Re: Build failure on Windows

On 17-Dec-06, at 12:12 AM, Ian Lynagh wrote:

> Hi all,
>
> Is anyone else seeing a failure with the HEAD linking the stage2  
> GHC on
> Windows (XP Pro)? This is under cygwin, and I can build 6.6 fine.  
> Anyone
> got any idea what's going wrong?

 From looking at the code, my guess is that this is a severe case of  
Calling Convention Confusion.

GetWindowsDirectoryW and GetSystemDirectoryW are declared as ccall,  
and I think they should be stdcall like everything else.

As far as DeleteObject is concerned, Types.hs has a 'foreign import  
stdcall unsafe "windows.h &DeleteObject"'; there are two problems  
with this:

a) The stdcall modifier is ignored by GHC, the compiler generates a  
ref to DeleteObject, not DeleteObject@4 as it should. I think this is  
our link error.

GHC would need to look at the imported thing's FunPtr type to  
determine the argument size, and complain if a non-function is  
imported as "stdcall".

b) A pointer to a stdcall function (DeleteObject) is used where a  
pointer to a ccall function is expected (ForeignPtr finaliser).  
AFAICT, this is supposed to cause cause quite horrible crashes (stack  
corruption), and we should really be glad about that link error.

So, I think those Get*DirectoyW functions need to be stdcalled, and  
DeleteObject needs a ccalled wrapper in cbits.

I have no idea why things worked with ghc-6.6. Are all those  
functions unused in 6.6?


Hope that helps,

Wolfgang