;
1913 ----------------------------------
1914 -- Apply_Selected_Length_Checks --
1915 ----------------------------------
1917 procedure Apply_Selected_Length_Checks
1919 Target_Typ
: Entity_Id
;
1920 Source_Typ
: Entity_Id
;
1921 Do_Static
: Boolean)
1924 R_Result
: Check_Result
;
1927 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1928 Checks_On
: constant Boolean :=
1929 (not Index_Checks_Suppressed
(Target_Typ
))
1931 (not Length_Checks_Suppressed
(Target_Typ
));
1934 if not Expander_Active
then
1939 Selected_Length_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
1941 for J
in 1 .. 2 loop
1942 R_Cno
:= R_Result
(J
);
1943 exit when No
(R_Cno
);
1945 -- A length check may mention an Itype which is attached to a
1946 -- subsequent node. At the top level in a package this can cause
1947 -- an order-of-elaboration problem, so we make sure that the itype
1948 -- is referenced now.
1950 if Ekind
(Current_Scope
) = E_Package
1951 and then Is_Compilation_Unit
(Current_Scope
)
1953 Ensure_Defined
(Target_Typ
, Ck_Node
);
1955 if Present
(Source_Typ
) then
1956 Ensure_Defined
(Source_Typ
, Ck_Node
);
1958 elsif Is_Itype
(Etype
(Ck_Node
)) then
1959 Ensure_Defined
(Etype
(Ck_Node
), Ck_Node
);
1963 -- If the item is a conditional raise of constraint error,
1964 -- then have a look at what check is being performed and
1967 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
1968 and then Present
(Condition
(R_Cno
))
1970 Cond
:= Condition
(R_Cno
);
1972 if not Has_Dynamic_Length_Check
(Ck_Node
)
1975 Insert_Action
(Ck_Node
, R_Cno
);
1977 if not Do_Static
then
1978 Set_Has_Dynamic_Length_Check
(Ck_Node
);
1982 -- Output a warning if the condition is known to be True
1984 if Is_Entity_Name
(Cond
)
1985 and then Entity
(Cond
) = Standard_True
1987 Apply_Compile_Time_Constraint_Error
1988 (Ck_Node
, "wrong length for array of}?",
1989 CE_Length_Check_Failed
,
1993 -- If we were only doing a static check, or if checks are not
1994 -- on, then we want to delete the check, since it is not needed.
1995 -- We do this by replacing the if statement by a null statement
1997 elsif Do_Static
or else not Checks_On
then
1998 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
2002 Install_Static_Check
(R_Cno
, Loc
);
2007 end Apply_Selected_Length_Checks
;
2009 ---------------------------------
2010 -- Apply_Selected_Range_Checks --
2011 ---------------------------------
2013 procedure Apply_Selected_Range_Checks
2015 Target_Typ
: Entity_Id
;
2016 Source_Typ
: Entity_Id
;
2017 Do_Static
: Boolean)
2020 R_Result
: Check_Result
;
2023 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
2024 Checks_On
: constant Boolean :=
2025 (not Index_Checks_Suppressed
(Target_Typ
))
2027 (not Range_Checks_Suppressed
(Target_Typ
));
2030 if not Expander_Active
or else not Checks_On
then
2035 Selected_Range_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
2037 for J
in 1 .. 2 loop
2039 R_Cno
:= R_Result
(J
);
2040 exit when No
(R_Cno
);
2042 -- If the item is a conditional raise of constraint error,
2043 -- then have a look at what check is being performed and
2046 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
2047 and then Present
(Condition
(R_Cno
))
2049 Cond
:= Condition
(R_Cno
);
2051 if not Has_Dynamic_Range_Check
(Ck_Node
) then
2052 Insert_Action
(Ck_Node
, R_Cno
);
2054 if not Do_Static
then
2055 Set_Has_Dynamic_Range_Check
(Ck_Node
);
2059 -- Output a warning if the condition is known to be True
2061 if Is_Entity_Name
(Cond
)
2062 and then Entity
(Cond
) = Standard_True
2064 -- Since an N_Range is technically not an expression, we
2065 -- have to set one of the bounds to C_E and then just flag
2066 -- the N_Range. The warning message will point to the
2067 -- lower bound and complain about a range, which seems OK.
2069 if Nkind
(Ck_Node
) = N_Range
then
2070 Apply_Compile_Time_Constraint_Error
2071 (Low_Bound
(Ck_Node
), "static range out of bounds of}?",
2072 CE_Range_Check_Failed
,
2076 Set_Raises_Constraint_Error
(Ck_Node
);
2079 Apply_Compile_Time_Constraint_Error
2080 (Ck_Node
, "static value out of range of}?",
2081 CE_Range_Check_Failed
,
2086 -- If we were only doing a static check, or if checks are not
2087 -- on, then we want to delete the check, since it is not needed.
2088 -- We do this by replacing the if statement by a null statement
2090 elsif Do_Static
or else not Checks_On
then
2091 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
2095 Install_Static_Check
(R_Cno
, Loc
);
2098 end Apply_Selected_Range_Checks
;
2100 -------------------------------
2101 -- Apply_Static_Length_Check --
2102 -------------------------------
2104 procedure Apply_Static_Length_Check
2106 Target_Typ
: Entity_Id
;
2107 Source_Typ
: Entity_Id
:= Empty
)
2110 Apply_Selected_Length_Checks
2111 (Expr
, Target_Typ
, Source_Typ
, Do_Static
=> True);
2112 end Apply_Static_Length_Check
;
2114 -------------------------------------
2115 -- Apply_Subscript_Validity_Checks --
2116 -------------------------------------
2118 procedure Apply_Subscript_Validity_Checks
(Expr
: Node_Id
) is
2122 pragma Assert
(Nkind
(Expr
) = N_Indexed_Component
);
2124 -- Loop through subscripts
2126 Sub
:= First
(Expressions
(Expr
));
2127 while Present
(Sub
) loop
2129 -- Check one subscript. Note that we do not worry about
2130 -- enumeration type with holes, since we will convert the
2131 -- value to a Pos value for the subscript, and that convert
2132 -- will do the necessary validity check.
2134 Ensure_Valid
(Sub
, Holes_OK
=> True);
2136 -- Move to next subscript
2140 end Apply_Subscript_Validity_Checks
;
2142 ----------------------------------
2143 -- Apply_Type_Conversion_Checks --
2144 ----------------------------------
2146 procedure Apply_Type_Conversion_Checks
(N
: Node_Id
) is
2147 Target_Type
: constant Entity_Id
:= Etype
(N
);
2148 Target_Base
: constant Entity_Id
:= Base_Type
(Target_Type
);
2149 Expr
: constant Node_Id
:= Expression
(N
);
2150 Expr_Type
: constant Entity_Id
:= Etype
(Expr
);
2153 if Inside_A_Generic
then
2156 -- Skip these checks if serious errors detected, there are some nasty
2157 -- situations of incomplete trees that blow things up.
2159 elsif Serious_Errors_Detected
> 0 then
2162 -- Scalar type conversions of the form Target_Type (Expr) require
2163 -- a range check if we cannot be sure that Expr is in the base type
2164 -- of Target_Typ and also that Expr is in the range of Target_Typ.
2165 -- These are not quite the same condition from an implementation
2166 -- point of view, but clearly the second includes the first.
2168 elsif Is_Scalar_Type
(Target_Type
) then
2170 Conv_OK
: constant Boolean := Conversion_OK
(N
);
2171 -- If the Conversion_OK flag on the type conversion is set
2172 -- and no floating point type is involved in the type conversion
2173 -- then fixed point values must be read as integral values.
2175 Float_To_Int
: constant Boolean :=
2176 Is_Floating_Point_Type
(Expr_Type
)
2177 and then Is_Integer_Type
(Target_Type
);
2180 if not Overflow_Checks_Suppressed
(Target_Base
)
2181 and then not In_Subrange_Of
(Expr_Type
, Target_Base
, Conv_OK
)
2182 and then not Float_To_Int
2184 Set_Do_Overflow_Check
(N
);
2187 if not Range_Checks_Suppressed
(Target_Type
)
2188 and then not Range_Checks_Suppressed
(Expr_Type
)
2190 if Float_To_Int
then
2191 Apply_Float_Conversion_Check
(Expr
, Target_Type
);
2193 Apply_Scalar_Range_Check
2194 (Expr
, Target_Type
, Fixed_Int
=> Conv_OK
);
2199 elsif Comes_From_Source
(N
)
2200 and then Is_Record_Type
(Target_Type
)
2201 and then Is_Derived_Type
(Target_Type
)
2202 and then not Is_Tagged_Type
(Target_Type
)
2203 and then not Is_Constrained
(Target_Type
)
2204 and then Present
(Stored_Constraint
(Target_Type
))
2206 -- An unconstrained derived type may have inherited discriminant
2207 -- Build an actual discriminant constraint list using the stored
2208 -- constraint, to verify that the expression of the parent type
2209 -- satisfies the constraints imposed by the (unconstrained!)
2210 -- derived type. This applies to value conversions, not to view
2211 -- conversions of tagged types.
2214 Loc
: constant Source_Ptr
:= Sloc
(N
);
2216 Constraint
: Elmt_Id
;
2217 Discr_Value
: Node_Id
;
2220 New_Constraints
: constant Elist_Id
:= New_Elmt_List
;
2221 Old_Constraints
: constant Elist_Id
:=
2222 Discriminant_Constraint
(Expr_Type
);
2225 Constraint
:= First_Elmt
(Stored_Constraint
(Target_Type
));
2227 while Present
(Constraint
) loop
2228 Discr_Value
:= Node
(Constraint
);
2230 if Is_Entity_Name
(Discr_Value
)
2231 and then Ekind
(Entity
(Discr_Value
)) = E_Discriminant
2233 Discr
:= Corresponding_Discriminant
(Entity
(Discr_Value
));
2236 and then Scope
(Discr
) = Base_Type
(Expr_Type
)
2238 -- Parent is constrained by new discriminant. Obtain
2239 -- Value of original discriminant in expression. If
2240 -- the new discriminant has been used to constrain more
2241 -- than one of the stored discriminants, this will
2242 -- provide the required consistency check.
2245 Make_Selected_Component
(Loc
,
2247 Duplicate_Subexpr_No_Checks
2248 (Expr
, Name_Req
=> True),
2250 Make_Identifier
(Loc
, Chars
(Discr
))),
2254 -- Discriminant of more remote ancestor ???
2259 -- Derived type definition has an explicit value for
2260 -- this stored discriminant.
2264 (Duplicate_Subexpr_No_Checks
(Discr_Value
),
2268 Next_Elmt
(Constraint
);
2271 -- Use the unconstrained expression type to retrieve the
2272 -- discriminants of the parent, and apply momentarily the
2273 -- discriminant constraint synthesized above.
2275 Set_Discriminant_Constraint
(Expr_Type
, New_Constraints
);
2276 Cond
:= Build_Discriminant_Checks
(Expr
, Expr_Type
);
2277 Set_Discriminant_Constraint
(Expr_Type
, Old_Constraints
);
2280 Make_Raise_Constraint_Error
(Loc
,
2282 Reason
=> CE_Discriminant_Check_Failed
));
2285 -- For arrays, conversions are applied during expansion, to take
2286 -- into accounts changes of representation. The checks become range
2287 -- checks on the base type or length checks on the subtype, depending
2288 -- on whether the target type is unconstrained or constrained.
2293 end Apply_Type_Conversion_Checks
;
2295 ----------------------------------------------
2296 -- Apply_Universal_Integer_Attribute_Checks --
2297 ----------------------------------------------
2299 procedure Apply_Universal_Integer_Attribute_Checks
(N
: Node_Id
) is
2300 Loc
: constant Source_Ptr
:= Sloc
(N
);
2301 Typ
: constant Entity_Id
:= Etype
(N
);
2304 if Inside_A_Generic
then
2307 -- Nothing to do if checks are suppressed
2309 elsif Range_Checks_Suppressed
(Typ
)
2310 and then Overflow_Checks_Suppressed
(Typ
)
2314 -- Nothing to do if the attribute does not come from source. The
2315 -- internal attributes we generate of this type do not need checks,
2316 -- and furthermore the attempt to check them causes some circular
2317 -- elaboration orders when dealing with packed types.
2319 elsif not Comes_From_Source
(N
) then
2322 -- If the prefix is a selected component that depends on a discriminant
2323 -- the check may improperly expose a discriminant instead of using
2324 -- the bounds of the object itself. Set the type of the attribute to
2325 -- the base type of the context, so that a check will be imposed when
2326 -- needed (e.g. if the node appears as an index).
2328 elsif Nkind
(Prefix
(N
)) = N_Selected_Component
2329 and then Ekind
(Typ
) = E_Signed_Integer_Subtype
2330 and then Depends_On_Discriminant
(Scalar_Range
(Typ
))
2332 Set_Etype
(N
, Base_Type
(Typ
));
2334 -- Otherwise, replace the attribute node with a type conversion
2335 -- node whose expression is the attribute, retyped to universal
2336 -- integer, and whose subtype mark is the target type. The call
2337 -- to analyze this conversion will set range and overflow checks
2338 -- as required for proper detection of an out of range value.
