Re: [PATCH v2 63/93] tcg/tci: Use ffi for calls

[Stefan Weil]

Am 08.02.21 um 10:35 schrieb Paolo Bonzini:

> On 08/02/21 10:20, Peter Maydell wrote:
> > > > > +
> > > > > +if get_option('tcg_interpreter')
> > > > > +  libffi = dependency('libffi', version: '>=3.0',
> > > > > +                      static: enable_static, method: 'pkg-config',
> > > > > +                      required: true)
> > > > > +  specific_ss.add(libffi)
> > > > > +  specific_ss.add(files('tcg/tci.c'))
> > > > > +endif
> > > > Did you need a PKG_CONFIG_LIBDIR set for homebrew?
> > > Is this the "meson doesn't actually add the cflags everywhere it 
> > > should"
> > > bug again ?
>
> No, it shouldn't be the same bug.  In this case the dependency is not 
> indirect dependency, specific_ss is included directly:
>
>   target_specific = specific_ss.apply(config_target, strict: false)
>   arch_srcs += target_specific.sources()
>   arch_deps += target_specific.dependencies()
>
>   lib = static_library('qemu-' + target,
>                  sources: arch_srcs + genh,
>                  dependencies: arch_deps,
>                  objects: objects,
>                  include_directories: target_inc,
>                  c_args: c_args,
>                  build_by_default: false,
>                  name_suffix: 'fa')
>
> It's more likely to be what Stefan pointed out later:
>
> > Meanwhile I noticed an additional detail:
> >
> > There exist two different pkg-config configurations for libffi on 
> > Homebrew:
> >
> > % pkg-config --cflags libffi
> > -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/ffi
> > % export PKG_CONFIG_PATH="/opt/homebrew/opt/libffi/lib/pkgconfig"
> > % pkg-config --cflags libffi
> > -I/opt/homebrew/Cellar/libffi/3.3_2/include
> >
> > By default it points to a system directory which does not exist at all
> > on my Mac, so that will never work.
>
> Paolo


Yes, it looks like setting the right PKG_CONFIG_PATH is sufficient for 
builds with Homebrew on macOS.

Richard, this commit is also the one which breaks qemu-system-i386 on 
sparc64 for me:

sw@gcc102:~/src/gitlab/qemu-project/qemu$ git bisect good
115a01c323e6a01902894ec23ba704bf3dc8215a is the first bad commit
commit 115a01c323e6a01902894ec23ba704bf3dc8215a
Author: Richard Henderson <richard.henderson@linaro.org>
Date:   Sat Jan 30 14:24:25 2021 -0800

    tcg/tci: Use ffi for calls

    This requires adjusting where arguments are stored.
    Place them on the stack at left-aligned positions.
    Adjust the stack frame to be at entirely positive offsets.

    Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

 include/tcg/tcg.h        |   1 +
 tcg/tcg.c                |  72 +++++++++++++++-----------
 tcg/tci.c                | 131 
++++++++++++++++++++++++++---------------------
 tcg/tci/tcg-target.c.inc |  50 +++++++++---------
 tcg/tci/tcg-target.h     |   2 +-
 5 files changed, 143 insertions(+), 113 deletions(-)

Regards,

Stefan