Question

如果我从linux内核编译samples / bpf /并将优化更改为-O0，我会收到以下错误。虽然使用-O2（Makefile中的默认值）可以正常工作。

任何人都可以解释一下这里的错误。

$ make samples/bpf/

[...]

clang  -nostdinc -isystem /usr/lib/gcc/x86_64-linux-gnu/4.9/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__ -Wno-unused-value -Wno-pointer-sign \
    -O0 -emit-llvm -c samples/bpf/tracex1_kern.c -o -| /home/ravi/bin/llc -march=bpf -filetype=obj -o samples/bpf/tracex1_kern.o
LLVM ERROR: Cannot select: t12: ch,glue = BPFISD::CALL t11, t6, Register:i64 %R1, t11:1
  t6: i64,ch = load<LD8[getelementptr inbounds (%struct.smp_ops, %struct.smp_ops* @smp_ops, i32 0, i32 3)]> t0, t3, undef:i64
    t3: i64 = add t16, Constant:i64<24>
      t16: i64 = BPFISD::Wrapper TargetGlobalAddress:i64<%struct.smp_ops* @smp_ops> 0
        t15: i64 = TargetGlobalAddress<%struct.smp_ops* @smp_ops> 0
      t2: i64 = Constant<24>
    t5: i64 = undef
  t10: i64 = Register %R1
  t11: ch,glue = CopyToReg t9, Register:i64 %R1, Constant:i64<0>
    t10: i64 = Register %R1
    t4: i64 = Constant<0>
In function: smp_send_stop
samples/bpf/Makefile:66: recipe for target 'samples/bpf/tracex1_kern.o' failed
make[1]: *** [samples/bpf/tracex1_kern.o] Error 1
Makefile:1544: recipe for target 'samples/bpf/' failed
make: *** [samples/bpf/] Error 2

Answer 1

这是BPF端口中的一个错误。请在llvm.org上提交有关复制说明的错误。谢谢！

使用-O0编译linux内核（4.4）bpf样本会导致错误

1 个答案: