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 Atree; use Atree;
27 with Checks; use Checks;
28 with Einfo; use Einfo;
29 with Errout; use Errout;
30 with Exp_Tss; use Exp_Tss;
31 with Exp_Util; use Exp_Util;
33 with Lib.Xref; use Lib.Xref;
34 with Namet; use Namet;
35 with Nlists; use Nlists;
36 with Nmake; use Nmake;
38 with Restrict; use Restrict;
39 with Rident; use Rident;
40 with Rtsfind; use Rtsfind;
42 with Sem_Aux; use Sem_Aux;
43 with Sem_Ch8; use Sem_Ch8;
44 with Sem_Eval; use Sem_Eval;
45 with Sem_Res; use Sem_Res;
46 with Sem_Type; use Sem_Type;
47 with Sem_Util; use Sem_Util;
48 with Sem_Warn; use Sem_Warn;
49 with Snames; use Snames;
50 with Stand; use Stand;
51 with Sinfo; use Sinfo;
53 with Targparm; use Targparm;
54 with Ttypes; use Ttypes;
55 with Tbuild; use Tbuild;
56 with Urealp; use Urealp;
58 with GNAT.Heap_Sort_G;
60 package body Sem_Ch13 is
62 SSU : constant Pos := System_Storage_Unit;
63 -- Convenient short hand for commonly used constant
65 -----------------------
66 -- Local Subprograms --
67 -----------------------
69 procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id);
70 -- This routine is called after setting the Esize of type entity Typ.
71 -- The purpose is to deal with the situation where an alignment has been
72 -- inherited from a derived type that is no longer appropriate for the
73 -- new Esize value. In this case, we reset the Alignment to unknown.
75 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id);
76 -- Given two entities for record components or discriminants, checks
77 -- if they have overlapping component clauses and issues errors if so.
79 function Get_Alignment_Value (Expr : Node_Id) return Uint;
80 -- Given the expression for an alignment value, returns the corresponding
81 -- Uint value. If the value is inappropriate, then error messages are
82 -- posted as required, and a value of No_Uint is returned.
84 function Is_Operational_Item (N : Node_Id) return Boolean;
85 -- A specification for a stream attribute is allowed before the full
86 -- type is declared, as explained in AI-00137 and the corrigendum.
87 -- Attributes that do not specify a representation characteristic are
88 -- operational attributes.
90 function Address_Aliased_Entity (N : Node_Id) return Entity_Id;
91 -- If expression N is of the form E'Address, return E
93 procedure New_Stream_Subprogram
98 -- Create a subprogram renaming of a given stream attribute to the
99 -- designated subprogram and then in the tagged case, provide this as a
100 -- primitive operation, or in the non-tagged case make an appropriate TSS
101 -- entry. This is more properly an expansion activity than just semantics,
102 -- but the presence of user-defined stream functions for limited types is a
103 -- legality check, which is why this takes place here rather than in
104 -- exp_ch13, where it was previously. Nam indicates the name of the TSS
105 -- function to be generated.
107 -- To avoid elaboration anomalies with freeze nodes, for untagged types
108 -- we generate both a subprogram declaration and a subprogram renaming
109 -- declaration, so that the attribute specification is handled as a
110 -- renaming_as_body. For tagged types, the specification is one of the
113 ----------------------------------------------
114 -- Table for Validate_Unchecked_Conversions --
115 ----------------------------------------------
117 -- The following table collects unchecked conversions for validation.
118 -- Entries are made by Validate_Unchecked_Conversion and then the
119 -- call to Validate_Unchecked_Conversions does the actual error
120 -- checking and posting of warnings. The reason for this delayed
121 -- processing is to take advantage of back-annotations of size and
122 -- alignment values performed by the back end.
124 type UC_Entry is record
125 Enode : Node_Id; -- node used for posting warnings
126 Source : Entity_Id; -- source type for unchecked conversion
127 Target : Entity_Id; -- target type for unchecked conversion
130 package Unchecked_Conversions is new Table.Table (
131 Table_Component_Type => UC_Entry,
132 Table_Index_Type => Int,
133 Table_Low_Bound => 1,
135 Table_Increment => 200,
136 Table_Name => "Unchecked_Conversions");
138 ----------------------------------------
139 -- Table for Validate_Address_Clauses --
140 ----------------------------------------
142 -- If an address clause has the form
144 -- for X'Address use Expr
146 -- where Expr is of the form Y'Address or recursively is a reference
147 -- to a constant of either of these forms, and X and Y are entities of
148 -- objects, then if Y has a smaller alignment than X, that merits a
149 -- warning about possible bad alignment. The following table collects
150 -- address clauses of this kind. We put these in a table so that they
151 -- can be checked after the back end has completed annotation of the
152 -- alignments of objects, since we can catch more cases that way.
154 type Address_Clause_Check_Record is record
156 -- The address clause
159 -- The entity of the object overlaying Y
162 -- The entity of the object being overlaid
165 package Address_Clause_Checks is new Table.Table (
166 Table_Component_Type => Address_Clause_Check_Record,
167 Table_Index_Type => Int,
168 Table_Low_Bound => 1,
170 Table_Increment => 200,
171 Table_Name => "Address_Clause_Checks");
173 ----------------------------
174 -- Address_Aliased_Entity --
175 ----------------------------
177 function Address_Aliased_Entity (N : Node_Id) return Entity_Id is
179 if Nkind (N) = N_Attribute_Reference
180 and then Attribute_Name (N) = Name_Address
187 while Nkind_In (P, N_Selected_Component, N_Indexed_Component) loop
191 if Is_Entity_Name (P) then
198 end Address_Aliased_Entity;
200 -----------------------------------------
201 -- Adjust_Record_For_Reverse_Bit_Order --
202 -----------------------------------------
204 procedure Adjust_Record_For_Reverse_Bit_Order (R : Entity_Id) is
205 Max_Machine_Scalar_Size : constant Uint :=
207 (Standard_Long_Long_Integer_Size);
208 -- We use this as the maximum machine scalar size in the sense of AI-133
212 SSU : constant Uint := UI_From_Int (System_Storage_Unit);
215 -- This first loop through components does two things. First it deals
216 -- with the case of components with component clauses whose length is
217 -- greater than the maximum machine scalar size (either accepting them
218 -- or rejecting as needed). Second, it counts the number of components
219 -- with component clauses whose length does not exceed this maximum for
223 Comp := First_Component_Or_Discriminant (R);
224 while Present (Comp) loop
226 CC : constant Node_Id := Component_Clause (Comp);
231 Fbit : constant Uint := Static_Integer (First_Bit (CC));
234 -- Case of component with size > max machine scalar
236 if Esize (Comp) > Max_Machine_Scalar_Size then
238 -- Must begin on byte boundary
240 if Fbit mod SSU /= 0 then
242 ("illegal first bit value for reverse bit order",
244 Error_Msg_Uint_1 := SSU;
245 Error_Msg_Uint_2 := Max_Machine_Scalar_Size;
248 ("\must be a multiple of ^ if size greater than ^",
251 -- Must end on byte boundary
253 elsif Esize (Comp) mod SSU /= 0 then
255 ("illegal last bit value for reverse bit order",
257 Error_Msg_Uint_1 := SSU;
258 Error_Msg_Uint_2 := Max_Machine_Scalar_Size;
261 ("\must be a multiple of ^ if size greater than ^",
264 -- OK, give warning if enabled
266 elsif Warn_On_Reverse_Bit_Order then
268 ("multi-byte field specified with non-standard"
269 & " Bit_Order?", CC);
271 if Bytes_Big_Endian then
273 ("\bytes are not reversed "
274 & "(component is big-endian)?", CC);
277 ("\bytes are not reversed "
278 & "(component is little-endian)?", CC);
282 -- Case where size is not greater than max machine
283 -- scalar. For now, we just count these.
286 Num_CC := Num_CC + 1;
292 Next_Component_Or_Discriminant (Comp);
295 -- We need to sort the component clauses on the basis of the Position
296 -- values in the clause, so we can group clauses with the same Position.
297 -- together to determine the relevant machine scalar size.
300 Comps : array (0 .. Num_CC) of Entity_Id;
301 -- Array to collect component and discriminant entities. The data
302 -- starts at index 1, the 0'th entry is for the sort routine.
304 function CP_Lt (Op1, Op2 : Natural) return Boolean;
305 -- Compare routine for Sort
307 procedure CP_Move (From : Natural; To : Natural);
308 -- Move routine for Sort
310 package Sorting is new GNAT.Heap_Sort_G (CP_Move, CP_Lt);
314 -- Start and stop positions in component list of set of components
315 -- with the same starting position (that constitute components in
316 -- a single machine scalar).
319 -- Maximum last bit value of any component in this set
322 -- Corresponding machine scalar size
328 function CP_Lt (Op1, Op2 : Natural) return Boolean is
330 return Position (Component_Clause (Comps (Op1))) <
331 Position (Component_Clause (Comps (Op2)));
338 procedure CP_Move (From : Natural; To : Natural) is
340 Comps (To) := Comps (From);
344 -- Collect the component clauses
347 Comp := First_Component_Or_Discriminant (R);
348 while Present (Comp) loop
349 if Present (Component_Clause (Comp))
350 and then Esize (Comp) <= Max_Machine_Scalar_Size
352 Num_CC := Num_CC + 1;
353 Comps (Num_CC) := Comp;
356 Next_Component_Or_Discriminant (Comp);
359 -- Sort by ascending position number
361 Sorting.Sort (Num_CC);
363 -- We now have all the components whose size does not exceed the max
364 -- machine scalar value, sorted by starting position. In this loop
365 -- we gather groups of clauses starting at the same position, to
366 -- process them in accordance with Ada 2005 AI-133.
369 while Stop < Num_CC loop
373 Static_Integer (Last_Bit (Component_Clause (Comps (Start))));
374 while Stop < Num_CC loop
376 (Position (Component_Clause (Comps (Stop + 1)))) =
378 (Position (Component_Clause (Comps (Stop))))
385 (Last_Bit (Component_Clause (Comps (Stop)))));
391 -- Now we have a group of component clauses from Start to Stop
392 -- whose positions are identical, and MaxL is the maximum last bit
393 -- value of any of these components.
395 -- We need to determine the corresponding machine scalar size.
396 -- This loop assumes that machine scalar sizes are even, and that
397 -- each possible machine scalar has twice as many bits as the
400 MSS := Max_Machine_Scalar_Size;
402 and then (MSS / 2) >= SSU
403 and then (MSS / 2) > MaxL
408 -- Here is where we fix up the Component_Bit_Offset value to
409 -- account for the reverse bit order. Some examples of what needs
410 -- to be done for the case of a machine scalar size of 8 are:
412 -- First_Bit .. Last_Bit Component_Bit_Offset
424 -- The general rule is that the first bit is obtained by
425 -- subtracting the old ending bit from machine scalar size - 1.
427 for C in Start .. Stop loop
429 Comp : constant Entity_Id := Comps (C);
430 CC : constant Node_Id := Component_Clause (Comp);
431 LB : constant Uint := Static_Integer (Last_Bit (CC));
432 NFB : constant Uint := MSS - Uint_1 - LB;
433 NLB : constant Uint := NFB + Esize (Comp) - 1;
434 Pos : constant Uint := Static_Integer (Position (CC));
437 if Warn_On_Reverse_Bit_Order then
438 Error_Msg_Uint_1 := MSS;
440 ("info: reverse bit order in machine " &
441 "scalar of length^?", First_Bit (CC));
442 Error_Msg_Uint_1 := NFB;
443 Error_Msg_Uint_2 := NLB;
445 if Bytes_Big_Endian then
447 ("?\info: big-endian range for "
448 & "component & is ^ .. ^",
449 First_Bit (CC), Comp);
452 ("?\info: little-endian range "
453 & "for component & is ^ .. ^",
454 First_Bit (CC), Comp);
458 Set_Component_Bit_Offset (Comp, Pos * SSU + NFB);
459 Set_Normalized_First_Bit (Comp, NFB mod SSU);
464 end Adjust_Record_For_Reverse_Bit_Order;
466 --------------------------------------
467 -- Alignment_Check_For_Esize_Change --
468 --------------------------------------
470 procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id) is
472 -- If the alignment is known, and not set by a rep clause, and is
473 -- inconsistent with the size being set, then reset it to unknown,
474 -- we assume in this case that the size overrides the inherited
475 -- alignment, and that the alignment must be recomputed.
477 if Known_Alignment (Typ)
478 and then not Has_Alignment_Clause (Typ)
479 and then Esize (Typ) mod (Alignment (Typ) * SSU) /= 0
481 Init_Alignment (Typ);
483 end Alignment_Check_For_Esize_Change;
485 -----------------------
486 -- Analyze_At_Clause --
487 -----------------------
489 -- An at clause is replaced by the corresponding Address attribute
490 -- definition clause that is the preferred approach in Ada 95.
492 procedure Analyze_At_Clause (N : Node_Id) is
493 CS : constant Boolean := Comes_From_Source (N);
496 -- This is an obsolescent feature
498 Check_Restriction (No_Obsolescent_Features, N);
500 if Warn_On_Obsolescent_Feature then
502 ("at clause is an obsolescent feature (RM J.7(2))?", N);
504 ("\use address attribute definition clause instead?", N);
507 -- Rewrite as address clause
510 Make_Attribute_Definition_Clause (Sloc (N),
511 Name => Identifier (N),
512 Chars => Name_Address,
513 Expression => Expression (N)));
515 -- We preserve Comes_From_Source, since logically the clause still
516 -- comes from the source program even though it is changed in form.
518 Set_Comes_From_Source (N, CS);
520 -- Analyze rewritten clause
522 Analyze_Attribute_Definition_Clause (N);
523 end Analyze_At_Clause;
525 -----------------------------------------
526 -- Analyze_Attribute_Definition_Clause --
527 -----------------------------------------
529 procedure Analyze_Attribute_Definition_Clause (N : Node_Id) is
530 Loc : constant Source_Ptr := Sloc (N);
531 Nam : constant Node_Id := Name (N);
532 Attr : constant Name_Id := Chars (N);
533 Expr : constant Node_Id := Expression (N);
534 Id : constant Attribute_Id := Get_Attribute_Id (Attr);
538 FOnly : Boolean := False;
539 -- Reset to True for subtype specific attribute (Alignment, Size)
540 -- and for stream attributes, i.e. those cases where in the call
541 -- to Rep_Item_Too_Late, FOnly is set True so that only the freezing
542 -- rules are checked. Note that the case of stream attributes is not
543 -- clear from the RM, but see AI95-00137. Also, the RM seems to
544 -- disallow Storage_Size for derived task types, but that is also
545 -- clearly unintentional.
547 procedure Analyze_Stream_TSS_Definition (TSS_Nam : TSS_Name_Type);
548 -- Common processing for 'Read, 'Write, 'Input and 'Output attribute
549 -- definition clauses.
551 -----------------------------------
552 -- Analyze_Stream_TSS_Definition --
553 -----------------------------------
555 procedure Analyze_Stream_TSS_Definition (TSS_Nam : TSS_Name_Type) is
556 Subp : Entity_Id := Empty;
561 Is_Read : constant Boolean := (TSS_Nam = TSS_Stream_Read);
563 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
564 -- Return true if the entity is a subprogram with an appropriate
565 -- profile for the attribute being defined.
567 ----------------------
568 -- Has_Good_Profile --
569 ----------------------
571 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
573 Is_Function : constant Boolean := (TSS_Nam = TSS_Stream_Input);
574 Expected_Ekind : constant array (Boolean) of Entity_Kind :=
575 (False => E_Procedure, True => E_Function);
579 if Ekind (Subp) /= Expected_Ekind (Is_Function) then
583 F := First_Formal (Subp);
586 or else Ekind (Etype (F)) /= E_Anonymous_Access_Type
587 or else Designated_Type (Etype (F)) /=
588 Class_Wide_Type (RTE (RE_Root_Stream_Type))
593 if not Is_Function then
597 Expected_Mode : constant array (Boolean) of Entity_Kind :=
598 (False => E_In_Parameter,
599 True => E_Out_Parameter);
601 if Parameter_Mode (F) /= Expected_Mode (Is_Read) then
612 return Base_Type (Typ) = Base_Type (Ent)
613 and then No (Next_Formal (F));
614 end Has_Good_Profile;
616 -- Start of processing for Analyze_Stream_TSS_Definition
621 if not Is_Type (U_Ent) then
622 Error_Msg_N ("local name must be a subtype", Nam);
626 Pnam := TSS (Base_Type (U_Ent), TSS_Nam);
628 -- If Pnam is present, it can be either inherited from an ancestor
629 -- type (in which case it is legal to redefine it for this type), or
630 -- be a previous definition of the attribute for the same type (in
631 -- which case it is illegal).
633 -- In the first case, it will have been analyzed already, and we
634 -- can check that its profile does not match the expected profile
635 -- for a stream attribute of U_Ent. In the second case, either Pnam
636 -- has been analyzed (and has the expected profile), or it has not
637 -- been analyzed yet (case of a type that has not been frozen yet
638 -- and for which the stream attribute has been set using Set_TSS).
641 and then (No (First_Entity (Pnam)) or else Has_Good_Profile (Pnam))
643 Error_Msg_Sloc := Sloc (Pnam);
644 Error_Msg_Name_1 := Attr;
645 Error_Msg_N ("% attribute already defined #", Nam);
651 if Is_Entity_Name (Expr) then
652 if not Is_Overloaded (Expr) then
653 if Has_Good_Profile (Entity (Expr)) then
654 Subp := Entity (Expr);
658 Get_First_Interp (Expr, I, It);
659 while Present (It.Nam) loop
660 if Has_Good_Profile (It.Nam) then
665 Get_Next_Interp (I, It);
670 if Present (Subp) then
671 if Is_Abstract_Subprogram (Subp) then
672 Error_Msg_N ("stream subprogram must not be abstract", Expr);
676 Set_Entity (Expr, Subp);
677 Set_Etype (Expr, Etype (Subp));
679 New_Stream_Subprogram (N, U_Ent, Subp, TSS_Nam);
682 Error_Msg_Name_1 := Attr;
683 Error_Msg_N ("incorrect expression for% attribute", Expr);
685 end Analyze_Stream_TSS_Definition;
687 -- Start of processing for Analyze_Attribute_Definition_Clause
690 if Ignore_Rep_Clauses then
691 Rewrite (N, Make_Null_Statement (Sloc (N)));
698 if Rep_Item_Too_Early (Ent, N) then
702 -- Rep clause applies to full view of incomplete type or private type if
703 -- we have one (if not, this is a premature use of the type). However,
704 -- certain semantic checks need to be done on the specified entity (i.e.
705 -- the private view), so we save it in Ent.
707 if Is_Private_Type (Ent)
708 and then Is_Derived_Type (Ent)
709 and then not Is_Tagged_Type (Ent)
710 and then No (Full_View (Ent))
712 -- If this is a private type whose completion is a derivation from
713 -- another private type, there is no full view, and the attribute
714 -- belongs to the type itself, not its underlying parent.
718 elsif Ekind (Ent) = E_Incomplete_Type then
720 -- The attribute applies to the full view, set the entity of the
721 -- attribute definition accordingly.
723 Ent := Underlying_Type (Ent);
725 Set_Entity (Nam, Ent);
728 U_Ent := Underlying_Type (Ent);
731 -- Complete other routine error checks
733 if Etype (Nam) = Any_Type then
736 elsif Scope (Ent) /= Current_Scope then
737 Error_Msg_N ("entity must be declared in this scope", Nam);
740 elsif No (U_Ent) then
743 elsif Is_Type (U_Ent)
744 and then not Is_First_Subtype (U_Ent)
745 and then Id /= Attribute_Object_Size
746 and then Id /= Attribute_Value_Size
747 and then not From_At_Mod (N)
749 Error_Msg_N ("cannot specify attribute for subtype", Nam);
753 -- Switch on particular attribute
761 -- Address attribute definition clause
763 when Attribute_Address => Address : begin
765 -- A little error check, catch for X'Address use X'Address;
767 if Nkind (Nam) = N_Identifier
768 and then Nkind (Expr) = N_Attribute_Reference
769 and then Attribute_Name (Expr) = Name_Address
770 and then Nkind (Prefix (Expr)) = N_Identifier
771 and then Chars (Nam) = Chars (Prefix (Expr))
774 ("address for & is self-referencing", Prefix (Expr), Ent);
778 -- Not that special case, carry on with analysis of expression
780 Analyze_And_Resolve (Expr, RTE (RE_Address));
782 if Present (Address_Clause (U_Ent)) then
783 Error_Msg_N ("address already given for &", Nam);
785 -- Case of address clause for subprogram
787 elsif Is_Subprogram (U_Ent) then
788 if Has_Homonym (U_Ent) then
790 ("address clause cannot be given " &
791 "for overloaded subprogram",
796 -- For subprograms, all address clauses are permitted, and we
797 -- mark the subprogram as having a deferred freeze so that Gigi
798 -- will not elaborate it too soon.
800 -- Above needs more comments, what is too soon about???
802 Set_Has_Delayed_Freeze (U_Ent);
804 -- Case of address clause for entry
806 elsif Ekind (U_Ent) = E_Entry then
807 if Nkind (Parent (N)) = N_Task_Body then
809 ("entry address must be specified in task spec", Nam);
813 -- For entries, we require a constant address
815 Check_Constant_Address_Clause (Expr, U_Ent);
817 -- Special checks for task types
819 if Is_Task_Type (Scope (U_Ent))
820 and then Comes_From_Source (Scope (U_Ent))
823 ("?entry address declared for entry in task type", N);
825 ("\?only one task can be declared of this type", N);
828 -- Entry address clauses are obsolescent
830 Check_Restriction (No_Obsolescent_Features, N);
832 if Warn_On_Obsolescent_Feature then
834 ("attaching interrupt to task entry is an " &
835 "obsolescent feature (RM J.7.1)?", N);
837 ("\use interrupt procedure instead?", N);
840 -- Case of an address clause for a controlled object which we
841 -- consider to be erroneous.
843 elsif Is_Controlled (Etype (U_Ent))
844 or else Has_Controlled_Component (Etype (U_Ent))
847 ("?controlled object& must not be overlaid", Nam, U_Ent);
849 ("\?Program_Error will be raised at run time", Nam);
850 Insert_Action (Declaration_Node (U_Ent),
851 Make_Raise_Program_Error (Loc,
852 Reason => PE_Overlaid_Controlled_Object));
855 -- Case of address clause for a (non-controlled) object
858 Ekind (U_Ent) = E_Variable
860 Ekind (U_Ent) = E_Constant
863 Expr : constant Node_Id := Expression (N);
864 Aent : constant Entity_Id := Address_Aliased_Entity (Expr);
865 Ent_Y : constant Entity_Id := Find_Overlaid_Object (N);
868 -- Exported variables cannot have an address clause,
869 -- because this cancels the effect of the pragma Export
871 if Is_Exported (U_Ent) then
873 ("cannot export object with address clause", Nam);
876 -- Overlaying controlled objects is erroneous
879 and then (Has_Controlled_Component (Etype (Aent))
880 or else Is_Controlled (Etype (Aent)))
883 ("?cannot overlay with controlled object", Expr);
885 ("\?Program_Error will be raised at run time", Expr);
886 Insert_Action (Declaration_Node (U_Ent),
887 Make_Raise_Program_Error (Loc,
888 Reason => PE_Overlaid_Controlled_Object));
892 and then Ekind (U_Ent) = E_Constant
893 and then Ekind (Aent) /= E_Constant
895 Error_Msg_N ("constant overlays a variable?", Expr);
897 elsif Present (Renamed_Object (U_Ent)) then
899 ("address clause not allowed"
900 & " for a renaming declaration (RM 13.1(6))", Nam);
903 -- Imported variables can have an address clause, but then
904 -- the import is pretty meaningless except to suppress
905 -- initializations, so we do not need such variables to
906 -- be statically allocated (and in fact it causes trouble
907 -- if the address clause is a local value).
909 elsif Is_Imported (U_Ent) then
910 Set_Is_Statically_Allocated (U_Ent, False);
913 -- We mark a possible modification of a variable with an
914 -- address clause, since it is likely aliasing is occurring.
916 Note_Possible_Modification (Nam, Sure => False);
918 -- Here we are checking for explicit overlap of one variable
919 -- by another, and if we find this then mark the overlapped
920 -- variable as also being volatile to prevent unwanted
923 if Present (Ent_Y) then
924 Set_Treat_As_Volatile (Ent_Y);
927 -- Legality checks on the address clause for initialized
928 -- objects is deferred until the freeze point, because
929 -- a subsequent pragma might indicate that the object is
930 -- imported and thus not initialized.
932 Set_Has_Delayed_Freeze (U_Ent);
934 if Is_Exported (U_Ent) then
936 ("& cannot be exported if an address clause is given",
939 ("\define and export a variable " &
940 "that holds its address instead",
944 -- Entity has delayed freeze, so we will generate an
945 -- alignment check at the freeze point unless suppressed.
947 if not Range_Checks_Suppressed (U_Ent)
948 and then not Alignment_Checks_Suppressed (U_Ent)
950 Set_Check_Address_Alignment (N);
953 -- Kill the size check code, since we are not allocating
954 -- the variable, it is somewhere else.
956 Kill_Size_Check_Code (U_Ent);
959 -- If the address clause is of the form:
961 -- for Y'Address use X'Address
965 -- Const : constant Address := X'Address;
967 -- for Y'Address use Const;
969 -- then we make an entry in the table for checking the size and
970 -- alignment of the overlaying variable. We defer this check
971 -- till after code generation to take full advantage of the
972 -- annotation done by the back end. This entry is only made if
973 -- we have not already posted a warning about size/alignment
974 -- (some warnings of this type are posted in Checks), and if
975 -- the address clause comes from source.
977 if Address_Clause_Overlay_Warnings
978 and then Comes_From_Source (N)
981 Ent_X : Entity_Id := Empty;
982 Ent_Y : Entity_Id := Empty;
985 Ent_Y := Find_Overlaid_Object (N);
987 if Present (Ent_Y) and then Is_Entity_Name (Name (N)) then
988 Ent_X := Entity (Name (N));
989 Address_Clause_Checks.Append ((N, Ent_X, Ent_Y));
991 -- If variable overlays a constant view, and we are
992 -- warning on overlays, then mark the variable as
993 -- overlaying a constant (we will give warnings later
994 -- if this variable is assigned).
996 if Is_Constant_Object (Ent_Y)
997 and then Ekind (Ent_X) = E_Variable
999 Set_Overlays_Constant (Ent_X);
1005 -- Not a valid entity for an address clause
1008 Error_Msg_N ("address cannot be given for &", Nam);
1016 -- Alignment attribute definition clause
1018 when Attribute_Alignment => Alignment_Block : declare
1019 Align : constant Uint := Get_Alignment_Value (Expr);
1024 if not Is_Type (U_Ent)
1025 and then Ekind (U_Ent) /= E_Variable
1026 and then Ekind (U_Ent) /= E_Constant
1028 Error_Msg_N ("alignment cannot be given for &", Nam);
1030 elsif Has_Alignment_Clause (U_Ent) then
1031 Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent));
1032 Error_Msg_N ("alignment clause previously given#", N);
1034 elsif Align /= No_Uint then
1035 Set_Has_Alignment_Clause (U_Ent);
1036 Set_Alignment (U_Ent, Align);
1038 end Alignment_Block;
1044 -- Bit_Order attribute definition clause
1046 when Attribute_Bit_Order => Bit_Order : declare
1048 if not Is_Record_Type (U_Ent) then
1050 ("Bit_Order can only be defined for record type", Nam);
1053 Analyze_And_Resolve (Expr, RTE (RE_Bit_Order));
1055 if Etype (Expr) = Any_Type then
1058 elsif not Is_Static_Expression (Expr) then
1059 Flag_Non_Static_Expr
1060 ("Bit_Order requires static expression!", Expr);
1063 if (Expr_Value (Expr) = 0) /= Bytes_Big_Endian then
1064 Set_Reverse_Bit_Order (U_Ent, True);
1070 --------------------
1071 -- Component_Size --
1072 --------------------
1074 -- Component_Size attribute definition clause
1076 when Attribute_Component_Size => Component_Size_Case : declare
1077 Csize : constant Uint := Static_Integer (Expr);
1080 New_Ctyp : Entity_Id;
1084 if not Is_Array_Type (U_Ent) then
1085 Error_Msg_N ("component size requires array type", Nam);
1089 Btype := Base_Type (U_Ent);
1091 if Has_Component_Size_Clause (Btype) then
1093 ("component size clause for& previously given", Nam);
1095 elsif Csize /= No_Uint then
1096 Check_Size (Expr, Component_Type (Btype), Csize, Biased);
1098 if Has_Aliased_Components (Btype)
1101 and then Csize /= 16
1104 ("component size incorrect for aliased components", N);
1108 -- For the biased case, build a declaration for a subtype
1109 -- that will be used to represent the biased subtype that
1110 -- reflects the biased representation of components. We need
1111 -- this subtype to get proper conversions on referencing
1112 -- elements of the array. Note that component size clauses
1113 -- are ignored in VM mode.
1115 if VM_Target = No_VM then
1118 Make_Defining_Identifier (Loc,
1120 New_External_Name (Chars (U_Ent), 'C', 0, 'T'));
1123 Make_Subtype_Declaration (Loc,
1124 Defining_Identifier => New_Ctyp,
1125 Subtype_Indication =>
1126 New_Occurrence_Of (Component_Type (Btype), Loc));
1128 Set_Parent (Decl, N);
1129 Analyze (Decl, Suppress => All_Checks);
1131 Set_Has_Delayed_Freeze (New_Ctyp, False);
1132 Set_Esize (New_Ctyp, Csize);
1133 Set_RM_Size (New_Ctyp, Csize);
1134 Init_Alignment (New_Ctyp);
1135 Set_Has_Biased_Representation (New_Ctyp, True);
1136 Set_Is_Itype (New_Ctyp, True);
1137 Set_Associated_Node_For_Itype (New_Ctyp, U_Ent);
1139 Set_Component_Type (Btype, New_Ctyp);
1141 if Warn_On_Biased_Representation then
1143 ("?component size clause forces biased "
1144 & "representation", N);
1148 Set_Component_Size (Btype, Csize);
1150 -- For VM case, we ignore component size clauses
1153 -- Give a warning unless we are in GNAT mode, in which case
1154 -- the warning is suppressed since it is not useful.
