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 Aspects
; use Aspects
;
27 with Atree
; use Atree
;
28 with Checks
; use Checks
;
29 with Debug
; use Debug
;
30 with Einfo
; use Einfo
;
31 with Elists
; use Elists
;
32 with Errout
; use Errout
;
33 with Eval_Fat
; use Eval_Fat
;
34 with Exp_Util
; use Exp_Util
;
35 with Freeze
; use Freeze
;
37 with Namet
; use Namet
;
38 with Nmake
; use Nmake
;
39 with Nlists
; use Nlists
;
41 with Par_SCO
; use Par_SCO
;
42 with Rtsfind
; use Rtsfind
;
44 with Sem_Aux
; use Sem_Aux
;
45 with Sem_Cat
; use Sem_Cat
;
46 with Sem_Ch6
; use Sem_Ch6
;
47 with Sem_Ch8
; use Sem_Ch8
;
48 with Sem_Res
; use Sem_Res
;
49 with Sem_Util
; use Sem_Util
;
50 with Sem_Type
; use Sem_Type
;
51 with Sem_Warn
; use Sem_Warn
;
52 with Sinfo
; use Sinfo
;
53 with Snames
; use Snames
;
54 with Stand
; use Stand
;
55 with Stringt
; use Stringt
;
56 with Tbuild
; use Tbuild
;
58 package body Sem_Eval
is
60 -----------------------------------------
61 -- Handling of Compile Time Evaluation --
62 -----------------------------------------
64 -- The compile time evaluation of expressions is distributed over several
65 -- Eval_xxx procedures. These procedures are called immediately after
66 -- a subexpression is resolved and is therefore accomplished in a bottom
67 -- up fashion. The flags are synthesized using the following approach.
69 -- Is_Static_Expression is determined by following the detailed rules
70 -- in RM 4.9(4-14). This involves testing the Is_Static_Expression
71 -- flag of the operands in many cases.
73 -- Raises_Constraint_Error is set if any of the operands have the flag
74 -- set or if an attempt to compute the value of the current expression
75 -- results in detection of a runtime constraint error.
77 -- As described in the spec, the requirement is that Is_Static_Expression
78 -- be accurately set, and in addition for nodes for which this flag is set,
79 -- Raises_Constraint_Error must also be set. Furthermore a node which has
80 -- Is_Static_Expression set, and Raises_Constraint_Error clear, then the
81 -- requirement is that the expression value must be precomputed, and the
82 -- node is either a literal, or the name of a constant entity whose value
83 -- is a static expression.
85 -- The general approach is as follows. First compute Is_Static_Expression.
86 -- If the node is not static, then the flag is left off in the node and
87 -- we are all done. Otherwise for a static node, we test if any of the
88 -- operands will raise constraint error, and if so, propagate the flag
89 -- Raises_Constraint_Error to the result node and we are done (since the
90 -- error was already posted at a lower level).
92 -- For the case of a static node whose operands do not raise constraint
93 -- error, we attempt to evaluate the node. If this evaluation succeeds,
94 -- then the node is replaced by the result of this computation. If the
95 -- evaluation raises constraint error, then we rewrite the node with
96 -- Apply_Compile_Time_Constraint_Error to raise the exception and also
97 -- to post appropriate error messages.
103 type Bits
is array (Nat
range <>) of Boolean;
104 -- Used to convert unsigned (modular) values for folding logical ops
106 -- The following declarations are used to maintain a cache of nodes that
107 -- have compile time known values. The cache is maintained only for
108 -- discrete types (the most common case), and is populated by calls to
109 -- Compile_Time_Known_Value and Expr_Value, but only used by Expr_Value
110 -- since it is possible for the status to change (in particular it is
111 -- possible for a node to get replaced by a constraint error node).
113 CV_Bits
: constant := 5;
114 -- Number of low order bits of Node_Id value used to reference entries
115 -- in the cache table.
117 CV_Cache_Size
: constant Nat
:= 2 ** CV_Bits
;
118 -- Size of cache for compile time values
120 subtype CV_Range
is Nat
range 0 .. CV_Cache_Size
;
122 type CV_Entry
is record
127 type Match_Result
is (Match
, No_Match
, Non_Static
);
128 -- Result returned from functions that test for a matching result. If the
129 -- operands are not OK_Static then Non_Static will be returned. Otherwise
130 -- Match/No_Match is returned depending on whether the match succeeds.
132 type CV_Cache_Array
is array (CV_Range
) of CV_Entry
;
134 CV_Cache
: CV_Cache_Array
:= (others => (Node_High_Bound
, Uint_0
));
135 -- This is the actual cache, with entries consisting of node/value pairs,
136 -- and the impossible value Node_High_Bound used for unset entries.
138 type Range_Membership
is (In_Range
, Out_Of_Range
, Unknown
);
139 -- Range membership may either be statically known to be in range or out
140 -- of range, or not statically known. Used for Test_In_Range below.
142 -----------------------
143 -- Local Subprograms --
144 -----------------------
146 function Choice_Matches
148 Choice
: Node_Id
) return Match_Result
;
149 -- Determines whether given value Expr matches the given Choice. The Expr
150 -- can be of discrete, real, or string type and must be a compile time
151 -- known value (it is an error to make the call if these conditions are
152 -- not met). The choice can be a range, subtype name, subtype indication,
153 -- or expression. The returned result is Non_Static if Choice is not
154 -- OK_Static, otherwise either Match or No_Match is returned depending
155 -- on whether Choice matches Expr. This is used for case expression
156 -- alternatives, and also for membership tests. In each case, more
157 -- possibilities are tested than the syntax allows (e.g. membership allows
158 -- subtype indications and non-discrete types, and case allows an OTHERS
159 -- choice), but it does not matter, since we have already done a full
160 -- semantic and syntax check of the construct, so the extra possibilities
161 -- just will not arise for correct expressions.
163 -- Note: if Choice_Matches finds that a choice raises Constraint_Error, e.g
164 -- a reference to a type, one of whose bounds raises Constraint_Error, then
165 -- it also sets the Raises_Constraint_Error flag on the Choice itself.
167 function Choices_Match
169 Choices
: List_Id
) return Match_Result
;
170 -- This function applies Choice_Matches to each element of Choices. If the
171 -- result is No_Match, then it continues and checks the next element. If
172 -- the result is Match or Non_Static, this result is immediately given
173 -- as the result without checking the rest of the list. Expr can be of
174 -- discrete, real, or string type and must be a compile time known value
175 -- (it is an error to make the call if these conditions are not met).
177 function Find_Universal_Operator_Type
(N
: Node_Id
) return Entity_Id
;
178 -- Check whether an arithmetic operation with universal operands which is a
179 -- rewritten function call with an explicit scope indication is ambiguous:
180 -- P."+" (1, 2) will be ambiguous if there is more than one visible numeric
181 -- type declared in P and the context does not impose a type on the result
182 -- (e.g. in the expression of a type conversion). If ambiguous, emit an
183 -- error and return Empty, else return the result type of the operator.
185 function From_Bits
(B
: Bits
; T
: Entity_Id
) return Uint
;
186 -- Converts a bit string of length B'Length to a Uint value to be used for
187 -- a target of type T, which is a modular type. This procedure includes the
188 -- necessary reduction by the modulus in the case of a nonbinary modulus
189 -- (for a binary modulus, the bit string is the right length any way so all
192 function Get_String_Val
(N
: Node_Id
) return Node_Id
;
193 -- Given a tree node for a folded string or character value, returns the
194 -- corresponding string literal or character literal (one of the two must
195 -- be available, or the operand would not have been marked as foldable in
196 -- the earlier analysis of the operation).
198 function Is_OK_Static_Choice
(Choice
: Node_Id
) return Boolean;
199 -- Given a choice (from a case expression or membership test), returns
200 -- True if the choice is static and does not raise a Constraint_Error.
202 function Is_OK_Static_Choice_List
(Choices
: List_Id
) return Boolean;
203 -- Given a choice list (from a case expression or membership test), return
204 -- True if all choices are static in the sense of Is_OK_Static_Choice.
206 function Is_Static_Choice
(Choice
: Node_Id
) return Boolean;
207 -- Given a choice (from a case expression or membership test), returns
208 -- True if the choice is static. No test is made for raising of constraint
209 -- error, so this function is used only for legality tests.
211 function Is_Static_Choice_List
(Choices
: List_Id
) return Boolean;
212 -- Given a choice list (from a case expression or membership test), return
213 -- True if all choices are static in the sense of Is_Static_Choice.
215 function Is_Static_Range
(N
: Node_Id
) return Boolean;
216 -- Determine if range is static, as defined in RM 4.9(26). The only allowed
217 -- argument is an N_Range node (but note that the semantic analysis of
218 -- equivalent range attribute references already turned them into the
219 -- equivalent range). This differs from Is_OK_Static_Range (which is what
220 -- must be used by clients) in that it does not care whether the bounds
221 -- raise Constraint_Error or not. Used for checking whether expressions are
222 -- static in the 4.9 sense (without worrying about exceptions).
224 function OK_Bits
(N
: Node_Id
; Bits
: Uint
) return Boolean;
225 -- Bits represents the number of bits in an integer value to be computed
226 -- (but the value has not been computed yet). If this value in Bits is
227 -- reasonable, a result of True is returned, with the implication that the
228 -- caller should go ahead and complete the calculation. If the value in
229 -- Bits is unreasonably large, then an error is posted on node N, and
230 -- False is returned (and the caller skips the proposed calculation).
232 procedure Out_Of_Range
(N
: Node_Id
);
233 -- This procedure is called if it is determined that node N, which appears
234 -- in a non-static context, is a compile time known value which is outside
235 -- its range, i.e. the range of Etype. This is used in contexts where
236 -- this is an illegality if N is static, and should generate a warning
239 function Real_Or_String_Static_Predicate_Matches
241 Typ
: Entity_Id
) return Boolean;
242 -- This is the function used to evaluate real or string static predicates.
243 -- Val is an unanalyzed N_Real_Literal or N_String_Literal node, which
244 -- represents the value to be tested against the predicate. Typ is the
245 -- type with the predicate, from which the predicate expression can be
246 -- extracted. The result returned is True if the given value satisfies
249 procedure Rewrite_In_Raise_CE
(N
: Node_Id
; Exp
: Node_Id
);
250 -- N and Exp are nodes representing an expression, Exp is known to raise
251 -- CE. N is rewritten in term of Exp in the optimal way.
253 function String_Type_Len
(Stype
: Entity_Id
) return Uint
;
254 -- Given a string type, determines the length of the index type, or, if
255 -- this index type is non-static, the length of the base type of this index
256 -- type. Note that if the string type is itself static, then the index type
257 -- is static, so the second case applies only if the string type passed is
260 function Test
(Cond
: Boolean) return Uint
;
261 pragma Inline
(Test
);
262 -- This function simply returns the appropriate Boolean'Pos value
263 -- corresponding to the value of Cond as a universal integer. It is
264 -- used for producing the result of the static evaluation of the
267 procedure Test_Expression_Is_Foldable
272 -- Tests to see if expression N whose single operand is Op1 is foldable,
273 -- i.e. the operand value is known at compile time. If the operation is
274 -- foldable, then Fold is True on return, and Stat indicates whether the
275 -- result is static (i.e. the operand was static). Note that it is quite
276 -- possible for Fold to be True, and Stat to be False, since there are
277 -- cases in which we know the value of an operand even though it is not
278 -- technically static (e.g. the static lower bound of a range whose upper
279 -- bound is non-static).
281 -- If Stat is set False on return, then Test_Expression_Is_Foldable makes
282 -- a call to Check_Non_Static_Context on the operand. If Fold is False on
283 -- return, then all processing is complete, and the caller should return,
284 -- since there is nothing else to do.
286 -- If Stat is set True on return, then Is_Static_Expression is also set
287 -- true in node N. There are some cases where this is over-enthusiastic,
288 -- e.g. in the two operand case below, for string comparison, the result is
289 -- not static even though the two operands are static. In such cases, the
290 -- caller must reset the Is_Static_Expression flag in N.
292 -- If Fold and Stat are both set to False then this routine performs also
293 -- the following extra actions:
295 -- If either operand is Any_Type then propagate it to result to prevent
298 -- If some operand raises constraint error, then replace the node N
299 -- with the raise constraint error node. This replacement inherits the
300 -- Is_Static_Expression flag from the operands.
302 procedure Test_Expression_Is_Foldable
308 CRT_Safe
: Boolean := False);
309 -- Same processing, except applies to an expression N with two operands
310 -- Op1 and Op2. The result is static only if both operands are static. If
311 -- CRT_Safe is set True, then CRT_Safe_Compile_Time_Known_Value is used
312 -- for the tests that the two operands are known at compile time. See
313 -- spec of this routine for further details.
315 function Test_In_Range
318 Assume_Valid
: Boolean;
320 Int_Real
: Boolean) return Range_Membership
;
321 -- Common processing for Is_In_Range and Is_Out_Of_Range: Returns In_Range
322 -- or Out_Of_Range if it can be guaranteed at compile time that expression
323 -- N is known to be in or out of range of the subtype Typ. If not compile
324 -- time known, Unknown is returned. See documentation of Is_In_Range for
325 -- complete description of parameters.
327 procedure To_Bits
(U
: Uint
; B
: out Bits
);
328 -- Converts a Uint value to a bit string of length B'Length
330 -----------------------------------------------
331 -- Check_Expression_Against_Static_Predicate --
332 -----------------------------------------------
334 procedure Check_Expression_Against_Static_Predicate
339 -- Nothing to do if expression is not known at compile time, or the
340 -- type has no static predicate set (will be the case for all non-scalar
341 -- types, so no need to make a special test for that).
343 if not (Has_Static_Predicate
(Typ
)
344 and then Compile_Time_Known_Value
(Expr
))
349 -- Here we have a static predicate (note that it could have arisen from
350 -- an explicitly specified Dynamic_Predicate whose expression met the
351 -- rules for being predicate-static). If the expression is known at
352 -- compile time and obeys the predicate, then it is static and must be
353 -- labeled as such, which matters e.g. for case statements. The original
354 -- expression may be a type conversion of a variable with a known value,
355 -- which might otherwise not be marked static.
357 -- Case of real static predicate
359 if Is_Real_Type
(Typ
) then
360 if Real_Or_String_Static_Predicate_Matches
361 (Val
=> Make_Real_Literal
(Sloc
(Expr
), Expr_Value_R
(Expr
)),
364 Set_Is_Static_Expression
(Expr
);
368 -- Case of string static predicate
370 elsif Is_String_Type
(Typ
) then
371 if Real_Or_String_Static_Predicate_Matches
372 (Val
=> Expr_Value_S
(Expr
), Typ
=> Typ
)
374 Set_Is_Static_Expression
(Expr
);
378 -- Case of discrete static predicate
381 pragma Assert
(Is_Discrete_Type
(Typ
));
383 -- If static predicate matches, nothing to do
385 if Choices_Match
(Expr
, Static_Discrete_Predicate
(Typ
)) = Match
then
386 Set_Is_Static_Expression
(Expr
);
391 -- Here we know that the predicate will fail
393 -- Special case of static expression failing a predicate (other than one
394 -- that was explicitly specified with a Dynamic_Predicate aspect). This
395 -- is the case where the expression is no longer considered static.
397 if Is_Static_Expression
(Expr
)
398 and then not Has_Dynamic_Predicate_Aspect
(Typ
)
401 ("??static expression fails static predicate check on &",
404 ("\??expression is no longer considered static", Expr
);
405 Set_Is_Static_Expression
(Expr
, False);
407 -- In all other cases, this is just a warning that a test will fail.
408 -- It does not matter if the expression is static or not, or if the
409 -- predicate comes from a dynamic predicate aspect or not.
413 ("??expression fails predicate check on &", Expr
, Typ
);
415 end Check_Expression_Against_Static_Predicate
;
417 ------------------------------
418 -- Check_Non_Static_Context --
419 ------------------------------
421 procedure Check_Non_Static_Context
(N
: Node_Id
) is
422 T
: constant Entity_Id
:= Etype
(N
);
423 Checks_On
: constant Boolean :=
424 not Index_Checks_Suppressed
(T
)
425 and not Range_Checks_Suppressed
(T
);
428 -- Ignore cases of non-scalar types, error types, or universal real
429 -- types that have no usable bounds.
432 or else not Is_Scalar_Type
(T
)
433 or else T
= Universal_Fixed
434 or else T
= Universal_Real
439 -- At this stage we have a scalar type. If we have an expression that
440 -- raises CE, then we already issued a warning or error msg so there is
441 -- nothing more to be done in this routine.
443 if Raises_Constraint_Error
(N
) then
447 -- Now we have a scalar type which is not marked as raising a constraint
448 -- error exception. The main purpose of this routine is to deal with
449 -- static expressions appearing in a non-static context. That means
450 -- that if we do not have a static expression then there is not much
451 -- to do. The one case that we deal with here is that if we have a
452 -- floating-point value that is out of range, then we post a warning
453 -- that an infinity will result.
455 if not Is_Static_Expression
(N
) then
456 if Is_Floating_Point_Type
(T
) then
457 if Is_Out_Of_Range
(N
, Base_Type
(T
), Assume_Valid
=> True) then
459 ("??float value out of range, infinity will be generated", N
);
461 -- The literal may be the result of constant-folding of a non-
462 -- static subexpression of a larger expression (e.g. a conversion
463 -- of a non-static variable whose value happens to be known). At
464 -- this point we must reduce the value of the subexpression to a
465 -- machine number (RM 4.9 (38/2)).
467 elsif Nkind
(N
) = N_Real_Literal
468 and then Nkind
(Parent
(N
)) in N_Subexpr
470 Rewrite
(N
, New_Copy
(N
));
472 (N
, Machine
(Base_Type
(T
), Realval
(N
), Round_Even
, N
));
479 -- Here we have the case of outer level static expression of scalar
480 -- type, where the processing of this procedure is needed.
482 -- For real types, this is where we convert the value to a machine
483 -- number (see RM 4.9(38)). Also see ACVC test C490001. We should only
484 -- need to do this if the parent is a constant declaration, since in
485 -- other cases, gigi should do the necessary conversion correctly, but
486 -- experimentation shows that this is not the case on all machines, in
487 -- particular if we do not convert all literals to machine values in
488 -- non-static contexts, then ACVC test C490001 fails on Sparc/Solaris
491 -- This conversion is always done by GNATprove on real literals in
492 -- non-static expressions, by calling Check_Non_Static_Context from
493 -- gnat2why, as GNATprove cannot do the conversion later contrary
494 -- to gigi. The frontend computes the information about which
495 -- expressions are static, which is used by gnat2why to call
496 -- Check_Non_Static_Context on exactly those real literals that are
497 -- not subexpressions of static expressions.
499 if Nkind
(N
) = N_Real_Literal
500 and then not Is_Machine_Number
(N
)
501 and then not Is_Generic_Type
(Etype
(N
))
502 and then Etype
(N
) /= Universal_Real
504 -- Check that value is in bounds before converting to machine
505 -- number, so as not to lose case where value overflows in the
506 -- least significant bit or less. See B490001.
508 if Is_Out_Of_Range
(N
, Base_Type
(T
), Assume_Valid
=> True) then
513 -- Note: we have to copy the node, to avoid problems with conformance
514 -- of very similar numbers (see ACVC tests B4A010C and B63103A).
516 Rewrite
(N
, New_Copy
(N
));
518 if not Is_Floating_Point_Type
(T
) then
520 (N
, Corresponding_Integer_Value
(N
) * Small_Value
(T
));
522 elsif not UR_Is_Zero
(Realval
(N
)) then
524 -- Note: even though RM 4.9(38) specifies biased rounding, this
525 -- has been modified by AI-100 in order to prevent confusing
526 -- differences in rounding between static and non-static
527 -- expressions. AI-100 specifies that the effect of such rounding
528 -- is implementation dependent, and in GNAT we round to nearest
529 -- even to match the run-time behavior. Note that this applies
530 -- to floating point literals, not fixed points ones, even though
531 -- their compiler representation is also as a universal real.
534 (N
, Machine
(Base_Type
(T
), Realval
(N
), Round_Even
, N
));
535 Set_Is_Machine_Number
(N
);
540 -- Check for out of range universal integer. This is a non-static
541 -- context, so the integer value must be in range of the runtime
542 -- representation of universal integers.
544 -- We do this only within an expression, because that is the only
545 -- case in which non-static universal integer values can occur, and
546 -- furthermore, Check_Non_Static_Context is currently (incorrectly???)
547 -- called in contexts like the expression of a number declaration where
548 -- we certainly want to allow out of range values.
550 if Etype
(N
) = Universal_Integer
551 and then Nkind
(N
) = N_Integer_Literal
552 and then Nkind
(Parent
(N
)) in N_Subexpr
554 (Intval
(N
) < Expr_Value
(Type_Low_Bound
(Universal_Integer
))
556 Intval
(N
) > Expr_Value
(Type_High_Bound
(Universal_Integer
)))
558 Apply_Compile_Time_Constraint_Error
559 (N
, "non-static universal integer value out of range<<",
560 CE_Range_Check_Failed
);
562 -- Check out of range of base type
564 elsif Is_Out_Of_Range
(N
, Base_Type
(T
), Assume_Valid
=> True) then
567 -- Give warning if outside subtype (where one or both of the bounds of
568 -- the subtype is static). This warning is omitted if the expression
569 -- appears in a range that could be null (warnings are handled elsewhere
572 elsif T
/= Base_Type
(T
) and then Nkind
(Parent
(N
)) /= N_Range
then
573 if Is_In_Range
(N
, T
, Assume_Valid
=> True) then
576 elsif Is_Out_Of_Range
(N
, T
, Assume_Valid
=> True) then
578 -- Ignore out of range values for System.Priority in CodePeer
579 -- mode since the actual target compiler may provide a wider
582 if CodePeer_Mode
and then T
= RTE
(RE_Priority
) then
583 Set_Do_Range_Check
(N
, False);
585 Apply_Compile_Time_Constraint_Error
586 (N
, "value not in range of}<<", CE_Range_Check_Failed
);
590 Enable_Range_Check
(N
);
593 Set_Do_Range_Check
(N
, False);
596 end Check_Non_Static_Context
;
598 ---------------------------------
599 -- Check_String_Literal_Length --
600 ---------------------------------
602 procedure Check_String_Literal_Length
(N
: Node_Id
; Ttype
: Entity_Id
) is
604 if not Raises_Constraint_Error
(N
) and then Is_Constrained
(Ttype
) then
605 if UI_From_Int
(String_Length
(Strval
(N
))) /= String_Type_Len
(Ttype
)
607 Apply_Compile_Time_Constraint_Error
608 (N
, "string length wrong for}??",
609 CE_Length_Check_Failed
,
614 end Check_String_Literal_Length
;
620 function Choice_Matches
622 Choice
: Node_Id
) return Match_Result
624 Etyp
: constant Entity_Id
:= Etype
(Expr
);
630 pragma Assert
(Compile_Time_Known_Value
(Expr
));
631 pragma Assert
(Is_Scalar_Type
(Etyp
) or else Is_String_Type
(Etyp
));
633 if not Is_OK_Static_Choice
(Choice
) then
634 Set_Raises_Constraint_Error
(Choice
);
637 -- When the choice denotes a subtype with a static predictate, check the
638 -- expression against the predicate values. Different procedures apply
639 -- to discrete and non-discrete types.
