1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree; use Atree;
27 with Checks; use Checks;
28 with Debug; use Debug;
29 with Einfo; use Einfo;
30 with Elists; use Elists;
31 with Errout; use Errout;
32 with Eval_Fat; use Eval_Fat;
33 with Exp_Util; use Exp_Util;
34 with Freeze; use Freeze;
36 with Namet; use Namet;
37 with Nmake; use Nmake;
38 with Nlists; use Nlists;
40 with Par_SCO; use Par_SCO;
41 with Rtsfind; use Rtsfind;
43 with Sem_Aux; use Sem_Aux;
44 with Sem_Cat; use Sem_Cat;
45 with Sem_Ch6; use Sem_Ch6;
46 with Sem_Ch8; use Sem_Ch8;
47 with Sem_Res; use Sem_Res;
48 with Sem_Util; use Sem_Util;
49 with Sem_Type; use Sem_Type;
50 with Sem_Warn; use Sem_Warn;
51 with Sinfo; use Sinfo;
52 with Snames; use Snames;
53 with Stand; use Stand;
54 with Stringt; use Stringt;
55 with Tbuild; use Tbuild;
57 package body Sem_Eval is
59 -----------------------------------------
60 -- Handling of Compile Time Evaluation --
61 -----------------------------------------
63 -- The compile time evaluation of expressions is distributed over several
64 -- Eval_xxx procedures. These procedures are called immediately after
65 -- a subexpression is resolved and is therefore accomplished in a bottom
66 -- up fashion. The flags are synthesized using the following approach.
68 -- Is_Static_Expression is determined by following the detailed rules
69 -- in RM 4.9(4-14). This involves testing the Is_Static_Expression
70 -- flag of the operands in many cases.
72 -- Raises_Constraint_Error is set if any of the operands have the flag
73 -- set or if an attempt to compute the value of the current expression
74 -- results in detection of a runtime constraint error.
76 -- As described in the spec, the requirement is that Is_Static_Expression
77 -- be accurately set, and in addition for nodes for which this flag is set,
78 -- Raises_Constraint_Error must also be set. Furthermore a node which has
79 -- Is_Static_Expression set, and Raises_Constraint_Error clear, then the
80 -- requirement is that the expression value must be precomputed, and the
81 -- node is either a literal, or the name of a constant entity whose value
82 -- is a static expression.
84 -- The general approach is as follows. First compute Is_Static_Expression.
85 -- If the node is not static, then the flag is left off in the node and
86 -- we are all done. Otherwise for a static node, we test if any of the
87 -- operands will raise constraint error, and if so, propagate the flag
88 -- Raises_Constraint_Error to the result node and we are done (since the
89 -- error was already posted at a lower level).
91 -- For the case of a static node whose operands do not raise constraint
92 -- error, we attempt to evaluate the node. If this evaluation succeeds,
93 -- then the node is replaced by the result of this computation. If the
94 -- evaluation raises constraint error, then we rewrite the node with
95 -- Apply_Compile_Time_Constraint_Error to raise the exception and also
96 -- to post appropriate error messages.
102 type Bits is array (Nat range <>) of Boolean;
103 -- Used to convert unsigned (modular) values for folding logical ops
105 -- The following declarations are used to maintain a cache of nodes that
106 -- have compile time known values. The cache is maintained only for
107 -- discrete types (the most common case), and is populated by calls to
108 -- Compile_Time_Known_Value and Expr_Value, but only used by Expr_Value
109 -- since it is possible for the status to change (in particular it is
110 -- possible for a node to get replaced by a constraint error node).
112 CV_Bits : constant := 5;
113 -- Number of low order bits of Node_Id value used to reference entries
114 -- in the cache table.
116 CV_Cache_Size : constant Nat := 2 ** CV_Bits;
117 -- Size of cache for compile time values
119 subtype CV_Range is Nat range 0 .. CV_Cache_Size;
121 type CV_Entry is record
126 type Match_Result is (Match, No_Match, Non_Static);
127 -- Result returned from functions that test for a matching result. If the
128 -- operands are not OK_Static then Non_Static will be returned. Otherwise
129 -- Match/No_Match is returned depending on whether the match succeeds.
131 type CV_Cache_Array is array (CV_Range) of CV_Entry;
133 CV_Cache : CV_Cache_Array := (others => (Node_High_Bound, Uint_0));
134 -- This is the actual cache, with entries consisting of node/value pairs,
135 -- and the impossible value Node_High_Bound used for unset entries.
137 type Range_Membership is (In_Range, Out_Of_Range, Unknown);
138 -- Range membership may either be statically known to be in range or out
139 -- of range, or not statically known. Used for Test_In_Range below.
141 -----------------------
142 -- Local Subprograms --
143 -----------------------
145 function Choice_Matches
147 Choice : Node_Id) return Match_Result;
148 -- Determines whether given value Expr matches the given Choice. The Expr
149 -- can be of discrete, real, or string type and must be a compile time
150 -- known value (it is an error to make the call if these conditions are
151 -- not met). The choice can be a range, subtype name, subtype indication,
152 -- or expression. The returned result is Non_Static if Choice is not
153 -- OK_Static, otherwise either Match or No_Match is returned depending
154 -- on whether Choice matches Expr. This is used for case expression
155 -- alternatives, and also for membership tests. In each case, more
156 -- possibilities are tested than the syntax allows (e.g. membership allows
157 -- subtype indications and non-discrete types, and case allows an OTHERS
158 -- choice), but it does not matter, since we have already done a full
159 -- semantic and syntax check of the construct, so the extra possibilities
160 -- just will not arise for correct expressions.
162 -- Note: if Choice_Matches finds that a choice raises Constraint_Error, e.g
163 -- a reference to a type, one of whose bounds raises Constraint_Error, then
164 -- it also sets the Raises_Constraint_Error flag on the Choice itself.
166 function Choices_Match
168 Choices : List_Id) return Match_Result;
169 -- This function applies Choice_Matches to each element of Choices. If the
170 -- result is No_Match, then it continues and checks the next element. If
171 -- the result is Match or Non_Static, this result is immediately given
172 -- as the result without checking the rest of the list. Expr can be of
173 -- discrete, real, or string type and must be a compile time known value
174 -- (it is an error to make the call if these conditions are not met).
176 function From_Bits (B : Bits; T : Entity_Id) return Uint;
177 -- Converts a bit string of length B'Length to a Uint value to be used for
178 -- a target of type T, which is a modular type. This procedure includes the
179 -- necessary reduction by the modulus in the case of a non-binary modulus
180 -- (for a binary modulus, the bit string is the right length any way so all
183 function Is_Static_Choice (Choice : Node_Id) return Boolean;
184 -- Given a choice (from a case expression or membership test), returns
185 -- True if the choice is static. No test is made for raising of constraint
186 -- error, so this function is used only for legality tests.
188 function Is_Static_Choice_List (Choices : List_Id) return Boolean;
189 -- Given a choice list (from a case expression or membership test), return
190 -- True if all choices are static in the sense of Is_Static_Choice.
192 function Is_OK_Static_Choice (Choice : Node_Id) return Boolean;
193 -- Given a choice (from a case expression or membership test), returns
194 -- True if the choice is static and does not raise a Constraint_Error.
196 function Is_OK_Static_Choice_List (Choices : List_Id) return Boolean;
197 -- Given a choice list (from a case expression or membership test), return
198 -- True if all choices are static in the sense of Is_OK_Static_Choice.
200 function Is_Static_Range (N : Node_Id) return Boolean;
201 -- Determine if range is static, as defined in RM 4.9(26). The only allowed
202 -- argument is an N_Range node (but note that the semantic analysis of
203 -- equivalent range attribute references already turned them into the
204 -- equivalent range). This differs from Is_OK_Static_Range (which is what
205 -- must be used by clients) in that it does not care whether the bounds
206 -- raise Constraint_Error or not. Used for checking whether expressions are
207 -- static in the 4.9 sense (without worrying about exceptions).
209 function Get_String_Val (N : Node_Id) return Node_Id;
210 -- Given a tree node for a folded string or character value, returns the
211 -- corresponding string literal or character literal (one of the two must
212 -- be available, or the operand would not have been marked as foldable in
213 -- the earlier analysis of the operation).
215 function OK_Bits (N : Node_Id; Bits : Uint) return Boolean;
216 -- Bits represents the number of bits in an integer value to be computed
217 -- (but the value has not been computed yet). If this value in Bits is
218 -- reasonable, a result of True is returned, with the implication that the
219 -- caller should go ahead and complete the calculation. If the value in
220 -- Bits is unreasonably large, then an error is posted on node N, and
221 -- False is returned (and the caller skips the proposed calculation).
223 procedure Out_Of_Range (N : Node_Id);
224 -- This procedure is called if it is determined that node N, which appears
225 -- in a non-static context, is a compile time known value which is outside
226 -- its range, i.e. the range of Etype. This is used in contexts where
227 -- this is an illegality if N is static, and should generate a warning
230 function Real_Or_String_Static_Predicate_Matches
232 Typ : Entity_Id) return Boolean;
233 -- This is the function used to evaluate real or string static predicates.
234 -- Val is an unanalyzed N_Real_Literal or N_String_Literal node, which
235 -- represents the value to be tested against the predicate. Typ is the
236 -- type with the predicate, from which the predicate expression can be
237 -- extracted. The result returned is True if the given value satisfies
240 procedure Rewrite_In_Raise_CE (N : Node_Id; Exp : Node_Id);
241 -- N and Exp are nodes representing an expression, Exp is known to raise
242 -- CE. N is rewritten in term of Exp in the optimal way.
244 function String_Type_Len (Stype : Entity_Id) return Uint;
245 -- Given a string type, determines the length of the index type, or, if
246 -- this index type is non-static, the length of the base type of this index
247 -- type. Note that if the string type is itself static, then the index type
248 -- is static, so the second case applies only if the string type passed is
251 function Test (Cond : Boolean) return Uint;
252 pragma Inline (Test);
253 -- This function simply returns the appropriate Boolean'Pos value
254 -- corresponding to the value of Cond as a universal integer. It is
255 -- used for producing the result of the static evaluation of the
258 function Find_Universal_Operator_Type (N : Node_Id) return Entity_Id;
259 -- Check whether an arithmetic operation with universal operands which is a
260 -- rewritten function call with an explicit scope indication is ambiguous:
261 -- P."+" (1, 2) will be ambiguous if there is more than one visible numeric
262 -- type declared in P and the context does not impose a type on the result
263 -- (e.g. in the expression of a type conversion). If ambiguous, emit an
264 -- error and return Empty, else return the result type of the operator.
266 procedure Test_Expression_Is_Foldable
271 -- Tests to see if expression N whose single operand is Op1 is foldable,
272 -- i.e. the operand value is known at compile time. If the operation is
273 -- foldable, then Fold is True on return, and Stat indicates whether the
274 -- result is static (i.e. the operand was static). Note that it is quite
275 -- possible for Fold to be True, and Stat to be False, since there are
276 -- cases in which we know the value of an operand even though it is not
277 -- technically static (e.g. the static lower bound of a range whose upper
278 -- bound is non-static).
280 -- If Stat is set False on return, then Test_Expression_Is_Foldable makes
281 -- a call to Check_Non_Static_Context on the operand. If Fold is False on
282 -- return, then all processing is complete, and the caller should return,
283 -- since there is nothing else to do.
285 -- If Stat is set True on return, then Is_Static_Expression is also set
286 -- true in node N. There are some cases where this is over-enthusiastic,
287 -- e.g. in the two operand case below, for string comparison, the result is
288 -- not static even though the two operands are static. In such cases, the
289 -- caller must reset the Is_Static_Expression flag in N.
291 -- If Fold and Stat are both set to False then this routine performs also
292 -- the following extra actions:
294 -- If either operand is Any_Type then propagate it to result to prevent
297 -- If some operand raises constraint error, then replace the node N
298 -- with the raise constraint error node. This replacement inherits the
299 -- Is_Static_Expression flag from the operands.
301 procedure Test_Expression_Is_Foldable
307 CRT_Safe : Boolean := False);
308 -- Same processing, except applies to an expression N with two operands
309 -- Op1 and Op2. The result is static only if both operands are static. If
310 -- CRT_Safe is set True, then CRT_Safe_Compile_Time_Known_Value is used
311 -- for the tests that the two operands are known at compile time. See
312 -- spec of this routine for further details.
314 function Test_In_Range
317 Assume_Valid : Boolean;
319 Int_Real : Boolean) return Range_Membership;
320 -- Common processing for Is_In_Range and Is_Out_Of_Range: Returns In_Range
321 -- or Out_Of_Range if it can be guaranteed at compile time that expression
322 -- N is known to be in or out of range of the subtype Typ. If not compile
323 -- time known, Unknown is returned. See documentation of Is_In_Range for
324 -- complete description of parameters.
326 procedure To_Bits (U : Uint; B : out Bits);
327 -- Converts a Uint value to a bit string of length B'Length
329 -----------------------------------------------
330 -- Check_Expression_Against_Static_Predicate --
331 -----------------------------------------------
333 procedure Check_Expression_Against_Static_Predicate
338 -- Nothing to do if expression is not known at compile time, or the
339 -- type has no static predicate set (will be the case for all non-scalar
340 -- types, so no need to make a special test for that).
342 if not (Has_Static_Predicate (Typ)
343 and then Compile_Time_Known_Value (Expr))
348 -- Here we have a static predicate (note that it could have arisen from
349 -- an explicitly specified Dynamic_Predicate whose expression met the
350 -- rules for being predicate-static).
352 -- Case of real static predicate
354 if Is_Real_Type (Typ) then
355 if Real_Or_String_Static_Predicate_Matches
356 (Val => Make_Real_Literal (Sloc (Expr), Expr_Value_R (Expr)),
362 -- Case of string static predicate
364 elsif Is_String_Type (Typ) then
365 if Real_Or_String_Static_Predicate_Matches
366 (Val => Expr_Value_S (Expr), Typ => Typ)
371 -- Case of discrete static predicate
374 pragma Assert (Is_Discrete_Type (Typ));
376 -- If static predicate matches, nothing to do
378 if Choices_Match (Expr, Static_Discrete_Predicate (Typ)) = Match then
383 -- Here we know that the predicate will fail
385 -- Special case of static expression failing a predicate (other than one
386 -- that was explicitly specified with a Dynamic_Predicate aspect). This
387 -- is the case where the expression is no longer considered static.
389 if Is_Static_Expression (Expr)
390 and then not Has_Dynamic_Predicate_Aspect (Typ)
393 ("??static expression fails static predicate check on &",
396 ("\??expression is no longer considered static", Expr);
397 Set_Is_Static_Expression (Expr, False);
399 -- In all other cases, this is just a warning that a test will fail.
400 -- It does not matter if the expression is static or not, or if the
401 -- predicate comes from a dynamic predicate aspect or not.
405 ("??expression fails predicate check on &", Expr, Typ);
407 end Check_Expression_Against_Static_Predicate;
409 ------------------------------
410 -- Check_Non_Static_Context --
411 ------------------------------
413 procedure Check_Non_Static_Context (N : Node_Id) is
414 T : constant Entity_Id := Etype (N);
415 Checks_On : constant Boolean :=
416 not Index_Checks_Suppressed (T)
417 and not Range_Checks_Suppressed (T);
420 -- Ignore cases of non-scalar types, error types, or universal real
421 -- types that have no usable bounds.
424 or else not Is_Scalar_Type (T)
425 or else T = Universal_Fixed
426 or else T = Universal_Real
431 -- At this stage we have a scalar type. If we have an expression that
432 -- raises CE, then we already issued a warning or error msg so there is
433 -- nothing more to be done in this routine.
435 if Raises_Constraint_Error (N) then
439 -- Now we have a scalar type which is not marked as raising a constraint
440 -- error exception. The main purpose of this routine is to deal with
441 -- static expressions appearing in a non-static context. That means
442 -- that if we do not have a static expression then there is not much
443 -- to do. The one case that we deal with here is that if we have a
444 -- floating-point value that is out of range, then we post a warning
445 -- that an infinity will result.
447 if not Is_Static_Expression (N) then
448 if Is_Floating_Point_Type (T)
449 and then Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True)
452 ("??float value out of range, infinity will be generated", N);
458 -- Here we have the case of outer level static expression of scalar
459 -- type, where the processing of this procedure is needed.
461 -- For real types, this is where we convert the value to a machine
462 -- number (see RM 4.9(38)). Also see ACVC test C490001. We should only
463 -- need to do this if the parent is a constant declaration, since in
464 -- other cases, gigi should do the necessary conversion correctly, but
465 -- experimentation shows that this is not the case on all machines, in
466 -- particular if we do not convert all literals to machine values in
467 -- non-static contexts, then ACVC test C490001 fails on Sparc/Solaris
470 if Nkind (N) = N_Real_Literal
471 and then not Is_Machine_Number (N)
472 and then not Is_Generic_Type (Etype (N))
473 and then Etype (N) /= Universal_Real
475 -- Check that value is in bounds before converting to machine
476 -- number, so as not to lose case where value overflows in the
477 -- least significant bit or less. See B490001.
479 if Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True) then
484 -- Note: we have to copy the node, to avoid problems with conformance
485 -- of very similar numbers (see ACVC tests B4A010C and B63103A).
487 Rewrite (N, New_Copy (N));
489 if not Is_Floating_Point_Type (T) then
491 (N, Corresponding_Integer_Value (N) * Small_Value (T));
493 elsif not UR_Is_Zero (Realval (N)) then
495 -- Note: even though RM 4.9(38) specifies biased rounding, this
496 -- has been modified by AI-100 in order to prevent confusing
497 -- differences in rounding between static and non-static
498 -- expressions. AI-100 specifies that the effect of such rounding
499 -- is implementation dependent, and in GNAT we round to nearest
500 -- even to match the run-time behavior.
503 (N, Machine (Base_Type (T), Realval (N), Round_Even, N));
506 Set_Is_Machine_Number (N);
509 -- Check for out of range universal integer. This is a non-static
510 -- context, so the integer value must be in range of the runtime
511 -- representation of universal integers.
513 -- We do this only within an expression, because that is the only
514 -- case in which non-static universal integer values can occur, and
515 -- furthermore, Check_Non_Static_Context is currently (incorrectly???)
516 -- called in contexts like the expression of a number declaration where
517 -- we certainly want to allow out of range values.
519 if Etype (N) = Universal_Integer
520 and then Nkind (N) = N_Integer_Literal
521 and then Nkind (Parent (N)) in N_Subexpr
523 (Intval (N) < Expr_Value (Type_Low_Bound (Universal_Integer))
525 Intval (N) > Expr_Value (Type_High_Bound (Universal_Integer)))
527 Apply_Compile_Time_Constraint_Error
528 (N, "non-static universal integer value out of range<<",
529 CE_Range_Check_Failed);
531 -- Check out of range of base type
533 elsif Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True) then
536 -- Give warning if outside subtype (where one or both of the bounds of
537 -- the subtype is static). This warning is omitted if the expression
538 -- appears in a range that could be null (warnings are handled elsewhere
541 elsif T /= Base_Type (T) and then Nkind (Parent (N)) /= N_Range then
542 if Is_In_Range (N, T, Assume_Valid => True) then
545 elsif Is_Out_Of_Range (N, T, Assume_Valid => True) then
546 Apply_Compile_Time_Constraint_Error
547 (N, "value not in range of}<<", CE_Range_Check_Failed);
550 Enable_Range_Check (N);
553 Set_Do_Range_Check (N, False);
556 end Check_Non_Static_Context;
558 ---------------------------------
559 -- Check_String_Literal_Length --
560 ---------------------------------
562 procedure Check_String_Literal_Length (N : Node_Id; Ttype : Entity_Id) is
564 if not Raises_Constraint_Error (N) and then Is_Constrained (Ttype) then
565 if UI_From_Int (String_Length (Strval (N))) /= String_Type_Len (Ttype)
567 Apply_Compile_Time_Constraint_Error
568 (N, "string length wrong for}??",
569 CE_Length_Check_Failed,
574 end Check_String_Literal_Length;
580 function Choice_Matches
582 Choice : Node_Id) return Match_Result
584 Etyp : constant Entity_Id := Etype (Expr);
590 pragma Assert (Compile_Time_Known_Value (Expr));
591 pragma Assert (Is_Scalar_Type (Etyp) or else Is_String_Type (Etyp));
593 if not Is_OK_Static_Choice (Choice) then
594 Set_Raises_Constraint_Error (Choice);
597 -- Discrete type case
599 elsif Is_Discrete_Type (Etype (Expr)) then
600 Val := Expr_Value (Expr);
602 if Nkind (Choice) = N_Range then
603 if Val >= Expr_Value (Low_Bound (Choice))
605 Val <= Expr_Value (High_Bound (Choice))
612 elsif Nkind (Choice) = N_Subtype_Indication
614 (Is_Entity_Name (Choice) and then Is_Type (Entity (Choice)))
616 if Val >= Expr_Value (Type_Low_Bound (Etype (Choice)))
618 Val <= Expr_Value (Type_High_Bound (Etype (Choice)))
625 elsif Nkind (Choice) = N_Others_Choice then
629 if Val = Expr_Value (Choice) then
638 elsif Is_Real_Type (Etype (Expr)) then
639 ValR := Expr_Value_R (Expr);
641 if Nkind (Choice) = N_Range then
642 if ValR >= Expr_Value_R (Low_Bound (Choice))
644 ValR <= Expr_Value_R (High_Bound (Choice))
651 elsif Nkind (Choice) = N_Subtype_Indication
653 (Is_Entity_Name (Choice) and then Is_Type (Entity (Choice)))
655 if ValR >= Expr_Value_R (Type_Low_Bound (Etype (Choice)))
657 ValR <= Expr_Value_R (Type_High_Bound (Etype (Choice)))
665 if ValR = Expr_Value_R (Choice) then
675 pragma Assert (Is_String_Type (Etype (Expr)));
676 ValS := Expr_Value_S (Expr);
678 if Nkind (Choice) = N_Subtype_Indication
680 (Is_Entity_Name (Choice) and then Is_Type (Entity (Choice)))
682 if not Is_Constrained (Etype (Choice)) then
687 Typlen : constant Uint :=
688 String_Type_Len (Etype (Choice));
689 Strlen : constant Uint :=
690 UI_From_Int (String_Length (Strval (ValS)));
692 if Typlen = Strlen then
701 if String_Equal (Strval (ValS), Strval (Expr_Value_S (Choice)))
715 function Choices_Match
717 Choices : List_Id) return Match_Result
720 Result : Match_Result;
723 Choice := First (Choices);
724 while Present (Choice) loop
725 Result := Choice_Matches (Expr, Choice);
727 if Result /= No_Match then
737 --------------------------
738 -- Compile_Time_Compare --
739 --------------------------
741 function Compile_Time_Compare
743 Assume_Valid : Boolean) return Compare_Result
745 Discard : aliased Uint;
747 return Compile_Time_Compare (L, R, Discard'Access, Assume_Valid);
748 end Compile_Time_Compare;
750 function Compile_Time_Compare
753 Assume_Valid : Boolean;
754 Rec : Boolean := False) return Compare_Result
756 Ltyp : Entity_Id := Underlying_Type (Etype (L));
757 Rtyp : Entity_Id := Underlying_Type (Etype (R));
758 -- These get reset to the base type for the case of entities where
759 -- Is_Known_Valid is not set. This takes care of handling possible
760 -- invalid representations using the value of the base type, in
761 -- accordance with RM 13.9.1(10).
