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_Ch8; use Sem_Ch8;
43 with Sem_Eval; use Sem_Eval;
44 with Sem_Res; use Sem_Res;
45 with Sem_Type; use Sem_Type;
46 with Sem_Util; use Sem_Util;
47 with Sem_Warn; use Sem_Warn;
48 with Snames; use Snames;
49 with Stand; use Stand;
50 with Sinfo; use Sinfo;
52 with Targparm; use Targparm;
53 with Ttypes; use Ttypes;
54 with Tbuild; use Tbuild;
55 with Urealp; use Urealp;
57 with GNAT.Heap_Sort_G;
59 package body Sem_Ch13 is
61 SSU : constant Pos := System_Storage_Unit;
62 -- Convenient short hand for commonly used constant
64 -----------------------
65 -- Local Subprograms --
66 -----------------------
68 procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id);
69 -- This routine is called after setting the Esize of type entity Typ.
70 -- The purpose is to deal with the situation where an alignment has been
71 -- inherited from a derived type that is no longer appropriate for the
72 -- new Esize value. In this case, we reset the Alignment to unknown.
74 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id);
75 -- Given two entities for record components or discriminants, checks
76 -- if they have overlapping component clauses and issues errors if so.
78 function Get_Alignment_Value (Expr : Node_Id) return Uint;
79 -- Given the expression for an alignment value, returns the corresponding
80 -- Uint value. If the value is inappropriate, then error messages are
81 -- posted as required, and a value of No_Uint is returned.
83 function Is_Operational_Item (N : Node_Id) return Boolean;
84 -- A specification for a stream attribute is allowed before the full
85 -- type is declared, as explained in AI-00137 and the corrigendum.
86 -- Attributes that do not specify a representation characteristic are
87 -- operational attributes.
89 function Address_Aliased_Entity (N : Node_Id) return Entity_Id;
90 -- If expression N is of the form E'Address, return E
92 procedure New_Stream_Subprogram
97 -- Create a subprogram renaming of a given stream attribute to the
98 -- designated subprogram and then in the tagged case, provide this as a
99 -- primitive operation, or in the non-tagged case make an appropriate TSS
100 -- entry. This is more properly an expansion activity than just semantics,
101 -- but the presence of user-defined stream functions for limited types is a
102 -- legality check, which is why this takes place here rather than in
103 -- exp_ch13, where it was previously. Nam indicates the name of the TSS
104 -- function to be generated.
106 -- To avoid elaboration anomalies with freeze nodes, for untagged types
107 -- we generate both a subprogram declaration and a subprogram renaming
108 -- declaration, so that the attribute specification is handled as a
109 -- renaming_as_body. For tagged types, the specification is one of the
112 ----------------------------------------------
113 -- Table for Validate_Unchecked_Conversions --
114 ----------------------------------------------
116 -- The following table collects unchecked conversions for validation.
117 -- Entries are made by Validate_Unchecked_Conversion and then the
118 -- call to Validate_Unchecked_Conversions does the actual error
119 -- checking and posting of warnings. The reason for this delayed
120 -- processing is to take advantage of back-annotations of size and
121 -- alignment values performed by the back end.
123 type UC_Entry is record
124 Enode : Node_Id; -- node used for posting warnings
125 Source : Entity_Id; -- source type for unchecked conversion
126 Target : Entity_Id; -- target type for unchecked conversion
129 package Unchecked_Conversions is new Table.Table (
130 Table_Component_Type => UC_Entry,
131 Table_Index_Type => Int,
132 Table_Low_Bound => 1,
134 Table_Increment => 200,
135 Table_Name => "Unchecked_Conversions");
137 ----------------------------------------
138 -- Table for Validate_Address_Clauses --
139 ----------------------------------------
141 -- If an address clause has the form
143 -- for X'Address use Expr
145 -- where Expr is of the form Y'Address or recursively is a reference
146 -- to a constant of either of these forms, and X and Y are entities of
147 -- objects, then if Y has a smaller alignment than X, that merits a
148 -- warning about possible bad alignment. The following table collects
149 -- address clauses of this kind. We put these in a table so that they
150 -- can be checked after the back end has completed annotation of the
151 -- alignments of objects, since we can catch more cases that way.
153 type Address_Clause_Check_Record is record
155 -- The address clause
158 -- The entity of the object overlaying Y
161 -- The entity of the object being overlaid
164 package Address_Clause_Checks is new Table.Table (
165 Table_Component_Type => Address_Clause_Check_Record,
166 Table_Index_Type => Int,
167 Table_Low_Bound => 1,
169 Table_Increment => 200,
170 Table_Name => "Address_Clause_Checks");
172 ----------------------------
173 -- Address_Aliased_Entity --
174 ----------------------------
176 function Address_Aliased_Entity (N : Node_Id) return Entity_Id is
178 if Nkind (N) = N_Attribute_Reference
179 and then Attribute_Name (N) = Name_Address
186 while Nkind_In (P, N_Selected_Component, N_Indexed_Component) loop
190 if Is_Entity_Name (P) then
197 end Address_Aliased_Entity;
199 -----------------------------------------
200 -- Adjust_Record_For_Reverse_Bit_Order --
201 -----------------------------------------
203 procedure Adjust_Record_For_Reverse_Bit_Order (R : Entity_Id) is
204 Max_Machine_Scalar_Size : constant Uint :=
206 (Standard_Long_Long_Integer_Size);
207 -- We use this as the maximum machine scalar size in the sense of AI-133
211 SSU : constant Uint := UI_From_Int (System_Storage_Unit);
214 -- This first loop through components does two things. First it deals
215 -- with the case of components with component clauses whose length is
216 -- greater than the maximum machine scalar size (either accepting them
217 -- or rejecting as needed). Second, it counts the number of components
218 -- with component clauses whose length does not exceed this maximum for
222 Comp := First_Component_Or_Discriminant (R);
223 while Present (Comp) loop
225 CC : constant Node_Id := Component_Clause (Comp);
226 Fbit : constant Uint := Static_Integer (First_Bit (CC));
231 -- Case of component with size > max machine scalar
233 if Esize (Comp) > Max_Machine_Scalar_Size then
235 -- Must begin on byte boundary
237 if Fbit mod SSU /= 0 then
239 ("illegal first bit value for reverse bit order",
241 Error_Msg_Uint_1 := SSU;
242 Error_Msg_Uint_2 := Max_Machine_Scalar_Size;
245 ("\must be a multiple of ^ if size greater than ^",
248 -- Must end on byte boundary
250 elsif Esize (Comp) mod SSU /= 0 then
252 ("illegal last bit value for reverse bit order",
254 Error_Msg_Uint_1 := SSU;
255 Error_Msg_Uint_2 := Max_Machine_Scalar_Size;
258 ("\must be a multiple of ^ if size greater than ^",
261 -- OK, give warning if enabled
263 elsif Warn_On_Reverse_Bit_Order then
265 ("multi-byte field specified with non-standard"
266 & " Bit_Order?", CC);
268 if Bytes_Big_Endian then
270 ("\bytes are not reversed "
271 & "(component is big-endian)?", CC);
274 ("\bytes are not reversed "
275 & "(component is little-endian)?", CC);
279 -- Case where size is not greater than max machine scalar.
280 -- For now, we just count these.
283 Num_CC := Num_CC + 1;
288 Next_Component_Or_Discriminant (Comp);
291 -- We need to sort the component clauses on the basis of the Position
292 -- values in the clause, so we can group clauses with the same Position.
293 -- together to determine the relevant machine scalar size.
296 Comps : array (0 .. Num_CC) of Entity_Id;
297 -- Array to collect component and discriminant entities. The data
298 -- starts at index 1, the 0'th entry is for the sort routine.
300 function CP_Lt (Op1, Op2 : Natural) return Boolean;
301 -- Compare routine for Sort
303 procedure CP_Move (From : Natural; To : Natural);
304 -- Move routine for Sort
306 package Sorting is new GNAT.Heap_Sort_G (CP_Move, CP_Lt);
310 -- Start and stop positions in component list of set of components
311 -- with the same starting position (that constitute components in
312 -- a single machine scalar).
315 -- Maximum last bit value of any component in this set
318 -- Corresponding machine scalar size
324 function CP_Lt (Op1, Op2 : Natural) return Boolean is
326 return Position (Component_Clause (Comps (Op1))) <
327 Position (Component_Clause (Comps (Op2)));
334 procedure CP_Move (From : Natural; To : Natural) is
336 Comps (To) := Comps (From);
340 -- Collect the component clauses
343 Comp := First_Component_Or_Discriminant (R);
344 while Present (Comp) loop
345 if Present (Component_Clause (Comp))
346 and then Esize (Comp) <= Max_Machine_Scalar_Size
348 Num_CC := Num_CC + 1;
349 Comps (Num_CC) := Comp;
352 Next_Component_Or_Discriminant (Comp);
355 -- Sort by ascending position number
357 Sorting.Sort (Num_CC);
359 -- We now have all the components whose size does not exceed the max
360 -- machine scalar value, sorted by starting position. In this loop
361 -- we gather groups of clauses starting at the same position, to
362 -- process them in accordance with Ada 2005 AI-133.
365 while Stop < Num_CC loop
369 Static_Integer (Last_Bit (Component_Clause (Comps (Start))));
370 while Stop < Num_CC loop
372 (Position (Component_Clause (Comps (Stop + 1)))) =
374 (Position (Component_Clause (Comps (Stop))))
381 (Last_Bit (Component_Clause (Comps (Stop)))));
387 -- Now we have a group of component clauses from Start to Stop
388 -- whose positions are identical, and MaxL is the maximum last bit
389 -- value of any of these components.
391 -- We need to determine the corresponding machine scalar size.
392 -- This loop assumes that machine scalar sizes are even, and that
393 -- each possible machine scalar has twice as many bits as the
396 MSS := Max_Machine_Scalar_Size;
398 and then (MSS / 2) >= SSU
399 and then (MSS / 2) > MaxL
404 -- Here is where we fix up the Component_Bit_Offset value to
405 -- account for the reverse bit order. Some examples of what needs
406 -- to be done for the case of a machine scalar size of 8 are:
408 -- First_Bit .. Last_Bit Component_Bit_Offset
420 -- The general rule is that the first bit is is obtained by
421 -- subtracting the old ending bit from machine scalar size - 1.
423 for C in Start .. Stop loop
425 Comp : constant Entity_Id := Comps (C);
426 CC : constant Node_Id := Component_Clause (Comp);
427 LB : constant Uint := Static_Integer (Last_Bit (CC));
428 NFB : constant Uint := MSS - Uint_1 - LB;
429 NLB : constant Uint := NFB + Esize (Comp) - 1;
430 Pos : constant Uint := Static_Integer (Position (CC));
433 if Warn_On_Reverse_Bit_Order then
434 Error_Msg_Uint_1 := MSS;
436 ("?reverse bit order in machine " &
437 "scalar of length^", First_Bit (CC));
438 Error_Msg_Uint_1 := NFB;
439 Error_Msg_Uint_2 := NLB;
441 if Bytes_Big_Endian then
443 ("?\big-endian range for component & is ^ .. ^",
444 First_Bit (CC), Comp);
447 ("?\little-endian range for component & is ^ .. ^",
448 First_Bit (CC), Comp);
452 Set_Component_Bit_Offset (Comp, Pos * SSU + NFB);
453 Set_Normalized_First_Bit (Comp, NFB mod SSU);
458 end Adjust_Record_For_Reverse_Bit_Order;
460 --------------------------------------
461 -- Alignment_Check_For_Esize_Change --
462 --------------------------------------
464 procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id) is
466 -- If the alignment is known, and not set by a rep clause, and is
467 -- inconsistent with the size being set, then reset it to unknown,
468 -- we assume in this case that the size overrides the inherited
469 -- alignment, and that the alignment must be recomputed.
471 if Known_Alignment (Typ)
472 and then not Has_Alignment_Clause (Typ)
473 and then Esize (Typ) mod (Alignment (Typ) * SSU) /= 0
475 Init_Alignment (Typ);
477 end Alignment_Check_For_Esize_Change;
479 -----------------------
480 -- Analyze_At_Clause --
481 -----------------------
483 -- An at clause is replaced by the corresponding Address attribute
484 -- definition clause that is the preferred approach in Ada 95.
486 procedure Analyze_At_Clause (N : Node_Id) is
487 CS : constant Boolean := Comes_From_Source (N);
490 -- This is an obsolescent feature
492 Check_Restriction (No_Obsolescent_Features, N);
494 if Warn_On_Obsolescent_Feature then
496 ("at clause is an obsolescent feature (RM J.7(2))?", N);
498 ("\use address attribute definition clause instead?", N);
501 -- Rewrite as address clause
504 Make_Attribute_Definition_Clause (Sloc (N),
505 Name => Identifier (N),
506 Chars => Name_Address,
507 Expression => Expression (N)));
509 -- We preserve Comes_From_Source, since logically the clause still
510 -- comes from the source program even though it is changed in form.
512 Set_Comes_From_Source (N, CS);
514 -- Analyze rewritten clause
516 Analyze_Attribute_Definition_Clause (N);
517 end Analyze_At_Clause;
519 -----------------------------------------
520 -- Analyze_Attribute_Definition_Clause --
521 -----------------------------------------
523 procedure Analyze_Attribute_Definition_Clause (N : Node_Id) is
524 Loc : constant Source_Ptr := Sloc (N);
525 Nam : constant Node_Id := Name (N);
526 Attr : constant Name_Id := Chars (N);
527 Expr : constant Node_Id := Expression (N);
528 Id : constant Attribute_Id := Get_Attribute_Id (Attr);
532 FOnly : Boolean := False;
533 -- Reset to True for subtype specific attribute (Alignment, Size)
534 -- and for stream attributes, i.e. those cases where in the call
535 -- to Rep_Item_Too_Late, FOnly is set True so that only the freezing
536 -- rules are checked. Note that the case of stream attributes is not
537 -- clear from the RM, but see AI95-00137. Also, the RM seems to
538 -- disallow Storage_Size for derived task types, but that is also
539 -- clearly unintentional.
541 procedure Analyze_Stream_TSS_Definition (TSS_Nam : TSS_Name_Type);
542 -- Common processing for 'Read, 'Write, 'Input and 'Output attribute
543 -- definition clauses.
545 -----------------------------------
546 -- Analyze_Stream_TSS_Definition --
547 -----------------------------------
549 procedure Analyze_Stream_TSS_Definition (TSS_Nam : TSS_Name_Type) is
550 Subp : Entity_Id := Empty;
555 Is_Read : constant Boolean := (TSS_Nam = TSS_Stream_Read);
557 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
558 -- Return true if the entity is a subprogram with an appropriate
559 -- profile for the attribute being defined.