641 elsif (Nkind
(Choice
) = N_Subtype_Indication
642 or else (Is_Entity_Name
(Choice
)
643 and then Is_Type
(Entity
(Choice
))))
644 and then Has_Predicates
(Etype
(Choice
))
645 and then Has_Static_Predicate
(Etype
(Choice
))
647 if Is_Discrete_Type
(Etype
(Choice
)) then
650 (Expr
, Static_Discrete_Predicate
(Etype
(Choice
)));
652 elsif Real_Or_String_Static_Predicate_Matches
(Expr
, Etype
(Choice
))
660 -- Discrete type case only
662 elsif Is_Discrete_Type
(Etyp
) then
663 Val
:= Expr_Value
(Expr
);
665 if Nkind
(Choice
) = N_Range
then
666 if Val
>= Expr_Value
(Low_Bound
(Choice
))
668 Val
<= Expr_Value
(High_Bound
(Choice
))
675 elsif Nkind
(Choice
) = N_Subtype_Indication
676 or else (Is_Entity_Name
(Choice
) and then Is_Type
(Entity
(Choice
)))
678 if Val
>= Expr_Value
(Type_Low_Bound
(Etype
(Choice
)))
680 Val
<= Expr_Value
(Type_High_Bound
(Etype
(Choice
)))
687 elsif Nkind
(Choice
) = N_Others_Choice
then
691 if Val
= Expr_Value
(Choice
) then
700 elsif Is_Real_Type
(Etyp
) then
701 ValR
:= Expr_Value_R
(Expr
);
703 if Nkind
(Choice
) = N_Range
then
704 if ValR
>= Expr_Value_R
(Low_Bound
(Choice
))
706 ValR
<= Expr_Value_R
(High_Bound
(Choice
))
713 elsif Nkind
(Choice
) = N_Subtype_Indication
714 or else (Is_Entity_Name
(Choice
) and then Is_Type
(Entity
(Choice
)))
716 if ValR
>= Expr_Value_R
(Type_Low_Bound
(Etype
(Choice
)))
718 ValR
<= Expr_Value_R
(Type_High_Bound
(Etype
(Choice
)))
726 if ValR
= Expr_Value_R
(Choice
) then
736 pragma Assert
(Is_String_Type
(Etyp
));
737 ValS
:= Expr_Value_S
(Expr
);
739 if Nkind
(Choice
) = N_Subtype_Indication
740 or else (Is_Entity_Name
(Choice
) and then Is_Type
(Entity
(Choice
)))
742 if not Is_Constrained
(Etype
(Choice
)) then
747 Typlen
: constant Uint
:=
748 String_Type_Len
(Etype
(Choice
));
749 Strlen
: constant Uint
:=
750 UI_From_Int
(String_Length
(Strval
(ValS
)));
752 if Typlen
= Strlen
then
761 if String_Equal
(Strval
(ValS
), Strval
(Expr_Value_S
(Choice
)))
775 function Choices_Match
777 Choices
: List_Id
) return Match_Result
780 Result
: Match_Result
;
783 Choice
:= First
(Choices
);
784 while Present
(Choice
) loop
785 Result
:= Choice_Matches
(Expr
, Choice
);
787 if Result
/= No_Match
then
797 --------------------------
798 -- Compile_Time_Compare --
799 --------------------------
801 function Compile_Time_Compare
803 Assume_Valid
: Boolean) return Compare_Result
805 Discard
: aliased Uint
;
807 return Compile_Time_Compare
(L
, R
, Discard
'Access, Assume_Valid
);
808 end Compile_Time_Compare
;
810 function Compile_Time_Compare
813 Assume_Valid
: Boolean;
814 Rec
: Boolean := False) return Compare_Result
816 Ltyp
: Entity_Id
:= Etype
(L
);
817 Rtyp
: Entity_Id
:= Etype
(R
);
819 Discard
: aliased Uint
;
821 procedure Compare_Decompose
825 -- This procedure decomposes the node N into an expression node and a
826 -- signed offset, so that the value of N is equal to the value of R plus
827 -- the value V (which may be negative). If no such decomposition is
828 -- possible, then on return R is a copy of N, and V is set to zero.
830 function Compare_Fixup
(N
: Node_Id
) return Node_Id
;
831 -- This function deals with replacing 'Last and 'First references with
832 -- their corresponding type bounds, which we then can compare. The
833 -- argument is the original node, the result is the identity, unless we
834 -- have a 'Last/'First reference in which case the value returned is the
835 -- appropriate type bound.
837 function Is_Known_Valid_Operand
(Opnd
: Node_Id
) return Boolean;
838 -- Even if the context does not assume that values are valid, some
839 -- simple cases can be recognized.
841 function Is_Same_Value
(L
, R
: Node_Id
) return Boolean;
842 -- Returns True iff L and R represent expressions that definitely have
843 -- identical (but not necessarily compile time known) values Indeed the
844 -- caller is expected to have already dealt with the cases of compile
845 -- time known values, so these are not tested here.
847 -----------------------
848 -- Compare_Decompose --
849 -----------------------
851 procedure Compare_Decompose
857 if Nkind
(N
) = N_Op_Add
858 and then Nkind
(Right_Opnd
(N
)) = N_Integer_Literal
861 V
:= Intval
(Right_Opnd
(N
));
864 elsif Nkind
(N
) = N_Op_Subtract
865 and then Nkind
(Right_Opnd
(N
)) = N_Integer_Literal
868 V
:= UI_Negate
(Intval
(Right_Opnd
(N
)));
871 elsif Nkind
(N
) = N_Attribute_Reference
then
872 if Attribute_Name
(N
) = Name_Succ
then
873 R
:= First
(Expressions
(N
));
877 elsif Attribute_Name
(N
) = Name_Pred
then
878 R
:= First
(Expressions
(N
));
886 end Compare_Decompose
;
892 function Compare_Fixup
(N
: Node_Id
) return Node_Id
is
898 -- Fixup only required for First/Last attribute reference
900 if Nkind
(N
) = N_Attribute_Reference
901 and then Nam_In
(Attribute_Name
(N
), Name_First
, Name_Last
)
903 Xtyp
:= Etype
(Prefix
(N
));
905 -- If we have no type, then just abandon the attempt to do
906 -- a fixup, this is probably the result of some other error.
912 -- Dereference an access type
914 if Is_Access_Type
(Xtyp
) then
915 Xtyp
:= Designated_Type
(Xtyp
);
918 -- If we don't have an array type at this stage, something is
919 -- peculiar, e.g. another error, and we abandon the attempt at
922 if not Is_Array_Type
(Xtyp
) then
926 -- Ignore unconstrained array, since bounds are not meaningful
928 if not Is_Constrained
(Xtyp
) then
932 if Ekind
(Xtyp
) = E_String_Literal_Subtype
then
933 if Attribute_Name
(N
) = Name_First
then
934 return String_Literal_Low_Bound
(Xtyp
);
937 Make_Integer_Literal
(Sloc
(N
),
938 Intval
=> Intval
(String_Literal_Low_Bound
(Xtyp
)) +
939 String_Literal_Length
(Xtyp
));
943 -- Find correct index type
945 Indx
:= First_Index
(Xtyp
);
947 if Present
(Expressions
(N
)) then
948 Subs
:= UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
950 for J
in 2 .. Subs
loop
951 Indx
:= Next_Index
(Indx
);
955 Xtyp
:= Etype
(Indx
);
957 if Attribute_Name
(N
) = Name_First
then
958 return Type_Low_Bound
(Xtyp
);
960 return Type_High_Bound
(Xtyp
);
967 ----------------------------
968 -- Is_Known_Valid_Operand --
969 ----------------------------
971 function Is_Known_Valid_Operand
(Opnd
: Node_Id
) return Boolean is
973 return (Is_Entity_Name
(Opnd
)
975 (Is_Known_Valid
(Entity
(Opnd
))
976 or else Ekind
(Entity
(Opnd
)) = E_In_Parameter
978 (Ekind
(Entity
(Opnd
)) in Object_Kind
979 and then Present
(Current_Value
(Entity
(Opnd
))))))
980 or else Is_OK_Static_Expression
(Opnd
);
981 end Is_Known_Valid_Operand
;
987 function Is_Same_Value
(L
, R
: Node_Id
) return Boolean is
988 Lf
: constant Node_Id
:= Compare_Fixup
(L
);
989 Rf
: constant Node_Id
:= Compare_Fixup
(R
);
991 function Is_Same_Subscript
(L
, R
: List_Id
) return Boolean;
992 -- L, R are the Expressions values from two attribute nodes for First
993 -- or Last attributes. Either may be set to No_List if no expressions
994 -- are present (indicating subscript 1). The result is True if both
995 -- expressions represent the same subscript (note one case is where
996 -- one subscript is missing and the other is explicitly set to 1).
998 -----------------------
999 -- Is_Same_Subscript --
1000 -----------------------
1002 function Is_Same_Subscript
(L
, R
: List_Id
) return Boolean is
1008 return Expr_Value
(First
(R
)) = Uint_1
;
1013 return Expr_Value
(First
(L
)) = Uint_1
;
1015 return Expr_Value
(First
(L
)) = Expr_Value
(First
(R
));
1018 end Is_Same_Subscript
;
1020 -- Start of processing for Is_Same_Value
1023 -- Values are the same if they refer to the same entity and the
1024 -- entity is non-volatile. This does not however apply to Float
1025 -- types, since we may have two NaN values and they should never
1028 -- If the entity is a discriminant, the two expressions may be bounds
1029 -- of components of objects of the same discriminated type. The
1030 -- values of the discriminants are not static, and therefore the
1031 -- result is unknown.
1033 -- It would be better to comment individual branches of this test ???
1035 if Nkind_In
(Lf
, N_Identifier
, N_Expanded_Name
)
1036 and then Nkind_In
(Rf
, N_Identifier
, N_Expanded_Name
)
1037 and then Entity
(Lf
) = Entity
(Rf
)
1038 and then Ekind
(Entity
(Lf
)) /= E_Discriminant
1039 and then Present
(Entity
(Lf
))
1040 and then not Is_Floating_Point_Type
(Etype
(L
))
1041 and then not Is_Volatile_Reference
(L
)
1042 and then not Is_Volatile_Reference
(R
)
1046 -- Or if they are compile time known and identical
1048 elsif Compile_Time_Known_Value
(Lf
)
1050 Compile_Time_Known_Value
(Rf
)
1051 and then Expr_Value
(Lf
) = Expr_Value
(Rf
)
1055 -- False if Nkind of the two nodes is different for remaining cases
1057 elsif Nkind
(Lf
) /= Nkind
(Rf
) then
1060 -- True if both 'First or 'Last values applying to the same entity
1061 -- (first and last don't change even if value does). Note that we
1062 -- need this even with the calls to Compare_Fixup, to handle the
1063 -- case of unconstrained array attributes where Compare_Fixup
1064 -- cannot find useful bounds.
1066 elsif Nkind
(Lf
) = N_Attribute_Reference
1067 and then Attribute_Name
(Lf
) = Attribute_Name
(Rf
)
1068 and then Nam_In
(Attribute_Name
(Lf
), Name_First
, Name_Last
)
1069 and then Nkind_In
(Prefix
(Lf
), N_Identifier
, N_Expanded_Name
)
1070 and then Nkind_In
(Prefix
(Rf
), N_Identifier
, N_Expanded_Name
)
1071 and then Entity
(Prefix
(Lf
)) = Entity
(Prefix
(Rf
))
1072 and then Is_Same_Subscript
(Expressions
(Lf
), Expressions
(Rf
))
1076 -- True if the same selected component from the same record
1078 elsif Nkind
(Lf
) = N_Selected_Component
1079 and then Selector_Name
(Lf
) = Selector_Name
(Rf
)
1080 and then Is_Same_Value
(Prefix
(Lf
), Prefix
(Rf
))
1084 -- True if the same unary operator applied to the same operand
1086 elsif Nkind
(Lf
) in N_Unary_Op
1087 and then Is_Same_Value
(Right_Opnd
(Lf
), Right_Opnd
(Rf
))
1091 -- True if the same binary operator applied to the same operands
1093 elsif Nkind
(Lf
) in N_Binary_Op
1094 and then Is_Same_Value
(Left_Opnd
(Lf
), Left_Opnd
(Rf
))
1095 and then Is_Same_Value
(Right_Opnd
(Lf
), Right_Opnd
(Rf
))
1099 -- All other cases, we can't tell, so return False
1106 -- Start of processing for Compile_Time_Compare
1109 Diff
.all := No_Uint
;
1111 -- In preanalysis mode, always return Unknown unless the expression
1112 -- is static. It is too early to be thinking we know the result of a
1113 -- comparison, save that judgment for the full analysis. This is
1114 -- particularly important in the case of pre and postconditions, which
1115 -- otherwise can be prematurely collapsed into having True or False
1116 -- conditions when this is inappropriate.
1118 if not (Full_Analysis
1119 or else (Is_OK_Static_Expression
(L
)
1121 Is_OK_Static_Expression
(R
)))
1126 -- If either operand could raise constraint error, then we cannot
1127 -- know the result at compile time (since CE may be raised).
1129 if not (Cannot_Raise_Constraint_Error
(L
)
1131 Cannot_Raise_Constraint_Error
(R
))
1136 -- Identical operands are most certainly equal
1142 -- If expressions have no types, then do not attempt to determine if
1143 -- they are the same, since something funny is going on. One case in
1144 -- which this happens is during generic template analysis, when bounds
1145 -- are not fully analyzed.
1147 if No
(Ltyp
) or else No
(Rtyp
) then
1151 -- These get reset to the base type for the case of entities where
1152 -- Is_Known_Valid is not set. This takes care of handling possible
1153 -- invalid representations using the value of the base type, in
1154 -- accordance with RM 13.9.1(10).
1156 Ltyp
:= Underlying_Type
(Ltyp
);
1157 Rtyp
:= Underlying_Type
(Rtyp
);
1159 -- Same rationale as above, but for Underlying_Type instead of Etype
1161 if No
(Ltyp
) or else No
(Rtyp
) then
1165 -- We do not attempt comparisons for packed arrays represented as
1166 -- modular types, where the semantics of comparison is quite different.
1168 if Is_Packed_Array_Impl_Type
(Ltyp
)
1169 and then Is_Modular_Integer_Type
(Ltyp
)
1173 -- For access types, the only time we know the result at compile time
1174 -- (apart from identical operands, which we handled already) is if we
1175 -- know one operand is null and the other is not, or both operands are
1178 elsif Is_Access_Type
(Ltyp
) then
1179 if Known_Null
(L
) then
1180 if Known_Null
(R
) then
1182 elsif Known_Non_Null
(R
) then
1188 elsif Known_Non_Null
(L
) and then Known_Null
(R
) then
1195 -- Case where comparison involves two compile time known values
1197 elsif Compile_Time_Known_Value
(L
)
1199 Compile_Time_Known_Value
(R
)
1201 -- For the floating-point case, we have to be a little careful, since
1202 -- at compile time we are dealing with universal exact values, but at
1203 -- runtime, these will be in non-exact target form. That's why the
1204 -- returned results are LE and GE below instead of LT and GT.
1206 if Is_Floating_Point_Type
(Ltyp
)
1208 Is_Floating_Point_Type
(Rtyp
)
1211 Lo
: constant Ureal
:= Expr_Value_R
(L
);
1212 Hi
: constant Ureal
:= Expr_Value_R
(R
);
1223 -- For string types, we have two string literals and we proceed to
1224 -- compare them using the Ada style dictionary string comparison.
1226 elsif not Is_Scalar_Type
(Ltyp
) then
1228 Lstring
: constant String_Id
:= Strval
(Expr_Value_S
(L
));
1229 Rstring
: constant String_Id
:= Strval
(Expr_Value_S
(R
));
1230 Llen
: constant Nat
:= String_Length
(Lstring
);
1231 Rlen
: constant Nat
:= String_Length
(Rstring
);
1234 for J
in 1 .. Nat
'Min (Llen
, Rlen
) loop
1236 LC
: constant Char_Code
:= Get_String_Char
(Lstring
, J
);
1237 RC
: constant Char_Code
:= Get_String_Char
(Rstring
, J
);
1249 elsif Llen
> Rlen
then
1256 -- For remaining scalar cases we know exactly (note that this does
1257 -- include the fixed-point case, where we know the run time integer
1262 Lo
: constant Uint
:= Expr_Value
(L
);
1263 Hi
: constant Uint
:= Expr_Value
(R
);
1266 Diff
.all := Hi
- Lo
;
1271 Diff
.all := Lo
- Hi
;
1277 -- Cases where at least one operand is not known at compile time
1280 -- Remaining checks apply only for discrete types
1282 if not Is_Discrete_Type
(Ltyp
)
1284 not Is_Discrete_Type
(Rtyp
)
1289 -- Defend against generic types, or actually any expressions that
1290 -- contain a reference to a generic type from within a generic
1291 -- template. We don't want to do any range analysis of such
1292 -- expressions for two reasons. First, the bounds of a generic type
1293 -- itself are junk and cannot be used for any kind of analysis.
1294 -- Second, we may have a case where the range at run time is indeed
1295 -- known, but we don't want to do compile time analysis in the
1296 -- template based on that range since in an instance the value may be
1297 -- static, and able to be elaborated without reference to the bounds
1298 -- of types involved. As an example, consider:
1300 -- (F'Pos (F'Last) + 1) > Integer'Last
1302 -- The expression on the left side of > is Universal_Integer and thus
1303 -- acquires the type Integer for evaluation at run time, and at run
1304 -- time it is true that this condition is always False, but within
1305 -- an instance F may be a type with a static range greater than the
1306 -- range of Integer, and the expression statically evaluates to True.
1308 if References_Generic_Formal_Type
(L
)
1310 References_Generic_Formal_Type
(R
)
1315 -- Replace types by base types for the case of values which are not
1316 -- known to have valid representations. This takes care of properly
1317 -- dealing with invalid representations.
1319 if not Assume_Valid
then
1320 if not (Is_Entity_Name
(L
)
1321 and then (Is_Known_Valid
(Entity
(L
))
1322 or else Assume_No_Invalid_Values
))
1324 Ltyp
:= Underlying_Type
(Base_Type
(Ltyp
));
1327 if not (Is_Entity_Name
(R
)
1328 and then (Is_Known_Valid
(Entity
(R
))
1329 or else Assume_No_Invalid_Values
))
1331 Rtyp
:= Underlying_Type
(Base_Type
(Rtyp
));
1335 -- First attempt is to decompose the expressions to extract a
1336 -- constant offset resulting from the use of any of the forms:
1343 -- Then we see if the two expressions are the same value, and if so
1344 -- the result is obtained by comparing the offsets.
1346 -- Note: the reason we do this test first is that it returns only
1347 -- decisive results (with diff set), where other tests, like the
1348 -- range test, may not be as so decisive. Consider for example
1349 -- J .. J + 1. This code can conclude LT with a difference of 1,
1350 -- even if the range of J is not known.
1359 Compare_Decompose
(L
, Lnode
, Loffs
);
1360 Compare_Decompose
(R
, Rnode
, Roffs
);
1362 if Is_Same_Value
(Lnode
, Rnode
) then
1363 if Loffs
= Roffs
then
1367 -- When the offsets are not equal, we can go farther only if
1368 -- the types are not modular (e.g. X < X + 1 is False if X is
1369 -- the largest number).
1371 if not Is_Modular_Integer_Type
(Ltyp
)
1372 and then not Is_Modular_Integer_Type
(Rtyp
)
1374 if Loffs
< Roffs
then
1375 Diff
.all := Roffs
- Loffs
;
1378 Diff
.all := Loffs
- Roffs
;
1385 -- Next, try range analysis and see if operand ranges are disjoint
1393 -- True if each range is a single point
1396 Determine_Range
(L
, LOK
, LLo
, LHi
, Assume_Valid
);
1397 Determine_Range
(R
, ROK
, RLo
, RHi
, Assume_Valid
);
1400 Single
:= (LLo
= LHi
) and then (RLo
= RHi
);
1403 if Single
and Assume_Valid
then
1404 Diff
.all := RLo
- LLo
;
1409 elsif RHi
< LLo
then
1410 if Single
and Assume_Valid
then
1411 Diff
.all := LLo
- RLo
;
1416 elsif Single
and then LLo
= RLo
then
1418 -- If the range includes a single literal and we can assume
1419 -- validity then the result is known even if an operand is
1422 if Assume_Valid
then
1428 elsif LHi
= RLo
then
1431 elsif RHi
= LLo
then
1434 elsif not Is_Known_Valid_Operand
(L
)
1435 and then not Assume_Valid
1437 if Is_Same_Value
(L
, R
) then
1444 -- If the range of either operand cannot be determined, nothing
1445 -- further can be inferred.
1452 -- Here is where we check for comparisons against maximum bounds of
1453 -- types, where we know that no value can be outside the bounds of
1454 -- the subtype. Note that this routine is allowed to assume that all
1455 -- expressions are within their subtype bounds. Callers wishing to
1456 -- deal with possibly invalid values must in any case take special
1457 -- steps (e.g. conversions to larger types) to avoid this kind of
1458 -- optimization, which is always considered to be valid. We do not
1459 -- attempt this optimization with generic types, since the type
1460 -- bounds may not be meaningful in this case.
1462 -- We are in danger of an infinite recursion here. It does not seem
1463 -- useful to go more than one level deep, so the parameter Rec is
1464 -- used to protect ourselves against this infinite recursion.
1468 -- See if we can get a decisive check against one operand and a
1469 -- bound of the other operand (four possible tests here). Note
1470 -- that we avoid testing junk bounds of a generic type.
1472 if not Is_Generic_Type
(Rtyp
) then
1473 case Compile_Time_Compare
(L
, Type_Low_Bound
(Rtyp
),
1475 Assume_Valid
, Rec
=> True)
1477 when LT
=> return LT
;
1478 when LE
=> return LE
;
1479 when EQ
=> return LE
;
1480 when others => null;
1483 case Compile_Time_Compare
(L
, Type_High_Bound
(Rtyp
),
1485 Assume_Valid
, Rec
=> True)
1487 when GT
=> return GT
;
1488 when GE
=> return GE
;
1489 when EQ
=> return GE
;
1490 when others => null;
1494 if not Is_Generic_Type
(Ltyp
) then
1495 case Compile_Time_Compare
(Type_Low_Bound
(Ltyp
), R
,
1497 Assume_Valid
, Rec
=> True)
1499 when GT
=> return GT
;
1500 when GE
=> return GE
;
1501 when EQ
=> return GE
;
1502 when others => null;
1505 case Compile_Time_Compare
(Type_High_Bound
(Ltyp
), R
,
1507 Assume_Valid
, Rec
=> True)
1509 when LT
=> return LT
;
1510 when LE
=> return LE
;
1511 when EQ
=> return LE
;
1512 when others => null;
1517 -- Next attempt is to see if we have an entity compared with a
1518 -- compile time known value, where there is a current value
1519 -- conditional for the entity which can tell us the result.
1523 -- Entity variable (left operand)
1526 -- Value (right operand)
1529 -- If False, we have reversed the operands
1532 -- Comparison operator kind from Get_Current_Value_Condition call
1535 -- Value from Get_Current_Value_Condition call
1540 Result
: Compare_Result
;
1541 -- Known result before inversion
1544 if Is_Entity_Name
(L
)
1545 and then Compile_Time_Known_Value
(R
)
1548 Val
:= Expr_Value
(R
);
1551 elsif Is_Entity_Name
(R
)
1552 and then Compile_Time_Known_Value
(L
)
1555 Val
:= Expr_Value
(L
);
1558 -- That was the last chance at finding a compile time result
1564 Get_Current_Value_Condition
(Var
, Op
, Opn
);
1566 -- That was the last chance, so if we got nothing return
1572 Opv
:= Expr_Value
(Opn
);
1574 -- We got a comparison, so we might have something interesting
1576 -- Convert LE to LT and GE to GT, just so we have fewer cases
1578 if Op
= N_Op_Le
then
1582 elsif Op
= N_Op_Ge
then
1587 -- Deal with equality case
1589 if Op
= N_Op_Eq
then
1592 elsif Opv
< Val
then
1598 -- Deal with inequality case
1600 elsif Op
= N_Op_Ne
then
1607 -- Deal with greater than case
1609 elsif Op
= N_Op_Gt
then
1612 elsif Opv
= Val
- 1 then
1618 -- Deal with less than case
1620 else pragma Assert
(Op
= N_Op_Lt
);
1623 elsif Opv
= Val
+ 1 then
1630 -- Deal with inverting result
1634 when GT
=> return LT
;
1635 when GE
=> return LE
;
1636 when LT
=> return GT
;
1637 when LE
=> return GE
;
1638 when others => return Result
;
1645 end Compile_Time_Compare
;
1647 -------------------------------
1648 -- Compile_Time_Known_Bounds --
1649 -------------------------------
1651 function Compile_Time_Known_Bounds
(T
: Entity_Id
) return Boolean is
1656 if T
= Any_Composite
or else not Is_Array_Type
(T
) then
1660 Indx
:= First_Index
(T
);
1661 while Present
(Indx
) loop
1662 Typ
:= Underlying_Type
(Etype
(Indx
));
1664 -- Never look at junk bounds of a generic type
1666 if Is_Generic_Type
(Typ
) then
1670 -- Otherwise check bounds for compile time known
1672 if not Compile_Time_Known_Value
(Type_Low_Bound
(Typ
)) then
1674 elsif not Compile_Time_Known_Value
(Type_High_Bound
(Typ
)) then
1682 end Compile_Time_Known_Bounds
;
1684 ------------------------------
1685 -- Compile_Time_Known_Value --
1686 ------------------------------
1688 function Compile_Time_Known_Value
(Op
: Node_Id
) return Boolean is
1689 K
: constant Node_Kind
:= Nkind
(Op
);
1690 CV_Ent
: CV_Entry
renames CV_Cache
(Nat
(Op
) mod CV_Cache_Size
);
1693 -- Never known at compile time if bad type or raises constraint error
1694 -- or empty (latter case occurs only as a result of a previous error).
1697 Check_Error_Detected
;
1701 or else Etype
(Op
) = Any_Type
1702 or else Raises_Constraint_Error
(Op
)
1707 -- If we have an entity name, then see if it is the name of a constant
1708 -- and if so, test the corresponding constant value, or the name of
1709 -- an enumeration literal, which is always a constant.
1711 if Present
(Etype
(Op
)) and then Is_Entity_Name
(Op
) then
1713 E
: constant Entity_Id
:= Entity
(Op
);
1717 -- Never known at compile time if it is a packed array value.
