1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2005 Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 with Atree
; use Atree
;
28 with Debug
; use Debug
;
29 with Einfo
; use Einfo
;
30 with Errout
; use Errout
;
31 with Exp_Ch2
; use Exp_Ch2
;
32 with Exp_Util
; use Exp_Util
;
33 with Elists
; use Elists
;
34 with Eval_Fat
; use Eval_Fat
;
35 with Freeze
; use Freeze
;
37 with Nlists
; use Nlists
;
38 with Nmake
; use Nmake
;
40 with Output
; use Output
;
41 with Restrict
; use Restrict
;
42 with Rident
; use Rident
;
43 with Rtsfind
; use Rtsfind
;
45 with Sem_Eval
; use Sem_Eval
;
46 with Sem_Ch3
; use Sem_Ch3
;
47 with Sem_Ch8
; use Sem_Ch8
;
48 with Sem_Res
; use Sem_Res
;
49 with Sem_Util
; use Sem_Util
;
50 with Sem_Warn
; use Sem_Warn
;
51 with Sinfo
; use Sinfo
;
52 with Sinput
; use Sinput
;
53 with Snames
; use Snames
;
54 with Sprint
; use Sprint
;
55 with Stand
; use Stand
;
56 with Targparm
; use Targparm
;
57 with Tbuild
; use Tbuild
;
58 with Ttypes
; use Ttypes
;
59 with Urealp
; use Urealp
;
60 with Validsw
; use Validsw
;
62 package body Checks
is
64 -- General note: many of these routines are concerned with generating
65 -- checking code to make sure that constraint error is raised at runtime.
66 -- Clearly this code is only needed if the expander is active, since
67 -- otherwise we will not be generating code or going into the runtime
70 -- We therefore disconnect most of these checks if the expander is
71 -- inactive. This has the additional benefit that we do not need to
72 -- worry about the tree being messed up by previous errors (since errors
73 -- turn off expansion anyway).
75 -- There are a few exceptions to the above rule. For instance routines
76 -- such as Apply_Scalar_Range_Check that do not insert any code can be
77 -- safely called even when the Expander is inactive (but Errors_Detected
78 -- is 0). The benefit of executing this code when expansion is off, is
79 -- the ability to emit constraint error warning for static expressions
80 -- even when we are not generating code.
82 -------------------------------------
83 -- Suppression of Redundant Checks --
84 -------------------------------------
86 -- This unit implements a limited circuit for removal of redundant
87 -- checks. The processing is based on a tracing of simple sequential
88 -- flow. For any sequence of statements, we save expressions that are
89 -- marked to be checked, and then if the same expression appears later
90 -- with the same check, then under certain circumstances, the second
91 -- check can be suppressed.
93 -- Basically, we can suppress the check if we know for certain that
94 -- the previous expression has been elaborated (together with its
95 -- check), and we know that the exception frame is the same, and that
96 -- nothing has happened to change the result of the exception.
98 -- Let us examine each of these three conditions in turn to describe
99 -- how we ensure that this condition is met.
101 -- First, we need to know for certain that the previous expression has
102 -- been executed. This is done principly by the mechanism of calling
103 -- Conditional_Statements_Begin at the start of any statement sequence
104 -- and Conditional_Statements_End at the end. The End call causes all
105 -- checks remembered since the Begin call to be discarded. This does
106 -- miss a few cases, notably the case of a nested BEGIN-END block with
107 -- no exception handlers. But the important thing is to be conservative.
108 -- The other protection is that all checks are discarded if a label
109 -- is encountered, since then the assumption of sequential execution
110 -- is violated, and we don't know enough about the flow.
112 -- Second, we need to know that the exception frame is the same. We
113 -- do this by killing all remembered checks when we enter a new frame.
114 -- Again, that's over-conservative, but generally the cases we can help
115 -- with are pretty local anyway (like the body of a loop for example).
117 -- Third, we must be sure to forget any checks which are no longer valid.
118 -- This is done by two mechanisms, first the Kill_Checks_Variable call is
119 -- used to note any changes to local variables. We only attempt to deal
120 -- with checks involving local variables, so we do not need to worry
121 -- about global variables. Second, a call to any non-global procedure
122 -- causes us to abandon all stored checks, since such a all may affect
123 -- the values of any local variables.
125 -- The following define the data structures used to deal with remembering
126 -- checks so that redundant checks can be eliminated as described above.
128 -- Right now, the only expressions that we deal with are of the form of
129 -- simple local objects (either declared locally, or IN parameters) or
130 -- such objects plus/minus a compile time known constant. We can do
131 -- more later on if it seems worthwhile, but this catches many simple
132 -- cases in practice.
134 -- The following record type reflects a single saved check. An entry
135 -- is made in the stack of saved checks if and only if the expression
136 -- has been elaborated with the indicated checks.
138 type Saved_Check
is record
140 -- Set True if entry is killed by Kill_Checks
143 -- The entity involved in the expression that is checked
146 -- A compile time value indicating the result of adding or
147 -- subtracting a compile time value. This value is to be
148 -- added to the value of the Entity. A value of zero is
149 -- used for the case of a simple entity reference.
151 Check_Type
: Character;
152 -- This is set to 'R' for a range check (in which case Target_Type
153 -- is set to the target type for the range check) or to 'O' for an
154 -- overflow check (in which case Target_Type is set to Empty).
156 Target_Type
: Entity_Id
;
157 -- Used only if Do_Range_Check is set. Records the target type for
158 -- the check. We need this, because a check is a duplicate only if
159 -- it has a the same target type (or more accurately one with a
160 -- range that is smaller or equal to the stored target type of a
164 -- The following table keeps track of saved checks. Rather than use an
165 -- extensible table. We just use a table of fixed size, and we discard
166 -- any saved checks that do not fit. That's very unlikely to happen and
167 -- this is only an optimization in any case.
169 Saved_Checks
: array (Int
range 1 .. 200) of Saved_Check
;
170 -- Array of saved checks
172 Num_Saved_Checks
: Nat
:= 0;
173 -- Number of saved checks
175 -- The following stack keeps track of statement ranges. It is treated
176 -- as a stack. When Conditional_Statements_Begin is called, an entry
177 -- is pushed onto this stack containing the value of Num_Saved_Checks
178 -- at the time of the call. Then when Conditional_Statements_End is
179 -- called, this value is popped off and used to reset Num_Saved_Checks.
181 -- Note: again, this is a fixed length stack with a size that should
182 -- always be fine. If the value of the stack pointer goes above the
183 -- limit, then we just forget all saved checks.
185 Saved_Checks_Stack
: array (Int
range 1 .. 100) of Nat
;
186 Saved_Checks_TOS
: Nat
:= 0;
188 -----------------------
189 -- Local Subprograms --
190 -----------------------
192 procedure Apply_Float_Conversion_Check
194 Target_Typ
: Entity_Id
);
195 -- The checks on a conversion from a floating-point type to an integer
196 -- type are delicate. They have to be performed before conversion, they
197 -- have to raise an exception when the operand is a NaN, and rounding must
198 -- be taken into account to determine the safe bounds of the operand.
200 procedure Apply_Selected_Length_Checks
202 Target_Typ
: Entity_Id
;
203 Source_Typ
: Entity_Id
;
204 Do_Static
: Boolean);
205 -- This is the subprogram that does all the work for Apply_Length_Check
206 -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as
207 -- described for the above routines. The Do_Static flag indicates that
208 -- only a static check is to be done.
210 procedure Apply_Selected_Range_Checks
212 Target_Typ
: Entity_Id
;
213 Source_Typ
: Entity_Id
;
214 Do_Static
: Boolean);
215 -- This is the subprogram that does all the work for Apply_Range_Check.
216 -- Expr, Target_Typ and Source_Typ are as described for the above
217 -- routine. The Do_Static flag indicates that only a static check is
222 Check_Type
: Character;
223 Target_Type
: Entity_Id
;
224 Entry_OK
: out Boolean;
228 -- This routine is used by Enable_Range_Check and Enable_Overflow_Check
229 -- to see if a check is of the form for optimization, and if so, to see
230 -- if it has already been performed. Expr is the expression to check,
231 -- and Check_Type is 'R' for a range check, 'O' for an overflow check.
232 -- Target_Type is the target type for a range check, and Empty for an
233 -- overflow check. If the entry is not of the form for optimization,
234 -- then Entry_OK is set to False, and the remaining out parameters
235 -- are undefined. If the entry is OK, then Ent/Ofs are set to the
236 -- entity and offset from the expression. Check_Num is the number of
237 -- a matching saved entry in Saved_Checks, or zero if no such entry
240 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
;
241 -- If a discriminal is used in constraining a prival, Return reference
242 -- to the discriminal of the protected body (which renames the parameter
243 -- of the enclosing protected operation). This clumsy transformation is
244 -- needed because privals are created too late and their actual subtypes
245 -- are not available when analysing the bodies of the protected operations.
246 -- To be cleaned up???
248 function Guard_Access
251 Ck_Node
: Node_Id
) return Node_Id
;
252 -- In the access type case, guard the test with a test to ensure
253 -- that the access value is non-null, since the checks do not
254 -- not apply to null access values.
256 procedure Install_Null_Excluding_Check
(N
: Node_Id
);
257 -- Determines whether an access node requires a runtime access check and
258 -- if so inserts the appropriate run-time check
260 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
);
261 -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the
262 -- Constraint_Error node.
264 function Selected_Length_Checks
266 Target_Typ
: Entity_Id
;
267 Source_Typ
: Entity_Id
;
268 Warn_Node
: Node_Id
) return Check_Result
;
269 -- Like Apply_Selected_Length_Checks, except it doesn't modify
270 -- anything, just returns a list of nodes as described in the spec of
271 -- this package for the Range_Check function.
273 function Selected_Range_Checks
275 Target_Typ
: Entity_Id
;
276 Source_Typ
: Entity_Id
;
277 Warn_Node
: Node_Id
) return Check_Result
;
278 -- Like Apply_Selected_Range_Checks, except it doesn't modify anything,
279 -- just returns a list of nodes as described in the spec of this package
280 -- for the Range_Check function.
282 ------------------------------
283 -- Access_Checks_Suppressed --
284 ------------------------------
286 function Access_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
288 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
289 return Is_Check_Suppressed
(E
, Access_Check
);
291 return Scope_Suppress
(Access_Check
);
293 end Access_Checks_Suppressed
;
295 -------------------------------------
296 -- Accessibility_Checks_Suppressed --
297 -------------------------------------
299 function Accessibility_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
301 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
302 return Is_Check_Suppressed
(E
, Accessibility_Check
);
304 return Scope_Suppress
(Accessibility_Check
);
306 end Accessibility_Checks_Suppressed
;
308 -------------------------
309 -- Append_Range_Checks --
310 -------------------------
312 procedure Append_Range_Checks
313 (Checks
: Check_Result
;
315 Suppress_Typ
: Entity_Id
;
316 Static_Sloc
: Source_Ptr
;
319 Internal_Flag_Node
: constant Node_Id
:= Flag_Node
;
320 Internal_Static_Sloc
: constant Source_Ptr
:= Static_Sloc
;
322 Checks_On
: constant Boolean :=
323 (not Index_Checks_Suppressed
(Suppress_Typ
))
325 (not Range_Checks_Suppressed
(Suppress_Typ
));
328 -- For now we just return if Checks_On is false, however this should
329 -- be enhanced to check for an always True value in the condition
330 -- and to generate a compilation warning???
332 if not Checks_On
then
337 exit when No
(Checks
(J
));
339 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
340 and then Present
(Condition
(Checks
(J
)))
342 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
343 Append_To
(Stmts
, Checks
(J
));
344 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
350 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
351 Reason
=> CE_Range_Check_Failed
));
354 end Append_Range_Checks
;
356 ------------------------
357 -- Apply_Access_Check --
358 ------------------------
360 procedure Apply_Access_Check
(N
: Node_Id
) is
361 P
: constant Node_Id
:= Prefix
(N
);
364 if Inside_A_Generic
then
368 if Is_Entity_Name
(P
) then
369 Check_Unset_Reference
(P
);
372 -- We do not need access checks if prefix is known to be non-null
374 if Known_Non_Null
(P
) then
377 -- We do not need access checks if they are suppressed on the type
379 elsif Access_Checks_Suppressed
(Etype
(P
)) then
382 -- We do not need checks if we are not generating code (i.e. the
383 -- expander is not active). This is not just an optimization, there
384 -- are cases (e.g. with pragma Debug) where generating the checks
385 -- can cause real trouble).
387 elsif not Expander_Active
then
391 -- Case where P is an entity name
393 if Is_Entity_Name
(P
) then
395 Ent
: constant Entity_Id
:= Entity
(P
);
398 if Access_Checks_Suppressed
(Ent
) then
402 -- Otherwise we are going to generate an access check, and
403 -- are we have done it, the entity will now be known non null
404 -- But we have to check for safe sequential semantics here!
406 if Safe_To_Capture_Value
(N
, Ent
) then
407 Set_Is_Known_Non_Null
(Ent
);
412 -- Access check is required
414 Install_Null_Excluding_Check
(P
);
415 end Apply_Access_Check
;
417 -------------------------------
418 -- Apply_Accessibility_Check --
419 -------------------------------
421 procedure Apply_Accessibility_Check
(N
: Node_Id
; Typ
: Entity_Id
) is
422 Loc
: constant Source_Ptr
:= Sloc
(N
);
423 Param_Ent
: constant Entity_Id
:= Param_Entity
(N
);
424 Param_Level
: Node_Id
;
425 Type_Level
: Node_Id
;
428 if Inside_A_Generic
then
431 -- Only apply the run-time check if the access parameter
432 -- has an associated extra access level parameter and
433 -- when the level of the type is less deep than the level
434 -- of the access parameter.
436 elsif Present
(Param_Ent
)
437 and then Present
(Extra_Accessibility
(Param_Ent
))
438 and then UI_Gt
(Object_Access_Level
(N
),
439 Type_Access_Level
(Typ
))
440 and then not Accessibility_Checks_Suppressed
(Param_Ent
)
441 and then not Accessibility_Checks_Suppressed
(Typ
)
444 New_Occurrence_Of
(Extra_Accessibility
(Param_Ent
), Loc
);
447 Make_Integer_Literal
(Loc
, Type_Access_Level
(Typ
));
449 -- Raise Program_Error if the accessibility level of the
450 -- the access parameter is deeper than the level of the
451 -- target access type.
454 Make_Raise_Program_Error
(Loc
,
457 Left_Opnd
=> Param_Level
,
458 Right_Opnd
=> Type_Level
),
459 Reason
=> PE_Accessibility_Check_Failed
));
461 Analyze_And_Resolve
(N
);
463 end Apply_Accessibility_Check
;
465 ---------------------------
466 -- Apply_Alignment_Check --
467 ---------------------------
469 procedure Apply_Alignment_Check
(E
: Entity_Id
; N
: Node_Id
) is
470 AC
: constant Node_Id
:= Address_Clause
(E
);
471 Typ
: constant Entity_Id
:= Etype
(E
);
475 Alignment_Required
: constant Boolean := Maximum_Alignment
> 1;
476 -- Constant to show whether target requires alignment checks
479 -- See if check needed. Note that we never need a check if the
480 -- maximum alignment is one, since the check will always succeed
483 or else not Check_Address_Alignment
(AC
)
484 or else not Alignment_Required
490 Expr
:= Expression
(AC
);
492 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
then
493 Expr
:= Expression
(Expr
);
495 elsif Nkind
(Expr
) = N_Function_Call
496 and then Is_Entity_Name
(Name
(Expr
))
497 and then Is_RTE
(Entity
(Name
(Expr
)), RE_To_Address
)
499 Expr
:= First
(Parameter_Associations
(Expr
));
501 if Nkind
(Expr
) = N_Parameter_Association
then
502 Expr
:= Explicit_Actual_Parameter
(Expr
);
506 -- Here Expr is the address value. See if we know that the
507 -- value is unacceptable at compile time.
509 if Compile_Time_Known_Value
(Expr
)
510 and then (Known_Alignment
(E
) or else Known_Alignment
(Typ
))
513 AL
: Uint
:= Alignment
(Typ
);
516 -- The object alignment might be more restrictive than the
519 if Known_Alignment
(E
) then
523 if Expr_Value
(Expr
) mod AL
/= 0 then
525 Make_Raise_Program_Error
(Loc
,
526 Reason
=> PE_Misaligned_Address_Value
));
528 ("?specified address for& not " &
529 "consistent with alignment ('R'M 13.3(27))", Expr
, E
);
533 -- Here we do not know if the value is acceptable, generate
534 -- code to raise PE if alignment is inappropriate.
537 -- Skip generation of this code if we don't want elab code
539 if not Restriction_Active
(No_Elaboration_Code
) then
540 Insert_After_And_Analyze
(N
,
541 Make_Raise_Program_Error
(Loc
,
548 (RTE
(RE_Integer_Address
),
549 Duplicate_Subexpr_No_Checks
(Expr
)),
551 Make_Attribute_Reference
(Loc
,
552 Prefix
=> New_Occurrence_Of
(E
, Loc
),
553 Attribute_Name
=> Name_Alignment
)),
554 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
555 Reason
=> PE_Misaligned_Address_Value
),
556 Suppress
=> All_Checks
);
563 when RE_Not_Available
=>
565 end Apply_Alignment_Check
;
567 -------------------------------------
568 -- Apply_Arithmetic_Overflow_Check --
569 -------------------------------------
571 -- This routine is called only if the type is an integer type, and
572 -- a software arithmetic overflow check must be performed for op
573 -- (add, subtract, multiply). The check is performed only if
574 -- Software_Overflow_Checking is enabled and Do_Overflow_Check
575 -- is set. In this case we expand the operation into a more complex
576 -- sequence of tests that ensures that overflow is properly caught.
578 procedure Apply_Arithmetic_Overflow_Check
(N
: Node_Id
) is
579 Loc
: constant Source_Ptr
:= Sloc
(N
);
580 Typ
: constant Entity_Id
:= Etype
(N
);
581 Rtyp
: constant Entity_Id
:= Root_Type
(Typ
);
582 Siz
: constant Int
:= UI_To_Int
(Esize
(Rtyp
));
583 Dsiz
: constant Int
:= Siz
* 2;
590 -- Skip this if overflow checks are done in back end, or the overflow
591 -- flag is not set anyway, or we are not doing code expansion.
593 if Backend_Overflow_Checks_On_Target
594 or else not Do_Overflow_Check
(N
)
595 or else not Expander_Active
600 -- Otherwise, we generate the full general code for front end overflow
601 -- detection, which works by doing arithmetic in a larger type:
607 -- Typ (Checktyp (x) op Checktyp (y));
609 -- where Typ is the type of the original expression, and Checktyp is
610 -- an integer type of sufficient length to hold the largest possible
613 -- In the case where check type exceeds the size of Long_Long_Integer,
614 -- we use a different approach, expanding to:
616 -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y)))
618 -- where xxx is Add, Multiply or Subtract as appropriate
620 -- Find check type if one exists
622 if Dsiz
<= Standard_Integer_Size
then
623 Ctyp
:= Standard_Integer
;
625 elsif Dsiz
<= Standard_Long_Long_Integer_Size
then
626 Ctyp
:= Standard_Long_Long_Integer
;
628 -- No check type exists, use runtime call
631 if Nkind
(N
) = N_Op_Add
then
632 Cent
:= RE_Add_With_Ovflo_Check
;
634 elsif Nkind
(N
) = N_Op_Multiply
then
635 Cent
:= RE_Multiply_With_Ovflo_Check
;
638 pragma Assert
(Nkind
(N
) = N_Op_Subtract
);
639 Cent
:= RE_Subtract_With_Ovflo_Check
;
644 Make_Function_Call
(Loc
,
645 Name
=> New_Reference_To
(RTE
(Cent
), Loc
),
646 Parameter_Associations
=> New_List
(
647 OK_Convert_To
(RTE
(RE_Integer_64
), Left_Opnd
(N
)),
648 OK_Convert_To
(RTE
(RE_Integer_64
), Right_Opnd
(N
))))));
650 Analyze_And_Resolve
(N
, Typ
);
654 -- If we fall through, we have the case where we do the arithmetic in
655 -- the next higher type and get the check by conversion. In these cases
656 -- Ctyp is set to the type to be used as the check type.
658 Opnod
:= Relocate_Node
(N
);
660 Opnd
:= OK_Convert_To
(Ctyp
, Left_Opnd
(Opnod
));
663 Set_Etype
(Opnd
, Ctyp
);
664 Set_Analyzed
(Opnd
, True);
665 Set_Left_Opnd
(Opnod
, Opnd
);
667 Opnd
:= OK_Convert_To
(Ctyp
, Right_Opnd
(Opnod
));
670 Set_Etype
(Opnd
, Ctyp
);
671 Set_Analyzed
(Opnd
, True);
672 Set_Right_Opnd
(Opnod
, Opnd
);
674 -- The type of the operation changes to the base type of the check
675 -- type, and we reset the overflow check indication, since clearly
676 -- no overflow is possible now that we are using a double length
677 -- type. We also set the Analyzed flag to avoid a recursive attempt
678 -- to expand the node.