561 ----------------------
562 -- Has_Good_Profile --
563 ----------------------
565 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
567 Is_Function : constant Boolean := (TSS_Nam = TSS_Stream_Input);
568 Expected_Ekind : constant array (Boolean) of Entity_Kind :=
569 (False => E_Procedure, True => E_Function);
573 if Ekind (Subp) /= Expected_Ekind (Is_Function) then
577 F := First_Formal (Subp);
580 or else Ekind (Etype (F)) /= E_Anonymous_Access_Type
581 or else Designated_Type (Etype (F)) /=
582 Class_Wide_Type (RTE (RE_Root_Stream_Type))
587 if not Is_Function then
591 Expected_Mode : constant array (Boolean) of Entity_Kind :=
592 (False => E_In_Parameter,
593 True => E_Out_Parameter);
595 if Parameter_Mode (F) /= Expected_Mode (Is_Read) then
606 return Base_Type (Typ) = Base_Type (Ent)
607 and then No (Next_Formal (F));
608 end Has_Good_Profile;
610 -- Start of processing for Analyze_Stream_TSS_Definition
615 if not Is_Type (U_Ent) then
616 Error_Msg_N ("local name must be a subtype", Nam);
620 Pnam := TSS (Base_Type (U_Ent), TSS_Nam);
622 -- If Pnam is present, it can be either inherited from an ancestor
623 -- type (in which case it is legal to redefine it for this type), or
624 -- be a previous definition of the attribute for the same type (in
625 -- which case it is illegal).
627 -- In the first case, it will have been analyzed already, and we
628 -- can check that its profile does not match the expected profile
629 -- for a stream attribute of U_Ent. In the second case, either Pnam
630 -- has been analyzed (and has the expected profile), or it has not
631 -- been analyzed yet (case of a type that has not been frozen yet
632 -- and for which the stream attribute has been set using Set_TSS).
635 and then (No (First_Entity (Pnam)) or else Has_Good_Profile (Pnam))
637 Error_Msg_Sloc := Sloc (Pnam);
638 Error_Msg_Name_1 := Attr;
639 Error_Msg_N ("% attribute already defined #", Nam);
645 if Is_Entity_Name (Expr) then
646 if not Is_Overloaded (Expr) then
647 if Has_Good_Profile (Entity (Expr)) then
648 Subp := Entity (Expr);
652 Get_First_Interp (Expr, I, It);
653 while Present (It.Nam) loop
654 if Has_Good_Profile (It.Nam) then
659 Get_Next_Interp (I, It);
664 if Present (Subp) then
665 if Is_Abstract_Subprogram (Subp) then
666 Error_Msg_N ("stream subprogram must not be abstract", Expr);
670 Set_Entity (Expr, Subp);
671 Set_Etype (Expr, Etype (Subp));
673 New_Stream_Subprogram (N, U_Ent, Subp, TSS_Nam);
676 Error_Msg_Name_1 := Attr;
677 Error_Msg_N ("incorrect expression for% attribute", Expr);
679 end Analyze_Stream_TSS_Definition;
681 -- Start of processing for Analyze_Attribute_Definition_Clause
684 if Ignore_Rep_Clauses then
685 Rewrite (N, Make_Null_Statement (Sloc (N)));
692 if Rep_Item_Too_Early (Ent, N) then
696 -- Rep clause applies to full view of incomplete type or private type if
697 -- we have one (if not, this is a premature use of the type). However,
698 -- certain semantic checks need to be done on the specified entity (i.e.
699 -- the private view), so we save it in Ent.
701 if Is_Private_Type (Ent)
702 and then Is_Derived_Type (Ent)
703 and then not Is_Tagged_Type (Ent)
704 and then No (Full_View (Ent))
706 -- If this is a private type whose completion is a derivation from
707 -- another private type, there is no full view, and the attribute
708 -- belongs to the type itself, not its underlying parent.
712 elsif Ekind (Ent) = E_Incomplete_Type then
714 -- The attribute applies to the full view, set the entity of the
715 -- attribute definition accordingly.
717 Ent := Underlying_Type (Ent);
719 Set_Entity (Nam, Ent);
722 U_Ent := Underlying_Type (Ent);
725 -- Complete other routine error checks
727 if Etype (Nam) = Any_Type then
730 elsif Scope (Ent) /= Current_Scope then
731 Error_Msg_N ("entity must be declared in this scope", Nam);
734 elsif No (U_Ent) then
737 elsif Is_Type (U_Ent)
738 and then not Is_First_Subtype (U_Ent)
739 and then Id /= Attribute_Object_Size
740 and then Id /= Attribute_Value_Size
741 and then not From_At_Mod (N)
743 Error_Msg_N ("cannot specify attribute for subtype", Nam);
747 -- Switch on particular attribute
755 -- Address attribute definition clause
757 when Attribute_Address => Address : begin
759 -- A little error check, catch for X'Address use X'Address;
761 if Nkind (Nam) = N_Identifier
762 and then Nkind (Expr) = N_Attribute_Reference
763 and then Attribute_Name (Expr) = Name_Address
764 and then Nkind (Prefix (Expr)) = N_Identifier
765 and then Chars (Nam) = Chars (Prefix (Expr))
768 ("address for & is self-referencing", Prefix (Expr), Ent);
772 -- Not that special case, carry on with analysis of expression
774 Analyze_And_Resolve (Expr, RTE (RE_Address));
776 if Present (Address_Clause (U_Ent)) then
777 Error_Msg_N ("address already given for &", Nam);
779 -- Case of address clause for subprogram
781 elsif Is_Subprogram (U_Ent) then
782 if Has_Homonym (U_Ent) then
784 ("address clause cannot be given " &
785 "for overloaded subprogram",
790 -- For subprograms, all address clauses are permitted, and we
791 -- mark the subprogram as having a deferred freeze so that Gigi
792 -- will not elaborate it too soon.
794 -- Above needs more comments, what is too soon about???
796 Set_Has_Delayed_Freeze (U_Ent);
798 -- Case of address clause for entry
800 elsif Ekind (U_Ent) = E_Entry then
801 if Nkind (Parent (N)) = N_Task_Body then
803 ("entry address must be specified in task spec", Nam);
807 -- For entries, we require a constant address
809 Check_Constant_Address_Clause (Expr, U_Ent);
811 -- Special checks for task types
813 if Is_Task_Type (Scope (U_Ent))
814 and then Comes_From_Source (Scope (U_Ent))
817 ("?entry address declared for entry in task type", N);
819 ("\?only one task can be declared of this type", N);
822 -- Entry address clauses are obsolescent
824 Check_Restriction (No_Obsolescent_Features, N);
826 if Warn_On_Obsolescent_Feature then
828 ("attaching interrupt to task entry is an " &
829 "obsolescent feature (RM J.7.1)?", N);
831 ("\use interrupt procedure instead?", N);
834 -- Case of an address clause for a controlled object which we
835 -- consider to be erroneous.
837 elsif Is_Controlled (Etype (U_Ent))
838 or else Has_Controlled_Component (Etype (U_Ent))
841 ("?controlled object& must not be overlaid", Nam, U_Ent);
843 ("\?Program_Error will be raised at run time", Nam);
844 Insert_Action (Declaration_Node (U_Ent),
845 Make_Raise_Program_Error (Loc,
846 Reason => PE_Overlaid_Controlled_Object));
849 -- Case of address clause for a (non-controlled) object
852 Ekind (U_Ent) = E_Variable
854 Ekind (U_Ent) = E_Constant
857 Expr : constant Node_Id := Expression (N);
858 Aent : constant Entity_Id := Address_Aliased_Entity (Expr);
859 Ent_Y : constant Entity_Id := Find_Overlaid_Object (N);
862 -- Exported variables cannot have an address clause,
863 -- because this cancels the effect of the pragma Export
865 if Is_Exported (U_Ent) then
867 ("cannot export object with address clause", Nam);
870 -- Overlaying controlled objects is erroneous
873 and then (Has_Controlled_Component (Etype (Aent))
874 or else Is_Controlled (Etype (Aent)))
877 ("?cannot overlay with controlled object", Expr);
879 ("\?Program_Error will be raised at run time", Expr);
880 Insert_Action (Declaration_Node (U_Ent),
881 Make_Raise_Program_Error (Loc,
882 Reason => PE_Overlaid_Controlled_Object));
886 and then Ekind (U_Ent) = E_Constant
887 and then Ekind (Aent) /= E_Constant
889 Error_Msg_N ("constant overlays a variable?", Expr);
891 elsif Present (Renamed_Object (U_Ent)) then
893 ("address clause not allowed"
894 & " for a renaming declaration (RM 13.1(6))", Nam);
897 -- Imported variables can have an address clause, but then
898 -- the import is pretty meaningless except to suppress
899 -- initializations, so we do not need such variables to
900 -- be statically allocated (and in fact it causes trouble
901 -- if the address clause is a local value).
903 elsif Is_Imported (U_Ent) then
904 Set_Is_Statically_Allocated (U_Ent, False);
907 -- We mark a possible modification of a variable with an
908 -- address clause, since it is likely aliasing is occurring.
910 Note_Possible_Modification (Nam, Sure => False);
912 -- Here we are checking for explicit overlap of one variable
913 -- by another, and if we find this then mark the overlapped
914 -- variable as also being volatile to prevent unwanted
917 if Present (Ent_Y) then
918 Set_Treat_As_Volatile (Ent_Y);
921 -- Legality checks on the address clause for initialized
922 -- objects is deferred until the freeze point, because
923 -- a subsequent pragma might indicate that the object is
924 -- imported and thus not initialized.
926 Set_Has_Delayed_Freeze (U_Ent);
928 if Is_Exported (U_Ent) then
930 ("& cannot be exported if an address clause is given",
933 ("\define and export a variable " &
934 "that holds its address instead",
938 -- Entity has delayed freeze, so we will generate an
939 -- alignment check at the freeze point unless suppressed.
941 if not Range_Checks_Suppressed (U_Ent)
942 and then not Alignment_Checks_Suppressed (U_Ent)
944 Set_Check_Address_Alignment (N);
947 -- Kill the size check code, since we are not allocating
948 -- the variable, it is somewhere else.
950 Kill_Size_Check_Code (U_Ent);
953 -- If the address clause is of the form:
955 -- for Y'Address use X'Address
959 -- Const : constant Address := X'Address;
961 -- for Y'Address use Const;
963 -- then we make an entry in the table for checking the size and
964 -- alignment of the overlaying variable. We defer this check
965 -- till after code generation to take full advantage of the
966 -- annotation done by the back end. This entry is only made if
967 -- we have not already posted a warning about size/alignment
968 -- (some warnings of this type are posted in Checks), and if
969 -- the address clause comes from source.
971 if Address_Clause_Overlay_Warnings
972 and then Comes_From_Source (N)
975 Ent_X : Entity_Id := Empty;
976 Ent_Y : Entity_Id := Empty;
979 Ent_Y := Find_Overlaid_Object (N);
981 if Present (Ent_Y) and then Is_Entity_Name (Name (N)) then
982 Ent_X := Entity (Name (N));
983 Address_Clause_Checks.Append ((N, Ent_X, Ent_Y));
985 -- If variable overlays a constant view, and we are
986 -- warning on overlays, then mark the variable as
987 -- overlaying a constant (we will give warnings later
988 -- if this variable is assigned).
990 if Is_Constant_Object (Ent_Y)
991 and then Ekind (Ent_X) = E_Variable
993 Set_Overlays_Constant (Ent_X);
999 -- Not a valid entity for an address clause
1002 Error_Msg_N ("address cannot be given for &", Nam);
1010 -- Alignment attribute definition clause
1012 when Attribute_Alignment => Alignment_Block : declare
1013 Align : constant Uint := Get_Alignment_Value (Expr);
1018 if not Is_Type (U_Ent)
1019 and then Ekind (U_Ent) /= E_Variable
1020 and then Ekind (U_Ent) /= E_Constant
1022 Error_Msg_N ("alignment cannot be given for &", Nam);
1024 elsif Has_Alignment_Clause (U_Ent) then
1025 Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent));
1026 Error_Msg_N ("alignment clause previously given#", N);
1028 elsif Align /= No_Uint then
1029 Set_Has_Alignment_Clause (U_Ent);
1030 Set_Alignment (U_Ent, Align);
1032 end Alignment_Block;
1038 -- Bit_Order attribute definition clause
1040 when Attribute_Bit_Order => Bit_Order : declare
1042 if not Is_Record_Type (U_Ent) then
1044 ("Bit_Order can only be defined for record type", Nam);
1047 Analyze_And_Resolve (Expr, RTE (RE_Bit_Order));
1049 if Etype (Expr) = Any_Type then
1052 elsif not Is_Static_Expression (Expr) then
1053 Flag_Non_Static_Expr
1054 ("Bit_Order requires static expression!", Expr);
1057 if (Expr_Value (Expr) = 0) /= Bytes_Big_Endian then
1058 Set_Reverse_Bit_Order (U_Ent, True);
1064 --------------------
1065 -- Component_Size --
1066 --------------------
1068 -- Component_Size attribute definition clause
1070 when Attribute_Component_Size => Component_Size_Case : declare
1071 Csize : constant Uint := Static_Integer (Expr);
1074 New_Ctyp : Entity_Id;
1078 if not Is_Array_Type (U_Ent) then
1079 Error_Msg_N ("component size requires array type", Nam);
1083 Btype := Base_Type (U_Ent);
1085 if Has_Component_Size_Clause (Btype) then
1087 ("component size clause for& previously given", Nam);
1089 elsif Csize /= No_Uint then
1090 Check_Size (Expr, Component_Type (Btype), Csize, Biased);
1092 if Has_Aliased_Components (Btype)
1095 and then Csize /= 16
1098 ("component size incorrect for aliased components", N);
1102 -- For the biased case, build a declaration for a subtype
1103 -- that will be used to represent the biased subtype that
1104 -- reflects the biased representation of components. We need
1105 -- this subtype to get proper conversions on referencing
1106 -- elements of the array. Note that component size clauses
1107 -- are ignored in VM mode.
1109 if VM_Target = No_VM then
1112 Make_Defining_Identifier (Loc,
1114 New_External_Name (Chars (U_Ent), 'C', 0, 'T'));
1117 Make_Subtype_Declaration (Loc,
1118 Defining_Identifier => New_Ctyp,
1119 Subtype_Indication =>
1120 New_Occurrence_Of (Component_Type (Btype), Loc));
1122 Set_Parent (Decl, N);
1123 Analyze (Decl, Suppress => All_Checks);
1125 Set_Has_Delayed_Freeze (New_Ctyp, False);
1126 Set_Esize (New_Ctyp, Csize);
1127 Set_RM_Size (New_Ctyp, Csize);
1128 Init_Alignment (New_Ctyp);
1129 Set_Has_Biased_Representation (New_Ctyp, True);
1130 Set_Is_Itype (New_Ctyp, True);
1131 Set_Associated_Node_For_Itype (New_Ctyp, U_Ent);
1133 Set_Component_Type (Btype, New_Ctyp);
1136 Set_Component_Size (Btype, Csize);
1138 -- For VM case, we ignore component size clauses
1141 -- Give a warning unless we are in GNAT mode, in which case
1142 -- the warning is suppressed since it is not useful.
