1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1997-2010, 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 Einfo; use Einfo;
28 with Errout; use Errout;
30 with Namet; use Namet;
31 with Nlists; use Nlists;
34 with Sem_Aux; use Sem_Aux;
35 with Sem_Prag; use Sem_Prag;
36 with Sem_Util; use Sem_Util;
37 with Sinput; use Sinput;
38 with Sinfo; use Sinfo;
39 with Snames; use Snames;
40 with Stand; use Stand;
41 with Stringt; use Stringt;
44 with GNAT.HTable; use GNAT.HTable;
46 package body Sem_Elim is
48 No_Elimination : Boolean;
49 -- Set True if no Eliminate pragmas active
55 -- A single pragma Eliminate is represented by the following record
58 type Access_Elim_Data is access Elim_Data;
60 type Names is array (Nat range <>) of Name_Id;
61 -- Type used to represent set of names. Used for names in Unit_Name
62 -- and also the set of names in Argument_Types.
64 type Access_Names is access Names;
66 type Elim_Data is record
68 Unit_Name : Access_Names;
69 -- Unit name, broken down into a set of names (e.g. A.B.C is
70 -- represented as Name_Id values for A, B, C in sequence).
72 Entity_Name : Name_Id;
73 -- Entity name if Entity parameter if present. If no Entity parameter
74 -- was supplied, then Entity_Node is set to Empty, and the Entity_Name
75 -- field contains the last identifier name in the Unit_Name.
77 Entity_Scope : Access_Names;
78 -- Static scope of the entity within the compilation unit represented by
81 Entity_Node : Node_Id;
82 -- Save node of entity argument, for posting error messages. Set
83 -- to Empty if there is no entity argument.
85 Parameter_Types : Access_Names;
86 -- Set to set of names given for parameter types. If no parameter
87 -- types argument is present, this argument is set to null.
89 Result_Type : Name_Id;
90 -- Result type name if Result_Types parameter present, No_Name if not
92 Source_Location : Name_Id;
93 -- String describing the source location of subprogram defining name if
94 -- Source_Location parameter present, No_Name if not
96 Hash_Link : Access_Elim_Data;
97 -- Link for hash table use
99 Homonym : Access_Elim_Data;
100 -- Pointer to next entry with same key
103 -- Node_Id for Eliminate pragma
111 -- Setup hash table using the Entity_Name field as the hash key
113 subtype Element is Elim_Data;
114 subtype Elmt_Ptr is Access_Elim_Data;
116 subtype Key is Name_Id;
118 type Header_Num is range 0 .. 1023;
120 Null_Ptr : constant Elmt_Ptr := null;
122 ----------------------
123 -- Hash_Subprograms --
124 ----------------------
126 package Hash_Subprograms is
128 function Equal (F1, F2 : Key) return Boolean;
129 pragma Inline (Equal);
131 function Get_Key (E : Elmt_Ptr) return Key;
132 pragma Inline (Get_Key);
134 function Hash (F : Key) return Header_Num;
135 pragma Inline (Hash);
137 function Next (E : Elmt_Ptr) return Elmt_Ptr;
138 pragma Inline (Next);
140 procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr);
141 pragma Inline (Set_Next);
143 end Hash_Subprograms;
145 package body Hash_Subprograms is
151 function Equal (F1, F2 : Key) return Boolean is
160 function Get_Key (E : Elmt_Ptr) return Key is
162 return E.Entity_Name;
169 function Hash (F : Key) return Header_Num is
171 return Header_Num (Int (F) mod 1024);
178 function Next (E : Elmt_Ptr) return Elmt_Ptr is
187 procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr) is
191 end Hash_Subprograms;
197 -- The following table records the data for each pragmas, using the
198 -- entity name as the hash key for retrieval. Entries in this table
199 -- are set by Process_Eliminate_Pragma and read by Check_Eliminated.
201 package Elim_Hash_Table is new Static_HTable (
202 Header_Num => Header_Num,
204 Elmt_Ptr => Elmt_Ptr,
205 Null_Ptr => Null_Ptr,
206 Set_Next => Hash_Subprograms.Set_Next,
207 Next => Hash_Subprograms.Next,
209 Get_Key => Hash_Subprograms.Get_Key,
210 Hash => Hash_Subprograms.Hash,
211 Equal => Hash_Subprograms.Equal);
213 -- The following table records entities for subprograms that are
214 -- eliminated, and corresponding eliminate pragmas that caused the
215 -- elimination. Entries in this table are set by Check_Eliminated
216 -- and read by Eliminate_Error_Msg.
218 type Elim_Entity_Entry is record
223 package Elim_Entities is new Table.Table (
224 Table_Component_Type => Elim_Entity_Entry,
225 Table_Index_Type => Name_Id'Base,
226 Table_Low_Bound => First_Name_Id,
228 Table_Increment => 200,
229 Table_Name => "Elim_Entries");
231 ----------------------
232 -- Check_Eliminated --
233 ----------------------
235 procedure Check_Eliminated (E : Entity_Id) is
236 Elmt : Access_Elim_Data;
242 if No_Elimination then
245 -- Elimination of objects and types is not implemented yet
247 elsif Ekind (E) not in Subprogram_Kind then
251 -- Loop through homonyms for this key
253 Elmt := Elim_Hash_Table.Get (Chars (E));
254 while Elmt /= null loop
255 Check_Homonyms : declare
256 procedure Set_Eliminated;
257 -- Set current subprogram entity as eliminated
263 procedure Set_Eliminated is
265 if Is_Dispatching_Operation (E) then
267 -- If an overriding dispatching primitive is eliminated then
268 -- its parent must have been eliminated.
270 if Is_Overriding_Operation (E)
271 and then not Is_Eliminated (Overridden_Operation (E))
273 Error_Msg_Name_1 := Chars (E);
274 Error_Msg_N ("cannot eliminate subprogram %", E);
279 Set_Is_Eliminated (E);
280 Elim_Entities.Append ((Prag => Elmt.Prag, Subp => E));
283 -- Start of processing for Check_Homonyms
286 -- First we check that the name of the entity matches
288 if Elmt.Entity_Name /= Chars (E) then
292 -- Find enclosing unit, and verify that its name and those of its
295 Scop := Cunit_Entity (Current_Sem_Unit);
297 -- Now see if compilation unit matches
299 Up := Elmt.Unit_Name'Last;
301 -- If we are within a subunit, the name in the pragma has been
302 -- parsed as a child unit, but the current compilation unit is in
303 -- fact the parent in which the subunit is embedded. We must skip
304 -- the first name which is that of the subunit to match the pragma
305 -- specification. Body may be that of a package or subprogram.
312 while Present (Par) loop
313 if Nkind (Par) = N_Subunit then
314 if Chars (Defining_Entity (Proper_Body (Par))) =
329 for J in reverse Elmt.Unit_Name'First .. Up loop
330 if Elmt.Unit_Name (J) /= Chars (Scop) then
334 Scop := Scope (Scop);
336 if Scop /= Standard_Standard and then J = 1 then
341 if Scop /= Standard_Standard then
345 if Present (Elmt.Entity_Node)
346 and then Elmt.Entity_Scope /= null
348 -- Check that names of enclosing scopes match. Skip blocks and
349 -- wrapper package of subprogram instances, which do not appear
354 for J in reverse Elmt.Entity_Scope'Range loop
355 while Ekind (Scop) = E_Block
357 (Ekind (Scop) = E_Package
358 and then Is_Wrapper_Package (Scop))
360 Scop := Scope (Scop);
363 if Elmt.Entity_Scope (J) /= Chars (Scop) then
364 if Ekind (Scop) /= E_Protected_Type
365 or else Comes_From_Source (Scop)
369 -- For simple protected declarations, retrieve the source
370 -- name of the object, which appeared in the Eliminate
375 Decl : constant Node_Id :=
376 Original_Node (Parent (Scop));
379 if Elmt.Entity_Scope (J) /=
380 Chars (Defining_Identifier (Decl))
392 Scop := Scope (Scop);
396 -- If given entity is a library level subprogram and pragma had a
397 -- single parameter, a match!
