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
;
35 with Nmake
; use Nmake
;
36 with Nlists
; use Nlists
;
39 with Sem_Cat
; use Sem_Cat
;
40 with Sem_Ch8
; use Sem_Ch8
;
41 with Sem_Res
; use Sem_Res
;
42 with Sem_Util
; use Sem_Util
;
43 with Sem_Type
; use Sem_Type
;
44 with Sem_Warn
; use Sem_Warn
;
45 with Sinfo
; use Sinfo
;
46 with Snames
; use Snames
;
47 with Stand
; use Stand
;
48 with Stringt
; use Stringt
;
49 with Tbuild
; use Tbuild
;
51 package body Sem_Eval
is
53 -----------------------------------------
54 -- Handling of Compile Time Evaluation --
55 -----------------------------------------
57 -- The compile time evaluation of expressions is distributed over several
58 -- Eval_xxx procedures. These procedures are called immediatedly after
59 -- a subexpression is resolved and is therefore accomplished in a bottom
60 -- up fashion. The flags are synthesized using the following approach.
62 -- Is_Static_Expression is determined by following the detailed rules
63 -- in RM 4.9(4-14). This involves testing the Is_Static_Expression
64 -- flag of the operands in many cases.
66 -- Raises_Constraint_Error is set if any of the operands have the flag
67 -- set or if an attempt to compute the value of the current expression
68 -- results in detection of a runtime constraint error.
70 -- As described in the spec, the requirement is that Is_Static_Expression
71 -- be accurately set, and in addition for nodes for which this flag is set,
72 -- Raises_Constraint_Error must also be set. Furthermore a node which has
73 -- Is_Static_Expression set, and Raises_Constraint_Error clear, then the
74 -- requirement is that the expression value must be precomputed, and the
75 -- node is either a literal, or the name of a constant entity whose value
76 -- is a static expression.
78 -- The general approach is as follows. First compute Is_Static_Expression.
79 -- If the node is not static, then the flag is left off in the node and
80 -- we are all done. Otherwise for a static node, we test if any of the
81 -- operands will raise constraint error, and if so, propagate the flag
82 -- Raises_Constraint_Error to the result node and we are done (since the
83 -- error was already posted at a lower level).
85 -- For the case of a static node whose operands do not raise constraint
86 -- error, we attempt to evaluate the node. If this evaluation succeeds,
87 -- then the node is replaced by the result of this computation. If the
88 -- evaluation raises constraint error, then we rewrite the node with
89 -- Apply_Compile_Time_Constraint_Error to raise the exception and also
90 -- to post appropriate error messages.
96 type Bits
is array (Nat
range <>) of Boolean;
97 -- Used to convert unsigned (modular) values for folding logical ops
99 -- The following definitions are used to maintain a cache of nodes that
100 -- have compile time known values. The cache is maintained only for
101 -- discrete types (the most common case), and is populated by calls to
102 -- Compile_Time_Known_Value and Expr_Value, but only used by Expr_Value
103 -- since it is possible for the status to change (in particular it is
104 -- possible for a node to get replaced by a constraint error node).
106 CV_Bits
: constant := 5;
107 -- Number of low order bits of Node_Id value used to reference entries
108 -- in the cache table.
110 CV_Cache_Size
: constant Nat
:= 2 ** CV_Bits
;
111 -- Size of cache for compile time values
113 subtype CV_Range
is Nat
range 0 .. CV_Cache_Size
;
115 type CV_Entry
is record
120 type CV_Cache_Array
is array (CV_Range
) of CV_Entry
;
122 CV_Cache
: CV_Cache_Array
:= (others => (Node_High_Bound
, Uint_0
));
123 -- This is the actual cache, with entries consisting of node/value pairs,
124 -- and the impossible value Node_High_Bound used for unset entries.
126 -----------------------
127 -- Local Subprograms --
128 -----------------------
130 function From_Bits
(B
: Bits
; T
: Entity_Id
) return Uint
;
131 -- Converts a bit string of length B'Length to a Uint value to be used
132 -- for a target of type T, which is a modular type. This procedure
133 -- includes the necessary reduction by the modulus in the case of a
134 -- non-binary modulus (for a binary modulus, the bit string is the
135 -- right length any way so all is well).
137 function Get_String_Val
(N
: Node_Id
) return Node_Id
;
138 -- Given a tree node for a folded string or character value, returns
139 -- the corresponding string literal or character literal (one of the
140 -- two must be available, or the operand would not have been marked
141 -- as foldable in the earlier analysis of the operation).
143 function OK_Bits
(N
: Node_Id
; Bits
: Uint
) return Boolean;
144 -- Bits represents the number of bits in an integer value to be computed
145 -- (but the value has not been computed yet). If this value in Bits is
146 -- reasonable, a result of True is returned, with the implication that
147 -- the caller should go ahead and complete the calculation. If the value
148 -- in Bits is unreasonably large, then an error is posted on node N, and
149 -- False is returned (and the caller skips the proposed calculation).
151 procedure Out_Of_Range
(N
: Node_Id
);
152 -- This procedure is called if it is determined that node N, which
153 -- appears in a non-static context, is a compile time known value
154 -- which is outside its range, i.e. the range of Etype. This is used
155 -- in contexts where this is an illegality if N is static, and should
156 -- generate a warning otherwise.
158 procedure Rewrite_In_Raise_CE
(N
: Node_Id
; Exp
: Node_Id
);
159 -- N and Exp are nodes representing an expression, Exp is known
160 -- to raise CE. N is rewritten in term of Exp in the optimal way.
162 function String_Type_Len
(Stype
: Entity_Id
) return Uint
;
163 -- Given a string type, determines the length of the index type, or,
164 -- if this index type is non-static, the length of the base type of
165 -- this index type. Note that if the string type is itself static,
166 -- then the index type is static, so the second case applies only
167 -- if the string type passed is non-static.
169 function Test
(Cond
: Boolean) return Uint
;
170 pragma Inline
(Test
);
171 -- This function simply returns the appropriate Boolean'Pos value
172 -- corresponding to the value of Cond as a universal integer. It is
173 -- used for producing the result of the static evaluation of the
176 procedure Test_Expression_Is_Foldable
181 -- Tests to see if expression N whose single operand is Op1 is foldable,
182 -- i.e. the operand value is known at compile time. If the operation is
183 -- foldable, then Fold is True on return, and Stat indicates whether
184 -- the result is static (i.e. both operands were static). Note that it
185 -- is quite possible for Fold to be True, and Stat to be False, since
186 -- there are cases in which we know the value of an operand even though
187 -- it is not technically static (e.g. the static lower bound of a range
188 -- whose upper bound is non-static).
190 -- If Stat is set False on return, then Expression_Is_Foldable makes a
191 -- call to Check_Non_Static_Context on the operand. If Fold is False on
192 -- return, then all processing is complete, and the caller should
193 -- return, since there is nothing else to do.
195 procedure Test_Expression_Is_Foldable
201 -- Same processing, except applies to an expression N with two operands
204 procedure To_Bits
(U
: Uint
; B
: out Bits
);
205 -- Converts a Uint value to a bit string of length B'Length
207 ------------------------------
208 -- Check_Non_Static_Context --
209 ------------------------------
211 procedure Check_Non_Static_Context
(N
: Node_Id
) is
212 T
: constant Entity_Id
:= Etype
(N
);
213 Checks_On
: constant Boolean :=
214 not Index_Checks_Suppressed
(T
)
215 and not Range_Checks_Suppressed
(T
);
218 -- Ignore cases of non-scalar types or error types
220 if T
= Any_Type
or else not Is_Scalar_Type
(T
) then
224 -- At this stage we have a scalar type. If we have an expression
225 -- that raises CE, then we already issued a warning or error msg
226 -- so there is nothing more to be done in this routine.
228 if Raises_Constraint_Error
(N
) then
232 -- Now we have a scalar type which is not marked as raising a
233 -- constraint error exception. The main purpose of this routine
234 -- is to deal with static expressions appearing in a non-static
235 -- context. That means that if we do not have a static expression
236 -- then there is not much to do. The one case that we deal with
237 -- here is that if we have a floating-point value that is out of
238 -- range, then we post a warning that an infinity will result.
240 if not Is_Static_Expression
(N
) then
241 if Is_Floating_Point_Type
(T
)
242 and then Is_Out_Of_Range
(N
, Base_Type
(T
))
245 ("?float value out of range, infinity will be generated", N
);
251 -- Here we have the case of outer level static expression of
252 -- scalar type, where the processing of this procedure is needed.
254 -- For real types, this is where we convert the value to a machine
255 -- number (see RM 4.9(38)). Also see ACVC test C490001. We should
256 -- only need to do this if the parent is a constant declaration,
257 -- since in other cases, gigi should do the necessary conversion
258 -- correctly, but experimentation shows that this is not the case
259 -- on all machines, in particular if we do not convert all literals
260 -- to machine values in non-static contexts, then ACVC test C490001
261 -- fails on Sparc/Solaris and SGI/Irix.
263 if Nkind
(N
) = N_Real_Literal
264 and then not Is_Machine_Number
(N
)
265 and then not Is_Generic_Type
(Etype
(N
))
266 and then Etype
(N
) /= Universal_Real
268 -- Check that value is in bounds before converting to machine
269 -- number, so as not to lose case where value overflows in the
270 -- least significant bit or less. See B490001.
272 if Is_Out_Of_Range
(N
, Base_Type
(T
)) then
277 -- Note: we have to copy the node, to avoid problems with conformance
278 -- of very similar numbers (see ACVC tests B4A010C and B63103A).
280 Rewrite
(N
, New_Copy
(N
));
282 if not Is_Floating_Point_Type
(T
) then
284 (N
, Corresponding_Integer_Value
(N
) * Small_Value
(T
));
286 elsif not UR_Is_Zero
(Realval
(N
)) then
288 -- Note: even though RM 4.9(38) specifies biased rounding,
289 -- this has been modified by AI-100 in order to prevent
290 -- confusing differences in rounding between static and
291 -- non-static expressions. AI-100 specifies that the effect
292 -- of such rounding is implementation dependent, and in GNAT
293 -- we round to nearest even to match the run-time behavior.
296 (N
, Machine
(Base_Type
(T
), Realval
(N
), Round_Even
, N
));
299 Set_Is_Machine_Number
(N
);
302 -- Check for out of range universal integer. This is a non-static
303 -- context, so the integer value must be in range of the runtime
304 -- representation of universal integers.
306 -- We do this only within an expression, because that is the only
307 -- case in which non-static universal integer values can occur, and
308 -- furthermore, Check_Non_Static_Context is currently (incorrectly???)
309 -- called in contexts like the expression of a number declaration where
310 -- we certainly want to allow out of range values.
312 if Etype
(N
) = Universal_Integer
313 and then Nkind
(N
) = N_Integer_Literal
314 and then Nkind
(Parent
(N
)) in N_Subexpr
316 (Intval
(N
) < Expr_Value
(Type_Low_Bound
(Universal_Integer
))
318 Intval
(N
) > Expr_Value
(Type_High_Bound
(Universal_Integer
)))
320 Apply_Compile_Time_Constraint_Error
321 (N
, "non-static universal integer value out of range?",
322 CE_Range_Check_Failed
);
324 -- Check out of range of base type
326 elsif Is_Out_Of_Range
(N
, Base_Type
(T
)) then
329 -- Give warning if outside subtype (where one or both of the
330 -- bounds of the subtype is static). This warning is omitted
331 -- if the expression appears in a range that could be null
332 -- (warnings are handled elsewhere for this case).
334 elsif T
/= Base_Type
(T
)
335 and then Nkind
(Parent
(N
)) /= N_Range
337 if Is_In_Range
(N
, T
) then
340 elsif Is_Out_Of_Range
(N
, T
) then
341 Apply_Compile_Time_Constraint_Error
342 (N
, "value not in range of}?", CE_Range_Check_Failed
);
345 Enable_Range_Check
(N
);
348 Set_Do_Range_Check
(N
, False);
351 end Check_Non_Static_Context
;
353 ---------------------------------
354 -- Check_String_Literal_Length --
355 ---------------------------------
357 procedure Check_String_Literal_Length
(N
: Node_Id
; Ttype
: Entity_Id
) is
359 if not Raises_Constraint_Error
(N
)
360 and then Is_Constrained
(Ttype
)
363 UI_From_Int
(String_Length
(Strval
(N
))) /= String_Type_Len
(Ttype
)
365 Apply_Compile_Time_Constraint_Error
366 (N
, "string length wrong for}?",
367 CE_Length_Check_Failed
,
372 end Check_String_Literal_Length
;
374 --------------------------
375 -- Compile_Time_Compare --
376 --------------------------
378 function Compile_Time_Compare
380 Rec
: Boolean := False) return Compare_Result
382 Ltyp
: constant Entity_Id
:= Etype
(L
);
383 Rtyp
: constant Entity_Id
:= Etype
(R
);
385 procedure Compare_Decompose
389 -- This procedure decomposes the node N into an expression node
390 -- and a signed offset, so that the value of N is equal to the
391 -- value of R plus the value V (which may be negative). If no
392 -- such decomposition is possible, then on return R is a copy
393 -- of N, and V is set to zero.
395 function Compare_Fixup
(N
: Node_Id
) return Node_Id
;
396 -- This function deals with replacing 'Last and 'First references
397 -- with their corresponding type bounds, which we then can compare.
398 -- The argument is the original node, the result is the identity,
399 -- unless we have a 'Last/'First reference in which case the value
400 -- returned is the appropriate type bound.
402 function Is_Same_Value
(L
, R
: Node_Id
) return Boolean;
403 -- Returns True iff L and R represent expressions that definitely
404 -- have identical (but not necessarily compile time known) values
405 -- Indeed the caller is expected to have already dealt with the
406 -- cases of compile time known values, so these are not tested here.
408 -----------------------
409 -- Compare_Decompose --
410 -----------------------
412 procedure Compare_Decompose
418 if Nkind
(N
) = N_Op_Add
419 and then Nkind
(Right_Opnd
(N
)) = N_Integer_Literal
422 V
:= Intval
(Right_Opnd
(N
));
425 elsif Nkind
(N
) = N_Op_Subtract
426 and then Nkind
(Right_Opnd
(N
)) = N_Integer_Literal
429 V
:= UI_Negate
(Intval
(Right_Opnd
(N
)));
432 elsif Nkind
(N
) = N_Attribute_Reference
then
434 if Attribute_Name
(N
) = Name_Succ
then
435 R
:= First
(Expressions
(N
));
439 elsif Attribute_Name
(N
) = Name_Pred
then
440 R
:= First
(Expressions
(N
));
448 end Compare_Decompose
;
454 function Compare_Fixup
(N
: Node_Id
) return Node_Id
is
460 if Nkind
(N
) = N_Attribute_Reference
461 and then (Attribute_Name
(N
) = Name_First
463 Attribute_Name
(N
) = Name_Last
)
465 Xtyp
:= Etype
(Prefix
(N
));
467 -- If we have no type, then just abandon the attempt to do
468 -- a fixup, this is probably the result of some other error.
