[PATCH] Adjust _Unwind_Word in unwind.h to version in libgcc.

[Stefan Liebler]

Hi,

I get the following warning while building glibc on s390-32 with gcc 
option -mzarch:

In file included from unwind.c:26:0:
unwind.c: In function 'unwind_stop':
../sysdeps/s390/jmpbuf-unwind.h:37:10: error: cast to pointer from 
integer of different size [-Werror=int-to-pointer-cast]
           (void *) (_Unwind_GetCFA  (_context) \
           ^
../sysdeps/s390/jmpbuf-unwind.h:51:17: note: in definition of macro 
'_JMPBUF_UNWINDS_ADJ'
    ((uintptr_t) (_address) - (_adj) < _jmpbuf_sp (_jmpbuf) - (_adj))
                  ^
unwind.c:62:12: note: in expansion of macro '_JMPBUF_CFA_UNWINDS_ADJ'
        || ! _JMPBUF_CFA_UNWINDS_ADJ (buf->cancel_jmp_buf[0].jmp_buf, 
context,

Building on s390-32 in esa-mode or s390-64 is fine.

_Unwind_GetCFA returns an _Unwind_Word which is an unsigned
with a size of 4 bytes on s390-32 (esa-mode) and 8 bytes on s390-64.
On s390-32 (zarch-mode), _Unwind_Word has a size of 8 bytes, too.

_Unwind_Word is defined in sysdeps/generic/unwind.h as
typedef unsigned _Unwind_Word __attribute__((__mode__(__word__)));

In libgcc unwind header (<gcc-src>/libgcc/unwind-generic.h) this typedef 
has changed to
"typedef unsigned _Unwind_Word 
__attribute__((__mode__(__unwind_word__)));" in June 2008.
With this mode, _Unwind_Word has a size of 4 bytes on s390-32 (zarch-mode).
The same change applies to _Unwind_Sword.
Thus this patch updates the unwind header according to these changes.

Afterwards, the int-to-pointer-cast-warning is gone away on s390-32 
(zarch-mode) and the testsuite runs with the same test-failures as 
s390-32 (esa-mode) plus FAIL: c++-types-check. Here register_t is 
expected to has a size of 4 bytes, but it has a size of 8 bytes
due to
posix/sys/types.h:205:typedef int register_t __attribute__ ((__mode__ 
(__word__)));

The libgcc-patch for gcc 4.4 can be found here:
"[PATCH, spu, unwind] Remove attribute ((mode (word))) from unwind.h"
https://gcc.gnu.org/ml/gcc-patches/2008-06/msg00969.html

Ok to commit?

Bye
Stefan

2015-07-28  Stefan Liebler  <stli@linux.vnet.ibm.com>

	* sysdeps/generic/unwind.h
	(_Unwind_Word): Use __mode__(__unwind_word__)
	instead of __mode__(__word__).
	(_Unwind_Sword): Likewise.
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