1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2013, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree
; use Atree
;
27 with Checks
; use Checks
;
28 with Debug
; use Debug
;
29 with Einfo
; use Einfo
;
30 with Elists
; use Elists
;
31 with Errout
; use Errout
;
32 with Eval_Fat
; use Eval_Fat
;
33 with Exp_Util
; use Exp_Util
;
34 with Freeze
; use Freeze
;
36 with Namet
; use Namet
;
37 with Nmake
; use Nmake
;
38 with Nlists
; use Nlists
;
40 with Rtsfind
; use Rtsfind
;
42 with Sem_Aux
; use Sem_Aux
;
43 with Sem_Cat
; use Sem_Cat
;
44 with Sem_Ch6
; use Sem_Ch6
;
45 with Sem_Ch8
; use Sem_Ch8
;
46 with Sem_Res
; use Sem_Res
;
47 with Sem_Util
; use Sem_Util
;
48 with Sem_Type
; use Sem_Type
;
49 with Sem_Warn
; use Sem_Warn
;
50 with Sinfo
; use Sinfo
;
51 with Snames
; use Snames
;
52 with Stand
; use Stand
;
53 with Stringt
; use Stringt
;
54 with Tbuild
; use Tbuild
;
56 package body Sem_Eval
is
58 -----------------------------------------
59 -- Handling of Compile Time Evaluation --
60 -----------------------------------------
62 -- The compile time evaluation of expressions is distributed over several
63 -- Eval_xxx procedures. These procedures are called immediately after
64 -- a subexpression is resolved and is therefore accomplished in a bottom
65 -- up fashion. The flags are synthesized using the following approach.
67 -- Is_Static_Expression is determined by following the detailed rules
68 -- in RM 4.9(4-14). This involves testing the Is_Static_Expression
69 -- flag of the operands in many cases.
71 -- Raises_Constraint_Error is set if any of the operands have the flag
72 -- set or if an attempt to compute the value of the current expression
73 -- results in detection of a runtime constraint error.
75 -- As described in the spec, the requirement is that Is_Static_Expression
76 -- be accurately set, and in addition for nodes for which this flag is set,
77 -- Raises_Constraint_Error must also be set. Furthermore a node which has
78 -- Is_Static_Expression set, and Raises_Constraint_Error clear, then the
79 -- requirement is that the expression value must be precomputed, and the
80 -- node is either a literal, or the name of a constant entity whose value
81 -- is a static expression.
83 -- The general approach is as follows. First compute Is_Static_Expression.
84 -- If the node is not static, then the flag is left off in the node and
85 -- we are all done. Otherwise for a static node, we test if any of the
86 -- operands will raise constraint error, and if so, propagate the flag
87 -- Raises_Constraint_Error to the result node and we are done (since the
88 -- error was already posted at a lower level).
90 -- For the case of a static node whose operands do not raise constraint
91 -- error, we attempt to evaluate the node. If this evaluation succeeds,
92 -- then the node is replaced by the result of this computation. If the
93 -- evaluation raises constraint error, then we rewrite the node with
94 -- Apply_Compile_Time_Constraint_Error to raise the exception and also
95 -- to post appropriate error messages.
101 type Bits
is array (Nat
range <>) of Boolean;
102 -- Used to convert unsigned (modular) values for folding logical ops
104 -- The following definitions are used to maintain a cache of nodes that
105 -- have compile time known values. The cache is maintained only for
106 -- discrete types (the most common case), and is populated by calls to
107 -- Compile_Time_Known_Value and Expr_Value, but only used by Expr_Value
108 -- since it is possible for the status to change (in particular it is
109 -- possible for a node to get replaced by a constraint error node).
111 CV_Bits
: constant := 5;
112 -- Number of low order bits of Node_Id value used to reference entries
113 -- in the cache table.
115 CV_Cache_Size
: constant Nat
:= 2 ** CV_Bits
;
116 -- Size of cache for compile time values
118 subtype CV_Range
is Nat
range 0 .. CV_Cache_Size
;
120 type CV_Entry
is record
125 type CV_Cache_Array
is array (CV_Range
) of CV_Entry
;
127 CV_Cache
: CV_Cache_Array
:= (others => (Node_High_Bound
, Uint_0
));
128 -- This is the actual cache, with entries consisting of node/value pairs,
129 -- and the impossible value Node_High_Bound used for unset entries.
131 type Range_Membership
is (In_Range
, Out_Of_Range
, Unknown
);
132 -- Range membership may either be statically known to be in range or out
133 -- of range, or not statically known. Used for Test_In_Range below.
135 -----------------------
136 -- Local Subprograms --
137 -----------------------
139 function From_Bits
(B
: Bits
; T
: Entity_Id
) return Uint
;
140 -- Converts a bit string of length B'Length to a Uint value to be used
141 -- for a target of type T, which is a modular type. This procedure
142 -- includes the necessary reduction by the modulus in the case of a
143 -- non-binary modulus (for a binary modulus, the bit string is the
144 -- right length any way so all is well).
146 function Get_String_Val
(N
: Node_Id
) return Node_Id
;
147 -- Given a tree node for a folded string or character value, returns
148 -- the corresponding string literal or character literal (one of the
149 -- two must be available, or the operand would not have been marked
150 -- as foldable in the earlier analysis of the operation).
152 function OK_Bits
(N
: Node_Id
; Bits
: Uint
) return Boolean;
153 -- Bits represents the number of bits in an integer value to be computed
154 -- (but the value has not been computed yet). If this value in Bits is
155 -- reasonable, a result of True is returned, with the implication that
156 -- the caller should go ahead and complete the calculation. If the value
157 -- in Bits is unreasonably large, then an error is posted on node N, and
158 -- False is returned (and the caller skips the proposed calculation).
160 procedure Out_Of_Range
(N
: Node_Id
);
161 -- This procedure is called if it is determined that node N, which
162 -- appears in a non-static context, is a compile time known value
163 -- which is outside its range, i.e. the range of Etype. This is used
164 -- in contexts where this is an illegality if N is static, and should
165 -- generate a warning otherwise.
167 procedure Rewrite_In_Raise_CE
(N
: Node_Id
; Exp
: Node_Id
);
168 -- N and Exp are nodes representing an expression, Exp is known
169 -- to raise CE. N is rewritten in term of Exp in the optimal way.
171 function String_Type_Len
(Stype
: Entity_Id
) return Uint
;
172 -- Given a string type, determines the length of the index type, or,
173 -- if this index type is non-static, the length of the base type of
174 -- this index type. Note that if the string type is itself static,
175 -- then the index type is static, so the second case applies only
176 -- if the string type passed is non-static.
178 function Test
(Cond
: Boolean) return Uint
;
179 pragma Inline
(Test
);
180 -- This function simply returns the appropriate Boolean'Pos value
181 -- corresponding to the value of Cond as a universal integer. It is
182 -- used for producing the result of the static evaluation of the
185 function Find_Universal_Operator_Type
(N
: Node_Id
) return Entity_Id
;
186 -- Check whether an arithmetic operation with universal operands which
187 -- is a rewritten function call with an explicit scope indication is
188 -- ambiguous: P."+" (1, 2) will be ambiguous if there is more than one
189 -- visible numeric type declared in P and the context does not impose a
190 -- type on the result (e.g. in the expression of a type conversion).
191 -- If ambiguous, emit an error and return Empty, else return the result
192 -- type of the operator.
194 procedure Test_Expression_Is_Foldable
199 -- Tests to see if expression N whose single operand is Op1 is foldable,
200 -- i.e. the operand value is known at compile time. If the operation is
201 -- foldable, then Fold is True on return, and Stat indicates whether
202 -- the result is static (i.e. the operand was static). Note that it
203 -- is quite possible for Fold to be True, and Stat to be False, since
204 -- there are cases in which we know the value of an operand even though
205 -- it is not technically static (e.g. the static lower bound of a range
206 -- whose upper bound is non-static).
208 -- If Stat is set False on return, then Test_Expression_Is_Foldable makes a
209 -- call to Check_Non_Static_Context on the operand. If Fold is False on
210 -- return, then all processing is complete, and the caller should
211 -- return, since there is nothing else to do.
213 -- If Stat is set True on return, then Is_Static_Expression is also set
214 -- true in node N. There are some cases where this is over-enthusiastic,
215 -- e.g. in the two operand case below, for string comparison, the result
216 -- is not static even though the two operands are static. In such cases,
217 -- the caller must reset the Is_Static_Expression flag in N.
219 -- If Fold and Stat are both set to False then this routine performs also
220 -- the following extra actions:
222 -- If either operand is Any_Type then propagate it to result to
223 -- prevent cascaded errors.
225 -- If some operand raises constraint error, then replace the node N
226 -- with the raise constraint error node. This replacement inherits the
227 -- Is_Static_Expression flag from the operands.
229 procedure Test_Expression_Is_Foldable
235 CRT_Safe
: Boolean := False);
236 -- Same processing, except applies to an expression N with two operands
237 -- Op1 and Op2. The result is static only if both operands are static. If
238 -- CRT_Safe is set True, then CRT_Safe_Compile_Time_Known_Value is used
239 -- for the tests that the two operands are known at compile time. See
240 -- spec of this routine for further details.
242 function Test_In_Range
245 Assume_Valid
: Boolean;
247 Int_Real
: Boolean) return Range_Membership
;
248 -- Common processing for Is_In_Range and Is_Out_Of_Range: Returns In_Range
249 -- or Out_Of_Range if it can be guaranteed at compile time that expression
250 -- N is known to be in or out of range of the subtype Typ. If not compile
251 -- time known, Unknown is returned. See documentation of Is_In_Range for
252 -- complete description of parameters.
254 procedure To_Bits
(U
: Uint
; B
: out Bits
);
255 -- Converts a Uint value to a bit string of length B'Length
257 ------------------------------
258 -- Check_Non_Static_Context --
259 ------------------------------
261 procedure Check_Non_Static_Context
(N
: Node_Id
) is
262 T
: constant Entity_Id
:= Etype
(N
);
263 Checks_On
: constant Boolean :=
264 not Index_Checks_Suppressed
(T
)
265 and not Range_Checks_Suppressed
(T
);
268 -- Ignore cases of non-scalar types, error types, or universal real
269 -- types that have no usable bounds.
272 or else not Is_Scalar_Type
(T
)
273 or else T
= Universal_Fixed
274 or else T
= Universal_Real
279 -- At this stage we have a scalar type. If we have an expression that
280 -- raises CE, then we already issued a warning or error msg so there
281 -- is nothing more to be done in this routine.
283 if Raises_Constraint_Error
(N
) then
287 -- Now we have a scalar type which is not marked as raising a constraint
288 -- error exception. The main purpose of this routine is to deal with
289 -- static expressions appearing in a non-static context. That means
290 -- that if we do not have a static expression then there is not much
291 -- to do. The one case that we deal with here is that if we have a
292 -- floating-point value that is out of range, then we post a warning
293 -- that an infinity will result.
295 if not Is_Static_Expression
(N
) then
296 if Is_Floating_Point_Type
(T
)
297 and then Is_Out_Of_Range
(N
, Base_Type
(T
), Assume_Valid
=> True)
300 ("??float value out of range, infinity will be generated", N
);
306 -- Here we have the case of outer level static expression of scalar
307 -- type, where the processing of this procedure is needed.
309 -- For real types, this is where we convert the value to a machine
310 -- number (see RM 4.9(38)). Also see ACVC test C490001. We should only
311 -- need to do this if the parent is a constant declaration, since in
312 -- other cases, gigi should do the necessary conversion correctly, but
313 -- experimentation shows that this is not the case on all machines, in
314 -- particular if we do not convert all literals to machine values in
315 -- non-static contexts, then ACVC test C490001 fails on Sparc/Solaris
318 if Nkind
(N
) = N_Real_Literal
319 and then not Is_Machine_Number
(N
)
320 and then not Is_Generic_Type
(Etype
(N
))
321 and then Etype
(N
) /= Universal_Real
323 -- Check that value is in bounds before converting to machine
324 -- number, so as not to lose case where value overflows in the
325 -- least significant bit or less. See B490001.
327 if Is_Out_Of_Range
(N
, Base_Type
(T
), Assume_Valid
=> True) then
332 -- Note: we have to copy the node, to avoid problems with conformance
333 -- of very similar numbers (see ACVC tests B4A010C and B63103A).
335 Rewrite
(N
, New_Copy
(N
));
337 if not Is_Floating_Point_Type
(T
) then
339 (N
, Corresponding_Integer_Value
(N
) * Small_Value
(T
));
341 elsif not UR_Is_Zero
(Realval
(N
)) then
343 -- Note: even though RM 4.9(38) specifies biased rounding, this
344 -- has been modified by AI-100 in order to prevent confusing
345 -- differences in rounding between static and non-static
346 -- expressions. AI-100 specifies that the effect of such rounding
347 -- is implementation dependent, and in GNAT we round to nearest
348 -- even to match the run-time behavior.
351 (N
, Machine
(Base_Type
(T
), Realval
(N
), Round_Even
, N
));
354 Set_Is_Machine_Number
(N
);
357 -- Check for out of range universal integer. This is a non-static
358 -- context, so the integer value must be in range of the runtime
359 -- representation of universal integers.
361 -- We do this only within an expression, because that is the only
362 -- case in which non-static universal integer values can occur, and
363 -- furthermore, Check_Non_Static_Context is currently (incorrectly???)
364 -- called in contexts like the expression of a number declaration where
365 -- we certainly want to allow out of range values.
367 if Etype
(N
) = Universal_Integer
368 and then Nkind
(N
) = N_Integer_Literal
369 and then Nkind
(Parent
(N
)) in N_Subexpr
371 (Intval
(N
) < Expr_Value
(Type_Low_Bound
(Universal_Integer
))
373 Intval
(N
) > Expr_Value
(Type_High_Bound
(Universal_Integer
)))
375 Apply_Compile_Time_Constraint_Error
376 (N
, "non-static universal integer value out of range<<",
377 CE_Range_Check_Failed
);
379 -- Check out of range of base type
381 elsif Is_Out_Of_Range
(N
, Base_Type
(T
), Assume_Valid
=> True) then
384 -- Give warning if outside subtype (where one or both of the bounds of
385 -- the subtype is static). This warning is omitted if the expression
386 -- appears in a range that could be null (warnings are handled elsewhere
389 elsif T
/= Base_Type
(T
)
390 and then Nkind
(Parent
(N
)) /= N_Range
392 if Is_In_Range
(N
, T
, Assume_Valid
=> True) then
395 elsif Is_Out_Of_Range
(N
, T
, Assume_Valid
=> True) then
396 Apply_Compile_Time_Constraint_Error
397 (N
, "value not in range of}<<", CE_Range_Check_Failed
);
400 Enable_Range_Check
(N
);
403 Set_Do_Range_Check
(N
, False);
406 end Check_Non_Static_Context
;
408 ---------------------------------
409 -- Check_String_Literal_Length --
410 ---------------------------------
412 procedure Check_String_Literal_Length
(N
: Node_Id
; Ttype
: Entity_Id
) is
414 if not Raises_Constraint_Error
(N
) and then Is_Constrained
(Ttype
) then
416 UI_From_Int
(String_Length
(Strval
(N
))) /= String_Type_Len
(Ttype
)
418 Apply_Compile_Time_Constraint_Error
419 (N
, "string length wrong for}??",
420 CE_Length_Check_Failed
,
425 end Check_String_Literal_Length
;
427 --------------------------
428 -- Compile_Time_Compare --
429 --------------------------
431 function Compile_Time_Compare
433 Assume_Valid
: Boolean) return Compare_Result
435 Discard
: aliased Uint
;
437 return Compile_Time_Compare
(L
, R
, Discard
'Access, Assume_Valid
);
438 end Compile_Time_Compare
;
440 function Compile_Time_Compare
443 Assume_Valid
: Boolean;
444 Rec
: Boolean := False) return Compare_Result
446 Ltyp
: Entity_Id
:= Underlying_Type
(Etype
(L
));
447 Rtyp
: Entity_Id
:= Underlying_Type
(Etype
(R
));
448 -- These get reset to the base type for the case of entities where
449 -- Is_Known_Valid is not set. This takes care of handling possible
450 -- invalid representations using the value of the base type, in
451 -- accordance with RM 13.9.1(10).
453 Discard
: aliased Uint
;
455 procedure Compare_Decompose
459 -- This procedure decomposes the node N into an expression node and a
460 -- signed offset, so that the value of N is equal to the value of R plus
461 -- the value V (which may be negative). If no such decomposition is
462 -- possible, then on return R is a copy of N, and V is set to zero.
464 function Compare_Fixup
(N
: Node_Id
) return Node_Id
;
465 -- This function deals with replacing 'Last and 'First references with
466 -- their corresponding type bounds, which we then can compare. The
467 -- argument is the original node, the result is the identity, unless we
468 -- have a 'Last/'First reference in which case the value returned is the
469 -- appropriate type bound.
471 function Is_Known_Valid_Operand
(Opnd
: Node_Id
) return Boolean;
472 -- Even if the context does not assume that values are valid, some
473 -- simple cases can be recognized.
475 function Is_Same_Value
(L
, R
: Node_Id
) return Boolean;
476 -- Returns True iff L and R represent expressions that definitely have
477 -- identical (but not necessarily compile time known) values Indeed the
478 -- caller is expected to have already dealt with the cases of compile
479 -- time known values, so these are not tested here.
481 -----------------------
482 -- Compare_Decompose --
483 -----------------------
485 procedure Compare_Decompose
491 if Nkind
(N
) = N_Op_Add
492 and then Nkind
(Right_Opnd
(N
)) = N_Integer_Literal
495 V
:= Intval
(Right_Opnd
(N
));
498 elsif Nkind
(N
) = N_Op_Subtract
499 and then Nkind
(Right_Opnd
(N
)) = N_Integer_Literal
502 V
:= UI_Negate
(Intval
(Right_Opnd
(N
)));
505 elsif Nkind
(N
) = N_Attribute_Reference
then
506 if Attribute_Name
(N
) = Name_Succ
then
507 R
:= First
(Expressions
(N
));
511 elsif Attribute_Name
(N
) = Name_Pred
then
512 R
:= First
(Expressions
(N
));
520 end Compare_Decompose
;
526 function Compare_Fixup
(N
: Node_Id
) return Node_Id
is
532 -- Fixup only required for First/Last attribute reference
534 if Nkind
(N
) = N_Attribute_Reference
535 and then Nam_In
(Attribute_Name
(N
), Name_First
, Name_Last
)
537 Xtyp
:= Etype
(Prefix
(N
));
539 -- If we have no type, then just abandon the attempt to do
540 -- a fixup, this is probably the result of some other error.
546 -- Dereference an access type
548 if Is_Access_Type
(Xtyp
) then
549 Xtyp
:= Designated_Type
(Xtyp
);
552 -- If we don't have an array type at this stage, something
553 -- is peculiar, e.g. another error, and we abandon the attempt
556 if not Is_Array_Type
(Xtyp
) then
560 -- Ignore unconstrained array, since bounds are not meaningful
562 if not Is_Constrained
(Xtyp
) then
566 if Ekind
(Xtyp
) = E_String_Literal_Subtype
then
567 if Attribute_Name
(N
) = Name_First
then
568 return String_Literal_Low_Bound
(Xtyp
);
571 return Make_Integer_Literal
(Sloc
(N
),
572 Intval
=> Intval
(String_Literal_Low_Bound
(Xtyp
))
573 + String_Literal_Length
(Xtyp
));
577 -- Find correct index type
579 Indx
:= First_Index
(Xtyp
);
581 if Present
(Expressions
(N
)) then
582 Subs
:= UI_To_Int
(Expr_Value
(First
(Expressions
(N
))));
584 for J
in 2 .. Subs
loop
585 Indx
:= Next_Index
(Indx
);
589 Xtyp
:= Etype
(Indx
);
591 if Attribute_Name
(N
) = Name_First
then
592 return Type_Low_Bound
(Xtyp
);
594 return Type_High_Bound
(Xtyp
);
601 ----------------------------
602 -- Is_Known_Valid_Operand --
603 ----------------------------
605 function Is_Known_Valid_Operand
(Opnd
: Node_Id
) return Boolean is
607 return (Is_Entity_Name
(Opnd
)
609 (Is_Known_Valid
(Entity
(Opnd
))
610 or else Ekind
(Entity
(Opnd
)) = E_In_Parameter
612 (Ekind
(Entity
(Opnd
)) in Object_Kind
613 and then Present
(Current_Value
(Entity
(Opnd
))))))
614 or else Is_OK_Static_Expression
(Opnd
);
615 end Is_Known_Valid_Operand
;
621 function Is_Same_Value
(L
, R
: Node_Id
) return Boolean is
622 Lf
: constant Node_Id
:= Compare_Fixup
(L
);
623 Rf
: constant Node_Id
:= Compare_Fixup
(R
);
625 function Is_Same_Subscript
(L
, R
: List_Id
) return Boolean;
626 -- L, R are the Expressions values from two attribute nodes for First
627 -- or Last attributes. Either may be set to No_List if no expressions
628 -- are present (indicating subscript 1). The result is True if both
629 -- expressions represent the same subscript (note one case is where
630 -- one subscript is missing and the other is explicitly set to 1).
632 -----------------------
633 -- Is_Same_Subscript --
634 -----------------------
636 function Is_Same_Subscript
(L
, R
: List_Id
) return Boolean is
642 return Expr_Value
(First
(R
)) = Uint_1
;
647 return Expr_Value
(First
(L
)) = Uint_1
;
649 return Expr_Value
(First
(L
)) = Expr_Value
(First
(R
));
652 end Is_Same_Subscript
;
654 -- Start of processing for Is_Same_Value
657 -- Values are the same if they refer to the same entity and the
658 -- entity is non-volatile. This does not however apply to Float
659 -- types, since we may have two NaN values and they should never
662 -- If the entity is a discriminant, the two expressions may be bounds
663 -- of components of objects of the same discriminated type. The
664 -- values of the discriminants are not static, and therefore the
665 -- result is unknown.
667 -- It would be better to comment individual branches of this test ???
669 if Nkind_In
(Lf
, N_Identifier
, N_Expanded_Name
)
670 and then Nkind_In
(Rf
, N_Identifier
, N_Expanded_Name
)
671 and then Entity
(Lf
) = Entity
(Rf
)
672 and then Ekind
(Entity
(Lf
)) /= E_Discriminant
673 and then Present
(Entity
(Lf
))
674 and then not Is_Floating_Point_Type
(Etype
(L
))
675 and then not Is_Volatile_Reference
(L
)
676 and then not Is_Volatile_Reference
(R
)
680 -- Or if they are compile time known and identical
682 elsif Compile_Time_Known_Value
(Lf
)
684 Compile_Time_Known_Value
(Rf
)
685 and then Expr_Value
(Lf
) = Expr_Value
(Rf
)
689 -- False if Nkind of the two nodes is different for remaining cases
691 elsif Nkind
(Lf
) /= Nkind
(Rf
) then
694 -- True if both 'First or 'Last values applying to the same entity
695 -- (first and last don't change even if value does). Note that we
696 -- need this even with the calls to Compare_Fixup, to handle the
697 -- case of unconstrained array attributes where Compare_Fixup
698 -- cannot find useful bounds.
700 elsif Nkind
(Lf
) = N_Attribute_Reference
701 and then Attribute_Name
(Lf
) = Attribute_Name
(Rf
)
702 and then Nam_In
(Attribute_Name
(Lf
), Name_First
, Name_Last
)
703 and then Nkind_In
(Prefix
(Lf
), N_Identifier
, N_Expanded_Name
)
704 and then Nkind_In
(Prefix
(Rf
), N_Identifier
, N_Expanded_Name
)
705 and then Entity
(Prefix
(Lf
)) = Entity
(Prefix
(Rf
))
706 and then Is_Same_Subscript
(Expressions
(Lf
), Expressions
(Rf
))
710 -- True if the same selected component from the same record
712 elsif Nkind
(Lf
) = N_Selected_Component
713 and then Selector_Name
(Lf
) = Selector_Name
(Rf
)
714 and then Is_Same_Value
(Prefix
(Lf
), Prefix
(Rf
))
718 -- True if the same unary operator applied to the same operand
720 elsif Nkind
(Lf
) in N_Unary_Op
721 and then Is_Same_Value
(Right_Opnd
(Lf
), Right_Opnd
(Rf
))
725 -- True if the same binary operator applied to the same operands
727 elsif Nkind
(Lf
) in N_Binary_Op
728 and then Is_Same_Value
(Left_Opnd
(Lf
), Left_Opnd
(Rf
))
729 and then Is_Same_Value
(Right_Opnd
(Lf
), Right_Opnd
(Rf
))
733 -- All other cases, we can't tell, so return False
740 -- Start of processing for Compile_Time_Compare
745 -- In preanalysis mode, always return Unknown unless the expression
746 -- is static. It is too early to be thinking we know the result of a
747 -- comparison, save that judgment for the full analysis. This is
748 -- particularly important in the case of pre and postconditions, which
749 -- otherwise can be prematurely collapsed into having True or False
750 -- conditions when this is inappropriate.
752 if not (Full_Analysis
753 or else (Is_Static_Expression
(L
)
755 Is_Static_Expression
(R
)))
760 -- If either operand could raise constraint error, then we cannot
761 -- know the result at compile time (since CE may be raised).
763 if not (Cannot_Raise_Constraint_Error
(L
)
765 Cannot_Raise_Constraint_Error
(R
))
770 -- Identical operands are most certainly equal
775 -- If expressions have no types, then do not attempt to determine if
776 -- they are the same, since something funny is going on. One case in
777 -- which this happens is during generic template analysis, when bounds
778 -- are not fully analyzed.
780 elsif No
(Ltyp
) or else No
(Rtyp
) then
783 -- We do not attempt comparisons for packed arrays arrays represented as
784 -- modular types, where the semantics of comparison is quite different.
786 elsif Is_Packed_Array_Type
(Ltyp
)
787 and then Is_Modular_Integer_Type
(Ltyp
)
791 -- For access types, the only time we know the result at compile time
792 -- (apart from identical operands, which we handled already) is if we
793 -- know one operand is null and the other is not, or both operands are
796 elsif Is_Access_Type
(Ltyp
) then
797 if Known_Null
(L
) then
798 if Known_Null
(R
) then
800 elsif Known_Non_Null
(R
) then
806 elsif Known_Non_Null
(L
) and then Known_Null
(R
) then
813 -- Case where comparison involves two compile time known values
815 elsif Compile_Time_Known_Value
(L
)
816 and then Compile_Time_Known_Value
(R
)
818 -- For the floating-point case, we have to be a little careful, since
819 -- at compile time we are dealing with universal exact values, but at
820 -- runtime, these will be in non-exact target form. That's why the
821 -- returned results are LE and GE below instead of LT and GT.
823 if Is_Floating_Point_Type
(Ltyp
)
825 Is_Floating_Point_Type
(Rtyp
)
828 Lo
: constant Ureal
:= Expr_Value_R
(L
);
829 Hi
: constant Ureal
:= Expr_Value_R
(R
);
841 -- For string types, we have two string literals and we proceed to
842 -- compare them using the Ada style dictionary string comparison.
844 elsif not Is_Scalar_Type
(Ltyp
) then
846 Lstring
: constant String_Id
:= Strval
(Expr_Value_S
(L
));
847 Rstring
: constant String_Id
:= Strval
(Expr_Value_S
(R
));
848 Llen
: constant Nat
:= String_Length
(Lstring
);
849 Rlen
: constant Nat
:= String_Length
(Rstring
);
852 for J
in 1 .. Nat
'Min (Llen
, Rlen
) loop
854 LC
: constant Char_Code
:= Get_String_Char
(Lstring
, J
);
855 RC
: constant Char_Code
:= Get_String_Char
(Rstring
, J
);
867 elsif Llen
> Rlen
then
874 -- For remaining scalar cases we know exactly (note that this does
875 -- include the fixed-point case, where we know the run time integer
880 Lo
: constant Uint
:= Expr_Value
(L
);
881 Hi
: constant Uint
:= Expr_Value
(R
);
898 -- Cases where at least one operand is not known at compile time
901 -- Remaining checks apply only for discrete types
903 if not Is_Discrete_Type
(Ltyp
)
904 or else not Is_Discrete_Type
(Rtyp
)
909 -- Defend against generic types, or actually any expressions that
910 -- contain a reference to a generic type from within a generic
911 -- template. We don't want to do any range analysis of such
912 -- expressions for two reasons. First, the bounds of a generic type
913 -- itself are junk and cannot be used for any kind of analysis.
914 -- Second, we may have a case where the range at run time is indeed
915 -- known, but we don't want to do compile time analysis in the
916 -- template based on that range since in an instance the value may be
917 -- static, and able to be elaborated without reference to the bounds
918 -- of types involved. As an example, consider:
920 -- (F'Pos (F'Last) + 1) > Integer'Last
922 -- The expression on the left side of > is Universal_Integer and thus
923 -- acquires the type Integer for evaluation at run time, and at run
924 -- time it is true that this condition is always False, but within
925 -- an instance F may be a type with a static range greater than the
926 -- range of Integer, and the expression statically evaluates to True.
928 if References_Generic_Formal_Type
(L
)
930 References_Generic_Formal_Type
(R
)
935 -- Replace types by base types for the case of entities which are
936 -- not known to have valid representations. This takes care of
937 -- properly dealing with invalid representations.
939 if not Assume_Valid
and then not Assume_No_Invalid_Values
then
940 if Is_Entity_Name
(L
) and then not Is_Known_Valid
(Entity
(L
)) then
941 Ltyp
:= Underlying_Type
(Base_Type
(Ltyp
));
944 if Is_Entity_Name
(R
) and then not Is_Known_Valid
(Entity
(R
)) then
945 Rtyp
:= Underlying_Type
(Base_Type
(Rtyp
));
949 -- First attempt is to decompose the expressions to extract a
950 -- constant offset resulting from the use of any of the forms:
957 -- Then we see if the two expressions are the same value, and if so
958 -- the result is obtained by comparing the offsets.
960 -- Note: the reason we do this test first is that it returns only
961 -- decisive results (with diff set), where other tests, like the
962 -- range test, may not be as so decisive. Consider for example
963 -- J .. J + 1. This code can conclude LT with a difference of 1,
964 -- even if the range of J is not known.
973 Compare_Decompose
(L
, Lnode
, Loffs
);
974 Compare_Decompose
(R
, Rnode
, Roffs
);
976 if Is_Same_Value
(Lnode
, Rnode
) then
977 if Loffs
= Roffs
then
980 elsif Loffs
< Roffs
then
981 Diff
.all := Roffs
- Loffs
;
985 Diff
.all := Loffs
- Roffs
;
991 -- Next, try range analysis and see if operand ranges are disjoint
999 -- True if each range is a single point
1002 Determine_Range
(L
, LOK
, LLo
, LHi
, Assume_Valid
);
1003 Determine_Range
(R
, ROK
, RLo
, RHi
, Assume_Valid
);
1006 Single
:= (LLo
= LHi
) and then (RLo
= RHi
);
1009 if Single
and Assume_Valid
then
1010 Diff
.all := RLo
- LLo
;
1015 elsif RHi
< LLo
then
1016 if Single
and Assume_Valid
then
1017 Diff
.all := LLo
- RLo
;
1022 elsif Single
and then LLo
= RLo
then
1024 -- If the range includes a single literal and we can assume
1025 -- validity then the result is known even if an operand is
1028 if Assume_Valid
then
1034 elsif LHi
= RLo
then
1037 elsif RHi
= LLo
then
1040 elsif not Is_Known_Valid_Operand
(L
)
1041 and then not Assume_Valid
1043 if Is_Same_Value
(L
, R
) then
1050 -- If the range of either operand cannot be determined, nothing
1051 -- further can be inferred.
1058 -- Here is where we check for comparisons against maximum bounds of
1059 -- types, where we know that no value can be outside the bounds of
1060 -- the subtype. Note that this routine is allowed to assume that all
1061 -- expressions are within their subtype bounds. Callers wishing to
1062 -- deal with possibly invalid values must in any case take special
1063 -- steps (e.g. conversions to larger types) to avoid this kind of
1064 -- optimization, which is always considered to be valid. We do not
1065 -- attempt this optimization with generic types, since the type
1066 -- bounds may not be meaningful in this case.
1068 -- We are in danger of an infinite recursion here. It does not seem
1069 -- useful to go more than one level deep, so the parameter Rec is
1070 -- used to protect ourselves against this infinite recursion.
1074 -- See if we can get a decisive check against one operand and
1075 -- a bound of the other operand (four possible tests here).
1076 -- Note that we avoid testing junk bounds of a generic type.
1078 if not Is_Generic_Type
(Rtyp
) then
1079 case Compile_Time_Compare
(L
, Type_Low_Bound
(Rtyp
),
1081 Assume_Valid
, Rec
=> True)
1083 when LT
=> return LT
;
1084 when LE
=> return LE
;
1085 when EQ
=> return LE
;
1086 when others => null;
1089 case Compile_Time_Compare
(L
, Type_High_Bound
(Rtyp
),
1091 Assume_Valid
, Rec
=> True)
1093 when GT
=> return GT
;
1094 when GE
=> return GE
;
1095 when EQ
=> return GE
;
1096 when others => null;
1100 if not Is_Generic_Type
(Ltyp
) then
1101 case Compile_Time_Compare
(Type_Low_Bound
(Ltyp
), R
,
1103 Assume_Valid
, Rec
=> True)
1105 when GT
=> return GT
;
1106 when GE
=> return GE
;
1107 when EQ
=> return GE
;
1108 when others => null;
1111 case Compile_Time_Compare
(Type_High_Bound
(Ltyp
), R
,
1113 Assume_Valid
, Rec
=> True)
1115 when LT
=> return LT
;
1116 when LE
=> return LE
;
1117 when EQ
=> return LE
;
1118 when others => null;
1123 -- Next attempt is to see if we have an entity compared with a
1124 -- compile time known value, where there is a current value
1125 -- conditional for the entity which can tell us the result.
1129 -- Entity variable (left operand)
1132 -- Value (right operand)
1135 -- If False, we have reversed the operands
1138 -- Comparison operator kind from Get_Current_Value_Condition call
1141 -- Value from Get_Current_Value_Condition call
1146 Result
: Compare_Result
;
1147 -- Known result before inversion
1150 if Is_Entity_Name
(L
)
1151 and then Compile_Time_Known_Value
(R
)
1154 Val
:= Expr_Value
(R
);
1157 elsif Is_Entity_Name
(R
)
1158 and then Compile_Time_Known_Value
(L
)
1161 Val
:= Expr_Value
(L
);
1164 -- That was the last chance at finding a compile time result
1170 Get_Current_Value_Condition
(Var
, Op
, Opn
);
1172 -- That was the last chance, so if we got nothing return
1178 Opv
:= Expr_Value
(Opn
);
1180 -- We got a comparison, so we might have something interesting
1182 -- Convert LE to LT and GE to GT, just so we have fewer cases
1184 if Op
= N_Op_Le
then
1188 elsif Op
= N_Op_Ge
then
1193 -- Deal with equality case
1195 if Op
= N_Op_Eq
then
1198 elsif Opv
< Val
then
1204 -- Deal with inequality case
1206 elsif Op
= N_Op_Ne
then
1213 -- Deal with greater than case
1215 elsif Op
= N_Op_Gt
then
1218 elsif Opv
= Val
- 1 then
1224 -- Deal with less than case
1226 else pragma Assert
(Op
= N_Op_Lt
);
1229 elsif Opv
= Val
+ 1 then
1236 -- Deal with inverting result
1240 when GT
=> return LT
;
1241 when GE
=> return LE
;
1242 when LT
=> return GT
;
1243 when LE
=> return GE
;
1244 when others => return Result
;
1251 end Compile_Time_Compare
;
1253 -------------------------------
1254 -- Compile_Time_Known_Bounds --
1255 -------------------------------
1257 function Compile_Time_Known_Bounds
(T
: Entity_Id
) return Boolean is
1262 if T
= Any_Composite
or else not Is_Array_Type
(T
) then
1266 Indx
:= First_Index
(T
);
1267 while Present
(Indx
) loop
1268 Typ
:= Underlying_Type
(Etype
(Indx
));
1270 -- Never look at junk bounds of a generic type
1272 if Is_Generic_Type
(Typ
) then
1276 -- Otherwise check bounds for compile time known
1278 if not Compile_Time_Known_Value
(Type_Low_Bound
(Typ
)) then
1280 elsif not Compile_Time_Known_Value
(Type_High_Bound
(Typ
)) then
1288 end Compile_Time_Known_Bounds
;
1290 ------------------------------
1291 -- Compile_Time_Known_Value --
1292 ------------------------------
1294 function Compile_Time_Known_Value
(Op
: Node_Id
) return Boolean is
1295 K
: constant Node_Kind
:= Nkind
(Op
);
1296 CV_Ent
: CV_Entry
renames CV_Cache
(Nat
(Op
) mod CV_Cache_Size
);
1299 -- Never known at compile time if bad type or raises constraint error
1300 -- or empty (latter case occurs only as a result of a previous error).
1303 Check_Error_Detected
;
1307 or else Etype
(Op
) = Any_Type
1308 or else Raises_Constraint_Error
(Op
)
1313 -- If we have an entity name, then see if it is the name of a constant
1314 -- and if so, test the corresponding constant value, or the name of
1315 -- an enumeration literal, which is always a constant.
1317 if Present
(Etype
(Op
)) and then Is_Entity_Name
(Op
) then
1319 E
: constant Entity_Id
:= Entity
(Op
);
1323 -- Never known at compile time if it is a packed array value.
1324 -- We might want to try to evaluate these at compile time one
1325 -- day, but we do not make that attempt now.
1327 if Is_Packed_Array_Type
(Etype
(Op
)) then
1331 if Ekind
(E
) = E_Enumeration_Literal
then
1334 elsif Ekind
(E
) = E_Constant
then
1335 V
:= Constant_Value
(E
);
1336 return Present
(V
) and then Compile_Time_Known_Value
(V
);
1340 -- We have a value, see if it is compile time known
1343 -- Integer literals are worth storing in the cache
1345 if K
= N_Integer_Literal
then
1347 CV_Ent
.V
:= Intval
(Op
);
1350 -- Other literals and NULL are known at compile time
1353 K
= N_Character_Literal
1357 K
= N_String_Literal
1363 -- Any reference to Null_Parameter is known at compile time. No
1364 -- other attribute references (that have not already been folded)
1365 -- are known at compile time.
1367 elsif K
= N_Attribute_Reference
then
1368 return Attribute_Name
(Op
) = Name_Null_Parameter
;
1372 -- If we fall through, not known at compile time
1376 -- If we get an exception while trying to do this test, then some error
1377 -- has occurred, and we simply say that the value is not known after all
1382 end Compile_Time_Known_Value
;
1384 --------------------------------------
1385 -- Compile_Time_Known_Value_Or_Aggr --
1386 --------------------------------------
1388 function Compile_Time_Known_Value_Or_Aggr
(Op
: Node_Id
) return Boolean is
1390 -- If we have an entity name, then see if it is the name of a constant
1391 -- and if so, test the corresponding constant value, or the name of
1392 -- an enumeration literal, which is always a constant.
1394 if Is_Entity_Name
(Op
) then
1396 E
: constant Entity_Id
:= Entity
(Op
);
1400 if Ekind
(E
) = E_Enumeration_Literal
then
1403 elsif Ekind
(E
) /= E_Constant
then
1407 V
:= Constant_Value
(E
);
1409 and then Compile_Time_Known_Value_Or_Aggr
(V
);
1413 -- We have a value, see if it is compile time known
1416 if Compile_Time_Known_Value
(Op
) then
1419 elsif Nkind
(Op
) = N_Aggregate
then
1421 if Present
(Expressions
(Op
)) then
1426 Expr
:= First
(Expressions
(Op
));
1427 while Present
(Expr
) loop
1428 if not Compile_Time_Known_Value_Or_Aggr
(Expr
) then
1437 if Present
(Component_Associations
(Op
)) then
1442 Cass
:= First
(Component_Associations
(Op
));
1443 while Present
(Cass
) loop
1445 Compile_Time_Known_Value_Or_Aggr
(Expression
(Cass
))
1457 -- All other types of values are not known at compile time
1464 end Compile_Time_Known_Value_Or_Aggr
;
1466 ---------------------------------------
1467 -- CRT_Safe_Compile_Time_Known_Value --
1468 ---------------------------------------
1470 function CRT_Safe_Compile_Time_Known_Value
(Op
: Node_Id
) return Boolean is
1472 if (Configurable_Run_Time_Mode
or No_Run_Time_Mode
)
1473 and then not Is_OK_Static_Expression
(Op
)
1477 return Compile_Time_Known_Value
(Op
);
1479 end CRT_Safe_Compile_Time_Known_Value
;
1485 -- This is only called for actuals of functions that are not predefined
1486 -- operators (which have already been rewritten as operators at this
1487 -- stage), so the call can never be folded, and all that needs doing for
1488 -- the actual is to do the check for a non-static context.
