1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2008, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree; use Atree;
27 with Checks; use Checks;
28 with Einfo; use Einfo;
29 with Errout; use Errout;
30 with Exp_Tss; use Exp_Tss;
31 with Exp_Util; use Exp_Util;
33 with Lib.Xref; use Lib.Xref;
34 with Namet; use Namet;
35 with Nlists; use Nlists;
36 with Nmake; use Nmake;
38 with Restrict; use Restrict;
39 with Rident; use Rident;
40 with Rtsfind; use Rtsfind;
42 with Sem_Aux; use Sem_Aux;
43 with Sem_Ch8; use Sem_Ch8;
44 with Sem_Eval; use Sem_Eval;
45 with Sem_Res; use Sem_Res;
46 with Sem_Type; use Sem_Type;
47 with Sem_Util; use Sem_Util;
48 with Sem_Warn; use Sem_Warn;
49 with Snames; use Snames;
50 with Stand; use Stand;
51 with Sinfo; use Sinfo;
53 with Targparm; use Targparm;
54 with Ttypes; use Ttypes;
55 with Tbuild; use Tbuild;
56 with Urealp; use Urealp;
58 with GNAT.Heap_Sort_G;
60 package body Sem_Ch13 is
62 SSU : constant Pos := System_Storage_Unit;
63 -- Convenient short hand for commonly used constant
65 -----------------------
66 -- Local Subprograms --
67 -----------------------
69 procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id);
70 -- This routine is called after setting the Esize of type entity Typ.
71 -- The purpose is to deal with the situation where an alignment has been
72 -- inherited from a derived type that is no longer appropriate for the
73 -- new Esize value. In this case, we reset the Alignment to unknown.
75 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id);
76 -- Given two entities for record components or discriminants, checks
77 -- if they have overlapping component clauses and issues errors if so.
79 function Get_Alignment_Value (Expr : Node_Id) return Uint;
80 -- Given the expression for an alignment value, returns the corresponding
81 -- Uint value. If the value is inappropriate, then error messages are
82 -- posted as required, and a value of No_Uint is returned.
84 function Is_Operational_Item (N : Node_Id) return Boolean;
85 -- A specification for a stream attribute is allowed before the full
86 -- type is declared, as explained in AI-00137 and the corrigendum.
87 -- Attributes that do not specify a representation characteristic are
88 -- operational attributes.
90 function Address_Aliased_Entity (N : Node_Id) return Entity_Id;
91 -- If expression N is of the form E'Address, return E
93 procedure New_Stream_Subprogram
98 -- Create a subprogram renaming of a given stream attribute to the
99 -- designated subprogram and then in the tagged case, provide this as a
100 -- primitive operation, or in the non-tagged case make an appropriate TSS
101 -- entry. This is more properly an expansion activity than just semantics,
102 -- but the presence of user-defined stream functions for limited types is a
103 -- legality check, which is why this takes place here rather than in
104 -- exp_ch13, where it was previously. Nam indicates the name of the TSS
105 -- function to be generated.
107 -- To avoid elaboration anomalies with freeze nodes, for untagged types
108 -- we generate both a subprogram declaration and a subprogram renaming
109 -- declaration, so that the attribute specification is handled as a
110 -- renaming_as_body. For tagged types, the specification is one of the
113 ----------------------------------------------
114 -- Table for Validate_Unchecked_Conversions --
115 ----------------------------------------------
117 -- The following table collects unchecked conversions for validation.
118 -- Entries are made by Validate_Unchecked_Conversion and then the
119 -- call to Validate_Unchecked_Conversions does the actual error
120 -- checking and posting of warnings. The reason for this delayed
121 -- processing is to take advantage of back-annotations of size and
122 -- alignment values performed by the back end.
124 -- Note: the reason we store a Source_Ptr value instead of a Node_Id
125 -- is that by the time Validate_Unchecked_Conversions is called, Sprint
126 -- will already have modified all Sloc values if the -gnatD option is set.
128 type UC_Entry is record
129 Eloc : Source_Ptr; -- node used for posting warnings
130 Source : Entity_Id; -- source type for unchecked conversion
131 Target : Entity_Id; -- target type for unchecked conversion
134 package Unchecked_Conversions is new Table.Table (
135 Table_Component_Type => UC_Entry,
136 Table_Index_Type => Int,
137 Table_Low_Bound => 1,
139 Table_Increment => 200,
140 Table_Name => "Unchecked_Conversions");
142 ----------------------------------------
143 -- Table for Validate_Address_Clauses --
144 ----------------------------------------
146 -- If an address clause has the form
148 -- for X'Address use Expr
150 -- where Expr is of the form Y'Address or recursively is a reference
151 -- to a constant of either of these forms, and X and Y are entities of
152 -- objects, then if Y has a smaller alignment than X, that merits a
153 -- warning about possible bad alignment. The following table collects
154 -- address clauses of this kind. We put these in a table so that they
155 -- can be checked after the back end has completed annotation of the
156 -- alignments of objects, since we can catch more cases that way.
158 type Address_Clause_Check_Record is record
160 -- The address clause
163 -- The entity of the object overlaying Y
166 -- The entity of the object being overlaid
169 package Address_Clause_Checks is new Table.Table (
170 Table_Component_Type => Address_Clause_Check_Record,
171 Table_Index_Type => Int,
172 Table_Low_Bound => 1,
174 Table_Increment => 200,
175 Table_Name => "Address_Clause_Checks");
177 ----------------------------
178 -- Address_Aliased_Entity --
179 ----------------------------
181 function Address_Aliased_Entity (N : Node_Id) return Entity_Id is
183 if Nkind (N) = N_Attribute_Reference
184 and then Attribute_Name (N) = Name_Address
191 while Nkind_In (P, N_Selected_Component, N_Indexed_Component) loop
195 if Is_Entity_Name (P) then
202 end Address_Aliased_Entity;
204 -----------------------------------------
205 -- Adjust_Record_For_Reverse_Bit_Order --
206 -----------------------------------------
208 procedure Adjust_Record_For_Reverse_Bit_Order (R : Entity_Id) is
209 Max_Machine_Scalar_Size : constant Uint :=
211 (Standard_Long_Long_Integer_Size);
212 -- We use this as the maximum machine scalar size in the sense of AI-133
216 SSU : constant Uint := UI_From_Int (System_Storage_Unit);
219 -- This first loop through components does two things. First it deals
220 -- with the case of components with component clauses whose length is
221 -- greater than the maximum machine scalar size (either accepting them
222 -- or rejecting as needed). Second, it counts the number of components
223 -- with component clauses whose length does not exceed this maximum for
227 Comp := First_Component_Or_Discriminant (R);
228 while Present (Comp) loop
230 CC : constant Node_Id := Component_Clause (Comp);
235 Fbit : constant Uint := Static_Integer (First_Bit (CC));
238 -- Case of component with size > max machine scalar
240 if Esize (Comp) > Max_Machine_Scalar_Size then
242 -- Must begin on byte boundary
244 if Fbit mod SSU /= 0 then
246 ("illegal first bit value for reverse bit order",
248 Error_Msg_Uint_1 := SSU;
249 Error_Msg_Uint_2 := Max_Machine_Scalar_Size;
252 ("\must be a multiple of ^ if size greater than ^",
255 -- Must end on byte boundary
257 elsif Esize (Comp) mod SSU /= 0 then
259 ("illegal last bit value for reverse bit order",
261 Error_Msg_Uint_1 := SSU;
262 Error_Msg_Uint_2 := Max_Machine_Scalar_Size;
265 ("\must be a multiple of ^ if size greater than ^",
268 -- OK, give warning if enabled
270 elsif Warn_On_Reverse_Bit_Order then
272 ("multi-byte field specified with non-standard"
273 & " Bit_Order?", CC);
275 if Bytes_Big_Endian then
277 ("\bytes are not reversed "
278 & "(component is big-endian)?", CC);
281 ("\bytes are not reversed "
282 & "(component is little-endian)?", CC);
286 -- Case where size is not greater than max machine
287 -- scalar. For now, we just count these.
290 Num_CC := Num_CC + 1;
296 Next_Component_Or_Discriminant (Comp);
299 -- We need to sort the component clauses on the basis of the Position
300 -- values in the clause, so we can group clauses with the same Position.
301 -- together to determine the relevant machine scalar size.
304 Comps : array (0 .. Num_CC) of Entity_Id;
305 -- Array to collect component and discriminant entities. The data
306 -- starts at index 1, the 0'th entry is for the sort routine.
308 function CP_Lt (Op1, Op2 : Natural) return Boolean;
309 -- Compare routine for Sort
311 procedure CP_Move (From : Natural; To : Natural);
312 -- Move routine for Sort
314 package Sorting is new GNAT.Heap_Sort_G (CP_Move, CP_Lt);
318 -- Start and stop positions in component list of set of components
319 -- with the same starting position (that constitute components in
320 -- a single machine scalar).
323 -- Maximum last bit value of any component in this set
326 -- Corresponding machine scalar size
332 function CP_Lt (Op1, Op2 : Natural) return Boolean is
334 return Position (Component_Clause (Comps (Op1))) <
335 Position (Component_Clause (Comps (Op2)));
342 procedure CP_Move (From : Natural; To : Natural) is
344 Comps (To) := Comps (From);
348 -- Collect the component clauses
351 Comp := First_Component_Or_Discriminant (R);
352 while Present (Comp) loop
353 if Present (Component_Clause (Comp))
354 and then Esize (Comp) <= Max_Machine_Scalar_Size
356 Num_CC := Num_CC + 1;
357 Comps (Num_CC) := Comp;
360 Next_Component_Or_Discriminant (Comp);
363 -- Sort by ascending position number
365 Sorting.Sort (Num_CC);
367 -- We now have all the components whose size does not exceed the max
368 -- machine scalar value, sorted by starting position. In this loop
369 -- we gather groups of clauses starting at the same position, to
370 -- process them in accordance with Ada 2005 AI-133.
373 while Stop < Num_CC loop
377 Static_Integer (Last_Bit (Component_Clause (Comps (Start))));
378 while Stop < Num_CC loop
380 (Position (Component_Clause (Comps (Stop + 1)))) =
382 (Position (Component_Clause (Comps (Stop))))
389 (Last_Bit (Component_Clause (Comps (Stop)))));
395 -- Now we have a group of component clauses from Start to Stop
396 -- whose positions are identical, and MaxL is the maximum last bit
397 -- value of any of these components.
399 -- We need to determine the corresponding machine scalar size.
400 -- This loop assumes that machine scalar sizes are even, and that
401 -- each possible machine scalar has twice as many bits as the
404 MSS := Max_Machine_Scalar_Size;
406 and then (MSS / 2) >= SSU
407 and then (MSS / 2) > MaxL
412 -- Here is where we fix up the Component_Bit_Offset value to
413 -- account for the reverse bit order. Some examples of what needs
414 -- to be done for the case of a machine scalar size of 8 are:
416 -- First_Bit .. Last_Bit Component_Bit_Offset
428 -- The general rule is that the first bit is obtained by
429 -- subtracting the old ending bit from machine scalar size - 1.
431 for C in Start .. Stop loop
433 Comp : constant Entity_Id := Comps (C);
434 CC : constant Node_Id := Component_Clause (Comp);
435 LB : constant Uint := Static_Integer (Last_Bit (CC));
436 NFB : constant Uint := MSS - Uint_1 - LB;
437 NLB : constant Uint := NFB + Esize (Comp) - 1;
438 Pos : constant Uint := Static_Integer (Position (CC));
441 if Warn_On_Reverse_Bit_Order then
442 Error_Msg_Uint_1 := MSS;
444 ("info: reverse bit order in machine " &
445 "scalar of length^?", First_Bit (CC));
446 Error_Msg_Uint_1 := NFB;
447 Error_Msg_Uint_2 := NLB;
449 if Bytes_Big_Endian then
451 ("?\info: big-endian range for "
452 & "component & is ^ .. ^",
453 First_Bit (CC), Comp);
456 ("?\info: little-endian range "
457 & "for component & is ^ .. ^",
458 First_Bit (CC), Comp);
462 Set_Component_Bit_Offset (Comp, Pos * SSU + NFB);
463 Set_Normalized_First_Bit (Comp, NFB mod SSU);
468 end Adjust_Record_For_Reverse_Bit_Order;
470 --------------------------------------
471 -- Alignment_Check_For_Esize_Change --
472 --------------------------------------
474 procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id) is
476 -- If the alignment is known, and not set by a rep clause, and is
477 -- inconsistent with the size being set, then reset it to unknown,
478 -- we assume in this case that the size overrides the inherited
479 -- alignment, and that the alignment must be recomputed.
481 if Known_Alignment (Typ)
482 and then not Has_Alignment_Clause (Typ)
483 and then Esize (Typ) mod (Alignment (Typ) * SSU) /= 0
485 Init_Alignment (Typ);
487 end Alignment_Check_For_Esize_Change;
489 -----------------------
490 -- Analyze_At_Clause --
491 -----------------------
493 -- An at clause is replaced by the corresponding Address attribute
494 -- definition clause that is the preferred approach in Ada 95.
496 procedure Analyze_At_Clause (N : Node_Id) is
497 CS : constant Boolean := Comes_From_Source (N);
500 -- This is an obsolescent feature
502 Check_Restriction (No_Obsolescent_Features, N);
504 if Warn_On_Obsolescent_Feature then
506 ("at clause is an obsolescent feature (RM J.7(2))?", N);
508 ("\use address attribute definition clause instead?", N);
511 -- Rewrite as address clause
514 Make_Attribute_Definition_Clause (Sloc (N),
515 Name => Identifier (N),
516 Chars => Name_Address,
517 Expression => Expression (N)));
519 -- We preserve Comes_From_Source, since logically the clause still
520 -- comes from the source program even though it is changed in form.
522 Set_Comes_From_Source (N, CS);
524 -- Analyze rewritten clause
526 Analyze_Attribute_Definition_Clause (N);
527 end Analyze_At_Clause;
529 -----------------------------------------
530 -- Analyze_Attribute_Definition_Clause --
531 -----------------------------------------
533 procedure Analyze_Attribute_Definition_Clause (N : Node_Id) is
534 Loc : constant Source_Ptr := Sloc (N);
535 Nam : constant Node_Id := Name (N);
536 Attr : constant Name_Id := Chars (N);
537 Expr : constant Node_Id := Expression (N);
538 Id : constant Attribute_Id := Get_Attribute_Id (Attr);
542 FOnly : Boolean := False;
543 -- Reset to True for subtype specific attribute (Alignment, Size)
544 -- and for stream attributes, i.e. those cases where in the call
545 -- to Rep_Item_Too_Late, FOnly is set True so that only the freezing
546 -- rules are checked. Note that the case of stream attributes is not
547 -- clear from the RM, but see AI95-00137. Also, the RM seems to
548 -- disallow Storage_Size for derived task types, but that is also
549 -- clearly unintentional.
551 procedure Analyze_Stream_TSS_Definition (TSS_Nam : TSS_Name_Type);
552 -- Common processing for 'Read, 'Write, 'Input and 'Output attribute
553 -- definition clauses.
