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2009-12-01 Thomas Quinot <quinot@adacore.com>
[pf3gnuchains/gcc-fork.git] / gcc / ada / sem_scil.adb
1 ------------------------------------------------------------------------------
2 --                                                                          --
3 --                         GNAT COMPILER COMPONENTS                         --
4 --                                                                          --
5 --                             S E M _ S C I L                              --
6 --                                                                          --
7 --                                 B o d y                                  --
8 --                                                                          --
9 --             Copyright (C) 2009, Free Software Foundation, Inc.           --
10 --                                                                          --
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.          --
20 --                                                                          --
21 -- GNAT was originally developed  by the GNAT team at  New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
23 --                                                                          --
24 ------------------------------------------------------------------------------
25
26 with Einfo;    use Einfo;
27 with Namet;    use Namet;
28 with Nlists;   use Nlists;
29 with Opt;      use Opt;
30 with Rtsfind;  use Rtsfind;
31 with Sem;      use Sem;
32 with Sem_Aux;  use Sem_Aux;
33 with Sem_Util; use Sem_Util;
34 with Sinfo;    use Sinfo;
35 with Snames;   use Snames;
36 with Stand;    use Stand;
37
38 package body Sem_SCIL is
39
40    ----------------------
41    -- Adjust_SCIL_Node --
42    ----------------------
43
44    procedure Adjust_SCIL_Node (Old_Node : Node_Id; New_Node : Node_Id) is
45       SCIL_Node : Node_Id;
46
47    begin
48       pragma Assert (Generate_SCIL);
49
50       --  Check cases in which no action is required. Currently the only SCIL
51       --  nodes that may require adjustment are those of dispatching calls
52       --  internally generated by the frontend.
53
54       if Comes_From_Source (Old_Node)
55         or else not
56           Nkind_In (New_Node, N_Function_Call, N_Procedure_Call_Statement)
57       then
58          return;
59
60       --  Conditional expression associated with equality operator. Old_Node
61       --  may be part of the expansion of the predefined equality operator of
62       --  a tagged type and hence we need to check if it has a SCIL dispatching
63       --  node that needs adjustment.
64
65       elsif Nkind (Old_Node) = N_Conditional_Expression
66         and then (Nkind (Original_Node (Old_Node)) = N_Op_Eq
67                     or else
68                       (Nkind (Original_Node (Old_Node)) = N_Function_Call
69                         and then Chars (Name (Original_Node (Old_Node))) =
70                                                                  Name_Op_Eq))
71       then
72          null;
73
74       --  Type conversions may involve dispatching calls to functions whose
75       --  associated SCIL dispatching node needs adjustment.
76
77       elsif Nkind_In (Old_Node, N_Type_Conversion,
78                                 N_Unchecked_Type_Conversion)
79       then
80          null;
81
82       --  Relocated subprogram call
83
84       elsif Nkind (Old_Node) = Nkind (New_Node)
85         and then Original_Node (Old_Node) = Original_Node (New_Node)
86       then
87          null;
88
89       else
90          return;
91       end if;
92
93       --  Search for the SCIL node and update it (if found)
94
95       SCIL_Node := Find_SCIL_Node (Old_Node);
96
97       if Present (SCIL_Node) then
98          Set_SCIL_Related_Node (SCIL_Node, New_Node);
99       end if;
100    end Adjust_SCIL_Node;
101
102    ---------------------
103    -- Check_SCIL_Node --
104    ---------------------
105
106    function Check_SCIL_Node (N : Node_Id) return Traverse_Result is
107       Ctrl_Tag : Node_Id;
108       Ctrl_Typ : Entity_Id;
109
110    begin
111       if Nkind (N) = N_SCIL_Membership_Test then
112
113          --  Check contents of the boolean expression associated with the
114          --  membership test.