1490 procedure Eval_Actual
(N
: Node_Id
) is
1492 Check_Non_Static_Context
(N
);
1495 --------------------
1496 -- Eval_Allocator --
1497 --------------------
1499 -- Allocators are never static, so all we have to do is to do the
1500 -- check for a non-static context if an expression is present.
1502 procedure Eval_Allocator
(N
: Node_Id
) is
1503 Expr
: constant Node_Id
:= Expression
(N
);
1506 if Nkind
(Expr
) = N_Qualified_Expression
then
1507 Check_Non_Static_Context
(Expression
(Expr
));
1511 ------------------------
1512 -- Eval_Arithmetic_Op --
1513 ------------------------
1515 -- Arithmetic operations are static functions, so the result is static
1516 -- if both operands are static (RM 4.9(7), 4.9(20)).
1518 procedure Eval_Arithmetic_Op
(N
: Node_Id
) is
1519 Left
: constant Node_Id
:= Left_Opnd
(N
);
1520 Right
: constant Node_Id
:= Right_Opnd
(N
);
1521 Ltype
: constant Entity_Id
:= Etype
(Left
);
1522 Rtype
: constant Entity_Id
:= Etype
(Right
);
1523 Otype
: Entity_Id
:= Empty
;
1528 -- If not foldable we are done
1530 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
1536 -- Otherwise attempt to fold
1538 if Is_Universal_Numeric_Type
(Etype
(Left
))
1540 Is_Universal_Numeric_Type
(Etype
(Right
))
1542 Otype
:= Find_Universal_Operator_Type
(N
);
1545 -- Fold for cases where both operands are of integer type
1547 if Is_Integer_Type
(Ltype
) and then Is_Integer_Type
(Rtype
) then
1549 Left_Int
: constant Uint
:= Expr_Value
(Left
);
1550 Right_Int
: constant Uint
:= Expr_Value
(Right
);
1557 Result
:= Left_Int
+ Right_Int
;
1559 when N_Op_Subtract
=>
1560 Result
:= Left_Int
- Right_Int
;
1562 when N_Op_Multiply
=>
1565 (Num_Bits
(Left_Int
) + Num_Bits
(Right_Int
)))
1567 Result
:= Left_Int
* Right_Int
;
1574 -- The exception Constraint_Error is raised by integer
1575 -- division, rem and mod if the right operand is zero.
1577 if Right_Int
= 0 then
1578 Apply_Compile_Time_Constraint_Error
1579 (N
, "division by zero",
1585 Result
:= Left_Int
/ Right_Int
;
1590 -- The exception Constraint_Error is raised by integer
1591 -- division, rem and mod if the right operand is zero.
1593 if Right_Int
= 0 then
1594 Apply_Compile_Time_Constraint_Error
1595 (N
, "mod with zero divisor",
1600 Result
:= Left_Int
mod Right_Int
;
1605 -- The exception Constraint_Error is raised by integer
1606 -- division, rem and mod if the right operand is zero.
1608 if Right_Int
= 0 then
1609 Apply_Compile_Time_Constraint_Error
1610 (N
, "rem with zero divisor",
1616 Result
:= Left_Int
rem Right_Int
;
1620 raise Program_Error
;
1623 -- Adjust the result by the modulus if the type is a modular type
1625 if Is_Modular_Integer_Type
(Ltype
) then
1626 Result
:= Result
mod Modulus
(Ltype
);
1628 -- For a signed integer type, check non-static overflow
1630 elsif (not Stat
) and then Is_Signed_Integer_Type
(Ltype
) then
1632 BT
: constant Entity_Id
:= Base_Type
(Ltype
);
1633 Lo
: constant Uint
:= Expr_Value
(Type_Low_Bound
(BT
));
1634 Hi
: constant Uint
:= Expr_Value
(Type_High_Bound
(BT
));
1636 if Result
< Lo
or else Result
> Hi
then
1637 Apply_Compile_Time_Constraint_Error
1638 (N
, "value not in range of }??",
1639 CE_Overflow_Check_Failed
,
1646 -- If we get here we can fold the result
1648 Fold_Uint
(N
, Result
, Stat
);
1651 -- Cases where at least one operand is a real. We handle the cases of
1652 -- both reals, or mixed/real integer cases (the latter happen only for
1653 -- divide and multiply, and the result is always real).
1655 elsif Is_Real_Type
(Ltype
) or else Is_Real_Type
(Rtype
) then
1662 if Is_Real_Type
(Ltype
) then
1663 Left_Real
:= Expr_Value_R
(Left
);
1665 Left_Real
:= UR_From_Uint
(Expr_Value
(Left
));
1668 if Is_Real_Type
(Rtype
) then
1669 Right_Real
:= Expr_Value_R
(Right
);
1671 Right_Real
:= UR_From_Uint
(Expr_Value
(Right
));
1674 if Nkind
(N
) = N_Op_Add
then
1675 Result
:= Left_Real
+ Right_Real
;
1677 elsif Nkind
(N
) = N_Op_Subtract
then
1678 Result
:= Left_Real
- Right_Real
;
1680 elsif Nkind
(N
) = N_Op_Multiply
then
1681 Result
:= Left_Real
* Right_Real
;
1683 else pragma Assert
(Nkind
(N
) = N_Op_Divide
);
1684 if UR_Is_Zero
(Right_Real
) then
1685 Apply_Compile_Time_Constraint_Error
1686 (N
, "division by zero", CE_Divide_By_Zero
);
1690 Result
:= Left_Real
/ Right_Real
;
1693 Fold_Ureal
(N
, Result
, Stat
);
1697 -- If the operator was resolved to a specific type, make sure that type
1698 -- is frozen even if the expression is folded into a literal (which has
1699 -- a universal type).
1701 if Present
(Otype
) then
1702 Freeze_Before
(N
, Otype
);
1704 end Eval_Arithmetic_Op
;
1706 ----------------------------
1707 -- Eval_Character_Literal --
1708 ----------------------------
1710 -- Nothing to be done
1712 procedure Eval_Character_Literal
(N
: Node_Id
) is
1713 pragma Warnings
(Off
, N
);
1716 end Eval_Character_Literal
;
1722 -- Static function calls are either calls to predefined operators
1723 -- with static arguments, or calls to functions that rename a literal.
1724 -- Only the latter case is handled here, predefined operators are
1725 -- constant-folded elsewhere.
1727 -- If the function is itself inherited (see 7423-001) the literal of
1728 -- the parent type must be explicitly converted to the return type
1731 procedure Eval_Call
(N
: Node_Id
) is
1732 Loc
: constant Source_Ptr
:= Sloc
(N
);
1733 Typ
: constant Entity_Id
:= Etype
(N
);
1737 if Nkind
(N
) = N_Function_Call
1738 and then No
(Parameter_Associations
(N
))
1739 and then Is_Entity_Name
(Name
(N
))
1740 and then Present
(Alias
(Entity
(Name
(N
))))
1741 and then Is_Enumeration_Type
(Base_Type
(Typ
))
1743 Lit
:= Ultimate_Alias
(Entity
(Name
(N
)));
1745 if Ekind
(Lit
) = E_Enumeration_Literal
then
1746 if Base_Type
(Etype
(Lit
)) /= Base_Type
(Typ
) then
1748 (N
, Convert_To
(Typ
, New_Occurrence_Of
(Lit
, Loc
)));
1750 Rewrite
(N
, New_Occurrence_Of
(Lit
, Loc
));
1758 --------------------------
1759 -- Eval_Case_Expression --
1760 --------------------------
1762 -- A conditional expression is static if all its conditions and dependent
1763 -- expressions are static.
1765 procedure Eval_Case_Expression
(N
: Node_Id
) is
1768 Is_Static
: Boolean;
1776 if Is_Static_Expression
(Expression
(N
)) then
1777 Val
:= Expr_Value
(Expression
(N
));
1780 Check_Non_Static_Context
(Expression
(N
));
1784 Alt
:= First
(Alternatives
(N
));
1786 Search
: while Present
(Alt
) loop
1788 or else not Is_Static_Expression
(Expression
(Alt
))
1790 Check_Non_Static_Context
(Expression
(Alt
));
1794 Choice
:= First
(Discrete_Choices
(Alt
));
1795 while Present
(Choice
) loop
1796 if Nkind
(Choice
) = N_Others_Choice
then
1797 Result
:= Expression
(Alt
);
1800 elsif Expr_Value
(Choice
) = Val
then
1801 Result
:= Expression
(Alt
);
1814 Rewrite
(N
, Relocate_Node
(Result
));
1817 Set_Is_Static_Expression
(N
, False);
1819 end Eval_Case_Expression
;
1821 ------------------------
1822 -- Eval_Concatenation --
1823 ------------------------
1825 -- Concatenation is a static function, so the result is static if both
1826 -- operands are static (RM 4.9(7), 4.9(21)).
1828 procedure Eval_Concatenation
(N
: Node_Id
) is
1829 Left
: constant Node_Id
:= Left_Opnd
(N
);
1830 Right
: constant Node_Id
:= Right_Opnd
(N
);
1831 C_Typ
: constant Entity_Id
:= Root_Type
(Component_Type
(Etype
(N
)));
1836 -- Concatenation is never static in Ada 83, so if Ada 83 check operand
1837 -- non-static context.
1839 if Ada_Version
= Ada_83
1840 and then Comes_From_Source
(N
)
1842 Check_Non_Static_Context
(Left
);
1843 Check_Non_Static_Context
(Right
);
1847 -- If not foldable we are done. In principle concatenation that yields
1848 -- any string type is static (i.e. an array type of character types).
1849 -- However, character types can include enumeration literals, and
1850 -- concatenation in that case cannot be described by a literal, so we
1851 -- only consider the operation static if the result is an array of
1852 -- (a descendant of) a predefined character type.
1854 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
1856 if not (Is_Standard_Character_Type
(C_Typ
) and then Fold
) then
1857 Set_Is_Static_Expression
(N
, False);
1861 -- Compile time string concatenation
1863 -- ??? Note that operands that are aggregates can be marked as static,
1864 -- so we should attempt at a later stage to fold concatenations with
1868 Left_Str
: constant Node_Id
:= Get_String_Val
(Left
);
1870 Right_Str
: constant Node_Id
:= Get_String_Val
(Right
);
1871 Folded_Val
: String_Id
;
1874 -- Establish new string literal, and store left operand. We make
1875 -- sure to use the special Start_String that takes an operand if
1876 -- the left operand is a string literal. Since this is optimized
1877 -- in the case where that is the most recently created string
1878 -- literal, we ensure efficient time/space behavior for the
1879 -- case of a concatenation of a series of string literals.
1881 if Nkind
(Left_Str
) = N_String_Literal
then
1882 Left_Len
:= String_Length
(Strval
(Left_Str
));
1884 -- If the left operand is the empty string, and the right operand
1885 -- is a string literal (the case of "" & "..."), the result is the
1886 -- value of the right operand. This optimization is important when
1887 -- Is_Folded_In_Parser, to avoid copying an enormous right
1890 if Left_Len
= 0 and then Nkind
(Right_Str
) = N_String_Literal
then
1891 Folded_Val
:= Strval
(Right_Str
);
1893 Start_String
(Strval
(Left_Str
));
1898 Store_String_Char
(UI_To_CC
(Char_Literal_Value
(Left_Str
)));
1902 -- Now append the characters of the right operand, unless we
1903 -- optimized the "" & "..." case above.
1905 if Nkind
(Right_Str
) = N_String_Literal
then
1906 if Left_Len
/= 0 then
1907 Store_String_Chars
(Strval
(Right_Str
));
1908 Folded_Val
:= End_String
;
1911 Store_String_Char
(UI_To_CC
(Char_Literal_Value
(Right_Str
)));
1912 Folded_Val
:= End_String
;
1915 Set_Is_Static_Expression
(N
, Stat
);
1917 -- If left operand is the empty string, the result is the
1918 -- right operand, including its bounds if anomalous.
1921 and then Is_Array_Type
(Etype
(Right
))
1922 and then Etype
(Right
) /= Any_String
1924 Set_Etype
(N
, Etype
(Right
));
1927 Fold_Str
(N
, Folded_Val
, Static
=> Stat
);
1929 end Eval_Concatenation
;
1931 ----------------------
1932 -- Eval_Entity_Name --
1933 ----------------------
1935 -- This procedure is used for identifiers and expanded names other than
1936 -- named numbers (see Eval_Named_Integer, Eval_Named_Real. These are
1937 -- static if they denote a static constant (RM 4.9(6)) or if the name
1938 -- denotes an enumeration literal (RM 4.9(22)).
1940 procedure Eval_Entity_Name
(N
: Node_Id
) is
1941 Def_Id
: constant Entity_Id
:= Entity
(N
);
1945 -- Enumeration literals are always considered to be constants
1946 -- and cannot raise constraint error (RM 4.9(22)).
1948 if Ekind
(Def_Id
) = E_Enumeration_Literal
then
1949 Set_Is_Static_Expression
(N
);
1952 -- A name is static if it denotes a static constant (RM 4.9(5)), and
1953 -- we also copy Raise_Constraint_Error. Notice that even if non-static,
1954 -- it does not violate 10.2.1(8) here, since this is not a variable.
1956 elsif Ekind
(Def_Id
) = E_Constant
then
1958 -- Deferred constants must always be treated as nonstatic
1959 -- outside the scope of their full view.
1961 if Present
(Full_View
(Def_Id
))
1962 and then not In_Open_Scopes
(Scope
(Def_Id
))
1966 Val
:= Constant_Value
(Def_Id
);
1969 if Present
(Val
) then
1970 Set_Is_Static_Expression
1971 (N
, Is_Static_Expression
(Val
)
1972 and then Is_Static_Subtype
(Etype
(Def_Id
)));
1973 Set_Raises_Constraint_Error
(N
, Raises_Constraint_Error
(Val
));
1975 if not Is_Static_Expression
(N
)
1976 and then not Is_Generic_Type
(Etype
(N
))
1978 Validate_Static_Object_Name
(N
);
1985 -- Fall through if the name is not static
1987 Validate_Static_Object_Name
(N
);
1988 end Eval_Entity_Name
;
1990 ------------------------
1991 -- Eval_If_Expression --
1992 ------------------------
1994 -- We can fold to a static expression if the condition and both dependent
1995 -- expressions are static. Otherwise, the only required processing is to do
1996 -- the check for non-static context for the then and else expressions.
1998 procedure Eval_If_Expression
(N
: Node_Id
) is
1999 Condition
: constant Node_Id
:= First
(Expressions
(N
));
2000 Then_Expr
: constant Node_Id
:= Next
(Condition
);
2001 Else_Expr
: constant Node_Id
:= Next
(Then_Expr
);
2003 Non_Result
: Node_Id
;
2005 Rstat
: constant Boolean :=
2006 Is_Static_Expression
(Condition
)
2008 Is_Static_Expression
(Then_Expr
)
2010 Is_Static_Expression
(Else_Expr
);
2013 -- If any operand is Any_Type, just propagate to result and do not try
2014 -- to fold, this prevents cascaded errors.
2016 if Etype
(Condition
) = Any_Type
or else
2017 Etype
(Then_Expr
) = Any_Type
or else
2018 Etype
(Else_Expr
) = Any_Type
2020 Set_Etype
(N
, Any_Type
);
2021 Set_Is_Static_Expression
(N
, False);
2024 -- Static case where we can fold. Note that we don't try to fold cases
2025 -- where the condition is known at compile time, but the result is
2026 -- non-static. This avoids possible cases of infinite recursion where
2027 -- the expander puts in a redundant test and we remove it. Instead we
2028 -- deal with these cases in the expander.
2032 -- Select result operand
2034 if Is_True
(Expr_Value
(Condition
)) then
2035 Result
:= Then_Expr
;
2036 Non_Result
:= Else_Expr
;
2038 Result
:= Else_Expr
;
2039 Non_Result
:= Then_Expr
;
2042 -- Note that it does not matter if the non-result operand raises a
2043 -- Constraint_Error, but if the result raises constraint error then
2044 -- we replace the node with a raise constraint error. This will
2045 -- properly propagate Raises_Constraint_Error since this flag is
2048 if Raises_Constraint_Error
(Result
) then
2049 Rewrite_In_Raise_CE
(N
, Result
);
2050 Check_Non_Static_Context
(Non_Result
);
2052 -- Otherwise the result operand replaces the original node
2055 Rewrite
(N
, Relocate_Node
(Result
));
2058 -- Case of condition not known at compile time
2061 Check_Non_Static_Context
(Condition
);
2062 Check_Non_Static_Context
(Then_Expr
);
2063 Check_Non_Static_Context
(Else_Expr
);
2066 Set_Is_Static_Expression
(N
, Rstat
);
2067 end Eval_If_Expression
;
2069 ----------------------------
2070 -- Eval_Indexed_Component --
2071 ----------------------------
2073 -- Indexed components are never static, so we need to perform the check
2074 -- for non-static context on the index values. Then, we check if the
2075 -- value can be obtained at compile time, even though it is non-static.
2077 procedure Eval_Indexed_Component
(N
: Node_Id
) is
2081 -- Check for non-static context on index values
2083 Expr
:= First
(Expressions
(N
));
2084 while Present
(Expr
) loop
2085 Check_Non_Static_Context
(Expr
);
2089 -- If the indexed component appears in an object renaming declaration
2090 -- then we do not want to try to evaluate it, since in this case we
2091 -- need the identity of the array element.
2093 if Nkind
(Parent
(N
)) = N_Object_Renaming_Declaration
then
2096 -- Similarly if the indexed component appears as the prefix of an
2097 -- attribute we don't want to evaluate it, because at least for
2098 -- some cases of attributes we need the identify (e.g. Access, Size)
2100 elsif Nkind
(Parent
(N
)) = N_Attribute_Reference
then
2104 -- Note: there are other cases, such as the left side of an assignment,
2105 -- or an OUT parameter for a call, where the replacement results in the
2106 -- illegal use of a constant, But these cases are illegal in the first
2107 -- place, so the replacement, though silly, is harmless.
2109 -- Now see if this is a constant array reference
2111 if List_Length
(Expressions
(N
)) = 1
2112 and then Is_Entity_Name
(Prefix
(N
))
2113 and then Ekind
(Entity
(Prefix
(N
))) = E_Constant
2114 and then Present
(Constant_Value
(Entity
(Prefix
(N
))))
2117 Loc
: constant Source_Ptr
:= Sloc
(N
);
2118 Arr
: constant Node_Id
:= Constant_Value
(Entity
(Prefix
(N
)));
2119 Sub
: constant Node_Id
:= First
(Expressions
(N
));
2125 -- Linear one's origin subscript value for array reference
2128 -- Lower bound of the first array index
2131 -- Value from constant array
2134 Atyp
:= Etype
(Arr
);
2136 if Is_Access_Type
(Atyp
) then
2137 Atyp
:= Designated_Type
(Atyp
);
2140 -- If we have an array type (we should have but perhaps there are
2141 -- error cases where this is not the case), then see if we can do
2142 -- a constant evaluation of the array reference.
2144 if Is_Array_Type
(Atyp
) and then Atyp
/= Any_Composite
then
2145 if Ekind
(Atyp
) = E_String_Literal_Subtype
then
2146 Lbd
:= String_Literal_Low_Bound
(Atyp
);
2148 Lbd
:= Type_Low_Bound
(Etype
(First_Index
(Atyp
)));
2151 if Compile_Time_Known_Value
(Sub
)
2152 and then Nkind
(Arr
) = N_Aggregate
2153 and then Compile_Time_Known_Value
(Lbd
)
2154 and then Is_Discrete_Type
(Component_Type
(Atyp
))
2156 Lin
:= UI_To_Int
(Expr_Value
(Sub
) - Expr_Value
(Lbd
)) + 1;
2158 if List_Length
(Expressions
(Arr
)) >= Lin
then
2159 Elm
:= Pick
(Expressions
(Arr
), Lin
);
2161 -- If the resulting expression is compile time known,
2162 -- then we can rewrite the indexed component with this
2163 -- value, being sure to mark the result as non-static.