1718 -- We might want to try to evaluate these at compile time one
1719 -- day, but we do not make that attempt now.
1721 if Is_Packed_Array_Impl_Type
(Etype
(Op
)) then
1725 if Ekind
(E
) = E_Enumeration_Literal
then
1728 elsif Ekind
(E
) = E_Constant
then
1729 V
:= Constant_Value
(E
);
1730 return Present
(V
) and then Compile_Time_Known_Value
(V
);
1734 -- We have a value, see if it is compile time known
1737 -- Integer literals are worth storing in the cache
1739 if K
= N_Integer_Literal
then
1741 CV_Ent
.V
:= Intval
(Op
);
1744 -- Other literals and NULL are known at compile time
1747 Nkind_In
(K
, N_Character_Literal
,
1756 -- If we fall through, not known at compile time
1760 -- If we get an exception while trying to do this test, then some error
1761 -- has occurred, and we simply say that the value is not known after all
1766 end Compile_Time_Known_Value
;
1768 --------------------------------------
1769 -- Compile_Time_Known_Value_Or_Aggr --
1770 --------------------------------------
1772 function Compile_Time_Known_Value_Or_Aggr
(Op
: Node_Id
) return Boolean is
1774 -- If we have an entity name, then see if it is the name of a constant
1775 -- and if so, test the corresponding constant value, or the name of
1776 -- an enumeration literal, which is always a constant.
1778 if Is_Entity_Name
(Op
) then
1780 E
: constant Entity_Id
:= Entity
(Op
);
1784 if Ekind
(E
) = E_Enumeration_Literal
then
1787 elsif Ekind
(E
) /= E_Constant
then
1791 V
:= Constant_Value
(E
);
1793 and then Compile_Time_Known_Value_Or_Aggr
(V
);
1797 -- We have a value, see if it is compile time known
1800 if Compile_Time_Known_Value
(Op
) then
1803 elsif Nkind
(Op
) = N_Aggregate
then
1805 if Present
(Expressions
(Op
)) then
1809 Expr
:= First
(Expressions
(Op
));
1810 while Present
(Expr
) loop
1811 if not Compile_Time_Known_Value_Or_Aggr
(Expr
) then
1820 if Present
(Component_Associations
(Op
)) then
1825 Cass
:= First
(Component_Associations
(Op
));
1826 while Present
(Cass
) loop
1828 Compile_Time_Known_Value_Or_Aggr
(Expression
(Cass
))
1840 elsif Nkind
(Op
) = N_Qualified_Expression
then
1841 return Compile_Time_Known_Value_Or_Aggr
(Expression
(Op
));
1843 -- All other types of values are not known at compile time
1850 end Compile_Time_Known_Value_Or_Aggr
;
1852 ---------------------------------------
1853 -- CRT_Safe_Compile_Time_Known_Value --
1854 ---------------------------------------
1856 function CRT_Safe_Compile_Time_Known_Value
(Op
: Node_Id
) return Boolean is
1858 if (Configurable_Run_Time_Mode
or No_Run_Time_Mode
)
1859 and then not Is_OK_Static_Expression
(Op
)
1863 return Compile_Time_Known_Value
(Op
);
1865 end CRT_Safe_Compile_Time_Known_Value
;
1871 -- This is only called for actuals of functions that are not predefined
1872 -- operators (which have already been rewritten as operators at this
1873 -- stage), so the call can never be folded, and all that needs doing for
1874 -- the actual is to do the check for a non-static context.
1876 procedure Eval_Actual
(N
: Node_Id
) is
1878 Check_Non_Static_Context
(N
);
1881 --------------------
1882 -- Eval_Allocator --
1883 --------------------
1885 -- Allocators are never static, so all we have to do is to do the
1886 -- check for a non-static context if an expression is present.
1888 procedure Eval_Allocator
(N
: Node_Id
) is
1889 Expr
: constant Node_Id
:= Expression
(N
);
1891 if Nkind
(Expr
) = N_Qualified_Expression
then
1892 Check_Non_Static_Context
(Expression
(Expr
));
1896 ------------------------
1897 -- Eval_Arithmetic_Op --
1898 ------------------------
1900 -- Arithmetic operations are static functions, so the result is static
1901 -- if both operands are static (RM 4.9(7), 4.9(20)).
1903 procedure Eval_Arithmetic_Op
(N
: Node_Id
) is
1904 Left
: constant Node_Id
:= Left_Opnd
(N
);
1905 Right
: constant Node_Id
:= Right_Opnd
(N
);
1906 Ltype
: constant Entity_Id
:= Etype
(Left
);
1907 Rtype
: constant Entity_Id
:= Etype
(Right
);
1908 Otype
: Entity_Id
:= Empty
;
1913 -- If not foldable we are done
1915 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
1921 -- Otherwise attempt to fold
1923 if Is_Universal_Numeric_Type
(Etype
(Left
))
1925 Is_Universal_Numeric_Type
(Etype
(Right
))
1927 Otype
:= Find_Universal_Operator_Type
(N
);
1930 -- Fold for cases where both operands are of integer type
1932 if Is_Integer_Type
(Ltype
) and then Is_Integer_Type
(Rtype
) then
1934 Left_Int
: constant Uint
:= Expr_Value
(Left
);
1935 Right_Int
: constant Uint
:= Expr_Value
(Right
);
1941 Result
:= Left_Int
+ Right_Int
;
1943 when N_Op_Subtract
=>
1944 Result
:= Left_Int
- Right_Int
;
1946 when N_Op_Multiply
=>
1949 (Num_Bits
(Left_Int
) + Num_Bits
(Right_Int
)))
1951 Result
:= Left_Int
* Right_Int
;
1958 -- The exception Constraint_Error is raised by integer
1959 -- division, rem and mod if the right operand is zero.
1961 if Right_Int
= 0 then
1963 -- When SPARK_Mode is On, force a warning instead of
1964 -- an error in that case, as this likely corresponds
1965 -- to deactivated code.
1967 Apply_Compile_Time_Constraint_Error
1968 (N
, "division by zero", CE_Divide_By_Zero
,
1969 Warn
=> not Stat
or SPARK_Mode
= On
);
1970 Set_Raises_Constraint_Error
(N
);
1973 -- Otherwise we can do the division
1976 Result
:= Left_Int
/ Right_Int
;
1981 -- The exception Constraint_Error is raised by integer
1982 -- division, rem and mod if the right operand is zero.
1984 if Right_Int
= 0 then
1986 -- When SPARK_Mode is On, force a warning instead of
1987 -- an error in that case, as this likely corresponds
1988 -- to deactivated code.
1990 Apply_Compile_Time_Constraint_Error
1991 (N
, "mod with zero divisor", CE_Divide_By_Zero
,
1992 Warn
=> not Stat
or SPARK_Mode
= On
);
1996 Result
:= Left_Int
mod Right_Int
;
2001 -- The exception Constraint_Error is raised by integer
2002 -- division, rem and mod if the right operand is zero.
2004 if Right_Int
= 0 then
2006 -- When SPARK_Mode is On, force a warning instead of
2007 -- an error in that case, as this likely corresponds
2008 -- to deactivated code.
2010 Apply_Compile_Time_Constraint_Error
2011 (N
, "rem with zero divisor", CE_Divide_By_Zero
,
2012 Warn
=> not Stat
or SPARK_Mode
= On
);
2016 Result
:= Left_Int
rem Right_Int
;
2020 raise Program_Error
;
2023 -- Adjust the result by the modulus if the type is a modular type
2025 if Is_Modular_Integer_Type
(Ltype
) then
2026 Result
:= Result
mod Modulus
(Ltype
);
2028 -- For a signed integer type, check non-static overflow
2030 elsif (not Stat
) and then Is_Signed_Integer_Type
(Ltype
) then
2032 BT
: constant Entity_Id
:= Base_Type
(Ltype
);
2033 Lo
: constant Uint
:= Expr_Value
(Type_Low_Bound
(BT
));
2034 Hi
: constant Uint
:= Expr_Value
(Type_High_Bound
(BT
));
2036 if Result
< Lo
or else Result
> Hi
then
2037 Apply_Compile_Time_Constraint_Error
2038 (N
, "value not in range of }??",
2039 CE_Overflow_Check_Failed
,
2046 -- If we get here we can fold the result
2048 Fold_Uint
(N
, Result
, Stat
);
2051 -- Cases where at least one operand is a real. We handle the cases of
2052 -- both reals, or mixed/real integer cases (the latter happen only for
2053 -- divide and multiply, and the result is always real).
2055 elsif Is_Real_Type
(Ltype
) or else Is_Real_Type
(Rtype
) then
2062 if Is_Real_Type
(Ltype
) then
2063 Left_Real
:= Expr_Value_R
(Left
);
2065 Left_Real
:= UR_From_Uint
(Expr_Value
(Left
));
2068 if Is_Real_Type
(Rtype
) then
2069 Right_Real
:= Expr_Value_R
(Right
);
2071 Right_Real
:= UR_From_Uint
(Expr_Value
(Right
));
2074 if Nkind
(N
) = N_Op_Add
then
2075 Result
:= Left_Real
+ Right_Real
;
2077 elsif Nkind
(N
) = N_Op_Subtract
then
2078 Result
:= Left_Real
- Right_Real
;
2080 elsif Nkind
(N
) = N_Op_Multiply
then
2081 Result
:= Left_Real
* Right_Real
;
2083 else pragma Assert
(Nkind
(N
) = N_Op_Divide
);
2084 if UR_Is_Zero
(Right_Real
) then
2085 Apply_Compile_Time_Constraint_Error
2086 (N
, "division by zero", CE_Divide_By_Zero
);
2090 Result
:= Left_Real
/ Right_Real
;
2093 Fold_Ureal
(N
, Result
, Stat
);
2097 -- If the operator was resolved to a specific type, make sure that type
2098 -- is frozen even if the expression is folded into a literal (which has
2099 -- a universal type).
2101 if Present
(Otype
) then
2102 Freeze_Before
(N
, Otype
);
2104 end Eval_Arithmetic_Op
;
2106 ----------------------------
2107 -- Eval_Character_Literal --
2108 ----------------------------
2110 -- Nothing to be done
2112 procedure Eval_Character_Literal
(N
: Node_Id
) is
2113 pragma Warnings
(Off
, N
);
2116 end Eval_Character_Literal
;
2122 -- Static function calls are either calls to predefined operators
2123 -- with static arguments, or calls to functions that rename a literal.
2124 -- Only the latter case is handled here, predefined operators are
2125 -- constant-folded elsewhere.
2127 -- If the function is itself inherited (see 7423-001) the literal of
2128 -- the parent type must be explicitly converted to the return type
2131 procedure Eval_Call
(N
: Node_Id
) is
2132 Loc
: constant Source_Ptr
:= Sloc
(N
);
2133 Typ
: constant Entity_Id
:= Etype
(N
);
2137 if Nkind
(N
) = N_Function_Call
2138 and then No
(Parameter_Associations
(N
))
2139 and then Is_Entity_Name
(Name
(N
))
2140 and then Present
(Alias
(Entity
(Name
(N
))))
2141 and then Is_Enumeration_Type
(Base_Type
(Typ
))
2143 Lit
:= Ultimate_Alias
(Entity
(Name
(N
)));
2145 if Ekind
(Lit
) = E_Enumeration_Literal
then
2146 if Base_Type
(Etype
(Lit
)) /= Base_Type
(Typ
) then
2148 (N
, Convert_To
(Typ
, New_Occurrence_Of
(Lit
, Loc
)));
2150 Rewrite
(N
, New_Occurrence_Of
(Lit
, Loc
));
2158 --------------------------
2159 -- Eval_Case_Expression --
2160 --------------------------
2162 -- A conditional expression is static if all its conditions and dependent
2163 -- expressions are static. Note that we do not care if the dependent
2164 -- expressions raise CE, except for the one that will be selected.
2166 procedure Eval_Case_Expression
(N
: Node_Id
) is
2171 Set_Is_Static_Expression
(N
, False);
2173 if Error_Posted
(Expression
(N
))
2174 or else not Is_Static_Expression
(Expression
(N
))
2176 Check_Non_Static_Context
(Expression
(N
));
2180 -- First loop, make sure all the alternatives are static expressions
2181 -- none of which raise Constraint_Error. We make the constraint error
2182 -- check because part of the legality condition for a correct static
2183 -- case expression is that the cases are covered, like any other case
2184 -- expression. And we can't do that if any of the conditions raise an
2185 -- exception, so we don't even try to evaluate if that is the case.
2187 Alt
:= First
(Alternatives
(N
));
2188 while Present
(Alt
) loop
2190 -- The expression must be static, but we don't care at this stage
2191 -- if it raises Constraint_Error (the alternative might not match,
2192 -- in which case the expression is statically unevaluated anyway).
2194 if not Is_Static_Expression
(Expression
(Alt
)) then
2195 Check_Non_Static_Context
(Expression
(Alt
));
2199 -- The choices of a case always have to be static, and cannot raise
2200 -- an exception. If this condition is not met, then the expression
2201 -- is plain illegal, so just abandon evaluation attempts. No need
2202 -- to check non-static context when we have something illegal anyway.
2204 if not Is_OK_Static_Choice_List
(Discrete_Choices
(Alt
)) then
2211 -- OK, if the above loop gets through it means that all choices are OK
2212 -- static (don't raise exceptions), so the whole case is static, and we
2213 -- can find the matching alternative.
2215 Set_Is_Static_Expression
(N
);
2217 -- Now to deal with propagating a possible constraint error
2219 -- If the selecting expression raises CE, propagate and we are done
2221 if Raises_Constraint_Error
(Expression
(N
)) then
2222 Set_Raises_Constraint_Error
(N
);
2224 -- Otherwise we need to check the alternatives to find the matching
2225 -- one. CE's in other than the matching one are not relevant. But we
2226 -- do need to check the matching one. Unlike the first loop, we do not
2227 -- have to go all the way through, when we find the matching one, quit.
2230 Alt
:= First
(Alternatives
(N
));
2233 -- We must find a match among the alternatives. If not, this must
2234 -- be due to other errors, so just ignore, leaving as non-static.
2237 Set_Is_Static_Expression
(N
, False);
2241 -- Otherwise loop through choices of this alternative
2243 Choice
:= First
(Discrete_Choices
(Alt
));
2244 while Present
(Choice
) loop
2246 -- If we find a matching choice, then the Expression of this
2247 -- alternative replaces N (Raises_Constraint_Error flag is
2248 -- included, so we don't have to special case that).
2250 if Choice_Matches
(Expression
(N
), Choice
) = Match
then
2251 Rewrite
(N
, Relocate_Node
(Expression
(Alt
)));
2261 end Eval_Case_Expression
;
2263 ------------------------
2264 -- Eval_Concatenation --
2265 ------------------------
2267 -- Concatenation is a static function, so the result is static if both
2268 -- operands are static (RM 4.9(7), 4.9(21)).
2270 procedure Eval_Concatenation
(N
: Node_Id
) is
2271 Left
: constant Node_Id
:= Left_Opnd
(N
);
2272 Right
: constant Node_Id
:= Right_Opnd
(N
);
2273 C_Typ
: constant Entity_Id
:= Root_Type
(Component_Type
(Etype
(N
)));
2278 -- Concatenation is never static in Ada 83, so if Ada 83 check operand
2279 -- non-static context.
2281 if Ada_Version
= Ada_83
2282 and then Comes_From_Source
(N
)
2284 Check_Non_Static_Context
(Left
);
2285 Check_Non_Static_Context
(Right
);
2289 -- If not foldable we are done. In principle concatenation that yields
2290 -- any string type is static (i.e. an array type of character types).
2291 -- However, character types can include enumeration literals, and
2292 -- concatenation in that case cannot be described by a literal, so we
2293 -- only consider the operation static if the result is an array of
2294 -- (a descendant of) a predefined character type.
2296 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
2298 if not (Is_Standard_Character_Type
(C_Typ
) and then Fold
) then
2299 Set_Is_Static_Expression
(N
, False);
2303 -- Compile time string concatenation
2305 -- ??? Note that operands that are aggregates can be marked as static,
2306 -- so we should attempt at a later stage to fold concatenations with
2310 Left_Str
: constant Node_Id
:= Get_String_Val
(Left
);
2312 Right_Str
: constant Node_Id
:= Get_String_Val
(Right
);
2313 Folded_Val
: String_Id
:= No_String
;
2316 -- Establish new string literal, and store left operand. We make
2317 -- sure to use the special Start_String that takes an operand if
2318 -- the left operand is a string literal. Since this is optimized
2319 -- in the case where that is the most recently created string
2320 -- literal, we ensure efficient time/space behavior for the
2321 -- case of a concatenation of a series of string literals.
2323 if Nkind
(Left_Str
) = N_String_Literal
then
2324 Left_Len
:= String_Length
(Strval
(Left_Str
));
2326 -- If the left operand is the empty string, and the right operand
2327 -- is a string literal (the case of "" & "..."), the result is the
2328 -- value of the right operand. This optimization is important when
2329 -- Is_Folded_In_Parser, to avoid copying an enormous right
2332 if Left_Len
= 0 and then Nkind
(Right_Str
) = N_String_Literal
then
2333 Folded_Val
:= Strval
(Right_Str
);
2335 Start_String
(Strval
(Left_Str
));
2340 Store_String_Char
(UI_To_CC
(Char_Literal_Value
(Left_Str
)));
2344 -- Now append the characters of the right operand, unless we
2345 -- optimized the "" & "..." case above.
2347 if Nkind
(Right_Str
) = N_String_Literal
then
2348 if Left_Len
/= 0 then
2349 Store_String_Chars
(Strval
(Right_Str
));
2350 Folded_Val
:= End_String
;
2353 Store_String_Char
(UI_To_CC
(Char_Literal_Value
(Right_Str
)));
2354 Folded_Val
:= End_String
;
2357 Set_Is_Static_Expression
(N
, Stat
);
2359 -- If left operand is the empty string, the result is the
2360 -- right operand, including its bounds if anomalous.
2363 and then Is_Array_Type
(Etype
(Right
))
2364 and then Etype
(Right
) /= Any_String
2366 Set_Etype
(N
, Etype
(Right
));
2369 Fold_Str
(N
, Folded_Val
, Static
=> Stat
);
2371 end Eval_Concatenation
;
2373 ----------------------
2374 -- Eval_Entity_Name --
2375 ----------------------
2377 -- This procedure is used for identifiers and expanded names other than
2378 -- named numbers (see Eval_Named_Integer, Eval_Named_Real. These are
2379 -- static if they denote a static constant (RM 4.9(6)) or if the name
2380 -- denotes an enumeration literal (RM 4.9(22)).
2382 procedure Eval_Entity_Name
(N
: Node_Id
) is
2383 Def_Id
: constant Entity_Id
:= Entity
(N
);
2387 -- Enumeration literals are always considered to be constants
2388 -- and cannot raise constraint error (RM 4.9(22)).
2390 if Ekind
(Def_Id
) = E_Enumeration_Literal
then
2391 Set_Is_Static_Expression
(N
);
2394 -- A name is static if it denotes a static constant (RM 4.9(5)), and
2395 -- we also copy Raise_Constraint_Error. Notice that even if non-static,
2396 -- it does not violate 10.2.1(8) here, since this is not a variable.
2398 elsif Ekind
(Def_Id
) = E_Constant
then
2400 -- Deferred constants must always be treated as nonstatic outside the
2401 -- scope of their full view.
2403 if Present
(Full_View
(Def_Id
))
2404 and then not In_Open_Scopes
(Scope
(Def_Id
))
2408 Val
:= Constant_Value
(Def_Id
);
2411 if Present
(Val
) then
2412 Set_Is_Static_Expression
2413 (N
, Is_Static_Expression
(Val
)
2414 and then Is_Static_Subtype
(Etype
(Def_Id
)));
2415 Set_Raises_Constraint_Error
(N
, Raises_Constraint_Error
(Val
));
2417 if not Is_Static_Expression
(N
)
2418 and then not Is_Generic_Type
(Etype
(N
))
2420 Validate_Static_Object_Name
(N
);
2423 -- Mark constant condition in SCOs
2426 and then Comes_From_Source
(N
)
2427 and then Is_Boolean_Type
(Etype
(Def_Id
))
2428 and then Compile_Time_Known_Value
(N
)
2430 Set_SCO_Condition
(N
, Expr_Value_E
(N
) = Standard_True
);
2437 -- Fall through if the name is not static
2439 Validate_Static_Object_Name
(N
);
2440 end Eval_Entity_Name
;
2442 ------------------------
2443 -- Eval_If_Expression --
2444 ------------------------
2446 -- We can fold to a static expression if the condition and both dependent
2447 -- expressions are static. Otherwise, the only required processing is to do
2448 -- the check for non-static context for the then and else expressions.
2450 procedure Eval_If_Expression
(N
: Node_Id
) is
2451 Condition
: constant Node_Id
:= First
(Expressions
(N
));
2452 Then_Expr
: constant Node_Id
:= Next
(Condition
);
2453 Else_Expr
: constant Node_Id
:= Next
(Then_Expr
);
2455 Non_Result
: Node_Id
;
2457 Rstat
: constant Boolean :=
2458 Is_Static_Expression
(Condition
)
2460 Is_Static_Expression
(Then_Expr
)
2462 Is_Static_Expression
(Else_Expr
);
2463 -- True if result is static
2466 -- If result not static, nothing to do, otherwise set static result
2471 Set_Is_Static_Expression
(N
);
2474 -- If any operand is Any_Type, just propagate to result and do not try
2475 -- to fold, this prevents cascaded errors.
2477 if Etype
(Condition
) = Any_Type
or else
2478 Etype
(Then_Expr
) = Any_Type
or else
2479 Etype
(Else_Expr
) = Any_Type
2481 Set_Etype
(N
, Any_Type
);
2482 Set_Is_Static_Expression
(N
, False);
2486 -- If condition raises constraint error then we have already signaled
2487 -- an error, and we just propagate to the result and do not fold.
2489 if Raises_Constraint_Error
(Condition
) then
2490 Set_Raises_Constraint_Error
(N
);
2494 -- Static case where we can fold. Note that we don't try to fold cases
2495 -- where the condition is known at compile time, but the result is
2496 -- non-static. This avoids possible cases of infinite recursion where
2497 -- the expander puts in a redundant test and we remove it. Instead we
2498 -- deal with these cases in the expander.
2500 -- Select result operand
2502 if Is_True
(Expr_Value
(Condition
)) then
2503 Result
:= Then_Expr
;
2504 Non_Result
:= Else_Expr
;
2506 Result
:= Else_Expr
;
2507 Non_Result
:= Then_Expr
;
2510 -- Note that it does not matter if the non-result operand raises a
2511 -- Constraint_Error, but if the result raises constraint error then we
2512 -- replace the node with a raise constraint error. This will properly
2513 -- propagate Raises_Constraint_Error since this flag is set in Result.
2515 if Raises_Constraint_Error
(Result
) then
2516 Rewrite_In_Raise_CE
(N
, Result
);
2517 Check_Non_Static_Context
(Non_Result
);
2519 -- Otherwise the result operand replaces the original node
2522 Rewrite
(N
, Relocate_Node
(Result
));
2523 Set_Is_Static_Expression
(N
);
2525 end Eval_If_Expression
;
2527 ----------------------------
2528 -- Eval_Indexed_Component --
2529 ----------------------------
2531 -- Indexed components are never static, so we need to perform the check
2532 -- for non-static context on the index values. Then, we check if the
2533 -- value can be obtained at compile time, even though it is non-static.
2535 procedure Eval_Indexed_Component
(N
: Node_Id
) is
2539 -- Check for non-static context on index values
2541 Expr
:= First
(Expressions
(N
));
2542 while Present
(Expr
) loop
2543 Check_Non_Static_Context
(Expr
);
2547 -- If the indexed component appears in an object renaming declaration
2548 -- then we do not want to try to evaluate it, since in this case we
2549 -- need the identity of the array element.
2551 if Nkind
(Parent
(N
)) = N_Object_Renaming_Declaration
then
2554 -- Similarly if the indexed component appears as the prefix of an
2555 -- attribute we don't want to evaluate it, because at least for
2556 -- some cases of attributes we need the identify (e.g. Access, Size)
2558 elsif Nkind
(Parent
(N
)) = N_Attribute_Reference
then
2562 -- Note: there are other cases, such as the left side of an assignment,
2563 -- or an OUT parameter for a call, where the replacement results in the
2564 -- illegal use of a constant, But these cases are illegal in the first
2565 -- place, so the replacement, though silly, is harmless.
2567 -- Now see if this is a constant array reference
2569 if List_Length
(Expressions
(N
)) = 1
2570 and then Is_Entity_Name
(Prefix
(N
))
2571 and then Ekind
(Entity
(Prefix
(N
))) = E_Constant
2572 and then Present
(Constant_Value
(Entity
(Prefix
(N
))))
2575 Loc
: constant Source_Ptr
:= Sloc
(N
);
2576 Arr
: constant Node_Id
:= Constant_Value
(Entity
(Prefix
(N
)));
2577 Sub
: constant Node_Id
:= First
(Expressions
(N
));
2583 -- Linear one's origin subscript value for array reference
2586 -- Lower bound of the first array index
2589 -- Value from constant array
2592 Atyp
:= Etype
(Arr
);
2594 if Is_Access_Type
(Atyp
) then
2595 Atyp
:= Designated_Type
(Atyp
);
2598 -- If we have an array type (we should have but perhaps there are
2599 -- error cases where this is not the case), then see if we can do
2600 -- a constant evaluation of the array reference.
2602 if Is_Array_Type
(Atyp
) and then Atyp
/= Any_Composite
then
2603 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
2604 Lbd
:= String_Literal_Low_Bound
(Atyp
);
2606 Lbd
:= Type_Low_Bound
(Etype
(First_Index
(Atyp
)));
2609 if Compile_Time_Known_Value
(Sub
)
2610 and then Nkind
(Arr
) = N_Aggregate
2611 and then Compile_Time_Known_Value
(Lbd
)
2612 and then Is_Discrete_Type
(Component_Type
(Atyp
))
2614 Lin
:= UI_To_Int
(Expr_Value
(Sub
) - Expr_Value
(Lbd
)) + 1;
2616 if List_Length
(Expressions
(Arr
)) >= Lin
then
2617 Elm
:= Pick
(Expressions
(Arr
), Lin
);
2619 -- If the resulting expression is compile time known,
2620 -- then we can rewrite the indexed component with this
2621 -- value, being sure to mark the result as non-static.
2622 -- We also reset the Sloc, in case this generates an
2623 -- error later on (e.g. 136'Access).
2625 if Compile_Time_Known_Value
(Elm
) then
2626 Rewrite
(N
, Duplicate_Subexpr_No_Checks
(Elm
));
2627 Set_Is_Static_Expression
(N
, False);
2632 -- We can also constant-fold if the prefix is a string literal.
2633 -- This will be useful in an instantiation or an inlining.
2635 elsif Compile_Time_Known_Value
(Sub
)
2636 and then Nkind
(Arr
) = N_String_Literal
2637 and then Compile_Time_Known_Value
(Lbd
)
2638 and then Expr_Value
(Lbd
) = 1
2639 and then Expr_Value
(Sub
) <=
2640 String_Literal_Length
(Etype
(Arr
))
2643 C
: constant Char_Code
:=
2644 Get_String_Char
(Strval
(Arr
),
2645 UI_To_Int
(Expr_Value
(Sub
)));
2647 Set_Character_Literal_Name
(C
);
2650 Make_Character_Literal
(Loc
,
2652 Char_Literal_Value
=> UI_From_CC
(C
));
2653 Set_Etype
(Elm
, Component_Type
(Atyp
));
2654 Rewrite
(N
, Duplicate_Subexpr_No_Checks
(Elm
));
2655 Set_Is_Static_Expression
(N
, False);
2661 end Eval_Indexed_Component
;
2663 --------------------------
2664 -- Eval_Integer_Literal --
2665 --------------------------
2667 -- Numeric literals are static (RM 4.9(1)), and have already been marked
2668 -- as static by the analyzer. The reason we did it that early is to allow
2669 -- the possibility of turning off the Is_Static_Expression flag after
2670 -- analysis, but before resolution, when integer literals are generated in
2671 -- the expander that do not correspond to static expressions.
2673 procedure Eval_Integer_Literal
(N
: Node_Id
) is
2674 T
: constant Entity_Id
:= Etype
(N
);
2676 function In_Any_Integer_Context
return Boolean;
2677 -- If the literal is resolved with a specific type in a context where
2678 -- the expected type is Any_Integer, there are no range checks on the
2679 -- literal. By the time the literal is evaluated, it carries the type
2680 -- imposed by the enclosing expression, and we must recover the context
2681 -- to determine that Any_Integer is meant.
2683 ----------------------------
2684 -- In_Any_Integer_Context --
2685 ----------------------------
2687 function In_Any_Integer_Context
return Boolean is
2688 Par
: constant Node_Id
:= Parent
(N
);
2689 K
: constant Node_Kind
:= Nkind
(Par
);
2692 -- Any_Integer also appears in digits specifications for real types,
2693 -- but those have bounds smaller that those of any integer base type,
2694 -- so we can safely ignore these cases.
2696 return Nkind_In
(K
, N_Number_Declaration
,
2697 N_Attribute_Reference
,
2698 N_Attribute_Definition_Clause
,
2699 N_Modular_Type_Definition
,
2700 N_Signed_Integer_Type_Definition
);
2701 end In_Any_Integer_Context
;
2703 -- Start of processing for Eval_Integer_Literal
2707 -- If the literal appears in a non-expression context, then it is
2708 -- certainly appearing in a non-static context, so check it. This is
2709 -- actually a redundant check, since Check_Non_Static_Context would
2710 -- check it, but it seems worthwhile to optimize out the call.
2712 -- An exception is made for a literal in an if or case expression
2714 if (Nkind_In
(Parent
(N
), N_If_Expression
, N_Case_Expression_Alternative
)
2715 or else Nkind
(Parent
(N
)) not in N_Subexpr
)
2716 and then not In_Any_Integer_Context
2718 Check_Non_Static_Context
(N
);
2721 -- Modular integer literals must be in their base range
2723 if Is_Modular_Integer_Type
(T
)
2724 and then Is_Out_Of_Range
(N
, Base_Type
(T
), Assume_Valid
=> True)
2728 end Eval_Integer_Literal
;
2730 ---------------------
2731 -- Eval_Logical_Op --
2732 ---------------------
2734 -- Logical operations are static functions, so the result is potentially
2735 -- static if both operands are potentially static (RM 4.9(7), 4.9(20)).
2737 procedure Eval_Logical_Op
(N
: Node_Id
) is
2738 Left
: constant Node_Id
:= Left_Opnd
(N
);
2739 Right
: constant Node_Id
:= Right_Opnd
(N
);
2744 -- If not foldable we are done
2746 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
2752 -- Compile time evaluation of logical operation
2755 Left_Int
: constant Uint
:= Expr_Value
(Left
);
2756 Right_Int
: constant Uint
:= Expr_Value
(Right
);
2759 if Is_Modular_Integer_Type
(Etype
(N
)) then
2761 Left_Bits
: Bits
(0 .. UI_To_Int
(Esize
(Etype
(N
))) - 1);
2762 Right_Bits
: Bits
(0 .. UI_To_Int
(Esize
(Etype
(N
))) - 1);
2765 To_Bits
(Left_Int
, Left_Bits
);
2766 To_Bits
(Right_Int
, Right_Bits
);
2768 -- Note: should really be able to use array ops instead of
2769 -- these loops, but they weren't working at the time ???
2771 if Nkind
(N
) = N_Op_And
then
2772 for J
in Left_Bits
'Range loop
2773 Left_Bits
(J
) := Left_Bits
(J
) and Right_Bits
(J
);
2776 elsif Nkind
(N
) = N_Op_Or
then
2777 for J
in Left_Bits
'Range loop
2778 Left_Bits
(J
) := Left_Bits
(J
) or Right_Bits
(J
);
2782 pragma Assert
(Nkind
(N
) = N_Op_Xor
);
2784 for J
in Left_Bits
'Range loop
2785 Left_Bits
(J
) := Left_Bits
(J
) xor Right_Bits
(J
);
2789 Fold_Uint
(N
, From_Bits
(Left_Bits
, Etype
(N
)), Stat
);
2793 pragma Assert
(Is_Boolean_Type
(Etype
(N
)));
2795 if Nkind
(N
) = N_Op_And
then
2797 Test
(Is_True
(Left_Int
) and then Is_True
(Right_Int
)), Stat
);
2799 elsif Nkind
(N
) = N_Op_Or
then
2801 Test
(Is_True
(Left_Int
) or else Is_True
(Right_Int
)), Stat
);
2804 pragma Assert
(Nkind
(N
) = N_Op_Xor
);
2806 Test
(Is_True
(Left_Int
) xor Is_True
(Right_Int
)), Stat
);
2810 end Eval_Logical_Op
;
2812 ------------------------
2813 -- Eval_Membership_Op --
2814 ------------------------
2816 -- A membership test is potentially static if the expression is static, and
2817 -- the range is a potentially static range, or is a subtype mark denoting a
2818 -- static subtype (RM 4.9(12)).
2820 procedure Eval_Membership_Op
(N
: Node_Id
) is
2821 Alts
: constant List_Id
:= Alternatives
(N
);
2822 Choice
: constant Node_Id
:= Right_Opnd
(N
);
2823 Expr
: constant Node_Id
:= Left_Opnd
(N
);
2824 Result
: Match_Result
;
2827 -- Ignore if error in either operand, except to make sure that Any_Type
2828 -- is properly propagated to avoid junk cascaded errors.
2830 if Etype
(Expr
) = Any_Type
2831 or else (Present
(Choice
) and then Etype
(Choice
) = Any_Type
)
2833 Set_Etype
(N
, Any_Type
);
2837 -- If left operand non-static, then nothing to do
2839 if not Is_Static_Expression
(Expr
) then
2843 -- If choice is non-static, left operand is in non-static context
2845 if (Present
(Choice
) and then not Is_Static_Choice
(Choice
))
2846 or else (Present
(Alts
) and then not Is_Static_Choice_List
(Alts
))
2848 Check_Non_Static_Context
(Expr
);
2852 -- Otherwise we definitely have a static expression
2854 Set_Is_Static_Expression
(N
);
2856 -- If left operand raises constraint error, propagate and we are done
2858 if Raises_Constraint_Error
(Expr
) then
2859 Set_Raises_Constraint_Error
(N
, True);
2864 if Present
(Choice
) then
2865 Result
:= Choice_Matches
(Expr
, Choice
);
2867 Result
:= Choices_Match
(Expr
, Alts
);
2870 -- If result is Non_Static, it means that we raise Constraint_Error,
2871 -- since we already tested that the operands were themselves static.
2873 if Result
= Non_Static
then
2874 Set_Raises_Constraint_Error
(N
);
2876 -- Otherwise we have our result (flipped if NOT IN case)
2880 (N
, Test
((Result
= Match
) xor (Nkind
(N
) = N_Not_In
)), True);
2881 Warn_On_Known_Condition
(N
);
2884 end Eval_Membership_Op
;
2886 ------------------------
2887 -- Eval_Named_Integer --
2888 ------------------------
2890 procedure Eval_Named_Integer
(N
: Node_Id
) is
2893 Expr_Value
(Expression
(Declaration_Node
(Entity
(N
)))), True);
2894 end Eval_Named_Integer
;
2896 ---------------------
2897 -- Eval_Named_Real --
2898 ---------------------
2900 procedure Eval_Named_Real
(N
: Node_Id
) is
2903 Expr_Value_R
(Expression
(Declaration_Node
(Entity
(N
)))), True);
2904 end Eval_Named_Real
;
2910 -- Exponentiation is a static functions, so the result is potentially
2911 -- static if both operands are potentially static (RM 4.9(7), 4.9(20)).
2913 procedure Eval_Op_Expon
(N
: Node_Id
) is
2914 Left
: constant Node_Id
:= Left_Opnd
(N
);
2915 Right
: constant Node_Id
:= Right_Opnd
(N
);
2920 -- If not foldable we are done
2922 Test_Expression_Is_Foldable
2923 (N
, Left
, Right
, Stat
, Fold
, CRT_Safe
=> True);
2925 -- Return if not foldable
2931 if Configurable_Run_Time_Mode
and not Stat
then
2935 -- Fold exponentiation operation
2938 Right_Int
: constant Uint
:= Expr_Value
(Right
);
2943 if Is_Integer_Type
(Etype
(Left
)) then
2945 Left_Int
: constant Uint
:= Expr_Value
(Left
);
2949 -- Exponentiation of an integer raises Constraint_Error for a
2950 -- negative exponent (RM 4.5.6).
2952 if Right_Int
< 0 then
2953 Apply_Compile_Time_Constraint_Error
2954 (N
, "integer exponent negative", CE_Range_Check_Failed
,
2959 if OK_Bits
(N
, Num_Bits
(Left_Int
) * Right_Int
) then
2960 Result
:= Left_Int
** Right_Int
;
2965 if Is_Modular_Integer_Type
(Etype
(N
)) then
2966 Result
:= Result
mod Modulus
(Etype
(N
));
2969 Fold_Uint
(N
, Result
, Stat
);
2977 Left_Real
: constant Ureal
:= Expr_Value_R
(Left
);
2980 -- Cannot have a zero base with a negative exponent
2982 if UR_Is_Zero
(Left_Real
) then
2984 if Right_Int
< 0 then
2985 Apply_Compile_Time_Constraint_Error
2986 (N
, "zero ** negative integer", CE_Range_Check_Failed
,
2990 Fold_Ureal
(N
, Ureal_0
, Stat
);
2994 Fold_Ureal
(N
, Left_Real
** Right_Int
, Stat
);
3005 -- The not operation is a static functions, so the result is potentially
3006 -- static if the operand is potentially static (RM 4.9(7), 4.9(20)).
3008 procedure Eval_Op_Not
(N
: Node_Id
) is
3009 Right
: constant Node_Id
:= Right_Opnd
(N
);
3014 -- If not foldable we are done
3016 Test_Expression_Is_Foldable
(N
, Right
, Stat
, Fold
);
3022 -- Fold not operation
3025 Rint
: constant Uint
:= Expr_Value
(Right
);
3026 Typ
: constant Entity_Id
:= Etype
(N
);
3029 -- Negation is equivalent to subtracting from the modulus minus one.
3030 -- For a binary modulus this is equivalent to the ones-complement of
3031 -- the original value. For a nonbinary modulus this is an arbitrary
3032 -- but consistent definition.
3034 if Is_Modular_Integer_Type
(Typ
) then
3035 Fold_Uint
(N
, Modulus
(Typ
) - 1 - Rint
, Stat
);
3036 else pragma Assert
(Is_Boolean_Type
(Typ
));
3037 Fold_Uint
(N
, Test
(not Is_True
(Rint
)), Stat
);
3040 Set_Is_Static_Expression
(N
, Stat
);
3044 -------------------------------
3045 -- Eval_Qualified_Expression --
3046 -------------------------------
3048 -- A qualified expression is potentially static if its subtype mark denotes
3049 -- a static subtype and its expression is potentially static (RM 4.9 (11)).
3051 procedure Eval_Qualified_Expression
(N
: Node_Id
) is
3052 Operand
: constant Node_Id
:= Expression
(N
);
3053 Target_Type
: constant Entity_Id
:= Entity
(Subtype_Mark
(N
));
3060 -- Can only fold if target is string or scalar and subtype is static.
3061 -- Also, do not fold if our parent is an allocator (this is because the
3062 -- qualified expression is really part of the syntactic structure of an
3063 -- allocator, and we do not want to end up with something that
3064 -- corresponds to "new 1" where the 1 is the result of folding a
3065 -- qualified expression).
3067 if not Is_Static_Subtype
(Target_Type
)
3068 or else Nkind
(Parent
(N
)) = N_Allocator
3070 Check_Non_Static_Context
(Operand
);
3072 -- If operand is known to raise constraint_error, set the flag on the
3073 -- expression so it does not get optimized away.
3075 if Nkind
(Operand
) = N_Raise_Constraint_Error
then
3076 Set_Raises_Constraint_Error
(N
);
3082 -- If not foldable we are done
3084 Test_Expression_Is_Foldable
(N
, Operand
, Stat
, Fold
);
3089 -- Don't try fold if target type has constraint error bounds
3091 elsif not Is_OK_Static_Subtype
(Target_Type
) then
3092 Set_Raises_Constraint_Error
(N
);
3096 -- Here we will fold, save Print_In_Hex indication
3098 Hex
:= Nkind
(Operand
) = N_Integer_Literal
3099 and then Print_In_Hex
(Operand
);
3101 -- Fold the result of qualification
3103 if Is_Discrete_Type
(Target_Type
) then
3104 Fold_Uint
(N
, Expr_Value
(Operand
), Stat
);
3106 -- Preserve Print_In_Hex indication
3108 if Hex
and then Nkind
(N
) = N_Integer_Literal
then
3109 Set_Print_In_Hex
(N
);
3112 elsif Is_Real_Type
(Target_Type
) then
3113 Fold_Ureal
(N
, Expr_Value_R
(Operand
), Stat
);
3116 Fold_Str
(N
, Strval
(Get_String_Val
(Operand
)), Stat
);
3119 Set_Is_Static_Expression
(N
, False);
3121 Check_String_Literal_Length
(N
, Target_Type
);
3127 -- The expression may be foldable but not static
3129 Set_Is_Static_Expression
(N
, Stat
);
3131 if Is_Out_Of_Range
(N
, Etype
(N
), Assume_Valid
=> True) then
3134 end Eval_Qualified_Expression
;
3136 -----------------------
3137 -- Eval_Real_Literal --
3138 -----------------------
3140 -- Numeric literals are static (RM 4.9(1)), and have already been marked
3141 -- as static by the analyzer. The reason we did it that early is to allow
3142 -- the possibility of turning off the Is_Static_Expression flag after
3143 -- analysis, but before resolution, when integer literals are generated
3144 -- in the expander that do not correspond to static expressions.
3146 procedure Eval_Real_Literal
(N
: Node_Id
) is
3147 PK
: constant Node_Kind
:= Nkind
(Parent
(N
));
3150 -- If the literal appears in a non-expression context and not as part of
3151 -- a number declaration, then it is appearing in a non-static context,
3154 if PK
not in N_Subexpr
and then PK
/= N_Number_Declaration
then
3155 Check_Non_Static_Context
(N
);
3157 end Eval_Real_Literal
;
3159 ------------------------
3160 -- Eval_Relational_Op --
3161 ------------------------
3163 -- Relational operations are static functions, so the result is static if
3164 -- both operands are static (RM 4.9(7), 4.9(20)), except that for strings,
3165 -- the result is never static, even if the operands are.
3167 -- However, for internally generated nodes, we allow string equality and
3168 -- inequality to be static. This is because we rewrite A in "ABC" as an
3169 -- equality test A = "ABC", and the former is definitely static.
3171 procedure Eval_Relational_Op
(N
: Node_Id
) is
3172 Left
: constant Node_Id
:= Left_Opnd
(N
);
3173 Right
: constant Node_Id
:= Right_Opnd
(N
);
3175 procedure Decompose_Expr
3177 Ent
: out Entity_Id
;
3178 Kind
: out Character;
3180 Orig
: Boolean := True);
3181 -- Given expression Expr, see if it is of the form X [+/- K]. If so, Ent
3182 -- is set to the entity in X, Kind is 'F','L','E' for 'First or 'Last or
3183 -- simple entity, and Cons is the value of K. If the expression is not
3184 -- of the required form, Ent is set to Empty.
3186 -- Orig indicates whether Expr is the original expression to consider,
3187 -- or if we are handling a subexpression (e.g. recursive call to
3190 procedure Fold_General_Op
(Is_Static
: Boolean);
3191 -- Attempt to fold arbitrary relational operator N. Flag Is_Static must
3192 -- be set when the operator denotes a static expression.
3194 procedure Fold_Static_Real_Op
;
3195 -- Attempt to fold static real type relational operator N
3197 function Static_Length
(Expr
: Node_Id
) return Uint
;
3198 -- If Expr is an expression for a constrained array whose length is
3199 -- known at compile time, return the non-negative length, otherwise
3202 --------------------
3203 -- Decompose_Expr --
3204 --------------------
3206 procedure Decompose_Expr
3208 Ent
: out Entity_Id
;
3209 Kind
: out Character;
3211 Orig
: Boolean := True)
3216 -- Assume that the expression does not meet the expected form
3222 if Nkind
(Expr
) = N_Op_Add
3223 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
3225 Exp
:= Left_Opnd
(Expr
);
3226 Cons
:= Expr_Value
(Right_Opnd
(Expr
));
3228 elsif Nkind
(Expr
) = N_Op_Subtract
3229 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
3231 Exp
:= Left_Opnd
(Expr
);
3232 Cons
:= -Expr_Value
(Right_Opnd
(Expr
));
3234 -- If the bound is a constant created to remove side effects, recover
3235 -- the original expression to see if it has one of the recognizable
3238 elsif Nkind
(Expr
) = N_Identifier
3239 and then not Comes_From_Source
(Entity
(Expr
))
3240 and then Ekind
(Entity
(Expr
)) = E_Constant
3241 and then Nkind
(Parent
(Entity
(Expr
))) = N_Object_Declaration
3243 Exp
:= Expression
(Parent
(Entity
(Expr
)));
3244 Decompose_Expr
(Exp
, Ent
, Kind
, Cons
, Orig
=> False);
3246 -- If original expression includes an entity, create a reference
3247 -- to it for use below.
3249 if Present
(Ent
) then
3250 Exp
:= New_Occurrence_Of
(Ent
, Sloc
(Ent
));
3256 -- Only consider the case of X + 0 for a full expression, and
3257 -- not when recursing, otherwise we may end up with evaluating
3258 -- expressions not known at compile time to 0.
3268 -- At this stage Exp is set to the potential X
3270 if Nkind
(Exp
) = N_Attribute_Reference
then
3271 if Attribute_Name
(Exp
) = Name_First
then
3273 elsif Attribute_Name
(Exp
) = Name_Last
then
3279 Exp
:= Prefix
(Exp
);
3285 if Is_Entity_Name
(Exp
) and then Present
(Entity
(Exp
)) then
3286 Ent
:= Entity
(Exp
);
3290 ---------------------
3291 -- Fold_General_Op --
3292 ---------------------
3294 procedure Fold_General_Op
(Is_Static
: Boolean) is
3295 CR
: constant Compare_Result
:=
3296 Compile_Time_Compare
(Left
, Right
, Assume_Valid
=> False);
3301 if CR
= Unknown
then
3309 elsif CR
= NE
or else CR
= GT
or else CR
= LT
then
3316 if CR
= GT
or else CR
= EQ
or else CR
= GE
then
3327 elsif CR
= EQ
or else CR
= LT
or else CR
= LE
then
3334 if CR
= LT
or else CR
= EQ
or else CR
= LE
then
3345 elsif CR
= EQ
or else CR
= GT
or else CR
= GE
then
3352 if CR
= NE
or else CR
= GT
or else CR
= LT
then
3361 raise Program_Error
;
3364 -- Determine the potential outcome of the relation assuming the
3365 -- operands are valid and emit a warning when the relation yields
3366 -- True or False only in the presence of invalid values.
3368 Warn_On_Constant_Valid_Condition
(N
);
3370 Fold_Uint
(N
, Test
(Result
), Is_Static
);
3371 end Fold_General_Op
;
3373 -------------------------
3374 -- Fold_Static_Real_Op --
3375 -------------------------
3377 procedure Fold_Static_Real_Op
is
3378 Left_Real
: constant Ureal
:= Expr_Value_R
(Left
);
3379 Right_Real
: constant Ureal
:= Expr_Value_R
(Right
);
3384 when N_Op_Eq
=> Result
:= (Left_Real
= Right_Real
);
3385 when N_Op_Ge
=> Result
:= (Left_Real
>= Right_Real
);
3386 when N_Op_Gt
=> Result
:= (Left_Real
> Right_Real
);
3387 when N_Op_Le
=> Result
:= (Left_Real
<= Right_Real
);
3388 when N_Op_Lt
=> Result
:= (Left_Real
< Right_Real
);
3389 when N_Op_Ne
=> Result
:= (Left_Real
/= Right_Real
);
3390 when others => raise Program_Error
;
3393 Fold_Uint
(N
, Test
(Result
), True);
3394 end Fold_Static_Real_Op
;
3400 function Static_Length
(Expr
: Node_Id
) return Uint
is
3410 -- First easy case string literal
3412 if Nkind
(Expr
) = N_String_Literal
then
3413 return UI_From_Int
(String_Length
(Strval
(Expr
)));
3415 -- With frontend inlining as performed in GNATprove mode, a variable
3416 -- may be inserted that has a string literal subtype. Deal with this
3417 -- specially as for the previous case.
3419 elsif Ekind
(Etype
(Expr
)) = E_String_Literal_Subtype
then
3420 return String_Literal_Length
(Etype
(Expr
));
3422 -- Second easy case, not constrained subtype, so no length
3424 elsif not Is_Constrained
(Etype
(Expr
)) then
3425 return Uint_Minus_1
;
3430 Typ
:= Etype
(First_Index
(Etype
(Expr
)));
3432 -- The simple case, both bounds are known at compile time
3434 if Is_Discrete_Type
(Typ
)
3435 and then Compile_Time_Known_Value
(Type_Low_Bound
(Typ
))
3436 and then Compile_Time_Known_Value
(Type_High_Bound
(Typ
))
3439 UI_Max
(Uint_0
, Expr_Value
(Type_High_Bound
(Typ
)) -
3440 Expr_Value
(Type_Low_Bound
(Typ
)) + 1);
3443 -- A more complex case, where the bounds are of the form X [+/- K1]
3444 -- .. X [+/- K2]), where X is an expression that is either A'First or
3445 -- A'Last (with A an entity name), or X is an entity name, and the
3446 -- two X's are the same and K1 and K2 are known at compile time, in
3447 -- this case, the length can also be computed at compile time, even
3448 -- though the bounds are not known. A common case of this is e.g.
