1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2018, 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 3, 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 COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree
; use Atree
;
27 with Casing
; use Casing
;
28 with Debug
; use Debug
;
29 with Einfo
; use Einfo
;
30 with Elists
; use Elists
;
31 with Eval_Fat
; use Eval_Fat
;
32 with Exp_Ch11
; use Exp_Ch11
;
33 with Exp_Ch2
; use Exp_Ch2
;
34 with Exp_Ch4
; use Exp_Ch4
;
35 with Exp_Pakd
; use Exp_Pakd
;
36 with Exp_Util
; use Exp_Util
;
37 with Expander
; use Expander
;
38 with Freeze
; use Freeze
;
40 with Nlists
; use Nlists
;
41 with Nmake
; use Nmake
;
43 with Output
; use Output
;
44 with Restrict
; use Restrict
;
45 with Rident
; use Rident
;
46 with Rtsfind
; use Rtsfind
;
48 with Sem_Aux
; use Sem_Aux
;
49 with Sem_Ch3
; use Sem_Ch3
;
50 with Sem_Ch8
; use Sem_Ch8
;
51 with Sem_Disp
; use Sem_Disp
;
52 with Sem_Eval
; use Sem_Eval
;
53 with Sem_Res
; use Sem_Res
;
54 with Sem_Util
; use Sem_Util
;
55 with Sem_Warn
; use Sem_Warn
;
56 with Sinfo
; use Sinfo
;
57 with Sinput
; use Sinput
;
58 with Snames
; use Snames
;
59 with Sprint
; use Sprint
;
60 with Stand
; use Stand
;
61 with Stringt
; use Stringt
;
62 with Targparm
; use Targparm
;
63 with Tbuild
; use Tbuild
;
64 with Ttypes
; use Ttypes
;
65 with Validsw
; use Validsw
;
67 package body Checks
is
69 -- General note: many of these routines are concerned with generating
70 -- checking code to make sure that constraint error is raised at runtime.
71 -- Clearly this code is only needed if the expander is active, since
72 -- otherwise we will not be generating code or going into the runtime
75 -- We therefore disconnect most of these checks if the expander is
76 -- inactive. This has the additional benefit that we do not need to
77 -- worry about the tree being messed up by previous errors (since errors
78 -- turn off expansion anyway).
80 -- There are a few exceptions to the above rule. For instance routines
81 -- such as Apply_Scalar_Range_Check that do not insert any code can be
82 -- safely called even when the Expander is inactive (but Errors_Detected
83 -- is 0). The benefit of executing this code when expansion is off, is
84 -- the ability to emit constraint error warning for static expressions
85 -- even when we are not generating code.
87 -- The above is modified in gnatprove mode to ensure that proper check
88 -- flags are always placed, even if expansion is off.
90 -------------------------------------
91 -- Suppression of Redundant Checks --
92 -------------------------------------
94 -- This unit implements a limited circuit for removal of redundant
95 -- checks. The processing is based on a tracing of simple sequential
96 -- flow. For any sequence of statements, we save expressions that are
97 -- marked to be checked, and then if the same expression appears later
98 -- with the same check, then under certain circumstances, the second
99 -- check can be suppressed.
101 -- Basically, we can suppress the check if we know for certain that
102 -- the previous expression has been elaborated (together with its
103 -- check), and we know that the exception frame is the same, and that
104 -- nothing has happened to change the result of the exception.
106 -- Let us examine each of these three conditions in turn to describe
107 -- how we ensure that this condition is met.
109 -- First, we need to know for certain that the previous expression has
110 -- been executed. This is done principally by the mechanism of calling
111 -- Conditional_Statements_Begin at the start of any statement sequence
112 -- and Conditional_Statements_End at the end. The End call causes all
113 -- checks remembered since the Begin call to be discarded. This does
114 -- miss a few cases, notably the case of a nested BEGIN-END block with
115 -- no exception handlers. But the important thing is to be conservative.
116 -- The other protection is that all checks are discarded if a label
117 -- is encountered, since then the assumption of sequential execution
118 -- is violated, and we don't know enough about the flow.
120 -- Second, we need to know that the exception frame is the same. We
121 -- do this by killing all remembered checks when we enter a new frame.
122 -- Again, that's over-conservative, but generally the cases we can help
123 -- with are pretty local anyway (like the body of a loop for example).
125 -- Third, we must be sure to forget any checks which are no longer valid.
126 -- This is done by two mechanisms, first the Kill_Checks_Variable call is
127 -- used to note any changes to local variables. We only attempt to deal
128 -- with checks involving local variables, so we do not need to worry
129 -- about global variables. Second, a call to any non-global procedure
130 -- causes us to abandon all stored checks, since such a all may affect
131 -- the values of any local variables.
133 -- The following define the data structures used to deal with remembering
134 -- checks so that redundant checks can be eliminated as described above.
136 -- Right now, the only expressions that we deal with are of the form of
137 -- simple local objects (either declared locally, or IN parameters) or
138 -- such objects plus/minus a compile time known constant. We can do
139 -- more later on if it seems worthwhile, but this catches many simple
140 -- cases in practice.
142 -- The following record type reflects a single saved check. An entry
143 -- is made in the stack of saved checks if and only if the expression
144 -- has been elaborated with the indicated checks.
146 type Saved_Check
is record
148 -- Set True if entry is killed by Kill_Checks
151 -- The entity involved in the expression that is checked
154 -- A compile time value indicating the result of adding or
155 -- subtracting a compile time value. This value is to be
156 -- added to the value of the Entity. A value of zero is
157 -- used for the case of a simple entity reference.
159 Check_Type
: Character;
160 -- This is set to 'R' for a range check (in which case Target_Type
161 -- is set to the target type for the range check) or to 'O' for an
162 -- overflow check (in which case Target_Type is set to Empty).
164 Target_Type
: Entity_Id
;
165 -- Used only if Do_Range_Check is set. Records the target type for
166 -- the check. We need this, because a check is a duplicate only if
167 -- it has the same target type (or more accurately one with a
168 -- range that is smaller or equal to the stored target type of a
172 -- The following table keeps track of saved checks. Rather than use an
173 -- extensible table, we just use a table of fixed size, and we discard
174 -- any saved checks that do not fit. That's very unlikely to happen and
175 -- this is only an optimization in any case.
177 Saved_Checks
: array (Int
range 1 .. 200) of Saved_Check
;
178 -- Array of saved checks
180 Num_Saved_Checks
: Nat
:= 0;
181 -- Number of saved checks
183 -- The following stack keeps track of statement ranges. It is treated
184 -- as a stack. When Conditional_Statements_Begin is called, an entry
185 -- is pushed onto this stack containing the value of Num_Saved_Checks
186 -- at the time of the call. Then when Conditional_Statements_End is
187 -- called, this value is popped off and used to reset Num_Saved_Checks.
189 -- Note: again, this is a fixed length stack with a size that should
190 -- always be fine. If the value of the stack pointer goes above the
191 -- limit, then we just forget all saved checks.
193 Saved_Checks_Stack
: array (Int
range 1 .. 100) of Nat
;
194 Saved_Checks_TOS
: Nat
:= 0;
196 -----------------------
197 -- Local Subprograms --
198 -----------------------
200 procedure Apply_Arithmetic_Overflow_Strict
(N
: Node_Id
);
201 -- Used to apply arithmetic overflow checks for all cases except operators
202 -- on signed arithmetic types in MINIMIZED/ELIMINATED case (for which we
203 -- call Apply_Arithmetic_Overflow_Minimized_Eliminated below). N can be a
204 -- signed integer arithmetic operator (but not an if or case expression).
205 -- It is also called for types other than signed integers.
207 procedure Apply_Arithmetic_Overflow_Minimized_Eliminated
(Op
: Node_Id
);
208 -- Used to apply arithmetic overflow checks for the case where the overflow
209 -- checking mode is MINIMIZED or ELIMINATED and we have a signed integer
210 -- arithmetic op (which includes the case of if and case expressions). Note
211 -- that Do_Overflow_Check may or may not be set for node Op. In these modes
212 -- we have work to do even if overflow checking is suppressed.
214 procedure Apply_Division_Check
219 -- N is an N_Op_Div, N_Op_Rem, or N_Op_Mod node. This routine applies
220 -- division checks as required if the Do_Division_Check flag is set.
221 -- Rlo and Rhi give the possible range of the right operand, these values
222 -- can be referenced and trusted only if ROK is set True.
224 procedure Apply_Float_Conversion_Check
226 Target_Typ
: Entity_Id
);
227 -- The checks on a conversion from a floating-point type to an integer
228 -- type are delicate. They have to be performed before conversion, they
229 -- have to raise an exception when the operand is a NaN, and rounding must
230 -- be taken into account to determine the safe bounds of the operand.
232 procedure Apply_Selected_Length_Checks
234 Target_Typ
: Entity_Id
;
235 Source_Typ
: Entity_Id
;
236 Do_Static
: Boolean);
237 -- This is the subprogram that does all the work for Apply_Length_Check
238 -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as
239 -- described for the above routines. The Do_Static flag indicates that
240 -- only a static check is to be done.
242 procedure Apply_Selected_Range_Checks
244 Target_Typ
: Entity_Id
;
245 Source_Typ
: Entity_Id
;
246 Do_Static
: Boolean);
247 -- This is the subprogram that does all the work for Apply_Range_Check.
248 -- Expr, Target_Typ and Source_Typ are as described for the above
249 -- routine. The Do_Static flag indicates that only a static check is
252 type Check_Type
is new Check_Id
range Access_Check
.. Division_Check
;
253 function Check_Needed
(Nod
: Node_Id
; Check
: Check_Type
) return Boolean;
254 -- This function is used to see if an access or division by zero check is
255 -- needed. The check is to be applied to a single variable appearing in the
256 -- source, and N is the node for the reference. If N is not of this form,
257 -- True is returned with no further processing. If N is of the right form,
258 -- then further processing determines if the given Check is needed.
260 -- The particular circuit is to see if we have the case of a check that is
261 -- not needed because it appears in the right operand of a short circuited
262 -- conditional where the left operand guards the check. For example:
264 -- if Var = 0 or else Q / Var > 12 then
268 -- In this example, the division check is not required. At the same time
269 -- we can issue warnings for suspicious use of non-short-circuited forms,
272 -- if Var = 0 or Q / Var > 12 then
278 Check_Type
: Character;
279 Target_Type
: Entity_Id
;
280 Entry_OK
: out Boolean;
284 -- This routine is used by Enable_Range_Check and Enable_Overflow_Check
285 -- to see if a check is of the form for optimization, and if so, to see
286 -- if it has already been performed. Expr is the expression to check,
287 -- and Check_Type is 'R' for a range check, 'O' for an overflow check.
288 -- Target_Type is the target type for a range check, and Empty for an
289 -- overflow check. If the entry is not of the form for optimization,
290 -- then Entry_OK is set to False, and the remaining out parameters
291 -- are undefined. If the entry is OK, then Ent/Ofs are set to the
292 -- entity and offset from the expression. Check_Num is the number of
293 -- a matching saved entry in Saved_Checks, or zero if no such entry
296 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
;
297 -- If a discriminal is used in constraining a prival, Return reference
298 -- to the discriminal of the protected body (which renames the parameter
299 -- of the enclosing protected operation). This clumsy transformation is
300 -- needed because privals are created too late and their actual subtypes
301 -- are not available when analysing the bodies of the protected operations.
302 -- This function is called whenever the bound is an entity and the scope
303 -- indicates a protected operation. If the bound is an in-parameter of
304 -- a protected operation that is not a prival, the function returns the
306 -- To be cleaned up???
308 function Guard_Access
311 Ck_Node
: Node_Id
) return Node_Id
;
312 -- In the access type case, guard the test with a test to ensure
313 -- that the access value is non-null, since the checks do not
314 -- not apply to null access values.
316 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
);
317 -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the
318 -- Constraint_Error node.
320 function Is_Signed_Integer_Arithmetic_Op
(N
: Node_Id
) return Boolean;
321 -- Returns True if node N is for an arithmetic operation with signed
322 -- integer operands. This includes unary and binary operators, and also
323 -- if and case expression nodes where the dependent expressions are of
324 -- a signed integer type. These are the kinds of nodes for which special
325 -- handling applies in MINIMIZED or ELIMINATED overflow checking mode.
327 function Range_Or_Validity_Checks_Suppressed
328 (Expr
: Node_Id
) return Boolean;
329 -- Returns True if either range or validity checks or both are suppressed
330 -- for the type of the given expression, or, if the expression is the name
331 -- of an entity, if these checks are suppressed for the entity.
333 function Selected_Length_Checks
335 Target_Typ
: Entity_Id
;
336 Source_Typ
: Entity_Id
;
337 Warn_Node
: Node_Id
) return Check_Result
;
338 -- Like Apply_Selected_Length_Checks, except it doesn't modify
339 -- anything, just returns a list of nodes as described in the spec of
340 -- this package for the Range_Check function.
341 -- ??? In fact it does construct the test and insert it into the tree,
342 -- and insert actions in various ways (calling Insert_Action directly
343 -- in particular) so we do not call it in GNATprove mode, contrary to
344 -- Selected_Range_Checks.
346 function Selected_Range_Checks
348 Target_Typ
: Entity_Id
;
349 Source_Typ
: Entity_Id
;
350 Warn_Node
: Node_Id
) return Check_Result
;
351 -- Like Apply_Selected_Range_Checks, except it doesn't modify anything,
352 -- just returns a list of nodes as described in the spec of this package
353 -- for the Range_Check function.
355 ------------------------------
356 -- Access_Checks_Suppressed --
357 ------------------------------
359 function Access_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
361 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
362 return Is_Check_Suppressed
(E
, Access_Check
);
364 return Scope_Suppress
.Suppress
(Access_Check
);
366 end Access_Checks_Suppressed
;
368 -------------------------------------
369 -- Accessibility_Checks_Suppressed --
370 -------------------------------------
372 function Accessibility_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
374 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
375 return Is_Check_Suppressed
(E
, Accessibility_Check
);
377 return Scope_Suppress
.Suppress
(Accessibility_Check
);
379 end Accessibility_Checks_Suppressed
;
381 -----------------------------
382 -- Activate_Division_Check --
383 -----------------------------
385 procedure Activate_Division_Check
(N
: Node_Id
) is
387 Set_Do_Division_Check
(N
, True);
388 Possible_Local_Raise
(N
, Standard_Constraint_Error
);
389 end Activate_Division_Check
;
391 -----------------------------
392 -- Activate_Overflow_Check --
393 -----------------------------
395 procedure Activate_Overflow_Check
(N
: Node_Id
) is
396 Typ
: constant Entity_Id
:= Etype
(N
);
399 -- Floating-point case. If Etype is not set (this can happen when we
400 -- activate a check on a node that has not yet been analyzed), then
401 -- we assume we do not have a floating-point type (as per our spec).
403 if Present
(Typ
) and then Is_Floating_Point_Type
(Typ
) then
405 -- Ignore call if we have no automatic overflow checks on the target
406 -- and Check_Float_Overflow mode is not set. These are the cases in
407 -- which we expect to generate infinities and NaN's with no check.
409 if not (Machine_Overflows_On_Target
or Check_Float_Overflow
) then
412 -- Ignore for unary operations ("+", "-", abs) since these can never
413 -- result in overflow for floating-point cases.
415 elsif Nkind
(N
) in N_Unary_Op
then
418 -- Otherwise we will set the flag
427 -- Nothing to do for Rem/Mod/Plus (overflow not possible, the check
428 -- for zero-divide is a divide check, not an overflow check).
430 if Nkind_In
(N
, N_Op_Rem
, N_Op_Mod
, N_Op_Plus
) then
435 -- Fall through for cases where we do set the flag
437 Set_Do_Overflow_Check
(N
, True);
438 Possible_Local_Raise
(N
, Standard_Constraint_Error
);
439 end Activate_Overflow_Check
;
441 --------------------------
442 -- Activate_Range_Check --
443 --------------------------
445 procedure Activate_Range_Check
(N
: Node_Id
) is
447 Set_Do_Range_Check
(N
, True);
448 Possible_Local_Raise
(N
, Standard_Constraint_Error
);
449 end Activate_Range_Check
;
451 ---------------------------------
452 -- Alignment_Checks_Suppressed --
453 ---------------------------------
455 function Alignment_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
457 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
458 return Is_Check_Suppressed
(E
, Alignment_Check
);
460 return Scope_Suppress
.Suppress
(Alignment_Check
);
462 end Alignment_Checks_Suppressed
;
464 ----------------------------------
465 -- Allocation_Checks_Suppressed --
466 ----------------------------------
468 -- Note: at the current time there are no calls to this function, because
469 -- the relevant check is in the run-time, so it is not a check that the
470 -- compiler can suppress anyway, but we still have to recognize the check
471 -- name Allocation_Check since it is part of the standard.
473 function Allocation_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
475 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
476 return Is_Check_Suppressed
(E
, Allocation_Check
);
478 return Scope_Suppress
.Suppress
(Allocation_Check
);
480 end Allocation_Checks_Suppressed
;
482 -------------------------
483 -- Append_Range_Checks --
484 -------------------------
486 procedure Append_Range_Checks
487 (Checks
: Check_Result
;
489 Suppress_Typ
: Entity_Id
;
490 Static_Sloc
: Source_Ptr
;
493 Checks_On
: constant Boolean :=
494 not Index_Checks_Suppressed
(Suppress_Typ
)
496 not Range_Checks_Suppressed
(Suppress_Typ
);
498 Internal_Flag_Node
: constant Node_Id
:= Flag_Node
;
499 Internal_Static_Sloc
: constant Source_Ptr
:= Static_Sloc
;
502 -- For now we just return if Checks_On is false, however this should be
503 -- enhanced to check for an always True value in the condition and to
504 -- generate a compilation warning???
506 if not Checks_On
then
511 exit when No
(Checks
(J
));
513 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
514 and then Present
(Condition
(Checks
(J
)))
516 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
517 Append_To
(Stmts
, Checks
(J
));
518 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
524 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
525 Reason
=> CE_Range_Check_Failed
));
528 end Append_Range_Checks
;
530 ------------------------
531 -- Apply_Access_Check --
532 ------------------------
534 procedure Apply_Access_Check
(N
: Node_Id
) is
535 P
: constant Node_Id
:= Prefix
(N
);
538 -- We do not need checks if we are not generating code (i.e. the
539 -- expander is not active). This is not just an optimization, there
540 -- are cases (e.g. with pragma Debug) where generating the checks
541 -- can cause real trouble).
543 if not Expander_Active
then
547 -- No check if short circuiting makes check unnecessary
549 if not Check_Needed
(P
, Access_Check
) then
553 -- No check if accessing the Offset_To_Top component of a dispatch
554 -- table. They are safe by construction.
556 if Tagged_Type_Expansion
557 and then Present
(Etype
(P
))
558 and then RTU_Loaded
(Ada_Tags
)
559 and then RTE_Available
(RE_Offset_To_Top_Ptr
)
560 and then Etype
(P
) = RTE
(RE_Offset_To_Top_Ptr
)
565 -- Otherwise go ahead and install the check
567 Install_Null_Excluding_Check
(P
);
568 end Apply_Access_Check
;
570 -------------------------------
571 -- Apply_Accessibility_Check --
572 -------------------------------
574 procedure Apply_Accessibility_Check
577 Insert_Node
: Node_Id
)
579 Loc
: constant Source_Ptr
:= Sloc
(N
);
580 Param_Ent
: Entity_Id
:= Param_Entity
(N
);
581 Param_Level
: Node_Id
;
582 Type_Level
: Node_Id
;
585 if Ada_Version
>= Ada_2012
586 and then not Present
(Param_Ent
)
587 and then Is_Entity_Name
(N
)
588 and then Ekind_In
(Entity
(N
), E_Constant
, E_Variable
)
589 and then Present
(Effective_Extra_Accessibility
(Entity
(N
)))
591 Param_Ent
:= Entity
(N
);
592 while Present
(Renamed_Object
(Param_Ent
)) loop
594 -- Renamed_Object must return an Entity_Name here
595 -- because of preceding "Present (E_E_A (...))" test.
597 Param_Ent
:= Entity
(Renamed_Object
(Param_Ent
));
601 if Inside_A_Generic
then
604 -- Only apply the run-time check if the access parameter has an
605 -- associated extra access level parameter and when the level of the
606 -- type is less deep than the level of the access parameter, and
607 -- accessibility checks are not suppressed.
609 elsif Present
(Param_Ent
)
610 and then Present
(Extra_Accessibility
(Param_Ent
))
611 and then UI_Gt
(Object_Access_Level
(N
),
612 Deepest_Type_Access_Level
(Typ
))
613 and then not Accessibility_Checks_Suppressed
(Param_Ent
)
614 and then not Accessibility_Checks_Suppressed
(Typ
)
617 New_Occurrence_Of
(Extra_Accessibility
(Param_Ent
), Loc
);
620 Make_Integer_Literal
(Loc
, Deepest_Type_Access_Level
(Typ
));
622 -- Raise Program_Error if the accessibility level of the access
623 -- parameter is deeper than the level of the target access type.
625 Insert_Action
(Insert_Node
,
626 Make_Raise_Program_Error
(Loc
,
629 Left_Opnd
=> Param_Level
,
630 Right_Opnd
=> Type_Level
),
631 Reason
=> PE_Accessibility_Check_Failed
));
633 Analyze_And_Resolve
(N
);
635 end Apply_Accessibility_Check
;
637 --------------------------------
638 -- Apply_Address_Clause_Check --
639 --------------------------------
641 procedure Apply_Address_Clause_Check
(E
: Entity_Id
; N
: Node_Id
) is
642 pragma Assert
(Nkind
(N
) = N_Freeze_Entity
);
644 AC
: constant Node_Id
:= Address_Clause
(E
);
645 Loc
: constant Source_Ptr
:= Sloc
(AC
);
646 Typ
: constant Entity_Id
:= Etype
(E
);
649 -- Address expression (not necessarily the same as Aexp, for example
650 -- when Aexp is a reference to a constant, in which case Expr gets
651 -- reset to reference the value expression of the constant).
654 -- See if alignment check needed. Note that we never need a check if the
655 -- maximum alignment is one, since the check will always succeed.
657 -- Note: we do not check for checks suppressed here, since that check
658 -- was done in Sem_Ch13 when the address clause was processed. We are
659 -- only called if checks were not suppressed. The reason for this is
660 -- that we have to delay the call to Apply_Alignment_Check till freeze
661 -- time (so that all types etc are elaborated), but we have to check
662 -- the status of check suppressing at the point of the address clause.
665 or else not Check_Address_Alignment
(AC
)
666 or else Maximum_Alignment
= 1
671 -- Obtain expression from address clause
673 Expr
:= Address_Value
(Expression
(AC
));
675 -- See if we know that Expr has an acceptable value at compile time. If
676 -- it hasn't or we don't know, we defer issuing the warning until the
677 -- end of the compilation to take into account back end annotations.
679 if Compile_Time_Known_Value
(Expr
)
680 and then (Known_Alignment
(E
) or else Known_Alignment
(Typ
))
683 AL
: Uint
:= Alignment
(Typ
);
686 -- The object alignment might be more restrictive than the type
689 if Known_Alignment
(E
) then
693 if Expr_Value
(Expr
) mod AL
= 0 then
698 -- If the expression has the form X'Address, then we can find out if the
699 -- object X has an alignment that is compatible with the object E. If it
700 -- hasn't or we don't know, we defer issuing the warning until the end
701 -- of the compilation to take into account back end annotations.
703 elsif Nkind
(Expr
) = N_Attribute_Reference
704 and then Attribute_Name
(Expr
) = Name_Address
706 Has_Compatible_Alignment
(E
, Prefix
(Expr
), False) = Known_Compatible
711 -- Here we do not know if the value is acceptable. Strictly we don't
712 -- have to do anything, since if the alignment is bad, we have an
713 -- erroneous program. However we are allowed to check for erroneous
714 -- conditions and we decide to do this by default if the check is not
717 -- However, don't do the check if elaboration code is unwanted
719 if Restriction_Active
(No_Elaboration_Code
) then
722 -- Generate a check to raise PE if alignment may be inappropriate
725 -- If the original expression is a non-static constant, use the name
726 -- of the constant itself rather than duplicating its initialization
727 -- expression, which was extracted above.
729 -- Note: Expr is empty if the address-clause is applied to in-mode
730 -- actuals (allowed by 13.1(22)).
732 if not Present
(Expr
)
734 (Is_Entity_Name
(Expression
(AC
))
735 and then Ekind
(Entity
(Expression
(AC
))) = E_Constant
736 and then Nkind
(Parent
(Entity
(Expression
(AC
)))) =
737 N_Object_Declaration
)
739 Expr
:= New_Copy_Tree
(Expression
(AC
));
741 Remove_Side_Effects
(Expr
);
744 if No
(Actions
(N
)) then
745 Set_Actions
(N
, New_List
);
748 Prepend_To
(Actions
(N
),
749 Make_Raise_Program_Error
(Loc
,
756 (RTE
(RE_Integer_Address
), Expr
),
758 Make_Attribute_Reference
(Loc
,
759 Prefix
=> New_Occurrence_Of
(E
, Loc
),
760 Attribute_Name
=> Name_Alignment
)),
761 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
762 Reason
=> PE_Misaligned_Address_Value
));
764 Warning_Msg
:= No_Error_Msg
;
765 Analyze
(First
(Actions
(N
)), Suppress
=> All_Checks
);
767 -- If the above raise action generated a warning message (for example
768 -- from Warn_On_Non_Local_Exception mode with the active restriction
769 -- No_Exception_Propagation).
771 if Warning_Msg
/= No_Error_Msg
then
773 -- If the expression has a known at compile time value, then
774 -- once we know the alignment of the type, we can check if the
775 -- exception will be raised or not, and if not, we don't need
776 -- the warning so we will kill the warning later on.
778 if Compile_Time_Known_Value
(Expr
) then
779 Alignment_Warnings
.Append
780 ((E
=> E
, A
=> Expr_Value
(Expr
), W
=> Warning_Msg
));
782 -- Add explanation of the warning generated by the check
786 ("\address value may be incompatible with alignment of "
796 -- If we have some missing run time component in configurable run time
797 -- mode then just skip the check (it is not required in any case).
799 when RE_Not_Available
=>
801 end Apply_Address_Clause_Check
;
803 -------------------------------------
804 -- Apply_Arithmetic_Overflow_Check --
805 -------------------------------------
807 procedure Apply_Arithmetic_Overflow_Check
(N
: Node_Id
) is
809 -- Use old routine in almost all cases (the only case we are treating
810 -- specially is the case of a signed integer arithmetic op with the
811 -- overflow checking mode set to MINIMIZED or ELIMINATED).
813 if Overflow_Check_Mode
= Strict
814 or else not Is_Signed_Integer_Arithmetic_Op
(N
)
816 Apply_Arithmetic_Overflow_Strict
(N
);
818 -- Otherwise use the new routine for the case of a signed integer
819 -- arithmetic op, with Do_Overflow_Check set to True, and the checking
820 -- mode is MINIMIZED or ELIMINATED.
823 Apply_Arithmetic_Overflow_Minimized_Eliminated
(N
);
825 end Apply_Arithmetic_Overflow_Check
;
827 --------------------------------------
828 -- Apply_Arithmetic_Overflow_Strict --
829 --------------------------------------
831 -- This routine is called only if the type is an integer type and an
832 -- arithmetic overflow check may be needed for op (add, subtract, or
833 -- multiply). This check is performed if Backend_Overflow_Checks_On_Target
834 -- is not enabled and Do_Overflow_Check is set. In this case we expand the
835 -- operation into a more complex sequence of tests that ensures that
836 -- overflow is properly caught.
838 -- This is used in CHECKED modes. It is identical to the code for this
839 -- cases before the big overflow earthquake, thus ensuring that in this
840 -- modes we have compatible behavior (and reliability) to what was there
841 -- before. It is also called for types other than signed integers, and if
842 -- the Do_Overflow_Check flag is off.
844 -- Note: we also call this routine if we decide in the MINIMIZED case
845 -- to give up and just generate an overflow check without any fuss.
847 procedure Apply_Arithmetic_Overflow_Strict
(N
: Node_Id
) is
848 Loc
: constant Source_Ptr
:= Sloc
(N
);
849 Typ
: constant Entity_Id
:= Etype
(N
);
850 Rtyp
: constant Entity_Id
:= Root_Type
(Typ
);
853 -- Nothing to do if Do_Overflow_Check not set or overflow checks
856 if not Do_Overflow_Check
(N
) then
860 -- An interesting special case. If the arithmetic operation appears as
861 -- the operand of a type conversion:
865 -- and all the following conditions apply:
867 -- arithmetic operation is for a signed integer type
868 -- target type type1 is a static integer subtype
869 -- range of x and y are both included in the range of type1
870 -- range of x op y is included in the range of type1
871 -- size of type1 is at least twice the result size of op
873 -- then we don't do an overflow check in any case. Instead, we transform
874 -- the operation so that we end up with:
876 -- type1 (type1 (x) op type1 (y))
878 -- This avoids intermediate overflow before the conversion. It is
879 -- explicitly permitted by RM 3.5.4(24):
881 -- For the execution of a predefined operation of a signed integer
882 -- type, the implementation need not raise Constraint_Error if the
883 -- result is outside the base range of the type, so long as the
884 -- correct result is produced.
886 -- It's hard to imagine that any programmer counts on the exception
887 -- being raised in this case, and in any case it's wrong coding to
888 -- have this expectation, given the RM permission. Furthermore, other
889 -- Ada compilers do allow such out of range results.
891 -- Note that we do this transformation even if overflow checking is
892 -- off, since this is precisely about giving the "right" result and
893 -- avoiding the need for an overflow check.
895 -- Note: this circuit is partially redundant with respect to the similar
896 -- processing in Exp_Ch4.Expand_N_Type_Conversion, but the latter deals
897 -- with cases that do not come through here. We still need the following
898 -- processing even with the Exp_Ch4 code in place, since we want to be
899 -- sure not to generate the arithmetic overflow check in these cases
900 -- (Exp_Ch4 would have a hard time removing them once generated).
902 if Is_Signed_Integer_Type
(Typ
)
903 and then Nkind
(Parent
(N
)) = N_Type_Conversion
905 Conversion_Optimization
: declare
906 Target_Type
: constant Entity_Id
:=
907 Base_Type
(Entity
(Subtype_Mark
(Parent
(N
))));
921 if Is_Integer_Type
(Target_Type
)
922 and then RM_Size
(Root_Type
(Target_Type
)) >= 2 * RM_Size
(Rtyp
)
924 Tlo
:= Expr_Value
(Type_Low_Bound
(Target_Type
));
925 Thi
:= Expr_Value
(Type_High_Bound
(Target_Type
));
928 (Left_Opnd
(N
), LOK
, Llo
, Lhi
, Assume_Valid
=> True);
930 (Right_Opnd
(N
), ROK
, Rlo
, Rhi
, Assume_Valid
=> True);
933 and then Tlo
<= Llo
and then Lhi
<= Thi
934 and then Tlo
<= Rlo
and then Rhi
<= Thi
936 Determine_Range
(N
, VOK
, Vlo
, Vhi
, Assume_Valid
=> True);
938 if VOK
and then Tlo
<= Vlo
and then Vhi
<= Thi
then
939 Rewrite
(Left_Opnd
(N
),
940 Make_Type_Conversion
(Loc
,
941 Subtype_Mark
=> New_Occurrence_Of
(Target_Type
, Loc
),
942 Expression
=> Relocate_Node
(Left_Opnd
(N
))));
944 Rewrite
(Right_Opnd
(N
),
945 Make_Type_Conversion
(Loc
,
946 Subtype_Mark
=> New_Occurrence_Of
(Target_Type
, Loc
),
947 Expression
=> Relocate_Node
(Right_Opnd
(N
))));
949 -- Rewrite the conversion operand so that the original
950 -- node is retained, in order to avoid the warning for
951 -- redundant conversions in Resolve_Type_Conversion.
953 Rewrite
(N
, Relocate_Node
(N
));
955 Set_Etype
(N
, Target_Type
);
957 Analyze_And_Resolve
(Left_Opnd
(N
), Target_Type
);
958 Analyze_And_Resolve
(Right_Opnd
(N
), Target_Type
);
960 -- Given that the target type is twice the size of the
961 -- source type, overflow is now impossible, so we can
962 -- safely kill the overflow check and return.
964 Set_Do_Overflow_Check
(N
, False);
969 end Conversion_Optimization
;
972 -- Now see if an overflow check is required
975 Siz
: constant Int
:= UI_To_Int
(Esize
(Rtyp
));
976 Dsiz
: constant Int
:= Siz
* 2;
983 -- Skip check if back end does overflow checks, or the overflow flag
984 -- is not set anyway, or we are not doing code expansion, or the
985 -- parent node is a type conversion whose operand is an arithmetic
986 -- operation on signed integers on which the expander can promote
987 -- later the operands to type Integer (see Expand_N_Type_Conversion).
989 if Backend_Overflow_Checks_On_Target
990 or else not Do_Overflow_Check
(N
)
991 or else not Expander_Active
992 or else (Present
(Parent
(N
))
993 and then Nkind
(Parent
(N
)) = N_Type_Conversion
994 and then Integer_Promotion_Possible
(Parent
(N
)))
999 -- Otherwise, generate the full general code for front end overflow
1000 -- detection, which works by doing arithmetic in a larger type:
1006 -- Typ (Checktyp (x) op Checktyp (y));
1008 -- where Typ is the type of the original expression, and Checktyp is
1009 -- an integer type of sufficient length to hold the largest possible
1012 -- If the size of check type exceeds the size of Long_Long_Integer,
1013 -- we use a different approach, expanding to:
1015 -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y)))
1017 -- where xxx is Add, Multiply or Subtract as appropriate
1019 -- Find check type if one exists
1021 if Dsiz
<= Standard_Integer_Size
then
1022 Ctyp
:= Standard_Integer
;
1024 elsif Dsiz
<= Standard_Long_Long_Integer_Size
then
1025 Ctyp
:= Standard_Long_Long_Integer
;
1027 -- No check type exists, use runtime call
1030 if Nkind
(N
) = N_Op_Add
then
1031 Cent
:= RE_Add_With_Ovflo_Check
;
1033 elsif Nkind
(N
) = N_Op_Multiply
then
1034 Cent
:= RE_Multiply_With_Ovflo_Check
;
1037 pragma Assert
(Nkind
(N
) = N_Op_Subtract
);
1038 Cent
:= RE_Subtract_With_Ovflo_Check
;
1043 Make_Function_Call
(Loc
,
1044 Name
=> New_Occurrence_Of
(RTE
(Cent
), Loc
),
1045 Parameter_Associations
=> New_List
(
1046 OK_Convert_To
(RTE
(RE_Integer_64
), Left_Opnd
(N
)),
1047 OK_Convert_To
(RTE
(RE_Integer_64
), Right_Opnd
(N
))))));
1049 Analyze_And_Resolve
(N
, Typ
);
1053 -- If we fall through, we have the case where we do the arithmetic
1054 -- in the next higher type and get the check by conversion. In these
1055 -- cases Ctyp is set to the type to be used as the check type.
1057 Opnod
:= Relocate_Node
(N
);
1059 Opnd
:= OK_Convert_To
(Ctyp
, Left_Opnd
(Opnod
));
1062 Set_Etype
(Opnd
, Ctyp
);
1063 Set_Analyzed
(Opnd
, True);
1064 Set_Left_Opnd
(Opnod
, Opnd
);
1066 Opnd
:= OK_Convert_To
(Ctyp
, Right_Opnd
(Opnod
));
1069 Set_Etype
(Opnd
, Ctyp
);
1070 Set_Analyzed
(Opnd
, True);
1071 Set_Right_Opnd
(Opnod
, Opnd
);
1073 -- The type of the operation changes to the base type of the check
1074 -- type, and we reset the overflow check indication, since clearly no
1075 -- overflow is possible now that we are using a double length type.
1076 -- We also set the Analyzed flag to avoid a recursive attempt to
1079 Set_Etype
(Opnod
, Base_Type
(Ctyp
));
1080 Set_Do_Overflow_Check
(Opnod
, False);
1081 Set_Analyzed
(Opnod
, True);
1083 -- Now build the outer conversion
1085 Opnd
:= OK_Convert_To
(Typ
, Opnod
);
1087 Set_Etype
(Opnd
, Typ
);
1089 -- In the discrete type case, we directly generate the range check
1090 -- for the outer operand. This range check will implement the
1091 -- required overflow check.
1093 if Is_Discrete_Type
(Typ
) then
1095 Generate_Range_Check
1096 (Expression
(N
), Typ
, CE_Overflow_Check_Failed
);
1098 -- For other types, we enable overflow checking on the conversion,
1099 -- after setting the node as analyzed to prevent recursive attempts
1100 -- to expand the conversion node.
1103 Set_Analyzed
(Opnd
, True);
1104 Enable_Overflow_Check
(Opnd
);
1109 when RE_Not_Available
=>
1112 end Apply_Arithmetic_Overflow_Strict
;
1114 ----------------------------------------------------
1115 -- Apply_Arithmetic_Overflow_Minimized_Eliminated --
1116 ----------------------------------------------------
1118 procedure Apply_Arithmetic_Overflow_Minimized_Eliminated
(Op
: Node_Id
) is
1119 pragma Assert
(Is_Signed_Integer_Arithmetic_Op
(Op
));
1121 Loc
: constant Source_Ptr
:= Sloc
(Op
);
1122 P
: constant Node_Id
:= Parent
(Op
);
1124 LLIB
: constant Entity_Id
:= Base_Type
(Standard_Long_Long_Integer
);
1125 -- Operands and results are of this type when we convert
1127 Result_Type
: constant Entity_Id
:= Etype
(Op
);
1128 -- Original result type
1130 Check_Mode
: constant Overflow_Mode_Type
:= Overflow_Check_Mode
;
1131 pragma Assert
(Check_Mode
in Minimized_Or_Eliminated
);
1134 -- Ranges of values for result
1137 -- Nothing to do if our parent is one of the following:
1139 -- Another signed integer arithmetic op
1140 -- A membership operation
1141 -- A comparison operation
1143 -- In all these cases, we will process at the higher level (and then
1144 -- this node will be processed during the downwards recursion that
1145 -- is part of the processing in Minimize_Eliminate_Overflows).