1156 if not GNAT_Mode then
1158 ("?component size ignored in this configuration", N);
1162 Set_Has_Component_Size_Clause (Btype, True);
1163 Set_Has_Non_Standard_Rep (Btype, True);
1165 end Component_Size_Case;
1171 when Attribute_External_Tag => External_Tag :
1173 if not Is_Tagged_Type (U_Ent) then
1174 Error_Msg_N ("should be a tagged type", Nam);
1177 Analyze_And_Resolve (Expr, Standard_String);
1179 if not Is_Static_Expression (Expr) then
1180 Flag_Non_Static_Expr
1181 ("static string required for tag name!", Nam);
1184 if VM_Target = No_VM then
1185 Set_Has_External_Tag_Rep_Clause (U_Ent);
1186 elsif not Inspector_Mode then
1187 Error_Msg_Name_1 := Attr;
1189 ("% attribute unsupported in this configuration", Nam);
1192 if not Is_Library_Level_Entity (U_Ent) then
1194 ("?non-unique external tag supplied for &", N, U_Ent);
1196 ("?\same external tag applies to all subprogram calls", N);
1198 ("?\corresponding internal tag cannot be obtained", N);
1206 when Attribute_Input =>
1207 Analyze_Stream_TSS_Definition (TSS_Stream_Input);
1208 Set_Has_Specified_Stream_Input (Ent);
1214 -- Machine radix attribute definition clause
1216 when Attribute_Machine_Radix => Machine_Radix : declare
1217 Radix : constant Uint := Static_Integer (Expr);
1220 if not Is_Decimal_Fixed_Point_Type (U_Ent) then
1221 Error_Msg_N ("decimal fixed-point type expected for &", Nam);
1223 elsif Has_Machine_Radix_Clause (U_Ent) then
1224 Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent));
1225 Error_Msg_N ("machine radix clause previously given#", N);
1227 elsif Radix /= No_Uint then
1228 Set_Has_Machine_Radix_Clause (U_Ent);
1229 Set_Has_Non_Standard_Rep (Base_Type (U_Ent));
1233 elsif Radix = 10 then
1234 Set_Machine_Radix_10 (U_Ent);
1236 Error_Msg_N ("machine radix value must be 2 or 10", Expr);
1245 -- Object_Size attribute definition clause
1247 when Attribute_Object_Size => Object_Size : declare
1248 Size : constant Uint := Static_Integer (Expr);
1251 pragma Warnings (Off, Biased);
1254 if not Is_Type (U_Ent) then
1255 Error_Msg_N ("Object_Size cannot be given for &", Nam);
1257 elsif Has_Object_Size_Clause (U_Ent) then
1258 Error_Msg_N ("Object_Size already given for &", Nam);
1261 Check_Size (Expr, U_Ent, Size, Biased);
1269 UI_Mod (Size, 64) /= 0
1272 ("Object_Size must be 8, 16, 32, or multiple of 64",
1276 Set_Esize (U_Ent, Size);
1277 Set_Has_Object_Size_Clause (U_Ent);
1278 Alignment_Check_For_Esize_Change (U_Ent);
1286 when Attribute_Output =>
1287 Analyze_Stream_TSS_Definition (TSS_Stream_Output);
1288 Set_Has_Specified_Stream_Output (Ent);
1294 when Attribute_Read =>
1295 Analyze_Stream_TSS_Definition (TSS_Stream_Read);
1296 Set_Has_Specified_Stream_Read (Ent);
1302 -- Size attribute definition clause
1304 when Attribute_Size => Size : declare
1305 Size : constant Uint := Static_Integer (Expr);
1312 if Has_Size_Clause (U_Ent) then
1313 Error_Msg_N ("size already given for &", Nam);
1315 elsif not Is_Type (U_Ent)
1316 and then Ekind (U_Ent) /= E_Variable
1317 and then Ekind (U_Ent) /= E_Constant
1319 Error_Msg_N ("size cannot be given for &", Nam);
1321 elsif Is_Array_Type (U_Ent)
1322 and then not Is_Constrained (U_Ent)
1325 ("size cannot be given for unconstrained array", Nam);
1327 elsif Size /= No_Uint then
1328 if Is_Type (U_Ent) then
1331 Etyp := Etype (U_Ent);
1334 -- Check size, note that Gigi is in charge of checking that the
1335 -- size of an array or record type is OK. Also we do not check
1336 -- the size in the ordinary fixed-point case, since it is too
1337 -- early to do so (there may be subsequent small clause that
1338 -- affects the size). We can check the size if a small clause
1339 -- has already been given.
1341 if not Is_Ordinary_Fixed_Point_Type (U_Ent)
1342 or else Has_Small_Clause (U_Ent)
1344 Check_Size (Expr, Etyp, Size, Biased);
1345 Set_Has_Biased_Representation (U_Ent, Biased);
1347 if Biased and Warn_On_Biased_Representation then
1349 ("?size clause forces biased representation", N);
1353 -- For types set RM_Size and Esize if possible
1355 if Is_Type (U_Ent) then
1356 Set_RM_Size (U_Ent, Size);
1358 -- For scalar types, increase Object_Size to power of 2, but
1359 -- not less than a storage unit in any case (i.e., normally
1360 -- this means it will be byte addressable).
1362 if Is_Scalar_Type (U_Ent) then
1363 if Size <= System_Storage_Unit then
1364 Init_Esize (U_Ent, System_Storage_Unit);
1365 elsif Size <= 16 then
1366 Init_Esize (U_Ent, 16);
1367 elsif Size <= 32 then
1368 Init_Esize (U_Ent, 32);
1370 Set_Esize (U_Ent, (Size + 63) / 64 * 64);
1373 -- For all other types, object size = value size. The
1374 -- backend will adjust as needed.
1377 Set_Esize (U_Ent, Size);
1380 Alignment_Check_For_Esize_Change (U_Ent);
1382 -- For objects, set Esize only
1385 if Is_Elementary_Type (Etyp) then
1386 if Size /= System_Storage_Unit
1388 Size /= System_Storage_Unit * 2
1390 Size /= System_Storage_Unit * 4
1392 Size /= System_Storage_Unit * 8
1394 Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit);
1395 Error_Msg_Uint_2 := Error_Msg_Uint_1 * 8;
1397 ("size for primitive object must be a power of 2"
1398 & " in the range ^-^", N);
1402 Set_Esize (U_Ent, Size);
1405 Set_Has_Size_Clause (U_Ent);
1413 -- Small attribute definition clause
1415 when Attribute_Small => Small : declare
1416 Implicit_Base : constant Entity_Id := Base_Type (U_Ent);
1420 Analyze_And_Resolve (Expr, Any_Real);
1422 if Etype (Expr) = Any_Type then
1425 elsif not Is_Static_Expression (Expr) then
1426 Flag_Non_Static_Expr
1427 ("small requires static expression!", Expr);
1431 Small := Expr_Value_R (Expr);
1433 if Small <= Ureal_0 then
1434 Error_Msg_N ("small value must be greater than zero", Expr);
1440 if not Is_Ordinary_Fixed_Point_Type (U_Ent) then
1442 ("small requires an ordinary fixed point type", Nam);
1444 elsif Has_Small_Clause (U_Ent) then
1445 Error_Msg_N ("small already given for &", Nam);
1447 elsif Small > Delta_Value (U_Ent) then
1449 ("small value must not be greater then delta value", Nam);
1452 Set_Small_Value (U_Ent, Small);
1453 Set_Small_Value (Implicit_Base, Small);
1454 Set_Has_Small_Clause (U_Ent);
1455 Set_Has_Small_Clause (Implicit_Base);
1456 Set_Has_Non_Standard_Rep (Implicit_Base);
1464 -- Storage_Pool attribute definition clause
1466 when Attribute_Storage_Pool => Storage_Pool : declare
1471 if Ekind (U_Ent) = E_Access_Subprogram_Type then
1473 ("storage pool cannot be given for access-to-subprogram type",
1477 elsif Ekind (U_Ent) /= E_Access_Type
1478 and then Ekind (U_Ent) /= E_General_Access_Type
1481 ("storage pool can only be given for access types", Nam);
1484 elsif Is_Derived_Type (U_Ent) then
1486 ("storage pool cannot be given for a derived access type",
1489 elsif Has_Storage_Size_Clause (U_Ent) then
1490 Error_Msg_N ("storage size already given for &", Nam);
1493 elsif Present (Associated_Storage_Pool (U_Ent)) then
1494 Error_Msg_N ("storage pool already given for &", Nam);
1499 (Expr, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
1501 if not Denotes_Variable (Expr) then
1502 Error_Msg_N ("storage pool must be a variable", Expr);
1506 if Nkind (Expr) = N_Type_Conversion then
1507 T := Etype (Expression (Expr));
1512 -- The Stack_Bounded_Pool is used internally for implementing
1513 -- access types with a Storage_Size. Since it only work
1514 -- properly when used on one specific type, we need to check
1515 -- that it is not hijacked improperly:
1516 -- type T is access Integer;
1517 -- for T'Storage_Size use n;
1518 -- type Q is access Float;
1519 -- for Q'Storage_Size use T'Storage_Size; -- incorrect
1521 if RTE_Available (RE_Stack_Bounded_Pool)
1522 and then Base_Type (T) = RTE (RE_Stack_Bounded_Pool)
1524 Error_Msg_N ("non-shareable internal Pool", Expr);
1528 -- If the argument is a name that is not an entity name, then
1529 -- we construct a renaming operation to define an entity of
1530 -- type storage pool.
1532 if not Is_Entity_Name (Expr)
1533 and then Is_Object_Reference (Expr)
1536 Make_Defining_Identifier (Loc,
1537 Chars => New_Internal_Name ('P'));
1540 Rnode : constant Node_Id :=
1541 Make_Object_Renaming_Declaration (Loc,
1542 Defining_Identifier => Pool,
1544 New_Occurrence_Of (Etype (Expr), Loc),
1548 Insert_Before (N, Rnode);
1550 Set_Associated_Storage_Pool (U_Ent, Pool);
1553 elsif Is_Entity_Name (Expr) then
1554 Pool := Entity (Expr);
1556 -- If pool is a renamed object, get original one. This can
1557 -- happen with an explicit renaming, and within instances.
1559 while Present (Renamed_Object (Pool))
1560 and then Is_Entity_Name (Renamed_Object (Pool))
1562 Pool := Entity (Renamed_Object (Pool));
1565 if Present (Renamed_Object (Pool))
1566 and then Nkind (Renamed_Object (Pool)) = N_Type_Conversion
1567 and then Is_Entity_Name (Expression (Renamed_Object (Pool)))
1569 Pool := Entity (Expression (Renamed_Object (Pool)));
1572 Set_Associated_Storage_Pool (U_Ent, Pool);
1574 elsif Nkind (Expr) = N_Type_Conversion
1575 and then Is_Entity_Name (Expression (Expr))
1576 and then Nkind (Original_Node (Expr)) = N_Attribute_Reference
1578 Pool := Entity (Expression (Expr));
1579 Set_Associated_Storage_Pool (U_Ent, Pool);
1582 Error_Msg_N ("incorrect reference to a Storage Pool", Expr);
1591 -- Storage_Size attribute definition clause
1593 when Attribute_Storage_Size => Storage_Size : declare
1594 Btype : constant Entity_Id := Base_Type (U_Ent);
1598 if Is_Task_Type (U_Ent) then
1599 Check_Restriction (No_Obsolescent_Features, N);
1601 if Warn_On_Obsolescent_Feature then
1603 ("storage size clause for task is an " &
1604 "obsolescent feature (RM J.9)?", N);
1606 ("\use Storage_Size pragma instead?", N);
1612 if not Is_Access_Type (U_Ent)
1613 and then Ekind (U_Ent) /= E_Task_Type
1615 Error_Msg_N ("storage size cannot be given for &", Nam);
1617 elsif Is_Access_Type (U_Ent) and Is_Derived_Type (U_Ent) then
1619 ("storage size cannot be given for a derived access type",
1622 elsif Has_Storage_Size_Clause (Btype) then
1623 Error_Msg_N ("storage size already given for &", Nam);
1626 Analyze_And_Resolve (Expr, Any_Integer);
1628 if Is_Access_Type (U_Ent) then
1629 if Present (Associated_Storage_Pool (U_Ent)) then
1630 Error_Msg_N ("storage pool already given for &", Nam);
1634 if Compile_Time_Known_Value (Expr)
1635 and then Expr_Value (Expr) = 0
1637 Set_No_Pool_Assigned (Btype);
1640 else -- Is_Task_Type (U_Ent)
1641 Sprag := Get_Rep_Pragma (Btype, Name_Storage_Size);
1643 if Present (Sprag) then
1644 Error_Msg_Sloc := Sloc (Sprag);
1646 ("Storage_Size already specified#", Nam);
1651 Set_Has_Storage_Size_Clause (Btype);
1659 when Attribute_Stream_Size => Stream_Size : declare
1660 Size : constant Uint := Static_Integer (Expr);
1663 if Ada_Version <= Ada_95 then
1664 Check_Restriction (No_Implementation_Attributes, N);
1667 if Has_Stream_Size_Clause (U_Ent) then
1668 Error_Msg_N ("Stream_Size already given for &", Nam);
1670 elsif Is_Elementary_Type (U_Ent) then
1671 if Size /= System_Storage_Unit
1673 Size /= System_Storage_Unit * 2
1675 Size /= System_Storage_Unit * 4
1677 Size /= System_Storage_Unit * 8
1679 Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit);
1681 ("stream size for elementary type must be a"
1682 & " power of 2 and at least ^", N);
1684 elsif RM_Size (U_Ent) > Size then
1685 Error_Msg_Uint_1 := RM_Size (U_Ent);
1687 ("stream size for elementary type must be a"
1688 & " power of 2 and at least ^", N);
1691 Set_Has_Stream_Size_Clause (U_Ent);
1694 Error_Msg_N ("Stream_Size cannot be given for &", Nam);
1702 -- Value_Size attribute definition clause
1704 when Attribute_Value_Size => Value_Size : declare
1705 Size : constant Uint := Static_Integer (Expr);
1709 if not Is_Type (U_Ent) then
1710 Error_Msg_N ("Value_Size cannot be given for &", Nam);
1713 (Get_Attribute_Definition_Clause
1714 (U_Ent, Attribute_Value_Size))
1716 Error_Msg_N ("Value_Size already given for &", Nam);
1718 elsif Is_Array_Type (U_Ent)
1719 and then not Is_Constrained (U_Ent)
1722 ("Value_Size cannot be given for unconstrained array", Nam);
1725 if Is_Elementary_Type (U_Ent) then
1726 Check_Size (Expr, U_Ent, Size, Biased);
1727 Set_Has_Biased_Representation (U_Ent, Biased);
1729 if Biased and Warn_On_Biased_Representation then
1731 ("?value size clause forces biased representation", N);
1735 Set_RM_Size (U_Ent, Size);
1743 when Attribute_Write =>
1744 Analyze_Stream_TSS_Definition (TSS_Stream_Write);
1745 Set_Has_Specified_Stream_Write (Ent);
1747 -- All other attributes cannot be set
1751 ("attribute& cannot be set with definition clause", N);
1754 -- The test for the type being frozen must be performed after
1755 -- any expression the clause has been analyzed since the expression
1756 -- itself might cause freezing that makes the clause illegal.