680 Set_Etype
(Opnod
, Base_Type
(Ctyp
));
681 Set_Do_Overflow_Check
(Opnod
, False);
682 Set_Analyzed
(Opnod
, True);
684 -- Now build the outer conversion
686 Opnd
:= OK_Convert_To
(Typ
, Opnod
);
688 Set_Etype
(Opnd
, Typ
);
690 -- In the discrete type case, we directly generate the range check
691 -- for the outer operand. This range check will implement the required
694 if Is_Discrete_Type
(Typ
) then
696 Generate_Range_Check
(Expression
(N
), Typ
, CE_Overflow_Check_Failed
);
698 -- For other types, we enable overflow checking on the conversion,
699 -- after setting the node as analyzed to prevent recursive attempts
700 -- to expand the conversion node.
703 Set_Analyzed
(Opnd
, True);
704 Enable_Overflow_Check
(Opnd
);
709 when RE_Not_Available
=>
711 end Apply_Arithmetic_Overflow_Check
;
713 ----------------------------
714 -- Apply_Array_Size_Check --
715 ----------------------------
717 -- The situation is as follows. In GNAT 3 (GCC 2.x), the size in bits
718 -- is computed in 32 bits without an overflow check. That's a real
719 -- problem for Ada. So what we do in GNAT 3 is to approximate the
720 -- size of an array by manually multiplying the element size by the
721 -- number of elements, and comparing that against the allowed limits.
723 -- In GNAT 5, the size in byte is still computed in 32 bits without
724 -- an overflow check in the dynamic case, but the size in bits is
725 -- computed in 64 bits. We assume that's good enough, and we do not
726 -- bother to generate any front end test.
728 procedure Apply_Array_Size_Check
(N
: Node_Id
; Typ
: Entity_Id
) is
729 Loc
: constant Source_Ptr
:= Sloc
(N
);
730 Ctyp
: constant Entity_Id
:= Component_Type
(Typ
);
731 Ent
: constant Entity_Id
:= Defining_Identifier
(N
);
743 Static
: Boolean := True;
744 -- Set false if any index subtye bound is non-static
746 Umark
: constant Uintp
.Save_Mark
:= Uintp
.Mark
;
747 -- We can throw away all the Uint computations here, since they are
748 -- done only to generate boolean test results.
751 -- Size to check against
753 function Is_Address_Or_Import
(Decl
: Node_Id
) return Boolean;
754 -- Determines if Decl is an address clause or Import/Interface pragma
755 -- that references the defining identifier of the current declaration.
757 --------------------------
758 -- Is_Address_Or_Import --
759 --------------------------
761 function Is_Address_Or_Import
(Decl
: Node_Id
) return Boolean is
763 if Nkind
(Decl
) = N_At_Clause
then
764 return Chars
(Identifier
(Decl
)) = Chars
(Ent
);
766 elsif Nkind
(Decl
) = N_Attribute_Definition_Clause
then
768 Chars
(Decl
) = Name_Address
770 Nkind
(Name
(Decl
)) = N_Identifier
772 Chars
(Name
(Decl
)) = Chars
(Ent
);
774 elsif Nkind
(Decl
) = N_Pragma
then
775 if (Chars
(Decl
) = Name_Import
777 Chars
(Decl
) = Name_Interface
)
778 and then Present
(Pragma_Argument_Associations
(Decl
))
781 F
: constant Node_Id
:=
782 First
(Pragma_Argument_Associations
(Decl
));
790 Nkind
(Expression
(Next
(F
))) = N_Identifier
792 Chars
(Expression
(Next
(F
))) = Chars
(Ent
);
802 end Is_Address_Or_Import
;
804 -- Start of processing for Apply_Array_Size_Check
807 -- Do size check on local arrays. We only need this in the GCC 2
808 -- case, since in GCC 3, we expect the back end to properly handle
809 -- things. This routine can be removed when we baseline GNAT 3.
811 if Opt
.GCC_Version
>= 3 then
815 -- No need for a check if not expanding
817 if not Expander_Active
then
821 -- No need for a check if checks are suppressed
823 if Storage_Checks_Suppressed
(Typ
) then
827 -- It is pointless to insert this check inside an init proc, because
828 -- that's too late, we have already built the object to be the right
829 -- size, and if it's too large, too bad!
831 if Inside_Init_Proc
then
835 -- Look head for pragma interface/import or address clause applying
836 -- to this entity. If found, we suppress the check entirely. For now
837 -- we only look ahead 20 declarations to stop this becoming too slow
838 -- Note that eventually this whole routine gets moved to gigi.
841 for Ctr
in 1 .. 20 loop
845 if Is_Address_Or_Import
(Decl
) then
850 -- First step is to calculate the maximum number of elements. For
851 -- this calculation, we use the actual size of the subtype if it is
852 -- static, and if a bound of a subtype is non-static, we go to the
853 -- bound of the base type.
856 Indx
:= First_Index
(Typ
);
857 while Present
(Indx
) loop
858 Xtyp
:= Etype
(Indx
);
859 Lo
:= Type_Low_Bound
(Xtyp
);
860 Hi
:= Type_High_Bound
(Xtyp
);
862 -- If any bound raises constraint error, we will never get this
863 -- far, so there is no need to generate any kind of check.
865 if Raises_Constraint_Error
(Lo
)
867 Raises_Constraint_Error
(Hi
)
869 Uintp
.Release
(Umark
);
873 -- Otherwise get bounds values
875 if Is_Static_Expression
(Lo
) then
876 Lob
:= Expr_Value
(Lo
);
878 Lob
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Xtyp
)));
882 if Is_Static_Expression
(Hi
) then
883 Hib
:= Expr_Value
(Hi
);
885 Hib
:= Expr_Value
(Type_High_Bound
(Base_Type
(Xtyp
)));
889 Siz
:= Siz
* UI_Max
(Hib
- Lob
+ 1, Uint_0
);
893 -- Compute the limit against which we want to check. For subprograms,
894 -- where the array will go on the stack, we use 8*2**24, which (in
895 -- bits) is the size of a 16 megabyte array.
897 if Is_Subprogram
(Scope
(Ent
)) then
898 Check_Siz
:= Uint_2
** 27;
900 Check_Siz
:= Uint_2
** 31;
903 -- If we have all static bounds and Siz is too large, then we know
904 -- we know we have a storage error right now, so generate message
906 if Static
and then Siz
>= Check_Siz
then
908 Make_Raise_Storage_Error
(Loc
,
909 Reason
=> SE_Object_Too_Large
));
910 Error_Msg_N
("?Storage_Error will be raised at run-time", N
);
911 Uintp
.Release
(Umark
);
915 -- Case of component size known at compile time. If the array
916 -- size is definitely in range, then we do not need a check.
918 if Known_Esize
(Ctyp
)
919 and then Siz
* Esize
(Ctyp
) < Check_Siz
921 Uintp
.Release
(Umark
);
925 -- Here if a dynamic check is required
927 -- What we do is to build an expression for the size of the array,
928 -- which is computed as the 'Size of the array component, times
929 -- the size of each dimension.
931 Uintp
.Release
(Umark
);
934 Make_Attribute_Reference
(Loc
,
935 Prefix
=> New_Occurrence_Of
(Ctyp
, Loc
),
936 Attribute_Name
=> Name_Size
);
938 Indx
:= First_Index
(Typ
);
939 for J
in 1 .. Number_Dimensions
(Typ
) loop
940 if Sloc
(Etype
(Indx
)) = Sloc
(N
) then
941 Ensure_Defined
(Etype
(Indx
), N
);
945 Make_Op_Multiply
(Loc
,
948 Make_Attribute_Reference
(Loc
,
949 Prefix
=> New_Occurrence_Of
(Typ
, Loc
),
950 Attribute_Name
=> Name_Length
,
951 Expressions
=> New_List
(
952 Make_Integer_Literal
(Loc
, J
))));
959 Make_Raise_Storage_Error
(Loc
,
964 Make_Integer_Literal
(Loc
,
965 Intval
=> Check_Siz
)),
966 Reason
=> SE_Object_Too_Large
);
968 Set_Size_Check_Code
(Defining_Identifier
(N
), Code
);
969 Insert_Action
(N
, Code
, Suppress
=> All_Checks
);
970 end Apply_Array_Size_Check
;
972 ----------------------------
973 -- Apply_Constraint_Check --
974 ----------------------------
976 procedure Apply_Constraint_Check
979 No_Sliding
: Boolean := False)
981 Desig_Typ
: Entity_Id
;
984 if Inside_A_Generic
then
987 elsif Is_Scalar_Type
(Typ
) then
988 Apply_Scalar_Range_Check
(N
, Typ
);
990 elsif Is_Array_Type
(Typ
) then
992 -- A useful optimization: an aggregate with only an Others clause
993 -- always has the right bounds.
995 if Nkind
(N
) = N_Aggregate
996 and then No
(Expressions
(N
))
998 (First
(Choices
(First
(Component_Associations
(N
)))))
1004 if Is_Constrained
(Typ
) then
1005 Apply_Length_Check
(N
, Typ
);
1008 Apply_Range_Check
(N
, Typ
);
1011 Apply_Range_Check
(N
, Typ
);
1014 elsif (Is_Record_Type
(Typ
)
1015 or else Is_Private_Type
(Typ
))
1016 and then Has_Discriminants
(Base_Type
(Typ
))
1017 and then Is_Constrained
(Typ
)
1019 Apply_Discriminant_Check
(N
, Typ
);
1021 elsif Is_Access_Type
(Typ
) then
1023 Desig_Typ
:= Designated_Type
(Typ
);
1025 -- No checks necessary if expression statically null
1027 if Nkind
(N
) = N_Null
then
1030 -- No sliding possible on access to arrays
1032 elsif Is_Array_Type
(Desig_Typ
) then
1033 if Is_Constrained
(Desig_Typ
) then
1034 Apply_Length_Check
(N
, Typ
);
1037 Apply_Range_Check
(N
, Typ
);
1039 elsif Has_Discriminants
(Base_Type
(Desig_Typ
))
1040 and then Is_Constrained
(Desig_Typ
)
1042 Apply_Discriminant_Check
(N
, Typ
);
1045 if Can_Never_Be_Null
(Typ
)
1046 and then not Can_Never_Be_Null
(Etype
(N
))
1048 Install_Null_Excluding_Check
(N
);
1051 end Apply_Constraint_Check
;
1053 ------------------------------
1054 -- Apply_Discriminant_Check --
1055 ------------------------------
1057 procedure Apply_Discriminant_Check
1060 Lhs
: Node_Id
:= Empty
)
1062 Loc
: constant Source_Ptr
:= Sloc
(N
);
1063 Do_Access
: constant Boolean := Is_Access_Type
(Typ
);
1064 S_Typ
: Entity_Id
:= Etype
(N
);
1068 function Is_Aliased_Unconstrained_Component
return Boolean;
1069 -- It is possible for an aliased component to have a nominal
1070 -- unconstrained subtype (through instantiation). If this is a
1071 -- discriminated component assigned in the expansion of an aggregate
1072 -- in an initialization, the check must be suppressed. This unusual
1073 -- situation requires a predicate of its own (see 7503-008).
1075 ----------------------------------------
1076 -- Is_Aliased_Unconstrained_Component --
1077 ----------------------------------------
1079 function Is_Aliased_Unconstrained_Component
return Boolean is
1084 if Nkind
(Lhs
) /= N_Selected_Component
then
1087 Comp
:= Entity
(Selector_Name
(Lhs
));
1088 Pref
:= Prefix
(Lhs
);
1091 if Ekind
(Comp
) /= E_Component
1092 or else not Is_Aliased
(Comp
)
1097 return not Comes_From_Source
(Pref
)
1098 and then In_Instance
1099 and then not Is_Constrained
(Etype
(Comp
));
1100 end Is_Aliased_Unconstrained_Component
;
1102 -- Start of processing for Apply_Discriminant_Check
1106 T_Typ
:= Designated_Type
(Typ
);
1111 -- Nothing to do if discriminant checks are suppressed or else no code
1112 -- is to be generated
1114 if not Expander_Active
1115 or else Discriminant_Checks_Suppressed
(T_Typ
)
1120 -- No discriminant checks necessary for access when expression
1121 -- is statically Null. This is not only an optimization, this is
1122 -- fundamental because otherwise discriminant checks may be generated
1123 -- in init procs for types containing an access to a non-frozen yet
1124 -- record, causing a deadly forward reference.
1126 -- Also, if the expression is of an access type whose designated
1127 -- type is incomplete, then the access value must be null and
1128 -- we suppress the check.
1130 if Nkind
(N
) = N_Null
then
1133 elsif Is_Access_Type
(S_Typ
) then
1134 S_Typ
:= Designated_Type
(S_Typ
);
1136 if Ekind
(S_Typ
) = E_Incomplete_Type
then
1141 -- If an assignment target is present, then we need to generate
1142 -- the actual subtype if the target is a parameter or aliased
1143 -- object with an unconstrained nominal subtype.
1146 and then (Present
(Param_Entity
(Lhs
))
1147 or else (not Is_Constrained
(T_Typ
)
1148 and then Is_Aliased_View
(Lhs
)
1149 and then not Is_Aliased_Unconstrained_Component
))
1151 T_Typ
:= Get_Actual_Subtype
(Lhs
);
1154 -- Nothing to do if the type is unconstrained (this is the case
1155 -- where the actual subtype in the RM sense of N is unconstrained
1156 -- and no check is required).
1158 if not Is_Constrained
(T_Typ
) then
1162 -- Nothing to do if the type is an Unchecked_Union
1164 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
1168 -- Suppress checks if the subtypes are the same.
1169 -- the check must be preserved in an assignment to a formal, because
1170 -- the constraint is given by the actual.
1172 if Nkind
(Original_Node
(N
)) /= N_Allocator
1174 or else not Is_Entity_Name
(Lhs
)
1175 or else No
(Param_Entity
(Lhs
)))
1178 or else (Do_Access
and then Designated_Type
(Typ
) = S_Typ
))
1179 and then not Is_Aliased_View
(Lhs
)
1184 -- We can also eliminate checks on allocators with a subtype mark
1185 -- that coincides with the context type. The context type may be a
1186 -- subtype without a constraint (common case, a generic actual).
1188 elsif Nkind
(Original_Node
(N
)) = N_Allocator
1189 and then Is_Entity_Name
(Expression
(Original_Node
(N
)))
1192 Alloc_Typ
: constant Entity_Id
:=
1193 Entity
(Expression
(Original_Node
(N
)));
1196 if Alloc_Typ
= T_Typ
1197 or else (Nkind
(Parent
(T_Typ
)) = N_Subtype_Declaration
1198 and then Is_Entity_Name
(
1199 Subtype_Indication
(Parent
(T_Typ
)))
1200 and then Alloc_Typ
= Base_Type
(T_Typ
))
1208 -- See if we have a case where the types are both constrained, and
1209 -- all the constraints are constants. In this case, we can do the
1210 -- check successfully at compile time.
1212 -- We skip this check for the case where the node is a rewritten`
1213 -- allocator, because it already carries the context subtype, and
1214 -- extracting the discriminants from the aggregate is messy.
1216 if Is_Constrained
(S_Typ
)
1217 and then Nkind
(Original_Node
(N
)) /= N_Allocator
1227 -- S_Typ may not have discriminants in the case where it is a
1228 -- private type completed by a default discriminated type. In
1229 -- that case, we need to get the constraints from the
1230 -- underlying_type. If the underlying type is unconstrained (i.e.
1231 -- has no default discriminants) no check is needed.
1233 if Has_Discriminants
(S_Typ
) then
1234 Discr
:= First_Discriminant
(S_Typ
);
1235 DconS
:= First_Elmt
(Discriminant_Constraint
(S_Typ
));
1238 Discr
:= First_Discriminant
(Underlying_Type
(S_Typ
));
1241 (Discriminant_Constraint
(Underlying_Type
(S_Typ
)));
1247 -- A further optimization: if T_Typ is derived from S_Typ
1248 -- without imposing a constraint, no check is needed.
1250 if Nkind
(Original_Node
(Parent
(T_Typ
))) =
1251 N_Full_Type_Declaration
1254 Type_Def
: constant Node_Id
:=
1256 (Original_Node
(Parent
(T_Typ
)));
1258 if Nkind
(Type_Def
) = N_Derived_Type_Definition
1259 and then Is_Entity_Name
(Subtype_Indication
(Type_Def
))
1260 and then Entity
(Subtype_Indication
(Type_Def
)) = S_Typ
1268 DconT
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
1270 while Present
(Discr
) loop
1271 ItemS
:= Node
(DconS
);
1272 ItemT
:= Node
(DconT
);
1275 not Is_OK_Static_Expression
(ItemS
)
1277 not Is_OK_Static_Expression
(ItemT
);
1279 if Expr_Value
(ItemS
) /= Expr_Value
(ItemT
) then
1280 if Do_Access
then -- needs run-time check.
1283 Apply_Compile_Time_Constraint_Error
1284 (N
, "incorrect value for discriminant&?",
1285 CE_Discriminant_Check_Failed
, Ent
=> Discr
);
1292 Next_Discriminant
(Discr
);
1301 -- Here we need a discriminant check. First build the expression
1302 -- for the comparisons of the discriminants:
1304 -- (n.disc1 /= typ.disc1) or else
1305 -- (n.disc2 /= typ.disc2) or else
1307 -- (n.discn /= typ.discn)
1309 Cond
:= Build_Discriminant_Checks
(N
, T_Typ
);
1311 -- If Lhs is set and is a parameter, then the condition is
1312 -- guarded by: lhs'constrained and then (condition built above)
1314 if Present
(Param_Entity
(Lhs
)) then
1318 Make_Attribute_Reference
(Loc
,
1319 Prefix
=> New_Occurrence_Of
(Param_Entity
(Lhs
), Loc
),
1320 Attribute_Name
=> Name_Constrained
),
1321 Right_Opnd
=> Cond
);
1325 Cond
:= Guard_Access
(Cond
, Loc
, N
);
1329 Make_Raise_Constraint_Error
(Loc
,
1331 Reason
=> CE_Discriminant_Check_Failed
));
1332 end Apply_Discriminant_Check
;
1334 ------------------------
1335 -- Apply_Divide_Check --
1336 ------------------------
1338 procedure Apply_Divide_Check
(N
: Node_Id
) is
1339 Loc
: constant Source_Ptr
:= Sloc
(N
);
1340 Typ
: constant Entity_Id
:= Etype
(N
);
1341 Left
: constant Node_Id
:= Left_Opnd
(N
);
1342 Right
: constant Node_Id
:= Right_Opnd
(N
);
1354 and not Backend_Divide_Checks_On_Target
1356 Determine_Range
(Right
, ROK
, Rlo
, Rhi
);
1358 -- See if division by zero possible, and if so generate test. This
1359 -- part of the test is not controlled by the -gnato switch.
1361 if Do_Division_Check
(N
) then
1362 if (not ROK
) or else (Rlo
<= 0 and then 0 <= Rhi
) then
1364 Make_Raise_Constraint_Error
(Loc
,
1367 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(Right
),
1368 Right_Opnd
=> Make_Integer_Literal
(Loc
, 0)),
1369 Reason
=> CE_Divide_By_Zero
));
1373 -- Test for extremely annoying case of xxx'First divided by -1
1375 if Do_Overflow_Check
(N
) then
1377 if Nkind
(N
) = N_Op_Divide
1378 and then Is_Signed_Integer_Type
(Typ
)
1380 Determine_Range
(Left
, LOK
, Llo
, Lhi
);
1381 LLB
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
1383 if ((not ROK
) or else (Rlo
<= (-1) and then (-1) <= Rhi
))
1385 ((not LOK
) or else (Llo
= LLB
))
1388 Make_Raise_Constraint_Error
(Loc
,
1394 Duplicate_Subexpr_Move_Checks
(Left
),
1395 Right_Opnd
=> Make_Integer_Literal
(Loc
, LLB
)),
1399 Duplicate_Subexpr
(Right
),
1401 Make_Integer_Literal
(Loc
, -1))),
1402 Reason
=> CE_Overflow_Check_Failed
));
1407 end Apply_Divide_Check
;
1409 ----------------------------------
1410 -- Apply_Float_Conversion_Check --
1411 ----------------------------------
1413 -- Let F and I be the source and target types of the conversion.
1414 -- The Ada standard specifies that a floating-point value X is rounded
1415 -- to the nearest integer, with halfway cases being rounded away from
1416 -- zero. The rounded value of X is checked against I'Range.
1418 -- The catch in the above paragraph is that there is no good way
1419 -- to know whether the round-to-integer operation resulted in
1420 -- overflow. A remedy is to perform a range check in the floating-point
1421 -- domain instead, however:
1422 -- (1) The bounds may not be known at compile time
1423 -- (2) The check must take into account possible rounding.
1424 -- (3) The range of type I may not be exactly representable in F.
1425 -- (4) The end-points I'First - 0.5 and I'Last + 0.5 may or may
1426 -- not be in range, depending on the sign of I'First and I'Last.
1427 -- (5) X may be a NaN, which will fail any comparison
1429 -- The following steps take care of these issues converting X:
1430 -- (1) If either I'First or I'Last is not known at compile time, use
1431 -- I'Base instead of I in the next three steps and perform a
1432 -- regular range check against I'Range after conversion.
1433 -- (2) If I'First - 0.5 is representable in F then let Lo be that
1434 -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be
1435 -- F'Machine (T) and let Lo_OK be (Lo >= I'First). In other words,
1436 -- take one of the closest floating-point numbers to T, and see if
1437 -- it is in range or not.
1438 -- (3) If I'Last + 0.5 is representable in F then let Hi be that value
1439 -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be
1440 -- F'Rounding (T) and let Hi_OK be (Hi <= I'Last).
