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
