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
);
1881 and then not Backend_Divide_Checks_On_Target
1882 and then Check_Needed
(Right
, Division_Check
)
1884 -- See if division by zero possible, and if so generate test. This
1885 -- part of the test is not controlled by the -gnato switch, since it
1886 -- is a Division_Check and not an Overflow_Check.
1888 and then Do_Division_Check
(N
)
1890 Set_Do_Division_Check
(N
, False);
1892 if (not ROK
) or else (Rlo
<= 0 and then 0 <= Rhi
) then
1893 if Is_Floating_Point_Type
(Etype
(N
)) then
1894 Opnd
:= Make_Real_Literal
(Loc
, Ureal_0
);
1896 Opnd
:= Make_Integer_Literal
(Loc
, 0);
1900 Make_Raise_Constraint_Error
(Loc
,
1903 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(Right
),
1904 Right_Opnd
=> Opnd
),
1905 Reason
=> CE_Divide_By_Zero
));
1908 end Apply_Division_Check
;
1910 ----------------------------------
1911 -- Apply_Float_Conversion_Check --
1912 ----------------------------------
1914 -- Let F and I be the source and target types of the conversion. The RM
1915 -- specifies that a floating-point value X is rounded to the nearest
1916 -- integer, with halfway cases being rounded away from zero. The rounded
1917 -- value of X is checked against I'Range.
1919 -- The catch in the above paragraph is that there is no good way to know
1920 -- whether the round-to-integer operation resulted in overflow. A remedy is
1921 -- to perform a range check in the floating-point domain instead, however:
1923 -- (1) The bounds may not be known at compile time
1924 -- (2) The check must take into account rounding or truncation.
1925 -- (3) The range of type I may not be exactly representable in F.
1926 -- (4) For the rounding case, The end-points I'First - 0.5 and
1927 -- I'Last + 0.5 may or may not be in range, depending on the
1928 -- sign of I'First and I'Last.
1929 -- (5) X may be a NaN, which will fail any comparison
1931 -- The following steps correctly convert X with rounding:
1933 -- (1) If either I'First or I'Last is not known at compile time, use
1934 -- I'Base instead of I in the next three steps and perform a
1935 -- regular range check against I'Range after conversion.
1936 -- (2) If I'First - 0.5 is representable in F then let Lo be that
1937 -- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be
1938 -- F'Machine (I'First) and let Lo_OK be (Lo >= I'First).
1939 -- In other words, take one of the closest floating-point numbers
1940 -- (which is an integer value) to I'First, and see if it is in
1942 -- (3) If I'Last + 0.5 is representable in F then let Hi be that value
1943 -- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be
1944 -- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last).
1945 -- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo)
1946 -- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi)
1948 -- For the truncating case, replace steps (2) and (3) as follows:
1949 -- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK
1950 -- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let
1952 -- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK
1953 -- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let
1956 procedure Apply_Float_Conversion_Check
1958 Target_Typ
: Entity_Id
)
1960 LB
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
1961 HB
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
1962 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
1963 Expr_Type
: constant Entity_Id
:= Base_Type
(Etype
(Ck_Node
));
1964 Target_Base
: constant Entity_Id
:=
1965 Implementation_Base_Type
(Target_Typ
);
1967 Par
: constant Node_Id
:= Parent
(Ck_Node
);
1968 pragma Assert
(Nkind
(Par
) = N_Type_Conversion
);
1969 -- Parent of check node, must be a type conversion
1971 Truncate
: constant Boolean := Float_Truncate
(Par
);
1972 Max_Bound
: constant Uint
:=
1974 (Machine_Radix_Value
(Expr_Type
),
1975 Machine_Mantissa_Value
(Expr_Type
) - 1) - 1;
1977 -- Largest bound, so bound plus or minus half is a machine number of F
1979 Ifirst
, Ilast
: Uint
;
1980 -- Bounds of integer type
1983 -- Bounds to check in floating-point domain
1985 Lo_OK
, Hi_OK
: Boolean;
1986 -- True iff Lo resp. Hi belongs to I'Range
1988 Lo_Chk
, Hi_Chk
: Node_Id
;
1989 -- Expressions that are False iff check fails
1991 Reason
: RT_Exception_Code
;
1994 -- We do not need checks if we are not generating code (i.e. the full
1995 -- expander is not active). In SPARK mode, we specifically don't want
1996 -- the frontend to expand these checks, which are dealt with directly
1997 -- in the formal verification backend.
1999 if not Expander_Active
then
2003 if not Compile_Time_Known_Value
(LB
)
2004 or not Compile_Time_Known_Value
(HB
)
2007 -- First check that the value falls in the range of the base type,
2008 -- to prevent overflow during conversion and then perform a
2009 -- regular range check against the (dynamic) bounds.
2011 pragma Assert
(Target_Base
/= Target_Typ
);
2013 Temp
: constant Entity_Id
:= Make_Temporary
(Loc
, 'T', Par
);
2016 Apply_Float_Conversion_Check
(Ck_Node
, Target_Base
);
2017 Set_Etype
(Temp
, Target_Base
);
2019 Insert_Action
(Parent
(Par
),
2020 Make_Object_Declaration
(Loc
,
2021 Defining_Identifier
=> Temp
,
2022 Object_Definition
=> New_Occurrence_Of
(Target_Typ
, Loc
),
2023 Expression
=> New_Copy_Tree
(Par
)),
2024 Suppress
=> All_Checks
);
2027 Make_Raise_Constraint_Error
(Loc
,
2030 Left_Opnd
=> New_Occurrence_Of
(Temp
, Loc
),
2031 Right_Opnd
=> New_Occurrence_Of
(Target_Typ
, Loc
)),
2032 Reason
=> CE_Range_Check_Failed
));
2033 Rewrite
(Par
, New_Occurrence_Of
(Temp
, Loc
));
2039 -- Get the (static) bounds of the target type
2041 Ifirst
:= Expr_Value
(LB
);
2042 Ilast
:= Expr_Value
(HB
);
2044 -- A simple optimization: if the expression is a universal literal,
2045 -- we can do the comparison with the bounds and the conversion to
2046 -- an integer type statically. The range checks are unchanged.
2048 if Nkind
(Ck_Node
) = N_Real_Literal
2049 and then Etype
(Ck_Node
) = Universal_Real
2050 and then Is_Integer_Type
(Target_Typ
)
2051 and then Nkind
(Parent
(Ck_Node
)) = N_Type_Conversion
2054 Int_Val
: constant Uint
:= UR_To_Uint
(Realval
(Ck_Node
));
2057 if Int_Val
<= Ilast
and then Int_Val
>= Ifirst
then
2059 -- Conversion is safe
2061 Rewrite
(Parent
(Ck_Node
),
2062 Make_Integer_Literal
(Loc
, UI_To_Int
(Int_Val
)));
2063 Analyze_And_Resolve
(Parent
(Ck_Node
), Target_Typ
);
2069 -- Check against lower bound
2071 if Truncate
and then Ifirst
> 0 then
2072 Lo
:= Pred
(Expr_Type
, UR_From_Uint
(Ifirst
));
2076 Lo
:= Succ
(Expr_Type
, UR_From_Uint
(Ifirst
- 1));
2079 elsif abs (Ifirst
) < Max_Bound
then
2080 Lo
:= UR_From_Uint
(Ifirst
) - Ureal_Half
;
2081 Lo_OK
:= (Ifirst
> 0);
2084 Lo
:= Machine
(Expr_Type
, UR_From_Uint
(Ifirst
), Round_Even
, Ck_Node
);
2085 Lo_OK
:= (Lo
>= UR_From_Uint
(Ifirst
));
2090 -- Lo_Chk := (X >= Lo)
2092 Lo_Chk
:= Make_Op_Ge
(Loc
,
2093 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
2094 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
2097 -- Lo_Chk := (X > Lo)
2099 Lo_Chk
:= Make_Op_Gt
(Loc
,
2100 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
2101 Right_Opnd
=> Make_Real_Literal
(Loc
, Lo
));
2104 -- Check against higher bound
2106 if Truncate
and then Ilast
< 0 then
2107 Hi
:= Succ
(Expr_Type
, UR_From_Uint
(Ilast
));
2111 Hi
:= Pred
(Expr_Type
, UR_From_Uint
(Ilast
+ 1));
2114 elsif abs (Ilast
) < Max_Bound
then
2115 Hi
:= UR_From_Uint
(Ilast
) + Ureal_Half
;
2116 Hi_OK
:= (Ilast
< 0);
2118 Hi
:= Machine
(Expr_Type
, UR_From_Uint
(Ilast
), Round_Even
, Ck_Node
);
2119 Hi_OK
:= (Hi
<= UR_From_Uint
(Ilast
));
2124 -- Hi_Chk := (X <= Hi)
2126 Hi_Chk
:= Make_Op_Le
(Loc
,
2127 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
2128 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
2131 -- Hi_Chk := (X < Hi)
2133 Hi_Chk
:= Make_Op_Lt
(Loc
,
2134 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
2135 Right_Opnd
=> Make_Real_Literal
(Loc
, Hi
));
2138 -- If the bounds of the target type are the same as those of the base
2139 -- type, the check is an overflow check as a range check is not
2140 -- performed in these cases.
2142 if Expr_Value
(Type_Low_Bound
(Target_Base
)) = Ifirst
2143 and then Expr_Value
(Type_High_Bound
(Target_Base
)) = Ilast
2145 Reason
:= CE_Overflow_Check_Failed
;
2147 Reason
:= CE_Range_Check_Failed
;
2150 -- Raise CE if either conditions does not hold
2152 Insert_Action
(Ck_Node
,
2153 Make_Raise_Constraint_Error
(Loc
,
2154 Condition
=> Make_Op_Not
(Loc
, Make_And_Then
(Loc
, Lo_Chk
, Hi_Chk
)),
2156 end Apply_Float_Conversion_Check
;
2158 ------------------------
2159 -- Apply_Length_Check --
2160 ------------------------
2162 procedure Apply_Length_Check
2164 Target_Typ
: Entity_Id
;
2165 Source_Typ
: Entity_Id
:= Empty
)
2168 Apply_Selected_Length_Checks
2169 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
2170 end Apply_Length_Check
;
2172 -------------------------------------
2173 -- Apply_Parameter_Aliasing_Checks --
2174 -------------------------------------
2176 procedure Apply_Parameter_Aliasing_Checks
2180 Loc
: constant Source_Ptr
:= Sloc
(Call
);
2182 function May_Cause_Aliasing
2183 (Formal_1
: Entity_Id
;
2184 Formal_2
: Entity_Id
) return Boolean;
2185 -- Determine whether two formal parameters can alias each other
2186 -- depending on their modes.
2188 function Original_Actual
(N
: Node_Id
) return Node_Id
;
2189 -- The expander may replace an actual with a temporary for the sake of
2190 -- side effect removal. The temporary may hide a potential aliasing as
2191 -- it does not share the address of the actual. This routine attempts
2192 -- to retrieve the original actual.
2194 procedure Overlap_Check
2195 (Actual_1
: Node_Id
;
2197 Formal_1
: Entity_Id
;
2198 Formal_2
: Entity_Id
;
2199 Check
: in out Node_Id
);
2200 -- Create a check to determine whether Actual_1 overlaps with Actual_2.
2201 -- If detailed exception messages are enabled, the check is augmented to
2202 -- provide information about the names of the corresponding formals. See
2203 -- the body for details. Actual_1 and Actual_2 denote the two actuals to
2204 -- be tested. Formal_1 and Formal_2 denote the corresponding formals.
2205 -- Check contains all and-ed simple tests generated so far or remains
2206 -- unchanged in the case of detailed exception messaged.
2208 ------------------------
2209 -- May_Cause_Aliasing --
2210 ------------------------
2212 function May_Cause_Aliasing
2213 (Formal_1
: Entity_Id
;
2214 Formal_2
: Entity_Id
) return Boolean
2217 -- The following combination cannot lead to aliasing
2219 -- Formal 1 Formal 2
2222 if Ekind
(Formal_1
) = E_In_Parameter
2224 Ekind
(Formal_2
) = E_In_Parameter
2228 -- The following combinations may lead to aliasing
2230 -- Formal 1 Formal 2
2240 end May_Cause_Aliasing
;
2242 ---------------------
2243 -- Original_Actual --
2244 ---------------------
2246 function Original_Actual
(N
: Node_Id
) return Node_Id
is
2248 if Nkind
(N
) = N_Type_Conversion
then
2249 return Expression
(N
);
2251 -- The expander created a temporary to capture the result of a type
2252 -- conversion where the expression is the real actual.
2254 elsif Nkind
(N
) = N_Identifier
2255 and then Present
(Original_Node
(N
))
2256 and then Nkind
(Original_Node
(N
)) = N_Type_Conversion
2258 return Expression
(Original_Node
(N
));
2262 end Original_Actual
;
2268 procedure Overlap_Check
2269 (Actual_1
: Node_Id
;
2271 Formal_1
: Entity_Id
;
2272 Formal_2
: Entity_Id
;
2273 Check
: in out Node_Id
)
2276 ID_Casing
: constant Casing_Type
:=
2277 Identifier_Casing
(Source_Index
(Current_Sem_Unit
));
2281 -- Actual_1'Overlaps_Storage (Actual_2)
2284 Make_Attribute_Reference
(Loc
,
2285 Prefix
=> New_Copy_Tree
(Original_Actual
(Actual_1
)),
2286 Attribute_Name
=> Name_Overlaps_Storage
,
2288 New_List
(New_Copy_Tree
(Original_Actual
(Actual_2
))));
2290 -- Generate the following check when detailed exception messages are
2293 -- if Actual_1'Overlaps_Storage (Actual_2) then
2294 -- raise Program_Error with <detailed message>;
2297 if Exception_Extra_Info
then
2300 -- Do not generate location information for internal calls
2302 if Comes_From_Source
(Call
) then
2303 Store_String_Chars
(Build_Location_String
(Loc
));
2304 Store_String_Char
(' ');
2307 Store_String_Chars
("aliased parameters, actuals for """);
2309 Get_Name_String
(Chars
(Formal_1
));
2310 Set_Casing
(ID_Casing
);
2311 Store_String_Chars
(Name_Buffer
(1 .. Name_Len
));
2313 Store_String_Chars
(""" and """);
2315 Get_Name_String
(Chars
(Formal_2
));
2316 Set_Casing
(ID_Casing
);
2317 Store_String_Chars
(Name_Buffer
(1 .. Name_Len
));
2319 Store_String_Chars
(""" overlap");
2321 Insert_Action
(Call
,
2322 Make_If_Statement
(Loc
,
2324 Then_Statements
=> New_List
(
2325 Make_Raise_Statement
(Loc
,
2327 New_Occurrence_Of
(Standard_Program_Error
, Loc
),
2328 Expression
=> Make_String_Literal
(Loc
, End_String
)))));
2330 -- Create a sequence of overlapping checks by and-ing them all
2340 Right_Opnd
=> Cond
);
2350 Formal_1
: Entity_Id
;
2351 Formal_2
: Entity_Id
;
2352 Orig_Act_1
: Node_Id
;
2353 Orig_Act_2
: Node_Id
;
2355 -- Start of processing for Apply_Parameter_Aliasing_Checks
2360 Actual_1
:= First_Actual
(Call
);
2361 Formal_1
:= First_Formal
(Subp
);
2362 while Present
(Actual_1
) and then Present
(Formal_1
) loop
2363 Orig_Act_1
:= Original_Actual
(Actual_1
);
2365 -- Ensure that the actual is an object that is not passed by value.
2366 -- Elementary types are always passed by value, therefore actuals of
2367 -- such types cannot lead to aliasing. An aggregate is an object in
2368 -- Ada 2012, but an actual that is an aggregate cannot overlap with
2369 -- another actual. A type that is By_Reference (such as an array of
2370 -- controlled types) is not subject to the check because any update
2371 -- will be done in place and a subsequent read will always see the
2372 -- correct value, see RM 6.2 (12/3).
2374 if Nkind
(Orig_Act_1
) = N_Aggregate
2375 or else (Nkind
(Orig_Act_1
) = N_Qualified_Expression
2376 and then Nkind
(Expression
(Orig_Act_1
)) = N_Aggregate
)
2380 elsif Is_Object_Reference
(Orig_Act_1
)
2381 and then not Is_Elementary_Type
(Etype
(Orig_Act_1
))
2382 and then not Is_By_Reference_Type
(Etype
(Orig_Act_1
))
2384 Actual_2
:= Next_Actual
(Actual_1
);
2385 Formal_2
:= Next_Formal
(Formal_1
);
2386 while Present
(Actual_2
) and then Present
(Formal_2
) loop
2387 Orig_Act_2
:= Original_Actual
(Actual_2
);
2389 -- The other actual we are testing against must also denote
2390 -- a non pass-by-value object. Generate the check only when
2391 -- the mode of the two formals may lead to aliasing.
2393 if Is_Object_Reference
(Orig_Act_2
)
2394 and then not Is_Elementary_Type
(Etype
(Orig_Act_2
))
2395 and then May_Cause_Aliasing
(Formal_1
, Formal_2
)
2397 Remove_Side_Effects
(Actual_1
);
2398 Remove_Side_Effects
(Actual_2
);
2401 (Actual_1
=> Actual_1
,
2402 Actual_2
=> Actual_2
,
2403 Formal_1
=> Formal_1
,
2404 Formal_2
=> Formal_2
,
2408 Next_Actual
(Actual_2
);
2409 Next_Formal
(Formal_2
);
2413 Next_Actual
(Actual_1
);
2414 Next_Formal
(Formal_1
);
2417 -- Place a simple check right before the call
2419 if Present
(Check
) and then not Exception_Extra_Info
then
2420 Insert_Action
(Call
,
2421 Make_Raise_Program_Error
(Loc
,
2423 Reason
=> PE_Aliased_Parameters
));
2425 end Apply_Parameter_Aliasing_Checks
;
2427 -------------------------------------
2428 -- Apply_Parameter_Validity_Checks --
2429 -------------------------------------
2431 procedure Apply_Parameter_Validity_Checks
(Subp
: Entity_Id
) is
2432 Subp_Decl
: Node_Id
;
2434 procedure Add_Validity_Check
2435 (Formal
: Entity_Id
;
2437 For_Result
: Boolean := False);
2438 -- Add a single 'Valid[_Scalar] check which verifies the initialization
2439 -- of Formal. Prag_Nam denotes the pre or post condition pragma name.
2440 -- Set flag For_Result when to verify the result of a function.
2442 ------------------------
2443 -- Add_Validity_Check --
2444 ------------------------
2446 procedure Add_Validity_Check
2447 (Formal
: Entity_Id
;
2449 For_Result
: Boolean := False)
2451 procedure Build_Pre_Post_Condition
(Expr
: Node_Id
);
2452 -- Create a pre/postcondition pragma that tests expression Expr
2454 ------------------------------
2455 -- Build_Pre_Post_Condition --
2456 ------------------------------
2458 procedure Build_Pre_Post_Condition
(Expr
: Node_Id
) is
2459 Loc
: constant Source_Ptr
:= Sloc
(Subp
);
2467 Pragma_Argument_Associations
=> New_List
(
2468 Make_Pragma_Argument_Association
(Loc
,
2469 Chars
=> Name_Check
,
2470 Expression
=> Expr
)));
2472 -- Add a message unless exception messages are suppressed
2474 if not Exception_Locations_Suppressed
then
2475 Append_To
(Pragma_Argument_Associations
(Prag
),
2476 Make_Pragma_Argument_Association
(Loc
,
2477 Chars
=> Name_Message
,
2479 Make_String_Literal
(Loc
,
2481 & Get_Name_String
(Prag_Nam
)
2483 & Build_Location_String
(Loc
))));
2486 -- Insert the pragma in the tree
2488 if Nkind
(Parent
(Subp_Decl
)) = N_Compilation_Unit
then
2489 Add_Global_Declaration
(Prag
);
2492 -- PPC pragmas associated with subprogram bodies must be inserted
2493 -- in the declarative part of the body.
2495 elsif Nkind
(Subp_Decl
) = N_Subprogram_Body
then
2496 Decls
:= Declarations
(Subp_Decl
);
2500 Set_Declarations
(Subp_Decl
, Decls
);
2503 Prepend_To
(Decls
, Prag
);
2506 -- For subprogram declarations insert the PPC pragma right after
2507 -- the declarative node.
2510 Insert_After_And_Analyze
(Subp_Decl
, Prag
);
2512 end Build_Pre_Post_Condition
;
2516 Loc
: constant Source_Ptr
:= Sloc
(Subp
);
2517 Typ
: constant Entity_Id
:= Etype
(Formal
);
2521 -- Start of processing for Add_Validity_Check
2524 -- For scalars, generate 'Valid test
2526 if Is_Scalar_Type
(Typ
) then
2529 -- For any non-scalar with scalar parts, generate 'Valid_Scalars test
2531 elsif Scalar_Part_Present
(Typ
) then
2532 Nam
:= Name_Valid_Scalars
;
2534 -- No test needed for other cases (no scalars to test)
2540 -- Step 1: Create the expression to verify the validity of the
2543 Check
:= New_Occurrence_Of
(Formal
, Loc
);
2545 -- When processing a function result, use 'Result. Generate
2550 Make_Attribute_Reference
(Loc
,
2552 Attribute_Name
=> Name_Result
);
2556 -- Context['Result]'Valid[_Scalars]
2559 Make_Attribute_Reference
(Loc
,
2561 Attribute_Name
=> Nam
);
2563 -- Step 2: Create a pre or post condition pragma
2565 Build_Pre_Post_Condition
(Check
);
2566 end Add_Validity_Check
;
2571 Subp_Spec
: Node_Id
;
2573 -- Start of processing for Apply_Parameter_Validity_Checks
2576 -- Extract the subprogram specification and declaration nodes
2578 Subp_Spec
:= Parent
(Subp
);
2580 if Nkind
(Subp_Spec
) = N_Defining_Program_Unit_Name
then
2581 Subp_Spec
:= Parent
(Subp_Spec
);
2584 Subp_Decl
:= Parent
(Subp_Spec
);
2586 if not Comes_From_Source
(Subp
)
2588 -- Do not process formal subprograms because the corresponding actual
2589 -- will receive the proper checks when the instance is analyzed.
2591 or else Is_Formal_Subprogram
(Subp
)
2593 -- Do not process imported subprograms since pre and postconditions
2594 -- are never verified on routines coming from a different language.
2596 or else Is_Imported
(Subp
)
2597 or else Is_Intrinsic_Subprogram
(Subp
)
2599 -- The PPC pragmas generated by this routine do not correspond to
2600 -- source aspects, therefore they cannot be applied to abstract
2603 or else Nkind
(Subp_Decl
) = N_Abstract_Subprogram_Declaration
2605 -- Do not consider subprogram renaminds because the renamed entity
2606 -- already has the proper PPC pragmas.
2608 or else Nkind
(Subp_Decl
) = N_Subprogram_Renaming_Declaration
2610 -- Do not process null procedures because there is no benefit of
2611 -- adding the checks to a no action routine.
2613 or else (Nkind
(Subp_Spec
) = N_Procedure_Specification
2614 and then Null_Present
(Subp_Spec
))
2619 -- Inspect all the formals applying aliasing and scalar initialization
2620 -- checks where applicable.
2622 Formal
:= First_Formal
(Subp
);
2623 while Present
(Formal
) loop
2625 -- Generate the following scalar initialization checks for each
2626 -- formal parameter:
2628 -- mode IN - Pre => Formal'Valid[_Scalars]
2629 -- mode IN OUT - Pre, Post => Formal'Valid[_Scalars]
2630 -- mode OUT - Post => Formal'Valid[_Scalars]
2632 if Check_Validity_Of_Parameters
then
2633 if Ekind_In
(Formal
, E_In_Parameter
, E_In_Out_Parameter
) then
2634 Add_Validity_Check
(Formal
, Name_Precondition
, False);
2637 if Ekind_In
(Formal
, E_In_Out_Parameter
, E_Out_Parameter
) then
2638 Add_Validity_Check
(Formal
, Name_Postcondition
, False);
2642 Next_Formal
(Formal
);
2645 -- Generate following scalar initialization check for function result:
2647 -- Post => Subp'Result'Valid[_Scalars]
2649 if Check_Validity_Of_Parameters
and then Ekind
(Subp
) = E_Function
then
2650 Add_Validity_Check
(Subp
, Name_Postcondition
, True);
2652 end Apply_Parameter_Validity_Checks
;
2654 ---------------------------
2655 -- Apply_Predicate_Check --
2656 ---------------------------
2658 procedure Apply_Predicate_Check
2661 Fun
: Entity_Id
:= Empty
)
2666 if Predicate_Checks_Suppressed
(Empty
) then
2669 elsif Predicates_Ignored
(Typ
) then
2672 elsif Present
(Predicate_Function
(Typ
)) then
2674 while Present
(S
) and then not Is_Subprogram
(S
) loop
2678 -- A predicate check does not apply within internally generated
2679 -- subprograms, such as TSS functions.
2681 if Within_Internal_Subprogram
then
2684 -- If the check appears within the predicate function itself, it
2685 -- means that the user specified a check whose formal is the
2686 -- predicated subtype itself, rather than some covering type. This
2687 -- is likely to be a common error, and thus deserves a warning.
2689 elsif Present
(S
) and then S
= Predicate_Function
(Typ
) then
2691 ("predicate check includes a call to& that requires a "
2692 & "predicate check??", Parent
(N
), Fun
);
2694 ("\this will result in infinite recursion??", Parent
(N
));
2696 if Is_First_Subtype
(Typ
) then
2698 ("\use an explicit subtype of& to carry the predicate",
2703 Make_Raise_Storage_Error
(Sloc
(N
),
2704 Reason
=> SE_Infinite_Recursion
));
2706 -- Here for normal case of predicate active
2709 -- If the type has a static predicate and the expression is known
2710 -- at compile time, see if the expression satisfies the predicate.
2712 Check_Expression_Against_Static_Predicate
(N
, Typ
);
2714 if not Expander_Active
then
2718 -- For an entity of the type, generate a call to the predicate
2719 -- function, unless its type is an actual subtype, which is not
2720 -- visible outside of the enclosing subprogram.
2722 if Is_Entity_Name
(N
)
2723 and then not Is_Actual_Subtype
(Typ
)
2726 Make_Predicate_Check
2727 (Typ
, New_Occurrence_Of
(Entity
(N
), Sloc
(N
))));
2729 -- If the expression is not an entity it may have side effects,
2730 -- and the following call will create an object declaration for
2731 -- it. We disable checks during its analysis, to prevent an
2732 -- infinite recursion.
2734 -- If the prefix is an aggregate in an assignment, apply the
2735 -- check to the LHS after assignment, rather than create a
2736 -- redundant temporary. This is only necessary in rare cases
2737 -- of array types (including strings) initialized with an
2738 -- aggregate with an "others" clause, either coming from source
2739 -- or generated by an Initialize_Scalars pragma.
2741 elsif Nkind
(N
) = N_Aggregate
2742 and then Nkind
(Parent
(N
)) = N_Assignment_Statement
2744 Insert_Action_After
(Parent
(N
),
2745 Make_Predicate_Check
2746 (Typ
, Duplicate_Subexpr
(Name
(Parent
(N
)))));
2750 Make_Predicate_Check
2751 (Typ
, Duplicate_Subexpr
(N
)), Suppress
=> All_Checks
);
2755 end Apply_Predicate_Check
;
2757 -----------------------
2758 -- Apply_Range_Check --
2759 -----------------------
2761 procedure Apply_Range_Check
2763 Target_Typ
: Entity_Id
;
2764 Source_Typ
: Entity_Id
:= Empty
)
2767 Apply_Selected_Range_Checks
2768 (Ck_Node
, Target_Typ
, Source_Typ
, Do_Static
=> False);
2769 end Apply_Range_Check
;
2771 ------------------------------
2772 -- Apply_Scalar_Range_Check --
2773 ------------------------------
2775 -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag
2776 -- off if it is already set on.
2778 procedure Apply_Scalar_Range_Check
2780 Target_Typ
: Entity_Id
;
2781 Source_Typ
: Entity_Id
:= Empty
;
2782 Fixed_Int
: Boolean := False)
2784 Parnt
: constant Node_Id
:= Parent
(Expr
);
2786 Arr
: Node_Id
:= Empty
; -- initialize to prevent warning
2787 Arr_Typ
: Entity_Id
:= Empty
; -- initialize to prevent warning
2789 Is_Subscr_Ref
: Boolean;
2790 -- Set true if Expr is a subscript
2792 Is_Unconstrained_Subscr_Ref
: Boolean;
2793 -- Set true if Expr is a subscript of an unconstrained array. In this
2794 -- case we do not attempt to do an analysis of the value against the
2795 -- range of the subscript, since we don't know the actual subtype.
2798 -- Set to True if Expr should be regarded as a real value even though
2799 -- the type of Expr might be discrete.
2801 procedure Bad_Value
(Warn
: Boolean := False);
2802 -- Procedure called if value is determined to be out of range. Warn is
2803 -- True to force a warning instead of an error, even when SPARK_Mode is
2810 procedure Bad_Value
(Warn
: Boolean := False) is
2812 Apply_Compile_Time_Constraint_Error
2813 (Expr
, "value not in range of}??", CE_Range_Check_Failed
,
2819 -- Start of processing for Apply_Scalar_Range_Check
2822 -- Return if check obviously not needed
2825 -- Not needed inside generic
2829 -- Not needed if previous error
2831 or else Target_Typ
= Any_Type
2832 or else Nkind
(Expr
) = N_Error
2834 -- Not needed for non-scalar type
2836 or else not Is_Scalar_Type
(Target_Typ
)
2838 -- Not needed if we know node raises CE already
2840 or else Raises_Constraint_Error
(Expr
)
2845 -- Now, see if checks are suppressed
2848 Is_List_Member
(Expr
) and then Nkind
(Parnt
) = N_Indexed_Component
;
2850 if Is_Subscr_Ref
then
2851 Arr
:= Prefix
(Parnt
);
2852 Arr_Typ
:= Get_Actual_Subtype_If_Available
(Arr
);
2854 if Is_Access_Type
(Arr_Typ
) then
2855 Arr_Typ
:= Designated_Type
(Arr_Typ
);
2859 if not Do_Range_Check
(Expr
) then
2861 -- Subscript reference. Check for Index_Checks suppressed
2863 if Is_Subscr_Ref
then
2865 -- Check array type and its base type
2867 if Index_Checks_Suppressed
(Arr_Typ
)
2868 or else Index_Checks_Suppressed
(Base_Type
(Arr_Typ
))
2872 -- Check array itself if it is an entity name
2874 elsif Is_Entity_Name
(Arr
)
2875 and then Index_Checks_Suppressed
(Entity
(Arr
))
2879 -- Check expression itself if it is an entity name
2881 elsif Is_Entity_Name
(Expr
)
2882 and then Index_Checks_Suppressed
(Entity
(Expr
))
2887 -- All other cases, check for Range_Checks suppressed
2890 -- Check target type and its base type
2892 if Range_Checks_Suppressed
(Target_Typ
)
2893 or else Range_Checks_Suppressed
(Base_Type
(Target_Typ
))
2897 -- Check expression itself if it is an entity name
2899 elsif Is_Entity_Name
(Expr
)
2900 and then Range_Checks_Suppressed
(Entity
(Expr
))
2904 -- If Expr is part of an assignment statement, then check left
2905 -- side of assignment if it is an entity name.
2907 elsif Nkind
(Parnt
) = N_Assignment_Statement
2908 and then Is_Entity_Name
(Name
(Parnt
))
2909 and then Range_Checks_Suppressed
(Entity
(Name
(Parnt
)))
2916 -- Do not set range checks if they are killed
2918 if Nkind
(Expr
) = N_Unchecked_Type_Conversion
2919 and then Kill_Range_Check
(Expr
)
2924 -- Do not set range checks for any values from System.Scalar_Values
2925 -- since the whole idea of such values is to avoid checking them.
2927 if Is_Entity_Name
(Expr
)
2928 and then Is_RTU
(Scope
(Entity
(Expr
)), System_Scalar_Values
)
2933 -- Now see if we need a check
2935 if No
(Source_Typ
) then
2936 S_Typ
:= Etype
(Expr
);
2938 S_Typ
:= Source_Typ
;
2941 if not Is_Scalar_Type
(S_Typ
) or else S_Typ
= Any_Type
then
2945 Is_Unconstrained_Subscr_Ref
:=
2946 Is_Subscr_Ref
and then not Is_Constrained
(Arr_Typ
);
2948 -- Special checks for floating-point type
2950 if Is_Floating_Point_Type
(S_Typ
) then
2952 -- Always do a range check if the source type includes infinities and
2953 -- the target type does not include infinities. We do not do this if
2954 -- range checks are killed.
2955 -- If the expression is a literal and the bounds of the type are
2956 -- static constants it may be possible to optimize the check.
2958 if Has_Infinities
(S_Typ
)
2959 and then not Has_Infinities
(Target_Typ
)
2961 -- If the expression is a literal and the bounds of the type are
2962 -- static constants it may be possible to optimize the check.
2964 if Nkind
(Expr
) = N_Real_Literal
then
2966 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
2967 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
2970 if Compile_Time_Known_Value
(Tlo
)
2971 and then Compile_Time_Known_Value
(Thi
)
2972 and then Expr_Value_R
(Expr
) >= Expr_Value_R
(Tlo
)
2973 and then Expr_Value_R
(Expr
) <= Expr_Value_R
(Thi
)
2977 Enable_Range_Check
(Expr
);
2982 Enable_Range_Check
(Expr
);
2987 -- Return if we know expression is definitely in the range of the target
2988 -- type as determined by Determine_Range. Right now we only do this for
2989 -- discrete types, and not fixed-point or floating-point types.
2991 -- The additional less-precise tests below catch these cases
2993 -- In GNATprove_Mode, also deal with the case of a conversion from
2994 -- floating-point to integer. It is only possible because analysis
2995 -- in GNATprove rules out the possibility of a NaN or infinite value.
2997 -- Note: skip this if we are given a source_typ, since the point of
2998 -- supplying a Source_Typ is to stop us looking at the expression.
2999 -- We could sharpen this test to be out parameters only ???
3001 if Is_Discrete_Type
(Target_Typ
)
3002 and then (Is_Discrete_Type
(Etype
(Expr
))
3003 or else (GNATprove_Mode
3004 and then Is_Floating_Point_Type
(Etype
(Expr
))))
3005 and then not Is_Unconstrained_Subscr_Ref
3006 and then No
(Source_Typ
)
3009 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Typ
);
3010 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Typ
);
3013 if Compile_Time_Known_Value
(Tlo
)
3014 and then Compile_Time_Known_Value
(Thi
)
3017 OK
: Boolean := False; -- initialize to prevent warning
3018 Hiv
: constant Uint
:= Expr_Value
(Thi
);
3019 Lov
: constant Uint
:= Expr_Value
(Tlo
);
3020 Hi
: Uint
:= No_Uint
;
3021 Lo
: Uint
:= No_Uint
;
3024 -- If range is null, we for sure have a constraint error (we
3025 -- don't even need to look at the value involved, since all
3026 -- possible values will raise CE).
3030 -- When SPARK_Mode is On, force a warning instead of
3031 -- an error in that case, as this likely corresponds
3032 -- to deactivated code.
3034 Bad_Value
(Warn
=> SPARK_Mode
= On
);
3036 -- In GNATprove mode, we enable the range check so that
3037 -- GNATprove will issue a message if it cannot be proved.
3039 if GNATprove_Mode
then
3040 Enable_Range_Check
(Expr
);
3046 -- Otherwise determine range of value
3048 if Is_Discrete_Type
(Etype
(Expr
)) then
3050 (Expr
, OK
, Lo
, Hi
, Assume_Valid
=> True);
3052 -- When converting a float to an integer type, determine the
3053 -- range in real first, and then convert the bounds using
3054 -- UR_To_Uint which correctly rounds away from zero when
3055 -- half way between two integers, as required by normal
3056 -- Ada 95 rounding semantics. It is only possible because
3057 -- analysis in GNATprove rules out the possibility of a NaN
3058 -- or infinite value.
3060 elsif GNATprove_Mode
3061 and then Is_Floating_Point_Type
(Etype
(Expr
))
3069 (Expr
, OK
, Lor
, Hir
, Assume_Valid
=> True);
3072 Lo
:= UR_To_Uint
(Lor
);
3073 Hi
:= UR_To_Uint
(Hir
);
3080 -- If definitely in range, all OK
3082 if Lo
>= Lov
and then Hi
<= Hiv
then
3085 -- If definitely not in range, warn
3087 elsif Lov
> Hi
or else Hiv
< Lo
then
3089 -- Ignore out of range values for System.Priority in
3090 -- CodePeer mode since the actual target compiler may
3091 -- provide a wider range.
3093 if not CodePeer_Mode
3094 or else Target_Typ
/= RTE
(RE_Priority
)
3101 -- Otherwise we don't know
3113 Is_Floating_Point_Type
(S_Typ
)
3114 or else (Is_Fixed_Point_Type
(S_Typ
) and then not Fixed_Int
);
3116 -- Check if we can determine at compile time whether Expr is in the
3117 -- range of the target type. Note that if S_Typ is within the bounds
3118 -- of Target_Typ then this must be the case. This check is meaningful
3119 -- only if this is not a conversion between integer and real types.
3121 if not Is_Unconstrained_Subscr_Ref
3122 and then Is_Discrete_Type
(S_Typ
) = Is_Discrete_Type
(Target_Typ
)
3124 (In_Subrange_Of
(S_Typ
, Target_Typ
, Fixed_Int
)
3126 -- Also check if the expression itself is in the range of the
3127 -- target type if it is a known at compile time value. We skip
3128 -- this test if S_Typ is set since for OUT and IN OUT parameters
3129 -- the Expr itself is not relevant to the checking.
3133 and then Is_In_Range
(Expr
, Target_Typ
,
3134 Assume_Valid
=> True,
3135 Fixed_Int
=> Fixed_Int
,
3136 Int_Real
=> Int_Real
)))
3140 elsif Is_Out_Of_Range
(Expr
, Target_Typ
,
3141 Assume_Valid
=> True,
3142 Fixed_Int
=> Fixed_Int
,
3143 Int_Real
=> Int_Real
)
3148 -- Floating-point case
3149 -- In the floating-point case, we only do range checks if the type is
3150 -- constrained. We definitely do NOT want range checks for unconstrained
3151 -- types, since we want to have infinities, except when
3152 -- Check_Float_Overflow is set.
3154 elsif Is_Floating_Point_Type
(S_Typ
) then
3155 if Is_Constrained
(S_Typ
) or else Check_Float_Overflow
then
3156 Enable_Range_Check
(Expr
);
3159 -- For all other cases we enable a range check unconditionally
3162 Enable_Range_Check
(Expr
);
3165 end Apply_Scalar_Range_Check
;
3167 ----------------------------------
3168 -- Apply_Selected_Length_Checks --
3169 ----------------------------------
3171 procedure Apply_Selected_Length_Checks
3173 Target_Typ
: Entity_Id
;
3174 Source_Typ
: Entity_Id
;
3175 Do_Static
: Boolean)
3177 Checks_On
: constant Boolean :=
3178 not Index_Checks_Suppressed
(Target_Typ
)
3180 not Length_Checks_Suppressed
(Target_Typ
);
3182 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
3186 R_Result
: Check_Result
;
3189 -- Only apply checks when generating code
3191 -- Note: this means that we lose some useful warnings if the expander
3194 if not Expander_Active
then
3199 Selected_Length_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
3201 for J
in 1 .. 2 loop
3202 R_Cno
:= R_Result
(J
);
3203 exit when No
(R_Cno
);
3205 -- A length check may mention an Itype which is attached to a
3206 -- subsequent node. At the top level in a package this can cause
3207 -- an order-of-elaboration problem, so we make sure that the itype
3208 -- is referenced now.
3210 if Ekind
(Current_Scope
) = E_Package
3211 and then Is_Compilation_Unit
(Current_Scope
)
3213 Ensure_Defined
(Target_Typ
, Ck_Node
);
3215 if Present
(Source_Typ
) then
3216 Ensure_Defined
(Source_Typ
, Ck_Node
);
3218 elsif Is_Itype
(Etype
(Ck_Node
)) then
3219 Ensure_Defined
(Etype
(Ck_Node
), Ck_Node
);
3223 -- If the item is a conditional raise of constraint error, then have
3224 -- a look at what check is being performed and ???
3226 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
3227 and then Present
(Condition
(R_Cno
))
3229 Cond
:= Condition
(R_Cno
);
3231 -- Case where node does not now have a dynamic check
3233 if not Has_Dynamic_Length_Check
(Ck_Node
) then
3235 -- If checks are on, just insert the check
3238 Insert_Action
(Ck_Node
, R_Cno
);
3240 if not Do_Static
then
3241 Set_Has_Dynamic_Length_Check
(Ck_Node
);
3244 -- If checks are off, then analyze the length check after
3245 -- temporarily attaching it to the tree in case the relevant
3246 -- condition can be evaluated at compile time. We still want a
3247 -- compile time warning in this case.
3250 Set_Parent
(R_Cno
, Ck_Node
);
3255 -- Output a warning if the condition is known to be True
3257 if Is_Entity_Name
(Cond
)
3258 and then Entity
(Cond
) = Standard_True
3260 Apply_Compile_Time_Constraint_Error
3261 (Ck_Node
, "wrong length for array of}??",
3262 CE_Length_Check_Failed
,
3266 -- If we were only doing a static check, or if checks are not
3267 -- on, then we want to delete the check, since it is not needed.
3268 -- We do this by replacing the if statement by a null statement
3270 elsif Do_Static
or else not Checks_On
then
3271 Remove_Warning_Messages
(R_Cno
);
3272 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
3276 Install_Static_Check
(R_Cno
, Loc
);
3279 end Apply_Selected_Length_Checks
;
3281 ---------------------------------
3282 -- Apply_Selected_Range_Checks --
3283 ---------------------------------
3285 procedure Apply_Selected_Range_Checks
3287 Target_Typ
: Entity_Id
;
3288 Source_Typ
: Entity_Id
;
3289 Do_Static
: Boolean)
3291 Checks_On
: constant Boolean :=
3292 not Index_Checks_Suppressed
(Target_Typ
)
3294 not Range_Checks_Suppressed
(Target_Typ
);
3296 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
3300 R_Result
: Check_Result
;
3303 -- Only apply checks when generating code. In GNATprove mode, we do not
3304 -- apply the checks, but we still call Selected_Range_Checks to possibly
3305 -- issue errors on SPARK code when a run-time error can be detected at
3308 if not GNATprove_Mode
then
3309 if not Expander_Active
or not Checks_On
then
3315 Selected_Range_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Empty
);
3317 if GNATprove_Mode
then
3321 for J
in 1 .. 2 loop
3322 R_Cno
:= R_Result
(J
);
3323 exit when No
(R_Cno
);
3325 -- The range check requires runtime evaluation. Depending on what its
3326 -- triggering condition is, the check may be converted into a compile
3327 -- time constraint check.
3329 if Nkind
(R_Cno
) = N_Raise_Constraint_Error
3330 and then Present
(Condition
(R_Cno
))
3332 Cond
:= Condition
(R_Cno
);
3334 -- Insert the range check before the related context. Note that
3335 -- this action analyses the triggering condition.
3337 Insert_Action
(Ck_Node
, R_Cno
);
3339 -- This old code doesn't make sense, why is the context flagged as
3340 -- requiring dynamic range checks now in the middle of generating
3343 if not Do_Static
then
3344 Set_Has_Dynamic_Range_Check
(Ck_Node
);
3347 -- The triggering condition evaluates to True, the range check
3348 -- can be converted into a compile time constraint check.
3350 if Is_Entity_Name
(Cond
)
3351 and then Entity
(Cond
) = Standard_True
3353 -- Since an N_Range is technically not an expression, we have
3354 -- to set one of the bounds to C_E and then just flag the
3355 -- N_Range. The warning message will point to the lower bound
3356 -- and complain about a range, which seems OK.
3358 if Nkind
(Ck_Node
) = N_Range
then
3359 Apply_Compile_Time_Constraint_Error
3360 (Low_Bound
(Ck_Node
),
3361 "static range out of bounds of}??",
3362 CE_Range_Check_Failed
,
3366 Set_Raises_Constraint_Error
(Ck_Node
);
3369 Apply_Compile_Time_Constraint_Error
3371 "static value out of range of}??",
3372 CE_Range_Check_Failed
,
3377 -- If we were only doing a static check, or if checks are not
3378 -- on, then we want to delete the check, since it is not needed.
3379 -- We do this by replacing the if statement by a null statement
3381 elsif Do_Static
then
3382 Remove_Warning_Messages
(R_Cno
);
3383 Rewrite
(R_Cno
, Make_Null_Statement
(Loc
));
3386 -- The range check raises Constraint_Error explicitly
3389 Install_Static_Check
(R_Cno
, Loc
);
3392 end Apply_Selected_Range_Checks
;
3394 -------------------------------
3395 -- Apply_Static_Length_Check --
3396 -------------------------------
3398 procedure Apply_Static_Length_Check
3400 Target_Typ
: Entity_Id
;
3401 Source_Typ
: Entity_Id
:= Empty
)
3404 Apply_Selected_Length_Checks
3405 (Expr
, Target_Typ
, Source_Typ
, Do_Static
=> True);
3406 end Apply_Static_Length_Check
;
3408 -------------------------------------
3409 -- Apply_Subscript_Validity_Checks --
3410 -------------------------------------
3412 procedure Apply_Subscript_Validity_Checks
(Expr
: Node_Id
) is
3416 pragma Assert
(Nkind
(Expr
) = N_Indexed_Component
);
3418 -- Loop through subscripts
3420 Sub
:= First
(Expressions
(Expr
));
3421 while Present
(Sub
) loop
3423 -- Check one subscript. Note that we do not worry about enumeration
3424 -- type with holes, since we will convert the value to a Pos value
3425 -- for the subscript, and that convert will do the necessary validity
3428 Ensure_Valid
(Sub
, Holes_OK
=> True);
3430 -- Move to next subscript
3434 end Apply_Subscript_Validity_Checks
;
3436 ----------------------------------
3437 -- Apply_Type_Conversion_Checks --
3438 ----------------------------------
3440 procedure Apply_Type_Conversion_Checks
(N
: Node_Id
) is
3441 Target_Type
: constant Entity_Id
:= Etype
(N
);
3442 Target_Base
: constant Entity_Id
:= Base_Type
(Target_Type
);
3443 Expr
: constant Node_Id
:= Expression
(N
);
3445 Expr_Type
: constant Entity_Id
:= Underlying_Type
(Etype
(Expr
));
3446 -- Note: if Etype (Expr) is a private type without discriminants, its
3447 -- full view might have discriminants with defaults, so we need the
3448 -- full view here to retrieve the constraints.
3451 if Inside_A_Generic
then
3454 -- Skip these checks if serious errors detected, there are some nasty
3455 -- situations of incomplete trees that blow things up.
3457 elsif Serious_Errors_Detected
> 0 then
3460 -- Never generate discriminant checks for Unchecked_Union types
3462 elsif Present
(Expr_Type
)
3463 and then Is_Unchecked_Union
(Expr_Type
)
3467 -- Scalar type conversions of the form Target_Type (Expr) require a
3468 -- range check if we cannot be sure that Expr is in the base type of
3469 -- Target_Typ and also that Expr is in the range of Target_Typ. These
3470 -- are not quite the same condition from an implementation point of
3471 -- view, but clearly the second includes the first.
3473 elsif Is_Scalar_Type
(Target_Type
) then
3475 Conv_OK
: constant Boolean := Conversion_OK
(N
);
3476 -- If the Conversion_OK flag on the type conversion is set and no
3477 -- floating-point type is involved in the type conversion then
3478 -- fixed-point values must be read as integral values.
3480 Float_To_Int
: constant Boolean :=
3481 Is_Floating_Point_Type
(Expr_Type
)
3482 and then Is_Integer_Type
(Target_Type
);
3485 if not Overflow_Checks_Suppressed
(Target_Base
)
3486 and then not Overflow_Checks_Suppressed
(Target_Type
)
3488 In_Subrange_Of
(Expr_Type
, Target_Base
, Fixed_Int
=> Conv_OK
)
3489 and then not Float_To_Int
3491 -- A small optimization: the attribute 'Pos applied to an
3492 -- enumeration type has a known range, even though its type is
3493 -- Universal_Integer. So in numeric conversions it is usually
3494 -- within range of the target integer type. Use the static
3495 -- bounds of the base types to check. Disable this optimization
3496 -- in case of a generic formal discrete type, because we don't
3497 -- necessarily know the upper bound yet.
3499 if Nkind
(Expr
) = N_Attribute_Reference
3500 and then Attribute_Name
(Expr
) = Name_Pos
3501 and then Is_Enumeration_Type
(Etype
(Prefix
(Expr
)))
3502 and then not Is_Generic_Type
(Etype
(Prefix
(Expr
)))
3503 and then Is_Integer_Type
(Target_Type
)
3506 Enum_T
: constant Entity_Id
:=
3507 Root_Type
(Etype
(Prefix
(Expr
)));
3508 Int_T
: constant Entity_Id
:= Base_Type
(Target_Type
);
3509 Last_I
: constant Uint
:=
3510 Intval
(High_Bound
(Scalar_Range
(Int_T
)));
3514 -- Character types have no explicit literals, so we use
3515 -- the known number of characters in the type.
3517 if Root_Type
(Enum_T
) = Standard_Character
then
3518 Last_E
:= UI_From_Int
(255);
3520 elsif Enum_T
= Standard_Wide_Character
3521 or else Enum_T
= Standard_Wide_Wide_Character
3523 Last_E
:= UI_From_Int
(65535);
3528 (Entity
(High_Bound
(Scalar_Range
(Enum_T
))));
3531 if Last_E
<= Last_I
then
3535 Activate_Overflow_Check
(N
);
3540 Activate_Overflow_Check
(N
);
3544 if not Range_Checks_Suppressed
(Target_Type
)
3545 and then not Range_Checks_Suppressed
(Expr_Type
)
3548 and then not GNATprove_Mode
3550 Apply_Float_Conversion_Check
(Expr
, Target_Type
);
3553 -- Conversions involving fixed-point types are expanded
3554 -- separately, and do not need a Range_Check flag, except
3555 -- in SPARK_Mode, where the explicit constraint check will
3556 -- not be generated.
3559 or else not Is_Fixed_Point_Type
(Expr_Type
)
3561 Apply_Scalar_Range_Check
3562 (Expr
, Target_Type
, Fixed_Int
=> Conv_OK
);
3565 Set_Do_Range_Check
(Expression
(N
), False);
3568 -- If the target type has predicates, we need to indicate
3569 -- the need for a check, even if Determine_Range finds that
3570 -- the value is within bounds. This may be the case e.g for
3571 -- a division with a constant denominator.
3573 if Has_Predicates
(Target_Type
) then
3574 Enable_Range_Check
(Expr
);
3580 elsif Comes_From_Source
(N
)
3581 and then not Discriminant_Checks_Suppressed
(Target_Type
)
3582 and then Is_Record_Type
(Target_Type
)
3583 and then Is_Derived_Type
(Target_Type
)
3584 and then not Is_Tagged_Type
(Target_Type
)
3585 and then not Is_Constrained
(Target_Type
)
3586 and then Present
(Stored_Constraint
(Target_Type
))
3588 -- An unconstrained derived type may have inherited discriminant.
3589 -- Build an actual discriminant constraint list using the stored
3590 -- constraint, to verify that the expression of the parent type
3591 -- satisfies the constraints imposed by the (unconstrained) derived
3592 -- type. This applies to value conversions, not to view conversions
3596 Loc
: constant Source_Ptr
:= Sloc
(N
);
3598 Constraint
: Elmt_Id
;
3599 Discr_Value
: Node_Id
;
3602 New_Constraints
: constant Elist_Id
:= New_Elmt_List
;
3603 Old_Constraints
: constant Elist_Id
:=
3604 Discriminant_Constraint
(Expr_Type
);
3607 Constraint
:= First_Elmt
(Stored_Constraint
(Target_Type
));
3608 while Present
(Constraint
) loop
3609 Discr_Value
:= Node
(Constraint
);
3611 if Is_Entity_Name
(Discr_Value
)
3612 and then Ekind
(Entity
(Discr_Value
)) = E_Discriminant
3614 Discr
:= Corresponding_Discriminant
(Entity
(Discr_Value
));
3617 and then Scope
(Discr
) = Base_Type
(Expr_Type
)
3619 -- Parent is constrained by new discriminant. Obtain
3620 -- Value of original discriminant in expression. If the
3621 -- new discriminant has been used to constrain more than
3622 -- one of the stored discriminants, this will provide the
3623 -- required consistency check.
3626 (Make_Selected_Component
(Loc
,
3628 Duplicate_Subexpr_No_Checks
3629 (Expr
, Name_Req
=> True),
3631 Make_Identifier
(Loc
, Chars
(Discr
))),
3635 -- Discriminant of more remote ancestor ???
3640 -- Derived type definition has an explicit value for this
3641 -- stored discriminant.
3645 (Duplicate_Subexpr_No_Checks
(Discr_Value
),
3649 Next_Elmt
(Constraint
);
3652 -- Use the unconstrained expression type to retrieve the
3653 -- discriminants of the parent, and apply momentarily the
3654 -- discriminant constraint synthesized above.
3656 Set_Discriminant_Constraint
(Expr_Type
, New_Constraints
);
3657 Cond
:= Build_Discriminant_Checks
(Expr
, Expr_Type
);
3658 Set_Discriminant_Constraint
(Expr_Type
, Old_Constraints
);
3661 Make_Raise_Constraint_Error
(Loc
,
3663 Reason
=> CE_Discriminant_Check_Failed
));
3666 -- For arrays, checks are set now, but conversions are applied during
3667 -- expansion, to take into accounts changes of representation. The
3668 -- checks become range checks on the base type or length checks on the
3669 -- subtype, depending on whether the target type is unconstrained or
3670 -- constrained. Note that the range check is put on the expression of a
3671 -- type conversion, while the length check is put on the type conversion
3674 elsif Is_Array_Type
(Target_Type
) then
3675 if Is_Constrained
(Target_Type
) then
3676 Set_Do_Length_Check
(N
);
3678 Set_Do_Range_Check
(Expr
);
3681 end Apply_Type_Conversion_Checks
;
3683 ----------------------------------------------
3684 -- Apply_Universal_Integer_Attribute_Checks --
3685 ----------------------------------------------
3687 procedure Apply_Universal_Integer_Attribute_Checks
(N
: Node_Id
) is
3688 Loc
: constant Source_Ptr
:= Sloc
(N
);
3689 Typ
: constant Entity_Id
:= Etype
(N
);
3692 if Inside_A_Generic
then
3695 -- Nothing to do if checks are suppressed
3697 elsif Range_Checks_Suppressed
(Typ
)
3698 and then Overflow_Checks_Suppressed
(Typ
)
3702 -- Nothing to do if the attribute does not come from source. The
3703 -- internal attributes we generate of this type do not need checks,
3704 -- and furthermore the attempt to check them causes some circular
3705 -- elaboration orders when dealing with packed types.
3707 elsif not Comes_From_Source
(N
) then
3710 -- If the prefix is a selected component that depends on a discriminant
3711 -- the check may improperly expose a discriminant instead of using
3712 -- the bounds of the object itself. Set the type of the attribute to
3713 -- the base type of the context, so that a check will be imposed when
3714 -- needed (e.g. if the node appears as an index).
3716 elsif Nkind
(Prefix
(N
)) = N_Selected_Component
3717 and then Ekind
(Typ
) = E_Signed_Integer_Subtype
3718 and then Depends_On_Discriminant
(Scalar_Range
(Typ
))
3720 Set_Etype
(N
, Base_Type
(Typ
));
3722 -- Otherwise, replace the attribute node with a type conversion node
3723 -- whose expression is the attribute, retyped to universal integer, and
3724 -- whose subtype mark is the target type. The call to analyze this
3725 -- conversion will set range and overflow checks as required for proper
3726 -- detection of an out of range value.
3729 Set_Etype
(N
, Universal_Integer
);
3730 Set_Analyzed
(N
, True);
3733 Make_Type_Conversion
(Loc
,
3734 Subtype_Mark
=> New_Occurrence_Of
(Typ
, Loc
),
3735 Expression
=> Relocate_Node
(N
)));
3737 Analyze_And_Resolve
(N
, Typ
);
3740 end Apply_Universal_Integer_Attribute_Checks
;
3742 -------------------------------------
3743 -- Atomic_Synchronization_Disabled --
3744 -------------------------------------
3746 -- Note: internally Disable/Enable_Atomic_Synchronization is implemented
3747 -- using a bogus check called Atomic_Synchronization. This is to make it
3748 -- more convenient to get exactly the same semantics as [Un]Suppress.
3750 function Atomic_Synchronization_Disabled
(E
: Entity_Id
) return Boolean is
3752 -- If debug flag d.e is set, always return False, i.e. all atomic sync
3753 -- looks enabled, since it is never disabled.
3755 if Debug_Flag_Dot_E
then
3758 -- If debug flag d.d is set then always return True, i.e. all atomic
3759 -- sync looks disabled, since it always tests True.
3761 elsif Debug_Flag_Dot_D
then
3764 -- If entity present, then check result for that entity
3766 elsif Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
3767 return Is_Check_Suppressed
(E
, Atomic_Synchronization
);
3769 -- Otherwise result depends on current scope setting
3772 return Scope_Suppress
.Suppress
(Atomic_Synchronization
);
3774 end Atomic_Synchronization_Disabled
;
3776 -------------------------------
3777 -- Build_Discriminant_Checks --
3778 -------------------------------
3780 function Build_Discriminant_Checks
3782 T_Typ
: Entity_Id
) return Node_Id
3784 Loc
: constant Source_Ptr
:= Sloc
(N
);
3787 Disc_Ent
: Entity_Id
;
3791 function Aggregate_Discriminant_Val
(Disc
: Entity_Id
) return Node_Id
;
3793 --------------------------------
3794 -- Aggregate_Discriminant_Val --
3795 --------------------------------
3797 function Aggregate_Discriminant_Val
(Disc
: Entity_Id
) return Node_Id
is
3801 -- The aggregate has been normalized with named associations. We use
3802 -- the Chars field to locate the discriminant to take into account
3803 -- discriminants in derived types, which carry the same name as those
3806 Assoc
:= First
(Component_Associations
(N
));
3807 while Present
(Assoc
) loop
3808 if Chars
(First
(Choices
(Assoc
))) = Chars
(Disc
) then
3809 return Expression
(Assoc
);
3815 -- Discriminant must have been found in the loop above
3817 raise Program_Error
;
3818 end Aggregate_Discriminant_Val
;
3820 -- Start of processing for Build_Discriminant_Checks
3823 -- Loop through discriminants evolving the condition
3826 Disc
:= First_Elmt
(Discriminant_Constraint
(T_Typ
));
3828 -- For a fully private type, use the discriminants of the parent type
3830 if Is_Private_Type
(T_Typ
)
3831 and then No
(Full_View
(T_Typ
))
3833 Disc_Ent
:= First_Discriminant
(Etype
(Base_Type
(T_Typ
)));
3835 Disc_Ent
:= First_Discriminant
(T_Typ
);
3838 while Present
(Disc
) loop
3839 Dval
:= Node
(Disc
);
3841 if Nkind
(Dval
) = N_Identifier
3842 and then Ekind
(Entity
(Dval
)) = E_Discriminant
3844 Dval
:= New_Occurrence_Of
(Discriminal
(Entity
(Dval
)), Loc
);
3846 Dval
:= Duplicate_Subexpr_No_Checks
(Dval
);
3849 -- If we have an Unchecked_Union node, we can infer the discriminants
3852 if Is_Unchecked_Union
(Base_Type
(T_Typ
)) then
3854 Get_Discriminant_Value
(
3855 First_Discriminant
(T_Typ
),
3857 Stored_Constraint
(T_Typ
)));
3859 elsif Nkind
(N
) = N_Aggregate
then
3861 Duplicate_Subexpr_No_Checks
3862 (Aggregate_Discriminant_Val
(Disc_Ent
));
3866 Make_Selected_Component
(Loc
,
3868 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
3869 Selector_Name
=> Make_Identifier
(Loc
, Chars
(Disc_Ent
)));
3871 Set_Is_In_Discriminant_Check
(Dref
);
3874 Evolve_Or_Else
(Cond
,
3877 Right_Opnd
=> Dval
));
3880 Next_Discriminant
(Disc_Ent
);
3884 end Build_Discriminant_Checks
;
3890 function Check_Needed
(Nod
: Node_Id
; Check
: Check_Type
) return Boolean is
3897 function Left_Expression
(Op
: Node_Id
) return Node_Id
;
3898 -- Return the relevant expression from the left operand of the given
3899 -- short circuit form: this is LO itself, except if LO is a qualified
3900 -- expression, a type conversion, or an expression with actions, in
3901 -- which case this is Left_Expression (Expression (LO)).
3903 ---------------------
3904 -- Left_Expression --
3905 ---------------------
3907 function Left_Expression
(Op
: Node_Id
) return Node_Id
is
3908 LE
: Node_Id
:= Left_Opnd
(Op
);
3910 while Nkind_In
(LE
, N_Qualified_Expression
,
3912 N_Expression_With_Actions
)
3914 LE
:= Expression
(LE
);
3918 end Left_Expression
;
3920 -- Start of processing for Check_Needed
3923 -- Always check if not simple entity
3925 if Nkind
(Nod
) not in N_Has_Entity
3926 or else not Comes_From_Source
(Nod
)
3931 -- Look up tree for short circuit
3938 -- Done if out of subexpression (note that we allow generated stuff
3939 -- such as itype declarations in this context, to keep the loop going
3940 -- since we may well have generated such stuff in complex situations.
3941 -- Also done if no parent (probably an error condition, but no point
3942 -- in behaving nasty if we find it).
3945 or else (K
not in N_Subexpr
and then Comes_From_Source
(P
))
3949 -- Or/Or Else case, where test is part of the right operand, or is
3950 -- part of one of the actions associated with the right operand, and
3951 -- the left operand is an equality test.
3953 elsif K
= N_Op_Or
then
3954 exit when N
= Right_Opnd
(P
)
3955 and then Nkind
(Left_Expression
(P
)) = N_Op_Eq
;
3957 elsif K
= N_Or_Else
then
3958 exit when (N
= Right_Opnd
(P
)
3961 and then List_Containing
(N
) = Actions
(P
)))
3962 and then Nkind
(Left_Expression
(P
)) = N_Op_Eq
;
3964 -- Similar test for the And/And then case, where the left operand
3965 -- is an inequality test.
3967 elsif K
= N_Op_And
then
3968 exit when N
= Right_Opnd
(P
)
3969 and then Nkind
(Left_Expression
(P
)) = N_Op_Ne
;
3971 elsif K
= N_And_Then
then
3972 exit when (N
= Right_Opnd
(P
)
3975 and then List_Containing
(N
) = Actions
(P
)))
3976 and then Nkind
(Left_Expression
(P
)) = N_Op_Ne
;
3982 -- If we fall through the loop, then we have a conditional with an
3983 -- appropriate test as its left operand, so look further.