115
116          pragma Assert (Nkind (SCIL_Related_Node (N)) = N_Identifier
117            and then Etype (SCIL_Related_Node (N)) = Standard_Boolean);
118
119          --  Check the entity identifier of the associated tagged type (that
120          --  is, in testing for membership in T'Class, the entity id of the
121          --  specific type T).
122
123          --  Note: When the SCIL node is generated the private and full-view
124          --    of the tagged types may have been swapped and hence the node
125          --    referenced by attribute SCIL_Entity may be the private view.
126          --    Therefore, in order to uniformily locate the full-view we use
127          --    attribute Underlying_Type.
128
129          pragma Assert (Is_Tagged_Type (Underlying_Type (SCIL_Entity (N))));
130
131          --  Interface types are unsupported
132
133          pragma Assert (not Is_Interface (Underlying_Type (SCIL_Entity (N))));
134
135          --  Check the decoration of the expression that denotes the tag value
136          --  being tested
137
138          Ctrl_Tag := SCIL_Tag_Value (N);
139
140          case Nkind (Ctrl_Tag) is
141
142             --  For class-wide membership tests the SCIL tag value is the tag
143             --  of the tested object (i.e. Obj.Tag).
144
145             when N_Selected_Component =>
146                pragma Assert (Etype (Ctrl_Tag) = RTE (RE_Tag));
147                null;
148
149             when others =>
150                pragma Assert (False);
151                null;
152
153          end case;
154
155          return Skip;
156
157       elsif Nkind (N) = N_SCIL_Dispatching_Call then
158          Ctrl_Tag := SCIL_Controlling_Tag (N);
159
160          --  SCIL_Related_Node of SCIL dispatching call nodes MUST reference
161          --  subprogram calls.
162
163          if not Nkind_In (SCIL_Related_Node (N), N_Function_Call,
164                                                  N_Procedure_Call_Statement)
165          then
166             pragma Assert (False);
167             raise Program_Error;
168
169          --  In simple cases the controlling tag is the tag of the controlling
170          --  argument (i.e. Obj.Tag).
171
172          elsif Nkind (Ctrl_Tag) = N_Selected_Component then
173             Ctrl_Typ := Etype (Ctrl_Tag);
174
175             --  Interface types are unsupported
176
177             if Is_Interface (Ctrl_Typ)
178               or else (RTE_Available (RE_Interface_Tag)
179                          and then Ctrl_Typ = RTE (RE_Interface_Tag))
180             then
181                null;
182
183             else
184                pragma Assert (Ctrl_Typ = RTE (RE_Tag));
185                null;
186             end if;
187
188          --  When the controlling tag of a dispatching call is an identifier
189          --  the SCIL_Controlling_Tag attribute references the corresponding
190          --  object or parameter declaration. Interface types are still
191          --  unsupported.
192
193          elsif Nkind_In (Ctrl_Tag, N_Object_Declaration,
194                                    N_Parameter_Specification)
195          then
196             Ctrl_Typ := Etype (Defining_Identifier (Ctrl_Tag));
197
198             --  Interface types are unsupported.
199
200             if Is_Interface (Ctrl_Typ)
201               or else (RTE_Available (RE_Interface_Tag)
202                         and then Ctrl_Typ = RTE (RE_Interface_Tag))
203               or else (Is_Access_Type (Ctrl_Typ)
204                         and then
205                           Is_Interface
206                             (Available_View
207                               (Base_Type (Designated_Type (Ctrl_Typ)))))
208             then
209                null;
210
211             else
212                pragma Assert
213                  (Ctrl_Typ = RTE (RE_Tag)
214                     or else
215                       (Is_Access_Type (Ctrl_Typ)
216                         and then Available_View
217                                   (Base_Type (Designated_Type (Ctrl_Typ))) =
218                                                                 RTE (RE_Tag)));
219                null;
220             end if;
221
222          --  Interface types are unsupported
223
224          elsif Is_Interface (Etype (Ctrl_Tag)) then
225             null;
226
227          else
228             pragma Assert (False);
229             raise Program_Error;
230          end if;
231
232          return Skip;
233
234       --  Node is not N_SCIL_Dispatching_Call
235
236       else
237          return OK;
238       end if;
239    end Check_SCIL_Node;
240
241    --------------------
242    -- Find_SCIL_Node --
243    --------------------
244
245    function Find_SCIL_Node (Node : Node_Id) return Node_Id is
246       Found_Node : Node_Id;
247       --  This variable stores the last node found by the nested subprogram
248       --  Find_SCIL_Node.
