File : s-finimp.adb
------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- S Y S T E M . F I N A L I Z A T I O N _ I M P L E M E N T A T I O N --
-- --
-- B o d y --
-- --
-- $Revision: 1.39 $
-- --
-- Copyright (C) 1992-1999 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. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
with Ada.Exceptions;
with Ada.Tags;
with Ada.Unchecked_Conversion;
with System.Storage_Elements;
with System.Soft_Links;
package body System.Finalization_Implementation is
use Ada.Exceptions;
use System.Finalization_Root;
package TSL renames System.Soft_Links;
package SSE renames System.Storage_Elements;
use type SSE.Storage_Offset;
function To_Finalizable_Ptr is
new Ada.Unchecked_Conversion (Address, Finalizable_Ptr);
function To_Addr is
new Ada.Unchecked_Conversion (Finalizable_Ptr, Address);
type RC_Ptr is access all Record_Controller;
function To_RC_Ptr is
new Ada.Unchecked_Conversion (Address, RC_Ptr);
procedure Raise_Exception_No_Defer
(E : in Exception_Id;
Message : in String := "");
pragma Import (Ada, Raise_Exception_No_Defer,
"ada__exceptions__raise_exception_no_defer");
pragma No_Return (Raise_Exception_No_Defer);
-- Raise an exception without deferring abort. Note that we have to
-- use this rather kludgy Ada Import interface, since this subprogram
-- is not available in the visible spec of Ada.Exceptions.
procedure Raise_From_Finalize
(L : Finalizable_Ptr;
From_Abort : Boolean;
E_Occ : Exception_Occurrence);
-- Deal with an exception raised during finalization of a list. L is a
-- pointer to the list of element not yet finalized. From_Abort is true
-- if the finalization actions come from an abort rather than a normal
-- exit. E_Occ represents the exception being raised.
--------------------------
-- Attach_To_Final_List --
--------------------------
procedure Attach_To_Final_List
(L : in out Finalizable_Ptr;
Obj : in out Finalizable;
Nb_Link : Short_Short_Integer)
is
begin
-- Simple case: attachement to a one way list
if Nb_Link = 1 then
Obj.Next := L;
L := Obj'Unchecked_Access;
-- Dynamically allocated objects: they are attached to a doubly
-- linked list, so that an element can be finalized at any moment
-- by means of an unchecked deallocation. Attachement is
-- protected against multi-threaded access.
elsif Nb_Link = 2 then
TSL.Lock_Task.all;
Obj.Next := L.Next;
Obj.Prev := L.Next.Prev;
L.Next.Prev := Obj'Unchecked_Access;
L.Next := Obj'Unchecked_Access;
TSL.Unlock_Task.all;
-- Attachement of arrays to the final list (used only for objects
-- returned by function). Obj, in this case is the last element,
-- but all other elements are already threaded after it. We just
-- attach the rest of the final list at the end of the array list.
elsif Nb_Link = 3 then
declare
P : Finalizable_Ptr := Obj'Unchecked_Access;
begin
while P.Next /= null loop
P := P.Next;
end loop;
P.Next := L;
L := Obj'Unchecked_Access;
end;
end if;
end Attach_To_Final_List;
-----------------------------
-- Detach_From_Final_List --
-----------------------------
-- We know that the detach object is neither at the beginning nor at the
-- end of the list, thank's to the dummy First and Last Elements
procedure Detach_From_Final_List (Obj : in out Finalizable) is
begin
TSL.Lock_Task.all;
Obj.Next.Prev := Obj.Prev;
Obj.Prev.Next := Obj.Next;
TSL.Unlock_Task.all;
end Detach_From_Final_List;
--------------------------
-- Raise_From_Finalize --
--------------------------
procedure Raise_From_Finalize
(L : Finalizable_Ptr;
From_Abort : Boolean;
E_Occ : Exception_Occurrence)
is
Msg : constant String := Exception_Message (E_Occ);
P : Finalizable_Ptr := L;
Q : Finalizable_Ptr;
begin
-- We already got an exception. We now finalize the remainder of
-- the list, ignoring all further exceptions.
