-- --
-- S p e c --
-- --
--- Copyright (C) 1999-2005 Free Software Foundation, Inc. --
+-- 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 2, or (at your option) any later ver- --
--- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
+-- 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. See the GNU General Public License --
--- for more details. You should have received a copy of the GNU General --
--- Public License distributed with GNARL; see file COPYING. If not, write --
--- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
--- Boston, MA 02110-1301, USA. --
+-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
--- As a special exception, if other files instantiate generics from this --
--- unit, or you link this unit with other files to produce an executable, --
--- this unit does not by itself cause the resulting executable to be --
--- covered by the GNU General Public License. This exception does not --
--- however invalidate any other reasons why the executable file might be --
--- covered by the GNU Public License. --
+-- 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 --
+-- <http://www.gnu.org/licenses/>. --
-- --
-- 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.
+-- 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.
+-- 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.
+ -- 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.
+ -- 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.
+ -- This version of Stack_Check should not be inlined
-private
+ 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");
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