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
1891 if Is_Floating_Point_Type
(Etype
(N
)) then
1893 Make_Raise_Constraint_Error
(Loc
,
1896 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(Right
),
1897 Right_Opnd
=> Make_Real_Literal
(Loc
, Ureal_0
)),
1898 Reason
=> CE_Divide_By_Zero
));
1902 Make_Raise_Constraint_Error
(Loc
,
1905 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(Right
),
1906 Right_Opnd
=> Make_Integer_Literal
(Loc
, 0)),
1907 Reason
=> CE_Divide_By_Zero
));
1912 end Apply_Division_Check
;
1914 ----------------------------------
1915 -- Apply_Float_Conversion_Check --
1916 ----------------------------------
1918 -- Let F and I be the source and target types of the conversion. The RM
1919 -- specifies that a floating-point value X is rounded to the nearest
1920 -- integer, with halfway cases being rounded away from zero. The rounded
1921 -- value of X is checked against I'Range.
1923 -- The catch in the above paragraph is that there is no good way to know
1924 -- whether the round-to-integer operation resulted in overflow. A remedy is
1925 -- to perform a range check in the floating-point domain instead, however:
1927 -- (1) The bounds may not be known at compile time
1928 -- (2) The check must take into account rounding or truncation.
1929 -- (3) The range of type I may not be exactly representable in F.
1930 -- (4) For the rounding case, The end-points I'First - 0.5 and
1931 -- I'Last + 0.5 may or may not be in range, depending on the
1932 -- sign of I'First and I'Last.
1933 -- (5) X may be a NaN, which will fail any comparison
1935 -- The following steps correctly convert X with rounding:
1937 -- (1) If either I'First or I'Last is not known at compile time, use
1938 -- I'Base instead of I in the next three steps and perform a
1939 -- regular range check against I'Range after conversion.
1940 -- (2) If I'First - 0.5 is representable in F then let Lo be that
1941 -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be
1942 -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First).
1943 -- In other words, take one of the closest floating-point numbers
1944 -- (which is an integer value) to I'First, and see if it is in
1946 -- (3) If I'Last + 0.5 is representable in F then let Hi be that value
1947 -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be
1948 -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last).
1949 -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo)
1950 -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi)
1952 -- For the truncating case, replace steps (2) and (3) as follows:
1953 -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK
1954 -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let
1956 -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK
1957 -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let
1960 procedure Apply_Float_Conversion_Check
1962 Target_Typ
: Entity_Id
)
1964 LB
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1965 HB
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1966 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1967 Expr_Type
: constant Entity_Id
:= Base_Type
(Etype
(Ck_Node
));
1968 Target_Base
: constant Entity_Id
:=
1969 Implementation_Base_Type
(Target_Typ
);
1971 Par
: constant Node_Id
:= Parent
(Ck_Node
);
1972 pragma Assert
(Nkind
(Par
) = N_Type_Conversion
);
1973 -- Parent of check node, must be a type conversion
1975 Truncate
: constant Boolean := Float_Truncate
(Par
);
1976 Max_Bound
: constant Uint
:=
1978 (Machine_Radix_Value
(Expr_Type
),
1979 Machine_Mantissa_Value
(Expr_Type
) - 1) - 1;
1981 -- Largest bound, so bound plus or minus half is a machine number of F
1983 Ifirst
, Ilast
: Uint
;
1984 -- Bounds of integer type
1987 -- Bounds to check in floating-point domain
1989 Lo_OK
, Hi_OK
: Boolean;
1990 -- True iff Lo resp. Hi belongs to I'Range
1992 Lo_Chk
, Hi_Chk
: Node_Id
;
1993 -- Expressions that are False iff check fails
1995 Reason
: RT_Exception_Code
;
1998 -- We do not need checks if we are not generating code (i.e. the full
1999 -- expander is not active). In SPARK mode, we specifically don't want
2000 -- the frontend to expand these checks, which are dealt with directly
2001 -- in the formal verification backend.
2003 if not Expander_Active
then
2007 if not Compile_Time_Known_Value
(LB
)
2008 or not Compile_Time_Known_Value
(HB
)
2011 -- First check that the value falls in the range of the base type,
2012 -- to prevent overflow during conversion and then perform a
2013 -- regular range check against the (dynamic) bounds.
2015 pragma Assert
(Target_Base
/= Target_Typ
);
2017 Temp
: constant Entity_Id
:= Make_Temporary
(Loc
, 'T', Par
);
2020 Apply_Float_Conversion_Check
(Ck_Node
, Target_Base
);
2021 Set_Etype
(Temp
, Target_Base
);
2023 Insert_Action
(Parent
(Par
),
2024 Make_Object_Declaration
(Loc
,
2025 Defining_Identifier
=> Temp
,
2026 Object_Definition
=> New_Occurrence_Of
(Target_Typ
, Loc
),
2027 Expression
=> New_Copy_Tree
(Par
)),
2028 Suppress
=> All_Checks
);
2031 Make_Raise_Constraint_Error
(Loc
,
2034 Left_Opnd
=> New_Occurrence_Of
(Temp
, Loc
),
2035 Right_Opnd
=> New_Occurrence_Of
(Target_Typ
, Loc
)),
2036 Reason
=> CE_Range_Check_Failed
));
2037 Rewrite
(Par
, New_Occurrence_Of
(Temp
, Loc
));
2043 -- Get the (static) bounds of the target type
2045 Ifirst
:= Expr_Value
(LB
);
2046 Ilast
:= Expr_Value
(HB
);
2048 -- A simple optimization: if the expression is a universal literal,
2049 -- we can do the comparison with the bounds and the conversion to
2050 -- an integer type statically. The range checks are unchanged.
2052 if Nkind
(Ck_Node
) = N_Real_Literal
2053 and then Etype
(Ck_Node
) = Universal_Real
2054 and then Is_Integer_Type
(Target_Typ
)
2055 and then Nkind
(Parent
(Ck_Node
)) = N_Type_Conversion
2058 Int_Val
: constant Uint
:= UR_To_Uint
(Realval
(Ck_Node
));
2061 if Int_Val
<= Ilast
and then Int_Val
>= Ifirst
then
2063 -- Conversion is safe
2065 Rewrite
(Parent
(Ck_Node
),
2066 Make_Integer_Literal
(Loc
, UI_To_Int
(Int_Val
)));
2067 Analyze_And_Resolve
(Parent
(Ck_Node
), Target_Typ
);
2073 -- Check against lower bound
2075 if Truncate
and then Ifirst
> 0 then
2076 Lo
:= Pred
(Expr_Type
, UR_From_Uint
(Ifirst
));
2080 Lo
:= Succ
(Expr_Type
, UR_From_Uint
(Ifirst
- 1));
2083 elsif abs (Ifirst
) < Max_Bound
then
2084 Lo
:= UR_From_Uint
(Ifirst
) - Ureal_Half
;
2085 Lo_OK
:= (Ifirst
> 0);
2088 Lo
:= Machine
(Expr_Type
, UR_From_Uint
(Ifirst
), Round_Even
, Ck_Node
);
2089 Lo_OK
:= (Lo
>= UR_From_Uint
(Ifirst
));
2094 -- Lo_Chk := (X >= Lo)
2096 Lo_Chk
:= Make_Op_Ge
(Loc
,
2097 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
2098 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
2101 -- Lo_Chk := (X > Lo)
2103 Lo_Chk
:= Make_Op_Gt
(Loc
,
2104 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
2105 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
2108 -- Check against higher bound
2110 if Truncate
and then Ilast
< 0 then
2111 Hi
:= Succ
(Expr_Type
, UR_From_Uint
(Ilast
));
2115 Hi
:= Pred
(Expr_Type
, UR_From_Uint
(Ilast
+ 1));
2118 elsif abs (Ilast
) < Max_Bound
then
2119 Hi
:= UR_From_Uint
(Ilast
) + Ureal_Half
;
2120 Hi_OK
:= (Ilast
< 0);
2122 Hi
:= Machine
(Expr_Type
, UR_From_Uint
(Ilast
), Round_Even
, Ck_Node
);
2123 Hi_OK
:= (Hi
<= UR_From_Uint
(Ilast
));
2128 -- Hi_Chk := (X <= Hi)
2130 Hi_Chk
:= Make_Op_Le
(Loc
,
2131 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
2132 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
2135 -- Hi_Chk := (X < Hi)
2137 Hi_Chk
:= Make_Op_Lt
(Loc
,
2138 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
2139 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
2142 -- If the bounds of the target type are the same as those of the base
2143 -- type, the check is an overflow check as a range check is not
2144 -- performed in these cases.
2146 if Expr_Value
(Type_Low_Bound
(Target_Base
)) = Ifirst
2147 and then Expr_Value
(Type_High_Bound
(Target_Base
)) = Ilast
2149 Reason
:= CE_Overflow_Check_Failed
;
2151 Reason
:= CE_Range_Check_Failed
;
2154 -- Raise CE if either conditions does not hold
2156 Insert_Action
(Ck_Node
,
2157 Make_Raise_Constraint_Error
(Loc
,
2158 Condition
=> Make_Op_Not
(Loc
, Make_And_Then
(Loc
, Lo_Chk
, Hi_Chk
)),
2160 end Apply_Float_Conversion_Check
;
2162 ------------------------
2163 -- Apply_Length_Check --
2164 ------------------------
2166 procedure Apply_Length_Check
2168 Target_Typ
: Entity_Id
;
2169 Source_Typ
: Entity_Id
:= Empty
)
2172 Apply_Selected_Length_Checks
2173 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
2174 end Apply_Length_Check
;
2176 -------------------------------------
2177 -- Apply_Parameter_Aliasing_Checks --
2178 -------------------------------------
2180 procedure Apply_Parameter_Aliasing_Checks
2184 Loc
: constant Source_Ptr
:= Sloc
(Call
);
2186 function May_Cause_Aliasing
2187 (Formal_1
: Entity_Id
;
2188 Formal_2
: Entity_Id
) return Boolean;
2189 -- Determine whether two formal parameters can alias each other
2190 -- depending on their modes.
2192 function Original_Actual
(N
: Node_Id
) return Node_Id
;
2193 -- The expander may replace an actual with a temporary for the sake of
2194 -- side effect removal. The temporary may hide a potential aliasing as
2195 -- it does not share the address of the actual. This routine attempts
2196 -- to retrieve the original actual.
2198 procedure Overlap_Check
2199 (Actual_1
: Node_Id
;
2201 Formal_1
: Entity_Id
;
2202 Formal_2
: Entity_Id
;
2203 Check
: in out Node_Id
);
2204 -- Create a check to determine whether Actual_1 overlaps with Actual_2.
2205 -- If detailed exception messages are enabled, the check is augmented to
2206 -- provide information about the names of the corresponding formals. See
2207 -- the body for details. Actual_1 and Actual_2 denote the two actuals to
2208 -- be tested. Formal_1 and Formal_2 denote the corresponding formals.
2209 -- Check contains all and-ed simple tests generated so far or remains
2210 -- unchanged in the case of detailed exception messaged.
2212 ------------------------
2213 -- May_Cause_Aliasing --
2214 ------------------------
2216 function May_Cause_Aliasing
2217 (Formal_1
: Entity_Id
;
2218 Formal_2
: Entity_Id
) return Boolean
2221 -- The following combination cannot lead to aliasing
2223 -- Formal 1 Formal 2
2226 if Ekind
(Formal_1
) = E_In_Parameter
2228 Ekind
(Formal_2
) = E_In_Parameter
2232 -- The following combinations may lead to aliasing
2234 -- Formal 1 Formal 2
2244 end May_Cause_Aliasing
;
2246 ---------------------
2247 -- Original_Actual --
2248 ---------------------
2250 function Original_Actual
(N
: Node_Id
) return Node_Id
is
2252 if Nkind
(N
) = N_Type_Conversion
then
2253 return Expression
(N
);
2255 -- The expander created a temporary to capture the result of a type
2256 -- conversion where the expression is the real actual.
2258 elsif Nkind
(N
) = N_Identifier
2259 and then Present
(Original_Node
(N
))
2260 and then Nkind
(Original_Node
(N
)) = N_Type_Conversion
2262 return Expression
(Original_Node
(N
));
2266 end Original_Actual
;
2272 procedure Overlap_Check
2273 (Actual_1
: Node_Id
;
2275 Formal_1
: Entity_Id
;
2276 Formal_2
: Entity_Id
;
2277 Check
: in out Node_Id
)
2280 ID_Casing
: constant Casing_Type
:=
2281 Identifier_Casing
(Source_Index
(Current_Sem_Unit
));
2285 -- Actual_1'Overlaps_Storage (Actual_2)
2288 Make_Attribute_Reference
(Loc
,
2289 Prefix
=> New_Copy_Tree
(Original_Actual
(Actual_1
)),
2290 Attribute_Name
=> Name_Overlaps_Storage
,
2292 New_List
(New_Copy_Tree
(Original_Actual
(Actual_2
))));
2294 -- Generate the following check when detailed exception messages are
2297 -- if Actual_1'Overlaps_Storage (Actual_2) then
2298 -- raise Program_Error with <detailed message>;
2301 if Exception_Extra_Info
then
2304 -- Do not generate location information for internal calls
2306 if Comes_From_Source
(Call
) then
2307 Store_String_Chars
(Build_Location_String
(Loc
));
2308 Store_String_Char
(' ');
2311 Store_String_Chars
("aliased parameters, actuals for """);
2313 Get_Name_String
(Chars
(Formal_1
));
2314 Set_Casing
(ID_Casing
);
2315 Store_String_Chars
(Name_Buffer
(1 .. Name_Len
));
2317 Store_String_Chars
(""" and """);
2319 Get_Name_String
(Chars
(Formal_2
));
2320 Set_Casing
(ID_Casing
);
2321 Store_String_Chars
(Name_Buffer
(1 .. Name_Len
));
2323 Store_String_Chars
(""" overlap");
2325 Insert_Action
(Call
,
2326 Make_If_Statement
(Loc
,
2328 Then_Statements
=> New_List
(
2329 Make_Raise_Statement
(Loc
,
2331 New_Occurrence_Of
(Standard_Program_Error
, Loc
),
2332 Expression
=> Make_String_Literal
(Loc
, End_String
)))));
2334 -- Create a sequence of overlapping checks by and-ing them all
2344 Right_Opnd
=> Cond
);
2354 Formal_1
: Entity_Id
;
2355 Formal_2
: Entity_Id
;
2356 Orig_Act_1
: Node_Id
;
2357 Orig_Act_2
: Node_Id
;
2359 -- Start of processing for Apply_Parameter_Aliasing_Checks
2364 Actual_1
:= First_Actual
(Call
);
2365 Formal_1
:= First_Formal
(Subp
);
2366 while Present
(Actual_1
) and then Present
(Formal_1
) loop
2367 Orig_Act_1
:= Original_Actual
(Actual_1
);
2369 -- Ensure that the actual is an object that is not passed by value.
2370 -- Elementary types are always passed by value, therefore actuals of
2371 -- such types cannot lead to aliasing. An aggregate is an object in
2372 -- Ada 2012, but an actual that is an aggregate cannot overlap with
2373 -- another actual. A type that is By_Reference (such as an array of
2374 -- controlled types) is not subject to the check because any update
2375 -- will be done in place and a subsequent read will always see the
2376 -- correct value, see RM 6.2 (12/3).
2378 if Nkind
(Orig_Act_1
) = N_Aggregate
2379 or else (Nkind
(Orig_Act_1
) = N_Qualified_Expression
2380 and then Nkind
(Expression
(Orig_Act_1
)) = N_Aggregate
)
2384 elsif Is_Object_Reference
(Orig_Act_1
)
2385 and then not Is_Elementary_Type
(Etype
(Orig_Act_1
))
2386 and then not Is_By_Reference_Type
(Etype
(Orig_Act_1
))
2388 Actual_2
:= Next_Actual
(Actual_1
);
2389 Formal_2
:= Next_Formal
(Formal_1
);
2390 while Present
(Actual_2
) and then Present
(Formal_2
) loop
2391 Orig_Act_2
:= Original_Actual
(Actual_2
);
2393 -- The other actual we are testing against must also denote
2394 -- a non pass-by-value object. Generate the check only when
2395 -- the mode of the two formals may lead to aliasing.
2397 if Is_Object_Reference
(Orig_Act_2
)
2398 and then not Is_Elementary_Type
(Etype
(Orig_Act_2
))
2399 and then May_Cause_Aliasing
(Formal_1
, Formal_2
)
2401 Remove_Side_Effects
(Actual_1
);
2402 Remove_Side_Effects
(Actual_2
);
2405 (Actual_1
=> Actual_1
,
2406 Actual_2
=> Actual_2
,
2407 Formal_1
=> Formal_1
,
2408 Formal_2
=> Formal_2
,
2412 Next_Actual
(Actual_2
);
2413 Next_Formal
(Formal_2
);
2417 Next_Actual
(Actual_1
);
2418 Next_Formal
(Formal_1
);
2421 -- Place a simple check right before the call
2423 if Present
(Check
) and then not Exception_Extra_Info
then
2424 Insert_Action
(Call
,
2425 Make_Raise_Program_Error
(Loc
,
2427 Reason
=> PE_Aliased_Parameters
));
2429 end Apply_Parameter_Aliasing_Checks
;
2431 -------------------------------------
2432 -- Apply_Parameter_Validity_Checks --
2433 -------------------------------------
2435 procedure Apply_Parameter_Validity_Checks
(Subp
: Entity_Id
) is
2436 Subp_Decl
: Node_Id
;
2438 procedure Add_Validity_Check
2439 (Formal
: Entity_Id
;
2441 For_Result
: Boolean := False);
2442 -- Add a single 'Valid[_Scalar] check which verifies the initialization
2443 -- of Formal. Prag_Nam denotes the pre or post condition pragma name.
2444 -- Set flag For_Result when to verify the result of a function.
2446 ------------------------
2447 -- Add_Validity_Check --
2448 ------------------------
2450 procedure Add_Validity_Check
2451 (Formal
: Entity_Id
;
2453 For_Result
: Boolean := False)
2455 procedure Build_Pre_Post_Condition
(Expr
: Node_Id
);
2456 -- Create a pre/postcondition pragma that tests expression Expr
2458 ------------------------------
2459 -- Build_Pre_Post_Condition --
2460 ------------------------------
2462 procedure Build_Pre_Post_Condition
(Expr
: Node_Id
) is
2463 Loc
: constant Source_Ptr
:= Sloc
(Subp
);
2471 Pragma_Argument_Associations
=> New_List
(
2472 Make_Pragma_Argument_Association
(Loc
,
2473 Chars
=> Name_Check
,
2474 Expression
=> Expr
)));
2476 -- Add a message unless exception messages are suppressed
2478 if not Exception_Locations_Suppressed
then
2479 Append_To
(Pragma_Argument_Associations
(Prag
),
2480 Make_Pragma_Argument_Association
(Loc
,
2481 Chars
=> Name_Message
,
2483 Make_String_Literal
(Loc
,
2485 & Get_Name_String
(Prag_Nam
)
2487 & Build_Location_String
(Loc
))));
2490 -- Insert the pragma in the tree
2492 if Nkind
(Parent
(Subp_Decl
)) = N_Compilation_Unit
then
2493 Add_Global_Declaration
(Prag
);
2496 -- PPC pragmas associated with subprogram bodies must be inserted
2497 -- in the declarative part of the body.
2499 elsif Nkind
(Subp_Decl
) = N_Subprogram_Body
then
2500 Decls
:= Declarations
(Subp_Decl
);
2504 Set_Declarations
(Subp_Decl
, Decls
);
2507 Prepend_To
(Decls
, Prag
);
2510 -- For subprogram declarations insert the PPC pragma right after
2511 -- the declarative node.
2514 Insert_After_And_Analyze
(Subp_Decl
, Prag
);
2516 end Build_Pre_Post_Condition
;
2520 Loc
: constant Source_Ptr
:= Sloc
(Subp
);
2521 Typ
: constant Entity_Id
:= Etype
(Formal
);
2525 -- Start of processing for Add_Validity_Check
2528 -- For scalars, generate 'Valid test
2530 if Is_Scalar_Type
(Typ
) then
2533 -- For any non-scalar with scalar parts, generate 'Valid_Scalars test
2535 elsif Scalar_Part_Present
(Typ
) then
2536 Nam
:= Name_Valid_Scalars
;
2538 -- No test needed for other cases (no scalars to test)
2544 -- Step 1: Create the expression to verify the validity of the
2547 Check
:= New_Occurrence_Of
(Formal
, Loc
);
2549 -- When processing a function result, use 'Result. Generate
2554 Make_Attribute_Reference
(Loc
,
2556 Attribute_Name
=> Name_Result
);
2560 -- Context['Result]'Valid[_Scalars]
2563 Make_Attribute_Reference
(Loc
,
2565 Attribute_Name
=> Nam
);
2567 -- Step 2: Create a pre or post condition pragma
2569 Build_Pre_Post_Condition
(Check
);
2570 end Add_Validity_Check
;
2575 Subp_Spec
: Node_Id
;
2577 -- Start of processing for Apply_Parameter_Validity_Checks
2580 -- Extract the subprogram specification and declaration nodes
2582 Subp_Spec
:= Parent
(Subp
);
2584 if Nkind
(Subp_Spec
) = N_Defining_Program_Unit_Name
then
2585 Subp_Spec
:= Parent
(Subp_Spec
);
2588 Subp_Decl
:= Parent
(Subp_Spec
);
2590 if not Comes_From_Source
(Subp
)
2592 -- Do not process formal subprograms because the corresponding actual
2593 -- will receive the proper checks when the instance is analyzed.
2595 or else Is_Formal_Subprogram
(Subp
)
2597 -- Do not process imported subprograms since pre and postconditions
2598 -- are never verified on routines coming from a different language.
2600 or else Is_Imported
(Subp
)
2601 or else Is_Intrinsic_Subprogram
(Subp
)
2603 -- The PPC pragmas generated by this routine do not correspond to
2604 -- source aspects, therefore they cannot be applied to abstract
2607 or else Nkind
(Subp_Decl
) = N_Abstract_Subprogram_Declaration
2609 -- Do not consider subprogram renaminds because the renamed entity
2610 -- already has the proper PPC pragmas.
2612 or else Nkind
(Subp_Decl
) = N_Subprogram_Renaming_Declaration
2614 -- Do not process null procedures because there is no benefit of
2615 -- adding the checks to a no action routine.
2617 or else (Nkind
(Subp_Spec
) = N_Procedure_Specification
2618 and then Null_Present
(Subp_Spec
))
2623 -- Inspect all the formals applying aliasing and scalar initialization
2624 -- checks where applicable.
2626 Formal
:= First_Formal
(Subp
);
2627 while Present
(Formal
) loop
2629 -- Generate the following scalar initialization checks for each
2630 -- formal parameter:
2632 -- mode IN - Pre => Formal'Valid[_Scalars]
2633 -- mode IN OUT - Pre, Post => Formal'Valid[_Scalars]
2634 -- mode OUT - Post => Formal'Valid[_Scalars]
2636 if Check_Validity_Of_Parameters
then
2637 if Ekind_In
(Formal
, E_In_Parameter
, E_In_Out_Parameter
) then
2638 Add_Validity_Check
(Formal
, Name_Precondition
, False);
2641 if Ekind_In
(Formal
, E_In_Out_Parameter
, E_Out_Parameter
) then
2642 Add_Validity_Check
(Formal
, Name_Postcondition
, False);
2646 Next_Formal
(Formal
);
2649 -- Generate following scalar initialization check for function result:
2651 -- Post => Subp'Result'Valid[_Scalars]
2653 if Check_Validity_Of_Parameters
and then Ekind
(Subp
) = E_Function
then
2654 Add_Validity_Check
(Subp
, Name_Postcondition
, True);
2656 end Apply_Parameter_Validity_Checks
;
2658 ---------------------------
2659 -- Apply_Predicate_Check --
2660 ---------------------------
2662 procedure Apply_Predicate_Check
2665 Fun
: Entity_Id
:= Empty
)
2670 if Predicate_Checks_Suppressed
(Empty
) then
2673 elsif Predicates_Ignored
(Typ
) then
2676 elsif Present
(Predicate_Function
(Typ
)) then
2678 while Present
(S
) and then not Is_Subprogram
(S
) loop
2682 -- A predicate check does not apply within internally generated
2683 -- subprograms, such as TSS functions.
2685 if Within_Internal_Subprogram
then
2688 -- If the check appears within the predicate function itself, it
2689 -- means that the user specified a check whose formal is the
2690 -- predicated subtype itself, rather than some covering type. This
2691 -- is likely to be a common error, and thus deserves a warning.
2693 elsif Present
(S
) and then S
= Predicate_Function
(Typ
) then
2695 ("predicate check includes a call to& that requires a "
2696 & "predicate check??", Parent
(N
), Fun
);
2698 ("\this will result in infinite recursion??", Parent
(N
));
2700 if Is_First_Subtype
(Typ
) then
2702 ("\use an explicit subtype of& to carry the predicate",
2707 Make_Raise_Storage_Error
(Sloc
(N
),
2708 Reason
=> SE_Infinite_Recursion
));
2710 -- Here for normal case of predicate active
2713 -- If the type has a static predicate and the expression is known
2714 -- at compile time, see if the expression satisfies the predicate.
2716 Check_Expression_Against_Static_Predicate
(N
, Typ
);
2718 if not Expander_Active
then
2722 -- For an entity of the type, generate a call to the predicate
2723 -- function, unless its type is an actual subtype, which is not
2724 -- visible outside of the enclosing subprogram.
2726 if Is_Entity_Name
(N
)
2727 and then not Is_Actual_Subtype
(Typ
)
2730 Make_Predicate_Check
2731 (Typ
, New_Occurrence_Of
(Entity
(N
), Sloc
(N
))));
2733 -- If the expression is not an entity it may have side effects,
2734 -- and the following call will create an object declaration for
2735 -- it. We disable checks during its analysis, to prevent an
2736 -- infinite recursion.
2738 -- If the prefix is an aggregate in an assignment, apply the
2739 -- check to the LHS after assignment, rather than create a
2740 -- redundant temporary. This is only necessary in rare cases
2741 -- of array types (including strings) initialized with an
2742 -- aggregate with an "others" clause, either coming from source
2743 -- or generated by an Initialize_Scalars pragma.
2745 elsif Nkind
(N
) = N_Aggregate
2746 and then Nkind
(Parent
(N
)) = N_Assignment_Statement
2748 Insert_Action_After
(Parent
(N
),
2749 Make_Predicate_Check
2750 (Typ
, Duplicate_Subexpr
(Name
(Parent
(N
)))));
2754 Make_Predicate_Check
2755 (Typ
, Duplicate_Subexpr
(N
)), Suppress
=> All_Checks
);
2759 end Apply_Predicate_Check
;
2761 -----------------------
2762 -- Apply_Range_Check --
2763 -----------------------
2765 procedure Apply_Range_Check
2767 Target_Typ
: Entity_Id
;
2768 Source_Typ
: Entity_Id
:= Empty
)
2771 Apply_Selected_Range_Checks
2772 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
2773 end Apply_Range_Check
;
2775 ------------------------------
2776 -- Apply_Scalar_Range_Check --
2777 ------------------------------
2779 -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag
2780 -- off if it is already set on.
2782 procedure Apply_Scalar_Range_Check
2784 Target_Typ
: Entity_Id
;
2785 Source_Typ
: Entity_Id
:= Empty
;
2786 Fixed_Int
: Boolean := False)
2788 Parnt
: constant Node_Id
:= Parent
(Expr
);
2790 Arr
: Node_Id
:= Empty
; -- initialize to prevent warning
2791 Arr_Typ
: Entity_Id
:= Empty
; -- initialize to prevent warning
2793 Is_Subscr_Ref
: Boolean;
2794 -- Set true if Expr is a subscript
2796 Is_Unconstrained_Subscr_Ref
: Boolean;
2797 -- Set true if Expr is a subscript of an unconstrained array. In this
2798 -- case we do not attempt to do an analysis of the value against the
2799 -- range of the subscript, since we don't know the actual subtype.
2802 -- Set to True if Expr should be regarded as a real value even though
2803 -- the type of Expr might be discrete.
2805 procedure Bad_Value
(Warn
: Boolean := False);
2806 -- Procedure called if value is determined to be out of range. Warn is
2807 -- True to force a warning instead of an error, even when SPARK_Mode is
2814 procedure Bad_Value
(Warn
: Boolean := False) is
2816 Apply_Compile_Time_Constraint_Error
2817 (Expr
, "value not in range of}??", CE_Range_Check_Failed
,
2823 -- Start of processing for Apply_Scalar_Range_Check
2826 -- Return if check obviously not needed
2829 -- Not needed inside generic
2833 -- Not needed if previous error
2835 or else Target_Typ
= Any_Type
2836 or else Nkind
(Expr
) = N_Error
2838 -- Not needed for non-scalar type
2840 or else not Is_Scalar_Type
(Target_Typ
)
2842 -- Not needed if we know node raises CE already
2844 or else Raises_Constraint_Error
(Expr
)
2849 -- Now, see if checks are suppressed
2852 Is_List_Member
(Expr
) and then Nkind
(Parnt
) = N_Indexed_Component
;
2854 if Is_Subscr_Ref
then
2855 Arr
:= Prefix
(Parnt
);
2856 Arr_Typ
:= Get_Actual_Subtype_If_Available
(Arr
);
2858 if Is_Access_Type
(Arr_Typ
) then
2859 Arr_Typ
:= Designated_Type
(Arr_Typ
);
2863 if not Do_Range_Check
(Expr
) then
2865 -- Subscript reference. Check for Index_Checks suppressed
2867 if Is_Subscr_Ref
then
2869 -- Check array type and its base type
2871 if Index_Checks_Suppressed
(Arr_Typ
)
2872 or else Index_Checks_Suppressed
(Base_Type
(Arr_Typ
))
2876 -- Check array itself if it is an entity name
2878 elsif Is_Entity_Name
(Arr
)
2879 and then Index_Checks_Suppressed
(Entity
(Arr
))
2883 -- Check expression itself if it is an entity name
2885 elsif Is_Entity_Name
(Expr
)
2886 and then Index_Checks_Suppressed
(Entity
(Expr
))
2891 -- All other cases, check for Range_Checks suppressed
2894 -- Check target type and its base type
2896 if Range_Checks_Suppressed
(Target_Typ
)
2897 or else Range_Checks_Suppressed
(Base_Type
(Target_Typ
))
2901 -- Check expression itself if it is an entity name
2903 elsif Is_Entity_Name
(Expr
)
2904 and then Range_Checks_Suppressed
(Entity
(Expr
))
2908 -- If Expr is part of an assignment statement, then check left
2909 -- side of assignment if it is an entity name.
2911 elsif Nkind
(Parnt
) = N_Assignment_Statement
2912 and then Is_Entity_Name
(Name
(Parnt
))
2913 and then Range_Checks_Suppressed
(Entity
(Name
(Parnt
)))
2920 -- Do not set range checks if they are killed
2922 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
2923 and then Kill_Range_Check
(Expr
)
2928 -- Do not set range checks for any values from System.Scalar_Values
2929 -- since the whole idea of such values is to avoid checking them.
