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Diffstat (limited to 'gcc/ada/s-stache.ads')
| -rw-r--r-- | gcc/ada/s-stache.ads | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/gcc/ada/s-stache.ads b/gcc/ada/s-stache.ads new file mode 100644 index 00000000000..d95c7021a54 --- /dev/null +++ b/gcc/ada/s-stache.ads @@ -0,0 +1,107 @@ +------------------------------------------------------------------------------ +-- -- +-- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS -- +-- -- +-- S Y S T E M . S T A C K _ C H E C K I N G -- +-- -- +-- S p e c -- +-- -- +-- $Revision: 1.6 $ +-- -- +-- Copyright (C) 1999-2001 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- -- +-- 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, 59 Temple Place - Suite 330, Boston, -- +-- MA 02111-1307, USA. -- +-- -- +-- 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. -- +-- -- +-- GNARL was developed by the GNARL team at Florida State University. It is -- +-- now maintained by Ada Core Technologies Inc. in cooperation with Florida -- +-- State University (http://www.gnat.com). -- +-- -- +------------------------------------------------------------------------------ + +-- This package provides a system-independent implementation of stack +-- checking using comparison with stack base and limit. + +with System.Storage_Elements; + +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. + +package System.Stack_Checking is + type Stack_Info is record + Limit : System.Address := System.Null_Address; + Base : System.Address := System.Null_Address; + Size : System.Storage_Elements.Storage_Offset := 0; + end record; + -- This record may be part of a larger data structure like the + -- task control block in the tasking case. + -- This specific layout has the advantage of being compatible with the + -- Intel x86 BOUNDS instruction. + + type Stack_Access is access all Stack_Info; + -- Unique local storage associated with a specific task. This storage is + -- used for the stack base and limit, and is returned by Checked_Self. + -- Only self may write this information, it may be read by any task. + -- At no time the address range Limit .. Base (or Base .. Limit for + -- upgrowing stack) may contain any address that is part of another stack. + -- The Stack_Access may be part of a larger data structure. + + Multi_Processor : constant Boolean := False; -- Not supported yet + + ---------------------- + -- Client Interface -- + ---------------------- + + procedure Set_Stack_Size + (Stack_Size : System.Storage_Elements.Storage_Offset); + -- Specify the stack size for the current task. + + 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. + + 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. + +private + + Null_Stack_Info : aliased Stack_Info := + (Limit => System.Null_Address, + Base => System.Null_Address, + Size => 0); + -- Use explicit assignment to avoid elaboration code (call to _init_proc). + + Null_Stack : constant Stack_Access := Null_Stack_Info'Access; + -- Stack_Access value that will return a Stack_Base and Stack_Limit + -- that fail any stack check. + + 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; |