1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2008, 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 Ada.Characters.Latin_1; use Ada.Characters.Latin_1;
28 with Atree; use Atree;
29 with Casing; use Casing;
30 with Checks; use Checks;
31 with Einfo; use Einfo;
32 with Errout; use Errout;
34 with Exp_Dist; use Exp_Dist;
35 with Exp_Util; use Exp_Util;
36 with Expander; use Expander;
37 with Freeze; use Freeze;
38 with Itypes; use Itypes;
40 with Lib.Xref; use Lib.Xref;
41 with Nlists; use Nlists;
42 with Nmake; use Nmake;
44 with Restrict; use Restrict;
45 with Rident; use Rident;
46 with Rtsfind; use Rtsfind;
47 with Sdefault; use Sdefault;
49 with Sem_Aux; use Sem_Aux;
50 with Sem_Cat; use Sem_Cat;
51 with Sem_Ch6; use Sem_Ch6;
52 with Sem_Ch8; use Sem_Ch8;
53 with Sem_Dist; use Sem_Dist;
54 with Sem_Eval; use Sem_Eval;
55 with Sem_Res; use Sem_Res;
56 with Sem_Type; use Sem_Type;
57 with Sem_Util; use Sem_Util;
58 with Stand; use Stand;
59 with Sinfo; use Sinfo;
60 with Sinput; use Sinput;
61 with Stringt; use Stringt;
63 with Stylesw; use Stylesw;
64 with Targparm; use Targparm;
65 with Ttypes; use Ttypes;
66 with Ttypef; use Ttypef;
67 with Tbuild; use Tbuild;
68 with Uintp; use Uintp;
69 with Urealp; use Urealp;
71 package body Sem_Attr is
73 True_Value : constant Uint := Uint_1;
74 False_Value : constant Uint := Uint_0;
75 -- Synonyms to be used when these constants are used as Boolean values
77 Bad_Attribute : exception;
78 -- Exception raised if an error is detected during attribute processing,
79 -- used so that we can abandon the processing so we don't run into
80 -- trouble with cascaded errors.
82 -- The following array is the list of attributes defined in the Ada 83 RM
83 -- that are not included in Ada 95, but still get recognized in GNAT.
85 Attribute_83 : constant Attribute_Class_Array := Attribute_Class_Array'(
91 Attribute_Constrained |
104 Attribute_Leading_Part |
106 Attribute_Machine_Emax |
107 Attribute_Machine_Emin |
108 Attribute_Machine_Mantissa |
109 Attribute_Machine_Overflows |
110 Attribute_Machine_Radix |
111 Attribute_Machine_Rounds |
117 Attribute_Safe_Emax |
118 Attribute_Safe_Large |
119 Attribute_Safe_Small |
122 Attribute_Storage_Size |
124 Attribute_Terminated |
127 Attribute_Width => True,
130 -- The following array is the list of attributes defined in the Ada 2005
131 -- RM which are not defined in Ada 95. These are recognized in Ada 95 mode,
132 -- but in Ada 95 they are considered to be implementation defined.
134 Attribute_05 : constant Attribute_Class_Array := Attribute_Class_Array'(
135 Attribute_Machine_Rounding |
137 Attribute_Stream_Size |
138 Attribute_Wide_Wide_Width => True,
141 -- The following array contains all attributes that imply a modification
142 -- of their prefixes or result in an access value. Such prefixes can be
143 -- considered as lvalues.
145 Attribute_Name_Implies_Lvalue_Prefix : constant Attribute_Class_Array :=
146 Attribute_Class_Array'(
151 Attribute_Unchecked_Access |
152 Attribute_Unrestricted_Access => True,
155 -----------------------
156 -- Local_Subprograms --
157 -----------------------
159 procedure Eval_Attribute (N : Node_Id);
160 -- Performs compile time evaluation of attributes where possible, leaving
161 -- the Is_Static_Expression/Raises_Constraint_Error flags appropriately
162 -- set, and replacing the node with a literal node if the value can be
163 -- computed at compile time. All static attribute references are folded,
164 -- as well as a number of cases of non-static attributes that can always
165 -- be computed at compile time (e.g. floating-point model attributes that
166 -- are applied to non-static subtypes). Of course in such cases, the
167 -- Is_Static_Expression flag will not be set on the resulting literal.
168 -- Note that the only required action of this procedure is to catch the
169 -- static expression cases as described in the RM. Folding of other cases
170 -- is done where convenient, but some additional non-static folding is in
171 -- N_Expand_Attribute_Reference in cases where this is more convenient.
173 function Is_Anonymous_Tagged_Base
177 -- For derived tagged types that constrain parent discriminants we build
178 -- an anonymous unconstrained base type. We need to recognize the relation
179 -- between the two when analyzing an access attribute for a constrained
180 -- component, before the full declaration for Typ has been analyzed, and
181 -- where therefore the prefix of the attribute does not match the enclosing
184 -----------------------
185 -- Analyze_Attribute --
186 -----------------------
188 procedure Analyze_Attribute (N : Node_Id) is
189 Loc : constant Source_Ptr := Sloc (N);
190 Aname : constant Name_Id := Attribute_Name (N);
191 P : constant Node_Id := Prefix (N);
192 Exprs : constant List_Id := Expressions (N);
193 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
198 -- Type of prefix after analysis
200 P_Base_Type : Entity_Id;
201 -- Base type of prefix after analysis
203 -----------------------
204 -- Local Subprograms --
205 -----------------------
207 procedure Analyze_Access_Attribute;
208 -- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
209 -- Internally, Id distinguishes which of the three cases is involved.
211 procedure Check_Array_Or_Scalar_Type;
212 -- Common procedure used by First, Last, Range attribute to check
213 -- that the prefix is a constrained array or scalar type, or a name
214 -- of an array object, and that an argument appears only if appropriate
215 -- (i.e. only in the array case).
217 procedure Check_Array_Type;
218 -- Common semantic checks for all array attributes. Checks that the
219 -- prefix is a constrained array type or the name of an array object.
220 -- The error message for non-arrays is specialized appropriately.
222 procedure Check_Asm_Attribute;
223 -- Common semantic checks for Asm_Input and Asm_Output attributes
225 procedure Check_Component;
226 -- Common processing for Bit_Position, First_Bit, Last_Bit, and
227 -- Position. Checks prefix is an appropriate selected component.
229 procedure Check_Decimal_Fixed_Point_Type;
230 -- Check that prefix of attribute N is a decimal fixed-point type
232 procedure Check_Dereference;
233 -- If the prefix of attribute is an object of an access type, then
234 -- introduce an explicit deference, and adjust P_Type accordingly.
236 procedure Check_Discrete_Type;
237 -- Verify that prefix of attribute N is a discrete type
240 -- Check that no attribute arguments are present
242 procedure Check_Either_E0_Or_E1;
243 -- Check that there are zero or one attribute arguments present
246 -- Check that exactly one attribute argument is present
249 -- Check that two attribute arguments are present
251 procedure Check_Enum_Image;
252 -- If the prefix type is an enumeration type, set all its literals
253 -- as referenced, since the image function could possibly end up
254 -- referencing any of the literals indirectly. Same for Enum_Val.
256 procedure Check_Fixed_Point_Type;
257 -- Verify that prefix of attribute N is a fixed type
259 procedure Check_Fixed_Point_Type_0;
260 -- Verify that prefix of attribute N is a fixed type and that
261 -- no attribute expressions are present
263 procedure Check_Floating_Point_Type;
264 -- Verify that prefix of attribute N is a float type
266 procedure Check_Floating_Point_Type_0;
267 -- Verify that prefix of attribute N is a float type and that
268 -- no attribute expressions are present
270 procedure Check_Floating_Point_Type_1;
271 -- Verify that prefix of attribute N is a float type and that
272 -- exactly one attribute expression is present
274 procedure Check_Floating_Point_Type_2;
275 -- Verify that prefix of attribute N is a float type and that
276 -- two attribute expressions are present
278 procedure Legal_Formal_Attribute;
279 -- Common processing for attributes Definite and Has_Discriminants.
280 -- Checks that prefix is generic indefinite formal type.
282 procedure Check_Integer_Type;
283 -- Verify that prefix of attribute N is an integer type
285 procedure Check_Library_Unit;
286 -- Verify that prefix of attribute N is a library unit
288 procedure Check_Modular_Integer_Type;
289 -- Verify that prefix of attribute N is a modular integer type
291 procedure Check_Not_CPP_Type;
292 -- Check that P (the prefix of the attribute) is not an CPP type
293 -- for which no Ada predefined primitive is available.
295 procedure Check_Not_Incomplete_Type;
296 -- Check that P (the prefix of the attribute) is not an incomplete
297 -- type or a private type for which no full view has been given.
299 procedure Check_Object_Reference (P : Node_Id);
300 -- Check that P (the prefix of the attribute) is an object reference
302 procedure Check_Program_Unit;
303 -- Verify that prefix of attribute N is a program unit
305 procedure Check_Real_Type;
306 -- Verify that prefix of attribute N is fixed or float type
308 procedure Check_Scalar_Type;
309 -- Verify that prefix of attribute N is a scalar type
311 procedure Check_Standard_Prefix;
312 -- Verify that prefix of attribute N is package Standard
314 procedure Check_Stream_Attribute (Nam : TSS_Name_Type);
315 -- Validity checking for stream attribute. Nam is the TSS name of the
316 -- corresponding possible defined attribute function (e.g. for the
317 -- Read attribute, Nam will be TSS_Stream_Read).
319 procedure Check_PolyORB_Attribute;
320 -- Validity checking for PolyORB/DSA attribute
322 procedure Check_Task_Prefix;
323 -- Verify that prefix of attribute N is a task or task type
325 procedure Check_Type;
326 -- Verify that the prefix of attribute N is a type
328 procedure Check_Unit_Name (Nod : Node_Id);
329 -- Check that Nod is of the form of a library unit name, i.e that
330 -- it is an identifier, or a selected component whose prefix is
331 -- itself of the form of a library unit name. Note that this is
332 -- quite different from Check_Program_Unit, since it only checks
333 -- the syntactic form of the name, not the semantic identity. This
334 -- is because it is used with attributes (Elab_Body, Elab_Spec, and
335 -- UET_Address) which can refer to non-visible unit.
337 procedure Error_Attr (Msg : String; Error_Node : Node_Id);
338 pragma No_Return (Error_Attr);
339 procedure Error_Attr;
340 pragma No_Return (Error_Attr);
341 -- Posts error using Error_Msg_N at given node, sets type of attribute
342 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
343 -- semantic processing. The message typically contains a % insertion
344 -- character which is replaced by the attribute name. The call with
345 -- no arguments is used when the caller has already generated the
346 -- required error messages.
348 procedure Error_Attr_P (Msg : String);
349 pragma No_Return (Error_Attr);
350 -- Like Error_Attr, but error is posted at the start of the prefix
352 procedure Standard_Attribute (Val : Int);
353 -- Used to process attributes whose prefix is package Standard which
354 -- yield values of type Universal_Integer. The attribute reference
355 -- node is rewritten with an integer literal of the given value.
357 procedure Unexpected_Argument (En : Node_Id);
358 -- Signal unexpected attribute argument (En is the argument)
360 procedure Validate_Non_Static_Attribute_Function_Call;
361 -- Called when processing an attribute that is a function call to a
362 -- non-static function, i.e. an attribute function that either takes
363 -- non-scalar arguments or returns a non-scalar result. Verifies that
364 -- such a call does not appear in a preelaborable context.
366 ------------------------------
367 -- Analyze_Access_Attribute --
368 ------------------------------
370 procedure Analyze_Access_Attribute is
371 Acc_Type : Entity_Id;
376 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id;
377 -- Build an access-to-object type whose designated type is DT,
378 -- and whose Ekind is appropriate to the attribute type. The
379 -- type that is constructed is returned as the result.
381 procedure Build_Access_Subprogram_Type (P : Node_Id);
382 -- Build an access to subprogram whose designated type is the type of
383 -- the prefix. If prefix is overloaded, so is the node itself. The
384 -- result is stored in Acc_Type.
386 function OK_Self_Reference return Boolean;
387 -- An access reference whose prefix is a type can legally appear
388 -- within an aggregate, where it is obtained by expansion of
389 -- a defaulted aggregate. The enclosing aggregate that contains
390 -- the self-referenced is flagged so that the self-reference can
391 -- be expanded into a reference to the target object (see exp_aggr).
393 ------------------------------
394 -- Build_Access_Object_Type --
395 ------------------------------
397 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is
398 Typ : constant Entity_Id :=
400 (E_Access_Attribute_Type, Current_Scope, Loc, 'A');
402 Set_Etype (Typ, Typ);
404 Set_Associated_Node_For_Itype (Typ, N);
405 Set_Directly_Designated_Type (Typ, DT);
407 end Build_Access_Object_Type;
409 ----------------------------------
410 -- Build_Access_Subprogram_Type --
411 ----------------------------------
413 procedure Build_Access_Subprogram_Type (P : Node_Id) is
414 Index : Interp_Index;
417 procedure Check_Local_Access (E : Entity_Id);
418 -- Deal with possible access to local subprogram. If we have such
419 -- an access, we set a flag to kill all tracked values on any call
420 -- because this access value may be passed around, and any called
421 -- code might use it to access a local procedure which clobbers a
424 function Get_Kind (E : Entity_Id) return Entity_Kind;
425 -- Distinguish between access to regular/protected subprograms
427 ------------------------
428 -- Check_Local_Access --
429 ------------------------
431 procedure Check_Local_Access (E : Entity_Id) is
433 if not Is_Library_Level_Entity (E) then
434 Set_Suppress_Value_Tracking_On_Call (Current_Scope);
436 end Check_Local_Access;
442 function Get_Kind (E : Entity_Id) return Entity_Kind is
444 if Convention (E) = Convention_Protected then
445 return E_Access_Protected_Subprogram_Type;
447 return E_Access_Subprogram_Type;
451 -- Start of processing for Build_Access_Subprogram_Type
454 -- In the case of an access to subprogram, use the name of the
455 -- subprogram itself as the designated type. Type-checking in
456 -- this case compares the signatures of the designated types.
458 -- Note: This fragment of the tree is temporarily malformed
459 -- because the correct tree requires an E_Subprogram_Type entity
460 -- as the designated type. In most cases this designated type is
461 -- later overridden by the semantics with the type imposed by the
462 -- context during the resolution phase. In the specific case of
463 -- the expression Address!(Prim'Unrestricted_Access), used to
464 -- initialize slots of dispatch tables, this work will be done by
465 -- the expander (see Exp_Aggr).
467 -- The reason to temporarily add this kind of node to the tree
468 -- instead of a proper E_Subprogram_Type itype, is the following:
469 -- in case of errors found in the source file we report better
470 -- error messages. For example, instead of generating the
473 -- "expected access to subprogram with profile
474 -- defined at line X"
476 -- we currently generate:
478 -- "expected access to function Z defined at line X"
480 Set_Etype (N, Any_Type);
482 if not Is_Overloaded (P) then
483 Check_Local_Access (Entity (P));
485 if not Is_Intrinsic_Subprogram (Entity (P)) then
486 Acc_Type := Create_Itype (Get_Kind (Entity (P)), N);
487 Set_Is_Public (Acc_Type, False);
488 Set_Etype (Acc_Type, Acc_Type);
489 Set_Convention (Acc_Type, Convention (Entity (P)));
490 Set_Directly_Designated_Type (Acc_Type, Entity (P));
491 Set_Etype (N, Acc_Type);
492 Freeze_Before (N, Acc_Type);
496 Get_First_Interp (P, Index, It);
497 while Present (It.Nam) loop
498 Check_Local_Access (It.Nam);
500 if not Is_Intrinsic_Subprogram (It.Nam) then
501 Acc_Type := Create_Itype (Get_Kind (It.Nam), N);
502 Set_Is_Public (Acc_Type, False);
503 Set_Etype (Acc_Type, Acc_Type);
504 Set_Convention (Acc_Type, Convention (It.Nam));
505 Set_Directly_Designated_Type (Acc_Type, It.Nam);
506 Add_One_Interp (N, Acc_Type, Acc_Type);
507 Freeze_Before (N, Acc_Type);
510 Get_Next_Interp (Index, It);
514 -- Cannot be applied to intrinsic. Looking at the tests above,
515 -- the only way Etype (N) can still be set to Any_Type is if
516 -- Is_Intrinsic_Subprogram was True for some referenced entity.
518 if Etype (N) = Any_Type then
519 Error_Attr_P ("prefix of % attribute cannot be intrinsic");
521 end Build_Access_Subprogram_Type;
523 ----------------------
524 -- OK_Self_Reference --
525 ----------------------
527 function OK_Self_Reference return Boolean is
534 (Nkind (Par) = N_Component_Association
535 or else Nkind (Par) in N_Subexpr)
537 if Nkind_In (Par, N_Aggregate, N_Extension_Aggregate) then
538 if Etype (Par) = Typ then
539 Set_Has_Self_Reference (Par);
547 -- No enclosing aggregate, or not a self-reference
550 end OK_Self_Reference;
552 -- Start of processing for Analyze_Access_Attribute
557 if Nkind (P) = N_Character_Literal then
559 ("prefix of % attribute cannot be enumeration literal");
562 -- Case of access to subprogram
564 if Is_Entity_Name (P)
565 and then Is_Overloadable (Entity (P))
567 if Has_Pragma_Inline_Always (Entity (P)) then
569 ("prefix of % attribute cannot be Inline_Always subprogram");
572 if Aname = Name_Unchecked_Access then
573 Error_Attr ("attribute% cannot be applied to a subprogram", P);
576 -- Build the appropriate subprogram type
578 Build_Access_Subprogram_Type (P);
580 -- For unrestricted access, kill current values, since this
581 -- attribute allows a reference to a local subprogram that
582 -- could modify local variables to be passed out of scope
584 if Aname = Name_Unrestricted_Access then
586 -- Do not kill values on nodes initializing dispatch tables
587 -- slots. The construct Prim_Ptr!(Prim'Unrestricted_Access)
588 -- is currently generated by the expander only for this
589 -- purpose. Done to keep the quality of warnings currently
590 -- generated by the compiler (otherwise any declaration of
591 -- a tagged type cleans constant indications from its scope).
593 if Nkind (Parent (N)) = N_Unchecked_Type_Conversion
594 and then (Etype (Parent (N)) = RTE (RE_Prim_Ptr)
596 Etype (Parent (N)) = RTE (RE_Size_Ptr))
597 and then Is_Dispatching_Operation
598 (Directly_Designated_Type (Etype (N)))
608 -- Component is an operation of a protected type
610 elsif Nkind (P) = N_Selected_Component
611 and then Is_Overloadable (Entity (Selector_Name (P)))
613 if Ekind (Entity (Selector_Name (P))) = E_Entry then
614 Error_Attr_P ("prefix of % attribute must be subprogram");
617 Build_Access_Subprogram_Type (Selector_Name (P));
621 -- Deal with incorrect reference to a type, but note that some
622 -- accesses are allowed: references to the current type instance,
623 -- or in Ada 2005 self-referential pointer in a default-initialized
626 if Is_Entity_Name (P) then
629 -- The reference may appear in an aggregate that has been expanded
630 -- into a loop. Locate scope of type definition, if any.
632 Scop := Current_Scope;
633 while Ekind (Scop) = E_Loop loop
634 Scop := Scope (Scop);
637 if Is_Type (Typ) then
639 -- OK if we are within the scope of a limited type
640 -- let's mark the component as having per object constraint
642 if Is_Anonymous_Tagged_Base (Scop, Typ) then
650 Q : Node_Id := Parent (N);
654 and then Nkind (Q) /= N_Component_Declaration
660 Set_Has_Per_Object_Constraint (
661 Defining_Identifier (Q), True);
665 if Nkind (P) = N_Expanded_Name then
667 ("current instance prefix must be a direct name", P);
670 -- If a current instance attribute appears in a component
671 -- constraint it must appear alone; other contexts (spec-
672 -- expressions, within a task body) are not subject to this
675 if not In_Spec_Expression
676 and then not Has_Completion (Scop)
678 Nkind_In (Parent (N), N_Discriminant_Association,
679 N_Index_Or_Discriminant_Constraint)
682 ("current instance attribute must appear alone", N);
685 -- OK if we are in initialization procedure for the type
686 -- in question, in which case the reference to the type
687 -- is rewritten as a reference to the current object.
689 elsif Ekind (Scop) = E_Procedure
690 and then Is_Init_Proc (Scop)
691 and then Etype (First_Formal (Scop)) = Typ
694 Make_Attribute_Reference (Loc,
695 Prefix => Make_Identifier (Loc, Name_uInit),
696 Attribute_Name => Name_Unrestricted_Access));
700 -- OK if a task type, this test needs sharpening up ???
702 elsif Is_Task_Type (Typ) then
705 -- OK if self-reference in an aggregate in Ada 2005, and
706 -- the reference comes from a copied default expression.
708 -- Note that we check legality of self-reference even if the
709 -- expression comes from source, e.g. when a single component
710 -- association in an aggregate has a box association.
712 elsif Ada_Version >= Ada_05
713 and then OK_Self_Reference
717 -- OK if reference to current instance of a protected object
719 elsif Is_Protected_Self_Reference (P) then
722 -- Otherwise we have an error case
725 Error_Attr ("% attribute cannot be applied to type", P);
731 -- If we fall through, we have a normal access to object case.
732 -- Unrestricted_Access is legal wherever an allocator would be
733 -- legal, so its Etype is set to E_Allocator. The expected type
734 -- of the other attributes is a general access type, and therefore
735 -- we label them with E_Access_Attribute_Type.
737 if not Is_Overloaded (P) then
738 Acc_Type := Build_Access_Object_Type (P_Type);
739 Set_Etype (N, Acc_Type);
742 Index : Interp_Index;
745 Set_Etype (N, Any_Type);
746 Get_First_Interp (P, Index, It);
747 while Present (It.Typ) loop
748 Acc_Type := Build_Access_Object_Type (It.Typ);
749 Add_One_Interp (N, Acc_Type, Acc_Type);
750 Get_Next_Interp (Index, It);
755 -- Special cases when we can find a prefix that is an entity name
764 if Is_Entity_Name (PP) then
767 -- If we have an access to an object, and the attribute
768 -- comes from source, then set the object as potentially
769 -- source modified. We do this because the resulting access
770 -- pointer can be used to modify the variable, and we might
771 -- not detect this, leading to some junk warnings.
773 Set_Never_Set_In_Source (Ent, False);
775 -- Mark entity as address taken, and kill current values
777 Set_Address_Taken (Ent);
778 Kill_Current_Values (Ent);
781 elsif Nkind_In (PP, N_Selected_Component,
792 -- Check for aliased view unless unrestricted case. We allow a
793 -- nonaliased prefix when within an instance because the prefix may
794 -- have been a tagged formal object, which is defined to be aliased
795 -- even when the actual might not be (other instance cases will have
796 -- been caught in the generic). Similarly, within an inlined body we
797 -- know that the attribute is legal in the original subprogram, and
798 -- therefore legal in the expansion.
800 if Aname /= Name_Unrestricted_Access
801 and then not Is_Aliased_View (P)
802 and then not In_Instance
803 and then not In_Inlined_Body
805 Error_Attr_P ("prefix of % attribute must be aliased");
807 end Analyze_Access_Attribute;
809 --------------------------------
810 -- Check_Array_Or_Scalar_Type --
811 --------------------------------
813 procedure Check_Array_Or_Scalar_Type is
817 -- Dimension number for array attributes
820 -- Case of string literal or string literal subtype. These cases
821 -- cannot arise from legal Ada code, but the expander is allowed
822 -- to generate them. They require special handling because string
823 -- literal subtypes do not have standard bounds (the whole idea
824 -- of these subtypes is to avoid having to generate the bounds)
826 if Ekind (P_Type) = E_String_Literal_Subtype then
827 Set_Etype (N, Etype (First_Index (P_Base_Type)));
832 elsif Is_Scalar_Type (P_Type) then
836 Error_Attr ("invalid argument in % attribute", E1);
838 Set_Etype (N, P_Base_Type);
842 -- The following is a special test to allow 'First to apply to
843 -- private scalar types if the attribute comes from generated
844 -- code. This occurs in the case of Normalize_Scalars code.
846 elsif Is_Private_Type (P_Type)
847 and then Present (Full_View (P_Type))
848 and then Is_Scalar_Type (Full_View (P_Type))
849 and then not Comes_From_Source (N)
851 Set_Etype (N, Implementation_Base_Type (P_Type));
853 -- Array types other than string literal subtypes handled above
858 -- We know prefix is an array type, or the name of an array
859 -- object, and that the expression, if present, is static
860 -- and within the range of the dimensions of the type.
862 pragma Assert (Is_Array_Type (P_Type));
863 Index := First_Index (P_Base_Type);
867 -- First dimension assumed
869 Set_Etype (N, Base_Type (Etype (Index)));
872 D := UI_To_Int (Intval (E1));
874 for J in 1 .. D - 1 loop
878 Set_Etype (N, Base_Type (Etype (Index)));
879 Set_Etype (E1, Standard_Integer);
882 end Check_Array_Or_Scalar_Type;
884 ----------------------
885 -- Check_Array_Type --
886 ----------------------
888 procedure Check_Array_Type is
890 -- Dimension number for array attributes
893 -- If the type is a string literal type, then this must be generated
894 -- internally, and no further check is required on its legality.
