Re: [PULL 00/51] Build system, i386 changes for 2023-09-07

[Daniel P . Berrangé]

On Fri, Sep 08, 2023 at 07:16:16PM +0200, Kevin Wolf wrote:
> Am 08.09.2023 um 18:11 hat Philippe Mathieu-Daudé geschrieben:
> > Hi Kevin,
> > 
> > On 8/9/23 17:01, Kevin Wolf wrote:
> > > Am 07.09.2023 um 17:44 hat Stefan Hajnoczi geschrieben:
> > > > Applied, thanks.
> > > > 
> > > > Please update the changelog at https://wiki.qemu.org/ChangeLog/8.2 for 
> > > > any user-visible changes.
> > > 
> > > Something in this has broken the build for me, it seems to be the
> > > linux-user binary that doesn't link any more:
> > > 
> > >    /usr/bin/ld: libqemu-x86_64-linux-user.fa.p/target_i386_cpu.c.o: in 
> > > function `cpu_x86_cpuid':
> > >    /home/kwolf/source/qemu/build-clang/../target/i386/cpu.c:6180: 
> > > undefined reference to `kvm_arch_get_supported_cpuid'
> > 
> > My patches. I can not reproduce so far,

Given the missing function name, I'm assuming the problem is this commit:

[quote]
Subject: [PULL 42/51] target/i386: Remove unused KVM stubs

From: Philippe Mathieu-Daudé <philmd@linaro.org>

All these functions:

 - kvm_arch_get_supported_cpuid()
 - kvm_has_smm(()
 - kvm_hyperv_expand_features()
 - kvm_set_max_apic_id()

are called after checking for kvm_enabled(), which is
false when KVM is not built. Since the compiler elides
these functions, their stubs are not used and can be
removed.
[/quote]

> Hm, ok. I can try to bisect it further then.
> 
> > What are your ./configure command options?
> 
> '/home/kwolf/source/qemu/configure' '--cc=clang' 
> '--target-list=x86_64-linux-user,x86_64-softmmu,arm-softmmu,aarch64-softmmu' 
> '--enable-debug' '--cxx=clang++' '--disable-blkio' 

--enable-debug results in "-O0" being used for optimization.

I bet this stops the compiler from eliding the functions
as claimed by the commit above. IOW, we do in fact still
need these stubs.


With regards,
Daniel
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