1144 if not GNAT_Mode then
1146 ("?component size ignored in this configuration", N);
1150 Set_Has_Component_Size_Clause (Btype, True);
1151 Set_Has_Non_Standard_Rep (Btype, True);
1153 end Component_Size_Case;
1159 when Attribute_External_Tag => External_Tag :
1161 if not Is_Tagged_Type (U_Ent) then
1162 Error_Msg_N ("should be a tagged type", Nam);
1165 Analyze_And_Resolve (Expr, Standard_String);
1167 if not Is_Static_Expression (Expr) then
1168 Flag_Non_Static_Expr
1169 ("static string required for tag name!", Nam);
1172 if VM_Target = No_VM then
1173 Set_Has_External_Tag_Rep_Clause (U_Ent);
1174 elsif not Inspector_Mode then
1175 Error_Msg_Name_1 := Attr;
1177 ("% attribute unsupported in this configuration", Nam);
1180 if not Is_Library_Level_Entity (U_Ent) then
1182 ("?non-unique external tag supplied for &", N, U_Ent);
1184 ("?\same external tag applies to all subprogram calls", N);
1186 ("?\corresponding internal tag cannot be obtained", N);
1194 when Attribute_Input =>
1195 Analyze_Stream_TSS_Definition (TSS_Stream_Input);
1196 Set_Has_Specified_Stream_Input (Ent);
1202 -- Machine radix attribute definition clause
1204 when Attribute_Machine_Radix => Machine_Radix : declare
1205 Radix : constant Uint := Static_Integer (Expr);
1208 if not Is_Decimal_Fixed_Point_Type (U_Ent) then
1209 Error_Msg_N ("decimal fixed-point type expected for &", Nam);
1211 elsif Has_Machine_Radix_Clause (U_Ent) then
1212 Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent));
1213 Error_Msg_N ("machine radix clause previously given#", N);
1215 elsif Radix /= No_Uint then
1216 Set_Has_Machine_Radix_Clause (U_Ent);
1217 Set_Has_Non_Standard_Rep (Base_Type (U_Ent));
1221 elsif Radix = 10 then
1222 Set_Machine_Radix_10 (U_Ent);
1224 Error_Msg_N ("machine radix value must be 2 or 10", Expr);
1233 -- Object_Size attribute definition clause
1235 when Attribute_Object_Size => Object_Size : declare
1236 Size : constant Uint := Static_Integer (Expr);
1239 pragma Warnings (Off, Biased);
1242 if not Is_Type (U_Ent) then
1243 Error_Msg_N ("Object_Size cannot be given for &", Nam);
1245 elsif Has_Object_Size_Clause (U_Ent) then
1246 Error_Msg_N ("Object_Size already given for &", Nam);
1249 Check_Size (Expr, U_Ent, Size, Biased);
1257 UI_Mod (Size, 64) /= 0
1260 ("Object_Size must be 8, 16, 32, or multiple of 64",
1264 Set_Esize (U_Ent, Size);
1265 Set_Has_Object_Size_Clause (U_Ent);
1266 Alignment_Check_For_Esize_Change (U_Ent);
1274 when Attribute_Output =>
1275 Analyze_Stream_TSS_Definition (TSS_Stream_Output);
1276 Set_Has_Specified_Stream_Output (Ent);
1282 when Attribute_Read =>
1283 Analyze_Stream_TSS_Definition (TSS_Stream_Read);
1284 Set_Has_Specified_Stream_Read (Ent);
1290 -- Size attribute definition clause
1292 when Attribute_Size => Size : declare
1293 Size : constant Uint := Static_Integer (Expr);
1300 if Has_Size_Clause (U_Ent) then
1301 Error_Msg_N ("size already given for &", Nam);
1303 elsif not Is_Type (U_Ent)
1304 and then Ekind (U_Ent) /= E_Variable
1305 and then Ekind (U_Ent) /= E_Constant
1307 Error_Msg_N ("size cannot be given for &", Nam);
1309 elsif Is_Array_Type (U_Ent)
1310 and then not Is_Constrained (U_Ent)
1313 ("size cannot be given for unconstrained array", Nam);
1315 elsif Size /= No_Uint then
1316 if Is_Type (U_Ent) then
1319 Etyp := Etype (U_Ent);
1322 -- Check size, note that Gigi is in charge of checking that the
1323 -- size of an array or record type is OK. Also we do not check
1324 -- the size in the ordinary fixed-point case, since it is too
1325 -- early to do so (there may be subsequent small clause that
1326 -- affects the size). We can check the size if a small clause
1327 -- has already been given.
1329 if not Is_Ordinary_Fixed_Point_Type (U_Ent)
1330 or else Has_Small_Clause (U_Ent)
1332 Check_Size (Expr, Etyp, Size, Biased);
1333 Set_Has_Biased_Representation (U_Ent, Biased);
1336 -- For types set RM_Size and Esize if possible
1338 if Is_Type (U_Ent) then
1339 Set_RM_Size (U_Ent, Size);
1341 -- For scalar types, increase Object_Size to power of 2, but
1342 -- not less than a storage unit in any case (i.e., normally
1343 -- this means it will be byte addressable).
1345 if Is_Scalar_Type (U_Ent) then
1346 if Size <= System_Storage_Unit then
1347 Init_Esize (U_Ent, System_Storage_Unit);
1348 elsif Size <= 16 then
1349 Init_Esize (U_Ent, 16);
1350 elsif Size <= 32 then
1351 Init_Esize (U_Ent, 32);
1353 Set_Esize (U_Ent, (Size + 63) / 64 * 64);
1356 -- For all other types, object size = value size. The
1357 -- backend will adjust as needed.
1360 Set_Esize (U_Ent, Size);
1363 Alignment_Check_For_Esize_Change (U_Ent);
1365 -- For objects, set Esize only
1368 if Is_Elementary_Type (Etyp) then
1369 if Size /= System_Storage_Unit
1371 Size /= System_Storage_Unit * 2
1373 Size /= System_Storage_Unit * 4
1375 Size /= System_Storage_Unit * 8
1377 Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit);
1378 Error_Msg_Uint_2 := Error_Msg_Uint_1 * 8;
1380 ("size for primitive object must be a power of 2"
1381 & " in the range ^-^", N);
1385 Set_Esize (U_Ent, Size);
1388 Set_Has_Size_Clause (U_Ent);
1396 -- Small attribute definition clause
1398 when Attribute_Small => Small : declare
1399 Implicit_Base : constant Entity_Id := Base_Type (U_Ent);
1403 Analyze_And_Resolve (Expr, Any_Real);
1405 if Etype (Expr) = Any_Type then
1408 elsif not Is_Static_Expression (Expr) then
1409 Flag_Non_Static_Expr
1410 ("small requires static expression!", Expr);
1414 Small := Expr_Value_R (Expr);
1416 if Small <= Ureal_0 then
1417 Error_Msg_N ("small value must be greater than zero", Expr);
1423 if not Is_Ordinary_Fixed_Point_Type (U_Ent) then
1425 ("small requires an ordinary fixed point type", Nam);
1427 elsif Has_Small_Clause (U_Ent) then
1428 Error_Msg_N ("small already given for &", Nam);
1430 elsif Small > Delta_Value (U_Ent) then
1432 ("small value must not be greater then delta value", Nam);
1435 Set_Small_Value (U_Ent, Small);
1436 Set_Small_Value (Implicit_Base, Small);
1437 Set_Has_Small_Clause (U_Ent);
1438 Set_Has_Small_Clause (Implicit_Base);
1439 Set_Has_Non_Standard_Rep (Implicit_Base);
1447 -- Storage_Pool attribute definition clause
1449 when Attribute_Storage_Pool => Storage_Pool : declare
1454 if Ekind (U_Ent) = E_Access_Subprogram_Type then
1456 ("storage pool cannot be given for access-to-subprogram type",
1460 elsif Ekind (U_Ent) /= E_Access_Type
1461 and then Ekind (U_Ent) /= E_General_Access_Type
1464 ("storage pool can only be given for access types", Nam);
1467 elsif Is_Derived_Type (U_Ent) then
1469 ("storage pool cannot be given for a derived access type",
1472 elsif Has_Storage_Size_Clause (U_Ent) then
1473 Error_Msg_N ("storage size already given for &", Nam);
1476 elsif Present (Associated_Storage_Pool (U_Ent)) then
1477 Error_Msg_N ("storage pool already given for &", Nam);
1482 (Expr, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
1484 if Nkind (Expr) = N_Type_Conversion then
1485 T := Etype (Expression (Expr));
1490 -- The Stack_Bounded_Pool is used internally for implementing
1491 -- access types with a Storage_Size. Since it only work
1492 -- properly when used on one specific type, we need to check
1493 -- that it is not hijacked improperly:
1494 -- type T is access Integer;
1495 -- for T'Storage_Size use n;
1496 -- type Q is access Float;
1497 -- for Q'Storage_Size use T'Storage_Size; -- incorrect
1499 if RTE_Available (RE_Stack_Bounded_Pool)
1500 and then Base_Type (T) = RTE (RE_Stack_Bounded_Pool)
1502 Error_Msg_N ("non-shareable internal Pool", Expr);
1506 -- If the argument is a name that is not an entity name, then
1507 -- we construct a renaming operation to define an entity of
1508 -- type storage pool.
1510 if not Is_Entity_Name (Expr)
1511 and then Is_Object_Reference (Expr)
1514 Make_Defining_Identifier (Loc,
1515 Chars => New_Internal_Name ('P'));
1518 Rnode : constant Node_Id :=
1519 Make_Object_Renaming_Declaration (Loc,
1520 Defining_Identifier => Pool,
1522 New_Occurrence_Of (Etype (Expr), Loc),
1526 Insert_Before (N, Rnode);
1528 Set_Associated_Storage_Pool (U_Ent, Pool);
1531 elsif Is_Entity_Name (Expr) then
1532 Pool := Entity (Expr);
1534 -- If pool is a renamed object, get original one. This can
1535 -- happen with an explicit renaming, and within instances.
1537 while Present (Renamed_Object (Pool))
1538 and then Is_Entity_Name (Renamed_Object (Pool))
1540 Pool := Entity (Renamed_Object (Pool));
1543 if Present (Renamed_Object (Pool))
1544 and then Nkind (Renamed_Object (Pool)) = N_Type_Conversion
1545 and then Is_Entity_Name (Expression (Renamed_Object (Pool)))
1547 Pool := Entity (Expression (Renamed_Object (Pool)));
1550 Set_Associated_Storage_Pool (U_Ent, Pool);
1552 elsif Nkind (Expr) = N_Type_Conversion
1553 and then Is_Entity_Name (Expression (Expr))
1554 and then Nkind (Original_Node (Expr)) = N_Attribute_Reference
1556 Pool := Entity (Expression (Expr));
1557 Set_Associated_Storage_Pool (U_Ent, Pool);
1560 Error_Msg_N ("incorrect reference to a Storage Pool", Expr);
1569 -- Storage_Size attribute definition clause
1571 when Attribute_Storage_Size => Storage_Size : declare
1572 Btype : constant Entity_Id := Base_Type (U_Ent);
1576 if Is_Task_Type (U_Ent) then
1577 Check_Restriction (No_Obsolescent_Features, N);
1579 if Warn_On_Obsolescent_Feature then
1581 ("storage size clause for task is an " &
1582 "obsolescent feature (RM J.9)?", N);
1584 ("\use Storage_Size pragma instead?", N);
1590 if not Is_Access_Type (U_Ent)
1591 and then Ekind (U_Ent) /= E_Task_Type
1593 Error_Msg_N ("storage size cannot be given for &", Nam);
1595 elsif Is_Access_Type (U_Ent) and Is_Derived_Type (U_Ent) then
1597 ("storage size cannot be given for a derived access type",
1600 elsif Has_Storage_Size_Clause (Btype) then
1601 Error_Msg_N ("storage size already given for &", Nam);
1604 Analyze_And_Resolve (Expr, Any_Integer);
1606 if Is_Access_Type (U_Ent) then
1607 if Present (Associated_Storage_Pool (U_Ent)) then
1608 Error_Msg_N ("storage pool already given for &", Nam);
1612 if Compile_Time_Known_Value (Expr)
1613 and then Expr_Value (Expr) = 0
1615 Set_No_Pool_Assigned (Btype);
1618 else -- Is_Task_Type (U_Ent)
1619 Sprag := Get_Rep_Pragma (Btype, Name_Storage_Size);
1621 if Present (Sprag) then
1622 Error_Msg_Sloc := Sloc (Sprag);
1624 ("Storage_Size already specified#", Nam);
1629 Set_Has_Storage_Size_Clause (Btype);
1637 when Attribute_Stream_Size => Stream_Size : declare
1638 Size : constant Uint := Static_Integer (Expr);
1641 if Ada_Version <= Ada_95 then
1642 Check_Restriction (No_Implementation_Attributes, N);
1645 if Has_Stream_Size_Clause (U_Ent) then
1646 Error_Msg_N ("Stream_Size already given for &", Nam);
1648 elsif Is_Elementary_Type (U_Ent) then
1649 if Size /= System_Storage_Unit
1651 Size /= System_Storage_Unit * 2
1653 Size /= System_Storage_Unit * 4
1655 Size /= System_Storage_Unit * 8
1657 Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit);
1659 ("stream size for elementary type must be a"
1660 & " power of 2 and at least ^", N);
1662 elsif RM_Size (U_Ent) > Size then
1663 Error_Msg_Uint_1 := RM_Size (U_Ent);
1665 ("stream size for elementary type must be a"
1666 & " power of 2 and at least ^", N);
1669 Set_Has_Stream_Size_Clause (U_Ent);
1672 Error_Msg_N ("Stream_Size cannot be given for &", Nam);
1680 -- Value_Size attribute definition clause
1682 when Attribute_Value_Size => Value_Size : declare
1683 Size : constant Uint := Static_Integer (Expr);
1687 if not Is_Type (U_Ent) then
1688 Error_Msg_N ("Value_Size cannot be given for &", Nam);
1691 (Get_Attribute_Definition_Clause
1692 (U_Ent, Attribute_Value_Size))
1694 Error_Msg_N ("Value_Size already given for &", Nam);
1696 elsif Is_Array_Type (U_Ent)
1697 and then not Is_Constrained (U_Ent)
1700 ("Value_Size cannot be given for unconstrained array", Nam);
1703 if Is_Elementary_Type (U_Ent) then
1704 Check_Size (Expr, U_Ent, Size, Biased);
1705 Set_Has_Biased_Representation (U_Ent, Biased);
1708 Set_RM_Size (U_Ent, Size);
1716 when Attribute_Write =>
1717 Analyze_Stream_TSS_Definition (TSS_Stream_Write);
1718 Set_Has_Specified_Stream_Write (Ent);
1720 -- All other attributes cannot be set
1724 ("attribute& cannot be set with definition clause", N);
1727 -- The test for the type being frozen must be performed after
1728 -- any expression the clause has been analyzed since the expression
1729 -- itself might cause freezing that makes the clause illegal.
1731 if Rep_Item_Too_Late (U_Ent, N, FOnly) then
1734 end Analyze_Attribute_Definition_Clause;
1736 ----------------------------
1737 -- Analyze_Code_Statement --
1738 ----------------------------
1740 procedure Analyze_Code_Statement (N : Node_Id) is
1741 HSS : constant Node_Id := Parent (N);
1742 SBody : constant Node_Id := Parent (HSS);
1743 Subp : constant Entity_Id := Current_Scope;
1750 -- Analyze and check we get right type, note that this implements the
1751 -- requirement (RM 13.8(1)) that Machine_Code be with'ed, since that
1752 -- is the only way that Asm_Insn could possibly be visible.
1754 Analyze_And_Resolve (Expression (N));
1756 if Etype (Expression (N)) = Any_Type then
1758 elsif Etype (Expression (N)) /= RTE (RE_Asm_Insn) then
1759 Error_Msg_N ("incorrect type for code statement", N);
1763 Check_Code_Statement (N);
1765 -- Make sure we appear in the handled statement sequence of a
1766 -- subprogram (RM 13.8(3)).
1768 if Nkind (HSS) /= N_Handled_Sequence_Of_Statements
1769 or else Nkind (SBody) /= N_Subprogram_Body
1772 ("code statement can only appear in body of subprogram", N);
1776 -- Do remaining checks (RM 13.8(3)) if not already done
1778 if not Is_Machine_Code_Subprogram (Subp) then
1779 Set_Is_Machine_Code_Subprogram (Subp);
1781 -- No exception handlers allowed
1783 if Present (Exception_Handlers (HSS)) then
1785 ("exception handlers not permitted in machine code subprogram",
1786 First (Exception_Handlers (HSS)));
1789 -- No declarations other than use clauses and pragmas (we allow
1790 -- certain internally generated declarations as well).
1792 Decl := First (Declarations (SBody));
1793 while Present (Decl) loop
1794 DeclO := Original_Node (Decl);
1795 if Comes_From_Source (DeclO)
1796 and not Nkind_In (DeclO, N_Pragma,
1797 N_Use_Package_Clause,
1799 N_Implicit_Label_Declaration)
1802 ("this declaration not allowed in machine code subprogram",
1809 -- No statements other than code statements, pragmas, and labels.
1810 -- Again we allow certain internally generated statements.
1812 Stmt := First (Statements (HSS));
1813 while Present (Stmt) loop
1814 StmtO := Original_Node (Stmt);
1815 if Comes_From_Source (StmtO)
1816 and then not Nkind_In (StmtO, N_Pragma,
1821 ("this statement is not allowed in machine code subprogram",
1828 end Analyze_Code_Statement;
1830 -----------------------------------------------
1831 -- Analyze_Enumeration_Representation_Clause --
1832 -----------------------------------------------
1834 procedure Analyze_Enumeration_Representation_Clause (N : Node_Id) is
1835 Ident : constant Node_Id := Identifier (N);
1836 Aggr : constant Node_Id := Array_Aggregate (N);
1837 Enumtype : Entity_Id;
1843 Err : Boolean := False;
1845 Lo : constant Uint := Expr_Value (Type_Low_Bound (Universal_Integer));
1846 Hi : constant Uint := Expr_Value (Type_High_Bound (Universal_Integer));
1851 if Ignore_Rep_Clauses then
1855 -- First some basic error checks
1858 Enumtype := Entity (Ident);
1860 if Enumtype = Any_Type
1861 or else Rep_Item_Too_Early (Enumtype, N)
1865 Enumtype := Underlying_Type (Enumtype);
1868 if not Is_Enumeration_Type (Enumtype) then
1870 ("enumeration type required, found}",
1871 Ident, First_Subtype (Enumtype));
1875 -- Ignore rep clause on generic actual type. This will already have
1876 -- been flagged on the template as an error, and this is the safest
1877 -- way to ensure we don't get a junk cascaded message in the instance.
1879 if Is_Generic_Actual_Type (Enumtype) then
1882 -- Type must be in current scope
1884 elsif Scope (Enumtype) /= Current_Scope then
1885 Error_Msg_N ("type must be declared in this scope", Ident);
1888 -- Type must be a first subtype
1890 elsif not Is_First_Subtype (Enumtype) then
1891 Error_Msg_N ("cannot give enumeration rep clause for subtype", N);
1894 -- Ignore duplicate rep clause
1896 elsif Has_Enumeration_Rep_Clause (Enumtype) then
1897 Error_Msg_N ("duplicate enumeration rep clause ignored", N);
1900 -- Don't allow rep clause for standard [wide_[wide_]]character
1902 elsif Is_Standard_Character_Type (Enumtype) then
1903 Error_Msg_N ("enumeration rep clause not allowed for this type", N);
1906 -- Check that the expression is a proper aggregate (no parentheses)
1908 elsif Paren_Count (Aggr) /= 0 then
1910 ("extra parentheses surrounding aggregate not allowed",
1914 -- All tests passed, so set rep clause in place
1917 Set_Has_Enumeration_Rep_Clause (Enumtype);
1918 Set_Has_Enumeration_Rep_Clause (Base_Type (Enumtype));
1921 -- Now we process the aggregate. Note that we don't use the normal
1922 -- aggregate code for this purpose, because we don't want any of the
1923 -- normal expansion activities, and a number of special semantic
1924 -- rules apply (including the component type being any integer type)
1926 Elit := First_Literal (Enumtype);
1928 -- First the positional entries if any
1930 if Present (Expressions (Aggr)) then
1931 Expr := First (Expressions (Aggr));
1932 while Present (Expr) loop
1934 Error_Msg_N ("too many entries in aggregate", Expr);
1938 Val := Static_Integer (Expr);
1940 -- Err signals that we found some incorrect entries processing
1941 -- the list. The final checks for completeness and ordering are
1942 -- skipped in this case.
1944 if Val = No_Uint then
1946 elsif Val < Lo or else Hi < Val then
1947 Error_Msg_N ("value outside permitted range", Expr);
1951 Set_Enumeration_Rep (Elit, Val);
1952 Set_Enumeration_Rep_Expr (Elit, Expr);
1958 -- Now process the named entries if present
1960 if Present (Component_Associations (Aggr)) then
1961 Assoc := First (Component_Associations (Aggr));
1962 while Present (Assoc) loop
1963 Choice := First (Choices (Assoc));
1965 if Present (Next (Choice)) then
1967 ("multiple choice not allowed here", Next (Choice));
1971 if Nkind (Choice) = N_Others_Choice then
1972 Error_Msg_N ("others choice not allowed here", Choice);
1975 elsif Nkind (Choice) = N_Range then
1976 -- ??? should allow zero/one element range here
1977 Error_Msg_N ("range not allowed here", Choice);
1981 Analyze_And_Resolve (Choice, Enumtype);
1983 if Is_Entity_Name (Choice)
1984 and then Is_Type (Entity (Choice))
1986 Error_Msg_N ("subtype name not allowed here", Choice);
1988 -- ??? should allow static subtype with zero/one entry
1990 elsif Etype (Choice) = Base_Type (Enumtype) then
1991 if not Is_Static_Expression (Choice) then
1992 Flag_Non_Static_Expr
1993 ("non-static expression used for choice!", Choice);
1997 Elit := Expr_Value_E (Choice);
1999 if Present (Enumeration_Rep_Expr (Elit)) then
2000 Error_Msg_Sloc := Sloc (Enumeration_Rep_Expr (Elit));
2002 ("representation for& previously given#",
2007 Set_Enumeration_Rep_Expr (Elit, Choice);
2009 Expr := Expression (Assoc);
2010 Val := Static_Integer (Expr);
2012 if Val = No_Uint then
2015 elsif Val < Lo or else Hi < Val then
2016 Error_Msg_N ("value outside permitted range", Expr);
2020 Set_Enumeration_Rep (Elit, Val);
2029 -- Aggregate is fully processed. Now we check that a full set of
2030 -- representations was given, and that they are in range and in order.
2031 -- These checks are only done if no other errors occurred.
2037 Elit := First_Literal (Enumtype);
2038 while Present (Elit) loop
2039 if No (Enumeration_Rep_Expr (Elit)) then
2040 Error_Msg_NE ("missing representation for&!", N, Elit);
2043 Val := Enumeration_Rep (Elit);
2045 if Min = No_Uint then
2049 if Val /= No_Uint then
2050 if Max /= No_Uint and then Val <= Max then
2052 ("enumeration value for& not ordered!",
2053 Enumeration_Rep_Expr (Elit), Elit);
2059 -- If there is at least one literal whose representation
2060 -- is not equal to the Pos value, then note that this
2061 -- enumeration type has a non-standard representation.
2063 if Val /= Enumeration_Pos (Elit) then
2064 Set_Has_Non_Standard_Rep (Base_Type (Enumtype));
2071 -- Now set proper size information
2074 Minsize : Uint := UI_From_Int (Minimum_Size (Enumtype));
2077 if Has_Size_Clause (Enumtype) then
2078 if Esize (Enumtype) >= Minsize then
2083 UI_From_Int (Minimum_Size (Enumtype, Biased => True));
2085 if Esize (Enumtype) < Minsize then
2086 Error_Msg_N ("previously given size is too small", N);
2089 Set_Has_Biased_Representation (Enumtype);
2094 Set_RM_Size (Enumtype, Minsize);
2095 Set_Enum_Esize (Enumtype);
2098 Set_RM_Size (Base_Type (Enumtype), RM_Size (Enumtype));
2099 Set_Esize (Base_Type (Enumtype), Esize (Enumtype));
2100 Set_Alignment (Base_Type (Enumtype), Alignment (Enumtype));
2104 -- We repeat the too late test in case it froze itself!
2106 if Rep_Item_Too_Late (Enumtype, N) then
2109 end Analyze_Enumeration_Representation_Clause;
2111 ----------------------------
2112 -- Analyze_Free_Statement --
2113 ----------------------------
2115 procedure Analyze_Free_Statement (N : Node_Id) is
2117 Analyze (Expression (N));
2118 end Analyze_Free_Statement;
2120 ------------------------------------------
2121 -- Analyze_Record_Representation_Clause --
2122 ------------------------------------------
2124 procedure Analyze_Record_Representation_Clause (N : Node_Id) is
2125 Loc : constant Source_Ptr := Sloc (N);
2126 Ident : constant Node_Id := Identifier (N);
2127 Rectype : Entity_Id;
2133 Hbit : Uint := Uint_0;
2138 Max_Bit_So_Far : Uint;
2139 -- Records the maximum bit position so far. If all field positions
2140 -- are monotonically increasing, then we can skip the circuit for
2141 -- checking for overlap, since no overlap is possible.
2143 Overlap_Check_Required : Boolean;
2144 -- Used to keep track of whether or not an overlap check is required
2146 Ccount : Natural := 0;
2147 -- Number of component clauses in record rep clause
2149 CR_Pragma : Node_Id := Empty;
2150 -- Points to N_Pragma node if Complete_Representation pragma present
2153 if Ignore_Rep_Clauses then
2158 Rectype := Entity (Ident);
2160 if Rectype = Any_Type
2161 or else Rep_Item_Too_Early (Rectype, N)
2165 Rectype := Underlying_Type (Rectype);
2168 -- First some basic error checks
2170 if not Is_Record_Type (Rectype) then
2172 ("record type required, found}", Ident, First_Subtype (Rectype));
2175 elsif Is_Unchecked_Union (Rectype) then
2177 ("record rep clause not allowed for Unchecked_Union", N);
2179 elsif Scope (Rectype) /= Current_Scope then
2180 Error_Msg_N ("type must be declared in this scope", N);
2183 elsif not Is_First_Subtype (Rectype) then
2184 Error_Msg_N ("cannot give record rep clause for subtype", N);
2187 elsif Has_Record_Rep_Clause (Rectype) then
2188 Error_Msg_N ("duplicate record rep clause ignored", N);
2191 elsif Rep_Item_Too_Late (Rectype, N) then
2195 if Present (Mod_Clause (N)) then
2197 Loc : constant Source_Ptr := Sloc (N);
2198 M : constant Node_Id := Mod_Clause (N);
2199 P : constant List_Id := Pragmas_Before (M);
2203 pragma Warnings (Off, Mod_Val);
2206 Check_Restriction (No_Obsolescent_Features, Mod_Clause (N));
2208 if Warn_On_Obsolescent_Feature then
2210 ("mod clause is an obsolescent feature (RM J.8)?", N);
2212 ("\use alignment attribute definition clause instead?", N);
2219 -- In ASIS_Mode mode, expansion is disabled, but we must convert
2220 -- the Mod clause into an alignment clause anyway, so that the
2221 -- back-end can compute and back-annotate properly the size and
2222 -- alignment of types that may include this record.
2224 -- This seems dubious, this destroys the source tree in a manner
2225 -- not detectable by ASIS ???
2227 if Operating_Mode = Check_Semantics
2231 Make_Attribute_Definition_Clause (Loc,
2232 Name => New_Reference_To (Base_Type (Rectype), Loc),
2233 Chars => Name_Alignment,
2234 Expression => Relocate_Node (Expression (M)));
2236 Set_From_At_Mod (AtM_Nod);
2237 Insert_After (N, AtM_Nod);
2238 Mod_Val := Get_Alignment_Value (Expression (AtM_Nod));
2239 Set_Mod_Clause (N, Empty);
2242 -- Get the alignment value to perform error checking
2244 Mod_Val := Get_Alignment_Value (Expression (M));
2250 -- For untagged types, clear any existing component clauses for the
2251 -- type. If the type is derived, this is what allows us to override
2252 -- a rep clause for the parent. For type extensions, the representation
2253 -- of the inherited components is inherited, so we want to keep previous
2254 -- component clauses for completeness.
2256 if not Is_Tagged_Type (Rectype) then
2257 Comp := First_Component_Or_Discriminant (Rectype);
2258 while Present (Comp) loop
2259 Set_Component_Clause (Comp, Empty);
2260 Next_Component_Or_Discriminant (Comp);
2264 -- All done if no component clauses
2266 CC := First (Component_Clauses (N));
2272 -- If a tag is present, then create a component clause that places it
2273 -- at the start of the record (otherwise gigi may place it after other
2274 -- fields that have rep clauses).