896 if Ekind (P_Type) = E_String_Literal_Subtype then
899 -- If the type is a composite, it is an illegal aggregate, no point
902 elsif P_Type = Any_Composite then
906 -- Normal case of array type or subtype
908 Check_Either_E0_Or_E1;
911 if Is_Array_Type (P_Type) then
912 if not Is_Constrained (P_Type)
913 and then Is_Entity_Name (P)
914 and then Is_Type (Entity (P))
916 -- Note: we do not call Error_Attr here, since we prefer to
917 -- continue, using the relevant index type of the array,
918 -- even though it is unconstrained. This gives better error
919 -- recovery behavior.
921 Error_Msg_Name_1 := Aname;
923 ("prefix for % attribute must be constrained array", P);
926 D := Number_Dimensions (P_Type);
929 if Is_Private_Type (P_Type) then
930 Error_Attr_P ("prefix for % attribute may not be private type");
932 elsif Is_Access_Type (P_Type)
933 and then Is_Array_Type (Designated_Type (P_Type))
934 and then Is_Entity_Name (P)
935 and then Is_Type (Entity (P))
937 Error_Attr_P ("prefix of % attribute cannot be access type");
939 elsif Attr_Id = Attribute_First
941 Attr_Id = Attribute_Last
943 Error_Attr ("invalid prefix for % attribute", P);
946 Error_Attr_P ("prefix for % attribute must be array");
951 Resolve (E1, Any_Integer);
952 Set_Etype (E1, Standard_Integer);
954 if not Is_Static_Expression (E1)
955 or else Raises_Constraint_Error (E1)
958 ("expression for dimension must be static!", E1);
961 elsif UI_To_Int (Expr_Value (E1)) > D
962 or else UI_To_Int (Expr_Value (E1)) < 1
964 Error_Attr ("invalid dimension number for array type", E1);
968 if (Style_Check and Style_Check_Array_Attribute_Index)
969 and then Comes_From_Source (N)
971 Style.Check_Array_Attribute_Index (N, E1, D);
973 end Check_Array_Type;
975 -------------------------
976 -- Check_Asm_Attribute --
977 -------------------------
979 procedure Check_Asm_Attribute is
984 -- Check first argument is static string expression
986 Analyze_And_Resolve (E1, Standard_String);
988 if Etype (E1) = Any_Type then
991 elsif not Is_OK_Static_Expression (E1) then
993 ("constraint argument must be static string expression!", E1);
997 -- Check second argument is right type
999 Analyze_And_Resolve (E2, Entity (P));
1001 -- Note: that is all we need to do, we don't need to check
1002 -- that it appears in a correct context. The Ada type system
1003 -- will do that for us.
1005 end Check_Asm_Attribute;
1007 ---------------------
1008 -- Check_Component --
1009 ---------------------
1011 procedure Check_Component is
1015 if Nkind (P) /= N_Selected_Component
1017 (Ekind (Entity (Selector_Name (P))) /= E_Component
1019 Ekind (Entity (Selector_Name (P))) /= E_Discriminant)
1021 Error_Attr_P ("prefix for % attribute must be selected component");
1023 end Check_Component;
1025 ------------------------------------
1026 -- Check_Decimal_Fixed_Point_Type --
1027 ------------------------------------
1029 procedure Check_Decimal_Fixed_Point_Type is
1033 if not Is_Decimal_Fixed_Point_Type (P_Type) then
1034 Error_Attr_P ("prefix of % attribute must be decimal type");
1036 end Check_Decimal_Fixed_Point_Type;
1038 -----------------------
1039 -- Check_Dereference --
1040 -----------------------
1042 procedure Check_Dereference is
1045 -- Case of a subtype mark
1047 if Is_Entity_Name (P)
1048 and then Is_Type (Entity (P))
1053 -- Case of an expression
1057 if Is_Access_Type (P_Type) then
1059 -- If there is an implicit dereference, then we must freeze
1060 -- the designated type of the access type, since the type of
1061 -- the referenced array is this type (see AI95-00106).
1063 Freeze_Before (N, Designated_Type (P_Type));
1066 Make_Explicit_Dereference (Sloc (P),
1067 Prefix => Relocate_Node (P)));
1069 Analyze_And_Resolve (P);
1070 P_Type := Etype (P);
1072 if P_Type = Any_Type then
1073 raise Bad_Attribute;
1076 P_Base_Type := Base_Type (P_Type);
1078 end Check_Dereference;
1080 -------------------------
1081 -- Check_Discrete_Type --
1082 -------------------------
1084 procedure Check_Discrete_Type is
1088 if not Is_Discrete_Type (P_Type) then
1089 Error_Attr_P ("prefix of % attribute must be discrete type");
1091 end Check_Discrete_Type;
1097 procedure Check_E0 is
1099 if Present (E1) then
1100 Unexpected_Argument (E1);
1108 procedure Check_E1 is
1110 Check_Either_E0_Or_E1;
1114 -- Special-case attributes that are functions and that appear as
1115 -- the prefix of another attribute. Error is posted on parent.
1117 if Nkind (Parent (N)) = N_Attribute_Reference
1118 and then (Attribute_Name (Parent (N)) = Name_Address
1120 Attribute_Name (Parent (N)) = Name_Code_Address
1122 Attribute_Name (Parent (N)) = Name_Access)
1124 Error_Msg_Name_1 := Attribute_Name (Parent (N));
1125 Error_Msg_N ("illegal prefix for % attribute", Parent (N));
1126 Set_Etype (Parent (N), Any_Type);
1127 Set_Entity (Parent (N), Any_Type);
1128 raise Bad_Attribute;
1131 Error_Attr ("missing argument for % attribute", N);
1140 procedure Check_E2 is
1143 Error_Attr ("missing arguments for % attribute (2 required)", N);
1145 Error_Attr ("missing argument for % attribute (2 required)", N);
1149 ---------------------------
1150 -- Check_Either_E0_Or_E1 --
1151 ---------------------------
1153 procedure Check_Either_E0_Or_E1 is
1155 if Present (E2) then
1156 Unexpected_Argument (E2);
1158 end Check_Either_E0_Or_E1;
1160 ----------------------
1161 -- Check_Enum_Image --
1162 ----------------------
1164 procedure Check_Enum_Image is
1167 if Is_Enumeration_Type (P_Base_Type) then
1168 Lit := First_Literal (P_Base_Type);
1169 while Present (Lit) loop
1170 Set_Referenced (Lit);
1174 end Check_Enum_Image;
1176 ----------------------------
1177 -- Check_Fixed_Point_Type --
1178 ----------------------------
1180 procedure Check_Fixed_Point_Type is
1184 if not Is_Fixed_Point_Type (P_Type) then
1185 Error_Attr_P ("prefix of % attribute must be fixed point type");
1187 end Check_Fixed_Point_Type;
1189 ------------------------------
1190 -- Check_Fixed_Point_Type_0 --
1191 ------------------------------
1193 procedure Check_Fixed_Point_Type_0 is
1195 Check_Fixed_Point_Type;
1197 end Check_Fixed_Point_Type_0;
1199 -------------------------------
1200 -- Check_Floating_Point_Type --
1201 -------------------------------
1203 procedure Check_Floating_Point_Type is
1207 if not Is_Floating_Point_Type (P_Type) then
1208 Error_Attr_P ("prefix of % attribute must be float type");
1210 end Check_Floating_Point_Type;
1212 ---------------------------------
1213 -- Check_Floating_Point_Type_0 --
1214 ---------------------------------
1216 procedure Check_Floating_Point_Type_0 is
1218 Check_Floating_Point_Type;
1220 end Check_Floating_Point_Type_0;
1222 ---------------------------------
1223 -- Check_Floating_Point_Type_1 --
1224 ---------------------------------
1226 procedure Check_Floating_Point_Type_1 is
1228 Check_Floating_Point_Type;
1230 end Check_Floating_Point_Type_1;
1232 ---------------------------------
1233 -- Check_Floating_Point_Type_2 --
1234 ---------------------------------
1236 procedure Check_Floating_Point_Type_2 is
1238 Check_Floating_Point_Type;
1240 end Check_Floating_Point_Type_2;
1242 ------------------------
1243 -- Check_Integer_Type --
1244 ------------------------
1246 procedure Check_Integer_Type is
1250 if not Is_Integer_Type (P_Type) then
1251 Error_Attr_P ("prefix of % attribute must be integer type");
1253 end Check_Integer_Type;
1255 ------------------------
1256 -- Check_Library_Unit --
1257 ------------------------
1259 procedure Check_Library_Unit is
1261 if not Is_Compilation_Unit (Entity (P)) then
1262 Error_Attr_P ("prefix of % attribute must be library unit");
1264 end Check_Library_Unit;
1266 --------------------------------
1267 -- Check_Modular_Integer_Type --
1268 --------------------------------
1270 procedure Check_Modular_Integer_Type is
1274 if not Is_Modular_Integer_Type (P_Type) then
1276 ("prefix of % attribute must be modular integer type");
1278 end Check_Modular_Integer_Type;
1280 ------------------------
1281 -- Check_Not_CPP_Type --
1282 ------------------------
1284 procedure Check_Not_CPP_Type is
1286 if Is_Tagged_Type (Etype (P))
1287 and then Convention (Etype (P)) = Convention_CPP
1288 and then Is_CPP_Class (Root_Type (Etype (P)))
1291 ("invalid use of % attribute with 'C'P'P tagged type");
1293 end Check_Not_CPP_Type;
1295 -------------------------------
1296 -- Check_Not_Incomplete_Type --
1297 -------------------------------
1299 procedure Check_Not_Incomplete_Type is
1304 -- Ada 2005 (AI-50217, AI-326): If the prefix is an explicit
1305 -- dereference we have to check wrong uses of incomplete types
1306 -- (other wrong uses are checked at their freezing point).
1308 -- Example 1: Limited-with
1310 -- limited with Pkg;
1312 -- type Acc is access Pkg.T;
1314 -- S : Integer := X.all'Size; -- ERROR
1317 -- Example 2: Tagged incomplete
1319 -- type T is tagged;
1320 -- type Acc is access all T;
1322 -- S : constant Integer := X.all'Size; -- ERROR
1323 -- procedure Q (Obj : Integer := X.all'Alignment); -- ERROR
1325 if Ada_Version >= Ada_05
1326 and then Nkind (P) = N_Explicit_Dereference
1329 while Nkind (E) = N_Explicit_Dereference loop
1333 if From_With_Type (Etype (E)) then
1335 ("prefix of % attribute cannot be an incomplete type");
1338 if Is_Access_Type (Etype (E)) then
1339 Typ := Directly_Designated_Type (Etype (E));
1344 if Ekind (Typ) = E_Incomplete_Type
1345 and then No (Full_View (Typ))
1348 ("prefix of % attribute cannot be an incomplete type");
1353 if not Is_Entity_Name (P)
1354 or else not Is_Type (Entity (P))
1355 or else In_Spec_Expression
1359 Check_Fully_Declared (P_Type, P);
1361 end Check_Not_Incomplete_Type;
1363 ----------------------------
1364 -- Check_Object_Reference --
1365 ----------------------------
1367 procedure Check_Object_Reference (P : Node_Id) is
1371 -- If we need an object, and we have a prefix that is the name of
1372 -- a function entity, convert it into a function call.
1374 if Is_Entity_Name (P)
1375 and then Ekind (Entity (P)) = E_Function
1377 Rtyp := Etype (Entity (P));
1380 Make_Function_Call (Sloc (P),
1381 Name => Relocate_Node (P)));
1383 Analyze_And_Resolve (P, Rtyp);
1385 -- Otherwise we must have an object reference
1387 elsif not Is_Object_Reference (P) then
1388 Error_Attr_P ("prefix of % attribute must be object");
1390 end Check_Object_Reference;
1392 ----------------------------
1393 -- Check_PolyORB_Attribute --
1394 ----------------------------
1396 procedure Check_PolyORB_Attribute is
1398 Validate_Non_Static_Attribute_Function_Call;
1403 if Get_PCS_Name /= Name_PolyORB_DSA then
1405 ("attribute% requires the 'Poly'O'R'B 'P'C'S", N);
1407 end Check_PolyORB_Attribute;
1409 ------------------------
1410 -- Check_Program_Unit --
1411 ------------------------
1413 procedure Check_Program_Unit is
1415 if Is_Entity_Name (P) then
1417 K : constant Entity_Kind := Ekind (Entity (P));
1418 T : constant Entity_Id := Etype (Entity (P));
1421 if K in Subprogram_Kind
1422 or else K in Task_Kind
1423 or else K in Protected_Kind
1424 or else K = E_Package
1425 or else K in Generic_Unit_Kind
1426 or else (K = E_Variable
1430 Is_Protected_Type (T)))
1437 Error_Attr_P ("prefix of % attribute must be program unit");
1438 end Check_Program_Unit;
1440 ---------------------
1441 -- Check_Real_Type --
1442 ---------------------
1444 procedure Check_Real_Type is
1448 if not Is_Real_Type (P_Type) then
1449 Error_Attr_P ("prefix of % attribute must be real type");
1451 end Check_Real_Type;
1453 -----------------------
1454 -- Check_Scalar_Type --
1455 -----------------------
1457 procedure Check_Scalar_Type is
1461 if not Is_Scalar_Type (P_Type) then
1462 Error_Attr_P ("prefix of % attribute must be scalar type");
1464 end Check_Scalar_Type;
1466 ---------------------------
1467 -- Check_Standard_Prefix --
1468 ---------------------------
1470 procedure Check_Standard_Prefix is
1474 if Nkind (P) /= N_Identifier
1475 or else Chars (P) /= Name_Standard
1477 Error_Attr ("only allowed prefix for % attribute is Standard", P);
1479 end Check_Standard_Prefix;
1481 ----------------------------
1482 -- Check_Stream_Attribute --
1483 ----------------------------
1485 procedure Check_Stream_Attribute (Nam : TSS_Name_Type) is
1489 In_Shared_Var_Procs : Boolean;
1490 -- True when compiling the body of System.Shared_Storage.
1491 -- Shared_Var_Procs. For this runtime package (always compiled in
1492 -- GNAT mode), we allow stream attributes references for limited
1493 -- types for the case where shared passive objects are implemented
1494 -- using stream attributes, which is the default in GNAT's persistent
1495 -- storage implementation.
1498 Validate_Non_Static_Attribute_Function_Call;
1500 -- With the exception of 'Input, Stream attributes are procedures,
1501 -- and can only appear at the position of procedure calls. We check
1502 -- for this here, before they are rewritten, to give a more precise
1505 if Nam = TSS_Stream_Input then
1508 elsif Is_List_Member (N)
1509 and then not Nkind_In (Parent (N), N_Procedure_Call_Statement,
1516 ("invalid context for attribute%, which is a procedure", N);
1520 Btyp := Implementation_Base_Type (P_Type);
1522 -- Stream attributes not allowed on limited types unless the
1523 -- attribute reference was generated by the expander (in which
1524 -- case the underlying type will be used, as described in Sinfo),
1525 -- or the attribute was specified explicitly for the type itself
1526 -- or one of its ancestors (taking visibility rules into account if
1527 -- in Ada 2005 mode), or a pragma Stream_Convert applies to Btyp
1528 -- (with no visibility restriction).
1531 Gen_Body : constant Node_Id := Enclosing_Generic_Body (N);
1533 if Present (Gen_Body) then
1534 In_Shared_Var_Procs :=
1535 Is_RTE (Corresponding_Spec (Gen_Body), RE_Shared_Var_Procs);
1537 In_Shared_Var_Procs := False;
1541 if (Comes_From_Source (N)
1542 and then not (In_Shared_Var_Procs or In_Instance))
1543 and then not Stream_Attribute_Available (P_Type, Nam)
1544 and then not Has_Rep_Pragma (Btyp, Name_Stream_Convert)
1546 Error_Msg_Name_1 := Aname;
1548 if Is_Limited_Type (P_Type) then
1550 ("limited type& has no% attribute", P, P_Type);
1551 Explain_Limited_Type (P_Type, P);
1554 ("attribute% for type& is not available", P, P_Type);
1558 -- Check restriction violations
1560 Check_Restriction (No_Streams, P);
1562 if Is_RTE (P_Type, RE_Exception_Id)
1564 Is_RTE (P_Type, RE_Exception_Occurrence)
1566 Check_Restriction (No_Exception_Registration, P);
1569 -- Here we must check that the first argument is an access type
1570 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
1572 Analyze_And_Resolve (E1);
1575 -- Note: the double call to Root_Type here is needed because the
1576 -- root type of a class-wide type is the corresponding type (e.g.
1577 -- X for X'Class, and we really want to go to the root.)
1579 if not Is_Access_Type (Etyp)
1580 or else Root_Type (Root_Type (Designated_Type (Etyp))) /=
1581 RTE (RE_Root_Stream_Type)
1584 ("expected access to Ada.Streams.Root_Stream_Type''Class", E1);
1587 -- Check that the second argument is of the right type if there is
1588 -- one (the Input attribute has only one argument so this is skipped)
1590 if Present (E2) then
1593 if Nam = TSS_Stream_Read
1594 and then not Is_OK_Variable_For_Out_Formal (E2)
1597 ("second argument of % attribute must be a variable", E2);
1600 Resolve (E2, P_Type);
1604 end Check_Stream_Attribute;
1606 -----------------------
1607 -- Check_Task_Prefix --
1608 -----------------------
1610 procedure Check_Task_Prefix is
1614 -- Ada 2005 (AI-345): Attribute 'Terminated can be applied to
1615 -- task interface class-wide types.
1617 if Is_Task_Type (Etype (P))
1618 or else (Is_Access_Type (Etype (P))
1619 and then Is_Task_Type (Designated_Type (Etype (P))))
1620 or else (Ada_Version >= Ada_05
1621 and then Ekind (Etype (P)) = E_Class_Wide_Type
1622 and then Is_Interface (Etype (P))
1623 and then Is_Task_Interface (Etype (P)))
1628 if Ada_Version >= Ada_05 then
1630 ("prefix of % attribute must be a task or a task " &
1631 "interface class-wide object");
1634 Error_Attr_P ("prefix of % attribute must be a task");
1637 end Check_Task_Prefix;
1643 -- The possibilities are an entity name denoting a type, or an
1644 -- attribute reference that denotes a type (Base or Class). If
1645 -- the type is incomplete, replace it with its full view.
1647 procedure Check_Type is
1649 if not Is_Entity_Name (P)
1650 or else not Is_Type (Entity (P))
1652 Error_Attr_P ("prefix of % attribute must be a type");
1654 elsif Is_Protected_Self_Reference (P) then
1656 ("prefix of % attribute denotes current instance "
1657 & "(RM 9.4(21/2))");
1659 elsif Ekind (Entity (P)) = E_Incomplete_Type
1660 and then Present (Full_View (Entity (P)))
1662 P_Type := Full_View (Entity (P));
1663 Set_Entity (P, P_Type);
1667 ---------------------
1668 -- Check_Unit_Name --
1669 ---------------------
1671 procedure Check_Unit_Name (Nod : Node_Id) is
1673 if Nkind (Nod) = N_Identifier then
1676 elsif Nkind (Nod) = N_Selected_Component then
1677 Check_Unit_Name (Prefix (Nod));
1679 if Nkind (Selector_Name (Nod)) = N_Identifier then
1684 Error_Attr ("argument for % attribute must be unit name", P);
1685 end Check_Unit_Name;
1691 procedure Error_Attr is
1693 Set_Etype (N, Any_Type);
1694 Set_Entity (N, Any_Type);
1695 raise Bad_Attribute;
1698 procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
1700 Error_Msg_Name_1 := Aname;
1701 Error_Msg_N (Msg, Error_Node);
1709 procedure Error_Attr_P (Msg : String) is
1711 Error_Msg_Name_1 := Aname;
1712 Error_Msg_F (Msg, P);
1716 ----------------------------
1717 -- Legal_Formal_Attribute --
1718 ----------------------------
1720 procedure Legal_Formal_Attribute is
1724 if not Is_Entity_Name (P)
1725 or else not Is_Type (Entity (P))
1727 Error_Attr_P ("prefix of % attribute must be generic type");
1729 elsif Is_Generic_Actual_Type (Entity (P))
1731 or else In_Inlined_Body
1735 elsif Is_Generic_Type (Entity (P)) then
1736 if not Is_Indefinite_Subtype (Entity (P)) then
1738 ("prefix of % attribute must be indefinite generic type");
1743 ("prefix of % attribute must be indefinite generic type");
1746 Set_Etype (N, Standard_Boolean);
1747 end Legal_Formal_Attribute;
1749 ------------------------
1750 -- Standard_Attribute --
1751 ------------------------
1753 procedure Standard_Attribute (Val : Int) is
1755 Check_Standard_Prefix;
1756 Rewrite (N, Make_Integer_Literal (Loc, Val));
1758 end Standard_Attribute;
1760 -------------------------
1761 -- Unexpected Argument --
1762 -------------------------
1764 procedure Unexpected_Argument (En : Node_Id) is
1766 Error_Attr ("unexpected argument for % attribute", En);
1767 end Unexpected_Argument;
1769 -------------------------------------------------
1770 -- Validate_Non_Static_Attribute_Function_Call --
1771 -------------------------------------------------
1773 -- This function should be moved to Sem_Dist ???
1775 procedure Validate_Non_Static_Attribute_Function_Call is
1777 if In_Preelaborated_Unit
1778 and then not In_Subprogram_Or_Concurrent_Unit
1780 Flag_Non_Static_Expr
1781 ("non-static function call in preelaborated unit!", N);
1783 end Validate_Non_Static_Attribute_Function_Call;
1785 -----------------------------------------------
1786 -- Start of Processing for Analyze_Attribute --
1787 -----------------------------------------------
1790 -- Immediate return if unrecognized attribute (already diagnosed
1791 -- by parser, so there is nothing more that we need to do)
1793 if not Is_Attribute_Name (Aname) then
1794 raise Bad_Attribute;
1797 -- Deal with Ada 83 issues
1799 if Comes_From_Source (N) then
1800 if not Attribute_83 (Attr_Id) then
1801 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
1802 Error_Msg_Name_1 := Aname;
1803 Error_Msg_N ("(Ada 83) attribute% is not standard?", N);
1806 if Attribute_Impl_Def (Attr_Id) then
1807 Check_Restriction (No_Implementation_Attributes, N);
1812 -- Deal with Ada 2005 issues
1814 if Attribute_05 (Attr_Id) and then Ada_Version <= Ada_95 then
1815 Check_Restriction (No_Implementation_Attributes, N);
1818 -- Remote access to subprogram type access attribute reference needs
1819 -- unanalyzed copy for tree transformation. The analyzed copy is used
1820 -- for its semantic information (whether prefix is a remote subprogram
1821 -- name), the unanalyzed copy is used to construct new subtree rooted
1822 -- with N_Aggregate which represents a fat pointer aggregate.
1824 if Aname = Name_Access then
1825 Discard_Node (Copy_Separate_Tree (N));
1828 -- Analyze prefix and exit if error in analysis. If the prefix is an
1829 -- incomplete type, use full view if available. Note that there are
1830 -- some attributes for which we do not analyze the prefix, since the
1831 -- prefix is not a normal name.
1833 if Aname /= Name_Elab_Body
1835 Aname /= Name_Elab_Spec
1837 Aname /= Name_UET_Address
1839 Aname /= Name_Enabled
1842 P_Type := Etype (P);
1844 if Is_Entity_Name (P)
1845 and then Present (Entity (P))
1846 and then Is_Type (Entity (P))
1848 if Ekind (Entity (P)) = E_Incomplete_Type then
1849 P_Type := Get_Full_View (P_Type);
1850 Set_Entity (P, P_Type);
1851 Set_Etype (P, P_Type);
1853 elsif Entity (P) = Current_Scope
1854 and then Is_Record_Type (Entity (P))
1856 -- Use of current instance within the type. Verify that if the
1857 -- attribute appears within a constraint, it yields an access
1858 -- type, other uses are illegal.
1866 and then Nkind (Parent (Par)) /= N_Component_Definition
1868 Par := Parent (Par);
1872 and then Nkind (Par) = N_Subtype_Indication
1874 if Attr_Id /= Attribute_Access
1875 and then Attr_Id /= Attribute_Unchecked_Access
1876 and then Attr_Id /= Attribute_Unrestricted_Access
1879 ("in a constraint the current instance can only"
1880 & " be used with an access attribute", N);
1887 if P_Type = Any_Type then
1888 raise Bad_Attribute;
1891 P_Base_Type := Base_Type (P_Type);
1894 -- Analyze expressions that may be present, exiting if an error occurs
1901 E1 := First (Exprs);
1904 -- Check for missing/bad expression (result of previous error)
1906 if No (E1) or else Etype (E1) = Any_Type then
1907 raise Bad_Attribute;
1912 if Present (E2) then
1915 if Etype (E2) = Any_Type then
1916 raise Bad_Attribute;
1919 if Present (Next (E2)) then
1920 Unexpected_Argument (Next (E2));
1925 -- Ada 2005 (AI-345): Ensure that the compiler gives exactly the current
1926 -- output compiling in Ada 95 mode for the case of ambiguous prefixes.
1928 if Ada_Version < Ada_05
1929 and then Is_Overloaded (P)
1930 and then Aname /= Name_Access
1931 and then Aname /= Name_Address
1932 and then Aname /= Name_Code_Address
1933 and then Aname /= Name_Count
1934 and then Aname /= Name_Result
1935 and then Aname /= Name_Unchecked_Access
1937 Error_Attr ("ambiguous prefix for % attribute", P);
1939 elsif Ada_Version >= Ada_05
1940 and then Is_Overloaded (P)
1941 and then Aname /= Name_Access
1942 and then Aname /= Name_Address
1943 and then Aname /= Name_Code_Address
1944 and then Aname /= Name_Result
1945 and then Aname /= Name_Unchecked_Access
1947 -- Ada 2005 (AI-345): Since protected and task types have primitive
1948 -- entry wrappers, the attributes Count, Caller and AST_Entry require
1951 if Aname = Name_Count
1952 or else Aname = Name_Caller
1953 or else Aname = Name_AST_Entry
1956 Count : Natural := 0;
1961 Get_First_Interp (P, I, It);
1962 while Present (It.Nam) loop
1963 if Comes_From_Source (It.Nam) then
1969 Get_Next_Interp (I, It);
1973 Error_Attr ("ambiguous prefix for % attribute", P);
1975 Set_Is_Overloaded (P, False);
1980 Error_Attr ("ambiguous prefix for % attribute", P);
1984 -- Remaining processing depends on attribute
1992 when Attribute_Abort_Signal =>
1993 Check_Standard_Prefix;
1995 New_Reference_To (Stand.Abort_Signal, Loc));
2002 when Attribute_Access =>
2003 Analyze_Access_Attribute;
2009 when Attribute_Address =>
2012 -- Check for some junk cases, where we have to allow the address
2013 -- attribute but it does not make much sense, so at least for now
2014 -- just replace with Null_Address.
2016 -- We also do this if the prefix is a reference to the AST_Entry
2017 -- attribute. If expansion is active, the attribute will be
2018 -- replaced by a function call, and address will work fine and
2019 -- get the proper value, but if expansion is not active, then
2020 -- the check here allows proper semantic analysis of the reference.
2022 -- An Address attribute created by expansion is legal even when it
2023 -- applies to other entity-denoting expressions.
2025 if Is_Protected_Self_Reference (P) then
2027 -- Address attribute on a protected object self reference is legal
2031 elsif Is_Entity_Name (P) then
2033 Ent : constant Entity_Id := Entity (P);
2036 if Is_Subprogram (Ent) then
2037 Set_Address_Taken (Ent);
2038 Kill_Current_Values (Ent);
2040 -- An Address attribute is accepted when generated by the
2041 -- compiler for dispatching operation, and an error is
2042 -- issued once the subprogram is frozen (to avoid confusing
2043 -- errors about implicit uses of Address in the dispatch
2044 -- table initialization).
2046 if Has_Pragma_Inline_Always (Entity (P))
2047 and then Comes_From_Source (P)
2050 ("prefix of % attribute cannot be Inline_Always" &
2053 -- It is illegal to apply 'Address to an intrinsic
2054 -- subprogram. This is now formalized in AI05-0095.
2055 -- In an instance, an attempt to obtain 'Address of an
2056 -- intrinsic subprogram (e.g the renaming of a predefined
2057 -- operator that is an actual) raises Program_Error.
2059 elsif Convention (Ent) = Convention_Intrinsic then
2062 Make_Raise_Program_Error (Loc,
2063 Reason => PE_Address_Of_Intrinsic));
2066 ("cannot take Address of intrinsic subprogram", N);
2070 elsif Is_Object (Ent)
2071 or else Ekind (Ent) = E_Label
2073 Set_Address_Taken (Ent);
2075 -- If we have an address of an object, and the attribute
2076 -- comes from source, then set the object as potentially
2077 -- source modified. We do this because the resulting address
2078 -- can potentially be used to modify the variable and we
2079 -- might not detect this, leading to some junk warnings.
2081 Set_Never_Set_In_Source (Ent, False);
2083 elsif (Is_Concurrent_Type (Etype (Ent))
2084 and then Etype (Ent) = Base_Type (Ent))
2085 or else Ekind (Ent) = E_Package
2086 or else Is_Generic_Unit (Ent)
2089 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2092 Error_Attr ("invalid prefix for % attribute", P);
2096 elsif Nkind (P) = N_Attribute_Reference
2097 and then Attribute_Name (P) = Name_AST_Entry
2100 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
2102 elsif Is_Object_Reference (P) then
2105 elsif Nkind (P) = N_Selected_Component
2106 and then Is_Subprogram (Entity (Selector_Name (P)))
2110 -- What exactly are we allowing here ??? and is this properly
2111 -- documented in the sinfo documentation for this node ???
2113 elsif not Comes_From_Source (N) then
2117 Error_Attr ("invalid prefix for % attribute", P);
2120 Set_Etype (N, RTE (RE_Address));
2126 when Attribute_Address_Size =>
2127 Standard_Attribute (System_Address_Size);
2133 when Attribute_Adjacent =>
2134 Check_Floating_Point_Type_2;
2135 Set_Etype (N, P_Base_Type);
2136 Resolve (E1, P_Base_Type);
2137 Resolve (E2, P_Base_Type);
2143 when Attribute_Aft =>
2144 Check_Fixed_Point_Type_0;
2145 Set_Etype (N, Universal_Integer);
2151 when Attribute_Alignment =>
2153 -- Don't we need more checking here, cf Size ???
2156 Check_Not_Incomplete_Type;
2158 Set_Etype (N, Universal_Integer);
2164 when Attribute_Asm_Input =>
2165 Check_Asm_Attribute;
2166 Set_Etype (N, RTE (RE_Asm_Input_Operand));
2172 when Attribute_Asm_Output =>
2173 Check_Asm_Attribute;
2175 if Etype (E2) = Any_Type then
2178 elsif Aname = Name_Asm_Output then
2179 if not Is_Variable (E2) then
2181 ("second argument for Asm_Output is not variable", E2);
2185 Note_Possible_Modification (E2, Sure => True);
2186 Set_Etype (N, RTE (RE_Asm_Output_Operand));
2192 when Attribute_AST_Entry => AST_Entry : declare
2198 -- Indicates if entry family index is present. Note the coding
2199 -- here handles the entry family case, but in fact it cannot be
2200 -- executed currently, because pragma AST_Entry does not permit
2201 -- the specification of an entry family.
2203 procedure Bad_AST_Entry;
2204 -- Signal a bad AST_Entry pragma
2206 function OK_Entry (E : Entity_Id) return Boolean;
2207 -- Checks that E is of an appropriate entity kind for an entry
2208 -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index
2209 -- is set True for the entry family case). In the True case,
2210 -- makes sure that Is_AST_Entry is set on the entry.
2216 procedure Bad_AST_Entry is
2218 Error_Attr_P ("prefix for % attribute must be task entry");
2225 function OK_Entry (E : Entity_Id) return Boolean is
2230 Result := (Ekind (E) = E_Entry_Family);
2232 Result := (Ekind (E) = E_Entry);
2236 if not Is_AST_Entry (E) then
2237 Error_Msg_Name_2 := Aname;
2238 Error_Attr ("% attribute requires previous % pragma", P);
2245 -- Start of processing for AST_Entry
2251 -- Deal with entry family case
2253 if Nkind (P) = N_Indexed_Component then
2261 Ptyp := Etype (Pref);
2263 if Ptyp = Any_Type or else Error_Posted (Pref) then
2267 -- If the prefix is a selected component whose prefix is of an
2268 -- access type, then introduce an explicit dereference.
2269 -- ??? Could we reuse Check_Dereference here?
2271 if Nkind (Pref) = N_Selected_Component
2272 and then Is_Access_Type (Ptyp)
2275 Make_Explicit_Dereference (Sloc (Pref),
2276 Relocate_Node (Pref)));
2277 Analyze_And_Resolve (Pref, Designated_Type (Ptyp));
2280 -- Prefix can be of the form a.b, where a is a task object
2281 -- and b is one of the entries of the corresponding task type.
2283 if Nkind (Pref) = N_Selected_Component
2284 and then OK_Entry (Entity (Selector_Name (Pref)))
2285 and then Is_Object_Reference (Prefix (Pref))
2286 and then Is_Task_Type (Etype (Prefix (Pref)))
2290 -- Otherwise the prefix must be an entry of a containing task,
2291 -- or of a variable of the enclosing task type.
2294 if Nkind_In (Pref, N_Identifier, N_Expanded_Name) then
2295 Ent := Entity (Pref);
2297 if not OK_Entry (Ent)
2298 or else not In_Open_Scopes (Scope (Ent))
2308 Set_Etype (N, RTE (RE_AST_Handler));
2315 -- Note: when the base attribute appears in the context of a subtype
2316 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
2317 -- the following circuit.
2319 when Attribute_Base => Base : declare
2327 if Ada_Version >= Ada_95
2328 and then not Is_Scalar_Type (Typ)
2329 and then not Is_Generic_Type (Typ)
2331 Error_Attr_P ("prefix of Base attribute must be scalar type");
2333 elsif Sloc (Typ) = Standard_Location
2334 and then Base_Type (Typ) = Typ
2335 and then Warn_On_Redundant_Constructs
2338 ("?redundant attribute, & is its own base type", N, Typ);
2341 Set_Etype (N, Base_Type (Entity (P)));
2342 Set_Entity (N, Base_Type (Entity (P)));
2343 Rewrite (N, New_Reference_To (Entity (N), Loc));
2351 when Attribute_Bit => Bit :
2355 if not Is_Object_Reference (P) then
2356 Error_Attr_P ("prefix for % attribute must be object");
2358 -- What about the access object cases ???
2364 Set_Etype (N, Universal_Integer);
2371 when Attribute_Bit_Order => Bit_Order :
2376 if not Is_Record_Type (P_Type) then
2377 Error_Attr_P ("prefix of % attribute must be record type");
2380 if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then
2382 New_Occurrence_Of (RTE (RE_High_Order_First), Loc));
2385 New_Occurrence_Of (RTE (RE_Low_Order_First), Loc));
2388 Set_Etype (N, RTE (RE_Bit_Order));
2391 -- Reset incorrect indication of staticness
2393 Set_Is_Static_Expression (N, False);
2400 -- Note: in generated code, we can have a Bit_Position attribute
2401 -- applied to a (naked) record component (i.e. the prefix is an
2402 -- identifier that references an E_Component or E_Discriminant
2403 -- entity directly, and this is interpreted as expected by Gigi.
2404 -- The following code will not tolerate such usage, but when the
2405 -- expander creates this special case, it marks it as analyzed
2406 -- immediately and sets an appropriate type.
2408 when Attribute_Bit_Position =>
2409 if Comes_From_Source (N) then
2413 Set_Etype (N, Universal_Integer);
2419 when Attribute_Body_Version =>
2422 Set_Etype (N, RTE (RE_Version_String));
2428 when Attribute_Callable =>
2430 Set_Etype (N, Standard_Boolean);
2437 when Attribute_Caller => Caller : declare
2444 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2447 if not Is_Entry (Ent) then
2448 Error_Attr ("invalid entry name", N);
2452 Error_Attr ("invalid entry name", N);
2456 for J in reverse 0 .. Scope_Stack.Last loop
2457 S := Scope_Stack.Table (J).Entity;
2459 if S = Scope (Ent) then
2460 Error_Attr ("Caller must appear in matching accept or body", N);
2466 Set_Etype (N, RTE (RO_AT_Task_Id));
2473 when Attribute_Ceiling =>
2474 Check_Floating_Point_Type_1;
2475 Set_Etype (N, P_Base_Type);
2476 Resolve (E1, P_Base_Type);
2482 when Attribute_Class =>
2483 Check_Restriction (No_Dispatch, N);
2491 when Attribute_Code_Address =>
2494 if Nkind (P) = N_Attribute_Reference
2495 and then (Attribute_Name (P) = Name_Elab_Body
2497 Attribute_Name (P) = Name_Elab_Spec)
2501 elsif not Is_Entity_Name (P)
2502 or else (Ekind (Entity (P)) /= E_Function
2504 Ekind (Entity (P)) /= E_Procedure)
2506 Error_Attr ("invalid prefix for % attribute", P);
2507 Set_Address_Taken (Entity (P));
2510 Set_Etype (N, RTE (RE_Address));
2512 --------------------
2513 -- Component_Size --
2514 --------------------
2516 when Attribute_Component_Size =>
2518 Set_Etype (N, Universal_Integer);
2520 -- Note: unlike other array attributes, unconstrained arrays are OK
2522 if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then
2532 when Attribute_Compose =>
2533 Check_Floating_Point_Type_2;
2534 Set_Etype (N, P_Base_Type);
2535 Resolve (E1, P_Base_Type);
2536 Resolve (E2, Any_Integer);
2542 when Attribute_Constrained =>
2544 Set_Etype (N, Standard_Boolean);
2546 -- Case from RM J.4(2) of constrained applied to private type
2548 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
2549 Check_Restriction (No_Obsolescent_Features, N);
2551 if Warn_On_Obsolescent_Feature then
2553 ("constrained for private type is an " &
2554 "obsolescent feature (RM J.4)?", N);
2557 -- If we are within an instance, the attribute must be legal
2558 -- because it was valid in the generic unit. Ditto if this is
2559 -- an inlining of a function declared in an instance.
2562 or else In_Inlined_Body
2566 -- For sure OK if we have a real private type itself, but must
2567 -- be completed, cannot apply Constrained to incomplete type.
2569 elsif Is_Private_Type (Entity (P)) then
2571 -- Note: this is one of the Annex J features that does not
2572 -- generate a warning from -gnatwj, since in fact it seems
2573 -- very useful, and is used in the GNAT runtime.
2575 Check_Not_Incomplete_Type;
2579 -- Normal (non-obsolescent case) of application to object of
2580 -- a discriminated type.
2583 Check_Object_Reference (P);
2585 -- If N does not come from source, then we allow the
2586 -- the attribute prefix to be of a private type whose
2587 -- full type has discriminants. This occurs in cases
2588 -- involving expanded calls to stream attributes.
2590 if not Comes_From_Source (N) then
2591 P_Type := Underlying_Type (P_Type);
2594 -- Must have discriminants or be an access type designating
2595 -- a type with discriminants. If it is a classwide type is ???
2596 -- has unknown discriminants.
2598 if Has_Discriminants (P_Type)
2599 or else Has_Unknown_Discriminants (P_Type)
2601 (Is_Access_Type (P_Type)
2602 and then Has_Discriminants (Designated_Type (P_Type)))
2606 -- Also allow an object of a generic type if extensions allowed
2607 -- and allow this for any type at all.
2609 elsif (Is_Generic_Type (P_Type)
2610 or else Is_Generic_Actual_Type (P_Type))
2611 and then Extensions_Allowed
2617 -- Fall through if bad prefix
2620 ("prefix of % attribute must be object of discriminated type");
2626 when Attribute_Copy_Sign =>
2627 Check_Floating_Point_Type_2;
2628 Set_Etype (N, P_Base_Type);
2629 Resolve (E1, P_Base_Type);
2630 Resolve (E2, P_Base_Type);
2636 when Attribute_Count => Count :
2645 if Nkind_In (P, N_Identifier, N_Expanded_Name) then
2648 if Ekind (Ent) /= E_Entry then
2649 Error_Attr ("invalid entry name", N);
2652 elsif Nkind (P) = N_Indexed_Component then
2653 if not Is_Entity_Name (Prefix (P))
2654 or else No (Entity (Prefix (P)))
2655 or else Ekind (Entity (Prefix (P))) /= E_Entry_Family
2657 if Nkind (Prefix (P)) = N_Selected_Component
2658 and then Present (Entity (Selector_Name (Prefix (P))))
2659 and then Ekind (Entity (Selector_Name (Prefix (P)))) =
2663 ("attribute % must apply to entry of current task", P);
2666 Error_Attr ("invalid entry family name", P);
2671 Ent := Entity (Prefix (P));
2674 elsif Nkind (P) = N_Selected_Component
2675 and then Present (Entity (Selector_Name (P)))
2676 and then Ekind (Entity (Selector_Name (P))) = E_Entry
2679 ("attribute % must apply to entry of current task", P);
2682 Error_Attr ("invalid entry name", N);
2686 for J in reverse 0 .. Scope_Stack.Last loop
2687 S := Scope_Stack.Table (J).Entity;
2689 if S = Scope (Ent) then
2690 if Nkind (P) = N_Expanded_Name then
2691 Tsk := Entity (Prefix (P));
2693 -- The prefix denotes either the task type, or else a
2694 -- single task whose task type is being analyzed.
2699 or else (not Is_Type (Tsk)
2700 and then Etype (Tsk) = S
2701 and then not (Comes_From_Source (S)))
2706 ("Attribute % must apply to entry of current task", N);
2712 elsif Ekind (Scope (Ent)) in Task_Kind
2713 and then Ekind (S) /= E_Loop
2714 and then Ekind (S) /= E_Block
2715 and then Ekind (S) /= E_Entry
2716 and then Ekind (S) /= E_Entry_Family
2718 Error_Attr ("Attribute % cannot appear in inner unit", N);
2720 elsif Ekind (Scope (Ent)) = E_Protected_Type
2721 and then not Has_Completion (Scope (Ent))
2723 Error_Attr ("attribute % can only be used inside body", N);
2727 if Is_Overloaded (P) then
2729 Index : Interp_Index;
2733 Get_First_Interp (P, Index, It);
2735 while Present (It.Nam) loop
2736 if It.Nam = Ent then
2739 -- Ada 2005 (AI-345): Do not consider primitive entry
2740 -- wrappers generated for task or protected types.
2742 elsif Ada_Version >= Ada_05
2743 and then not Comes_From_Source (It.Nam)
2748 Error_Attr ("ambiguous entry name", N);
2751 Get_Next_Interp (Index, It);
2756 Set_Etype (N, Universal_Integer);
2759 -----------------------
2760 -- Default_Bit_Order --
2761 -----------------------
2763 when Attribute_Default_Bit_Order => Default_Bit_Order :
2765 Check_Standard_Prefix;
2767 if Bytes_Big_Endian then
2769 Make_Integer_Literal (Loc, False_Value));
2772 Make_Integer_Literal (Loc, True_Value));
2775 Set_Etype (N, Universal_Integer);
2776 Set_Is_Static_Expression (N);
2777 end Default_Bit_Order;
2783 when Attribute_Definite =>
2784 Legal_Formal_Attribute;
2790 when Attribute_Delta =>
2791 Check_Fixed_Point_Type_0;
2792 Set_Etype (N, Universal_Real);
2798 when Attribute_Denorm =>
2799 Check_Floating_Point_Type_0;
2800 Set_Etype (N, Standard_Boolean);
2806 when Attribute_Digits =>
2810 if not Is_Floating_Point_Type (P_Type)
2811 and then not Is_Decimal_Fixed_Point_Type (P_Type)
2814 ("prefix of % attribute must be float or decimal type");
2817 Set_Etype (N, Universal_Integer);
2823 -- Also handles processing for Elab_Spec
2825 when Attribute_Elab_Body | Attribute_Elab_Spec =>
2827 Check_Unit_Name (P);
2828 Set_Etype (N, Standard_Void_Type);
2830 -- We have to manually call the expander in this case to get
2831 -- the necessary expansion (normally attributes that return
2832 -- entities are not expanded).
2840 -- Shares processing with Elab_Body
2846 when Attribute_Elaborated =>
2849 Set_Etype (N, Standard_Boolean);
2855 when Attribute_Emax =>
2856 Check_Floating_Point_Type_0;
2857 Set_Etype (N, Universal_Integer);
2863 when Attribute_Enabled =>
2864 Check_Either_E0_Or_E1;
2866 if Present (E1) then
2867 if not Is_Entity_Name (E1) or else No (Entity (E1)) then
2868 Error_Msg_N ("entity name expected for Enabled attribute", E1);
2873 if Nkind (P) /= N_Identifier then
2874 Error_Msg_N ("identifier expected (check name)", P);
2875 elsif Get_Check_Id (Chars (P)) = No_Check_Id then
2876 Error_Msg_N ("& is not a recognized check name", P);
2879 Set_Etype (N, Standard_Boolean);
2885 when Attribute_Enum_Rep => Enum_Rep : declare
2887 if Present (E1) then
2889 Check_Discrete_Type;
2890 Resolve (E1, P_Base_Type);
2893 if not Is_Entity_Name (P)
2894 or else (not Is_Object (Entity (P))
2896 Ekind (Entity (P)) /= E_Enumeration_Literal)
2899 ("prefix of %attribute must be " &
2900 "discrete type/object or enum literal");
2904 Set_Etype (N, Universal_Integer);
2911 when Attribute_Enum_Val => Enum_Val : begin
2915 if not Is_Enumeration_Type (P_Type) then
2916 Error_Attr_P ("prefix of % attribute must be enumeration type");
2919 -- If the enumeration type has a standard representation, the effect
2920 -- is the same as 'Val, so rewrite the attribute as a 'Val.
2922 if not Has_Non_Standard_Rep (P_Base_Type) then
2924 Make_Attribute_Reference (Loc,
2925 Prefix => Relocate_Node (Prefix (N)),
2926 Attribute_Name => Name_Val,
2927 Expressions => New_List (Relocate_Node (E1))));
2928 Analyze_And_Resolve (N, P_Base_Type);
2930 -- Non-standard representation case (enumeration with holes)
2934 Resolve (E1, Any_Integer);
2935 Set_Etype (N, P_Base_Type);
2943 when Attribute_Epsilon =>
2944 Check_Floating_Point_Type_0;
2945 Set_Etype (N, Universal_Real);
2951 when Attribute_Exponent =>
2952 Check_Floating_Point_Type_1;
2953 Set_Etype (N, Universal_Integer);
2954 Resolve (E1, P_Base_Type);
2960 when Attribute_External_Tag =>
2964 Set_Etype (N, Standard_String);
2966 if not Is_Tagged_Type (P_Type) then
2967 Error_Attr_P ("prefix of % attribute must be tagged");
2974 when Attribute_Fast_Math =>
2975 Check_Standard_Prefix;
2977 if Opt.Fast_Math then
2978 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
2980 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
2987 when Attribute_First =>
2988 Check_Array_Or_Scalar_Type;
2994 when Attribute_First_Bit =>
2996 Set_Etype (N, Universal_Integer);
3002 when Attribute_Fixed_Value =>
3004 Check_Fixed_Point_Type;
3005 Resolve (E1, Any_Integer);
3006 Set_Etype (N, P_Base_Type);
3012 when Attribute_Floor =>
3013 Check_Floating_Point_Type_1;
3014 Set_Etype (N, P_Base_Type);
3015 Resolve (E1, P_Base_Type);
3021 when Attribute_Fore =>
3022 Check_Fixed_Point_Type_0;
3023 Set_Etype (N, Universal_Integer);
3029 when Attribute_Fraction =>
3030 Check_Floating_Point_Type_1;
3031 Set_Etype (N, P_Base_Type);
3032 Resolve (E1, P_Base_Type);
3038 when Attribute_From_Any =>
3040 Check_PolyORB_Attribute;
3041 Set_Etype (N, P_Base_Type);
3043 -----------------------
3044 -- Has_Access_Values --
3045 -----------------------
3047 when Attribute_Has_Access_Values =>
3050 Set_Etype (N, Standard_Boolean);
3052 -----------------------
3053 -- Has_Tagged_Values --
3054 -----------------------
3056 when Attribute_Has_Tagged_Values =>
3059 Set_Etype (N, Standard_Boolean);
3061 -----------------------
3062 -- Has_Discriminants --
3063 -----------------------
3065 when Attribute_Has_Discriminants =>
3066 Legal_Formal_Attribute;
3072 when Attribute_Identity =>
3076 if Etype (P) = Standard_Exception_Type then
3077 Set_Etype (N, RTE (RE_Exception_Id));
3079 -- Ada 2005 (AI-345): Attribute 'Identity may be applied to
3080 -- task interface class-wide types.
3082 elsif Is_Task_Type (Etype (P))
3083 or else (Is_Access_Type (Etype (P))
3084 and then Is_Task_Type (Designated_Type (Etype (P))))
3085 or else (Ada_Version >= Ada_05
3086 and then Ekind (Etype (P)) = E_Class_Wide_Type
3087 and then Is_Interface (Etype (P))
3088 and then Is_Task_Interface (Etype (P)))
3091 Set_Etype (N, RTE (RO_AT_Task_Id));
3094 if Ada_Version >= Ada_05 then
3096 ("prefix of % attribute must be an exception, a " &
3097 "task or a task interface class-wide object");
3100 ("prefix of % attribute must be a task or an exception");
3108 when Attribute_Image => Image :
3110 Set_Etype (N, Standard_String);
3113 if Is_Real_Type (P_Type) then
3114 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
3115 Error_Msg_Name_1 := Aname;
3117 ("(Ada 83) % attribute not allowed for real types", N);
3121 if Is_Enumeration_Type (P_Type) then
3122 Check_Restriction (No_Enumeration_Maps, N);
3126 Resolve (E1, P_Base_Type);
3128 Validate_Non_Static_Attribute_Function_Call;
3135 when Attribute_Img => Img :
3138 Set_Etype (N, Standard_String);
3140 if not Is_Scalar_Type (P_Type)
3141 or else (Is_Entity_Name (P) and then Is_Type (Entity (P)))
3144 ("prefix of % attribute must be scalar object name");
3154 when Attribute_Input =>
3156 Check_Stream_Attribute (TSS_Stream_Input);
3157 Set_Etype (N, P_Base_Type);
3163 when Attribute_Integer_Value =>
3166 Resolve (E1, Any_Fixed);
3168 -- Signal an error if argument type is not a specific fixed-point
3169 -- subtype. An error has been signalled already if the argument
3170 -- was not of a fixed-point type.
