Re: [PATCH 12/12] meson: link ARM and RISC-V into qemu-system

Thanks, a lot simpler, you can pick my patches(you think is good) into your
patch series and repost as a new version, so the review process is easier.

On Tue, Aug 25, 2026 at 12:20 AM Pierrick Bouvier <
[email protected]> wrote:
>
> On 8/23/2026 8:07 AM, Yonggang Luo wrote:
> > - Build qemu-system (and qemu-systemw on Windows) from aarch64
> >   common/system objects plus RISC-V arch objects taken from the
> >   existing riscv64 lib.
> > - Pull 32-bit TargetInfo and 32-only boards from the arm/riscv32
> >   libs so hw/arm and target/riscv are not compiled twice.
> > - Skip linking qemu-system-{arm,aarch64,riscv32,riscv64} and the
> >   Windows *w variants; symlink those names to qemu-system so
> >   argv[0] still selects TargetInfo.
> >
> > Signed-off-by: Yonggang Luo <[email protected]>
> > ---
> >  meson.build | 156 +++++++++++++++++++++++++++++++++++++++++++++++++---
> >  1 file changed, 147 insertions(+), 9 deletions(-)
> >
> > diff --git a/meson.build b/meson.build
> > index 449d50f2983..b4f435f6a22 100644
> > --- a/meson.build
> > +++ b/meson.build
> > @@ -4250,6 +4250,10 @@ endif
> >
> >  traceable = []
> >  emulators = {}
> > +target_softmmu = {}
> > +combo_softmmu = ['aarch64-softmmu', 'arm-softmmu', 'riscv32-softmmu',
'riscv64-softmmu']
> > +have_qemu_system_combo = ('aarch64-softmmu' in target_dirs
> > +                          and 'riscv64-softmmu' in target_dirs)
> >  foreach target : target_dirs
> >    config_target = config_target_mak[target]
> >    target_name = config_target['TARGET_NAME']
> > @@ -4399,20 +4403,37 @@ foreach target : target_dirs
> >                   c_args: c_args,
> >                   build_by_default: false)
> >
> > +  if target in combo_softmmu
> > +    target_softmmu += {target: {
> > +      'lib': lib,
> > +      'arch_srcs': arch_srcs,
> > +      'arch_deps': arch_deps,
> > +      'c_args': c_args,
> > +      'link_args': link_args,
> > +      'target_stubs': target_stubs,
> > +      'main_rs': main_rs,
> > +      'config_target': config_target,
> > +      'target_base_arch': target_base_arch,
> > +    }}
> > +  endif
> > +
> >    if target.endswith('-softmmu')
> > -    execs = [{
> > -      'name': 'qemu-system-' + target_name,
> > -      'win_subsystem': 'console',
> > -      'sources': [main_rs, files('system/main.c')],
> > -      'dependencies': [sdl, target_stubs],
> > -    }]
> > -    if host_os == 'windows' and (sdl.found() or gtk.found())
> > +    execs = []
> > +    if not (have_qemu_system_combo and target in combo_softmmu)
> >        execs += [{
> > -        'name': 'qemu-system-' + target_name + 'w',
> > -        'win_subsystem': 'windows',
> > +        'name': 'qemu-system-' + target_name,
> > +        'win_subsystem': 'console',
> >          'sources': [main_rs, files('system/main.c')],
> >          'dependencies': [sdl, target_stubs],
> >        }]
> > +      if host_os == 'windows' and (sdl.found() or gtk.found())
> > +        execs += [{
> > +          'name': 'qemu-system-' + target_name + 'w',
> > +          'win_subsystem': 'windows',
> > +          'sources': [main_rs, files('system/main.c')],
> > +          'dependencies': [sdl, target_stubs],
> > +        }]
> > +      endif
> >      endif
> >      if get_option('fuzzing')
> >        specific_fuzz = specific_fuzz_ss.apply(config_target, strict:
false)
> > @@ -4481,6 +4502,123 @@ foreach target : target_dirs
> >    endforeach
> >  endforeach
> >
> > +# Combined ARM + RISC-V system emulator (32 and 64).
> > +# Common/system objects come from aarch64. RISC-V arch objects come
> > +# from the existing riscv64 lib. 32-bit TargetInfo and 32-only boards
> > +# come from the arm/riscv32 libs. Per-target qemu-system-* names are
> > +# symlinks to qemu-system (argv[0] selects TargetInfo).
> > +if have_qemu_system_combo
> > +  a64 = target_softmmu['aarch64-softmmu']
> > +  rv = target_softmmu['riscv64-softmmu']
> > +  extra_objs = []
> > +  target_info_def = files('target-info-def.c')
> > +  foreach spec : [[common_ss, common_all], [system_ss, libsystem]]
> > +    rv_src = spec[0].apply(rv['config_target'], strict: false)
> > +    a64_src = spec[0].apply(a64['config_target'], strict: false)
> > +    extra = []
> > +    foreach f : rv_src.sources()
> > +      if f not in a64_src.sources() and not
f.full_path().endswith('_stubs.c')
> > +        extra += f
> > +      endif
> > +    endforeach
> > +    if extra.length() > 0
> > +      extra_objs += spec[1].extract_objects(extra)
