Re: [Qemu-devel] [PULL 0/5] X86 patch queue, 2015-05-29

[Eduardo Habkost]

On Fri, May 29, 2015 at 07:57:16PM +0100, Peter Maydell wrote:
> On 29 May 2015 at 19:04, Eduardo Habkost <address@hidden> wrote:
> > The following changes since commit 2cc3bdbe2d3908f7a813d1c2d774cc2bf07746cd:
> >
> >   Merge remote-tracking branch 'remotes/armbru/tags/pull-block-2015-05-29' 
> > into staging (2015-05-29 15:32:15 +0100)
> >
> > are available in the git repository at:
> >
> >   git://github.com/ehabkost/qemu.git tags/x86-pull-request
> >
> > for you to fetch changes up to d032544e08ed07c66afd45ca8a8420ca202fab75:
> >
> >   arch_init: Drop target-x86_64.conf (2015-05-29 14:46:32 -0300)
> >
> > ----------------------------------------------------------------
> > X86 patch queue, 2015-05-29
> 
> Hi. I'm afraid this patchset provokes a lot of warnings from
> clang's undefined-behaviour sanitizer when we run make check:
> 
> /home/petmay01/linaro/qemu-for-merges/hw/intc/apic_common.c:314:55:
> runtime error: left shift of 1048575 by 12 places cannot be
> represented in type 'int'
> 
> This is because this:
> target-i386/cpu.h:#define MSR_IA32_APICBASE_BASE (0xfffff<<12)
> 
> is shifting a 1 into the sign bit of a signed integer. You need
> to write 0xfffffU to force an unsigned shift here.
> 
> (The undef sanitizer is one of those things I don't really
> expect submaintainers to run but which I have enabled for
> my build process. At the moment we're almost clean for a
> make check run, so I'm keen to avoid introducing new warnings.)

I will submit a fix and send a new pull request later. Thanks!

(I will also add a new build configuration to my setup using clang and
-fsanitize=undefined)

-- 
Eduardo