555 -----------------------------------
556 -- Analyze_Stream_TSS_Definition --
557 -----------------------------------
559 procedure Analyze_Stream_TSS_Definition (TSS_Nam : TSS_Name_Type) is
560 Subp : Entity_Id := Empty;
565 Is_Read : constant Boolean := (TSS_Nam = TSS_Stream_Read);
567 function Has_Good_Profile (Subp : Entity_Id) return Boolean;
568 -- Return true if the entity is a subprogram with an appropriate
569 -- profile for the attribute being defined.
571 ----------------------
572 -- Has_Good_Profile --
573 ----------------------
575 function Has_Good_Profile (Subp : Entity_Id) return Boolean is
577 Is_Function : constant Boolean := (TSS_Nam = TSS_Stream_Input);
578 Expected_Ekind : constant array (Boolean) of Entity_Kind :=
579 (False => E_Procedure, True => E_Function);
583 if Ekind (Subp) /= Expected_Ekind (Is_Function) then
587 F := First_Formal (Subp);
590 or else Ekind (Etype (F)) /= E_Anonymous_Access_Type
591 or else Designated_Type (Etype (F)) /=
592 Class_Wide_Type (RTE (RE_Root_Stream_Type))
597 if not Is_Function then
601 Expected_Mode : constant array (Boolean) of Entity_Kind :=
602 (False => E_In_Parameter,
603 True => E_Out_Parameter);
605 if Parameter_Mode (F) /= Expected_Mode (Is_Read) then
616 return Base_Type (Typ) = Base_Type (Ent)
617 and then No (Next_Formal (F));
618 end Has_Good_Profile;
620 -- Start of processing for Analyze_Stream_TSS_Definition
625 if not Is_Type (U_Ent) then
626 Error_Msg_N ("local name must be a subtype", Nam);
630 Pnam := TSS (Base_Type (U_Ent), TSS_Nam);
632 -- If Pnam is present, it can be either inherited from an ancestor
633 -- type (in which case it is legal to redefine it for this type), or
634 -- be a previous definition of the attribute for the same type (in
635 -- which case it is illegal).
637 -- In the first case, it will have been analyzed already, and we
638 -- can check that its profile does not match the expected profile
639 -- for a stream attribute of U_Ent. In the second case, either Pnam
640 -- has been analyzed (and has the expected profile), or it has not
641 -- been analyzed yet (case of a type that has not been frozen yet
642 -- and for which the stream attribute has been set using Set_TSS).
645 and then (No (First_Entity (Pnam)) or else Has_Good_Profile (Pnam))
647 Error_Msg_Sloc := Sloc (Pnam);
648 Error_Msg_Name_1 := Attr;
649 Error_Msg_N ("% attribute already defined #", Nam);
655 if Is_Entity_Name (Expr) then
656 if not Is_Overloaded (Expr) then
657 if Has_Good_Profile (Entity (Expr)) then
658 Subp := Entity (Expr);
662 Get_First_Interp (Expr, I, It);
663 while Present (It.Nam) loop
664 if Has_Good_Profile (It.Nam) then
669 Get_Next_Interp (I, It);
674 if Present (Subp) then
675 if Is_Abstract_Subprogram (Subp) then
676 Error_Msg_N ("stream subprogram must not be abstract", Expr);
680 Set_Entity (Expr, Subp);
681 Set_Etype (Expr, Etype (Subp));
683 New_Stream_Subprogram (N, U_Ent, Subp, TSS_Nam);
686 Error_Msg_Name_1 := Attr;
687 Error_Msg_N ("incorrect expression for% attribute", Expr);
689 end Analyze_Stream_TSS_Definition;
691 -- Start of processing for Analyze_Attribute_Definition_Clause
694 if Ignore_Rep_Clauses then
695 Rewrite (N, Make_Null_Statement (Sloc (N)));
702 if Rep_Item_Too_Early (Ent, N) then
706 -- Rep clause applies to full view of incomplete type or private type if
707 -- we have one (if not, this is a premature use of the type). However,
708 -- certain semantic checks need to be done on the specified entity (i.e.
709 -- the private view), so we save it in Ent.
711 if Is_Private_Type (Ent)
712 and then Is_Derived_Type (Ent)
713 and then not Is_Tagged_Type (Ent)
714 and then No (Full_View (Ent))
716 -- If this is a private type whose completion is a derivation from
717 -- another private type, there is no full view, and the attribute
718 -- belongs to the type itself, not its underlying parent.
722 elsif Ekind (Ent) = E_Incomplete_Type then
724 -- The attribute applies to the full view, set the entity of the
725 -- attribute definition accordingly.
727 Ent := Underlying_Type (Ent);
729 Set_Entity (Nam, Ent);
732 U_Ent := Underlying_Type (Ent);
735 -- Complete other routine error checks
737 if Etype (Nam) = Any_Type then
740 elsif Scope (Ent) /= Current_Scope then
741 Error_Msg_N ("entity must be declared in this scope", Nam);
744 elsif No (U_Ent) then
747 elsif Is_Type (U_Ent)
748 and then not Is_First_Subtype (U_Ent)
749 and then Id /= Attribute_Object_Size
750 and then Id /= Attribute_Value_Size
751 and then not From_At_Mod (N)
753 Error_Msg_N ("cannot specify attribute for subtype", Nam);
757 -- Switch on particular attribute
765 -- Address attribute definition clause
767 when Attribute_Address => Address : begin
769 -- A little error check, catch for X'Address use X'Address;
771 if Nkind (Nam) = N_Identifier
772 and then Nkind (Expr) = N_Attribute_Reference
773 and then Attribute_Name (Expr) = Name_Address
774 and then Nkind (Prefix (Expr)) = N_Identifier
775 and then Chars (Nam) = Chars (Prefix (Expr))
778 ("address for & is self-referencing", Prefix (Expr), Ent);
782 -- Not that special case, carry on with analysis of expression
784 Analyze_And_Resolve (Expr, RTE (RE_Address));
786 if Present (Address_Clause (U_Ent)) then
787 Error_Msg_N ("address already given for &", Nam);
789 -- Case of address clause for subprogram
791 elsif Is_Subprogram (U_Ent) then
792 if Has_Homonym (U_Ent) then
794 ("address clause cannot be given " &
795 "for overloaded subprogram",
800 -- For subprograms, all address clauses are permitted, and we
801 -- mark the subprogram as having a deferred freeze so that Gigi
802 -- will not elaborate it too soon.
804 -- Above needs more comments, what is too soon about???
806 Set_Has_Delayed_Freeze (U_Ent);
808 -- Case of address clause for entry
810 elsif Ekind (U_Ent) = E_Entry then
811 if Nkind (Parent (N)) = N_Task_Body then
813 ("entry address must be specified in task spec", Nam);
817 -- For entries, we require a constant address
819 Check_Constant_Address_Clause (Expr, U_Ent);
821 -- Special checks for task types
823 if Is_Task_Type (Scope (U_Ent))
824 and then Comes_From_Source (Scope (U_Ent))
827 ("?entry address declared for entry in task type", N);
829 ("\?only one task can be declared of this type", N);
832 -- Entry address clauses are obsolescent
834 Check_Restriction (No_Obsolescent_Features, N);
836 if Warn_On_Obsolescent_Feature then
838 ("attaching interrupt to task entry is an " &
839 "obsolescent feature (RM J.7.1)?", N);
841 ("\use interrupt procedure instead?", N);
844 -- Case of an address clause for a controlled object which we
845 -- consider to be erroneous.
847 elsif Is_Controlled (Etype (U_Ent))
848 or else Has_Controlled_Component (Etype (U_Ent))
851 ("?controlled object& must not be overlaid", Nam, U_Ent);
853 ("\?Program_Error will be raised at run time", Nam);
854 Insert_Action (Declaration_Node (U_Ent),
855 Make_Raise_Program_Error (Loc,
856 Reason => PE_Overlaid_Controlled_Object));
859 -- Case of address clause for a (non-controlled) object
862 Ekind (U_Ent) = E_Variable
864 Ekind (U_Ent) = E_Constant
867 Expr : constant Node_Id := Expression (N);
868 Aent : constant Entity_Id := Address_Aliased_Entity (Expr);
869 Ent_Y : constant Entity_Id := Find_Overlaid_Object (N);
872 -- Exported variables cannot have an address clause,
873 -- because this cancels the effect of the pragma Export
875 if Is_Exported (U_Ent) then
877 ("cannot export object with address clause", Nam);
880 -- Overlaying controlled objects is erroneous
883 and then (Has_Controlled_Component (Etype (Aent))
884 or else Is_Controlled (Etype (Aent)))
887 ("?cannot overlay with controlled object", Expr);
889 ("\?Program_Error will be raised at run time", Expr);
890 Insert_Action (Declaration_Node (U_Ent),
891 Make_Raise_Program_Error (Loc,
892 Reason => PE_Overlaid_Controlled_Object));
896 and then Ekind (U_Ent) = E_Constant
897 and then Ekind (Aent) /= E_Constant
899 Error_Msg_N ("constant overlays a variable?", Expr);
901 elsif Present (Renamed_Object (U_Ent)) then
903 ("address clause not allowed"
904 & " for a renaming declaration (RM 13.1(6))", Nam);
907 -- Imported variables can have an address clause, but then
908 -- the import is pretty meaningless except to suppress
909 -- initializations, so we do not need such variables to
910 -- be statically allocated (and in fact it causes trouble
911 -- if the address clause is a local value).
913 elsif Is_Imported (U_Ent) then
914 Set_Is_Statically_Allocated (U_Ent, False);
917 -- We mark a possible modification of a variable with an
918 -- address clause, since it is likely aliasing is occurring.
920 Note_Possible_Modification (Nam, Sure => False);
922 -- Here we are checking for explicit overlap of one variable
923 -- by another, and if we find this then mark the overlapped
924 -- variable as also being volatile to prevent unwanted
927 if Present (Ent_Y) then
928 Set_Treat_As_Volatile (Ent_Y);
931 -- Legality checks on the address clause for initialized
932 -- objects is deferred until the freeze point, because
933 -- a subsequent pragma might indicate that the object is
934 -- imported and thus not initialized.
936 Set_Has_Delayed_Freeze (U_Ent);
938 if Is_Exported (U_Ent) then
940 ("& cannot be exported if an address clause is given",
943 ("\define and export a variable " &
944 "that holds its address instead",
948 -- Entity has delayed freeze, so we will generate an
949 -- alignment check at the freeze point unless suppressed.
951 if not Range_Checks_Suppressed (U_Ent)
952 and then not Alignment_Checks_Suppressed (U_Ent)
954 Set_Check_Address_Alignment (N);
957 -- Kill the size check code, since we are not allocating
958 -- the variable, it is somewhere else.
960 Kill_Size_Check_Code (U_Ent);
963 -- If the address clause is of the form:
965 -- for Y'Address use X'Address
969 -- Const : constant Address := X'Address;
971 -- for Y'Address use Const;
973 -- then we make an entry in the table for checking the size and
974 -- alignment of the overlaying variable. We defer this check
975 -- till after code generation to take full advantage of the
976 -- annotation done by the back end. This entry is only made if
977 -- we have not already posted a warning about size/alignment
978 -- (some warnings of this type are posted in Checks), and if
979 -- the address clause comes from source.
981 if Address_Clause_Overlay_Warnings
982 and then Comes_From_Source (N)
985 Ent_X : Entity_Id := Empty;
986 Ent_Y : Entity_Id := Empty;
989 Ent_Y := Find_Overlaid_Object (N);
991 if Present (Ent_Y) and then Is_Entity_Name (Name (N)) then
992 Ent_X := Entity (Name (N));
993 Address_Clause_Checks.Append ((N, Ent_X, Ent_Y));
995 -- If variable overlays a constant view, and we are
996 -- warning on overlays, then mark the variable as
997 -- overlaying a constant (we will give warnings later
998 -- if this variable is assigned).
1000 if Is_Constant_Object (Ent_Y)
1001 and then Ekind (Ent_X) = E_Variable
1003 Set_Overlays_Constant (Ent_X);
1009 -- Not a valid entity for an address clause
1012 Error_Msg_N ("address cannot be given for &", Nam);
1020 -- Alignment attribute definition clause
1022 when Attribute_Alignment => Alignment_Block : declare
1023 Align : constant Uint := Get_Alignment_Value (Expr);
1028 if not Is_Type (U_Ent)
1029 and then Ekind (U_Ent) /= E_Variable
1030 and then Ekind (U_Ent) /= E_Constant
1032 Error_Msg_N ("alignment cannot be given for &", Nam);
1034 elsif Has_Alignment_Clause (U_Ent) then
1035 Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent));
1036 Error_Msg_N ("alignment clause previously given#", N);
1038 elsif Align /= No_Uint then
1039 Set_Has_Alignment_Clause (U_Ent);
1040 Set_Alignment (U_Ent, Align);
1042 end Alignment_Block;
1048 -- Bit_Order attribute definition clause
1050 when Attribute_Bit_Order => Bit_Order : declare
1052 if not Is_Record_Type (U_Ent) then
1054 ("Bit_Order can only be defined for record type", Nam);
1057 Analyze_And_Resolve (Expr, RTE (RE_Bit_Order));
1059 if Etype (Expr) = Any_Type then
1062 elsif not Is_Static_Expression (Expr) then
1063 Flag_Non_Static_Expr
1064 ("Bit_Order requires static expression!", Expr);
1067 if (Expr_Value (Expr) = 0) /= Bytes_Big_Endian then
1068 Set_Reverse_Bit_Order (U_Ent, True);
1074 --------------------
1075 -- Component_Size --
1076 --------------------
1078 -- Component_Size attribute definition clause
1080 when Attribute_Component_Size => Component_Size_Case : declare
1081 Csize : constant Uint := Static_Integer (Expr);
1084 New_Ctyp : Entity_Id;
1088 if not Is_Array_Type (U_Ent) then
1089 Error_Msg_N ("component size requires array type", Nam);
1093 Btype := Base_Type (U_Ent);
1095 if Has_Component_Size_Clause (Btype) then
1097 ("component size clause for& previously given", Nam);
1099 elsif Csize /= No_Uint then
1100 Check_Size (Expr, Component_Type (Btype), Csize, Biased);
1102 if Has_Aliased_Components (Btype)
1105 and then Csize /= 16
1108 ("component size incorrect for aliased components", N);
1112 -- For the biased case, build a declaration for a subtype
1113 -- that will be used to represent the biased subtype that
1114 -- reflects the biased representation of components. We need
1115 -- this subtype to get proper conversions on referencing
1116 -- elements of the array. Note that component size clauses
1117 -- are ignored in VM mode.