2164 -- We also reset the Sloc, in case this generates an
2165 -- error later on (e.g. 136'Access).
2167 if Compile_Time_Known_Value
(Elm
) then
2168 Rewrite
(N
, Duplicate_Subexpr_No_Checks
(Elm
));
2169 Set_Is_Static_Expression
(N
, False);
2174 -- We can also constant-fold if the prefix is a string literal.
2175 -- This will be useful in an instantiation or an inlining.
2177 elsif Compile_Time_Known_Value
(Sub
)
2178 and then Nkind
(Arr
) = N_String_Literal
2179 and then Compile_Time_Known_Value
(Lbd
)
2180 and then Expr_Value
(Lbd
) = 1
2181 and then Expr_Value
(Sub
) <=
2182 String_Literal_Length
(Etype
(Arr
))
2185 C
: constant Char_Code
:=
2186 Get_String_Char
(Strval
(Arr
),
2187 UI_To_Int
(Expr_Value
(Sub
)));
2189 Set_Character_Literal_Name
(C
);
2192 Make_Character_Literal
(Loc
,
2194 Char_Literal_Value
=> UI_From_CC
(C
));
2195 Set_Etype
(Elm
, Component_Type
(Atyp
));
2196 Rewrite
(N
, Duplicate_Subexpr_No_Checks
(Elm
));
2197 Set_Is_Static_Expression
(N
, False);
2203 end Eval_Indexed_Component
;
2205 --------------------------
2206 -- Eval_Integer_Literal --
2207 --------------------------
2209 -- Numeric literals are static (RM 4.9(1)), and have already been marked
2210 -- as static by the analyzer. The reason we did it that early is to allow
2211 -- the possibility of turning off the Is_Static_Expression flag after
2212 -- analysis, but before resolution, when integer literals are generated in
2213 -- the expander that do not correspond to static expressions.
2215 procedure Eval_Integer_Literal
(N
: Node_Id
) is
2216 T
: constant Entity_Id
:= Etype
(N
);
2218 function In_Any_Integer_Context
return Boolean;
2219 -- If the literal is resolved with a specific type in a context where
2220 -- the expected type is Any_Integer, there are no range checks on the
2221 -- literal. By the time the literal is evaluated, it carries the type
2222 -- imposed by the enclosing expression, and we must recover the context
2223 -- to determine that Any_Integer is meant.
2225 ----------------------------
2226 -- In_Any_Integer_Context --
2227 ----------------------------
2229 function In_Any_Integer_Context
return Boolean is
2230 Par
: constant Node_Id
:= Parent
(N
);
2231 K
: constant Node_Kind
:= Nkind
(Par
);
2234 -- Any_Integer also appears in digits specifications for real types,
2235 -- but those have bounds smaller that those of any integer base type,
2236 -- so we can safely ignore these cases.
2238 return K
= N_Number_Declaration
2239 or else K
= N_Attribute_Reference
2240 or else K
= N_Attribute_Definition_Clause
2241 or else K
= N_Modular_Type_Definition
2242 or else K
= N_Signed_Integer_Type_Definition
;
2243 end In_Any_Integer_Context
;
2245 -- Start of processing for Eval_Integer_Literal
2249 -- If the literal appears in a non-expression context, then it is
2250 -- certainly appearing in a non-static context, so check it. This is
2251 -- actually a redundant check, since Check_Non_Static_Context would
2252 -- check it, but it seems worth while avoiding the call.
2254 if Nkind
(Parent
(N
)) not in N_Subexpr
2255 and then not In_Any_Integer_Context
2257 Check_Non_Static_Context
(N
);
2260 -- Modular integer literals must be in their base range
2262 if Is_Modular_Integer_Type
(T
)
2263 and then Is_Out_Of_Range
(N
, Base_Type
(T
), Assume_Valid
=> True)
2267 end Eval_Integer_Literal
;
2269 ---------------------
2270 -- Eval_Logical_Op --
2271 ---------------------
2273 -- Logical operations are static functions, so the result is potentially
2274 -- static if both operands are potentially static (RM 4.9(7), 4.9(20)).
2276 procedure Eval_Logical_Op
(N
: Node_Id
) is
2277 Left
: constant Node_Id
:= Left_Opnd
(N
);
2278 Right
: constant Node_Id
:= Right_Opnd
(N
);
2283 -- If not foldable we are done
2285 Test_Expression_Is_Foldable
(N
, Left
, Right
, Stat
, Fold
);
2291 -- Compile time evaluation of logical operation
2294 Left_Int
: constant Uint
:= Expr_Value
(Left
);
2295 Right_Int
: constant Uint
:= Expr_Value
(Right
);
2298 -- VMS includes bitwise operations on signed types
2300 if Is_Modular_Integer_Type
(Etype
(N
))
2301 or else Is_VMS_Operator
(Entity
(N
))
2304 Left_Bits
: Bits
(0 .. UI_To_Int
(Esize
(Etype
(N
))) - 1);
2305 Right_Bits
: Bits
(0 .. UI_To_Int
(Esize
(Etype
(N
))) - 1);
2308 To_Bits
(Left_Int
, Left_Bits
);
2309 To_Bits
(Right_Int
, Right_Bits
);
2311 -- Note: should really be able to use array ops instead of
2312 -- these loops, but they weren't working at the time ???
2314 if Nkind
(N
) = N_Op_And
then
2315 for J
in Left_Bits
'Range loop
2316 Left_Bits
(J
) := Left_Bits
(J
) and Right_Bits
(J
);
2319 elsif Nkind
(N
) = N_Op_Or
then
2320 for J
in Left_Bits
'Range loop
2321 Left_Bits
(J
) := Left_Bits
(J
) or Right_Bits
(J
);
2325 pragma Assert
(Nkind
(N
) = N_Op_Xor
);
2327 for J
in Left_Bits
'Range loop
2328 Left_Bits
(J
) := Left_Bits
(J
) xor Right_Bits
(J
);
2332 Fold_Uint
(N
, From_Bits
(Left_Bits
, Etype
(N
)), Stat
);
2336 pragma Assert
(Is_Boolean_Type
(Etype
(N
)));
2338 if Nkind
(N
) = N_Op_And
then
2340 Test
(Is_True
(Left_Int
) and then Is_True
(Right_Int
)), Stat
);
2342 elsif Nkind
(N
) = N_Op_Or
then
2344 Test
(Is_True
(Left_Int
) or else Is_True
(Right_Int
)), Stat
);
2347 pragma Assert
(Nkind
(N
) = N_Op_Xor
);
2349 Test
(Is_True
(Left_Int
) xor Is_True
(Right_Int
)), Stat
);
2353 end Eval_Logical_Op
;
2355 ------------------------
2356 -- Eval_Membership_Op --
2357 ------------------------
2359 -- A membership test is potentially static if the expression is static, and
2360 -- the range is a potentially static range, or is a subtype mark denoting a
2361 -- static subtype (RM 4.9(12)).
2363 procedure Eval_Membership_Op
(N
: Node_Id
) is
2364 Left
: constant Node_Id
:= Left_Opnd
(N
);
2365 Right
: constant Node_Id
:= Right_Opnd
(N
);
2374 -- Ignore if error in either operand, except to make sure that Any_Type
2375 -- is properly propagated to avoid junk cascaded errors.
2377 if Etype
(Left
) = Any_Type
or else Etype
(Right
) = Any_Type
then
2378 Set_Etype
(N
, Any_Type
);
2382 -- Ignore if types involved have predicates
2384 if Present
(Predicate_Function
(Etype
(Left
)))
2386 Present
(Predicate_Function
(Etype
(Right
)))
2391 -- Case of right operand is a subtype name
2393 if Is_Entity_Name
(Right
) then
2394 Def_Id
:= Entity
(Right
);
2396 if (Is_Scalar_Type
(Def_Id
) or else Is_String_Type
(Def_Id
))
2397 and then Is_OK_Static_Subtype
(Def_Id
)
2399 Test_Expression_Is_Foldable
(N
, Left
, Stat
, Fold
);
2401 if not Fold
or else not Stat
then
2405 Check_Non_Static_Context
(Left
);
2409 -- For string membership tests we will check the length further on
2411 if not Is_String_Type
(Def_Id
) then
2412 Lo
:= Type_Low_Bound
(Def_Id
);
2413 Hi
:= Type_High_Bound
(Def_Id
);
2420 -- Case of right operand is a range
2423 if Is_Static_Range
(Right
) then
2424 Test_Expression_Is_Foldable
(N
, Left
, Stat
, Fold
);
2426 if not Fold
or else not Stat
then
2429 -- If one bound of range raises CE, then don't try to fold
2431 elsif not Is_OK_Static_Range
(Right
) then
2432 Check_Non_Static_Context
(Left
);
2437 Check_Non_Static_Context
(Left
);
2441 -- Here we know range is an OK static range
2443 Lo
:= Low_Bound
(Right
);
2444 Hi
:= High_Bound
(Right
);
2447 -- For strings we check that the length of the string expression is
2448 -- compatible with the string subtype if the subtype is constrained,
2449 -- or if unconstrained then the test is always true.
2451 if Is_String_Type
(Etype
(Right
)) then
2452 if not Is_Constrained
(Etype
(Right
)) then
2457 Typlen
: constant Uint
:= String_Type_Len
(Etype
(Right
));
2458 Strlen
: constant Uint
:=
2460 (String_Length
(Strval
(Get_String_Val
(Left
))));
2462 Result
:= (Typlen
= Strlen
);
2466 -- Fold the membership test. We know we have a static range and Lo and
2467 -- Hi are set to the expressions for the end points of this range.
2469 elsif Is_Real_Type
(Etype
(Right
)) then
2471 Leftval
: constant Ureal
:= Expr_Value_R
(Left
);
2474 Result
:= Expr_Value_R
(Lo
) <= Leftval
2475 and then Leftval
<= Expr_Value_R
(Hi
);
2480 Leftval
: constant Uint
:= Expr_Value
(Left
);
2483 Result
:= Expr_Value
(Lo
) <= Leftval
2484 and then Leftval
<= Expr_Value
(Hi
);
2488 if Nkind
(N
) = N_Not_In
then
2489 Result
:= not Result
;
2492 Fold_Uint
(N
, Test
(Result
), True);
2494 Warn_On_Known_Condition
(N
);
2495 end Eval_Membership_Op
;
2497 ------------------------
2498 -- Eval_Named_Integer --
2499 ------------------------
2501 procedure Eval_Named_Integer
(N
: Node_Id
) is
2504 Expr_Value
(Expression
(Declaration_Node
(Entity
(N
)))), True);
2505 end Eval_Named_Integer
;
2507 ---------------------
2508 -- Eval_Named_Real --
2509 ---------------------
2511 procedure Eval_Named_Real
(N
: Node_Id
) is
2514 Expr_Value_R
(Expression
(Declaration_Node
(Entity
(N
)))), True);
2515 end Eval_Named_Real
;
2521 -- Exponentiation is a static functions, so the result is potentially
2522 -- static if both operands are potentially static (RM 4.9(7), 4.9(20)).
2524 procedure Eval_Op_Expon
(N
: Node_Id
) is
2525 Left
: constant Node_Id
:= Left_Opnd
(N
);
2526 Right
: constant Node_Id
:= Right_Opnd
(N
);
2531 -- If not foldable we are done
2533 Test_Expression_Is_Foldable
2534 (N
, Left
, Right
, Stat
, Fold
, CRT_Safe
=> True);
2536 -- Return if not foldable
2542 if Configurable_Run_Time_Mode
and not Stat
then
2546 -- Fold exponentiation operation
2549 Right_Int
: constant Uint
:= Expr_Value
(Right
);
2554 if Is_Integer_Type
(Etype
(Left
)) then
2556 Left_Int
: constant Uint
:= Expr_Value
(Left
);
2560 -- Exponentiation of an integer raises Constraint_Error for a
2561 -- negative exponent (RM 4.5.6).
2563 if Right_Int
< 0 then
2564 Apply_Compile_Time_Constraint_Error
2565 (N
, "integer exponent negative",
2566 CE_Range_Check_Failed
,
2571 if OK_Bits
(N
, Num_Bits
(Left_Int
) * Right_Int
) then
2572 Result
:= Left_Int
** Right_Int
;
2577 if Is_Modular_Integer_Type
(Etype
(N
)) then
2578 Result
:= Result
mod Modulus
(Etype
(N
));
2581 Fold_Uint
(N
, Result
, Stat
);
2589 Left_Real
: constant Ureal
:= Expr_Value_R
(Left
);
2592 -- Cannot have a zero base with a negative exponent
2594 if UR_Is_Zero
(Left_Real
) then
2596 if Right_Int
< 0 then
2597 Apply_Compile_Time_Constraint_Error
2598 (N
, "zero ** negative integer",
2599 CE_Range_Check_Failed
,
2603 Fold_Ureal
(N
, Ureal_0
, Stat
);
2607 Fold_Ureal
(N
, Left_Real
** Right_Int
, Stat
);
2618 -- The not operation is a static functions, so the result is potentially
2619 -- static if the operand is potentially static (RM 4.9(7), 4.9(20)).
2621 procedure Eval_Op_Not
(N
: Node_Id
) is
2622 Right
: constant Node_Id
:= Right_Opnd
(N
);
2627 -- If not foldable we are done
2629 Test_Expression_Is_Foldable
(N
, Right
, Stat
, Fold
);
2635 -- Fold not operation
2638 Rint
: constant Uint
:= Expr_Value
(Right
);
2639 Typ
: constant Entity_Id
:= Etype
(N
);
2642 -- Negation is equivalent to subtracting from the modulus minus one.
2643 -- For a binary modulus this is equivalent to the ones-complement of
2644 -- the original value. For non-binary modulus this is an arbitrary
2645 -- but consistent definition.
2647 if Is_Modular_Integer_Type
(Typ
) then
2648 Fold_Uint
(N
, Modulus
(Typ
) - 1 - Rint
, Stat
);
2651 pragma Assert
(Is_Boolean_Type
(Typ
));
2652 Fold_Uint
(N
, Test
(not Is_True
(Rint
)), Stat
);
2655 Set_Is_Static_Expression
(N
, Stat
);
2659 -------------------------------
2660 -- Eval_Qualified_Expression --
2661 -------------------------------
2663 -- A qualified expression is potentially static if its subtype mark denotes
2664 -- a static subtype and its expression is potentially static (RM 4.9 (11)).
2666 procedure Eval_Qualified_Expression
(N
: Node_Id
) is
2667 Operand
: constant Node_Id
:= Expression
(N
);
2668 Target_Type
: constant Entity_Id
:= Entity
(Subtype_Mark
(N
));
2675 -- Can only fold if target is string or scalar and subtype is static.
2676 -- Also, do not fold if our parent is an allocator (this is because the
2677 -- qualified expression is really part of the syntactic structure of an
2678 -- allocator, and we do not want to end up with something that
2679 -- corresponds to "new 1" where the 1 is the result of folding a
2680 -- qualified expression).
2682 if not Is_Static_Subtype
(Target_Type
)
2683 or else Nkind
(Parent
(N
)) = N_Allocator
2685 Check_Non_Static_Context
(Operand
);
2687 -- If operand is known to raise constraint_error, set the flag on the
2688 -- expression so it does not get optimized away.
2690 if Nkind
(Operand
) = N_Raise_Constraint_Error
then
2691 Set_Raises_Constraint_Error
(N
);
2697 -- If not foldable we are done
2699 Test_Expression_Is_Foldable
(N
, Operand
, Stat
, Fold
);
2704 -- Don't try fold if target type has constraint error bounds
2706 elsif not Is_OK_Static_Subtype
(Target_Type
) then
2707 Set_Raises_Constraint_Error
(N
);
2711 -- Here we will fold, save Print_In_Hex indication
2713 Hex
:= Nkind
(Operand
) = N_Integer_Literal
2714 and then Print_In_Hex
(Operand
);
2716 -- Fold the result of qualification
2718 if Is_Discrete_Type
(Target_Type
) then
2719 Fold_Uint
(N
, Expr_Value
(Operand
), Stat
);
2721 -- Preserve Print_In_Hex indication
2723 if Hex
and then Nkind
(N
) = N_Integer_Literal
then
2724 Set_Print_In_Hex
(N
);
2727 elsif Is_Real_Type
(Target_Type
) then
2728 Fold_Ureal
(N
, Expr_Value_R
(Operand
), Stat
);
2731 Fold_Str
(N
, Strval
(Get_String_Val
(Operand
)), Stat
);
2734 Set_Is_Static_Expression
(N
, False);
2736 Check_String_Literal_Length
(N
, Target_Type
);
2742 -- The expression may be foldable but not static
2744 Set_Is_Static_Expression
(N
, Stat
);
2746 if Is_Out_Of_Range
(N
, Etype
(N
), Assume_Valid
=> True) then
2749 end Eval_Qualified_Expression
;
2751 -----------------------
2752 -- Eval_Real_Literal --
2753 -----------------------
2755 -- Numeric literals are static (RM 4.9(1)), and have already been marked
2756 -- as static by the analyzer. The reason we did it that early is to allow
2757 -- the possibility of turning off the Is_Static_Expression flag after
2758 -- analysis, but before resolution, when integer literals are generated
2759 -- in the expander that do not correspond to static expressions.
2761 procedure Eval_Real_Literal
(N
: Node_Id
) is
2762 PK
: constant Node_Kind
:= Nkind
(Parent
(N
));
2765 -- If the literal appears in a non-expression context and not as part of
2766 -- a number declaration, then it is appearing in a non-static context,
2769 if PK
not in N_Subexpr
and then PK
/= N_Number_Declaration
then
2770 Check_Non_Static_Context
(N
);
2772 end Eval_Real_Literal
;
2774 ------------------------
2775 -- Eval_Relational_Op --
2776 ------------------------
2778 -- Relational operations are static functions, so the result is static if
2779 -- both operands are static (RM 4.9(7), 4.9(20)), except that for strings,
2780 -- the result is never static, even if the operands are.
2782 procedure Eval_Relational_Op
(N
: Node_Id
) is
2783 Left
: constant Node_Id
:= Left_Opnd
(N
);
2784 Right
: constant Node_Id
:= Right_Opnd
(N
);
2785 Typ
: constant Entity_Id
:= Etype
(Left
);
2786 Otype
: Entity_Id
:= Empty
;
2790 -- One special case to deal with first. If we can tell that the result
2791 -- will be false because the lengths of one or more index subtypes are
2792 -- compile time known and different, then we can replace the entire
2793 -- result by False. We only do this for one dimensional arrays, because
2794 -- the case of multi-dimensional arrays is rare and too much trouble. If
2795 -- one of the operands is an illegal aggregate, its type might still be
2796 -- an arbitrary composite type, so nothing to do.
2798 if Is_Array_Type
(Typ
)
2799 and then Typ
/= Any_Composite
2800 and then Number_Dimensions
(Typ
) = 1
2801 and then (Nkind
(N
) = N_Op_Eq
or else Nkind
(N
) = N_Op_Ne
)
2803 if Raises_Constraint_Error
(Left
)
2804 or else Raises_Constraint_Error
(Right
)
2809 -- OK, we have the case where we may be able to do this fold
2811 Length_Mismatch
: declare
2812 procedure Get_Static_Length
(Op
: Node_Id
; Len
: out Uint
);
2813 -- If Op is an expression for a constrained array with a known at
2814 -- compile time length, then Len is set to this (non-negative
2815 -- length). Otherwise Len is set to minus 1.