249
250       function Find_SCIL_Node (L : List_Id) return Boolean;
251       --  Searches in list L for a SCIL node associated with a dispatching call
252       --  whose SCIL_Related_Node is Node. If found returns true and stores the
253       --  SCIL node in Found_Node; otherwise returns False and sets Found_Node
254       --  to Empty.
255
256       --------------------
257       -- Find_SCIL_Node --
258       --------------------
259
260       function Find_SCIL_Node (L : List_Id) return Boolean is
261          N : Node_Id;
262
263       begin
264          N := First (L);
265          while Present (N) loop
266             if Nkind (N) in N_SCIL_Node
267               and then SCIL_Related_Node (N) = Node
268             then
269                Found_Node := N;
270                return True;
271             end if;
272
273             Next (N);
274          end loop;
275
276          Found_Node := Empty;
277          return False;
278       end Find_SCIL_Node;
279
280       --  Local variables
281
282       P : Node_Id;
283
284    --  Start of processing for Find_SCIL_Node
285
286    begin
287       pragma Assert (Generate_SCIL);
288
289       --  Search for the SCIL node in list associated with a transient scope
290
291       if Scope_Is_Transient then
292          declare
293             SE : Scope_Stack_Entry
294                    renames Scope_Stack.Table (Scope_Stack.Last);
295          begin
296             if SE.Is_Transient
297               and then Present (SE.Actions_To_Be_Wrapped_Before)
298               and then Find_SCIL_Node (SE.Actions_To_Be_Wrapped_Before)
299             then
300                return Found_Node;
301             end if;
302          end;
303       end if;
304
305       --  Otherwise climb up the tree searching for the SCIL node analyzing
306       --  all the lists in which Insert_Actions may have inserted it
307
308       P := Node;
309       while Present (P) loop
310          case Nkind (P) is
311
312             --  Actions associated with AND THEN or OR ELSE
313
314             when N_Short_Circuit =>
315                if Present (Actions (P))
316                  and then Find_SCIL_Node (Actions (P))
317                then
318                   return Found_Node;
319                end if;
320
321             --  Actions of conditional expressions
322
323             when N_Conditional_Expression =>
324                if (Present (Then_Actions (P))
325                     and then Find_SCIL_Node (Actions (P)))
326                  or else
327                   (Present (Else_Actions (P))
328                     and then Find_SCIL_Node (Else_Actions (P)))
329                then
330                   return Found_Node;
331                end if;
332
333             --  Actions in handled sequence of statements
334
335             when
336                N_Handled_Sequence_Of_Statements =>
337                   if Find_SCIL_Node (Statements (P)) then
338                      return Found_Node;
339                   end if;
340
341             --  Conditions of while expression or elsif.
