Re: [Qemu-devel] [PATCH] win64: perform correct setjmp calls

["Pavel Dovgaluk" <Pavel.Dovgaluk@ispras.ru>]

> From: Stefan Weil [mailto:sw@weilnetz.de]
> Am 09.02.2015 um 09:07 schrieb Pavel Dovgaluk:
> >> From: Stefan Weil [mailto:sw@weilnetz.de]
> >> Am 09.02.2015 um 08:55 schrieb Pavel Dovgalyuk:
> >>> On w64, setjmp is implemented by _setjmp which needs a second parameter.
> >>> This parameter should be NULL to allow using longjump from generated code.
> >>> This patch replaces all usages of setjmp.h with new header files which
> >>> replaces setjmp with _setjmp function on win64 platform.
> >>>
> >>> Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
> >> Please have a look at include/sysemu/os-win32.h. I think that your patch
> >> is not needed because the current code already uses _setjmp.
> > Right, but some of the files (e.g. include/qom/cpu.h) include setjmp.h directly.
> > Then we have the following for compiling cpu-exec.c:
> >
> > cpu-exec.c:
> > ...
> > os-win32.h
> > ...
> > setjmp.h
> > ...
> >
> > In this situation cpu-exec will call incorrect setjmp function.
> >
> > Pavel Dovgalyuk
> 
> 
> It won't call the wrong setjmp function, at least not in my tests.
> cpu-exec.c gets the setjmp declaration from os-win32.h. Without it, QEMU
> would be unusable because it would crash very soon during the emulation.
> 
> Do you see problems caused by a wrong setjmp with latest QEMU? If yes:
> which build environment do you use (host, compiler, version of MinGW*)?

Yes, I've got the problems. To verify the correctness of the call I disassembled
cpu-exec.o and found that setjmp is called with second parameter not equal to zero.

I'm using Cygwin environment and packages from here: http://win-builds.org/
My host OS is Windows 7x64 and the compiler is x86_64-w64-mingw32-gcc.exe (GCC) 4.8.3

Pavel Dovgalyuk