140 lines
5.7 KiB
Ada
140 lines
5.7 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT RUN-TIME COMPONENTS --
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-- --
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-- G N A T . C P P _ E X C E P T I O N S --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 2013, AdaCore --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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with System;
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with System.Storage_Elements;
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with Interfaces.C; use Interfaces.C;
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with Ada.Unchecked_Conversion;
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with System.Standard_Library; use System.Standard_Library;
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package body GNAT.CPP_Exceptions is
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-- Note: all functions prefixed by __cxa are part of the c++ ABI for
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-- exception handling. As they are provided by the c++ library, there
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-- must be no dependencies on it in the compiled code of this unit, but
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-- there can be dependencies in instances. This is required to be able
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-- to build the shared library without the c++ library.
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function To_Exception_Data_Ptr is new
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Ada.Unchecked_Conversion
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(Exception_Id, Exception_Data_Ptr);
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-- Convert an Exception_Id to its non-private type. This is used to get
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-- the RTTI of a C++ exception
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function Get_Exception_Machine_Occurrence
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(X : Exception_Occurrence) return System.Address;
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pragma Import (Ada, Get_Exception_Machine_Occurrence,
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"__gnat_get_exception_machine_occurrence");
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-- Imported function (from Ada.Exceptions) that returns the machine
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-- occurrence from an exception occurrence.
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-------------------------
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-- Raise_Cpp_Exception --
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-------------------------
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procedure Raise_Cpp_Exception (Id : Exception_Id; Value : T)
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is
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Id_Data : constant Exception_Data_Ptr := To_Exception_Data_Ptr (Id);
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-- Get a non-private view on the exception
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type T_Acc is access all T;
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pragma Convention (C, T_Acc);
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-- Access type to the object compatible with C
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Occ : T_Acc;
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-- The occurrence to propagate
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function cxa_allocate_exception (Size : size_t) return T_Acc;
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pragma Import (C, cxa_allocate_exception, "__cxa_allocate_exception");
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-- The C++ function to allocate an occurrence
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procedure cxa_throw (Obj : T_Acc; Tinfo : System.Address;
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Dest : System.Address);
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pragma Import (C, cxa_throw, "__cxa_throw");
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pragma No_Return (cxa_throw);
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-- The C++ function to raise an exception
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begin
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-- Check the exception was imported from C++
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if Id_Data.Lang /= 'C' then
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raise Constraint_Error;
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end if;
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-- Allocate the C++ occurrence
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Occ := cxa_allocate_exception (T'Size / System.Storage_Unit);
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-- Set the object
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Occ.all := Value;
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-- Throw the exception
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cxa_throw (Occ, Id_Data.Foreign_Data, System.Null_Address);
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end Raise_Cpp_Exception;
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----------------
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-- Get_Object --
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----------------
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function Get_Object (X : Exception_Occurrence) return T
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is
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use System;
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use System.Storage_Elements;
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Unwind_Exception_Size : Natural;
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pragma Import (C, Unwind_Exception_Size, "__gnat_unwind_exception_size");
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-- Size in bytes of _Unwind_Exception
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Exception_Addr : constant Address :=
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Get_Exception_Machine_Occurrence (X);
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-- Machine occurrence of X
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begin
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-- Check the machine occurrence exists
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if Exception_Addr = Null_Address then
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raise Constraint_Error;
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end if;
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declare
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-- Import the object from the occurrence
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Result : T;
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pragma Import (Ada, Result);
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for Result'Address use
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Exception_Addr + Storage_Offset (Unwind_Exception_Size);
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begin
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-- And return it
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return Result;
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end;
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end Get_Object;
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end GNAT.CPP_Exceptions;
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