1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2005, 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 2, 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 COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 with Atree
; use Atree
;
28 with Checks
; use Checks
;
29 with Debug
; use Debug
;
30 with Einfo
; use Einfo
;
31 with Elists
; use Elists
;
32 with Errout
; use Errout
;
33 with Eval_Fat
; use Eval_Fat
;
34 with Exp_Util
; use Exp_Util
;
36 with Nmake
; use Nmake
;
37 with Nlists
; use Nlists
;
40 with Sem_Cat
; use Sem_Cat
;
41 with Sem_Ch6
; use Sem_Ch6
;
42 with Sem_Ch8
; use Sem_Ch8
;
43 with Sem_Res
; use Sem_Res
;
44 with Sem_Util
; use Sem_Util
;
45 with Sem_Type
; use Sem_Type
;
46 with Sem_Warn
; use Sem_Warn
;
47 with Sinfo
; use Sinfo
;
48 with Snames
; use Snames
;
49 with Stand
; use Stand
;
50 with Stringt
; use Stringt
;
51 with Tbuild
; use Tbuild
;
53 package body Sem_Eval
is
55 -----------------------------------------
56 -- Handling of Compile Time Evaluation --
57 -----------------------------------------
59 -- The compile time evaluation of expressions is distributed over several
60 -- Eval_xxx procedures. These procedures are called immediatedly after
61 -- a subexpression is resolved and is therefore accomplished in a bottom
62 -- up fashion. The flags are synthesized using the following approach.
64 -- Is_Static_Expression is determined by following the detailed rules
65 -- in RM 4.9(4-14). This involves testing the Is_Static_Expression
66 -- flag of the operands in many cases.
68 -- Raises_Constraint_Error is set if any of the operands have the flag
69 -- set or if an attempt to compute the value of the current expression
70 -- results in detection of a runtime constraint error.
72 -- As described in the spec, the requirement is that Is_Static_Expression
73 -- be accurately set, and in addition for nodes for which this flag is set,
74 -- Raises_Constraint_Error must also be set. Furthermore a node which has
75 -- Is_Static_Expression set, and Raises_Constraint_Error clear, then the
76 -- requirement is that the expression value must be precomputed, and the
77 -- node is either a literal, or the name of a constant entity whose value
78 -- is a static expression.
80 -- The general approach is as follows. First compute Is_Static_Expression.
81 -- If the node is not static, then the flag is left off in the node and
82 -- we are all done. Otherwise for a static node, we test if any of the
83 -- operands will raise constraint error, and if so, propagate the flag
84 -- Raises_Constraint_Error to the result node and we are done (since the
85 -- error was already posted at a lower level).
87 -- For the case of a static node whose operands do not raise constraint
88 -- error, we attempt to evaluate the node. If this evaluation succeeds,
89 -- then the node is replaced by the result of this computation. If the
90 -- evaluation raises constraint error, then we rewrite the node with
91 -- Apply_Compile_Time_Constraint_Error to raise the exception and also
92 -- to post appropriate error messages.
98 type Bits
is array (Nat
range <>) of Boolean;
99 -- Used to convert unsigned (modular) values for folding logical ops
101 -- The following definitions are used to maintain a cache of nodes that
102 -- have compile time known values. The cache is maintained only for
103 -- discrete types (the most common case), and is populated by calls to
104 -- Compile_Time_Known_Value and Expr_Value, but only used by Expr_Value
105 -- since it is possible for the status to change (in particular it is
106 -- possible for a node to get replaced by a constraint error node).
108 CV_Bits
: constant := 5;
109 -- Number of low order bits of Node_Id value used to reference entries
110 -- in the cache table.
112 CV_Cache_Size
: constant Nat
:= 2 ** CV_Bits
;
113 -- Size of cache for compile time values
115 subtype CV_Range
is Nat
range 0 .. CV_Cache_Size
;
117 type CV_Entry
is record
122 type CV_Cache_Array
is array (CV_Range
) of CV_Entry
;
124 CV_Cache
: CV_Cache_Array
:= (others => (Node_High_Bound
, Uint_0
));
125 -- This is the actual cache, with entries consisting of node/value pairs,
126 -- and the impossible value Node_High_Bound used for unset entries.
128 -----------------------
129 -- Local Subprograms --
130 -----------------------
132 function From_Bits
(B
: Bits
; T
: Entity_Id
) return Uint
;
133 -- Converts a bit string of length B'Length to a Uint value to be used
134 -- for a target of type T, which is a modular type. This procedure
135 -- includes the necessary reduction by the modulus in the case of a
136 -- non-binary modulus (for a binary modulus, the bit string is the
137 -- right length any way so all is well).
139 function Get_String_Val
(N
: Node_Id
) return Node_Id
;
140 -- Given a tree node for a folded string or character value, returns
141 -- the corresponding string literal or character literal (one of the
142 -- two must be available, or the operand would not have been marked
143 -- as foldable in the earlier analysis of the operation).
145 function OK_Bits
(N
: Node_Id
; Bits
: Uint
) return Boolean;
146 -- Bits represents the number of bits in an integer value to be computed
147 -- (but the value has not been computed yet). If this value in Bits is
148 -- reasonable, a result of True is returned, with the implication that
149 -- the caller should go ahead and complete the calculation. If the value
150 -- in Bits is unreasonably large, then an error is posted on node N, and
151 -- False is returned (and the caller skips the proposed calculation).
153 procedure Out_Of_Range
(N
: Node_Id
);
154 -- This procedure is called if it is determined that node N, which
155 -- appears in a non-static context, is a compile time known value
156 -- which is outside its range, i.e. the range of Etype. This is used
157 -- in contexts where this is an illegality if N is static, and should
158 -- generate a warning otherwise.
160 procedure Rewrite_In_Raise_CE
(N
: Node_Id
; Exp
: Node_Id
);
161 -- N and Exp are nodes representing an expression, Exp is known
162 -- to raise CE. N is rewritten in term of Exp in the optimal way.
164 function String_Type_Len
(Stype
: Entity_Id
) return Uint
;
165 -- Given a string type, determines the length of the index type, or,
166 -- if this index type is non-static, the length of the base type of
167 -- this index type. Note that if the string type is itself static,
168 -- then the index type is static, so the second case applies only
169 -- if the string type passed is non-static.
171 function Test
(Cond
: Boolean) return Uint
;
172 pragma Inline
(Test
);
173 -- This function simply returns the appropriate Boolean'Pos value
174 -- corresponding to the value of Cond as a universal integer. It is
175 -- used for producing the result of the static evaluation of the
178 procedure Test_Expression_Is_Foldable
183 -- Tests to see if expression N whose single operand is Op1 is foldable,
184 -- i.e. the operand value is known at compile time. If the operation is
185 -- foldable, then Fold is True on return, and Stat indicates whether
186 -- the result is static (i.e. both operands were static). Note that it
187 -- is quite possible for Fold to be True, and Stat to be False, since
188 -- there are cases in which we know the value of an operand even though
189 -- it is not technically static (e.g. the static lower bound of a range
190 -- whose upper bound is non-static).
192 -- If Stat is set False on return, then Expression_Is_Foldable makes a
193 -- call to Check_Non_Static_Context on the operand. If Fold is False on
194 -- return, then all processing is complete, and the caller should
195 -- return, since there is nothing else to do.
197 procedure Test_Expression_Is_Foldable
203 -- Same processing, except applies to an expression N with two operands
206 procedure To_Bits
(U
: Uint
; B
: out Bits
);
207 -- Converts a Uint value to a bit string of length B'Length
209 ------------------------------
210 -- Check_Non_Static_Context --
211 ------------------------------
213 procedure Check_Non_Static_Context
(N
: Node_Id
) is
214 T
: constant Entity_Id
:= Etype
(N
);
215 Checks_On
: constant Boolean :=
216 not Index_Checks_Suppressed
(T
)
217 and not Range_Checks_Suppressed
(T
);
220 -- Ignore cases of non-scalar types or error types
222 if T
= Any_Type
or else not Is_Scalar_Type
(T
) then
226 -- At this stage we have a scalar type. If we have an expression
227 -- that raises CE, then we already issued a warning or error msg
228 -- so there is nothing more to be done in this routine.
230 if Raises_Constraint_Error
(N
) then
234 -- Now we have a scalar type which is not marked as raising a
235 -- constraint error exception. The main purpose of this routine
236 -- is to deal with static expressions appearing in a non-static
237 -- context. That means that if we do not have a static expression
238 -- then there is not much to do. The one case that we deal with
239 -- here is that if we have a floating-point value that is out of
240 -- range, then we post a warning that an infinity will result.
242 if not Is_Static_Expression
(N
) then
243 if Is_Floating_Point_Type
(T
)
244 and then Is_Out_Of_Range
(N
, Base_Type
(T
))
247 ("?float value out of range, infinity will be generated", N
);
253 -- Here we have the case of outer level static expression of
254 -- scalar type, where the processing of this procedure is needed.
256 -- For real types, this is where we convert the value to a machine
257 -- number (see RM 4.9(38)). Also see ACVC test C490001. We should
258 -- only need to do this if the parent is a constant declaration,
259 -- since in other cases, gigi should do the necessary conversion
260 -- correctly, but experimentation shows that this is not the case
261 -- on all machines, in particular if we do not convert all literals
262 -- to machine values in non-static contexts, then ACVC test C490001
263 -- fails on Sparc/Solaris and SGI/Irix.
265 if Nkind
(N
) = N_Real_Literal
266 and then not Is_Machine_Number
(N
)
267 and then not Is_Generic_Type
(Etype
(N
))
268 and then Etype
(N
) /= Universal_Real
270 -- Check that value is in bounds before converting to machine
271 -- number, so as not to lose case where value overflows in the
272 -- least significant bit or less. See B490001.
274 if Is_Out_Of_Range
(N
, Base_Type
(T
)) then
279 -- Note: we have to copy the node, to avoid problems with conformance
280 -- of very similar numbers (see ACVC tests B4A010C and B63103A).
282 Rewrite
(N
, New_Copy
(N
));
284 if not Is_Floating_Point_Type
(T
) then
286 (N
, Corresponding_Integer_Value
(N
) * Small_Value
(T
));
288 elsif not UR_Is_Zero
(Realval
(N
)) then
290 -- Note: even though RM 4.9(38) specifies biased rounding,
291 -- this has been modified by AI-100 in order to prevent
292 -- confusing differences in rounding between static and
293 -- non-static expressions. AI-100 specifies that the effect
294 -- of such rounding is implementation dependent, and in GNAT
295 -- we round to nearest even to match the run-time behavior.
298 (N
, Machine
(Base_Type
(T
), Realval
(N
), Round_Even
, N
));
301 Set_Is_Machine_Number
(N
);
304 -- Check for out of range universal integer. This is a non-static
305 -- context, so the integer value must be in range of the runtime
306 -- representation of universal integers.
308 -- We do this only within an expression, because that is the only
309 -- case in which non-static universal integer values can occur, and
310 -- furthermore, Check_Non_Static_Context is currently (incorrectly???)
311 -- called in contexts like the expression of a number declaration where
312 -- we certainly want to allow out of range values.
314 if Etype
(N
) = Universal_Integer
315 and then Nkind
(N
) = N_Integer_Literal
316 and then Nkind
(Parent
(N
)) in N_Subexpr
318 (Intval
(N
) < Expr_Value
(Type_Low_Bound
(Universal_Integer
))
320 Intval
(N
) > Expr_Value
(Type_High_Bound
(Universal_Integer
)))
322 Apply_Compile_Time_Constraint_Error
323 (N
, "non-static universal integer value out of range?",
324 CE_Range_Check_Failed
);
326 -- Check out of range of base type
328 elsif Is_Out_Of_Range
(N
, Base_Type
(T
)) then
331 -- Give warning if outside subtype (where one or both of the
332 -- bounds of the subtype is static). This warning is omitted
333 -- if the expression appears in a range that could be null
334 -- (warnings are handled elsewhere for this case).
336 elsif T
/= Base_Type
(T
)
337 and then Nkind
(Parent
(N
)) /= N_Range
339 if Is_In_Range
(N
, T
) then
342 elsif Is_Out_Of_Range
(N
, T
) then
343 Apply_Compile_Time_Constraint_Error
344 (N
, "value not in range of}?", CE_Range_Check_Failed
);
347 Enable_Range_Check
(N
);
350 Set_Do_Range_Check
(N
, False);
353 end Check_Non_Static_Context
;
355 ---------------------------------
356 -- Check_String_Literal_Length --
357 ---------------------------------
359 procedure Check_String_Literal_Length
(N
: Node_Id
; Ttype
: Entity_Id
) is
361 if not Raises_Constraint_Error
(N
)
362 and then Is_Constrained
(Ttype
)
365 UI_From_Int
(String_Length
(Strval
(N
))) /= String_Type_Len
(Ttype
)
367 Apply_Compile_Time_Constraint_Error
368 (N
, "string length wrong for}?",
369 CE_Length_Check_Failed
,
374 end Check_String_Literal_Length
;
376 --------------------------
377 -- Compile_Time_Compare --
378 --------------------------
380 function Compile_Time_Compare
382 Rec
: Boolean := False) return Compare_Result
384 Ltyp
: constant Entity_Id
:= Etype
(L
);
385 Rtyp
: constant Entity_Id
:= Etype
(R
);
387 procedure Compare_Decompose
391 -- This procedure decomposes the node N into an expression node
392 -- and a signed offset, so that the value of N is equal to the
393 -- value of R plus the value V (which may be negative). If no
394 -- such decomposition is possible, then on return R is a copy
395 -- of N, and V is set to zero.
397 function Compare_Fixup
(N
: Node_Id
) return Node_Id
;
398 -- This function deals with replacing 'Last and 'First references
399 -- with their corresponding type bounds, which we then can compare.
400 -- The argument is the original node, the result is the identity,
401 -- unless we have a 'Last/'First reference in which case the value
402 -- returned is the appropriate type bound.
404 function Is_Same_Value
(L
, R
: Node_Id
) return Boolean;
405 -- Returns True iff L and R represent expressions that definitely
406 -- have identical (but not necessarily compile time known) values
407 -- Indeed the caller is expected to have already dealt with the
408 -- cases of compile time known values, so these are not tested here.
410 -----------------------
411 -- Compare_Decompose --
412 -----------------------
414 procedure Compare_Decompose
420 if Nkind
(N
) = N_Op_Add
421 and then Nkind
(Right_Opnd
(N
)) = N_Integer_Literal
424 V
:= Intval
(Right_Opnd
(N
));
427 elsif Nkind
(N
) = N_Op_Subtract
428 and then Nkind
(Right_Opnd
(N
)) = N_Integer_Literal
431 V
:= UI_Negate
(Intval
(Right_Opnd
(N
)));
434 elsif Nkind
(N
) = N_Attribute_Reference
then
436 if Attribute_Name
(N
) = Name_Succ
then
437 R
:= First
(Expressions
(N
));
441 elsif Attribute_Name
(N
) = Name_Pred
then
442 R
:= First
(Expressions
(N
));
450 end Compare_Decompose
;
456 function Compare_Fixup
(N
: Node_Id
) return Node_Id
is
462 if Nkind
(N
) = N_Attribute_Reference
463 and then (Attribute_Name
(N
) = Name_First
465 Attribute_Name
(N
) = Name_Last
)
467 Xtyp
:= Etype
(Prefix
(N
));
469 -- If we have no type, then just abandon the attempt to do
470 -- a fixup, this is probably the result of some other error.