2341 Set_Etype
(N
, Universal_Integer
);
2342 Set_Analyzed
(N
, True);
2345 Make_Type_Conversion
(Loc
,
2346 Subtype_Mark
=> New_Occurrence_Of
(Typ
, Loc
),
2347 Expression
=> Relocate_Node
(N
)));
2349 Analyze_And_Resolve
(N
, Typ
);
2353 end Apply_Universal_Integer_Attribute_Checks
;
2355 -------------------------------
2356 -- Build_Discriminant_Checks --
2357 -------------------------------
2359 function Build_Discriminant_Checks
2361 T_Typ
: Entity_Id
) return Node_Id
2363 Loc
: constant Source_Ptr
:= Sloc
(N
);
2366 Disc_Ent
: Entity_Id
;
2372 Disc
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
2374 -- For a fully private type, use the discriminants of the parent type
2376 if Is_Private_Type
(T_Typ
)
2377 and then No
(Full_View
(T_Typ
))
2379 Disc_Ent
:= First_Discriminant
(Etype
(Base_Type
(T_Typ
)));
2381 Disc_Ent
:= First_Discriminant
(T_Typ
);
2384 while Present
(Disc
) loop
2385 Dval
:= Node
(Disc
);
2387 if Nkind
(Dval
) = N_Identifier
2388 and then Ekind
(Entity
(Dval
)) = E_Discriminant
2390 Dval
:= New_Occurrence_Of
(Discriminal
(Entity
(Dval
)), Loc
);
2392 Dval
:= Duplicate_Subexpr_No_Checks
(Dval
);
2395 -- If we have an Unchecked_Union node, we can infer the discriminants
2398 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
2400 Get_Discriminant_Value
(
2401 First_Discriminant
(T_Typ
),
2403 Stored_Constraint
(T_Typ
)));
2407 Make_Selected_Component
(Loc
,
2409 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
2411 Make_Identifier
(Loc
, Chars
(Disc_Ent
)));
2413 Set_Is_In_Discriminant_Check
(Dref
);
2416 Evolve_Or_Else
(Cond
,
2419 Right_Opnd
=> Dval
));
2422 Next_Discriminant
(Disc_Ent
);
2426 end Build_Discriminant_Checks
;
2428 -----------------------------------
2429 -- Check_Valid_Lvalue_Subscripts --
2430 -----------------------------------
2432 procedure Check_Valid_Lvalue_Subscripts
(Expr
: Node_Id
) is
2434 -- Skip this if range checks are suppressed
2436 if Range_Checks_Suppressed
(Etype
(Expr
)) then
2439 -- Only do this check for expressions that come from source. We
2440 -- assume that expander generated assignments explicitly include
2441 -- any necessary checks. Note that this is not just an optimization,
2442 -- it avoids infinite recursions!
2444 elsif not Comes_From_Source
(Expr
) then
2447 -- For a selected component, check the prefix
2449 elsif Nkind
(Expr
) = N_Selected_Component
then
2450 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
2453 -- Case of indexed component
2455 elsif Nkind
(Expr
) = N_Indexed_Component
then
2456 Apply_Subscript_Validity_Checks
(Expr
);
2458 -- Prefix may itself be or contain an indexed component, and
2459 -- these subscripts need checking as well
2461 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
2463 end Check_Valid_Lvalue_Subscripts
;
2465 ----------------------------------
2466 -- Null_Exclusion_Static_Checks --
2467 ----------------------------------
2469 procedure Null_Exclusion_Static_Checks
(N
: Node_Id
) is
2470 K
: constant Node_Kind
:= Nkind
(N
);
2472 Related_Nod
: Node_Id
;
2473 Has_Null_Exclusion
: Boolean := False;
2475 type Msg_Kind
is (Components
, Formals
, Objects
);
2476 Msg_K
: Msg_Kind
:= Objects
;
2477 -- Used by local subprograms to generate precise error messages
2479 procedure Check_Must_Be_Access
2481 Has_Null_Exclusion
: Boolean);
2482 -- ??? local subprograms must have comment on spec
2484 procedure Check_Already_Null_Excluding_Type
2486 Has_Null_Exclusion
: Boolean;
2487 Related_Nod
: Node_Id
);
2488 -- ??? local subprograms must have comment on spec
2490 procedure Check_Must_Be_Initialized
2492 Related_Nod
: Node_Id
);
2493 -- ??? local subprograms must have comment on spec
2495 procedure Check_Null_Not_Allowed
(N
: Node_Id
);
2496 -- ??? local subprograms must have comment on spec
2498 -- ??? following bodies lack comments
2500 --------------------------
2501 -- Check_Must_Be_Access --
2502 --------------------------
2504 procedure Check_Must_Be_Access
2506 Has_Null_Exclusion
: Boolean)
2509 if Has_Null_Exclusion
2510 and then not Is_Access_Type
(Typ
)
2512 Error_Msg_N
("(Ada 2005) must be an access type", Related_Nod
);
2514 end Check_Must_Be_Access
;
2516 ---------------------------------------
2517 -- Check_Already_Null_Excluding_Type --
2518 ---------------------------------------
2520 procedure Check_Already_Null_Excluding_Type
2522 Has_Null_Exclusion
: Boolean;
2523 Related_Nod
: Node_Id
)
2526 if Has_Null_Exclusion
2527 and then Can_Never_Be_Null
(Typ
)
2530 ("(Ada 2005) already a null-excluding type", Related_Nod
);
2532 end Check_Already_Null_Excluding_Type
;
2534 -------------------------------
2535 -- Check_Must_Be_Initialized --
2536 -------------------------------
2538 procedure Check_Must_Be_Initialized
2540 Related_Nod
: Node_Id
)
2542 Expr
: constant Node_Id
:= Expression
(N
);
2545 pragma Assert
(Nkind
(N
) = N_Component_Declaration
2546 or else Nkind
(N
) = N_Object_Declaration
);
2548 if not Present
(Expr
) then
2552 ("(Ada 2005) null-excluding components must be " &
2553 "initialized", Related_Nod
);
2557 ("(Ada 2005) null-excluding formals must be initialized",
2562 ("(Ada 2005) null-excluding objects must be initialized",
2566 end Check_Must_Be_Initialized
;
2568 ----------------------------
2569 -- Check_Null_Not_Allowed --
2570 ----------------------------
2572 procedure Check_Null_Not_Allowed
(N
: Node_Id
) is
2573 Expr
: constant Node_Id
:= Expression
(N
);
2577 and then Nkind
(Expr
) = N_Null
2582 ("(Ada 2005) NULL not allowed in null-excluding " &
2583 "components", Expr
);
2587 ("(Ada 2005) NULL not allowed in null-excluding formals",
2592 ("(Ada 2005) NULL not allowed in null-excluding objects",
2596 end Check_Null_Not_Allowed
;
2598 -- Start of processing for Null_Exclusion_Static_Checks
2601 pragma Assert
(K
= N_Component_Declaration
2602 or else K
= N_Parameter_Specification
2603 or else K
= N_Object_Declaration
2604 or else K
= N_Discriminant_Specification
2605 or else K
= N_Allocator
);
2608 when N_Component_Declaration
=>
2609 Msg_K
:= Components
;
2611 if not Present
(Access_Definition
(Component_Definition
(N
))) then
2612 Has_Null_Exclusion
:= Null_Exclusion_Present
2613 (Component_Definition
(N
));
2614 Typ
:= Etype
(Subtype_Indication
(Component_Definition
(N
)));
2615 Related_Nod
:= Subtype_Indication
(Component_Definition
(N
));
2616 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2617 Check_Already_Null_Excluding_Type
2618 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2619 Check_Must_Be_Initialized
(N
, Related_Nod
);
2622 Check_Null_Not_Allowed
(N
);
2624 when N_Parameter_Specification
=>
2626 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2627 Typ
:= Entity
(Parameter_Type
(N
));
2628 Related_Nod
:= Parameter_Type
(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_Null_Not_Allowed
(N
);
2634 when N_Object_Declaration
=>
2636 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2637 Typ
:= Entity
(Object_Definition
(N
));
2638 Related_Nod
:= Object_Definition
(N
);
2639 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2640 Check_Already_Null_Excluding_Type
2641 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2642 Check_Must_Be_Initialized
(N
, Related_Nod
);
2643 Check_Null_Not_Allowed
(N
);
2645 when N_Discriminant_Specification
=>
2646 Msg_K
:= Components
;
2648 if Nkind
(Discriminant_Type
(N
)) /= N_Access_Definition
then
2649 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2650 Typ
:= Etype
(Defining_Identifier
(N
));
2651 Related_Nod
:= Discriminant_Type
(N
);
2652 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2653 Check_Already_Null_Excluding_Type
2654 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2657 Check_Null_Not_Allowed
(N
);
2661 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2662 Typ
:= Etype
(Expression
(N
));
2664 if Nkind
(Expression
(N
)) = N_Qualified_Expression
then
2665 Related_Nod
:= Subtype_Mark
(Expression
(N
));
2667 Related_Nod
:= Expression
(N
);
2670 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2671 Check_Already_Null_Excluding_Type
2672 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2673 Check_Null_Not_Allowed
(N
);
2676 raise Program_Error
;
2678 end Null_Exclusion_Static_Checks
;
2680 ----------------------------------
2681 -- Conditional_Statements_Begin --
2682 ----------------------------------
2684 procedure Conditional_Statements_Begin
is
2686 Saved_Checks_TOS
:= Saved_Checks_TOS
+ 1;
2688 -- If stack overflows, kill all checks, that way we know to
2689 -- simply reset the number of saved checks to zero on return.
2690 -- This should never occur in practice.
2692 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
2695 -- In the normal case, we just make a new stack entry saving
2696 -- the current number of saved checks for a later restore.
2699 Saved_Checks_Stack
(Saved_Checks_TOS
) := Num_Saved_Checks
;
2701 if Debug_Flag_CC
then
2702 w
("Conditional_Statements_Begin: Num_Saved_Checks = ",
2706 end Conditional_Statements_Begin
;
2708 --------------------------------
2709 -- Conditional_Statements_End --
2710 --------------------------------
2712 procedure Conditional_Statements_End
is
2714 pragma Assert
(Saved_Checks_TOS
> 0);
2716 -- If the saved checks stack overflowed, then we killed all
2717 -- checks, so setting the number of saved checks back to
2718 -- zero is correct. This should never occur in practice.
2720 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
2721 Num_Saved_Checks
:= 0;
2723 -- In the normal case, restore the number of saved checks
2724 -- from the top stack entry.
2727 Num_Saved_Checks
:= Saved_Checks_Stack
(Saved_Checks_TOS
);
2728 if Debug_Flag_CC
then
2729 w
("Conditional_Statements_End: Num_Saved_Checks = ",
2734 Saved_Checks_TOS
:= Saved_Checks_TOS
- 1;
2735 end Conditional_Statements_End
;
2737 ---------------------
2738 -- Determine_Range --
2739 ---------------------
2741 Cache_Size
: constant := 2 ** 10;
2742 type Cache_Index
is range 0 .. Cache_Size
- 1;
2743 -- Determine size of below cache (power of 2 is more efficient!)
2745 Determine_Range_Cache_N
: array (Cache_Index
) of Node_Id
;
2746 Determine_Range_Cache_Lo
: array (Cache_Index
) of Uint
;
2747 Determine_Range_Cache_Hi
: array (Cache_Index
) of Uint
;
2748 -- The above arrays are used to implement a small direct cache
2749 -- for Determine_Range calls. Because of the way Determine_Range
2750 -- recursively traces subexpressions, and because overflow checking
2751 -- calls the routine on the way up the tree, a quadratic behavior
2752 -- can otherwise be encountered in large expressions. The cache
2753 -- entry for node N is stored in the (N mod Cache_Size) entry, and
2754 -- can be validated by checking the actual node value stored there.
2756 procedure Determine_Range
2762 Typ
: constant Entity_Id
:= Etype
(N
);
2766 -- Lo and Hi bounds of left operand
2770 -- Lo and Hi bounds of right (or only) operand
2773 -- Temp variable used to hold a bound node
2776 -- High bound of base type of expression
2780 -- Refined values for low and high bounds, after tightening
2783 -- Used in lower level calls to indicate if call succeeded
2785 Cindex
: Cache_Index
;
2786 -- Used to search cache
2788 function OK_Operands
return Boolean;
2789 -- Used for binary operators. Determines the ranges of the left and
2790 -- right operands, and if they are both OK, returns True, and puts
2791 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left
2797 function OK_Operands
return Boolean is
2799 Determine_Range
(Left_Opnd
(N
), OK1
, Lo_Left
, Hi_Left
);
2805 Determine_Range
(Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
);
2809 -- Start of processing for Determine_Range
2812 -- Prevent junk warnings by initializing range variables
2819 -- If the type is not discrete, or is undefined, then we can't
2820 -- do anything about determining the range.
2822 if No
(Typ
) or else not Is_Discrete_Type
(Typ
)
2823 or else Error_Posted
(N
)
2829 -- For all other cases, we can determine the range
2833 -- If value is compile time known, then the possible range is the
2834 -- one value that we know this expression definitely has!
2836 if Compile_Time_Known_Value
(N
) then
2837 Lo
:= Expr_Value
(N
);
2842 -- Return if already in the cache
2844 Cindex
:= Cache_Index
(N
mod Cache_Size
);
2846 if Determine_Range_Cache_N
(Cindex
) = N
then
2847 Lo
:= Determine_Range_Cache_Lo
(Cindex
);
2848 Hi
:= Determine_Range_Cache_Hi
(Cindex
);
2852 -- Otherwise, start by finding the bounds of the type of the
2853 -- expression, the value cannot be outside this range (if it
2854 -- is, then we have an overflow situation, which is a separate
2855 -- check, we are talking here only about the expression value).
2857 -- We use the actual bound unless it is dynamic, in which case
2858 -- use the corresponding base type bound if possible. If we can't
2859 -- get a bound then we figure we can't determine the range (a
2860 -- peculiar case, that perhaps cannot happen, but there is no
2861 -- point in bombing in this optimization circuit.
2863 -- First the low bound
2865 Bound
:= Type_Low_Bound
(Typ
);
2867 if Compile_Time_Known_Value
(Bound
) then
2868 Lo
:= Expr_Value
(Bound
);
2870 elsif Compile_Time_Known_Value
(Type_Low_Bound
(Base_Type
(Typ
))) then
2871 Lo
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
2878 -- Now the high bound
2880 Bound
:= Type_High_Bound
(Typ
);
2882 -- We need the high bound of the base type later on, and this should
2883 -- always be compile time known. Again, it is not clear that this
2884 -- can ever be false, but no point in bombing.
2886 if Compile_Time_Known_Value
(Type_High_Bound
(Base_Type
(Typ
))) then
2887 Hbound
:= Expr_Value
(Type_High_Bound
(Base_Type
(Typ
)));
2895 -- If we have a static subtype, then that may have a tighter bound
2896 -- so use the upper bound of the subtype instead in this case.
2898 if Compile_Time_Known_Value
(Bound
) then
2899 Hi
:= Expr_Value
(Bound
);
2902 -- We may be able to refine this value in certain situations. If
2903 -- refinement is possible, then Lor and Hir are set to possibly
2904 -- tighter bounds, and OK1 is set to True.