1441 -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo)
1442 -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi)
1444 procedure Apply_Float_Conversion_Check
1446 Target_Typ
: Entity_Id
)
1448 LB
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1449 HB
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1450 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1451 Expr_Type
: constant Entity_Id
:= Base_Type
(Etype
(Ck_Node
));
1452 Target_Base
: constant Entity_Id
:= Implementation_Base_Type
1454 Max_Bound
: constant Uint
:= UI_Expon
1455 (Machine_Radix
(Expr_Type
),
1456 Machine_Mantissa
(Expr_Type
) - 1) - 1;
1457 -- Largest bound, so bound plus or minus half is a machine number of F
1460 Ilast
: Uint
; -- Bounds of integer type
1461 Lo
, Hi
: Ureal
; -- Bounds to check in floating-point domain
1463 Hi_OK
: Boolean; -- True iff Lo resp. Hi belongs to I'Range
1466 Hi_Chk
: Node_Id
; -- Expressions that are False iff check fails
1468 Reason
: RT_Exception_Code
;
1471 if not Compile_Time_Known_Value
(LB
)
1472 or not Compile_Time_Known_Value
(HB
)
1475 -- First check that the value falls in the range of the base
1476 -- type, to prevent overflow during conversion and then
1477 -- perform a regular range check against the (dynamic) bounds.
1479 Par
: constant Node_Id
:= Parent
(Ck_Node
);
1481 pragma Assert
(Target_Base
/= Target_Typ
);
1482 pragma Assert
(Nkind
(Par
) = N_Type_Conversion
);
1484 Temp
: constant Entity_Id
:=
1485 Make_Defining_Identifier
(Loc
,
1486 Chars
=> New_Internal_Name
('T'));
1489 Apply_Float_Conversion_Check
(Ck_Node
, Target_Base
);
1490 Set_Etype
(Temp
, Target_Base
);
1492 Insert_Action
(Parent
(Par
),
1493 Make_Object_Declaration
(Loc
,
1494 Defining_Identifier
=> Temp
,
1495 Object_Definition
=> New_Occurrence_Of
(Target_Typ
, Loc
),
1496 Expression
=> New_Copy_Tree
(Par
)),
1497 Suppress
=> All_Checks
);
1500 Make_Raise_Constraint_Error
(Loc
,
1503 Left_Opnd
=> New_Occurrence_Of
(Temp
, Loc
),
1504 Right_Opnd
=> New_Occurrence_Of
(Target_Typ
, Loc
)),
1505 Reason
=> CE_Range_Check_Failed
));
1506 Rewrite
(Par
, New_Occurrence_Of
(Temp
, Loc
));
1512 -- Get the bounds of the target type
1514 Ifirst
:= Expr_Value
(LB
);
1515 Ilast
:= Expr_Value
(HB
);
1517 -- Check against lower bound
1519 if abs (Ifirst
) < Max_Bound
then
1520 Lo
:= UR_From_Uint
(Ifirst
) - Ureal_Half
;
1521 Lo_OK
:= (Ifirst
> 0);
1523 Lo
:= Machine
(Expr_Type
, UR_From_Uint
(Ifirst
), Round_Even
, Ck_Node
);
1524 Lo_OK
:= (Lo
>= UR_From_Uint
(Ifirst
));
1529 -- Lo_Chk := (X >= Lo)
1531 Lo_Chk
:= Make_Op_Ge
(Loc
,
1532 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1533 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
1536 -- Lo_Chk := (X > Lo)
1538 Lo_Chk
:= Make_Op_Gt
(Loc
,
1539 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1540 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
1543 -- Check against higher bound
1545 if abs (Ilast
) < Max_Bound
then
1546 Hi
:= UR_From_Uint
(Ilast
) + Ureal_Half
;
1547 Hi_OK
:= (Ilast
< 0);
1549 Hi
:= Machine
(Expr_Type
, UR_From_Uint
(Ilast
), Round_Even
, Ck_Node
);
1550 Hi_OK
:= (Hi
<= UR_From_Uint
(Ilast
));
1555 -- Hi_Chk := (X <= Hi)
1557 Hi_Chk
:= Make_Op_Le
(Loc
,
1558 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1559 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
1562 -- Hi_Chk := (X < Hi)
1564 Hi_Chk
:= Make_Op_Lt
(Loc
,
1565 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1566 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
1569 -- If the bounds of the target type are the same as those of the
1570 -- base type, the check is an overflow check as a range check is
1571 -- not performed in these cases.
1573 if Expr_Value
(Type_Low_Bound
(Target_Base
)) = Ifirst
1574 and then Expr_Value
(Type_High_Bound
(Target_Base
)) = Ilast
1576 Reason
:= CE_Overflow_Check_Failed
;
1578 Reason
:= CE_Range_Check_Failed
;
1581 -- Raise CE if either conditions does not hold
1583 Insert_Action
(Ck_Node
,
1584 Make_Raise_Constraint_Error
(Loc
,
1585 Condition
=> Make_Op_Not
(Loc
, Make_Op_And
(Loc
, Lo_Chk
, Hi_Chk
)),
1587 end Apply_Float_Conversion_Check
;
1589 ------------------------
1590 -- Apply_Length_Check --
1591 ------------------------
1593 procedure Apply_Length_Check
1595 Target_Typ
: Entity_Id
;
1596 Source_Typ
: Entity_Id
:= Empty
)
1599 Apply_Selected_Length_Checks
1600 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
1601 end Apply_Length_Check
;
1603 -----------------------
1604 -- Apply_Range_Check --
1605 -----------------------
1607 procedure Apply_Range_Check
1609 Target_Typ
: Entity_Id
;
1610 Source_Typ
: Entity_Id
:= Empty
)
1613 Apply_Selected_Range_Checks
1614 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
1615 end Apply_Range_Check
;
1617 ------------------------------
1618 -- Apply_Scalar_Range_Check --
1619 ------------------------------
1621 -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check
1622 -- flag off if it is already set on.
1624 procedure Apply_Scalar_Range_Check
1626 Target_Typ
: Entity_Id
;
1627 Source_Typ
: Entity_Id
:= Empty
;
1628 Fixed_Int
: Boolean := False)
1630 Parnt
: constant Node_Id
:= Parent
(Expr
);
1632 Arr
: Node_Id
:= Empty
; -- initialize to prevent warning
1633 Arr_Typ
: Entity_Id
:= Empty
; -- initialize to prevent warning
1636 Is_Subscr_Ref
: Boolean;
1637 -- Set true if Expr is a subscript
1639 Is_Unconstrained_Subscr_Ref
: Boolean;
1640 -- Set true if Expr is a subscript of an unconstrained array. In this
1641 -- case we do not attempt to do an analysis of the value against the
1642 -- range of the subscript, since we don't know the actual subtype.
1645 -- Set to True if Expr should be regarded as a real value
1646 -- even though the type of Expr might be discrete.
1648 procedure Bad_Value
;
1649 -- Procedure called if value is determined to be out of range
1655 procedure Bad_Value
is
1657 Apply_Compile_Time_Constraint_Error
1658 (Expr
, "value not in range of}?", CE_Range_Check_Failed
,
1663 -- Start of processing for Apply_Scalar_Range_Check
1666 if Inside_A_Generic
then
1669 -- Return if check obviously not needed. Note that we do not check
1670 -- for the expander being inactive, since this routine does not
1671 -- insert any code, but it does generate useful warnings sometimes,
1672 -- which we would like even if we are in semantics only mode.
1674 elsif Target_Typ
= Any_Type
1675 or else not Is_Scalar_Type
(Target_Typ
)
1676 or else Raises_Constraint_Error
(Expr
)
1681 -- Now, see if checks are suppressed
1684 Is_List_Member
(Expr
) and then Nkind
(Parnt
) = N_Indexed_Component
;
1686 if Is_Subscr_Ref
then
1687 Arr
:= Prefix
(Parnt
);
1688 Arr_Typ
:= Get_Actual_Subtype_If_Available
(Arr
);
1691 if not Do_Range_Check
(Expr
) then
1693 -- Subscript reference. Check for Index_Checks suppressed
1695 if Is_Subscr_Ref
then
1697 -- Check array type and its base type
1699 if Index_Checks_Suppressed
(Arr_Typ
)
1700 or else Index_Checks_Suppressed
(Base_Type
(Arr_Typ
))
1704 -- Check array itself if it is an entity name
1706 elsif Is_Entity_Name
(Arr
)
1707 and then Index_Checks_Suppressed
(Entity
(Arr
))
1711 -- Check expression itself if it is an entity name
1713 elsif Is_Entity_Name
(Expr
)
1714 and then Index_Checks_Suppressed
(Entity
(Expr
))
1719 -- All other cases, check for Range_Checks suppressed
1722 -- Check target type and its base type
1724 if Range_Checks_Suppressed
(Target_Typ
)
1725 or else Range_Checks_Suppressed
(Base_Type
(Target_Typ
))
1729 -- Check expression itself if it is an entity name
1731 elsif Is_Entity_Name
(Expr
)
1732 and then Range_Checks_Suppressed
(Entity
(Expr
))
1736 -- If Expr is part of an assignment statement, then check
1737 -- left side of assignment if it is an entity name.
1739 elsif Nkind
(Parnt
) = N_Assignment_Statement
1740 and then Is_Entity_Name
(Name
(Parnt
))
1741 and then Range_Checks_Suppressed
(Entity
(Name
(Parnt
)))
1748 -- Do not set range checks if they are killed
1750 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
1751 and then Kill_Range_Check
(Expr
)
1756 -- Do not set range checks for any values from System.Scalar_Values
1757 -- since the whole idea of such values is to avoid checking them!
1759 if Is_Entity_Name
(Expr
)
1760 and then Is_RTU
(Scope
(Entity
(Expr
)), System_Scalar_Values
)
1765 -- Now see if we need a check
1767 if No
(Source_Typ
) then
1768 S_Typ
:= Etype
(Expr
);
1770 S_Typ
:= Source_Typ
;
1773 if not Is_Scalar_Type
(S_Typ
) or else S_Typ
= Any_Type
then
1777 Is_Unconstrained_Subscr_Ref
:=
1778 Is_Subscr_Ref
and then not Is_Constrained
(Arr_Typ
);
1780 -- Always do a range check if the source type includes infinities
1781 -- and the target type does not include infinities. We do not do
1782 -- this if range checks are killed.
1784 if Is_Floating_Point_Type
(S_Typ
)
1785 and then Has_Infinities
(S_Typ
)
1786 and then not Has_Infinities
(Target_Typ
)
1788 Enable_Range_Check
(Expr
);
1791 -- Return if we know expression is definitely in the range of
1792 -- the target type as determined by Determine_Range. Right now
1793 -- we only do this for discrete types, and not fixed-point or
1794 -- floating-point types.
1796 -- The additional less-precise tests below catch these cases
1798 -- Note: skip this if we are given a source_typ, since the point
1799 -- of supplying a Source_Typ is to stop us looking at the expression.
1800 -- could sharpen this test to be out parameters only ???
1802 if Is_Discrete_Type
(Target_Typ
)
1803 and then Is_Discrete_Type
(Etype
(Expr
))
1804 and then not Is_Unconstrained_Subscr_Ref
1805 and then No
(Source_Typ
)
1808 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1809 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1814 if Compile_Time_Known_Value
(Tlo
)
1815 and then Compile_Time_Known_Value
(Thi
)
1818 Lov
: constant Uint
:= Expr_Value
(Tlo
);
1819 Hiv
: constant Uint
:= Expr_Value
(Thi
);
1822 -- If range is null, we for sure have a constraint error
1823 -- (we don't even need to look at the value involved,
1824 -- since all possible values will raise CE).
1831 -- Otherwise determine range of value
1833 Determine_Range
(Expr
, OK
, Lo
, Hi
);
1837 -- If definitely in range, all OK
1839 if Lo
>= Lov
and then Hi
<= Hiv
then
1842 -- If definitely not in range, warn
1844 elsif Lov
> Hi
or else Hiv
< Lo
then
1848 -- Otherwise we don't know
1860 Is_Floating_Point_Type
(S_Typ
)
1861 or else (Is_Fixed_Point_Type
(S_Typ
) and then not Fixed_Int
);
1863 -- Check if we can determine at compile time whether Expr is in the
1864 -- range of the target type. Note that if S_Typ is within the bounds
1865 -- of Target_Typ then this must be the case. This check is meaningful
1866 -- only if this is not a conversion between integer and real types.
1868 if not Is_Unconstrained_Subscr_Ref
1870 Is_Discrete_Type
(S_Typ
) = Is_Discrete_Type
(Target_Typ
)
1872 (In_Subrange_Of
(S_Typ
, Target_Typ
, Fixed_Int
)
1874 Is_In_Range
(Expr
, Target_Typ
, Fixed_Int
, Int_Real
))
1878 elsif Is_Out_Of_Range
(Expr
, Target_Typ
, Fixed_Int
, Int_Real
) then
1882 -- In the floating-point case, we only do range checks if the
1883 -- type is constrained. We definitely do NOT want range checks
1884 -- for unconstrained types, since we want to have infinities
1886 elsif Is_Floating_Point_Type
(S_Typ
) then
1887 if Is_Constrained
(S_Typ
) then
1888 Enable_Range_Check
(Expr
);
1891 -- For all other cases we enable a range check unconditionally
1894 Enable_Range_Check
(Expr
);
1897 end Apply_Scalar_Range_Check
;
1899 ----------------------------------
1900 -- Apply_Selected_Length_Checks --
1901 ----------------------------------
1903 procedure Apply_Selected_Length_Checks
1905 Target_Typ
: Entity_Id
;
1906 Source_Typ
: Entity_Id
;
1907 Do_Static
: Boolean)
1910 R_Result
: Check_Result
;
1913 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1914 Checks_On
: constant Boolean :=
1915 (not Index_Checks_Suppressed
(Target_Typ
))
1917 (not Length_Checks_Suppressed
(Target_Typ
));
1920 if not Expander_Active
then
1925 Selected_Length_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
1927 for J
in 1 .. 2 loop
1928 R_Cno
:= R_Result
(J
);
1929 exit when No
(R_Cno
);
1931 -- A length check may mention an Itype which is attached to a
1932 -- subsequent node. At the top level in a package this can cause
1933 -- an order-of-elaboration problem, so we make sure that the itype
1934 -- is referenced now.
1936 if Ekind
(Current_Scope
) = E_Package
1937 and then Is_Compilation_Unit
(Current_Scope
)
1939 Ensure_Defined
(Target_Typ
, Ck_Node
);
1941 if Present
(Source_Typ
) then
1942 Ensure_Defined
(Source_Typ
, Ck_Node
);
1944 elsif Is_Itype
(Etype
(Ck_Node
)) then
1945 Ensure_Defined
(Etype
(Ck_Node
), Ck_Node
);
1949 -- If the item is a conditional raise of constraint error,
1950 -- then have a look at what check is being performed and
1953 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
1954 and then Present
(Condition
(R_Cno
))
1956 Cond
:= Condition
(R_Cno
);
1958 if not Has_Dynamic_Length_Check
(Ck_Node
)
1961 Insert_Action
(Ck_Node
, R_Cno
);
1963 if not Do_Static
then
1964 Set_Has_Dynamic_Length_Check
(Ck_Node
);
1968 -- Output a warning if the condition is known to be True
1970 if Is_Entity_Name
(Cond
)
1971 and then Entity
(Cond
) = Standard_True
1973 Apply_Compile_Time_Constraint_Error
1974 (Ck_Node
, "wrong length for array of}?",
1975 CE_Length_Check_Failed
,
1979 -- If we were only doing a static check, or if checks are not
1980 -- on, then we want to delete the check, since it is not needed.
1981 -- We do this by replacing the if statement by a null statement
1983 elsif Do_Static
or else not Checks_On
then
1984 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
1988 Install_Static_Check
(R_Cno
, Loc
);
1993 end Apply_Selected_Length_Checks
;
1995 ---------------------------------
1996 -- Apply_Selected_Range_Checks --
1997 ---------------------------------
1999 procedure Apply_Selected_Range_Checks
2001 Target_Typ
: Entity_Id
;
2002 Source_Typ
: Entity_Id
;
2003 Do_Static
: Boolean)
2006 R_Result
: Check_Result
;
2009 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
2010 Checks_On
: constant Boolean :=
2011 (not Index_Checks_Suppressed
(Target_Typ
))
2013 (not Range_Checks_Suppressed
(Target_Typ
));
2016 if not Expander_Active
or else not Checks_On
then
2021 Selected_Range_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
2023 for J
in 1 .. 2 loop
2025 R_Cno
:= R_Result
(J
);
2026 exit when No
(R_Cno
);
2028 -- If the item is a conditional raise of constraint error,
2029 -- then have a look at what check is being performed and
2032 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
2033 and then Present
(Condition
(R_Cno
))
2035 Cond
:= Condition
(R_Cno
);
2037 if not Has_Dynamic_Range_Check
(Ck_Node
) then
2038 Insert_Action
(Ck_Node
, R_Cno
);
2040 if not Do_Static
then
2041 Set_Has_Dynamic_Range_Check
(Ck_Node
);
2045 -- Output a warning if the condition is known to be True
2047 if Is_Entity_Name
(Cond
)
2048 and then Entity
(Cond
) = Standard_True
2050 -- Since an N_Range is technically not an expression, we
2051 -- have to set one of the bounds to C_E and then just flag
2052 -- the N_Range. The warning message will point to the
2053 -- lower bound and complain about a range, which seems OK.
2055 if Nkind
(Ck_Node
) = N_Range
then
2056 Apply_Compile_Time_Constraint_Error
2057 (Low_Bound
(Ck_Node
), "static range out of bounds of}?",
2058 CE_Range_Check_Failed
,
2062 Set_Raises_Constraint_Error
(Ck_Node
);
2065 Apply_Compile_Time_Constraint_Error
2066 (Ck_Node
, "static value out of range of}?",
2067 CE_Range_Check_Failed
,
2072 -- If we were only doing a static check, or if checks are not
2073 -- on, then we want to delete the check, since it is not needed.
2074 -- We do this by replacing the if statement by a null statement
2076 elsif Do_Static
or else not Checks_On
then
2077 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
2081 Install_Static_Check
(R_Cno
, Loc
);
2084 end Apply_Selected_Range_Checks
;
2086 -------------------------------
2087 -- Apply_Static_Length_Check --
2088 -------------------------------
2090 procedure Apply_Static_Length_Check
2092 Target_Typ
: Entity_Id
;
2093 Source_Typ
: Entity_Id
:= Empty
)
2096 Apply_Selected_Length_Checks
2097 (Expr
, Target_Typ
, Source_Typ
, Do_Static
=> True);
2098 end Apply_Static_Length_Check
;
2100 -------------------------------------
2101 -- Apply_Subscript_Validity_Checks --
2102 -------------------------------------
2104 procedure Apply_Subscript_Validity_Checks
(Expr
: Node_Id
) is
2108 pragma Assert
(Nkind
(Expr
) = N_Indexed_Component
);
2110 -- Loop through subscripts
2112 Sub
:= First
(Expressions
(Expr
));
2113 while Present
(Sub
) loop
2115 -- Check one subscript. Note that we do not worry about
2116 -- enumeration type with holes, since we will convert the
2117 -- value to a Pos value for the subscript, and that convert
2118 -- will do the necessary validity check.
2120 Ensure_Valid
(Sub
, Holes_OK
=> True);
2122 -- Move to next subscript
2126 end Apply_Subscript_Validity_Checks
;
2128 ----------------------------------
2129 -- Apply_Type_Conversion_Checks --
2130 ----------------------------------
2132 procedure Apply_Type_Conversion_Checks
(N
: Node_Id
) is
2133 Target_Type
: constant Entity_Id
:= Etype
(N
);
2134 Target_Base
: constant Entity_Id
:= Base_Type
(Target_Type
);
2135 Expr
: constant Node_Id
:= Expression
(N
);
2136 Expr_Type
: constant Entity_Id
:= Etype
(Expr
);
2139 if Inside_A_Generic
then
2142 -- Skip these checks if serious errors detected, there are some nasty
2143 -- situations of incomplete trees that blow things up.
2145 elsif Serious_Errors_Detected
> 0 then
2148 -- Scalar type conversions of the form Target_Type (Expr) require
2149 -- a range check if we cannot be sure that Expr is in the base type
2150 -- of Target_Typ and also that Expr is in the range of Target_Typ.
2151 -- These are not quite the same condition from an implementation
2152 -- point of view, but clearly the second includes the first.
2154 elsif Is_Scalar_Type
(Target_Type
) then
2156 Conv_OK
: constant Boolean := Conversion_OK
(N
);
2157 -- If the Conversion_OK flag on the type conversion is set
2158 -- and no floating point type is involved in the type conversion
2159 -- then fixed point values must be read as integral values.