3985 L
:= Left_Expression
(P
);
3987 -- L is an "=" or "/=" operator: extract its operands
3989 R
:= Right_Opnd
(L
);
3992 -- Left operand of test must match original variable
3994 if Nkind
(L
) not in N_Has_Entity
or else Entity
(L
) /= Entity
(Nod
) then
3998 -- Right operand of test must be key value (zero or null)
4001 when Access_Check
=>
4002 if not Known_Null
(R
) then
4006 when Division_Check
=>
4007 if not Compile_Time_Known_Value
(R
)
4008 or else Expr_Value
(R
) /= Uint_0
4014 raise Program_Error
;
4017 -- Here we have the optimizable case, warn if not short-circuited
4019 if K
= N_Op_And
or else K
= N_Op_Or
then
4020 Error_Msg_Warn
:= SPARK_Mode
/= On
;
4023 when Access_Check
=>
4024 if GNATprove_Mode
then
4026 ("Constraint_Error might have been raised (access check)",
4030 ("Constraint_Error may be raised (access check)??",
4034 when Division_Check
=>
4035 if GNATprove_Mode
then
4037 ("Constraint_Error might have been raised (zero divide)",
4041 ("Constraint_Error may be raised (zero divide)??",
4046 raise Program_Error
;
4049 if K
= N_Op_And
then
4050 Error_Msg_N
-- CODEFIX
4051 ("use `AND THEN` instead of AND??", P
);
4053 Error_Msg_N
-- CODEFIX
4054 ("use `OR ELSE` instead of OR??", P
);
4057 -- If not short-circuited, we need the check
4061 -- If short-circuited, we can omit the check
4068 -----------------------------------
4069 -- Check_Valid_Lvalue_Subscripts --
4070 -----------------------------------
4072 procedure Check_Valid_Lvalue_Subscripts
(Expr
: Node_Id
) is
4074 -- Skip this if range checks are suppressed
4076 if Range_Checks_Suppressed
(Etype
(Expr
)) then
4079 -- Only do this check for expressions that come from source. We assume
4080 -- that expander generated assignments explicitly include any necessary
4081 -- checks. Note that this is not just an optimization, it avoids
4082 -- infinite recursions.
4084 elsif not Comes_From_Source
(Expr
) then
4087 -- For a selected component, check the prefix
4089 elsif Nkind
(Expr
) = N_Selected_Component
then
4090 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
4093 -- Case of indexed component
4095 elsif Nkind
(Expr
) = N_Indexed_Component
then
4096 Apply_Subscript_Validity_Checks
(Expr
);
4098 -- Prefix may itself be or contain an indexed component, and these
4099 -- subscripts need checking as well.
4101 Check_Valid_Lvalue_Subscripts
(Prefix
(Expr
));
4103 end Check_Valid_Lvalue_Subscripts
;
4105 ----------------------------------
4106 -- Null_Exclusion_Static_Checks --
4107 ----------------------------------
4109 procedure Null_Exclusion_Static_Checks
4111 Comp
: Node_Id
:= Empty
;
4112 Array_Comp
: Boolean := False)
4114 Has_Null
: constant Boolean := Has_Null_Exclusion
(N
);
4115 Kind
: constant Node_Kind
:= Nkind
(N
);
4116 Error_Nod
: Node_Id
;
4122 (Nkind_In
(Kind
, N_Component_Declaration
,
4123 N_Discriminant_Specification
,
4124 N_Function_Specification
,
4125 N_Object_Declaration
,
4126 N_Parameter_Specification
));
4128 if Kind
= N_Function_Specification
then
4129 Typ
:= Etype
(Defining_Entity
(N
));
4131 Typ
:= Etype
(Defining_Identifier
(N
));
4135 when N_Component_Declaration
=>
4136 if Present
(Access_Definition
(Component_Definition
(N
))) then
4137 Error_Nod
:= Component_Definition
(N
);
4139 Error_Nod
:= Subtype_Indication
(Component_Definition
(N
));
4142 when N_Discriminant_Specification
=>
4143 Error_Nod
:= Discriminant_Type
(N
);
4145 when N_Function_Specification
=>
4146 Error_Nod
:= Result_Definition
(N
);
4148 when N_Object_Declaration
=>
4149 Error_Nod
:= Object_Definition
(N
);
4151 when N_Parameter_Specification
=>
4152 Error_Nod
:= Parameter_Type
(N
);
4155 raise Program_Error
;
4160 -- Enforce legality rule 3.10 (13): A null exclusion can only be
4161 -- applied to an access [sub]type.
4163 if not Is_Access_Type
(Typ
) then
4165 ("`NOT NULL` allowed only for an access type", Error_Nod
);
4167 -- Enforce legality rule RM 3.10(14/1): A null exclusion can only
4168 -- be applied to a [sub]type that does not exclude null already.
4170 elsif Can_Never_Be_Null
(Typ
) and then Comes_From_Source
(Typ
) then
4172 ("`NOT NULL` not allowed (& already excludes null)",
4177 -- Check that null-excluding objects are always initialized, except for
4178 -- deferred constants, for which the expression will appear in the full
4181 if Kind
= N_Object_Declaration
4182 and then No
(Expression
(N
))
4183 and then not Constant_Present
(N
)
4184 and then not No_Initialization
(N
)
4186 if Present
(Comp
) then
4188 -- Specialize the warning message to indicate that we are dealing
4189 -- with an uninitialized composite object that has a defaulted
4190 -- null-excluding component.
4192 Error_Msg_Name_1
:= Chars
(Defining_Identifier
(Comp
));
4193 Error_Msg_Name_2
:= Chars
(Defining_Identifier
(N
));
4196 (Compile_Time_Constraint_Error
4199 "(Ada 2005) null-excluding component % of object % must "
4200 & "be initialized??",
4201 Ent
=> Defining_Identifier
(Comp
)));
4203 -- This is a case of an array with null-excluding components, so
4204 -- indicate that in the warning.
4206 elsif Array_Comp
then
4208 (Compile_Time_Constraint_Error
4211 "(Ada 2005) null-excluding array components must "
4212 & "be initialized??",
4213 Ent
=> Defining_Identifier
(N
)));
4215 -- Normal case of object of a null-excluding access type
4218 -- Add an expression that assigns null. This node is needed by
4219 -- Apply_Compile_Time_Constraint_Error, which will replace this
4220 -- with a Constraint_Error node.
4222 Set_Expression
(N
, Make_Null
(Sloc
(N
)));
4223 Set_Etype
(Expression
(N
), Etype
(Defining_Identifier
(N
)));
4225 Apply_Compile_Time_Constraint_Error
4226 (N
=> Expression
(N
),
4228 "(Ada 2005) null-excluding objects must be initialized??",
4229 Reason
=> CE_Null_Not_Allowed
);
4233 -- Check that a null-excluding component, formal or object is not being
4234 -- assigned a null value. Otherwise generate a warning message and
4235 -- replace Expression (N) by an N_Constraint_Error node.
4237 if Kind
/= N_Function_Specification
then
4238 Expr
:= Expression
(N
);
4240 if Present
(Expr
) and then Known_Null
(Expr
) then
4242 when N_Component_Declaration
4243 | N_Discriminant_Specification
4245 Apply_Compile_Time_Constraint_Error
4248 "(Ada 2005) null not allowed in null-excluding "
4250 Reason
=> CE_Null_Not_Allowed
);
4252 when N_Object_Declaration
=>
4253 Apply_Compile_Time_Constraint_Error
4256 "(Ada 2005) null not allowed in null-excluding "
4258 Reason
=> CE_Null_Not_Allowed
);
4260 when N_Parameter_Specification
=>
4261 Apply_Compile_Time_Constraint_Error
4264 "(Ada 2005) null not allowed in null-excluding "
4266 Reason
=> CE_Null_Not_Allowed
);
4273 end Null_Exclusion_Static_Checks
;
4275 ----------------------------------
4276 -- Conditional_Statements_Begin --
4277 ----------------------------------
4279 procedure Conditional_Statements_Begin
is
4281 Saved_Checks_TOS
:= Saved_Checks_TOS
+ 1;
4283 -- If stack overflows, kill all checks, that way we know to simply reset
4284 -- the number of saved checks to zero on return. This should never occur
4287 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
4290 -- In the normal case, we just make a new stack entry saving the current
4291 -- number of saved checks for a later restore.
4294 Saved_Checks_Stack
(Saved_Checks_TOS
) := Num_Saved_Checks
;
4296 if Debug_Flag_CC
then
4297 w
("Conditional_Statements_Begin: Num_Saved_Checks = ",
4301 end Conditional_Statements_Begin
;
4303 --------------------------------
4304 -- Conditional_Statements_End --
4305 --------------------------------
4307 procedure Conditional_Statements_End
is
4309 pragma Assert
(Saved_Checks_TOS
> 0);
4311 -- If the saved checks stack overflowed, then we killed all checks, so
4312 -- setting the number of saved checks back to zero is correct. This
4313 -- should never occur in practice.
4315 if Saved_Checks_TOS
> Saved_Checks_Stack
'Last then
4316 Num_Saved_Checks
:= 0;
4318 -- In the normal case, restore the number of saved checks from the top
4322 Num_Saved_Checks
:= Saved_Checks_Stack
(Saved_Checks_TOS
);
4324 if Debug_Flag_CC
then
4325 w
("Conditional_Statements_End: Num_Saved_Checks = ",
4330 Saved_Checks_TOS
:= Saved_Checks_TOS
- 1;
4331 end Conditional_Statements_End
;
4333 -------------------------
4334 -- Convert_From_Bignum --
4335 -------------------------
4337 function Convert_From_Bignum
(N
: Node_Id
) return Node_Id
is
4338 Loc
: constant Source_Ptr
:= Sloc
(N
);
4341 pragma Assert
(Is_RTE
(Etype
(N
), RE_Bignum
));
4343 -- Construct call From Bignum
4346 Make_Function_Call
(Loc
,
4348 New_Occurrence_Of
(RTE
(RE_From_Bignum
), Loc
),
4349 Parameter_Associations
=> New_List
(Relocate_Node
(N
)));
4350 end Convert_From_Bignum
;
4352 -----------------------
4353 -- Convert_To_Bignum --
4354 -----------------------
4356 function Convert_To_Bignum
(N
: Node_Id
) return Node_Id
is
4357 Loc
: constant Source_Ptr
:= Sloc
(N
);
4360 -- Nothing to do if Bignum already except call Relocate_Node
4362 if Is_RTE
(Etype
(N
), RE_Bignum
) then
4363 return Relocate_Node
(N
);
4365 -- Otherwise construct call to To_Bignum, converting the operand to the
4366 -- required Long_Long_Integer form.
4369 pragma Assert
(Is_Signed_Integer_Type
(Etype
(N
)));
4371 Make_Function_Call
(Loc
,
4373 New_Occurrence_Of
(RTE
(RE_To_Bignum
), Loc
),
4374 Parameter_Associations
=> New_List
(
4375 Convert_To
(Standard_Long_Long_Integer
, Relocate_Node
(N
))));
4377 end Convert_To_Bignum
;
4379 ---------------------
4380 -- Determine_Range --
4381 ---------------------
4383 Cache_Size
: constant := 2 ** 10;
4384 type Cache_Index
is range 0 .. Cache_Size
- 1;
4385 -- Determine size of below cache (power of 2 is more efficient)
4387 Determine_Range_Cache_N
: array (Cache_Index
) of Node_Id
;
4388 Determine_Range_Cache_V
: array (Cache_Index
) of Boolean;
4389 Determine_Range_Cache_Lo
: array (Cache_Index
) of Uint
;
4390 Determine_Range_Cache_Hi
: array (Cache_Index
) of Uint
;
4391 Determine_Range_Cache_Lo_R
: array (Cache_Index
) of Ureal
;
4392 Determine_Range_Cache_Hi_R
: array (Cache_Index
) of Ureal
;
4393 -- The above arrays are used to implement a small direct cache for
4394 -- Determine_Range and Determine_Range_R calls. Because of the way these
4395 -- subprograms recursively traces subexpressions, and because overflow
4396 -- checking calls the routine on the way up the tree, a quadratic behavior
4397 -- can otherwise be encountered in large expressions. The cache entry for
4398 -- node N is stored in the (N mod Cache_Size) entry, and can be validated
4399 -- by checking the actual node value stored there. The Range_Cache_V array
4400 -- records the setting of Assume_Valid for the cache entry.
4402 procedure Determine_Range
4407 Assume_Valid
: Boolean := False)
4409 Typ
: Entity_Id
:= Etype
(N
);
4410 -- Type to use, may get reset to base type for possibly invalid entity
4414 -- Lo and Hi bounds of left operand
4416 Lo_Right
: Uint
:= No_Uint
;
4417 Hi_Right
: Uint
:= No_Uint
;
4418 -- Lo and Hi bounds of right (or only) operand
4421 -- Temp variable used to hold a bound node
4424 -- High bound of base type of expression
4428 -- Refined values for low and high bounds, after tightening
4431 -- Used in lower level calls to indicate if call succeeded
4433 Cindex
: Cache_Index
;
4434 -- Used to search cache
4439 function OK_Operands
return Boolean;
4440 -- Used for binary operators. Determines the ranges of the left and
4441 -- right operands, and if they are both OK, returns True, and puts
4442 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left.
4448 function OK_Operands
return Boolean is
4451 (Left_Opnd
(N
), OK1
, Lo_Left
, Hi_Left
, Assume_Valid
);
4458 (Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
, Assume_Valid
);
4462 -- Start of processing for Determine_Range
4465 -- Prevent junk warnings by initializing range variables
4472 -- For temporary constants internally generated to remove side effects
4473 -- we must use the corresponding expression to determine the range of
4474 -- the expression. But note that the expander can also generate
4475 -- constants in other cases, including deferred constants.
4477 if Is_Entity_Name
(N
)
4478 and then Nkind
(Parent
(Entity
(N
))) = N_Object_Declaration
4479 and then Ekind
(Entity
(N
)) = E_Constant
4480 and then Is_Internal_Name
(Chars
(Entity
(N
)))
4482 if Present
(Expression
(Parent
(Entity
(N
)))) then
4484 (Expression
(Parent
(Entity
(N
))), OK
, Lo
, Hi
, Assume_Valid
);
4486 elsif Present
(Full_View
(Entity
(N
))) then
4488 (Expression
(Parent
(Full_View
(Entity
(N
)))),
4489 OK
, Lo
, Hi
, Assume_Valid
);
4497 -- If type is not defined, we can't determine its range
4501 -- We don't deal with anything except discrete types
4503 or else not Is_Discrete_Type
(Typ
)
4505 -- Don't deal with enumerated types with non-standard representation
4507 or else (Is_Enumeration_Type
(Typ
)
4508 and then Present
(Enum_Pos_To_Rep
(Base_Type
(Typ
))))
4510 -- Ignore type for which an error has been posted, since range in
4511 -- this case may well be a bogosity deriving from the error. Also
4512 -- ignore if error posted on the reference node.
4514 or else Error_Posted
(N
) or else Error_Posted
(Typ
)
4520 -- For all other cases, we can determine the range
4524 -- If value is compile time known, then the possible range is the one
4525 -- value that we know this expression definitely has.
4527 if Compile_Time_Known_Value
(N
) then
4528 Lo
:= Expr_Value
(N
);
4533 -- Return if already in the cache
4535 Cindex
:= Cache_Index
(N
mod Cache_Size
);
4537 if Determine_Range_Cache_N
(Cindex
) = N
4539 Determine_Range_Cache_V
(Cindex
) = Assume_Valid
4541 Lo
:= Determine_Range_Cache_Lo
(Cindex
);
4542 Hi
:= Determine_Range_Cache_Hi
(Cindex
);
4546 -- Otherwise, start by finding the bounds of the type of the expression,
4547 -- the value cannot be outside this range (if it is, then we have an
4548 -- overflow situation, which is a separate check, we are talking here
4549 -- only about the expression value).
4551 -- First a check, never try to find the bounds of a generic type, since
4552 -- these bounds are always junk values, and it is only valid to look at
4553 -- the bounds in an instance.
4555 if Is_Generic_Type
(Typ
) then
4560 -- First step, change to use base type unless we know the value is valid
4562 if (Is_Entity_Name
(N
) and then Is_Known_Valid
(Entity
(N
)))
4563 or else Assume_No_Invalid_Values
4564 or else Assume_Valid
4568 Typ
:= Underlying_Type
(Base_Type
(Typ
));
4571 -- Retrieve the base type. Handle the case where the base type is a
4572 -- private enumeration type.
4574 Btyp
:= Base_Type
(Typ
);
4576 if Is_Private_Type
(Btyp
) and then Present
(Full_View
(Btyp
)) then
4577 Btyp
:= Full_View
(Btyp
);
4580 -- We use the actual bound unless it is dynamic, in which case use the
4581 -- corresponding base type bound if possible. If we can't get a bound
4582 -- then we figure we can't determine the range (a peculiar case, that
4583 -- perhaps cannot happen, but there is no point in bombing in this
4584 -- optimization circuit.
4586 -- First the low bound
4588 Bound
:= Type_Low_Bound
(Typ
);
4590 if Compile_Time_Known_Value
(Bound
) then
4591 Lo
:= Expr_Value
(Bound
);
4593 elsif Compile_Time_Known_Value
(Type_Low_Bound
(Btyp
)) then
4594 Lo
:= Expr_Value
(Type_Low_Bound
(Btyp
));
4601 -- Now the high bound
4603 Bound
:= Type_High_Bound
(Typ
);
4605 -- We need the high bound of the base type later on, and this should
4606 -- always be compile time known. Again, it is not clear that this
4607 -- can ever be false, but no point in bombing.
4609 if Compile_Time_Known_Value
(Type_High_Bound
(Btyp
)) then
4610 Hbound
:= Expr_Value
(Type_High_Bound
(Btyp
));
4618 -- If we have a static subtype, then that may have a tighter bound so
4619 -- use the upper bound of the subtype instead in this case.
4621 if Compile_Time_Known_Value
(Bound
) then
4622 Hi
:= Expr_Value
(Bound
);
4625 -- We may be able to refine this value in certain situations. If any
4626 -- refinement is possible, then Lor and Hir are set to possibly tighter
4627 -- bounds, and OK1 is set to True.
4631 -- For unary plus, result is limited by range of operand
4635 (Right_Opnd
(N
), OK1
, Lor
, Hir
, Assume_Valid
);
4637 -- For unary minus, determine range of operand, and negate it
4641 (Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
, Assume_Valid
);
4648 -- For binary addition, get range of each operand and do the
4649 -- addition to get the result range.
4653 Lor
:= Lo_Left
+ Lo_Right
;
4654 Hir
:= Hi_Left
+ Hi_Right
;
4657 -- Division is tricky. The only case we consider is where the right
4658 -- operand is a positive constant, and in this case we simply divide
4659 -- the bounds of the left operand
4663 if Lo_Right
= Hi_Right
4664 and then Lo_Right
> 0
4666 Lor
:= Lo_Left
/ Lo_Right
;
4667 Hir
:= Hi_Left
/ Lo_Right
;
4673 -- For binary subtraction, get range of each operand and do the worst
4674 -- case subtraction to get the result range.
4676 when N_Op_Subtract
=>
4678 Lor
:= Lo_Left
- Hi_Right
;
4679 Hir
:= Hi_Left
- Lo_Right
;
4682 -- For MOD, if right operand is a positive constant, then result must
4683 -- be in the allowable range of mod results.
4687 if Lo_Right
= Hi_Right
4688 and then Lo_Right
/= 0
4690 if Lo_Right
> 0 then
4692 Hir
:= Lo_Right
- 1;
4694 else -- Lo_Right < 0
4695 Lor
:= Lo_Right
+ 1;
4704 -- For REM, if right operand is a positive constant, then result must
4705 -- be in the allowable range of mod results.
4709 if Lo_Right
= Hi_Right
and then Lo_Right
/= 0 then
4711 Dval
: constant Uint
:= (abs Lo_Right
) - 1;
4714 -- The sign of the result depends on the sign of the
4715 -- dividend (but not on the sign of the divisor, hence
4716 -- the abs operation above).
4736 -- Attribute reference cases
4738 when N_Attribute_Reference
=>
4739 case Attribute_Name
(N
) is
4741 -- For Pos/Val attributes, we can refine the range using the
4742 -- possible range of values of the attribute expression.
4748 (First
(Expressions
(N
)), OK1
, Lor
, Hir
, Assume_Valid
);
4750 -- For Length attribute, use the bounds of the corresponding
4751 -- index type to refine the range.
4755 Atyp
: Entity_Id
:= Etype
(Prefix
(N
));
4763 if Is_Access_Type
(Atyp
) then
4764 Atyp
:= Designated_Type
(Atyp
);
4767 -- For string literal, we know exact value
4769 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
4771 Lo
:= String_Literal_Length
(Atyp
);
4772 Hi
:= String_Literal_Length
(Atyp
);
4776 -- Otherwise check for expression given
4778 if No
(Expressions
(N
)) then
4782 UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
4785 Indx
:= First_Index
(Atyp
);
4786 for J
in 2 .. Inum
loop
4787 Indx
:= Next_Index
(Indx
);
4790 -- If the index type is a formal type or derived from
4791 -- one, the bounds are not static.
4793 if Is_Generic_Type
(Root_Type
(Etype
(Indx
))) then
4799 (Type_Low_Bound
(Etype
(Indx
)), OK1
, LL
, LU
,
4804 (Type_High_Bound
(Etype
(Indx
)), OK1
, UL
, UU
,
4809 -- The maximum value for Length is the biggest
4810 -- possible gap between the values of the bounds.
4811 -- But of course, this value cannot be negative.
4813 Hir
:= UI_Max
(Uint_0
, UU
- LL
+ 1);
4815 -- For constrained arrays, the minimum value for
4816 -- Length is taken from the actual value of the
4817 -- bounds, since the index will be exactly of this
4820 if Is_Constrained
(Atyp
) then
4821 Lor
:= UI_Max
(Uint_0
, UL
- LU
+ 1);
4823 -- For an unconstrained array, the minimum value
4824 -- for length is always zero.
4833 -- No special handling for other attributes
4834 -- Probably more opportunities exist here???
4841 when N_Type_Conversion
=>
4843 -- For type conversion from one discrete type to another, we can
4844 -- refine the range using the converted value.
4846 if Is_Discrete_Type
(Etype
(Expression
(N
))) then
4847 Determine_Range
(Expression
(N
), OK1
, Lor
, Hir
, Assume_Valid
);
4849 -- When converting a float to an integer type, determine the range
4850 -- in real first, and then convert the bounds using UR_To_Uint
4851 -- which correctly rounds away from zero when half way between two
4852 -- integers, as required by normal Ada 95 rounding semantics. It
4853 -- is only possible because analysis in GNATprove rules out the
4854 -- possibility of a NaN or infinite value.
4856 elsif GNATprove_Mode
4857 and then Is_Floating_Point_Type
(Etype
(Expression
(N
)))
4860 Lor_Real
, Hir_Real
: Ureal
;
4862 Determine_Range_R
(Expression
(N
), OK1
, Lor_Real
, Hir_Real
,
4866 Lor
:= UR_To_Uint
(Lor_Real
);
4867 Hir
:= UR_To_Uint
(Hir_Real
);
4875 -- Nothing special to do for all other expression kinds
4883 -- At this stage, if OK1 is true, then we know that the actual result of
4884 -- the computed expression is in the range Lor .. Hir. We can use this
4885 -- to restrict the possible range of results.
4889 -- If the refined value of the low bound is greater than the type
4890 -- low bound, then reset it to the more restrictive value. However,
4891 -- we do NOT do this for the case of a modular type where the
4892 -- possible upper bound on the value is above the base type high
4893 -- bound, because that means the result could wrap.
4896 and then not (Is_Modular_Integer_Type
(Typ
) and then Hir
> Hbound
)
4901 -- Similarly, if the refined value of the high bound is less than the
4902 -- value so far, then reset it to the more restrictive value. Again,
4903 -- we do not do this if the refined low bound is negative for a
4904 -- modular type, since this would wrap.
4907 and then not (Is_Modular_Integer_Type
(Typ
) and then Lor
< Uint_0
)
4913 -- Set cache entry for future call and we are all done
4915 Determine_Range_Cache_N
(Cindex
) := N
;
4916 Determine_Range_Cache_V
(Cindex
) := Assume_Valid
;
4917 Determine_Range_Cache_Lo
(Cindex
) := Lo
;
4918 Determine_Range_Cache_Hi
(Cindex
) := Hi
;
4921 -- If any exception occurs, it means that we have some bug in the compiler,
4922 -- possibly triggered by a previous error, or by some unforeseen peculiar
4923 -- occurrence. However, this is only an optimization attempt, so there is
4924 -- really no point in crashing the compiler. Instead we just decide, too
4925 -- bad, we can't figure out a range in this case after all.
4930 -- Debug flag K disables this behavior (useful for debugging)
4932 if Debug_Flag_K
then
4940 end Determine_Range
;
4942 -----------------------
4943 -- Determine_Range_R --
4944 -----------------------
4946 procedure Determine_Range_R
4951 Assume_Valid
: Boolean := False)
4953 Typ
: Entity_Id
:= Etype
(N
);
4954 -- Type to use, may get reset to base type for possibly invalid entity
4958 -- Lo and Hi bounds of left operand
4960 Lo_Right
: Ureal
:= No_Ureal
;
4961 Hi_Right
: Ureal
:= No_Ureal
;
4962 -- Lo and Hi bounds of right (or only) operand
4965 -- Temp variable used to hold a bound node
4968 -- High bound of base type of expression
4972 -- Refined values for low and high bounds, after tightening
4975 -- Used in lower level calls to indicate if call succeeded
4977 Cindex
: Cache_Index
;
4978 -- Used to search cache
4983 function OK_Operands
return Boolean;
4984 -- Used for binary operators. Determines the ranges of the left and
4985 -- right operands, and if they are both OK, returns True, and puts
4986 -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left.
4988 function Round_Machine
(B
: Ureal
) return Ureal
;
4989 -- B is a real bound. Round it using mode Round_Even.
4995 function OK_Operands
return Boolean is
4998 (Left_Opnd
(N
), OK1
, Lo_Left
, Hi_Left
, Assume_Valid
);
5005 (Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
, Assume_Valid
);
5013 function Round_Machine
(B
: Ureal
) return Ureal
is
5015 return Machine
(Typ
, B
, Round_Even
, N
);
5018 -- Start of processing for Determine_Range_R
5021 -- Prevent junk warnings by initializing range variables
5028 -- For temporary constants internally generated to remove side effects
5029 -- we must use the corresponding expression to determine the range of
5030 -- the expression. But note that the expander can also generate
5031 -- constants in other cases, including deferred constants.
5033 if Is_Entity_Name
(N
)
5034 and then Nkind
(Parent
(Entity
(N
))) = N_Object_Declaration
5035 and then Ekind
(Entity
(N
)) = E_Constant
5036 and then Is_Internal_Name
(Chars
(Entity
(N
)))
5038 if Present
(Expression
(Parent
(Entity
(N
)))) then
5040 (Expression
(Parent
(Entity
(N
))), OK
, Lo
, Hi
, Assume_Valid
);
5042 elsif Present
(Full_View
(Entity
(N
))) then
5044 (Expression
(Parent
(Full_View
(Entity
(N
)))),
5045 OK
, Lo
, Hi
, Assume_Valid
);
5054 -- If type is not defined, we can't determine its range
5058 -- We don't deal with anything except IEEE floating-point types
5060 or else not Is_Floating_Point_Type
(Typ
)
5061 or else Float_Rep
(Typ
) /= IEEE_Binary
5063 -- Ignore type for which an error has been posted, since range in
5064 -- this case may well be a bogosity deriving from the error. Also
5065 -- ignore if error posted on the reference node.
5067 or else Error_Posted
(N
) or else Error_Posted
(Typ
)
5073 -- For all other cases, we can determine the range
5077 -- If value is compile time known, then the possible range is the one
5078 -- value that we know this expression definitely has.
5080 if Compile_Time_Known_Value
(N
) then
5081 Lo
:= Expr_Value_R
(N
);
5086 -- Return if already in the cache
5088 Cindex
:= Cache_Index
(N
mod Cache_Size
);
5090 if Determine_Range_Cache_N
(Cindex
) = N
5092 Determine_Range_Cache_V
(Cindex
) = Assume_Valid
5094 Lo
:= Determine_Range_Cache_Lo_R
(Cindex
);
5095 Hi
:= Determine_Range_Cache_Hi_R
(Cindex
);
5099 -- Otherwise, start by finding the bounds of the type of the expression,
5100 -- the value cannot be outside this range (if it is, then we have an
5101 -- overflow situation, which is a separate check, we are talking here
5102 -- only about the expression value).
5104 -- First a check, never try to find the bounds of a generic type, since
5105 -- these bounds are always junk values, and it is only valid to look at
5106 -- the bounds in an instance.
5108 if Is_Generic_Type
(Typ
) then
5113 -- First step, change to use base type unless we know the value is valid
5115 if (Is_Entity_Name
(N
) and then Is_Known_Valid
(Entity
(N
)))
5116 or else Assume_No_Invalid_Values
5117 or else Assume_Valid
5121 Typ
:= Underlying_Type
(Base_Type
(Typ
));
5124 -- Retrieve the base type. Handle the case where the base type is a
5127 Btyp
:= Base_Type
(Typ
);
5129 if Is_Private_Type
(Btyp
) and then Present
(Full_View
(Btyp
)) then
5130 Btyp
:= Full_View
(Btyp
);
5133 -- We use the actual bound unless it is dynamic, in which case use the
5134 -- corresponding base type bound if possible. If we can't get a bound
5135 -- then we figure we can't determine the range (a peculiar case, that
5136 -- perhaps cannot happen, but there is no point in bombing in this
5137 -- optimization circuit).
5139 -- First the low bound
5141 Bound
:= Type_Low_Bound
(Typ
);
5143 if Compile_Time_Known_Value
(Bound
) then
5144 Lo
:= Expr_Value_R
(Bound
);
5146 elsif Compile_Time_Known_Value
(Type_Low_Bound
(Btyp
)) then
5147 Lo
:= Expr_Value_R
(Type_Low_Bound
(Btyp
));
5154 -- Now the high bound
5156 Bound
:= Type_High_Bound
(Typ
);
5158 -- We need the high bound of the base type later on, and this should
5159 -- always be compile time known. Again, it is not clear that this
5160 -- can ever be false, but no point in bombing.
5162 if Compile_Time_Known_Value
(Type_High_Bound
(Btyp
)) then
5163 Hbound
:= Expr_Value_R
(Type_High_Bound
(Btyp
));
5171 -- If we have a static subtype, then that may have a tighter bound so
5172 -- use the upper bound of the subtype instead in this case.
5174 if Compile_Time_Known_Value
(Bound
) then
5175 Hi
:= Expr_Value_R
(Bound
);
5178 -- We may be able to refine this value in certain situations. If any
5179 -- refinement is possible, then Lor and Hir are set to possibly tighter
5180 -- bounds, and OK1 is set to True.
5184 -- For unary plus, result is limited by range of operand
5188 (Right_Opnd
(N
), OK1
, Lor
, Hir
, Assume_Valid
);
5190 -- For unary minus, determine range of operand, and negate it
5194 (Right_Opnd
(N
), OK1
, Lo_Right
, Hi_Right
, Assume_Valid
);
5201 -- For binary addition, get range of each operand and do the
5202 -- addition to get the result range.
5206 Lor
:= Round_Machine
(Lo_Left
+ Lo_Right
);
5207 Hir
:= Round_Machine
(Hi_Left
+ Hi_Right
);
5210 -- For binary subtraction, get range of each operand and do the worst
5211 -- case subtraction to get the result range.
5213 when N_Op_Subtract
=>
5215 Lor
:= Round_Machine
(Lo_Left
- Hi_Right
);
5216 Hir
:= Round_Machine
(Hi_Left
- Lo_Right
);
5219 -- For multiplication, get range of each operand and do the
5220 -- four multiplications to get the result range.