while P /= null loop
Q := P.Next;
begin
Finalize (P.all);
exception
when others => null;
end;
P := Q;
end loop;
-- If finalization from an Abort, then nothing to do
if From_Abort then
null;
-- If no message, then add our own message saying what happened
elsif Msg = "" then
Raise_Exception_No_Defer
(E => Program_Error'Identity,
Message => "exception " &
Exception_Name (E_Occ) &
" raised during finalization");
-- If there was a message, pass it on
else
Raise_Exception_No_Defer (Program_Error'Identity, Msg);
end if;
end Raise_From_Finalize;
-------------------
-- Finalize_List --
-------------------
procedure Finalize_List (L : Finalizable_Ptr) is
P : Finalizable_Ptr := L;
Q : Finalizable_Ptr;
type Fake_Exception_Occurence is record
Id : Exception_Id;
end record;
type Ptr is access all Fake_Exception_Occurence;
-- Let's get the current exception before starting to finalize in
-- order to check if we are in the abort case if an exception is
-- raised.
function To_Ptr is new
Ada.Unchecked_Conversion (Exception_Occurrence_Access, Ptr);
X : Exception_Id :=
To_Ptr (System.Soft_Links.Get_Current_Excep.all).Id;
begin
while P /= null loop
Q := P.Next;
Finalize (P.all);
P := Q;
end loop;
exception
when E_Occ : others =>
Raise_From_Finalize (
Q,
X = Standard'Abort_Signal'Identity,
E_Occ);
end Finalize_List;
--------------------------
-- Finalize_Global_List --
--------------------------
procedure Finalize_Global_List is
begin
-- There are three case here:
-- a. the application uses tasks, in which case Finalize_Global_Tasks
-- will defer abortion
-- b. the application doesn't use tasks but uses other tasking
-- constructs, such as ATCs and protected objects. In this case,
-- the binder will call Finalize_Global_List instead of
-- Finalize_Global_Tasks, letting abort undeferred, and leading
-- to assertion failures in the GNULL
-- c. the application doesn't use any tasking construct in which case
-- deferring abort isn't necessary.
--
-- Until another solution is found to deal with case b, we need to
-- call abort_defer here to pass the checks, but we do not need to
-- undefer abortion, since Finalize_Global_List is the last procedure
-- called before exiting the partition.
TSL.Abort_Defer.all;
Finalize_List (Global_Final_List);
end Finalize_Global_List;
------------------
-- Finalize_One --
------------------
procedure Finalize_One (Obj : in out Finalizable) is
begin
Detach_From_Final_List (Obj);
Finalize (Obj);
exception
when E_Occ : others => Raise_From_Finalize (null, False, E_Occ);
end Finalize_One;
function RC_Offset (T : Ada.Tags.Tag) return SSE.Storage_Offset;
pragma Import (Ada, RC_Offset, "ada__tags__get_rc_offset");
function Parent_Size (Obj : Address) return SSE.Storage_Count;
pragma Import (Ada, Parent_Size, "ada__tags__parent_size");
function Get_RC_Dynamically (Obj : Address) return Address;
-- Given an the address of an object (obj) of a tagged extension with
-- controlled component, computes the address of the record controller
-- located just after the _parent field
------------------------
-- Get_RC_Dynamically --
------------------------
function Get_RC_Dynamically (Obj : Address) return Address is
-- define a faked record controller to avoid generating
-- unnecessary expanded code for controlled types
type Faked_Record_Controller is record
Tag, Prec, Next : Address;
end record;
-- Reconstruction of a type with characteristics
-- comparable to the original type
D : constant := Storage_Unit - 1;
type Faked_Type_Of_Obj is record
Parent : SSE.Storage_Array
(1 .. (Parent_Size (Obj) + D) / Storage_Unit);
Controller : Faked_Record_Controller;
end record;
type Obj_Ptr is access all Faked_Type_Of_Obj;
function To_Obj_Ptr is new Ada.Unchecked_Conversion (Address, Obj_Ptr);
begin
return To_Obj_Ptr (Obj).Controller'Address;
end Get_RC_Dynamically;
--------------------------
-- Deep_Tag_Initialize --
--------------------------
procedure Deep_Tag_Initialize
(L : in out SFR.Finalizable_Ptr;
A : System.Address;
B : Short_Short_Integer)
is
V : constant SFR.Finalizable_Ptr := To_Finalizable_Ptr (A);
Offset : constant SSE.Storage_Offset := RC_Offset (V'Tag);
Controller : RC_Ptr;