2908 -- For unary plus, result is limited by range of operand
2911 Determine_Range
(Right_Opnd
(N
), OK1
, Lor
, Hir
);
2913 -- For unary minus, determine range of operand, and negate it
2916 Determine_Range
(Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
);
2923 -- For binary addition, get range of each operand and do the
2924 -- addition to get the result range.
2928 Lor
:= Lo_Left
+ Lo_Right
;
2929 Hir
:= Hi_Left
+ Hi_Right
;
2932 -- Division is tricky. The only case we consider is where the
2933 -- right operand is a positive constant, and in this case we
2934 -- simply divide the bounds of the left operand
2938 if Lo_Right
= Hi_Right
2939 and then Lo_Right
> 0
2941 Lor
:= Lo_Left
/ Lo_Right
;
2942 Hir
:= Hi_Left
/ Lo_Right
;
2949 -- For binary subtraction, get range of each operand and do
2950 -- the worst case subtraction to get the result range.
2952 when N_Op_Subtract
=>
2954 Lor
:= Lo_Left
- Hi_Right
;
2955 Hir
:= Hi_Left
- Lo_Right
;
2958 -- For MOD, if right operand is a positive constant, then
2959 -- result must be in the allowable range of mod results.
2963 if Lo_Right
= Hi_Right
2964 and then Lo_Right
/= 0
2966 if Lo_Right
> 0 then
2968 Hir
:= Lo_Right
- 1;
2970 else -- Lo_Right < 0
2971 Lor
:= Lo_Right
+ 1;
2980 -- For REM, if right operand is a positive constant, then
2981 -- result must be in the allowable range of mod results.
2985 if Lo_Right
= Hi_Right
2986 and then Lo_Right
/= 0
2989 Dval
: constant Uint
:= (abs Lo_Right
) - 1;
2992 -- The sign of the result depends on the sign of the
2993 -- dividend (but not on the sign of the divisor, hence
2994 -- the abs operation above).
3014 -- Attribute reference cases
3016 when N_Attribute_Reference
=>
3017 case Attribute_Name
(N
) is
3019 -- For Pos/Val attributes, we can refine the range using the
3020 -- possible range of values of the attribute expression
3022 when Name_Pos | Name_Val
=>
3023 Determine_Range
(First
(Expressions
(N
)), OK1
, Lor
, Hir
);
3025 -- For Length attribute, use the bounds of the corresponding
3026 -- index type to refine the range.
3030 Atyp
: Entity_Id
:= Etype
(Prefix
(N
));
3038 if Is_Access_Type
(Atyp
) then
3039 Atyp
:= Designated_Type
(Atyp
);
3042 -- For string literal, we know exact value
3044 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
3046 Lo
:= String_Literal_Length
(Atyp
);
3047 Hi
:= String_Literal_Length
(Atyp
);
3051 -- Otherwise check for expression given
3053 if No
(Expressions
(N
)) then
3057 UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
3060 Indx
:= First_Index
(Atyp
);
3061 for J
in 2 .. Inum
loop
3062 Indx
:= Next_Index
(Indx
);
3066 (Type_Low_Bound
(Etype
(Indx
)), OK1
, LL
, LU
);
3070 (Type_High_Bound
(Etype
(Indx
)), OK1
, UL
, UU
);
3074 -- The maximum value for Length is the biggest
3075 -- possible gap between the values of the bounds.
3076 -- But of course, this value cannot be negative.
3078 Hir
:= UI_Max
(Uint_0
, UU
- LL
);
3080 -- For constrained arrays, the minimum value for
3081 -- Length is taken from the actual value of the
3082 -- bounds, since the index will be exactly of
3085 if Is_Constrained
(Atyp
) then
3086 Lor
:= UI_Max
(Uint_0
, UL
- LU
);
3088 -- For an unconstrained array, the minimum value
3089 -- for length is always zero.
3098 -- No special handling for other attributes
3099 -- Probably more opportunities exist here ???
3106 -- For type conversion from one discrete type to another, we
3107 -- can refine the range using the converted value.
3109 when N_Type_Conversion
=>
3110 Determine_Range
(Expression
(N
), OK1
, Lor
, Hir
);
3112 -- Nothing special to do for all other expression kinds
3120 -- At this stage, if OK1 is true, then we know that the actual
3121 -- result of the computed expression is in the range Lor .. Hir.
3122 -- We can use this to restrict the possible range of results.
3126 -- If the refined value of the low bound is greater than the
3127 -- type high bound, then reset it to the more restrictive
3128 -- value. However, we do NOT do this for the case of a modular
3129 -- type where the possible upper bound on the value is above the
3130 -- base type high bound, because that means the result could wrap.
3133 and then not (Is_Modular_Integer_Type
(Typ
)
3134 and then Hir
> Hbound
)
3139 -- Similarly, if the refined value of the high bound is less
3140 -- than the value so far, then reset it to the more restrictive
3141 -- value. Again, we do not do this if the refined low bound is
3142 -- negative for a modular type, since this would wrap.
3145 and then not (Is_Modular_Integer_Type
(Typ
)
3146 and then Lor
< Uint_0
)
3152 -- Set cache entry for future call and we are all done
3154 Determine_Range_Cache_N
(Cindex
) := N
;
3155 Determine_Range_Cache_Lo
(Cindex
) := Lo
;
3156 Determine_Range_Cache_Hi
(Cindex
) := Hi
;
3159 -- If any exception occurs, it means that we have some bug in the compiler
3160 -- possibly triggered by a previous error, or by some unforseen peculiar
3161 -- occurrence. However, this is only an optimization attempt, so there is
3162 -- really no point in crashing the compiler. Instead we just decide, too
3163 -- bad, we can't figure out a range in this case after all.
3168 -- Debug flag K disables this behavior (useful for debugging)
3170 if Debug_Flag_K
then
3178 end Determine_Range
;
3180 ------------------------------------
3181 -- Discriminant_Checks_Suppressed --
3182 ------------------------------------
3184 function Discriminant_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3187 if Is_Unchecked_Union
(E
) then
3189 elsif Checks_May_Be_Suppressed
(E
) then
3190 return Is_Check_Suppressed
(E
, Discriminant_Check
);
3194 return Scope_Suppress
(Discriminant_Check
);
3195 end Discriminant_Checks_Suppressed
;
3197 --------------------------------
3198 -- Division_Checks_Suppressed --
3199 --------------------------------
3201 function Division_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3203 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
3204 return Is_Check_Suppressed
(E
, Division_Check
);
3206 return Scope_Suppress
(Division_Check
);
3208 end Division_Checks_Suppressed
;
3210 -----------------------------------
3211 -- Elaboration_Checks_Suppressed --
3212 -----------------------------------
3214 function Elaboration_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3217 if Kill_Elaboration_Checks
(E
) then
3219 elsif Checks_May_Be_Suppressed
(E
) then
3220 return Is_Check_Suppressed
(E
, Elaboration_Check
);
3224 return Scope_Suppress
(Elaboration_Check
);
3225 end Elaboration_Checks_Suppressed
;
3227 ---------------------------
3228 -- Enable_Overflow_Check --
3229 ---------------------------
3231 procedure Enable_Overflow_Check
(N
: Node_Id
) is
3232 Typ
: constant Entity_Id
:= Base_Type
(Etype
(N
));
3241 if Debug_Flag_CC
then
3242 w
("Enable_Overflow_Check for node ", Int
(N
));
3243 Write_Str
(" Source location = ");
3248 -- Nothing to do if the range of the result is known OK. We skip
3249 -- this for conversions, since the caller already did the check,
3250 -- and in any case the condition for deleting the check for a
3251 -- type conversion is different in any case.
3253 if Nkind
(N
) /= N_Type_Conversion
then
3254 Determine_Range
(N
, OK
, Lo
, Hi
);
3256 -- Note in the test below that we assume that if a bound of the
3257 -- range is equal to that of the type. That's not quite accurate
3258 -- but we do this for the following reasons:
3260 -- a) The way that Determine_Range works, it will typically report
3261 -- the bounds of the value as being equal to the bounds of the
3262 -- type, because it either can't tell anything more precise, or
3263 -- does not think it is worth the effort to be more precise.
3265 -- b) It is very unusual to have a situation in which this would
3266 -- generate an unnecessary overflow check (an example would be
3267 -- a subtype with a range 0 .. Integer'Last - 1 to which the
3268 -- literal value one is added.
3270 -- c) The alternative is a lot of special casing in this routine
3271 -- which would partially duplicate Determine_Range processing.
3274 and then Lo
> Expr_Value
(Type_Low_Bound
(Typ
))
3275 and then Hi
< Expr_Value
(Type_High_Bound
(Typ
))
3277 if Debug_Flag_CC
then
3278 w
("No overflow check required");
3285 -- If not in optimizing mode, set flag and we are done. We are also
3286 -- done (and just set the flag) if the type is not a discrete type,
3287 -- since it is not worth the effort to eliminate checks for other
3288 -- than discrete types. In addition, we take this same path if we
3289 -- have stored the maximum number of checks possible already (a
3290 -- very unlikely situation, but we do not want to blow up!)
3292 if Optimization_Level
= 0
3293 or else not Is_Discrete_Type
(Etype
(N
))
3294 or else Num_Saved_Checks
= Saved_Checks
'Last
3296 Set_Do_Overflow_Check
(N
, True);
3298 if Debug_Flag_CC
then
3299 w
("Optimization off");
3305 -- Otherwise evaluate and check the expression
3310 Target_Type
=> Empty
,
3316 if Debug_Flag_CC
then
3317 w
("Called Find_Check");
3321 w
(" Check_Num = ", Chk
);
3322 w
(" Ent = ", Int
(Ent
));
3323 Write_Str
(" Ofs = ");
3328 -- If check is not of form to optimize, then set flag and we are done
3331 Set_Do_Overflow_Check
(N
, True);
3335 -- If check is already performed, then return without setting flag
3338 if Debug_Flag_CC
then
3339 w
("Check suppressed!");
3345 -- Here we will make a new entry for the new check
3347 Set_Do_Overflow_Check
(N
, True);
3348 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
3349 Saved_Checks
(Num_Saved_Checks
) :=
3354 Target_Type
=> Empty
);
3356 if Debug_Flag_CC
then
3357 w
("Make new entry, check number = ", Num_Saved_Checks
);
3358 w
(" Entity = ", Int
(Ent
));
3359 Write_Str
(" Offset = ");
3361 w
(" Check_Type = O");
3362 w
(" Target_Type = Empty");
3365 -- If we get an exception, then something went wrong, probably because
3366 -- of an error in the structure of the tree due to an incorrect program.
3367 -- Or it may be a bug in the optimization circuit. In either case the
3368 -- safest thing is simply to set the check flag unconditionally.
3372 Set_Do_Overflow_Check
(N
, True);
3374 if Debug_Flag_CC
then
3375 w
(" exception occurred, overflow flag set");
3379 end Enable_Overflow_Check
;
3381 ------------------------
3382 -- Enable_Range_Check --
3383 ------------------------
3385 procedure Enable_Range_Check
(N
: Node_Id
) is
3394 -- Return if unchecked type conversion with range check killed.
3395 -- In this case we never set the flag (that's what Kill_Range_Check
3398 if Nkind
(N
) = N_Unchecked_Type_Conversion
3399 and then Kill_Range_Check
(N
)
3404 -- Debug trace output
3406 if Debug_Flag_CC
then
3407 w
("Enable_Range_Check for node ", Int
(N
));
3408 Write_Str
(" Source location = ");
3413 -- If not in optimizing mode, set flag and we are done. We are also
3414 -- done (and just set the flag) if the type is not a discrete type,
3415 -- since it is not worth the effort to eliminate checks for other
3416 -- than discrete types. In addition, we take this same path if we
3417 -- have stored the maximum number of checks possible already (a
3418 -- very unlikely situation, but we do not want to blow up!)
3420 if Optimization_Level
= 0
3421 or else No
(Etype
(N
))
3422 or else not Is_Discrete_Type
(Etype
(N
))
3423 or else Num_Saved_Checks
= Saved_Checks
'Last
3425 Set_Do_Range_Check
(N
, True);
3427 if Debug_Flag_CC
then
3428 w
("Optimization off");
3434 -- Otherwise find out the target type
3438 -- For assignment, use left side subtype
3440 if Nkind
(P
) = N_Assignment_Statement
3441 and then Expression
(P
) = N
3443 Ttyp
:= Etype
(Name
(P
));
3445 -- For indexed component, use subscript subtype
3447 elsif Nkind
(P
) = N_Indexed_Component
then
3454 Atyp
:= Etype
(Prefix
(P
));
3456 if Is_Access_Type
(Atyp
) then
3457 Atyp
:= Designated_Type
(Atyp
);
3459 -- If the prefix is an access to an unconstrained array,
3460 -- perform check unconditionally: it depends on the bounds
3461 -- of an object and we cannot currently recognize whether
3462 -- the test may be redundant.
3464 if not Is_Constrained
(Atyp
) then
3465 Set_Do_Range_Check
(N
, True);
3470 Indx
:= First_Index
(Atyp
);
3471 Subs
:= First
(Expressions
(P
));
3474 Ttyp
:= Etype
(Indx
);
3483 -- For now, ignore all other cases, they are not so interesting
3486 if Debug_Flag_CC
then
3487 w
(" target type not found, flag set");
3490 Set_Do_Range_Check
(N
, True);
3494 -- Evaluate and check the expression
3499 Target_Type
=> Ttyp
,
3505 if Debug_Flag_CC
then
3506 w
("Called Find_Check");
3507 w
("Target_Typ = ", Int
(Ttyp
));
3511 w
(" Check_Num = ", Chk
);
3512 w
(" Ent = ", Int
(Ent
));
3513 Write_Str
(" Ofs = ");
3518 -- If check is not of form to optimize, then set flag and we are done
3521 if Debug_Flag_CC
then
3522 w
(" expression not of optimizable type, flag set");
3525 Set_Do_Range_Check
(N
, True);
3529 -- If check is already performed, then return without setting flag
3532 if Debug_Flag_CC
then
3533 w
("Check suppressed!");
3539 -- Here we will make a new entry for the new check
3541 Set_Do_Range_Check
(N
, True);
3542 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
3543 Saved_Checks
(Num_Saved_Checks
) :=
3548 Target_Type
=> Ttyp
);
3550 if Debug_Flag_CC
then
3551 w
("Make new entry, check number = ", Num_Saved_Checks
);
3552 w
(" Entity = ", Int
(Ent
));
3553 Write_Str
(" Offset = ");
3555 w
(" Check_Type = R");
3556 w
(" Target_Type = ", Int
(Ttyp
));
3560 -- If we get an exception, then something went wrong, probably because
3561 -- of an error in the structure of the tree due to an incorrect program.
3562 -- Or it may be a bug in the optimization circuit. In either case the
3563 -- safest thing is simply to set the check flag unconditionally.
3567 Set_Do_Range_Check
(N
, True);
3569 if Debug_Flag_CC
then
3570 w
(" exception occurred, range flag set");
3574 end Enable_Range_Check
;
3580 procedure Ensure_Valid
(Expr
: Node_Id
; Holes_OK
: Boolean := False) is
3581 Typ
: constant Entity_Id
:= Etype
(Expr
);
3584 -- Ignore call if we are not doing any validity checking
3586 if not Validity_Checks_On
then
3589 -- Ignore call if range checks suppressed on entity in question
3591 elsif Is_Entity_Name
(Expr
)
3592 and then Range_Checks_Suppressed
(Entity
(Expr
))
3596 -- No check required if expression is from the expander, we assume
3597 -- the expander will generate whatever checks are needed. Note that
3598 -- this is not just an optimization, it avoids infinite recursions!
3600 -- Unchecked conversions must be checked, unless they are initialized
3601 -- scalar values, as in a component assignment in an init proc.
3603 -- In addition, we force a check if Force_Validity_Checks is set
3605 elsif not Comes_From_Source
(Expr
)
3606 and then not Force_Validity_Checks
3607 and then (Nkind
(Expr
) /= N_Unchecked_Type_Conversion
3608 or else Kill_Range_Check
(Expr
))
3612 -- No check required if expression is known to have valid value
3614 elsif Expr_Known_Valid
(Expr
) then
3617 -- No check required if checks off
3619 elsif Range_Checks_Suppressed
(Typ
) then
3622 -- Ignore case of enumeration with holes where the flag is set not
3623 -- to worry about holes, since no special validity check is needed
3625 elsif Is_Enumeration_Type
(Typ
)
3626 and then Has_Non_Standard_Rep
(Typ
)
3631 -- No check required on the left-hand side of an assignment.
3633 elsif Nkind
(Parent
(Expr
)) = N_Assignment_Statement
3634 and then Expr
= Name
(Parent
(Expr
))
3638 -- An annoying special case. If this is an out parameter of a scalar
3639 -- type, then the value is not going to be accessed, therefore it is
3640 -- inappropriate to do any validity check at the call site.
3643 -- Only need to worry about scalar types
3645 if Is_Scalar_Type
(Typ
) then
3655 -- Find actual argument (which may be a parameter association)
3656 -- and the parent of the actual argument (the call statement)
3661 if Nkind
(P
) = N_Parameter_Association
then
3666 -- Only need to worry if we are argument of a procedure
3667 -- call since functions don't have out parameters. If this
3668 -- is an indirect or dispatching call, get signature from
3669 -- the subprogram type.
3671 if Nkind
(P
) = N_Procedure_Call_Statement
then
3672 L
:= Parameter_Associations
(P
);
3674 if Is_Entity_Name
(Name
(P
)) then
3675 E
:= Entity
(Name
(P
));
3677 pragma Assert
(Nkind
(Name
(P
)) = N_Explicit_Dereference
);
3678 E
:= Etype
(Name
(P
));
3681 -- Only need to worry if there are indeed actuals, and
3682 -- if this could be a procedure call, otherwise we cannot
3683 -- get a match (either we are not an argument, or the
3684 -- mode of the formal is not OUT). This test also filters
3685 -- out the generic case.
3687 if Is_Non_Empty_List
(L
)
3688 and then Is_Subprogram
(E
)
3690 -- This is the loop through parameters, looking to
3691 -- see if there is an OUT parameter for which we are
3694 F
:= First_Formal
(E
);
3697 while Present
(F
) loop
3698 if Ekind
(F
) = E_Out_Parameter
and then A
= N
then
3711 -- If we fall through, a validity check is required. Note that it would
3712 -- not be good to set Do_Range_Check, even in contexts where this is
3713 -- permissible, since this flag causes checking against the target type,
3714 -- not the source type in contexts such as assignments
3716 Insert_Valid_Check
(Expr
);
3719 ----------------------
3720 -- Expr_Known_Valid --
3721 ----------------------
3723 function Expr_Known_Valid
(Expr
: Node_Id
) return Boolean is
3724 Typ
: constant Entity_Id
:= Etype
(Expr
);
3727 -- Non-scalar types are always considered valid, since they never
3728 -- give rise to the issues of erroneous or bounded error behavior
3729 -- that are the concern. In formal reference manual terms the
3730 -- notion of validity only applies to scalar types. Note that
3731 -- even when packed arrays are represented using modular types,
3732 -- they are still arrays semantically, so they are also always
3733 -- valid (in particular, the unused bits can be random rubbish
3734 -- without affecting the validity of the array value).
3736 if not Is_Scalar_Type
(Typ
) or else Is_Packed_Array_Type
(Typ
) then
3739 -- If no validity checking, then everything is considered valid
3741 elsif not Validity_Checks_On
then
3744 -- Floating-point types are considered valid unless floating-point
3745 -- validity checks have been specifically turned on.
3747 elsif Is_Floating_Point_Type
(Typ
)
3748 and then not Validity_Check_Floating_Point
3752 -- If the expression is the value of an object that is known to
3753 -- be valid, then clearly the expression value itself is valid.
3755 elsif Is_Entity_Name
(Expr
)
3756 and then Is_Known_Valid
(Entity
(Expr
))
3760 -- If the type is one for which all values are known valid, then
3761 -- we are sure that the value is valid except in the slightly odd
3762 -- case where the expression is a reference to a variable whose size
3763 -- has been explicitly set to a value greater than the object size.
3765 elsif Is_Known_Valid
(Typ
) then
3766 if Is_Entity_Name
(Expr
)
3767 and then Ekind
(Entity
(Expr
)) = E_Variable
3768 and then Esize
(Entity
(Expr
)) > Esize
(Typ
)
3775 -- Integer and character literals always have valid values, where
3776 -- appropriate these will be range checked in any case.
3778 elsif Nkind
(Expr
) = N_Integer_Literal
3780 Nkind
(Expr
) = N_Character_Literal
3784 -- If we have a type conversion or a qualification of a known valid
3785 -- value, then the result will always be valid.
3787 elsif Nkind
(Expr
) = N_Type_Conversion
3789 Nkind
(Expr
) = N_Qualified_Expression
3791 return Expr_Known_Valid
(Expression
(Expr
));
3793 -- The result of any function call or operator is always considered
3794 -- valid, since we assume the necessary checks are done by the call.
3796 elsif Nkind
(Expr
) in N_Binary_Op
3798 Nkind
(Expr
) in N_Unary_Op
3800 Nkind
(Expr
) = N_Function_Call
3804 -- For all other cases, we do not know the expression is valid
3809 end Expr_Known_Valid
;
3815 procedure Find_Check
3817 Check_Type
: Character;
3818 Target_Type
: Entity_Id
;
3819 Entry_OK
: out Boolean;
3820 Check_Num
: out Nat
;
3821 Ent
: out Entity_Id
;
3824 function Within_Range_Of
3825 (Target_Type
: Entity_Id
;
3826 Check_Type
: Entity_Id
) return Boolean;
3827 -- Given a requirement for checking a range against Target_Type, and
3828 -- and a range Check_Type against which a check has already been made,
3829 -- determines if the check against check type is sufficient to ensure
3830 -- that no check against Target_Type is required.
3832 ---------------------
3833 -- Within_Range_Of --
3834 ---------------------
3836 function Within_Range_Of
3837 (Target_Type
: Entity_Id
;
3838 Check_Type
: Entity_Id
) return Boolean
3841 if Target_Type
= Check_Type
then
3846 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Type
);
3847 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Type
);
3848 Clo
: constant Node_Id
:= Type_Low_Bound
(Check_Type
);
3849 Chi
: constant Node_Id
:= Type_High_Bound
(Check_Type
);
3853 or else (Compile_Time_Known_Value
(Tlo
)
3855 Compile_Time_Known_Value
(Clo
)
3857 Expr_Value
(Clo
) >= Expr_Value
(Tlo
)))
3860 or else (Compile_Time_Known_Value
(Thi
)
3862 Compile_Time_Known_Value
(Chi
)
3864 Expr_Value
(Chi
) <= Expr_Value
(Clo
)))
3872 end Within_Range_Of
;
3874 -- Start of processing for Find_Check
3877 -- Establish default, to avoid warnings from GCC.
3881 -- Case of expression is simple entity reference
3883 if Is_Entity_Name
(Expr
) then
3884 Ent
:= Entity
(Expr
);
3887 -- Case of expression is entity + known constant
3889 elsif Nkind
(Expr
) = N_Op_Add
3890 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
3891 and then Is_Entity_Name
(Left_Opnd
(Expr
))
3893 Ent
:= Entity
(Left_Opnd
(Expr
));
3894 Ofs
:= Expr_Value
(Right_Opnd
(Expr
));
3896 -- Case of expression is entity - known constant
3898 elsif Nkind
(Expr
) = N_Op_Subtract
3899 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
3900 and then Is_Entity_Name
(Left_Opnd
(Expr
))
3902 Ent
:= Entity
(Left_Opnd
(Expr
));
3903 Ofs
:= UI_Negate
(Expr_Value
(Right_Opnd
(Expr
)));
3905 -- Any other expression is not of the right form
3914 -- Come here with expression of appropriate form, check if
3915 -- entity is an appropriate one for our purposes.
3917 if (Ekind
(Ent
) = E_Variable
3919 Ekind
(Ent
) = E_Constant
3921 Ekind
(Ent
) = E_Loop_Parameter
3923 Ekind
(Ent
) = E_In_Parameter
)
3924 and then not Is_Library_Level_Entity
(Ent
)
3932 -- See if there is matching check already
3934 for J
in reverse 1 .. Num_Saved_Checks
loop
3936 SC
: Saved_Check
renames Saved_Checks
(J
);
3939 if SC
.Killed
= False
3940 and then SC
.Entity
= Ent
3941 and then SC
.Offset
= Ofs
3942 and then SC
.Check_Type
= Check_Type
3943 and then Within_Range_Of
(Target_Type
, SC
.Target_Type
)
3951 -- If we fall through entry was not found
3957 ---------------------------------
3958 -- Generate_Discriminant_Check --
3959 ---------------------------------
3961 -- Note: the code for this procedure is derived from the
3962 -- emit_discriminant_check routine a-trans.c v1.659.
3964 procedure Generate_Discriminant_Check
(N
: Node_Id
) is
3965 Loc
: constant Source_Ptr
:= Sloc
(N
);
3966 Pref
: constant Node_Id
:= Prefix
(N
);
3967 Sel
: constant Node_Id
:= Selector_Name
(N
);
3969 Orig_Comp
: constant Entity_Id
:=
3970 Original_Record_Component
(Entity
(Sel
));
3971 -- The original component to be checked
3973 Discr_Fct
: constant Entity_Id
:=
3974 Discriminant_Checking_Func
(Orig_Comp
);
3975 -- The discriminant checking function
3978 -- One discriminant to be checked in the type
3980 Real_Discr
: Entity_Id
;
3981 -- Actual discriminant in the call
3983 Pref_Type
: Entity_Id
;
3984 -- Type of relevant prefix (ignoring private/access stuff)
3987 -- List of arguments for function call
3990 -- Keep track of the formal corresponding to the actual we build
3991 -- for each discriminant, in order to be able to perform the
3992 -- necessary type conversions.
3995 -- Selected component reference for checking function argument
3998 Pref_Type
:= Etype
(Pref
);
4000 -- Force evaluation of the prefix, so that it does not get evaluated
4001 -- twice (once for the check, once for the actual reference). Such a
4002 -- double evaluation is always a potential source of inefficiency,
4003 -- and is functionally incorrect in the volatile case, or when the
4004 -- prefix may have side-effects. An entity or a component of an
4005 -- entity requires no evaluation.
4007 if Is_Entity_Name
(Pref
) then
4008 if Treat_As_Volatile
(Entity
(Pref
)) then
4009 Force_Evaluation
(Pref
, Name_Req
=> True);
4012 elsif Treat_As_Volatile
(Etype
(Pref
)) then
4013 Force_Evaluation
(Pref
, Name_Req
=> True);
4015 elsif Nkind
(Pref
) = N_Selected_Component
4016 and then Is_Entity_Name
(Prefix
(Pref
))
4021 Force_Evaluation
(Pref
, Name_Req
=> True);
4024 -- For a tagged type, use the scope of the original component to
4025 -- obtain the type, because ???
4027 if Is_Tagged_Type
(Scope
(Orig_Comp
)) then
4028 Pref_Type
:= Scope
(Orig_Comp
);
4030 -- For an untagged derived type, use the discriminants of the
4031 -- parent which have been renamed in the derivation, possibly
4032 -- by a one-to-many discriminant constraint.
4033 -- For non-tagged type, initially get the Etype of the prefix
4036 if Is_Derived_Type
(Pref_Type
)
4037 and then Number_Discriminants
(Pref_Type
) /=
4038 Number_Discriminants
(Etype
(Base_Type
(Pref_Type
)))
4040 Pref_Type
:= Etype
(Base_Type
(Pref_Type
));
4044 -- We definitely should have a checking function, This routine should
4045 -- not be called if no discriminant checking function is present.
4047 pragma Assert
(Present
(Discr_Fct
));
4049 -- Create the list of the actual parameters for the call. This list
4050 -- is the list of the discriminant fields of the record expression to
4051 -- be discriminant checked.
4054 Formal
:= First_Formal
(Discr_Fct
);
4055 Discr
:= First_Discriminant
(Pref_Type
);
4056 while Present
(Discr
) loop
4058 -- If we have a corresponding discriminant field, and a parent
4059 -- subtype is present, then we want to use the corresponding
4060 -- discriminant since this is the one with the useful value.