2161 Float_To_Int
: constant Boolean :=
2162 Is_Floating_Point_Type
(Expr_Type
)
2163 and then Is_Integer_Type
(Target_Type
);
2166 if not Overflow_Checks_Suppressed
(Target_Base
)
2167 and then not In_Subrange_Of
(Expr_Type
, Target_Base
, Conv_OK
)
2168 and then not Float_To_Int
2170 Set_Do_Overflow_Check
(N
);
2173 if not Range_Checks_Suppressed
(Target_Type
)
2174 and then not Range_Checks_Suppressed
(Expr_Type
)
2176 if Float_To_Int
then
2177 Apply_Float_Conversion_Check
(Expr
, Target_Type
);
2179 Apply_Scalar_Range_Check
2180 (Expr
, Target_Type
, Fixed_Int
=> Conv_OK
);
2185 elsif Comes_From_Source
(N
)
2186 and then Is_Record_Type
(Target_Type
)
2187 and then Is_Derived_Type
(Target_Type
)
2188 and then not Is_Tagged_Type
(Target_Type
)
2189 and then not Is_Constrained
(Target_Type
)
2190 and then Present
(Stored_Constraint
(Target_Type
))
2192 -- An unconstrained derived type may have inherited discriminant
2193 -- Build an actual discriminant constraint list using the stored
2194 -- constraint, to verify that the expression of the parent type
2195 -- satisfies the constraints imposed by the (unconstrained!)
2196 -- derived type. This applies to value conversions, not to view
2197 -- conversions of tagged types.
2200 Loc
: constant Source_Ptr
:= Sloc
(N
);
2202 Constraint
: Elmt_Id
;
2203 Discr_Value
: Node_Id
;
2206 New_Constraints
: constant Elist_Id
:= New_Elmt_List
;
2207 Old_Constraints
: constant Elist_Id
:=
2208 Discriminant_Constraint
(Expr_Type
);
2211 Constraint
:= First_Elmt
(Stored_Constraint
(Target_Type
));
2213 while Present
(Constraint
) loop
2214 Discr_Value
:= Node
(Constraint
);
2216 if Is_Entity_Name
(Discr_Value
)
2217 and then Ekind
(Entity
(Discr_Value
)) = E_Discriminant
2219 Discr
:= Corresponding_Discriminant
(Entity
(Discr_Value
));
2222 and then Scope
(Discr
) = Base_Type
(Expr_Type
)
2224 -- Parent is constrained by new discriminant. Obtain
2225 -- Value of original discriminant in expression. If
2226 -- the new discriminant has been used to constrain more
2227 -- than one of the stored discriminants, this will
2228 -- provide the required consistency check.
2231 Make_Selected_Component
(Loc
,
2233 Duplicate_Subexpr_No_Checks
2234 (Expr
, Name_Req
=> True),
2236 Make_Identifier
(Loc
, Chars
(Discr
))),
2240 -- Discriminant of more remote ancestor ???
2245 -- Derived type definition has an explicit value for
2246 -- this stored discriminant.
2250 (Duplicate_Subexpr_No_Checks
(Discr_Value
),
2254 Next_Elmt
(Constraint
);
2257 -- Use the unconstrained expression type to retrieve the
2258 -- discriminants of the parent, and apply momentarily the
2259 -- discriminant constraint synthesized above.
2261 Set_Discriminant_Constraint
(Expr_Type
, New_Constraints
);
2262 Cond
:= Build_Discriminant_Checks
(Expr
, Expr_Type
);
2263 Set_Discriminant_Constraint
(Expr_Type
, Old_Constraints
);
2266 Make_Raise_Constraint_Error
(Loc
,
2268 Reason
=> CE_Discriminant_Check_Failed
));
2271 -- For arrays, conversions are applied during expansion, to take
2272 -- into accounts changes of representation. The checks become range
2273 -- checks on the base type or length checks on the subtype, depending
2274 -- on whether the target type is unconstrained or constrained.
2279 end Apply_Type_Conversion_Checks
;
2281 ----------------------------------------------
2282 -- Apply_Universal_Integer_Attribute_Checks --
2283 ----------------------------------------------
2285 procedure Apply_Universal_Integer_Attribute_Checks
(N
: Node_Id
) is
2286 Loc
: constant Source_Ptr
:= Sloc
(N
);
2287 Typ
: constant Entity_Id
:= Etype
(N
);
2290 if Inside_A_Generic
then
2293 -- Nothing to do if checks are suppressed
2295 elsif Range_Checks_Suppressed
(Typ
)
2296 and then Overflow_Checks_Suppressed
(Typ
)
2300 -- Nothing to do if the attribute does not come from source. The
2301 -- internal attributes we generate of this type do not need checks,
2302 -- and furthermore the attempt to check them causes some circular
2303 -- elaboration orders when dealing with packed types.
2305 elsif not Comes_From_Source
(N
) then
2308 -- If the prefix is a selected component that depends on a discriminant
2309 -- the check may improperly expose a discriminant instead of using
2310 -- the bounds of the object itself. Set the type of the attribute to
2311 -- the base type of the context, so that a check will be imposed when
2312 -- needed (e.g. if the node appears as an index).
2314 elsif Nkind
(Prefix
(N
)) = N_Selected_Component
2315 and then Ekind
(Typ
) = E_Signed_Integer_Subtype
2316 and then Depends_On_Discriminant
(Scalar_Range
(Typ
))
2318 Set_Etype
(N
, Base_Type
(Typ
));
2320 -- Otherwise, replace the attribute node with a type conversion
2321 -- node whose expression is the attribute, retyped to universal
2322 -- integer, and whose subtype mark is the target type. The call
2323 -- to analyze this conversion will set range and overflow checks
2324 -- as required for proper detection of an out of range value.
2327 Set_Etype
(N
, Universal_Integer
);
2328 Set_Analyzed
(N
, True);
2331 Make_Type_Conversion
(Loc
,
2332 Subtype_Mark
=> New_Occurrence_Of
(Typ
, Loc
),
2333 Expression
=> Relocate_Node
(N
)));
2335 Analyze_And_Resolve
(N
, Typ
);
2339 end Apply_Universal_Integer_Attribute_Checks
;
2341 -------------------------------
2342 -- Build_Discriminant_Checks --
2343 -------------------------------
2345 function Build_Discriminant_Checks
2347 T_Typ
: Entity_Id
) return Node_Id
2349 Loc
: constant Source_Ptr
:= Sloc
(N
);
2352 Disc_Ent
: Entity_Id
;
2358 Disc
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
2360 -- For a fully private type, use the discriminants of the parent type
2362 if Is_Private_Type
(T_Typ
)
2363 and then No
(Full_View
(T_Typ
))
2365 Disc_Ent
:= First_Discriminant
(Etype
(Base_Type
(T_Typ
)));
2367 Disc_Ent
:= First_Discriminant
(T_Typ
);
2370 while Present
(Disc
) loop
2371 Dval
:= Node
(Disc
);
2373 if Nkind
(Dval
) = N_Identifier
2374 and then Ekind
(Entity
(Dval
)) = E_Discriminant
2376 Dval
:= New_Occurrence_Of
(Discriminal
(Entity
(Dval
)), Loc
);
2378 Dval
:= Duplicate_Subexpr_No_Checks
(Dval
);
2381 -- If we have an Unchecked_Union node, we can infer the discriminants
2384 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
2386 Get_Discriminant_Value
(
2387 First_Discriminant
(T_Typ
),
2389 Stored_Constraint
(T_Typ
)));
2393 Make_Selected_Component
(Loc
,
2395 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
2397 Make_Identifier
(Loc
, Chars
(Disc_Ent
)));
2399 Set_Is_In_Discriminant_Check
(Dref
);
2402 Evolve_Or_Else
(Cond
,
2405 Right_Opnd
=> Dval
));
2408 Next_Discriminant
(Disc_Ent
);
2412 end Build_Discriminant_Checks
;
2414 -----------------------------------
2415 -- Check_Valid_Lvalue_Subscripts --
2416 -----------------------------------
2418 procedure Check_Valid_Lvalue_Subscripts
(Expr
: Node_Id
) is
2420 -- Skip this if range checks are suppressed
2422 if Range_Checks_Suppressed
(Etype
(Expr
)) then
2425 -- Only do this check for expressions that come from source. We
2426 -- assume that expander generated assignments explicitly include
2427 -- any necessary checks. Note that this is not just an optimization,
2428 -- it avoids infinite recursions!
2430 elsif not Comes_From_Source
(Expr
) then
2433 -- For a selected component, check the prefix
2435 elsif Nkind
(Expr
) = N_Selected_Component
then
2436 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
2439 -- Case of indexed component
2441 elsif Nkind
(Expr
) = N_Indexed_Component
then
2442 Apply_Subscript_Validity_Checks
(Expr
);
2444 -- Prefix may itself be or contain an indexed component, and
2445 -- these subscripts need checking as well
2447 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
2449 end Check_Valid_Lvalue_Subscripts
;
2451 ----------------------------------
2452 -- Null_Exclusion_Static_Checks --
2453 ----------------------------------
2455 procedure Null_Exclusion_Static_Checks
(N
: Node_Id
) is
2456 K
: constant Node_Kind
:= Nkind
(N
);
2458 Related_Nod
: Node_Id
;
2459 Has_Null_Exclusion
: Boolean := False;
2461 type Msg_Kind
is (Components
, Formals
, Objects
);
2462 Msg_K
: Msg_Kind
:= Objects
;
2463 -- Used by local subprograms to generate precise error messages
2465 procedure Check_Must_Be_Access
2467 Has_Null_Exclusion
: Boolean);
2468 -- ??? local subprograms must have comment on spec
2470 procedure Check_Already_Null_Excluding_Type
2472 Has_Null_Exclusion
: Boolean;
2473 Related_Nod
: Node_Id
);
2474 -- ??? local subprograms must have comment on spec
2476 procedure Check_Must_Be_Initialized
2478 Related_Nod
: Node_Id
);
2479 -- ??? local subprograms must have comment on spec
2481 procedure Check_Null_Not_Allowed
(N
: Node_Id
);
2482 -- ??? local subprograms must have comment on spec
2484 -- ??? following bodies lack comments
2486 --------------------------
2487 -- Check_Must_Be_Access --
2488 --------------------------
2490 procedure Check_Must_Be_Access
2492 Has_Null_Exclusion
: Boolean)
2495 if Has_Null_Exclusion
2496 and then not Is_Access_Type
(Typ
)
2498 Error_Msg_N
("(Ada 2005) must be an access type", Related_Nod
);
2500 end Check_Must_Be_Access
;
2502 ---------------------------------------
2503 -- Check_Already_Null_Excluding_Type --
2504 ---------------------------------------
2506 procedure Check_Already_Null_Excluding_Type
2508 Has_Null_Exclusion
: Boolean;
2509 Related_Nod
: Node_Id
)
2512 if Has_Null_Exclusion
2513 and then Can_Never_Be_Null
(Typ
)
2516 ("(Ada 2005) already a null-excluding type", Related_Nod
);
2518 end Check_Already_Null_Excluding_Type
;
2520 -------------------------------
2521 -- Check_Must_Be_Initialized --
2522 -------------------------------
2524 procedure Check_Must_Be_Initialized
2526 Related_Nod
: Node_Id
)
2528 Expr
: constant Node_Id
:= Expression
(N
);
2531 pragma Assert
(Nkind
(N
) = N_Component_Declaration
2532 or else Nkind
(N
) = N_Object_Declaration
);
2534 if not Present
(Expr
) then
2538 ("(Ada 2005) null-excluding components must be " &
2539 "initialized", Related_Nod
);
2543 ("(Ada 2005) null-excluding formals must be initialized",
2548 ("(Ada 2005) null-excluding objects must be initialized",
2552 end Check_Must_Be_Initialized
;
2554 ----------------------------
2555 -- Check_Null_Not_Allowed --
2556 ----------------------------
2558 procedure Check_Null_Not_Allowed
(N
: Node_Id
) is
2559 Expr
: constant Node_Id
:= Expression
(N
);
2563 and then Nkind
(Expr
) = N_Null
2567 Apply_Compile_Time_Constraint_Error
2569 Msg
=> "(Ada 2005) NULL not allowed in"
2570 & " null-excluding components?",
2571 Reason
=> CE_Null_Not_Allowed
,
2575 Apply_Compile_Time_Constraint_Error
2577 Msg
=> "(Ada 2005) NULL not allowed in"
2578 & " null-excluding formals?",
2579 Reason
=> CE_Null_Not_Allowed
,
2583 Apply_Compile_Time_Constraint_Error
2585 Msg
=> "(Ada 2005) NULL not allowed in"
2586 & " null-excluding objects?",
2587 Reason
=> CE_Null_Not_Allowed
,
2591 end Check_Null_Not_Allowed
;
2593 -- Start of processing for Null_Exclusion_Static_Checks
2596 pragma Assert
(K
= N_Component_Declaration
2597 or else K
= N_Parameter_Specification
2598 or else K
= N_Object_Declaration
2599 or else K
= N_Discriminant_Specification
2600 or else K
= N_Allocator
);
2603 when N_Component_Declaration
=>
2604 Msg_K
:= Components
;
2606 if not Present
(Access_Definition
(Component_Definition
(N
))) then
2607 Has_Null_Exclusion
:= Null_Exclusion_Present
2608 (Component_Definition
(N
));
2609 Typ
:= Etype
(Subtype_Indication
(Component_Definition
(N
)));
2610 Related_Nod
:= Subtype_Indication
(Component_Definition
(N
));
2611 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2612 Check_Already_Null_Excluding_Type
2613 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2614 Check_Must_Be_Initialized
(N
, Related_Nod
);
2617 Check_Null_Not_Allowed
(N
);
2619 when N_Parameter_Specification
=>
2621 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2622 Typ
:= Entity
(Parameter_Type
(N
));
2623 Related_Nod
:= Parameter_Type
(N
);
2624 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2625 Check_Already_Null_Excluding_Type
2626 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2627 Check_Null_Not_Allowed
(N
);
2629 when N_Object_Declaration
=>
2631 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2632 Typ
:= Entity
(Object_Definition
(N
));
2633 Related_Nod
:= Object_Definition
(N
);
2634 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2635 Check_Already_Null_Excluding_Type
2636 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2637 Check_Must_Be_Initialized
(N
, Related_Nod
);
2638 Check_Null_Not_Allowed
(N
);
2640 when N_Discriminant_Specification
=>
2641 Msg_K
:= Components
;
2643 if Nkind
(Discriminant_Type
(N
)) /= N_Access_Definition
then
2644 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2645 Typ
:= Etype
(Defining_Identifier
(N
));
2646 Related_Nod
:= Discriminant_Type
(N
);
2647 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2648 Check_Already_Null_Excluding_Type
2649 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2652 Check_Null_Not_Allowed
(N
);
2656 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2657 Typ
:= Etype
(Expression
(N
));
2659 if Nkind
(Expression
(N
)) = N_Qualified_Expression
then
2660 Related_Nod
:= Subtype_Mark
(Expression
(N
));
2662 Related_Nod
:= Expression
(N
);
2665 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2666 Check_Already_Null_Excluding_Type
2667 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2668 Check_Null_Not_Allowed
(N
);
2671 raise Program_Error
;
2673 end Null_Exclusion_Static_Checks
;
2675 ----------------------------------
2676 -- Conditional_Statements_Begin --
2677 ----------------------------------
2679 procedure Conditional_Statements_Begin
is
2681 Saved_Checks_TOS
:= Saved_Checks_TOS
+ 1;
2683 -- If stack overflows, kill all checks, that way we know to
2684 -- simply reset the number of saved checks to zero on return.
2685 -- This should never occur in practice.
2687 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
2690 -- In the normal case, we just make a new stack entry saving
2691 -- the current number of saved checks for a later restore.
2694 Saved_Checks_Stack
(Saved_Checks_TOS
) := Num_Saved_Checks
;
2696 if Debug_Flag_CC
then
2697 w
("Conditional_Statements_Begin: Num_Saved_Checks = ",
2701 end Conditional_Statements_Begin
;
2703 --------------------------------
2704 -- Conditional_Statements_End --
2705 --------------------------------
2707 procedure Conditional_Statements_End
is
2709 pragma Assert
(Saved_Checks_TOS
> 0);
2711 -- If the saved checks stack overflowed, then we killed all
2712 -- checks, so setting the number of saved checks back to
2713 -- zero is correct. This should never occur in practice.
2715 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
2716 Num_Saved_Checks
:= 0;
2718 -- In the normal case, restore the number of saved checks
2719 -- from the top stack entry.
2722 Num_Saved_Checks
:= Saved_Checks_Stack
(Saved_Checks_TOS
);
2723 if Debug_Flag_CC
then
2724 w
("Conditional_Statements_End: Num_Saved_Checks = ",
2729 Saved_Checks_TOS
:= Saved_Checks_TOS
- 1;
2730 end Conditional_Statements_End
;
2732 ---------------------
2733 -- Determine_Range --
2734 ---------------------
2736 Cache_Size
: constant := 2 ** 10;
2737 type Cache_Index
is range 0 .. Cache_Size
- 1;
2738 -- Determine size of below cache (power of 2 is more efficient!)
2740 Determine_Range_Cache_N
: array (Cache_Index
) of Node_Id
;
2741 Determine_Range_Cache_Lo
: array (Cache_Index
) of Uint
;
2742 Determine_Range_Cache_Hi
: array (Cache_Index
) of Uint
;
2743 -- The above arrays are used to implement a small direct cache
2744 -- for Determine_Range calls. Because of the way Determine_Range
2745 -- recursively traces subexpressions, and because overflow checking
2746 -- calls the routine on the way up the tree, a quadratic behavior
2747 -- can otherwise be encountered in large expressions. The cache
2748 -- entry for node N is stored in the (N mod Cache_Size) entry, and
2749 -- can be validated by checking the actual node value stored there.
2751 procedure Determine_Range
2757 Typ
: constant Entity_Id
:= Etype
(N
);
2761 -- Lo and Hi bounds of left operand
2765 -- Lo and Hi bounds of right (or only) operand
2768 -- Temp variable used to hold a bound node
2771 -- High bound of base type of expression
2775 -- Refined values for low and high bounds, after tightening
2778 -- Used in lower level calls to indicate if call succeeded
2780 Cindex
: Cache_Index
;
2781 -- Used to search cache
2783 function OK_Operands
return Boolean;
2784 -- Used for binary operators. Determines the ranges of the left and
2785 -- right operands, and if they are both OK, returns True, and puts
2786 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left
2792 function OK_Operands
return Boolean is
2794 Determine_Range
(Left_Opnd
(N
), OK1
, Lo_Left
, Hi_Left
);
2800 Determine_Range
(Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
);
2804 -- Start of processing for Determine_Range
2807 -- Prevent junk warnings by initializing range variables
2814 -- If the type is not discrete, or is undefined, then we can't
2815 -- do anything about determining the range.
2817 if No
(Typ
) or else not Is_Discrete_Type
(Typ
)
2818 or else Error_Posted
(N
)
2824 -- For all other cases, we can determine the range
2828 -- If value is compile time known, then the possible range is the
2829 -- one value that we know this expression definitely has!
2831 if Compile_Time_Known_Value
(N
) then
2832 Lo
:= Expr_Value
(N
);
2837 -- Return if already in the cache
2839 Cindex
:= Cache_Index
(N
mod Cache_Size
);
2841 if Determine_Range_Cache_N
(Cindex
) = N
then
2842 Lo
:= Determine_Range_Cache_Lo
(Cindex
);
2843 Hi
:= Determine_Range_Cache_Hi
(Cindex
);
2847 -- Otherwise, start by finding the bounds of the type of the
2848 -- expression, the value cannot be outside this range (if it
2849 -- is, then we have an overflow situation, which is a separate
2850 -- check, we are talking here only about the expression value).
2852 -- We use the actual bound unless it is dynamic, in which case
2853 -- use the corresponding base type bound if possible. If we can't
2854 -- get a bound then we figure we can't determine the range (a
2855 -- peculiar case, that perhaps cannot happen, but there is no
2856 -- point in bombing in this optimization circuit.
2858 -- First the low bound
2860 Bound
:= Type_Low_Bound
(Typ
);
2862 if Compile_Time_Known_Value
(Bound
) then
2863 Lo
:= Expr_Value
(Bound
);
2865 elsif Compile_Time_Known_Value
(Type_Low_Bound
(Base_Type
(Typ
))) then
2866 Lo
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
2873 -- Now the high bound
2875 Bound
:= Type_High_Bound
(Typ
);
2877 -- We need the high bound of the base type later on, and this should
2878 -- always be compile time known. Again, it is not clear that this
2879 -- can ever be false, but no point in bombing.
2881 if Compile_Time_Known_Value
(Type_High_Bound
(Base_Type
(Typ
))) then
2882 Hbound
:= Expr_Value
(Type_High_Bound
(Base_Type
(Typ
)));
2890 -- If we have a static subtype, then that may have a tighter bound
2891 -- so use the upper bound of the subtype instead in this case.
2893 if Compile_Time_Known_Value
(Bound
) then
2894 Hi
:= Expr_Value
(Bound
);
2897 -- We may be able to refine this value in certain situations. If
2898 -- refinement is possible, then Lor and Hir are set to possibly
2899 -- tighter bounds, and OK1 is set to True.
2903 -- For unary plus, result is limited by range of operand
2906 Determine_Range
(Right_Opnd
(N
), OK1
, Lor
, Hir
);
2908 -- For unary minus, determine range of operand, and negate it
2911 Determine_Range
(Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
);
2918 -- For binary addition, get range of each operand and do the
2919 -- addition to get the result range.
2923 Lor
:= Lo_Left
+ Lo_Right
;
2924 Hir
:= Hi_Left
+ Hi_Right
;
2927 -- Division is tricky. The only case we consider is where the
2928 -- right operand is a positive constant, and in this case we
2929 -- simply divide the bounds of the left operand
2933 if Lo_Right
= Hi_Right
2934 and then Lo_Right
> 0
2936 Lor
:= Lo_Left
/ Lo_Right
;
2937 Hir
:= Hi_Left
/ Lo_Right
;
2944 -- For binary subtraction, get range of each operand and do
2945 -- the worst case subtraction to get the result range.