474 -- Dereference an access type
476 if Is_Access_Type
(Xtyp
) then
477 Xtyp
:= Designated_Type
(Xtyp
);
480 -- If we don't have an array type at this stage, something
481 -- is peculiar, e.g. another error, and we abandon the attempt
484 if not Is_Array_Type
(Xtyp
) then
488 -- Ignore unconstrained array, since bounds are not meaningful
490 if not Is_Constrained
(Xtyp
) then
494 if Ekind
(Xtyp
) = E_String_Literal_Subtype
then
495 if Attribute_Name
(N
) = Name_First
then
496 return String_Literal_Low_Bound
(Xtyp
);
498 else -- Attribute_Name (N) = Name_Last
499 return Make_Integer_Literal
(Sloc
(N
),
500 Intval
=> Intval
(String_Literal_Low_Bound
(Xtyp
))
501 + String_Literal_Length
(Xtyp
));
505 -- Find correct index type
507 Indx
:= First_Index
(Xtyp
);
509 if Present
(Expressions
(N
)) then
510 Subs
:= UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
512 for J
in 2 .. Subs
loop
513 Indx
:= Next_Index
(Indx
);
517 Xtyp
:= Etype
(Indx
);
519 if Attribute_Name
(N
) = Name_First
then
520 return Type_Low_Bound
(Xtyp
);
522 else -- Attribute_Name (N) = Name_Last
523 return Type_High_Bound
(Xtyp
);
534 function Is_Same_Value
(L
, R
: Node_Id
) return Boolean is
535 Lf
: constant Node_Id
:= Compare_Fixup
(L
);
536 Rf
: constant Node_Id
:= Compare_Fixup
(R
);
538 function Is_Same_Subscript
(L
, R
: List_Id
) return Boolean;
539 -- L, R are the Expressions values from two attribute nodes
540 -- for First or Last attributes. Either may be set to No_List
541 -- if no expressions are present (indicating subscript 1).
542 -- The result is True if both expressions represent the same
543 -- subscript (note that one case is where one subscript is
544 -- missing and the other is explicitly set to 1).
546 -----------------------
547 -- Is_Same_Subscript --
548 -----------------------
550 function Is_Same_Subscript
(L
, R
: List_Id
) return Boolean is
556 return Expr_Value
(First
(R
)) = Uint_1
;
561 return Expr_Value
(First
(L
)) = Uint_1
;
563 return Expr_Value
(First
(L
)) = Expr_Value
(First
(R
));
566 end Is_Same_Subscript
;
568 -- Start of processing for Is_Same_Value
571 -- Values are the same if they are the same identifier and the
572 -- identifier refers to a constant object (E_Constant). This
573 -- does not however apply to Float types, since we may have two
574 -- NaN values and they should never compare equal.
576 if Nkind
(Lf
) = N_Identifier
and then Nkind
(Rf
) = N_Identifier
577 and then Entity
(Lf
) = Entity
(Rf
)
578 and then not Is_Floating_Point_Type
(Etype
(L
))
579 and then (Ekind
(Entity
(Lf
)) = E_Constant
or else
580 Ekind
(Entity
(Lf
)) = E_In_Parameter
or else
581 Ekind
(Entity
(Lf
)) = E_Loop_Parameter
)
585 -- Or if they are compile time known and identical
587 elsif Compile_Time_Known_Value
(Lf
)
589 Compile_Time_Known_Value
(Rf
)
590 and then Expr_Value
(Lf
) = Expr_Value
(Rf
)
594 -- Or if they are both 'First or 'Last values applying to the
595 -- same entity (first and last don't change even if value does)
597 elsif Nkind
(Lf
) = N_Attribute_Reference
599 Nkind
(Rf
) = N_Attribute_Reference
600 and then Attribute_Name
(Lf
) = Attribute_Name
(Rf
)
601 and then (Attribute_Name
(Lf
) = Name_First
603 Attribute_Name
(Lf
) = Name_Last
)
604 and then Is_Entity_Name
(Prefix
(Lf
))
605 and then Is_Entity_Name
(Prefix
(Rf
))
606 and then Entity
(Prefix
(Lf
)) = Entity
(Prefix
(Rf
))
607 and then Is_Same_Subscript
(Expressions
(Lf
), Expressions
(Rf
))
611 -- All other cases, we can't tell
618 -- Start of processing for Compile_Time_Compare
621 -- If either operand could raise constraint error, then we cannot
622 -- know the result at compile time (since CE may be raised!)
624 if not (Cannot_Raise_Constraint_Error
(L
)
626 Cannot_Raise_Constraint_Error
(R
))
631 -- Identical operands are most certainly equal
636 -- If expressions have no types, then do not attempt to determine
637 -- if they are the same, since something funny is going on. One
638 -- case in which this happens is during generic template analysis,
639 -- when bounds are not fully analyzed.
641 elsif No
(Ltyp
) or else No
(Rtyp
) then
644 -- We only attempt compile time analysis for scalar values, and
645 -- not for packed arrays represented as modular types, where the
646 -- semantics of comparison is quite different.
648 elsif not Is_Scalar_Type
(Ltyp
)
649 or else Is_Packed_Array_Type
(Ltyp
)
653 -- Case where comparison involves two compile time known values
655 elsif Compile_Time_Known_Value
(L
)
656 and then Compile_Time_Known_Value
(R
)
658 -- For the floating-point case, we have to be a little careful, since
659 -- at compile time we are dealing with universal exact values, but at
660 -- runtime, these will be in non-exact target form. That's why the
661 -- returned results are LE and GE below instead of LT and GT.
663 if Is_Floating_Point_Type
(Ltyp
)
665 Is_Floating_Point_Type
(Rtyp
)
668 Lo
: constant Ureal
:= Expr_Value_R
(L
);
669 Hi
: constant Ureal
:= Expr_Value_R
(R
);
681 -- For the integer case we know exactly (note that this includes the
682 -- fixed-point case, where we know the run time integer values now)
686 Lo
: constant Uint
:= Expr_Value
(L
);
687 Hi
: constant Uint
:= Expr_Value
(R
);
700 -- Cases where at least one operand is not known at compile time
703 -- Here is where we check for comparisons against maximum bounds of
704 -- types, where we know that no value can be outside the bounds of
705 -- the subtype. Note that this routine is allowed to assume that all
706 -- expressions are within their subtype bounds. Callers wishing to
707 -- deal with possibly invalid values must in any case take special
708 -- steps (e.g. conversions to larger types) to avoid this kind of
709 -- optimization, which is always considered to be valid. We do not
710 -- attempt this optimization with generic types, since the type
711 -- bounds may not be meaningful in this case.
713 -- We are in danger of an infinite recursion here. It does not seem
714 -- useful to go more than one level deep, so the parameter Rec is
715 -- used to protect ourselves against this infinite recursion.
718 and then Is_Discrete_Type
(Ltyp
)
719 and then Is_Discrete_Type
(Rtyp
)
720 and then not Is_Generic_Type
(Ltyp
)
721 and then not Is_Generic_Type
(Rtyp
)
723 -- See if we can get a decisive check against one operand and
724 -- a bound of the other operand (four possible tests here).
726 case Compile_Time_Compare
(L
, Type_Low_Bound
(Rtyp
), True) is
727 when LT
=> return LT
;
728 when LE
=> return LE
;
729 when EQ
=> return LE
;
733 case Compile_Time_Compare
(L
, Type_High_Bound
(Rtyp
), True) is
734 when GT
=> return GT
;
735 when GE
=> return GE
;
736 when EQ
=> return GE
;
740 case Compile_Time_Compare
(Type_Low_Bound
(Ltyp
), R
, True) is
741 when GT
=> return GT
;
742 when GE
=> return GE
;
743 when EQ
=> return GE
;
747 case Compile_Time_Compare
(Type_High_Bound
(Ltyp
), R
, True) is
748 when LT
=> return LT
;
749 when LE
=> return LE
;
750 when EQ
=> return LE
;
755 -- Next attempt is to decompose the expressions to extract
756 -- a constant offset resulting from the use of any of the forms:
763 -- Then we see if the two expressions are the same value, and if so
764 -- the result is obtained by comparing the offsets.
773 Compare_Decompose
(L
, Lnode
, Loffs
);
774 Compare_Decompose
(R
, Rnode
, Roffs
);
776 if Is_Same_Value
(Lnode
, Rnode
) then
777 if Loffs
= Roffs
then
780 elsif Loffs
< Roffs
then
787 -- If the expressions are different, we cannot say at compile
788 -- time how they compare, so we return the Unknown indication.
795 end Compile_Time_Compare
;
797 -------------------------------
798 -- Compile_Time_Known_Bounds --
799 -------------------------------
801 function Compile_Time_Known_Bounds
(T
: Entity_Id
) return Boolean is
806 if not Is_Array_Type
(T
) then
810 Indx
:= First_Index
(T
);
811 while Present
(Indx
) loop
812 Typ
:= Underlying_Type
(Etype
(Indx
));
813 if not Compile_Time_Known_Value
(Type_Low_Bound
(Typ
)) then
815 elsif not Compile_Time_Known_Value
(Type_High_Bound
(Typ
)) then
823 end Compile_Time_Known_Bounds
;
825 ------------------------------
826 -- Compile_Time_Known_Value --
827 ------------------------------
829 function Compile_Time_Known_Value
(Op
: Node_Id
) return Boolean is
830 K
: constant Node_Kind
:= Nkind
(Op
);
831 CV_Ent
: CV_Entry
renames CV_Cache
(Nat
(Op
) mod CV_Cache_Size
);
834 -- Never known at compile time if bad type or raises constraint error
835 -- or empty (latter case occurs only as a result of a previous error)
839 or else Etype
(Op
) = Any_Type
840 or else Raises_Constraint_Error
(Op
)
845 -- If this is not a static expression and we are in configurable run
846 -- time mode, then we consider it not known at compile time. This
847 -- avoids anomalies where whether something is permitted with a given
848 -- configurable run-time library depends on how good the compiler is
849 -- at optimizing and knowing that things are constant when they
852 if Configurable_Run_Time_Mode
and then not Is_Static_Expression
(Op
) then
856 -- If we have an entity name, then see if it is the name of a constant
857 -- and if so, test the corresponding constant value, or the name of
858 -- an enumeration literal, which is always a constant.
860 if Present
(Etype
(Op
)) and then Is_Entity_Name
(Op
) then
862 E
: constant Entity_Id
:= Entity
(Op
);
866 -- Never known at compile time if it is a packed array value.
867 -- We might want to try to evaluate these at compile time one
868 -- day, but we do not make that attempt now.
870 if Is_Packed_Array_Type
(Etype
(Op
)) then
874 if Ekind
(E
) = E_Enumeration_Literal
then
877 elsif Ekind
(E
) = E_Constant
then
878 V
:= Constant_Value
(E
);
879 return Present
(V
) and then Compile_Time_Known_Value
(V
);
883 -- We have a value, see if it is compile time known
886 -- Integer literals are worth storing in the cache
888 if K
= N_Integer_Literal
then
890 CV_Ent
.V
:= Intval
(Op
);
893 -- Other literals and NULL are known at compile time
896 K
= N_Character_Literal
906 -- Any reference to Null_Parameter is known at compile time. No
907 -- other attribute references (that have not already been folded)
908 -- are known at compile time.
910 elsif K
= N_Attribute_Reference
then
911 return Attribute_Name
(Op
) = Name_Null_Parameter
;
915 -- If we fall through, not known at compile time
919 -- If we get an exception while trying to do this test, then some error
920 -- has occurred, and we simply say that the value is not known after all
925 end Compile_Time_Known_Value
;
927 --------------------------------------
928 -- Compile_Time_Known_Value_Or_Aggr --
929 --------------------------------------
931 function Compile_Time_Known_Value_Or_Aggr
(Op
: Node_Id
) return Boolean is
933 -- If we have an entity name, then see if it is the name of a constant
934 -- and if so, test the corresponding constant value, or the name of
935 -- an enumeration literal, which is always a constant.
937 if Is_Entity_Name
(Op
) then
939 E
: constant Entity_Id
:= Entity
(Op
);
943 if Ekind
(E
) = E_Enumeration_Literal
then
946 elsif Ekind
(E
) /= E_Constant
then
950 V
:= Constant_Value
(E
);
952 and then Compile_Time_Known_Value_Or_Aggr
(V
);
956 -- We have a value, see if it is compile time known
959 if Compile_Time_Known_Value
(Op
) then
962 elsif Nkind
(Op
) = N_Aggregate
then
964 if Present
(Expressions
(Op
)) then
969 Expr
:= First
(Expressions
(Op
));
970 while Present
(Expr
) loop
971 if not Compile_Time_Known_Value_Or_Aggr
(Expr
) then
980 if Present
(Component_Associations
(Op
)) then
985 Cass
:= First
(Component_Associations
(Op
));
986 while Present
(Cass
) loop
988 Compile_Time_Known_Value_Or_Aggr
(Expression
(Cass
))
1000 -- All other types of values are not known at compile time
1007 end Compile_Time_Known_Value_Or_Aggr
;
1013 -- This is only called for actuals of functions that are not predefined
1014 -- operators (which have already been rewritten as operators at this
1015 -- stage), so the call can never be folded, and all that needs doing for
1016 -- the actual is to do the check for a non-static context.
1018 procedure Eval_Actual
(N
: Node_Id
) is
1020 Check_Non_Static_Context
(N
);
1023 --------------------
1024 -- Eval_Allocator --
1025 --------------------
1027 -- Allocators are never static, so all we have to do is to do the
1028 -- check for a non-static context if an expression is present.
1030 procedure Eval_Allocator
(N
: Node_Id
) is
1031 Expr
: constant Node_Id
:= Expression
(N
);
1034 if Nkind
(Expr
) = N_Qualified_Expression
then
1035 Check_Non_Static_Context
(Expression
(Expr
));
1039 ------------------------
1040 -- Eval_Arithmetic_Op --
1041 ------------------------
1043 -- Arithmetic operations are static functions, so the result is static
1044 -- if both operands are static (RM 4.9(7), 4.9(20)).
1046 procedure Eval_Arithmetic_Op
(N
: Node_Id
) is
1047 Left
: constant Node_Id
:= Left_Opnd
(N
);
1048 Right
: constant Node_Id
:= Right_Opnd
(N
);
1049 Ltype
: constant Entity_Id
:= Etype
(Left
);
1050 Rtype
: constant Entity_Id
:= Etype
(Right
);
1055 -- If not foldable we are done
1057 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
1063 -- Fold for cases where both operands are of integer type
1065 if Is_Integer_Type
(Ltype
) and then Is_Integer_Type
(Rtype
) then
1067 Left_Int
: constant Uint
:= Expr_Value
(Left
);
1068 Right_Int
: constant Uint
:= Expr_Value
(Right
);
1075 Result
:= Left_Int
+ Right_Int
;
1077 when N_Op_Subtract
=>
1078 Result
:= Left_Int
- Right_Int
;
1080 when N_Op_Multiply
=>
1083 (Num_Bits
(Left_Int
) + Num_Bits
(Right_Int
)))
1085 Result
:= Left_Int
* Right_Int
;
1092 -- The exception Constraint_Error is raised by integer
1093 -- division, rem and mod if the right operand is zero.
1095 if Right_Int
= 0 then
1096 Apply_Compile_Time_Constraint_Error
1097 (N
, "division by zero",
1103 Result
:= Left_Int
/ Right_Int
;
1108 -- The exception Constraint_Error is raised by integer
1109 -- division, rem and mod if the right operand is zero.
1111 if Right_Int
= 0 then
1112 Apply_Compile_Time_Constraint_Error
1113 (N
, "mod with zero divisor",
1118 Result
:= Left_Int
mod Right_Int
;
1123 -- The exception Constraint_Error is raised by integer
1124 -- division, rem and mod if the right operand is zero.
1126 if Right_Int
= 0 then
1127 Apply_Compile_Time_Constraint_Error
1128 (N
, "rem with zero divisor",
1134 Result
:= Left_Int
rem Right_Int
;
1138 raise Program_Error
;
1141 -- Adjust the result by the modulus if the type is a modular type
1143 if Is_Modular_Integer_Type
(Ltype
) then
1144 Result
:= Result
mod Modulus
(Ltype
);
1146 -- For a signed integer type, check non-static overflow
1148 elsif (not Stat
) and then Is_Signed_Integer_Type
(Ltype
) then
1150 BT
: constant Entity_Id
:= Base_Type
(Ltype
);
1151 Lo
: constant Uint
:= Expr_Value
(Type_Low_Bound
(BT
));
1152 Hi
: constant Uint
:= Expr_Value
(Type_High_Bound
(BT
));
1154 if Result
< Lo
or else Result
> Hi
then
1155 Apply_Compile_Time_Constraint_Error
1156 (N
, "value not in range of }?",
1157 CE_Overflow_Check_Failed
,
1164 -- If we get here we can fold the result
1166 Fold_Uint
(N
, Result
, Stat
);
1169 -- Cases where at least one operand is a real. We handle the cases
1170 -- of both reals, or mixed/real integer cases (the latter happen
1171 -- only for divide and multiply, and the result is always real).
1173 elsif Is_Real_Type
(Ltype
) or else Is_Real_Type
(Rtype
) then
1180 if Is_Real_Type
(Ltype
) then
1181 Left_Real
:= Expr_Value_R
(Left
);
1183 Left_Real
:= UR_From_Uint
(Expr_Value
(Left
));
1186 if Is_Real_Type
(Rtype
) then
1187 Right_Real
:= Expr_Value_R
(Right
);
1189 Right_Real
:= UR_From_Uint
(Expr_Value
(Right
));
1192 if Nkind
(N
) = N_Op_Add
then
1193 Result
:= Left_Real
+ Right_Real
;
1195 elsif Nkind
(N
) = N_Op_Subtract
then
1196 Result
:= Left_Real
- Right_Real
;
1198 elsif Nkind
(N
) = N_Op_Multiply
then
1199 Result
:= Left_Real
* Right_Real
;
1201 else pragma Assert
(Nkind
(N
) = N_Op_Divide
);
1202 if UR_Is_Zero
(Right_Real
) then
1203 Apply_Compile_Time_Constraint_Error
1204 (N
, "division by zero", CE_Divide_By_Zero
);
1208 Result
:= Left_Real
/ Right_Real
;
1211 Fold_Ureal
(N
, Result
, Stat
);
1214 end Eval_Arithmetic_Op
;
1216 ----------------------------
1217 -- Eval_Character_Literal --
1218 ----------------------------
1220 -- Nothing to be done!
1222 procedure Eval_Character_Literal
(N
: Node_Id
) is
1223 pragma Warnings
(Off
, N
);
1226 end Eval_Character_Literal
;
1232 -- Static function calls are either calls to predefined operators
1233 -- with static arguments, or calls to functions that rename a literal.
1234 -- Only the latter case is handled here, predefined operators are
1235 -- constant-folded elsewhere.
1236 -- If the function is itself inherited (see 7423-001) the literal of
1237 -- the parent type must be explicitly converted to the return type
1240 procedure Eval_Call
(N
: Node_Id
) is
1241 Loc
: constant Source_Ptr
:= Sloc
(N
);
1242 Typ
: constant Entity_Id
:= Etype
(N
);
1246 if Nkind
(N
) = N_Function_Call
1247 and then No
(Parameter_Associations
(N
))
1248 and then Is_Entity_Name
(Name
(N
))
1249 and then Present
(Alias
(Entity
(Name
(N
))))
1250 and then Is_Enumeration_Type
(Base_Type
(Typ
))
1252 Lit
:= Alias
(Entity
(Name
(N
)));
1254 while Present
(Alias
(Lit
)) loop
1258 if Ekind
(Lit
) = E_Enumeration_Literal
then
1259 if Base_Type
(Etype
(Lit
)) /= Base_Type
(Typ
) then
1261 (N
, Convert_To
(Typ
, New_Occurrence_Of
(Lit
, Loc
)));
1263 Rewrite
(N
, New_Occurrence_Of
(Lit
, Loc
));
1271 ------------------------
1272 -- Eval_Concatenation --
1273 ------------------------
1275 -- Concatenation is a static function, so the result is static if
1276 -- both operands are static (RM 4.9(7), 4.9(21)).
1278 procedure Eval_Concatenation
(N
: Node_Id
) is
1279 Left
: constant Node_Id
:= Left_Opnd
(N
);
1280 Right
: constant Node_Id
:= Right_Opnd
(N
);
1281 C_Typ
: constant Entity_Id
:= Root_Type
(Component_Type
(Etype
(N
)));
1286 -- Concatenation is never static in Ada 83, so if Ada 83
1287 -- check operand non-static context
1289 if Ada_Version
= Ada_83
1290 and then Comes_From_Source
(N
)
1292 Check_Non_Static_Context
(Left
);
1293 Check_Non_Static_Context
(Right
);
1297 -- If not foldable we are done. In principle concatenation that yields
1298 -- any string type is static (i.e. an array type of character types).
1299 -- However, character types can include enumeration literals, and
1300 -- concatenation in that case cannot be described by a literal, so we
1301 -- only consider the operation static if the result is an array of
1302 -- (a descendant of) a predefined character type.
1304 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
1306 if (C_Typ
= Standard_Character
1307 or else C_Typ
= Standard_Wide_Character
1308 or else C_Typ
= Standard_Wide_Wide_Character
)
1313 Set_Is_Static_Expression
(N
, False);
1317 -- Compile time string concatenation
1319 -- ??? Note that operands that are aggregates can be marked as
1320 -- static, so we should attempt at a later stage to fold
1321 -- concatenations with such aggregates.
1324 Left_Str
: constant Node_Id
:= Get_String_Val
(Left
);
1326 Right_Str
: constant Node_Id
:= Get_String_Val
(Right
);
1329 -- Establish new string literal, and store left operand. We make
1330 -- sure to use the special Start_String that takes an operand if
1331 -- the left operand is a string literal. Since this is optimized
1332 -- in the case where that is the most recently created string
1333 -- literal, we ensure efficient time/space behavior for the
1334 -- case of a concatenation of a series of string literals.
1336 if Nkind
(Left_Str
) = N_String_Literal
then
1337 Left_Len
:= String_Length
(Strval
(Left_Str
));
1338 Start_String
(Strval
(Left_Str
));
1341 Store_String_Char
(UI_To_CC
(Char_Literal_Value
(Left_Str
)));
1345 -- Now append the characters of the right operand
1347 if Nkind
(Right_Str
) = N_String_Literal
then
1349 S
: constant String_Id
:= Strval
(Right_Str
);
1352 for J
in 1 .. String_Length
(S
) loop
1353 Store_String_Char
(Get_String_Char
(S
, J
));
1357 Store_String_Char
(UI_To_CC
(Char_Literal_Value
(Right_Str
)));
1360 Set_Is_Static_Expression
(N
, Stat
);
1364 -- If left operand is the empty string, the result is the
1365 -- right operand, including its bounds if anomalous.
1368 and then Is_Array_Type
(Etype
(Right
))
1369 and then Etype
(Right
) /= Any_String
1371 Set_Etype
(N
, Etype
(Right
));
1374 Fold_Str
(N
, End_String
, True);
1377 end Eval_Concatenation
;
1379 ---------------------------------
1380 -- Eval_Conditional_Expression --
1381 ---------------------------------
1383 -- This GNAT internal construct can never be statically folded, so the
1384 -- only required processing is to do the check for non-static context
1385 -- for the two expression operands.
1387 procedure Eval_Conditional_Expression
(N
: Node_Id
) is
1388 Condition
: constant Node_Id
:= First
(Expressions
(N
));
1389 Then_Expr
: constant Node_Id
:= Next
(Condition
);
1390 Else_Expr
: constant Node_Id
:= Next
(Then_Expr
);
1393 Check_Non_Static_Context
(Then_Expr
);
1394 Check_Non_Static_Context
(Else_Expr
);
1395 end Eval_Conditional_Expression
;
1397 ----------------------
1398 -- Eval_Entity_Name --
1399 ----------------------
1401 -- This procedure is used for identifiers and expanded names other than
1402 -- named numbers (see Eval_Named_Integer, Eval_Named_Real. These are
1403 -- static if they denote a static constant (RM 4.9(6)) or if the name
1404 -- denotes an enumeration literal (RM 4.9(22)).
1406 procedure Eval_Entity_Name
(N
: Node_Id
) is
1407 Def_Id
: constant Entity_Id
:= Entity
(N
);
1411 -- Enumeration literals are always considered to be constants
1412 -- and cannot raise constraint error (RM 4.9(22)).
1414 if Ekind
(Def_Id
) = E_Enumeration_Literal
then
1415 Set_Is_Static_Expression
(N
);
1418 -- A name is static if it denotes a static constant (RM 4.9(5)), and
1419 -- we also copy Raise_Constraint_Error. Notice that even if non-static,
1420 -- it does not violate 10.2.1(8) here, since this is not a variable.
1422 elsif Ekind
(Def_Id
) = E_Constant
then
1424 -- Deferred constants must always be treated as nonstatic
1425 -- outside the scope of their full view.
1427 if Present
(Full_View
(Def_Id
))
1428 and then not In_Open_Scopes
(Scope
(Def_Id
))
1432 Val
:= Constant_Value
(Def_Id
);
1435 if Present
(Val
) then
1436 Set_Is_Static_Expression
1437 (N
, Is_Static_Expression
(Val
)
1438 and then Is_Static_Subtype
(Etype
(Def_Id
)));
1439 Set_Raises_Constraint_Error
(N
, Raises_Constraint_Error
(Val
));
1441 if not Is_Static_Expression
(N
)
1442 and then not Is_Generic_Type
(Etype
(N
))
1444 Validate_Static_Object_Name
(N
);
1451 -- Fall through if the name is not static
1453 Validate_Static_Object_Name
(N
);
1454 end Eval_Entity_Name
;
1456 ----------------------------
1457 -- Eval_Indexed_Component --
1458 ----------------------------
1460 -- Indexed components are never static, so we need to perform the check
1461 -- for non-static context on the index values. Then, we check if the
1462 -- value can be obtained at compile time, even though it is non-static.
1464 procedure Eval_Indexed_Component
(N
: Node_Id
) is
1468 -- Check for non-static context on index values
1470 Expr
:= First
(Expressions
(N
));
1471 while Present
(Expr
) loop
1472 Check_Non_Static_Context
(Expr
);
1476 -- If the indexed component appears in an object renaming declaration
1477 -- then we do not want to try to evaluate it, since in this case we
1478 -- need the identity of the array element.
1480 if Nkind
(Parent
(N
)) = N_Object_Renaming_Declaration
then
1483 -- Similarly if the indexed component appears as the prefix of an
1484 -- attribute we don't want to evaluate it, because at least for
1485 -- some cases of attributes we need the identify (e.g. Access, Size)
1487 elsif Nkind
(Parent
(N
)) = N_Attribute_Reference
then
1491 -- Note: there are other cases, such as the left side of an assignment,
1492 -- or an OUT parameter for a call, where the replacement results in the
1493 -- illegal use of a constant, But these cases are illegal in the first
1494 -- place, so the replacement, though silly, is harmless.
1496 -- Now see if this is a constant array reference
1498 if List_Length
(Expressions
(N
)) = 1
1499 and then Is_Entity_Name
(Prefix
(N
))
1500 and then Ekind
(Entity
(Prefix
(N
))) = E_Constant
1501 and then Present
(Constant_Value
(Entity
(Prefix
(N
))))
1504 Loc
: constant Source_Ptr
:= Sloc
(N
);
1505 Arr
: constant Node_Id
:= Constant_Value
(Entity
(Prefix
(N
)));
1506 Sub
: constant Node_Id
:= First
(Expressions
(N
));
1512 -- Linear one's origin subscript value for array reference
1515 -- Lower bound of the first array index
1518 -- Value from constant array
1521 Atyp
:= Etype
(Arr
);
1523 if Is_Access_Type
(Atyp
) then
1524 Atyp
:= Designated_Type
(Atyp
);
1527 -- If we have an array type (we should have but perhaps there
1528 -- are error cases where this is not the case), then see if we
1529 -- can do a constant evaluation of the array reference.
1531 if Is_Array_Type
(Atyp
) then
1532 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
1533 Lbd
:= String_Literal_Low_Bound
(Atyp
);
1535 Lbd
:= Type_Low_Bound
(Etype
(First_Index
(Atyp
)));
1538 if Compile_Time_Known_Value
(Sub
)
1539 and then Nkind
(Arr
) = N_Aggregate
1540 and then Compile_Time_Known_Value
(Lbd
)
1541 and then Is_Discrete_Type
(Component_Type
(Atyp
))
1543 Lin
:= UI_To_Int
(Expr_Value
(Sub
) - Expr_Value
(Lbd
)) + 1;
1545 if List_Length
(Expressions
(Arr
)) >= Lin
then
1546 Elm
:= Pick
(Expressions
(Arr
), Lin
);
1548 -- If the resulting expression is compile time known,
1549 -- then we can rewrite the indexed component with this
1550 -- value, being sure to mark the result as non-static.
1551 -- We also reset the Sloc, in case this generates an
1552 -- error later on (e.g. 136'Access).
1554 if Compile_Time_Known_Value
(Elm
) then
1555 Rewrite
(N
, Duplicate_Subexpr_No_Checks
(Elm
));
1556 Set_Is_Static_Expression
(N
, False);
1564 end Eval_Indexed_Component
;
1566 --------------------------
1567 -- Eval_Integer_Literal --
1568 --------------------------
1570 -- Numeric literals are static (RM 4.9(1)), and have already been marked
1571 -- as static by the analyzer. The reason we did it that early is to allow
1572 -- the possibility of turning off the Is_Static_Expression flag after
1573 -- analysis, but before resolution, when integer literals are generated
1574 -- in the expander that do not correspond to static expressions.
1576 procedure Eval_Integer_Literal
(N
: Node_Id
) is
1577 T
: constant Entity_Id
:= Etype
(N
);
1579 function In_Any_Integer_Context
return Boolean;
1580 -- If the literal is resolved with a specific type in a context
1581 -- where the expected type is Any_Integer, there are no range checks
1582 -- on the literal. By the time the literal is evaluated, it carries
1583 -- the type imposed by the enclosing expression, and we must recover
1584 -- the context to determine that Any_Integer is meant.
1586 ----------------------------
1587 -- To_Any_Integer_Context --
1588 ----------------------------
1590 function In_Any_Integer_Context
return Boolean is
1591 Par
: constant Node_Id
:= Parent
(N
);
1592 K
: constant Node_Kind
:= Nkind
(Par
);
1595 -- Any_Integer also appears in digits specifications for real types,
1596 -- but those have bounds smaller that those of any integer base
1597 -- type, so we can safely ignore these cases.
1599 return K
= N_Number_Declaration
1600 or else K
= N_Attribute_Reference
1601 or else K
= N_Attribute_Definition_Clause
1602 or else K
= N_Modular_Type_Definition
1603 or else K
= N_Signed_Integer_Type_Definition
;
1604 end In_Any_Integer_Context
;
1606 -- Start of processing for Eval_Integer_Literal
1610 -- If the literal appears in a non-expression context, then it is
1611 -- certainly appearing in a non-static context, so check it. This
1612 -- is actually a redundant check, since Check_Non_Static_Context
1613 -- would check it, but it seems worth while avoiding the call.
1615 if Nkind
(Parent
(N
)) not in N_Subexpr
1616 and then not In_Any_Integer_Context
1618 Check_Non_Static_Context
(N
);
1621 -- Modular integer literals must be in their base range
1623 if Is_Modular_Integer_Type
(T
)
1624 and then Is_Out_Of_Range
(N
, Base_Type
(T
))
1628 end Eval_Integer_Literal
;
1630 ---------------------
1631 -- Eval_Logical_Op --
1632 ---------------------
1634 -- Logical operations are static functions, so the result is potentially
1635 -- static if both operands are potentially static (RM 4.9(7), 4.9(20)).
1637 procedure Eval_Logical_Op
(N
: Node_Id
) is
1638 Left
: constant Node_Id
:= Left_Opnd
(N
);
1639 Right
: constant Node_Id
:= Right_Opnd
(N
);
1644 -- If not foldable we are done
1646 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
1652 -- Compile time evaluation of logical operation
1655 Left_Int
: constant Uint
:= Expr_Value
(Left
);
1656 Right_Int
: constant Uint
:= Expr_Value
(Right
);
1659 if Is_Modular_Integer_Type
(Etype
(N
)) then
1661 Left_Bits
: Bits
(0 .. UI_To_Int
(Esize
(Etype
(N
))) - 1);
1662 Right_Bits
: Bits
(0 .. UI_To_Int
(Esize
(Etype
(N
))) - 1);
1665 To_Bits
(Left_Int
, Left_Bits
);
1666 To_Bits
(Right_Int
, Right_Bits
);
1668 -- Note: should really be able to use array ops instead of
1669 -- these loops, but they weren't working at the time ???
1671 if Nkind
(N
) = N_Op_And
then
1672 for J
in Left_Bits
'Range loop
1673 Left_Bits
(J
) := Left_Bits
(J
) and Right_Bits
(J
);
1676 elsif Nkind
(N
) = N_Op_Or
then
1677 for J
in Left_Bits
'Range loop
1678 Left_Bits
(J
) := Left_Bits
(J
) or Right_Bits
(J
);
1682 pragma Assert
(Nkind
(N
) = N_Op_Xor
);
1684 for J
in Left_Bits
'Range loop
1685 Left_Bits
(J
) := Left_Bits
(J
) xor Right_Bits
(J
);
1689 Fold_Uint
(N
, From_Bits
(Left_Bits
, Etype
(N
)), Stat
);
1693 pragma Assert
(Is_Boolean_Type
(Etype
(N
)));
1695 if Nkind
(N
) = N_Op_And
then
1697 Test
(Is_True
(Left_Int
) and then Is_True
(Right_Int
)), Stat
);
1699 elsif Nkind
(N
) = N_Op_Or
then
1701 Test
(Is_True
(Left_Int
) or else Is_True
(Right_Int
)), Stat
);
1704 pragma Assert
(Nkind
(N
) = N_Op_Xor
);
1706 Test
(Is_True
(Left_Int
) xor Is_True
(Right_Int
)), Stat
);
1710 end Eval_Logical_Op
;
1712 ------------------------
1713 -- Eval_Membership_Op --
1714 ------------------------
1716 -- A membership test is potentially static if the expression is static,
1717 -- and the range is a potentially static range, or is a subtype mark
1718 -- denoting a static subtype (RM 4.9(12)).
1720 procedure Eval_Membership_Op
(N
: Node_Id
) is
1721 Left
: constant Node_Id
:= Left_Opnd
(N
);
1722 Right
: constant Node_Id
:= Right_Opnd
(N
);
1731 -- Ignore if error in either operand, except to make sure that
1732 -- Any_Type is properly propagated to avoid junk cascaded errors.
1734 if Etype
(Left
) = Any_Type
1735 or else Etype
(Right
) = Any_Type
1737 Set_Etype
(N
, Any_Type
);
1741 -- Case of right operand is a subtype name
1743 if Is_Entity_Name
(Right
) then
1744 Def_Id
:= Entity
(Right
);
1746 if (Is_Scalar_Type
(Def_Id
) or else Is_String_Type
(Def_Id
))
1747 and then Is_OK_Static_Subtype
(Def_Id
)
1749 Test_Expression_Is_Foldable
(N
, Left
, Stat
, Fold
);
1751 if not Fold
or else not Stat
then
1755 Check_Non_Static_Context
(Left
);
1759 -- For string membership tests we will check the length
1762 if not Is_String_Type
(Def_Id
) then
1763 Lo
:= Type_Low_Bound
(Def_Id
);
1764 Hi
:= Type_High_Bound
(Def_Id
);
1771 -- Case of right operand is a range
1774 if Is_Static_Range
(Right
) then
1775 Test_Expression_Is_Foldable
(N
, Left
, Stat
, Fold
);
1777 if not Fold
or else not Stat
then
1780 -- If one bound of range raises CE, then don't try to fold
1782 elsif not Is_OK_Static_Range
(Right
) then
1783 Check_Non_Static_Context
(Left
);
1788 Check_Non_Static_Context
(Left
);
1792 -- Here we know range is an OK static range
1794 Lo
:= Low_Bound
(Right
);
1795 Hi
:= High_Bound
(Right
);
1798 -- For strings we check that the length of the string expression is
1799 -- compatible with the string subtype if the subtype is constrained,
1800 -- or if unconstrained then the test is always true.
1802 if Is_String_Type
(Etype
(Right
)) then
1803 if not Is_Constrained
(Etype
(Right
)) then
1808 Typlen
: constant Uint
:= String_Type_Len
(Etype
(Right
));
1809 Strlen
: constant Uint
:=
1810 UI_From_Int
(String_Length
(Strval
(Get_String_Val
(Left
))));
1812 Result
:= (Typlen
= Strlen
);
1816 -- Fold the membership test. We know we have a static range and Lo
1817 -- and Hi are set to the expressions for the end points of this range.
1819 elsif Is_Real_Type
(Etype
(Right
)) then
1821 Leftval
: constant Ureal
:= Expr_Value_R
(Left
);
1824 Result
:= Expr_Value_R
(Lo
) <= Leftval
1825 and then Leftval
<= Expr_Value_R
(Hi
);
1830 Leftval
: constant Uint
:= Expr_Value
(Left
);
1833 Result
:= Expr_Value
(Lo
) <= Leftval
1834 and then Leftval
<= Expr_Value
(Hi
);
1838 if Nkind
(N
) = N_Not_In
then
1839 Result
:= not Result
;
1842 Fold_Uint
(N
, Test
(Result
), True);
1843 Warn_On_Known_Condition
(N
);
1844 end Eval_Membership_Op
;
1846 ------------------------
1847 -- Eval_Named_Integer --
1848 ------------------------
1850 procedure Eval_Named_Integer
(N
: Node_Id
) is
1853 Expr_Value
(Expression
(Declaration_Node
(Entity
(N
)))), True);
1854 end Eval_Named_Integer
;
1856 ---------------------
1857 -- Eval_Named_Real --
1858 ---------------------
1860 procedure Eval_Named_Real
(N
: Node_Id
) is
1863 Expr_Value_R
(Expression
(Declaration_Node
(Entity
(N
)))), True);
1864 end Eval_Named_Real
;
1870 -- Exponentiation is a static functions, so the result is potentially
1871 -- static if both operands are potentially static (RM 4.9(7), 4.9(20)).
1873 procedure Eval_Op_Expon
(N
: Node_Id
) is
1874 Left
: constant Node_Id
:= Left_Opnd
(N
);
1875 Right
: constant Node_Id
:= Right_Opnd
(N
);
1880 -- If not foldable we are done
1882 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
1888 -- Fold exponentiation operation
1891 Right_Int
: constant Uint
:= Expr_Value
(Right
);
1896 if Is_Integer_Type
(Etype
(Left
)) then
1898 Left_Int
: constant Uint
:= Expr_Value
(Left
);
1902 -- Exponentiation of an integer raises the exception
1903 -- Constraint_Error for a negative exponent (RM 4.5.6)
1905 if Right_Int
< 0 then
1906 Apply_Compile_Time_Constraint_Error
1907 (N
, "integer exponent negative",
1908 CE_Range_Check_Failed
,
1913 if OK_Bits
(N
, Num_Bits
(Left_Int
) * Right_Int
) then
1914 Result
:= Left_Int
** Right_Int
;
1919 if Is_Modular_Integer_Type
(Etype
(N
)) then
1920 Result
:= Result
mod Modulus
(Etype
(N
));
1923 Fold_Uint
(N
, Result
, Stat
);
1931 Left_Real
: constant Ureal
:= Expr_Value_R
(Left
);
1934 -- Cannot have a zero base with a negative exponent
1936 if UR_Is_Zero
(Left_Real
) then
1938 if Right_Int
< 0 then
1939 Apply_Compile_Time_Constraint_Error
1940 (N
, "zero ** negative integer",
1941 CE_Range_Check_Failed
,
1945 Fold_Ureal
(N
, Ureal_0
, Stat
);
1949 Fold_Ureal
(N
, Left_Real
** Right_Int
, Stat
);
1960 -- The not operation is a static functions, so the result is potentially
1961 -- static if the operand is potentially static (RM 4.9(7), 4.9(20)).
1963 procedure Eval_Op_Not
(N
: Node_Id
) is
1964 Right
: constant Node_Id
:= Right_Opnd
(N
);
1969 -- If not foldable we are done
1971 Test_Expression_Is_Foldable
(N
, Right
, Stat
, Fold
);
1977 -- Fold not operation
1980 Rint
: constant Uint
:= Expr_Value
(Right
);
1981 Typ
: constant Entity_Id
:= Etype
(N
);
1984 -- Negation is equivalent to subtracting from the modulus minus
1985 -- one. For a binary modulus this is equivalent to the ones-
1986 -- component of the original value. For non-binary modulus this
1987 -- is an arbitrary but consistent definition.
1989 if Is_Modular_Integer_Type
(Typ
) then
1990 Fold_Uint
(N
, Modulus
(Typ
) - 1 - Rint
, Stat
);
1993 pragma Assert
(Is_Boolean_Type
(Typ
));
1994 Fold_Uint
(N
, Test
(not Is_True
(Rint
)), Stat
);
1997 Set_Is_Static_Expression
(N
, Stat
);
2001 -------------------------------
2002 -- Eval_Qualified_Expression --
2003 -------------------------------
2005 -- A qualified expression is potentially static if its subtype mark denotes
2006 -- a static subtype and its expression is potentially static (RM 4.9 (11)).
2008 procedure Eval_Qualified_Expression
(N
: Node_Id
) is
2009 Operand
: constant Node_Id
:= Expression
(N
);
2010 Target_Type
: constant Entity_Id
:= Entity
(Subtype_Mark
(N
));
2017 -- Can only fold if target is string or scalar and subtype is static
2018 -- Also, do not fold if our parent is an allocator (this is because
2019 -- the qualified expression is really part of the syntactic structure
2020 -- of an allocator, and we do not want to end up with something that
2021 -- corresponds to "new 1" where the 1 is the result of folding a
2022 -- qualified expression).
2024 if not Is_Static_Subtype
(Target_Type
)
2025 or else Nkind
(Parent
(N
)) = N_Allocator
2027 Check_Non_Static_Context
(Operand
);
2029 -- If operand is known to raise constraint_error, set the
2030 -- flag on the expression so it does not get optimized away.
2032 if Nkind
(Operand
) = N_Raise_Constraint_Error
then
2033 Set_Raises_Constraint_Error
(N
);
2039 -- If not foldable we are done
2041 Test_Expression_Is_Foldable
(N
, Operand
, Stat
, Fold
);
2046 -- Don't try fold if target type has constraint error bounds
2048 elsif not Is_OK_Static_Subtype
(Target_Type
) then
2049 Set_Raises_Constraint_Error
(N
);
2053 -- Here we will fold, save Print_In_Hex indication
2055 Hex
:= Nkind
(Operand
) = N_Integer_Literal
2056 and then Print_In_Hex
(Operand
);
2058 -- Fold the result of qualification
2060 if Is_Discrete_Type
(Target_Type
) then
2061 Fold_Uint
(N
, Expr_Value
(Operand
), Stat
);
2063 -- Preserve Print_In_Hex indication
2065 if Hex
and then Nkind
(N
) = N_Integer_Literal
then
2066 Set_Print_In_Hex
(N
);
2069 elsif Is_Real_Type
(Target_Type
) then
2070 Fold_Ureal
(N
, Expr_Value_R
(Operand
), Stat
);
2073 Fold_Str
(N
, Strval
(Get_String_Val
(Operand
)), Stat
);
2076 Set_Is_Static_Expression
(N
, False);
2078 Check_String_Literal_Length
(N
, Target_Type
);
2084 -- The expression may be foldable but not static
2086 Set_Is_Static_Expression
(N
, Stat
);
2088 if Is_Out_Of_Range
(N
, Etype
(N
)) then
2091 end Eval_Qualified_Expression
;
2093 -----------------------
2094 -- Eval_Real_Literal --
2095 -----------------------
2097 -- Numeric literals are static (RM 4.9(1)), and have already been marked
2098 -- as static by the analyzer. The reason we did it that early is to allow
2099 -- the possibility of turning off the Is_Static_Expression flag after
2100 -- analysis, but before resolution, when integer literals are generated
2101 -- in the expander that do not correspond to static expressions.
2103 procedure Eval_Real_Literal
(N
: Node_Id
) is
2105 -- If the literal appears in a non-expression context, then it is
2106 -- certainly appearing in a non-static context, so check it.
2108 if Nkind
(Parent
(N
)) not in N_Subexpr
then
2109 Check_Non_Static_Context
(N
);
2112 end Eval_Real_Literal
;
2114 ------------------------
2115 -- Eval_Relational_Op --
2116 ------------------------
2118 -- Relational operations are static functions, so the result is static
2119 -- if both operands are static (RM 4.9(7), 4.9(20)).
2121 procedure Eval_Relational_Op
(N
: Node_Id
) is
2122 Left
: constant Node_Id
:= Left_Opnd
(N
);
2123 Right
: constant Node_Id
:= Right_Opnd
(N
);
2124 Typ
: constant Entity_Id
:= Etype
(Left
);
2130 -- One special case to deal with first. If we can tell that
2131 -- the result will be false because the lengths of one or
2132 -- more index subtypes are compile time known and different,
2133 -- then we can replace the entire result by False. We only
2134 -- do this for one dimensional arrays, because the case of
2135 -- multi-dimensional arrays is rare and too much trouble!
2137 if Is_Array_Type
(Typ
)
2138 and then Number_Dimensions
(Typ
) = 1
2139 and then (Nkind
(N
) = N_Op_Eq
2140 or else Nkind
(N
) = N_Op_Ne
)
2142 if Raises_Constraint_Error
(Left
)
2143 or else Raises_Constraint_Error
(Right
)
2149 procedure Get_Static_Length
(Op
: Node_Id
; Len
: out Uint
);
2150 -- If Op is an expression for a constrained array with a
2151 -- known at compile time length, then Len is set to this
2152 -- (non-negative length). Otherwise Len is set to minus 1.
2154 -----------------------
2155 -- Get_Static_Length --
2156 -----------------------
2158 procedure Get_Static_Length
(Op
: Node_Id
; Len
: out Uint
) is
2162 if Nkind
(Op
) = N_String_Literal
then
2163 Len
:= UI_From_Int
(String_Length
(Strval
(Op
)));
2165 elsif not Is_Constrained
(Etype
(Op
)) then
2166 Len
:= Uint_Minus_1
;
2169 T
:= Etype
(First_Index
(Etype
(Op
)));
2171 if Is_Discrete_Type
(T
)
2173 Compile_Time_Known_Value
(Type_Low_Bound
(T
))
2175 Compile_Time_Known_Value
(Type_High_Bound
(T
))
2177 Len
:= UI_Max
(Uint_0
,
2178 Expr_Value
(Type_High_Bound
(T
)) -
2179 Expr_Value
(Type_Low_Bound
(T
)) + 1);
2181 Len
:= Uint_Minus_1
;
2184 end Get_Static_Length
;
2190 Get_Static_Length
(Left
, Len_L
);
2191 Get_Static_Length
(Right
, Len_R
);
2193 if Len_L
/= Uint_Minus_1
2194 and then Len_R
/= Uint_Minus_1
2195 and then Len_L
/= Len_R
2197 Fold_Uint
(N
, Test
(Nkind
(N
) = N_Op_Ne
), False);
2198 Warn_On_Known_Condition
(N
);
2203 -- Another special case: comparisons against null for pointers that
2204 -- are known to be non-null. This is useful when migrating from Ada95
2205 -- code when non-null restrictions are added to type declarations and
2206 -- parameter specifications.
