diff options
Diffstat (limited to 'gcc/ada/s-stache.adb')
| -rw-r--r-- | gcc/ada/s-stache.adb | 232 |
1 files changed, 1 insertions, 231 deletions
diff --git a/gcc/ada/s-stache.adb b/gcc/ada/s-stache.adb index a784ed154cb..738e3eeb67b 100644 --- a/gcc/ada/s-stache.adb +++ b/gcc/ada/s-stache.adb @@ -6,7 +6,7 @@ -- -- -- B o d y -- -- -- --- Copyright (C) 1999-2003 Free Software Foundation, Inc. -- +-- Copyright (C) 1999-2004 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- -- @@ -31,235 +31,5 @@ -- -- ------------------------------------------------------------------------------ -with Ada.Exceptions; - -with System.Storage_Elements; use System.Storage_Elements; -with System.Parameters; use System.Parameters; -with System.Soft_Links; -with System.CRTL; - package body System.Stack_Checking is - - Kilobyte : constant := 1024; - - function Set_Stack_Info (Stack : 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. - - -- 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. - - -- 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. - - -- The following constants should be imported from some system-specific - -- constants package. The constants must be static for performance reasons. - - ---------------------------- - -- Invalidate_Stack_Cache -- - ---------------------------- - - procedure Invalidate_Stack_Cache (Any_Stack : Stack_Access) is - pragma Warnings (Off, Any_Stack); - begin - Cache := Null_Stack; - end Invalidate_Stack_Cache; - - -------------------- - -- Set_Stack_Info -- - -------------------- - - function Set_Stack_Info - (Stack : access Stack_Access) return Stack_Access - is - type Frame_Mark is null record; - Frame_Location : Frame_Mark; - Frame_Address : constant Address := Frame_Location'Address; - - My_Stack : Stack_Access; - Limit_Chars : System.Address; - Limit : Integer; - - begin - -- The order of steps 1 .. 3 is important, see specification. - - -- 1) Get the Stack_Access value for the current task - - My_Stack := Soft_Links.Get_Stack_Info.all; - - if My_Stack.Base = Null_Address then - - -- First invocation, initialize based on the assumption that - -- there are Environment_Stack_Size bytes available beyond - -- the current frame address. - - if My_Stack.Size = 0 then - My_Stack.Size := Storage_Offset (Default_Env_Stack_Size); - - -- When the environment variable GNAT_STACK_LIMIT is set, - -- set Environment_Stack_Size to that number of kB. - - Limit_Chars := System.CRTL.getenv ("GNAT_STACK_LIMIT" & ASCII.NUL); - - if Limit_Chars /= Null_Address then - Limit := System.CRTL.atoi (Limit_Chars); - - if Limit >= 0 then - My_Stack.Size := Storage_Offset (Limit) * Kilobyte; - end if; - end if; - end if; - - My_Stack.Base := Frame_Address; - - if Stack_Grows_Down then - - -- Prevent wrap-around on too big stack sizes - - My_Stack.Limit := My_Stack.Base - My_Stack.Size; - - if My_Stack.Limit > My_Stack.Base then - My_Stack.Limit := Address'First; - end if; - - else - My_Stack.Limit := My_Stack.Base + My_Stack.Size; - - -- Prevent wrap-around on too big stack sizes - - if My_Stack.Limit < My_Stack.Base then - My_Stack.Limit := Address'Last; - end if; - end if; - end if; - - -- 2) Set Stack.all to the value obtained in 1) - - Stack.all := My_Stack; - - -- 3) Optionally Poll to check for asynchronous abort - - if Soft_Links.Check_Abort_Status.all /= 0 then - raise Standard'Abort_Signal; - end if; - - return My_Stack; -- Never trust the cached value, but return local copy! - end Set_Stack_Info; - - -------------------- - -- Set_Stack_Size -- - -------------------- - - -- Specify the stack size for the current frame. - - procedure Set_Stack_Size - (Stack_Size : System.Storage_Elements.Storage_Offset) - is - My_Stack : Stack_Access; - Frame_Address : constant System.Address := My_Stack'Address; - - begin - My_Stack := Stack_Check (Frame_Address); - - if Stack_Grows_Down then - My_Stack.Limit := My_Stack.Base - Stack_Size; - else - My_Stack.Limit := My_Stack.Base + Stack_Size; - end if; - end Set_Stack_Size; - - ----------------- - -- Stack_Check -- - ----------------- - - function Stack_Check - (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)) - 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! - - begin - if (Stack_Grows_Down and then - (not (Frame_Address <= My_Stack.Base))) - or else - (not Stack_Grows_Down and then - (not (Frame_Address >= My_Stack.Base))) - then - -- The returned Base is lower than the stored one, - -- so assume that the original one wasn't right and use the - -- current Frame_Address as new one. This allows initializing - -- Base with the Frame_Address as approximation. - -- During initialization the Frame_Address will be close to - -- the stack base anyway: the difference should be compensated - -- for in the stack reserve. - - My_Stack.Base := Frame_Address; - end if; - - 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, - Message => "stack overflow detected"); - end if; - - return My_Stack; - end Full_Check; - end Stack_Check; - - ------------------------ - -- Update_Stack_Cache -- - ------------------------ - - procedure Update_Stack_Cache (Stack : Stack_Access) is - begin - if not Multi_Processor then - Cache := Stack; - end if; - end Update_Stack_Cache; - end System.Stack_Checking; |