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.
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 <ast@xxxxxxxxxx>
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