763 Discard : aliased Uint;
765 procedure Compare_Decompose
769 -- This procedure decomposes the node N into an expression node and a
770 -- signed offset, so that the value of N is equal to the value of R plus
771 -- the value V (which may be negative). If no such decomposition is
772 -- possible, then on return R is a copy of N, and V is set to zero.
774 function Compare_Fixup (N : Node_Id) return Node_Id;
775 -- This function deals with replacing 'Last and 'First references with
776 -- their corresponding type bounds, which we then can compare. The
777 -- argument is the original node, the result is the identity, unless we
778 -- have a 'Last/'First reference in which case the value returned is the
779 -- appropriate type bound.
781 function Is_Known_Valid_Operand (Opnd : Node_Id) return Boolean;
782 -- Even if the context does not assume that values are valid, some
783 -- simple cases can be recognized.
785 function Is_Same_Value (L, R : Node_Id) return Boolean;
786 -- Returns True iff L and R represent expressions that definitely have
787 -- identical (but not necessarily compile time known) values Indeed the
788 -- caller is expected to have already dealt with the cases of compile
789 -- time known values, so these are not tested here.
791 -----------------------
792 -- Compare_Decompose --
793 -----------------------
795 procedure Compare_Decompose
801 if Nkind (N) = N_Op_Add
802 and then Nkind (Right_Opnd (N)) = N_Integer_Literal
805 V := Intval (Right_Opnd (N));
808 elsif Nkind (N) = N_Op_Subtract
809 and then Nkind (Right_Opnd (N)) = N_Integer_Literal
812 V := UI_Negate (Intval (Right_Opnd (N)));
815 elsif Nkind (N) = N_Attribute_Reference then
816 if Attribute_Name (N) = Name_Succ then
817 R := First (Expressions (N));
821 elsif Attribute_Name (N) = Name_Pred then
822 R := First (Expressions (N));
830 end Compare_Decompose;
836 function Compare_Fixup (N : Node_Id) return Node_Id is
842 -- Fixup only required for First/Last attribute reference
844 if Nkind (N) = N_Attribute_Reference
845 and then Nam_In (Attribute_Name (N), Name_First, Name_Last)
847 Xtyp := Etype (Prefix (N));
849 -- If we have no type, then just abandon the attempt to do
850 -- a fixup, this is probably the result of some other error.
856 -- Dereference an access type
858 if Is_Access_Type (Xtyp) then
859 Xtyp := Designated_Type (Xtyp);
862 -- If we don't have an array type at this stage, something is
863 -- peculiar, e.g. another error, and we abandon the attempt at
866 if not Is_Array_Type (Xtyp) then
870 -- Ignore unconstrained array, since bounds are not meaningful
872 if not Is_Constrained (Xtyp) then
876 if Ekind (Xtyp) = E_String_Literal_Subtype then
877 if Attribute_Name (N) = Name_First then
878 return String_Literal_Low_Bound (Xtyp);
881 Make_Integer_Literal (Sloc (N),
882 Intval => Intval (String_Literal_Low_Bound (Xtyp)) +
883 String_Literal_Length (Xtyp));
887 -- Find correct index type
889 Indx := First_Index (Xtyp);
891 if Present (Expressions (N)) then
892 Subs := UI_To_Int (Expr_Value (First (Expressions (N))));
894 for J in 2 .. Subs loop
895 Indx := Next_Index (Indx);
899 Xtyp := Etype (Indx);
901 if Attribute_Name (N) = Name_First then
902 return Type_Low_Bound (Xtyp);
904 return Type_High_Bound (Xtyp);
911 ----------------------------
912 -- Is_Known_Valid_Operand --
913 ----------------------------
915 function Is_Known_Valid_Operand (Opnd : Node_Id) return Boolean is
917 return (Is_Entity_Name (Opnd)
919 (Is_Known_Valid (Entity (Opnd))
920 or else Ekind (Entity (Opnd)) = E_In_Parameter
922 (Ekind (Entity (Opnd)) in Object_Kind
923 and then Present (Current_Value (Entity (Opnd))))))
924 or else Is_OK_Static_Expression (Opnd);
925 end Is_Known_Valid_Operand;
931 function Is_Same_Value (L, R : Node_Id) return Boolean is
932 Lf : constant Node_Id := Compare_Fixup (L);
933 Rf : constant Node_Id := Compare_Fixup (R);
935 function Is_Same_Subscript (L, R : List_Id) return Boolean;
936 -- L, R are the Expressions values from two attribute nodes for First
937 -- or Last attributes. Either may be set to No_List if no expressions
938 -- are present (indicating subscript 1). The result is True if both
939 -- expressions represent the same subscript (note one case is where
940 -- one subscript is missing and the other is explicitly set to 1).
942 -----------------------
943 -- Is_Same_Subscript --
944 -----------------------
946 function Is_Same_Subscript (L, R : List_Id) return Boolean is
952 return Expr_Value (First (R)) = Uint_1;
957 return Expr_Value (First (L)) = Uint_1;
959 return Expr_Value (First (L)) = Expr_Value (First (R));
962 end Is_Same_Subscript;
964 -- Start of processing for Is_Same_Value
967 -- Values are the same if they refer to the same entity and the
968 -- entity is non-volatile. This does not however apply to Float
969 -- types, since we may have two NaN values and they should never
972 -- If the entity is a discriminant, the two expressions may be bounds
973 -- of components of objects of the same discriminated type. The
974 -- values of the discriminants are not static, and therefore the
975 -- result is unknown.
977 -- It would be better to comment individual branches of this test ???
979 if Nkind_In (Lf, N_Identifier, N_Expanded_Name)
980 and then Nkind_In (Rf, N_Identifier, N_Expanded_Name)
981 and then Entity (Lf) = Entity (Rf)
982 and then Ekind (Entity (Lf)) /= E_Discriminant
983 and then Present (Entity (Lf))
984 and then not Is_Floating_Point_Type (Etype (L))
985 and then not Is_Volatile_Reference (L)
986 and then not Is_Volatile_Reference (R)
990 -- Or if they are compile time known and identical
992 elsif Compile_Time_Known_Value (Lf)
994 Compile_Time_Known_Value (Rf)
995 and then Expr_Value (Lf) = Expr_Value (Rf)
999 -- False if Nkind of the two nodes is different for remaining cases
1001 elsif Nkind (Lf) /= Nkind (Rf) then
1004 -- True if both 'First or 'Last values applying to the same entity
1005 -- (first and last don't change even if value does). Note that we
1006 -- need this even with the calls to Compare_Fixup, to handle the
1007 -- case of unconstrained array attributes where Compare_Fixup
1008 -- cannot find useful bounds.
1010 elsif Nkind (Lf) = N_Attribute_Reference
1011 and then Attribute_Name (Lf) = Attribute_Name (Rf)
1012 and then Nam_In (Attribute_Name (Lf), Name_First, Name_Last)
1013 and then Nkind_In (Prefix (Lf), N_Identifier, N_Expanded_Name)
1014 and then Nkind_In (Prefix (Rf), N_Identifier, N_Expanded_Name)
1015 and then Entity (Prefix (Lf)) = Entity (Prefix (Rf))
1016 and then Is_Same_Subscript (Expressions (Lf), Expressions (Rf))
1020 -- True if the same selected component from the same record
1022 elsif Nkind (Lf) = N_Selected_Component
1023 and then Selector_Name (Lf) = Selector_Name (Rf)
1024 and then Is_Same_Value (Prefix (Lf), Prefix (Rf))
1028 -- True if the same unary operator applied to the same operand
1030 elsif Nkind (Lf) in N_Unary_Op
1031 and then Is_Same_Value (Right_Opnd (Lf), Right_Opnd (Rf))
1035 -- True if the same binary operator applied to the same operands
1037 elsif Nkind (Lf) in N_Binary_Op
1038 and then Is_Same_Value (Left_Opnd (Lf), Left_Opnd (Rf))
1039 and then Is_Same_Value (Right_Opnd (Lf), Right_Opnd (Rf))
1043 -- All other cases, we can't tell, so return False
1050 -- Start of processing for Compile_Time_Compare
1053 Diff.all := No_Uint;
1055 -- In preanalysis mode, always return Unknown unless the expression
1056 -- is static. It is too early to be thinking we know the result of a
1057 -- comparison, save that judgment for the full analysis. This is
1058 -- particularly important in the case of pre and postconditions, which
1059 -- otherwise can be prematurely collapsed into having True or False
1060 -- conditions when this is inappropriate.
1062 if not (Full_Analysis
1063 or else (Is_OK_Static_Expression (L)
1065 Is_OK_Static_Expression (R)))
1070 -- If either operand could raise constraint error, then we cannot
1071 -- know the result at compile time (since CE may be raised).
1073 if not (Cannot_Raise_Constraint_Error (L)
1075 Cannot_Raise_Constraint_Error (R))
1080 -- Identical operands are most certainly equal
1085 -- If expressions have no types, then do not attempt to determine if
1086 -- they are the same, since something funny is going on. One case in
1087 -- which this happens is during generic template analysis, when bounds
1088 -- are not fully analyzed.
1090 elsif No (Ltyp) or else No (Rtyp) then
1093 -- We do not attempt comparisons for packed arrays arrays represented as
1094 -- modular types, where the semantics of comparison is quite different.
1096 elsif Is_Packed_Array_Impl_Type (Ltyp)
1097 and then Is_Modular_Integer_Type (Ltyp)
1101 -- For access types, the only time we know the result at compile time
1102 -- (apart from identical operands, which we handled already) is if we
1103 -- know one operand is null and the other is not, or both operands are
1106 elsif Is_Access_Type (Ltyp) then
1107 if Known_Null (L) then
1108 if Known_Null (R) then
1110 elsif Known_Non_Null (R) then
1116 elsif Known_Non_Null (L) and then Known_Null (R) then
1123 -- Case where comparison involves two compile time known values
1125 elsif Compile_Time_Known_Value (L)
1127 Compile_Time_Known_Value (R)
1129 -- For the floating-point case, we have to be a little careful, since
1130 -- at compile time we are dealing with universal exact values, but at
1131 -- runtime, these will be in non-exact target form. That's why the
1132 -- returned results are LE and GE below instead of LT and GT.
1134 if Is_Floating_Point_Type (Ltyp)
1136 Is_Floating_Point_Type (Rtyp)
1139 Lo : constant Ureal := Expr_Value_R (L);
1140 Hi : constant Ureal := Expr_Value_R (R);
1151 -- For string types, we have two string literals and we proceed to
1152 -- compare them using the Ada style dictionary string comparison.
1154 elsif not Is_Scalar_Type (Ltyp) then
1156 Lstring : constant String_Id := Strval (Expr_Value_S (L));
1157 Rstring : constant String_Id := Strval (Expr_Value_S (R));
1158 Llen : constant Nat := String_Length (Lstring);
1159 Rlen : constant Nat := String_Length (Rstring);
1162 for J in 1 .. Nat'Min (Llen, Rlen) loop
1164 LC : constant Char_Code := Get_String_Char (Lstring, J);
1165 RC : constant Char_Code := Get_String_Char (Rstring, J);
1177 elsif Llen > Rlen then
1184 -- For remaining scalar cases we know exactly (note that this does
1185 -- include the fixed-point case, where we know the run time integer
1190 Lo : constant Uint := Expr_Value (L);
1191 Hi : constant Uint := Expr_Value (R);
1194 Diff.all := Hi - Lo;
1199 Diff.all := Lo - Hi;
1205 -- Cases where at least one operand is not known at compile time
1208 -- Remaining checks apply only for discrete types
1210 if not Is_Discrete_Type (Ltyp)
1212 not Is_Discrete_Type (Rtyp)
1217 -- Defend against generic types, or actually any expressions that
1218 -- contain a reference to a generic type from within a generic
1219 -- template. We don't want to do any range analysis of such
1220 -- expressions for two reasons. First, the bounds of a generic type
1221 -- itself are junk and cannot be used for any kind of analysis.
1222 -- Second, we may have a case where the range at run time is indeed
1223 -- known, but we don't want to do compile time analysis in the
1224 -- template based on that range since in an instance the value may be
1225 -- static, and able to be elaborated without reference to the bounds
1226 -- of types involved. As an example, consider:
1228 -- (F'Pos (F'Last) + 1) > Integer'Last
1230 -- The expression on the left side of > is Universal_Integer and thus
1231 -- acquires the type Integer for evaluation at run time, and at run
1232 -- time it is true that this condition is always False, but within
1233 -- an instance F may be a type with a static range greater than the
1234 -- range of Integer, and the expression statically evaluates to True.
1236 if References_Generic_Formal_Type (L)
1238 References_Generic_Formal_Type (R)
1243 -- Replace types by base types for the case of values which are not
1244 -- known to have valid representations. This takes care of properly
1245 -- dealing with invalid representations.
1247 if not Assume_Valid then
1248 if not (Is_Entity_Name (L)
1249 and then (Is_Known_Valid (Entity (L))
1250 or else Assume_No_Invalid_Values))
1252 Ltyp := Underlying_Type (Base_Type (Ltyp));
1255 if not (Is_Entity_Name (R)
1256 and then (Is_Known_Valid (Entity (R))
1257 or else Assume_No_Invalid_Values))
1259 Rtyp := Underlying_Type (Base_Type (Rtyp));
1263 -- First attempt is to decompose the expressions to extract a
1264 -- constant offset resulting from the use of any of the forms:
1271 -- Then we see if the two expressions are the same value, and if so
1272 -- the result is obtained by comparing the offsets.
1274 -- Note: the reason we do this test first is that it returns only
1275 -- decisive results (with diff set), where other tests, like the
1276 -- range test, may not be as so decisive. Consider for example
1277 -- J .. J + 1. This code can conclude LT with a difference of 1,
1278 -- even if the range of J is not known.
1287 Compare_Decompose (L, Lnode, Loffs);
1288 Compare_Decompose (R, Rnode, Roffs);
1290 if Is_Same_Value (Lnode, Rnode) then
1291 if Loffs = Roffs then
1293 elsif Loffs < Roffs then
1294 Diff.all := Roffs - Loffs;
1297 Diff.all := Loffs - Roffs;
1303 -- Next, try range analysis and see if operand ranges are disjoint
1311 -- True if each range is a single point
1314 Determine_Range (L, LOK, LLo, LHi, Assume_Valid);
1315 Determine_Range (R, ROK, RLo, RHi, Assume_Valid);
1318 Single := (LLo = LHi) and then (RLo = RHi);
1321 if Single and Assume_Valid then
1322 Diff.all := RLo - LLo;
1327 elsif RHi < LLo then
1328 if Single and Assume_Valid then
1329 Diff.all := LLo - RLo;
1334 elsif Single and then LLo = RLo then
1336 -- If the range includes a single literal and we can assume
1337 -- validity then the result is known even if an operand is
1340 if Assume_Valid then
1346 elsif LHi = RLo then
1349 elsif RHi = LLo then
1352 elsif not Is_Known_Valid_Operand (L)
1353 and then not Assume_Valid
1355 if Is_Same_Value (L, R) then
1362 -- If the range of either operand cannot be determined, nothing
1363 -- further can be inferred.
1370 -- Here is where we check for comparisons against maximum bounds of
1371 -- types, where we know that no value can be outside the bounds of
1372 -- the subtype. Note that this routine is allowed to assume that all
1373 -- expressions are within their subtype bounds. Callers wishing to
1374 -- deal with possibly invalid values must in any case take special
1375 -- steps (e.g. conversions to larger types) to avoid this kind of
1376 -- optimization, which is always considered to be valid. We do not
1377 -- attempt this optimization with generic types, since the type
1378 -- bounds may not be meaningful in this case.
1380 -- We are in danger of an infinite recursion here. It does not seem
1381 -- useful to go more than one level deep, so the parameter Rec is
1382 -- used to protect ourselves against this infinite recursion.
1386 -- See if we can get a decisive check against one operand and a
1387 -- bound of the other operand (four possible tests here). Note
1388 -- that we avoid testing junk bounds of a generic type.
1390 if not Is_Generic_Type (Rtyp) then
1391 case Compile_Time_Compare (L, Type_Low_Bound (Rtyp),
1393 Assume_Valid, Rec => True)
1395 when LT => return LT;
1396 when LE => return LE;
1397 when EQ => return LE;
1398 when others => null;
1401 case Compile_Time_Compare (L, Type_High_Bound (Rtyp),
1403 Assume_Valid, Rec => True)
1405 when GT => return GT;
1406 when GE => return GE;
1407 when EQ => return GE;
1408 when others => null;
1412 if not Is_Generic_Type (Ltyp) then
1413 case Compile_Time_Compare (Type_Low_Bound (Ltyp), R,
1415 Assume_Valid, Rec => True)
1417 when GT => return GT;
1418 when GE => return GE;
1419 when EQ => return GE;
1420 when others => null;
1423 case Compile_Time_Compare (Type_High_Bound (Ltyp), R,
1425 Assume_Valid, Rec => True)
1427 when LT => return LT;
1428 when LE => return LE;
1429 when EQ => return LE;
1430 when others => null;
1435 -- Next attempt is to see if we have an entity compared with a
1436 -- compile time known value, where there is a current value
1437 -- conditional for the entity which can tell us the result.
1441 -- Entity variable (left operand)
1444 -- Value (right operand)
1447 -- If False, we have reversed the operands
1450 -- Comparison operator kind from Get_Current_Value_Condition call
1453 -- Value from Get_Current_Value_Condition call
1458 Result : Compare_Result;
1459 -- Known result before inversion
1462 if Is_Entity_Name (L)
1463 and then Compile_Time_Known_Value (R)
1466 Val := Expr_Value (R);
1469 elsif Is_Entity_Name (R)
1470 and then Compile_Time_Known_Value (L)
1473 Val := Expr_Value (L);
1476 -- That was the last chance at finding a compile time result
1482 Get_Current_Value_Condition (Var, Op, Opn);
1484 -- That was the last chance, so if we got nothing return
1490 Opv := Expr_Value (Opn);
1492 -- We got a comparison, so we might have something interesting
1494 -- Convert LE to LT and GE to GT, just so we have fewer cases
1496 if Op = N_Op_Le then
1500 elsif Op = N_Op_Ge then
1505 -- Deal with equality case
1507 if Op = N_Op_Eq then
1510 elsif Opv < Val then
1516 -- Deal with inequality case
1518 elsif Op = N_Op_Ne then
1525 -- Deal with greater than case
1527 elsif Op = N_Op_Gt then
1530 elsif Opv = Val - 1 then
1536 -- Deal with less than case
1538 else pragma Assert (Op = N_Op_Lt);
1541 elsif Opv = Val + 1 then
1548 -- Deal with inverting result
1552 when GT => return LT;
1553 when GE => return LE;
1554 when LT => return GT;
1555 when LE => return GE;
1556 when others => return Result;
1563 end Compile_Time_Compare;
1565 -------------------------------
1566 -- Compile_Time_Known_Bounds --
1567 -------------------------------
1569 function Compile_Time_Known_Bounds (T : Entity_Id) return Boolean is
1574 if T = Any_Composite or else not Is_Array_Type (T) then
1578 Indx := First_Index (T);
1579 while Present (Indx) loop
1580 Typ := Underlying_Type (Etype (Indx));
1582 -- Never look at junk bounds of a generic type
1584 if Is_Generic_Type (Typ) then
1588 -- Otherwise check bounds for compile time known
1590 if not Compile_Time_Known_Value (Type_Low_Bound (Typ)) then
1592 elsif not Compile_Time_Known_Value (Type_High_Bound (Typ)) then
1600 end Compile_Time_Known_Bounds;
1602 ------------------------------
1603 -- Compile_Time_Known_Value --
1604 ------------------------------
1606 function Compile_Time_Known_Value (Op : Node_Id) return Boolean is
1607 K : constant Node_Kind := Nkind (Op);
1608 CV_Ent : CV_Entry renames CV_Cache (Nat (Op) mod CV_Cache_Size);
1611 -- Never known at compile time if bad type or raises constraint error
1612 -- or empty (latter case occurs only as a result of a previous error).
1615 Check_Error_Detected;
1619 or else Etype (Op) = Any_Type
1620 or else Raises_Constraint_Error (Op)
1625 -- If we have an entity name, then see if it is the name of a constant
1626 -- and if so, test the corresponding constant value, or the name of
1627 -- an enumeration literal, which is always a constant.