1758 if Rep_Item_Too_Late (U_Ent, N, FOnly) then
1761 end Analyze_Attribute_Definition_Clause;
1763 ----------------------------
1764 -- Analyze_Code_Statement --
1765 ----------------------------
1767 procedure Analyze_Code_Statement (N : Node_Id) is
1768 HSS : constant Node_Id := Parent (N);
1769 SBody : constant Node_Id := Parent (HSS);
1770 Subp : constant Entity_Id := Current_Scope;
1777 -- Analyze and check we get right type, note that this implements the
1778 -- requirement (RM 13.8(1)) that Machine_Code be with'ed, since that
1779 -- is the only way that Asm_Insn could possibly be visible.
1781 Analyze_And_Resolve (Expression (N));
1783 if Etype (Expression (N)) = Any_Type then
1785 elsif Etype (Expression (N)) /= RTE (RE_Asm_Insn) then
1786 Error_Msg_N ("incorrect type for code statement", N);
1790 Check_Code_Statement (N);
1792 -- Make sure we appear in the handled statement sequence of a
1793 -- subprogram (RM 13.8(3)).
1795 if Nkind (HSS) /= N_Handled_Sequence_Of_Statements
1796 or else Nkind (SBody) /= N_Subprogram_Body
1799 ("code statement can only appear in body of subprogram", N);
1803 -- Do remaining checks (RM 13.8(3)) if not already done
1805 if not Is_Machine_Code_Subprogram (Subp) then
1806 Set_Is_Machine_Code_Subprogram (Subp);
1808 -- No exception handlers allowed
1810 if Present (Exception_Handlers (HSS)) then
1812 ("exception handlers not permitted in machine code subprogram",
1813 First (Exception_Handlers (HSS)));
1816 -- No declarations other than use clauses and pragmas (we allow
1817 -- certain internally generated declarations as well).
1819 Decl := First (Declarations (SBody));
1820 while Present (Decl) loop
1821 DeclO := Original_Node (Decl);
1822 if Comes_From_Source (DeclO)
1823 and not Nkind_In (DeclO, N_Pragma,
1824 N_Use_Package_Clause,
1826 N_Implicit_Label_Declaration)
1829 ("this declaration not allowed in machine code subprogram",
1836 -- No statements other than code statements, pragmas, and labels.
1837 -- Again we allow certain internally generated statements.
1839 Stmt := First (Statements (HSS));
1840 while Present (Stmt) loop
1841 StmtO := Original_Node (Stmt);
1842 if Comes_From_Source (StmtO)
1843 and then not Nkind_In (StmtO, N_Pragma,
1848 ("this statement is not allowed in machine code subprogram",
1855 end Analyze_Code_Statement;
1857 -----------------------------------------------
1858 -- Analyze_Enumeration_Representation_Clause --
1859 -----------------------------------------------
1861 procedure Analyze_Enumeration_Representation_Clause (N : Node_Id) is
1862 Ident : constant Node_Id := Identifier (N);
1863 Aggr : constant Node_Id := Array_Aggregate (N);
1864 Enumtype : Entity_Id;
1870 Err : Boolean := False;
1872 Lo : constant Uint := Expr_Value (Type_Low_Bound (Universal_Integer));
1873 Hi : constant Uint := Expr_Value (Type_High_Bound (Universal_Integer));
1878 if Ignore_Rep_Clauses then
1882 -- First some basic error checks
1885 Enumtype := Entity (Ident);
1887 if Enumtype = Any_Type
1888 or else Rep_Item_Too_Early (Enumtype, N)
1892 Enumtype := Underlying_Type (Enumtype);
1895 if not Is_Enumeration_Type (Enumtype) then
1897 ("enumeration type required, found}",
1898 Ident, First_Subtype (Enumtype));
1902 -- Ignore rep clause on generic actual type. This will already have
1903 -- been flagged on the template as an error, and this is the safest
1904 -- way to ensure we don't get a junk cascaded message in the instance.
1906 if Is_Generic_Actual_Type (Enumtype) then
1909 -- Type must be in current scope
1911 elsif Scope (Enumtype) /= Current_Scope then
1912 Error_Msg_N ("type must be declared in this scope", Ident);
1915 -- Type must be a first subtype
1917 elsif not Is_First_Subtype (Enumtype) then
1918 Error_Msg_N ("cannot give enumeration rep clause for subtype", N);
1921 -- Ignore duplicate rep clause
1923 elsif Has_Enumeration_Rep_Clause (Enumtype) then
1924 Error_Msg_N ("duplicate enumeration rep clause ignored", N);
1927 -- Don't allow rep clause for standard [wide_[wide_]]character
1929 elsif Is_Standard_Character_Type (Enumtype) then
1930 Error_Msg_N ("enumeration rep clause not allowed for this type", N);
1933 -- Check that the expression is a proper aggregate (no parentheses)
1935 elsif Paren_Count (Aggr) /= 0 then
1937 ("extra parentheses surrounding aggregate not allowed",
1941 -- All tests passed, so set rep clause in place
1944 Set_Has_Enumeration_Rep_Clause (Enumtype);
1945 Set_Has_Enumeration_Rep_Clause (Base_Type (Enumtype));
1948 -- Now we process the aggregate. Note that we don't use the normal
1949 -- aggregate code for this purpose, because we don't want any of the
1950 -- normal expansion activities, and a number of special semantic
1951 -- rules apply (including the component type being any integer type)
1953 Elit := First_Literal (Enumtype);
1955 -- First the positional entries if any
1957 if Present (Expressions (Aggr)) then
1958 Expr := First (Expressions (Aggr));
1959 while Present (Expr) loop
1961 Error_Msg_N ("too many entries in aggregate", Expr);
1965 Val := Static_Integer (Expr);
1967 -- Err signals that we found some incorrect entries processing
1968 -- the list. The final checks for completeness and ordering are
1969 -- skipped in this case.
1971 if Val = No_Uint then
1973 elsif Val < Lo or else Hi < Val then
1974 Error_Msg_N ("value outside permitted range", Expr);
1978 Set_Enumeration_Rep (Elit, Val);
1979 Set_Enumeration_Rep_Expr (Elit, Expr);
1985 -- Now process the named entries if present
1987 if Present (Component_Associations (Aggr)) then
1988 Assoc := First (Component_Associations (Aggr));
1989 while Present (Assoc) loop
1990 Choice := First (Choices (Assoc));
1992 if Present (Next (Choice)) then
1994 ("multiple choice not allowed here", Next (Choice));
1998 if Nkind (Choice) = N_Others_Choice then
1999 Error_Msg_N ("others choice not allowed here", Choice);
2002 elsif Nkind (Choice) = N_Range then
2003 -- ??? should allow zero/one element range here
2004 Error_Msg_N ("range not allowed here", Choice);
2008 Analyze_And_Resolve (Choice, Enumtype);
2010 if Is_Entity_Name (Choice)
2011 and then Is_Type (Entity (Choice))
2013 Error_Msg_N ("subtype name not allowed here", Choice);
2015 -- ??? should allow static subtype with zero/one entry
2017 elsif Etype (Choice) = Base_Type (Enumtype) then
2018 if not Is_Static_Expression (Choice) then
2019 Flag_Non_Static_Expr
2020 ("non-static expression used for choice!", Choice);
2024 Elit := Expr_Value_E (Choice);
2026 if Present (Enumeration_Rep_Expr (Elit)) then
2027 Error_Msg_Sloc := Sloc (Enumeration_Rep_Expr (Elit));
2029 ("representation for& previously given#",
2034 Set_Enumeration_Rep_Expr (Elit, Choice);
2036 Expr := Expression (Assoc);
2037 Val := Static_Integer (Expr);
2039 if Val = No_Uint then
2042 elsif Val < Lo or else Hi < Val then
2043 Error_Msg_N ("value outside permitted range", Expr);
2047 Set_Enumeration_Rep (Elit, Val);
2056 -- Aggregate is fully processed. Now we check that a full set of
2057 -- representations was given, and that they are in range and in order.
2058 -- These checks are only done if no other errors occurred.
2064 Elit := First_Literal (Enumtype);
2065 while Present (Elit) loop
2066 if No (Enumeration_Rep_Expr (Elit)) then
2067 Error_Msg_NE ("missing representation for&!", N, Elit);
2070 Val := Enumeration_Rep (Elit);
2072 if Min = No_Uint then
2076 if Val /= No_Uint then
2077 if Max /= No_Uint and then Val <= Max then
2079 ("enumeration value for& not ordered!",
2080 Enumeration_Rep_Expr (Elit), Elit);
2086 -- If there is at least one literal whose representation
2087 -- is not equal to the Pos value, then note that this
2088 -- enumeration type has a non-standard representation.
2090 if Val /= Enumeration_Pos (Elit) then
2091 Set_Has_Non_Standard_Rep (Base_Type (Enumtype));
2098 -- Now set proper size information
2101 Minsize : Uint := UI_From_Int (Minimum_Size (Enumtype));
2104 if Has_Size_Clause (Enumtype) then
2105 if Esize (Enumtype) >= Minsize then
2110 UI_From_Int (Minimum_Size (Enumtype, Biased => True));
2112 if Esize (Enumtype) < Minsize then
2113 Error_Msg_N ("previously given size is too small", N);
2116 Set_Has_Biased_Representation (Enumtype);
2121 Set_RM_Size (Enumtype, Minsize);
2122 Set_Enum_Esize (Enumtype);
2125 Set_RM_Size (Base_Type (Enumtype), RM_Size (Enumtype));
2126 Set_Esize (Base_Type (Enumtype), Esize (Enumtype));
2127 Set_Alignment (Base_Type (Enumtype), Alignment (Enumtype));
2131 -- We repeat the too late test in case it froze itself!
2133 if Rep_Item_Too_Late (Enumtype, N) then
2136 end Analyze_Enumeration_Representation_Clause;
2138 ----------------------------
2139 -- Analyze_Free_Statement --
2140 ----------------------------
2142 procedure Analyze_Free_Statement (N : Node_Id) is
2144 Analyze (Expression (N));
2145 end Analyze_Free_Statement;
2147 ------------------------------------------
2148 -- Analyze_Record_Representation_Clause --
2149 ------------------------------------------
2151 procedure Analyze_Record_Representation_Clause (N : Node_Id) is
2152 Loc : constant Source_Ptr := Sloc (N);
2153 Ident : constant Node_Id := Identifier (N);
2154 Rectype : Entity_Id;
2160 Hbit : Uint := Uint_0;
2165 Max_Bit_So_Far : Uint;
2166 -- Records the maximum bit position so far. If all field positions
2167 -- are monotonically increasing, then we can skip the circuit for
2168 -- checking for overlap, since no overlap is possible.
2170 Overlap_Check_Required : Boolean;
2171 -- Used to keep track of whether or not an overlap check is required
2173 Ccount : Natural := 0;
2174 -- Number of component clauses in record rep clause
2176 CR_Pragma : Node_Id := Empty;
2177 -- Points to N_Pragma node if Complete_Representation pragma present
2180 if Ignore_Rep_Clauses then
2185 Rectype := Entity (Ident);
2187 if Rectype = Any_Type
2188 or else Rep_Item_Too_Early (Rectype, N)
2192 Rectype := Underlying_Type (Rectype);
2195 -- First some basic error checks
2197 if not Is_Record_Type (Rectype) then
2199 ("record type required, found}", Ident, First_Subtype (Rectype));
2202 elsif Is_Unchecked_Union (Rectype) then
2204 ("record rep clause not allowed for Unchecked_Union", N);
2206 elsif Scope (Rectype) /= Current_Scope then
2207 Error_Msg_N ("type must be declared in this scope", N);
2210 elsif not Is_First_Subtype (Rectype) then
2211 Error_Msg_N ("cannot give record rep clause for subtype", N);
2214 elsif Has_Record_Rep_Clause (Rectype) then
2215 Error_Msg_N ("duplicate record rep clause ignored", N);
2218 elsif Rep_Item_Too_Late (Rectype, N) then
2222 if Present (Mod_Clause (N)) then
2224 Loc : constant Source_Ptr := Sloc (N);
2225 M : constant Node_Id := Mod_Clause (N);
2226 P : constant List_Id := Pragmas_Before (M);
2230 pragma Warnings (Off, Mod_Val);
2233 Check_Restriction (No_Obsolescent_Features, Mod_Clause (N));
2235 if Warn_On_Obsolescent_Feature then
2237 ("mod clause is an obsolescent feature (RM J.8)?", N);
2239 ("\use alignment attribute definition clause instead?", N);
2246 -- In ASIS_Mode mode, expansion is disabled, but we must convert
2247 -- the Mod clause into an alignment clause anyway, so that the
2248 -- back-end can compute and back-annotate properly the size and
2249 -- alignment of types that may include this record.
2251 -- This seems dubious, this destroys the source tree in a manner
2252 -- not detectable by ASIS ???
2254 if Operating_Mode = Check_Semantics
2258 Make_Attribute_Definition_Clause (Loc,
2259 Name => New_Reference_To (Base_Type (Rectype), Loc),
2260 Chars => Name_Alignment,
2261 Expression => Relocate_Node (Expression (M)));
2263 Set_From_At_Mod (AtM_Nod);
2264 Insert_After (N, AtM_Nod);
2265 Mod_Val := Get_Alignment_Value (Expression (AtM_Nod));
2266 Set_Mod_Clause (N, Empty);
2269 -- Get the alignment value to perform error checking
2271 Mod_Val := Get_Alignment_Value (Expression (M));
2277 -- For untagged types, clear any existing component clauses for the
2278 -- type. If the type is derived, this is what allows us to override
2279 -- a rep clause for the parent. For type extensions, the representation
2280 -- of the inherited components is inherited, so we want to keep previous
2281 -- component clauses for completeness.
2283 if not Is_Tagged_Type (Rectype) then
2284 Comp := First_Component_Or_Discriminant (Rectype);
2285 while Present (Comp) loop
2286 Set_Component_Clause (Comp, Empty);
2287 Next_Component_Or_Discriminant (Comp);
2291 -- All done if no component clauses
2293 CC := First (Component_Clauses (N));
2299 -- If a tag is present, then create a component clause that places it
2300 -- at the start of the record (otherwise gigi may place it after other
2301 -- fields that have rep clauses).
2303 Fent := First_Entity (Rectype);
2305 if Nkind (Fent) = N_Defining_Identifier
2306 and then Chars (Fent) = Name_uTag
2308 Set_Component_Bit_Offset (Fent, Uint_0);
2309 Set_Normalized_Position (Fent, Uint_0);
2310 Set_Normalized_First_Bit (Fent, Uint_0);
2311 Set_Normalized_Position_Max (Fent, Uint_0);
2312 Init_Esize (Fent, System_Address_Size);
2314 Set_Component_Clause (Fent,
2315 Make_Component_Clause (Loc,
2317 Make_Identifier (Loc,
2318 Chars => Name_uTag),
2321 Make_Integer_Literal (Loc,
2325 Make_Integer_Literal (Loc,
2329 Make_Integer_Literal (Loc,
2330 UI_From_Int (System_Address_Size))));
2332 Ccount := Ccount + 1;
2335 -- A representation like this applies to the base type
2337 Set_Has_Record_Rep_Clause (Base_Type (Rectype));
2338 Set_Has_Non_Standard_Rep (Base_Type (Rectype));
2339 Set_Has_Specified_Layout (Base_Type (Rectype));
2341 Max_Bit_So_Far := Uint_Minus_1;
2342 Overlap_Check_Required := False;
2344 -- Process the component clauses
2346 while Present (CC) loop
2350 if Nkind (CC) = N_Pragma then
2353 -- The only pragma of interest is Complete_Representation
2355 if Pragma_Name (CC) = Name_Complete_Representation then
2359 -- Processing for real component clause
2362 Ccount := Ccount + 1;
2363 Posit := Static_Integer (Position (CC));
2364 Fbit := Static_Integer (First_Bit (CC));
2365 Lbit := Static_Integer (Last_Bit (CC));
2368 and then Fbit /= No_Uint
2369 and then Lbit /= No_Uint
2373 ("position cannot be negative", Position (CC));
2377 ("first bit cannot be negative", First_Bit (CC));
2379 -- The Last_Bit specified in a component clause must not be
2380 -- less than the First_Bit minus one (RM-13.5.1(10)).
2382 elsif Lbit < Fbit - 1 then
2384 ("last bit cannot be less than first bit minus one",
2387 -- Values look OK, so find the corresponding record component
2388 -- Even though the syntax allows an attribute reference for
2389 -- implementation-defined components, GNAT does not allow the
2390 -- tag to get an explicit position.
2392 elsif Nkind (Component_Name (CC)) = N_Attribute_Reference then
2393 if Attribute_Name (Component_Name (CC)) = Name_Tag then
2394 Error_Msg_N ("position of tag cannot be specified", CC);
2396 Error_Msg_N ("illegal component name", CC);
2400 Comp := First_Entity (Rectype);
2401 while Present (Comp) loop
2402 exit when Chars (Comp) = Chars (Component_Name (CC));
2408 -- Maybe component of base type that is absent from
2409 -- statically constrained first subtype.
2411 Comp := First_Entity (Base_Type (Rectype));
2412 while Present (Comp) loop
2413 exit when Chars (Comp) = Chars (Component_Name (CC));
2420 ("component clause is for non-existent field", CC);
2422 elsif Present (Component_Clause (Comp)) then
2424 -- Diagnose duplicate rep clause, or check consistency
2425 -- if this is an inherited component. In a double fault,
2426 -- there may be a duplicate inconsistent clause for an
2427 -- inherited component.
2429 if Scope (Original_Record_Component (Comp)) = Rectype
2430 or else Parent (Component_Clause (Comp)) = N
2432 Error_Msg_Sloc := Sloc (Component_Clause (Comp));
2433 Error_Msg_N ("component clause previously given#", CC);
2437 Rep1 : constant Node_Id := Component_Clause (Comp);
2439 if Intval (Position (Rep1)) /=
2440 Intval (Position (CC))
2441 or else Intval (First_Bit (Rep1)) /=
2442 Intval (First_Bit (CC))
2443 or else Intval (Last_Bit (Rep1)) /=
2444 Intval (Last_Bit (CC))
2446 Error_Msg_N ("component clause inconsistent "
2447 & "with representation of ancestor", CC);
2448 elsif Warn_On_Redundant_Constructs then
2449 Error_Msg_N ("?redundant component clause "
2450 & "for inherited component!", CC);
2456 -- Make reference for field in record rep clause and set
2457 -- appropriate entity field in the field identifier.
2460 (Comp, Component_Name (CC), Set_Ref => False);
2461 Set_Entity (Component_Name (CC), Comp);
2463 -- Update Fbit and Lbit to the actual bit number
2465 Fbit := Fbit + UI_From_Int (SSU) * Posit;
2466 Lbit := Lbit + UI_From_Int (SSU) * Posit;
2468 if Fbit <= Max_Bit_So_Far then
2469 Overlap_Check_Required := True;
2471 Max_Bit_So_Far := Lbit;
2474 if Has_Size_Clause (Rectype)
2475 and then Esize (Rectype) <= Lbit
2478 ("bit number out of range of specified size",
2481 Set_Component_Clause (Comp, CC);
2482 Set_Component_Bit_Offset (Comp, Fbit);
2483 Set_Esize (Comp, 1 + (Lbit - Fbit));
2484 Set_Normalized_First_Bit (Comp, Fbit mod SSU);
2485 Set_Normalized_Position (Comp, Fbit / SSU);
2487 Set_Normalized_Position_Max
2488 (Fent, Normalized_Position (Fent));
2490 if Is_Tagged_Type (Rectype)
2491 and then Fbit < System_Address_Size
2494 ("component overlaps tag field of&",
2498 -- This information is also set in the corresponding
2499 -- component of the base type, found by accessing the
2500 -- Original_Record_Component link if it is present.
2502 Ocomp := Original_Record_Component (Comp);
2509 (Component_Name (CC),
2514 Set_Has_Biased_Representation (Comp, Biased);
2516 if Biased and Warn_On_Biased_Representation then
2518 ("?component clause forces biased "
2519 & "representation", CC);
2522 if Present (Ocomp) then
2523 Set_Component_Clause (Ocomp, CC);
2524 Set_Component_Bit_Offset (Ocomp, Fbit);
2525 Set_Normalized_First_Bit (Ocomp, Fbit mod SSU);
2526 Set_Normalized_Position (Ocomp, Fbit / SSU);
2527 Set_Esize (Ocomp, 1 + (Lbit - Fbit));
2529 Set_Normalized_Position_Max
2530 (Ocomp, Normalized_Position (Ocomp));
2532 Set_Has_Biased_Representation
2533 (Ocomp, Has_Biased_Representation (Comp));
2536 if Esize (Comp) < 0 then
2537 Error_Msg_N ("component size is negative", CC);
2548 -- Now that we have processed all the component clauses, check for
2549 -- overlap. We have to leave this till last, since the components can
2550 -- appear in any arbitrary order in the representation clause.
2552 -- We do not need this check if all specified ranges were monotonic,
2553 -- as recorded by Overlap_Check_Required being False at this stage.
2555 -- This first section checks if there are any overlapping entries at
2556 -- all. It does this by sorting all entries and then seeing if there are
2557 -- any overlaps. If there are none, then that is decisive, but if there
2558 -- are overlaps, they may still be OK (they may result from fields in
2559 -- different variants).
2561 if Overlap_Check_Required then
2562 Overlap_Check1 : declare
2564 OC_Fbit : array (0 .. Ccount) of Uint;
2565 -- First-bit values for component clauses, the value is the offset
2566 -- of the first bit of the field from start of record. The zero
2567 -- entry is for use in sorting.
2569 OC_Lbit : array (0 .. Ccount) of Uint;
2570 -- Last-bit values for component clauses, the value is the offset
2571 -- of the last bit of the field from start of record. The zero
2572 -- entry is for use in sorting.
2574 OC_Count : Natural := 0;
2575 -- Count of entries in OC_Fbit and OC_Lbit
2577 function OC_Lt (Op1, Op2 : Natural) return Boolean;
2578 -- Compare routine for Sort
2580 procedure OC_Move (From : Natural; To : Natural);
2581 -- Move routine for Sort
2583 package Sorting is new GNAT.Heap_Sort_G (OC_Move, OC_Lt);
2585 function OC_Lt (Op1, Op2 : Natural) return Boolean is
2587 return OC_Fbit (Op1) < OC_Fbit (Op2);
2590 procedure OC_Move (From : Natural; To : Natural) is
2592 OC_Fbit (To) := OC_Fbit (From);
2593 OC_Lbit (To) := OC_Lbit (From);
2597 CC := First (Component_Clauses (N));
2598 while Present (CC) loop
2599 if Nkind (CC) /= N_Pragma then
2600 Posit := Static_Integer (Position (CC));
2601 Fbit := Static_Integer (First_Bit (CC));
2602 Lbit := Static_Integer (Last_Bit (CC));
2605 and then Fbit /= No_Uint
2606 and then Lbit /= No_Uint
2608 OC_Count := OC_Count + 1;
2609 Posit := Posit * SSU;
2610 OC_Fbit (OC_Count) := Fbit + Posit;
2611 OC_Lbit (OC_Count) := Lbit + Posit;
2618 Sorting.Sort (OC_Count);
2620 Overlap_Check_Required := False;
2621 for J in 1 .. OC_Count - 1 loop
2622 if OC_Lbit (J) >= OC_Fbit (J + 1) then
2623 Overlap_Check_Required := True;
2630 -- If Overlap_Check_Required is still True, then we have to do the full
2631 -- scale overlap check, since we have at least two fields that do
2632 -- overlap, and we need to know if that is OK since they are in
2633 -- different variant, or whether we have a definite problem.
2635 if Overlap_Check_Required then
2636 Overlap_Check2 : declare
2637 C1_Ent, C2_Ent : Entity_Id;
2638 -- Entities of components being checked for overlap
2641 -- Component_List node whose Component_Items are being checked
2644 -- Component declaration for component being checked
2647 C1_Ent := First_Entity (Base_Type (Rectype));
2649 -- Loop through all components in record. For each component check
2650 -- for overlap with any of the preceding elements on the component
2651 -- list containing the component and also, if the component is in
2652 -- a variant, check against components outside the case structure.
2653 -- This latter test is repeated recursively up the variant tree.
2655 Main_Component_Loop : while Present (C1_Ent) loop
2656 if Ekind (C1_Ent) /= E_Component
2657 and then Ekind (C1_Ent) /= E_Discriminant
2659 goto Continue_Main_Component_Loop;
2662 -- Skip overlap check if entity has no declaration node. This
2663 -- happens with discriminants in constrained derived types.
2664 -- Probably we are missing some checks as a result, but that
2665 -- does not seem terribly serious ???
2667 if No (Declaration_Node (C1_Ent)) then
2668 goto Continue_Main_Component_Loop;
2671 Clist := Parent (List_Containing (Declaration_Node (C1_Ent)));
2673 -- Loop through component lists that need checking. Check the
2674 -- current component list and all lists in variants above us.
2676 Component_List_Loop : loop
2678 -- If derived type definition, go to full declaration
2679 -- If at outer level, check discriminants if there are any.
2681 if Nkind (Clist) = N_Derived_Type_Definition then
2682 Clist := Parent (Clist);
2685 -- Outer level of record definition, check discriminants
2687 if Nkind_In (Clist, N_Full_Type_Declaration,
2688 N_Private_Type_Declaration)
2690 if Has_Discriminants (Defining_Identifier (Clist)) then
2692 First_Discriminant (Defining_Identifier (Clist));
2694 while Present (C2_Ent) loop
2695 exit when C1_Ent = C2_Ent;
2696 Check_Component_Overlap (C1_Ent, C2_Ent);
2697 Next_Discriminant (C2_Ent);
2701 -- Record extension case
2703 elsif Nkind (Clist) = N_Derived_Type_Definition then
2706 -- Otherwise check one component list
2709 Citem := First (Component_Items (Clist));
2711 while Present (Citem) loop
2712 if Nkind (Citem) = N_Component_Declaration then
2713 C2_Ent := Defining_Identifier (Citem);
2714 exit when C1_Ent = C2_Ent;
2715 Check_Component_Overlap (C1_Ent, C2_Ent);
2722 -- Check for variants above us (the parent of the Clist can
2723 -- be a variant, in which case its parent is a variant part,
2724 -- and the parent of the variant part is a component list
2725 -- whose components must all be checked against the current
2726 -- component for overlap).
2728 if Nkind (Parent (Clist)) = N_Variant then
2729 Clist := Parent (Parent (Parent (Clist)));
2731 -- Check for possible discriminant part in record, this is
2732 -- treated essentially as another level in the recursion.
2733 -- For this case the parent of the component list is the
2734 -- record definition, and its parent is the full type
2735 -- declaration containing the discriminant specifications.
2737 elsif Nkind (Parent (Clist)) = N_Record_Definition then
2738 Clist := Parent (Parent ((Clist)));
2740 -- If neither of these two cases, we are at the top of
2744 exit Component_List_Loop;
2746 end loop Component_List_Loop;
2748 <<Continue_Main_Component_Loop>>
2749 Next_Entity (C1_Ent);
2751 end loop Main_Component_Loop;
2755 -- For records that have component clauses for all components, and whose
2756 -- size is less than or equal to 32, we need to know the size in the
2757 -- front end to activate possible packed array processing where the
2758 -- component type is a record.
2760 -- At this stage Hbit + 1 represents the first unused bit from all the
2761 -- component clauses processed, so if the component clauses are
2762 -- complete, then this is the length of the record.
2764 -- For records longer than System.Storage_Unit, and for those where not
2765 -- all components have component clauses, the back end determines the
2766 -- length (it may for example be appropriate to round up the size
2767 -- to some convenient boundary, based on alignment considerations, etc).
2769 if Unknown_RM_Size (Rectype) and then Hbit + 1 <= 32 then
2771 -- Nothing to do if at least one component has no component clause
2773 Comp := First_Component_Or_Discriminant (Rectype);
2774 while Present (Comp) loop
2775 exit when No (Component_Clause (Comp));
2776 Next_Component_Or_Discriminant (Comp);
2779 -- If we fall out of loop, all components have component clauses
2780 -- and so we can set the size to the maximum value.
2783 Set_RM_Size (Rectype, Hbit + 1);
2787 -- Check missing components if Complete_Representation pragma appeared
2789 if Present (CR_Pragma) then
2790 Comp := First_Component_Or_Discriminant (Rectype);
2791 while Present (Comp) loop
2792 if No (Component_Clause (Comp)) then
2794 ("missing component clause for &", CR_Pragma, Comp);
2797 Next_Component_Or_Discriminant (Comp);
2800 -- If no Complete_Representation pragma, warn if missing components
2802 elsif Warn_On_Unrepped_Components then
2804 Num_Repped_Components : Nat := 0;
2805 Num_Unrepped_Components : Nat := 0;
2808 -- First count number of repped and unrepped components
2810 Comp := First_Component_Or_Discriminant (Rectype);
2811 while Present (Comp) loop
2812 if Present (Component_Clause (Comp)) then
2813 Num_Repped_Components := Num_Repped_Components + 1;
2815 Num_Unrepped_Components := Num_Unrepped_Components + 1;
2818 Next_Component_Or_Discriminant (Comp);
2821 -- We are only interested in the case where there is at least one
2822 -- unrepped component, and at least half the components have rep
2823 -- clauses. We figure that if less than half have them, then the
2824 -- partial rep clause is really intentional. If the component
2825 -- type has no underlying type set at this point (as for a generic
2826 -- formal type), we don't know enough to give a warning on the
2829 if Num_Unrepped_Components > 0
2830 and then Num_Unrepped_Components < Num_Repped_Components
2832 Comp := First_Component_Or_Discriminant (Rectype);
2833 while Present (Comp) loop
2834 if No (Component_Clause (Comp))
2835 and then Comes_From_Source (Comp)
2836 and then Present (Underlying_Type (Etype (Comp)))
2837 and then (Is_Scalar_Type (Underlying_Type (Etype (Comp)))
2838 or else Size_Known_At_Compile_Time
2839 (Underlying_Type (Etype (Comp))))
2840 and then not Has_Warnings_Off (Rectype)
2842 Error_Msg_Sloc := Sloc (Comp);
2844 ("?no component clause given for & declared #",
2848 Next_Component_Or_Discriminant (Comp);
2853 end Analyze_Record_Representation_Clause;
2855 -----------------------------
2856 -- Check_Component_Overlap --
2857 -----------------------------
2859 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id) is
2861 if Present (Component_Clause (C1_Ent))
2862 and then Present (Component_Clause (C2_Ent))
2864 -- Exclude odd case where we have two tag fields in the same record,
2865 -- both at location zero. This seems a bit strange, but it seems to
2866 -- happen in some circumstances ???
2868 if Chars (C1_Ent) = Name_uTag
2869 and then Chars (C2_Ent) = Name_uTag
2874 -- Here we check if the two fields overlap
2877 S1 : constant Uint := Component_Bit_Offset (C1_Ent);
2878 S2 : constant Uint := Component_Bit_Offset (C2_Ent);
2879 E1 : constant Uint := S1 + Esize (C1_Ent);
2880 E2 : constant Uint := S2 + Esize (C2_Ent);
2883 if E2 <= S1 or else E1 <= S2 then
2887 Component_Name (Component_Clause (C2_Ent));
2888 Error_Msg_Sloc := Sloc (Error_Msg_Node_2);
2890 Component_Name (Component_Clause (C1_Ent));
2892 ("component& overlaps & #",
2893 Component_Name (Component_Clause (C1_Ent)));
2897 end Check_Component_Overlap;
2899 -----------------------------------
2900 -- Check_Constant_Address_Clause --
2901 -----------------------------------
2903 procedure Check_Constant_Address_Clause
2907 procedure Check_At_Constant_Address (Nod : Node_Id);
2908 -- Checks that the given node N represents a name whose 'Address is
2909 -- constant (in the same sense as OK_Constant_Address_Clause, i.e. the
2910 -- address value is the same at the point of declaration of U_Ent and at
2911 -- the time of elaboration of the address clause.
2913 procedure Check_Expr_Constants (Nod : Node_Id);
2914 -- Checks that Nod meets the requirements for a constant address clause
2915 -- in the sense of the enclosing procedure.
2917 procedure Check_List_Constants (Lst : List_Id);
2918 -- Check that all elements of list Lst meet the requirements for a
2919 -- constant address clause in the sense of the enclosing procedure.
2921 -------------------------------
2922 -- Check_At_Constant_Address --
2923 -------------------------------
2925 procedure Check_At_Constant_Address (Nod : Node_Id) is
2927 if Is_Entity_Name (Nod) then
2928 if Present (Address_Clause (Entity ((Nod)))) then
2930 ("invalid address clause for initialized object &!",
2933 ("address for& cannot" &
2934 " depend on another address clause! (RM 13.1(22))!",
2937 elsif In_Same_Source_Unit (Entity (Nod), U_Ent)
2938 and then Sloc (U_Ent) < Sloc (Entity (Nod))
2941 ("invalid address clause for initialized object &!",
2943 Error_Msg_Name_1 := Chars (Entity (Nod));
2944 Error_Msg_Name_2 := Chars (U_Ent);
2946 ("\% must be defined before % (RM 13.1(22))!",
2950 elsif Nkind (Nod) = N_Selected_Component then
2952 T : constant Entity_Id := Etype (Prefix (Nod));
2955 if (Is_Record_Type (T)
2956 and then Has_Discriminants (T))
2959 and then Is_Record_Type (Designated_Type (T))
2960 and then Has_Discriminants (Designated_Type (T)))
2963 ("invalid address clause for initialized object &!",
2966 ("\address cannot depend on component" &
2967 " of discriminated record (RM 13.1(22))!",
2970 Check_At_Constant_Address (Prefix (Nod));
2974 elsif Nkind (Nod) = N_Indexed_Component then
2975 Check_At_Constant_Address (Prefix (Nod));
2976 Check_List_Constants (Expressions (Nod));
2979 Check_Expr_Constants (Nod);
2981 end Check_At_Constant_Address;
2983 --------------------------
2984 -- Check_Expr_Constants --
2985 --------------------------
2987 procedure Check_Expr_Constants (Nod : Node_Id) is
2988 Loc_U_Ent : constant Source_Ptr := Sloc (U_Ent);
2989 Ent : Entity_Id := Empty;
2992 if Nkind (Nod) in N_Has_Etype
2993 and then Etype (Nod) = Any_Type
2999 when N_Empty | N_Error =>
3002 when N_Identifier | N_Expanded_Name =>
3003 Ent := Entity (Nod);
3005 -- We need to look at the original node if it is different
3006 -- from the node, since we may have rewritten things and
3007 -- substituted an identifier representing the rewrite.
3009 if Original_Node (Nod) /= Nod then
3010 Check_Expr_Constants (Original_Node (Nod));
3012 -- If the node is an object declaration without initial
3013 -- value, some code has been expanded, and the expression
3014 -- is not constant, even if the constituents might be
3015 -- acceptable, as in A'Address + offset.
3017 if Ekind (Ent) = E_Variable
3019 Nkind (Declaration_Node (Ent)) = N_Object_Declaration
3021 No (Expression (Declaration_Node (Ent)))
3024 ("invalid address clause for initialized object &!",
3027 -- If entity is constant, it may be the result of expanding
3028 -- a check. We must verify that its declaration appears
3029 -- before the object in question, else we also reject the
3032 elsif Ekind (Ent) = E_Constant
3033 and then In_Same_Source_Unit (Ent, U_Ent)
3034 and then Sloc (Ent) > Loc_U_Ent
3037 ("invalid address clause for initialized object &!",
3044 -- Otherwise look at the identifier and see if it is OK
3046 if Ekind (Ent) = E_Named_Integer
3048 Ekind (Ent) = E_Named_Real
3055 Ekind (Ent) = E_Constant
3057 Ekind (Ent) = E_In_Parameter
3059 -- This is the case where we must have Ent defined before
3060 -- U_Ent. Clearly if they are in different units this
3061 -- requirement is met since the unit containing Ent is
3062 -- already processed.
3064 if not In_Same_Source_Unit (Ent, U_Ent) then
3067 -- Otherwise location of Ent must be before the location
3068 -- of U_Ent, that's what prior defined means.
3070 elsif Sloc (Ent) < Loc_U_Ent then
3075 ("invalid address clause for initialized object &!",
3077 Error_Msg_Name_1 := Chars (Ent);
3078 Error_Msg_Name_2 := Chars (U_Ent);
3080 ("\% must be defined before % (RM 13.1(22))!",
3084 elsif Nkind (Original_Node (Nod)) = N_Function_Call then
3085 Check_Expr_Constants (Original_Node (Nod));
3089 ("invalid address clause for initialized object &!",
3092 if Comes_From_Source (Ent) then
3093 Error_Msg_Name_1 := Chars (Ent);
3095 ("\reference to variable% not allowed"
3096 & " (RM 13.1(22))!", Nod);
3099 ("non-static expression not allowed"
3100 & " (RM 13.1(22))!", Nod);
3104 when N_Integer_Literal =>
3106 -- If this is a rewritten unchecked conversion, in a system
3107 -- where Address is an integer type, always use the base type
3108 -- for a literal value. This is user-friendly and prevents
3109 -- order-of-elaboration issues with instances of unchecked
3112 if Nkind (Original_Node (Nod)) = N_Function_Call then
3113 Set_Etype (Nod, Base_Type (Etype (Nod)));
3116 when N_Real_Literal |
3118 N_Character_Literal =>
3122 Check_Expr_Constants (Low_Bound (Nod));
3123 Check_Expr_Constants (High_Bound (Nod));
3125 when N_Explicit_Dereference =>
3126 Check_Expr_Constants (Prefix (Nod));
3128 when N_Indexed_Component =>
3129 Check_Expr_Constants (Prefix (Nod));
3130 Check_List_Constants (Expressions (Nod));
3133 Check_Expr_Constants (Prefix (Nod));
3134 Check_Expr_Constants (Discrete_Range (Nod));
3136 when N_Selected_Component =>
3137 Check_Expr_Constants (Prefix (Nod));
3139 when N_Attribute_Reference =>
3140 if Attribute_Name (Nod) = Name_Address
3142 Attribute_Name (Nod) = Name_Access
3144 Attribute_Name (Nod) = Name_Unchecked_Access
3146 Attribute_Name (Nod) = Name_Unrestricted_Access
3148 Check_At_Constant_Address (Prefix (Nod));
3151 Check_Expr_Constants (Prefix (Nod));
3152 Check_List_Constants (Expressions (Nod));
3156 Check_List_Constants (Component_Associations (Nod));
3157 Check_List_Constants (Expressions (Nod));
3159 when N_Component_Association =>
3160 Check_Expr_Constants (Expression (Nod));
3162 when N_Extension_Aggregate =>
3163 Check_Expr_Constants (Ancestor_Part (Nod));
3164 Check_List_Constants (Component_Associations (Nod));
3165 Check_List_Constants (Expressions (Nod));
3170 when N_Binary_Op | N_And_Then | N_Or_Else | N_Membership_Test =>
3171 Check_Expr_Constants (Left_Opnd (Nod));
3172 Check_Expr_Constants (Right_Opnd (Nod));
3175 Check_Expr_Constants (Right_Opnd (Nod));
3177 when N_Type_Conversion |
3178 N_Qualified_Expression |
3180 Check_Expr_Constants (Expression (Nod));
3182 when N_Unchecked_Type_Conversion =>
3183 Check_Expr_Constants (Expression (Nod));
3185 -- If this is a rewritten unchecked conversion, subtypes in
3186 -- this node are those created within the instance. To avoid
3187 -- order of elaboration issues, replace them with their base
3188 -- types. Note that address clauses can cause order of
3189 -- elaboration problems because they are elaborated by the
3190 -- back-end at the point of definition, and may mention
3191 -- entities declared in between (as long as everything is
3192 -- static). It is user-friendly to allow unchecked conversions
3195 if Nkind (Original_Node (Nod)) = N_Function_Call then
3196 Set_Etype (Expression (Nod),
3197 Base_Type (Etype (Expression (Nod))));
3198 Set_Etype (Nod, Base_Type (Etype (Nod)));
3201 when N_Function_Call =>
3202 if not Is_Pure (Entity (Name (Nod))) then
3204 ("invalid address clause for initialized object &!",
3208 ("\function & is not pure (RM 13.1(22))!",
3209 Nod, Entity (Name (Nod)));
3212 Check_List_Constants (Parameter_Associations (Nod));
3215 when N_Parameter_Association =>
3216 Check_Expr_Constants (Explicit_Actual_Parameter (Nod));
3220 ("invalid address clause for initialized object &!",
3223 ("\must be constant defined before& (RM 13.1(22))!",
3226 end Check_Expr_Constants;
3228 --------------------------
3229 -- Check_List_Constants --
3230 --------------------------
3232 procedure Check_List_Constants (Lst : List_Id) is
3236 if Present (Lst) then
3237 Nod1 := First (Lst);
3238 while Present (Nod1) loop
3239 Check_Expr_Constants (Nod1);
3243 end Check_List_Constants;
3245 -- Start of processing for Check_Constant_Address_Clause
3248 Check_Expr_Constants (Expr);
3249 end Check_Constant_Address_Clause;
3255 procedure Check_Size
3259 Biased : out Boolean)
3261 UT : constant Entity_Id := Underlying_Type (T);
3267 -- Dismiss cases for generic types or types with previous errors
3270 or else UT = Any_Type
3271 or else Is_Generic_Type (UT)
3272 or else Is_Generic_Type (Root_Type (UT))
3276 -- Check case of bit packed array
3278 elsif Is_Array_Type (UT)
3279 and then Known_Static_Component_Size (UT)
3280 and then Is_Bit_Packed_Array (UT)
3288 Asiz := Component_Size (UT);
3289 Indx := First_Index (UT);
3291 Ityp := Etype (Indx);
3293 -- If non-static bound, then we are not in the business of
3294 -- trying to check the length, and indeed an error will be
3295 -- issued elsewhere, since sizes of non-static array types
3296 -- cannot be set implicitly or explicitly.
3298 if not Is_Static_Subtype (Ityp) then
3302 -- Otherwise accumulate next dimension
3304 Asiz := Asiz * (Expr_Value (Type_High_Bound (Ityp)) -
3305 Expr_Value (Type_Low_Bound (Ityp)) +
3309 exit when No (Indx);
3315 Error_Msg_Uint_1 := Asiz;
3317 ("size for& too small, minimum allowed is ^", N, T);
3318 Set_Esize (T, Asiz);
3319 Set_RM_Size (T, Asiz);
3323 -- All other composite types are ignored
3325 elsif Is_Composite_Type (UT) then
3328 -- For fixed-point types, don't check minimum if type is not frozen,
3329 -- since we don't know all the characteristics of the type that can
3330 -- affect the size (e.g. a specified small) till freeze time.
3332 elsif Is_Fixed_Point_Type (UT)
3333 and then not Is_Frozen (UT)
3337 -- Cases for which a minimum check is required
3340 -- Ignore if specified size is correct for the type
3342 if Known_Esize (UT) and then Siz = Esize (UT) then
3346 -- Otherwise get minimum size
3348 M := UI_From_Int (Minimum_Size (UT));
3352 -- Size is less than minimum size, but one possibility remains
3353 -- that we can manage with the new size if we bias the type.
