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, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, 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_Pakd
; use Exp_Pakd
;
33 with Exp_Util
; use Exp_Util
;
34 with Elists
; use Elists
;
35 with Eval_Fat
; use Eval_Fat
;
36 with Freeze
; use Freeze
;
38 with Nlists
; use Nlists
;
39 with Nmake
; use Nmake
;
41 with Output
; use Output
;
42 with Restrict
; use Restrict
;
43 with Rident
; use Rident
;
44 with Rtsfind
; use Rtsfind
;
46 with Sem_Eval
; use Sem_Eval
;
47 with Sem_Ch3
; use Sem_Ch3
;
48 with Sem_Ch8
; use Sem_Ch8
;
49 with Sem_Res
; use Sem_Res
;
50 with Sem_Util
; use Sem_Util
;
51 with Sem_Warn
; use Sem_Warn
;
52 with Sinfo
; use Sinfo
;
53 with Sinput
; use Sinput
;
54 with Snames
; use Snames
;
55 with Sprint
; use Sprint
;
56 with Stand
; use Stand
;
57 with Targparm
; use Targparm
;
58 with Tbuild
; use Tbuild
;
59 with Ttypes
; use Ttypes
;
60 with Urealp
; use Urealp
;
61 with Validsw
; use Validsw
;
63 package body Checks
is
65 -- General note: many of these routines are concerned with generating
66 -- checking code to make sure that constraint error is raised at runtime.
67 -- Clearly this code is only needed if the expander is active, since
68 -- otherwise we will not be generating code or going into the runtime
71 -- We therefore disconnect most of these checks if the expander is
72 -- inactive. This has the additional benefit that we do not need to
73 -- worry about the tree being messed up by previous errors (since errors
74 -- turn off expansion anyway).
76 -- There are a few exceptions to the above rule. For instance routines
77 -- such as Apply_Scalar_Range_Check that do not insert any code can be
78 -- safely called even when the Expander is inactive (but Errors_Detected
79 -- is 0). The benefit of executing this code when expansion is off, is
80 -- the ability to emit constraint error warning for static expressions
81 -- even when we are not generating code.
83 -------------------------------------
84 -- Suppression of Redundant Checks --
85 -------------------------------------
87 -- This unit implements a limited circuit for removal of redundant
88 -- checks. The processing is based on a tracing of simple sequential
89 -- flow. For any sequence of statements, we save expressions that are
90 -- marked to be checked, and then if the same expression appears later
91 -- with the same check, then under certain circumstances, the second
92 -- check can be suppressed.
94 -- Basically, we can suppress the check if we know for certain that
95 -- the previous expression has been elaborated (together with its
96 -- check), and we know that the exception frame is the same, and that
97 -- nothing has happened to change the result of the exception.
99 -- Let us examine each of these three conditions in turn to describe
100 -- how we ensure that this condition is met.
102 -- First, we need to know for certain that the previous expression has
103 -- been executed. This is done principly by the mechanism of calling
104 -- Conditional_Statements_Begin at the start of any statement sequence
105 -- and Conditional_Statements_End at the end. The End call causes all
106 -- checks remembered since the Begin call to be discarded. This does
107 -- miss a few cases, notably the case of a nested BEGIN-END block with
108 -- no exception handlers. But the important thing is to be conservative.
109 -- The other protection is that all checks are discarded if a label
110 -- is encountered, since then the assumption of sequential execution
111 -- is violated, and we don't know enough about the flow.
113 -- Second, we need to know that the exception frame is the same. We
114 -- do this by killing all remembered checks when we enter a new frame.
115 -- Again, that's over-conservative, but generally the cases we can help
116 -- with are pretty local anyway (like the body of a loop for example).
118 -- Third, we must be sure to forget any checks which are no longer valid.
119 -- This is done by two mechanisms, first the Kill_Checks_Variable call is
120 -- used to note any changes to local variables. We only attempt to deal
121 -- with checks involving local variables, so we do not need to worry
122 -- about global variables. Second, a call to any non-global procedure
123 -- causes us to abandon all stored checks, since such a all may affect
124 -- the values of any local variables.
126 -- The following define the data structures used to deal with remembering
127 -- checks so that redundant checks can be eliminated as described above.
129 -- Right now, the only expressions that we deal with are of the form of
130 -- simple local objects (either declared locally, or IN parameters) or
131 -- such objects plus/minus a compile time known constant. We can do
132 -- more later on if it seems worthwhile, but this catches many simple
133 -- cases in practice.
135 -- The following record type reflects a single saved check. An entry
136 -- is made in the stack of saved checks if and only if the expression
137 -- has been elaborated with the indicated checks.
139 type Saved_Check
is record
141 -- Set True if entry is killed by Kill_Checks
144 -- The entity involved in the expression that is checked
147 -- A compile time value indicating the result of adding or
148 -- subtracting a compile time value. This value is to be
149 -- added to the value of the Entity. A value of zero is
150 -- used for the case of a simple entity reference.
152 Check_Type
: Character;
153 -- This is set to 'R' for a range check (in which case Target_Type
154 -- is set to the target type for the range check) or to 'O' for an
155 -- overflow check (in which case Target_Type is set to Empty).
157 Target_Type
: Entity_Id
;
158 -- Used only if Do_Range_Check is set. Records the target type for
159 -- the check. We need this, because a check is a duplicate only if
160 -- it has a the same target type (or more accurately one with a
161 -- range that is smaller or equal to the stored target type of a
165 -- The following table keeps track of saved checks. Rather than use an
166 -- extensible table. We just use a table of fixed size, and we discard
167 -- any saved checks that do not fit. That's very unlikely to happen and
168 -- this is only an optimization in any case.
170 Saved_Checks
: array (Int
range 1 .. 200) of Saved_Check
;
171 -- Array of saved checks
173 Num_Saved_Checks
: Nat
:= 0;
174 -- Number of saved checks
176 -- The following stack keeps track of statement ranges. It is treated
177 -- as a stack. When Conditional_Statements_Begin is called, an entry
178 -- is pushed onto this stack containing the value of Num_Saved_Checks
179 -- at the time of the call. Then when Conditional_Statements_End is
180 -- called, this value is popped off and used to reset Num_Saved_Checks.
182 -- Note: again, this is a fixed length stack with a size that should
183 -- always be fine. If the value of the stack pointer goes above the
184 -- limit, then we just forget all saved checks.
186 Saved_Checks_Stack
: array (Int
range 1 .. 100) of Nat
;
187 Saved_Checks_TOS
: Nat
:= 0;
189 -----------------------
190 -- Local Subprograms --
191 -----------------------
193 procedure Apply_Float_Conversion_Check
195 Target_Typ
: Entity_Id
);
196 -- The checks on a conversion from a floating-point type to an integer
197 -- type are delicate. They have to be performed before conversion, they
198 -- have to raise an exception when the operand is a NaN, and rounding must
199 -- be taken into account to determine the safe bounds of the operand.
201 procedure Apply_Selected_Length_Checks
203 Target_Typ
: Entity_Id
;
204 Source_Typ
: Entity_Id
;
205 Do_Static
: Boolean);
206 -- This is the subprogram that does all the work for Apply_Length_Check
207 -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as
208 -- described for the above routines. The Do_Static flag indicates that
209 -- only a static check is to be done.
211 procedure Apply_Selected_Range_Checks
213 Target_Typ
: Entity_Id
;
214 Source_Typ
: Entity_Id
;
215 Do_Static
: Boolean);
216 -- This is the subprogram that does all the work for Apply_Range_Check.
217 -- Expr, Target_Typ and Source_Typ are as described for the above
218 -- routine. The Do_Static flag indicates that only a static check is
223 Check_Type
: Character;
224 Target_Type
: Entity_Id
;
225 Entry_OK
: out Boolean;
229 -- This routine is used by Enable_Range_Check and Enable_Overflow_Check
230 -- to see if a check is of the form for optimization, and if so, to see
231 -- if it has already been performed. Expr is the expression to check,
232 -- and Check_Type is 'R' for a range check, 'O' for an overflow check.
233 -- Target_Type is the target type for a range check, and Empty for an
234 -- overflow check. If the entry is not of the form for optimization,
235 -- then Entry_OK is set to False, and the remaining out parameters
236 -- are undefined. If the entry is OK, then Ent/Ofs are set to the
237 -- entity and offset from the expression. Check_Num is the number of
238 -- a matching saved entry in Saved_Checks, or zero if no such entry
241 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
;
242 -- If a discriminal is used in constraining a prival, Return reference
243 -- to the discriminal of the protected body (which renames the parameter
244 -- of the enclosing protected operation). This clumsy transformation is
245 -- needed because privals are created too late and their actual subtypes
246 -- are not available when analysing the bodies of the protected operations.
247 -- To be cleaned up???
249 function Guard_Access
252 Ck_Node
: Node_Id
) return Node_Id
;
253 -- In the access type case, guard the test with a test to ensure
254 -- that the access value is non-null, since the checks do not
255 -- not apply to null access values.
257 procedure Install_Null_Excluding_Check
(N
: Node_Id
);
258 -- Determines whether an access node requires a runtime access check and
259 -- if so inserts the appropriate run-time check
261 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
);
262 -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the
263 -- Constraint_Error node.
265 function Selected_Length_Checks
267 Target_Typ
: Entity_Id
;
268 Source_Typ
: Entity_Id
;
269 Warn_Node
: Node_Id
) return Check_Result
;
270 -- Like Apply_Selected_Length_Checks, except it doesn't modify
271 -- anything, just returns a list of nodes as described in the spec of
272 -- this package for the Range_Check function.
274 function Selected_Range_Checks
276 Target_Typ
: Entity_Id
;
277 Source_Typ
: Entity_Id
;
278 Warn_Node
: Node_Id
) return Check_Result
;
279 -- Like Apply_Selected_Range_Checks, except it doesn't modify anything,
280 -- just returns a list of nodes as described in the spec of this package
281 -- for the Range_Check function.
283 ------------------------------
284 -- Access_Checks_Suppressed --
285 ------------------------------
287 function Access_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
289 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
290 return Is_Check_Suppressed
(E
, Access_Check
);
292 return Scope_Suppress
(Access_Check
);
294 end Access_Checks_Suppressed
;
296 -------------------------------------
297 -- Accessibility_Checks_Suppressed --
298 -------------------------------------
300 function Accessibility_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
302 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
303 return Is_Check_Suppressed
(E
, Accessibility_Check
);
305 return Scope_Suppress
(Accessibility_Check
);
307 end Accessibility_Checks_Suppressed
;
309 -------------------------
310 -- Append_Range_Checks --
311 -------------------------
313 procedure Append_Range_Checks
314 (Checks
: Check_Result
;
316 Suppress_Typ
: Entity_Id
;
317 Static_Sloc
: Source_Ptr
;
320 Internal_Flag_Node
: constant Node_Id
:= Flag_Node
;
321 Internal_Static_Sloc
: constant Source_Ptr
:= Static_Sloc
;
323 Checks_On
: constant Boolean :=
324 (not Index_Checks_Suppressed
(Suppress_Typ
))
326 (not Range_Checks_Suppressed
(Suppress_Typ
));
329 -- For now we just return if Checks_On is false, however this should
330 -- be enhanced to check for an always True value in the condition
331 -- and to generate a compilation warning???
333 if not Checks_On
then
338 exit when No
(Checks
(J
));
340 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
341 and then Present
(Condition
(Checks
(J
)))
343 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
344 Append_To
(Stmts
, Checks
(J
));
345 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
351 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
352 Reason
=> CE_Range_Check_Failed
));
355 end Append_Range_Checks
;
357 ------------------------
358 -- Apply_Access_Check --
359 ------------------------
361 procedure Apply_Access_Check
(N
: Node_Id
) is
362 P
: constant Node_Id
:= Prefix
(N
);
365 if Inside_A_Generic
then
369 if Is_Entity_Name
(P
) then
370 Check_Unset_Reference
(P
);
373 -- We do not need access checks if prefix is known to be non-null
375 if Known_Non_Null
(P
) then
378 -- We do not need access checks if they are suppressed on the type
380 elsif Access_Checks_Suppressed
(Etype
(P
)) then
383 -- We do not need checks if we are not generating code (i.e. the
384 -- expander is not active). This is not just an optimization, there
385 -- are cases (e.g. with pragma Debug) where generating the checks
386 -- can cause real trouble).
388 elsif not Expander_Active
then
392 -- Case where P is an entity name
394 if Is_Entity_Name
(P
) then
396 Ent
: constant Entity_Id
:= Entity
(P
);
399 if Access_Checks_Suppressed
(Ent
) then
403 -- Otherwise we are going to generate an access check, and
404 -- are we have done it, the entity will now be known non null
405 -- But we have to check for safe sequential semantics here!
407 if Safe_To_Capture_Value
(N
, Ent
) then
408 Set_Is_Known_Non_Null
(Ent
);
413 -- Access check is required
415 Install_Null_Excluding_Check
(P
);
416 end Apply_Access_Check
;
418 -------------------------------
419 -- Apply_Accessibility_Check --
420 -------------------------------
422 procedure Apply_Accessibility_Check
(N
: Node_Id
; Typ
: Entity_Id
) is
423 Loc
: constant Source_Ptr
:= Sloc
(N
);
424 Param_Ent
: constant Entity_Id
:= Param_Entity
(N
);
425 Param_Level
: Node_Id
;
426 Type_Level
: Node_Id
;
429 if Inside_A_Generic
then
432 -- Only apply the run-time check if the access parameter
433 -- has an associated extra access level parameter and
434 -- when the level of the type is less deep than the level
435 -- of the access parameter.
437 elsif Present
(Param_Ent
)
438 and then Present
(Extra_Accessibility
(Param_Ent
))
439 and then UI_Gt
(Object_Access_Level
(N
),
440 Type_Access_Level
(Typ
))
441 and then not Accessibility_Checks_Suppressed
(Param_Ent
)
442 and then not Accessibility_Checks_Suppressed
(Typ
)
445 New_Occurrence_Of
(Extra_Accessibility
(Param_Ent
), Loc
);
448 Make_Integer_Literal
(Loc
, Type_Access_Level
(Typ
));
450 -- Raise Program_Error if the accessibility level of the
451 -- the access parameter is deeper than the level of the
452 -- target access type.
455 Make_Raise_Program_Error
(Loc
,
458 Left_Opnd
=> Param_Level
,
459 Right_Opnd
=> Type_Level
),
460 Reason
=> PE_Accessibility_Check_Failed
));
462 Analyze_And_Resolve
(N
);
464 end Apply_Accessibility_Check
;
466 ---------------------------
467 -- Apply_Alignment_Check --
468 ---------------------------
470 procedure Apply_Alignment_Check
(E
: Entity_Id
; N
: Node_Id
) is
471 AC
: constant Node_Id
:= Address_Clause
(E
);
472 Typ
: constant Entity_Id
:= Etype
(E
);
476 Alignment_Required
: constant Boolean := Maximum_Alignment
> 1;
477 -- Constant to show whether target requires alignment checks
480 -- See if check needed. Note that we never need a check if the
481 -- maximum alignment is one, since the check will always succeed
484 or else not Check_Address_Alignment
(AC
)
485 or else not Alignment_Required
491 Expr
:= Expression
(AC
);
493 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
then
494 Expr
:= Expression
(Expr
);
496 elsif Nkind
(Expr
) = N_Function_Call
497 and then Is_Entity_Name
(Name
(Expr
))
498 and then Is_RTE
(Entity
(Name
(Expr
)), RE_To_Address
)
500 Expr
:= First
(Parameter_Associations
(Expr
));
502 if Nkind
(Expr
) = N_Parameter_Association
then
503 Expr
:= Explicit_Actual_Parameter
(Expr
);
507 -- Here Expr is the address value. See if we know that the
508 -- value is unacceptable at compile time.
510 if Compile_Time_Known_Value
(Expr
)
511 and then (Known_Alignment
(E
) or else Known_Alignment
(Typ
))
514 AL
: Uint
:= Alignment
(Typ
);
517 -- The object alignment might be more restrictive than the
520 if Known_Alignment
(E
) then
524 if Expr_Value
(Expr
) mod AL
/= 0 then
526 Make_Raise_Program_Error
(Loc
,
527 Reason
=> PE_Misaligned_Address_Value
));
529 ("?specified address for& not " &
530 "consistent with alignment ('R'M 13.3(27))", Expr
, E
);
534 -- Here we do not know if the value is acceptable, generate
535 -- code to raise PE if alignment is inappropriate.
538 -- Skip generation of this code if we don't want elab code
540 if not Restriction_Active
(No_Elaboration_Code
) then
541 Insert_After_And_Analyze
(N
,
542 Make_Raise_Program_Error
(Loc
,
549 (RTE
(RE_Integer_Address
),
550 Duplicate_Subexpr_No_Checks
(Expr
)),
552 Make_Attribute_Reference
(Loc
,
553 Prefix
=> New_Occurrence_Of
(E
, Loc
),
554 Attribute_Name
=> Name_Alignment
)),
555 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
556 Reason
=> PE_Misaligned_Address_Value
),
557 Suppress
=> All_Checks
);
564 when RE_Not_Available
=>
566 end Apply_Alignment_Check
;
568 -------------------------------------
569 -- Apply_Arithmetic_Overflow_Check --
570 -------------------------------------
572 -- This routine is called only if the type is an integer type, and
573 -- a software arithmetic overflow check must be performed for op
574 -- (add, subtract, multiply). The check is performed only if
575 -- Software_Overflow_Checking is enabled and Do_Overflow_Check
576 -- is set. In this case we expand the operation into a more complex
577 -- sequence of tests that ensures that overflow is properly caught.
579 procedure Apply_Arithmetic_Overflow_Check
(N
: Node_Id
) is
580 Loc
: constant Source_Ptr
:= Sloc
(N
);
581 Typ
: constant Entity_Id
:= Etype
(N
);
582 Rtyp
: constant Entity_Id
:= Root_Type
(Typ
);
583 Siz
: constant Int
:= UI_To_Int
(Esize
(Rtyp
));
584 Dsiz
: constant Int
:= Siz
* 2;
591 -- Skip this if overflow checks are done in back end, or the overflow
592 -- flag is not set anyway, or we are not doing code expansion.
594 if Backend_Overflow_Checks_On_Target
595 or else not Do_Overflow_Check
(N
)
596 or else not Expander_Active
601 -- Otherwise, we generate the full general code for front end overflow
602 -- detection, which works by doing arithmetic in a larger type:
608 -- Typ (Checktyp (x) op Checktyp (y));
610 -- where Typ is the type of the original expression, and Checktyp is
611 -- an integer type of sufficient length to hold the largest possible
614 -- In the case where check type exceeds the size of Long_Long_Integer,
615 -- we use a different approach, expanding to:
617 -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y)))
619 -- where xxx is Add, Multiply or Subtract as appropriate
621 -- Find check type if one exists
623 if Dsiz
<= Standard_Integer_Size
then
624 Ctyp
:= Standard_Integer
;
626 elsif Dsiz
<= Standard_Long_Long_Integer_Size
then
627 Ctyp
:= Standard_Long_Long_Integer
;
629 -- No check type exists, use runtime call
632 if Nkind
(N
) = N_Op_Add
then
633 Cent
:= RE_Add_With_Ovflo_Check
;
635 elsif Nkind
(N
) = N_Op_Multiply
then
636 Cent
:= RE_Multiply_With_Ovflo_Check
;
639 pragma Assert
(Nkind
(N
) = N_Op_Subtract
);
640 Cent
:= RE_Subtract_With_Ovflo_Check
;
645 Make_Function_Call
(Loc
,
646 Name
=> New_Reference_To
(RTE
(Cent
), Loc
),
647 Parameter_Associations
=> New_List
(
648 OK_Convert_To
(RTE
(RE_Integer_64
), Left_Opnd
(N
)),
649 OK_Convert_To
(RTE
(RE_Integer_64
), Right_Opnd
(N
))))));
651 Analyze_And_Resolve
(N
, Typ
);
655 -- If we fall through, we have the case where we do the arithmetic in
656 -- the next higher type and get the check by conversion. In these cases
657 -- Ctyp is set to the type to be used as the check type.
659 Opnod
:= Relocate_Node
(N
);
661 Opnd
:= OK_Convert_To
(Ctyp
, Left_Opnd
(Opnod
));
664 Set_Etype
(Opnd
, Ctyp
);
665 Set_Analyzed
(Opnd
, True);
666 Set_Left_Opnd
(Opnod
, Opnd
);
668 Opnd
:= OK_Convert_To
(Ctyp
, Right_Opnd
(Opnod
));
671 Set_Etype
(Opnd
, Ctyp
);
672 Set_Analyzed
(Opnd
, True);
673 Set_Right_Opnd
(Opnod
, Opnd
);
675 -- The type of the operation changes to the base type of the check
676 -- type, and we reset the overflow check indication, since clearly
677 -- no overflow is possible now that we are using a double length
678 -- type. We also set the Analyzed flag to avoid a recursive attempt
679 -- to expand the node.
681 Set_Etype
(Opnod
, Base_Type
(Ctyp
));
682 Set_Do_Overflow_Check
(Opnod
, False);
683 Set_Analyzed
(Opnod
, True);
685 -- Now build the outer conversion
687 Opnd
:= OK_Convert_To
(Typ
, Opnod
);
689 Set_Etype
(Opnd
, Typ
);
691 -- In the discrete type case, we directly generate the range check
692 -- for the outer operand. This range check will implement the required
695 if Is_Discrete_Type
(Typ
) then
697 Generate_Range_Check
(Expression
(N
), Typ
, CE_Overflow_Check_Failed
);
699 -- For other types, we enable overflow checking on the conversion,
700 -- after setting the node as analyzed to prevent recursive attempts
701 -- to expand the conversion node.
704 Set_Analyzed
(Opnd
, True);
705 Enable_Overflow_Check
(Opnd
);
710 when RE_Not_Available
=>
712 end Apply_Arithmetic_Overflow_Check
;
714 ----------------------------
715 -- Apply_Array_Size_Check --
716 ----------------------------
718 -- The situation is as follows. In GNAT 3 (GCC 2.x), the size in bits
719 -- is computed in 32 bits without an overflow check. That's a real
720 -- problem for Ada. So what we do in GNAT 3 is to approximate the
721 -- size of an array by manually multiplying the element size by the
722 -- number of elements, and comparing that against the allowed limits.
724 -- In GNAT 5, the size in byte is still computed in 32 bits without
725 -- an overflow check in the dynamic case, but the size in bits is
726 -- computed in 64 bits. We assume that's good enough, and we do not
727 -- bother to generate any front end test.
729 procedure Apply_Array_Size_Check
(N
: Node_Id
; Typ
: Entity_Id
) is
730 Loc
: constant Source_Ptr
:= Sloc
(N
);
731 Ctyp
: constant Entity_Id
:= Component_Type
(Typ
);
732 Ent
: constant Entity_Id
:= Defining_Identifier
(N
);
744 Static
: Boolean := True;
745 -- Set false if any index subtye bound is non-static
747 Umark
: constant Uintp
.Save_Mark
:= Uintp
.Mark
;
748 -- We can throw away all the Uint computations here, since they are
749 -- done only to generate boolean test results.
752 -- Size to check against
754 function Is_Address_Or_Import
(Decl
: Node_Id
) return Boolean;
755 -- Determines if Decl is an address clause or Import/Interface pragma
756 -- that references the defining identifier of the current declaration.
758 --------------------------
759 -- Is_Address_Or_Import --
760 --------------------------
762 function Is_Address_Or_Import
(Decl
: Node_Id
) return Boolean is
764 if Nkind
(Decl
) = N_At_Clause
then
765 return Chars
(Identifier
(Decl
)) = Chars
(Ent
);
767 elsif Nkind
(Decl
) = N_Attribute_Definition_Clause
then
769 Chars
(Decl
) = Name_Address
771 Nkind
(Name
(Decl
)) = N_Identifier
773 Chars
(Name
(Decl
)) = Chars
(Ent
);
775 elsif Nkind
(Decl
) = N_Pragma
then
776 if (Chars
(Decl
) = Name_Import
778 Chars
(Decl
) = Name_Interface
)
779 and then Present
(Pragma_Argument_Associations
(Decl
))
782 F
: constant Node_Id
:=
783 First
(Pragma_Argument_Associations
(Decl
));
791 Nkind
(Expression
(Next
(F
))) = N_Identifier
793 Chars
(Expression
(Next
(F
))) = Chars
(Ent
);
803 end Is_Address_Or_Import
;
805 -- Start of processing for Apply_Array_Size_Check
808 -- Do size check on local arrays. We only need this in the GCC 2
809 -- case, since in GCC 3, we expect the back end to properly handle
810 -- things. This routine can be removed when we baseline GNAT 3.
812 if Opt
.GCC_Version
>= 3 then
816 -- No need for a check if not expanding
818 if not Expander_Active
then
822 -- No need for a check if checks are suppressed
824 if Storage_Checks_Suppressed
(Typ
) then
828 -- It is pointless to insert this check inside an init proc, because
829 -- that's too late, we have already built the object to be the right
830 -- size, and if it's too large, too bad!
832 if Inside_Init_Proc
then
836 -- Look head for pragma interface/import or address clause applying
837 -- to this entity. If found, we suppress the check entirely. For now
838 -- we only look ahead 20 declarations to stop this becoming too slow
839 -- Note that eventually this whole routine gets moved to gigi.
842 for Ctr
in 1 .. 20 loop
846 if Is_Address_Or_Import
(Decl
) then
851 -- First step is to calculate the maximum number of elements. For
852 -- this calculation, we use the actual size of the subtype if it is
853 -- static, and if a bound of a subtype is non-static, we go to the
854 -- bound of the base type.
857 Indx
:= First_Index
(Typ
);
858 while Present
(Indx
) loop
859 Xtyp
:= Etype
(Indx
);
860 Lo
:= Type_Low_Bound
(Xtyp
);
861 Hi
:= Type_High_Bound
(Xtyp
);
863 -- If any bound raises constraint error, we will never get this
864 -- far, so there is no need to generate any kind of check.
866 if Raises_Constraint_Error
(Lo
)
868 Raises_Constraint_Error
(Hi
)
870 Uintp
.Release
(Umark
);
874 -- Otherwise get bounds values
876 if Is_Static_Expression
(Lo
) then
877 Lob
:= Expr_Value
(Lo
);
879 Lob
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Xtyp
)));
883 if Is_Static_Expression
(Hi
) then
884 Hib
:= Expr_Value
(Hi
);
886 Hib
:= Expr_Value
(Type_High_Bound
(Base_Type
(Xtyp
)));
890 Siz
:= Siz
* UI_Max
(Hib
- Lob
+ 1, Uint_0
);
894 -- Compute the limit against which we want to check. For subprograms,
895 -- where the array will go on the stack, we use 8*2**24, which (in
896 -- bits) is the size of a 16 megabyte array.
898 if Is_Subprogram
(Scope
(Ent
)) then
899 Check_Siz
:= Uint_2
** 27;
901 Check_Siz
:= Uint_2
** 31;
904 -- If we have all static bounds and Siz is too large, then we know
905 -- we know we have a storage error right now, so generate message
907 if Static
and then Siz
>= Check_Siz
then
909 Make_Raise_Storage_Error
(Loc
,
910 Reason
=> SE_Object_Too_Large
));
911 Error_Msg_N
("?Storage_Error will be raised at run-time", N
);
912 Uintp
.Release
(Umark
);
916 -- Case of component size known at compile time. If the array
917 -- size is definitely in range, then we do not need a check.
919 if Known_Esize
(Ctyp
)
920 and then Siz
* Esize
(Ctyp
) < Check_Siz
922 Uintp
.Release
(Umark
);
926 -- Here if a dynamic check is required
928 -- What we do is to build an expression for the size of the array,
929 -- which is computed as the 'Size of the array component, times
930 -- the size of each dimension.
932 Uintp
.Release
(Umark
);
935 Make_Attribute_Reference
(Loc
,
936 Prefix
=> New_Occurrence_Of
(Ctyp
, Loc
),
937 Attribute_Name
=> Name_Size
);
939 Indx
:= First_Index
(Typ
);
940 for J
in 1 .. Number_Dimensions
(Typ
) loop
941 if Sloc
(Etype
(Indx
)) = Sloc
(N
) then
942 Ensure_Defined
(Etype
(Indx
), N
);
946 Make_Op_Multiply
(Loc
,
949 Make_Attribute_Reference
(Loc
,
950 Prefix
=> New_Occurrence_Of
(Typ
, Loc
),
951 Attribute_Name
=> Name_Length
,
952 Expressions
=> New_List
(
953 Make_Integer_Literal
(Loc
, J
))));
960 Make_Raise_Storage_Error
(Loc
,
965 Make_Integer_Literal
(Loc
,
966 Intval
=> Check_Siz
)),
967 Reason
=> SE_Object_Too_Large
);
969 Set_Size_Check_Code
(Defining_Identifier
(N
), Code
);
970 Insert_Action
(N
, Code
, Suppress
=> All_Checks
);
971 end Apply_Array_Size_Check
;
973 ----------------------------
974 -- Apply_Constraint_Check --
975 ----------------------------
977 procedure Apply_Constraint_Check
980 No_Sliding
: Boolean := False)
982 Desig_Typ
: Entity_Id
;
985 if Inside_A_Generic
then
988 elsif Is_Scalar_Type
(Typ
) then
989 Apply_Scalar_Range_Check
(N
, Typ
);
991 elsif Is_Array_Type
(Typ
) then
993 -- A useful optimization: an aggregate with only an others clause
994 -- always has the right bounds.
996 if Nkind
(N
) = N_Aggregate
997 and then No
(Expressions
(N
))
999 (First
(Choices
(First
(Component_Associations
(N
)))))
1005 if Is_Constrained
(Typ
) then
1006 Apply_Length_Check
(N
, Typ
);
1009 Apply_Range_Check
(N
, Typ
);
1012 Apply_Range_Check
(N
, Typ
);
1015 elsif (Is_Record_Type
(Typ
)
1016 or else Is_Private_Type
(Typ
))
1017 and then Has_Discriminants
(Base_Type
(Typ
))
1018 and then Is_Constrained
(Typ
)
1020 Apply_Discriminant_Check
(N
, Typ
);
1022 elsif Is_Access_Type
(Typ
) then
1024 Desig_Typ
:= Designated_Type
(Typ
);
1026 -- No checks necessary if expression statically null
1028 if Nkind
(N
) = N_Null
then
1031 -- No sliding possible on access to arrays
1033 elsif Is_Array_Type
(Desig_Typ
) then
1034 if Is_Constrained
(Desig_Typ
) then
1035 Apply_Length_Check
(N
, Typ
);
1038 Apply_Range_Check
(N
, Typ
);
1040 elsif Has_Discriminants
(Base_Type
(Desig_Typ
))
1041 and then Is_Constrained
(Desig_Typ
)
1043 Apply_Discriminant_Check
(N
, Typ
);
1046 if Can_Never_Be_Null
(Typ
)
1047 and then not Can_Never_Be_Null
(Etype
(N
))
1049 Install_Null_Excluding_Check
(N
);
1052 end Apply_Constraint_Check
;
1054 ------------------------------
1055 -- Apply_Discriminant_Check --
1056 ------------------------------
1058 procedure Apply_Discriminant_Check
1061 Lhs
: Node_Id
:= Empty
)
1063 Loc
: constant Source_Ptr
:= Sloc
(N
);
1064 Do_Access
: constant Boolean := Is_Access_Type
(Typ
);
1065 S_Typ
: Entity_Id
:= Etype
(N
);
1069 function Is_Aliased_Unconstrained_Component
return Boolean;
1070 -- It is possible for an aliased component to have a nominal
1071 -- unconstrained subtype (through instantiation). If this is a
1072 -- discriminated component assigned in the expansion of an aggregate
1073 -- in an initialization, the check must be suppressed. This unusual
1074 -- situation requires a predicate of its own (see 7503-008).
1076 ----------------------------------------
1077 -- Is_Aliased_Unconstrained_Component --
1078 ----------------------------------------
1080 function Is_Aliased_Unconstrained_Component
return Boolean is
1085 if Nkind
(Lhs
) /= N_Selected_Component
then
1088 Comp
:= Entity
(Selector_Name
(Lhs
));
1089 Pref
:= Prefix
(Lhs
);
1092 if Ekind
(Comp
) /= E_Component
1093 or else not Is_Aliased
(Comp
)
1098 return not Comes_From_Source
(Pref
)
1099 and then In_Instance
1100 and then not Is_Constrained
(Etype
(Comp
));
1101 end Is_Aliased_Unconstrained_Component
;
1103 -- Start of processing for Apply_Discriminant_Check
1107 T_Typ
:= Designated_Type
(Typ
);
1112 -- Nothing to do if discriminant checks are suppressed or else no code
1113 -- is to be generated
1115 if not Expander_Active
1116 or else Discriminant_Checks_Suppressed
(T_Typ
)
1121 -- No discriminant checks necessary for an access when expression
1122 -- is statically Null. This is not only an optimization, this is
1123 -- fundamental because otherwise discriminant checks may be generated
1124 -- in init procs for types containing an access to a not-yet-frozen
1125 -- record, causing a deadly forward reference.
1127 -- Also, if the expression is of an access type whose designated
1128 -- type is incomplete, then the access value must be null and
1129 -- we suppress the check.
1131 if Nkind
(N
) = N_Null
then
1134 elsif Is_Access_Type
(S_Typ
) then
1135 S_Typ
:= Designated_Type
(S_Typ
);
1137 if Ekind
(S_Typ
) = E_Incomplete_Type
then
1142 -- If an assignment target is present, then we need to generate
1143 -- the actual subtype if the target is a parameter or aliased
1144 -- object with an unconstrained nominal subtype.
1147 and then (Present
(Param_Entity
(Lhs
))
1148 or else (not Is_Constrained
(T_Typ
)
1149 and then Is_Aliased_View
(Lhs
)
1150 and then not Is_Aliased_Unconstrained_Component
))
1152 T_Typ
:= Get_Actual_Subtype
(Lhs
);
1155 -- Nothing to do if the type is unconstrained (this is the case
1156 -- where the actual subtype in the RM sense of N is unconstrained
1157 -- and no check is required).
1159 if not Is_Constrained
(T_Typ
) then
1162 -- Ada 2005: nothing to do if the type is one for which there is a
1163 -- partial view that is constrained.
1165 elsif Ada_Version
>= Ada_05
1166 and then Has_Constrained_Partial_View
(Base_Type
(T_Typ
))
1171 -- Nothing to do if the type is an Unchecked_Union
1173 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
1177 -- Suppress checks if the subtypes are the same.
1178 -- the check must be preserved in an assignment to a formal, because
1179 -- the constraint is given by the actual.
1181 if Nkind
(Original_Node
(N
)) /= N_Allocator
1183 or else not Is_Entity_Name
(Lhs
)
1184 or else No
(Param_Entity
(Lhs
)))
1187 or else (Do_Access
and then Designated_Type
(Typ
) = S_Typ
))
1188 and then not Is_Aliased_View
(Lhs
)
1193 -- We can also eliminate checks on allocators with a subtype mark
1194 -- that coincides with the context type. The context type may be a
1195 -- subtype without a constraint (common case, a generic actual).
1197 elsif Nkind
(Original_Node
(N
)) = N_Allocator
1198 and then Is_Entity_Name
(Expression
(Original_Node
(N
)))
1201 Alloc_Typ
: constant Entity_Id
:=
1202 Entity
(Expression
(Original_Node
(N
)));
1205 if Alloc_Typ
= T_Typ
1206 or else (Nkind
(Parent
(T_Typ
)) = N_Subtype_Declaration
1207 and then Is_Entity_Name
(
1208 Subtype_Indication
(Parent
(T_Typ
)))
1209 and then Alloc_Typ
= Base_Type
(T_Typ
))
1217 -- See if we have a case where the types are both constrained, and
1218 -- all the constraints are constants. In this case, we can do the
1219 -- check successfully at compile time.
1221 -- We skip this check for the case where the node is a rewritten`
1222 -- allocator, because it already carries the context subtype, and
1223 -- extracting the discriminants from the aggregate is messy.
1225 if Is_Constrained
(S_Typ
)
1226 and then Nkind
(Original_Node
(N
)) /= N_Allocator
1236 -- S_Typ may not have discriminants in the case where it is a
1237 -- private type completed by a default discriminated type. In
1238 -- that case, we need to get the constraints from the
1239 -- underlying_type. If the underlying type is unconstrained (i.e.
1240 -- has no default discriminants) no check is needed.
1242 if Has_Discriminants
(S_Typ
) then
1243 Discr
:= First_Discriminant
(S_Typ
);
1244 DconS
:= First_Elmt
(Discriminant_Constraint
(S_Typ
));
1247 Discr
:= First_Discriminant
(Underlying_Type
(S_Typ
));
1250 (Discriminant_Constraint
(Underlying_Type
(S_Typ
)));
1256 -- A further optimization: if T_Typ is derived from S_Typ
1257 -- without imposing a constraint, no check is needed.
1259 if Nkind
(Original_Node
(Parent
(T_Typ
))) =
1260 N_Full_Type_Declaration
1263 Type_Def
: constant Node_Id
:=
1265 (Original_Node
(Parent
(T_Typ
)));
1267 if Nkind
(Type_Def
) = N_Derived_Type_Definition
1268 and then Is_Entity_Name
(Subtype_Indication
(Type_Def
))
1269 and then Entity
(Subtype_Indication
(Type_Def
)) = S_Typ
1277 DconT
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
1279 while Present
(Discr
) loop
1280 ItemS
:= Node
(DconS
);
1281 ItemT
:= Node
(DconT
);
1284 not Is_OK_Static_Expression
(ItemS
)
1286 not Is_OK_Static_Expression
(ItemT
);
1288 if Expr_Value
(ItemS
) /= Expr_Value
(ItemT
) then
1289 if Do_Access
then -- needs run-time check.
1292 Apply_Compile_Time_Constraint_Error
1293 (N
, "incorrect value for discriminant&?",
1294 CE_Discriminant_Check_Failed
, Ent
=> Discr
);
1301 Next_Discriminant
(Discr
);
1310 -- Here we need a discriminant check. First build the expression
1311 -- for the comparisons of the discriminants:
1313 -- (n.disc1 /= typ.disc1) or else
1314 -- (n.disc2 /= typ.disc2) or else
1316 -- (n.discn /= typ.discn)
1318 Cond
:= Build_Discriminant_Checks
(N
, T_Typ
);
1320 -- If Lhs is set and is a parameter, then the condition is
1321 -- guarded by: lhs'constrained and then (condition built above)
1323 if Present
(Param_Entity
(Lhs
)) then
1327 Make_Attribute_Reference
(Loc
,
1328 Prefix
=> New_Occurrence_Of
(Param_Entity
(Lhs
), Loc
),
1329 Attribute_Name
=> Name_Constrained
),
1330 Right_Opnd
=> Cond
);
1334 Cond
:= Guard_Access
(Cond
, Loc
, N
);
1338 Make_Raise_Constraint_Error
(Loc
,
1340 Reason
=> CE_Discriminant_Check_Failed
));
1341 end Apply_Discriminant_Check
;
1343 ------------------------
1344 -- Apply_Divide_Check --
1345 ------------------------
1347 procedure Apply_Divide_Check
(N
: Node_Id
) is
1348 Loc
: constant Source_Ptr
:= Sloc
(N
);
1349 Typ
: constant Entity_Id
:= Etype
(N
);
1350 Left
: constant Node_Id
:= Left_Opnd
(N
);
1351 Right
: constant Node_Id
:= Right_Opnd
(N
);
1363 and not Backend_Divide_Checks_On_Target
1365 Determine_Range
(Right
, ROK
, Rlo
, Rhi
);
1367 -- See if division by zero possible, and if so generate test. This
1368 -- part of the test is not controlled by the -gnato switch.
1370 if Do_Division_Check
(N
) then
1371 if (not ROK
) or else (Rlo
<= 0 and then 0 <= Rhi
) then
1373 Make_Raise_Constraint_Error
(Loc
,
1376 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(Right
),
1377 Right_Opnd
=> Make_Integer_Literal
(Loc
, 0)),
1378 Reason
=> CE_Divide_By_Zero
));
1382 -- Test for extremely annoying case of xxx'First divided by -1
1384 if Do_Overflow_Check
(N
) then
1386 if Nkind
(N
) = N_Op_Divide
1387 and then Is_Signed_Integer_Type
(Typ
)
1389 Determine_Range
(Left
, LOK
, Llo
, Lhi
);
1390 LLB
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
1392 if ((not ROK
) or else (Rlo
<= (-1) and then (-1) <= Rhi
))
1394 ((not LOK
) or else (Llo
= LLB
))
1397 Make_Raise_Constraint_Error
(Loc
,
1403 Duplicate_Subexpr_Move_Checks
(Left
),
1404 Right_Opnd
=> Make_Integer_Literal
(Loc
, LLB
)),
1408 Duplicate_Subexpr
(Right
),
1410 Make_Integer_Literal
(Loc
, -1))),
1411 Reason
=> CE_Overflow_Check_Failed
));
1416 end Apply_Divide_Check
;
1418 ----------------------------------
1419 -- Apply_Float_Conversion_Check --
1420 ----------------------------------
1422 -- Let F and I be the source and target types of the conversion.
1423 -- The Ada standard specifies that a floating-point value X is rounded
1424 -- to the nearest integer, with halfway cases being rounded away from
1425 -- zero. The rounded value of X is checked against I'Range.
1427 -- The catch in the above paragraph is that there is no good way
1428 -- to know whether the round-to-integer operation resulted in
1429 -- overflow. A remedy is to perform a range check in the floating-point
1430 -- domain instead, however:
1431 -- (1) The bounds may not be known at compile time
1432 -- (2) The check must take into account possible rounding.
1433 -- (3) The range of type I may not be exactly representable in F.
1434 -- (4) The end-points I'First - 0.5 and I'Last + 0.5 may or may
1435 -- not be in range, depending on the sign of I'First and I'Last.
1436 -- (5) X may be a NaN, which will fail any comparison
1438 -- The following steps take care of these issues converting X:
1439 -- (1) If either I'First or I'Last is not known at compile time, use
1440 -- I'Base instead of I in the next three steps and perform a
1441 -- regular range check against I'Range after conversion.
1442 -- (2) If I'First - 0.5 is representable in F then let Lo be that
1443 -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be
1444 -- F'Machine (T) and let Lo_OK be (Lo >= I'First). In other words,
1445 -- take one of the closest floating-point numbers to T, and see if
1446 -- it is in range or not.
1447 -- (3) If I'Last + 0.5 is representable in F then let Hi be that value
1448 -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be
1449 -- F'Rounding (T) and let Hi_OK be (Hi <= I'Last).