476 -- Dereference an access type
478 if Is_Access_Type
(Xtyp
) then
479 Xtyp
:= Designated_Type
(Xtyp
);
482 -- If we don't have an array type at this stage, something
483 -- is peculiar, e.g. another error, and we abandon the attempt
486 if not Is_Array_Type
(Xtyp
) then
490 -- Ignore unconstrained array, since bounds are not meaningful
492 if not Is_Constrained
(Xtyp
) then
496 if Ekind
(Xtyp
) = E_String_Literal_Subtype
then
497 if Attribute_Name
(N
) = Name_First
then
498 return String_Literal_Low_Bound
(Xtyp
);
500 else -- Attribute_Name (N) = Name_Last
501 return Make_Integer_Literal
(Sloc
(N
),
502 Intval
=> Intval
(String_Literal_Low_Bound
(Xtyp
))
503 + String_Literal_Length
(Xtyp
));
507 -- Find correct index type
509 Indx
:= First_Index
(Xtyp
);
511 if Present
(Expressions
(N
)) then
512 Subs
:= UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
514 for J
in 2 .. Subs
loop
515 Indx
:= Next_Index
(Indx
);
519 Xtyp
:= Etype
(Indx
);
521 if Attribute_Name
(N
) = Name_First
then
522 return Type_Low_Bound
(Xtyp
);
524 else -- Attribute_Name (N) = Name_Last
525 return Type_High_Bound
(Xtyp
);
536 function Is_Same_Value
(L
, R
: Node_Id
) return Boolean is
537 Lf
: constant Node_Id
:= Compare_Fixup
(L
);
538 Rf
: constant Node_Id
:= Compare_Fixup
(R
);
540 function Is_Same_Subscript
(L
, R
: List_Id
) return Boolean;
541 -- L, R are the Expressions values from two attribute nodes
542 -- for First or Last attributes. Either may be set to No_List
543 -- if no expressions are present (indicating subscript 1).
544 -- The result is True if both expressions represent the same
545 -- subscript (note that one case is where one subscript is
546 -- missing and the other is explicitly set to 1).
548 -----------------------
549 -- Is_Same_Subscript --
550 -----------------------
552 function Is_Same_Subscript
(L
, R
: List_Id
) return Boolean is
558 return Expr_Value
(First
(R
)) = Uint_1
;
563 return Expr_Value
(First
(L
)) = Uint_1
;
565 return Expr_Value
(First
(L
)) = Expr_Value
(First
(R
));
568 end Is_Same_Subscript
;
570 -- Start of processing for Is_Same_Value
573 -- Values are the same if they are the same identifier and the
574 -- identifier refers to a constant object (E_Constant). This
575 -- does not however apply to Float types, since we may have two
576 -- NaN values and they should never compare equal.
578 if Nkind
(Lf
) = N_Identifier
and then Nkind
(Rf
) = N_Identifier
579 and then Entity
(Lf
) = Entity
(Rf
)
580 and then not Is_Floating_Point_Type
(Etype
(L
))
581 and then (Ekind
(Entity
(Lf
)) = E_Constant
or else
582 Ekind
(Entity
(Lf
)) = E_In_Parameter
or else
583 Ekind
(Entity
(Lf
)) = E_Loop_Parameter
)
587 -- Or if they are compile time known and identical
589 elsif Compile_Time_Known_Value
(Lf
)
591 Compile_Time_Known_Value
(Rf
)
592 and then Expr_Value
(Lf
) = Expr_Value
(Rf
)
596 -- Or if they are both 'First or 'Last values applying to the
597 -- same entity (first and last don't change even if value does)
599 elsif Nkind
(Lf
) = N_Attribute_Reference
601 Nkind
(Rf
) = N_Attribute_Reference
602 and then Attribute_Name
(Lf
) = Attribute_Name
(Rf
)
603 and then (Attribute_Name
(Lf
) = Name_First
605 Attribute_Name
(Lf
) = Name_Last
)
606 and then Is_Entity_Name
(Prefix
(Lf
))
607 and then Is_Entity_Name
(Prefix
(Rf
))
608 and then Entity
(Prefix
(Lf
)) = Entity
(Prefix
(Rf
))
609 and then Is_Same_Subscript
(Expressions
(Lf
), Expressions
(Rf
))
613 -- All other cases, we can't tell
620 -- Start of processing for Compile_Time_Compare
623 -- If either operand could raise constraint error, then we cannot
624 -- know the result at compile time (since CE may be raised!)
626 if not (Cannot_Raise_Constraint_Error
(L
)
628 Cannot_Raise_Constraint_Error
(R
))
633 -- Identical operands are most certainly equal
638 -- If expressions have no types, then do not attempt to determine
639 -- if they are the same, since something funny is going on. One
640 -- case in which this happens is during generic template analysis,
641 -- when bounds are not fully analyzed.
643 elsif No
(Ltyp
) or else No
(Rtyp
) then
646 -- We only attempt compile time analysis for scalar values, and
647 -- not for packed arrays represented as modular types, where the
648 -- semantics of comparison is quite different.
650 elsif not Is_Scalar_Type
(Ltyp
)
651 or else Is_Packed_Array_Type
(Ltyp
)
655 -- Case where comparison involves two compile time known values
657 elsif Compile_Time_Known_Value
(L
)
658 and then Compile_Time_Known_Value
(R
)
660 -- For the floating-point case, we have to be a little careful, since
661 -- at compile time we are dealing with universal exact values, but at
662 -- runtime, these will be in non-exact target form. That's why the
663 -- returned results are LE and GE below instead of LT and GT.
665 if Is_Floating_Point_Type
(Ltyp
)
667 Is_Floating_Point_Type
(Rtyp
)
670 Lo
: constant Ureal
:= Expr_Value_R
(L
);
671 Hi
: constant Ureal
:= Expr_Value_R
(R
);
683 -- For the integer case we know exactly (note that this includes the
684 -- fixed-point case, where we know the run time integer values now)
688 Lo
: constant Uint
:= Expr_Value
(L
);
689 Hi
: constant Uint
:= Expr_Value
(R
);
702 -- Cases where at least one operand is not known at compile time
705 -- Here is where we check for comparisons against maximum bounds of
706 -- types, where we know that no value can be outside the bounds of
707 -- the subtype. Note that this routine is allowed to assume that all
708 -- expressions are within their subtype bounds. Callers wishing to
709 -- deal with possibly invalid values must in any case take special
710 -- steps (e.g. conversions to larger types) to avoid this kind of
711 -- optimization, which is always considered to be valid. We do not
712 -- attempt this optimization with generic types, since the type
713 -- bounds may not be meaningful in this case.
715 -- We are in danger of an infinite recursion here. It does not seem
716 -- useful to go more than one level deep, so the parameter Rec is
717 -- used to protect ourselves against this infinite recursion.
720 and then Is_Discrete_Type
(Ltyp
)
721 and then Is_Discrete_Type
(Rtyp
)
722 and then not Is_Generic_Type
(Ltyp
)
723 and then not Is_Generic_Type
(Rtyp
)
725 -- See if we can get a decisive check against one operand and
726 -- a bound of the other operand (four possible tests here).
728 case Compile_Time_Compare
(L
, Type_Low_Bound
(Rtyp
), True) is
729 when LT
=> return LT
;
730 when LE
=> return LE
;
731 when EQ
=> return LE
;
735 case Compile_Time_Compare
(L
, Type_High_Bound
(Rtyp
), True) is
736 when GT
=> return GT
;
737 when GE
=> return GE
;
738 when EQ
=> return GE
;
742 case Compile_Time_Compare
(Type_Low_Bound
(Ltyp
), R
, True) is
743 when GT
=> return GT
;
744 when GE
=> return GE
;
745 when EQ
=> return GE
;
749 case Compile_Time_Compare
(Type_High_Bound
(Ltyp
), R
, True) is
750 when LT
=> return LT
;
751 when LE
=> return LE
;
752 when EQ
=> return LE
;
757 -- Next attempt is to decompose the expressions to extract
758 -- a constant offset resulting from the use of any of the forms:
765 -- Then we see if the two expressions are the same value, and if so
766 -- the result is obtained by comparing the offsets.
775 Compare_Decompose
(L
, Lnode
, Loffs
);
776 Compare_Decompose
(R
, Rnode
, Roffs
);
778 if Is_Same_Value
(Lnode
, Rnode
) then
779 if Loffs
= Roffs
then
782 elsif Loffs
< Roffs
then
789 -- If the expressions are different, we cannot say at compile
790 -- time how they compare, so we return the Unknown indication.
797 end Compile_Time_Compare
;
799 -------------------------------
800 -- Compile_Time_Known_Bounds --
801 -------------------------------
803 function Compile_Time_Known_Bounds
(T
: Entity_Id
) return Boolean is
808 if not Is_Array_Type
(T
) then
812 Indx
:= First_Index
(T
);
813 while Present
(Indx
) loop
814 Typ
:= Underlying_Type
(Etype
(Indx
));
815 if not Compile_Time_Known_Value
(Type_Low_Bound
(Typ
)) then
817 elsif not Compile_Time_Known_Value
(Type_High_Bound
(Typ
)) then
825 end Compile_Time_Known_Bounds
;
827 ------------------------------
828 -- Compile_Time_Known_Value --
829 ------------------------------
831 function Compile_Time_Known_Value
(Op
: Node_Id
) return Boolean is
832 K
: constant Node_Kind
:= Nkind
(Op
);
833 CV_Ent
: CV_Entry
renames CV_Cache
(Nat
(Op
) mod CV_Cache_Size
);
836 -- Never known at compile time if bad type or raises constraint error
837 -- or empty (latter case occurs only as a result of a previous error)
841 or else Etype
(Op
) = Any_Type
842 or else Raises_Constraint_Error
(Op
)
847 -- If this is not a static expression and we are in configurable run
848 -- time mode, then we consider it not known at compile time. This
849 -- avoids anomalies where whether something is permitted with a given
850 -- configurable run-time library depends on how good the compiler is
851 -- at optimizing and knowing that things are constant when they
854 if Configurable_Run_Time_Mode
and then not Is_Static_Expression
(Op
) then
858 -- If we have an entity name, then see if it is the name of a constant
859 -- and if so, test the corresponding constant value, or the name of
860 -- an enumeration literal, which is always a constant.
862 if Present
(Etype
(Op
)) and then Is_Entity_Name
(Op
) then
864 E
: constant Entity_Id
:= Entity
(Op
);
868 -- Never known at compile time if it is a packed array value.
869 -- We might want to try to evaluate these at compile time one
870 -- day, but we do not make that attempt now.
872 if Is_Packed_Array_Type
(Etype
(Op
)) then
876 if Ekind
(E
) = E_Enumeration_Literal
then
879 elsif Ekind
(E
) = E_Constant
then
880 V
:= Constant_Value
(E
);
881 return Present
(V
) and then Compile_Time_Known_Value
(V
);
885 -- We have a value, see if it is compile time known
888 -- Integer literals are worth storing in the cache
890 if K
= N_Integer_Literal
then
892 CV_Ent
.V
:= Intval
(Op
);
895 -- Other literals and NULL are known at compile time
898 K
= N_Character_Literal
908 -- Any reference to Null_Parameter is known at compile time. No
909 -- other attribute references (that have not already been folded)
910 -- are known at compile time.
912 elsif K
= N_Attribute_Reference
then
913 return Attribute_Name
(Op
) = Name_Null_Parameter
;
917 -- If we fall through, not known at compile time
921 -- If we get an exception while trying to do this test, then some error
922 -- has occurred, and we simply say that the value is not known after all
927 end Compile_Time_Known_Value
;
929 --------------------------------------
930 -- Compile_Time_Known_Value_Or_Aggr --
931 --------------------------------------
933 function Compile_Time_Known_Value_Or_Aggr
(Op
: Node_Id
) return Boolean is
935 -- If we have an entity name, then see if it is the name of a constant
936 -- and if so, test the corresponding constant value, or the name of
937 -- an enumeration literal, which is always a constant.
939 if Is_Entity_Name
(Op
) then
941 E
: constant Entity_Id
:= Entity
(Op
);
945 if Ekind
(E
) = E_Enumeration_Literal
then
948 elsif Ekind
(E
) /= E_Constant
then
952 V
:= Constant_Value
(E
);
954 and then Compile_Time_Known_Value_Or_Aggr
(V
);
958 -- We have a value, see if it is compile time known
961 if Compile_Time_Known_Value
(Op
) then
964 elsif Nkind
(Op
) = N_Aggregate
then
966 if Present
(Expressions
(Op
)) then
971 Expr
:= First
(Expressions
(Op
));
972 while Present
(Expr
) loop
973 if not Compile_Time_Known_Value_Or_Aggr
(Expr
) then
982 if Present
(Component_Associations
(Op
)) then
987 Cass
:= First
(Component_Associations
(Op
));
988 while Present
(Cass
) loop
990 Compile_Time_Known_Value_Or_Aggr
(Expression
(Cass
))
1002 -- All other types of values are not known at compile time
1009 end Compile_Time_Known_Value_Or_Aggr
;
1015 -- This is only called for actuals of functions that are not predefined
1016 -- operators (which have already been rewritten as operators at this
1017 -- stage), so the call can never be folded, and all that needs doing for
1018 -- the actual is to do the check for a non-static context.
1020 procedure Eval_Actual
(N
: Node_Id
) is
1022 Check_Non_Static_Context
(N
);
1025 --------------------
1026 -- Eval_Allocator --
1027 --------------------
1029 -- Allocators are never static, so all we have to do is to do the
1030 -- check for a non-static context if an expression is present.
1032 procedure Eval_Allocator
(N
: Node_Id
) is
1033 Expr
: constant Node_Id
:= Expression
(N
);
1036 if Nkind
(Expr
) = N_Qualified_Expression
then
1037 Check_Non_Static_Context
(Expression
(Expr
));
1041 ------------------------
1042 -- Eval_Arithmetic_Op --
1043 ------------------------
1045 -- Arithmetic operations are static functions, so the result is static
1046 -- if both operands are static (RM 4.9(7), 4.9(20)).
1048 procedure Eval_Arithmetic_Op
(N
: Node_Id
) is
1049 Left
: constant Node_Id
:= Left_Opnd
(N
);
1050 Right
: constant Node_Id
:= Right_Opnd
(N
);
1051 Ltype
: constant Entity_Id
:= Etype
(Left
);
1052 Rtype
: constant Entity_Id
:= Etype
(Right
);
1057 -- If not foldable we are done
1059 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
1065 -- Fold for cases where both operands are of integer type
1067 if Is_Integer_Type
(Ltype
) and then Is_Integer_Type
(Rtype
) then
1069 Left_Int
: constant Uint
:= Expr_Value
(Left
);
1070 Right_Int
: constant Uint
:= Expr_Value
(Right
);
1077 Result
:= Left_Int
+ Right_Int
;
1079 when N_Op_Subtract
=>
1080 Result
:= Left_Int
- Right_Int
;
1082 when N_Op_Multiply
=>
1085 (Num_Bits
(Left_Int
) + Num_Bits
(Right_Int
)))
1087 Result
:= Left_Int
* Right_Int
;
1094 -- The exception Constraint_Error is raised by integer
1095 -- division, rem and mod if the right operand is zero.
1097 if Right_Int
= 0 then
1098 Apply_Compile_Time_Constraint_Error
1099 (N
, "division by zero",
1105 Result
:= Left_Int
/ Right_Int
;
1110 -- The exception Constraint_Error is raised by integer
1111 -- division, rem and mod if the right operand is zero.
1113 if Right_Int
= 0 then
1114 Apply_Compile_Time_Constraint_Error
1115 (N
, "mod with zero divisor",
1120 Result
:= Left_Int
mod Right_Int
;
1125 -- The exception Constraint_Error is raised by integer
1126 -- division, rem and mod if the right operand is zero.