1119 if VM_Target = No_VM then
1122 Make_Defining_Identifier (Loc,
1124 New_External_Name (Chars (U_Ent), 'C', 0, 'T'));
1127 Make_Subtype_Declaration (Loc,
1128 Defining_Identifier => New_Ctyp,
1129 Subtype_Indication =>
1130 New_Occurrence_Of (Component_Type (Btype), Loc));
1132 Set_Parent (Decl, N);
1133 Analyze (Decl, Suppress => All_Checks);
1135 Set_Has_Delayed_Freeze (New_Ctyp, False);
1136 Set_Esize (New_Ctyp, Csize);
1137 Set_RM_Size (New_Ctyp, Csize);
1138 Init_Alignment (New_Ctyp);
1139 Set_Has_Biased_Representation (New_Ctyp, True);
1140 Set_Is_Itype (New_Ctyp, True);
1141 Set_Associated_Node_For_Itype (New_Ctyp, U_Ent);
1143 Set_Component_Type (Btype, New_Ctyp);
1145 if Warn_On_Biased_Representation then
1147 ("?component size clause forces biased "
1148 & "representation", N);
1152 Set_Component_Size (Btype, Csize);
1154 -- For VM case, we ignore component size clauses
1157 -- Give a warning unless we are in GNAT mode, in which case
1158 -- the warning is suppressed since it is not useful.
1160 if not GNAT_Mode then
1162 ("?component size ignored in this configuration", N);
1166 Set_Has_Component_Size_Clause (Btype, True);
1167 Set_Has_Non_Standard_Rep (Btype, True);
1169 end Component_Size_Case;
1175 when Attribute_External_Tag => External_Tag :
1177 if not Is_Tagged_Type (U_Ent) then
1178 Error_Msg_N ("should be a tagged type", Nam);
1181 Analyze_And_Resolve (Expr, Standard_String);
1183 if not Is_Static_Expression (Expr) then
1184 Flag_Non_Static_Expr
1185 ("static string required for tag name!", Nam);
1188 if VM_Target = No_VM then
1189 Set_Has_External_Tag_Rep_Clause (U_Ent);
1190 elsif not Inspector_Mode then
1191 Error_Msg_Name_1 := Attr;
1193 ("% attribute unsupported in this configuration", Nam);
1196 if not Is_Library_Level_Entity (U_Ent) then
1198 ("?non-unique external tag supplied for &", N, U_Ent);
1200 ("?\same external tag applies to all subprogram calls", N);
1202 ("?\corresponding internal tag cannot be obtained", N);
1210 when Attribute_Input =>
1211 Analyze_Stream_TSS_Definition (TSS_Stream_Input);
1212 Set_Has_Specified_Stream_Input (Ent);
1218 -- Machine radix attribute definition clause
1220 when Attribute_Machine_Radix => Machine_Radix : declare
1221 Radix : constant Uint := Static_Integer (Expr);
1224 if not Is_Decimal_Fixed_Point_Type (U_Ent) then
1225 Error_Msg_N ("decimal fixed-point type expected for &", Nam);
1227 elsif Has_Machine_Radix_Clause (U_Ent) then
1228 Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent));
1229 Error_Msg_N ("machine radix clause previously given#", N);
1231 elsif Radix /= No_Uint then
1232 Set_Has_Machine_Radix_Clause (U_Ent);
1233 Set_Has_Non_Standard_Rep (Base_Type (U_Ent));
1237 elsif Radix = 10 then
1238 Set_Machine_Radix_10 (U_Ent);
1240 Error_Msg_N ("machine radix value must be 2 or 10", Expr);
1249 -- Object_Size attribute definition clause
1251 when Attribute_Object_Size => Object_Size : declare
1252 Size : constant Uint := Static_Integer (Expr);
1255 pragma Warnings (Off, Biased);
1258 if not Is_Type (U_Ent) then
1259 Error_Msg_N ("Object_Size cannot be given for &", Nam);
1261 elsif Has_Object_Size_Clause (U_Ent) then
1262 Error_Msg_N ("Object_Size already given for &", Nam);
1265 Check_Size (Expr, U_Ent, Size, Biased);
1273 UI_Mod (Size, 64) /= 0
1276 ("Object_Size must be 8, 16, 32, or multiple of 64",
1280 Set_Esize (U_Ent, Size);
1281 Set_Has_Object_Size_Clause (U_Ent);
1282 Alignment_Check_For_Esize_Change (U_Ent);
1290 when Attribute_Output =>
1291 Analyze_Stream_TSS_Definition (TSS_Stream_Output);
1292 Set_Has_Specified_Stream_Output (Ent);
1298 when Attribute_Read =>
1299 Analyze_Stream_TSS_Definition (TSS_Stream_Read);
1300 Set_Has_Specified_Stream_Read (Ent);
1306 -- Size attribute definition clause
1308 when Attribute_Size => Size : declare
1309 Size : constant Uint := Static_Integer (Expr);
1316 if Has_Size_Clause (U_Ent) then
1317 Error_Msg_N ("size already given for &", Nam);
1319 elsif not Is_Type (U_Ent)
1320 and then Ekind (U_Ent) /= E_Variable
1321 and then Ekind (U_Ent) /= E_Constant
1323 Error_Msg_N ("size cannot be given for &", Nam);
1325 elsif Is_Array_Type (U_Ent)
1326 and then not Is_Constrained (U_Ent)
1329 ("size cannot be given for unconstrained array", Nam);
1331 elsif Size /= No_Uint then
1332 if Is_Type (U_Ent) then
1335 Etyp := Etype (U_Ent);
1338 -- Check size, note that Gigi is in charge of checking that the
1339 -- size of an array or record type is OK. Also we do not check
1340 -- the size in the ordinary fixed-point case, since it is too
1341 -- early to do so (there may be subsequent small clause that
1342 -- affects the size). We can check the size if a small clause
1343 -- has already been given.
1345 if not Is_Ordinary_Fixed_Point_Type (U_Ent)
1346 or else Has_Small_Clause (U_Ent)
1348 Check_Size (Expr, Etyp, Size, Biased);
1349 Set_Has_Biased_Representation (U_Ent, Biased);
1351 if Biased and Warn_On_Biased_Representation then
1353 ("?size clause forces biased representation", N);
1357 -- For types set RM_Size and Esize if possible
1359 if Is_Type (U_Ent) then
1360 Set_RM_Size (U_Ent, Size);
1362 -- For scalar types, increase Object_Size to power of 2, but
1363 -- not less than a storage unit in any case (i.e., normally
1364 -- this means it will be byte addressable).
1366 if Is_Scalar_Type (U_Ent) then
1367 if Size <= System_Storage_Unit then
1368 Init_Esize (U_Ent, System_Storage_Unit);
1369 elsif Size <= 16 then
1370 Init_Esize (U_Ent, 16);
1371 elsif Size <= 32 then
1372 Init_Esize (U_Ent, 32);
1374 Set_Esize (U_Ent, (Size + 63) / 64 * 64);
1377 -- For all other types, object size = value size. The
1378 -- backend will adjust as needed.
1381 Set_Esize (U_Ent, Size);
1384 Alignment_Check_For_Esize_Change (U_Ent);
1386 -- For objects, set Esize only
1389 if Is_Elementary_Type (Etyp) then
1390 if Size /= System_Storage_Unit
1392 Size /= System_Storage_Unit * 2
1394 Size /= System_Storage_Unit * 4
1396 Size /= System_Storage_Unit * 8
1398 Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit);
1399 Error_Msg_Uint_2 := Error_Msg_Uint_1 * 8;
1401 ("size for primitive object must be a power of 2"
1402 & " in the range ^-^", N);
1406 Set_Esize (U_Ent, Size);
1409 Set_Has_Size_Clause (U_Ent);
1417 -- Small attribute definition clause
1419 when Attribute_Small => Small : declare
1420 Implicit_Base : constant Entity_Id := Base_Type (U_Ent);
1424 Analyze_And_Resolve (Expr, Any_Real);
1426 if Etype (Expr) = Any_Type then
1429 elsif not Is_Static_Expression (Expr) then
1430 Flag_Non_Static_Expr
1431 ("small requires static expression!", Expr);
1435 Small := Expr_Value_R (Expr);
1437 if Small <= Ureal_0 then
1438 Error_Msg_N ("small value must be greater than zero", Expr);
1444 if not Is_Ordinary_Fixed_Point_Type (U_Ent) then
1446 ("small requires an ordinary fixed point type", Nam);
1448 elsif Has_Small_Clause (U_Ent) then
1449 Error_Msg_N ("small already given for &", Nam);
1451 elsif Small > Delta_Value (U_Ent) then
1453 ("small value must not be greater then delta value", Nam);
1456 Set_Small_Value (U_Ent, Small);
1457 Set_Small_Value (Implicit_Base, Small);
1458 Set_Has_Small_Clause (U_Ent);
1459 Set_Has_Small_Clause (Implicit_Base);
1460 Set_Has_Non_Standard_Rep (Implicit_Base);
1468 -- Storage_Pool attribute definition clause
1470 when Attribute_Storage_Pool => Storage_Pool : declare
1475 if Ekind (U_Ent) = E_Access_Subprogram_Type then
1477 ("storage pool cannot be given for access-to-subprogram type",
1481 elsif Ekind (U_Ent) /= E_Access_Type
1482 and then Ekind (U_Ent) /= E_General_Access_Type
1485 ("storage pool can only be given for access types", Nam);
1488 elsif Is_Derived_Type (U_Ent) then
1490 ("storage pool cannot be given for a derived access type",
1493 elsif Has_Storage_Size_Clause (U_Ent) then
1494 Error_Msg_N ("storage size already given for &", Nam);
1497 elsif Present (Associated_Storage_Pool (U_Ent)) then
1498 Error_Msg_N ("storage pool already given for &", Nam);
1503 (Expr, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
1505 if not Denotes_Variable (Expr) then
1506 Error_Msg_N ("storage pool must be a variable", Expr);
1510 if Nkind (Expr) = N_Type_Conversion then
1511 T := Etype (Expression (Expr));
1516 -- The Stack_Bounded_Pool is used internally for implementing
1517 -- access types with a Storage_Size. Since it only work
1518 -- properly when used on one specific type, we need to check
1519 -- that it is not hijacked improperly:
1520 -- type T is access Integer;
1521 -- for T'Storage_Size use n;
1522 -- type Q is access Float;
1523 -- for Q'Storage_Size use T'Storage_Size; -- incorrect
1525 if RTE_Available (RE_Stack_Bounded_Pool)
1526 and then Base_Type (T) = RTE (RE_Stack_Bounded_Pool)
1528 Error_Msg_N ("non-shareable internal Pool", Expr);
1532 -- If the argument is a name that is not an entity name, then
1533 -- we construct a renaming operation to define an entity of
1534 -- type storage pool.
1536 if not Is_Entity_Name (Expr)
1537 and then Is_Object_Reference (Expr)
1540 Make_Defining_Identifier (Loc,
1541 Chars => New_Internal_Name ('P'));
1544 Rnode : constant Node_Id :=
1545 Make_Object_Renaming_Declaration (Loc,
1546 Defining_Identifier => Pool,
1548 New_Occurrence_Of (Etype (Expr), Loc),
1552 Insert_Before (N, Rnode);
1554 Set_Associated_Storage_Pool (U_Ent, Pool);
1557 elsif Is_Entity_Name (Expr) then
1558 Pool := Entity (Expr);
1560 -- If pool is a renamed object, get original one. This can
1561 -- happen with an explicit renaming, and within instances.
1563 while Present (Renamed_Object (Pool))
1564 and then Is_Entity_Name (Renamed_Object (Pool))
1566 Pool := Entity (Renamed_Object (Pool));
1569 if Present (Renamed_Object (Pool))
1570 and then Nkind (Renamed_Object (Pool)) = N_Type_Conversion
1571 and then Is_Entity_Name (Expression (Renamed_Object (Pool)))
1573 Pool := Entity (Expression (Renamed_Object (Pool)));
1576 Set_Associated_Storage_Pool (U_Ent, Pool);
1578 elsif Nkind (Expr) = N_Type_Conversion
1579 and then Is_Entity_Name (Expression (Expr))
1580 and then Nkind (Original_Node (Expr)) = N_Attribute_Reference
1582 Pool := Entity (Expression (Expr));
1583 Set_Associated_Storage_Pool (U_Ent, Pool);
1586 Error_Msg_N ("incorrect reference to a Storage Pool", Expr);
1595 -- Storage_Size attribute definition clause
1597 when Attribute_Storage_Size => Storage_Size : declare
1598 Btype : constant Entity_Id := Base_Type (U_Ent);
1602 if Is_Task_Type (U_Ent) then
1603 Check_Restriction (No_Obsolescent_Features, N);
1605 if Warn_On_Obsolescent_Feature then
1607 ("storage size clause for task is an " &
1608 "obsolescent feature (RM J.9)?", N);
1610 ("\use Storage_Size pragma instead?", N);
1616 if not Is_Access_Type (U_Ent)
1617 and then Ekind (U_Ent) /= E_Task_Type
1619 Error_Msg_N ("storage size cannot be given for &", Nam);
1621 elsif Is_Access_Type (U_Ent) and Is_Derived_Type (U_Ent) then
1623 ("storage size cannot be given for a derived access type",
1626 elsif Has_Storage_Size_Clause (Btype) then
1627 Error_Msg_N ("storage size already given for &", Nam);
1630 Analyze_And_Resolve (Expr, Any_Integer);
1632 if Is_Access_Type (U_Ent) then
1633 if Present (Associated_Storage_Pool (U_Ent)) then
1634 Error_Msg_N ("storage pool already given for &", Nam);
1638 if Compile_Time_Known_Value (Expr)
1639 and then Expr_Value (Expr) = 0
1641 Set_No_Pool_Assigned (Btype);
1644 else -- Is_Task_Type (U_Ent)
1645 Sprag := Get_Rep_Pragma (Btype, Name_Storage_Size);
1647 if Present (Sprag) then
1648 Error_Msg_Sloc := Sloc (Sprag);
1650 ("Storage_Size already specified#", Nam);
1655 Set_Has_Storage_Size_Clause (Btype);
1663 when Attribute_Stream_Size => Stream_Size : declare
1664 Size : constant Uint := Static_Integer (Expr);
1667 if Ada_Version <= Ada_95 then
1668 Check_Restriction (No_Implementation_Attributes, N);
1671 if Has_Stream_Size_Clause (U_Ent) then
1672 Error_Msg_N ("Stream_Size already given for &", Nam);
1674 elsif Is_Elementary_Type (U_Ent) then
1675 if Size /= System_Storage_Unit
1677 Size /= System_Storage_Unit * 2
1679 Size /= System_Storage_Unit * 4
1681 Size /= System_Storage_Unit * 8
1683 Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit);
1685 ("stream size for elementary type must be a"
1686 & " power of 2 and at least ^", N);
1688 elsif RM_Size (U_Ent) > Size then
1689 Error_Msg_Uint_1 := RM_Size (U_Ent);
1691 ("stream size for elementary type must be a"
1692 & " power of 2 and at least ^", N);
1695 Set_Has_Stream_Size_Clause (U_Ent);
1698 Error_Msg_N ("Stream_Size cannot be given for &", Nam);
1706 -- Value_Size attribute definition clause
1708 when Attribute_Value_Size => Value_Size : declare
1709 Size : constant Uint := Static_Integer (Expr);
1713 if not Is_Type (U_Ent) then
1714 Error_Msg_N ("Value_Size cannot be given for &", Nam);
1717 (Get_Attribute_Definition_Clause
1718 (U_Ent, Attribute_Value_Size))
1720 Error_Msg_N ("Value_Size already given for &", Nam);
1722 elsif Is_Array_Type (U_Ent)
1723 and then not Is_Constrained (U_Ent)
1726 ("Value_Size cannot be given for unconstrained array", Nam);
1729 if Is_Elementary_Type (U_Ent) then
1730 Check_Size (Expr, U_Ent, Size, Biased);
1731 Set_Has_Biased_Representation (U_Ent, Biased);
1733 if Biased and Warn_On_Biased_Representation then
1735 ("?value size clause forces biased representation", N);
1739 Set_RM_Size (U_Ent, Size);
1747 when Attribute_Write =>
1748 Analyze_Stream_TSS_Definition (TSS_Stream_Write);
1749 Set_Has_Specified_Stream_Write (Ent);
1751 -- All other attributes cannot be set
1755 ("attribute& cannot be set with definition clause", N);
1758 -- The test for the type being frozen must be performed after
1759 -- any expression the clause has been analyzed since the expression
1760 -- itself might cause freezing that makes the clause illegal.