2931 if Is_Entity_Name
(Expr
)
2932 and then Is_RTU
(Scope
(Entity
(Expr
)), System_Scalar_Values
)
2937 -- Now see if we need a check
2939 if No
(Source_Typ
) then
2940 S_Typ
:= Etype
(Expr
);
2942 S_Typ
:= Source_Typ
;
2945 if not Is_Scalar_Type
(S_Typ
) or else S_Typ
= Any_Type
then
2949 Is_Unconstrained_Subscr_Ref
:=
2950 Is_Subscr_Ref
and then not Is_Constrained
(Arr_Typ
);
2952 -- Special checks for floating-point type
2954 if Is_Floating_Point_Type
(S_Typ
) then
2956 -- Always do a range check if the source type includes infinities and
2957 -- the target type does not include infinities. We do not do this if
2958 -- range checks are killed.
2959 -- If the expression is a literal and the bounds of the type are
2960 -- static constants it may be possible to optimize the check.
2962 if Has_Infinities
(S_Typ
)
2963 and then not Has_Infinities
(Target_Typ
)
2965 -- If the expression is a literal and the bounds of the type are
2966 -- static constants it may be possible to optimize the check.
2968 if Nkind
(Expr
) = N_Real_Literal
then
2970 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
2971 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
2974 if Compile_Time_Known_Value
(Tlo
)
2975 and then Compile_Time_Known_Value
(Thi
)
2976 and then Expr_Value_R
(Expr
) >= Expr_Value_R
(Tlo
)
2977 and then Expr_Value_R
(Expr
) <= Expr_Value_R
(Thi
)
2981 Enable_Range_Check
(Expr
);
2986 Enable_Range_Check
(Expr
);
2991 -- Return if we know expression is definitely in the range of the target
2992 -- type as determined by Determine_Range. Right now we only do this for
2993 -- discrete types, and not fixed-point or floating-point types.
2995 -- The additional less-precise tests below catch these cases
2997 -- In GNATprove_Mode, also deal with the case of a conversion from
2998 -- floating-point to integer. It is only possible because analysis
2999 -- in GNATprove rules out the possibility of a NaN or infinite value.
3001 -- Note: skip this if we are given a source_typ, since the point of
3002 -- supplying a Source_Typ is to stop us looking at the expression.
3003 -- We could sharpen this test to be out parameters only ???
3005 if Is_Discrete_Type
(Target_Typ
)
3006 and then (Is_Discrete_Type
(Etype
(Expr
))
3007 or else (GNATprove_Mode
3008 and then Is_Floating_Point_Type
(Etype
(Expr
))))
3009 and then not Is_Unconstrained_Subscr_Ref
3010 and then No
(Source_Typ
)
3013 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
3014 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
3017 if Compile_Time_Known_Value
(Tlo
)
3018 and then Compile_Time_Known_Value
(Thi
)
3021 OK
: Boolean := False; -- initialize to prevent warning
3022 Hiv
: constant Uint
:= Expr_Value
(Thi
);
3023 Lov
: constant Uint
:= Expr_Value
(Tlo
);
3024 Hi
: Uint
:= No_Uint
;
3025 Lo
: Uint
:= No_Uint
;
3028 -- If range is null, we for sure have a constraint error (we
3029 -- don't even need to look at the value involved, since all
3030 -- possible values will raise CE).
3034 -- When SPARK_Mode is On, force a warning instead of
3035 -- an error in that case, as this likely corresponds
3036 -- to deactivated code.
3038 Bad_Value
(Warn
=> SPARK_Mode
= On
);
3040 -- In GNATprove mode, we enable the range check so that
3041 -- GNATprove will issue a message if it cannot be proved.
3043 if GNATprove_Mode
then
3044 Enable_Range_Check
(Expr
);
3050 -- Otherwise determine range of value
3052 if Is_Discrete_Type
(Etype
(Expr
)) then
3054 (Expr
, OK
, Lo
, Hi
, Assume_Valid
=> True);
3056 -- When converting a float to an integer type, determine the
3057 -- range in real first, and then convert the bounds using
3058 -- UR_To_Uint which correctly rounds away from zero when
3059 -- half way between two integers, as required by normal
3060 -- Ada 95 rounding semantics. It is only possible because
3061 -- analysis in GNATprove rules out the possibility of a NaN
3062 -- or infinite value.
3064 elsif GNATprove_Mode
3065 and then Is_Floating_Point_Type
(Etype
(Expr
))
3073 (Expr
, OK
, Lor
, Hir
, Assume_Valid
=> True);
3076 Lo
:= UR_To_Uint
(Lor
);
3077 Hi
:= UR_To_Uint
(Hir
);
3084 -- If definitely in range, all OK
3086 if Lo
>= Lov
and then Hi
<= Hiv
then
3089 -- If definitely not in range, warn
3091 elsif Lov
> Hi
or else Hiv
< Lo
then
3093 -- Ignore out of range values for System.Priority in
3094 -- CodePeer mode since the actual target compiler may
3095 -- provide a wider range.
3097 if not CodePeer_Mode
3098 or else Target_Typ
/= RTE
(RE_Priority
)
3105 -- Otherwise we don't know
3117 Is_Floating_Point_Type
(S_Typ
)
3118 or else (Is_Fixed_Point_Type
(S_Typ
) and then not Fixed_Int
);
3120 -- Check if we can determine at compile time whether Expr is in the
3121 -- range of the target type. Note that if S_Typ is within the bounds
3122 -- of Target_Typ then this must be the case. This check is meaningful
3123 -- only if this is not a conversion between integer and real types.
3125 if not Is_Unconstrained_Subscr_Ref
3126 and then Is_Discrete_Type
(S_Typ
) = Is_Discrete_Type
(Target_Typ
)
3128 (In_Subrange_Of
(S_Typ
, Target_Typ
, Fixed_Int
)
3130 -- Also check if the expression itself is in the range of the
3131 -- target type if it is a known at compile time value. We skip
3132 -- this test if S_Typ is set since for OUT and IN OUT parameters
3133 -- the Expr itself is not relevant to the checking.
3137 and then Is_In_Range
(Expr
, Target_Typ
,
3138 Assume_Valid
=> True,
3139 Fixed_Int
=> Fixed_Int
,
3140 Int_Real
=> Int_Real
)))
3144 elsif Is_Out_Of_Range
(Expr
, Target_Typ
,
3145 Assume_Valid
=> True,
3146 Fixed_Int
=> Fixed_Int
,
3147 Int_Real
=> Int_Real
)
3152 -- Floating-point case
3153 -- In the floating-point case, we only do range checks if the type is
3154 -- constrained. We definitely do NOT want range checks for unconstrained
3155 -- types, since we want to have infinities, except when
3156 -- Check_Float_Overflow is set.
3158 elsif Is_Floating_Point_Type
(S_Typ
) then
3159 if Is_Constrained
(S_Typ
) or else Check_Float_Overflow
then
3160 Enable_Range_Check
(Expr
);
3163 -- For all other cases we enable a range check unconditionally
3166 Enable_Range_Check
(Expr
);
3169 end Apply_Scalar_Range_Check
;
3171 ----------------------------------
3172 -- Apply_Selected_Length_Checks --
3173 ----------------------------------
3175 procedure Apply_Selected_Length_Checks
3177 Target_Typ
: Entity_Id
;
3178 Source_Typ
: Entity_Id
;
3179 Do_Static
: Boolean)
3181 Checks_On
: constant Boolean :=
3182 not Index_Checks_Suppressed
(Target_Typ
)
3184 not Length_Checks_Suppressed
(Target_Typ
);
3186 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
3190 R_Result
: Check_Result
;
3193 -- Only apply checks when generating code
3195 -- Note: this means that we lose some useful warnings if the expander
3198 if not Expander_Active
then
3203 Selected_Length_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
3205 for J
in 1 .. 2 loop
3206 R_Cno
:= R_Result
(J
);
3207 exit when No
(R_Cno
);
3209 -- A length check may mention an Itype which is attached to a
3210 -- subsequent node. At the top level in a package this can cause
3211 -- an order-of-elaboration problem, so we make sure that the itype
3212 -- is referenced now.
3214 if Ekind
(Current_Scope
) = E_Package
3215 and then Is_Compilation_Unit
(Current_Scope
)
3217 Ensure_Defined
(Target_Typ
, Ck_Node
);
3219 if Present
(Source_Typ
) then
3220 Ensure_Defined
(Source_Typ
, Ck_Node
);
3222 elsif Is_Itype
(Etype
(Ck_Node
)) then
3223 Ensure_Defined
(Etype
(Ck_Node
), Ck_Node
);
3227 -- If the item is a conditional raise of constraint error, then have
3228 -- a look at what check is being performed and ???
3230 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
3231 and then Present
(Condition
(R_Cno
))
3233 Cond
:= Condition
(R_Cno
);
3235 -- Case where node does not now have a dynamic check
3237 if not Has_Dynamic_Length_Check
(Ck_Node
) then
3239 -- If checks are on, just insert the check
3242 Insert_Action
(Ck_Node
, R_Cno
);
3244 if not Do_Static
then
3245 Set_Has_Dynamic_Length_Check
(Ck_Node
);
3248 -- If checks are off, then analyze the length check after
3249 -- temporarily attaching it to the tree in case the relevant
3250 -- condition can be evaluated at compile time. We still want a
3251 -- compile time warning in this case.
3254 Set_Parent
(R_Cno
, Ck_Node
);
3259 -- Output a warning if the condition is known to be True
3261 if Is_Entity_Name
(Cond
)
3262 and then Entity
(Cond
) = Standard_True
3264 Apply_Compile_Time_Constraint_Error
3265 (Ck_Node
, "wrong length for array of}??",
3266 CE_Length_Check_Failed
,
3270 -- If we were only doing a static check, or if checks are not
3271 -- on, then we want to delete the check, since it is not needed.
3272 -- We do this by replacing the if statement by a null statement
3274 elsif Do_Static
or else not Checks_On
then
3275 Remove_Warning_Messages
(R_Cno
);
3276 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
3280 Install_Static_Check
(R_Cno
, Loc
);
3283 end Apply_Selected_Length_Checks
;
3285 ---------------------------------
3286 -- Apply_Selected_Range_Checks --
3287 ---------------------------------
3289 procedure Apply_Selected_Range_Checks
3291 Target_Typ
: Entity_Id
;
3292 Source_Typ
: Entity_Id
;
3293 Do_Static
: Boolean)
3295 Checks_On
: constant Boolean :=
3296 not Index_Checks_Suppressed
(Target_Typ
)
3298 not Range_Checks_Suppressed
(Target_Typ
);
3300 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
3304 R_Result
: Check_Result
;
3307 -- Only apply checks when generating code. In GNATprove mode, we do not
3308 -- apply the checks, but we still call Selected_Range_Checks to possibly
3309 -- issue errors on SPARK code when a run-time error can be detected at
3312 if not GNATprove_Mode
then
3313 if not Expander_Active
or not Checks_On
then
3319 Selected_Range_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
3321 if GNATprove_Mode
then
3325 for J
in 1 .. 2 loop
3326 R_Cno
:= R_Result
(J
);
3327 exit when No
(R_Cno
);
3329 -- The range check requires runtime evaluation. Depending on what its
3330 -- triggering condition is, the check may be converted into a compile
3331 -- time constraint check.
3333 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
3334 and then Present
(Condition
(R_Cno
))
3336 Cond
:= Condition
(R_Cno
);
3338 -- Insert the range check before the related context. Note that
3339 -- this action analyses the triggering condition.
3341 Insert_Action
(Ck_Node
, R_Cno
);
3343 -- This old code doesn't make sense, why is the context flagged as
3344 -- requiring dynamic range checks now in the middle of generating
3347 if not Do_Static
then
3348 Set_Has_Dynamic_Range_Check
(Ck_Node
);
3351 -- The triggering condition evaluates to True, the range check
3352 -- can be converted into a compile time constraint check.
3354 if Is_Entity_Name
(Cond
)
3355 and then Entity
(Cond
) = Standard_True
3357 -- Since an N_Range is technically not an expression, we have
3358 -- to set one of the bounds to C_E and then just flag the
3359 -- N_Range. The warning message will point to the lower bound
3360 -- and complain about a range, which seems OK.
3362 if Nkind
(Ck_Node
) = N_Range
then
3363 Apply_Compile_Time_Constraint_Error
3364 (Low_Bound
(Ck_Node
),
3365 "static range out of bounds of}??",
3366 CE_Range_Check_Failed
,
3370 Set_Raises_Constraint_Error
(Ck_Node
);
3373 Apply_Compile_Time_Constraint_Error
3375 "static value out of range of}??",
3376 CE_Range_Check_Failed
,
3381 -- If we were only doing a static check, or if checks are not
3382 -- on, then we want to delete the check, since it is not needed.
3383 -- We do this by replacing the if statement by a null statement
3385 elsif Do_Static
then
3386 Remove_Warning_Messages
(R_Cno
);
3387 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
3390 -- The range check raises Constraint_Error explicitly
3393 Install_Static_Check
(R_Cno
, Loc
);
3396 end Apply_Selected_Range_Checks
;
3398 -------------------------------
3399 -- Apply_Static_Length_Check --
3400 -------------------------------
3402 procedure Apply_Static_Length_Check
3404 Target_Typ
: Entity_Id
;
3405 Source_Typ
: Entity_Id
:= Empty
)
3408 Apply_Selected_Length_Checks
3409 (Expr
, Target_Typ
, Source_Typ
, Do_Static
=> True);
3410 end Apply_Static_Length_Check
;
3412 -------------------------------------
3413 -- Apply_Subscript_Validity_Checks --
3414 -------------------------------------
3416 procedure Apply_Subscript_Validity_Checks
(Expr
: Node_Id
) is
3420 pragma Assert
(Nkind
(Expr
) = N_Indexed_Component
);
3422 -- Loop through subscripts
3424 Sub
:= First
(Expressions
(Expr
));
3425 while Present
(Sub
) loop
3427 -- Check one subscript. Note that we do not worry about enumeration
3428 -- type with holes, since we will convert the value to a Pos value
3429 -- for the subscript, and that convert will do the necessary validity
3432 Ensure_Valid
(Sub
, Holes_OK
=> True);
3434 -- Move to next subscript
3438 end Apply_Subscript_Validity_Checks
;
3440 ----------------------------------
3441 -- Apply_Type_Conversion_Checks --
3442 ----------------------------------
3444 procedure Apply_Type_Conversion_Checks
(N
: Node_Id
) is
3445 Target_Type
: constant Entity_Id
:= Etype
(N
);
3446 Target_Base
: constant Entity_Id
:= Base_Type
(Target_Type
);
3447 Expr
: constant Node_Id
:= Expression
(N
);
3449 Expr_Type
: constant Entity_Id
:= Underlying_Type
(Etype
(Expr
));
3450 -- Note: if Etype (Expr) is a private type without discriminants, its
3451 -- full view might have discriminants with defaults, so we need the
3452 -- full view here to retrieve the constraints.
3455 if Inside_A_Generic
then
3458 -- Skip these checks if serious errors detected, there are some nasty
3459 -- situations of incomplete trees that blow things up.
3461 elsif Serious_Errors_Detected
> 0 then
3464 -- Never generate discriminant checks for Unchecked_Union types
3466 elsif Present
(Expr_Type
)
3467 and then Is_Unchecked_Union
(Expr_Type
)
3471 -- Scalar type conversions of the form Target_Type (Expr) require a
3472 -- range check if we cannot be sure that Expr is in the base type of
3473 -- Target_Typ and also that Expr is in the range of Target_Typ. These
3474 -- are not quite the same condition from an implementation point of
3475 -- view, but clearly the second includes the first.
3477 elsif Is_Scalar_Type
(Target_Type
) then
3479 Conv_OK
: constant Boolean := Conversion_OK
(N
);
3480 -- If the Conversion_OK flag on the type conversion is set and no
3481 -- floating-point type is involved in the type conversion then
3482 -- fixed-point values must be read as integral values.
3484 Float_To_Int
: constant Boolean :=
3485 Is_Floating_Point_Type
(Expr_Type
)
3486 and then Is_Integer_Type
(Target_Type
);
3489 if not Overflow_Checks_Suppressed
(Target_Base
)
3490 and then not Overflow_Checks_Suppressed
(Target_Type
)
3492 In_Subrange_Of
(Expr_Type
, Target_Base
, Fixed_Int
=> Conv_OK
)
3493 and then not Float_To_Int
3495 -- A small optimization: the attribute 'Pos applied to an
3496 -- enumeration type has a known range, even though its type is
3497 -- Universal_Integer. So in numeric conversions it is usually
3498 -- within range of the target integer type. Use the static
3499 -- bounds of the base types to check. Disable this optimization
3500 -- in case of a generic formal discrete type, because we don't
3501 -- necessarily know the upper bound yet.
3503 if Nkind
(Expr
) = N_Attribute_Reference
3504 and then Attribute_Name
(Expr
) = Name_Pos
3505 and then Is_Enumeration_Type
(Etype
(Prefix
(Expr
)))
3506 and then not Is_Generic_Type
(Etype
(Prefix
(Expr
)))
3507 and then Is_Integer_Type
(Target_Type
)
3510 Enum_T
: constant Entity_Id
:=
3511 Root_Type
(Etype
(Prefix
(Expr
)));
3512 Int_T
: constant Entity_Id
:= Base_Type
(Target_Type
);
3513 Last_I
: constant Uint
:=
3514 Intval
(High_Bound
(Scalar_Range
(Int_T
)));
3518 -- Character types have no explicit literals, so we use
3519 -- the known number of characters in the type.
3521 if Root_Type
(Enum_T
) = Standard_Character
then
3522 Last_E
:= UI_From_Int
(255);
3524 elsif Enum_T
= Standard_Wide_Character
3525 or else Enum_T
= Standard_Wide_Wide_Character
3527 Last_E
:= UI_From_Int
(65535);
3532 (Entity
(High_Bound
(Scalar_Range
(Enum_T
))));
3535 if Last_E
<= Last_I
then
3539 Activate_Overflow_Check
(N
);
3544 Activate_Overflow_Check
(N
);
3548 if not Range_Checks_Suppressed
(Target_Type
)
3549 and then not Range_Checks_Suppressed
(Expr_Type
)
3552 and then not GNATprove_Mode
3554 Apply_Float_Conversion_Check
(Expr
, Target_Type
);
3556 Apply_Scalar_Range_Check
3557 (Expr
, Target_Type
, Fixed_Int
=> Conv_OK
);
3559 -- If the target type has predicates, we need to indicate
3560 -- the need for a check, even if Determine_Range finds that
3561 -- the value is within bounds. This may be the case e.g for
3562 -- a division with a constant denominator.
3564 if Has_Predicates
(Target_Type
) then
3565 Enable_Range_Check
(Expr
);
3571 elsif Comes_From_Source
(N
)
3572 and then not Discriminant_Checks_Suppressed
(Target_Type
)
3573 and then Is_Record_Type
(Target_Type
)
3574 and then Is_Derived_Type
(Target_Type
)
3575 and then not Is_Tagged_Type
(Target_Type
)
3576 and then not Is_Constrained
(Target_Type
)
3577 and then Present
(Stored_Constraint
(Target_Type
))
3579 -- An unconstrained derived type may have inherited discriminant.
3580 -- Build an actual discriminant constraint list using the stored
3581 -- constraint, to verify that the expression of the parent type
3582 -- satisfies the constraints imposed by the (unconstrained) derived
3583 -- type. This applies to value conversions, not to view conversions
3587 Loc
: constant Source_Ptr
:= Sloc
(N
);
3589 Constraint
: Elmt_Id
;
3590 Discr_Value
: Node_Id
;
3593 New_Constraints
: constant Elist_Id
:= New_Elmt_List
;
3594 Old_Constraints
: constant Elist_Id
:=
3595 Discriminant_Constraint
(Expr_Type
);
3598 Constraint
:= First_Elmt
(Stored_Constraint
(Target_Type
));
3599 while Present
(Constraint
) loop
3600 Discr_Value
:= Node
(Constraint
);
3602 if Is_Entity_Name
(Discr_Value
)
3603 and then Ekind
(Entity
(Discr_Value
)) = E_Discriminant
3605 Discr
:= Corresponding_Discriminant
(Entity
(Discr_Value
));
3608 and then Scope
(Discr
) = Base_Type
(Expr_Type
)
3610 -- Parent is constrained by new discriminant. Obtain
3611 -- Value of original discriminant in expression. If the
3612 -- new discriminant has been used to constrain more than
3613 -- one of the stored discriminants, this will provide the
3614 -- required consistency check.
3617 (Make_Selected_Component
(Loc
,
3619 Duplicate_Subexpr_No_Checks
3620 (Expr
, Name_Req
=> True),
3622 Make_Identifier
(Loc
, Chars
(Discr
))),
3626 -- Discriminant of more remote ancestor ???
3631 -- Derived type definition has an explicit value for this
3632 -- stored discriminant.
3636 (Duplicate_Subexpr_No_Checks
(Discr_Value
),
3640 Next_Elmt
(Constraint
);
3643 -- Use the unconstrained expression type to retrieve the
3644 -- discriminants of the parent, and apply momentarily the
3645 -- discriminant constraint synthesized above.
3647 Set_Discriminant_Constraint
(Expr_Type
, New_Constraints
);
3648 Cond
:= Build_Discriminant_Checks
(Expr
, Expr_Type
);
3649 Set_Discriminant_Constraint
(Expr_Type
, Old_Constraints
);
3652 Make_Raise_Constraint_Error
(Loc
,
3654 Reason
=> CE_Discriminant_Check_Failed
));
3657 -- For arrays, checks are set now, but conversions are applied during
3658 -- expansion, to take into accounts changes of representation. The
3659 -- checks become range checks on the base type or length checks on the
3660 -- subtype, depending on whether the target type is unconstrained or
3661 -- constrained. Note that the range check is put on the expression of a
3662 -- type conversion, while the length check is put on the type conversion
3665 elsif Is_Array_Type
(Target_Type
) then
3666 if Is_Constrained
(Target_Type
) then
3667 Set_Do_Length_Check
(N
);
3669 Set_Do_Range_Check
(Expr
);
3672 end Apply_Type_Conversion_Checks
;
3674 ----------------------------------------------
3675 -- Apply_Universal_Integer_Attribute_Checks --
3676 ----------------------------------------------
3678 procedure Apply_Universal_Integer_Attribute_Checks
(N
: Node_Id
) is
3679 Loc
: constant Source_Ptr
:= Sloc
(N
);
3680 Typ
: constant Entity_Id
:= Etype
(N
);
3683 if Inside_A_Generic
then
3686 -- Nothing to do if checks are suppressed
3688 elsif Range_Checks_Suppressed
(Typ
)
3689 and then Overflow_Checks_Suppressed
(Typ
)
3693 -- Nothing to do if the attribute does not come from source. The
3694 -- internal attributes we generate of this type do not need checks,
3695 -- and furthermore the attempt to check them causes some circular
3696 -- elaboration orders when dealing with packed types.
3698 elsif not Comes_From_Source
(N
) then
3701 -- If the prefix is a selected component that depends on a discriminant
3702 -- the check may improperly expose a discriminant instead of using
3703 -- the bounds of the object itself. Set the type of the attribute to
3704 -- the base type of the context, so that a check will be imposed when
3705 -- needed (e.g. if the node appears as an index).
3707 elsif Nkind
(Prefix
(N
)) = N_Selected_Component
3708 and then Ekind
(Typ
) = E_Signed_Integer_Subtype
3709 and then Depends_On_Discriminant
(Scalar_Range
(Typ
))
3711 Set_Etype
(N
, Base_Type
(Typ
));
3713 -- Otherwise, replace the attribute node with a type conversion node
3714 -- whose expression is the attribute, retyped to universal integer, and
3715 -- whose subtype mark is the target type. The call to analyze this
3716 -- conversion will set range and overflow checks as required for proper
3717 -- detection of an out of range value.
3720 Set_Etype
(N
, Universal_Integer
);
3721 Set_Analyzed
(N
, True);
3724 Make_Type_Conversion
(Loc
,
3725 Subtype_Mark
=> New_Occurrence_Of
(Typ
, Loc
),
3726 Expression
=> Relocate_Node
(N
)));
3728 Analyze_And_Resolve
(N
, Typ
);
3731 end Apply_Universal_Integer_Attribute_Checks
;
3733 -------------------------------------
3734 -- Atomic_Synchronization_Disabled --
3735 -------------------------------------
3737 -- Note: internally Disable/Enable_Atomic_Synchronization is implemented
3738 -- using a bogus check called Atomic_Synchronization. This is to make it
3739 -- more convenient to get exactly the same semantics as [Un]Suppress.
3741 function Atomic_Synchronization_Disabled
(E
: Entity_Id
) return Boolean is
3743 -- If debug flag d.e is set, always return False, i.e. all atomic sync
3744 -- looks enabled, since it is never disabled.
3746 if Debug_Flag_Dot_E
then
3749 -- If debug flag d.d is set then always return True, i.e. all atomic
3750 -- sync looks disabled, since it always tests True.
3752 elsif Debug_Flag_Dot_D
then
3755 -- If entity present, then check result for that entity
3757 elsif Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
3758 return Is_Check_Suppressed
(E
, Atomic_Synchronization
);
3760 -- Otherwise result depends on current scope setting
3763 return Scope_Suppress
.Suppress
(Atomic_Synchronization
);
3765 end Atomic_Synchronization_Disabled
;
3767 -------------------------------
3768 -- Build_Discriminant_Checks --
3769 -------------------------------
3771 function Build_Discriminant_Checks
3773 T_Typ
: Entity_Id
) return Node_Id
3775 Loc
: constant Source_Ptr
:= Sloc
(N
);
3778 Disc_Ent
: Entity_Id
;
3782 function Aggregate_Discriminant_Val
(Disc
: Entity_Id
) return Node_Id
;
3784 --------------------------------
3785 -- Aggregate_Discriminant_Val --
3786 --------------------------------
3788 function Aggregate_Discriminant_Val
(Disc
: Entity_Id
) return Node_Id
is
3792 -- The aggregate has been normalized with named associations. We use
3793 -- the Chars field to locate the discriminant to take into account
3794 -- discriminants in derived types, which carry the same name as those
3797 Assoc
:= First
(Component_Associations
(N
));
3798 while Present
(Assoc
) loop
3799 if Chars
(First
(Choices
(Assoc
))) = Chars
(Disc
) then
3800 return Expression
(Assoc
);
3806 -- Discriminant must have been found in the loop above
3808 raise Program_Error
;
3809 end Aggregate_Discriminant_Val
;
3811 -- Start of processing for Build_Discriminant_Checks
3814 -- Loop through discriminants evolving the condition
3817 Disc
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
3819 -- For a fully private type, use the discriminants of the parent type
3821 if Is_Private_Type
(T_Typ
)
3822 and then No
(Full_View
(T_Typ
))
3824 Disc_Ent
:= First_Discriminant
(Etype
(Base_Type
(T_Typ
)));
3826 Disc_Ent
:= First_Discriminant
(T_Typ
);
3829 while Present
(Disc
) loop
3830 Dval
:= Node
(Disc
);
3832 if Nkind
(Dval
) = N_Identifier
3833 and then Ekind
(Entity
(Dval
)) = E_Discriminant
3835 Dval
:= New_Occurrence_Of
(Discriminal
(Entity
(Dval
)), Loc
);
3837 Dval
:= Duplicate_Subexpr_No_Checks
(Dval
);
3840 -- If we have an Unchecked_Union node, we can infer the discriminants
3843 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
3845 Get_Discriminant_Value
(
3846 First_Discriminant
(T_Typ
),
3848 Stored_Constraint
(T_Typ
)));
3850 elsif Nkind
(N
) = N_Aggregate
then
3852 Duplicate_Subexpr_No_Checks
3853 (Aggregate_Discriminant_Val
(Disc_Ent
));
3857 Make_Selected_Component
(Loc
,
3859 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
3860 Selector_Name
=> Make_Identifier
(Loc
, Chars
(Disc_Ent
)));
3862 Set_Is_In_Discriminant_Check
(Dref
);
3865 Evolve_Or_Else
(Cond
,
3868 Right_Opnd
=> Dval
));
3871 Next_Discriminant
(Disc_Ent
);
3875 end Build_Discriminant_Checks
;
3881 function Check_Needed
(Nod
: Node_Id
; Check
: Check_Type
) return Boolean is
3888 function Left_Expression
(Op
: Node_Id
) return Node_Id
;
3889 -- Return the relevant expression from the left operand of the given
3890 -- short circuit form: this is LO itself, except if LO is a qualified
3891 -- expression, a type conversion, or an expression with actions, in
3892 -- which case this is Left_Expression (Expression (LO)).
3894 ---------------------
3895 -- Left_Expression --
3896 ---------------------
3898 function Left_Expression
(Op
: Node_Id
) return Node_Id
is
3899 LE
: Node_Id
:= Left_Opnd
(Op
);
3901 while Nkind_In
(LE
, N_Qualified_Expression
,
3903 N_Expression_With_Actions
)
3905 LE
:= Expression
(LE
);
3909 end Left_Expression
;
3911 -- Start of processing for Check_Needed
3914 -- Always check if not simple entity
3916 if Nkind
(Nod
) not in N_Has_Entity
3917 or else not Comes_From_Source
(Nod
)
3922 -- Look up tree for short circuit
3929 -- Done if out of subexpression (note that we allow generated stuff
3930 -- such as itype declarations in this context, to keep the loop going
3931 -- since we may well have generated such stuff in complex situations.
3932 -- Also done if no parent (probably an error condition, but no point
3933 -- in behaving nasty if we find it).
3936 or else (K
not in N_Subexpr
and then Comes_From_Source
(P
))
3940 -- Or/Or Else case, where test is part of the right operand, or is
3941 -- part of one of the actions associated with the right operand, and
3942 -- the left operand is an equality test.
3944 elsif K
= N_Op_Or
then
3945 exit when N
= Right_Opnd
(P
)
3946 and then Nkind
(Left_Expression
(P
)) = N_Op_Eq
;
3948 elsif K
= N_Or_Else
then
3949 exit when (N
= Right_Opnd
(P
)
3952 and then List_Containing
(N
) = Actions
(P
)))
3953 and then Nkind
(Left_Expression
(P
)) = N_Op_Eq
;
3955 -- Similar test for the And/And then case, where the left operand
3956 -- is an inequality test.
3958 elsif K
= N_Op_And
then
3959 exit when N
= Right_Opnd
(P
)
3960 and then Nkind
(Left_Expression
(P
)) = N_Op_Ne
;
3962 elsif K
= N_And_Then
then
3963 exit when (N
= Right_Opnd
(P
)
3966 and then List_Containing
(N
) = Actions
(P
)))
3967 and then Nkind
(Left_Expression
(P
)) = N_Op_Ne
;
3973 -- If we fall through the loop, then we have a conditional with an
3974 -- appropriate test as its left operand, so look further.
3976 L
:= Left_Expression
(P
);
3978 -- L is an "=" or "/=" operator: extract its operands
3980 R
:= Right_Opnd
(L
);
3983 -- Left operand of test must match original variable
3985 if Nkind
(L
) not in N_Has_Entity
or else Entity
(L
) /= Entity
(Nod
) then
3989 -- Right operand of test must be key value (zero or null)
3992 when Access_Check
=>
3993 if not Known_Null
(R
) then
3997 when Division_Check
=>
3998 if not Compile_Time_Known_Value
(R
)
3999 or else Expr_Value
(R
) /= Uint_0
4005 raise Program_Error
;
4008 -- Here we have the optimizable case, warn if not short-circuited
4010 if K
= N_Op_And
or else K
= N_Op_Or
then
4011 Error_Msg_Warn
:= SPARK_Mode
/= On
;
4014 when Access_Check
=>
4015 if GNATprove_Mode
then
4017 ("Constraint_Error might have been raised (access check)",
4021 ("Constraint_Error may be raised (access check)??",
4025 when Division_Check
=>
4026 if GNATprove_Mode
then
4028 ("Constraint_Error might have been raised (zero divide)",
4032 ("Constraint_Error may be raised (zero divide)??",
4037 raise Program_Error
;
4040 if K
= N_Op_And
then
4041 Error_Msg_N
-- CODEFIX
4042 ("use `AND THEN` instead of AND??", P
);
4044 Error_Msg_N
-- CODEFIX
4045 ("use `OR ELSE` instead of OR??", P
);
4048 -- If not short-circuited, we need the check
4052 -- If short-circuited, we can omit the check
4059 -----------------------------------
4060 -- Check_Valid_Lvalue_Subscripts --
4061 -----------------------------------
4063 procedure Check_Valid_Lvalue_Subscripts
(Expr
: Node_Id
) is
4065 -- Skip this if range checks are suppressed
4067 if Range_Checks_Suppressed
(Etype
(Expr
)) then
4070 -- Only do this check for expressions that come from source. We assume
4071 -- that expander generated assignments explicitly include any necessary
4072 -- checks. Note that this is not just an optimization, it avoids
4073 -- infinite recursions.
4075 elsif not Comes_From_Source
(Expr
) then
4078 -- For a selected component, check the prefix
4080 elsif Nkind
(Expr
) = N_Selected_Component
then
4081 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
4084 -- Case of indexed component
4086 elsif Nkind
(Expr
) = N_Indexed_Component
then
4087 Apply_Subscript_Validity_Checks
(Expr
);
4089 -- Prefix may itself be or contain an indexed component, and these
4090 -- subscripts need checking as well.
4092 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
4094 end Check_Valid_Lvalue_Subscripts
;
4096 ----------------------------------
4097 -- Null_Exclusion_Static_Checks --
4098 ----------------------------------
4100 procedure Null_Exclusion_Static_Checks
4102 Comp
: Node_Id
:= Empty
;
4103 Array_Comp
: Boolean := False)
4105 Has_Null
: constant Boolean := Has_Null_Exclusion
(N
);
4106 Kind
: constant Node_Kind
:= Nkind
(N
);
4107 Error_Nod
: Node_Id
;
4113 (Nkind_In
(Kind
, N_Component_Declaration
,
4114 N_Discriminant_Specification
,
4115 N_Function_Specification
,
4116 N_Object_Declaration
,
4117 N_Parameter_Specification
));
4119 if Kind
= N_Function_Specification
then
4120 Typ
:= Etype
(Defining_Entity
(N
));
4122 Typ
:= Etype
(Defining_Identifier
(N
));
4126 when N_Component_Declaration
=>
4127 if Present
(Access_Definition
(Component_Definition
(N
))) then
4128 Error_Nod
:= Component_Definition
(N
);
4130 Error_Nod
:= Subtype_Indication
(Component_Definition
(N
));
4133 when N_Discriminant_Specification
=>
4134 Error_Nod
:= Discriminant_Type
(N
);
4136 when N_Function_Specification
=>
4137 Error_Nod
:= Result_Definition
(N
);
4139 when N_Object_Declaration
=>
4140 Error_Nod
:= Object_Definition
(N
);
4142 when N_Parameter_Specification
=>
4143 Error_Nod
:= Parameter_Type
(N
);
4146 raise Program_Error
;
4151 -- Enforce legality rule 3.10 (13): A null exclusion can only be
4152 -- applied to an access [sub]type.
4154 if not Is_Access_Type
(Typ
) then
4156 ("`NOT NULL` allowed only for an access type", Error_Nod
);
4158 -- Enforce legality rule RM 3.10(14/1): A null exclusion can only
4159 -- be applied to a [sub]type that does not exclude null already.
4161 elsif Can_Never_Be_Null
(Typ
) and then Comes_From_Source
(Typ
) then
4163 ("`NOT NULL` not allowed (& already excludes null)",
4168 -- Check that null-excluding objects are always initialized, except for
4169 -- deferred constants, for which the expression will appear in the full
4172 if Kind
= N_Object_Declaration
4173 and then No
(Expression
(N
))
4174 and then not Constant_Present
(N
)
4175 and then not No_Initialization
(N
)
4177 if Present
(Comp
) then
4179 -- Specialize the warning message to indicate that we are dealing
4180 -- with an uninitialized composite object that has a defaulted
4181 -- null-excluding component.
4183 Error_Msg_Name_1
:= Chars
(Defining_Identifier
(Comp
));
4184 Error_Msg_Name_2
:= Chars
(Defining_Identifier
(N
));
4187 (Compile_Time_Constraint_Error
4190 "(Ada 2005) null-excluding component % of object % must "
4191 & "be initialized??",
4192 Ent
=> Defining_Identifier
(Comp
)));
4194 -- This is a case of an array with null-excluding components, so
4195 -- indicate that in the warning.
4197 elsif Array_Comp
then
4199 (Compile_Time_Constraint_Error
4202 "(Ada 2005) null-excluding array components must "
4203 & "be initialized??",
4204 Ent
=> Defining_Identifier
(N
)));
4206 -- Normal case of object of a null-excluding access type
4209 -- Add an expression that assigns null. This node is needed by
4210 -- Apply_Compile_Time_Constraint_Error, which will replace this
4211 -- with a Constraint_Error node.
4213 Set_Expression
(N
, Make_Null
(Sloc
(N
)));
4214 Set_Etype
(Expression
(N
), Etype
(Defining_Identifier
(N
)));
4216 Apply_Compile_Time_Constraint_Error
4217 (N
=> Expression
(N
),
4219 "(Ada 2005) null-excluding objects must be initialized??",
4220 Reason
=> CE_Null_Not_Allowed
);
4224 -- Check that a null-excluding component, formal or object is not being
4225 -- assigned a null value. Otherwise generate a warning message and
4226 -- replace Expression (N) by an N_Constraint_Error node.
4228 if Kind
/= N_Function_Specification
then
4229 Expr
:= Expression
(N
);
4231 if Present
(Expr
) and then Known_Null
(Expr
) then
4233 when N_Component_Declaration
4234 | N_Discriminant_Specification
4236 Apply_Compile_Time_Constraint_Error
4239 "(Ada 2005) null not allowed in null-excluding "
4241 Reason
=> CE_Null_Not_Allowed
);
4243 when N_Object_Declaration
=>
4244 Apply_Compile_Time_Constraint_Error
4247 "(Ada 2005) null not allowed in null-excluding "
4249 Reason
=> CE_Null_Not_Allowed
);
4251 when N_Parameter_Specification
=>
4252 Apply_Compile_Time_Constraint_Error
4255 "(Ada 2005) null not allowed in null-excluding "
4257 Reason
=> CE_Null_Not_Allowed
);
4264 end Null_Exclusion_Static_Checks
;
4266 ----------------------------------
4267 -- Conditional_Statements_Begin --
4268 ----------------------------------
4270 procedure Conditional_Statements_Begin
is
4272 Saved_Checks_TOS
:= Saved_Checks_TOS
+ 1;
4274 -- If stack overflows, kill all checks, that way we know to simply reset
4275 -- the number of saved checks to zero on return. This should never occur
4278 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
4281 -- In the normal case, we just make a new stack entry saving the current
4282 -- number of saved checks for a later restore.
4285 Saved_Checks_Stack
(Saved_Checks_TOS
) := Num_Saved_Checks
;
4287 if Debug_Flag_CC
then
4288 w
("Conditional_Statements_Begin: Num_Saved_Checks = ",
4292 end Conditional_Statements_Begin
;
4294 --------------------------------
4295 -- Conditional_Statements_End --
4296 --------------------------------
4298 procedure Conditional_Statements_End
is
4300 pragma Assert
(Saved_Checks_TOS
> 0);
4302 -- If the saved checks stack overflowed, then we killed all checks, so
4303 -- setting the number of saved checks back to zero is correct. This
4304 -- should never occur in practice.
4306 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
4307 Num_Saved_Checks
:= 0;
4309 -- In the normal case, restore the number of saved checks from the top
4313 Num_Saved_Checks
:= Saved_Checks_Stack
(Saved_Checks_TOS
);
4315 if Debug_Flag_CC
then
4316 w
("Conditional_Statements_End: Num_Saved_Checks = ",
4321 Saved_Checks_TOS
:= Saved_Checks_TOS
- 1;
4322 end Conditional_Statements_End
;
4324 -------------------------
4325 -- Convert_From_Bignum --
4326 -------------------------
4328 function Convert_From_Bignum
(N
: Node_Id
) return Node_Id
is
4329 Loc
: constant Source_Ptr
:= Sloc
(N
);
4332 pragma Assert
(Is_RTE
(Etype
(N
), RE_Bignum
));
4334 -- Construct call From Bignum
4337 Make_Function_Call
(Loc
,
4339 New_Occurrence_Of
(RTE
(RE_From_Bignum
), Loc
),
4340 Parameter_Associations
=> New_List
(Relocate_Node
(N
)));
4341 end Convert_From_Bignum
;
4343 -----------------------
4344 -- Convert_To_Bignum --
4345 -----------------------
4347 function Convert_To_Bignum
(N
: Node_Id
) return Node_Id
is
4348 Loc
: constant Source_Ptr
:= Sloc
(N
);
4351 -- Nothing to do if Bignum already except call Relocate_Node
4353 if Is_RTE
(Etype
(N
), RE_Bignum
) then
4354 return Relocate_Node
(N
);
4356 -- Otherwise construct call to To_Bignum, converting the operand to the
4357 -- required Long_Long_Integer form.
4360 pragma Assert
(Is_Signed_Integer_Type
(Etype
(N
)));
4362 Make_Function_Call
(Loc
,
4364 New_Occurrence_Of
(RTE
(RE_To_Bignum
), Loc
),
4365 Parameter_Associations
=> New_List
(
4366 Convert_To
(Standard_Long_Long_Integer
, Relocate_Node
(N
))));
4368 end Convert_To_Bignum
;
4370 ---------------------
4371 -- Determine_Range --
4372 ---------------------
4374 Cache_Size
: constant := 2 ** 10;
4375 type Cache_Index
is range 0 .. Cache_Size
- 1;
4376 -- Determine size of below cache (power of 2 is more efficient)
4378 Determine_Range_Cache_N
: array (Cache_Index
) of Node_Id
;
4379 Determine_Range_Cache_V
: array (Cache_Index
) of Boolean;
4380 Determine_Range_Cache_Lo
: array (Cache_Index
) of Uint
;
4381 Determine_Range_Cache_Hi
: array (Cache_Index
) of Uint
;
4382 Determine_Range_Cache_Lo_R
: array (Cache_Index
) of Ureal
;
4383 Determine_Range_Cache_Hi_R
: array (Cache_Index
) of Ureal
;
4384 -- The above arrays are used to implement a small direct cache for
4385 -- Determine_Range and Determine_Range_R calls. Because of the way these
4386 -- subprograms recursively traces subexpressions, and because overflow
4387 -- checking calls the routine on the way up the tree, a quadratic behavior
4388 -- can otherwise be encountered in large expressions. The cache entry for
4389 -- node N is stored in the (N mod Cache_Size) entry, and can be validated
4390 -- by checking the actual node value stored there. The Range_Cache_V array
4391 -- records the setting of Assume_Valid for the cache entry.
4393 procedure Determine_Range
4398 Assume_Valid
: Boolean := False)
4400 Typ
: Entity_Id
:= Etype
(N
);
4401 -- Type to use, may get reset to base type for possibly invalid entity
4405 -- Lo and Hi bounds of left operand
4407 Lo_Right
: Uint
:= No_Uint
;
4408 Hi_Right
: Uint
:= No_Uint
;
4409 -- Lo and Hi bounds of right (or only) operand
4412 -- Temp variable used to hold a bound node
4415 -- High bound of base type of expression
4419 -- Refined values for low and high bounds, after tightening
4422 -- Used in lower level calls to indicate if call succeeded
4424 Cindex
: Cache_Index
;
4425 -- Used to search cache
4430 function OK_Operands
return Boolean;
4431 -- Used for binary operators. Determines the ranges of the left and
4432 -- right operands, and if they are both OK, returns True, and puts
4433 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left.
4439 function OK_Operands
return Boolean is
4442 (Left_Opnd
(N
), OK1
, Lo_Left
, Hi_Left
, Assume_Valid
);
4449 (Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
, Assume_Valid
);
4453 -- Start of processing for Determine_Range
4456 -- Prevent junk warnings by initializing range variables
4463 -- For temporary constants internally generated to remove side effects
4464 -- we must use the corresponding expression to determine the range of
4465 -- the expression. But note that the expander can also generate
4466 -- constants in other cases, including deferred constants.
4468 if Is_Entity_Name
(N
)
4469 and then Nkind
(Parent
(Entity
(N
))) = N_Object_Declaration
4470 and then Ekind
(Entity
(N
)) = E_Constant
4471 and then Is_Internal_Name
(Chars
(Entity
(N
)))
4473 if Present
(Expression
(Parent
(Entity
(N
)))) then
4475 (Expression
(Parent
(Entity
(N
))), OK
, Lo
, Hi
, Assume_Valid
);
4477 elsif Present
(Full_View
(Entity
(N
))) then
4479 (Expression
(Parent
(Full_View
(Entity
(N
)))),
4480 OK
, Lo
, Hi
, Assume_Valid
);
4488 -- If type is not defined, we can't determine its range
4492 -- We don't deal with anything except discrete types
4494 or else not Is_Discrete_Type
(Typ
)
4496 -- Ignore type for which an error has been posted, since range in
4497 -- this case may well be a bogosity deriving from the error. Also
4498 -- ignore if error posted on the reference node.
4500 or else Error_Posted
(N
) or else Error_Posted
(Typ
)
4506 -- For all other cases, we can determine the range
4510 -- If value is compile time known, then the possible range is the one
4511 -- value that we know this expression definitely has.
4513 if Compile_Time_Known_Value
(N
) then
4514 Lo
:= Expr_Value
(N
);
4519 -- Return if already in the cache
4521 Cindex
:= Cache_Index
(N
mod Cache_Size
);
4523 if Determine_Range_Cache_N
(Cindex
) = N
4525 Determine_Range_Cache_V
(Cindex
) = Assume_Valid
4527 Lo
:= Determine_Range_Cache_Lo
(Cindex
);
4528 Hi
:= Determine_Range_Cache_Hi
(Cindex
);
4532 -- Otherwise, start by finding the bounds of the type of the expression,
4533 -- the value cannot be outside this range (if it is, then we have an
4534 -- overflow situation, which is a separate check, we are talking here
4535 -- only about the expression value).
4537 -- First a check, never try to find the bounds of a generic type, since
4538 -- these bounds are always junk values, and it is only valid to look at
4539 -- the bounds in an instance.
4541 if Is_Generic_Type
(Typ
) then
4546 -- First step, change to use base type unless we know the value is valid
4548 if (Is_Entity_Name
(N
) and then Is_Known_Valid
(Entity
(N
)))
4549 or else Assume_No_Invalid_Values
4550 or else Assume_Valid
4554 Typ
:= Underlying_Type
(Base_Type
(Typ
));
4557 -- Retrieve the base type. Handle the case where the base type is a
4558 -- private enumeration type.
4560 Btyp
:= Base_Type
(Typ
);
4562 if Is_Private_Type
(Btyp
) and then Present
(Full_View
(Btyp
)) then
4563 Btyp
:= Full_View
(Btyp
);
4566 -- We use the actual bound unless it is dynamic, in which case use the
4567 -- corresponding base type bound if possible. If we can't get a bound
4568 -- then we figure we can't determine the range (a peculiar case, that
4569 -- perhaps cannot happen, but there is no point in bombing in this
4570 -- optimization circuit.
4572 -- First the low bound
4574 Bound
:= Type_Low_Bound
(Typ
);
4576 if Compile_Time_Known_Value
(Bound
) then
4577 Lo
:= Expr_Value
(Bound
);
4579 elsif Compile_Time_Known_Value
(Type_Low_Bound
(Btyp
)) then
4580 Lo
:= Expr_Value
(Type_Low_Bound
(Btyp
));
4587 -- Now the high bound
4589 Bound
:= Type_High_Bound
(Typ
);
4591 -- We need the high bound of the base type later on, and this should
4592 -- always be compile time known. Again, it is not clear that this
4593 -- can ever be false, but no point in bombing.
4595 if Compile_Time_Known_Value
(Type_High_Bound
(Btyp
)) then
4596 Hbound
:= Expr_Value
(Type_High_Bound
(Btyp
));
4604 -- If we have a static subtype, then that may have a tighter bound so
4605 -- use the upper bound of the subtype instead in this case.
4607 if Compile_Time_Known_Value
(Bound
) then
4608 Hi
:= Expr_Value
(Bound
);
4611 -- We may be able to refine this value in certain situations. If any
4612 -- refinement is possible, then Lor and Hir are set to possibly tighter
4613 -- bounds, and OK1 is set to True.
4617 -- For unary plus, result is limited by range of operand
4621 (Right_Opnd
(N
), OK1
, Lor
, Hir
, Assume_Valid
);
4623 -- For unary minus, determine range of operand, and negate it
4627 (Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
, Assume_Valid
);
4634 -- For binary addition, get range of each operand and do the
4635 -- addition to get the result range.
4639 Lor
:= Lo_Left
+ Lo_Right
;
4640 Hir
:= Hi_Left
+ Hi_Right
;
4643 -- Division is tricky. The only case we consider is where the right
4644 -- operand is a positive constant, and in this case we simply divide
4645 -- the bounds of the left operand
4649 if Lo_Right
= Hi_Right
4650 and then Lo_Right
> 0
4652 Lor
:= Lo_Left
/ Lo_Right
;
4653 Hir
:= Hi_Left
/ Lo_Right
;
4659 -- For binary subtraction, get range of each operand and do the worst
4660 -- case subtraction to get the result range.
4662 when N_Op_Subtract
=>
4664 Lor
:= Lo_Left
- Hi_Right
;
4665 Hir
:= Hi_Left
- Lo_Right
;
4668 -- For MOD, if right operand is a positive constant, then result must
4669 -- be in the allowable range of mod results.
4673 if Lo_Right
= Hi_Right
4674 and then Lo_Right
/= 0
4676 if Lo_Right
> 0 then
4678 Hir
:= Lo_Right
- 1;
4680 else -- Lo_Right < 0
4681 Lor
:= Lo_Right
+ 1;
4690 -- For REM, if right operand is a positive constant, then result must
4691 -- be in the allowable range of mod results.
4695 if Lo_Right
= Hi_Right
and then Lo_Right
/= 0 then
4697 Dval
: constant Uint
:= (abs Lo_Right
) - 1;
4700 -- The sign of the result depends on the sign of the
4701 -- dividend (but not on the sign of the divisor, hence
4702 -- the abs operation above).
4722 -- Attribute reference cases
4724 when N_Attribute_Reference
=>
4725 case Attribute_Name
(N
) is
4727 -- For Pos/Val attributes, we can refine the range using the
4728 -- possible range of values of the attribute expression.
4734 (First
(Expressions
(N
)), OK1
, Lor
, Hir
, Assume_Valid
);
4736 -- For Length attribute, use the bounds of the corresponding
4737 -- index type to refine the range.
4741 Atyp
: Entity_Id
:= Etype
(Prefix
(N
));
4749 if Is_Access_Type
(Atyp
) then
4750 Atyp
:= Designated_Type
(Atyp
);
4753 -- For string literal, we know exact value
4755 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
4757 Lo
:= String_Literal_Length
(Atyp
);
4758 Hi
:= String_Literal_Length
(Atyp
);
4762 -- Otherwise check for expression given
4764 if No
(Expressions
(N
)) then
4768 UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
4771 Indx
:= First_Index
(Atyp
);
4772 for J
in 2 .. Inum
loop
4773 Indx
:= Next_Index
(Indx
);
4776 -- If the index type is a formal type or derived from
4777 -- one, the bounds are not static.
4779 if Is_Generic_Type
(Root_Type
(Etype
(Indx
))) then
4785 (Type_Low_Bound
(Etype
(Indx
)), OK1
, LL
, LU
,
4790 (Type_High_Bound
(Etype
(Indx
)), OK1
, UL
, UU
,
4795 -- The maximum value for Length is the biggest
4796 -- possible gap between the values of the bounds.
4797 -- But of course, this value cannot be negative.
4799 Hir
:= UI_Max
(Uint_0
, UU
- LL
+ 1);
4801 -- For constrained arrays, the minimum value for
4802 -- Length is taken from the actual value of the
4803 -- bounds, since the index will be exactly of this
4806 if Is_Constrained
(Atyp
) then
4807 Lor
:= UI_Max
(Uint_0
, UL
- LU
+ 1);
4809 -- For an unconstrained array, the minimum value
4810 -- for length is always zero.
4819 -- No special handling for other attributes
4820 -- Probably more opportunities exist here???
4827 when N_Type_Conversion
=>
4829 -- For type conversion from one discrete type to another, we can
4830 -- refine the range using the converted value.
4832 if Is_Discrete_Type
(Etype
(Expression
(N
))) then
4833 Determine_Range
(Expression
(N
), OK1
, Lor
, Hir
, Assume_Valid
);
4835 -- When converting a float to an integer type, determine the range
4836 -- in real first, and then convert the bounds using UR_To_Uint
4837 -- which correctly rounds away from zero when half way between two
4838 -- integers, as required by normal Ada 95 rounding semantics. It
4839 -- is only possible because analysis in GNATprove rules out the
4840 -- possibility of a NaN or infinite value.
4842 elsif GNATprove_Mode
4843 and then Is_Floating_Point_Type
(Etype
(Expression
(N
)))
4846 Lor_Real
, Hir_Real
: Ureal
;
4848 Determine_Range_R
(Expression
(N
), OK1
, Lor_Real
, Hir_Real
,
4852 Lor
:= UR_To_Uint
(Lor_Real
);
4853 Hir
:= UR_To_Uint
(Hir_Real
);
4861 -- Nothing special to do for all other expression kinds
4869 -- At this stage, if OK1 is true, then we know that the actual result of
4870 -- the computed expression is in the range Lor .. Hir. We can use this
4871 -- to restrict the possible range of results.
4875 -- If the refined value of the low bound is greater than the type
4876 -- low bound, then reset it to the more restrictive value. However,
4877 -- we do NOT do this for the case of a modular type where the
4878 -- possible upper bound on the value is above the base type high
4879 -- bound, because that means the result could wrap.
4882 and then not (Is_Modular_Integer_Type
(Typ
) and then Hir
> Hbound
)
4887 -- Similarly, if the refined value of the high bound is less than the
4888 -- value so far, then reset it to the more restrictive value. Again,
4889 -- we do not do this if the refined low bound is negative for a
4890 -- modular type, since this would wrap.
4893 and then not (Is_Modular_Integer_Type
(Typ
) and then Lor
< Uint_0
)
4899 -- Set cache entry for future call and we are all done
4901 Determine_Range_Cache_N
(Cindex
) := N
;
4902 Determine_Range_Cache_V
(Cindex
) := Assume_Valid
;
4903 Determine_Range_Cache_Lo
(Cindex
) := Lo
;
4904 Determine_Range_Cache_Hi
(Cindex
) := Hi
;
4907 -- If any exception occurs, it means that we have some bug in the compiler,
4908 -- possibly triggered by a previous error, or by some unforeseen peculiar
4909 -- occurrence. However, this is only an optimization attempt, so there is
4910 -- really no point in crashing the compiler. Instead we just decide, too
4911 -- bad, we can't figure out a range in this case after all.
4916 -- Debug flag K disables this behavior (useful for debugging)
4918 if Debug_Flag_K
then
4926 end Determine_Range
;
4928 -----------------------
4929 -- Determine_Range_R --
4930 -----------------------
4932 procedure Determine_Range_R
4937 Assume_Valid
: Boolean := False)
4939 Typ
: Entity_Id
:= Etype
(N
);
4940 -- Type to use, may get reset to base type for possibly invalid entity
4944 -- Lo and Hi bounds of left operand
4946 Lo_Right
: Ureal
:= No_Ureal
;
4947 Hi_Right
: Ureal
:= No_Ureal
;
4948 -- Lo and Hi bounds of right (or only) operand
4951 -- Temp variable used to hold a bound node
4954 -- High bound of base type of expression
4958 -- Refined values for low and high bounds, after tightening
4961 -- Used in lower level calls to indicate if call succeeded
4963 Cindex
: Cache_Index
;
4964 -- Used to search cache
4969 function OK_Operands
return Boolean;
4970 -- Used for binary operators. Determines the ranges of the left and
4971 -- right operands, and if they are both OK, returns True, and puts
4972 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left.
4974 function Round_Machine
(B
: Ureal
) return Ureal
;
4975 -- B is a real bound. Round it using mode Round_Even.
4981 function OK_Operands
return Boolean is
4984 (Left_Opnd
(N
), OK1
, Lo_Left
, Hi_Left
, Assume_Valid
);
4991 (Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
, Assume_Valid
);
4999 function Round_Machine
(B
: Ureal
) return Ureal
is
5001 return Machine
(Typ
, B
, Round_Even
, N
);
5004 -- Start of processing for Determine_Range_R
5007 -- Prevent junk warnings by initializing range variables
5014 -- For temporary constants internally generated to remove side effects
5015 -- we must use the corresponding expression to determine the range of
5016 -- the expression. But note that the expander can also generate
5017 -- constants in other cases, including deferred constants.
5019 if Is_Entity_Name
(N
)
5020 and then Nkind
(Parent
(Entity
(N
))) = N_Object_Declaration
5021 and then Ekind
(Entity
(N
)) = E_Constant
5022 and then Is_Internal_Name
(Chars
(Entity
(N
)))
5024 if Present
(Expression
(Parent
(Entity
(N
)))) then
5026 (Expression
(Parent
(Entity
(N
))), OK
, Lo
, Hi
, Assume_Valid
);
5028 elsif Present
(Full_View
(Entity
(N
))) then
5030 (Expression
(Parent
(Full_View
(Entity
(N
)))),
5031 OK
, Lo
, Hi
, Assume_Valid
);
5040 -- If type is not defined, we can't determine its range
5044 -- We don't deal with anything except IEEE floating-point types
5046 or else not Is_Floating_Point_Type
(Typ
)
5047 or else Float_Rep
(Typ
) /= IEEE_Binary
5049 -- Ignore type for which an error has been posted, since range in
5050 -- this case may well be a bogosity deriving from the error. Also
5051 -- ignore if error posted on the reference node.
5053 or else Error_Posted
(N
) or else Error_Posted
(Typ
)
5059 -- For all other cases, we can determine the range
5063 -- If value is compile time known, then the possible range is the one
5064 -- value that we know this expression definitely has.
5066 if Compile_Time_Known_Value
(N
) then
5067 Lo
:= Expr_Value_R
(N
);
5072 -- Return if already in the cache
5074 Cindex
:= Cache_Index
(N
mod Cache_Size
);
5076 if Determine_Range_Cache_N
(Cindex
) = N
5078 Determine_Range_Cache_V
(Cindex
) = Assume_Valid
5080 Lo
:= Determine_Range_Cache_Lo_R
(Cindex
);
5081 Hi
:= Determine_Range_Cache_Hi_R
(Cindex
);
5085 -- Otherwise, start by finding the bounds of the type of the expression,
5086 -- the value cannot be outside this range (if it is, then we have an
5087 -- overflow situation, which is a separate check, we are talking here
5088 -- only about the expression value).
5090 -- First a check, never try to find the bounds of a generic type, since
5091 -- these bounds are always junk values, and it is only valid to look at
5092 -- the bounds in an instance.
5094 if Is_Generic_Type
(Typ
) then
5099 -- First step, change to use base type unless we know the value is valid
5101 if (Is_Entity_Name
(N
) and then Is_Known_Valid
(Entity
(N
)))
5102 or else Assume_No_Invalid_Values
5103 or else Assume_Valid
5107 Typ
:= Underlying_Type
(Base_Type
(Typ
));
5110 -- Retrieve the base type. Handle the case where the base type is a
5113 Btyp
:= Base_Type
(Typ
);
5115 if Is_Private_Type
(Btyp
) and then Present
(Full_View
(Btyp
)) then
5116 Btyp
:= Full_View
(Btyp
);
5119 -- We use the actual bound unless it is dynamic, in which case use the
5120 -- corresponding base type bound if possible. If we can't get a bound
5121 -- then we figure we can't determine the range (a peculiar case, that
5122 -- perhaps cannot happen, but there is no point in bombing in this
5123 -- optimization circuit).
5125 -- First the low bound
5127 Bound
:= Type_Low_Bound
(Typ
);
5129 if Compile_Time_Known_Value
(Bound
) then
5130 Lo
:= Expr_Value_R
(Bound
);
5132 elsif Compile_Time_Known_Value
(Type_Low_Bound
(Btyp
)) then
5133 Lo
:= Expr_Value_R
(Type_Low_Bound
(Btyp
));
5140 -- Now the high bound
5142 Bound
:= Type_High_Bound
(Typ
);
5144 -- We need the high bound of the base type later on, and this should
5145 -- always be compile time known. Again, it is not clear that this
5146 -- can ever be false, but no point in bombing.
5148 if Compile_Time_Known_Value
(Type_High_Bound
(Btyp
)) then
5149 Hbound
:= Expr_Value_R
(Type_High_Bound
(Btyp
));
5157 -- If we have a static subtype, then that may have a tighter bound so
5158 -- use the upper bound of the subtype instead in this case.
5160 if Compile_Time_Known_Value
(Bound
) then
5161 Hi
:= Expr_Value_R
(Bound
);
5164 -- We may be able to refine this value in certain situations. If any
5165 -- refinement is possible, then Lor and Hir are set to possibly tighter
5166 -- bounds, and OK1 is set to True.
5170 -- For unary plus, result is limited by range of operand
5174 (Right_Opnd
(N
), OK1
, Lor
, Hir
, Assume_Valid
);
5176 -- For unary minus, determine range of operand, and negate it
5180 (Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
, Assume_Valid
);
5187 -- For binary addition, get range of each operand and do the
5188 -- addition to get the result range.
5192 Lor
:= Round_Machine
(Lo_Left
+ Lo_Right
);
5193 Hir
:= Round_Machine
(Hi_Left
+ Hi_Right
);
5196 -- For binary subtraction, get range of each operand and do the worst
5197 -- case subtraction to get the result range.
5199 when N_Op_Subtract
=>
5201 Lor
:= Round_Machine
(Lo_Left
- Hi_Right
);
5202 Hir
:= Round_Machine
(Hi_Left
- Lo_Right
);
5205 -- For multiplication, get range of each operand and do the
5206 -- four multiplications to get the result range.
5208 when N_Op_Multiply
=>
5211 M1
: constant Ureal
:= Round_Machine
(Lo_Left
* Lo_Right
);
5212 M2
: constant Ureal
:= Round_Machine
(Lo_Left
* Hi_Right
);
5213 M3
: constant Ureal
:= Round_Machine
(Hi_Left
* Lo_Right
);
5214 M4
: constant Ureal
:= Round_Machine
(Hi_Left
* Hi_Right
);
5217 Lor
:= UR_Min
(UR_Min
(M1
, M2
), UR_Min
(M3
, M4
));
5218 Hir
:= UR_Max
(UR_Max
(M1
, M2
), UR_Max
(M3
, M4
));
5222 -- For division, consider separately the cases where the right
5223 -- operand is positive or negative. Otherwise, the right operand
5224 -- can be arbitrarily close to zero, so the result is likely to
5225 -- be unbounded in one direction, do not attempt to compute it.
5230 -- Right operand is positive
5232 if Lo_Right
> Ureal_0
then
5234 -- If the low bound of the left operand is negative, obtain
5235 -- the overall low bound by dividing it by the smallest
5236 -- value of the right operand, and otherwise by the largest
5237 -- value of the right operand.
5239 if Lo_Left
< Ureal_0
then
5240 Lor
:= Round_Machine
(Lo_Left
/ Lo_Right
);
5242 Lor
:= Round_Machine
(Lo_Left
/ Hi_Right
);
5245 -- If the high bound of the left operand is negative, obtain
5246 -- the overall high bound by dividing it by the largest
5247 -- value of the right operand, and otherwise by the
5248 -- smallest value of the right operand.
5250 if Hi_Left
< Ureal_0
then
5251 Hir
:= Round_Machine
(Hi_Left
/ Hi_Right
);
5253 Hir
:= Round_Machine
(Hi_Left
/ Lo_Right
);
5256 -- Right operand is negative
5258 elsif Hi_Right
< Ureal_0
then
5260 -- If the low bound of the left operand is negative, obtain
5261 -- the overall low bound by dividing it by the largest
5262 -- value of the right operand, and otherwise by the smallest
5263 -- value of the right operand.
5265 if Lo_Left
< Ureal_0
then
5266 Lor
:= Round_Machine
(Lo_Left
/ Hi_Right
);
5268 Lor
:= Round_Machine
(Lo_Left
/ Lo_Right
);
5271 -- If the high bound of the left operand is negative, obtain
5272 -- the overall high bound by dividing it by the smallest
5273 -- value of the right operand, and otherwise by the
5274 -- largest value of the right operand.
5276 if Hi_Left
< Ureal_0
then
5277 Hir
:= Round_Machine
(Hi_Left
/ Lo_Right
);
5279 Hir
:= Round_Machine
(Hi_Left
/ Hi_Right
);
5287 when N_Type_Conversion
=>
5289 -- For type conversion from one floating-point type to another, we
5290 -- can refine the range using the converted value.
5292 if Is_Floating_Point_Type
(Etype
(Expression
(N
))) then
5293 Determine_Range_R
(Expression
(N
), OK1
, Lor
, Hir
, Assume_Valid
);
5295 -- When converting an integer to a floating-point type, determine
5296 -- the range in integer first, and then convert the bounds.
5298 elsif Is_Discrete_Type
(Etype
(Expression
(N
))) then
5305 (Expression
(N
), OK1
, Lor_Int
, Hir_Int
, Assume_Valid
);
5308 Lor
:= Round_Machine
(UR_From_Uint
(Lor_Int
));
5309 Hir
:= Round_Machine
(UR_From_Uint
(Hir_Int
));
5317 -- Nothing special to do for all other expression kinds
5325 -- At this stage, if OK1 is true, then we know that the actual result of
5326 -- the computed expression is in the range Lor .. Hir. We can use this
5327 -- to restrict the possible range of results.
5331 -- If the refined value of the low bound is greater than the type
5332 -- low bound, then reset it to the more restrictive value.
5338 -- Similarly, if the refined value of the high bound is less than the
5339 -- value so far, then reset it to the more restrictive value.
5346 -- Set cache entry for future call and we are all done
5348 Determine_Range_Cache_N
(Cindex
) := N
;
5349 Determine_Range_Cache_V
(Cindex
) := Assume_Valid
;
5350 Determine_Range_Cache_Lo_R
(Cindex
) := Lo
;
5351 Determine_Range_Cache_Hi_R
(Cindex
) := Hi
;
5354 -- If any exception occurs, it means that we have some bug in the compiler,
5355 -- possibly triggered by a previous error, or by some unforeseen peculiar
5356 -- occurrence. However, this is only an optimization attempt, so there is
5357 -- really no point in crashing the compiler. Instead we just decide, too
5358 -- bad, we can't figure out a range in this case after all.
5363 -- Debug flag K disables this behavior (useful for debugging)
5365 if Debug_Flag_K
then
5373 end Determine_Range_R
;
5375 ------------------------------------
5376 -- Discriminant_Checks_Suppressed --
5377 ------------------------------------
5379 function Discriminant_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5382 if Is_Unchecked_Union
(E
) then
5384 elsif Checks_May_Be_Suppressed
(E
) then
5385 return Is_Check_Suppressed
(E
, Discriminant_Check
);
5389 return Scope_Suppress
.Suppress
(Discriminant_Check
);
5390 end Discriminant_Checks_Suppressed
;
5392 --------------------------------
5393 -- Division_Checks_Suppressed --
5394 --------------------------------
5396 function Division_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5398 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
5399 return Is_Check_Suppressed
(E
, Division_Check
);
5401 return Scope_Suppress
.Suppress
(Division_Check
);
5403 end Division_Checks_Suppressed
;
5405 --------------------------------------
5406 -- Duplicated_Tag_Checks_Suppressed --
5407 --------------------------------------
5409 function Duplicated_Tag_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5411 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
5412 return Is_Check_Suppressed
(E
, Duplicated_Tag_Check
);
5414 return Scope_Suppress
.Suppress
(Duplicated_Tag_Check
);
5416 end Duplicated_Tag_Checks_Suppressed
;
5418 -----------------------------------
5419 -- Elaboration_Checks_Suppressed --
5420 -----------------------------------
5422 function Elaboration_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5424 -- The complication in this routine is that if we are in the dynamic
5425 -- model of elaboration, we also check All_Checks, since All_Checks
5426 -- does not set Elaboration_Check explicitly.
5429 if Kill_Elaboration_Checks
(E
) then
5432 elsif Checks_May_Be_Suppressed
(E
) then
5433 if Is_Check_Suppressed
(E
, Elaboration_Check
) then
5436 elsif Dynamic_Elaboration_Checks
then
5437 return Is_Check_Suppressed
(E
, All_Checks
);
5445 if Scope_Suppress
.Suppress
(Elaboration_Check
) then
5448 elsif Dynamic_Elaboration_Checks
then
5449 return Scope_Suppress
.Suppress
(All_Checks
);
5454 end Elaboration_Checks_Suppressed
;
5456 ---------------------------
5457 -- Enable_Overflow_Check --
5458 ---------------------------
5460 procedure Enable_Overflow_Check
(N
: Node_Id
) is
5461 Typ
: constant Entity_Id
:= Base_Type
(Etype
(N
));
5462 Mode
: constant Overflow_Mode_Type
:= Overflow_Check_Mode
;
5470 Do_Ovflow_Check
: Boolean;
5473 if Debug_Flag_CC
then
5474 w
("Enable_Overflow_Check for node ", Int
(N
));
5475 Write_Str
(" Source location = ");
5480 -- No check if overflow checks suppressed for type of node
5482 if Overflow_Checks_Suppressed
(Etype
(N
)) then
5485 -- Nothing to do for unsigned integer types, which do not overflow
5487 elsif Is_Modular_Integer_Type
(Typ
) then
5491 -- This is the point at which processing for STRICT mode diverges
5492 -- from processing for MINIMIZED/ELIMINATED modes. This divergence is
5493 -- probably more extreme that it needs to be, but what is going on here
5494 -- is that when we introduced MINIMIZED/ELIMINATED modes, we wanted
5495 -- to leave the processing for STRICT mode untouched. There were
5496 -- two reasons for this. First it avoided any incompatible change of
5497 -- behavior. Second, it guaranteed that STRICT mode continued to be
5500 -- The big difference is that in STRICT mode there is a fair amount of
5501 -- circuitry to try to avoid setting the Do_Overflow_Check flag if we
5502 -- know that no check is needed. We skip all that in the two new modes,
5503 -- since really overflow checking happens over a whole subtree, and we
5504 -- do the corresponding optimizations later on when applying the checks.
5506 if Mode
in Minimized_Or_Eliminated
then
5507 if not (Overflow_Checks_Suppressed
(Etype
(N
)))
5508 and then not (Is_Entity_Name
(N
)
5509 and then Overflow_Checks_Suppressed
(Entity
(N
)))
5511 Activate_Overflow_Check
(N
);
5514 if Debug_Flag_CC
then
5515 w
("Minimized/Eliminated mode");
5521 -- Remainder of processing is for STRICT case, and is unchanged from
5522 -- earlier versions preceding the addition of MINIMIZED/ELIMINATED.
5524 -- Nothing to do if the range of the result is known OK. We skip this
5525 -- for conversions, since the caller already did the check, and in any
5526 -- case the condition for deleting the check for a type conversion is
5529 if Nkind
(N
) /= N_Type_Conversion
then
5530 Determine_Range
(N
, OK
, Lo
, Hi
, Assume_Valid
=> True);
5532 -- Note in the test below that we assume that the range is not OK
5533 -- if a bound of the range is equal to that of the type. That's not
5534 -- quite accurate but we do this for the following reasons:
5536 -- a) The way that Determine_Range works, it will typically report
5537 -- the bounds of the value as being equal to the bounds of the
5538 -- type, because it either can't tell anything more precise, or
5539 -- does not think it is worth the effort to be more precise.
5541 -- b) It is very unusual to have a situation in which this would
5542 -- generate an unnecessary overflow check (an example would be
5543 -- a subtype with a range 0 .. Integer'Last - 1 to which the
5544 -- literal value one is added).
5546 -- c) The alternative is a lot of special casing in this routine
5547 -- which would partially duplicate Determine_Range processing.
5550 Do_Ovflow_Check
:= True;
5552 -- Note that the following checks are quite deliberately > and <
5553 -- rather than >= and <= as explained above.
5555 if Lo
> Expr_Value
(Type_Low_Bound
(Typ
))
5557 Hi
< Expr_Value
(Type_High_Bound
(Typ
))
5559 Do_Ovflow_Check
:= False;
5561 -- Despite the comments above, it is worth dealing specially with
5562 -- division specially. The only case where integer division can
5563 -- overflow is (largest negative number) / (-1). So we will do
5564 -- an extra range analysis to see if this is possible.
5566 elsif Nkind
(N
) = N_Op_Divide
then
5568 (Left_Opnd
(N
), OK
, Lo
, Hi
, Assume_Valid
=> True);
5570 if OK
and then Lo
> Expr_Value
(Type_Low_Bound
(Typ
)) then
5571 Do_Ovflow_Check
:= False;
5575 (Right_Opnd
(N
), OK
, Lo
, Hi
, Assume_Valid
=> True);
5577 if OK
and then (Lo
> Uint_Minus_1
5581 Do_Ovflow_Check
:= False;
5586 -- If no overflow check required, we are done
5588 if not Do_Ovflow_Check
then
5589 if Debug_Flag_CC
then
5590 w
("No overflow check required");
5598 -- If not in optimizing mode, set flag and we are done. We are also done
5599 -- (and just set the flag) if the type is not a discrete type, since it
5600 -- is not worth the effort to eliminate checks for other than discrete
5601 -- types. In addition, we take this same path if we have stored the
5602 -- maximum number of checks possible already (a very unlikely situation,
5603 -- but we do not want to blow up).
5605 if Optimization_Level
= 0
5606 or else not Is_Discrete_Type
(Etype
(N
))
5607 or else Num_Saved_Checks
= Saved_Checks
'Last
5609 Activate_Overflow_Check
(N
);
5611 if Debug_Flag_CC
then
5612 w
("Optimization off");
5618 -- Otherwise evaluate and check the expression
5623 Target_Type
=> Empty
,
5629 if Debug_Flag_CC
then
5630 w
("Called Find_Check");
5634 w
(" Check_Num = ", Chk
);
5635 w
(" Ent = ", Int
(Ent
));
5636 Write_Str
(" Ofs = ");
5641 -- If check is not of form to optimize, then set flag and we are done
5644 Activate_Overflow_Check
(N
);
5648 -- If check is already performed, then return without setting flag
5651 if Debug_Flag_CC
then
5652 w
("Check suppressed!");
5658 -- Here we will make a new entry for the new check
5660 Activate_Overflow_Check
(N
);
5661 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
5662 Saved_Checks
(Num_Saved_Checks
) :=
5667 Target_Type
=> Empty
);
5669 if Debug_Flag_CC
then
5670 w
("Make new entry, check number = ", Num_Saved_Checks
);
5671 w
(" Entity = ", Int
(Ent
));
5672 Write_Str
(" Offset = ");
5674 w
(" Check_Type = O");
5675 w
(" Target_Type = Empty");
5678 -- If we get an exception, then something went wrong, probably because of
5679 -- an error in the structure of the tree due to an incorrect program. Or
5680 -- it may be a bug in the optimization circuit. In either case the safest
5681 -- thing is simply to set the check flag unconditionally.
5685 Activate_Overflow_Check
(N
);
5687 if Debug_Flag_CC
then
5688 w
(" exception occurred, overflow flag set");
5692 end Enable_Overflow_Check
;
5694 ------------------------
5695 -- Enable_Range_Check --
5696 ------------------------
5698 procedure Enable_Range_Check
(N
: Node_Id
) is
5707 -- Return if unchecked type conversion with range check killed. In this
5708 -- case we never set the flag (that's what Kill_Range_Check is about).
5710 if Nkind
(N
) = N_Unchecked_Type_Conversion
5711 and then Kill_Range_Check
(N
)
5716 -- Do not set range check flag if parent is assignment statement or
5717 -- object declaration with Suppress_Assignment_Checks flag set
5719 if Nkind_In
(Parent
(N
), N_Assignment_Statement
, N_Object_Declaration
)
5720 and then Suppress_Assignment_Checks
(Parent
(N
))
5725 -- Check for various cases where we should suppress the range check
5727 -- No check if range checks suppressed for type of node
5729 if Present
(Etype
(N
)) and then Range_Checks_Suppressed
(Etype
(N
)) then
5732 -- No check if node is an entity name, and range checks are suppressed
5733 -- for this entity, or for the type of this entity.
5735 elsif Is_Entity_Name
(N
)
5736 and then (Range_Checks_Suppressed
(Entity
(N
))
5737 or else Range_Checks_Suppressed
(Etype
(Entity
(N
))))
5741 -- No checks if index of array, and index checks are suppressed for
5742 -- the array object or the type of the array.
5744 elsif Nkind
(Parent
(N
)) = N_Indexed_Component
then
5746 Pref
: constant Node_Id
:= Prefix
(Parent
(N
));
5748 if Is_Entity_Name
(Pref
)
5749 and then Index_Checks_Suppressed
(Entity
(Pref
))
5752 elsif Index_Checks_Suppressed
(Etype
(Pref
)) then
5758 -- Debug trace output
5760 if Debug_Flag_CC
then
5761 w
("Enable_Range_Check for node ", Int
(N
));
5762 Write_Str
(" Source location = ");
5767 -- If not in optimizing mode, set flag and we are done. We are also done
5768 -- (and just set the flag) if the type is not a discrete type, since it
5769 -- is not worth the effort to eliminate checks for other than discrete
5770 -- types. In addition, we take this same path if we have stored the
5771 -- maximum number of checks possible already (a very unlikely situation,
5772 -- but we do not want to blow up).
5774 if Optimization_Level
= 0
5775 or else No
(Etype
(N
))
5776 or else not Is_Discrete_Type
(Etype
(N
))
5777 or else Num_Saved_Checks
= Saved_Checks
'Last
5779 Activate_Range_Check
(N
);
5781 if Debug_Flag_CC
then
5782 w
("Optimization off");
5788 -- Otherwise find out the target type
5792 -- For assignment, use left side subtype
5794 if Nkind
(P
) = N_Assignment_Statement
5795 and then Expression
(P
) = N
5797 Ttyp
:= Etype
(Name
(P
));
5799 -- For indexed component, use subscript subtype
5801 elsif Nkind
(P
) = N_Indexed_Component
then
5808 Atyp
:= Etype
(Prefix
(P
));
5810 if Is_Access_Type
(Atyp
) then
5811 Atyp
:= Designated_Type
(Atyp
);
5813 -- If the prefix is an access to an unconstrained array,
5814 -- perform check unconditionally: it depends on the bounds of
5815 -- an object and we cannot currently recognize whether the test
5816 -- may be redundant.
5818 if not Is_Constrained
(Atyp
) then
5819 Activate_Range_Check
(N
);
5823 -- Ditto if prefix is simply an unconstrained array. We used
5824 -- to think this case was OK, if the prefix was not an explicit
5825 -- dereference, but we have now seen a case where this is not
5826 -- true, so it is safer to just suppress the optimization in this
5827 -- case. The back end is getting better at eliminating redundant
5828 -- checks in any case, so the loss won't be important.
5830 elsif Is_Array_Type
(Atyp
)
5831 and then not Is_Constrained
(Atyp
)
5833 Activate_Range_Check
(N
);
5837 Indx
:= First_Index
(Atyp
);
5838 Subs
:= First
(Expressions
(P
));
5841 Ttyp
:= Etype
(Indx
);
5850 -- For now, ignore all other cases, they are not so interesting
5853 if Debug_Flag_CC
then
5854 w
(" target type not found, flag set");
5857 Activate_Range_Check
(N
);
5861 -- Evaluate and check the expression
5866 Target_Type
=> Ttyp
,
5872 if Debug_Flag_CC
then
5873 w
("Called Find_Check");
5874 w
("Target_Typ = ", Int
(Ttyp
));
5878 w
(" Check_Num = ", Chk
);
5879 w
(" Ent = ", Int
(Ent
));
5880 Write_Str
(" Ofs = ");
5885 -- If check is not of form to optimize, then set flag and we are done
5888 if Debug_Flag_CC
then
5889 w
(" expression not of optimizable type, flag set");
5892 Activate_Range_Check
(N
);
5896 -- If check is already performed, then return without setting flag
5899 if Debug_Flag_CC
then
5900 w
("Check suppressed!");
5906 -- Here we will make a new entry for the new check
5908 Activate_Range_Check
(N
);
5909 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
5910 Saved_Checks
(Num_Saved_Checks
) :=
5915 Target_Type
=> Ttyp
);
5917 if Debug_Flag_CC
then
5918 w
("Make new entry, check number = ", Num_Saved_Checks
);
5919 w
(" Entity = ", Int
(Ent
));
5920 Write_Str
(" Offset = ");
5922 w
(" Check_Type = R");
5923 w
(" Target_Type = ", Int
(Ttyp
));
5924 pg
(Union_Id
(Ttyp
));
5927 -- If we get an exception, then something went wrong, probably because of
5928 -- an error in the structure of the tree due to an incorrect program. Or
5929 -- it may be a bug in the optimization circuit. In either case the safest
5930 -- thing is simply to set the check flag unconditionally.
5934 Activate_Range_Check
(N
);
5936 if Debug_Flag_CC
then
5937 w
(" exception occurred, range flag set");
5941 end Enable_Range_Check
;
5947 procedure Ensure_Valid
5949 Holes_OK
: Boolean := False;
5950 Related_Id
: Entity_Id
:= Empty
;
5951 Is_Low_Bound
: Boolean := False;
5952 Is_High_Bound
: Boolean := False)
5954 Typ
: constant Entity_Id
:= Etype
(Expr
);
5957 -- Ignore call if we are not doing any validity checking
5959 if not Validity_Checks_On
then
5962 -- Ignore call if range or validity checks suppressed on entity or type
5964 elsif Range_Or_Validity_Checks_Suppressed
(Expr
) then
5967 -- No check required if expression is from the expander, we assume the
5968 -- expander will generate whatever checks are needed. Note that this is
5969 -- not just an optimization, it avoids infinite recursions.
5971 -- Unchecked conversions must be checked, unless they are initialized
5972 -- scalar values, as in a component assignment in an init proc.
5974 -- In addition, we force a check if Force_Validity_Checks is set
5976 elsif not Comes_From_Source
(Expr
)
5978 (Nkind
(Expr
) = N_Identifier
5979 and then Present
(Renamed_Object
(Entity
(Expr
)))
5980 and then Comes_From_Source
(Renamed_Object
(Entity
(Expr
))))
5981 and then not Force_Validity_Checks
5982 and then (Nkind
(Expr
) /= N_Unchecked_Type_Conversion
5983 or else Kill_Range_Check
(Expr
))
5987 -- No check required if expression is known to have valid value
5989 elsif Expr_Known_Valid
(Expr
) then
5992 -- No check needed within a generated predicate function. Validity
5993 -- of input value will have been checked earlier.
5995 elsif Ekind
(Current_Scope
) = E_Function
5996 and then Is_Predicate_Function
(Current_Scope
)
6000 -- Ignore case of enumeration with holes where the flag is set not to
6001 -- worry about holes, since no special validity check is needed
6003 elsif Is_Enumeration_Type
(Typ
)
6004 and then Has_Non_Standard_Rep
(Typ
)
6009 -- No check required on the left-hand side of an assignment
6011 elsif Nkind
(Parent
(Expr
)) = N_Assignment_Statement
6012 and then Expr
= Name
(Parent
(Expr
))
6016 -- No check on a universal real constant. The context will eventually
6017 -- convert it to a machine number for some target type, or report an
6020 elsif Nkind
(Expr
) = N_Real_Literal
6021 and then Etype
(Expr
) = Universal_Real
6025 -- If the expression denotes a component of a packed boolean array,
6026 -- no possible check applies. We ignore the old ACATS chestnuts that
6027 -- involve Boolean range True..True.
6029 -- Note: validity checks are generated for expressions that yield a
6030 -- scalar type, when it is possible to create a value that is outside of
6031 -- the type. If this is a one-bit boolean no such value exists. This is
6032 -- an optimization, and it also prevents compiler blowing up during the
6033 -- elaboration of improperly expanded packed array references.
6035 elsif Nkind
(Expr
) = N_Indexed_Component
6036 and then Is_Bit_Packed_Array
(Etype
(Prefix
(Expr
)))
6037 and then Root_Type
(Etype
(Expr
)) = Standard_Boolean
6041 -- For an expression with actions, we want to insert the validity check
6042 -- on the final Expression.
6044 elsif Nkind
(Expr
) = N_Expression_With_Actions
then
6045 Ensure_Valid
(Expression
(Expr
));
6048 -- An annoying special case. If this is an out parameter of a scalar
6049 -- type, then the value is not going to be accessed, therefore it is
6050 -- inappropriate to do any validity check at the call site.
6053 -- Only need to worry about scalar types
6055 if Is_Scalar_Type
(Typ
) then
6065 -- Find actual argument (which may be a parameter association)
6066 -- and the parent of the actual argument (the call statement)
6071 if Nkind
(P
) = N_Parameter_Association
then
6076 -- Only need to worry if we are argument of a procedure call
6077 -- since functions don't have out parameters. If this is an
6078 -- indirect or dispatching call, get signature from the
6081 if Nkind
(P
) = N_Procedure_Call_Statement
then
6082 L
:= Parameter_Associations
(P
);
6084 if Is_Entity_Name
(Name
(P
)) then
6085 E
:= Entity
(Name
(P
));
6087 pragma Assert
(Nkind
(Name
(P
)) = N_Explicit_Dereference
);
6088 E
:= Etype
(Name
(P
));
6091 -- Only need to worry if there are indeed actuals, and if
6092 -- this could be a procedure call, otherwise we cannot get a
6093 -- match (either we are not an argument, or the mode of the
6094 -- formal is not OUT). This test also filters out the
6097 if Is_Non_Empty_List
(L
) and then Is_Subprogram
(E
) then
6099 -- This is the loop through parameters, looking for an
6100 -- OUT parameter for which we are the argument.
6102 F
:= First_Formal
(E
);
6104 while Present
(F
) loop
6105 if Ekind
(F
) = E_Out_Parameter
and then A
= N
then
6118 -- If this is a boolean expression, only its elementary operands need
6119 -- checking: if they are valid, a boolean or short-circuit operation
6120 -- with them will be valid as well.
6122 if Base_Type
(Typ
) = Standard_Boolean
6124 (Nkind
(Expr
) in N_Op
or else Nkind
(Expr
) in N_Short_Circuit
)
6129 -- If we fall through, a validity check is required
6131 Insert_Valid_Check
(Expr
, Related_Id
, Is_Low_Bound
, Is_High_Bound
);
6133 if Is_Entity_Name
(Expr
)
6134 and then Safe_To_Capture_Value
(Expr
, Entity
(Expr
))
6136 Set_Is_Known_Valid
(Entity
(Expr
));
6140 ----------------------
6141 -- Expr_Known_Valid --
6142 ----------------------
6144 function Expr_Known_Valid
(Expr
: Node_Id
) return Boolean is
6145 Typ
: constant Entity_Id
:= Etype
(Expr
);
6148 -- Non-scalar types are always considered valid, since they never give
6149 -- rise to the issues of erroneous or bounded error behavior that are
6150 -- the concern. In formal reference manual terms the notion of validity
6151 -- only applies to scalar types. Note that even when packed arrays are
6152 -- represented using modular types, they are still arrays semantically,
6153 -- so they are also always valid (in particular, the unused bits can be
6154 -- random rubbish without affecting the validity of the array value).
6156 if not Is_Scalar_Type
(Typ
) or else Is_Packed_Array_Impl_Type
(Typ
) then
6159 -- If no validity checking, then everything is considered valid
6161 elsif not Validity_Checks_On
then
6164 -- Floating-point types are considered valid unless floating-point
6165 -- validity checks have been specifically turned on.
6167 elsif Is_Floating_Point_Type
(Typ
)
6168 and then not Validity_Check_Floating_Point
6172 -- If the expression is the value of an object that is known to be
6173 -- valid, then clearly the expression value itself is valid.
6175 elsif Is_Entity_Name
(Expr
)
6176 and then Is_Known_Valid
(Entity
(Expr
))
6178 -- Exclude volatile variables
6180 and then not Treat_As_Volatile
(Entity
(Expr
))
6184 -- References to discriminants are always considered valid. The value
6185 -- of a discriminant gets checked when the object is built. Within the
6186 -- record, we consider it valid, and it is important to do so, since
6187 -- otherwise we can try to generate bogus validity checks which
6188 -- reference discriminants out of scope. Discriminants of concurrent
6189 -- types are excluded for the same reason.
6191 elsif Is_Entity_Name
(Expr
)
6192 and then Denotes_Discriminant
(Expr
, Check_Concurrent
=> True)
6196 -- If the type is one for which all values are known valid, then we are
6197 -- sure that the value is valid except in the slightly odd case where
6198 -- the expression is a reference to a variable whose size has been
6199 -- explicitly set to a value greater than the object size.
6201 elsif Is_Known_Valid
(Typ
) then
6202 if Is_Entity_Name
(Expr
)
6203 and then Ekind
(Entity
(Expr
)) = E_Variable
6204 and then Esize
(Entity
(Expr
)) > Esize
(Typ
)
6211 -- Integer and character literals always have valid values, where
6212 -- appropriate these will be range checked in any case.
6214 elsif Nkind_In
(Expr
, N_Integer_Literal
, N_Character_Literal
) then
6217 -- If we have a type conversion or a qualification of a known valid
6218 -- value, then the result will always be valid.
6220 elsif Nkind_In
(Expr
, N_Type_Conversion
, N_Qualified_Expression
) then
6221 return Expr_Known_Valid
(Expression
(Expr
));
6223 -- Case of expression is a non-floating-point operator. In this case we
6224 -- can assume the result is valid the generated code for the operator
6225 -- will include whatever checks are needed (e.g. range checks) to ensure
6226 -- validity. This assumption does not hold for the floating-point case,
6227 -- since floating-point operators can generate Infinite or NaN results
6228 -- which are considered invalid.
6230 -- Historical note: in older versions, the exemption of floating-point
6231 -- types from this assumption was done only in cases where the parent
6232 -- was an assignment, function call or parameter association. Presumably
6233 -- the idea was that in other contexts, the result would be checked
6234 -- elsewhere, but this list of cases was missing tests (at least the
6235 -- N_Object_Declaration case, as shown by a reported missing validity
6236 -- check), and it is not clear why function calls but not procedure
6237 -- calls were tested for. It really seems more accurate and much
6238 -- safer to recognize that expressions which are the result of a
6239 -- floating-point operator can never be assumed to be valid.
6241 elsif Nkind
(Expr
) in N_Op
and then not Is_Floating_Point_Type
(Typ
) then
6244 -- The result of a membership test is always valid, since it is true or
6245 -- false, there are no other possibilities.
6247 elsif Nkind
(Expr
) in N_Membership_Test
then
6250 -- For all other cases, we do not know the expression is valid
6255 end Expr_Known_Valid
;
6261 procedure Find_Check
6263 Check_Type
: Character;
6264 Target_Type
: Entity_Id
;
6265 Entry_OK
: out Boolean;
6266 Check_Num
: out Nat
;
6267 Ent
: out Entity_Id
;
6270 function Within_Range_Of
6271 (Target_Type
: Entity_Id
;
6272 Check_Type
: Entity_Id
) return Boolean;
6273 -- Given a requirement for checking a range against Target_Type, and
6274 -- and a range Check_Type against which a check has already been made,
6275 -- determines if the check against check type is sufficient to ensure
6276 -- that no check against Target_Type is required.
6278 ---------------------
6279 -- Within_Range_Of --
6280 ---------------------
6282 function Within_Range_Of
6283 (Target_Type
: Entity_Id
;
6284 Check_Type
: Entity_Id
) return Boolean
6287 if Target_Type
= Check_Type
then
6292 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Type
);
6293 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Type
);
6294 Clo
: constant Node_Id
:= Type_Low_Bound
(Check_Type
);
6295 Chi
: constant Node_Id
:= Type_High_Bound
(Check_Type
);
6299 or else (Compile_Time_Known_Value
(Tlo
)
6301 Compile_Time_Known_Value
(Clo
)
6303 Expr_Value
(Clo
) >= Expr_Value
(Tlo
)))
6306 or else (Compile_Time_Known_Value
(Thi
)
6308 Compile_Time_Known_Value
(Chi
)
6310 Expr_Value
(Chi
) <= Expr_Value
(Clo
)))
6318 end Within_Range_Of
;
6320 -- Start of processing for Find_Check
6323 -- Establish default, in case no entry is found
6327 -- Case of expression is simple entity reference
6329 if Is_Entity_Name
(Expr
) then
6330 Ent
:= Entity
(Expr
);
6333 -- Case of expression is entity + known constant
6335 elsif Nkind
(Expr
) = N_Op_Add
6336 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
6337 and then Is_Entity_Name
(Left_Opnd
(Expr
))
6339 Ent
:= Entity
(Left_Opnd
(Expr
));
6340 Ofs
:= Expr_Value
(Right_Opnd
(Expr
));
6342 -- Case of expression is entity - known constant
6344 elsif Nkind
(Expr
) = N_Op_Subtract
6345 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
6346 and then Is_Entity_Name
(Left_Opnd
(Expr
))
6348 Ent
:= Entity
(Left_Opnd
(Expr
));
6349 Ofs
:= UI_Negate
(Expr_Value
(Right_Opnd
(Expr
)));
6351 -- Any other expression is not of the right form
6360 -- Come here with expression of appropriate form, check if entity is an
6361 -- appropriate one for our purposes.
6363 if (Ekind
(Ent
) = E_Variable
6364 or else Is_Constant_Object
(Ent
))
6365 and then not Is_Library_Level_Entity
(Ent
)
6373 -- See if there is matching check already
6375 for J
in reverse 1 .. Num_Saved_Checks
loop
6377 SC
: Saved_Check
renames Saved_Checks
(J
);
6379 if SC
.Killed
= False
6380 and then SC
.Entity
= Ent
6381 and then SC
.Offset
= Ofs
6382 and then SC
.Check_Type
= Check_Type
6383 and then Within_Range_Of
(Target_Type
, SC
.Target_Type
)
6391 -- If we fall through entry was not found
6396 ---------------------------------
6397 -- Generate_Discriminant_Check --
6398 ---------------------------------
6400 -- Note: the code for this procedure is derived from the
6401 -- Emit_Discriminant_Check Routine in trans.c.
6403 procedure Generate_Discriminant_Check
(N
: Node_Id
) is
6404 Loc
: constant Source_Ptr
:= Sloc
(N
);
6405 Pref
: constant Node_Id
:= Prefix
(N
);
6406 Sel
: constant Node_Id
:= Selector_Name
(N
);
6408 Orig_Comp
: constant Entity_Id
:=
6409 Original_Record_Component
(Entity
(Sel
));
6410 -- The original component to be checked
6412 Discr_Fct
: constant Entity_Id
:=
6413 Discriminant_Checking_Func
(Orig_Comp
);
6414 -- The discriminant checking function
6417 -- One discriminant to be checked in the type
6419 Real_Discr
: Entity_Id
;
6420 -- Actual discriminant in the call
6422 Pref_Type
: Entity_Id
;
6423 -- Type of relevant prefix (ignoring private/access stuff)
6426 -- List of arguments for function call
6429 -- Keep track of the formal corresponding to the actual we build for
6430 -- each discriminant, in order to be able to perform the necessary type
6434 -- Selected component reference for checking function argument
6437 Pref_Type
:= Etype
(Pref
);
6439 -- Force evaluation of the prefix, so that it does not get evaluated
6440 -- twice (once for the check, once for the actual reference). Such a
6441 -- double evaluation is always a potential source of inefficiency, and
6442 -- is functionally incorrect in the volatile case, or when the prefix
6443 -- may have side effects. A nonvolatile entity or a component of a
6444 -- nonvolatile entity requires no evaluation.
6446 if Is_Entity_Name
(Pref
) then
6447 if Treat_As_Volatile
(Entity
(Pref
)) then
6448 Force_Evaluation
(Pref
, Name_Req
=> True);
6451 elsif Treat_As_Volatile
(Etype
(Pref
)) then
6452 Force_Evaluation
(Pref
, Name_Req
=> True);
6454 elsif Nkind
(Pref
) = N_Selected_Component
6455 and then Is_Entity_Name
(Prefix
(Pref
))
6460 Force_Evaluation
(Pref
, Name_Req
=> True);
6463 -- For a tagged type, use the scope of the original component to
6464 -- obtain the type, because ???
6466 if Is_Tagged_Type
(Scope
(Orig_Comp
)) then
6467 Pref_Type
:= Scope
(Orig_Comp
);
6469 -- For an untagged derived type, use the discriminants of the parent
6470 -- which have been renamed in the derivation, possibly by a one-to-many
6471 -- discriminant constraint. For untagged type, initially get the Etype
6475 if Is_Derived_Type
(Pref_Type
)
6476 and then Number_Discriminants
(Pref_Type
) /=
6477 Number_Discriminants
(Etype
(Base_Type
(Pref_Type
)))
6479 Pref_Type
:= Etype
(Base_Type
(Pref_Type
));
6483 -- We definitely should have a checking function, This routine should
6484 -- not be called if no discriminant checking function is present.
6486 pragma Assert
(Present
(Discr_Fct
));
6488 -- Create the list of the actual parameters for the call. This list
6489 -- is the list of the discriminant fields of the record expression to
6490 -- be discriminant checked.
6493 Formal
:= First_Formal
(Discr_Fct
);
6494 Discr
:= First_Discriminant
(Pref_Type
);
6495 while Present
(Discr
) loop
6497 -- If we have a corresponding discriminant field, and a parent
6498 -- subtype is present, then we want to use the corresponding
6499 -- discriminant since this is the one with the useful value.
6501 if Present
(Corresponding_Discriminant
(Discr
))
6502 and then Ekind
(Pref_Type
) = E_Record_Type
6503 and then Present
(Parent_Subtype
(Pref_Type
))
6505 Real_Discr
:= Corresponding_Discriminant
(Discr
);
6507 Real_Discr
:= Discr
;
6510 -- Construct the reference to the discriminant
6513 Make_Selected_Component
(Loc
,
6515 Unchecked_Convert_To
(Pref_Type
,
6516 Duplicate_Subexpr
(Pref
)),
6517 Selector_Name
=> New_Occurrence_Of
(Real_Discr
, Loc
));
6519 -- Manually analyze and resolve this selected component. We really
6520 -- want it just as it appears above, and do not want the expander
6521 -- playing discriminal games etc with this reference. Then we append
6522 -- the argument to the list we are gathering.
6524 Set_Etype
(Scomp
, Etype
(Real_Discr
));
6525 Set_Analyzed
(Scomp
, True);
6526 Append_To
(Args
, Convert_To
(Etype
(Formal
), Scomp
));
6528 Next_Formal_With_Extras
(Formal
);
6529 Next_Discriminant
(Discr
);
6532 -- Now build and insert the call
6535 Make_Raise_Constraint_Error
(Loc
,
6537 Make_Function_Call
(Loc
,
6538 Name
=> New_Occurrence_Of
(Discr_Fct
, Loc
),
6539 Parameter_Associations
=> Args
),
6540 Reason
=> CE_Discriminant_Check_Failed
));
6541 end Generate_Discriminant_Check
;
6543 ---------------------------
6544 -- Generate_Index_Checks --
6545 ---------------------------
6547 procedure Generate_Index_Checks
(N
: Node_Id
) is
6549 function Entity_Of_Prefix
return Entity_Id
;
6550 -- Returns the entity of the prefix of N (or Empty if not found)
6552 ----------------------
6553 -- Entity_Of_Prefix --
6554 ----------------------
6556 function Entity_Of_Prefix
return Entity_Id
is
6561 while not Is_Entity_Name
(P
) loop
6562 if not Nkind_In
(P
, N_Selected_Component
,
6563 N_Indexed_Component
)
6572 end Entity_Of_Prefix
;
6576 Loc
: constant Source_Ptr
:= Sloc
(N
);
6577 A
: constant Node_Id
:= Prefix
(N
);
6578 A_Ent
: constant Entity_Id
:= Entity_Of_Prefix
;
6581 -- Start of processing for Generate_Index_Checks
6584 -- Ignore call if the prefix is not an array since we have a serious
6585 -- error in the sources. Ignore it also if index checks are suppressed
6586 -- for array object or type.
6588 if not Is_Array_Type
(Etype
(A
))
6589 or else (Present
(A_Ent
) and then Index_Checks_Suppressed
(A_Ent
))
6590 or else Index_Checks_Suppressed
(Etype
(A
))
6594 -- The indexed component we are dealing with contains 'Loop_Entry in its
6595 -- prefix. This case arises when analysis has determined that constructs
6598 -- Prefix'Loop_Entry (Expr)
6599 -- Prefix'Loop_Entry (Expr1, Expr2, ... ExprN)
6601 -- require rewriting for error detection purposes. A side effect of this
6602 -- action is the generation of index checks that mention 'Loop_Entry.
6603 -- Delay the generation of the check until 'Loop_Entry has been properly
6604 -- expanded. This is done in Expand_Loop_Entry_Attributes.
6606 elsif Nkind
(Prefix
(N
)) = N_Attribute_Reference
6607 and then Attribute_Name
(Prefix
(N
)) = Name_Loop_Entry
6612 -- Generate a raise of constraint error with the appropriate reason and
6613 -- a condition of the form:
6615 -- Base_Type (Sub) not in Array'Range (Subscript)
6617 -- Note that the reason we generate the conversion to the base type here
6618 -- is that we definitely want the range check to take place, even if it
6619 -- looks like the subtype is OK. Optimization considerations that allow
6620 -- us to omit the check have already been taken into account in the
6621 -- setting of the Do_Range_Check flag earlier on.
6623 Sub
:= First
(Expressions
(N
));
6625 -- Handle string literals
6627 if Ekind
(Etype
(A
)) = E_String_Literal_Subtype
then
6628 if Do_Range_Check
(Sub
) then
6629 Set_Do_Range_Check
(Sub
, False);
6631 -- For string literals we obtain the bounds of the string from the
6632 -- associated subtype.
6635 Make_Raise_Constraint_Error
(Loc
,
6639 Convert_To
(Base_Type
(Etype
(Sub
)),
6640 Duplicate_Subexpr_Move_Checks
(Sub
)),
6642 Make_Attribute_Reference
(Loc
,
6643 Prefix
=> New_Occurrence_Of
(Etype
(A
), Loc
),
6644 Attribute_Name
=> Name_Range
)),
6645 Reason
=> CE_Index_Check_Failed
));
6652 A_Idx
: Node_Id
:= Empty
;
6659 A_Idx
:= First_Index
(Etype
(A
));
6661 while Present
(Sub
) loop
6662 if Do_Range_Check
(Sub
) then
6663 Set_Do_Range_Check
(Sub
, False);
6665 -- Force evaluation except for the case of a simple name of
6666 -- a nonvolatile entity.
6668 if not Is_Entity_Name
(Sub
)
6669 or else Treat_As_Volatile
(Entity
(Sub
))
6671 Force_Evaluation
(Sub
);
6674 if Nkind
(A_Idx
) = N_Range
then
6677 elsif Nkind
(A_Idx
) = N_Identifier
6678 or else Nkind
(A_Idx
) = N_Expanded_Name
6680 A_Range
:= Scalar_Range
(Entity
(A_Idx
));
6682 else pragma Assert
(Nkind
(A_Idx
) = N_Subtype_Indication
);
6683 A_Range
:= Range_Expression
(Constraint
(A_Idx
));
6686 -- For array objects with constant bounds we can generate
6687 -- the index check using the bounds of the type of the index
6690 and then Ekind
(A_Ent
) = E_Variable
6691 and then Is_Constant_Bound
(Low_Bound
(A_Range
))
6692 and then Is_Constant_Bound
(High_Bound
(A_Range
))
6695 Make_Attribute_Reference
(Loc
,
6697 New_Occurrence_Of
(Etype
(A_Idx
), Loc
),
6698 Attribute_Name
=> Name_Range
);
6700 -- For arrays with non-constant bounds we cannot generate
6701 -- the index check using the bounds of the type of the index
6702 -- since it may reference discriminants of some enclosing
6703 -- type. We obtain the bounds directly from the prefix
6710 Num
:= New_List
(Make_Integer_Literal
(Loc
, Ind
));
6714 Make_Attribute_Reference
(Loc
,
6716 Duplicate_Subexpr_Move_Checks
(A
, Name_Req
=> True),
6717 Attribute_Name
=> Name_Range
,
6718 Expressions
=> Num
);
6722 Make_Raise_Constraint_Error
(Loc
,
6726 Convert_To
(Base_Type
(Etype
(Sub
)),
6727 Duplicate_Subexpr_Move_Checks
(Sub
)),
6728 Right_Opnd
=> Range_N
),
6729 Reason
=> CE_Index_Check_Failed
));
6732 A_Idx
:= Next_Index
(A_Idx
);
6738 end Generate_Index_Checks
;
6740 --------------------------
6741 -- Generate_Range_Check --
6742 --------------------------
6744 procedure Generate_Range_Check
6746 Target_Type
: Entity_Id
;
6747 Reason
: RT_Exception_Code
)
6749 Loc
: constant Source_Ptr
:= Sloc
(N
);
6750 Source_Type
: constant Entity_Id
:= Etype
(N
);
6751 Source_Base_Type
: constant Entity_Id
:= Base_Type
(Source_Type
);
6752 Target_Base_Type
: constant Entity_Id
:= Base_Type
(Target_Type
);
6754 procedure Convert_And_Check_Range
;
6755 -- Convert the conversion operand to the target base type and save in
6756 -- a temporary. Then check the converted value against the range of the
6759 -----------------------------
6760 -- Convert_And_Check_Range --
6761 -----------------------------
6763 procedure Convert_And_Check_Range
is
6764 Tnn
: constant Entity_Id
:= Make_Temporary
(Loc
, 'T', N
);
6767 -- We make a temporary to hold the value of the converted value
6768 -- (converted to the base type), and then do the test against this
6769 -- temporary. The conversion itself is replaced by an occurrence of
6770 -- Tnn and followed by the explicit range check. Note that checks
6771 -- are suppressed for this code, since we don't want a recursive
6772 -- range check popping up.
6774 -- Tnn : constant Target_Base_Type := Target_Base_Type (N);
6775 -- [constraint_error when Tnn not in Target_Type]
6777 Insert_Actions
(N
, New_List
(
6778 Make_Object_Declaration
(Loc
,
6779 Defining_Identifier
=> Tnn
,
6780 Object_Definition
=> New_Occurrence_Of
(Target_Base_Type
, Loc
),
6781 Constant_Present
=> True,
6783 Make_Type_Conversion
(Loc
,
6784 Subtype_Mark
=> New_Occurrence_Of
(Target_Base_Type
, Loc
),
6785 Expression
=> Duplicate_Subexpr
(N
))),
6787 Make_Raise_Constraint_Error
(Loc
,
6790 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
6791 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
6793 Suppress
=> All_Checks
);
6795 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
6797 -- Set the type of N, because the declaration for Tnn might not
6798 -- be analyzed yet, as is the case if N appears within a record
6799 -- declaration, as a discriminant constraint or expression.
6801 Set_Etype
(N
, Target_Base_Type
);
6802 end Convert_And_Check_Range
;
6804 -- Start of processing for Generate_Range_Check
6807 -- First special case, if the source type is already within the range
6808 -- of the target type, then no check is needed (probably we should have
6809 -- stopped Do_Range_Check from being set in the first place, but better
6810 -- late than never in preventing junk code and junk flag settings.
6812 if In_Subrange_Of
(Source_Type
, Target_Type
)
6814 -- We do NOT apply this if the source node is a literal, since in this
6815 -- case the literal has already been labeled as having the subtype of
6819 (Nkind_In
(N
, N_Integer_Literal
, N_Real_Literal
, N_Character_Literal
)
6822 and then Ekind
(Entity
(N
)) = E_Enumeration_Literal
))
6824 Set_Do_Range_Check
(N
, False);
6828 -- Here a check is needed. If the expander is not active, or if we are
6829 -- in GNATProve mode, then simply set the Do_Range_Check flag and we
6830 -- are done. In both these cases, we just want to see the range check
6831 -- flag set, we do not want to generate the explicit range check code.
6833 if GNATprove_Mode
or else not Expander_Active
then
6834 Set_Do_Range_Check
(N
, True);
6838 -- Here we will generate an explicit range check, so we don't want to
6839 -- set the Do_Range check flag, since the range check is taken care of
6840 -- by the code we will generate.
6842 Set_Do_Range_Check
(N
, False);
6844 -- Force evaluation of the node, so that it does not get evaluated twice
6845 -- (once for the check, once for the actual reference). Such a double
6846 -- evaluation is always a potential source of inefficiency, and is
6847 -- functionally incorrect in the volatile case.
6849 -- We skip the evaluation of attribute references because, after these
6850 -- runtime checks are generated, the expander may need to rewrite this
6851 -- node (for example, see Attribute_Max_Size_In_Storage_Elements in
6852 -- Expand_N_Attribute_Reference).
6854 if Nkind
(N
) /= N_Attribute_Reference
6855 and then (not Is_Entity_Name
(N
)
6856 or else Treat_As_Volatile
(Entity
(N
)))
6858 Force_Evaluation
(N
, Mode
=> Strict
);
6861 -- The easiest case is when Source_Base_Type and Target_Base_Type are
6862 -- the same since in this case we can simply do a direct check of the
6863 -- value of N against the bounds of Target_Type.
6865 -- [constraint_error when N not in Target_Type]
6867 -- Note: this is by far the most common case, for example all cases of
6868 -- checks on the RHS of assignments are in this category, but not all
6869 -- cases are like this. Notably conversions can involve two types.
6871 if Source_Base_Type
= Target_Base_Type
then
6873 -- Insert the explicit range check. Note that we suppress checks for
6874 -- this code, since we don't want a recursive range check popping up.
6877 Make_Raise_Constraint_Error
(Loc
,
6880 Left_Opnd
=> Duplicate_Subexpr
(N
),
6881 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
6883 Suppress
=> All_Checks
);
6885 -- Next test for the case where the target type is within the bounds
6886 -- of the base type of the source type, since in this case we can
6887 -- simply convert these bounds to the base type of T to do the test.
6889 -- [constraint_error when N not in
6890 -- Source_Base_Type (Target_Type'First)
6892 -- Source_Base_Type(Target_Type'Last))]
6894 -- The conversions will always work and need no check
6896 -- Unchecked_Convert_To is used instead of Convert_To to handle the case
6897 -- of converting from an enumeration value to an integer type, such as
6898 -- occurs for the case of generating a range check on Enum'Val(Exp)
6899 -- (which used to be handled by gigi). This is OK, since the conversion
6900 -- itself does not require a check.
6902 elsif In_Subrange_Of
(Target_Type
, Source_Base_Type
) then
6904 -- Insert the explicit range check. Note that we suppress checks for
6905 -- this code, since we don't want a recursive range check popping up.
6907 if Is_Discrete_Type
(Source_Base_Type
)
6909 Is_Discrete_Type
(Target_Base_Type
)
6912 Make_Raise_Constraint_Error
(Loc
,
6915 Left_Opnd
=> Duplicate_Subexpr
(N
),
6920 Unchecked_Convert_To
(Source_Base_Type
,
6921 Make_Attribute_Reference
(Loc
,
6923 New_Occurrence_Of
(Target_Type
, Loc
),
6924 Attribute_Name
=> Name_First
)),
6927 Unchecked_Convert_To
(Source_Base_Type
,
6928 Make_Attribute_Reference
(Loc
,
6930 New_Occurrence_Of
(Target_Type
, Loc
),
6931 Attribute_Name
=> Name_Last
)))),
6933 Suppress
=> All_Checks
);
6935 -- For conversions involving at least one type that is not discrete,
6936 -- first convert to target type and then generate the range check.
6937 -- This avoids problems with values that are close to a bound of the
6938 -- target type that would fail a range check when done in a larger
6939 -- source type before converting but would pass if converted with
6940 -- rounding and then checked (such as in float-to-float conversions).
6943 Convert_And_Check_Range
;
6946 -- Note that at this stage we now that the Target_Base_Type is not in
6947 -- the range of the Source_Base_Type (since even the Target_Type itself
6948 -- is not in this range). It could still be the case that Source_Type is
6949 -- in range of the target base type since we have not checked that case.
6951 -- If that is the case, we can freely convert the source to the target,
6952 -- and then test the target result against the bounds.
6954 elsif In_Subrange_Of
(Source_Type
, Target_Base_Type
) then
6955 Convert_And_Check_Range
;
6957 -- At this stage, we know that we have two scalar types, which are
6958 -- directly convertible, and where neither scalar type has a base
6959 -- range that is in the range of the other scalar type.
6961 -- The only way this can happen is with a signed and unsigned type.
6962 -- So test for these two cases:
6965 -- Case of the source is unsigned and the target is signed
6967 if Is_Unsigned_Type
(Source_Base_Type
)
6968 and then not Is_Unsigned_Type
(Target_Base_Type
)
6970 -- If the source is unsigned and the target is signed, then we
6971 -- know that the source is not shorter than the target (otherwise
6972 -- the source base type would be in the target base type range).
6974 -- In other words, the unsigned type is either the same size as
6975 -- the target, or it is larger. It cannot be smaller.
6978 (Esize
(Source_Base_Type
) >= Esize
(Target_Base_Type
));
6980 -- We only need to check the low bound if the low bound of the
6981 -- target type is non-negative. If the low bound of the target
6982 -- type is negative, then we know that we will fit fine.
6984 -- If the high bound of the target type is negative, then we
6985 -- know we have a constraint error, since we can't possibly
6986 -- have a negative source.
6988 -- With these two checks out of the way, we can do the check
6989 -- using the source type safely
6991 -- This is definitely the most annoying case.
6993 -- [constraint_error
6994 -- when (Target_Type'First >= 0
6996 -- N < Source_Base_Type (Target_Type'First))
6997 -- or else Target_Type'Last < 0
6998 -- or else N > Source_Base_Type (Target_Type'Last)];
7000 -- We turn off all checks since we know that the conversions
7001 -- will work fine, given the guards for negative values.
7004 Make_Raise_Constraint_Error
(Loc
,
7010 Left_Opnd
=> Make_Op_Ge
(Loc
,
7012 Make_Attribute_Reference
(Loc
,
7014 New_Occurrence_Of
(Target_Type
, Loc
),
7015 Attribute_Name
=> Name_First
),
7016 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
7020 Left_Opnd
=> Duplicate_Subexpr
(N
),
7022 Convert_To
(Source_Base_Type
,
7023 Make_Attribute_Reference
(Loc
,
7025 New_Occurrence_Of
(Target_Type
, Loc
),
7026 Attribute_Name
=> Name_First
)))),
7031 Make_Attribute_Reference
(Loc
,
7032 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
7033 Attribute_Name
=> Name_Last
),
7034 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
))),
7038 Left_Opnd
=> Duplicate_Subexpr
(N
),
7040 Convert_To
(Source_Base_Type
,
7041 Make_Attribute_Reference
(Loc
,
7042 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
7043 Attribute_Name
=> Name_Last
)))),
7046 Suppress
=> All_Checks
);
7048 -- Only remaining possibility is that the source is signed and
7049 -- the target is unsigned.
7052 pragma Assert
(not Is_Unsigned_Type
(Source_Base_Type
)
7053 and then Is_Unsigned_Type
(Target_Base_Type
));
7055 -- If the source is signed and the target is unsigned, then we
7056 -- know that the target is not shorter than the source (otherwise
7057 -- the target base type would be in the source base type range).
7059 -- In other words, the unsigned type is either the same size as
7060 -- the target, or it is larger. It cannot be smaller.
7062 -- Clearly we have an error if the source value is negative since
7063 -- no unsigned type can have negative values. If the source type
7064 -- is non-negative, then the check can be done using the target
7067 -- Tnn : constant Target_Base_Type (N) := Target_Type;
7069 -- [constraint_error
7070 -- when N < 0 or else Tnn not in Target_Type];
7072 -- We turn off all checks for the conversion of N to the target
7073 -- base type, since we generate the explicit check to ensure that
7074 -- the value is non-negative
7077 Tnn
: constant Entity_Id
:= Make_Temporary
(Loc
, 'T', N
);
7080 Insert_Actions
(N
, New_List
(
7081 Make_Object_Declaration
(Loc
,
7082 Defining_Identifier
=> Tnn
,
7083 Object_Definition
=>
7084 New_Occurrence_Of
(Target_Base_Type
, Loc
),
7085 Constant_Present
=> True,
7087 Make_Unchecked_Type_Conversion
(Loc
,
7089 New_Occurrence_Of
(Target_Base_Type
, Loc
),
7090 Expression
=> Duplicate_Subexpr
(N
))),
7092 Make_Raise_Constraint_Error
(Loc
,
7097 Left_Opnd
=> Duplicate_Subexpr
(N
),
7098 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
7102 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
7104 New_Occurrence_Of
(Target_Type
, Loc
))),
7107 Suppress
=> All_Checks
);
7109 -- Set the Etype explicitly, because Insert_Actions may have
7110 -- placed the declaration in the freeze list for an enclosing
7111 -- construct, and thus it is not analyzed yet.
7113 Set_Etype
(Tnn
, Target_Base_Type
);
7114 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
7118 end Generate_Range_Check
;
7124 function Get_Check_Id
(N
: Name_Id
) return Check_Id
is
7126 -- For standard check name, we can do a direct computation
7128 if N
in First_Check_Name
.. Last_Check_Name
then
7129 return Check_Id
(N
- (First_Check_Name
- 1));
7131 -- For non-standard names added by pragma Check_Name, search table
7134 for J
in All_Checks
+ 1 .. Check_Names
.Last
loop
7135 if Check_Names
.Table
(J
) = N
then
7141 -- No matching name found
7146 ---------------------
7147 -- Get_Discriminal --
7148 ---------------------
7150 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
is
7151 Loc
: constant Source_Ptr
:= Sloc
(E
);
7156 -- The bound can be a bona fide parameter of a protected operation,
7157 -- rather than a prival encoded as an in-parameter.
7159 if No
(Discriminal_Link
(Entity
(Bound
))) then
7163 -- Climb the scope stack looking for an enclosing protected type. If
7164 -- we run out of scopes, return the bound itself.
7167 while Present
(Sc
) loop
7168 if Sc
= Standard_Standard
then
7170 elsif Ekind
(Sc
) = E_Protected_Type
then
7177 D
:= First_Discriminant
(Sc
);
7178 while Present
(D
) loop
7179 if Chars
(D
) = Chars
(Bound
) then
7180 return New_Occurrence_Of
(Discriminal
(D
), Loc
);
7183 Next_Discriminant
(D
);
7187 end Get_Discriminal
;
7189 ----------------------
7190 -- Get_Range_Checks --
7191 ----------------------
7193 function Get_Range_Checks
7195 Target_Typ
: Entity_Id
;
7196 Source_Typ
: Entity_Id
:= Empty
;
7197 Warn_Node
: Node_Id
:= Empty
) return Check_Result
7201 Selected_Range_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Warn_Node
);
7202 end Get_Range_Checks
;
7208 function Guard_Access
7211 Ck_Node
: Node_Id
) return Node_Id
7214 if Nkind
(Cond
) = N_Or_Else
then
7215 Set_Paren_Count
(Cond
, 1);
7218 if Nkind
(Ck_Node
) = N_Allocator
then
7226 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
7227 Right_Opnd
=> Make_Null
(Loc
)),
7228 Right_Opnd
=> Cond
);
7232 -----------------------------
7233 -- Index_Checks_Suppressed --
7234 -----------------------------
7236 function Index_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
7238 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
7239 return Is_Check_Suppressed
(E
, Index_Check
);
7241 return Scope_Suppress
.Suppress
(Index_Check
);
7243 end Index_Checks_Suppressed
;
7249 procedure Initialize
is
7251 for J
in Determine_Range_Cache_N
'Range loop
7252 Determine_Range_Cache_N
(J
) := Empty
;
7257 for J
in Int
range 1 .. All_Checks
loop
7258 Check_Names
.Append
(Name_Id
(Int
(First_Check_Name
) + J
- 1));
7262 -------------------------
7263 -- Insert_Range_Checks --
7264 -------------------------
7266 procedure Insert_Range_Checks
7267 (Checks
: Check_Result
;
7269 Suppress_Typ
: Entity_Id
;
7270 Static_Sloc
: Source_Ptr
:= No_Location
;
7271 Flag_Node
: Node_Id
:= Empty
;
7272 Do_Before
: Boolean := False)
7274 Checks_On
: constant Boolean :=
7275 not Index_Checks_Suppressed
(Suppress_Typ
)
7277 not Range_Checks_Suppressed
(Suppress_Typ
);
7279 Check_Node
: Node_Id
;
7280 Internal_Flag_Node
: Node_Id
:= Flag_Node
;
7281 Internal_Static_Sloc
: Source_Ptr
:= Static_Sloc
;
7284 -- For now we just return if Checks_On is false, however this should be
7285 -- enhanced to check for an always True value in the condition and to
7286 -- generate a compilation warning???
7288 if not Expander_Active
or not Checks_On
then
7292 if Static_Sloc
= No_Location
then
7293 Internal_Static_Sloc
:= Sloc
(Node
);
7296 if No
(Flag_Node
) then
7297 Internal_Flag_Node
:= Node
;
7300 for J
in 1 .. 2 loop
7301 exit when No
(Checks
(J
));
7303 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
7304 and then Present
(Condition
(Checks
(J
)))
7306 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
7307 Check_Node
:= Checks
(J
);
7308 Mark_Rewrite_Insertion
(Check_Node
);
7311 Insert_Before_And_Analyze
(Node
, Check_Node
);
7313 Insert_After_And_Analyze
(Node
, Check_Node
);
7316 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
7321 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
7322 Reason
=> CE_Range_Check_Failed
);
7323 Mark_Rewrite_Insertion
(Check_Node
);
7326 Insert_Before_And_Analyze
(Node
, Check_Node
);
7328 Insert_After_And_Analyze
(Node
, Check_Node
);
7332 end Insert_Range_Checks
;
7334 ------------------------
7335 -- Insert_Valid_Check --
7336 ------------------------
7338 procedure Insert_Valid_Check
7340 Related_Id
: Entity_Id
:= Empty
;
7341 Is_Low_Bound
: Boolean := False;
7342 Is_High_Bound
: Boolean := False)
7344 Loc
: constant Source_Ptr
:= Sloc
(Expr
);
7345 Typ
: constant Entity_Id
:= Etype
(Expr
);
7349 -- Do not insert if checks off, or if not checking validity or if
7350 -- expression is known to be valid.
7352 if not Validity_Checks_On
7353 or else Range_Or_Validity_Checks_Suppressed
(Expr
)
7354 or else Expr_Known_Valid
(Expr
)
7358 -- Do not insert checks within a predicate function. This will arise
7359 -- if the current unit and the predicate function are being compiled
7360 -- with validity checks enabled.
7362 elsif Present
(Predicate_Function
(Typ
))
7363 and then Current_Scope
= Predicate_Function
(Typ
)
7367 -- If the expression is a packed component of a modular type of the
7368 -- right size, the data is always valid.