1128 if Right_Int
= 0 then
1129 Apply_Compile_Time_Constraint_Error
1130 (N
, "rem with zero divisor",
1136 Result
:= Left_Int
rem Right_Int
;
1140 raise Program_Error
;
1143 -- Adjust the result by the modulus if the type is a modular type
1145 if Is_Modular_Integer_Type
(Ltype
) then
1146 Result
:= Result
mod Modulus
(Ltype
);
1148 -- For a signed integer type, check non-static overflow
1150 elsif (not Stat
) and then Is_Signed_Integer_Type
(Ltype
) then
1152 BT
: constant Entity_Id
:= Base_Type
(Ltype
);
1153 Lo
: constant Uint
:= Expr_Value
(Type_Low_Bound
(BT
));
1154 Hi
: constant Uint
:= Expr_Value
(Type_High_Bound
(BT
));
1156 if Result
< Lo
or else Result
> Hi
then
1157 Apply_Compile_Time_Constraint_Error
1158 (N
, "value not in range of }?",
1159 CE_Overflow_Check_Failed
,
1166 -- If we get here we can fold the result
1168 Fold_Uint
(N
, Result
, Stat
);
1171 -- Cases where at least one operand is a real. We handle the cases
1172 -- of both reals, or mixed/real integer cases (the latter happen
1173 -- only for divide and multiply, and the result is always real).
1175 elsif Is_Real_Type
(Ltype
) or else Is_Real_Type
(Rtype
) then
1182 if Is_Real_Type
(Ltype
) then
1183 Left_Real
:= Expr_Value_R
(Left
);
1185 Left_Real
:= UR_From_Uint
(Expr_Value
(Left
));
1188 if Is_Real_Type
(Rtype
) then
1189 Right_Real
:= Expr_Value_R
(Right
);
1191 Right_Real
:= UR_From_Uint
(Expr_Value
(Right
));
1194 if Nkind
(N
) = N_Op_Add
then
1195 Result
:= Left_Real
+ Right_Real
;
1197 elsif Nkind
(N
) = N_Op_Subtract
then
1198 Result
:= Left_Real
- Right_Real
;
1200 elsif Nkind
(N
) = N_Op_Multiply
then
1201 Result
:= Left_Real
* Right_Real
;
1203 else pragma Assert
(Nkind
(N
) = N_Op_Divide
);
1204 if UR_Is_Zero
(Right_Real
) then
1205 Apply_Compile_Time_Constraint_Error
1206 (N
, "division by zero", CE_Divide_By_Zero
);
1210 Result
:= Left_Real
/ Right_Real
;
1213 Fold_Ureal
(N
, Result
, Stat
);
1216 end Eval_Arithmetic_Op
;
1218 ----------------------------
1219 -- Eval_Character_Literal --
1220 ----------------------------
1222 -- Nothing to be done!
1224 procedure Eval_Character_Literal
(N
: Node_Id
) is
1225 pragma Warnings
(Off
, N
);
1228 end Eval_Character_Literal
;
1234 -- Static function calls are either calls to predefined operators
1235 -- with static arguments, or calls to functions that rename a literal.
1236 -- Only the latter case is handled here, predefined operators are
1237 -- constant-folded elsewhere.
1238 -- If the function is itself inherited (see 7423-001) the literal of
1239 -- the parent type must be explicitly converted to the return type
1242 procedure Eval_Call
(N
: Node_Id
) is
1243 Loc
: constant Source_Ptr
:= Sloc
(N
);
1244 Typ
: constant Entity_Id
:= Etype
(N
);
1248 if Nkind
(N
) = N_Function_Call
1249 and then No
(Parameter_Associations
(N
))
1250 and then Is_Entity_Name
(Name
(N
))
1251 and then Present
(Alias
(Entity
(Name
(N
))))
1252 and then Is_Enumeration_Type
(Base_Type
(Typ
))
1254 Lit
:= Alias
(Entity
(Name
(N
)));
1256 while Present
(Alias
(Lit
)) loop
1260 if Ekind
(Lit
) = E_Enumeration_Literal
then
1261 if Base_Type
(Etype
(Lit
)) /= Base_Type
(Typ
) then
1263 (N
, Convert_To
(Typ
, New_Occurrence_Of
(Lit
, Loc
)));
1265 Rewrite
(N
, New_Occurrence_Of
(Lit
, Loc
));
1273 ------------------------
1274 -- Eval_Concatenation --
1275 ------------------------
1277 -- Concatenation is a static function, so the result is static if
1278 -- both operands are static (RM 4.9(7), 4.9(21)).
1280 procedure Eval_Concatenation
(N
: Node_Id
) is
1281 Left
: constant Node_Id
:= Left_Opnd
(N
);
1282 Right
: constant Node_Id
:= Right_Opnd
(N
);
1283 C_Typ
: constant Entity_Id
:= Root_Type
(Component_Type
(Etype
(N
)));
1288 -- Concatenation is never static in Ada 83, so if Ada 83
1289 -- check operand non-static context
1291 if Ada_Version
= Ada_83
1292 and then Comes_From_Source
(N
)
1294 Check_Non_Static_Context
(Left
);
1295 Check_Non_Static_Context
(Right
);
1299 -- If not foldable we are done. In principle concatenation that yields
1300 -- any string type is static (i.e. an array type of character types).
1301 -- However, character types can include enumeration literals, and
1302 -- concatenation in that case cannot be described by a literal, so we
1303 -- only consider the operation static if the result is an array of
1304 -- (a descendant of) a predefined character type.
1306 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
1308 if (C_Typ
= Standard_Character
1309 or else C_Typ
= Standard_Wide_Character
1310 or else C_Typ
= Standard_Wide_Wide_Character
)
1315 Set_Is_Static_Expression
(N
, False);
1319 -- Compile time string concatenation
1321 -- ??? Note that operands that are aggregates can be marked as
1322 -- static, so we should attempt at a later stage to fold
1323 -- concatenations with such aggregates.
1326 Left_Str
: constant Node_Id
:= Get_String_Val
(Left
);
1328 Right_Str
: constant Node_Id
:= Get_String_Val
(Right
);
1331 -- Establish new string literal, and store left operand. We make
1332 -- sure to use the special Start_String that takes an operand if
1333 -- the left operand is a string literal. Since this is optimized
1334 -- in the case where that is the most recently created string
1335 -- literal, we ensure efficient time/space behavior for the
1336 -- case of a concatenation of a series of string literals.
1338 if Nkind
(Left_Str
) = N_String_Literal
then
1339 Left_Len
:= String_Length
(Strval
(Left_Str
));
1340 Start_String
(Strval
(Left_Str
));
1343 Store_String_Char
(UI_To_CC
(Char_Literal_Value
(Left_Str
)));
1347 -- Now append the characters of the right operand
1349 if Nkind
(Right_Str
) = N_String_Literal
then
1351 S
: constant String_Id
:= Strval
(Right_Str
);
1354 for J
in 1 .. String_Length
(S
) loop
1355 Store_String_Char
(Get_String_Char
(S
, J
));
1359 Store_String_Char
(UI_To_CC
(Char_Literal_Value
(Right_Str
)));
1362 Set_Is_Static_Expression
(N
, Stat
);
1366 -- If left operand is the empty string, the result is the
1367 -- right operand, including its bounds if anomalous.
1370 and then Is_Array_Type
(Etype
(Right
))
1371 and then Etype
(Right
) /= Any_String
1373 Set_Etype
(N
, Etype
(Right
));
1376 Fold_Str
(N
, End_String
, True);
1379 end Eval_Concatenation
;
1381 ---------------------------------
1382 -- Eval_Conditional_Expression --
1383 ---------------------------------
1385 -- This GNAT internal construct can never be statically folded, so the
1386 -- only required processing is to do the check for non-static context
1387 -- for the two expression operands.
1389 procedure Eval_Conditional_Expression
(N
: Node_Id
) is
1390 Condition
: constant Node_Id
:= First
(Expressions
(N
));
1391 Then_Expr
: constant Node_Id
:= Next
(Condition
);
1392 Else_Expr
: constant Node_Id
:= Next
(Then_Expr
);
1395 Check_Non_Static_Context
(Then_Expr
);
1396 Check_Non_Static_Context
(Else_Expr
);
1397 end Eval_Conditional_Expression
;
1399 ----------------------
1400 -- Eval_Entity_Name --
1401 ----------------------
1403 -- This procedure is used for identifiers and expanded names other than
1404 -- named numbers (see Eval_Named_Integer, Eval_Named_Real. These are
1405 -- static if they denote a static constant (RM 4.9(6)) or if the name
1406 -- denotes an enumeration literal (RM 4.9(22)).
1408 procedure Eval_Entity_Name
(N
: Node_Id
) is
1409 Def_Id
: constant Entity_Id
:= Entity
(N
);
1413 -- Enumeration literals are always considered to be constants
1414 -- and cannot raise constraint error (RM 4.9(22)).
1416 if Ekind
(Def_Id
) = E_Enumeration_Literal
then
1417 Set_Is_Static_Expression
(N
);
1420 -- A name is static if it denotes a static constant (RM 4.9(5)), and
1421 -- we also copy Raise_Constraint_Error. Notice that even if non-static,
1422 -- it does not violate 10.2.1(8) here, since this is not a variable.
1424 elsif Ekind
(Def_Id
) = E_Constant
then
1426 -- Deferred constants must always be treated as nonstatic
1427 -- outside the scope of their full view.
1429 if Present
(Full_View
(Def_Id
))
1430 and then not In_Open_Scopes
(Scope
(Def_Id
))
1434 Val
:= Constant_Value
(Def_Id
);
1437 if Present
(Val
) then
1438 Set_Is_Static_Expression
1439 (N
, Is_Static_Expression
(Val
)
1440 and then Is_Static_Subtype
(Etype
(Def_Id
)));
1441 Set_Raises_Constraint_Error
(N
, Raises_Constraint_Error
(Val
));
1443 if not Is_Static_Expression
(N
)
1444 and then not Is_Generic_Type
(Etype
(N
))
1446 Validate_Static_Object_Name
(N
);
1453 -- Fall through if the name is not static
1455 Validate_Static_Object_Name
(N
);
1456 end Eval_Entity_Name
;
1458 ----------------------------
1459 -- Eval_Indexed_Component --
1460 ----------------------------
1462 -- Indexed components are never static, so we need to perform the check
1463 -- for non-static context on the index values. Then, we check if the
1464 -- value can be obtained at compile time, even though it is non-static.
1466 procedure Eval_Indexed_Component
(N
: Node_Id
) is
1470 -- Check for non-static context on index values
1472 Expr
:= First
(Expressions
(N
));
1473 while Present
(Expr
) loop
1474 Check_Non_Static_Context
(Expr
);
1478 -- If the indexed component appears in an object renaming declaration
1479 -- then we do not want to try to evaluate it, since in this case we
1480 -- need the identity of the array element.
1482 if Nkind
(Parent
(N
)) = N_Object_Renaming_Declaration
then
1485 -- Similarly if the indexed component appears as the prefix of an
1486 -- attribute we don't want to evaluate it, because at least for
1487 -- some cases of attributes we need the identify (e.g. Access, Size)
1489 elsif Nkind
(Parent
(N
)) = N_Attribute_Reference
then
1493 -- Note: there are other cases, such as the left side of an assignment,
1494 -- or an OUT parameter for a call, where the replacement results in the
1495 -- illegal use of a constant, But these cases are illegal in the first
1496 -- place, so the replacement, though silly, is harmless.
1498 -- Now see if this is a constant array reference
1500 if List_Length
(Expressions
(N
)) = 1
1501 and then Is_Entity_Name
(Prefix
(N
))
1502 and then Ekind
(Entity
(Prefix
(N
))) = E_Constant
1503 and then Present
(Constant_Value
(Entity
(Prefix
(N
))))
1506 Loc
: constant Source_Ptr
:= Sloc
(N
);
1507 Arr
: constant Node_Id
:= Constant_Value
(Entity
(Prefix
(N
)));
1508 Sub
: constant Node_Id
:= First
(Expressions
(N
));
1514 -- Linear one's origin subscript value for array reference
1517 -- Lower bound of the first array index
1520 -- Value from constant array
1523 Atyp
:= Etype
(Arr
);
1525 if Is_Access_Type
(Atyp
) then
1526 Atyp
:= Designated_Type
(Atyp
);
1529 -- If we have an array type (we should have but perhaps there
1530 -- are error cases where this is not the case), then see if we
1531 -- can do a constant evaluation of the array reference.
1533 if Is_Array_Type
(Atyp
) then
1534 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
1535 Lbd
:= String_Literal_Low_Bound
(Atyp
);
1537 Lbd
:= Type_Low_Bound
(Etype
(First_Index
(Atyp
)));
1540 if Compile_Time_Known_Value
(Sub
)
1541 and then Nkind
(Arr
) = N_Aggregate
1542 and then Compile_Time_Known_Value
(Lbd
)
1543 and then Is_Discrete_Type
(Component_Type
(Atyp
))
1545 Lin
:= UI_To_Int
(Expr_Value
(Sub
) - Expr_Value
(Lbd
)) + 1;
1547 if List_Length
(Expressions
(Arr
)) >= Lin
then
1548 Elm
:= Pick
(Expressions
(Arr
), Lin
);
1550 -- If the resulting expression is compile time known,
1551 -- then we can rewrite the indexed component with this
1552 -- value, being sure to mark the result as non-static.
1553 -- We also reset the Sloc, in case this generates an
1554 -- error later on (e.g. 136'Access).
1556 if Compile_Time_Known_Value
(Elm
) then
1557 Rewrite
(N
, Duplicate_Subexpr_No_Checks
(Elm
));
1558 Set_Is_Static_Expression
(N
, False);
1566 end Eval_Indexed_Component
;
1568 --------------------------
1569 -- Eval_Integer_Literal --
1570 --------------------------
1572 -- Numeric literals are static (RM 4.9(1)), and have already been marked
1573 -- as static by the analyzer. The reason we did it that early is to allow
1574 -- the possibility of turning off the Is_Static_Expression flag after
1575 -- analysis, but before resolution, when integer literals are generated
1576 -- in the expander that do not correspond to static expressions.
1578 procedure Eval_Integer_Literal
(N
: Node_Id
) is
1579 T
: constant Entity_Id
:= Etype
(N
);
1581 function In_Any_Integer_Context
return Boolean;
1582 -- If the literal is resolved with a specific type in a context
1583 -- where the expected type is Any_Integer, there are no range checks
1584 -- on the literal. By the time the literal is evaluated, it carries
1585 -- the type imposed by the enclosing expression, and we must recover
1586 -- the context to determine that Any_Integer is meant.
1588 ----------------------------
1589 -- To_Any_Integer_Context --
1590 ----------------------------
1592 function In_Any_Integer_Context
return Boolean is
1593 Par
: constant Node_Id
:= Parent
(N
);
1594 K
: constant Node_Kind
:= Nkind
(Par
);
1597 -- Any_Integer also appears in digits specifications for real types,
1598 -- but those have bounds smaller that those of any integer base
1599 -- type, so we can safely ignore these cases.
1601 return K
= N_Number_Declaration
1602 or else K
= N_Attribute_Reference
1603 or else K
= N_Attribute_Definition_Clause
1604 or else K
= N_Modular_Type_Definition
1605 or else K
= N_Signed_Integer_Type_Definition
;
1606 end In_Any_Integer_Context
;
1608 -- Start of processing for Eval_Integer_Literal
1612 -- If the literal appears in a non-expression context, then it is
1613 -- certainly appearing in a non-static context, so check it. This
1614 -- is actually a redundant check, since Check_Non_Static_Context
1615 -- would check it, but it seems worth while avoiding the call.
1617 if Nkind
(Parent
(N
)) not in N_Subexpr
1618 and then not In_Any_Integer_Context
1620 Check_Non_Static_Context
(N
);
1623 -- Modular integer literals must be in their base range
1625 if Is_Modular_Integer_Type
(T
)
1626 and then Is_Out_Of_Range
(N
, Base_Type
(T
))
1630 end Eval_Integer_Literal
;
1632 ---------------------
1633 -- Eval_Logical_Op --
1634 ---------------------
1636 -- Logical operations are static functions, so the result is potentially
1637 -- static if both operands are potentially static (RM 4.9(7), 4.9(20)).