1762 if Rep_Item_Too_Late (U_Ent, N, FOnly) then
1765 end Analyze_Attribute_Definition_Clause;
1767 ----------------------------
1768 -- Analyze_Code_Statement --
1769 ----------------------------
1771 procedure Analyze_Code_Statement (N : Node_Id) is
1772 HSS : constant Node_Id := Parent (N);
1773 SBody : constant Node_Id := Parent (HSS);
1774 Subp : constant Entity_Id := Current_Scope;
1781 -- Analyze and check we get right type, note that this implements the
1782 -- requirement (RM 13.8(1)) that Machine_Code be with'ed, since that
1783 -- is the only way that Asm_Insn could possibly be visible.
1785 Analyze_And_Resolve (Expression (N));
1787 if Etype (Expression (N)) = Any_Type then
1789 elsif Etype (Expression (N)) /= RTE (RE_Asm_Insn) then
1790 Error_Msg_N ("incorrect type for code statement", N);
1794 Check_Code_Statement (N);
1796 -- Make sure we appear in the handled statement sequence of a
1797 -- subprogram (RM 13.8(3)).
1799 if Nkind (HSS) /= N_Handled_Sequence_Of_Statements
1800 or else Nkind (SBody) /= N_Subprogram_Body
1803 ("code statement can only appear in body of subprogram", N);
1807 -- Do remaining checks (RM 13.8(3)) if not already done
1809 if not Is_Machine_Code_Subprogram (Subp) then
1810 Set_Is_Machine_Code_Subprogram (Subp);
1812 -- No exception handlers allowed
1814 if Present (Exception_Handlers (HSS)) then
1816 ("exception handlers not permitted in machine code subprogram",
1817 First (Exception_Handlers (HSS)));
1820 -- No declarations other than use clauses and pragmas (we allow
1821 -- certain internally generated declarations as well).
1823 Decl := First (Declarations (SBody));
1824 while Present (Decl) loop
1825 DeclO := Original_Node (Decl);
1826 if Comes_From_Source (DeclO)
1827 and not Nkind_In (DeclO, N_Pragma,
1828 N_Use_Package_Clause,
1830 N_Implicit_Label_Declaration)
1833 ("this declaration not allowed in machine code subprogram",
1840 -- No statements other than code statements, pragmas, and labels.
1841 -- Again we allow certain internally generated statements.
1843 Stmt := First (Statements (HSS));
1844 while Present (Stmt) loop
1845 StmtO := Original_Node (Stmt);
1846 if Comes_From_Source (StmtO)
1847 and then not Nkind_In (StmtO, N_Pragma,
1852 ("this statement is not allowed in machine code subprogram",
1859 end Analyze_Code_Statement;
1861 -----------------------------------------------
1862 -- Analyze_Enumeration_Representation_Clause --
1863 -----------------------------------------------
1865 procedure Analyze_Enumeration_Representation_Clause (N : Node_Id) is
1866 Ident : constant Node_Id := Identifier (N);
1867 Aggr : constant Node_Id := Array_Aggregate (N);
1868 Enumtype : Entity_Id;
1874 Err : Boolean := False;
1876 Lo : constant Uint := Expr_Value (Type_Low_Bound (Universal_Integer));
1877 Hi : constant Uint := Expr_Value (Type_High_Bound (Universal_Integer));
1882 if Ignore_Rep_Clauses then
1886 -- First some basic error checks
1889 Enumtype := Entity (Ident);
1891 if Enumtype = Any_Type
1892 or else Rep_Item_Too_Early (Enumtype, N)
1896 Enumtype := Underlying_Type (Enumtype);
1899 if not Is_Enumeration_Type (Enumtype) then
1901 ("enumeration type required, found}",
1902 Ident, First_Subtype (Enumtype));
1906 -- Ignore rep clause on generic actual type. This will already have
1907 -- been flagged on the template as an error, and this is the safest
1908 -- way to ensure we don't get a junk cascaded message in the instance.
1910 if Is_Generic_Actual_Type (Enumtype) then
1913 -- Type must be in current scope
1915 elsif Scope (Enumtype) /= Current_Scope then
1916 Error_Msg_N ("type must be declared in this scope", Ident);
1919 -- Type must be a first subtype
1921 elsif not Is_First_Subtype (Enumtype) then
1922 Error_Msg_N ("cannot give enumeration rep clause for subtype", N);
1925 -- Ignore duplicate rep clause
1927 elsif Has_Enumeration_Rep_Clause (Enumtype) then
1928 Error_Msg_N ("duplicate enumeration rep clause ignored", N);
1931 -- Don't allow rep clause for standard [wide_[wide_]]character
1933 elsif Is_Standard_Character_Type (Enumtype) then
1934 Error_Msg_N ("enumeration rep clause not allowed for this type", N);
1937 -- Check that the expression is a proper aggregate (no parentheses)
1939 elsif Paren_Count (Aggr) /= 0 then
1941 ("extra parentheses surrounding aggregate not allowed",
1945 -- All tests passed, so set rep clause in place
1948 Set_Has_Enumeration_Rep_Clause (Enumtype);
1949 Set_Has_Enumeration_Rep_Clause (Base_Type (Enumtype));
1952 -- Now we process the aggregate. Note that we don't use the normal
1953 -- aggregate code for this purpose, because we don't want any of the
1954 -- normal expansion activities, and a number of special semantic
1955 -- rules apply (including the component type being any integer type)
1957 Elit := First_Literal (Enumtype);
1959 -- First the positional entries if any
1961 if Present (Expressions (Aggr)) then
1962 Expr := First (Expressions (Aggr));
1963 while Present (Expr) loop
1965 Error_Msg_N ("too many entries in aggregate", Expr);
1969 Val := Static_Integer (Expr);
1971 -- Err signals that we found some incorrect entries processing
1972 -- the list. The final checks for completeness and ordering are
1973 -- skipped in this case.
1975 if Val = No_Uint then
1977 elsif Val < Lo or else Hi < Val then
1978 Error_Msg_N ("value outside permitted range", Expr);
1982 Set_Enumeration_Rep (Elit, Val);
1983 Set_Enumeration_Rep_Expr (Elit, Expr);
1989 -- Now process the named entries if present
1991 if Present (Component_Associations (Aggr)) then
1992 Assoc := First (Component_Associations (Aggr));
1993 while Present (Assoc) loop
1994 Choice := First (Choices (Assoc));
1996 if Present (Next (Choice)) then
1998 ("multiple choice not allowed here", Next (Choice));
2002 if Nkind (Choice) = N_Others_Choice then
2003 Error_Msg_N ("others choice not allowed here", Choice);
2006 elsif Nkind (Choice) = N_Range then
2007 -- ??? should allow zero/one element range here
2008 Error_Msg_N ("range not allowed here", Choice);
2012 Analyze_And_Resolve (Choice, Enumtype);
2014 if Is_Entity_Name (Choice)
2015 and then Is_Type (Entity (Choice))
2017 Error_Msg_N ("subtype name not allowed here", Choice);
2019 -- ??? should allow static subtype with zero/one entry
2021 elsif Etype (Choice) = Base_Type (Enumtype) then
2022 if not Is_Static_Expression (Choice) then
2023 Flag_Non_Static_Expr
2024 ("non-static expression used for choice!", Choice);
2028 Elit := Expr_Value_E (Choice);
2030 if Present (Enumeration_Rep_Expr (Elit)) then
2031 Error_Msg_Sloc := Sloc (Enumeration_Rep_Expr (Elit));
2033 ("representation for& previously given#",
2038 Set_Enumeration_Rep_Expr (Elit, Choice);
2040 Expr := Expression (Assoc);
2041 Val := Static_Integer (Expr);
2043 if Val = No_Uint then
2046 elsif Val < Lo or else Hi < Val then
2047 Error_Msg_N ("value outside permitted range", Expr);
2051 Set_Enumeration_Rep (Elit, Val);
2060 -- Aggregate is fully processed. Now we check that a full set of
2061 -- representations was given, and that they are in range and in order.
2062 -- These checks are only done if no other errors occurred.
2068 Elit := First_Literal (Enumtype);
2069 while Present (Elit) loop
2070 if No (Enumeration_Rep_Expr (Elit)) then
2071 Error_Msg_NE ("missing representation for&!", N, Elit);
2074 Val := Enumeration_Rep (Elit);
2076 if Min = No_Uint then
2080 if Val /= No_Uint then
2081 if Max /= No_Uint and then Val <= Max then
2083 ("enumeration value for& not ordered!",
2084 Enumeration_Rep_Expr (Elit), Elit);
2090 -- If there is at least one literal whose representation
2091 -- is not equal to the Pos value, then note that this
2092 -- enumeration type has a non-standard representation.
2094 if Val /= Enumeration_Pos (Elit) then
2095 Set_Has_Non_Standard_Rep (Base_Type (Enumtype));
2102 -- Now set proper size information
2105 Minsize : Uint := UI_From_Int (Minimum_Size (Enumtype));
2108 if Has_Size_Clause (Enumtype) then
2109 if Esize (Enumtype) >= Minsize then
2114 UI_From_Int (Minimum_Size (Enumtype, Biased => True));
2116 if Esize (Enumtype) < Minsize then
2117 Error_Msg_N ("previously given size is too small", N);
2120 Set_Has_Biased_Representation (Enumtype);
2125 Set_RM_Size (Enumtype, Minsize);
2126 Set_Enum_Esize (Enumtype);
2129 Set_RM_Size (Base_Type (Enumtype), RM_Size (Enumtype));
2130 Set_Esize (Base_Type (Enumtype), Esize (Enumtype));
2131 Set_Alignment (Base_Type (Enumtype), Alignment (Enumtype));
2135 -- We repeat the too late test in case it froze itself!
2137 if Rep_Item_Too_Late (Enumtype, N) then
2140 end Analyze_Enumeration_Representation_Clause;
2142 ----------------------------
2143 -- Analyze_Free_Statement --
2144 ----------------------------
2146 procedure Analyze_Free_Statement (N : Node_Id) is
2148 Analyze (Expression (N));
2149 end Analyze_Free_Statement;
2151 ------------------------------------------
2152 -- Analyze_Record_Representation_Clause --
2153 ------------------------------------------
2155 procedure Analyze_Record_Representation_Clause (N : Node_Id) is
2156 Loc : constant Source_Ptr := Sloc (N);
2157 Ident : constant Node_Id := Identifier (N);
2158 Rectype : Entity_Id;
2164 Hbit : Uint := Uint_0;
2169 Max_Bit_So_Far : Uint;
2170 -- Records the maximum bit position so far. If all field positions
2171 -- are monotonically increasing, then we can skip the circuit for
2172 -- checking for overlap, since no overlap is possible.
2174 Overlap_Check_Required : Boolean;
2175 -- Used to keep track of whether or not an overlap check is required
2177 Ccount : Natural := 0;
2178 -- Number of component clauses in record rep clause
2180 CR_Pragma : Node_Id := Empty;
2181 -- Points to N_Pragma node if Complete_Representation pragma present
2184 if Ignore_Rep_Clauses then
2189 Rectype := Entity (Ident);
2191 if Rectype = Any_Type
2192 or else Rep_Item_Too_Early (Rectype, N)
2196 Rectype := Underlying_Type (Rectype);
2199 -- First some basic error checks
2201 if not Is_Record_Type (Rectype) then
2203 ("record type required, found}", Ident, First_Subtype (Rectype));
2206 elsif Is_Unchecked_Union (Rectype) then
2208 ("record rep clause not allowed for Unchecked_Union", N);
2210 elsif Scope (Rectype) /= Current_Scope then
2211 Error_Msg_N ("type must be declared in this scope", N);
2214 elsif not Is_First_Subtype (Rectype) then
2215 Error_Msg_N ("cannot give record rep clause for subtype", N);
2218 elsif Has_Record_Rep_Clause (Rectype) then
2219 Error_Msg_N ("duplicate record rep clause ignored", N);
2222 elsif Rep_Item_Too_Late (Rectype, N) then
2226 if Present (Mod_Clause (N)) then
2228 Loc : constant Source_Ptr := Sloc (N);
2229 M : constant Node_Id := Mod_Clause (N);
2230 P : constant List_Id := Pragmas_Before (M);
2234 pragma Warnings (Off, Mod_Val);
2237 Check_Restriction (No_Obsolescent_Features, Mod_Clause (N));
2239 if Warn_On_Obsolescent_Feature then
2241 ("mod clause is an obsolescent feature (RM J.8)?", N);
2243 ("\use alignment attribute definition clause instead?", N);
2250 -- In ASIS_Mode mode, expansion is disabled, but we must convert
2251 -- the Mod clause into an alignment clause anyway, so that the
2252 -- back-end can compute and back-annotate properly the size and
2253 -- alignment of types that may include this record.
2255 -- This seems dubious, this destroys the source tree in a manner
2256 -- not detectable by ASIS ???
2258 if Operating_Mode = Check_Semantics
2262 Make_Attribute_Definition_Clause (Loc,
2263 Name => New_Reference_To (Base_Type (Rectype), Loc),
2264 Chars => Name_Alignment,
2265 Expression => Relocate_Node (Expression (M)));
2267 Set_From_At_Mod (AtM_Nod);
2268 Insert_After (N, AtM_Nod);
2269 Mod_Val := Get_Alignment_Value (Expression (AtM_Nod));
2270 Set_Mod_Clause (N, Empty);
2273 -- Get the alignment value to perform error checking
2275 Mod_Val := Get_Alignment_Value (Expression (M));
2281 -- For untagged types, clear any existing component clauses for the
2282 -- type. If the type is derived, this is what allows us to override
2283 -- a rep clause for the parent. For type extensions, the representation
2284 -- of the inherited components is inherited, so we want to keep previous
2285 -- component clauses for completeness.
2287 if not Is_Tagged_Type (Rectype) then
2288 Comp := First_Component_Or_Discriminant (Rectype);
2289 while Present (Comp) loop
2290 Set_Component_Clause (Comp, Empty);
2291 Next_Component_Or_Discriminant (Comp);
2295 -- All done if no component clauses
2297 CC := First (Component_Clauses (N));
2303 -- If a tag is present, then create a component clause that places it
2304 -- at the start of the record (otherwise gigi may place it after other
2305 -- fields that have rep clauses).
2307 Fent := First_Entity (Rectype);
2309 if Nkind (Fent) = N_Defining_Identifier
2310 and then Chars (Fent) = Name_uTag
2312 Set_Component_Bit_Offset (Fent, Uint_0);
2313 Set_Normalized_Position (Fent, Uint_0);
2314 Set_Normalized_First_Bit (Fent, Uint_0);
2315 Set_Normalized_Position_Max (Fent, Uint_0);
2316 Init_Esize (Fent, System_Address_Size);
2318 Set_Component_Clause (Fent,
2319 Make_Component_Clause (Loc,
2321 Make_Identifier (Loc,
2322 Chars => Name_uTag),
2325 Make_Integer_Literal (Loc,
2329 Make_Integer_Literal (Loc,
2333 Make_Integer_Literal (Loc,
2334 UI_From_Int (System_Address_Size))));
2336 Ccount := Ccount + 1;
2339 -- A representation like this applies to the base type
2341 Set_Has_Record_Rep_Clause (Base_Type (Rectype));
2342 Set_Has_Non_Standard_Rep (Base_Type (Rectype));
2343 Set_Has_Specified_Layout (Base_Type (Rectype));
2345 Max_Bit_So_Far := Uint_Minus_1;
2346 Overlap_Check_Required := False;
2348 -- Process the component clauses
2350 while Present (CC) loop
2354 if Nkind (CC) = N_Pragma then
2357 -- The only pragma of interest is Complete_Representation
2359 if Pragma_Name (CC) = Name_Complete_Representation then
2363 -- Processing for real component clause
2366 Ccount := Ccount + 1;
2367 Posit := Static_Integer (Position (CC));
2368 Fbit := Static_Integer (First_Bit (CC));
2369 Lbit := Static_Integer (Last_Bit (CC));
2372 and then Fbit /= No_Uint
2373 and then Lbit /= No_Uint
2377 ("position cannot be negative", Position (CC));
2381 ("first bit cannot be negative", First_Bit (CC));
2383 -- The Last_Bit specified in a component clause must not be
2384 -- less than the First_Bit minus one (RM-13.5.1(10)).
2386 elsif Lbit < Fbit - 1 then
2388 ("last bit cannot be less than first bit minus one",
2391 -- Values look OK, so find the corresponding record component
2392 -- Even though the syntax allows an attribute reference for
2393 -- implementation-defined components, GNAT does not allow the
2394 -- tag to get an explicit position.
2396 elsif Nkind (Component_Name (CC)) = N_Attribute_Reference then
2397 if Attribute_Name (Component_Name (CC)) = Name_Tag then
2398 Error_Msg_N ("position of tag cannot be specified", CC);
2400 Error_Msg_N ("illegal component name", CC);
2404 Comp := First_Entity (Rectype);
2405 while Present (Comp) loop
2406 exit when Chars (Comp) = Chars (Component_Name (CC));
2412 -- Maybe component of base type that is absent from
2413 -- statically constrained first subtype.
2415 Comp := First_Entity (Base_Type (Rectype));
2416 while Present (Comp) loop
2417 exit when Chars (Comp) = Chars (Component_Name (CC));
2424 ("component clause is for non-existent field", CC);
2426 elsif Present (Component_Clause (Comp)) then
2428 -- Diagnose duplicate rep clause, or check consistency
2429 -- if this is an inherited component. In a double fault,
2430 -- there may be a duplicate inconsistent clause for an
2431 -- inherited component.
2433 if Scope (Original_Record_Component (Comp)) = Rectype
2434 or else Parent (Component_Clause (Comp)) = N
2436 Error_Msg_Sloc := Sloc (Component_Clause (Comp));
2437 Error_Msg_N ("component clause previously given#", CC);
2441 Rep1 : constant Node_Id := Component_Clause (Comp);
2443 if Intval (Position (Rep1)) /=
2444 Intval (Position (CC))
2445 or else Intval (First_Bit (Rep1)) /=
2446 Intval (First_Bit (CC))
2447 or else Intval (Last_Bit (Rep1)) /=
2448 Intval (Last_Bit (CC))
2450 Error_Msg_N ("component clause inconsistent "
2451 & "with representation of ancestor", CC);
2452 elsif Warn_On_Redundant_Constructs then
2453 Error_Msg_N ("?redundant component clause "
2454 & "for inherited component!", CC);
2460 -- Make reference for field in record rep clause and set
2461 -- appropriate entity field in the field identifier.
2464 (Comp, Component_Name (CC), Set_Ref => False);
2465 Set_Entity (Component_Name (CC), Comp);
2467 -- Update Fbit and Lbit to the actual bit number
2469 Fbit := Fbit + UI_From_Int (SSU) * Posit;
2470 Lbit := Lbit + UI_From_Int (SSU) * Posit;
2472 if Fbit <= Max_Bit_So_Far then
2473 Overlap_Check_Required := True;
2475 Max_Bit_So_Far := Lbit;
2478 if Has_Size_Clause (Rectype)
2479 and then Esize (Rectype) <= Lbit
2482 ("bit number out of range of specified size",
2485 Set_Component_Clause (Comp, CC);
2486 Set_Component_Bit_Offset (Comp, Fbit);
2487 Set_Esize (Comp, 1 + (Lbit - Fbit));
2488 Set_Normalized_First_Bit (Comp, Fbit mod SSU);
2489 Set_Normalized_Position (Comp, Fbit / SSU);
2491 Set_Normalized_Position_Max
2492 (Fent, Normalized_Position (Fent));
2494 if Is_Tagged_Type (Rectype)
2495 and then Fbit < System_Address_Size
2498 ("component overlaps tag field of&",
2502 -- This information is also set in the corresponding
2503 -- component of the base type, found by accessing the
2504 -- Original_Record_Component link if it is present.
2506 Ocomp := Original_Record_Component (Comp);
2513 (Component_Name (CC),
2518 Set_Has_Biased_Representation (Comp, Biased);
2520 if Biased and Warn_On_Biased_Representation then
2522 ("?component clause forces biased "
2523 & "representation", CC);
2526 if Present (Ocomp) then
2527 Set_Component_Clause (Ocomp, CC);
2528 Set_Component_Bit_Offset (Ocomp, Fbit);
2529 Set_Normalized_First_Bit (Ocomp, Fbit mod SSU);
2530 Set_Normalized_Position (Ocomp, Fbit / SSU);
2531 Set_Esize (Ocomp, 1 + (Lbit - Fbit));
2533 Set_Normalized_Position_Max
2534 (Ocomp, Normalized_Position (Ocomp));
2536 Set_Has_Biased_Representation
2537 (Ocomp, Has_Biased_Representation (Comp));
2540 if Esize (Comp) < 0 then
2541 Error_Msg_N ("component size is negative", CC);
2552 -- Now that we have processed all the component clauses, check for
2553 -- overlap. We have to leave this till last, since the components can
2554 -- appear in any arbitrary order in the representation clause.
2556 -- We do not need this check if all specified ranges were monotonic,
2557 -- as recorded by Overlap_Check_Required being False at this stage.
2559 -- This first section checks if there are any overlapping entries at
2560 -- all. It does this by sorting all entries and then seeing if there are
2561 -- any overlaps. If there are none, then that is decisive, but if there
2562 -- are overlaps, they may still be OK (they may result from fields in
2563 -- different variants).
2565 if Overlap_Check_Required then
2566 Overlap_Check1 : declare
2568 OC_Fbit : array (0 .. Ccount) of Uint;
2569 -- First-bit values for component clauses, the value is the offset
2570 -- of the first bit of the field from start of record. The zero
2571 -- entry is for use in sorting.
2573 OC_Lbit : array (0 .. Ccount) of Uint;
2574 -- Last-bit values for component clauses, the value is the offset
2575 -- of the last bit of the field from start of record. The zero
2576 -- entry is for use in sorting.
2578 OC_Count : Natural := 0;
2579 -- Count of entries in OC_Fbit and OC_Lbit
2581 function OC_Lt (Op1, Op2 : Natural) return Boolean;
2582 -- Compare routine for Sort
2584 procedure OC_Move (From : Natural; To : Natural);
2585 -- Move routine for Sort
2587 package Sorting is new GNAT.Heap_Sort_G (OC_Move, OC_Lt);
2589 function OC_Lt (Op1, Op2 : Natural) return Boolean is
2591 return OC_Fbit (Op1) < OC_Fbit (Op2);
2594 procedure OC_Move (From : Natural; To : Natural) is
2596 OC_Fbit (To) := OC_Fbit (From);
2597 OC_Lbit (To) := OC_Lbit (From);
2601 CC := First (Component_Clauses (N));
2602 while Present (CC) loop
2603 if Nkind (CC) /= N_Pragma then
2604 Posit := Static_Integer (Position (CC));
2605 Fbit := Static_Integer (First_Bit (CC));
2606 Lbit := Static_Integer (Last_Bit (CC));
2609 and then Fbit /= No_Uint
2610 and then Lbit /= No_Uint
2612 OC_Count := OC_Count + 1;
2613 Posit := Posit * SSU;
2614 OC_Fbit (OC_Count) := Fbit + Posit;
2615 OC_Lbit (OC_Count) := Lbit + Posit;
2622 Sorting.Sort (OC_Count);
2624 Overlap_Check_Required := False;
2625 for J in 1 .. OC_Count - 1 loop
2626 if OC_Lbit (J) >= OC_Fbit (J + 1) then
2627 Overlap_Check_Required := True;
2634 -- If Overlap_Check_Required is still True, then we have to do the full
2635 -- scale overlap check, since we have at least two fields that do
2636 -- overlap, and we need to know if that is OK since they are in
2637 -- different variant, or whether we have a definite problem.
2639 if Overlap_Check_Required then
2640 Overlap_Check2 : declare
2641 C1_Ent, C2_Ent : Entity_Id;
2642 -- Entities of components being checked for overlap
2645 -- Component_List node whose Component_Items are being checked
2648 -- Component declaration for component being checked
2651 C1_Ent := First_Entity (Base_Type (Rectype));
2653 -- Loop through all components in record. For each component check
2654 -- for overlap with any of the preceding elements on the component
2655 -- list containing the component and also, if the component is in
2656 -- a variant, check against components outside the case structure.
2657 -- This latter test is repeated recursively up the variant tree.
2659 Main_Component_Loop : while Present (C1_Ent) loop
2660 if Ekind (C1_Ent) /= E_Component
2661 and then Ekind (C1_Ent) /= E_Discriminant
2663 goto Continue_Main_Component_Loop;
2666 -- Skip overlap check if entity has no declaration node. This
2667 -- happens with discriminants in constrained derived types.
2668 -- Probably we are missing some checks as a result, but that
2669 -- does not seem terribly serious ???
2671 if No (Declaration_Node (C1_Ent)) then
2672 goto Continue_Main_Component_Loop;
2675 Clist := Parent (List_Containing (Declaration_Node (C1_Ent)));
2677 -- Loop through component lists that need checking. Check the
2678 -- current component list and all lists in variants above us.
2680 Component_List_Loop : loop
2682 -- If derived type definition, go to full declaration
2683 -- If at outer level, check discriminants if there are any.
2685 if Nkind (Clist) = N_Derived_Type_Definition then
2686 Clist := Parent (Clist);
2689 -- Outer level of record definition, check discriminants
2691 if Nkind_In (Clist, N_Full_Type_Declaration,
2692 N_Private_Type_Declaration)
2694 if Has_Discriminants (Defining_Identifier (Clist)) then
2696 First_Discriminant (Defining_Identifier (Clist));
2698 while Present (C2_Ent) loop
2699 exit when C1_Ent = C2_Ent;
2700 Check_Component_Overlap (C1_Ent, C2_Ent);
2701 Next_Discriminant (C2_Ent);
2705 -- Record extension case
2707 elsif Nkind (Clist) = N_Derived_Type_Definition then
2710 -- Otherwise check one component list
2713 Citem := First (Component_Items (Clist));
2715 while Present (Citem) loop
2716 if Nkind (Citem) = N_Component_Declaration then
2717 C2_Ent := Defining_Identifier (Citem);
2718 exit when C1_Ent = C2_Ent;
2719 Check_Component_Overlap (C1_Ent, C2_Ent);
2726 -- Check for variants above us (the parent of the Clist can
2727 -- be a variant, in which case its parent is a variant part,
2728 -- and the parent of the variant part is a component list
2729 -- whose components must all be checked against the current
2730 -- component for overlap).
2732 if Nkind (Parent (Clist)) = N_Variant then
2733 Clist := Parent (Parent (Parent (Clist)));
2735 -- Check for possible discriminant part in record, this is
2736 -- treated essentially as another level in the recursion.
2737 -- For this case the parent of the component list is the
2738 -- record definition, and its parent is the full type
2739 -- declaration containing the discriminant specifications.
2741 elsif Nkind (Parent (Clist)) = N_Record_Definition then
2742 Clist := Parent (Parent ((Clist)));
2744 -- If neither of these two cases, we are at the top of
2748 exit Component_List_Loop;
2750 end loop Component_List_Loop;
2752 <<Continue_Main_Component_Loop>>
2753 Next_Entity (C1_Ent);
2755 end loop Main_Component_Loop;
2759 -- For records that have component clauses for all components, and whose
2760 -- size is less than or equal to 32, we need to know the size in the
2761 -- front end to activate possible packed array processing where the
2762 -- component type is a record.
2764 -- At this stage Hbit + 1 represents the first unused bit from all the
2765 -- component clauses processed, so if the component clauses are
2766 -- complete, then this is the length of the record.
2768 -- For records longer than System.Storage_Unit, and for those where not
2769 -- all components have component clauses, the back end determines the
2770 -- length (it may for example be appropriate to round up the size
2771 -- to some convenient boundary, based on alignment considerations, etc).
2773 if Unknown_RM_Size (Rectype) and then Hbit + 1 <= 32 then
2775 -- Nothing to do if at least one component has no component clause
2777 Comp := First_Component_Or_Discriminant (Rectype);
2778 while Present (Comp) loop
2779 exit when No (Component_Clause (Comp));
2780 Next_Component_Or_Discriminant (Comp);
2783 -- If we fall out of loop, all components have component clauses
2784 -- and so we can set the size to the maximum value.