1450 -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo)
1451 -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi)
1453 procedure Apply_Float_Conversion_Check
1455 Target_Typ
: Entity_Id
)
1457 LB
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1458 HB
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1459 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1460 Expr_Type
: constant Entity_Id
:= Base_Type
(Etype
(Ck_Node
));
1461 Target_Base
: constant Entity_Id
:= Implementation_Base_Type
1463 Max_Bound
: constant Uint
:= UI_Expon
1464 (Machine_Radix
(Expr_Type
),
1465 Machine_Mantissa
(Expr_Type
) - 1) - 1;
1466 -- Largest bound, so bound plus or minus half is a machine number of F
1469 Ilast
: Uint
; -- Bounds of integer type
1470 Lo
, Hi
: Ureal
; -- Bounds to check in floating-point domain
1472 Hi_OK
: Boolean; -- True iff Lo resp. Hi belongs to I'Range
1475 Hi_Chk
: Node_Id
; -- Expressions that are False iff check fails
1477 Reason
: RT_Exception_Code
;
1480 if not Compile_Time_Known_Value
(LB
)
1481 or not Compile_Time_Known_Value
(HB
)
1484 -- First check that the value falls in the range of the base
1485 -- type, to prevent overflow during conversion and then
1486 -- perform a regular range check against the (dynamic) bounds.
1488 Par
: constant Node_Id
:= Parent
(Ck_Node
);
1490 pragma Assert
(Target_Base
/= Target_Typ
);
1491 pragma Assert
(Nkind
(Par
) = N_Type_Conversion
);
1493 Temp
: constant Entity_Id
:=
1494 Make_Defining_Identifier
(Loc
,
1495 Chars
=> New_Internal_Name
('T'));
1498 Apply_Float_Conversion_Check
(Ck_Node
, Target_Base
);
1499 Set_Etype
(Temp
, Target_Base
);
1501 Insert_Action
(Parent
(Par
),
1502 Make_Object_Declaration
(Loc
,
1503 Defining_Identifier
=> Temp
,
1504 Object_Definition
=> New_Occurrence_Of
(Target_Typ
, Loc
),
1505 Expression
=> New_Copy_Tree
(Par
)),
1506 Suppress
=> All_Checks
);
1509 Make_Raise_Constraint_Error
(Loc
,
1512 Left_Opnd
=> New_Occurrence_Of
(Temp
, Loc
),
1513 Right_Opnd
=> New_Occurrence_Of
(Target_Typ
, Loc
)),
1514 Reason
=> CE_Range_Check_Failed
));
1515 Rewrite
(Par
, New_Occurrence_Of
(Temp
, Loc
));
1521 -- Get the bounds of the target type
1523 Ifirst
:= Expr_Value
(LB
);
1524 Ilast
:= Expr_Value
(HB
);
1526 -- Check against lower bound
1528 if abs (Ifirst
) < Max_Bound
then
1529 Lo
:= UR_From_Uint
(Ifirst
) - Ureal_Half
;
1530 Lo_OK
:= (Ifirst
> 0);
1532 Lo
:= Machine
(Expr_Type
, UR_From_Uint
(Ifirst
), Round_Even
, Ck_Node
);
1533 Lo_OK
:= (Lo
>= UR_From_Uint
(Ifirst
));
1538 -- Lo_Chk := (X >= Lo)
1540 Lo_Chk
:= Make_Op_Ge
(Loc
,
1541 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1542 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
1545 -- Lo_Chk := (X > Lo)
1547 Lo_Chk
:= Make_Op_Gt
(Loc
,
1548 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1549 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
1552 -- Check against higher bound
1554 if abs (Ilast
) < Max_Bound
then
1555 Hi
:= UR_From_Uint
(Ilast
) + Ureal_Half
;
1556 Hi_OK
:= (Ilast
< 0);
1558 Hi
:= Machine
(Expr_Type
, UR_From_Uint
(Ilast
), Round_Even
, Ck_Node
);
1559 Hi_OK
:= (Hi
<= UR_From_Uint
(Ilast
));
1564 -- Hi_Chk := (X <= Hi)
1566 Hi_Chk
:= Make_Op_Le
(Loc
,
1567 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1568 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
1571 -- Hi_Chk := (X < Hi)
1573 Hi_Chk
:= Make_Op_Lt
(Loc
,
1574 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
1575 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
1578 -- If the bounds of the target type are the same as those of the
1579 -- base type, the check is an overflow check as a range check is
1580 -- not performed in these cases.
1582 if Expr_Value
(Type_Low_Bound
(Target_Base
)) = Ifirst
1583 and then Expr_Value
(Type_High_Bound
(Target_Base
)) = Ilast
1585 Reason
:= CE_Overflow_Check_Failed
;
1587 Reason
:= CE_Range_Check_Failed
;
1590 -- Raise CE if either conditions does not hold
1592 Insert_Action
(Ck_Node
,
1593 Make_Raise_Constraint_Error
(Loc
,
1594 Condition
=> Make_Op_Not
(Loc
, Make_And_Then
(Loc
, Lo_Chk
, Hi_Chk
)),
1596 end Apply_Float_Conversion_Check
;
1598 ------------------------
1599 -- Apply_Length_Check --
1600 ------------------------
1602 procedure Apply_Length_Check
1604 Target_Typ
: Entity_Id
;
1605 Source_Typ
: Entity_Id
:= Empty
)
1608 Apply_Selected_Length_Checks
1609 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
1610 end Apply_Length_Check
;
1612 -----------------------
1613 -- Apply_Range_Check --
1614 -----------------------
1616 procedure Apply_Range_Check
1618 Target_Typ
: Entity_Id
;
1619 Source_Typ
: Entity_Id
:= Empty
)
1622 Apply_Selected_Range_Checks
1623 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
1624 end Apply_Range_Check
;
1626 ------------------------------
1627 -- Apply_Scalar_Range_Check --
1628 ------------------------------
1630 -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check
1631 -- flag off if it is already set on.
1633 procedure Apply_Scalar_Range_Check
1635 Target_Typ
: Entity_Id
;
1636 Source_Typ
: Entity_Id
:= Empty
;
1637 Fixed_Int
: Boolean := False)
1639 Parnt
: constant Node_Id
:= Parent
(Expr
);
1641 Arr
: Node_Id
:= Empty
; -- initialize to prevent warning
1642 Arr_Typ
: Entity_Id
:= Empty
; -- initialize to prevent warning
1645 Is_Subscr_Ref
: Boolean;
1646 -- Set true if Expr is a subscript
1648 Is_Unconstrained_Subscr_Ref
: Boolean;
1649 -- Set true if Expr is a subscript of an unconstrained array. In this
1650 -- case we do not attempt to do an analysis of the value against the
1651 -- range of the subscript, since we don't know the actual subtype.
1654 -- Set to True if Expr should be regarded as a real value
1655 -- even though the type of Expr might be discrete.
1657 procedure Bad_Value
;
1658 -- Procedure called if value is determined to be out of range
1664 procedure Bad_Value
is
1666 Apply_Compile_Time_Constraint_Error
1667 (Expr
, "value not in range of}?", CE_Range_Check_Failed
,
1672 -- Start of processing for Apply_Scalar_Range_Check
1675 if Inside_A_Generic
then
1678 -- Return if check obviously not needed. Note that we do not check
1679 -- for the expander being inactive, since this routine does not
1680 -- insert any code, but it does generate useful warnings sometimes,
1681 -- which we would like even if we are in semantics only mode.
1683 elsif Target_Typ
= Any_Type
1684 or else not Is_Scalar_Type
(Target_Typ
)
1685 or else Raises_Constraint_Error
(Expr
)
1690 -- Now, see if checks are suppressed
1693 Is_List_Member
(Expr
) and then Nkind
(Parnt
) = N_Indexed_Component
;
1695 if Is_Subscr_Ref
then
1696 Arr
:= Prefix
(Parnt
);
1697 Arr_Typ
:= Get_Actual_Subtype_If_Available
(Arr
);
1700 if not Do_Range_Check
(Expr
) then
1702 -- Subscript reference. Check for Index_Checks suppressed
1704 if Is_Subscr_Ref
then
1706 -- Check array type and its base type
1708 if Index_Checks_Suppressed
(Arr_Typ
)
1709 or else Index_Checks_Suppressed
(Base_Type
(Arr_Typ
))
1713 -- Check array itself if it is an entity name
1715 elsif Is_Entity_Name
(Arr
)
1716 and then Index_Checks_Suppressed
(Entity
(Arr
))
1720 -- Check expression itself if it is an entity name
1722 elsif Is_Entity_Name
(Expr
)
1723 and then Index_Checks_Suppressed
(Entity
(Expr
))
1728 -- All other cases, check for Range_Checks suppressed
1731 -- Check target type and its base type
1733 if Range_Checks_Suppressed
(Target_Typ
)
1734 or else Range_Checks_Suppressed
(Base_Type
(Target_Typ
))
1738 -- Check expression itself if it is an entity name
1740 elsif Is_Entity_Name
(Expr
)
1741 and then Range_Checks_Suppressed
(Entity
(Expr
))
1745 -- If Expr is part of an assignment statement, then check
1746 -- left side of assignment if it is an entity name.
1748 elsif Nkind
(Parnt
) = N_Assignment_Statement
1749 and then Is_Entity_Name
(Name
(Parnt
))
1750 and then Range_Checks_Suppressed
(Entity
(Name
(Parnt
)))
1757 -- Do not set range checks if they are killed
1759 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
1760 and then Kill_Range_Check
(Expr
)
1765 -- Do not set range checks for any values from System.Scalar_Values
1766 -- since the whole idea of such values is to avoid checking them!
1768 if Is_Entity_Name
(Expr
)
1769 and then Is_RTU
(Scope
(Entity
(Expr
)), System_Scalar_Values
)
1774 -- Now see if we need a check
1776 if No
(Source_Typ
) then
1777 S_Typ
:= Etype
(Expr
);
1779 S_Typ
:= Source_Typ
;
1782 if not Is_Scalar_Type
(S_Typ
) or else S_Typ
= Any_Type
then
1786 Is_Unconstrained_Subscr_Ref
:=
1787 Is_Subscr_Ref
and then not Is_Constrained
(Arr_Typ
);
1789 -- Always do a range check if the source type includes infinities
1790 -- and the target type does not include infinities. We do not do
1791 -- this if range checks are killed.
1793 if Is_Floating_Point_Type
(S_Typ
)
1794 and then Has_Infinities
(S_Typ
)
1795 and then not Has_Infinities
(Target_Typ
)
1797 Enable_Range_Check
(Expr
);
1800 -- Return if we know expression is definitely in the range of
1801 -- the target type as determined by Determine_Range. Right now
1802 -- we only do this for discrete types, and not fixed-point or
1803 -- floating-point types.
1805 -- The additional less-precise tests below catch these cases
1807 -- Note: skip this if we are given a source_typ, since the point
1808 -- of supplying a Source_Typ is to stop us looking at the expression.
1809 -- could sharpen this test to be out parameters only ???
1811 if Is_Discrete_Type
(Target_Typ
)
1812 and then Is_Discrete_Type
(Etype
(Expr
))
1813 and then not Is_Unconstrained_Subscr_Ref
1814 and then No
(Source_Typ
)
1817 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1818 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1823 if Compile_Time_Known_Value
(Tlo
)
1824 and then Compile_Time_Known_Value
(Thi
)
1827 Lov
: constant Uint
:= Expr_Value
(Tlo
);
1828 Hiv
: constant Uint
:= Expr_Value
(Thi
);
1831 -- If range is null, we for sure have a constraint error
1832 -- (we don't even need to look at the value involved,
1833 -- since all possible values will raise CE).
1840 -- Otherwise determine range of value
1842 Determine_Range
(Expr
, OK
, Lo
, Hi
);
1846 -- If definitely in range, all OK
1848 if Lo
>= Lov
and then Hi
<= Hiv
then
1851 -- If definitely not in range, warn
1853 elsif Lov
> Hi
or else Hiv
< Lo
then
1857 -- Otherwise we don't know
1869 Is_Floating_Point_Type
(S_Typ
)
1870 or else (Is_Fixed_Point_Type
(S_Typ
) and then not Fixed_Int
);
1872 -- Check if we can determine at compile time whether Expr is in the
1873 -- range of the target type. Note that if S_Typ is within the bounds
1874 -- of Target_Typ then this must be the case. This check is meaningful
1875 -- only if this is not a conversion between integer and real types.
1877 if not Is_Unconstrained_Subscr_Ref
1879 Is_Discrete_Type
(S_Typ
) = Is_Discrete_Type
(Target_Typ
)
1881 (In_Subrange_Of
(S_Typ
, Target_Typ
, Fixed_Int
)
1883 Is_In_Range
(Expr
, Target_Typ
, Fixed_Int
, Int_Real
))
1887 elsif Is_Out_Of_Range
(Expr
, Target_Typ
, Fixed_Int
, Int_Real
) then
1891 -- In the floating-point case, we only do range checks if the
1892 -- type is constrained. We definitely do NOT want range checks
1893 -- for unconstrained types, since we want to have infinities
1895 elsif Is_Floating_Point_Type
(S_Typ
) then
1896 if Is_Constrained
(S_Typ
) then
1897 Enable_Range_Check
(Expr
);
1900 -- For all other cases we enable a range check unconditionally
1903 Enable_Range_Check
(Expr
);
1906 end Apply_Scalar_Range_Check
;
1908 ----------------------------------
1909 -- Apply_Selected_Length_Checks --
1910 ----------------------------------
1912 procedure Apply_Selected_Length_Checks
1914 Target_Typ
: Entity_Id
;
1915 Source_Typ
: Entity_Id
;
1916 Do_Static
: Boolean)
1919 R_Result
: Check_Result
;
1922 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1923 Checks_On
: constant Boolean :=
1924 (not Index_Checks_Suppressed
(Target_Typ
))
1926 (not Length_Checks_Suppressed
(Target_Typ
));
1929 if not Expander_Active
then
1934 Selected_Length_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
1936 for J
in 1 .. 2 loop
1937 R_Cno
:= R_Result
(J
);
1938 exit when No
(R_Cno
);
1940 -- A length check may mention an Itype which is attached to a
1941 -- subsequent node. At the top level in a package this can cause
1942 -- an order-of-elaboration problem, so we make sure that the itype
1943 -- is referenced now.
1945 if Ekind
(Current_Scope
) = E_Package
1946 and then Is_Compilation_Unit
(Current_Scope
)
1948 Ensure_Defined
(Target_Typ
, Ck_Node
);
1950 if Present
(Source_Typ
) then
1951 Ensure_Defined
(Source_Typ
, Ck_Node
);
1953 elsif Is_Itype
(Etype
(Ck_Node
)) then
1954 Ensure_Defined
(Etype
(Ck_Node
), Ck_Node
);
1958 -- If the item is a conditional raise of constraint error,
1959 -- then have a look at what check is being performed and
1962 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
1963 and then Present
(Condition
(R_Cno
))
1965 Cond
:= Condition
(R_Cno
);
1967 if not Has_Dynamic_Length_Check
(Ck_Node
)
1970 Insert_Action
(Ck_Node
, R_Cno
);
1972 if not Do_Static
then
1973 Set_Has_Dynamic_Length_Check
(Ck_Node
);
1977 -- Output a warning if the condition is known to be True
1979 if Is_Entity_Name
(Cond
)
1980 and then Entity
(Cond
) = Standard_True
1982 Apply_Compile_Time_Constraint_Error
1983 (Ck_Node
, "wrong length for array of}?",
1984 CE_Length_Check_Failed
,
1988 -- If we were only doing a static check, or if checks are not
1989 -- on, then we want to delete the check, since it is not needed.
1990 -- We do this by replacing the if statement by a null statement
1992 elsif Do_Static
or else not Checks_On
then
1993 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
1997 Install_Static_Check
(R_Cno
, Loc
);
2002 end Apply_Selected_Length_Checks
;
2004 ---------------------------------
2005 -- Apply_Selected_Range_Checks --
2006 ---------------------------------
2008 procedure Apply_Selected_Range_Checks
2010 Target_Typ
: Entity_Id
;
2011 Source_Typ
: Entity_Id
;
2012 Do_Static
: Boolean)
2015 R_Result
: Check_Result
;
2018 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
2019 Checks_On
: constant Boolean :=
2020 (not Index_Checks_Suppressed
(Target_Typ
))
2022 (not Range_Checks_Suppressed
(Target_Typ
));
2025 if not Expander_Active
or else not Checks_On
then
2030 Selected_Range_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
2032 for J
in 1 .. 2 loop
2034 R_Cno
:= R_Result
(J
);
2035 exit when No
(R_Cno
);
2037 -- If the item is a conditional raise of constraint error,
2038 -- then have a look at what check is being performed and
2041 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
2042 and then Present
(Condition
(R_Cno
))
2044 Cond
:= Condition
(R_Cno
);
2046 if not Has_Dynamic_Range_Check
(Ck_Node
) then
2047 Insert_Action
(Ck_Node
, R_Cno
);
2049 if not Do_Static
then
2050 Set_Has_Dynamic_Range_Check
(Ck_Node
);
2054 -- Output a warning if the condition is known to be True
2056 if Is_Entity_Name
(Cond
)
2057 and then Entity
(Cond
) = Standard_True
2059 -- Since an N_Range is technically not an expression, we
2060 -- have to set one of the bounds to C_E and then just flag
2061 -- the N_Range. The warning message will point to the
2062 -- lower bound and complain about a range, which seems OK.
2064 if Nkind
(Ck_Node
) = N_Range
then
2065 Apply_Compile_Time_Constraint_Error
2066 (Low_Bound
(Ck_Node
), "static range out of bounds of}?",
2067 CE_Range_Check_Failed
,
2071 Set_Raises_Constraint_Error
(Ck_Node
);
2074 Apply_Compile_Time_Constraint_Error
2075 (Ck_Node
, "static value out of range of}?",
2076 CE_Range_Check_Failed
,
2081 -- If we were only doing a static check, or if checks are not
2082 -- on, then we want to delete the check, since it is not needed.
2083 -- We do this by replacing the if statement by a null statement
2085 elsif Do_Static
or else not Checks_On
then
2086 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
2090 Install_Static_Check
(R_Cno
, Loc
);
2093 end Apply_Selected_Range_Checks
;
2095 -------------------------------
2096 -- Apply_Static_Length_Check --
2097 -------------------------------
2099 procedure Apply_Static_Length_Check
2101 Target_Typ
: Entity_Id
;
2102 Source_Typ
: Entity_Id
:= Empty
)
2105 Apply_Selected_Length_Checks
2106 (Expr
, Target_Typ
, Source_Typ
, Do_Static
=> True);
2107 end Apply_Static_Length_Check
;
2109 -------------------------------------
2110 -- Apply_Subscript_Validity_Checks --
2111 -------------------------------------
2113 procedure Apply_Subscript_Validity_Checks
(Expr
: Node_Id
) is
2117 pragma Assert
(Nkind
(Expr
) = N_Indexed_Component
);
2119 -- Loop through subscripts
2121 Sub
:= First
(Expressions
(Expr
));
2122 while Present
(Sub
) loop
2124 -- Check one subscript. Note that we do not worry about
2125 -- enumeration type with holes, since we will convert the
2126 -- value to a Pos value for the subscript, and that convert
2127 -- will do the necessary validity check.
2129 Ensure_Valid
(Sub
, Holes_OK
=> True);
2131 -- Move to next subscript
2135 end Apply_Subscript_Validity_Checks
;
2137 ----------------------------------
2138 -- Apply_Type_Conversion_Checks --
2139 ----------------------------------
2141 procedure Apply_Type_Conversion_Checks
(N
: Node_Id
) is
2142 Target_Type
: constant Entity_Id
:= Etype
(N
);
2143 Target_Base
: constant Entity_Id
:= Base_Type
(Target_Type
);
2144 Expr
: constant Node_Id
:= Expression
(N
);
2145 Expr_Type
: constant Entity_Id
:= Etype
(Expr
);
2148 if Inside_A_Generic
then
2151 -- Skip these checks if serious errors detected, there are some nasty
2152 -- situations of incomplete trees that blow things up.
2154 elsif Serious_Errors_Detected
> 0 then
2157 -- Scalar type conversions of the form Target_Type (Expr) require
2158 -- a range check if we cannot be sure that Expr is in the base type
2159 -- of Target_Typ and also that Expr is in the range of Target_Typ.
2160 -- These are not quite the same condition from an implementation
2161 -- point of view, but clearly the second includes the first.
2163 elsif Is_Scalar_Type
(Target_Type
) then
2165 Conv_OK
: constant Boolean := Conversion_OK
(N
);
2166 -- If the Conversion_OK flag on the type conversion is set
2167 -- and no floating point type is involved in the type conversion
2168 -- then fixed point values must be read as integral values.
2170 Float_To_Int
: constant Boolean :=
2171 Is_Floating_Point_Type
(Expr_Type
)
2172 and then Is_Integer_Type
(Target_Type
);
2175 if not Overflow_Checks_Suppressed
(Target_Base
)
2176 and then not In_Subrange_Of
(Expr_Type
, Target_Base
, Conv_OK
)
2177 and then not Float_To_Int
2179 Set_Do_Overflow_Check
(N
);
2182 if not Range_Checks_Suppressed
(Target_Type
)
2183 and then not Range_Checks_Suppressed
(Expr_Type
)
2185 if Float_To_Int
then
2186 Apply_Float_Conversion_Check
(Expr
, Target_Type
);
2188 Apply_Scalar_Range_Check
2189 (Expr
, Target_Type
, Fixed_Int
=> Conv_OK
);
2194 elsif Comes_From_Source
(N
)
2195 and then Is_Record_Type
(Target_Type
)
2196 and then Is_Derived_Type
(Target_Type
)
2197 and then not Is_Tagged_Type
(Target_Type
)
2198 and then not Is_Constrained
(Target_Type
)
2199 and then Present
(Stored_Constraint
(Target_Type
))
2201 -- An unconstrained derived type may have inherited discriminant
2202 -- Build an actual discriminant constraint list using the stored
2203 -- constraint, to verify that the expression of the parent type
2204 -- satisfies the constraints imposed by the (unconstrained!)