2276 Fent := First_Entity (Rectype);
2278 if Nkind (Fent) = N_Defining_Identifier
2279 and then Chars (Fent) = Name_uTag
2281 Set_Component_Bit_Offset (Fent, Uint_0);
2282 Set_Normalized_Position (Fent, Uint_0);
2283 Set_Normalized_First_Bit (Fent, Uint_0);
2284 Set_Normalized_Position_Max (Fent, Uint_0);
2285 Init_Esize (Fent, System_Address_Size);
2287 Set_Component_Clause (Fent,
2288 Make_Component_Clause (Loc,
2290 Make_Identifier (Loc,
2291 Chars => Name_uTag),
2294 Make_Integer_Literal (Loc,
2298 Make_Integer_Literal (Loc,
2302 Make_Integer_Literal (Loc,
2303 UI_From_Int (System_Address_Size))));
2305 Ccount := Ccount + 1;
2308 -- A representation like this applies to the base type
2310 Set_Has_Record_Rep_Clause (Base_Type (Rectype));
2311 Set_Has_Non_Standard_Rep (Base_Type (Rectype));
2312 Set_Has_Specified_Layout (Base_Type (Rectype));
2314 Max_Bit_So_Far := Uint_Minus_1;
2315 Overlap_Check_Required := False;
2317 -- Process the component clauses
2319 while Present (CC) loop
2323 if Nkind (CC) = N_Pragma then
2326 -- The only pragma of interest is Complete_Representation
2328 if Pragma_Name (CC) = Name_Complete_Representation then
2332 -- Processing for real component clause
2335 Ccount := Ccount + 1;
2336 Posit := Static_Integer (Position (CC));
2337 Fbit := Static_Integer (First_Bit (CC));
2338 Lbit := Static_Integer (Last_Bit (CC));
2341 and then Fbit /= No_Uint
2342 and then Lbit /= No_Uint
2346 ("position cannot be negative", Position (CC));
2350 ("first bit cannot be negative", First_Bit (CC));
2352 -- The Last_Bit specified in a component clause must not be
2353 -- less than the First_Bit minus one (RM-13.5.1(10)).
2355 elsif Lbit < Fbit - 1 then
2357 ("last bit cannot be less than first bit minus one",
2360 -- Values look OK, so find the corresponding record component
2361 -- Even though the syntax allows an attribute reference for
2362 -- implementation-defined components, GNAT does not allow the
2363 -- tag to get an explicit position.
2365 elsif Nkind (Component_Name (CC)) = N_Attribute_Reference then
2366 if Attribute_Name (Component_Name (CC)) = Name_Tag then
2367 Error_Msg_N ("position of tag cannot be specified", CC);
2369 Error_Msg_N ("illegal component name", CC);
2373 Comp := First_Entity (Rectype);
2374 while Present (Comp) loop
2375 exit when Chars (Comp) = Chars (Component_Name (CC));
2381 -- Maybe component of base type that is absent from
2382 -- statically constrained first subtype.
2384 Comp := First_Entity (Base_Type (Rectype));
2385 while Present (Comp) loop
2386 exit when Chars (Comp) = Chars (Component_Name (CC));
2393 ("component clause is for non-existent field", CC);
2395 elsif Present (Component_Clause (Comp)) then
2397 -- Diagnose duplicate rep clause, or check consistency
2398 -- if this is an inherited component. In a double fault,
2399 -- there may be a duplicate inconsistent clause for an
2400 -- inherited component.
2402 if Scope (Original_Record_Component (Comp)) = Rectype
2403 or else Parent (Component_Clause (Comp)) = N
2405 Error_Msg_Sloc := Sloc (Component_Clause (Comp));
2406 Error_Msg_N ("component clause previously given#", CC);
2410 Rep1 : constant Node_Id := Component_Clause (Comp);
2412 if Intval (Position (Rep1)) /=
2413 Intval (Position (CC))
2414 or else Intval (First_Bit (Rep1)) /=
2415 Intval (First_Bit (CC))
2416 or else Intval (Last_Bit (Rep1)) /=
2417 Intval (Last_Bit (CC))
2419 Error_Msg_N ("component clause inconsistent "
2420 & "with representation of ancestor", CC);
2421 elsif Warn_On_Redundant_Constructs then
2422 Error_Msg_N ("?redundant component clause "
2423 & "for inherited component!", CC);
2429 -- Make reference for field in record rep clause and set
2430 -- appropriate entity field in the field identifier.
2433 (Comp, Component_Name (CC), Set_Ref => False);
2434 Set_Entity (Component_Name (CC), Comp);
2436 -- Update Fbit and Lbit to the actual bit number
2438 Fbit := Fbit + UI_From_Int (SSU) * Posit;
2439 Lbit := Lbit + UI_From_Int (SSU) * Posit;
2441 if Fbit <= Max_Bit_So_Far then
2442 Overlap_Check_Required := True;
2444 Max_Bit_So_Far := Lbit;
2447 if Has_Size_Clause (Rectype)
2448 and then Esize (Rectype) <= Lbit
2451 ("bit number out of range of specified size",
2454 Set_Component_Clause (Comp, CC);
2455 Set_Component_Bit_Offset (Comp, Fbit);
2456 Set_Esize (Comp, 1 + (Lbit - Fbit));
2457 Set_Normalized_First_Bit (Comp, Fbit mod SSU);
2458 Set_Normalized_Position (Comp, Fbit / SSU);
2460 Set_Normalized_Position_Max
2461 (Fent, Normalized_Position (Fent));
2463 if Is_Tagged_Type (Rectype)
2464 and then Fbit < System_Address_Size
2467 ("component overlaps tag field of&",
2471 -- This information is also set in the corresponding
2472 -- component of the base type, found by accessing the
2473 -- Original_Record_Component link if it is present.
2475 Ocomp := Original_Record_Component (Comp);
2482 (Component_Name (CC),
2487 Set_Has_Biased_Representation (Comp, Biased);
2489 if Present (Ocomp) then
2490 Set_Component_Clause (Ocomp, CC);
2491 Set_Component_Bit_Offset (Ocomp, Fbit);
2492 Set_Normalized_First_Bit (Ocomp, Fbit mod SSU);
2493 Set_Normalized_Position (Ocomp, Fbit / SSU);
2494 Set_Esize (Ocomp, 1 + (Lbit - Fbit));
2496 Set_Normalized_Position_Max
2497 (Ocomp, Normalized_Position (Ocomp));
2499 Set_Has_Biased_Representation
2500 (Ocomp, Has_Biased_Representation (Comp));
2503 if Esize (Comp) < 0 then
2504 Error_Msg_N ("component size is negative", CC);
2515 -- Now that we have processed all the component clauses, check for
2516 -- overlap. We have to leave this till last, since the components can
2517 -- appear in any arbitrary order in the representation clause.
2519 -- We do not need this check if all specified ranges were monotonic,
2520 -- as recorded by Overlap_Check_Required being False at this stage.
2522 -- This first section checks if there are any overlapping entries at
2523 -- all. It does this by sorting all entries and then seeing if there are
2524 -- any overlaps. If there are none, then that is decisive, but if there
2525 -- are overlaps, they may still be OK (they may result from fields in
2526 -- different variants).
2528 if Overlap_Check_Required then
2529 Overlap_Check1 : declare
2531 OC_Fbit : array (0 .. Ccount) of Uint;
2532 -- First-bit values for component clauses, the value is the offset
2533 -- of the first bit of the field from start of record. The zero
2534 -- entry is for use in sorting.
2536 OC_Lbit : array (0 .. Ccount) of Uint;
2537 -- Last-bit values for component clauses, the value is the offset
2538 -- of the last bit of the field from start of record. The zero
2539 -- entry is for use in sorting.
2541 OC_Count : Natural := 0;
2542 -- Count of entries in OC_Fbit and OC_Lbit
2544 function OC_Lt (Op1, Op2 : Natural) return Boolean;
2545 -- Compare routine for Sort
2547 procedure OC_Move (From : Natural; To : Natural);
2548 -- Move routine for Sort
2550 package Sorting is new GNAT.Heap_Sort_G (OC_Move, OC_Lt);
2552 function OC_Lt (Op1, Op2 : Natural) return Boolean is
2554 return OC_Fbit (Op1) < OC_Fbit (Op2);
2557 procedure OC_Move (From : Natural; To : Natural) is
2559 OC_Fbit (To) := OC_Fbit (From);
2560 OC_Lbit (To) := OC_Lbit (From);
2564 CC := First (Component_Clauses (N));
2565 while Present (CC) loop
2566 if Nkind (CC) /= N_Pragma then
2567 Posit := Static_Integer (Position (CC));
2568 Fbit := Static_Integer (First_Bit (CC));
2569 Lbit := Static_Integer (Last_Bit (CC));
2572 and then Fbit /= No_Uint
2573 and then Lbit /= No_Uint
2575 OC_Count := OC_Count + 1;
2576 Posit := Posit * SSU;
2577 OC_Fbit (OC_Count) := Fbit + Posit;
2578 OC_Lbit (OC_Count) := Lbit + Posit;
2585 Sorting.Sort (OC_Count);
2587 Overlap_Check_Required := False;
2588 for J in 1 .. OC_Count - 1 loop
2589 if OC_Lbit (J) >= OC_Fbit (J + 1) then
2590 Overlap_Check_Required := True;
2597 -- If Overlap_Check_Required is still True, then we have to do the full
2598 -- scale overlap check, since we have at least two fields that do
2599 -- overlap, and we need to know if that is OK since they are in
2600 -- different variant, or whether we have a definite problem.
2602 if Overlap_Check_Required then
2603 Overlap_Check2 : declare
2604 C1_Ent, C2_Ent : Entity_Id;
2605 -- Entities of components being checked for overlap
2608 -- Component_List node whose Component_Items are being checked
2611 -- Component declaration for component being checked
2614 C1_Ent := First_Entity (Base_Type (Rectype));
2616 -- Loop through all components in record. For each component check
2617 -- for overlap with any of the preceding elements on the component
2618 -- list containing the component and also, if the component is in
2619 -- a variant, check against components outside the case structure.
2620 -- This latter test is repeated recursively up the variant tree.
2622 Main_Component_Loop : while Present (C1_Ent) loop
2623 if Ekind (C1_Ent) /= E_Component
2624 and then Ekind (C1_Ent) /= E_Discriminant
2626 goto Continue_Main_Component_Loop;
2629 -- Skip overlap check if entity has no declaration node. This
2630 -- happens with discriminants in constrained derived types.
2631 -- Probably we are missing some checks as a result, but that
2632 -- does not seem terribly serious ???
2634 if No (Declaration_Node (C1_Ent)) then
2635 goto Continue_Main_Component_Loop;
2638 Clist := Parent (List_Containing (Declaration_Node (C1_Ent)));
2640 -- Loop through component lists that need checking. Check the
2641 -- current component list and all lists in variants above us.
2643 Component_List_Loop : loop
2645 -- If derived type definition, go to full declaration
2646 -- If at outer level, check discriminants if there are any.
2648 if Nkind (Clist) = N_Derived_Type_Definition then
2649 Clist := Parent (Clist);
2652 -- Outer level of record definition, check discriminants
2654 if Nkind_In (Clist, N_Full_Type_Declaration,
2655 N_Private_Type_Declaration)
2657 if Has_Discriminants (Defining_Identifier (Clist)) then
2659 First_Discriminant (Defining_Identifier (Clist));
2661 while Present (C2_Ent) loop
2662 exit when C1_Ent = C2_Ent;
2663 Check_Component_Overlap (C1_Ent, C2_Ent);
2664 Next_Discriminant (C2_Ent);
2668 -- Record extension case
2670 elsif Nkind (Clist) = N_Derived_Type_Definition then
2673 -- Otherwise check one component list
2676 Citem := First (Component_Items (Clist));
2678 while Present (Citem) loop
2679 if Nkind (Citem) = N_Component_Declaration then
2680 C2_Ent := Defining_Identifier (Citem);
2681 exit when C1_Ent = C2_Ent;
2682 Check_Component_Overlap (C1_Ent, C2_Ent);
2689 -- Check for variants above us (the parent of the Clist can
2690 -- be a variant, in which case its parent is a variant part,
2691 -- and the parent of the variant part is a component list
2692 -- whose components must all be checked against the current
2693 -- component for overlap).
2695 if Nkind (Parent (Clist)) = N_Variant then
2696 Clist := Parent (Parent (Parent (Clist)));
2698 -- Check for possible discriminant part in record, this is
2699 -- treated essentially as another level in the recursion.
2700 -- For this case the parent of the component list is the
2701 -- record definition, and its parent is the full type
2702 -- declaration containing the discriminant specifications.
2704 elsif Nkind (Parent (Clist)) = N_Record_Definition then
2705 Clist := Parent (Parent ((Clist)));
2707 -- If neither of these two cases, we are at the top of
2711 exit Component_List_Loop;
2713 end loop Component_List_Loop;
2715 <<Continue_Main_Component_Loop>>
2716 Next_Entity (C1_Ent);
2718 end loop Main_Component_Loop;
2722 -- For records that have component clauses for all components, and whose
2723 -- size is less than or equal to 32, we need to know the size in the
2724 -- front end to activate possible packed array processing where the
2725 -- component type is a record.
2727 -- At this stage Hbit + 1 represents the first unused bit from all the
2728 -- component clauses processed, so if the component clauses are
2729 -- complete, then this is the length of the record.
2731 -- For records longer than System.Storage_Unit, and for those where not
2732 -- all components have component clauses, the back end determines the
2733 -- length (it may for example be appropriate to round up the size
2734 -- to some convenient boundary, based on alignment considerations, etc).
2736 if Unknown_RM_Size (Rectype) and then Hbit + 1 <= 32 then
2738 -- Nothing to do if at least one component has no component clause
2740 Comp := First_Component_Or_Discriminant (Rectype);
2741 while Present (Comp) loop
2742 exit when No (Component_Clause (Comp));
2743 Next_Component_Or_Discriminant (Comp);
2746 -- If we fall out of loop, all components have component clauses
2747 -- and so we can set the size to the maximum value.
