On 2016/03/31 08:19PM, Daniel Borkmann wrote: > On 03/31/2016 07:46 PM, Alexei Starovoitov wrote: > >On 3/31/16 4:25 AM, Naveen N. Rao wrote: > >> 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.
I'm likely missing something obvious, but I cannot get this to work. With this diff: $(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 $@ - 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 -target bpf -c $< -o $@ I see far too many errors thrown starting with: clang -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.8.2/include -I./arch/x86/include -Iarch/x86/include/generated/uapi -Iarch/x86/include/generated -Iinclude -I./arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I./include/uapi -Iinclude/generated/uapi -include ./include/linux/kconfig.h \ -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ -O2 -target bpf -c samples/bpf/map_perf_test_kern.c -o samples/bpf/map_perf_test_kern.o In file included from samples/bpf/map_perf_test_kern.c:7: In file included from include/linux/skbuff.h:17: In file included from include/linux/kernel.h:10: In file included from include/linux/bitops.h:36: In file included from ./arch/x86/include/asm/bitops.h:500: ./arch/x86/include/asm/arch_hweight.h:31:10: error: invalid output constraint '=a' in asm : "="REG_OUT (res) ^ ./arch/x86/include/asm/arch_hweight.h:59:10: error: invalid output constraint '=a' in asm : "="REG_OUT (res) What am I missing? - Naveen