[PATCH] D94882: [MC] Upgrade DWARF version to 5 upon .file 0

Thu Jan 28 00:15:40 PST 2021

jhenderson added a comment.

In D94882#2525883 <https://reviews.llvm.org/D94882#2525883>, @MaskRay wrote:

> The default DWARF version is decided by clang driver. Different toolchains have different defaults. The version option does not require `-g`.
>
>   clang -target x86_64-linux -c a.s '-###' # "-dwarf-version=4"
>   clang -target x86_64-freebsd12 -c a.s '-###' # "-dwarf-version=2"
>
> If we want a diagnostic, we will need additional information whether `-dwarf-version` is implicitly or explicitly specified. GNU as currently does not have a diagnostic.
> I have put reason why I think the diagnostic is not very useful in my initial summary.

Got it now, thanks. I don't have a strong feeling about whether a new option to enable this diagnostic is a good idea or not. If it existed, I'd expect to be something like --warn-for-mismatching-dwarf-version or something to that effect, and is specified automatically if the user explicitly specifies the DWARF version themselvse. I don't think whether GNU as produces a diagnostic or not is really relevant. I think I'd like someone else with more frontend experience to chime in at this point.

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  https://reviews.llvm.org/D94882/new/

https://reviews.llvm.org/D94882