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Diffstat (limited to 'gcc/ada/s-finmas.ads')
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1 files changed, 135 insertions, 0 deletions
diff --git a/gcc/ada/s-finmas.ads b/gcc/ada/s-finmas.ads new file mode 100644 index 00000000000..26783d33172 --- /dev/null +++ b/gcc/ada/s-finmas.ads @@ -0,0 +1,135 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S Y S T E M . F I N A L I Z A T I O N _ M A S T E R S -- +-- -- +-- S p e c -- +-- -- +-- Copyright (C) 2011, 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 3, 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. -- +-- -- +-- As a special exception under Section 7 of GPL version 3, you are granted -- +-- additional permissions described in the GCC Runtime Library Exception, -- +-- version 3.1, as published by the Free Software Foundation. -- +-- -- +-- You should have received a copy of the GNU General Public License and -- +-- a copy of the GCC Runtime Library Exception along with this program; -- +-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- +-- <http://www.gnu.org/licenses/>. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +with Ada.Finalization; +with Ada.Unchecked_Conversion; + +with System.Storage_Elements; +with System.Storage_Pools; + +package System.Finalization_Masters is + pragma Preelaborate (System.Finalization_Masters); + + -- A reference to primitive Finalize_Address. The expander generates an + -- implementation of this procedure for each controlled and class-wide + -- type. Since controlled objects are simply viewed as addresses once + -- allocated through a master, Finalize_Address provides a backward + -- indirection from an address to a type-specific context. + + type Finalize_Address_Ptr is access procedure (Obj : System.Address); + + -- Heterogeneous collection type structure. The implementation allows for + -- finalizable objects of different base types to be serviced by the same + -- master. + + type FM_Node; + type FM_Node_Ptr is access all FM_Node; + + type FM_Node is record + Prev : FM_Node_Ptr := null; + Next : FM_Node_Ptr := null; + Finalize_Address : Finalize_Address_Ptr := null; + end record; + + -- A reference to any derivation from Root_Storage_Pool. Since this type + -- may not be used to allocate objects, its storage size is zero. + + type Any_Storage_Pool_Ptr is + access System.Storage_Pools.Root_Storage_Pool'Class; + for Any_Storage_Pool_Ptr'Storage_Size use 0; + + -- Finalization master type structure. A unique master is associated with + -- each access-to-controlled or access-to-class-wide type. Masters also act + -- as components of subpools. + + type Finalization_Master is + new Ada.Finalization.Limited_Controlled with + record + Base_Pool : Any_Storage_Pool_Ptr := null; + -- A reference to the pool which this finalization master services. This + -- field is used in conjunction with the build-in-place machinery. + + Objects : aliased FM_Node; + -- A doubly linked list which contains the headers of all controlled + -- objects allocated in a [sub]pool. + + Finalization_Started : Boolean := False; + pragma Atomic (Finalization_Started); + -- A flag used to detect allocations which occur during the finalization + -- of a master. The allocations must raise Program_Error. This scenario + -- may arise in a multitask environment. The flag is atomic because it + -- is accessed without Lock_Task / Unlock_Task. + end record; + + type Finalization_Master_Ptr is access all Finalization_Master; + for Finalization_Master_Ptr'Storage_Size use 0; + + -- Since RTSfind cannot contain names of the form RE_"+", the following + -- routine serves as a wrapper around System.Storage_Elements."+". + + function Add_Offset_To_Address + (Addr : System.Address; + Offset : System.Storage_Elements.Storage_Offset) return System.Address; + + function Address_To_FM_Node_Ptr is + new Ada.Unchecked_Conversion (Address, FM_Node_Ptr); + + procedure Attach (N : not null FM_Node_Ptr; L : not null FM_Node_Ptr); + -- Prepend a node to a specific finalization master + + function Base_Pool + (Master : Finalization_Master) return Any_Storage_Pool_Ptr; + -- Return a reference to the underlying storage pool on which the master + -- operates. + + procedure Detach (N : not null FM_Node_Ptr); + -- Remove a node from an arbitrary finalization master + + overriding procedure Finalize (Master : in out Finalization_Master); + -- Lock the master to prevent allocations during finalization. Iterate over + -- the list of allocated controlled objects, finalizing each one by calling + -- its specific Finalize_Address. In the end, deallocate the dummy head. + + function Header_Size return System.Storage_Elements.Storage_Count; + -- Return the size of type FM_Node as Storage_Count + + function Header_Offset return System.Storage_Elements.Storage_Offset; + -- Return the size of type FM_Node as Storage_Offset + + overriding procedure Initialize (Master : in out Finalization_Master); + -- Initialize the dummy head of a finalization master + + procedure Set_Base_Pool + (Master : in out Finalization_Master; + Pool_Ptr : Any_Storage_Pool_Ptr); + -- Set the underlying pool of a finalization master + +end System.Finalization_Masters; |