2205 -- derived type. This applies to value conversions, not to view
2206 -- conversions of tagged types.
2209 Loc
: constant Source_Ptr
:= Sloc
(N
);
2211 Constraint
: Elmt_Id
;
2212 Discr_Value
: Node_Id
;
2215 New_Constraints
: constant Elist_Id
:= New_Elmt_List
;
2216 Old_Constraints
: constant Elist_Id
:=
2217 Discriminant_Constraint
(Expr_Type
);
2220 Constraint
:= First_Elmt
(Stored_Constraint
(Target_Type
));
2222 while Present
(Constraint
) loop
2223 Discr_Value
:= Node
(Constraint
);
2225 if Is_Entity_Name
(Discr_Value
)
2226 and then Ekind
(Entity
(Discr_Value
)) = E_Discriminant
2228 Discr
:= Corresponding_Discriminant
(Entity
(Discr_Value
));
2231 and then Scope
(Discr
) = Base_Type
(Expr_Type
)
2233 -- Parent is constrained by new discriminant. Obtain
2234 -- Value of original discriminant in expression. If
2235 -- the new discriminant has been used to constrain more
2236 -- than one of the stored discriminants, this will
2237 -- provide the required consistency check.
2240 Make_Selected_Component
(Loc
,
2242 Duplicate_Subexpr_No_Checks
2243 (Expr
, Name_Req
=> True),
2245 Make_Identifier
(Loc
, Chars
(Discr
))),
2249 -- Discriminant of more remote ancestor ???
2254 -- Derived type definition has an explicit value for
2255 -- this stored discriminant.
2259 (Duplicate_Subexpr_No_Checks
(Discr_Value
),
2263 Next_Elmt
(Constraint
);
2266 -- Use the unconstrained expression type to retrieve the
2267 -- discriminants of the parent, and apply momentarily the
2268 -- discriminant constraint synthesized above.
2270 Set_Discriminant_Constraint
(Expr_Type
, New_Constraints
);
2271 Cond
:= Build_Discriminant_Checks
(Expr
, Expr_Type
);
2272 Set_Discriminant_Constraint
(Expr_Type
, Old_Constraints
);
2275 Make_Raise_Constraint_Error
(Loc
,
2277 Reason
=> CE_Discriminant_Check_Failed
));
2280 -- For arrays, conversions are applied during expansion, to take
2281 -- into accounts changes of representation. The checks become range
2282 -- checks on the base type or length checks on the subtype, depending
2283 -- on whether the target type is unconstrained or constrained.
2288 end Apply_Type_Conversion_Checks
;
2290 ----------------------------------------------
2291 -- Apply_Universal_Integer_Attribute_Checks --
2292 ----------------------------------------------
2294 procedure Apply_Universal_Integer_Attribute_Checks
(N
: Node_Id
) is
2295 Loc
: constant Source_Ptr
:= Sloc
(N
);
2296 Typ
: constant Entity_Id
:= Etype
(N
);
2299 if Inside_A_Generic
then
2302 -- Nothing to do if checks are suppressed
2304 elsif Range_Checks_Suppressed
(Typ
)
2305 and then Overflow_Checks_Suppressed
(Typ
)
2309 -- Nothing to do if the attribute does not come from source. The
2310 -- internal attributes we generate of this type do not need checks,
2311 -- and furthermore the attempt to check them causes some circular
2312 -- elaboration orders when dealing with packed types.
2314 elsif not Comes_From_Source
(N
) then
2317 -- If the prefix is a selected component that depends on a discriminant
2318 -- the check may improperly expose a discriminant instead of using
2319 -- the bounds of the object itself. Set the type of the attribute to
2320 -- the base type of the context, so that a check will be imposed when
2321 -- needed (e.g. if the node appears as an index).
2323 elsif Nkind
(Prefix
(N
)) = N_Selected_Component
2324 and then Ekind
(Typ
) = E_Signed_Integer_Subtype
2325 and then Depends_On_Discriminant
(Scalar_Range
(Typ
))
2327 Set_Etype
(N
, Base_Type
(Typ
));
2329 -- Otherwise, replace the attribute node with a type conversion
2330 -- node whose expression is the attribute, retyped to universal
2331 -- integer, and whose subtype mark is the target type. The call
2332 -- to analyze this conversion will set range and overflow checks
2333 -- as required for proper detection of an out of range value.
2336 Set_Etype
(N
, Universal_Integer
);
2337 Set_Analyzed
(N
, True);
2340 Make_Type_Conversion
(Loc
,
2341 Subtype_Mark
=> New_Occurrence_Of
(Typ
, Loc
),
2342 Expression
=> Relocate_Node
(N
)));
2344 Analyze_And_Resolve
(N
, Typ
);
2348 end Apply_Universal_Integer_Attribute_Checks
;
2350 -------------------------------
2351 -- Build_Discriminant_Checks --
2352 -------------------------------
2354 function Build_Discriminant_Checks
2356 T_Typ
: Entity_Id
) return Node_Id
2358 Loc
: constant Source_Ptr
:= Sloc
(N
);
2361 Disc_Ent
: Entity_Id
;
2367 Disc
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
2369 -- For a fully private type, use the discriminants of the parent type
2371 if Is_Private_Type
(T_Typ
)
2372 and then No
(Full_View
(T_Typ
))
2374 Disc_Ent
:= First_Discriminant
(Etype
(Base_Type
(T_Typ
)));
2376 Disc_Ent
:= First_Discriminant
(T_Typ
);
2379 while Present
(Disc
) loop
2380 Dval
:= Node
(Disc
);
2382 if Nkind
(Dval
) = N_Identifier
2383 and then Ekind
(Entity
(Dval
)) = E_Discriminant
2385 Dval
:= New_Occurrence_Of
(Discriminal
(Entity
(Dval
)), Loc
);
2387 Dval
:= Duplicate_Subexpr_No_Checks
(Dval
);
2390 -- If we have an Unchecked_Union node, we can infer the discriminants
2393 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
2395 Get_Discriminant_Value
(
2396 First_Discriminant
(T_Typ
),
2398 Stored_Constraint
(T_Typ
)));
2402 Make_Selected_Component
(Loc
,
2404 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
2406 Make_Identifier
(Loc
, Chars
(Disc_Ent
)));
2408 Set_Is_In_Discriminant_Check
(Dref
);
2411 Evolve_Or_Else
(Cond
,
2414 Right_Opnd
=> Dval
));
2417 Next_Discriminant
(Disc_Ent
);
2421 end Build_Discriminant_Checks
;
2423 -----------------------------------
2424 -- Check_Valid_Lvalue_Subscripts --
2425 -----------------------------------
2427 procedure Check_Valid_Lvalue_Subscripts
(Expr
: Node_Id
) is
2429 -- Skip this if range checks are suppressed
2431 if Range_Checks_Suppressed
(Etype
(Expr
)) then
2434 -- Only do this check for expressions that come from source. We
2435 -- assume that expander generated assignments explicitly include
2436 -- any necessary checks. Note that this is not just an optimization,
2437 -- it avoids infinite recursions!
2439 elsif not Comes_From_Source
(Expr
) then
2442 -- For a selected component, check the prefix
2444 elsif Nkind
(Expr
) = N_Selected_Component
then
2445 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
2448 -- Case of indexed component
2450 elsif Nkind
(Expr
) = N_Indexed_Component
then
2451 Apply_Subscript_Validity_Checks
(Expr
);
2453 -- Prefix may itself be or contain an indexed component, and
2454 -- these subscripts need checking as well
2456 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
2458 end Check_Valid_Lvalue_Subscripts
;
2460 ----------------------------------
2461 -- Null_Exclusion_Static_Checks --
2462 ----------------------------------
2464 procedure Null_Exclusion_Static_Checks
(N
: Node_Id
) is
2465 K
: constant Node_Kind
:= Nkind
(N
);
2467 Related_Nod
: Node_Id
;
2468 Has_Null_Exclusion
: Boolean := False;
2470 type Msg_Kind
is (Components
, Formals
, Objects
);
2471 Msg_K
: Msg_Kind
:= Objects
;
2472 -- Used by local subprograms to generate precise error messages
2474 procedure Check_Must_Be_Access
2476 Has_Null_Exclusion
: Boolean);
2477 -- ??? local subprograms must have comment on spec
2479 procedure Check_Already_Null_Excluding_Type
2481 Has_Null_Exclusion
: Boolean;
2482 Related_Nod
: Node_Id
);
2483 -- ??? local subprograms must have comment on spec
2485 procedure Check_Must_Be_Initialized
2487 Related_Nod
: Node_Id
);
2488 -- ??? local subprograms must have comment on spec
2490 procedure Check_Null_Not_Allowed
(N
: Node_Id
);
2491 -- ??? local subprograms must have comment on spec
2493 -- ??? following bodies lack comments
2495 --------------------------
2496 -- Check_Must_Be_Access --
2497 --------------------------
2499 procedure Check_Must_Be_Access
2501 Has_Null_Exclusion
: Boolean)
2504 if Has_Null_Exclusion
2505 and then not Is_Access_Type
(Typ
)
2507 Error_Msg_N
("(Ada 2005) must be an access type", Related_Nod
);
2509 end Check_Must_Be_Access
;
2511 ---------------------------------------
2512 -- Check_Already_Null_Excluding_Type --
2513 ---------------------------------------
2515 procedure Check_Already_Null_Excluding_Type
2517 Has_Null_Exclusion
: Boolean;
2518 Related_Nod
: Node_Id
)
2521 if Has_Null_Exclusion
2522 and then Can_Never_Be_Null
(Typ
)
2525 ("(Ada 2005) already a null-excluding type", Related_Nod
);
2527 end Check_Already_Null_Excluding_Type
;
2529 -------------------------------
2530 -- Check_Must_Be_Initialized --
2531 -------------------------------
2533 procedure Check_Must_Be_Initialized
2535 Related_Nod
: Node_Id
)
2537 Expr
: constant Node_Id
:= Expression
(N
);
2540 pragma Assert
(Nkind
(N
) = N_Component_Declaration
2541 or else Nkind
(N
) = N_Object_Declaration
);
2543 if not Present
(Expr
) then
2547 ("(Ada 2005) null-excluding components must be " &
2548 "initialized", Related_Nod
);
2552 ("(Ada 2005) null-excluding formals must be initialized",
2557 ("(Ada 2005) null-excluding objects must be initialized",
2561 end Check_Must_Be_Initialized
;
2563 ----------------------------
2564 -- Check_Null_Not_Allowed --
2565 ----------------------------
2567 procedure Check_Null_Not_Allowed
(N
: Node_Id
) is
2568 Expr
: constant Node_Id
:= Expression
(N
);
2572 and then Nkind
(Expr
) = N_Null
2576 Apply_Compile_Time_Constraint_Error
2578 Msg
=> "(Ada 2005) NULL not allowed in"
2579 & " null-excluding components?",
2580 Reason
=> CE_Null_Not_Allowed
,
2584 Apply_Compile_Time_Constraint_Error
2586 Msg
=> "(Ada 2005) NULL not allowed in"
2587 & " null-excluding formals?",
2588 Reason
=> CE_Null_Not_Allowed
,
2592 Apply_Compile_Time_Constraint_Error
2594 Msg
=> "(Ada 2005) NULL not allowed in"
2595 & " null-excluding objects?",
2596 Reason
=> CE_Null_Not_Allowed
,
2600 end Check_Null_Not_Allowed
;
2602 -- Start of processing for Null_Exclusion_Static_Checks
2605 pragma Assert
(K
= N_Component_Declaration
2606 or else K
= N_Parameter_Specification
2607 or else K
= N_Object_Declaration
2608 or else K
= N_Discriminant_Specification
2609 or else K
= N_Allocator
);
2612 when N_Component_Declaration
=>
2613 Msg_K
:= Components
;
2615 if not Present
(Access_Definition
(Component_Definition
(N
))) then
2616 Has_Null_Exclusion
:= Null_Exclusion_Present
2617 (Component_Definition
(N
));
2618 Typ
:= Etype
(Subtype_Indication
(Component_Definition
(N
)));
2619 Related_Nod
:= Subtype_Indication
(Component_Definition
(N
));
2620 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2621 Check_Already_Null_Excluding_Type
2622 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2623 Check_Must_Be_Initialized
(N
, Related_Nod
);
2626 Check_Null_Not_Allowed
(N
);
2628 when N_Parameter_Specification
=>
2630 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2631 Typ
:= Entity
(Parameter_Type
(N
));
2632 Related_Nod
:= Parameter_Type
(N
);
2633 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2634 Check_Already_Null_Excluding_Type
2635 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2636 Check_Null_Not_Allowed
(N
);
2638 when N_Object_Declaration
=>
2640 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2641 Typ
:= Entity
(Object_Definition
(N
));
2642 Related_Nod
:= Object_Definition
(N
);
2643 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2644 Check_Already_Null_Excluding_Type
2645 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2646 Check_Must_Be_Initialized
(N
, Related_Nod
);
2647 Check_Null_Not_Allowed
(N
);
2649 when N_Discriminant_Specification
=>
2650 Msg_K
:= Components
;
2652 if Nkind
(Discriminant_Type
(N
)) /= N_Access_Definition
then
2653 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2654 Typ
:= Etype
(Defining_Identifier
(N
));
2655 Related_Nod
:= Discriminant_Type
(N
);
2656 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2657 Check_Already_Null_Excluding_Type
2658 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2661 Check_Null_Not_Allowed
(N
);
2665 Has_Null_Exclusion
:= Null_Exclusion_Present
(N
);
2666 Typ
:= Etype
(Expression
(N
));
2668 if Nkind
(Expression
(N
)) = N_Qualified_Expression
then
2669 Related_Nod
:= Subtype_Mark
(Expression
(N
));
2671 Related_Nod
:= Expression
(N
);
2674 Check_Must_Be_Access
(Typ
, Has_Null_Exclusion
);
2675 Check_Already_Null_Excluding_Type
2676 (Typ
, Has_Null_Exclusion
, Related_Nod
);
2677 Check_Null_Not_Allowed
(N
);
2680 raise Program_Error
;
2682 end Null_Exclusion_Static_Checks
;
2684 ----------------------------------
2685 -- Conditional_Statements_Begin --
2686 ----------------------------------
2688 procedure Conditional_Statements_Begin
is
2690 Saved_Checks_TOS
:= Saved_Checks_TOS
+ 1;
2692 -- If stack overflows, kill all checks, that way we know to
2693 -- simply reset the number of saved checks to zero on return.
2694 -- This should never occur in practice.
2696 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
2699 -- In the normal case, we just make a new stack entry saving
2700 -- the current number of saved checks for a later restore.
2703 Saved_Checks_Stack
(Saved_Checks_TOS
) := Num_Saved_Checks
;
2705 if Debug_Flag_CC
then
2706 w
("Conditional_Statements_Begin: Num_Saved_Checks = ",
2710 end Conditional_Statements_Begin
;
2712 --------------------------------
2713 -- Conditional_Statements_End --
2714 --------------------------------
2716 procedure Conditional_Statements_End
is
2718 pragma Assert
(Saved_Checks_TOS
> 0);
2720 -- If the saved checks stack overflowed, then we killed all
2721 -- checks, so setting the number of saved checks back to
2722 -- zero is correct. This should never occur in practice.
2724 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
2725 Num_Saved_Checks
:= 0;
2727 -- In the normal case, restore the number of saved checks
2728 -- from the top stack entry.
2731 Num_Saved_Checks
:= Saved_Checks_Stack
(Saved_Checks_TOS
);
2732 if Debug_Flag_CC
then
2733 w
("Conditional_Statements_End: Num_Saved_Checks = ",
2738 Saved_Checks_TOS
:= Saved_Checks_TOS
- 1;
2739 end Conditional_Statements_End
;
2741 ---------------------
2742 -- Determine_Range --
2743 ---------------------
2745 Cache_Size
: constant := 2 ** 10;
2746 type Cache_Index
is range 0 .. Cache_Size
- 1;
2747 -- Determine size of below cache (power of 2 is more efficient!)
2749 Determine_Range_Cache_N
: array (Cache_Index
) of Node_Id
;
2750 Determine_Range_Cache_Lo
: array (Cache_Index
) of Uint
;
2751 Determine_Range_Cache_Hi
: array (Cache_Index
) of Uint
;
2752 -- The above arrays are used to implement a small direct cache
2753 -- for Determine_Range calls. Because of the way Determine_Range
2754 -- recursively traces subexpressions, and because overflow checking
2755 -- calls the routine on the way up the tree, a quadratic behavior
2756 -- can otherwise be encountered in large expressions. The cache
2757 -- entry for node N is stored in the (N mod Cache_Size) entry, and
2758 -- can be validated by checking the actual node value stored there.
2760 procedure Determine_Range
2766 Typ
: constant Entity_Id
:= Etype
(N
);
2770 -- Lo and Hi bounds of left operand
2774 -- Lo and Hi bounds of right (or only) operand
2777 -- Temp variable used to hold a bound node
2780 -- High bound of base type of expression
2784 -- Refined values for low and high bounds, after tightening
2787 -- Used in lower level calls to indicate if call succeeded
2789 Cindex
: Cache_Index
;
2790 -- Used to search cache
2792 function OK_Operands
return Boolean;
2793 -- Used for binary operators. Determines the ranges of the left and
2794 -- right operands, and if they are both OK, returns True, and puts
2795 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left
2801 function OK_Operands
return Boolean is
2803 Determine_Range
(Left_Opnd
(N
), OK1
, Lo_Left
, Hi_Left
);
2809 Determine_Range
(Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
);
2813 -- Start of processing for Determine_Range
2816 -- Prevent junk warnings by initializing range variables
2823 -- If the type is not discrete, or is undefined, then we can't
2824 -- do anything about determining the range.
2826 if No
(Typ
) or else not Is_Discrete_Type
(Typ
)
2827 or else Error_Posted
(N
)
2833 -- For all other cases, we can determine the range
2837 -- If value is compile time known, then the possible range is the
2838 -- one value that we know this expression definitely has!
2840 if Compile_Time_Known_Value
(N
) then
2841 Lo
:= Expr_Value
(N
);
2846 -- Return if already in the cache
2848 Cindex
:= Cache_Index
(N
mod Cache_Size
);
2850 if Determine_Range_Cache_N
(Cindex
) = N
then
2851 Lo
:= Determine_Range_Cache_Lo
(Cindex
);
2852 Hi
:= Determine_Range_Cache_Hi
(Cindex
);
2856 -- Otherwise, start by finding the bounds of the type of the
2857 -- expression, the value cannot be outside this range (if it
2858 -- is, then we have an overflow situation, which is a separate
2859 -- check, we are talking here only about the expression value).
2861 -- We use the actual bound unless it is dynamic, in which case
2862 -- use the corresponding base type bound if possible. If we can't
2863 -- get a bound then we figure we can't determine the range (a
2864 -- peculiar case, that perhaps cannot happen, but there is no
2865 -- point in bombing in this optimization circuit.
2867 -- First the low bound
2869 Bound
:= Type_Low_Bound
(Typ
);
2871 if Compile_Time_Known_Value
(Bound
) then
2872 Lo
:= Expr_Value
(Bound
);
2874 elsif Compile_Time_Known_Value
(Type_Low_Bound
(Base_Type
(Typ
))) then
2875 Lo
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
2882 -- Now the high bound
2884 Bound
:= Type_High_Bound
(Typ
);
2886 -- We need the high bound of the base type later on, and this should
2887 -- always be compile time known. Again, it is not clear that this
2888 -- can ever be false, but no point in bombing.
2890 if Compile_Time_Known_Value
(Type_High_Bound
(Base_Type
(Typ
))) then
2891 Hbound
:= Expr_Value
(Type_High_Bound
(Base_Type
(Typ
)));
2899 -- If we have a static subtype, then that may have a tighter bound
2900 -- so use the upper bound of the subtype instead in this case.
2902 if Compile_Time_Known_Value
(Bound
) then
2903 Hi
:= Expr_Value
(Bound
);
2906 -- We may be able to refine this value in certain situations. If
2907 -- refinement is possible, then Lor and Hir are set to possibly
2908 -- tighter bounds, and OK1 is set to True.
2912 -- For unary plus, result is limited by range of operand
2915 Determine_Range
(Right_Opnd
(N
), OK1
, Lor
, Hir
);
2917 -- For unary minus, determine range of operand, and negate it
2920 Determine_Range
(Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
);
2927 -- For binary addition, get range of each operand and do the
2928 -- addition to get the result range.
2932 Lor
:= Lo_Left
+ Lo_Right
;
2933 Hir
:= Hi_Left
+ Hi_Right
;
2936 -- Division is tricky. The only case we consider is where the
2937 -- right operand is a positive constant, and in this case we
2938 -- simply divide the bounds of the left operand
2942 if Lo_Right
= Hi_Right
2943 and then Lo_Right
> 0
2945 Lor
:= Lo_Left
/ Lo_Right
;
2946 Hir
:= Hi_Left
/ Lo_Right
;
2953 -- For binary subtraction, get range of each operand and do
2954 -- the worst case subtraction to get the result range.
2956 when N_Op_Subtract
=>
2958 Lor
:= Lo_Left
- Hi_Right
;
2959 Hir
:= Hi_Left
- Lo_Right
;
2962 -- For MOD, if right operand is a positive constant, then
2963 -- result must be in the allowable range of mod results.
