------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME COMPONENTS -- -- -- -- A D A . T A G S -- -- -- -- S p e c -- -- -- -- -- -- Copyright (C) 1992-2001 Free Software Foundation, Inc. -- -- -- -- This specification is derived from the Ada Reference Manual for use with -- -- GNAT. The copyright notice above, and the license provisions that follow -- -- apply solely to the contents of the part following the private keyword. -- -- -- -- 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 System; with System.Storage_Elements; package Ada.Tags is pragma Elaborate_Body; type Tag is private; function Expanded_Name (T : Tag) return String; function External_Tag (T : Tag) return String; function Internal_Tag (External : String) return Tag; Tag_Error : exception; private ---------------------------------------------------------------- -- Abstract procedural interface for the GNAT dispatch table -- ---------------------------------------------------------------- -- GNAT's Dispatch Table format is customizable in order to match the -- format used in another language. GNAT supports programs that use -- two different dispatch table format at the same time: the native -- format that supports Ada 95 tagged types and which is described in -- Ada.Tags and a foreign format for types that are imported from some -- other language (typically C++) which is described in interfaces.cpp. -- The runtime information kept for each tagged type is separated into -- two objects: the Dispatch Table and the Type Specific Data record. -- These two objects are allocated statically using the constants: -- DT Size = DT_Prologue_Size + Nb_Prim * DT_Entry_Size -- TSD Size = TSD_Prologue_Size + (1 + Idepth) * TSD_Entry_Size -- where Nb_prim is the number of primitive operations of the given -- type and Idepth its inheritance depth. -- The compiler generates calls to the following SET routines to -- initialize those structures and uses the GET functions to -- retreive the information when needed package S renames System; package SSE renames System.Storage_Elements; function CW_Membership (Obj_Tag : Tag; Typ_Tag : Tag) return Boolean; -- Given the tag of an object and the tag associated to a type, return -- true if Obj is in Typ'Class. function Get_Expanded_Name (T : Tag) return S.Address; -- Retrieve the address of a null terminated string containing -- the expanded name function Get_External_Tag (T : Tag) return S.Address; -- Retrieve the address of a null terminated string containing -- the external name function Get_Prim_Op_Address (T : Tag; 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) function Get_Inheritance_Depth (T : Tag) return Natural; -- Given a pointer to a dispatch Table, retrieves the value representing -- the depth in the inheritance tree (used for membership). function Get_RC_Offset (T : Tag) return SSE.Storage_Offset; -- Return the Offset of the implicit record controller when the object -- has controlled components. O otherwise. pragma Export (Ada, Get_RC_Offset, "ada__tags__get_rc_offset"); -- This procedure is used in s-finimp to compute the deep routines -- it is exported manually in order to avoid changing completely the -- organization of the run time. function Get_Remotely_Callable (T : Tag) return Boolean; -- Return the value previously set by Set_Remotely_Callable function Get_TSD (T : Tag) 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 procedure Inherit_DT (Old_T : Tag; New_T : Tag; 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 Inherit_TSD (Old_TSD : S.Address; New_Tag : Tag); -- Entry point used to initialize the TSD of a type knowing the -- TSD of the direct ancestor. function Parent_Size (Obj : S.Address) return SSE.Storage_Count; -- Computes the size of field _Parent of a tagged extension object -- whose address is 'obj' by calling the indirectly _size function of -- the parent. This function assumes that _size is always in slot 1 of -- the dispatch table. pragma Export (Ada, Parent_Size, "ada__tags__parent_size"); -- This procedure is used in s-finimp and is thus exported manually procedure Register_Tag (T : Tag); -- Insert the Tag and its associated external_tag in a table for the -- sake of Internal_Tag procedure Set_Inheritance_Depth (T : Tag; Value : Natural); -- Given a pointer to a dispatch Table, stores the value representing -- the depth in the inheritance tree (the second parameter). Used during -- elaboration of the tagged type. procedure Set_Prim_Op_Address (T : Tag; 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) procedure Set_TSD (T : Tag; 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 procedure Set_Expanded_Name (T : Tag; Value : S.Address); -- Set the address of the string containing the expanded name -- in the Dispatch table procedure Set_External_Tag (T : Tag; Value : S.Address); -- Set the address of the string containing the external tag -- in the Dispatch table procedure Set_RC_Offset (T : Tag; Value : SSE.Storage_Offset); -- Sets the Offset of the implicit record controller when the object -- has controlled components. Set to O otherwise. procedure Set_Remotely_Callable (T : Tag; Value : Boolean); -- Set to true if the type has been declared in a context described -- in E.4 (18) DT_Prologue_Size : constant SSE.Storage_Count := SSE.Storage_Count (Standard'Address_Size / S.Storage_Unit); -- Size of the first part of the dispatch table DT_Entry_Size : constant SSE.Storage_Count := SSE.Storage_Count (Standard'Address_Size / S.Storage_Unit); -- Size of each primitive operation entry in the Dispatch Table. TSD_Prologue_Size : constant SSE.Storage_Count := SSE.Storage_Count (6 * Standard'Address_Size / S.Storage_Unit); -- Size of the first part of the type specific data TSD_Entry_Size : constant SSE.Storage_Count := SSE.Storage_Count (Standard'Address_Size / S.Storage_Unit); -- Size of each ancestor tag entry in the TSD type Address_Array is array (Natural range <>) of S.Address; type Dispatch_Table; type Tag is access all Dispatch_Table; type Type_Specific_Data; type Type_Specific_Data_Ptr is access all Type_Specific_Data; pragma Inline_Always (CW_Membership); pragma Inline_Always (Get_Expanded_Name); pragma Inline_Always (Get_Inheritance_Depth); pragma Inline_Always (Get_Prim_Op_Address); pragma Inline_Always (Get_RC_Offset); pragma Inline_Always (Get_Remotely_Callable); pragma Inline_Always (Get_TSD); pragma Inline_Always (Inherit_DT); pragma Inline_Always (Inherit_TSD); pragma Inline_Always (Register_Tag); pragma Inline_Always (Set_Expanded_Name); pragma Inline_Always (Set_External_Tag); pragma Inline_Always (Set_Inheritance_Depth); pragma Inline_Always (Set_Prim_Op_Address); pragma Inline_Always (Set_RC_Offset); pragma Inline_Always (Set_Remotely_Callable); pragma Inline_Always (Set_TSD); end Ada.Tags;