1639 procedure Eval_Logical_Op
(N
: Node_Id
) is
1640 Left
: constant Node_Id
:= Left_Opnd
(N
);
1641 Right
: constant Node_Id
:= Right_Opnd
(N
);
1646 -- If not foldable we are done
1648 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
1654 -- Compile time evaluation of logical operation
1657 Left_Int
: constant Uint
:= Expr_Value
(Left
);
1658 Right_Int
: constant Uint
:= Expr_Value
(Right
);
1661 if Is_Modular_Integer_Type
(Etype
(N
)) then
1663 Left_Bits
: Bits
(0 .. UI_To_Int
(Esize
(Etype
(N
))) - 1);
1664 Right_Bits
: Bits
(0 .. UI_To_Int
(Esize
(Etype
(N
))) - 1);
1667 To_Bits
(Left_Int
, Left_Bits
);
1668 To_Bits
(Right_Int
, Right_Bits
);
1670 -- Note: should really be able to use array ops instead of
1671 -- these loops, but they weren't working at the time ???
1673 if Nkind
(N
) = N_Op_And
then
1674 for J
in Left_Bits
'Range loop
1675 Left_Bits
(J
) := Left_Bits
(J
) and Right_Bits
(J
);
1678 elsif Nkind
(N
) = N_Op_Or
then
1679 for J
in Left_Bits
'Range loop
1680 Left_Bits
(J
) := Left_Bits
(J
) or Right_Bits
(J
);
1684 pragma Assert
(Nkind
(N
) = N_Op_Xor
);
1686 for J
in Left_Bits
'Range loop
1687 Left_Bits
(J
) := Left_Bits
(J
) xor Right_Bits
(J
);
1691 Fold_Uint
(N
, From_Bits
(Left_Bits
, Etype
(N
)), Stat
);
1695 pragma Assert
(Is_Boolean_Type
(Etype
(N
)));
1697 if Nkind
(N
) = N_Op_And
then
1699 Test
(Is_True
(Left_Int
) and then Is_True
(Right_Int
)), Stat
);
1701 elsif Nkind
(N
) = N_Op_Or
then
1703 Test
(Is_True
(Left_Int
) or else Is_True
(Right_Int
)), Stat
);
1706 pragma Assert
(Nkind
(N
) = N_Op_Xor
);
1708 Test
(Is_True
(Left_Int
) xor Is_True
(Right_Int
)), Stat
);
1712 end Eval_Logical_Op
;
1714 ------------------------
1715 -- Eval_Membership_Op --
1716 ------------------------
1718 -- A membership test is potentially static if the expression is static,
1719 -- and the range is a potentially static range, or is a subtype mark
1720 -- denoting a static subtype (RM 4.9(12)).
1722 procedure Eval_Membership_Op
(N
: Node_Id
) is
1723 Left
: constant Node_Id
:= Left_Opnd
(N
);
1724 Right
: constant Node_Id
:= Right_Opnd
(N
);
1733 -- Ignore if error in either operand, except to make sure that
1734 -- Any_Type is properly propagated to avoid junk cascaded errors.
1736 if Etype
(Left
) = Any_Type
1737 or else Etype
(Right
) = Any_Type
1739 Set_Etype
(N
, Any_Type
);
1743 -- Case of right operand is a subtype name
1745 if Is_Entity_Name
(Right
) then
1746 Def_Id
:= Entity
(Right
);
1748 if (Is_Scalar_Type
(Def_Id
) or else Is_String_Type
(Def_Id
))
1749 and then Is_OK_Static_Subtype
(Def_Id
)
1751 Test_Expression_Is_Foldable
(N
, Left
, Stat
, Fold
);
1753 if not Fold
or else not Stat
then
1757 Check_Non_Static_Context
(Left
);
1761 -- For string membership tests we will check the length
1764 if not Is_String_Type
(Def_Id
) then
1765 Lo
:= Type_Low_Bound
(Def_Id
);
1766 Hi
:= Type_High_Bound
(Def_Id
);
1773 -- Case of right operand is a range
1776 if Is_Static_Range
(Right
) then
1777 Test_Expression_Is_Foldable
(N
, Left
, Stat
, Fold
);
1779 if not Fold
or else not Stat
then
1782 -- If one bound of range raises CE, then don't try to fold
1784 elsif not Is_OK_Static_Range
(Right
) then
1785 Check_Non_Static_Context
(Left
);
1790 Check_Non_Static_Context
(Left
);
1794 -- Here we know range is an OK static range
1796 Lo
:= Low_Bound
(Right
);
1797 Hi
:= High_Bound
(Right
);
1800 -- For strings we check that the length of the string expression is
1801 -- compatible with the string subtype if the subtype is constrained,
1802 -- or if unconstrained then the test is always true.
1804 if Is_String_Type
(Etype
(Right
)) then
1805 if not Is_Constrained
(Etype
(Right
)) then
1810 Typlen
: constant Uint
:= String_Type_Len
(Etype
(Right
));
1811 Strlen
: constant Uint
:=
1812 UI_From_Int
(String_Length
(Strval
(Get_String_Val
(Left
))));
1814 Result
:= (Typlen
= Strlen
);
1818 -- Fold the membership test. We know we have a static range and Lo
1819 -- and Hi are set to the expressions for the end points of this range.
1821 elsif Is_Real_Type
(Etype
(Right
)) then
1823 Leftval
: constant Ureal
:= Expr_Value_R
(Left
);
1826 Result
:= Expr_Value_R
(Lo
) <= Leftval
1827 and then Leftval
<= Expr_Value_R
(Hi
);
1832 Leftval
: constant Uint
:= Expr_Value
(Left
);
1835 Result
:= Expr_Value
(Lo
) <= Leftval
1836 and then Leftval
<= Expr_Value
(Hi
);
1840 if Nkind
(N
) = N_Not_In
then
1841 Result
:= not Result
;
1844 Fold_Uint
(N
, Test
(Result
), True);
1845 Warn_On_Known_Condition
(N
);
1846 end Eval_Membership_Op
;
1848 ------------------------
1849 -- Eval_Named_Integer --
1850 ------------------------
1852 procedure Eval_Named_Integer
(N
: Node_Id
) is
1855 Expr_Value
(Expression
(Declaration_Node
(Entity
(N
)))), True);
1856 end Eval_Named_Integer
;
1858 ---------------------
1859 -- Eval_Named_Real --
1860 ---------------------
1862 procedure Eval_Named_Real
(N
: Node_Id
) is
1865 Expr_Value_R
(Expression
(Declaration_Node
(Entity
(N
)))), True);
1866 end Eval_Named_Real
;
1872 -- Exponentiation is a static functions, so the result is potentially
1873 -- static if both operands are potentially static (RM 4.9(7), 4.9(20)).
1875 procedure Eval_Op_Expon
(N
: Node_Id
) is
1876 Left
: constant Node_Id
:= Left_Opnd
(N
);
1877 Right
: constant Node_Id
:= Right_Opnd
(N
);
1882 -- If not foldable we are done
1884 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
1890 -- Fold exponentiation operation
1893 Right_Int
: constant Uint
:= Expr_Value
(Right
);
1898 if Is_Integer_Type
(Etype
(Left
)) then
1900 Left_Int
: constant Uint
:= Expr_Value
(Left
);
1904 -- Exponentiation of an integer raises the exception
1905 -- Constraint_Error for a negative exponent (RM 4.5.6)
1907 if Right_Int
< 0 then
1908 Apply_Compile_Time_Constraint_Error
1909 (N
, "integer exponent negative",
1910 CE_Range_Check_Failed
,
1915 if OK_Bits
(N
, Num_Bits
(Left_Int
) * Right_Int
) then
1916 Result
:= Left_Int
** Right_Int
;
1921 if Is_Modular_Integer_Type
(Etype
(N
)) then
1922 Result
:= Result
mod Modulus
(Etype
(N
));
1925 Fold_Uint
(N
, Result
, Stat
);
1933 Left_Real
: constant Ureal
:= Expr_Value_R
(Left
);
1936 -- Cannot have a zero base with a negative exponent
1938 if UR_Is_Zero
(Left_Real
) then
1940 if Right_Int
< 0 then
1941 Apply_Compile_Time_Constraint_Error
1942 (N
, "zero ** negative integer",
1943 CE_Range_Check_Failed
,
1947 Fold_Ureal
(N
, Ureal_0
, Stat
);
1951 Fold_Ureal
(N
, Left_Real
** Right_Int
, Stat
);
1962 -- The not operation is a static functions, so the result is potentially
1963 -- static if the operand is potentially static (RM 4.9(7), 4.9(20)).
1965 procedure Eval_Op_Not
(N
: Node_Id
) is
1966 Right
: constant Node_Id
:= Right_Opnd
(N
);
1971 -- If not foldable we are done
1973 Test_Expression_Is_Foldable
(N
, Right
, Stat
, Fold
);
1979 -- Fold not operation
1982 Rint
: constant Uint
:= Expr_Value
(Right
);
1983 Typ
: constant Entity_Id
:= Etype
(N
);
1986 -- Negation is equivalent to subtracting from the modulus minus
1987 -- one. For a binary modulus this is equivalent to the ones-
1988 -- component of the original value. For non-binary modulus this
1989 -- is an arbitrary but consistent definition.
1991 if Is_Modular_Integer_Type
(Typ
) then
1992 Fold_Uint
(N
, Modulus
(Typ
) - 1 - Rint
, Stat
);
1995 pragma Assert
(Is_Boolean_Type
(Typ
));
1996 Fold_Uint
(N
, Test
(not Is_True
(Rint
)), Stat
);
1999 Set_Is_Static_Expression
(N
, Stat
);
2003 -------------------------------
2004 -- Eval_Qualified_Expression --
2005 -------------------------------
2007 -- A qualified expression is potentially static if its subtype mark denotes
2008 -- a static subtype and its expression is potentially static (RM 4.9 (11)).
2010 procedure Eval_Qualified_Expression
(N
: Node_Id
) is
2011 Operand
: constant Node_Id
:= Expression
(N
);
2012 Target_Type
: constant Entity_Id
:= Entity
(Subtype_Mark
(N
));
2019 -- Can only fold if target is string or scalar and subtype is static
2020 -- Also, do not fold if our parent is an allocator (this is because
2021 -- the qualified expression is really part of the syntactic structure
2022 -- of an allocator, and we do not want to end up with something that
2023 -- corresponds to "new 1" where the 1 is the result of folding a
2024 -- qualified expression).
2026 if not Is_Static_Subtype
(Target_Type
)
2027 or else Nkind
(Parent
(N
)) = N_Allocator
2029 Check_Non_Static_Context
(Operand
);
2031 -- If operand is known to raise constraint_error, set the
2032 -- flag on the expression so it does not get optimized away.
2034 if Nkind
(Operand
) = N_Raise_Constraint_Error
then
2035 Set_Raises_Constraint_Error
(N
);
2041 -- If not foldable we are done
2043 Test_Expression_Is_Foldable
(N
, Operand
, Stat
, Fold
);
2048 -- Don't try fold if target type has constraint error bounds
2050 elsif not Is_OK_Static_Subtype
(Target_Type
) then
2051 Set_Raises_Constraint_Error
(N
);
2055 -- Here we will fold, save Print_In_Hex indication
2057 Hex
:= Nkind
(Operand
) = N_Integer_Literal
2058 and then Print_In_Hex
(Operand
);
2060 -- Fold the result of qualification
2062 if Is_Discrete_Type
(Target_Type
) then
2063 Fold_Uint
(N
, Expr_Value
(Operand
), Stat
);
2065 -- Preserve Print_In_Hex indication
2067 if Hex
and then Nkind
(N
) = N_Integer_Literal
then
2068 Set_Print_In_Hex
(N
);
2071 elsif Is_Real_Type
(Target_Type
) then
2072 Fold_Ureal
(N
, Expr_Value_R
(Operand
), Stat
);
2075 Fold_Str
(N
, Strval
(Get_String_Val
(Operand
)), Stat
);
2078 Set_Is_Static_Expression
(N
, False);
2080 Check_String_Literal_Length
(N
, Target_Type
);
2086 -- The expression may be foldable but not static
2088 Set_Is_Static_Expression
(N
, Stat
);
2090 if Is_Out_Of_Range
(N
, Etype
(N
)) then
2093 end Eval_Qualified_Expression
;
2095 -----------------------
2096 -- Eval_Real_Literal --
2097 -----------------------
2099 -- Numeric literals are static (RM 4.9(1)), and have already been marked
2100 -- as static by the analyzer. The reason we did it that early is to allow
2101 -- the possibility of turning off the Is_Static_Expression flag after
2102 -- analysis, but before resolution, when integer literals are generated
2103 -- in the expander that do not correspond to static expressions.
2105 procedure Eval_Real_Literal
(N
: Node_Id
) is
2107 -- If the literal appears in a non-expression context, then it is
2108 -- certainly appearing in a non-static context, so check it.
2110 if Nkind
(Parent
(N
)) not in N_Subexpr
then
2111 Check_Non_Static_Context
(N
);
2114 end Eval_Real_Literal
;
2116 ------------------------
2117 -- Eval_Relational_Op --
2118 ------------------------
2120 -- Relational operations are static functions, so the result is static
2121 -- if both operands are static (RM 4.9(7), 4.9(20)).
2123 procedure Eval_Relational_Op
(N
: Node_Id
) is
2124 Left
: constant Node_Id
:= Left_Opnd
(N
);
2125 Right
: constant Node_Id
:= Right_Opnd
(N
);
2126 Typ
: constant Entity_Id
:= Etype
(Left
);
2132 -- One special case to deal with first. If we can tell that
2133 -- the result will be false because the lengths of one or
2134 -- more index subtypes are compile time known and different,
2135 -- then we can replace the entire result by False. We only
2136 -- do this for one dimensional arrays, because the case of
2137 -- multi-dimensional arrays is rare and too much trouble!
2139 if Is_Array_Type
(Typ
)
2140 and then Number_Dimensions
(Typ
) = 1
2141 and then (Nkind
(N
) = N_Op_Eq
2142 or else Nkind
(N
) = N_Op_Ne
)
2144 if Raises_Constraint_Error
(Left
)
2145 or else Raises_Constraint_Error
(Right
)
2151 procedure Get_Static_Length
(Op
: Node_Id
; Len
: out Uint
);
2152 -- If Op is an expression for a constrained array with a
2153 -- known at compile time length, then Len is set to this
2154 -- (non-negative length). Otherwise Len is set to minus 1.
2156 -----------------------
2157 -- Get_Static_Length --
2158 -----------------------
2160 procedure Get_Static_Length
(Op
: Node_Id
; Len
: out Uint
) is
2164 if Nkind
(Op
) = N_String_Literal
then
2165 Len
:= UI_From_Int
(String_Length
(Strval
(Op
)));
2167 elsif not Is_Constrained
(Etype
(Op
)) then
2168 Len
:= Uint_Minus_1
;
2171 T
:= Etype
(First_Index
(Etype
(Op
)));
2173 if Is_Discrete_Type
(T
)
2175 Compile_Time_Known_Value
(Type_Low_Bound
(T
))
2177 Compile_Time_Known_Value
(Type_High_Bound
(T
))
2179 Len
:= UI_Max
(Uint_0
,
2180 Expr_Value
(Type_High_Bound
(T
)) -
2181 Expr_Value
(Type_Low_Bound
(T
)) + 1);
2183 Len
:= Uint_Minus_1
;
2186 end Get_Static_Length
;
2192 Get_Static_Length
(Left
, Len_L
);
2193 Get_Static_Length
(Right
, Len_R
);
2195 if Len_L
/= Uint_Minus_1
2196 and then Len_R
/= Uint_Minus_1
2197 and then Len_L
/= Len_R
2199 Fold_Uint
(N
, Test
(Nkind
(N
) = N_Op_Ne
), False);
2200 Warn_On_Known_Condition
(N
);
2205 -- Another special case: comparisons against null for pointers that
2206 -- are known to be non-null. This is useful when migrating from Ada95
2207 -- code when non-null restrictions are added to type declarations and
2208 -- parameter specifications.