1147 if Is_Signed_Integer_Arithmetic_Op
(P
)
1148 or else Nkind
(P
) in N_Membership_Test
1149 or else Nkind
(P
) in N_Op_Compare
1151 -- This is also true for an alternative in a case expression
1153 or else Nkind
(P
) = N_Case_Expression_Alternative
1155 -- This is also true for a range operand in a membership test
1157 or else (Nkind
(P
) = N_Range
1158 and then Nkind
(Parent
(P
)) in N_Membership_Test
)
1160 -- If_Expressions and Case_Expressions are treated as arithmetic
1161 -- ops, but if they appear in an assignment or similar contexts
1162 -- there is no overflow check that starts from that parent node,
1163 -- so apply check now.
1165 if Nkind_In
(P
, N_If_Expression
, N_Case_Expression
)
1166 and then not Is_Signed_Integer_Arithmetic_Op
(Parent
(P
))
1174 -- Otherwise, we have a top level arithmetic operation node, and this
1175 -- is where we commence the special processing for MINIMIZED/ELIMINATED
1176 -- modes. This is the case where we tell the machinery not to move into
1177 -- Bignum mode at this top level (of course the top level operation
1178 -- will still be in Bignum mode if either of its operands are of type
1181 Minimize_Eliminate_Overflows
(Op
, Lo
, Hi
, Top_Level
=> True);
1183 -- That call may but does not necessarily change the result type of Op.
1184 -- It is the job of this routine to undo such changes, so that at the
1185 -- top level, we have the proper type. This "undoing" is a point at
1186 -- which a final overflow check may be applied.
1188 -- If the result type was not fiddled we are all set. We go to base
1189 -- types here because things may have been rewritten to generate the
1190 -- base type of the operand types.
1192 if Base_Type
(Etype
(Op
)) = Base_Type
(Result_Type
) then
1197 elsif Is_RTE
(Etype
(Op
), RE_Bignum
) then
1199 -- We need a sequence that looks like:
1201 -- Rnn : Result_Type;
1204 -- M : Mark_Id := SS_Mark;
1206 -- Rnn := Long_Long_Integer'Base (From_Bignum (Op));
1210 -- This block is inserted (using Insert_Actions), and then the node
1211 -- is replaced with a reference to Rnn.
1213 -- If our parent is a conversion node then there is no point in
1214 -- generating a conversion to Result_Type. Instead, we let the parent
1215 -- handle this. Note that this special case is not just about
1216 -- optimization. Consider
1220 -- X := Long_Long_Integer'Base (A * (B ** C));
1222 -- Now the product may fit in Long_Long_Integer but not in Integer.
1223 -- In MINIMIZED/ELIMINATED mode, we don't want to introduce an
1224 -- overflow exception for this intermediate value.
1227 Blk
: constant Node_Id
:= Make_Bignum_Block
(Loc
);
1228 Rnn
: constant Entity_Id
:= Make_Temporary
(Loc
, 'R', Op
);
1234 RHS
:= Convert_From_Bignum
(Op
);
1236 if Nkind
(P
) /= N_Type_Conversion
then
1237 Convert_To_And_Rewrite
(Result_Type
, RHS
);
1238 Rtype
:= Result_Type
;
1240 -- Interesting question, do we need a check on that conversion
1241 -- operation. Answer, not if we know the result is in range.
1242 -- At the moment we are not taking advantage of this. To be
1243 -- looked at later ???
1250 (First
(Statements
(Handled_Statement_Sequence
(Blk
))),
1251 Make_Assignment_Statement
(Loc
,
1252 Name
=> New_Occurrence_Of
(Rnn
, Loc
),
1253 Expression
=> RHS
));
1255 Insert_Actions
(Op
, New_List
(
1256 Make_Object_Declaration
(Loc
,
1257 Defining_Identifier
=> Rnn
,
1258 Object_Definition
=> New_Occurrence_Of
(Rtype
, Loc
)),
1261 Rewrite
(Op
, New_Occurrence_Of
(Rnn
, Loc
));
1262 Analyze_And_Resolve
(Op
);
1265 -- Here we know the result is Long_Long_Integer'Base, or that it has
1266 -- been rewritten because the parent operation is a conversion. See
1267 -- Apply_Arithmetic_Overflow_Strict.Conversion_Optimization.
1271 (Etype
(Op
) = LLIB
or else Nkind
(Parent
(Op
)) = N_Type_Conversion
);
1273 -- All we need to do here is to convert the result to the proper
1274 -- result type. As explained above for the Bignum case, we can
1275 -- omit this if our parent is a type conversion.
1277 if Nkind
(P
) /= N_Type_Conversion
then
1278 Convert_To_And_Rewrite
(Result_Type
, Op
);
1281 Analyze_And_Resolve
(Op
);
1283 end Apply_Arithmetic_Overflow_Minimized_Eliminated
;
1285 ----------------------------
1286 -- Apply_Constraint_Check --
1287 ----------------------------
1289 procedure Apply_Constraint_Check
1292 No_Sliding
: Boolean := False)
1294 Desig_Typ
: Entity_Id
;
1297 -- No checks inside a generic (check the instantiations)
1299 if Inside_A_Generic
then
1303 -- Apply required constraint checks
1305 if Is_Scalar_Type
(Typ
) then
1306 Apply_Scalar_Range_Check
(N
, Typ
);
1308 elsif Is_Array_Type
(Typ
) then
1310 -- A useful optimization: an aggregate with only an others clause
1311 -- always has the right bounds.
1313 if Nkind
(N
) = N_Aggregate
1314 and then No
(Expressions
(N
))
1316 (First
(Choices
(First
(Component_Associations
(N
)))))
1322 if Is_Constrained
(Typ
) then
1323 Apply_Length_Check
(N
, Typ
);
1326 Apply_Range_Check
(N
, Typ
);
1329 Apply_Range_Check
(N
, Typ
);
1332 elsif (Is_Record_Type
(Typ
) or else Is_Private_Type
(Typ
))
1333 and then Has_Discriminants
(Base_Type
(Typ
))
1334 and then Is_Constrained
(Typ
)
1336 Apply_Discriminant_Check
(N
, Typ
);
1338 elsif Is_Access_Type
(Typ
) then
1340 Desig_Typ
:= Designated_Type
(Typ
);
1342 -- No checks necessary if expression statically null
1344 if Known_Null
(N
) then
1345 if Can_Never_Be_Null
(Typ
) then
1346 Install_Null_Excluding_Check
(N
);
1349 -- No sliding possible on access to arrays
1351 elsif Is_Array_Type
(Desig_Typ
) then
1352 if Is_Constrained
(Desig_Typ
) then
1353 Apply_Length_Check
(N
, Typ
);
1356 Apply_Range_Check
(N
, Typ
);
1358 -- Do not install a discriminant check for a constrained subtype
1359 -- created for an unconstrained nominal type because the subtype
1360 -- has the correct constraints by construction.
1362 elsif Has_Discriminants
(Base_Type
(Desig_Typ
))
1363 and then Is_Constrained
(Desig_Typ
)
1364 and then not Is_Constr_Subt_For_U_Nominal
(Desig_Typ
)
1366 Apply_Discriminant_Check
(N
, Typ
);
1369 -- Apply the 2005 Null_Excluding check. Note that we do not apply
1370 -- this check if the constraint node is illegal, as shown by having
1371 -- an error posted. This additional guard prevents cascaded errors
1372 -- and compiler aborts on illegal programs involving Ada 2005 checks.
1374 if Can_Never_Be_Null
(Typ
)
1375 and then not Can_Never_Be_Null
(Etype
(N
))
1376 and then not Error_Posted
(N
)
1378 Install_Null_Excluding_Check
(N
);
1381 end Apply_Constraint_Check
;
1383 ------------------------------
1384 -- Apply_Discriminant_Check --
1385 ------------------------------
1387 procedure Apply_Discriminant_Check
1390 Lhs
: Node_Id
:= Empty
)
1392 Loc
: constant Source_Ptr
:= Sloc
(N
);
1393 Do_Access
: constant Boolean := Is_Access_Type
(Typ
);
1394 S_Typ
: Entity_Id
:= Etype
(N
);
1398 function Denotes_Explicit_Dereference
(Obj
: Node_Id
) return Boolean;
1399 -- A heap object with an indefinite subtype is constrained by its
1400 -- initial value, and assigning to it requires a constraint_check.
1401 -- The target may be an explicit dereference, or a renaming of one.
1403 function Is_Aliased_Unconstrained_Component
return Boolean;
1404 -- It is possible for an aliased component to have a nominal
1405 -- unconstrained subtype (through instantiation). If this is a
1406 -- discriminated component assigned in the expansion of an aggregate
1407 -- in an initialization, the check must be suppressed. This unusual
1408 -- situation requires a predicate of its own.
1410 ----------------------------------
1411 -- Denotes_Explicit_Dereference --
1412 ----------------------------------
1414 function Denotes_Explicit_Dereference
(Obj
: Node_Id
) return Boolean is
1417 Nkind
(Obj
) = N_Explicit_Dereference
1419 (Is_Entity_Name
(Obj
)
1420 and then Present
(Renamed_Object
(Entity
(Obj
)))
1421 and then Nkind
(Renamed_Object
(Entity
(Obj
))) =
1422 N_Explicit_Dereference
);
1423 end Denotes_Explicit_Dereference
;
1425 ----------------------------------------
1426 -- Is_Aliased_Unconstrained_Component --
1427 ----------------------------------------
1429 function Is_Aliased_Unconstrained_Component
return Boolean is
1434 if Nkind
(Lhs
) /= N_Selected_Component
then
1437 Comp
:= Entity
(Selector_Name
(Lhs
));
1438 Pref
:= Prefix
(Lhs
);
1441 if Ekind
(Comp
) /= E_Component
1442 or else not Is_Aliased
(Comp
)
1447 return not Comes_From_Source
(Pref
)
1448 and then In_Instance
1449 and then not Is_Constrained
(Etype
(Comp
));
1450 end Is_Aliased_Unconstrained_Component
;
1452 -- Start of processing for Apply_Discriminant_Check
1456 T_Typ
:= Designated_Type
(Typ
);
1461 -- If the expression is a function call that returns a limited object
1462 -- it cannot be copied. It is not clear how to perform the proper
1463 -- discriminant check in this case because the discriminant value must
1464 -- be retrieved from the constructed object itself.
1466 if Nkind
(N
) = N_Function_Call
1467 and then Is_Limited_Type
(Typ
)
1468 and then Is_Entity_Name
(Name
(N
))
1469 and then Returns_By_Ref
(Entity
(Name
(N
)))
1474 -- Only apply checks when generating code and discriminant checks are
1475 -- not suppressed. In GNATprove mode, we do not apply the checks, but we
1476 -- still analyze the expression to possibly issue errors on SPARK code
1477 -- when a run-time error can be detected at compile time.
1479 if not GNATprove_Mode
then
1480 if not Expander_Active
1481 or else Discriminant_Checks_Suppressed
(T_Typ
)
1487 -- No discriminant checks necessary for an access when expression is
1488 -- statically Null. This is not only an optimization, it is fundamental
1489 -- because otherwise discriminant checks may be generated in init procs
1490 -- for types containing an access to a not-yet-frozen record, causing a
1491 -- deadly forward reference.
1493 -- Also, if the expression is of an access type whose designated type is
1494 -- incomplete, then the access value must be null and we suppress the
1497 if Known_Null
(N
) then
1500 elsif Is_Access_Type
(S_Typ
) then
1501 S_Typ
:= Designated_Type
(S_Typ
);
1503 if Ekind
(S_Typ
) = E_Incomplete_Type
then
1508 -- If an assignment target is present, then we need to generate the
1509 -- actual subtype if the target is a parameter or aliased object with
1510 -- an unconstrained nominal subtype.
1512 -- Ada 2005 (AI-363): For Ada 2005, we limit the building of the actual
1513 -- subtype to the parameter and dereference cases, since other aliased
1514 -- objects are unconstrained (unless the nominal subtype is explicitly
1518 and then (Present
(Param_Entity
(Lhs
))
1519 or else (Ada_Version
< Ada_2005
1520 and then not Is_Constrained
(T_Typ
)
1521 and then Is_Aliased_View
(Lhs
)
1522 and then not Is_Aliased_Unconstrained_Component
)
1523 or else (Ada_Version
>= Ada_2005
1524 and then not Is_Constrained
(T_Typ
)
1525 and then Denotes_Explicit_Dereference
(Lhs
)
1526 and then Nkind
(Original_Node
(Lhs
)) /=
1529 T_Typ
:= Get_Actual_Subtype
(Lhs
);
1532 -- Nothing to do if the type is unconstrained (this is the case where
1533 -- the actual subtype in the RM sense of N is unconstrained and no check
1536 if not Is_Constrained
(T_Typ
) then
1539 -- Ada 2005: nothing to do if the type is one for which there is a
1540 -- partial view that is constrained.
1542 elsif Ada_Version
>= Ada_2005
1543 and then Object_Type_Has_Constrained_Partial_View
1544 (Typ
=> Base_Type
(T_Typ
),
1545 Scop
=> Current_Scope
)
1550 -- Nothing to do if the type is an Unchecked_Union
1552 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
1556 -- Suppress checks if the subtypes are the same. The check must be
1557 -- preserved in an assignment to a formal, because the constraint is
1558 -- given by the actual.
1560 if Nkind
(Original_Node
(N
)) /= N_Allocator
1562 or else not Is_Entity_Name
(Lhs
)
1563 or else No
(Param_Entity
(Lhs
)))
1566 or else (Do_Access
and then Designated_Type
(Typ
) = S_Typ
))
1567 and then not Is_Aliased_View
(Lhs
)
1572 -- We can also eliminate checks on allocators with a subtype mark that
1573 -- coincides with the context type. The context type may be a subtype
1574 -- without a constraint (common case, a generic actual).
1576 elsif Nkind
(Original_Node
(N
)) = N_Allocator
1577 and then Is_Entity_Name
(Expression
(Original_Node
(N
)))
1580 Alloc_Typ
: constant Entity_Id
:=
1581 Entity
(Expression
(Original_Node
(N
)));
1584 if Alloc_Typ
= T_Typ
1585 or else (Nkind
(Parent
(T_Typ
)) = N_Subtype_Declaration
1586 and then Is_Entity_Name
(
1587 Subtype_Indication
(Parent
(T_Typ
)))
1588 and then Alloc_Typ
= Base_Type
(T_Typ
))
1596 -- See if we have a case where the types are both constrained, and all
1597 -- the constraints are constants. In this case, we can do the check
1598 -- successfully at compile time.
1600 -- We skip this check for the case where the node is rewritten as
1601 -- an allocator, because it already carries the context subtype,
1602 -- and extracting the discriminants from the aggregate is messy.
1604 if Is_Constrained
(S_Typ
)
1605 and then Nkind
(Original_Node
(N
)) /= N_Allocator
1615 -- S_Typ may not have discriminants in the case where it is a
1616 -- private type completed by a default discriminated type. In that
1617 -- case, we need to get the constraints from the underlying type.
1618 -- If the underlying type is unconstrained (i.e. has no default
1619 -- discriminants) no check is needed.
1621 if Has_Discriminants
(S_Typ
) then
1622 Discr
:= First_Discriminant
(S_Typ
);
1623 DconS
:= First_Elmt
(Discriminant_Constraint
(S_Typ
));
1626 Discr
:= First_Discriminant
(Underlying_Type
(S_Typ
));
1629 (Discriminant_Constraint
(Underlying_Type
(S_Typ
)));
1635 -- A further optimization: if T_Typ is derived from S_Typ
1636 -- without imposing a constraint, no check is needed.
1638 if Nkind
(Original_Node
(Parent
(T_Typ
))) =
1639 N_Full_Type_Declaration
1642 Type_Def
: constant Node_Id
:=
1643 Type_Definition
(Original_Node
(Parent
(T_Typ
)));
1645 if Nkind
(Type_Def
) = N_Derived_Type_Definition
1646 and then Is_Entity_Name
(Subtype_Indication
(Type_Def
))
1647 and then Entity
(Subtype_Indication
(Type_Def
)) = S_Typ
1655 -- Constraint may appear in full view of type
1657 if Ekind
(T_Typ
) = E_Private_Subtype
1658 and then Present
(Full_View
(T_Typ
))
1661 First_Elmt
(Discriminant_Constraint
(Full_View
(T_Typ
)));
1664 First_Elmt
(Discriminant_Constraint
(T_Typ
));
1667 while Present
(Discr
) loop
1668 ItemS
:= Node
(DconS
);
1669 ItemT
:= Node
(DconT
);
1671 -- For a discriminated component type constrained by the
1672 -- current instance of an enclosing type, there is no
1673 -- applicable discriminant check.
1675 if Nkind
(ItemT
) = N_Attribute_Reference
1676 and then Is_Access_Type
(Etype
(ItemT
))
1677 and then Is_Entity_Name
(Prefix
(ItemT
))
1678 and then Is_Type
(Entity
(Prefix
(ItemT
)))
1683 -- If the expressions for the discriminants are identical
1684 -- and it is side-effect free (for now just an entity),
1685 -- this may be a shared constraint, e.g. from a subtype
1686 -- without a constraint introduced as a generic actual.
1687 -- Examine other discriminants if any.
1690 and then Is_Entity_Name
(ItemS
)
1694 elsif not Is_OK_Static_Expression
(ItemS
)
1695 or else not Is_OK_Static_Expression
(ItemT
)
1699 elsif Expr_Value
(ItemS
) /= Expr_Value
(ItemT
) then
1700 if Do_Access
then -- needs run-time check.
1703 Apply_Compile_Time_Constraint_Error
1704 (N
, "incorrect value for discriminant&??",
1705 CE_Discriminant_Check_Failed
, Ent
=> Discr
);
1712 Next_Discriminant
(Discr
);
1721 -- In GNATprove mode, we do not apply the checks
1723 if GNATprove_Mode
then
1727 -- Here we need a discriminant check. First build the expression
1728 -- for the comparisons of the discriminants:
1730 -- (n.disc1 /= typ.disc1) or else
1731 -- (n.disc2 /= typ.disc2) or else
1733 -- (n.discn /= typ.discn)
1735 Cond
:= Build_Discriminant_Checks
(N
, T_Typ
);
1737 -- If Lhs is set and is a parameter, then the condition is guarded by:
1738 -- lhs'constrained and then (condition built above)
1740 if Present
(Param_Entity
(Lhs
)) then
1744 Make_Attribute_Reference
(Loc
,
1745 Prefix
=> New_Occurrence_Of
(Param_Entity
(Lhs
), Loc
),
1746 Attribute_Name
=> Name_Constrained
),
1747 Right_Opnd
=> Cond
);
1751 Cond
:= Guard_Access
(Cond
, Loc
, N
);
1755 Make_Raise_Constraint_Error
(Loc
,
1757 Reason
=> CE_Discriminant_Check_Failed
));
1758 end Apply_Discriminant_Check
;
1760 -------------------------
1761 -- Apply_Divide_Checks --
1762 -------------------------
1764 procedure Apply_Divide_Checks
(N
: Node_Id
) is
1765 Loc
: constant Source_Ptr
:= Sloc
(N
);
1766 Typ
: constant Entity_Id
:= Etype
(N
);
1767 Left
: constant Node_Id
:= Left_Opnd
(N
);
1768 Right
: constant Node_Id
:= Right_Opnd
(N
);
1770 Mode
: constant Overflow_Mode_Type
:= Overflow_Check_Mode
;
1771 -- Current overflow checking mode
1781 pragma Warnings
(Off
, Lhi
);
1782 -- Don't actually use this value
1785 -- If we are operating in MINIMIZED or ELIMINATED mode, and we are
1786 -- operating on signed integer types, then the only thing this routine
1787 -- does is to call Apply_Arithmetic_Overflow_Minimized_Eliminated. That
1788 -- procedure will (possibly later on during recursive downward calls),
1789 -- ensure that any needed overflow/division checks are properly applied.
1791 if Mode
in Minimized_Or_Eliminated
1792 and then Is_Signed_Integer_Type
(Typ
)
1794 Apply_Arithmetic_Overflow_Minimized_Eliminated
(N
);
1798 -- Proceed here in SUPPRESSED or CHECKED modes
1801 and then not Backend_Divide_Checks_On_Target
1802 and then Check_Needed
(Right
, Division_Check
)
1804 Determine_Range
(Right
, ROK
, Rlo
, Rhi
, Assume_Valid
=> True);
1806 -- Deal with division check
1808 if Do_Division_Check
(N
)
1809 and then not Division_Checks_Suppressed
(Typ
)
1811 Apply_Division_Check
(N
, Rlo
, Rhi
, ROK
);
1814 -- Deal with overflow check
1816 if Do_Overflow_Check
(N
)
1817 and then not Overflow_Checks_Suppressed
(Etype
(N
))
1819 Set_Do_Overflow_Check
(N
, False);
1821 -- Test for extremely annoying case of xxx'First divided by -1
1822 -- for division of signed integer types (only overflow case).
1824 if Nkind
(N
) = N_Op_Divide
1825 and then Is_Signed_Integer_Type
(Typ
)
1827 Determine_Range
(Left
, LOK
, Llo
, Lhi
, Assume_Valid
=> True);
1828 LLB
:= Expr_Value
(Type_Low_Bound
(Base_Type
(Typ
)));
1830 if ((not ROK
) or else (Rlo
<= (-1) and then (-1) <= Rhi
))
1832 ((not LOK
) or else (Llo
= LLB
))
1834 -- Ensure that expressions are not evaluated twice (once
1835 -- for their runtime checks and once for their regular
1838 Force_Evaluation
(Left
, Mode
=> Strict
);
1839 Force_Evaluation
(Right
, Mode
=> Strict
);
1842 Make_Raise_Constraint_Error
(Loc
,
1848 Duplicate_Subexpr_Move_Checks
(Left
),
1849 Right_Opnd
=> Make_Integer_Literal
(Loc
, LLB
)),
1853 Left_Opnd
=> Duplicate_Subexpr
(Right
),
1854 Right_Opnd
=> Make_Integer_Literal
(Loc
, -1))),
1856 Reason
=> CE_Overflow_Check_Failed
));
1861 end Apply_Divide_Checks
;
1863 --------------------------
1864 -- Apply_Division_Check --
1865 --------------------------
1867 procedure Apply_Division_Check
1873 pragma Assert
(Do_Division_Check
(N
));
1875 Loc
: constant Source_Ptr
:= Sloc
(N
);
1876 Right
: constant Node_Id
:= Right_Opnd
(N
);
1880 and then not Backend_Divide_Checks_On_Target
1881 and then Check_Needed
(Right
, Division_Check
)
1883 -- See if division by zero possible, and if so generate test. This
1884 -- part of the test is not controlled by the -gnato switch, since
1885 -- it is a Division_Check and not an Overflow_Check.
1887 if Do_Division_Check
(N
) then
1888 Set_Do_Division_Check
(N
, False);
1890 if (not ROK
) or else (Rlo
<= 0 and then 0 <= Rhi
) then
1892 Make_Raise_Constraint_Error
(Loc
,
1895 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(Right
),
1896 Right_Opnd
=> Make_Integer_Literal
(Loc
, 0)),
1897 Reason
=> CE_Divide_By_Zero
));
1901 end Apply_Division_Check
;
1903 ----------------------------------
1904 -- Apply_Float_Conversion_Check --
1905 ----------------------------------
1907 -- Let F and I be the source and target types of the conversion. The RM
1908 -- specifies that a floating-point value X is rounded to the nearest
1909 -- integer, with halfway cases being rounded away from zero. The rounded
1910 -- value of X is checked against I'Range.
1912 -- The catch in the above paragraph is that there is no good way to know
1913 -- whether the round-to-integer operation resulted in overflow. A remedy is
1914 -- to perform a range check in the floating-point domain instead, however:
1916 -- (1) The bounds may not be known at compile time
1917 -- (2) The check must take into account rounding or truncation.
1918 -- (3) The range of type I may not be exactly representable in F.
1919 -- (4) For the rounding case, The end-points I'First - 0.5 and
1920 -- I'Last + 0.5 may or may not be in range, depending on the
1921 -- sign of I'First and I'Last.
1922 -- (5) X may be a NaN, which will fail any comparison
1924 -- The following steps correctly convert X with rounding:
1926 -- (1) If either I'First or I'Last is not known at compile time, use
1927 -- I'Base instead of I in the next three steps and perform a
1928 -- regular range check against I'Range after conversion.
1929 -- (2) If I'First - 0.5 is representable in F then let Lo be that
1930 -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be
1931 -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First).
1932 -- In other words, take one of the closest floating-point numbers
1933 -- (which is an integer value) to I'First, and see if it is in
1935 -- (3) If I'Last + 0.5 is representable in F then let Hi be that value
1936 -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be
1937 -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last).
1938 -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo)
1939 -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi)
1941 -- For the truncating case, replace steps (2) and (3) as follows:
1942 -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK
1943 -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let
1945 -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK
1946 -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let
1949 procedure Apply_Float_Conversion_Check
1951 Target_Typ
: Entity_Id
)
1953 LB
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1954 HB
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1955 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1956 Expr_Type
: constant Entity_Id
:= Base_Type
(Etype
(Ck_Node
));
1957 Target_Base
: constant Entity_Id
:=
1958 Implementation_Base_Type
(Target_Typ
);
1960 Par
: constant Node_Id
:= Parent
(Ck_Node
);
1961 pragma Assert
(Nkind
(Par
) = N_Type_Conversion
);
1962 -- Parent of check node, must be a type conversion
1964 Truncate
: constant Boolean := Float_Truncate
(Par
);
1965 Max_Bound
: constant Uint
:=
1967 (Machine_Radix_Value
(Expr_Type
),
1968 Machine_Mantissa_Value
(Expr_Type
) - 1) - 1;
1970 -- Largest bound, so bound plus or minus half is a machine number of F
1972 Ifirst
, Ilast
: Uint
;
1973 -- Bounds of integer type
1976 -- Bounds to check in floating-point domain
1978 Lo_OK
, Hi_OK
: Boolean;
1979 -- True iff Lo resp. Hi belongs to I'Range
1981 Lo_Chk
, Hi_Chk
: Node_Id
;
1982 -- Expressions that are False iff check fails
1984 Reason
: RT_Exception_Code
;
1987 -- We do not need checks if we are not generating code (i.e. the full
1988 -- expander is not active). In SPARK mode, we specifically don't want
1989 -- the frontend to expand these checks, which are dealt with directly
1990 -- in the formal verification backend.
1992 if not Expander_Active
then
1996 if not Compile_Time_Known_Value
(LB
)
1997 or not Compile_Time_Known_Value
(HB
)
2000 -- First check that the value falls in the range of the base type,
2001 -- to prevent overflow during conversion and then perform a
2002 -- regular range check against the (dynamic) bounds.
2004 pragma Assert
(Target_Base
/= Target_Typ
);
2006 Temp
: constant Entity_Id
:= Make_Temporary
(Loc
, 'T', Par
);
2009 Apply_Float_Conversion_Check
(Ck_Node
, Target_Base
);
2010 Set_Etype
(Temp
, Target_Base
);
2012 Insert_Action
(Parent
(Par
),
2013 Make_Object_Declaration
(Loc
,
2014 Defining_Identifier
=> Temp
,
2015 Object_Definition
=> New_Occurrence_Of
(Target_Typ
, Loc
),
2016 Expression
=> New_Copy_Tree
(Par
)),
2017 Suppress
=> All_Checks
);
2020 Make_Raise_Constraint_Error
(Loc
,
2023 Left_Opnd
=> New_Occurrence_Of
(Temp
, Loc
),
2024 Right_Opnd
=> New_Occurrence_Of
(Target_Typ
, Loc
)),
2025 Reason
=> CE_Range_Check_Failed
));
2026 Rewrite
(Par
, New_Occurrence_Of
(Temp
, Loc
));
2032 -- Get the (static) bounds of the target type
2034 Ifirst
:= Expr_Value
(LB
);
2035 Ilast
:= Expr_Value
(HB
);
2037 -- A simple optimization: if the expression is a universal literal,
2038 -- we can do the comparison with the bounds and the conversion to
2039 -- an integer type statically. The range checks are unchanged.
2041 if Nkind
(Ck_Node
) = N_Real_Literal
2042 and then Etype
(Ck_Node
) = Universal_Real
2043 and then Is_Integer_Type
(Target_Typ
)
2044 and then Nkind
(Parent
(Ck_Node
)) = N_Type_Conversion
2047 Int_Val
: constant Uint
:= UR_To_Uint
(Realval
(Ck_Node
));
2050 if Int_Val
<= Ilast
and then Int_Val
>= Ifirst
then
2052 -- Conversion is safe
2054 Rewrite
(Parent
(Ck_Node
),
2055 Make_Integer_Literal
(Loc
, UI_To_Int
(Int_Val
)));
2056 Analyze_And_Resolve
(Parent
(Ck_Node
), Target_Typ
);
2062 -- Check against lower bound
2064 if Truncate
and then Ifirst
> 0 then
2065 Lo
:= Pred
(Expr_Type
, UR_From_Uint
(Ifirst
));
2069 Lo
:= Succ
(Expr_Type
, UR_From_Uint
(Ifirst
- 1));
2072 elsif abs (Ifirst
) < Max_Bound
then
2073 Lo
:= UR_From_Uint
(Ifirst
) - Ureal_Half
;
2074 Lo_OK
:= (Ifirst
> 0);
2077 Lo
:= Machine
(Expr_Type
, UR_From_Uint
(Ifirst
), Round_Even
, Ck_Node
);
2078 Lo_OK
:= (Lo
>= UR_From_Uint
(Ifirst
));
2083 -- Lo_Chk := (X >= Lo)
2085 Lo_Chk
:= Make_Op_Ge
(Loc
,
2086 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
2087 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
2090 -- Lo_Chk := (X > Lo)
2092 Lo_Chk
:= Make_Op_Gt
(Loc
,
2093 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
2094 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
2097 -- Check against higher bound
2099 if Truncate
and then Ilast
< 0 then
2100 Hi
:= Succ
(Expr_Type
, UR_From_Uint
(Ilast
));
2104 Hi
:= Pred
(Expr_Type
, UR_From_Uint
(Ilast
+ 1));
2107 elsif abs (Ilast
) < Max_Bound
then
2108 Hi
:= UR_From_Uint
(Ilast
) + Ureal_Half
;
2109 Hi_OK
:= (Ilast
< 0);
2111 Hi
:= Machine
(Expr_Type
, UR_From_Uint
(Ilast
), Round_Even
, Ck_Node
);
2112 Hi_OK
:= (Hi
<= UR_From_Uint
(Ilast
));
2117 -- Hi_Chk := (X <= Hi)
2119 Hi_Chk
:= Make_Op_Le
(Loc
,
2120 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
2121 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
2124 -- Hi_Chk := (X < Hi)
2126 Hi_Chk
:= Make_Op_Lt
(Loc
,
2127 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
2128 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
2131 -- If the bounds of the target type are the same as those of the base
2132 -- type, the check is an overflow check as a range check is not
2133 -- performed in these cases.
2135 if Expr_Value
(Type_Low_Bound
(Target_Base
)) = Ifirst
2136 and then Expr_Value
(Type_High_Bound
(Target_Base
)) = Ilast
2138 Reason
:= CE_Overflow_Check_Failed
;
2140 Reason
:= CE_Range_Check_Failed
;
2143 -- Raise CE if either conditions does not hold
2145 Insert_Action
(Ck_Node
,
2146 Make_Raise_Constraint_Error
(Loc
,
2147 Condition
=> Make_Op_Not
(Loc
, Make_And_Then
(Loc
, Lo_Chk
, Hi_Chk
)),
2149 end Apply_Float_Conversion_Check
;
2151 ------------------------
2152 -- Apply_Length_Check --
2153 ------------------------
2155 procedure Apply_Length_Check
2157 Target_Typ
: Entity_Id
;
2158 Source_Typ
: Entity_Id
:= Empty
)
2161 Apply_Selected_Length_Checks
2162 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
2163 end Apply_Length_Check
;
2165 -------------------------------------
2166 -- Apply_Parameter_Aliasing_Checks --
2167 -------------------------------------
2169 procedure Apply_Parameter_Aliasing_Checks
2173 Loc
: constant Source_Ptr
:= Sloc
(Call
);
2175 function May_Cause_Aliasing
2176 (Formal_1
: Entity_Id
;
2177 Formal_2
: Entity_Id
) return Boolean;
2178 -- Determine whether two formal parameters can alias each other
2179 -- depending on their modes.
2181 function Original_Actual
(N
: Node_Id
) return Node_Id
;
2182 -- The expander may replace an actual with a temporary for the sake of
2183 -- side effect removal. The temporary may hide a potential aliasing as
2184 -- it does not share the address of the actual. This routine attempts
2185 -- to retrieve the original actual.
2187 procedure Overlap_Check
2188 (Actual_1
: Node_Id
;
2190 Formal_1
: Entity_Id
;
2191 Formal_2
: Entity_Id
;
2192 Check
: in out Node_Id
);
2193 -- Create a check to determine whether Actual_1 overlaps with Actual_2.
2194 -- If detailed exception messages are enabled, the check is augmented to
2195 -- provide information about the names of the corresponding formals. See
2196 -- the body for details. Actual_1 and Actual_2 denote the two actuals to
2197 -- be tested. Formal_1 and Formal_2 denote the corresponding formals.
2198 -- Check contains all and-ed simple tests generated so far or remains
2199 -- unchanged in the case of detailed exception messaged.
2201 ------------------------
2202 -- May_Cause_Aliasing --
2203 ------------------------
2205 function May_Cause_Aliasing
2206 (Formal_1
: Entity_Id
;
2207 Formal_2
: Entity_Id
) return Boolean
2210 -- The following combination cannot lead to aliasing
2212 -- Formal 1 Formal 2
2215 if Ekind
(Formal_1
) = E_In_Parameter
2217 Ekind
(Formal_2
) = E_In_Parameter
2221 -- The following combinations may lead to aliasing
2223 -- Formal 1 Formal 2
2233 end May_Cause_Aliasing
;
2235 ---------------------
2236 -- Original_Actual --
2237 ---------------------
2239 function Original_Actual
(N
: Node_Id
) return Node_Id
is
2241 if Nkind
(N
) = N_Type_Conversion
then
2242 return Expression
(N
);
2244 -- The expander created a temporary to capture the result of a type
2245 -- conversion where the expression is the real actual.
2247 elsif Nkind
(N
) = N_Identifier
2248 and then Present
(Original_Node
(N
))
2249 and then Nkind
(Original_Node
(N
)) = N_Type_Conversion
2251 return Expression
(Original_Node
(N
));
2255 end Original_Actual
;
2261 procedure Overlap_Check
2262 (Actual_1
: Node_Id
;
2264 Formal_1
: Entity_Id
;
2265 Formal_2
: Entity_Id
;
2266 Check
: in out Node_Id
)
2269 ID_Casing
: constant Casing_Type
:=
2270 Identifier_Casing
(Source_Index
(Current_Sem_Unit
));
2274 -- Actual_1'Overlaps_Storage (Actual_2)
2277 Make_Attribute_Reference
(Loc
,
2278 Prefix
=> New_Copy_Tree
(Original_Actual
(Actual_1
)),
2279 Attribute_Name
=> Name_Overlaps_Storage
,
2281 New_List
(New_Copy_Tree
(Original_Actual
(Actual_2
))));
2283 -- Generate the following check when detailed exception messages are
2286 -- if Actual_1'Overlaps_Storage (Actual_2) then
2287 -- raise Program_Error with <detailed message>;
2290 if Exception_Extra_Info
then
2293 -- Do not generate location information for internal calls
2295 if Comes_From_Source
(Call
) then
2296 Store_String_Chars
(Build_Location_String
(Loc
));
2297 Store_String_Char
(' ');
2300 Store_String_Chars
("aliased parameters, actuals for """);
2302 Get_Name_String
(Chars
(Formal_1
));
2303 Set_Casing
(ID_Casing
);
2304 Store_String_Chars
(Name_Buffer
(1 .. Name_Len
));
2306 Store_String_Chars
(""" and """);
2308 Get_Name_String
(Chars
(Formal_2
));
2309 Set_Casing
(ID_Casing
);
2310 Store_String_Chars
(Name_Buffer
(1 .. Name_Len
));
2312 Store_String_Chars
(""" overlap");
2314 Insert_Action
(Call
,
2315 Make_If_Statement
(Loc
,
2317 Then_Statements
=> New_List
(
2318 Make_Raise_Statement
(Loc
,
2320 New_Occurrence_Of
(Standard_Program_Error
, Loc
),
2321 Expression
=> Make_String_Literal
(Loc
, End_String
)))));
2323 -- Create a sequence of overlapping checks by and-ing them all
2333 Right_Opnd
=> Cond
);
2343 Formal_1
: Entity_Id
;
2344 Formal_2
: Entity_Id
;
2345 Orig_Act_1
: Node_Id
;
2346 Orig_Act_2
: Node_Id
;
2348 -- Start of processing for Apply_Parameter_Aliasing_Checks
2353 Actual_1
:= First_Actual
(Call
);
2354 Formal_1
:= First_Formal
(Subp
);
2355 while Present
(Actual_1
) and then Present
(Formal_1
) loop
2356 Orig_Act_1
:= Original_Actual
(Actual_1
);
2358 -- Ensure that the actual is an object that is not passed by value.
2359 -- Elementary types are always passed by value, therefore actuals of
2360 -- such types cannot lead to aliasing. An aggregate is an object in
2361 -- Ada 2012, but an actual that is an aggregate cannot overlap with
2362 -- another actual. A type that is By_Reference (such as an array of
2363 -- controlled types) is not subject to the check because any update
2364 -- will be done in place and a subsequent read will always see the
2365 -- correct value, see RM 6.2 (12/3).
2367 if Nkind
(Orig_Act_1
) = N_Aggregate
2368 or else (Nkind
(Orig_Act_1
) = N_Qualified_Expression
2369 and then Nkind
(Expression
(Orig_Act_1
)) = N_Aggregate
)
2373 elsif Is_Object_Reference
(Orig_Act_1
)
2374 and then not Is_Elementary_Type
(Etype
(Orig_Act_1
))
2375 and then not Is_By_Reference_Type
(Etype
(Orig_Act_1
))
2377 Actual_2
:= Next_Actual
(Actual_1
);
2378 Formal_2
:= Next_Formal
(Formal_1
);
2379 while Present
(Actual_2
) and then Present
(Formal_2
) loop
2380 Orig_Act_2
:= Original_Actual
(Actual_2
);
2382 -- The other actual we are testing against must also denote
2383 -- a non pass-by-value object. Generate the check only when
2384 -- the mode of the two formals may lead to aliasing.