7370 elsif Nkind
(Expr
) = N_Selected_Component
7371 and then Present
(Component_Clause
(Entity
(Selector_Name
(Expr
))))
7372 and then Is_Modular_Integer_Type
(Typ
)
7373 and then Modulus
(Typ
) = 2 ** Esize
(Entity
(Selector_Name
(Expr
)))
7377 -- Do not generate a validity check when inside a generic unit as this
7378 -- is an expansion activity.
7380 elsif Inside_A_Generic
then
7384 -- If we have a checked conversion, then validity check applies to
7385 -- the expression inside the conversion, not the result, since if
7386 -- the expression inside is valid, then so is the conversion result.
7389 while Nkind
(Exp
) = N_Type_Conversion
loop
7390 Exp
:= Expression
(Exp
);
7393 -- Do not generate a check for a variable which already validates the
7394 -- value of an assignable object.
7396 if Is_Validation_Variable_Reference
(Exp
) then
7406 -- If the expression denotes an assignable object, capture its value
7407 -- in a variable and replace the original expression by the variable.
7408 -- This approach has several effects:
7410 -- 1) The evaluation of the object results in only one read in the
7411 -- case where the object is atomic or volatile.
7413 -- Var ... := Object; -- read
7415 -- 2) The captured value is the one verified by attribute 'Valid.
7416 -- As a result the object is not evaluated again, which would
7417 -- result in an unwanted read in the case where the object is
7418 -- atomic or volatile.
7420 -- if not Var'Valid then -- OK, no read of Object
7422 -- if not Object'Valid then -- Wrong, extra read of Object
7424 -- 3) The captured value replaces the original object reference.
7425 -- As a result the object is not evaluated again, in the same
7428 -- ... Var ... -- OK, no read of Object
7430 -- ... Object ... -- Wrong, extra read of Object
7432 -- 4) The use of a variable to capture the value of the object
7433 -- allows the propagation of any changes back to the original
7436 -- procedure Call (Val : in out ...);
7438 -- Var : ... := Object; -- read Object
7439 -- if not Var'Valid then -- validity check
7440 -- Call (Var); -- modify Var
7441 -- Object := Var; -- update Object
7443 if Is_Variable
(Exp
) then
7444 Var_Id
:= Make_Temporary
(Loc
, 'T', Exp
);
7446 -- Because we could be dealing with a transient scope which would
7447 -- cause our object declaration to remain unanalyzed we must do
7448 -- some manual decoration.
7450 Set_Ekind
(Var_Id
, E_Variable
);
7451 Set_Etype
(Var_Id
, Typ
);
7454 Make_Object_Declaration
(Loc
,
7455 Defining_Identifier
=> Var_Id
,
7456 Object_Definition
=> New_Occurrence_Of
(Typ
, Loc
),
7457 Expression
=> New_Copy_Tree
(Exp
)),
7458 Suppress
=> Validity_Check
);
7460 Set_Validated_Object
(Var_Id
, New_Copy_Tree
(Exp
));
7461 Rewrite
(Exp
, New_Occurrence_Of
(Var_Id
, Loc
));
7462 PV
:= New_Occurrence_Of
(Var_Id
, Loc
);
7464 -- Copy the Do_Range_Check flag over to the new Exp, so it doesn't
7465 -- get lost. Floating point types are handled elsewhere.
7467 if not Is_Floating_Point_Type
(Typ
) then
7468 Set_Do_Range_Check
(Exp
, Do_Range_Check
(Original_Node
(Exp
)));
7471 -- Otherwise the expression does not denote a variable. Force its
7472 -- evaluation by capturing its value in a constant. Generate:
7474 -- Temp : constant ... := Exp;
7479 Related_Id
=> Related_Id
,
7480 Is_Low_Bound
=> Is_Low_Bound
,
7481 Is_High_Bound
=> Is_High_Bound
);
7483 PV
:= New_Copy_Tree
(Exp
);
7486 -- A rather specialized test. If PV is an analyzed expression which
7487 -- is an indexed component of a packed array that has not been
7488 -- properly expanded, turn off its Analyzed flag to make sure it
7489 -- gets properly reexpanded. If the prefix is an access value,
7490 -- the dereference will be added later.
7492 -- The reason this arises is that Duplicate_Subexpr_No_Checks did
7493 -- an analyze with the old parent pointer. This may point e.g. to
7494 -- a subprogram call, which deactivates this expansion.
7497 and then Nkind
(PV
) = N_Indexed_Component
7498 and then Is_Array_Type
(Etype
(Prefix
(PV
)))
7499 and then Present
(Packed_Array_Impl_Type
(Etype
(Prefix
(PV
))))
7501 Set_Analyzed
(PV
, False);
7504 -- Build the raise CE node to check for validity. We build a type
7505 -- qualification for the prefix, since it may not be of the form of
7506 -- a name, and we don't care in this context!
7509 Make_Raise_Constraint_Error
(Loc
,
7513 Make_Attribute_Reference
(Loc
,
7515 Attribute_Name
=> Name_Valid
)),
7516 Reason
=> CE_Invalid_Data
);
7518 -- Insert the validity check. Note that we do this with validity
7519 -- checks turned off, to avoid recursion, we do not want validity
7520 -- checks on the validity checking code itself.
7522 Insert_Action
(Expr
, CE
, Suppress
=> Validity_Check
);
7524 -- If the expression is a reference to an element of a bit-packed
7525 -- array, then it is rewritten as a renaming declaration. If the
7526 -- expression is an actual in a call, it has not been expanded,
7527 -- waiting for the proper point at which to do it. The same happens
7528 -- with renamings, so that we have to force the expansion now. This
7529 -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb
7532 if Is_Entity_Name
(Exp
)
7533 and then Nkind
(Parent
(Entity
(Exp
))) =
7534 N_Object_Renaming_Declaration
7537 Old_Exp
: constant Node_Id
:= Name
(Parent
(Entity
(Exp
)));
7539 if Nkind
(Old_Exp
) = N_Indexed_Component
7540 and then Is_Bit_Packed_Array
(Etype
(Prefix
(Old_Exp
)))
7542 Expand_Packed_Element_Reference
(Old_Exp
);
7547 end Insert_Valid_Check
;
7549 -------------------------------------
7550 -- Is_Signed_Integer_Arithmetic_Op --
7551 -------------------------------------
7553 function Is_Signed_Integer_Arithmetic_Op
(N
: Node_Id
) return Boolean is
7567 return Is_Signed_Integer_Type
(Etype
(N
));
7569 when N_Case_Expression
7572 return Is_Signed_Integer_Type
(Etype
(N
));
7577 end Is_Signed_Integer_Arithmetic_Op
;
7579 ----------------------------------
7580 -- Install_Null_Excluding_Check --
7581 ----------------------------------
7583 procedure Install_Null_Excluding_Check
(N
: Node_Id
) is
7584 Loc
: constant Source_Ptr
:= Sloc
(Parent
(N
));
7585 Typ
: constant Entity_Id
:= Etype
(N
);
7587 function Safe_To_Capture_In_Parameter_Value
return Boolean;
7588 -- Determines if it is safe to capture Known_Non_Null status for an
7589 -- the entity referenced by node N. The caller ensures that N is indeed
7590 -- an entity name. It is safe to capture the non-null status for an IN
7591 -- parameter when the reference occurs within a declaration that is sure
7592 -- to be executed as part of the declarative region.
7594 procedure Mark_Non_Null
;
7595 -- After installation of check, if the node in question is an entity
7596 -- name, then mark this entity as non-null if possible.
7598 function Safe_To_Capture_In_Parameter_Value
return Boolean is
7599 E
: constant Entity_Id
:= Entity
(N
);
7600 S
: constant Entity_Id
:= Current_Scope
;
7604 if Ekind
(E
) /= E_In_Parameter
then
7608 -- Two initial context checks. We must be inside a subprogram body
7609 -- with declarations and reference must not appear in nested scopes.
7611 if (Ekind
(S
) /= E_Function
and then Ekind
(S
) /= E_Procedure
)
7612 or else Scope
(E
) /= S
7617 S_Par
:= Parent
(Parent
(S
));
7619 if Nkind
(S_Par
) /= N_Subprogram_Body
7620 or else No
(Declarations
(S_Par
))
7630 -- Retrieve the declaration node of N (if any). Note that N
7631 -- may be a part of a complex initialization expression.
7635 while Present
(P
) loop
7637 -- If we have a short circuit form, and we are within the right
7638 -- hand expression, we return false, since the right hand side
7639 -- is not guaranteed to be elaborated.
7641 if Nkind
(P
) in N_Short_Circuit
7642 and then N
= Right_Opnd
(P
)
7647 -- Similarly, if we are in an if expression and not part of the
7648 -- condition, then we return False, since neither the THEN or
7649 -- ELSE dependent expressions will always be elaborated.
7651 if Nkind
(P
) = N_If_Expression
7652 and then N
/= First
(Expressions
(P
))
7657 -- If within a case expression, and not part of the expression,
7658 -- then return False, since a particular dependent expression
7659 -- may not always be elaborated
7661 if Nkind
(P
) = N_Case_Expression
7662 and then N
/= Expression
(P
)
7667 -- While traversing the parent chain, if node N belongs to a
7668 -- statement, then it may never appear in a declarative region.
7670 if Nkind
(P
) in N_Statement_Other_Than_Procedure_Call
7671 or else Nkind
(P
) = N_Procedure_Call_Statement
7676 -- If we are at a declaration, record it and exit
7678 if Nkind
(P
) in N_Declaration
7679 and then Nkind
(P
) not in N_Subprogram_Specification
7692 return List_Containing
(N_Decl
) = Declarations
(S_Par
);
7694 end Safe_To_Capture_In_Parameter_Value
;
7700 procedure Mark_Non_Null
is
7702 -- Only case of interest is if node N is an entity name
7704 if Is_Entity_Name
(N
) then
7706 -- For sure, we want to clear an indication that this is known to
7707 -- be null, since if we get past this check, it definitely is not.
7709 Set_Is_Known_Null
(Entity
(N
), False);
7711 -- We can mark the entity as known to be non-null if either it is
7712 -- safe to capture the value, or in the case of an IN parameter,
7713 -- which is a constant, if the check we just installed is in the
7714 -- declarative region of the subprogram body. In this latter case,
7715 -- a check is decisive for the rest of the body if the expression
7716 -- is sure to be elaborated, since we know we have to elaborate
7717 -- all declarations before executing the body.
7719 -- Couldn't this always be part of Safe_To_Capture_Value ???
7721 if Safe_To_Capture_Value
(N
, Entity
(N
))
7722 or else Safe_To_Capture_In_Parameter_Value
7724 Set_Is_Known_Non_Null
(Entity
(N
));
7729 -- Start of processing for Install_Null_Excluding_Check
7732 pragma Assert
(Is_Access_Type
(Typ
));
7734 -- No check inside a generic, check will be emitted in instance
7736 if Inside_A_Generic
then
7740 -- No check needed if known to be non-null
7742 if Known_Non_Null
(N
) then
7746 -- If known to be null, here is where we generate a compile time check
7748 if Known_Null
(N
) then
7750 -- Avoid generating warning message inside init procs. In SPARK mode
7751 -- we can go ahead and call Apply_Compile_Time_Constraint_Error
7752 -- since it will be turned into an error in any case.
7754 if (not Inside_Init_Proc
or else SPARK_Mode
= On
)
7756 -- Do not emit the warning within a conditional expression,
7757 -- where the expression might not be evaluated, and the warning
7758 -- appear as extraneous noise.
7760 and then not Within_Case_Or_If_Expression
(N
)
7762 Apply_Compile_Time_Constraint_Error
7763 (N
, "null value not allowed here??", CE_Access_Check_Failed
);
7765 -- Remaining cases, where we silently insert the raise
7769 Make_Raise_Constraint_Error
(Loc
,
7770 Reason
=> CE_Access_Check_Failed
));
7777 -- If entity is never assigned, for sure a warning is appropriate
7779 if Is_Entity_Name
(N
) then
7780 Check_Unset_Reference
(N
);
7783 -- No check needed if checks are suppressed on the range. Note that we
7784 -- don't set Is_Known_Non_Null in this case (we could legitimately do
7785 -- so, since the program is erroneous, but we don't like to casually
7786 -- propagate such conclusions from erroneosity).
7788 if Access_Checks_Suppressed
(Typ
) then
7792 -- No check needed for access to concurrent record types generated by
7793 -- the expander. This is not just an optimization (though it does indeed
7794 -- remove junk checks). It also avoids generation of junk warnings.
7796 if Nkind
(N
) in N_Has_Chars
7797 and then Chars
(N
) = Name_uObject
7798 and then Is_Concurrent_Record_Type
7799 (Directly_Designated_Type
(Etype
(N
)))
7804 -- No check needed in interface thunks since the runtime check is
7805 -- already performed at the caller side.
7807 if Is_Thunk
(Current_Scope
) then
7811 -- No check needed for the Get_Current_Excep.all.all idiom generated by
7812 -- the expander within exception handlers, since we know that the value
7813 -- can never be null.
7815 -- Is this really the right way to do this? Normally we generate such
7816 -- code in the expander with checks off, and that's how we suppress this
7817 -- kind of junk check ???
7819 if Nkind
(N
) = N_Function_Call
7820 and then Nkind
(Name
(N
)) = N_Explicit_Dereference
7821 and then Nkind
(Prefix
(Name
(N
))) = N_Identifier
7822 and then Is_RTE
(Entity
(Prefix
(Name
(N
))), RE_Get_Current_Excep
)
7827 -- Otherwise install access check
7830 Make_Raise_Constraint_Error
(Loc
,
7833 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(N
),
7834 Right_Opnd
=> Make_Null
(Loc
)),
7835 Reason
=> CE_Access_Check_Failed
));
7838 end Install_Null_Excluding_Check
;
7840 -----------------------------------------
7841 -- Install_Primitive_Elaboration_Check --
7842 -----------------------------------------
7844 procedure Install_Primitive_Elaboration_Check
(Subp_Body
: Node_Id
) is
7845 function Within_Compilation_Unit_Instance
7846 (Subp_Id
: Entity_Id
) return Boolean;
7847 -- Determine whether subprogram Subp_Id appears within an instance which
7848 -- acts as a compilation unit.
7850 --------------------------------------
7851 -- Within_Compilation_Unit_Instance --
7852 --------------------------------------
7854 function Within_Compilation_Unit_Instance
7855 (Subp_Id
: Entity_Id
) return Boolean
7860 -- Examine the scope chain looking for a compilation-unit-level
7863 Pack
:= Scope
(Subp_Id
);
7864 while Present
(Pack
) and then Pack
/= Standard_Standard
loop
7865 if Ekind
(Pack
) = E_Package
7866 and then Is_Generic_Instance
(Pack
)
7867 and then Nkind
(Parent
(Unit_Declaration_Node
(Pack
))) =
7873 Pack
:= Scope
(Pack
);
7877 end Within_Compilation_Unit_Instance
;
7879 -- Local declarations
7881 Context
: constant Node_Id
:= Parent
(Subp_Body
);
7882 Loc
: constant Source_Ptr
:= Sloc
(Subp_Body
);
7883 Subp_Id
: constant Entity_Id
:= Unique_Defining_Entity
(Subp_Body
);
7884 Subp_Decl
: constant Node_Id
:= Unit_Declaration_Node
(Subp_Id
);
7887 Flag_Id
: Entity_Id
;
7890 Tag_Typ
: Entity_Id
;
7892 -- Start of processing for Install_Primitive_Elaboration_Check
7895 -- Do not generate an elaboration check in compilation modes where
7896 -- expansion is not desirable.
7898 if ASIS_Mode
or GNATprove_Mode
then
7901 -- Do not generate an elaboration check if all checks have been
7904 elsif Suppress_Checks
then
7907 -- Do not generate an elaboration check if the related subprogram is
7908 -- not subjected to accessibility checks.
7910 elsif Elaboration_Checks_Suppressed
(Subp_Id
) then
7913 -- Do not generate an elaboration check if such code is not desirable
7915 elsif Restriction_Active
(No_Elaboration_Code
) then
7918 -- Do not consider subprograms which act as compilation units, because
7919 -- they cannot be the target of a dispatching call.
7921 elsif Nkind
(Context
) = N_Compilation_Unit
then
7924 -- Do not consider anything other than nonabstract library-level source
7928 (Comes_From_Source
(Subp_Id
)
7929 and then Is_Library_Level_Entity
(Subp_Id
)
7930 and then Is_Primitive
(Subp_Id
)
7931 and then not Is_Abstract_Subprogram
(Subp_Id
))
7935 -- Do not consider inlined primitives, because once the body is inlined
7936 -- the reference to the elaboration flag will be out of place and will
7937 -- result in an undefined symbol.
7939 elsif Is_Inlined
(Subp_Id
) or else Has_Pragma_Inline
(Subp_Id
) then
7942 -- Do not generate a duplicate elaboration check. This happens only in
7943 -- the case of primitives completed by an expression function, as the
7944 -- corresponding body is apparently analyzed and expanded twice.
7946 elsif Analyzed
(Subp_Body
) then
7949 -- Do not consider primitives which occur within an instance that acts
7950 -- as a compilation unit. Such an instance defines its spec and body out
7951 -- of order (body is first) within the tree, which causes the reference
7952 -- to the elaboration flag to appear as an undefined symbol.
7954 elsif Within_Compilation_Unit_Instance
(Subp_Id
) then
7958 Tag_Typ
:= Find_Dispatching_Type
(Subp_Id
);
7960 -- Only tagged primitives may be the target of a dispatching call
7962 if No
(Tag_Typ
) then
7965 -- Do not consider finalization-related primitives, because they may
7966 -- need to be called while elaboration is taking place.
7968 elsif Is_Controlled
(Tag_Typ
)
7969 and then Nam_In
(Chars
(Subp_Id
), Name_Adjust
,
7976 -- Create the declaration of the elaboration flag. The name carries a
7977 -- unique counter in case of name overloading.
7980 Make_Defining_Identifier
(Loc
,
7981 Chars
=> New_External_Name
(Chars
(Subp_Id
), 'E', -1));
7982 Set_Is_Frozen
(Flag_Id
);
7984 -- Insert the declaration of the elaboration flag in front of the
7985 -- primitive spec and analyze it in the proper context.
7987 Push_Scope
(Scope
(Subp_Id
));
7990 -- E : Boolean := False;
7992 Insert_Action
(Subp_Decl
,
7993 Make_Object_Declaration
(Loc
,
7994 Defining_Identifier
=> Flag_Id
,
7995 Object_Definition
=> New_Occurrence_Of
(Standard_Boolean
, Loc
),
7996 Expression
=> New_Occurrence_Of
(Standard_False
, Loc
)));
7999 -- Prevent the compiler from optimizing the elaboration check by killing
8000 -- the current value of the flag and the associated assignment.
8002 Set_Current_Value
(Flag_Id
, Empty
);
8003 Set_Last_Assignment
(Flag_Id
, Empty
);
8005 -- Add a check at the top of the body declarations to ensure that the
8006 -- elaboration flag has been set.
8008 Decls
:= Declarations
(Subp_Body
);
8012 Set_Declarations
(Subp_Body
, Decls
);
8017 -- raise Program_Error with "access before elaboration";
8021 Make_Raise_Program_Error
(Loc
,
8024 Right_Opnd
=> New_Occurrence_Of
(Flag_Id
, Loc
)),
8025 Reason
=> PE_Access_Before_Elaboration
));
8027 Analyze
(First
(Decls
));
8029 -- Set the elaboration flag once the body has been elaborated. Insert
8030 -- the statement after the subprogram stub when the primitive body is
8033 if Nkind
(Context
) = N_Subunit
then
8034 Set_Ins
:= Corresponding_Stub
(Context
);
8036 Set_Ins
:= Subp_Body
;
8043 Make_Assignment_Statement
(Loc
,
8044 Name
=> New_Occurrence_Of
(Flag_Id
, Loc
),
8045 Expression
=> New_Occurrence_Of
(Standard_True
, Loc
));
8047 -- Mark the assignment statement as elaboration code. This allows the
8048 -- early call region mechanism (see Sem_Elab) to properly ignore such
8049 -- assignments even though they are non-preelaborable code.
8051 Set_Is_Elaboration_Code
(Set_Stmt
);
8053 Insert_After_And_Analyze
(Set_Ins
, Set_Stmt
);
8054 end Install_Primitive_Elaboration_Check
;
8056 --------------------------
8057 -- Install_Static_Check --
8058 --------------------------
8060 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
) is
8061 Stat
: constant Boolean := Is_OK_Static_Expression
(R_Cno
);
8062 Typ
: constant Entity_Id
:= Etype
(R_Cno
);
8066 Make_Raise_Constraint_Error
(Loc
,
8067 Reason
=> CE_Range_Check_Failed
));
8068 Set_Analyzed
(R_Cno
);
8069 Set_Etype
(R_Cno
, Typ
);
8070 Set_Raises_Constraint_Error
(R_Cno
);
8071 Set_Is_Static_Expression
(R_Cno
, Stat
);
8073 -- Now deal with possible local raise handling
8075 Possible_Local_Raise
(R_Cno
, Standard_Constraint_Error
);
8076 end Install_Static_Check
;
8078 -------------------------
8079 -- Is_Check_Suppressed --
8080 -------------------------
8082 function Is_Check_Suppressed
(E
: Entity_Id
; C
: Check_Id
) return Boolean is
8083 Ptr
: Suppress_Stack_Entry_Ptr
;
8086 -- First search the local entity suppress stack. We search this from the
8087 -- top of the stack down so that we get the innermost entry that applies
8088 -- to this case if there are nested entries.
8090 Ptr
:= Local_Suppress_Stack_Top
;
8091 while Ptr
/= null loop
8092 if (Ptr
.Entity
= Empty
or else Ptr
.Entity
= E
)
8093 and then (Ptr
.Check
= All_Checks
or else Ptr
.Check
= C
)
8095 return Ptr
.Suppress
;
8101 -- Now search the global entity suppress table for a matching entry.
8102 -- We also search this from the top down so that if there are multiple
8103 -- pragmas for the same entity, the last one applies (not clear what
8104 -- or whether the RM specifies this handling, but it seems reasonable).
8106 Ptr
:= Global_Suppress_Stack_Top
;
8107 while Ptr
/= null loop
8108 if (Ptr
.Entity
= Empty
or else Ptr
.Entity
= E
)
8109 and then (Ptr
.Check
= All_Checks
or else Ptr
.Check
= C
)
8111 return Ptr
.Suppress
;
8117 -- If we did not find a matching entry, then use the normal scope
8118 -- suppress value after all (actually this will be the global setting
8119 -- since it clearly was not overridden at any point). For a predefined
8120 -- check, we test the specific flag. For a user defined check, we check
8121 -- the All_Checks flag. The Overflow flag requires special handling to
8122 -- deal with the General vs Assertion case.
8124 if C
= Overflow_Check
then
8125 return Overflow_Checks_Suppressed
(Empty
);
8127 elsif C
in Predefined_Check_Id
then
8128 return Scope_Suppress
.Suppress
(C
);
8131 return Scope_Suppress
.Suppress
(All_Checks
);
8133 end Is_Check_Suppressed
;
8135 ---------------------
8136 -- Kill_All_Checks --
8137 ---------------------
8139 procedure Kill_All_Checks
is
8141 if Debug_Flag_CC
then
8142 w
("Kill_All_Checks");
8145 -- We reset the number of saved checks to zero, and also modify all
8146 -- stack entries for statement ranges to indicate that the number of
8147 -- checks at each level is now zero.
8149 Num_Saved_Checks
:= 0;
8151 -- Note: the Int'Min here avoids any possibility of J being out of
8152 -- range when called from e.g. Conditional_Statements_Begin.
8154 for J
in 1 .. Int
'Min (Saved_Checks_TOS
, Saved_Checks_Stack
'Last) loop
8155 Saved_Checks_Stack
(J
) := 0;
8157 end Kill_All_Checks
;
8163 procedure Kill_Checks
(V
: Entity_Id
) is
8165 if Debug_Flag_CC
then
8166 w
("Kill_Checks for entity", Int
(V
));
8169 for J
in 1 .. Num_Saved_Checks
loop
8170 if Saved_Checks
(J
).Entity
= V
then
8171 if Debug_Flag_CC
then
8172 w
(" Checks killed for saved check ", J
);
8175 Saved_Checks
(J
).Killed
:= True;
8180 ------------------------------
8181 -- Length_Checks_Suppressed --
8182 ------------------------------
8184 function Length_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
8186 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
8187 return Is_Check_Suppressed
(E
, Length_Check
);
8189 return Scope_Suppress
.Suppress
(Length_Check
);
8191 end Length_Checks_Suppressed
;
8193 -----------------------
8194 -- Make_Bignum_Block --
8195 -----------------------
8197 function Make_Bignum_Block
(Loc
: Source_Ptr
) return Node_Id
is
8198 M
: constant Entity_Id
:= Make_Defining_Identifier
(Loc
, Name_uM
);
8201 Make_Block_Statement
(Loc
,
8203 New_List
(Build_SS_Mark_Call
(Loc
, M
)),
8204 Handled_Statement_Sequence
=>
8205 Make_Handled_Sequence_Of_Statements
(Loc
,
8206 Statements
=> New_List
(Build_SS_Release_Call
(Loc
, M
))));
8207 end Make_Bignum_Block
;
8209 ----------------------------------
8210 -- Minimize_Eliminate_Overflows --
8211 ----------------------------------
8213 -- This is a recursive routine that is called at the top of an expression
8214 -- tree to properly process overflow checking for a whole subtree by making
8215 -- recursive calls to process operands. This processing may involve the use
8216 -- of bignum or long long integer arithmetic, which will change the types
8217 -- of operands and results. That's why we can't do this bottom up (since
8218 -- it would interfere with semantic analysis).
8220 -- What happens is that if MINIMIZED/ELIMINATED mode is in effect then
8221 -- the operator expansion routines, as well as the expansion routines for
8222 -- if/case expression, do nothing (for the moment) except call the routine
8223 -- to apply the overflow check (Apply_Arithmetic_Overflow_Check). That
8224 -- routine does nothing for non top-level nodes, so at the point where the
8225 -- call is made for the top level node, the entire expression subtree has
8226 -- not been expanded, or processed for overflow. All that has to happen as
8227 -- a result of the top level call to this routine.
8229 -- As noted above, the overflow processing works by making recursive calls
8230 -- for the operands, and figuring out what to do, based on the processing
8231 -- of these operands (e.g. if a bignum operand appears, the parent op has
8232 -- to be done in bignum mode), and the determined ranges of the operands.
8234 -- After possible rewriting of a constituent subexpression node, a call is
8235 -- made to either reexpand the node (if nothing has changed) or reanalyze
8236 -- the node (if it has been modified by the overflow check processing). The
8237 -- Analyzed_Flag is set to False before the reexpand/reanalyze. To avoid
8238 -- a recursive call into the whole overflow apparatus, an important rule
8239 -- for this call is that the overflow handling mode must be temporarily set
8242 procedure Minimize_Eliminate_Overflows
8246 Top_Level
: Boolean)
8248 Rtyp
: constant Entity_Id
:= Etype
(N
);
8249 pragma Assert
(Is_Signed_Integer_Type
(Rtyp
));
8250 -- Result type, must be a signed integer type
8252 Check_Mode
: constant Overflow_Mode_Type
:= Overflow_Check_Mode
;
8253 pragma Assert
(Check_Mode
in Minimized_Or_Eliminated
);
8255 Loc
: constant Source_Ptr
:= Sloc
(N
);
8258 -- Ranges of values for right operand (operator case)
8260 Llo
: Uint
:= No_Uint
; -- initialize to prevent warning
8261 Lhi
: Uint
:= No_Uint
; -- initialize to prevent warning
8262 -- Ranges of values for left operand (operator case)
8264 LLIB
: constant Entity_Id
:= Base_Type
(Standard_Long_Long_Integer
);
8265 -- Operands and results are of this type when we convert
8267 LLLo
: constant Uint
:= Intval
(Type_Low_Bound
(LLIB
));
8268 LLHi
: constant Uint
:= Intval
(Type_High_Bound
(LLIB
));
8269 -- Bounds of Long_Long_Integer
8271 Binary
: constant Boolean := Nkind
(N
) in N_Binary_Op
;
8272 -- Indicates binary operator case
8275 -- Used in call to Determine_Range
8277 Bignum_Operands
: Boolean;
8278 -- Set True if one or more operands is already of type Bignum, meaning
8279 -- that for sure (regardless of Top_Level setting) we are committed to
8280 -- doing the operation in Bignum mode (or in the case of a case or if
8281 -- expression, converting all the dependent expressions to Bignum).
8283 Long_Long_Integer_Operands
: Boolean;
8284 -- Set True if one or more operands is already of type Long_Long_Integer
8285 -- which means that if the result is known to be in the result type
8286 -- range, then we must convert such operands back to the result type.
8288 procedure Reanalyze
(Typ
: Entity_Id
; Suppress
: Boolean := False);
8289 -- This is called when we have modified the node and we therefore need
8290 -- to reanalyze it. It is important that we reset the mode to STRICT for
8291 -- this reanalysis, since if we leave it in MINIMIZED or ELIMINATED mode
8292 -- we would reenter this routine recursively which would not be good.
8293 -- The argument Suppress is set True if we also want to suppress
8294 -- overflow checking for the reexpansion (this is set when we know
8295 -- overflow is not possible). Typ is the type for the reanalysis.
8297 procedure Reexpand
(Suppress
: Boolean := False);
8298 -- This is like Reanalyze, but does not do the Analyze step, it only
8299 -- does a reexpansion. We do this reexpansion in STRICT mode, so that
8300 -- instead of reentering the MINIMIZED/ELIMINATED mode processing, we
8301 -- follow the normal expansion path (e.g. converting A**4 to A**2**2).
8302 -- Note that skipping reanalysis is not just an optimization, testing
8303 -- has showed up several complex cases in which reanalyzing an already
8304 -- analyzed node causes incorrect behavior.