2967 if Lo_Right
= Hi_Right
2968 and then Lo_Right
/= 0
2970 if Lo_Right
> 0 then
2972 Hir
:= Lo_Right
- 1;
2974 else -- Lo_Right < 0
2975 Lor
:= Lo_Right
+ 1;
2984 -- For REM, if right operand is a positive constant, then
2985 -- result must be in the allowable range of mod results.
2989 if Lo_Right
= Hi_Right
2990 and then Lo_Right
/= 0
2993 Dval
: constant Uint
:= (abs Lo_Right
) - 1;
2996 -- The sign of the result depends on the sign of the
2997 -- dividend (but not on the sign of the divisor, hence
2998 -- the abs operation above).
3018 -- Attribute reference cases
3020 when N_Attribute_Reference
=>
3021 case Attribute_Name
(N
) is
3023 -- For Pos/Val attributes, we can refine the range using the
3024 -- possible range of values of the attribute expression
3026 when Name_Pos | Name_Val
=>
3027 Determine_Range
(First
(Expressions
(N
)), OK1
, Lor
, Hir
);
3029 -- For Length attribute, use the bounds of the corresponding
3030 -- index type to refine the range.
3034 Atyp
: Entity_Id
:= Etype
(Prefix
(N
));
3042 if Is_Access_Type
(Atyp
) then
3043 Atyp
:= Designated_Type
(Atyp
);
3046 -- For string literal, we know exact value
3048 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
3050 Lo
:= String_Literal_Length
(Atyp
);
3051 Hi
:= String_Literal_Length
(Atyp
);
3055 -- Otherwise check for expression given
3057 if No
(Expressions
(N
)) then
3061 UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
3064 Indx
:= First_Index
(Atyp
);
3065 for J
in 2 .. Inum
loop
3066 Indx
:= Next_Index
(Indx
);
3070 (Type_Low_Bound
(Etype
(Indx
)), OK1
, LL
, LU
);
3074 (Type_High_Bound
(Etype
(Indx
)), OK1
, UL
, UU
);
3078 -- The maximum value for Length is the biggest
3079 -- possible gap between the values of the bounds.
3080 -- But of course, this value cannot be negative.
3082 Hir
:= UI_Max
(Uint_0
, UU
- LL
);
3084 -- For constrained arrays, the minimum value for
3085 -- Length is taken from the actual value of the
3086 -- bounds, since the index will be exactly of
3089 if Is_Constrained
(Atyp
) then
3090 Lor
:= UI_Max
(Uint_0
, UL
- LU
);
3092 -- For an unconstrained array, the minimum value
3093 -- for length is always zero.
3102 -- No special handling for other attributes
3103 -- Probably more opportunities exist here ???
3110 -- For type conversion from one discrete type to another, we
3111 -- can refine the range using the converted value.
3113 when N_Type_Conversion
=>
3114 Determine_Range
(Expression
(N
), OK1
, Lor
, Hir
);
3116 -- Nothing special to do for all other expression kinds
3124 -- At this stage, if OK1 is true, then we know that the actual
3125 -- result of the computed expression is in the range Lor .. Hir.
3126 -- We can use this to restrict the possible range of results.
3130 -- If the refined value of the low bound is greater than the
3131 -- type high bound, then reset it to the more restrictive
3132 -- value. However, we do NOT do this for the case of a modular
3133 -- type where the possible upper bound on the value is above the
3134 -- base type high bound, because that means the result could wrap.
3137 and then not (Is_Modular_Integer_Type
(Typ
)
3138 and then Hir
> Hbound
)
3143 -- Similarly, if the refined value of the high bound is less
3144 -- than the value so far, then reset it to the more restrictive
3145 -- value. Again, we do not do this if the refined low bound is
3146 -- negative for a modular type, since this would wrap.
3149 and then not (Is_Modular_Integer_Type
(Typ
)
3150 and then Lor
< Uint_0
)
3156 -- Set cache entry for future call and we are all done
3158 Determine_Range_Cache_N
(Cindex
) := N
;
3159 Determine_Range_Cache_Lo
(Cindex
) := Lo
;
3160 Determine_Range_Cache_Hi
(Cindex
) := Hi
;
3163 -- If any exception occurs, it means that we have some bug in the compiler
3164 -- possibly triggered by a previous error, or by some unforseen peculiar
3165 -- occurrence. However, this is only an optimization attempt, so there is
3166 -- really no point in crashing the compiler. Instead we just decide, too
3167 -- bad, we can't figure out a range in this case after all.
3172 -- Debug flag K disables this behavior (useful for debugging)
3174 if Debug_Flag_K
then
3182 end Determine_Range
;
3184 ------------------------------------
3185 -- Discriminant_Checks_Suppressed --
3186 ------------------------------------
3188 function Discriminant_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3191 if Is_Unchecked_Union
(E
) then
3193 elsif Checks_May_Be_Suppressed
(E
) then
3194 return Is_Check_Suppressed
(E
, Discriminant_Check
);
3198 return Scope_Suppress
(Discriminant_Check
);
3199 end Discriminant_Checks_Suppressed
;
3201 --------------------------------
3202 -- Division_Checks_Suppressed --
3203 --------------------------------
3205 function Division_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3207 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
3208 return Is_Check_Suppressed
(E
, Division_Check
);
3210 return Scope_Suppress
(Division_Check
);
3212 end Division_Checks_Suppressed
;
3214 -----------------------------------
3215 -- Elaboration_Checks_Suppressed --
3216 -----------------------------------
3218 function Elaboration_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
3221 if Kill_Elaboration_Checks
(E
) then
3223 elsif Checks_May_Be_Suppressed
(E
) then
3224 return Is_Check_Suppressed
(E
, Elaboration_Check
);
3228 return Scope_Suppress
(Elaboration_Check
);
3229 end Elaboration_Checks_Suppressed
;
3231 ---------------------------
3232 -- Enable_Overflow_Check --
3233 ---------------------------
3235 procedure Enable_Overflow_Check
(N
: Node_Id
) is
3236 Typ
: constant Entity_Id
:= Base_Type
(Etype
(N
));
3245 if Debug_Flag_CC
then
3246 w
("Enable_Overflow_Check for node ", Int
(N
));
3247 Write_Str
(" Source location = ");
3252 -- Nothing to do if the range of the result is known OK. We skip
3253 -- this for conversions, since the caller already did the check,
3254 -- and in any case the condition for deleting the check for a
3255 -- type conversion is different in any case.
3257 if Nkind
(N
) /= N_Type_Conversion
then
3258 Determine_Range
(N
, OK
, Lo
, Hi
);
3260 -- Note in the test below that we assume that if a bound of the
3261 -- range is equal to that of the type. That's not quite accurate
3262 -- but we do this for the following reasons:
3264 -- a) The way that Determine_Range works, it will typically report
3265 -- the bounds of the value as being equal to the bounds of the
3266 -- type, because it either can't tell anything more precise, or
3267 -- does not think it is worth the effort to be more precise.
3269 -- b) It is very unusual to have a situation in which this would
3270 -- generate an unnecessary overflow check (an example would be
3271 -- a subtype with a range 0 .. Integer'Last - 1 to which the
3272 -- literal value one is added.
3274 -- c) The alternative is a lot of special casing in this routine
3275 -- which would partially duplicate Determine_Range processing.
3278 and then Lo
> Expr_Value
(Type_Low_Bound
(Typ
))
3279 and then Hi
< Expr_Value
(Type_High_Bound
(Typ
))
3281 if Debug_Flag_CC
then
3282 w
("No overflow check required");
3289 -- If not in optimizing mode, set flag and we are done. We are also
3290 -- done (and just set the flag) if the type is not a discrete type,
3291 -- since it is not worth the effort to eliminate checks for other
3292 -- than discrete types. In addition, we take this same path if we
3293 -- have stored the maximum number of checks possible already (a
3294 -- very unlikely situation, but we do not want to blow up!)
3296 if Optimization_Level
= 0
3297 or else not Is_Discrete_Type
(Etype
(N
))
3298 or else Num_Saved_Checks
= Saved_Checks
'Last
3300 Set_Do_Overflow_Check
(N
, True);
3302 if Debug_Flag_CC
then
3303 w
("Optimization off");
3309 -- Otherwise evaluate and check the expression
3314 Target_Type
=> Empty
,
3320 if Debug_Flag_CC
then
3321 w
("Called Find_Check");
3325 w
(" Check_Num = ", Chk
);
3326 w
(" Ent = ", Int
(Ent
));
3327 Write_Str
(" Ofs = ");
3332 -- If check is not of form to optimize, then set flag and we are done
3335 Set_Do_Overflow_Check
(N
, True);
3339 -- If check is already performed, then return without setting flag
3342 if Debug_Flag_CC
then
3343 w
("Check suppressed!");
3349 -- Here we will make a new entry for the new check
3351 Set_Do_Overflow_Check
(N
, True);
3352 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
3353 Saved_Checks
(Num_Saved_Checks
) :=
3358 Target_Type
=> Empty
);
3360 if Debug_Flag_CC
then
3361 w
("Make new entry, check number = ", Num_Saved_Checks
);
3362 w
(" Entity = ", Int
(Ent
));
3363 Write_Str
(" Offset = ");
3365 w
(" Check_Type = O");
3366 w
(" Target_Type = Empty");
3369 -- If we get an exception, then something went wrong, probably because
3370 -- of an error in the structure of the tree due to an incorrect program.
3371 -- Or it may be a bug in the optimization circuit. In either case the
3372 -- safest thing is simply to set the check flag unconditionally.
3376 Set_Do_Overflow_Check
(N
, True);
3378 if Debug_Flag_CC
then
3379 w
(" exception occurred, overflow flag set");
3383 end Enable_Overflow_Check
;
3385 ------------------------
3386 -- Enable_Range_Check --
3387 ------------------------
3389 procedure Enable_Range_Check
(N
: Node_Id
) is
3398 -- Return if unchecked type conversion with range check killed.
3399 -- In this case we never set the flag (that's what Kill_Range_Check
3402 if Nkind
(N
) = N_Unchecked_Type_Conversion
3403 and then Kill_Range_Check
(N
)
3408 -- Debug trace output
3410 if Debug_Flag_CC
then
3411 w
("Enable_Range_Check for node ", Int
(N
));
3412 Write_Str
(" Source location = ");
3417 -- If not in optimizing mode, set flag and we are done. We are also
3418 -- done (and just set the flag) if the type is not a discrete type,
3419 -- since it is not worth the effort to eliminate checks for other
3420 -- than discrete types. In addition, we take this same path if we
3421 -- have stored the maximum number of checks possible already (a
3422 -- very unlikely situation, but we do not want to blow up!)
3424 if Optimization_Level
= 0
3425 or else No
(Etype
(N
))
3426 or else not Is_Discrete_Type
(Etype
(N
))
3427 or else Num_Saved_Checks
= Saved_Checks
'Last
3429 Set_Do_Range_Check
(N
, True);
3431 if Debug_Flag_CC
then
3432 w
("Optimization off");
3438 -- Otherwise find out the target type
3442 -- For assignment, use left side subtype
3444 if Nkind
(P
) = N_Assignment_Statement
3445 and then Expression
(P
) = N
3447 Ttyp
:= Etype
(Name
(P
));
3449 -- For indexed component, use subscript subtype
3451 elsif Nkind
(P
) = N_Indexed_Component
then
3458 Atyp
:= Etype
(Prefix
(P
));
3460 if Is_Access_Type
(Atyp
) then
3461 Atyp
:= Designated_Type
(Atyp
);
3463 -- If the prefix is an access to an unconstrained array,
3464 -- perform check unconditionally: it depends on the bounds
3465 -- of an object and we cannot currently recognize whether
3466 -- the test may be redundant.
3468 if not Is_Constrained
(Atyp
) then
3469 Set_Do_Range_Check
(N
, True);
3473 -- Ditto if the prefix is an explicit dereference whose
3474 -- designated type is unconstrained.
3476 elsif Nkind
(Prefix
(P
)) = N_Explicit_Dereference
3477 and then not Is_Constrained
(Atyp
)
3479 Set_Do_Range_Check
(N
, True);
3483 Indx
:= First_Index
(Atyp
);
3484 Subs
:= First
(Expressions
(P
));
3487 Ttyp
:= Etype
(Indx
);
3496 -- For now, ignore all other cases, they are not so interesting
3499 if Debug_Flag_CC
then
3500 w
(" target type not found, flag set");
3503 Set_Do_Range_Check
(N
, True);
3507 -- Evaluate and check the expression
3512 Target_Type
=> Ttyp
,
3518 if Debug_Flag_CC
then
3519 w
("Called Find_Check");
3520 w
("Target_Typ = ", Int
(Ttyp
));
3524 w
(" Check_Num = ", Chk
);
3525 w
(" Ent = ", Int
(Ent
));
3526 Write_Str
(" Ofs = ");
3531 -- If check is not of form to optimize, then set flag and we are done
3534 if Debug_Flag_CC
then
3535 w
(" expression not of optimizable type, flag set");
3538 Set_Do_Range_Check
(N
, True);
3542 -- If check is already performed, then return without setting flag
3545 if Debug_Flag_CC
then
3546 w
("Check suppressed!");
3552 -- Here we will make a new entry for the new check
3554 Set_Do_Range_Check
(N
, True);
3555 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
3556 Saved_Checks
(Num_Saved_Checks
) :=
3561 Target_Type
=> Ttyp
);
3563 if Debug_Flag_CC
then
3564 w
("Make new entry, check number = ", Num_Saved_Checks
);
3565 w
(" Entity = ", Int
(Ent
));
3566 Write_Str
(" Offset = ");
3568 w
(" Check_Type = R");
3569 w
(" Target_Type = ", Int
(Ttyp
));
3573 -- If we get an exception, then something went wrong, probably because
3574 -- of an error in the structure of the tree due to an incorrect program.
3575 -- Or it may be a bug in the optimization circuit. In either case the
3576 -- safest thing is simply to set the check flag unconditionally.
3580 Set_Do_Range_Check
(N
, True);
3582 if Debug_Flag_CC
then
3583 w
(" exception occurred, range flag set");
3587 end Enable_Range_Check
;
3593 procedure Ensure_Valid
(Expr
: Node_Id
; Holes_OK
: Boolean := False) is
3594 Typ
: constant Entity_Id
:= Etype
(Expr
);
3597 -- Ignore call if we are not doing any validity checking
3599 if not Validity_Checks_On
then
3602 -- Ignore call if range checks suppressed on entity in question
3604 elsif Is_Entity_Name
(Expr
)
3605 and then Range_Checks_Suppressed
(Entity
(Expr
))
3609 -- No check required if expression is from the expander, we assume
3610 -- the expander will generate whatever checks are needed. Note that
3611 -- this is not just an optimization, it avoids infinite recursions!
3613 -- Unchecked conversions must be checked, unless they are initialized
3614 -- scalar values, as in a component assignment in an init proc.
3616 -- In addition, we force a check if Force_Validity_Checks is set
3618 elsif not Comes_From_Source
(Expr
)
3619 and then not Force_Validity_Checks
3620 and then (Nkind
(Expr
) /= N_Unchecked_Type_Conversion
3621 or else Kill_Range_Check
(Expr
))
3625 -- No check required if expression is known to have valid value
3627 elsif Expr_Known_Valid
(Expr
) then
3630 -- No check required if checks off
3632 elsif Range_Checks_Suppressed
(Typ
) then
3635 -- Ignore case of enumeration with holes where the flag is set not
3636 -- to worry about holes, since no special validity check is needed
3638 elsif Is_Enumeration_Type
(Typ
)
3639 and then Has_Non_Standard_Rep
(Typ
)
3644 -- No check required on the left-hand side of an assignment
3646 elsif Nkind
(Parent
(Expr
)) = N_Assignment_Statement
3647 and then Expr
= Name
(Parent
(Expr
))
3651 -- An annoying special case. If this is an out parameter of a scalar
3652 -- type, then the value is not going to be accessed, therefore it is
3653 -- inappropriate to do any validity check at the call site.
3656 -- Only need to worry about scalar types
3658 if Is_Scalar_Type
(Typ
) then
3668 -- Find actual argument (which may be a parameter association)
3669 -- and the parent of the actual argument (the call statement)
3674 if Nkind
(P
) = N_Parameter_Association
then
3679 -- Only need to worry if we are argument of a procedure
3680 -- call since functions don't have out parameters. If this
3681 -- is an indirect or dispatching call, get signature from
3682 -- the subprogram type.
3684 if Nkind
(P
) = N_Procedure_Call_Statement
then
3685 L
:= Parameter_Associations
(P
);
3687 if Is_Entity_Name
(Name
(P
)) then
3688 E
:= Entity
(Name
(P
));
3690 pragma Assert
(Nkind
(Name
(P
)) = N_Explicit_Dereference
);
3691 E
:= Etype
(Name
(P
));
3694 -- Only need to worry if there are indeed actuals, and
3695 -- if this could be a procedure call, otherwise we cannot
3696 -- get a match (either we are not an argument, or the
3697 -- mode of the formal is not OUT). This test also filters
3698 -- out the generic case.
3700 if Is_Non_Empty_List
(L
)
3701 and then Is_Subprogram
(E
)
3703 -- This is the loop through parameters, looking to
3704 -- see if there is an OUT parameter for which we are
3707 F
:= First_Formal
(E
);
3710 while Present
(F
) loop
3711 if Ekind
(F
) = E_Out_Parameter
and then A
= N
then
3724 -- If we fall through, a validity check is required. Note that it would
3725 -- not be good to set Do_Range_Check, even in contexts where this is
3726 -- permissible, since this flag causes checking against the target type,
3727 -- not the source type in contexts such as assignments
3729 Insert_Valid_Check
(Expr
);
3732 ----------------------
3733 -- Expr_Known_Valid --
3734 ----------------------
3736 function Expr_Known_Valid
(Expr
: Node_Id
) return Boolean is
3737 Typ
: constant Entity_Id
:= Etype
(Expr
);
3740 -- Non-scalar types are always considered valid, since they never
3741 -- give rise to the issues of erroneous or bounded error behavior
3742 -- that are the concern. In formal reference manual terms the
3743 -- notion of validity only applies to scalar types. Note that
3744 -- even when packed arrays are represented using modular types,
3745 -- they are still arrays semantically, so they are also always
3746 -- valid (in particular, the unused bits can be random rubbish
3747 -- without affecting the validity of the array value).
3749 if not Is_Scalar_Type
(Typ
) or else Is_Packed_Array_Type
(Typ
) then
3752 -- If no validity checking, then everything is considered valid
3754 elsif not Validity_Checks_On
then
3757 -- Floating-point types are considered valid unless floating-point
3758 -- validity checks have been specifically turned on.
3760 elsif Is_Floating_Point_Type
(Typ
)
3761 and then not Validity_Check_Floating_Point
3765 -- If the expression is the value of an object that is known to
3766 -- be valid, then clearly the expression value itself is valid.
3768 elsif Is_Entity_Name
(Expr
)
3769 and then Is_Known_Valid
(Entity
(Expr
))
3773 -- If the type is one for which all values are known valid, then
3774 -- we are sure that the value is valid except in the slightly odd
3775 -- case where the expression is a reference to a variable whose size
3776 -- has been explicitly set to a value greater than the object size.
3778 elsif Is_Known_Valid
(Typ
) then
3779 if Is_Entity_Name
(Expr
)
3780 and then Ekind
(Entity
(Expr
)) = E_Variable
3781 and then Esize
(Entity
(Expr
)) > Esize
(Typ
)
3788 -- Integer and character literals always have valid values, where
3789 -- appropriate these will be range checked in any case.
3791 elsif Nkind
(Expr
) = N_Integer_Literal
3793 Nkind
(Expr
) = N_Character_Literal
3797 -- If we have a type conversion or a qualification of a known valid
3798 -- value, then the result will always be valid.
3800 elsif Nkind
(Expr
) = N_Type_Conversion
3802 Nkind
(Expr
) = N_Qualified_Expression
3804 return Expr_Known_Valid
(Expression
(Expr
));
3806 -- The result of any function call or operator is always considered
3807 -- valid, since we assume the necessary checks are done by the call.
3808 -- For operators on floating-point operations, we must also check
3809 -- when the operation is the right-hand side of an assignment, or
3810 -- is an actual in a call.
3813 Nkind
(Expr
) in N_Binary_Op
or else Nkind
(Expr
) in N_Unary_Op
3815 if Is_Floating_Point_Type
(Typ
)
3816 and then Validity_Check_Floating_Point
3818 (Nkind
(Parent
(Expr
)) = N_Assignment_Statement
3819 or else Nkind
(Parent
(Expr
)) = N_Function_Call
3820 or else Nkind
(Parent
(Expr
)) = N_Parameter_Association
)
3827 elsif Nkind
(Expr
) = N_Function_Call
then
3830 -- For all other cases, we do not know the expression is valid
3835 end Expr_Known_Valid
;
3841 procedure Find_Check
3843 Check_Type
: Character;
3844 Target_Type
: Entity_Id
;
3845 Entry_OK
: out Boolean;
3846 Check_Num
: out Nat
;
3847 Ent
: out Entity_Id
;
3850 function Within_Range_Of
3851 (Target_Type
: Entity_Id
;
3852 Check_Type
: Entity_Id
) return Boolean;
3853 -- Given a requirement for checking a range against Target_Type, and
3854 -- and a range Check_Type against which a check has already been made,
3855 -- determines if the check against check type is sufficient to ensure
3856 -- that no check against Target_Type is required.