2210 elsif Is_Access_Type
(Typ
)
2211 and then Comes_From_Source
(N
)
2213 ((Is_Entity_Name
(Left
)
2214 and then Is_Known_Non_Null
(Entity
(Left
))
2215 and then Nkind
(Right
) = N_Null
)
2217 (Is_Entity_Name
(Right
)
2218 and then Is_Known_Non_Null
(Entity
(Right
))
2219 and then Nkind
(Left
) = N_Null
))
2221 Fold_Uint
(N
, Test
(Nkind
(N
) = N_Op_Ne
), False);
2222 Warn_On_Known_Condition
(N
);
2226 -- Can only fold if type is scalar (don't fold string ops)
2228 if not Is_Scalar_Type
(Typ
) then
2229 Check_Non_Static_Context
(Left
);
2230 Check_Non_Static_Context
(Right
);
2234 -- If not foldable we are done
2236 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
2242 -- Integer and Enumeration (discrete) type cases
2244 if Is_Discrete_Type
(Typ
) then
2246 Left_Int
: constant Uint
:= Expr_Value
(Left
);
2247 Right_Int
: constant Uint
:= Expr_Value
(Right
);
2251 when N_Op_Eq
=> Result
:= Left_Int
= Right_Int
;
2252 when N_Op_Ne
=> Result
:= Left_Int
/= Right_Int
;
2253 when N_Op_Lt
=> Result
:= Left_Int
< Right_Int
;
2254 when N_Op_Le
=> Result
:= Left_Int
<= Right_Int
;
2255 when N_Op_Gt
=> Result
:= Left_Int
> Right_Int
;
2256 when N_Op_Ge
=> Result
:= Left_Int
>= Right_Int
;
2259 raise Program_Error
;
2262 Fold_Uint
(N
, Test
(Result
), Stat
);
2268 pragma Assert
(Is_Real_Type
(Typ
));
2271 Left_Real
: constant Ureal
:= Expr_Value_R
(Left
);
2272 Right_Real
: constant Ureal
:= Expr_Value_R
(Right
);
2276 when N_Op_Eq
=> Result
:= (Left_Real
= Right_Real
);
2277 when N_Op_Ne
=> Result
:= (Left_Real
/= Right_Real
);
2278 when N_Op_Lt
=> Result
:= (Left_Real
< Right_Real
);
2279 when N_Op_Le
=> Result
:= (Left_Real
<= Right_Real
);
2280 when N_Op_Gt
=> Result
:= (Left_Real
> Right_Real
);
2281 when N_Op_Ge
=> Result
:= (Left_Real
>= Right_Real
);
2284 raise Program_Error
;
2287 Fold_Uint
(N
, Test
(Result
), Stat
);
2291 Warn_On_Known_Condition
(N
);
2292 end Eval_Relational_Op
;
2298 -- Shift operations are intrinsic operations that can never be static,
2299 -- so the only processing required is to perform the required check for
2300 -- a non static context for the two operands.
2302 -- Actually we could do some compile time evaluation here some time ???
2304 procedure Eval_Shift
(N
: Node_Id
) is
2306 Check_Non_Static_Context
(Left_Opnd
(N
));
2307 Check_Non_Static_Context
(Right_Opnd
(N
));
2310 ------------------------
2311 -- Eval_Short_Circuit --
2312 ------------------------
2314 -- A short circuit operation is potentially static if both operands
2315 -- are potentially static (RM 4.9 (13))
2317 procedure Eval_Short_Circuit
(N
: Node_Id
) is
2318 Kind
: constant Node_Kind
:= Nkind
(N
);
2319 Left
: constant Node_Id
:= Left_Opnd
(N
);
2320 Right
: constant Node_Id
:= Right_Opnd
(N
);
2322 Rstat
: constant Boolean :=
2323 Is_Static_Expression
(Left
)
2324 and then Is_Static_Expression
(Right
);
2327 -- Short circuit operations are never static in Ada 83
2329 if Ada_Version
= Ada_83
2330 and then Comes_From_Source
(N
)
2332 Check_Non_Static_Context
(Left
);
2333 Check_Non_Static_Context
(Right
);
2337 -- Now look at the operands, we can't quite use the normal call to
2338 -- Test_Expression_Is_Foldable here because short circuit operations
2339 -- are a special case, they can still be foldable, even if the right
2340 -- operand raises constraint error.
2342 -- If either operand is Any_Type, just propagate to result and
2343 -- do not try to fold, this prevents cascaded errors.
2345 if Etype
(Left
) = Any_Type
or else Etype
(Right
) = Any_Type
then
2346 Set_Etype
(N
, Any_Type
);
2349 -- If left operand raises constraint error, then replace node N with
2350 -- the raise constraint error node, and we are obviously not foldable.
2351 -- Is_Static_Expression is set from the two operands in the normal way,
2352 -- and we check the right operand if it is in a non-static context.
2354 elsif Raises_Constraint_Error
(Left
) then
2356 Check_Non_Static_Context
(Right
);
2359 Rewrite_In_Raise_CE
(N
, Left
);
2360 Set_Is_Static_Expression
(N
, Rstat
);
2363 -- If the result is not static, then we won't in any case fold
2365 elsif not Rstat
then
2366 Check_Non_Static_Context
(Left
);
2367 Check_Non_Static_Context
(Right
);
2371 -- Here the result is static, note that, unlike the normal processing
2372 -- in Test_Expression_Is_Foldable, we did *not* check above to see if
2373 -- the right operand raises constraint error, that's because it is not
2374 -- significant if the left operand is decisive.
2376 Set_Is_Static_Expression
(N
);
2378 -- It does not matter if the right operand raises constraint error if
2379 -- it will not be evaluated. So deal specially with the cases where
2380 -- the right operand is not evaluated. Note that we will fold these
2381 -- cases even if the right operand is non-static, which is fine, but
2382 -- of course in these cases the result is not potentially static.
2384 Left_Int
:= Expr_Value
(Left
);
2386 if (Kind
= N_And_Then
and then Is_False
(Left_Int
))
2387 or else (Kind
= N_Or_Else
and Is_True
(Left_Int
))
2389 Fold_Uint
(N
, Left_Int
, Rstat
);
2393 -- If first operand not decisive, then it does matter if the right
2394 -- operand raises constraint error, since it will be evaluated, so
2395 -- we simply replace the node with the right operand. Note that this
2396 -- properly propagates Is_Static_Expression and Raises_Constraint_Error
2397 -- (both are set to True in Right).
2399 if Raises_Constraint_Error
(Right
) then
2400 Rewrite_In_Raise_CE
(N
, Right
);
2401 Check_Non_Static_Context
(Left
);
2405 -- Otherwise the result depends on the right operand
2407 Fold_Uint
(N
, Expr_Value
(Right
), Rstat
);
2409 end Eval_Short_Circuit
;
2415 -- Slices can never be static, so the only processing required is to
2416 -- check for non-static context if an explicit range is given.
2418 procedure Eval_Slice
(N
: Node_Id
) is
2419 Drange
: constant Node_Id
:= Discrete_Range
(N
);
2422 if Nkind
(Drange
) = N_Range
then
2423 Check_Non_Static_Context
(Low_Bound
(Drange
));
2424 Check_Non_Static_Context
(High_Bound
(Drange
));
2428 -------------------------
2429 -- Eval_String_Literal --
2430 -------------------------
2432 procedure Eval_String_Literal
(N
: Node_Id
) is
2433 Typ
: constant Entity_Id
:= Etype
(N
);
2434 Bas
: constant Entity_Id
:= Base_Type
(Typ
);
2440 -- Nothing to do if error type (handles cases like default expressions
2441 -- or generics where we have not yet fully resolved the type)
2443 if Bas
= Any_Type
or else Bas
= Any_String
then
2447 -- String literals are static if the subtype is static (RM 4.9(2)), so
2448 -- reset the static expression flag (it was set unconditionally in
2449 -- Analyze_String_Literal) if the subtype is non-static. We tell if
2450 -- the subtype is static by looking at the lower bound.
2452 if Ekind
(Typ
) = E_String_Literal_Subtype
then
2453 if not Is_OK_Static_Expression
(String_Literal_Low_Bound
(Typ
)) then
2454 Set_Is_Static_Expression
(N
, False);
2458 -- Here if Etype of string literal is normal Etype (not yet possible,
2459 -- but may be possible in future!)
2461 elsif not Is_OK_Static_Expression
2462 (Type_Low_Bound
(Etype
(First_Index
(Typ
))))
2464 Set_Is_Static_Expression
(N
, False);
2468 -- If original node was a type conversion, then result if non-static
2470 if Nkind
(Original_Node
(N
)) = N_Type_Conversion
then
2471 Set_Is_Static_Expression
(N
, False);
2475 -- Test for illegal Ada 95 cases. A string literal is illegal in
2476 -- Ada 95 if its bounds are outside the index base type and this
2477 -- index type is static. This can happen in only two ways. Either
2478 -- the string literal is too long, or it is null, and the lower
2479 -- bound is type'First. In either case it is the upper bound that
2480 -- is out of range of the index type.
2482 if Ada_Version
>= Ada_95
then
2483 if Root_Type
(Bas
) = Standard_String
2485 Root_Type
(Bas
) = Standard_Wide_String
2487 Xtp
:= Standard_Positive
;
2489 Xtp
:= Etype
(First_Index
(Bas
));
2492 if Ekind
(Typ
) = E_String_Literal_Subtype
then
2493 Lo
:= String_Literal_Low_Bound
(Typ
);
2495 Lo
:= Type_Low_Bound
(Etype
(First_Index
(Typ
)));
2498 Len
:= String_Length
(Strval
(N
));
2500 if UI_From_Int
(Len
) > String_Type_Len
(Bas
) then
2501 Apply_Compile_Time_Constraint_Error
2502 (N
, "string literal too long for}", CE_Length_Check_Failed
,
2504 Typ
=> First_Subtype
(Bas
));
2507 and then not Is_Generic_Type
(Xtp
)
2509 Expr_Value
(Lo
) = Expr_Value
(Type_Low_Bound
(Base_Type
(Xtp
)))
2511 Apply_Compile_Time_Constraint_Error
2512 (N
, "null string literal not allowed for}",
2513 CE_Length_Check_Failed
,
2515 Typ
=> First_Subtype
(Bas
));
2518 end Eval_String_Literal
;
2520 --------------------------
2521 -- Eval_Type_Conversion --
2522 --------------------------
2524 -- A type conversion is potentially static if its subtype mark is for a
2525 -- static scalar subtype, and its operand expression is potentially static
2528 procedure Eval_Type_Conversion
(N
: Node_Id
) is
2529 Operand
: constant Node_Id
:= Expression
(N
);
2530 Source_Type
: constant Entity_Id
:= Etype
(Operand
);
2531 Target_Type
: constant Entity_Id
:= Etype
(N
);
2536 function To_Be_Treated_As_Integer
(T
: Entity_Id
) return Boolean;
2537 -- Returns true if type T is an integer type, or if it is a
2538 -- fixed-point type to be treated as an integer (i.e. the flag
2539 -- Conversion_OK is set on the conversion node).
2541 function To_Be_Treated_As_Real
(T
: Entity_Id
) return Boolean;
2542 -- Returns true if type T is a floating-point type, or if it is a
2543 -- fixed-point type that is not to be treated as an integer (i.e. the
2544 -- flag Conversion_OK is not set on the conversion node).
2546 ------------------------------
2547 -- To_Be_Treated_As_Integer --
2548 ------------------------------
2550 function To_Be_Treated_As_Integer
(T
: Entity_Id
) return Boolean is
2554 or else (Is_Fixed_Point_Type
(T
) and then Conversion_OK
(N
));
2555 end To_Be_Treated_As_Integer
;
2557 ---------------------------
2558 -- To_Be_Treated_As_Real --
2559 ---------------------------
2561 function To_Be_Treated_As_Real
(T
: Entity_Id
) return Boolean is
2564 Is_Floating_Point_Type
(T
)
2565 or else (Is_Fixed_Point_Type
(T
) and then not Conversion_OK
(N
));
2566 end To_Be_Treated_As_Real
;
2568 -- Start of processing for Eval_Type_Conversion
2571 -- Cannot fold if target type is non-static or if semantic error
2573 if not Is_Static_Subtype
(Target_Type
) then
2574 Check_Non_Static_Context
(Operand
);
2577 elsif Error_Posted
(N
) then
2581 -- If not foldable we are done
2583 Test_Expression_Is_Foldable
(N
, Operand
, Stat
, Fold
);
2588 -- Don't try fold if target type has constraint error bounds
2590 elsif not Is_OK_Static_Subtype
(Target_Type
) then
2591 Set_Raises_Constraint_Error
(N
);
2595 -- Remaining processing depends on operand types. Note that in the
2596 -- following type test, fixed-point counts as real unless the flag
2597 -- Conversion_OK is set, in which case it counts as integer.
2599 -- Fold conversion, case of string type. The result is not static
2601 if Is_String_Type
(Target_Type
) then
2602 Fold_Str
(N
, Strval
(Get_String_Val
(Operand
)), False);
2606 -- Fold conversion, case of integer target type
2608 elsif To_Be_Treated_As_Integer
(Target_Type
) then
2613 -- Integer to integer conversion
2615 if To_Be_Treated_As_Integer
(Source_Type
) then
2616 Result
:= Expr_Value
(Operand
);
2618 -- Real to integer conversion
2621 Result
:= UR_To_Uint
(Expr_Value_R
(Operand
));
2624 -- If fixed-point type (Conversion_OK must be set), then the
2625 -- result is logically an integer, but we must replace the
2626 -- conversion with the corresponding real literal, since the
2627 -- type from a semantic point of view is still fixed-point.
2629 if Is_Fixed_Point_Type
(Target_Type
) then
2631 (N
, UR_From_Uint
(Result
) * Small_Value
(Target_Type
), Stat
);
2633 -- Otherwise result is integer literal
2636 Fold_Uint
(N
, Result
, Stat
);
2640 -- Fold conversion, case of real target type
2642 elsif To_Be_Treated_As_Real
(Target_Type
) then
2647 if To_Be_Treated_As_Real
(Source_Type
) then
2648 Result
:= Expr_Value_R
(Operand
);
2650 Result
:= UR_From_Uint
(Expr_Value
(Operand
));
2653 Fold_Ureal
(N
, Result
, Stat
);
2656 -- Enumeration types
2659 Fold_Uint
(N
, Expr_Value
(Operand
), Stat
);
2662 if Is_Out_Of_Range
(N
, Etype
(N
)) then
2666 end Eval_Type_Conversion
;
2672 -- Predefined unary operators are static functions (RM 4.9(20)) and thus
2673 -- are potentially static if the operand is potentially static (RM 4.9(7))
2675 procedure Eval_Unary_Op
(N
: Node_Id
) is
2676 Right
: constant Node_Id
:= Right_Opnd
(N
);
2681 -- If not foldable we are done
2683 Test_Expression_Is_Foldable
(N
, Right
, Stat
, Fold
);
2689 -- Fold for integer case
2691 if Is_Integer_Type
(Etype
(N
)) then
2693 Rint
: constant Uint
:= Expr_Value
(Right
);
2697 -- In the case of modular unary plus and abs there is no need
2698 -- to adjust the result of the operation since if the original
2699 -- operand was in bounds the result will be in the bounds of the
2700 -- modular type. However, in the case of modular unary minus the
2701 -- result may go out of the bounds of the modular type and needs
2704 if Nkind
(N
) = N_Op_Plus
then
2707 elsif Nkind
(N
) = N_Op_Minus
then
2708 if Is_Modular_Integer_Type
(Etype
(N
)) then
2709 Result
:= (-Rint
) mod Modulus
(Etype
(N
));
2715 pragma Assert
(Nkind
(N
) = N_Op_Abs
);
2719 Fold_Uint
(N
, Result
, Stat
);
2722 -- Fold for real case
2724 elsif Is_Real_Type
(Etype
(N
)) then
2726 Rreal
: constant Ureal
:= Expr_Value_R
(Right
);
2730 if Nkind
(N
) = N_Op_Plus
then
2733 elsif Nkind
(N
) = N_Op_Minus
then
2734 Result
:= UR_Negate
(Rreal
);
2737 pragma Assert
(Nkind
(N
) = N_Op_Abs
);
2738 Result
:= abs Rreal
;
2741 Fold_Ureal
(N
, Result
, Stat
);
2746 -------------------------------
2747 -- Eval_Unchecked_Conversion --
2748 -------------------------------
2750 -- Unchecked conversions can never be static, so the only required
2751 -- processing is to check for a non-static context for the operand.
