1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2004, 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, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, 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
85 -- the source program, then it is an artifact of our
86 -- expansion, and we suppress it. The case we are most
87 -- concerned about here is the initialization of a packed
88 -- array to all false, which seems inappropriate for a
89 -- variable to which an address clause is applied. The
90 -- expression may itself have been rewritten if the type is a
91 -- packed array, so we need to examine whether the original
92 -- node is in the source.
95 Decl : constant Node_Id := Declaration_Node (Ent);
97 if Nkind (Decl) = N_Object_Declaration
98 and then Present (Expression (Decl))
100 not Comes_From_Source (Original_Node (Expression (Decl)))
102 Set_Expression (Decl, Empty);
110 when Attribute_Alignment =>
112 -- As required by Gigi, we guarantee that the operand is an
113 -- integer literal (this simplifies things in Gigi).
115 if Nkind (Exp) /= N_Integer_Literal then
117 (Exp, Make_Integer_Literal (Loc, Expr_Value (Exp)));
124 when Attribute_Storage_Size =>
126 -- If the type is a task type, then assign the value of the
127 -- storage size to the Size variable associated with the task.
128 -- task_typeZ := expression
130 if Ekind (Ent) = E_Task_Type then
132 Make_Assignment_Statement (Loc,
133 Name => New_Reference_To (Storage_Size_Variable (Ent), Loc),
135 Convert_To (RTE (RE_Size_Type), Expression (N))));
137 -- For Storage_Size for an access type, create a variable to hold
138 -- the value of the specified size with name typeV and expand an
139 -- assignment statement to initialze this value.
141 elsif Is_Access_Type (Ent) then
143 V := Make_Defining_Identifier (Loc,
144 New_External_Name (Chars (Ent), 'V'));
147 Make_Object_Declaration (Loc,
148 Defining_Identifier => V,
150 New_Reference_To (RTE (RE_Storage_Offset), Loc),
152 Convert_To (RTE (RE_Storage_Offset), Expression (N))));
154 Set_Storage_Size_Variable (Ent, Entity_Id (V));
157 -- Other attributes require no expansion
164 end Expand_N_Attribute_Definition_Clause;
166 -------------------------------------
167 -- Expand_External_Tag_Definition --
168 -------------------------------------
170 procedure Expand_External_Tag_Definition (N : Node_Id) is
171 Loc : constant Source_Ptr := Sloc (N);
172 Ent : constant Entity_Id := Entity (Name (N));
173 Old_Val : constant String_Id := Strval (Expr_Value_S (Expression (N)));
178 -- For the rep clause "for x'external_tag use y" generate:
180 -- xV : constant string := y;
181 -- Set_External_Tag (x'tag, xV'Address);
182 -- Register_Tag (x'tag);
184 -- note that register_tag has been delayed up to now because
185 -- the external_tag must be set before registering.
187 -- Create a new nul terminated string if it is not already
189 if String_Length (Old_Val) > 0
190 and then Get_String_Char (Old_Val, String_Length (Old_Val)) = 0
194 Start_String (Old_Val);
195 Store_String_Char (Get_Char_Code (ASCII.NUL));
196 New_Val := End_String;
200 Make_Defining_Identifier (Loc,
201 New_External_Name (Chars (Ent), 'A'));
203 -- The generated actions must be elaborated at the subsequent
204 -- freeze point, not at the point of the attribute definition.
206 Append_Freeze_Action (Ent,
207 Make_Object_Declaration (Loc,
208 Defining_Identifier => E,
209 Constant_Present => True,
211 New_Reference_To (Standard_String, Loc),
213 Make_String_Literal (Loc, Strval => New_Val)));
215 Append_Freeze_Actions (Ent, New_List (
216 Make_Procedure_Call_Statement (Loc,
217 Name => New_Reference_To (RTE (RE_Set_External_Tag), Loc),
218 Parameter_Associations => New_List (
219 Make_Attribute_Reference (Loc,
220 Attribute_Name => Name_Tag,
221 Prefix => New_Occurrence_Of (Ent, Loc)),
223 Make_Attribute_Reference (Loc,
224 Attribute_Name => Name_Address,
225 Prefix => New_Occurrence_Of (E, Loc)))),
227 Make_Procedure_Call_Statement (Loc,
228 Name => New_Reference_To (RTE (RE_Register_Tag), Loc),
229 Parameter_Associations => New_List (
230 Make_Attribute_Reference (Loc,
231 Attribute_Name => Name_Tag,
232 Prefix => New_Occurrence_Of (Ent, Loc))))));
233 end Expand_External_Tag_Definition;
235 ----------------------------
236 -- Expand_N_Freeze_Entity --
237 ----------------------------
239 procedure Expand_N_Freeze_Entity (N : Node_Id) is
240 E : constant Entity_Id := Entity (N);
243 In_Other_Scope : Boolean;
244 In_Outer_Scope : Boolean;
248 -- For object, with address clause, check alignment is OK
250 if Is_Object (E) then
251 Apply_Alignment_Check (E, N);
253 -- Only other items requiring any front end action are
254 -- types and subprograms.
