Re: [Qemu-devel] Hacks for building on gcc 7 / Fedora 26

[Dr. David Alan Gilbert]

* Eric Blake (address@hidden) wrote:
> On 07/17/2017 11:46 AM, Dr. David Alan Gilbert wrote:
> 
> >> +++ w/hw/usb/bus.c
> >> @@ -407,8 +407,9 @@ void usb_register_companion(const char *masterbus,
> >> USBPort *ports[],
> >>  void usb_port_location(USBPort *downstream, USBPort *upstream, int portnr)
> >>  {
> >>      if (upstream) {
> >> -        snprintf(downstream->path, sizeof(downstream->path), "%s.%d",
> >> -                 upstream->path, portnr);
> >> +        int l = snprintf(downstream->path, sizeof(downstream->path),
> >> "%s.%d",
> >> +                         upstream->path, portnr);
> >> +        assert(l < sizeof(downstream->path));
> > 
> > You may find this doesn't help in some windows builds;  the assert
> > functions aren't always marked as noreturn (because they pop up a dialog
> > that asks you whether you want to run into a debugger etc).
> 
> How would it not help?  Are we using gcc 7 on windows builds?  Adding
> the assert is enough to shut up new gcc; old gcc was already silent; and
> if mingw is still on old gcc, it doesn't matter whether assert() is
> marked noreturn for what this patch is doing.

address@hidden ~]$ x86_64-w64-mingw32-gcc -v
Using built-in specs.
COLLECT_GCC=/usr/bin/x86_64-w64-mingw32-gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-w64-mingw32/7.1.0/lto-wrapper
Target: x86_64-w64-mingw32
Configured with: ../configure --prefix=/usr --bindir=/usr/bin 
--includedir=/usr/include --mandir=/usr/share/man --infodir=/usr/share/info 
--datadir=/usr/share --build=x86_64-redhat-linux-gnu 
--host=x86_64-redhat-linux-gnu --with-gnu-as --with-gnu-ld --verbose 
--without-newlib --disable-multilib --disable-plugin --with-system-zlib 
--disable-nls --without-included-gettext --disable-win32-registry 
--enable-languages=c,c++,objc,obj-c++,fortran 
--with-bugurl=http://bugzilla.redhat.com/bugzilla --with-cloog 
--enable-threads=posix --enable-libgomp --target=x86_64-w64-mingw32 
--with-sysroot=/usr/x86_64-w64-mingw32/sys-root 
--with-gxx-include-dir=/usr/x86_64-w64-mingw32/sys-root/mingw/include/c++
Thread model: posix
gcc version 7.1.0 20170502 (Fedora MinGW 7.1.0-1.fc26) (GCC)

Dave
> 
> -- 
> Eric Blake, Principal Software Engineer
> Red Hat, Inc.           +1-919-301-3266
> Virtualization:  qemu.org | libvirt.org
> 



--
Dr. David Alan Gilbert / address@hidden / Manchester, UK