2750 Set_RM_Size (Rectype, Hbit + 1);
2754 -- Check missing components if Complete_Representation pragma appeared
2756 if Present (CR_Pragma) then
2757 Comp := First_Component_Or_Discriminant (Rectype);
2758 while Present (Comp) loop
2759 if No (Component_Clause (Comp)) then
2761 ("missing component clause for &", CR_Pragma, Comp);
2764 Next_Component_Or_Discriminant (Comp);
2767 -- If no Complete_Representation pragma, warn if missing components
2769 elsif Warn_On_Unrepped_Components then
2771 Num_Repped_Components : Nat := 0;
2772 Num_Unrepped_Components : Nat := 0;
2775 -- First count number of repped and unrepped components
2777 Comp := First_Component_Or_Discriminant (Rectype);
2778 while Present (Comp) loop
2779 if Present (Component_Clause (Comp)) then
2780 Num_Repped_Components := Num_Repped_Components + 1;
2782 Num_Unrepped_Components := Num_Unrepped_Components + 1;
2785 Next_Component_Or_Discriminant (Comp);
2788 -- We are only interested in the case where there is at least one
2789 -- unrepped component, and at least half the components have rep
2790 -- clauses. We figure that if less than half have them, then the
2791 -- partial rep clause is really intentional. If the component
2792 -- type has no underlying type set at this point (as for a generic
2793 -- formal type), we don't know enough to give a warning on the
2796 if Num_Unrepped_Components > 0
2797 and then Num_Unrepped_Components < Num_Repped_Components
2799 Comp := First_Component_Or_Discriminant (Rectype);
2800 while Present (Comp) loop
2801 if No (Component_Clause (Comp))
2802 and then Comes_From_Source (Comp)
2803 and then Present (Underlying_Type (Etype (Comp)))
2804 and then (Is_Scalar_Type (Underlying_Type (Etype (Comp)))
2805 or else Size_Known_At_Compile_Time
2806 (Underlying_Type (Etype (Comp))))
2807 and then not Has_Warnings_Off (Rectype)
2809 Error_Msg_Sloc := Sloc (Comp);
2811 ("?no component clause given for & declared #",
2815 Next_Component_Or_Discriminant (Comp);
2820 end Analyze_Record_Representation_Clause;
2822 -----------------------------
2823 -- Check_Component_Overlap --
2824 -----------------------------
2826 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id) is
2828 if Present (Component_Clause (C1_Ent))
2829 and then Present (Component_Clause (C2_Ent))
2831 -- Exclude odd case where we have two tag fields in the same record,
2832 -- both at location zero. This seems a bit strange, but it seems to
2833 -- happen in some circumstances ???
2835 if Chars (C1_Ent) = Name_uTag
2836 and then Chars (C2_Ent) = Name_uTag
2841 -- Here we check if the two fields overlap
2844 S1 : constant Uint := Component_Bit_Offset (C1_Ent);
2845 S2 : constant Uint := Component_Bit_Offset (C2_Ent);
2846 E1 : constant Uint := S1 + Esize (C1_Ent);
2847 E2 : constant Uint := S2 + Esize (C2_Ent);
2850 if E2 <= S1 or else E1 <= S2 then
2854 Component_Name (Component_Clause (C2_Ent));
2855 Error_Msg_Sloc := Sloc (Error_Msg_Node_2);
2857 Component_Name (Component_Clause (C1_Ent));
2859 ("component& overlaps & #",
2860 Component_Name (Component_Clause (C1_Ent)));
2864 end Check_Component_Overlap;
2866 -----------------------------------
2867 -- Check_Constant_Address_Clause --
2868 -----------------------------------
2870 procedure Check_Constant_Address_Clause
2874 procedure Check_At_Constant_Address (Nod : Node_Id);
2875 -- Checks that the given node N represents a name whose 'Address is
2876 -- constant (in the same sense as OK_Constant_Address_Clause, i.e. the
2877 -- address value is the same at the point of declaration of U_Ent and at
2878 -- the time of elaboration of the address clause.
2880 procedure Check_Expr_Constants (Nod : Node_Id);
2881 -- Checks that Nod meets the requirements for a constant address clause
2882 -- in the sense of the enclosing procedure.
2884 procedure Check_List_Constants (Lst : List_Id);
2885 -- Check that all elements of list Lst meet the requirements for a
2886 -- constant address clause in the sense of the enclosing procedure.
2888 -------------------------------
2889 -- Check_At_Constant_Address --
2890 -------------------------------
2892 procedure Check_At_Constant_Address (Nod : Node_Id) is
2894 if Is_Entity_Name (Nod) then
2895 if Present (Address_Clause (Entity ((Nod)))) then
2897 ("invalid address clause for initialized object &!",
2900 ("address for& cannot" &
2901 " depend on another address clause! (RM 13.1(22))!",
2904 elsif In_Same_Source_Unit (Entity (Nod), U_Ent)
2905 and then Sloc (U_Ent) < Sloc (Entity (Nod))
2908 ("invalid address clause for initialized object &!",
2910 Error_Msg_Name_1 := Chars (Entity (Nod));
2911 Error_Msg_Name_2 := Chars (U_Ent);
2913 ("\% must be defined before % (RM 13.1(22))!",
2917 elsif Nkind (Nod) = N_Selected_Component then
2919 T : constant Entity_Id := Etype (Prefix (Nod));
2922 if (Is_Record_Type (T)
2923 and then Has_Discriminants (T))
2926 and then Is_Record_Type (Designated_Type (T))
2927 and then Has_Discriminants (Designated_Type (T)))
2930 ("invalid address clause for initialized object &!",
2933 ("\address cannot depend on component" &
2934 " of discriminated record (RM 13.1(22))!",
2937 Check_At_Constant_Address (Prefix (Nod));
2941 elsif Nkind (Nod) = N_Indexed_Component then
2942 Check_At_Constant_Address (Prefix (Nod));
2943 Check_List_Constants (Expressions (Nod));
2946 Check_Expr_Constants (Nod);
2948 end Check_At_Constant_Address;
2950 --------------------------
2951 -- Check_Expr_Constants --
2952 --------------------------
2954 procedure Check_Expr_Constants (Nod : Node_Id) is
2955 Loc_U_Ent : constant Source_Ptr := Sloc (U_Ent);
2956 Ent : Entity_Id := Empty;
2959 if Nkind (Nod) in N_Has_Etype
2960 and then Etype (Nod) = Any_Type
2966 when N_Empty | N_Error =>
2969 when N_Identifier | N_Expanded_Name =>
2970 Ent := Entity (Nod);
2972 -- We need to look at the original node if it is different
2973 -- from the node, since we may have rewritten things and
2974 -- substituted an identifier representing the rewrite.
2976 if Original_Node (Nod) /= Nod then
2977 Check_Expr_Constants (Original_Node (Nod));
2979 -- If the node is an object declaration without initial
2980 -- value, some code has been expanded, and the expression
2981 -- is not constant, even if the constituents might be
2982 -- acceptable, as in A'Address + offset.
2984 if Ekind (Ent) = E_Variable
2986 Nkind (Declaration_Node (Ent)) = N_Object_Declaration
2988 No (Expression (Declaration_Node (Ent)))
2991 ("invalid address clause for initialized object &!",
2994 -- If entity is constant, it may be the result of expanding
2995 -- a check. We must verify that its declaration appears
2996 -- before the object in question, else we also reject the
2999 elsif Ekind (Ent) = E_Constant
3000 and then In_Same_Source_Unit (Ent, U_Ent)
3001 and then Sloc (Ent) > Loc_U_Ent
3004 ("invalid address clause for initialized object &!",
3011 -- Otherwise look at the identifier and see if it is OK
3013 if Ekind (Ent) = E_Named_Integer
3015 Ekind (Ent) = E_Named_Real
3022 Ekind (Ent) = E_Constant
3024 Ekind (Ent) = E_In_Parameter
3026 -- This is the case where we must have Ent defined before
3027 -- U_Ent. Clearly if they are in different units this
3028 -- requirement is met since the unit containing Ent is
3029 -- already processed.
3031 if not In_Same_Source_Unit (Ent, U_Ent) then
3034 -- Otherwise location of Ent must be before the location
3035 -- of U_Ent, that's what prior defined means.
3037 elsif Sloc (Ent) < Loc_U_Ent then
3042 ("invalid address clause for initialized object &!",
3044 Error_Msg_Name_1 := Chars (Ent);
3045 Error_Msg_Name_2 := Chars (U_Ent);
3047 ("\% must be defined before % (RM 13.1(22))!",
3051 elsif Nkind (Original_Node (Nod)) = N_Function_Call then
3052 Check_Expr_Constants (Original_Node (Nod));
3056 ("invalid address clause for initialized object &!",
3059 if Comes_From_Source (Ent) then
3060 Error_Msg_Name_1 := Chars (Ent);
3062 ("\reference to variable% not allowed"
3063 & " (RM 13.1(22))!", Nod);
3066 ("non-static expression not allowed"
3067 & " (RM 13.1(22))!", Nod);
3071 when N_Integer_Literal =>
3073 -- If this is a rewritten unchecked conversion, in a system
3074 -- where Address is an integer type, always use the base type
3075 -- for a literal value. This is user-friendly and prevents
3076 -- order-of-elaboration issues with instances of unchecked
3079 if Nkind (Original_Node (Nod)) = N_Function_Call then
3080 Set_Etype (Nod, Base_Type (Etype (Nod)));
3083 when N_Real_Literal |
3085 N_Character_Literal =>
3089 Check_Expr_Constants (Low_Bound (Nod));
3090 Check_Expr_Constants (High_Bound (Nod));
3092 when N_Explicit_Dereference =>
3093 Check_Expr_Constants (Prefix (Nod));
3095 when N_Indexed_Component =>
3096 Check_Expr_Constants (Prefix (Nod));
3097 Check_List_Constants (Expressions (Nod));
3100 Check_Expr_Constants (Prefix (Nod));
3101 Check_Expr_Constants (Discrete_Range (Nod));
3103 when N_Selected_Component =>
3104 Check_Expr_Constants (Prefix (Nod));
3106 when N_Attribute_Reference =>
3107 if Attribute_Name (Nod) = Name_Address
3109 Attribute_Name (Nod) = Name_Access
3111 Attribute_Name (Nod) = Name_Unchecked_Access
3113 Attribute_Name (Nod) = Name_Unrestricted_Access
3115 Check_At_Constant_Address (Prefix (Nod));
3118 Check_Expr_Constants (Prefix (Nod));
3119 Check_List_Constants (Expressions (Nod));
3123 Check_List_Constants (Component_Associations (Nod));
3124 Check_List_Constants (Expressions (Nod));
3126 when N_Component_Association =>
3127 Check_Expr_Constants (Expression (Nod));
3129 when N_Extension_Aggregate =>
3130 Check_Expr_Constants (Ancestor_Part (Nod));
3131 Check_List_Constants (Component_Associations (Nod));
3132 Check_List_Constants (Expressions (Nod));
3137 when N_Binary_Op | N_And_Then | N_Or_Else | N_Membership_Test =>
3138 Check_Expr_Constants (Left_Opnd (Nod));
3139 Check_Expr_Constants (Right_Opnd (Nod));
3142 Check_Expr_Constants (Right_Opnd (Nod));
3144 when N_Type_Conversion |
3145 N_Qualified_Expression |
3147 Check_Expr_Constants (Expression (Nod));
3149 when N_Unchecked_Type_Conversion =>
3150 Check_Expr_Constants (Expression (Nod));
3152 -- If this is a rewritten unchecked conversion, subtypes in
3153 -- this node are those created within the instance. To avoid
3154 -- order of elaboration issues, replace them with their base
3155 -- types. Note that address clauses can cause order of
3156 -- elaboration problems because they are elaborated by the
3157 -- back-end at the point of definition, and may mention
3158 -- entities declared in between (as long as everything is
3159 -- static). It is user-friendly to allow unchecked conversions
3162 if Nkind (Original_Node (Nod)) = N_Function_Call then
3163 Set_Etype (Expression (Nod),
3164 Base_Type (Etype (Expression (Nod))));
3165 Set_Etype (Nod, Base_Type (Etype (Nod)));
3168 when N_Function_Call =>
3169 if not Is_Pure (Entity (Name (Nod))) then
3171 ("invalid address clause for initialized object &!",
3175 ("\function & is not pure (RM 13.1(22))!",
3176 Nod, Entity (Name (Nod)));
3179 Check_List_Constants (Parameter_Associations (Nod));
3182 when N_Parameter_Association =>
3183 Check_Expr_Constants (Explicit_Actual_Parameter (Nod));
3187 ("invalid address clause for initialized object &!",
3190 ("\must be constant defined before& (RM 13.1(22))!",
3193 end Check_Expr_Constants;
3195 --------------------------
3196 -- Check_List_Constants --
3197 --------------------------
3199 procedure Check_List_Constants (Lst : List_Id) is
3203 if Present (Lst) then
3204 Nod1 := First (Lst);
3205 while Present (Nod1) loop
3206 Check_Expr_Constants (Nod1);
3210 end Check_List_Constants;
3212 -- Start of processing for Check_Constant_Address_Clause
3215 Check_Expr_Constants (Expr);
3216 end Check_Constant_Address_Clause;
3222 procedure Check_Size
3226 Biased : out Boolean)
3228 UT : constant Entity_Id := Underlying_Type (T);
3234 -- Dismiss cases for generic types or types with previous errors
3237 or else UT = Any_Type
3238 or else Is_Generic_Type (UT)
3239 or else Is_Generic_Type (Root_Type (UT))
3243 -- Check case of bit packed array
3245 elsif Is_Array_Type (UT)
3246 and then Known_Static_Component_Size (UT)
3247 and then Is_Bit_Packed_Array (UT)
3255 Asiz := Component_Size (UT);
3256 Indx := First_Index (UT);
3258 Ityp := Etype (Indx);
3260 -- If non-static bound, then we are not in the business of
3261 -- trying to check the length, and indeed an error will be
3262 -- issued elsewhere, since sizes of non-static array types
3263 -- cannot be set implicitly or explicitly.
3265 if not Is_Static_Subtype (Ityp) then
3269 -- Otherwise accumulate next dimension
3271 Asiz := Asiz * (Expr_Value (Type_High_Bound (Ityp)) -
3272 Expr_Value (Type_Low_Bound (Ityp)) +
3276 exit when No (Indx);
3282 Error_Msg_Uint_1 := Asiz;
3284 ("size for& too small, minimum allowed is ^", N, T);
3285 Set_Esize (T, Asiz);
3286 Set_RM_Size (T, Asiz);
3290 -- All other composite types are ignored
3292 elsif Is_Composite_Type (UT) then
3295 -- For fixed-point types, don't check minimum if type is not frozen,
3296 -- since we don't know all the characteristics of the type that can
3297 -- affect the size (e.g. a specified small) till freeze time.
3299 elsif Is_Fixed_Point_Type (UT)
3300 and then not Is_Frozen (UT)
3304 -- Cases for which a minimum check is required
3307 -- Ignore if specified size is correct for the type
3309 if Known_Esize (UT) and then Siz = Esize (UT) then
3313 -- Otherwise get minimum size
3315 M := UI_From_Int (Minimum_Size (UT));
3319 -- Size is less than minimum size, but one possibility remains
3320 -- that we can manage with the new size if we bias the type.