1629 if Present (Etype (Op)) and then Is_Entity_Name (Op) then
1631 E : constant Entity_Id := Entity (Op);
1635 -- Never known at compile time if it is a packed array value.
1636 -- We might want to try to evaluate these at compile time one
1637 -- day, but we do not make that attempt now.
1639 if Is_Packed_Array_Impl_Type (Etype (Op)) then
1643 if Ekind (E) = E_Enumeration_Literal then
1646 elsif Ekind (E) = E_Constant then
1647 V := Constant_Value (E);
1648 return Present (V) and then Compile_Time_Known_Value (V);
1652 -- We have a value, see if it is compile time known
1655 -- Integer literals are worth storing in the cache
1657 if K = N_Integer_Literal then
1659 CV_Ent.V := Intval (Op);
1662 -- Other literals and NULL are known at compile time
1665 Nkind_In (K, N_Character_Literal,
1674 -- If we fall through, not known at compile time
1678 -- If we get an exception while trying to do this test, then some error
1679 -- has occurred, and we simply say that the value is not known after all
1684 end Compile_Time_Known_Value;
1686 --------------------------------------
1687 -- Compile_Time_Known_Value_Or_Aggr --
1688 --------------------------------------
1690 function Compile_Time_Known_Value_Or_Aggr (Op : Node_Id) return Boolean is
1692 -- If we have an entity name, then see if it is the name of a constant
1693 -- and if so, test the corresponding constant value, or the name of
1694 -- an enumeration literal, which is always a constant.
1696 if Is_Entity_Name (Op) then
1698 E : constant Entity_Id := Entity (Op);
1702 if Ekind (E) = E_Enumeration_Literal then
1705 elsif Ekind (E) /= E_Constant then
1709 V := Constant_Value (E);
1711 and then Compile_Time_Known_Value_Or_Aggr (V);
1715 -- We have a value, see if it is compile time known
1718 if Compile_Time_Known_Value (Op) then
1721 elsif Nkind (Op) = N_Aggregate then
1723 if Present (Expressions (Op)) then
1727 Expr := First (Expressions (Op));
1728 while Present (Expr) loop
1729 if not Compile_Time_Known_Value_Or_Aggr (Expr) then
1738 if Present (Component_Associations (Op)) then
1743 Cass := First (Component_Associations (Op));
1744 while Present (Cass) loop
1746 Compile_Time_Known_Value_Or_Aggr (Expression (Cass))
1758 -- All other types of values are not known at compile time
1765 end Compile_Time_Known_Value_Or_Aggr;
1767 ---------------------------------------
1768 -- CRT_Safe_Compile_Time_Known_Value --
1769 ---------------------------------------
1771 function CRT_Safe_Compile_Time_Known_Value (Op : Node_Id) return Boolean is
1773 if (Configurable_Run_Time_Mode or No_Run_Time_Mode)
1774 and then not Is_OK_Static_Expression (Op)
1778 return Compile_Time_Known_Value (Op);
1780 end CRT_Safe_Compile_Time_Known_Value;
1786 -- This is only called for actuals of functions that are not predefined
1787 -- operators (which have already been rewritten as operators at this
1788 -- stage), so the call can never be folded, and all that needs doing for
1789 -- the actual is to do the check for a non-static context.
1791 procedure Eval_Actual (N : Node_Id) is
1793 Check_Non_Static_Context (N);
1796 --------------------
1797 -- Eval_Allocator --
1798 --------------------
1800 -- Allocators are never static, so all we have to do is to do the
1801 -- check for a non-static context if an expression is present.
1803 procedure Eval_Allocator (N : Node_Id) is
1804 Expr : constant Node_Id := Expression (N);
1806 if Nkind (Expr) = N_Qualified_Expression then
1807 Check_Non_Static_Context (Expression (Expr));
1811 ------------------------
1812 -- Eval_Arithmetic_Op --
1813 ------------------------
1815 -- Arithmetic operations are static functions, so the result is static
1816 -- if both operands are static (RM 4.9(7), 4.9(20)).
1818 procedure Eval_Arithmetic_Op (N : Node_Id) is
1819 Left : constant Node_Id := Left_Opnd (N);
1820 Right : constant Node_Id := Right_Opnd (N);
1821 Ltype : constant Entity_Id := Etype (Left);
1822 Rtype : constant Entity_Id := Etype (Right);
1823 Otype : Entity_Id := Empty;
1828 -- If not foldable we are done
1830 Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
1836 -- Otherwise attempt to fold
1838 if Is_Universal_Numeric_Type (Etype (Left))
1840 Is_Universal_Numeric_Type (Etype (Right))
1842 Otype := Find_Universal_Operator_Type (N);
1845 -- Fold for cases where both operands are of integer type
1847 if Is_Integer_Type (Ltype) and then Is_Integer_Type (Rtype) then
1849 Left_Int : constant Uint := Expr_Value (Left);
1850 Right_Int : constant Uint := Expr_Value (Right);
1856 Result := Left_Int + Right_Int;
1858 when N_Op_Subtract =>
1859 Result := Left_Int - Right_Int;
1861 when N_Op_Multiply =>
1864 (Num_Bits (Left_Int) + Num_Bits (Right_Int)))
1866 Result := Left_Int * Right_Int;
1873 -- The exception Constraint_Error is raised by integer
1874 -- division, rem and mod if the right operand is zero.
1876 if Right_Int = 0 then
1877 Apply_Compile_Time_Constraint_Error
1878 (N, "division by zero", CE_Divide_By_Zero,
1880 Set_Raises_Constraint_Error (N);
1883 -- Otherwise we can do the division
1886 Result := Left_Int / Right_Int;
1891 -- The exception Constraint_Error is raised by integer
1892 -- division, rem and mod if the right operand is zero.
1894 if Right_Int = 0 then
1895 Apply_Compile_Time_Constraint_Error
1896 (N, "mod with zero divisor", CE_Divide_By_Zero,
1900 Result := Left_Int mod Right_Int;
1905 -- The exception Constraint_Error is raised by integer
1906 -- division, rem and mod if the right operand is zero.
1908 if Right_Int = 0 then
1909 Apply_Compile_Time_Constraint_Error
1910 (N, "rem with zero divisor", CE_Divide_By_Zero,
1915 Result := Left_Int rem Right_Int;
1919 raise Program_Error;
1922 -- Adjust the result by the modulus if the type is a modular type
1924 if Is_Modular_Integer_Type (Ltype) then
1925 Result := Result mod Modulus (Ltype);
1927 -- For a signed integer type, check non-static overflow
1929 elsif (not Stat) and then Is_Signed_Integer_Type (Ltype) then
1931 BT : constant Entity_Id := Base_Type (Ltype);
1932 Lo : constant Uint := Expr_Value (Type_Low_Bound (BT));
1933 Hi : constant Uint := Expr_Value (Type_High_Bound (BT));
1935 if Result < Lo or else Result > Hi then
1936 Apply_Compile_Time_Constraint_Error
1937 (N, "value not in range of }??",
1938 CE_Overflow_Check_Failed,
1945 -- If we get here we can fold the result
1947 Fold_Uint (N, Result, Stat);
1950 -- Cases where at least one operand is a real. We handle the cases of
1951 -- both reals, or mixed/real integer cases (the latter happen only for
1952 -- divide and multiply, and the result is always real).
1954 elsif Is_Real_Type (Ltype) or else Is_Real_Type (Rtype) then
1961 if Is_Real_Type (Ltype) then
1962 Left_Real := Expr_Value_R (Left);
1964 Left_Real := UR_From_Uint (Expr_Value (Left));
1967 if Is_Real_Type (Rtype) then
1968 Right_Real := Expr_Value_R (Right);
1970 Right_Real := UR_From_Uint (Expr_Value (Right));
1973 if Nkind (N) = N_Op_Add then
1974 Result := Left_Real + Right_Real;
1976 elsif Nkind (N) = N_Op_Subtract then
1977 Result := Left_Real - Right_Real;
1979 elsif Nkind (N) = N_Op_Multiply then
1980 Result := Left_Real * Right_Real;
1982 else pragma Assert (Nkind (N) = N_Op_Divide);
1983 if UR_Is_Zero (Right_Real) then
1984 Apply_Compile_Time_Constraint_Error
1985 (N, "division by zero", CE_Divide_By_Zero);
1989 Result := Left_Real / Right_Real;
1992 Fold_Ureal (N, Result, Stat);
1996 -- If the operator was resolved to a specific type, make sure that type
1997 -- is frozen even if the expression is folded into a literal (which has
1998 -- a universal type).
2000 if Present (Otype) then
2001 Freeze_Before (N, Otype);
2003 end Eval_Arithmetic_Op;
2005 ----------------------------
2006 -- Eval_Character_Literal --
2007 ----------------------------
2009 -- Nothing to be done
2011 procedure Eval_Character_Literal (N : Node_Id) is
2012 pragma Warnings (Off, N);
2015 end Eval_Character_Literal;
2021 -- Static function calls are either calls to predefined operators
2022 -- with static arguments, or calls to functions that rename a literal.
2023 -- Only the latter case is handled here, predefined operators are
2024 -- constant-folded elsewhere.
2026 -- If the function is itself inherited (see 7423-001) the literal of
2027 -- the parent type must be explicitly converted to the return type
2030 procedure Eval_Call (N : Node_Id) is
2031 Loc : constant Source_Ptr := Sloc (N);
2032 Typ : constant Entity_Id := Etype (N);
2036 if Nkind (N) = N_Function_Call
2037 and then No (Parameter_Associations (N))
2038 and then Is_Entity_Name (Name (N))
2039 and then Present (Alias (Entity (Name (N))))
2040 and then Is_Enumeration_Type (Base_Type (Typ))
2042 Lit := Ultimate_Alias (Entity (Name (N)));
2044 if Ekind (Lit) = E_Enumeration_Literal then
2045 if Base_Type (Etype (Lit)) /= Base_Type (Typ) then
2047 (N, Convert_To (Typ, New_Occurrence_Of (Lit, Loc)));
2049 Rewrite (N, New_Occurrence_Of (Lit, Loc));
2057 --------------------------
2058 -- Eval_Case_Expression --
2059 --------------------------
2061 -- A conditional expression is static if all its conditions and dependent
2062 -- expressions are static. Note that we do not care if the dependent
2063 -- expressions raise CE, except for the one that will be selected.
2065 procedure Eval_Case_Expression (N : Node_Id) is
2070 Set_Is_Static_Expression (N, False);
2072 if not Is_Static_Expression (Expression (N)) then
2073 Check_Non_Static_Context (Expression (N));
2077 -- First loop, make sure all the alternatives are static expressions
2078 -- none of which raise Constraint_Error. We make the constraint error
2079 -- check because part of the legality condition for a correct static
2080 -- case expression is that the cases are covered, like any other case
2081 -- expression. And we can't do that if any of the conditions raise an
2082 -- exception, so we don't even try to evaluate if that is the case.
2084 Alt := First (Alternatives (N));
2085 while Present (Alt) loop
2087 -- The expression must be static, but we don't care at this stage
2088 -- if it raises Constraint_Error (the alternative might not match,
2089 -- in which case the expression is statically unevaluated anyway).
2091 if not Is_Static_Expression (Expression (Alt)) then
2092 Check_Non_Static_Context (Expression (Alt));
2096 -- The choices of a case always have to be static, and cannot raise
2097 -- an exception. If this condition is not met, then the expression
2098 -- is plain illegal, so just abandon evaluation attempts. No need
2099 -- to check non-static context when we have something illegal anyway.
2101 if not Is_OK_Static_Choice_List (Discrete_Choices (Alt)) then
2108 -- OK, if the above loop gets through it means that all choices are OK
2109 -- static (don't raise exceptions), so the whole case is static, and we
2110 -- can find the matching alternative.
2112 Set_Is_Static_Expression (N);
2114 -- Now to deal with propagating a possible constraint error
2116 -- If the selecting expression raises CE, propagate and we are done
2118 if Raises_Constraint_Error (Expression (N)) then
2119 Set_Raises_Constraint_Error (N);
2121 -- Otherwise we need to check the alternatives to find the matching
2122 -- one. CE's in other than the matching one are not relevant. But we
2123 -- do need to check the matching one. Unlike the first loop, we do not
2124 -- have to go all the way through, when we find the matching one, quit.
2127 Alt := First (Alternatives (N));
2130 -- We must find a match among the alternatives. If not, this must
2131 -- be due to other errors, so just ignore, leaving as non-static.
2134 Set_Is_Static_Expression (N, False);
2138 -- Otherwise loop through choices of this alternative
2140 Choice := First (Discrete_Choices (Alt));
2141 while Present (Choice) loop
2143 -- If we find a matching choice, then the Expression of this
2144 -- alternative replaces N (Raises_Constraint_Error flag is
2145 -- included, so we don't have to special case that).
2147 if Choice_Matches (Expression (N), Choice) = Match then
2148 Rewrite (N, Relocate_Node (Expression (Alt)));
2158 end Eval_Case_Expression;
2160 ------------------------
2161 -- Eval_Concatenation --
2162 ------------------------
2164 -- Concatenation is a static function, so the result is static if both
2165 -- operands are static (RM 4.9(7), 4.9(21)).
2167 procedure Eval_Concatenation (N : Node_Id) is
2168 Left : constant Node_Id := Left_Opnd (N);
2169 Right : constant Node_Id := Right_Opnd (N);
2170 C_Typ : constant Entity_Id := Root_Type (Component_Type (Etype (N)));
2175 -- Concatenation is never static in Ada 83, so if Ada 83 check operand
2176 -- non-static context.
2178 if Ada_Version = Ada_83
2179 and then Comes_From_Source (N)
2181 Check_Non_Static_Context (Left);
2182 Check_Non_Static_Context (Right);
2186 -- If not foldable we are done. In principle concatenation that yields
2187 -- any string type is static (i.e. an array type of character types).
2188 -- However, character types can include enumeration literals, and
2189 -- concatenation in that case cannot be described by a literal, so we
2190 -- only consider the operation static if the result is an array of
2191 -- (a descendant of) a predefined character type.
2193 Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
2195 if not (Is_Standard_Character_Type (C_Typ) and then Fold) then
2196 Set_Is_Static_Expression (N, False);
2200 -- Compile time string concatenation
2202 -- ??? Note that operands that are aggregates can be marked as static,
2203 -- so we should attempt at a later stage to fold concatenations with
2207 Left_Str : constant Node_Id := Get_String_Val (Left);
2209 Right_Str : constant Node_Id := Get_String_Val (Right);
2210 Folded_Val : String_Id;
2213 -- Establish new string literal, and store left operand. We make
2214 -- sure to use the special Start_String that takes an operand if
2215 -- the left operand is a string literal. Since this is optimized
2216 -- in the case where that is the most recently created string
2217 -- literal, we ensure efficient time/space behavior for the
2218 -- case of a concatenation of a series of string literals.
2220 if Nkind (Left_Str) = N_String_Literal then
2221 Left_Len := String_Length (Strval (Left_Str));
2223 -- If the left operand is the empty string, and the right operand
2224 -- is a string literal (the case of "" & "..."), the result is the
2225 -- value of the right operand. This optimization is important when
2226 -- Is_Folded_In_Parser, to avoid copying an enormous right
2229 if Left_Len = 0 and then Nkind (Right_Str) = N_String_Literal then
2230 Folded_Val := Strval (Right_Str);
2232 Start_String (Strval (Left_Str));
2237 Store_String_Char (UI_To_CC (Char_Literal_Value (Left_Str)));
2241 -- Now append the characters of the right operand, unless we
2242 -- optimized the "" & "..." case above.
2244 if Nkind (Right_Str) = N_String_Literal then
2245 if Left_Len /= 0 then
2246 Store_String_Chars (Strval (Right_Str));
2247 Folded_Val := End_String;
2250 Store_String_Char (UI_To_CC (Char_Literal_Value (Right_Str)));
2251 Folded_Val := End_String;
2254 Set_Is_Static_Expression (N, Stat);
2256 -- If left operand is the empty string, the result is the
2257 -- right operand, including its bounds if anomalous.
2260 and then Is_Array_Type (Etype (Right))
2261 and then Etype (Right) /= Any_String
2263 Set_Etype (N, Etype (Right));
2266 Fold_Str (N, Folded_Val, Static => Stat);
2268 end Eval_Concatenation;
2270 ----------------------
2271 -- Eval_Entity_Name --
2272 ----------------------
2274 -- This procedure is used for identifiers and expanded names other than
2275 -- named numbers (see Eval_Named_Integer, Eval_Named_Real. These are
2276 -- static if they denote a static constant (RM 4.9(6)) or if the name
2277 -- denotes an enumeration literal (RM 4.9(22)).
2279 procedure Eval_Entity_Name (N : Node_Id) is
2280 Def_Id : constant Entity_Id := Entity (N);
2284 -- Enumeration literals are always considered to be constants
2285 -- and cannot raise constraint error (RM 4.9(22)).
2287 if Ekind (Def_Id) = E_Enumeration_Literal then
2288 Set_Is_Static_Expression (N);
2291 -- A name is static if it denotes a static constant (RM 4.9(5)), and
2292 -- we also copy Raise_Constraint_Error. Notice that even if non-static,
2293 -- it does not violate 10.2.1(8) here, since this is not a variable.
2295 elsif Ekind (Def_Id) = E_Constant then
2297 -- Deferred constants must always be treated as nonstatic outside the
2298 -- scope of their full view.
2300 if Present (Full_View (Def_Id))
2301 and then not In_Open_Scopes (Scope (Def_Id))
2305 Val := Constant_Value (Def_Id);
2308 if Present (Val) then
2309 Set_Is_Static_Expression
2310 (N, Is_Static_Expression (Val)
2311 and then Is_Static_Subtype (Etype (Def_Id)));
2312 Set_Raises_Constraint_Error (N, Raises_Constraint_Error (Val));
2314 if not Is_Static_Expression (N)
2315 and then not Is_Generic_Type (Etype (N))
2317 Validate_Static_Object_Name (N);
2320 -- Mark constant condition in SCOs
2323 and then Comes_From_Source (N)
2324 and then Is_Boolean_Type (Etype (Def_Id))
2325 and then Compile_Time_Known_Value (N)
2327 Set_SCO_Condition (N, Expr_Value_E (N) = Standard_True);
2334 -- Fall through if the name is not static
2336 Validate_Static_Object_Name (N);
2337 end Eval_Entity_Name;
2339 ------------------------
2340 -- Eval_If_Expression --
2341 ------------------------
2343 -- We can fold to a static expression if the condition and both dependent
2344 -- expressions are static. Otherwise, the only required processing is to do
2345 -- the check for non-static context for the then and else expressions.
2347 procedure Eval_If_Expression (N : Node_Id) is
2348 Condition : constant Node_Id := First (Expressions (N));
2349 Then_Expr : constant Node_Id := Next (Condition);
2350 Else_Expr : constant Node_Id := Next (Then_Expr);
2352 Non_Result : Node_Id;
2354 Rstat : constant Boolean :=
2355 Is_Static_Expression (Condition)
2357 Is_Static_Expression (Then_Expr)
2359 Is_Static_Expression (Else_Expr);
2360 -- True if result is static
2363 -- If result not static, nothing to do, otherwise set static result
2368 Set_Is_Static_Expression (N);
2371 -- If any operand is Any_Type, just propagate to result and do not try
2372 -- to fold, this prevents cascaded errors.
2374 if Etype (Condition) = Any_Type or else
2375 Etype (Then_Expr) = Any_Type or else
2376 Etype (Else_Expr) = Any_Type
2378 Set_Etype (N, Any_Type);
2379 Set_Is_Static_Expression (N, False);
2383 -- If condition raises constraint error then we have already signaled
2384 -- an error, and we just propagate to the result and do not fold.
2386 if Raises_Constraint_Error (Condition) then
2387 Set_Raises_Constraint_Error (N);
2391 -- Static case where we can fold. Note that we don't try to fold cases
2392 -- where the condition is known at compile time, but the result is
2393 -- non-static. This avoids possible cases of infinite recursion where
2394 -- the expander puts in a redundant test and we remove it. Instead we
2395 -- deal with these cases in the expander.
2397 -- Select result operand
2399 if Is_True (Expr_Value (Condition)) then
2400 Result := Then_Expr;
2401 Non_Result := Else_Expr;
2403 Result := Else_Expr;
2404 Non_Result := Then_Expr;
2407 -- Note that it does not matter if the non-result operand raises a
2408 -- Constraint_Error, but if the result raises constraint error then we
2409 -- replace the node with a raise constraint error. This will properly
2410 -- propagate Raises_Constraint_Error since this flag is set in Result.
2412 if Raises_Constraint_Error (Result) then
2413 Rewrite_In_Raise_CE (N, Result);
2414 Check_Non_Static_Context (Non_Result);
2416 -- Otherwise the result operand replaces the original node
2419 Rewrite (N, Relocate_Node (Result));
2420 Set_Is_Static_Expression (N);
2422 end Eval_If_Expression;
2424 ----------------------------
2425 -- Eval_Indexed_Component --
2426 ----------------------------
2428 -- Indexed components are never static, so we need to perform the check
2429 -- for non-static context on the index values. Then, we check if the
2430 -- value can be obtained at compile time, even though it is non-static.
2432 procedure Eval_Indexed_Component (N : Node_Id) is
2436 -- Check for non-static context on index values
2438 Expr := First (Expressions (N));
2439 while Present (Expr) loop
2440 Check_Non_Static_Context (Expr);
2444 -- If the indexed component appears in an object renaming declaration
2445 -- then we do not want to try to evaluate it, since in this case we
2446 -- need the identity of the array element.
2448 if Nkind (Parent (N)) = N_Object_Renaming_Declaration then
2451 -- Similarly if the indexed component appears as the prefix of an
2452 -- attribute we don't want to evaluate it, because at least for
2453 -- some cases of attributes we need the identify (e.g. Access, Size)
2455 elsif Nkind (Parent (N)) = N_Attribute_Reference then
2459 -- Note: there are other cases, such as the left side of an assignment,
2460 -- or an OUT parameter for a call, where the replacement results in the
2461 -- illegal use of a constant, But these cases are illegal in the first
2462 -- place, so the replacement, though silly, is harmless.
