166 lines
6.6 KiB
Ada
166 lines
6.6 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- SYSTEM.MACHINE_STATE_OPERATIONS --
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-- --
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-- B o d y --
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-- (Version for Alpha/Dec Unix) --
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-- --
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-- Copyright (C) 1999-2005, 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 2, 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. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING. If not, write --
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-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
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-- Boston, MA 02110-1301, USA. --
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-- --
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-- As a special exception, if other files instantiate generics from this --
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-- unit, or you link this unit with other files to produce an executable, --
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-- this unit does not by itself cause the resulting executable to be --
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-- covered by the GNU General Public License. This exception does not --
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-- however invalidate any other reasons why the executable file might be --
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-- covered by the GNU Public License. --
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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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-- This version of System.Machine_State_Operations is for use on
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-- Alpha systems running DEC Unix.
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with System.Memory;
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package body System.Machine_State_Operations is
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pragma Linker_Options ("-lexc");
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-- Needed for definitions of exc_capture_context and exc_virtual_unwind
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----------------------------
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-- Allocate_Machine_State --
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----------------------------
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function Allocate_Machine_State return Machine_State is
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use System.Storage_Elements;
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function c_machine_state_length return Storage_Offset;
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pragma Import (C, c_machine_state_length, "__gnat_machine_state_length");
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begin
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return Machine_State
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(Memory.Alloc (Memory.size_t (c_machine_state_length)));
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end Allocate_Machine_State;
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----------------
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-- Fetch_Code --
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----------------
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function Fetch_Code (Loc : Code_Loc) return Code_Loc is
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begin
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return Loc;
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end Fetch_Code;
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------------------------
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-- Free_Machine_State --
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------------------------
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procedure Free_Machine_State (M : in out Machine_State) is
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begin
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Memory.Free (Address (M));
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M := Machine_State (Null_Address);
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end Free_Machine_State;
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------------------
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-- Get_Code_Loc --
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------------------
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function Get_Code_Loc (M : Machine_State) return Code_Loc is
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Asm_Call_Size : constant := 4;
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function c_get_code_loc (M : Machine_State) return Code_Loc;
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pragma Import (C, c_get_code_loc, "__gnat_get_code_loc");
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-- Code_Loc returned by c_get_code_loc is the return point but here we
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-- want Get_Code_Loc to return the call point. Under DEC Unix a call
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-- asm instruction takes 4 bytes. So we must remove this value from
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-- c_get_code_loc to have the call point.
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Loc : constant Code_Loc := c_get_code_loc (M);
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begin
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if Loc = 0 then
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return 0;
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else
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return Loc - Asm_Call_Size;
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end if;
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end Get_Code_Loc;
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--------------------------
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-- Machine_State_Length --
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--------------------------
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function Machine_State_Length
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return System.Storage_Elements.Storage_Offset
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is
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use System.Storage_Elements;
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function c_machine_state_length return Storage_Offset;
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pragma Import (C, c_machine_state_length, "__gnat_machine_state_length");
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begin
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return c_machine_state_length;
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end Machine_State_Length;
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---------------
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-- Pop_Frame --
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---------------
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procedure Pop_Frame (M : Machine_State) is
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procedure exc_virtual_unwind (Fcn : System.Address; M : Machine_State);
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pragma Import (C, exc_virtual_unwind, "exc_virtual_unwind");
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function exc_lookup_function (Loc : Code_Loc) return System.Address;
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pragma Import (C, exc_lookup_function, "exc_lookup_function_entry");
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procedure c_set_code_loc (M : Machine_State; Loc : Code_Loc);
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pragma Import (C, c_set_code_loc, "__gnat_set_code_loc");
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-- Look for a code-range descriptor table containing the PC of the
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-- specified machine state. If we don't find any, attempting to unwind
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-- further would fail so we set the machine state's code location to a
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-- value indicating that the top of the call chain is reached. This
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-- happens when the function at the address pointed to by PC has not
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-- been registered with the unwinding machinery, as with the __istart
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-- functions generated by the linker in presence of initialization
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-- routines for example.
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Prf : constant System.Address := exc_lookup_function (Get_Code_Loc (M));
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begin
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if Prf = System.Null_Address then
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c_set_code_loc (M, 0);
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else
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exc_virtual_unwind (Prf, M);
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end if;
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end Pop_Frame;
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-----------------------
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-- Set_Machine_State --
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-----------------------
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procedure Set_Machine_State (M : Machine_State) is
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procedure c_capture_context (M : Machine_State);
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pragma Import (C, c_capture_context, "exc_capture_context");
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begin
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c_capture_context (M);
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Pop_Frame (M);
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end Set_Machine_State;
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end System.Machine_State_Operations;
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