399 if Is_Compilation_Unit (E)
400 and then Is_Subprogram (E)
401 and then No (Elmt.Entity_Node)
406 -- Check for case of type or object with two parameter case
408 elsif (Is_Type (E) or else Is_Object (E))
409 and then Elmt.Result_Type = No_Name
410 and then Elmt.Parameter_Types = null
415 -- Check for case of subprogram
417 elsif Ekind_In (E, E_Function, E_Procedure) then
419 -- If Source_Location present, then see if it matches
421 if Elmt.Source_Location /= No_Name then
422 Get_Name_String (Elmt.Source_Location);
425 Sloc_Trace : constant String :=
426 Name_Buffer (1 .. Name_Len);
428 Idx : Natural := Sloc_Trace'First;
429 -- Index in Sloc_Trace, if equals to 0, then we have
430 -- completely traversed Sloc_Trace
432 Last : constant Natural := Sloc_Trace'Last;
435 Sindex : Source_File_Index;
437 function File_Name_Match return Boolean;
438 -- This function is supposed to be called when Idx points
439 -- to the beginning of the new file name, and Name_Buffer
440 -- is set to contain the name of the proper source file
441 -- from the chain corresponding to the Sloc of E. First
442 -- it checks that these two files have the same name. If
443 -- this check is successful, moves Idx to point to the
444 -- beginning of the column number.
446 function Line_Num_Match return Boolean;
447 -- This function is supposed to be called when Idx points
448 -- to the beginning of the column number, and P is
449 -- set to point to the proper Sloc the chain
450 -- corresponding to the Sloc of E. First it checks that
451 -- the line number Idx points on and the line number
452 -- corresponding to P are the same. If this check is
453 -- successful, moves Idx to point to the beginning of
454 -- the next file name in Sloc_Trace. If there is no file
455 -- name any more, Idx is set to 0.
457 function Different_Trace_Lengths return Boolean;
458 -- From Idx and P, defines if there are in both traces
459 -- more element(s) in the instantiation chains. Returns
460 -- False if one trace contains more element(s), but
461 -- another does not. If both traces contains more
462 -- elements (that is, the function returns False), moves
463 -- P ahead in the chain corresponding to E, recomputes
464 -- Sindex and sets the name of the corresponding file in
467 function Skip_Spaces return Natural;
468 -- If Sloc_Trace (Idx) is not space character, returns
469 -- Idx. Otherwise returns the index of the nearest
470 -- non-space character in Sloc_Trace to the right of Idx.
471 -- Returns 0 if there is no such character.
473 -----------------------------
474 -- Different_Trace_Lengths --
475 -----------------------------
477 function Different_Trace_Lengths return Boolean is
479 P := Instantiation (Sindex);
481 if (P = No_Location and then Idx /= 0)
483 (P /= No_Location and then Idx = 0)
488 if P /= No_Location then
489 Sindex := Get_Source_File_Index (P);
490 Get_Name_String (File_Name (Sindex));
495 end Different_Trace_Lengths;
497 ---------------------
498 -- File_Name_Match --
499 ---------------------
501 function File_Name_Match return Boolean is
510 -- Find first colon. If no colon, then return False.
511 -- If there is a colon, Tmp_Idx is set to point just
516 if Tmp_Idx >= Last then
518 elsif Sloc_Trace (Tmp_Idx + 1) = ':' then
521 Tmp_Idx := Tmp_Idx + 1;
525 -- Find last non-space before this colon. If there is
526 -- no space character before this colon, then return
527 -- False. Otherwise, End_Idx is set to point to this
528 -- non-space character.
532 if End_Idx < Idx then
535 elsif Sloc_Trace (End_Idx) /= ' ' then
539 End_Idx := End_Idx - 1;
543 -- Now see if file name matches what is in Name_Buffer
544 -- and if so, step Idx past it and return True. If the
545 -- name does not match, return False.
547 if Sloc_Trace (Idx .. End_Idx) =
548 Name_Buffer (1 .. Name_Len)
562 function Line_Num_Match return Boolean is
571 and then Sloc_Trace (Idx) in '0' .. '9'
574 (Character'Pos (Sloc_Trace (Idx)) -
575 Character'Pos ('0'));
579 if Get_Physical_Line_Number (P) =
580 Physical_Line_Number (N)
582 while Idx <= Last and then
583 Sloc_Trace (Idx) /= '['
588 if Idx <= Last and then
589 Sloc_Trace (Idx) = '['
608 function Skip_Spaces return Natural is
613 while Sloc_Trace (Res) = ' ' loop
627 Sindex := Get_Source_File_Index (P);
628 Get_Name_String (File_Name (Sindex));
632 if not File_Name_Match then
634 elsif not Line_Num_Match then
638 if Different_Trace_Lengths then
645 -- If we have a Result_Type, then we must have a function with
646 -- the proper result type.