2947 when N_Op_Subtract
=>
2949 Lor
:= Lo_Left
- Hi_Right
;
2950 Hir
:= Hi_Left
- Lo_Right
;
2953 -- For MOD, if right operand is a positive constant, then
2954 -- result must be in the allowable range of mod results.
2958 if Lo_Right
= Hi_Right
2959 and then Lo_Right
/= 0
2961 if Lo_Right
> 0 then
2963 Hir
:= Lo_Right
- 1;
2965 else -- Lo_Right < 0
2966 Lor
:= Lo_Right
+ 1;
2975 -- For REM, if right operand is a positive constant, then
2976 -- result must be in the allowable range of mod results.
2980 if Lo_Right
= Hi_Right
2981 and then Lo_Right
/= 0
2984 Dval
: constant Uint
:= (abs Lo_Right
) - 1;
2987 -- The sign of the result depends on the sign of the
2988 -- dividend (but not on the sign of the divisor, hence
2989 -- the abs operation above).
3009 -- Attribute reference cases
3011 when N_Attribute_Reference
=>
3012 case Attribute_Name
(N
) is
3014 -- For Pos/Val attributes, we can refine the range using the
3015 -- possible range of values of the attribute expression
3017 when Name_Pos | Name_Val
=>
3018 Determine_Range
(First
(Expressions
(N
)), OK1
, Lor
, Hir
);
3020 -- For Length attribute, use the bounds of the corresponding
3021 -- index type to refine the range.
3025 Atyp
: Entity_Id
:= Etype
(Prefix
(N
));
3033 if Is_Access_Type
(Atyp
) then
3034 Atyp
:= Designated_Type
(Atyp
);
3037 -- For string literal, we know exact value
3039 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
3041 Lo
:= String_Literal_Length
(Atyp
);
3042 Hi
:= String_Literal_Length
(Atyp
);
3046 -- Otherwise check for expression given
3048 if No
(Expressions
(N
)) then
3052 UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
3055 Indx
:= First_Index
(Atyp
);
3056 for J
in 2 .. Inum
loop
3057 Indx
:= Next_Index
(Indx
);
3061 (Type_Low_Bound
(Etype
(Indx
)), OK1
, LL
, LU
);
3065 (Type_High_Bound
(Etype
(Indx
)), OK1
, UL
, UU
);
3069 -- The maximum value for Length is the biggest
3070 -- possible gap between the values of the bounds.
3071 -- But of course, this value cannot be negative.
3073 Hir
:= UI_Max
(Uint_0
, UU
- LL
);
3075 -- For constrained arrays, the minimum value for
3076 -- Length is taken from the actual value of the
3077 -- bounds, since the index will be exactly of
3080 if Is_Constrained
(Atyp
) then
3081 Lor
:= UI_Max
(Uint_0
, UL
- LU
);
3083 -- For an unconstrained array, the minimum value
3084 -- for length is always zero.
3093 -- No special handling for other attributes
3094 -- Probably more opportunities exist here ???
3101 -- For type conversion from one discrete type to another, we
3102 -- can refine the range using the converted value.
3104 when N_Type_Conversion
=>
3105 Determine_Range
(Expression
(N
), OK1
, Lor
, Hir
);
3107 -- Nothing special to do for all other expression kinds
3115 -- At this stage, if OK1 is true, then we know that the actual
3116 -- result of the computed expression is in the range Lor .. Hir.
3117 -- We can use this to restrict the possible range of results.
3121 -- If the refined value of the low bound is greater than the
3122 -- type high bound, then reset it to the more restrictive
3123 -- value. However, we do NOT do this for the case of a modular
3124 -- type where the possible upper bound on the value is above the
3125 -- base type high bound, because that means the result could wrap.
3128 and then not (Is_Modular_Integer_Type
(Typ
)
3129 and then Hir
> Hbound
)
3134 -- Similarly, if the refined value of the high bound is less
3135 -- than the value so far, then reset it to the more restrictive
3136 -- value. Again, we do not do this if the refined low bound is
3137 -- negative for a modular type, since this would wrap.
3140 and then not (Is_Modular_Integer_Type
(Typ
)
3141 and then Lor
< Uint_0
)
3147 -- Set cache entry for future call and we are all done
3149 Determine_Range_Cache_N
(Cindex
) := N
;
3150 Determine_Range_Cache_Lo
(Cindex
) := Lo
;
3151 Determine_Range_Cache_Hi
(Cindex
) := Hi
;
3154 -- If any exception occurs, it means that we have some bug in the compiler
3155 -- possibly triggered by a previous error, or by some unforseen peculiar
3156 -- occurrence. However, this is only an optimization attempt, so there is
3157 -- really no point in crashing the compiler. Instead we just decide, too
3158 -- bad, we can't figure out a range in this case after all.
3163 -- Debug flag K disables this behavior (useful for debugging)
3165 if Debug_Flag_K
then
3173 end Determine_Range
;
3175 ------------------------------------
3176 -- Discriminant_Checks_Suppressed --
3177 ------------------------------------
3179 function Discriminant_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3182 if Is_Unchecked_Union
(E
) then
3184 elsif Checks_May_Be_Suppressed
(E
) then
3185 return Is_Check_Suppressed
(E
, Discriminant_Check
);
3189 return Scope_Suppress
(Discriminant_Check
);
3190 end Discriminant_Checks_Suppressed
;
3192 --------------------------------
3193 -- Division_Checks_Suppressed --
3194 --------------------------------
3196 function Division_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3198 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
3199 return Is_Check_Suppressed
(E
, Division_Check
);
3201 return Scope_Suppress
(Division_Check
);
3203 end Division_Checks_Suppressed
;
3205 -----------------------------------
3206 -- Elaboration_Checks_Suppressed --
3207 -----------------------------------
3209 function Elaboration_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3212 if Kill_Elaboration_Checks
(E
) then
3214 elsif Checks_May_Be_Suppressed
(E
) then
3215 return Is_Check_Suppressed
(E
, Elaboration_Check
);
3219 return Scope_Suppress
(Elaboration_Check
);
3220 end Elaboration_Checks_Suppressed
;
3222 ---------------------------
3223 -- Enable_Overflow_Check --
3224 ---------------------------
3226 procedure Enable_Overflow_Check
(N
: Node_Id
) is
3227 Typ
: constant Entity_Id
:= Base_Type
(Etype
(N
));
3236 if Debug_Flag_CC
then
3237 w
("Enable_Overflow_Check for node ", Int
(N
));
3238 Write_Str
(" Source location = ");
3243 -- Nothing to do if the range of the result is known OK. We skip
3244 -- this for conversions, since the caller already did the check,
3245 -- and in any case the condition for deleting the check for a
3246 -- type conversion is different in any case.
3248 if Nkind
(N
) /= N_Type_Conversion
then
3249 Determine_Range
(N
, OK
, Lo
, Hi
);
3251 -- Note in the test below that we assume that if a bound of the
3252 -- range is equal to that of the type. That's not quite accurate
3253 -- but we do this for the following reasons:
3255 -- a) The way that Determine_Range works, it will typically report
3256 -- the bounds of the value as being equal to the bounds of the
3257 -- type, because it either can't tell anything more precise, or
3258 -- does not think it is worth the effort to be more precise.
3260 -- b) It is very unusual to have a situation in which this would
3261 -- generate an unnecessary overflow check (an example would be
3262 -- a subtype with a range 0 .. Integer'Last - 1 to which the
3263 -- literal value one is added.
3265 -- c) The alternative is a lot of special casing in this routine
3266 -- which would partially duplicate Determine_Range processing.
3269 and then Lo
> Expr_Value
(Type_Low_Bound
(Typ
))
3270 and then Hi
< Expr_Value
(Type_High_Bound
(Typ
))
3272 if Debug_Flag_CC
then
3273 w
("No overflow check required");
3280 -- If not in optimizing mode, set flag and we are done. We are also
3281 -- done (and just set the flag) if the type is not a discrete type,
3282 -- since it is not worth the effort to eliminate checks for other
3283 -- than discrete types. In addition, we take this same path if we
3284 -- have stored the maximum number of checks possible already (a
3285 -- very unlikely situation, but we do not want to blow up!)
3287 if Optimization_Level
= 0
3288 or else not Is_Discrete_Type
(Etype
(N
))
3289 or else Num_Saved_Checks
= Saved_Checks
'Last
3291 Set_Do_Overflow_Check
(N
, True);
3293 if Debug_Flag_CC
then
3294 w
("Optimization off");
3300 -- Otherwise evaluate and check the expression
3305 Target_Type
=> Empty
,
3311 if Debug_Flag_CC
then
3312 w
("Called Find_Check");
3316 w
(" Check_Num = ", Chk
);
3317 w
(" Ent = ", Int
(Ent
));
3318 Write_Str
(" Ofs = ");
3323 -- If check is not of form to optimize, then set flag and we are done
3326 Set_Do_Overflow_Check
(N
, True);
3330 -- If check is already performed, then return without setting flag
3333 if Debug_Flag_CC
then
3334 w
("Check suppressed!");
3340 -- Here we will make a new entry for the new check
3342 Set_Do_Overflow_Check
(N
, True);
3343 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
3344 Saved_Checks
(Num_Saved_Checks
) :=
3349 Target_Type
=> Empty
);
3351 if Debug_Flag_CC
then
3352 w
("Make new entry, check number = ", Num_Saved_Checks
);
3353 w
(" Entity = ", Int
(Ent
));
3354 Write_Str
(" Offset = ");
3356 w
(" Check_Type = O");
3357 w
(" Target_Type = Empty");
3360 -- If we get an exception, then something went wrong, probably because
3361 -- of an error in the structure of the tree due to an incorrect program.
3362 -- Or it may be a bug in the optimization circuit. In either case the
3363 -- safest thing is simply to set the check flag unconditionally.
3367 Set_Do_Overflow_Check
(N
, True);
3369 if Debug_Flag_CC
then
3370 w
(" exception occurred, overflow flag set");
3374 end Enable_Overflow_Check
;
3376 ------------------------
3377 -- Enable_Range_Check --
3378 ------------------------
3380 procedure Enable_Range_Check
(N
: Node_Id
) is
3389 -- Return if unchecked type conversion with range check killed.
3390 -- In this case we never set the flag (that's what Kill_Range_Check
3393 if Nkind
(N
) = N_Unchecked_Type_Conversion
3394 and then Kill_Range_Check
(N
)
3399 -- Debug trace output
3401 if Debug_Flag_CC
then
3402 w
("Enable_Range_Check for node ", Int
(N
));
3403 Write_Str
(" Source location = ");
3408 -- If not in optimizing mode, set flag and we are done. We are also
3409 -- done (and just set the flag) if the type is not a discrete type,
3410 -- since it is not worth the effort to eliminate checks for other
3411 -- than discrete types. In addition, we take this same path if we
3412 -- have stored the maximum number of checks possible already (a
3413 -- very unlikely situation, but we do not want to blow up!)
3415 if Optimization_Level
= 0
3416 or else No
(Etype
(N
))
3417 or else not Is_Discrete_Type
(Etype
(N
))
3418 or else Num_Saved_Checks
= Saved_Checks
'Last
3420 Set_Do_Range_Check
(N
, True);
3422 if Debug_Flag_CC
then
3423 w
("Optimization off");
3429 -- Otherwise find out the target type
3433 -- For assignment, use left side subtype
3435 if Nkind
(P
) = N_Assignment_Statement
3436 and then Expression
(P
) = N
3438 Ttyp
:= Etype
(Name
(P
));
3440 -- For indexed component, use subscript subtype
3442 elsif Nkind
(P
) = N_Indexed_Component
then
3449 Atyp
:= Etype
(Prefix
(P
));
3451 if Is_Access_Type
(Atyp
) then
3452 Atyp
:= Designated_Type
(Atyp
);
3454 -- If the prefix is an access to an unconstrained array,
3455 -- perform check unconditionally: it depends on the bounds
3456 -- of an object and we cannot currently recognize whether
3457 -- the test may be redundant.
3459 if not Is_Constrained
(Atyp
) then
3460 Set_Do_Range_Check
(N
, True);
3464 -- Ditto if the prefix is an explicit dereference whose
3465 -- designated type is unconstrained.
3467 elsif Nkind
(Prefix
(P
)) = N_Explicit_Dereference
3468 and then not Is_Constrained
(Atyp
)
3470 Set_Do_Range_Check
(N
, True);
3474 Indx
:= First_Index
(Atyp
);
3475 Subs
:= First
(Expressions
(P
));
3478 Ttyp
:= Etype
(Indx
);
3487 -- For now, ignore all other cases, they are not so interesting
3490 if Debug_Flag_CC
then
3491 w
(" target type not found, flag set");
3494 Set_Do_Range_Check
(N
, True);
3498 -- Evaluate and check the expression
3503 Target_Type
=> Ttyp
,
3509 if Debug_Flag_CC
then
3510 w
("Called Find_Check");
3511 w
("Target_Typ = ", Int
(Ttyp
));
3515 w
(" Check_Num = ", Chk
);
3516 w
(" Ent = ", Int
(Ent
));
3517 Write_Str
(" Ofs = ");
3522 -- If check is not of form to optimize, then set flag and we are done
3525 if Debug_Flag_CC
then
3526 w
(" expression not of optimizable type, flag set");
3529 Set_Do_Range_Check
(N
, True);
3533 -- If check is already performed, then return without setting flag
3536 if Debug_Flag_CC
then
3537 w
("Check suppressed!");
3543 -- Here we will make a new entry for the new check
3545 Set_Do_Range_Check
(N
, True);
3546 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
3547 Saved_Checks
(Num_Saved_Checks
) :=
3552 Target_Type
=> Ttyp
);
3554 if Debug_Flag_CC
then
3555 w
("Make new entry, check number = ", Num_Saved_Checks
);
3556 w
(" Entity = ", Int
(Ent
));
3557 Write_Str
(" Offset = ");
3559 w
(" Check_Type = R");
3560 w
(" Target_Type = ", Int
(Ttyp
));
3564 -- If we get an exception, then something went wrong, probably because
3565 -- of an error in the structure of the tree due to an incorrect program.
3566 -- Or it may be a bug in the optimization circuit. In either case the
3567 -- safest thing is simply to set the check flag unconditionally.
3571 Set_Do_Range_Check
(N
, True);
3573 if Debug_Flag_CC
then
3574 w
(" exception occurred, range flag set");
3578 end Enable_Range_Check
;
3584 procedure Ensure_Valid
(Expr
: Node_Id
; Holes_OK
: Boolean := False) is
3585 Typ
: constant Entity_Id
:= Etype
(Expr
);
3588 -- Ignore call if we are not doing any validity checking
3590 if not Validity_Checks_On
then
3593 -- Ignore call if range checks suppressed on entity in question
3595 elsif Is_Entity_Name
(Expr
)
3596 and then Range_Checks_Suppressed
(Entity
(Expr
))
3600 -- No check required if expression is from the expander, we assume
3601 -- the expander will generate whatever checks are needed. Note that
3602 -- this is not just an optimization, it avoids infinite recursions!
3604 -- Unchecked conversions must be checked, unless they are initialized
3605 -- scalar values, as in a component assignment in an init proc.
3607 -- In addition, we force a check if Force_Validity_Checks is set
3609 elsif not Comes_From_Source
(Expr
)
3610 and then not Force_Validity_Checks
3611 and then (Nkind
(Expr
) /= N_Unchecked_Type_Conversion
3612 or else Kill_Range_Check
(Expr
))
3616 -- No check required if expression is known to have valid value
3618 elsif Expr_Known_Valid
(Expr
) then
3621 -- No check required if checks off
3623 elsif Range_Checks_Suppressed
(Typ
) then
3626 -- Ignore case of enumeration with holes where the flag is set not
3627 -- to worry about holes, since no special validity check is needed
3629 elsif Is_Enumeration_Type
(Typ
)
3630 and then Has_Non_Standard_Rep
(Typ
)
3635 -- No check required on the left-hand side of an assignment
3637 elsif Nkind
(Parent
(Expr
)) = N_Assignment_Statement
3638 and then Expr
= Name
(Parent
(Expr
))
3642 -- An annoying special case. If this is an out parameter of a scalar
3643 -- type, then the value is not going to be accessed, therefore it is
3644 -- inappropriate to do any validity check at the call site.
3647 -- Only need to worry about scalar types
3649 if Is_Scalar_Type
(Typ
) then
3659 -- Find actual argument (which may be a parameter association)
3660 -- and the parent of the actual argument (the call statement)
3665 if Nkind
(P
) = N_Parameter_Association
then
3670 -- Only need to worry if we are argument of a procedure
3671 -- call since functions don't have out parameters. If this
3672 -- is an indirect or dispatching call, get signature from
3673 -- the subprogram type.
3675 if Nkind
(P
) = N_Procedure_Call_Statement
then
3676 L
:= Parameter_Associations
(P
);
3678 if Is_Entity_Name
(Name
(P
)) then
3679 E
:= Entity
(Name
(P
));
3681 pragma Assert
(Nkind
(Name
(P
)) = N_Explicit_Dereference
);
3682 E
:= Etype
(Name
(P
));
3685 -- Only need to worry if there are indeed actuals, and
3686 -- if this could be a procedure call, otherwise we cannot
3687 -- get a match (either we are not an argument, or the
3688 -- mode of the formal is not OUT). This test also filters
3689 -- out the generic case.
3691 if Is_Non_Empty_List
(L
)
3692 and then Is_Subprogram
(E
)
3694 -- This is the loop through parameters, looking to
3695 -- see if there is an OUT parameter for which we are
3698 F
:= First_Formal
(E
);
3701 while Present
(F
) loop
3702 if Ekind
(F
) = E_Out_Parameter
and then A
= N
then
3715 -- If we fall through, a validity check is required. Note that it would
3716 -- not be good to set Do_Range_Check, even in contexts where this is
3717 -- permissible, since this flag causes checking against the target type,
3718 -- not the source type in contexts such as assignments
3720 Insert_Valid_Check
(Expr
);
3723 ----------------------
3724 -- Expr_Known_Valid --
3725 ----------------------
3727 function Expr_Known_Valid
(Expr
: Node_Id
) return Boolean is
3728 Typ
: constant Entity_Id
:= Etype
(Expr
);
3731 -- Non-scalar types are always considered valid, since they never
3732 -- give rise to the issues of erroneous or bounded error behavior
3733 -- that are the concern. In formal reference manual terms the
3734 -- notion of validity only applies to scalar types. Note that
3735 -- even when packed arrays are represented using modular types,
3736 -- they are still arrays semantically, so they are also always
3737 -- valid (in particular, the unused bits can be random rubbish
3738 -- without affecting the validity of the array value).
3740 if not Is_Scalar_Type
(Typ
) or else Is_Packed_Array_Type
(Typ
) then
3743 -- If no validity checking, then everything is considered valid
3745 elsif not Validity_Checks_On
then
3748 -- Floating-point types are considered valid unless floating-point
3749 -- validity checks have been specifically turned on.
3751 elsif Is_Floating_Point_Type
(Typ
)
3752 and then not Validity_Check_Floating_Point
3756 -- If the expression is the value of an object that is known to
3757 -- be valid, then clearly the expression value itself is valid.
3759 elsif Is_Entity_Name
(Expr
)
3760 and then Is_Known_Valid
(Entity
(Expr
))
3764 -- If the type is one for which all values are known valid, then
3765 -- we are sure that the value is valid except in the slightly odd
3766 -- case where the expression is a reference to a variable whose size
3767 -- has been explicitly set to a value greater than the object size.
3769 elsif Is_Known_Valid
(Typ
) then
3770 if Is_Entity_Name
(Expr
)
3771 and then Ekind
(Entity
(Expr
)) = E_Variable
3772 and then Esize
(Entity
(Expr
)) > Esize
(Typ
)
3779 -- Integer and character literals always have valid values, where
3780 -- appropriate these will be range checked in any case.
3782 elsif Nkind
(Expr
) = N_Integer_Literal
3784 Nkind
(Expr
) = N_Character_Literal
3788 -- If we have a type conversion or a qualification of a known valid
3789 -- value, then the result will always be valid.
3791 elsif Nkind
(Expr
) = N_Type_Conversion
3793 Nkind
(Expr
) = N_Qualified_Expression
3795 return Expr_Known_Valid
(Expression
(Expr
));
3797 -- The result of any function call or operator is always considered
3798 -- valid, since we assume the necessary checks are done by the call.
3799 -- For operators on floating-point operations, we must also check
3800 -- when the operation is the right-hand side of an assignment, or
3801 -- is an actual in a call.
3804 Nkind
(Expr
) in N_Binary_Op
or else Nkind
(Expr
) in N_Unary_Op
3806 if Is_Floating_Point_Type
(Typ
)
3807 and then Validity_Check_Floating_Point
3809 (Nkind
(Parent
(Expr
)) = N_Assignment_Statement
3810 or else Nkind
(Parent
(Expr
)) = N_Function_Call
3811 or else Nkind
(Parent
(Expr
)) = N_Parameter_Association
)
3818 elsif Nkind
(Expr
) = N_Function_Call
then
3821 -- For all other cases, we do not know the expression is valid
3826 end Expr_Known_Valid
;
3832 procedure Find_Check
3834 Check_Type
: Character;
3835 Target_Type
: Entity_Id
;
3836 Entry_OK
: out Boolean;
3837 Check_Num
: out Nat
;
3838 Ent
: out Entity_Id
;
3841 function Within_Range_Of
3842 (Target_Type
: Entity_Id
;
3843 Check_Type
: Entity_Id
) return Boolean;
3844 -- Given a requirement for checking a range against Target_Type, and
3845 -- and a range Check_Type against which a check has already been made,
3846 -- determines if the check against check type is sufficient to ensure
3847 -- that no check against Target_Type is required.