2386 if Is_Object_Reference
(Orig_Act_2
)
2387 and then not Is_Elementary_Type
(Etype
(Orig_Act_2
))
2388 and then May_Cause_Aliasing
(Formal_1
, Formal_2
)
2390 Remove_Side_Effects
(Actual_1
);
2391 Remove_Side_Effects
(Actual_2
);
2394 (Actual_1
=> Actual_1
,
2395 Actual_2
=> Actual_2
,
2396 Formal_1
=> Formal_1
,
2397 Formal_2
=> Formal_2
,
2401 Next_Actual
(Actual_2
);
2402 Next_Formal
(Formal_2
);
2406 Next_Actual
(Actual_1
);
2407 Next_Formal
(Formal_1
);
2410 -- Place a simple check right before the call
2412 if Present
(Check
) and then not Exception_Extra_Info
then
2413 Insert_Action
(Call
,
2414 Make_Raise_Program_Error
(Loc
,
2416 Reason
=> PE_Aliased_Parameters
));
2418 end Apply_Parameter_Aliasing_Checks
;
2420 -------------------------------------
2421 -- Apply_Parameter_Validity_Checks --
2422 -------------------------------------
2424 procedure Apply_Parameter_Validity_Checks
(Subp
: Entity_Id
) is
2425 Subp_Decl
: Node_Id
;
2427 procedure Add_Validity_Check
2428 (Formal
: Entity_Id
;
2430 For_Result
: Boolean := False);
2431 -- Add a single 'Valid[_Scalar] check which verifies the initialization
2432 -- of Formal. Prag_Nam denotes the pre or post condition pragma name.
2433 -- Set flag For_Result when to verify the result of a function.
2435 ------------------------
2436 -- Add_Validity_Check --
2437 ------------------------
2439 procedure Add_Validity_Check
2440 (Formal
: Entity_Id
;
2442 For_Result
: Boolean := False)
2444 procedure Build_Pre_Post_Condition
(Expr
: Node_Id
);
2445 -- Create a pre/postcondition pragma that tests expression Expr
2447 ------------------------------
2448 -- Build_Pre_Post_Condition --
2449 ------------------------------
2451 procedure Build_Pre_Post_Condition
(Expr
: Node_Id
) is
2452 Loc
: constant Source_Ptr
:= Sloc
(Subp
);
2460 Pragma_Argument_Associations
=> New_List
(
2461 Make_Pragma_Argument_Association
(Loc
,
2462 Chars
=> Name_Check
,
2463 Expression
=> Expr
)));
2465 -- Add a message unless exception messages are suppressed
2467 if not Exception_Locations_Suppressed
then
2468 Append_To
(Pragma_Argument_Associations
(Prag
),
2469 Make_Pragma_Argument_Association
(Loc
,
2470 Chars
=> Name_Message
,
2472 Make_String_Literal
(Loc
,
2474 & Get_Name_String
(Prag_Nam
)
2476 & Build_Location_String
(Loc
))));
2479 -- Insert the pragma in the tree
2481 if Nkind
(Parent
(Subp_Decl
)) = N_Compilation_Unit
then
2482 Add_Global_Declaration
(Prag
);
2485 -- PPC pragmas associated with subprogram bodies must be inserted
2486 -- in the declarative part of the body.
2488 elsif Nkind
(Subp_Decl
) = N_Subprogram_Body
then
2489 Decls
:= Declarations
(Subp_Decl
);
2493 Set_Declarations
(Subp_Decl
, Decls
);
2496 Prepend_To
(Decls
, Prag
);
2499 -- For subprogram declarations insert the PPC pragma right after
2500 -- the declarative node.
2503 Insert_After_And_Analyze
(Subp_Decl
, Prag
);
2505 end Build_Pre_Post_Condition
;
2509 Loc
: constant Source_Ptr
:= Sloc
(Subp
);
2510 Typ
: constant Entity_Id
:= Etype
(Formal
);
2514 -- Start of processing for Add_Validity_Check
2517 -- For scalars, generate 'Valid test
2519 if Is_Scalar_Type
(Typ
) then
2522 -- For any non-scalar with scalar parts, generate 'Valid_Scalars test
2524 elsif Scalar_Part_Present
(Typ
) then
2525 Nam
:= Name_Valid_Scalars
;
2527 -- No test needed for other cases (no scalars to test)
2533 -- Step 1: Create the expression to verify the validity of the
2536 Check
:= New_Occurrence_Of
(Formal
, Loc
);
2538 -- When processing a function result, use 'Result. Generate
2543 Make_Attribute_Reference
(Loc
,
2545 Attribute_Name
=> Name_Result
);
2549 -- Context['Result]'Valid[_Scalars]
2552 Make_Attribute_Reference
(Loc
,
2554 Attribute_Name
=> Nam
);
2556 -- Step 2: Create a pre or post condition pragma
2558 Build_Pre_Post_Condition
(Check
);
2559 end Add_Validity_Check
;
2564 Subp_Spec
: Node_Id
;
2566 -- Start of processing for Apply_Parameter_Validity_Checks
2569 -- Extract the subprogram specification and declaration nodes
2571 Subp_Spec
:= Parent
(Subp
);
2573 if Nkind
(Subp_Spec
) = N_Defining_Program_Unit_Name
then
2574 Subp_Spec
:= Parent
(Subp_Spec
);
2577 Subp_Decl
:= Parent
(Subp_Spec
);
2579 if not Comes_From_Source
(Subp
)
2581 -- Do not process formal subprograms because the corresponding actual
2582 -- will receive the proper checks when the instance is analyzed.
2584 or else Is_Formal_Subprogram
(Subp
)
2586 -- Do not process imported subprograms since pre and postconditions
2587 -- are never verified on routines coming from a different language.
2589 or else Is_Imported
(Subp
)
2590 or else Is_Intrinsic_Subprogram
(Subp
)
2592 -- The PPC pragmas generated by this routine do not correspond to
2593 -- source aspects, therefore they cannot be applied to abstract
2596 or else Nkind
(Subp_Decl
) = N_Abstract_Subprogram_Declaration
2598 -- Do not consider subprogram renaminds because the renamed entity
2599 -- already has the proper PPC pragmas.
2601 or else Nkind
(Subp_Decl
) = N_Subprogram_Renaming_Declaration
2603 -- Do not process null procedures because there is no benefit of
2604 -- adding the checks to a no action routine.
2606 or else (Nkind
(Subp_Spec
) = N_Procedure_Specification
2607 and then Null_Present
(Subp_Spec
))
2612 -- Inspect all the formals applying aliasing and scalar initialization
2613 -- checks where applicable.
2615 Formal
:= First_Formal
(Subp
);
2616 while Present
(Formal
) loop
2618 -- Generate the following scalar initialization checks for each
2619 -- formal parameter:
2621 -- mode IN - Pre => Formal'Valid[_Scalars]
2622 -- mode IN OUT - Pre, Post => Formal'Valid[_Scalars]
2623 -- mode OUT - Post => Formal'Valid[_Scalars]
2625 if Check_Validity_Of_Parameters
then
2626 if Ekind_In
(Formal
, E_In_Parameter
, E_In_Out_Parameter
) then
2627 Add_Validity_Check
(Formal
, Name_Precondition
, False);
2630 if Ekind_In
(Formal
, E_In_Out_Parameter
, E_Out_Parameter
) then
2631 Add_Validity_Check
(Formal
, Name_Postcondition
, False);
2635 Next_Formal
(Formal
);
2638 -- Generate following scalar initialization check for function result:
2640 -- Post => Subp'Result'Valid[_Scalars]
2642 if Check_Validity_Of_Parameters
and then Ekind
(Subp
) = E_Function
then
2643 Add_Validity_Check
(Subp
, Name_Postcondition
, True);
2645 end Apply_Parameter_Validity_Checks
;
2647 ---------------------------
2648 -- Apply_Predicate_Check --
2649 ---------------------------
2651 procedure Apply_Predicate_Check
2654 Fun
: Entity_Id
:= Empty
)
2659 if Predicate_Checks_Suppressed
(Empty
) then
2662 elsif Predicates_Ignored
(Typ
) then
2665 elsif Present
(Predicate_Function
(Typ
)) then
2667 while Present
(S
) and then not Is_Subprogram
(S
) loop
2671 -- A predicate check does not apply within internally generated
2672 -- subprograms, such as TSS functions.
2674 if Within_Internal_Subprogram
then
2677 -- If the check appears within the predicate function itself, it
2678 -- means that the user specified a check whose formal is the
2679 -- predicated subtype itself, rather than some covering type. This
2680 -- is likely to be a common error, and thus deserves a warning.
2682 elsif Present
(S
) and then S
= Predicate_Function
(Typ
) then
2684 ("predicate check includes a call to& that requires a "
2685 & "predicate check??", Parent
(N
), Fun
);
2687 ("\this will result in infinite recursion??", Parent
(N
));
2689 if Is_First_Subtype
(Typ
) then
2691 ("\use an explicit subtype of& to carry the predicate",
2696 Make_Raise_Storage_Error
(Sloc
(N
),
2697 Reason
=> SE_Infinite_Recursion
));
2699 -- Here for normal case of predicate active
2702 -- If the type has a static predicate and the expression is known
2703 -- at compile time, see if the expression satisfies the predicate.
2705 Check_Expression_Against_Static_Predicate
(N
, Typ
);
2707 if not Expander_Active
then
2711 -- For an entity of the type, generate a call to the predicate
2712 -- function, unless its type is an actual subtype, which is not
2713 -- visible outside of the enclosing subprogram.
2715 if Is_Entity_Name
(N
)
2716 and then not Is_Actual_Subtype
(Typ
)
2719 Make_Predicate_Check
2720 (Typ
, New_Occurrence_Of
(Entity
(N
), Sloc
(N
))));
2722 -- If the expression is not an entity it may have side effects,
2723 -- and the following call will create an object declaration for
2724 -- it. We disable checks during its analysis, to prevent an
2725 -- infinite recursion.
2727 -- If the prefix is an aggregate in an assignment, apply the
2728 -- check to the LHS after assignment, rather than create a
2729 -- redundant temporary. This is only necessary in rare cases
2730 -- of array types (including strings) initialized with an
2731 -- aggregate with an "others" clause, either coming from source
2732 -- or generated by an Initialize_Scalars pragma.
2734 elsif Nkind
(N
) = N_Aggregate
2735 and then Nkind
(Parent
(N
)) = N_Assignment_Statement
2737 Insert_Action_After
(Parent
(N
),
2738 Make_Predicate_Check
2739 (Typ
, Duplicate_Subexpr
(Name
(Parent
(N
)))));
2743 Make_Predicate_Check
2744 (Typ
, Duplicate_Subexpr
(N
)), Suppress
=> All_Checks
);
2748 end Apply_Predicate_Check
;
2750 -----------------------
2751 -- Apply_Range_Check --
2752 -----------------------
2754 procedure Apply_Range_Check
2756 Target_Typ
: Entity_Id
;
2757 Source_Typ
: Entity_Id
:= Empty
)
2760 Apply_Selected_Range_Checks
2761 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
2762 end Apply_Range_Check
;
2764 ------------------------------
2765 -- Apply_Scalar_Range_Check --
2766 ------------------------------
2768 -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag
2769 -- off if it is already set on.
2771 procedure Apply_Scalar_Range_Check
2773 Target_Typ
: Entity_Id
;
2774 Source_Typ
: Entity_Id
:= Empty
;
2775 Fixed_Int
: Boolean := False)
2777 Parnt
: constant Node_Id
:= Parent
(Expr
);
2779 Arr
: Node_Id
:= Empty
; -- initialize to prevent warning
2780 Arr_Typ
: Entity_Id
:= Empty
; -- initialize to prevent warning
2782 Is_Subscr_Ref
: Boolean;
2783 -- Set true if Expr is a subscript
2785 Is_Unconstrained_Subscr_Ref
: Boolean;
2786 -- Set true if Expr is a subscript of an unconstrained array. In this
2787 -- case we do not attempt to do an analysis of the value against the
2788 -- range of the subscript, since we don't know the actual subtype.
2791 -- Set to True if Expr should be regarded as a real value even though
2792 -- the type of Expr might be discrete.
2794 procedure Bad_Value
(Warn
: Boolean := False);
2795 -- Procedure called if value is determined to be out of range. Warn is
2796 -- True to force a warning instead of an error, even when SPARK_Mode is
2803 procedure Bad_Value
(Warn
: Boolean := False) is
2805 Apply_Compile_Time_Constraint_Error
2806 (Expr
, "value not in range of}??", CE_Range_Check_Failed
,
2812 -- Start of processing for Apply_Scalar_Range_Check
2815 -- Return if check obviously not needed
2818 -- Not needed inside generic
2822 -- Not needed if previous error
2824 or else Target_Typ
= Any_Type
2825 or else Nkind
(Expr
) = N_Error
2827 -- Not needed for non-scalar type
2829 or else not Is_Scalar_Type
(Target_Typ
)
2831 -- Not needed if we know node raises CE already
2833 or else Raises_Constraint_Error
(Expr
)
2838 -- Now, see if checks are suppressed
2841 Is_List_Member
(Expr
) and then Nkind
(Parnt
) = N_Indexed_Component
;
2843 if Is_Subscr_Ref
then
2844 Arr
:= Prefix
(Parnt
);
2845 Arr_Typ
:= Get_Actual_Subtype_If_Available
(Arr
);
2847 if Is_Access_Type
(Arr_Typ
) then
2848 Arr_Typ
:= Designated_Type
(Arr_Typ
);
2852 if not Do_Range_Check
(Expr
) then
2854 -- Subscript reference. Check for Index_Checks suppressed
2856 if Is_Subscr_Ref
then
2858 -- Check array type and its base type
2860 if Index_Checks_Suppressed
(Arr_Typ
)
2861 or else Index_Checks_Suppressed
(Base_Type
(Arr_Typ
))
2865 -- Check array itself if it is an entity name
2867 elsif Is_Entity_Name
(Arr
)
2868 and then Index_Checks_Suppressed
(Entity
(Arr
))
2872 -- Check expression itself if it is an entity name
2874 elsif Is_Entity_Name
(Expr
)
2875 and then Index_Checks_Suppressed
(Entity
(Expr
))
2880 -- All other cases, check for Range_Checks suppressed
2883 -- Check target type and its base type
2885 if Range_Checks_Suppressed
(Target_Typ
)
2886 or else Range_Checks_Suppressed
(Base_Type
(Target_Typ
))
2890 -- Check expression itself if it is an entity name
2892 elsif Is_Entity_Name
(Expr
)
2893 and then Range_Checks_Suppressed
(Entity
(Expr
))
2897 -- If Expr is part of an assignment statement, then check left
2898 -- side of assignment if it is an entity name.
2900 elsif Nkind
(Parnt
) = N_Assignment_Statement
2901 and then Is_Entity_Name
(Name
(Parnt
))
2902 and then Range_Checks_Suppressed
(Entity
(Name
(Parnt
)))
2909 -- Do not set range checks if they are killed
2911 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
2912 and then Kill_Range_Check
(Expr
)
2917 -- Do not set range checks for any values from System.Scalar_Values
2918 -- since the whole idea of such values is to avoid checking them.
2920 if Is_Entity_Name
(Expr
)
2921 and then Is_RTU
(Scope
(Entity
(Expr
)), System_Scalar_Values
)
2926 -- Now see if we need a check
2928 if No
(Source_Typ
) then
2929 S_Typ
:= Etype
(Expr
);
2931 S_Typ
:= Source_Typ
;
2934 if not Is_Scalar_Type
(S_Typ
) or else S_Typ
= Any_Type
then
2938 Is_Unconstrained_Subscr_Ref
:=
2939 Is_Subscr_Ref
and then not Is_Constrained
(Arr_Typ
);
2941 -- Special checks for floating-point type
2943 if Is_Floating_Point_Type
(S_Typ
) then
2945 -- Always do a range check if the source type includes infinities and
2946 -- the target type does not include infinities. We do not do this if
2947 -- range checks are killed.
2948 -- If the expression is a literal and the bounds of the type are
2949 -- static constants it may be possible to optimize the check.
2951 if Has_Infinities
(S_Typ
)
2952 and then not Has_Infinities
(Target_Typ
)
2954 -- If the expression is a literal and the bounds of the type are
2955 -- static constants it may be possible to optimize the check.
2957 if Nkind
(Expr
) = N_Real_Literal
then
2959 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
2960 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
2963 if Compile_Time_Known_Value
(Tlo
)
2964 and then Compile_Time_Known_Value
(Thi
)
2965 and then Expr_Value_R
(Expr
) >= Expr_Value_R
(Tlo
)
2966 and then Expr_Value_R
(Expr
) <= Expr_Value_R
(Thi
)
2970 Enable_Range_Check
(Expr
);
2975 Enable_Range_Check
(Expr
);
2980 -- Return if we know expression is definitely in the range of the target
2981 -- type as determined by Determine_Range. Right now we only do this for
2982 -- discrete types, and not fixed-point or floating-point types.
2984 -- The additional less-precise tests below catch these cases
2986 -- In GNATprove_Mode, also deal with the case of a conversion from
2987 -- floating-point to integer. It is only possible because analysis
2988 -- in GNATprove rules out the possibility of a NaN or infinite value.
2990 -- Note: skip this if we are given a source_typ, since the point of
2991 -- supplying a Source_Typ is to stop us looking at the expression.
2992 -- We could sharpen this test to be out parameters only ???
2994 if Is_Discrete_Type
(Target_Typ
)
2995 and then (Is_Discrete_Type
(Etype
(Expr
))
2996 or else (GNATprove_Mode
2997 and then Is_Floating_Point_Type
(Etype
(Expr
))))
2998 and then not Is_Unconstrained_Subscr_Ref
2999 and then No
(Source_Typ
)
3002 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
3003 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
3006 if Compile_Time_Known_Value
(Tlo
)
3007 and then Compile_Time_Known_Value
(Thi
)
3010 OK
: Boolean := False; -- initialize to prevent warning
3011 Hiv
: constant Uint
:= Expr_Value
(Thi
);
3012 Lov
: constant Uint
:= Expr_Value
(Tlo
);
3013 Hi
: Uint
:= No_Uint
;
3014 Lo
: Uint
:= No_Uint
;
3017 -- If range is null, we for sure have a constraint error (we
3018 -- don't even need to look at the value involved, since all
3019 -- possible values will raise CE).
3023 -- When SPARK_Mode is On, force a warning instead of
3024 -- an error in that case, as this likely corresponds
3025 -- to deactivated code.
3027 Bad_Value
(Warn
=> SPARK_Mode
= On
);
3029 -- In GNATprove mode, we enable the range check so that
3030 -- GNATprove will issue a message if it cannot be proved.
3032 if GNATprove_Mode
then
3033 Enable_Range_Check
(Expr
);
3039 -- Otherwise determine range of value
3041 if Is_Discrete_Type
(Etype
(Expr
)) then
3043 (Expr
, OK
, Lo
, Hi
, Assume_Valid
=> True);
3045 -- When converting a float to an integer type, determine the
3046 -- range in real first, and then convert the bounds using
3047 -- UR_To_Uint which correctly rounds away from zero when
3048 -- half way between two integers, as required by normal
3049 -- Ada 95 rounding semantics. It is only possible because
3050 -- analysis in GNATprove rules out the possibility of a NaN
3051 -- or infinite value.
3053 elsif GNATprove_Mode
3054 and then Is_Floating_Point_Type
(Etype
(Expr
))
3062 (Expr
, OK
, Lor
, Hir
, Assume_Valid
=> True);
3065 Lo
:= UR_To_Uint
(Lor
);
3066 Hi
:= UR_To_Uint
(Hir
);
3073 -- If definitely in range, all OK
3075 if Lo
>= Lov
and then Hi
<= Hiv
then
3078 -- If definitely not in range, warn
3080 elsif Lov
> Hi
or else Hiv
< Lo
then
3082 -- Ignore out of range values for System.Priority in
3083 -- CodePeer mode since the actual target compiler may
3084 -- provide a wider range.
3086 if not CodePeer_Mode
3087 or else Target_Typ
/= RTE
(RE_Priority
)
3094 -- Otherwise we don't know
3106 Is_Floating_Point_Type
(S_Typ
)
3107 or else (Is_Fixed_Point_Type
(S_Typ
) and then not Fixed_Int
);
3109 -- Check if we can determine at compile time whether Expr is in the
3110 -- range of the target type. Note that if S_Typ is within the bounds
3111 -- of Target_Typ then this must be the case. This check is meaningful
3112 -- only if this is not a conversion between integer and real types.
3114 if not Is_Unconstrained_Subscr_Ref
3115 and then Is_Discrete_Type
(S_Typ
) = Is_Discrete_Type
(Target_Typ
)
3117 (In_Subrange_Of
(S_Typ
, Target_Typ
, Fixed_Int
)
3119 -- Also check if the expression itself is in the range of the
3120 -- target type if it is a known at compile time value. We skip
3121 -- this test if S_Typ is set since for OUT and IN OUT parameters
3122 -- the Expr itself is not relevant to the checking.
3126 and then Is_In_Range
(Expr
, Target_Typ
,
3127 Assume_Valid
=> True,
3128 Fixed_Int
=> Fixed_Int
,
3129 Int_Real
=> Int_Real
)))
3133 elsif Is_Out_Of_Range
(Expr
, Target_Typ
,
3134 Assume_Valid
=> True,
3135 Fixed_Int
=> Fixed_Int
,
3136 Int_Real
=> Int_Real
)
3141 -- Floating-point case
3142 -- In the floating-point case, we only do range checks if the type is
3143 -- constrained. We definitely do NOT want range checks for unconstrained
3144 -- types, since we want to have infinities, except when
3145 -- Check_Float_Overflow is set.
3147 elsif Is_Floating_Point_Type
(S_Typ
) then
3148 if Is_Constrained
(S_Typ
) or else Check_Float_Overflow
then
3149 Enable_Range_Check
(Expr
);
3152 -- For all other cases we enable a range check unconditionally
3155 Enable_Range_Check
(Expr
);
3158 end Apply_Scalar_Range_Check
;
3160 ----------------------------------
3161 -- Apply_Selected_Length_Checks --
3162 ----------------------------------
3164 procedure Apply_Selected_Length_Checks
3166 Target_Typ
: Entity_Id
;
3167 Source_Typ
: Entity_Id
;
3168 Do_Static
: Boolean)
3170 Checks_On
: constant Boolean :=
3171 not Index_Checks_Suppressed
(Target_Typ
)
3173 not Length_Checks_Suppressed
(Target_Typ
);
3175 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
3179 R_Result
: Check_Result
;
3182 -- Only apply checks when generating code
3184 -- Note: this means that we lose some useful warnings if the expander
3187 if not Expander_Active
then
3192 Selected_Length_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
3194 for J
in 1 .. 2 loop
3195 R_Cno
:= R_Result
(J
);
3196 exit when No
(R_Cno
);
3198 -- A length check may mention an Itype which is attached to a
3199 -- subsequent node. At the top level in a package this can cause
3200 -- an order-of-elaboration problem, so we make sure that the itype
3201 -- is referenced now.
3203 if Ekind
(Current_Scope
) = E_Package
3204 and then Is_Compilation_Unit
(Current_Scope
)
3206 Ensure_Defined
(Target_Typ
, Ck_Node
);
3208 if Present
(Source_Typ
) then
3209 Ensure_Defined
(Source_Typ
, Ck_Node
);
3211 elsif Is_Itype
(Etype
(Ck_Node
)) then
3212 Ensure_Defined
(Etype
(Ck_Node
), Ck_Node
);
3216 -- If the item is a conditional raise of constraint error, then have
3217 -- a look at what check is being performed and ???
3219 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
3220 and then Present
(Condition
(R_Cno
))
3222 Cond
:= Condition
(R_Cno
);
3224 -- Case where node does not now have a dynamic check
3226 if not Has_Dynamic_Length_Check
(Ck_Node
) then
3228 -- If checks are on, just insert the check
3231 Insert_Action
(Ck_Node
, R_Cno
);
3233 if not Do_Static
then
3234 Set_Has_Dynamic_Length_Check
(Ck_Node
);
3237 -- If checks are off, then analyze the length check after
3238 -- temporarily attaching it to the tree in case the relevant
3239 -- condition can be evaluated at compile time. We still want a
3240 -- compile time warning in this case.
3243 Set_Parent
(R_Cno
, Ck_Node
);
3248 -- Output a warning if the condition is known to be True
3250 if Is_Entity_Name
(Cond
)
3251 and then Entity
(Cond
) = Standard_True
3253 Apply_Compile_Time_Constraint_Error
3254 (Ck_Node
, "wrong length for array of}??",
3255 CE_Length_Check_Failed
,
3259 -- If we were only doing a static check, or if checks are not
3260 -- on, then we want to delete the check, since it is not needed.
3261 -- We do this by replacing the if statement by a null statement
3263 elsif Do_Static
or else not Checks_On
then
3264 Remove_Warning_Messages
(R_Cno
);
3265 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
3269 Install_Static_Check
(R_Cno
, Loc
);
3272 end Apply_Selected_Length_Checks
;
3274 ---------------------------------
3275 -- Apply_Selected_Range_Checks --
3276 ---------------------------------
3278 procedure Apply_Selected_Range_Checks
3280 Target_Typ
: Entity_Id
;
3281 Source_Typ
: Entity_Id
;
3282 Do_Static
: Boolean)
3284 Checks_On
: constant Boolean :=
3285 not Index_Checks_Suppressed
(Target_Typ
)
3287 not Range_Checks_Suppressed
(Target_Typ
);
3289 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
3293 R_Result
: Check_Result
;
3296 -- Only apply checks when generating code. In GNATprove mode, we do not
3297 -- apply the checks, but we still call Selected_Range_Checks to possibly
3298 -- issue errors on SPARK code when a run-time error can be detected at
3301 if not GNATprove_Mode
then
3302 if not Expander_Active
or not Checks_On
then
3308 Selected_Range_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
3310 if GNATprove_Mode
then
3314 for J
in 1 .. 2 loop
3315 R_Cno
:= R_Result
(J
);
3316 exit when No
(R_Cno
);
3318 -- The range check requires runtime evaluation. Depending on what its
3319 -- triggering condition is, the check may be converted into a compile
3320 -- time constraint check.
3322 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
3323 and then Present
(Condition
(R_Cno
))
3325 Cond
:= Condition
(R_Cno
);
3327 -- Insert the range check before the related context. Note that
3328 -- this action analyses the triggering condition.
3330 Insert_Action
(Ck_Node
, R_Cno
);
3332 -- This old code doesn't make sense, why is the context flagged as
3333 -- requiring dynamic range checks now in the middle of generating
3336 if not Do_Static
then
3337 Set_Has_Dynamic_Range_Check
(Ck_Node
);
3340 -- The triggering condition evaluates to True, the range check
3341 -- can be converted into a compile time constraint check.
3343 if Is_Entity_Name
(Cond
)
3344 and then Entity
(Cond
) = Standard_True
3346 -- Since an N_Range is technically not an expression, we have
3347 -- to set one of the bounds to C_E and then just flag the
3348 -- N_Range. The warning message will point to the lower bound
3349 -- and complain about a range, which seems OK.
3351 if Nkind
(Ck_Node
) = N_Range
then
3352 Apply_Compile_Time_Constraint_Error
3353 (Low_Bound
(Ck_Node
),
3354 "static range out of bounds of}??",
3355 CE_Range_Check_Failed
,
3359 Set_Raises_Constraint_Error
(Ck_Node
);
3362 Apply_Compile_Time_Constraint_Error
3364 "static value out of range of}??",
3365 CE_Range_Check_Failed
,
3370 -- If we were only doing a static check, or if checks are not
3371 -- on, then we want to delete the check, since it is not needed.
3372 -- We do this by replacing the if statement by a null statement
3374 elsif Do_Static
then
3375 Remove_Warning_Messages
(R_Cno
);
3376 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
3379 -- The range check raises Constraint_Error explicitly
3382 Install_Static_Check
(R_Cno
, Loc
);
3385 end Apply_Selected_Range_Checks
;
3387 -------------------------------
3388 -- Apply_Static_Length_Check --
3389 -------------------------------
3391 procedure Apply_Static_Length_Check
3393 Target_Typ
: Entity_Id
;
3394 Source_Typ
: Entity_Id
:= Empty
)
3397 Apply_Selected_Length_Checks
3398 (Expr
, Target_Typ
, Source_Typ
, Do_Static
=> True);
3399 end Apply_Static_Length_Check
;
3401 -------------------------------------
3402 -- Apply_Subscript_Validity_Checks --
3403 -------------------------------------
3405 procedure Apply_Subscript_Validity_Checks
(Expr
: Node_Id
) is
3409 pragma Assert
(Nkind
(Expr
) = N_Indexed_Component
);
3411 -- Loop through subscripts
3413 Sub
:= First
(Expressions
(Expr
));
3414 while Present
(Sub
) loop
3416 -- Check one subscript. Note that we do not worry about enumeration
3417 -- type with holes, since we will convert the value to a Pos value
3418 -- for the subscript, and that convert will do the necessary validity
3421 Ensure_Valid
(Sub
, Holes_OK
=> True);
3423 -- Move to next subscript
3427 end Apply_Subscript_Validity_Checks
;
3429 ----------------------------------
3430 -- Apply_Type_Conversion_Checks --
3431 ----------------------------------
3433 procedure Apply_Type_Conversion_Checks
(N
: Node_Id
) is
3434 Target_Type
: constant Entity_Id
:= Etype
(N
);
3435 Target_Base
: constant Entity_Id
:= Base_Type
(Target_Type
);
3436 Expr
: constant Node_Id
:= Expression
(N
);
3438 Expr_Type
: constant Entity_Id
:= Underlying_Type
(Etype
(Expr
));
3439 -- Note: if Etype (Expr) is a private type without discriminants, its
3440 -- full view might have discriminants with defaults, so we need the
3441 -- full view here to retrieve the constraints.
3444 if Inside_A_Generic
then
3447 -- Skip these checks if serious errors detected, there are some nasty
3448 -- situations of incomplete trees that blow things up.
3450 elsif Serious_Errors_Detected
> 0 then
3453 -- Never generate discriminant checks for Unchecked_Union types
3455 elsif Present
(Expr_Type
)
3456 and then Is_Unchecked_Union
(Expr_Type
)
3460 -- Scalar type conversions of the form Target_Type (Expr) require a
3461 -- range check if we cannot be sure that Expr is in the base type of
3462 -- Target_Typ and also that Expr is in the range of Target_Typ. These
3463 -- are not quite the same condition from an implementation point of
3464 -- view, but clearly the second includes the first.
3466 elsif Is_Scalar_Type
(Target_Type
) then
3468 Conv_OK
: constant Boolean := Conversion_OK
(N
);
3469 -- If the Conversion_OK flag on the type conversion is set and no
3470 -- floating-point type is involved in the type conversion then
3471 -- fixed-point values must be read as integral values.
3473 Float_To_Int
: constant Boolean :=
3474 Is_Floating_Point_Type
(Expr_Type
)
3475 and then Is_Integer_Type
(Target_Type
);
3478 if not Overflow_Checks_Suppressed
(Target_Base
)
3479 and then not Overflow_Checks_Suppressed
(Target_Type
)
3481 In_Subrange_Of
(Expr_Type
, Target_Base
, Fixed_Int
=> Conv_OK
)
3482 and then not Float_To_Int
3484 -- A small optimization: the attribute 'Pos applied to an
3485 -- enumeration type has a known range, even though its type is
3486 -- Universal_Integer. So in numeric conversions it is usually
3487 -- within range of the target integer type. Use the static
3488 -- bounds of the base types to check. Disable this optimization
3489 -- in case of a generic formal discrete type, because we don't
3490 -- necessarily know the upper bound yet.
3492 if Nkind
(Expr
) = N_Attribute_Reference
3493 and then Attribute_Name
(Expr
) = Name_Pos
3494 and then Is_Enumeration_Type
(Etype
(Prefix
(Expr
)))
3495 and then not Is_Generic_Type
(Etype
(Prefix
(Expr
)))
3496 and then Is_Integer_Type
(Target_Type
)
3499 Enum_T
: constant Entity_Id
:=
3500 Root_Type
(Etype
(Prefix
(Expr
)));
3501 Int_T
: constant Entity_Id
:= Base_Type
(Target_Type
);
3502 Last_I
: constant Uint
:=
3503 Intval
(High_Bound
(Scalar_Range
(Int_T
)));
3507 -- Character types have no explicit literals, so we use
3508 -- the known number of characters in the type.
3510 if Root_Type
(Enum_T
) = Standard_Character
then
3511 Last_E
:= UI_From_Int
(255);
3513 elsif Enum_T
= Standard_Wide_Character
3514 or else Enum_T
= Standard_Wide_Wide_Character
3516 Last_E
:= UI_From_Int
(65535);
3521 (Entity
(High_Bound
(Scalar_Range
(Enum_T
))));
3524 if Last_E
<= Last_I
then
3528 Activate_Overflow_Check
(N
);
3533 Activate_Overflow_Check
(N
);
3537 if not Range_Checks_Suppressed
(Target_Type
)
3538 and then not Range_Checks_Suppressed
(Expr_Type
)
3541 and then not GNATprove_Mode
3543 Apply_Float_Conversion_Check
(Expr
, Target_Type
);
3545 Apply_Scalar_Range_Check
3546 (Expr
, Target_Type
, Fixed_Int
=> Conv_OK
);
3548 -- If the target type has predicates, we need to indicate
3549 -- the need for a check, even if Determine_Range finds that
3550 -- the value is within bounds. This may be the case e.g for
3551 -- a division with a constant denominator.
3553 if Has_Predicates
(Target_Type
) then
3554 Enable_Range_Check
(Expr
);
3560 elsif Comes_From_Source
(N
)
3561 and then not Discriminant_Checks_Suppressed
(Target_Type
)
3562 and then Is_Record_Type
(Target_Type
)
3563 and then Is_Derived_Type
(Target_Type
)
3564 and then not Is_Tagged_Type
(Target_Type
)
3565 and then not Is_Constrained
(Target_Type
)
3566 and then Present
(Stored_Constraint
(Target_Type
))
3568 -- An unconstrained derived type may have inherited discriminant.
3569 -- Build an actual discriminant constraint list using the stored
3570 -- constraint, to verify that the expression of the parent type
3571 -- satisfies the constraints imposed by the (unconstrained) derived
3572 -- type. This applies to value conversions, not to view conversions
3576 Loc
: constant Source_Ptr
:= Sloc
(N
);
3578 Constraint
: Elmt_Id
;
3579 Discr_Value
: Node_Id
;
3582 New_Constraints
: constant Elist_Id
:= New_Elmt_List
;
3583 Old_Constraints
: constant Elist_Id
:=
3584 Discriminant_Constraint
(Expr_Type
);
3587 Constraint
:= First_Elmt
(Stored_Constraint
(Target_Type
));
3588 while Present
(Constraint
) loop
3589 Discr_Value
:= Node
(Constraint
);
3591 if Is_Entity_Name
(Discr_Value
)
3592 and then Ekind
(Entity
(Discr_Value
)) = E_Discriminant
3594 Discr
:= Corresponding_Discriminant
(Entity
(Discr_Value
));
3597 and then Scope
(Discr
) = Base_Type
(Expr_Type
)
3599 -- Parent is constrained by new discriminant. Obtain
3600 -- Value of original discriminant in expression. If the
3601 -- new discriminant has been used to constrain more than
3602 -- one of the stored discriminants, this will provide the
3603 -- required consistency check.
3606 (Make_Selected_Component
(Loc
,
3608 Duplicate_Subexpr_No_Checks
3609 (Expr
, Name_Req
=> True),
3611 Make_Identifier
(Loc
, Chars
(Discr
))),
3615 -- Discriminant of more remote ancestor ???
3620 -- Derived type definition has an explicit value for this
3621 -- stored discriminant.
3625 (Duplicate_Subexpr_No_Checks
(Discr_Value
),
3629 Next_Elmt
(Constraint
);
3632 -- Use the unconstrained expression type to retrieve the
3633 -- discriminants of the parent, and apply momentarily the
3634 -- discriminant constraint synthesized above.
3636 Set_Discriminant_Constraint
(Expr_Type
, New_Constraints
);
3637 Cond
:= Build_Discriminant_Checks
(Expr
, Expr_Type
);
3638 Set_Discriminant_Constraint
(Expr_Type
, Old_Constraints
);
3641 Make_Raise_Constraint_Error
(Loc
,
3643 Reason
=> CE_Discriminant_Check_Failed
));
3646 -- For arrays, checks are set now, but conversions are applied during
3647 -- expansion, to take into accounts changes of representation. The
3648 -- checks become range checks on the base type or length checks on the
3649 -- subtype, depending on whether the target type is unconstrained or
3650 -- constrained. Note that the range check is put on the expression of a
3651 -- type conversion, while the length check is put on the type conversion
3654 elsif Is_Array_Type
(Target_Type
) then
3655 if Is_Constrained
(Target_Type
) then
3656 Set_Do_Length_Check
(N
);
3658 Set_Do_Range_Check
(Expr
);
3661 end Apply_Type_Conversion_Checks
;
3663 ----------------------------------------------
3664 -- Apply_Universal_Integer_Attribute_Checks --
3665 ----------------------------------------------
3667 procedure Apply_Universal_Integer_Attribute_Checks
(N
: Node_Id
) is
3668 Loc
: constant Source_Ptr
:= Sloc
(N
);
3669 Typ
: constant Entity_Id
:= Etype
(N
);
3672 if Inside_A_Generic
then
3675 -- Nothing to do if checks are suppressed
3677 elsif Range_Checks_Suppressed
(Typ
)
3678 and then Overflow_Checks_Suppressed
(Typ
)
3682 -- Nothing to do if the attribute does not come from source. The
3683 -- internal attributes we generate of this type do not need checks,
3684 -- and furthermore the attempt to check them causes some circular
3685 -- elaboration orders when dealing with packed types.
3687 elsif not Comes_From_Source
(N
) then
3690 -- If the prefix is a selected component that depends on a discriminant
3691 -- the check may improperly expose a discriminant instead of using
3692 -- the bounds of the object itself. Set the type of the attribute to
3693 -- the base type of the context, so that a check will be imposed when
3694 -- needed (e.g. if the node appears as an index).
3696 elsif Nkind
(Prefix
(N
)) = N_Selected_Component
3697 and then Ekind
(Typ
) = E_Signed_Integer_Subtype
3698 and then Depends_On_Discriminant
(Scalar_Range
(Typ
))
3700 Set_Etype
(N
, Base_Type
(Typ
));
3702 -- Otherwise, replace the attribute node with a type conversion node
3703 -- whose expression is the attribute, retyped to universal integer, and
3704 -- whose subtype mark is the target type. The call to analyze this
3705 -- conversion will set range and overflow checks as required for proper
3706 -- detection of an out of range value.
3709 Set_Etype
(N
, Universal_Integer
);
3710 Set_Analyzed
(N
, True);
3713 Make_Type_Conversion
(Loc
,
3714 Subtype_Mark
=> New_Occurrence_Of
(Typ
, Loc
),
3715 Expression
=> Relocate_Node
(N
)));
3717 Analyze_And_Resolve
(N
, Typ
);
3720 end Apply_Universal_Integer_Attribute_Checks
;
3722 -------------------------------------
3723 -- Atomic_Synchronization_Disabled --
3724 -------------------------------------
3726 -- Note: internally Disable/Enable_Atomic_Synchronization is implemented
3727 -- using a bogus check called Atomic_Synchronization. This is to make it
3728 -- more convenient to get exactly the same semantics as [Un]Suppress.
3730 function Atomic_Synchronization_Disabled
(E
: Entity_Id
) return Boolean is
3732 -- If debug flag d.e is set, always return False, i.e. all atomic sync
3733 -- looks enabled, since it is never disabled.
3735 if Debug_Flag_Dot_E
then
3738 -- If debug flag d.d is set then always return True, i.e. all atomic
3739 -- sync looks disabled, since it always tests True.
3741 elsif Debug_Flag_Dot_D
then
3744 -- If entity present, then check result for that entity
3746 elsif Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
3747 return Is_Check_Suppressed
(E
, Atomic_Synchronization
);
3749 -- Otherwise result depends on current scope setting
3752 return Scope_Suppress
.Suppress
(Atomic_Synchronization
);
3754 end Atomic_Synchronization_Disabled
;
3756 -------------------------------
3757 -- Build_Discriminant_Checks --
3758 -------------------------------
3760 function Build_Discriminant_Checks
3762 T_Typ
: Entity_Id
) return Node_Id
3764 Loc
: constant Source_Ptr
:= Sloc
(N
);
3767 Disc_Ent
: Entity_Id
;
3771 function Aggregate_Discriminant_Val
(Disc
: Entity_Id
) return Node_Id
;
3773 --------------------------------
3774 -- Aggregate_Discriminant_Val --
3775 --------------------------------
3777 function Aggregate_Discriminant_Val
(Disc
: Entity_Id
) return Node_Id
is
3781 -- The aggregate has been normalized with named associations. We use
3782 -- the Chars field to locate the discriminant to take into account
3783 -- discriminants in derived types, which carry the same name as those
3786 Assoc
:= First
(Component_Associations
(N
));
3787 while Present
(Assoc
) loop
3788 if Chars
(First
(Choices
(Assoc
))) = Chars
(Disc
) then
3789 return Expression
(Assoc
);
3795 -- Discriminant must have been found in the loop above
3797 raise Program_Error
;
3798 end Aggregate_Discriminant_Val
;
3800 -- Start of processing for Build_Discriminant_Checks
3803 -- Loop through discriminants evolving the condition
3806 Disc
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
3808 -- For a fully private type, use the discriminants of the parent type
3810 if Is_Private_Type
(T_Typ
)
3811 and then No
(Full_View
(T_Typ
))
3813 Disc_Ent
:= First_Discriminant
(Etype
(Base_Type
(T_Typ
)));
3815 Disc_Ent
:= First_Discriminant
(T_Typ
);
3818 while Present
(Disc
) loop
3819 Dval
:= Node
(Disc
);
3821 if Nkind
(Dval
) = N_Identifier
3822 and then Ekind
(Entity
(Dval
)) = E_Discriminant
3824 Dval
:= New_Occurrence_Of
(Discriminal
(Entity
(Dval
)), Loc
);
3826 Dval
:= Duplicate_Subexpr_No_Checks
(Dval
);
3829 -- If we have an Unchecked_Union node, we can infer the discriminants
3832 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
3834 Get_Discriminant_Value
(
3835 First_Discriminant
(T_Typ
),
3837 Stored_Constraint
(T_Typ
)));
3839 elsif Nkind
(N
) = N_Aggregate
then
3841 Duplicate_Subexpr_No_Checks
3842 (Aggregate_Discriminant_Val
(Disc_Ent
));
3846 Make_Selected_Component
(Loc
,
3848 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
3849 Selector_Name
=> Make_Identifier
(Loc
, Chars
(Disc_Ent
)));
3851 Set_Is_In_Discriminant_Check
(Dref
);
3854 Evolve_Or_Else
(Cond
,
3857 Right_Opnd
=> Dval
));
3860 Next_Discriminant
(Disc_Ent
);
3864 end Build_Discriminant_Checks
;
3870 function Check_Needed
(Nod
: Node_Id
; Check
: Check_Type
) return Boolean is
3877 function Left_Expression
(Op
: Node_Id
) return Node_Id
;
3878 -- Return the relevant expression from the left operand of the given
3879 -- short circuit form: this is LO itself, except if LO is a qualified
3880 -- expression, a type conversion, or an expression with actions, in
3881 -- which case this is Left_Expression (Expression (LO)).
3883 ---------------------
3884 -- Left_Expression --
3885 ---------------------
3887 function Left_Expression
(Op
: Node_Id
) return Node_Id
is
3888 LE
: Node_Id
:= Left_Opnd
(Op
);
3890 while Nkind_In
(LE
, N_Qualified_Expression
,
3892 N_Expression_With_Actions
)
3894 LE
:= Expression
(LE
);
3898 end Left_Expression
;
3900 -- Start of processing for Check_Needed
3903 -- Always check if not simple entity
3905 if Nkind
(Nod
) not in N_Has_Entity
3906 or else not Comes_From_Source
(Nod
)
3911 -- Look up tree for short circuit
3918 -- Done if out of subexpression (note that we allow generated stuff
3919 -- such as itype declarations in this context, to keep the loop going
3920 -- since we may well have generated such stuff in complex situations.
3921 -- Also done if no parent (probably an error condition, but no point
3922 -- in behaving nasty if we find it).
3925 or else (K
not in N_Subexpr
and then Comes_From_Source
(P
))
3929 -- Or/Or Else case, where test is part of the right operand, or is
3930 -- part of one of the actions associated with the right operand, and
3931 -- the left operand is an equality test.
3933 elsif K
= N_Op_Or
then
3934 exit when N
= Right_Opnd
(P
)
3935 and then Nkind
(Left_Expression
(P
)) = N_Op_Eq
;
3937 elsif K
= N_Or_Else
then
3938 exit when (N
= Right_Opnd
(P
)
3941 and then List_Containing
(N
) = Actions
(P
)))
3942 and then Nkind
(Left_Expression
(P
)) = N_Op_Eq
;
3944 -- Similar test for the And/And then case, where the left operand
3945 -- is an inequality test.
3947 elsif K
= N_Op_And
then
3948 exit when N
= Right_Opnd
(P
)
3949 and then Nkind
(Left_Expression
(P
)) = N_Op_Ne
;
3951 elsif K
= N_And_Then
then
3952 exit when (N
= Right_Opnd
(P
)
3955 and then List_Containing
(N
) = Actions
(P
)))
3956 and then Nkind
(Left_Expression
(P
)) = N_Op_Ne
;
3962 -- If we fall through the loop, then we have a conditional with an
3963 -- appropriate test as its left operand, so look further.
3965 L
:= Left_Expression
(P
);
3967 -- L is an "=" or "/=" operator: extract its operands
3969 R
:= Right_Opnd
(L
);
3972 -- Left operand of test must match original variable
3974 if Nkind
(L
) not in N_Has_Entity
or else Entity
(L
) /= Entity
(Nod
) then
3978 -- Right operand of test must be key value (zero or null)
3981 when Access_Check
=>
3982 if not Known_Null
(R
) then
3986 when Division_Check
=>
3987 if not Compile_Time_Known_Value
(R
)
3988 or else Expr_Value
(R
) /= Uint_0
3994 raise Program_Error
;
3997 -- Here we have the optimizable case, warn if not short-circuited
3999 if K
= N_Op_And
or else K
= N_Op_Or
then
4000 Error_Msg_Warn
:= SPARK_Mode
/= On
;
4003 when Access_Check
=>
4004 if GNATprove_Mode
then
4006 ("Constraint_Error might have been raised (access check)",
4010 ("Constraint_Error may be raised (access check)??",
4014 when Division_Check
=>
4015 if GNATprove_Mode
then
4017 ("Constraint_Error might have been raised (zero divide)",
4021 ("Constraint_Error may be raised (zero divide)??",
4026 raise Program_Error
;
4029 if K
= N_Op_And
then
4030 Error_Msg_N
-- CODEFIX
4031 ("use `AND THEN` instead of AND??", P
);
4033 Error_Msg_N
-- CODEFIX
4034 ("use `OR ELSE` instead of OR??", P
);
4037 -- If not short-circuited, we need the check
4041 -- If short-circuited, we can omit the check
4048 -----------------------------------
4049 -- Check_Valid_Lvalue_Subscripts --
4050 -----------------------------------
4052 procedure Check_Valid_Lvalue_Subscripts
(Expr
: Node_Id
) is
4054 -- Skip this if range checks are suppressed
4056 if Range_Checks_Suppressed
(Etype
(Expr
)) then
4059 -- Only do this check for expressions that come from source. We assume
4060 -- that expander generated assignments explicitly include any necessary
4061 -- checks. Note that this is not just an optimization, it avoids
4062 -- infinite recursions.
4064 elsif not Comes_From_Source
(Expr
) then
4067 -- For a selected component, check the prefix
4069 elsif Nkind
(Expr
) = N_Selected_Component
then
4070 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
4073 -- Case of indexed component
4075 elsif Nkind
(Expr
) = N_Indexed_Component
then
4076 Apply_Subscript_Validity_Checks
(Expr
);
4078 -- Prefix may itself be or contain an indexed component, and these
4079 -- subscripts need checking as well.
4081 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
4083 end Check_Valid_Lvalue_Subscripts
;
4085 ----------------------------------
4086 -- Null_Exclusion_Static_Checks --
4087 ----------------------------------
4089 procedure Null_Exclusion_Static_Checks
4091 Comp
: Node_Id
:= Empty
;
4092 Array_Comp
: Boolean := False)
4094 Has_Null
: constant Boolean := Has_Null_Exclusion
(N
);
4095 Kind
: constant Node_Kind
:= Nkind
(N
);
4096 Error_Nod
: Node_Id
;
4102 (Nkind_In
(Kind
, N_Component_Declaration
,
4103 N_Discriminant_Specification
,
4104 N_Function_Specification
,
4105 N_Object_Declaration
,
4106 N_Parameter_Specification
));
4108 if Kind
= N_Function_Specification
then
4109 Typ
:= Etype
(Defining_Entity
(N
));
4111 Typ
:= Etype
(Defining_Identifier
(N
));
4115 when N_Component_Declaration
=>
4116 if Present
(Access_Definition
(Component_Definition
(N
))) then
4117 Error_Nod
:= Component_Definition
(N
);
4119 Error_Nod
:= Subtype_Indication
(Component_Definition
(N
));
4122 when N_Discriminant_Specification
=>
4123 Error_Nod
:= Discriminant_Type
(N
);
4125 when N_Function_Specification
=>
4126 Error_Nod
:= Result_Definition
(N
);
4128 when N_Object_Declaration
=>
4129 Error_Nod
:= Object_Definition
(N
);
4131 when N_Parameter_Specification
=>
4132 Error_Nod
:= Parameter_Type
(N
);
4135 raise Program_Error
;
4140 -- Enforce legality rule 3.10 (13): A null exclusion can only be
4141 -- applied to an access [sub]type.
4143 if not Is_Access_Type
(Typ
) then
4145 ("`NOT NULL` allowed only for an access type", Error_Nod
);
4147 -- Enforce legality rule RM 3.10(14/1): A null exclusion can only
4148 -- be applied to a [sub]type that does not exclude null already.
4150 elsif Can_Never_Be_Null
(Typ
) and then Comes_From_Source
(Typ
) then
4152 ("`NOT NULL` not allowed (& already excludes null)",
4157 -- Check that null-excluding objects are always initialized, except for
4158 -- deferred constants, for which the expression will appear in the full
4161 if Kind
= N_Object_Declaration
4162 and then No
(Expression
(N
))
4163 and then not Constant_Present
(N
)
4164 and then not No_Initialization
(N
)
4166 if Present
(Comp
) then
4168 -- Specialize the warning message to indicate that we are dealing
4169 -- with an uninitialized composite object that has a defaulted
4170 -- null-excluding component.
4172 Error_Msg_Name_1
:= Chars
(Defining_Identifier
(Comp
));
4173 Error_Msg_Name_2
:= Chars
(Defining_Identifier
(N
));
4176 (Compile_Time_Constraint_Error
4179 "(Ada 2005) null-excluding component % of object % must "
4180 & "be initialized??",
4181 Ent
=> Defining_Identifier
(Comp
)));
4183 -- This is a case of an array with null-excluding components, so
4184 -- indicate that in the warning.
4186 elsif Array_Comp
then
4188 (Compile_Time_Constraint_Error
4191 "(Ada 2005) null-excluding array components must "
4192 & "be initialized??",
4193 Ent
=> Defining_Identifier
(N
)));
4195 -- Normal case of object of a null-excluding access type
4198 -- Add an expression that assigns null. This node is needed by
4199 -- Apply_Compile_Time_Constraint_Error, which will replace this
4200 -- with a Constraint_Error node.
4202 Set_Expression
(N
, Make_Null
(Sloc
(N
)));
4203 Set_Etype
(Expression
(N
), Etype
(Defining_Identifier
(N
)));
4205 Apply_Compile_Time_Constraint_Error
4206 (N
=> Expression
(N
),
4208 "(Ada 2005) null-excluding objects must be initialized??",
4209 Reason
=> CE_Null_Not_Allowed
);
4213 -- Check that a null-excluding component, formal or object is not being
4214 -- assigned a null value. Otherwise generate a warning message and
4215 -- replace Expression (N) by an N_Constraint_Error node.
4217 if Kind
/= N_Function_Specification
then
4218 Expr
:= Expression
(N
);
4220 if Present
(Expr
) and then Known_Null
(Expr
) then
4222 when N_Component_Declaration
4223 | N_Discriminant_Specification
4225 Apply_Compile_Time_Constraint_Error
4228 "(Ada 2005) null not allowed in null-excluding "
4230 Reason
=> CE_Null_Not_Allowed
);
4232 when N_Object_Declaration
=>
4233 Apply_Compile_Time_Constraint_Error
4236 "(Ada 2005) null not allowed in null-excluding "
4238 Reason
=> CE_Null_Not_Allowed
);
4240 when N_Parameter_Specification
=>
4241 Apply_Compile_Time_Constraint_Error
4244 "(Ada 2005) null not allowed in null-excluding "
4246 Reason
=> CE_Null_Not_Allowed
);
4253 end Null_Exclusion_Static_Checks
;
4255 ----------------------------------
4256 -- Conditional_Statements_Begin --
4257 ----------------------------------
4259 procedure Conditional_Statements_Begin
is
4261 Saved_Checks_TOS
:= Saved_Checks_TOS
+ 1;
4263 -- If stack overflows, kill all checks, that way we know to simply reset
4264 -- the number of saved checks to zero on return. This should never occur
4267 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
4270 -- In the normal case, we just make a new stack entry saving the current
4271 -- number of saved checks for a later restore.
4274 Saved_Checks_Stack
(Saved_Checks_TOS
) := Num_Saved_Checks
;
4276 if Debug_Flag_CC
then
4277 w
("Conditional_Statements_Begin: Num_Saved_Checks = ",
4281 end Conditional_Statements_Begin
;
4283 --------------------------------
4284 -- Conditional_Statements_End --
4285 --------------------------------
4287 procedure Conditional_Statements_End
is
4289 pragma Assert
(Saved_Checks_TOS
> 0);
4291 -- If the saved checks stack overflowed, then we killed all checks, so
4292 -- setting the number of saved checks back to zero is correct. This
4293 -- should never occur in practice.
4295 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
4296 Num_Saved_Checks
:= 0;
4298 -- In the normal case, restore the number of saved checks from the top
4302 Num_Saved_Checks
:= Saved_Checks_Stack
(Saved_Checks_TOS
);
4304 if Debug_Flag_CC
then
4305 w
("Conditional_Statements_End: Num_Saved_Checks = ",
4310 Saved_Checks_TOS
:= Saved_Checks_TOS
- 1;
4311 end Conditional_Statements_End
;
4313 -------------------------
4314 -- Convert_From_Bignum --
4315 -------------------------
4317 function Convert_From_Bignum
(N
: Node_Id
) return Node_Id
is
4318 Loc
: constant Source_Ptr
:= Sloc
(N
);
4321 pragma Assert
(Is_RTE
(Etype
(N
), RE_Bignum
));
4323 -- Construct call From Bignum
4326 Make_Function_Call
(Loc
,
4328 New_Occurrence_Of
(RTE
(RE_From_Bignum
), Loc
),
4329 Parameter_Associations
=> New_List
(Relocate_Node
(N
)));
4330 end Convert_From_Bignum
;
4332 -----------------------
4333 -- Convert_To_Bignum --
4334 -----------------------
4336 function Convert_To_Bignum
(N
: Node_Id
) return Node_Id
is
4337 Loc
: constant Source_Ptr
:= Sloc
(N
);
4340 -- Nothing to do if Bignum already except call Relocate_Node
4342 if Is_RTE
(Etype
(N
), RE_Bignum
) then
4343 return Relocate_Node
(N
);
4345 -- Otherwise construct call to To_Bignum, converting the operand to the
4346 -- required Long_Long_Integer form.
4349 pragma Assert
(Is_Signed_Integer_Type
(Etype
(N
)));
4351 Make_Function_Call
(Loc
,
4353 New_Occurrence_Of
(RTE
(RE_To_Bignum
), Loc
),
4354 Parameter_Associations
=> New_List
(
4355 Convert_To
(Standard_Long_Long_Integer
, Relocate_Node
(N
))));
4357 end Convert_To_Bignum
;
4359 ---------------------
4360 -- Determine_Range --
4361 ---------------------
4363 Cache_Size
: constant := 2 ** 10;
4364 type Cache_Index
is range 0 .. Cache_Size
- 1;
4365 -- Determine size of below cache (power of 2 is more efficient)
4367 Determine_Range_Cache_N
: array (Cache_Index
) of Node_Id
;
4368 Determine_Range_Cache_V
: array (Cache_Index
) of Boolean;
4369 Determine_Range_Cache_Lo
: array (Cache_Index
) of Uint
;
4370 Determine_Range_Cache_Hi
: array (Cache_Index
) of Uint
;
4371 Determine_Range_Cache_Lo_R
: array (Cache_Index
) of Ureal
;
4372 Determine_Range_Cache_Hi_R
: array (Cache_Index
) of Ureal
;
4373 -- The above arrays are used to implement a small direct cache for
4374 -- Determine_Range and Determine_Range_R calls. Because of the way these
4375 -- subprograms recursively traces subexpressions, and because overflow
4376 -- checking calls the routine on the way up the tree, a quadratic behavior
4377 -- can otherwise be encountered in large expressions. The cache entry for
4378 -- node N is stored in the (N mod Cache_Size) entry, and can be validated
4379 -- by checking the actual node value stored there. The Range_Cache_V array
4380 -- records the setting of Assume_Valid for the cache entry.
4382 procedure Determine_Range
4387 Assume_Valid
: Boolean := False)
4389 Typ
: Entity_Id
:= Etype
(N
);
4390 -- Type to use, may get reset to base type for possibly invalid entity
4394 -- Lo and Hi bounds of left operand
4396 Lo_Right
: Uint
:= No_Uint
;
4397 Hi_Right
: Uint
:= No_Uint
;
4398 -- Lo and Hi bounds of right (or only) operand
4401 -- Temp variable used to hold a bound node
4404 -- High bound of base type of expression
4408 -- Refined values for low and high bounds, after tightening
4411 -- Used in lower level calls to indicate if call succeeded
4413 Cindex
: Cache_Index
;
4414 -- Used to search cache
4419 function OK_Operands
return Boolean;
4420 -- Used for binary operators. Determines the ranges of the left and
4421 -- right operands, and if they are both OK, returns True, and puts
4422 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left.
4428 function OK_Operands
return Boolean is
4431 (Left_Opnd
(N
), OK1
, Lo_Left
, Hi_Left
, Assume_Valid
);
4438 (Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
, Assume_Valid
);
4442 -- Start of processing for Determine_Range
4445 -- Prevent junk warnings by initializing range variables
4452 -- For temporary constants internally generated to remove side effects
4453 -- we must use the corresponding expression to determine the range of
4454 -- the expression. But note that the expander can also generate
4455 -- constants in other cases, including deferred constants.
4457 if Is_Entity_Name
(N
)
4458 and then Nkind
(Parent
(Entity
(N
))) = N_Object_Declaration
4459 and then Ekind
(Entity
(N
)) = E_Constant
4460 and then Is_Internal_Name
(Chars
(Entity
(N
)))
4462 if Present
(Expression
(Parent
(Entity
(N
)))) then
4464 (Expression
(Parent
(Entity
(N
))), OK
, Lo
, Hi
, Assume_Valid
);
4466 elsif Present
(Full_View
(Entity
(N
))) then
4468 (Expression
(Parent
(Full_View
(Entity
(N
)))),
4469 OK
, Lo
, Hi
, Assume_Valid
);
4477 -- If type is not defined, we can't determine its range
4481 -- We don't deal with anything except discrete types
4483 or else not Is_Discrete_Type
(Typ
)
4485 -- Ignore type for which an error has been posted, since range in
4486 -- this case may well be a bogosity deriving from the error. Also
4487 -- ignore if error posted on the reference node.
4489 or else Error_Posted
(N
) or else Error_Posted
(Typ
)
4495 -- For all other cases, we can determine the range
4499 -- If value is compile time known, then the possible range is the one
4500 -- value that we know this expression definitely has.
4502 if Compile_Time_Known_Value
(N
) then
4503 Lo
:= Expr_Value
(N
);
4508 -- Return if already in the cache
4510 Cindex
:= Cache_Index
(N
mod Cache_Size
);
4512 if Determine_Range_Cache_N
(Cindex
) = N
4514 Determine_Range_Cache_V
(Cindex
) = Assume_Valid
4516 Lo
:= Determine_Range_Cache_Lo
(Cindex
);
4517 Hi
:= Determine_Range_Cache_Hi
(Cindex
);
4521 -- Otherwise, start by finding the bounds of the type of the expression,
4522 -- the value cannot be outside this range (if it is, then we have an
4523 -- overflow situation, which is a separate check, we are talking here
4524 -- only about the expression value).
4526 -- First a check, never try to find the bounds of a generic type, since
4527 -- these bounds are always junk values, and it is only valid to look at
4528 -- the bounds in an instance.
4530 if Is_Generic_Type
(Typ
) then
4535 -- First step, change to use base type unless we know the value is valid
4537 if (Is_Entity_Name
(N
) and then Is_Known_Valid
(Entity
(N
)))
4538 or else Assume_No_Invalid_Values
4539 or else Assume_Valid
4543 Typ
:= Underlying_Type
(Base_Type
(Typ
));
4546 -- Retrieve the base type. Handle the case where the base type is a
4547 -- private enumeration type.
4549 Btyp
:= Base_Type
(Typ
);
4551 if Is_Private_Type
(Btyp
) and then Present
(Full_View
(Btyp
)) then
4552 Btyp
:= Full_View
(Btyp
);
4555 -- We use the actual bound unless it is dynamic, in which case use the
4556 -- corresponding base type bound if possible. If we can't get a bound
4557 -- then we figure we can't determine the range (a peculiar case, that
4558 -- perhaps cannot happen, but there is no point in bombing in this
4559 -- optimization circuit.
4561 -- First the low bound
4563 Bound
:= Type_Low_Bound
(Typ
);
4565 if Compile_Time_Known_Value
(Bound
) then
4566 Lo
:= Expr_Value
(Bound
);
4568 elsif Compile_Time_Known_Value
(Type_Low_Bound
(Btyp
)) then
4569 Lo
:= Expr_Value
(Type_Low_Bound
(Btyp
));
4576 -- Now the high bound
4578 Bound
:= Type_High_Bound
(Typ
);
4580 -- We need the high bound of the base type later on, and this should
4581 -- always be compile time known. Again, it is not clear that this
4582 -- can ever be false, but no point in bombing.
4584 if Compile_Time_Known_Value
(Type_High_Bound
(Btyp
)) then
4585 Hbound
:= Expr_Value
(Type_High_Bound
(Btyp
));
4593 -- If we have a static subtype, then that may have a tighter bound so
4594 -- use the upper bound of the subtype instead in this case.
4596 if Compile_Time_Known_Value
(Bound
) then
4597 Hi
:= Expr_Value
(Bound
);
4600 -- We may be able to refine this value in certain situations. If any
4601 -- refinement is possible, then Lor and Hir are set to possibly tighter
4602 -- bounds, and OK1 is set to True.
4606 -- For unary plus, result is limited by range of operand
4610 (Right_Opnd
(N
), OK1
, Lor
, Hir
, Assume_Valid
);
4612 -- For unary minus, determine range of operand, and negate it
4616 (Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
, Assume_Valid
);
4623 -- For binary addition, get range of each operand and do the
4624 -- addition to get the result range.
4628 Lor
:= Lo_Left
+ Lo_Right
;
4629 Hir
:= Hi_Left
+ Hi_Right
;
4632 -- Division is tricky. The only case we consider is where the right
4633 -- operand is a positive constant, and in this case we simply divide
4634 -- the bounds of the left operand
4638 if Lo_Right
= Hi_Right
4639 and then Lo_Right
> 0
4641 Lor
:= Lo_Left
/ Lo_Right
;
4642 Hir
:= Hi_Left
/ Lo_Right
;
4648 -- For binary subtraction, get range of each operand and do the worst
4649 -- case subtraction to get the result range.
4651 when N_Op_Subtract
=>
4653 Lor
:= Lo_Left
- Hi_Right
;
4654 Hir
:= Hi_Left
- Lo_Right
;
4657 -- For MOD, if right operand is a positive constant, then result must
4658 -- be in the allowable range of mod results.
4662 if Lo_Right
= Hi_Right
4663 and then Lo_Right
/= 0
4665 if Lo_Right
> 0 then
4667 Hir
:= Lo_Right
- 1;
4669 else -- Lo_Right < 0
4670 Lor
:= Lo_Right
+ 1;
4679 -- For REM, if right operand is a positive constant, then result must
4680 -- be in the allowable range of mod results.
4684 if Lo_Right
= Hi_Right
and then Lo_Right
/= 0 then
4686 Dval
: constant Uint
:= (abs Lo_Right
) - 1;
4689 -- The sign of the result depends on the sign of the
4690 -- dividend (but not on the sign of the divisor, hence
4691 -- the abs operation above).
4711 -- Attribute reference cases
4713 when N_Attribute_Reference
=>
4714 case Attribute_Name
(N
) is
4716 -- For Pos/Val attributes, we can refine the range using the
4717 -- possible range of values of the attribute expression.
4723 (First
(Expressions
(N
)), OK1
, Lor
, Hir
, Assume_Valid
);
4725 -- For Length attribute, use the bounds of the corresponding
4726 -- index type to refine the range.
4730 Atyp
: Entity_Id
:= Etype
(Prefix
(N
));
4738 if Is_Access_Type
(Atyp
) then
4739 Atyp
:= Designated_Type
(Atyp
);
4742 -- For string literal, we know exact value
4744 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
4746 Lo
:= String_Literal_Length
(Atyp
);
4747 Hi
:= String_Literal_Length
(Atyp
);
4751 -- Otherwise check for expression given
4753 if No
(Expressions
(N
)) then
4757 UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
4760 Indx
:= First_Index
(Atyp
);
4761 for J
in 2 .. Inum
loop
4762 Indx
:= Next_Index
(Indx
);
4765 -- If the index type is a formal type or derived from
4766 -- one, the bounds are not static.
4768 if Is_Generic_Type
(Root_Type
(Etype
(Indx
))) then
4774 (Type_Low_Bound
(Etype
(Indx
)), OK1
, LL
, LU
,
4779 (Type_High_Bound
(Etype
(Indx
)), OK1
, UL
, UU
,
4784 -- The maximum value for Length is the biggest
4785 -- possible gap between the values of the bounds.
4786 -- But of course, this value cannot be negative.
4788 Hir
:= UI_Max
(Uint_0
, UU
- LL
+ 1);
4790 -- For constrained arrays, the minimum value for
4791 -- Length is taken from the actual value of the
4792 -- bounds, since the index will be exactly of this
4795 if Is_Constrained
(Atyp
) then
4796 Lor
:= UI_Max
(Uint_0
, UL
- LU
+ 1);
4798 -- For an unconstrained array, the minimum value
4799 -- for length is always zero.
4808 -- No special handling for other attributes
4809 -- Probably more opportunities exist here???
4816 when N_Type_Conversion
=>
4818 -- For type conversion from one discrete type to another, we can
4819 -- refine the range using the converted value.
4821 if Is_Discrete_Type
(Etype
(Expression
(N
))) then
4822 Determine_Range
(Expression
(N
), OK1
, Lor
, Hir
, Assume_Valid
);
4824 -- When converting a float to an integer type, determine the range
4825 -- in real first, and then convert the bounds using UR_To_Uint
4826 -- which correctly rounds away from zero when half way between two
4827 -- integers, as required by normal Ada 95 rounding semantics. It
4828 -- is only possible because analysis in GNATprove rules out the
4829 -- possibility of a NaN or infinite value.
4831 elsif GNATprove_Mode
4832 and then Is_Floating_Point_Type
(Etype
(Expression
(N
)))
4835 Lor_Real
, Hir_Real
: Ureal
;
4837 Determine_Range_R
(Expression
(N
), OK1
, Lor_Real
, Hir_Real
,
4841 Lor
:= UR_To_Uint
(Lor_Real
);
4842 Hir
:= UR_To_Uint
(Hir_Real
);
4850 -- Nothing special to do for all other expression kinds
4858 -- At this stage, if OK1 is true, then we know that the actual result of
4859 -- the computed expression is in the range Lor .. Hir. We can use this
4860 -- to restrict the possible range of results.
4864 -- If the refined value of the low bound is greater than the type
4865 -- low bound, then reset it to the more restrictive value. However,
4866 -- we do NOT do this for the case of a modular type where the
4867 -- possible upper bound on the value is above the base type high
4868 -- bound, because that means the result could wrap.
4871 and then not (Is_Modular_Integer_Type
(Typ
) and then Hir
> Hbound
)
4876 -- Similarly, if the refined value of the high bound is less than the
4877 -- value so far, then reset it to the more restrictive value. Again,
4878 -- we do not do this if the refined low bound is negative for a
4879 -- modular type, since this would wrap.
4882 and then not (Is_Modular_Integer_Type
(Typ
) and then Lor
< Uint_0
)
4888 -- Set cache entry for future call and we are all done
4890 Determine_Range_Cache_N
(Cindex
) := N
;
4891 Determine_Range_Cache_V
(Cindex
) := Assume_Valid
;
4892 Determine_Range_Cache_Lo
(Cindex
) := Lo
;
4893 Determine_Range_Cache_Hi
(Cindex
) := Hi
;
4896 -- If any exception occurs, it means that we have some bug in the compiler,
4897 -- possibly triggered by a previous error, or by some unforeseen peculiar
4898 -- occurrence. However, this is only an optimization attempt, so there is
4899 -- really no point in crashing the compiler. Instead we just decide, too
4900 -- bad, we can't figure out a range in this case after all.
4905 -- Debug flag K disables this behavior (useful for debugging)
4907 if Debug_Flag_K
then
4915 end Determine_Range
;
4917 -----------------------
4918 -- Determine_Range_R --
4919 -----------------------
4921 procedure Determine_Range_R
4926 Assume_Valid
: Boolean := False)
4928 Typ
: Entity_Id
:= Etype
(N
);
4929 -- Type to use, may get reset to base type for possibly invalid entity
4933 -- Lo and Hi bounds of left operand
4935 Lo_Right
: Ureal
:= No_Ureal
;
4936 Hi_Right
: Ureal
:= No_Ureal
;
4937 -- Lo and Hi bounds of right (or only) operand
4940 -- Temp variable used to hold a bound node
4943 -- High bound of base type of expression
4947 -- Refined values for low and high bounds, after tightening
4950 -- Used in lower level calls to indicate if call succeeded
4952 Cindex
: Cache_Index
;
4953 -- Used to search cache
4958 function OK_Operands
return Boolean;
4959 -- Used for binary operators. Determines the ranges of the left and
4960 -- right operands, and if they are both OK, returns True, and puts
4961 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left.
4963 function Round_Machine
(B
: Ureal
) return Ureal
;
4964 -- B is a real bound. Round it using mode Round_Even.
4970 function OK_Operands
return Boolean is
4973 (Left_Opnd
(N
), OK1
, Lo_Left
, Hi_Left
, Assume_Valid
);
4980 (Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
, Assume_Valid
);
4988 function Round_Machine
(B
: Ureal
) return Ureal
is
4990 return Machine
(Typ
, B
, Round_Even
, N
);
4993 -- Start of processing for Determine_Range_R
4996 -- Prevent junk warnings by initializing range variables
5003 -- For temporary constants internally generated to remove side effects
5004 -- we must use the corresponding expression to determine the range of
5005 -- the expression. But note that the expander can also generate
5006 -- constants in other cases, including deferred constants.
5008 if Is_Entity_Name
(N
)
5009 and then Nkind
(Parent
(Entity
(N
))) = N_Object_Declaration
5010 and then Ekind
(Entity
(N
)) = E_Constant
5011 and then Is_Internal_Name
(Chars
(Entity
(N
)))
5013 if Present
(Expression
(Parent
(Entity
(N
)))) then
5015 (Expression
(Parent
(Entity
(N
))), OK
, Lo
, Hi
, Assume_Valid
);
5017 elsif Present
(Full_View
(Entity
(N
))) then
5019 (Expression
(Parent
(Full_View
(Entity
(N
)))),
5020 OK
, Lo
, Hi
, Assume_Valid
);
5029 -- If type is not defined, we can't determine its range
5033 -- We don't deal with anything except IEEE floating-point types
5035 or else not Is_Floating_Point_Type
(Typ
)
5036 or else Float_Rep
(Typ
) /= IEEE_Binary
5038 -- Ignore type for which an error has been posted, since range in
5039 -- this case may well be a bogosity deriving from the error. Also
5040 -- ignore if error posted on the reference node.
5042 or else Error_Posted
(N
) or else Error_Posted
(Typ
)
5048 -- For all other cases, we can determine the range
5052 -- If value is compile time known, then the possible range is the one
5053 -- value that we know this expression definitely has.
5055 if Compile_Time_Known_Value
(N
) then
5056 Lo
:= Expr_Value_R
(N
);
5061 -- Return if already in the cache
5063 Cindex
:= Cache_Index
(N
mod Cache_Size
);
5065 if Determine_Range_Cache_N
(Cindex
) = N
5067 Determine_Range_Cache_V
(Cindex
) = Assume_Valid
5069 Lo
:= Determine_Range_Cache_Lo_R
(Cindex
);
5070 Hi
:= Determine_Range_Cache_Hi_R
(Cindex
);
5074 -- Otherwise, start by finding the bounds of the type of the expression,
5075 -- the value cannot be outside this range (if it is, then we have an
5076 -- overflow situation, which is a separate check, we are talking here
5077 -- only about the expression value).
5079 -- First a check, never try to find the bounds of a generic type, since
5080 -- these bounds are always junk values, and it is only valid to look at
5081 -- the bounds in an instance.
5083 if Is_Generic_Type
(Typ
) then
5088 -- First step, change to use base type unless we know the value is valid
5090 if (Is_Entity_Name
(N
) and then Is_Known_Valid
(Entity
(N
)))
5091 or else Assume_No_Invalid_Values
5092 or else Assume_Valid
5096 Typ
:= Underlying_Type
(Base_Type
(Typ
));
5099 -- Retrieve the base type. Handle the case where the base type is a
5102 Btyp
:= Base_Type
(Typ
);
5104 if Is_Private_Type
(Btyp
) and then Present
(Full_View
(Btyp
)) then
5105 Btyp
:= Full_View
(Btyp
);
5108 -- We use the actual bound unless it is dynamic, in which case use the
5109 -- corresponding base type bound if possible. If we can't get a bound
5110 -- then we figure we can't determine the range (a peculiar case, that
5111 -- perhaps cannot happen, but there is no point in bombing in this
5112 -- optimization circuit).
5114 -- First the low bound
5116 Bound
:= Type_Low_Bound
(Typ
);
5118 if Compile_Time_Known_Value
(Bound
) then
5119 Lo
:= Expr_Value_R
(Bound
);
5121 elsif Compile_Time_Known_Value
(Type_Low_Bound
(Btyp
)) then
5122 Lo
:= Expr_Value_R
(Type_Low_Bound
(Btyp
));
5129 -- Now the high bound
5131 Bound
:= Type_High_Bound
(Typ
);
5133 -- We need the high bound of the base type later on, and this should
5134 -- always be compile time known. Again, it is not clear that this
5135 -- can ever be false, but no point in bombing.
5137 if Compile_Time_Known_Value
(Type_High_Bound
(Btyp
)) then
5138 Hbound
:= Expr_Value_R
(Type_High_Bound
(Btyp
));
5146 -- If we have a static subtype, then that may have a tighter bound so
5147 -- use the upper bound of the subtype instead in this case.
5149 if Compile_Time_Known_Value
(Bound
) then
5150 Hi
:= Expr_Value_R
(Bound
);
5153 -- We may be able to refine this value in certain situations. If any
5154 -- refinement is possible, then Lor and Hir are set to possibly tighter
5155 -- bounds, and OK1 is set to True.
5159 -- For unary plus, result is limited by range of operand
5163 (Right_Opnd
(N
), OK1
, Lor
, Hir
, Assume_Valid
);
5165 -- For unary minus, determine range of operand, and negate it
5169 (Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
, Assume_Valid
);
5176 -- For binary addition, get range of each operand and do the
5177 -- addition to get the result range.
5181 Lor
:= Round_Machine
(Lo_Left
+ Lo_Right
);
5182 Hir
:= Round_Machine
(Hi_Left
+ Hi_Right
);
5185 -- For binary subtraction, get range of each operand and do the worst
5186 -- case subtraction to get the result range.
5188 when N_Op_Subtract
=>
5190 Lor
:= Round_Machine
(Lo_Left
- Hi_Right
);
5191 Hir
:= Round_Machine
(Hi_Left
- Lo_Right
);
5194 -- For multiplication, get range of each operand and do the
5195 -- four multiplications to get the result range.
5197 when N_Op_Multiply
=>
5200 M1
: constant Ureal
:= Round_Machine
(Lo_Left
* Lo_Right
);
5201 M2
: constant Ureal
:= Round_Machine
(Lo_Left
* Hi_Right
);
5202 M3
: constant Ureal
:= Round_Machine
(Hi_Left
* Lo_Right
);
5203 M4
: constant Ureal
:= Round_Machine
(Hi_Left
* Hi_Right
);
5206 Lor
:= UR_Min
(UR_Min
(M1
, M2
), UR_Min
(M3
, M4
));
5207 Hir
:= UR_Max
(UR_Max
(M1
, M2
), UR_Max
(M3
, M4
));
5211 -- For division, consider separately the cases where the right
5212 -- operand is positive or negative. Otherwise, the right operand
5213 -- can be arbitrarily close to zero, so the result is likely to
5214 -- be unbounded in one direction, do not attempt to compute it.
5219 -- Right operand is positive
5221 if Lo_Right
> Ureal_0
then
5223 -- If the low bound of the left operand is negative, obtain
5224 -- the overall low bound by dividing it by the smallest
5225 -- value of the right operand, and otherwise by the largest
5226 -- value of the right operand.
5228 if Lo_Left
< Ureal_0
then
5229 Lor
:= Round_Machine
(Lo_Left
/ Lo_Right
);
5231 Lor
:= Round_Machine
(Lo_Left
/ Hi_Right
);
5234 -- If the high bound of the left operand is negative, obtain
5235 -- the overall high bound by dividing it by the largest
5236 -- value of the right operand, and otherwise by the
5237 -- smallest value of the right operand.
5239 if Hi_Left
< Ureal_0
then
5240 Hir
:= Round_Machine
(Hi_Left
/ Hi_Right
);
5242 Hir
:= Round_Machine
(Hi_Left
/ Lo_Right
);
5245 -- Right operand is negative
5247 elsif Hi_Right
< Ureal_0
then
5249 -- If the low bound of the left operand is negative, obtain
5250 -- the overall low bound by dividing it by the largest
5251 -- value of the right operand, and otherwise by the smallest
5252 -- value of the right operand.
5254 if Lo_Left
< Ureal_0
then
5255 Lor
:= Round_Machine
(Lo_Left
/ Hi_Right
);
5257 Lor
:= Round_Machine
(Lo_Left
/ Lo_Right
);
5260 -- If the high bound of the left operand is negative, obtain
5261 -- the overall high bound by dividing it by the smallest
5262 -- value of the right operand, and otherwise by the
5263 -- largest value of the right operand.
5265 if Hi_Left
< Ureal_0
then
5266 Hir
:= Round_Machine
(Hi_Left
/ Lo_Right
);
5268 Hir
:= Round_Machine
(Hi_Left
/ Hi_Right
);
5276 when N_Type_Conversion
=>
5278 -- For type conversion from one floating-point type to another, we
5279 -- can refine the range using the converted value.
5281 if Is_Floating_Point_Type
(Etype
(Expression
(N
))) then
5282 Determine_Range_R
(Expression
(N
), OK1
, Lor
, Hir
, Assume_Valid
);
5284 -- When converting an integer to a floating-point type, determine
5285 -- the range in integer first, and then convert the bounds.
5287 elsif Is_Discrete_Type
(Etype
(Expression
(N
))) then
5294 (Expression
(N
), OK1
, Lor_Int
, Hir_Int
, Assume_Valid
);
5297 Lor
:= Round_Machine
(UR_From_Uint
(Lor_Int
));
5298 Hir
:= Round_Machine
(UR_From_Uint
(Hir_Int
));
5306 -- Nothing special to do for all other expression kinds
5314 -- At this stage, if OK1 is true, then we know that the actual result of
5315 -- the computed expression is in the range Lor .. Hir. We can use this
5316 -- to restrict the possible range of results.
5320 -- If the refined value of the low bound is greater than the type
5321 -- low bound, then reset it to the more restrictive value.
5327 -- Similarly, if the refined value of the high bound is less than the
5328 -- value so far, then reset it to the more restrictive value.
5335 -- Set cache entry for future call and we are all done
5337 Determine_Range_Cache_N
(Cindex
) := N
;
5338 Determine_Range_Cache_V
(Cindex
) := Assume_Valid
;
5339 Determine_Range_Cache_Lo_R
(Cindex
) := Lo
;
5340 Determine_Range_Cache_Hi_R
(Cindex
) := Hi
;
5343 -- If any exception occurs, it means that we have some bug in the compiler,
5344 -- possibly triggered by a previous error, or by some unforeseen peculiar
5345 -- occurrence. However, this is only an optimization attempt, so there is
5346 -- really no point in crashing the compiler. Instead we just decide, too
5347 -- bad, we can't figure out a range in this case after all.
5352 -- Debug flag K disables this behavior (useful for debugging)
5354 if Debug_Flag_K
then
5362 end Determine_Range_R
;
5364 ------------------------------------
5365 -- Discriminant_Checks_Suppressed --
5366 ------------------------------------
5368 function Discriminant_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5371 if Is_Unchecked_Union
(E
) then
5373 elsif Checks_May_Be_Suppressed
(E
) then
5374 return Is_Check_Suppressed
(E
, Discriminant_Check
);
5378 return Scope_Suppress
.Suppress
(Discriminant_Check
);
5379 end Discriminant_Checks_Suppressed
;
5381 --------------------------------
5382 -- Division_Checks_Suppressed --
5383 --------------------------------
5385 function Division_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5387 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
5388 return Is_Check_Suppressed
(E
, Division_Check
);
5390 return Scope_Suppress
.Suppress
(Division_Check
);
5392 end Division_Checks_Suppressed
;
5394 --------------------------------------
5395 -- Duplicated_Tag_Checks_Suppressed --
5396 --------------------------------------
5398 function Duplicated_Tag_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5400 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
5401 return Is_Check_Suppressed
(E
, Duplicated_Tag_Check
);
5403 return Scope_Suppress
.Suppress
(Duplicated_Tag_Check
);
5405 end Duplicated_Tag_Checks_Suppressed
;
5407 -----------------------------------
5408 -- Elaboration_Checks_Suppressed --
5409 -----------------------------------
5411 function Elaboration_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5413 -- The complication in this routine is that if we are in the dynamic
5414 -- model of elaboration, we also check All_Checks, since All_Checks
5415 -- does not set Elaboration_Check explicitly.
5418 if Kill_Elaboration_Checks
(E
) then
5421 elsif Checks_May_Be_Suppressed
(E
) then
5422 if Is_Check_Suppressed
(E
, Elaboration_Check
) then
5425 elsif Dynamic_Elaboration_Checks
then
5426 return Is_Check_Suppressed
(E
, All_Checks
);
5434 if Scope_Suppress
.Suppress
(Elaboration_Check
) then
5437 elsif Dynamic_Elaboration_Checks
then
5438 return Scope_Suppress
.Suppress
(All_Checks
);
5443 end Elaboration_Checks_Suppressed
;
5445 ---------------------------
5446 -- Enable_Overflow_Check --
5447 ---------------------------
5449 procedure Enable_Overflow_Check
(N
: Node_Id
) is
5450 Typ
: constant Entity_Id
:= Base_Type
(Etype
(N
));
5451 Mode
: constant Overflow_Mode_Type
:= Overflow_Check_Mode
;
5459 Do_Ovflow_Check
: Boolean;
5462 if Debug_Flag_CC
then
5463 w
("Enable_Overflow_Check for node ", Int
(N
));
5464 Write_Str
(" Source location = ");
5469 -- No check if overflow checks suppressed for type of node
5471 if Overflow_Checks_Suppressed
(Etype
(N
)) then
5474 -- Nothing to do for unsigned integer types, which do not overflow
5476 elsif Is_Modular_Integer_Type
(Typ
) then
5480 -- This is the point at which processing for STRICT mode diverges
5481 -- from processing for MINIMIZED/ELIMINATED modes. This divergence is
5482 -- probably more extreme that it needs to be, but what is going on here
5483 -- is that when we introduced MINIMIZED/ELIMINATED modes, we wanted
5484 -- to leave the processing for STRICT mode untouched. There were
5485 -- two reasons for this. First it avoided any incompatible change of
5486 -- behavior. Second, it guaranteed that STRICT mode continued to be
5489 -- The big difference is that in STRICT mode there is a fair amount of
5490 -- circuitry to try to avoid setting the Do_Overflow_Check flag if we
5491 -- know that no check is needed. We skip all that in the two new modes,
5492 -- since really overflow checking happens over a whole subtree, and we
5493 -- do the corresponding optimizations later on when applying the checks.
5495 if Mode
in Minimized_Or_Eliminated
then
5496 if not (Overflow_Checks_Suppressed
(Etype
(N
)))
5497 and then not (Is_Entity_Name
(N
)
5498 and then Overflow_Checks_Suppressed
(Entity
(N
)))
5500 Activate_Overflow_Check
(N
);
5503 if Debug_Flag_CC
then
5504 w
("Minimized/Eliminated mode");
5510 -- Remainder of processing is for STRICT case, and is unchanged from
5511 -- earlier versions preceding the addition of MINIMIZED/ELIMINATED.
5513 -- Nothing to do if the range of the result is known OK. We skip this
5514 -- for conversions, since the caller already did the check, and in any
5515 -- case the condition for deleting the check for a type conversion is
5518 if Nkind
(N
) /= N_Type_Conversion
then
5519 Determine_Range
(N
, OK
, Lo
, Hi
, Assume_Valid
=> True);
5521 -- Note in the test below that we assume that the range is not OK
5522 -- if a bound of the range is equal to that of the type. That's not
5523 -- quite accurate but we do this for the following reasons:
5525 -- a) The way that Determine_Range works, it will typically report
5526 -- the bounds of the value as being equal to the bounds of the
5527 -- type, because it either can't tell anything more precise, or
5528 -- does not think it is worth the effort to be more precise.
5530 -- b) It is very unusual to have a situation in which this would
5531 -- generate an unnecessary overflow check (an example would be
5532 -- a subtype with a range 0 .. Integer'Last - 1 to which the
5533 -- literal value one is added).
5535 -- c) The alternative is a lot of special casing in this routine
5536 -- which would partially duplicate Determine_Range processing.
5539 Do_Ovflow_Check
:= True;
5541 -- Note that the following checks are quite deliberately > and <
5542 -- rather than >= and <= as explained above.
5544 if Lo
> Expr_Value
(Type_Low_Bound
(Typ
))
5546 Hi
< Expr_Value
(Type_High_Bound
(Typ
))
5548 Do_Ovflow_Check
:= False;
5550 -- Despite the comments above, it is worth dealing specially with
5551 -- division specially. The only case where integer division can
5552 -- overflow is (largest negative number) / (-1). So we will do
5553 -- an extra range analysis to see if this is possible.
5555 elsif Nkind
(N
) = N_Op_Divide
then
5557 (Left_Opnd
(N
), OK
, Lo
, Hi
, Assume_Valid
=> True);
5559 if OK
and then Lo
> Expr_Value
(Type_Low_Bound
(Typ
)) then
5560 Do_Ovflow_Check
:= False;
5564 (Right_Opnd
(N
), OK
, Lo
, Hi
, Assume_Valid
=> True);
5566 if OK
and then (Lo
> Uint_Minus_1
5570 Do_Ovflow_Check
:= False;
5575 -- If no overflow check required, we are done
5577 if not Do_Ovflow_Check
then
5578 if Debug_Flag_CC
then
5579 w
("No overflow check required");
5587 -- If not in optimizing mode, set flag and we are done. We are also done
5588 -- (and just set the flag) if the type is not a discrete type, since it
5589 -- is not worth the effort to eliminate checks for other than discrete
5590 -- types. In addition, we take this same path if we have stored the
5591 -- maximum number of checks possible already (a very unlikely situation,
5592 -- but we do not want to blow up).
5594 if Optimization_Level
= 0
5595 or else not Is_Discrete_Type
(Etype
(N
))
5596 or else Num_Saved_Checks
= Saved_Checks
'Last
5598 Activate_Overflow_Check
(N
);
5600 if Debug_Flag_CC
then
5601 w
("Optimization off");
5607 -- Otherwise evaluate and check the expression
5612 Target_Type
=> Empty
,
5618 if Debug_Flag_CC
then
5619 w
("Called Find_Check");
5623 w
(" Check_Num = ", Chk
);
5624 w
(" Ent = ", Int
(Ent
));
5625 Write_Str
(" Ofs = ");
5630 -- If check is not of form to optimize, then set flag and we are done
5633 Activate_Overflow_Check
(N
);
5637 -- If check is already performed, then return without setting flag
5640 if Debug_Flag_CC
then
5641 w
("Check suppressed!");
5647 -- Here we will make a new entry for the new check
5649 Activate_Overflow_Check
(N
);
5650 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
5651 Saved_Checks
(Num_Saved_Checks
) :=
5656 Target_Type
=> Empty
);
5658 if Debug_Flag_CC
then
5659 w
("Make new entry, check number = ", Num_Saved_Checks
);
5660 w
(" Entity = ", Int
(Ent
));
5661 Write_Str
(" Offset = ");
5663 w
(" Check_Type = O");
5664 w
(" Target_Type = Empty");
5667 -- If we get an exception, then something went wrong, probably because of
5668 -- an error in the structure of the tree due to an incorrect program. Or
5669 -- it may be a bug in the optimization circuit. In either case the safest
5670 -- thing is simply to set the check flag unconditionally.
5674 Activate_Overflow_Check
(N
);
5676 if Debug_Flag_CC
then
5677 w
(" exception occurred, overflow flag set");
5681 end Enable_Overflow_Check
;
5683 ------------------------
5684 -- Enable_Range_Check --
5685 ------------------------
5687 procedure Enable_Range_Check
(N
: Node_Id
) is
5696 -- Return if unchecked type conversion with range check killed. In this
5697 -- case we never set the flag (that's what Kill_Range_Check is about).
5699 if Nkind
(N
) = N_Unchecked_Type_Conversion
5700 and then Kill_Range_Check
(N
)
5705 -- Do not set range check flag if parent is assignment statement or
5706 -- object declaration with Suppress_Assignment_Checks flag set
5708 if Nkind_In
(Parent
(N
), N_Assignment_Statement
, N_Object_Declaration
)
5709 and then Suppress_Assignment_Checks
(Parent
(N
))
5714 -- Check for various cases where we should suppress the range check
5716 -- No check if range checks suppressed for type of node
5718 if Present
(Etype
(N
)) and then Range_Checks_Suppressed
(Etype
(N
)) then
5721 -- No check if node is an entity name, and range checks are suppressed
5722 -- for this entity, or for the type of this entity.
5724 elsif Is_Entity_Name
(N
)
5725 and then (Range_Checks_Suppressed
(Entity
(N
))
5726 or else Range_Checks_Suppressed
(Etype
(Entity
(N
))))
5730 -- No checks if index of array, and index checks are suppressed for
5731 -- the array object or the type of the array.
5733 elsif Nkind
(Parent
(N
)) = N_Indexed_Component
then
5735 Pref
: constant Node_Id
:= Prefix
(Parent
(N
));
5737 if Is_Entity_Name
(Pref
)
5738 and then Index_Checks_Suppressed
(Entity
(Pref
))
5741 elsif Index_Checks_Suppressed
(Etype
(Pref
)) then
5747 -- Debug trace output
5749 if Debug_Flag_CC
then
5750 w
("Enable_Range_Check for node ", Int
(N
));
5751 Write_Str
(" Source location = ");
5756 -- If not in optimizing mode, set flag and we are done. We are also done
5757 -- (and just set the flag) if the type is not a discrete type, since it
5758 -- is not worth the effort to eliminate checks for other than discrete
5759 -- types. In addition, we take this same path if we have stored the
5760 -- maximum number of checks possible already (a very unlikely situation,
5761 -- but we do not want to blow up).
5763 if Optimization_Level
= 0
5764 or else No
(Etype
(N
))
5765 or else not Is_Discrete_Type
(Etype
(N
))
5766 or else Num_Saved_Checks
= Saved_Checks
'Last
5768 Activate_Range_Check
(N
);
5770 if Debug_Flag_CC
then
5771 w
("Optimization off");
5777 -- Otherwise find out the target type
5781 -- For assignment, use left side subtype
5783 if Nkind
(P
) = N_Assignment_Statement
5784 and then Expression
(P
) = N
5786 Ttyp
:= Etype
(Name
(P
));
5788 -- For indexed component, use subscript subtype
5790 elsif Nkind
(P
) = N_Indexed_Component
then
5797 Atyp
:= Etype
(Prefix
(P
));
5799 if Is_Access_Type
(Atyp
) then
5800 Atyp
:= Designated_Type
(Atyp
);
5802 -- If the prefix is an access to an unconstrained array,
5803 -- perform check unconditionally: it depends on the bounds of
5804 -- an object and we cannot currently recognize whether the test
5805 -- may be redundant.
5807 if not Is_Constrained
(Atyp
) then
5808 Activate_Range_Check
(N
);
5812 -- Ditto if prefix is simply an unconstrained array. We used
5813 -- to think this case was OK, if the prefix was not an explicit
5814 -- dereference, but we have now seen a case where this is not
5815 -- true, so it is safer to just suppress the optimization in this
5816 -- case. The back end is getting better at eliminating redundant
5817 -- checks in any case, so the loss won't be important.
5819 elsif Is_Array_Type
(Atyp
)
5820 and then not Is_Constrained
(Atyp
)
5822 Activate_Range_Check
(N
);
5826 Indx
:= First_Index
(Atyp
);
5827 Subs
:= First
(Expressions
(P
));
5830 Ttyp
:= Etype
(Indx
);
5839 -- For now, ignore all other cases, they are not so interesting
5842 if Debug_Flag_CC
then
5843 w
(" target type not found, flag set");
5846 Activate_Range_Check
(N
);
5850 -- Evaluate and check the expression
5855 Target_Type
=> Ttyp
,
5861 if Debug_Flag_CC
then
5862 w
("Called Find_Check");
5863 w
("Target_Typ = ", Int
(Ttyp
));
5867 w
(" Check_Num = ", Chk
);
5868 w
(" Ent = ", Int
(Ent
));
5869 Write_Str
(" Ofs = ");
5874 -- If check is not of form to optimize, then set flag and we are done
5877 if Debug_Flag_CC
then
5878 w
(" expression not of optimizable type, flag set");
5881 Activate_Range_Check
(N
);
5885 -- If check is already performed, then return without setting flag
5888 if Debug_Flag_CC
then
5889 w
("Check suppressed!");
5895 -- Here we will make a new entry for the new check
5897 Activate_Range_Check
(N
);
5898 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
5899 Saved_Checks
(Num_Saved_Checks
) :=
5904 Target_Type
=> Ttyp
);
5906 if Debug_Flag_CC
then
5907 w
("Make new entry, check number = ", Num_Saved_Checks
);
5908 w
(" Entity = ", Int
(Ent
));
5909 Write_Str
(" Offset = ");
5911 w
(" Check_Type = R");
5912 w
(" Target_Type = ", Int
(Ttyp
));
5913 pg
(Union_Id
(Ttyp
));
5916 -- If we get an exception, then something went wrong, probably because of
5917 -- an error in the structure of the tree due to an incorrect program. Or
5918 -- it may be a bug in the optimization circuit. In either case the safest
5919 -- thing is simply to set the check flag unconditionally.
5923 Activate_Range_Check
(N
);
5925 if Debug_Flag_CC
then
5926 w
(" exception occurred, range flag set");
5930 end Enable_Range_Check
;
5936 procedure Ensure_Valid
5938 Holes_OK
: Boolean := False;
5939 Related_Id
: Entity_Id
:= Empty
;
5940 Is_Low_Bound
: Boolean := False;
5941 Is_High_Bound
: Boolean := False)
5943 Typ
: constant Entity_Id
:= Etype
(Expr
);
5946 -- Ignore call if we are not doing any validity checking
5948 if not Validity_Checks_On
then
5951 -- Ignore call if range or validity checks suppressed on entity or type
5953 elsif Range_Or_Validity_Checks_Suppressed
(Expr
) then
5956 -- No check required if expression is from the expander, we assume the
5957 -- expander will generate whatever checks are needed. Note that this is
5958 -- not just an optimization, it avoids infinite recursions.
5960 -- Unchecked conversions must be checked, unless they are initialized
5961 -- scalar values, as in a component assignment in an init proc.
5963 -- In addition, we force a check if Force_Validity_Checks is set
5965 elsif not Comes_From_Source
(Expr
)
5967 (Nkind
(Expr
) = N_Identifier
5968 and then Present
(Renamed_Object
(Entity
(Expr
)))
5969 and then Comes_From_Source
(Renamed_Object
(Entity
(Expr
))))
5970 and then not Force_Validity_Checks
5971 and then (Nkind
(Expr
) /= N_Unchecked_Type_Conversion
5972 or else Kill_Range_Check
(Expr
))
5976 -- No check required if expression is known to have valid value
5978 elsif Expr_Known_Valid
(Expr
) then
5981 -- No check needed within a generated predicate function. Validity
5982 -- of input value will have been checked earlier.
5984 elsif Ekind
(Current_Scope
) = E_Function
5985 and then Is_Predicate_Function
(Current_Scope
)
5989 -- Ignore case of enumeration with holes where the flag is set not to
5990 -- worry about holes, since no special validity check is needed
5992 elsif Is_Enumeration_Type
(Typ
)
5993 and then Has_Non_Standard_Rep
(Typ
)
5998 -- No check required on the left-hand side of an assignment
6000 elsif Nkind
(Parent
(Expr
)) = N_Assignment_Statement
6001 and then Expr
= Name
(Parent
(Expr
))
6005 -- No check on a universal real constant. The context will eventually
6006 -- convert it to a machine number for some target type, or report an
6009 elsif Nkind
(Expr
) = N_Real_Literal
6010 and then Etype
(Expr
) = Universal_Real
6014 -- If the expression denotes a component of a packed boolean array,
6015 -- no possible check applies. We ignore the old ACATS chestnuts that
6016 -- involve Boolean range True..True.
6018 -- Note: validity checks are generated for expressions that yield a
6019 -- scalar type, when it is possible to create a value that is outside of
6020 -- the type. If this is a one-bit boolean no such value exists. This is
6021 -- an optimization, and it also prevents compiler blowing up during the
6022 -- elaboration of improperly expanded packed array references.
6024 elsif Nkind
(Expr
) = N_Indexed_Component
6025 and then Is_Bit_Packed_Array
(Etype
(Prefix
(Expr
)))
6026 and then Root_Type
(Etype
(Expr
)) = Standard_Boolean
6030 -- For an expression with actions, we want to insert the validity check
6031 -- on the final Expression.
6033 elsif Nkind
(Expr
) = N_Expression_With_Actions
then
6034 Ensure_Valid
(Expression
(Expr
));
6037 -- An annoying special case. If this is an out parameter of a scalar
6038 -- type, then the value is not going to be accessed, therefore it is
6039 -- inappropriate to do any validity check at the call site.
6042 -- Only need to worry about scalar types
6044 if Is_Scalar_Type
(Typ
) then
6054 -- Find actual argument (which may be a parameter association)
6055 -- and the parent of the actual argument (the call statement)
6060 if Nkind
(P
) = N_Parameter_Association
then
6065 -- Only need to worry if we are argument of a procedure call
6066 -- since functions don't have out parameters. If this is an
6067 -- indirect or dispatching call, get signature from the
6070 if Nkind
(P
) = N_Procedure_Call_Statement
then
6071 L
:= Parameter_Associations
(P
);
6073 if Is_Entity_Name
(Name
(P
)) then
6074 E
:= Entity
(Name
(P
));
6076 pragma Assert
(Nkind
(Name
(P
)) = N_Explicit_Dereference
);
6077 E
:= Etype
(Name
(P
));
6080 -- Only need to worry if there are indeed actuals, and if
6081 -- this could be a procedure call, otherwise we cannot get a
6082 -- match (either we are not an argument, or the mode of the
6083 -- formal is not OUT). This test also filters out the
6086 if Is_Non_Empty_List
(L
) and then Is_Subprogram
(E
) then
6088 -- This is the loop through parameters, looking for an
6089 -- OUT parameter for which we are the argument.
6091 F
:= First_Formal
(E
);
6093 while Present
(F
) loop
6094 if Ekind
(F
) = E_Out_Parameter
and then A
= N
then
6107 -- If this is a boolean expression, only its elementary operands need
6108 -- checking: if they are valid, a boolean or short-circuit operation
6109 -- with them will be valid as well.
6111 if Base_Type
(Typ
) = Standard_Boolean
6113 (Nkind
(Expr
) in N_Op
or else Nkind
(Expr
) in N_Short_Circuit
)
6118 -- If we fall through, a validity check is required
6120 Insert_Valid_Check
(Expr
, Related_Id
, Is_Low_Bound
, Is_High_Bound
);
6122 if Is_Entity_Name
(Expr
)
6123 and then Safe_To_Capture_Value
(Expr
, Entity
(Expr
))
6125 Set_Is_Known_Valid
(Entity
(Expr
));
6129 ----------------------
6130 -- Expr_Known_Valid --
6131 ----------------------
6133 function Expr_Known_Valid
(Expr
: Node_Id
) return Boolean is
6134 Typ
: constant Entity_Id
:= Etype
(Expr
);
6137 -- Non-scalar types are always considered valid, since they never give
6138 -- rise to the issues of erroneous or bounded error behavior that are
6139 -- the concern. In formal reference manual terms the notion of validity
6140 -- only applies to scalar types. Note that even when packed arrays are
6141 -- represented using modular types, they are still arrays semantically,
6142 -- so they are also always valid (in particular, the unused bits can be
6143 -- random rubbish without affecting the validity of the array value).
6145 if not Is_Scalar_Type
(Typ
) or else Is_Packed_Array_Impl_Type
(Typ
) then
6148 -- If no validity checking, then everything is considered valid
6150 elsif not Validity_Checks_On
then
6153 -- Floating-point types are considered valid unless floating-point
6154 -- validity checks have been specifically turned on.
6156 elsif Is_Floating_Point_Type
(Typ
)
6157 and then not Validity_Check_Floating_Point
6161 -- If the expression is the value of an object that is known to be
6162 -- valid, then clearly the expression value itself is valid.
6164 elsif Is_Entity_Name
(Expr
)
6165 and then Is_Known_Valid
(Entity
(Expr
))
6167 -- Exclude volatile variables
6169 and then not Treat_As_Volatile
(Entity
(Expr
))
6173 -- References to discriminants are always considered valid. The value
6174 -- of a discriminant gets checked when the object is built. Within the
6175 -- record, we consider it valid, and it is important to do so, since
6176 -- otherwise we can try to generate bogus validity checks which
6177 -- reference discriminants out of scope. Discriminants of concurrent
6178 -- types are excluded for the same reason.
6180 elsif Is_Entity_Name
(Expr
)
6181 and then Denotes_Discriminant
(Expr
, Check_Concurrent
=> True)
6185 -- If the type is one for which all values are known valid, then we are
6186 -- sure that the value is valid except in the slightly odd case where
6187 -- the expression is a reference to a variable whose size has been
6188 -- explicitly set to a value greater than the object size.
6190 elsif Is_Known_Valid
(Typ
) then
6191 if Is_Entity_Name
(Expr
)
6192 and then Ekind
(Entity
(Expr
)) = E_Variable
6193 and then Esize
(Entity
(Expr
)) > Esize
(Typ
)
6200 -- Integer and character literals always have valid values, where
6201 -- appropriate these will be range checked in any case.
6203 elsif Nkind_In
(Expr
, N_Integer_Literal
, N_Character_Literal
) then
6206 -- If we have a type conversion or a qualification of a known valid
6207 -- value, then the result will always be valid.
6209 elsif Nkind_In
(Expr
, N_Type_Conversion
, N_Qualified_Expression
) then
6210 return Expr_Known_Valid
(Expression
(Expr
));
6212 -- Case of expression is a non-floating-point operator. In this case we
6213 -- can assume the result is valid the generated code for the operator
6214 -- will include whatever checks are needed (e.g. range checks) to ensure
6215 -- validity. This assumption does not hold for the floating-point case,
6216 -- since floating-point operators can generate Infinite or NaN results
6217 -- which are considered invalid.
6219 -- Historical note: in older versions, the exemption of floating-point
6220 -- types from this assumption was done only in cases where the parent
6221 -- was an assignment, function call or parameter association. Presumably
6222 -- the idea was that in other contexts, the result would be checked
6223 -- elsewhere, but this list of cases was missing tests (at least the
6224 -- N_Object_Declaration case, as shown by a reported missing validity
6225 -- check), and it is not clear why function calls but not procedure
6226 -- calls were tested for. It really seems more accurate and much
6227 -- safer to recognize that expressions which are the result of a
6228 -- floating-point operator can never be assumed to be valid.
6230 elsif Nkind
(Expr
) in N_Op
and then not Is_Floating_Point_Type
(Typ
) then
6233 -- The result of a membership test is always valid, since it is true or
6234 -- false, there are no other possibilities.
6236 elsif Nkind
(Expr
) in N_Membership_Test
then
6239 -- For all other cases, we do not know the expression is valid
6244 end Expr_Known_Valid
;
6250 procedure Find_Check
6252 Check_Type
: Character;
6253 Target_Type
: Entity_Id
;
6254 Entry_OK
: out Boolean;
6255 Check_Num
: out Nat
;
6256 Ent
: out Entity_Id
;
6259 function Within_Range_Of
6260 (Target_Type
: Entity_Id
;
6261 Check_Type
: Entity_Id
) return Boolean;
6262 -- Given a requirement for checking a range against Target_Type, and
6263 -- and a range Check_Type against which a check has already been made,
6264 -- determines if the check against check type is sufficient to ensure
6265 -- that no check against Target_Type is required.
6267 ---------------------
6268 -- Within_Range_Of --
6269 ---------------------
6271 function Within_Range_Of
6272 (Target_Type
: Entity_Id
;
6273 Check_Type
: Entity_Id
) return Boolean
6276 if Target_Type
= Check_Type
then
6281 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Type
);
6282 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Type
);
6283 Clo
: constant Node_Id
:= Type_Low_Bound
(Check_Type
);
6284 Chi
: constant Node_Id
:= Type_High_Bound
(Check_Type
);
6288 or else (Compile_Time_Known_Value
(Tlo
)
6290 Compile_Time_Known_Value
(Clo
)
6292 Expr_Value
(Clo
) >= Expr_Value
(Tlo
)))
6295 or else (Compile_Time_Known_Value
(Thi
)
6297 Compile_Time_Known_Value
(Chi
)
6299 Expr_Value
(Chi
) <= Expr_Value
(Clo
)))
6307 end Within_Range_Of
;
6309 -- Start of processing for Find_Check
6312 -- Establish default, in case no entry is found
6316 -- Case of expression is simple entity reference
6318 if Is_Entity_Name
(Expr
) then
6319 Ent
:= Entity
(Expr
);
6322 -- Case of expression is entity + known constant
6324 elsif Nkind
(Expr
) = N_Op_Add
6325 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
6326 and then Is_Entity_Name
(Left_Opnd
(Expr
))
6328 Ent
:= Entity
(Left_Opnd
(Expr
));
6329 Ofs
:= Expr_Value
(Right_Opnd
(Expr
));
6331 -- Case of expression is entity - known constant
6333 elsif Nkind
(Expr
) = N_Op_Subtract
6334 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
6335 and then Is_Entity_Name
(Left_Opnd
(Expr
))
6337 Ent
:= Entity
(Left_Opnd
(Expr
));
6338 Ofs
:= UI_Negate
(Expr_Value
(Right_Opnd
(Expr
)));
6340 -- Any other expression is not of the right form
6349 -- Come here with expression of appropriate form, check if entity is an
6350 -- appropriate one for our purposes.
6352 if (Ekind
(Ent
) = E_Variable
6353 or else Is_Constant_Object
(Ent
))
6354 and then not Is_Library_Level_Entity
(Ent
)
6362 -- See if there is matching check already
6364 for J
in reverse 1 .. Num_Saved_Checks
loop
6366 SC
: Saved_Check
renames Saved_Checks
(J
);
6368 if SC
.Killed
= False
6369 and then SC
.Entity
= Ent
6370 and then SC
.Offset
= Ofs
6371 and then SC
.Check_Type
= Check_Type
6372 and then Within_Range_Of
(Target_Type
, SC
.Target_Type
)
6380 -- If we fall through entry was not found
6385 ---------------------------------
6386 -- Generate_Discriminant_Check --
6387 ---------------------------------
6389 -- Note: the code for this procedure is derived from the
6390 -- Emit_Discriminant_Check Routine in trans.c.
6392 procedure Generate_Discriminant_Check
(N
: Node_Id
) is
6393 Loc
: constant Source_Ptr
:= Sloc
(N
);
6394 Pref
: constant Node_Id
:= Prefix
(N
);
6395 Sel
: constant Node_Id
:= Selector_Name
(N
);
6397 Orig_Comp
: constant Entity_Id
:=
6398 Original_Record_Component
(Entity
(Sel
));
6399 -- The original component to be checked
6401 Discr_Fct
: constant Entity_Id
:=
6402 Discriminant_Checking_Func
(Orig_Comp
);
6403 -- The discriminant checking function
6406 -- One discriminant to be checked in the type
6408 Real_Discr
: Entity_Id
;
6409 -- Actual discriminant in the call
6411 Pref_Type
: Entity_Id
;
6412 -- Type of relevant prefix (ignoring private/access stuff)
6415 -- List of arguments for function call
6418 -- Keep track of the formal corresponding to the actual we build for
6419 -- each discriminant, in order to be able to perform the necessary type
6423 -- Selected component reference for checking function argument
6426 Pref_Type
:= Etype
(Pref
);
6428 -- Force evaluation of the prefix, so that it does not get evaluated
6429 -- twice (once for the check, once for the actual reference). Such a
6430 -- double evaluation is always a potential source of inefficiency, and
6431 -- is functionally incorrect in the volatile case, or when the prefix
6432 -- may have side effects. A nonvolatile entity or a component of a
6433 -- nonvolatile entity requires no evaluation.
6435 if Is_Entity_Name
(Pref
) then
6436 if Treat_As_Volatile
(Entity
(Pref
)) then
6437 Force_Evaluation
(Pref
, Name_Req
=> True);
6440 elsif Treat_As_Volatile
(Etype
(Pref
)) then
6441 Force_Evaluation
(Pref
, Name_Req
=> True);
6443 elsif Nkind
(Pref
) = N_Selected_Component
6444 and then Is_Entity_Name
(Prefix
(Pref
))
6449 Force_Evaluation
(Pref
, Name_Req
=> True);
6452 -- For a tagged type, use the scope of the original component to
6453 -- obtain the type, because ???
6455 if Is_Tagged_Type
(Scope
(Orig_Comp
)) then
6456 Pref_Type
:= Scope
(Orig_Comp
);
6458 -- For an untagged derived type, use the discriminants of the parent
6459 -- which have been renamed in the derivation, possibly by a one-to-many
6460 -- discriminant constraint. For untagged type, initially get the Etype
6464 if Is_Derived_Type
(Pref_Type
)
6465 and then Number_Discriminants
(Pref_Type
) /=
6466 Number_Discriminants
(Etype
(Base_Type
(Pref_Type
)))
6468 Pref_Type
:= Etype
(Base_Type
(Pref_Type
));
6472 -- We definitely should have a checking function, This routine should
6473 -- not be called if no discriminant checking function is present.
6475 pragma Assert
(Present
(Discr_Fct
));
6477 -- Create the list of the actual parameters for the call. This list
6478 -- is the list of the discriminant fields of the record expression to
6479 -- be discriminant checked.
6482 Formal
:= First_Formal
(Discr_Fct
);
6483 Discr
:= First_Discriminant
(Pref_Type
);
6484 while Present
(Discr
) loop
6486 -- If we have a corresponding discriminant field, and a parent
6487 -- subtype is present, then we want to use the corresponding
6488 -- discriminant since this is the one with the useful value.
6490 if Present
(Corresponding_Discriminant
(Discr
))
6491 and then Ekind
(Pref_Type
) = E_Record_Type
6492 and then Present
(Parent_Subtype
(Pref_Type
))
6494 Real_Discr
:= Corresponding_Discriminant
(Discr
);
6496 Real_Discr
:= Discr
;
6499 -- Construct the reference to the discriminant
6502 Make_Selected_Component
(Loc
,
6504 Unchecked_Convert_To
(Pref_Type
,
6505 Duplicate_Subexpr
(Pref
)),
6506 Selector_Name
=> New_Occurrence_Of
(Real_Discr
, Loc
));
6508 -- Manually analyze and resolve this selected component. We really
6509 -- want it just as it appears above, and do not want the expander
6510 -- playing discriminal games etc with this reference. Then we append
6511 -- the argument to the list we are gathering.
6513 Set_Etype
(Scomp
, Etype
(Real_Discr
));
6514 Set_Analyzed
(Scomp
, True);
6515 Append_To
(Args
, Convert_To
(Etype
(Formal
), Scomp
));
6517 Next_Formal_With_Extras
(Formal
);
6518 Next_Discriminant
(Discr
);
6521 -- Now build and insert the call
6524 Make_Raise_Constraint_Error
(Loc
,
6526 Make_Function_Call
(Loc
,
6527 Name
=> New_Occurrence_Of
(Discr_Fct
, Loc
),
6528 Parameter_Associations
=> Args
),
6529 Reason
=> CE_Discriminant_Check_Failed
));
6530 end Generate_Discriminant_Check
;
6532 ---------------------------
6533 -- Generate_Index_Checks --
6534 ---------------------------
6536 procedure Generate_Index_Checks
(N
: Node_Id
) is
6538 function Entity_Of_Prefix
return Entity_Id
;
6539 -- Returns the entity of the prefix of N (or Empty if not found)
6541 ----------------------
6542 -- Entity_Of_Prefix --
6543 ----------------------
6545 function Entity_Of_Prefix
return Entity_Id
is
6550 while not Is_Entity_Name
(P
) loop
6551 if not Nkind_In
(P
, N_Selected_Component
,
6552 N_Indexed_Component
)
6561 end Entity_Of_Prefix
;
6565 Loc
: constant Source_Ptr
:= Sloc
(N
);
6566 A
: constant Node_Id
:= Prefix
(N
);
6567 A_Ent
: constant Entity_Id
:= Entity_Of_Prefix
;
6570 -- Start of processing for Generate_Index_Checks
6573 -- Ignore call if the prefix is not an array since we have a serious
6574 -- error in the sources. Ignore it also if index checks are suppressed
6575 -- for array object or type.