3322 M := UI_From_Int (Minimum_Size (UT, Biased => True));
3325 Error_Msg_Uint_1 := M;
3327 ("size for& too small, minimum allowed is ^", N, T);
3337 -------------------------
3338 -- Get_Alignment_Value --
3339 -------------------------
3341 function Get_Alignment_Value (Expr : Node_Id) return Uint is
3342 Align : constant Uint := Static_Integer (Expr);
3345 if Align = No_Uint then
3348 elsif Align <= 0 then
3349 Error_Msg_N ("alignment value must be positive", Expr);
3353 for J in Int range 0 .. 64 loop
3355 M : constant Uint := Uint_2 ** J;
3358 exit when M = Align;
3362 ("alignment value must be power of 2", Expr);
3370 end Get_Alignment_Value;
3376 procedure Initialize is
3378 Unchecked_Conversions.Init;
3381 -------------------------
3382 -- Is_Operational_Item --
3383 -------------------------
3385 function Is_Operational_Item (N : Node_Id) return Boolean is
3387 if Nkind (N) /= N_Attribute_Definition_Clause then
3391 Id : constant Attribute_Id := Get_Attribute_Id (Chars (N));
3393 return Id = Attribute_Input
3394 or else Id = Attribute_Output
3395 or else Id = Attribute_Read
3396 or else Id = Attribute_Write
3397 or else Id = Attribute_External_Tag;
3400 end Is_Operational_Item;
3406 function Minimum_Size
3408 Biased : Boolean := False) return Nat
3410 Lo : Uint := No_Uint;
3411 Hi : Uint := No_Uint;
3412 LoR : Ureal := No_Ureal;
3413 HiR : Ureal := No_Ureal;
3414 LoSet : Boolean := False;
3415 HiSet : Boolean := False;
3419 R_Typ : constant Entity_Id := Root_Type (T);
3422 -- If bad type, return 0
3424 if T = Any_Type then
3427 -- For generic types, just return zero. There cannot be any legitimate
3428 -- need to know such a size, but this routine may be called with a
3429 -- generic type as part of normal processing.
3431 elsif Is_Generic_Type (R_Typ)
3432 or else R_Typ = Any_Type
3436 -- Access types. Normally an access type cannot have a size smaller
3437 -- than the size of System.Address. The exception is on VMS, where
3438 -- we have short and long addresses, and it is possible for an access
3439 -- type to have a short address size (and thus be less than the size
3440 -- of System.Address itself). We simply skip the check for VMS, and
3441 -- leave it to the back end to do the check.
3443 elsif Is_Access_Type (T) then
3444 if OpenVMS_On_Target then
3447 return System_Address_Size;
3450 -- Floating-point types
3452 elsif Is_Floating_Point_Type (T) then
3453 return UI_To_Int (Esize (R_Typ));
3457 elsif Is_Discrete_Type (T) then
3459 -- The following loop is looking for the nearest compile time known
3460 -- bounds following the ancestor subtype chain. The idea is to find
3461 -- the most restrictive known bounds information.
3465 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3470 if Compile_Time_Known_Value (Type_Low_Bound (Ancest)) then
3471 Lo := Expr_Rep_Value (Type_Low_Bound (Ancest));
3478 if Compile_Time_Known_Value (Type_High_Bound (Ancest)) then
3479 Hi := Expr_Rep_Value (Type_High_Bound (Ancest));
3485 Ancest := Ancestor_Subtype (Ancest);
3488 Ancest := Base_Type (T);
3490 if Is_Generic_Type (Ancest) then
3496 -- Fixed-point types. We can't simply use Expr_Value to get the
3497 -- Corresponding_Integer_Value values of the bounds, since these do not
3498 -- get set till the type is frozen, and this routine can be called
3499 -- before the type is frozen. Similarly the test for bounds being static
3500 -- needs to include the case where we have unanalyzed real literals for
3503 elsif Is_Fixed_Point_Type (T) then
3505 -- The following loop is looking for the nearest compile time known
3506 -- bounds following the ancestor subtype chain. The idea is to find
3507 -- the most restrictive known bounds information.
3511 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3515 -- Note: In the following two tests for LoSet and HiSet, it may
3516 -- seem redundant to test for N_Real_Literal here since normally
3517 -- one would assume that the test for the value being known at
3518 -- compile time includes this case. However, there is a glitch.
3519 -- If the real literal comes from folding a non-static expression,
3520 -- then we don't consider any non- static expression to be known
3521 -- at compile time if we are in configurable run time mode (needed
3522 -- in some cases to give a clearer definition of what is and what
3523 -- is not accepted). So the test is indeed needed. Without it, we
3524 -- would set neither Lo_Set nor Hi_Set and get an infinite loop.
3527 if Nkind (Type_Low_Bound (Ancest)) = N_Real_Literal
3528 or else Compile_Time_Known_Value (Type_Low_Bound (Ancest))
3530 LoR := Expr_Value_R (Type_Low_Bound (Ancest));
3537 if Nkind (Type_High_Bound (Ancest)) = N_Real_Literal
3538 or else Compile_Time_Known_Value (Type_High_Bound (Ancest))
3540 HiR := Expr_Value_R (Type_High_Bound (Ancest));
3546 Ancest := Ancestor_Subtype (Ancest);
3549 Ancest := Base_Type (T);
3551 if Is_Generic_Type (Ancest) then
3557 Lo := UR_To_Uint (LoR / Small_Value (T));
3558 Hi := UR_To_Uint (HiR / Small_Value (T));
3560 -- No other types allowed
3563 raise Program_Error;
3566 -- Fall through with Hi and Lo set. Deal with biased case
3568 if (Biased and then not Is_Fixed_Point_Type (T))
3569 or else Has_Biased_Representation (T)
3575 -- Signed case. Note that we consider types like range 1 .. -1 to be
3576 -- signed for the purpose of computing the size, since the bounds have
3577 -- to be accommodated in the base type.
3579 if Lo < 0 or else Hi < 0 then
3583 -- S = size, B = 2 ** (size - 1) (can accommodate -B .. +(B - 1))
3584 -- Note that we accommodate the case where the bounds cross. This
3585 -- can happen either because of the way the bounds are declared
3586 -- or because of the algorithm in Freeze_Fixed_Point_Type.
3600 -- If both bounds are positive, make sure that both are represen-
3601 -- table in the case where the bounds are crossed. This can happen
3602 -- either because of the way the bounds are declared, or because of
3603 -- the algorithm in Freeze_Fixed_Point_Type.
3609 -- S = size, (can accommodate 0 .. (2**size - 1))
3612 while Hi >= Uint_2 ** S loop
3620 ---------------------------
3621 -- New_Stream_Subprogram --
3622 ---------------------------
3624 procedure New_Stream_Subprogram
3628 Nam : TSS_Name_Type)
3630 Loc : constant Source_Ptr := Sloc (N);
3631 Sname : constant Name_Id := Make_TSS_Name (Base_Type (Ent), Nam);
3632 Subp_Id : Entity_Id;
3633 Subp_Decl : Node_Id;
3637 Defer_Declaration : constant Boolean :=
3638 Is_Tagged_Type (Ent) or else Is_Private_Type (Ent);
3639 -- For a tagged type, there is a declaration for each stream attribute
3640 -- at the freeze point, and we must generate only a completion of this
3641 -- declaration. We do the same for private types, because the full view
3642 -- might be tagged. Otherwise we generate a declaration at the point of
3643 -- the attribute definition clause.
3645 function Build_Spec return Node_Id;
3646 -- Used for declaration and renaming declaration, so that this is
3647 -- treated as a renaming_as_body.
3653 function Build_Spec return Node_Id is
3654 Out_P : constant Boolean := (Nam = TSS_Stream_Read);
3657 T_Ref : constant Node_Id := New_Reference_To (Etyp, Loc);
3660 Subp_Id := Make_Defining_Identifier (Loc, Sname);
3662 -- S : access Root_Stream_Type'Class
3664 Formals := New_List (
3665 Make_Parameter_Specification (Loc,
3666 Defining_Identifier =>
3667 Make_Defining_Identifier (Loc, Name_S),
3669 Make_Access_Definition (Loc,
3672 Designated_Type (Etype (F)), Loc))));
3674 if Nam = TSS_Stream_Input then
3675 Spec := Make_Function_Specification (Loc,
3676 Defining_Unit_Name => Subp_Id,
3677 Parameter_Specifications => Formals,
3678 Result_Definition => T_Ref);
3683 Make_Parameter_Specification (Loc,
3684 Defining_Identifier => Make_Defining_Identifier (Loc, Name_V),
3685 Out_Present => Out_P,
3686 Parameter_Type => T_Ref));
3688 Spec := Make_Procedure_Specification (Loc,
3689 Defining_Unit_Name => Subp_Id,
3690 Parameter_Specifications => Formals);
3696 -- Start of processing for New_Stream_Subprogram
3699 F := First_Formal (Subp);
3701 if Ekind (Subp) = E_Procedure then
3702 Etyp := Etype (Next_Formal (F));
3704 Etyp := Etype (Subp);
3707 -- Prepare subprogram declaration and insert it as an action on the
3708 -- clause node. The visibility for this entity is used to test for
3709 -- visibility of the attribute definition clause (in the sense of
3710 -- 8.3(23) as amended by AI-195).
3712 if not Defer_Declaration then
3714 Make_Subprogram_Declaration (Loc,
3715 Specification => Build_Spec);
3717 -- For a tagged type, there is always a visible declaration for each
3718 -- stream TSS (it is a predefined primitive operation), and the
3719 -- completion of this declaration occurs at the freeze point, which is
3720 -- not always visible at places where the attribute definition clause is
3721 -- visible. So, we create a dummy entity here for the purpose of
3722 -- tracking the visibility of the attribute definition clause itself.
3726 Make_Defining_Identifier (Loc,
3727 Chars => New_External_Name (Sname, 'V'));
3729 Make_Object_Declaration (Loc,
3730 Defining_Identifier => Subp_Id,
3731 Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc));
3734 Insert_Action (N, Subp_Decl);
3735 Set_Entity (N, Subp_Id);
3738 Make_Subprogram_Renaming_Declaration (Loc,
3739 Specification => Build_Spec,
3740 Name => New_Reference_To (Subp, Loc));
3742 if Defer_Declaration then
3743 Set_TSS (Base_Type (Ent), Subp_Id);
3745 Insert_Action (N, Subp_Decl);
3746 Copy_TSS (Subp_Id, Base_Type (Ent));
3748 end New_Stream_Subprogram;
3750 ------------------------
3751 -- Rep_Item_Too_Early --
3752 ------------------------
3754 function Rep_Item_Too_Early (T : Entity_Id; N : Node_Id) return Boolean is
3756 -- Cannot apply non-operational rep items to generic types
3758 if Is_Operational_Item (N) then
3762 and then Is_Generic_Type (Root_Type (T))
3765 ("representation item not allowed for generic type", N);
3769 -- Otherwise check for incomplete type
3771 if Is_Incomplete_Or_Private_Type (T)
3772 and then No (Underlying_Type (T))
3775 ("representation item must be after full type declaration", N);
3778 -- If the type has incomplete components, a representation clause is
3779 -- illegal but stream attributes and Convention pragmas are correct.
3781 elsif Has_Private_Component (T) then
3782 if Nkind (N) = N_Pragma then
3786 ("representation item must appear after type is fully defined",
3793 end Rep_Item_Too_Early;
3795 -----------------------
3796 -- Rep_Item_Too_Late --
3797 -----------------------
3799 function Rep_Item_Too_Late
3802 FOnly : Boolean := False) return Boolean
3805 Parent_Type : Entity_Id;
3808 -- Output the too late message. Note that this is not considered a
3809 -- serious error, since the effect is simply that we ignore the
3810 -- representation clause in this case.
3816 procedure Too_Late is
3818 Error_Msg_N ("|representation item appears too late!", N);
3821 -- Start of processing for Rep_Item_Too_Late
3824 -- First make sure entity is not frozen (RM 13.1(9)). Exclude imported
3825 -- types, which may be frozen if they appear in a representation clause
3826 -- for a local type.
3829 and then not From_With_Type (T)
3832 S := First_Subtype (T);
3834 if Present (Freeze_Node (S)) then
3836 ("?no more representation items for }", Freeze_Node (S), S);
3841 -- Check for case of non-tagged derived type whose parent either has
3842 -- primitive operations, or is a by reference type (RM 13.1(10)).
3846 and then Is_Derived_Type (T)
3847 and then not Is_Tagged_Type (T)
3849 Parent_Type := Etype (Base_Type (T));
3851 if Has_Primitive_Operations (Parent_Type) then
3854 ("primitive operations already defined for&!", N, Parent_Type);
3857 elsif Is_By_Reference_Type (Parent_Type) then
3860 ("parent type & is a by reference type!", N, Parent_Type);
3865 -- No error, link item into head of chain of rep items for the entity,
3866 -- but avoid chaining if we have an overloadable entity, and the pragma
3867 -- is one that can apply to multiple overloaded entities.
3869 if Is_Overloadable (T)
3870 and then Nkind (N) = N_Pragma
3873 Pname : constant Name_Id := Pragma_Name (N);
3875 if Pname = Name_Convention or else
3876 Pname = Name_Import or else
3877 Pname = Name_Export or else
3878 Pname = Name_External or else
3879 Pname = Name_Interface
3886 Record_Rep_Item (T, N);
3888 end Rep_Item_Too_Late;
3890 -------------------------
3891 -- Same_Representation --
3892 -------------------------
3894 function Same_Representation (Typ1, Typ2 : Entity_Id) return Boolean is
3895 T1 : constant Entity_Id := Underlying_Type (Typ1);
3896 T2 : constant Entity_Id := Underlying_Type (Typ2);
3899 -- A quick check, if base types are the same, then we definitely have
3900 -- the same representation, because the subtype specific representation
3901 -- attributes (Size and Alignment) do not affect representation from
3902 -- the point of view of this test.
3904 if Base_Type (T1) = Base_Type (T2) then
3907 elsif Is_Private_Type (Base_Type (T2))
3908 and then Base_Type (T1) = Full_View (Base_Type (T2))
3913 -- Tagged types never have differing representations
3915 if Is_Tagged_Type (T1) then
3919 -- Representations are definitely different if conventions differ
3921 if Convention (T1) /= Convention (T2) then
3925 -- Representations are different if component alignments differ
3927 if (Is_Record_Type (T1) or else Is_Array_Type (T1))
3929 (Is_Record_Type (T2) or else Is_Array_Type (T2))
3930 and then Component_Alignment (T1) /= Component_Alignment (T2)
3935 -- For arrays, the only real issue is component size. If we know the
3936 -- component size for both arrays, and it is the same, then that's
3937 -- good enough to know we don't have a change of representation.
3939 if Is_Array_Type (T1) then
3940 if Known_Component_Size (T1)
3941 and then Known_Component_Size (T2)
3942 and then Component_Size (T1) = Component_Size (T2)
3948 -- Types definitely have same representation if neither has non-standard
3949 -- representation since default representations are always consistent.
3950 -- If only one has non-standard representation, and the other does not,
3951 -- then we consider that they do not have the same representation. They
3952 -- might, but there is no way of telling early enough.
3954 if Has_Non_Standard_Rep (T1) then
3955 if not Has_Non_Standard_Rep (T2) then
3959 return not Has_Non_Standard_Rep (T2);
3962 -- Here the two types both have non-standard representation, and we need
3963 -- to determine if they have the same non-standard representation.
3965 -- For arrays, we simply need to test if the component sizes are the
3966 -- same. Pragma Pack is reflected in modified component sizes, so this
3967 -- check also deals with pragma Pack.