3858 ---------------------
3859 -- Within_Range_Of --
3860 ---------------------
3862 function Within_Range_Of
3863 (Target_Type
: Entity_Id
;
3864 Check_Type
: Entity_Id
) return Boolean
3867 if Target_Type
= Check_Type
then
3872 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Type
);
3873 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Type
);
3874 Clo
: constant Node_Id
:= Type_Low_Bound
(Check_Type
);
3875 Chi
: constant Node_Id
:= Type_High_Bound
(Check_Type
);
3879 or else (Compile_Time_Known_Value
(Tlo
)
3881 Compile_Time_Known_Value
(Clo
)
3883 Expr_Value
(Clo
) >= Expr_Value
(Tlo
)))
3886 or else (Compile_Time_Known_Value
(Thi
)
3888 Compile_Time_Known_Value
(Chi
)
3890 Expr_Value
(Chi
) <= Expr_Value
(Clo
)))
3898 end Within_Range_Of
;
3900 -- Start of processing for Find_Check
3903 -- Establish default, to avoid warnings from GCC
3907 -- Case of expression is simple entity reference
3909 if Is_Entity_Name
(Expr
) then
3910 Ent
:= Entity
(Expr
);
3913 -- Case of expression is entity + known constant
3915 elsif Nkind
(Expr
) = N_Op_Add
3916 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
3917 and then Is_Entity_Name
(Left_Opnd
(Expr
))
3919 Ent
:= Entity
(Left_Opnd
(Expr
));
3920 Ofs
:= Expr_Value
(Right_Opnd
(Expr
));
3922 -- Case of expression is entity - known constant
3924 elsif Nkind
(Expr
) = N_Op_Subtract
3925 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
3926 and then Is_Entity_Name
(Left_Opnd
(Expr
))
3928 Ent
:= Entity
(Left_Opnd
(Expr
));
3929 Ofs
:= UI_Negate
(Expr_Value
(Right_Opnd
(Expr
)));
3931 -- Any other expression is not of the right form
3940 -- Come here with expression of appropriate form, check if
3941 -- entity is an appropriate one for our purposes.
3943 if (Ekind
(Ent
) = E_Variable
3945 Ekind
(Ent
) = E_Constant
3947 Ekind
(Ent
) = E_Loop_Parameter
3949 Ekind
(Ent
) = E_In_Parameter
)
3950 and then not Is_Library_Level_Entity
(Ent
)
3958 -- See if there is matching check already
3960 for J
in reverse 1 .. Num_Saved_Checks
loop
3962 SC
: Saved_Check
renames Saved_Checks
(J
);
3965 if SC
.Killed
= False
3966 and then SC
.Entity
= Ent
3967 and then SC
.Offset
= Ofs
3968 and then SC
.Check_Type
= Check_Type
3969 and then Within_Range_Of
(Target_Type
, SC
.Target_Type
)
3977 -- If we fall through entry was not found
3983 ---------------------------------
3984 -- Generate_Discriminant_Check --
3985 ---------------------------------
3987 -- Note: the code for this procedure is derived from the
3988 -- emit_discriminant_check routine a-trans.c v1.659.
3990 procedure Generate_Discriminant_Check
(N
: Node_Id
) is
3991 Loc
: constant Source_Ptr
:= Sloc
(N
);
3992 Pref
: constant Node_Id
:= Prefix
(N
);
3993 Sel
: constant Node_Id
:= Selector_Name
(N
);
3995 Orig_Comp
: constant Entity_Id
:=
3996 Original_Record_Component
(Entity
(Sel
));
3997 -- The original component to be checked
3999 Discr_Fct
: constant Entity_Id
:=
4000 Discriminant_Checking_Func
(Orig_Comp
);
4001 -- The discriminant checking function
4004 -- One discriminant to be checked in the type
4006 Real_Discr
: Entity_Id
;
4007 -- Actual discriminant in the call
4009 Pref_Type
: Entity_Id
;
4010 -- Type of relevant prefix (ignoring private/access stuff)
4013 -- List of arguments for function call
4016 -- Keep track of the formal corresponding to the actual we build
4017 -- for each discriminant, in order to be able to perform the
4018 -- necessary type conversions.
4021 -- Selected component reference for checking function argument
4024 Pref_Type
:= Etype
(Pref
);
4026 -- Force evaluation of the prefix, so that it does not get evaluated
4027 -- twice (once for the check, once for the actual reference). Such a
4028 -- double evaluation is always a potential source of inefficiency,
4029 -- and is functionally incorrect in the volatile case, or when the
4030 -- prefix may have side-effects. An entity or a component of an
4031 -- entity requires no evaluation.
4033 if Is_Entity_Name
(Pref
) then
4034 if Treat_As_Volatile
(Entity
(Pref
)) then
4035 Force_Evaluation
(Pref
, Name_Req
=> True);
4038 elsif Treat_As_Volatile
(Etype
(Pref
)) then
4039 Force_Evaluation
(Pref
, Name_Req
=> True);
4041 elsif Nkind
(Pref
) = N_Selected_Component
4042 and then Is_Entity_Name
(Prefix
(Pref
))
4047 Force_Evaluation
(Pref
, Name_Req
=> True);
4050 -- For a tagged type, use the scope of the original component to
4051 -- obtain the type, because ???
4053 if Is_Tagged_Type
(Scope
(Orig_Comp
)) then
4054 Pref_Type
:= Scope
(Orig_Comp
);
4056 -- For an untagged derived type, use the discriminants of the
4057 -- parent which have been renamed in the derivation, possibly
4058 -- by a one-to-many discriminant constraint.
4059 -- For non-tagged type, initially get the Etype of the prefix
4062 if Is_Derived_Type
(Pref_Type
)
4063 and then Number_Discriminants
(Pref_Type
) /=
4064 Number_Discriminants
(Etype
(Base_Type
(Pref_Type
)))
4066 Pref_Type
:= Etype
(Base_Type
(Pref_Type
));
4070 -- We definitely should have a checking function, This routine should
4071 -- not be called if no discriminant checking function is present.
4073 pragma Assert
(Present
(Discr_Fct
));
4075 -- Create the list of the actual parameters for the call. This list
4076 -- is the list of the discriminant fields of the record expression to
4077 -- be discriminant checked.
4080 Formal
:= First_Formal
(Discr_Fct
);
4081 Discr
:= First_Discriminant
(Pref_Type
);
4082 while Present
(Discr
) loop
4084 -- If we have a corresponding discriminant field, and a parent
4085 -- subtype is present, then we want to use the corresponding
4086 -- discriminant since this is the one with the useful value.
4088 if Present
(Corresponding_Discriminant
(Discr
))
4089 and then Ekind
(Pref_Type
) = E_Record_Type
4090 and then Present
(Parent_Subtype
(Pref_Type
))
4092 Real_Discr
:= Corresponding_Discriminant
(Discr
);
4094 Real_Discr
:= Discr
;
4097 -- Construct the reference to the discriminant
4100 Make_Selected_Component
(Loc
,
4102 Unchecked_Convert_To
(Pref_Type
,
4103 Duplicate_Subexpr
(Pref
)),
4104 Selector_Name
=> New_Occurrence_Of
(Real_Discr
, Loc
));
4106 -- Manually analyze and resolve this selected component. We really
4107 -- want it just as it appears above, and do not want the expander
4108 -- playing discriminal games etc with this reference. Then we
4109 -- append the argument to the list we are gathering.
4111 Set_Etype
(Scomp
, Etype
(Real_Discr
));
4112 Set_Analyzed
(Scomp
, True);
4113 Append_To
(Args
, Convert_To
(Etype
(Formal
), Scomp
));
4115 Next_Formal_With_Extras
(Formal
);
4116 Next_Discriminant
(Discr
);
4119 -- Now build and insert the call
4122 Make_Raise_Constraint_Error
(Loc
,
4124 Make_Function_Call
(Loc
,
4125 Name
=> New_Occurrence_Of
(Discr_Fct
, Loc
),
4126 Parameter_Associations
=> Args
),
4127 Reason
=> CE_Discriminant_Check_Failed
));
4128 end Generate_Discriminant_Check
;
4130 ---------------------------
4131 -- Generate_Index_Checks --
4132 ---------------------------
4134 procedure Generate_Index_Checks
(N
: Node_Id
) is
4135 Loc
: constant Source_Ptr
:= Sloc
(N
);
4136 A
: constant Node_Id
:= Prefix
(N
);
4142 Sub
:= First
(Expressions
(N
));
4144 while Present
(Sub
) loop
4145 if Do_Range_Check
(Sub
) then
4146 Set_Do_Range_Check
(Sub
, False);
4148 -- Force evaluation except for the case of a simple name of
4149 -- a non-volatile entity.
4151 if not Is_Entity_Name
(Sub
)
4152 or else Treat_As_Volatile
(Entity
(Sub
))
4154 Force_Evaluation
(Sub
);
4157 -- Generate a raise of constraint error with the appropriate
4158 -- reason and a condition of the form:
4160 -- Base_Type(Sub) not in array'range (subscript)
4162 -- Note that the reason we generate the conversion to the
4163 -- base type here is that we definitely want the range check
4164 -- to take place, even if it looks like the subtype is OK.
4165 -- Optimization considerations that allow us to omit the
4166 -- check have already been taken into account in the setting
4167 -- of the Do_Range_Check flag earlier on.
4172 Num
:= New_List
(Make_Integer_Literal
(Loc
, Ind
));
4176 Make_Raise_Constraint_Error
(Loc
,
4180 Convert_To
(Base_Type
(Etype
(Sub
)),
4181 Duplicate_Subexpr_Move_Checks
(Sub
)),
4183 Make_Attribute_Reference
(Loc
,
4184 Prefix
=> Duplicate_Subexpr_Move_Checks
(A
),
4185 Attribute_Name
=> Name_Range
,
4186 Expressions
=> Num
)),
4187 Reason
=> CE_Index_Check_Failed
));
4193 end Generate_Index_Checks
;
4195 --------------------------
4196 -- Generate_Range_Check --
4197 --------------------------
4199 procedure Generate_Range_Check
4201 Target_Type
: Entity_Id
;
4202 Reason
: RT_Exception_Code
)
4204 Loc
: constant Source_Ptr
:= Sloc
(N
);
4205 Source_Type
: constant Entity_Id
:= Etype
(N
);
4206 Source_Base_Type
: constant Entity_Id
:= Base_Type
(Source_Type
);
4207 Target_Base_Type
: constant Entity_Id
:= Base_Type
(Target_Type
);
4210 -- First special case, if the source type is already within the
4211 -- range of the target type, then no check is needed (probably we
4212 -- should have stopped Do_Range_Check from being set in the first
4213 -- place, but better late than later in preventing junk code!
4215 -- We do NOT apply this if the source node is a literal, since in
4216 -- this case the literal has already been labeled as having the
4217 -- subtype of the target.
4219 if In_Subrange_Of
(Source_Type
, Target_Type
)
4221 (Nkind
(N
) = N_Integer_Literal
4223 Nkind
(N
) = N_Real_Literal
4225 Nkind
(N
) = N_Character_Literal
4228 and then Ekind
(Entity
(N
)) = E_Enumeration_Literal
))
4233 -- We need a check, so force evaluation of the node, so that it does
4234 -- not get evaluated twice (once for the check, once for the actual
4235 -- reference). Such a double evaluation is always a potential source
4236 -- of inefficiency, and is functionally incorrect in the volatile case.
4238 if not Is_Entity_Name
(N
)
4239 or else Treat_As_Volatile
(Entity
(N
))
4241 Force_Evaluation
(N
);
4244 -- The easiest case is when Source_Base_Type and Target_Base_Type
4245 -- are the same since in this case we can simply do a direct
4246 -- check of the value of N against the bounds of Target_Type.
4248 -- [constraint_error when N not in Target_Type]
4250 -- Note: this is by far the most common case, for example all cases of
4251 -- checks on the RHS of assignments are in this category, but not all
4252 -- cases are like this. Notably conversions can involve two types.
4254 if Source_Base_Type
= Target_Base_Type
then
4256 Make_Raise_Constraint_Error
(Loc
,
4259 Left_Opnd
=> Duplicate_Subexpr
(N
),
4260 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
4263 -- Next test for the case where the target type is within the bounds
4264 -- of the base type of the source type, since in this case we can
4265 -- simply convert these bounds to the base type of T to do the test.
4267 -- [constraint_error when N not in
4268 -- Source_Base_Type (Target_Type'First)
4270 -- Source_Base_Type(Target_Type'Last))]
4272 -- The conversions will always work and need no check
4274 elsif In_Subrange_Of
(Target_Type
, Source_Base_Type
) then
4276 Make_Raise_Constraint_Error
(Loc
,
4279 Left_Opnd
=> Duplicate_Subexpr
(N
),
4284 Convert_To
(Source_Base_Type
,
4285 Make_Attribute_Reference
(Loc
,
4287 New_Occurrence_Of
(Target_Type
, Loc
),
4288 Attribute_Name
=> Name_First
)),
4291 Convert_To
(Source_Base_Type
,
4292 Make_Attribute_Reference
(Loc
,
4294 New_Occurrence_Of
(Target_Type
, Loc
),
4295 Attribute_Name
=> Name_Last
)))),
4298 -- Note that at this stage we now that the Target_Base_Type is
4299 -- not in the range of the Source_Base_Type (since even the
4300 -- Target_Type itself is not in this range). It could still be
4301 -- the case that the Source_Type is in range of the target base
4302 -- type, since we have not checked that case.
4304 -- If that is the case, we can freely convert the source to the
4305 -- target, and then test the target result against the bounds.
4307 elsif In_Subrange_Of
(Source_Type
, Target_Base_Type
) then
4309 -- We make a temporary to hold the value of the converted
4310 -- value (converted to the base type), and then we will
4311 -- do the test against this temporary.
4313 -- Tnn : constant Target_Base_Type := Target_Base_Type (N);
4314 -- [constraint_error when Tnn not in Target_Type]
4316 -- Then the conversion itself is replaced by an occurrence of Tnn
4319 Tnn
: constant Entity_Id
:=
4320 Make_Defining_Identifier
(Loc
,
4321 Chars
=> New_Internal_Name
('T'));
4324 Insert_Actions
(N
, New_List
(
4325 Make_Object_Declaration
(Loc
,
4326 Defining_Identifier
=> Tnn
,
4327 Object_Definition
=>
4328 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4329 Constant_Present
=> True,
4331 Make_Type_Conversion
(Loc
,
4332 Subtype_Mark
=> New_Occurrence_Of
(Target_Base_Type
, Loc
),
4333 Expression
=> Duplicate_Subexpr
(N
))),
4335 Make_Raise_Constraint_Error
(Loc
,
4338 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
4339 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
4341 Reason
=> Reason
)));
4343 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
4346 -- At this stage, we know that we have two scalar types, which are
4347 -- directly convertible, and where neither scalar type has a base
4348 -- range that is in the range of the other scalar type.
4350 -- The only way this can happen is with a signed and unsigned type.
4351 -- So test for these two cases:
4354 -- Case of the source is unsigned and the target is signed
4356 if Is_Unsigned_Type
(Source_Base_Type
)
4357 and then not Is_Unsigned_Type
(Target_Base_Type
)
4359 -- If the source is unsigned and the target is signed, then we
4360 -- know that the source is not shorter than the target (otherwise
4361 -- the source base type would be in the target base type range).
4363 -- In other words, the unsigned type is either the same size
4364 -- as the target, or it is larger. It cannot be smaller.
4367 (Esize
(Source_Base_Type
) >= Esize
(Target_Base_Type
));
4369 -- We only need to check the low bound if the low bound of the
4370 -- target type is non-negative. If the low bound of the target
4371 -- type is negative, then we know that we will fit fine.
4373 -- If the high bound of the target type is negative, then we
4374 -- know we have a constraint error, since we can't possibly
4375 -- have a negative source.
4377 -- With these two checks out of the way, we can do the check
4378 -- using the source type safely
4380 -- This is definitely the most annoying case!
4382 -- [constraint_error
4383 -- when (Target_Type'First >= 0
4385 -- N < Source_Base_Type (Target_Type'First))
4386 -- or else Target_Type'Last < 0
4387 -- or else N > Source_Base_Type (Target_Type'Last)];
4389 -- We turn off all checks since we know that the conversions
4390 -- will work fine, given the guards for negative values.
4393 Make_Raise_Constraint_Error
(Loc
,
4399 Left_Opnd
=> Make_Op_Ge
(Loc
,
4401 Make_Attribute_Reference
(Loc
,
4403 New_Occurrence_Of
(Target_Type
, Loc
),
4404 Attribute_Name
=> Name_First
),
4405 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
4409 Left_Opnd
=> Duplicate_Subexpr
(N
),
4411 Convert_To
(Source_Base_Type
,
4412 Make_Attribute_Reference
(Loc
,
4414 New_Occurrence_Of
(Target_Type
, Loc
),
4415 Attribute_Name
=> Name_First
)))),
4420 Make_Attribute_Reference
(Loc
,
4421 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
4422 Attribute_Name
=> Name_Last
),
4423 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
))),
4427 Left_Opnd
=> Duplicate_Subexpr
(N
),
4429 Convert_To
(Source_Base_Type
,
4430 Make_Attribute_Reference
(Loc
,
4431 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
4432 Attribute_Name
=> Name_Last
)))),
4435 Suppress
=> All_Checks
);
4437 -- Only remaining possibility is that the source is signed and
4438 -- the target is unsigned
4441 pragma Assert
(not Is_Unsigned_Type
(Source_Base_Type
)
4442 and then Is_Unsigned_Type
(Target_Base_Type
));
4444 -- If the source is signed and the target is unsigned, then
4445 -- we know that the target is not shorter than the source
4446 -- (otherwise the target base type would be in the source
4447 -- base type range).
4449 -- In other words, the unsigned type is either the same size
4450 -- as the target, or it is larger. It cannot be smaller.
4452 -- Clearly we have an error if the source value is negative
4453 -- since no unsigned type can have negative values. If the
4454 -- source type is non-negative, then the check can be done
4455 -- using the target type.
4457 -- Tnn : constant Target_Base_Type (N) := Target_Type;
4459 -- [constraint_error
4460 -- when N < 0 or else Tnn not in Target_Type];
4462 -- We turn off all checks for the conversion of N to the
4463 -- target base type, since we generate the explicit check
4464 -- to ensure that the value is non-negative
4467 Tnn
: constant Entity_Id
:=
4468 Make_Defining_Identifier
(Loc
,
4469 Chars
=> New_Internal_Name
('T'));
4472 Insert_Actions
(N
, New_List
(
4473 Make_Object_Declaration
(Loc
,
4474 Defining_Identifier
=> Tnn
,
4475 Object_Definition
=>
4476 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4477 Constant_Present
=> True,
4479 Make_Type_Conversion
(Loc
,
4481 New_Occurrence_Of
(Target_Base_Type
, Loc
),
4482 Expression
=> Duplicate_Subexpr
(N
))),
4484 Make_Raise_Constraint_Error
(Loc
,
4489 Left_Opnd
=> Duplicate_Subexpr
(N
),
4490 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
4494 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
4496 New_Occurrence_Of
(Target_Type
, Loc
))),
4499 Suppress
=> All_Checks
);
4501 -- Set the Etype explicitly, because Insert_Actions may
4502 -- have placed the declaration in the freeze list for an
4503 -- enclosing construct, and thus it is not analyzed yet.
4505 Set_Etype
(Tnn
, Target_Base_Type
);
4506 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
4510 end Generate_Range_Check
;
4512 ---------------------
4513 -- Get_Discriminal --
4514 ---------------------
4516 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
is
4517 Loc
: constant Source_Ptr
:= Sloc
(E
);
4522 -- The entity E is the type of a private component of the protected
4523 -- type, or the type of a renaming of that component within a protected
4524 -- operation of that type.
4528 if Ekind
(Sc
) /= E_Protected_Type
then
4531 if Ekind
(Sc
) /= E_Protected_Type
then
4536 D
:= First_Discriminant
(Sc
);
4539 and then Chars
(D
) /= Chars
(Bound
)
4541 Next_Discriminant
(D
);
4544 return New_Occurrence_Of
(Discriminal
(D
), Loc
);
4545 end Get_Discriminal
;
4551 function Guard_Access
4554 Ck_Node
: Node_Id
) return Node_Id
4557 if Nkind
(Cond
) = N_Or_Else
then
4558 Set_Paren_Count
(Cond
, 1);
4561 if Nkind
(Ck_Node
) = N_Allocator
then
4568 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
4569 Right_Opnd
=> Make_Null
(Loc
)),
4570 Right_Opnd
=> Cond
);
4574 -----------------------------
4575 -- Index_Checks_Suppressed --
4576 -----------------------------
4578 function Index_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4580 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4581 return Is_Check_Suppressed
(E
, Index_Check
);
4583 return Scope_Suppress
(Index_Check
);
4585 end Index_Checks_Suppressed
;
4591 procedure Initialize
is
4593 for J
in Determine_Range_Cache_N
'Range loop
4594 Determine_Range_Cache_N
(J
) := Empty
;
4598 -------------------------
4599 -- Insert_Range_Checks --
4600 -------------------------
4602 procedure Insert_Range_Checks
4603 (Checks
: Check_Result
;
4605 Suppress_Typ
: Entity_Id
;
4606 Static_Sloc
: Source_Ptr
:= No_Location
;
4607 Flag_Node
: Node_Id
:= Empty
;
4608 Do_Before
: Boolean := False)
4610 Internal_Flag_Node
: Node_Id
:= Flag_Node
;
4611 Internal_Static_Sloc
: Source_Ptr
:= Static_Sloc
;
4613 Check_Node
: Node_Id
;
4614 Checks_On
: constant Boolean :=
4615 (not Index_Checks_Suppressed
(Suppress_Typ
))
4617 (not Range_Checks_Suppressed
(Suppress_Typ
));
4620 -- For now we just return if Checks_On is false, however this should
4621 -- be enhanced to check for an always True value in the condition
4622 -- and to generate a compilation warning???