4062 if Present
(Corresponding_Discriminant
(Discr
))
4063 and then Ekind
(Pref_Type
) = E_Record_Type
4064 and then Present
(Parent_Subtype
(Pref_Type
))
4066 Real_Discr
:= Corresponding_Discriminant
(Discr
);
4068 Real_Discr
:= Discr
;
4071 -- Construct the reference to the discriminant
4074 Make_Selected_Component
(Loc
,
4076 Unchecked_Convert_To
(Pref_Type
,
4077 Duplicate_Subexpr
(Pref
)),
4078 Selector_Name
=> New_Occurrence_Of
(Real_Discr
, Loc
));
4080 -- Manually analyze and resolve this selected component. We really
4081 -- want it just as it appears above, and do not want the expander
4082 -- playing discriminal games etc with this reference. Then we
4083 -- append the argument to the list we are gathering.
4085 Set_Etype
(Scomp
, Etype
(Real_Discr
));
4086 Set_Analyzed
(Scomp
, True);
4087 Append_To
(Args
, Convert_To
(Etype
(Formal
), Scomp
));
4089 Next_Formal_With_Extras
(Formal
);
4090 Next_Discriminant
(Discr
);
4093 -- Now build and insert the call
4096 Make_Raise_Constraint_Error
(Loc
,
4098 Make_Function_Call
(Loc
,
4099 Name
=> New_Occurrence_Of
(Discr_Fct
, Loc
),
4100 Parameter_Associations
=> Args
),
4101 Reason
=> CE_Discriminant_Check_Failed
));
4102 end Generate_Discriminant_Check
;
4104 ---------------------------
4105 -- Generate_Index_Checks --
4106 ---------------------------
4108 procedure Generate_Index_Checks
(N
: Node_Id
) is
4109 Loc
: constant Source_Ptr
:= Sloc
(N
);
4110 A
: constant Node_Id
:= Prefix
(N
);
4116 Sub
:= First
(Expressions
(N
));
4118 while Present
(Sub
) loop
4119 if Do_Range_Check
(Sub
) then
4120 Set_Do_Range_Check
(Sub
, False);
4122 -- Force evaluation except for the case of a simple name of
4123 -- a non-volatile entity.
4125 if not Is_Entity_Name
(Sub
)
4126 or else Treat_As_Volatile
(Entity
(Sub
))
4128 Force_Evaluation
(Sub
);
4131 -- Generate a raise of constraint error with the appropriate
4132 -- reason and a condition of the form:
4134 -- Base_Type(Sub) not in array'range (subscript)
4136 -- Note that the reason we generate the conversion to the
4137 -- base type here is that we definitely want the range check
4138 -- to take place, even if it looks like the subtype is OK.
4139 -- Optimization considerations that allow us to omit the
4140 -- check have already been taken into account in the setting
4141 -- of the Do_Range_Check flag earlier on.
4146 Num
:= New_List
(Make_Integer_Literal
(Loc
, Ind
));
4150 Make_Raise_Constraint_Error
(Loc
,
4154 Convert_To
(Base_Type
(Etype
(Sub
)),
4155 Duplicate_Subexpr_Move_Checks
(Sub
)),
4157 Make_Attribute_Reference
(Loc
,
4158 Prefix
=> Duplicate_Subexpr_Move_Checks
(A
),
4159 Attribute_Name
=> Name_Range
,
4160 Expressions
=> Num
)),
4161 Reason
=> CE_Index_Check_Failed
));
4167 end Generate_Index_Checks
;
4169 --------------------------
4170 -- Generate_Range_Check --
4171 --------------------------
4173 procedure Generate_Range_Check
4175 Target_Type
: Entity_Id
;
4176 Reason
: RT_Exception_Code
)
4178 Loc
: constant Source_Ptr
:= Sloc
(N
);
4179 Source_Type
: constant Entity_Id
:= Etype
(N
);
4180 Source_Base_Type
: constant Entity_Id
:= Base_Type
(Source_Type
);
4181 Target_Base_Type
: constant Entity_Id
:= Base_Type
(Target_Type
);
4184 -- First special case, if the source type is already within the
4185 -- range of the target type, then no check is needed (probably we
4186 -- should have stopped Do_Range_Check from being set in the first
4187 -- place, but better late than later in preventing junk code!
4189 -- We do NOT apply this if the source node is a literal, since in
4190 -- this case the literal has already been labeled as having the
4191 -- subtype of the target.
4193 if In_Subrange_Of
(Source_Type
, Target_Type
)
4195 (Nkind
(N
) = N_Integer_Literal
4197 Nkind
(N
) = N_Real_Literal
4199 Nkind
(N
) = N_Character_Literal
4202 and then Ekind
(Entity
(N
)) = E_Enumeration_Literal
))
4207 -- We need a check, so force evaluation of the node, so that it does
4208 -- not get evaluated twice (once for the check, once for the actual
4209 -- reference). Such a double evaluation is always a potential source
4210 -- of inefficiency, and is functionally incorrect in the volatile case.
4212 if not Is_Entity_Name
(N
)
4213 or else Treat_As_Volatile
(Entity
(N
))
4215 Force_Evaluation
(N
);
4218 -- The easiest case is when Source_Base_Type and Target_Base_Type
4219 -- are the same since in this case we can simply do a direct
4220 -- check of the value of N against the bounds of Target_Type.
4222 -- [constraint_error when N not in Target_Type]
4224 -- Note: this is by far the most common case, for example all cases of
4225 -- checks on the RHS of assignments are in this category, but not all
4226 -- cases are like this. Notably conversions can involve two types.
4228 if Source_Base_Type
= Target_Base_Type
then
4230 Make_Raise_Constraint_Error
(Loc
,
4233 Left_Opnd
=> Duplicate_Subexpr
(N
),
4234 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
4237 -- Next test for the case where the target type is within the bounds
4238 -- of the base type of the source type, since in this case we can
4239 -- simply convert these bounds to the base type of T to do the test.
4241 -- [constraint_error when N not in
4242 -- Source_Base_Type (Target_Type'First)
4244 -- Source_Base_Type(Target_Type'Last))]
4246 -- The conversions will always work and need no check.
4248 elsif In_Subrange_Of
(Target_Type
, Source_Base_Type
) then
4250 Make_Raise_Constraint_Error
(Loc
,
4253 Left_Opnd
=> Duplicate_Subexpr
(N
),
4258 Convert_To
(Source_Base_Type
,
4259 Make_Attribute_Reference
(Loc
,
4261 New_Occurrence_Of
(Target_Type
, Loc
),
4262 Attribute_Name
=> Name_First
)),
4265 Convert_To
(Source_Base_Type
,
4266 Make_Attribute_Reference
(Loc
,
4268 New_Occurrence_Of
(Target_Type
, Loc
),
4269 Attribute_Name
=> Name_Last
)))),
4272 -- Note that at this stage we now that the Target_Base_Type is
4273 -- not in the range of the Source_Base_Type (since even the
4274 -- Target_Type itself is not in this range). It could still be
4275 -- the case that the Source_Type is in range of the target base
4276 -- type, since we have not checked that case.
4278 -- If that is the case, we can freely convert the source to the
4279 -- target, and then test the target result against the bounds.
4281 elsif In_Subrange_Of
(Source_Type
, Target_Base_Type
) then
4283 -- We make a temporary to hold the value of the converted
4284 -- value (converted to the base type), and then we will
4285 -- do the test against this temporary.
4287 -- Tnn : constant Target_Base_Type := Target_Base_Type (N);
4288 -- [constraint_error when Tnn not in Target_Type]
4290 -- Then the conversion itself is replaced by an occurrence of Tnn
4293 Tnn
: constant Entity_Id
:=
4294 Make_Defining_Identifier
(Loc
,
4295 Chars
=> New_Internal_Name
('T'));
4298 Insert_Actions
(N
, New_List
(
4299 Make_Object_Declaration
(Loc
,
4300 Defining_Identifier
=> Tnn
,
4301 Object_Definition
=>
4302 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4303 Constant_Present
=> True,
4305 Make_Type_Conversion
(Loc
,
4306 Subtype_Mark
=> New_Occurrence_Of
(Target_Base_Type
, Loc
),
4307 Expression
=> Duplicate_Subexpr
(N
))),
4309 Make_Raise_Constraint_Error
(Loc
,
4312 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
4313 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
4315 Reason
=> Reason
)));
4317 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
4320 -- At this stage, we know that we have two scalar types, which are
4321 -- directly convertible, and where neither scalar type has a base
4322 -- range that is in the range of the other scalar type.
4324 -- The only way this can happen is with a signed and unsigned type.
4325 -- So test for these two cases:
4328 -- Case of the source is unsigned and the target is signed
4330 if Is_Unsigned_Type
(Source_Base_Type
)
4331 and then not Is_Unsigned_Type
(Target_Base_Type
)
4333 -- If the source is unsigned and the target is signed, then we
4334 -- know that the source is not shorter than the target (otherwise
4335 -- the source base type would be in the target base type range).
4337 -- In other words, the unsigned type is either the same size
4338 -- as the target, or it is larger. It cannot be smaller.
4341 (Esize
(Source_Base_Type
) >= Esize
(Target_Base_Type
));
4343 -- We only need to check the low bound if the low bound of the
4344 -- target type is non-negative. If the low bound of the target
4345 -- type is negative, then we know that we will fit fine.
4347 -- If the high bound of the target type is negative, then we
4348 -- know we have a constraint error, since we can't possibly
4349 -- have a negative source.
4351 -- With these two checks out of the way, we can do the check
4352 -- using the source type safely
4354 -- This is definitely the most annoying case!
4356 -- [constraint_error
4357 -- when (Target_Type'First >= 0
4359 -- N < Source_Base_Type (Target_Type'First))
4360 -- or else Target_Type'Last < 0
4361 -- or else N > Source_Base_Type (Target_Type'Last)];
4363 -- We turn off all checks since we know that the conversions
4364 -- will work fine, given the guards for negative values.
4367 Make_Raise_Constraint_Error
(Loc
,
4373 Left_Opnd
=> Make_Op_Ge
(Loc
,
4375 Make_Attribute_Reference
(Loc
,
4377 New_Occurrence_Of
(Target_Type
, Loc
),
4378 Attribute_Name
=> Name_First
),
4379 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
4383 Left_Opnd
=> Duplicate_Subexpr
(N
),
4385 Convert_To
(Source_Base_Type
,
4386 Make_Attribute_Reference
(Loc
,
4388 New_Occurrence_Of
(Target_Type
, Loc
),
4389 Attribute_Name
=> Name_First
)))),
4394 Make_Attribute_Reference
(Loc
,
4395 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
4396 Attribute_Name
=> Name_Last
),
4397 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
))),
4401 Left_Opnd
=> Duplicate_Subexpr
(N
),
4403 Convert_To
(Source_Base_Type
,
4404 Make_Attribute_Reference
(Loc
,
4405 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
4406 Attribute_Name
=> Name_Last
)))),
4409 Suppress
=> All_Checks
);
4411 -- Only remaining possibility is that the source is signed and
4412 -- the target is unsigned
4415 pragma Assert
(not Is_Unsigned_Type
(Source_Base_Type
)
4416 and then Is_Unsigned_Type
(Target_Base_Type
));
4418 -- If the source is signed and the target is unsigned, then
4419 -- we know that the target is not shorter than the source
4420 -- (otherwise the target base type would be in the source
4421 -- base type range).
4423 -- In other words, the unsigned type is either the same size
4424 -- as the target, or it is larger. It cannot be smaller.
4426 -- Clearly we have an error if the source value is negative
4427 -- since no unsigned type can have negative values. If the
4428 -- source type is non-negative, then the check can be done
4429 -- using the target type.
4431 -- Tnn : constant Target_Base_Type (N) := Target_Type;
4433 -- [constraint_error
4434 -- when N < 0 or else Tnn not in Target_Type];
4436 -- We turn off all checks for the conversion of N to the
4437 -- target base type, since we generate the explicit check
4438 -- to ensure that the value is non-negative
4441 Tnn
: constant Entity_Id
:=
4442 Make_Defining_Identifier
(Loc
,
4443 Chars
=> New_Internal_Name
('T'));
4446 Insert_Actions
(N
, New_List
(
4447 Make_Object_Declaration
(Loc
,
4448 Defining_Identifier
=> Tnn
,
4449 Object_Definition
=>
4450 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4451 Constant_Present
=> True,
4453 Make_Type_Conversion
(Loc
,
4455 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4456 Expression
=> Duplicate_Subexpr
(N
))),
4458 Make_Raise_Constraint_Error
(Loc
,
4463 Left_Opnd
=> Duplicate_Subexpr
(N
),
4464 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
4468 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
4470 New_Occurrence_Of
(Target_Type
, Loc
))),
4473 Suppress
=> All_Checks
);
4475 -- Set the Etype explicitly, because Insert_Actions may
4476 -- have placed the declaration in the freeze list for an
4477 -- enclosing construct, and thus it is not analyzed yet.
4479 Set_Etype
(Tnn
, Target_Base_Type
);
4480 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
4484 end Generate_Range_Check
;
4486 ---------------------
4487 -- Get_Discriminal --
4488 ---------------------
4490 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
is
4491 Loc
: constant Source_Ptr
:= Sloc
(E
);
4496 -- The entity E is the type of a private component of the protected
4497 -- type, or the type of a renaming of that component within a protected
4498 -- operation of that type.
