83 lines
4.4 KiB
Ada
83 lines
4.4 KiB
Ada
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------------------------------------------------------------------------------
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-- --
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-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
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-- --
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-- S Y S T E M . S T A C K _ C H E C K I N G --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1999-2013, Free Software Foundation, Inc. --
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-- --
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-- GNARL 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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-- GNARL was developed by the GNARL team at Florida State 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 package provides a system-independent implementation of stack
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-- checking using comparison with stack base and limit.
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-- This package defines basic types and objects. Operations related to
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-- stack checking can be found in package System.Stack_Checking.Operations.
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pragma Compiler_Unit_Warning;
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with System.Storage_Elements;
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package System.Stack_Checking is
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pragma Preelaborate;
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pragma Elaborate_Body;
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-- This unit has a junk null body. The reason is that historically we
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-- used to have a real body, and it causes bootstrapping path problems
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-- to eliminate it, since the old body may still be present in the
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-- compilation environment for a build.
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type Stack_Info is record
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Limit : System.Address := System.Null_Address;
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Base : System.Address := System.Null_Address;
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Size : System.Storage_Elements.Storage_Offset := 0;
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end record;
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-- This record may be part of a larger data structure like the
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-- task control block in the tasking case.
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-- This specific layout has the advantage of being compatible with the
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-- Intel x86 BOUNDS instruction.
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type Stack_Access is access all Stack_Info;
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-- Unique local storage associated with a specific task. This storage is
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-- used for the stack base and limit, and is returned by Checked_Self.
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-- Only self may write this information, it may be read by any task.
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-- At no time the address range Limit .. Base (or Base .. Limit for
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-- upgrowing stack) may contain any address that is part of another stack.
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-- The Stack_Access may be part of a larger data structure.
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Multi_Processor : constant Boolean := False; -- Not supported yet
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private
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Null_Stack_Info : aliased Stack_Info :=
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(Limit => System.Null_Address,
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Base => System.Null_Address,
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Size => 0);
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-- Use explicit assignment to avoid elaboration code (call to init proc)
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Null_Stack : constant Stack_Access := Null_Stack_Info'Access;
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-- Stack_Access value that will return a Stack_Base and Stack_Limit
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-- that fail any stack check.
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end System.Stack_Checking;
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