Re: [meson.bbclass] bindgen_clang_arguments lacks C++ include paths, breaks C++ bindgen (mesa rusticl)

[Paul Barker <paul@pbarker.dev>]

On Mon, 2026-09-21 at 13:11 +0400, Royyan Zahir wrote:
> Hi Paul,
> 
> Thanks for looking. Versions first, then the trigger, then what I have not yet
> established.
> 
> Layers, all pinned:
> 
>   openembedded-core  wrynose  f7397af248e1e338929d70a910b0fbc2341528ec
>   bitbake            2.18     0ad6c1c34a5e07a5f8dd66ab248c1e7b37b69fa9
>   meta-openembedded  wrynose  14282a02be9c74a1276a7cda7d6c89e054699a11
>   meta-qcom          wrynose  ef0004df267743cc89d6a09bc724bc99ff541c01
> 
> Target is aarch64, mesa 26.0.5, LLVM 22.1.3, bindgen from bindgen-cli-native.
> 
> The trigger is only this:
> 
>   DISTRO_FEATURES:append = " opencl"
> 
> which selects mesa's PACKAGECONFIG[opencl], so -Dgallium-rusticl=true, and the
> rusticl frontend runs bindgen over a C++ header. The failing command ends with
> -x c++ -std=c++17 on rusticl_llvm_bindings.hpp, and clang cannot find cassert
> from llvm/ADT/DenseMapInfo.h.
> 
> What I cannot give you is a runnable command line: our DISTRO and MACHINE are
> in a layer I cannot share, and I have not yet reduced this to stock poky. I
> tried to on the shared builder this morning and it refused before parsing with
> 
>   ERROR: User namespaces are not usable by BitBake, possibly due to AppArmor.
> 
> so that attempt proved nothing. Our own builds go through a wrapper that
> handles it.
> 
> My reading is that nothing platform-specific is involved: bindgen_args() in
> meson.bbclass passes HOST_CC_ARCH, TOOLCHAIN_OPTIONS and --target, and none of
> those carry the libstdc++ include directories that clang needs when it
> cross-compiles against a GCC sysroot. Any meson recipe running bindgen over a
> C++ header should hit it. If that reasoning is wrong I would rather know than
> have you chase our stack.
> 
> Happy to build a stock qemuarm64 case with opencl in DISTRO_FEATURES on a
> machine without the namespace restriction and report back, or to test a patch
> on aarch64, whichever is more useful.

Yes, I'd like you to confirm that the error happens on stock
poky/qemuarm64 with just the DISTRO_FEATURES change to enable opencl.

Also, please quote the email you're replying to so it's easier to follow
the conversation.

Best regards,

-- 
Paul Barker