6577 if not Is_Array_Type
(Etype
(A
))
6578 or else (Present
(A_Ent
) and then Index_Checks_Suppressed
(A_Ent
))
6579 or else Index_Checks_Suppressed
(Etype
(A
))
6583 -- The indexed component we are dealing with contains 'Loop_Entry in its
6584 -- prefix. This case arises when analysis has determined that constructs
6587 -- Prefix'Loop_Entry (Expr)
6588 -- Prefix'Loop_Entry (Expr1, Expr2, ... ExprN)
6590 -- require rewriting for error detection purposes. A side effect of this
6591 -- action is the generation of index checks that mention 'Loop_Entry.
6592 -- Delay the generation of the check until 'Loop_Entry has been properly
6593 -- expanded. This is done in Expand_Loop_Entry_Attributes.
6595 elsif Nkind
(Prefix
(N
)) = N_Attribute_Reference
6596 and then Attribute_Name
(Prefix
(N
)) = Name_Loop_Entry
6601 -- Generate a raise of constraint error with the appropriate reason and
6602 -- a condition of the form:
6604 -- Base_Type (Sub) not in Array'Range (Subscript)
6606 -- Note that the reason we generate the conversion to the base type here
6607 -- is that we definitely want the range check to take place, even if it
6608 -- looks like the subtype is OK. Optimization considerations that allow
6609 -- us to omit the check have already been taken into account in the
6610 -- setting of the Do_Range_Check flag earlier on.
6612 Sub
:= First
(Expressions
(N
));
6614 -- Handle string literals
6616 if Ekind
(Etype
(A
)) = E_String_Literal_Subtype
then
6617 if Do_Range_Check
(Sub
) then
6618 Set_Do_Range_Check
(Sub
, False);
6620 -- For string literals we obtain the bounds of the string from the
6621 -- associated subtype.
6624 Make_Raise_Constraint_Error
(Loc
,
6628 Convert_To
(Base_Type
(Etype
(Sub
)),
6629 Duplicate_Subexpr_Move_Checks
(Sub
)),
6631 Make_Attribute_Reference
(Loc
,
6632 Prefix
=> New_Occurrence_Of
(Etype
(A
), Loc
),
6633 Attribute_Name
=> Name_Range
)),
6634 Reason
=> CE_Index_Check_Failed
));
6641 A_Idx
: Node_Id
:= Empty
;
6648 A_Idx
:= First_Index
(Etype
(A
));
6650 while Present
(Sub
) loop
6651 if Do_Range_Check
(Sub
) then
6652 Set_Do_Range_Check
(Sub
, False);
6654 -- Force evaluation except for the case of a simple name of
6655 -- a nonvolatile entity.
6657 if not Is_Entity_Name
(Sub
)
6658 or else Treat_As_Volatile
(Entity
(Sub
))
6660 Force_Evaluation
(Sub
);
6663 if Nkind
(A_Idx
) = N_Range
then
6666 elsif Nkind
(A_Idx
) = N_Identifier
6667 or else Nkind
(A_Idx
) = N_Expanded_Name
6669 A_Range
:= Scalar_Range
(Entity
(A_Idx
));
6671 else pragma Assert
(Nkind
(A_Idx
) = N_Subtype_Indication
);
6672 A_Range
:= Range_Expression
(Constraint
(A_Idx
));
6675 -- For array objects with constant bounds we can generate
6676 -- the index check using the bounds of the type of the index
6679 and then Ekind
(A_Ent
) = E_Variable
6680 and then Is_Constant_Bound
(Low_Bound
(A_Range
))
6681 and then Is_Constant_Bound
(High_Bound
(A_Range
))
6684 Make_Attribute_Reference
(Loc
,
6686 New_Occurrence_Of
(Etype
(A_Idx
), Loc
),
6687 Attribute_Name
=> Name_Range
);
6689 -- For arrays with non-constant bounds we cannot generate
6690 -- the index check using the bounds of the type of the index
6691 -- since it may reference discriminants of some enclosing
6692 -- type. We obtain the bounds directly from the prefix
6699 Num
:= New_List
(Make_Integer_Literal
(Loc
, Ind
));
6703 Make_Attribute_Reference
(Loc
,
6705 Duplicate_Subexpr_Move_Checks
(A
, Name_Req
=> True),
6706 Attribute_Name
=> Name_Range
,
6707 Expressions
=> Num
);
6711 Make_Raise_Constraint_Error
(Loc
,
6715 Convert_To
(Base_Type
(Etype
(Sub
)),
6716 Duplicate_Subexpr_Move_Checks
(Sub
)),
6717 Right_Opnd
=> Range_N
),
6718 Reason
=> CE_Index_Check_Failed
));
6721 A_Idx
:= Next_Index
(A_Idx
);
6727 end Generate_Index_Checks
;
6729 --------------------------
6730 -- Generate_Range_Check --
6731 --------------------------
6733 procedure Generate_Range_Check
6735 Target_Type
: Entity_Id
;
6736 Reason
: RT_Exception_Code
)
6738 Loc
: constant Source_Ptr
:= Sloc
(N
);
6739 Source_Type
: constant Entity_Id
:= Etype
(N
);
6740 Source_Base_Type
: constant Entity_Id
:= Base_Type
(Source_Type
);
6741 Target_Base_Type
: constant Entity_Id
:= Base_Type
(Target_Type
);
6743 procedure Convert_And_Check_Range
;
6744 -- Convert the conversion operand to the target base type and save in
6745 -- a temporary. Then check the converted value against the range of the
6748 -----------------------------
6749 -- Convert_And_Check_Range --
6750 -----------------------------
6752 procedure Convert_And_Check_Range
is
6753 Tnn
: constant Entity_Id
:= Make_Temporary
(Loc
, 'T', N
);
6756 -- We make a temporary to hold the value of the converted value
6757 -- (converted to the base type), and then do the test against this
6758 -- temporary. The conversion itself is replaced by an occurrence of
6759 -- Tnn and followed by the explicit range check. Note that checks
6760 -- are suppressed for this code, since we don't want a recursive
6761 -- range check popping up.
6763 -- Tnn : constant Target_Base_Type := Target_Base_Type (N);
6764 -- [constraint_error when Tnn not in Target_Type]
6766 Insert_Actions
(N
, New_List
(
6767 Make_Object_Declaration
(Loc
,
6768 Defining_Identifier
=> Tnn
,
6769 Object_Definition
=> New_Occurrence_Of
(Target_Base_Type
, Loc
),
6770 Constant_Present
=> True,
6772 Make_Type_Conversion
(Loc
,
6773 Subtype_Mark
=> New_Occurrence_Of
(Target_Base_Type
, Loc
),
6774 Expression
=> Duplicate_Subexpr
(N
))),
6776 Make_Raise_Constraint_Error
(Loc
,
6779 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
6780 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
6782 Suppress
=> All_Checks
);
6784 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
6786 -- Set the type of N, because the declaration for Tnn might not
6787 -- be analyzed yet, as is the case if N appears within a record
6788 -- declaration, as a discriminant constraint or expression.
6790 Set_Etype
(N
, Target_Base_Type
);
6791 end Convert_And_Check_Range
;
6793 -- Start of processing for Generate_Range_Check
6796 -- First special case, if the source type is already within the range
6797 -- of the target type, then no check is needed (probably we should have
6798 -- stopped Do_Range_Check from being set in the first place, but better
6799 -- late than never in preventing junk code and junk flag settings.
6801 if In_Subrange_Of
(Source_Type
, Target_Type
)
6803 -- We do NOT apply this if the source node is a literal, since in this
6804 -- case the literal has already been labeled as having the subtype of
6808 (Nkind_In
(N
, N_Integer_Literal
, N_Real_Literal
, N_Character_Literal
)
6811 and then Ekind
(Entity
(N
)) = E_Enumeration_Literal
))
6813 Set_Do_Range_Check
(N
, False);
6817 -- Here a check is needed. If the expander is not active, or if we are
6818 -- in GNATProve mode, then simply set the Do_Range_Check flag and we
6819 -- are done. In both these cases, we just want to see the range check
6820 -- flag set, we do not want to generate the explicit range check code.
6822 if GNATprove_Mode
or else not Expander_Active
then
6823 Set_Do_Range_Check
(N
, True);
6827 -- Here we will generate an explicit range check, so we don't want to
6828 -- set the Do_Range check flag, since the range check is taken care of
6829 -- by the code we will generate.
6831 Set_Do_Range_Check
(N
, False);
6833 -- Force evaluation of the node, so that it does not get evaluated twice
6834 -- (once for the check, once for the actual reference). Such a double
6835 -- evaluation is always a potential source of inefficiency, and is
6836 -- functionally incorrect in the volatile case.
6838 -- We skip the evaluation of attribute references because, after these
6839 -- runtime checks are generated, the expander may need to rewrite this
6840 -- node (for example, see Attribute_Max_Size_In_Storage_Elements in
6841 -- Expand_N_Attribute_Reference).
6843 if Nkind
(N
) /= N_Attribute_Reference
6844 and then (not Is_Entity_Name
(N
)
6845 or else Treat_As_Volatile
(Entity
(N
)))
6847 Force_Evaluation
(N
, Mode
=> Strict
);
6850 -- The easiest case is when Source_Base_Type and Target_Base_Type are
6851 -- the same since in this case we can simply do a direct check of the
6852 -- value of N against the bounds of Target_Type.
6854 -- [constraint_error when N not in Target_Type]
6856 -- Note: this is by far the most common case, for example all cases of
6857 -- checks on the RHS of assignments are in this category, but not all
6858 -- cases are like this. Notably conversions can involve two types.
6860 if Source_Base_Type
= Target_Base_Type
then
6862 -- Insert the explicit range check. Note that we suppress checks for
6863 -- this code, since we don't want a recursive range check popping up.
6866 Make_Raise_Constraint_Error
(Loc
,
6869 Left_Opnd
=> Duplicate_Subexpr
(N
),
6870 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
6872 Suppress
=> All_Checks
);
6874 -- Next test for the case where the target type is within the bounds
6875 -- of the base type of the source type, since in this case we can
6876 -- simply convert these bounds to the base type of T to do the test.
6878 -- [constraint_error when N not in
6879 -- Source_Base_Type (Target_Type'First)
6881 -- Source_Base_Type(Target_Type'Last))]
6883 -- The conversions will always work and need no check
6885 -- Unchecked_Convert_To is used instead of Convert_To to handle the case
6886 -- of converting from an enumeration value to an integer type, such as
6887 -- occurs for the case of generating a range check on Enum'Val(Exp)
6888 -- (which used to be handled by gigi). This is OK, since the conversion
6889 -- itself does not require a check.
6891 elsif In_Subrange_Of
(Target_Type
, Source_Base_Type
) then
6893 -- Insert the explicit range check. Note that we suppress checks for
6894 -- this code, since we don't want a recursive range check popping up.
6896 if Is_Discrete_Type
(Source_Base_Type
)
6898 Is_Discrete_Type
(Target_Base_Type
)
6901 Make_Raise_Constraint_Error
(Loc
,
6904 Left_Opnd
=> Duplicate_Subexpr
(N
),
6909 Unchecked_Convert_To
(Source_Base_Type
,
6910 Make_Attribute_Reference
(Loc
,
6912 New_Occurrence_Of
(Target_Type
, Loc
),
6913 Attribute_Name
=> Name_First
)),
6916 Unchecked_Convert_To
(Source_Base_Type
,
6917 Make_Attribute_Reference
(Loc
,
6919 New_Occurrence_Of
(Target_Type
, Loc
),
6920 Attribute_Name
=> Name_Last
)))),
6922 Suppress
=> All_Checks
);
6924 -- For conversions involving at least one type that is not discrete,
6925 -- first convert to target type and then generate the range check.
6926 -- This avoids problems with values that are close to a bound of the
6927 -- target type that would fail a range check when done in a larger
6928 -- source type before converting but would pass if converted with
6929 -- rounding and then checked (such as in float-to-float conversions).
6932 Convert_And_Check_Range
;
6935 -- Note that at this stage we now that the Target_Base_Type is not in
6936 -- the range of the Source_Base_Type (since even the Target_Type itself
6937 -- is not in this range). It could still be the case that Source_Type is
6938 -- in range of the target base type since we have not checked that case.
6940 -- If that is the case, we can freely convert the source to the target,
6941 -- and then test the target result against the bounds.
6943 elsif In_Subrange_Of
(Source_Type
, Target_Base_Type
) then
6944 Convert_And_Check_Range
;
6946 -- At this stage, we know that we have two scalar types, which are
6947 -- directly convertible, and where neither scalar type has a base
6948 -- range that is in the range of the other scalar type.
6950 -- The only way this can happen is with a signed and unsigned type.
6951 -- So test for these two cases:
6954 -- Case of the source is unsigned and the target is signed
6956 if Is_Unsigned_Type
(Source_Base_Type
)
6957 and then not Is_Unsigned_Type
(Target_Base_Type
)
6959 -- If the source is unsigned and the target is signed, then we
6960 -- know that the source is not shorter than the target (otherwise
6961 -- the source base type would be in the target base type range).
6963 -- In other words, the unsigned type is either the same size as
6964 -- the target, or it is larger. It cannot be smaller.
6967 (Esize
(Source_Base_Type
) >= Esize
(Target_Base_Type
));
6969 -- We only need to check the low bound if the low bound of the
6970 -- target type is non-negative. If the low bound of the target
6971 -- type is negative, then we know that we will fit fine.
6973 -- If the high bound of the target type is negative, then we
6974 -- know we have a constraint error, since we can't possibly
6975 -- have a negative source.
6977 -- With these two checks out of the way, we can do the check
6978 -- using the source type safely
6980 -- This is definitely the most annoying case.
6982 -- [constraint_error
6983 -- when (Target_Type'First >= 0
6985 -- N < Source_Base_Type (Target_Type'First))
6986 -- or else Target_Type'Last < 0
6987 -- or else N > Source_Base_Type (Target_Type'Last)];
6989 -- We turn off all checks since we know that the conversions
6990 -- will work fine, given the guards for negative values.
6993 Make_Raise_Constraint_Error
(Loc
,
6999 Left_Opnd
=> Make_Op_Ge
(Loc
,
7001 Make_Attribute_Reference
(Loc
,
7003 New_Occurrence_Of
(Target_Type
, Loc
),
7004 Attribute_Name
=> Name_First
),
7005 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
7009 Left_Opnd
=> Duplicate_Subexpr
(N
),
7011 Convert_To
(Source_Base_Type
,
7012 Make_Attribute_Reference
(Loc
,
7014 New_Occurrence_Of
(Target_Type
, Loc
),
7015 Attribute_Name
=> Name_First
)))),
7020 Make_Attribute_Reference
(Loc
,
7021 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
7022 Attribute_Name
=> Name_Last
),
7023 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
))),
7027 Left_Opnd
=> Duplicate_Subexpr
(N
),
7029 Convert_To
(Source_Base_Type
,
7030 Make_Attribute_Reference
(Loc
,
7031 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
7032 Attribute_Name
=> Name_Last
)))),
7035 Suppress
=> All_Checks
);
7037 -- Only remaining possibility is that the source is signed and
7038 -- the target is unsigned.
7041 pragma Assert
(not Is_Unsigned_Type
(Source_Base_Type
)
7042 and then Is_Unsigned_Type
(Target_Base_Type
));
7044 -- If the source is signed and the target is unsigned, then we
7045 -- know that the target is not shorter than the source (otherwise
7046 -- the target base type would be in the source base type range).
7048 -- In other words, the unsigned type is either the same size as
7049 -- the target, or it is larger. It cannot be smaller.
7051 -- Clearly we have an error if the source value is negative since
7052 -- no unsigned type can have negative values. If the source type
7053 -- is non-negative, then the check can be done using the target
7056 -- Tnn : constant Target_Base_Type (N) := Target_Type;
7058 -- [constraint_error
7059 -- when N < 0 or else Tnn not in Target_Type];
7061 -- We turn off all checks for the conversion of N to the target
7062 -- base type, since we generate the explicit check to ensure that
7063 -- the value is non-negative
7066 Tnn
: constant Entity_Id
:= Make_Temporary
(Loc
, 'T', N
);
7069 Insert_Actions
(N
, New_List
(
7070 Make_Object_Declaration
(Loc
,
7071 Defining_Identifier
=> Tnn
,
7072 Object_Definition
=>
7073 New_Occurrence_Of
(Target_Base_Type
, Loc
),
7074 Constant_Present
=> True,
7076 Make_Unchecked_Type_Conversion
(Loc
,
7078 New_Occurrence_Of
(Target_Base_Type
, Loc
),
7079 Expression
=> Duplicate_Subexpr
(N
))),
7081 Make_Raise_Constraint_Error
(Loc
,
7086 Left_Opnd
=> Duplicate_Subexpr
(N
),
7087 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
7091 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
7093 New_Occurrence_Of
(Target_Type
, Loc
))),
7096 Suppress
=> All_Checks
);
7098 -- Set the Etype explicitly, because Insert_Actions may have
7099 -- placed the declaration in the freeze list for an enclosing
7100 -- construct, and thus it is not analyzed yet.
7102 Set_Etype
(Tnn
, Target_Base_Type
);
7103 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
7107 end Generate_Range_Check
;
7113 function Get_Check_Id
(N
: Name_Id
) return Check_Id
is
7115 -- For standard check name, we can do a direct computation
7117 if N
in First_Check_Name
.. Last_Check_Name
then
7118 return Check_Id
(N
- (First_Check_Name
- 1));
7120 -- For non-standard names added by pragma Check_Name, search table
7123 for J
in All_Checks
+ 1 .. Check_Names
.Last
loop
7124 if Check_Names
.Table
(J
) = N
then
7130 -- No matching name found
7135 ---------------------
7136 -- Get_Discriminal --
7137 ---------------------
7139 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
is
7140 Loc
: constant Source_Ptr
:= Sloc
(E
);
7145 -- The bound can be a bona fide parameter of a protected operation,
7146 -- rather than a prival encoded as an in-parameter.
7148 if No
(Discriminal_Link
(Entity
(Bound
))) then
7152 -- Climb the scope stack looking for an enclosing protected type. If
7153 -- we run out of scopes, return the bound itself.
7156 while Present
(Sc
) loop
7157 if Sc
= Standard_Standard
then
7159 elsif Ekind
(Sc
) = E_Protected_Type
then
7166 D
:= First_Discriminant
(Sc
);
7167 while Present
(D
) loop
7168 if Chars
(D
) = Chars
(Bound
) then
7169 return New_Occurrence_Of
(Discriminal
(D
), Loc
);
7172 Next_Discriminant
(D
);
7176 end Get_Discriminal
;
7178 ----------------------
7179 -- Get_Range_Checks --
7180 ----------------------
7182 function Get_Range_Checks
7184 Target_Typ
: Entity_Id
;
7185 Source_Typ
: Entity_Id
:= Empty
;
7186 Warn_Node
: Node_Id
:= Empty
) return Check_Result
7190 Selected_Range_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Warn_Node
);
7191 end Get_Range_Checks
;
7197 function Guard_Access
7200 Ck_Node
: Node_Id
) return Node_Id
7203 if Nkind
(Cond
) = N_Or_Else
then
7204 Set_Paren_Count
(Cond
, 1);
7207 if Nkind
(Ck_Node
) = N_Allocator
then
7215 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
7216 Right_Opnd
=> Make_Null
(Loc
)),
7217 Right_Opnd
=> Cond
);
7221 -----------------------------
7222 -- Index_Checks_Suppressed --
7223 -----------------------------
7225 function Index_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
7227 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
7228 return Is_Check_Suppressed
(E
, Index_Check
);
7230 return Scope_Suppress
.Suppress
(Index_Check
);
7232 end Index_Checks_Suppressed
;
7238 procedure Initialize
is
7240 for J
in Determine_Range_Cache_N
'Range loop
7241 Determine_Range_Cache_N
(J
) := Empty
;
7246 for J
in Int
range 1 .. All_Checks
loop
7247 Check_Names
.Append
(Name_Id
(Int
(First_Check_Name
) + J
- 1));
7251 -------------------------
7252 -- Insert_Range_Checks --
7253 -------------------------
7255 procedure Insert_Range_Checks
7256 (Checks
: Check_Result
;
7258 Suppress_Typ
: Entity_Id
;
7259 Static_Sloc
: Source_Ptr
:= No_Location
;
7260 Flag_Node
: Node_Id
:= Empty
;
7261 Do_Before
: Boolean := False)
7263 Checks_On
: constant Boolean :=
7264 not Index_Checks_Suppressed
(Suppress_Typ
)
7266 not Range_Checks_Suppressed
(Suppress_Typ
);
7268 Check_Node
: Node_Id
;
7269 Internal_Flag_Node
: Node_Id
:= Flag_Node
;
7270 Internal_Static_Sloc
: Source_Ptr
:= Static_Sloc
;
7273 -- For now we just return if Checks_On is false, however this should be
7274 -- enhanced to check for an always True value in the condition and to
7275 -- generate a compilation warning???
7277 if not Expander_Active
or not Checks_On
then
7281 if Static_Sloc
= No_Location
then
7282 Internal_Static_Sloc
:= Sloc
(Node
);
7285 if No
(Flag_Node
) then
7286 Internal_Flag_Node
:= Node
;
7289 for J
in 1 .. 2 loop
7290 exit when No
(Checks
(J
));
7292 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
7293 and then Present
(Condition
(Checks
(J
)))
7295 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
7296 Check_Node
:= Checks
(J
);
7297 Mark_Rewrite_Insertion
(Check_Node
);
7300 Insert_Before_And_Analyze
(Node
, Check_Node
);
7302 Insert_After_And_Analyze
(Node
, Check_Node
);
7305 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
7310 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
7311 Reason
=> CE_Range_Check_Failed
);
7312 Mark_Rewrite_Insertion
(Check_Node
);
7315 Insert_Before_And_Analyze
(Node
, Check_Node
);
7317 Insert_After_And_Analyze
(Node
, Check_Node
);
7321 end Insert_Range_Checks
;
7323 ------------------------
7324 -- Insert_Valid_Check --
7325 ------------------------
7327 procedure Insert_Valid_Check
7329 Related_Id
: Entity_Id
:= Empty
;
7330 Is_Low_Bound
: Boolean := False;
7331 Is_High_Bound
: Boolean := False)
7333 Loc
: constant Source_Ptr
:= Sloc
(Expr
);
7334 Typ
: constant Entity_Id
:= Etype
(Expr
);
7338 -- Do not insert if checks off, or if not checking validity or if
7339 -- expression is known to be valid.
7341 if not Validity_Checks_On
7342 or else Range_Or_Validity_Checks_Suppressed
(Expr
)
7343 or else Expr_Known_Valid
(Expr
)
7347 -- Do not insert checks within a predicate function. This will arise
7348 -- if the current unit and the predicate function are being compiled
7349 -- with validity checks enabled.
7351 elsif Present
(Predicate_Function
(Typ
))
7352 and then Current_Scope
= Predicate_Function
(Typ
)
7356 -- If the expression is a packed component of a modular type of the
7357 -- right size, the data is always valid.
7359 elsif Nkind
(Expr
) = N_Selected_Component
7360 and then Present
(Component_Clause
(Entity
(Selector_Name
(Expr
))))
7361 and then Is_Modular_Integer_Type
(Typ
)
7362 and then Modulus
(Typ
) = 2 ** Esize
(Entity
(Selector_Name
(Expr
)))
7366 -- Do not generate a validity check when inside a generic unit as this
7367 -- is an expansion activity.
7369 elsif Inside_A_Generic
then
7373 -- If we have a checked conversion, then validity check applies to
7374 -- the expression inside the conversion, not the result, since if
7375 -- the expression inside is valid, then so is the conversion result.
7378 while Nkind
(Exp
) = N_Type_Conversion
loop
7379 Exp
:= Expression
(Exp
);
7382 -- Do not generate a check for a variable which already validates the
7383 -- value of an assignable object.
7385 if Is_Validation_Variable_Reference
(Exp
) then
7395 -- If the expression denotes an assignable object, capture its value
7396 -- in a variable and replace the original expression by the variable.
7397 -- This approach has several effects:
7399 -- 1) The evaluation of the object results in only one read in the
7400 -- case where the object is atomic or volatile.
7402 -- Var ... := Object; -- read
7404 -- 2) The captured value is the one verified by attribute 'Valid.
7405 -- As a result the object is not evaluated again, which would
7406 -- result in an unwanted read in the case where the object is
7407 -- atomic or volatile.
7409 -- if not Var'Valid then -- OK, no read of Object
7411 -- if not Object'Valid then -- Wrong, extra read of Object
7413 -- 3) The captured value replaces the original object reference.
7414 -- As a result the object is not evaluated again, in the same
7417 -- ... Var ... -- OK, no read of Object
7419 -- ... Object ... -- Wrong, extra read of Object
7421 -- 4) The use of a variable to capture the value of the object
7422 -- allows the propagation of any changes back to the original
7425 -- procedure Call (Val : in out ...);
7427 -- Var : ... := Object; -- read Object
7428 -- if not Var'Valid then -- validity check
7429 -- Call (Var); -- modify Var
7430 -- Object := Var; -- update Object
7432 if Is_Variable
(Exp
) then
7433 Var_Id
:= Make_Temporary
(Loc
, 'T', Exp
);
7435 -- Because we could be dealing with a transient scope which would
7436 -- cause our object declaration to remain unanalyzed we must do
7437 -- some manual decoration.
7439 Set_Ekind
(Var_Id
, E_Variable
);
7440 Set_Etype
(Var_Id
, Typ
);
7443 Make_Object_Declaration
(Loc
,
7444 Defining_Identifier
=> Var_Id
,
7445 Object_Definition
=> New_Occurrence_Of
(Typ
, Loc
),
7446 Expression
=> New_Copy_Tree
(Exp
)),
7447 Suppress
=> Validity_Check
);
7449 Set_Validated_Object
(Var_Id
, New_Copy_Tree
(Exp
));
7450 Rewrite
(Exp
, New_Occurrence_Of
(Var_Id
, Loc
));
7451 PV
:= New_Occurrence_Of
(Var_Id
, Loc
);
7453 -- Copy the Do_Range_Check flag over to the new Exp, so it doesn't
7454 -- get lost. Floating point types are handled elsewhere.
7456 if not Is_Floating_Point_Type
(Typ
) then
7457 Set_Do_Range_Check
(Exp
, Do_Range_Check
(Original_Node
(Exp
)));
7460 -- Otherwise the expression does not denote a variable. Force its
7461 -- evaluation by capturing its value in a constant. Generate:
7463 -- Temp : constant ... := Exp;
7468 Related_Id
=> Related_Id
,
7469 Is_Low_Bound
=> Is_Low_Bound
,
7470 Is_High_Bound
=> Is_High_Bound
);
7472 PV
:= New_Copy_Tree
(Exp
);
7475 -- A rather specialized test. If PV is an analyzed expression which
7476 -- is an indexed component of a packed array that has not been
7477 -- properly expanded, turn off its Analyzed flag to make sure it
7478 -- gets properly reexpanded. If the prefix is an access value,
7479 -- the dereference will be added later.
7481 -- The reason this arises is that Duplicate_Subexpr_No_Checks did
7482 -- an analyze with the old parent pointer. This may point e.g. to
7483 -- a subprogram call, which deactivates this expansion.
7486 and then Nkind
(PV
) = N_Indexed_Component
7487 and then Is_Array_Type
(Etype
(Prefix
(PV
)))
7488 and then Present
(Packed_Array_Impl_Type
(Etype
(Prefix
(PV
))))
7490 Set_Analyzed
(PV
, False);
7493 -- Build the raise CE node to check for validity. We build a type
7494 -- qualification for the prefix, since it may not be of the form of
7495 -- a name, and we don't care in this context!
7498 Make_Raise_Constraint_Error
(Loc
,
7502 Make_Attribute_Reference
(Loc
,
7504 Attribute_Name
=> Name_Valid
)),
7505 Reason
=> CE_Invalid_Data
);
7507 -- Insert the validity check. Note that we do this with validity
7508 -- checks turned off, to avoid recursion, we do not want validity
7509 -- checks on the validity checking code itself.
7511 Insert_Action
(Expr
, CE
, Suppress
=> Validity_Check
);
7513 -- If the expression is a reference to an element of a bit-packed
7514 -- array, then it is rewritten as a renaming declaration. If the
7515 -- expression is an actual in a call, it has not been expanded,
7516 -- waiting for the proper point at which to do it. The same happens
7517 -- with renamings, so that we have to force the expansion now. This
7518 -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb
7521 if Is_Entity_Name
(Exp
)
7522 and then Nkind
(Parent
(Entity
(Exp
))) =
7523 N_Object_Renaming_Declaration
7526 Old_Exp
: constant Node_Id
:= Name
(Parent
(Entity
(Exp
)));
7528 if Nkind
(Old_Exp
) = N_Indexed_Component
7529 and then Is_Bit_Packed_Array
(Etype
(Prefix
(Old_Exp
)))
7531 Expand_Packed_Element_Reference
(Old_Exp
);
7536 end Insert_Valid_Check
;
7538 -------------------------------------
7539 -- Is_Signed_Integer_Arithmetic_Op --
7540 -------------------------------------
7542 function Is_Signed_Integer_Arithmetic_Op
(N
: Node_Id
) return Boolean is
7556 return Is_Signed_Integer_Type
(Etype
(N
));
7558 when N_Case_Expression
7561 return Is_Signed_Integer_Type
(Etype
(N
));
7566 end Is_Signed_Integer_Arithmetic_Op
;
7568 ----------------------------------
7569 -- Install_Null_Excluding_Check --
7570 ----------------------------------
7572 procedure Install_Null_Excluding_Check
(N
: Node_Id
) is
7573 Loc
: constant Source_Ptr
:= Sloc
(Parent
(N
));
7574 Typ
: constant Entity_Id
:= Etype
(N
);
7576 function Safe_To_Capture_In_Parameter_Value
return Boolean;
7577 -- Determines if it is safe to capture Known_Non_Null status for an
7578 -- the entity referenced by node N. The caller ensures that N is indeed
7579 -- an entity name. It is safe to capture the non-null status for an IN
7580 -- parameter when the reference occurs within a declaration that is sure
7581 -- to be executed as part of the declarative region.
7583 procedure Mark_Non_Null
;
7584 -- After installation of check, if the node in question is an entity
7585 -- name, then mark this entity as non-null if possible.
7587 function Safe_To_Capture_In_Parameter_Value
return Boolean is
7588 E
: constant Entity_Id
:= Entity
(N
);
7589 S
: constant Entity_Id
:= Current_Scope
;
7593 if Ekind
(E
) /= E_In_Parameter
then
7597 -- Two initial context checks. We must be inside a subprogram body
7598 -- with declarations and reference must not appear in nested scopes.
7600 if (Ekind
(S
) /= E_Function
and then Ekind
(S
) /= E_Procedure
)
7601 or else Scope
(E
) /= S
7606 S_Par
:= Parent
(Parent
(S
));
7608 if Nkind
(S_Par
) /= N_Subprogram_Body
7609 or else No
(Declarations
(S_Par
))
7619 -- Retrieve the declaration node of N (if any). Note that N
7620 -- may be a part of a complex initialization expression.
7624 while Present
(P
) loop
7626 -- If we have a short circuit form, and we are within the right
7627 -- hand expression, we return false, since the right hand side
7628 -- is not guaranteed to be elaborated.
7630 if Nkind
(P
) in N_Short_Circuit
7631 and then N
= Right_Opnd
(P
)
7636 -- Similarly, if we are in an if expression and not part of the
7637 -- condition, then we return False, since neither the THEN or
7638 -- ELSE dependent expressions will always be elaborated.
7640 if Nkind
(P
) = N_If_Expression
7641 and then N
/= First
(Expressions
(P
))
7646 -- If within a case expression, and not part of the expression,
7647 -- then return False, since a particular dependent expression
7648 -- may not always be elaborated
7650 if Nkind
(P
) = N_Case_Expression
7651 and then N
/= Expression
(P
)
7656 -- While traversing the parent chain, if node N belongs to a
7657 -- statement, then it may never appear in a declarative region.
7659 if Nkind
(P
) in N_Statement_Other_Than_Procedure_Call
7660 or else Nkind
(P
) = N_Procedure_Call_Statement
7665 -- If we are at a declaration, record it and exit
7667 if Nkind
(P
) in N_Declaration
7668 and then Nkind
(P
) not in N_Subprogram_Specification
7681 return List_Containing
(N_Decl
) = Declarations
(S_Par
);
7683 end Safe_To_Capture_In_Parameter_Value
;
7689 procedure Mark_Non_Null
is
7691 -- Only case of interest is if node N is an entity name
7693 if Is_Entity_Name
(N
) then
7695 -- For sure, we want to clear an indication that this is known to
7696 -- be null, since if we get past this check, it definitely is not.
7698 Set_Is_Known_Null
(Entity
(N
), False);
7700 -- We can mark the entity as known to be non-null if either it is
7701 -- safe to capture the value, or in the case of an IN parameter,
7702 -- which is a constant, if the check we just installed is in the
7703 -- declarative region of the subprogram body. In this latter case,
7704 -- a check is decisive for the rest of the body if the expression
7705 -- is sure to be elaborated, since we know we have to elaborate
7706 -- all declarations before executing the body.
7708 -- Couldn't this always be part of Safe_To_Capture_Value ???
7710 if Safe_To_Capture_Value
(N
, Entity
(N
))
7711 or else Safe_To_Capture_In_Parameter_Value
7713 Set_Is_Known_Non_Null
(Entity
(N
));
7718 -- Start of processing for Install_Null_Excluding_Check
7721 pragma Assert
(Is_Access_Type
(Typ
));
7723 -- No check inside a generic, check will be emitted in instance
7725 if Inside_A_Generic
then
7729 -- No check needed if known to be non-null
7731 if Known_Non_Null
(N
) then
7735 -- If known to be null, here is where we generate a compile time check
7737 if Known_Null
(N
) then
7739 -- Avoid generating warning message inside init procs. In SPARK mode
7740 -- we can go ahead and call Apply_Compile_Time_Constraint_Error
7741 -- since it will be turned into an error in any case.
7743 if (not Inside_Init_Proc
or else SPARK_Mode
= On
)
7745 -- Do not emit the warning within a conditional expression,
7746 -- where the expression might not be evaluated, and the warning
7747 -- appear as extraneous noise.
7749 and then not Within_Case_Or_If_Expression
(N
)
7751 Apply_Compile_Time_Constraint_Error
7752 (N
, "null value not allowed here??", CE_Access_Check_Failed
);
7754 -- Remaining cases, where we silently insert the raise
7758 Make_Raise_Constraint_Error
(Loc
,
7759 Reason
=> CE_Access_Check_Failed
));
7766 -- If entity is never assigned, for sure a warning is appropriate
7768 if Is_Entity_Name
(N
) then
7769 Check_Unset_Reference
(N
);
7772 -- No check needed if checks are suppressed on the range. Note that we
7773 -- don't set Is_Known_Non_Null in this case (we could legitimately do
7774 -- so, since the program is erroneous, but we don't like to casually
7775 -- propagate such conclusions from erroneosity).
7777 if Access_Checks_Suppressed
(Typ
) then
7781 -- No check needed for access to concurrent record types generated by
7782 -- the expander. This is not just an optimization (though it does indeed
7783 -- remove junk checks). It also avoids generation of junk warnings.
7785 if Nkind
(N
) in N_Has_Chars
7786 and then Chars
(N
) = Name_uObject
7787 and then Is_Concurrent_Record_Type
7788 (Directly_Designated_Type
(Etype
(N
)))
7793 -- No check needed in interface thunks since the runtime check is
7794 -- already performed at the caller side.
7796 if Is_Thunk
(Current_Scope
) then
7800 -- No check needed for the Get_Current_Excep.all.all idiom generated by
7801 -- the expander within exception handlers, since we know that the value
7802 -- can never be null.
7804 -- Is this really the right way to do this? Normally we generate such
7805 -- code in the expander with checks off, and that's how we suppress this
7806 -- kind of junk check ???
7808 if Nkind
(N
) = N_Function_Call
7809 and then Nkind
(Name
(N
)) = N_Explicit_Dereference
7810 and then Nkind
(Prefix
(Name
(N
))) = N_Identifier
7811 and then Is_RTE
(Entity
(Prefix
(Name
(N
))), RE_Get_Current_Excep
)
7816 -- Otherwise install access check
7819 Make_Raise_Constraint_Error
(Loc
,
7822 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(N
),
7823 Right_Opnd
=> Make_Null
(Loc
)),
7824 Reason
=> CE_Access_Check_Failed
));
7827 end Install_Null_Excluding_Check
;
7829 -----------------------------------------
7830 -- Install_Primitive_Elaboration_Check --
7831 -----------------------------------------
7833 procedure Install_Primitive_Elaboration_Check
(Subp_Body
: Node_Id
) is
7834 function Within_Compilation_Unit_Instance
7835 (Subp_Id
: Entity_Id
) return Boolean;
7836 -- Determine whether subprogram Subp_Id appears within an instance which
7837 -- acts as a compilation unit.
7839 --------------------------------------
7840 -- Within_Compilation_Unit_Instance --
7841 --------------------------------------
7843 function Within_Compilation_Unit_Instance
7844 (Subp_Id
: Entity_Id
) return Boolean
7849 -- Examine the scope chain looking for a compilation-unit-level
7852 Pack
:= Scope
(Subp_Id
);
7853 while Present
(Pack
) and then Pack
/= Standard_Standard
loop
7854 if Ekind
(Pack
) = E_Package
7855 and then Is_Generic_Instance
(Pack
)
7856 and then Nkind
(Parent
(Unit_Declaration_Node
(Pack
))) =
7862 Pack
:= Scope
(Pack
);
7866 end Within_Compilation_Unit_Instance
;
7868 -- Local declarations
7870 Context
: constant Node_Id
:= Parent
(Subp_Body
);
7871 Loc
: constant Source_Ptr
:= Sloc
(Subp_Body
);
7872 Subp_Id
: constant Entity_Id
:= Unique_Defining_Entity
(Subp_Body
);
7873 Subp_Decl
: constant Node_Id
:= Unit_Declaration_Node
(Subp_Id
);
7876 Flag_Id
: Entity_Id
;
7879 Tag_Typ
: Entity_Id
;
7881 -- Start of processing for Install_Primitive_Elaboration_Check
7884 -- Do not generate an elaboration check in compilation modes where
7885 -- expansion is not desirable.
7887 if ASIS_Mode
or GNATprove_Mode
then
7890 -- Do not generate an elaboration check if all checks have been
7893 elsif Suppress_Checks
then
7896 -- Do not generate an elaboration check if the related subprogram is
7897 -- not subjected to accessibility checks.
7899 elsif Elaboration_Checks_Suppressed
(Subp_Id
) then
7902 -- Do not generate an elaboration check if such code is not desirable
7904 elsif Restriction_Active
(No_Elaboration_Code
) then
7907 -- Do not consider subprograms which act as compilation units, because
7908 -- they cannot be the target of a dispatching call.
