83 lines
4.5 KiB
Ada
83 lines
4.5 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 . O P E R A T I O N S --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1999-2009, 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 implementation of stack checking operations using
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-- comparison with stack base and limit.
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pragma Restrictions (No_Elaboration_Code);
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-- We want to guarantee the absence of elaboration code because the binder
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-- does not handle references to this package.
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pragma Polling (Off);
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-- Turn off polling, we do not want polling to take place during stack
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-- checking operations. It causes infinite loops and other problems.
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with System.Storage_Elements;
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package System.Stack_Checking.Operations is
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pragma Preelaborate;
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procedure Update_Stack_Cache (Stack : Stack_Access);
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-- Set the stack cache for the current task. Note that this is only for
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-- optimization purposes, nothing can be assumed about the contents of the
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-- cache at any time, see Set_Stack_Info.
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--
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-- The stack cache should contain the bounds of the current task. But
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-- because the RTS is not aware of task switches, the stack cache may be
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-- incorrect. So when the stack pointer is not within the bounds of the
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-- stack cache, Stack_Check first update the cache (which is a costly
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-- operation hence the need of a cache).
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procedure Invalidate_Stack_Cache (Any_Stack : Stack_Access);
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-- Invalidate cache entries for the task T that owns Any_Stack. This causes
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-- the Set_Stack_Info function to be called during the next stack check
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-- done by T. This can be used to interrupt task T asynchronously.
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-- Stack_Check should be called in loops for this to work reliably.
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function Stack_Check (Stack_Address : System.Address) return Stack_Access;
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-- This version of Stack_Check should not be inlined
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procedure Notify_Stack_Attributes
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(Initial_SP : System.Address;
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Size : System.Storage_Elements.Storage_Offset);
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-- Register Initial_SP as the initial stack pointer value for the current
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-- task when it starts and Size as the associated stack area size. This
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-- should be called once, after the soft-links have been initialized and
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-- prior to the first "Stack_Check" call.
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private
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Cache : aliased Stack_Access := Null_Stack;
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pragma Export (C, Cache, "_gnat_stack_cache");
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pragma Export (C, Stack_Check, "_gnat_stack_check");
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end System.Stack_Checking.Operations;
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