5222 when N_Op_Multiply
=>
5225 M1
: constant Ureal
:= Round_Machine
(Lo_Left
* Lo_Right
);
5226 M2
: constant Ureal
:= Round_Machine
(Lo_Left
* Hi_Right
);
5227 M3
: constant Ureal
:= Round_Machine
(Hi_Left
* Lo_Right
);
5228 M4
: constant Ureal
:= Round_Machine
(Hi_Left
* Hi_Right
);
5231 Lor
:= UR_Min
(UR_Min
(M1
, M2
), UR_Min
(M3
, M4
));
5232 Hir
:= UR_Max
(UR_Max
(M1
, M2
), UR_Max
(M3
, M4
));
5236 -- For division, consider separately the cases where the right
5237 -- operand is positive or negative. Otherwise, the right operand
5238 -- can be arbitrarily close to zero, so the result is likely to
5239 -- be unbounded in one direction, do not attempt to compute it.
5244 -- Right operand is positive
5246 if Lo_Right
> Ureal_0
then
5248 -- If the low bound of the left operand is negative, obtain
5249 -- the overall low bound by dividing it by the smallest
5250 -- value of the right operand, and otherwise by the largest
5251 -- value of the right operand.
5253 if Lo_Left
< Ureal_0
then
5254 Lor
:= Round_Machine
(Lo_Left
/ Lo_Right
);
5256 Lor
:= Round_Machine
(Lo_Left
/ Hi_Right
);
5259 -- If the high bound of the left operand is negative, obtain
5260 -- the overall high bound by dividing it by the largest
5261 -- value of the right operand, and otherwise by the
5262 -- smallest value of the right operand.
5264 if Hi_Left
< Ureal_0
then
5265 Hir
:= Round_Machine
(Hi_Left
/ Hi_Right
);
5267 Hir
:= Round_Machine
(Hi_Left
/ Lo_Right
);
5270 -- Right operand is negative
5272 elsif Hi_Right
< Ureal_0
then
5274 -- If the low bound of the left operand is negative, obtain
5275 -- the overall low bound by dividing it by the largest
5276 -- value of the right operand, and otherwise by the smallest
5277 -- value of the right operand.
5279 if Lo_Left
< Ureal_0
then
5280 Lor
:= Round_Machine
(Lo_Left
/ Hi_Right
);
5282 Lor
:= Round_Machine
(Lo_Left
/ Lo_Right
);
5285 -- If the high bound of the left operand is negative, obtain
5286 -- the overall high bound by dividing it by the smallest
5287 -- value of the right operand, and otherwise by the
5288 -- largest value of the right operand.
5290 if Hi_Left
< Ureal_0
then
5291 Hir
:= Round_Machine
(Hi_Left
/ Lo_Right
);
5293 Hir
:= Round_Machine
(Hi_Left
/ Hi_Right
);
5301 when N_Type_Conversion
=>
5303 -- For type conversion from one floating-point type to another, we
5304 -- can refine the range using the converted value.
5306 if Is_Floating_Point_Type
(Etype
(Expression
(N
))) then
5307 Determine_Range_R
(Expression
(N
), OK1
, Lor
, Hir
, Assume_Valid
);
5309 -- When converting an integer to a floating-point type, determine
5310 -- the range in integer first, and then convert the bounds.
5312 elsif Is_Discrete_Type
(Etype
(Expression
(N
))) then
5319 (Expression
(N
), OK1
, Lor_Int
, Hir_Int
, Assume_Valid
);
5322 Lor
:= Round_Machine
(UR_From_Uint
(Lor_Int
));
5323 Hir
:= Round_Machine
(UR_From_Uint
(Hir_Int
));
5331 -- Nothing special to do for all other expression kinds
5339 -- At this stage, if OK1 is true, then we know that the actual result of
5340 -- the computed expression is in the range Lor .. Hir. We can use this
5341 -- to restrict the possible range of results.
5345 -- If the refined value of the low bound is greater than the type
5346 -- low bound, then reset it to the more restrictive value.
5352 -- Similarly, if the refined value of the high bound is less than the
5353 -- value so far, then reset it to the more restrictive value.
5360 -- Set cache entry for future call and we are all done
5362 Determine_Range_Cache_N
(Cindex
) := N
;
5363 Determine_Range_Cache_V
(Cindex
) := Assume_Valid
;
5364 Determine_Range_Cache_Lo_R
(Cindex
) := Lo
;
5365 Determine_Range_Cache_Hi_R
(Cindex
) := Hi
;
5368 -- If any exception occurs, it means that we have some bug in the compiler,
5369 -- possibly triggered by a previous error, or by some unforeseen peculiar
5370 -- occurrence. However, this is only an optimization attempt, so there is
5371 -- really no point in crashing the compiler. Instead we just decide, too
5372 -- bad, we can't figure out a range in this case after all.
5377 -- Debug flag K disables this behavior (useful for debugging)
5379 if Debug_Flag_K
then
5387 end Determine_Range_R
;
5389 ------------------------------------
5390 -- Discriminant_Checks_Suppressed --
5391 ------------------------------------
5393 function Discriminant_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5396 if Is_Unchecked_Union
(E
) then
5398 elsif Checks_May_Be_Suppressed
(E
) then
5399 return Is_Check_Suppressed
(E
, Discriminant_Check
);
5403 return Scope_Suppress
.Suppress
(Discriminant_Check
);
5404 end Discriminant_Checks_Suppressed
;
5406 --------------------------------
5407 -- Division_Checks_Suppressed --
5408 --------------------------------
5410 function Division_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5412 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
5413 return Is_Check_Suppressed
(E
, Division_Check
);
5415 return Scope_Suppress
.Suppress
(Division_Check
);
5417 end Division_Checks_Suppressed
;
5419 --------------------------------------
5420 -- Duplicated_Tag_Checks_Suppressed --
5421 --------------------------------------
5423 function Duplicated_Tag_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5425 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
5426 return Is_Check_Suppressed
(E
, Duplicated_Tag_Check
);
5428 return Scope_Suppress
.Suppress
(Duplicated_Tag_Check
);
5430 end Duplicated_Tag_Checks_Suppressed
;
5432 -----------------------------------
5433 -- Elaboration_Checks_Suppressed --
5434 -----------------------------------
5436 function Elaboration_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
5438 -- The complication in this routine is that if we are in the dynamic
5439 -- model of elaboration, we also check All_Checks, since All_Checks
5440 -- does not set Elaboration_Check explicitly.
5443 if Kill_Elaboration_Checks
(E
) then
5446 elsif Checks_May_Be_Suppressed
(E
) then
5447 if Is_Check_Suppressed
(E
, Elaboration_Check
) then
5450 elsif Dynamic_Elaboration_Checks
then
5451 return Is_Check_Suppressed
(E
, All_Checks
);
5459 if Scope_Suppress
.Suppress
(Elaboration_Check
) then
5462 elsif Dynamic_Elaboration_Checks
then
5463 return Scope_Suppress
.Suppress
(All_Checks
);
5468 end Elaboration_Checks_Suppressed
;
5470 ---------------------------
5471 -- Enable_Overflow_Check --
5472 ---------------------------
5474 procedure Enable_Overflow_Check
(N
: Node_Id
) is
5475 Typ
: constant Entity_Id
:= Base_Type
(Etype
(N
));
5476 Mode
: constant Overflow_Mode_Type
:= Overflow_Check_Mode
;
5484 Do_Ovflow_Check
: Boolean;
5487 if Debug_Flag_CC
then
5488 w
("Enable_Overflow_Check for node ", Int
(N
));
5489 Write_Str
(" Source location = ");
5494 -- No check if overflow checks suppressed for type of node
5496 if Overflow_Checks_Suppressed
(Etype
(N
)) then
5499 -- Nothing to do for unsigned integer types, which do not overflow
5501 elsif Is_Modular_Integer_Type
(Typ
) then
5505 -- This is the point at which processing for STRICT mode diverges
5506 -- from processing for MINIMIZED/ELIMINATED modes. This divergence is
5507 -- probably more extreme that it needs to be, but what is going on here
5508 -- is that when we introduced MINIMIZED/ELIMINATED modes, we wanted
5509 -- to leave the processing for STRICT mode untouched. There were
5510 -- two reasons for this. First it avoided any incompatible change of
5511 -- behavior. Second, it guaranteed that STRICT mode continued to be
5514 -- The big difference is that in STRICT mode there is a fair amount of
5515 -- circuitry to try to avoid setting the Do_Overflow_Check flag if we
5516 -- know that no check is needed. We skip all that in the two new modes,
5517 -- since really overflow checking happens over a whole subtree, and we
5518 -- do the corresponding optimizations later on when applying the checks.
5520 if Mode
in Minimized_Or_Eliminated
then
5521 if not (Overflow_Checks_Suppressed
(Etype
(N
)))
5522 and then not (Is_Entity_Name
(N
)
5523 and then Overflow_Checks_Suppressed
(Entity
(N
)))
5525 Activate_Overflow_Check
(N
);
5528 if Debug_Flag_CC
then
5529 w
("Minimized/Eliminated mode");
5535 -- Remainder of processing is for STRICT case, and is unchanged from
5536 -- earlier versions preceding the addition of MINIMIZED/ELIMINATED.
5538 -- Nothing to do if the range of the result is known OK. We skip this
5539 -- for conversions, since the caller already did the check, and in any
5540 -- case the condition for deleting the check for a type conversion is
5543 if Nkind
(N
) /= N_Type_Conversion
then
5544 Determine_Range
(N
, OK
, Lo
, Hi
, Assume_Valid
=> True);
5546 -- Note in the test below that we assume that the range is not OK
5547 -- if a bound of the range is equal to that of the type. That's not
5548 -- quite accurate but we do this for the following reasons:
5550 -- a) The way that Determine_Range works, it will typically report
5551 -- the bounds of the value as being equal to the bounds of the
5552 -- type, because it either can't tell anything more precise, or
5553 -- does not think it is worth the effort to be more precise.
5555 -- b) It is very unusual to have a situation in which this would
5556 -- generate an unnecessary overflow check (an example would be
5557 -- a subtype with a range 0 .. Integer'Last - 1 to which the
5558 -- literal value one is added).
5560 -- c) The alternative is a lot of special casing in this routine
5561 -- which would partially duplicate Determine_Range processing.
5564 Do_Ovflow_Check
:= True;
5566 -- Note that the following checks are quite deliberately > and <
5567 -- rather than >= and <= as explained above.
5569 if Lo
> Expr_Value
(Type_Low_Bound
(Typ
))
5571 Hi
< Expr_Value
(Type_High_Bound
(Typ
))
5573 Do_Ovflow_Check
:= False;
5575 -- Despite the comments above, it is worth dealing specially with
5576 -- division specially. The only case where integer division can
5577 -- overflow is (largest negative number) / (-1). So we will do
5578 -- an extra range analysis to see if this is possible.
5580 elsif Nkind
(N
) = N_Op_Divide
then
5582 (Left_Opnd
(N
), OK
, Lo
, Hi
, Assume_Valid
=> True);
5584 if OK
and then Lo
> Expr_Value
(Type_Low_Bound
(Typ
)) then
5585 Do_Ovflow_Check
:= False;
5589 (Right_Opnd
(N
), OK
, Lo
, Hi
, Assume_Valid
=> True);
5591 if OK
and then (Lo
> Uint_Minus_1
5595 Do_Ovflow_Check
:= False;
5600 -- If no overflow check required, we are done
5602 if not Do_Ovflow_Check
then
5603 if Debug_Flag_CC
then
5604 w
("No overflow check required");
5612 -- If not in optimizing mode, set flag and we are done. We are also done
5613 -- (and just set the flag) if the type is not a discrete type, since it
5614 -- is not worth the effort to eliminate checks for other than discrete
5615 -- types. In addition, we take this same path if we have stored the
5616 -- maximum number of checks possible already (a very unlikely situation,
5617 -- but we do not want to blow up).
5619 if Optimization_Level
= 0
5620 or else not Is_Discrete_Type
(Etype
(N
))
5621 or else Num_Saved_Checks
= Saved_Checks
'Last
5623 Activate_Overflow_Check
(N
);
5625 if Debug_Flag_CC
then
5626 w
("Optimization off");
5632 -- Otherwise evaluate and check the expression
5637 Target_Type
=> Empty
,
5643 if Debug_Flag_CC
then
5644 w
("Called Find_Check");
5648 w
(" Check_Num = ", Chk
);
5649 w
(" Ent = ", Int
(Ent
));
5650 Write_Str
(" Ofs = ");
5655 -- If check is not of form to optimize, then set flag and we are done
5658 Activate_Overflow_Check
(N
);
5662 -- If check is already performed, then return without setting flag
5665 if Debug_Flag_CC
then
5666 w
("Check suppressed!");
5672 -- Here we will make a new entry for the new check
5674 Activate_Overflow_Check
(N
);
5675 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
5676 Saved_Checks
(Num_Saved_Checks
) :=
5681 Target_Type
=> Empty
);
5683 if Debug_Flag_CC
then
5684 w
("Make new entry, check number = ", Num_Saved_Checks
);
5685 w
(" Entity = ", Int
(Ent
));
5686 Write_Str
(" Offset = ");
5688 w
(" Check_Type = O");
5689 w
(" Target_Type = Empty");
5692 -- If we get an exception, then something went wrong, probably because of
5693 -- an error in the structure of the tree due to an incorrect program. Or
5694 -- it may be a bug in the optimization circuit. In either case the safest
5695 -- thing is simply to set the check flag unconditionally.
5699 Activate_Overflow_Check
(N
);
5701 if Debug_Flag_CC
then
5702 w
(" exception occurred, overflow flag set");
5706 end Enable_Overflow_Check
;
5708 ------------------------
5709 -- Enable_Range_Check --
5710 ------------------------
5712 procedure Enable_Range_Check
(N
: Node_Id
) is
5721 -- Return if unchecked type conversion with range check killed. In this
5722 -- case we never set the flag (that's what Kill_Range_Check is about).
5724 if Nkind
(N
) = N_Unchecked_Type_Conversion
5725 and then Kill_Range_Check
(N
)
5730 -- Do not set range check flag if parent is assignment statement or
5731 -- object declaration with Suppress_Assignment_Checks flag set
5733 if Nkind_In
(Parent
(N
), N_Assignment_Statement
, N_Object_Declaration
)
5734 and then Suppress_Assignment_Checks
(Parent
(N
))
5739 -- Check for various cases where we should suppress the range check
5741 -- No check if range checks suppressed for type of node
5743 if Present
(Etype
(N
)) and then Range_Checks_Suppressed
(Etype
(N
)) then
5746 -- No check if node is an entity name, and range checks are suppressed
5747 -- for this entity, or for the type of this entity.
5749 elsif Is_Entity_Name
(N
)
5750 and then (Range_Checks_Suppressed
(Entity
(N
))
5751 or else Range_Checks_Suppressed
(Etype
(Entity
(N
))))
5755 -- No checks if index of array, and index checks are suppressed for
5756 -- the array object or the type of the array.
5758 elsif Nkind
(Parent
(N
)) = N_Indexed_Component
then
5760 Pref
: constant Node_Id
:= Prefix
(Parent
(N
));
5762 if Is_Entity_Name
(Pref
)
5763 and then Index_Checks_Suppressed
(Entity
(Pref
))
5766 elsif Index_Checks_Suppressed
(Etype
(Pref
)) then
5772 -- Debug trace output
5774 if Debug_Flag_CC
then
5775 w
("Enable_Range_Check for node ", Int
(N
));
5776 Write_Str
(" Source location = ");
5781 -- If not in optimizing mode, set flag and we are done. We are also done
5782 -- (and just set the flag) if the type is not a discrete type, since it
5783 -- is not worth the effort to eliminate checks for other than discrete
5784 -- types. In addition, we take this same path if we have stored the
5785 -- maximum number of checks possible already (a very unlikely situation,
5786 -- but we do not want to blow up).
5788 if Optimization_Level
= 0
5789 or else No
(Etype
(N
))
5790 or else not Is_Discrete_Type
(Etype
(N
))
5791 or else Num_Saved_Checks
= Saved_Checks
'Last
5793 Activate_Range_Check
(N
);
5795 if Debug_Flag_CC
then
5796 w
("Optimization off");
5802 -- Otherwise find out the target type
5806 -- For assignment, use left side subtype
5808 if Nkind
(P
) = N_Assignment_Statement
5809 and then Expression
(P
) = N
5811 Ttyp
:= Etype
(Name
(P
));
5813 -- For indexed component, use subscript subtype
5815 elsif Nkind
(P
) = N_Indexed_Component
then
5822 Atyp
:= Etype
(Prefix
(P
));
5824 if Is_Access_Type
(Atyp
) then
5825 Atyp
:= Designated_Type
(Atyp
);
5827 -- If the prefix is an access to an unconstrained array,
5828 -- perform check unconditionally: it depends on the bounds of
5829 -- an object and we cannot currently recognize whether the test
5830 -- may be redundant.
5832 if not Is_Constrained
(Atyp
) then
5833 Activate_Range_Check
(N
);
5837 -- Ditto if prefix is simply an unconstrained array. We used
5838 -- to think this case was OK, if the prefix was not an explicit
5839 -- dereference, but we have now seen a case where this is not
5840 -- true, so it is safer to just suppress the optimization in this
5841 -- case. The back end is getting better at eliminating redundant
5842 -- checks in any case, so the loss won't be important.
5844 elsif Is_Array_Type
(Atyp
)
5845 and then not Is_Constrained
(Atyp
)
5847 Activate_Range_Check
(N
);
5851 Indx
:= First_Index
(Atyp
);
5852 Subs
:= First
(Expressions
(P
));
5855 Ttyp
:= Etype
(Indx
);
5864 -- For now, ignore all other cases, they are not so interesting
5867 if Debug_Flag_CC
then
5868 w
(" target type not found, flag set");
5871 Activate_Range_Check
(N
);
5875 -- Evaluate and check the expression
5880 Target_Type
=> Ttyp
,
5886 if Debug_Flag_CC
then
5887 w
("Called Find_Check");
5888 w
("Target_Typ = ", Int
(Ttyp
));
5892 w
(" Check_Num = ", Chk
);
5893 w
(" Ent = ", Int
(Ent
));
5894 Write_Str
(" Ofs = ");
5899 -- If check is not of form to optimize, then set flag and we are done
5902 if Debug_Flag_CC
then
5903 w
(" expression not of optimizable type, flag set");
5906 Activate_Range_Check
(N
);
5910 -- If check is already performed, then return without setting flag
5913 if Debug_Flag_CC
then
5914 w
("Check suppressed!");
5920 -- Here we will make a new entry for the new check
5922 Activate_Range_Check
(N
);
5923 Num_Saved_Checks
:= Num_Saved_Checks
+ 1;
5924 Saved_Checks
(Num_Saved_Checks
) :=
5929 Target_Type
=> Ttyp
);
5931 if Debug_Flag_CC
then
5932 w
("Make new entry, check number = ", Num_Saved_Checks
);
5933 w
(" Entity = ", Int
(Ent
));
5934 Write_Str
(" Offset = ");
5936 w
(" Check_Type = R");
5937 w
(" Target_Type = ", Int
(Ttyp
));
5938 pg
(Union_Id
(Ttyp
));
5941 -- If we get an exception, then something went wrong, probably because of
5942 -- an error in the structure of the tree due to an incorrect program. Or
5943 -- it may be a bug in the optimization circuit. In either case the safest
5944 -- thing is simply to set the check flag unconditionally.
5948 Activate_Range_Check
(N
);
5950 if Debug_Flag_CC
then
5951 w
(" exception occurred, range flag set");
5955 end Enable_Range_Check
;
5961 procedure Ensure_Valid
5963 Holes_OK
: Boolean := False;
5964 Related_Id
: Entity_Id
:= Empty
;
5965 Is_Low_Bound
: Boolean := False;
5966 Is_High_Bound
: Boolean := False)
5968 Typ
: constant Entity_Id
:= Etype
(Expr
);
5971 -- Ignore call if we are not doing any validity checking
5973 if not Validity_Checks_On
then
5976 -- Ignore call if range or validity checks suppressed on entity or type
5978 elsif Range_Or_Validity_Checks_Suppressed
(Expr
) then
5981 -- No check required if expression is from the expander, we assume the
5982 -- expander will generate whatever checks are needed. Note that this is
5983 -- not just an optimization, it avoids infinite recursions.
5985 -- Unchecked conversions must be checked, unless they are initialized
5986 -- scalar values, as in a component assignment in an init proc.
5988 -- In addition, we force a check if Force_Validity_Checks is set
5990 elsif not Comes_From_Source
(Expr
)
5992 (Nkind
(Expr
) = N_Identifier
5993 and then Present
(Renamed_Object
(Entity
(Expr
)))
5994 and then Comes_From_Source
(Renamed_Object
(Entity
(Expr
))))
5995 and then not Force_Validity_Checks
5996 and then (Nkind
(Expr
) /= N_Unchecked_Type_Conversion
5997 or else Kill_Range_Check
(Expr
))
6001 -- No check required if expression is known to have valid value
6003 elsif Expr_Known_Valid
(Expr
) then
6006 -- No check needed within a generated predicate function. Validity
6007 -- of input value will have been checked earlier.
6009 elsif Ekind
(Current_Scope
) = E_Function
6010 and then Is_Predicate_Function
(Current_Scope
)
6014 -- Ignore case of enumeration with holes where the flag is set not to
6015 -- worry about holes, since no special validity check is needed
6017 elsif Is_Enumeration_Type
(Typ
)
6018 and then Has_Non_Standard_Rep
(Typ
)
6023 -- No check required on the left-hand side of an assignment
6025 elsif Nkind
(Parent
(Expr
)) = N_Assignment_Statement
6026 and then Expr
= Name
(Parent
(Expr
))
6030 -- No check on a universal real constant. The context will eventually
6031 -- convert it to a machine number for some target type, or report an
6034 elsif Nkind
(Expr
) = N_Real_Literal
6035 and then Etype
(Expr
) = Universal_Real
6039 -- If the expression denotes a component of a packed boolean array,
6040 -- no possible check applies. We ignore the old ACATS chestnuts that
6041 -- involve Boolean range True..True.
6043 -- Note: validity checks are generated for expressions that yield a
6044 -- scalar type, when it is possible to create a value that is outside of
6045 -- the type. If this is a one-bit boolean no such value exists. This is
6046 -- an optimization, and it also prevents compiler blowing up during the
6047 -- elaboration of improperly expanded packed array references.
6049 elsif Nkind
(Expr
) = N_Indexed_Component
6050 and then Is_Bit_Packed_Array
(Etype
(Prefix
(Expr
)))
6051 and then Root_Type
(Etype
(Expr
)) = Standard_Boolean
6055 -- For an expression with actions, we want to insert the validity check
6056 -- on the final Expression.
6058 elsif Nkind
(Expr
) = N_Expression_With_Actions
then
6059 Ensure_Valid
(Expression
(Expr
));
6062 -- An annoying special case. If this is an out parameter of a scalar
6063 -- type, then the value is not going to be accessed, therefore it is
6064 -- inappropriate to do any validity check at the call site.
6067 -- Only need to worry about scalar types
6069 if Is_Scalar_Type
(Typ
) then
6079 -- Find actual argument (which may be a parameter association)
6080 -- and the parent of the actual argument (the call statement)
6085 if Nkind
(P
) = N_Parameter_Association
then
6090 -- Only need to worry if we are argument of a procedure call
6091 -- since functions don't have out parameters. If this is an
6092 -- indirect or dispatching call, get signature from the
6095 if Nkind
(P
) = N_Procedure_Call_Statement
then
6096 L
:= Parameter_Associations
(P
);
6098 if Is_Entity_Name
(Name
(P
)) then
6099 E
:= Entity
(Name
(P
));
6101 pragma Assert
(Nkind
(Name
(P
)) = N_Explicit_Dereference
);
6102 E
:= Etype
(Name
(P
));
6105 -- Only need to worry if there are indeed actuals, and if
6106 -- this could be a procedure call, otherwise we cannot get a
6107 -- match (either we are not an argument, or the mode of the
6108 -- formal is not OUT). This test also filters out the
6111 if Is_Non_Empty_List
(L
) and then Is_Subprogram
(E
) then
6113 -- This is the loop through parameters, looking for an
6114 -- OUT parameter for which we are the argument.
6116 F
:= First_Formal
(E
);
6118 while Present
(F
) loop
6119 if Ekind
(F
) = E_Out_Parameter
and then A
= N
then
6132 -- If this is a boolean expression, only its elementary operands need
6133 -- checking: if they are valid, a boolean or short-circuit operation
6134 -- with them will be valid as well.
6136 if Base_Type
(Typ
) = Standard_Boolean
6138 (Nkind
(Expr
) in N_Op
or else Nkind
(Expr
) in N_Short_Circuit
)
6143 -- If we fall through, a validity check is required
6145 Insert_Valid_Check
(Expr
, Related_Id
, Is_Low_Bound
, Is_High_Bound
);
6147 if Is_Entity_Name
(Expr
)
6148 and then Safe_To_Capture_Value
(Expr
, Entity
(Expr
))
6150 Set_Is_Known_Valid
(Entity
(Expr
));
6154 ----------------------
6155 -- Expr_Known_Valid --
6156 ----------------------
6158 function Expr_Known_Valid
(Expr
: Node_Id
) return Boolean is
6159 Typ
: constant Entity_Id
:= Etype
(Expr
);
6162 -- Non-scalar types are always considered valid, since they never give
6163 -- rise to the issues of erroneous or bounded error behavior that are
6164 -- the concern. In formal reference manual terms the notion of validity
6165 -- only applies to scalar types. Note that even when packed arrays are
6166 -- represented using modular types, they are still arrays semantically,
6167 -- so they are also always valid (in particular, the unused bits can be
6168 -- random rubbish without affecting the validity of the array value).
6170 if not Is_Scalar_Type
(Typ
) or else Is_Packed_Array_Impl_Type
(Typ
) then
6173 -- If no validity checking, then everything is considered valid
6175 elsif not Validity_Checks_On
then
6178 -- Floating-point types are considered valid unless floating-point
6179 -- validity checks have been specifically turned on.
6181 elsif Is_Floating_Point_Type
(Typ
)
6182 and then not Validity_Check_Floating_Point
6186 -- If the expression is the value of an object that is known to be
6187 -- valid, then clearly the expression value itself is valid.
6189 elsif Is_Entity_Name
(Expr
)
6190 and then Is_Known_Valid
(Entity
(Expr
))
6192 -- Exclude volatile variables
6194 and then not Treat_As_Volatile
(Entity
(Expr
))
6198 -- References to discriminants are always considered valid. The value
6199 -- of a discriminant gets checked when the object is built. Within the
6200 -- record, we consider it valid, and it is important to do so, since
6201 -- otherwise we can try to generate bogus validity checks which
6202 -- reference discriminants out of scope. Discriminants of concurrent
6203 -- types are excluded for the same reason.
6205 elsif Is_Entity_Name
(Expr
)
6206 and then Denotes_Discriminant
(Expr
, Check_Concurrent
=> True)
6210 -- If the type is one for which all values are known valid, then we are
6211 -- sure that the value is valid except in the slightly odd case where
6212 -- the expression is a reference to a variable whose size has been
6213 -- explicitly set to a value greater than the object size.
6215 elsif Is_Known_Valid
(Typ
) then
6216 if Is_Entity_Name
(Expr
)
6217 and then Ekind
(Entity
(Expr
)) = E_Variable
6218 and then Esize
(Entity
(Expr
)) > Esize
(Typ
)
6225 -- Integer and character literals always have valid values, where
6226 -- appropriate these will be range checked in any case.
6228 elsif Nkind_In
(Expr
, N_Integer_Literal
, N_Character_Literal
) then
6231 -- If we have a type conversion or a qualification of a known valid
6232 -- value, then the result will always be valid.
6234 elsif Nkind_In
(Expr
, N_Type_Conversion
, N_Qualified_Expression
) then
6235 return Expr_Known_Valid
(Expression
(Expr
));
6237 -- Case of expression is a non-floating-point operator. In this case we
6238 -- can assume the result is valid the generated code for the operator
6239 -- will include whatever checks are needed (e.g. range checks) to ensure
6240 -- validity. This assumption does not hold for the floating-point case,
6241 -- since floating-point operators can generate Infinite or NaN results
6242 -- which are considered invalid.
6244 -- Historical note: in older versions, the exemption of floating-point
6245 -- types from this assumption was done only in cases where the parent
6246 -- was an assignment, function call or parameter association. Presumably
6247 -- the idea was that in other contexts, the result would be checked
6248 -- elsewhere, but this list of cases was missing tests (at least the
6249 -- N_Object_Declaration case, as shown by a reported missing validity
6250 -- check), and it is not clear why function calls but not procedure
6251 -- calls were tested for. It really seems more accurate and much
6252 -- safer to recognize that expressions which are the result of a
6253 -- floating-point operator can never be assumed to be valid.
6255 elsif Nkind
(Expr
) in N_Op
and then not Is_Floating_Point_Type
(Typ
) then
6258 -- The result of a membership test is always valid, since it is true or
6259 -- false, there are no other possibilities.
6261 elsif Nkind
(Expr
) in N_Membership_Test
then
6264 -- For all other cases, we do not know the expression is valid
6269 end Expr_Known_Valid
;
6275 procedure Find_Check
6277 Check_Type
: Character;
6278 Target_Type
: Entity_Id
;
6279 Entry_OK
: out Boolean;
6280 Check_Num
: out Nat
;
6281 Ent
: out Entity_Id
;
6284 function Within_Range_Of
6285 (Target_Type
: Entity_Id
;
6286 Check_Type
: Entity_Id
) return Boolean;
6287 -- Given a requirement for checking a range against Target_Type, and
6288 -- and a range Check_Type against which a check has already been made,
6289 -- determines if the check against check type is sufficient to ensure
6290 -- that no check against Target_Type is required.
6292 ---------------------
6293 -- Within_Range_Of --
6294 ---------------------
6296 function Within_Range_Of
6297 (Target_Type
: Entity_Id
;
6298 Check_Type
: Entity_Id
) return Boolean
6301 if Target_Type
= Check_Type
then
6306 Tlo
: constant Node_Id
:= Type_Low_Bound
(Target_Type
);
6307 Thi
: constant Node_Id
:= Type_High_Bound
(Target_Type
);
6308 Clo
: constant Node_Id
:= Type_Low_Bound
(Check_Type
);
6309 Chi
: constant Node_Id
:= Type_High_Bound
(Check_Type
);
6313 or else (Compile_Time_Known_Value
(Tlo
)
6315 Compile_Time_Known_Value
(Clo
)
6317 Expr_Value
(Clo
) >= Expr_Value
(Tlo
)))
6320 or else (Compile_Time_Known_Value
(Thi
)
6322 Compile_Time_Known_Value
(Chi
)
6324 Expr_Value
(Chi
) <= Expr_Value
(Clo
)))
6332 end Within_Range_Of
;
6334 -- Start of processing for Find_Check
6337 -- Establish default, in case no entry is found
6341 -- Case of expression is simple entity reference
6343 if Is_Entity_Name
(Expr
) then
6344 Ent
:= Entity
(Expr
);
6347 -- Case of expression is entity + known constant
6349 elsif Nkind
(Expr
) = N_Op_Add
6350 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
6351 and then Is_Entity_Name
(Left_Opnd
(Expr
))
6353 Ent
:= Entity
(Left_Opnd
(Expr
));
6354 Ofs
:= Expr_Value
(Right_Opnd
(Expr
));
6356 -- Case of expression is entity - known constant
6358 elsif Nkind
(Expr
) = N_Op_Subtract
6359 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
6360 and then Is_Entity_Name
(Left_Opnd
(Expr
))
6362 Ent
:= Entity
(Left_Opnd
(Expr
));
6363 Ofs
:= UI_Negate
(Expr_Value
(Right_Opnd
(Expr
)));
6365 -- Any other expression is not of the right form
6374 -- Come here with expression of appropriate form, check if entity is an
6375 -- appropriate one for our purposes.
