1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2006, 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 2, 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 COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 with Atree; use Atree;
28 with Checks; use Checks;
29 with Einfo; use Einfo;
30 with Exp_Ch3; use Exp_Ch3;
31 with Exp_Ch6; use Exp_Ch6;
32 with Exp_Imgv; use Exp_Imgv;
33 with Exp_Tss; use Exp_Tss;
34 with Exp_Util; use Exp_Util;
35 with Nlists; use Nlists;
36 with Nmake; use Nmake;
37 with Rtsfind; use Rtsfind;
39 with Sem_Ch7; use Sem_Ch7;
40 with Sem_Ch8; use Sem_Ch8;
41 with Sem_Eval; use Sem_Eval;
42 with Sem_Util; use Sem_Util;
43 with Sinfo; use Sinfo;
44 with Snames; use Snames;
45 with Stand; use Stand;
46 with Stringt; use Stringt;
47 with Tbuild; use Tbuild;
48 with Uintp; use Uintp;
50 package body Exp_Ch13 is
52 procedure Expand_External_Tag_Definition (N : Node_Id);
53 -- The code to assign and register an external tag must be elaborated
54 -- after the dispatch table has been created, so the expansion of the
55 -- attribute definition node is delayed until after the type is frozen.
57 ------------------------------------------
58 -- Expand_N_Attribute_Definition_Clause --
59 ------------------------------------------
61 -- Expansion action depends on attribute involved
63 procedure Expand_N_Attribute_Definition_Clause (N : Node_Id) is
64 Loc : constant Source_Ptr := Sloc (N);
65 Exp : constant Node_Id := Expression (N);
70 Ent := Entity (Name (N));
73 Ent := Underlying_Type (Ent);
76 case Get_Attribute_Id (Chars (N)) is
82 when Attribute_Address =>
84 -- If there is an initialization which did not come from the
85 -- source program, then it is an artifact of our expansion, and we
86 -- suppress it. The case we are most concerned about here is the
87 -- initialization of a packed array to all false, which seems
88 -- inappropriate for variable to which an address clause is
89 -- applied. The expression may itself have been rewritten if the
90 -- type is packed array, so we need to examine whether the
91 -- original node is in the source.
94 Decl : constant Node_Id := Declaration_Node (Ent);
96 if Nkind (Decl) = N_Object_Declaration
97 and then Present (Expression (Decl))
99 not Comes_From_Source (Original_Node (Expression (Decl)))
101 Set_Expression (Decl, Empty);
109 when Attribute_Alignment =>
111 -- As required by Gigi, we guarantee that the operand is an
112 -- integer literal (this simplifies things in Gigi).
114 if Nkind (Exp) /= N_Integer_Literal then
116 (Exp, Make_Integer_Literal (Loc, Expr_Value (Exp)));
123 when Attribute_Storage_Size =>
125 -- If the type is a task type, then assign the value of the
126 -- storage size to the Size variable associated with the task.
127 -- task_typeZ := expression
129 if Ekind (Ent) = E_Task_Type then
131 Make_Assignment_Statement (Loc,
132 Name => New_Reference_To (Storage_Size_Variable (Ent), Loc),
134 Convert_To (RTE (RE_Size_Type), Expression (N))));
136 -- For Storage_Size for an access type, create a variable to hold
137 -- the value of the specified size with name typeV and expand an
138 -- assignment statement to initialze this value.
140 elsif Is_Access_Type (Ent) then
141 V := Make_Defining_Identifier (Loc,
142 New_External_Name (Chars (Ent), 'V'));
145 Make_Object_Declaration (Loc,
146 Defining_Identifier => V,
148 New_Reference_To (RTE (RE_Storage_Offset), Loc),
150 Convert_To (RTE (RE_Storage_Offset), Expression (N))));
152 Set_Storage_Size_Variable (Ent, Entity_Id (V));
155 -- Other attributes require no expansion
162 end Expand_N_Attribute_Definition_Clause;
164 -------------------------------------
165 -- Expand_External_Tag_Definition --
166 -------------------------------------
168 procedure Expand_External_Tag_Definition (N : Node_Id) is
169 Loc : constant Source_Ptr := Sloc (N);
170 Ent : constant Entity_Id := Entity (Name (N));
171 Old_Val : constant String_Id := Strval (Expr_Value_S (Expression (N)));
176 -- For the rep clause "for x'external_tag use y" generate:
178 -- xV : constant string := y;
179 -- Set_External_Tag (x'tag, xV'Address);
180 -- Register_Tag (x'tag);
182 -- note that register_tag has been delayed up to now because
183 -- the external_tag must be set before registering.