7910 elsif Nkind
(Context
) = N_Compilation_Unit
then
7913 -- Do not consider anything other than nonabstract library-level source
7917 (Comes_From_Source
(Subp_Id
)
7918 and then Is_Library_Level_Entity
(Subp_Id
)
7919 and then Is_Primitive
(Subp_Id
)
7920 and then not Is_Abstract_Subprogram
(Subp_Id
))
7924 -- Do not consider inlined primitives, because once the body is inlined
7925 -- the reference to the elaboration flag will be out of place and will
7926 -- result in an undefined symbol.
7928 elsif Is_Inlined
(Subp_Id
) or else Has_Pragma_Inline
(Subp_Id
) then
7931 -- Do not generate a duplicate elaboration check. This happens only in
7932 -- the case of primitives completed by an expression function, as the
7933 -- corresponding body is apparently analyzed and expanded twice.
7935 elsif Analyzed
(Subp_Body
) then
7938 -- Do not consider primitives which occur within an instance that acts
7939 -- as a compilation unit. Such an instance defines its spec and body out
7940 -- of order (body is first) within the tree, which causes the reference
7941 -- to the elaboration flag to appear as an undefined symbol.
7943 elsif Within_Compilation_Unit_Instance
(Subp_Id
) then
7947 Tag_Typ
:= Find_Dispatching_Type
(Subp_Id
);
7949 -- Only tagged primitives may be the target of a dispatching call
7951 if No
(Tag_Typ
) then
7954 -- Do not consider finalization-related primitives, because they may
7955 -- need to be called while elaboration is taking place.
7957 elsif Is_Controlled
(Tag_Typ
)
7958 and then Nam_In
(Chars
(Subp_Id
), Name_Adjust
,
7965 -- Create the declaration of the elaboration flag. The name carries a
7966 -- unique counter in case of name overloading.
7969 Make_Defining_Identifier
(Loc
,
7970 Chars
=> New_External_Name
(Chars
(Subp_Id
), 'E', -1));
7971 Set_Is_Frozen
(Flag_Id
);
7973 -- Insert the declaration of the elaboration flag in front of the
7974 -- primitive spec and analyze it in the proper context.
7976 Push_Scope
(Scope
(Subp_Id
));
7979 -- E : Boolean := False;
7981 Insert_Action
(Subp_Decl
,
7982 Make_Object_Declaration
(Loc
,
7983 Defining_Identifier
=> Flag_Id
,
7984 Object_Definition
=> New_Occurrence_Of
(Standard_Boolean
, Loc
),
7985 Expression
=> New_Occurrence_Of
(Standard_False
, Loc
)));
7988 -- Prevent the compiler from optimizing the elaboration check by killing
7989 -- the current value of the flag and the associated assignment.
7991 Set_Current_Value
(Flag_Id
, Empty
);
7992 Set_Last_Assignment
(Flag_Id
, Empty
);
7994 -- Add a check at the top of the body declarations to ensure that the
7995 -- elaboration flag has been set.
7997 Decls
:= Declarations
(Subp_Body
);
8001 Set_Declarations
(Subp_Body
, Decls
);
8006 -- raise Program_Error with "access before elaboration";
8010 Make_Raise_Program_Error
(Loc
,
8013 Right_Opnd
=> New_Occurrence_Of
(Flag_Id
, Loc
)),
8014 Reason
=> PE_Access_Before_Elaboration
));
8016 Analyze
(First
(Decls
));
8018 -- Set the elaboration flag once the body has been elaborated. Insert
8019 -- the statement after the subprogram stub when the primitive body is
8022 if Nkind
(Context
) = N_Subunit
then
8023 Set_Ins
:= Corresponding_Stub
(Context
);
8025 Set_Ins
:= Subp_Body
;
8032 Make_Assignment_Statement
(Loc
,
8033 Name
=> New_Occurrence_Of
(Flag_Id
, Loc
),
8034 Expression
=> New_Occurrence_Of
(Standard_True
, Loc
));
8036 -- Mark the assignment statement as elaboration code. This allows the
8037 -- early call region mechanism (see Sem_Elab) to properly ignore such
8038 -- assignments even though they are non-preelaborable code.
8040 Set_Is_Elaboration_Code
(Set_Stmt
);
8042 Insert_After_And_Analyze
(Set_Ins
, Set_Stmt
);
8043 end Install_Primitive_Elaboration_Check
;
8045 --------------------------
8046 -- Install_Static_Check --
8047 --------------------------
8049 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
) is
8050 Stat
: constant Boolean := Is_OK_Static_Expression
(R_Cno
);
8051 Typ
: constant Entity_Id
:= Etype
(R_Cno
);
8055 Make_Raise_Constraint_Error
(Loc
,
8056 Reason
=> CE_Range_Check_Failed
));
8057 Set_Analyzed
(R_Cno
);
8058 Set_Etype
(R_Cno
, Typ
);
8059 Set_Raises_Constraint_Error
(R_Cno
);
8060 Set_Is_Static_Expression
(R_Cno
, Stat
);
8062 -- Now deal with possible local raise handling
8064 Possible_Local_Raise
(R_Cno
, Standard_Constraint_Error
);
8065 end Install_Static_Check
;
8067 -------------------------
8068 -- Is_Check_Suppressed --
8069 -------------------------
8071 function Is_Check_Suppressed
(E
: Entity_Id
; C
: Check_Id
) return Boolean is
8072 Ptr
: Suppress_Stack_Entry_Ptr
;
8075 -- First search the local entity suppress stack. We search this from the
8076 -- top of the stack down so that we get the innermost entry that applies
8077 -- to this case if there are nested entries.
8079 Ptr
:= Local_Suppress_Stack_Top
;
8080 while Ptr
/= null loop
8081 if (Ptr
.Entity
= Empty
or else Ptr
.Entity
= E
)
8082 and then (Ptr
.Check
= All_Checks
or else Ptr
.Check
= C
)
8084 return Ptr
.Suppress
;
8090 -- Now search the global entity suppress table for a matching entry.
8091 -- We also search this from the top down so that if there are multiple
8092 -- pragmas for the same entity, the last one applies (not clear what
8093 -- or whether the RM specifies this handling, but it seems reasonable).
8095 Ptr
:= Global_Suppress_Stack_Top
;
8096 while Ptr
/= null loop
8097 if (Ptr
.Entity
= Empty
or else Ptr
.Entity
= E
)
8098 and then (Ptr
.Check
= All_Checks
or else Ptr
.Check
= C
)
8100 return Ptr
.Suppress
;
8106 -- If we did not find a matching entry, then use the normal scope
8107 -- suppress value after all (actually this will be the global setting
8108 -- since it clearly was not overridden at any point). For a predefined
8109 -- check, we test the specific flag. For a user defined check, we check
8110 -- the All_Checks flag. The Overflow flag requires special handling to
8111 -- deal with the General vs Assertion case.
8113 if C
= Overflow_Check
then
8114 return Overflow_Checks_Suppressed
(Empty
);
8116 elsif C
in Predefined_Check_Id
then
8117 return Scope_Suppress
.Suppress
(C
);
8120 return Scope_Suppress
.Suppress
(All_Checks
);
8122 end Is_Check_Suppressed
;
8124 ---------------------
8125 -- Kill_All_Checks --
8126 ---------------------
8128 procedure Kill_All_Checks
is
8130 if Debug_Flag_CC
then
8131 w
("Kill_All_Checks");
8134 -- We reset the number of saved checks to zero, and also modify all
8135 -- stack entries for statement ranges to indicate that the number of
8136 -- checks at each level is now zero.
8138 Num_Saved_Checks
:= 0;
8140 -- Note: the Int'Min here avoids any possibility of J being out of
8141 -- range when called from e.g. Conditional_Statements_Begin.
8143 for J
in 1 .. Int
'Min (Saved_Checks_TOS
, Saved_Checks_Stack
'Last) loop
8144 Saved_Checks_Stack
(J
) := 0;
8146 end Kill_All_Checks
;
8152 procedure Kill_Checks
(V
: Entity_Id
) is
8154 if Debug_Flag_CC
then
8155 w
("Kill_Checks for entity", Int
(V
));
8158 for J
in 1 .. Num_Saved_Checks
loop
8159 if Saved_Checks
(J
).Entity
= V
then
8160 if Debug_Flag_CC
then
8161 w
(" Checks killed for saved check ", J
);
8164 Saved_Checks
(J
).Killed
:= True;
8169 ------------------------------
8170 -- Length_Checks_Suppressed --
8171 ------------------------------
8173 function Length_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
8175 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
8176 return Is_Check_Suppressed
(E
, Length_Check
);
8178 return Scope_Suppress
.Suppress
(Length_Check
);
8180 end Length_Checks_Suppressed
;
8182 -----------------------
8183 -- Make_Bignum_Block --
8184 -----------------------
8186 function Make_Bignum_Block
(Loc
: Source_Ptr
) return Node_Id
is
8187 M
: constant Entity_Id
:= Make_Defining_Identifier
(Loc
, Name_uM
);
8190 Make_Block_Statement
(Loc
,
8192 New_List
(Build_SS_Mark_Call
(Loc
, M
)),
8193 Handled_Statement_Sequence
=>
8194 Make_Handled_Sequence_Of_Statements
(Loc
,
8195 Statements
=> New_List
(Build_SS_Release_Call
(Loc
, M
))));
8196 end Make_Bignum_Block
;
8198 ----------------------------------
8199 -- Minimize_Eliminate_Overflows --
8200 ----------------------------------
8202 -- This is a recursive routine that is called at the top of an expression
8203 -- tree to properly process overflow checking for a whole subtree by making
8204 -- recursive calls to process operands. This processing may involve the use
8205 -- of bignum or long long integer arithmetic, which will change the types
8206 -- of operands and results. That's why we can't do this bottom up (since
8207 -- it would interfere with semantic analysis).
8209 -- What happens is that if MINIMIZED/ELIMINATED mode is in effect then
8210 -- the operator expansion routines, as well as the expansion routines for
8211 -- if/case expression, do nothing (for the moment) except call the routine
8212 -- to apply the overflow check (Apply_Arithmetic_Overflow_Check). That
8213 -- routine does nothing for non top-level nodes, so at the point where the
8214 -- call is made for the top level node, the entire expression subtree has
8215 -- not been expanded, or processed for overflow. All that has to happen as
8216 -- a result of the top level call to this routine.
8218 -- As noted above, the overflow processing works by making recursive calls
8219 -- for the operands, and figuring out what to do, based on the processing
8220 -- of these operands (e.g. if a bignum operand appears, the parent op has
8221 -- to be done in bignum mode), and the determined ranges of the operands.
8223 -- After possible rewriting of a constituent subexpression node, a call is
8224 -- made to either reexpand the node (if nothing has changed) or reanalyze
8225 -- the node (if it has been modified by the overflow check processing). The
8226 -- Analyzed_Flag is set to False before the reexpand/reanalyze. To avoid
8227 -- a recursive call into the whole overflow apparatus, an important rule
8228 -- for this call is that the overflow handling mode must be temporarily set
8231 procedure Minimize_Eliminate_Overflows
8235 Top_Level
: Boolean)
8237 Rtyp
: constant Entity_Id
:= Etype
(N
);
8238 pragma Assert
(Is_Signed_Integer_Type
(Rtyp
));
8239 -- Result type, must be a signed integer type
8241 Check_Mode
: constant Overflow_Mode_Type
:= Overflow_Check_Mode
;
8242 pragma Assert
(Check_Mode
in Minimized_Or_Eliminated
);
8244 Loc
: constant Source_Ptr
:= Sloc
(N
);
8247 -- Ranges of values for right operand (operator case)
8249 Llo
: Uint
:= No_Uint
; -- initialize to prevent warning
8250 Lhi
: Uint
:= No_Uint
; -- initialize to prevent warning
8251 -- Ranges of values for left operand (operator case)
8253 LLIB
: constant Entity_Id
:= Base_Type
(Standard_Long_Long_Integer
);
8254 -- Operands and results are of this type when we convert
8256 LLLo
: constant Uint
:= Intval
(Type_Low_Bound
(LLIB
));
8257 LLHi
: constant Uint
:= Intval
(Type_High_Bound
(LLIB
));
8258 -- Bounds of Long_Long_Integer
8260 Binary
: constant Boolean := Nkind
(N
) in N_Binary_Op
;
8261 -- Indicates binary operator case
8264 -- Used in call to Determine_Range
8266 Bignum_Operands
: Boolean;
8267 -- Set True if one or more operands is already of type Bignum, meaning
8268 -- that for sure (regardless of Top_Level setting) we are committed to
8269 -- doing the operation in Bignum mode (or in the case of a case or if
8270 -- expression, converting all the dependent expressions to Bignum).
8272 Long_Long_Integer_Operands
: Boolean;
8273 -- Set True if one or more operands is already of type Long_Long_Integer
8274 -- which means that if the result is known to be in the result type
8275 -- range, then we must convert such operands back to the result type.
8277 procedure Reanalyze
(Typ
: Entity_Id
; Suppress
: Boolean := False);
8278 -- This is called when we have modified the node and we therefore need
8279 -- to reanalyze it. It is important that we reset the mode to STRICT for
8280 -- this reanalysis, since if we leave it in MINIMIZED or ELIMINATED mode
8281 -- we would reenter this routine recursively which would not be good.
8282 -- The argument Suppress is set True if we also want to suppress
8283 -- overflow checking for the reexpansion (this is set when we know
8284 -- overflow is not possible). Typ is the type for the reanalysis.
8286 procedure Reexpand
(Suppress
: Boolean := False);
8287 -- This is like Reanalyze, but does not do the Analyze step, it only
8288 -- does a reexpansion. We do this reexpansion in STRICT mode, so that
8289 -- instead of reentering the MINIMIZED/ELIMINATED mode processing, we
8290 -- follow the normal expansion path (e.g. converting A**4 to A**2**2).
8291 -- Note that skipping reanalysis is not just an optimization, testing
8292 -- has showed up several complex cases in which reanalyzing an already
8293 -- analyzed node causes incorrect behavior.
8295 function In_Result_Range
return Boolean;
8296 -- Returns True iff Lo .. Hi are within range of the result type
8298 procedure Max
(A
: in out Uint
; B
: Uint
);
8299 -- If A is No_Uint, sets A to B, else to UI_Max (A, B)
8301 procedure Min
(A
: in out Uint
; B
: Uint
);
8302 -- If A is No_Uint, sets A to B, else to UI_Min (A, B)
8304 ---------------------
8305 -- In_Result_Range --
8306 ---------------------
8308 function In_Result_Range
return Boolean is
8310 if Lo
= No_Uint
or else Hi
= No_Uint
then
8313 elsif Is_OK_Static_Subtype
(Etype
(N
)) then
8314 return Lo
>= Expr_Value
(Type_Low_Bound
(Rtyp
))
8316 Hi
<= Expr_Value
(Type_High_Bound
(Rtyp
));
8319 return Lo
>= Expr_Value
(Type_Low_Bound
(Base_Type
(Rtyp
)))
8321 Hi
<= Expr_Value
(Type_High_Bound
(Base_Type
(Rtyp
)));
8323 end In_Result_Range
;
8329 procedure Max
(A
: in out Uint
; B
: Uint
) is
8331 if A
= No_Uint
or else B
> A
then
8340 procedure Min
(A
: in out Uint
; B
: Uint
) is
8342 if A
= No_Uint
or else B
< A
then
8351 procedure Reanalyze
(Typ
: Entity_Id
; Suppress
: Boolean := False) is
8352 Svg
: constant Overflow_Mode_Type
:=
8353 Scope_Suppress
.Overflow_Mode_General
;
8354 Sva
: constant Overflow_Mode_Type
:=
8355 Scope_Suppress
.Overflow_Mode_Assertions
;
8356 Svo
: constant Boolean :=
8357 Scope_Suppress
.Suppress
(Overflow_Check
);
8360 Scope_Suppress
.Overflow_Mode_General
:= Strict
;
8361 Scope_Suppress
.Overflow_Mode_Assertions
:= Strict
;
8364 Scope_Suppress
.Suppress
(Overflow_Check
) := True;
8367 Analyze_And_Resolve
(N
, Typ
);
8369 Scope_Suppress
.Suppress
(Overflow_Check
) := Svo
;
8370 Scope_Suppress
.Overflow_Mode_General
:= Svg
;
8371 Scope_Suppress
.Overflow_Mode_Assertions
:= Sva
;
8378 procedure Reexpand
(Suppress
: Boolean := False) is
8379 Svg
: constant Overflow_Mode_Type
:=
8380 Scope_Suppress
.Overflow_Mode_General
;
8381 Sva
: constant Overflow_Mode_Type
:=
8382 Scope_Suppress
.Overflow_Mode_Assertions
;
8383 Svo
: constant Boolean :=
8384 Scope_Suppress
.Suppress
(Overflow_Check
);
8387 Scope_Suppress
.Overflow_Mode_General
:= Strict
;
8388 Scope_Suppress
.Overflow_Mode_Assertions
:= Strict
;
8389 Set_Analyzed
(N
, False);
8392 Scope_Suppress
.Suppress
(Overflow_Check
) := True;
8397 Scope_Suppress
.Suppress
(Overflow_Check
) := Svo
;
8398 Scope_Suppress
.Overflow_Mode_General
:= Svg
;
8399 Scope_Suppress
.Overflow_Mode_Assertions
:= Sva
;
8402 -- Start of processing for Minimize_Eliminate_Overflows
8405 -- Default initialize Lo and Hi since these are not guaranteed to be
8411 -- Case where we do not have a signed integer arithmetic operation
8413 if not Is_Signed_Integer_Arithmetic_Op
(N
) then
8415 -- Use the normal Determine_Range routine to get the range. We
8416 -- don't require operands to be valid, invalid values may result in
8417 -- rubbish results where the result has not been properly checked for
8418 -- overflow, that's fine.
8420 Determine_Range
(N
, OK
, Lo
, Hi
, Assume_Valid
=> False);
8422 -- If Determine_Range did not work (can this in fact happen? Not
8423 -- clear but might as well protect), use type bounds.
8426 Lo
:= Intval
(Type_Low_Bound
(Base_Type
(Etype
(N
))));
8427 Hi
:= Intval
(Type_High_Bound
(Base_Type
(Etype
(N
))));
8430 -- If we don't have a binary operator, all we have to do is to set
8431 -- the Hi/Lo range, so we are done.
8435 -- Processing for if expression
8437 elsif Nkind
(N
) = N_If_Expression
then
8439 Then_DE
: constant Node_Id
:= Next
(First
(Expressions
(N
)));
8440 Else_DE
: constant Node_Id
:= Next
(Then_DE
);
8443 Bignum_Operands
:= False;
8445 Minimize_Eliminate_Overflows
8446 (Then_DE
, Lo
, Hi
, Top_Level
=> False);
8448 if Lo
= No_Uint
then
8449 Bignum_Operands
:= True;
8452 Minimize_Eliminate_Overflows
8453 (Else_DE
, Rlo
, Rhi
, Top_Level
=> False);
8455 if Rlo
= No_Uint
then
8456 Bignum_Operands
:= True;
8458 Long_Long_Integer_Operands
:=
8459 Etype
(Then_DE
) = LLIB
or else Etype
(Else_DE
) = LLIB
;
8465 -- If at least one of our operands is now Bignum, we must rebuild
8466 -- the if expression to use Bignum operands. We will analyze the
8467 -- rebuilt if expression with overflow checks off, since once we
8468 -- are in bignum mode, we are all done with overflow checks.
8470 if Bignum_Operands
then
8472 Make_If_Expression
(Loc
,
8473 Expressions
=> New_List
(
8474 Remove_Head
(Expressions
(N
)),
8475 Convert_To_Bignum
(Then_DE
),
8476 Convert_To_Bignum
(Else_DE
)),
8477 Is_Elsif
=> Is_Elsif
(N
)));
8479 Reanalyze
(RTE
(RE_Bignum
), Suppress
=> True);
8481 -- If we have no Long_Long_Integer operands, then we are in result
8482 -- range, since it means that none of our operands felt the need
8483 -- to worry about overflow (otherwise it would have already been
8484 -- converted to long long integer or bignum). We reexpand to
8485 -- complete the expansion of the if expression (but we do not
8486 -- need to reanalyze).
8488 elsif not Long_Long_Integer_Operands
then
8489 Set_Do_Overflow_Check
(N
, False);
8492 -- Otherwise convert us to long long integer mode. Note that we
8493 -- don't need any further overflow checking at this level.
8496 Convert_To_And_Rewrite
(LLIB
, Then_DE
);
8497 Convert_To_And_Rewrite
(LLIB
, Else_DE
);
8498 Set_Etype
(N
, LLIB
);
8500 -- Now reanalyze with overflow checks off
8502 Set_Do_Overflow_Check
(N
, False);
8503 Reanalyze
(LLIB
, Suppress
=> True);
8509 -- Here for case expression
8511 elsif Nkind
(N
) = N_Case_Expression
then
8512 Bignum_Operands
:= False;
8513 Long_Long_Integer_Operands
:= False;
8519 -- Loop through expressions applying recursive call
8521 Alt
:= First
(Alternatives
(N
));
8522 while Present
(Alt
) loop
8524 Aexp
: constant Node_Id
:= Expression
(Alt
);
8527 Minimize_Eliminate_Overflows
8528 (Aexp
, Lo
, Hi
, Top_Level
=> False);
8530 if Lo
= No_Uint
then
8531 Bignum_Operands
:= True;
8532 elsif Etype
(Aexp
) = LLIB
then
8533 Long_Long_Integer_Operands
:= True;
8540 -- If we have no bignum or long long integer operands, it means
8541 -- that none of our dependent expressions could raise overflow.
8542 -- In this case, we simply return with no changes except for
8543 -- resetting the overflow flag, since we are done with overflow
8544 -- checks for this node. We will reexpand to get the needed
8545 -- expansion for the case expression, but we do not need to
8546 -- reanalyze, since nothing has changed.
8548 if not (Bignum_Operands
or Long_Long_Integer_Operands
) then
8549 Set_Do_Overflow_Check
(N
, False);
8550 Reexpand
(Suppress
=> True);
8552 -- Otherwise we are going to rebuild the case expression using
8553 -- either bignum or long long integer operands throughout.
8558 pragma Warnings
(Off
, Rtype
);
8563 New_Alts
:= New_List
;
8564 Alt
:= First
(Alternatives
(N
));
8565 while Present
(Alt
) loop
8566 if Bignum_Operands
then
8567 New_Exp
:= Convert_To_Bignum
(Expression
(Alt
));
8568 Rtype
:= RTE
(RE_Bignum
);
8570 New_Exp
:= Convert_To
(LLIB
, Expression
(Alt
));
8574 Append_To
(New_Alts
,
8575 Make_Case_Expression_Alternative
(Sloc
(Alt
),
8577 Discrete_Choices
=> Discrete_Choices
(Alt
),
8578 Expression
=> New_Exp
));
8584 Make_Case_Expression
(Loc
,
8585 Expression
=> Expression
(N
),
8586 Alternatives
=> New_Alts
));
8588 Reanalyze
(Rtype
, Suppress
=> True);
8596 -- If we have an arithmetic operator we make recursive calls on the
8597 -- operands to get the ranges (and to properly process the subtree
8598 -- that lies below us).
8600 Minimize_Eliminate_Overflows
8601 (Right_Opnd
(N
), Rlo
, Rhi
, Top_Level
=> False);
8604 Minimize_Eliminate_Overflows
8605 (Left_Opnd
(N
), Llo
, Lhi
, Top_Level
=> False);
8608 -- Record if we have Long_Long_Integer operands
8610 Long_Long_Integer_Operands
:=
8611 Etype
(Right_Opnd
(N
)) = LLIB
8612 or else (Binary
and then Etype
(Left_Opnd
(N
)) = LLIB
);
8614 -- If either operand is a bignum, then result will be a bignum and we
8615 -- don't need to do any range analysis. As previously discussed we could
8616 -- do range analysis in such cases, but it could mean working with giant
8617 -- numbers at compile time for very little gain (the number of cases
8618 -- in which we could slip back from bignum mode is small).
8620 if Rlo
= No_Uint
or else (Binary
and then Llo
= No_Uint
) then
8623 Bignum_Operands
:= True;
8625 -- Otherwise compute result range
8628 Bignum_Operands
:= False;
8636 Hi
:= UI_Max
(abs Rlo
, abs Rhi
);
8648 -- If the right operand can only be zero, set 0..0
8650 if Rlo
= 0 and then Rhi
= 0 then
8654 -- Possible bounds of division must come from dividing end
8655 -- values of the input ranges (four possibilities), provided
8656 -- zero is not included in the possible values of the right
8659 -- Otherwise, we just consider two intervals of values for
8660 -- the right operand: the interval of negative values (up to
8661 -- -1) and the interval of positive values (starting at 1).
8662 -- Since division by 1 is the identity, and division by -1
8663 -- is negation, we get all possible bounds of division in that
8664 -- case by considering:
8665 -- - all values from the division of end values of input
8667 -- - the end values of the left operand;
8668 -- - the negation of the end values of the left operand.
8672 Mrk
: constant Uintp
.Save_Mark
:= Mark
;
8673 -- Mark so we can release the RR and Ev values
8681 -- Discard extreme values of zero for the divisor, since
8682 -- they will simply result in an exception in any case.
8690 -- Compute possible bounds coming from dividing end
8691 -- values of the input ranges.
8698 Lo
:= UI_Min
(UI_Min
(Ev1
, Ev2
), UI_Min
(Ev3
, Ev4
));
8699 Hi
:= UI_Max
(UI_Max
(Ev1
, Ev2
), UI_Max
(Ev3
, Ev4
));
8701 -- If the right operand can be both negative or positive,
8702 -- include the end values of the left operand in the
8703 -- extreme values, as well as their negation.
8705 if Rlo
< 0 and then Rhi
> 0 then
8712 UI_Min
(UI_Min
(Ev1
, Ev2
), UI_Min
(Ev3
, Ev4
)));
8714 UI_Max
(UI_Max
(Ev1
, Ev2
), UI_Max
(Ev3
, Ev4
)));
8717 -- Release the RR and Ev values
8719 Release_And_Save
(Mrk
, Lo
, Hi
);
8727 -- Discard negative values for the exponent, since they will
8728 -- simply result in an exception in any case.
8736 -- Estimate number of bits in result before we go computing
8737 -- giant useless bounds. Basically the number of bits in the
8738 -- result is the number of bits in the base multiplied by the
8739 -- value of the exponent. If this is big enough that the result
8740 -- definitely won't fit in Long_Long_Integer, switch to bignum
8741 -- mode immediately, and avoid computing giant bounds.
8743 -- The comparison here is approximate, but conservative, it
8744 -- only clicks on cases that are sure to exceed the bounds.
8746 if Num_Bits
(UI_Max
(abs Llo
, abs Lhi
)) * Rhi
+ 1 > 100 then
8750 -- If right operand is zero then result is 1
8757 -- High bound comes either from exponentiation of largest
8758 -- positive value to largest exponent value, or from
8759 -- the exponentiation of most negative value to an
8773 if Rhi
mod 2 = 0 then
8776 Hi2
:= Llo
** (Rhi
- 1);
8782 Hi
:= UI_Max
(Hi1
, Hi2
);
8785 -- Result can only be negative if base can be negative
8788 if Rhi
mod 2 = 0 then
8789 Lo
:= Llo
** (Rhi
- 1);
8794 -- Otherwise low bound is minimum ** minimum
8811 Maxabs
: constant Uint
:= UI_Max
(abs Rlo
, abs Rhi
) - 1;
8812 -- This is the maximum absolute value of the result
8818 -- The result depends only on the sign and magnitude of
8819 -- the right operand, it does not depend on the sign or
8820 -- magnitude of the left operand.
8833 when N_Op_Multiply
=>
8835 -- Possible bounds of multiplication must come from multiplying
8836 -- end values of the input ranges (four possibilities).
8839 Mrk
: constant Uintp
.Save_Mark
:= Mark
;
8840 -- Mark so we can release the Ev values
8842 Ev1
: constant Uint
:= Llo
* Rlo
;
8843 Ev2
: constant Uint
:= Llo
* Rhi
;
8844 Ev3
: constant Uint
:= Lhi
* Rlo
;
8845 Ev4
: constant Uint
:= Lhi
* Rhi
;
8848 Lo
:= UI_Min
(UI_Min
(Ev1
, Ev2
), UI_Min
(Ev3
, Ev4
));
8849 Hi
:= UI_Max
(UI_Max
(Ev1
, Ev2
), UI_Max
(Ev3
, Ev4
));
8851 -- Release the Ev values
8853 Release_And_Save
(Mrk
, Lo
, Hi
);
8856 -- Plus operator (affirmation)
8866 Maxabs
: constant Uint
:= UI_Max
(abs Rlo
, abs Rhi
) - 1;
8867 -- This is the maximum absolute value of the result. Note
8868 -- that the result range does not depend on the sign of the
8875 -- Case of left operand negative, which results in a range
8876 -- of -Maxabs .. 0 for those negative values. If there are
8877 -- no negative values then Lo value of result is always 0.
8883 -- Case of left operand positive
8892 when N_Op_Subtract
=>
8896 -- Nothing else should be possible
8899 raise Program_Error
;
8903 -- Here for the case where we have not rewritten anything (no bignum
8904 -- operands or long long integer operands), and we know the result.
8905 -- If we know we are in the result range, and we do not have Bignum
8906 -- operands or Long_Long_Integer operands, we can just reexpand with
8907 -- overflow checks turned off (since we know we cannot have overflow).
8908 -- As always the reexpansion is required to complete expansion of the
8909 -- operator, but we do not need to reanalyze, and we prevent recursion
8910 -- by suppressing the check.
8912 if not (Bignum_Operands
or Long_Long_Integer_Operands
)
8913 and then In_Result_Range
8915 Set_Do_Overflow_Check
(N
, False);
8916 Reexpand
(Suppress
=> True);
8919 -- Here we know that we are not in the result range, and in the general
8920 -- case we will move into either the Bignum or Long_Long_Integer domain
8921 -- to compute the result. However, there is one exception. If we are
8922 -- at the top level, and we do not have Bignum or Long_Long_Integer
8923 -- operands, we will have to immediately convert the result back to
8924 -- the result type, so there is no point in Bignum/Long_Long_Integer
8928 and then not (Bignum_Operands
or Long_Long_Integer_Operands
)
8930 -- One further refinement. If we are at the top level, but our parent
8931 -- is a type conversion, then go into bignum or long long integer node
8932 -- since the result will be converted to that type directly without
8933 -- going through the result type, and we may avoid an overflow. This
8934 -- is the case for example of Long_Long_Integer (A ** 4), where A is
8935 -- of type Integer, and the result A ** 4 fits in Long_Long_Integer
8936 -- but does not fit in Integer.
8938 and then Nkind
(Parent
(N
)) /= N_Type_Conversion
8940 -- Here keep original types, but we need to complete analysis
8942 -- One subtlety. We can't just go ahead and do an analyze operation
8943 -- here because it will cause recursion into the whole MINIMIZED/
8944 -- ELIMINATED overflow processing which is not what we want. Here
8945 -- we are at the top level, and we need a check against the result
8946 -- mode (i.e. we want to use STRICT mode). So do exactly that.
8947 -- Also, we have not modified the node, so this is a case where
8948 -- we need to reexpand, but not reanalyze.
8953 -- Cases where we do the operation in Bignum mode. This happens either
8954 -- because one of our operands is in Bignum mode already, or because
8955 -- the computed bounds are outside the bounds of Long_Long_Integer,
8956 -- which in some cases can be indicated by Hi and Lo being No_Uint.
8958 -- Note: we could do better here and in some cases switch back from
8959 -- Bignum mode to normal mode, e.g. big mod 2 must be in the range
8960 -- 0 .. 1, but the cases are rare and it is not worth the effort.
8961 -- Failing to do this switching back is only an efficiency issue.
8963 elsif Lo
= No_Uint
or else Lo
< LLLo
or else Hi
> LLHi
then
8965 -- OK, we are definitely outside the range of Long_Long_Integer. The
8966 -- question is whether to move to Bignum mode, or stay in the domain
8967 -- of Long_Long_Integer, signalling that an overflow check is needed.
8969 -- Obviously in MINIMIZED mode we stay with LLI, since we are not in
8970 -- the Bignum business. In ELIMINATED mode, we will normally move
8971 -- into Bignum mode, but there is an exception if neither of our
8972 -- operands is Bignum now, and we are at the top level (Top_Level
8973 -- set True). In this case, there is no point in moving into Bignum
8974 -- mode to prevent overflow if the caller will immediately convert
8975 -- the Bignum value back to LLI with an overflow check. It's more
8976 -- efficient to stay in LLI mode with an overflow check (if needed)
8978 if Check_Mode
= Minimized
8979 or else (Top_Level
and not Bignum_Operands
)
8981 if Do_Overflow_Check
(N
) then
8982 Enable_Overflow_Check
(N
);
8985 -- The result now has to be in Long_Long_Integer mode, so adjust
8986 -- the possible range to reflect this. Note these calls also
8987 -- change No_Uint values from the top level case to LLI bounds.
8992 -- Otherwise we are in ELIMINATED mode and we switch to Bignum mode
8995 pragma Assert
(Check_Mode
= Eliminated
);
9004 Fent
:= RTE
(RE_Big_Abs
);
9007 Fent
:= RTE
(RE_Big_Add
);
9010 Fent
:= RTE
(RE_Big_Div
);
9013 Fent
:= RTE
(RE_Big_Exp
);
9016 Fent
:= RTE
(RE_Big_Neg
);
9019 Fent
:= RTE
(RE_Big_Mod
);
9021 when N_Op_Multiply
=>
9022 Fent
:= RTE
(RE_Big_Mul
);
9025 Fent
:= RTE
(RE_Big_Rem
);
9027 when N_Op_Subtract
=>
9028 Fent
:= RTE
(RE_Big_Sub
);
9030 -- Anything else is an internal error, this includes the
9031 -- N_Op_Plus case, since how can plus cause the result
9032 -- to be out of range if the operand is in range?
9035 raise Program_Error
;
9038 -- Construct argument list for Bignum call, converting our
9039 -- operands to Bignum form if they are not already there.
9044 Append_To
(Args
, Convert_To_Bignum
(Left_Opnd
(N
)));
9047 Append_To
(Args
, Convert_To_Bignum
(Right_Opnd
(N
)));
9049 -- Now rewrite the arithmetic operator with a call to the
9050 -- corresponding bignum function.
9053 Make_Function_Call
(Loc
,
9054 Name
=> New_Occurrence_Of
(Fent
, Loc
),
9055 Parameter_Associations
=> Args
));
9056 Reanalyze
(RTE
(RE_Bignum
), Suppress
=> True);
9058 -- Indicate result is Bignum mode
9066 -- Otherwise we are in range of Long_Long_Integer, so no overflow
9067 -- check is required, at least not yet.
9070 Set_Do_Overflow_Check
(N
, False);
9073 -- Here we are not in Bignum territory, but we may have long long
9074 -- integer operands that need special handling. First a special check:
9075 -- If an exponentiation operator exponent is of type Long_Long_Integer,
9076 -- it means we converted it to prevent overflow, but exponentiation
9077 -- requires a Natural right operand, so convert it back to Natural.
9078 -- This conversion may raise an exception which is fine.
9080 if Nkind
(N
) = N_Op_Expon
and then Etype
(Right_Opnd
(N
)) = LLIB
then
9081 Convert_To_And_Rewrite
(Standard_Natural
, Right_Opnd
(N
));
9084 -- Here we will do the operation in Long_Long_Integer. We do this even
9085 -- if we know an overflow check is required, better to do this in long
9086 -- long integer mode, since we are less likely to overflow.
9088 -- Convert right or only operand to Long_Long_Integer, except that
9089 -- we do not touch the exponentiation right operand.
9091 if Nkind
(N
) /= N_Op_Expon
then
9092 Convert_To_And_Rewrite
(LLIB
, Right_Opnd
(N
));
9095 -- Convert left operand to Long_Long_Integer for binary case
9098 Convert_To_And_Rewrite
(LLIB
, Left_Opnd
(N
));
9101 -- Reset node to unanalyzed
9103 Set_Analyzed
(N
, False);
9104 Set_Etype
(N
, Empty
);
9105 Set_Entity
(N
, Empty
);
9107 -- Now analyze this new node. This reanalysis will complete processing
9108 -- for the node. In particular we will complete the expansion of an
9109 -- exponentiation operator (e.g. changing A ** 2 to A * A), and also
9110 -- we will complete any division checks (since we have not changed the
9111 -- setting of the Do_Division_Check flag).
9113 -- We do this reanalysis in STRICT mode to avoid recursion into the
9114 -- MINIMIZED/ELIMINATED handling, since we are now done with that.
9117 SG
: constant Overflow_Mode_Type
:=
9118 Scope_Suppress
.Overflow_Mode_General
;
9119 SA
: constant Overflow_Mode_Type
:=
9120 Scope_Suppress
.Overflow_Mode_Assertions
;
9123 Scope_Suppress
.Overflow_Mode_General
:= Strict
;
9124 Scope_Suppress
.Overflow_Mode_Assertions
:= Strict
;
9126 if not Do_Overflow_Check
(N
) then
9127 Reanalyze
(LLIB
, Suppress
=> True);
9132 Scope_Suppress
.Overflow_Mode_General
:= SG
;
9133 Scope_Suppress
.Overflow_Mode_Assertions
:= SA
;
9135 end Minimize_Eliminate_Overflows
;
9137 -------------------------
9138 -- Overflow_Check_Mode --
9139 -------------------------
9141 function Overflow_Check_Mode
return Overflow_Mode_Type
is
9143 if In_Assertion_Expr
= 0 then
9144 return Scope_Suppress
.Overflow_Mode_General
;
9146 return Scope_Suppress
.Overflow_Mode_Assertions
;
9148 end Overflow_Check_Mode
;
9150 --------------------------------
9151 -- Overflow_Checks_Suppressed --
9152 --------------------------------
9154 function Overflow_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
9156 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
9157 return Is_Check_Suppressed
(E
, Overflow_Check
);
9159 return Scope_Suppress
.Suppress
(Overflow_Check
);
9161 end Overflow_Checks_Suppressed
;
9163 ---------------------------------
9164 -- Predicate_Checks_Suppressed --
9165 ---------------------------------
9167 function Predicate_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
9169 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
9170 return Is_Check_Suppressed
(E
, Predicate_Check
);
9172 return Scope_Suppress
.Suppress
(Predicate_Check
);
9174 end Predicate_Checks_Suppressed
;
9176 -----------------------------
9177 -- Range_Checks_Suppressed --
9178 -----------------------------
9180 function Range_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
9183 if Kill_Range_Checks
(E
) then
9186 elsif Checks_May_Be_Suppressed
(E
) then
9187 return Is_Check_Suppressed
(E
, Range_Check
);
9191 return Scope_Suppress
.Suppress
(Range_Check
);
9192 end Range_Checks_Suppressed
;
9194 -----------------------------------------
9195 -- Range_Or_Validity_Checks_Suppressed --
9196 -----------------------------------------
9198 -- Note: the coding would be simpler here if we simply made appropriate
9199 -- calls to Range/Validity_Checks_Suppressed, but that would result in
9200 -- duplicated checks which we prefer to avoid.