8306 function In_Result_Range
return Boolean;
8307 -- Returns True iff Lo .. Hi are within range of the result type
8309 procedure Max
(A
: in out Uint
; B
: Uint
);
8310 -- If A is No_Uint, sets A to B, else to UI_Max (A, B)
8312 procedure Min
(A
: in out Uint
; B
: Uint
);
8313 -- If A is No_Uint, sets A to B, else to UI_Min (A, B)
8315 ---------------------
8316 -- In_Result_Range --
8317 ---------------------
8319 function In_Result_Range
return Boolean is
8321 if Lo
= No_Uint
or else Hi
= No_Uint
then
8324 elsif Is_OK_Static_Subtype
(Etype
(N
)) then
8325 return Lo
>= Expr_Value
(Type_Low_Bound
(Rtyp
))
8327 Hi
<= Expr_Value
(Type_High_Bound
(Rtyp
));
8330 return Lo
>= Expr_Value
(Type_Low_Bound
(Base_Type
(Rtyp
)))
8332 Hi
<= Expr_Value
(Type_High_Bound
(Base_Type
(Rtyp
)));
8334 end In_Result_Range
;
8340 procedure Max
(A
: in out Uint
; B
: Uint
) is
8342 if A
= No_Uint
or else B
> A
then
8351 procedure Min
(A
: in out Uint
; B
: Uint
) is
8353 if A
= No_Uint
or else B
< A
then
8362 procedure Reanalyze
(Typ
: Entity_Id
; Suppress
: Boolean := False) is
8363 Svg
: constant Overflow_Mode_Type
:=
8364 Scope_Suppress
.Overflow_Mode_General
;
8365 Sva
: constant Overflow_Mode_Type
:=
8366 Scope_Suppress
.Overflow_Mode_Assertions
;
8367 Svo
: constant Boolean :=
8368 Scope_Suppress
.Suppress
(Overflow_Check
);
8371 Scope_Suppress
.Overflow_Mode_General
:= Strict
;
8372 Scope_Suppress
.Overflow_Mode_Assertions
:= Strict
;
8375 Scope_Suppress
.Suppress
(Overflow_Check
) := True;
8378 Analyze_And_Resolve
(N
, Typ
);
8380 Scope_Suppress
.Suppress
(Overflow_Check
) := Svo
;
8381 Scope_Suppress
.Overflow_Mode_General
:= Svg
;
8382 Scope_Suppress
.Overflow_Mode_Assertions
:= Sva
;
8389 procedure Reexpand
(Suppress
: Boolean := False) is
8390 Svg
: constant Overflow_Mode_Type
:=
8391 Scope_Suppress
.Overflow_Mode_General
;
8392 Sva
: constant Overflow_Mode_Type
:=
8393 Scope_Suppress
.Overflow_Mode_Assertions
;
8394 Svo
: constant Boolean :=
8395 Scope_Suppress
.Suppress
(Overflow_Check
);
8398 Scope_Suppress
.Overflow_Mode_General
:= Strict
;
8399 Scope_Suppress
.Overflow_Mode_Assertions
:= Strict
;
8400 Set_Analyzed
(N
, False);
8403 Scope_Suppress
.Suppress
(Overflow_Check
) := True;
8408 Scope_Suppress
.Suppress
(Overflow_Check
) := Svo
;
8409 Scope_Suppress
.Overflow_Mode_General
:= Svg
;
8410 Scope_Suppress
.Overflow_Mode_Assertions
:= Sva
;
8413 -- Start of processing for Minimize_Eliminate_Overflows
8416 -- Default initialize Lo and Hi since these are not guaranteed to be
8422 -- Case where we do not have a signed integer arithmetic operation
8424 if not Is_Signed_Integer_Arithmetic_Op
(N
) then
8426 -- Use the normal Determine_Range routine to get the range. We
8427 -- don't require operands to be valid, invalid values may result in
8428 -- rubbish results where the result has not been properly checked for
8429 -- overflow, that's fine.
8431 Determine_Range
(N
, OK
, Lo
, Hi
, Assume_Valid
=> False);
8433 -- If Determine_Range did not work (can this in fact happen? Not
8434 -- clear but might as well protect), use type bounds.
8437 Lo
:= Intval
(Type_Low_Bound
(Base_Type
(Etype
(N
))));
8438 Hi
:= Intval
(Type_High_Bound
(Base_Type
(Etype
(N
))));
8441 -- If we don't have a binary operator, all we have to do is to set
8442 -- the Hi/Lo range, so we are done.
8446 -- Processing for if expression
8448 elsif Nkind
(N
) = N_If_Expression
then
8450 Then_DE
: constant Node_Id
:= Next
(First
(Expressions
(N
)));
8451 Else_DE
: constant Node_Id
:= Next
(Then_DE
);
8454 Bignum_Operands
:= False;
8456 Minimize_Eliminate_Overflows
8457 (Then_DE
, Lo
, Hi
, Top_Level
=> False);
8459 if Lo
= No_Uint
then
8460 Bignum_Operands
:= True;
8463 Minimize_Eliminate_Overflows
8464 (Else_DE
, Rlo
, Rhi
, Top_Level
=> False);
8466 if Rlo
= No_Uint
then
8467 Bignum_Operands
:= True;
8469 Long_Long_Integer_Operands
:=
8470 Etype
(Then_DE
) = LLIB
or else Etype
(Else_DE
) = LLIB
;
8476 -- If at least one of our operands is now Bignum, we must rebuild
8477 -- the if expression to use Bignum operands. We will analyze the
8478 -- rebuilt if expression with overflow checks off, since once we
8479 -- are in bignum mode, we are all done with overflow checks.
8481 if Bignum_Operands
then
8483 Make_If_Expression
(Loc
,
8484 Expressions
=> New_List
(
8485 Remove_Head
(Expressions
(N
)),
8486 Convert_To_Bignum
(Then_DE
),
8487 Convert_To_Bignum
(Else_DE
)),
8488 Is_Elsif
=> Is_Elsif
(N
)));
8490 Reanalyze
(RTE
(RE_Bignum
), Suppress
=> True);
8492 -- If we have no Long_Long_Integer operands, then we are in result
8493 -- range, since it means that none of our operands felt the need
8494 -- to worry about overflow (otherwise it would have already been
8495 -- converted to long long integer or bignum). We reexpand to
8496 -- complete the expansion of the if expression (but we do not
8497 -- need to reanalyze).
8499 elsif not Long_Long_Integer_Operands
then
8500 Set_Do_Overflow_Check
(N
, False);
8503 -- Otherwise convert us to long long integer mode. Note that we
8504 -- don't need any further overflow checking at this level.
8507 Convert_To_And_Rewrite
(LLIB
, Then_DE
);
8508 Convert_To_And_Rewrite
(LLIB
, Else_DE
);
8509 Set_Etype
(N
, LLIB
);
8511 -- Now reanalyze with overflow checks off
8513 Set_Do_Overflow_Check
(N
, False);
8514 Reanalyze
(LLIB
, Suppress
=> True);
8520 -- Here for case expression
8522 elsif Nkind
(N
) = N_Case_Expression
then
8523 Bignum_Operands
:= False;
8524 Long_Long_Integer_Operands
:= False;
8530 -- Loop through expressions applying recursive call
8532 Alt
:= First
(Alternatives
(N
));
8533 while Present
(Alt
) loop
8535 Aexp
: constant Node_Id
:= Expression
(Alt
);
8538 Minimize_Eliminate_Overflows
8539 (Aexp
, Lo
, Hi
, Top_Level
=> False);
8541 if Lo
= No_Uint
then
8542 Bignum_Operands
:= True;
8543 elsif Etype
(Aexp
) = LLIB
then
8544 Long_Long_Integer_Operands
:= True;
8551 -- If we have no bignum or long long integer operands, it means
8552 -- that none of our dependent expressions could raise overflow.
8553 -- In this case, we simply return with no changes except for
8554 -- resetting the overflow flag, since we are done with overflow
8555 -- checks for this node. We will reexpand to get the needed
8556 -- expansion for the case expression, but we do not need to
8557 -- reanalyze, since nothing has changed.
8559 if not (Bignum_Operands
or Long_Long_Integer_Operands
) then
8560 Set_Do_Overflow_Check
(N
, False);
8561 Reexpand
(Suppress
=> True);
8563 -- Otherwise we are going to rebuild the case expression using
8564 -- either bignum or long long integer operands throughout.
8569 pragma Warnings
(Off
, Rtype
);
8574 New_Alts
:= New_List
;
8575 Alt
:= First
(Alternatives
(N
));
8576 while Present
(Alt
) loop
8577 if Bignum_Operands
then
8578 New_Exp
:= Convert_To_Bignum
(Expression
(Alt
));
8579 Rtype
:= RTE
(RE_Bignum
);
8581 New_Exp
:= Convert_To
(LLIB
, Expression
(Alt
));
8585 Append_To
(New_Alts
,
8586 Make_Case_Expression_Alternative
(Sloc
(Alt
),
8588 Discrete_Choices
=> Discrete_Choices
(Alt
),
8589 Expression
=> New_Exp
));
8595 Make_Case_Expression
(Loc
,
8596 Expression
=> Expression
(N
),
8597 Alternatives
=> New_Alts
));
8599 Reanalyze
(Rtype
, Suppress
=> True);
8607 -- If we have an arithmetic operator we make recursive calls on the
8608 -- operands to get the ranges (and to properly process the subtree
8609 -- that lies below us).
8611 Minimize_Eliminate_Overflows
8612 (Right_Opnd
(N
), Rlo
, Rhi
, Top_Level
=> False);
8615 Minimize_Eliminate_Overflows
8616 (Left_Opnd
(N
), Llo
, Lhi
, Top_Level
=> False);
8619 -- Record if we have Long_Long_Integer operands
8621 Long_Long_Integer_Operands
:=
8622 Etype
(Right_Opnd
(N
)) = LLIB
8623 or else (Binary
and then Etype
(Left_Opnd
(N
)) = LLIB
);
8625 -- If either operand is a bignum, then result will be a bignum and we
8626 -- don't need to do any range analysis. As previously discussed we could
8627 -- do range analysis in such cases, but it could mean working with giant
8628 -- numbers at compile time for very little gain (the number of cases
8629 -- in which we could slip back from bignum mode is small).
8631 if Rlo
= No_Uint
or else (Binary
and then Llo
= No_Uint
) then
8634 Bignum_Operands
:= True;
8636 -- Otherwise compute result range
8639 Bignum_Operands
:= False;
8647 Hi
:= UI_Max
(abs Rlo
, abs Rhi
);
8659 -- If the right operand can only be zero, set 0..0
8661 if Rlo
= 0 and then Rhi
= 0 then
8665 -- Possible bounds of division must come from dividing end
8666 -- values of the input ranges (four possibilities), provided
8667 -- zero is not included in the possible values of the right
8670 -- Otherwise, we just consider two intervals of values for
8671 -- the right operand: the interval of negative values (up to
8672 -- -1) and the interval of positive values (starting at 1).
8673 -- Since division by 1 is the identity, and division by -1
8674 -- is negation, we get all possible bounds of division in that
8675 -- case by considering:
8676 -- - all values from the division of end values of input
8678 -- - the end values of the left operand;
8679 -- - the negation of the end values of the left operand.
8683 Mrk
: constant Uintp
.Save_Mark
:= Mark
;
8684 -- Mark so we can release the RR and Ev values
8692 -- Discard extreme values of zero for the divisor, since
8693 -- they will simply result in an exception in any case.
8701 -- Compute possible bounds coming from dividing end
8702 -- values of the input ranges.
8709 Lo
:= UI_Min
(UI_Min
(Ev1
, Ev2
), UI_Min
(Ev3
, Ev4
));
8710 Hi
:= UI_Max
(UI_Max
(Ev1
, Ev2
), UI_Max
(Ev3
, Ev4
));
8712 -- If the right operand can be both negative or positive,
8713 -- include the end values of the left operand in the
8714 -- extreme values, as well as their negation.
8716 if Rlo
< 0 and then Rhi
> 0 then
8723 UI_Min
(UI_Min
(Ev1
, Ev2
), UI_Min
(Ev3
, Ev4
)));
8725 UI_Max
(UI_Max
(Ev1
, Ev2
), UI_Max
(Ev3
, Ev4
)));
8728 -- Release the RR and Ev values
8730 Release_And_Save
(Mrk
, Lo
, Hi
);
8738 -- Discard negative values for the exponent, since they will
8739 -- simply result in an exception in any case.
8747 -- Estimate number of bits in result before we go computing
8748 -- giant useless bounds. Basically the number of bits in the
8749 -- result is the number of bits in the base multiplied by the
8750 -- value of the exponent. If this is big enough that the result
8751 -- definitely won't fit in Long_Long_Integer, switch to bignum
8752 -- mode immediately, and avoid computing giant bounds.
8754 -- The comparison here is approximate, but conservative, it
8755 -- only clicks on cases that are sure to exceed the bounds.
8757 if Num_Bits
(UI_Max
(abs Llo
, abs Lhi
)) * Rhi
+ 1 > 100 then
8761 -- If right operand is zero then result is 1
8768 -- High bound comes either from exponentiation of largest
8769 -- positive value to largest exponent value, or from
8770 -- the exponentiation of most negative value to an
8784 if Rhi
mod 2 = 0 then
8787 Hi2
:= Llo
** (Rhi
- 1);
8793 Hi
:= UI_Max
(Hi1
, Hi2
);
8796 -- Result can only be negative if base can be negative
8799 if Rhi
mod 2 = 0 then
8800 Lo
:= Llo
** (Rhi
- 1);
8805 -- Otherwise low bound is minimum ** minimum
8822 Maxabs
: constant Uint
:= UI_Max
(abs Rlo
, abs Rhi
) - 1;
8823 -- This is the maximum absolute value of the result
8829 -- The result depends only on the sign and magnitude of
8830 -- the right operand, it does not depend on the sign or
8831 -- magnitude of the left operand.
8844 when N_Op_Multiply
=>
8846 -- Possible bounds of multiplication must come from multiplying
8847 -- end values of the input ranges (four possibilities).
8850 Mrk
: constant Uintp
.Save_Mark
:= Mark
;
8851 -- Mark so we can release the Ev values
8853 Ev1
: constant Uint
:= Llo
* Rlo
;
8854 Ev2
: constant Uint
:= Llo
* Rhi
;
8855 Ev3
: constant Uint
:= Lhi
* Rlo
;
8856 Ev4
: constant Uint
:= Lhi
* Rhi
;
8859 Lo
:= UI_Min
(UI_Min
(Ev1
, Ev2
), UI_Min
(Ev3
, Ev4
));
8860 Hi
:= UI_Max
(UI_Max
(Ev1
, Ev2
), UI_Max
(Ev3
, Ev4
));
8862 -- Release the Ev values
8864 Release_And_Save
(Mrk
, Lo
, Hi
);
8867 -- Plus operator (affirmation)
8877 Maxabs
: constant Uint
:= UI_Max
(abs Rlo
, abs Rhi
) - 1;
8878 -- This is the maximum absolute value of the result. Note
8879 -- that the result range does not depend on the sign of the
8886 -- Case of left operand negative, which results in a range
8887 -- of -Maxabs .. 0 for those negative values. If there are
8888 -- no negative values then Lo value of result is always 0.
8894 -- Case of left operand positive
8903 when N_Op_Subtract
=>
8907 -- Nothing else should be possible
8910 raise Program_Error
;
8914 -- Here for the case where we have not rewritten anything (no bignum
8915 -- operands or long long integer operands), and we know the result.
8916 -- If we know we are in the result range, and we do not have Bignum
8917 -- operands or Long_Long_Integer operands, we can just reexpand with
8918 -- overflow checks turned off (since we know we cannot have overflow).
8919 -- As always the reexpansion is required to complete expansion of the
8920 -- operator, but we do not need to reanalyze, and we prevent recursion
8921 -- by suppressing the check.
8923 if not (Bignum_Operands
or Long_Long_Integer_Operands
)
8924 and then In_Result_Range
8926 Set_Do_Overflow_Check
(N
, False);
8927 Reexpand
(Suppress
=> True);
8930 -- Here we know that we are not in the result range, and in the general
8931 -- case we will move into either the Bignum or Long_Long_Integer domain
8932 -- to compute the result. However, there is one exception. If we are
8933 -- at the top level, and we do not have Bignum or Long_Long_Integer
8934 -- operands, we will have to immediately convert the result back to
8935 -- the result type, so there is no point in Bignum/Long_Long_Integer
8939 and then not (Bignum_Operands
or Long_Long_Integer_Operands
)
8941 -- One further refinement. If we are at the top level, but our parent
8942 -- is a type conversion, then go into bignum or long long integer node
8943 -- since the result will be converted to that type directly without
8944 -- going through the result type, and we may avoid an overflow. This
8945 -- is the case for example of Long_Long_Integer (A ** 4), where A is
8946 -- of type Integer, and the result A ** 4 fits in Long_Long_Integer
8947 -- but does not fit in Integer.
8949 and then Nkind
(Parent
(N
)) /= N_Type_Conversion
8951 -- Here keep original types, but we need to complete analysis
8953 -- One subtlety. We can't just go ahead and do an analyze operation
8954 -- here because it will cause recursion into the whole MINIMIZED/
8955 -- ELIMINATED overflow processing which is not what we want. Here
8956 -- we are at the top level, and we need a check against the result
8957 -- mode (i.e. we want to use STRICT mode). So do exactly that.
8958 -- Also, we have not modified the node, so this is a case where
8959 -- we need to reexpand, but not reanalyze.
8964 -- Cases where we do the operation in Bignum mode. This happens either
8965 -- because one of our operands is in Bignum mode already, or because
8966 -- the computed bounds are outside the bounds of Long_Long_Integer,
8967 -- which in some cases can be indicated by Hi and Lo being No_Uint.
8969 -- Note: we could do better here and in some cases switch back from
8970 -- Bignum mode to normal mode, e.g. big mod 2 must be in the range
8971 -- 0 .. 1, but the cases are rare and it is not worth the effort.
8972 -- Failing to do this switching back is only an efficiency issue.
8974 elsif Lo
= No_Uint
or else Lo
< LLLo
or else Hi
> LLHi
then
8976 -- OK, we are definitely outside the range of Long_Long_Integer. The
8977 -- question is whether to move to Bignum mode, or stay in the domain
8978 -- of Long_Long_Integer, signalling that an overflow check is needed.
8980 -- Obviously in MINIMIZED mode we stay with LLI, since we are not in
8981 -- the Bignum business. In ELIMINATED mode, we will normally move
8982 -- into Bignum mode, but there is an exception if neither of our
8983 -- operands is Bignum now, and we are at the top level (Top_Level
8984 -- set True). In this case, there is no point in moving into Bignum
8985 -- mode to prevent overflow if the caller will immediately convert
8986 -- the Bignum value back to LLI with an overflow check. It's more
8987 -- efficient to stay in LLI mode with an overflow check (if needed)
8989 if Check_Mode
= Minimized
8990 or else (Top_Level
and not Bignum_Operands
)
8992 if Do_Overflow_Check
(N
) then
8993 Enable_Overflow_Check
(N
);
8996 -- The result now has to be in Long_Long_Integer mode, so adjust
8997 -- the possible range to reflect this. Note these calls also
8998 -- change No_Uint values from the top level case to LLI bounds.
9003 -- Otherwise we are in ELIMINATED mode and we switch to Bignum mode
9006 pragma Assert
(Check_Mode
= Eliminated
);
9015 Fent
:= RTE
(RE_Big_Abs
);
9018 Fent
:= RTE
(RE_Big_Add
);
9021 Fent
:= RTE
(RE_Big_Div
);
9024 Fent
:= RTE
(RE_Big_Exp
);
9027 Fent
:= RTE
(RE_Big_Neg
);
9030 Fent
:= RTE
(RE_Big_Mod
);
9032 when N_Op_Multiply
=>
9033 Fent
:= RTE
(RE_Big_Mul
);
9036 Fent
:= RTE
(RE_Big_Rem
);
9038 when N_Op_Subtract
=>
9039 Fent
:= RTE
(RE_Big_Sub
);
9041 -- Anything else is an internal error, this includes the
9042 -- N_Op_Plus case, since how can plus cause the result
9043 -- to be out of range if the operand is in range?
9046 raise Program_Error
;
9049 -- Construct argument list for Bignum call, converting our
9050 -- operands to Bignum form if they are not already there.
9055 Append_To
(Args
, Convert_To_Bignum
(Left_Opnd
(N
)));
9058 Append_To
(Args
, Convert_To_Bignum
(Right_Opnd
(N
)));
9060 -- Now rewrite the arithmetic operator with a call to the
9061 -- corresponding bignum function.
9064 Make_Function_Call
(Loc
,
9065 Name
=> New_Occurrence_Of
(Fent
, Loc
),
9066 Parameter_Associations
=> Args
));
9067 Reanalyze
(RTE
(RE_Bignum
), Suppress
=> True);
9069 -- Indicate result is Bignum mode
9077 -- Otherwise we are in range of Long_Long_Integer, so no overflow
9078 -- check is required, at least not yet.
9081 Set_Do_Overflow_Check
(N
, False);
9084 -- Here we are not in Bignum territory, but we may have long long
9085 -- integer operands that need special handling. First a special check:
9086 -- If an exponentiation operator exponent is of type Long_Long_Integer,
9087 -- it means we converted it to prevent overflow, but exponentiation
9088 -- requires a Natural right operand, so convert it back to Natural.
9089 -- This conversion may raise an exception which is fine.
9091 if Nkind
(N
) = N_Op_Expon
and then Etype
(Right_Opnd
(N
)) = LLIB
then
9092 Convert_To_And_Rewrite
(Standard_Natural
, Right_Opnd
(N
));
9095 -- Here we will do the operation in Long_Long_Integer. We do this even
9096 -- if we know an overflow check is required, better to do this in long
9097 -- long integer mode, since we are less likely to overflow.
9099 -- Convert right or only operand to Long_Long_Integer, except that
9100 -- we do not touch the exponentiation right operand.
9102 if Nkind
(N
) /= N_Op_Expon
then
9103 Convert_To_And_Rewrite
(LLIB
, Right_Opnd
(N
));
9106 -- Convert left operand to Long_Long_Integer for binary case
9109 Convert_To_And_Rewrite
(LLIB
, Left_Opnd
(N
));
9112 -- Reset node to unanalyzed
9114 Set_Analyzed
(N
, False);
9115 Set_Etype
(N
, Empty
);
9116 Set_Entity
(N
, Empty
);
9118 -- Now analyze this new node. This reanalysis will complete processing
9119 -- for the node. In particular we will complete the expansion of an
9120 -- exponentiation operator (e.g. changing A ** 2 to A * A), and also
9121 -- we will complete any division checks (since we have not changed the
9122 -- setting of the Do_Division_Check flag).
9124 -- We do this reanalysis in STRICT mode to avoid recursion into the
9125 -- MINIMIZED/ELIMINATED handling, since we are now done with that.
9128 SG
: constant Overflow_Mode_Type
:=
9129 Scope_Suppress
.Overflow_Mode_General
;
9130 SA
: constant Overflow_Mode_Type
:=
9131 Scope_Suppress
.Overflow_Mode_Assertions
;
9134 Scope_Suppress
.Overflow_Mode_General
:= Strict
;
9135 Scope_Suppress
.Overflow_Mode_Assertions
:= Strict
;
9137 if not Do_Overflow_Check
(N
) then
9138 Reanalyze
(LLIB
, Suppress
=> True);
9143 Scope_Suppress
.Overflow_Mode_General
:= SG
;
9144 Scope_Suppress
.Overflow_Mode_Assertions
:= SA
;
9146 end Minimize_Eliminate_Overflows
;
9148 -------------------------
9149 -- Overflow_Check_Mode --
9150 -------------------------
9152 function Overflow_Check_Mode
return Overflow_Mode_Type
is
9154 if In_Assertion_Expr
= 0 then
9155 return Scope_Suppress
.Overflow_Mode_General
;
9157 return Scope_Suppress
.Overflow_Mode_Assertions
;
9159 end Overflow_Check_Mode
;
9161 --------------------------------
9162 -- Overflow_Checks_Suppressed --
9163 --------------------------------
9165 function Overflow_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
9167 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
9168 return Is_Check_Suppressed
(E
, Overflow_Check
);
9170 return Scope_Suppress
.Suppress
(Overflow_Check
);
9172 end Overflow_Checks_Suppressed
;
9174 ---------------------------------
9175 -- Predicate_Checks_Suppressed --
9176 ---------------------------------
9178 function Predicate_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
9180 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
9181 return Is_Check_Suppressed
(E
, Predicate_Check
);
9183 return Scope_Suppress
.Suppress
(Predicate_Check
);
9185 end Predicate_Checks_Suppressed
;
9187 -----------------------------
9188 -- Range_Checks_Suppressed --
9189 -----------------------------
9191 function Range_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
9194 if Kill_Range_Checks
(E
) then
9197 elsif Checks_May_Be_Suppressed
(E
) then
9198 return Is_Check_Suppressed
(E
, Range_Check
);
9202 return Scope_Suppress
.Suppress
(Range_Check
);
9203 end Range_Checks_Suppressed
;
9205 -----------------------------------------
9206 -- Range_Or_Validity_Checks_Suppressed --
9207 -----------------------------------------
9209 -- Note: the coding would be simpler here if we simply made appropriate
9210 -- calls to Range/Validity_Checks_Suppressed, but that would result in
9211 -- duplicated checks which we prefer to avoid.
9213 function Range_Or_Validity_Checks_Suppressed
9214 (Expr
: Node_Id
) return Boolean
9217 -- Immediate return if scope checks suppressed for either check
9219 if Scope_Suppress
.Suppress
(Range_Check
)
9221 Scope_Suppress
.Suppress
(Validity_Check
)
9226 -- If no expression, that's odd, decide that checks are suppressed,
9227 -- since we don't want anyone trying to do checks in this case, which
9228 -- is most likely the result of some other error.
9234 -- Expression is present, so perform suppress checks on type
9237 Typ
: constant Entity_Id
:= Etype
(Expr
);
9239 if Checks_May_Be_Suppressed
(Typ
)
9240 and then (Is_Check_Suppressed
(Typ
, Range_Check
)
9242 Is_Check_Suppressed
(Typ
, Validity_Check
))
9248 -- If expression is an entity name, perform checks on this entity
9250 if Is_Entity_Name
(Expr
) then
9252 Ent
: constant Entity_Id
:= Entity
(Expr
);
9254 if Checks_May_Be_Suppressed
(Ent
) then
9255 return Is_Check_Suppressed
(Ent
, Range_Check
)
9256 or else Is_Check_Suppressed
(Ent
, Validity_Check
);
9261 -- If we fall through, no checks suppressed
9264 end Range_Or_Validity_Checks_Suppressed
;
9270 procedure Remove_Checks
(Expr
: Node_Id
) is
9271 function Process
(N
: Node_Id
) return Traverse_Result
;
9272 -- Process a single node during the traversal
9274 procedure Traverse
is new Traverse_Proc
(Process
);
9275 -- The traversal procedure itself
9281 function Process
(N
: Node_Id
) return Traverse_Result
is
9283 if Nkind
(N
) not in N_Subexpr
then
9287 Set_Do_Range_Check
(N
, False);
9291 Traverse
(Left_Opnd
(N
));
9294 when N_Attribute_Reference
=>
9295 Set_Do_Overflow_Check
(N
, False);
9297 when N_Function_Call
=>
9298 Set_Do_Tag_Check
(N
, False);
9301 Set_Do_Overflow_Check
(N
, False);
9305 Set_Do_Division_Check
(N
, False);
9308 Set_Do_Length_Check
(N
, False);
9311 Set_Do_Division_Check
(N
, False);
9314 Set_Do_Length_Check
(N
, False);
9317 Set_Do_Division_Check
(N
, False);
9320 Set_Do_Length_Check
(N
, False);
9327 Traverse
(Left_Opnd
(N
));
9330 when N_Selected_Component
=>
9331 Set_Do_Discriminant_Check
(N
, False);
9333 when N_Type_Conversion
=>
9334 Set_Do_Length_Check
(N
, False);
9335 Set_Do_Tag_Check
(N
, False);
9336 Set_Do_Overflow_Check
(N
, False);
9345 -- Start of processing for Remove_Checks
9351 ----------------------------
9352 -- Selected_Length_Checks --
9353 ----------------------------
9355 function Selected_Length_Checks
9357 Target_Typ
: Entity_Id
;
9358 Source_Typ
: Entity_Id
;
9359 Warn_Node
: Node_Id
) return Check_Result
9361 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
9364 Expr_Actual
: Node_Id
;
9366 Cond
: Node_Id
:= Empty
;
9367 Do_Access
: Boolean := False;
9368 Wnode
: Node_Id
:= Warn_Node
;
9369 Ret_Result
: Check_Result
:= (Empty
, Empty
);
9370 Num_Checks
: Natural := 0;
9372 procedure Add_Check
(N
: Node_Id
);
9373 -- Adds the action given to Ret_Result if N is non-Empty
9375 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
;
9376 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
9377 -- Comments required ???
9379 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean;
9380 -- True for equal literals and for nodes that denote the same constant
9381 -- entity, even if its value is not a static constant. This includes the
9382 -- case of a discriminal reference within an init proc. Removes some
9383 -- obviously superfluous checks.
9385 function Length_E_Cond
9386 (Exptyp
: Entity_Id
;
9388 Indx
: Nat
) return Node_Id
;
9389 -- Returns expression to compute:
9390 -- Typ'Length /= Exptyp'Length
9392 function Length_N_Cond
9395 Indx
: Nat
) return Node_Id
;
9396 -- Returns expression to compute:
9397 -- Typ'Length /= Expr'Length
9403 procedure Add_Check
(N
: Node_Id
) is
9407 -- For now, ignore attempt to place more than two checks ???
9408 -- This is really worrisome, are we really discarding checks ???
9410 if Num_Checks
= 2 then
9414 pragma Assert
(Num_Checks
<= 1);
9415 Num_Checks
:= Num_Checks
+ 1;
9416 Ret_Result
(Num_Checks
) := N
;
9424 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
is
9425 SE
: constant Entity_Id
:= Scope
(E
);
9427 E1
: Entity_Id
:= E
;
9430 if Ekind
(Scope
(E
)) = E_Record_Type
9431 and then Has_Discriminants
(Scope
(E
))
9433 N
:= Build_Discriminal_Subtype_Of_Component
(E
);
9436 Insert_Action
(Ck_Node
, N
);
9437 E1
:= Defining_Identifier
(N
);
9441 if Ekind
(E1
) = E_String_Literal_Subtype
then
9443 Make_Integer_Literal
(Loc
,
9444 Intval
=> String_Literal_Length
(E1
));
9446 elsif SE
/= Standard_Standard
9447 and then Ekind
(Scope
(SE
)) = E_Protected_Type
9448 and then Has_Discriminants
(Scope
(SE
))
9449 and then Has_Completion
(Scope
(SE
))
9450 and then not Inside_Init_Proc
9452 -- If the type whose length is needed is a private component
9453 -- constrained by a discriminant, we must expand the 'Length
9454 -- attribute into an explicit computation, using the discriminal
9455 -- of the current protected operation. This is because the actual
9456 -- type of the prival is constructed after the protected opera-
9457 -- tion has been fully expanded.