2464 -- Now see if this is a constant array reference
2466 if List_Length (Expressions (N)) = 1
2467 and then Is_Entity_Name (Prefix (N))
2468 and then Ekind (Entity (Prefix (N))) = E_Constant
2469 and then Present (Constant_Value (Entity (Prefix (N))))
2472 Loc : constant Source_Ptr := Sloc (N);
2473 Arr : constant Node_Id := Constant_Value (Entity (Prefix (N)));
2474 Sub : constant Node_Id := First (Expressions (N));
2480 -- Linear one's origin subscript value for array reference
2483 -- Lower bound of the first array index
2486 -- Value from constant array
2489 Atyp := Etype (Arr);
2491 if Is_Access_Type (Atyp) then
2492 Atyp := Designated_Type (Atyp);
2495 -- If we have an array type (we should have but perhaps there are
2496 -- error cases where this is not the case), then see if we can do
2497 -- a constant evaluation of the array reference.
2499 if Is_Array_Type (Atyp) and then Atyp /= Any_Composite then
2500 if Ekind (Atyp) = E_String_Literal_Subtype then
2501 Lbd := String_Literal_Low_Bound (Atyp);
2503 Lbd := Type_Low_Bound (Etype (First_Index (Atyp)));
2506 if Compile_Time_Known_Value (Sub)
2507 and then Nkind (Arr) = N_Aggregate
2508 and then Compile_Time_Known_Value (Lbd)
2509 and then Is_Discrete_Type (Component_Type (Atyp))
2511 Lin := UI_To_Int (Expr_Value (Sub) - Expr_Value (Lbd)) + 1;
2513 if List_Length (Expressions (Arr)) >= Lin then
2514 Elm := Pick (Expressions (Arr), Lin);
2516 -- If the resulting expression is compile time known,
2517 -- then we can rewrite the indexed component with this
2518 -- value, being sure to mark the result as non-static.
2519 -- We also reset the Sloc, in case this generates an
2520 -- error later on (e.g. 136'Access).
2522 if Compile_Time_Known_Value (Elm) then
2523 Rewrite (N, Duplicate_Subexpr_No_Checks (Elm));
2524 Set_Is_Static_Expression (N, False);
2529 -- We can also constant-fold if the prefix is a string literal.
2530 -- This will be useful in an instantiation or an inlining.
2532 elsif Compile_Time_Known_Value (Sub)
2533 and then Nkind (Arr) = N_String_Literal
2534 and then Compile_Time_Known_Value (Lbd)
2535 and then Expr_Value (Lbd) = 1
2536 and then Expr_Value (Sub) <=
2537 String_Literal_Length (Etype (Arr))
2540 C : constant Char_Code :=
2541 Get_String_Char (Strval (Arr),
2542 UI_To_Int (Expr_Value (Sub)));
2544 Set_Character_Literal_Name (C);
2547 Make_Character_Literal (Loc,
2549 Char_Literal_Value => UI_From_CC (C));
2550 Set_Etype (Elm, Component_Type (Atyp));
2551 Rewrite (N, Duplicate_Subexpr_No_Checks (Elm));
2552 Set_Is_Static_Expression (N, False);
2558 end Eval_Indexed_Component;
2560 --------------------------
2561 -- Eval_Integer_Literal --
2562 --------------------------
2564 -- Numeric literals are static (RM 4.9(1)), and have already been marked
2565 -- as static by the analyzer. The reason we did it that early is to allow
2566 -- the possibility of turning off the Is_Static_Expression flag after
2567 -- analysis, but before resolution, when integer literals are generated in
2568 -- the expander that do not correspond to static expressions.
2570 procedure Eval_Integer_Literal (N : Node_Id) is
2571 T : constant Entity_Id := Etype (N);
2573 function In_Any_Integer_Context return Boolean;
2574 -- If the literal is resolved with a specific type in a context where
2575 -- the expected type is Any_Integer, there are no range checks on the
2576 -- literal. By the time the literal is evaluated, it carries the type
2577 -- imposed by the enclosing expression, and we must recover the context
2578 -- to determine that Any_Integer is meant.
2580 ----------------------------
2581 -- In_Any_Integer_Context --
2582 ----------------------------
2584 function In_Any_Integer_Context return Boolean is
2585 Par : constant Node_Id := Parent (N);
2586 K : constant Node_Kind := Nkind (Par);
2589 -- Any_Integer also appears in digits specifications for real types,
2590 -- but those have bounds smaller that those of any integer base type,
2591 -- so we can safely ignore these cases.
2593 return Nkind_In (K, N_Number_Declaration,
2594 N_Attribute_Reference,
2595 N_Attribute_Definition_Clause,
2596 N_Modular_Type_Definition,
2597 N_Signed_Integer_Type_Definition);
2598 end In_Any_Integer_Context;
2600 -- Start of processing for Eval_Integer_Literal
2604 -- If the literal appears in a non-expression context, then it is
2605 -- certainly appearing in a non-static context, so check it. This is
2606 -- actually a redundant check, since Check_Non_Static_Context would
2607 -- check it, but it seems worth while avoiding the call.
2609 if Nkind (Parent (N)) not in N_Subexpr
2610 and then not In_Any_Integer_Context
2612 Check_Non_Static_Context (N);
2615 -- Modular integer literals must be in their base range
2617 if Is_Modular_Integer_Type (T)
2618 and then Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True)
2622 end Eval_Integer_Literal;
2624 ---------------------
2625 -- Eval_Logical_Op --
2626 ---------------------
2628 -- Logical operations are static functions, so the result is potentially
2629 -- static if both operands are potentially static (RM 4.9(7), 4.9(20)).
2631 procedure Eval_Logical_Op (N : Node_Id) is
2632 Left : constant Node_Id := Left_Opnd (N);
2633 Right : constant Node_Id := Right_Opnd (N);
2638 -- If not foldable we are done
2640 Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
2646 -- Compile time evaluation of logical operation
2649 Left_Int : constant Uint := Expr_Value (Left);
2650 Right_Int : constant Uint := Expr_Value (Right);
2653 if Is_Modular_Integer_Type (Etype (N)) then
2655 Left_Bits : Bits (0 .. UI_To_Int (Esize (Etype (N))) - 1);
2656 Right_Bits : Bits (0 .. UI_To_Int (Esize (Etype (N))) - 1);
2659 To_Bits (Left_Int, Left_Bits);
2660 To_Bits (Right_Int, Right_Bits);
2662 -- Note: should really be able to use array ops instead of
2663 -- these loops, but they weren't working at the time ???
2665 if Nkind (N) = N_Op_And then
2666 for J in Left_Bits'Range loop
2667 Left_Bits (J) := Left_Bits (J) and Right_Bits (J);
2670 elsif Nkind (N) = N_Op_Or then
2671 for J in Left_Bits'Range loop
2672 Left_Bits (J) := Left_Bits (J) or Right_Bits (J);
2676 pragma Assert (Nkind (N) = N_Op_Xor);
2678 for J in Left_Bits'Range loop
2679 Left_Bits (J) := Left_Bits (J) xor Right_Bits (J);
2683 Fold_Uint (N, From_Bits (Left_Bits, Etype (N)), Stat);
2687 pragma Assert (Is_Boolean_Type (Etype (N)));
2689 if Nkind (N) = N_Op_And then
2691 Test (Is_True (Left_Int) and then Is_True (Right_Int)), Stat);
2693 elsif Nkind (N) = N_Op_Or then
2695 Test (Is_True (Left_Int) or else Is_True (Right_Int)), Stat);
2698 pragma Assert (Nkind (N) = N_Op_Xor);
2700 Test (Is_True (Left_Int) xor Is_True (Right_Int)), Stat);
2704 end Eval_Logical_Op;
2706 ------------------------
2707 -- Eval_Membership_Op --
2708 ------------------------
2710 -- A membership test is potentially static if the expression is static, and
2711 -- the range is a potentially static range, or is a subtype mark denoting a
2712 -- static subtype (RM 4.9(12)).
2714 procedure Eval_Membership_Op (N : Node_Id) is
2715 Left : constant Node_Id := Left_Opnd (N);
2716 Right : constant Node_Id := Right_Opnd (N);
2717 Alts : constant List_Id := Alternatives (N);
2718 Result : Match_Result;
2721 -- Ignore if error in either operand, except to make sure that Any_Type
2722 -- is properly propagated to avoid junk cascaded errors.
2724 if Etype (Left) = Any_Type
2725 or else (Present (Right) and then Etype (Right) = Any_Type)
2727 Set_Etype (N, Any_Type);
2731 -- Ignore if types involved have predicates
2732 -- Is this right for static predicates ???
2733 -- And what about the alternatives ???
2735 if Present (Predicate_Function (Etype (Left)))
2736 or else (Present (Right)
2737 and then Present (Predicate_Function (Etype (Right))))
2742 -- If left operand non-static, then nothing to do
2744 if not Is_Static_Expression (Left) then
2748 -- If choice is non-static, left operand is in non-static context
2750 if (Present (Right) and then not Is_Static_Choice (Right))
2751 or else (Present (Alts) and then not Is_Static_Choice_List (Alts))
2753 Check_Non_Static_Context (Left);
2757 -- Otherwise we definitely have a static expression
2759 Set_Is_Static_Expression (N);
2761 -- If left operand raises constraint error, propagate and we are done
2763 if Raises_Constraint_Error (Left) then
2764 Set_Raises_Constraint_Error (N, True);
2769 if Present (Right) then
2770 Result := Choice_Matches (Left, Right);
2772 Result := Choices_Match (Left, Alts);
2775 -- If result is Non_Static, it means that we raise Constraint_Error,
2776 -- since we already tested that the operands were themselves static.
2778 if Result = Non_Static then
2779 Set_Raises_Constraint_Error (N);
2781 -- Otherwise we have our result (flipped if NOT IN case)
2785 (N, Test ((Result = Match) xor (Nkind (N) = N_Not_In)), True);
2786 Warn_On_Known_Condition (N);
2789 end Eval_Membership_Op;
2791 ------------------------
2792 -- Eval_Named_Integer --
2793 ------------------------
2795 procedure Eval_Named_Integer (N : Node_Id) is
2798 Expr_Value (Expression (Declaration_Node (Entity (N)))), True);
2799 end Eval_Named_Integer;
2801 ---------------------
2802 -- Eval_Named_Real --
2803 ---------------------
2805 procedure Eval_Named_Real (N : Node_Id) is
2808 Expr_Value_R (Expression (Declaration_Node (Entity (N)))), True);
2809 end Eval_Named_Real;
2815 -- Exponentiation is a static functions, so the result is potentially
2816 -- static if both operands are potentially static (RM 4.9(7), 4.9(20)).
2818 procedure Eval_Op_Expon (N : Node_Id) is
2819 Left : constant Node_Id := Left_Opnd (N);
2820 Right : constant Node_Id := Right_Opnd (N);
2825 -- If not foldable we are done
2827 Test_Expression_Is_Foldable
2828 (N, Left, Right, Stat, Fold, CRT_Safe => True);
2830 -- Return if not foldable
2836 if Configurable_Run_Time_Mode and not Stat then
2840 -- Fold exponentiation operation
2843 Right_Int : constant Uint := Expr_Value (Right);
2848 if Is_Integer_Type (Etype (Left)) then
2850 Left_Int : constant Uint := Expr_Value (Left);
2854 -- Exponentiation of an integer raises Constraint_Error for a
2855 -- negative exponent (RM 4.5.6).
2857 if Right_Int < 0 then
2858 Apply_Compile_Time_Constraint_Error
2859 (N, "integer exponent negative", CE_Range_Check_Failed,
2864 if OK_Bits (N, Num_Bits (Left_Int) * Right_Int) then
2865 Result := Left_Int ** Right_Int;
2870 if Is_Modular_Integer_Type (Etype (N)) then
2871 Result := Result mod Modulus (Etype (N));
2874 Fold_Uint (N, Result, Stat);
2882 Left_Real : constant Ureal := Expr_Value_R (Left);
2885 -- Cannot have a zero base with a negative exponent
2887 if UR_Is_Zero (Left_Real) then
2889 if Right_Int < 0 then
2890 Apply_Compile_Time_Constraint_Error
2891 (N, "zero ** negative integer", CE_Range_Check_Failed,
2895 Fold_Ureal (N, Ureal_0, Stat);
2899 Fold_Ureal (N, Left_Real ** Right_Int, Stat);
2910 -- The not operation is a static functions, so the result is potentially
2911 -- static if the operand is potentially static (RM 4.9(7), 4.9(20)).
2913 procedure Eval_Op_Not (N : Node_Id) is
2914 Right : constant Node_Id := Right_Opnd (N);
2919 -- If not foldable we are done
2921 Test_Expression_Is_Foldable (N, Right, Stat, Fold);
2927 -- Fold not operation
2930 Rint : constant Uint := Expr_Value (Right);
2931 Typ : constant Entity_Id := Etype (N);
2934 -- Negation is equivalent to subtracting from the modulus minus one.
2935 -- For a binary modulus this is equivalent to the ones-complement of
2936 -- the original value. For non-binary modulus this is an arbitrary
2937 -- but consistent definition.
2939 if Is_Modular_Integer_Type (Typ) then
2940 Fold_Uint (N, Modulus (Typ) - 1 - Rint, Stat);
2941 else pragma Assert (Is_Boolean_Type (Typ));
2942 Fold_Uint (N, Test (not Is_True (Rint)), Stat);
2945 Set_Is_Static_Expression (N, Stat);
2949 -------------------------------
2950 -- Eval_Qualified_Expression --
2951 -------------------------------
2953 -- A qualified expression is potentially static if its subtype mark denotes
2954 -- a static subtype and its expression is potentially static (RM 4.9 (11)).
2956 procedure Eval_Qualified_Expression (N : Node_Id) is
2957 Operand : constant Node_Id := Expression (N);
2958 Target_Type : constant Entity_Id := Entity (Subtype_Mark (N));
2965 -- Can only fold if target is string or scalar and subtype is static.
2966 -- Also, do not fold if our parent is an allocator (this is because the
2967 -- qualified expression is really part of the syntactic structure of an
2968 -- allocator, and we do not want to end up with something that
2969 -- corresponds to "new 1" where the 1 is the result of folding a
2970 -- qualified expression).
2972 if not Is_Static_Subtype (Target_Type)
2973 or else Nkind (Parent (N)) = N_Allocator
2975 Check_Non_Static_Context (Operand);
2977 -- If operand is known to raise constraint_error, set the flag on the
2978 -- expression so it does not get optimized away.
2980 if Nkind (Operand) = N_Raise_Constraint_Error then
2981 Set_Raises_Constraint_Error (N);
2987 -- If not foldable we are done
2989 Test_Expression_Is_Foldable (N, Operand, Stat, Fold);
2994 -- Don't try fold if target type has constraint error bounds
2996 elsif not Is_OK_Static_Subtype (Target_Type) then
2997 Set_Raises_Constraint_Error (N);
3001 -- Here we will fold, save Print_In_Hex indication
3003 Hex := Nkind (Operand) = N_Integer_Literal
3004 and then Print_In_Hex (Operand);
3006 -- Fold the result of qualification
3008 if Is_Discrete_Type (Target_Type) then
3009 Fold_Uint (N, Expr_Value (Operand), Stat);
3011 -- Preserve Print_In_Hex indication
3013 if Hex and then Nkind (N) = N_Integer_Literal then
3014 Set_Print_In_Hex (N);
3017 elsif Is_Real_Type (Target_Type) then
3018 Fold_Ureal (N, Expr_Value_R (Operand), Stat);
3021 Fold_Str (N, Strval (Get_String_Val (Operand)), Stat);
3024 Set_Is_Static_Expression (N, False);
3026 Check_String_Literal_Length (N, Target_Type);
3032 -- The expression may be foldable but not static
3034 Set_Is_Static_Expression (N, Stat);
3036 if Is_Out_Of_Range (N, Etype (N), Assume_Valid => True) then
3039 end Eval_Qualified_Expression;
3041 -----------------------
3042 -- Eval_Real_Literal --
3043 -----------------------
3045 -- Numeric literals are static (RM 4.9(1)), and have already been marked
3046 -- as static by the analyzer. The reason we did it that early is to allow
3047 -- the possibility of turning off the Is_Static_Expression flag after
3048 -- analysis, but before resolution, when integer literals are generated
3049 -- in the expander that do not correspond to static expressions.
3051 procedure Eval_Real_Literal (N : Node_Id) is
3052 PK : constant Node_Kind := Nkind (Parent (N));
3055 -- If the literal appears in a non-expression context and not as part of
3056 -- a number declaration, then it is appearing in a non-static context,
3059 if PK not in N_Subexpr and then PK /= N_Number_Declaration then
3060 Check_Non_Static_Context (N);
3062 end Eval_Real_Literal;
3064 ------------------------
3065 -- Eval_Relational_Op --
3066 ------------------------
3068 -- Relational operations are static functions, so the result is static if
3069 -- both operands are static (RM 4.9(7), 4.9(20)), except that for strings,
3070 -- the result is never static, even if the operands are.
3072 -- However, for internally generated nodes, we allow string equality and
3073 -- inequality to be static. This is because we rewrite A in "ABC" as an
3074 -- equality test A = "ABC", and the former is definitely static.
3076 procedure Eval_Relational_Op (N : Node_Id) is
3077 Left : constant Node_Id := Left_Opnd (N);
3078 Right : constant Node_Id := Right_Opnd (N);
3079 Typ : constant Entity_Id := Etype (Left);
3080 Otype : Entity_Id := Empty;
3084 -- One special case to deal with first. If we can tell that the result
3085 -- will be false because the lengths of one or more index subtypes are
3086 -- compile time known and different, then we can replace the entire
3087 -- result by False. We only do this for one dimensional arrays, because
3088 -- the case of multi-dimensional arrays is rare and too much trouble. If
3089 -- one of the operands is an illegal aggregate, its type might still be
3090 -- an arbitrary composite type, so nothing to do.
3092 if Is_Array_Type (Typ)
3093 and then Typ /= Any_Composite
3094 and then Number_Dimensions (Typ) = 1
3095 and then (Nkind (N) = N_Op_Eq or else Nkind (N) = N_Op_Ne)
3097 if Raises_Constraint_Error (Left)
3099 Raises_Constraint_Error (Right)
3104 -- OK, we have the case where we may be able to do this fold
3106 Length_Mismatch : declare
3107 procedure Get_Static_Length (Op : Node_Id; Len : out Uint);
3108 -- If Op is an expression for a constrained array with a known at
3109 -- compile time length, then Len is set to this (non-negative
3110 -- length). Otherwise Len is set to minus 1.
3112 -----------------------
3113 -- Get_Static_Length --
3114 -----------------------
3116 procedure Get_Static_Length (Op : Node_Id; Len : out Uint) is
3120 -- First easy case string literal
3122 if Nkind (Op) = N_String_Literal then
3123 Len := UI_From_Int (String_Length (Strval (Op)));
3127 -- Second easy case, not constrained subtype, so no length
3129 if not Is_Constrained (Etype (Op)) then
3130 Len := Uint_Minus_1;
3136 T := Etype (First_Index (Etype (Op)));
3138 -- The simple case, both bounds are known at compile time
3140 if Is_Discrete_Type (T)
3141 and then Compile_Time_Known_Value (Type_Low_Bound (T))
3142 and then Compile_Time_Known_Value (Type_High_Bound (T))
3144 Len := UI_Max (Uint_0,
3145 Expr_Value (Type_High_Bound (T)) -
3146 Expr_Value (Type_Low_Bound (T)) + 1);
3150 -- A more complex case, where the bounds are of the form
3151 -- X [+/- K1] .. X [+/- K2]), where X is an expression that is
3152 -- either A'First or A'Last (with A an entity name), or X is an
3153 -- entity name, and the two X's are the same and K1 and K2 are
3154 -- known at compile time, in this case, the length can also be
3155 -- computed at compile time, even though the bounds are not
3156 -- known. A common case of this is e.g. (X'First .. X'First+5).
3158 Extract_Length : declare
3159 procedure Decompose_Expr
3161 Ent : out Entity_Id;
3162 Kind : out Character;
3164 -- Given an expression see if it is of the form given above,
3165 -- X [+/- K]. If so Ent is set to the entity in X, Kind is
3166 -- 'F','L','E' for 'First/'Last/simple entity, and Cons is
3167 -- the value of K. If the expression is not of the required
3168 -- form, Ent is set to Empty.
3170 --------------------
3171 -- Decompose_Expr --
3172 --------------------
3174 procedure Decompose_Expr
3176 Ent : out Entity_Id;
3177 Kind : out Character;
3183 if Nkind (Expr) = N_Op_Add
3184 and then Compile_Time_Known_Value (Right_Opnd (Expr))
3186 Exp := Left_Opnd (Expr);
3187 Cons := Expr_Value (Right_Opnd (Expr));
3189 elsif Nkind (Expr) = N_Op_Subtract
3190 and then Compile_Time_Known_Value (Right_Opnd (Expr))
3192 Exp := Left_Opnd (Expr);
3193 Cons := -Expr_Value (Right_Opnd (Expr));
3195 -- If the bound is a constant created to remove side
3196 -- effects, recover original expression to see if it has
3197 -- one of the recognizable forms.
3199 elsif Nkind (Expr) = N_Identifier
3200 and then not Comes_From_Source (Entity (Expr))
3201 and then Ekind (Entity (Expr)) = E_Constant
3203 Nkind (Parent (Entity (Expr))) = N_Object_Declaration
3205 Exp := Expression (Parent (Entity (Expr)));
3206 Decompose_Expr (Exp, Ent, Kind, Cons);
3208 -- If original expression includes an entity, create a
3209 -- reference to it for use below.
