Re: Cross-compilation artifact is broken

["Alex Bennée" <alex.bennee@linaro.org>]

Daniel P. Berrangé <berrange@redhat.com> writes:

> On Wed, Mar 12, 2025 at 02:05:09PM +0000, Daniel P. Berrangé wrote:
>> On Wed, Mar 12, 2025 at 03:52:45PM +0200, Konstantin Kostiuk wrote:
>> > Hi All,
>> > 
>> > I cross-compiled qemu-ga from current master branch
>> > (825b96dbcee23d134b691fc75618b59c5f53da32) and found strange behavior.
>> > 
>> > Configure CLI:
>> > ./configure --disable-docs --disable-system --disable-user
>> > --cross-prefix=x86_64-w64-mingw32- --enable-guest-agent
>> > --disable-guest-agent-msi --disable-qga-vss
>> > Build CLI:
>> > make -j8 qemu-ga
>> > 
>> > Linker wrote the following information but exited with 0 code:
>> > 
>> > /usr/lib/gcc/x86_64-w64-mingw32/14.2.0/../../../../x86_64-w64-mingw32/bin/ld:
>> > qga/qemu-ga.exe:/4: section below image base
>> > /usr/lib/gcc/x86_64-w64-mingw32/14.2.0/../../../../x86_64-w64-mingw32/bin/ld:
>> > qga/qemu-ga.exe:/24: section below image base
>> > 
>> > As a result, this binary failed to start on Windows without any details,
>> > just a message that the application is not compatible. I also tried to run
>> > it with wine and got the error:
>> > 
>> > wine: failed to start
>> > L"Z:\\home\\user\\Documents\\repos\\qemu\\build\\qga\\qemu-ga.exe"
>> > Application could not be started, or no application associated with the
>> > specified file.
>> > ShellExecuteEx failed: Bad EXE format for
>> > Z:\home\user\Documents\repos\qemu\build\qga\qemu-ga.exe.
>> > 
>> > I bisected the tree and found the commit that caused the problem:
>> > https://gitlab.com/qemu-project/qemu/-/commit/563b1a35ed1f1151505d4fe5f723827d1b3fd4bc
>> > 
>> > Adding --disable-split-debug to the configure CLI fixes the issue.
>> > 
>> > $ x86_64-w64-mingw32-gcc --version
>> > x86_64-w64-mingw32-gcc (GCC) 14.2.0
>> > 
>> > My question is, is this expected behavior or is this a bug?
>> 
>> Your configure args don't include "--enable-debug", so I would
>> not have expected -gsplit-dwarf to have been enabled, so I'm
>> surprised that commit casued a problem.
>
> Hmm it appears that the meson  "get_option('debug')" is entirely
> unconnected to QEMU's --enable-debug configure flag, which I did
> not realize.
>
> IOW, we've got -gsplit-dwarf enabled by default for everyone
> building QEMU, which feels dubious. IMHO only an explicit
> --enable-debug configure arg should have triggered it.

--enable-debug is more than debug info, --enable-debug-info is enabled
by default. If you build with --disable-debug-info then -gsplit-dwarf
won't be applied.

>
> In addition since its breaking Windows builds, it appears we
> need to block its usage on Windows.
>
>
> With regards,
> Daniel

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro