105 lines
5.8 KiB
Ada
105 lines
5.8 KiB
Ada
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------------------------------------------------------------------------------
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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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-- S p e c --
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-- --
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-- Copyright (C) 1999-2014, Free Software Foundation, Inc. --
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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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pragma Compiler_Unit_Warning;
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pragma Polling (Off);
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-- We must turn polling off for this unit, because otherwise we get
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-- elaboration circularities with System.Exception_Tables.
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with System.Storage_Elements;
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package System.Machine_State_Operations is
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subtype Code_Loc is System.Address;
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-- Code location used in building exception tables and for call addresses
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-- when propagating an exception (also traceback table) Values of this
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-- type are created by using Label'Address or extracted from machine
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-- states using Get_Code_Loc.
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type Machine_State is new System.Address;
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-- The table based exception handling approach (see a-except.adb) isolates
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-- the target dependent aspects using an abstract data type interface
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-- to the type Machine_State, which is represented as a System.Address
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-- value (presumably implemented as a pointer to an appropriate record
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-- structure).
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function Machine_State_Length return System.Storage_Elements.Storage_Offset;
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-- Function to determine the length of the Storage_Array needed to hold
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-- a machine state. The machine state will always be maximally aligned.
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-- The value returned is a constant that will be used to allocate space
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-- for a machine state value.
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function Allocate_Machine_State return Machine_State;
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-- Allocate the required space for a Machine_State
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procedure Free_Machine_State (M : in out Machine_State);
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-- Free the dynamic memory taken by Machine_State
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-- The initial value of type Machine_State is created by the low level
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-- routine that actually raises an exception using the special builtin
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-- _builtin_machine_state. This value will typically encode the value of
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-- the program counter, and relevant registers. The following operations
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-- are defined on Machine_State values:
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function Get_Code_Loc (M : Machine_State) return Code_Loc;
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-- This function extracts the program counter value from a machine state,
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-- which the caller uses for searching the exception tables, and also for
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-- recording entries in the traceback table. The call returns a value of
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-- Null_Loc if the machine state represents the outer level, or some other
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-- frame for which no information can be provided.
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procedure Pop_Frame (M : Machine_State);
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-- This procedure pops the machine state M so that it represents the
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-- call point, as though the current subprogram had returned. It changes
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-- only the value referenced by M, and does not affect the current stack
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-- environment.
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function Fetch_Code (Loc : Code_Loc) return Code_Loc;
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-- Some architectures (notably HPUX) use a descriptor to describe a
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-- subprogram address. This function computes the actual starting
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-- address of the code from Loc.
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--
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-- Do not add pragma Inline to this function: there is a curious
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-- interaction between rtsfind and front-end inlining. The exception
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-- declaration in s-auxdec calls rtsfind, which forces several other system
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-- packages to be compiled. Some of those have a pragma Inline, and we
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-- compile the corresponding bodies so that inlining can take place. One
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-- of these packages is s-mastop, which depends on s-auxdec, which is still
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-- being compiled: we have not seen all the declarations in it yet, so we
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-- get confused semantic errors ???
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procedure Set_Machine_State (M : Machine_State);
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-- This routine sets M from the current machine state. It is called when an
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-- exception is initially signalled to initialize the state.
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end System.Machine_State_Operations;
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