1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2003, 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);
98 if Nkind (Decl) = N_Object_Declaration
99 and then Present (Expression (Decl))
101 not Comes_From_Source (Original_Node (Expression (Decl)))
103 Set_Expression (Decl, Empty);
111 when Attribute_Alignment =>
113 -- As required by Gigi, we guarantee that the operand is an
114 -- integer literal (this simplifies things in Gigi).
116 if Nkind (Exp) /= N_Integer_Literal then
118 (Exp, Make_Integer_Literal (Loc, Expr_Value (Exp)));
125 when Attribute_Storage_Size =>
127 -- If the type is a task type, then assign the value of the
128 -- storage size to the Size variable associated with the task.
129 -- task_typeZ := expression
131 if Ekind (Ent) = E_Task_Type then
133 Make_Assignment_Statement (Loc,
134 Name => New_Reference_To (Storage_Size_Variable (Ent), Loc),
136 Convert_To (RTE (RE_Size_Type), Expression (N))));
138 -- For Storage_Size for an access type, create a variable to hold
139 -- the value of the specified size with name typeV and expand an
140 -- assignment statement to initialze this value.
142 elsif Is_Access_Type (Ent) then
144 V := Make_Defining_Identifier (Loc,
145 New_External_Name (Chars (Ent), 'V'));
148 Make_Object_Declaration (Loc,
149 Defining_Identifier => V,
151 New_Reference_To (RTE (RE_Storage_Offset), Loc),
153 Convert_To (RTE (RE_Storage_Offset), Expression (N))));
155 Set_Storage_Size_Variable (Ent, Entity_Id (V));
158 -- Other attributes require no expansion
165 end Expand_N_Attribute_Definition_Clause;
167 -------------------------------------
168 -- Expand_External_Tag_Definition --
169 -------------------------------------
171 procedure Expand_External_Tag_Definition (N : Node_Id) is
172 Loc : constant Source_Ptr := Sloc (N);
173 Ent : constant Entity_Id := Entity (Name (N));
174 Old_Val : constant String_Id := Strval (Expr_Value_S (Expression (N)));
179 -- For the rep clause "for x'external_tag use y" generate:
181 -- xV : constant string := y;
182 -- Set_External_Tag (x'tag, xV'Address);
183 -- Register_Tag (x'tag);
185 -- note that register_tag has been delayed up to now because
186 -- the external_tag must be set before registering.
188 -- Create a new nul terminated string if it is not already
190 if String_Length (Old_Val) > 0
191 and then Get_String_Char (Old_Val, String_Length (Old_Val)) = 0
195 Start_String (Old_Val);
196 Store_String_Char (Get_Char_Code (ASCII.NUL));
197 New_Val := End_String;
201 Make_Defining_Identifier (Loc,
202 New_External_Name (Chars (Ent), 'A'));
204 -- The generated actions must be elaborated at the subsequent
205 -- freeze point, not at the point of the attribute definition.
207 Append_Freeze_Action (Ent,
208 Make_Object_Declaration (Loc,
209 Defining_Identifier => E,
210 Constant_Present => True,
212 New_Reference_To (Standard_String, Loc),
214 Make_String_Literal (Loc, Strval => New_Val)));
216 Append_Freeze_Actions (Ent, New_List (
217 Make_Procedure_Call_Statement (Loc,
218 Name => New_Reference_To (RTE (RE_Set_External_Tag), Loc),
219 Parameter_Associations => New_List (
220 Make_Attribute_Reference (Loc,
221 Attribute_Name => Name_Tag,
222 Prefix => New_Occurrence_Of (Ent, Loc)),
224 Make_Attribute_Reference (Loc,
225 Attribute_Name => Name_Address,
226 Prefix => New_Occurrence_Of (E, Loc)))),
228 Make_Procedure_Call_Statement (Loc,
229 Name => New_Reference_To (RTE (RE_Register_Tag), Loc),
230 Parameter_Associations => New_List (
231 Make_Attribute_Reference (Loc,
232 Attribute_Name => Name_Tag,
233 Prefix => New_Occurrence_Of (Ent, Loc))))));
234 end Expand_External_Tag_Definition;
236 ----------------------------
237 -- Expand_N_Freeze_Entity --
238 ----------------------------
240 procedure Expand_N_Freeze_Entity (N : Node_Id) is
241 E : constant Entity_Id := Entity (N);
244 In_Other_Scope : Boolean;
245 In_Outer_Scope : Boolean;
249 -- For object, with address clause, check alignment is OK
251 if Is_Object (E) then
252 Apply_Alignment_Check (E, N);
254 -- Only other items requiring any front end action are
255 -- types and subprograms.
257 elsif not Is_Type (E) and then not Is_Subprogram (E) then
261 -- Here E is a type or a subprogram
263 E_Scope := Scope (E);
265 -- This is an error protection against previous errors
271 -- If we are freezing entities defined in protected types, they
272 -- belong in the enclosing scope, given that the original type
273 -- has been expanded away. The same is true for entities in task types,
274 -- in particular the parameter records of entries (Entities in bodies
275 -- are all frozen within the body). If we are in the task body, this
276 -- is a proper scope.
278 if Ekind (E_Scope) = E_Protected_Type
279 or else (Ekind (E_Scope) = E_Task_Type
280 and then not Has_Completion (E_Scope))
282 E_Scope := Scope (E_Scope);
286 while S /= Standard_Standard and then S /= E_Scope loop
290 In_Other_Scope := not (S = E_Scope);
291 In_Outer_Scope := (not In_Other_Scope) and then (S /= Current_Scope);
293 -- If the entity being frozen is defined in a scope that is not
294 -- currently on the scope stack, we must establish the proper
295 -- visibility before freezing the entity and related subprograms.
297 if In_Other_Scope then
299 Install_Visible_Declarations (E_Scope);
301 if Ekind (E_Scope) = E_Package or else
302 Ekind (E_Scope) = E_Generic_Package or else
303 Is_Protected_Type (E_Scope) or else
304 Is_Task_Type (E_Scope)
306 Install_Private_Declarations (E_Scope);
309 -- If the entity is in an outer scope, then that scope needs to
310 -- temporarily become the current scope so that operations created
311 -- during type freezing will be declared in the right scope and
312 -- can properly override any corresponding inherited operations.
314 elsif In_Outer_Scope then
318 -- If type, freeze the type
323 -- And for enumeration type, build the enumeration tables
325 if Is_Enumeration_Type (E) then
326 Build_Enumeration_Image_Tables (E, N);
328 elsif Is_Tagged_Type (E)
329 and then Is_First_Subtype (E)
331 -- Check for a definition of External_Tag, whose expansion must
332 -- be delayed until the dispatch table is built. The clause
333 -- is considered only if it applies to this specific tagged
334 -- type, as opposed to one of its ancestors.
337 Def : constant Node_Id :=
338 Get_Attribute_Definition_Clause
339 (E, Attribute_External_Tag);
342 if Present (Def) and then Entity (Name (Def)) = E then
343 Expand_External_Tag_Definition (Def);
348 -- If subprogram, freeze the subprogram
350 elsif Is_Subprogram (E) then
351 Freeze_Subprogram (N);
354 -- Analyze actions generated by freezing. The init_proc contains
355 -- source expressions that may raise constraint_error, and the
356 -- assignment procedure for complex types needs checks on individual
357 -- component assignments, but all other freezing actions should be
358 -- compiled with all checks off.
360 if Present (Actions (N)) then
361 Decl := First (Actions (N));
363 while Present (Decl) loop
365 if Nkind (Decl) = N_Subprogram_Body
366 and then (Is_Init_Proc (Defining_Entity (Decl))
368 Chars (Defining_Entity (Decl)) = Name_uAssign)
372 -- A subprogram body created for a renaming_as_body completes
373 -- a previous declaration, which may be in a different scope.
374 -- Establish the proper scope before analysis.
376 elsif Nkind (Decl) = N_Subprogram_Body
377 and then Present (Corresponding_Spec (Decl))
378 and then Scope (Corresponding_Spec (Decl)) /= Current_Scope
380 New_Scope (Scope (Corresponding_Spec (Decl)));
381 Analyze (Decl, Suppress => All_Checks);
385 Analyze (Decl, Suppress => All_Checks);
392 if In_Other_Scope then
393 if Ekind (Current_Scope) = E_Package then
394 End_Package_Scope (E_Scope);
399 elsif In_Outer_Scope then
402 end Expand_N_Freeze_Entity;
404 -------------------------------------------
405 -- Expand_N_Record_Representation_Clause --
406 -------------------------------------------
408 -- The only expansion required is for the case of a mod clause present,
409 -- which is removed, and translated into an alignment representation
410 -- clause inserted immediately after the record rep clause with any
411 -- initial pragmas inserted at the start of the component clause list.
413 procedure Expand_N_Record_Representation_Clause (N : Node_Id) is
414 Loc : constant Source_Ptr := Sloc (N);
415 Rectype : constant Entity_Id := Entity (Identifier (N));
422 if Present (Mod_Clause (N)) then
423 Mod_Val := Expr_Value (Expression (Mod_Clause (N)));
424 Citems := Pragmas_Before (Mod_Clause (N));
426 if Present (Citems) then
427 Append_List_To (Citems, Component_Clauses (N));
428 Set_Component_Clauses (N, Citems);
432 Make_Attribute_Definition_Clause (Loc,
433 Name => New_Reference_To (Base_Type (Rectype), Loc),
434 Chars => Name_Alignment,
435 Expression => Make_Integer_Literal (Loc, Mod_Val));
437 Set_From_At_Mod (AtM_Nod);
438 Insert_After (N, AtM_Nod);
439 Set_Mod_Clause (N, Empty);
442 -- If the record representation clause has no components, then
443 -- completely remove it. Note that we also have to remove
444 -- ourself from the Rep Item list.
446 if Is_Empty_List (Component_Clauses (N)) then
447 if First_Rep_Item (Rectype) = N then
448 Set_First_Rep_Item (Rectype, Next_Rep_Item (N));
450 Repitem := First_Rep_Item (Rectype);
451 while Present (Next_Rep_Item (Repitem)) loop
452 if Next_Rep_Item (Repitem) = N then
453 Set_Next_Rep_Item (Repitem, Next_Rep_Item (N));
457 Next_Rep_Item (Repitem);
462 Make_Null_Statement (Loc));
464 end Expand_N_Record_Representation_Clause;