3449 -- (X'First .. X'First+5).
3452 (Original_Node
(Type_Low_Bound
(Typ
)), Ent1
, Kind1
, Cons1
);
3454 (Original_Node
(Type_High_Bound
(Typ
)), Ent2
, Kind2
, Cons2
);
3456 if Present
(Ent1
) and then Ent1
= Ent2
and then Kind1
= Kind2
then
3457 return Cons2
- Cons1
+ 1;
3459 return Uint_Minus_1
;
3465 Left_Typ
: constant Entity_Id
:= Etype
(Left
);
3466 Right_Typ
: constant Entity_Id
:= Etype
(Right
);
3469 Op_Typ
: Entity_Id
:= Empty
;
3472 Is_Static_Expression
: Boolean;
3474 -- Start of processing for Eval_Relational_Op
3477 -- One special case to deal with first. If we can tell that the result
3478 -- will be false because the lengths of one or more index subtypes are
3479 -- compile-time known and different, then we can replace the entire
3480 -- result by False. We only do this for one-dimensional arrays, because
3481 -- the case of multidimensional arrays is rare and too much trouble. If
3482 -- one of the operands is an illegal aggregate, its type might still be
3483 -- an arbitrary composite type, so nothing to do.
3485 if Is_Array_Type
(Left_Typ
)
3486 and then Left_Typ
/= Any_Composite
3487 and then Number_Dimensions
(Left_Typ
) = 1
3488 and then Nkind_In
(N
, N_Op_Eq
, N_Op_Ne
)
3490 if Raises_Constraint_Error
(Left
)
3492 Raises_Constraint_Error
(Right
)
3496 -- OK, we have the case where we may be able to do this fold
3499 Left_Len
:= Static_Length
(Left
);
3500 Right_Len
:= Static_Length
(Right
);
3502 if Left_Len
/= Uint_Minus_1
3503 and then Right_Len
/= Uint_Minus_1
3504 and then Left_Len
/= Right_Len
3506 Fold_Uint
(N
, Test
(Nkind
(N
) = N_Op_Ne
), False);
3507 Warn_On_Known_Condition
(N
);
3515 -- Initialize the value of Is_Static_Expression. The value of Fold
3516 -- returned by Test_Expression_Is_Foldable is not needed since, even
3517 -- when some operand is a variable, we can still perform the static
3518 -- evaluation of the expression in some cases (for example, for a
3519 -- variable of a subtype of Integer we statically know that any value
3520 -- stored in such variable is smaller than Integer'Last).
3522 Test_Expression_Is_Foldable
3523 (N
, Left
, Right
, Is_Static_Expression
, Fold
);
3525 -- Only comparisons of scalars can give static results. A comparison
3526 -- of strings never yields a static result, even if both operands are
3527 -- static strings, except that as noted above, we allow equality and
3528 -- inequality for strings.
3530 if Is_String_Type
(Left_Typ
)
3531 and then not Comes_From_Source
(N
)
3532 and then Nkind_In
(N
, N_Op_Eq
, N_Op_Ne
)
3536 elsif not Is_Scalar_Type
(Left_Typ
) then
3537 Is_Static_Expression
:= False;
3538 Set_Is_Static_Expression
(N
, False);
3541 -- For operators on universal numeric types called as functions with
3542 -- an explicit scope, determine appropriate specific numeric type,
3543 -- and diagnose possible ambiguity.
3545 if Is_Universal_Numeric_Type
(Left_Typ
)
3547 Is_Universal_Numeric_Type
(Right_Typ
)
3549 Op_Typ
:= Find_Universal_Operator_Type
(N
);
3552 -- Attempt to fold the relational operator
3554 if Is_Static_Expression
and then Is_Real_Type
(Left_Typ
) then
3555 Fold_Static_Real_Op
;
3557 Fold_General_Op
(Is_Static_Expression
);
3561 -- For the case of a folded relational operator on a specific numeric
3562 -- type, freeze the operand type now.
3564 if Present
(Op_Typ
) then
3565 Freeze_Before
(N
, Op_Typ
);
3568 Warn_On_Known_Condition
(N
);
3569 end Eval_Relational_Op
;
3575 -- Shift operations are intrinsic operations that can never be static, so
3576 -- the only processing required is to perform the required check for a non
3577 -- static context for the two operands.
3579 -- Actually we could do some compile time evaluation here some time ???
3581 procedure Eval_Shift
(N
: Node_Id
) is
3583 Check_Non_Static_Context
(Left_Opnd
(N
));
3584 Check_Non_Static_Context
(Right_Opnd
(N
));
3587 ------------------------
3588 -- Eval_Short_Circuit --
3589 ------------------------
3591 -- A short circuit operation is potentially static if both operands are
3592 -- potentially static (RM 4.9 (13)).
3594 procedure Eval_Short_Circuit
(N
: Node_Id
) is
3595 Kind
: constant Node_Kind
:= Nkind
(N
);
3596 Left
: constant Node_Id
:= Left_Opnd
(N
);
3597 Right
: constant Node_Id
:= Right_Opnd
(N
);
3600 Rstat
: constant Boolean :=
3601 Is_Static_Expression
(Left
)
3603 Is_Static_Expression
(Right
);
3606 -- Short circuit operations are never static in Ada 83
3608 if Ada_Version
= Ada_83
and then Comes_From_Source
(N
) then
3609 Check_Non_Static_Context
(Left
);
3610 Check_Non_Static_Context
(Right
);
3614 -- Now look at the operands, we can't quite use the normal call to
3615 -- Test_Expression_Is_Foldable here because short circuit operations
3616 -- are a special case, they can still be foldable, even if the right
3617 -- operand raises constraint error.
3619 -- If either operand is Any_Type, just propagate to result and do not
3620 -- try to fold, this prevents cascaded errors.
3622 if Etype
(Left
) = Any_Type
or else Etype
(Right
) = Any_Type
then
3623 Set_Etype
(N
, Any_Type
);
3626 -- If left operand raises constraint error, then replace node N with
3627 -- the raise constraint error node, and we are obviously not foldable.
3628 -- Is_Static_Expression is set from the two operands in the normal way,
3629 -- and we check the right operand if it is in a non-static context.
3631 elsif Raises_Constraint_Error
(Left
) then
3633 Check_Non_Static_Context
(Right
);
3636 Rewrite_In_Raise_CE
(N
, Left
);
3637 Set_Is_Static_Expression
(N
, Rstat
);
3640 -- If the result is not static, then we won't in any case fold
3642 elsif not Rstat
then
3643 Check_Non_Static_Context
(Left
);
3644 Check_Non_Static_Context
(Right
);
3648 -- Here the result is static, note that, unlike the normal processing
3649 -- in Test_Expression_Is_Foldable, we did *not* check above to see if
3650 -- the right operand raises constraint error, that's because it is not
3651 -- significant if the left operand is decisive.
3653 Set_Is_Static_Expression
(N
);
3655 -- It does not matter if the right operand raises constraint error if
3656 -- it will not be evaluated. So deal specially with the cases where
3657 -- the right operand is not evaluated. Note that we will fold these
3658 -- cases even if the right operand is non-static, which is fine, but
3659 -- of course in these cases the result is not potentially static.
3661 Left_Int
:= Expr_Value
(Left
);
3663 if (Kind
= N_And_Then
and then Is_False
(Left_Int
))
3665 (Kind
= N_Or_Else
and then Is_True
(Left_Int
))
3667 Fold_Uint
(N
, Left_Int
, Rstat
);
3671 -- If first operand not decisive, then it does matter if the right
3672 -- operand raises constraint error, since it will be evaluated, so
3673 -- we simply replace the node with the right operand. Note that this
3674 -- properly propagates Is_Static_Expression and Raises_Constraint_Error
3675 -- (both are set to True in Right).
3677 if Raises_Constraint_Error
(Right
) then
3678 Rewrite_In_Raise_CE
(N
, Right
);
3679 Check_Non_Static_Context
(Left
);
3683 -- Otherwise the result depends on the right operand
3685 Fold_Uint
(N
, Expr_Value
(Right
), Rstat
);
3687 end Eval_Short_Circuit
;
3693 -- Slices can never be static, so the only processing required is to check
3694 -- for non-static context if an explicit range is given.
3696 procedure Eval_Slice
(N
: Node_Id
) is
3697 Drange
: constant Node_Id
:= Discrete_Range
(N
);
3700 if Nkind
(Drange
) = N_Range
then
3701 Check_Non_Static_Context
(Low_Bound
(Drange
));
3702 Check_Non_Static_Context
(High_Bound
(Drange
));
3705 -- A slice of the form A (subtype), when the subtype is the index of
3706 -- the type of A, is redundant, the slice can be replaced with A, and
3707 -- this is worth a warning.
3709 if Is_Entity_Name
(Prefix
(N
)) then
3711 E
: constant Entity_Id
:= Entity
(Prefix
(N
));
3712 T
: constant Entity_Id
:= Etype
(E
);
3715 if Ekind
(E
) = E_Constant
3716 and then Is_Array_Type
(T
)
3717 and then Is_Entity_Name
(Drange
)
3719 if Is_Entity_Name
(Original_Node
(First_Index
(T
)))
3720 and then Entity
(Original_Node
(First_Index
(T
)))
3723 if Warn_On_Redundant_Constructs
then
3724 Error_Msg_N
("redundant slice denotes whole array?r?", N
);
3727 -- The following might be a useful optimization???
3729 -- Rewrite (N, New_Occurrence_Of (E, Sloc (N)));
3736 -------------------------
3737 -- Eval_String_Literal --
3738 -------------------------
3740 procedure Eval_String_Literal
(N
: Node_Id
) is
3741 Typ
: constant Entity_Id
:= Etype
(N
);
3742 Bas
: constant Entity_Id
:= Base_Type
(Typ
);
3748 -- Nothing to do if error type (handles cases like default expressions
3749 -- or generics where we have not yet fully resolved the type).
3751 if Bas
= Any_Type
or else Bas
= Any_String
then
3755 -- String literals are static if the subtype is static (RM 4.9(2)), so
3756 -- reset the static expression flag (it was set unconditionally in
3757 -- Analyze_String_Literal) if the subtype is non-static. We tell if
3758 -- the subtype is static by looking at the lower bound.
3760 if Ekind
(Typ
) = E_String_Literal_Subtype
then
3761 if not Is_OK_Static_Expression
(String_Literal_Low_Bound
(Typ
)) then
3762 Set_Is_Static_Expression
(N
, False);
3766 -- Here if Etype of string literal is normal Etype (not yet possible,
3767 -- but may be possible in future).
3769 elsif not Is_OK_Static_Expression
3770 (Type_Low_Bound
(Etype
(First_Index
(Typ
))))
3772 Set_Is_Static_Expression
(N
, False);
3776 -- If original node was a type conversion, then result if non-static
3778 if Nkind
(Original_Node
(N
)) = N_Type_Conversion
then
3779 Set_Is_Static_Expression
(N
, False);
3783 -- Test for illegal Ada 95 cases. A string literal is illegal in Ada 95
3784 -- if its bounds are outside the index base type and this index type is
3785 -- static. This can happen in only two ways. Either the string literal
3786 -- is too long, or it is null, and the lower bound is type'First. Either
3787 -- way it is the upper bound that is out of range of the index type.
3789 if Ada_Version
>= Ada_95
then
3790 if Is_Standard_String_Type
(Bas
) then
3791 Xtp
:= Standard_Positive
;
3793 Xtp
:= Etype
(First_Index
(Bas
));
3796 if Ekind
(Typ
) = E_String_Literal_Subtype
then
3797 Lo
:= String_Literal_Low_Bound
(Typ
);
3799 Lo
:= Type_Low_Bound
(Etype
(First_Index
(Typ
)));
3802 -- Check for string too long
3804 Len
:= String_Length
(Strval
(N
));
3806 if UI_From_Int
(Len
) > String_Type_Len
(Bas
) then
3808 -- Issue message. Note that this message is a warning if the
3809 -- string literal is not marked as static (happens in some cases
3810 -- of folding strings known at compile time, but not static).
3811 -- Furthermore in such cases, we reword the message, since there
3812 -- is no string literal in the source program.
3814 if Is_Static_Expression
(N
) then
3815 Apply_Compile_Time_Constraint_Error
3816 (N
, "string literal too long for}", CE_Length_Check_Failed
,
3818 Typ
=> First_Subtype
(Bas
));
3820 Apply_Compile_Time_Constraint_Error
3821 (N
, "string value too long for}", CE_Length_Check_Failed
,
3823 Typ
=> First_Subtype
(Bas
),
3827 -- Test for null string not allowed
3830 and then not Is_Generic_Type
(Xtp
)
3832 Expr_Value
(Lo
) = Expr_Value
(Type_Low_Bound
(Base_Type
(Xtp
)))
3834 -- Same specialization of message
3836 if Is_Static_Expression
(N
) then
3837 Apply_Compile_Time_Constraint_Error
3838 (N
, "null string literal not allowed for}",
3839 CE_Length_Check_Failed
,
3841 Typ
=> First_Subtype
(Bas
));
3843 Apply_Compile_Time_Constraint_Error
3844 (N
, "null string value not allowed for}",
3845 CE_Length_Check_Failed
,
3847 Typ
=> First_Subtype
(Bas
),
3852 end Eval_String_Literal
;
3854 --------------------------
3855 -- Eval_Type_Conversion --
3856 --------------------------
3858 -- A type conversion is potentially static if its subtype mark is for a
3859 -- static scalar subtype, and its operand expression is potentially static
3862 procedure Eval_Type_Conversion
(N
: Node_Id
) is
3863 Operand
: constant Node_Id
:= Expression
(N
);
3864 Source_Type
: constant Entity_Id
:= Etype
(Operand
);
3865 Target_Type
: constant Entity_Id
:= Etype
(N
);
3867 function To_Be_Treated_As_Integer
(T
: Entity_Id
) return Boolean;
3868 -- Returns true if type T is an integer type, or if it is a fixed-point
3869 -- type to be treated as an integer (i.e. the flag Conversion_OK is set
3870 -- on the conversion node).
3872 function To_Be_Treated_As_Real
(T
: Entity_Id
) return Boolean;
3873 -- Returns true if type T is a floating-point type, or if it is a
3874 -- fixed-point type that is not to be treated as an integer (i.e. the
3875 -- flag Conversion_OK is not set on the conversion node).
3877 ------------------------------
3878 -- To_Be_Treated_As_Integer --
3879 ------------------------------
3881 function To_Be_Treated_As_Integer
(T
: Entity_Id
) return Boolean is
3885 or else (Is_Fixed_Point_Type
(T
) and then Conversion_OK
(N
));
3886 end To_Be_Treated_As_Integer
;
3888 ---------------------------
3889 -- To_Be_Treated_As_Real --
3890 ---------------------------
3892 function To_Be_Treated_As_Real
(T
: Entity_Id
) return Boolean is
3895 Is_Floating_Point_Type
(T
)
3896 or else (Is_Fixed_Point_Type
(T
) and then not Conversion_OK
(N
));
3897 end To_Be_Treated_As_Real
;
3904 -- Start of processing for Eval_Type_Conversion
3907 -- Cannot fold if target type is non-static or if semantic error
3909 if not Is_Static_Subtype
(Target_Type
) then
3910 Check_Non_Static_Context
(Operand
);
3912 elsif Error_Posted
(N
) then
3916 -- If not foldable we are done
3918 Test_Expression_Is_Foldable
(N
, Operand
, Stat
, Fold
);
3923 -- Don't try fold if target type has constraint error bounds
3925 elsif not Is_OK_Static_Subtype
(Target_Type
) then
3926 Set_Raises_Constraint_Error
(N
);
3930 -- Remaining processing depends on operand types. Note that in the
3931 -- following type test, fixed-point counts as real unless the flag
3932 -- Conversion_OK is set, in which case it counts as integer.
3934 -- Fold conversion, case of string type. The result is not static
3936 if Is_String_Type
(Target_Type
) then
3937 Fold_Str
(N
, Strval
(Get_String_Val
(Operand
)), Static
=> False);
3940 -- Fold conversion, case of integer target type
3942 elsif To_Be_Treated_As_Integer
(Target_Type
) then
3947 -- Integer to integer conversion
3949 if To_Be_Treated_As_Integer
(Source_Type
) then
3950 Result
:= Expr_Value
(Operand
);
3952 -- Real to integer conversion
3955 Result
:= UR_To_Uint
(Expr_Value_R
(Operand
));
3958 -- If fixed-point type (Conversion_OK must be set), then the
3959 -- result is logically an integer, but we must replace the
3960 -- conversion with the corresponding real literal, since the
3961 -- type from a semantic point of view is still fixed-point.
3963 if Is_Fixed_Point_Type
(Target_Type
) then
3965 (N
, UR_From_Uint
(Result
) * Small_Value
(Target_Type
), Stat
);
3967 -- Otherwise result is integer literal
3970 Fold_Uint
(N
, Result
, Stat
);
3974 -- Fold conversion, case of real target type
3976 elsif To_Be_Treated_As_Real
(Target_Type
) then
3981 if To_Be_Treated_As_Real
(Source_Type
) then
3982 Result
:= Expr_Value_R
(Operand
);
3984 Result
:= UR_From_Uint
(Expr_Value
(Operand
));
3987 Fold_Ureal
(N
, Result
, Stat
);
3990 -- Enumeration types
3993 Fold_Uint
(N
, Expr_Value
(Operand
), Stat
);
3996 if Is_Out_Of_Range
(N
, Etype
(N
), Assume_Valid
=> True) then
4000 end Eval_Type_Conversion
;
4006 -- Predefined unary operators are static functions (RM 4.9(20)) and thus
4007 -- are potentially static if the operand is potentially static (RM 4.9(7)).
4009 procedure Eval_Unary_Op
(N
: Node_Id
) is
4010 Right
: constant Node_Id
:= Right_Opnd
(N
);
4011 Otype
: Entity_Id
:= Empty
;
4016 -- If not foldable we are done
4018 Test_Expression_Is_Foldable
(N
, Right
, Stat
, Fold
);
4024 if Etype
(Right
) = Universal_Integer
4026 Etype
(Right
) = Universal_Real
4028 Otype
:= Find_Universal_Operator_Type
(N
);
4031 -- Fold for integer case
4033 if Is_Integer_Type
(Etype
(N
)) then
4035 Rint
: constant Uint
:= Expr_Value
(Right
);
4039 -- In the case of modular unary plus and abs there is no need
4040 -- to adjust the result of the operation since if the original
4041 -- operand was in bounds the result will be in the bounds of the
4042 -- modular type. However, in the case of modular unary minus the
4043 -- result may go out of the bounds of the modular type and needs
4046 if Nkind
(N
) = N_Op_Plus
then
4049 elsif Nkind
(N
) = N_Op_Minus
then
4050 if Is_Modular_Integer_Type
(Etype
(N
)) then
4051 Result
:= (-Rint
) mod Modulus
(Etype
(N
));
4057 pragma Assert
(Nkind
(N
) = N_Op_Abs
);
4061 Fold_Uint
(N
, Result
, Stat
);
4064 -- Fold for real case
4066 elsif Is_Real_Type
(Etype
(N
)) then
4068 Rreal
: constant Ureal
:= Expr_Value_R
(Right
);
4072 if Nkind
(N
) = N_Op_Plus
then
4074 elsif Nkind
(N
) = N_Op_Minus
then
4075 Result
:= UR_Negate
(Rreal
);
4077 pragma Assert
(Nkind
(N
) = N_Op_Abs
);
4078 Result
:= abs Rreal
;
4081 Fold_Ureal
(N
, Result
, Stat
);
4085 -- If the operator was resolved to a specific type, make sure that type
4086 -- is frozen even if the expression is folded into a literal (which has
4087 -- a universal type).
4089 if Present
(Otype
) then
4090 Freeze_Before
(N
, Otype
);
4094 -------------------------------
4095 -- Eval_Unchecked_Conversion --
4096 -------------------------------
4098 -- Unchecked conversions can never be static, so the only required
4099 -- processing is to check for a non-static context for the operand.
4101 procedure Eval_Unchecked_Conversion
(N
: Node_Id
) is
4103 Check_Non_Static_Context
(Expression
(N
));
4104 end Eval_Unchecked_Conversion
;
4106 --------------------
4107 -- Expr_Rep_Value --
4108 --------------------
4110 function Expr_Rep_Value
(N
: Node_Id
) return Uint
is
4111 Kind
: constant Node_Kind
:= Nkind
(N
);
4115 if Is_Entity_Name
(N
) then
4118 -- An enumeration literal that was either in the source or created
4119 -- as a result of static evaluation.
4121 if Ekind
(Ent
) = E_Enumeration_Literal
then
4122 return Enumeration_Rep
(Ent
);
4124 -- A user defined static constant
4127 pragma Assert
(Ekind
(Ent
) = E_Constant
);
4128 return Expr_Rep_Value
(Constant_Value
(Ent
));
4131 -- An integer literal that was either in the source or created as a
4132 -- result of static evaluation.
4134 elsif Kind
= N_Integer_Literal
then
4137 -- A real literal for a fixed-point type. This must be the fixed-point
4138 -- case, either the literal is of a fixed-point type, or it is a bound
4139 -- of a fixed-point type, with type universal real. In either case we
4140 -- obtain the desired value from Corresponding_Integer_Value.
4142 elsif Kind
= N_Real_Literal
then
4143 pragma Assert
(Is_Fixed_Point_Type
(Underlying_Type
(Etype
(N
))));
4144 return Corresponding_Integer_Value
(N
);
4146 -- Otherwise must be character literal
4149 pragma Assert
(Kind
= N_Character_Literal
);
4152 -- Since Character literals of type Standard.Character don't have any
4153 -- defining character literals built for them, they do not have their
4154 -- Entity set, so just use their Char code. Otherwise for user-
4155 -- defined character literals use their Pos value as usual which is
4156 -- the same as the Rep value.
4159 return Char_Literal_Value
(N
);
4161 return Enumeration_Rep
(Ent
);
4170 function Expr_Value
(N
: Node_Id
) return Uint
is
4171 Kind
: constant Node_Kind
:= Nkind
(N
);
4172 CV_Ent
: CV_Entry
renames CV_Cache
(Nat
(N
) mod CV_Cache_Size
);
4177 -- If already in cache, then we know it's compile time known and we can
4178 -- return the value that was previously stored in the cache since
4179 -- compile time known values cannot change.
4181 if CV_Ent
.N
= N
then
4185 -- Otherwise proceed to test value
4187 if Is_Entity_Name
(N
) then
4190 -- An enumeration literal that was either in the source or created as
4191 -- a result of static evaluation.
4193 if Ekind
(Ent
) = E_Enumeration_Literal
then
4194 Val
:= Enumeration_Pos
(Ent
);
4196 -- A user defined static constant
4199 pragma Assert
(Ekind
(Ent
) = E_Constant
);
4200 Val
:= Expr_Value
(Constant_Value
(Ent
));
4203 -- An integer literal that was either in the source or created as a
4204 -- result of static evaluation.
4206 elsif Kind
= N_Integer_Literal
then
4209 -- A real literal for a fixed-point type. This must be the fixed-point
4210 -- case, either the literal is of a fixed-point type, or it is a bound
4211 -- of a fixed-point type, with type universal real. In either case we
4212 -- obtain the desired value from Corresponding_Integer_Value.
4214 elsif Kind
= N_Real_Literal
then
4215 pragma Assert
(Is_Fixed_Point_Type
(Underlying_Type
(Etype
(N
))));
4216 Val
:= Corresponding_Integer_Value
(N
);
4218 -- The NULL access value
4220 elsif Kind
= N_Null
then
4221 pragma Assert
(Is_Access_Type
(Underlying_Type
(Etype
(N
))));
4224 -- Otherwise must be character literal
4227 pragma Assert
(Kind
= N_Character_Literal
);
4230 -- Since Character literals of type Standard.Character don't
4231 -- have any defining character literals built for them, they
4232 -- do not have their Entity set, so just use their Char
4233 -- code. Otherwise for user-defined character literals use
4234 -- their Pos value as usual.
