------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME COMPONENTS -- -- -- -- I N T E R F A C E S . C P P -- -- -- -- B o d y -- -- -- -- 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. -- -- -- ------------------------------------------------------------------------------ with Ada.Tags; use Ada.Tags; with System; use System; with System.Storage_Elements; use System.Storage_Elements; package body Interfaces.CPP is -- Structure of the Dispatch Table -- +-----------------------+ -- | Offset_To_Top | -- +-----------------------+ -- | Typeinfo_Ptr/TSD_Ptr |----> Type Specific Data -- Tag ---> +-----------------------+ +-------------------+ -- | table of | | inheritance depth | -- : primitive ops : +-------------------+ -- | pointers | | expanded name | -- +-----------------------+ +-------------------+ -- | external tag | -- +-------------------+ -- | Hash table link | -- +-------------------+ -- | Remotely Callable | -- +-------------------+ -- | Rec Ctrler offset | -- +-------------------+ -- | table of | -- : ancestor : -- | tags | -- +-------------------+ -- The declarations below need (extensive) comments ??? subtype Cstring is String (Positive); type Cstring_Ptr is access all Cstring; type Tag_Table is array (Natural range <>) of Vtable_Ptr; pragma Suppress_Initialization (Tag_Table); type Type_Specific_Data is record Idepth : Natural; Expanded_Name : Cstring_Ptr; External_Tag : Cstring_Ptr; HT_Link : Tag; Ancestor_Tags : Tag_Table (Natural); end record; type Vtable_Entry is record Pfn : System.Address; end record; type Vtable_Entry_Array is array (Positive range <>) of Vtable_Entry; type VTable is record -- Offset_To_Top : Integer; -- Typeinfo_Ptr : System.Address; -- TSD is currently also here??? Prims_Ptr : Vtable_Entry_Array (Positive); end record; -- Note: See comment in a-tags.adb explaining why the components -- Offset_To_Top and Typeinfo_Ptr have been commented out. -- ----------------------------------------------------------------------- -- The size of the Prims_Ptr array actually depends on the tagged type to -- which it applies. For each tagged type, the expander computes the -- actual array size, allocates the Dispatch_Table record accordingly, and -- generates code that displaces the base of the record after the -- Typeinfo_Ptr component. For this reason the first two components have -- been commented in the previous declaration. The access to these -- components is done by means of local functions. --------------------------- -- Unchecked Conversions -- --------------------------- type Int_Ptr is access Integer; function To_Int_Ptr is new Unchecked_Conversion (System.Address, Int_Ptr); function To_Cstring_Ptr is new Unchecked_Conversion (Address, Cstring_Ptr); function To_Address is new Unchecked_Conversion (Cstring_Ptr, Address); ----------------------- -- Local Subprograms -- ----------------------- function Length (Str : Cstring_Ptr) return Natural; -- Length of string represented by the given pointer (treating the string -- as a C-style string, which is Nul terminated). function Offset_To_Top (T : Vtable_Ptr) return Integer; -- Returns the current value of the offset_to_top component available in -- the prologue of the dispatch table. function Typeinfo_Ptr (T : Vtable_Ptr) return System.Address; -- Returns the current value of the typeinfo_ptr component available in -- the prologue of the dispatch table. pragma Unreferenced (Offset_To_Top); pragma Unreferenced (Typeinfo_Ptr); -- These functions will be used for full compatibility with the C++ ABI ----------------------- -- CPP_CW_Membership -- ----------------------- function CPP_CW_Membership (Obj_Tag : Vtable_Ptr; Typ_Tag : Vtable_Ptr) return Boolean is Pos : constant Integer := TSD (Obj_Tag).Idepth - TSD (Typ_Tag).Idepth; begin return Pos >= 0 and then TSD (Obj_Tag).Ancestor_Tags (Pos) = Typ_Tag; end CPP_CW_Membership; --------------------------- -- CPP_Get_Expanded_Name -- --------------------------- function CPP_Get_Expanded_Name (T : Vtable_Ptr) return Address is begin return To_Address (TSD (T).Expanded_Name); end CPP_Get_Expanded_Name; -------------------------- -- CPP_Get_External_Tag -- -------------------------- function CPP_Get_External_Tag (T : Vtable_Ptr) return Address is begin return To_Address (TSD (T).External_Tag); end CPP_Get_External_Tag; ------------------------------- -- CPP_Get_Inheritance_Depth -- ------------------------------- function CPP_Get_Inheritance_Depth (T : Vtable_Ptr) return Natural is begin return TSD (T).Idepth; end CPP_Get_Inheritance_Depth; ------------------------- -- CPP_Get_Prim_Op_Address -- ------------------------- function CPP_Get_Prim_Op_Address (T : Vtable_Ptr; Position : Positive) return Address is begin return T.Prims_Ptr (Position).Pfn; end CPP_Get_Prim_Op_Address; ----------------------- -- CPP_Get_RC_Offset -- ----------------------- function CPP_Get_RC_Offset (T : Vtable_Ptr) return SSE.Storage_Offset is pragma Warnings (Off, T); begin return 0; end CPP_Get_RC_Offset; ------------------------------- -- CPP_Get_Remotely_Callable -- ------------------------------- function CPP_Get_Remotely_Callable (T : Vtable_Ptr) return Boolean is pragma Warnings (Off, T); begin return True; end CPP_Get_Remotely_Callable; ----------------- -- CPP_Get_TSD -- ----------------- function CPP_Get_TSD (T : Vtable_Ptr) return Address is use type System.Storage_Elements.Storage_Offset; TSD_Ptr : constant Addr_Ptr := To_Addr_Ptr (To_Address (T) - CPP_DT_Typeinfo_Ptr_Size); begin return TSD_Ptr.all; end CPP_Get_TSD; -------------------- -- CPP_Inherit_DT -- -------------------- procedure CPP_Inherit_DT (Old_T : Vtable_Ptr; New_T : Vtable_Ptr; Entry_Count : Natural) is begin if Old_T /= null then New_T.Prims_Ptr (1 .. Entry_Count) := Old_T.Prims_Ptr (1 .. Entry_Count); end if; end CPP_Inherit_DT; --------------------- -- CPP_Inherit_TSD -- --------------------- procedure CPP_Inherit_TSD (Old_TSD : Address; New_Tag : Vtable_Ptr) is Old_TSD_Ptr : constant Type_Specific_Data_Ptr := To_Type_Specific_Data_Ptr (Old_TSD); New_TSD_Ptr : constant Type_Specific_Data_Ptr := TSD (New_Tag); begin if Old_TSD_Ptr /= null then New_TSD_Ptr.Idepth := Old_TSD_Ptr.Idepth + 1; New_TSD_Ptr.Ancestor_Tags (1 .. New_TSD_Ptr.Idepth) := Old_TSD_Ptr.Ancestor_Tags (0 .. Old_TSD_Ptr.Idepth); else New_TSD_Ptr.Idepth := 0; end if; New_TSD_Ptr.Ancestor_Tags (0) := New_Tag; end CPP_Inherit_TSD; --------------------------- -- CPP_Set_Expanded_Name -- --------------------------- procedure CPP_Set_Expanded_Name (T : Vtable_Ptr; Value : Address) is begin TSD (T).Expanded_Name := To_Cstring_Ptr (Value); end CPP_Set_Expanded_Name; -------------------------- -- CPP_Set_External_Tag -- -------------------------- procedure CPP_Set_External_Tag (T : Vtable_Ptr; Value : Address) is begin TSD (T).External_Tag := To_Cstring_Ptr (Value); end CPP_Set_External_Tag; ------------------------------- -- CPP_Set_Inheritance_Depth -- ------------------------------- procedure CPP_Set_Inheritance_Depth (T : Vtable_Ptr; Value : Natural) is begin TSD (T).Idepth := Value; end CPP_Set_Inheritance_Depth; ----------------------------- -- CPP_Set_Prim_Op_Address -- ----------------------------- procedure CPP_Set_Prim_Op_Address (T : Vtable_Ptr; Position : Positive; Value : Address) is begin T.Prims_Ptr (Position).Pfn := Value; end CPP_Set_Prim_Op_Address; ----------------------- -- CPP_Set_RC_Offset -- ----------------------- procedure CPP_Set_RC_Offset (T : Vtable_Ptr; Value : SSE.Storage_Offset) is pragma Warnings (Off, T); pragma Warnings (Off, Value); begin null; end CPP_Set_RC_Offset; ------------------------------- -- CPP_Set_Remotely_Callable -- ------------------------------- procedure CPP_Set_Remotely_Callable (T : Vtable_Ptr; Value : Boolean) is pragma Warnings (Off, T); pragma Warnings (Off, Value); begin null; end CPP_Set_Remotely_Callable; ----------------- -- CPP_Set_TSD -- ----------------- procedure CPP_Set_TSD (T : Vtable_Ptr; Value : Address) is use type System.Storage_Elements.Storage_Offset; TSD_Ptr : constant Addr_Ptr := To_Addr_Ptr (To_Address (T) - CPP_DT_Typeinfo_Ptr_Size); begin TSD_Ptr.all := Value; end CPP_Set_TSD; -------------------- -- Displaced_This -- -------------------- function Displaced_This (Current_This : System.Address; Vptr : Vtable_Ptr; Position : Positive) return System.Address is pragma Warnings (Off, Vptr); pragma Warnings (Off, Position); begin return Current_This; -- why is the following here commented out ??? -- + Storage_Offset (Vptr.Prims_Ptr (Position).Delta1); end Displaced_This; ------------------- -- Expanded_Name -- ------------------- function Expanded_Name (T : Vtable_Ptr) return String is Result : constant Cstring_Ptr := TSD (T).Expanded_Name; begin return Result (1 .. Length (Result)); end Expanded_Name; ------------------ -- External_Tag -- ------------------ function External_Tag (T : Vtable_Ptr) return String is Result : constant Cstring_Ptr := TSD (T).External_Tag; begin return Result (1 .. Length (Result)); end External_Tag; ------------ -- Length -- ------------ function Length (Str : Cstring_Ptr) return Natural is Len : Integer := 1; begin while Str (Len) /= ASCII.Nul loop Len := Len + 1; end loop; return Len - 1; end Length; ------------------ -- Offset_To_Top -- ------------------ function Offset_To_Top (T : Vtable_Ptr) return Integer is use type System.Storage_Elements.Storage_Offset; TSD_Ptr : constant Int_Ptr := To_Int_Ptr (To_Address (T) - CPP_DT_Prologue_Size); begin return TSD_Ptr.all; end Offset_To_Top; ------------------ -- Typeinfo_Ptr -- ------------------ function Typeinfo_Ptr (T : Vtable_Ptr) return System.Address is use type System.Storage_Elements.Storage_Offset; TSD_Ptr : constant Addr_Ptr := To_Addr_Ptr (To_Address (T) - CPP_DT_Typeinfo_Ptr_Size); begin return TSD_Ptr.all; end Typeinfo_Ptr; --------- -- TSD -- --------- function TSD (T : Vtable_Ptr) return Type_Specific_Data_Ptr is begin return To_Type_Specific_Data_Ptr (CPP_Get_TSD (T)); end TSD; end Interfaces.CPP;