9202 function Range_Or_Validity_Checks_Suppressed
9203 (Expr
: Node_Id
) return Boolean
9206 -- Immediate return if scope checks suppressed for either check
9208 if Scope_Suppress
.Suppress
(Range_Check
)
9210 Scope_Suppress
.Suppress
(Validity_Check
)
9215 -- If no expression, that's odd, decide that checks are suppressed,
9216 -- since we don't want anyone trying to do checks in this case, which
9217 -- is most likely the result of some other error.
9223 -- Expression is present, so perform suppress checks on type
9226 Typ
: constant Entity_Id
:= Etype
(Expr
);
9228 if Checks_May_Be_Suppressed
(Typ
)
9229 and then (Is_Check_Suppressed
(Typ
, Range_Check
)
9231 Is_Check_Suppressed
(Typ
, Validity_Check
))
9237 -- If expression is an entity name, perform checks on this entity
9239 if Is_Entity_Name
(Expr
) then
9241 Ent
: constant Entity_Id
:= Entity
(Expr
);
9243 if Checks_May_Be_Suppressed
(Ent
) then
9244 return Is_Check_Suppressed
(Ent
, Range_Check
)
9245 or else Is_Check_Suppressed
(Ent
, Validity_Check
);
9250 -- If we fall through, no checks suppressed
9253 end Range_Or_Validity_Checks_Suppressed
;
9259 procedure Remove_Checks
(Expr
: Node_Id
) is
9260 function Process
(N
: Node_Id
) return Traverse_Result
;
9261 -- Process a single node during the traversal
9263 procedure Traverse
is new Traverse_Proc
(Process
);
9264 -- The traversal procedure itself
9270 function Process
(N
: Node_Id
) return Traverse_Result
is
9272 if Nkind
(N
) not in N_Subexpr
then
9276 Set_Do_Range_Check
(N
, False);
9280 Traverse
(Left_Opnd
(N
));
9283 when N_Attribute_Reference
=>
9284 Set_Do_Overflow_Check
(N
, False);
9286 when N_Function_Call
=>
9287 Set_Do_Tag_Check
(N
, False);
9290 Set_Do_Overflow_Check
(N
, False);
9294 Set_Do_Division_Check
(N
, False);
9297 Set_Do_Length_Check
(N
, False);
9300 Set_Do_Division_Check
(N
, False);
9303 Set_Do_Length_Check
(N
, False);
9306 Set_Do_Division_Check
(N
, False);
9309 Set_Do_Length_Check
(N
, False);
9316 Traverse
(Left_Opnd
(N
));
9319 when N_Selected_Component
=>
9320 Set_Do_Discriminant_Check
(N
, False);
9322 when N_Type_Conversion
=>
9323 Set_Do_Length_Check
(N
, False);
9324 Set_Do_Tag_Check
(N
, False);
9325 Set_Do_Overflow_Check
(N
, False);
9334 -- Start of processing for Remove_Checks
9340 ----------------------------
9341 -- Selected_Length_Checks --
9342 ----------------------------
9344 function Selected_Length_Checks
9346 Target_Typ
: Entity_Id
;
9347 Source_Typ
: Entity_Id
;
9348 Warn_Node
: Node_Id
) return Check_Result
9350 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
9353 Expr_Actual
: Node_Id
;
9355 Cond
: Node_Id
:= Empty
;
9356 Do_Access
: Boolean := False;
9357 Wnode
: Node_Id
:= Warn_Node
;
9358 Ret_Result
: Check_Result
:= (Empty
, Empty
);
9359 Num_Checks
: Natural := 0;
9361 procedure Add_Check
(N
: Node_Id
);
9362 -- Adds the action given to Ret_Result if N is non-Empty
9364 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
;
9365 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
9366 -- Comments required ???
9368 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean;
9369 -- True for equal literals and for nodes that denote the same constant
9370 -- entity, even if its value is not a static constant. This includes the
9371 -- case of a discriminal reference within an init proc. Removes some
9372 -- obviously superfluous checks.
9374 function Length_E_Cond
9375 (Exptyp
: Entity_Id
;
9377 Indx
: Nat
) return Node_Id
;
9378 -- Returns expression to compute:
9379 -- Typ'Length /= Exptyp'Length
9381 function Length_N_Cond
9384 Indx
: Nat
) return Node_Id
;
9385 -- Returns expression to compute:
9386 -- Typ'Length /= Expr'Length
9392 procedure Add_Check
(N
: Node_Id
) is
9396 -- For now, ignore attempt to place more than two checks ???
9397 -- This is really worrisome, are we really discarding checks ???
9399 if Num_Checks
= 2 then
9403 pragma Assert
(Num_Checks
<= 1);
9404 Num_Checks
:= Num_Checks
+ 1;
9405 Ret_Result
(Num_Checks
) := N
;
9413 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
is
9414 SE
: constant Entity_Id
:= Scope
(E
);
9416 E1
: Entity_Id
:= E
;
9419 if Ekind
(Scope
(E
)) = E_Record_Type
9420 and then Has_Discriminants
(Scope
(E
))
9422 N
:= Build_Discriminal_Subtype_Of_Component
(E
);
9425 Insert_Action
(Ck_Node
, N
);
9426 E1
:= Defining_Identifier
(N
);
9430 if Ekind
(E1
) = E_String_Literal_Subtype
then
9432 Make_Integer_Literal
(Loc
,
9433 Intval
=> String_Literal_Length
(E1
));
9435 elsif SE
/= Standard_Standard
9436 and then Ekind
(Scope
(SE
)) = E_Protected_Type
9437 and then Has_Discriminants
(Scope
(SE
))
9438 and then Has_Completion
(Scope
(SE
))
9439 and then not Inside_Init_Proc
9441 -- If the type whose length is needed is a private component
9442 -- constrained by a discriminant, we must expand the 'Length
9443 -- attribute into an explicit computation, using the discriminal
9444 -- of the current protected operation. This is because the actual
9445 -- type of the prival is constructed after the protected opera-
9446 -- tion has been fully expanded.
9449 Indx_Type
: Node_Id
;
9452 Do_Expand
: Boolean := False;
9455 Indx_Type
:= First_Index
(E
);
9457 for J
in 1 .. Indx
- 1 loop
9458 Next_Index
(Indx_Type
);
9461 Get_Index_Bounds
(Indx_Type
, Lo
, Hi
);
9463 if Nkind
(Lo
) = N_Identifier
9464 and then Ekind
(Entity
(Lo
)) = E_In_Parameter
9466 Lo
:= Get_Discriminal
(E
, Lo
);
9470 if Nkind
(Hi
) = N_Identifier
9471 and then Ekind
(Entity
(Hi
)) = E_In_Parameter
9473 Hi
:= Get_Discriminal
(E
, Hi
);
9478 if not Is_Entity_Name
(Lo
) then
9479 Lo
:= Duplicate_Subexpr_No_Checks
(Lo
);
9482 if not Is_Entity_Name
(Hi
) then
9483 Lo
:= Duplicate_Subexpr_No_Checks
(Hi
);
9489 Make_Op_Subtract
(Loc
,
9493 Right_Opnd
=> Make_Integer_Literal
(Loc
, 1));
9498 Make_Attribute_Reference
(Loc
,
9499 Attribute_Name
=> Name_Length
,
9501 New_Occurrence_Of
(E1
, Loc
));
9504 Set_Expressions
(N
, New_List
(
9505 Make_Integer_Literal
(Loc
, Indx
)));
9514 Make_Attribute_Reference
(Loc
,
9515 Attribute_Name
=> Name_Length
,
9517 New_Occurrence_Of
(E1
, Loc
));
9520 Set_Expressions
(N
, New_List
(
9521 Make_Integer_Literal
(Loc
, Indx
)));
9532 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
9535 Make_Attribute_Reference
(Loc
,
9536 Attribute_Name
=> Name_Length
,
9538 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
9539 Expressions
=> New_List
(
9540 Make_Integer_Literal
(Loc
, Indx
)));
9547 function Length_E_Cond
9548 (Exptyp
: Entity_Id
;
9550 Indx
: Nat
) return Node_Id
9555 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
9556 Right_Opnd
=> Get_E_Length
(Exptyp
, Indx
));
9563 function Length_N_Cond
9566 Indx
: Nat
) return Node_Id
9571 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
9572 Right_Opnd
=> Get_N_Length
(Expr
, Indx
));
9579 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean is
9582 (Nkind
(L
) = N_Integer_Literal
9583 and then Nkind
(R
) = N_Integer_Literal
9584 and then Intval
(L
) = Intval
(R
))
9588 and then Ekind
(Entity
(L
)) = E_Constant
9589 and then ((Is_Entity_Name
(R
)
9590 and then Entity
(L
) = Entity
(R
))
9592 (Nkind
(R
) = N_Type_Conversion
9593 and then Is_Entity_Name
(Expression
(R
))
9594 and then Entity
(L
) = Entity
(Expression
(R
)))))
9598 and then Ekind
(Entity
(R
)) = E_Constant
9599 and then Nkind
(L
) = N_Type_Conversion
9600 and then Is_Entity_Name
(Expression
(L
))
9601 and then Entity
(R
) = Entity
(Expression
(L
)))
9605 and then Is_Entity_Name
(R
)
9606 and then Entity
(L
) = Entity
(R
)
9607 and then Ekind
(Entity
(L
)) = E_In_Parameter
9608 and then Inside_Init_Proc
);
9611 -- Start of processing for Selected_Length_Checks
9614 -- Checks will be applied only when generating code
9616 if not Expander_Active
then
9620 if Target_Typ
= Any_Type
9621 or else Target_Typ
= Any_Composite
9622 or else Raises_Constraint_Error
(Ck_Node
)
9631 T_Typ
:= Target_Typ
;
9633 if No
(Source_Typ
) then
9634 S_Typ
:= Etype
(Ck_Node
);
9636 S_Typ
:= Source_Typ
;
9639 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
9643 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
9644 S_Typ
:= Designated_Type
(S_Typ
);
9645 T_Typ
:= Designated_Type
(T_Typ
);
9648 -- A simple optimization for the null case
9650 if Known_Null
(Ck_Node
) then
9655 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
9656 if Is_Constrained
(T_Typ
) then
9658 -- The checking code to be generated will freeze the corresponding
9659 -- array type. However, we must freeze the type now, so that the
9660 -- freeze node does not appear within the generated if expression,
9663 Freeze_Before
(Ck_Node
, T_Typ
);
9665 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
9666 Exptyp
:= Get_Actual_Subtype
(Ck_Node
);
9668 if Is_Access_Type
(Exptyp
) then
9669 Exptyp
:= Designated_Type
(Exptyp
);
9672 -- String_Literal case. This needs to be handled specially be-
9673 -- cause no index types are available for string literals. The
9674 -- condition is simply:
9676 -- T_Typ'Length = string-literal-length
9678 if Nkind
(Expr_Actual
) = N_String_Literal
9679 and then Ekind
(Etype
(Expr_Actual
)) = E_String_Literal_Subtype
9683 Left_Opnd
=> Get_E_Length
(T_Typ
, 1),
9685 Make_Integer_Literal
(Loc
,
9687 String_Literal_Length
(Etype
(Expr_Actual
))));
9689 -- General array case. Here we have a usable actual subtype for
9690 -- the expression, and the condition is built from the two types
9693 -- T_Typ'Length /= Exptyp'Length or else
9694 -- T_Typ'Length (2) /= Exptyp'Length (2) or else
9695 -- T_Typ'Length (3) /= Exptyp'Length (3) or else
9698 elsif Is_Constrained
(Exptyp
) then
9700 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
9713 -- At the library level, we need to ensure that the type of
9714 -- the object is elaborated before the check itself is
9715 -- emitted. This is only done if the object is in the
9716 -- current compilation unit, otherwise the type is frozen
9717 -- and elaborated in its unit.
9719 if Is_Itype
(Exptyp
)
9721 Ekind
(Cunit_Entity
(Current_Sem_Unit
)) = E_Package
9723 not In_Package_Body
(Cunit_Entity
(Current_Sem_Unit
))
9724 and then In_Open_Scopes
(Scope
(Exptyp
))
9726 Ref_Node
:= Make_Itype_Reference
(Sloc
(Ck_Node
));
9727 Set_Itype
(Ref_Node
, Exptyp
);
9728 Insert_Action
(Ck_Node
, Ref_Node
);
9731 L_Index
:= First_Index
(T_Typ
);
9732 R_Index
:= First_Index
(Exptyp
);
9734 for Indx
in 1 .. Ndims
loop
9735 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
9737 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
9739 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
9740 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
9742 -- Deal with compile time length check. Note that we
9743 -- skip this in the access case, because the access
9744 -- value may be null, so we cannot know statically.
9747 and then Compile_Time_Known_Value
(L_Low
)
9748 and then Compile_Time_Known_Value
(L_High
)
9749 and then Compile_Time_Known_Value
(R_Low
)
9750 and then Compile_Time_Known_Value
(R_High
)
9752 if Expr_Value
(L_High
) >= Expr_Value
(L_Low
) then
9753 L_Length
:= Expr_Value
(L_High
) -
9754 Expr_Value
(L_Low
) + 1;
9756 L_Length
:= UI_From_Int
(0);
9759 if Expr_Value
(R_High
) >= Expr_Value
(R_Low
) then
9760 R_Length
:= Expr_Value
(R_High
) -
9761 Expr_Value
(R_Low
) + 1;
9763 R_Length
:= UI_From_Int
(0);
9766 if L_Length
> R_Length
then
9768 (Compile_Time_Constraint_Error
9769 (Wnode
, "too few elements for}??", T_Typ
));
9771 elsif L_Length
< R_Length
then
9773 (Compile_Time_Constraint_Error
9774 (Wnode
, "too many elements for}??", T_Typ
));
9777 -- The comparison for an individual index subtype
9778 -- is omitted if the corresponding index subtypes
9779 -- statically match, since the result is known to
9780 -- be true. Note that this test is worth while even
9781 -- though we do static evaluation, because non-static
9782 -- subtypes can statically match.
9785 Subtypes_Statically_Match
9786 (Etype
(L_Index
), Etype
(R_Index
))
9789 (Same_Bounds
(L_Low
, R_Low
)
9790 and then Same_Bounds
(L_High
, R_High
))
9793 (Cond
, Length_E_Cond
(Exptyp
, T_Typ
, Indx
));
9802 -- Handle cases where we do not get a usable actual subtype that
9803 -- is constrained. This happens for example in the function call
9804 -- and explicit dereference cases. In these cases, we have to get
9805 -- the length or range from the expression itself, making sure we
9806 -- do not evaluate it more than once.
9808 -- Here Ck_Node is the original expression, or more properly the
9809 -- result of applying Duplicate_Expr to the original tree, forcing
9810 -- the result to be a name.
9814 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
9817 -- Build the condition for the explicit dereference case
9819 for Indx
in 1 .. Ndims
loop
9821 (Cond
, Length_N_Cond
(Ck_Node
, T_Typ
, Indx
));
9828 -- Construct the test and insert into the tree
9830 if Present
(Cond
) then
9832 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
9836 (Make_Raise_Constraint_Error
(Loc
,
9838 Reason
=> CE_Length_Check_Failed
));
9842 end Selected_Length_Checks
;
9844 ---------------------------
9845 -- Selected_Range_Checks --
9846 ---------------------------
9848 function Selected_Range_Checks
9850 Target_Typ
: Entity_Id
;
9851 Source_Typ
: Entity_Id
;
9852 Warn_Node
: Node_Id
) return Check_Result
9854 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
9857 Expr_Actual
: Node_Id
;
9859 Cond
: Node_Id
:= Empty
;
9860 Do_Access
: Boolean := False;
9861 Wnode
: Node_Id
:= Warn_Node
;
9862 Ret_Result
: Check_Result
:= (Empty
, Empty
);
9863 Num_Checks
: Natural := 0;
9865 procedure Add_Check
(N
: Node_Id
);
9866 -- Adds the action given to Ret_Result if N is non-Empty
9868 function Discrete_Range_Cond
9870 Typ
: Entity_Id
) return Node_Id
;
9871 -- Returns expression to compute:
9872 -- Low_Bound (Expr) < Typ'First
9874 -- High_Bound (Expr) > Typ'Last
9876 function Discrete_Expr_Cond
9878 Typ
: Entity_Id
) return Node_Id
;
9879 -- Returns expression to compute:
9884 function Get_E_First_Or_Last
9888 Nam
: Name_Id
) return Node_Id
;
9889 -- Returns an attribute reference
9890 -- E'First or E'Last
9891 -- with a source location of Loc.
9893 -- Nam is Name_First or Name_Last, according to which attribute is
9894 -- desired. If Indx is non-zero, it is passed as a literal in the
9895 -- Expressions of the attribute reference (identifying the desired
9896 -- array dimension).
9898 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
9899 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
9900 -- Returns expression to compute:
9901 -- N'First or N'Last using Duplicate_Subexpr_No_Checks
9903 function Range_E_Cond
9904 (Exptyp
: Entity_Id
;
9908 -- Returns expression to compute:
9909 -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
9911 function Range_Equal_E_Cond
9912 (Exptyp
: Entity_Id
;
9914 Indx
: Nat
) return Node_Id
;
9915 -- Returns expression to compute:
9916 -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
9918 function Range_N_Cond
9921 Indx
: Nat
) return Node_Id
;
9922 -- Return expression to compute:
9923 -- Expr'First < Typ'First or else Expr'Last > Typ'Last
9929 procedure Add_Check
(N
: Node_Id
) is
9933 -- For now, ignore attempt to place more than 2 checks ???
9935 if Num_Checks
= 2 then
9939 pragma Assert
(Num_Checks
<= 1);
9940 Num_Checks
:= Num_Checks
+ 1;
9941 Ret_Result
(Num_Checks
) := N
;
9945 -------------------------
9946 -- Discrete_Expr_Cond --
9947 -------------------------
9949 function Discrete_Expr_Cond
9951 Typ
: Entity_Id
) return Node_Id
9959 Convert_To
(Base_Type
(Typ
),
9960 Duplicate_Subexpr_No_Checks
(Expr
)),
9962 Convert_To
(Base_Type
(Typ
),
9963 Get_E_First_Or_Last
(Loc
, Typ
, 0, Name_First
))),
9968 Convert_To
(Base_Type
(Typ
),
9969 Duplicate_Subexpr_No_Checks
(Expr
)),
9973 Get_E_First_Or_Last
(Loc
, Typ
, 0, Name_Last
))));
9974 end Discrete_Expr_Cond
;
9976 -------------------------
9977 -- Discrete_Range_Cond --
9978 -------------------------
9980 function Discrete_Range_Cond
9982 Typ
: Entity_Id
) return Node_Id
9984 LB
: Node_Id
:= Low_Bound
(Expr
);
9985 HB
: Node_Id
:= High_Bound
(Expr
);
9987 Left_Opnd
: Node_Id
;
9988 Right_Opnd
: Node_Id
;
9991 if Nkind
(LB
) = N_Identifier
9992 and then Ekind
(Entity
(LB
)) = E_Discriminant
9994 LB
:= New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
10001 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(LB
)),
10006 Get_E_First_Or_Last
(Loc
, Typ
, 0, Name_First
)));
10008 if Nkind
(HB
) = N_Identifier
10009 and then Ekind
(Entity
(HB
)) = E_Discriminant
10011 HB
:= New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
10018 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(HB
)),
10023 Get_E_First_Or_Last
(Loc
, Typ
, 0, Name_Last
)));
10025 return Make_Or_Else
(Loc
, Left_Opnd
, Right_Opnd
);
10026 end Discrete_Range_Cond
;
10028 -------------------------
10029 -- Get_E_First_Or_Last --
10030 -------------------------
10032 function Get_E_First_Or_Last
10036 Nam
: Name_Id
) return Node_Id
10041 Exprs
:= New_List
(Make_Integer_Literal
(Loc
, UI_From_Int
(Indx
)));
10046 return Make_Attribute_Reference
(Loc
,
10047 Prefix
=> New_Occurrence_Of
(E
, Loc
),
10048 Attribute_Name
=> Nam
,
10049 Expressions
=> Exprs
);
10050 end Get_E_First_Or_Last
;
10056 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
10059 Make_Attribute_Reference
(Loc
,
10060 Attribute_Name
=> Name_First
,
10062 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
10063 Expressions
=> New_List
(
10064 Make_Integer_Literal
(Loc
, Indx
)));
10071 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
10074 Make_Attribute_Reference
(Loc
,
10075 Attribute_Name
=> Name_Last
,
10077 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
10078 Expressions
=> New_List
(
10079 Make_Integer_Literal
(Loc
, Indx
)));
10086 function Range_E_Cond
10087 (Exptyp
: Entity_Id
;
10089 Indx
: Nat
) return Node_Id
10097 Get_E_First_Or_Last
(Loc
, Exptyp
, Indx
, Name_First
),
10099 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_First
)),
10104 Get_E_First_Or_Last
(Loc
, Exptyp
, Indx
, Name_Last
),
10106 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_Last
)));
10109 ------------------------
10110 -- Range_Equal_E_Cond --
10111 ------------------------
10113 function Range_Equal_E_Cond
10114 (Exptyp
: Entity_Id
;
10116 Indx
: Nat
) return Node_Id
10124 Get_E_First_Or_Last
(Loc
, Exptyp
, Indx
, Name_First
),
10126 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_First
)),
10131 Get_E_First_Or_Last
(Loc
, Exptyp
, Indx
, Name_Last
),
10133 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_Last
)));
10134 end Range_Equal_E_Cond
;
10140 function Range_N_Cond
10143 Indx
: Nat
) return Node_Id
10151 Get_N_First
(Expr
, Indx
),
10153 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_First
)),
10158 Get_N_Last
(Expr
, Indx
),
10160 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_Last
)));
10163 -- Start of processing for Selected_Range_Checks
10166 -- Checks will be applied only when generating code. In GNATprove mode,
10167 -- we do not apply the checks, but we still call Selected_Range_Checks
10168 -- to possibly issue errors on SPARK code when a run-time error can be
10169 -- detected at compile time.
10171 if not Expander_Active
and not GNATprove_Mode
then
10175 if Target_Typ
= Any_Type
10176 or else Target_Typ
= Any_Composite
10177 or else Raises_Constraint_Error
(Ck_Node
)
10186 T_Typ
:= Target_Typ
;
10188 if No
(Source_Typ
) then
10189 S_Typ
:= Etype
(Ck_Node
);
10191 S_Typ
:= Source_Typ
;
10194 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
10198 -- The order of evaluating T_Typ before S_Typ seems to be critical
10199 -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
10200 -- in, and since Node can be an N_Range node, it might be invalid.
10201 -- Should there be an assert check somewhere for taking the Etype of
10202 -- an N_Range node ???
10204 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
10205 S_Typ
:= Designated_Type
(S_Typ
);
10206 T_Typ
:= Designated_Type
(T_Typ
);
10209 -- A simple optimization for the null case
10211 if Known_Null
(Ck_Node
) then
10216 -- For an N_Range Node, check for a null range and then if not
10217 -- null generate a range check action.
10219 if Nkind
(Ck_Node
) = N_Range
then
10221 -- There's no point in checking a range against itself
10223 if Ck_Node
= Scalar_Range
(T_Typ
) then
10228 T_LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
10229 T_HB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
10230 Known_T_LB
: constant Boolean := Compile_Time_Known_Value
(T_LB
);
10231 Known_T_HB
: constant Boolean := Compile_Time_Known_Value
(T_HB
);
10233 LB
: Node_Id
:= Low_Bound
(Ck_Node
);
10234 HB
: Node_Id
:= High_Bound
(Ck_Node
);
10235 Known_LB
: Boolean := False;
10236 Known_HB
: Boolean := False;
10238 Null_Range
: Boolean;
10239 Out_Of_Range_L
: Boolean;
10240 Out_Of_Range_H
: Boolean;
10243 -- Compute what is known at compile time
10245 if Known_T_LB
and Known_T_HB
then
10246 if Compile_Time_Known_Value
(LB
) then
10249 -- There's no point in checking that a bound is within its
10250 -- own range so pretend that it is known in this case. First
10251 -- deal with low bound.
10253 elsif Ekind
(Etype
(LB
)) = E_Signed_Integer_Subtype
10254 and then Scalar_Range
(Etype
(LB
)) = Scalar_Range
(T_Typ
)
10260 -- Likewise for the high bound
10262 if Compile_Time_Known_Value
(HB
) then
10265 elsif Ekind
(Etype
(HB
)) = E_Signed_Integer_Subtype
10266 and then Scalar_Range
(Etype
(HB
)) = Scalar_Range
(T_Typ
)
10273 -- Check for case where everything is static and we can do the
10274 -- check at compile time. This is skipped if we have an access
10275 -- type, since the access value may be null.
10277 -- ??? This code can be improved since you only need to know that
10278 -- the two respective bounds (LB & T_LB or HB & T_HB) are known at
10279 -- compile time to emit pertinent messages.
10281 if Known_T_LB
and Known_T_HB
and Known_LB
and Known_HB
10284 -- Floating-point case
10286 if Is_Floating_Point_Type
(S_Typ
) then
10287 Null_Range
:= Expr_Value_R
(HB
) < Expr_Value_R
(LB
);
10289 (Expr_Value_R
(LB
) < Expr_Value_R
(T_LB
))
10291 (Expr_Value_R
(LB
) > Expr_Value_R
(T_HB
));
10294 (Expr_Value_R
(HB
) > Expr_Value_R
(T_HB
))
10296 (Expr_Value_R
(HB
) < Expr_Value_R
(T_LB
));
10298 -- Fixed or discrete type case
10301 Null_Range
:= Expr_Value
(HB
) < Expr_Value
(LB
);
10303 (Expr_Value
(LB
) < Expr_Value
(T_LB
))
10305 (Expr_Value
(LB
) > Expr_Value
(T_HB
));
10308 (Expr_Value
(HB
) > Expr_Value
(T_HB
))
10310 (Expr_Value
(HB
) < Expr_Value
(T_LB
));
10313 if not Null_Range
then
10314 if Out_Of_Range_L
then
10315 if No
(Warn_Node
) then
10317 (Compile_Time_Constraint_Error
10318 (Low_Bound
(Ck_Node
),
10319 "static value out of range of}??", T_Typ
));
10323 (Compile_Time_Constraint_Error
10325 "static range out of bounds of}??", T_Typ
));
10329 if Out_Of_Range_H
then
10330 if No
(Warn_Node
) then
10332 (Compile_Time_Constraint_Error
10333 (High_Bound
(Ck_Node
),
10334 "static value out of range of}??", T_Typ
));
10338 (Compile_Time_Constraint_Error
10340 "static range out of bounds of}??", T_Typ
));
10347 LB
: Node_Id
:= Low_Bound
(Ck_Node
);
10348 HB
: Node_Id
:= High_Bound
(Ck_Node
);
10351 -- If either bound is a discriminant and we are within the
10352 -- record declaration, it is a use of the discriminant in a
10353 -- constraint of a component, and nothing can be checked
10354 -- here. The check will be emitted within the init proc.
10355 -- Before then, the discriminal has no real meaning.
10356 -- Similarly, if the entity is a discriminal, there is no
10357 -- check to perform yet.
10359 -- The same holds within a discriminated synchronized type,
10360 -- where the discriminant may constrain a component or an
10363 if Nkind
(LB
) = N_Identifier
10364 and then Denotes_Discriminant
(LB
, True)
10366 if Current_Scope
= Scope
(Entity
(LB
))
10367 or else Is_Concurrent_Type
(Current_Scope
)
10368 or else Ekind
(Entity
(LB
)) /= E_Discriminant
10373 New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
10377 if Nkind
(HB
) = N_Identifier
10378 and then Denotes_Discriminant
(HB
, True)
10380 if Current_Scope
= Scope
(Entity
(HB
))
10381 or else Is_Concurrent_Type
(Current_Scope
)
10382 or else Ekind
(Entity
(HB
)) /= E_Discriminant
10387 New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
10391 Cond
:= Discrete_Range_Cond
(Ck_Node
, T_Typ
);
10392 Set_Paren_Count
(Cond
, 1);
10395 Make_And_Then
(Loc
,
10399 Convert_To
(Base_Type
(Etype
(HB
)),
10400 Duplicate_Subexpr_No_Checks
(HB
)),
10402 Convert_To
(Base_Type
(Etype
(LB
)),
10403 Duplicate_Subexpr_No_Checks
(LB
))),
10404 Right_Opnd
=> Cond
);
10409 elsif Is_Scalar_Type
(S_Typ
) then
10411 -- This somewhat duplicates what Apply_Scalar_Range_Check does,
10412 -- except the above simply sets a flag in the node and lets
10413 -- gigi generate the check base on the Etype of the expression.
10414 -- Sometimes, however we want to do a dynamic check against an
10415 -- arbitrary target type, so we do that here.
10417 if Ekind
(Base_Type
(S_Typ
)) /= Ekind
(Base_Type
(T_Typ
)) then
10418 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
10420 -- For literals, we can tell if the constraint error will be
10421 -- raised at compile time, so we never need a dynamic check, but
10422 -- if the exception will be raised, then post the usual warning,
10423 -- and replace the literal with a raise constraint error
10424 -- expression. As usual, skip this for access types
10426 elsif Compile_Time_Known_Value
(Ck_Node
) and then not Do_Access
then
10428 LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
10429 UB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
10431 Out_Of_Range
: Boolean;
10432 Static_Bounds
: constant Boolean :=
10433 Compile_Time_Known_Value
(LB
)
10434 and Compile_Time_Known_Value
(UB
);
10437 -- Following range tests should use Sem_Eval routine ???
10439 if Static_Bounds
then
10440 if Is_Floating_Point_Type
(S_Typ
) then
10442 (Expr_Value_R
(Ck_Node
) < Expr_Value_R
(LB
))
10444 (Expr_Value_R
(Ck_Node
) > Expr_Value_R
(UB
));
10446 -- Fixed or discrete type
10450 Expr_Value
(Ck_Node
) < Expr_Value
(LB
)
10452 Expr_Value
(Ck_Node
) > Expr_Value
(UB
);
10455 -- Bounds of the type are static and the literal is out of
10456 -- range so output a warning message.
10458 if Out_Of_Range
then
10459 if No
(Warn_Node
) then
10461 (Compile_Time_Constraint_Error
10463 "static value out of range of}??", T_Typ
));
10467 (Compile_Time_Constraint_Error
10469 "static value out of range of}??", T_Typ
));
10474 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
10478 -- Here for the case of a non-static expression, we need a runtime
10479 -- check unless the source type range is guaranteed to be in the
10480 -- range of the target type.
10483 if not In_Subrange_Of
(S_Typ
, T_Typ
) then
10484 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
10489 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
10490 if Is_Constrained
(T_Typ
) then
10492 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
10493 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
10495 if Is_Access_Type
(Exptyp
) then
10496 Exptyp
:= Designated_Type
(Exptyp
);
10499 -- String_Literal case. This needs to be handled specially be-
10500 -- cause no index types are available for string literals. The
10501 -- condition is simply:
10503 -- T_Typ'Length = string-literal-length
10505 if Nkind
(Expr_Actual
) = N_String_Literal
then
10508 -- General array case. Here we have a usable actual subtype for
10509 -- the expression, and the condition is built from the two types
10511 -- T_Typ'First < Exptyp'First or else
10512 -- T_Typ'Last > Exptyp'Last or else
10513 -- T_Typ'First(1) < Exptyp'First(1) or else
10514 -- T_Typ'Last(1) > Exptyp'Last(1) or else
10517 elsif Is_Constrained
(Exptyp
) then
10519 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
10525 L_Index
:= First_Index
(T_Typ
);
10526 R_Index
:= First_Index
(Exptyp
);
10528 for Indx
in 1 .. Ndims
loop
10529 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
10531 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
10533 -- Deal with compile time length check. Note that we
10534 -- skip this in the access case, because the access
10535 -- value may be null, so we cannot know statically.
10538 Subtypes_Statically_Match
10539 (Etype
(L_Index
), Etype
(R_Index
))
10541 -- If the target type is constrained then we
10542 -- have to check for exact equality of bounds
10543 -- (required for qualified expressions).
10545 if Is_Constrained
(T_Typ
) then
10548 Range_Equal_E_Cond
(Exptyp
, T_Typ
, Indx
));
10551 (Cond
, Range_E_Cond
(Exptyp
, T_Typ
, Indx
));
10561 -- Handle cases where we do not get a usable actual subtype that
10562 -- is constrained. This happens for example in the function call
10563 -- and explicit dereference cases. In these cases, we have to get
10564 -- the length or range from the expression itself, making sure we
10565 -- do not evaluate it more than once.
10567 -- Here Ck_Node is the original expression, or more properly the
10568 -- result of applying Duplicate_Expr to the original tree,
10569 -- forcing the result to be a name.
10573 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
10576 -- Build the condition for the explicit dereference case
10578 for Indx
in 1 .. Ndims
loop
10580 (Cond
, Range_N_Cond
(Ck_Node
, T_Typ
, Indx
));
10586 -- For a conversion to an unconstrained array type, generate an
10587 -- Action to check that the bounds of the source value are within
10588 -- the constraints imposed by the target type (RM 4.6(38)). No
10589 -- check is needed for a conversion to an access to unconstrained
10590 -- array type, as 4.6(24.15/2) requires the designated subtypes
10591 -- of the two access types to statically match.
10593 if Nkind
(Parent
(Ck_Node
)) = N_Type_Conversion
10594 and then not Do_Access
10597 Opnd_Index
: Node_Id
;
10598 Targ_Index
: Node_Id
;
10599 Opnd_Range
: Node_Id
;
10602 Opnd_Index
:= First_Index
(Get_Actual_Subtype
(Ck_Node
));
10603 Targ_Index
:= First_Index
(T_Typ
);
10604 while Present
(Opnd_Index
) loop
10606 -- If the index is a range, use its bounds. If it is an
10607 -- entity (as will be the case if it is a named subtype
10608 -- or an itype created for a slice) retrieve its range.
10610 if Is_Entity_Name
(Opnd_Index
)
10611 and then Is_Type
(Entity
(Opnd_Index
))
10613 Opnd_Range
:= Scalar_Range
(Entity
(Opnd_Index
));
10615 Opnd_Range
:= Opnd_Index
;
10618 if Nkind
(Opnd_Range
) = N_Range
then
10620 (Low_Bound
(Opnd_Range
), Etype
(Targ_Index
),
10621 Assume_Valid
=> True)
10624 (High_Bound
(Opnd_Range
), Etype
(Targ_Index
),
10625 Assume_Valid
=> True)
10629 -- If null range, no check needed
10632 Compile_Time_Known_Value
(High_Bound
(Opnd_Range
))
10634 Compile_Time_Known_Value
(Low_Bound
(Opnd_Range
))
10636 Expr_Value
(High_Bound
(Opnd_Range
)) <
10637 Expr_Value
(Low_Bound
(Opnd_Range
))
10641 elsif Is_Out_Of_Range
10642 (Low_Bound
(Opnd_Range
), Etype
(Targ_Index
),
10643 Assume_Valid
=> True)
10646 (High_Bound
(Opnd_Range
), Etype
(Targ_Index
),
10647 Assume_Valid
=> True)
10650 (Compile_Time_Constraint_Error
10651 (Wnode
, "value out of range of}??", T_Typ
));
10656 Discrete_Range_Cond
10657 (Opnd_Range
, Etype
(Targ_Index
)));
10661 Next_Index
(Opnd_Index
);
10662 Next_Index
(Targ_Index
);
10669 -- Construct the test and insert into the tree
10671 if Present
(Cond
) then
10673 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
10677 (Make_Raise_Constraint_Error
(Loc
,
10679 Reason
=> CE_Range_Check_Failed
));
10683 end Selected_Range_Checks
;
10685 -------------------------------
10686 -- Storage_Checks_Suppressed --
10687 -------------------------------
10689 function Storage_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
10691 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
10692 return Is_Check_Suppressed
(E
, Storage_Check
);
10694 return Scope_Suppress
.Suppress
(Storage_Check
);
10696 end Storage_Checks_Suppressed
;
10698 ---------------------------
10699 -- Tag_Checks_Suppressed --
10700 ---------------------------
10702 function Tag_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
10705 and then Checks_May_Be_Suppressed
(E
)
10707 return Is_Check_Suppressed
(E
, Tag_Check
);
10709 return Scope_Suppress
.Suppress
(Tag_Check
);
10711 end Tag_Checks_Suppressed
;
10713 ---------------------------------------
10714 -- Validate_Alignment_Check_Warnings --
10715 ---------------------------------------
10717 procedure Validate_Alignment_Check_Warnings
is
10719 for J
in Alignment_Warnings
.First
.. Alignment_Warnings
.Last
loop
10721 AWR
: Alignment_Warnings_Record
10722 renames Alignment_Warnings
.Table
(J
);
10724 if Known_Alignment
(AWR
.E
)
10725 and then AWR
.A
mod Alignment
(AWR
.E
) = 0
10727 Delete_Warning_And_Continuations
(AWR
.W
);
10731 end Validate_Alignment_Check_Warnings
;
10733 --------------------------
10734 -- Validity_Check_Range --
10735 --------------------------
10737 procedure Validity_Check_Range
10739 Related_Id
: Entity_Id
:= Empty
)
10742 if Validity_Checks_On
and Validity_Check_Operands
then
10743 if Nkind
(N
) = N_Range
then
10745 (Expr
=> Low_Bound
(N
),
10746 Related_Id
=> Related_Id
,
10747 Is_Low_Bound
=> True);
10750 (Expr
=> High_Bound
(N
),
10751 Related_Id
=> Related_Id
,
10752 Is_High_Bound
=> True);
10755 end Validity_Check_Range
;
10757 --------------------------------
10758 -- Validity_Checks_Suppressed --
10759 --------------------------------
10761 function Validity_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
10763 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
10764 return Is_Check_Suppressed
(E
, Validity_Check
);
10766 return Scope_Suppress
.Suppress
(Validity_Check
);
10768 end Validity_Checks_Suppressed
;