4237 Val
:= Char_Literal_Value
(N
);
4239 Val
:= Enumeration_Pos
(Ent
);
4243 -- Come here with Val set to value to be returned, set cache
4254 function Expr_Value_E
(N
: Node_Id
) return Entity_Id
is
4255 Ent
: constant Entity_Id
:= Entity
(N
);
4257 if Ekind
(Ent
) = E_Enumeration_Literal
then
4260 pragma Assert
(Ekind
(Ent
) = E_Constant
);
4261 return Expr_Value_E
(Constant_Value
(Ent
));
4269 function Expr_Value_R
(N
: Node_Id
) return Ureal
is
4270 Kind
: constant Node_Kind
:= Nkind
(N
);
4274 if Kind
= N_Real_Literal
then
4277 elsif Kind
= N_Identifier
or else Kind
= N_Expanded_Name
then
4279 pragma Assert
(Ekind
(Ent
) = E_Constant
);
4280 return Expr_Value_R
(Constant_Value
(Ent
));
4282 elsif Kind
= N_Integer_Literal
then
4283 return UR_From_Uint
(Expr_Value
(N
));
4285 -- Here, we have a node that cannot be interpreted as a compile time
4286 -- constant. That is definitely an error.
4289 raise Program_Error
;
4297 function Expr_Value_S
(N
: Node_Id
) return Node_Id
is
4299 if Nkind
(N
) = N_String_Literal
then
4302 pragma Assert
(Ekind
(Entity
(N
)) = E_Constant
);
4303 return Expr_Value_S
(Constant_Value
(Entity
(N
)));
4307 ----------------------------------
4308 -- Find_Universal_Operator_Type --
4309 ----------------------------------
4311 function Find_Universal_Operator_Type
(N
: Node_Id
) return Entity_Id
is
4312 PN
: constant Node_Id
:= Parent
(N
);
4313 Call
: constant Node_Id
:= Original_Node
(N
);
4314 Is_Int
: constant Boolean := Is_Integer_Type
(Etype
(N
));
4316 Is_Fix
: constant Boolean :=
4317 Nkind
(N
) in N_Binary_Op
4318 and then Nkind
(Right_Opnd
(N
)) /= Nkind
(Left_Opnd
(N
));
4319 -- A mixed-mode operation in this context indicates the presence of
4320 -- fixed-point type in the designated package.
4322 Is_Relational
: constant Boolean := Etype
(N
) = Standard_Boolean
;
4323 -- Case where N is a relational (or membership) operator (else it is an
4326 In_Membership
: constant Boolean :=
4327 Nkind
(PN
) in N_Membership_Test
4329 Nkind
(Right_Opnd
(PN
)) = N_Range
4331 Is_Universal_Numeric_Type
(Etype
(Left_Opnd
(PN
)))
4333 Is_Universal_Numeric_Type
4334 (Etype
(Low_Bound
(Right_Opnd
(PN
))))
4336 Is_Universal_Numeric_Type
4337 (Etype
(High_Bound
(Right_Opnd
(PN
))));
4338 -- Case where N is part of a membership test with a universal range
4342 Typ1
: Entity_Id
:= Empty
;
4345 function Is_Mixed_Mode_Operand
(Op
: Node_Id
) return Boolean;
4346 -- Check whether one operand is a mixed-mode operation that requires the
4347 -- presence of a fixed-point type. Given that all operands are universal
4348 -- and have been constant-folded, retrieve the original function call.
4350 ---------------------------
4351 -- Is_Mixed_Mode_Operand --
4352 ---------------------------
4354 function Is_Mixed_Mode_Operand
(Op
: Node_Id
) return Boolean is
4355 Onod
: constant Node_Id
:= Original_Node
(Op
);
4357 return Nkind
(Onod
) = N_Function_Call
4358 and then Present
(Next_Actual
(First_Actual
(Onod
)))
4359 and then Etype
(First_Actual
(Onod
)) /=
4360 Etype
(Next_Actual
(First_Actual
(Onod
)));
4361 end Is_Mixed_Mode_Operand
;
4363 -- Start of processing for Find_Universal_Operator_Type
4366 if Nkind
(Call
) /= N_Function_Call
4367 or else Nkind
(Name
(Call
)) /= N_Expanded_Name
4371 -- There are several cases where the context does not imply the type of
4373 -- - the universal expression appears in a type conversion;
4374 -- - the expression is a relational operator applied to universal
4376 -- - the expression is a membership test with a universal operand
4377 -- and a range with universal bounds.
4379 elsif Nkind
(Parent
(N
)) = N_Type_Conversion
4380 or else Is_Relational
4381 or else In_Membership
4383 Pack
:= Entity
(Prefix
(Name
(Call
)));
4385 -- If the prefix is a package declared elsewhere, iterate over its
4386 -- visible entities, otherwise iterate over all declarations in the
4387 -- designated scope.
4389 if Ekind
(Pack
) = E_Package
4390 and then not In_Open_Scopes
(Pack
)
4392 Priv_E
:= First_Private_Entity
(Pack
);
4398 E
:= First_Entity
(Pack
);
4399 while Present
(E
) and then E
/= Priv_E
loop
4400 if Is_Numeric_Type
(E
)
4401 and then Nkind
(Parent
(E
)) /= N_Subtype_Declaration
4402 and then Comes_From_Source
(E
)
4403 and then Is_Integer_Type
(E
) = Is_Int
4404 and then (Nkind
(N
) in N_Unary_Op
4405 or else Is_Relational
4406 or else Is_Fixed_Point_Type
(E
) = Is_Fix
)
4411 -- Before emitting an error, check for the presence of a
4412 -- mixed-mode operation that specifies a fixed point type.
4416 (Is_Mixed_Mode_Operand
(Left_Opnd
(N
))
4417 or else Is_Mixed_Mode_Operand
(Right_Opnd
(N
)))
4418 and then Is_Fixed_Point_Type
(E
) /= Is_Fixed_Point_Type
(Typ1
)
4421 if Is_Fixed_Point_Type
(E
) then
4426 -- More than one type of the proper class declared in P
4428 Error_Msg_N
("ambiguous operation", N
);
4429 Error_Msg_Sloc
:= Sloc
(Typ1
);
4430 Error_Msg_N
("\possible interpretation (inherited)#", N
);
4431 Error_Msg_Sloc
:= Sloc
(E
);
4432 Error_Msg_N
("\possible interpretation (inherited)#", N
);
4442 end Find_Universal_Operator_Type
;
4444 --------------------------
4445 -- Flag_Non_Static_Expr --
4446 --------------------------
4448 procedure Flag_Non_Static_Expr
(Msg
: String; Expr
: Node_Id
) is
4450 if Error_Posted
(Expr
) and then not All_Errors_Mode
then
4453 Error_Msg_F
(Msg
, Expr
);
4454 Why_Not_Static
(Expr
);
4456 end Flag_Non_Static_Expr
;
4462 procedure Fold_Str
(N
: Node_Id
; Val
: String_Id
; Static
: Boolean) is
4463 Loc
: constant Source_Ptr
:= Sloc
(N
);
4464 Typ
: constant Entity_Id
:= Etype
(N
);
4467 if Raises_Constraint_Error
(N
) then
4468 Set_Is_Static_Expression
(N
, Static
);
4472 Rewrite
(N
, Make_String_Literal
(Loc
, Strval
=> Val
));
4474 -- We now have the literal with the right value, both the actual type
4475 -- and the expected type of this literal are taken from the expression
4476 -- that was evaluated. So now we do the Analyze and Resolve.
4478 -- Note that we have to reset Is_Static_Expression both after the
4479 -- analyze step (because Resolve will evaluate the literal, which
4480 -- will cause semantic errors if it is marked as static), and after
4481 -- the Resolve step (since Resolve in some cases resets this flag).
4484 Set_Is_Static_Expression
(N
, Static
);
4487 Set_Is_Static_Expression
(N
, Static
);
4494 procedure Fold_Uint
(N
: Node_Id
; Val
: Uint
; Static
: Boolean) is
4495 Loc
: constant Source_Ptr
:= Sloc
(N
);
4496 Typ
: Entity_Id
:= Etype
(N
);
4500 if Raises_Constraint_Error
(N
) then
4501 Set_Is_Static_Expression
(N
, Static
);
4505 -- If we are folding a named number, retain the entity in the literal,
4508 if Is_Entity_Name
(N
) and then Ekind
(Entity
(N
)) = E_Named_Integer
then
4514 if Is_Private_Type
(Typ
) then
4515 Typ
:= Full_View
(Typ
);
4518 -- For a result of type integer, substitute an N_Integer_Literal node
4519 -- for the result of the compile time evaluation of the expression.
4520 -- For ASIS use, set a link to the original named number when not in
4521 -- a generic context.
4523 if Is_Integer_Type
(Typ
) then
4524 Rewrite
(N
, Make_Integer_Literal
(Loc
, Val
));
4525 Set_Original_Entity
(N
, Ent
);
4527 -- Otherwise we have an enumeration type, and we substitute either
4528 -- an N_Identifier or N_Character_Literal to represent the enumeration
4529 -- literal corresponding to the given value, which must always be in
4530 -- range, because appropriate tests have already been made for this.
4532 else pragma Assert
(Is_Enumeration_Type
(Typ
));
4533 Rewrite
(N
, Get_Enum_Lit_From_Pos
(Etype
(N
), Val
, Loc
));
4536 -- We now have the literal with the right value, both the actual type
4537 -- and the expected type of this literal are taken from the expression
4538 -- that was evaluated. So now we do the Analyze and Resolve.
4540 -- Note that we have to reset Is_Static_Expression both after the
4541 -- analyze step (because Resolve will evaluate the literal, which
4542 -- will cause semantic errors if it is marked as static), and after
4543 -- the Resolve step (since Resolve in some cases sets this flag).
4546 Set_Is_Static_Expression
(N
, Static
);
4549 Set_Is_Static_Expression
(N
, Static
);
4556 procedure Fold_Ureal
(N
: Node_Id
; Val
: Ureal
; Static
: Boolean) is
4557 Loc
: constant Source_Ptr
:= Sloc
(N
);
4558 Typ
: constant Entity_Id
:= Etype
(N
);
4562 if Raises_Constraint_Error
(N
) then
4563 Set_Is_Static_Expression
(N
, Static
);
4567 -- If we are folding a named number, retain the entity in the literal,
4570 if Is_Entity_Name
(N
) and then Ekind
(Entity
(N
)) = E_Named_Real
then
4576 Rewrite
(N
, Make_Real_Literal
(Loc
, Realval
=> Val
));
4578 -- Set link to original named number, for ASIS use
4580 Set_Original_Entity
(N
, Ent
);
4582 -- We now have the literal with the right value, both the actual type
4583 -- and the expected type of this literal are taken from the expression
4584 -- that was evaluated. So now we do the Analyze and Resolve.
4586 -- Note that we have to reset Is_Static_Expression both after the
4587 -- analyze step (because Resolve will evaluate the literal, which
4588 -- will cause semantic errors if it is marked as static), and after
4589 -- the Resolve step (since Resolve in some cases sets this flag).
4592 Set_Is_Static_Expression
(N
, Static
);
4595 Set_Is_Static_Expression
(N
, Static
);
4602 function From_Bits
(B
: Bits
; T
: Entity_Id
) return Uint
is
4606 for J
in 0 .. B
'Last loop
4612 if Non_Binary_Modulus
(T
) then
4613 V
:= V
mod Modulus
(T
);
4619 --------------------
4620 -- Get_String_Val --
4621 --------------------
4623 function Get_String_Val
(N
: Node_Id
) return Node_Id
is
4625 if Nkind_In
(N
, N_String_Literal
, N_Character_Literal
) then
4628 pragma Assert
(Is_Entity_Name
(N
));
4629 return Get_String_Val
(Constant_Value
(Entity
(N
)));
4637 procedure Initialize
is
4639 CV_Cache
:= (others => (Node_High_Bound
, Uint_0
));
4642 --------------------
4643 -- In_Subrange_Of --
4644 --------------------
4646 function In_Subrange_Of
4649 Fixed_Int
: Boolean := False) return Boolean
4658 if T1
= T2
or else Is_Subtype_Of
(T1
, T2
) then
4661 -- Never in range if both types are not scalar. Don't know if this can
4662 -- actually happen, but just in case.
4664 elsif not Is_Scalar_Type
(T1
) or else not Is_Scalar_Type
(T2
) then
4667 -- If T1 has infinities but T2 doesn't have infinities, then T1 is
4668 -- definitely not compatible with T2.
4670 elsif Is_Floating_Point_Type
(T1
)
4671 and then Has_Infinities
(T1
)
4672 and then Is_Floating_Point_Type
(T2
)
4673 and then not Has_Infinities
(T2
)
4678 L1
:= Type_Low_Bound
(T1
);
4679 H1
:= Type_High_Bound
(T1
);
4681 L2
:= Type_Low_Bound
(T2
);
4682 H2
:= Type_High_Bound
(T2
);
4684 -- Check bounds to see if comparison possible at compile time
4686 if Compile_Time_Compare
(L1
, L2
, Assume_Valid
=> True) in Compare_GE
4688 Compile_Time_Compare
(H1
, H2
, Assume_Valid
=> True) in Compare_LE
4693 -- If bounds not comparable at compile time, then the bounds of T2
4694 -- must be compile time known or we cannot answer the query.
4696 if not Compile_Time_Known_Value
(L2
)
4697 or else not Compile_Time_Known_Value
(H2
)
4702 -- If the bounds of T1 are know at compile time then use these
4703 -- ones, otherwise use the bounds of the base type (which are of
4704 -- course always static).
4706 if not Compile_Time_Known_Value
(L1
) then
4707 L1
:= Type_Low_Bound
(Base_Type
(T1
));
4710 if not Compile_Time_Known_Value
(H1
) then
4711 H1
:= Type_High_Bound
(Base_Type
(T1
));
4714 -- Fixed point types should be considered as such only if
4715 -- flag Fixed_Int is set to False.
4717 if Is_Floating_Point_Type
(T1
) or else Is_Floating_Point_Type
(T2
)
4718 or else (Is_Fixed_Point_Type
(T1
) and then not Fixed_Int
)
4719 or else (Is_Fixed_Point_Type
(T2
) and then not Fixed_Int
)
4722 Expr_Value_R
(L2
) <= Expr_Value_R
(L1
)
4724 Expr_Value_R
(H2
) >= Expr_Value_R
(H1
);
4728 Expr_Value
(L2
) <= Expr_Value
(L1
)
4730 Expr_Value
(H2
) >= Expr_Value
(H1
);
4735 -- If any exception occurs, it means that we have some bug in the compiler
4736 -- possibly triggered by a previous error, or by some unforeseen peculiar
4737 -- occurrence. However, this is only an optimization attempt, so there is
4738 -- really no point in crashing the compiler. Instead we just decide, too
4739 -- bad, we can't figure out the answer in this case after all.
4744 -- Debug flag K disables this behavior (useful for debugging)
4746 if Debug_Flag_K
then
4757 function Is_In_Range
4760 Assume_Valid
: Boolean := False;
4761 Fixed_Int
: Boolean := False;
4762 Int_Real
: Boolean := False) return Boolean
4766 Test_In_Range
(N
, Typ
, Assume_Valid
, Fixed_Int
, Int_Real
) = In_Range
;
4773 function Is_Null_Range
(Lo
: Node_Id
; Hi
: Node_Id
) return Boolean is
4775 if Compile_Time_Known_Value
(Lo
)
4776 and then Compile_Time_Known_Value
(Hi
)
4779 Typ
: Entity_Id
:= Etype
(Lo
);
4781 -- When called from the frontend, as part of the analysis of
4782 -- potentially static expressions, Typ will be the full view of a
4783 -- type with all the info needed to answer this query. When called
4784 -- from the backend, for example to know whether a range of a loop
4785 -- is null, Typ might be a private type and we need to explicitly
4786 -- switch to its corresponding full view to access the same info.
4788 if Is_Incomplete_Or_Private_Type
(Typ
)
4789 and then Present
(Full_View
(Typ
))
4791 Typ
:= Full_View
(Typ
);
4794 if Is_Discrete_Type
(Typ
) then
4795 return Expr_Value
(Lo
) > Expr_Value
(Hi
);
4796 else pragma Assert
(Is_Real_Type
(Typ
));
4797 return Expr_Value_R
(Lo
) > Expr_Value_R
(Hi
);
4805 -------------------------
4806 -- Is_OK_Static_Choice --
4807 -------------------------
4809 function Is_OK_Static_Choice
(Choice
: Node_Id
) return Boolean is
4811 -- Check various possibilities for choice
4813 -- Note: for membership tests, we test more cases than are possible
4814 -- (in particular subtype indication), but it doesn't matter because
4815 -- it just won't occur (we have already done a syntax check).
4817 if Nkind
(Choice
) = N_Others_Choice
then
4820 elsif Nkind
(Choice
) = N_Range
then
4821 return Is_OK_Static_Range
(Choice
);
4823 elsif Nkind
(Choice
) = N_Subtype_Indication
4824 or else (Is_Entity_Name
(Choice
) and then Is_Type
(Entity
(Choice
)))
4826 return Is_OK_Static_Subtype
(Etype
(Choice
));
4829 return Is_OK_Static_Expression
(Choice
);
4831 end Is_OK_Static_Choice
;
4833 ------------------------------
4834 -- Is_OK_Static_Choice_List --
4835 ------------------------------
4837 function Is_OK_Static_Choice_List
(Choices
: List_Id
) return Boolean is
4841 if not Is_Static_Choice_List
(Choices
) then
4845 Choice
:= First
(Choices
);
4846 while Present
(Choice
) loop
4847 if not Is_OK_Static_Choice
(Choice
) then
4848 Set_Raises_Constraint_Error
(Choice
);
4856 end Is_OK_Static_Choice_List
;
4858 -----------------------------
4859 -- Is_OK_Static_Expression --
4860 -----------------------------
4862 function Is_OK_Static_Expression
(N
: Node_Id
) return Boolean is
4864 return Is_Static_Expression
(N
) and then not Raises_Constraint_Error
(N
);
4865 end Is_OK_Static_Expression
;
4867 ------------------------
4868 -- Is_OK_Static_Range --
4869 ------------------------
4871 -- A static range is a range whose bounds are static expressions, or a
4872 -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)).
4873 -- We have already converted range attribute references, so we get the
4874 -- "or" part of this rule without needing a special test.
4876 function Is_OK_Static_Range
(N
: Node_Id
) return Boolean is
4878 return Is_OK_Static_Expression
(Low_Bound
(N
))
4879 and then Is_OK_Static_Expression
(High_Bound
(N
));
4880 end Is_OK_Static_Range
;
4882 --------------------------
4883 -- Is_OK_Static_Subtype --
4884 --------------------------
4886 -- Determines if Typ is a static subtype as defined in (RM 4.9(26)) where
4887 -- neither bound raises constraint error when evaluated.
4889 function Is_OK_Static_Subtype
(Typ
: Entity_Id
) return Boolean is
4890 Base_T
: constant Entity_Id
:= Base_Type
(Typ
);
4891 Anc_Subt
: Entity_Id
;
4894 -- First a quick check on the non static subtype flag. As described
4895 -- in further detail in Einfo, this flag is not decisive in all cases,
4896 -- but if it is set, then the subtype is definitely non-static.
4898 if Is_Non_Static_Subtype
(Typ
) then
4902 Anc_Subt
:= Ancestor_Subtype
(Typ
);
4904 if Anc_Subt
= Empty
then
4908 if Is_Generic_Type
(Root_Type
(Base_T
))
4909 or else Is_Generic_Actual_Type
(Base_T
)
4913 elsif Has_Dynamic_Predicate_Aspect
(Typ
) then
4918 elsif Is_String_Type
(Typ
) then
4920 Ekind
(Typ
) = E_String_Literal_Subtype
4922 (Is_OK_Static_Subtype
(Component_Type
(Typ
))
4923 and then Is_OK_Static_Subtype
(Etype
(First_Index
(Typ
))));
4927 elsif Is_Scalar_Type
(Typ
) then
4928 if Base_T
= Typ
then
4932 -- Scalar_Range (Typ) might be an N_Subtype_Indication, so use
4933 -- Get_Type_{Low,High}_Bound.
4935 return Is_OK_Static_Subtype
(Anc_Subt
)
4936 and then Is_OK_Static_Expression
(Type_Low_Bound
(Typ
))
4937 and then Is_OK_Static_Expression
(Type_High_Bound
(Typ
));
4940 -- Types other than string and scalar types are never static
4945 end Is_OK_Static_Subtype
;
4947 ---------------------
4948 -- Is_Out_Of_Range --
4949 ---------------------
4951 function Is_Out_Of_Range
4954 Assume_Valid
: Boolean := False;
4955 Fixed_Int
: Boolean := False;
4956 Int_Real
: Boolean := False) return Boolean
4959 return Test_In_Range
(N
, Typ
, Assume_Valid
, Fixed_Int
, Int_Real
) =
4961 end Is_Out_Of_Range
;
4963 ----------------------
4964 -- Is_Static_Choice --
4965 ----------------------
4967 function Is_Static_Choice
(Choice
: Node_Id
) return Boolean is
4969 -- Check various possibilities for choice
4971 -- Note: for membership tests, we test more cases than are possible
4972 -- (in particular subtype indication), but it doesn't matter because
4973 -- it just won't occur (we have already done a syntax check).
4975 if Nkind
(Choice
) = N_Others_Choice
then
4978 elsif Nkind
(Choice
) = N_Range
then
4979 return Is_Static_Range
(Choice
);
4981 elsif Nkind
(Choice
) = N_Subtype_Indication
4982 or else (Is_Entity_Name
(Choice
) and then Is_Type
(Entity
(Choice
)))
4984 return Is_Static_Subtype
(Etype
(Choice
));
4987 return Is_Static_Expression
(Choice
);
4989 end Is_Static_Choice
;
4991 ---------------------------
4992 -- Is_Static_Choice_List --
4993 ---------------------------
4995 function Is_Static_Choice_List
(Choices
: List_Id
) return Boolean is
4999 Choice
:= First
(Choices
);
5000 while Present
(Choice
) loop
5001 if not Is_Static_Choice
(Choice
) then
5009 end Is_Static_Choice_List
;
5011 ---------------------
5012 -- Is_Static_Range --
5013 ---------------------
5015 -- A static range is a range whose bounds are static expressions, or a
5016 -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)).
5017 -- We have already converted range attribute references, so we get the
5018 -- "or" part of this rule without needing a special test.
5020 function Is_Static_Range
(N
: Node_Id
) return Boolean is
5022 return Is_Static_Expression
(Low_Bound
(N
))
5024 Is_Static_Expression
(High_Bound
(N
));
5025 end Is_Static_Range
;
5027 -----------------------
5028 -- Is_Static_Subtype --
5029 -----------------------
5031 -- Determines if Typ is a static subtype as defined in (RM 4.9(26))
5033 function Is_Static_Subtype
(Typ
: Entity_Id
) return Boolean is
5034 Base_T
: constant Entity_Id
:= Base_Type
(Typ
);
5035 Anc_Subt
: Entity_Id
;
5038 -- First a quick check on the non static subtype flag. As described
5039 -- in further detail in Einfo, this flag is not decisive in all cases,
5040 -- but if it is set, then the subtype is definitely non-static.
5042 if Is_Non_Static_Subtype
(Typ
) then
5046 Anc_Subt
:= Ancestor_Subtype
(Typ
);
5048 if Anc_Subt
= Empty
then
5052 if Is_Generic_Type
(Root_Type
(Base_T
))
5053 or else Is_Generic_Actual_Type
(Base_T
)
5057 -- If there is a dynamic predicate for the type (declared or inherited)
5058 -- the expression is not static.
5060 elsif Has_Dynamic_Predicate_Aspect
(Typ
)
5061 or else (Is_Derived_Type
(Typ
)
5062 and then Has_Aspect
(Typ
, Aspect_Dynamic_Predicate
))
5068 elsif Is_String_Type
(Typ
) then
5070 Ekind
(Typ
) = E_String_Literal_Subtype
5071 or else (Is_Static_Subtype
(Component_Type
(Typ
))
5072 and then Is_Static_Subtype
(Etype
(First_Index
(Typ
))));
5076 elsif Is_Scalar_Type
(Typ
) then
5077 if Base_T
= Typ
then
5081 return Is_Static_Subtype
(Anc_Subt
)
5082 and then Is_Static_Expression
(Type_Low_Bound
(Typ
))
5083 and then Is_Static_Expression
(Type_High_Bound
(Typ
));
5086 -- Types other than string and scalar types are never static
5091 end Is_Static_Subtype
;
5093 -------------------------------
5094 -- Is_Statically_Unevaluated --
5095 -------------------------------
5097 function Is_Statically_Unevaluated
(Expr
: Node_Id
) return Boolean is
5098 function Check_Case_Expr_Alternative
5099 (CEA
: Node_Id
) return Match_Result
;
5100 -- We have a message emanating from the Expression of a case expression
5101 -- alternative. We examine this alternative, as follows:
5103 -- If the selecting expression of the parent case is non-static, or
5104 -- if any of the discrete choices of the given case alternative are
5105 -- non-static or raise Constraint_Error, return Non_Static.
