Re: [PATCH 2/4] kconfig: express dependency of individual boards on libfdt

[Paolo Bonzini]

On Tue, May 7, 2024 at 9:48 AM Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
>
> On 7/5/24 09:19, Paolo Bonzini wrote:
> > Now that boards are enabled by default and the "CONFIG_FOO=y"
> > entries are gone from configs/devices/, there cannot be any more
> > a conflicts between the default contents of configs/devices/
> > and a failed "depends on" clause.
> >
> > With this change, each individual board or target can express
> > whether it needs FDT.  It can also include it in the
> > build via "select DEVICE_TREE", instead of having each hw/*/meson.build
> > file do it by hand, and this will bring in more components
> > such as CONFIG_GUEST_LOADER.
> >
> > This allows building non-microvm x86 emulators without having
> > libfdt available.
> >
> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> > ---
> >   meson.build               |  1 +
> >   Kconfig.host              |  3 +++
> >   hw/arm/Kconfig            |  5 +++++
> >   hw/arm/meson.build        |  2 +-
> >   hw/core/Kconfig           |  9 ++++++++-
> >   hw/core/meson.build       |  2 +-
> >   hw/i386/Kconfig           |  3 ++-
> >   hw/loongarch/Kconfig      |  3 ++-
> >   hw/loongarch/meson.build  |  2 +-
> >   hw/mips/Kconfig           |  1 +
> >   hw/mips/meson.build       |  2 +-
> >   hw/openrisc/Kconfig       |  2 ++
> >   hw/openrisc/meson.build   |  4 ++--
> >   hw/ppc/Kconfig            | 15 ++++++++-------
> >   hw/ppc/meson.build        |  4 +---
> >   hw/riscv/Kconfig          |  4 ++++
> >   hw/riscv/meson.build      |  2 +-
> >   hw/rx/Kconfig             |  3 ++-
> >   hw/xtensa/Kconfig         |  1 +
> >   system/meson.build        |  2 +-
> >   target/arm/Kconfig        |  2 ++
> >   target/microblaze/Kconfig |  1 +
> >   target/openrisc/Kconfig   |  1 +
> >   target/riscv/Kconfig      |  2 ++
> >   24 files changed, 54 insertions(+), 22 deletions(-)
>
>
> > diff --git a/hw/arm/meson.build b/hw/arm/meson.build
> > index 6808135c1f7..aefde0c69a3 100644
> > --- a/hw/arm/meson.build
> > +++ b/hw/arm/meson.build
> > @@ -1,5 +1,5 @@
> >   arm_ss = ss.source_set()
> > -arm_ss.add(files('boot.c'), fdt)
> > +arm_ss.add(files('boot.c'))
>
> Don't we need to add fdt includes path to CPPFLAGS?

Good catch! I thought it'd be done automatically for all dependencies
included in common_ss (system_ss is included in common_ss and lists
fdt as a dependency), but actually it needs a small tweak:

diff --git a/meson.build b/meson.build
index 24502f4ff6a..342df23269d 100644
--- a/meson.build
+++ b/meson.build
@@ -3898,7 +3898,7 @@ foreach target : target_dirs

   target_common = common_ss.apply(config_target, strict: false)
   objects = common_all.extract_objects(target_common.sources())
-  deps = target_common.dependencies()
+  arch_deps += target_common.dependencies()

   target_specific = specific_ss.apply(config_target, strict: false)
   arch_srcs += target_specific.sources()
@@ -3954,7 +3954,7 @@ foreach target : target_dirs
     emulator = executable(exe_name, exe['sources'],
                install: true,
                c_args: c_args,
-               dependencies: arch_deps + deps + exe['dependencies'],
+               dependencies: arch_deps + exe['dependencies'],
                objects: lib.extract_all_objects(recursive: true),
                link_depends: [block_syms, qemu_syms],
                link_args: link_args,

I'll include it in a v2 once I test it more fully.

Paolo