342
343             when N_Iteration_Scheme |
344                  N_Elsif_Part
345             =>
346                if Present (Condition_Actions (P))
347                  and then Find_SCIL_Node (Condition_Actions (P))
348                then
349                   return Found_Node;
350                end if;
351
352             --  Statements, declarations, pragmas, representation clauses
353
354             when
355                --  Statements
356
357                N_Procedure_Call_Statement               |
358                N_Statement_Other_Than_Procedure_Call    |
359
360                --  Pragmas
361
362                N_Pragma                                 |
363
364                --  Representation_Clause
365
366                N_At_Clause                              |
367                N_Attribute_Definition_Clause            |
368                N_Enumeration_Representation_Clause      |
369                N_Record_Representation_Clause           |
370
371                --  Declarations
372
373                N_Abstract_Subprogram_Declaration        |
374                N_Entry_Body                             |
375                N_Exception_Declaration                  |
376                N_Exception_Renaming_Declaration         |
377                N_Formal_Abstract_Subprogram_Declaration |
378                N_Formal_Concrete_Subprogram_Declaration |
379                N_Formal_Object_Declaration              |
380                N_Formal_Type_Declaration                |
381                N_Full_Type_Declaration                  |
382                N_Function_Instantiation                 |
383                N_Generic_Function_Renaming_Declaration  |
384                N_Generic_Package_Declaration            |
385                N_Generic_Package_Renaming_Declaration   |
386                N_Generic_Procedure_Renaming_Declaration |
387                N_Generic_Subprogram_Declaration         |
388                N_Implicit_Label_Declaration             |
389                N_Incomplete_Type_Declaration            |
390                N_Number_Declaration                     |
391                N_Object_Declaration                     |
392                N_Object_Renaming_Declaration            |
393                N_Package_Body                           |
394                N_Package_Body_Stub                      |
395                N_Package_Declaration                    |
396                N_Package_Instantiation                  |
397                N_Package_Renaming_Declaration           |
398                N_Private_Extension_Declaration          |
399                N_Private_Type_Declaration               |
400                N_Procedure_Instantiation                |
401                N_Protected_Body                         |
402                N_Protected_Body_Stub                    |
403                N_Protected_Type_Declaration             |
404                N_Single_Task_Declaration                |
405                N_Subprogram_Body                        |
406                N_Subprogram_Body_Stub                   |
407                N_Subprogram_Declaration                 |
408                N_Subprogram_Renaming_Declaration        |
409                N_Subtype_Declaration                    |
410                N_Task_Body                              |
411                N_Task_Body_Stub                         |
412                N_Task_Type_Declaration                  |
413
414                --  Freeze entity behaves like a declaration or statement
415
416                N_Freeze_Entity
417             =>
418                --  Do not search here if the item is not a list member
419
420                if not Is_List_Member (P) then
421                   null;
422
423                --  Do not search if parent of P is an N_Component_Association
424                --  node (i.e. we are in the context of an N_Aggregate or
425                --  N_Extension_Aggregate node). In this case the node should
426                --  have been added before the entire aggregate.
427
428                elsif Nkind (Parent (P)) = N_Component_Association then
429                   null;
430
431                --  Do not search if the parent of P is either an N_Variant
432                --  node or an N_Record_Definition node. In this case the node
433                --  should have been added before the entire record.
434
435                elsif Nkind (Parent (P)) = N_Variant
436                  or else Nkind (Parent (P)) = N_Record_Definition
437                then
438                   null;
439
440                --  Otherwise search it in the list containing this node
441
442                elsif Find_SCIL_Node (List_Containing (P)) then
443                   return Found_Node;
444                end if;
445
446             --  A special case, N_Raise_xxx_Error can act either as a statement
447             --  or a subexpression. We diferentiate them by looking at the
448             --  Etype. It is set to Standard_Void_Type in the statement case.
449
450             when
451                N_Raise_xxx_Error =>
452                   if Etype (P) = Standard_Void_Type then
453                      if Is_List_Member (P)
454                        and then Find_SCIL_Node (List_Containing (P))
455                      then
456                         return Found_Node;
457                      end if;
458
459                   --  In the subexpression case, keep climbing
460
461                   else
462                      null;
463                   end if;
464
465             --  If a component association appears within a loop created for
466             --  an array aggregate, check if the SCIL node was added to the
467             --  the list of nodes attached to the association.