3849 ---------------------
3850 -- Within_Range_Of --
3851 ---------------------
3853 function Within_Range_Of
3854 (Target_Type
: Entity_Id
;
3855 Check_Type
: Entity_Id
) return Boolean
3858 if Target_Type
= Check_Type
then
3863 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Type
);
3864 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Type
);
3865 Clo
: constant Node_Id
:= Type_Low_Bound
(Check_Type
);
3866 Chi
: constant Node_Id
:= Type_High_Bound
(Check_Type
);
3870 or else (Compile_Time_Known_Value
(Tlo
)
3872 Compile_Time_Known_Value
(Clo
)
3874 Expr_Value
(Clo
) >= Expr_Value
(Tlo
)))
3877 or else (Compile_Time_Known_Value
(Thi
)
3879 Compile_Time_Known_Value
(Chi
)
3881 Expr_Value
(Chi
) <= Expr_Value
(Clo
)))
3889 end Within_Range_Of
;
3891 -- Start of processing for Find_Check
3894 -- Establish default, to avoid warnings from GCC
3898 -- Case of expression is simple entity reference
3900 if Is_Entity_Name
(Expr
) then
3901 Ent
:= Entity
(Expr
);
3904 -- Case of expression is entity + known constant
3906 elsif Nkind
(Expr
) = N_Op_Add
3907 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
3908 and then Is_Entity_Name
(Left_Opnd
(Expr
))
3910 Ent
:= Entity
(Left_Opnd
(Expr
));
3911 Ofs
:= Expr_Value
(Right_Opnd
(Expr
));
3913 -- Case of expression is entity - known constant
3915 elsif Nkind
(Expr
) = N_Op_Subtract
3916 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
3917 and then Is_Entity_Name
(Left_Opnd
(Expr
))
3919 Ent
:= Entity
(Left_Opnd
(Expr
));
3920 Ofs
:= UI_Negate
(Expr_Value
(Right_Opnd
(Expr
)));
3922 -- Any other expression is not of the right form
3931 -- Come here with expression of appropriate form, check if
3932 -- entity is an appropriate one for our purposes.
3934 if (Ekind
(Ent
) = E_Variable
3936 Ekind
(Ent
) = E_Constant
3938 Ekind
(Ent
) = E_Loop_Parameter
3940 Ekind
(Ent
) = E_In_Parameter
)
3941 and then not Is_Library_Level_Entity
(Ent
)
3949 -- See if there is matching check already
3951 for J
in reverse 1 .. Num_Saved_Checks
loop
3953 SC
: Saved_Check
renames Saved_Checks
(J
);
3956 if SC
.Killed
= False
3957 and then SC
.Entity
= Ent
3958 and then SC
.Offset
= Ofs
3959 and then SC
.Check_Type
= Check_Type
3960 and then Within_Range_Of
(Target_Type
, SC
.Target_Type
)
3968 -- If we fall through entry was not found
3974 ---------------------------------
3975 -- Generate_Discriminant_Check --
3976 ---------------------------------
3978 -- Note: the code for this procedure is derived from the
3979 -- emit_discriminant_check routine a-trans.c v1.659.
3981 procedure Generate_Discriminant_Check
(N
: Node_Id
) is
3982 Loc
: constant Source_Ptr
:= Sloc
(N
);
3983 Pref
: constant Node_Id
:= Prefix
(N
);
3984 Sel
: constant Node_Id
:= Selector_Name
(N
);
3986 Orig_Comp
: constant Entity_Id
:=
3987 Original_Record_Component
(Entity
(Sel
));
3988 -- The original component to be checked
3990 Discr_Fct
: constant Entity_Id
:=
3991 Discriminant_Checking_Func
(Orig_Comp
);
3992 -- The discriminant checking function
3995 -- One discriminant to be checked in the type
3997 Real_Discr
: Entity_Id
;
3998 -- Actual discriminant in the call
4000 Pref_Type
: Entity_Id
;
4001 -- Type of relevant prefix (ignoring private/access stuff)
4004 -- List of arguments for function call
4007 -- Keep track of the formal corresponding to the actual we build
4008 -- for each discriminant, in order to be able to perform the
4009 -- necessary type conversions.
4012 -- Selected component reference for checking function argument
4015 Pref_Type
:= Etype
(Pref
);
4017 -- Force evaluation of the prefix, so that it does not get evaluated
4018 -- twice (once for the check, once for the actual reference). Such a
4019 -- double evaluation is always a potential source of inefficiency,
4020 -- and is functionally incorrect in the volatile case, or when the
4021 -- prefix may have side-effects. An entity or a component of an
4022 -- entity requires no evaluation.
4024 if Is_Entity_Name
(Pref
) then
4025 if Treat_As_Volatile
(Entity
(Pref
)) then
4026 Force_Evaluation
(Pref
, Name_Req
=> True);
4029 elsif Treat_As_Volatile
(Etype
(Pref
)) then
4030 Force_Evaluation
(Pref
, Name_Req
=> True);
4032 elsif Nkind
(Pref
) = N_Selected_Component
4033 and then Is_Entity_Name
(Prefix
(Pref
))
4038 Force_Evaluation
(Pref
, Name_Req
=> True);
4041 -- For a tagged type, use the scope of the original component to
4042 -- obtain the type, because ???
4044 if Is_Tagged_Type
(Scope
(Orig_Comp
)) then
4045 Pref_Type
:= Scope
(Orig_Comp
);
4047 -- For an untagged derived type, use the discriminants of the
4048 -- parent which have been renamed in the derivation, possibly
4049 -- by a one-to-many discriminant constraint.
4050 -- For non-tagged type, initially get the Etype of the prefix
4053 if Is_Derived_Type
(Pref_Type
)
4054 and then Number_Discriminants
(Pref_Type
) /=
4055 Number_Discriminants
(Etype
(Base_Type
(Pref_Type
)))
4057 Pref_Type
:= Etype
(Base_Type
(Pref_Type
));
4061 -- We definitely should have a checking function, This routine should
4062 -- not be called if no discriminant checking function is present.
4064 pragma Assert
(Present
(Discr_Fct
));
4066 -- Create the list of the actual parameters for the call. This list
4067 -- is the list of the discriminant fields of the record expression to
4068 -- be discriminant checked.
4071 Formal
:= First_Formal
(Discr_Fct
);
4072 Discr
:= First_Discriminant
(Pref_Type
);
4073 while Present
(Discr
) loop
4075 -- If we have a corresponding discriminant field, and a parent
4076 -- subtype is present, then we want to use the corresponding
4077 -- discriminant since this is the one with the useful value.
4079 if Present
(Corresponding_Discriminant
(Discr
))
4080 and then Ekind
(Pref_Type
) = E_Record_Type
4081 and then Present
(Parent_Subtype
(Pref_Type
))
4083 Real_Discr
:= Corresponding_Discriminant
(Discr
);
4085 Real_Discr
:= Discr
;
4088 -- Construct the reference to the discriminant
4091 Make_Selected_Component
(Loc
,
4093 Unchecked_Convert_To
(Pref_Type
,
4094 Duplicate_Subexpr
(Pref
)),
4095 Selector_Name
=> New_Occurrence_Of
(Real_Discr
, Loc
));
4097 -- Manually analyze and resolve this selected component. We really
4098 -- want it just as it appears above, and do not want the expander
4099 -- playing discriminal games etc with this reference. Then we
4100 -- append the argument to the list we are gathering.
4102 Set_Etype
(Scomp
, Etype
(Real_Discr
));
4103 Set_Analyzed
(Scomp
, True);
4104 Append_To
(Args
, Convert_To
(Etype
(Formal
), Scomp
));
4106 Next_Formal_With_Extras
(Formal
);
4107 Next_Discriminant
(Discr
);
4110 -- Now build and insert the call
4113 Make_Raise_Constraint_Error
(Loc
,
4115 Make_Function_Call
(Loc
,
4116 Name
=> New_Occurrence_Of
(Discr_Fct
, Loc
),
4117 Parameter_Associations
=> Args
),
4118 Reason
=> CE_Discriminant_Check_Failed
));
4119 end Generate_Discriminant_Check
;
4121 ---------------------------
4122 -- Generate_Index_Checks --
4123 ---------------------------
4125 procedure Generate_Index_Checks
(N
: Node_Id
) is
4126 Loc
: constant Source_Ptr
:= Sloc
(N
);
4127 A
: constant Node_Id
:= Prefix
(N
);
4133 Sub
:= First
(Expressions
(N
));
4135 while Present
(Sub
) loop
4136 if Do_Range_Check
(Sub
) then
4137 Set_Do_Range_Check
(Sub
, False);
4139 -- Force evaluation except for the case of a simple name of
4140 -- a non-volatile entity.
4142 if not Is_Entity_Name
(Sub
)
4143 or else Treat_As_Volatile
(Entity
(Sub
))
4145 Force_Evaluation
(Sub
);
4148 -- Generate a raise of constraint error with the appropriate
4149 -- reason and a condition of the form:
4151 -- Base_Type(Sub) not in array'range (subscript)
4153 -- Note that the reason we generate the conversion to the
4154 -- base type here is that we definitely want the range check
4155 -- to take place, even if it looks like the subtype is OK.
4156 -- Optimization considerations that allow us to omit the
4157 -- check have already been taken into account in the setting
4158 -- of the Do_Range_Check flag earlier on.
4163 Num
:= New_List
(Make_Integer_Literal
(Loc
, Ind
));
4167 Make_Raise_Constraint_Error
(Loc
,
4171 Convert_To
(Base_Type
(Etype
(Sub
)),
4172 Duplicate_Subexpr_Move_Checks
(Sub
)),
4174 Make_Attribute_Reference
(Loc
,
4175 Prefix
=> Duplicate_Subexpr_Move_Checks
(A
),
4176 Attribute_Name
=> Name_Range
,
4177 Expressions
=> Num
)),
4178 Reason
=> CE_Index_Check_Failed
));
4184 end Generate_Index_Checks
;
4186 --------------------------
4187 -- Generate_Range_Check --
4188 --------------------------
4190 procedure Generate_Range_Check
4192 Target_Type
: Entity_Id
;
4193 Reason
: RT_Exception_Code
)
4195 Loc
: constant Source_Ptr
:= Sloc
(N
);
4196 Source_Type
: constant Entity_Id
:= Etype
(N
);
4197 Source_Base_Type
: constant Entity_Id
:= Base_Type
(Source_Type
);
4198 Target_Base_Type
: constant Entity_Id
:= Base_Type
(Target_Type
);
4201 -- First special case, if the source type is already within the
4202 -- range of the target type, then no check is needed (probably we
4203 -- should have stopped Do_Range_Check from being set in the first
4204 -- place, but better late than later in preventing junk code!
4206 -- We do NOT apply this if the source node is a literal, since in
4207 -- this case the literal has already been labeled as having the
4208 -- subtype of the target.
4210 if In_Subrange_Of
(Source_Type
, Target_Type
)
4212 (Nkind
(N
) = N_Integer_Literal
4214 Nkind
(N
) = N_Real_Literal
4216 Nkind
(N
) = N_Character_Literal
4219 and then Ekind
(Entity
(N
)) = E_Enumeration_Literal
))
4224 -- We need a check, so force evaluation of the node, so that it does
4225 -- not get evaluated twice (once for the check, once for the actual
4226 -- reference). Such a double evaluation is always a potential source
4227 -- of inefficiency, and is functionally incorrect in the volatile case.
4229 if not Is_Entity_Name
(N
)
4230 or else Treat_As_Volatile
(Entity
(N
))
4232 Force_Evaluation
(N
);
4235 -- The easiest case is when Source_Base_Type and Target_Base_Type
4236 -- are the same since in this case we can simply do a direct
4237 -- check of the value of N against the bounds of Target_Type.
4239 -- [constraint_error when N not in Target_Type]
4241 -- Note: this is by far the most common case, for example all cases of
4242 -- checks on the RHS of assignments are in this category, but not all
4243 -- cases are like this. Notably conversions can involve two types.
4245 if Source_Base_Type
= Target_Base_Type
then
4247 Make_Raise_Constraint_Error
(Loc
,
4250 Left_Opnd
=> Duplicate_Subexpr
(N
),
4251 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
4254 -- Next test for the case where the target type is within the bounds
4255 -- of the base type of the source type, since in this case we can
4256 -- simply convert these bounds to the base type of T to do the test.
4258 -- [constraint_error when N not in
4259 -- Source_Base_Type (Target_Type'First)
4261 -- Source_Base_Type(Target_Type'Last))]
4263 -- The conversions will always work and need no check
4265 elsif In_Subrange_Of
(Target_Type
, Source_Base_Type
) then
4267 Make_Raise_Constraint_Error
(Loc
,
4270 Left_Opnd
=> Duplicate_Subexpr
(N
),
4275 Convert_To
(Source_Base_Type
,
4276 Make_Attribute_Reference
(Loc
,
4278 New_Occurrence_Of
(Target_Type
, Loc
),
4279 Attribute_Name
=> Name_First
)),
4282 Convert_To
(Source_Base_Type
,
4283 Make_Attribute_Reference
(Loc
,
4285 New_Occurrence_Of
(Target_Type
, Loc
),
4286 Attribute_Name
=> Name_Last
)))),
4289 -- Note that at this stage we now that the Target_Base_Type is
4290 -- not in the range of the Source_Base_Type (since even the
4291 -- Target_Type itself is not in this range). It could still be
4292 -- the case that the Source_Type is in range of the target base
4293 -- type, since we have not checked that case.
4295 -- If that is the case, we can freely convert the source to the
4296 -- target, and then test the target result against the bounds.
4298 elsif In_Subrange_Of
(Source_Type
, Target_Base_Type
) then
4300 -- We make a temporary to hold the value of the converted
4301 -- value (converted to the base type), and then we will
4302 -- do the test against this temporary.
4304 -- Tnn : constant Target_Base_Type := Target_Base_Type (N);
4305 -- [constraint_error when Tnn not in Target_Type]
4307 -- Then the conversion itself is replaced by an occurrence of Tnn
4310 Tnn
: constant Entity_Id
:=
4311 Make_Defining_Identifier
(Loc
,
4312 Chars
=> New_Internal_Name
('T'));
4315 Insert_Actions
(N
, New_List
(
4316 Make_Object_Declaration
(Loc
,
4317 Defining_Identifier
=> Tnn
,
4318 Object_Definition
=>
4319 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4320 Constant_Present
=> True,
4322 Make_Type_Conversion
(Loc
,
4323 Subtype_Mark
=> New_Occurrence_Of
(Target_Base_Type
, Loc
),
4324 Expression
=> Duplicate_Subexpr
(N
))),
4326 Make_Raise_Constraint_Error
(Loc
,
4329 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
4330 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
4332 Reason
=> Reason
)));
4334 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
4337 -- At this stage, we know that we have two scalar types, which are
4338 -- directly convertible, and where neither scalar type has a base
4339 -- range that is in the range of the other scalar type.
4341 -- The only way this can happen is with a signed and unsigned type.
4342 -- So test for these two cases:
4345 -- Case of the source is unsigned and the target is signed
4347 if Is_Unsigned_Type
(Source_Base_Type
)
4348 and then not Is_Unsigned_Type
(Target_Base_Type
)
4350 -- If the source is unsigned and the target is signed, then we
4351 -- know that the source is not shorter than the target (otherwise
4352 -- the source base type would be in the target base type range).
4354 -- In other words, the unsigned type is either the same size
4355 -- as the target, or it is larger. It cannot be smaller.
4358 (Esize
(Source_Base_Type
) >= Esize
(Target_Base_Type
));
4360 -- We only need to check the low bound if the low bound of the
4361 -- target type is non-negative. If the low bound of the target
4362 -- type is negative, then we know that we will fit fine.
4364 -- If the high bound of the target type is negative, then we
4365 -- know we have a constraint error, since we can't possibly
4366 -- have a negative source.
4368 -- With these two checks out of the way, we can do the check
4369 -- using the source type safely
4371 -- This is definitely the most annoying case!
4373 -- [constraint_error
4374 -- when (Target_Type'First >= 0
4376 -- N < Source_Base_Type (Target_Type'First))
4377 -- or else Target_Type'Last < 0
4378 -- or else N > Source_Base_Type (Target_Type'Last)];
4380 -- We turn off all checks since we know that the conversions
4381 -- will work fine, given the guards for negative values.
4384 Make_Raise_Constraint_Error
(Loc
,
4390 Left_Opnd
=> Make_Op_Ge
(Loc
,
4392 Make_Attribute_Reference
(Loc
,
4394 New_Occurrence_Of
(Target_Type
, Loc
),
4395 Attribute_Name
=> Name_First
),
4396 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
4400 Left_Opnd
=> Duplicate_Subexpr
(N
),
4402 Convert_To
(Source_Base_Type
,
4403 Make_Attribute_Reference
(Loc
,
4405 New_Occurrence_Of
(Target_Type
, Loc
),
4406 Attribute_Name
=> Name_First
)))),
4411 Make_Attribute_Reference
(Loc
,
4412 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
4413 Attribute_Name
=> Name_Last
),
4414 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
))),
4418 Left_Opnd
=> Duplicate_Subexpr
(N
),
4420 Convert_To
(Source_Base_Type
,
4421 Make_Attribute_Reference
(Loc
,
4422 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
4423 Attribute_Name
=> Name_Last
)))),
4426 Suppress
=> All_Checks
);
4428 -- Only remaining possibility is that the source is signed and
4429 -- the target is unsigned
4432 pragma Assert
(not Is_Unsigned_Type
(Source_Base_Type
)
4433 and then Is_Unsigned_Type
(Target_Base_Type
));
4435 -- If the source is signed and the target is unsigned, then
4436 -- we know that the target is not shorter than the source
4437 -- (otherwise the target base type would be in the source
4438 -- base type range).
4440 -- In other words, the unsigned type is either the same size
4441 -- as the target, or it is larger. It cannot be smaller.
4443 -- Clearly we have an error if the source value is negative
4444 -- since no unsigned type can have negative values. If the
4445 -- source type is non-negative, then the check can be done
4446 -- using the target type.
4448 -- Tnn : constant Target_Base_Type (N) := Target_Type;
4450 -- [constraint_error
4451 -- when N < 0 or else Tnn not in Target_Type];
4453 -- We turn off all checks for the conversion of N to the
4454 -- target base type, since we generate the explicit check
4455 -- to ensure that the value is non-negative
4458 Tnn
: constant Entity_Id
:=
4459 Make_Defining_Identifier
(Loc
,
4460 Chars
=> New_Internal_Name
('T'));
4463 Insert_Actions
(N
, New_List
(
4464 Make_Object_Declaration
(Loc
,
4465 Defining_Identifier
=> Tnn
,
4466 Object_Definition
=>
4467 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4468 Constant_Present
=> True,
4470 Make_Type_Conversion
(Loc
,
4472 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4473 Expression
=> Duplicate_Subexpr
(N
))),
4475 Make_Raise_Constraint_Error
(Loc
,
4480 Left_Opnd
=> Duplicate_Subexpr
(N
),
4481 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
4485 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
4487 New_Occurrence_Of
(Target_Type
, Loc
))),
4490 Suppress
=> All_Checks
);
4492 -- Set the Etype explicitly, because Insert_Actions may
4493 -- have placed the declaration in the freeze list for an
4494 -- enclosing construct, and thus it is not analyzed yet.
4496 Set_Etype
(Tnn
, Target_Base_Type
);
4497 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
4501 end Generate_Range_Check
;
4503 ---------------------
4504 -- Get_Discriminal --
4505 ---------------------
4507 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
is
4508 Loc
: constant Source_Ptr
:= Sloc
(E
);
4513 -- The entity E is the type of a private component of the protected
4514 -- type, or the type of a renaming of that component within a protected
4515 -- operation of that type.
4519 if Ekind
(Sc
) /= E_Protected_Type
then
4522 if Ekind
(Sc
) /= E_Protected_Type
then
4527 D
:= First_Discriminant
(Sc
);
4530 and then Chars
(D
) /= Chars
(Bound
)
4532 Next_Discriminant
(D
);
4535 return New_Occurrence_Of
(Discriminal
(D
), Loc
);
4536 end Get_Discriminal
;
4542 function Guard_Access
4545 Ck_Node
: Node_Id
) return Node_Id
4548 if Nkind
(Cond
) = N_Or_Else
then
4549 Set_Paren_Count
(Cond
, 1);
4552 if Nkind
(Ck_Node
) = N_Allocator
then
4559 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
4560 Right_Opnd
=> Make_Null
(Loc
)),
4561 Right_Opnd
=> Cond
);
4565 -----------------------------
4566 -- Index_Checks_Suppressed --
4567 -----------------------------
4569 function Index_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4571 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4572 return Is_Check_Suppressed
(E
, Index_Check
);
4574 return Scope_Suppress
(Index_Check
);
4576 end Index_Checks_Suppressed
;
4582 procedure Initialize
is
4584 for J
in Determine_Range_Cache_N
'Range loop
4585 Determine_Range_Cache_N
(J
) := Empty
;
4589 -------------------------
4590 -- Insert_Range_Checks --
4591 -------------------------
4593 procedure Insert_Range_Checks
4594 (Checks
: Check_Result
;
4596 Suppress_Typ
: Entity_Id
;
4597 Static_Sloc
: Source_Ptr
:= No_Location
;
4598 Flag_Node
: Node_Id
:= Empty
;
4599 Do_Before
: Boolean := False)
4601 Internal_Flag_Node
: Node_Id
:= Flag_Node
;
4602 Internal_Static_Sloc
: Source_Ptr
:= Static_Sloc
;
4604 Check_Node
: Node_Id
;
4605 Checks_On
: constant Boolean :=
4606 (not Index_Checks_Suppressed
(Suppress_Typ
))
4608 (not Range_Checks_Suppressed
(Suppress_Typ
));
4611 -- For now we just return if Checks_On is false, however this should
4612 -- be enhanced to check for an always True value in the condition
4613 -- and to generate a compilation warning???