648 if Elmt.Result_Type /= No_Name then
649 if Ekind (E) /= E_Function
650 or else Chars (Etype (E)) /= Elmt.Result_Type
656 -- If we have Parameter_Types, they must match
658 if Elmt.Parameter_Types /= null then
659 Form := First_Formal (E);
662 and then Elmt.Parameter_Types'Length = 1
663 and then Elmt.Parameter_Types (1) = No_Name
665 -- Parameterless procedure matches
669 elsif Elmt.Parameter_Types = null then
673 for J in Elmt.Parameter_Types'Range loop
676 Chars (Etype (Form)) /= Elmt.Parameter_Types (J)
684 if Present (Form) then
690 -- If we fall through, this is match
698 Elmt := Elmt.Homonym;
702 end Check_Eliminated;
704 -------------------------------------
705 -- Check_For_Eliminated_Subprogram --
706 -------------------------------------
708 procedure Check_For_Eliminated_Subprogram (N : Node_Id; S : Entity_Id) is
709 Ultimate_Subp : constant Entity_Id := Ultimate_Alias (S);
710 Enclosing_Subp : Entity_Id;
713 if Is_Eliminated (Ultimate_Subp)
714 and then not Inside_A_Generic
715 and then not Is_Generic_Unit (Cunit_Entity (Current_Sem_Unit))
717 Enclosing_Subp := Current_Subprogram;
718 while Present (Enclosing_Subp) loop
719 if Is_Eliminated (Enclosing_Subp) then
723 Enclosing_Subp := Enclosing_Subprogram (Enclosing_Subp);
726 -- Emit error, unless we are within an instance body and the expander
727 -- is disabled, indicating an instance within an enclosing generic.
728 -- In an instance, the ultimate alias is an internal entity, so place
729 -- the message on the original subprogram.
731 if In_Instance_Body and then not Expander_Active then
734 elsif Comes_From_Source (Ultimate_Subp) then
735 Eliminate_Error_Msg (N, Ultimate_Subp);
738 Eliminate_Error_Msg (N, S);
741 end Check_For_Eliminated_Subprogram;
743 -------------------------
744 -- Eliminate_Error_Msg --
745 -------------------------
747 procedure Eliminate_Error_Msg (N : Node_Id; E : Entity_Id) is
749 for J in Elim_Entities.First .. Elim_Entities.Last loop
750 if E = Elim_Entities.Table (J).Subp then
751 Error_Msg_Sloc := Sloc (Elim_Entities.Table (J).Prag);
752 Error_Msg_NE ("cannot reference subprogram & eliminated #", N, E);
757 -- If this is an internal operation generated for a protected operation,
758 -- its name does not match the source name, so just report the error.
760 if not Comes_From_Source (E)
761 and then Present (First_Entity (E))
762 and then Is_Concurrent_Record_Type (Etype (First_Entity (E)))
765 ("cannot reference eliminated protected subprogram", N, E);
767 -- Otherwise should not fall through, entry should be in table
771 ("subprogram& is called but its alias is eliminated", N, E);
772 -- raise Program_Error;
774 end Eliminate_Error_Msg;
780 procedure Initialize is
782 Elim_Hash_Table.Reset;
784 No_Elimination := True;
787 ------------------------------
788 -- Process_Eliminate_Pragma --
789 ------------------------------
791 procedure Process_Eliminate_Pragma
792 (Pragma_Node : Node_Id;
793 Arg_Unit_Name : Node_Id;
794 Arg_Entity : Node_Id;
795 Arg_Parameter_Types : Node_Id;
796 Arg_Result_Type : Node_Id;
797 Arg_Source_Location : Node_Id)
799 Data : constant Access_Elim_Data := new Elim_Data;
800 -- Build result data here
802 Elmt : Access_Elim_Data;
804 Num_Names : Nat := 0;
805 -- Number of names in unit name
811 function OK_Selected_Component (N : Node_Id) return Boolean;
812 -- Test if N is a selected component with all identifiers, or a
813 -- selected component whose selector is an operator symbol. As a
814 -- side effect if result is True, sets Num_Names to the number
815 -- of names present (identifiers and operator if any).