2817 -----------------------
2818 -- Get_Static_Length --
2819 -----------------------
2821 procedure Get_Static_Length
(Op
: Node_Id
; Len
: out Uint
) is
2825 -- First easy case string literal
2827 if Nkind
(Op
) = N_String_Literal
then
2828 Len
:= UI_From_Int
(String_Length
(Strval
(Op
)));
2832 -- Second easy case, not constrained subtype, so no length
2834 if not Is_Constrained
(Etype
(Op
)) then
2835 Len
:= Uint_Minus_1
;
2841 T
:= Etype
(First_Index
(Etype
(Op
)));
2843 -- The simple case, both bounds are known at compile time
2845 if Is_Discrete_Type
(T
)
2847 Compile_Time_Known_Value
(Type_Low_Bound
(T
))
2849 Compile_Time_Known_Value
(Type_High_Bound
(T
))
2851 Len
:= UI_Max
(Uint_0
,
2852 Expr_Value
(Type_High_Bound
(T
)) -
2853 Expr_Value
(Type_Low_Bound
(T
)) + 1);
2857 -- A more complex case, where the bounds are of the form
2858 -- X [+/- K1] .. X [+/- K2]), where X is an expression that is
2859 -- either A'First or A'Last (with A an entity name), or X is an
2860 -- entity name, and the two X's are the same and K1 and K2 are
2861 -- known at compile time, in this case, the length can also be
2862 -- computed at compile time, even though the bounds are not
2863 -- known. A common case of this is e.g. (X'First .. X'First+5).
2865 Extract_Length
: declare
2866 procedure Decompose_Expr
2868 Ent
: out Entity_Id
;
2869 Kind
: out Character;
2871 -- Given an expression, see if is of the form above,
2872 -- X [+/- K]. If so Ent is set to the entity in X,
2873 -- Kind is 'F','L','E' for 'First/'Last/simple entity,
2874 -- and Cons is the value of K. If the expression is
2875 -- not of the required form, Ent is set to Empty.
2877 --------------------
2878 -- Decompose_Expr --
2879 --------------------
2881 procedure Decompose_Expr
2883 Ent
: out Entity_Id
;
2884 Kind
: out Character;
2890 if Nkind
(Expr
) = N_Op_Add
2891 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
2893 Exp
:= Left_Opnd
(Expr
);
2894 Cons
:= Expr_Value
(Right_Opnd
(Expr
));
2896 elsif Nkind
(Expr
) = N_Op_Subtract
2897 and then Compile_Time_Known_Value
(Right_Opnd
(Expr
))
2899 Exp
:= Left_Opnd
(Expr
);
2900 Cons
:= -Expr_Value
(Right_Opnd
(Expr
));
2902 -- If the bound is a constant created to remove side
2903 -- effects, recover original expression to see if it has
2904 -- one of the recognizable forms.
2906 elsif Nkind
(Expr
) = N_Identifier
2907 and then not Comes_From_Source
(Entity
(Expr
))
2908 and then Ekind
(Entity
(Expr
)) = E_Constant
2910 Nkind
(Parent
(Entity
(Expr
))) = N_Object_Declaration
2912 Exp
:= Expression
(Parent
(Entity
(Expr
)));
2913 Decompose_Expr
(Exp
, Ent
, Kind
, Cons
);
2915 -- If original expression includes an entity, create a
2916 -- reference to it for use below.
2918 if Present
(Ent
) then
2919 Exp
:= New_Occurrence_Of
(Ent
, Sloc
(Ent
));
2927 -- At this stage Exp is set to the potential X
2929 if Nkind
(Exp
) = N_Attribute_Reference
then
2930 if Attribute_Name
(Exp
) = Name_First
then
2933 elsif Attribute_Name
(Exp
) = Name_Last
then
2941 Exp
:= Prefix
(Exp
);
2947 if Is_Entity_Name
(Exp
)
2948 and then Present
(Entity
(Exp
))
2950 Ent
:= Entity
(Exp
);
2958 Ent1
, Ent2
: Entity_Id
;
2959 Kind1
, Kind2
: Character;
2960 Cons1
, Cons2
: Uint
;
2962 -- Start of processing for Extract_Length
2966 (Original_Node
(Type_Low_Bound
(T
)), Ent1
, Kind1
, Cons1
);
2968 (Original_Node
(Type_High_Bound
(T
)), Ent2
, Kind2
, Cons2
);
2971 and then Kind1
= Kind2
2972 and then Ent1
= Ent2
2974 Len
:= Cons2
- Cons1
+ 1;
2976 Len
:= Uint_Minus_1
;
2979 end Get_Static_Length
;
2986 -- Start of processing for Length_Mismatch
2989 Get_Static_Length
(Left
, Len_L
);
2990 Get_Static_Length
(Right
, Len_R
);
2992 if Len_L
/= Uint_Minus_1
2993 and then Len_R
/= Uint_Minus_1
2994 and then Len_L
/= Len_R
2996 Fold_Uint
(N
, Test
(Nkind
(N
) = N_Op_Ne
), False);
2997 Warn_On_Known_Condition
(N
);
3000 end Length_Mismatch
;
3004 Is_Static_Expression
: Boolean;
3005 Is_Foldable
: Boolean;
3006 pragma Unreferenced
(Is_Foldable
);
3009 -- Initialize the value of Is_Static_Expression. The value of
3010 -- Is_Foldable returned by Test_Expression_Is_Foldable is not needed
3011 -- since, even when some operand is a variable, we can still perform
3012 -- the static evaluation of the expression in some cases (for
3013 -- example, for a variable of a subtype of Integer we statically
3014 -- know that any value stored in such variable is smaller than
3017 Test_Expression_Is_Foldable
3018 (N
, Left
, Right
, Is_Static_Expression
, Is_Foldable
);
3020 -- Only comparisons of scalars can give static results. In
3021 -- particular, comparisons of strings never yield a static
3022 -- result, even if both operands are static strings.
3024 if not Is_Scalar_Type
(Typ
) then
3025 Is_Static_Expression
:= False;
3026 Set_Is_Static_Expression
(N
, False);
3029 -- For operators on universal numeric types called as functions with
3030 -- an explicit scope, determine appropriate specific numeric type,
3031 -- and diagnose possible ambiguity.
3033 if Is_Universal_Numeric_Type
(Etype
(Left
))
3035 Is_Universal_Numeric_Type
(Etype
(Right
))
3037 Otype
:= Find_Universal_Operator_Type
(N
);
3040 -- For static real type expressions, we cannot use
3041 -- Compile_Time_Compare since it worries about run-time
3042 -- results which are not exact.
3044 if Is_Static_Expression
and then Is_Real_Type
(Typ
) then
3046 Left_Real
: constant Ureal
:= Expr_Value_R
(Left
);
3047 Right_Real
: constant Ureal
:= Expr_Value_R
(Right
);
3051 when N_Op_Eq
=> Result
:= (Left_Real
= Right_Real
);
3052 when N_Op_Ne
=> Result
:= (Left_Real
/= Right_Real
);
3053 when N_Op_Lt
=> Result
:= (Left_Real
< Right_Real
);
3054 when N_Op_Le
=> Result
:= (Left_Real
<= Right_Real
);
3055 when N_Op_Gt
=> Result
:= (Left_Real
> Right_Real
);
3056 when N_Op_Ge
=> Result
:= (Left_Real
>= Right_Real
);
3059 raise Program_Error
;
3062 Fold_Uint
(N
, Test
(Result
), True);
3065 -- For all other cases, we use Compile_Time_Compare to do the compare
3069 CR
: constant Compare_Result
:=
3070 Compile_Time_Compare
3071 (Left
, Right
, Assume_Valid
=> False);
3074 if CR
= Unknown
then
3082 elsif CR
= NE
or else CR
= GT
or else CR
= LT
then
3089 if CR
= NE
or else CR
= GT
or else CR
= LT
then
3100 elsif CR
= EQ
or else CR
= GT
or else CR
= GE
then
3107 if CR
= LT
or else CR
= EQ
or else CR
= LE
then
3118 elsif CR
= EQ
or else CR
= LT
or else CR
= LE
then
3125 if CR
= GT
or else CR
= EQ
or else CR
= GE
then
3134 raise Program_Error
;
3138 Fold_Uint
(N
, Test
(Result
), Is_Static_Expression
);
3142 -- For the case of a folded relational operator on a specific numeric
3143 -- type, freeze operand type now.
3145 if Present
(Otype
) then
3146 Freeze_Before
(N
, Otype
);
3149 Warn_On_Known_Condition
(N
);
3150 end Eval_Relational_Op
;
3156 -- Shift operations are intrinsic operations that can never be static, so
3157 -- the only processing required is to perform the required check for a non
3158 -- static context for the two operands.
3160 -- Actually we could do some compile time evaluation here some time ???
3162 procedure Eval_Shift
(N
: Node_Id
) is
3164 Check_Non_Static_Context
(Left_Opnd
(N
));
3165 Check_Non_Static_Context
(Right_Opnd
(N
));
3168 ------------------------
3169 -- Eval_Short_Circuit --
3170 ------------------------
3172 -- A short circuit operation is potentially static if both operands are
3173 -- potentially static (RM 4.9 (13)).
3175 procedure Eval_Short_Circuit
(N
: Node_Id
) is
3176 Kind
: constant Node_Kind
:= Nkind
(N
);
3177 Left
: constant Node_Id
:= Left_Opnd
(N
);
3178 Right
: constant Node_Id
:= Right_Opnd
(N
);
3181 Rstat
: constant Boolean :=
3182 Is_Static_Expression
(Left
)
3184 Is_Static_Expression
(Right
);
3187 -- Short circuit operations are never static in Ada 83
3189 if Ada_Version
= Ada_83
and then Comes_From_Source
(N
) then
3190 Check_Non_Static_Context
(Left
);
3191 Check_Non_Static_Context
(Right
);
3195 -- Now look at the operands, we can't quite use the normal call to
3196 -- Test_Expression_Is_Foldable here because short circuit operations
3197 -- are a special case, they can still be foldable, even if the right
3198 -- operand raises constraint error.
3200 -- If either operand is Any_Type, just propagate to result and do not
3201 -- try to fold, this prevents cascaded errors.
3203 if Etype
(Left
) = Any_Type
or else Etype
(Right
) = Any_Type
then
3204 Set_Etype
(N
, Any_Type
);
3207 -- If left operand raises constraint error, then replace node N with
3208 -- the raise constraint error node, and we are obviously not foldable.
3209 -- Is_Static_Expression is set from the two operands in the normal way,
3210 -- and we check the right operand if it is in a non-static context.
3212 elsif Raises_Constraint_Error
(Left
) then
3214 Check_Non_Static_Context
(Right
);
3217 Rewrite_In_Raise_CE
(N
, Left
);
3218 Set_Is_Static_Expression
(N
, Rstat
);
3221 -- If the result is not static, then we won't in any case fold
3223 elsif not Rstat
then
3224 Check_Non_Static_Context
(Left
);
3225 Check_Non_Static_Context
(Right
);
3229 -- Here the result is static, note that, unlike the normal processing
3230 -- in Test_Expression_Is_Foldable, we did *not* check above to see if
3231 -- the right operand raises constraint error, that's because it is not
3232 -- significant if the left operand is decisive.
3234 Set_Is_Static_Expression
(N
);
3236 -- It does not matter if the right operand raises constraint error if
3237 -- it will not be evaluated. So deal specially with the cases where
3238 -- the right operand is not evaluated. Note that we will fold these
3239 -- cases even if the right operand is non-static, which is fine, but
3240 -- of course in these cases the result is not potentially static.
3242 Left_Int
:= Expr_Value
(Left
);
3244 if (Kind
= N_And_Then
and then Is_False
(Left_Int
))
3246 (Kind
= N_Or_Else
and then Is_True
(Left_Int
))
3248 Fold_Uint
(N
, Left_Int
, Rstat
);
3252 -- If first operand not decisive, then it does matter if the right
3253 -- operand raises constraint error, since it will be evaluated, so
3254 -- we simply replace the node with the right operand. Note that this
3255 -- properly propagates Is_Static_Expression and Raises_Constraint_Error
3256 -- (both are set to True in Right).
3258 if Raises_Constraint_Error
(Right
) then
3259 Rewrite_In_Raise_CE
(N
, Right
);
3260 Check_Non_Static_Context
(Left
);
3264 -- Otherwise the result depends on the right operand
3266 Fold_Uint
(N
, Expr_Value
(Right
), Rstat
);
3268 end Eval_Short_Circuit
;
3274 -- Slices can never be static, so the only processing required is to check
3275 -- for non-static context if an explicit range is given.
3277 procedure Eval_Slice
(N
: Node_Id
) is
3278 Drange
: constant Node_Id
:= Discrete_Range
(N
);
3280 if Nkind
(Drange
) = N_Range
then
3281 Check_Non_Static_Context
(Low_Bound
(Drange
));
3282 Check_Non_Static_Context
(High_Bound
(Drange
));
3285 -- A slice of the form A (subtype), when the subtype is the index of
3286 -- the type of A, is redundant, the slice can be replaced with A, and
3287 -- this is worth a warning.
3289 if Is_Entity_Name
(Prefix
(N
)) then
3291 E
: constant Entity_Id
:= Entity
(Prefix
(N
));
3292 T
: constant Entity_Id
:= Etype
(E
);
3294 if Ekind
(E
) = E_Constant
3295 and then Is_Array_Type
(T
)
3296 and then Is_Entity_Name
(Drange
)
3298 if Is_Entity_Name
(Original_Node
(First_Index
(T
)))
3299 and then Entity
(Original_Node
(First_Index
(T
)))
3302 if Warn_On_Redundant_Constructs
then
3303 Error_Msg_N
("redundant slice denotes whole array?r?", N
);
3306 -- The following might be a useful optimization???
3308 -- Rewrite (N, New_Occurrence_Of (E, Sloc (N)));
3315 ---------------------------------
3316 -- Eval_Static_Predicate_Check --
3317 ---------------------------------
3319 function Eval_Static_Predicate_Check
3321 Typ
: Entity_Id
) return Boolean
3323 Loc
: constant Source_Ptr
:= Sloc
(N
);
3324 Pred
: constant List_Id
:= Static_Predicate
(Typ
);
3332 -- The static predicate is a list of alternatives in the proper format
3333 -- for an Ada 2012 membership test. If the argument is a literal, the
3334 -- membership test can be evaluated statically. The caller transforms
3335 -- a result of False into a static contraint error.
3337 Test
:= Make_In
(Loc
,
3338 Left_Opnd
=> New_Copy_Tree
(N
),
3339 Right_Opnd
=> Empty
,
3340 Alternatives
=> Pred
);
3341 Analyze_And_Resolve
(Test
, Standard_Boolean
);
3343 return Nkind
(Test
) = N_Identifier
3344 and then Entity
(Test
) = Standard_True
;
3345 end Eval_Static_Predicate_Check
;
3347 -------------------------
3348 -- Eval_String_Literal --
3349 -------------------------
3351 procedure Eval_String_Literal
(N
: Node_Id
) is
3352 Typ
: constant Entity_Id
:= Etype
(N
);
3353 Bas
: constant Entity_Id
:= Base_Type
(Typ
);
3359 -- Nothing to do if error type (handles cases like default expressions
3360 -- or generics where we have not yet fully resolved the type).
3362 if Bas
= Any_Type
or else Bas
= Any_String
then
3366 -- String literals are static if the subtype is static (RM 4.9(2)), so
3367 -- reset the static expression flag (it was set unconditionally in
3368 -- Analyze_String_Literal) if the subtype is non-static. We tell if
3369 -- the subtype is static by looking at the lower bound.
3371 if Ekind
(Typ
) = E_String_Literal_Subtype
then
3372 if not Is_OK_Static_Expression
(String_Literal_Low_Bound
(Typ
)) then
3373 Set_Is_Static_Expression
(N
, False);
3377 -- Here if Etype of string literal is normal Etype (not yet possible,
3378 -- but may be possible in future).
3380 elsif not Is_OK_Static_Expression
3381 (Type_Low_Bound
(Etype
(First_Index
(Typ
))))
3383 Set_Is_Static_Expression
(N
, False);
3387 -- If original node was a type conversion, then result if non-static
3389 if Nkind
(Original_Node
(N
)) = N_Type_Conversion
then
3390 Set_Is_Static_Expression
(N
, False);
3394 -- Test for illegal Ada 95 cases. A string literal is illegal in Ada 95
3395 -- if its bounds are outside the index base type and this index type is
3396 -- static. This can happen in only two ways. Either the string literal
3397 -- is too long, or it is null, and the lower bound is type'First. In
3398 -- either case it is the upper bound that is out of range of the index
3400 if Ada_Version
>= Ada_95
then
3401 if Root_Type
(Bas
) = Standard_String
3403 Root_Type
(Bas
) = Standard_Wide_String
3405 Root_Type
(Bas
) = Standard_Wide_Wide_String
3407 Xtp
:= Standard_Positive
;
3409 Xtp
:= Etype
(First_Index
(Bas
));
3412 if Ekind
(Typ
) = E_String_Literal_Subtype
then
3413 Lo
:= String_Literal_Low_Bound
(Typ
);
3415 Lo
:= Type_Low_Bound
(Etype
(First_Index
(Typ
)));
3418 -- Check for string too long
3420 Len
:= String_Length
(Strval
(N
));
3422 if UI_From_Int
(Len
) > String_Type_Len
(Bas
) then
3424 -- Issue message. Note that this message is a warning if the
3425 -- string literal is not marked as static (happens in some cases
3426 -- of folding strings known at compile time, but not static).
3427 -- Furthermore in such cases, we reword the message, since there
3428 -- is no string literal in the source program.
3430 if Is_Static_Expression
(N
) then
3431 Apply_Compile_Time_Constraint_Error
3432 (N
, "string literal too long for}", CE_Length_Check_Failed
,
3434 Typ
=> First_Subtype
(Bas
));
3436 Apply_Compile_Time_Constraint_Error
3437 (N
, "string value too long for}", CE_Length_Check_Failed
,
3439 Typ
=> First_Subtype
(Bas
),
3443 -- Test for null string not allowed
3446 and then not Is_Generic_Type
(Xtp
)
3448 Expr_Value
(Lo
) = Expr_Value
(Type_Low_Bound
(Base_Type
(Xtp
)))
3450 -- Same specialization of message
3452 if Is_Static_Expression
(N
) then
3453 Apply_Compile_Time_Constraint_Error
3454 (N
, "null string literal not allowed for}",
3455 CE_Length_Check_Failed
,
3457 Typ
=> First_Subtype
(Bas
));
3459 Apply_Compile_Time_Constraint_Error
3460 (N
, "null string value not allowed for}",
3461 CE_Length_Check_Failed
,
3463 Typ
=> First_Subtype
(Bas
),
3468 end Eval_String_Literal
;
3470 --------------------------
3471 -- Eval_Type_Conversion --
3472 --------------------------
3474 -- A type conversion is potentially static if its subtype mark is for a
3475 -- static scalar subtype, and its operand expression is potentially static
3478 procedure Eval_Type_Conversion
(N
: Node_Id
) is
3479 Operand
: constant Node_Id
:= Expression
(N
);
3480 Source_Type
: constant Entity_Id
:= Etype
(Operand
);
3481 Target_Type
: constant Entity_Id
:= Etype
(N
);
3486 function To_Be_Treated_As_Integer
(T
: Entity_Id
) return Boolean;
3487 -- Returns true if type T is an integer type, or if it is a fixed-point
3488 -- type to be treated as an integer (i.e. the flag Conversion_OK is set
3489 -- on the conversion node).
3491 function To_Be_Treated_As_Real
(T
: Entity_Id
) return Boolean;
3492 -- Returns true if type T is a floating-point type, or if it is a
3493 -- fixed-point type that is not to be treated as an integer (i.e. the
3494 -- flag Conversion_OK is not set on the conversion node).
3496 ------------------------------
3497 -- To_Be_Treated_As_Integer --
3498 ------------------------------
3500 function To_Be_Treated_As_Integer
(T
: Entity_Id
) return Boolean is
3504 or else (Is_Fixed_Point_Type
(T
) and then Conversion_OK
(N
));
3505 end To_Be_Treated_As_Integer
;
3507 ---------------------------
3508 -- To_Be_Treated_As_Real --
3509 ---------------------------
3511 function To_Be_Treated_As_Real
(T
: Entity_Id
) return Boolean is
3514 Is_Floating_Point_Type
(T
)
3515 or else (Is_Fixed_Point_Type
(T
) and then not Conversion_OK
(N
));
3516 end To_Be_Treated_As_Real
;
3518 -- Start of processing for Eval_Type_Conversion
3521 -- Cannot fold if target type is non-static or if semantic error
3523 if not Is_Static_Subtype
(Target_Type
) then
3524 Check_Non_Static_Context
(Operand
);
3527 elsif Error_Posted
(N
) then
3531 -- If not foldable we are done
3533 Test_Expression_Is_Foldable
(N
, Operand
, Stat
, Fold
);
3538 -- Don't try fold if target type has constraint error bounds
3540 elsif not Is_OK_Static_Subtype
(Target_Type
) then
3541 Set_Raises_Constraint_Error
(N
);
3545 -- Remaining processing depends on operand types. Note that in the
3546 -- following type test, fixed-point counts as real unless the flag
3547 -- Conversion_OK is set, in which case it counts as integer.
3549 -- Fold conversion, case of string type. The result is not static
3551 if Is_String_Type
(Target_Type
) then
3552 Fold_Str
(N
, Strval
(Get_String_Val
(Operand
)), Static
=> False);
3556 -- Fold conversion, case of integer target type
3558 elsif To_Be_Treated_As_Integer
(Target_Type
) then
3563 -- Integer to integer conversion
3565 if To_Be_Treated_As_Integer
(Source_Type
) then
3566 Result
:= Expr_Value
(Operand
);
3568 -- Real to integer conversion
3571 Result
:= UR_To_Uint
(Expr_Value_R
(Operand
));
3574 -- If fixed-point type (Conversion_OK must be set), then the
3575 -- result is logically an integer, but we must replace the
3576 -- conversion with the corresponding real literal, since the
3577 -- type from a semantic point of view is still fixed-point.
3579 if Is_Fixed_Point_Type
(Target_Type
) then
3581 (N
, UR_From_Uint
(Result
) * Small_Value
(Target_Type
), Stat
);
3583 -- Otherwise result is integer literal
3586 Fold_Uint
(N
, Result
, Stat
);
3590 -- Fold conversion, case of real target type
3592 elsif To_Be_Treated_As_Real
(Target_Type
) then
3597 if To_Be_Treated_As_Real
(Source_Type
) then
3598 Result
:= Expr_Value_R
(Operand
);
3600 Result
:= UR_From_Uint
(Expr_Value
(Operand
));
3603 Fold_Ureal
(N
, Result
, Stat
);
3606 -- Enumeration types
3609 Fold_Uint
(N
, Expr_Value
(Operand
), Stat
);
3612 if Is_Out_Of_Range
(N
, Etype
(N
), Assume_Valid
=> True) then
3616 end Eval_Type_Conversion
;
3622 -- Predefined unary operators are static functions (RM 4.9(20)) and thus
3623 -- are potentially static if the operand is potentially static (RM 4.9(7)).
3625 procedure Eval_Unary_Op
(N
: Node_Id
) is
3626 Right
: constant Node_Id
:= Right_Opnd
(N
);
3627 Otype
: Entity_Id
:= Empty
;
3632 -- If not foldable we are done
3634 Test_Expression_Is_Foldable
(N
, Right
, Stat
, Fold
);
3640 if Etype
(Right
) = Universal_Integer
3642 Etype
(Right
) = Universal_Real
3644 Otype
:= Find_Universal_Operator_Type
(N
);
3647 -- Fold for integer case
3649 if Is_Integer_Type
(Etype
(N
)) then
3651 Rint
: constant Uint
:= Expr_Value
(Right
);
3655 -- In the case of modular unary plus and abs there is no need
3656 -- to adjust the result of the operation since if the original
3657 -- operand was in bounds the result will be in the bounds of the
3658 -- modular type. However, in the case of modular unary minus the
3659 -- result may go out of the bounds of the modular type and needs
3662 if Nkind
(N
) = N_Op_Plus
then
3665 elsif Nkind
(N
) = N_Op_Minus
then
3666 if Is_Modular_Integer_Type
(Etype
(N
)) then
3667 Result
:= (-Rint
) mod Modulus
(Etype
(N
));
3673 pragma Assert
(Nkind
(N
) = N_Op_Abs
);
3677 Fold_Uint
(N
, Result
, Stat
);
3680 -- Fold for real case
3682 elsif Is_Real_Type
(Etype
(N
)) then
3684 Rreal
: constant Ureal
:= Expr_Value_R
(Right
);
3688 if Nkind
(N
) = N_Op_Plus
then
3691 elsif Nkind
(N
) = N_Op_Minus
then
3692 Result
:= UR_Negate
(Rreal
);
3695 pragma Assert
(Nkind
(N
) = N_Op_Abs
);
3696 Result
:= abs Rreal
;
3699 Fold_Ureal
(N
, Result
, Stat
);
3703 -- If the operator was resolved to a specific type, make sure that type
3704 -- is frozen even if the expression is folded into a literal (which has
3705 -- a universal type).
3707 if Present
(Otype
) then
3708 Freeze_Before
(N
, Otype
);
3712 -------------------------------
3713 -- Eval_Unchecked_Conversion --
3714 -------------------------------
3716 -- Unchecked conversions can never be static, so the only required
3717 -- processing is to check for a non-static context for the operand.
3719 procedure Eval_Unchecked_Conversion
(N
: Node_Id
) is
3721 Check_Non_Static_Context
(Expression
(N
));
3722 end Eval_Unchecked_Conversion
;
3724 --------------------
3725 -- Expr_Rep_Value --
3726 --------------------
3728 function Expr_Rep_Value
(N
: Node_Id
) return Uint
is
3729 Kind
: constant Node_Kind
:= Nkind
(N
);
3733 if Is_Entity_Name
(N
) then
3736 -- An enumeration literal that was either in the source or created
3737 -- as a result of static evaluation.
3739 if Ekind
(Ent
) = E_Enumeration_Literal
then
3740 return Enumeration_Rep
(Ent
);
3742 -- A user defined static constant
3745 pragma Assert
(Ekind
(Ent
) = E_Constant
);
3746 return Expr_Rep_Value
(Constant_Value
(Ent
));
3749 -- An integer literal that was either in the source or created as a
3750 -- result of static evaluation.
3752 elsif Kind
= N_Integer_Literal
then
3755 -- A real literal for a fixed-point type. This must be the fixed-point
3756 -- case, either the literal is of a fixed-point type, or it is a bound
3757 -- of a fixed-point type, with type universal real. In either case we
3758 -- obtain the desired value from Corresponding_Integer_Value.
3760 elsif Kind
= N_Real_Literal
then
3761 pragma Assert
(Is_Fixed_Point_Type
(Underlying_Type
(Etype
(N
))));
3762 return Corresponding_Integer_Value
(N
);
3764 -- Peculiar VMS case, if we have xxx'Null_Parameter, return zero
3766 elsif Kind
= N_Attribute_Reference
3767 and then Attribute_Name
(N
) = Name_Null_Parameter
3771 -- Otherwise must be character literal
3774 pragma Assert
(Kind
= N_Character_Literal
);
3777 -- Since Character literals of type Standard.Character don't have any
3778 -- defining character literals built for them, they do not have their
3779 -- Entity set, so just use their Char code. Otherwise for user-
3780 -- defined character literals use their Pos value as usual which is
3781 -- the same as the Rep value.
3784 return Char_Literal_Value
(N
);
3786 return Enumeration_Rep
(Ent
);
3795 function Expr_Value
(N
: Node_Id
) return Uint
is
3796 Kind
: constant Node_Kind
:= Nkind
(N
);
3797 CV_Ent
: CV_Entry
renames CV_Cache
(Nat
(N
) mod CV_Cache_Size
);
3802 -- If already in cache, then we know it's compile time known and we can
3803 -- return the value that was previously stored in the cache since
3804 -- compile time known values cannot change.
3806 if CV_Ent
.N
= N
then
3810 -- Otherwise proceed to test value
3812 if Is_Entity_Name
(N
) then
3815 -- An enumeration literal that was either in the source or created as
3816 -- a result of static evaluation.
3818 if Ekind
(Ent
) = E_Enumeration_Literal
then
3819 Val
:= Enumeration_Pos
(Ent
);
3821 -- A user defined static constant
3824 pragma Assert
(Ekind
(Ent
) = E_Constant
);
3825 Val
:= Expr_Value
(Constant_Value
(Ent
));
3828 -- An integer literal that was either in the source or created as a
3829 -- result of static evaluation.
3831 elsif Kind
= N_Integer_Literal
then
3834 -- A real literal for a fixed-point type. This must be the fixed-point
3835 -- case, either the literal is of a fixed-point type, or it is a bound
3836 -- of a fixed-point type, with type universal real. In either case we
3837 -- obtain the desired value from Corresponding_Integer_Value.
3839 elsif Kind
= N_Real_Literal
then
3841 pragma Assert
(Is_Fixed_Point_Type
(Underlying_Type
(Etype
(N
))));
3842 Val
:= Corresponding_Integer_Value
(N
);
3844 -- Peculiar VMS case, if we have xxx'Null_Parameter, return zero
3846 elsif Kind
= N_Attribute_Reference
3847 and then Attribute_Name
(N
) = Name_Null_Parameter
3851 -- Otherwise must be character literal
3854 pragma Assert
(Kind
= N_Character_Literal
);
3857 -- Since Character literals of type Standard.Character don't
3858 -- have any defining character literals built for them, they
3859 -- do not have their Entity set, so just use their Char
3860 -- code. Otherwise for user-defined character literals use
3861 -- their Pos value as usual.
3864 Val
:= Char_Literal_Value
(N
);
3866 Val
:= Enumeration_Pos
(Ent
);
3870 -- Come here with Val set to value to be returned, set cache
3881 function Expr_Value_E
(N
: Node_Id
) return Entity_Id
is
3882 Ent
: constant Entity_Id
:= Entity
(N
);
3885 if Ekind
(Ent
) = E_Enumeration_Literal
then
3888 pragma Assert
(Ekind
(Ent
) = E_Constant
);
3889 return Expr_Value_E
(Constant_Value
(Ent
));
3897 function Expr_Value_R
(N
: Node_Id
) return Ureal
is
3898 Kind
: constant Node_Kind
:= Nkind
(N
);
3902 if Kind
= N_Real_Literal
then
3905 elsif Kind
= N_Identifier
or else Kind
= N_Expanded_Name
then
3907 pragma Assert
(Ekind
(Ent
) = E_Constant
);
3908 return Expr_Value_R
(Constant_Value
(Ent
));
3910 elsif Kind
= N_Integer_Literal
then
3911 return UR_From_Uint
(Expr_Value
(N
));
3913 -- Peculiar VMS case, if we have xxx'Null_Parameter, return 0.0
3915 elsif Kind
= N_Attribute_Reference
3916 and then Attribute_Name
(N
) = Name_Null_Parameter
3921 -- If we fall through, we have a node that cannot be interpreted as a
3922 -- compile time constant. That is definitely an error.
3924 raise Program_Error
;
3931 function Expr_Value_S
(N
: Node_Id
) return Node_Id
is
3933 if Nkind
(N
) = N_String_Literal
then
3936 pragma Assert
(Ekind
(Entity
(N
)) = E_Constant
);
3937 return Expr_Value_S
(Constant_Value
(Entity
(N
)));
3941 ----------------------------------
3942 -- Find_Universal_Operator_Type --
3943 ----------------------------------
3945 function Find_Universal_Operator_Type
(N
: Node_Id
) return Entity_Id
is
3946 PN
: constant Node_Id
:= Parent
(N
);
3947 Call
: constant Node_Id
:= Original_Node
(N
);
3948 Is_Int
: constant Boolean := Is_Integer_Type
(Etype
(N
));
3950 Is_Fix
: constant Boolean :=
3951 Nkind
(N
) in N_Binary_Op
3952 and then Nkind
(Right_Opnd
(N
)) /= Nkind
(Left_Opnd
(N
));
3953 -- A mixed-mode operation in this context indicates the presence of
3954 -- fixed-point type in the designated package.
3956 Is_Relational
: constant Boolean := Etype
(N
) = Standard_Boolean
;
3957 -- Case where N is a relational (or membership) operator (else it is an
3960 In_Membership
: constant Boolean :=
3961 Nkind
(PN
) in N_Membership_Test
3963 Nkind
(Right_Opnd
(PN
)) = N_Range
3965 Is_Universal_Numeric_Type
(Etype
(Left_Opnd
(PN
)))
3967 Is_Universal_Numeric_Type
3968 (Etype
(Low_Bound
(Right_Opnd
(PN
))))
3970 Is_Universal_Numeric_Type
3971 (Etype
(High_Bound
(Right_Opnd
(PN
))));
3972 -- Case where N is part of a membership test with a universal range
3976 Typ1
: Entity_Id
:= Empty
;
3979 function Is_Mixed_Mode_Operand
(Op
: Node_Id
) return Boolean;
3980 -- Check whether one operand is a mixed-mode operation that requires the
3981 -- presence of a fixed-point type. Given that all operands are universal
3982 -- and have been constant-folded, retrieve the original function call.
3984 ---------------------------
3985 -- Is_Mixed_Mode_Operand --
3986 ---------------------------
3988 function Is_Mixed_Mode_Operand
(Op
: Node_Id
) return Boolean is
3989 Onod
: constant Node_Id
:= Original_Node
(Op
);
3991 return Nkind
(Onod
) = N_Function_Call
3992 and then Present
(Next_Actual
(First_Actual
(Onod
)))
3993 and then Etype
(First_Actual
(Onod
)) /=
3994 Etype
(Next_Actual
(First_Actual
(Onod
)));
3995 end Is_Mixed_Mode_Operand
;
3997 -- Start of processing for Find_Universal_Operator_Type
4000 if Nkind
(Call
) /= N_Function_Call
4001 or else Nkind
(Name
(Call
)) /= N_Expanded_Name
4005 -- There are several cases where the context does not imply the type of
4007 -- - the universal expression appears in a type conversion;
4008 -- - the expression is a relational operator applied to universal
4010 -- - the expression is a membership test with a universal operand
4011 -- and a range with universal bounds.
4013 elsif Nkind
(Parent
(N
)) = N_Type_Conversion
4014 or else Is_Relational
4015 or else In_Membership
4017 Pack
:= Entity
(Prefix
(Name
(Call
)));
4019 -- If the prefix is a package declared elsewhere, iterate over its
4020 -- visible entities, otherwise iterate over all declarations in the
4021 -- designated scope.
4023 if Ekind
(Pack
) = E_Package
4024 and then not In_Open_Scopes
(Pack
)
4026 Priv_E
:= First_Private_Entity
(Pack
);
4032 E
:= First_Entity
(Pack
);
4033 while Present
(E
) and then E
/= Priv_E
loop
4034 if Is_Numeric_Type
(E
)
4035 and then Nkind
(Parent
(E
)) /= N_Subtype_Declaration
4036 and then Comes_From_Source
(E
)
4037 and then Is_Integer_Type
(E
) = Is_Int
4039 (Nkind
(N
) in N_Unary_Op
4040 or else Is_Relational
4041 or else Is_Fixed_Point_Type
(E
) = Is_Fix
)
4046 -- Before emitting an error, check for the presence of a
4047 -- mixed-mode operation that specifies a fixed point type.
4051 (Is_Mixed_Mode_Operand
(Left_Opnd
(N
))
4052 or else Is_Mixed_Mode_Operand
(Right_Opnd
(N
)))
4053 and then Is_Fixed_Point_Type
(E
) /= Is_Fixed_Point_Type
(Typ1
)
4056 if Is_Fixed_Point_Type
(E
) then
4061 -- More than one type of the proper class declared in P
4063 Error_Msg_N
("ambiguous operation", N
);
4064 Error_Msg_Sloc
:= Sloc
(Typ1
);
4065 Error_Msg_N
("\possible interpretation (inherited)#", N
);
4066 Error_Msg_Sloc
:= Sloc
(E
);
4067 Error_Msg_N
("\possible interpretation (inherited)#", N
);
4077 end Find_Universal_Operator_Type
;
4079 --------------------------
4080 -- Flag_Non_Static_Expr --
4081 --------------------------
4083 procedure Flag_Non_Static_Expr
(Msg
: String; Expr
: Node_Id
) is
4085 if Error_Posted
(Expr
) and then not All_Errors_Mode
then
4088 Error_Msg_F
(Msg
, Expr
);
4089 Why_Not_Static
(Expr
);
4091 end Flag_Non_Static_Expr
;
4097 procedure Fold_Str
(N
: Node_Id
; Val
: String_Id
; Static
: Boolean) is
4098 Loc
: constant Source_Ptr
:= Sloc
(N
);
4099 Typ
: constant Entity_Id
:= Etype
(N
);
4102 Rewrite
(N
, Make_String_Literal
(Loc
, Strval
=> Val
));
4104 -- We now have the literal with the right value, both the actual type
4105 -- and the expected type of this literal are taken from the expression
4106 -- that was evaluated. So now we do the Analyze and Resolve.
4108 -- Note that we have to reset Is_Static_Expression both after the
4109 -- analyze step (because Resolve will evaluate the literal, which
4110 -- will cause semantic errors if it is marked as static), and after
4111 -- the Resolve step (since Resolve in some cases resets this flag).
4114 Set_Is_Static_Expression
(N
, Static
);
4117 Set_Is_Static_Expression
(N
, Static
);
4124 procedure Fold_Uint
(N
: Node_Id
; Val
: Uint
; Static
: Boolean) is
4125 Loc
: constant Source_Ptr
:= Sloc
(N
);
4126 Typ
: Entity_Id
:= Etype
(N
);
4130 -- If we are folding a named number, retain the entity in the literal,
4133 if Is_Entity_Name
(N
)
4134 and then Ekind
(Entity
(N
)) = E_Named_Integer
4141 if Is_Private_Type
(Typ
) then
4142 Typ
:= Full_View
(Typ
);
4145 -- For a result of type integer, substitute an N_Integer_Literal node
4146 -- for the result of the compile time evaluation of the expression.
4147 -- For ASIS use, set a link to the original named number when not in
4148 -- a generic context.
4150 if Is_Integer_Type
(Typ
) then
4151 Rewrite
(N
, Make_Integer_Literal
(Loc
, Val
));
4153 Set_Original_Entity
(N
, Ent
);
4155 -- Otherwise we have an enumeration type, and we substitute either
4156 -- an N_Identifier or N_Character_Literal to represent the enumeration
4157 -- literal corresponding to the given value, which must always be in
4158 -- range, because appropriate tests have already been made for this.
4160 else pragma Assert
(Is_Enumeration_Type
(Typ
));
4161 Rewrite
(N
, Get_Enum_Lit_From_Pos
(Etype
(N
), Val
, Loc
));
4164 -- We now have the literal with the right value, both the actual type
4165 -- and the expected type of this literal are taken from the expression
4166 -- that was evaluated. So now we do the Analyze and Resolve.
4168 -- Note that we have to reset Is_Static_Expression both after the
4169 -- analyze step (because Resolve will evaluate the literal, which
4170 -- will cause semantic errors if it is marked as static), and after
4171 -- the Resolve step (since Resolve in some cases sets this flag).
4174 Set_Is_Static_Expression
(N
, Static
);
4177 Set_Is_Static_Expression
(N
, Static
);
4184 procedure Fold_Ureal
(N
: Node_Id
; Val
: Ureal
; Static
: Boolean) is
4185 Loc
: constant Source_Ptr
:= Sloc
(N
);
4186 Typ
: constant Entity_Id
:= Etype
(N
);
4190 -- If we are folding a named number, retain the entity in the literal,
4193 if Is_Entity_Name
(N
)
4194 and then Ekind
(Entity
(N
)) = E_Named_Real
4201 Rewrite
(N
, Make_Real_Literal
(Loc
, Realval
=> Val
));
4203 -- Set link to original named number, for ASIS use
4205 Set_Original_Entity
(N
, Ent
);
4207 -- We now have the literal with the right value, both the actual type
4208 -- and the expected type of this literal are taken from the expression
4209 -- that was evaluated. So now we do the Analyze and Resolve.
4211 -- Note that we have to reset Is_Static_Expression both after the
4212 -- analyze step (because Resolve will evaluate the literal, which
4213 -- will cause semantic errors if it is marked as static), and after
4214 -- the Resolve step (since Resolve in some cases sets this flag).