9460 Indx_Type
: Node_Id
;
9463 Do_Expand
: Boolean := False;
9466 Indx_Type
:= First_Index
(E
);
9468 for J
in 1 .. Indx
- 1 loop
9469 Next_Index
(Indx_Type
);
9472 Get_Index_Bounds
(Indx_Type
, Lo
, Hi
);
9474 if Nkind
(Lo
) = N_Identifier
9475 and then Ekind
(Entity
(Lo
)) = E_In_Parameter
9477 Lo
:= Get_Discriminal
(E
, Lo
);
9481 if Nkind
(Hi
) = N_Identifier
9482 and then Ekind
(Entity
(Hi
)) = E_In_Parameter
9484 Hi
:= Get_Discriminal
(E
, Hi
);
9489 if not Is_Entity_Name
(Lo
) then
9490 Lo
:= Duplicate_Subexpr_No_Checks
(Lo
);
9493 if not Is_Entity_Name
(Hi
) then
9494 Lo
:= Duplicate_Subexpr_No_Checks
(Hi
);
9500 Make_Op_Subtract
(Loc
,
9504 Right_Opnd
=> Make_Integer_Literal
(Loc
, 1));
9509 Make_Attribute_Reference
(Loc
,
9510 Attribute_Name
=> Name_Length
,
9512 New_Occurrence_Of
(E1
, Loc
));
9515 Set_Expressions
(N
, New_List
(
9516 Make_Integer_Literal
(Loc
, Indx
)));
9525 Make_Attribute_Reference
(Loc
,
9526 Attribute_Name
=> Name_Length
,
9528 New_Occurrence_Of
(E1
, Loc
));
9531 Set_Expressions
(N
, New_List
(
9532 Make_Integer_Literal
(Loc
, Indx
)));
9543 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
9546 Make_Attribute_Reference
(Loc
,
9547 Attribute_Name
=> Name_Length
,
9549 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
9550 Expressions
=> New_List
(
9551 Make_Integer_Literal
(Loc
, Indx
)));
9558 function Length_E_Cond
9559 (Exptyp
: Entity_Id
;
9561 Indx
: Nat
) return Node_Id
9566 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
9567 Right_Opnd
=> Get_E_Length
(Exptyp
, Indx
));
9574 function Length_N_Cond
9577 Indx
: Nat
) return Node_Id
9582 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
9583 Right_Opnd
=> Get_N_Length
(Expr
, Indx
));
9590 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean is
9593 (Nkind
(L
) = N_Integer_Literal
9594 and then Nkind
(R
) = N_Integer_Literal
9595 and then Intval
(L
) = Intval
(R
))
9599 and then Ekind
(Entity
(L
)) = E_Constant
9600 and then ((Is_Entity_Name
(R
)
9601 and then Entity
(L
) = Entity
(R
))
9603 (Nkind
(R
) = N_Type_Conversion
9604 and then Is_Entity_Name
(Expression
(R
))
9605 and then Entity
(L
) = Entity
(Expression
(R
)))))
9609 and then Ekind
(Entity
(R
)) = E_Constant
9610 and then Nkind
(L
) = N_Type_Conversion
9611 and then Is_Entity_Name
(Expression
(L
))
9612 and then Entity
(R
) = Entity
(Expression
(L
)))
9616 and then Is_Entity_Name
(R
)
9617 and then Entity
(L
) = Entity
(R
)
9618 and then Ekind
(Entity
(L
)) = E_In_Parameter
9619 and then Inside_Init_Proc
);
9622 -- Start of processing for Selected_Length_Checks
9625 -- Checks will be applied only when generating code
9627 if not Expander_Active
then
9631 if Target_Typ
= Any_Type
9632 or else Target_Typ
= Any_Composite
9633 or else Raises_Constraint_Error
(Ck_Node
)
9642 T_Typ
:= Target_Typ
;
9644 if No
(Source_Typ
) then
9645 S_Typ
:= Etype
(Ck_Node
);
9647 S_Typ
:= Source_Typ
;
9650 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
9654 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
9655 S_Typ
:= Designated_Type
(S_Typ
);
9656 T_Typ
:= Designated_Type
(T_Typ
);
9659 -- A simple optimization for the null case
9661 if Known_Null
(Ck_Node
) then
9666 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
9667 if Is_Constrained
(T_Typ
) then
9669 -- The checking code to be generated will freeze the corresponding
9670 -- array type. However, we must freeze the type now, so that the
9671 -- freeze node does not appear within the generated if expression,
9674 Freeze_Before
(Ck_Node
, T_Typ
);
9676 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
9677 Exptyp
:= Get_Actual_Subtype
(Ck_Node
);
9679 if Is_Access_Type
(Exptyp
) then
9680 Exptyp
:= Designated_Type
(Exptyp
);
9683 -- String_Literal case. This needs to be handled specially be-
9684 -- cause no index types are available for string literals. The
9685 -- condition is simply:
9687 -- T_Typ'Length = string-literal-length
9689 if Nkind
(Expr_Actual
) = N_String_Literal
9690 and then Ekind
(Etype
(Expr_Actual
)) = E_String_Literal_Subtype
9694 Left_Opnd
=> Get_E_Length
(T_Typ
, 1),
9696 Make_Integer_Literal
(Loc
,
9698 String_Literal_Length
(Etype
(Expr_Actual
))));
9700 -- General array case. Here we have a usable actual subtype for
9701 -- the expression, and the condition is built from the two types
9704 -- T_Typ'Length /= Exptyp'Length or else
9705 -- T_Typ'Length (2) /= Exptyp'Length (2) or else
9706 -- T_Typ'Length (3) /= Exptyp'Length (3) or else
9709 elsif Is_Constrained
(Exptyp
) then
9711 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
9724 -- At the library level, we need to ensure that the type of
9725 -- the object is elaborated before the check itself is
9726 -- emitted. This is only done if the object is in the
9727 -- current compilation unit, otherwise the type is frozen
9728 -- and elaborated in its unit.
9730 if Is_Itype
(Exptyp
)
9732 Ekind
(Cunit_Entity
(Current_Sem_Unit
)) = E_Package
9734 not In_Package_Body
(Cunit_Entity
(Current_Sem_Unit
))
9735 and then In_Open_Scopes
(Scope
(Exptyp
))
9737 Ref_Node
:= Make_Itype_Reference
(Sloc
(Ck_Node
));
9738 Set_Itype
(Ref_Node
, Exptyp
);
9739 Insert_Action
(Ck_Node
, Ref_Node
);
9742 L_Index
:= First_Index
(T_Typ
);
9743 R_Index
:= First_Index
(Exptyp
);
9745 for Indx
in 1 .. Ndims
loop
9746 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
9748 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
9750 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
9751 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
9753 -- Deal with compile time length check. Note that we
9754 -- skip this in the access case, because the access
9755 -- value may be null, so we cannot know statically.
9758 and then Compile_Time_Known_Value
(L_Low
)
9759 and then Compile_Time_Known_Value
(L_High
)
9760 and then Compile_Time_Known_Value
(R_Low
)
9761 and then Compile_Time_Known_Value
(R_High
)
9763 if Expr_Value
(L_High
) >= Expr_Value
(L_Low
) then
9764 L_Length
:= Expr_Value
(L_High
) -
9765 Expr_Value
(L_Low
) + 1;
9767 L_Length
:= UI_From_Int
(0);
9770 if Expr_Value
(R_High
) >= Expr_Value
(R_Low
) then
9771 R_Length
:= Expr_Value
(R_High
) -
9772 Expr_Value
(R_Low
) + 1;
9774 R_Length
:= UI_From_Int
(0);
9777 if L_Length
> R_Length
then
9779 (Compile_Time_Constraint_Error
9780 (Wnode
, "too few elements for}??", T_Typ
));
9782 elsif L_Length
< R_Length
then
9784 (Compile_Time_Constraint_Error
9785 (Wnode
, "too many elements for}??", T_Typ
));
9788 -- The comparison for an individual index subtype
9789 -- is omitted if the corresponding index subtypes
9790 -- statically match, since the result is known to
9791 -- be true. Note that this test is worth while even
9792 -- though we do static evaluation, because non-static
9793 -- subtypes can statically match.
9796 Subtypes_Statically_Match
9797 (Etype
(L_Index
), Etype
(R_Index
))
9800 (Same_Bounds
(L_Low
, R_Low
)
9801 and then Same_Bounds
(L_High
, R_High
))
9804 (Cond
, Length_E_Cond
(Exptyp
, T_Typ
, Indx
));
9813 -- Handle cases where we do not get a usable actual subtype that
9814 -- is constrained. This happens for example in the function call
9815 -- and explicit dereference cases. In these cases, we have to get
9816 -- the length or range from the expression itself, making sure we
9817 -- do not evaluate it more than once.
9819 -- Here Ck_Node is the original expression, or more properly the
9820 -- result of applying Duplicate_Expr to the original tree, forcing
9821 -- the result to be a name.
9825 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
9828 -- Build the condition for the explicit dereference case
9830 for Indx
in 1 .. Ndims
loop
9832 (Cond
, Length_N_Cond
(Ck_Node
, T_Typ
, Indx
));
9839 -- Construct the test and insert into the tree
9841 if Present
(Cond
) then
9843 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
9847 (Make_Raise_Constraint_Error
(Loc
,
9849 Reason
=> CE_Length_Check_Failed
));
9853 end Selected_Length_Checks
;
9855 ---------------------------
9856 -- Selected_Range_Checks --
9857 ---------------------------
9859 function Selected_Range_Checks
9861 Target_Typ
: Entity_Id
;
9862 Source_Typ
: Entity_Id
;
9863 Warn_Node
: Node_Id
) return Check_Result
9865 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
9868 Expr_Actual
: Node_Id
;
9870 Cond
: Node_Id
:= Empty
;
9871 Do_Access
: Boolean := False;
9872 Wnode
: Node_Id
:= Warn_Node
;
9873 Ret_Result
: Check_Result
:= (Empty
, Empty
);
9874 Num_Checks
: Natural := 0;
9876 procedure Add_Check
(N
: Node_Id
);
9877 -- Adds the action given to Ret_Result if N is non-Empty
9879 function Discrete_Range_Cond
9881 Typ
: Entity_Id
) return Node_Id
;
9882 -- Returns expression to compute:
9883 -- Low_Bound (Expr) < Typ'First
9885 -- High_Bound (Expr) > Typ'Last
9887 function Discrete_Expr_Cond
9889 Typ
: Entity_Id
) return Node_Id
;
9890 -- Returns expression to compute:
9895 function Get_E_First_Or_Last
9899 Nam
: Name_Id
) return Node_Id
;
9900 -- Returns an attribute reference
9901 -- E'First or E'Last
9902 -- with a source location of Loc.
9904 -- Nam is Name_First or Name_Last, according to which attribute is
9905 -- desired. If Indx is non-zero, it is passed as a literal in the
9906 -- Expressions of the attribute reference (identifying the desired
9907 -- array dimension).
9909 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
9910 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
9911 -- Returns expression to compute:
9912 -- N'First or N'Last using Duplicate_Subexpr_No_Checks
9914 function Range_E_Cond
9915 (Exptyp
: Entity_Id
;
9919 -- Returns expression to compute:
9920 -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
9922 function Range_Equal_E_Cond
9923 (Exptyp
: Entity_Id
;
9925 Indx
: Nat
) return Node_Id
;
9926 -- Returns expression to compute:
9927 -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
9929 function Range_N_Cond
9932 Indx
: Nat
) return Node_Id
;
9933 -- Return expression to compute:
9934 -- Expr'First < Typ'First or else Expr'Last > Typ'Last
9940 procedure Add_Check
(N
: Node_Id
) is
9944 -- For now, ignore attempt to place more than 2 checks ???
9946 if Num_Checks
= 2 then
9950 pragma Assert
(Num_Checks
<= 1);
9951 Num_Checks
:= Num_Checks
+ 1;
9952 Ret_Result
(Num_Checks
) := N
;
9956 -------------------------
9957 -- Discrete_Expr_Cond --
9958 -------------------------
9960 function Discrete_Expr_Cond
9962 Typ
: Entity_Id
) return Node_Id
9970 Convert_To
(Base_Type
(Typ
),
9971 Duplicate_Subexpr_No_Checks
(Expr
)),
9973 Convert_To
(Base_Type
(Typ
),
9974 Get_E_First_Or_Last
(Loc
, Typ
, 0, Name_First
))),
9979 Convert_To
(Base_Type
(Typ
),
9980 Duplicate_Subexpr_No_Checks
(Expr
)),
9984 Get_E_First_Or_Last
(Loc
, Typ
, 0, Name_Last
))));
9985 end Discrete_Expr_Cond
;
9987 -------------------------
9988 -- Discrete_Range_Cond --
9989 -------------------------
9991 function Discrete_Range_Cond
9993 Typ
: Entity_Id
) return Node_Id
9995 LB
: Node_Id
:= Low_Bound
(Expr
);
9996 HB
: Node_Id
:= High_Bound
(Expr
);
9998 Left_Opnd
: Node_Id
;
9999 Right_Opnd
: Node_Id
;
10002 if Nkind
(LB
) = N_Identifier
10003 and then Ekind
(Entity
(LB
)) = E_Discriminant
10005 LB
:= New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
10012 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(LB
)),
10017 Get_E_First_Or_Last
(Loc
, Typ
, 0, Name_First
)));
10019 if Nkind
(HB
) = N_Identifier
10020 and then Ekind
(Entity
(HB
)) = E_Discriminant
10022 HB
:= New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
10029 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(HB
)),
10034 Get_E_First_Or_Last
(Loc
, Typ
, 0, Name_Last
)));
10036 return Make_Or_Else
(Loc
, Left_Opnd
, Right_Opnd
);
10037 end Discrete_Range_Cond
;
10039 -------------------------
10040 -- Get_E_First_Or_Last --
10041 -------------------------
10043 function Get_E_First_Or_Last
10047 Nam
: Name_Id
) return Node_Id
10052 Exprs
:= New_List
(Make_Integer_Literal
(Loc
, UI_From_Int
(Indx
)));
10057 return Make_Attribute_Reference
(Loc
,
10058 Prefix
=> New_Occurrence_Of
(E
, Loc
),
10059 Attribute_Name
=> Nam
,
10060 Expressions
=> Exprs
);
10061 end Get_E_First_Or_Last
;
10067 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
10070 Make_Attribute_Reference
(Loc
,
10071 Attribute_Name
=> Name_First
,
10073 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
10074 Expressions
=> New_List
(
10075 Make_Integer_Literal
(Loc
, Indx
)));
10082 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
10085 Make_Attribute_Reference
(Loc
,
10086 Attribute_Name
=> Name_Last
,
10088 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
10089 Expressions
=> New_List
(
10090 Make_Integer_Literal
(Loc
, Indx
)));
10097 function Range_E_Cond
10098 (Exptyp
: Entity_Id
;
10100 Indx
: Nat
) return Node_Id
10108 Get_E_First_Or_Last
(Loc
, Exptyp
, Indx
, Name_First
),
10110 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_First
)),
10115 Get_E_First_Or_Last
(Loc
, Exptyp
, Indx
, Name_Last
),
10117 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_Last
)));
10120 ------------------------
10121 -- Range_Equal_E_Cond --
10122 ------------------------
10124 function Range_Equal_E_Cond
10125 (Exptyp
: Entity_Id
;
10127 Indx
: Nat
) return Node_Id
10135 Get_E_First_Or_Last
(Loc
, Exptyp
, Indx
, Name_First
),
10137 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_First
)),
10142 Get_E_First_Or_Last
(Loc
, Exptyp
, Indx
, Name_Last
),
10144 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_Last
)));
10145 end Range_Equal_E_Cond
;
10151 function Range_N_Cond
10154 Indx
: Nat
) return Node_Id
10162 Get_N_First
(Expr
, Indx
),
10164 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_First
)),
10169 Get_N_Last
(Expr
, Indx
),
10171 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_Last
)));
10174 -- Start of processing for Selected_Range_Checks
10177 -- Checks will be applied only when generating code. In GNATprove mode,
10178 -- we do not apply the checks, but we still call Selected_Range_Checks
10179 -- to possibly issue errors on SPARK code when a run-time error can be
10180 -- detected at compile time.
10182 if not Expander_Active
and not GNATprove_Mode
then
10186 if Target_Typ
= Any_Type
10187 or else Target_Typ
= Any_Composite
10188 or else Raises_Constraint_Error
(Ck_Node
)
10197 T_Typ
:= Target_Typ
;
10199 if No
(Source_Typ
) then
10200 S_Typ
:= Etype
(Ck_Node
);
10202 S_Typ
:= Source_Typ
;
10205 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
10209 -- The order of evaluating T_Typ before S_Typ seems to be critical
10210 -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
10211 -- in, and since Node can be an N_Range node, it might be invalid.
10212 -- Should there be an assert check somewhere for taking the Etype of
10213 -- an N_Range node ???
10215 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
10216 S_Typ
:= Designated_Type
(S_Typ
);
10217 T_Typ
:= Designated_Type
(T_Typ
);
10220 -- A simple optimization for the null case
10222 if Known_Null
(Ck_Node
) then
10227 -- For an N_Range Node, check for a null range and then if not
10228 -- null generate a range check action.
10230 if Nkind
(Ck_Node
) = N_Range
then
10232 -- There's no point in checking a range against itself
10234 if Ck_Node
= Scalar_Range
(T_Typ
) then
10239 T_LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
10240 T_HB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
10241 Known_T_LB
: constant Boolean := Compile_Time_Known_Value
(T_LB
);
10242 Known_T_HB
: constant Boolean := Compile_Time_Known_Value
(T_HB
);
10244 LB
: Node_Id
:= Low_Bound
(Ck_Node
);
10245 HB
: Node_Id
:= High_Bound
(Ck_Node
);
10246 Known_LB
: Boolean := False;
10247 Known_HB
: Boolean := False;
10249 Null_Range
: Boolean;
10250 Out_Of_Range_L
: Boolean;
10251 Out_Of_Range_H
: Boolean;
10254 -- Compute what is known at compile time
10256 if Known_T_LB
and Known_T_HB
then
10257 if Compile_Time_Known_Value
(LB
) then
10260 -- There's no point in checking that a bound is within its
10261 -- own range so pretend that it is known in this case. First
10262 -- deal with low bound.
10264 elsif Ekind
(Etype
(LB
)) = E_Signed_Integer_Subtype
10265 and then Scalar_Range
(Etype
(LB
)) = Scalar_Range
(T_Typ
)
10271 -- Likewise for the high bound
10273 if Compile_Time_Known_Value
(HB
) then
10276 elsif Ekind
(Etype
(HB
)) = E_Signed_Integer_Subtype
10277 and then Scalar_Range
(Etype
(HB
)) = Scalar_Range
(T_Typ
)
10284 -- Check for case where everything is static and we can do the
10285 -- check at compile time. This is skipped if we have an access
10286 -- type, since the access value may be null.
10288 -- ??? This code can be improved since you only need to know that
10289 -- the two respective bounds (LB & T_LB or HB & T_HB) are known at
10290 -- compile time to emit pertinent messages.
10292 if Known_T_LB
and Known_T_HB
and Known_LB
and Known_HB
10295 -- Floating-point case
10297 if Is_Floating_Point_Type
(S_Typ
) then
10298 Null_Range
:= Expr_Value_R
(HB
) < Expr_Value_R
(LB
);
10300 (Expr_Value_R
(LB
) < Expr_Value_R
(T_LB
))
10302 (Expr_Value_R
(LB
) > Expr_Value_R
(T_HB
));
10305 (Expr_Value_R
(HB
) > Expr_Value_R
(T_HB
))
10307 (Expr_Value_R
(HB
) < Expr_Value_R
(T_LB
));
10309 -- Fixed or discrete type case
10312 Null_Range
:= Expr_Value
(HB
) < Expr_Value
(LB
);
10314 (Expr_Value
(LB
) < Expr_Value
(T_LB
))
10316 (Expr_Value
(LB
) > Expr_Value
(T_HB
));
10319 (Expr_Value
(HB
) > Expr_Value
(T_HB
))
10321 (Expr_Value
(HB
) < Expr_Value
(T_LB
));
10324 if not Null_Range
then
10325 if Out_Of_Range_L
then
10326 if No
(Warn_Node
) then
10328 (Compile_Time_Constraint_Error
10329 (Low_Bound
(Ck_Node
),
10330 "static value out of range of}??", T_Typ
));
10334 (Compile_Time_Constraint_Error
10336 "static range out of bounds of}??", T_Typ
));
10340 if Out_Of_Range_H
then
10341 if No
(Warn_Node
) then
10343 (Compile_Time_Constraint_Error
10344 (High_Bound
(Ck_Node
),
10345 "static value out of range of}??", T_Typ
));
10349 (Compile_Time_Constraint_Error
10351 "static range out of bounds of}??", T_Typ
));
10358 LB
: Node_Id
:= Low_Bound
(Ck_Node
);
10359 HB
: Node_Id
:= High_Bound
(Ck_Node
);
10362 -- If either bound is a discriminant and we are within the
10363 -- record declaration, it is a use of the discriminant in a
10364 -- constraint of a component, and nothing can be checked
10365 -- here. The check will be emitted within the init proc.
10366 -- Before then, the discriminal has no real meaning.
10367 -- Similarly, if the entity is a discriminal, there is no
10368 -- check to perform yet.
10370 -- The same holds within a discriminated synchronized type,
10371 -- where the discriminant may constrain a component or an
10374 if Nkind
(LB
) = N_Identifier
10375 and then Denotes_Discriminant
(LB
, True)
10377 if Current_Scope
= Scope
(Entity
(LB
))
10378 or else Is_Concurrent_Type
(Current_Scope
)
10379 or else Ekind
(Entity
(LB
)) /= E_Discriminant
10384 New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
10388 if Nkind
(HB
) = N_Identifier
10389 and then Denotes_Discriminant
(HB
, True)
10391 if Current_Scope
= Scope
(Entity
(HB
))
10392 or else Is_Concurrent_Type
(Current_Scope
)
10393 or else Ekind
(Entity
(HB
)) /= E_Discriminant
10398 New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
10402 Cond
:= Discrete_Range_Cond
(Ck_Node
, T_Typ
);
10403 Set_Paren_Count
(Cond
, 1);
10406 Make_And_Then
(Loc
,
10410 Convert_To
(Base_Type
(Etype
(HB
)),
10411 Duplicate_Subexpr_No_Checks
(HB
)),
10413 Convert_To
(Base_Type
(Etype
(LB
)),
10414 Duplicate_Subexpr_No_Checks
(LB
))),
10415 Right_Opnd
=> Cond
);
10420 elsif Is_Scalar_Type
(S_Typ
) then
10422 -- This somewhat duplicates what Apply_Scalar_Range_Check does,
10423 -- except the above simply sets a flag in the node and lets
10424 -- gigi generate the check base on the Etype of the expression.
10425 -- Sometimes, however we want to do a dynamic check against an
10426 -- arbitrary target type, so we do that here.
10428 if Ekind
(Base_Type
(S_Typ
)) /= Ekind
(Base_Type
(T_Typ
)) then
10429 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
10431 -- For literals, we can tell if the constraint error will be
10432 -- raised at compile time, so we never need a dynamic check, but
10433 -- if the exception will be raised, then post the usual warning,
10434 -- and replace the literal with a raise constraint error
10435 -- expression. As usual, skip this for access types
10437 elsif Compile_Time_Known_Value
(Ck_Node
) and then not Do_Access
then
10439 LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
10440 UB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
10442 Out_Of_Range
: Boolean;
10443 Static_Bounds
: constant Boolean :=
10444 Compile_Time_Known_Value
(LB
)
10445 and Compile_Time_Known_Value
(UB
);
10448 -- Following range tests should use Sem_Eval routine ???
10450 if Static_Bounds
then
10451 if Is_Floating_Point_Type
(S_Typ
) then
10453 (Expr_Value_R
(Ck_Node
) < Expr_Value_R
(LB
))
10455 (Expr_Value_R
(Ck_Node
) > Expr_Value_R
(UB
));
10457 -- Fixed or discrete type
10461 Expr_Value
(Ck_Node
) < Expr_Value
(LB
)
10463 Expr_Value
(Ck_Node
) > Expr_Value
(UB
);
10466 -- Bounds of the type are static and the literal is out of
10467 -- range so output a warning message.
10469 if Out_Of_Range
then
10470 if No
(Warn_Node
) then
10472 (Compile_Time_Constraint_Error
10474 "static value out of range of}??", T_Typ
));
10478 (Compile_Time_Constraint_Error
10480 "static value out of range of}??", T_Typ
));
10485 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
10489 -- Here for the case of a non-static expression, we need a runtime
10490 -- check unless the source type range is guaranteed to be in the
10491 -- range of the target type.
10494 if not In_Subrange_Of
(S_Typ
, T_Typ
) then
10495 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
10500 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
10501 if Is_Constrained
(T_Typ
) then
10503 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
10504 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
10506 if Is_Access_Type
(Exptyp
) then
10507 Exptyp
:= Designated_Type
(Exptyp
);
10510 -- String_Literal case. This needs to be handled specially be-
10511 -- cause no index types are available for string literals. The
10512 -- condition is simply:
10514 -- T_Typ'Length = string-literal-length
10516 if Nkind
(Expr_Actual
) = N_String_Literal
then
10519 -- General array case. Here we have a usable actual subtype for
10520 -- the expression, and the condition is built from the two types
10522 -- T_Typ'First < Exptyp'First or else
10523 -- T_Typ'Last > Exptyp'Last or else
10524 -- T_Typ'First(1) < Exptyp'First(1) or else
10525 -- T_Typ'Last(1) > Exptyp'Last(1) or else
10528 elsif Is_Constrained
(Exptyp
) then
10530 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
10536 L_Index
:= First_Index
(T_Typ
);
10537 R_Index
:= First_Index
(Exptyp
);
10539 for Indx
in 1 .. Ndims
loop
10540 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
10542 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
10544 -- Deal with compile time length check. Note that we
10545 -- skip this in the access case, because the access
10546 -- value may be null, so we cannot know statically.
10549 Subtypes_Statically_Match
10550 (Etype
(L_Index
), Etype
(R_Index
))
10552 -- If the target type is constrained then we
10553 -- have to check for exact equality of bounds
10554 -- (required for qualified expressions).
10556 if Is_Constrained
(T_Typ
) then
10559 Range_Equal_E_Cond
(Exptyp
, T_Typ
, Indx
));
10562 (Cond
, Range_E_Cond
(Exptyp
, T_Typ
, Indx
));
10572 -- Handle cases where we do not get a usable actual subtype that
10573 -- is constrained. This happens for example in the function call
10574 -- and explicit dereference cases. In these cases, we have to get
10575 -- the length or range from the expression itself, making sure we
10576 -- do not evaluate it more than once.
10578 -- Here Ck_Node is the original expression, or more properly the
10579 -- result of applying Duplicate_Expr to the original tree,
10580 -- forcing the result to be a name.
10584 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
10587 -- Build the condition for the explicit dereference case
10589 for Indx
in 1 .. Ndims
loop
10591 (Cond
, Range_N_Cond
(Ck_Node
, T_Typ
, Indx
));
10597 -- For a conversion to an unconstrained array type, generate an
10598 -- Action to check that the bounds of the source value are within
10599 -- the constraints imposed by the target type (RM 4.6(38)). No
10600 -- check is needed for a conversion to an access to unconstrained
10601 -- array type, as 4.6(24.15/2) requires the designated subtypes
10602 -- of the two access types to statically match.
10604 if Nkind
(Parent
(Ck_Node
)) = N_Type_Conversion
10605 and then not Do_Access
10608 Opnd_Index
: Node_Id
;
10609 Targ_Index
: Node_Id
;
10610 Opnd_Range
: Node_Id
;
10613 Opnd_Index
:= First_Index
(Get_Actual_Subtype
(Ck_Node
));
10614 Targ_Index
:= First_Index
(T_Typ
);
10615 while Present
(Opnd_Index
) loop
10617 -- If the index is a range, use its bounds. If it is an
10618 -- entity (as will be the case if it is a named subtype
10619 -- or an itype created for a slice) retrieve its range.
10621 if Is_Entity_Name
(Opnd_Index
)
10622 and then Is_Type
(Entity
(Opnd_Index
))
10624 Opnd_Range
:= Scalar_Range
(Entity
(Opnd_Index
));
10626 Opnd_Range
:= Opnd_Index
;
10629 if Nkind
(Opnd_Range
) = N_Range
then
10631 (Low_Bound
(Opnd_Range
), Etype
(Targ_Index
),
10632 Assume_Valid
=> True)
10635 (High_Bound
(Opnd_Range
), Etype
(Targ_Index
),
10636 Assume_Valid
=> True)
10640 -- If null range, no check needed
10643 Compile_Time_Known_Value
(High_Bound
(Opnd_Range
))
10645 Compile_Time_Known_Value
(Low_Bound
(Opnd_Range
))
10647 Expr_Value
(High_Bound
(Opnd_Range
)) <
10648 Expr_Value
(Low_Bound
(Opnd_Range
))
10652 elsif Is_Out_Of_Range
10653 (Low_Bound
(Opnd_Range
), Etype
(Targ_Index
),
10654 Assume_Valid
=> True)
10657 (High_Bound
(Opnd_Range
), Etype
(Targ_Index
),
10658 Assume_Valid
=> True)
10661 (Compile_Time_Constraint_Error
10662 (Wnode
, "value out of range of}??", T_Typ
));
10667 Discrete_Range_Cond
10668 (Opnd_Range
, Etype
(Targ_Index
)));
10672 Next_Index
(Opnd_Index
);
10673 Next_Index
(Targ_Index
);
10680 -- Construct the test and insert into the tree
10682 if Present
(Cond
) then
10684 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
10688 (Make_Raise_Constraint_Error
(Loc
,
10690 Reason
=> CE_Range_Check_Failed
));
10694 end Selected_Range_Checks
;
10696 -------------------------------
10697 -- Storage_Checks_Suppressed --
10698 -------------------------------
10700 function Storage_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
10702 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
10703 return Is_Check_Suppressed
(E
, Storage_Check
);
10705 return Scope_Suppress
.Suppress
(Storage_Check
);
10707 end Storage_Checks_Suppressed
;
10709 ---------------------------
10710 -- Tag_Checks_Suppressed --
10711 ---------------------------
10713 function Tag_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
10716 and then Checks_May_Be_Suppressed
(E
)
10718 return Is_Check_Suppressed
(E
, Tag_Check
);
10720 return Scope_Suppress
.Suppress
(Tag_Check
);
10722 end Tag_Checks_Suppressed
;
10724 ---------------------------------------
10725 -- Validate_Alignment_Check_Warnings --
10726 ---------------------------------------
10728 procedure Validate_Alignment_Check_Warnings
is
10730 for J
in Alignment_Warnings
.First
.. Alignment_Warnings
.Last
loop
10732 AWR
: Alignment_Warnings_Record
10733 renames Alignment_Warnings
.Table
(J
);
10735 if Known_Alignment
(AWR
.E
)
10736 and then AWR
.A
mod Alignment
(AWR
.E
) = 0
10738 Delete_Warning_And_Continuations
(AWR
.W
);
10742 end Validate_Alignment_Check_Warnings
;
10744 --------------------------
10745 -- Validity_Check_Range --
10746 --------------------------
10748 procedure Validity_Check_Range
10750 Related_Id
: Entity_Id
:= Empty
)
10753 if Validity_Checks_On
and Validity_Check_Operands
then
10754 if Nkind
(N
) = N_Range
then
10756 (Expr
=> Low_Bound
(N
),
10757 Related_Id
=> Related_Id
,
10758 Is_Low_Bound
=> True);
10761 (Expr
=> High_Bound
(N
),
10762 Related_Id
=> Related_Id
,
10763 Is_High_Bound
=> True);
10766 end Validity_Check_Range
;
10768 --------------------------------
10769 -- Validity_Checks_Suppressed --
10770 --------------------------------
10772 function Validity_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
10774 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
10775 return Is_Check_Suppressed
(E
, Validity_Check
);
10777 return Scope_Suppress
.Suppress
(Validity_Check
);
10779 end Validity_Checks_Suppressed
;