468
469             when
470                N_Component_Association =>
471                   if Nkind (Parent (P)) = N_Aggregate
472                     and then Present (Loop_Actions (P))
473                     and then Find_SCIL_Node (Loop_Actions (P))
474                   then
475                      return Found_Node;
476                   end if;
477
478             --  Another special case, an attribute denoting a procedure call
479
480             when
481                N_Attribute_Reference =>
482                   if Is_Procedure_Attribute_Name (Attribute_Name (P))
483                     and then Find_SCIL_Node (List_Containing (P))
484                   then
485                      return Found_Node;
486
487                   --  In the subexpression case, keep climbing
488
489                   else
490                      null;
491                   end if;
492
493             --  SCIL nodes do not have subtrees and hence they can never be
494             --  found climbing tree
495
496             when
497                N_SCIL_Dispatch_Table_Object_Init        |
498                N_SCIL_Dispatch_Table_Tag_Init           |
499                N_SCIL_Dispatching_Call                  |
500                N_SCIL_Membership_Test                   |
501                N_SCIL_Tag_Init
502             =>
503                pragma Assert (False);
504                raise Program_Error;
505
506             --  For all other node types, keep climbing tree
507
508             when
509                N_Abortable_Part                         |
510                N_Accept_Alternative                     |
511                N_Access_Definition                      |
512                N_Access_Function_Definition             |
513                N_Access_Procedure_Definition            |
514                N_Access_To_Object_Definition            |
515                N_Aggregate                              |
516                N_Allocator                              |
517                N_Case_Statement_Alternative             |
518                N_Character_Literal                      |
519                N_Compilation_Unit                       |
520                N_Compilation_Unit_Aux                   |
521                N_Component_Clause                       |
522                N_Component_Declaration                  |
523                N_Component_Definition                   |
524                N_Component_List                         |
525                N_Constrained_Array_Definition           |
526                N_Decimal_Fixed_Point_Definition         |
527                N_Defining_Character_Literal             |
528                N_Defining_Identifier                    |
529                N_Defining_Operator_Symbol               |
530                N_Defining_Program_Unit_Name             |
531                N_Delay_Alternative                      |
532                N_Delta_Constraint                       |
533                N_Derived_Type_Definition                |
534                N_Designator                             |
535                N_Digits_Constraint                      |
536                N_Discriminant_Association               |
537                N_Discriminant_Specification             |
538                N_Empty                                  |
539                N_Entry_Body_Formal_Part                 |
540                N_Entry_Call_Alternative                 |
541                N_Entry_Declaration                      |
542                N_Entry_Index_Specification              |
543                N_Enumeration_Type_Definition            |
544                N_Error                                  |
545                N_Exception_Handler                      |
546                N_Expanded_Name                          |
547                N_Explicit_Dereference                   |
548                N_Extension_Aggregate                    |
549                N_Floating_Point_Definition              |
550                N_Formal_Decimal_Fixed_Point_Definition  |
551                N_Formal_Derived_Type_Definition         |
552                N_Formal_Discrete_Type_Definition        |
553                N_Formal_Floating_Point_Definition       |
554                N_Formal_Modular_Type_Definition         |
555                N_Formal_Ordinary_Fixed_Point_Definition |
556                N_Formal_Package_Declaration             |
557                N_Formal_Private_Type_Definition         |
558                N_Formal_Signed_Integer_Type_Definition  |
559                N_Function_Call                          |
560                N_Function_Specification                 |
561                N_Generic_Association                    |
562                N_Identifier                             |
563                N_In                                     |
564                N_Index_Or_Discriminant_Constraint       |
565                N_Indexed_Component                      |
566                N_Integer_Literal                        |
567                N_Itype_Reference                        |
568                N_Label                                  |
569                N_Loop_Parameter_Specification           |
570                N_Mod_Clause                             |
571                N_Modular_Type_Definition                |
572                N_Not_In                                 |
573                N_Null                                   |
574                N_Op_Abs                                 |
575                N_Op_Add                                 |