2208 elsif Is_Access_Type
(Typ
)
2209 and then Comes_From_Source
(N
)
2211 ((Is_Entity_Name
(Left
)
2212 and then Is_Known_Non_Null
(Entity
(Left
))
2213 and then Nkind
(Right
) = N_Null
)
2215 (Is_Entity_Name
(Right
)
2216 and then Is_Known_Non_Null
(Entity
(Right
))
2217 and then Nkind
(Left
) = N_Null
))
2219 Fold_Uint
(N
, Test
(Nkind
(N
) = N_Op_Ne
), False);
2220 Warn_On_Known_Condition
(N
);
2224 -- Can only fold if type is scalar (don't fold string ops)
2226 if not Is_Scalar_Type
(Typ
) then
2227 Check_Non_Static_Context
(Left
);
2228 Check_Non_Static_Context
(Right
);
2232 -- If not foldable we are done
2234 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
2240 -- Integer and Enumeration (discrete) type cases
2242 if Is_Discrete_Type
(Typ
) then
2244 Left_Int
: constant Uint
:= Expr_Value
(Left
);
2245 Right_Int
: constant Uint
:= Expr_Value
(Right
);
2249 when N_Op_Eq
=> Result
:= Left_Int
= Right_Int
;
2250 when N_Op_Ne
=> Result
:= Left_Int
/= Right_Int
;
2251 when N_Op_Lt
=> Result
:= Left_Int
< Right_Int
;
2252 when N_Op_Le
=> Result
:= Left_Int
<= Right_Int
;
2253 when N_Op_Gt
=> Result
:= Left_Int
> Right_Int
;
2254 when N_Op_Ge
=> Result
:= Left_Int
>= Right_Int
;
2257 raise Program_Error
;
2260 Fold_Uint
(N
, Test
(Result
), Stat
);
2266 pragma Assert
(Is_Real_Type
(Typ
));
2269 Left_Real
: constant Ureal
:= Expr_Value_R
(Left
);
2270 Right_Real
: constant Ureal
:= Expr_Value_R
(Right
);
2274 when N_Op_Eq
=> Result
:= (Left_Real
= Right_Real
);
2275 when N_Op_Ne
=> Result
:= (Left_Real
/= Right_Real
);
2276 when N_Op_Lt
=> Result
:= (Left_Real
< Right_Real
);
2277 when N_Op_Le
=> Result
:= (Left_Real
<= Right_Real
);
2278 when N_Op_Gt
=> Result
:= (Left_Real
> Right_Real
);
2279 when N_Op_Ge
=> Result
:= (Left_Real
>= Right_Real
);
2282 raise Program_Error
;
2285 Fold_Uint
(N
, Test
(Result
), Stat
);
2289 Warn_On_Known_Condition
(N
);
2290 end Eval_Relational_Op
;
2296 -- Shift operations are intrinsic operations that can never be static,
2297 -- so the only processing required is to perform the required check for
2298 -- a non static context for the two operands.
2300 -- Actually we could do some compile time evaluation here some time ???
2302 procedure Eval_Shift
(N
: Node_Id
) is
2304 Check_Non_Static_Context
(Left_Opnd
(N
));
2305 Check_Non_Static_Context
(Right_Opnd
(N
));
2308 ------------------------
2309 -- Eval_Short_Circuit --
2310 ------------------------
2312 -- A short circuit operation is potentially static if both operands
2313 -- are potentially static (RM 4.9 (13))
2315 procedure Eval_Short_Circuit
(N
: Node_Id
) is
2316 Kind
: constant Node_Kind
:= Nkind
(N
);
2317 Left
: constant Node_Id
:= Left_Opnd
(N
);
2318 Right
: constant Node_Id
:= Right_Opnd
(N
);
2320 Rstat
: constant Boolean :=
2321 Is_Static_Expression
(Left
)
2322 and then Is_Static_Expression
(Right
);
2325 -- Short circuit operations are never static in Ada 83
2327 if Ada_Version
= Ada_83
2328 and then Comes_From_Source
(N
)
2330 Check_Non_Static_Context
(Left
);
2331 Check_Non_Static_Context
(Right
);
2335 -- Now look at the operands, we can't quite use the normal call to
2336 -- Test_Expression_Is_Foldable here because short circuit operations
2337 -- are a special case, they can still be foldable, even if the right
2338 -- operand raises constraint error.
2340 -- If either operand is Any_Type, just propagate to result and
2341 -- do not try to fold, this prevents cascaded errors.
2343 if Etype
(Left
) = Any_Type
or else Etype
(Right
) = Any_Type
then
2344 Set_Etype
(N
, Any_Type
);
2347 -- If left operand raises constraint error, then replace node N with
2348 -- the raise constraint error node, and we are obviously not foldable.
2349 -- Is_Static_Expression is set from the two operands in the normal way,
2350 -- and we check the right operand if it is in a non-static context.
2352 elsif Raises_Constraint_Error
(Left
) then
2354 Check_Non_Static_Context
(Right
);
2357 Rewrite_In_Raise_CE
(N
, Left
);
2358 Set_Is_Static_Expression
(N
, Rstat
);
2361 -- If the result is not static, then we won't in any case fold
2363 elsif not Rstat
then
2364 Check_Non_Static_Context
(Left
);
2365 Check_Non_Static_Context
(Right
);
2369 -- Here the result is static, note that, unlike the normal processing
2370 -- in Test_Expression_Is_Foldable, we did *not* check above to see if
2371 -- the right operand raises constraint error, that's because it is not
2372 -- significant if the left operand is decisive.
2374 Set_Is_Static_Expression
(N
);
2376 -- It does not matter if the right operand raises constraint error if
2377 -- it will not be evaluated. So deal specially with the cases where
2378 -- the right operand is not evaluated. Note that we will fold these
2379 -- cases even if the right operand is non-static, which is fine, but
2380 -- of course in these cases the result is not potentially static.
2382 Left_Int
:= Expr_Value
(Left
);
2384 if (Kind
= N_And_Then
and then Is_False
(Left_Int
))
2385 or else (Kind
= N_Or_Else
and Is_True
(Left_Int
))
2387 Fold_Uint
(N
, Left_Int
, Rstat
);
2391 -- If first operand not decisive, then it does matter if the right
2392 -- operand raises constraint error, since it will be evaluated, so
2393 -- we simply replace the node with the right operand. Note that this
2394 -- properly propagates Is_Static_Expression and Raises_Constraint_Error
2395 -- (both are set to True in Right).
2397 if Raises_Constraint_Error
(Right
) then
2398 Rewrite_In_Raise_CE
(N
, Right
);
2399 Check_Non_Static_Context
(Left
);
2403 -- Otherwise the result depends on the right operand
2405 Fold_Uint
(N
, Expr_Value
(Right
), Rstat
);
2407 end Eval_Short_Circuit
;
2413 -- Slices can never be static, so the only processing required is to
2414 -- check for non-static context if an explicit range is given.
2416 procedure Eval_Slice
(N
: Node_Id
) is
2417 Drange
: constant Node_Id
:= Discrete_Range
(N
);
2420 if Nkind
(Drange
) = N_Range
then
2421 Check_Non_Static_Context
(Low_Bound
(Drange
));
2422 Check_Non_Static_Context
(High_Bound
(Drange
));
2426 -------------------------
2427 -- Eval_String_Literal --
2428 -------------------------
2430 procedure Eval_String_Literal
(N
: Node_Id
) is
2431 Typ
: constant Entity_Id
:= Etype
(N
);
2432 Bas
: constant Entity_Id
:= Base_Type
(Typ
);
2438 -- Nothing to do if error type (handles cases like default expressions
2439 -- or generics where we have not yet fully resolved the type)
2441 if Bas
= Any_Type
or else Bas
= Any_String
then
2445 -- String literals are static if the subtype is static (RM 4.9(2)), so
2446 -- reset the static expression flag (it was set unconditionally in
2447 -- Analyze_String_Literal) if the subtype is non-static. We tell if
2448 -- the subtype is static by looking at the lower bound.
2450 if Ekind
(Typ
) = E_String_Literal_Subtype
then
2451 if not Is_OK_Static_Expression
(String_Literal_Low_Bound
(Typ
)) then
2452 Set_Is_Static_Expression
(N
, False);
2456 -- Here if Etype of string literal is normal Etype (not yet possible,
2457 -- but may be possible in future!)
2459 elsif not Is_OK_Static_Expression
2460 (Type_Low_Bound
(Etype
(First_Index
(Typ
))))
2462 Set_Is_Static_Expression
(N
, False);
2466 -- If original node was a type conversion, then result if non-static
2468 if Nkind
(Original_Node
(N
)) = N_Type_Conversion
then
2469 Set_Is_Static_Expression
(N
, False);
2473 -- Test for illegal Ada 95 cases. A string literal is illegal in
2474 -- Ada 95 if its bounds are outside the index base type and this
2475 -- index type is static. This can happen in only two ways. Either
2476 -- the string literal is too long, or it is null, and the lower
2477 -- bound is type'First. In either case it is the upper bound that
2478 -- is out of range of the index type.
2480 if Ada_Version
>= Ada_95
then
2481 if Root_Type
(Bas
) = Standard_String
2483 Root_Type
(Bas
) = Standard_Wide_String
2485 Xtp
:= Standard_Positive
;
2487 Xtp
:= Etype
(First_Index
(Bas
));
2490 if Ekind
(Typ
) = E_String_Literal_Subtype
then
2491 Lo
:= String_Literal_Low_Bound
(Typ
);
2493 Lo
:= Type_Low_Bound
(Etype
(First_Index
(Typ
)));
2496 Len
:= String_Length
(Strval
(N
));
2498 if UI_From_Int
(Len
) > String_Type_Len
(Bas
) then
2499 Apply_Compile_Time_Constraint_Error
2500 (N
, "string literal too long for}", CE_Length_Check_Failed
,
2502 Typ
=> First_Subtype
(Bas
));
2505 and then not Is_Generic_Type
(Xtp
)
2507 Expr_Value
(Lo
) = Expr_Value
(Type_Low_Bound
(Base_Type
(Xtp
)))
2509 Apply_Compile_Time_Constraint_Error
2510 (N
, "null string literal not allowed for}",
2511 CE_Length_Check_Failed
,
2513 Typ
=> First_Subtype
(Bas
));
2516 end Eval_String_Literal
;
2518 --------------------------
2519 -- Eval_Type_Conversion --
2520 --------------------------
2522 -- A type conversion is potentially static if its subtype mark is for a
2523 -- static scalar subtype, and its operand expression is potentially static
2526 procedure Eval_Type_Conversion
(N
: Node_Id
) is
2527 Operand
: constant Node_Id
:= Expression
(N
);
2528 Source_Type
: constant Entity_Id
:= Etype
(Operand
);
2529 Target_Type
: constant Entity_Id
:= Etype
(N
);
2534 function To_Be_Treated_As_Integer
(T
: Entity_Id
) return Boolean;
2535 -- Returns true if type T is an integer type, or if it is a
2536 -- fixed-point type to be treated as an integer (i.e. the flag
2537 -- Conversion_OK is set on the conversion node).
2539 function To_Be_Treated_As_Real
(T
: Entity_Id
) return Boolean;
2540 -- Returns true if type T is a floating-point type, or if it is a
2541 -- fixed-point type that is not to be treated as an integer (i.e. the
2542 -- flag Conversion_OK is not set on the conversion node).
2544 ------------------------------
2545 -- To_Be_Treated_As_Integer --
2546 ------------------------------
2548 function To_Be_Treated_As_Integer
(T
: Entity_Id
) return Boolean is
2552 or else (Is_Fixed_Point_Type
(T
) and then Conversion_OK
(N
));
2553 end To_Be_Treated_As_Integer
;
2555 ---------------------------
2556 -- To_Be_Treated_As_Real --
2557 ---------------------------
2559 function To_Be_Treated_As_Real
(T
: Entity_Id
) return Boolean is
2562 Is_Floating_Point_Type
(T
)
2563 or else (Is_Fixed_Point_Type
(T
) and then not Conversion_OK
(N
));
2564 end To_Be_Treated_As_Real
;
2566 -- Start of processing for Eval_Type_Conversion
2569 -- Cannot fold if target type is non-static or if semantic error
2571 if not Is_Static_Subtype
(Target_Type
) then
2572 Check_Non_Static_Context
(Operand
);
2575 elsif Error_Posted
(N
) then
2579 -- If not foldable we are done
2581 Test_Expression_Is_Foldable
(N
, Operand
, Stat
, Fold
);
2586 -- Don't try fold if target type has constraint error bounds
2588 elsif not Is_OK_Static_Subtype
(Target_Type
) then
2589 Set_Raises_Constraint_Error
(N
);
2593 -- Remaining processing depends on operand types. Note that in the
2594 -- following type test, fixed-point counts as real unless the flag
2595 -- Conversion_OK is set, in which case it counts as integer.
2597 -- Fold conversion, case of string type. The result is not static
2599 if Is_String_Type
(Target_Type
) then
2600 Fold_Str
(N
, Strval
(Get_String_Val
(Operand
)), False);
2604 -- Fold conversion, case of integer target type
2606 elsif To_Be_Treated_As_Integer
(Target_Type
) then
2611 -- Integer to integer conversion
2613 if To_Be_Treated_As_Integer
(Source_Type
) then
2614 Result
:= Expr_Value
(Operand
);
2616 -- Real to integer conversion
2619 Result
:= UR_To_Uint
(Expr_Value_R
(Operand
));
2622 -- If fixed-point type (Conversion_OK must be set), then the
2623 -- result is logically an integer, but we must replace the
2624 -- conversion with the corresponding real literal, since the
2625 -- type from a semantic point of view is still fixed-point.
2627 if Is_Fixed_Point_Type
(Target_Type
) then
2629 (N
, UR_From_Uint
(Result
) * Small_Value
(Target_Type
), Stat
);
2631 -- Otherwise result is integer literal
2634 Fold_Uint
(N
, Result
, Stat
);
2638 -- Fold conversion, case of real target type
2640 elsif To_Be_Treated_As_Real
(Target_Type
) then
2645 if To_Be_Treated_As_Real
(Source_Type
) then
2646 Result
:= Expr_Value_R
(Operand
);
2648 Result
:= UR_From_Uint
(Expr_Value
(Operand
));
2651 Fold_Ureal
(N
, Result
, Stat
);
2654 -- Enumeration types
2657 Fold_Uint
(N
, Expr_Value
(Operand
), Stat
);
2660 if Is_Out_Of_Range
(N
, Etype
(N
)) then
2664 end Eval_Type_Conversion
;
2670 -- Predefined unary operators are static functions (RM 4.9(20)) and thus
2671 -- are potentially static if the operand is potentially static (RM 4.9(7))
2673 procedure Eval_Unary_Op
(N
: Node_Id
) is
2674 Right
: constant Node_Id
:= Right_Opnd
(N
);
2679 -- If not foldable we are done
2681 Test_Expression_Is_Foldable
(N
, Right
, Stat
, Fold
);
2687 -- Fold for integer case
2689 if Is_Integer_Type
(Etype
(N
)) then
2691 Rint
: constant Uint
:= Expr_Value
(Right
);
2695 -- In the case of modular unary plus and abs there is no need
2696 -- to adjust the result of the operation since if the original
2697 -- operand was in bounds the result will be in the bounds of the
2698 -- modular type. However, in the case of modular unary minus the
2699 -- result may go out of the bounds of the modular type and needs
2702 if Nkind
(N
) = N_Op_Plus
then
2705 elsif Nkind
(N
) = N_Op_Minus
then
2706 if Is_Modular_Integer_Type
(Etype
(N
)) then
2707 Result
:= (-Rint
) mod Modulus
(Etype
(N
));
2713 pragma Assert
(Nkind
(N
) = N_Op_Abs
);
2717 Fold_Uint
(N
, Result
, Stat
);
2720 -- Fold for real case
2722 elsif Is_Real_Type
(Etype
(N
)) then
2724 Rreal
: constant Ureal
:= Expr_Value_R
(Right
);
2728 if Nkind
(N
) = N_Op_Plus
then
2731 elsif Nkind
(N
) = N_Op_Minus
then
2732 Result
:= UR_Negate
(Rreal
);
2735 pragma Assert
(Nkind
(N
) = N_Op_Abs
);
2736 Result
:= abs Rreal
;
2739 Fold_Ureal
(N
, Result
, Stat
);
2744 -------------------------------
2745 -- Eval_Unchecked_Conversion --
2746 -------------------------------
2748 -- Unchecked conversions can never be static, so the only required
2749 -- processing is to check for a non-static context for the operand.
2751 procedure Eval_Unchecked_Conversion
(N
: Node_Id
) is
2753 Check_Non_Static_Context
(Expression
(N
));
2754 end Eval_Unchecked_Conversion
;
2756 --------------------
2757 -- Expr_Rep_Value --
2758 --------------------
2760 function Expr_Rep_Value
(N
: Node_Id
) return Uint
is
2761 Kind
: constant Node_Kind
:= Nkind
(N
);
2765 if Is_Entity_Name
(N
) then
2768 -- An enumeration literal that was either in the source or
2769 -- created as a result of static evaluation.
2771 if Ekind
(Ent
) = E_Enumeration_Literal
then
2772 return Enumeration_Rep
(Ent
);
2774 -- A user defined static constant
2777 pragma Assert
(Ekind
(Ent
) = E_Constant
);
2778 return Expr_Rep_Value
(Constant_Value
(Ent
));
2781 -- An integer literal that was either in the source or created
2782 -- as a result of static evaluation.
2784 elsif Kind
= N_Integer_Literal
then
2787 -- A real literal for a fixed-point type. This must be the fixed-point
2788 -- case, either the literal is of a fixed-point type, or it is a bound
2789 -- of a fixed-point type, with type universal real. In either case we
2790 -- obtain the desired value from Corresponding_Integer_Value.
2792 elsif Kind
= N_Real_Literal
then
2793 pragma Assert
(Is_Fixed_Point_Type
(Underlying_Type
(Etype
(N
))));
2794 return Corresponding_Integer_Value
(N
);
2796 -- Peculiar VMS case, if we have xxx'Null_Parameter, return zero
2798 elsif Kind
= N_Attribute_Reference
2799 and then Attribute_Name
(N
) = Name_Null_Parameter
2803 -- Otherwise must be character literal
2806 pragma Assert
(Kind
= N_Character_Literal
);
2809 -- Since Character literals of type Standard.Character don't
2810 -- have any defining character literals built for them, they
2811 -- do not have their Entity set, so just use their Char
2812 -- code. Otherwise for user-defined character literals use
2813 -- their Pos value as usual which is the same as the Rep value.
2816 return Char_Literal_Value
(N
);
2818 return Enumeration_Rep
(Ent
);
2827 function Expr_Value
(N
: Node_Id
) return Uint
is
2828 Kind
: constant Node_Kind
:= Nkind
(N
);
2829 CV_Ent
: CV_Entry
renames CV_Cache
(Nat
(N
) mod CV_Cache_Size
);
2834 -- If already in cache, then we know it's compile time known and
2835 -- we can return the value that was previously stored in the cache
2836 -- since compile time known values cannot change :-)
2838 if CV_Ent
.N
= N
then
2842 -- Otherwise proceed to test value
2844 if Is_Entity_Name
(N
) then
2847 -- An enumeration literal that was either in the source or
2848 -- created as a result of static evaluation.
2850 if Ekind
(Ent
) = E_Enumeration_Literal
then
2851 Val
:= Enumeration_Pos
(Ent
);
2853 -- A user defined static constant
2856 pragma Assert
(Ekind
(Ent
) = E_Constant
);
2857 Val
:= Expr_Value
(Constant_Value
(Ent
));
2860 -- An integer literal that was either in the source or created
2861 -- as a result of static evaluation.
2863 elsif Kind
= N_Integer_Literal
then
2866 -- A real literal for a fixed-point type. This must be the fixed-point
2867 -- case, either the literal is of a fixed-point type, or it is a bound
2868 -- of a fixed-point type, with type universal real. In either case we
2869 -- obtain the desired value from Corresponding_Integer_Value.
2871 elsif Kind
= N_Real_Literal
then
2873 pragma Assert
(Is_Fixed_Point_Type
(Underlying_Type
(Etype
(N
))));
2874 Val
:= Corresponding_Integer_Value
(N
);
2876 -- Peculiar VMS case, if we have xxx'Null_Parameter, return zero
2878 elsif Kind
= N_Attribute_Reference
2879 and then Attribute_Name
(N
) = Name_Null_Parameter
2883 -- Otherwise must be character literal
2886 pragma Assert
(Kind
= N_Character_Literal
);
2889 -- Since Character literals of type Standard.Character don't
2890 -- have any defining character literals built for them, they
2891 -- do not have their Entity set, so just use their Char
2892 -- code. Otherwise for user-defined character literals use
2893 -- their Pos value as usual.
2896 Val
:= Char_Literal_Value
(N
);
2898 Val
:= Enumeration_Pos
(Ent
);
2902 -- Come here with Val set to value to be returned, set cache
2913 function Expr_Value_E
(N
: Node_Id
) return Entity_Id
is
2914 Ent
: constant Entity_Id
:= Entity
(N
);
2917 if Ekind
(Ent
) = E_Enumeration_Literal
then
2920 pragma Assert
(Ekind
(Ent
) = E_Constant
);
2921 return Expr_Value_E
(Constant_Value
(Ent
));
2929 function Expr_Value_R
(N
: Node_Id
) return Ureal
is
2930 Kind
: constant Node_Kind
:= Nkind
(N
);
2935 if Kind
= N_Real_Literal
then
2938 elsif Kind
= N_Identifier
or else Kind
= N_Expanded_Name
then
2940 pragma Assert
(Ekind
(Ent
) = E_Constant
);
2941 return Expr_Value_R
(Constant_Value
(Ent
));
2943 elsif Kind
= N_Integer_Literal
then
2944 return UR_From_Uint
(Expr_Value
(N
));
2946 -- Strange case of VAX literals, which are at this stage transformed
2947 -- into Vax_Type!x_To_y(IEEE_Literal). See Expand_N_Real_Literal in
2948 -- Exp_Vfpt for further details.
2950 elsif Vax_Float
(Etype
(N
))
2951 and then Nkind
(N
) = N_Unchecked_Type_Conversion
2953 Expr
:= Expression
(N
);
2955 if Nkind
(Expr
) = N_Function_Call
2956 and then Present
(Parameter_Associations
(Expr
))
2958 Expr
:= First
(Parameter_Associations
(Expr
));
2960 if Nkind
(Expr
) = N_Real_Literal
then
2961 return Realval
(Expr
);
2965 -- Peculiar VMS case, if we have xxx'Null_Parameter, return 0.0
2967 elsif Kind
= N_Attribute_Reference
2968 and then Attribute_Name
(N
) = Name_Null_Parameter
2973 -- If we fall through, we have a node that cannot be interepreted
2974 -- as a compile time constant. That is definitely an error.
2976 raise Program_Error
;
2983 function Expr_Value_S
(N
: Node_Id
) return Node_Id
is
2985 if Nkind
(N
) = N_String_Literal
then
2988 pragma Assert
(Ekind
(Entity
(N
)) = E_Constant
);
2989 return Expr_Value_S
(Constant_Value
(Entity
(N
)));
2993 --------------------------
2994 -- Flag_Non_Static_Expr --
2995 --------------------------
2997 procedure Flag_Non_Static_Expr
(Msg
: String; Expr
: Node_Id
) is
2999 if Error_Posted
(Expr
) and then not All_Errors_Mode
then
3002 Error_Msg_F
(Msg
, Expr
);
3003 Why_Not_Static
(Expr
);
3005 end Flag_Non_Static_Expr
;
3011 procedure Fold_Str
(N
: Node_Id
; Val
: String_Id
; Static
: Boolean) is
3012 Loc
: constant Source_Ptr
:= Sloc
(N
);
3013 Typ
: constant Entity_Id
:= Etype
(N
);
3016 Rewrite
(N
, Make_String_Literal
(Loc
, Strval
=> Val
));
3018 -- We now have the literal with the right value, both the actual type
3019 -- and the expected type of this literal are taken from the expression
3020 -- that was evaluated.
3023 Set_Is_Static_Expression
(N
, Static
);
3032 procedure Fold_Uint
(N
: Node_Id
; Val
: Uint
; Static
: Boolean) is
3033 Loc
: constant Source_Ptr
:= Sloc
(N
);
3034 Typ
: Entity_Id
:= Etype
(N
);
3038 -- If we are folding a named number, retain the entity in the
3039 -- literal, for ASIS use.
3041 if Is_Entity_Name
(N
)
3042 and then Ekind
(Entity
(N
)) = E_Named_Integer
3049 if Is_Private_Type
(Typ
) then
3050 Typ
:= Full_View
(Typ
);
3053 -- For a result of type integer, subsitute an N_Integer_Literal node
3054 -- for the result of the compile time evaluation of the expression.
3056 if Is_Integer_Type
(Typ
) then
3057 Rewrite
(N
, Make_Integer_Literal
(Loc
, Val
));
3058 Set_Original_Entity
(N
, Ent
);
3060 -- Otherwise we have an enumeration type, and we substitute either
3061 -- an N_Identifier or N_Character_Literal to represent the enumeration
3062 -- literal corresponding to the given value, which must always be in
3063 -- range, because appropriate tests have already been made for this.
3065 else pragma Assert
(Is_Enumeration_Type
(Typ
));
3066 Rewrite
(N
, Get_Enum_Lit_From_Pos
(Etype
(N
), Val
, Loc
));
3069 -- We now have the literal with the right value, both the actual type
3070 -- and the expected type of this literal are taken from the expression
3071 -- that was evaluated.
3074 Set_Is_Static_Expression
(N
, Static
);
3083 procedure Fold_Ureal
(N
: Node_Id
; Val
: Ureal
; Static
: Boolean) is
3084 Loc
: constant Source_Ptr
:= Sloc
(N
);
3085 Typ
: constant Entity_Id
:= Etype
(N
);
3089 -- If we are folding a named number, retain the entity in the
3090 -- literal, for ASIS use.
3092 if Is_Entity_Name
(N
)
3093 and then Ekind
(Entity
(N
)) = E_Named_Real
3100 Rewrite
(N
, Make_Real_Literal
(Loc
, Realval
=> Val
));
3101 Set_Original_Entity
(N
, Ent
);
3103 -- Both the actual and expected type comes from the original expression
3106 Set_Is_Static_Expression
(N
, Static
);
3115 function From_Bits
(B
: Bits
; T
: Entity_Id
) return Uint
is
3119 for J
in 0 .. B
'Last loop
3125 if Non_Binary_Modulus
(T
) then
3126 V
:= V
mod Modulus
(T
);
3132 --------------------
3133 -- Get_String_Val --
3134 --------------------
3136 function Get_String_Val
(N
: Node_Id
) return Node_Id
is
3138 if Nkind
(N
) = N_String_Literal
then
3141 elsif Nkind
(N
) = N_Character_Literal
then
3145 pragma Assert
(Is_Entity_Name
(N
));
3146 return Get_String_Val
(Constant_Value
(Entity
(N
)));
3154 procedure Initialize
is
3156 CV_Cache
:= (others => (Node_High_Bound
, Uint_0
));
3159 --------------------
3160 -- In_Subrange_Of --
3161 --------------------
3163 function In_Subrange_Of
3166 Fixed_Int
: Boolean := False) return Boolean
3175 if T1
= T2
or else Is_Subtype_Of
(T1
, T2
) then
3178 -- Never in range if both types are not scalar. Don't know if this can
3179 -- actually happen, but just in case.
3181 elsif not Is_Scalar_Type
(T1
) or else not Is_Scalar_Type
(T1
) then
3185 L1
:= Type_Low_Bound
(T1
);
3186 H1
:= Type_High_Bound
(T1
);
3188 L2
:= Type_Low_Bound
(T2
);
3189 H2
:= Type_High_Bound
(T2
);
3191 -- Check bounds to see if comparison possible at compile time
3193 if Compile_Time_Compare
(L1
, L2
) in Compare_GE
3195 Compile_Time_Compare
(H1
, H2
) in Compare_LE
3200 -- If bounds not comparable at compile time, then the bounds of T2
3201 -- must be compile time known or we cannot answer the query.
3203 if not Compile_Time_Known_Value
(L2
)
3204 or else not Compile_Time_Known_Value
(H2
)
3209 -- If the bounds of T1 are know at compile time then use these
3210 -- ones, otherwise use the bounds of the base type (which are of
3211 -- course always static).
3213 if not Compile_Time_Known_Value
(L1
) then
3214 L1
:= Type_Low_Bound
(Base_Type
(T1
));
3217 if not Compile_Time_Known_Value
(H1
) then
3218 H1
:= Type_High_Bound
(Base_Type
(T1
));
3221 -- Fixed point types should be considered as such only if
3222 -- flag Fixed_Int is set to False.
3224 if Is_Floating_Point_Type
(T1
) or else Is_Floating_Point_Type
(T2
)
3225 or else (Is_Fixed_Point_Type
(T1
) and then not Fixed_Int
)
3226 or else (Is_Fixed_Point_Type
(T2
) and then not Fixed_Int
)
3229 Expr_Value_R
(L2
) <= Expr_Value_R
(L1
)
3231 Expr_Value_R
(H2
) >= Expr_Value_R
(H1
);
3235 Expr_Value
(L2
) <= Expr_Value
(L1
)
3237 Expr_Value
(H2
) >= Expr_Value
(H1
);
3242 -- If any exception occurs, it means that we have some bug in the compiler
3243 -- possibly triggered by a previous error, or by some unforseen peculiar
3244 -- occurrence. However, this is only an optimization attempt, so there is
3245 -- really no point in crashing the compiler. Instead we just decide, too
3246 -- bad, we can't figure out the answer in this case after all.
3251 -- Debug flag K disables this behavior (useful for debugging)
3253 if Debug_Flag_K
then
3264 function Is_In_Range
3267 Fixed_Int
: Boolean := False;
3268 Int_Real
: Boolean := False) return Boolean
3274 -- Universal types have no range limits, so always in range
3276 if Typ
= Universal_Integer
or else Typ
= Universal_Real
then
3279 -- Never in range if not scalar type. Don't know if this can
3280 -- actually happen, but our spec allows it, so we must check!
3282 elsif not Is_Scalar_Type
(Typ
) then
3285 -- Never in range unless we have a compile time known value
3287 elsif not Compile_Time_Known_Value
(N
) then
3292 Lo
: constant Node_Id
:= Type_Low_Bound
(Typ
);
3293 Hi
: constant Node_Id
:= Type_High_Bound
(Typ
);
3294 LB_Known
: constant Boolean := Compile_Time_Known_Value
(Lo
);
3295 UB_Known
: constant Boolean := Compile_Time_Known_Value
(Hi
);
3298 -- Fixed point types should be considered as such only in
3299 -- flag Fixed_Int is set to False.