begin
-- This procedure should not be called if the object has no
-- controlled components
if Offset = 0 then
raise Program_Error;
-- Has controlled components
else
if Offset > 0 then
Controller := To_RC_Ptr (A + Offset);
else
Controller := To_RC_Ptr (Get_RC_Dynamically (A));
end if;
end if;
Initialize (Controller.all);
Attach_To_Final_List (L, Controller.all, B);
-- Is controlled
if V.all in Finalizable then
Initialize (V.all);
Attach_To_Final_List (Controller.F, Finalizable (Controller.all), 1);
end if;
end Deep_Tag_Initialize;
----------------------
-- Deep_Tag_Adjust --
----------------------
procedure Deep_Tag_Adjust
(L : in out SFR.Finalizable_Ptr;
A : System.Address;
B : Short_Short_Integer)
is
V : constant SFR.Finalizable_Ptr := To_Finalizable_Ptr (A);
Offset : constant SSE.Storage_Offset := RC_Offset (V'Tag);
Controller : RC_Ptr;
begin
-- Has controlled components
if Offset /= 0 then
if Offset > 0 then
Controller := To_RC_Ptr (A + Offset);
else
Controller := To_RC_Ptr (Get_RC_Dynamically (A));
end if;
Adjust (Controller.all);
Attach_To_Final_List (L, Controller.all, B);
-- Is controlled
elsif V.all in Finalizable then
Adjust (V.all);
Attach_To_Final_List (L, Finalizable (V.all), 1);
end if;
end Deep_Tag_Adjust;
------------------------
-- Deep_Tag_Finalize --
------------------------
procedure Deep_Tag_Finalize
(L : in out SFR.Finalizable_Ptr;
A : System.Address;
B : Boolean)
is
V : constant SFR.Finalizable_Ptr := To_Finalizable_Ptr (A);
Offset : constant SSE.Storage_Offset := RC_Offset (V'Tag);
Controller : RC_Ptr;
begin
-- Has controlled components
if Offset /= 0 then
if Offset > 0 then
Controller := To_RC_Ptr (A + Offset);
else
Controller := To_RC_Ptr (Get_RC_Dynamically (A));
end if;
if B then
Finalize_One (Controller.all);
else
Finalize (Controller.all);
end if;
-- Is controlled
elsif V.all in Finalizable then
if B then
Finalize_One (V.all);
else
Finalize (V.all);
end if;
end if;
end Deep_Tag_Finalize;
----------------------
-- Deep_Tag_Attach --
-----------------------
procedure Deep_Tag_Attach
(L : in out SFR.Finalizable_Ptr;
A : System.Address;
B : Short_Short_Integer)
is
V : constant SFR.Finalizable_Ptr := To_Finalizable_Ptr (A);
Offset : constant SSE.Storage_Offset := RC_Offset (V'Tag);
Controller : RC_Ptr;
begin
if Offset /= 0 then
if Offset > 0 then
Controller := To_RC_Ptr (A + Offset);
else
Controller := To_RC_Ptr (Get_RC_Dynamically (A));
end if;
Attach_To_Final_List (L, Controller.all, B);
-- Is controlled
elsif V.all in Finalizable then
Attach_To_Final_List (L, V.all, B);
end if;
end Deep_Tag_Attach;
----------------------------------
-- Record_Controller Management --
----------------------------------
----------------
-- Initialize --
----------------
procedure Initialize (Object : in out Limited_Record_Controller) is
begin
null;
end Initialize;
procedure Initialize (Object : in out Record_Controller) is
begin
Object.My_Address := Object'Address;
end Initialize;
-------------
-- Adjust --
-------------
procedure Adjust (Object : in out Record_Controller) is
My_Offset : constant SSE.Storage_Offset :=
Object.My_Address - Object'Address;
procedure Ptr_Adjust (Ptr : in out Finalizable_Ptr);
-- Substract the offset to the pointer
procedure Reverse_Adjust (P : Finalizable_Ptr);
-- Ajust the components in the reverse order in which they are stored
-- on the finalization list. (Adjust and Finalization are not done in
-- the same order)
procedure Ptr_Adjust (Ptr : in out Finalizable_Ptr) is
begin
if Ptr /= null then
Ptr := To_Finalizable_Ptr (To_Addr (Ptr) - My_Offset);
end if;
end Ptr_Adjust;
procedure Reverse_Adjust (P : Finalizable_Ptr) is
begin
if P /= null then
Ptr_Adjust (P.Next);
Reverse_Adjust (P.Next);
Adjust (P.all);
end if;
end Reverse_Adjust;
begin
-- Adjust the components and their finalization pointers next
Ptr_Adjust (Object.F);
Reverse_Adjust (Object.F);
-- then Adjust the object itself
Object.My_Address := Object'Address;
end Adjust;
--------------
-- Finalize --
--------------
procedure Finalize (Object : in out Limited_Record_Controller) is
begin
Finalize_List (Object.F);
end Finalize;
end System.Finalization_Implementation;