Re: clang --target=bpf missing on f23 was: Re: [PATCH 1/2] perf test: Add libbpf relocation checker

From: Alexei Starovoitov
Date: Fri Jan 22 2016 - 12:42:36 EST


On Fri, Jan 22, 2016 at 12:35:42PM -0500, Adam Jackson wrote:
> On Fri, 2016-01-22 at 14:22 -0300, Arnaldo Carvalho de Melo wrote:
>
> > the 'bpf' target for clang is being used together with perf to
> > build scriptlets into object code that then gets uploaded to the kernel
> > via sys_bpf(), was the decision not to include 'bpf' just an accident?
>
> I wouldn't call it a "decision", that would imply intent. The main
> reason I explicitly list targets for llvm is to limit the CPU backends
> to arches Fedora actually runs on (which itself is because I really
> only care about llvmpipe, and am only touching llvm because it's in my
> way). Had no idea there was a bpf backend, so never thought to enable
> it.
>
> llvm-3.7.0-4.fc2{3,4} are building now with the bpf backend enabled,
> I'll create an update for F23 when it's built.

thanks.
if you want to reduce the size of binaries, you can probably disable
nvptx/amdgcn/r600, since I doubt fedora ships with appropriate sdks
that can take advantage of that.