[PATCH] D69822: [clang] Add new -fdebug-default-version flag.

[David Blaikie via Phabricator via cfe-commits]

dblaikie added a comment.

In D69822#1733262 <https://reviews.llvm.org/D69822#1733262>, @probinson wrote:

> In D69822#1733243 <https://reviews.llvm.org/D69822#1733243>, @dblaikie wrote:
>
> > In D69822#1733226 <https://reviews.llvm.org/D69822#1733226>, @probinson wrote:
> >
> > > > Want to decouple setting the DWARF version from enabling/disabling generation of debug info.
> > >
> > > Um, why?
> >
> >
> > If you've got a big build system with various users opting in/out of DWARF and you want to migrate to DWARFv5, say, but you can't add "-gdwarf-5" to your build system, because that'd turn on debug info in cases that don't need it - but it's easier to change the default than to modify all cases that enable dwarf across the codebase.
> >
> > Open to discussion about whether this is a good/bad idea - but it'd be useful for Google at least & seemed low-cost enough to go this route.
>
>
> Because you want the default to be based on your corporate environment rather than the target platform.


Sure - if we know our users have access to a modern debugger, but we don't own a whole platform. You could imagine someone shipping clang+debugger in a 3rd party/non-platform IDE might want something like this too/similar to the Google situation. We can't dictate what's suitable for all of Linux, but for the subset of users that are using a specific toolchain/situation, we can.

> The maze of twisty -g passages gets a new secret door.  Oh well.

If you find this to be a significant complication, I'd really like to discuss it further - I know there are some twisty things (one of the worst I created when it comes to -fsplit-dwarf-inlining, -gsplit-dwarf, -gmlt combinations) - but this seems pretty simple/tidy/orthogonal to me.


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https://reviews.llvm.org/D69822