3355 M := UI_From_Int (Minimum_Size (UT, Biased => True));
3358 Error_Msg_Uint_1 := M;
3360 ("size for& too small, minimum allowed is ^", N, T);
3370 -------------------------
3371 -- Get_Alignment_Value --
3372 -------------------------
3374 function Get_Alignment_Value (Expr : Node_Id) return Uint is
3375 Align : constant Uint := Static_Integer (Expr);
3378 if Align = No_Uint then
3381 elsif Align <= 0 then
3382 Error_Msg_N ("alignment value must be positive", Expr);
3386 for J in Int range 0 .. 64 loop
3388 M : constant Uint := Uint_2 ** J;
3391 exit when M = Align;
3395 ("alignment value must be power of 2", Expr);
3403 end Get_Alignment_Value;
3409 procedure Initialize is
3411 Unchecked_Conversions.Init;
3414 -------------------------
3415 -- Is_Operational_Item --
3416 -------------------------
3418 function Is_Operational_Item (N : Node_Id) return Boolean is
3420 if Nkind (N) /= N_Attribute_Definition_Clause then
3424 Id : constant Attribute_Id := Get_Attribute_Id (Chars (N));
3426 return Id = Attribute_Input
3427 or else Id = Attribute_Output
3428 or else Id = Attribute_Read
3429 or else Id = Attribute_Write
3430 or else Id = Attribute_External_Tag;
3433 end Is_Operational_Item;
3439 function Minimum_Size
3441 Biased : Boolean := False) return Nat
3443 Lo : Uint := No_Uint;
3444 Hi : Uint := No_Uint;
3445 LoR : Ureal := No_Ureal;
3446 HiR : Ureal := No_Ureal;
3447 LoSet : Boolean := False;
3448 HiSet : Boolean := False;
3452 R_Typ : constant Entity_Id := Root_Type (T);
3455 -- If bad type, return 0
3457 if T = Any_Type then
3460 -- For generic types, just return zero. There cannot be any legitimate
3461 -- need to know such a size, but this routine may be called with a
3462 -- generic type as part of normal processing.
3464 elsif Is_Generic_Type (R_Typ)
3465 or else R_Typ = Any_Type
3469 -- Access types. Normally an access type cannot have a size smaller
3470 -- than the size of System.Address. The exception is on VMS, where
3471 -- we have short and long addresses, and it is possible for an access
3472 -- type to have a short address size (and thus be less than the size
3473 -- of System.Address itself). We simply skip the check for VMS, and
3474 -- leave it to the back end to do the check.
3476 elsif Is_Access_Type (T) then
3477 if OpenVMS_On_Target then
3480 return System_Address_Size;
3483 -- Floating-point types
3485 elsif Is_Floating_Point_Type (T) then
3486 return UI_To_Int (Esize (R_Typ));
3490 elsif Is_Discrete_Type (T) then
3492 -- The following loop is looking for the nearest compile time known
3493 -- bounds following the ancestor subtype chain. The idea is to find
3494 -- the most restrictive known bounds information.
3498 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3503 if Compile_Time_Known_Value (Type_Low_Bound (Ancest)) then
3504 Lo := Expr_Rep_Value (Type_Low_Bound (Ancest));
3511 if Compile_Time_Known_Value (Type_High_Bound (Ancest)) then
3512 Hi := Expr_Rep_Value (Type_High_Bound (Ancest));
3518 Ancest := Ancestor_Subtype (Ancest);
3521 Ancest := Base_Type (T);
3523 if Is_Generic_Type (Ancest) then
3529 -- Fixed-point types. We can't simply use Expr_Value to get the
3530 -- Corresponding_Integer_Value values of the bounds, since these do not
3531 -- get set till the type is frozen, and this routine can be called
3532 -- before the type is frozen. Similarly the test for bounds being static
3533 -- needs to include the case where we have unanalyzed real literals for
3536 elsif Is_Fixed_Point_Type (T) then
3538 -- The following loop is looking for the nearest compile time known
3539 -- bounds following the ancestor subtype chain. The idea is to find
3540 -- the most restrictive known bounds information.
3544 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3548 -- Note: In the following two tests for LoSet and HiSet, it may
3549 -- seem redundant to test for N_Real_Literal here since normally
3550 -- one would assume that the test for the value being known at
3551 -- compile time includes this case. However, there is a glitch.
3552 -- If the real literal comes from folding a non-static expression,
3553 -- then we don't consider any non- static expression to be known
3554 -- at compile time if we are in configurable run time mode (needed
3555 -- in some cases to give a clearer definition of what is and what
3556 -- is not accepted). So the test is indeed needed. Without it, we
3557 -- would set neither Lo_Set nor Hi_Set and get an infinite loop.
3560 if Nkind (Type_Low_Bound (Ancest)) = N_Real_Literal
3561 or else Compile_Time_Known_Value (Type_Low_Bound (Ancest))
3563 LoR := Expr_Value_R (Type_Low_Bound (Ancest));
3570 if Nkind (Type_High_Bound (Ancest)) = N_Real_Literal
3571 or else Compile_Time_Known_Value (Type_High_Bound (Ancest))
3573 HiR := Expr_Value_R (Type_High_Bound (Ancest));
3579 Ancest := Ancestor_Subtype (Ancest);
3582 Ancest := Base_Type (T);
3584 if Is_Generic_Type (Ancest) then
3590 Lo := UR_To_Uint (LoR / Small_Value (T));
3591 Hi := UR_To_Uint (HiR / Small_Value (T));
3593 -- No other types allowed
3596 raise Program_Error;
3599 -- Fall through with Hi and Lo set. Deal with biased case
3602 and then not Is_Fixed_Point_Type (T)
3603 and then not (Is_Enumeration_Type (T)
3604 and then Has_Non_Standard_Rep (T)))
3605 or else Has_Biased_Representation (T)
3611 -- Signed case. Note that we consider types like range 1 .. -1 to be
3612 -- signed for the purpose of computing the size, since the bounds have
3613 -- to be accommodated in the base type.
3615 if Lo < 0 or else Hi < 0 then
3619 -- S = size, B = 2 ** (size - 1) (can accommodate -B .. +(B - 1))
3620 -- Note that we accommodate the case where the bounds cross. This
3621 -- can happen either because of the way the bounds are declared
3622 -- or because of the algorithm in Freeze_Fixed_Point_Type.
3636 -- If both bounds are positive, make sure that both are represen-
3637 -- table in the case where the bounds are crossed. This can happen
3638 -- either because of the way the bounds are declared, or because of
3639 -- the algorithm in Freeze_Fixed_Point_Type.
3645 -- S = size, (can accommodate 0 .. (2**size - 1))
3648 while Hi >= Uint_2 ** S loop
3656 ---------------------------
3657 -- New_Stream_Subprogram --
3658 ---------------------------
3660 procedure New_Stream_Subprogram
3664 Nam : TSS_Name_Type)
3666 Loc : constant Source_Ptr := Sloc (N);
3667 Sname : constant Name_Id := Make_TSS_Name (Base_Type (Ent), Nam);
3668 Subp_Id : Entity_Id;
3669 Subp_Decl : Node_Id;
3673 Defer_Declaration : constant Boolean :=
3674 Is_Tagged_Type (Ent) or else Is_Private_Type (Ent);
3675 -- For a tagged type, there is a declaration for each stream attribute
3676 -- at the freeze point, and we must generate only a completion of this
3677 -- declaration. We do the same for private types, because the full view
3678 -- might be tagged. Otherwise we generate a declaration at the point of
3679 -- the attribute definition clause.
3681 function Build_Spec return Node_Id;
3682 -- Used for declaration and renaming declaration, so that this is
3683 -- treated as a renaming_as_body.
3689 function Build_Spec return Node_Id is
3690 Out_P : constant Boolean := (Nam = TSS_Stream_Read);
3693 T_Ref : constant Node_Id := New_Reference_To (Etyp, Loc);
3696 Subp_Id := Make_Defining_Identifier (Loc, Sname);
3698 -- S : access Root_Stream_Type'Class
3700 Formals := New_List (
3701 Make_Parameter_Specification (Loc,
3702 Defining_Identifier =>
3703 Make_Defining_Identifier (Loc, Name_S),
3705 Make_Access_Definition (Loc,
3708 Designated_Type (Etype (F)), Loc))));
3710 if Nam = TSS_Stream_Input then
3711 Spec := Make_Function_Specification (Loc,
3712 Defining_Unit_Name => Subp_Id,
3713 Parameter_Specifications => Formals,
3714 Result_Definition => T_Ref);
3719 Make_Parameter_Specification (Loc,
3720 Defining_Identifier => Make_Defining_Identifier (Loc, Name_V),
3721 Out_Present => Out_P,
3722 Parameter_Type => T_Ref));
3724 Spec := Make_Procedure_Specification (Loc,
3725 Defining_Unit_Name => Subp_Id,
3726 Parameter_Specifications => Formals);
3732 -- Start of processing for New_Stream_Subprogram
3735 F := First_Formal (Subp);
3737 if Ekind (Subp) = E_Procedure then
3738 Etyp := Etype (Next_Formal (F));
3740 Etyp := Etype (Subp);
3743 -- Prepare subprogram declaration and insert it as an action on the
3744 -- clause node. The visibility for this entity is used to test for
3745 -- visibility of the attribute definition clause (in the sense of
3746 -- 8.3(23) as amended by AI-195).
3748 if not Defer_Declaration then
3750 Make_Subprogram_Declaration (Loc,
3751 Specification => Build_Spec);
3753 -- For a tagged type, there is always a visible declaration for each
3754 -- stream TSS (it is a predefined primitive operation), and the
3755 -- completion of this declaration occurs at the freeze point, which is
3756 -- not always visible at places where the attribute definition clause is
3757 -- visible. So, we create a dummy entity here for the purpose of
3758 -- tracking the visibility of the attribute definition clause itself.
3762 Make_Defining_Identifier (Loc,
3763 Chars => New_External_Name (Sname, 'V'));
3765 Make_Object_Declaration (Loc,
3766 Defining_Identifier => Subp_Id,
3767 Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc));
3770 Insert_Action (N, Subp_Decl);
3771 Set_Entity (N, Subp_Id);
3774 Make_Subprogram_Renaming_Declaration (Loc,
3775 Specification => Build_Spec,
3776 Name => New_Reference_To (Subp, Loc));
3778 if Defer_Declaration then
3779 Set_TSS (Base_Type (Ent), Subp_Id);
3781 Insert_Action (N, Subp_Decl);
3782 Copy_TSS (Subp_Id, Base_Type (Ent));
3784 end New_Stream_Subprogram;
3786 ------------------------
3787 -- Rep_Item_Too_Early --
3788 ------------------------
3790 function Rep_Item_Too_Early (T : Entity_Id; N : Node_Id) return Boolean is
3792 -- Cannot apply non-operational rep items to generic types
3794 if Is_Operational_Item (N) then
3798 and then Is_Generic_Type (Root_Type (T))
3801 ("representation item not allowed for generic type", N);
3805 -- Otherwise check for incomplete type
3807 if Is_Incomplete_Or_Private_Type (T)
3808 and then No (Underlying_Type (T))
3811 ("representation item must be after full type declaration", N);
3814 -- If the type has incomplete components, a representation clause is
3815 -- illegal but stream attributes and Convention pragmas are correct.
3817 elsif Has_Private_Component (T) then
3818 if Nkind (N) = N_Pragma then
3822 ("representation item must appear after type is fully defined",
3829 end Rep_Item_Too_Early;
3831 -----------------------
3832 -- Rep_Item_Too_Late --
3833 -----------------------
3835 function Rep_Item_Too_Late
3838 FOnly : Boolean := False) return Boolean
3841 Parent_Type : Entity_Id;
3844 -- Output the too late message. Note that this is not considered a
3845 -- serious error, since the effect is simply that we ignore the
3846 -- representation clause in this case.
3852 procedure Too_Late is
3854 Error_Msg_N ("|representation item appears too late!", N);
3857 -- Start of processing for Rep_Item_Too_Late
3860 -- First make sure entity is not frozen (RM 13.1(9)). Exclude imported
3861 -- types, which may be frozen if they appear in a representation clause
3862 -- for a local type.
3865 and then not From_With_Type (T)
3868 S := First_Subtype (T);
3870 if Present (Freeze_Node (S)) then
3872 ("?no more representation items for }", Freeze_Node (S), S);
3877 -- Check for case of non-tagged derived type whose parent either has
3878 -- primitive operations, or is a by reference type (RM 13.1(10)).
3882 and then Is_Derived_Type (T)
3883 and then not Is_Tagged_Type (T)
3885 Parent_Type := Etype (Base_Type (T));
3887 if Has_Primitive_Operations (Parent_Type) then
3890 ("primitive operations already defined for&!", N, Parent_Type);
3893 elsif Is_By_Reference_Type (Parent_Type) then
3896 ("parent type & is a by reference type!", N, Parent_Type);
3901 -- No error, link item into head of chain of rep items for the entity,
3902 -- but avoid chaining if we have an overloadable entity, and the pragma
3903 -- is one that can apply to multiple overloaded entities.
3905 if Is_Overloadable (T)
3906 and then Nkind (N) = N_Pragma
3909 Pname : constant Name_Id := Pragma_Name (N);
3911 if Pname = Name_Convention or else
3912 Pname = Name_Import or else
3913 Pname = Name_Export or else
3914 Pname = Name_External or else
3915 Pname = Name_Interface
3922 Record_Rep_Item (T, N);
3924 end Rep_Item_Too_Late;
3926 -------------------------
3927 -- Same_Representation --
3928 -------------------------
3930 function Same_Representation (Typ1, Typ2 : Entity_Id) return Boolean is
3931 T1 : constant Entity_Id := Underlying_Type (Typ1);
3932 T2 : constant Entity_Id := Underlying_Type (Typ2);
3935 -- A quick check, if base types are the same, then we definitely have
3936 -- the same representation, because the subtype specific representation
3937 -- attributes (Size and Alignment) do not affect representation from
3938 -- the point of view of this test.
3940 if Base_Type (T1) = Base_Type (T2) then
3943 elsif Is_Private_Type (Base_Type (T2))
3944 and then Base_Type (T1) = Full_View (Base_Type (T2))
3949 -- Tagged types never have differing representations
3951 if Is_Tagged_Type (T1) then
3955 -- Representations are definitely different if conventions differ
3957 if Convention (T1) /= Convention (T2) then
3961 -- Representations are different if component alignments differ
3963 if (Is_Record_Type (T1) or else Is_Array_Type (T1))
3965 (Is_Record_Type (T2) or else Is_Array_Type (T2))
3966 and then Component_Alignment (T1) /= Component_Alignment (T2)
3971 -- For arrays, the only real issue is component size. If we know the
3972 -- component size for both arrays, and it is the same, then that's
3973 -- good enough to know we don't have a change of representation.
3975 if Is_Array_Type (T1) then
3976 if Known_Component_Size (T1)
3977 and then Known_Component_Size (T2)
3978 and then Component_Size (T1) = Component_Size (T2)
3984 -- Types definitely have same representation if neither has non-standard
3985 -- representation since default representations are always consistent.
3986 -- If only one has non-standard representation, and the other does not,
3987 -- then we consider that they do not have the same representation. They
3988 -- might, but there is no way of telling early enough.
3990 if Has_Non_Standard_Rep (T1) then
3991 if not Has_Non_Standard_Rep (T2) then
3995 return not Has_Non_Standard_Rep (T2);
3998 -- Here the two types both have non-standard representation, and we need
3999 -- to determine if they have the same non-standard representation.
4001 -- For arrays, we simply need to test if the component sizes are the
4002 -- same. Pragma Pack is reflected in modified component sizes, so this
4003 -- check also deals with pragma Pack.
4005 if Is_Array_Type (T1) then
4006 return Component_Size (T1) = Component_Size (T2);
4008 -- Tagged types always have the same representation, because it is not
4009 -- possible to specify different representations for common fields.
4011 elsif Is_Tagged_Type (T1) then
4014 -- Case of record types
4016 elsif Is_Record_Type (T1) then
4018 -- Packed status must conform
4020 if Is_Packed (T1) /= Is_Packed (T2) then
4023 -- Otherwise we must check components. Typ2 maybe a constrained
4024 -- subtype with fewer components, so we compare the components
4025 -- of the base types.
4028 Record_Case : declare
4029 CD1, CD2 : Entity_Id;
4031 function Same_Rep return Boolean;
4032 -- CD1 and CD2 are either components or discriminants. This
4033 -- function tests whether the two have the same representation
4039 function Same_Rep return Boolean is
4041 if No (Component_Clause (CD1)) then
4042 return No (Component_Clause (CD2));
4046 Present (Component_Clause (CD2))
4048 Component_Bit_Offset (CD1) = Component_Bit_Offset (CD2)
4050 Esize (CD1) = Esize (CD2);
4054 -- Start of processing for Record_Case
4057 if Has_Discriminants (T1) then
4058 CD1 := First_Discriminant (T1);
4059 CD2 := First_Discriminant (T2);
4061 -- The number of discriminants may be different if the
4062 -- derived type has fewer (constrained by values). The
4063 -- invisible discriminants retain the representation of
4064 -- the original, so the discrepancy does not per se
4065 -- indicate a different representation.
4068 and then Present (CD2)
4070 if not Same_Rep then
4073 Next_Discriminant (CD1);
4074 Next_Discriminant (CD2);
4079 CD1 := First_Component (Underlying_Type (Base_Type (T1)));
4080 CD2 := First_Component (Underlying_Type (Base_Type (T2)));
4082 while Present (CD1) loop
4083 if not Same_Rep then
4086 Next_Component (CD1);
4087 Next_Component (CD2);
4095 -- For enumeration types, we must check each literal to see if the
4096 -- representation is the same. Note that we do not permit enumeration
4097 -- representation clauses for Character and Wide_Character, so these
4098 -- cases were already dealt with.
4100 elsif Is_Enumeration_Type (T1) then
4102 Enumeration_Case : declare
4106 L1 := First_Literal (T1);
4107 L2 := First_Literal (T2);
4109 while Present (L1) loop
4110 if Enumeration_Rep (L1) /= Enumeration_Rep (L2) then
4120 end Enumeration_Case;
4122 -- Any other types have the same representation for these purposes
4127 end Same_Representation;
4129 --------------------
4130 -- Set_Enum_Esize --
4131 --------------------
4133 procedure Set_Enum_Esize (T : Entity_Id) is
4141 -- Find the minimum standard size (8,16,32,64) that fits
4143 Lo := Enumeration_Rep (Entity (Type_Low_Bound (T)));
4144 Hi := Enumeration_Rep (Entity (Type_High_Bound (T)));
4147 if Lo >= -Uint_2**07 and then Hi < Uint_2**07 then
4148 Sz := Standard_Character_Size; -- May be > 8 on some targets
4150 elsif Lo >= -Uint_2**15 and then Hi < Uint_2**15 then
4153 elsif Lo >= -Uint_2**31 and then Hi < Uint_2**31 then
4156 else pragma Assert (Lo >= -Uint_2**63 and then Hi < Uint_2**63);
4161 if Hi < Uint_2**08 then
4162 Sz := Standard_Character_Size; -- May be > 8 on some targets
4164 elsif Hi < Uint_2**16 then
4167 elsif Hi < Uint_2**32 then
4170 else pragma Assert (Hi < Uint_2**63);
4175 -- That minimum is the proper size unless we have a foreign convention
4176 -- and the size required is 32 or less, in which case we bump the size
4177 -- up to 32. This is required for C and C++ and seems reasonable for
4178 -- all other foreign conventions.
4180 if Has_Foreign_Convention (T)
4181 and then Esize (T) < Standard_Integer_Size
4183 Init_Esize (T, Standard_Integer_Size);
4189 ------------------------------
4190 -- Validate_Address_Clauses --
4191 ------------------------------
4193 procedure Validate_Address_Clauses is
4195 for J in Address_Clause_Checks.First .. Address_Clause_Checks.Last loop
4197 ACCR : Address_Clause_Check_Record
4198 renames Address_Clause_Checks.Table (J);
4207 -- Skip processing of this entry if warning already posted
4209 if not Address_Warning_Posted (ACCR.N) then
4211 -- Get alignments. Really we should always have the alignment
4212 -- of the objects properly back annotated, but right now the
4213 -- back end fails to back annotate for address clauses???
4215 if Known_Alignment (ACCR.X) then
4216 X_Alignment := Alignment (ACCR.X);
4218 X_Alignment := Alignment (Etype (ACCR.X));
4221 if Known_Alignment (ACCR.Y) then
4222 Y_Alignment := Alignment (ACCR.Y);
4224 Y_Alignment := Alignment (Etype (ACCR.Y));
4227 -- Similarly obtain sizes
4229 if Known_Esize (ACCR.X) then
4230 X_Size := Esize (ACCR.X);
4232 X_Size := Esize (Etype (ACCR.X));
4235 if Known_Esize (ACCR.Y) then
4236 Y_Size := Esize (ACCR.Y);
4238 Y_Size := Esize (Etype (ACCR.Y));
4241 -- Check for large object overlaying smaller one
4244 and then X_Size > Uint_0
4245 and then X_Size > Y_Size
4248 ("?size for overlaid object is too small", ACCR.N);
4249 Error_Msg_Uint_1 := X_Size;
4251 ("\?size of & is ^", ACCR.N, ACCR.X);
4252 Error_Msg_Uint_1 := Y_Size;
4254 ("\?size of & is ^", ACCR.N, ACCR.Y);
4256 -- Check for inadequate alignment. Again the defensive check
4257 -- on Y_Alignment should not be needed, but because of the
4258 -- failure in back end annotation, we can have an alignment
4261 -- Note: we do not check alignments if we gave a size
4262 -- warning, since it would likely be redundant.
4264 elsif Y_Alignment /= Uint_0
4265 and then Y_Alignment < X_Alignment
4268 ("?specified address for& may be inconsistent "
4272 ("\?program execution may be erroneous (RM 13.3(27))",
4274 Error_Msg_Uint_1 := X_Alignment;
4276 ("\?alignment of & is ^",
4278 Error_Msg_Uint_1 := Y_Alignment;
4280 ("\?alignment of & is ^",
4286 end Validate_Address_Clauses;
4288 -----------------------------------
4289 -- Validate_Unchecked_Conversion --
4290 -----------------------------------
4292 procedure Validate_Unchecked_Conversion
4294 Act_Unit : Entity_Id)
4301 -- Obtain source and target types. Note that we call Ancestor_Subtype
4302 -- here because the processing for generic instantiation always makes
4303 -- subtypes, and we want the original frozen actual types.
4305 -- If we are dealing with private types, then do the check on their
4306 -- fully declared counterparts if the full declarations have been
4307 -- encountered (they don't have to be visible, but they must exist!)
4309 Source := Ancestor_Subtype (Etype (First_Formal (Act_Unit)));
4311 if Is_Private_Type (Source)
4312 and then Present (Underlying_Type (Source))
4314 Source := Underlying_Type (Source);
4317 Target := Ancestor_Subtype (Etype (Act_Unit));
4319 -- If either type is generic, the instantiation happens within a generic
4320 -- unit, and there is nothing to check. The proper check
4321 -- will happen when the enclosing generic is instantiated.
4323 if Is_Generic_Type (Source) or else Is_Generic_Type (Target) then
4327 if Is_Private_Type (Target)
4328 and then Present (Underlying_Type (Target))
4330 Target := Underlying_Type (Target);
4333 -- Source may be unconstrained array, but not target
4335 if Is_Array_Type (Target)
4336 and then not Is_Constrained (Target)
4339 ("unchecked conversion to unconstrained array not allowed", N);
4343 -- Warn if conversion between two different convention pointers
4345 if Is_Access_Type (Target)
4346 and then Is_Access_Type (Source)
4347 and then Convention (Target) /= Convention (Source)
4348 and then Warn_On_Unchecked_Conversion
4350 -- Give warnings for subprogram pointers only on most targets. The
4351 -- exception is VMS, where data pointers can have different lengths
4352 -- depending on the pointer convention.
4354 if Is_Access_Subprogram_Type (Target)
4355 or else Is_Access_Subprogram_Type (Source)
4356 or else OpenVMS_On_Target
4359 ("?conversion between pointers with different conventions!", N);
4363 -- Warn if one of the operands is Ada.Calendar.Time. Do not emit a
4364 -- warning when compiling GNAT-related sources.
4366 if Warn_On_Unchecked_Conversion
4367 and then not In_Predefined_Unit (N)
4368 and then RTU_Loaded (Ada_Calendar)
4370 (Chars (Source) = Name_Time
4372 Chars (Target) = Name_Time)
4374 -- If Ada.Calendar is loaded and the name of one of the operands is
4375 -- Time, there is a good chance that this is Ada.Calendar.Time.
4378 Calendar_Time : constant Entity_Id :=
4379 Full_View (RTE (RO_CA_Time));
4381 pragma Assert (Present (Calendar_Time));
4383 if Source = Calendar_Time
4384 or else Target = Calendar_Time
4387 ("?representation of 'Time values may change between " &
4388 "'G'N'A'T versions", N);
4393 -- Make entry in unchecked conversion table for later processing by
4394 -- Validate_Unchecked_Conversions, which will check sizes and alignments
4395 -- (using values set by the back-end where possible). This is only done
4396 -- if the appropriate warning is active.
4398 if Warn_On_Unchecked_Conversion then
4399 Unchecked_Conversions.Append
4400 (New_Val => UC_Entry'
4405 -- If both sizes are known statically now, then back end annotation
4406 -- is not required to do a proper check but if either size is not
4407 -- known statically, then we need the annotation.
4409 if Known_Static_RM_Size (Source)
4410 and then Known_Static_RM_Size (Target)
4414 Back_Annotate_Rep_Info := True;
4418 -- If unchecked conversion to access type, and access type is declared
4419 -- in the same unit as the unchecked conversion, then set the
4420 -- No_Strict_Aliasing flag (no strict aliasing is implicit in this
4423 if Is_Access_Type (Target) and then
4424 In_Same_Source_Unit (Target, N)
4426 Set_No_Strict_Aliasing (Implementation_Base_Type (Target));
4429 -- Generate N_Validate_Unchecked_Conversion node for back end in
4430 -- case the back end needs to perform special validation checks.
4432 -- Shouldn't this be in Exp_Ch13, since the check only gets done
4433 -- if we have full expansion and the back end is called ???
4436 Make_Validate_Unchecked_Conversion (Sloc (N));
4437 Set_Source_Type (Vnode, Source);
4438 Set_Target_Type (Vnode, Target);
4440 -- If the unchecked conversion node is in a list, just insert before it.
4441 -- If not we have some strange case, not worth bothering about.
4443 if Is_List_Member (N) then
4444 Insert_After (N, Vnode);
4446 end Validate_Unchecked_Conversion;
4448 ------------------------------------
4449 -- Validate_Unchecked_Conversions --
4450 ------------------------------------
4452 procedure Validate_Unchecked_Conversions is
4454 for N in Unchecked_Conversions.First .. Unchecked_Conversions.Last loop
4456 T : UC_Entry renames Unchecked_Conversions.Table (N);
4458 Enode : constant Node_Id := T.Enode;
4459 Source : constant Entity_Id := T.Source;
4460 Target : constant Entity_Id := T.Target;
4466 -- This validation check, which warns if we have unequal sizes for
4467 -- unchecked conversion, and thus potentially implementation
4468 -- dependent semantics, is one of the few occasions on which we
4469 -- use the official RM size instead of Esize. See description in
4470 -- Einfo "Handling of Type'Size Values" for details.
4472 if Serious_Errors_Detected = 0
4473 and then Known_Static_RM_Size (Source)
4474 and then Known_Static_RM_Size (Target)
4476 Source_Siz := RM_Size (Source);
4477 Target_Siz := RM_Size (Target);
4479 if Source_Siz /= Target_Siz then
4481 ("?types for unchecked conversion have different sizes!",
4484 if All_Errors_Mode then
4485 Error_Msg_Name_1 := Chars (Source);
4486 Error_Msg_Uint_1 := Source_Siz;
4487 Error_Msg_Name_2 := Chars (Target);
4488 Error_Msg_Uint_2 := Target_Siz;
4490 ("\size of % is ^, size of % is ^?", Enode);
4492 Error_Msg_Uint_1 := UI_Abs (Source_Siz - Target_Siz);
4494 if Is_Discrete_Type (Source)
4495 and then Is_Discrete_Type (Target)
4497 if Source_Siz > Target_Siz then
4499 ("\?^ high order bits of source will be ignored!",
4502 elsif Is_Unsigned_Type (Source) then
4504 ("\?source will be extended with ^ high order " &
4505 "zero bits?!", Enode);
4509 ("\?source will be extended with ^ high order " &
4514 elsif Source_Siz < Target_Siz then
4515 if Is_Discrete_Type (Target) then
4516 if Bytes_Big_Endian then
4518 ("\?target value will include ^ undefined " &
4523 ("\?target value will include ^ undefined " &
4530 ("\?^ trailing bits of target value will be " &
4531 "undefined!", Enode);
4534 else pragma Assert (Source_Siz > Target_Siz);
4536 ("\?^ trailing bits of source will be ignored!",
4543 -- If both types are access types, we need to check the alignment.
4544 -- If the alignment of both is specified, we can do it here.
4546 if Serious_Errors_Detected = 0
4547 and then Ekind (Source) in Access_Kind
4548 and then Ekind (Target) in Access_Kind
4549 and then Target_Strict_Alignment
4550 and then Present (Designated_Type (Source))
4551 and then Present (Designated_Type (Target))
4554 D_Source : constant Entity_Id := Designated_Type (Source);
4555 D_Target : constant Entity_Id := Designated_Type (Target);
4558 if Known_Alignment (D_Source)
4559 and then Known_Alignment (D_Target)
4562 Source_Align : constant Uint := Alignment (D_Source);
4563 Target_Align : constant Uint := Alignment (D_Target);
4566 if Source_Align < Target_Align
4567 and then not Is_Tagged_Type (D_Source)
4569 Error_Msg_Uint_1 := Target_Align;
4570 Error_Msg_Uint_2 := Source_Align;
4571 Error_Msg_Node_2 := D_Source;
4573 ("?alignment of & (^) is stricter than " &
4574 "alignment of & (^)!", Enode, D_Target);
4576 if All_Errors_Mode then
4578 ("\?resulting access value may have invalid " &
4579 "alignment!", Enode);
4588 end Validate_Unchecked_Conversions;