Re: Target-dependent include path, why?

[Philippe Mathieu-Daudé]

On 9/12/22 16:02, Richard Henderson wrote:
> On 12/9/22 02:51, Markus Armbruster wrote:
> > Richard Henderson <richard.henderson@linaro.org> writes:
> >
> > > On 12/8/22 23:12, Markus Armbruster wrote:
> > > > I stumbled over this:
> > > >       ../include/ui/qemu-pixman.h:12:10: fatal error: pixman.h: No 
> > > > such file or directory
> > > >          12 | #include <pixman.h>
> > > >             |          ^~~~~~~~~~
> > > > Works when included into target-dependent code.
> > > > Running make -V=1 shows we're passing a number of -I only when 
> > > > compiling
> > > > target-dependent code, i.e. together with -DNEED_CPU_H:
> > > >       -I/usr/include/pixman-1 -I/usr/include/capstone 
> > > > -I/usr/include/spice-server -I/usr/include/spice-1
> > > >       -I/usr/include/cacard -I/usr/include/nss3 -I/usr/include/nspr4 
> > > > -I/usr/include/PCSC
> > > >       -isystem../linux-headers -isystemlinux-headers
> > > > Why?
> > >
> > > Because of where [pixman] is added as a dependency in meson.build.
> >
> > Is it added where it is for a reason, or is it accidental?
>
> I don't know for sure, but I doubt it's accidental.
> I'm sure it is where it is based on existing usage.

I hit a similar problem while converting units to be target-independent,
moving them out of specific_ss[] I got:

 In file included from ../monitor/misc.c:38:
 In file included from include/ui/console.h:4:
 include/ui/qemu-pixman.h:12:10: fatal error: 'pixman.h' file not found
 #include <pixman.h>
          ^~~~~~~~~~

The monitor/ dependency is odd because there is no pixman use in the
sources, only pulled by the headers:

  $ git grep pixman monitor/
  monitor/meson.build:9:specific_ss.add(when: 'CONFIG_SOFTMMU', 
if_true: [files('misc.c'), spice, pixman])

We require pixman for system emulation. The dependency is added in 
ui/meson.build:

  softmmu_ss.add(pixman)
  specific_ss.add(when: ['CONFIG_SOFTMMU'], if_true: pixman)   # for 
the include path

Due to the second line, I was expecting all files in specific_ss[] to 
have pixman path in their CPPFLAGS. The monitor/meson.build has:

  specific_ss.add(when: 'CONFIG_SOFTMMU', if_true: [files('misc.c'), 
spice])

Paolo, is it due to the [] that monitor/misc.c doesn't get the pixman
pkg-config flags?