1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- I N T E R F A C E S . C P P --
9 -- Copyright (C) 1992-2005, 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 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 with Ada.Tags; use Ada.Tags;
35 with System; use System;
36 with System.Storage_Elements; use System.Storage_Elements;
38 package body Interfaces.CPP is
40 -- Structure of the Dispatch Table
42 -- +-----------------------+
44 -- +-----------------------+
45 -- | Typeinfo_Ptr/TSD_Ptr |----> Type Specific Data
46 -- Tag ---> +-----------------------+ +-------------------+
47 -- | table of | | inheritance depth |
48 -- : primitive ops : +-------------------+
49 -- | pointers | | expanded name |
50 -- +-----------------------+ +-------------------+
52 -- +-------------------+
53 -- | Hash table link |
54 -- +-------------------+
55 -- | Remotely Callable |
56 -- +-------------------+
57 -- | Rec Ctrler offset |
58 -- +-------------------+
62 -- +-------------------+
64 -- The declarations below need (extensive) comments ???
66 subtype Cstring is String (Positive);
67 type Cstring_Ptr is access all Cstring;
68 type Tag_Table is array (Natural range <>) of Vtable_Ptr;
69 pragma Suppress_Initialization (Tag_Table);
71 type Type_Specific_Data is record
73 Expanded_Name : Cstring_Ptr;
74 External_Tag : Cstring_Ptr;
76 Ancestor_Tags : Tag_Table (Natural);
79 type Vtable_Entry is record
83 type Vtable_Entry_Array is array (Positive range <>) of Vtable_Entry;
86 -- Offset_To_Top : Integer;
87 -- Typeinfo_Ptr : System.Address; -- TSD is currently also here???
88 Prims_Ptr : Vtable_Entry_Array (Positive);
90 -- Note: See comment in a-tags.adb explaining why the components
91 -- Offset_To_Top and Typeinfo_Ptr have been commented out.
92 -- -----------------------------------------------------------------------
93 -- The size of the Prims_Ptr array actually depends on the tagged type to
94 -- which it applies. For each tagged type, the expander computes the
95 -- actual array size, allocates the Dispatch_Table record accordingly, and
96 -- generates code that displaces the base of the record after the
97 -- Typeinfo_Ptr component. For this reason the first two components have
98 -- been commented in the previous declaration. The access to these
99 -- components is done by means of local functions.
101 ---------------------------
102 -- Unchecked Conversions --
103 ---------------------------
105 type Int_Ptr is access Integer;
107 function To_Int_Ptr is
108 new Unchecked_Conversion (System.Address, Int_Ptr);
110 function To_Cstring_Ptr is
111 new Unchecked_Conversion (Address, Cstring_Ptr);
113 function To_Address is
114 new Unchecked_Conversion (Cstring_Ptr, Address);
116 -----------------------
117 -- Local Subprograms --
118 -----------------------
120 function Length (Str : Cstring_Ptr) return Natural;
121 -- Length of string represented by the given pointer (treating the string
122 -- as a C-style string, which is Nul terminated).
124 function Offset_To_Top (T : Vtable_Ptr) return Integer;
125 -- Returns the current value of the offset_to_top component available in
126 -- the prologue of the dispatch table.
128 function Typeinfo_Ptr (T : Vtable_Ptr) return System.Address;
129 -- Returns the current value of the typeinfo_ptr component available in
130 -- the prologue of the dispatch table.
132 pragma Unreferenced (Offset_To_Top);
133 pragma Unreferenced (Typeinfo_Ptr);
134 -- These functions will be used for full compatibility with the C++ ABI
136 -----------------------
137 -- CPP_CW_Membership --
138 -----------------------
140 function CPP_CW_Membership
141 (Obj_Tag : Vtable_Ptr;
142 Typ_Tag : Vtable_Ptr) return Boolean
144 Pos : constant Integer := TSD (Obj_Tag).Idepth - TSD (Typ_Tag).Idepth;
146 return Pos >= 0 and then TSD (Obj_Tag).Ancestor_Tags (Pos) = Typ_Tag;
147 end CPP_CW_Membership;
149 --------------------------
150 -- CPP_Get_External_Tag --
151 --------------------------
153 function CPP_Get_External_Tag (T : Vtable_Ptr) return Address is
155 return To_Address (TSD (T).External_Tag);
156 end CPP_Get_External_Tag;
158 -------------------------
159 -- CPP_Get_Prim_Op_Address --
160 -------------------------
162 function CPP_Get_Prim_Op_Address
164 Position : Positive) return Address
167 return T.Prims_Ptr (Position).Pfn;
168 end CPP_Get_Prim_Op_Address;
170 -----------------------
171 -- CPP_Get_RC_Offset --
172 -----------------------
174 function CPP_Get_RC_Offset (T : Vtable_Ptr) return SSE.Storage_Offset is
175 pragma Warnings (Off, T);
178 end CPP_Get_RC_Offset;
180 -------------------------------
181 -- CPP_Get_Remotely_Callable --
182 -------------------------------
184 function CPP_Get_Remotely_Callable (T : Vtable_Ptr) return Boolean is
185 pragma Warnings (Off, T);
188 end CPP_Get_Remotely_Callable;
194 function CPP_Get_TSD (T : Vtable_Ptr) return Address is
195 use type System.Storage_Elements.Storage_Offset;
196 TSD_Ptr : constant Addr_Ptr :=
197 To_Addr_Ptr (To_Address (T) - CPP_DT_Typeinfo_Ptr_Size);
206 procedure CPP_Inherit_DT
209 Entry_Count : Natural)
212 if Old_T /= null then
213 New_T.Prims_Ptr (1 .. Entry_Count)
214 := Old_T.Prims_Ptr (1 .. Entry_Count);
218 ---------------------
219 -- CPP_Inherit_TSD --
220 ---------------------
222 procedure CPP_Inherit_TSD
224 New_Tag : Vtable_Ptr)
226 Old_TSD_Ptr : constant Type_Specific_Data_Ptr :=
227 To_Type_Specific_Data_Ptr (Old_TSD);
229 New_TSD_Ptr : constant Type_Specific_Data_Ptr :=
233 if Old_TSD_Ptr /= null then
234 New_TSD_Ptr.Idepth := Old_TSD_Ptr.Idepth + 1;
235 New_TSD_Ptr.Ancestor_Tags (1 .. New_TSD_Ptr.Idepth) :=
236 Old_TSD_Ptr.Ancestor_Tags (0 .. Old_TSD_Ptr.Idepth);
238 New_TSD_Ptr.Idepth := 0;
241 New_TSD_Ptr.Ancestor_Tags (0) := New_Tag;
244 ---------------------------
245 -- CPP_Set_Expanded_Name --
246 ---------------------------
248 procedure CPP_Set_Expanded_Name (T : Vtable_Ptr; Value : Address) is
250 TSD (T).Expanded_Name := To_Cstring_Ptr (Value);
251 end CPP_Set_Expanded_Name;
253 --------------------------
254 -- CPP_Set_External_Tag --
255 --------------------------
257 procedure CPP_Set_External_Tag (T : Vtable_Ptr; Value : Address) is
259 TSD (T).External_Tag := To_Cstring_Ptr (Value);
260 end CPP_Set_External_Tag;
262 -----------------------------
263 -- CPP_Set_Prim_Op_Address --
264 -----------------------------
266 procedure CPP_Set_Prim_Op_Address
272 T.Prims_Ptr (Position).Pfn := Value;
273 end CPP_Set_Prim_Op_Address;
275 -----------------------
276 -- CPP_Set_RC_Offset --
277 -----------------------
279 procedure CPP_Set_RC_Offset (T : Vtable_Ptr; Value : SSE.Storage_Offset) is
280 pragma Warnings (Off, T);
281 pragma Warnings (Off, Value);
284 end CPP_Set_RC_Offset;
286 -------------------------------
287 -- CPP_Set_Remotely_Callable --
288 -------------------------------
290 procedure CPP_Set_Remotely_Callable (T : Vtable_Ptr; Value : Boolean) is
291 pragma Warnings (Off, T);
292 pragma Warnings (Off, Value);
295 end CPP_Set_Remotely_Callable;
301 procedure CPP_Set_TSD (T : Vtable_Ptr; Value : Address) is
302 use type System.Storage_Elements.Storage_Offset;
303 TSD_Ptr : constant Addr_Ptr :=
304 To_Addr_Ptr (To_Address (T) - CPP_DT_Typeinfo_Ptr_Size);
306 TSD_Ptr.all := Value;
313 function Displaced_This
314 (Current_This : System.Address;
317 return System.Address
319 pragma Warnings (Off, Vptr);
320 pragma Warnings (Off, Position);
325 -- why is the following here commented out ???
326 -- + Storage_Offset (Vptr.Prims_Ptr (Position).Delta1);
333 function Expanded_Name (T : Vtable_Ptr) return String is
334 Result : constant Cstring_Ptr := TSD (T).Expanded_Name;
336 return Result (1 .. Length (Result));
343 function External_Tag (T : Vtable_Ptr) return String is
344 Result : constant Cstring_Ptr := TSD (T).External_Tag;
346 return Result (1 .. Length (Result));
353 function Length (Str : Cstring_Ptr) return Natural is
357 while Str (Len) /= ASCII.Nul loop
368 function Offset_To_Top (T : Vtable_Ptr) return Integer is
369 use type System.Storage_Elements.Storage_Offset;
371 TSD_Ptr : constant Int_Ptr
372 := To_Int_Ptr (To_Address (T) - CPP_DT_Prologue_Size);
381 function Typeinfo_Ptr (T : Vtable_Ptr) return System.Address is
382 use type System.Storage_Elements.Storage_Offset;
383 TSD_Ptr : constant Addr_Ptr :=
384 To_Addr_Ptr (To_Address (T) - CPP_DT_Typeinfo_Ptr_Size);
393 function TSD (T : Vtable_Ptr) return Type_Specific_Data_Ptr is
395 return To_Type_Specific_Data_Ptr (CPP_Get_TSD (T));