4624 if not Expander_Active
or else not Checks_On
then
4628 if Static_Sloc
= No_Location
then
4629 Internal_Static_Sloc
:= Sloc
(Node
);
4632 if No
(Flag_Node
) then
4633 Internal_Flag_Node
:= Node
;
4636 for J
in 1 .. 2 loop
4637 exit when No
(Checks
(J
));
4639 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
4640 and then Present
(Condition
(Checks
(J
)))
4642 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
4643 Check_Node
:= Checks
(J
);
4644 Mark_Rewrite_Insertion
(Check_Node
);
4647 Insert_Before_And_Analyze
(Node
, Check_Node
);
4649 Insert_After_And_Analyze
(Node
, Check_Node
);
4652 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
4657 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
4658 Reason
=> CE_Range_Check_Failed
);
4659 Mark_Rewrite_Insertion
(Check_Node
);
4662 Insert_Before_And_Analyze
(Node
, Check_Node
);
4664 Insert_After_And_Analyze
(Node
, Check_Node
);
4668 end Insert_Range_Checks
;
4670 ------------------------
4671 -- Insert_Valid_Check --
4672 ------------------------
4674 procedure Insert_Valid_Check
(Expr
: Node_Id
) is
4675 Loc
: constant Source_Ptr
:= Sloc
(Expr
);
4679 -- Do not insert if checks off, or if not checking validity
4681 if Range_Checks_Suppressed
(Etype
(Expr
))
4682 or else (not Validity_Checks_On
)
4687 -- If we have a checked conversion, then validity check applies to
4688 -- the expression inside the conversion, not the result, since if
4689 -- the expression inside is valid, then so is the conversion result.
4692 while Nkind
(Exp
) = N_Type_Conversion
loop
4693 Exp
:= Expression
(Exp
);
4696 -- Insert the validity check. Note that we do this with validity
4697 -- checks turned off, to avoid recursion, we do not want validity
4698 -- checks on the validity checking code itself!
4700 Validity_Checks_On
:= False;
4703 Make_Raise_Constraint_Error
(Loc
,
4707 Make_Attribute_Reference
(Loc
,
4709 Duplicate_Subexpr_No_Checks
(Exp
, Name_Req
=> True),
4710 Attribute_Name
=> Name_Valid
)),
4711 Reason
=> CE_Invalid_Data
),
4712 Suppress
=> All_Checks
);
4714 -- If the expression is a a reference to an element of a bit-packed
4715 -- array, it is rewritten as a renaming declaration. If the expression
4716 -- is an actual in a call, it has not been expanded, waiting for the
4717 -- proper point at which to do it. The same happens with renamings, so
4718 -- that we have to force the expansion now. This non-local complication
4719 -- is due to code in exp_ch2,adb, exp_ch4.adb and exp_ch6.adb.
4721 if Is_Entity_Name
(Exp
)
4722 and then Nkind
(Parent
(Entity
(Exp
))) = N_Object_Renaming_Declaration
4725 Old_Exp
: constant Node_Id
:= Name
(Parent
(Entity
(Exp
)));
4727 if Nkind
(Old_Exp
) = N_Indexed_Component
4728 and then Is_Bit_Packed_Array
(Etype
(Prefix
(Old_Exp
)))
4730 Expand_Packed_Element_Reference
(Old_Exp
);
4735 Validity_Checks_On
:= True;
4736 end Insert_Valid_Check
;
4738 ----------------------------------
4739 -- Install_Null_Excluding_Check --
4740 ----------------------------------
4742 procedure Install_Null_Excluding_Check
(N
: Node_Id
) is
4743 Loc
: constant Source_Ptr
:= Sloc
(N
);
4744 Etyp
: constant Entity_Id
:= Etype
(N
);
4747 pragma Assert
(Is_Access_Type
(Etyp
));
4749 -- Don't need access check if:
4750 -- 1) we are analyzing a generic
4751 -- 2) it is known to be non-null
4752 -- 3) the check was suppressed on the type
4753 -- 4) This is an attribute reference that returns an access type.
4756 or else Access_Checks_Suppressed
(Etyp
)
4759 elsif Nkind
(N
) = N_Attribute_Reference
4761 (Attribute_Name
(N
) = Name_Access
4763 Attribute_Name
(N
) = Name_Unchecked_Access
4765 Attribute_Name
(N
) = Name_Unrestricted_Access
)
4768 -- Otherwise install access check
4772 Make_Raise_Constraint_Error
(Loc
,
4775 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(N
),
4776 Right_Opnd
=> Make_Null
(Loc
)),
4777 Reason
=> CE_Access_Check_Failed
));
4779 end Install_Null_Excluding_Check
;
4781 --------------------------
4782 -- Install_Static_Check --
4783 --------------------------
4785 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
) is
4786 Stat
: constant Boolean := Is_Static_Expression
(R_Cno
);
4787 Typ
: constant Entity_Id
:= Etype
(R_Cno
);
4791 Make_Raise_Constraint_Error
(Loc
,
4792 Reason
=> CE_Range_Check_Failed
));
4793 Set_Analyzed
(R_Cno
);
4794 Set_Etype
(R_Cno
, Typ
);
4795 Set_Raises_Constraint_Error
(R_Cno
);
4796 Set_Is_Static_Expression
(R_Cno
, Stat
);
4797 end Install_Static_Check
;
4799 ---------------------
4800 -- Kill_All_Checks --
4801 ---------------------
4803 procedure Kill_All_Checks
is
4805 if Debug_Flag_CC
then
4806 w
("Kill_All_Checks");
4809 -- We reset the number of saved checks to zero, and also modify
4810 -- all stack entries for statement ranges to indicate that the
4811 -- number of checks at each level is now zero.
4813 Num_Saved_Checks
:= 0;
4815 for J
in 1 .. Saved_Checks_TOS
loop
4816 Saved_Checks_Stack
(J
) := 0;
4818 end Kill_All_Checks
;
4824 procedure Kill_Checks
(V
: Entity_Id
) is
4826 if Debug_Flag_CC
then
4827 w
("Kill_Checks for entity", Int
(V
));
4830 for J
in 1 .. Num_Saved_Checks
loop
4831 if Saved_Checks
(J
).Entity
= V
then
4832 if Debug_Flag_CC
then
4833 w
(" Checks killed for saved check ", J
);
4836 Saved_Checks
(J
).Killed
:= True;
4841 ------------------------------
4842 -- Length_Checks_Suppressed --
4843 ------------------------------
4845 function Length_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4847 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4848 return Is_Check_Suppressed
(E
, Length_Check
);
4850 return Scope_Suppress
(Length_Check
);
4852 end Length_Checks_Suppressed
;
4854 --------------------------------
4855 -- Overflow_Checks_Suppressed --
4856 --------------------------------
4858 function Overflow_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4860 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
4861 return Is_Check_Suppressed
(E
, Overflow_Check
);
4863 return Scope_Suppress
(Overflow_Check
);
4865 end Overflow_Checks_Suppressed
;
4871 function Range_Check
4873 Target_Typ
: Entity_Id
;
4874 Source_Typ
: Entity_Id
:= Empty
;
4875 Warn_Node
: Node_Id
:= Empty
) return Check_Result
4878 return Selected_Range_Checks
4879 (Ck_Node
, Target_Typ
, Source_Typ
, Warn_Node
);
4882 -----------------------------
4883 -- Range_Checks_Suppressed --
4884 -----------------------------
4886 function Range_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
4890 -- Note: for now we always suppress range checks on Vax float types,
4891 -- since Gigi does not know how to generate these checks.
4893 if Vax_Float
(E
) then
4895 elsif Kill_Range_Checks
(E
) then
4897 elsif Checks_May_Be_Suppressed
(E
) then
4898 return Is_Check_Suppressed
(E
, Range_Check
);
4902 return Scope_Suppress
(Range_Check
);
4903 end Range_Checks_Suppressed
;
4909 procedure Remove_Checks
(Expr
: Node_Id
) is
4910 Discard
: Traverse_Result
;
4911 pragma Warnings
(Off
, Discard
);
4913 function Process
(N
: Node_Id
) return Traverse_Result
;
4914 -- Process a single node during the traversal
4916 function Traverse
is new Traverse_Func
(Process
);
4917 -- The traversal function itself
4923 function Process
(N
: Node_Id
) return Traverse_Result
is
4925 if Nkind
(N
) not in N_Subexpr
then
4929 Set_Do_Range_Check
(N
, False);
4933 Discard
:= Traverse
(Left_Opnd
(N
));
4936 when N_Attribute_Reference
=>
4937 Set_Do_Overflow_Check
(N
, False);
4939 when N_Function_Call
=>
4940 Set_Do_Tag_Check
(N
, False);
4943 Set_Do_Overflow_Check
(N
, False);
4947 Set_Do_Division_Check
(N
, False);
4950 Set_Do_Length_Check
(N
, False);
4953 Set_Do_Division_Check
(N
, False);
4956 Set_Do_Length_Check
(N
, False);
4959 Set_Do_Division_Check
(N
, False);
4962 Set_Do_Length_Check
(N
, False);
4969 Discard
:= Traverse
(Left_Opnd
(N
));
4972 when N_Selected_Component
=>
4973 Set_Do_Discriminant_Check
(N
, False);
4975 when N_Type_Conversion
=>
4976 Set_Do_Length_Check
(N
, False);
4977 Set_Do_Tag_Check
(N
, False);
4978 Set_Do_Overflow_Check
(N
, False);
4987 -- Start of processing for Remove_Checks
4990 Discard
:= Traverse
(Expr
);
4993 ----------------------------
4994 -- Selected_Length_Checks --
4995 ----------------------------
4997 function Selected_Length_Checks
4999 Target_Typ
: Entity_Id
;
5000 Source_Typ
: Entity_Id
;
5001 Warn_Node
: Node_Id
) return Check_Result
5003 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
5006 Expr_Actual
: Node_Id
;
5008 Cond
: Node_Id
:= Empty
;
5009 Do_Access
: Boolean := False;
5010 Wnode
: Node_Id
:= Warn_Node
;
5011 Ret_Result
: Check_Result
:= (Empty
, Empty
);
5012 Num_Checks
: Natural := 0;
5014 procedure Add_Check
(N
: Node_Id
);
5015 -- Adds the action given to Ret_Result if N is non-Empty
5017 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
;
5018 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5019 -- Comments required ???
5021 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean;
5022 -- True for equal literals and for nodes that denote the same constant
5023 -- entity, even if its value is not a static constant. This includes the
5024 -- case of a discriminal reference within an init proc. Removes some
5025 -- obviously superfluous checks.
5027 function Length_E_Cond
5028 (Exptyp
: Entity_Id
;
5030 Indx
: Nat
) return Node_Id
;
5031 -- Returns expression to compute:
5032 -- Typ'Length /= Exptyp'Length
5034 function Length_N_Cond
5037 Indx
: Nat
) return Node_Id
;
5038 -- Returns expression to compute:
5039 -- Typ'Length /= Expr'Length
5045 procedure Add_Check
(N
: Node_Id
) is
5049 -- For now, ignore attempt to place more than 2 checks ???
5051 if Num_Checks
= 2 then
5055 pragma Assert
(Num_Checks
<= 1);
5056 Num_Checks
:= Num_Checks
+ 1;
5057 Ret_Result
(Num_Checks
) := N
;
5065 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
is
5066 Pt
: constant Entity_Id
:= Scope
(Scope
(E
));
5068 E1
: Entity_Id
:= E
;
5071 if Ekind
(Scope
(E
)) = E_Record_Type
5072 and then Has_Discriminants
(Scope
(E
))
5074 N
:= Build_Discriminal_Subtype_Of_Component
(E
);
5077 Insert_Action
(Ck_Node
, N
);
5078 E1
:= Defining_Identifier
(N
);
5082 if Ekind
(E1
) = E_String_Literal_Subtype
then
5084 Make_Integer_Literal
(Loc
,
5085 Intval
=> String_Literal_Length
(E1
));
5087 elsif Ekind
(Pt
) = E_Protected_Type
5088 and then Has_Discriminants
(Pt
)
5089 and then Has_Completion
(Pt
)
5090 and then not Inside_Init_Proc
5093 -- If the type whose length is needed is a private component
5094 -- constrained by a discriminant, we must expand the 'Length
5095 -- attribute into an explicit computation, using the discriminal
5096 -- of the current protected operation. This is because the actual
5097 -- type of the prival is constructed after the protected opera-
5098 -- tion has been fully expanded.
5101 Indx_Type
: Node_Id
;
5104 Do_Expand
: Boolean := False;
5107 Indx_Type
:= First_Index
(E
);
5109 for J
in 1 .. Indx
- 1 loop
5110 Next_Index
(Indx_Type
);
5113 Get_Index_Bounds
(Indx_Type
, Lo
, Hi
);
5115 if Nkind
(Lo
) = N_Identifier
5116 and then Ekind
(Entity
(Lo
)) = E_In_Parameter
5118 Lo
:= Get_Discriminal
(E
, Lo
);
5122 if Nkind
(Hi
) = N_Identifier
5123 and then Ekind
(Entity
(Hi
)) = E_In_Parameter
5125 Hi
:= Get_Discriminal
(E
, Hi
);
5130 if not Is_Entity_Name
(Lo
) then
5131 Lo
:= Duplicate_Subexpr_No_Checks
(Lo
);
5134 if not Is_Entity_Name
(Hi
) then
5135 Lo
:= Duplicate_Subexpr_No_Checks
(Hi
);
5141 Make_Op_Subtract
(Loc
,
5145 Right_Opnd
=> Make_Integer_Literal
(Loc
, 1));
5150 Make_Attribute_Reference
(Loc
,
5151 Attribute_Name
=> Name_Length
,
5153 New_Occurrence_Of
(E1
, Loc
));
5156 Set_Expressions
(N
, New_List
(
5157 Make_Integer_Literal
(Loc
, Indx
)));
5166 Make_Attribute_Reference
(Loc
,
5167 Attribute_Name
=> Name_Length
,
5169 New_Occurrence_Of
(E1
, Loc
));
5172 Set_Expressions
(N
, New_List
(
5173 Make_Integer_Literal
(Loc
, Indx
)));
5185 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5188 Make_Attribute_Reference
(Loc
,
5189 Attribute_Name
=> Name_Length
,
5191 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5192 Expressions
=> New_List
(
5193 Make_Integer_Literal
(Loc
, Indx
)));
5201 function Length_E_Cond
5202 (Exptyp
: Entity_Id
;
5204 Indx
: Nat
) return Node_Id
5209 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
5210 Right_Opnd
=> Get_E_Length
(Exptyp
, Indx
));
5218 function Length_N_Cond
5221 Indx
: Nat
) return Node_Id
5226 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
5227 Right_Opnd
=> Get_N_Length
(Expr
, Indx
));
5231 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean is
5234 (Nkind
(L
) = N_Integer_Literal
5235 and then Nkind
(R
) = N_Integer_Literal
5236 and then Intval
(L
) = Intval
(R
))
5240 and then Ekind
(Entity
(L
)) = E_Constant
5241 and then ((Is_Entity_Name
(R
)
5242 and then Entity
(L
) = Entity
(R
))
5244 (Nkind
(R
) = N_Type_Conversion
5245 and then Is_Entity_Name
(Expression
(R
))
5246 and then Entity
(L
) = Entity
(Expression
(R
)))))
5250 and then Ekind
(Entity
(R
)) = E_Constant
5251 and then Nkind
(L
) = N_Type_Conversion
5252 and then Is_Entity_Name
(Expression
(L
))
5253 and then Entity
(R
) = Entity
(Expression
(L
)))
5257 and then Is_Entity_Name
(R
)
5258 and then Entity
(L
) = Entity
(R
)
5259 and then Ekind
(Entity
(L
)) = E_In_Parameter
5260 and then Inside_Init_Proc
);
5263 -- Start of processing for Selected_Length_Checks
5266 if not Expander_Active
then
5270 if Target_Typ
= Any_Type
5271 or else Target_Typ
= Any_Composite
5272 or else Raises_Constraint_Error
(Ck_Node
)
5281 T_Typ
:= Target_Typ
;
5283 if No
(Source_Typ
) then
5284 S_Typ
:= Etype
(Ck_Node
);
5286 S_Typ
:= Source_Typ
;
5289 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
5293 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
5294 S_Typ
:= Designated_Type
(S_Typ
);
5295 T_Typ
:= Designated_Type
(T_Typ
);
5298 -- A simple optimization
5300 if Nkind
(Ck_Node
) = N_Null
then
5305 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
5306 if Is_Constrained
(T_Typ
) then
5308 -- The checking code to be generated will freeze the
5309 -- corresponding array type. However, we must freeze the
5310 -- type now, so that the freeze node does not appear within
5311 -- the generated condional expression, but ahead of it.
5313 Freeze_Before
(Ck_Node
, T_Typ
);
5315 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
5316 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
5318 if Is_Access_Type
(Exptyp
) then
5319 Exptyp
:= Designated_Type
(Exptyp
);
5322 -- String_Literal case. This needs to be handled specially be-
5323 -- cause no index types are available for string literals. The
5324 -- condition is simply:
5326 -- T_Typ'Length = string-literal-length
5328 if Nkind
(Expr_Actual
) = N_String_Literal
5329 and then Ekind
(Etype
(Expr_Actual
)) = E_String_Literal_Subtype
5333 Left_Opnd
=> Get_E_Length
(T_Typ
, 1),
5335 Make_Integer_Literal
(Loc
,
5337 String_Literal_Length
(Etype
(Expr_Actual
))));
5339 -- General array case. Here we have a usable actual subtype for
5340 -- the expression, and the condition is built from the two types
5343 -- T_Typ'Length /= Exptyp'Length or else
5344 -- T_Typ'Length (2) /= Exptyp'Length (2) or else
5345 -- T_Typ'Length (3) /= Exptyp'Length (3) or else
5348 elsif Is_Constrained
(Exptyp
) then
5350 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
5364 -- At the library level, we need to ensure that the
5365 -- type of the object is elaborated before the check
5366 -- itself is emitted. This is only done if the object
5367 -- is in the current compilation unit, otherwise the
5368 -- type is frozen and elaborated in its unit.
5370 if Is_Itype
(Exptyp
)
5372 Ekind
(Cunit_Entity
(Current_Sem_Unit
)) = E_Package
5374 not In_Package_Body
(Cunit_Entity
(Current_Sem_Unit
))
5375 and then In_Open_Scopes
(Scope
(Exptyp
))
5377 Ref_Node
:= Make_Itype_Reference
(Sloc
(Ck_Node
));
5378 Set_Itype
(Ref_Node
, Exptyp
);
5379 Insert_Action
(Ck_Node
, Ref_Node
);
5382 L_Index
:= First_Index
(T_Typ
);
5383 R_Index
:= First_Index
(Exptyp
);
5385 for Indx
in 1 .. Ndims
loop
5386 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
5388 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
5390 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
5391 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
5393 -- Deal with compile time length check. Note that we
5394 -- skip this in the access case, because the access
5395 -- value may be null, so we cannot know statically.
5398 and then Compile_Time_Known_Value
(L_Low
)
5399 and then Compile_Time_Known_Value
(L_High
)
5400 and then Compile_Time_Known_Value
(R_Low
)
5401 and then Compile_Time_Known_Value
(R_High
)
5403 if Expr_Value
(L_High
) >= Expr_Value
(L_Low
) then
5404 L_Length
:= Expr_Value
(L_High
) -
5405 Expr_Value
(L_Low
) + 1;
5407 L_Length
:= UI_From_Int
(0);
5410 if Expr_Value
(R_High
) >= Expr_Value
(R_Low
) then
5411 R_Length
:= Expr_Value
(R_High
) -
5412 Expr_Value
(R_Low
) + 1;
5414 R_Length
:= UI_From_Int
(0);
5417 if L_Length
> R_Length
then
5419 (Compile_Time_Constraint_Error
5420 (Wnode
, "too few elements for}?", T_Typ
));
5422 elsif L_Length
< R_Length
then
5424 (Compile_Time_Constraint_Error
5425 (Wnode
, "too many elements for}?", T_Typ
));
5428 -- The comparison for an individual index subtype
5429 -- is omitted if the corresponding index subtypes
5430 -- statically match, since the result is known to
5431 -- be true. Note that this test is worth while even
5432 -- though we do static evaluation, because non-static
5433 -- subtypes can statically match.
5436 Subtypes_Statically_Match
5437 (Etype
(L_Index
), Etype
(R_Index
))
5440 (Same_Bounds
(L_Low
, R_Low
)
5441 and then Same_Bounds
(L_High
, R_High
))
5444 (Cond
, Length_E_Cond
(Exptyp
, T_Typ
, Indx
));
5453 -- Handle cases where we do not get a usable actual subtype that
5454 -- is constrained. This happens for example in the function call
5455 -- and explicit dereference cases. In these cases, we have to get
5456 -- the length or range from the expression itself, making sure we
5457 -- do not evaluate it more than once.
5459 -- Here Ck_Node is the original expression, or more properly the
5460 -- result of applying Duplicate_Expr to the original tree,
5461 -- forcing the result to be a name.