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
271 -- belong in the enclosing scope, given that the original type
272 -- has been expanded away. The same is true for entities in task types,
273 -- in particular the parameter records of entries (Entities in bodies
274 -- are all frozen within the body). If we are in the task body, this
275 -- is a proper scope.
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
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);
353 -- Analyze actions generated by freezing. The init_proc contains
354 -- source expressions that may raise constraint_error, and the
355 -- assignment procedure for complex types needs checks on individual
356 -- component assignments, but all other freezing actions should be
357 -- compiled with all checks off.
359 if Present (Actions (N)) then
360 Decl := First (Actions (N));
362 while Present (Decl) loop
364 if Nkind (Decl) = N_Subprogram_Body
365 and then (Is_Init_Proc (Defining_Entity (Decl))
367 Chars (Defining_Entity (Decl)) = Name_uAssign)
371 -- A subprogram body created for a renaming_as_body completes
372 -- a previous declaration, which may be in a different scope.
373 -- Establish the proper scope before analysis.
375 elsif Nkind (Decl) = N_Subprogram_Body
376 and then Present (Corresponding_Spec (Decl))
377 and then Scope (Corresponding_Spec (Decl)) /= Current_Scope
379 New_Scope (Scope (Corresponding_Spec (Decl)));
380 Analyze (Decl, Suppress => All_Checks);
384 Analyze (Decl, Suppress => All_Checks);
391 if In_Other_Scope then
392 if Ekind (Current_Scope) = E_Package then
393 End_Package_Scope (E_Scope);
398 elsif In_Outer_Scope then
401 end Expand_N_Freeze_Entity;
403 -------------------------------------------
404 -- Expand_N_Record_Representation_Clause --
405 -------------------------------------------
407 -- The only expansion required is for the case of a mod clause present,
408 -- which is removed, and translated into an alignment representation
409 -- clause inserted immediately after the record rep clause with any
410 -- initial pragmas inserted at the start of the component clause list.
412 procedure Expand_N_Record_Representation_Clause (N : Node_Id) is
413 Loc : constant Source_Ptr := Sloc (N);
414 Rectype : constant Entity_Id := Entity (Identifier (N));
421 if Present (Mod_Clause (N)) then
422 Mod_Val := Expr_Value (Expression (Mod_Clause (N)));
423 Citems := Pragmas_Before (Mod_Clause (N));
425 if Present (Citems) then
426 Append_List_To (Citems, Component_Clauses (N));
427 Set_Component_Clauses (N, Citems);
431 Make_Attribute_Definition_Clause (Loc,
432 Name => New_Reference_To (Base_Type (Rectype), Loc),
433 Chars => Name_Alignment,
434 Expression => Make_Integer_Literal (Loc, Mod_Val));
436 Set_From_At_Mod (AtM_Nod);
437 Insert_After (N, AtM_Nod);
438 Set_Mod_Clause (N, Empty);
441 -- If the record representation clause has no components, then
442 -- completely remove it. Note that we also have to remove
443 -- ourself from the Rep Item list.
445 if Is_Empty_List (Component_Clauses (N)) then
446 if First_Rep_Item (Rectype) = N then
447 Set_First_Rep_Item (Rectype, Next_Rep_Item (N));
449 Repitem := First_Rep_Item (Rectype);
450 while Present (Next_Rep_Item (Repitem)) loop
451 if Next_Rep_Item (Repitem) = N then
452 Set_Next_Rep_Item (Repitem, Next_Rep_Item (N));
456 Next_Rep_Item (Repitem);
461 Make_Null_Statement (Loc));
463 end Expand_N_Record_Representation_Clause;