Re: Support for gcc

["Jose E. Marchesi" <jose.marchesi@oracle.com>]

> Thank you very much. It solved my problem; what bpf-gcc build can now
> be loaded by libbpf.

Glad it helped :)

> BTW, when I tried to use bpf-gcc in godbolt.org, I did not add any
> additional compile options, and it reported an error:
>
> /opt/compiler-explorer/bpf/gcc-trunk-20221225/bpf-unknown-none/lib/gcc/bpf-unknown-none/13.0.0/../../../../bpf-unknown-none/bin/ld:
> -pie not supported
> collect2: error: ld returned 1 exit status
> Compiler returned: 1

Hmm, I just tried and it didn't add -pie to the command line options.  I
think that somehow godbolt.org remembers and re-uses the settings used
by the last user.  At least when it comes to select the cross compiler.
Maybe it is the same with the compilation options...

>
> On Thu, Dec 22, 2022 at 2:26 AM Jose E. Marchesi
> <jose.marchesi@oracle.com> wrote:
>>
>>
>> > So you need a bpf-unknown-none-gcc toolchain.
>> > You can either:
>> >
>> > a) Install a pre-compiled cross available in your distro.
>> >    Debian ships gcc-bpf, for example.  See
>> >    https://gcc.gnu.org/wiki/BPFBackEnd for a list.
>> >
>> > or,
>> >
>> > b) Build crossed versions of binutils and gcc, configuring with
>> >    --target=bpf-unknown-none.
>> >
>> > or,
>> >
>> > c) Use crosstool-ng to build a GCC BPF cross.  We recently added support
>> >    for bpf-unknown-none there.
>>
>> Incidentally, thanks to Marc Poulhiès godbolt.org has now support for
>> nightly builds of GCC BPF.