3211 if Present (Ent) then
3212 Exp := New_Occurrence_Of (Ent, Sloc (Ent));
3220 -- At this stage Exp is set to the potential X
3222 if Nkind (Exp) = N_Attribute_Reference then
3223 if Attribute_Name (Exp) = Name_First then
3225 elsif Attribute_Name (Exp) = Name_Last then
3232 Exp := Prefix (Exp);
3238 if Is_Entity_Name (Exp) and then Present (Entity (Exp))
3240 Ent := Entity (Exp);
3248 Ent1, Ent2 : Entity_Id;
3249 Kind1, Kind2 : Character;
3250 Cons1, Cons2 : Uint;
3252 -- Start of processing for Extract_Length
3256 (Original_Node (Type_Low_Bound (T)), Ent1, Kind1, Cons1);
3258 (Original_Node (Type_High_Bound (T)), Ent2, Kind2, Cons2);
3261 and then Kind1 = Kind2
3262 and then Ent1 = Ent2
3264 Len := Cons2 - Cons1 + 1;
3266 Len := Uint_Minus_1;
3269 end Get_Static_Length;
3276 -- Start of processing for Length_Mismatch
3279 Get_Static_Length (Left, Len_L);
3280 Get_Static_Length (Right, Len_R);
3282 if Len_L /= Uint_Minus_1
3283 and then Len_R /= Uint_Minus_1
3284 and then Len_L /= Len_R
3286 Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False);
3287 Warn_On_Known_Condition (N);
3290 end Length_Mismatch;
3294 Is_Static_Expression : Boolean;
3296 Is_Foldable : Boolean;
3297 pragma Unreferenced (Is_Foldable);
3300 -- Initialize the value of Is_Static_Expression. The value of
3301 -- Is_Foldable returned by Test_Expression_Is_Foldable is not needed
3302 -- since, even when some operand is a variable, we can still perform
3303 -- the static evaluation of the expression in some cases (for
3304 -- example, for a variable of a subtype of Integer we statically
3305 -- know that any value stored in such variable is smaller than
3308 Test_Expression_Is_Foldable
3309 (N, Left, Right, Is_Static_Expression, Is_Foldable);
3311 -- Only comparisons of scalars can give static results. In
3312 -- particular, comparisons of strings never yield a static
3313 -- result, even if both operands are static strings, except that
3314 -- as noted above, we allow equality/inequality for strings.
3316 if Is_String_Type (Typ)
3317 and then not Comes_From_Source (N)
3318 and then Nkind_In (N, N_Op_Eq, N_Op_Ne)
3322 elsif not Is_Scalar_Type (Typ) then
3323 Is_Static_Expression := False;
3324 Set_Is_Static_Expression (N, False);
3327 -- For operators on universal numeric types called as functions with
3328 -- an explicit scope, determine appropriate specific numeric type,
3329 -- and diagnose possible ambiguity.
3331 if Is_Universal_Numeric_Type (Etype (Left))
3333 Is_Universal_Numeric_Type (Etype (Right))
3335 Otype := Find_Universal_Operator_Type (N);
3338 -- For static real type expressions, do not use Compile_Time_Compare
3339 -- since it worries about run-time results which are not exact.
3341 if Is_Static_Expression and then Is_Real_Type (Typ) then
3343 Left_Real : constant Ureal := Expr_Value_R (Left);
3344 Right_Real : constant Ureal := Expr_Value_R (Right);
3348 when N_Op_Eq => Result := (Left_Real = Right_Real);
3349 when N_Op_Ne => Result := (Left_Real /= Right_Real);
3350 when N_Op_Lt => Result := (Left_Real < Right_Real);
3351 when N_Op_Le => Result := (Left_Real <= Right_Real);
3352 when N_Op_Gt => Result := (Left_Real > Right_Real);
3353 when N_Op_Ge => Result := (Left_Real >= Right_Real);
3356 raise Program_Error;
3359 Fold_Uint (N, Test (Result), True);
3362 -- For all other cases, we use Compile_Time_Compare to do the compare
3366 CR : constant Compare_Result :=
3367 Compile_Time_Compare
3368 (Left, Right, Assume_Valid => False);
3371 if CR = Unknown then
3379 elsif CR = NE or else CR = GT or else CR = LT then
3386 if CR = NE or else CR = GT or else CR = LT then
3397 elsif CR = EQ or else CR = GT or else CR = GE then
3404 if CR = LT or else CR = EQ or else CR = LE then
3415 elsif CR = EQ or else CR = LT or else CR = LE then
3422 if CR = GT or else CR = EQ or else CR = GE then
3431 raise Program_Error;
3435 Fold_Uint (N, Test (Result), Is_Static_Expression);
3439 -- For the case of a folded relational operator on a specific numeric
3440 -- type, freeze operand type now.
3442 if Present (Otype) then
3443 Freeze_Before (N, Otype);
3446 Warn_On_Known_Condition (N);
3447 end Eval_Relational_Op;
3453 -- Shift operations are intrinsic operations that can never be static, so
3454 -- the only processing required is to perform the required check for a non
3455 -- static context for the two operands.
3457 -- Actually we could do some compile time evaluation here some time ???
3459 procedure Eval_Shift (N : Node_Id) is
3461 Check_Non_Static_Context (Left_Opnd (N));
3462 Check_Non_Static_Context (Right_Opnd (N));
3465 ------------------------
3466 -- Eval_Short_Circuit --
3467 ------------------------
3469 -- A short circuit operation is potentially static if both operands are
3470 -- potentially static (RM 4.9 (13)).
3472 procedure Eval_Short_Circuit (N : Node_Id) is
3473 Kind : constant Node_Kind := Nkind (N);
3474 Left : constant Node_Id := Left_Opnd (N);
3475 Right : constant Node_Id := Right_Opnd (N);
3478 Rstat : constant Boolean :=
3479 Is_Static_Expression (Left)
3481 Is_Static_Expression (Right);
3484 -- Short circuit operations are never static in Ada 83
3486 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
3487 Check_Non_Static_Context (Left);
3488 Check_Non_Static_Context (Right);
3492 -- Now look at the operands, we can't quite use the normal call to
3493 -- Test_Expression_Is_Foldable here because short circuit operations
3494 -- are a special case, they can still be foldable, even if the right
3495 -- operand raises constraint error.
3497 -- If either operand is Any_Type, just propagate to result and do not
3498 -- try to fold, this prevents cascaded errors.
3500 if Etype (Left) = Any_Type or else Etype (Right) = Any_Type then
3501 Set_Etype (N, Any_Type);
3504 -- If left operand raises constraint error, then replace node N with
3505 -- the raise constraint error node, and we are obviously not foldable.
3506 -- Is_Static_Expression is set from the two operands in the normal way,
3507 -- and we check the right operand if it is in a non-static context.
3509 elsif Raises_Constraint_Error (Left) then
3511 Check_Non_Static_Context (Right);
3514 Rewrite_In_Raise_CE (N, Left);
3515 Set_Is_Static_Expression (N, Rstat);
3518 -- If the result is not static, then we won't in any case fold
3520 elsif not Rstat then
3521 Check_Non_Static_Context (Left);
3522 Check_Non_Static_Context (Right);
3526 -- Here the result is static, note that, unlike the normal processing
3527 -- in Test_Expression_Is_Foldable, we did *not* check above to see if
3528 -- the right operand raises constraint error, that's because it is not
3529 -- significant if the left operand is decisive.
3531 Set_Is_Static_Expression (N);
3533 -- It does not matter if the right operand raises constraint error if
3534 -- it will not be evaluated. So deal specially with the cases where
3535 -- the right operand is not evaluated. Note that we will fold these
3536 -- cases even if the right operand is non-static, which is fine, but
3537 -- of course in these cases the result is not potentially static.
3539 Left_Int := Expr_Value (Left);
3541 if (Kind = N_And_Then and then Is_False (Left_Int))
3543 (Kind = N_Or_Else and then Is_True (Left_Int))
3545 Fold_Uint (N, Left_Int, Rstat);
3549 -- If first operand not decisive, then it does matter if the right
3550 -- operand raises constraint error, since it will be evaluated, so
3551 -- we simply replace the node with the right operand. Note that this
3552 -- properly propagates Is_Static_Expression and Raises_Constraint_Error
3553 -- (both are set to True in Right).
3555 if Raises_Constraint_Error (Right) then
3556 Rewrite_In_Raise_CE (N, Right);
3557 Check_Non_Static_Context (Left);
3561 -- Otherwise the result depends on the right operand
3563 Fold_Uint (N, Expr_Value (Right), Rstat);
3565 end Eval_Short_Circuit;
3571 -- Slices can never be static, so the only processing required is to check
3572 -- for non-static context if an explicit range is given.
3574 procedure Eval_Slice (N : Node_Id) is
3575 Drange : constant Node_Id := Discrete_Range (N);
3578 if Nkind (Drange) = N_Range then
3579 Check_Non_Static_Context (Low_Bound (Drange));
3580 Check_Non_Static_Context (High_Bound (Drange));
3583 -- A slice of the form A (subtype), when the subtype is the index of
3584 -- the type of A, is redundant, the slice can be replaced with A, and
3585 -- this is worth a warning.
3587 if Is_Entity_Name (Prefix (N)) then
3589 E : constant Entity_Id := Entity (Prefix (N));
3590 T : constant Entity_Id := Etype (E);
3593 if Ekind (E) = E_Constant
3594 and then Is_Array_Type (T)
3595 and then Is_Entity_Name (Drange)
3597 if Is_Entity_Name (Original_Node (First_Index (T)))
3598 and then Entity (Original_Node (First_Index (T)))
3601 if Warn_On_Redundant_Constructs then
3602 Error_Msg_N ("redundant slice denotes whole array?r?", N);
3605 -- The following might be a useful optimization???
3607 -- Rewrite (N, New_Occurrence_Of (E, Sloc (N)));
3614 -------------------------
3615 -- Eval_String_Literal --
3616 -------------------------
3618 procedure Eval_String_Literal (N : Node_Id) is
3619 Typ : constant Entity_Id := Etype (N);
3620 Bas : constant Entity_Id := Base_Type (Typ);
3626 -- Nothing to do if error type (handles cases like default expressions
3627 -- or generics where we have not yet fully resolved the type).
3629 if Bas = Any_Type or else Bas = Any_String then
3633 -- String literals are static if the subtype is static (RM 4.9(2)), so
3634 -- reset the static expression flag (it was set unconditionally in
3635 -- Analyze_String_Literal) if the subtype is non-static. We tell if
3636 -- the subtype is static by looking at the lower bound.
3638 if Ekind (Typ) = E_String_Literal_Subtype then
3639 if not Is_OK_Static_Expression (String_Literal_Low_Bound (Typ)) then
3640 Set_Is_Static_Expression (N, False);
3644 -- Here if Etype of string literal is normal Etype (not yet possible,
3645 -- but may be possible in future).
3647 elsif not Is_OK_Static_Expression
3648 (Type_Low_Bound (Etype (First_Index (Typ))))
3650 Set_Is_Static_Expression (N, False);
3654 -- If original node was a type conversion, then result if non-static
3656 if Nkind (Original_Node (N)) = N_Type_Conversion then
3657 Set_Is_Static_Expression (N, False);
3661 -- Test for illegal Ada 95 cases. A string literal is illegal in Ada 95
3662 -- if its bounds are outside the index base type and this index type is
3663 -- static. This can happen in only two ways. Either the string literal
3664 -- is too long, or it is null, and the lower bound is type'First. In
3665 -- either case it is the upper bound that is out of range of the index
3667 if Ada_Version >= Ada_95 then
3668 if Root_Type (Bas) = Standard_String
3670 Root_Type (Bas) = Standard_Wide_String
3672 Root_Type (Bas) = Standard_Wide_Wide_String
3674 Xtp := Standard_Positive;
3676 Xtp := Etype (First_Index (Bas));
3679 if Ekind (Typ) = E_String_Literal_Subtype then
3680 Lo := String_Literal_Low_Bound (Typ);
3682 Lo := Type_Low_Bound (Etype (First_Index (Typ)));
3685 -- Check for string too long
3687 Len := String_Length (Strval (N));
3689 if UI_From_Int (Len) > String_Type_Len (Bas) then
3691 -- Issue message. Note that this message is a warning if the
3692 -- string literal is not marked as static (happens in some cases
3693 -- of folding strings known at compile time, but not static).
3694 -- Furthermore in such cases, we reword the message, since there
3695 -- is no string literal in the source program.
3697 if Is_Static_Expression (N) then
3698 Apply_Compile_Time_Constraint_Error
3699 (N, "string literal too long for}", CE_Length_Check_Failed,
3701 Typ => First_Subtype (Bas));
3703 Apply_Compile_Time_Constraint_Error
3704 (N, "string value too long for}", CE_Length_Check_Failed,
3706 Typ => First_Subtype (Bas),
3710 -- Test for null string not allowed
3713 and then not Is_Generic_Type (Xtp)
3715 Expr_Value (Lo) = Expr_Value (Type_Low_Bound (Base_Type (Xtp)))
3717 -- Same specialization of message
3719 if Is_Static_Expression (N) then
3720 Apply_Compile_Time_Constraint_Error
3721 (N, "null string literal not allowed for}",
3722 CE_Length_Check_Failed,
3724 Typ => First_Subtype (Bas));
3726 Apply_Compile_Time_Constraint_Error
3727 (N, "null string value not allowed for}",
3728 CE_Length_Check_Failed,
3730 Typ => First_Subtype (Bas),
3735 end Eval_String_Literal;
3737 --------------------------
3738 -- Eval_Type_Conversion --
3739 --------------------------
3741 -- A type conversion is potentially static if its subtype mark is for a
3742 -- static scalar subtype, and its operand expression is potentially static
3745 procedure Eval_Type_Conversion (N : Node_Id) is
3746 Operand : constant Node_Id := Expression (N);
3747 Source_Type : constant Entity_Id := Etype (Operand);
3748 Target_Type : constant Entity_Id := Etype (N);
3753 function To_Be_Treated_As_Integer (T : Entity_Id) return Boolean;
3754 -- Returns true if type T is an integer type, or if it is a fixed-point
3755 -- type to be treated as an integer (i.e. the flag Conversion_OK is set
3756 -- on the conversion node).
3758 function To_Be_Treated_As_Real (T : Entity_Id) return Boolean;
3759 -- Returns true if type T is a floating-point type, or if it is a
3760 -- fixed-point type that is not to be treated as an integer (i.e. the
3761 -- flag Conversion_OK is not set on the conversion node).
3763 ------------------------------
3764 -- To_Be_Treated_As_Integer --
3765 ------------------------------
3767 function To_Be_Treated_As_Integer (T : Entity_Id) return Boolean is
3771 or else (Is_Fixed_Point_Type (T) and then Conversion_OK (N));
3772 end To_Be_Treated_As_Integer;
3774 ---------------------------
3775 -- To_Be_Treated_As_Real --
3776 ---------------------------
3778 function To_Be_Treated_As_Real (T : Entity_Id) return Boolean is
3781 Is_Floating_Point_Type (T)
3782 or else (Is_Fixed_Point_Type (T) and then not Conversion_OK (N));
3783 end To_Be_Treated_As_Real;
3785 -- Start of processing for Eval_Type_Conversion
3788 -- Cannot fold if target type is non-static or if semantic error
3790 if not Is_Static_Subtype (Target_Type) then
3791 Check_Non_Static_Context (Operand);
3793 elsif Error_Posted (N) then
3797 -- If not foldable we are done
3799 Test_Expression_Is_Foldable (N, Operand, Stat, Fold);
3804 -- Don't try fold if target type has constraint error bounds
3806 elsif not Is_OK_Static_Subtype (Target_Type) then
3807 Set_Raises_Constraint_Error (N);
3811 -- Remaining processing depends on operand types. Note that in the
3812 -- following type test, fixed-point counts as real unless the flag
3813 -- Conversion_OK is set, in which case it counts as integer.
3815 -- Fold conversion, case of string type. The result is not static
3817 if Is_String_Type (Target_Type) then
3818 Fold_Str (N, Strval (Get_String_Val (Operand)), Static => False);
3821 -- Fold conversion, case of integer target type
3823 elsif To_Be_Treated_As_Integer (Target_Type) then
3828 -- Integer to integer conversion
3830 if To_Be_Treated_As_Integer (Source_Type) then
3831 Result := Expr_Value (Operand);
3833 -- Real to integer conversion
3836 Result := UR_To_Uint (Expr_Value_R (Operand));
3839 -- If fixed-point type (Conversion_OK must be set), then the
3840 -- result is logically an integer, but we must replace the
3841 -- conversion with the corresponding real literal, since the
3842 -- type from a semantic point of view is still fixed-point.
3844 if Is_Fixed_Point_Type (Target_Type) then
3846 (N, UR_From_Uint (Result) * Small_Value (Target_Type), Stat);
3848 -- Otherwise result is integer literal
3851 Fold_Uint (N, Result, Stat);
3855 -- Fold conversion, case of real target type
3857 elsif To_Be_Treated_As_Real (Target_Type) then
3862 if To_Be_Treated_As_Real (Source_Type) then
3863 Result := Expr_Value_R (Operand);
3865 Result := UR_From_Uint (Expr_Value (Operand));
3868 Fold_Ureal (N, Result, Stat);
3871 -- Enumeration types
3874 Fold_Uint (N, Expr_Value (Operand), Stat);
3877 if Is_Out_Of_Range (N, Etype (N), Assume_Valid => True) then
3881 end Eval_Type_Conversion;
3887 -- Predefined unary operators are static functions (RM 4.9(20)) and thus
3888 -- are potentially static if the operand is potentially static (RM 4.9(7)).
3890 procedure Eval_Unary_Op (N : Node_Id) is
3891 Right : constant Node_Id := Right_Opnd (N);
3892 Otype : Entity_Id := Empty;
3897 -- If not foldable we are done
3899 Test_Expression_Is_Foldable (N, Right, Stat, Fold);
3905 if Etype (Right) = Universal_Integer
3907 Etype (Right) = Universal_Real
3909 Otype := Find_Universal_Operator_Type (N);
3912 -- Fold for integer case
3914 if Is_Integer_Type (Etype (N)) then
3916 Rint : constant Uint := Expr_Value (Right);
3920 -- In the case of modular unary plus and abs there is no need
3921 -- to adjust the result of the operation since if the original
3922 -- operand was in bounds the result will be in the bounds of the
3923 -- modular type. However, in the case of modular unary minus the
3924 -- result may go out of the bounds of the modular type and needs
3927 if Nkind (N) = N_Op_Plus then
3930 elsif Nkind (N) = N_Op_Minus then
3931 if Is_Modular_Integer_Type (Etype (N)) then
3932 Result := (-Rint) mod Modulus (Etype (N));
3938 pragma Assert (Nkind (N) = N_Op_Abs);
3942 Fold_Uint (N, Result, Stat);
3945 -- Fold for real case
3947 elsif Is_Real_Type (Etype (N)) then
3949 Rreal : constant Ureal := Expr_Value_R (Right);
3953 if Nkind (N) = N_Op_Plus then
3955 elsif Nkind (N) = N_Op_Minus then
3956 Result := UR_Negate (Rreal);
3958 pragma Assert (Nkind (N) = N_Op_Abs);
3959 Result := abs Rreal;
3962 Fold_Ureal (N, Result, Stat);
3966 -- If the operator was resolved to a specific type, make sure that type
3967 -- is frozen even if the expression is folded into a literal (which has
3968 -- a universal type).
3970 if Present (Otype) then
3971 Freeze_Before (N, Otype);
3975 -------------------------------
3976 -- Eval_Unchecked_Conversion --
3977 -------------------------------
3979 -- Unchecked conversions can never be static, so the only required
3980 -- processing is to check for a non-static context for the operand.
3982 procedure Eval_Unchecked_Conversion (N : Node_Id) is
3984 Check_Non_Static_Context (Expression (N));
3985 end Eval_Unchecked_Conversion;
3987 --------------------
3988 -- Expr_Rep_Value --
3989 --------------------
3991 function Expr_Rep_Value (N : Node_Id) return Uint is
3992 Kind : constant Node_Kind := Nkind (N);
3996 if Is_Entity_Name (N) then
3999 -- An enumeration literal that was either in the source or created
4000 -- as a result of static evaluation.
4002 if Ekind (Ent) = E_Enumeration_Literal then
4003 return Enumeration_Rep (Ent);
4005 -- A user defined static constant
4008 pragma Assert (Ekind (Ent) = E_Constant);
4009 return Expr_Rep_Value (Constant_Value (Ent));
4012 -- An integer literal that was either in the source or created as a
4013 -- result of static evaluation.
4015 elsif Kind = N_Integer_Literal then
4018 -- A real literal for a fixed-point type. This must be the fixed-point
4019 -- case, either the literal is of a fixed-point type, or it is a bound
4020 -- of a fixed-point type, with type universal real. In either case we
4021 -- obtain the desired value from Corresponding_Integer_Value.
4023 elsif Kind = N_Real_Literal then
4024 pragma Assert (Is_Fixed_Point_Type (Underlying_Type (Etype (N))));
4025 return Corresponding_Integer_Value (N);
4027 -- Otherwise must be character literal
4030 pragma Assert (Kind = N_Character_Literal);
4033 -- Since Character literals of type Standard.Character don't have any
4034 -- defining character literals built for them, they do not have their
4035 -- Entity set, so just use their Char code. Otherwise for user-
4036 -- defined character literals use their Pos value as usual which is
4037 -- the same as the Rep value.
4040 return Char_Literal_Value (N);
4042 return Enumeration_Rep (Ent);
4051 function Expr_Value (N : Node_Id) return Uint is
4052 Kind : constant Node_Kind := Nkind (N);
4053 CV_Ent : CV_Entry renames CV_Cache (Nat (N) mod CV_Cache_Size);
4058 -- If already in cache, then we know it's compile time known and we can
4059 -- return the value that was previously stored in the cache since
4060 -- compile time known values cannot change.
4062 if CV_Ent.N = N then
4066 -- Otherwise proceed to test value
4068 if Is_Entity_Name (N) then
4071 -- An enumeration literal that was either in the source or created as
4072 -- a result of static evaluation.
4074 if Ekind (Ent) = E_Enumeration_Literal then
4075 Val := Enumeration_Pos (Ent);
4077 -- A user defined static constant
4080 pragma Assert (Ekind (Ent) = E_Constant);
4081 Val := Expr_Value (Constant_Value (Ent));
4084 -- An integer literal that was either in the source or created as a
4085 -- result of static evaluation.
4087 elsif Kind = N_Integer_Literal then
4090 -- A real literal for a fixed-point type. This must be the fixed-point
4091 -- case, either the literal is of a fixed-point type, or it is a bound
4092 -- of a fixed-point type, with type universal real. In either case we
4093 -- obtain the desired value from Corresponding_Integer_Value.
4095 elsif Kind = N_Real_Literal then
4096 pragma Assert (Is_Fixed_Point_Type (Underlying_Type (Etype (N))));
4097 Val := Corresponding_Integer_Value (N);
4099 -- Otherwise must be character literal
4102 pragma Assert (Kind = N_Character_Literal);
4105 -- Since Character literals of type Standard.Character don't
4106 -- have any defining character literals built for them, they
4107 -- do not have their Entity set, so just use their Char
4108 -- code. Otherwise for user-defined character literals use
4109 -- their Pos value as usual.
4112 Val := Char_Literal_Value (N);
4114 Val := Enumeration_Pos (Ent);
4118 -- Come here with Val set to value to be returned, set cache
4129 function Expr_Value_E (N : Node_Id) return Entity_Id is
4130 Ent : constant Entity_Id := Entity (N);
4132 if Ekind (Ent) = E_Enumeration_Literal then
4135 pragma Assert (Ekind (Ent) = E_Constant);
4136 return Expr_Value_E (Constant_Value (Ent));
4144 function Expr_Value_R (N : Node_Id) return Ureal is
4145 Kind : constant Node_Kind := Nkind (N);
4149 if Kind = N_Real_Literal then
4152 elsif Kind = N_Identifier or else Kind = N_Expanded_Name then
4154 pragma Assert (Ekind (Ent) = E_Constant);
4155 return Expr_Value_R (Constant_Value (Ent));
4157 elsif Kind = N_Integer_Literal then
4158 return UR_From_Uint (Expr_Value (N));
4160 -- Here, we have a node that cannot be interpreted as a compile time
4161 -- constant. That is definitely an error.
4164 raise Program_Error;
4172 function Expr_Value_S (N : Node_Id) return Node_Id is
4174 if Nkind (N) = N_String_Literal then
4177 pragma Assert (Ekind (Entity (N)) = E_Constant);
4178 return Expr_Value_S (Constant_Value (Entity (N)));
4182 ----------------------------------
4183 -- Find_Universal_Operator_Type --
4184 ----------------------------------
4186 function Find_Universal_Operator_Type (N : Node_Id) return Entity_Id is
4187 PN : constant Node_Id := Parent (N);
4188 Call : constant Node_Id := Original_Node (N);
4189 Is_Int : constant Boolean := Is_Integer_Type (Etype (N));
4191 Is_Fix : constant Boolean :=
4192 Nkind (N) in N_Binary_Op
4193 and then Nkind (Right_Opnd (N)) /= Nkind (Left_Opnd (N));
4194 -- A mixed-mode operation in this context indicates the presence of
4195 -- fixed-point type in the designated package.
4197 Is_Relational : constant Boolean := Etype (N) = Standard_Boolean;
4198 -- Case where N is a relational (or membership) operator (else it is an
4201 In_Membership : constant Boolean :=
4202 Nkind (PN) in N_Membership_Test
4204 Nkind (Right_Opnd (PN)) = N_Range
4206 Is_Universal_Numeric_Type (Etype (Left_Opnd (PN)))
4208 Is_Universal_Numeric_Type
4209 (Etype (Low_Bound (Right_Opnd (PN))))
4211 Is_Universal_Numeric_Type
4212 (Etype (High_Bound (Right_Opnd (PN))));
4213 -- Case where N is part of a membership test with a universal range
4217 Typ1 : Entity_Id := Empty;
4220 function Is_Mixed_Mode_Operand (Op : Node_Id) return Boolean;
4221 -- Check whether one operand is a mixed-mode operation that requires the
4222 -- presence of a fixed-point type. Given that all operands are universal
4223 -- and have been constant-folded, retrieve the original function call.
4225 ---------------------------
4226 -- Is_Mixed_Mode_Operand --
4227 ---------------------------
4229 function Is_Mixed_Mode_Operand (Op : Node_Id) return Boolean is
4230 Onod : constant Node_Id := Original_Node (Op);
4232 return Nkind (Onod) = N_Function_Call
4233 and then Present (Next_Actual (First_Actual (Onod)))
4234 and then Etype (First_Actual (Onod)) /=
4235 Etype (Next_Actual (First_Actual (Onod)));
4236 end Is_Mixed_Mode_Operand;
4238 -- Start of processing for Find_Universal_Operator_Type
4241 if Nkind (Call) /= N_Function_Call
4242 or else Nkind (Name (Call)) /= N_Expanded_Name
4246 -- There are several cases where the context does not imply the type of
4248 -- - the universal expression appears in a type conversion;
4249 -- - the expression is a relational operator applied to universal
4251 -- - the expression is a membership test with a universal operand
4252 -- and a range with universal bounds.
4254 elsif Nkind (Parent (N)) = N_Type_Conversion
4255 or else Is_Relational
4256 or else In_Membership
4258 Pack := Entity (Prefix (Name (Call)));
4260 -- If the prefix is a package declared elsewhere, iterate over its
4261 -- visible entities, otherwise iterate over all declarations in the
4262 -- designated scope.
4264 if Ekind (Pack) = E_Package
4265 and then not In_Open_Scopes (Pack)
4267 Priv_E := First_Private_Entity (Pack);
4273 E := First_Entity (Pack);
4274 while Present (E) and then E /= Priv_E loop
4275 if Is_Numeric_Type (E)
4276 and then Nkind (Parent (E)) /= N_Subtype_Declaration
4277 and then Comes_From_Source (E)
4278 and then Is_Integer_Type (E) = Is_Int
4279 and then (Nkind (N) in N_Unary_Op
4280 or else Is_Relational
4281 or else Is_Fixed_Point_Type (E) = Is_Fix)
4286 -- Before emitting an error, check for the presence of a
4287 -- mixed-mode operation that specifies a fixed point type.
4291 (Is_Mixed_Mode_Operand (Left_Opnd (N))
4292 or else Is_Mixed_Mode_Operand (Right_Opnd (N)))
4293 and then Is_Fixed_Point_Type (E) /= Is_Fixed_Point_Type (Typ1)
4296 if Is_Fixed_Point_Type (E) then
4301 -- More than one type of the proper class declared in P
4303 Error_Msg_N ("ambiguous operation", N);
4304 Error_Msg_Sloc := Sloc (Typ1);
4305 Error_Msg_N ("\possible interpretation (inherited)#", N);
4306 Error_Msg_Sloc := Sloc (E);
4307 Error_Msg_N ("\possible interpretation (inherited)#", N);
4317 end Find_Universal_Operator_Type;
4319 --------------------------
4320 -- Flag_Non_Static_Expr --
4321 --------------------------
4323 procedure Flag_Non_Static_Expr (Msg : String; Expr : Node_Id) is
4325 if Error_Posted (Expr) and then not All_Errors_Mode then
4328 Error_Msg_F (Msg, Expr);
4329 Why_Not_Static (Expr);
4331 end Flag_Non_Static_Expr;
4337 procedure Fold_Str (N : Node_Id; Val : String_Id; Static : Boolean) is
4338 Loc : constant Source_Ptr := Sloc (N);
4339 Typ : constant Entity_Id := Etype (N);
4342 if Raises_Constraint_Error (N) then
4343 Set_Is_Static_Expression (N, Static);
4347 Rewrite (N, Make_String_Literal (Loc, Strval => Val));
4349 -- We now have the literal with the right value, both the actual type
4350 -- and the expected type of this literal are taken from the expression
4351 -- that was evaluated. So now we do the Analyze and Resolve.
4353 -- Note that we have to reset Is_Static_Expression both after the
4354 -- analyze step (because Resolve will evaluate the literal, which
4355 -- will cause semantic errors if it is marked as static), and after
4356 -- the Resolve step (since Resolve in some cases resets this flag).
4359 Set_Is_Static_Expression (N, Static);
4362 Set_Is_Static_Expression (N, Static);
4369 procedure Fold_Uint (N : Node_Id; Val : Uint; Static : Boolean) is
4370 Loc : constant Source_Ptr := Sloc (N);
4371 Typ : Entity_Id := Etype (N);
4375 if Raises_Constraint_Error (N) then
4376 Set_Is_Static_Expression (N, Static);
4380 -- If we are folding a named number, retain the entity in the literal,
4383 if Is_Entity_Name (N) and then Ekind (Entity (N)) = E_Named_Integer then
4389 if Is_Private_Type (Typ) then
4390 Typ := Full_View (Typ);
4393 -- For a result of type integer, substitute an N_Integer_Literal node
4394 -- for the result of the compile time evaluation of the expression.
4395 -- For ASIS use, set a link to the original named number when not in
4396 -- a generic context.
4398 if Is_Integer_Type (Typ) then
4399 Rewrite (N, Make_Integer_Literal (Loc, Val));
4400 Set_Original_Entity (N, Ent);
4402 -- Otherwise we have an enumeration type, and we substitute either
4403 -- an N_Identifier or N_Character_Literal to represent the enumeration
4404 -- literal corresponding to the given value, which must always be in
4405 -- range, because appropriate tests have already been made for this.
4407 else pragma Assert (Is_Enumeration_Type (Typ));
4408 Rewrite (N, Get_Enum_Lit_From_Pos (Etype (N), Val, Loc));
4411 -- We now have the literal with the right value, both the actual type
4412 -- and the expected type of this literal are taken from the expression
4413 -- that was evaluated. So now we do the Analyze and Resolve.
4415 -- Note that we have to reset Is_Static_Expression both after the
4416 -- analyze step (because Resolve will evaluate the literal, which
4417 -- will cause semantic errors if it is marked as static), and after
4418 -- the Resolve step (since Resolve in some cases sets this flag).
4421 Set_Is_Static_Expression (N, Static);
4424 Set_Is_Static_Expression (N, Static);
4431 procedure Fold_Ureal (N : Node_Id; Val : Ureal; Static : Boolean) is
4432 Loc : constant Source_Ptr := Sloc (N);
4433 Typ : constant Entity_Id := Etype (N);
4437 if Raises_Constraint_Error (N) then
4438 Set_Is_Static_Expression (N, Static);
4442 -- If we are folding a named number, retain the entity in the literal,
4445 if Is_Entity_Name (N) and then Ekind (Entity (N)) = E_Named_Real then
4451 Rewrite (N, Make_Real_Literal (Loc, Realval => Val));
4453 -- Set link to original named number, for ASIS use
4455 Set_Original_Entity (N, Ent);
4457 -- We now have the literal with the right value, both the actual type
4458 -- and the expected type of this literal are taken from the expression
4459 -- that was evaluated. So now we do the Analyze and Resolve.
4461 -- Note that we have to reset Is_Static_Expression both after the
4462 -- analyze step (because Resolve will evaluate the literal, which
4463 -- will cause semantic errors if it is marked as static), and after
4464 -- the Resolve step (since Resolve in some cases sets this flag).
4467 Set_Is_Static_Expression (N, Static);
4470 Set_Is_Static_Expression (N, Static);
4477 function From_Bits (B : Bits; T : Entity_Id) return Uint is
4481 for J in 0 .. B'Last loop
4487 if Non_Binary_Modulus (T) then
4488 V := V mod Modulus (T);
4494 --------------------
4495 -- Get_String_Val --
4496 --------------------
4498 function Get_String_Val (N : Node_Id) return Node_Id is
4500 if Nkind_In (N, N_String_Literal, N_Character_Literal) then
4503 pragma Assert (Is_Entity_Name (N));
4504 return Get_String_Val (Constant_Value (Entity (N)));
4512 procedure Initialize is
4514 CV_Cache := (others => (Node_High_Bound, Uint_0));
4517 --------------------
4518 -- In_Subrange_Of --
4519 --------------------
4521 function In_Subrange_Of
4524 Fixed_Int : Boolean := False) return Boolean
4533 if T1 = T2 or else Is_Subtype_Of (T1, T2) then
4536 -- Never in range if both types are not scalar. Don't know if this can
4537 -- actually happen, but just in case.
4539 elsif not Is_Scalar_Type (T1) or else not Is_Scalar_Type (T2) then
4542 -- If T1 has infinities but T2 doesn't have infinities, then T1 is
4543 -- definitely not compatible with T2.
4545 elsif Is_Floating_Point_Type (T1)
4546 and then Has_Infinities (T1)
4547 and then Is_Floating_Point_Type (T2)
4548 and then not Has_Infinities (T2)
4553 L1 := Type_Low_Bound (T1);
4554 H1 := Type_High_Bound (T1);
4556 L2 := Type_Low_Bound (T2);
4557 H2 := Type_High_Bound (T2);
4559 -- Check bounds to see if comparison possible at compile time
4561 if Compile_Time_Compare (L1, L2, Assume_Valid => True) in Compare_GE
4563 Compile_Time_Compare (H1, H2, Assume_Valid => True) in Compare_LE
4568 -- If bounds not comparable at compile time, then the bounds of T2
4569 -- must be compile time known or we cannot answer the query.
4571 if not Compile_Time_Known_Value (L2)
4572 or else not Compile_Time_Known_Value (H2)
4577 -- If the bounds of T1 are know at compile time then use these
4578 -- ones, otherwise use the bounds of the base type (which are of
4579 -- course always static).
4581 if not Compile_Time_Known_Value (L1) then
4582 L1 := Type_Low_Bound (Base_Type (T1));
4585 if not Compile_Time_Known_Value (H1) then
4586 H1 := Type_High_Bound (Base_Type (T1));
4589 -- Fixed point types should be considered as such only if
4590 -- flag Fixed_Int is set to False.
4592 if Is_Floating_Point_Type (T1) or else Is_Floating_Point_Type (T2)
4593 or else (Is_Fixed_Point_Type (T1) and then not Fixed_Int)
4594 or else (Is_Fixed_Point_Type (T2) and then not Fixed_Int)
4597 Expr_Value_R (L2) <= Expr_Value_R (L1)
4599 Expr_Value_R (H2) >= Expr_Value_R (H1);
4603 Expr_Value (L2) <= Expr_Value (L1)
4605 Expr_Value (H2) >= Expr_Value (H1);
4610 -- If any exception occurs, it means that we have some bug in the compiler
4611 -- possibly triggered by a previous error, or by some unforeseen peculiar
4612 -- occurrence. However, this is only an optimization attempt, so there is
4613 -- really no point in crashing the compiler. Instead we just decide, too
4614 -- bad, we can't figure out the answer in this case after all.
4619 -- Debug flag K disables this behavior (useful for debugging)
4621 if Debug_Flag_K then
4632 function Is_In_Range
4635 Assume_Valid : Boolean := False;
4636 Fixed_Int : Boolean := False;
4637 Int_Real : Boolean := False) return Boolean
4641 Test_In_Range (N, Typ, Assume_Valid, Fixed_Int, Int_Real) = In_Range;
4648 function Is_Null_Range (Lo : Node_Id; Hi : Node_Id) return Boolean is
4649 Typ : constant Entity_Id := Etype (Lo);
4652 if not Compile_Time_Known_Value (Lo)
4653 or else not Compile_Time_Known_Value (Hi)
4658 if Is_Discrete_Type (Typ) then
4659 return Expr_Value (Lo) > Expr_Value (Hi);
4660 else pragma Assert (Is_Real_Type (Typ));
4661 return Expr_Value_R (Lo) > Expr_Value_R (Hi);
4665 -------------------------
4666 -- Is_OK_Static_Choice --
4667 -------------------------
4669 function Is_OK_Static_Choice (Choice : Node_Id) return Boolean is
4671 -- Check various possibilities for choice
4673 -- Note: for membership tests, we test more cases than are possible
4674 -- (in particular subtype indication), but it doesn't matter because
4675 -- it just won't occur (we have already done a syntax check).
4677 if Nkind (Choice) = N_Others_Choice then
4680 elsif Nkind (Choice) = N_Range then
4681 return Is_OK_Static_Range (Choice);
4683 elsif Nkind (Choice) = N_Subtype_Indication
4685 (Is_Entity_Name (Choice) and then Is_Type (Entity (Choice)))
4687 return Is_OK_Static_Subtype (Etype (Choice));
4690 return Is_OK_Static_Expression (Choice);
4692 end Is_OK_Static_Choice;
4694 ------------------------------
4695 -- Is_OK_Static_Choice_List --
4696 ------------------------------
4698 function Is_OK_Static_Choice_List (Choices : List_Id) return Boolean is
4702 if not Is_Static_Choice_List (Choices) then
4706 Choice := First (Choices);
4707 while Present (Choice) loop
4708 if not Is_OK_Static_Choice (Choice) then
4709 Set_Raises_Constraint_Error (Choice);
4717 end Is_OK_Static_Choice_List;
4719 -----------------------------
4720 -- Is_OK_Static_Expression --
4721 -----------------------------
4723 function Is_OK_Static_Expression (N : Node_Id) return Boolean is
4725 return Is_Static_Expression (N) and then not Raises_Constraint_Error (N);
4726 end Is_OK_Static_Expression;
4728 ------------------------
4729 -- Is_OK_Static_Range --
4730 ------------------------
4732 -- A static range is a range whose bounds are static expressions, or a
4733 -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)).
4734 -- We have already converted range attribute references, so we get the
4735 -- "or" part of this rule without needing a special test.
4737 function Is_OK_Static_Range (N : Node_Id) return Boolean is
4739 return Is_OK_Static_Expression (Low_Bound (N))
4740 and then Is_OK_Static_Expression (High_Bound (N));
4741 end Is_OK_Static_Range;
4743 --------------------------
4744 -- Is_OK_Static_Subtype --
4745 --------------------------
4747 -- Determines if Typ is a static subtype as defined in (RM 4.9(26)) where
4748 -- neither bound raises constraint error when evaluated.
4750 function Is_OK_Static_Subtype (Typ : Entity_Id) return Boolean is
4751 Base_T : constant Entity_Id := Base_Type (Typ);
4752 Anc_Subt : Entity_Id;
4755 -- First a quick check on the non static subtype flag. As described
4756 -- in further detail in Einfo, this flag is not decisive in all cases,
4757 -- but if it is set, then the subtype is definitely non-static.
4759 if Is_Non_Static_Subtype (Typ) then
4763 Anc_Subt := Ancestor_Subtype (Typ);
4765 if Anc_Subt = Empty then
4769 if Is_Generic_Type (Root_Type (Base_T))
4770 or else Is_Generic_Actual_Type (Base_T)
4776 elsif Is_String_Type (Typ) then
4778 Ekind (Typ) = E_String_Literal_Subtype
4780 (Is_OK_Static_Subtype (Component_Type (Typ))
4781 and then Is_OK_Static_Subtype (Etype (First_Index (Typ))));
4785 elsif Is_Scalar_Type (Typ) then
4786 if Base_T = Typ then
4790 -- Scalar_Range (Typ) might be an N_Subtype_Indication, so use
4791 -- Get_Type_{Low,High}_Bound.
4793 return Is_OK_Static_Subtype (Anc_Subt)
4794 and then Is_OK_Static_Expression (Type_Low_Bound (Typ))
4795 and then Is_OK_Static_Expression (Type_High_Bound (Typ));
4798 -- Types other than string and scalar types are never static
4803 end Is_OK_Static_Subtype;
4805 ---------------------
4806 -- Is_Out_Of_Range --
4807 ---------------------
4809 function Is_Out_Of_Range
4812 Assume_Valid : Boolean := False;
4813 Fixed_Int : Boolean := False;
4814 Int_Real : Boolean := False) return Boolean
4817 return Test_In_Range (N, Typ, Assume_Valid, Fixed_Int, Int_Real) =
4819 end Is_Out_Of_Range;
4821 ----------------------
4822 -- Is_Static_Choice --
4823 ----------------------
4825 function Is_Static_Choice (Choice : Node_Id) return Boolean is
4827 -- Check various possibilities for choice
4829 -- Note: for membership tests, we test more cases than are possible
4830 -- (in particular subtype indication), but it doesn't matter because
4831 -- it just won't occur (we have already done a syntax check).
4833 if Nkind (Choice) = N_Others_Choice then
4836 elsif Nkind (Choice) = N_Range then
4837 return Is_Static_Range (Choice);
4839 elsif Nkind (Choice) = N_Subtype_Indication
4841 (Is_Entity_Name (Choice) and then Is_Type (Entity (Choice)))
4843 return Is_Static_Subtype (Etype (Choice));
4846 return Is_Static_Expression (Choice);
4848 end Is_Static_Choice;
4850 ---------------------------
4851 -- Is_Static_Choice_List --
4852 ---------------------------
4854 function Is_Static_Choice_List (Choices : List_Id) return Boolean is
4858 Choice := First (Choices);
4859 while Present (Choice) loop
4860 if not Is_Static_Choice (Choice) then
4868 end Is_Static_Choice_List;
4870 ---------------------
4871 -- Is_Static_Range --
4872 ---------------------
4874 -- A static range is a range whose bounds are static expressions, or a
4875 -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)).
4876 -- We have already converted range attribute references, so we get the
4877 -- "or" part of this rule without needing a special test.
4879 function Is_Static_Range (N : Node_Id) return Boolean is
4881 return Is_Static_Expression (Low_Bound (N))
4883 Is_Static_Expression (High_Bound (N));
4884 end Is_Static_Range;
4886 -----------------------
4887 -- Is_Static_Subtype --
4888 -----------------------
4890 -- Determines if Typ is a static subtype as defined in (RM 4.9(26))
4892 function Is_Static_Subtype (Typ : Entity_Id) return Boolean is
4893 Base_T : constant Entity_Id := Base_Type (Typ);
4894 Anc_Subt : Entity_Id;
4897 -- First a quick check on the non static subtype flag. As described
4898 -- in further detail in Einfo, this flag is not decisive in all cases,
4899 -- but if it is set, then the subtype is definitely non-static.
4901 if Is_Non_Static_Subtype (Typ) then
4905 Anc_Subt := Ancestor_Subtype (Typ);
4907 if Anc_Subt = Empty then
4911 if Is_Generic_Type (Root_Type (Base_T))
4912 or else Is_Generic_Actual_Type (Base_T)
4918 elsif Is_String_Type (Typ) then
4920 Ekind (Typ) = E_String_Literal_Subtype
4921 or else (Is_Static_Subtype (Component_Type (Typ))
4922 and then Is_Static_Subtype (Etype (First_Index (Typ))));
4926 elsif Is_Scalar_Type (Typ) then
4927 if Base_T = Typ then
4931 return Is_Static_Subtype (Anc_Subt)
4932 and then Is_Static_Expression (Type_Low_Bound (Typ))
4933 and then Is_Static_Expression (Type_High_Bound (Typ));
4936 -- Types other than string and scalar types are never static
4941 end Is_Static_Subtype;
4943 -------------------------------
4944 -- Is_Statically_Unevaluated --
4945 -------------------------------
4947 function Is_Statically_Unevaluated (Expr : Node_Id) return Boolean is
4948 function Check_Case_Expr_Alternative
4949 (CEA : Node_Id) return Match_Result;
4950 -- We have a message emanating from the Expression of a case expression
4951 -- alternative. We examine this alternative, as follows:
4953 -- If the selecting expression of the parent case is non-static, or
4954 -- if any of the discrete choices of the given case alternative are
4955 -- non-static or raise Constraint_Error, return Non_Static.
4957 -- Otherwise check if the selecting expression matches any of the given
4958 -- discrete choices. If so, the alternative is executed and we return
4959 -- Match, otherwise, the alternative can never be executed, and so we
4962 ---------------------------------
4963 -- Check_Case_Expr_Alternative --
4964 ---------------------------------
4966 function Check_Case_Expr_Alternative
4967 (CEA : Node_Id) return Match_Result
4969 Case_Exp : constant Node_Id := Parent (CEA);
4974 pragma Assert (Nkind (Case_Exp) = N_Case_Expression);
4976 -- Check that selecting expression is static
4978 if not Is_OK_Static_Expression (Expression (Case_Exp)) then
4982 if not Is_OK_Static_Choice_List (Discrete_Choices (CEA)) then
4986 -- All choices are now known to be static. Now see if alternative
4987 -- matches one of the choices.
4989 Choice := First (Discrete_Choices (CEA));
4990 while Present (Choice) loop
4992 -- Check various possibilities for choice, returning Match if we
4993 -- find the selecting value matches any of the choices. Note that
4994 -- we know we are the last choice, so we don't have to keep going.
4996 if Nkind (Choice) = N_Others_Choice then
4998 -- Others choice is a bit annoying, it matches if none of the
4999 -- previous alternatives matches (note that we know we are the
5000 -- last alternative in this case, so we can just go backwards
5001 -- from us to see if any previous one matches).
5003 Prev_CEA := Prev (CEA);
5004 while Present (Prev_CEA) loop
5005 if Check_Case_Expr_Alternative (Prev_CEA) = Match then
5014 -- Else we have a normal static choice
5016 elsif Choice_Matches (Expression (Case_Exp), Choice) = Match then
5020 -- If we fall through, it means that the discrete choice did not
5021 -- match the selecting expression, so continue.
5026 -- If we get through that loop then all choices were static, and none
5027 -- of them matched the selecting expression. So return No_Match.
5030 end Check_Case_Expr_Alternative;
5038 -- Start of processing for Is_Statically_Unevaluated
5041 -- The (32.x) references here are from RM section 4.9
5043 -- (32.1) An expression is statically unevaluated if it is part of ...
5045 -- This means we have to climb the tree looking for one of the cases
5052 -- (32.2) The right operand of a static short-circuit control form
5053 -- whose value is determined by its left operand.
5055 -- AND THEN with False as left operand
5057 if Nkind (P) = N_And_Then
5058 and then Compile_Time_Known_Value (Left_Opnd (P))
5059 and then Is_False (Expr_Value (Left_Opnd (P)))
5063 -- OR ELSE with True as left operand
5065 elsif Nkind (P) = N_Or_Else
5066 and then Compile_Time_Known_Value (Left_Opnd (P))
5067 and then Is_True (Expr_Value (Left_Opnd (P)))
5071 -- (32.3) A dependent_expression of an if_expression whose associated
5072 -- condition is static and equals False.
5074 elsif Nkind (P) = N_If_Expression then
5076 Cond : constant Node_Id := First (Expressions (P));
5077 Texp : constant Node_Id := Next (Cond);
5078 Fexp : constant Node_Id := Next (Texp);
5081 if Compile_Time_Known_Value (Cond) then
5083 -- Condition is True and we are in the right operand
5085 if Is_True (Expr_Value (Cond)) and then OldP = Fexp then
5088 -- Condition is False and we are in the left operand
5090 elsif Is_False (Expr_Value (Cond)) and then OldP = Texp then
5096 -- (32.4) A condition or dependent_expression of an if_expression
5097 -- where the condition corresponding to at least one preceding
5098 -- dependent_expression of the if_expression is static and equals
5101 -- This refers to cases like
5103 -- (if True then 1 elsif 1/0=2 then 2 else 3)
5105 -- But we expand elsif's out anyway, so the above looks like:
5107 -- (if True then 1 else (if 1/0=2 then 2 else 3))
5109 -- So for us this is caught by the above check for the 32.3 case.
5111 -- (32.5) A dependent_expression of a case_expression whose
5112 -- selecting_expression is static and whose value is not covered
5113 -- by the corresponding discrete_choice_list.
5115 elsif Nkind (P) = N_Case_Expression_Alternative then
5117 -- First, we have to be in the expression to suppress messages.
5118 -- If we are within one of the choices, we want the message.
5120 if OldP = Expression (P) then
5122 -- Statically unevaluated if alternative does not match
5124 if Check_Case_Expr_Alternative (P) = No_Match then
5129 -- (32.6) A choice_expression (or a simple_expression of a range
5130 -- that occurs as a membership_choice of a membership_choice_list)
5131 -- of a static membership test that is preceded in the enclosing
5132 -- membership_choice_list by another item whose individual
5133 -- membership test (see (RM 4.5.2)) statically yields True.
5135 elsif Nkind (P) in N_Membership_Test then
5137 -- Only possibly unevaluated if simple expression is static
5139 if not Is_OK_Static_Expression (Left_Opnd (P)) then
5142 -- All members of the choice list must be static
5144 elsif (Present (Right_Opnd (P))
5145 and then not Is_OK_Static_Choice (Right_Opnd (P)))
5146 or else (Present (Alternatives (P))
5148 not Is_OK_Static_Choice_List (Alternatives (P)))
5152 -- If expression is the one and only alternative, then it is
5153 -- definitely not statically unevaluated, so we only have to
5154 -- test the case where there are alternatives present.
5156 elsif Present (Alternatives (P)) then
5158 -- Look for previous matching Choice
5160 Choice := First (Alternatives (P));
5161 while Present (Choice) loop
5163 -- If we reached us and no previous choices matched, this
5164 -- is not the case where we are statically unevaluated.
5166 exit when OldP = Choice;
5168 -- If a previous choice matches, then that is the case where
5169 -- we know our choice is statically unevaluated.
5171 if Choice_Matches (Left_Opnd (P), Choice) = Match then
5178 -- If we fall through the loop, we were not one of the choices,
5179 -- we must have been the expression, so that is not covered by
5180 -- this rule, and we keep going.
5186 -- OK, not statically unevaluated at this level, see if we should
5187 -- keep climbing to look for a higher level reason.
5189 -- Special case for component association in aggregates, where
5190 -- we want to keep climbing up to the parent aggregate.
5192 if Nkind (P) = N_Component_Association
5193 and then Nkind (Parent (P)) = N_Aggregate
5197 -- All done if not still within subexpression
5200 exit when Nkind (P) not in N_Subexpr;
5204 -- If we fall through the loop, not one of the cases covered!
5207 end Is_Statically_Unevaluated;
5209 --------------------
5210 -- Not_Null_Range --
5211 --------------------
5213 function Not_Null_Range (Lo : Node_Id; Hi : Node_Id) return Boolean is
5214 Typ : constant Entity_Id := Etype (Lo);
5217 if not Compile_Time_Known_Value (Lo)
5218 or else not Compile_Time_Known_Value (Hi)
5223 if Is_Discrete_Type (Typ) then
5224 return Expr_Value (Lo) <= Expr_Value (Hi);
5225 else pragma Assert (Is_Real_Type (Typ));
5226 return Expr_Value_R (Lo) <= Expr_Value_R (Hi);
5234 function OK_Bits (N : Node_Id; Bits : Uint) return Boolean is
5236 -- We allow a maximum of 500,000 bits which seems a reasonable limit
5238 if Bits < 500_000 then
5241 -- Error if this maximum is exceeded
5244 Error_Msg_N ("static value too large, capacity exceeded", N);
5253 procedure Out_Of_Range (N : Node_Id) is
5255 -- If we have the static expression case, then this is an illegality
5256 -- in Ada 95 mode, except that in an instance, we never generate an
5257 -- error (if the error is legitimate, it was already diagnosed in the
5260 if Is_Static_Expression (N)
5261 and then not In_Instance
5262 and then not In_Inlined_Body
5263 and then Ada_Version >= Ada_95
5265 -- No message if we are statically unevaluated
5267 if Is_Statically_Unevaluated (N) then
5270 -- The expression to compute the length of a packed array is attached
5271 -- to the array type itself, and deserves a separate message.
5273 elsif Nkind (Parent (N)) = N_Defining_Identifier
5274 and then Is_Array_Type (Parent (N))
5275 and then Present (Packed_Array_Impl_Type (Parent (N)))
5276 and then Present (First_Rep_Item (Parent (N)))
5279 ("length of packed array must not exceed Integer''Last",
5280 First_Rep_Item (Parent (N)));
5281 Rewrite (N, Make_Integer_Literal (Sloc (N), Uint_1));
5283 -- All cases except the special array case
5286 Apply_Compile_Time_Constraint_Error
5287 (N, "value not in range of}", CE_Range_Check_Failed);
5290 -- Here we generate a warning for the Ada 83 case, or when we are in an
5291 -- instance, or when we have a non-static expression case.
5294 Apply_Compile_Time_Constraint_Error
5295 (N, "value not in range of}??", CE_Range_Check_Failed);
5299 ----------------------
5300 -- Predicates_Match --
5301 ----------------------
5303 function Predicates_Match (T1, T2 : Entity_Id) return Boolean is
5308 if Ada_Version < Ada_2012 then
5311 -- Both types must have predicates or lack them
5313 elsif Has_Predicates (T1) /= Has_Predicates (T2) then
5316 -- Check matching predicates
5321 (T1, Name_Static_Predicate, Check_Parents => False);
5324 (T2, Name_Static_Predicate, Check_Parents => False);
5326 -- Subtypes statically match if the predicate comes from the
5327 -- same declaration, which can only happen if one is a subtype
5328 -- of the other and has no explicit predicate.
5330 -- Suppress warnings on order of actuals, which is otherwise
5331 -- triggered by one of the two calls below.
5333 pragma Warnings (Off);
5334 return Pred1 = Pred2
5335 or else (No (Pred1) and then Is_Subtype_Of (T1, T2))
5336 or else (No (Pred2) and then Is_Subtype_Of (T2, T1));
5337 pragma Warnings (On);
5339 end Predicates_Match;
5341 ---------------------------------------------
5342 -- Real_Or_String_Static_Predicate_Matches --
5343 ---------------------------------------------
5345 function Real_Or_String_Static_Predicate_Matches
5347 Typ : Entity_Id) return Boolean
5349 Expr : constant Node_Id := Static_Real_Or_String_Predicate (Typ);
5350 -- The predicate expression from the type
5352 Pfun : constant Entity_Id := Predicate_Function (Typ);
5353 -- The entity for the predicate function
5355 Ent_Name : constant Name_Id := Chars (First_Formal (Pfun));
5356 -- The name of the formal of the predicate function. Occurrences of the
5357 -- type name in Expr have been rewritten as references to this formal,
5358 -- and it has a unique name, so we can identify references by this name.
5361 -- Copy of the predicate function tree
5363 function Process (N : Node_Id) return Traverse_Result;
5364 -- Function used to process nodes during the traversal in which we will
5365 -- find occurrences of the entity name, and replace such occurrences
5366 -- by a real literal with the value to be tested.
5368 procedure Traverse is new Traverse_Proc (Process);
5369 -- The actual traversal procedure
5375 function Process (N : Node_Id) return Traverse_Result is
5377 if Nkind (N) = N_Identifier and then Chars (N) = Ent_Name then
5379 Nod : constant Node_Id := New_Copy (Val);
5381 Set_Sloc (Nod, Sloc (N));
5391 -- Start of processing for Real_Or_String_Static_Predicate_Matches
5394 -- First deal with special case of inherited predicate, where the
5395 -- predicate expression looks like:
5397 -- Expr and then xxPredicate (typ (Ent))
5399 -- where Expr is the predicate expression for this level, and the
5400 -- right operand is the call to evaluate the inherited predicate.
5402 if Nkind (Expr) = N_And_Then
5403 and then Nkind (Right_Opnd (Expr)) = N_Function_Call
5405 -- OK we have the inherited case, so make a call to evaluate the
5406 -- inherited predicate. If that fails, so do we!
5409 Real_Or_String_Static_Predicate_Matches
5411 Typ => Etype (First_Formal (Entity (Name (Right_Opnd (Expr))))))
5416 -- Use the left operand for the continued processing
5418 Copy := Copy_Separate_Tree (Left_Opnd (Expr));
5420 -- Case where call to predicate function appears on its own
5422 elsif Nkind (Expr) = N_Function_Call then
5424 -- Here the result is just the result of calling the inner predicate
5427 Real_Or_String_Static_Predicate_Matches
5429 Typ => Etype (First_Formal (Entity (Name (Expr)))));
5431 -- If no inherited predicate, copy whole expression
5434 Copy := Copy_Separate_Tree (Expr);
5437 -- Now we replace occurrences of the entity by the value
5441 -- And analyze the resulting static expression to see if it is True
5443 Analyze_And_Resolve (Copy, Standard_Boolean);
5444 return Is_True (Expr_Value (Copy));
5445 end Real_Or_String_Static_Predicate_Matches;
5447 -------------------------
5448 -- Rewrite_In_Raise_CE --
5449 -------------------------
5451 procedure Rewrite_In_Raise_CE (N : Node_Id; Exp : Node_Id) is
5452 Typ : constant Entity_Id := Etype (N);
5453 Stat : constant Boolean := Is_Static_Expression (N);
5456 -- If we want to raise CE in the condition of a N_Raise_CE node, we
5457 -- can just clear the condition if the reason is appropriate. We do
5458 -- not do this operation if the parent has a reason other than range
5459 -- check failed, because otherwise we would change the reason.
5461 if Present (Parent (N))
5462 and then Nkind (Parent (N)) = N_Raise_Constraint_Error
5463 and then Reason (Parent (N)) =
5464 UI_From_Int (RT_Exception_Code'Pos (CE_Range_Check_Failed))
5466 Set_Condition (Parent (N), Empty);
5468 -- Else build an explicit N_Raise_CE
5472 Make_Raise_Constraint_Error (Sloc (Exp),
5473 Reason => CE_Range_Check_Failed));
5474 Set_Raises_Constraint_Error (N);
5478 -- Set proper flags in result
5480 Set_Raises_Constraint_Error (N, True);
5481 Set_Is_Static_Expression (N, Stat);
5482 end Rewrite_In_Raise_CE;
5484 ---------------------
5485 -- String_Type_Len --
5486 ---------------------
5488 function String_Type_Len (Stype : Entity_Id) return Uint is
5489 NT : constant Entity_Id := Etype (First_Index (Stype));
5493 if Is_OK_Static_Subtype (NT) then
5496 T := Base_Type (NT);
5499 return Expr_Value (Type_High_Bound (T)) -
5500 Expr_Value (Type_Low_Bound (T)) + 1;
5501 end String_Type_Len;
5503 ------------------------------------
5504 -- Subtypes_Statically_Compatible --
5505 ------------------------------------
5507 function Subtypes_Statically_Compatible
5510 Formal_Derived_Matching : Boolean := False) return Boolean
5515 if Is_Scalar_Type (T1) then
5517 -- Definitely compatible if we match
5519 if Subtypes_Statically_Match (T1, T2) then
5522 -- If either subtype is nonstatic then they're not compatible
5524 elsif not Is_OK_Static_Subtype (T1)
5526 not Is_OK_Static_Subtype (T2)
5530 -- If either type has constraint error bounds, then consider that
5531 -- they match to avoid junk cascaded errors here.
5533 elsif not Is_OK_Static_Subtype (T1)
5534 or else not Is_OK_Static_Subtype (T2)
5538 -- Base types must match, but we don't check that (should we???) but
5539 -- we do at least check that both types are real, or both types are
5542 elsif Is_Real_Type (T1) /= Is_Real_Type (T2) then
5545 -- Here we check the bounds
5549 LB1 : constant Node_Id := Type_Low_Bound (T1);
5550 HB1 : constant Node_Id := Type_High_Bound (T1);
5551 LB2 : constant Node_Id := Type_Low_Bound (T2);
5552 HB2 : constant Node_Id := Type_High_Bound (T2);
5555 if Is_Real_Type (T1) then
5557 (Expr_Value_R (LB1) > Expr_Value_R (HB1))
5559 (Expr_Value_R (LB2) <= Expr_Value_R (LB1)
5561 Expr_Value_R (HB1) <= Expr_Value_R (HB2));
5565 (Expr_Value (LB1) > Expr_Value (HB1))
5567 (Expr_Value (LB2) <= Expr_Value (LB1)
5569 Expr_Value (HB1) <= Expr_Value (HB2));
5576 elsif Is_Access_Type (T1) then
5577 return (not Is_Constrained (T2)
5578 or else (Subtypes_Statically_Match
5579 (Designated_Type (T1), Designated_Type (T2))))
5580 and then not (Can_Never_Be_Null (T2)
5581 and then not Can_Never_Be_Null (T1));
5586 return (Is_Composite_Type (T1) and then not Is_Constrained (T2))
5587 or else Subtypes_Statically_Match (T1, T2, Formal_Derived_Matching);
5589 end Subtypes_Statically_Compatible;
5591 -------------------------------
5592 -- Subtypes_Statically_Match --
5593 -------------------------------
5595 -- Subtypes statically match if they have statically matching constraints
5596 -- (RM 4.9.1(2)). Constraints statically match if there are none, or if
5597 -- they are the same identical constraint, or if they are static and the
5598 -- values match (RM 4.9.1(1)).
5600 -- In addition, in GNAT, the object size (Esize) values of the types must
5601 -- match if they are set (unless checking an actual for a formal derived
5602 -- type). The use of 'Object_Size can cause this to be false even if the
5603 -- types would otherwise match in the RM sense.
5605 function Subtypes_Statically_Match
5608 Formal_Derived_Matching : Boolean := False) return Boolean
5611 -- A type always statically matches itself
5616 -- No match if sizes different (from use of 'Object_Size). This test
5617 -- is excluded if Formal_Derived_Matching is True, as the base types
5618 -- can be different in that case and typically have different sizes
5619 -- (and Esizes can be set when Frontend_Layout_On_Target is True).
5621 elsif not Formal_Derived_Matching
5622 and then Known_Static_Esize (T1)
5623 and then Known_Static_Esize (T2)
5624 and then Esize (T1) /= Esize (T2)
5628 -- No match if predicates do not match
5630 elsif not Predicates_Match (T1, T2) then
5635 elsif Is_Scalar_Type (T1) then
5637 -- Base types must be the same
5639 if Base_Type (T1) /= Base_Type (T2) then
5643 -- A constrained numeric subtype never matches an unconstrained
5644 -- subtype, i.e. both types must be constrained or unconstrained.
5646 -- To understand the requirement for this test, see RM 4.9.1(1).
5647 -- As is made clear in RM 3.5.4(11), type Integer, for example is
5648 -- a constrained subtype with constraint bounds matching the bounds
5649 -- of its corresponding unconstrained base type. In this situation,
5650 -- Integer and Integer'Base do not statically match, even though
5651 -- they have the same bounds.
5653 -- We only apply this test to types in Standard and types that appear
5654 -- in user programs. That way, we do not have to be too careful about
5655 -- setting Is_Constrained right for Itypes.
5657 if Is_Numeric_Type (T1)
5658 and then (Is_Constrained (T1) /= Is_Constrained (T2))
5659 and then (Scope (T1) = Standard_Standard
5660 or else Comes_From_Source (T1))
5661 and then (Scope (T2) = Standard_Standard
5662 or else Comes_From_Source (T2))
5666 -- A generic scalar type does not statically match its base type
5667 -- (AI-311). In this case we make sure that the formals, which are
5668 -- first subtypes of their bases, are constrained.
5670 elsif Is_Generic_Type (T1)
5671 and then Is_Generic_Type (T2)
5672 and then (Is_Constrained (T1) /= Is_Constrained (T2))
5677 -- If there was an error in either range, then just assume the types
5678 -- statically match to avoid further junk errors.
