Re: [PATCH] Kbuild: implement support for DWARF5

Arvind Sankar
2020-11-04T00:00:21Z

On Wed, Oct 21, 2020 at 06:21:06PM -0700, Nick Desaulniers wrote:
> DWARF5 is the latest standard of the DWARF debug info format.
>
> Feature detection of DWARF5 is onerous, especially given that we've
> removed $(AS), so we must query $(CC) for DWARF5 assembler directive
> support. Further -gdwarf-X where X is an unsupported value doesn't
> produce an error in $(CC). GNU `as` only recently gained support for
> specifying -gdwarf-5.

Do you have more details here? On godbolt.org, gcc does report an error
for unsupported dwarf versions.

https://godbolt.org/z/G35798

gcc does not seem to pass the -gdwarf-* options to the assembler when
compiling C source. For assembler, gcc will pass an appropriate option
depending on the version of binutils it was configured with: if the
assembler doesn't support dwarf-5 it can call it with --gdwarf2 for eg.

If the user is using a properly configured toolchain it doesn't look
like it should be an issue to just use cc-option?