On 03/31/2016 07:46 PM, Alexei Starovoitov wrote:

On 3/31/16 4:25 AM, Naveen N. Rao wrote:

quoted

While at it, fix some typos in the comment.

Cc: Alexei Starovoitov <redacted>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ananth N Mavinakayanahalli <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <redacted>
---
  samples/bpf/Makefile | 11 ++++-------
  1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 502c9fc..88bc5a0 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile

@@ -76,16 +76,13 @@ HOSTLOADLIBES_offwaketime += -lelf
  HOSTLOADLIBES_spintest += -lelf
  HOSTLOADLIBES_map_perf_test += -lelf -lrt

-# point this to your LLVM backend with bpf support
-LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc
-
-# asm/sysreg.h inline assmbly used by it is incompatible with llvm.
-# But, ehere is not easy way to fix it, so just exclude it since it is
+# 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.
  $(obj)/%.o: $(src)/%.c
      clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \
          -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \
-        -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@
+        -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=obj -o $@
      clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \
          -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \
-        -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=asm -o $@.s
+        -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=asm -o $@.s

that was a workaround when clang/llvm didn't have bpf support.
Now clang 3.7 and 3.8 have bpf built-in, so make sense to remove
manual calls to llc completely.
Just use 'clang -target bpf -O2 -D... -c $< -o $@'

+1, the clang part in that Makefile should also more correctly be called
with '-target bpf' as it turns out (despite llc with '-march=bpf' ...).
Better to use clang directly as suggested by Alexei.