gcc/ada/i-cpp.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUNTIME COMPONENTS                          --
   4 --                                                                          --
   5 --                       I N T E R F A C E S . C P P                        --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                            $Revision: 1.12 $
  10 --                                                                          --
  11 --          Copyright (C) 1992-2000, Free Software Foundation, Inc.         --
  12 --                                                                          --
  13 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  14 -- terms of the  GNU General Public License as published  by the Free Soft- --
  15 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  16 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  17 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  18 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  19 -- for  more details.  You should have  received  a copy of the GNU General --
  20 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  21 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  22 -- MA 02111-1307, USA.                                                      --
  23 --                                                                          --
  24 -- As a special exception,  if other files  instantiate  generics from this --
  25 -- unit, or you link  this unit with other files  to produce an executable, --
  26 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  27 -- covered  by the  GNU  General  Public  License.  This exception does not --
  28 -- however invalidate  any other reasons why  the executable file  might be --
  29 -- covered by the  GNU Public License.                                      --
  30 --                                                                          --
  31 -- GNAT was originally developed  by the GNAT team at  New York University. --
  32 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 --  Definitions for interfacing to C++ classes
  37
  38 with System;
  39 with System.Storage_Elements;
  40
  41 package Interfaces.CPP is
  42
  43    package S   renames System;
  44    package SSE renames System.Storage_Elements;
  45
  46    --  This package corresponds to Ada.Tags but applied to tagged types
  47    --  which are 'imported' from C++ and correspond to exactly to a C++
  48    --  Class.  GNAT doesn't know about the structure od the C++ dispatch
  49    --  table (Vtable) but always access it through the procedural interface
  50    --  defined below, thus the implementation of this package (the body) can
  51    --  be customized to another C++ compiler without any change in the
  52    --  compiler code itself as long as this procedural interface is
  53    --  respected. Note that Ada.Tags defines a very similar procedural
  54    --  interface to the regular Ada Dispatch Table.
  55
  56    type Vtable_Ptr is private;
  57
  58    function Expanded_Name (T : Vtable_Ptr) return String;
  59    function External_Tag  (T : Vtable_Ptr) return String;
  60
  61 private
  62
  63    procedure CPP_Set_Prim_Op_Address
  64      (T        : Vtable_Ptr;
  65       Position : Positive;
  66       Value    : S.Address);
  67    --  Given a pointer to a dispatch Table (T) and a position in the
  68    --  dispatch Table put the address of the virtual function in it
  69    --  (used for overriding)
  70
  71    function CPP_Get_Prim_Op_Address
  72      (T        : Vtable_Ptr;
  73       Position : Positive)
  74       return     S.Address;
  75    --  Given a pointer to a dispatch Table (T) and a position in the DT
  76    --  this function returns the address of the virtual function stored
  77    --  in it (used for dispatching calls)
  78
  79    procedure CPP_Set_Inheritance_Depth
  80      (T     : Vtable_Ptr;
  81       Value : Natural);
  82    --  Given a pointer to a dispatch Table, stores the value representing
  83    --  the depth in the inheritance tree. Used during elaboration of the
  84    --  tagged type.
  85
  86    function CPP_Get_Inheritance_Depth (T : Vtable_Ptr) return Natural;
  87    --  Given a pointer to a dispatch Table, retreives the value representing
  88    --  the depth in the inheritance tree. Used for membership.
  89
  90    procedure CPP_Set_TSD (T : Vtable_Ptr; Value : S.Address);
  91    --  Given a pointer T to a dispatch Table, stores the address of the
  92    --  record containing the Type Specific Data generated by GNAT
  93
  94    function CPP_Get_TSD (T : Vtable_Ptr) return S.Address;
  95    --  Given a pointer T to a dispatch Table, retreives the address of the
  96    --  record containing the Type Specific Data generated by GNAT
  97
  98    CPP_DT_Prologue_Size : constant SSE.Storage_Count :=
  99                             SSE.Storage_Count
 100                               (2 * (Standard'Address_Size / S.Storage_Unit));
 101    --  Size of the first part of the dispatch table
 102
 103    CPP_DT_Entry_Size : constant SSE.Storage_Count :=
 104                          SSE.Storage_Count
 105                            (1 * (Standard'Address_Size / S.Storage_Unit));
 106    --  Size of each primitive operation entry in the Dispatch Table.
 107
 108    CPP_TSD_Prologue_Size : constant SSE.Storage_Count :=
 109                              SSE.Storage_Count
 110                                (4 * (Standard'Address_Size / S.Storage_Unit));
 111    --  Size of the first part of the type specific data
 112
 113    CPP_TSD_Entry_Size : constant SSE.Storage_Count :=
 114                           SSE.Storage_Count
 115                             (Standard'Address_Size / S.Storage_Unit);
 116    --  Size of each ancestor tag entry in the TSD
 117
 118    procedure CPP_Inherit_DT
 119     (Old_T       : Vtable_Ptr;
 120      New_T       : Vtable_Ptr;
 121      Entry_Count : Natural);
 122    --  Entry point used to initialize the DT of a type knowing the
 123    --  tag of the direct ancestor and the number of primitive ops that are
 124    --  inherited (Entry_Count).
 125
 126    procedure CPP_Inherit_TSD
 127      (Old_TSD : S.Address;
 128       New_Tag : Vtable_Ptr);
 129    --  Entry point used to initialize the TSD of a type knowing the
 130    --  TSD of the direct ancestor.
 131
 132    function CPP_CW_Membership (Obj_Tag, Typ_Tag : Vtable_Ptr) return Boolean;
 133    --  Given the tag of an object and the tag associated to a type, return
 134    --  true if Obj is in Typ'Class.
 135
 136    procedure CPP_Set_External_Tag (T : Vtable_Ptr; Value : S.Address);
 137    --  Set the address of the string containing the external tag
 138    --  in the Dispatch table
 139
 140    function CPP_Get_External_Tag (T : Vtable_Ptr) return S.Address;
 141    --  Retrieve the address of a null terminated string containing
 142    --  the external name
 143
 144    procedure CPP_Set_Expanded_Name (T : Vtable_Ptr; Value : S.Address);
 145    --  Set the address of the string containing the expanded name
 146    --  in the Dispatch table
 147
 148    function CPP_Get_Expanded_Name (T : Vtable_Ptr) return S.Address;
 149    --  Retrieve the address of a null terminated string containing
 150    --  the expanded name
 151
 152    procedure CPP_Set_Remotely_Callable (T : Vtable_Ptr; Value : Boolean);
 153    --  Since the notions of spec/body distinction and categorized packages
 154    --  do not exist in C, this procedure will do nothing
 155
 156    function CPP_Get_Remotely_Callable (T : Vtable_Ptr) return Boolean;
 157    --  This function will always return True for the reason explained above
 158
 159    procedure CPP_Set_RC_Offset (T : Vtable_Ptr; Value : SSE.Storage_Offset);
 160    --  Sets the Offset of the implicit record controller when the object
 161    --  has controlled components. Set to O otherwise.
 162
 163    function CPP_Get_RC_Offset (T : Vtable_Ptr) return SSE.Storage_Offset;
 164    --  Return the Offset of the implicit record controller when the object
 165    --  has controlled components. O otherwise.
 166
 167    function Displaced_This
 168     (Current_This : S.Address;
 169      Vptr         : Vtable_Ptr;
 170      Position     : Positive)
 171      return         S.Address;
 172    --  Compute the displacement on the "this" pointer in order to be
 173    --  compatible with MI.
 174    --  (used for virtual function calls)
 175
 176    type Vtable;
 177    type Vtable_Ptr is access all Vtable;
 178
 179    pragma Inline (CPP_Set_Prim_Op_Address);
 180    pragma Inline (CPP_Get_Prim_Op_Address);
 181    pragma Inline (CPP_Set_Inheritance_Depth);
 182    pragma Inline (CPP_Get_Inheritance_Depth);
 183    pragma Inline (CPP_Set_TSD);
 184    pragma Inline (CPP_Get_TSD);
 185    pragma Inline (CPP_Inherit_DT);
 186    pragma Inline (CPP_CW_Membership);
 187    pragma Inline (CPP_Set_External_Tag);
 188    pragma Inline (CPP_Get_External_Tag);
 189    pragma Inline (CPP_Set_Expanded_Name);
 190    pragma Inline (CPP_Get_Expanded_Name);
 191    pragma Inline (CPP_Set_Remotely_Callable);
 192    pragma Inline (CPP_Get_Remotely_Callable);
 193    pragma Inline (Displaced_This);
 194
 195 end Interfaces.CPP;