5680 if No (Scalar_Range (T1)) or else No (Scalar_Range (T2))
5681 or else Error_Posted (Scalar_Range (T1))
5682 or else Error_Posted (Scalar_Range (T2))
5687 -- Otherwise both types have bounds that can be compared
5690 LB1 : constant Node_Id := Type_Low_Bound (T1);
5691 HB1 : constant Node_Id := Type_High_Bound (T1);
5692 LB2 : constant Node_Id := Type_Low_Bound (T2);
5693 HB2 : constant Node_Id := Type_High_Bound (T2);
5696 -- If the bounds are the same tree node, then match (common case)
5698 if LB1 = LB2 and then HB1 = HB2 then
5701 -- Otherwise bounds must be static and identical value
5704 if not Is_OK_Static_Subtype (T1)
5705 or else not Is_OK_Static_Subtype (T2)
5709 -- If either type has constraint error bounds, then say that
5710 -- they match to avoid junk cascaded errors here.
5712 elsif not Is_OK_Static_Subtype (T1)
5713 or else not Is_OK_Static_Subtype (T2)
5717 elsif Is_Real_Type (T1) then
5719 (Expr_Value_R (LB1) = Expr_Value_R (LB2))
5721 (Expr_Value_R (HB1) = Expr_Value_R (HB2));
5725 Expr_Value (LB1) = Expr_Value (LB2)
5727 Expr_Value (HB1) = Expr_Value (HB2);
5732 -- Type with discriminants
5734 elsif Has_Discriminants (T1) or else Has_Discriminants (T2) then
5736 -- Because of view exchanges in multiple instantiations, conformance
5737 -- checking might try to match a partial view of a type with no
5738 -- discriminants with a full view that has defaulted discriminants.
5739 -- In such a case, use the discriminant constraint of the full view,
5740 -- which must exist because we know that the two subtypes have the
5743 if Has_Discriminants (T1) /= Has_Discriminants (T2) then
5745 if Is_Private_Type (T2)
5746 and then Present (Full_View (T2))
5747 and then Has_Discriminants (Full_View (T2))
5749 return Subtypes_Statically_Match (T1, Full_View (T2));
5751 elsif Is_Private_Type (T1)
5752 and then Present (Full_View (T1))
5753 and then Has_Discriminants (Full_View (T1))
5755 return Subtypes_Statically_Match (Full_View (T1), T2);
5766 DL1 : constant Elist_Id := Discriminant_Constraint (T1);
5767 DL2 : constant Elist_Id := Discriminant_Constraint (T2);
5775 elsif Is_Constrained (T1) /= Is_Constrained (T2) then
5779 -- Now loop through the discriminant constraints
5781 -- Note: the guard here seems necessary, since it is possible at
5782 -- least for DL1 to be No_Elist. Not clear this is reasonable ???
5784 if Present (DL1) and then Present (DL2) then
5785 DA1 := First_Elmt (DL1);
5786 DA2 := First_Elmt (DL2);
5787 while Present (DA1) loop
5789 Expr1 : constant Node_Id := Node (DA1);
5790 Expr2 : constant Node_Id := Node (DA2);
5793 if not Is_OK_Static_Expression (Expr1)
5794 or else not Is_OK_Static_Expression (Expr2)
5798 -- If either expression raised a constraint error,
5799 -- consider the expressions as matching, since this
5800 -- helps to prevent cascading errors.
5802 elsif Raises_Constraint_Error (Expr1)
5803 or else Raises_Constraint_Error (Expr2)
5807 elsif Expr_Value (Expr1) /= Expr_Value (Expr2) then
5820 -- A definite type does not match an indefinite or classwide type.
5821 -- However, a generic type with unknown discriminants may be
5822 -- instantiated with a type with no discriminants, and conformance
5823 -- checking on an inherited operation may compare the actual with the
5824 -- subtype that renames it in the instance.
5826 elsif Has_Unknown_Discriminants (T1) /= Has_Unknown_Discriminants (T2)
5829 Is_Generic_Actual_Type (T1) or else Is_Generic_Actual_Type (T2);
5833 elsif Is_Array_Type (T1) then
5835 -- If either subtype is unconstrained then both must be, and if both
5836 -- are unconstrained then no further checking is needed.
5838 if not Is_Constrained (T1) or else not Is_Constrained (T2) then
5839 return not (Is_Constrained (T1) or else Is_Constrained (T2));
5842 -- Both subtypes are constrained, so check that the index subtypes
5843 -- statically match.
5846 Index1 : Node_Id := First_Index (T1);
5847 Index2 : Node_Id := First_Index (T2);
5850 while Present (Index1) loop
5852 Subtypes_Statically_Match (Etype (Index1), Etype (Index2))
5857 Next_Index (Index1);
5858 Next_Index (Index2);
5864 elsif Is_Access_Type (T1) then
5865 if Can_Never_Be_Null (T1) /= Can_Never_Be_Null (T2) then
5868 elsif Ekind_In (T1, E_Access_Subprogram_Type,
5869 E_Anonymous_Access_Subprogram_Type)
5873 (Designated_Type (T1),
5874 Designated_Type (T2));
5877 Subtypes_Statically_Match
5878 (Designated_Type (T1),
5879 Designated_Type (T2))
5880 and then Is_Access_Constant (T1) = Is_Access_Constant (T2);
5883 -- All other types definitely match
5888 end Subtypes_Statically_Match;
5894 function Test (Cond : Boolean) return Uint is
5903 ---------------------------------
5904 -- Test_Expression_Is_Foldable --
5905 ---------------------------------
5909 procedure Test_Expression_Is_Foldable
5919 if Debug_Flag_Dot_F and then In_Extended_Main_Source_Unit (N) then
5923 -- If operand is Any_Type, just propagate to result and do not
5924 -- try to fold, this prevents cascaded errors.
5926 if Etype (Op1) = Any_Type then
5927 Set_Etype (N, Any_Type);
5930 -- If operand raises constraint error, then replace node N with the
5931 -- raise constraint error node, and we are obviously not foldable.
5932 -- Note that this replacement inherits the Is_Static_Expression flag
5933 -- from the operand.
5935 elsif Raises_Constraint_Error (Op1) then
5936 Rewrite_In_Raise_CE (N, Op1);
5939 -- If the operand is not static, then the result is not static, and
5940 -- all we have to do is to check the operand since it is now known
5941 -- to appear in a non-static context.
5943 elsif not Is_Static_Expression (Op1) then
5944 Check_Non_Static_Context (Op1);
5945 Fold := Compile_Time_Known_Value (Op1);
5948 -- An expression of a formal modular type is not foldable because
5949 -- the modulus is unknown.
5951 elsif Is_Modular_Integer_Type (Etype (Op1))
5952 and then Is_Generic_Type (Etype (Op1))
5954 Check_Non_Static_Context (Op1);
5957 -- Here we have the case of an operand whose type is OK, which is
5958 -- static, and which does not raise constraint error, we can fold.
5961 Set_Is_Static_Expression (N);
5965 end Test_Expression_Is_Foldable;
5969 procedure Test_Expression_Is_Foldable
5975 CRT_Safe : Boolean := False)
5977 Rstat : constant Boolean := Is_Static_Expression (Op1)
5979 Is_Static_Expression (Op2);
5985 -- Inhibit folding if -gnatd.f flag set
5987 if Debug_Flag_Dot_F and then In_Extended_Main_Source_Unit (N) then
5991 -- If either operand is Any_Type, just propagate to result and
5992 -- do not try to fold, this prevents cascaded errors.
5994 if Etype (Op1) = Any_Type or else Etype (Op2) = Any_Type then
5995 Set_Etype (N, Any_Type);
5998 -- If left operand raises constraint error, then replace node N with the
5999 -- Raise_Constraint_Error node, and we are obviously not foldable.
6000 -- Is_Static_Expression is set from the two operands in the normal way,
6001 -- and we check the right operand if it is in a non-static context.
6003 elsif Raises_Constraint_Error (Op1) then
6005 Check_Non_Static_Context (Op2);
6008 Rewrite_In_Raise_CE (N, Op1);
6009 Set_Is_Static_Expression (N, Rstat);
6012 -- Similar processing for the case of the right operand. Note that we
6013 -- don't use this routine for the short-circuit case, so we do not have
6014 -- to worry about that special case here.
6016 elsif Raises_Constraint_Error (Op2) then
6018 Check_Non_Static_Context (Op1);
6021 Rewrite_In_Raise_CE (N, Op2);
6022 Set_Is_Static_Expression (N, Rstat);
6025 -- Exclude expressions of a generic modular type, as above
6027 elsif Is_Modular_Integer_Type (Etype (Op1))
6028 and then Is_Generic_Type (Etype (Op1))
6030 Check_Non_Static_Context (Op1);
6033 -- If result is not static, then check non-static contexts on operands
6034 -- since one of them may be static and the other one may not be static.
6036 elsif not Rstat then
6037 Check_Non_Static_Context (Op1);
6038 Check_Non_Static_Context (Op2);
6041 Fold := CRT_Safe_Compile_Time_Known_Value (Op1)
6042 and then CRT_Safe_Compile_Time_Known_Value (Op2);
6044 Fold := Compile_Time_Known_Value (Op1)
6045 and then Compile_Time_Known_Value (Op2);
6050 -- Else result is static and foldable. Both operands are static, and
6051 -- neither raises constraint error, so we can definitely fold.
6054 Set_Is_Static_Expression (N);
6059 end Test_Expression_Is_Foldable;
6065 function Test_In_Range
6068 Assume_Valid : Boolean;
6069 Fixed_Int : Boolean;
6070 Int_Real : Boolean) return Range_Membership
6075 pragma Warnings (Off, Assume_Valid);
6076 -- For now Assume_Valid is unreferenced since the current implementation
6077 -- always returns Unknown if N is not a compile time known value, but we
6078 -- keep the parameter to allow for future enhancements in which we try
6079 -- to get the information in the variable case as well.
6082 -- Expression that raises constraint error is an odd case. We certainly
6083 -- do not want to consider it to be in range. It might make sense to
6084 -- consider it always out of range, but this causes incorrect error
6085 -- messages about static expressions out of range. So we just return
6086 -- Unknown, which is always safe.
6088 if Raises_Constraint_Error (N) then
6091 -- Universal types have no range limits, so always in range
6093 elsif Typ = Universal_Integer or else Typ = Universal_Real then
6096 -- Never known if not scalar type. Don't know if this can actually
6097 -- happen, but our spec allows it, so we must check.
6099 elsif not Is_Scalar_Type (Typ) then
6102 -- Never known if this is a generic type, since the bounds of generic
6103 -- types are junk. Note that if we only checked for static expressions
6104 -- (instead of compile time known values) below, we would not need this
6105 -- check, because values of a generic type can never be static, but they
6106 -- can be known at compile time.
6108 elsif Is_Generic_Type (Typ) then
6111 -- Case of a known compile time value, where we can check if it is in
6112 -- the bounds of the given type.
6114 elsif Compile_Time_Known_Value (N) then
6123 Lo := Type_Low_Bound (Typ);
6124 Hi := Type_High_Bound (Typ);
6126 LB_Known := Compile_Time_Known_Value (Lo);
6127 HB_Known := Compile_Time_Known_Value (Hi);
6129 -- Fixed point types should be considered as such only if flag
6130 -- Fixed_Int is set to False.
6132 if Is_Floating_Point_Type (Typ)
6133 or else (Is_Fixed_Point_Type (Typ) and then not Fixed_Int)
6136 Valr := Expr_Value_R (N);
6138 if LB_Known and HB_Known then
6139 if Valr >= Expr_Value_R (Lo)
6141 Valr <= Expr_Value_R (Hi)
6145 return Out_Of_Range;
6148 elsif (LB_Known and then Valr < Expr_Value_R (Lo))
6150 (HB_Known and then Valr > Expr_Value_R (Hi))
6152 return Out_Of_Range;
6159 Val := Expr_Value (N);
6161 if LB_Known and HB_Known then
6162 if Val >= Expr_Value (Lo) and then Val <= Expr_Value (Hi)
6166 return Out_Of_Range;
6169 elsif (LB_Known and then Val < Expr_Value (Lo))
6171 (HB_Known and then Val > Expr_Value (Hi))
6173 return Out_Of_Range;
6181 -- Here for value not known at compile time. Case of expression subtype
6182 -- is Typ or is a subtype of Typ, and we can assume expression is valid.
6183 -- In this case we know it is in range without knowing its value.
6186 and then (Etype (N) = Typ or else Is_Subtype_Of (Etype (N), Typ))
6190 -- For all other cases, result is unknown
6201 procedure To_Bits (U : Uint; B : out Bits) is
6203 for J in 0 .. B'Last loop
6204 B (J) := (U / (2 ** J)) mod 2 /= 0;
6208 --------------------
6209 -- Why_Not_Static --
6210 --------------------
6212 procedure Why_Not_Static (Expr : Node_Id) is
6213 N : constant Node_Id := Original_Node (Expr);
6219 procedure Why_Not_Static_List (L : List_Id);
6220 -- A version that can be called on a list of expressions. Finds all
6221 -- non-static violations in any element of the list.
6223 -------------------------
6224 -- Why_Not_Static_List --
6225 -------------------------
6227 procedure Why_Not_Static_List (L : List_Id) is
6230 if Is_Non_Empty_List (L) then
6232 while Present (N) loop
6237 end Why_Not_Static_List;
6239 -- Start of processing for Why_Not_Static
6242 -- Ignore call on error or empty node
6244 if No (Expr) or else Nkind (Expr) = N_Error then
6248 -- Preprocessing for sub expressions
6250 if Nkind (Expr) in N_Subexpr then
6252 -- Nothing to do if expression is static
6254 if Is_OK_Static_Expression (Expr) then
6258 -- Test for constraint error raised
6260 if Raises_Constraint_Error (Expr) then
6262 -- Special case membership to find out which piece to flag
6264 if Nkind (N) in N_Membership_Test then
6265 if Raises_Constraint_Error (Left_Opnd (N)) then
6266 Why_Not_Static (Left_Opnd (N));
6269 elsif Present (Right_Opnd (N))
6270 and then Raises_Constraint_Error (Right_Opnd (N))
6272 Why_Not_Static (Right_Opnd (N));
6276 pragma Assert (Present (Alternatives (N)));
6278 Alt := First (Alternatives (N));
6279 while Present (Alt) loop
6280 if Raises_Constraint_Error (Alt) then
6281 Why_Not_Static (Alt);
6289 -- Special case a range to find out which bound to flag
6291 elsif Nkind (N) = N_Range then
6292 if Raises_Constraint_Error (Low_Bound (N)) then
6293 Why_Not_Static (Low_Bound (N));
6296 elsif Raises_Constraint_Error (High_Bound (N)) then
6297 Why_Not_Static (High_Bound (N));
6301 -- Special case attribute to see which part to flag
6303 elsif Nkind (N) = N_Attribute_Reference then
6304 if Raises_Constraint_Error (Prefix (N)) then
6305 Why_Not_Static (Prefix (N));
6309 if Present (Expressions (N)) then
6310 Exp := First (Expressions (N));
6311 while Present (Exp) loop
6312 if Raises_Constraint_Error (Exp) then
6313 Why_Not_Static (Exp);
6321 -- Special case a subtype name
6323 elsif Is_Entity_Name (Expr) and then Is_Type (Entity (Expr)) then
6325 ("!& is not a static subtype (RM 4.9(26))", N, Entity (Expr));
6329 -- End of special cases
6332 ("!expression raises exception, cannot be static (RM 4.9(34))",
6337 -- If no type, then something is pretty wrong, so ignore
6339 Typ := Etype (Expr);
6345 -- Type must be scalar or string type (but allow Bignum, since this
6346 -- is really a scalar type from our point of view in this diagnosis).
6348 if not Is_Scalar_Type (Typ)
6349 and then not Is_String_Type (Typ)
6350 and then not Is_RTE (Typ, RE_Bignum)
6353 ("!static expression must have scalar or string type " &
6359 -- If we got through those checks, test particular node kind
6365 when N_Expanded_Name | N_Identifier | N_Operator_Symbol =>
6368 if Is_Named_Number (E) then
6371 elsif Ekind (E) = E_Constant then
6373 -- One case we can give a metter message is when we have a
6374 -- string literal created by concatenating an aggregate with
6375 -- an others expression.
6377 Entity_Case : declare
6378 CV : constant Node_Id := Constant_Value (E);
6379 CO : constant Node_Id := Original_Node (CV);
6381 function Is_Aggregate (N : Node_Id) return Boolean;
6382 -- See if node N came from an others aggregate, if so
6383 -- return True and set Error_Msg_Sloc to aggregate.
6389 function Is_Aggregate (N : Node_Id) return Boolean is
6391 if Nkind (Original_Node (N)) = N_Aggregate then
6392 Error_Msg_Sloc := Sloc (Original_Node (N));
6395 elsif Is_Entity_Name (N)
6396 and then Ekind (Entity (N)) = E_Constant
6398 Nkind (Original_Node (Constant_Value (Entity (N)))) =
6402 Sloc (Original_Node (Constant_Value (Entity (N))));
6410 -- Start of processing for Entity_Case
6413 if Is_Aggregate (CV)
6414 or else (Nkind (CO) = N_Op_Concat
6415 and then (Is_Aggregate (Left_Opnd (CO))
6417 Is_Aggregate (Right_Opnd (CO))))
6419 Error_Msg_N ("!aggregate (#) is never static", N);
6421 elsif No (CV) or else not Is_Static_Expression (CV) then
6423 ("!& is not a static constant (RM 4.9(5))", N, E);
6427 elsif Is_Type (E) then
6429 ("!& is not a static subtype (RM 4.9(26))", N, E);
6433 ("!& is not static constant or named number "
6434 & "(RM 4.9(5))", N, E);
6439 when N_Binary_Op | N_Short_Circuit | N_Membership_Test =>
6440 if Nkind (N) in N_Op_Shift then
6442 ("!shift functions are never static (RM 4.9(6,18))", N);
6444 Why_Not_Static (Left_Opnd (N));
6445 Why_Not_Static (Right_Opnd (N));
6451 Why_Not_Static (Right_Opnd (N));
6453 -- Attribute reference
6455 when N_Attribute_Reference =>
6456 Why_Not_Static_List (Expressions (N));
6458 E := Etype (Prefix (N));
6460 if E = Standard_Void_Type then
6464 -- Special case non-scalar'Size since this is a common error
6466 if Attribute_Name (N) = Name_Size then
6468 ("!size attribute is only static for static scalar type "
6469 & "(RM 4.9(7,8))", N);
6473 elsif Is_Array_Type (E) then
6474 if not Nam_In (Attribute_Name (N), Name_First,
6479 ("!static array attribute must be Length, First, or Last "
6480 & "(RM 4.9(8))", N);
6482 -- Since we know the expression is not-static (we already
6483 -- tested for this, must mean array is not static).
6487 ("!prefix is non-static array (RM 4.9(8))", Prefix (N));
6492 -- Special case generic types, since again this is a common source
6495 elsif Is_Generic_Actual_Type (E) or else Is_Generic_Type (E) then
6497 ("!attribute of generic type is never static "
6498 & "(RM 4.9(7,8))", N);
6500 elsif Is_OK_Static_Subtype (E) then
6503 elsif Is_Scalar_Type (E) then
6505 ("!prefix type for attribute is not static scalar subtype "
6506 & "(RM 4.9(7))", N);
6510 ("!static attribute must apply to array/scalar type "
6511 & "(RM 4.9(7,8))", N);
6516 when N_String_Literal =>
6518 ("!subtype of string literal is non-static (RM 4.9(4))", N);
6520 -- Explicit dereference
6522 when N_Explicit_Dereference =>
6524 ("!explicit dereference is never static (RM 4.9)", N);
6528 when N_Function_Call =>
6529 Why_Not_Static_List (Parameter_Associations (N));
6531 -- Complain about non-static function call unless we have Bignum
6532 -- which means that the underlying expression is really some
6533 -- scalar arithmetic operation.
6535 if not Is_RTE (Typ, RE_Bignum) then
6536 Error_Msg_N ("!non-static function call (RM 4.9(6,18))", N);
6539 -- Parameter assocation (test actual parameter)
6541 when N_Parameter_Association =>
6542 Why_Not_Static (Explicit_Actual_Parameter (N));
6544 -- Indexed component
6546 when N_Indexed_Component =>
6547 Error_Msg_N ("!indexed component is never static (RM 4.9)", N);
6551 when N_Procedure_Call_Statement =>
6552 Error_Msg_N ("!procedure call is never static (RM 4.9)", N);
6554 -- Qualified expression (test expression)
6556 when N_Qualified_Expression =>
6557 Why_Not_Static (Expression (N));
6561 when N_Aggregate | N_Extension_Aggregate =>
6562 Error_Msg_N ("!an aggregate is never static (RM 4.9)", N);
6567 Why_Not_Static (Low_Bound (N));
6568 Why_Not_Static (High_Bound (N));
6570 -- Range constraint, test range expression
6572 when N_Range_Constraint =>
6573 Why_Not_Static (Range_Expression (N));
6575 -- Subtype indication, test constraint
6577 when N_Subtype_Indication =>
6578 Why_Not_Static (Constraint (N));
6580 -- Selected component
6582 when N_Selected_Component =>
6583 Error_Msg_N ("!selected component is never static (RM 4.9)", N);
6588 Error_Msg_N ("!slice is never static (RM 4.9)", N);
6590 when N_Type_Conversion =>
6591 Why_Not_Static (Expression (N));
6593 if not Is_Scalar_Type (Entity (Subtype_Mark (N)))
6594 or else not Is_OK_Static_Subtype (Entity (Subtype_Mark (N)))
6597 ("!static conversion requires static scalar subtype result "
6598 & "(RM 4.9(9))", N);
6601 -- Unchecked type conversion
6603 when N_Unchecked_Type_Conversion =>
6605 ("!unchecked type conversion is never static (RM 4.9)", N);
6607 -- All other cases, no reason to give