[llvm-dev] BPF: How can I enable BPF support in my LLVM toolchain?

[Sedat Dilek via llvm-dev]

On Mon, Jan 11, 2021 at 4:35 PM Tom Stellard <tstellar at redhat.com> wrote:
>
> On 1/11/21 5:35 AM, Sedat Dilek via llvm-dev wrote:
> > Hi,
> >
> > when building a Linux-kernel with CONFIG_DEBUG_INFO_BTF=y my build breaks.
> >
>
> I commented on the GitHub issue about the root cause of this.
>
> > This is because my selfmade LLVM toolchain v11.0.1 has no BPF support:
> >
> > $ llc --version
> > LLVM (http://llvm.org/):
> >   LLVM version 11.0.1
> >   Optimized build.
> >   Default target: x86_64-unknown-linux-gnu
> >   Host CPU: sandybridge
> >
> >   Registered Targets:
> >     x86    - 32-bit X86: Pentium-Pro and above
> >     x86-64 - 64-bit X86: EM64T and AMD64
> >
> > What system or binary requirements do I need and which CMAKE option(s)
> > need(s) to be set?
>
> The LLVM_TARGETS_TO_BUILD CMake option controls which targets to build.
>

tc-build folks fixed that up.
See commit "build-llvm.py: Enable BPF backend by default".

Is there a BPF test-suite - like for clang and lld?

I have build pahole from Git - now building a new Linux kernel.

$ cd /path/to/pahole/git
$ git describe
v1.19-7-gb688e3597060

Will report later.

Regards,
- Sedat -

[1] https://github.com/ClangBuiltLinux/tc-build/commit/e796c046428a971404eec008c841f9dd7c1621e8

> -Tom
>
> > I hope this is not hardware-dependent (here: Intel SandyBridge).
> >
> > Thanks in advance.
> >
> > Regards,
> > - Sedat -
> >
> > [1] https://github.com/ClangBuiltLinux/tc-build/issues/129
> > _______________________________________________
> > LLVM Developers mailing list
> > llvm-dev at lists.llvm.org
> > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >
>