185 -- Create a new nul terminated string if it is not already
187 if String_Length (Old_Val) > 0
188 and then Get_String_Char (Old_Val, String_Length (Old_Val)) = 0
192 Start_String (Old_Val);
193 Store_String_Char (Get_Char_Code (ASCII.NUL));
194 New_Val := End_String;
198 Make_Defining_Identifier (Loc,
199 New_External_Name (Chars (Ent), 'A'));
201 -- The generated actions must be elaborated at the subsequent
202 -- freeze point, not at the point of the attribute definition.
204 Append_Freeze_Action (Ent,
205 Make_Object_Declaration (Loc,
206 Defining_Identifier => E,
207 Constant_Present => True,
209 New_Reference_To (Standard_String, Loc),
211 Make_String_Literal (Loc, Strval => New_Val)));
213 Append_Freeze_Actions (Ent, New_List (
214 Make_Procedure_Call_Statement (Loc,
215 Name => New_Reference_To (RTE (RE_Set_External_Tag), Loc),
216 Parameter_Associations => New_List (
217 Make_Attribute_Reference (Loc,
218 Attribute_Name => Name_Tag,
219 Prefix => New_Occurrence_Of (Ent, Loc)),
221 Make_Attribute_Reference (Loc,
222 Attribute_Name => Name_Address,
223 Prefix => New_Occurrence_Of (E, Loc)))),
225 Make_Procedure_Call_Statement (Loc,
226 Name => New_Reference_To (RTE (RE_Register_Tag), Loc),
227 Parameter_Associations => New_List (
228 Make_Attribute_Reference (Loc,
229 Attribute_Name => Name_Tag,
230 Prefix => New_Occurrence_Of (Ent, Loc))))));
231 end Expand_External_Tag_Definition;
233 ----------------------------
234 -- Expand_N_Freeze_Entity --
235 ----------------------------
237 procedure Expand_N_Freeze_Entity (N : Node_Id) is
238 E : constant Entity_Id := Entity (N);
241 In_Other_Scope : Boolean;
242 In_Outer_Scope : Boolean;
244 Delete : Boolean := False;
247 -- Processing for objects with address clauses
249 if Is_Object (E) and then Present (Address_Clause (E)) then
250 Apply_Address_Clause_Check (E, N);
253 -- Only other items requiring any front end action are types and
256 elsif not Is_Type (E) and then not Is_Subprogram (E) then
260 -- Here E is a type or a subprogram
262 E_Scope := Scope (E);
264 -- This is an error protection against previous errors
270 -- If we are freezing entities defined in protected types, they belong
271 -- in the enclosing scope, given that the original type has been
272 -- expanded away. The same is true for entities in task types, in
273 -- particular the parameter records of entries (Entities in bodies are
274 -- all frozen within the body). If we are in the task body, this is a
277 if Ekind (E_Scope) = E_Protected_Type
278 or else (Ekind (E_Scope) = E_Task_Type
279 and then not Has_Completion (E_Scope))
281 E_Scope := Scope (E_Scope);
285 while S /= Standard_Standard and then S /= E_Scope loop
289 In_Other_Scope := not (S = E_Scope);
290 In_Outer_Scope := (not In_Other_Scope) and then (S /= Current_Scope);
292 -- If the entity being frozen is defined in a scope that is not
293 -- currently on the scope stack, we must establish the proper
294 -- visibility before freezing the entity and related subprograms.
296 if In_Other_Scope then
298 Install_Visible_Declarations (E_Scope);
300 if Ekind (E_Scope) = E_Package or else
301 Ekind (E_Scope) = E_Generic_Package or else
302 Is_Protected_Type (E_Scope) or else
303 Is_Task_Type (E_Scope)
305 Install_Private_Declarations (E_Scope);
308 -- If the entity is in an outer scope, then that scope needs to
309 -- temporarily become the current scope so that operations created
310 -- during type freezing will be declared in the right scope and
311 -- can properly override any corresponding inherited operations.
313 elsif In_Outer_Scope then
317 -- If type, freeze the type
320 Delete := Freeze_Type (N);
322 -- And for enumeration type, build the enumeration tables
324 if Is_Enumeration_Type (E) then
325 Build_Enumeration_Image_Tables (E, N);
327 elsif Is_Tagged_Type (E)
328 and then Is_First_Subtype (E)
330 -- Check for a definition of External_Tag, whose expansion must
331 -- be delayed until the dispatch table is built. The clause
332 -- is considered only if it applies to this specific tagged
333 -- type, as opposed to one of its ancestors.
