From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: [net-next PATCH V2 5/5] samples/bpf: like LLC also verify and allow redefining CLANG command Date: Wed, 27 Apr 2016 08:45:44 +0200 Message-ID: <20160427084544.0ae46b74@redhat.com> References: <20160426162650.22962.20516.stgit@firesoul> <20160426162732.22962.73140.stgit@firesoul> <20160426173608.GF42777@ast-mbp.thefacebook.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: brouer@redhat.com, netdev@vger.kernel.org, linux-kbuild@vger.kernel.org, bblanco@plumgrid.com, naveen.n.rao@linux.vnet.ibm.com, borkmann@iogearbox.net To: Alexei Starovoitov Return-path: In-Reply-To: <20160426173608.GF42777@ast-mbp.thefacebook.com> Sender: linux-kbuild-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, 26 Apr 2016 10:36:10 -0700 Alexei Starovoitov wrote: > 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. Yes, you read the patch correctly :-) > 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 Good to get confirmation. I was testing with clang 3.5.0, and llc 3.9-git. > Acked-by: Alexei Starovoitov -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer