[net-next PATCH 2/4] samples/bpf: Makefile verify LLVM compiler avail and bpf target is supported

Jesper Dangaard Brouer
2016-04-26T11:09:25Z

Make compiling samples/bpf more user friendly, by detecting if LLVM
compiler tool 'llc' is available, and also detect if the 'bpf' target
is available in this version of LLVM.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
---
samples/bpf/Makefile | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 5bae9536f100..7ac66f5bbbf5 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -85,6 +85,24 @@ HOSTLOADLIBES_test_overhead += -lelf -lrt
# make samples/bpf/ LLC=~/git/llvm/build/bin/llc
LLC ?= llc

+# Verify LLVM compiler is available and bpf target is supported
+.PHONY: verify_cmd_llc verify_target_bpf
+
+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_target_bpf: verify_cmd_llc
+ @if ! (${LLC} -march=bpf -mattr=help > /dev/null 2>&1); then \
+ echo "*** ERROR: LLVM (${LLC}) does not support 'bpf' target" ;\
+ echo " NOTICE: LLVM version >= 3.7.0 required" ;\
+ exit 2; \
+ else true; fi
+
+$(src)/*.c: verify_target_bpf
+
# asm/sysreg.h - inline assembly used by it is incompatible with llvm.
# But, there is no easy way to fix it, so just exclude it since it is
# useless for BPF samples.