5107 -- Otherwise check if the selecting expression matches any of the given
5108 -- discrete choices. If so, the alternative is executed and we return
5109 -- Match, otherwise, the alternative can never be executed, and so we
5112 ---------------------------------
5113 -- Check_Case_Expr_Alternative --
5114 ---------------------------------
5116 function Check_Case_Expr_Alternative
5117 (CEA
: Node_Id
) return Match_Result
5119 Case_Exp
: constant Node_Id
:= Parent
(CEA
);
5124 pragma Assert
(Nkind
(Case_Exp
) = N_Case_Expression
);
5126 -- Check that selecting expression is static
5128 if not Is_OK_Static_Expression
(Expression
(Case_Exp
)) then
5132 if not Is_OK_Static_Choice_List
(Discrete_Choices
(CEA
)) then
5136 -- All choices are now known to be static. Now see if alternative
5137 -- matches one of the choices.
5139 Choice
:= First
(Discrete_Choices
(CEA
));
5140 while Present
(Choice
) loop
5142 -- Check various possibilities for choice, returning Match if we
5143 -- find the selecting value matches any of the choices. Note that
5144 -- we know we are the last choice, so we don't have to keep going.
5146 if Nkind
(Choice
) = N_Others_Choice
then
5148 -- Others choice is a bit annoying, it matches if none of the
5149 -- previous alternatives matches (note that we know we are the
5150 -- last alternative in this case, so we can just go backwards
5151 -- from us to see if any previous one matches).
5153 Prev_CEA
:= Prev
(CEA
);
5154 while Present
(Prev_CEA
) loop
5155 if Check_Case_Expr_Alternative
(Prev_CEA
) = Match
then
5164 -- Else we have a normal static choice
5166 elsif Choice_Matches
(Expression
(Case_Exp
), Choice
) = Match
then
5170 -- If we fall through, it means that the discrete choice did not
5171 -- match the selecting expression, so continue.
5176 -- If we get through that loop then all choices were static, and none
5177 -- of them matched the selecting expression. So return No_Match.
5180 end Check_Case_Expr_Alternative
;
5188 -- Start of processing for Is_Statically_Unevaluated
5191 -- The (32.x) references here are from RM section 4.9
5193 -- (32.1) An expression is statically unevaluated if it is part of ...
5195 -- This means we have to climb the tree looking for one of the cases
5202 -- (32.2) The right operand of a static short-circuit control form
5203 -- whose value is determined by its left operand.
5205 -- AND THEN with False as left operand
5207 if Nkind
(P
) = N_And_Then
5208 and then Compile_Time_Known_Value
(Left_Opnd
(P
))
5209 and then Is_False
(Expr_Value
(Left_Opnd
(P
)))
5213 -- OR ELSE with True as left operand
5215 elsif Nkind
(P
) = N_Or_Else
5216 and then Compile_Time_Known_Value
(Left_Opnd
(P
))
5217 and then Is_True
(Expr_Value
(Left_Opnd
(P
)))
5221 -- (32.3) A dependent_expression of an if_expression whose associated
5222 -- condition is static and equals False.
5224 elsif Nkind
(P
) = N_If_Expression
then
5226 Cond
: constant Node_Id
:= First
(Expressions
(P
));
5227 Texp
: constant Node_Id
:= Next
(Cond
);
5228 Fexp
: constant Node_Id
:= Next
(Texp
);
5231 if Compile_Time_Known_Value
(Cond
) then
5233 -- Condition is True and we are in the right operand
5235 if Is_True
(Expr_Value
(Cond
)) and then OldP
= Fexp
then
5238 -- Condition is False and we are in the left operand
5240 elsif Is_False
(Expr_Value
(Cond
)) and then OldP
= Texp
then
5246 -- (32.4) A condition or dependent_expression of an if_expression
5247 -- where the condition corresponding to at least one preceding
5248 -- dependent_expression of the if_expression is static and equals
5251 -- This refers to cases like
5253 -- (if True then 1 elsif 1/0=2 then 2 else 3)
5255 -- But we expand elsif's out anyway, so the above looks like:
5257 -- (if True then 1 else (if 1/0=2 then 2 else 3))
5259 -- So for us this is caught by the above check for the 32.3 case.
5261 -- (32.5) A dependent_expression of a case_expression whose
5262 -- selecting_expression is static and whose value is not covered
5263 -- by the corresponding discrete_choice_list.
5265 elsif Nkind
(P
) = N_Case_Expression_Alternative
then
5267 -- First, we have to be in the expression to suppress messages.
5268 -- If we are within one of the choices, we want the message.
5270 if OldP
= Expression
(P
) then
5272 -- Statically unevaluated if alternative does not match
5274 if Check_Case_Expr_Alternative
(P
) = No_Match
then
5279 -- (32.6) A choice_expression (or a simple_expression of a range
5280 -- that occurs as a membership_choice of a membership_choice_list)
5281 -- of a static membership test that is preceded in the enclosing
5282 -- membership_choice_list by another item whose individual
5283 -- membership test (see (RM 4.5.2)) statically yields True.
5285 elsif Nkind
(P
) in N_Membership_Test
then
5287 -- Only possibly unevaluated if simple expression is static
5289 if not Is_OK_Static_Expression
(Left_Opnd
(P
)) then
5292 -- All members of the choice list must be static
5294 elsif (Present
(Right_Opnd
(P
))
5295 and then not Is_OK_Static_Choice
(Right_Opnd
(P
)))
5296 or else (Present
(Alternatives
(P
))
5298 not Is_OK_Static_Choice_List
(Alternatives
(P
)))
5302 -- If expression is the one and only alternative, then it is
5303 -- definitely not statically unevaluated, so we only have to
5304 -- test the case where there are alternatives present.
5306 elsif Present
(Alternatives
(P
)) then
5308 -- Look for previous matching Choice
5310 Choice
:= First
(Alternatives
(P
));
5311 while Present
(Choice
) loop
5313 -- If we reached us and no previous choices matched, this
5314 -- is not the case where we are statically unevaluated.
5316 exit when OldP
= Choice
;
5318 -- If a previous choice matches, then that is the case where
5319 -- we know our choice is statically unevaluated.
5321 if Choice_Matches
(Left_Opnd
(P
), Choice
) = Match
then
5328 -- If we fall through the loop, we were not one of the choices,
5329 -- we must have been the expression, so that is not covered by
5330 -- this rule, and we keep going.
5336 -- OK, not statically unevaluated at this level, see if we should
5337 -- keep climbing to look for a higher level reason.
5339 -- Special case for component association in aggregates, where
5340 -- we want to keep climbing up to the parent aggregate.
5342 if Nkind
(P
) = N_Component_Association
5343 and then Nkind
(Parent
(P
)) = N_Aggregate
5347 -- All done if not still within subexpression
5350 exit when Nkind
(P
) not in N_Subexpr
;
5354 -- If we fall through the loop, not one of the cases covered!
5357 end Is_Statically_Unevaluated
;
5359 --------------------
5360 -- Not_Null_Range --
5361 --------------------
5363 function Not_Null_Range
(Lo
: Node_Id
; Hi
: Node_Id
) return Boolean is
5365 if Compile_Time_Known_Value
(Lo
)
5366 and then Compile_Time_Known_Value
(Hi
)
5369 Typ
: Entity_Id
:= Etype
(Lo
);
5371 -- When called from the frontend, as part of the analysis of
5372 -- potentially static expressions, Typ will be the full view of a
5373 -- type with all the info needed to answer this query. When called
5374 -- from the backend, for example to know whether a range of a loop
5375 -- is null, Typ might be a private type and we need to explicitly
5376 -- switch to its corresponding full view to access the same info.
5378 if Is_Incomplete_Or_Private_Type
(Typ
)
5379 and then Present
(Full_View
(Typ
))
5381 Typ
:= Full_View
(Typ
);
5384 if Is_Discrete_Type
(Typ
) then
5385 return Expr_Value
(Lo
) <= Expr_Value
(Hi
);
5386 else pragma Assert
(Is_Real_Type
(Typ
));
5387 return Expr_Value_R
(Lo
) <= Expr_Value_R
(Hi
);
5400 function OK_Bits
(N
: Node_Id
; Bits
: Uint
) return Boolean is
5402 -- We allow a maximum of 500,000 bits which seems a reasonable limit
5404 if Bits
< 500_000
then
5407 -- Error if this maximum is exceeded
5410 Error_Msg_N
("static value too large, capacity exceeded", N
);
5419 procedure Out_Of_Range
(N
: Node_Id
) is
5421 -- If we have the static expression case, then this is an illegality
5422 -- in Ada 95 mode, except that in an instance, we never generate an
5423 -- error (if the error is legitimate, it was already diagnosed in the
5426 if Is_Static_Expression
(N
)
5427 and then not In_Instance
5428 and then not In_Inlined_Body
5429 and then Ada_Version
>= Ada_95
5431 -- No message if we are statically unevaluated
5433 if Is_Statically_Unevaluated
(N
) then
5436 -- The expression to compute the length of a packed array is attached
5437 -- to the array type itself, and deserves a separate message.
5439 elsif Nkind
(Parent
(N
)) = N_Defining_Identifier
5440 and then Is_Array_Type
(Parent
(N
))
5441 and then Present
(Packed_Array_Impl_Type
(Parent
(N
)))
5442 and then Present
(First_Rep_Item
(Parent
(N
)))
5445 ("length of packed array must not exceed Integer''Last",
5446 First_Rep_Item
(Parent
(N
)));
5447 Rewrite
(N
, Make_Integer_Literal
(Sloc
(N
), Uint_1
));
5449 -- All cases except the special array case.
5450 -- No message if we are dealing with System.Priority values in
5451 -- CodePeer mode where the target runtime may have more priorities.
5453 elsif not CodePeer_Mode
or else Etype
(N
) /= RTE
(RE_Priority
) then
5454 Apply_Compile_Time_Constraint_Error
5455 (N
, "value not in range of}", CE_Range_Check_Failed
);
5458 -- Here we generate a warning for the Ada 83 case, or when we are in an
5459 -- instance, or when we have a non-static expression case.
5462 Apply_Compile_Time_Constraint_Error
5463 (N
, "value not in range of}??", CE_Range_Check_Failed
);
5467 ----------------------
5468 -- Predicates_Match --
5469 ----------------------
5471 function Predicates_Match
(T1
, T2
: Entity_Id
) return Boolean is
5476 if Ada_Version
< Ada_2012
then
5479 -- Both types must have predicates or lack them
5481 elsif Has_Predicates
(T1
) /= Has_Predicates
(T2
) then
5484 -- Check matching predicates
5489 (T1
, Name_Static_Predicate
, Check_Parents
=> False);
5492 (T2
, Name_Static_Predicate
, Check_Parents
=> False);
5494 -- Subtypes statically match if the predicate comes from the
5495 -- same declaration, which can only happen if one is a subtype
5496 -- of the other and has no explicit predicate.
5498 -- Suppress warnings on order of actuals, which is otherwise
5499 -- triggered by one of the two calls below.
5501 pragma Warnings
(Off
);
5502 return Pred1
= Pred2
5503 or else (No
(Pred1
) and then Is_Subtype_Of
(T1
, T2
))
5504 or else (No
(Pred2
) and then Is_Subtype_Of
(T2
, T1
));
5505 pragma Warnings
(On
);
5507 end Predicates_Match
;
5509 ---------------------------------------------
5510 -- Real_Or_String_Static_Predicate_Matches --
5511 ---------------------------------------------
5513 function Real_Or_String_Static_Predicate_Matches
5515 Typ
: Entity_Id
) return Boolean
5517 Expr
: constant Node_Id
:= Static_Real_Or_String_Predicate
(Typ
);
5518 -- The predicate expression from the type
5520 Pfun
: constant Entity_Id
:= Predicate_Function
(Typ
);
5521 -- The entity for the predicate function
5523 Ent_Name
: constant Name_Id
:= Chars
(First_Formal
(Pfun
));
5524 -- The name of the formal of the predicate function. Occurrences of the
5525 -- type name in Expr have been rewritten as references to this formal,
5526 -- and it has a unique name, so we can identify references by this name.
5529 -- Copy of the predicate function tree
5531 function Process
(N
: Node_Id
) return Traverse_Result
;
5532 -- Function used to process nodes during the traversal in which we will
5533 -- find occurrences of the entity name, and replace such occurrences
5534 -- by a real literal with the value to be tested.
5536 procedure Traverse
is new Traverse_Proc
(Process
);
5537 -- The actual traversal procedure
5543 function Process
(N
: Node_Id
) return Traverse_Result
is
5545 if Nkind
(N
) = N_Identifier
and then Chars
(N
) = Ent_Name
then
5547 Nod
: constant Node_Id
:= New_Copy
(Val
);
5549 Set_Sloc
(Nod
, Sloc
(N
));
5554 -- The predicate function may contain string-comparison operations
5555 -- that have been converted into calls to run-time array-comparison
5556 -- routines. To evaluate the predicate statically, we recover the
5557 -- original comparison operation and replace the occurrence of the
5558 -- formal by the static string value. The actuals of the generated
5559 -- call are of the form X'Address.
5561 elsif Nkind
(N
) in N_Op_Compare
5562 and then Nkind
(Left_Opnd
(N
)) = N_Function_Call
5565 C
: constant Node_Id
:= Left_Opnd
(N
);
5566 F
: constant Node_Id
:= First
(Parameter_Associations
(C
));
5567 L
: constant Node_Id
:= Prefix
(F
);
5568 R
: constant Node_Id
:= Prefix
(Next
(F
));
5571 -- If an operand is an entity name, it is the formal of the
5572 -- predicate function, so replace it with the string value.
5573 -- It may be either operand in the call. The other operand
5574 -- is a static string from the original predicate.
5576 if Is_Entity_Name
(L
) then
5577 Rewrite
(Left_Opnd
(N
), New_Copy
(Val
));
5578 Rewrite
(Right_Opnd
(N
), New_Copy
(R
));
5581 Rewrite
(Left_Opnd
(N
), New_Copy
(L
));
5582 Rewrite
(Right_Opnd
(N
), New_Copy
(Val
));
5593 -- Start of processing for Real_Or_String_Static_Predicate_Matches
5596 -- First deal with special case of inherited predicate, where the
5597 -- predicate expression looks like:
5599 -- xxPredicate (typ (Ent)) and then Expr
5601 -- where Expr is the predicate expression for this level, and the
5602 -- left operand is the call to evaluate the inherited predicate.
5604 if Nkind
(Expr
) = N_And_Then
5605 and then Nkind
(Left_Opnd
(Expr
)) = N_Function_Call
5606 and then Is_Predicate_Function
(Entity
(Name
(Left_Opnd
(Expr
))))
5608 -- OK we have the inherited case, so make a call to evaluate the
5609 -- inherited predicate. If that fails, so do we!
5612 Real_Or_String_Static_Predicate_Matches
5614 Typ
=> Etype
(First_Formal
(Entity
(Name
(Left_Opnd
(Expr
))))))
5619 -- Use the right operand for the continued processing
5621 Copy
:= Copy_Separate_Tree
(Right_Opnd
(Expr
));
5623 -- Case where call to predicate function appears on its own (this means
5624 -- that the predicate at this level is just inherited from the parent).
5626 elsif Nkind
(Expr
) = N_Function_Call
then
5628 Typ
: constant Entity_Id
:=
5629 Etype
(First_Formal
(Entity
(Name
(Expr
))));
5632 -- If the inherited predicate is dynamic, just ignore it. We can't
5633 -- go trying to evaluate a dynamic predicate as a static one!
5635 if Has_Dynamic_Predicate_Aspect
(Typ
) then
5638 -- Otherwise inherited predicate is static, check for match
5641 return Real_Or_String_Static_Predicate_Matches
(Val
, Typ
);
5645 -- If not just an inherited predicate, copy whole expression
5648 Copy
:= Copy_Separate_Tree
(Expr
);
5651 -- Now we replace occurrences of the entity by the value
5655 -- And analyze the resulting static expression to see if it is True
5657 Analyze_And_Resolve
(Copy
, Standard_Boolean
);
5658 return Is_True
(Expr_Value
(Copy
));
5659 end Real_Or_String_Static_Predicate_Matches
;
5661 -------------------------
5662 -- Rewrite_In_Raise_CE --
5663 -------------------------
5665 procedure Rewrite_In_Raise_CE
(N
: Node_Id
; Exp
: Node_Id
) is
5666 Typ
: constant Entity_Id
:= Etype
(N
);
5667 Stat
: constant Boolean := Is_Static_Expression
(N
);
5670 -- If we want to raise CE in the condition of a N_Raise_CE node, we
5671 -- can just clear the condition if the reason is appropriate. We do
5672 -- not do this operation if the parent has a reason other than range
5673 -- check failed, because otherwise we would change the reason.
5675 if Present
(Parent
(N
))
5676 and then Nkind
(Parent
(N
)) = N_Raise_Constraint_Error
5677 and then Reason
(Parent
(N
)) =
5678 UI_From_Int
(RT_Exception_Code
'Pos (CE_Range_Check_Failed
))
5680 Set_Condition
(Parent
(N
), Empty
);
5682 -- Else build an explicit N_Raise_CE
5686 Make_Raise_Constraint_Error
(Sloc
(Exp
),
5687 Reason
=> CE_Range_Check_Failed
));
5688 Set_Raises_Constraint_Error
(N
);
5692 -- Set proper flags in result
5694 Set_Raises_Constraint_Error
(N
, True);
5695 Set_Is_Static_Expression
(N
, Stat
);
5696 end Rewrite_In_Raise_CE
;
5698 ---------------------
5699 -- String_Type_Len --
5700 ---------------------
5702 function String_Type_Len
(Stype
: Entity_Id
) return Uint
is
5703 NT
: constant Entity_Id
:= Etype
(First_Index
(Stype
));
5707 if Is_OK_Static_Subtype
(NT
) then
5710 T
:= Base_Type
(NT
);
5713 return Expr_Value
(Type_High_Bound
(T
)) -
5714 Expr_Value
(Type_Low_Bound
(T
)) + 1;
5715 end String_Type_Len
;
5717 ------------------------------------
5718 -- Subtypes_Statically_Compatible --
5719 ------------------------------------
5721 function Subtypes_Statically_Compatible
5724 Formal_Derived_Matching
: Boolean := False) return Boolean
5729 if Is_Scalar_Type
(T1
) then
5731 -- Definitely compatible if we match
5733 if Subtypes_Statically_Match
(T1
, T2
) then
5736 -- If either subtype is nonstatic then they're not compatible
5738 elsif not Is_OK_Static_Subtype
(T1
)
5740 not Is_OK_Static_Subtype
(T2
)
5744 -- Base types must match, but we don't check that (should we???) but
5745 -- we do at least check that both types are real, or both types are
5748 elsif Is_Real_Type
(T1
) /= Is_Real_Type
(T2
) then
5751 -- Here we check the bounds
5755 LB1
: constant Node_Id
:= Type_Low_Bound
(T1
);
5756 HB1
: constant Node_Id
:= Type_High_Bound
(T1
);
5757 LB2
: constant Node_Id
:= Type_Low_Bound
(T2
);
5758 HB2
: constant Node_Id
:= Type_High_Bound
(T2
);
5761 if Is_Real_Type
(T1
) then
5763 Expr_Value_R
(LB1
) > Expr_Value_R
(HB1
)
5765 (Expr_Value_R
(LB2
) <= Expr_Value_R
(LB1
)
5766 and then Expr_Value_R
(HB1
) <= Expr_Value_R
(HB2
));
5770 Expr_Value
(LB1
) > Expr_Value
(HB1
)
5772 (Expr_Value
(LB2
) <= Expr_Value
(LB1
)
5773 and then Expr_Value
(HB1
) <= Expr_Value
(HB2
));
5780 elsif Is_Access_Type
(T1
) then
5782 (not Is_Constrained
(T2
)
5783 or else Subtypes_Statically_Match
5784 (Designated_Type
(T1
), Designated_Type
(T2
)))
5785 and then not (Can_Never_Be_Null
(T2
)
5786 and then not Can_Never_Be_Null
(T1
));
5792 (Is_Composite_Type
(T1
) and then not Is_Constrained
(T2
))
5793 or else Subtypes_Statically_Match
5794 (T1
, T2
, Formal_Derived_Matching
);
5796 end Subtypes_Statically_Compatible
;
5798 -------------------------------
5799 -- Subtypes_Statically_Match --
5800 -------------------------------
5802 -- Subtypes statically match if they have statically matching constraints
5803 -- (RM 4.9.1(2)). Constraints statically match if there are none, or if
5804 -- they are the same identical constraint, or if they are static and the
5805 -- values match (RM 4.9.1(1)).
5807 -- In addition, in GNAT, the object size (Esize) values of the types must
5808 -- match if they are set (unless checking an actual for a formal derived
5809 -- type). The use of 'Object_Size can cause this to be false even if the
5810 -- types would otherwise match in the RM sense.
5812 function Subtypes_Statically_Match
5815 Formal_Derived_Matching
: Boolean := False) return Boolean
5818 -- A type always statically matches itself
5823 -- No match if sizes different (from use of 'Object_Size). This test
5824 -- is excluded if Formal_Derived_Matching is True, as the base types
5825 -- can be different in that case and typically have different sizes.
5826 -- ??? Frontend_Layout_On_Target used to set Esizes but this is no
5827 -- longer the case, consider removing the last test below.
5829 elsif not Formal_Derived_Matching
5830 and then Known_Static_Esize
(T1
)
5831 and then Known_Static_Esize
(T2
)
5832 and then Esize
(T1
) /= Esize
(T2
)
5836 -- No match if predicates do not match
5838 elsif not Predicates_Match
(T1
, T2
) then
5843 elsif Is_Scalar_Type
(T1
) then
5845 -- Base types must be the same
5847 if Base_Type
(T1
) /= Base_Type
(T2
) then
5851 -- A constrained numeric subtype never matches an unconstrained
5852 -- subtype, i.e. both types must be constrained or unconstrained.
5854 -- To understand the requirement for this test, see RM 4.9.1(1).
5855 -- As is made clear in RM 3.5.4(11), type Integer, for example is
5856 -- a constrained subtype with constraint bounds matching the bounds
5857 -- of its corresponding unconstrained base type. In this situation,
5858 -- Integer and Integer'Base do not statically match, even though
5859 -- they have the same bounds.
5861 -- We only apply this test to types in Standard and types that appear
5862 -- in user programs. That way, we do not have to be too careful about
5863 -- setting Is_Constrained right for Itypes.
5865 if Is_Numeric_Type
(T1
)
5866 and then (Is_Constrained
(T1
) /= Is_Constrained
(T2
))
5867 and then (Scope
(T1
) = Standard_Standard
5868 or else Comes_From_Source
(T1
))
5869 and then (Scope
(T2
) = Standard_Standard
5870 or else Comes_From_Source
(T2
))
5874 -- A generic scalar type does not statically match its base type
5875 -- (AI-311). In this case we make sure that the formals, which are
5876 -- first subtypes of their bases, are constrained.
5878 elsif Is_Generic_Type
(T1
)
5879 and then Is_Generic_Type
(T2
)
5880 and then (Is_Constrained
(T1
) /= Is_Constrained
(T2
))
5885 -- If there was an error in either range, then just assume the types
5886 -- statically match to avoid further junk errors.
5888 if No
(Scalar_Range
(T1
)) or else No
(Scalar_Range
(T2
))
5889 or else Error_Posted
(Scalar_Range
(T1
))
5890 or else Error_Posted
(Scalar_Range
(T2
))
5895 -- Otherwise both types have bounds that can be compared
5898 LB1
: constant Node_Id
:= Type_Low_Bound
(T1
);
5899 HB1
: constant Node_Id
:= Type_High_Bound
(T1
);
5900 LB2
: constant Node_Id
:= Type_Low_Bound
(T2
);
5901 HB2
: constant Node_Id
:= Type_High_Bound
(T2
);
5904 -- If the bounds are the same tree node, then match (common case)
5906 if LB1
= LB2
and then HB1
= HB2
then
5909 -- Otherwise bounds must be static and identical value
5912 if not Is_OK_Static_Subtype
(T1
)
5914 not Is_OK_Static_Subtype
(T2
)
5918 elsif Is_Real_Type
(T1
) then
5920 Expr_Value_R
(LB1
) = Expr_Value_R
(LB2
)
5922 Expr_Value_R
(HB1
) = Expr_Value_R
(HB2
);
5926 Expr_Value
(LB1
) = Expr_Value
(LB2
)
5928 Expr_Value
(HB1
) = Expr_Value
(HB2
);
5933 -- Type with discriminants
5935 elsif Has_Discriminants
(T1
) or else Has_Discriminants
(T2
) then
5937 -- Because of view exchanges in multiple instantiations, conformance
5938 -- checking might try to match a partial view of a type with no
5939 -- discriminants with a full view that has defaulted discriminants.
5940 -- In such a case, use the discriminant constraint of the full view,
5941 -- which must exist because we know that the two subtypes have the
5944 if Has_Discriminants
(T1
) /= Has_Discriminants
(T2
) then
5945 -- A generic actual type is declared through a subtype declaration
5946 -- and may have an inconsistent indication of the presence of
5947 -- discriminants, so check the type it renames.