5465 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
5468 -- Build the condition for the explicit dereference case
5470 for Indx
in 1 .. Ndims
loop
5472 (Cond
, Length_N_Cond
(Ck_Node
, T_Typ
, Indx
));
5479 -- Construct the test and insert into the tree
5481 if Present
(Cond
) then
5483 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
5487 (Make_Raise_Constraint_Error
(Loc
,
5489 Reason
=> CE_Length_Check_Failed
));
5493 end Selected_Length_Checks
;
5495 ---------------------------
5496 -- Selected_Range_Checks --
5497 ---------------------------
5499 function Selected_Range_Checks
5501 Target_Typ
: Entity_Id
;
5502 Source_Typ
: Entity_Id
;
5503 Warn_Node
: Node_Id
) return Check_Result
5505 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
5508 Expr_Actual
: Node_Id
;
5510 Cond
: Node_Id
:= Empty
;
5511 Do_Access
: Boolean := False;
5512 Wnode
: Node_Id
:= Warn_Node
;
5513 Ret_Result
: Check_Result
:= (Empty
, Empty
);
5514 Num_Checks
: Integer := 0;
5516 procedure Add_Check
(N
: Node_Id
);
5517 -- Adds the action given to Ret_Result if N is non-Empty
5519 function Discrete_Range_Cond
5521 Typ
: Entity_Id
) return Node_Id
;
5522 -- Returns expression to compute:
5523 -- Low_Bound (Expr) < Typ'First
5525 -- High_Bound (Expr) > Typ'Last
5527 function Discrete_Expr_Cond
5529 Typ
: Entity_Id
) return Node_Id
;
5530 -- Returns expression to compute:
5535 function Get_E_First_Or_Last
5538 Nam
: Name_Id
) return Node_Id
;
5539 -- Returns expression to compute:
5540 -- E'First or E'Last
5542 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5543 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
5544 -- Returns expression to compute:
5545 -- N'First or N'Last using Duplicate_Subexpr_No_Checks
5547 function Range_E_Cond
5548 (Exptyp
: Entity_Id
;
5552 -- Returns expression to compute:
5553 -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
5555 function Range_Equal_E_Cond
5556 (Exptyp
: Entity_Id
;
5558 Indx
: Nat
) return Node_Id
;
5559 -- Returns expression to compute:
5560 -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
5562 function Range_N_Cond
5565 Indx
: Nat
) return Node_Id
;
5566 -- Return expression to compute:
5567 -- Expr'First < Typ'First or else Expr'Last > Typ'Last
5573 procedure Add_Check
(N
: Node_Id
) is
5577 -- For now, ignore attempt to place more than 2 checks ???
5579 if Num_Checks
= 2 then
5583 pragma Assert
(Num_Checks
<= 1);
5584 Num_Checks
:= Num_Checks
+ 1;
5585 Ret_Result
(Num_Checks
) := N
;
5589 -------------------------
5590 -- Discrete_Expr_Cond --
5591 -------------------------
5593 function Discrete_Expr_Cond
5595 Typ
: Entity_Id
) return Node_Id
5603 Convert_To
(Base_Type
(Typ
),
5604 Duplicate_Subexpr_No_Checks
(Expr
)),
5606 Convert_To
(Base_Type
(Typ
),
5607 Get_E_First_Or_Last
(Typ
, 0, Name_First
))),
5612 Convert_To
(Base_Type
(Typ
),
5613 Duplicate_Subexpr_No_Checks
(Expr
)),
5617 Get_E_First_Or_Last
(Typ
, 0, Name_Last
))));
5618 end Discrete_Expr_Cond
;
5620 -------------------------
5621 -- Discrete_Range_Cond --
5622 -------------------------
5624 function Discrete_Range_Cond
5626 Typ
: Entity_Id
) return Node_Id
5628 LB
: Node_Id
:= Low_Bound
(Expr
);
5629 HB
: Node_Id
:= High_Bound
(Expr
);
5631 Left_Opnd
: Node_Id
;
5632 Right_Opnd
: Node_Id
;
5635 if Nkind
(LB
) = N_Identifier
5636 and then Ekind
(Entity
(LB
)) = E_Discriminant
then
5637 LB
:= New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
5640 if Nkind
(HB
) = N_Identifier
5641 and then Ekind
(Entity
(HB
)) = E_Discriminant
then
5642 HB
:= New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
5649 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(LB
)),
5653 (Base_Type
(Typ
), Get_E_First_Or_Last
(Typ
, 0, Name_First
)));
5655 if Base_Type
(Typ
) = Typ
then
5658 elsif Compile_Time_Known_Value
(High_Bound
(Scalar_Range
(Typ
)))
5660 Compile_Time_Known_Value
(High_Bound
(Scalar_Range
5663 if Is_Floating_Point_Type
(Typ
) then
5664 if Expr_Value_R
(High_Bound
(Scalar_Range
(Typ
))) =
5665 Expr_Value_R
(High_Bound
(Scalar_Range
(Base_Type
(Typ
))))
5671 if Expr_Value
(High_Bound
(Scalar_Range
(Typ
))) =
5672 Expr_Value
(High_Bound
(Scalar_Range
(Base_Type
(Typ
))))
5683 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(HB
)),
5688 Get_E_First_Or_Last
(Typ
, 0, Name_Last
)));
5690 return Make_Or_Else
(Loc
, Left_Opnd
, Right_Opnd
);
5691 end Discrete_Range_Cond
;
5693 -------------------------
5694 -- Get_E_First_Or_Last --
5695 -------------------------
5697 function Get_E_First_Or_Last
5700 Nam
: Name_Id
) return Node_Id
5708 if Is_Array_Type
(E
) then
5709 N
:= First_Index
(E
);
5711 for J
in 2 .. Indx
loop
5716 N
:= Scalar_Range
(E
);
5719 if Nkind
(N
) = N_Subtype_Indication
then
5720 LB
:= Low_Bound
(Range_Expression
(Constraint
(N
)));
5721 HB
:= High_Bound
(Range_Expression
(Constraint
(N
)));
5723 elsif Is_Entity_Name
(N
) then
5724 LB
:= Type_Low_Bound
(Etype
(N
));
5725 HB
:= Type_High_Bound
(Etype
(N
));
5728 LB
:= Low_Bound
(N
);
5729 HB
:= High_Bound
(N
);
5732 if Nam
= Name_First
then
5738 if Nkind
(Bound
) = N_Identifier
5739 and then Ekind
(Entity
(Bound
)) = E_Discriminant
5741 -- If this is a task discriminant, and we are the body, we must
5742 -- retrieve the corresponding body discriminal. This is another
5743 -- consequence of the early creation of discriminals, and the
5744 -- need to generate constraint checks before their declarations
5745 -- are made visible.
5747 if Is_Concurrent_Record_Type
(Scope
(Entity
(Bound
))) then
5749 Tsk
: constant Entity_Id
:=
5750 Corresponding_Concurrent_Type
5751 (Scope
(Entity
(Bound
)));
5755 if In_Open_Scopes
(Tsk
)
5756 and then Has_Completion
(Tsk
)
5758 -- Find discriminant of original task, and use its
5759 -- current discriminal, which is the renaming within
5762 Disc
:= First_Discriminant
(Tsk
);
5763 while Present
(Disc
) loop
5764 if Chars
(Disc
) = Chars
(Entity
(Bound
)) then
5765 Set_Scope
(Discriminal
(Disc
), Tsk
);
5766 return New_Occurrence_Of
(Discriminal
(Disc
), Loc
);
5769 Next_Discriminant
(Disc
);
5772 -- That loop should always succeed in finding a matching
5773 -- entry and returning. Fatal error if not.
5775 raise Program_Error
;
5779 New_Occurrence_Of
(Discriminal
(Entity
(Bound
)), Loc
);
5783 return New_Occurrence_Of
(Discriminal
(Entity
(Bound
)), Loc
);
5786 elsif Nkind
(Bound
) = N_Identifier
5787 and then Ekind
(Entity
(Bound
)) = E_In_Parameter
5788 and then not Inside_Init_Proc
5790 return Get_Discriminal
(E
, Bound
);
5792 elsif Nkind
(Bound
) = N_Integer_Literal
then
5793 return Make_Integer_Literal
(Loc
, Intval
(Bound
));
5795 -- Case of a bound that has been rewritten to an
5796 -- N_Raise_Constraint_Error node because it is an out-of-range
5797 -- value. We may not call Duplicate_Subexpr on this node because
5798 -- an N_Raise_Constraint_Error is not side effect free, and we may
5799 -- not assume that we are in the proper context to remove side
5800 -- effects on it at the point of reference.
5802 elsif Nkind
(Bound
) = N_Raise_Constraint_Error
then
5803 return New_Copy_Tree
(Bound
);
5806 return Duplicate_Subexpr_No_Checks
(Bound
);
5808 end Get_E_First_Or_Last
;
5814 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5817 Make_Attribute_Reference
(Loc
,
5818 Attribute_Name
=> Name_First
,
5820 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5821 Expressions
=> New_List
(
5822 Make_Integer_Literal
(Loc
, Indx
)));
5829 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
5832 Make_Attribute_Reference
(Loc
,
5833 Attribute_Name
=> Name_Last
,
5835 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
5836 Expressions
=> New_List
(
5837 Make_Integer_Literal
(Loc
, Indx
)));
5844 function Range_E_Cond
5845 (Exptyp
: Entity_Id
;
5847 Indx
: Nat
) return Node_Id
5854 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_First
),
5855 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5859 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_Last
),
5860 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5864 ------------------------
5865 -- Range_Equal_E_Cond --
5866 ------------------------
5868 function Range_Equal_E_Cond
5869 (Exptyp
: Entity_Id
;
5871 Indx
: Nat
) return Node_Id
5878 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_First
),
5879 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5882 Left_Opnd
=> Get_E_First_Or_Last
(Exptyp
, Indx
, Name_Last
),
5883 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5884 end Range_Equal_E_Cond
;
5890 function Range_N_Cond
5893 Indx
: Nat
) return Node_Id
5900 Left_Opnd
=> Get_N_First
(Expr
, Indx
),
5901 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_First
)),
5905 Left_Opnd
=> Get_N_Last
(Expr
, Indx
),
5906 Right_Opnd
=> Get_E_First_Or_Last
(Typ
, Indx
, Name_Last
)));
5909 -- Start of processing for Selected_Range_Checks
5912 if not Expander_Active
then
5916 if Target_Typ
= Any_Type
5917 or else Target_Typ
= Any_Composite
5918 or else Raises_Constraint_Error
(Ck_Node
)
5927 T_Typ
:= Target_Typ
;
5929 if No
(Source_Typ
) then
5930 S_Typ
:= Etype
(Ck_Node
);
5932 S_Typ
:= Source_Typ
;
5935 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
5939 -- The order of evaluating T_Typ before S_Typ seems to be critical
5940 -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
5941 -- in, and since Node can be an N_Range node, it might be invalid.
5942 -- Should there be an assert check somewhere for taking the Etype of
5943 -- an N_Range node ???
5945 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
5946 S_Typ
:= Designated_Type
(S_Typ
);
5947 T_Typ
:= Designated_Type
(T_Typ
);
5950 -- A simple optimization
5952 if Nkind
(Ck_Node
) = N_Null
then
5957 -- For an N_Range Node, check for a null range and then if not
5958 -- null generate a range check action.
5960 if Nkind
(Ck_Node
) = N_Range
then
5962 -- There's no point in checking a range against itself
5964 if Ck_Node
= Scalar_Range
(T_Typ
) then
5969 T_LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
5970 T_HB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
5971 LB
: constant Node_Id
:= Low_Bound
(Ck_Node
);
5972 HB
: constant Node_Id
:= High_Bound
(Ck_Node
);
5973 Null_Range
: Boolean;
5975 Out_Of_Range_L
: Boolean;
5976 Out_Of_Range_H
: Boolean;
5979 -- Check for case where everything is static and we can
5980 -- do the check at compile time. This is skipped if we
5981 -- have an access type, since the access value may be null.
5983 -- ??? This code can be improved since you only need to know
5984 -- that the two respective bounds (LB & T_LB or HB & T_HB)
5985 -- are known at compile time to emit pertinent messages.
5987 if Compile_Time_Known_Value
(LB
)
5988 and then Compile_Time_Known_Value
(HB
)
5989 and then Compile_Time_Known_Value
(T_LB
)
5990 and then Compile_Time_Known_Value
(T_HB
)
5991 and then not Do_Access
5993 -- Floating-point case
5995 if Is_Floating_Point_Type
(S_Typ
) then
5996 Null_Range
:= Expr_Value_R
(HB
) < Expr_Value_R
(LB
);
5998 (Expr_Value_R
(LB
) < Expr_Value_R
(T_LB
))
6000 (Expr_Value_R
(LB
) > Expr_Value_R
(T_HB
));
6003 (Expr_Value_R
(HB
) > Expr_Value_R
(T_HB
))
6005 (Expr_Value_R
(HB
) < Expr_Value_R
(T_LB
));
6007 -- Fixed or discrete type case
6010 Null_Range
:= Expr_Value
(HB
) < Expr_Value
(LB
);
6012 (Expr_Value
(LB
) < Expr_Value
(T_LB
))
6014 (Expr_Value
(LB
) > Expr_Value
(T_HB
));
6017 (Expr_Value
(HB
) > Expr_Value
(T_HB
))
6019 (Expr_Value
(HB
) < Expr_Value
(T_LB
));
6022 if not Null_Range
then
6023 if Out_Of_Range_L
then
6024 if No
(Warn_Node
) then
6026 (Compile_Time_Constraint_Error
6027 (Low_Bound
(Ck_Node
),
6028 "static value out of range of}?", T_Typ
));
6032 (Compile_Time_Constraint_Error
6034 "static range out of bounds of}?", T_Typ
));
6038 if Out_Of_Range_H
then
6039 if No
(Warn_Node
) then
6041 (Compile_Time_Constraint_Error
6042 (High_Bound
(Ck_Node
),
6043 "static value out of range of}?", T_Typ
));
6047 (Compile_Time_Constraint_Error
6049 "static range out of bounds of}?", T_Typ
));
6057 LB
: Node_Id
:= Low_Bound
(Ck_Node
);
6058 HB
: Node_Id
:= High_Bound
(Ck_Node
);
6062 -- If either bound is a discriminant and we are within
6063 -- the record declaration, it is a use of the discriminant
6064 -- in a constraint of a component, and nothing can be
6065 -- checked here. The check will be emitted within the
6066 -- init proc. Before then, the discriminal has no real
6069 if Nkind
(LB
) = N_Identifier
6070 and then Ekind
(Entity
(LB
)) = E_Discriminant
6072 if Current_Scope
= Scope
(Entity
(LB
)) then
6076 New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
6080 if Nkind
(HB
) = N_Identifier
6081 and then Ekind
(Entity
(HB
)) = E_Discriminant
6083 if Current_Scope
= Scope
(Entity
(HB
)) then
6087 New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
6091 Cond
:= Discrete_Range_Cond
(Ck_Node
, T_Typ
);
6092 Set_Paren_Count
(Cond
, 1);
6098 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(HB
),
6099 Right_Opnd
=> Duplicate_Subexpr_No_Checks
(LB
)),
6100 Right_Opnd
=> Cond
);
6106 elsif Is_Scalar_Type
(S_Typ
) then
6108 -- This somewhat duplicates what Apply_Scalar_Range_Check does,
6109 -- except the above simply sets a flag in the node and lets
6110 -- gigi generate the check base on the Etype of the expression.
6111 -- Sometimes, however we want to do a dynamic check against an
6112 -- arbitrary target type, so we do that here.
6114 if Ekind
(Base_Type
(S_Typ
)) /= Ekind
(Base_Type
(T_Typ
)) then
6115 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6117 -- For literals, we can tell if the constraint error will be
6118 -- raised at compile time, so we never need a dynamic check, but
6119 -- if the exception will be raised, then post the usual warning,
6120 -- and replace the literal with a raise constraint error
6121 -- expression. As usual, skip this for access types
6123 elsif Compile_Time_Known_Value
(Ck_Node
)
6124 and then not Do_Access
6127 LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
6128 UB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
6130 Out_Of_Range
: Boolean;
6131 Static_Bounds
: constant Boolean :=
6132 Compile_Time_Known_Value
(LB
)
6133 and Compile_Time_Known_Value
(UB
);
6136 -- Following range tests should use Sem_Eval routine ???
6138 if Static_Bounds
then
6139 if Is_Floating_Point_Type
(S_Typ
) then
6141 (Expr_Value_R
(Ck_Node
) < Expr_Value_R
(LB
))
6143 (Expr_Value_R
(Ck_Node
) > Expr_Value_R
(UB
));
6145 else -- fixed or discrete type
6147 Expr_Value
(Ck_Node
) < Expr_Value
(LB
)
6149 Expr_Value
(Ck_Node
) > Expr_Value
(UB
);
6152 -- Bounds of the type are static and the literal is
6153 -- out of range so make a warning message.
6155 if Out_Of_Range
then
6156 if No
(Warn_Node
) then
6158 (Compile_Time_Constraint_Error
6160 "static value out of range of}?", T_Typ
));
6164 (Compile_Time_Constraint_Error
6166 "static value out of range of}?", T_Typ
));
6171 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6175 -- Here for the case of a non-static expression, we need a runtime
6176 -- check unless the source type range is guaranteed to be in the
6177 -- range of the target type.
6180 if not In_Subrange_Of
(S_Typ
, T_Typ
) then
6181 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
6186 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
6187 if Is_Constrained
(T_Typ
) then
6189 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
6190 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
6192 if Is_Access_Type
(Exptyp
) then
6193 Exptyp
:= Designated_Type
(Exptyp
);
6196 -- String_Literal case. This needs to be handled specially be-
6197 -- cause no index types are available for string literals. The
6198 -- condition is simply:
6200 -- T_Typ'Length = string-literal-length
6202 if Nkind
(Expr_Actual
) = N_String_Literal
then
6205 -- General array case. Here we have a usable actual subtype for
6206 -- the expression, and the condition is built from the two types
6208 -- T_Typ'First < Exptyp'First or else
6209 -- T_Typ'Last > Exptyp'Last or else
6210 -- T_Typ'First(1) < Exptyp'First(1) or else
6211 -- T_Typ'Last(1) > Exptyp'Last(1) or else
6214 elsif Is_Constrained
(Exptyp
) then
6216 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
6226 L_Index
:= First_Index
(T_Typ
);
6227 R_Index
:= First_Index
(Exptyp
);
6229 for Indx
in 1 .. Ndims
loop
6230 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
6232 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
6234 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
6235 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
6237 -- Deal with compile time length check. Note that we
6238 -- skip this in the access case, because the access
6239 -- value may be null, so we cannot know statically.
6242 Subtypes_Statically_Match
6243 (Etype
(L_Index
), Etype
(R_Index
))
6245 -- If the target type is constrained then we
6246 -- have to check for exact equality of bounds
6247 -- (required for qualified expressions).
6249 if Is_Constrained
(T_Typ
) then
6252 Range_Equal_E_Cond
(Exptyp
, T_Typ
, Indx
));
6256 (Cond
, Range_E_Cond
(Exptyp
, T_Typ
, Indx
));
6267 -- Handle cases where we do not get a usable actual subtype that
6268 -- is constrained. This happens for example in the function call
6269 -- and explicit dereference cases. In these cases, we have to get
6270 -- the length or range from the expression itself, making sure we
6271 -- do not evaluate it more than once.
6273 -- Here Ck_Node is the original expression, or more properly the
6274 -- result of applying Duplicate_Expr to the original tree,
6275 -- forcing the result to be a name.
6279 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
6282 -- Build the condition for the explicit dereference case
6284 for Indx
in 1 .. Ndims
loop
6286 (Cond
, Range_N_Cond
(Ck_Node
, T_Typ
, Indx
));
6293 -- Generate an Action to check that the bounds of the
6294 -- source value are within the constraints imposed by the
6295 -- target type for a conversion to an unconstrained type.
6298 if Nkind
(Parent
(Ck_Node
)) = N_Type_Conversion
then
6300 Opnd_Index
: Node_Id
;
6301 Targ_Index
: Node_Id
;
6305 := First_Index
(Get_Actual_Subtype
(Ck_Node
));
6306 Targ_Index
:= First_Index
(T_Typ
);
6308 while Opnd_Index
/= Empty
loop
6309 if Nkind
(Opnd_Index
) = N_Range
then
6311 (Low_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6314 (High_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6318 -- If null range, no check needed
6321 Compile_Time_Known_Value
(High_Bound
(Opnd_Index
))
6323 Compile_Time_Known_Value
(Low_Bound
(Opnd_Index
))
6325 Expr_Value
(High_Bound
(Opnd_Index
)) <
6326 Expr_Value
(Low_Bound
(Opnd_Index
))
6330 elsif Is_Out_Of_Range
6331 (Low_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6334 (High_Bound
(Opnd_Index
), Etype
(Targ_Index
))
6337 (Compile_Time_Constraint_Error
6338 (Wnode
, "value out of range of}?", T_Typ
));
6344 (Opnd_Index
, Etype
(Targ_Index
)));
6348 Next_Index
(Opnd_Index
);
6349 Next_Index
(Targ_Index
);
6356 -- Construct the test and insert into the tree
6358 if Present
(Cond
) then
6360 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
6364 (Make_Raise_Constraint_Error
(Loc
,
6366 Reason
=> CE_Range_Check_Failed
));
6370 end Selected_Range_Checks
;
6372 -------------------------------
6373 -- Storage_Checks_Suppressed --
6374 -------------------------------
6376 function Storage_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6378 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
6379 return Is_Check_Suppressed
(E
, Storage_Check
);
6381 return Scope_Suppress
(Storage_Check
);
6383 end Storage_Checks_Suppressed
;
6385 ---------------------------
6386 -- Tag_Checks_Suppressed --
6387 ---------------------------
6389 function Tag_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
6392 if Kill_Tag_Checks
(E
) then
6394 elsif Checks_May_Be_Suppressed
(E
) then
6395 return Is_Check_Suppressed
(E
, Tag_Check
);
6399 return Scope_Suppress
(Tag_Check
);
6400 end Tag_Checks_Suppressed
;