> > +    endif
> > +  endforeach
> > +  rv_base = rv['target_base_arch']
> > +  if rv_base in target_common_arch_libs
> > +    src = target_common_arch[rv_base].apply(rv['config_target'],
strict: false)
> > +    extra_objs +=
target_common_arch_libs[rv_base].extract_objects(src.sources())
> > +  endif
> > +  if rv_base in target_common_system_arch_libs
> > +    src =
target_common_system_arch[rv_base].apply(rv['config_target'], strict: false)
> > +    extra_objs +=
target_common_system_arch_libs[rv_base].extract_objects(src.sources())
> > +  endif
> > +  foreach pair : [['arm-softmmu', 'aarch64-softmmu'],
['riscv32-softmmu', 'riscv64-softmmu']]
> > +    t32 = pair[0]
> > +    t64 = pair[1]
> > +    if t32 in target_softmmu
> > +      extra_objs +=
target_softmmu[t32]['lib'].extract_objects(target_info_def)
> > +      base32 = target_softmmu[t32]['target_base_arch']
> > +      if base32 in hw_arch
> > +        hw32 =
hw_arch[base32].apply(target_softmmu[t32]['config_target'], strict: false)
> > +        hw64 =
hw_arch[base32].apply(target_softmmu[t64]['config_target'], strict: false)
> > +        extra_hw = []
> > +        foreach f : hw32.sources()
> > +          if f not in hw64.sources()
> > +            extra_hw += f
> > +          endif
> > +        endforeach
> > +        if extra_hw.length() > 0
> > +          extra_objs +=
target_softmmu[t32]['lib'].extract_objects(extra_hw)
> > +        endif
> > +      endif
> > +    endif
> > +  endforeach
> > +  combo_objects = extra_objs
> > +  combo_objects += a64['lib'].extract_all_objects(recursive: true)
> > +  combo_objects += rv['lib'].extract_objects(rv['arch_srcs'])
> > +  combo_deps = a64['arch_deps'] + rv['arch_deps'] + [sdl,
a64['target_stubs'], rv['target_stubs']]
> > +  if 'arm-softmmu' in target_softmmu
> > +    combo_deps += target_softmmu['arm-softmmu']['arch_deps']
> > +  endif
> > +  if 'riscv32-softmmu' in target_softmmu
> > +    combo_deps += target_softmmu['riscv32-softmmu']['arch_deps']
> > +  endif
> > +  combo_execs = [{
> > +    'name': 'qemu-system',
> > +    'win_subsystem': 'console',
> > +  }]
> > +  if host_os == 'windows' and (sdl.found() or gtk.found())
> > +    combo_execs += [{
> > +      'name': 'qemu-systemw',
> > +      'win_subsystem': 'windows',
> > +    }]
> > +  endif
> > +  combo_exe_suffix = host_os == 'windows' ? '.exe' : ''
> > +  combo_alias_py = 'import os, sys; src, dst = sys.argv[1:3];
os.path.exists(dst) and os.remove(dst); os.symlink(os.path.basename(src),
dst)'
> > +  foreach exe : combo_execs
> > +    emulator = executable(exe['name'], [a64['main_rs'],
files('system/main.c')],
> > +               install: true,
> > +               c_args: a64['c_args'],
> > +               dependencies: combo_deps,
> > +               objects: combo_objects,
> > +               link_depends: [block_syms, qemu_syms],
> > +               link_args: a64['link_args'],
> > +               win_subsystem: exe['win_subsystem'])
> > +    emulators += {exe['name']: emulator}
> > +    traceable += [{
> > +      'exe': exe['name'],
> > +      'probe-prefix': 'qemu.system.multi',
> > +    }]
> > +    foreach t : combo_softmmu
> > +      if t not in target_softmmu
> > +        continue
> > +      endif
> > +      tname = target_softmmu[t]['config_target']['TARGET_NAME']
> > +      if exe['name'] == 'qemu-systemw'
> > +        alias = 'qemu-system-' + tname + 'w'
> > +      else
> > +        alias = 'qemu-system-' + tname
> > +      endif
> > +      alias_tgt = custom_target(alias,
> > +                                input: emulator,
> > +                                output: alias + combo_exe_suffix,
> > +                                command: [python, '-c',
combo_alias_py, '@INPUT@', '@OUTPUT@'],
> > +                                build_by_default: true,
> > +                                install: false)
> > +      emulators += {alias: alias_tgt}
> > +      install_symlink(alias + combo_exe_suffix,
> > +                      pointing_to: exe['name'] + combo_exe_suffix,
> > +                      install_dir: get_option('bindir'))
> > +      traceable += [{
> > +        'exe': alias,
> > +        'probe-prefix': 'qemu.system.' + tname,
> > +      }]
> > +    endforeach
> > +  endforeach
> > +endif
> > +
> >  # Other build targets
> >
> >  if get_option('plugins')
>
> Please find attached a much simpler implementation, which only requires
> a single line update as we add new targets in single-binary.
>
> Regards,
> Pierrick



--
         此致
礼
罗勇刚
Yours
    sincerely,
Yonggang Luo