4217 Set_Is_Static_Expression
(N
, Static
);
4220 Set_Is_Static_Expression
(N
, Static
);
4227 function From_Bits
(B
: Bits
; T
: Entity_Id
) return Uint
is
4231 for J
in 0 .. B
'Last loop
4237 if Non_Binary_Modulus
(T
) then
4238 V
:= V
mod Modulus
(T
);
4244 --------------------
4245 -- Get_String_Val --
4246 --------------------
4248 function Get_String_Val
(N
: Node_Id
) return Node_Id
is
4250 if Nkind
(N
) = N_String_Literal
then
4253 elsif Nkind
(N
) = N_Character_Literal
then
4257 pragma Assert
(Is_Entity_Name
(N
));
4258 return Get_String_Val
(Constant_Value
(Entity
(N
)));
4266 procedure Initialize
is
4268 CV_Cache
:= (others => (Node_High_Bound
, Uint_0
));
4271 --------------------
4272 -- In_Subrange_Of --
4273 --------------------
4275 function In_Subrange_Of
4278 Fixed_Int
: Boolean := False) return Boolean
4287 if T1
= T2
or else Is_Subtype_Of
(T1
, T2
) then
4290 -- Never in range if both types are not scalar. Don't know if this can
4291 -- actually happen, but just in case.
4293 elsif not Is_Scalar_Type
(T1
) or else not Is_Scalar_Type
(T2
) then
4296 -- If T1 has infinities but T2 doesn't have infinities, then T1 is
4297 -- definitely not compatible with T2.
4299 elsif Is_Floating_Point_Type
(T1
)
4300 and then Has_Infinities
(T1
)
4301 and then Is_Floating_Point_Type
(T2
)
4302 and then not Has_Infinities
(T2
)
4307 L1
:= Type_Low_Bound
(T1
);
4308 H1
:= Type_High_Bound
(T1
);
4310 L2
:= Type_Low_Bound
(T2
);
4311 H2
:= Type_High_Bound
(T2
);
4313 -- Check bounds to see if comparison possible at compile time
4315 if Compile_Time_Compare
(L1
, L2
, Assume_Valid
=> True) in Compare_GE
4317 Compile_Time_Compare
(H1
, H2
, Assume_Valid
=> True) in Compare_LE
4322 -- If bounds not comparable at compile time, then the bounds of T2
4323 -- must be compile time known or we cannot answer the query.
4325 if not Compile_Time_Known_Value
(L2
)
4326 or else not Compile_Time_Known_Value
(H2
)
4331 -- If the bounds of T1 are know at compile time then use these
4332 -- ones, otherwise use the bounds of the base type (which are of
4333 -- course always static).
4335 if not Compile_Time_Known_Value
(L1
) then
4336 L1
:= Type_Low_Bound
(Base_Type
(T1
));
4339 if not Compile_Time_Known_Value
(H1
) then
4340 H1
:= Type_High_Bound
(Base_Type
(T1
));
4343 -- Fixed point types should be considered as such only if
4344 -- flag Fixed_Int is set to False.
4346 if Is_Floating_Point_Type
(T1
) or else Is_Floating_Point_Type
(T2
)
4347 or else (Is_Fixed_Point_Type
(T1
) and then not Fixed_Int
)
4348 or else (Is_Fixed_Point_Type
(T2
) and then not Fixed_Int
)
4351 Expr_Value_R
(L2
) <= Expr_Value_R
(L1
)
4353 Expr_Value_R
(H2
) >= Expr_Value_R
(H1
);
4357 Expr_Value
(L2
) <= Expr_Value
(L1
)
4359 Expr_Value
(H2
) >= Expr_Value
(H1
);
4364 -- If any exception occurs, it means that we have some bug in the compiler
4365 -- possibly triggered by a previous error, or by some unforeseen peculiar
4366 -- occurrence. However, this is only an optimization attempt, so there is
4367 -- really no point in crashing the compiler. Instead we just decide, too
4368 -- bad, we can't figure out the answer in this case after all.
4373 -- Debug flag K disables this behavior (useful for debugging)
4375 if Debug_Flag_K
then
4386 function Is_In_Range
4389 Assume_Valid
: Boolean := False;
4390 Fixed_Int
: Boolean := False;
4391 Int_Real
: Boolean := False) return Boolean
4394 return Test_In_Range
(N
, Typ
, Assume_Valid
, Fixed_Int
, Int_Real
)
4402 function Is_Null_Range
(Lo
: Node_Id
; Hi
: Node_Id
) return Boolean is
4403 Typ
: constant Entity_Id
:= Etype
(Lo
);
4406 if not Compile_Time_Known_Value
(Lo
)
4407 or else not Compile_Time_Known_Value
(Hi
)
4412 if Is_Discrete_Type
(Typ
) then
4413 return Expr_Value
(Lo
) > Expr_Value
(Hi
);
4416 pragma Assert
(Is_Real_Type
(Typ
));
4417 return Expr_Value_R
(Lo
) > Expr_Value_R
(Hi
);
4421 -----------------------------
4422 -- Is_OK_Static_Expression --
4423 -----------------------------
4425 function Is_OK_Static_Expression
(N
: Node_Id
) return Boolean is
4427 return Is_Static_Expression
(N
)
4428 and then not Raises_Constraint_Error
(N
);
4429 end Is_OK_Static_Expression
;
4431 ------------------------
4432 -- Is_OK_Static_Range --
4433 ------------------------
4435 -- A static range is a range whose bounds are static expressions, or a
4436 -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)).
4437 -- We have already converted range attribute references, so we get the
4438 -- "or" part of this rule without needing a special test.
4440 function Is_OK_Static_Range
(N
: Node_Id
) return Boolean is
4442 return Is_OK_Static_Expression
(Low_Bound
(N
))
4443 and then Is_OK_Static_Expression
(High_Bound
(N
));
4444 end Is_OK_Static_Range
;
4446 --------------------------
4447 -- Is_OK_Static_Subtype --
4448 --------------------------
4450 -- Determines if Typ is a static subtype as defined in (RM 4.9(26)) where
4451 -- neither bound raises constraint error when evaluated.
4453 function Is_OK_Static_Subtype
(Typ
: Entity_Id
) return Boolean is
4454 Base_T
: constant Entity_Id
:= Base_Type
(Typ
);
4455 Anc_Subt
: Entity_Id
;
4458 -- First a quick check on the non static subtype flag. As described
4459 -- in further detail in Einfo, this flag is not decisive in all cases,
4460 -- but if it is set, then the subtype is definitely non-static.
4462 if Is_Non_Static_Subtype
(Typ
) then
4466 Anc_Subt
:= Ancestor_Subtype
(Typ
);
4468 if Anc_Subt
= Empty
then
4472 if Is_Generic_Type
(Root_Type
(Base_T
))
4473 or else Is_Generic_Actual_Type
(Base_T
)
4479 elsif Is_String_Type
(Typ
) then
4481 Ekind
(Typ
) = E_String_Literal_Subtype
4483 (Is_OK_Static_Subtype
(Component_Type
(Typ
))
4484 and then Is_OK_Static_Subtype
(Etype
(First_Index
(Typ
))));
4488 elsif Is_Scalar_Type
(Typ
) then
4489 if Base_T
= Typ
then
4493 -- Scalar_Range (Typ) might be an N_Subtype_Indication, so use
4494 -- Get_Type_{Low,High}_Bound.
4496 return Is_OK_Static_Subtype
(Anc_Subt
)
4497 and then Is_OK_Static_Expression
(Type_Low_Bound
(Typ
))
4498 and then Is_OK_Static_Expression
(Type_High_Bound
(Typ
));
4501 -- Types other than string and scalar types are never static
4506 end Is_OK_Static_Subtype
;
4508 ---------------------
4509 -- Is_Out_Of_Range --
4510 ---------------------
4512 function Is_Out_Of_Range
4515 Assume_Valid
: Boolean := False;
4516 Fixed_Int
: Boolean := False;
4517 Int_Real
: Boolean := False) return Boolean
4520 return Test_In_Range
(N
, Typ
, Assume_Valid
, Fixed_Int
, Int_Real
)
4522 end Is_Out_Of_Range
;
4524 ---------------------
4525 -- Is_Static_Range --
4526 ---------------------
4528 -- A static range is a range whose bounds are static expressions, or a
4529 -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)).
4530 -- We have already converted range attribute references, so we get the
4531 -- "or" part of this rule without needing a special test.
4533 function Is_Static_Range
(N
: Node_Id
) return Boolean is
4535 return Is_Static_Expression
(Low_Bound
(N
))
4536 and then Is_Static_Expression
(High_Bound
(N
));
4537 end Is_Static_Range
;
4539 -----------------------
4540 -- Is_Static_Subtype --
4541 -----------------------
4543 -- Determines if Typ is a static subtype as defined in (RM 4.9(26))
4545 function Is_Static_Subtype
(Typ
: Entity_Id
) return Boolean is
4546 Base_T
: constant Entity_Id
:= Base_Type
(Typ
);
4547 Anc_Subt
: Entity_Id
;
4550 -- First a quick check on the non static subtype flag. As described
4551 -- in further detail in Einfo, this flag is not decisive in all cases,
4552 -- but if it is set, then the subtype is definitely non-static.
4554 if Is_Non_Static_Subtype
(Typ
) then
4558 Anc_Subt
:= Ancestor_Subtype
(Typ
);
4560 if Anc_Subt
= Empty
then
4564 if Is_Generic_Type
(Root_Type
(Base_T
))
4565 or else Is_Generic_Actual_Type
(Base_T
)
4571 elsif Is_String_Type
(Typ
) then
4573 Ekind
(Typ
) = E_String_Literal_Subtype
4574 or else (Is_Static_Subtype
(Component_Type
(Typ
))
4575 and then Is_Static_Subtype
(Etype
(First_Index
(Typ
))));
4579 elsif Is_Scalar_Type
(Typ
) then
4580 if Base_T
= Typ
then
4584 return Is_Static_Subtype
(Anc_Subt
)
4585 and then Is_Static_Expression
(Type_Low_Bound
(Typ
))
4586 and then Is_Static_Expression
(Type_High_Bound
(Typ
));
4589 -- Types other than string and scalar types are never static
4594 end Is_Static_Subtype
;
4596 --------------------
4597 -- Not_Null_Range --
4598 --------------------
4600 function Not_Null_Range
(Lo
: Node_Id
; Hi
: Node_Id
) return Boolean is
4601 Typ
: constant Entity_Id
:= Etype
(Lo
);
4604 if not Compile_Time_Known_Value
(Lo
)
4605 or else not Compile_Time_Known_Value
(Hi
)
4610 if Is_Discrete_Type
(Typ
) then
4611 return Expr_Value
(Lo
) <= Expr_Value
(Hi
);
4614 pragma Assert
(Is_Real_Type
(Typ
));
4616 return Expr_Value_R
(Lo
) <= Expr_Value_R
(Hi
);
4624 function OK_Bits
(N
: Node_Id
; Bits
: Uint
) return Boolean is
4626 -- We allow a maximum of 500,000 bits which seems a reasonable limit
4628 if Bits
< 500_000
then
4632 Error_Msg_N
("static value too large, capacity exceeded", N
);
4641 procedure Out_Of_Range
(N
: Node_Id
) is
4643 -- If we have the static expression case, then this is an illegality
4644 -- in Ada 95 mode, except that in an instance, we never generate an
4645 -- error (if the error is legitimate, it was already diagnosed in the
4646 -- template). The expression to compute the length of a packed array is
4647 -- attached to the array type itself, and deserves a separate message.
4649 if Is_Static_Expression
(N
)
4650 and then not In_Instance
4651 and then not In_Inlined_Body
4652 and then Ada_Version
>= Ada_95
4654 if Nkind
(Parent
(N
)) = N_Defining_Identifier
4655 and then Is_Array_Type
(Parent
(N
))
4656 and then Present
(Packed_Array_Type
(Parent
(N
)))
4657 and then Present
(First_Rep_Item
(Parent
(N
)))
4660 ("length of packed array must not exceed Integer''Last",
4661 First_Rep_Item
(Parent
(N
)));
4662 Rewrite
(N
, Make_Integer_Literal
(Sloc
(N
), Uint_1
));
4665 Apply_Compile_Time_Constraint_Error
4666 (N
, "value not in range of}", CE_Range_Check_Failed
);
4669 -- Here we generate a warning for the Ada 83 case, or when we are in an
4670 -- instance, or when we have a non-static expression case.
4673 Apply_Compile_Time_Constraint_Error
4674 (N
, "value not in range of}??", CE_Range_Check_Failed
);
4678 -------------------------
4679 -- Rewrite_In_Raise_CE --
4680 -------------------------
4682 procedure Rewrite_In_Raise_CE
(N
: Node_Id
; Exp
: Node_Id
) is
4683 Typ
: constant Entity_Id
:= Etype
(N
);
4686 -- If we want to raise CE in the condition of a N_Raise_CE node
4687 -- we may as well get rid of the condition.
4689 if Present
(Parent
(N
))
4690 and then Nkind
(Parent
(N
)) = N_Raise_Constraint_Error
4692 Set_Condition
(Parent
(N
), Empty
);
4694 -- If the expression raising CE is a N_Raise_CE node, we can use that
4695 -- one. We just preserve the type of the context.
4697 elsif Nkind
(Exp
) = N_Raise_Constraint_Error
then
4701 -- Else build an explcit N_Raise_CE
4705 Make_Raise_Constraint_Error
(Sloc
(Exp
),
4706 Reason
=> CE_Range_Check_Failed
));
4707 Set_Raises_Constraint_Error
(N
);
4710 end Rewrite_In_Raise_CE
;
4712 ---------------------
4713 -- String_Type_Len --
4714 ---------------------
4716 function String_Type_Len
(Stype
: Entity_Id
) return Uint
is
4717 NT
: constant Entity_Id
:= Etype
(First_Index
(Stype
));
4721 if Is_OK_Static_Subtype
(NT
) then
4724 T
:= Base_Type
(NT
);
4727 return Expr_Value
(Type_High_Bound
(T
)) -
4728 Expr_Value
(Type_Low_Bound
(T
)) + 1;
4729 end String_Type_Len
;
4731 ------------------------------------
4732 -- Subtypes_Statically_Compatible --
4733 ------------------------------------
4735 function Subtypes_Statically_Compatible
4737 T2
: Entity_Id
) return Boolean
4742 if Is_Scalar_Type
(T1
) then
4744 -- Definitely compatible if we match
4746 if Subtypes_Statically_Match
(T1
, T2
) then
4749 -- If either subtype is nonstatic then they're not compatible
4751 elsif not Is_Static_Subtype
(T1
)
4752 or else not Is_Static_Subtype
(T2
)
4756 -- If either type has constraint error bounds, then consider that
4757 -- they match to avoid junk cascaded errors here.
4759 elsif not Is_OK_Static_Subtype
(T1
)
4760 or else not Is_OK_Static_Subtype
(T2
)
4764 -- Base types must match, but we don't check that (should we???) but
4765 -- we do at least check that both types are real, or both types are
4768 elsif Is_Real_Type
(T1
) /= Is_Real_Type
(T2
) then
4771 -- Here we check the bounds
4775 LB1
: constant Node_Id
:= Type_Low_Bound
(T1
);
4776 HB1
: constant Node_Id
:= Type_High_Bound
(T1
);
4777 LB2
: constant Node_Id
:= Type_Low_Bound
(T2
);
4778 HB2
: constant Node_Id
:= Type_High_Bound
(T2
);
4781 if Is_Real_Type
(T1
) then
4783 (Expr_Value_R
(LB1
) > Expr_Value_R
(HB1
))
4785 (Expr_Value_R
(LB2
) <= Expr_Value_R
(LB1
)
4787 Expr_Value_R
(HB1
) <= Expr_Value_R
(HB2
));
4791 (Expr_Value
(LB1
) > Expr_Value
(HB1
))
4793 (Expr_Value
(LB2
) <= Expr_Value
(LB1
)
4795 Expr_Value
(HB1
) <= Expr_Value
(HB2
));
4802 elsif Is_Access_Type
(T1
) then
4803 return (not Is_Constrained
(T2
)
4804 or else (Subtypes_Statically_Match
4805 (Designated_Type
(T1
), Designated_Type
(T2
))))
4806 and then not (Can_Never_Be_Null
(T2
)
4807 and then not Can_Never_Be_Null
(T1
));
4812 return (Is_Composite_Type
(T1
) and then not Is_Constrained
(T2
))
4813 or else Subtypes_Statically_Match
(T1
, T2
);
4815 end Subtypes_Statically_Compatible
;
4817 -------------------------------
4818 -- Subtypes_Statically_Match --
4819 -------------------------------
4821 -- Subtypes statically match if they have statically matching constraints
4822 -- (RM 4.9.1(2)). Constraints statically match if there are none, or if
4823 -- they are the same identical constraint, or if they are static and the
4824 -- values match (RM 4.9.1(1)).
4826 function Subtypes_Statically_Match
(T1
, T2
: Entity_Id
) return Boolean is
4828 function Predicates_Match
return Boolean;
4829 -- In Ada 2012, subtypes statically match if their static predicates
4832 ----------------------
4833 -- Predicates_Match --
4834 ----------------------
4836 function Predicates_Match
return Boolean is
4841 if Ada_Version
< Ada_2012
then
4844 elsif Has_Predicates
(T1
) /= Has_Predicates
(T2
) then
4850 (T1
, Name_Static_Predicate
, Check_Parents
=> False);
4853 (T2
, Name_Static_Predicate
, Check_Parents
=> False);
4855 -- Subtypes statically match if the predicate comes from the
4856 -- same declaration, which can only happen if one is a subtype
4857 -- of the other and has no explicit predicate.
4859 -- Suppress warnings on order of actuals, which is otherwise
4860 -- triggered by one of the two calls below.
4862 pragma Warnings
(Off
);
4863 return Pred1
= Pred2
4864 or else (No
(Pred1
) and then Is_Subtype_Of
(T1
, T2
))
4865 or else (No
(Pred2
) and then Is_Subtype_Of
(T2
, T1
));
4866 pragma Warnings
(On
);
4868 end Predicates_Match
;
4870 -- Start of processing for Subtypes_Statically_Match
4873 -- A type always statically matches itself
4880 elsif Is_Scalar_Type
(T1
) then
4882 -- Base types must be the same
4884 if Base_Type
(T1
) /= Base_Type
(T2
) then
4888 -- A constrained numeric subtype never matches an unconstrained
4889 -- subtype, i.e. both types must be constrained or unconstrained.
4891 -- To understand the requirement for this test, see RM 4.9.1(1).
4892 -- As is made clear in RM 3.5.4(11), type Integer, for example is
4893 -- a constrained subtype with constraint bounds matching the bounds
4894 -- of its corresponding unconstrained base type. In this situation,
4895 -- Integer and Integer'Base do not statically match, even though
4896 -- they have the same bounds.
4898 -- We only apply this test to types in Standard and types that appear
4899 -- in user programs. That way, we do not have to be too careful about
4900 -- setting Is_Constrained right for Itypes.
4902 if Is_Numeric_Type
(T1
)
4903 and then (Is_Constrained
(T1
) /= Is_Constrained
(T2
))
4904 and then (Scope
(T1
) = Standard_Standard
4905 or else Comes_From_Source
(T1
))
4906 and then (Scope
(T2
) = Standard_Standard
4907 or else Comes_From_Source
(T2
))
4911 -- A generic scalar type does not statically match its base type
4912 -- (AI-311). In this case we make sure that the formals, which are
4913 -- first subtypes of their bases, are constrained.
4915 elsif Is_Generic_Type
(T1
)
4916 and then Is_Generic_Type
(T2
)
4917 and then (Is_Constrained
(T1
) /= Is_Constrained
(T2
))
4922 -- If there was an error in either range, then just assume the types
4923 -- statically match to avoid further junk errors.
4925 if No
(Scalar_Range
(T1
)) or else No
(Scalar_Range
(T2
))
4926 or else Error_Posted
(Scalar_Range
(T1
))
4927 or else Error_Posted
(Scalar_Range
(T2
))
4932 -- Otherwise both types have bound that can be compared
4935 LB1
: constant Node_Id
:= Type_Low_Bound
(T1
);
4936 HB1
: constant Node_Id
:= Type_High_Bound
(T1
);
4937 LB2
: constant Node_Id
:= Type_Low_Bound
(T2
);
4938 HB2
: constant Node_Id
:= Type_High_Bound
(T2
);
4941 -- If the bounds are the same tree node, then match if and only
4942 -- if any predicates present also match.
4944 if LB1
= LB2
and then HB1
= HB2
then
4945 return Predicates_Match
;
4947 -- Otherwise bounds must be static and identical value
4950 if not Is_Static_Subtype
(T1
)
4951 or else not Is_Static_Subtype
(T2
)
4955 -- If either type has constraint error bounds, then say that
4956 -- they match to avoid junk cascaded errors here.