817 ---------------------------
818 -- OK_Selected_Component --
819 ---------------------------
821 function OK_Selected_Component (N : Node_Id) return Boolean is
823 if Nkind (N) = N_Identifier
824 or else Nkind (N) = N_Operator_Symbol
826 Num_Names := Num_Names + 1;
829 elsif Nkind (N) = N_Selected_Component then
830 return OK_Selected_Component (Prefix (N))
831 and then OK_Selected_Component (Selector_Name (N));
836 end OK_Selected_Component;
838 -- Start of processing for Process_Eliminate_Pragma
841 Data.Prag := Pragma_Node;
842 Error_Msg_Name_1 := Name_Eliminate;
844 -- Process Unit_Name argument
846 if Nkind (Arg_Unit_Name) = N_Identifier then
847 Data.Unit_Name := new Names'(1 => Chars (Arg_Unit_Name));
850 elsif OK_Selected_Component (Arg_Unit_Name) then
851 Data.Unit_Name := new Names (1 .. Num_Names);
853 Arg_Uname := Arg_Unit_Name;
854 for J in reverse 2 .. Num_Names loop
855 Data.Unit_Name (J) := Chars (Selector_Name (Arg_Uname));
856 Arg_Uname := Prefix (Arg_Uname);
859 Data.Unit_Name (1) := Chars (Arg_Uname);
863 ("wrong form for Unit_Name parameter of pragma%", Arg_Unit_Name);
867 -- Process Entity argument
869 if Present (Arg_Entity) then
872 if Nkind (Arg_Entity) = N_Identifier
873 or else Nkind (Arg_Entity) = N_Operator_Symbol
875 Data.Entity_Name := Chars (Arg_Entity);
876 Data.Entity_Node := Arg_Entity;
877 Data.Entity_Scope := null;
879 elsif OK_Selected_Component (Arg_Entity) then
880 Data.Entity_Scope := new Names (1 .. Num_Names - 1);
881 Data.Entity_Name := Chars (Selector_Name (Arg_Entity));
882 Data.Entity_Node := Arg_Entity;
884 Arg_Ent := Prefix (Arg_Entity);
885 for J in reverse 2 .. Num_Names - 1 loop
886 Data.Entity_Scope (J) := Chars (Selector_Name (Arg_Ent));
887 Arg_Ent := Prefix (Arg_Ent);
890 Data.Entity_Scope (1) := Chars (Arg_Ent);
892 elsif Is_Config_Static_String (Arg_Entity) then
893 Data.Entity_Name := Name_Find;
894 Data.Entity_Node := Arg_Entity;
900 Data.Entity_Node := Empty;
901 Data.Entity_Name := Data.Unit_Name (Num_Names);
904 -- Process Parameter_Types argument
906 if Present (Arg_Parameter_Types) then
908 -- Here for aggregate case
910 if Nkind (Arg_Parameter_Types) = N_Aggregate then
911 Data.Parameter_Types :=
913 (1 .. List_Length (Expressions (Arg_Parameter_Types)));
915 Lit := First (Expressions (Arg_Parameter_Types));
916 for J in Data.Parameter_Types'Range loop
917 if Is_Config_Static_String (Lit) then
918 Data.Parameter_Types (J) := Name_Find;
925 -- Otherwise we must have case of one name, which looks like a
926 -- parenthesized literal rather than an aggregate.
928 elsif Paren_Count (Arg_Parameter_Types) /= 1 then
930 ("wrong form for argument of pragma Eliminate",
931 Arg_Parameter_Types);
934 elsif Is_Config_Static_String (Arg_Parameter_Types) then
935 String_To_Name_Buffer (Strval (Arg_Parameter_Types));
939 -- Parameterless procedure
941 Data.Parameter_Types := new Names'(1 => No_Name);
944 Data.Parameter_Types := new Names'(1 => Name_Find);
952 -- Process Result_Types argument
954 if Present (Arg_Result_Type) then
955 if Is_Config_Static_String (Arg_Result_Type) then
956 Data.Result_Type := Name_Find;
961 -- Here if no Result_Types argument
964 Data.Result_Type := No_Name;
967 -- Process Source_Location argument
969 if Present (Arg_Source_Location) then
970 if Is_Config_Static_String (Arg_Source_Location) then
971 Data.Source_Location := Name_Find;
976 Data.Source_Location := No_Name;
979 Elmt := Elim_Hash_Table.Get (Hash_Subprograms.Get_Key (Data));
981 -- If we already have an entry with this same key, then link
982 -- it into the chain of entries for this key.
985 Data.Homonym := Elmt.Homonym;
986 Elmt.Homonym := Data;
988 -- Otherwise create a new entry
991 Elim_Hash_Table.Set (Data);
994 No_Elimination := False;
995 end Process_Eliminate_Pragma;