On 07/01/2019 08:40 PM, Ilya Leoshkevich wrote: > Am 01.07.2019 um 17:31 schrieb Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>: >> Do we still need clang | llc pipeline with new clang? Could the same >> be achieved with single clang invocation? That would solve the problem >> of not detecting pipeline failures. > > I’ve experimented with this a little, and found that new clang: > > - Does not understand -march, but -target is sufficient. > - Understands -mcpu. > - Understands -Xclang -target-feature -Xclang +foo as a replacement for > -mattr=foo. > > However, there are two issues with that: > > - Don’t older clangs need to be supported? For example, right now alu32 > progs are built conditionally. We usually require latest clang to be able to test most recent features like BTF such that it helps to catch potential bugs in either of the projects before release. > - It does not seem to be possible to build test_xdp.o without -target > bpf. For everything non-tracing, it does not make sense to invoke clang w/o the -target bpf flag, see also Documentation/bpf/bpf_devel_QA.rst +573 for more explanation, so this needs to be present for building test_xdp.o. Thanks, Daniel