3172 if Etype (E1) = Any_Fixed and then not Error_Posted (E1) then
3173 Error_Attr ("argument of % must be of a fixed-point type", E1);
3176 Set_Etype (N, P_Base_Type);
3182 when Attribute_Invalid_Value =>
3185 Set_Etype (N, P_Base_Type);
3186 Invalid_Value_Used := True;
3192 when Attribute_Large =>
3195 Set_Etype (N, Universal_Real);
3201 when Attribute_Last =>
3202 Check_Array_Or_Scalar_Type;
3208 when Attribute_Last_Bit =>
3210 Set_Etype (N, Universal_Integer);
3216 when Attribute_Leading_Part =>
3217 Check_Floating_Point_Type_2;
3218 Set_Etype (N, P_Base_Type);
3219 Resolve (E1, P_Base_Type);
3220 Resolve (E2, Any_Integer);
3226 when Attribute_Length =>
3228 Set_Etype (N, Universal_Integer);
3234 when Attribute_Machine =>
3235 Check_Floating_Point_Type_1;
3236 Set_Etype (N, P_Base_Type);
3237 Resolve (E1, P_Base_Type);
3243 when Attribute_Machine_Emax =>
3244 Check_Floating_Point_Type_0;
3245 Set_Etype (N, Universal_Integer);
3251 when Attribute_Machine_Emin =>
3252 Check_Floating_Point_Type_0;
3253 Set_Etype (N, Universal_Integer);
3255 ----------------------
3256 -- Machine_Mantissa --
3257 ----------------------
3259 when Attribute_Machine_Mantissa =>
3260 Check_Floating_Point_Type_0;
3261 Set_Etype (N, Universal_Integer);
3263 -----------------------
3264 -- Machine_Overflows --
3265 -----------------------
3267 when Attribute_Machine_Overflows =>
3270 Set_Etype (N, Standard_Boolean);
3276 when Attribute_Machine_Radix =>
3279 Set_Etype (N, Universal_Integer);
3281 ----------------------
3282 -- Machine_Rounding --
3283 ----------------------
3285 when Attribute_Machine_Rounding =>
3286 Check_Floating_Point_Type_1;
3287 Set_Etype (N, P_Base_Type);
3288 Resolve (E1, P_Base_Type);
3290 --------------------
3291 -- Machine_Rounds --
3292 --------------------
3294 when Attribute_Machine_Rounds =>
3297 Set_Etype (N, Standard_Boolean);
3303 when Attribute_Machine_Size =>
3306 Check_Not_Incomplete_Type;
3307 Set_Etype (N, Universal_Integer);
3313 when Attribute_Mantissa =>
3316 Set_Etype (N, Universal_Integer);
3322 when Attribute_Max =>
3325 Resolve (E1, P_Base_Type);
3326 Resolve (E2, P_Base_Type);
3327 Set_Etype (N, P_Base_Type);
3329 ----------------------------------
3330 -- Max_Size_In_Storage_Elements --
3331 ----------------------------------
3333 when Attribute_Max_Size_In_Storage_Elements =>
3336 Check_Not_Incomplete_Type;
3337 Set_Etype (N, Universal_Integer);
3339 -----------------------
3340 -- Maximum_Alignment --
3341 -----------------------
3343 when Attribute_Maximum_Alignment =>
3344 Standard_Attribute (Ttypes.Maximum_Alignment);
3346 --------------------
3347 -- Mechanism_Code --
3348 --------------------
3350 when Attribute_Mechanism_Code =>
3351 if not Is_Entity_Name (P)
3352 or else not Is_Subprogram (Entity (P))
3354 Error_Attr_P ("prefix of % attribute must be subprogram");
3357 Check_Either_E0_Or_E1;
3359 if Present (E1) then
3360 Resolve (E1, Any_Integer);
3361 Set_Etype (E1, Standard_Integer);
3363 if not Is_Static_Expression (E1) then
3364 Flag_Non_Static_Expr
3365 ("expression for parameter number must be static!", E1);
3368 elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P))
3369 or else UI_To_Int (Intval (E1)) < 0
3371 Error_Attr ("invalid parameter number for %attribute", E1);
3375 Set_Etype (N, Universal_Integer);
3381 when Attribute_Min =>
3384 Resolve (E1, P_Base_Type);
3385 Resolve (E2, P_Base_Type);
3386 Set_Etype (N, P_Base_Type);
3392 when Attribute_Mod =>
3394 -- Note: this attribute is only allowed in Ada 2005 mode, but
3395 -- we do not need to test that here, since Mod is only recognized
3396 -- as an attribute name in Ada 2005 mode during the parse.
3399 Check_Modular_Integer_Type;
3400 Resolve (E1, Any_Integer);
3401 Set_Etype (N, P_Base_Type);
3407 when Attribute_Model =>
3408 Check_Floating_Point_Type_1;
3409 Set_Etype (N, P_Base_Type);
3410 Resolve (E1, P_Base_Type);
3416 when Attribute_Model_Emin =>
3417 Check_Floating_Point_Type_0;
3418 Set_Etype (N, Universal_Integer);
3424 when Attribute_Model_Epsilon =>
3425 Check_Floating_Point_Type_0;
3426 Set_Etype (N, Universal_Real);
3428 --------------------
3429 -- Model_Mantissa --
3430 --------------------
3432 when Attribute_Model_Mantissa =>
3433 Check_Floating_Point_Type_0;
3434 Set_Etype (N, Universal_Integer);
3440 when Attribute_Model_Small =>
3441 Check_Floating_Point_Type_0;
3442 Set_Etype (N, Universal_Real);
3448 when Attribute_Modulus =>
3450 Check_Modular_Integer_Type;
3451 Set_Etype (N, Universal_Integer);
3453 --------------------
3454 -- Null_Parameter --
3455 --------------------
3457 when Attribute_Null_Parameter => Null_Parameter : declare
3458 Parnt : constant Node_Id := Parent (N);
3459 GParnt : constant Node_Id := Parent (Parnt);
3461 procedure Bad_Null_Parameter (Msg : String);
3462 -- Used if bad Null parameter attribute node is found. Issues
3463 -- given error message, and also sets the type to Any_Type to
3464 -- avoid blowups later on from dealing with a junk node.
3466 procedure Must_Be_Imported (Proc_Ent : Entity_Id);
3467 -- Called to check that Proc_Ent is imported subprogram
3469 ------------------------
3470 -- Bad_Null_Parameter --
3471 ------------------------
3473 procedure Bad_Null_Parameter (Msg : String) is
3475 Error_Msg_N (Msg, N);
3476 Set_Etype (N, Any_Type);
3477 end Bad_Null_Parameter;
3479 ----------------------
3480 -- Must_Be_Imported --
3481 ----------------------
3483 procedure Must_Be_Imported (Proc_Ent : Entity_Id) is
3484 Pent : Entity_Id := Proc_Ent;
3487 while Present (Alias (Pent)) loop
3488 Pent := Alias (Pent);
3491 -- Ignore check if procedure not frozen yet (we will get
3492 -- another chance when the default parameter is reanalyzed)
3494 if not Is_Frozen (Pent) then
3497 elsif not Is_Imported (Pent) then
3499 ("Null_Parameter can only be used with imported subprogram");
3504 end Must_Be_Imported;
3506 -- Start of processing for Null_Parameter
3511 Set_Etype (N, P_Type);
3513 -- Case of attribute used as default expression
3515 if Nkind (Parnt) = N_Parameter_Specification then
3516 Must_Be_Imported (Defining_Entity (GParnt));
3518 -- Case of attribute used as actual for subprogram (positional)
3520 elsif Nkind_In (Parnt, N_Procedure_Call_Statement,
3522 and then Is_Entity_Name (Name (Parnt))
3524 Must_Be_Imported (Entity (Name (Parnt)));
3526 -- Case of attribute used as actual for subprogram (named)
3528 elsif Nkind (Parnt) = N_Parameter_Association
3529 and then Nkind_In (GParnt, N_Procedure_Call_Statement,
3531 and then Is_Entity_Name (Name (GParnt))
3533 Must_Be_Imported (Entity (Name (GParnt)));
3535 -- Not an allowed case
3539 ("Null_Parameter must be actual or default parameter");
3547 when Attribute_Object_Size =>
3550 Check_Not_Incomplete_Type;
3551 Set_Etype (N, Universal_Integer);
3557 when Attribute_Old =>
3559 Set_Etype (N, P_Type);
3561 if No (Current_Subprogram) then
3562 Error_Attr ("attribute % can only appear within subprogram", N);
3565 if Is_Limited_Type (P_Type) then
3566 Error_Attr ("attribute % cannot apply to limited objects", P);
3569 if Is_Entity_Name (P)
3570 and then Is_Constant_Object (Entity (P))
3573 ("?attribute Old applied to constant has no effect", P);
3576 -- Check that the expression does not refer to local entities
3578 Check_Local : declare
3579 Subp : Entity_Id := Current_Subprogram;
3581 function Process (N : Node_Id) return Traverse_Result;
3582 -- Check that N does not contain references to local variables
3583 -- or other local entities of Subp.
3589 function Process (N : Node_Id) return Traverse_Result is
3591 if Is_Entity_Name (N)
3592 and then not Is_Formal (Entity (N))
3593 and then Enclosing_Subprogram (Entity (N)) = Subp
3595 Error_Msg_Node_1 := Entity (N);
3597 ("attribute % cannot refer to local variable&", N);
3603 procedure Check_No_Local is new Traverse_Proc;
3605 -- Start of processing for Check_Local
3610 if In_Parameter_Specification (P) then
3612 -- We have additional restrictions on using 'Old in parameter
3615 if Present (Enclosing_Subprogram (Current_Subprogram)) then
3617 -- Check that there is no reference to the enclosing
3618 -- subprogram local variables. Otherwise, we might end
3619 -- up being called from the enclosing subprogram and thus
3620 -- using 'Old on a local variable which is not defined
3623 Subp := Enclosing_Subprogram (Current_Subprogram);
3627 -- We must prevent default expression of library-level
3628 -- subprogram from using 'Old, as the subprogram may be
3629 -- used in elaboration code for which there is no enclosing
3633 ("attribute % can only appear within subprogram", N);
3642 when Attribute_Output =>
3644 Check_Stream_Attribute (TSS_Stream_Output);
3645 Set_Etype (N, Standard_Void_Type);
3646 Resolve (N, Standard_Void_Type);
3652 when Attribute_Partition_ID => Partition_Id :
3656 if P_Type /= Any_Type then
3657 if not Is_Library_Level_Entity (Entity (P)) then
3659 ("prefix of % attribute must be library-level entity");
3661 -- The defining entity of prefix should not be declared inside a
3662 -- Pure unit. RM E.1(8). Is_Pure was set during declaration.
3664 elsif Is_Entity_Name (P)
3665 and then Is_Pure (Entity (P))
3668 ("prefix of % attribute must not be declared pure");
3672 Set_Etype (N, Universal_Integer);
3675 -------------------------
3676 -- Passed_By_Reference --
3677 -------------------------
3679 when Attribute_Passed_By_Reference =>
3682 Set_Etype (N, Standard_Boolean);
3688 when Attribute_Pool_Address =>
3690 Set_Etype (N, RTE (RE_Address));
3696 when Attribute_Pos =>
3697 Check_Discrete_Type;
3699 Resolve (E1, P_Base_Type);
3700 Set_Etype (N, Universal_Integer);
3706 when Attribute_Position =>
3708 Set_Etype (N, Universal_Integer);
3714 when Attribute_Pred =>
3717 Resolve (E1, P_Base_Type);
3718 Set_Etype (N, P_Base_Type);
3720 -- Nothing to do for real type case
3722 if Is_Real_Type (P_Type) then
3725 -- If not modular type, test for overflow check required
3728 if not Is_Modular_Integer_Type (P_Type)
3729 and then not Range_Checks_Suppressed (P_Base_Type)
3731 Enable_Range_Check (E1);
3739 -- Ada 2005 (AI-327): Dynamic ceiling priorities
3741 when Attribute_Priority =>
3742 if Ada_Version < Ada_05 then
3743 Error_Attr ("% attribute is allowed only in Ada 2005 mode", P);
3748 -- The prefix must be a protected object (AARM D.5.2 (2/2))
3752 if Is_Protected_Type (Etype (P))
3753 or else (Is_Access_Type (Etype (P))
3754 and then Is_Protected_Type (Designated_Type (Etype (P))))
3756 Resolve (P, Etype (P));
3758 Error_Attr_P ("prefix of % attribute must be a protected object");
3761 Set_Etype (N, Standard_Integer);
3763 -- Must be called from within a protected procedure or entry of the
3764 -- protected object.
3771 while S /= Etype (P)
3772 and then S /= Standard_Standard
3777 if S = Standard_Standard then
3778 Error_Attr ("the attribute % is only allowed inside protected "
3783 Validate_Non_Static_Attribute_Function_Call;
3789 when Attribute_Range =>
3790 Check_Array_Or_Scalar_Type;
3792 if Ada_Version = Ada_83
3793 and then Is_Scalar_Type (P_Type)
3794 and then Comes_From_Source (N)
3797 ("(Ada 83) % attribute not allowed for scalar type", P);
3804 when Attribute_Result => Result : declare
3805 CS : Entity_Id := Current_Scope;
3806 PS : Entity_Id := Scope (CS);
3809 -- If the enclosing subprogram is always inlined, the enclosing
3810 -- postcondition will not be propagated to the expanded call.
3812 if Has_Pragma_Inline_Always (PS)
3813 and then Warn_On_Redundant_Constructs
3816 ("postconditions on inlined functions not enforced?", N);
3819 -- If we are in the scope of a function and in Spec_Expression mode,
3820 -- this is likely the prescan of the postcondition pragma, and we
3821 -- just set the proper type. If there is an error it will be caught
3822 -- when the real Analyze call is done.
3824 if Ekind (CS) = E_Function
3825 and then In_Spec_Expression
3829 if Chars (CS) /= Chars (P) then
3831 ("incorrect prefix for % attribute, expected &", P, CS);
3835 Set_Etype (N, Etype (CS));
3837 -- If several functions with that name are visible,
3838 -- the intended one is the current scope.
3840 if Is_Overloaded (P) then
3842 Set_Is_Overloaded (P, False);
3845 -- Body case, where we must be inside a generated _Postcondition
3846 -- procedure, and the prefix must be on the scope stack, or else
3847 -- the attribute use is definitely misplaced. The condition itself
3848 -- may have generated transient scopes, and is not necessarily the
3853 and then CS /= Standard_Standard
3855 if Chars (CS) = Name_uPostconditions then
3864 if Chars (CS) = Name_uPostconditions
3865 and then Ekind (PS) = E_Function
3869 if Nkind_In (P, N_Identifier, N_Operator_Symbol)
3870 and then Chars (P) = Chars (PS)
3874 -- Within an instance, the prefix designates the local renaming
3875 -- of the original generic.
3877 elsif Is_Entity_Name (P)
3878 and then Ekind (Entity (P)) = E_Function
3879 and then Present (Alias (Entity (P)))
3880 and then Chars (Alias (Entity (P))) = Chars (PS)
3886 ("incorrect prefix for % attribute, expected &", P, PS);
3891 Make_Identifier (Sloc (N),
3892 Chars => Name_uResult));
3893 Analyze_And_Resolve (N, Etype (PS));
3897 ("% attribute can only appear" &
3898 " in function Postcondition pragma", P);
3907 when Attribute_Range_Length =>
3909 Check_Discrete_Type;
3910 Set_Etype (N, Universal_Integer);
3916 when Attribute_Read =>
3918 Check_Stream_Attribute (TSS_Stream_Read);
3919 Set_Etype (N, Standard_Void_Type);
3920 Resolve (N, Standard_Void_Type);
3921 Note_Possible_Modification (E2, Sure => True);
3927 when Attribute_Remainder =>
3928 Check_Floating_Point_Type_2;
3929 Set_Etype (N, P_Base_Type);
3930 Resolve (E1, P_Base_Type);
3931 Resolve (E2, P_Base_Type);
3937 when Attribute_Round =>
3939 Check_Decimal_Fixed_Point_Type;
3940 Set_Etype (N, P_Base_Type);
3942 -- Because the context is universal_real (3.5.10(12)) it is a legal
3943 -- context for a universal fixed expression. This is the only
3944 -- attribute whose functional description involves U_R.
3946 if Etype (E1) = Universal_Fixed then
3948 Conv : constant Node_Id := Make_Type_Conversion (Loc,
3949 Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc),
3950 Expression => Relocate_Node (E1));
3958 Resolve (E1, Any_Real);
3964 when Attribute_Rounding =>
3965 Check_Floating_Point_Type_1;
3966 Set_Etype (N, P_Base_Type);
3967 Resolve (E1, P_Base_Type);
3973 when Attribute_Safe_Emax =>
3974 Check_Floating_Point_Type_0;
3975 Set_Etype (N, Universal_Integer);
3981 when Attribute_Safe_First =>
3982 Check_Floating_Point_Type_0;
3983 Set_Etype (N, Universal_Real);
3989 when Attribute_Safe_Large =>
3992 Set_Etype (N, Universal_Real);
3998 when Attribute_Safe_Last =>
3999 Check_Floating_Point_Type_0;
4000 Set_Etype (N, Universal_Real);
4006 when Attribute_Safe_Small =>
4009 Set_Etype (N, Universal_Real);
4015 when Attribute_Scale =>
4017 Check_Decimal_Fixed_Point_Type;
4018 Set_Etype (N, Universal_Integer);
4024 when Attribute_Scaling =>
4025 Check_Floating_Point_Type_2;
4026 Set_Etype (N, P_Base_Type);
4027 Resolve (E1, P_Base_Type);
4033 when Attribute_Signed_Zeros =>
4034 Check_Floating_Point_Type_0;
4035 Set_Etype (N, Standard_Boolean);
4041 when Attribute_Size | Attribute_VADS_Size => Size :
4045 -- If prefix is parameterless function call, rewrite and resolve
4048 if Is_Entity_Name (P)
4049 and then Ekind (Entity (P)) = E_Function
4053 -- Similar processing for a protected function call
4055 elsif Nkind (P) = N_Selected_Component
4056 and then Ekind (Entity (Selector_Name (P))) = E_Function
4061 if Is_Object_Reference (P) then
4062 Check_Object_Reference (P);
4064 elsif Is_Entity_Name (P)
4065 and then (Is_Type (Entity (P))
4066 or else Ekind (Entity (P)) = E_Enumeration_Literal)
4070 elsif Nkind (P) = N_Type_Conversion
4071 and then not Comes_From_Source (P)
4076 Error_Attr_P ("invalid prefix for % attribute");
4079 Check_Not_Incomplete_Type;
4081 Set_Etype (N, Universal_Integer);
4088 when Attribute_Small =>
4091 Set_Etype (N, Universal_Real);
4097 when Attribute_Storage_Pool => Storage_Pool :
4101 if Is_Access_Type (P_Type) then
4102 if Ekind (P_Type) = E_Access_Subprogram_Type then
4104 ("cannot use % attribute for access-to-subprogram type");
4107 -- Set appropriate entity
4109 if Present (Associated_Storage_Pool (Root_Type (P_Type))) then
4110 Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type)));
4112 Set_Entity (N, RTE (RE_Global_Pool_Object));
4115 Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
4117 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4118 -- Storage_Pool since this attribute is not defined for such
4119 -- types (RM E.2.3(22)).
4121 Validate_Remote_Access_To_Class_Wide_Type (N);
4124 Error_Attr_P ("prefix of % attribute must be access type");
4132 when Attribute_Storage_Size => Storage_Size :
4136 if Is_Task_Type (P_Type) then
4137 Set_Etype (N, Universal_Integer);
4139 elsif Is_Access_Type (P_Type) then
4140 if Ekind (P_Type) = E_Access_Subprogram_Type then
4142 ("cannot use % attribute for access-to-subprogram type");
4145 if Is_Entity_Name (P)
4146 and then Is_Type (Entity (P))
4149 Set_Etype (N, Universal_Integer);
4151 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
4152 -- Storage_Size since this attribute is not defined for
4153 -- such types (RM E.2.3(22)).
4155 Validate_Remote_Access_To_Class_Wide_Type (N);
4157 -- The prefix is allowed to be an implicit dereference
4158 -- of an access value designating a task.
4162 Set_Etype (N, Universal_Integer);
4166 Error_Attr_P ("prefix of % attribute must be access or task type");
4174 when Attribute_Storage_Unit =>
4175 Standard_Attribute (Ttypes.System_Storage_Unit);
4181 when Attribute_Stream_Size =>
4185 if Is_Entity_Name (P)
4186 and then Is_Elementary_Type (Entity (P))
4188 Set_Etype (N, Universal_Integer);
4190 Error_Attr_P ("invalid prefix for % attribute");
4197 when Attribute_Stub_Type =>
4201 if Is_Remote_Access_To_Class_Wide_Type (P_Type) then
4203 New_Occurrence_Of (Corresponding_Stub_Type (P_Type), Loc));
4206 ("prefix of% attribute must be remote access to classwide");
4213 when Attribute_Succ =>
4216 Resolve (E1, P_Base_Type);
4217 Set_Etype (N, P_Base_Type);
4219 -- Nothing to do for real type case
4221 if Is_Real_Type (P_Type) then
4224 -- If not modular type, test for overflow check required
4227 if not Is_Modular_Integer_Type (P_Type)
4228 and then not Range_Checks_Suppressed (P_Base_Type)
4230 Enable_Range_Check (E1);
4238 when Attribute_Tag => Tag :
4243 if not Is_Tagged_Type (P_Type) then
4244 Error_Attr_P ("prefix of % attribute must be tagged");
4246 -- Next test does not apply to generated code
4247 -- why not, and what does the illegal reference mean???
4249 elsif Is_Object_Reference (P)
4250 and then not Is_Class_Wide_Type (P_Type)
4251 and then Comes_From_Source (N)
4254 ("% attribute can only be applied to objects " &
4255 "of class - wide type");
4258 -- The prefix cannot be an incomplete type. However, references
4259 -- to 'Tag can be generated when expanding interface conversions,
4260 -- and this is legal.
4262 if Comes_From_Source (N) then
4263 Check_Not_Incomplete_Type;
4266 -- Set appropriate type
4268 Set_Etype (N, RTE (RE_Tag));
4275 when Attribute_Target_Name => Target_Name : declare
4276 TN : constant String := Sdefault.Target_Name.all;
4280 Check_Standard_Prefix;
4284 if TN (TL) = '/' or else TN (TL) = '\' then
4289 Make_String_Literal (Loc,
4290 Strval => TN (TN'First .. TL)));
4291 Analyze_And_Resolve (N, Standard_String);
4298 when Attribute_Terminated =>
4300 Set_Etype (N, Standard_Boolean);
4307 when Attribute_To_Address =>
4311 if Nkind (P) /= N_Identifier
4312 or else Chars (P) /= Name_System
4314 Error_Attr_P ("prefix of %attribute must be System");
4317 Generate_Reference (RTE (RE_Address), P);
4318 Analyze_And_Resolve (E1, Any_Integer);
4319 Set_Etype (N, RTE (RE_Address));
4325 when Attribute_To_Any =>
4327 Check_PolyORB_Attribute;
4328 Set_Etype (N, RTE (RE_Any));
4334 when Attribute_Truncation =>
4335 Check_Floating_Point_Type_1;
4336 Resolve (E1, P_Base_Type);
4337 Set_Etype (N, P_Base_Type);
4343 when Attribute_Type_Class =>
4346 Check_Not_Incomplete_Type;
4347 Set_Etype (N, RTE (RE_Type_Class));
4353 when Attribute_TypeCode =>
4355 Check_PolyORB_Attribute;
4356 Set_Etype (N, RTE (RE_TypeCode));
4362 when Attribute_UET_Address =>
4364 Check_Unit_Name (P);
4365 Set_Etype (N, RTE (RE_Address));
4367 -----------------------
4368 -- Unbiased_Rounding --
4369 -----------------------
4371 when Attribute_Unbiased_Rounding =>
4372 Check_Floating_Point_Type_1;
4373 Set_Etype (N, P_Base_Type);
4374 Resolve (E1, P_Base_Type);
4376 ----------------------
4377 -- Unchecked_Access --
4378 ----------------------
4380 when Attribute_Unchecked_Access =>
4381 if Comes_From_Source (N) then
4382 Check_Restriction (No_Unchecked_Access, N);
4385 Analyze_Access_Attribute;
4387 -------------------------
4388 -- Unconstrained_Array --
4389 -------------------------
4391 when Attribute_Unconstrained_Array =>
4394 Check_Not_Incomplete_Type;
4395 Set_Etype (N, Standard_Boolean);
4397 ------------------------------
4398 -- Universal_Literal_String --
4399 ------------------------------
4401 -- This is a GNAT specific attribute whose prefix must be a named
4402 -- number where the expression is either a single numeric literal,
4403 -- or a numeric literal immediately preceded by a minus sign. The
4404 -- result is equivalent to a string literal containing the text of
4405 -- the literal as it appeared in the source program with a possible
4406 -- leading minus sign.
4408 when Attribute_Universal_Literal_String => Universal_Literal_String :
4412 if not Is_Entity_Name (P)
4413 or else Ekind (Entity (P)) not in Named_Kind
4415 Error_Attr_P ("prefix for % attribute must be named number");
4422 Src : Source_Buffer_Ptr;
4425 Expr := Original_Node (Expression (Parent (Entity (P))));
4427 if Nkind (Expr) = N_Op_Minus then
4429 Expr := Original_Node (Right_Opnd (Expr));
4434 if not Nkind_In (Expr, N_Integer_Literal, N_Real_Literal) then
4436 ("named number for % attribute must be simple literal", N);
4439 -- Build string literal corresponding to source literal text
4444 Store_String_Char (Get_Char_Code ('-'));
4448 Src := Source_Text (Get_Source_File_Index (S));
4450 while Src (S) /= ';' and then Src (S) /= ' ' loop
4451 Store_String_Char (Get_Char_Code (Src (S)));
4455 -- Now we rewrite the attribute with the string literal
4458 Make_String_Literal (Loc, End_String));
4462 end Universal_Literal_String;
4464 -------------------------
4465 -- Unrestricted_Access --
4466 -------------------------
4468 -- This is a GNAT specific attribute which is like Access except that
4469 -- all scope checks and checks for aliased views are omitted.
4471 when Attribute_Unrestricted_Access =>
4472 if Comes_From_Source (N) then
4473 Check_Restriction (No_Unchecked_Access, N);
4476 if Is_Entity_Name (P) then
4477 Set_Address_Taken (Entity (P));
4480 Analyze_Access_Attribute;
4486 when Attribute_Val => Val : declare
4489 Check_Discrete_Type;
4490 Resolve (E1, Any_Integer);
4491 Set_Etype (N, P_Base_Type);
4493 -- Note, we need a range check in general, but we wait for the
4494 -- Resolve call to do this, since we want to let Eval_Attribute
4495 -- have a chance to find an static illegality first!
4502 when Attribute_Valid =>
4505 -- Ignore check for object if we have a 'Valid reference generated
4506 -- by the expanded code, since in some cases valid checks can occur
4507 -- on items that are names, but are not objects (e.g. attributes).
4509 if Comes_From_Source (N) then
4510 Check_Object_Reference (P);
4513 if not Is_Scalar_Type (P_Type) then
4514 Error_Attr_P ("object for % attribute must be of scalar type");
4517 Set_Etype (N, Standard_Boolean);
4523 when Attribute_Value => Value :
4528 -- Case of enumeration type
4530 if Is_Enumeration_Type (P_Type) then
4531 Check_Restriction (No_Enumeration_Maps, N);
4533 -- Mark all enumeration literals as referenced, since the use of
4534 -- the Value attribute can implicitly reference any of the
4535 -- literals of the enumeration base type.
4538 Ent : Entity_Id := First_Literal (P_Base_Type);
4540 while Present (Ent) loop
4541 Set_Referenced (Ent);
4547 -- Set Etype before resolving expression because expansion of
4548 -- expression may require enclosing type. Note that the type
4549 -- returned by 'Value is the base type of the prefix type.
4551 Set_Etype (N, P_Base_Type);
4552 Validate_Non_Static_Attribute_Function_Call;
4559 when Attribute_Value_Size =>
4562 Check_Not_Incomplete_Type;
4563 Set_Etype (N, Universal_Integer);
4569 when Attribute_Version =>
4572 Set_Etype (N, RTE (RE_Version_String));
4578 when Attribute_Wchar_T_Size =>
4579 Standard_Attribute (Interfaces_Wchar_T_Size);
4585 when Attribute_Wide_Image => Wide_Image :
4588 Set_Etype (N, Standard_Wide_String);
4590 Resolve (E1, P_Base_Type);
4591 Validate_Non_Static_Attribute_Function_Call;
4594 ---------------------
4595 -- Wide_Wide_Image --
4596 ---------------------
4598 when Attribute_Wide_Wide_Image => Wide_Wide_Image :
4601 Set_Etype (N, Standard_Wide_Wide_String);
4603 Resolve (E1, P_Base_Type);
4604 Validate_Non_Static_Attribute_Function_Call;
4605 end Wide_Wide_Image;
4611 when Attribute_Wide_Value => Wide_Value :
4616 -- Set Etype before resolving expression because expansion
4617 -- of expression may require enclosing type.
4619 Set_Etype (N, P_Type);
4620 Validate_Non_Static_Attribute_Function_Call;
4623 ---------------------
4624 -- Wide_Wide_Value --
4625 ---------------------
4627 when Attribute_Wide_Wide_Value => Wide_Wide_Value :
4632 -- Set Etype before resolving expression because expansion
4633 -- of expression may require enclosing type.
4635 Set_Etype (N, P_Type);
4636 Validate_Non_Static_Attribute_Function_Call;
4637 end Wide_Wide_Value;
4639 ---------------------
4640 -- Wide_Wide_Width --
4641 ---------------------
4643 when Attribute_Wide_Wide_Width =>
4646 Set_Etype (N, Universal_Integer);
4652 when Attribute_Wide_Width =>
4655 Set_Etype (N, Universal_Integer);
4661 when Attribute_Width =>
4664 Set_Etype (N, Universal_Integer);
4670 when Attribute_Word_Size =>
4671 Standard_Attribute (System_Word_Size);
4677 when Attribute_Write =>
4679 Check_Stream_Attribute (TSS_Stream_Write);
4680 Set_Etype (N, Standard_Void_Type);
4681 Resolve (N, Standard_Void_Type);
4685 -- All errors raise Bad_Attribute, so that we get out before any further
4686 -- damage occurs when an error is detected (for example, if we check for
4687 -- one attribute expression, and the check succeeds, we want to be able
4688 -- to proceed securely assuming that an expression is in fact present.
4690 -- Note: we set the attribute analyzed in this case to prevent any
4691 -- attempt at reanalysis which could generate spurious error msgs.
4694 when Bad_Attribute =>
4696 Set_Etype (N, Any_Type);
4698 end Analyze_Attribute;
4700 --------------------
4701 -- Eval_Attribute --
4702 --------------------
4704 procedure Eval_Attribute (N : Node_Id) is
4705 Loc : constant Source_Ptr := Sloc (N);
4706 Aname : constant Name_Id := Attribute_Name (N);
4707 Id : constant Attribute_Id := Get_Attribute_Id (Aname);
4708 P : constant Node_Id := Prefix (N);
4710 C_Type : constant Entity_Id := Etype (N);
4711 -- The type imposed by the context
4714 -- First expression, or Empty if none
4717 -- Second expression, or Empty if none
4719 P_Entity : Entity_Id;
4720 -- Entity denoted by prefix
4723 -- The type of the prefix
4725 P_Base_Type : Entity_Id;
4726 -- The base type of the prefix type
4728 P_Root_Type : Entity_Id;
4729 -- The root type of the prefix type
4732 -- True if the result is Static. This is set by the general processing
4733 -- to true if the prefix is static, and all expressions are static. It
4734 -- can be reset as processing continues for particular attributes
4736 Lo_Bound, Hi_Bound : Node_Id;
4737 -- Expressions for low and high bounds of type or array index referenced
4738 -- by First, Last, or Length attribute for array, set by Set_Bounds.
4741 -- Constraint error node used if we have an attribute reference has
4742 -- an argument that raises a constraint error. In this case we replace
4743 -- the attribute with a raise constraint_error node. This is important
4744 -- processing, since otherwise gigi might see an attribute which it is
4745 -- unprepared to deal with.
4747 function Aft_Value return Nat;
4748 -- Computes Aft value for current attribute prefix (used by Aft itself
4749 -- and also by Width for computing the Width of a fixed point type).
4751 procedure Check_Expressions;
4752 -- In case where the attribute is not foldable, the expressions, if
4753 -- any, of the attribute, are in a non-static context. This procedure
4754 -- performs the required additional checks.
4756 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean;
4757 -- Determines if the given type has compile time known bounds. Note
4758 -- that we enter the case statement even in cases where the prefix
4759 -- type does NOT have known bounds, so it is important to guard any
4760 -- attempt to evaluate both bounds with a call to this function.
4762 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint);
4763 -- This procedure is called when the attribute N has a non-static
4764 -- but compile time known value given by Val. It includes the
4765 -- necessary checks for out of range values.
4767 procedure Float_Attribute_Universal_Integer
4776 -- This procedure evaluates a float attribute with no arguments that
4777 -- returns a universal integer result. The parameters give the values
4778 -- for the possible floating-point root types. See ttypef for details.
4779 -- The prefix type is a float type (and is thus not a generic type).
4781 procedure Float_Attribute_Universal_Real
4782 (IEEES_Val : String;
4789 AAMPL_Val : String);
4790 -- This procedure evaluates a float attribute with no arguments that
4791 -- returns a universal real result. The parameters give the values
4792 -- required for the possible floating-point root types in string
4793 -- format as real literals with a possible leading minus sign.
4794 -- The prefix type is a float type (and is thus not a generic type).
4796 function Fore_Value return Nat;
4797 -- Computes the Fore value for the current attribute prefix, which is
4798 -- known to be a static fixed-point type. Used by Fore and Width.
4800 function Mantissa return Uint;
4801 -- Returns the Mantissa value for the prefix type
4803 procedure Set_Bounds;
4804 -- Used for First, Last and Length attributes applied to an array or
4805 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
4806 -- and high bound expressions for the index referenced by the attribute
4807 -- designator (i.e. the first index if no expression is present, and
4808 -- the N'th index if the value N is present as an expression). Also
4809 -- used for First and Last of scalar types. Static is reset to False
4810 -- if the type or index type is not statically constrained.
4812 function Statically_Denotes_Entity (N : Node_Id) return Boolean;
4813 -- Verify that the prefix of a potentially static array attribute
4814 -- satisfies the conditions of 4.9 (14).
4820 function Aft_Value return Nat is
4826 Delta_Val := Delta_Value (P_Type);
4827 while Delta_Val < Ureal_Tenth loop
4828 Delta_Val := Delta_Val * Ureal_10;
4829 Result := Result + 1;
4835 -----------------------
4836 -- Check_Expressions --
4837 -----------------------
4839 procedure Check_Expressions is
4843 while Present (E) loop
4844 Check_Non_Static_Context (E);
4847 end Check_Expressions;
4849 ----------------------------------
4850 -- Compile_Time_Known_Attribute --
4851 ----------------------------------
4853 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is
4854 T : constant Entity_Id := Etype (N);
4857 Fold_Uint (N, Val, False);
4859 -- Check that result is in bounds of the type if it is static
4861 if Is_In_Range (N, T, Assume_Valid => False) then
4864 elsif Is_Out_Of_Range (N, T) then
4865 Apply_Compile_Time_Constraint_Error
4866 (N, "value not in range of}?", CE_Range_Check_Failed);
4868 elsif not Range_Checks_Suppressed (T) then
4869 Enable_Range_Check (N);
4872 Set_Do_Range_Check (N, False);
4874 end Compile_Time_Known_Attribute;
4876 -------------------------------
4877 -- Compile_Time_Known_Bounds --
4878 -------------------------------
4880 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is
4883 Compile_Time_Known_Value (Type_Low_Bound (Typ))
4885 Compile_Time_Known_Value (Type_High_Bound (Typ));
4886 end Compile_Time_Known_Bounds;
4888 ---------------------------------------
4889 -- Float_Attribute_Universal_Integer --
4890 ---------------------------------------
4892 procedure Float_Attribute_Universal_Integer
4903 Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type));
4906 if Vax_Float (P_Base_Type) then
4907 if Digs = VAXFF_Digits then
4909 elsif Digs = VAXDF_Digits then
4911 else pragma Assert (Digs = VAXGF_Digits);
4915 elsif Is_AAMP_Float (P_Base_Type) then
4916 if Digs = AAMPS_Digits then
4918 else pragma Assert (Digs = AAMPL_Digits);
4923 if Digs = IEEES_Digits then
4925 elsif Digs = IEEEL_Digits then
4927 else pragma Assert (Digs = IEEEX_Digits);
4932 Fold_Uint (N, UI_From_Int (Val), True);
4933 end Float_Attribute_Universal_Integer;
4935 ------------------------------------
4936 -- Float_Attribute_Universal_Real --
4937 ------------------------------------
4939 procedure Float_Attribute_Universal_Real
4940 (IEEES_Val : String;
4950 Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type));
4953 if Vax_Float (P_Base_Type) then
4954 if Digs = VAXFF_Digits then
4955 Val := Real_Convert (VAXFF_Val);
4956 elsif Digs = VAXDF_Digits then
4957 Val := Real_Convert (VAXDF_Val);
4958 else pragma Assert (Digs = VAXGF_Digits);
4959 Val := Real_Convert (VAXGF_Val);
4962 elsif Is_AAMP_Float (P_Base_Type) then
4963 if Digs = AAMPS_Digits then
4964 Val := Real_Convert (AAMPS_Val);
4965 else pragma Assert (Digs = AAMPL_Digits);
4966 Val := Real_Convert (AAMPL_Val);
4970 if Digs = IEEES_Digits then
4971 Val := Real_Convert (IEEES_Val);
4972 elsif Digs = IEEEL_Digits then
4973 Val := Real_Convert (IEEEL_Val);
4974 else pragma Assert (Digs = IEEEX_Digits);
4975 Val := Real_Convert (IEEEX_Val);
4979 Set_Sloc (Val, Loc);
4981 Set_Is_Static_Expression (N, Static);
4982 Analyze_And_Resolve (N, C_Type);
4983 end Float_Attribute_Universal_Real;
4989 -- Note that the Fore calculation is based on the actual values
4990 -- of the bounds, and does not take into account possible rounding.
4992 function Fore_Value return Nat is
4993 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
4994 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
4995 Small : constant Ureal := Small_Value (P_Type);
4996 Lo_Real : constant Ureal := Lo * Small;
4997 Hi_Real : constant Ureal := Hi * Small;
5002 -- Bounds are given in terms of small units, so first compute
5003 -- proper values as reals.
5005 T := UR_Max (abs Lo_Real, abs Hi_Real);
5008 -- Loop to compute proper value if more than one digit required
5010 while T >= Ureal_10 loop
5022 -- Table of mantissa values accessed by function Computed using
5025 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
5027 -- where D is T'Digits (RM83 3.5.7)
5029 Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := (
5071 function Mantissa return Uint is
5074 UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type))));
5081 procedure Set_Bounds is
5087 -- For a string literal subtype, we have to construct the bounds.
5088 -- Valid Ada code never applies attributes to string literals, but
5089 -- it is convenient to allow the expander to generate attribute
5090 -- references of this type (e.g. First and Last applied to a string
5093 -- Note that the whole point of the E_String_Literal_Subtype is to
5094 -- avoid this construction of bounds, but the cases in which we
5095 -- have to materialize them are rare enough that we don't worry!
5097 -- The low bound is simply the low bound of the base type. The
5098 -- high bound is computed from the length of the string and this
5101 if Ekind (P_Type) = E_String_Literal_Subtype then
5102 Ityp := Etype (First_Index (Base_Type (P_Type)));
5103 Lo_Bound := Type_Low_Bound (Ityp);
5106 Make_Integer_Literal (Sloc (P),
5108 Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1);
5110 Set_Parent (Hi_Bound, P);
5111 Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound));
5114 -- For non-array case, just get bounds of scalar type
5116 elsif Is_Scalar_Type (P_Type) then
5119 -- For a fixed-point type, we must freeze to get the attributes
5120 -- of the fixed-point type set now so we can reference them.
5122 if Is_Fixed_Point_Type (P_Type)
5123 and then not Is_Frozen (Base_Type (P_Type))
5124 and then Compile_Time_Known_Value (Type_Low_Bound (P_Type))
5125 and then Compile_Time_Known_Value (Type_High_Bound (P_Type))
5127 Freeze_Fixed_Point_Type (Base_Type (P_Type));
5130 -- For array case, get type of proper index
5136 Ndim := UI_To_Int (Expr_Value (E1));
5139 Indx := First_Index (P_Type);
5140 for J in 1 .. Ndim - 1 loop
5144 -- If no index type, get out (some other error occurred, and
5145 -- we don't have enough information to complete the job!)
5153 Ityp := Etype (Indx);
5156 -- A discrete range in an index constraint is allowed to be a
5157 -- subtype indication. This is syntactically a pain, but should
5158 -- not propagate to the entity for the corresponding index subtype.
5159 -- After checking that the subtype indication is legal, the range
5160 -- of the subtype indication should be transfered to the entity.
5161 -- The attributes for the bounds should remain the simple retrievals
5162 -- that they are now.
5164 Lo_Bound := Type_Low_Bound (Ityp);
5165 Hi_Bound := Type_High_Bound (Ityp);
5167 if not Is_Static_Subtype (Ityp) then
5172 -------------------------------
5173 -- Statically_Denotes_Entity --
5174 -------------------------------
5176 function Statically_Denotes_Entity (N : Node_Id) return Boolean is
5180 if not Is_Entity_Name (N) then
5187 Nkind (Parent (E)) /= N_Object_Renaming_Declaration
5188 or else Statically_Denotes_Entity (Renamed_Object (E));
5189 end Statically_Denotes_Entity;
5191 -- Start of processing for Eval_Attribute
5194 -- Acquire first two expressions (at the moment, no attributes
5195 -- take more than two expressions in any case).
5197 if Present (Expressions (N)) then
5198 E1 := First (Expressions (N));
5205 -- Special processing for Enabled attribute. This attribute has a very
5206 -- special prefix, and the easiest way to avoid lots of special checks
5207 -- to protect this special prefix from causing trouble is to deal with
5208 -- this attribute immediately and be done with it.
5210 if Id = Attribute_Enabled then
5212 -- Evaluate the Enabled attribute
5214 -- We skip evaluation if the expander is not active. This is not just
5215 -- an optimization. It is of key importance that we not rewrite the
5216 -- attribute in a generic template, since we want to pick up the
5217 -- setting of the check in the instance, and testing expander active
5218 -- is as easy way of doing this as any.
5220 if Expander_Active then
5222 C : constant Check_Id := Get_Check_Id (Chars (P));
5227 if C in Predefined_Check_Id then
5228 R := Scope_Suppress (C);
5230 R := Is_Check_Suppressed (Empty, C);
5234 R := Is_Check_Suppressed (Entity (E1), C);
5238 Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
5240 Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
5248 -- Special processing for cases where the prefix is an object. For
5249 -- this purpose, a string literal counts as an object (attributes
5250 -- of string literals can only appear in generated code).
5252 if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal then
5254 -- For Component_Size, the prefix is an array object, and we apply
5255 -- the attribute to the type of the object. This is allowed for
5256 -- both unconstrained and constrained arrays, since the bounds
5257 -- have no influence on the value of this attribute.
5259 if Id = Attribute_Component_Size then
5260 P_Entity := Etype (P);
5262 -- For First and Last, the prefix is an array object, and we apply
5263 -- the attribute to the type of the array, but we need a constrained
5264 -- type for this, so we use the actual subtype if available.
5266 elsif Id = Attribute_First
5270 Id = Attribute_Length
5273 AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P);
5276 if Present (AS) and then Is_Constrained (AS) then
5279 -- If we have an unconstrained type we cannot fold
5287 -- For Size, give size of object if available, otherwise we
5288 -- cannot fold Size.
5290 elsif Id = Attribute_Size then
5291 if Is_Entity_Name (P)
5292 and then Known_Esize (Entity (P))
5294 Compile_Time_Known_Attribute (N, Esize (Entity (P)));
5302 -- For Alignment, give size of object if available, otherwise we
5303 -- cannot fold Alignment.
5305 elsif Id = Attribute_Alignment then
5306 if Is_Entity_Name (P)
5307 and then Known_Alignment (Entity (P))
5309 Fold_Uint (N, Alignment (Entity (P)), False);
5317 -- No other attributes for objects are folded
5324 -- Cases where P is not an object. Cannot do anything if P is
5325 -- not the name of an entity.
5327 elsif not Is_Entity_Name (P) then
5331 -- Otherwise get prefix entity
5334 P_Entity := Entity (P);
5337 -- At this stage P_Entity is the entity to which the attribute
5338 -- is to be applied. This is usually simply the entity of the
5339 -- prefix, except in some cases of attributes for objects, where
5340 -- as described above, we apply the attribute to the object type.
5342 -- First foldable possibility is a scalar or array type (RM 4.9(7))
5343 -- that is not generic (generic types are eliminated by RM 4.9(25)).
5344 -- Note we allow non-static non-generic types at this stage as further
5347 if Is_Type (P_Entity)
5348 and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
5349 and then (not Is_Generic_Type (P_Entity))
5353 -- Second foldable possibility is an array object (RM 4.9(8))
5355 elsif (Ekind (P_Entity) = E_Variable
5357 Ekind (P_Entity) = E_Constant)
5358 and then Is_Array_Type (Etype (P_Entity))
5359 and then (not Is_Generic_Type (Etype (P_Entity)))
5361 P_Type := Etype (P_Entity);
5363 -- If the entity is an array constant with an unconstrained nominal
5364 -- subtype then get the type from the initial value. If the value has
5365 -- been expanded into assignments, there is no expression and the
5366 -- attribute reference remains dynamic.
5368 -- We could do better here and retrieve the type ???
5370 if Ekind (P_Entity) = E_Constant
5371 and then not Is_Constrained (P_Type)
5373 if No (Constant_Value (P_Entity)) then
5376 P_Type := Etype (Constant_Value (P_Entity));
5380 -- Definite must be folded if the prefix is not a generic type,
5381 -- that is to say if we are within an instantiation. Same processing
5382 -- applies to the GNAT attributes Has_Discriminants, Type_Class,
5383 -- Has_Tagged_Value, and Unconstrained_Array.
5385 elsif (Id = Attribute_Definite
5387 Id = Attribute_Has_Access_Values
5389 Id = Attribute_Has_Discriminants
5391 Id = Attribute_Has_Tagged_Values
5393 Id = Attribute_Type_Class
5395 Id = Attribute_Unconstrained_Array)
5396 and then not Is_Generic_Type (P_Entity)
5400 -- We can fold 'Size applied to a type if the size is known (as happens
5401 -- for a size from an attribute definition clause). At this stage, this
5402 -- can happen only for types (e.g. record types) for which the size is
5403 -- always non-static. We exclude generic types from consideration (since
5404 -- they have bogus sizes set within templates).
5406 elsif Id = Attribute_Size
5407 and then Is_Type (P_Entity)
5408 and then (not Is_Generic_Type (P_Entity))
5409 and then Known_Static_RM_Size (P_Entity)
5411 Compile_Time_Known_Attribute (N, RM_Size (P_Entity));
5414 -- We can fold 'Alignment applied to a type if the alignment is known
5415 -- (as happens for an alignment from an attribute definition clause).
5416 -- At this stage, this can happen only for types (e.g. record
5417 -- types) for which the size is always non-static. We exclude
5418 -- generic types from consideration (since they have bogus
5419 -- sizes set within templates).
5421 elsif Id = Attribute_Alignment
5422 and then Is_Type (P_Entity)
5423 and then (not Is_Generic_Type (P_Entity))
5424 and then Known_Alignment (P_Entity)
5426 Compile_Time_Known_Attribute (N, Alignment (P_Entity));
5429 -- If this is an access attribute that is known to fail accessibility
5430 -- check, rewrite accordingly.
5432 elsif Attribute_Name (N) = Name_Access
5433 and then Raises_Constraint_Error (N)
5436 Make_Raise_Program_Error (Loc,
5437 Reason => PE_Accessibility_Check_Failed));
5438 Set_Etype (N, C_Type);
5441 -- No other cases are foldable (they certainly aren't static, and at
5442 -- the moment we don't try to fold any cases other than these three).
5449 -- If either attribute or the prefix is Any_Type, then propagate
5450 -- Any_Type to the result and don't do anything else at all.
5452 if P_Type = Any_Type
5453 or else (Present (E1) and then Etype (E1) = Any_Type)
5454 or else (Present (E2) and then Etype (E2) = Any_Type)
5456 Set_Etype (N, Any_Type);
5460 -- Scalar subtype case. We have not yet enforced the static requirement
5461 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
5462 -- of non-static attribute references (e.g. S'Digits for a non-static
5463 -- floating-point type, which we can compute at compile time).
5465 -- Note: this folding of non-static attributes is not simply a case of
5466 -- optimization. For many of the attributes affected, Gigi cannot handle
5467 -- the attribute and depends on the front end having folded them away.
5469 -- Note: although we don't require staticness at this stage, we do set
5470 -- the Static variable to record the staticness, for easy reference by
5471 -- those attributes where it matters (e.g. Succ and Pred), and also to
5472 -- be used to ensure that non-static folded things are not marked as
5473 -- being static (a check that is done right at the end).
5475 P_Root_Type := Root_Type (P_Type);
5476 P_Base_Type := Base_Type (P_Type);
5478 -- If the root type or base type is generic, then we cannot fold. This
5479 -- test is needed because subtypes of generic types are not always
5480 -- marked as being generic themselves (which seems odd???)
5482 if Is_Generic_Type (P_Root_Type)
5483 or else Is_Generic_Type (P_Base_Type)
5488 if Is_Scalar_Type (P_Type) then
5489 Static := Is_OK_Static_Subtype (P_Type);
5491 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
5492 -- since we can't do anything with unconstrained arrays. In addition,
5493 -- only the First, Last and Length attributes are possibly static.
5495 -- Definite, Has_Access_Values, Has_Discriminants, Has_Tagged_Values,
5496 -- Type_Class, and Unconstrained_Array are again exceptions, because
5497 -- they apply as well to unconstrained types.
5499 -- In addition Component_Size is an exception since it is possibly
5500 -- foldable, even though it is never static, and it does apply to
5501 -- unconstrained arrays. Furthermore, it is essential to fold this
5502 -- in the packed case, since otherwise the value will be incorrect.
5504 elsif Id = Attribute_Definite
5506 Id = Attribute_Has_Access_Values
5508 Id = Attribute_Has_Discriminants
5510 Id = Attribute_Has_Tagged_Values
5512 Id = Attribute_Type_Class
5514 Id = Attribute_Unconstrained_Array
5516 Id = Attribute_Component_Size
5521 if not Is_Constrained (P_Type)
5522 or else (Id /= Attribute_First and then
5523 Id /= Attribute_Last and then
5524 Id /= Attribute_Length)
5530 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
5531 -- scalar case, we hold off on enforcing staticness, since there are
5532 -- cases which we can fold at compile time even though they are not
5533 -- static (e.g. 'Length applied to a static index, even though other
5534 -- non-static indexes make the array type non-static). This is only
5535 -- an optimization, but it falls out essentially free, so why not.
5536 -- Again we compute the variable Static for easy reference later
5537 -- (note that no array attributes are static in Ada 83).
5539 -- We also need to set Static properly for subsequent legality checks
5540 -- which might otherwise accept non-static constants in contexts
5541 -- where they are not legal.
5543 Static := Ada_Version >= Ada_95
5544 and then Statically_Denotes_Entity (P);
5550 N := First_Index (P_Type);
5552 -- The expression is static if the array type is constrained
5553 -- by given bounds, and not by an initial expression. Constant
5554 -- strings are static in any case.
5556 if Root_Type (P_Type) /= Standard_String then
5558 Static and then not Is_Constr_Subt_For_U_Nominal (P_Type);
5561 while Present (N) loop
5562 Static := Static and then Is_Static_Subtype (Etype (N));
5564 -- If however the index type is generic, attributes cannot
5567 if Is_Generic_Type (Etype (N))
5568 and then Id /= Attribute_Component_Size
5578 -- Check any expressions that are present. Note that these expressions,
5579 -- depending on the particular attribute type, are either part of the
5580 -- attribute designator, or they are arguments in a case where the
5581 -- attribute reference returns a function. In the latter case, the
5582 -- rule in (RM 4.9(22)) applies and in particular requires the type
5583 -- of the expressions to be scalar in order for the attribute to be
5584 -- considered to be static.
5591 while Present (E) loop
5593 -- If expression is not static, then the attribute reference
5594 -- result certainly cannot be static.
5596 if not Is_Static_Expression (E) then
5600 -- If the result is not known at compile time, or is not of
5601 -- a scalar type, then the result is definitely not static,
5602 -- so we can quit now.
5604 if not Compile_Time_Known_Value (E)
5605 or else not Is_Scalar_Type (Etype (E))
5607 -- An odd special case, if this is a Pos attribute, this
5608 -- is where we need to apply a range check since it does
5609 -- not get done anywhere else.
5611 if Id = Attribute_Pos then
5612 if Is_Integer_Type (Etype (E)) then
5613 Apply_Range_Check (E, Etype (N));
5620 -- If the expression raises a constraint error, then so does
5621 -- the attribute reference. We keep going in this case because
5622 -- we are still interested in whether the attribute reference
5623 -- is static even if it is not static.
5625 elsif Raises_Constraint_Error (E) then
5626 Set_Raises_Constraint_Error (N);
5632 if Raises_Constraint_Error (Prefix (N)) then
5637 -- Deal with the case of a static attribute reference that raises
5638 -- constraint error. The Raises_Constraint_Error flag will already
5639 -- have been set, and the Static flag shows whether the attribute
5640 -- reference is static. In any case we certainly can't fold such an
5641 -- attribute reference.
5643 -- Note that the rewriting of the attribute node with the constraint
5644 -- error node is essential in this case, because otherwise Gigi might
5645 -- blow up on one of the attributes it never expects to see.
5647 -- The constraint_error node must have the type imposed by the context,
5648 -- to avoid spurious errors in the enclosing expression.
5650 if Raises_Constraint_Error (N) then
5652 Make_Raise_Constraint_Error (Sloc (N),
5653 Reason => CE_Range_Check_Failed);
5654 Set_Etype (CE_Node, Etype (N));
5655 Set_Raises_Constraint_Error (CE_Node);
5657 Rewrite (N, Relocate_Node (CE_Node));
5658 Set_Is_Static_Expression (N, Static);
5662 -- At this point we have a potentially foldable attribute reference.
5663 -- If Static is set, then the attribute reference definitely obeys
5664 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
5665 -- folded. If Static is not set, then the attribute may or may not
5666 -- be foldable, and the individual attribute processing routines
5667 -- test Static as required in cases where it makes a difference.
5669 -- In the case where Static is not set, we do know that all the
5670 -- expressions present are at least known at compile time (we
5671 -- assumed above that if this was not the case, then there was
5672 -- no hope of static evaluation). However, we did not require
5673 -- that the bounds of the prefix type be compile time known,
5674 -- let alone static). That's because there are many attributes
5675 -- that can be computed at compile time on non-static subtypes,
5676 -- even though such references are not static expressions.
5684 when Attribute_Adjacent =>
5687 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5693 when Attribute_Aft =>
5694 Fold_Uint (N, UI_From_Int (Aft_Value), True);
5700 when Attribute_Alignment => Alignment_Block : declare
5701 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5704 -- Fold if alignment is set and not otherwise
5706 if Known_Alignment (P_TypeA) then
5707 Fold_Uint (N, Alignment (P_TypeA), Is_Discrete_Type (P_TypeA));
5709 end Alignment_Block;
5715 -- Can only be folded in No_Ast_Handler case
5717 when Attribute_AST_Entry =>
5718 if not Is_AST_Entry (P_Entity) then
5720 New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc));
5729 -- Bit can never be folded
5731 when Attribute_Bit =>
5738 -- Body_version can never be static
5740 when Attribute_Body_Version =>
5747 when Attribute_Ceiling =>
5749 Eval_Fat.Ceiling (P_Root_Type, Expr_Value_R (E1)), Static);
5751 --------------------
5752 -- Component_Size --
5753 --------------------
5755 when Attribute_Component_Size =>
5756 if Known_Static_Component_Size (P_Type) then
5757 Fold_Uint (N, Component_Size (P_Type), False);
5764 when Attribute_Compose =>
5767 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)),
5774 -- Constrained is never folded for now, there may be cases that
5775 -- could be handled at compile time. To be looked at later.
5777 when Attribute_Constrained =>
5784 when Attribute_Copy_Sign =>
5787 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5793 when Attribute_Delta =>
5794 Fold_Ureal (N, Delta_Value (P_Type), True);
5800 when Attribute_Definite =>
5801 Rewrite (N, New_Occurrence_Of (
5802 Boolean_Literals (not Is_Indefinite_Subtype (P_Entity)), Loc));
5803 Analyze_And_Resolve (N, Standard_Boolean);
5809 when Attribute_Denorm =>
5811 (N, UI_From_Int (Boolean'Pos (Denorm_On_Target)), True);
5817 when Attribute_Digits =>
5818 Fold_Uint (N, Digits_Value (P_Type), True);
5824 when Attribute_Emax =>
5826 -- Ada 83 attribute is defined as (RM83 3.5.8)
5828 -- T'Emax = 4 * T'Mantissa
5830 Fold_Uint (N, 4 * Mantissa, True);
5836 when Attribute_Enum_Rep =>
5838 -- For an enumeration type with a non-standard representation use
5839 -- the Enumeration_Rep field of the proper constant. Note that this
5840 -- will not work for types Character/Wide_[Wide-]Character, since no
5841 -- real entities are created for the enumeration literals, but that
5842 -- does not matter since these two types do not have non-standard
5843 -- representations anyway.
5845 if Is_Enumeration_Type (P_Type)
5846 and then Has_Non_Standard_Rep (P_Type)
5848 Fold_Uint (N, Enumeration_Rep (Expr_Value_E (E1)), Static);
5850 -- For enumeration types with standard representations and all
5851 -- other cases (i.e. all integer and modular types), Enum_Rep
5852 -- is equivalent to Pos.
5855 Fold_Uint (N, Expr_Value (E1), Static);
5862 when Attribute_Enum_Val => Enum_Val : declare
5866 -- We have something like Enum_Type'Enum_Val (23), so search for a
5867 -- corresponding value in the list of Enum_Rep values for the type.
5869 Lit := First_Literal (P_Base_Type);
5871 if Enumeration_Rep (Lit) = Expr_Value (E1) then
5872 Fold_Uint (N, Enumeration_Pos (Lit), Static);
5879 Apply_Compile_Time_Constraint_Error
5880 (N, "no representation value matches",
5881 CE_Range_Check_Failed,
5882 Warn => not Static);
5892 when Attribute_Epsilon =>
5894 -- Ada 83 attribute is defined as (RM83 3.5.8)
5896 -- T'Epsilon = 2.0**(1 - T'Mantissa)
5898 Fold_Ureal (N, Ureal_2 ** (1 - Mantissa), True);
5904 when Attribute_Exponent =>
5906 Eval_Fat.Exponent (P_Root_Type, Expr_Value_R (E1)), Static);
5912 when Attribute_First => First_Attr :
5916 if Compile_Time_Known_Value (Lo_Bound) then
5917 if Is_Real_Type (P_Type) then
5918 Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static);
5920 Fold_Uint (N, Expr_Value (Lo_Bound), Static);
5929 when Attribute_Fixed_Value =>
5936 when Attribute_Floor =>
5938 Eval_Fat.Floor (P_Root_Type, Expr_Value_R (E1)), Static);
5944 when Attribute_Fore =>
5945 if Compile_Time_Known_Bounds (P_Type) then
5946 Fold_Uint (N, UI_From_Int (Fore_Value), Static);
5953 when Attribute_Fraction =>
5955 Eval_Fat.Fraction (P_Root_Type, Expr_Value_R (E1)), Static);
5957 -----------------------
5958 -- Has_Access_Values --
5959 -----------------------
5961 when Attribute_Has_Access_Values =>
5962 Rewrite (N, New_Occurrence_Of
5963 (Boolean_Literals (Has_Access_Values (P_Root_Type)), Loc));
5964 Analyze_And_Resolve (N, Standard_Boolean);
5966 -----------------------
5967 -- Has_Discriminants --
5968 -----------------------
5970 when Attribute_Has_Discriminants =>
5971 Rewrite (N, New_Occurrence_Of (
5972 Boolean_Literals (Has_Discriminants (P_Entity)), Loc));
5973 Analyze_And_Resolve (N, Standard_Boolean);
5975 -----------------------
5976 -- Has_Tagged_Values --
5977 -----------------------
5979 when Attribute_Has_Tagged_Values =>
5980 Rewrite (N, New_Occurrence_Of
5981 (Boolean_Literals (Has_Tagged_Component (P_Root_Type)), Loc));
5982 Analyze_And_Resolve (N, Standard_Boolean);
5988 when Attribute_Identity =>
5995 -- Image is a scalar attribute, but is never static, because it is
5996 -- not a static function (having a non-scalar argument (RM 4.9(22))
5997 -- However, we can constant-fold the image of an enumeration literal
5998 -- if names are available.
6000 when Attribute_Image =>
6001 if Is_Entity_Name (E1)
6002 and then Ekind (Entity (E1)) = E_Enumeration_Literal
6003 and then not Discard_Names (First_Subtype (Etype (E1)))
6004 and then not Global_Discard_Names
6007 Lit : constant Entity_Id := Entity (E1);
6011 Get_Unqualified_Decoded_Name_String (Chars (Lit));
6012 Set_Casing (All_Upper_Case);
6013 Store_String_Chars (Name_Buffer (1 .. Name_Len));
6015 Rewrite (N, Make_String_Literal (Loc, Strval => Str));
6016 Analyze_And_Resolve (N, Standard_String);
6017 Set_Is_Static_Expression (N, False);
6025 -- Img is a scalar attribute, but is never static, because it is
6026 -- not a static function (having a non-scalar argument (RM 4.9(22))
6028 when Attribute_Img =>
6035 -- We never try to fold Integer_Value (though perhaps we could???)
6037 when Attribute_Integer_Value =>
6044 -- Invalid_Value is a scalar attribute that is never static, because
6045 -- the value is by design out of range.
6047 when Attribute_Invalid_Value =>
6054 when Attribute_Large =>
6056 -- For fixed-point, we use the identity:
6058 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
6060 if Is_Fixed_Point_Type (P_Type) then
6062 Make_Op_Multiply (Loc,
6064 Make_Op_Subtract (Loc,
6068 Make_Real_Literal (Loc, Ureal_2),
6070 Make_Attribute_Reference (Loc,
6072 Attribute_Name => Name_Mantissa)),
6073 Right_Opnd => Make_Real_Literal (Loc, Ureal_1)),
6076 Make_Real_Literal (Loc, Small_Value (Entity (P)))));
6078 Analyze_And_Resolve (N, C_Type);
6080 -- Floating-point (Ada 83 compatibility)
6083 -- Ada 83 attribute is defined as (RM83 3.5.8)
6085 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
6089 -- T'Emax = 4 * T'Mantissa
6092 Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)),
6100 when Attribute_Last => Last :
6104 if Compile_Time_Known_Value (Hi_Bound) then
6105 if Is_Real_Type (P_Type) then
6106 Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static);
6108 Fold_Uint (N, Expr_Value (Hi_Bound), Static);
6117 when Attribute_Leading_Part =>
6119 Eval_Fat.Leading_Part
6120 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
6126 when Attribute_Length => Length : declare
6130 -- In the case of a generic index type, the bounds may
6131 -- appear static but the computation is not meaningful,
6132 -- and may generate a spurious warning.
6134 Ind := First_Index (P_Type);
6136 while Present (Ind) loop
6137 if Is_Generic_Type (Etype (Ind)) then
6146 if Compile_Time_Known_Value (Lo_Bound)
6147 and then Compile_Time_Known_Value (Hi_Bound)
6150 UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))),
6159 when Attribute_Machine =>
6162 (P_Root_Type, Expr_Value_R (E1), Eval_Fat.Round, N),
6169 when Attribute_Machine_Emax =>
6170 Float_Attribute_Universal_Integer (
6178 AAMPL_Machine_Emax);
6184 when Attribute_Machine_Emin =>
6185 Float_Attribute_Universal_Integer (
6193 AAMPL_Machine_Emin);
6195 ----------------------
6196 -- Machine_Mantissa --
6197 ----------------------
6199 when Attribute_Machine_Mantissa =>
6200 Float_Attribute_Universal_Integer (
6201 IEEES_Machine_Mantissa,
6202 IEEEL_Machine_Mantissa,
6203 IEEEX_Machine_Mantissa,
6204 VAXFF_Machine_Mantissa,
6205 VAXDF_Machine_Mantissa,
6206 VAXGF_Machine_Mantissa,
6207 AAMPS_Machine_Mantissa,
6208 AAMPL_Machine_Mantissa);
6210 -----------------------
6211 -- Machine_Overflows --
6212 -----------------------
6214 when Attribute_Machine_Overflows =>
6216 -- Always true for fixed-point
6218 if Is_Fixed_Point_Type (P_Type) then
6219 Fold_Uint (N, True_Value, True);
6221 -- Floating point case
6225 UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
6233 when Attribute_Machine_Radix =>
6234 if Is_Fixed_Point_Type (P_Type) then
6235 if Is_Decimal_Fixed_Point_Type (P_Type)
6236 and then Machine_Radix_10 (P_Type)
6238 Fold_Uint (N, Uint_10, True);
6240 Fold_Uint (N, Uint_2, True);
6243 -- All floating-point type always have radix 2
6246 Fold_Uint (N, Uint_2, True);
6249 ----------------------
6250 -- Machine_Rounding --
6251 ----------------------
6253 -- Note: for the folding case, it is fine to treat Machine_Rounding
6254 -- exactly the same way as Rounding, since this is one of the allowed
6255 -- behaviors, and performance is not an issue here. It might be a bit
6256 -- better to give the same result as it would give at run-time, even
6257 -- though the non-determinism is certainly permitted.
6259 when Attribute_Machine_Rounding =>
6261 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
6263 --------------------
6264 -- Machine_Rounds --
6265 --------------------
6267 when Attribute_Machine_Rounds =>
6269 -- Always False for fixed-point
6271 if Is_Fixed_Point_Type (P_Type) then
6272 Fold_Uint (N, False_Value, True);
6274 -- Else yield proper floating-point result
6278 (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), True);
6285 -- Note: Machine_Size is identical to Object_Size
6287 when Attribute_Machine_Size => Machine_Size : declare
6288 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6291 if Known_Esize (P_TypeA) then
6292 Fold_Uint (N, Esize (P_TypeA), True);
6300 when Attribute_Mantissa =>
6302 -- Fixed-point mantissa
6304 if Is_Fixed_Point_Type (P_Type) then
6306 -- Compile time foldable case
6308 if Compile_Time_Known_Value (Type_Low_Bound (P_Type))
6310 Compile_Time_Known_Value (Type_High_Bound (P_Type))
6312 -- The calculation of the obsolete Ada 83 attribute Mantissa
6313 -- is annoying, because of AI00143, quoted here:
6315 -- !question 84-01-10
6317 -- Consider the model numbers for F:
6319 -- type F is delta 1.0 range -7.0 .. 8.0;
6321 -- The wording requires that F'MANTISSA be the SMALLEST
6322 -- integer number for which each bound of the specified
6323 -- range is either a model number or lies at most small
6324 -- distant from a model number. This means F'MANTISSA
6325 -- is required to be 3 since the range -7.0 .. 7.0 fits
6326 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
6327 -- number, namely, 7. Is this analysis correct? Note that
6328 -- this implies the upper bound of the range is not
6329 -- represented as a model number.
6331 -- !response 84-03-17
6333 -- The analysis is correct. The upper and lower bounds for
6334 -- a fixed point type can lie outside the range of model
6345 LBound := Expr_Value_R (Type_Low_Bound (P_Type));
6346 UBound := Expr_Value_R (Type_High_Bound (P_Type));
6347 Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound));
6348 Max_Man := UR_Trunc (Bound / Small_Value (P_Type));
6350 -- If the Bound is exactly a model number, i.e. a multiple
6351 -- of Small, then we back it off by one to get the integer
6352 -- value that must be representable.
6354 if Small_Value (P_Type) * Max_Man = Bound then
6355 Max_Man := Max_Man - 1;
6358 -- Now find corresponding size = Mantissa value
6361 while 2 ** Siz < Max_Man loop
6365 Fold_Uint (N, Siz, True);
6369 -- The case of dynamic bounds cannot be evaluated at compile
6370 -- time. Instead we use a runtime routine (see Exp_Attr).
6375 -- Floating-point Mantissa
6378 Fold_Uint (N, Mantissa, True);
6385 when Attribute_Max => Max :
6387 if Is_Real_Type (P_Type) then
6389 (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6391 Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
6395 ----------------------------------
6396 -- Max_Size_In_Storage_Elements --
6397 ----------------------------------
6399 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
6400 -- Storage_Unit boundary. We can fold any cases for which the size
6401 -- is known by the front end.
6403 when Attribute_Max_Size_In_Storage_Elements =>
6404 if Known_Esize (P_Type) then
6406 (Esize (P_Type) + System_Storage_Unit - 1) /
6407 System_Storage_Unit,
6411 --------------------
6412 -- Mechanism_Code --
6413 --------------------
6415 when Attribute_Mechanism_Code =>
6419 Mech : Mechanism_Type;
6423 Mech := Mechanism (P_Entity);
6426 Val := UI_To_Int (Expr_Value (E1));
6428 Formal := First_Formal (P_Entity);
6429 for J in 1 .. Val - 1 loop
6430 Next_Formal (Formal);
6432 Mech := Mechanism (Formal);
6436 Fold_Uint (N, UI_From_Int (Int (-Mech)), True);
6444 when Attribute_Min => Min :
6446 if Is_Real_Type (P_Type) then
6448 (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
6451 (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
6459 when Attribute_Mod =>
6461 (N, UI_Mod (Expr_Value (E1), Modulus (P_Base_Type)), Static);
6467 when Attribute_Model =>
6469 Eval_Fat.Model (P_Root_Type, Expr_Value_R (E1)), Static);
6475 when Attribute_Model_Emin =>
6476 Float_Attribute_Universal_Integer (
6490 when Attribute_Model_Epsilon =>
6491 Float_Attribute_Universal_Real (
6492 IEEES_Model_Epsilon'Universal_Literal_String,
6493 IEEEL_Model_Epsilon'Universal_Literal_String,
6494 IEEEX_Model_Epsilon'Universal_Literal_String,
6495 VAXFF_Model_Epsilon'Universal_Literal_String,
6496 VAXDF_Model_Epsilon'Universal_Literal_String,
6497 VAXGF_Model_Epsilon'Universal_Literal_String,
6498 AAMPS_Model_Epsilon'Universal_Literal_String,
6499 AAMPL_Model_Epsilon'Universal_Literal_String);
6501 --------------------
6502 -- Model_Mantissa --
6503 --------------------
6505 when Attribute_Model_Mantissa =>
6506 Float_Attribute_Universal_Integer (
6507 IEEES_Model_Mantissa,
6508 IEEEL_Model_Mantissa,
6509 IEEEX_Model_Mantissa,
6510 VAXFF_Model_Mantissa,
6511 VAXDF_Model_Mantissa,
6512 VAXGF_Model_Mantissa,
6513 AAMPS_Model_Mantissa,
6514 AAMPL_Model_Mantissa);
6520 when Attribute_Model_Small =>
6521 Float_Attribute_Universal_Real (
6522 IEEES_Model_Small'Universal_Literal_String,
6523 IEEEL_Model_Small'Universal_Literal_String,
6524 IEEEX_Model_Small'Universal_Literal_String,
6525 VAXFF_Model_Small'Universal_Literal_String,
6526 VAXDF_Model_Small'Universal_Literal_String,
6527 VAXGF_Model_Small'Universal_Literal_String,
6528 AAMPS_Model_Small'Universal_Literal_String,
6529 AAMPL_Model_Small'Universal_Literal_String);
6535 when Attribute_Modulus =>
6536 Fold_Uint (N, Modulus (P_Type), True);
6538 --------------------
6539 -- Null_Parameter --
6540 --------------------
6542 -- Cannot fold, we know the value sort of, but the whole point is
6543 -- that there is no way to talk about this imaginary value except
6544 -- by using the attribute, so we leave it the way it is.
6546 when Attribute_Null_Parameter =>
6553 -- The Object_Size attribute for a type returns the Esize of the
6554 -- type and can be folded if this value is known.
6556 when Attribute_Object_Size => Object_Size : declare
6557 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6560 if Known_Esize (P_TypeA) then
6561 Fold_Uint (N, Esize (P_TypeA), True);
6565 -------------------------
6566 -- Passed_By_Reference --
6567 -------------------------
6569 -- Scalar types are never passed by reference
6571 when Attribute_Passed_By_Reference =>
6572 Fold_Uint (N, False_Value, True);
6578 when Attribute_Pos =>
6579 Fold_Uint (N, Expr_Value (E1), True);
6585 when Attribute_Pred => Pred :
6587 -- Floating-point case
6589 if Is_Floating_Point_Type (P_Type) then
6591 Eval_Fat.Pred (P_Root_Type, Expr_Value_R (E1)), Static);
6595 elsif Is_Fixed_Point_Type (P_Type) then
6597 Expr_Value_R (E1) - Small_Value (P_Type), True);
6599 -- Modular integer case (wraps)
6601 elsif Is_Modular_Integer_Type (P_Type) then
6602 Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static);
6604 -- Other scalar cases
6607 pragma Assert (Is_Scalar_Type (P_Type));
6609 if Is_Enumeration_Type (P_Type)
6610 and then Expr_Value (E1) =
6611 Expr_Value (Type_Low_Bound (P_Base_Type))
6613 Apply_Compile_Time_Constraint_Error
6614 (N, "Pred of `&''First`",
6615 CE_Overflow_Check_Failed,
6617 Warn => not Static);
6623 Fold_Uint (N, Expr_Value (E1) - 1, Static);
6631 -- No processing required, because by this stage, Range has been
6632 -- replaced by First .. Last, so this branch can never be taken.
6634 when Attribute_Range =>
6635 raise Program_Error;
6641 when Attribute_Range_Length =>
6644 if Compile_Time_Known_Value (Hi_Bound)
6645 and then Compile_Time_Known_Value (Lo_Bound)
6649 (0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1),
6657 when Attribute_Remainder => Remainder : declare
6658 X : constant Ureal := Expr_Value_R (E1);
6659 Y : constant Ureal := Expr_Value_R (E2);
6662 if UR_Is_Zero (Y) then
6663 Apply_Compile_Time_Constraint_Error
6664 (N, "division by zero in Remainder",
6665 CE_Overflow_Check_Failed,
6666 Warn => not Static);
6672 Fold_Ureal (N, Eval_Fat.Remainder (P_Root_Type, X, Y), Static);
6679 when Attribute_Round => Round :
6685 -- First we get the (exact result) in units of small
6687 Sr := Expr_Value_R (E1) / Small_Value (C_Type);
6689 -- Now round that exactly to an integer
6691 Si := UR_To_Uint (Sr);
6693 -- Finally the result is obtained by converting back to real
6695 Fold_Ureal (N, Si * Small_Value (C_Type), Static);
6702 when Attribute_Rounding =>
6704 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
6710 when Attribute_Safe_Emax =>
6711 Float_Attribute_Universal_Integer (
6725 when Attribute_Safe_First =>
6726 Float_Attribute_Universal_Real (
6727 IEEES_Safe_First'Universal_Literal_String,
6728 IEEEL_Safe_First'Universal_Literal_String,
6729 IEEEX_Safe_First'Universal_Literal_String,
6730 VAXFF_Safe_First'Universal_Literal_String,
6731 VAXDF_Safe_First'Universal_Literal_String,
6732 VAXGF_Safe_First'Universal_Literal_String,
6733 AAMPS_Safe_First'Universal_Literal_String,
6734 AAMPL_Safe_First'Universal_Literal_String);
6740 when Attribute_Safe_Large =>
6741 if Is_Fixed_Point_Type (P_Type) then
6743 (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static);
6745 Float_Attribute_Universal_Real (
6746 IEEES_Safe_Large'Universal_Literal_String,
6747 IEEEL_Safe_Large'Universal_Literal_String,
6748 IEEEX_Safe_Large'Universal_Literal_String,
6749 VAXFF_Safe_Large'Universal_Literal_String,
6750 VAXDF_Safe_Large'Universal_Literal_String,
6751 VAXGF_Safe_Large'Universal_Literal_String,
6752 AAMPS_Safe_Large'Universal_Literal_String,
6753 AAMPL_Safe_Large'Universal_Literal_String);
6760 when Attribute_Safe_Last =>
6761 Float_Attribute_Universal_Real (
6762 IEEES_Safe_Last'Universal_Literal_String,
6763 IEEEL_Safe_Last'Universal_Literal_String,
6764 IEEEX_Safe_Last'Universal_Literal_String,
6765 VAXFF_Safe_Last'Universal_Literal_String,
6766 VAXDF_Safe_Last'Universal_Literal_String,
6767 VAXGF_Safe_Last'Universal_Literal_String,
6768 AAMPS_Safe_Last'Universal_Literal_String,
6769 AAMPL_Safe_Last'Universal_Literal_String);
6775 when Attribute_Safe_Small =>
6777 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
6778 -- for fixed-point, since is the same as Small, but we implement
6779 -- it for backwards compatibility.