6377 if (Ekind
(Ent
) = E_Variable
6378 or else Is_Constant_Object
(Ent
))
6379 and then not Is_Library_Level_Entity
(Ent
)
6387 -- See if there is matching check already
6389 for J
in reverse 1 .. Num_Saved_Checks
loop
6391 SC
: Saved_Check
renames Saved_Checks
(J
);
6393 if SC
.Killed
= False
6394 and then SC
.Entity
= Ent
6395 and then SC
.Offset
= Ofs
6396 and then SC
.Check_Type
= Check_Type
6397 and then Within_Range_Of
(Target_Type
, SC
.Target_Type
)
6405 -- If we fall through entry was not found
6410 ---------------------------------
6411 -- Generate_Discriminant_Check --
6412 ---------------------------------
6414 -- Note: the code for this procedure is derived from the
6415 -- Emit_Discriminant_Check Routine in trans.c.
6417 procedure Generate_Discriminant_Check
(N
: Node_Id
) is
6418 Loc
: constant Source_Ptr
:= Sloc
(N
);
6419 Pref
: constant Node_Id
:= Prefix
(N
);
6420 Sel
: constant Node_Id
:= Selector_Name
(N
);
6422 Orig_Comp
: constant Entity_Id
:=
6423 Original_Record_Component
(Entity
(Sel
));
6424 -- The original component to be checked
6426 Discr_Fct
: constant Entity_Id
:=
6427 Discriminant_Checking_Func
(Orig_Comp
);
6428 -- The discriminant checking function
6431 -- One discriminant to be checked in the type
6433 Real_Discr
: Entity_Id
;
6434 -- Actual discriminant in the call
6436 Pref_Type
: Entity_Id
;
6437 -- Type of relevant prefix (ignoring private/access stuff)
6440 -- List of arguments for function call
6443 -- Keep track of the formal corresponding to the actual we build for
6444 -- each discriminant, in order to be able to perform the necessary type
6448 -- Selected component reference for checking function argument
6451 Pref_Type
:= Etype
(Pref
);
6453 -- Force evaluation of the prefix, so that it does not get evaluated
6454 -- twice (once for the check, once for the actual reference). Such a
6455 -- double evaluation is always a potential source of inefficiency, and
6456 -- is functionally incorrect in the volatile case, or when the prefix
6457 -- may have side effects. A nonvolatile entity or a component of a
6458 -- nonvolatile entity requires no evaluation.
6460 if Is_Entity_Name
(Pref
) then
6461 if Treat_As_Volatile
(Entity
(Pref
)) then
6462 Force_Evaluation
(Pref
, Name_Req
=> True);
6465 elsif Treat_As_Volatile
(Etype
(Pref
)) then
6466 Force_Evaluation
(Pref
, Name_Req
=> True);
6468 elsif Nkind
(Pref
) = N_Selected_Component
6469 and then Is_Entity_Name
(Prefix
(Pref
))
6474 Force_Evaluation
(Pref
, Name_Req
=> True);
6477 -- For a tagged type, use the scope of the original component to
6478 -- obtain the type, because ???
6480 if Is_Tagged_Type
(Scope
(Orig_Comp
)) then
6481 Pref_Type
:= Scope
(Orig_Comp
);
6483 -- For an untagged derived type, use the discriminants of the parent
6484 -- which have been renamed in the derivation, possibly by a one-to-many
6485 -- discriminant constraint. For untagged type, initially get the Etype
6489 if Is_Derived_Type
(Pref_Type
)
6490 and then Number_Discriminants
(Pref_Type
) /=
6491 Number_Discriminants
(Etype
(Base_Type
(Pref_Type
)))
6493 Pref_Type
:= Etype
(Base_Type
(Pref_Type
));
6497 -- We definitely should have a checking function, This routine should
6498 -- not be called if no discriminant checking function is present.
6500 pragma Assert
(Present
(Discr_Fct
));
6502 -- Create the list of the actual parameters for the call. This list
6503 -- is the list of the discriminant fields of the record expression to
6504 -- be discriminant checked.
6507 Formal
:= First_Formal
(Discr_Fct
);
6508 Discr
:= First_Discriminant
(Pref_Type
);
6509 while Present
(Discr
) loop
6511 -- If we have a corresponding discriminant field, and a parent
6512 -- subtype is present, then we want to use the corresponding
6513 -- discriminant since this is the one with the useful value.
6515 if Present
(Corresponding_Discriminant
(Discr
))
6516 and then Ekind
(Pref_Type
) = E_Record_Type
6517 and then Present
(Parent_Subtype
(Pref_Type
))
6519 Real_Discr
:= Corresponding_Discriminant
(Discr
);
6521 Real_Discr
:= Discr
;
6524 -- Construct the reference to the discriminant
6527 Make_Selected_Component
(Loc
,
6529 Unchecked_Convert_To
(Pref_Type
,
6530 Duplicate_Subexpr
(Pref
)),
6531 Selector_Name
=> New_Occurrence_Of
(Real_Discr
, Loc
));
6533 -- Manually analyze and resolve this selected component. We really
6534 -- want it just as it appears above, and do not want the expander
6535 -- playing discriminal games etc with this reference. Then we append
6536 -- the argument to the list we are gathering.
6538 Set_Etype
(Scomp
, Etype
(Real_Discr
));
6539 Set_Analyzed
(Scomp
, True);
6540 Append_To
(Args
, Convert_To
(Etype
(Formal
), Scomp
));
6542 Next_Formal_With_Extras
(Formal
);
6543 Next_Discriminant
(Discr
);
6546 -- Now build and insert the call
6549 Make_Raise_Constraint_Error
(Loc
,
6551 Make_Function_Call
(Loc
,
6552 Name
=> New_Occurrence_Of
(Discr_Fct
, Loc
),
6553 Parameter_Associations
=> Args
),
6554 Reason
=> CE_Discriminant_Check_Failed
));
6555 end Generate_Discriminant_Check
;
6557 ---------------------------
6558 -- Generate_Index_Checks --
6559 ---------------------------
6561 procedure Generate_Index_Checks
(N
: Node_Id
) is
6563 function Entity_Of_Prefix
return Entity_Id
;
6564 -- Returns the entity of the prefix of N (or Empty if not found)
6566 ----------------------
6567 -- Entity_Of_Prefix --
6568 ----------------------
6570 function Entity_Of_Prefix
return Entity_Id
is
6575 while not Is_Entity_Name
(P
) loop
6576 if not Nkind_In
(P
, N_Selected_Component
,
6577 N_Indexed_Component
)
6586 end Entity_Of_Prefix
;
6590 Loc
: constant Source_Ptr
:= Sloc
(N
);
6591 A
: constant Node_Id
:= Prefix
(N
);
6592 A_Ent
: constant Entity_Id
:= Entity_Of_Prefix
;
6595 -- Start of processing for Generate_Index_Checks
6598 -- Ignore call if the prefix is not an array since we have a serious
6599 -- error in the sources. Ignore it also if index checks are suppressed
6600 -- for array object or type.
6602 if not Is_Array_Type
(Etype
(A
))
6603 or else (Present
(A_Ent
) and then Index_Checks_Suppressed
(A_Ent
))
6604 or else Index_Checks_Suppressed
(Etype
(A
))
6608 -- The indexed component we are dealing with contains 'Loop_Entry in its
6609 -- prefix. This case arises when analysis has determined that constructs
6612 -- Prefix'Loop_Entry (Expr)
6613 -- Prefix'Loop_Entry (Expr1, Expr2, ... ExprN)
6615 -- require rewriting for error detection purposes. A side effect of this
6616 -- action is the generation of index checks that mention 'Loop_Entry.
6617 -- Delay the generation of the check until 'Loop_Entry has been properly
6618 -- expanded. This is done in Expand_Loop_Entry_Attributes.
6620 elsif Nkind
(Prefix
(N
)) = N_Attribute_Reference
6621 and then Attribute_Name
(Prefix
(N
)) = Name_Loop_Entry
6626 -- Generate a raise of constraint error with the appropriate reason and
6627 -- a condition of the form:
6629 -- Base_Type (Sub) not in Array'Range (Subscript)
6631 -- Note that the reason we generate the conversion to the base type here
6632 -- is that we definitely want the range check to take place, even if it
6633 -- looks like the subtype is OK. Optimization considerations that allow
6634 -- us to omit the check have already been taken into account in the
6635 -- setting of the Do_Range_Check flag earlier on.
6637 Sub
:= First
(Expressions
(N
));
6639 -- Handle string literals
6641 if Ekind
(Etype
(A
)) = E_String_Literal_Subtype
then
6642 if Do_Range_Check
(Sub
) then
6643 Set_Do_Range_Check
(Sub
, False);
6645 -- For string literals we obtain the bounds of the string from the
6646 -- associated subtype.
6649 Make_Raise_Constraint_Error
(Loc
,
6653 Convert_To
(Base_Type
(Etype
(Sub
)),
6654 Duplicate_Subexpr_Move_Checks
(Sub
)),
6656 Make_Attribute_Reference
(Loc
,
6657 Prefix
=> New_Occurrence_Of
(Etype
(A
), Loc
),
6658 Attribute_Name
=> Name_Range
)),
6659 Reason
=> CE_Index_Check_Failed
));
6666 A_Idx
: Node_Id
:= Empty
;
6673 A_Idx
:= First_Index
(Etype
(A
));
6675 while Present
(Sub
) loop
6676 if Do_Range_Check
(Sub
) then
6677 Set_Do_Range_Check
(Sub
, False);
6679 -- Force evaluation except for the case of a simple name of
6680 -- a nonvolatile entity.
6682 if not Is_Entity_Name
(Sub
)
6683 or else Treat_As_Volatile
(Entity
(Sub
))
6685 Force_Evaluation
(Sub
);
6688 if Nkind
(A_Idx
) = N_Range
then
6691 elsif Nkind
(A_Idx
) = N_Identifier
6692 or else Nkind
(A_Idx
) = N_Expanded_Name
6694 A_Range
:= Scalar_Range
(Entity
(A_Idx
));
6696 else pragma Assert
(Nkind
(A_Idx
) = N_Subtype_Indication
);
6697 A_Range
:= Range_Expression
(Constraint
(A_Idx
));
6700 -- For array objects with constant bounds we can generate
6701 -- the index check using the bounds of the type of the index
6704 and then Ekind
(A_Ent
) = E_Variable
6705 and then Is_Constant_Bound
(Low_Bound
(A_Range
))
6706 and then Is_Constant_Bound
(High_Bound
(A_Range
))
6709 Make_Attribute_Reference
(Loc
,
6711 New_Occurrence_Of
(Etype
(A_Idx
), Loc
),
6712 Attribute_Name
=> Name_Range
);
6714 -- For arrays with non-constant bounds we cannot generate
6715 -- the index check using the bounds of the type of the index
6716 -- since it may reference discriminants of some enclosing
6717 -- type. We obtain the bounds directly from the prefix
6724 Num
:= New_List
(Make_Integer_Literal
(Loc
, Ind
));
6728 Make_Attribute_Reference
(Loc
,
6730 Duplicate_Subexpr_Move_Checks
(A
, Name_Req
=> True),
6731 Attribute_Name
=> Name_Range
,
6732 Expressions
=> Num
);
6736 Make_Raise_Constraint_Error
(Loc
,
6740 Convert_To
(Base_Type
(Etype
(Sub
)),
6741 Duplicate_Subexpr_Move_Checks
(Sub
)),
6742 Right_Opnd
=> Range_N
),
6743 Reason
=> CE_Index_Check_Failed
));
6746 A_Idx
:= Next_Index
(A_Idx
);
6752 end Generate_Index_Checks
;
6754 --------------------------
6755 -- Generate_Range_Check --
6756 --------------------------
6758 procedure Generate_Range_Check
6760 Target_Type
: Entity_Id
;
6761 Reason
: RT_Exception_Code
)
6763 Loc
: constant Source_Ptr
:= Sloc
(N
);
6764 Source_Type
: constant Entity_Id
:= Etype
(N
);
6765 Source_Base_Type
: constant Entity_Id
:= Base_Type
(Source_Type
);
6766 Target_Base_Type
: constant Entity_Id
:= Base_Type
(Target_Type
);
6768 procedure Convert_And_Check_Range
;
6769 -- Convert the conversion operand to the target base type and save in
6770 -- a temporary. Then check the converted value against the range of the
6773 -----------------------------
6774 -- Convert_And_Check_Range --
6775 -----------------------------
6777 procedure Convert_And_Check_Range
is
6778 Tnn
: constant Entity_Id
:= Make_Temporary
(Loc
, 'T', N
);
6779 Conv_Node
: Node_Id
;
6782 -- For enumeration types with non-standard representation this is a
6783 -- direct conversion from the enumeration type to the target integer
6784 -- type, which is treated by the back end as a normal integer type
6785 -- conversion, treating the enumeration type as an integer, which is
6786 -- exactly what we want. We set Conversion_OK to make sure that the
6787 -- analyzer does not complain about what otherwise might be an
6788 -- illegal conversion.
6790 if Is_Enumeration_Type
(Source_Base_Type
)
6791 and then Present
(Enum_Pos_To_Rep
(Source_Base_Type
))
6792 and then Is_Integer_Type
(Target_Base_Type
)
6796 (Typ
=> Target_Base_Type
,
6797 Expr
=> Duplicate_Subexpr
(N
));
6803 Make_Type_Conversion
(Loc
,
6804 Subtype_Mark
=> New_Occurrence_Of
(Target_Base_Type
, Loc
),
6805 Expression
=> Duplicate_Subexpr
(N
));
6808 -- We make a temporary to hold the value of the converted value
6809 -- (converted to the base type), and then do the test against this
6810 -- temporary. The conversion itself is replaced by an occurrence of
6811 -- Tnn and followed by the explicit range check. Note that checks
6812 -- are suppressed for this code, since we don't want a recursive
6813 -- range check popping up.
6815 -- Tnn : constant Target_Base_Type := Target_Base_Type (N);
6816 -- [constraint_error when Tnn not in Target_Type]
6818 Insert_Actions
(N
, New_List
(
6819 Make_Object_Declaration
(Loc
,
6820 Defining_Identifier
=> Tnn
,
6821 Object_Definition
=> New_Occurrence_Of
(Target_Base_Type
, Loc
),
6822 Constant_Present
=> True,
6823 Expression
=> Conv_Node
),
6825 Make_Raise_Constraint_Error
(Loc
,
6828 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
6829 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
6831 Suppress
=> All_Checks
);
6833 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
6835 -- Set the type of N, because the declaration for Tnn might not
6836 -- be analyzed yet, as is the case if N appears within a record
6837 -- declaration, as a discriminant constraint or expression.
6839 Set_Etype
(N
, Target_Base_Type
);
6840 end Convert_And_Check_Range
;
6842 -- Start of processing for Generate_Range_Check
6845 -- First special case, if the source type is already within the range
6846 -- of the target type, then no check is needed (probably we should have
6847 -- stopped Do_Range_Check from being set in the first place, but better
6848 -- late than never in preventing junk code and junk flag settings.
6850 if In_Subrange_Of
(Source_Type
, Target_Type
)
6852 -- We do NOT apply this if the source node is a literal, since in this
6853 -- case the literal has already been labeled as having the subtype of
6857 (Nkind_In
(N
, N_Integer_Literal
, N_Real_Literal
, N_Character_Literal
)
6860 and then Ekind
(Entity
(N
)) = E_Enumeration_Literal
))
6862 Set_Do_Range_Check
(N
, False);
6866 -- Here a check is needed. If the expander is not active, or if we are
6867 -- in GNATProve mode, then simply set the Do_Range_Check flag and we
6868 -- are done. In both these cases, we just want to see the range check
6869 -- flag set, we do not want to generate the explicit range check code.
6871 if GNATprove_Mode
or else not Expander_Active
then
6872 Set_Do_Range_Check
(N
, True);
6876 -- Here we will generate an explicit range check, so we don't want to
6877 -- set the Do_Range check flag, since the range check is taken care of
6878 -- by the code we will generate.
6880 Set_Do_Range_Check
(N
, False);
6882 -- Force evaluation of the node, so that it does not get evaluated twice
6883 -- (once for the check, once for the actual reference). Such a double
6884 -- evaluation is always a potential source of inefficiency, and is
6885 -- functionally incorrect in the volatile case.
6887 -- We skip the evaluation of attribute references because, after these
6888 -- runtime checks are generated, the expander may need to rewrite this
6889 -- node (for example, see Attribute_Max_Size_In_Storage_Elements in
6890 -- Expand_N_Attribute_Reference).
6892 if Nkind
(N
) /= N_Attribute_Reference
6893 and then (not Is_Entity_Name
(N
)
6894 or else Treat_As_Volatile
(Entity
(N
)))
6896 Force_Evaluation
(N
, Mode
=> Strict
);
6899 -- The easiest case is when Source_Base_Type and Target_Base_Type are
6900 -- the same since in this case we can simply do a direct check of the
6901 -- value of N against the bounds of Target_Type.
6903 -- [constraint_error when N not in Target_Type]
6905 -- Note: this is by far the most common case, for example all cases of
6906 -- checks on the RHS of assignments are in this category, but not all
6907 -- cases are like this. Notably conversions can involve two types.
6909 if Source_Base_Type
= Target_Base_Type
then
6911 -- Insert the explicit range check. Note that we suppress checks for
6912 -- this code, since we don't want a recursive range check popping up.
6915 Make_Raise_Constraint_Error
(Loc
,
6918 Left_Opnd
=> Duplicate_Subexpr
(N
),
6919 Right_Opnd
=> New_Occurrence_Of
(Target_Type
, Loc
)),
6921 Suppress
=> All_Checks
);
6923 -- Next test for the case where the target type is within the bounds
6924 -- of the base type of the source type, since in this case we can
6925 -- simply convert these bounds to the base type of T to do the test.
6927 -- [constraint_error when N not in
6928 -- Source_Base_Type (Target_Type'First)
6930 -- Source_Base_Type(Target_Type'Last))]
6932 -- The conversions will always work and need no check
6934 -- Unchecked_Convert_To is used instead of Convert_To to handle the case
6935 -- of converting from an enumeration value to an integer type, such as
6936 -- occurs for the case of generating a range check on Enum'Val(Exp)
6937 -- (which used to be handled by gigi). This is OK, since the conversion
6938 -- itself does not require a check.
6940 elsif In_Subrange_Of
(Target_Type
, Source_Base_Type
) then
6942 -- Insert the explicit range check. Note that we suppress checks for
6943 -- this code, since we don't want a recursive range check popping up.
6945 if Is_Discrete_Type
(Source_Base_Type
)
6947 Is_Discrete_Type
(Target_Base_Type
)
6950 Make_Raise_Constraint_Error
(Loc
,
6953 Left_Opnd
=> Duplicate_Subexpr
(N
),
6958 Unchecked_Convert_To
(Source_Base_Type
,
6959 Make_Attribute_Reference
(Loc
,
6961 New_Occurrence_Of
(Target_Type
, Loc
),
6962 Attribute_Name
=> Name_First
)),
6965 Unchecked_Convert_To
(Source_Base_Type
,
6966 Make_Attribute_Reference
(Loc
,
6968 New_Occurrence_Of
(Target_Type
, Loc
),
6969 Attribute_Name
=> Name_Last
)))),
6971 Suppress
=> All_Checks
);
6973 -- For conversions involving at least one type that is not discrete,
6974 -- first convert to target type and then generate the range check.
6975 -- This avoids problems with values that are close to a bound of the
6976 -- target type that would fail a range check when done in a larger
6977 -- source type before converting but would pass if converted with
6978 -- rounding and then checked (such as in float-to-float conversions).
6981 Convert_And_Check_Range
;
6984 -- Note that at this stage we now that the Target_Base_Type is not in
6985 -- the range of the Source_Base_Type (since even the Target_Type itself
6986 -- is not in this range). It could still be the case that Source_Type is
6987 -- in range of the target base type since we have not checked that case.
6989 -- If that is the case, we can freely convert the source to the target,
6990 -- and then test the target result against the bounds.
6992 elsif In_Subrange_Of
(Source_Type
, Target_Base_Type
) then
6993 Convert_And_Check_Range
;
6995 -- At this stage, we know that we have two scalar types, which are
6996 -- directly convertible, and where neither scalar type has a base
6997 -- range that is in the range of the other scalar type.
6999 -- The only way this can happen is with a signed and unsigned type.
7000 -- So test for these two cases:
7003 -- Case of the source is unsigned and the target is signed
7005 if Is_Unsigned_Type
(Source_Base_Type
)
7006 and then not Is_Unsigned_Type
(Target_Base_Type
)
7008 -- If the source is unsigned and the target is signed, then we
7009 -- know that the source is not shorter than the target (otherwise
7010 -- the source base type would be in the target base type range).
7012 -- In other words, the unsigned type is either the same size as
7013 -- the target, or it is larger. It cannot be smaller.
7016 (Esize
(Source_Base_Type
) >= Esize
(Target_Base_Type
));
7018 -- We only need to check the low bound if the low bound of the
7019 -- target type is non-negative. If the low bound of the target
7020 -- type is negative, then we know that we will fit fine.
7022 -- If the high bound of the target type is negative, then we
7023 -- know we have a constraint error, since we can't possibly
7024 -- have a negative source.
7026 -- With these two checks out of the way, we can do the check
7027 -- using the source type safely
7029 -- This is definitely the most annoying case.
7031 -- [constraint_error
7032 -- when (Target_Type'First >= 0
7034 -- N < Source_Base_Type (Target_Type'First))
7035 -- or else Target_Type'Last < 0
7036 -- or else N > Source_Base_Type (Target_Type'Last)];
7038 -- We turn off all checks since we know that the conversions
7039 -- will work fine, given the guards for negative values.
7042 Make_Raise_Constraint_Error
(Loc
,
7048 Left_Opnd
=> Make_Op_Ge
(Loc
,
7050 Make_Attribute_Reference
(Loc
,
7052 New_Occurrence_Of
(Target_Type
, Loc
),
7053 Attribute_Name
=> Name_First
),
7054 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
7058 Left_Opnd
=> Duplicate_Subexpr
(N
),
7060 Convert_To
(Source_Base_Type
,
7061 Make_Attribute_Reference
(Loc
,
7063 New_Occurrence_Of
(Target_Type
, Loc
),
7064 Attribute_Name
=> Name_First
)))),
7069 Make_Attribute_Reference
(Loc
,
7070 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
7071 Attribute_Name
=> Name_Last
),
7072 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
))),
7076 Left_Opnd
=> Duplicate_Subexpr
(N
),
7078 Convert_To
(Source_Base_Type
,
7079 Make_Attribute_Reference
(Loc
,
7080 Prefix
=> New_Occurrence_Of
(Target_Type
, Loc
),
7081 Attribute_Name
=> Name_Last
)))),
7084 Suppress
=> All_Checks
);
7086 -- Only remaining possibility is that the source is signed and
7087 -- the target is unsigned.
7090 pragma Assert
(not Is_Unsigned_Type
(Source_Base_Type
)
7091 and then Is_Unsigned_Type
(Target_Base_Type
));
7093 -- If the source is signed and the target is unsigned, then we
7094 -- know that the target is not shorter than the source (otherwise
7095 -- the target base type would be in the source base type range).
7097 -- In other words, the unsigned type is either the same size as
7098 -- the target, or it is larger. It cannot be smaller.
7100 -- Clearly we have an error if the source value is negative since
7101 -- no unsigned type can have negative values. If the source type
7102 -- is non-negative, then the check can be done using the target
7105 -- Tnn : constant Target_Base_Type (N) := Target_Type;
7107 -- [constraint_error
7108 -- when N < 0 or else Tnn not in Target_Type];
7110 -- We turn off all checks for the conversion of N to the target
7111 -- base type, since we generate the explicit check to ensure that
7112 -- the value is non-negative
7115 Tnn
: constant Entity_Id
:= Make_Temporary
(Loc
, 'T', N
);
7118 Insert_Actions
(N
, New_List
(
7119 Make_Object_Declaration
(Loc
,
7120 Defining_Identifier
=> Tnn
,
7121 Object_Definition
=>
7122 New_Occurrence_Of
(Target_Base_Type
, Loc
),
7123 Constant_Present
=> True,
7125 Make_Unchecked_Type_Conversion
(Loc
,
7127 New_Occurrence_Of
(Target_Base_Type
, Loc
),
7128 Expression
=> Duplicate_Subexpr
(N
))),
7130 Make_Raise_Constraint_Error
(Loc
,
7135 Left_Opnd
=> Duplicate_Subexpr
(N
),
7136 Right_Opnd
=> Make_Integer_Literal
(Loc
, Uint_0
)),
7140 Left_Opnd
=> New_Occurrence_Of
(Tnn
, Loc
),
7142 New_Occurrence_Of
(Target_Type
, Loc
))),
7145 Suppress
=> All_Checks
);
7147 -- Set the Etype explicitly, because Insert_Actions may have
7148 -- placed the declaration in the freeze list for an enclosing
7149 -- construct, and thus it is not analyzed yet.
7151 Set_Etype
(Tnn
, Target_Base_Type
);
7152 Rewrite
(N
, New_Occurrence_Of
(Tnn
, Loc
));
7156 end Generate_Range_Check
;
7162 function Get_Check_Id
(N
: Name_Id
) return Check_Id
is
7164 -- For standard check name, we can do a direct computation
7166 if N
in First_Check_Name
.. Last_Check_Name
then
7167 return Check_Id
(N
- (First_Check_Name
- 1));
7169 -- For non-standard names added by pragma Check_Name, search table
7172 for J
in All_Checks
+ 1 .. Check_Names
.Last
loop
7173 if Check_Names
.Table
(J
) = N
then
7179 -- No matching name found
7184 ---------------------
7185 -- Get_Discriminal --
7186 ---------------------
7188 function Get_Discriminal
(E
: Entity_Id
; Bound
: Node_Id
) return Node_Id
is
7189 Loc
: constant Source_Ptr
:= Sloc
(E
);
7194 -- The bound can be a bona fide parameter of a protected operation,
7195 -- rather than a prival encoded as an in-parameter.
7197 if No
(Discriminal_Link
(Entity
(Bound
))) then
7201 -- Climb the scope stack looking for an enclosing protected type. If
7202 -- we run out of scopes, return the bound itself.
7205 while Present
(Sc
) loop
7206 if Sc
= Standard_Standard
then
7208 elsif Ekind
(Sc
) = E_Protected_Type
then
7215 D
:= First_Discriminant
(Sc
);
7216 while Present
(D
) loop
7217 if Chars
(D
) = Chars
(Bound
) then
7218 return New_Occurrence_Of
(Discriminal
(D
), Loc
);
7221 Next_Discriminant
(D
);
7225 end Get_Discriminal
;
7227 ----------------------
7228 -- Get_Range_Checks --
7229 ----------------------
7231 function Get_Range_Checks
7233 Target_Typ
: Entity_Id
;
7234 Source_Typ
: Entity_Id
:= Empty
;
7235 Warn_Node
: Node_Id
:= Empty
) return Check_Result
7239 Selected_Range_Checks
(Ck_Node
, Target_Typ
, Source_Typ
, Warn_Node
);
7240 end Get_Range_Checks
;
7246 function Guard_Access
7249 Ck_Node
: Node_Id
) return Node_Id
7252 if Nkind
(Cond
) = N_Or_Else
then
7253 Set_Paren_Count
(Cond
, 1);
7256 if Nkind
(Ck_Node
) = N_Allocator
then
7264 Left_Opnd
=> Duplicate_Subexpr_No_Checks
(Ck_Node
),
7265 Right_Opnd
=> Make_Null
(Loc
)),
7266 Right_Opnd
=> Cond
);
7270 -----------------------------
7271 -- Index_Checks_Suppressed --
7272 -----------------------------
7274 function Index_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
7276 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
7277 return Is_Check_Suppressed
(E
, Index_Check
);
7279 return Scope_Suppress
.Suppress
(Index_Check
);
7281 end Index_Checks_Suppressed
;
7287 procedure Initialize
is
7289 for J
in Determine_Range_Cache_N
'Range loop
7290 Determine_Range_Cache_N
(J
) := Empty
;
7295 for J
in Int
range 1 .. All_Checks
loop
7296 Check_Names
.Append
(Name_Id
(Int
(First_Check_Name
) + J
- 1));
7300 -------------------------
7301 -- Insert_Range_Checks --
7302 -------------------------
7304 procedure Insert_Range_Checks
7305 (Checks
: Check_Result
;
7307 Suppress_Typ
: Entity_Id
;
7308 Static_Sloc
: Source_Ptr
:= No_Location
;
7309 Flag_Node
: Node_Id
:= Empty
;
7310 Do_Before
: Boolean := False)
7312 Checks_On
: constant Boolean :=
7313 not Index_Checks_Suppressed
(Suppress_Typ
)
7315 not Range_Checks_Suppressed
(Suppress_Typ
);
7317 Check_Node
: Node_Id
;
7318 Internal_Flag_Node
: Node_Id
:= Flag_Node
;
7319 Internal_Static_Sloc
: Source_Ptr
:= Static_Sloc
;
7322 -- For now we just return if Checks_On is false, however this should be
7323 -- enhanced to check for an always True value in the condition and to
7324 -- generate a compilation warning???
7326 if not Expander_Active
or not Checks_On
then
7330 if Static_Sloc
= No_Location
then
7331 Internal_Static_Sloc
:= Sloc
(Node
);
7334 if No
(Flag_Node
) then
7335 Internal_Flag_Node
:= Node
;
7338 for J
in 1 .. 2 loop
7339 exit when No
(Checks
(J
));
7341 if Nkind
(Checks
(J
)) = N_Raise_Constraint_Error
7342 and then Present
(Condition
(Checks
(J
)))
7344 if not Has_Dynamic_Range_Check
(Internal_Flag_Node
) then
7345 Check_Node
:= Checks
(J
);
7346 Mark_Rewrite_Insertion
(Check_Node
);
7349 Insert_Before_And_Analyze
(Node
, Check_Node
);
7351 Insert_After_And_Analyze
(Node
, Check_Node
);
7354 Set_Has_Dynamic_Range_Check
(Internal_Flag_Node
);
7359 Make_Raise_Constraint_Error
(Internal_Static_Sloc
,
7360 Reason
=> CE_Range_Check_Failed
);
7361 Mark_Rewrite_Insertion
(Check_Node
);
7364 Insert_Before_And_Analyze
(Node
, Check_Node
);
7366 Insert_After_And_Analyze
(Node
, Check_Node
);
7370 end Insert_Range_Checks
;
7372 ------------------------
7373 -- Insert_Valid_Check --
7374 ------------------------
7376 procedure Insert_Valid_Check
7378 Related_Id
: Entity_Id
:= Empty
;
7379 Is_Low_Bound
: Boolean := False;
7380 Is_High_Bound
: Boolean := False)
7382 Loc
: constant Source_Ptr
:= Sloc
(Expr
);
7383 Typ
: constant Entity_Id
:= Etype
(Expr
);
7387 -- Do not insert if checks off, or if not checking validity or if
7388 -- expression is known to be valid.
7390 if not Validity_Checks_On
7391 or else Range_Or_Validity_Checks_Suppressed
(Expr
)
7392 or else Expr_Known_Valid
(Expr
)
7396 -- Do not insert checks within a predicate function. This will arise
7397 -- if the current unit and the predicate function are being compiled
7398 -- with validity checks enabled.
7400 elsif Present
(Predicate_Function
(Typ
))
7401 and then Current_Scope
= Predicate_Function
(Typ
)
7405 -- If the expression is a packed component of a modular type of the
7406 -- right size, the data is always valid.