4615 if not Expander_Active
or else not Checks_On
then
4619 if Static_Sloc
= No_Location
then
4620 Internal_Static_Sloc
:= Sloc
(Node
);
4623 if No
(Flag_Node
) then
4624 Internal_Flag_Node
:= Node
;
4627 for J
in 1 .. 2 loop
4628 exit when No
(Checks
(J
));
4630 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
4631 and then Present
(Condition
(Checks
(J
)))
4633 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
4634 Check_Node
:= Checks
(J
);
4635 Mark_Rewrite_Insertion
(Check_Node
);
4638 Insert_Before_And_Analyze
(Node
, Check_Node
);
4640 Insert_After_And_Analyze
(Node
, Check_Node
);
4643 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
4648 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
4649 Reason
=> CE_Range_Check_Failed
);
4650 Mark_Rewrite_Insertion
(Check_Node
);
4653 Insert_Before_And_Analyze
(Node
, Check_Node
);
4655 Insert_After_And_Analyze
(Node
, Check_Node
);
4659 end Insert_Range_Checks
;
4661 ------------------------
4662 -- Insert_Valid_Check --
4663 ------------------------
4665 procedure Insert_Valid_Check
(Expr
: Node_Id
) is
4666 Loc
: constant Source_Ptr
:= Sloc
(Expr
);
4670 -- Do not insert if checks off, or if not checking validity
4672 if Range_Checks_Suppressed
(Etype
(Expr
))
4673 or else (not Validity_Checks_On
)
4678 -- If we have a checked conversion, then validity check applies to
4679 -- the expression inside the conversion, not the result, since if
4680 -- the expression inside is valid, then so is the conversion result.
4683 while Nkind
(Exp
) = N_Type_Conversion
loop
4684 Exp
:= Expression
(Exp
);
4687 -- Insert the validity check. Note that we do this with validity
4688 -- checks turned off, to avoid recursion, we do not want validity
4689 -- checks on the validity checking code itself!
4691 Validity_Checks_On
:= False;
4694 Make_Raise_Constraint_Error
(Loc
,
4698 Make_Attribute_Reference
(Loc
,
4700 Duplicate_Subexpr_No_Checks
(Exp
, Name_Req
=> True),
4701 Attribute_Name
=> Name_Valid
)),
4702 Reason
=> CE_Invalid_Data
),
4703 Suppress
=> All_Checks
);
4704 Validity_Checks_On
:= True;
4705 end Insert_Valid_Check
;
4707 ----------------------------------
4708 -- Install_Null_Excluding_Check --
4709 ----------------------------------
4711 procedure Install_Null_Excluding_Check
(N
: Node_Id
) is
4712 Loc
: constant Source_Ptr
:= Sloc
(N
);
4713 Etyp
: constant Entity_Id
:= Etype
(N
);
4716 pragma Assert
(Is_Access_Type
(Etyp
));
4718 -- Don't need access check if: 1) we are analyzing a generic, 2) it is
4719 -- known to be non-null, or 3) the check was suppressed on the type
4722 or else Access_Checks_Suppressed
(Etyp
)
4726 -- Otherwise install access check
4730 Make_Raise_Constraint_Error
(Loc
,
4733 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(N
),
4734 Right_Opnd
=> Make_Null
(Loc
)),
4735 Reason
=> CE_Access_Check_Failed
));
4737 end Install_Null_Excluding_Check
;
4739 --------------------------
4740 -- Install_Static_Check --
4741 --------------------------
4743 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
) is
4744 Stat
: constant Boolean := Is_Static_Expression
(R_Cno
);
4745 Typ
: constant Entity_Id
:= Etype
(R_Cno
);
4749 Make_Raise_Constraint_Error
(Loc
,
4750 Reason
=> CE_Range_Check_Failed
));
4751 Set_Analyzed
(R_Cno
);
4752 Set_Etype
(R_Cno
, Typ
);
4753 Set_Raises_Constraint_Error
(R_Cno
);
4754 Set_Is_Static_Expression
(R_Cno
, Stat
);
4755 end Install_Static_Check
;
4757 ---------------------
4758 -- Kill_All_Checks --
4759 ---------------------
4761 procedure Kill_All_Checks
is
4763 if Debug_Flag_CC
then
4764 w
("Kill_All_Checks");
4767 -- We reset the number of saved checks to zero, and also modify
4768 -- all stack entries for statement ranges to indicate that the
4769 -- number of checks at each level is now zero.
4771 Num_Saved_Checks
:= 0;
4773 for J
in 1 .. Saved_Checks_TOS
loop
4774 Saved_Checks_Stack
(J
) := 0;
4776 end Kill_All_Checks
;
4782 procedure Kill_Checks
(V
: Entity_Id
) is
4784 if Debug_Flag_CC
then
4785 w
("Kill_Checks for entity", Int
(V
));
4788 for J
in 1 .. Num_Saved_Checks
loop
4789 if Saved_Checks
(J
).Entity
= V
then
4790 if Debug_Flag_CC
then
4791 w
(" Checks killed for saved check ", J
);
4794 Saved_Checks
(J
).Killed
:= True;
4799 ------------------------------
4800 -- Length_Checks_Suppressed --
4801 ------------------------------
4803 function Length_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4805 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4806 return Is_Check_Suppressed
(E
, Length_Check
);
4808 return Scope_Suppress
(Length_Check
);
4810 end Length_Checks_Suppressed
;
4812 --------------------------------
4813 -- Overflow_Checks_Suppressed --
4814 --------------------------------
4816 function Overflow_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4818 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4819 return Is_Check_Suppressed
(E
, Overflow_Check
);
4821 return Scope_Suppress
(Overflow_Check
);
4823 end Overflow_Checks_Suppressed
;
4829 function Range_Check
4831 Target_Typ
: Entity_Id
;
4832 Source_Typ
: Entity_Id
:= Empty
;
4833 Warn_Node
: Node_Id
:= Empty
) return Check_Result
4836 return Selected_Range_Checks
4837 (Ck_Node
, Target_Typ
, Source_Typ
, Warn_Node
);
4840 -----------------------------
4841 -- Range_Checks_Suppressed --
4842 -----------------------------
4844 function Range_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4848 -- Note: for now we always suppress range checks on Vax float types,
4849 -- since Gigi does not know how to generate these checks.
4851 if Vax_Float
(E
) then
4853 elsif Kill_Range_Checks
(E
) then
4855 elsif Checks_May_Be_Suppressed
(E
) then
4856 return Is_Check_Suppressed
(E
, Range_Check
);
4860 return Scope_Suppress
(Range_Check
);
4861 end Range_Checks_Suppressed
;
4867 procedure Remove_Checks
(Expr
: Node_Id
) is
4868 Discard
: Traverse_Result
;
4869 pragma Warnings
(Off
, Discard
);
4871 function Process
(N
: Node_Id
) return Traverse_Result
;
4872 -- Process a single node during the traversal
4874 function Traverse
is new Traverse_Func
(Process
);
4875 -- The traversal function itself
4881 function Process
(N
: Node_Id
) return Traverse_Result
is
4883 if Nkind
(N
) not in N_Subexpr
then
4887 Set_Do_Range_Check
(N
, False);
4891 Discard
:= Traverse
(Left_Opnd
(N
));
4894 when N_Attribute_Reference
=>
4895 Set_Do_Overflow_Check
(N
, False);
4897 when N_Function_Call
=>
4898 Set_Do_Tag_Check
(N
, False);
4901 Set_Do_Overflow_Check
(N
, False);
4905 Set_Do_Division_Check
(N
, False);
4908 Set_Do_Length_Check
(N
, False);
4911 Set_Do_Division_Check
(N
, False);
4914 Set_Do_Length_Check
(N
, False);
4917 Set_Do_Division_Check
(N
, False);
4920 Set_Do_Length_Check
(N
, False);
4927 Discard
:= Traverse
(Left_Opnd
(N
));
4930 when N_Selected_Component
=>
4931 Set_Do_Discriminant_Check
(N
, False);
4933 when N_Type_Conversion
=>
4934 Set_Do_Length_Check
(N
, False);
4935 Set_Do_Tag_Check
(N
, False);
4936 Set_Do_Overflow_Check
(N
, False);
4945 -- Start of processing for Remove_Checks
4948 Discard
:= Traverse
(Expr
);
4951 ----------------------------
4952 -- Selected_Length_Checks --
4953 ----------------------------
4955 function Selected_Length_Checks
4957 Target_Typ
: Entity_Id
;
4958 Source_Typ
: Entity_Id
;
4959 Warn_Node
: Node_Id
) return Check_Result
4961 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
4964 Expr_Actual
: Node_Id
;
4966 Cond
: Node_Id
:= Empty
;
4967 Do_Access
: Boolean := False;
4968 Wnode
: Node_Id
:= Warn_Node
;
4969 Ret_Result
: Check_Result
:= (Empty
, Empty
);
4970 Num_Checks
: Natural := 0;
4972 procedure Add_Check
(N
: Node_Id
);
4973 -- Adds the action given to Ret_Result if N is non-Empty
4975 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
;
4976 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
4977 -- Comments required ???
4979 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean;
4980 -- True for equal literals and for nodes that denote the same constant
4981 -- entity, even if its value is not a static constant. This includes the
4982 -- case of a discriminal reference within an init proc. Removes some
4983 -- obviously superfluous checks.
4985 function Length_E_Cond
4986 (Exptyp
: Entity_Id
;
4988 Indx
: Nat
) return Node_Id
;
4989 -- Returns expression to compute:
4990 -- Typ'Length /= Exptyp'Length
4992 function Length_N_Cond
4995 Indx
: Nat
) return Node_Id
;
4996 -- Returns expression to compute:
4997 -- Typ'Length /= Expr'Length
5003 procedure Add_Check
(N
: Node_Id
) is
5007 -- For now, ignore attempt to place more than 2 checks ???
5009 if Num_Checks
= 2 then
5013 pragma Assert
(Num_Checks
<= 1);
5014 Num_Checks
:= Num_Checks
+ 1;
5015 Ret_Result
(Num_Checks
) := N
;
5023 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
is
5024 Pt
: constant Entity_Id
:= Scope
(Scope
(E
));
5026 E1
: Entity_Id
:= E
;
5029 if Ekind
(Scope
(E
)) = E_Record_Type
5030 and then Has_Discriminants
(Scope
(E
))
5032 N
:= Build_Discriminal_Subtype_Of_Component
(E
);
5035 Insert_Action
(Ck_Node
, N
);
5036 E1
:= Defining_Identifier
(N
);
5040 if Ekind
(E1
) = E_String_Literal_Subtype
then
5042 Make_Integer_Literal
(Loc
,
5043 Intval
=> String_Literal_Length
(E1
));
5045 elsif Ekind
(Pt
) = E_Protected_Type
5046 and then Has_Discriminants
(Pt
)
5047 and then Has_Completion
(Pt
)
5048 and then not Inside_Init_Proc
5051 -- If the type whose length is needed is a private component
5052 -- constrained by a discriminant, we must expand the 'Length
5053 -- attribute into an explicit computation, using the discriminal
5054 -- of the current protected operation. This is because the actual
5055 -- type of the prival is constructed after the protected opera-
5056 -- tion has been fully expanded.
5059 Indx_Type
: Node_Id
;
5062 Do_Expand
: Boolean := False;
5065 Indx_Type
:= First_Index
(E
);
5067 for J
in 1 .. Indx
- 1 loop
5068 Next_Index
(Indx_Type
);
5071 Get_Index_Bounds
(Indx_Type
, Lo
, Hi
);
5073 if Nkind
(Lo
) = N_Identifier
5074 and then Ekind
(Entity
(Lo
)) = E_In_Parameter
5076 Lo
:= Get_Discriminal
(E
, Lo
);
5080 if Nkind
(Hi
) = N_Identifier
5081 and then Ekind
(Entity
(Hi
)) = E_In_Parameter
5083 Hi
:= Get_Discriminal
(E
, Hi
);
5088 if not Is_Entity_Name
(Lo
) then
5089 Lo
:= Duplicate_Subexpr_No_Checks
(Lo
);
5092 if not Is_Entity_Name
(Hi
) then
5093 Lo
:= Duplicate_Subexpr_No_Checks
(Hi
);
5099 Make_Op_Subtract
(Loc
,
5103 Right_Opnd
=> Make_Integer_Literal
(Loc
, 1));
5108 Make_Attribute_Reference
(Loc
,
5109 Attribute_Name
=> Name_Length
,
5111 New_Occurrence_Of
(E1
, Loc
));
5114 Set_Expressions
(N
, New_List
(
5115 Make_Integer_Literal
(Loc
, Indx
)));
5124 Make_Attribute_Reference
(Loc
,
5125 Attribute_Name
=> Name_Length
,
5127 New_Occurrence_Of
(E1
, Loc
));
5130 Set_Expressions
(N
, New_List
(
5131 Make_Integer_Literal
(Loc
, Indx
)));
5143 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5146 Make_Attribute_Reference
(Loc
,
5147 Attribute_Name
=> Name_Length
,
5149 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5150 Expressions
=> New_List
(
5151 Make_Integer_Literal
(Loc
, Indx
)));
5159 function Length_E_Cond
5160 (Exptyp
: Entity_Id
;
5162 Indx
: Nat
) return Node_Id
5167 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
5168 Right_Opnd
=> Get_E_Length
(Exptyp
, Indx
));
5176 function Length_N_Cond
5179 Indx
: Nat
) return Node_Id
5184 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
5185 Right_Opnd
=> Get_N_Length
(Expr
, Indx
));
5189 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean is
5192 (Nkind
(L
) = N_Integer_Literal
5193 and then Nkind
(R
) = N_Integer_Literal
5194 and then Intval
(L
) = Intval
(R
))
5198 and then Ekind
(Entity
(L
)) = E_Constant
5199 and then ((Is_Entity_Name
(R
)
5200 and then Entity
(L
) = Entity
(R
))
5202 (Nkind
(R
) = N_Type_Conversion
5203 and then Is_Entity_Name
(Expression
(R
))
5204 and then Entity
(L
) = Entity
(Expression
(R
)))))
5208 and then Ekind
(Entity
(R
)) = E_Constant
5209 and then Nkind
(L
) = N_Type_Conversion
5210 and then Is_Entity_Name
(Expression
(L
))
5211 and then Entity
(R
) = Entity
(Expression
(L
)))
5215 and then Is_Entity_Name
(R
)
5216 and then Entity
(L
) = Entity
(R
)
5217 and then Ekind
(Entity
(L
)) = E_In_Parameter
5218 and then Inside_Init_Proc
);
5221 -- Start of processing for Selected_Length_Checks
5224 if not Expander_Active
then
5228 if Target_Typ
= Any_Type
5229 or else Target_Typ
= Any_Composite
5230 or else Raises_Constraint_Error
(Ck_Node
)
5239 T_Typ
:= Target_Typ
;
5241 if No
(Source_Typ
) then
5242 S_Typ
:= Etype
(Ck_Node
);
5244 S_Typ
:= Source_Typ
;
5247 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
5251 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
5252 S_Typ
:= Designated_Type
(S_Typ
);
5253 T_Typ
:= Designated_Type
(T_Typ
);
5256 -- A simple optimization
5258 if Nkind
(Ck_Node
) = N_Null
then
5263 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
5264 if Is_Constrained
(T_Typ
) then
5266 -- The checking code to be generated will freeze the
5267 -- corresponding array type. However, we must freeze the
5268 -- type now, so that the freeze node does not appear within
5269 -- the generated condional expression, but ahead of it.
5271 Freeze_Before
(Ck_Node
, T_Typ
);
5273 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
5274 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
5276 if Is_Access_Type
(Exptyp
) then
5277 Exptyp
:= Designated_Type
(Exptyp
);
5280 -- String_Literal case. This needs to be handled specially be-
5281 -- cause no index types are available for string literals. The
5282 -- condition is simply:
5284 -- T_Typ'Length = string-literal-length
5286 if Nkind
(Expr_Actual
) = N_String_Literal
5287 and then Ekind
(Etype
(Expr_Actual
)) = E_String_Literal_Subtype
5291 Left_Opnd
=> Get_E_Length
(T_Typ
, 1),
5293 Make_Integer_Literal
(Loc
,
5295 String_Literal_Length
(Etype
(Expr_Actual
))));
5297 -- General array case. Here we have a usable actual subtype for
5298 -- the expression, and the condition is built from the two types
5301 -- T_Typ'Length /= Exptyp'Length or else
5302 -- T_Typ'Length (2) /= Exptyp'Length (2) or else
5303 -- T_Typ'Length (3) /= Exptyp'Length (3) or else
5306 elsif Is_Constrained
(Exptyp
) then
5308 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
5322 -- At the library level, we need to ensure that the
5323 -- type of the object is elaborated before the check
5324 -- itself is emitted. This is only done if the object
5325 -- is in the current compilation unit, otherwise the
5326 -- type is frozen and elaborated in its unit.
5328 if Is_Itype
(Exptyp
)
5330 Ekind
(Cunit_Entity
(Current_Sem_Unit
)) = E_Package
5332 not In_Package_Body
(Cunit_Entity
(Current_Sem_Unit
))
5333 and then In_Open_Scopes
(Scope
(Exptyp
))
5335 Ref_Node
:= Make_Itype_Reference
(Sloc
(Ck_Node
));
5336 Set_Itype
(Ref_Node
, Exptyp
);
5337 Insert_Action
(Ck_Node
, Ref_Node
);
5340 L_Index
:= First_Index
(T_Typ
);
5341 R_Index
:= First_Index
(Exptyp
);
5343 for Indx
in 1 .. Ndims
loop
5344 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
5346 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
5348 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
5349 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
5351 -- Deal with compile time length check. Note that we
5352 -- skip this in the access case, because the access
5353 -- value may be null, so we cannot know statically.
5356 and then Compile_Time_Known_Value
(L_Low
)
5357 and then Compile_Time_Known_Value
(L_High
)
5358 and then Compile_Time_Known_Value
(R_Low
)
5359 and then Compile_Time_Known_Value
(R_High
)
5361 if Expr_Value
(L_High
) >= Expr_Value
(L_Low
) then
5362 L_Length
:= Expr_Value
(L_High
) -
5363 Expr_Value
(L_Low
) + 1;
5365 L_Length
:= UI_From_Int
(0);
5368 if Expr_Value
(R_High
) >= Expr_Value
(R_Low
) then
5369 R_Length
:= Expr_Value
(R_High
) -
5370 Expr_Value
(R_Low
) + 1;
5372 R_Length
:= UI_From_Int
(0);
5375 if L_Length
> R_Length
then
5377 (Compile_Time_Constraint_Error
5378 (Wnode
, "too few elements for}?", T_Typ
));
5380 elsif L_Length
< R_Length
then
5382 (Compile_Time_Constraint_Error
5383 (Wnode
, "too many elements for}?", T_Typ
));
5386 -- The comparison for an individual index subtype
5387 -- is omitted if the corresponding index subtypes
5388 -- statically match, since the result is known to
5389 -- be true. Note that this test is worth while even
5390 -- though we do static evaluation, because non-static
5391 -- subtypes can statically match.
5394 Subtypes_Statically_Match
5395 (Etype
(L_Index
), Etype
(R_Index
))
5398 (Same_Bounds
(L_Low
, R_Low
)
5399 and then Same_Bounds
(L_High
, R_High
))
5402 (Cond
, Length_E_Cond
(Exptyp
, T_Typ
, Indx
));
5411 -- Handle cases where we do not get a usable actual subtype that
5412 -- is constrained. This happens for example in the function call
5413 -- and explicit dereference cases. In these cases, we have to get
5414 -- the length or range from the expression itself, making sure we
5415 -- do not evaluate it more than once.
5417 -- Here Ck_Node is the original expression, or more properly the
5418 -- result of applying Duplicate_Expr to the original tree,
5419 -- forcing the result to be a name.