6781 if Is_Fixed_Point_Type (P_Type) then
6782 Fold_Ureal (N, Small_Value (P_Type), Static);
6784 -- Ada 83 Safe_Small for floating-point cases
6787 Float_Attribute_Universal_Real (
6788 IEEES_Safe_Small'Universal_Literal_String,
6789 IEEEL_Safe_Small'Universal_Literal_String,
6790 IEEEX_Safe_Small'Universal_Literal_String,
6791 VAXFF_Safe_Small'Universal_Literal_String,
6792 VAXDF_Safe_Small'Universal_Literal_String,
6793 VAXGF_Safe_Small'Universal_Literal_String,
6794 AAMPS_Safe_Small'Universal_Literal_String,
6795 AAMPL_Safe_Small'Universal_Literal_String);
6802 when Attribute_Scale =>
6803 Fold_Uint (N, Scale_Value (P_Type), True);
6809 when Attribute_Scaling =>
6812 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
6818 when Attribute_Signed_Zeros =>
6820 (N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)), Static);
6826 -- Size attribute returns the RM size. All scalar types can be folded,
6827 -- as well as any types for which the size is known by the front end,
6828 -- including any type for which a size attribute is specified.
6830 when Attribute_Size | Attribute_VADS_Size => Size : declare
6831 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
6834 if RM_Size (P_TypeA) /= Uint_0 then
6838 if Id = Attribute_VADS_Size or else Use_VADS_Size then
6840 S : constant Node_Id := Size_Clause (P_TypeA);
6843 -- If a size clause applies, then use the size from it.
6844 -- This is one of the rare cases where we can use the
6845 -- Size_Clause field for a subtype when Has_Size_Clause
6846 -- is False. Consider:
6848 -- type x is range 1 .. 64;
6849 -- for x'size use 12;
6850 -- subtype y is x range 0 .. 3;
6852 -- Here y has a size clause inherited from x, but normally
6853 -- it does not apply, and y'size is 2. However, y'VADS_Size
6854 -- is indeed 12 and not 2.
6857 and then Is_OK_Static_Expression (Expression (S))
6859 Fold_Uint (N, Expr_Value (Expression (S)), True);
6861 -- If no size is specified, then we simply use the object
6862 -- size in the VADS_Size case (e.g. Natural'Size is equal
6863 -- to Integer'Size, not one less).
6866 Fold_Uint (N, Esize (P_TypeA), True);
6870 -- Normal case (Size) in which case we want the RM_Size
6875 Static and then Is_Discrete_Type (P_TypeA));
6884 when Attribute_Small =>
6886 -- The floating-point case is present only for Ada 83 compatibility.
6887 -- Note that strictly this is an illegal addition, since we are
6888 -- extending an Ada 95 defined attribute, but we anticipate an
6889 -- ARG ruling that will permit this.
6891 if Is_Floating_Point_Type (P_Type) then
6893 -- Ada 83 attribute is defined as (RM83 3.5.8)
6895 -- T'Small = 2.0**(-T'Emax - 1)
6899 -- T'Emax = 4 * T'Mantissa
6901 Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), Static);
6903 -- Normal Ada 95 fixed-point case
6906 Fold_Ureal (N, Small_Value (P_Type), True);
6913 when Attribute_Stream_Size =>
6920 when Attribute_Succ => Succ :
6922 -- Floating-point case
6924 if Is_Floating_Point_Type (P_Type) then
6926 Eval_Fat.Succ (P_Root_Type, Expr_Value_R (E1)), Static);
6930 elsif Is_Fixed_Point_Type (P_Type) then
6932 Expr_Value_R (E1) + Small_Value (P_Type), Static);
6934 -- Modular integer case (wraps)
6936 elsif Is_Modular_Integer_Type (P_Type) then
6937 Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static);
6939 -- Other scalar cases
6942 pragma Assert (Is_Scalar_Type (P_Type));
6944 if Is_Enumeration_Type (P_Type)
6945 and then Expr_Value (E1) =
6946 Expr_Value (Type_High_Bound (P_Base_Type))
6948 Apply_Compile_Time_Constraint_Error
6949 (N, "Succ of `&''Last`",
6950 CE_Overflow_Check_Failed,
6952 Warn => not Static);
6957 Fold_Uint (N, Expr_Value (E1) + 1, Static);
6966 when Attribute_Truncation =>
6968 Eval_Fat.Truncation (P_Root_Type, Expr_Value_R (E1)), Static);
6974 when Attribute_Type_Class => Type_Class : declare
6975 Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
6979 if Is_Descendent_Of_Address (Typ) then
6980 Id := RE_Type_Class_Address;
6982 elsif Is_Enumeration_Type (Typ) then
6983 Id := RE_Type_Class_Enumeration;
6985 elsif Is_Integer_Type (Typ) then
6986 Id := RE_Type_Class_Integer;
6988 elsif Is_Fixed_Point_Type (Typ) then
6989 Id := RE_Type_Class_Fixed_Point;
6991 elsif Is_Floating_Point_Type (Typ) then
6992 Id := RE_Type_Class_Floating_Point;
6994 elsif Is_Array_Type (Typ) then
6995 Id := RE_Type_Class_Array;
6997 elsif Is_Record_Type (Typ) then
6998 Id := RE_Type_Class_Record;
7000 elsif Is_Access_Type (Typ) then
7001 Id := RE_Type_Class_Access;
7003 elsif Is_Enumeration_Type (Typ) then
7004 Id := RE_Type_Class_Enumeration;
7006 elsif Is_Task_Type (Typ) then
7007 Id := RE_Type_Class_Task;
7009 -- We treat protected types like task types. It would make more
7010 -- sense to have another enumeration value, but after all the
7011 -- whole point of this feature is to be exactly DEC compatible,
7012 -- and changing the type Type_Class would not meet this requirement.
7014 elsif Is_Protected_Type (Typ) then
7015 Id := RE_Type_Class_Task;
7017 -- Not clear if there are any other possibilities, but if there
7018 -- are, then we will treat them as the address case.
7021 Id := RE_Type_Class_Address;
7024 Rewrite (N, New_Occurrence_Of (RTE (Id), Loc));
7027 -----------------------
7028 -- Unbiased_Rounding --
7029 -----------------------
7031 when Attribute_Unbiased_Rounding =>
7033 Eval_Fat.Unbiased_Rounding (P_Root_Type, Expr_Value_R (E1)),
7036 -------------------------
7037 -- Unconstrained_Array --
7038 -------------------------
7040 when Attribute_Unconstrained_Array => Unconstrained_Array : declare
7041 Typ : constant Entity_Id := Underlying_Type (P_Type);
7044 Rewrite (N, New_Occurrence_Of (
7046 Is_Array_Type (P_Type)
7047 and then not Is_Constrained (Typ)), Loc));
7049 -- Analyze and resolve as boolean, note that this attribute is
7050 -- a static attribute in GNAT.
7052 Analyze_And_Resolve (N, Standard_Boolean);
7054 end Unconstrained_Array;
7060 -- Processing is shared with Size
7066 when Attribute_Val => Val :
7068 if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type))
7070 Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type))
7072 Apply_Compile_Time_Constraint_Error
7073 (N, "Val expression out of range",
7074 CE_Range_Check_Failed,
7075 Warn => not Static);
7081 Fold_Uint (N, Expr_Value (E1), Static);
7089 -- The Value_Size attribute for a type returns the RM size of the
7090 -- type. This an always be folded for scalar types, and can also
7091 -- be folded for non-scalar types if the size is set.
7093 when Attribute_Value_Size => Value_Size : declare
7094 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
7096 if RM_Size (P_TypeA) /= Uint_0 then
7097 Fold_Uint (N, RM_Size (P_TypeA), True);
7105 -- Version can never be static
7107 when Attribute_Version =>
7114 -- Wide_Image is a scalar attribute, but is never static, because it
7115 -- is not a static function (having a non-scalar argument (RM 4.9(22))
7117 when Attribute_Wide_Image =>
7120 ---------------------
7121 -- Wide_Wide_Image --
7122 ---------------------
7124 -- Wide_Wide_Image is a scalar attribute but is never static, because it
7125 -- is not a static function (having a non-scalar argument (RM 4.9(22)).
7127 when Attribute_Wide_Wide_Image =>
7130 ---------------------
7131 -- Wide_Wide_Width --
7132 ---------------------
7134 -- Processing for Wide_Wide_Width is combined with Width
7140 -- Processing for Wide_Width is combined with Width
7146 -- This processing also handles the case of Wide_[Wide_]Width
7148 when Attribute_Width |
7149 Attribute_Wide_Width |
7150 Attribute_Wide_Wide_Width => Width :
7152 if Compile_Time_Known_Bounds (P_Type) then
7154 -- Floating-point types
7156 if Is_Floating_Point_Type (P_Type) then
7158 -- Width is zero for a null range (RM 3.5 (38))
7160 if Expr_Value_R (Type_High_Bound (P_Type)) <
7161 Expr_Value_R (Type_Low_Bound (P_Type))
7163 Fold_Uint (N, Uint_0, True);
7166 -- For floating-point, we have +N.dddE+nnn where length
7167 -- of ddd is determined by type'Digits - 1, but is one
7168 -- if Digits is one (RM 3.5 (33)).
7170 -- nnn is set to 2 for Short_Float and Float (32 bit
7171 -- floats), and 3 for Long_Float and Long_Long_Float.
7172 -- For machines where Long_Long_Float is the IEEE
7173 -- extended precision type, the exponent takes 4 digits.
7177 Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
7180 if Esize (P_Type) <= 32 then
7182 elsif Esize (P_Type) = 64 then
7188 Fold_Uint (N, UI_From_Int (Len), True);
7192 -- Fixed-point types
7194 elsif Is_Fixed_Point_Type (P_Type) then
7196 -- Width is zero for a null range (RM 3.5 (38))
7198 if Expr_Value (Type_High_Bound (P_Type)) <
7199 Expr_Value (Type_Low_Bound (P_Type))
7201 Fold_Uint (N, Uint_0, True);
7203 -- The non-null case depends on the specific real type
7206 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
7209 (N, UI_From_Int (Fore_Value + 1 + Aft_Value), True);
7216 R : constant Entity_Id := Root_Type (P_Type);
7217 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
7218 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
7231 -- Width for types derived from Standard.Character
7232 -- and Standard.Wide_[Wide_]Character.
7234 elsif Is_Standard_Character_Type (P_Type) then
7237 -- Set W larger if needed
7239 for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
7241 -- All wide characters look like Hex_hhhhhhhh
7247 C := Character'Val (J);
7249 -- Test for all cases where Character'Image
7250 -- yields an image that is longer than three
7251 -- characters. First the cases of Reserved_xxx
7252 -- names (length = 12).
7255 when Reserved_128 | Reserved_129 |
7256 Reserved_132 | Reserved_153
7260 when BS | HT | LF | VT | FF | CR |
7261 SO | SI | EM | FS | GS | RS |
7262 US | RI | MW | ST | PM
7266 when NUL | SOH | STX | ETX | EOT |
7267 ENQ | ACK | BEL | DLE | DC1 |
7268 DC2 | DC3 | DC4 | NAK | SYN |
7269 ETB | CAN | SUB | ESC | DEL |
7270 BPH | NBH | NEL | SSA | ESA |
7271 HTS | HTJ | VTS | PLD | PLU |
7272 SS2 | SS3 | DCS | PU1 | PU2 |
7273 STS | CCH | SPA | EPA | SOS |
7274 SCI | CSI | OSC | APC
7278 when Space .. Tilde |
7279 No_Break_Space .. LC_Y_Diaeresis
7284 W := Int'Max (W, Wt);
7288 -- Width for types derived from Standard.Boolean
7290 elsif R = Standard_Boolean then
7297 -- Width for integer types
7299 elsif Is_Integer_Type (P_Type) then
7300 T := UI_Max (abs Lo, abs Hi);
7308 -- Only remaining possibility is user declared enum type
7311 pragma Assert (Is_Enumeration_Type (P_Type));
7314 L := First_Literal (P_Type);
7316 while Present (L) loop
7318 -- Only pay attention to in range characters
7320 if Lo <= Enumeration_Pos (L)
7321 and then Enumeration_Pos (L) <= Hi
7323 -- For Width case, use decoded name
7325 if Id = Attribute_Width then
7326 Get_Decoded_Name_String (Chars (L));
7327 Wt := Nat (Name_Len);
7329 -- For Wide_[Wide_]Width, use encoded name, and
7330 -- then adjust for the encoding.
7333 Get_Name_String (Chars (L));
7335 -- Character literals are always of length 3
7337 if Name_Buffer (1) = 'Q' then
7340 -- Otherwise loop to adjust for upper/wide chars
7343 Wt := Nat (Name_Len);
7345 for J in 1 .. Name_Len loop
7346 if Name_Buffer (J) = 'U' then
7348 elsif Name_Buffer (J) = 'W' then
7355 W := Int'Max (W, Wt);
7362 Fold_Uint (N, UI_From_Int (W), True);
7368 -- The following attributes denote function that cannot be folded
7370 when Attribute_From_Any |
7372 Attribute_TypeCode =>
7375 -- The following attributes can never be folded, and furthermore we
7376 -- should not even have entered the case statement for any of these.
7377 -- Note that in some cases, the values have already been folded as
7378 -- a result of the processing in Analyze_Attribute.
7380 when Attribute_Abort_Signal |
7383 Attribute_Address_Size |
7384 Attribute_Asm_Input |
7385 Attribute_Asm_Output |
7387 Attribute_Bit_Order |
7388 Attribute_Bit_Position |
7389 Attribute_Callable |
7392 Attribute_Code_Address |
7394 Attribute_Default_Bit_Order |
7395 Attribute_Elaborated |
7396 Attribute_Elab_Body |
7397 Attribute_Elab_Spec |
7399 Attribute_External_Tag |
7400 Attribute_Fast_Math |
7401 Attribute_First_Bit |
7403 Attribute_Last_Bit |
7404 Attribute_Maximum_Alignment |
7407 Attribute_Partition_ID |
7408 Attribute_Pool_Address |
7409 Attribute_Position |
7410 Attribute_Priority |
7413 Attribute_Storage_Pool |
7414 Attribute_Storage_Size |
7415 Attribute_Storage_Unit |
7416 Attribute_Stub_Type |
7418 Attribute_Target_Name |
7419 Attribute_Terminated |
7420 Attribute_To_Address |
7421 Attribute_UET_Address |
7422 Attribute_Unchecked_Access |
7423 Attribute_Universal_Literal_String |
7424 Attribute_Unrestricted_Access |
7427 Attribute_Wchar_T_Size |
7428 Attribute_Wide_Value |
7429 Attribute_Wide_Wide_Value |
7430 Attribute_Word_Size |
7433 raise Program_Error;
7436 -- At the end of the case, one more check. If we did a static evaluation
7437 -- so that the result is now a literal, then set Is_Static_Expression
7438 -- in the constant only if the prefix type is a static subtype. For
7439 -- non-static subtypes, the folding is still OK, but not static.
7441 -- An exception is the GNAT attribute Constrained_Array which is
7442 -- defined to be a static attribute in all cases.
7444 if Nkind_In (N, N_Integer_Literal,
7446 N_Character_Literal,
7448 or else (Is_Entity_Name (N)
7449 and then Ekind (Entity (N)) = E_Enumeration_Literal)
7451 Set_Is_Static_Expression (N, Static);
7453 -- If this is still an attribute reference, then it has not been folded
7454 -- and that means that its expressions are in a non-static context.
7456 elsif Nkind (N) = N_Attribute_Reference then
7459 -- Note: the else case not covered here are odd cases where the
7460 -- processing has transformed the attribute into something other
7461 -- than a constant. Nothing more to do in such cases.
7468 ------------------------------
7469 -- Is_Anonymous_Tagged_Base --
7470 ------------------------------
7472 function Is_Anonymous_Tagged_Base
7479 Anon = Current_Scope
7480 and then Is_Itype (Anon)
7481 and then Associated_Node_For_Itype (Anon) = Parent (Typ);
7482 end Is_Anonymous_Tagged_Base;
7484 --------------------------------
7485 -- Name_Implies_Lvalue_Prefix --
7486 --------------------------------
7488 function Name_Implies_Lvalue_Prefix (Nam : Name_Id) return Boolean is
7489 pragma Assert (Is_Attribute_Name (Nam));
7491 return Attribute_Name_Implies_Lvalue_Prefix (Get_Attribute_Id (Nam));
7492 end Name_Implies_Lvalue_Prefix;
7494 -----------------------
7495 -- Resolve_Attribute --
7496 -----------------------
7498 procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is
7499 Loc : constant Source_Ptr := Sloc (N);
7500 P : constant Node_Id := Prefix (N);
7501 Aname : constant Name_Id := Attribute_Name (N);
7502 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
7503 Btyp : constant Entity_Id := Base_Type (Typ);
7504 Des_Btyp : Entity_Id;
7505 Index : Interp_Index;
7507 Nom_Subt : Entity_Id;
7509 procedure Accessibility_Message;
7510 -- Error, or warning within an instance, if the static accessibility
7511 -- rules of 3.10.2 are violated.
7513 ---------------------------
7514 -- Accessibility_Message --
7515 ---------------------------
7517 procedure Accessibility_Message is
7518 Indic : Node_Id := Parent (Parent (N));
7521 -- In an instance, this is a runtime check, but one we
7522 -- know will fail, so generate an appropriate warning.
7524 if In_Instance_Body then
7526 ("?non-local pointer cannot point to local object", P);
7528 ("\?Program_Error will be raised at run time", P);
7530 Make_Raise_Program_Error (Loc,
7531 Reason => PE_Accessibility_Check_Failed));
7537 ("non-local pointer cannot point to local object", P);
7539 -- Check for case where we have a missing access definition
7541 if Is_Record_Type (Current_Scope)
7543 Nkind_In (Parent (N), N_Discriminant_Association,
7544 N_Index_Or_Discriminant_Constraint)
7546 Indic := Parent (Parent (N));
7547 while Present (Indic)
7548 and then Nkind (Indic) /= N_Subtype_Indication
7550 Indic := Parent (Indic);
7553 if Present (Indic) then
7555 ("\use an access definition for" &
7556 " the access discriminant of&",
7557 N, Entity (Subtype_Mark (Indic)));
7561 end Accessibility_Message;
7563 -- Start of processing for Resolve_Attribute
7566 -- If error during analysis, no point in continuing, except for
7567 -- array types, where we get better recovery by using unconstrained
7568 -- indices than nothing at all (see Check_Array_Type).
7571 and then Attr_Id /= Attribute_First
7572 and then Attr_Id /= Attribute_Last
7573 and then Attr_Id /= Attribute_Length
7574 and then Attr_Id /= Attribute_Range
7579 -- If attribute was universal type, reset to actual type
7581 if Etype (N) = Universal_Integer
7582 or else Etype (N) = Universal_Real
7587 -- Remaining processing depends on attribute
7595 -- For access attributes, if the prefix denotes an entity, it is
7596 -- interpreted as a name, never as a call. It may be overloaded,
7597 -- in which case resolution uses the profile of the context type.
7598 -- Otherwise prefix must be resolved.
7600 when Attribute_Access
7601 | Attribute_Unchecked_Access
7602 | Attribute_Unrestricted_Access =>
7606 if Is_Variable (P) then
7607 Note_Possible_Modification (P, Sure => False);
7610 -- The following comes from a query by Adam Beneschan, concerning
7611 -- improper use of universal_access in equality tests involving
7612 -- anonymous access types. Another good reason for 'Ref, but
7613 -- for now disable the test, which breaks several filed tests.
7615 if Ekind (Typ) = E_Anonymous_Access_Type
7616 and then Nkind_In (Parent (N), N_Op_Eq, N_Op_Ne)
7619 Error_Msg_N ("need unique type to resolve 'Access", N);
7620 Error_Msg_N ("\qualify attribute with some access type", N);
7623 if Is_Entity_Name (P) then
7624 if Is_Overloaded (P) then
7625 Get_First_Interp (P, Index, It);
7626 while Present (It.Nam) loop
7627 if Type_Conformant (Designated_Type (Typ), It.Nam) then
7628 Set_Entity (P, It.Nam);
7630 -- The prefix is definitely NOT overloaded anymore at
7631 -- this point, so we reset the Is_Overloaded flag to
7632 -- avoid any confusion when reanalyzing the node.
7634 Set_Is_Overloaded (P, False);
7635 Set_Is_Overloaded (N, False);
7636 Generate_Reference (Entity (P), P);
7640 Get_Next_Interp (Index, It);
7643 -- If Prefix is a subprogram name, it is frozen by this
7646 -- If it is a type, there is nothing to resolve.
7647 -- If it is an object, complete its resolution.
7649 elsif Is_Overloadable (Entity (P)) then
7651 -- Avoid insertion of freeze actions in spec expression mode
7653 if not In_Spec_Expression then
7654 Insert_Actions (N, Freeze_Entity (Entity (P), Loc));
7657 elsif Is_Type (Entity (P)) then
7663 Error_Msg_Name_1 := Aname;
7665 if not Is_Entity_Name (P) then
7668 elsif Is_Overloadable (Entity (P))
7669 and then Is_Abstract_Subprogram (Entity (P))
7671 Error_Msg_F ("prefix of % attribute cannot be abstract", P);
7672 Set_Etype (N, Any_Type);
7674 elsif Convention (Entity (P)) = Convention_Intrinsic then
7675 if Ekind (Entity (P)) = E_Enumeration_Literal then
7677 ("prefix of % attribute cannot be enumeration literal",
7681 ("prefix of % attribute cannot be intrinsic", P);
7684 Set_Etype (N, Any_Type);
7687 -- Assignments, return statements, components of aggregates,
7688 -- generic instantiations will require convention checks if
7689 -- the type is an access to subprogram. Given that there will
7690 -- also be accessibility checks on those, this is where the
7691 -- checks can eventually be centralized ???
7693 if Ekind (Btyp) = E_Access_Subprogram_Type
7695 Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
7697 Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type
7699 -- Deal with convention mismatch
7701 if Convention (Btyp) /= Convention (Entity (P)) then
7703 ("subprogram & has wrong convention", P, Entity (P));
7706 ("\does not match convention of access type &",
7709 if not Has_Convention_Pragma (Btyp) then
7711 ("\probable missing pragma Convention for &",
7716 Check_Subtype_Conformant
7717 (New_Id => Entity (P),
7718 Old_Id => Designated_Type (Btyp),
7722 if Attr_Id = Attribute_Unchecked_Access then
7723 Error_Msg_Name_1 := Aname;
7725 ("attribute% cannot be applied to a subprogram", P);
7727 elsif Aname = Name_Unrestricted_Access then
7728 null; -- Nothing to check
7730 -- Check the static accessibility rule of 3.10.2(32).
7731 -- This rule also applies within the private part of an
7732 -- instantiation. This rule does not apply to anonymous
7733 -- access-to-subprogram types (Ada 2005).
7735 elsif Attr_Id = Attribute_Access
7736 and then not In_Instance_Body
7737 and then Subprogram_Access_Level (Entity (P)) >
7738 Type_Access_Level (Btyp)
7739 and then Ekind (Btyp) /=
7740 E_Anonymous_Access_Subprogram_Type
7741 and then Ekind (Btyp) /=
7742 E_Anonymous_Access_Protected_Subprogram_Type
7745 ("subprogram must not be deeper than access type", P);
7747 -- Check the restriction of 3.10.2(32) that disallows the
7748 -- access attribute within a generic body when the ultimate
7749 -- ancestor of the type of the attribute is declared outside
7750 -- of the generic unit and the subprogram is declared within
7751 -- that generic unit. This includes any such attribute that
7752 -- occurs within the body of a generic unit that is a child
7753 -- of the generic unit where the subprogram is declared.
7754 -- The rule also prohibits applying the attribute when the
7755 -- access type is a generic formal access type (since the
7756 -- level of the actual type is not known). This restriction
7757 -- does not apply when the attribute type is an anonymous
7758 -- access-to-subprogram type. Note that this check was
7759 -- revised by AI-229, because the originally Ada 95 rule
7760 -- was too lax. The original rule only applied when the
7761 -- subprogram was declared within the body of the generic,
7762 -- which allowed the possibility of dangling references).