4502 if Ekind
(Sc
) /= E_Protected_Type
then
4505 if Ekind
(Sc
) /= E_Protected_Type
then
4510 D
:= First_Discriminant
(Sc
);
4513 and then Chars
(D
) /= Chars
(Bound
)
4515 Next_Discriminant
(D
);
4518 return New_Occurrence_Of
(Discriminal
(D
), Loc
);
4519 end Get_Discriminal
;
4525 function Guard_Access
4528 Ck_Node
: Node_Id
) return Node_Id
4531 if Nkind
(Cond
) = N_Or_Else
then
4532 Set_Paren_Count
(Cond
, 1);
4535 if Nkind
(Ck_Node
) = N_Allocator
then
4542 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
4543 Right_Opnd
=> Make_Null
(Loc
)),
4544 Right_Opnd
=> Cond
);
4548 -----------------------------
4549 -- Index_Checks_Suppressed --
4550 -----------------------------
4552 function Index_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4554 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4555 return Is_Check_Suppressed
(E
, Index_Check
);
4557 return Scope_Suppress
(Index_Check
);
4559 end Index_Checks_Suppressed
;
4565 procedure Initialize
is
4567 for J
in Determine_Range_Cache_N
'Range loop
4568 Determine_Range_Cache_N
(J
) := Empty
;
4572 -------------------------
4573 -- Insert_Range_Checks --
4574 -------------------------
4576 procedure Insert_Range_Checks
4577 (Checks
: Check_Result
;
4579 Suppress_Typ
: Entity_Id
;
4580 Static_Sloc
: Source_Ptr
:= No_Location
;
4581 Flag_Node
: Node_Id
:= Empty
;
4582 Do_Before
: Boolean := False)
4584 Internal_Flag_Node
: Node_Id
:= Flag_Node
;
4585 Internal_Static_Sloc
: Source_Ptr
:= Static_Sloc
;
4587 Check_Node
: Node_Id
;
4588 Checks_On
: constant Boolean :=
4589 (not Index_Checks_Suppressed
(Suppress_Typ
))
4591 (not Range_Checks_Suppressed
(Suppress_Typ
));
4594 -- For now we just return if Checks_On is false, however this should
4595 -- be enhanced to check for an always True value in the condition
4596 -- and to generate a compilation warning???
4598 if not Expander_Active
or else not Checks_On
then
4602 if Static_Sloc
= No_Location
then
4603 Internal_Static_Sloc
:= Sloc
(Node
);
4606 if No
(Flag_Node
) then
4607 Internal_Flag_Node
:= Node
;
4610 for J
in 1 .. 2 loop
4611 exit when No
(Checks
(J
));
4613 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
4614 and then Present
(Condition
(Checks
(J
)))
4616 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
4617 Check_Node
:= Checks
(J
);
4618 Mark_Rewrite_Insertion
(Check_Node
);
4621 Insert_Before_And_Analyze
(Node
, Check_Node
);
4623 Insert_After_And_Analyze
(Node
, Check_Node
);
4626 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
4631 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
4632 Reason
=> CE_Range_Check_Failed
);
4633 Mark_Rewrite_Insertion
(Check_Node
);
4636 Insert_Before_And_Analyze
(Node
, Check_Node
);
4638 Insert_After_And_Analyze
(Node
, Check_Node
);
4642 end Insert_Range_Checks
;
4644 ------------------------
4645 -- Insert_Valid_Check --
4646 ------------------------
4648 procedure Insert_Valid_Check
(Expr
: Node_Id
) is
4649 Loc
: constant Source_Ptr
:= Sloc
(Expr
);
4653 -- Do not insert if checks off, or if not checking validity
4655 if Range_Checks_Suppressed
(Etype
(Expr
))
4656 or else (not Validity_Checks_On
)
4661 -- If we have a checked conversion, then validity check applies to
4662 -- the expression inside the conversion, not the result, since if
4663 -- the expression inside is valid, then so is the conversion result.
4666 while Nkind
(Exp
) = N_Type_Conversion
loop
4667 Exp
:= Expression
(Exp
);
4670 -- Insert the validity check. Note that we do this with validity
4671 -- checks turned off, to avoid recursion, we do not want validity
4672 -- checks on the validity checking code itself!
4674 Validity_Checks_On
:= False;
4677 Make_Raise_Constraint_Error
(Loc
,
4681 Make_Attribute_Reference
(Loc
,
4683 Duplicate_Subexpr_No_Checks
(Exp
, Name_Req
=> True),
4684 Attribute_Name
=> Name_Valid
)),
4685 Reason
=> CE_Invalid_Data
),
4686 Suppress
=> All_Checks
);
4687 Validity_Checks_On
:= True;
4688 end Insert_Valid_Check
;
4690 ----------------------------------
4691 -- Install_Null_Excluding_Check --
4692 ----------------------------------
4694 procedure Install_Null_Excluding_Check
(N
: Node_Id
) is
4695 Loc
: constant Source_Ptr
:= Sloc
(N
);
4696 Etyp
: constant Entity_Id
:= Etype
(N
);
4699 pragma Assert
(Is_Access_Type
(Etyp
));
4701 -- Don't need access check if: 1) we are analyzing a generic, 2) it is
4702 -- known to be non-null, or 3) the check was suppressed on the type
4705 or else Access_Checks_Suppressed
(Etyp
)
4709 -- Otherwise install access check
4713 Make_Raise_Constraint_Error
(Loc
,
4716 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(N
),
4717 Right_Opnd
=> Make_Null
(Loc
)),
4718 Reason
=> CE_Access_Check_Failed
));
4720 end Install_Null_Excluding_Check
;
4722 --------------------------
4723 -- Install_Static_Check --
4724 --------------------------
4726 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
) is
4727 Stat
: constant Boolean := Is_Static_Expression
(R_Cno
);
4728 Typ
: constant Entity_Id
:= Etype
(R_Cno
);
4732 Make_Raise_Constraint_Error
(Loc
,
4733 Reason
=> CE_Range_Check_Failed
));
4734 Set_Analyzed
(R_Cno
);
4735 Set_Etype
(R_Cno
, Typ
);
4736 Set_Raises_Constraint_Error
(R_Cno
);
4737 Set_Is_Static_Expression
(R_Cno
, Stat
);
4738 end Install_Static_Check
;
4740 ---------------------
4741 -- Kill_All_Checks --
4742 ---------------------
4744 procedure Kill_All_Checks
is
4746 if Debug_Flag_CC
then
4747 w
("Kill_All_Checks");
4750 -- We reset the number of saved checks to zero, and also modify
4751 -- all stack entries for statement ranges to indicate that the
4752 -- number of checks at each level is now zero.
4754 Num_Saved_Checks
:= 0;
4756 for J
in 1 .. Saved_Checks_TOS
loop
4757 Saved_Checks_Stack
(J
) := 0;
4759 end Kill_All_Checks
;
4765 procedure Kill_Checks
(V
: Entity_Id
) is
4767 if Debug_Flag_CC
then
4768 w
("Kill_Checks for entity", Int
(V
));
4771 for J
in 1 .. Num_Saved_Checks
loop
4772 if Saved_Checks
(J
).Entity
= V
then
4773 if Debug_Flag_CC
then
4774 w
(" Checks killed for saved check ", J
);
4777 Saved_Checks
(J
).Killed
:= True;
4782 ------------------------------
4783 -- Length_Checks_Suppressed --
4784 ------------------------------
4786 function Length_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4788 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4789 return Is_Check_Suppressed
(E
, Length_Check
);
4791 return Scope_Suppress
(Length_Check
);
4793 end Length_Checks_Suppressed
;
4795 --------------------------------
4796 -- Overflow_Checks_Suppressed --
4797 --------------------------------
4799 function Overflow_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4801 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4802 return Is_Check_Suppressed
(E
, Overflow_Check
);
4804 return Scope_Suppress
(Overflow_Check
);
4806 end Overflow_Checks_Suppressed
;
4812 function Range_Check
4814 Target_Typ
: Entity_Id
;
4815 Source_Typ
: Entity_Id
:= Empty
;
4816 Warn_Node
: Node_Id
:= Empty
) return Check_Result
4819 return Selected_Range_Checks
4820 (Ck_Node
, Target_Typ
, Source_Typ
, Warn_Node
);
4823 -----------------------------
4824 -- Range_Checks_Suppressed --
4825 -----------------------------
4827 function Range_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4831 -- Note: for now we always suppress range checks on Vax float types,
4832 -- since Gigi does not know how to generate these checks.
4834 if Vax_Float
(E
) then
4836 elsif Kill_Range_Checks
(E
) then
4838 elsif Checks_May_Be_Suppressed
(E
) then
4839 return Is_Check_Suppressed
(E
, Range_Check
);
4843 return Scope_Suppress
(Range_Check
);
4844 end Range_Checks_Suppressed
;
4850 procedure Remove_Checks
(Expr
: Node_Id
) is
4851 Discard
: Traverse_Result
;
4852 pragma Warnings
(Off
, Discard
);
4854 function Process
(N
: Node_Id
) return Traverse_Result
;
4855 -- Process a single node during the traversal
4857 function Traverse
is new Traverse_Func
(Process
);
4858 -- The traversal function itself
4864 function Process
(N
: Node_Id
) return Traverse_Result
is
4866 if Nkind
(N
) not in N_Subexpr
then
4870 Set_Do_Range_Check
(N
, False);
4874 Discard
:= Traverse
(Left_Opnd
(N
));
4877 when N_Attribute_Reference
=>
4878 Set_Do_Overflow_Check
(N
, False);
4880 when N_Function_Call
=>
4881 Set_Do_Tag_Check
(N
, False);
4884 Set_Do_Overflow_Check
(N
, False);
4888 Set_Do_Division_Check
(N
, False);
4891 Set_Do_Length_Check
(N
, False);
4894 Set_Do_Division_Check
(N
, False);
4897 Set_Do_Length_Check
(N
, False);
4900 Set_Do_Division_Check
(N
, False);
4903 Set_Do_Length_Check
(N
, False);
4910 Discard
:= Traverse
(Left_Opnd
(N
));
4913 when N_Selected_Component
=>
4914 Set_Do_Discriminant_Check
(N
, False);
4916 when N_Type_Conversion
=>
4917 Set_Do_Length_Check
(N
, False);
4918 Set_Do_Tag_Check
(N
, False);
4919 Set_Do_Overflow_Check
(N
, False);
4928 -- Start of processing for Remove_Checks
4931 Discard
:= Traverse
(Expr
);
4934 ----------------------------
4935 -- Selected_Length_Checks --
4936 ----------------------------
4938 function Selected_Length_Checks
4940 Target_Typ
: Entity_Id
;
4941 Source_Typ
: Entity_Id
;
4942 Warn_Node
: Node_Id
) return Check_Result
4944 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
4947 Expr_Actual
: Node_Id
;
4949 Cond
: Node_Id
:= Empty
;
4950 Do_Access
: Boolean := False;
4951 Wnode
: Node_Id
:= Warn_Node
;
4952 Ret_Result
: Check_Result
:= (Empty
, Empty
);
4953 Num_Checks
: Natural := 0;
4955 procedure Add_Check
(N
: Node_Id
);
4956 -- Adds the action given to Ret_Result if N is non-Empty
4958 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
;
4959 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
4960 -- Comments required ???
4962 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean;
4963 -- True for equal literals and for nodes that denote the same constant
4964 -- entity, even if its value is not a static constant. This includes the
4965 -- case of a discriminal reference within an init proc. Removes some
4966 -- obviously superfluous checks.
4968 function Length_E_Cond
4969 (Exptyp
: Entity_Id
;
4971 Indx
: Nat
) return Node_Id
;
4972 -- Returns expression to compute:
4973 -- Typ'Length /= Exptyp'Length
4975 function Length_N_Cond
4978 Indx
: Nat
) return Node_Id
;
4979 -- Returns expression to compute:
4980 -- Typ'Length /= Expr'Length
4986 procedure Add_Check
(N
: Node_Id
) is
4990 -- For now, ignore attempt to place more than 2 checks ???
4992 if Num_Checks
= 2 then
4996 pragma Assert
(Num_Checks
<= 1);
4997 Num_Checks
:= Num_Checks
+ 1;
4998 Ret_Result
(Num_Checks
) := N
;
5006 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
is
5007 Pt
: constant Entity_Id
:= Scope
(Scope
(E
));
5009 E1
: Entity_Id
:= E
;
5012 if Ekind
(Scope
(E
)) = E_Record_Type
5013 and then Has_Discriminants
(Scope
(E
))
5015 N
:= Build_Discriminal_Subtype_Of_Component
(E
);
5018 Insert_Action
(Ck_Node
, N
);
5019 E1
:= Defining_Identifier
(N
);
5023 if Ekind
(E1
) = E_String_Literal_Subtype
then
5025 Make_Integer_Literal
(Loc
,
5026 Intval
=> String_Literal_Length
(E1
));
5028 elsif Ekind
(Pt
) = E_Protected_Type
5029 and then Has_Discriminants
(Pt
)
5030 and then Has_Completion
(Pt
)
5031 and then not Inside_Init_Proc
5034 -- If the type whose length is needed is a private component
5035 -- constrained by a discriminant, we must expand the 'Length
5036 -- attribute into an explicit computation, using the discriminal
5037 -- of the current protected operation. This is because the actual
5038 -- type of the prival is constructed after the protected opera-
5039 -- tion has been fully expanded.
