------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- -- -- -- 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 -- -- -- -- S p e c -- -- -- -- Copyright (C) 1999-2009, Free Software Foundation, Inc. -- -- -- -- GNARL is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- . -- -- -- -- GNARL was developed by the GNARL team at Florida State University. -- -- Extensive contributions were provided by Ada Core Technologies, Inc. -- -- -- ------------------------------------------------------------------------------ -- This package provides a implementation of stack checking operations using -- comparison with stack base and limit. pragma Restrictions (No_Elaboration_Code); -- We want to guarantee the absence of elaboration code because the binder -- does not handle references to this package. pragma Polling (Off); -- Turn off polling, we do not want polling to take place during stack -- checking operations. It causes infinite loops and other problems. with System.Storage_Elements; package System.Stack_Checking.Operations is pragma Preelaborate; procedure Update_Stack_Cache (Stack : Stack_Access); -- Set the stack cache for the current task. Note that this is only for -- optimization purposes, nothing can be assumed about the contents of the -- cache at any time, see Set_Stack_Info. -- -- The stack cache should contain the bounds of the current task. But -- because the RTS is not aware of task switches, the stack cache may be -- incorrect. So when the stack pointer is not within the bounds of the -- stack cache, Stack_Check first update the cache (which is a costly -- operation hence the need of a cache). procedure Invalidate_Stack_Cache (Any_Stack : Stack_Access); -- Invalidate cache entries for the task T that owns Any_Stack. This causes -- the Set_Stack_Info function to be called during the next stack check -- done by T. This can be used to interrupt task T asynchronously. -- Stack_Check should be called in loops for this to work reliably. function Stack_Check (Stack_Address : System.Address) return Stack_Access; -- This version of Stack_Check should not be inlined procedure Notify_Stack_Attributes (Initial_SP : System.Address; Size : System.Storage_Elements.Storage_Offset); -- Register Initial_SP as the initial stack pointer value for the current -- task when it starts and Size as the associated stack area size. This -- should be called once, after the soft-links have been initialized and -- prior to the first "Stack_Check" call. private Cache : aliased Stack_Access := Null_Stack; pragma Export (C, Cache, "_gnat_stack_cache"); pragma Export (C, Stack_Check, "_gnat_stack_check"); end System.Stack_Checking.Operations;