7763 -- The rule was also too strict in some case, in that it
7764 -- didn't permit the access to be declared in the generic
7765 -- spec, whereas the revised rule does (as long as it's not
7768 -- There are a couple of subtleties of the test for applying
7769 -- the check that are worth noting. First, we only apply it
7770 -- when the levels of the subprogram and access type are the
7771 -- same (the case where the subprogram is statically deeper
7772 -- was applied above, and the case where the type is deeper
7773 -- is always safe). Second, we want the check to apply
7774 -- within nested generic bodies and generic child unit
7775 -- bodies, but not to apply to an attribute that appears in
7776 -- the generic unit's specification. This is done by testing
7777 -- that the attribute's innermost enclosing generic body is
7778 -- not the same as the innermost generic body enclosing the
7779 -- generic unit where the subprogram is declared (we don't
7780 -- want the check to apply when the access attribute is in
7781 -- the spec and there's some other generic body enclosing
7782 -- generic). Finally, there's no point applying the check
7783 -- when within an instance, because any violations will have
7784 -- been caught by the compilation of the generic unit.
7786 elsif Attr_Id = Attribute_Access
7787 and then not In_Instance
7788 and then Present (Enclosing_Generic_Unit (Entity (P)))
7789 and then Present (Enclosing_Generic_Body (N))
7790 and then Enclosing_Generic_Body (N) /=
7791 Enclosing_Generic_Body
7792 (Enclosing_Generic_Unit (Entity (P)))
7793 and then Subprogram_Access_Level (Entity (P)) =
7794 Type_Access_Level (Btyp)
7795 and then Ekind (Btyp) /=
7796 E_Anonymous_Access_Subprogram_Type
7797 and then Ekind (Btyp) /=
7798 E_Anonymous_Access_Protected_Subprogram_Type
7800 -- The attribute type's ultimate ancestor must be
7801 -- declared within the same generic unit as the
7802 -- subprogram is declared. The error message is
7803 -- specialized to say "ancestor" for the case where
7804 -- the access type is not its own ancestor, since
7805 -- saying simply "access type" would be very confusing.
7807 if Enclosing_Generic_Unit (Entity (P)) /=
7808 Enclosing_Generic_Unit (Root_Type (Btyp))
7811 ("''Access attribute not allowed in generic body",
7814 if Root_Type (Btyp) = Btyp then
7817 "access type & is declared outside " &
7818 "generic unit (RM 3.10.2(32))", N, Btyp);
7821 ("\because ancestor of " &
7822 "access type & is declared outside " &
7823 "generic unit (RM 3.10.2(32))", N, Btyp);
7827 ("\move ''Access to private part, or " &
7828 "(Ada 2005) use anonymous access type instead of &",
7831 -- If the ultimate ancestor of the attribute's type is
7832 -- a formal type, then the attribute is illegal because
7833 -- the actual type might be declared at a higher level.
7834 -- The error message is specialized to say "ancestor"
7835 -- for the case where the access type is not its own
7836 -- ancestor, since saying simply "access type" would be
7839 elsif Is_Generic_Type (Root_Type (Btyp)) then
7840 if Root_Type (Btyp) = Btyp then
7842 ("access type must not be a generic formal type",
7846 ("ancestor access type must not be a generic " &
7853 -- If this is a renaming, an inherited operation, or a
7854 -- subprogram instance, use the original entity. This may make
7855 -- the node type-inconsistent, so this transformation can only
7856 -- be done if the node will not be reanalyzed. In particular,
7857 -- if it is within a default expression, the transformation
7858 -- must be delayed until the default subprogram is created for
7859 -- it, when the enclosing subprogram is frozen.
7861 if Is_Entity_Name (P)
7862 and then Is_Overloadable (Entity (P))
7863 and then Present (Alias (Entity (P)))
7864 and then Expander_Active
7867 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
7870 elsif Nkind (P) = N_Selected_Component
7871 and then Is_Overloadable (Entity (Selector_Name (P)))
7873 -- Protected operation. If operation is overloaded, must
7874 -- disambiguate. Prefix that denotes protected object itself
7875 -- is resolved with its own type.
7877 if Attr_Id = Attribute_Unchecked_Access then
7878 Error_Msg_Name_1 := Aname;
7880 ("attribute% cannot be applied to protected operation", P);
7883 Resolve (Prefix (P));
7884 Generate_Reference (Entity (Selector_Name (P)), P);
7886 elsif Is_Overloaded (P) then
7888 -- Use the designated type of the context to disambiguate
7889 -- Note that this was not strictly conformant to Ada 95,
7890 -- but was the implementation adopted by most Ada 95 compilers.
7891 -- The use of the context type to resolve an Access attribute
7892 -- reference is now mandated in AI-235 for Ada 2005.
7895 Index : Interp_Index;
7899 Get_First_Interp (P, Index, It);
7900 while Present (It.Typ) loop
7901 if Covers (Designated_Type (Typ), It.Typ) then
7902 Resolve (P, It.Typ);
7906 Get_Next_Interp (Index, It);
7913 -- X'Access is illegal if X denotes a constant and the access type
7914 -- is access-to-variable. Same for 'Unchecked_Access. The rule
7915 -- does not apply to 'Unrestricted_Access. If the reference is a
7916 -- default-initialized aggregate component for a self-referential
7917 -- type the reference is legal.
7919 if not (Ekind (Btyp) = E_Access_Subprogram_Type
7920 or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
7921 or else (Is_Record_Type (Btyp)
7923 Present (Corresponding_Remote_Type (Btyp)))
7924 or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type
7925 or else Ekind (Btyp)
7926 = E_Anonymous_Access_Protected_Subprogram_Type
7927 or else Is_Access_Constant (Btyp)
7928 or else Is_Variable (P)
7929 or else Attr_Id = Attribute_Unrestricted_Access)
7931 if Is_Entity_Name (P)
7932 and then Is_Type (Entity (P))
7934 -- Legality of a self-reference through an access
7935 -- attribute has been verified in Analyze_Access_Attribute.
7939 elsif Comes_From_Source (N) then
7940 Error_Msg_F ("access-to-variable designates constant", P);
7944 Des_Btyp := Designated_Type (Btyp);
7946 if Ada_Version >= Ada_05
7947 and then Is_Incomplete_Type (Des_Btyp)
7949 -- Ada 2005 (AI-412): If the (sub)type is a limited view of an
7950 -- imported entity, and the non-limited view is visible, make
7951 -- use of it. If it is an incomplete subtype, use the base type
7954 if From_With_Type (Des_Btyp)
7955 and then Present (Non_Limited_View (Des_Btyp))
7957 Des_Btyp := Non_Limited_View (Des_Btyp);
7959 elsif Ekind (Des_Btyp) = E_Incomplete_Subtype then
7960 Des_Btyp := Etype (Des_Btyp);
7964 if (Attr_Id = Attribute_Access
7966 Attr_Id = Attribute_Unchecked_Access)
7967 and then (Ekind (Btyp) = E_General_Access_Type
7968 or else Ekind (Btyp) = E_Anonymous_Access_Type)
7970 -- Ada 2005 (AI-230): Check the accessibility of anonymous
7971 -- access types for stand-alone objects, record and array
7972 -- components, and return objects. For a component definition
7973 -- the level is the same of the enclosing composite type.
7975 if Ada_Version >= Ada_05
7976 and then Is_Local_Anonymous_Access (Btyp)
7977 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
7978 and then Attr_Id = Attribute_Access
7980 -- In an instance, this is a runtime check, but one we
7981 -- know will fail, so generate an appropriate warning.
7983 if In_Instance_Body then
7985 ("?non-local pointer cannot point to local object", P);
7987 ("\?Program_Error will be raised at run time", P);
7989 Make_Raise_Program_Error (Loc,
7990 Reason => PE_Accessibility_Check_Failed));
7995 ("non-local pointer cannot point to local object", P);
7999 if Is_Dependent_Component_Of_Mutable_Object (P) then
8001 ("illegal attribute for discriminant-dependent component",
8005 -- Check static matching rule of 3.10.2(27). Nominal subtype
8006 -- of the prefix must statically match the designated type.
8008 Nom_Subt := Etype (P);
8010 if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then
8011 Nom_Subt := Base_Type (Nom_Subt);
8014 if Is_Tagged_Type (Designated_Type (Typ)) then
8016 -- If the attribute is in the context of an access
8017 -- parameter, then the prefix is allowed to be of the
8018 -- class-wide type (by AI-127).
8020 if Ekind (Typ) = E_Anonymous_Access_Type then
8021 if not Covers (Designated_Type (Typ), Nom_Subt)
8022 and then not Covers (Nom_Subt, Designated_Type (Typ))
8028 Desig := Designated_Type (Typ);
8030 if Is_Class_Wide_Type (Desig) then
8031 Desig := Etype (Desig);
8034 if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then
8039 ("type of prefix: & not compatible",
8042 ("\with &, the expected designated type",
8043 P, Designated_Type (Typ));
8048 elsif not Covers (Designated_Type (Typ), Nom_Subt)
8050 (not Is_Class_Wide_Type (Designated_Type (Typ))
8051 and then Is_Class_Wide_Type (Nom_Subt))
8054 ("type of prefix: & is not covered", P, Nom_Subt);
8056 ("\by &, the expected designated type" &
8057 " (RM 3.10.2 (27))", P, Designated_Type (Typ));
8060 if Is_Class_Wide_Type (Designated_Type (Typ))
8061 and then Has_Discriminants (Etype (Designated_Type (Typ)))
8062 and then Is_Constrained (Etype (Designated_Type (Typ)))
8063 and then Designated_Type (Typ) /= Nom_Subt
8065 Apply_Discriminant_Check
8066 (N, Etype (Designated_Type (Typ)));
8069 -- Ada 2005 (AI-363): Require static matching when designated
8070 -- type has discriminants and a constrained partial view, since
8071 -- in general objects of such types are mutable, so we can't
8072 -- allow the access value to designate a constrained object
8073 -- (because access values must be assumed to designate mutable
8074 -- objects when designated type does not impose a constraint).
8076 elsif Subtypes_Statically_Match (Des_Btyp, Nom_Subt) then
8079 elsif Has_Discriminants (Designated_Type (Typ))
8080 and then not Is_Constrained (Des_Btyp)
8082 (Ada_Version < Ada_05
8084 not Has_Constrained_Partial_View
8085 (Designated_Type (Base_Type (Typ))))
8091 ("object subtype must statically match "
8092 & "designated subtype", P);
8094 if Is_Entity_Name (P)
8095 and then Is_Array_Type (Designated_Type (Typ))
8098 D : constant Node_Id := Declaration_Node (Entity (P));
8101 Error_Msg_N ("aliased object has explicit bounds?",
8103 Error_Msg_N ("\declare without bounds"
8104 & " (and with explicit initialization)?", D);
8105 Error_Msg_N ("\for use with unconstrained access?", D);
8110 -- Check the static accessibility rule of 3.10.2(28).
8111 -- Note that this check is not performed for the
8112 -- case of an anonymous access type, since the access
8113 -- attribute is always legal in such a context.
8115 if Attr_Id /= Attribute_Unchecked_Access
8116 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
8117 and then Ekind (Btyp) = E_General_Access_Type
8119 Accessibility_Message;
8124 if Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8126 Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type
8128 if Is_Entity_Name (P)
8129 and then not Is_Protected_Type (Scope (Entity (P)))
8131 Error_Msg_F ("context requires a protected subprogram", P);
8133 -- Check accessibility of protected object against that of the
8134 -- access type, but only on user code, because the expander
8135 -- creates access references for handlers. If the context is an
8136 -- anonymous_access_to_protected, there are no accessibility
8137 -- checks either. Omit check entirely for Unrestricted_Access.
8139 elsif Object_Access_Level (P) > Type_Access_Level (Btyp)
8140 and then Comes_From_Source (N)
8141 and then Ekind (Btyp) = E_Access_Protected_Subprogram_Type
8142 and then Attr_Id /= Attribute_Unrestricted_Access
8144 Accessibility_Message;
8148 elsif (Ekind (Btyp) = E_Access_Subprogram_Type
8150 Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type)
8151 and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
8153 Error_Msg_F ("context requires a non-protected subprogram", P);
8156 -- The context cannot be a pool-specific type, but this is a
8157 -- legality rule, not a resolution rule, so it must be checked
8158 -- separately, after possibly disambiguation (see AI-245).
8160 if Ekind (Btyp) = E_Access_Type
8161 and then Attr_Id /= Attribute_Unrestricted_Access
8163 Wrong_Type (N, Typ);
8166 -- The context may be a constrained access type (however ill-
8167 -- advised such subtypes might be) so in order to generate a
8168 -- constraint check when needed set the type of the attribute
8169 -- reference to the base type of the context.
8171 Set_Etype (N, Btyp);
8173 -- Check for incorrect atomic/volatile reference (RM C.6(12))
8175 if Attr_Id /= Attribute_Unrestricted_Access then
8176 if Is_Atomic_Object (P)
8177 and then not Is_Atomic (Designated_Type (Typ))
8180 ("access to atomic object cannot yield access-to-" &
8181 "non-atomic type", P);
8183 elsif Is_Volatile_Object (P)
8184 and then not Is_Volatile (Designated_Type (Typ))
8187 ("access to volatile object cannot yield access-to-" &
8188 "non-volatile type", P);
8192 if Is_Entity_Name (P) then
8193 Set_Address_Taken (Entity (P));
8195 end Access_Attribute;
8201 -- Deal with resolving the type for Address attribute, overloading
8202 -- is not permitted here, since there is no context to resolve it.
8204 when Attribute_Address | Attribute_Code_Address =>
8205 Address_Attribute : begin
8207 -- To be safe, assume that if the address of a variable is taken,
8208 -- it may be modified via this address, so note modification.
8210 if Is_Variable (P) then
8211 Note_Possible_Modification (P, Sure => False);
8214 if Nkind (P) in N_Subexpr
8215 and then Is_Overloaded (P)
8217 Get_First_Interp (P, Index, It);
8218 Get_Next_Interp (Index, It);
8220 if Present (It.Nam) then
8221 Error_Msg_Name_1 := Aname;
8223 ("prefix of % attribute cannot be overloaded", P);
8227 if not Is_Entity_Name (P)
8228 or else not Is_Overloadable (Entity (P))
8230 if not Is_Task_Type (Etype (P))
8231 or else Nkind (P) = N_Explicit_Dereference
8237 -- If this is the name of a derived subprogram, or that of a
8238 -- generic actual, the address is that of the original entity.
8240 if Is_Entity_Name (P)
8241 and then Is_Overloadable (Entity (P))
8242 and then Present (Alias (Entity (P)))
8245 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
8248 if Is_Entity_Name (P) then
8249 Set_Address_Taken (Entity (P));
8252 if Nkind (P) = N_Slice then
8254 -- Arr (X .. Y)'address is identical to Arr (X)'address,
8255 -- even if the array is packed and the slice itself is not
8256 -- addressable. Transform the prefix into an indexed component.
8258 -- Note that the transformation is safe only if we know that
8259 -- the slice is non-null. That is because a null slice can have
8260 -- an out of bounds index value.
8262 -- Right now, gigi blows up if given 'Address on a slice as a
8263 -- result of some incorrect freeze nodes generated by the front
8264 -- end, and this covers up that bug in one case, but the bug is
8265 -- likely still there in the cases not handled by this code ???
8267 -- It's not clear what 'Address *should* return for a null
8268 -- slice with out of bounds indexes, this might be worth an ARG
8271 -- One approach would be to do a length check unconditionally,
8272 -- and then do the transformation below unconditionally, but
8273 -- analyze with checks off, avoiding the problem of the out of
8274 -- bounds index. This approach would interpret the address of
8275 -- an out of bounds null slice as being the address where the
8276 -- array element would be if there was one, which is probably
8277 -- as reasonable an interpretation as any ???
8280 Loc : constant Source_Ptr := Sloc (P);
8281 D : constant Node_Id := Discrete_Range (P);
8285 if Is_Entity_Name (D)
8288 (Type_Low_Bound (Entity (D)),
8289 Type_High_Bound (Entity (D)))
8292 Make_Attribute_Reference (Loc,
8293 Prefix => (New_Occurrence_Of (Entity (D), Loc)),
8294 Attribute_Name => Name_First);
8296 elsif Nkind (D) = N_Range
8297 and then Not_Null_Range (Low_Bound (D), High_Bound (D))
8299 Lo := Low_Bound (D);
8305 if Present (Lo) then
8307 Make_Indexed_Component (Loc,
8308 Prefix => Relocate_Node (Prefix (P)),
8309 Expressions => New_List (Lo)));
8311 Analyze_And_Resolve (P);
8315 end Address_Attribute;
8321 -- Prefix of the AST_Entry attribute is an entry name which must
8322 -- not be resolved, since this is definitely not an entry call.
8324 when Attribute_AST_Entry =>
8331 -- Prefix of Body_Version attribute can be a subprogram name which
8332 -- must not be resolved, since this is not a call.
8334 when Attribute_Body_Version =>
8341 -- Prefix of Caller attribute is an entry name which must not
8342 -- be resolved, since this is definitely not an entry call.
8344 when Attribute_Caller =>
8351 -- Shares processing with Address attribute
8357 -- If the prefix of the Count attribute is an entry name it must not
8358 -- be resolved, since this is definitely not an entry call. However,
8359 -- if it is an element of an entry family, the index itself may
8360 -- have to be resolved because it can be a general expression.
8362 when Attribute_Count =>
8363 if Nkind (P) = N_Indexed_Component
8364 and then Is_Entity_Name (Prefix (P))
8367 Indx : constant Node_Id := First (Expressions (P));
8368 Fam : constant Entity_Id := Entity (Prefix (P));
8370 Resolve (Indx, Entry_Index_Type (Fam));
8371 Apply_Range_Check (Indx, Entry_Index_Type (Fam));
8379 -- Prefix of the Elaborated attribute is a subprogram name which
8380 -- must not be resolved, since this is definitely not a call. Note
8381 -- that it is a library unit, so it cannot be overloaded here.
8383 when Attribute_Elaborated =>
8390 -- Prefix of Enabled attribute is a check name, which must be treated
8391 -- specially and not touched by Resolve.
8393 when Attribute_Enabled =>
8396 --------------------
8397 -- Mechanism_Code --
8398 --------------------
8400 -- Prefix of the Mechanism_Code attribute is a function name
8401 -- which must not be resolved. Should we check for overloaded ???
8403 when Attribute_Mechanism_Code =>
8410 -- Most processing is done in sem_dist, after determining the
8411 -- context type. Node is rewritten as a conversion to a runtime call.
8413 when Attribute_Partition_ID =>
8414 Process_Partition_Id (N);
8421 when Attribute_Pool_Address =>
8428 -- We replace the Range attribute node with a range expression
8429 -- whose bounds are the 'First and 'Last attributes applied to the
8430 -- same prefix. The reason that we do this transformation here
8431 -- instead of in the expander is that it simplifies other parts of
8432 -- the semantic analysis which assume that the Range has been
8433 -- replaced; thus it must be done even when in semantic-only mode
8434 -- (note that the RM specifically mentions this equivalence, we
8435 -- take care that the prefix is only evaluated once).
8437 when Attribute_Range => Range_Attribute :
8443 if not Is_Entity_Name (P)
8444 or else not Is_Type (Entity (P))
8450 Make_Attribute_Reference (Loc,
8452 Duplicate_Subexpr (P, Name_Req => True),
8453 Attribute_Name => Name_Last,
8454 Expressions => Expressions (N));
8457 Make_Attribute_Reference (Loc,
8459 Attribute_Name => Name_First,
8460 Expressions => Expressions (N));
8462 -- If the original was marked as Must_Not_Freeze (see code
8463 -- in Sem_Ch3.Make_Index), then make sure the rewriting
8464 -- does not freeze either.
8466 if Must_Not_Freeze (N) then
8467 Set_Must_Not_Freeze (HB);
8468 Set_Must_Not_Freeze (LB);
8469 Set_Must_Not_Freeze (Prefix (HB));
8470 Set_Must_Not_Freeze (Prefix (LB));
8473 if Raises_Constraint_Error (Prefix (N)) then
8475 -- Preserve Sloc of prefix in the new bounds, so that
8476 -- the posted warning can be removed if we are within
8477 -- unreachable code.
8479 Set_Sloc (LB, Sloc (Prefix (N)));
8480 Set_Sloc (HB, Sloc (Prefix (N)));
8483 Rewrite (N, Make_Range (Loc, LB, HB));
8484 Analyze_And_Resolve (N, Typ);
8486 -- Normally after resolving attribute nodes, Eval_Attribute
8487 -- is called to do any possible static evaluation of the node.
8488 -- However, here since the Range attribute has just been
8489 -- transformed into a range expression it is no longer an
8490 -- attribute node and therefore the call needs to be avoided
8491 -- and is accomplished by simply returning from the procedure.
8494 end Range_Attribute;
8500 -- We will only come here during the prescan of a spec expression
8501 -- containing a Result attribute. In that case the proper Etype has
8502 -- already been set, and nothing more needs to be done here.
8504 when Attribute_Result =>
8511 -- Prefix must not be resolved in this case, since it is not a
8512 -- real entity reference. No action of any kind is require!
8514 when Attribute_UET_Address =>
8517 ----------------------
8518 -- Unchecked_Access --
8519 ----------------------
8521 -- Processing is shared with Access
8523 -------------------------
8524 -- Unrestricted_Access --
8525 -------------------------
8527 -- Processing is shared with Access
8533 -- Apply range check. Note that we did not do this during the
8534 -- analysis phase, since we wanted Eval_Attribute to have a
8535 -- chance at finding an illegal out of range value.
8537 when Attribute_Val =>
8539 -- Note that we do our own Eval_Attribute call here rather than
8540 -- use the common one, because we need to do processing after
8541 -- the call, as per above comment.
8545 -- Eval_Attribute may replace the node with a raise CE, or
8546 -- fold it to a constant. Obviously we only apply a scalar
8547 -- range check if this did not happen!
8549 if Nkind (N) = N_Attribute_Reference
8550 and then Attribute_Name (N) = Name_Val
8552 Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
8561 -- Prefix of Version attribute can be a subprogram name which
8562 -- must not be resolved, since this is not a call.
8564 when Attribute_Version =>
8567 ----------------------
8568 -- Other Attributes --
8569 ----------------------
8571 -- For other attributes, resolve prefix unless it is a type. If
8572 -- the attribute reference itself is a type name ('Base and 'Class)
8573 -- then this is only legal within a task or protected record.
8576 if not Is_Entity_Name (P)
8577 or else not Is_Type (Entity (P))
8582 -- If the attribute reference itself is a type name ('Base,
8583 -- 'Class) then this is only legal within a task or protected
8584 -- record. What is this all about ???
8586 if Is_Entity_Name (N)
8587 and then Is_Type (Entity (N))
8589 if Is_Concurrent_Type (Entity (N))
8590 and then In_Open_Scopes (Entity (P))
8595 ("invalid use of subtype name in expression or call", N);
8599 -- For attributes whose argument may be a string, complete
8600 -- resolution of argument now. This avoids premature expansion
8601 -- (and the creation of transient scopes) before the attribute
8602 -- reference is resolved.
8605 when Attribute_Value =>
8606 Resolve (First (Expressions (N)), Standard_String);
8608 when Attribute_Wide_Value =>
8609 Resolve (First (Expressions (N)), Standard_Wide_String);
8611 when Attribute_Wide_Wide_Value =>
8612 Resolve (First (Expressions (N)), Standard_Wide_Wide_String);
8614 when others => null;
8617 -- If the prefix of the attribute is a class-wide type then it
8618 -- will be expanded into a dispatching call to a predefined
8619 -- primitive. Therefore we must check for potential violation
8620 -- of such restriction.
8622 if Is_Class_Wide_Type (Etype (P)) then
8623 Check_Restriction (No_Dispatching_Calls, N);
8627 -- Normally the Freezing is done by Resolve but sometimes the Prefix
8628 -- is not resolved, in which case the freezing must be done now.
8630 Freeze_Expression (P);
8632 -- Finally perform static evaluation on the attribute reference
8635 end Resolve_Attribute;
8637 --------------------------------
8638 -- Stream_Attribute_Available --
8639 --------------------------------
8641 function Stream_Attribute_Available
8643 Nam : TSS_Name_Type;
8644 Partial_View : Node_Id := Empty) return Boolean
8646 Etyp : Entity_Id := Typ;
8648 -- Start of processing for Stream_Attribute_Available
8651 -- We need some comments in this body ???
8653 if Has_Stream_Attribute_Definition (Typ, Nam) then
8657 if Is_Class_Wide_Type (Typ) then
8658 return not Is_Limited_Type (Typ)
8659 or else Stream_Attribute_Available (Etype (Typ), Nam);
8662 if Nam = TSS_Stream_Input
8663 and then Is_Abstract_Type (Typ)
8664 and then not Is_Class_Wide_Type (Typ)
8669 if not (Is_Limited_Type (Typ)
8670 or else (Present (Partial_View)
8671 and then Is_Limited_Type (Partial_View)))
8676 -- In Ada 2005, Input can invoke Read, and Output can invoke Write
8678 if Nam = TSS_Stream_Input
8679 and then Ada_Version >= Ada_05
8680 and then Stream_Attribute_Available (Etyp, TSS_Stream_Read)
8684 elsif Nam = TSS_Stream_Output
8685 and then Ada_Version >= Ada_05
8686 and then Stream_Attribute_Available (Etyp, TSS_Stream_Write)
8691 -- Case of Read and Write: check for attribute definition clause that
8692 -- applies to an ancestor type.
8694 while Etype (Etyp) /= Etyp loop
8695 Etyp := Etype (Etyp);
8697 if Has_Stream_Attribute_Definition (Etyp, Nam) then
8702 if Ada_Version < Ada_05 then
8704 -- In Ada 95 mode, also consider a non-visible definition
8707 Btyp : constant Entity_Id := Implementation_Base_Type (Typ);
8710 and then Stream_Attribute_Available
8711 (Btyp, Nam, Partial_View => Typ);
8716 end Stream_Attribute_Available;