Re: [PATCH v4 0/3] Enable clang build on Windows

[Brian Cain <brian.cain@oss.qualcomm.com>]

On 1/11/2025 4:08 PM, Stefan Weil via wrote:
> Am 10.01.25 um 21:33 schrieb Pierrick Bouvier:
>> For now, it was only possible to build plugins using GCC on Windows. 
>> However,
>> windows-aarch64 only supports Clang.
>> This biggest roadblock was to get rid of gcc_struct attribute, which 
>> is not
>> supported by Clang. After investigation, we proved it was safe to 
>> drop it.
>>
>> Built and tested on Windows (all msys env)/Linux/MacOS for x86_64 and 
>> aarch64
>> hosts.
>>
>> v1 contained warning fixes and various bits that have been upstreamed 
>> already.
>> The only bits left in this series are the gcc_struct removal, and 
>> fixing the
>> plugins build with clang.
>>
>> This series is for 10.0, as we decided to not include the gcc_struct 
>> removal is
>> 9.2 release.
>>
>> All patches are now reviewed, so this series can be pulled. I'll 
>> report that to
>> MSYS2 too, so we can enable clang environments for QEMU.
>>
>> v1: 
>> https://patchew.org/QEMU/20241031040426.772604-1-pierrick.bouvier@linaro.org/
>>
>> v2:
>> - drop attribute gcc_struct instead of using -mno-ms-bitfields option
>> - add a section about bitfields in documentation
>>
>> v3:
>> - explain why gcc_struct attribute matters in packed structs in 
>> commit message
>> - reword the bitfields documentation with suggestions given
>>
>> v4:
>> - edit for bitfields doc requested by Philippe
>>
>> Pierrick Bouvier (3):
>>    win32: remove usage of attribute gcc_struct
>>    docs/devel/style: add a section about bitfield, and disallow them for
>>      packed structures
>>    plugins: enable linking with clang/lld
>>
>>   docs/devel/style.rst                      | 20 +++++++++++++++++++
>>   meson.build                               |  6 +++---
>>   include/qemu/compiler.h                   |  7 +------
>>   scripts/cocci-macro-file.h                |  6 +-----
>>   subprojects/libvhost-user/libvhost-user.h |  6 +-----
>>   contrib/plugins/meson.build               |  2 +-
>>   plugins/meson.build                       | 24 +++++++++++++++++++----
>>   tests/tcg/plugins/meson.build             |  3 +--
>>   8 files changed, 48 insertions(+), 26 deletions(-)
>
> This nice series allows building QEMU for Windows with the LLVM cross 
> compiler on my ARM64 machine, so you can add

Is this toolchain available publicly or did you build it yourself?  It 
would be handy if there were a linux x86_64 hosted cross-toolchain that 
can target Windows-aarch64.  Or linux aarch64 hosted would be pretty 
good, too.

Is there an MSYS2 or other distributor that provides windows-aarch64 
builds of the glib and other library dependencies?

>
> Tested-by: Stefan Weil <sw@weilnetz.de>
>
> I only needed a trivial additional fix in scripts/nsis.py for `make 
> installer` because the usual GNU objdump and the LLVM objdump (or the 
> cross x86_64-w64-mingw32-objdump in my test) produce slightly 
> different output (indentation with \t, indentation with four spaces). 
> I'll prepare a patch which eliminates the need for objdump, so no 
> intermediate fix is needed for this.
>
> Stefan W.
>