7408 elsif Nkind
(Expr
) = N_Selected_Component
7409 and then Present
(Component_Clause
(Entity
(Selector_Name
(Expr
))))
7410 and then Is_Modular_Integer_Type
(Typ
)
7411 and then Modulus
(Typ
) = 2 ** Esize
(Entity
(Selector_Name
(Expr
)))
7415 -- Do not generate a validity check when inside a generic unit as this
7416 -- is an expansion activity.
7418 elsif Inside_A_Generic
then
7422 -- If we have a checked conversion, then validity check applies to
7423 -- the expression inside the conversion, not the result, since if
7424 -- the expression inside is valid, then so is the conversion result.
7427 while Nkind
(Exp
) = N_Type_Conversion
loop
7428 Exp
:= Expression
(Exp
);
7431 -- Do not generate a check for a variable which already validates the
7432 -- value of an assignable object.
7434 if Is_Validation_Variable_Reference
(Exp
) then
7444 -- If the expression denotes an assignable object, capture its value
7445 -- in a variable and replace the original expression by the variable.
7446 -- This approach has several effects:
7448 -- 1) The evaluation of the object results in only one read in the
7449 -- case where the object is atomic or volatile.
7451 -- Var ... := Object; -- read
7453 -- 2) The captured value is the one verified by attribute 'Valid.
7454 -- As a result the object is not evaluated again, which would
7455 -- result in an unwanted read in the case where the object is
7456 -- atomic or volatile.
7458 -- if not Var'Valid then -- OK, no read of Object
7460 -- if not Object'Valid then -- Wrong, extra read of Object
7462 -- 3) The captured value replaces the original object reference.
7463 -- As a result the object is not evaluated again, in the same
7466 -- ... Var ... -- OK, no read of Object
7468 -- ... Object ... -- Wrong, extra read of Object
7470 -- 4) The use of a variable to capture the value of the object
7471 -- allows the propagation of any changes back to the original
7474 -- procedure Call (Val : in out ...);
7476 -- Var : ... := Object; -- read Object
7477 -- if not Var'Valid then -- validity check
7478 -- Call (Var); -- modify Var
7479 -- Object := Var; -- update Object
7481 if Is_Variable
(Exp
) then
7482 Var_Id
:= Make_Temporary
(Loc
, 'T', Exp
);
7484 -- Because we could be dealing with a transient scope which would
7485 -- cause our object declaration to remain unanalyzed we must do
7486 -- some manual decoration.
7488 Set_Ekind
(Var_Id
, E_Variable
);
7489 Set_Etype
(Var_Id
, Typ
);
7492 Make_Object_Declaration
(Loc
,
7493 Defining_Identifier
=> Var_Id
,
7494 Object_Definition
=> New_Occurrence_Of
(Typ
, Loc
),
7495 Expression
=> New_Copy_Tree
(Exp
)),
7496 Suppress
=> Validity_Check
);
7498 Set_Validated_Object
(Var_Id
, New_Copy_Tree
(Exp
));
7499 Rewrite
(Exp
, New_Occurrence_Of
(Var_Id
, Loc
));
7500 PV
:= New_Occurrence_Of
(Var_Id
, Loc
);
7502 -- Copy the Do_Range_Check flag over to the new Exp, so it doesn't
7503 -- get lost. Floating point types are handled elsewhere.
7505 if not Is_Floating_Point_Type
(Typ
) then
7506 Set_Do_Range_Check
(Exp
, Do_Range_Check
(Original_Node
(Exp
)));
7509 -- Otherwise the expression does not denote a variable. Force its
7510 -- evaluation by capturing its value in a constant. Generate:
7512 -- Temp : constant ... := Exp;
7517 Related_Id
=> Related_Id
,
7518 Is_Low_Bound
=> Is_Low_Bound
,
7519 Is_High_Bound
=> Is_High_Bound
);
7521 PV
:= New_Copy_Tree
(Exp
);
7524 -- A rather specialized test. If PV is an analyzed expression which
7525 -- is an indexed component of a packed array that has not been
7526 -- properly expanded, turn off its Analyzed flag to make sure it
7527 -- gets properly reexpanded. If the prefix is an access value,
7528 -- the dereference will be added later.
7530 -- The reason this arises is that Duplicate_Subexpr_No_Checks did
7531 -- an analyze with the old parent pointer. This may point e.g. to
7532 -- a subprogram call, which deactivates this expansion.
7535 and then Nkind
(PV
) = N_Indexed_Component
7536 and then Is_Array_Type
(Etype
(Prefix
(PV
)))
7537 and then Present
(Packed_Array_Impl_Type
(Etype
(Prefix
(PV
))))
7539 Set_Analyzed
(PV
, False);
7542 -- Build the raise CE node to check for validity. We build a type
7543 -- qualification for the prefix, since it may not be of the form of
7544 -- a name, and we don't care in this context!
7547 Make_Raise_Constraint_Error
(Loc
,
7551 Make_Attribute_Reference
(Loc
,
7553 Attribute_Name
=> Name_Valid
)),
7554 Reason
=> CE_Invalid_Data
);
7556 -- Insert the validity check. Note that we do this with validity
7557 -- checks turned off, to avoid recursion, we do not want validity
7558 -- checks on the validity checking code itself.
7560 Insert_Action
(Expr
, CE
, Suppress
=> Validity_Check
);
7562 -- If the expression is a reference to an element of a bit-packed
7563 -- array, then it is rewritten as a renaming declaration. If the
7564 -- expression is an actual in a call, it has not been expanded,
7565 -- waiting for the proper point at which to do it. The same happens
7566 -- with renamings, so that we have to force the expansion now. This
7567 -- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb
7570 if Is_Entity_Name
(Exp
)
7571 and then Nkind
(Parent
(Entity
(Exp
))) =
7572 N_Object_Renaming_Declaration
7575 Old_Exp
: constant Node_Id
:= Name
(Parent
(Entity
(Exp
)));
7577 if Nkind
(Old_Exp
) = N_Indexed_Component
7578 and then Is_Bit_Packed_Array
(Etype
(Prefix
(Old_Exp
)))
7580 Expand_Packed_Element_Reference
(Old_Exp
);
7585 end Insert_Valid_Check
;
7587 -------------------------------------
7588 -- Is_Signed_Integer_Arithmetic_Op --
7589 -------------------------------------
7591 function Is_Signed_Integer_Arithmetic_Op
(N
: Node_Id
) return Boolean is
7605 return Is_Signed_Integer_Type
(Etype
(N
));
7607 when N_Case_Expression
7610 return Is_Signed_Integer_Type
(Etype
(N
));
7615 end Is_Signed_Integer_Arithmetic_Op
;
7617 ----------------------------------
7618 -- Install_Null_Excluding_Check --
7619 ----------------------------------
7621 procedure Install_Null_Excluding_Check
(N
: Node_Id
) is
7622 Loc
: constant Source_Ptr
:= Sloc
(Parent
(N
));
7623 Typ
: constant Entity_Id
:= Etype
(N
);
7625 function Safe_To_Capture_In_Parameter_Value
return Boolean;
7626 -- Determines if it is safe to capture Known_Non_Null status for an
7627 -- the entity referenced by node N. The caller ensures that N is indeed
7628 -- an entity name. It is safe to capture the non-null status for an IN
7629 -- parameter when the reference occurs within a declaration that is sure
7630 -- to be executed as part of the declarative region.
7632 procedure Mark_Non_Null
;
7633 -- After installation of check, if the node in question is an entity
7634 -- name, then mark this entity as non-null if possible.
7636 function Safe_To_Capture_In_Parameter_Value
return Boolean is
7637 E
: constant Entity_Id
:= Entity
(N
);
7638 S
: constant Entity_Id
:= Current_Scope
;
7642 if Ekind
(E
) /= E_In_Parameter
then
7646 -- Two initial context checks. We must be inside a subprogram body
7647 -- with declarations and reference must not appear in nested scopes.
7649 if (Ekind
(S
) /= E_Function
and then Ekind
(S
) /= E_Procedure
)
7650 or else Scope
(E
) /= S
7655 S_Par
:= Parent
(Parent
(S
));
7657 if Nkind
(S_Par
) /= N_Subprogram_Body
7658 or else No
(Declarations
(S_Par
))
7668 -- Retrieve the declaration node of N (if any). Note that N
7669 -- may be a part of a complex initialization expression.
7673 while Present
(P
) loop
7675 -- If we have a short circuit form, and we are within the right
7676 -- hand expression, we return false, since the right hand side
7677 -- is not guaranteed to be elaborated.
7679 if Nkind
(P
) in N_Short_Circuit
7680 and then N
= Right_Opnd
(P
)
7685 -- Similarly, if we are in an if expression and not part of the
7686 -- condition, then we return False, since neither the THEN or
7687 -- ELSE dependent expressions will always be elaborated.
7689 if Nkind
(P
) = N_If_Expression
7690 and then N
/= First
(Expressions
(P
))
7695 -- If within a case expression, and not part of the expression,
7696 -- then return False, since a particular dependent expression
7697 -- may not always be elaborated
7699 if Nkind
(P
) = N_Case_Expression
7700 and then N
/= Expression
(P
)
7705 -- While traversing the parent chain, if node N belongs to a
7706 -- statement, then it may never appear in a declarative region.
7708 if Nkind
(P
) in N_Statement_Other_Than_Procedure_Call
7709 or else Nkind
(P
) = N_Procedure_Call_Statement
7714 -- If we are at a declaration, record it and exit
7716 if Nkind
(P
) in N_Declaration
7717 and then Nkind
(P
) not in N_Subprogram_Specification
7730 return List_Containing
(N_Decl
) = Declarations
(S_Par
);
7732 end Safe_To_Capture_In_Parameter_Value
;
7738 procedure Mark_Non_Null
is
7740 -- Only case of interest is if node N is an entity name
7742 if Is_Entity_Name
(N
) then
7744 -- For sure, we want to clear an indication that this is known to
7745 -- be null, since if we get past this check, it definitely is not.
7747 Set_Is_Known_Null
(Entity
(N
), False);
7749 -- We can mark the entity as known to be non-null if either it is
7750 -- safe to capture the value, or in the case of an IN parameter,
7751 -- which is a constant, if the check we just installed is in the
7752 -- declarative region of the subprogram body. In this latter case,
7753 -- a check is decisive for the rest of the body if the expression
7754 -- is sure to be elaborated, since we know we have to elaborate
7755 -- all declarations before executing the body.
7757 -- Couldn't this always be part of Safe_To_Capture_Value ???
7759 if Safe_To_Capture_Value
(N
, Entity
(N
))
7760 or else Safe_To_Capture_In_Parameter_Value
7762 Set_Is_Known_Non_Null
(Entity
(N
));
7767 -- Start of processing for Install_Null_Excluding_Check
7770 -- No need to add null-excluding checks when the tree may not be fully
7773 if Serious_Errors_Detected
> 0 then
7777 pragma Assert
(Is_Access_Type
(Typ
));
7779 -- No check inside a generic, check will be emitted in instance
7781 if Inside_A_Generic
then
7785 -- No check needed if known to be non-null
7787 if Known_Non_Null
(N
) then
7791 -- If known to be null, here is where we generate a compile time check
7793 if Known_Null
(N
) then
7795 -- Avoid generating warning message inside init procs. In SPARK mode
7796 -- we can go ahead and call Apply_Compile_Time_Constraint_Error
7797 -- since it will be turned into an error in any case.
7799 if (not Inside_Init_Proc
or else SPARK_Mode
= On
)
7801 -- Do not emit the warning within a conditional expression,
7802 -- where the expression might not be evaluated, and the warning
7803 -- appear as extraneous noise.
7805 and then not Within_Case_Or_If_Expression
(N
)
7807 Apply_Compile_Time_Constraint_Error
7808 (N
, "null value not allowed here??", CE_Access_Check_Failed
);
7810 -- Remaining cases, where we silently insert the raise
7814 Make_Raise_Constraint_Error
(Loc
,
7815 Reason
=> CE_Access_Check_Failed
));
7822 -- If entity is never assigned, for sure a warning is appropriate
7824 if Is_Entity_Name
(N
) then
7825 Check_Unset_Reference
(N
);
7828 -- No check needed if checks are suppressed on the range. Note that we
7829 -- don't set Is_Known_Non_Null in this case (we could legitimately do
7830 -- so, since the program is erroneous, but we don't like to casually
7831 -- propagate such conclusions from erroneosity).
7833 if Access_Checks_Suppressed
(Typ
) then
7837 -- No check needed for access to concurrent record types generated by
7838 -- the expander. This is not just an optimization (though it does indeed
7839 -- remove junk checks). It also avoids generation of junk warnings.
7841 if Nkind
(N
) in N_Has_Chars
7842 and then Chars
(N
) = Name_uObject
7843 and then Is_Concurrent_Record_Type
7844 (Directly_Designated_Type
(Etype
(N
)))
7849 -- No check needed in interface thunks since the runtime check is
7850 -- already performed at the caller side.
7852 if Is_Thunk
(Current_Scope
) then
7856 -- No check needed for the Get_Current_Excep.all.all idiom generated by
7857 -- the expander within exception handlers, since we know that the value
7858 -- can never be null.
7860 -- Is this really the right way to do this? Normally we generate such
7861 -- code in the expander with checks off, and that's how we suppress this
7862 -- kind of junk check ???
7864 if Nkind
(N
) = N_Function_Call
7865 and then Nkind
(Name
(N
)) = N_Explicit_Dereference
7866 and then Nkind
(Prefix
(Name
(N
))) = N_Identifier
7867 and then Is_RTE
(Entity
(Prefix
(Name
(N
))), RE_Get_Current_Excep
)
7872 -- Otherwise install access check
7875 Make_Raise_Constraint_Error
(Loc
,
7878 Left_Opnd
=> Duplicate_Subexpr_Move_Checks
(N
),
7879 Right_Opnd
=> Make_Null
(Loc
)),
7880 Reason
=> CE_Access_Check_Failed
));
7883 end Install_Null_Excluding_Check
;
7885 -----------------------------------------
7886 -- Install_Primitive_Elaboration_Check --
7887 -----------------------------------------
7889 procedure Install_Primitive_Elaboration_Check
(Subp_Body
: Node_Id
) is
7890 function Within_Compilation_Unit_Instance
7891 (Subp_Id
: Entity_Id
) return Boolean;
7892 -- Determine whether subprogram Subp_Id appears within an instance which
7893 -- acts as a compilation unit.
7895 --------------------------------------
7896 -- Within_Compilation_Unit_Instance --
7897 --------------------------------------
7899 function Within_Compilation_Unit_Instance
7900 (Subp_Id
: Entity_Id
) return Boolean
7905 -- Examine the scope chain looking for a compilation-unit-level
7908 Pack
:= Scope
(Subp_Id
);
7909 while Present
(Pack
) and then Pack
/= Standard_Standard
loop
7910 if Ekind
(Pack
) = E_Package
7911 and then Is_Generic_Instance
(Pack
)
7912 and then Nkind
(Parent
(Unit_Declaration_Node
(Pack
))) =
7918 Pack
:= Scope
(Pack
);
7922 end Within_Compilation_Unit_Instance
;
7924 -- Local declarations
7926 Context
: constant Node_Id
:= Parent
(Subp_Body
);
7927 Loc
: constant Source_Ptr
:= Sloc
(Subp_Body
);
7928 Subp_Id
: constant Entity_Id
:= Unique_Defining_Entity
(Subp_Body
);
7929 Subp_Decl
: constant Node_Id
:= Unit_Declaration_Node
(Subp_Id
);
7932 Flag_Id
: Entity_Id
;
7935 Tag_Typ
: Entity_Id
;
7937 -- Start of processing for Install_Primitive_Elaboration_Check
7940 -- Do not generate an elaboration check in compilation modes where
7941 -- expansion is not desirable.
7943 if ASIS_Mode
or GNATprove_Mode
then
7946 -- Do not generate an elaboration check if all checks have been
7949 elsif Suppress_Checks
then
7952 -- Do not generate an elaboration check if the related subprogram is
7953 -- not subjected to accessibility checks.
7955 elsif Elaboration_Checks_Suppressed
(Subp_Id
) then
7958 -- Do not generate an elaboration check if such code is not desirable
7960 elsif Restriction_Active
(No_Elaboration_Code
) then
7963 -- Do not consider subprograms which act as compilation units, because
7964 -- they cannot be the target of a dispatching call.
7966 elsif Nkind
(Context
) = N_Compilation_Unit
then
7969 -- Do not consider anything other than nonabstract library-level source
7973 (Comes_From_Source
(Subp_Id
)
7974 and then Is_Library_Level_Entity
(Subp_Id
)
7975 and then Is_Primitive
(Subp_Id
)
7976 and then not Is_Abstract_Subprogram
(Subp_Id
))
7980 -- Do not consider inlined primitives, because once the body is inlined
7981 -- the reference to the elaboration flag will be out of place and will
7982 -- result in an undefined symbol.
7984 elsif Is_Inlined
(Subp_Id
) or else Has_Pragma_Inline
(Subp_Id
) then
7987 -- Do not generate a duplicate elaboration check. This happens only in
7988 -- the case of primitives completed by an expression function, as the
7989 -- corresponding body is apparently analyzed and expanded twice.
7991 elsif Analyzed
(Subp_Body
) then
7994 -- Do not consider primitives which occur within an instance that acts
7995 -- as a compilation unit. Such an instance defines its spec and body out
7996 -- of order (body is first) within the tree, which causes the reference
7997 -- to the elaboration flag to appear as an undefined symbol.
7999 elsif Within_Compilation_Unit_Instance
(Subp_Id
) then
8003 Tag_Typ
:= Find_Dispatching_Type
(Subp_Id
);
8005 -- Only tagged primitives may be the target of a dispatching call
8007 if No
(Tag_Typ
) then
8010 -- Do not consider finalization-related primitives, because they may
8011 -- need to be called while elaboration is taking place.
8013 elsif Is_Controlled
(Tag_Typ
)
8014 and then Nam_In
(Chars
(Subp_Id
), Name_Adjust
,
8021 -- Create the declaration of the elaboration flag. The name carries a
8022 -- unique counter in case of name overloading.
8025 Make_Defining_Identifier
(Loc
,
8026 Chars
=> New_External_Name
(Chars
(Subp_Id
), 'E', -1));
8027 Set_Is_Frozen
(Flag_Id
);
8029 -- Insert the declaration of the elaboration flag in front of the
8030 -- primitive spec and analyze it in the proper context.
8032 Push_Scope
(Scope
(Subp_Id
));
8035 -- E : Boolean := False;
8037 Insert_Action
(Subp_Decl
,
8038 Make_Object_Declaration
(Loc
,
8039 Defining_Identifier
=> Flag_Id
,
8040 Object_Definition
=> New_Occurrence_Of
(Standard_Boolean
, Loc
),
8041 Expression
=> New_Occurrence_Of
(Standard_False
, Loc
)));
8044 -- Prevent the compiler from optimizing the elaboration check by killing
8045 -- the current value of the flag and the associated assignment.
8047 Set_Current_Value
(Flag_Id
, Empty
);
8048 Set_Last_Assignment
(Flag_Id
, Empty
);
8050 -- Add a check at the top of the body declarations to ensure that the
8051 -- elaboration flag has been set.
8053 Decls
:= Declarations
(Subp_Body
);
8057 Set_Declarations
(Subp_Body
, Decls
);
8062 -- raise Program_Error with "access before elaboration";
8066 Make_Raise_Program_Error
(Loc
,
8069 Right_Opnd
=> New_Occurrence_Of
(Flag_Id
, Loc
)),
8070 Reason
=> PE_Access_Before_Elaboration
));
8072 Analyze
(First
(Decls
));
8074 -- Set the elaboration flag once the body has been elaborated. Insert
8075 -- the statement after the subprogram stub when the primitive body is
8078 if Nkind
(Context
) = N_Subunit
then
8079 Set_Ins
:= Corresponding_Stub
(Context
);
8081 Set_Ins
:= Subp_Body
;
8088 Make_Assignment_Statement
(Loc
,
8089 Name
=> New_Occurrence_Of
(Flag_Id
, Loc
),
8090 Expression
=> New_Occurrence_Of
(Standard_True
, Loc
));
8092 -- Mark the assignment statement as elaboration code. This allows the
8093 -- early call region mechanism (see Sem_Elab) to properly ignore such
8094 -- assignments even though they are non-preelaborable code.
8096 Set_Is_Elaboration_Code
(Set_Stmt
);
8098 Insert_After_And_Analyze
(Set_Ins
, Set_Stmt
);
8099 end Install_Primitive_Elaboration_Check
;
8101 --------------------------
8102 -- Install_Static_Check --
8103 --------------------------
8105 procedure Install_Static_Check
(R_Cno
: Node_Id
; Loc
: Source_Ptr
) is
8106 Stat
: constant Boolean := Is_OK_Static_Expression
(R_Cno
);
8107 Typ
: constant Entity_Id
:= Etype
(R_Cno
);
8111 Make_Raise_Constraint_Error
(Loc
,
8112 Reason
=> CE_Range_Check_Failed
));
8113 Set_Analyzed
(R_Cno
);
8114 Set_Etype
(R_Cno
, Typ
);
8115 Set_Raises_Constraint_Error
(R_Cno
);
8116 Set_Is_Static_Expression
(R_Cno
, Stat
);
8118 -- Now deal with possible local raise handling
8120 Possible_Local_Raise
(R_Cno
, Standard_Constraint_Error
);
8121 end Install_Static_Check
;
8123 -------------------------
8124 -- Is_Check_Suppressed --
8125 -------------------------
8127 function Is_Check_Suppressed
(E
: Entity_Id
; C
: Check_Id
) return Boolean is
8128 Ptr
: Suppress_Stack_Entry_Ptr
;
8131 -- First search the local entity suppress stack. We search this from the
8132 -- top of the stack down so that we get the innermost entry that applies
8133 -- to this case if there are nested entries.
8135 Ptr
:= Local_Suppress_Stack_Top
;
8136 while Ptr
/= null loop
8137 if (Ptr
.Entity
= Empty
or else Ptr
.Entity
= E
)
8138 and then (Ptr
.Check
= All_Checks
or else Ptr
.Check
= C
)
8140 return Ptr
.Suppress
;
8146 -- Now search the global entity suppress table for a matching entry.
8147 -- We also search this from the top down so that if there are multiple
8148 -- pragmas for the same entity, the last one applies (not clear what
8149 -- or whether the RM specifies this handling, but it seems reasonable).
8151 Ptr
:= Global_Suppress_Stack_Top
;
8152 while Ptr
/= null loop
8153 if (Ptr
.Entity
= Empty
or else Ptr
.Entity
= E
)
8154 and then (Ptr
.Check
= All_Checks
or else Ptr
.Check
= C
)
8156 return Ptr
.Suppress
;
8162 -- If we did not find a matching entry, then use the normal scope
8163 -- suppress value after all (actually this will be the global setting
8164 -- since it clearly was not overridden at any point). For a predefined
8165 -- check, we test the specific flag. For a user defined check, we check
8166 -- the All_Checks flag. The Overflow flag requires special handling to
8167 -- deal with the General vs Assertion case.
8169 if C
= Overflow_Check
then
8170 return Overflow_Checks_Suppressed
(Empty
);
8172 elsif C
in Predefined_Check_Id
then
8173 return Scope_Suppress
.Suppress
(C
);
8176 return Scope_Suppress
.Suppress
(All_Checks
);
8178 end Is_Check_Suppressed
;
8180 ---------------------
8181 -- Kill_All_Checks --
8182 ---------------------
8184 procedure Kill_All_Checks
is
8186 if Debug_Flag_CC
then
8187 w
("Kill_All_Checks");
8190 -- We reset the number of saved checks to zero, and also modify all
8191 -- stack entries for statement ranges to indicate that the number of
8192 -- checks at each level is now zero.
8194 Num_Saved_Checks
:= 0;
8196 -- Note: the Int'Min here avoids any possibility of J being out of
8197 -- range when called from e.g. Conditional_Statements_Begin.
8199 for J
in 1 .. Int
'Min (Saved_Checks_TOS
, Saved_Checks_Stack
'Last) loop
8200 Saved_Checks_Stack
(J
) := 0;
8202 end Kill_All_Checks
;
8208 procedure Kill_Checks
(V
: Entity_Id
) is
8210 if Debug_Flag_CC
then
8211 w
("Kill_Checks for entity", Int
(V
));
8214 for J
in 1 .. Num_Saved_Checks
loop
8215 if Saved_Checks
(J
).Entity
= V
then
8216 if Debug_Flag_CC
then
8217 w
(" Checks killed for saved check ", J
);
8220 Saved_Checks
(J
).Killed
:= True;
8225 ------------------------------
8226 -- Length_Checks_Suppressed --
8227 ------------------------------
8229 function Length_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
8231 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
8232 return Is_Check_Suppressed
(E
, Length_Check
);
8234 return Scope_Suppress
.Suppress
(Length_Check
);
8236 end Length_Checks_Suppressed
;
8238 -----------------------
8239 -- Make_Bignum_Block --
8240 -----------------------
8242 function Make_Bignum_Block
(Loc
: Source_Ptr
) return Node_Id
is
8243 M
: constant Entity_Id
:= Make_Defining_Identifier
(Loc
, Name_uM
);
8246 Make_Block_Statement
(Loc
,
8248 New_List
(Build_SS_Mark_Call
(Loc
, M
)),
8249 Handled_Statement_Sequence
=>
8250 Make_Handled_Sequence_Of_Statements
(Loc
,
8251 Statements
=> New_List
(Build_SS_Release_Call
(Loc
, M
))));
8252 end Make_Bignum_Block
;
8254 ----------------------------------
8255 -- Minimize_Eliminate_Overflows --
8256 ----------------------------------
8258 -- This is a recursive routine that is called at the top of an expression
8259 -- tree to properly process overflow checking for a whole subtree by making
8260 -- recursive calls to process operands. This processing may involve the use
8261 -- of bignum or long long integer arithmetic, which will change the types
8262 -- of operands and results. That's why we can't do this bottom up (since
8263 -- it would interfere with semantic analysis).
8265 -- What happens is that if MINIMIZED/ELIMINATED mode is in effect then
8266 -- the operator expansion routines, as well as the expansion routines for
8267 -- if/case expression, do nothing (for the moment) except call the routine
8268 -- to apply the overflow check (Apply_Arithmetic_Overflow_Check). That
8269 -- routine does nothing for non top-level nodes, so at the point where the
8270 -- call is made for the top level node, the entire expression subtree has
8271 -- not been expanded, or processed for overflow. All that has to happen as
8272 -- a result of the top level call to this routine.
8274 -- As noted above, the overflow processing works by making recursive calls
8275 -- for the operands, and figuring out what to do, based on the processing
8276 -- of these operands (e.g. if a bignum operand appears, the parent op has
8277 -- to be done in bignum mode), and the determined ranges of the operands.
8279 -- After possible rewriting of a constituent subexpression node, a call is
8280 -- made to either reexpand the node (if nothing has changed) or reanalyze
8281 -- the node (if it has been modified by the overflow check processing). The
8282 -- Analyzed_Flag is set to False before the reexpand/reanalyze. To avoid
8283 -- a recursive call into the whole overflow apparatus, an important rule
8284 -- for this call is that the overflow handling mode must be temporarily set
8287 procedure Minimize_Eliminate_Overflows
8291 Top_Level
: Boolean)
8293 Rtyp
: constant Entity_Id
:= Etype
(N
);
8294 pragma Assert
(Is_Signed_Integer_Type
(Rtyp
));
8295 -- Result type, must be a signed integer type
8297 Check_Mode
: constant Overflow_Mode_Type
:= Overflow_Check_Mode
;
8298 pragma Assert
(Check_Mode
in Minimized_Or_Eliminated
);
8300 Loc
: constant Source_Ptr
:= Sloc
(N
);
8303 -- Ranges of values for right operand (operator case)
8305 Llo
: Uint
:= No_Uint
; -- initialize to prevent warning
8306 Lhi
: Uint
:= No_Uint
; -- initialize to prevent warning
8307 -- Ranges of values for left operand (operator case)
8309 LLIB
: constant Entity_Id
:= Base_Type
(Standard_Long_Long_Integer
);
8310 -- Operands and results are of this type when we convert
8312 LLLo
: constant Uint
:= Intval
(Type_Low_Bound
(LLIB
));
8313 LLHi
: constant Uint
:= Intval
(Type_High_Bound
(LLIB
));
8314 -- Bounds of Long_Long_Integer
8316 Binary
: constant Boolean := Nkind
(N
) in N_Binary_Op
;
8317 -- Indicates binary operator case
8320 -- Used in call to Determine_Range
8322 Bignum_Operands
: Boolean;
8323 -- Set True if one or more operands is already of type Bignum, meaning
8324 -- that for sure (regardless of Top_Level setting) we are committed to
8325 -- doing the operation in Bignum mode (or in the case of a case or if
8326 -- expression, converting all the dependent expressions to Bignum).
8328 Long_Long_Integer_Operands
: Boolean;
8329 -- Set True if one or more operands is already of type Long_Long_Integer
8330 -- which means that if the result is known to be in the result type
8331 -- range, then we must convert such operands back to the result type.
8333 procedure Reanalyze
(Typ
: Entity_Id
; Suppress
: Boolean := False);
8334 -- This is called when we have modified the node and we therefore need
8335 -- to reanalyze it. It is important that we reset the mode to STRICT for
8336 -- this reanalysis, since if we leave it in MINIMIZED or ELIMINATED mode
8337 -- we would reenter this routine recursively which would not be good.
8338 -- The argument Suppress is set True if we also want to suppress
8339 -- overflow checking for the reexpansion (this is set when we know
8340 -- overflow is not possible). Typ is the type for the reanalysis.
8342 procedure Reexpand
(Suppress
: Boolean := False);
8343 -- This is like Reanalyze, but does not do the Analyze step, it only
8344 -- does a reexpansion. We do this reexpansion in STRICT mode, so that
8345 -- instead of reentering the MINIMIZED/ELIMINATED mode processing, we
8346 -- follow the normal expansion path (e.g. converting A**4 to A**2**2).
8347 -- Note that skipping reanalysis is not just an optimization, testing
8348 -- has showed up several complex cases in which reanalyzing an already
8349 -- analyzed node causes incorrect behavior.