5423 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
5426 -- Build the condition for the explicit dereference case
5428 for Indx
in 1 .. Ndims
loop
5430 (Cond
, Length_N_Cond
(Ck_Node
, T_Typ
, Indx
));
5437 -- Construct the test and insert into the tree
5439 if Present
(Cond
) then
5441 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
5445 (Make_Raise_Constraint_Error
(Loc
,
5447 Reason
=> CE_Length_Check_Failed
));
5451 end Selected_Length_Checks
;
5453 ---------------------------
5454 -- Selected_Range_Checks --
5455 ---------------------------
5457 function Selected_Range_Checks
5459 Target_Typ
: Entity_Id
;
5460 Source_Typ
: Entity_Id
;
5461 Warn_Node
: Node_Id
) return Check_Result
5463 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
5466 Expr_Actual
: Node_Id
;
5468 Cond
: Node_Id
:= Empty
;
5469 Do_Access
: Boolean := False;
5470 Wnode
: Node_Id
:= Warn_Node
;
5471 Ret_Result
: Check_Result
:= (Empty
, Empty
);
5472 Num_Checks
: Integer := 0;
5474 procedure Add_Check
(N
: Node_Id
);
5475 -- Adds the action given to Ret_Result if N is non-Empty
5477 function Discrete_Range_Cond
5479 Typ
: Entity_Id
) return Node_Id
;
5480 -- Returns expression to compute:
5481 -- Low_Bound (Expr) < Typ'First
5483 -- High_Bound (Expr) > Typ'Last
5485 function Discrete_Expr_Cond
5487 Typ
: Entity_Id
) return Node_Id
;
5488 -- Returns expression to compute:
5493 function Get_E_First_Or_Last
5496 Nam
: Name_Id
) return Node_Id
;
5497 -- Returns expression to compute:
5498 -- E'First or E'Last
5500 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5501 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5502 -- Returns expression to compute:
5503 -- N'First or N'Last using Duplicate_Subexpr_No_Checks
5505 function Range_E_Cond
5506 (Exptyp
: Entity_Id
;
5510 -- Returns expression to compute:
5511 -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
5513 function Range_Equal_E_Cond
5514 (Exptyp
: Entity_Id
;
5516 Indx
: Nat
) return Node_Id
;
5517 -- Returns expression to compute:
5518 -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
5520 function Range_N_Cond
5523 Indx
: Nat
) return Node_Id
;
5524 -- Return expression to compute:
5525 -- Expr'First < Typ'First or else Expr'Last > Typ'Last
5531 procedure Add_Check
(N
: Node_Id
) is
5535 -- For now, ignore attempt to place more than 2 checks ???
5537 if Num_Checks
= 2 then
5541 pragma Assert
(Num_Checks
<= 1);
5542 Num_Checks
:= Num_Checks
+ 1;
5543 Ret_Result
(Num_Checks
) := N
;
5547 -------------------------
5548 -- Discrete_Expr_Cond --
5549 -------------------------
5551 function Discrete_Expr_Cond
5553 Typ
: Entity_Id
) return Node_Id
5561 Convert_To
(Base_Type
(Typ
),
5562 Duplicate_Subexpr_No_Checks
(Expr
)),
5564 Convert_To
(Base_Type
(Typ
),
5565 Get_E_First_Or_Last
(Typ
, 0, Name_First
))),
5570 Convert_To
(Base_Type
(Typ
),
5571 Duplicate_Subexpr_No_Checks
(Expr
)),
5575 Get_E_First_Or_Last
(Typ
, 0, Name_Last
))));
5576 end Discrete_Expr_Cond
;
5578 -------------------------
5579 -- Discrete_Range_Cond --
5580 -------------------------
5582 function Discrete_Range_Cond
5584 Typ
: Entity_Id
) return Node_Id
5586 LB
: Node_Id
:= Low_Bound
(Expr
);
5587 HB
: Node_Id
:= High_Bound
(Expr
);
5589 Left_Opnd
: Node_Id
;
5590 Right_Opnd
: Node_Id
;
5593 if Nkind
(LB
) = N_Identifier
5594 and then Ekind
(Entity
(LB
)) = E_Discriminant
then
5595 LB
:= New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
5598 if Nkind
(HB
) = N_Identifier
5599 and then Ekind
(Entity
(HB
)) = E_Discriminant
then
5600 HB
:= New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
5607 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(LB
)),
5611 (Base_Type
(Typ
), Get_E_First_Or_Last
(Typ
, 0, Name_First
)));
5613 if Base_Type
(Typ
) = Typ
then
5616 elsif Compile_Time_Known_Value
(High_Bound
(Scalar_Range
(Typ
)))
5618 Compile_Time_Known_Value
(High_Bound
(Scalar_Range
5621 if Is_Floating_Point_Type
(Typ
) then
5622 if Expr_Value_R
(High_Bound
(Scalar_Range
(Typ
))) =
5623 Expr_Value_R
(High_Bound
(Scalar_Range
(Base_Type
(Typ
))))
5629 if Expr_Value
(High_Bound
(Scalar_Range
(Typ
))) =
5630 Expr_Value
(High_Bound
(Scalar_Range
(Base_Type
(Typ
))))
5641 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(HB
)),
5646 Get_E_First_Or_Last
(Typ
, 0, Name_Last
)));
5648 return Make_Or_Else
(Loc
, Left_Opnd
, Right_Opnd
);
5649 end Discrete_Range_Cond
;
5651 -------------------------
5652 -- Get_E_First_Or_Last --
5653 -------------------------
5655 function Get_E_First_Or_Last
5658 Nam
: Name_Id
) return Node_Id
5666 if Is_Array_Type
(E
) then
5667 N
:= First_Index
(E
);
5669 for J
in 2 .. Indx
loop
5674 N
:= Scalar_Range
(E
);
5677 if Nkind
(N
) = N_Subtype_Indication
then
5678 LB
:= Low_Bound
(Range_Expression
(Constraint
(N
)));
5679 HB
:= High_Bound
(Range_Expression
(Constraint
(N
)));
5681 elsif Is_Entity_Name
(N
) then
5682 LB
:= Type_Low_Bound
(Etype
(N
));
5683 HB
:= Type_High_Bound
(Etype
(N
));
5686 LB
:= Low_Bound
(N
);
5687 HB
:= High_Bound
(N
);
5690 if Nam
= Name_First
then
5696 if Nkind
(Bound
) = N_Identifier
5697 and then Ekind
(Entity
(Bound
)) = E_Discriminant
5699 -- If this is a task discriminant, and we are the body, we must
5700 -- retrieve the corresponding body discriminal. This is another
5701 -- consequence of the early creation of discriminals, and the
5702 -- need to generate constraint checks before their declarations
5703 -- are made visible.
5705 if Is_Concurrent_Record_Type
(Scope
(Entity
(Bound
))) then
5707 Tsk
: constant Entity_Id
:=
5708 Corresponding_Concurrent_Type
5709 (Scope
(Entity
(Bound
)));
5713 if In_Open_Scopes
(Tsk
)
5714 and then Has_Completion
(Tsk
)
5716 -- Find discriminant of original task, and use its
5717 -- current discriminal, which is the renaming within
5720 Disc
:= First_Discriminant
(Tsk
);
5721 while Present
(Disc
) loop
5722 if Chars
(Disc
) = Chars
(Entity
(Bound
)) then
5723 Set_Scope
(Discriminal
(Disc
), Tsk
);
5724 return New_Occurrence_Of
(Discriminal
(Disc
), Loc
);
5727 Next_Discriminant
(Disc
);
5730 -- That loop should always succeed in finding a matching
5731 -- entry and returning. Fatal error if not.
5733 raise Program_Error
;
5737 New_Occurrence_Of
(Discriminal
(Entity
(Bound
)), Loc
);
5741 return New_Occurrence_Of
(Discriminal
(Entity
(Bound
)), Loc
);
5744 elsif Nkind
(Bound
) = N_Identifier
5745 and then Ekind
(Entity
(Bound
)) = E_In_Parameter
5746 and then not Inside_Init_Proc
5748 return Get_Discriminal
(E
, Bound
);
5750 elsif Nkind
(Bound
) = N_Integer_Literal
then
5751 return Make_Integer_Literal
(Loc
, Intval
(Bound
));
5753 -- Case of a bound that has been rewritten to an
5754 -- N_Raise_Constraint_Error node because it is an out-of-range
5755 -- value. We may not call Duplicate_Subexpr on this node because
5756 -- an N_Raise_Constraint_Error is not side effect free, and we may
5757 -- not assume that we are in the proper context to remove side
5758 -- effects on it at the point of reference.
5760 elsif Nkind
(Bound
) = N_Raise_Constraint_Error
then
5761 return New_Copy_Tree
(Bound
);
5764 return Duplicate_Subexpr_No_Checks
(Bound
);
5766 end Get_E_First_Or_Last
;
5772 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5775 Make_Attribute_Reference
(Loc
,
5776 Attribute_Name
=> Name_First
,
5778 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5779 Expressions
=> New_List
(
5780 Make_Integer_Literal
(Loc
, Indx
)));
5787 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5790 Make_Attribute_Reference
(Loc
,
5791 Attribute_Name
=> Name_Last
,
5793 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5794 Expressions
=> New_List
(
5795 Make_Integer_Literal
(Loc
, Indx
)));
5802 function Range_E_Cond
5803 (Exptyp
: Entity_Id
;
5805 Indx
: Nat
) return Node_Id
5812 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_First
),
5813 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5817 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_Last
),
5818 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5822 ------------------------
5823 -- Range_Equal_E_Cond --
5824 ------------------------
5826 function Range_Equal_E_Cond
5827 (Exptyp
: Entity_Id
;
5829 Indx
: Nat
) return Node_Id
5836 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_First
),
5837 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5840 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_Last
),
5841 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5842 end Range_Equal_E_Cond
;
5848 function Range_N_Cond
5851 Indx
: Nat
) return Node_Id
5858 Left_Opnd
=> Get_N_First
(Expr
, Indx
),
5859 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5863 Left_Opnd
=> Get_N_Last
(Expr
, Indx
),
5864 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5867 -- Start of processing for Selected_Range_Checks
5870 if not Expander_Active
then
5874 if Target_Typ
= Any_Type
5875 or else Target_Typ
= Any_Composite
5876 or else Raises_Constraint_Error
(Ck_Node
)
5885 T_Typ
:= Target_Typ
;
5887 if No
(Source_Typ
) then
5888 S_Typ
:= Etype
(Ck_Node
);
5890 S_Typ
:= Source_Typ
;
5893 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
5897 -- The order of evaluating T_Typ before S_Typ seems to be critical
5898 -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
5899 -- in, and since Node can be an N_Range node, it might be invalid.
5900 -- Should there be an assert check somewhere for taking the Etype of
5901 -- an N_Range node ???
5903 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
5904 S_Typ
:= Designated_Type
(S_Typ
);
5905 T_Typ
:= Designated_Type
(T_Typ
);
5908 -- A simple optimization
5910 if Nkind
(Ck_Node
) = N_Null
then
5915 -- For an N_Range Node, check for a null range and then if not
5916 -- null generate a range check action.
5918 if Nkind
(Ck_Node
) = N_Range
then
5920 -- There's no point in checking a range against itself
5922 if Ck_Node
= Scalar_Range
(T_Typ
) then
5927 T_LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
5928 T_HB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
5929 LB
: constant Node_Id
:= Low_Bound
(Ck_Node
);
5930 HB
: constant Node_Id
:= High_Bound
(Ck_Node
);
5931 Null_Range
: Boolean;
5933 Out_Of_Range_L
: Boolean;
5934 Out_Of_Range_H
: Boolean;
5937 -- Check for case where everything is static and we can
5938 -- do the check at compile time. This is skipped if we
5939 -- have an access type, since the access value may be null.
5941 -- ??? This code can be improved since you only need to know
5942 -- that the two respective bounds (LB & T_LB or HB & T_HB)
5943 -- are known at compile time to emit pertinent messages.
5945 if Compile_Time_Known_Value
(LB
)
5946 and then Compile_Time_Known_Value
(HB
)
5947 and then Compile_Time_Known_Value
(T_LB
)
5948 and then Compile_Time_Known_Value
(T_HB
)
5949 and then not Do_Access
5951 -- Floating-point case
5953 if Is_Floating_Point_Type
(S_Typ
) then
5954 Null_Range
:= Expr_Value_R
(HB
) < Expr_Value_R
(LB
);
5956 (Expr_Value_R
(LB
) < Expr_Value_R
(T_LB
))
5958 (Expr_Value_R
(LB
) > Expr_Value_R
(T_HB
));
5961 (Expr_Value_R
(HB
) > Expr_Value_R
(T_HB
))
5963 (Expr_Value_R
(HB
) < Expr_Value_R
(T_LB
));
5965 -- Fixed or discrete type case
5968 Null_Range
:= Expr_Value
(HB
) < Expr_Value
(LB
);
5970 (Expr_Value
(LB
) < Expr_Value
(T_LB
))
5972 (Expr_Value
(LB
) > Expr_Value
(T_HB
));
5975 (Expr_Value
(HB
) > Expr_Value
(T_HB
))
5977 (Expr_Value
(HB
) < Expr_Value
(T_LB
));
5980 if not Null_Range
then
5981 if Out_Of_Range_L
then
5982 if No
(Warn_Node
) then
5984 (Compile_Time_Constraint_Error
5985 (Low_Bound
(Ck_Node
),
5986 "static value out of range of}?", T_Typ
));
5990 (Compile_Time_Constraint_Error
5992 "static range out of bounds of}?", T_Typ
));
5996 if Out_Of_Range_H
then
5997 if No
(Warn_Node
) then
5999 (Compile_Time_Constraint_Error
6000 (High_Bound
(Ck_Node
),
6001 "static value out of range of}?", T_Typ
));
6005 (Compile_Time_Constraint_Error
6007 "static range out of bounds of}?", T_Typ
));
6015 LB
: Node_Id
:= Low_Bound
(Ck_Node
);
6016 HB
: Node_Id
:= High_Bound
(Ck_Node
);
6020 -- If either bound is a discriminant and we are within
6021 -- the record declaration, it is a use of the discriminant
6022 -- in a constraint of a component, and nothing can be
6023 -- checked here. The check will be emitted within the
6024 -- init proc. Before then, the discriminal has no real
6027 if Nkind
(LB
) = N_Identifier
6028 and then Ekind
(Entity
(LB
)) = E_Discriminant
6030 if Current_Scope
= Scope
(Entity
(LB
)) then
6034 New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
6038 if Nkind
(HB
) = N_Identifier
6039 and then Ekind
(Entity
(HB
)) = E_Discriminant
6041 if Current_Scope
= Scope
(Entity
(HB
)) then
6045 New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
6049 Cond
:= Discrete_Range_Cond
(Ck_Node
, T_Typ
);
6050 Set_Paren_Count
(Cond
, 1);
6056 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(HB
),
6057 Right_Opnd
=> Duplicate_Subexpr_No_Checks
(LB
)),
6058 Right_Opnd
=> Cond
);
6064 elsif Is_Scalar_Type
(S_Typ
) then
6066 -- This somewhat duplicates what Apply_Scalar_Range_Check does,
6067 -- except the above simply sets a flag in the node and lets
6068 -- gigi generate the check base on the Etype of the expression.
6069 -- Sometimes, however we want to do a dynamic check against an
6070 -- arbitrary target type, so we do that here.
6072 if Ekind
(Base_Type
(S_Typ
)) /= Ekind
(Base_Type
(T_Typ
)) then
6073 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6075 -- For literals, we can tell if the constraint error will be
6076 -- raised at compile time, so we never need a dynamic check, but
6077 -- if the exception will be raised, then post the usual warning,
6078 -- and replace the literal with a raise constraint error
6079 -- expression. As usual, skip this for access types
6081 elsif Compile_Time_Known_Value
(Ck_Node
)
6082 and then not Do_Access
6085 LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
6086 UB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
6088 Out_Of_Range
: Boolean;
6089 Static_Bounds
: constant Boolean :=
6090 Compile_Time_Known_Value
(LB
)
6091 and Compile_Time_Known_Value
(UB
);
6094 -- Following range tests should use Sem_Eval routine ???
6096 if Static_Bounds
then
6097 if Is_Floating_Point_Type
(S_Typ
) then
6099 (Expr_Value_R
(Ck_Node
) < Expr_Value_R
(LB
))
6101 (Expr_Value_R
(Ck_Node
) > Expr_Value_R
(UB
));
6103 else -- fixed or discrete type
6105 Expr_Value
(Ck_Node
) < Expr_Value
(LB
)
6107 Expr_Value
(Ck_Node
) > Expr_Value
(UB
);
6110 -- Bounds of the type are static and the literal is
6111 -- out of range so make a warning message.
6113 if Out_Of_Range
then
6114 if No
(Warn_Node
) then
6116 (Compile_Time_Constraint_Error
6118 "static value out of range of}?", T_Typ
));
6122 (Compile_Time_Constraint_Error
6124 "static value out of range of}?", T_Typ
));
6129 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6133 -- Here for the case of a non-static expression, we need a runtime
6134 -- check unless the source type range is guaranteed to be in the
6135 -- range of the target type.
6138 if not In_Subrange_Of
(S_Typ
, T_Typ
) then
6139 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6144 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
6145 if Is_Constrained
(T_Typ
) then
6147 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
6148 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
6150 if Is_Access_Type
(Exptyp
) then
6151 Exptyp
:= Designated_Type
(Exptyp
);
6154 -- String_Literal case. This needs to be handled specially be-
6155 -- cause no index types are available for string literals. The
6156 -- condition is simply:
6158 -- T_Typ'Length = string-literal-length
6160 if Nkind
(Expr_Actual
) = N_String_Literal
then
6163 -- General array case. Here we have a usable actual subtype for
6164 -- the expression, and the condition is built from the two types
6166 -- T_Typ'First < Exptyp'First or else
6167 -- T_Typ'Last > Exptyp'Last or else
6168 -- T_Typ'First(1) < Exptyp'First(1) or else
6169 -- T_Typ'Last(1) > Exptyp'Last(1) or else
6172 elsif Is_Constrained
(Exptyp
) then
6174 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
6184 L_Index
:= First_Index
(T_Typ
);
6185 R_Index
:= First_Index
(Exptyp
);
6187 for Indx
in 1 .. Ndims
loop
6188 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
6190 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
6192 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
6193 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
6195 -- Deal with compile time length check. Note that we
6196 -- skip this in the access case, because the access
6197 -- value may be null, so we cannot know statically.
6200 Subtypes_Statically_Match
6201 (Etype
(L_Index
), Etype
(R_Index
))
6203 -- If the target type is constrained then we
6204 -- have to check for exact equality of bounds
6205 -- (required for qualified expressions).
6207 if Is_Constrained
(T_Typ
) then
6210 Range_Equal_E_Cond
(Exptyp
, T_Typ
, Indx
));
6214 (Cond
, Range_E_Cond
(Exptyp
, T_Typ
, Indx
));
6225 -- Handle cases where we do not get a usable actual subtype that
6226 -- is constrained. This happens for example in the function call
6227 -- and explicit dereference cases. In these cases, we have to get
6228 -- the length or range from the expression itself, making sure we
6229 -- do not evaluate it more than once.
6231 -- Here Ck_Node is the original expression, or more properly the
6232 -- result of applying Duplicate_Expr to the original tree,
6233 -- forcing the result to be a name.
6237 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
6240 -- Build the condition for the explicit dereference case
6242 for Indx
in 1 .. Ndims
loop
6244 (Cond
, Range_N_Cond
(Ck_Node
, T_Typ
, Indx
));
6251 -- Generate an Action to check that the bounds of the
6252 -- source value are within the constraints imposed by the
6253 -- target type for a conversion to an unconstrained type.
6256 if Nkind
(Parent
(Ck_Node
)) = N_Type_Conversion
then
6258 Opnd_Index
: Node_Id
;
6259 Targ_Index
: Node_Id
;
6263 := First_Index
(Get_Actual_Subtype
(Ck_Node
));
6264 Targ_Index
:= First_Index
(T_Typ
);
6266 while Opnd_Index
/= Empty
loop
6267 if Nkind
(Opnd_Index
) = N_Range
then
6269 (Low_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6272 (High_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6276 -- If null range, no check needed
6279 Compile_Time_Known_Value
(High_Bound
(Opnd_Index
))
6281 Compile_Time_Known_Value
(Low_Bound
(Opnd_Index
))
6283 Expr_Value
(High_Bound
(Opnd_Index
)) <
6284 Expr_Value
(Low_Bound
(Opnd_Index
))
6288 elsif Is_Out_Of_Range
6289 (Low_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6292 (High_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6295 (Compile_Time_Constraint_Error
6296 (Wnode
, "value out of range of}?", T_Typ
));
6302 (Opnd_Index
, Etype
(Targ_Index
)));
6306 Next_Index
(Opnd_Index
);
6307 Next_Index
(Targ_Index
);
6314 -- Construct the test and insert into the tree
6316 if Present
(Cond
) then
6318 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
6322 (Make_Raise_Constraint_Error
(Loc
,
6324 Reason
=> CE_Range_Check_Failed
));
6328 end Selected_Range_Checks
;
6330 -------------------------------
6331 -- Storage_Checks_Suppressed --
6332 -------------------------------
6334 function Storage_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6336 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
6337 return Is_Check_Suppressed
(E
, Storage_Check
);
6339 return Scope_Suppress
(Storage_Check
);
6341 end Storage_Checks_Suppressed
;
6343 ---------------------------
6344 -- Tag_Checks_Suppressed --
6345 ---------------------------
6347 function Tag_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6350 if Kill_Tag_Checks
(E
) then
6352 elsif Checks_May_Be_Suppressed
(E
) then
6353 return Is_Check_Suppressed
(E
, Tag_Check
);
6357 return Scope_Suppress
(Tag_Check
);
6358 end Tag_Checks_Suppressed
;