2787 Set_RM_Size (Rectype, Hbit + 1);
2791 -- Check missing components if Complete_Representation pragma appeared
2793 if Present (CR_Pragma) then
2794 Comp := First_Component_Or_Discriminant (Rectype);
2795 while Present (Comp) loop
2796 if No (Component_Clause (Comp)) then
2798 ("missing component clause for &", CR_Pragma, Comp);
2801 Next_Component_Or_Discriminant (Comp);
2804 -- If no Complete_Representation pragma, warn if missing components
2806 elsif Warn_On_Unrepped_Components then
2808 Num_Repped_Components : Nat := 0;
2809 Num_Unrepped_Components : Nat := 0;
2812 -- First count number of repped and unrepped components
2814 Comp := First_Component_Or_Discriminant (Rectype);
2815 while Present (Comp) loop
2816 if Present (Component_Clause (Comp)) then
2817 Num_Repped_Components := Num_Repped_Components + 1;
2819 Num_Unrepped_Components := Num_Unrepped_Components + 1;
2822 Next_Component_Or_Discriminant (Comp);
2825 -- We are only interested in the case where there is at least one
2826 -- unrepped component, and at least half the components have rep
2827 -- clauses. We figure that if less than half have them, then the
2828 -- partial rep clause is really intentional. If the component
2829 -- type has no underlying type set at this point (as for a generic
2830 -- formal type), we don't know enough to give a warning on the
2833 if Num_Unrepped_Components > 0
2834 and then Num_Unrepped_Components < Num_Repped_Components
2836 Comp := First_Component_Or_Discriminant (Rectype);
2837 while Present (Comp) loop
2838 if No (Component_Clause (Comp))
2839 and then Comes_From_Source (Comp)
2840 and then Present (Underlying_Type (Etype (Comp)))
2841 and then (Is_Scalar_Type (Underlying_Type (Etype (Comp)))
2842 or else Size_Known_At_Compile_Time
2843 (Underlying_Type (Etype (Comp))))
2844 and then not Has_Warnings_Off (Rectype)
2846 Error_Msg_Sloc := Sloc (Comp);
2848 ("?no component clause given for & declared #",
2852 Next_Component_Or_Discriminant (Comp);
2857 end Analyze_Record_Representation_Clause;
2859 -----------------------------
2860 -- Check_Component_Overlap --
2861 -----------------------------
2863 procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id) is
2865 if Present (Component_Clause (C1_Ent))
2866 and then Present (Component_Clause (C2_Ent))
2868 -- Exclude odd case where we have two tag fields in the same record,
2869 -- both at location zero. This seems a bit strange, but it seems to
2870 -- happen in some circumstances ???
2872 if Chars (C1_Ent) = Name_uTag
2873 and then Chars (C2_Ent) = Name_uTag
2878 -- Here we check if the two fields overlap
2881 S1 : constant Uint := Component_Bit_Offset (C1_Ent);
2882 S2 : constant Uint := Component_Bit_Offset (C2_Ent);
2883 E1 : constant Uint := S1 + Esize (C1_Ent);
2884 E2 : constant Uint := S2 + Esize (C2_Ent);
2887 if E2 <= S1 or else E1 <= S2 then
2891 Component_Name (Component_Clause (C2_Ent));
2892 Error_Msg_Sloc := Sloc (Error_Msg_Node_2);
2894 Component_Name (Component_Clause (C1_Ent));
2896 ("component& overlaps & #",
2897 Component_Name (Component_Clause (C1_Ent)));
2901 end Check_Component_Overlap;
2903 -----------------------------------
2904 -- Check_Constant_Address_Clause --
2905 -----------------------------------
2907 procedure Check_Constant_Address_Clause
2911 procedure Check_At_Constant_Address (Nod : Node_Id);
2912 -- Checks that the given node N represents a name whose 'Address is
2913 -- constant (in the same sense as OK_Constant_Address_Clause, i.e. the
2914 -- address value is the same at the point of declaration of U_Ent and at
2915 -- the time of elaboration of the address clause.
2917 procedure Check_Expr_Constants (Nod : Node_Id);
2918 -- Checks that Nod meets the requirements for a constant address clause
2919 -- in the sense of the enclosing procedure.
2921 procedure Check_List_Constants (Lst : List_Id);
2922 -- Check that all elements of list Lst meet the requirements for a
2923 -- constant address clause in the sense of the enclosing procedure.
2925 -------------------------------
2926 -- Check_At_Constant_Address --
2927 -------------------------------
2929 procedure Check_At_Constant_Address (Nod : Node_Id) is
2931 if Is_Entity_Name (Nod) then
2932 if Present (Address_Clause (Entity ((Nod)))) then
2934 ("invalid address clause for initialized object &!",
2937 ("address for& cannot" &
2938 " depend on another address clause! (RM 13.1(22))!",
2941 elsif In_Same_Source_Unit (Entity (Nod), U_Ent)
2942 and then Sloc (U_Ent) < Sloc (Entity (Nod))
2945 ("invalid address clause for initialized object &!",
2947 Error_Msg_Name_1 := Chars (Entity (Nod));
2948 Error_Msg_Name_2 := Chars (U_Ent);
2950 ("\% must be defined before % (RM 13.1(22))!",
2954 elsif Nkind (Nod) = N_Selected_Component then
2956 T : constant Entity_Id := Etype (Prefix (Nod));
2959 if (Is_Record_Type (T)
2960 and then Has_Discriminants (T))
2963 and then Is_Record_Type (Designated_Type (T))
2964 and then Has_Discriminants (Designated_Type (T)))
2967 ("invalid address clause for initialized object &!",
2970 ("\address cannot depend on component" &
2971 " of discriminated record (RM 13.1(22))!",
2974 Check_At_Constant_Address (Prefix (Nod));
2978 elsif Nkind (Nod) = N_Indexed_Component then
2979 Check_At_Constant_Address (Prefix (Nod));
2980 Check_List_Constants (Expressions (Nod));
2983 Check_Expr_Constants (Nod);
2985 end Check_At_Constant_Address;
2987 --------------------------
2988 -- Check_Expr_Constants --
2989 --------------------------
2991 procedure Check_Expr_Constants (Nod : Node_Id) is
2992 Loc_U_Ent : constant Source_Ptr := Sloc (U_Ent);
2993 Ent : Entity_Id := Empty;
2996 if Nkind (Nod) in N_Has_Etype
2997 and then Etype (Nod) = Any_Type
3003 when N_Empty | N_Error =>
3006 when N_Identifier | N_Expanded_Name =>
3007 Ent := Entity (Nod);
3009 -- We need to look at the original node if it is different
3010 -- from the node, since we may have rewritten things and
3011 -- substituted an identifier representing the rewrite.
3013 if Original_Node (Nod) /= Nod then
3014 Check_Expr_Constants (Original_Node (Nod));
3016 -- If the node is an object declaration without initial
3017 -- value, some code has been expanded, and the expression
3018 -- is not constant, even if the constituents might be
3019 -- acceptable, as in A'Address + offset.
3021 if Ekind (Ent) = E_Variable
3023 Nkind (Declaration_Node (Ent)) = N_Object_Declaration
3025 No (Expression (Declaration_Node (Ent)))
3028 ("invalid address clause for initialized object &!",
3031 -- If entity is constant, it may be the result of expanding
3032 -- a check. We must verify that its declaration appears
3033 -- before the object in question, else we also reject the
3036 elsif Ekind (Ent) = E_Constant
3037 and then In_Same_Source_Unit (Ent, U_Ent)
3038 and then Sloc (Ent) > Loc_U_Ent
3041 ("invalid address clause for initialized object &!",
3048 -- Otherwise look at the identifier and see if it is OK
3050 if Ekind (Ent) = E_Named_Integer
3052 Ekind (Ent) = E_Named_Real
3059 Ekind (Ent) = E_Constant
3061 Ekind (Ent) = E_In_Parameter
3063 -- This is the case where we must have Ent defined before
3064 -- U_Ent. Clearly if they are in different units this
3065 -- requirement is met since the unit containing Ent is
3066 -- already processed.
3068 if not In_Same_Source_Unit (Ent, U_Ent) then
3071 -- Otherwise location of Ent must be before the location
3072 -- of U_Ent, that's what prior defined means.
3074 elsif Sloc (Ent) < Loc_U_Ent then
3079 ("invalid address clause for initialized object &!",
3081 Error_Msg_Name_1 := Chars (Ent);
3082 Error_Msg_Name_2 := Chars (U_Ent);
3084 ("\% must be defined before % (RM 13.1(22))!",
3088 elsif Nkind (Original_Node (Nod)) = N_Function_Call then
3089 Check_Expr_Constants (Original_Node (Nod));
3093 ("invalid address clause for initialized object &!",
3096 if Comes_From_Source (Ent) then
3097 Error_Msg_Name_1 := Chars (Ent);
3099 ("\reference to variable% not allowed"
3100 & " (RM 13.1(22))!", Nod);
3103 ("non-static expression not allowed"
3104 & " (RM 13.1(22))!", Nod);
3108 when N_Integer_Literal =>
3110 -- If this is a rewritten unchecked conversion, in a system
3111 -- where Address is an integer type, always use the base type
3112 -- for a literal value. This is user-friendly and prevents
3113 -- order-of-elaboration issues with instances of unchecked
3116 if Nkind (Original_Node (Nod)) = N_Function_Call then
3117 Set_Etype (Nod, Base_Type (Etype (Nod)));
3120 when N_Real_Literal |
3122 N_Character_Literal =>
3126 Check_Expr_Constants (Low_Bound (Nod));
3127 Check_Expr_Constants (High_Bound (Nod));
3129 when N_Explicit_Dereference =>
3130 Check_Expr_Constants (Prefix (Nod));
3132 when N_Indexed_Component =>
3133 Check_Expr_Constants (Prefix (Nod));
3134 Check_List_Constants (Expressions (Nod));
3137 Check_Expr_Constants (Prefix (Nod));
3138 Check_Expr_Constants (Discrete_Range (Nod));
3140 when N_Selected_Component =>
3141 Check_Expr_Constants (Prefix (Nod));
3143 when N_Attribute_Reference =>
3144 if Attribute_Name (Nod) = Name_Address
3146 Attribute_Name (Nod) = Name_Access
3148 Attribute_Name (Nod) = Name_Unchecked_Access
3150 Attribute_Name (Nod) = Name_Unrestricted_Access
3152 Check_At_Constant_Address (Prefix (Nod));
3155 Check_Expr_Constants (Prefix (Nod));
3156 Check_List_Constants (Expressions (Nod));
3160 Check_List_Constants (Component_Associations (Nod));
3161 Check_List_Constants (Expressions (Nod));
3163 when N_Component_Association =>
3164 Check_Expr_Constants (Expression (Nod));
3166 when N_Extension_Aggregate =>
3167 Check_Expr_Constants (Ancestor_Part (Nod));
3168 Check_List_Constants (Component_Associations (Nod));
3169 Check_List_Constants (Expressions (Nod));
3174 when N_Binary_Op | N_And_Then | N_Or_Else | N_Membership_Test =>
3175 Check_Expr_Constants (Left_Opnd (Nod));
3176 Check_Expr_Constants (Right_Opnd (Nod));
3179 Check_Expr_Constants (Right_Opnd (Nod));
3181 when N_Type_Conversion |
3182 N_Qualified_Expression |
3184 Check_Expr_Constants (Expression (Nod));
3186 when N_Unchecked_Type_Conversion =>
3187 Check_Expr_Constants (Expression (Nod));
3189 -- If this is a rewritten unchecked conversion, subtypes in
3190 -- this node are those created within the instance. To avoid
3191 -- order of elaboration issues, replace them with their base
3192 -- types. Note that address clauses can cause order of
3193 -- elaboration problems because they are elaborated by the
3194 -- back-end at the point of definition, and may mention
3195 -- entities declared in between (as long as everything is
3196 -- static). It is user-friendly to allow unchecked conversions
3199 if Nkind (Original_Node (Nod)) = N_Function_Call then
3200 Set_Etype (Expression (Nod),
3201 Base_Type (Etype (Expression (Nod))));
3202 Set_Etype (Nod, Base_Type (Etype (Nod)));
3205 when N_Function_Call =>
3206 if not Is_Pure (Entity (Name (Nod))) then
3208 ("invalid address clause for initialized object &!",
3212 ("\function & is not pure (RM 13.1(22))!",
3213 Nod, Entity (Name (Nod)));
3216 Check_List_Constants (Parameter_Associations (Nod));
3219 when N_Parameter_Association =>
3220 Check_Expr_Constants (Explicit_Actual_Parameter (Nod));
3224 ("invalid address clause for initialized object &!",
3227 ("\must be constant defined before& (RM 13.1(22))!",
3230 end Check_Expr_Constants;
3232 --------------------------
3233 -- Check_List_Constants --
3234 --------------------------
3236 procedure Check_List_Constants (Lst : List_Id) is
3240 if Present (Lst) then
3241 Nod1 := First (Lst);
3242 while Present (Nod1) loop
3243 Check_Expr_Constants (Nod1);
3247 end Check_List_Constants;
3249 -- Start of processing for Check_Constant_Address_Clause
3252 Check_Expr_Constants (Expr);
3253 end Check_Constant_Address_Clause;
3259 procedure Check_Size
3263 Biased : out Boolean)
3265 UT : constant Entity_Id := Underlying_Type (T);
3271 -- Dismiss cases for generic types or types with previous errors
3274 or else UT = Any_Type
3275 or else Is_Generic_Type (UT)
3276 or else Is_Generic_Type (Root_Type (UT))
3280 -- Check case of bit packed array
3282 elsif Is_Array_Type (UT)
3283 and then Known_Static_Component_Size (UT)
3284 and then Is_Bit_Packed_Array (UT)
3292 Asiz := Component_Size (UT);
3293 Indx := First_Index (UT);
3295 Ityp := Etype (Indx);
3297 -- If non-static bound, then we are not in the business of
3298 -- trying to check the length, and indeed an error will be
3299 -- issued elsewhere, since sizes of non-static array types
3300 -- cannot be set implicitly or explicitly.
3302 if not Is_Static_Subtype (Ityp) then
3306 -- Otherwise accumulate next dimension
3308 Asiz := Asiz * (Expr_Value (Type_High_Bound (Ityp)) -
3309 Expr_Value (Type_Low_Bound (Ityp)) +
3313 exit when No (Indx);
3319 Error_Msg_Uint_1 := Asiz;
3321 ("size for& too small, minimum allowed is ^", N, T);
3322 Set_Esize (T, Asiz);
3323 Set_RM_Size (T, Asiz);
3327 -- All other composite types are ignored
3329 elsif Is_Composite_Type (UT) then
3332 -- For fixed-point types, don't check minimum if type is not frozen,
3333 -- since we don't know all the characteristics of the type that can
3334 -- affect the size (e.g. a specified small) till freeze time.
3336 elsif Is_Fixed_Point_Type (UT)
3337 and then not Is_Frozen (UT)
3341 -- Cases for which a minimum check is required
3344 -- Ignore if specified size is correct for the type
3346 if Known_Esize (UT) and then Siz = Esize (UT) then
3350 -- Otherwise get minimum size
3352 M := UI_From_Int (Minimum_Size (UT));
3356 -- Size is less than minimum size, but one possibility remains
3357 -- that we can manage with the new size if we bias the type.
3359 M := UI_From_Int (Minimum_Size (UT, Biased => True));
3362 Error_Msg_Uint_1 := M;
3364 ("size for& too small, minimum allowed is ^", N, T);
3374 -------------------------
3375 -- Get_Alignment_Value --
3376 -------------------------
3378 function Get_Alignment_Value (Expr : Node_Id) return Uint is
3379 Align : constant Uint := Static_Integer (Expr);
3382 if Align = No_Uint then
3385 elsif Align <= 0 then
3386 Error_Msg_N ("alignment value must be positive", Expr);
3390 for J in Int range 0 .. 64 loop
3392 M : constant Uint := Uint_2 ** J;
3395 exit when M = Align;
3399 ("alignment value must be power of 2", Expr);
3407 end Get_Alignment_Value;
3413 procedure Initialize is
3415 Unchecked_Conversions.Init;
3418 -------------------------
3419 -- Is_Operational_Item --
3420 -------------------------
3422 function Is_Operational_Item (N : Node_Id) return Boolean is
3424 if Nkind (N) /= N_Attribute_Definition_Clause then
3428 Id : constant Attribute_Id := Get_Attribute_Id (Chars (N));
3430 return Id = Attribute_Input
3431 or else Id = Attribute_Output
3432 or else Id = Attribute_Read
3433 or else Id = Attribute_Write
3434 or else Id = Attribute_External_Tag;
3437 end Is_Operational_Item;
3443 function Minimum_Size
3445 Biased : Boolean := False) return Nat
3447 Lo : Uint := No_Uint;
3448 Hi : Uint := No_Uint;
3449 LoR : Ureal := No_Ureal;
3450 HiR : Ureal := No_Ureal;
3451 LoSet : Boolean := False;
3452 HiSet : Boolean := False;
3456 R_Typ : constant Entity_Id := Root_Type (T);
3459 -- If bad type, return 0
3461 if T = Any_Type then
3464 -- For generic types, just return zero. There cannot be any legitimate
3465 -- need to know such a size, but this routine may be called with a
3466 -- generic type as part of normal processing.
3468 elsif Is_Generic_Type (R_Typ)
3469 or else R_Typ = Any_Type
3473 -- Access types. Normally an access type cannot have a size smaller
3474 -- than the size of System.Address. The exception is on VMS, where
3475 -- we have short and long addresses, and it is possible for an access
3476 -- type to have a short address size (and thus be less than the size
3477 -- of System.Address itself). We simply skip the check for VMS, and
3478 -- leave it to the back end to do the check.
3480 elsif Is_Access_Type (T) then
3481 if OpenVMS_On_Target then
3484 return System_Address_Size;
3487 -- Floating-point types
3489 elsif Is_Floating_Point_Type (T) then
3490 return UI_To_Int (Esize (R_Typ));
3494 elsif Is_Discrete_Type (T) then
3496 -- The following loop is looking for the nearest compile time known
3497 -- bounds following the ancestor subtype chain. The idea is to find
3498 -- the most restrictive known bounds information.
3502 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3507 if Compile_Time_Known_Value (Type_Low_Bound (Ancest)) then
3508 Lo := Expr_Rep_Value (Type_Low_Bound (Ancest));
3515 if Compile_Time_Known_Value (Type_High_Bound (Ancest)) then
3516 Hi := Expr_Rep_Value (Type_High_Bound (Ancest));
3522 Ancest := Ancestor_Subtype (Ancest);
3525 Ancest := Base_Type (T);
3527 if Is_Generic_Type (Ancest) then
3533 -- Fixed-point types. We can't simply use Expr_Value to get the
3534 -- Corresponding_Integer_Value values of the bounds, since these do not
3535 -- get set till the type is frozen, and this routine can be called
3536 -- before the type is frozen. Similarly the test for bounds being static
3537 -- needs to include the case where we have unanalyzed real literals for
3540 elsif Is_Fixed_Point_Type (T) then
3542 -- The following loop is looking for the nearest compile time known
3543 -- bounds following the ancestor subtype chain. The idea is to find
3544 -- the most restrictive known bounds information.
3548 if Ancest = Any_Type or else Etype (Ancest) = Any_Type then
3552 -- Note: In the following two tests for LoSet and HiSet, it may
3553 -- seem redundant to test for N_Real_Literal here since normally
3554 -- one would assume that the test for the value being known at
3555 -- compile time includes this case. However, there is a glitch.
3556 -- If the real literal comes from folding a non-static expression,
3557 -- then we don't consider any non- static expression to be known
3558 -- at compile time if we are in configurable run time mode (needed
3559 -- in some cases to give a clearer definition of what is and what
3560 -- is not accepted). So the test is indeed needed. Without it, we
3561 -- would set neither Lo_Set nor Hi_Set and get an infinite loop.
3564 if Nkind (Type_Low_Bound (Ancest)) = N_Real_Literal
3565 or else Compile_Time_Known_Value (Type_Low_Bound (Ancest))
3567 LoR := Expr_Value_R (Type_Low_Bound (Ancest));
3574 if Nkind (Type_High_Bound (Ancest)) = N_Real_Literal
3575 or else Compile_Time_Known_Value (Type_High_Bound (Ancest))
3577 HiR := Expr_Value_R (Type_High_Bound (Ancest));
3583 Ancest := Ancestor_Subtype (Ancest);
3586 Ancest := Base_Type (T);
3588 if Is_Generic_Type (Ancest) then
3594 Lo := UR_To_Uint (LoR / Small_Value (T));
3595 Hi := UR_To_Uint (HiR / Small_Value (T));
3597 -- No other types allowed
3600 raise Program_Error;
3603 -- Fall through with Hi and Lo set. Deal with biased case
3606 and then not Is_Fixed_Point_Type (T)
3607 and then not (Is_Enumeration_Type (T)
3608 and then Has_Non_Standard_Rep (T)))
3609 or else Has_Biased_Representation (T)
3615 -- Signed case. Note that we consider types like range 1 .. -1 to be
3616 -- signed for the purpose of computing the size, since the bounds have
3617 -- to be accommodated in the base type.
3619 if Lo < 0 or else Hi < 0 then
3623 -- S = size, B = 2 ** (size - 1) (can accommodate -B .. +(B - 1))
3624 -- Note that we accommodate the case where the bounds cross. This
3625 -- can happen either because of the way the bounds are declared
3626 -- or because of the algorithm in Freeze_Fixed_Point_Type.
3640 -- If both bounds are positive, make sure that both are represen-
3641 -- table in the case where the bounds are crossed. This can happen
3642 -- either because of the way the bounds are declared, or because of
3643 -- the algorithm in Freeze_Fixed_Point_Type.
3649 -- S = size, (can accommodate 0 .. (2**size - 1))
3652 while Hi >= Uint_2 ** S loop
3660 ---------------------------
3661 -- New_Stream_Subprogram --
3662 ---------------------------
3664 procedure New_Stream_Subprogram
3668 Nam : TSS_Name_Type)
3670 Loc : constant Source_Ptr := Sloc (N);
3671 Sname : constant Name_Id := Make_TSS_Name (Base_Type (Ent), Nam);
3672 Subp_Id : Entity_Id;
3673 Subp_Decl : Node_Id;
3677 Defer_Declaration : constant Boolean :=
3678 Is_Tagged_Type (Ent) or else Is_Private_Type (Ent);
3679 -- For a tagged type, there is a declaration for each stream attribute
3680 -- at the freeze point, and we must generate only a completion of this
3681 -- declaration. We do the same for private types, because the full view
3682 -- might be tagged. Otherwise we generate a declaration at the point of
3683 -- the attribute definition clause.
3685 function Build_Spec return Node_Id;
3686 -- Used for declaration and renaming declaration, so that this is
3687 -- treated as a renaming_as_body.
3693 function Build_Spec return Node_Id is
3694 Out_P : constant Boolean := (Nam = TSS_Stream_Read);
3697 T_Ref : constant Node_Id := New_Reference_To (Etyp, Loc);
3700 Subp_Id := Make_Defining_Identifier (Loc, Sname);
3702 -- S : access Root_Stream_Type'Class
3704 Formals := New_List (
3705 Make_Parameter_Specification (Loc,
3706 Defining_Identifier =>
3707 Make_Defining_Identifier (Loc, Name_S),
3709 Make_Access_Definition (Loc,
3712 Designated_Type (Etype (F)), Loc))));
3714 if Nam = TSS_Stream_Input then
3715 Spec := Make_Function_Specification (Loc,
3716 Defining_Unit_Name => Subp_Id,
3717 Parameter_Specifications => Formals,
3718 Result_Definition => T_Ref);
3723 Make_Parameter_Specification (Loc,
3724 Defining_Identifier => Make_Defining_Identifier (Loc, Name_V),
3725 Out_Present => Out_P,
3726 Parameter_Type => T_Ref));
3728 Spec := Make_Procedure_Specification (Loc,
3729 Defining_Unit_Name => Subp_Id,
3730 Parameter_Specifications => Formals);
3736 -- Start of processing for New_Stream_Subprogram
3739 F := First_Formal (Subp);
3741 if Ekind (Subp) = E_Procedure then
3742 Etyp := Etype (Next_Formal (F));
3744 Etyp := Etype (Subp);
3747 -- Prepare subprogram declaration and insert it as an action on the
3748 -- clause node. The visibility for this entity is used to test for
3749 -- visibility of the attribute definition clause (in the sense of
3750 -- 8.3(23) as amended by AI-195).
3752 if not Defer_Declaration then
3754 Make_Subprogram_Declaration (Loc,
3755 Specification => Build_Spec);
3757 -- For a tagged type, there is always a visible declaration for each
3758 -- stream TSS (it is a predefined primitive operation), and the
3759 -- completion of this declaration occurs at the freeze point, which is
3760 -- not always visible at places where the attribute definition clause is
3761 -- visible. So, we create a dummy entity here for the purpose of
3762 -- tracking the visibility of the attribute definition clause itself.
3766 Make_Defining_Identifier (Loc,
3767 Chars => New_External_Name (Sname, 'V'));
3769 Make_Object_Declaration (Loc,
3770 Defining_Identifier => Subp_Id,
3771 Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc));
3774 Insert_Action (N, Subp_Decl);
3775 Set_Entity (N, Subp_Id);
3778 Make_Subprogram_Renaming_Declaration (Loc,
3779 Specification => Build_Spec,
3780 Name => New_Reference_To (Subp, Loc));
3782 if Defer_Declaration then
3783 Set_TSS (Base_Type (Ent), Subp_Id);
3785 Insert_Action (N, Subp_Decl);
3786 Copy_TSS (Subp_Id, Base_Type (Ent));
3788 end New_Stream_Subprogram;
3790 ------------------------
3791 -- Rep_Item_Too_Early --
3792 ------------------------
3794 function Rep_Item_Too_Early (T : Entity_Id; N : Node_Id) return Boolean is
3796 -- Cannot apply non-operational rep items to generic types
3798 if Is_Operational_Item (N) then
3802 and then Is_Generic_Type (Root_Type (T))
3805 ("representation item not allowed for generic type", N);
3809 -- Otherwise check for incomplete type
3811 if Is_Incomplete_Or_Private_Type (T)
3812 and then No (Underlying_Type (T))
3815 ("representation item must be after full type declaration", N);
3818 -- If the type has incomplete components, a representation clause is
3819 -- illegal but stream attributes and Convention pragmas are correct.
3821 elsif Has_Private_Component (T) then
3822 if Nkind (N) = N_Pragma then
3826 ("representation item must appear after type is fully defined",
3833 end Rep_Item_Too_Early;
3835 -----------------------
3836 -- Rep_Item_Too_Late --
3837 -----------------------
3839 function Rep_Item_Too_Late
3842 FOnly : Boolean := False) return Boolean
3845 Parent_Type : Entity_Id;
3848 -- Output the too late message. Note that this is not considered a
3849 -- serious error, since the effect is simply that we ignore the
3850 -- representation clause in this case.
3856 procedure Too_Late is
3858 Error_Msg_N ("|representation item appears too late!", N);
3861 -- Start of processing for Rep_Item_Too_Late
3864 -- First make sure entity is not frozen (RM 13.1(9)). Exclude imported
3865 -- types, which may be frozen if they appear in a representation clause
3866 -- for a local type.
3869 and then not From_With_Type (T)
3872 S := First_Subtype (T);
3874 if Present (Freeze_Node (S)) then
3876 ("?no more representation items for }", Freeze_Node (S), S);
3881 -- Check for case of non-tagged derived type whose parent either has
3882 -- primitive operations, or is a by reference type (RM 13.1(10)).
3886 and then Is_Derived_Type (T)
3887 and then not Is_Tagged_Type (T)
3889 Parent_Type := Etype (Base_Type (T));
3891 if Has_Primitive_Operations (Parent_Type) then
3894 ("primitive operations already defined for&!", N, Parent_Type);
3897 elsif Is_By_Reference_Type (Parent_Type) then
3900 ("parent type & is a by reference type!", N, Parent_Type);
3905 -- No error, link item into head of chain of rep items for the entity,
3906 -- but avoid chaining if we have an overloadable entity, and the pragma
3907 -- is one that can apply to multiple overloaded entities.
3909 if Is_Overloadable (T)
3910 and then Nkind (N) = N_Pragma
3913 Pname : constant Name_Id := Pragma_Name (N);
3915 if Pname = Name_Convention or else
3916 Pname = Name_Import or else
3917 Pname = Name_Export or else
3918 Pname = Name_External or else
3919 Pname = Name_Interface
3926 Record_Rep_Item (T, N);
3928 end Rep_Item_Too_Late;
3930 -------------------------
3931 -- Same_Representation --
3932 -------------------------
3934 function Same_Representation (Typ1, Typ2 : Entity_Id) return Boolean is
3935 T1 : constant Entity_Id := Underlying_Type (Typ1);
3936 T2 : constant Entity_Id := Underlying_Type (Typ2);
3939 -- A quick check, if base types are the same, then we definitely have
3940 -- the same representation, because the subtype specific representation
3941 -- attributes (Size and Alignment) do not affect representation from
3942 -- the point of view of this test.
3944 if Base_Type (T1) = Base_Type (T2) then
3947 elsif Is_Private_Type (Base_Type (T2))
3948 and then Base_Type (T1) = Full_View (Base_Type (T2))
3953 -- Tagged types never have differing representations
3955 if Is_Tagged_Type (T1) then
3959 -- Representations are definitely different if conventions differ
3961 if Convention (T1) /= Convention (T2) then
3965 -- Representations are different if component alignments differ
3967 if (Is_Record_Type (T1) or else Is_Array_Type (T1))
3969 (Is_Record_Type (T2) or else Is_Array_Type (T2))
3970 and then Component_Alignment (T1) /= Component_Alignment (T2)
3975 -- For arrays, the only real issue is component size. If we know the
3976 -- component size for both arrays, and it is the same, then that's
3977 -- good enough to know we don't have a change of representation.
3979 if Is_Array_Type (T1) then
3980 if Known_Component_Size (T1)
3981 and then Known_Component_Size (T2)
3982 and then Component_Size (T1) = Component_Size (T2)
3988 -- Types definitely have same representation if neither has non-standard
3989 -- representation since default representations are always consistent.
3990 -- If only one has non-standard representation, and the other does not,
3991 -- then we consider that they do not have the same representation. They
3992 -- might, but there is no way of telling early enough.
3994 if Has_Non_Standard_Rep (T1) then
3995 if not Has_Non_Standard_Rep (T2) then
3999 return not Has_Non_Standard_Rep (T2);
4002 -- Here the two types both have non-standard representation, and we need
4003 -- to determine if they have the same non-standard representation.
4005 -- For arrays, we simply need to test if the component sizes are the
4006 -- same. Pragma Pack is reflected in modified component sizes, so this
4007 -- check also deals with pragma Pack.
4009 if Is_Array_Type (T1) then
4010 return Component_Size (T1) = Component_Size (T2);
4012 -- Tagged types always have the same representation, because it is not
4013 -- possible to specify different representations for common fields.
4015 elsif Is_Tagged_Type (T1) then
4018 -- Case of record types
4020 elsif Is_Record_Type (T1) then
4022 -- Packed status must conform
4024 if Is_Packed (T1) /= Is_Packed (T2) then
4027 -- Otherwise we must check components. Typ2 maybe a constrained
4028 -- subtype with fewer components, so we compare the components
4029 -- of the base types.
4032 Record_Case : declare
4033 CD1, CD2 : Entity_Id;
4035 function Same_Rep return Boolean;
4036 -- CD1 and CD2 are either components or discriminants. This
4037 -- function tests whether the two have the same representation
4043 function Same_Rep return Boolean is
4045 if No (Component_Clause (CD1)) then
4046 return No (Component_Clause (CD2));
4050 Present (Component_Clause (CD2))
4052 Component_Bit_Offset (CD1) = Component_Bit_Offset (CD2)
4054 Esize (CD1) = Esize (CD2);
4058 -- Start of processing for Record_Case
4061 if Has_Discriminants (T1) then
4062 CD1 := First_Discriminant (T1);
4063 CD2 := First_Discriminant (T2);
4065 -- The number of discriminants may be different if the
4066 -- derived type has fewer (constrained by values). The
4067 -- invisible discriminants retain the representation of
4068 -- the original, so the discrepancy does not per se
4069 -- indicate a different representation.
4072 and then Present (CD2)
4074 if not Same_Rep then
4077 Next_Discriminant (CD1);
4078 Next_Discriminant (CD2);
4083 CD1 := First_Component (Underlying_Type (Base_Type (T1)));
4084 CD2 := First_Component (Underlying_Type (Base_Type (T2)));
4086 while Present (CD1) loop
4087 if not Same_Rep then
4090 Next_Component (CD1);
4091 Next_Component (CD2);
4099 -- For enumeration types, we must check each literal to see if the
4100 -- representation is the same. Note that we do not permit enumeration
4101 -- representation clauses for Character and Wide_Character, so these
4102 -- cases were already dealt with.
4104 elsif Is_Enumeration_Type (T1) then
4106 Enumeration_Case : declare
4110 L1 := First_Literal (T1);
4111 L2 := First_Literal (T2);
4113 while Present (L1) loop
4114 if Enumeration_Rep (L1) /= Enumeration_Rep (L2) then
4124 end Enumeration_Case;
4126 -- Any other types have the same representation for these purposes
4131 end Same_Representation;
4133 --------------------
4134 -- Set_Enum_Esize --
4135 --------------------
4137 procedure Set_Enum_Esize (T : Entity_Id) is
4145 -- Find the minimum standard size (8,16,32,64) that fits
4147 Lo := Enumeration_Rep (Entity (Type_Low_Bound (T)));
4148 Hi := Enumeration_Rep (Entity (Type_High_Bound (T)));
4151 if Lo >= -Uint_2**07 and then Hi < Uint_2**07 then
4152 Sz := Standard_Character_Size; -- May be > 8 on some targets
4154 elsif Lo >= -Uint_2**15 and then Hi < Uint_2**15 then
4157 elsif Lo >= -Uint_2**31 and then Hi < Uint_2**31 then
4160 else pragma Assert (Lo >= -Uint_2**63 and then Hi < Uint_2**63);
4165 if Hi < Uint_2**08 then
4166 Sz := Standard_Character_Size; -- May be > 8 on some targets
4168 elsif Hi < Uint_2**16 then
4171 elsif Hi < Uint_2**32 then
4174 else pragma Assert (Hi < Uint_2**63);
4179 -- That minimum is the proper size unless we have a foreign convention
4180 -- and the size required is 32 or less, in which case we bump the size
4181 -- up to 32. This is required for C and C++ and seems reasonable for
4182 -- all other foreign conventions.
4184 if Has_Foreign_Convention (T)
4185 and then Esize (T) < Standard_Integer_Size
4187 Init_Esize (T, Standard_Integer_Size);
4193 ------------------------------
4194 -- Validate_Address_Clauses --
4195 ------------------------------
4197 procedure Validate_Address_Clauses is
4199 for J in Address_Clause_Checks.First .. Address_Clause_Checks.Last loop
4201 ACCR : Address_Clause_Check_Record
4202 renames Address_Clause_Checks.Table (J);
4211 -- Skip processing of this entry if warning already posted
4213 if not Address_Warning_Posted (ACCR.N) then
4215 -- Get alignments. Really we should always have the alignment
4216 -- of the objects properly back annotated, but right now the
4217 -- back end fails to back annotate for address clauses???
4219 if Known_Alignment (ACCR.X) then
4220 X_Alignment := Alignment (ACCR.X);
4222 X_Alignment := Alignment (Etype (ACCR.X));
4225 if Known_Alignment (ACCR.Y) then
4226 Y_Alignment := Alignment (ACCR.Y);
4228 Y_Alignment := Alignment (Etype (ACCR.Y));
4231 -- Similarly obtain sizes
4233 if Known_Esize (ACCR.X) then
4234 X_Size := Esize (ACCR.X);
4236 X_Size := Esize (Etype (ACCR.X));
4239 if Known_Esize (ACCR.Y) then
4240 Y_Size := Esize (ACCR.Y);
4242 Y_Size := Esize (Etype (ACCR.Y));
4245 -- Check for large object overlaying smaller one
4248 and then X_Size > Uint_0
4249 and then X_Size > Y_Size
4252 ("?size for overlaid object is too small", ACCR.N);
4253 Error_Msg_Uint_1 := X_Size;
4255 ("\?size of & is ^", ACCR.N, ACCR.X);
4256 Error_Msg_Uint_1 := Y_Size;
4258 ("\?size of & is ^", ACCR.N, ACCR.Y);
4260 -- Check for inadequate alignment. Again the defensive check
4261 -- on Y_Alignment should not be needed, but because of the
4262 -- failure in back end annotation, we can have an alignment
4265 -- Note: we do not check alignments if we gave a size
4266 -- warning, since it would likely be redundant.
4268 elsif Y_Alignment /= Uint_0
4269 and then Y_Alignment < X_Alignment
4272 ("?specified address for& may be inconsistent "
4276 ("\?program execution may be erroneous (RM 13.3(27))",
4278 Error_Msg_Uint_1 := X_Alignment;
4280 ("\?alignment of & is ^",
4282 Error_Msg_Uint_1 := Y_Alignment;
4284 ("\?alignment of & is ^",
4290 end Validate_Address_Clauses;
4292 -----------------------------------
4293 -- Validate_Unchecked_Conversion --
4294 -----------------------------------
4296 procedure Validate_Unchecked_Conversion
4298 Act_Unit : Entity_Id)
4305 -- Obtain source and target types. Note that we call Ancestor_Subtype
4306 -- here because the processing for generic instantiation always makes
4307 -- subtypes, and we want the original frozen actual types.
4309 -- If we are dealing with private types, then do the check on their
4310 -- fully declared counterparts if the full declarations have been
4311 -- encountered (they don't have to be visible, but they must exist!)
4313 Source := Ancestor_Subtype (Etype (First_Formal (Act_Unit)));
4315 if Is_Private_Type (Source)
4316 and then Present (Underlying_Type (Source))
4318 Source := Underlying_Type (Source);
4321 Target := Ancestor_Subtype (Etype (Act_Unit));
4323 -- If either type is generic, the instantiation happens within a generic
4324 -- unit, and there is nothing to check. The proper check
4325 -- will happen when the enclosing generic is instantiated.
4327 if Is_Generic_Type (Source) or else Is_Generic_Type (Target) then
4331 if Is_Private_Type (Target)
4332 and then Present (Underlying_Type (Target))
4334 Target := Underlying_Type (Target);
4337 -- Source may be unconstrained array, but not target
4339 if Is_Array_Type (Target)
4340 and then not Is_Constrained (Target)
4343 ("unchecked conversion to unconstrained array not allowed", N);
4347 -- Warn if conversion between two different convention pointers
4349 if Is_Access_Type (Target)
4350 and then Is_Access_Type (Source)
4351 and then Convention (Target) /= Convention (Source)
4352 and then Warn_On_Unchecked_Conversion
4354 -- Give warnings for subprogram pointers only on most targets. The
4355 -- exception is VMS, where data pointers can have different lengths
4356 -- depending on the pointer convention.
4358 if Is_Access_Subprogram_Type (Target)
4359 or else Is_Access_Subprogram_Type (Source)
4360 or else OpenVMS_On_Target
4363 ("?conversion between pointers with different conventions!", N);
4367 -- Warn if one of the operands is Ada.Calendar.Time. Do not emit a
4368 -- warning when compiling GNAT-related sources.
4370 if Warn_On_Unchecked_Conversion
4371 and then not In_Predefined_Unit (N)
4372 and then RTU_Loaded (Ada_Calendar)
4374 (Chars (Source) = Name_Time
4376 Chars (Target) = Name_Time)
4378 -- If Ada.Calendar is loaded and the name of one of the operands is
4379 -- Time, there is a good chance that this is Ada.Calendar.Time.
4382 Calendar_Time : constant Entity_Id :=
4383 Full_View (RTE (RO_CA_Time));
4385 pragma Assert (Present (Calendar_Time));
4387 if Source = Calendar_Time
4388 or else Target = Calendar_Time
4391 ("?representation of 'Time values may change between " &
4392 "'G'N'A'T versions", N);
4397 -- Make entry in unchecked conversion table for later processing by
4398 -- Validate_Unchecked_Conversions, which will check sizes and alignments
4399 -- (using values set by the back-end where possible). This is only done
4400 -- if the appropriate warning is active.
4402 if Warn_On_Unchecked_Conversion then
4403 Unchecked_Conversions.Append
4404 (New_Val => UC_Entry'
4409 -- If both sizes are known statically now, then back end annotation
4410 -- is not required to do a proper check but if either size is not
4411 -- known statically, then we need the annotation.
4413 if Known_Static_RM_Size (Source)
4414 and then Known_Static_RM_Size (Target)
4418 Back_Annotate_Rep_Info := True;
4422 -- If unchecked conversion to access type, and access type is declared
4423 -- in the same unit as the unchecked conversion, then set the
4424 -- No_Strict_Aliasing flag (no strict aliasing is implicit in this
4427 if Is_Access_Type (Target) and then
4428 In_Same_Source_Unit (Target, N)
4430 Set_No_Strict_Aliasing (Implementation_Base_Type (Target));
4433 -- Generate N_Validate_Unchecked_Conversion node for back end in
4434 -- case the back end needs to perform special validation checks.
4436 -- Shouldn't this be in Exp_Ch13, since the check only gets done
4437 -- if we have full expansion and the back end is called ???
4440 Make_Validate_Unchecked_Conversion (Sloc (N));
4441 Set_Source_Type (Vnode, Source);
4442 Set_Target_Type (Vnode, Target);
4444 -- If the unchecked conversion node is in a list, just insert before it.
4445 -- If not we have some strange case, not worth bothering about.
4447 if Is_List_Member (N) then
4448 Insert_After (N, Vnode);
4450 end Validate_Unchecked_Conversion;
4452 ------------------------------------
4453 -- Validate_Unchecked_Conversions --
4454 ------------------------------------
4456 procedure Validate_Unchecked_Conversions is
4458 for N in Unchecked_Conversions.First .. Unchecked_Conversions.Last loop
4460 T : UC_Entry renames Unchecked_Conversions.Table (N);
4462 Eloc : constant Source_Ptr := T.Eloc;
4463 Source : constant Entity_Id := T.Source;
4464 Target : constant Entity_Id := T.Target;
4470 -- This validation check, which warns if we have unequal sizes for
4471 -- unchecked conversion, and thus potentially implementation
4472 -- dependent semantics, is one of the few occasions on which we
4473 -- use the official RM size instead of Esize. See description in
4474 -- Einfo "Handling of Type'Size Values" for details.
4476 if Serious_Errors_Detected = 0
4477 and then Known_Static_RM_Size (Source)
4478 and then Known_Static_RM_Size (Target)
4480 Source_Siz := RM_Size (Source);
4481 Target_Siz := RM_Size (Target);
4483 if Source_Siz /= Target_Siz then
4485 ("?types for unchecked conversion have different sizes!",
4488 if All_Errors_Mode then
4489 Error_Msg_Name_1 := Chars (Source);
4490 Error_Msg_Uint_1 := Source_Siz;
4491 Error_Msg_Name_2 := Chars (Target);
4492 Error_Msg_Uint_2 := Target_Siz;
4493 Error_Msg ("\size of % is ^, size of % is ^?", Eloc);
4495 Error_Msg_Uint_1 := UI_Abs (Source_Siz - Target_Siz);
4497 if Is_Discrete_Type (Source)
4498 and then Is_Discrete_Type (Target)
4500 if Source_Siz > Target_Siz then
4502 ("\?^ high order bits of source will be ignored!",
4505 elsif Is_Unsigned_Type (Source) then
4507 ("\?source will be extended with ^ high order " &
4508 "zero bits?!", Eloc);
4512 ("\?source will be extended with ^ high order " &
4517 elsif Source_Siz < Target_Siz then
4518 if Is_Discrete_Type (Target) then
4519 if Bytes_Big_Endian then
4521 ("\?target value will include ^ undefined " &
4526 ("\?target value will include ^ undefined " &
4533 ("\?^ trailing bits of target value will be " &
4534 "undefined!", Eloc);
4537 else pragma Assert (Source_Siz > Target_Siz);
4539 ("\?^ trailing bits of source will be ignored!",
4546 -- If both types are access types, we need to check the alignment.
4547 -- If the alignment of both is specified, we can do it here.
4549 if Serious_Errors_Detected = 0
4550 and then Ekind (Source) in Access_Kind
4551 and then Ekind (Target) in Access_Kind
4552 and then Target_Strict_Alignment
4553 and then Present (Designated_Type (Source))
4554 and then Present (Designated_Type (Target))
4557 D_Source : constant Entity_Id := Designated_Type (Source);
4558 D_Target : constant Entity_Id := Designated_Type (Target);
4561 if Known_Alignment (D_Source)
4562 and then Known_Alignment (D_Target)
4565 Source_Align : constant Uint := Alignment (D_Source);
4566 Target_Align : constant Uint := Alignment (D_Target);
4569 if Source_Align < Target_Align
4570 and then not Is_Tagged_Type (D_Source)
4572 Error_Msg_Uint_1 := Target_Align;
4573 Error_Msg_Uint_2 := Source_Align;
4574 Error_Msg_Node_1 := D_Target;
4575 Error_Msg_Node_2 := D_Source;
4577 ("?alignment of & (^) is stricter than " &
4578 "alignment of & (^)!", Eloc);
4580 if All_Errors_Mode then
4582 ("\?resulting access value may have invalid " &
4583 "alignment!", Eloc);
4592 end Validate_Unchecked_Conversions;