3969 if Is_Array_Type (T1) then
3970 return Component_Size (T1) = Component_Size (T2);
3972 -- Tagged types always have the same representation, because it is not
3973 -- possible to specify different representations for common fields.
3975 elsif Is_Tagged_Type (T1) then
3978 -- Case of record types
3980 elsif Is_Record_Type (T1) then
3982 -- Packed status must conform
3984 if Is_Packed (T1) /= Is_Packed (T2) then
3987 -- Otherwise we must check components. Typ2 maybe a constrained
3988 -- subtype with fewer components, so we compare the components
3989 -- of the base types.
3992 Record_Case : declare
3993 CD1, CD2 : Entity_Id;
3995 function Same_Rep return Boolean;
3996 -- CD1 and CD2 are either components or discriminants. This
3997 -- function tests whether the two have the same representation
4003 function Same_Rep return Boolean is
4005 if No (Component_Clause (CD1)) then
4006 return No (Component_Clause (CD2));
4010 Present (Component_Clause (CD2))
4012 Component_Bit_Offset (CD1) = Component_Bit_Offset (CD2)
4014 Esize (CD1) = Esize (CD2);
4018 -- Start processing for Record_Case
4021 if Has_Discriminants (T1) then
4022 CD1 := First_Discriminant (T1);
4023 CD2 := First_Discriminant (T2);
4025 -- The number of discriminants may be different if the
4026 -- derived type has fewer (constrained by values). The
4027 -- invisible discriminants retain the representation of
4028 -- the original, so the discrepancy does not per se
4029 -- indicate a different representation.
4032 and then Present (CD2)
4034 if not Same_Rep then
4037 Next_Discriminant (CD1);
4038 Next_Discriminant (CD2);
4043 CD1 := First_Component (Underlying_Type (Base_Type (T1)));
4044 CD2 := First_Component (Underlying_Type (Base_Type (T2)));
4046 while Present (CD1) loop
4047 if not Same_Rep then
4050 Next_Component (CD1);
4051 Next_Component (CD2);
4059 -- For enumeration types, we must check each literal to see if the
4060 -- representation is the same. Note that we do not permit enumeration
4061 -- representation clauses for Character and Wide_Character, so these
4062 -- cases were already dealt with.
4064 elsif Is_Enumeration_Type (T1) then
4066 Enumeration_Case : declare
4070 L1 := First_Literal (T1);
4071 L2 := First_Literal (T2);
4073 while Present (L1) loop
4074 if Enumeration_Rep (L1) /= Enumeration_Rep (L2) then
4084 end Enumeration_Case;
4086 -- Any other types have the same representation for these purposes
4091 end Same_Representation;
4093 --------------------
4094 -- Set_Enum_Esize --
4095 --------------------
4097 procedure Set_Enum_Esize (T : Entity_Id) is
4105 -- Find the minimum standard size (8,16,32,64) that fits
4107 Lo := Enumeration_Rep (Entity (Type_Low_Bound (T)));
4108 Hi := Enumeration_Rep (Entity (Type_High_Bound (T)));
4111 if Lo >= -Uint_2**07 and then Hi < Uint_2**07 then
4112 Sz := Standard_Character_Size; -- May be > 8 on some targets
4114 elsif Lo >= -Uint_2**15 and then Hi < Uint_2**15 then
4117 elsif Lo >= -Uint_2**31 and then Hi < Uint_2**31 then
4120 else pragma Assert (Lo >= -Uint_2**63 and then Hi < Uint_2**63);
4125 if Hi < Uint_2**08 then
4126 Sz := Standard_Character_Size; -- May be > 8 on some targets
4128 elsif Hi < Uint_2**16 then
4131 elsif Hi < Uint_2**32 then
4134 else pragma Assert (Hi < Uint_2**63);
4139 -- That minimum is the proper size unless we have a foreign convention
4140 -- and the size required is 32 or less, in which case we bump the size
4141 -- up to 32. This is required for C and C++ and seems reasonable for
4142 -- all other foreign conventions.
4144 if Has_Foreign_Convention (T)
4145 and then Esize (T) < Standard_Integer_Size
4147 Init_Esize (T, Standard_Integer_Size);
4153 ------------------------------
4154 -- Validate_Address_Clauses --
4155 ------------------------------
4157 procedure Validate_Address_Clauses is
4159 for J in Address_Clause_Checks.First .. Address_Clause_Checks.Last loop
4161 ACCR : Address_Clause_Check_Record
4162 renames Address_Clause_Checks.Table (J);
4171 -- Skip processing of this entry if warning already posted
4173 if not Address_Warning_Posted (ACCR.N) then
4175 -- Get alignments. Really we should always have the alignment
4176 -- of the objects properly back annotated, but right now the
4177 -- back end fails to back annotate for address clauses???
4179 if Known_Alignment (ACCR.X) then
4180 X_Alignment := Alignment (ACCR.X);
4182 X_Alignment := Alignment (Etype (ACCR.X));
4185 if Known_Alignment (ACCR.Y) then
4186 Y_Alignment := Alignment (ACCR.Y);
4188 Y_Alignment := Alignment (Etype (ACCR.Y));
4191 -- Similarly obtain sizes
4193 if Known_Esize (ACCR.X) then
4194 X_Size := Esize (ACCR.X);
4196 X_Size := Esize (Etype (ACCR.X));
4199 if Known_Esize (ACCR.Y) then
4200 Y_Size := Esize (ACCR.Y);
4202 Y_Size := Esize (Etype (ACCR.Y));
4205 -- Check for large object overlaying smaller one
4208 and then X_Size > Uint_0
4209 and then X_Size > Y_Size
4212 ("?size for overlaid object is too small", ACCR.N);
4213 Error_Msg_Uint_1 := X_Size;
4215 ("\?size of & is ^", ACCR.N, ACCR.X);
4216 Error_Msg_Uint_1 := Y_Size;
4218 ("\?size of & is ^", ACCR.N, ACCR.Y);
4220 -- Check for inadequate alignment. Again the defensive check
4221 -- on Y_Alignment should not be needed, but because of the
4222 -- failure in back end annotation, we can have an alignment
4225 -- Note: we do not check alignments if we gave a size
4226 -- warning, since it would likely be redundant.
4228 elsif Y_Alignment /= Uint_0
4229 and then Y_Alignment < X_Alignment
4232 ("?specified address for& may be inconsistent "
4236 ("\?program execution may be erroneous (RM 13.3(27))",
4238 Error_Msg_Uint_1 := X_Alignment;
4240 ("\?alignment of & is ^",
4242 Error_Msg_Uint_1 := Y_Alignment;
4244 ("\?alignment of & is ^",
4250 end Validate_Address_Clauses;
4252 -----------------------------------
4253 -- Validate_Unchecked_Conversion --
4254 -----------------------------------
4256 procedure Validate_Unchecked_Conversion
4258 Act_Unit : Entity_Id)
4265 -- Obtain source and target types. Note that we call Ancestor_Subtype
4266 -- here because the processing for generic instantiation always makes
4267 -- subtypes, and we want the original frozen actual types.
4269 -- If we are dealing with private types, then do the check on their
4270 -- fully declared counterparts if the full declarations have been
4271 -- encountered (they don't have to be visible, but they must exist!)
4273 Source := Ancestor_Subtype (Etype (First_Formal (Act_Unit)));
4275 if Is_Private_Type (Source)
4276 and then Present (Underlying_Type (Source))
4278 Source := Underlying_Type (Source);
4281 Target := Ancestor_Subtype (Etype (Act_Unit));
4283 -- If either type is generic, the instantiation happens within a generic
4284 -- unit, and there is nothing to check. The proper check
4285 -- will happen when the enclosing generic is instantiated.
4287 if Is_Generic_Type (Source) or else Is_Generic_Type (Target) then
4291 if Is_Private_Type (Target)
4292 and then Present (Underlying_Type (Target))
4294 Target := Underlying_Type (Target);
4297 -- Source may be unconstrained array, but not target
4299 if Is_Array_Type (Target)
4300 and then not Is_Constrained (Target)
4303 ("unchecked conversion to unconstrained array not allowed", N);
4307 -- Warn if conversion between two different convention pointers
4309 if Is_Access_Type (Target)
4310 and then Is_Access_Type (Source)
4311 and then Convention (Target) /= Convention (Source)
4312 and then Warn_On_Unchecked_Conversion
4314 -- Give warnings for subprogram pointers only on most targets. The
4315 -- exception is VMS, where data pointers can have different lengths
4316 -- depending on the pointer convention.
4318 if Is_Access_Subprogram_Type (Target)
4319 or else Is_Access_Subprogram_Type (Source)
4320 or else OpenVMS_On_Target
4323 ("?conversion between pointers with different conventions!", N);
4327 -- Warn if one of the operands is Ada.Calendar.Time. Do not emit a
4328 -- warning when compiling GNAT-related sources.
4330 if Warn_On_Unchecked_Conversion
4331 and then not In_Predefined_Unit (N)
4332 and then RTU_Loaded (Ada_Calendar)
4334 (Chars (Source) = Name_Time
4336 Chars (Target) = Name_Time)
4338 -- If Ada.Calendar is loaded and the name of one of the operands is
4339 -- Time, there is a good chance that this is Ada.Calendar.Time.
4342 Calendar_Time : constant Entity_Id :=
4343 Full_View (RTE (RO_CA_Time));
4345 pragma Assert (Present (Calendar_Time));
4347 if Source = Calendar_Time
4348 or else Target = Calendar_Time
4351 ("?representation of 'Time values may change between " &
4352 "'G'N'A'T versions", N);
4357 -- Make entry in unchecked conversion table for later processing by
4358 -- Validate_Unchecked_Conversions, which will check sizes and alignments
4359 -- (using values set by the back-end where possible). This is only done
4360 -- if the appropriate warning is active.
4362 if Warn_On_Unchecked_Conversion then
4363 Unchecked_Conversions.Append
4364 (New_Val => UC_Entry'
4369 -- If both sizes are known statically now, then back end annotation
4370 -- is not required to do a proper check but if either size is not
4371 -- known statically, then we need the annotation.
4373 if Known_Static_RM_Size (Source)
4374 and then Known_Static_RM_Size (Target)
4378 Back_Annotate_Rep_Info := True;
4382 -- If unchecked conversion to access type, and access type is declared
4383 -- in the same unit as the unchecked conversion, then set the
4384 -- No_Strict_Aliasing flag (no strict aliasing is implicit in this
4387 if Is_Access_Type (Target) and then
4388 In_Same_Source_Unit (Target, N)
4390 Set_No_Strict_Aliasing (Implementation_Base_Type (Target));
4393 -- Generate N_Validate_Unchecked_Conversion node for back end in
4394 -- case the back end needs to perform special validation checks.
4396 -- Shouldn't this be in Exp_Ch13, since the check only gets done
4397 -- if we have full expansion and the back end is called ???
4400 Make_Validate_Unchecked_Conversion (Sloc (N));
4401 Set_Source_Type (Vnode, Source);
4402 Set_Target_Type (Vnode, Target);
4404 -- If the unchecked conversion node is in a list, just insert before it.
4405 -- If not we have some strange case, not worth bothering about.
4407 if Is_List_Member (N) then
4408 Insert_After (N, Vnode);
4410 end Validate_Unchecked_Conversion;
4412 ------------------------------------
4413 -- Validate_Unchecked_Conversions --
4414 ------------------------------------
4416 procedure Validate_Unchecked_Conversions is
4418 for N in Unchecked_Conversions.First .. Unchecked_Conversions.Last loop
4420 T : UC_Entry renames Unchecked_Conversions.Table (N);
4422 Enode : constant Node_Id := T.Enode;
4423 Source : constant Entity_Id := T.Source;
4424 Target : constant Entity_Id := T.Target;
4430 -- This validation check, which warns if we have unequal sizes for
4431 -- unchecked conversion, and thus potentially implementation
4432 -- dependent semantics, is one of the few occasions on which we
4433 -- use the official RM size instead of Esize. See description in
4434 -- Einfo "Handling of Type'Size Values" for details.
4436 if Serious_Errors_Detected = 0
4437 and then Known_Static_RM_Size (Source)
4438 and then Known_Static_RM_Size (Target)
4440 Source_Siz := RM_Size (Source);
4441 Target_Siz := RM_Size (Target);
4443 if Source_Siz /= Target_Siz then
4445 ("?types for unchecked conversion have different sizes!",
4448 if All_Errors_Mode then
4449 Error_Msg_Name_1 := Chars (Source);
4450 Error_Msg_Uint_1 := Source_Siz;
4451 Error_Msg_Name_2 := Chars (Target);
4452 Error_Msg_Uint_2 := Target_Siz;
4454 ("\size of % is ^, size of % is ^?", Enode);
4456 Error_Msg_Uint_1 := UI_Abs (Source_Siz - Target_Siz);
4458 if Is_Discrete_Type (Source)
4459 and then Is_Discrete_Type (Target)
4461 if Source_Siz > Target_Siz then
4463 ("\?^ high order bits of source will be ignored!",
4466 elsif Is_Unsigned_Type (Source) then
4468 ("\?source will be extended with ^ high order " &
4469 "zero bits?!", Enode);
4473 ("\?source will be extended with ^ high order " &
4478 elsif Source_Siz < Target_Siz then
4479 if Is_Discrete_Type (Target) then
4480 if Bytes_Big_Endian then
4482 ("\?target value will include ^ undefined " &
4487 ("\?target value will include ^ undefined " &
4494 ("\?^ trailing bits of target value will be " &
4495 "undefined!", Enode);
4498 else pragma Assert (Source_Siz > Target_Siz);
4500 ("\?^ trailing bits of source will be ignored!",
4507 -- If both types are access types, we need to check the alignment.
4508 -- If the alignment of both is specified, we can do it here.
4510 if Serious_Errors_Detected = 0
4511 and then Ekind (Source) in Access_Kind
4512 and then Ekind (Target) in Access_Kind
4513 and then Target_Strict_Alignment
4514 and then Present (Designated_Type (Source))
4515 and then Present (Designated_Type (Target))
4518 D_Source : constant Entity_Id := Designated_Type (Source);
4519 D_Target : constant Entity_Id := Designated_Type (Target);
4522 if Known_Alignment (D_Source)
4523 and then Known_Alignment (D_Target)
4526 Source_Align : constant Uint := Alignment (D_Source);
4527 Target_Align : constant Uint := Alignment (D_Target);
4530 if Source_Align < Target_Align
4531 and then not Is_Tagged_Type (D_Source)
4533 Error_Msg_Uint_1 := Target_Align;
4534 Error_Msg_Uint_2 := Source_Align;
4535 Error_Msg_Node_2 := D_Source;
4537 ("?alignment of & (^) is stricter than " &
4538 "alignment of & (^)!", Enode, D_Target);
4540 if All_Errors_Mode then
4542 ("\?resulting access value may have invalid " &
4543 "alignment!", Enode);
4552 end Validate_Unchecked_Conversions;