On Tue, 26 Apr 2016 10:36:10 -0700
Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> 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 <brouer@xxxxxxxxxx>
> > ---
> > 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 <ast@xxxxxxxxxx>
--
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
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