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