3301 if Is_Floating_Point_Type
(Typ
)
3302 or else (Is_Fixed_Point_Type
(Typ
) and then not Fixed_Int
)
3305 Valr
:= Expr_Value_R
(N
);
3307 if LB_Known
and then Valr
>= Expr_Value_R
(Lo
)
3308 and then UB_Known
and then Valr
<= Expr_Value_R
(Hi
)
3316 Val
:= Expr_Value
(N
);
3318 if LB_Known
and then Val
>= Expr_Value
(Lo
)
3319 and then UB_Known
and then Val
<= Expr_Value
(Hi
)
3334 function Is_Null_Range
(Lo
: Node_Id
; Hi
: Node_Id
) return Boolean is
3335 Typ
: constant Entity_Id
:= Etype
(Lo
);
3338 if not Compile_Time_Known_Value
(Lo
)
3339 or else not Compile_Time_Known_Value
(Hi
)
3344 if Is_Discrete_Type
(Typ
) then
3345 return Expr_Value
(Lo
) > Expr_Value
(Hi
);
3348 pragma Assert
(Is_Real_Type
(Typ
));
3349 return Expr_Value_R
(Lo
) > Expr_Value_R
(Hi
);
3353 -----------------------------
3354 -- Is_OK_Static_Expression --
3355 -----------------------------
3357 function Is_OK_Static_Expression
(N
: Node_Id
) return Boolean is
3359 return Is_Static_Expression
(N
)
3360 and then not Raises_Constraint_Error
(N
);
3361 end Is_OK_Static_Expression
;
3363 ------------------------
3364 -- Is_OK_Static_Range --
3365 ------------------------
3367 -- A static range is a range whose bounds are static expressions, or a
3368 -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)).
3369 -- We have already converted range attribute references, so we get the
3370 -- "or" part of this rule without needing a special test.
3372 function Is_OK_Static_Range
(N
: Node_Id
) return Boolean is
3374 return Is_OK_Static_Expression
(Low_Bound
(N
))
3375 and then Is_OK_Static_Expression
(High_Bound
(N
));
3376 end Is_OK_Static_Range
;
3378 --------------------------
3379 -- Is_OK_Static_Subtype --
3380 --------------------------
3382 -- Determines if Typ is a static subtype as defined in (RM 4.9(26))
3383 -- where neither bound raises constraint error when evaluated.
3385 function Is_OK_Static_Subtype
(Typ
: Entity_Id
) return Boolean is
3386 Base_T
: constant Entity_Id
:= Base_Type
(Typ
);
3387 Anc_Subt
: Entity_Id
;
3390 -- First a quick check on the non static subtype flag. As described
3391 -- in further detail in Einfo, this flag is not decisive in all cases,
3392 -- but if it is set, then the subtype is definitely non-static.
3394 if Is_Non_Static_Subtype
(Typ
) then
3398 Anc_Subt
:= Ancestor_Subtype
(Typ
);
3400 if Anc_Subt
= Empty
then
3404 if Is_Generic_Type
(Root_Type
(Base_T
))
3405 or else Is_Generic_Actual_Type
(Base_T
)
3411 elsif Is_String_Type
(Typ
) then
3413 Ekind
(Typ
) = E_String_Literal_Subtype
3415 (Is_OK_Static_Subtype
(Component_Type
(Typ
))
3416 and then Is_OK_Static_Subtype
(Etype
(First_Index
(Typ
))));
3420 elsif Is_Scalar_Type
(Typ
) then
3421 if Base_T
= Typ
then
3425 -- Scalar_Range (Typ) might be an N_Subtype_Indication, so
3426 -- use Get_Type_Low,High_Bound.
3428 return Is_OK_Static_Subtype
(Anc_Subt
)
3429 and then Is_OK_Static_Expression
(Type_Low_Bound
(Typ
))
3430 and then Is_OK_Static_Expression
(Type_High_Bound
(Typ
));
3433 -- Types other than string and scalar types are never static
3438 end Is_OK_Static_Subtype
;
3440 ---------------------
3441 -- Is_Out_Of_Range --
3442 ---------------------
3444 function Is_Out_Of_Range
3447 Fixed_Int
: Boolean := False;
3448 Int_Real
: Boolean := False) return Boolean
3454 -- Universal types have no range limits, so always in range
3456 if Typ
= Universal_Integer
or else Typ
= Universal_Real
then
3459 -- Never out of range if not scalar type. Don't know if this can
3460 -- actually happen, but our spec allows it, so we must check!
3462 elsif not Is_Scalar_Type
(Typ
) then
3465 -- Never out of range if this is a generic type, since the bounds
3466 -- of generic types are junk. Note that if we only checked for
3467 -- static expressions (instead of compile time known values) below,
3468 -- we would not need this check, because values of a generic type
3469 -- can never be static, but they can be known at compile time.
3471 elsif Is_Generic_Type
(Typ
) then
3474 -- Never out of range unless we have a compile time known value
3476 elsif not Compile_Time_Known_Value
(N
) then
3481 Lo
: constant Node_Id
:= Type_Low_Bound
(Typ
);
3482 Hi
: constant Node_Id
:= Type_High_Bound
(Typ
);
3483 LB_Known
: constant Boolean := Compile_Time_Known_Value
(Lo
);
3484 UB_Known
: constant Boolean := Compile_Time_Known_Value
(Hi
);
3487 -- Real types (note that fixed-point types are not treated
3488 -- as being of a real type if the flag Fixed_Int is set,
3489 -- since in that case they are regarded as integer types).
3491 if Is_Floating_Point_Type
(Typ
)
3492 or else (Is_Fixed_Point_Type
(Typ
) and then not Fixed_Int
)
3495 Valr
:= Expr_Value_R
(N
);
3497 if LB_Known
and then Valr
< Expr_Value_R
(Lo
) then
3500 elsif UB_Known
and then Expr_Value_R
(Hi
) < Valr
then
3508 Val
:= Expr_Value
(N
);
3510 if LB_Known
and then Val
< Expr_Value
(Lo
) then
3513 elsif UB_Known
and then Expr_Value
(Hi
) < Val
then
3522 end Is_Out_Of_Range
;
3524 ---------------------
3525 -- Is_Static_Range --
3526 ---------------------
3528 -- A static range is a range whose bounds are static expressions, or a
3529 -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)).
3530 -- We have already converted range attribute references, so we get the
3531 -- "or" part of this rule without needing a special test.
3533 function Is_Static_Range
(N
: Node_Id
) return Boolean is
3535 return Is_Static_Expression
(Low_Bound
(N
))
3536 and then Is_Static_Expression
(High_Bound
(N
));
3537 end Is_Static_Range
;
3539 -----------------------
3540 -- Is_Static_Subtype --
3541 -----------------------
3543 -- Determines if Typ is a static subtype as defined in (RM 4.9(26))
3545 function Is_Static_Subtype
(Typ
: Entity_Id
) return Boolean is
3546 Base_T
: constant Entity_Id
:= Base_Type
(Typ
);
3547 Anc_Subt
: Entity_Id
;
3550 -- First a quick check on the non static subtype flag. As described
3551 -- in further detail in Einfo, this flag is not decisive in all cases,
3552 -- but if it is set, then the subtype is definitely non-static.
3554 if Is_Non_Static_Subtype
(Typ
) then
3558 Anc_Subt
:= Ancestor_Subtype
(Typ
);
3560 if Anc_Subt
= Empty
then
3564 if Is_Generic_Type
(Root_Type
(Base_T
))
3565 or else Is_Generic_Actual_Type
(Base_T
)
3571 elsif Is_String_Type
(Typ
) then
3573 Ekind
(Typ
) = E_String_Literal_Subtype
3575 (Is_Static_Subtype
(Component_Type
(Typ
))
3576 and then Is_Static_Subtype
(Etype
(First_Index
(Typ
))));
3580 elsif Is_Scalar_Type
(Typ
) then
3581 if Base_T
= Typ
then
3585 return Is_Static_Subtype
(Anc_Subt
)
3586 and then Is_Static_Expression
(Type_Low_Bound
(Typ
))
3587 and then Is_Static_Expression
(Type_High_Bound
(Typ
));
3590 -- Types other than string and scalar types are never static
3595 end Is_Static_Subtype
;
3597 --------------------
3598 -- Not_Null_Range --
3599 --------------------
3601 function Not_Null_Range
(Lo
: Node_Id
; Hi
: Node_Id
) return Boolean is
3602 Typ
: constant Entity_Id
:= Etype
(Lo
);
3605 if not Compile_Time_Known_Value
(Lo
)
3606 or else not Compile_Time_Known_Value
(Hi
)
3611 if Is_Discrete_Type
(Typ
) then
3612 return Expr_Value
(Lo
) <= Expr_Value
(Hi
);
3615 pragma Assert
(Is_Real_Type
(Typ
));
3617 return Expr_Value_R
(Lo
) <= Expr_Value_R
(Hi
);
3625 function OK_Bits
(N
: Node_Id
; Bits
: Uint
) return Boolean is
3627 -- We allow a maximum of 500,000 bits which seems a reasonable limit
3629 if Bits
< 500_000
then
3633 Error_Msg_N
("static value too large, capacity exceeded", N
);
3642 procedure Out_Of_Range
(N
: Node_Id
) is
3644 -- If we have the static expression case, then this is an illegality
3645 -- in Ada 95 mode, except that in an instance, we never generate an
3646 -- error (if the error is legitimate, it was already diagnosed in
3647 -- the template). The expression to compute the length of a packed
3648 -- array is attached to the array type itself, and deserves a separate
3651 if Is_Static_Expression
(N
)
3652 and then not In_Instance
3653 and then not In_Inlined_Body
3654 and then Ada_Version
>= Ada_95
3656 if Nkind
(Parent
(N
)) = N_Defining_Identifier
3657 and then Is_Array_Type
(Parent
(N
))
3658 and then Present
(Packed_Array_Type
(Parent
(N
)))
3659 and then Present
(First_Rep_Item
(Parent
(N
)))
3662 ("length of packed array must not exceed Integer''Last",
3663 First_Rep_Item
(Parent
(N
)));
3664 Rewrite
(N
, Make_Integer_Literal
(Sloc
(N
), Uint_1
));
3667 Apply_Compile_Time_Constraint_Error
3668 (N
, "value not in range of}", CE_Range_Check_Failed
);
3671 -- Here we generate a warning for the Ada 83 case, or when we are
3672 -- in an instance, or when we have a non-static expression case.
3675 Apply_Compile_Time_Constraint_Error
3676 (N
, "value not in range of}?", CE_Range_Check_Failed
);
3680 -------------------------
3681 -- Rewrite_In_Raise_CE --
3682 -------------------------
3684 procedure Rewrite_In_Raise_CE
(N
: Node_Id
; Exp
: Node_Id
) is
3685 Typ
: constant Entity_Id
:= Etype
(N
);
3688 -- If we want to raise CE in the condition of a raise_CE node
3689 -- we may as well get rid of the condition
3691 if Present
(Parent
(N
))
3692 and then Nkind
(Parent
(N
)) = N_Raise_Constraint_Error
3694 Set_Condition
(Parent
(N
), Empty
);
3696 -- If the expression raising CE is a N_Raise_CE node, we can use
3697 -- that one. We just preserve the type of the context
3699 elsif Nkind
(Exp
) = N_Raise_Constraint_Error
then
3703 -- We have to build an explicit raise_ce node
3707 Make_Raise_Constraint_Error
(Sloc
(Exp
),
3708 Reason
=> CE_Range_Check_Failed
));
3709 Set_Raises_Constraint_Error
(N
);
3712 end Rewrite_In_Raise_CE
;
3714 ---------------------
3715 -- String_Type_Len --
3716 ---------------------
3718 function String_Type_Len
(Stype
: Entity_Id
) return Uint
is
3719 NT
: constant Entity_Id
:= Etype
(First_Index
(Stype
));
3723 if Is_OK_Static_Subtype
(NT
) then
3726 T
:= Base_Type
(NT
);
3729 return Expr_Value
(Type_High_Bound
(T
)) -
3730 Expr_Value
(Type_Low_Bound
(T
)) + 1;
3731 end String_Type_Len
;
3733 ------------------------------------
3734 -- Subtypes_Statically_Compatible --
3735 ------------------------------------
3737 function Subtypes_Statically_Compatible
3739 T2
: Entity_Id
) return Boolean
3742 if Is_Scalar_Type
(T1
) then
3744 -- Definitely compatible if we match
3746 if Subtypes_Statically_Match
(T1
, T2
) then
3749 -- If either subtype is nonstatic then they're not compatible
3751 elsif not Is_Static_Subtype
(T1
)
3752 or else not Is_Static_Subtype
(T2
)
3756 -- If either type has constraint error bounds, then consider that
3757 -- they match to avoid junk cascaded errors here.
3759 elsif not Is_OK_Static_Subtype
(T1
)
3760 or else not Is_OK_Static_Subtype
(T2
)
3764 -- Base types must match, but we don't check that (should
3765 -- we???) but we do at least check that both types are
3766 -- real, or both types are not real.
3768 elsif Is_Real_Type
(T1
) /= Is_Real_Type
(T2
) then
3771 -- Here we check the bounds
3775 LB1
: constant Node_Id
:= Type_Low_Bound
(T1
);
3776 HB1
: constant Node_Id
:= Type_High_Bound
(T1
);
3777 LB2
: constant Node_Id
:= Type_Low_Bound
(T2
);
3778 HB2
: constant Node_Id
:= Type_High_Bound
(T2
);
3781 if Is_Real_Type
(T1
) then
3783 (Expr_Value_R
(LB1
) > Expr_Value_R
(HB1
))
3785 (Expr_Value_R
(LB2
) <= Expr_Value_R
(LB1
)
3787 Expr_Value_R
(HB1
) <= Expr_Value_R
(HB2
));
3791 (Expr_Value
(LB1
) > Expr_Value
(HB1
))
3793 (Expr_Value
(LB2
) <= Expr_Value
(LB1
)
3795 Expr_Value
(HB1
) <= Expr_Value
(HB2
));
3800 elsif Is_Access_Type
(T1
) then
3801 return not Is_Constrained
(T2
)
3802 or else Subtypes_Statically_Match
3803 (Designated_Type
(T1
), Designated_Type
(T2
));
3806 return (Is_Composite_Type
(T1
) and then not Is_Constrained
(T2
))
3807 or else Subtypes_Statically_Match
(T1
, T2
);
3809 end Subtypes_Statically_Compatible
;
3811 -------------------------------
3812 -- Subtypes_Statically_Match --
3813 -------------------------------
3815 -- Subtypes statically match if they have statically matching constraints
3816 -- (RM 4.9.1(2)). Constraints statically match if there are none, or if
3817 -- they are the same identical constraint, or if they are static and the
3818 -- values match (RM 4.9.1(1)).
3820 function Subtypes_Statically_Match
(T1
, T2
: Entity_Id
) return Boolean is
3822 -- A type always statically matches itself
3829 elsif Is_Scalar_Type
(T1
) then
3831 -- Base types must be the same
3833 if Base_Type
(T1
) /= Base_Type
(T2
) then
3837 -- A constrained numeric subtype never matches an unconstrained
3838 -- subtype, i.e. both types must be constrained or unconstrained.
3840 -- To understand the requirement for this test, see RM 4.9.1(1).
3841 -- As is made clear in RM 3.5.4(11), type Integer, for example
3842 -- is a constrained subtype with constraint bounds matching the
3843 -- bounds of its corresponding uncontrained base type. In this
3844 -- situation, Integer and Integer'Base do not statically match,
3845 -- even though they have the same bounds.
3847 -- We only apply this test to types in Standard and types that
3848 -- appear in user programs. That way, we do not have to be
3849 -- too careful about setting Is_Constrained right for itypes.