5042 Indx_Type
: Node_Id
;
5045 Do_Expand
: Boolean := False;
5048 Indx_Type
:= First_Index
(E
);
5050 for J
in 1 .. Indx
- 1 loop
5051 Next_Index
(Indx_Type
);
5054 Get_Index_Bounds
(Indx_Type
, Lo
, Hi
);
5056 if Nkind
(Lo
) = N_Identifier
5057 and then Ekind
(Entity
(Lo
)) = E_In_Parameter
5059 Lo
:= Get_Discriminal
(E
, Lo
);
5063 if Nkind
(Hi
) = N_Identifier
5064 and then Ekind
(Entity
(Hi
)) = E_In_Parameter
5066 Hi
:= Get_Discriminal
(E
, Hi
);
5071 if not Is_Entity_Name
(Lo
) then
5072 Lo
:= Duplicate_Subexpr_No_Checks
(Lo
);
5075 if not Is_Entity_Name
(Hi
) then
5076 Lo
:= Duplicate_Subexpr_No_Checks
(Hi
);
5082 Make_Op_Subtract
(Loc
,
5086 Right_Opnd
=> Make_Integer_Literal
(Loc
, 1));
5091 Make_Attribute_Reference
(Loc
,
5092 Attribute_Name
=> Name_Length
,
5094 New_Occurrence_Of
(E1
, Loc
));
5097 Set_Expressions
(N
, New_List
(
5098 Make_Integer_Literal
(Loc
, Indx
)));
5107 Make_Attribute_Reference
(Loc
,
5108 Attribute_Name
=> Name_Length
,
5110 New_Occurrence_Of
(E1
, Loc
));
5113 Set_Expressions
(N
, New_List
(
5114 Make_Integer_Literal
(Loc
, Indx
)));
5126 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5129 Make_Attribute_Reference
(Loc
,
5130 Attribute_Name
=> Name_Length
,
5132 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5133 Expressions
=> New_List
(
5134 Make_Integer_Literal
(Loc
, Indx
)));
5142 function Length_E_Cond
5143 (Exptyp
: Entity_Id
;
5145 Indx
: Nat
) return Node_Id
5150 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
5151 Right_Opnd
=> Get_E_Length
(Exptyp
, Indx
));
5159 function Length_N_Cond
5162 Indx
: Nat
) return Node_Id
5167 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
5168 Right_Opnd
=> Get_N_Length
(Expr
, Indx
));
5172 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean is
5175 (Nkind
(L
) = N_Integer_Literal
5176 and then Nkind
(R
) = N_Integer_Literal
5177 and then Intval
(L
) = Intval
(R
))
5181 and then Ekind
(Entity
(L
)) = E_Constant
5182 and then ((Is_Entity_Name
(R
)
5183 and then Entity
(L
) = Entity
(R
))
5185 (Nkind
(R
) = N_Type_Conversion
5186 and then Is_Entity_Name
(Expression
(R
))
5187 and then Entity
(L
) = Entity
(Expression
(R
)))))
5191 and then Ekind
(Entity
(R
)) = E_Constant
5192 and then Nkind
(L
) = N_Type_Conversion
5193 and then Is_Entity_Name
(Expression
(L
))
5194 and then Entity
(R
) = Entity
(Expression
(L
)))
5198 and then Is_Entity_Name
(R
)
5199 and then Entity
(L
) = Entity
(R
)
5200 and then Ekind
(Entity
(L
)) = E_In_Parameter
5201 and then Inside_Init_Proc
);
5204 -- Start of processing for Selected_Length_Checks
5207 if not Expander_Active
then
5211 if Target_Typ
= Any_Type
5212 or else Target_Typ
= Any_Composite
5213 or else Raises_Constraint_Error
(Ck_Node
)
5222 T_Typ
:= Target_Typ
;
5224 if No
(Source_Typ
) then
5225 S_Typ
:= Etype
(Ck_Node
);
5227 S_Typ
:= Source_Typ
;
5230 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
5234 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
5235 S_Typ
:= Designated_Type
(S_Typ
);
5236 T_Typ
:= Designated_Type
(T_Typ
);
5239 -- A simple optimization
5241 if Nkind
(Ck_Node
) = N_Null
then
5246 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
5247 if Is_Constrained
(T_Typ
) then
5249 -- The checking code to be generated will freeze the
5250 -- corresponding array type. However, we must freeze the
5251 -- type now, so that the freeze node does not appear within
5252 -- the generated condional expression, but ahead of it.
5254 Freeze_Before
(Ck_Node
, T_Typ
);
5256 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
5257 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
5259 if Is_Access_Type
(Exptyp
) then
5260 Exptyp
:= Designated_Type
(Exptyp
);
5263 -- String_Literal case. This needs to be handled specially be-
5264 -- cause no index types are available for string literals. The
5265 -- condition is simply:
5267 -- T_Typ'Length = string-literal-length
5269 if Nkind
(Expr_Actual
) = N_String_Literal
5270 and then Ekind
(Etype
(Expr_Actual
)) = E_String_Literal_Subtype
5274 Left_Opnd
=> Get_E_Length
(T_Typ
, 1),
5276 Make_Integer_Literal
(Loc
,
5278 String_Literal_Length
(Etype
(Expr_Actual
))));
5280 -- General array case. Here we have a usable actual subtype for
5281 -- the expression, and the condition is built from the two types
5284 -- T_Typ'Length /= Exptyp'Length or else
5285 -- T_Typ'Length (2) /= Exptyp'Length (2) or else
5286 -- T_Typ'Length (3) /= Exptyp'Length (3) or else
5289 elsif Is_Constrained
(Exptyp
) then
5291 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
5305 -- At the library level, we need to ensure that the
5306 -- type of the object is elaborated before the check
5307 -- itself is emitted. This is only done if the object
5308 -- is in the current compilation unit, otherwise the
5309 -- type is frozen and elaborated in its unit.
5311 if Is_Itype
(Exptyp
)
5313 Ekind
(Cunit_Entity
(Current_Sem_Unit
)) = E_Package
5315 not In_Package_Body
(Cunit_Entity
(Current_Sem_Unit
))
5316 and then In_Open_Scopes
(Scope
(Exptyp
))
5318 Ref_Node
:= Make_Itype_Reference
(Sloc
(Ck_Node
));
5319 Set_Itype
(Ref_Node
, Exptyp
);
5320 Insert_Action
(Ck_Node
, Ref_Node
);
5323 L_Index
:= First_Index
(T_Typ
);
5324 R_Index
:= First_Index
(Exptyp
);
5326 for Indx
in 1 .. Ndims
loop
5327 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
5329 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
5331 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
5332 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
5334 -- Deal with compile time length check. Note that we
5335 -- skip this in the access case, because the access
5336 -- value may be null, so we cannot know statically.
5339 and then Compile_Time_Known_Value
(L_Low
)
5340 and then Compile_Time_Known_Value
(L_High
)
5341 and then Compile_Time_Known_Value
(R_Low
)
5342 and then Compile_Time_Known_Value
(R_High
)
5344 if Expr_Value
(L_High
) >= Expr_Value
(L_Low
) then
5345 L_Length
:= Expr_Value
(L_High
) -
5346 Expr_Value
(L_Low
) + 1;
5348 L_Length
:= UI_From_Int
(0);
5351 if Expr_Value
(R_High
) >= Expr_Value
(R_Low
) then
5352 R_Length
:= Expr_Value
(R_High
) -
5353 Expr_Value
(R_Low
) + 1;
5355 R_Length
:= UI_From_Int
(0);
5358 if L_Length
> R_Length
then
5360 (Compile_Time_Constraint_Error
5361 (Wnode
, "too few elements for}?", T_Typ
));
5363 elsif L_Length
< R_Length
then
5365 (Compile_Time_Constraint_Error
5366 (Wnode
, "too many elements for}?", T_Typ
));
5369 -- The comparison for an individual index subtype
5370 -- is omitted if the corresponding index subtypes
5371 -- statically match, since the result is known to
5372 -- be true. Note that this test is worth while even
5373 -- though we do static evaluation, because non-static
5374 -- subtypes can statically match.
5377 Subtypes_Statically_Match
5378 (Etype
(L_Index
), Etype
(R_Index
))
5381 (Same_Bounds
(L_Low
, R_Low
)
5382 and then Same_Bounds
(L_High
, R_High
))
5385 (Cond
, Length_E_Cond
(Exptyp
, T_Typ
, Indx
));
5394 -- Handle cases where we do not get a usable actual subtype that
5395 -- is constrained. This happens for example in the function call
5396 -- and explicit dereference cases. In these cases, we have to get
5397 -- the length or range from the expression itself, making sure we
5398 -- do not evaluate it more than once.
5400 -- Here Ck_Node is the original expression, or more properly the
5401 -- result of applying Duplicate_Expr to the original tree,
5402 -- forcing the result to be a name.
5406 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
5409 -- Build the condition for the explicit dereference case
5411 for Indx
in 1 .. Ndims
loop
5413 (Cond
, Length_N_Cond
(Ck_Node
, T_Typ
, Indx
));
5420 -- Construct the test and insert into the tree
5422 if Present
(Cond
) then
5424 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
5428 (Make_Raise_Constraint_Error
(Loc
,
5430 Reason
=> CE_Length_Check_Failed
));
5434 end Selected_Length_Checks
;
5436 ---------------------------
5437 -- Selected_Range_Checks --
5438 ---------------------------
5440 function Selected_Range_Checks
5442 Target_Typ
: Entity_Id
;
5443 Source_Typ
: Entity_Id
;
5444 Warn_Node
: Node_Id
) return Check_Result
5446 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
5449 Expr_Actual
: Node_Id
;
5451 Cond
: Node_Id
:= Empty
;
5452 Do_Access
: Boolean := False;
5453 Wnode
: Node_Id
:= Warn_Node
;
5454 Ret_Result
: Check_Result
:= (Empty
, Empty
);
5455 Num_Checks
: Integer := 0;
5457 procedure Add_Check
(N
: Node_Id
);
5458 -- Adds the action given to Ret_Result if N is non-Empty
5460 function Discrete_Range_Cond
5462 Typ
: Entity_Id
) return Node_Id
;
5463 -- Returns expression to compute:
5464 -- Low_Bound (Expr) < Typ'First
5466 -- High_Bound (Expr) > Typ'Last
5468 function Discrete_Expr_Cond
5470 Typ
: Entity_Id
) return Node_Id
;
5471 -- Returns expression to compute:
5476 function Get_E_First_Or_Last
5479 Nam
: Name_Id
) return Node_Id
;
5480 -- Returns expression to compute:
5481 -- E'First or E'Last
5483 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5484 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5485 -- Returns expression to compute:
5486 -- N'First or N'Last using Duplicate_Subexpr_No_Checks
5488 function Range_E_Cond
5489 (Exptyp
: Entity_Id
;
5493 -- Returns expression to compute:
5494 -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
5496 function Range_Equal_E_Cond
5497 (Exptyp
: Entity_Id
;
5499 Indx
: Nat
) return Node_Id
;
5500 -- Returns expression to compute:
5501 -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
5503 function Range_N_Cond
5506 Indx
: Nat
) return Node_Id
;
5507 -- Return expression to compute:
5508 -- Expr'First < Typ'First or else Expr'Last > Typ'Last
5514 procedure Add_Check
(N
: Node_Id
) is
5518 -- For now, ignore attempt to place more than 2 checks ???
5520 if Num_Checks
= 2 then
5524 pragma Assert
(Num_Checks
<= 1);
5525 Num_Checks
:= Num_Checks
+ 1;
5526 Ret_Result
(Num_Checks
) := N
;
5530 -------------------------
5531 -- Discrete_Expr_Cond --
5532 -------------------------
5534 function Discrete_Expr_Cond
5536 Typ
: Entity_Id
) return Node_Id
5544 Convert_To
(Base_Type
(Typ
),
5545 Duplicate_Subexpr_No_Checks
(Expr
)),
5547 Convert_To
(Base_Type
(Typ
),
5548 Get_E_First_Or_Last
(Typ
, 0, Name_First
))),
5553 Convert_To
(Base_Type
(Typ
),
5554 Duplicate_Subexpr_No_Checks
(Expr
)),
5558 Get_E_First_Or_Last
(Typ
, 0, Name_Last
))));
5559 end Discrete_Expr_Cond
;
5561 -------------------------
5562 -- Discrete_Range_Cond --
5563 -------------------------
5565 function Discrete_Range_Cond
5567 Typ
: Entity_Id
) return Node_Id
5569 LB
: Node_Id
:= Low_Bound
(Expr
);
5570 HB
: Node_Id
:= High_Bound
(Expr
);
5572 Left_Opnd
: Node_Id
;
5573 Right_Opnd
: Node_Id
;
5576 if Nkind
(LB
) = N_Identifier
5577 and then Ekind
(Entity
(LB
)) = E_Discriminant
then
5578 LB
:= New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
5581 if Nkind
(HB
) = N_Identifier
5582 and then Ekind
(Entity
(HB
)) = E_Discriminant
then
5583 HB
:= New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
5590 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(LB
)),
5594 (Base_Type
(Typ
), Get_E_First_Or_Last
(Typ
, 0, Name_First
)));
5596 if Base_Type
(Typ
) = Typ
then
5599 elsif Compile_Time_Known_Value
(High_Bound
(Scalar_Range
(Typ
)))
5601 Compile_Time_Known_Value
(High_Bound
(Scalar_Range
5604 if Is_Floating_Point_Type
(Typ
) then
5605 if Expr_Value_R
(High_Bound
(Scalar_Range
(Typ
))) =
5606 Expr_Value_R
(High_Bound
(Scalar_Range
(Base_Type
(Typ
))))
5612 if Expr_Value
(High_Bound
(Scalar_Range
(Typ
))) =
5613 Expr_Value
(High_Bound
(Scalar_Range
(Base_Type
(Typ
))))
5624 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(HB
)),
5629 Get_E_First_Or_Last
(Typ
, 0, Name_Last
)));
5631 return Make_Or_Else
(Loc
, Left_Opnd
, Right_Opnd
);
5632 end Discrete_Range_Cond
;
5634 -------------------------
5635 -- Get_E_First_Or_Last --
5636 -------------------------
5638 function Get_E_First_Or_Last
5641 Nam
: Name_Id
) return Node_Id
5649 if Is_Array_Type
(E
) then
5650 N
:= First_Index
(E
);
5652 for J
in 2 .. Indx
loop
5657 N
:= Scalar_Range
(E
);
5660 if Nkind
(N
) = N_Subtype_Indication
then
5661 LB
:= Low_Bound
(Range_Expression
(Constraint
(N
)));
5662 HB
:= High_Bound
(Range_Expression
(Constraint
(N
)));
5664 elsif Is_Entity_Name
(N
) then
5665 LB
:= Type_Low_Bound
(Etype
(N
));
5666 HB
:= Type_High_Bound
(Etype
(N
));
5669 LB
:= Low_Bound
(N
);
5670 HB
:= High_Bound
(N
);
5673 if Nam
= Name_First
then
5679 if Nkind
(Bound
) = N_Identifier
5680 and then Ekind
(Entity
(Bound
)) = E_Discriminant
5682 -- If this is a task discriminant, and we are the body, we must
5683 -- retrieve the corresponding body discriminal. This is another
5684 -- consequence of the early creation of discriminals, and the
5685 -- need to generate constraint checks before their declarations
5686 -- are made visible.
5688 if Is_Concurrent_Record_Type
(Scope
(Entity
(Bound
))) then
5690 Tsk
: constant Entity_Id
:=
5691 Corresponding_Concurrent_Type
5692 (Scope
(Entity
(Bound
)));
5696 if In_Open_Scopes
(Tsk
)
5697 and then Has_Completion
(Tsk
)
5699 -- Find discriminant of original task, and use its
5700 -- current discriminal, which is the renaming within
5703 Disc
:= First_Discriminant
(Tsk
);
5704 while Present
(Disc
) loop
5705 if Chars
(Disc
) = Chars
(Entity
(Bound
)) then
5706 Set_Scope
(Discriminal
(Disc
), Tsk
);
5707 return New_Occurrence_Of
(Discriminal
(Disc
), Loc
);
5710 Next_Discriminant
(Disc
);
5713 -- That loop should always succeed in finding a matching
5714 -- entry and returning. Fatal error if not.