8351 function In_Result_Range
return Boolean;
8352 -- Returns True iff Lo .. Hi are within range of the result type
8354 procedure Max
(A
: in out Uint
; B
: Uint
);
8355 -- If A is No_Uint, sets A to B, else to UI_Max (A, B)
8357 procedure Min
(A
: in out Uint
; B
: Uint
);
8358 -- If A is No_Uint, sets A to B, else to UI_Min (A, B)
8360 ---------------------
8361 -- In_Result_Range --
8362 ---------------------
8364 function In_Result_Range
return Boolean is
8366 if Lo
= No_Uint
or else Hi
= No_Uint
then
8369 elsif Is_OK_Static_Subtype
(Etype
(N
)) then
8370 return Lo
>= Expr_Value
(Type_Low_Bound
(Rtyp
))
8372 Hi
<= Expr_Value
(Type_High_Bound
(Rtyp
));
8375 return Lo
>= Expr_Value
(Type_Low_Bound
(Base_Type
(Rtyp
)))
8377 Hi
<= Expr_Value
(Type_High_Bound
(Base_Type
(Rtyp
)));
8379 end In_Result_Range
;
8385 procedure Max
(A
: in out Uint
; B
: Uint
) is
8387 if A
= No_Uint
or else B
> A
then
8396 procedure Min
(A
: in out Uint
; B
: Uint
) is
8398 if A
= No_Uint
or else B
< A
then
8407 procedure Reanalyze
(Typ
: Entity_Id
; Suppress
: Boolean := False) is
8408 Svg
: constant Overflow_Mode_Type
:=
8409 Scope_Suppress
.Overflow_Mode_General
;
8410 Sva
: constant Overflow_Mode_Type
:=
8411 Scope_Suppress
.Overflow_Mode_Assertions
;
8412 Svo
: constant Boolean :=
8413 Scope_Suppress
.Suppress
(Overflow_Check
);
8416 Scope_Suppress
.Overflow_Mode_General
:= Strict
;
8417 Scope_Suppress
.Overflow_Mode_Assertions
:= Strict
;
8420 Scope_Suppress
.Suppress
(Overflow_Check
) := True;
8423 Analyze_And_Resolve
(N
, Typ
);
8425 Scope_Suppress
.Suppress
(Overflow_Check
) := Svo
;
8426 Scope_Suppress
.Overflow_Mode_General
:= Svg
;
8427 Scope_Suppress
.Overflow_Mode_Assertions
:= Sva
;
8434 procedure Reexpand
(Suppress
: Boolean := False) is
8435 Svg
: constant Overflow_Mode_Type
:=
8436 Scope_Suppress
.Overflow_Mode_General
;
8437 Sva
: constant Overflow_Mode_Type
:=
8438 Scope_Suppress
.Overflow_Mode_Assertions
;
8439 Svo
: constant Boolean :=
8440 Scope_Suppress
.Suppress
(Overflow_Check
);
8443 Scope_Suppress
.Overflow_Mode_General
:= Strict
;
8444 Scope_Suppress
.Overflow_Mode_Assertions
:= Strict
;
8445 Set_Analyzed
(N
, False);
8448 Scope_Suppress
.Suppress
(Overflow_Check
) := True;
8453 Scope_Suppress
.Suppress
(Overflow_Check
) := Svo
;
8454 Scope_Suppress
.Overflow_Mode_General
:= Svg
;
8455 Scope_Suppress
.Overflow_Mode_Assertions
:= Sva
;
8458 -- Start of processing for Minimize_Eliminate_Overflows
8461 -- Default initialize Lo and Hi since these are not guaranteed to be
8467 -- Case where we do not have a signed integer arithmetic operation
8469 if not Is_Signed_Integer_Arithmetic_Op
(N
) then
8471 -- Use the normal Determine_Range routine to get the range. We
8472 -- don't require operands to be valid, invalid values may result in
8473 -- rubbish results where the result has not been properly checked for
8474 -- overflow, that's fine.
8476 Determine_Range
(N
, OK
, Lo
, Hi
, Assume_Valid
=> False);
8478 -- If Determine_Range did not work (can this in fact happen? Not
8479 -- clear but might as well protect), use type bounds.
8482 Lo
:= Intval
(Type_Low_Bound
(Base_Type
(Etype
(N
))));
8483 Hi
:= Intval
(Type_High_Bound
(Base_Type
(Etype
(N
))));
8486 -- If we don't have a binary operator, all we have to do is to set
8487 -- the Hi/Lo range, so we are done.
8491 -- Processing for if expression
8493 elsif Nkind
(N
) = N_If_Expression
then
8495 Then_DE
: constant Node_Id
:= Next
(First
(Expressions
(N
)));
8496 Else_DE
: constant Node_Id
:= Next
(Then_DE
);
8499 Bignum_Operands
:= False;
8501 Minimize_Eliminate_Overflows
8502 (Then_DE
, Lo
, Hi
, Top_Level
=> False);
8504 if Lo
= No_Uint
then
8505 Bignum_Operands
:= True;
8508 Minimize_Eliminate_Overflows
8509 (Else_DE
, Rlo
, Rhi
, Top_Level
=> False);
8511 if Rlo
= No_Uint
then
8512 Bignum_Operands
:= True;
8514 Long_Long_Integer_Operands
:=
8515 Etype
(Then_DE
) = LLIB
or else Etype
(Else_DE
) = LLIB
;
8521 -- If at least one of our operands is now Bignum, we must rebuild
8522 -- the if expression to use Bignum operands. We will analyze the
8523 -- rebuilt if expression with overflow checks off, since once we
8524 -- are in bignum mode, we are all done with overflow checks.
8526 if Bignum_Operands
then
8528 Make_If_Expression
(Loc
,
8529 Expressions
=> New_List
(
8530 Remove_Head
(Expressions
(N
)),
8531 Convert_To_Bignum
(Then_DE
),
8532 Convert_To_Bignum
(Else_DE
)),
8533 Is_Elsif
=> Is_Elsif
(N
)));
8535 Reanalyze
(RTE
(RE_Bignum
), Suppress
=> True);
8537 -- If we have no Long_Long_Integer operands, then we are in result
8538 -- range, since it means that none of our operands felt the need
8539 -- to worry about overflow (otherwise it would have already been
8540 -- converted to long long integer or bignum). We reexpand to
8541 -- complete the expansion of the if expression (but we do not
8542 -- need to reanalyze).
8544 elsif not Long_Long_Integer_Operands
then
8545 Set_Do_Overflow_Check
(N
, False);
8548 -- Otherwise convert us to long long integer mode. Note that we
8549 -- don't need any further overflow checking at this level.
8552 Convert_To_And_Rewrite
(LLIB
, Then_DE
);
8553 Convert_To_And_Rewrite
(LLIB
, Else_DE
);
8554 Set_Etype
(N
, LLIB
);
8556 -- Now reanalyze with overflow checks off
8558 Set_Do_Overflow_Check
(N
, False);
8559 Reanalyze
(LLIB
, Suppress
=> True);
8565 -- Here for case expression
8567 elsif Nkind
(N
) = N_Case_Expression
then
8568 Bignum_Operands
:= False;
8569 Long_Long_Integer_Operands
:= False;
8575 -- Loop through expressions applying recursive call
8577 Alt
:= First
(Alternatives
(N
));
8578 while Present
(Alt
) loop
8580 Aexp
: constant Node_Id
:= Expression
(Alt
);
8583 Minimize_Eliminate_Overflows
8584 (Aexp
, Lo
, Hi
, Top_Level
=> False);
8586 if Lo
= No_Uint
then
8587 Bignum_Operands
:= True;
8588 elsif Etype
(Aexp
) = LLIB
then
8589 Long_Long_Integer_Operands
:= True;
8596 -- If we have no bignum or long long integer operands, it means
8597 -- that none of our dependent expressions could raise overflow.
8598 -- In this case, we simply return with no changes except for
8599 -- resetting the overflow flag, since we are done with overflow
8600 -- checks for this node. We will reexpand to get the needed
8601 -- expansion for the case expression, but we do not need to
8602 -- reanalyze, since nothing has changed.
8604 if not (Bignum_Operands
or Long_Long_Integer_Operands
) then
8605 Set_Do_Overflow_Check
(N
, False);
8606 Reexpand
(Suppress
=> True);
8608 -- Otherwise we are going to rebuild the case expression using
8609 -- either bignum or long long integer operands throughout.
8614 pragma Warnings
(Off
, Rtype
);
8619 New_Alts
:= New_List
;
8620 Alt
:= First
(Alternatives
(N
));
8621 while Present
(Alt
) loop
8622 if Bignum_Operands
then
8623 New_Exp
:= Convert_To_Bignum
(Expression
(Alt
));
8624 Rtype
:= RTE
(RE_Bignum
);
8626 New_Exp
:= Convert_To
(LLIB
, Expression
(Alt
));
8630 Append_To
(New_Alts
,
8631 Make_Case_Expression_Alternative
(Sloc
(Alt
),
8633 Discrete_Choices
=> Discrete_Choices
(Alt
),
8634 Expression
=> New_Exp
));
8640 Make_Case_Expression
(Loc
,
8641 Expression
=> Expression
(N
),
8642 Alternatives
=> New_Alts
));
8644 Reanalyze
(Rtype
, Suppress
=> True);
8652 -- If we have an arithmetic operator we make recursive calls on the
8653 -- operands to get the ranges (and to properly process the subtree
8654 -- that lies below us).
8656 Minimize_Eliminate_Overflows
8657 (Right_Opnd
(N
), Rlo
, Rhi
, Top_Level
=> False);
8660 Minimize_Eliminate_Overflows
8661 (Left_Opnd
(N
), Llo
, Lhi
, Top_Level
=> False);
8664 -- Record if we have Long_Long_Integer operands
8666 Long_Long_Integer_Operands
:=
8667 Etype
(Right_Opnd
(N
)) = LLIB
8668 or else (Binary
and then Etype
(Left_Opnd
(N
)) = LLIB
);
8670 -- If either operand is a bignum, then result will be a bignum and we
8671 -- don't need to do any range analysis. As previously discussed we could
8672 -- do range analysis in such cases, but it could mean working with giant
8673 -- numbers at compile time for very little gain (the number of cases
8674 -- in which we could slip back from bignum mode is small).
8676 if Rlo
= No_Uint
or else (Binary
and then Llo
= No_Uint
) then
8679 Bignum_Operands
:= True;
8681 -- Otherwise compute result range
8684 Bignum_Operands
:= False;
8692 Hi
:= UI_Max
(abs Rlo
, abs Rhi
);
8704 -- If the right operand can only be zero, set 0..0
8706 if Rlo
= 0 and then Rhi
= 0 then
8710 -- Possible bounds of division must come from dividing end
8711 -- values of the input ranges (four possibilities), provided
8712 -- zero is not included in the possible values of the right
8715 -- Otherwise, we just consider two intervals of values for
8716 -- the right operand: the interval of negative values (up to
8717 -- -1) and the interval of positive values (starting at 1).
8718 -- Since division by 1 is the identity, and division by -1
8719 -- is negation, we get all possible bounds of division in that
8720 -- case by considering:
8721 -- - all values from the division of end values of input
8723 -- - the end values of the left operand;
8724 -- - the negation of the end values of the left operand.
8728 Mrk
: constant Uintp
.Save_Mark
:= Mark
;
8729 -- Mark so we can release the RR and Ev values
8737 -- Discard extreme values of zero for the divisor, since
8738 -- they will simply result in an exception in any case.
8746 -- Compute possible bounds coming from dividing end
8747 -- values of the input ranges.
8754 Lo
:= UI_Min
(UI_Min
(Ev1
, Ev2
), UI_Min
(Ev3
, Ev4
));
8755 Hi
:= UI_Max
(UI_Max
(Ev1
, Ev2
), UI_Max
(Ev3
, Ev4
));
8757 -- If the right operand can be both negative or positive,
8758 -- include the end values of the left operand in the
8759 -- extreme values, as well as their negation.
8761 if Rlo
< 0 and then Rhi
> 0 then
8768 UI_Min
(UI_Min
(Ev1
, Ev2
), UI_Min
(Ev3
, Ev4
)));
8770 UI_Max
(UI_Max
(Ev1
, Ev2
), UI_Max
(Ev3
, Ev4
)));
8773 -- Release the RR and Ev values
8775 Release_And_Save
(Mrk
, Lo
, Hi
);
8783 -- Discard negative values for the exponent, since they will
8784 -- simply result in an exception in any case.
8792 -- Estimate number of bits in result before we go computing
8793 -- giant useless bounds. Basically the number of bits in the
8794 -- result is the number of bits in the base multiplied by the
8795 -- value of the exponent. If this is big enough that the result
8796 -- definitely won't fit in Long_Long_Integer, switch to bignum
8797 -- mode immediately, and avoid computing giant bounds.
8799 -- The comparison here is approximate, but conservative, it
8800 -- only clicks on cases that are sure to exceed the bounds.
8802 if Num_Bits
(UI_Max
(abs Llo
, abs Lhi
)) * Rhi
+ 1 > 100 then
8806 -- If right operand is zero then result is 1
8813 -- High bound comes either from exponentiation of largest
8814 -- positive value to largest exponent value, or from
8815 -- the exponentiation of most negative value to an
8829 if Rhi
mod 2 = 0 then
8832 Hi2
:= Llo
** (Rhi
- 1);
8838 Hi
:= UI_Max
(Hi1
, Hi2
);
8841 -- Result can only be negative if base can be negative
8844 if Rhi
mod 2 = 0 then
8845 Lo
:= Llo
** (Rhi
- 1);
8850 -- Otherwise low bound is minimum ** minimum
8867 Maxabs
: constant Uint
:= UI_Max
(abs Rlo
, abs Rhi
) - 1;
8868 -- This is the maximum absolute value of the result
8874 -- The result depends only on the sign and magnitude of
8875 -- the right operand, it does not depend on the sign or
8876 -- magnitude of the left operand.
8889 when N_Op_Multiply
=>
8891 -- Possible bounds of multiplication must come from multiplying
8892 -- end values of the input ranges (four possibilities).
8895 Mrk
: constant Uintp
.Save_Mark
:= Mark
;
8896 -- Mark so we can release the Ev values
8898 Ev1
: constant Uint
:= Llo
* Rlo
;
8899 Ev2
: constant Uint
:= Llo
* Rhi
;
8900 Ev3
: constant Uint
:= Lhi
* Rlo
;
8901 Ev4
: constant Uint
:= Lhi
* Rhi
;
8904 Lo
:= UI_Min
(UI_Min
(Ev1
, Ev2
), UI_Min
(Ev3
, Ev4
));
8905 Hi
:= UI_Max
(UI_Max
(Ev1
, Ev2
), UI_Max
(Ev3
, Ev4
));
8907 -- Release the Ev values
8909 Release_And_Save
(Mrk
, Lo
, Hi
);
8912 -- Plus operator (affirmation)
8922 Maxabs
: constant Uint
:= UI_Max
(abs Rlo
, abs Rhi
) - 1;
8923 -- This is the maximum absolute value of the result. Note
8924 -- that the result range does not depend on the sign of the
8931 -- Case of left operand negative, which results in a range
8932 -- of -Maxabs .. 0 for those negative values. If there are
8933 -- no negative values then Lo value of result is always 0.
8939 -- Case of left operand positive
8948 when N_Op_Subtract
=>
8952 -- Nothing else should be possible
8955 raise Program_Error
;
8959 -- Here for the case where we have not rewritten anything (no bignum
8960 -- operands or long long integer operands), and we know the result.
8961 -- If we know we are in the result range, and we do not have Bignum
8962 -- operands or Long_Long_Integer operands, we can just reexpand with
8963 -- overflow checks turned off (since we know we cannot have overflow).
8964 -- As always the reexpansion is required to complete expansion of the
8965 -- operator, but we do not need to reanalyze, and we prevent recursion
8966 -- by suppressing the check.
8968 if not (Bignum_Operands
or Long_Long_Integer_Operands
)
8969 and then In_Result_Range
8971 Set_Do_Overflow_Check
(N
, False);
8972 Reexpand
(Suppress
=> True);
8975 -- Here we know that we are not in the result range, and in the general
8976 -- case we will move into either the Bignum or Long_Long_Integer domain
8977 -- to compute the result. However, there is one exception. If we are
8978 -- at the top level, and we do not have Bignum or Long_Long_Integer
8979 -- operands, we will have to immediately convert the result back to
8980 -- the result type, so there is no point in Bignum/Long_Long_Integer
8984 and then not (Bignum_Operands
or Long_Long_Integer_Operands
)
8986 -- One further refinement. If we are at the top level, but our parent
8987 -- is a type conversion, then go into bignum or long long integer node
8988 -- since the result will be converted to that type directly without
8989 -- going through the result type, and we may avoid an overflow. This
8990 -- is the case for example of Long_Long_Integer (A ** 4), where A is
8991 -- of type Integer, and the result A ** 4 fits in Long_Long_Integer
8992 -- but does not fit in Integer.
8994 and then Nkind
(Parent
(N
)) /= N_Type_Conversion
8996 -- Here keep original types, but we need to complete analysis
8998 -- One subtlety. We can't just go ahead and do an analyze operation
8999 -- here because it will cause recursion into the whole MINIMIZED/
9000 -- ELIMINATED overflow processing which is not what we want. Here
9001 -- we are at the top level, and we need a check against the result
9002 -- mode (i.e. we want to use STRICT mode). So do exactly that.
9003 -- Also, we have not modified the node, so this is a case where
9004 -- we need to reexpand, but not reanalyze.
9009 -- Cases where we do the operation in Bignum mode. This happens either
9010 -- because one of our operands is in Bignum mode already, or because
9011 -- the computed bounds are outside the bounds of Long_Long_Integer,
9012 -- which in some cases can be indicated by Hi and Lo being No_Uint.
9014 -- Note: we could do better here and in some cases switch back from
9015 -- Bignum mode to normal mode, e.g. big mod 2 must be in the range
9016 -- 0 .. 1, but the cases are rare and it is not worth the effort.
9017 -- Failing to do this switching back is only an efficiency issue.
9019 elsif Lo
= No_Uint
or else Lo
< LLLo
or else Hi
> LLHi
then
9021 -- OK, we are definitely outside the range of Long_Long_Integer. The
9022 -- question is whether to move to Bignum mode, or stay in the domain
9023 -- of Long_Long_Integer, signalling that an overflow check is needed.
9025 -- Obviously in MINIMIZED mode we stay with LLI, since we are not in
9026 -- the Bignum business. In ELIMINATED mode, we will normally move
9027 -- into Bignum mode, but there is an exception if neither of our
9028 -- operands is Bignum now, and we are at the top level (Top_Level
9029 -- set True). In this case, there is no point in moving into Bignum
9030 -- mode to prevent overflow if the caller will immediately convert
9031 -- the Bignum value back to LLI with an overflow check. It's more
9032 -- efficient to stay in LLI mode with an overflow check (if needed)
9034 if Check_Mode
= Minimized
9035 or else (Top_Level
and not Bignum_Operands
)
9037 if Do_Overflow_Check
(N
) then
9038 Enable_Overflow_Check
(N
);
9041 -- The result now has to be in Long_Long_Integer mode, so adjust
9042 -- the possible range to reflect this. Note these calls also
9043 -- change No_Uint values from the top level case to LLI bounds.
9048 -- Otherwise we are in ELIMINATED mode and we switch to Bignum mode
9051 pragma Assert
(Check_Mode
= Eliminated
);
9060 Fent
:= RTE
(RE_Big_Abs
);
9063 Fent
:= RTE
(RE_Big_Add
);
9066 Fent
:= RTE
(RE_Big_Div
);
9069 Fent
:= RTE
(RE_Big_Exp
);
9072 Fent
:= RTE
(RE_Big_Neg
);
9075 Fent
:= RTE
(RE_Big_Mod
);
9077 when N_Op_Multiply
=>
9078 Fent
:= RTE
(RE_Big_Mul
);
9081 Fent
:= RTE
(RE_Big_Rem
);
9083 when N_Op_Subtract
=>
9084 Fent
:= RTE
(RE_Big_Sub
);
9086 -- Anything else is an internal error, this includes the
9087 -- N_Op_Plus case, since how can plus cause the result
9088 -- to be out of range if the operand is in range?
9091 raise Program_Error
;
9094 -- Construct argument list for Bignum call, converting our
9095 -- operands to Bignum form if they are not already there.
9100 Append_To
(Args
, Convert_To_Bignum
(Left_Opnd
(N
)));
9103 Append_To
(Args
, Convert_To_Bignum
(Right_Opnd
(N
)));
9105 -- Now rewrite the arithmetic operator with a call to the
9106 -- corresponding bignum function.
9109 Make_Function_Call
(Loc
,
9110 Name
=> New_Occurrence_Of
(Fent
, Loc
),
9111 Parameter_Associations
=> Args
));
9112 Reanalyze
(RTE
(RE_Bignum
), Suppress
=> True);
9114 -- Indicate result is Bignum mode
9122 -- Otherwise we are in range of Long_Long_Integer, so no overflow
9123 -- check is required, at least not yet.
9126 Set_Do_Overflow_Check
(N
, False);
9129 -- Here we are not in Bignum territory, but we may have long long
9130 -- integer operands that need special handling. First a special check:
9131 -- If an exponentiation operator exponent is of type Long_Long_Integer,
9132 -- it means we converted it to prevent overflow, but exponentiation
9133 -- requires a Natural right operand, so convert it back to Natural.
9134 -- This conversion may raise an exception which is fine.
9136 if Nkind
(N
) = N_Op_Expon
and then Etype
(Right_Opnd
(N
)) = LLIB
then
9137 Convert_To_And_Rewrite
(Standard_Natural
, Right_Opnd
(N
));
9140 -- Here we will do the operation in Long_Long_Integer. We do this even
9141 -- if we know an overflow check is required, better to do this in long
9142 -- long integer mode, since we are less likely to overflow.
9144 -- Convert right or only operand to Long_Long_Integer, except that
9145 -- we do not touch the exponentiation right operand.
9147 if Nkind
(N
) /= N_Op_Expon
then
9148 Convert_To_And_Rewrite
(LLIB
, Right_Opnd
(N
));
9151 -- Convert left operand to Long_Long_Integer for binary case
9154 Convert_To_And_Rewrite
(LLIB
, Left_Opnd
(N
));
9157 -- Reset node to unanalyzed
9159 Set_Analyzed
(N
, False);
9160 Set_Etype
(N
, Empty
);
9161 Set_Entity
(N
, Empty
);
9163 -- Now analyze this new node. This reanalysis will complete processing
9164 -- for the node. In particular we will complete the expansion of an
9165 -- exponentiation operator (e.g. changing A ** 2 to A * A), and also
9166 -- we will complete any division checks (since we have not changed the
9167 -- setting of the Do_Division_Check flag).
9169 -- We do this reanalysis in STRICT mode to avoid recursion into the
9170 -- MINIMIZED/ELIMINATED handling, since we are now done with that.
9173 SG
: constant Overflow_Mode_Type
:=
9174 Scope_Suppress
.Overflow_Mode_General
;
9175 SA
: constant Overflow_Mode_Type
:=
9176 Scope_Suppress
.Overflow_Mode_Assertions
;
9179 Scope_Suppress
.Overflow_Mode_General
:= Strict
;
9180 Scope_Suppress
.Overflow_Mode_Assertions
:= Strict
;
9182 if not Do_Overflow_Check
(N
) then
9183 Reanalyze
(LLIB
, Suppress
=> True);
9188 Scope_Suppress
.Overflow_Mode_General
:= SG
;
9189 Scope_Suppress
.Overflow_Mode_Assertions
:= SA
;
9191 end Minimize_Eliminate_Overflows
;
9193 -------------------------
9194 -- Overflow_Check_Mode --
9195 -------------------------
9197 function Overflow_Check_Mode
return Overflow_Mode_Type
is
9199 if In_Assertion_Expr
= 0 then
9200 return Scope_Suppress
.Overflow_Mode_General
;
9202 return Scope_Suppress
.Overflow_Mode_Assertions
;
9204 end Overflow_Check_Mode
;
9206 --------------------------------
9207 -- Overflow_Checks_Suppressed --
9208 --------------------------------
9210 function Overflow_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
9212 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
9213 return Is_Check_Suppressed
(E
, Overflow_Check
);
9215 return Scope_Suppress
.Suppress
(Overflow_Check
);
9217 end Overflow_Checks_Suppressed
;
9219 ---------------------------------
9220 -- Predicate_Checks_Suppressed --
9221 ---------------------------------
9223 function Predicate_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
9225 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
9226 return Is_Check_Suppressed
(E
, Predicate_Check
);
9228 return Scope_Suppress
.Suppress
(Predicate_Check
);
9230 end Predicate_Checks_Suppressed
;
9232 -----------------------------
9233 -- Range_Checks_Suppressed --
9234 -----------------------------
9236 function Range_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
9239 if Kill_Range_Checks
(E
) then
9242 elsif Checks_May_Be_Suppressed
(E
) then
9243 return Is_Check_Suppressed
(E
, Range_Check
);
9247 return Scope_Suppress
.Suppress
(Range_Check
);
9248 end Range_Checks_Suppressed
;
9250 -----------------------------------------
9251 -- Range_Or_Validity_Checks_Suppressed --
9252 -----------------------------------------
9254 -- Note: the coding would be simpler here if we simply made appropriate
9255 -- calls to Range/Validity_Checks_Suppressed, but that would result in
9256 -- duplicated checks which we prefer to avoid.
9258 function Range_Or_Validity_Checks_Suppressed
9259 (Expr
: Node_Id
) return Boolean
9262 -- Immediate return if scope checks suppressed for either check
9264 if Scope_Suppress
.Suppress
(Range_Check
)
9266 Scope_Suppress
.Suppress
(Validity_Check
)
9271 -- If no expression, that's odd, decide that checks are suppressed,
9272 -- since we don't want anyone trying to do checks in this case, which
9273 -- is most likely the result of some other error.
9279 -- Expression is present, so perform suppress checks on type
9282 Typ
: constant Entity_Id
:= Etype
(Expr
);
9284 if Checks_May_Be_Suppressed
(Typ
)
9285 and then (Is_Check_Suppressed
(Typ
, Range_Check
)
9287 Is_Check_Suppressed
(Typ
, Validity_Check
))
9293 -- If expression is an entity name, perform checks on this entity
9295 if Is_Entity_Name
(Expr
) then
9297 Ent
: constant Entity_Id
:= Entity
(Expr
);
9299 if Checks_May_Be_Suppressed
(Ent
) then
9300 return Is_Check_Suppressed
(Ent
, Range_Check
)
9301 or else Is_Check_Suppressed
(Ent
, Validity_Check
);
9306 -- If we fall through, no checks suppressed
9309 end Range_Or_Validity_Checks_Suppressed
;
9315 procedure Remove_Checks
(Expr
: Node_Id
) is
9316 function Process
(N
: Node_Id
) return Traverse_Result
;
9317 -- Process a single node during the traversal
9319 procedure Traverse
is new Traverse_Proc
(Process
);
9320 -- The traversal procedure itself
9326 function Process
(N
: Node_Id
) return Traverse_Result
is
9328 if Nkind
(N
) not in N_Subexpr
then
9332 Set_Do_Range_Check
(N
, False);
9336 Traverse
(Left_Opnd
(N
));
9339 when N_Attribute_Reference
=>
9340 Set_Do_Overflow_Check
(N
, False);
9342 when N_Function_Call
=>
9343 Set_Do_Tag_Check
(N
, False);
9346 Set_Do_Overflow_Check
(N
, False);
9350 Set_Do_Division_Check
(N
, False);
9353 Set_Do_Length_Check
(N
, False);
9356 Set_Do_Division_Check
(N
, False);
9359 Set_Do_Length_Check
(N
, False);
9362 Set_Do_Division_Check
(N
, False);
9365 Set_Do_Length_Check
(N
, False);
9372 Traverse
(Left_Opnd
(N
));
9375 when N_Selected_Component
=>
9376 Set_Do_Discriminant_Check
(N
, False);
9378 when N_Type_Conversion
=>
9379 Set_Do_Length_Check
(N
, False);
9380 Set_Do_Tag_Check
(N
, False);
9381 Set_Do_Overflow_Check
(N
, False);
9390 -- Start of processing for Remove_Checks
9396 ----------------------------
9397 -- Selected_Length_Checks --
9398 ----------------------------
9400 function Selected_Length_Checks
9402 Target_Typ
: Entity_Id
;
9403 Source_Typ
: Entity_Id
;
9404 Warn_Node
: Node_Id
) return Check_Result
9406 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
9409 Expr_Actual
: Node_Id
;
9411 Cond
: Node_Id
:= Empty
;
9412 Do_Access
: Boolean := False;
9413 Wnode
: Node_Id
:= Warn_Node
;
9414 Ret_Result
: Check_Result
:= (Empty
, Empty
);
9415 Num_Checks
: Natural := 0;
9417 procedure Add_Check
(N
: Node_Id
);
9418 -- Adds the action given to Ret_Result if N is non-Empty
9420 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
;
9421 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
9422 -- Comments required ???
9424 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean;
9425 -- True for equal literals and for nodes that denote the same constant
9426 -- entity, even if its value is not a static constant. This includes the
9427 -- case of a discriminal reference within an init proc. Removes some
9428 -- obviously superfluous checks.
9430 function Length_E_Cond
9431 (Exptyp
: Entity_Id
;
9433 Indx
: Nat
) return Node_Id
;
9434 -- Returns expression to compute:
9435 -- Typ'Length /= Exptyp'Length
9437 function Length_N_Cond
9440 Indx
: Nat
) return Node_Id
;
9441 -- Returns expression to compute:
9442 -- Typ'Length /= Expr'Length
9448 procedure Add_Check
(N
: Node_Id
) is
9452 -- For now, ignore attempt to place more than two checks ???
9453 -- This is really worrisome, are we really discarding checks ???
9455 if Num_Checks
= 2 then
9459 pragma Assert
(Num_Checks
<= 1);
9460 Num_Checks
:= Num_Checks
+ 1;
9461 Ret_Result
(Num_Checks
) := N
;
9469 function Get_E_Length
(E
: Entity_Id
; Indx
: Nat
) return Node_Id
is
9470 SE
: constant Entity_Id
:= Scope
(E
);
9472 E1
: Entity_Id
:= E
;
9475 if Ekind
(Scope
(E
)) = E_Record_Type
9476 and then Has_Discriminants
(Scope
(E
))
9478 N
:= Build_Discriminal_Subtype_Of_Component
(E
);
9481 Insert_Action
(Ck_Node
, N
);
9482 E1
:= Defining_Identifier
(N
);
9486 if Ekind
(E1
) = E_String_Literal_Subtype
then
9488 Make_Integer_Literal
(Loc
,
9489 Intval
=> String_Literal_Length
(E1
));
9491 elsif SE
/= Standard_Standard
9492 and then Ekind
(Scope
(SE
)) = E_Protected_Type
9493 and then Has_Discriminants
(Scope
(SE
))
9494 and then Has_Completion
(Scope
(SE
))
9495 and then not Inside_Init_Proc
9497 -- If the type whose length is needed is a private component
9498 -- constrained by a discriminant, we must expand the 'Length
9499 -- attribute into an explicit computation, using the discriminal
9500 -- of the current protected operation. This is because the actual
9501 -- type of the prival is constructed after the protected opera-
9502 -- tion has been fully expanded.
