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Commit 7a56c3bc by Eric Botcazou Committed by Arnaud Charlet
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s-stchop-vxworks.adb: 

2007-04-06  Eric Botcazou <botcazou@adacore.com>

	* s-stchop-vxworks.adb: 
	(Stack_Check): Raise Storage_Error if the argument has wrapped around.

From-SVN: r123605
parent fc879b8f
Showing with 57 additions and 45 deletions
gcc/ada/s-stchop-vxworks.adb
......@@ -6,7 +6,7 @@
-- --
-- B o d y --
-- --
-- Copyright (C) 1999-2006 Free Software Foundation, Inc. --
-- Copyright (C) 1999-2006, 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- --
......@@ -49,38 +49,40 @@ with System.OS_Interface;
package body System.Stack_Checking.Operations is
-- In order to have stack checking working appropriately on
-- VxWorks we need to extract the stack size information from the
-- VxWorks kernel itself. It means that the library for showing
-- task-related information needs to be linked into the VxWorks
-- system, when using stack checking. The TaskShow library can be
-- linked into the VxWorks system by either:
-- In order to have stack checking working appropriately on VxWorks we need
-- to extract the stack size information from the VxWorks kernel itself. It
-- means that the library for showing task-related information needs to be
-- linked into the VxWorks system, when using stack checking. The TaskShow
-- library can be linked into the VxWorks system by either:
-- * defining INCLUDE_SHOW_ROUTINES in config.h when using
-- configuration header files, or
-- * selecting INCLUDE_TASK_SHOW when using the Tornado project
-- facility.
function Set_Stack_Info (Stack : access Stack_Access) return Stack_Access;
function Set_Stack_Info
(Stack : not null access Stack_Access) return Stack_Access;
-- The function Set_Stack_Info is the actual function that updates
-- the cache containing a pointer to the Stack_Info. It may also
-- be used for detecting asynchronous abort in combination with
-- Invalidate_Self_Cache.
-- The function Set_Stack_Info is the actual function that updates the
-- cache containing a pointer to the Stack_Info. It may also be used for
-- detecting asynchronous abort in combination with Invalidate_Self_Cache.
-- Set_Stack_Info should do the following things in order:
-- 1) Get the Stack_Access value for the current task
-- 2) Set Stack.all to the value obtained in 1)
-- 3) Optionally Poll to check for asynchronous abort
-- This order is important because if at any time a write to
-- the stack cache is pending, that write should be followed
-- by a Poll to prevent loosing signals.
-- This order is important because if at any time a write to the stack
-- cache is pending, that write should be followed by a Poll to prevent
-- loosing signals.
-- Note: This function must be compiled with Polling turned off
-- Note: on systems like VxWorks and OS/2 with real thread-local storage,
-- Set_Stack_Info should return an access value for such local
-- storage. In those cases the cache will always be up-to-date.
-- Fix examples??? Linux???
-- The following constants should be imported from some system-specific
-- constants package. The constants must be static for performance reasons.
......@@ -100,9 +102,8 @@ package body System.Stack_Checking.Operations is
--------------------
function Set_Stack_Info
(Stack : access Stack_Access) return Stack_Access
(Stack : not null access Stack_Access) return Stack_Access
is
-- Task descriptor that is handled internally by the VxWorks kernel
type Td_Events_Storage is array (1 .. 4) of Interfaces.C.int;
......@@ -131,8 +132,9 @@ package body System.Stack_Checking.Operations is
-- This VxWorks procedure fills in a specified task descriptor
-- for a specified task.
procedure TaskInfoGet (T_Id : System.OS_Interface.t_id;
Task_Desc : access Task_Descriptor);
procedure TaskInfoGet
(T_Id : System.OS_Interface.t_id;
Task_Desc : not null access Task_Descriptor);
pragma Import (C, TaskInfoGet, "taskInfoGet");
My_Stack : Stack_Access;
......@@ -147,12 +149,12 @@ package body System.Stack_Checking.Operations is
if My_Stack.Base = Null_Address then
-- First invocation. Ask the VxWorks kernel about stack
-- values.
-- First invocation. Ask the VxWorks kernel about stack values
TaskInfoGet (System.OS_Interface.taskIdSelf, Task_Desc'Access);
My_Stack.Size := System.Storage_Elements.Storage_Offset
(Task_Desc.Td_StackSize);
My_Stack.Size :=
System.Storage_Elements.Storage_Offset (Task_Desc.Td_StackSize);
My_Stack.Base := Task_Desc.Td_PStackBase;
My_Stack.Limit := Task_Desc.Td_PStackLimit;
......@@ -168,7 +170,9 @@ package body System.Stack_Checking.Operations is
raise Standard'Abort_Signal;
end if;
return My_Stack; -- Never trust the cached value, but return local copy!
-- Never trust the cached value, return local copy!
return My_Stack;
end Set_Stack_Info;
-----------------
......@@ -179,42 +183,50 @@ package body System.Stack_Checking.Operations is
(Stack_Address : System.Address) return Stack_Access
is
type Frame_Marker is null record;
Marker : Frame_Marker;
Cached_Stack : constant Stack_Access := Cache;
Frame_Address : constant System.Address := Marker'Address;
begin
-- This function first does a "cheap" check which is correct
-- if it succeeds. In case of failure, the full check is done.
-- Ideally the cheap check should be done in an optimized manner,
-- or be inlined.
if (Stack_Grows_Down and then
(Frame_Address <= Cached_Stack.Base
and
Stack_Address > Cached_Stack.Limit))
or else
(not Stack_Grows_Down and then
(Frame_Address >= Cached_Stack.Base
and
Stack_Address < Cached_Stack.Limit))
-- The parameter may have wrapped around in System.Address arithmetics.
-- In that case, we have no other choices than raising the exception.
if (Stack_Grows_Down and then Stack_Address > Frame_Address)
or else (not Stack_Grows_Down and then Stack_Address < Frame_Address)
then
Ada.Exceptions.Raise_Exception
(E => Storage_Error'Identity,
Message => "stack overflow detected");
end if;
-- This function first does a "cheap" check which is correct if it
-- succeeds. In case of failure, the full check is done. Ideally the
-- cheap check should be done in an optimized manner, or be inlined.
if (Stack_Grows_Down
and then Frame_Address <= Cached_Stack.Base
and then Stack_Address > Cached_Stack.Limit)
or else (not Stack_Grows_Down
and then Frame_Address >= Cached_Stack.Base
and then Stack_Address < Cached_Stack.Limit)
then
-- Cached_Stack is valid as it passed the stack check
return Cached_Stack;
end if;
Full_Check :
declare
My_Stack : constant Stack_Access := Set_Stack_Info (Cache'Access);
-- At this point Stack.all might already be invalid, so
-- it is essential to use our local copy of Stack!
-- At this point Stack.all might already be invalid, so it is
-- essential to use our local copy of Stack!
begin
if (Stack_Grows_Down and then
Stack_Address < My_Stack.Limit)
or else
(not Stack_Grows_Down and then
Stack_Address > My_Stack.Limit)
if (Stack_Grows_Down
and then Stack_Address < My_Stack.Limit)
or else (not Stack_Grows_Down
and then Stack_Address > My_Stack.Limit)
then
Ada.Exceptions.Raise_Exception
(E => Storage_Error'Identity,
......
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