4958 elsif not Is_OK_Static_Subtype
(T1
)
4959 or else not Is_OK_Static_Subtype
(T2
)
4963 elsif Is_Real_Type
(T1
) then
4965 (Expr_Value_R
(LB1
) = Expr_Value_R
(LB2
))
4967 (Expr_Value_R
(HB1
) = Expr_Value_R
(HB2
));
4971 Expr_Value
(LB1
) = Expr_Value
(LB2
)
4973 Expr_Value
(HB1
) = Expr_Value
(HB2
);
4978 -- Type with discriminants
4980 elsif Has_Discriminants
(T1
) or else Has_Discriminants
(T2
) then
4982 -- Because of view exchanges in multiple instantiations, conformance
4983 -- checking might try to match a partial view of a type with no
4984 -- discriminants with a full view that has defaulted discriminants.
4985 -- In such a case, use the discriminant constraint of the full view,
4986 -- which must exist because we know that the two subtypes have the
4989 if Has_Discriminants
(T1
) /= Has_Discriminants
(T2
) then
4991 if Is_Private_Type
(T2
)
4992 and then Present
(Full_View
(T2
))
4993 and then Has_Discriminants
(Full_View
(T2
))
4995 return Subtypes_Statically_Match
(T1
, Full_View
(T2
));
4997 elsif Is_Private_Type
(T1
)
4998 and then Present
(Full_View
(T1
))
4999 and then Has_Discriminants
(Full_View
(T1
))
5001 return Subtypes_Statically_Match
(Full_View
(T1
), T2
);
5012 DL1
: constant Elist_Id
:= Discriminant_Constraint
(T1
);
5013 DL2
: constant Elist_Id
:= Discriminant_Constraint
(T2
);
5021 elsif Is_Constrained
(T1
) /= Is_Constrained
(T2
) then
5025 -- Now loop through the discriminant constraints
5027 -- Note: the guard here seems necessary, since it is possible at
5028 -- least for DL1 to be No_Elist. Not clear this is reasonable ???
5030 if Present
(DL1
) and then Present
(DL2
) then
5031 DA1
:= First_Elmt
(DL1
);
5032 DA2
:= First_Elmt
(DL2
);
5033 while Present
(DA1
) loop
5035 Expr1
: constant Node_Id
:= Node
(DA1
);
5036 Expr2
: constant Node_Id
:= Node
(DA2
);
5039 if not Is_Static_Expression
(Expr1
)
5040 or else not Is_Static_Expression
(Expr2
)
5044 -- If either expression raised a constraint error,
5045 -- consider the expressions as matching, since this
5046 -- helps to prevent cascading errors.
5048 elsif Raises_Constraint_Error
(Expr1
)
5049 or else Raises_Constraint_Error
(Expr2
)
5053 elsif Expr_Value
(Expr1
) /= Expr_Value
(Expr2
) then
5066 -- A definite type does not match an indefinite or classwide type.
5067 -- However, a generic type with unknown discriminants may be
5068 -- instantiated with a type with no discriminants, and conformance
5069 -- checking on an inherited operation may compare the actual with the
5070 -- subtype that renames it in the instance.
5073 Has_Unknown_Discriminants
(T1
) /= Has_Unknown_Discriminants
(T2
)
5076 Is_Generic_Actual_Type
(T1
) or else Is_Generic_Actual_Type
(T2
);
5080 elsif Is_Array_Type
(T1
) then
5082 -- If either subtype is unconstrained then both must be, and if both
5083 -- are unconstrained then no further checking is needed.
5085 if not Is_Constrained
(T1
) or else not Is_Constrained
(T2
) then
5086 return not (Is_Constrained
(T1
) or else Is_Constrained
(T2
));
5089 -- Both subtypes are constrained, so check that the index subtypes
5090 -- statically match.
5093 Index1
: Node_Id
:= First_Index
(T1
);
5094 Index2
: Node_Id
:= First_Index
(T2
);
5097 while Present
(Index1
) loop
5099 Subtypes_Statically_Match
(Etype
(Index1
), Etype
(Index2
))
5104 Next_Index
(Index1
);
5105 Next_Index
(Index2
);
5111 elsif Is_Access_Type
(T1
) then
5112 if Can_Never_Be_Null
(T1
) /= Can_Never_Be_Null
(T2
) then
5115 elsif Ekind_In
(T1
, E_Access_Subprogram_Type
,
5116 E_Anonymous_Access_Subprogram_Type
)
5120 (Designated_Type
(T1
),
5121 Designated_Type
(T2
));
5124 Subtypes_Statically_Match
5125 (Designated_Type
(T1
),
5126 Designated_Type
(T2
))
5127 and then Is_Access_Constant
(T1
) = Is_Access_Constant
(T2
);
5130 -- All other types definitely match
5135 end Subtypes_Statically_Match
;
5141 function Test
(Cond
: Boolean) return Uint
is
5150 ---------------------------------
5151 -- Test_Expression_Is_Foldable --
5152 ---------------------------------
5156 procedure Test_Expression_Is_Foldable
5166 if Debug_Flag_Dot_F
and then In_Extended_Main_Source_Unit
(N
) then
5170 -- If operand is Any_Type, just propagate to result and do not
5171 -- try to fold, this prevents cascaded errors.
5173 if Etype
(Op1
) = Any_Type
then
5174 Set_Etype
(N
, Any_Type
);
5177 -- If operand raises constraint error, then replace node N with the
5178 -- raise constraint error node, and we are obviously not foldable.
5179 -- Note that this replacement inherits the Is_Static_Expression flag
5180 -- from the operand.
5182 elsif Raises_Constraint_Error
(Op1
) then
5183 Rewrite_In_Raise_CE
(N
, Op1
);
5186 -- If the operand is not static, then the result is not static, and
5187 -- all we have to do is to check the operand since it is now known
5188 -- to appear in a non-static context.
5190 elsif not Is_Static_Expression
(Op1
) then
5191 Check_Non_Static_Context
(Op1
);
5192 Fold
:= Compile_Time_Known_Value
(Op1
);
5195 -- An expression of a formal modular type is not foldable because
5196 -- the modulus is unknown.
5198 elsif Is_Modular_Integer_Type
(Etype
(Op1
))
5199 and then Is_Generic_Type
(Etype
(Op1
))
5201 Check_Non_Static_Context
(Op1
);
5204 -- Here we have the case of an operand whose type is OK, which is
5205 -- static, and which does not raise constraint error, we can fold.
5208 Set_Is_Static_Expression
(N
);
5212 end Test_Expression_Is_Foldable
;
5216 procedure Test_Expression_Is_Foldable
5222 CRT_Safe
: Boolean := False)
5224 Rstat
: constant Boolean := Is_Static_Expression
(Op1
)
5225 and then Is_Static_Expression
(Op2
);
5231 -- Inhibit folding if -gnatd.f flag set
5233 if Debug_Flag_Dot_F
and then In_Extended_Main_Source_Unit
(N
) then
5237 -- If either operand is Any_Type, just propagate to result and
5238 -- do not try to fold, this prevents cascaded errors.
5240 if Etype
(Op1
) = Any_Type
or else Etype
(Op2
) = Any_Type
then
5241 Set_Etype
(N
, Any_Type
);
5244 -- If left operand raises constraint error, then replace node N with the
5245 -- Raise_Constraint_Error node, and we are obviously not foldable.
5246 -- Is_Static_Expression is set from the two operands in the normal way,
5247 -- and we check the right operand if it is in a non-static context.
5249 elsif Raises_Constraint_Error
(Op1
) then
5251 Check_Non_Static_Context
(Op2
);
5254 Rewrite_In_Raise_CE
(N
, Op1
);
5255 Set_Is_Static_Expression
(N
, Rstat
);
5258 -- Similar processing for the case of the right operand. Note that we
5259 -- don't use this routine for the short-circuit case, so we do not have
5260 -- to worry about that special case here.
5262 elsif Raises_Constraint_Error
(Op2
) then
5264 Check_Non_Static_Context
(Op1
);
5267 Rewrite_In_Raise_CE
(N
, Op2
);
5268 Set_Is_Static_Expression
(N
, Rstat
);
5271 -- Exclude expressions of a generic modular type, as above
5273 elsif Is_Modular_Integer_Type
(Etype
(Op1
))
5274 and then Is_Generic_Type
(Etype
(Op1
))
5276 Check_Non_Static_Context
(Op1
);
5279 -- If result is not static, then check non-static contexts on operands
5280 -- since one of them may be static and the other one may not be static.
5282 elsif not Rstat
then
5283 Check_Non_Static_Context
(Op1
);
5284 Check_Non_Static_Context
(Op2
);
5287 Fold
:= CRT_Safe_Compile_Time_Known_Value
(Op1
)
5288 and then CRT_Safe_Compile_Time_Known_Value
(Op2
);
5290 Fold
:= Compile_Time_Known_Value
(Op1
)
5291 and then Compile_Time_Known_Value
(Op2
);
5296 -- Else result is static and foldable. Both operands are static, and
5297 -- neither raises constraint error, so we can definitely fold.
5300 Set_Is_Static_Expression
(N
);
5305 end Test_Expression_Is_Foldable
;
5311 function Test_In_Range
5314 Assume_Valid
: Boolean;
5315 Fixed_Int
: Boolean;
5316 Int_Real
: Boolean) return Range_Membership
5321 pragma Warnings
(Off
, Assume_Valid
);
5322 -- For now Assume_Valid is unreferenced since the current implementation
5323 -- always returns Unknown if N is not a compile time known value, but we
5324 -- keep the parameter to allow for future enhancements in which we try
5325 -- to get the information in the variable case as well.
5328 -- Universal types have no range limits, so always in range
5330 if Typ
= Universal_Integer
or else Typ
= Universal_Real
then
5333 -- Never known if not scalar type. Don't know if this can actually
5334 -- happen, but our spec allows it, so we must check.
5336 elsif not Is_Scalar_Type
(Typ
) then
5339 -- Never known if this is a generic type, since the bounds of generic
5340 -- types are junk. Note that if we only checked for static expressions
5341 -- (instead of compile time known values) below, we would not need this
5342 -- check, because values of a generic type can never be static, but they
5343 -- can be known at compile time.
5345 elsif Is_Generic_Type
(Typ
) then
5348 -- Never known unless we have a compile time known value
5350 elsif not Compile_Time_Known_Value
(N
) then
5353 -- General processing with a known compile time value
5364 Lo
:= Type_Low_Bound
(Typ
);
5365 Hi
:= Type_High_Bound
(Typ
);
5367 LB_Known
:= Compile_Time_Known_Value
(Lo
);
5368 HB_Known
:= Compile_Time_Known_Value
(Hi
);
5370 -- Fixed point types should be considered as such only if flag
5371 -- Fixed_Int is set to False.
5373 if Is_Floating_Point_Type
(Typ
)
5374 or else (Is_Fixed_Point_Type
(Typ
) and then not Fixed_Int
)
5377 Valr
:= Expr_Value_R
(N
);
5379 if LB_Known
and HB_Known
then
5380 if Valr
>= Expr_Value_R
(Lo
)
5382 Valr
<= Expr_Value_R
(Hi
)
5386 return Out_Of_Range
;
5389 elsif (LB_Known
and then Valr
< Expr_Value_R
(Lo
))
5391 (HB_Known
and then Valr
> Expr_Value_R
(Hi
))
5393 return Out_Of_Range
;
5400 Val
:= Expr_Value
(N
);
5402 if LB_Known
and HB_Known
then
5403 if Val
>= Expr_Value
(Lo
)
5405 Val
<= Expr_Value
(Hi
)
5409 return Out_Of_Range
;
5412 elsif (LB_Known
and then Val
< Expr_Value
(Lo
))
5414 (HB_Known
and then Val
> Expr_Value
(Hi
))
5416 return Out_Of_Range
;
5430 procedure To_Bits
(U
: Uint
; B
: out Bits
) is
5432 for J
in 0 .. B
'Last loop
5433 B
(J
) := (U
/ (2 ** J
)) mod 2 /= 0;
5437 --------------------
5438 -- Why_Not_Static --
5439 --------------------
5441 procedure Why_Not_Static
(Expr
: Node_Id
) is
5442 N
: constant Node_Id
:= Original_Node
(Expr
);
5446 procedure Why_Not_Static_List
(L
: List_Id
);
5447 -- A version that can be called on a list of expressions. Finds all
5448 -- non-static violations in any element of the list.
5450 -------------------------
5451 -- Why_Not_Static_List --
5452 -------------------------
5454 procedure Why_Not_Static_List
(L
: List_Id
) is
5458 if Is_Non_Empty_List
(L
) then
5460 while Present
(N
) loop
5465 end Why_Not_Static_List
;
5467 -- Start of processing for Why_Not_Static
5470 -- If in ACATS mode (debug flag 2), then suppress all these messages,
5471 -- this avoids massive updates to the ACATS base line.
5473 if Debug_Flag_2
then
5477 -- Ignore call on error or empty node
5479 if No
(Expr
) or else Nkind
(Expr
) = N_Error
then
5483 -- Preprocessing for sub expressions
5485 if Nkind
(Expr
) in N_Subexpr
then
5487 -- Nothing to do if expression is static
5489 if Is_OK_Static_Expression
(Expr
) then
5493 -- Test for constraint error raised
5495 if Raises_Constraint_Error
(Expr
) then
5497 ("\expression raises exception, cannot be static " &
5502 -- If no type, then something is pretty wrong, so ignore
5504 Typ
:= Etype
(Expr
);
5510 -- Type must be scalar or string type (but allow Bignum, since this
5511 -- is really a scalar type from our point of view in this diagnosis).
5513 if not Is_Scalar_Type
(Typ
)
5514 and then not Is_String_Type
(Typ
)
5515 and then not Is_RTE
(Typ
, RE_Bignum
)
5518 ("\static expression must have scalar or string type " &
5524 -- If we got through those checks, test particular node kind
5530 when N_Expanded_Name | N_Identifier | N_Operator_Symbol
=>
5533 if Is_Named_Number
(E
) then
5536 elsif Ekind
(E
) = E_Constant
then
5538 -- One case we can give a metter message is when we have a
5539 -- string literal created by concatenating an aggregate with
5540 -- an others expression.
5542 Entity_Case
: declare
5543 CV
: constant Node_Id
:= Constant_Value
(E
);
5544 CO
: constant Node_Id
:= Original_Node
(CV
);
5546 function Is_Aggregate
(N
: Node_Id
) return Boolean;
5547 -- See if node N came from an others aggregate, if so
5548 -- return True and set Error_Msg_Sloc to aggregate.
5554 function Is_Aggregate
(N
: Node_Id
) return Boolean is
5556 if Nkind
(Original_Node
(N
)) = N_Aggregate
then
5557 Error_Msg_Sloc
:= Sloc
(Original_Node
(N
));
5559 elsif Is_Entity_Name
(N
)
5560 and then Ekind
(Entity
(N
)) = E_Constant
5562 Nkind
(Original_Node
(Constant_Value
(Entity
(N
)))) =
5566 Sloc
(Original_Node
(Constant_Value
(Entity
(N
))));
5573 -- Start of processing for Entity_Case
5576 if Is_Aggregate
(CV
)
5577 or else (Nkind
(CO
) = N_Op_Concat
5578 and then (Is_Aggregate
(Left_Opnd
(CO
))
5580 Is_Aggregate
(Right_Opnd
(CO
))))
5582 Error_Msg_N
("\aggregate (#) is never static", N
);
5584 elsif No
(CV
) or else not Is_Static_Expression
(CV
) then
5586 ("\& is not a static constant (RM 4.9(5))", N
, E
);
5592 ("\& is not static constant or named number "
5593 & "(RM 4.9(5))", N
, E
);
5598 when N_Binary_Op | N_Short_Circuit | N_Membership_Test
=>
5599 if Nkind
(N
) in N_Op_Shift
then
5601 ("\shift functions are never static (RM 4.9(6,18))", N
);
5604 Why_Not_Static
(Left_Opnd
(N
));
5605 Why_Not_Static
(Right_Opnd
(N
));
5611 Why_Not_Static
(Right_Opnd
(N
));
5613 -- Attribute reference
5615 when N_Attribute_Reference
=>
5616 Why_Not_Static_List
(Expressions
(N
));
5618 E
:= Etype
(Prefix
(N
));
5620 if E
= Standard_Void_Type
then
5624 -- Special case non-scalar'Size since this is a common error
5626 if Attribute_Name
(N
) = Name_Size
then
5628 ("\size attribute is only static for static scalar type "
5629 & "(RM 4.9(7,8))", N
);
5633 elsif Is_Array_Type
(E
) then
5634 if Attribute_Name
(N
) /= Name_First
5636 Attribute_Name
(N
) /= Name_Last
5638 Attribute_Name
(N
) /= Name_Length
5641 ("\static array attribute must be Length, First, or Last "
5642 & "(RM 4.9(8))", N
);
5644 -- Since we know the expression is not-static (we already
5645 -- tested for this, must mean array is not static).
5649 ("\prefix is non-static array (RM 4.9(8))", Prefix
(N
));
5654 -- Special case generic types, since again this is a common source
5657 elsif Is_Generic_Actual_Type
(E
)
5662 ("\attribute of generic type is never static "
5663 & "(RM 4.9(7,8))", N
);
5665 elsif Is_Static_Subtype
(E
) then
5668 elsif Is_Scalar_Type
(E
) then
5670 ("\prefix type for attribute is not static scalar subtype "
5671 & "(RM 4.9(7))", N
);
5675 ("\static attribute must apply to array/scalar type "
5676 & "(RM 4.9(7,8))", N
);
5681 when N_String_Literal
=>
5683 ("\subtype of string literal is non-static (RM 4.9(4))", N
);
5685 -- Explicit dereference
5687 when N_Explicit_Dereference
=>
5689 ("\explicit dereference is never static (RM 4.9)", N
);
5693 when N_Function_Call
=>
5694 Why_Not_Static_List
(Parameter_Associations
(N
));
5696 -- Complain about non-static function call unless we have Bignum
5697 -- which means that the underlying expression is really some
5698 -- scalar arithmetic operation.
5700 if not Is_RTE
(Typ
, RE_Bignum
) then
5701 Error_Msg_N
("\non-static function call (RM 4.9(6,18))", N
);
5704 -- Parameter assocation (test actual parameter)
5706 when N_Parameter_Association
=>
5707 Why_Not_Static
(Explicit_Actual_Parameter
(N
));
5709 -- Indexed component
5711 when N_Indexed_Component
=>
5712 Error_Msg_N
("\indexed component is never static (RM 4.9)", N
);
5716 when N_Procedure_Call_Statement
=>
5717 Error_Msg_N
("\procedure call is never static (RM 4.9)", N
);
5719 -- Qualified expression (test expression)
5721 when N_Qualified_Expression
=>
5722 Why_Not_Static
(Expression
(N
));
5726 when N_Aggregate | N_Extension_Aggregate
=>
5727 Error_Msg_N
("\an aggregate is never static (RM 4.9)", N
);
5732 Why_Not_Static
(Low_Bound
(N
));
5733 Why_Not_Static
(High_Bound
(N
));
5735 -- Range constraint, test range expression
5737 when N_Range_Constraint
=>
5738 Why_Not_Static
(Range_Expression
(N
));
5740 -- Subtype indication, test constraint
5742 when N_Subtype_Indication
=>
5743 Why_Not_Static
(Constraint
(N
));
5745 -- Selected component
5747 when N_Selected_Component
=>
5748 Error_Msg_N
("\selected component is never static (RM 4.9)", N
);
5753 Error_Msg_N
("\slice is never static (RM 4.9)", N
);
5755 when N_Type_Conversion
=>
5756 Why_Not_Static
(Expression
(N
));
5758 if not Is_Scalar_Type
(Entity
(Subtype_Mark
(N
)))
5759 or else not Is_Static_Subtype
(Entity
(Subtype_Mark
(N
)))
5762 ("\static conversion requires static scalar subtype result "
5763 & "(RM 4.9(9))", N
);
5766 -- Unchecked type conversion
5768 when N_Unchecked_Type_Conversion
=>
5770 ("\unchecked type conversion is never static (RM 4.9)", N
);
5772 -- All other cases, no reason to give