336 Def : constant Node_Id :=
337 Get_Attribute_Definition_Clause
338 (E, Attribute_External_Tag);
341 if Present (Def) and then Entity (Name (Def)) = E then
342 Expand_External_Tag_Definition (Def);
347 -- If subprogram, freeze the subprogram
349 elsif Is_Subprogram (E) then
350 Freeze_Subprogram (N);
352 -- Ada 2005 (AI-251): Remove the freezing node associated with the
353 -- entities internally used by the frontend to register primitives
354 -- covering abstract interfaces. The call to Freeze_Subprogram has
355 -- already expanded the code that fills the corresponding entry in
356 -- its secondary dispatch table and therefore the code generator
357 -- has nothing else to do with this freezing node.
359 Delete := Present (Abstract_Interface_Alias (E));
362 -- Analyze actions generated by freezing. The init_proc contains source
363 -- expressions that may raise Constraint_Error, and the assignment
364 -- procedure for complex types needs checks on individual component
365 -- assignments, but all other freezing actions should be compiled with
368 if Present (Actions (N)) then
369 Decl := First (Actions (N));
370 while Present (Decl) loop
371 if Nkind (Decl) = N_Subprogram_Body
372 and then (Is_Init_Proc (Defining_Entity (Decl))
374 Chars (Defining_Entity (Decl)) = Name_uAssign)
378 -- A subprogram body created for a renaming_as_body completes
379 -- a previous declaration, which may be in a different scope.
380 -- Establish the proper scope before analysis.
382 elsif Nkind (Decl) = N_Subprogram_Body
383 and then Present (Corresponding_Spec (Decl))
384 and then Scope (Corresponding_Spec (Decl)) /= Current_Scope
386 New_Scope (Scope (Corresponding_Spec (Decl)));
387 Analyze (Decl, Suppress => All_Checks);
391 Analyze (Decl, Suppress => All_Checks);
398 -- If we are to delete this N_Freeze_Entity, do so by rewriting so that
399 -- a loop on all nodes being inserted will work propertly.
402 Rewrite (N, Make_Null_Statement (Sloc (N)));
405 if In_Other_Scope then
406 if Ekind (Current_Scope) = E_Package then
407 End_Package_Scope (E_Scope);
412 elsif In_Outer_Scope then
415 end Expand_N_Freeze_Entity;
417 -------------------------------------------
418 -- Expand_N_Record_Representation_Clause --
419 -------------------------------------------
421 -- The only expansion required is for the case of a mod clause present,
422 -- which is removed, and translated into an alignment representation
423 -- clause inserted immediately after the record rep clause with any
424 -- initial pragmas inserted at the start of the component clause list.
426 procedure Expand_N_Record_Representation_Clause (N : Node_Id) is
427 Loc : constant Source_Ptr := Sloc (N);
428 Rectype : constant Entity_Id := Entity (Identifier (N));
435 if Present (Mod_Clause (N)) then
436 Mod_Val := Expr_Value (Expression (Mod_Clause (N)));
437 Citems := Pragmas_Before (Mod_Clause (N));
439 if Present (Citems) then
440 Append_List_To (Citems, Component_Clauses (N));
441 Set_Component_Clauses (N, Citems);
445 Make_Attribute_Definition_Clause (Loc,
446 Name => New_Reference_To (Base_Type (Rectype), Loc),
447 Chars => Name_Alignment,
448 Expression => Make_Integer_Literal (Loc, Mod_Val));
450 Set_From_At_Mod (AtM_Nod);
451 Insert_After (N, AtM_Nod);
452 Set_Mod_Clause (N, Empty);
455 -- If the record representation clause has no components, then
456 -- completely remove it. Note that we also have to remove
457 -- ourself from the Rep Item list.
459 if Is_Empty_List (Component_Clauses (N)) then
460 if First_Rep_Item (Rectype) = N then
461 Set_First_Rep_Item (Rectype, Next_Rep_Item (N));
463 Repitem := First_Rep_Item (Rectype);
464 while Present (Next_Rep_Item (Repitem)) loop
465 if Next_Rep_Item (Repitem) = N then
466 Set_Next_Rep_Item (Repitem, Next_Rep_Item (N));
470 Next_Rep_Item (Repitem);
475 Make_Null_Statement (Loc));
477 end Expand_N_Record_Representation_Clause;