9505 Indx_Type
: Node_Id
;
9508 Do_Expand
: Boolean := False;
9511 Indx_Type
:= First_Index
(E
);
9513 for J
in 1 .. Indx
- 1 loop
9514 Next_Index
(Indx_Type
);
9517 Get_Index_Bounds
(Indx_Type
, Lo
, Hi
);
9519 if Nkind
(Lo
) = N_Identifier
9520 and then Ekind
(Entity
(Lo
)) = E_In_Parameter
9522 Lo
:= Get_Discriminal
(E
, Lo
);
9526 if Nkind
(Hi
) = N_Identifier
9527 and then Ekind
(Entity
(Hi
)) = E_In_Parameter
9529 Hi
:= Get_Discriminal
(E
, Hi
);
9534 if not Is_Entity_Name
(Lo
) then
9535 Lo
:= Duplicate_Subexpr_No_Checks
(Lo
);
9538 if not Is_Entity_Name
(Hi
) then
9539 Lo
:= Duplicate_Subexpr_No_Checks
(Hi
);
9545 Make_Op_Subtract
(Loc
,
9549 Right_Opnd
=> Make_Integer_Literal
(Loc
, 1));
9554 Make_Attribute_Reference
(Loc
,
9555 Attribute_Name
=> Name_Length
,
9557 New_Occurrence_Of
(E1
, Loc
));
9560 Set_Expressions
(N
, New_List
(
9561 Make_Integer_Literal
(Loc
, Indx
)));
9570 Make_Attribute_Reference
(Loc
,
9571 Attribute_Name
=> Name_Length
,
9573 New_Occurrence_Of
(E1
, Loc
));
9576 Set_Expressions
(N
, New_List
(
9577 Make_Integer_Literal
(Loc
, Indx
)));
9588 function Get_N_Length
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
9591 Make_Attribute_Reference
(Loc
,
9592 Attribute_Name
=> Name_Length
,
9594 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
9595 Expressions
=> New_List
(
9596 Make_Integer_Literal
(Loc
, Indx
)));
9603 function Length_E_Cond
9604 (Exptyp
: Entity_Id
;
9606 Indx
: Nat
) return Node_Id
9611 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
9612 Right_Opnd
=> Get_E_Length
(Exptyp
, Indx
));
9619 function Length_N_Cond
9622 Indx
: Nat
) return Node_Id
9627 Left_Opnd
=> Get_E_Length
(Typ
, Indx
),
9628 Right_Opnd
=> Get_N_Length
(Expr
, Indx
));
9635 function Same_Bounds
(L
: Node_Id
; R
: Node_Id
) return Boolean is
9638 (Nkind
(L
) = N_Integer_Literal
9639 and then Nkind
(R
) = N_Integer_Literal
9640 and then Intval
(L
) = Intval
(R
))
9644 and then Ekind
(Entity
(L
)) = E_Constant
9645 and then ((Is_Entity_Name
(R
)
9646 and then Entity
(L
) = Entity
(R
))
9648 (Nkind
(R
) = N_Type_Conversion
9649 and then Is_Entity_Name
(Expression
(R
))
9650 and then Entity
(L
) = Entity
(Expression
(R
)))))
9654 and then Ekind
(Entity
(R
)) = E_Constant
9655 and then Nkind
(L
) = N_Type_Conversion
9656 and then Is_Entity_Name
(Expression
(L
))
9657 and then Entity
(R
) = Entity
(Expression
(L
)))
9661 and then Is_Entity_Name
(R
)
9662 and then Entity
(L
) = Entity
(R
)
9663 and then Ekind
(Entity
(L
)) = E_In_Parameter
9664 and then Inside_Init_Proc
);
9667 -- Start of processing for Selected_Length_Checks
9670 -- Checks will be applied only when generating code
9672 if not Expander_Active
then
9676 if Target_Typ
= Any_Type
9677 or else Target_Typ
= Any_Composite
9678 or else Raises_Constraint_Error
(Ck_Node
)
9687 T_Typ
:= Target_Typ
;
9689 if No
(Source_Typ
) then
9690 S_Typ
:= Etype
(Ck_Node
);
9692 S_Typ
:= Source_Typ
;
9695 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
9699 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
9700 S_Typ
:= Designated_Type
(S_Typ
);
9701 T_Typ
:= Designated_Type
(T_Typ
);
9704 -- A simple optimization for the null case
9706 if Known_Null
(Ck_Node
) then
9711 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
9712 if Is_Constrained
(T_Typ
) then
9714 -- The checking code to be generated will freeze the corresponding
9715 -- array type. However, we must freeze the type now, so that the
9716 -- freeze node does not appear within the generated if expression,
9719 Freeze_Before
(Ck_Node
, T_Typ
);
9721 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
9722 Exptyp
:= Get_Actual_Subtype
(Ck_Node
);
9724 if Is_Access_Type
(Exptyp
) then
9725 Exptyp
:= Designated_Type
(Exptyp
);
9728 -- String_Literal case. This needs to be handled specially be-
9729 -- cause no index types are available for string literals. The
9730 -- condition is simply:
9732 -- T_Typ'Length = string-literal-length
9734 if Nkind
(Expr_Actual
) = N_String_Literal
9735 and then Ekind
(Etype
(Expr_Actual
)) = E_String_Literal_Subtype
9739 Left_Opnd
=> Get_E_Length
(T_Typ
, 1),
9741 Make_Integer_Literal
(Loc
,
9743 String_Literal_Length
(Etype
(Expr_Actual
))));
9745 -- General array case. Here we have a usable actual subtype for
9746 -- the expression, and the condition is built from the two types
9749 -- T_Typ'Length /= Exptyp'Length or else
9750 -- T_Typ'Length (2) /= Exptyp'Length (2) or else
9751 -- T_Typ'Length (3) /= Exptyp'Length (3) or else
9754 elsif Is_Constrained
(Exptyp
) then
9756 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
9769 -- At the library level, we need to ensure that the type of
9770 -- the object is elaborated before the check itself is
9771 -- emitted. This is only done if the object is in the
9772 -- current compilation unit, otherwise the type is frozen
9773 -- and elaborated in its unit.
9775 if Is_Itype
(Exptyp
)
9777 Ekind
(Cunit_Entity
(Current_Sem_Unit
)) = E_Package
9779 not In_Package_Body
(Cunit_Entity
(Current_Sem_Unit
))
9780 and then In_Open_Scopes
(Scope
(Exptyp
))
9782 Ref_Node
:= Make_Itype_Reference
(Sloc
(Ck_Node
));
9783 Set_Itype
(Ref_Node
, Exptyp
);
9784 Insert_Action
(Ck_Node
, Ref_Node
);
9787 L_Index
:= First_Index
(T_Typ
);
9788 R_Index
:= First_Index
(Exptyp
);
9790 for Indx
in 1 .. Ndims
loop
9791 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
9793 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
9795 Get_Index_Bounds
(L_Index
, L_Low
, L_High
);
9796 Get_Index_Bounds
(R_Index
, R_Low
, R_High
);
9798 -- Deal with compile time length check. Note that we
9799 -- skip this in the access case, because the access
9800 -- value may be null, so we cannot know statically.
9803 and then Compile_Time_Known_Value
(L_Low
)
9804 and then Compile_Time_Known_Value
(L_High
)
9805 and then Compile_Time_Known_Value
(R_Low
)
9806 and then Compile_Time_Known_Value
(R_High
)
9808 if Expr_Value
(L_High
) >= Expr_Value
(L_Low
) then
9809 L_Length
:= Expr_Value
(L_High
) -
9810 Expr_Value
(L_Low
) + 1;
9812 L_Length
:= UI_From_Int
(0);
9815 if Expr_Value
(R_High
) >= Expr_Value
(R_Low
) then
9816 R_Length
:= Expr_Value
(R_High
) -
9817 Expr_Value
(R_Low
) + 1;
9819 R_Length
:= UI_From_Int
(0);
9822 if L_Length
> R_Length
then
9824 (Compile_Time_Constraint_Error
9825 (Wnode
, "too few elements for}??", T_Typ
));
9827 elsif L_Length
< R_Length
then
9829 (Compile_Time_Constraint_Error
9830 (Wnode
, "too many elements for}??", T_Typ
));
9833 -- The comparison for an individual index subtype
9834 -- is omitted if the corresponding index subtypes
9835 -- statically match, since the result is known to
9836 -- be true. Note that this test is worth while even
9837 -- though we do static evaluation, because non-static
9838 -- subtypes can statically match.
9841 Subtypes_Statically_Match
9842 (Etype
(L_Index
), Etype
(R_Index
))
9845 (Same_Bounds
(L_Low
, R_Low
)
9846 and then Same_Bounds
(L_High
, R_High
))
9849 (Cond
, Length_E_Cond
(Exptyp
, T_Typ
, Indx
));
9858 -- Handle cases where we do not get a usable actual subtype that
9859 -- is constrained. This happens for example in the function call
9860 -- and explicit dereference cases. In these cases, we have to get
9861 -- the length or range from the expression itself, making sure we
9862 -- do not evaluate it more than once.
9864 -- Here Ck_Node is the original expression, or more properly the
9865 -- result of applying Duplicate_Expr to the original tree, forcing
9866 -- the result to be a name.
9870 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
9873 -- Build the condition for the explicit dereference case
9875 for Indx
in 1 .. Ndims
loop
9877 (Cond
, Length_N_Cond
(Ck_Node
, T_Typ
, Indx
));
9884 -- Construct the test and insert into the tree
9886 if Present
(Cond
) then
9888 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
9892 (Make_Raise_Constraint_Error
(Loc
,
9894 Reason
=> CE_Length_Check_Failed
));
9898 end Selected_Length_Checks
;
9900 ---------------------------
9901 -- Selected_Range_Checks --
9902 ---------------------------
9904 function Selected_Range_Checks
9906 Target_Typ
: Entity_Id
;
9907 Source_Typ
: Entity_Id
;
9908 Warn_Node
: Node_Id
) return Check_Result
9910 Loc
: constant Source_Ptr
:= Sloc
(Ck_Node
);
9913 Expr_Actual
: Node_Id
;
9915 Cond
: Node_Id
:= Empty
;
9916 Do_Access
: Boolean := False;
9917 Wnode
: Node_Id
:= Warn_Node
;
9918 Ret_Result
: Check_Result
:= (Empty
, Empty
);
9919 Num_Checks
: Natural := 0;
9921 procedure Add_Check
(N
: Node_Id
);
9922 -- Adds the action given to Ret_Result if N is non-Empty
9924 function Discrete_Range_Cond
9926 Typ
: Entity_Id
) return Node_Id
;
9927 -- Returns expression to compute:
9928 -- Low_Bound (Expr) < Typ'First
9930 -- High_Bound (Expr) > Typ'Last
9932 function Discrete_Expr_Cond
9934 Typ
: Entity_Id
) return Node_Id
;
9935 -- Returns expression to compute:
9940 function Get_E_First_Or_Last
9944 Nam
: Name_Id
) return Node_Id
;
9945 -- Returns an attribute reference
9946 -- E'First or E'Last
9947 -- with a source location of Loc.
9949 -- Nam is Name_First or Name_Last, according to which attribute is
9950 -- desired. If Indx is non-zero, it is passed as a literal in the
9951 -- Expressions of the attribute reference (identifying the desired
9952 -- array dimension).
9954 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
9955 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
;
9956 -- Returns expression to compute:
9957 -- N'First or N'Last using Duplicate_Subexpr_No_Checks
9959 function Range_E_Cond
9960 (Exptyp
: Entity_Id
;
9964 -- Returns expression to compute:
9965 -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
9967 function Range_Equal_E_Cond
9968 (Exptyp
: Entity_Id
;
9970 Indx
: Nat
) return Node_Id
;
9971 -- Returns expression to compute:
9972 -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
9974 function Range_N_Cond
9977 Indx
: Nat
) return Node_Id
;
9978 -- Return expression to compute:
9979 -- Expr'First < Typ'First or else Expr'Last > Typ'Last
9985 procedure Add_Check
(N
: Node_Id
) is
9989 -- For now, ignore attempt to place more than 2 checks ???
9991 if Num_Checks
= 2 then
9995 pragma Assert
(Num_Checks
<= 1);
9996 Num_Checks
:= Num_Checks
+ 1;
9997 Ret_Result
(Num_Checks
) := N
;
10001 -------------------------
10002 -- Discrete_Expr_Cond --
10003 -------------------------
10005 function Discrete_Expr_Cond
10007 Typ
: Entity_Id
) return Node_Id
10015 Convert_To
(Base_Type
(Typ
),
10016 Duplicate_Subexpr_No_Checks
(Expr
)),
10018 Convert_To
(Base_Type
(Typ
),
10019 Get_E_First_Or_Last
(Loc
, Typ
, 0, Name_First
))),
10024 Convert_To
(Base_Type
(Typ
),
10025 Duplicate_Subexpr_No_Checks
(Expr
)),
10029 Get_E_First_Or_Last
(Loc
, Typ
, 0, Name_Last
))));
10030 end Discrete_Expr_Cond
;
10032 -------------------------
10033 -- Discrete_Range_Cond --
10034 -------------------------
10036 function Discrete_Range_Cond
10038 Typ
: Entity_Id
) return Node_Id
10040 LB
: Node_Id
:= Low_Bound
(Expr
);
10041 HB
: Node_Id
:= High_Bound
(Expr
);
10043 Left_Opnd
: Node_Id
;
10044 Right_Opnd
: Node_Id
;
10047 if Nkind
(LB
) = N_Identifier
10048 and then Ekind
(Entity
(LB
)) = E_Discriminant
10050 LB
:= New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
10057 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(LB
)),
10062 Get_E_First_Or_Last
(Loc
, Typ
, 0, Name_First
)));
10064 if Nkind
(HB
) = N_Identifier
10065 and then Ekind
(Entity
(HB
)) = E_Discriminant
10067 HB
:= New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
10074 (Base_Type
(Typ
), Duplicate_Subexpr_No_Checks
(HB
)),
10079 Get_E_First_Or_Last
(Loc
, Typ
, 0, Name_Last
)));
10081 return Make_Or_Else
(Loc
, Left_Opnd
, Right_Opnd
);
10082 end Discrete_Range_Cond
;
10084 -------------------------
10085 -- Get_E_First_Or_Last --
10086 -------------------------
10088 function Get_E_First_Or_Last
10092 Nam
: Name_Id
) return Node_Id
10097 Exprs
:= New_List
(Make_Integer_Literal
(Loc
, UI_From_Int
(Indx
)));
10102 return Make_Attribute_Reference
(Loc
,
10103 Prefix
=> New_Occurrence_Of
(E
, Loc
),
10104 Attribute_Name
=> Nam
,
10105 Expressions
=> Exprs
);
10106 end Get_E_First_Or_Last
;
10112 function Get_N_First
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
10115 Make_Attribute_Reference
(Loc
,
10116 Attribute_Name
=> Name_First
,
10118 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
10119 Expressions
=> New_List
(
10120 Make_Integer_Literal
(Loc
, Indx
)));
10127 function Get_N_Last
(N
: Node_Id
; Indx
: Nat
) return Node_Id
is
10130 Make_Attribute_Reference
(Loc
,
10131 Attribute_Name
=> Name_Last
,
10133 Duplicate_Subexpr_No_Checks
(N
, Name_Req
=> True),
10134 Expressions
=> New_List
(
10135 Make_Integer_Literal
(Loc
, Indx
)));
10142 function Range_E_Cond
10143 (Exptyp
: Entity_Id
;
10145 Indx
: Nat
) return Node_Id
10153 Get_E_First_Or_Last
(Loc
, Exptyp
, Indx
, Name_First
),
10155 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_First
)),
10160 Get_E_First_Or_Last
(Loc
, Exptyp
, Indx
, Name_Last
),
10162 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_Last
)));
10165 ------------------------
10166 -- Range_Equal_E_Cond --
10167 ------------------------
10169 function Range_Equal_E_Cond
10170 (Exptyp
: Entity_Id
;
10172 Indx
: Nat
) return Node_Id
10180 Get_E_First_Or_Last
(Loc
, Exptyp
, Indx
, Name_First
),
10182 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_First
)),
10187 Get_E_First_Or_Last
(Loc
, Exptyp
, Indx
, Name_Last
),
10189 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_Last
)));
10190 end Range_Equal_E_Cond
;
10196 function Range_N_Cond
10199 Indx
: Nat
) return Node_Id
10207 Get_N_First
(Expr
, Indx
),
10209 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_First
)),
10214 Get_N_Last
(Expr
, Indx
),
10216 Get_E_First_Or_Last
(Loc
, Typ
, Indx
, Name_Last
)));
10219 -- Start of processing for Selected_Range_Checks
10222 -- Checks will be applied only when generating code. In GNATprove mode,
10223 -- we do not apply the checks, but we still call Selected_Range_Checks
10224 -- to possibly issue errors on SPARK code when a run-time error can be
10225 -- detected at compile time.
10227 if not Expander_Active
and not GNATprove_Mode
then
10231 if Target_Typ
= Any_Type
10232 or else Target_Typ
= Any_Composite
10233 or else Raises_Constraint_Error
(Ck_Node
)
10242 T_Typ
:= Target_Typ
;
10244 if No
(Source_Typ
) then
10245 S_Typ
:= Etype
(Ck_Node
);
10247 S_Typ
:= Source_Typ
;
10250 if S_Typ
= Any_Type
or else S_Typ
= Any_Composite
then
10254 -- The order of evaluating T_Typ before S_Typ seems to be critical
10255 -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
10256 -- in, and since Node can be an N_Range node, it might be invalid.
10257 -- Should there be an assert check somewhere for taking the Etype of
10258 -- an N_Range node ???
10260 if Is_Access_Type
(T_Typ
) and then Is_Access_Type
(S_Typ
) then
10261 S_Typ
:= Designated_Type
(S_Typ
);
10262 T_Typ
:= Designated_Type
(T_Typ
);
10265 -- A simple optimization for the null case
10267 if Known_Null
(Ck_Node
) then
10272 -- For an N_Range Node, check for a null range and then if not
10273 -- null generate a range check action.
10275 if Nkind
(Ck_Node
) = N_Range
then
10277 -- There's no point in checking a range against itself
10279 if Ck_Node
= Scalar_Range
(T_Typ
) then
10284 T_LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
10285 T_HB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
10286 Known_T_LB
: constant Boolean := Compile_Time_Known_Value
(T_LB
);
10287 Known_T_HB
: constant Boolean := Compile_Time_Known_Value
(T_HB
);
10289 LB
: Node_Id
:= Low_Bound
(Ck_Node
);
10290 HB
: Node_Id
:= High_Bound
(Ck_Node
);
10291 Known_LB
: Boolean := False;
10292 Known_HB
: Boolean := False;
10294 Null_Range
: Boolean;
10295 Out_Of_Range_L
: Boolean;
10296 Out_Of_Range_H
: Boolean;
10299 -- Compute what is known at compile time
10301 if Known_T_LB
and Known_T_HB
then
10302 if Compile_Time_Known_Value
(LB
) then
10305 -- There's no point in checking that a bound is within its
10306 -- own range so pretend that it is known in this case. First
10307 -- deal with low bound.
10309 elsif Ekind
(Etype
(LB
)) = E_Signed_Integer_Subtype
10310 and then Scalar_Range
(Etype
(LB
)) = Scalar_Range
(T_Typ
)
10316 -- Likewise for the high bound
10318 if Compile_Time_Known_Value
(HB
) then
10321 elsif Ekind
(Etype
(HB
)) = E_Signed_Integer_Subtype
10322 and then Scalar_Range
(Etype
(HB
)) = Scalar_Range
(T_Typ
)
10329 -- Check for case where everything is static and we can do the
10330 -- check at compile time. This is skipped if we have an access
10331 -- type, since the access value may be null.
10333 -- ??? This code can be improved since you only need to know that
10334 -- the two respective bounds (LB & T_LB or HB & T_HB) are known at
10335 -- compile time to emit pertinent messages.
10337 if Known_T_LB
and Known_T_HB
and Known_LB
and Known_HB
10340 -- Floating-point case
10342 if Is_Floating_Point_Type
(S_Typ
) then
10343 Null_Range
:= Expr_Value_R
(HB
) < Expr_Value_R
(LB
);
10345 (Expr_Value_R
(LB
) < Expr_Value_R
(T_LB
))
10347 (Expr_Value_R
(LB
) > Expr_Value_R
(T_HB
));
10350 (Expr_Value_R
(HB
) > Expr_Value_R
(T_HB
))
10352 (Expr_Value_R
(HB
) < Expr_Value_R
(T_LB
));
10354 -- Fixed or discrete type case
10357 Null_Range
:= Expr_Value
(HB
) < Expr_Value
(LB
);
10359 (Expr_Value
(LB
) < Expr_Value
(T_LB
))
10361 (Expr_Value
(LB
) > Expr_Value
(T_HB
));
10364 (Expr_Value
(HB
) > Expr_Value
(T_HB
))
10366 (Expr_Value
(HB
) < Expr_Value
(T_LB
));
10369 if not Null_Range
then
10370 if Out_Of_Range_L
then
10371 if No
(Warn_Node
) then
10373 (Compile_Time_Constraint_Error
10374 (Low_Bound
(Ck_Node
),
10375 "static value out of range of}??", T_Typ
));
10379 (Compile_Time_Constraint_Error
10381 "static range out of bounds of}??", T_Typ
));
10385 if Out_Of_Range_H
then
10386 if No
(Warn_Node
) then
10388 (Compile_Time_Constraint_Error
10389 (High_Bound
(Ck_Node
),
10390 "static value out of range of}??", T_Typ
));
10394 (Compile_Time_Constraint_Error
10396 "static range out of bounds of}??", T_Typ
));
10403 LB
: Node_Id
:= Low_Bound
(Ck_Node
);
10404 HB
: Node_Id
:= High_Bound
(Ck_Node
);
10407 -- If either bound is a discriminant and we are within the
10408 -- record declaration, it is a use of the discriminant in a
10409 -- constraint of a component, and nothing can be checked
10410 -- here. The check will be emitted within the init proc.
10411 -- Before then, the discriminal has no real meaning.
10412 -- Similarly, if the entity is a discriminal, there is no
10413 -- check to perform yet.
10415 -- The same holds within a discriminated synchronized type,
10416 -- where the discriminant may constrain a component or an
10419 if Nkind
(LB
) = N_Identifier
10420 and then Denotes_Discriminant
(LB
, True)
10422 if Current_Scope
= Scope
(Entity
(LB
))
10423 or else Is_Concurrent_Type
(Current_Scope
)
10424 or else Ekind
(Entity
(LB
)) /= E_Discriminant
10429 New_Occurrence_Of
(Discriminal
(Entity
(LB
)), Loc
);
10433 if Nkind
(HB
) = N_Identifier
10434 and then Denotes_Discriminant
(HB
, True)
10436 if Current_Scope
= Scope
(Entity
(HB
))
10437 or else Is_Concurrent_Type
(Current_Scope
)
10438 or else Ekind
(Entity
(HB
)) /= E_Discriminant
10443 New_Occurrence_Of
(Discriminal
(Entity
(HB
)), Loc
);
10447 Cond
:= Discrete_Range_Cond
(Ck_Node
, T_Typ
);
10448 Set_Paren_Count
(Cond
, 1);
10451 Make_And_Then
(Loc
,
10455 Convert_To
(Base_Type
(Etype
(HB
)),
10456 Duplicate_Subexpr_No_Checks
(HB
)),
10458 Convert_To
(Base_Type
(Etype
(LB
)),
10459 Duplicate_Subexpr_No_Checks
(LB
))),
10460 Right_Opnd
=> Cond
);
10465 elsif Is_Scalar_Type
(S_Typ
) then
10467 -- This somewhat duplicates what Apply_Scalar_Range_Check does,
10468 -- except the above simply sets a flag in the node and lets
10469 -- gigi generate the check base on the Etype of the expression.
10470 -- Sometimes, however we want to do a dynamic check against an
10471 -- arbitrary target type, so we do that here.
10473 if Ekind
(Base_Type
(S_Typ
)) /= Ekind
(Base_Type
(T_Typ
)) then
10474 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
10476 -- For literals, we can tell if the constraint error will be
10477 -- raised at compile time, so we never need a dynamic check, but
10478 -- if the exception will be raised, then post the usual warning,
10479 -- and replace the literal with a raise constraint error
10480 -- expression. As usual, skip this for access types
10482 elsif Compile_Time_Known_Value
(Ck_Node
) and then not Do_Access
then
10484 LB
: constant Node_Id
:= Type_Low_Bound
(T_Typ
);
10485 UB
: constant Node_Id
:= Type_High_Bound
(T_Typ
);
10487 Out_Of_Range
: Boolean;
10488 Static_Bounds
: constant Boolean :=
10489 Compile_Time_Known_Value
(LB
)
10490 and Compile_Time_Known_Value
(UB
);
10493 -- Following range tests should use Sem_Eval routine ???
10495 if Static_Bounds
then
10496 if Is_Floating_Point_Type
(S_Typ
) then
10498 (Expr_Value_R
(Ck_Node
) < Expr_Value_R
(LB
))
10500 (Expr_Value_R
(Ck_Node
) > Expr_Value_R
(UB
));
10502 -- Fixed or discrete type
10506 Expr_Value
(Ck_Node
) < Expr_Value
(LB
)
10508 Expr_Value
(Ck_Node
) > Expr_Value
(UB
);
10511 -- Bounds of the type are static and the literal is out of
10512 -- range so output a warning message.
10514 if Out_Of_Range
then
10515 if No
(Warn_Node
) then
10517 (Compile_Time_Constraint_Error
10519 "static value out of range of}??", T_Typ
));
10523 (Compile_Time_Constraint_Error
10525 "static value out of range of}??", T_Typ
));
10530 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
10534 -- Here for the case of a non-static expression, we need a runtime
10535 -- check unless the source type range is guaranteed to be in the
10536 -- range of the target type.
10539 if not In_Subrange_Of
(S_Typ
, T_Typ
) then
10540 Cond
:= Discrete_Expr_Cond
(Ck_Node
, T_Typ
);
10545 if Is_Array_Type
(T_Typ
) and then Is_Array_Type
(S_Typ
) then
10546 if Is_Constrained
(T_Typ
) then
10548 Expr_Actual
:= Get_Referenced_Object
(Ck_Node
);
10549 Exptyp
:= Get_Actual_Subtype
(Expr_Actual
);
10551 if Is_Access_Type
(Exptyp
) then
10552 Exptyp
:= Designated_Type
(Exptyp
);
10555 -- String_Literal case. This needs to be handled specially be-
10556 -- cause no index types are available for string literals. The
10557 -- condition is simply:
10559 -- T_Typ'Length = string-literal-length
10561 if Nkind
(Expr_Actual
) = N_String_Literal
then
10564 -- General array case. Here we have a usable actual subtype for
10565 -- the expression, and the condition is built from the two types
10567 -- T_Typ'First < Exptyp'First or else
10568 -- T_Typ'Last > Exptyp'Last or else
10569 -- T_Typ'First(1) < Exptyp'First(1) or else
10570 -- T_Typ'Last(1) > Exptyp'Last(1) or else
10573 elsif Is_Constrained
(Exptyp
) then
10575 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
10581 L_Index
:= First_Index
(T_Typ
);
10582 R_Index
:= First_Index
(Exptyp
);
10584 for Indx
in 1 .. Ndims
loop
10585 if not (Nkind
(L_Index
) = N_Raise_Constraint_Error
10587 Nkind
(R_Index
) = N_Raise_Constraint_Error
)
10589 -- Deal with compile time length check. Note that we
10590 -- skip this in the access case, because the access
10591 -- value may be null, so we cannot know statically.
10594 Subtypes_Statically_Match
10595 (Etype
(L_Index
), Etype
(R_Index
))
10597 -- If the target type is constrained then we
10598 -- have to check for exact equality of bounds
10599 -- (required for qualified expressions).
10601 if Is_Constrained
(T_Typ
) then
10604 Range_Equal_E_Cond
(Exptyp
, T_Typ
, Indx
));
10607 (Cond
, Range_E_Cond
(Exptyp
, T_Typ
, Indx
));
10617 -- Handle cases where we do not get a usable actual subtype that
10618 -- is constrained. This happens for example in the function call
10619 -- and explicit dereference cases. In these cases, we have to get
10620 -- the length or range from the expression itself, making sure we
10621 -- do not evaluate it more than once.
10623 -- Here Ck_Node is the original expression, or more properly the
10624 -- result of applying Duplicate_Expr to the original tree,
10625 -- forcing the result to be a name.
10629 Ndims
: constant Nat
:= Number_Dimensions
(T_Typ
);
10632 -- Build the condition for the explicit dereference case
10634 for Indx
in 1 .. Ndims
loop
10636 (Cond
, Range_N_Cond
(Ck_Node
, T_Typ
, Indx
));
10642 -- For a conversion to an unconstrained array type, generate an
10643 -- Action to check that the bounds of the source value are within
10644 -- the constraints imposed by the target type (RM 4.6(38)). No
10645 -- check is needed for a conversion to an access to unconstrained
10646 -- array type, as 4.6(24.15/2) requires the designated subtypes
10647 -- of the two access types to statically match.
10649 if Nkind
(Parent
(Ck_Node
)) = N_Type_Conversion
10650 and then not Do_Access
10653 Opnd_Index
: Node_Id
;
10654 Targ_Index
: Node_Id
;
10655 Opnd_Range
: Node_Id
;
10658 Opnd_Index
:= First_Index
(Get_Actual_Subtype
(Ck_Node
));
10659 Targ_Index
:= First_Index
(T_Typ
);
10660 while Present
(Opnd_Index
) loop
10662 -- If the index is a range, use its bounds. If it is an
10663 -- entity (as will be the case if it is a named subtype
10664 -- or an itype created for a slice) retrieve its range.
10666 if Is_Entity_Name
(Opnd_Index
)
10667 and then Is_Type
(Entity
(Opnd_Index
))
10669 Opnd_Range
:= Scalar_Range
(Entity
(Opnd_Index
));
10671 Opnd_Range
:= Opnd_Index
;
10674 if Nkind
(Opnd_Range
) = N_Range
then
10676 (Low_Bound
(Opnd_Range
), Etype
(Targ_Index
),
10677 Assume_Valid
=> True)
10680 (High_Bound
(Opnd_Range
), Etype
(Targ_Index
),
10681 Assume_Valid
=> True)
10685 -- If null range, no check needed
10688 Compile_Time_Known_Value
(High_Bound
(Opnd_Range
))
10690 Compile_Time_Known_Value
(Low_Bound
(Opnd_Range
))
10692 Expr_Value
(High_Bound
(Opnd_Range
)) <
10693 Expr_Value
(Low_Bound
(Opnd_Range
))
10697 elsif Is_Out_Of_Range
10698 (Low_Bound
(Opnd_Range
), Etype
(Targ_Index
),
10699 Assume_Valid
=> True)
10702 (High_Bound
(Opnd_Range
), Etype
(Targ_Index
),
10703 Assume_Valid
=> True)
10706 (Compile_Time_Constraint_Error
10707 (Wnode
, "value out of range of}??", T_Typ
));
10712 Discrete_Range_Cond
10713 (Opnd_Range
, Etype
(Targ_Index
)));
10717 Next_Index
(Opnd_Index
);
10718 Next_Index
(Targ_Index
);
10725 -- Construct the test and insert into the tree
10727 if Present
(Cond
) then
10729 Cond
:= Guard_Access
(Cond
, Loc
, Ck_Node
);
10733 (Make_Raise_Constraint_Error
(Loc
,
10735 Reason
=> CE_Range_Check_Failed
));
10739 end Selected_Range_Checks
;
10741 -------------------------------
10742 -- Storage_Checks_Suppressed --
10743 -------------------------------
10745 function Storage_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
10747 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
10748 return Is_Check_Suppressed
(E
, Storage_Check
);
10750 return Scope_Suppress
.Suppress
(Storage_Check
);
10752 end Storage_Checks_Suppressed
;
10754 ---------------------------
10755 -- Tag_Checks_Suppressed --
10756 ---------------------------
10758 function Tag_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
10761 and then Checks_May_Be_Suppressed
(E
)
10763 return Is_Check_Suppressed
(E
, Tag_Check
);
10765 return Scope_Suppress
.Suppress
(Tag_Check
);
10767 end Tag_Checks_Suppressed
;
10769 ---------------------------------------
10770 -- Validate_Alignment_Check_Warnings --
10771 ---------------------------------------
10773 procedure Validate_Alignment_Check_Warnings
is
10775 for J
in Alignment_Warnings
.First
.. Alignment_Warnings
.Last
loop
10777 AWR
: Alignment_Warnings_Record
10778 renames Alignment_Warnings
.Table
(J
);
10780 if Known_Alignment
(AWR
.E
)
10781 and then AWR
.A
mod Alignment
(AWR
.E
) = 0
10783 Delete_Warning_And_Continuations
(AWR
.W
);
10787 end Validate_Alignment_Check_Warnings
;
10789 --------------------------
10790 -- Validity_Check_Range --
10791 --------------------------
10793 procedure Validity_Check_Range
10795 Related_Id
: Entity_Id
:= Empty
)
10798 if Validity_Checks_On
and Validity_Check_Operands
then
10799 if Nkind
(N
) = N_Range
then
10801 (Expr
=> Low_Bound
(N
),
10802 Related_Id
=> Related_Id
,
10803 Is_Low_Bound
=> True);
10806 (Expr
=> High_Bound
(N
),
10807 Related_Id
=> Related_Id
,
10808 Is_High_Bound
=> True);
10811 end Validity_Check_Range
;
10813 --------------------------------
10814 -- Validity_Checks_Suppressed --
10815 --------------------------------
10817 function Validity_Checks_Suppressed
(E
: Entity_Id
) return Boolean is
10819 if Present
(E
) and then Checks_May_Be_Suppressed
(E
) then
10820 return Is_Check_Suppressed
(E
, Validity_Check
);
10822 return Scope_Suppress
.Suppress
(Validity_Check
);
10824 end Validity_Checks_Suppressed
;