From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexei Starovoitov Subject: Re: [net-next PATCH V2 5/5] samples/bpf: like LLC also verify and allow redefining CLANG command Date: Tue, 26 Apr 2016 10:36:10 -0700 Message-ID: <20160426173608.GF42777@ast-mbp.thefacebook.com> References: <20160426162650.22962.20516.stgit@firesoul> <20160426162732.22962.73140.stgit@firesoul> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, linux-kbuild@vger.kernel.org, bblanco@plumgrid.com, naveen.n.rao@linux.vnet.ibm.com, borkmann@iogearbox.net To: Jesper Dangaard Brouer Return-path: Received: from mail-pf0-f172.google.com ([209.85.192.172]:35353 "EHLO mail-pf0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752463AbcDZRgP (ORCPT ); Tue, 26 Apr 2016 13:36:15 -0400 Content-Disposition: inline In-Reply-To: <20160426162732.22962.73140.stgit@firesoul> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Apr 26, 2016 at 06:27:32PM +0200, Jesper Dangaard Brouer wrote: > Users are likely to manually compile both LLVM 'llc' and 'clang' > tools. Thus, also allow redefining CLANG and verify command exist. > > Makefile implementation wise, the target that verify the command have > been generalized. > > Signed-off-by: Jesper Dangaard Brouer > --- > samples/bpf/Makefile | 23 +++++++++++++---------- > samples/bpf/README.rst | 6 +++--- > 2 files changed, 16 insertions(+), 13 deletions(-) > > diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile > index dd63521832d8..c02ea9d2a248 100644 > --- a/samples/bpf/Makefile > +++ b/samples/bpf/Makefile > @@ -81,9 +81,10 @@ HOSTLOADLIBES_spintest += -lelf > HOSTLOADLIBES_map_perf_test += -lelf -lrt > HOSTLOADLIBES_test_overhead += -lelf -lrt > > -# Allows pointing LLC to a LLVM backend with bpf support, redefine on cmdline: > -# make samples/bpf/ LLC=~/git/llvm/build/bin/llc > +# Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline: > +# make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang > LLC ?= llc > +CLANG ?= clang > > # Trick to allow make to be run from this directory > all: > @@ -94,15 +95,17 @@ clean: > @rm -f *~ > > # Verify LLVM compiler is available and bpf target is supported > -.PHONY: verify_cmd_llc verify_target_bpf > +.PHONY: verify_cmd_llc verify_target_bpf $(CLANG) $(LLC) > > -verify_cmd_llc: > - @if ! (which "${LLC}" > /dev/null 2>&1); then \ > - echo "*** ERROR: Cannot find LLVM tool 'llc' (${LLC})" ;\ > - exit 1; \ > - else true; fi > +verify_cmds: $(CLANG) $(LLC) > + @for TOOL in $^ ; do \ > + if ! (which "$${TOOL}" > /dev/null 2>&1); then \ > + echo "*** ERROR: Cannot find LLVM tool $${TOOL}" ;\ > + exit 1; \ > + else true; fi; \ > + done > > -verify_target_bpf: verify_cmd_llc > +verify_target_bpf: verify_cmds > @if ! (${LLC} -march=bpf -mattr=help > /dev/null 2>&1); then \ > echo "*** ERROR: LLVM (${LLC}) does not support 'bpf' target" ;\ > echo " NOTICE: LLVM version >= 3.7.1 required" ;\ If I read the patch correctly, it only checks that any version of clang is available and llc supports -march=bpf. That's correct. There is no need to build the latest clang most of the time. clang 3.4 and 3.5 are fine to compile samples/bpf/ since llvm ir is mostly compatible with llc from 3.7 or 3.8 Acked-by: Alexei Starovoitov