2753 procedure Eval_Unchecked_Conversion
(N
: Node_Id
) is
2755 Check_Non_Static_Context
(Expression
(N
));
2756 end Eval_Unchecked_Conversion
;
2758 --------------------
2759 -- Expr_Rep_Value --
2760 --------------------
2762 function Expr_Rep_Value
(N
: Node_Id
) return Uint
is
2763 Kind
: constant Node_Kind
:= Nkind
(N
);
2767 if Is_Entity_Name
(N
) then
2770 -- An enumeration literal that was either in the source or
2771 -- created as a result of static evaluation.
2773 if Ekind
(Ent
) = E_Enumeration_Literal
then
2774 return Enumeration_Rep
(Ent
);
2776 -- A user defined static constant
2779 pragma Assert
(Ekind
(Ent
) = E_Constant
);
2780 return Expr_Rep_Value
(Constant_Value
(Ent
));
2783 -- An integer literal that was either in the source or created
2784 -- as a result of static evaluation.
2786 elsif Kind
= N_Integer_Literal
then
2789 -- A real literal for a fixed-point type. This must be the fixed-point
2790 -- case, either the literal is of a fixed-point type, or it is a bound
2791 -- of a fixed-point type, with type universal real. In either case we
2792 -- obtain the desired value from Corresponding_Integer_Value.
2794 elsif Kind
= N_Real_Literal
then
2795 pragma Assert
(Is_Fixed_Point_Type
(Underlying_Type
(Etype
(N
))));
2796 return Corresponding_Integer_Value
(N
);
2798 -- Peculiar VMS case, if we have xxx'Null_Parameter, return zero
2800 elsif Kind
= N_Attribute_Reference
2801 and then Attribute_Name
(N
) = Name_Null_Parameter
2805 -- Otherwise must be character literal
2808 pragma Assert
(Kind
= N_Character_Literal
);
2811 -- Since Character literals of type Standard.Character don't
2812 -- have any defining character literals built for them, they
2813 -- do not have their Entity set, so just use their Char
2814 -- code. Otherwise for user-defined character literals use
2815 -- their Pos value as usual which is the same as the Rep value.
2818 return Char_Literal_Value
(N
);
2820 return Enumeration_Rep
(Ent
);
2829 function Expr_Value
(N
: Node_Id
) return Uint
is
2830 Kind
: constant Node_Kind
:= Nkind
(N
);
2831 CV_Ent
: CV_Entry
renames CV_Cache
(Nat
(N
) mod CV_Cache_Size
);
2836 -- If already in cache, then we know it's compile time known and
2837 -- we can return the value that was previously stored in the cache
2838 -- since compile time known values cannot change :-)
2840 if CV_Ent
.N
= N
then
2844 -- Otherwise proceed to test value
2846 if Is_Entity_Name
(N
) then
2849 -- An enumeration literal that was either in the source or
2850 -- created as a result of static evaluation.
2852 if Ekind
(Ent
) = E_Enumeration_Literal
then
2853 Val
:= Enumeration_Pos
(Ent
);
2855 -- A user defined static constant
2858 pragma Assert
(Ekind
(Ent
) = E_Constant
);
2859 Val
:= Expr_Value
(Constant_Value
(Ent
));
2862 -- An integer literal that was either in the source or created
2863 -- as a result of static evaluation.
2865 elsif Kind
= N_Integer_Literal
then
2868 -- A real literal for a fixed-point type. This must be the fixed-point
2869 -- case, either the literal is of a fixed-point type, or it is a bound
2870 -- of a fixed-point type, with type universal real. In either case we
2871 -- obtain the desired value from Corresponding_Integer_Value.
2873 elsif Kind
= N_Real_Literal
then
2875 pragma Assert
(Is_Fixed_Point_Type
(Underlying_Type
(Etype
(N
))));
2876 Val
:= Corresponding_Integer_Value
(N
);
2878 -- Peculiar VMS case, if we have xxx'Null_Parameter, return zero
2880 elsif Kind
= N_Attribute_Reference
2881 and then Attribute_Name
(N
) = Name_Null_Parameter
2885 -- Otherwise must be character literal
2888 pragma Assert
(Kind
= N_Character_Literal
);
2891 -- Since Character literals of type Standard.Character don't
2892 -- have any defining character literals built for them, they
2893 -- do not have their Entity set, so just use their Char
2894 -- code. Otherwise for user-defined character literals use
2895 -- their Pos value as usual.
2898 Val
:= Char_Literal_Value
(N
);
2900 Val
:= Enumeration_Pos
(Ent
);
2904 -- Come here with Val set to value to be returned, set cache
2915 function Expr_Value_E
(N
: Node_Id
) return Entity_Id
is
2916 Ent
: constant Entity_Id
:= Entity
(N
);
2919 if Ekind
(Ent
) = E_Enumeration_Literal
then
2922 pragma Assert
(Ekind
(Ent
) = E_Constant
);
2923 return Expr_Value_E
(Constant_Value
(Ent
));
2931 function Expr_Value_R
(N
: Node_Id
) return Ureal
is
2932 Kind
: constant Node_Kind
:= Nkind
(N
);
2937 if Kind
= N_Real_Literal
then
2940 elsif Kind
= N_Identifier
or else Kind
= N_Expanded_Name
then
2942 pragma Assert
(Ekind
(Ent
) = E_Constant
);
2943 return Expr_Value_R
(Constant_Value
(Ent
));
2945 elsif Kind
= N_Integer_Literal
then
2946 return UR_From_Uint
(Expr_Value
(N
));
2948 -- Strange case of VAX literals, which are at this stage transformed
2949 -- into Vax_Type!x_To_y(IEEE_Literal). See Expand_N_Real_Literal in
2950 -- Exp_Vfpt for further details.
2952 elsif Vax_Float
(Etype
(N
))
2953 and then Nkind
(N
) = N_Unchecked_Type_Conversion
2955 Expr
:= Expression
(N
);
2957 if Nkind
(Expr
) = N_Function_Call
2958 and then Present
(Parameter_Associations
(Expr
))
2960 Expr
:= First
(Parameter_Associations
(Expr
));
2962 if Nkind
(Expr
) = N_Real_Literal
then
2963 return Realval
(Expr
);
2967 -- Peculiar VMS case, if we have xxx'Null_Parameter, return 0.0
2969 elsif Kind
= N_Attribute_Reference
2970 and then Attribute_Name
(N
) = Name_Null_Parameter
2975 -- If we fall through, we have a node that cannot be interepreted
2976 -- as a compile time constant. That is definitely an error.
2978 raise Program_Error
;
2985 function Expr_Value_S
(N
: Node_Id
) return Node_Id
is
2987 if Nkind
(N
) = N_String_Literal
then
2990 pragma Assert
(Ekind
(Entity
(N
)) = E_Constant
);
2991 return Expr_Value_S
(Constant_Value
(Entity
(N
)));
2995 --------------------------
2996 -- Flag_Non_Static_Expr --
2997 --------------------------
2999 procedure Flag_Non_Static_Expr
(Msg
: String; Expr
: Node_Id
) is
3001 if Error_Posted
(Expr
) and then not All_Errors_Mode
then
3004 Error_Msg_F
(Msg
, Expr
);
3005 Why_Not_Static
(Expr
);
3007 end Flag_Non_Static_Expr
;
3013 procedure Fold_Str
(N
: Node_Id
; Val
: String_Id
; Static
: Boolean) is
3014 Loc
: constant Source_Ptr
:= Sloc
(N
);
3015 Typ
: constant Entity_Id
:= Etype
(N
);
3018 Rewrite
(N
, Make_String_Literal
(Loc
, Strval
=> Val
));
3020 -- We now have the literal with the right value, both the actual type
3021 -- and the expected type of this literal are taken from the expression
3022 -- that was evaluated.
3025 Set_Is_Static_Expression
(N
, Static
);
3034 procedure Fold_Uint
(N
: Node_Id
; Val
: Uint
; Static
: Boolean) is
3035 Loc
: constant Source_Ptr
:= Sloc
(N
);
3036 Typ
: Entity_Id
:= Etype
(N
);
3040 -- If we are folding a named number, retain the entity in the
3041 -- literal, for ASIS use.
3043 if Is_Entity_Name
(N
)
3044 and then Ekind
(Entity
(N
)) = E_Named_Integer
3051 if Is_Private_Type
(Typ
) then
3052 Typ
:= Full_View
(Typ
);
3055 -- For a result of type integer, subsitute an N_Integer_Literal node
3056 -- for the result of the compile time evaluation of the expression.
3058 if Is_Integer_Type
(Typ
) then
3059 Rewrite
(N
, Make_Integer_Literal
(Loc
, Val
));
3060 Set_Original_Entity
(N
, Ent
);
3062 -- Otherwise we have an enumeration type, and we substitute either
3063 -- an N_Identifier or N_Character_Literal to represent the enumeration
3064 -- literal corresponding to the given value, which must always be in
3065 -- range, because appropriate tests have already been made for this.
3067 else pragma Assert
(Is_Enumeration_Type
(Typ
));
3068 Rewrite
(N
, Get_Enum_Lit_From_Pos
(Etype
(N
), Val
, Loc
));
3071 -- We now have the literal with the right value, both the actual type
3072 -- and the expected type of this literal are taken from the expression
3073 -- that was evaluated.
3076 Set_Is_Static_Expression
(N
, Static
);
3085 procedure Fold_Ureal
(N
: Node_Id
; Val
: Ureal
; Static
: Boolean) is
3086 Loc
: constant Source_Ptr
:= Sloc
(N
);
3087 Typ
: constant Entity_Id
:= Etype
(N
);
3091 -- If we are folding a named number, retain the entity in the
3092 -- literal, for ASIS use.
3094 if Is_Entity_Name
(N
)
3095 and then Ekind
(Entity
(N
)) = E_Named_Real
3102 Rewrite
(N
, Make_Real_Literal
(Loc
, Realval
=> Val
));
3103 Set_Original_Entity
(N
, Ent
);
3105 -- Both the actual and expected type comes from the original expression
3108 Set_Is_Static_Expression
(N
, Static
);
3117 function From_Bits
(B
: Bits
; T
: Entity_Id
) return Uint
is
3121 for J
in 0 .. B
'Last loop
3127 if Non_Binary_Modulus
(T
) then
3128 V
:= V
mod Modulus
(T
);
3134 --------------------
3135 -- Get_String_Val --
3136 --------------------
3138 function Get_String_Val
(N
: Node_Id
) return Node_Id
is
3140 if Nkind
(N
) = N_String_Literal
then
3143 elsif Nkind
(N
) = N_Character_Literal
then
3147 pragma Assert
(Is_Entity_Name
(N
));
3148 return Get_String_Val
(Constant_Value
(Entity
(N
)));
3156 procedure Initialize
is
3158 CV_Cache
:= (others => (Node_High_Bound
, Uint_0
));
3161 --------------------
3162 -- In_Subrange_Of --
3163 --------------------
3165 function In_Subrange_Of
3168 Fixed_Int
: Boolean := False) return Boolean
3177 if T1
= T2
or else Is_Subtype_Of
(T1
, T2
) then
3180 -- Never in range if both types are not scalar. Don't know if this can
3181 -- actually happen, but just in case.
3183 elsif not Is_Scalar_Type
(T1
) or else not Is_Scalar_Type
(T1
) then
3187 L1
:= Type_Low_Bound
(T1
);
3188 H1
:= Type_High_Bound
(T1
);
3190 L2
:= Type_Low_Bound
(T2
);
3191 H2
:= Type_High_Bound
(T2
);
3193 -- Check bounds to see if comparison possible at compile time
3195 if Compile_Time_Compare
(L1
, L2
) in Compare_GE
3197 Compile_Time_Compare
(H1
, H2
) in Compare_LE
3202 -- If bounds not comparable at compile time, then the bounds of T2
3203 -- must be compile time known or we cannot answer the query.
3205 if not Compile_Time_Known_Value
(L2
)
3206 or else not Compile_Time_Known_Value
(H2
)
3211 -- If the bounds of T1 are know at compile time then use these
3212 -- ones, otherwise use the bounds of the base type (which are of
3213 -- course always static).
3215 if not Compile_Time_Known_Value
(L1
) then
3216 L1
:= Type_Low_Bound
(Base_Type
(T1
));
3219 if not Compile_Time_Known_Value
(H1
) then
3220 H1
:= Type_High_Bound
(Base_Type
(T1
));
3223 -- Fixed point types should be considered as such only if
3224 -- flag Fixed_Int is set to False.
3226 if Is_Floating_Point_Type
(T1
) or else Is_Floating_Point_Type
(T2
)
3227 or else (Is_Fixed_Point_Type
(T1
) and then not Fixed_Int
)
3228 or else (Is_Fixed_Point_Type
(T2
) and then not Fixed_Int
)
3231 Expr_Value_R
(L2
) <= Expr_Value_R
(L1
)
3233 Expr_Value_R
(H2
) >= Expr_Value_R
(H1
);
3237 Expr_Value
(L2
) <= Expr_Value
(L1
)
3239 Expr_Value
(H2
) >= Expr_Value
(H1
);
3244 -- If any exception occurs, it means that we have some bug in the compiler
3245 -- possibly triggered by a previous error, or by some unforseen peculiar
3246 -- occurrence. However, this is only an optimization attempt, so there is
3247 -- really no point in crashing the compiler. Instead we just decide, too
3248 -- bad, we can't figure out the answer in this case after all.
3253 -- Debug flag K disables this behavior (useful for debugging)
3255 if Debug_Flag_K
then
3266 function Is_In_Range
3269 Fixed_Int
: Boolean := False;
3270 Int_Real
: Boolean := False) return Boolean
3276 -- Universal types have no range limits, so always in range
3278 if Typ
= Universal_Integer
or else Typ
= Universal_Real
then
3281 -- Never in range if not scalar type. Don't know if this can
3282 -- actually happen, but our spec allows it, so we must check!
3284 elsif not Is_Scalar_Type
(Typ
) then
3287 -- Never in range unless we have a compile time known value
3289 elsif not Compile_Time_Known_Value
(N
) then
3294 Lo
: constant Node_Id
:= Type_Low_Bound
(Typ
);
3295 Hi
: constant Node_Id
:= Type_High_Bound
(Typ
);
3296 LB_Known
: constant Boolean := Compile_Time_Known_Value
(Lo
);
3297 UB_Known
: constant Boolean := Compile_Time_Known_Value
(Hi
);
3300 -- Fixed point types should be considered as such only in
3301 -- flag Fixed_Int is set to False.
3303 if Is_Floating_Point_Type
(Typ
)
3304 or else (Is_Fixed_Point_Type
(Typ
) and then not Fixed_Int
)
3307 Valr
:= Expr_Value_R
(N
);
3309 if LB_Known
and then Valr
>= Expr_Value_R
(Lo
)
3310 and then UB_Known
and then Valr
<= Expr_Value_R
(Hi
)
3318 Val
:= Expr_Value
(N
);
3320 if LB_Known
and then Val
>= Expr_Value
(Lo
)
3321 and then UB_Known
and then Val
<= Expr_Value
(Hi
)
3336 function Is_Null_Range
(Lo
: Node_Id
; Hi
: Node_Id
) return Boolean is
3337 Typ
: constant Entity_Id
:= Etype
(Lo
);
3340 if not Compile_Time_Known_Value
(Lo
)
3341 or else not Compile_Time_Known_Value
(Hi
)
3346 if Is_Discrete_Type
(Typ
) then
3347 return Expr_Value
(Lo
) > Expr_Value
(Hi
);
3350 pragma Assert
(Is_Real_Type
(Typ
));
3351 return Expr_Value_R
(Lo
) > Expr_Value_R
(Hi
);
3355 -----------------------------
3356 -- Is_OK_Static_Expression --
3357 -----------------------------
3359 function Is_OK_Static_Expression
(N
: Node_Id
) return Boolean is
3361 return Is_Static_Expression
(N
)
3362 and then not Raises_Constraint_Error
(N
);
3363 end Is_OK_Static_Expression
;
3365 ------------------------
3366 -- Is_OK_Static_Range --
3367 ------------------------
3369 -- A static range is a range whose bounds are static expressions, or a
3370 -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)).
3371 -- We have already converted range attribute references, so we get the
3372 -- "or" part of this rule without needing a special test.
3374 function Is_OK_Static_Range
(N
: Node_Id
) return Boolean is
3376 return Is_OK_Static_Expression
(Low_Bound
(N
))
3377 and then Is_OK_Static_Expression
(High_Bound
(N
));
3378 end Is_OK_Static_Range
;
3380 --------------------------
3381 -- Is_OK_Static_Subtype --
3382 --------------------------
3384 -- Determines if Typ is a static subtype as defined in (RM 4.9(26))
3385 -- where neither bound raises constraint error when evaluated.
3387 function Is_OK_Static_Subtype
(Typ
: Entity_Id
) return Boolean is
3388 Base_T
: constant Entity_Id
:= Base_Type
(Typ
);
3389 Anc_Subt
: Entity_Id
;
3392 -- First a quick check on the non static subtype flag. As described
3393 -- in further detail in Einfo, this flag is not decisive in all cases,
3394 -- but if it is set, then the subtype is definitely non-static.
3396 if Is_Non_Static_Subtype
(Typ
) then
3400 Anc_Subt
:= Ancestor_Subtype
(Typ
);
3402 if Anc_Subt
= Empty
then
3406 if Is_Generic_Type
(Root_Type
(Base_T
))
3407 or else Is_Generic_Actual_Type
(Base_T
)
3413 elsif Is_String_Type
(Typ
) then
3415 Ekind
(Typ
) = E_String_Literal_Subtype
3417 (Is_OK_Static_Subtype
(Component_Type
(Typ
))
3418 and then Is_OK_Static_Subtype
(Etype
(First_Index
(Typ
))));
3422 elsif Is_Scalar_Type
(Typ
) then
3423 if Base_T
= Typ
then
3427 -- Scalar_Range (Typ) might be an N_Subtype_Indication, so
3428 -- use Get_Type_Low,High_Bound.
3430 return Is_OK_Static_Subtype
(Anc_Subt
)
3431 and then Is_OK_Static_Expression
(Type_Low_Bound
(Typ
))
3432 and then Is_OK_Static_Expression
(Type_High_Bound
(Typ
));
3435 -- Types other than string and scalar types are never static
3440 end Is_OK_Static_Subtype
;
3442 ---------------------
3443 -- Is_Out_Of_Range --
3444 ---------------------
3446 function Is_Out_Of_Range
3449 Fixed_Int
: Boolean := False;
3450 Int_Real
: Boolean := False) return Boolean
3456 -- Universal types have no range limits, so always in range
3458 if Typ
= Universal_Integer
or else Typ
= Universal_Real
then
3461 -- Never out of range if not scalar type. Don't know if this can
3462 -- actually happen, but our spec allows it, so we must check!
3464 elsif not Is_Scalar_Type
(Typ
) then
3467 -- Never out of range if this is a generic type, since the bounds
3468 -- of generic types are junk. Note that if we only checked for
3469 -- static expressions (instead of compile time known values) below,
3470 -- we would not need this check, because values of a generic type
3471 -- can never be static, but they can be known at compile time.
3473 elsif Is_Generic_Type
(Typ
) then
3476 -- Never out of range unless we have a compile time known value
3478 elsif not Compile_Time_Known_Value
(N
) then
3483 Lo
: constant Node_Id
:= Type_Low_Bound
(Typ
);
3484 Hi
: constant Node_Id
:= Type_High_Bound
(Typ
);
3485 LB_Known
: constant Boolean := Compile_Time_Known_Value
(Lo
);
3486 UB_Known
: constant Boolean := Compile_Time_Known_Value
(Hi
);
3489 -- Real types (note that fixed-point types are not treated
3490 -- as being of a real type if the flag Fixed_Int is set,
3491 -- since in that case they are regarded as integer types).
3493 if Is_Floating_Point_Type
(Typ
)
3494 or else (Is_Fixed_Point_Type
(Typ
) and then not Fixed_Int
)
3497 Valr
:= Expr_Value_R
(N
);
3499 if LB_Known
and then Valr
< Expr_Value_R
(Lo
) then
3502 elsif UB_Known
and then Expr_Value_R
(Hi
) < Valr
then
3510 Val
:= Expr_Value
(N
);
3512 if LB_Known
and then Val
< Expr_Value
(Lo
) then
3515 elsif UB_Known
and then Expr_Value
(Hi
) < Val
then
3524 end Is_Out_Of_Range
;
3526 ---------------------
3527 -- Is_Static_Range --
3528 ---------------------
3530 -- A static range is a range whose bounds are static expressions, or a
3531 -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)).
3532 -- We have already converted range attribute references, so we get the
3533 -- "or" part of this rule without needing a special test.
3535 function Is_Static_Range
(N
: Node_Id
) return Boolean is
3537 return Is_Static_Expression
(Low_Bound
(N
))
3538 and then Is_Static_Expression
(High_Bound
(N
));
3539 end Is_Static_Range
;
3541 -----------------------
3542 -- Is_Static_Subtype --
3543 -----------------------
3545 -- Determines if Typ is a static subtype as defined in (RM 4.9(26))
3547 function Is_Static_Subtype
(Typ
: Entity_Id
) return Boolean is
3548 Base_T
: constant Entity_Id
:= Base_Type
(Typ
);
3549 Anc_Subt
: Entity_Id
;
3552 -- First a quick check on the non static subtype flag. As described
3553 -- in further detail in Einfo, this flag is not decisive in all cases,
3554 -- but if it is set, then the subtype is definitely non-static.
3556 if Is_Non_Static_Subtype
(Typ
) then
3560 Anc_Subt
:= Ancestor_Subtype
(Typ
);
3562 if Anc_Subt
= Empty
then
3566 if Is_Generic_Type
(Root_Type
(Base_T
))
3567 or else Is_Generic_Actual_Type
(Base_T
)
3573 elsif Is_String_Type
(Typ
) then
3575 Ekind
(Typ
) = E_String_Literal_Subtype
3577 (Is_Static_Subtype
(Component_Type
(Typ
))
3578 and then Is_Static_Subtype
(Etype
(First_Index
(Typ
))));
3582 elsif Is_Scalar_Type
(Typ
) then
3583 if Base_T
= Typ
then
3587 return Is_Static_Subtype
(Anc_Subt
)
3588 and then Is_Static_Expression
(Type_Low_Bound
(Typ
))
3589 and then Is_Static_Expression
(Type_High_Bound
(Typ
));
3592 -- Types other than string and scalar types are never static
3597 end Is_Static_Subtype
;
3599 --------------------
3600 -- Not_Null_Range --
3601 --------------------
3603 function Not_Null_Range
(Lo
: Node_Id
; Hi
: Node_Id
) return Boolean is
3604 Typ
: constant Entity_Id
:= Etype
(Lo
);
3607 if not Compile_Time_Known_Value
(Lo
)
3608 or else not Compile_Time_Known_Value
(Hi
)
3613 if Is_Discrete_Type
(Typ
) then
3614 return Expr_Value
(Lo
) <= Expr_Value
(Hi
);
3617 pragma Assert
(Is_Real_Type
(Typ
));
3619 return Expr_Value_R
(Lo
) <= Expr_Value_R
(Hi
);
3627 function OK_Bits
(N
: Node_Id
; Bits
: Uint
) return Boolean is
3629 -- We allow a maximum of 500,000 bits which seems a reasonable limit
3631 if Bits
< 500_000
then
3635 Error_Msg_N
("static value too large, capacity exceeded", N
);
3644 procedure Out_Of_Range
(N
: Node_Id
) is
3646 -- If we have the static expression case, then this is an illegality
3647 -- in Ada 95 mode, except that in an instance, we never generate an
3648 -- error (if the error is legitimate, it was already diagnosed in
3649 -- the template). The expression to compute the length of a packed
3650 -- array is attached to the array type itself, and deserves a separate
3653 if Is_Static_Expression
(N
)
3654 and then not In_Instance
3655 and then not In_Inlined_Body
3656 and then Ada_Version
>= Ada_95
3658 if Nkind
(Parent
(N
)) = N_Defining_Identifier
3659 and then Is_Array_Type
(Parent
(N
))
3660 and then Present
(Packed_Array_Type
(Parent
(N
)))
3661 and then Present
(First_Rep_Item
(Parent
(N
)))
3664 ("length of packed array must not exceed Integer''Last",
3665 First_Rep_Item
(Parent
(N
)));
3666 Rewrite
(N
, Make_Integer_Literal
(Sloc
(N
), Uint_1
));
3669 Apply_Compile_Time_Constraint_Error
3670 (N
, "value not in range of}", CE_Range_Check_Failed
);
3673 -- Here we generate a warning for the Ada 83 case, or when we are
3674 -- in an instance, or when we have a non-static expression case.
3677 Apply_Compile_Time_Constraint_Error
3678 (N
, "value not in range of}?", CE_Range_Check_Failed
);
3682 -------------------------
3683 -- Rewrite_In_Raise_CE --
3684 -------------------------
3686 procedure Rewrite_In_Raise_CE
(N
: Node_Id
; Exp
: Node_Id
) is
3687 Typ
: constant Entity_Id
:= Etype
(N
);
3690 -- If we want to raise CE in the condition of a raise_CE node
3691 -- we may as well get rid of the condition
3693 if Present
(Parent
(N
))
3694 and then Nkind
(Parent
(N
)) = N_Raise_Constraint_Error
3696 Set_Condition
(Parent
(N
), Empty
);
3698 -- If the expression raising CE is a N_Raise_CE node, we can use
3699 -- that one. We just preserve the type of the context
3701 elsif Nkind
(Exp
) = N_Raise_Constraint_Error
then
3705 -- We have to build an explicit raise_ce node
3709 Make_Raise_Constraint_Error
(Sloc
(Exp
),
3710 Reason
=> CE_Range_Check_Failed
));
3711 Set_Raises_Constraint_Error
(N
);
3714 end Rewrite_In_Raise_CE
;
3716 ---------------------
3717 -- String_Type_Len --
3718 ---------------------
3720 function String_Type_Len
(Stype
: Entity_Id
) return Uint
is
3721 NT
: constant Entity_Id
:= Etype
(First_Index
(Stype
));
3725 if Is_OK_Static_Subtype
(NT
) then
3728 T
:= Base_Type
(NT
);
3731 return Expr_Value
(Type_High_Bound
(T
)) -
3732 Expr_Value
(Type_Low_Bound
(T
)) + 1;
3733 end String_Type_Len
;
3735 ------------------------------------
3736 -- Subtypes_Statically_Compatible --
3737 ------------------------------------
3739 function Subtypes_Statically_Compatible
3741 T2
: Entity_Id
) return Boolean
3744 if Is_Scalar_Type
(T1
) then
3746 -- Definitely compatible if we match
3748 if Subtypes_Statically_Match
(T1
, T2
) then
3751 -- If either subtype is nonstatic then they're not compatible
3753 elsif not Is_Static_Subtype
(T1
)
3754 or else not Is_Static_Subtype
(T2
)
3758 -- If either type has constraint error bounds, then consider that
3759 -- they match to avoid junk cascaded errors here.
3761 elsif not Is_OK_Static_Subtype
(T1
)
3762 or else not Is_OK_Static_Subtype
(T2
)
3766 -- Base types must match, but we don't check that (should
3767 -- we???) but we do at least check that both types are
3768 -- real, or both types are not real.
3770 elsif Is_Real_Type
(T1
) /= Is_Real_Type
(T2
) then
3773 -- Here we check the bounds
3777 LB1
: constant Node_Id
:= Type_Low_Bound
(T1
);
3778 HB1
: constant Node_Id
:= Type_High_Bound
(T1
);
3779 LB2
: constant Node_Id
:= Type_Low_Bound
(T2
);
3780 HB2
: constant Node_Id
:= Type_High_Bound
(T2
);
3783 if Is_Real_Type
(T1
) then
3785 (Expr_Value_R
(LB1
) > Expr_Value_R
(HB1
))
3787 (Expr_Value_R
(LB2
) <= Expr_Value_R
(LB1
)
3789 Expr_Value_R
(HB1
) <= Expr_Value_R
(HB2
));
3793 (Expr_Value
(LB1
) > Expr_Value
(HB1
))
3795 (Expr_Value
(LB2
) <= Expr_Value
(LB1
)
3797 Expr_Value
(HB1
) <= Expr_Value
(HB2
));
3802 elsif Is_Access_Type
(T1
) then
3803 return not Is_Constrained
(T2
)
3804 or else Subtypes_Statically_Match
3805 (Designated_Type
(T1
), Designated_Type
(T2
));
3808 return (Is_Composite_Type
(T1
) and then not Is_Constrained
(T2
))
3809 or else Subtypes_Statically_Match
(T1
, T2
);
3811 end Subtypes_Statically_Compatible
;
3813 -------------------------------
3814 -- Subtypes_Statically_Match --
3815 -------------------------------
3817 -- Subtypes statically match if they have statically matching constraints
3818 -- (RM 4.9.1(2)). Constraints statically match if there are none, or if
3819 -- they are the same identical constraint, or if they are static and the
3820 -- values match (RM 4.9.1(1)).
3822 function Subtypes_Statically_Match
(T1
, T2
: Entity_Id
) return Boolean is
3824 -- A type always statically matches itself
3831 elsif Is_Scalar_Type
(T1
) then
3833 -- Base types must be the same
3835 if Base_Type
(T1
) /= Base_Type
(T2
) then
3839 -- A constrained numeric subtype never matches an unconstrained
3840 -- subtype, i.e. both types must be constrained or unconstrained.
3842 -- To understand the requirement for this test, see RM 4.9.1(1).
3843 -- As is made clear in RM 3.5.4(11), type Integer, for example
3844 -- is a constrained subtype with constraint bounds matching the
3845 -- bounds of its corresponding uncontrained base type. In this
3846 -- situation, Integer and Integer'Base do not statically match,
3847 -- even though they have the same bounds.
3849 -- We only apply this test to types in Standard and types that
3850 -- appear in user programs. That way, we do not have to be
3851 -- too careful about setting Is_Constrained right for itypes.
3853 if Is_Numeric_Type
(T1
)
3854 and then (Is_Constrained
(T1
) /= Is_Constrained
(T2
))
3855 and then (Scope
(T1
) = Standard_Standard
3856 or else Comes_From_Source
(T1
))
3857 and then (Scope
(T2
) = Standard_Standard
3858 or else Comes_From_Source
(T2
))
3862 -- A generic scalar type does not statically match its base
3863 -- type (AI-311). In this case we make sure that the formals,
3864 -- which are first subtypes of their bases, are constrained.
