Em Tue, Sep 27, 2022 at 11:56:34AM -0700, Nathan Chancellor escreveu:
> Hi Arnaldo,
>
> When building a kernel with LLVM and CONFIG_DEBUG_INFO_BTF after commit
> 32ef9e5054ec ("Makefile.debug: re-enable debug info for .S files") in
> the kernel, I see the following spew of warnings, which appear to come
> from pahole:
>
> $ clang --version
> clang version 15.0.0 (Fedora 15.0.0-3.fc38)
> Target: x86_64-redhat-linux-gnu
> Thread model: posix
> InstalledDir: /usr/bin
>
> $ pahole --version
> v1.24
>
> $ make -skj"$(nproc)" ARCH=x86_64 LLVM=1 defconfig
>
> $ scripts/config \
> -d DEBUG_INFO_NONE \
> -e BPF_SYSCALL \
> -e DEBUG_INFO_BTF \
> -e DEBUG_INFO_DWARF5
>
> $ make -skj"$(nproc)" ARCH=x86_64 LLVM=1 olddefconfig all
> ...
> die__process_unit: DW_TAG_label (0xa) @ <0x7b> not handled!
> die__process_unit: tag not supported 0xa (label)!
> die__process_unit: DW_TAG_label (0xa) @ <0x97> not handled!
> die__process_unit: DW_TAG_label (0xa) @ <0xbd> not handled!
> die__process_unit: DW_TAG_label (0xa) @ <0xed> not handled!
> die__process_unit: DW_TAG_label (0xa) @ <0x109> not handled!
> die__process_unit: DW_TAG_label (0xa) @ <0x12a> not handled!
> die__process_unit: DW_TAG_label (0xa) @ <0x146> not handled!
> die__process_unit: DW_TAG_label (0xa) @ <0x16f> not handled!
> ...
>
> Is this a problem with LLVM or pahole? I do not see this when building
> with GCC + GNU as but that could just be a red herring. I assume that
> there could be something missing for processing debug info from
> assembly, perhaps? If there is any further information I can provide or
> anything I can test, I am more than happy to do so.
I'll try to repro, but at first sight it looks like a label in a
DW_TAG_compile_unit/like level, I have to check what that means, but
seems to be just a warning, did the end result made sense?
- Arnaldo
