------------------------------------------------------------------------------ -- -- -- GNAT RUNTIME COMPONENTS -- -- -- -- I N T E R F A C E S . C P P -- -- -- -- S p e c -- -- -- -- Copyright (C) 1992-2005, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- Definitions for interfacing to C++ classes -- This package corresponds to Ada.Tags but applied to tagged types which are -- are imported from C++ and correspond exactly to a C++ Class. The code that -- the GNAT front end generates does not know about the structure of the C++ -- dispatch table (Vtable) but always accesses it through the procedural -- interface defined in this package, thus the implementation of this package -- (the body) can be customized to another C++ compiler without any change in -- the compiler code itself as long as this procedural interface is respected. -- Note that Ada.Tags defines a very similar procedural interface to the -- regular Ada Dispatch Table. with System; with System.Storage_Elements; with Unchecked_Conversion; package Interfaces.CPP is type Vtable_Ptr is private; function Expanded_Name (T : Vtable_Ptr) return String; function External_Tag (T : Vtable_Ptr) return String; private package S renames System; package SSE renames System.Storage_Elements; type Vtable; type Vtable_Ptr is access all Vtable; type Type_Specific_Data; type Type_Specific_Data_Ptr is access all Type_Specific_Data; -- These subprograms are in the private part. They are never accessed -- directly except from compiler generated code, which has access to -- private components of packages via the Rtsfind interface. procedure CPP_Set_Prim_Op_Address (T : Vtable_Ptr; Position : Positive; Value : S.Address); -- Given a pointer to a dispatch Table (T) and a position in the -- dispatch Table put the address of the virtual function in it -- (used for overriding) function CPP_Get_Prim_Op_Address (T : Vtable_Ptr; Position : Positive) return S.Address; -- Given a pointer to a dispatch Table (T) and a position in the DT -- this function returns the address of the virtual function stored -- in it (used for dispatching calls) procedure CPP_Set_Inheritance_Depth (T : Vtable_Ptr; Value : Natural); -- Given a pointer to a dispatch Table, stores the value representing -- the depth in the inheritance tree. Used during elaboration of the -- tagged type. function CPP_Get_Inheritance_Depth (T : Vtable_Ptr) return Natural; -- Given a pointer to a dispatch Table, retreives the value representing -- the depth in the inheritance tree. Used for membership. procedure CPP_Set_TSD (T : Vtable_Ptr; Value : S.Address); -- Given a pointer T to a dispatch Table, stores the address of the -- record containing the Type Specific Data generated by GNAT function CPP_Get_TSD (T : Vtable_Ptr) return S.Address; -- Given a pointer T to a dispatch Table, retreives the address of the -- record containing the Type Specific Data generated by GNAT CPP_DT_Prologue_Size : constant SSE.Storage_Count := SSE.Storage_Count (2 * (Standard'Address_Size / S.Storage_Unit)); -- Size of the first part of the dispatch table CPP_DT_Typeinfo_Ptr_Size : constant SSE.Storage_Count := SSE.Storage_Count (Standard'Address_Size / System.Storage_Unit); -- Size of the Typeinfo_Ptr field of the Dispatch Table. CPP_DT_Entry_Size : constant SSE.Storage_Count := SSE.Storage_Count (1 * (Standard'Address_Size / S.Storage_Unit)); -- Size of each primitive operation entry in the Dispatch Table. CPP_TSD_Prologue_Size : constant SSE.Storage_Count := SSE.Storage_Count (4 * (Standard'Address_Size / S.Storage_Unit)); -- Size of the first part of the type specific data CPP_TSD_Entry_Size : constant SSE.Storage_Count := SSE.Storage_Count (1 * (Standard'Address_Size / S.Storage_Unit)); -- Size of each ancestor tag entry in the TSD procedure CPP_Inherit_DT (Old_T : Vtable_Ptr; New_T : Vtable_Ptr; Entry_Count : Natural); -- Entry point used to initialize the DT of a type knowing the -- tag of the direct ancestor and the number of primitive ops that are -- inherited (Entry_Count). procedure CPP_Inherit_TSD (Old_TSD : S.Address; New_Tag : Vtable_Ptr); -- Entry point used to initialize the TSD of a type knowing the -- TSD of the direct ancestor. function CPP_CW_Membership (Obj_Tag, Typ_Tag : Vtable_Ptr) return Boolean; -- Given the tag of an object and the tag associated to a type, return -- true if Obj is in Typ'Class. procedure CPP_Set_External_Tag (T : Vtable_Ptr; Value : S.Address); -- Set the address of the string containing the external tag -- in the Dispatch table function CPP_Get_External_Tag (T : Vtable_Ptr) return S.Address; -- Retrieve the address of a null terminated string containing -- the external name procedure CPP_Set_Expanded_Name (T : Vtable_Ptr; Value : S.Address); -- Set the address of the string containing the expanded name -- in the Dispatch table function CPP_Get_Expanded_Name (T : Vtable_Ptr) return S.Address; -- Retrieve the address of a null terminated string containing -- the expanded name procedure CPP_Set_Remotely_Callable (T : Vtable_Ptr; Value : Boolean); -- Since the notions of spec/body distinction and categorized packages -- do not exist in C, this procedure will do nothing function CPP_Get_Remotely_Callable (T : Vtable_Ptr) return Boolean; -- This function will always return True for the reason explained above procedure CPP_Set_RC_Offset (T : Vtable_Ptr; Value : SSE.Storage_Offset); -- Sets the Offset of the implicit record controller when the object -- has controlled components. Set to O otherwise. function CPP_Get_RC_Offset (T : Vtable_Ptr) return SSE.Storage_Offset; -- Return the Offset of the implicit record controller when the object -- has controlled components. O otherwise. function Displaced_This (Current_This : S.Address; Vptr : Vtable_Ptr; Position : Positive) return S.Address; -- Compute the displacement on the "this" pointer in order to be -- compatible with MI. -- (used for virtual function calls) function TSD (T : Vtable_Ptr) return Type_Specific_Data_Ptr; -- This function is conceptually equivalent to Get_TSD, but -- returning a Type_Specific_Data_Ptr type (rather than an Address) -- simplifies the implementation of the other subprograms. type Addr_Ptr is access System.Address; function To_Address is new Unchecked_Conversion (Vtable_Ptr, System.Address); function To_Addr_Ptr is new Unchecked_Conversion (System.Address, Addr_Ptr); function To_Type_Specific_Data_Ptr is new Unchecked_Conversion (System.Address, Type_Specific_Data_Ptr); pragma Inline (CPP_Set_Prim_Op_Address); pragma Inline (CPP_Get_Prim_Op_Address); pragma Inline (CPP_Set_Inheritance_Depth); pragma Inline (CPP_Get_Inheritance_Depth); pragma Inline (CPP_Set_TSD); pragma Inline (CPP_Get_TSD); pragma Inline (CPP_Inherit_DT); pragma Inline (CPP_CW_Membership); pragma Inline (CPP_Set_External_Tag); pragma Inline (CPP_Get_External_Tag); pragma Inline (CPP_Set_Expanded_Name); pragma Inline (CPP_Get_Expanded_Name); pragma Inline (CPP_Set_Remotely_Callable); pragma Inline (CPP_Get_Remotely_Callable); pragma Inline (Displaced_This); pragma Inline (TSD); end Interfaces.CPP;