3866 elsif Is_Generic_Type
(T1
)
3867 and then Is_Generic_Type
(T2
)
3868 and then (Is_Constrained
(T1
) /= Is_Constrained
(T2
))
3873 -- If there was an error in either range, then just assume
3874 -- the types statically match to avoid further junk errors
3876 if Error_Posted
(Scalar_Range
(T1
))
3878 Error_Posted
(Scalar_Range
(T2
))
3883 -- Otherwise both types have bound that can be compared
3886 LB1
: constant Node_Id
:= Type_Low_Bound
(T1
);
3887 HB1
: constant Node_Id
:= Type_High_Bound
(T1
);
3888 LB2
: constant Node_Id
:= Type_Low_Bound
(T2
);
3889 HB2
: constant Node_Id
:= Type_High_Bound
(T2
);
3892 -- If the bounds are the same tree node, then match
3894 if LB1
= LB2
and then HB1
= HB2
then
3897 -- Otherwise bounds must be static and identical value
3900 if not Is_Static_Subtype
(T1
)
3901 or else not Is_Static_Subtype
(T2
)
3905 -- If either type has constraint error bounds, then say
3906 -- that they match to avoid junk cascaded errors here.
3908 elsif not Is_OK_Static_Subtype
(T1
)
3909 or else not Is_OK_Static_Subtype
(T2
)
3913 elsif Is_Real_Type
(T1
) then
3915 (Expr_Value_R
(LB1
) = Expr_Value_R
(LB2
))
3917 (Expr_Value_R
(HB1
) = Expr_Value_R
(HB2
));
3921 Expr_Value
(LB1
) = Expr_Value
(LB2
)
3923 Expr_Value
(HB1
) = Expr_Value
(HB2
);
3928 -- Type with discriminants
3930 elsif Has_Discriminants
(T1
) or else Has_Discriminants
(T2
) then
3932 -- Because of view exchanges in multiple instantiations, conformance
3933 -- checking might try to match a partial view of a type with no
3934 -- discriminants with a full view that has defaulted discriminants.
3935 -- In such a case, use the discriminant constraint of the full view,
3936 -- which must exist because we know that the two subtypes have the
3939 if Has_Discriminants
(T1
) /= Has_Discriminants
(T2
) then
3941 if Is_Private_Type
(T2
)
3942 and then Present
(Full_View
(T2
))
3943 and then Has_Discriminants
(Full_View
(T2
))
3945 return Subtypes_Statically_Match
(T1
, Full_View
(T2
));
3947 elsif Is_Private_Type
(T1
)
3948 and then Present
(Full_View
(T1
))
3949 and then Has_Discriminants
(Full_View
(T1
))
3951 return Subtypes_Statically_Match
(Full_View
(T1
), T2
);
3962 DL1
: constant Elist_Id
:= Discriminant_Constraint
(T1
);
3963 DL2
: constant Elist_Id
:= Discriminant_Constraint
(T2
);
3965 DA1
: Elmt_Id
:= First_Elmt
(DL1
);
3966 DA2
: Elmt_Id
:= First_Elmt
(DL2
);
3972 elsif Is_Constrained
(T1
) /= Is_Constrained
(T2
) then
3976 while Present
(DA1
) loop
3978 Expr1
: constant Node_Id
:= Node
(DA1
);
3979 Expr2
: constant Node_Id
:= Node
(DA2
);
3982 if not Is_Static_Expression
(Expr1
)
3983 or else not Is_Static_Expression
(Expr2
)
3987 -- If either expression raised a constraint error,
3988 -- consider the expressions as matching, since this
3989 -- helps to prevent cascading errors.
3991 elsif Raises_Constraint_Error
(Expr1
)
3992 or else Raises_Constraint_Error
(Expr2
)
3996 elsif Expr_Value
(Expr1
) /= Expr_Value
(Expr2
) then
4008 -- A definite type does not match an indefinite or classwide type
4009 -- However, a generic type with unknown discriminants may be
4010 -- instantiated with a type with no discriminants, and conformance
4011 -- checking on an inherited operation may compare the actual with
4012 -- the subtype that renames it in the instance.
4015 Has_Unknown_Discriminants
(T1
) /= Has_Unknown_Discriminants
(T2
)
4017 if Is_Generic_Actual_Type
(T1
)
4018 and then Etype
(T1
) = T2
4027 elsif Is_Array_Type
(T1
) then
4029 -- If either subtype is unconstrained then both must be,
4030 -- and if both are unconstrained then no further checking
4033 if not Is_Constrained
(T1
) or else not Is_Constrained
(T2
) then
4034 return not (Is_Constrained
(T1
) or else Is_Constrained
(T2
));
4037 -- Both subtypes are constrained, so check that the index
4038 -- subtypes statically match.
4041 Index1
: Node_Id
:= First_Index
(T1
);
4042 Index2
: Node_Id
:= First_Index
(T2
);
4045 while Present
(Index1
) loop
4047 Subtypes_Statically_Match
(Etype
(Index1
), Etype
(Index2
))
4052 Next_Index
(Index1
);
4053 Next_Index
(Index2
);
4059 elsif Is_Access_Type
(T1
) then
4060 if Can_Never_Be_Null
(T1
) /= Can_Never_Be_Null
(T2
) then
4063 elsif Ekind
(T1
) = E_Access_Subprogram_Type
then
4066 (Designated_Type
(T1
),
4067 Designated_Type
(T1
));
4070 Subtypes_Statically_Match
4071 (Designated_Type
(T1
),
4072 Designated_Type
(T2
))
4073 and then Is_Access_Constant
(T1
) = Is_Access_Constant
(T2
);
4076 -- All other types definitely match
4081 end Subtypes_Statically_Match
;
4087 function Test
(Cond
: Boolean) return Uint
is
4096 ---------------------------------
4097 -- Test_Expression_Is_Foldable --
4098 ---------------------------------
4102 procedure Test_Expression_Is_Foldable
4112 if Debug_Flag_Dot_F
and then In_Extended_Main_Source_Unit
(N
) then
4116 -- If operand is Any_Type, just propagate to result and do not
4117 -- try to fold, this prevents cascaded errors.
4119 if Etype
(Op1
) = Any_Type
then
4120 Set_Etype
(N
, Any_Type
);
4123 -- If operand raises constraint error, then replace node N with the
4124 -- raise constraint error node, and we are obviously not foldable.
4125 -- Note that this replacement inherits the Is_Static_Expression flag
4126 -- from the operand.
4128 elsif Raises_Constraint_Error
(Op1
) then
4129 Rewrite_In_Raise_CE
(N
, Op1
);
4132 -- If the operand is not static, then the result is not static, and
4133 -- all we have to do is to check the operand since it is now known
4134 -- to appear in a non-static context.
4136 elsif not Is_Static_Expression
(Op1
) then
4137 Check_Non_Static_Context
(Op1
);
4138 Fold
:= Compile_Time_Known_Value
(Op1
);
4141 -- An expression of a formal modular type is not foldable because
4142 -- the modulus is unknown.
4144 elsif Is_Modular_Integer_Type
(Etype
(Op1
))
4145 and then Is_Generic_Type
(Etype
(Op1
))
4147 Check_Non_Static_Context
(Op1
);
4150 -- Here we have the case of an operand whose type is OK, which is
4151 -- static, and which does not raise constraint error, we can fold.
4154 Set_Is_Static_Expression
(N
);
4158 end Test_Expression_Is_Foldable
;
4162 procedure Test_Expression_Is_Foldable
4169 Rstat
: constant Boolean := Is_Static_Expression
(Op1
)
4170 and then Is_Static_Expression
(Op2
);
4176 if Debug_Flag_Dot_F
and then In_Extended_Main_Source_Unit
(N
) then
4180 -- If either operand is Any_Type, just propagate to result and
4181 -- do not try to fold, this prevents cascaded errors.
4183 if Etype
(Op1
) = Any_Type
or else Etype
(Op2
) = Any_Type
then
4184 Set_Etype
(N
, Any_Type
);
4187 -- If left operand raises constraint error, then replace node N with
4188 -- the raise constraint error node, and we are obviously not foldable.
4189 -- Is_Static_Expression is set from the two operands in the normal way,
4190 -- and we check the right operand if it is in a non-static context.
4192 elsif Raises_Constraint_Error
(Op1
) then
4194 Check_Non_Static_Context
(Op2
);
4197 Rewrite_In_Raise_CE
(N
, Op1
);
4198 Set_Is_Static_Expression
(N
, Rstat
);
4201 -- Similar processing for the case of the right operand. Note that
4202 -- we don't use this routine for the short-circuit case, so we do
4203 -- not have to worry about that special case here.
4205 elsif Raises_Constraint_Error
(Op2
) then
4207 Check_Non_Static_Context
(Op1
);
4210 Rewrite_In_Raise_CE
(N
, Op2
);
4211 Set_Is_Static_Expression
(N
, Rstat
);
4214 -- Exclude expressions of a generic modular type, as above
4216 elsif Is_Modular_Integer_Type
(Etype
(Op1
))
4217 and then Is_Generic_Type
(Etype
(Op1
))
4219 Check_Non_Static_Context
(Op1
);
4222 -- If result is not static, then check non-static contexts on operands
4223 -- since one of them may be static and the other one may not be static
4225 elsif not Rstat
then
4226 Check_Non_Static_Context
(Op1
);
4227 Check_Non_Static_Context
(Op2
);
4228 Fold
:= Compile_Time_Known_Value
(Op1
)
4229 and then Compile_Time_Known_Value
(Op2
);
4232 -- Else result is static and foldable. Both operands are static,
4233 -- and neither raises constraint error, so we can definitely fold.
4236 Set_Is_Static_Expression
(N
);
4241 end Test_Expression_Is_Foldable
;
4247 procedure To_Bits
(U
: Uint
; B
: out Bits
) is
4249 for J
in 0 .. B
'Last loop
4250 B
(J
) := (U
/ (2 ** J
)) mod 2 /= 0;
4254 --------------------
4255 -- Why_Not_Static --
4256 --------------------
4258 procedure Why_Not_Static
(Expr
: Node_Id
) is
4259 N
: constant Node_Id
:= Original_Node
(Expr
);
4263 procedure Why_Not_Static_List
(L
: List_Id
);
4264 -- A version that can be called on a list of expressions. Finds
4265 -- all non-static violations in any element of the list.
4267 -------------------------
4268 -- Why_Not_Static_List --
4269 -------------------------
4271 procedure Why_Not_Static_List
(L
: List_Id
) is
4275 if Is_Non_Empty_List
(L
) then
4277 while Present
(N
) loop
4282 end Why_Not_Static_List
;
4284 -- Start of processing for Why_Not_Static
4287 -- If in ACATS mode (debug flag 2), then suppress all these
4288 -- messages, this avoids massive updates to the ACATS base line.
4290 if Debug_Flag_2
then
4294 -- Ignore call on error or empty node
4296 if No
(Expr
) or else Nkind
(Expr
) = N_Error
then
4300 -- Preprocessing for sub expressions
4302 if Nkind
(Expr
) in N_Subexpr
then
4304 -- Nothing to do if expression is static
4306 if Is_OK_Static_Expression
(Expr
) then
4310 -- Test for constraint error raised
4312 if Raises_Constraint_Error
(Expr
) then
4314 ("expression raises exception, cannot be static " &
4315 "('R'M 4.9(34))!", N
);
4319 -- If no type, then something is pretty wrong, so ignore
4321 Typ
:= Etype
(Expr
);
4327 -- Type must be scalar or string type
4329 if not Is_Scalar_Type
(Typ
)
4330 and then not Is_String_Type
(Typ
)
4333 ("static expression must have scalar or string type " &
4334 "('R'M 4.9(2))!", N
);
4339 -- If we got through those checks, test particular node kind
4342 when N_Expanded_Name | N_Identifier | N_Operator_Symbol
=>
4345 if Is_Named_Number
(E
) then
4348 elsif Ekind
(E
) = E_Constant
then
4349 if not Is_Static_Expression
(Constant_Value
(E
)) then
4351 ("& is not a static constant ('R'M 4.9(5))!", N
, E
);
4356 ("& is not static constant or named number " &
4357 "('R'M 4.9(5))!", N
, E
);
4360 when N_Binary_Op | N_And_Then | N_Or_Else | N_In | N_Not_In
=>
4361 if Nkind
(N
) in N_Op_Shift
then
4363 ("shift functions are never static ('R'M 4.9(6,18))!", N
);
4366 Why_Not_Static
(Left_Opnd
(N
));
4367 Why_Not_Static
(Right_Opnd
(N
));
4371 Why_Not_Static
(Right_Opnd
(N
));
4373 when N_Attribute_Reference
=>
4374 Why_Not_Static_List
(Expressions
(N
));
4376 E
:= Etype
(Prefix
(N
));
4378 if E
= Standard_Void_Type
then
4382 -- Special case non-scalar'Size since this is a common error
4384 if Attribute_Name
(N
) = Name_Size
then
4386 ("size attribute is only static for scalar type " &
4387 "('R'M 4.9(7,8))", N
);
4391 elsif Is_Array_Type
(E
) then
4392 if Attribute_Name
(N
) /= Name_First
4394 Attribute_Name
(N
) /= Name_Last
4396 Attribute_Name
(N
) /= Name_Length
4399 ("static array attribute must be Length, First, or Last " &
4400 "('R'M 4.9(8))!", N
);
4402 -- Since we know the expression is not-static (we already
4403 -- tested for this, must mean array is not static).
4407 ("prefix is non-static array ('R'M 4.9(8))!", Prefix
(N
));
4412 -- Special case generic types, since again this is a common
4413 -- source of confusion.
4415 elsif Is_Generic_Actual_Type
(E
)
4420 ("attribute of generic type is never static " &
4421 "('R'M 4.9(7,8))!", N
);
4423 elsif Is_Static_Subtype
(E
) then
4426 elsif Is_Scalar_Type
(E
) then
4428 ("prefix type for attribute is not static scalar subtype " &
4429 "('R'M 4.9(7))!", N
);
4433 ("static attribute must apply to array/scalar type " &
4434 "('R'M 4.9(7,8))!", N
);
4437 when N_String_Literal
=>
4439 ("subtype of string literal is non-static ('R'M 4.9(4))!", N
);
4441 when N_Explicit_Dereference
=>
4443 ("explicit dereference is never static ('R'M 4.9)!", N
);
4445 when N_Function_Call
=>
4446 Why_Not_Static_List
(Parameter_Associations
(N
));
4447 Error_Msg_N
("non-static function call ('R'M 4.9(6,18))!", N
);
4449 when N_Parameter_Association
=>
4450 Why_Not_Static
(Explicit_Actual_Parameter
(N
));
4452 when N_Indexed_Component
=>
4454 ("indexed component is never static ('R'M 4.9)!", N
);
4456 when N_Procedure_Call_Statement
=>
4458 ("procedure call is never static ('R'M 4.9)!", N
);
4460 when N_Qualified_Expression
=>
4461 Why_Not_Static
(Expression
(N
));
4463 when N_Aggregate | N_Extension_Aggregate
=>
4465 ("an aggregate is never static ('R'M 4.9)!", N
);
4468 Why_Not_Static
(Low_Bound
(N
));
4469 Why_Not_Static
(High_Bound
(N
));
4471 when N_Range_Constraint
=>
4472 Why_Not_Static
(Range_Expression
(N
));
4474 when N_Subtype_Indication
=>
4475 Why_Not_Static
(Constraint
(N
));
4477 when N_Selected_Component
=>
4479 ("selected component is never static ('R'M 4.9)!", N
);
4483 ("slice is never static ('R'M 4.9)!", N
);
4485 when N_Type_Conversion
=>
4486 Why_Not_Static
(Expression
(N
));
4488 if not Is_Scalar_Type
(Etype
(Prefix
(N
)))
4489 or else not Is_Static_Subtype
(Etype
(Prefix
(N
)))
4492 ("static conversion requires static scalar subtype result " &
4493 "('R'M 4.9(9))!", N
);
4496 when N_Unchecked_Type_Conversion
=>
4498 ("unchecked type conversion is never static ('R'M 4.9)!", N
);