5716 raise Program_Error
;
5720 New_Occurrence_Of
(Discriminal
(Entity
(Bound
)), Loc
);
5724 return New_Occurrence_Of
(Discriminal
(Entity
(Bound
)), Loc
);
5727 elsif Nkind
(Bound
) = N_Identifier
5728 and then Ekind
(Entity
(Bound
)) = E_In_Parameter
5729 and then not Inside_Init_Proc
5731 return Get_Discriminal
(E
, Bound
);
5733 elsif Nkind
(Bound
) = N_Integer_Literal
then
5734 return Make_Integer_Literal
(Loc
, Intval
(Bound
));
5737 return Duplicate_Subexpr_No_Checks
(Bound
);
5739 end Get_E_First_Or_Last
;
5745 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5748 Make_Attribute_Reference
(Loc
,
5749 Attribute_Name
=> Name_First
,
5751 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5752 Expressions
=> New_List
(
5753 Make_Integer_Literal
(Loc
, Indx
)));
5760 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5763 Make_Attribute_Reference
(Loc
,
5764 Attribute_Name
=> Name_Last
,
5766 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5767 Expressions
=> New_List
(
5768 Make_Integer_Literal
(Loc
, Indx
)));
5775 function Range_E_Cond
5776 (Exptyp
: Entity_Id
;
5778 Indx
: Nat
) return Node_Id
5785 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_First
),
5786 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5790 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_Last
),
5791 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5795 ------------------------
5796 -- Range_Equal_E_Cond --
5797 ------------------------
5799 function Range_Equal_E_Cond
5800 (Exptyp
: Entity_Id
;
5802 Indx
: Nat
) return Node_Id
5809 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_First
),
5810 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5813 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_Last
),
5814 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5815 end Range_Equal_E_Cond
;
5821 function Range_N_Cond
5824 Indx
: Nat
) return Node_Id
5831 Left_Opnd
=> Get_N_First
(Expr
, Indx
),
5832 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5836 Left_Opnd
=> Get_N_Last
(Expr
, Indx
),
5837 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5840 -- Start of processing for Selected_Range_Checks
5843 if not Expander_Active
then
5847 if Target_Typ
= Any_Type
5848 or else Target_Typ
= Any_Composite
5849 or else Raises_Constraint_Error
(Ck_Node
)
5858 T_Typ
:= Target_Typ
;
5860 if No
(Source_Typ
) then
5861 S_Typ
:= Etype
(Ck_Node
);
5863 S_Typ
:= Source_Typ
;
5866 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
5870 -- The order of evaluating T_Typ before S_Typ seems to be critical
5871 -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
5872 -- in, and since Node can be an N_Range node, it might be invalid.
5873 -- Should there be an assert check somewhere for taking the Etype of
5874 -- an N_Range node ???
5876 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
5877 S_Typ
:= Designated_Type
(S_Typ
);
5878 T_Typ
:= Designated_Type
(T_Typ
);
5881 -- A simple optimization
5883 if Nkind
(Ck_Node
) = N_Null
then
5888 -- For an N_Range Node, check for a null range and then if not
5889 -- null generate a range check action.
5891 if Nkind
(Ck_Node
) = N_Range
then
5893 -- There's no point in checking a range against itself
5895 if Ck_Node
= Scalar_Range
(T_Typ
) then
5900 T_LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
5901 T_HB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
5902 LB
: constant Node_Id
:= Low_Bound
(Ck_Node
);
5903 HB
: constant Node_Id
:= High_Bound
(Ck_Node
);
5904 Null_Range
: Boolean;
5906 Out_Of_Range_L
: Boolean;
5907 Out_Of_Range_H
: Boolean;
5910 -- Check for case where everything is static and we can
5911 -- do the check at compile time. This is skipped if we
5912 -- have an access type, since the access value may be null.
5914 -- ??? This code can be improved since you only need to know
5915 -- that the two respective bounds (LB & T_LB or HB & T_HB)
5916 -- are known at compile time to emit pertinent messages.
5918 if Compile_Time_Known_Value
(LB
)
5919 and then Compile_Time_Known_Value
(HB
)
5920 and then Compile_Time_Known_Value
(T_LB
)
5921 and then Compile_Time_Known_Value
(T_HB
)
5922 and then not Do_Access
5924 -- Floating-point case
5926 if Is_Floating_Point_Type
(S_Typ
) then
5927 Null_Range
:= Expr_Value_R
(HB
) < Expr_Value_R
(LB
);
5929 (Expr_Value_R
(LB
) < Expr_Value_R
(T_LB
))
5931 (Expr_Value_R
(LB
) > Expr_Value_R
(T_HB
));
5934 (Expr_Value_R
(HB
) > Expr_Value_R
(T_HB
))
5936 (Expr_Value_R
(HB
) < Expr_Value_R
(T_LB
));
5938 -- Fixed or discrete type case
5941 Null_Range
:= Expr_Value
(HB
) < Expr_Value
(LB
);
5943 (Expr_Value
(LB
) < Expr_Value
(T_LB
))
5945 (Expr_Value
(LB
) > Expr_Value
(T_HB
));
5948 (Expr_Value
(HB
) > Expr_Value
(T_HB
))
5950 (Expr_Value
(HB
) < Expr_Value
(T_LB
));
5953 if not Null_Range
then
5954 if Out_Of_Range_L
then
5955 if No
(Warn_Node
) then
5957 (Compile_Time_Constraint_Error
5958 (Low_Bound
(Ck_Node
),
5959 "static value out of range of}?", T_Typ
));
5963 (Compile_Time_Constraint_Error
5965 "static range out of bounds of}?", T_Typ
));
5969 if Out_Of_Range_H
then
5970 if No
(Warn_Node
) then
5972 (Compile_Time_Constraint_Error
5973 (High_Bound
(Ck_Node
),
5974 "static value out of range of}?", T_Typ
));
5978 (Compile_Time_Constraint_Error
5980 "static range out of bounds of}?", T_Typ
));
5988 LB
: Node_Id
:= Low_Bound
(Ck_Node
);
5989 HB
: Node_Id
:= High_Bound
(Ck_Node
);
5993 -- If either bound is a discriminant and we are within
5994 -- the record declaration, it is a use of the discriminant
5995 -- in a constraint of a component, and nothing can be
5996 -- checked here. The check will be emitted within the
5997 -- init proc. Before then, the discriminal has no real
6000 if Nkind
(LB
) = N_Identifier
6001 and then Ekind
(Entity
(LB
)) = E_Discriminant
6003 if Current_Scope
= Scope
(Entity
(LB
)) then
6007 New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
6011 if Nkind
(HB
) = N_Identifier
6012 and then Ekind
(Entity
(HB
)) = E_Discriminant
6014 if Current_Scope
= Scope
(Entity
(HB
)) then
6018 New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
6022 Cond
:= Discrete_Range_Cond
(Ck_Node
, T_Typ
);
6023 Set_Paren_Count
(Cond
, 1);
6029 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(HB
),
6030 Right_Opnd
=> Duplicate_Subexpr_No_Checks
(LB
)),
6031 Right_Opnd
=> Cond
);
6037 elsif Is_Scalar_Type
(S_Typ
) then
6039 -- This somewhat duplicates what Apply_Scalar_Range_Check does,
6040 -- except the above simply sets a flag in the node and lets
6041 -- gigi generate the check base on the Etype of the expression.
6042 -- Sometimes, however we want to do a dynamic check against an
6043 -- arbitrary target type, so we do that here.
6045 if Ekind
(Base_Type
(S_Typ
)) /= Ekind
(Base_Type
(T_Typ
)) then
6046 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6048 -- For literals, we can tell if the constraint error will be
6049 -- raised at compile time, so we never need a dynamic check, but
6050 -- if the exception will be raised, then post the usual warning,
6051 -- and replace the literal with a raise constraint error
6052 -- expression. As usual, skip this for access types
6054 elsif Compile_Time_Known_Value
(Ck_Node
)
6055 and then not Do_Access
6058 LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
6059 UB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
6061 Out_Of_Range
: Boolean;
6062 Static_Bounds
: constant Boolean :=
6063 Compile_Time_Known_Value
(LB
)
6064 and Compile_Time_Known_Value
(UB
);
6067 -- Following range tests should use Sem_Eval routine ???
6069 if Static_Bounds
then
6070 if Is_Floating_Point_Type
(S_Typ
) then
6072 (Expr_Value_R
(Ck_Node
) < Expr_Value_R
(LB
))
6074 (Expr_Value_R
(Ck_Node
) > Expr_Value_R
(UB
));
6076 else -- fixed or discrete type
6078 Expr_Value
(Ck_Node
) < Expr_Value
(LB
)
6080 Expr_Value
(Ck_Node
) > Expr_Value
(UB
);
6083 -- Bounds of the type are static and the literal is
6084 -- out of range so make a warning message.
6086 if Out_Of_Range
then
6087 if No
(Warn_Node
) then
6089 (Compile_Time_Constraint_Error
6091 "static value out of range of}?", T_Typ
));
6095 (Compile_Time_Constraint_Error
6097 "static value out of range of}?", T_Typ
));
6102 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6106 -- Here for the case of a non-static expression, we need a runtime
6107 -- check unless the source type range is guaranteed to be in the
6108 -- range of the target type.
6111 if not In_Subrange_Of
(S_Typ
, T_Typ
) then
6112 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6117 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
6118 if Is_Constrained
(T_Typ
) then
6120 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
6121 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
6123 if Is_Access_Type
(Exptyp
) then
6124 Exptyp
:= Designated_Type
(Exptyp
);
6127 -- String_Literal case. This needs to be handled specially be-
6128 -- cause no index types are available for string literals. The
6129 -- condition is simply:
6131 -- T_Typ'Length = string-literal-length
6133 if Nkind
(Expr_Actual
) = N_String_Literal
then
6136 -- General array case. Here we have a usable actual subtype for
6137 -- the expression, and the condition is built from the two types
6139 -- T_Typ'First < Exptyp'First or else
6140 -- T_Typ'Last > Exptyp'Last or else
6141 -- T_Typ'First(1) < Exptyp'First(1) or else
6142 -- T_Typ'Last(1) > Exptyp'Last(1) or else
6145 elsif Is_Constrained
(Exptyp
) then
6147 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
6157 L_Index
:= First_Index
(T_Typ
);
6158 R_Index
:= First_Index
(Exptyp
);
6160 for Indx
in 1 .. Ndims
loop
6161 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
6163 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
6165 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
6166 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
6168 -- Deal with compile time length check. Note that we
6169 -- skip this in the access case, because the access
6170 -- value may be null, so we cannot know statically.
6173 Subtypes_Statically_Match
6174 (Etype
(L_Index
), Etype
(R_Index
))
6176 -- If the target type is constrained then we
6177 -- have to check for exact equality of bounds
6178 -- (required for qualified expressions).
6180 if Is_Constrained
(T_Typ
) then
6183 Range_Equal_E_Cond
(Exptyp
, T_Typ
, Indx
));
6187 (Cond
, Range_E_Cond
(Exptyp
, T_Typ
, Indx
));
6198 -- Handle cases where we do not get a usable actual subtype that
6199 -- is constrained. This happens for example in the function call
6200 -- and explicit dereference cases. In these cases, we have to get
6201 -- the length or range from the expression itself, making sure we
6202 -- do not evaluate it more than once.
6204 -- Here Ck_Node is the original expression, or more properly the
6205 -- result of applying Duplicate_Expr to the original tree,
6206 -- forcing the result to be a name.
6210 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
6213 -- Build the condition for the explicit dereference case
6215 for Indx
in 1 .. Ndims
loop
6217 (Cond
, Range_N_Cond
(Ck_Node
, T_Typ
, Indx
));
6224 -- Generate an Action to check that the bounds of the
6225 -- source value are within the constraints imposed by the
6226 -- target type for a conversion to an unconstrained type.
6229 if Nkind
(Parent
(Ck_Node
)) = N_Type_Conversion
then
6231 Opnd_Index
: Node_Id
;
6232 Targ_Index
: Node_Id
;
6236 := First_Index
(Get_Actual_Subtype
(Ck_Node
));
6237 Targ_Index
:= First_Index
(T_Typ
);
6239 while Opnd_Index
/= Empty
loop
6240 if Nkind
(Opnd_Index
) = N_Range
then
6242 (Low_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6245 (High_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6249 -- If null range, no check needed.
6251 Compile_Time_Known_Value
(High_Bound
(Opnd_Index
))
6253 Compile_Time_Known_Value
(Low_Bound
(Opnd_Index
))
6255 Expr_Value
(High_Bound
(Opnd_Index
)) <
6256 Expr_Value
(Low_Bound
(Opnd_Index
))
6260 elsif Is_Out_Of_Range
6261 (Low_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6264 (High_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6267 (Compile_Time_Constraint_Error
6268 (Wnode
, "value out of range of}?", T_Typ
));
6274 (Opnd_Index
, Etype
(Targ_Index
)));
6278 Next_Index
(Opnd_Index
);
6279 Next_Index
(Targ_Index
);
6286 -- Construct the test and insert into the tree
6288 if Present
(Cond
) then
6290 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
6294 (Make_Raise_Constraint_Error
(Loc
,
6296 Reason
=> CE_Range_Check_Failed
));
6300 end Selected_Range_Checks
;
6302 -------------------------------
6303 -- Storage_Checks_Suppressed --
6304 -------------------------------
6306 function Storage_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6308 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
6309 return Is_Check_Suppressed
(E
, Storage_Check
);
6311 return Scope_Suppress
(Storage_Check
);
6313 end Storage_Checks_Suppressed
;
6315 ---------------------------
6316 -- Tag_Checks_Suppressed --
6317 ---------------------------
6319 function Tag_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6322 if Kill_Tag_Checks
(E
) then
6324 elsif Checks_May_Be_Suppressed
(E
) then
6325 return Is_Check_Suppressed
(E
, Tag_Check
);
6329 return Scope_Suppress
(Tag_Check
);
6330 end Tag_Checks_Suppressed
;