5949 if Is_Generic_Actual_Type
(T1
)
5950 and then not Has_Discriminants
(Etype
(T1
))
5951 and then not Has_Discriminants
(T2
)
5955 elsif In_Instance
then
5956 if Is_Private_Type
(T2
)
5957 and then Present
(Full_View
(T2
))
5958 and then Has_Discriminants
(Full_View
(T2
))
5960 return Subtypes_Statically_Match
(T1
, Full_View
(T2
));
5962 elsif Is_Private_Type
(T1
)
5963 and then Present
(Full_View
(T1
))
5964 and then Has_Discriminants
(Full_View
(T1
))
5966 return Subtypes_Statically_Match
(Full_View
(T1
), T2
);
5977 DL1
: constant Elist_Id
:= Discriminant_Constraint
(T1
);
5978 DL2
: constant Elist_Id
:= Discriminant_Constraint
(T2
);
5986 elsif Is_Constrained
(T1
) /= Is_Constrained
(T2
) then
5990 -- Now loop through the discriminant constraints
5992 -- Note: the guard here seems necessary, since it is possible at
5993 -- least for DL1 to be No_Elist. Not clear this is reasonable ???
5995 if Present
(DL1
) and then Present
(DL2
) then
5996 DA1
:= First_Elmt
(DL1
);
5997 DA2
:= First_Elmt
(DL2
);
5998 while Present
(DA1
) loop
6000 Expr1
: constant Node_Id
:= Node
(DA1
);
6001 Expr2
: constant Node_Id
:= Node
(DA2
);
6004 if not Is_OK_Static_Expression
(Expr1
)
6005 or else not Is_OK_Static_Expression
(Expr2
)
6009 -- If either expression raised a constraint error,
6010 -- consider the expressions as matching, since this
6011 -- helps to prevent cascading errors.
6013 elsif Raises_Constraint_Error
(Expr1
)
6014 or else Raises_Constraint_Error
(Expr2
)
6018 elsif Expr_Value
(Expr1
) /= Expr_Value
(Expr2
) then
6031 -- A definite type does not match an indefinite or classwide type.
6032 -- However, a generic type with unknown discriminants may be
6033 -- instantiated with a type with no discriminants, and conformance
6034 -- checking on an inherited operation may compare the actual with the
6035 -- subtype that renames it in the instance.
6037 elsif Has_Unknown_Discriminants
(T1
) /= Has_Unknown_Discriminants
(T2
)
6040 Is_Generic_Actual_Type
(T1
) or else Is_Generic_Actual_Type
(T2
);
6044 elsif Is_Array_Type
(T1
) then
6046 -- If either subtype is unconstrained then both must be, and if both
6047 -- are unconstrained then no further checking is needed.
6049 if not Is_Constrained
(T1
) or else not Is_Constrained
(T2
) then
6050 return not (Is_Constrained
(T1
) or else Is_Constrained
(T2
));
6053 -- Both subtypes are constrained, so check that the index subtypes
6054 -- statically match.
6057 Index1
: Node_Id
:= First_Index
(T1
);
6058 Index2
: Node_Id
:= First_Index
(T2
);
6061 while Present
(Index1
) loop
6063 Subtypes_Statically_Match
(Etype
(Index1
), Etype
(Index2
))
6068 Next_Index
(Index1
);
6069 Next_Index
(Index2
);
6075 elsif Is_Access_Type
(T1
) then
6076 if Can_Never_Be_Null
(T1
) /= Can_Never_Be_Null
(T2
) then
6079 elsif Ekind_In
(T1
, E_Access_Subprogram_Type
,
6080 E_Anonymous_Access_Subprogram_Type
)
6084 (Designated_Type
(T1
),
6085 Designated_Type
(T2
));
6088 Subtypes_Statically_Match
6089 (Designated_Type
(T1
),
6090 Designated_Type
(T2
))
6091 and then Is_Access_Constant
(T1
) = Is_Access_Constant
(T2
);
6094 -- All other types definitely match
6099 end Subtypes_Statically_Match
;
6105 function Test
(Cond
: Boolean) return Uint
is
6114 ---------------------
6115 -- Test_Comparison --
6116 ---------------------
6118 procedure Test_Comparison
6120 Assume_Valid
: Boolean;
6121 True_Result
: out Boolean;
6122 False_Result
: out Boolean)
6124 Left
: constant Node_Id
:= Left_Opnd
(Op
);
6125 Left_Typ
: constant Entity_Id
:= Etype
(Left
);
6126 Orig_Op
: constant Node_Id
:= Original_Node
(Op
);
6128 procedure Replacement_Warning
(Msg
: String);
6129 -- Emit a warning on a comparison that can be replaced by '='
6131 -------------------------
6132 -- Replacement_Warning --
6133 -------------------------
6135 procedure Replacement_Warning
(Msg
: String) is
6137 if Constant_Condition_Warnings
6138 and then Comes_From_Source
(Orig_Op
)
6139 and then Is_Integer_Type
(Left_Typ
)
6140 and then not Error_Posted
(Op
)
6141 and then not Has_Warnings_Off
(Left_Typ
)
6142 and then not In_Instance
6144 Error_Msg_N
(Msg
, Op
);
6146 end Replacement_Warning
;
6150 Res
: constant Compare_Result
:=
6151 Compile_Time_Compare
(Left
, Right_Opnd
(Op
), Assume_Valid
);
6153 -- Start of processing for Test_Comparison
6156 case N_Op_Compare
(Nkind
(Op
)) is
6158 True_Result
:= Res
= EQ
;
6159 False_Result
:= Res
= LT
or else Res
= GT
or else Res
= NE
;
6162 True_Result
:= Res
in Compare_GE
;
6163 False_Result
:= Res
= LT
;
6165 if Res
= LE
and then Nkind
(Orig_Op
) = N_Op_Ge
then
6167 ("can never be greater than, could replace by ""'=""?c?");
6171 True_Result
:= Res
= GT
;
6172 False_Result
:= Res
in Compare_LE
;
6175 True_Result
:= Res
in Compare_LE
;
6176 False_Result
:= Res
= GT
;
6178 if Res
= GE
and then Nkind
(Orig_Op
) = N_Op_Le
then
6180 ("can never be less than, could replace by ""'=""?c?");
6184 True_Result
:= Res
= LT
;
6185 False_Result
:= Res
in Compare_GE
;
6188 True_Result
:= Res
= NE
or else Res
= GT
or else Res
= LT
;
6189 False_Result
:= Res
= EQ
;
6191 end Test_Comparison
;
6193 ---------------------------------
6194 -- Test_Expression_Is_Foldable --
6195 ---------------------------------
6199 procedure Test_Expression_Is_Foldable
6209 if Debug_Flag_Dot_F
and then In_Extended_Main_Source_Unit
(N
) then
6213 -- If operand is Any_Type, just propagate to result and do not
6214 -- try to fold, this prevents cascaded errors.
6216 if Etype
(Op1
) = Any_Type
then
6217 Set_Etype
(N
, Any_Type
);
6220 -- If operand raises constraint error, then replace node N with the
6221 -- raise constraint error node, and we are obviously not foldable.
6222 -- Note that this replacement inherits the Is_Static_Expression flag
6223 -- from the operand.
6225 elsif Raises_Constraint_Error
(Op1
) then
6226 Rewrite_In_Raise_CE
(N
, Op1
);
6229 -- If the operand is not static, then the result is not static, and
6230 -- all we have to do is to check the operand since it is now known
6231 -- to appear in a non-static context.
6233 elsif not Is_Static_Expression
(Op1
) then
6234 Check_Non_Static_Context
(Op1
);
6235 Fold
:= Compile_Time_Known_Value
(Op1
);
6238 -- An expression of a formal modular type is not foldable because
6239 -- the modulus is unknown.
6241 elsif Is_Modular_Integer_Type
(Etype
(Op1
))
6242 and then Is_Generic_Type
(Etype
(Op1
))
6244 Check_Non_Static_Context
(Op1
);
6247 -- Here we have the case of an operand whose type is OK, which is
6248 -- static, and which does not raise constraint error, we can fold.
6251 Set_Is_Static_Expression
(N
);
6255 end Test_Expression_Is_Foldable
;
6259 procedure Test_Expression_Is_Foldable
6265 CRT_Safe
: Boolean := False)
6267 Rstat
: constant Boolean := Is_Static_Expression
(Op1
)
6269 Is_Static_Expression
(Op2
);
6275 -- Inhibit folding if -gnatd.f flag set
6277 if Debug_Flag_Dot_F
and then In_Extended_Main_Source_Unit
(N
) then
6281 -- If either operand is Any_Type, just propagate to result and
6282 -- do not try to fold, this prevents cascaded errors.
6284 if Etype
(Op1
) = Any_Type
or else Etype
(Op2
) = Any_Type
then
6285 Set_Etype
(N
, Any_Type
);
6288 -- If left operand raises constraint error, then replace node N with the
6289 -- Raise_Constraint_Error node, and we are obviously not foldable.
6290 -- Is_Static_Expression is set from the two operands in the normal way,
6291 -- and we check the right operand if it is in a non-static context.
6293 elsif Raises_Constraint_Error
(Op1
) then
6295 Check_Non_Static_Context
(Op2
);
6298 Rewrite_In_Raise_CE
(N
, Op1
);
6299 Set_Is_Static_Expression
(N
, Rstat
);
6302 -- Similar processing for the case of the right operand. Note that we
6303 -- don't use this routine for the short-circuit case, so we do not have
6304 -- to worry about that special case here.
6306 elsif Raises_Constraint_Error
(Op2
) then
6308 Check_Non_Static_Context
(Op1
);
6311 Rewrite_In_Raise_CE
(N
, Op2
);
6312 Set_Is_Static_Expression
(N
, Rstat
);
6315 -- Exclude expressions of a generic modular type, as above
6317 elsif Is_Modular_Integer_Type
(Etype
(Op1
))
6318 and then Is_Generic_Type
(Etype
(Op1
))
6320 Check_Non_Static_Context
(Op1
);
6323 -- If result is not static, then check non-static contexts on operands
6324 -- since one of them may be static and the other one may not be static.
6326 elsif not Rstat
then
6327 Check_Non_Static_Context
(Op1
);
6328 Check_Non_Static_Context
(Op2
);
6331 Fold
:= CRT_Safe_Compile_Time_Known_Value
(Op1
)
6332 and then CRT_Safe_Compile_Time_Known_Value
(Op2
);
6334 Fold
:= Compile_Time_Known_Value
(Op1
)
6335 and then Compile_Time_Known_Value
(Op2
);
6340 -- Else result is static and foldable. Both operands are static, and
6341 -- neither raises constraint error, so we can definitely fold.
6344 Set_Is_Static_Expression
(N
);
6349 end Test_Expression_Is_Foldable
;
6355 function Test_In_Range
6358 Assume_Valid
: Boolean;
6359 Fixed_Int
: Boolean;
6360 Int_Real
: Boolean) return Range_Membership
6365 pragma Warnings
(Off
, Assume_Valid
);
6366 -- For now Assume_Valid is unreferenced since the current implementation
6367 -- always returns Unknown if N is not a compile time known value, but we
6368 -- keep the parameter to allow for future enhancements in which we try
6369 -- to get the information in the variable case as well.
6372 -- If an error was posted on expression, then return Unknown, we do not
6373 -- want cascaded errors based on some false analysis of a junk node.
6375 if Error_Posted
(N
) then
6378 -- Expression that raises constraint error is an odd case. We certainly
6379 -- do not want to consider it to be in range. It might make sense to
6380 -- consider it always out of range, but this causes incorrect error
6381 -- messages about static expressions out of range. So we just return
6382 -- Unknown, which is always safe.
6384 elsif Raises_Constraint_Error
(N
) then
6387 -- Universal types have no range limits, so always in range
6389 elsif Typ
= Universal_Integer
or else Typ
= Universal_Real
then
6392 -- Never known if not scalar type. Don't know if this can actually
6393 -- happen, but our spec allows it, so we must check.
6395 elsif not Is_Scalar_Type
(Typ
) then
6398 -- Never known if this is a generic type, since the bounds of generic
6399 -- types are junk. Note that if we only checked for static expressions
6400 -- (instead of compile time known values) below, we would not need this
6401 -- check, because values of a generic type can never be static, but they
6402 -- can be known at compile time.
6404 elsif Is_Generic_Type
(Typ
) then
6407 -- Case of a known compile time value, where we can check if it is in
6408 -- the bounds of the given type.
6410 elsif Compile_Time_Known_Value
(N
) then
6419 Lo
:= Type_Low_Bound
(Typ
);
6420 Hi
:= Type_High_Bound
(Typ
);
6422 LB_Known
:= Compile_Time_Known_Value
(Lo
);
6423 HB_Known
:= Compile_Time_Known_Value
(Hi
);
6425 -- Fixed point types should be considered as such only if flag
6426 -- Fixed_Int is set to False.
6428 if Is_Floating_Point_Type
(Typ
)
6429 or else (Is_Fixed_Point_Type
(Typ
) and then not Fixed_Int
)
6432 Valr
:= Expr_Value_R
(N
);
6434 if LB_Known
and HB_Known
then
6435 if Valr
>= Expr_Value_R
(Lo
)
6437 Valr
<= Expr_Value_R
(Hi
)
6441 return Out_Of_Range
;
6444 elsif (LB_Known
and then Valr
< Expr_Value_R
(Lo
))
6446 (HB_Known
and then Valr
> Expr_Value_R
(Hi
))
6448 return Out_Of_Range
;
6455 Val
:= Expr_Value
(N
);
6457 if LB_Known
and HB_Known
then
6458 if Val
>= Expr_Value
(Lo
) and then Val
<= Expr_Value
(Hi
)
6462 return Out_Of_Range
;
6465 elsif (LB_Known
and then Val
< Expr_Value
(Lo
))
6467 (HB_Known
and then Val
> Expr_Value
(Hi
))
6469 return Out_Of_Range
;
6477 -- Here for value not known at compile time. Case of expression subtype
6478 -- is Typ or is a subtype of Typ, and we can assume expression is valid.
6479 -- In this case we know it is in range without knowing its value.
6482 and then (Etype
(N
) = Typ
or else Is_Subtype_Of
(Etype
(N
), Typ
))
6486 -- Another special case. For signed integer types, if the target type
6487 -- has Is_Known_Valid set, and the source type does not have a larger
6488 -- size, then the source value must be in range. We exclude biased
6489 -- types, because they bizarrely can generate out of range values.
6491 elsif Is_Signed_Integer_Type
(Etype
(N
))
6492 and then Is_Known_Valid
(Typ
)
6493 and then Esize
(Etype
(N
)) <= Esize
(Typ
)
6494 and then not Has_Biased_Representation
(Etype
(N
))
6498 -- For all other cases, result is unknown
6509 procedure To_Bits
(U
: Uint
; B
: out Bits
) is
6511 for J
in 0 .. B
'Last loop
6512 B
(J
) := (U
/ (2 ** J
)) mod 2 /= 0;
6516 --------------------
6517 -- Why_Not_Static --
6518 --------------------
6520 procedure Why_Not_Static
(Expr
: Node_Id
) is
6521 N
: constant Node_Id
:= Original_Node
(Expr
);
6522 Typ
: Entity_Id
:= Empty
;
6527 procedure Why_Not_Static_List
(L
: List_Id
);
6528 -- A version that can be called on a list of expressions. Finds all
6529 -- non-static violations in any element of the list.
6531 -------------------------
6532 -- Why_Not_Static_List --
6533 -------------------------
6535 procedure Why_Not_Static_List
(L
: List_Id
) is
6538 if Is_Non_Empty_List
(L
) then
6540 while Present
(N
) loop
6545 end Why_Not_Static_List
;
6547 -- Start of processing for Why_Not_Static
6550 -- Ignore call on error or empty node
6552 if No
(Expr
) or else Nkind
(Expr
) = N_Error
then
6556 -- Preprocessing for sub expressions
6558 if Nkind
(Expr
) in N_Subexpr
then
6560 -- Nothing to do if expression is static
6562 if Is_OK_Static_Expression
(Expr
) then
6566 -- Test for constraint error raised
6568 if Raises_Constraint_Error
(Expr
) then
6570 -- Special case membership to find out which piece to flag
6572 if Nkind
(N
) in N_Membership_Test
then
6573 if Raises_Constraint_Error
(Left_Opnd
(N
)) then
6574 Why_Not_Static
(Left_Opnd
(N
));
6577 elsif Present
(Right_Opnd
(N
))
6578 and then Raises_Constraint_Error
(Right_Opnd
(N
))
6580 Why_Not_Static
(Right_Opnd
(N
));
6584 pragma Assert
(Present
(Alternatives
(N
)));
6586 Alt
:= First
(Alternatives
(N
));
6587 while Present
(Alt
) loop
6588 if Raises_Constraint_Error
(Alt
) then
6589 Why_Not_Static
(Alt
);
6597 -- Special case a range to find out which bound to flag
6599 elsif Nkind
(N
) = N_Range
then
6600 if Raises_Constraint_Error
(Low_Bound
(N
)) then
6601 Why_Not_Static
(Low_Bound
(N
));
6604 elsif Raises_Constraint_Error
(High_Bound
(N
)) then
6605 Why_Not_Static
(High_Bound
(N
));
6609 -- Special case attribute to see which part to flag
6611 elsif Nkind
(N
) = N_Attribute_Reference
then
6612 if Raises_Constraint_Error
(Prefix
(N
)) then
6613 Why_Not_Static
(Prefix
(N
));
6617 if Present
(Expressions
(N
)) then
6618 Exp
:= First
(Expressions
(N
));
6619 while Present
(Exp
) loop
6620 if Raises_Constraint_Error
(Exp
) then
6621 Why_Not_Static
(Exp
);
6629 -- Special case a subtype name
6631 elsif Is_Entity_Name
(Expr
) and then Is_Type
(Entity
(Expr
)) then
6633 ("!& is not a static subtype (RM 4.9(26))", N
, Entity
(Expr
));
6637 -- End of special cases
6640 ("!expression raises exception, cannot be static (RM 4.9(34))",
6645 -- If no type, then something is pretty wrong, so ignore
6647 Typ
:= Etype
(Expr
);
6653 -- Type must be scalar or string type (but allow Bignum, since this
6654 -- is really a scalar type from our point of view in this diagnosis).
6656 if not Is_Scalar_Type
(Typ
)
6657 and then not Is_String_Type
(Typ
)
6658 and then not Is_RTE
(Typ
, RE_Bignum
)
6661 ("!static expression must have scalar or string type " &
6667 -- If we got through those checks, test particular node kind
6673 when N_Expanded_Name
6679 if Is_Named_Number
(E
) then
6682 elsif Ekind
(E
) = E_Constant
then
6684 -- One case we can give a metter message is when we have a
6685 -- string literal created by concatenating an aggregate with
6686 -- an others expression.
6688 Entity_Case
: declare
6689 CV
: constant Node_Id
:= Constant_Value
(E
);
6690 CO
: constant Node_Id
:= Original_Node
(CV
);
6692 function Is_Aggregate
(N
: Node_Id
) return Boolean;
6693 -- See if node N came from an others aggregate, if so
6694 -- return True and set Error_Msg_Sloc to aggregate.
6700 function Is_Aggregate
(N
: Node_Id
) return Boolean is
6702 if Nkind
(Original_Node
(N
)) = N_Aggregate
then
6703 Error_Msg_Sloc
:= Sloc
(Original_Node
(N
));
6706 elsif Is_Entity_Name
(N
)
6707 and then Ekind
(Entity
(N
)) = E_Constant
6709 Nkind
(Original_Node
(Constant_Value
(Entity
(N
)))) =
6713 Sloc
(Original_Node
(Constant_Value
(Entity
(N
))));
6721 -- Start of processing for Entity_Case
6724 if Is_Aggregate
(CV
)
6725 or else (Nkind
(CO
) = N_Op_Concat
6726 and then (Is_Aggregate
(Left_Opnd
(CO
))
6728 Is_Aggregate
(Right_Opnd
(CO
))))
6730 Error_Msg_N
("!aggregate (#) is never static", N
);
6732 elsif No
(CV
) or else not Is_Static_Expression
(CV
) then
6734 ("!& is not a static constant (RM 4.9(5))", N
, E
);
6738 elsif Is_Type
(E
) then
6740 ("!& is not a static subtype (RM 4.9(26))", N
, E
);
6744 ("!& is not static constant or named number "
6745 & "(RM 4.9(5))", N
, E
);
6754 if Nkind
(N
) in N_Op_Shift
then
6756 ("!shift functions are never static (RM 4.9(6,18))", N
);
6758 Why_Not_Static
(Left_Opnd
(N
));
6759 Why_Not_Static
(Right_Opnd
(N
));
6765 Why_Not_Static
(Right_Opnd
(N
));
6767 -- Attribute reference
6769 when N_Attribute_Reference
=>
6770 Why_Not_Static_List
(Expressions
(N
));
6772 E
:= Etype
(Prefix
(N
));
6774 if E
= Standard_Void_Type
then
6778 -- Special case non-scalar'Size since this is a common error
6780 if Attribute_Name
(N
) = Name_Size
then
6782 ("!size attribute is only static for static scalar type "
6783 & "(RM 4.9(7,8))", N
);
6787 elsif Is_Array_Type
(E
) then
6788 if not Nam_In
(Attribute_Name
(N
), Name_First
,
6793 ("!static array attribute must be Length, First, or Last "
6794 & "(RM 4.9(8))", N
);
6796 -- Since we know the expression is not-static (we already
6797 -- tested for this, must mean array is not static).
6801 ("!prefix is non-static array (RM 4.9(8))", Prefix
(N
));
6806 -- Special case generic types, since again this is a common source
6809 elsif Is_Generic_Actual_Type
(E
) or else Is_Generic_Type
(E
) then
6811 ("!attribute of generic type is never static "
6812 & "(RM 4.9(7,8))", N
);
6814 elsif Is_OK_Static_Subtype
(E
) then
6817 elsif Is_Scalar_Type
(E
) then
6819 ("!prefix type for attribute is not static scalar subtype "
6820 & "(RM 4.9(7))", N
);
6824 ("!static attribute must apply to array/scalar type "
6825 & "(RM 4.9(7,8))", N
);
6830 when N_String_Literal
=>
6832 ("!subtype of string literal is non-static (RM 4.9(4))", N
);
6834 -- Explicit dereference
6836 when N_Explicit_Dereference
=>
6838 ("!explicit dereference is never static (RM 4.9)", N
);
6842 when N_Function_Call
=>
6843 Why_Not_Static_List
(Parameter_Associations
(N
));
6845 -- Complain about non-static function call unless we have Bignum
6846 -- which means that the underlying expression is really some
6847 -- scalar arithmetic operation.
6849 if not Is_RTE
(Typ
, RE_Bignum
) then
6850 Error_Msg_N
("!non-static function call (RM 4.9(6,18))", N
);
6853 -- Parameter assocation (test actual parameter)
6855 when N_Parameter_Association
=>
6856 Why_Not_Static
(Explicit_Actual_Parameter
(N
));
6858 -- Indexed component
6860 when N_Indexed_Component
=>
6861 Error_Msg_N
("!indexed component is never static (RM 4.9)", N
);
6865 when N_Procedure_Call_Statement
=>
6866 Error_Msg_N
("!procedure call is never static (RM 4.9)", N
);
6868 -- Qualified expression (test expression)
6870 when N_Qualified_Expression
=>
6871 Why_Not_Static
(Expression
(N
));
6876 | N_Extension_Aggregate
6878 Error_Msg_N
("!an aggregate is never static (RM 4.9)", N
);
6883 Why_Not_Static
(Low_Bound
(N
));
6884 Why_Not_Static
(High_Bound
(N
));
6886 -- Range constraint, test range expression
6888 when N_Range_Constraint
=>
6889 Why_Not_Static
(Range_Expression
(N
));
6891 -- Subtype indication, test constraint
6893 when N_Subtype_Indication
=>
6894 Why_Not_Static
(Constraint
(N
));
6896 -- Selected component
6898 when N_Selected_Component
=>
6899 Error_Msg_N
("!selected component is never static (RM 4.9)", N
);
6904 Error_Msg_N
("!slice is never static (RM 4.9)", N
);
6906 when N_Type_Conversion
=>
6907 Why_Not_Static
(Expression
(N
));
6909 if not Is_Scalar_Type
(Entity
(Subtype_Mark
(N
)))
6910 or else not Is_OK_Static_Subtype
(Entity
(Subtype_Mark
(N
)))
6913 ("!static conversion requires static scalar subtype result "
6914 & "(RM 4.9(9))", N
);
6917 -- Unchecked type conversion
6919 when N_Unchecked_Type_Conversion
=>
6921 ("!unchecked type conversion is never static (RM 4.9)", N
);
6923 -- All other cases, no reason to give