576                N_Op_And                                 |
577                N_Op_Concat                              |
578                N_Op_Divide                              |
579                N_Op_Eq                                  |
580                N_Op_Expon                               |
581                N_Op_Ge                                  |
582                N_Op_Gt                                  |
583                N_Op_Le                                  |
584                N_Op_Lt                                  |
585                N_Op_Minus                               |
586                N_Op_Mod                                 |
587                N_Op_Multiply                            |
588                N_Op_Ne                                  |
589                N_Op_Not                                 |
590                N_Op_Or                                  |
591                N_Op_Plus                                |
592                N_Op_Rem                                 |
593                N_Op_Rotate_Left                         |
594                N_Op_Rotate_Right                        |
595                N_Op_Shift_Left                          |
596                N_Op_Shift_Right                         |
597                N_Op_Shift_Right_Arithmetic              |
598                N_Op_Subtract                            |
599                N_Op_Xor                                 |
600                N_Operator_Symbol                        |
601                N_Ordinary_Fixed_Point_Definition        |
602                N_Others_Choice                          |
603                N_Package_Specification                  |
604                N_Parameter_Association                  |
605                N_Parameter_Specification                |
606                N_Pop_Constraint_Error_Label             |
607                N_Pop_Program_Error_Label                |
608                N_Pop_Storage_Error_Label                |
609                N_Pragma_Argument_Association            |
610                N_Procedure_Specification                |
611                N_Protected_Definition                   |
612                N_Push_Constraint_Error_Label            |
613                N_Push_Program_Error_Label               |
614                N_Push_Storage_Error_Label               |
615                N_Qualified_Expression                   |
616                N_Range                                  |
617                N_Range_Constraint                       |
618                N_Real_Literal                           |
619                N_Real_Range_Specification               |
620                N_Record_Definition                      |
621                N_Reference                              |
622                N_Selected_Component                     |
623                N_Signed_Integer_Type_Definition         |
624                N_Single_Protected_Declaration           |
625                N_Slice                                  |
626                N_String_Literal                         |
627                N_Subprogram_Info                        |
628                N_Subtype_Indication                     |
629                N_Subunit                                |
630                N_Task_Definition                        |
631                N_Terminate_Alternative                  |
632                N_Triggering_Alternative                 |
633                N_Type_Conversion                        |
634                N_Unchecked_Expression                   |
635                N_Unchecked_Type_Conversion              |
636                N_Unconstrained_Array_Definition         |
637                N_Unused_At_End                          |
638                N_Unused_At_Start                        |
639                N_Use_Package_Clause                     |
640                N_Use_Type_Clause                        |
641                N_Variant                                |
642                N_Variant_Part                           |
643                N_Validate_Unchecked_Conversion          |
644                N_With_Clause
645             =>
646                null;
647
648          end case;
649
650          --  If we fall through above tests, keep climbing tree
651
652          if Nkind (Parent (P)) = N_Subunit then
653
654             --  This is the proper body corresponding to a stub. Insertion done
655             --  at the point of the stub, which is in the declarative part of
656             --  the parent unit.
657
658             P := Corresponding_Stub (Parent (P));
659
660          else
661             P := Parent (P);
662          end if;
663       end loop;
664
665       --  SCIL node not found
666
667       return Empty;
668    end Find_SCIL_Node;
669
670    -------------------------
671    -- First_Non_SCIL_Node --
672    -------------------------
673
674    function First_Non_SCIL_Node (L : List_Id) return Node_Id is
675       N : Node_Id;
676
677    begin
678       N := First (L);
679       while Nkind (N) in N_SCIL_Node loop
680          Next (N);
681       end loop;
682
683       return N;
684    end First_Non_SCIL_Node;
685
686    ------------------------
687    -- Next_Non_SCIL_Node --
688    ------------------------
689
690    function Next_Non_SCIL_Node (N : Node_Id) return Node_Id is
691       Aux_N : Node_Id;
692
693    begin
694       Aux_N := Next (N);
695       while Nkind (Aux_N) in N_SCIL_Node loop
696          Next (Aux_N);
697       end loop;
698
699       return Aux_N;
700    end Next_Non_SCIL_Node;
701
702 end Sem_SCIL;