3851 if Is_Numeric_Type
(T1
)
3852 and then (Is_Constrained
(T1
) /= Is_Constrained
(T2
))
3853 and then (Scope
(T1
) = Standard_Standard
3854 or else Comes_From_Source
(T1
))
3855 and then (Scope
(T2
) = Standard_Standard
3856 or else Comes_From_Source
(T2
))
3860 -- A generic scalar type does not statically match its base
3861 -- type (AI-311). In this case we make sure that the formals,
3862 -- which are first subtypes of their bases, are constrained.
3864 elsif Is_Generic_Type
(T1
)
3865 and then Is_Generic_Type
(T2
)
3866 and then (Is_Constrained
(T1
) /= Is_Constrained
(T2
))
3871 -- If there was an error in either range, then just assume
3872 -- the types statically match to avoid further junk errors
3874 if Error_Posted
(Scalar_Range
(T1
))
3876 Error_Posted
(Scalar_Range
(T2
))
3881 -- Otherwise both types have bound that can be compared
3884 LB1
: constant Node_Id
:= Type_Low_Bound
(T1
);
3885 HB1
: constant Node_Id
:= Type_High_Bound
(T1
);
3886 LB2
: constant Node_Id
:= Type_Low_Bound
(T2
);
3887 HB2
: constant Node_Id
:= Type_High_Bound
(T2
);
3890 -- If the bounds are the same tree node, then match
3892 if LB1
= LB2
and then HB1
= HB2
then
3895 -- Otherwise bounds must be static and identical value
3898 if not Is_Static_Subtype
(T1
)
3899 or else not Is_Static_Subtype
(T2
)
3903 -- If either type has constraint error bounds, then say
3904 -- that they match to avoid junk cascaded errors here.
3906 elsif not Is_OK_Static_Subtype
(T1
)
3907 or else not Is_OK_Static_Subtype
(T2
)
3911 elsif Is_Real_Type
(T1
) then
3913 (Expr_Value_R
(LB1
) = Expr_Value_R
(LB2
))
3915 (Expr_Value_R
(HB1
) = Expr_Value_R
(HB2
));
3919 Expr_Value
(LB1
) = Expr_Value
(LB2
)
3921 Expr_Value
(HB1
) = Expr_Value
(HB2
);
3926 -- Type with discriminants
3928 elsif Has_Discriminants
(T1
) or else Has_Discriminants
(T2
) then
3930 -- Because of view exchanges in multiple instantiations, conformance
3931 -- checking might try to match a partial view of a type with no
3932 -- discriminants with a full view that has defaulted discriminants.
3933 -- In such a case, use the discriminant constraint of the full view,
3934 -- which must exist because we know that the two subtypes have the
3937 if Has_Discriminants
(T1
) /= Has_Discriminants
(T2
) then
3939 if Is_Private_Type
(T2
)
3940 and then Present
(Full_View
(T2
))
3941 and then Has_Discriminants
(Full_View
(T2
))
3943 return Subtypes_Statically_Match
(T1
, Full_View
(T2
));
3945 elsif Is_Private_Type
(T1
)
3946 and then Present
(Full_View
(T1
))
3947 and then Has_Discriminants
(Full_View
(T1
))
3949 return Subtypes_Statically_Match
(Full_View
(T1
), T2
);
3960 DL1
: constant Elist_Id
:= Discriminant_Constraint
(T1
);
3961 DL2
: constant Elist_Id
:= Discriminant_Constraint
(T2
);
3963 DA1
: Elmt_Id
:= First_Elmt
(DL1
);
3964 DA2
: Elmt_Id
:= First_Elmt
(DL2
);
3970 elsif Is_Constrained
(T1
) /= Is_Constrained
(T2
) then
3974 while Present
(DA1
) loop
3976 Expr1
: constant Node_Id
:= Node
(DA1
);
3977 Expr2
: constant Node_Id
:= Node
(DA2
);
3980 if not Is_Static_Expression
(Expr1
)
3981 or else not Is_Static_Expression
(Expr2
)
3985 -- If either expression raised a constraint error,
3986 -- consider the expressions as matching, since this
3987 -- helps to prevent cascading errors.
3989 elsif Raises_Constraint_Error
(Expr1
)
3990 or else Raises_Constraint_Error
(Expr2
)
3994 elsif Expr_Value
(Expr1
) /= Expr_Value
(Expr2
) then
4006 -- A definite type does not match an indefinite or classwide type
4009 Has_Unknown_Discriminants
(T1
) /= Has_Unknown_Discriminants
(T2
)
4015 elsif Is_Array_Type
(T1
) then
4017 -- If either subtype is unconstrained then both must be,
4018 -- and if both are unconstrained then no further checking
4021 if not Is_Constrained
(T1
) or else not Is_Constrained
(T2
) then
4022 return not (Is_Constrained
(T1
) or else Is_Constrained
(T2
));
4025 -- Both subtypes are constrained, so check that the index
4026 -- subtypes statically match.
4029 Index1
: Node_Id
:= First_Index
(T1
);
4030 Index2
: Node_Id
:= First_Index
(T2
);
4033 while Present
(Index1
) loop
4035 Subtypes_Statically_Match
(Etype
(Index1
), Etype
(Index2
))
4040 Next_Index
(Index1
);
4041 Next_Index
(Index2
);
4047 elsif Is_Access_Type
(T1
) then
4048 return Subtypes_Statically_Match
4049 (Designated_Type
(T1
),
4050 Designated_Type
(T2
));
4052 -- All other types definitely match
4057 end Subtypes_Statically_Match
;
4063 function Test
(Cond
: Boolean) return Uint
is
4072 ---------------------------------
4073 -- Test_Expression_Is_Foldable --
4074 ---------------------------------
4078 procedure Test_Expression_Is_Foldable
4087 -- If operand is Any_Type, just propagate to result and do not
4088 -- try to fold, this prevents cascaded errors.
4090 if Etype
(Op1
) = Any_Type
then
4091 Set_Etype
(N
, Any_Type
);
4095 -- If operand raises constraint error, then replace node N with the
4096 -- raise constraint error node, and we are obviously not foldable.
4097 -- Note that this replacement inherits the Is_Static_Expression flag
4098 -- from the operand.
4100 elsif Raises_Constraint_Error
(Op1
) then
4101 Rewrite_In_Raise_CE
(N
, Op1
);
4105 -- If the operand is not static, then the result is not static, and
4106 -- all we have to do is to check the operand since it is now known
4107 -- to appear in a non-static context.
4109 elsif not Is_Static_Expression
(Op1
) then
4110 Check_Non_Static_Context
(Op1
);
4111 Fold
:= Compile_Time_Known_Value
(Op1
);
4114 -- An expression of a formal modular type is not foldable because
4115 -- the modulus is unknown.
4117 elsif Is_Modular_Integer_Type
(Etype
(Op1
))
4118 and then Is_Generic_Type
(Etype
(Op1
))
4120 Check_Non_Static_Context
(Op1
);
4124 -- Here we have the case of an operand whose type is OK, which is
4125 -- static, and which does not raise constraint error, we can fold.
4128 Set_Is_Static_Expression
(N
);
4132 end Test_Expression_Is_Foldable
;
4136 procedure Test_Expression_Is_Foldable
4143 Rstat
: constant Boolean := Is_Static_Expression
(Op1
)
4144 and then Is_Static_Expression
(Op2
);
4149 -- If either operand is Any_Type, just propagate to result and
4150 -- do not try to fold, this prevents cascaded errors.
4152 if Etype
(Op1
) = Any_Type
or else Etype
(Op2
) = Any_Type
then
4153 Set_Etype
(N
, Any_Type
);
4157 -- If left operand raises constraint error, then replace node N with
4158 -- the raise constraint error node, and we are obviously not foldable.
4159 -- Is_Static_Expression is set from the two operands in the normal way,
4160 -- and we check the right operand if it is in a non-static context.
4162 elsif Raises_Constraint_Error
(Op1
) then
4164 Check_Non_Static_Context
(Op2
);
4167 Rewrite_In_Raise_CE
(N
, Op1
);
4168 Set_Is_Static_Expression
(N
, Rstat
);
4172 -- Similar processing for the case of the right operand. Note that
4173 -- we don't use this routine for the short-circuit case, so we do
4174 -- not have to worry about that special case here.
4176 elsif Raises_Constraint_Error
(Op2
) then
4178 Check_Non_Static_Context
(Op1
);
4181 Rewrite_In_Raise_CE
(N
, Op2
);
4182 Set_Is_Static_Expression
(N
, Rstat
);
4186 -- Exclude expressions of a generic modular type, as above
4188 elsif Is_Modular_Integer_Type
(Etype
(Op1
))
4189 and then Is_Generic_Type
(Etype
(Op1
))
4191 Check_Non_Static_Context
(Op1
);
4195 -- If result is not static, then check non-static contexts on operands
4196 -- since one of them may be static and the other one may not be static
4198 elsif not Rstat
then
4199 Check_Non_Static_Context
(Op1
);
4200 Check_Non_Static_Context
(Op2
);
4201 Fold
:= Compile_Time_Known_Value
(Op1
)
4202 and then Compile_Time_Known_Value
(Op2
);
4205 -- Else result is static and foldable. Both operands are static,
4206 -- and neither raises constraint error, so we can definitely fold.
4209 Set_Is_Static_Expression
(N
);
4214 end Test_Expression_Is_Foldable
;
4220 procedure To_Bits
(U
: Uint
; B
: out Bits
) is
4222 for J
in 0 .. B
'Last loop
4223 B
(J
) := (U
/ (2 ** J
)) mod 2 /= 0;
4227 --------------------
4228 -- Why_Not_Static --
4229 --------------------
4231 procedure Why_Not_Static
(Expr
: Node_Id
) is
4232 N
: constant Node_Id
:= Original_Node
(Expr
);
4236 procedure Why_Not_Static_List
(L
: List_Id
);
4237 -- A version that can be called on a list of expressions. Finds
4238 -- all non-static violations in any element of the list.
4240 -------------------------
4241 -- Why_Not_Static_List --
4242 -------------------------
4244 procedure Why_Not_Static_List
(L
: List_Id
) is
4248 if Is_Non_Empty_List
(L
) then
4250 while Present
(N
) loop
4255 end Why_Not_Static_List
;
4257 -- Start of processing for Why_Not_Static
4260 -- If in ACATS mode (debug flag 2), then suppress all these
4261 -- messages, this avoids massive updates to the ACATS base line.
4263 if Debug_Flag_2
then
4267 -- Ignore call on error or empty node
4269 if No
(Expr
) or else Nkind
(Expr
) = N_Error
then
4273 -- Preprocessing for sub expressions
4275 if Nkind
(Expr
) in N_Subexpr
then
4277 -- Nothing to do if expression is static
4279 if Is_OK_Static_Expression
(Expr
) then
4283 -- Test for constraint error raised
4285 if Raises_Constraint_Error
(Expr
) then
4287 ("expression raises exception, cannot be static " &
4288 "('R'M 4.9(34))!", N
);
4292 -- If no type, then something is pretty wrong, so ignore
4294 Typ
:= Etype
(Expr
);
4300 -- Type must be scalar or string type
4302 if not Is_Scalar_Type
(Typ
)
4303 and then not Is_String_Type
(Typ
)
4306 ("static expression must have scalar or string type " &
4307 "('R'M 4.9(2))!", N
);
4312 -- If we got through those checks, test particular node kind
4315 when N_Expanded_Name | N_Identifier | N_Operator_Symbol
=>
4318 if Is_Named_Number
(E
) then
4321 elsif Ekind
(E
) = E_Constant
then
4322 if not Is_Static_Expression
(Constant_Value
(E
)) then
4324 ("& is not a static constant ('R'M 4.9(5))!", N
, E
);
4329 ("& is not static constant or named number " &
4330 "('R'M 4.9(5))!", N
, E
);
4333 when N_Binary_Op | N_And_Then | N_Or_Else | N_In | N_Not_In
=>
4334 if Nkind
(N
) in N_Op_Shift
then
4336 ("shift functions are never static ('R'M 4.9(6,18))!", N
);
4339 Why_Not_Static
(Left_Opnd
(N
));
4340 Why_Not_Static
(Right_Opnd
(N
));
4344 Why_Not_Static
(Right_Opnd
(N
));
4346 when N_Attribute_Reference
=>
4347 Why_Not_Static_List
(Expressions
(N
));
4349 E
:= Etype
(Prefix
(N
));
4351 if E
= Standard_Void_Type
then
4355 -- Special case non-scalar'Size since this is a common error
4357 if Attribute_Name
(N
) = Name_Size
then
4359 ("size attribute is only static for scalar type " &
4360 "('R'M 4.9(7,8))", N
);
4364 elsif Is_Array_Type
(E
) then
4365 if Attribute_Name
(N
) /= Name_First
4367 Attribute_Name
(N
) /= Name_Last
4369 Attribute_Name
(N
) /= Name_Length
4372 ("static array attribute must be Length, First, or Last " &
4373 "('R'M 4.9(8))!", N
);
4375 -- Since we know the expression is not-static (we already
4376 -- tested for this, must mean array is not static).
4380 ("prefix is non-static array ('R'M 4.9(8))!", Prefix
(N
));
4385 -- Special case generic types, since again this is a common
4386 -- source of confusion.
4388 elsif Is_Generic_Actual_Type
(E
)
4393 ("attribute of generic type is never static " &
4394 "('R'M 4.9(7,8))!", N
);
4396 elsif Is_Static_Subtype
(E
) then
4399 elsif Is_Scalar_Type
(E
) then
4401 ("prefix type for attribute is not static scalar subtype " &
4402 "('R'M 4.9(7))!", N
);
4406 ("static attribute must apply to array/scalar type " &
4407 "('R'M 4.9(7,8))!", N
);
4410 when N_String_Literal
=>
4412 ("subtype of string literal is non-static ('R'M 4.9(4))!", N
);
4414 when N_Explicit_Dereference
=>
4416 ("explicit dereference is never static ('R'M 4.9)!", N
);
4418 when N_Function_Call
=>
4419 Why_Not_Static_List
(Parameter_Associations
(N
));
4420 Error_Msg_N
("non-static function call ('R'M 4.9(6,18))!", N
);
4422 when N_Parameter_Association
=>
4423 Why_Not_Static
(Explicit_Actual_Parameter
(N
));
4425 when N_Indexed_Component
=>
4427 ("indexed component is never static ('R'M 4.9)!", N
);
4429 when N_Procedure_Call_Statement
=>
4431 ("procedure call is never static ('R'M 4.9)!", N
);
4433 when N_Qualified_Expression
=>
4434 Why_Not_Static
(Expression
(N
));
4436 when N_Aggregate | N_Extension_Aggregate
=>
4438 ("an aggregate is never static ('R'M 4.9)!", N
);
4441 Why_Not_Static
(Low_Bound
(N
));
4442 Why_Not_Static
(High_Bound
(N
));
4444 when N_Range_Constraint
=>
4445 Why_Not_Static
(Range_Expression
(N
));
4447 when N_Subtype_Indication
=>
4448 Why_Not_Static
(Constraint
(N
));
4450 when N_Selected_Component
=>
4452 ("selected component is never static ('R'M 4.9)!", N
);
4456 ("slice is never static ('R'M 4.9)!", N
);
4458 when N_Type_Conversion
=>
4459 Why_Not_Static
(Expression
(N
));
4461 if not Is_Scalar_Type
(Etype
(Prefix
(N
)))
4462 or else not Is_Static_Subtype
(Etype
(Prefix
(N
)))
4465 ("static conversion requires static scalar subtype result " &
4466 "('R'M 4.9(9))!", N
);
4469 when N_Unchecked_Type_Conversion
=>
4471 ("unchecked type conversion is never static ('R'M 4.9)!", N
);