[PATCH] D50294: [Driver] Use -gdwarf-3 by default for FreeBSD

Ed Maste via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Wed Apr 24 13:09:09 PDT 2019

emaste added a subscriber: arichardson.
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Herald added a project: clang.

In D50294#1246980 <https://reviews.llvm.org/D50294#1246980>, @MaskRay wrote:

> In D50294#1245454 <https://reviews.llvm.org/D50294#1245454>, @emaste wrote:
> > I'm using this change: https://github.com/emaste/freebsd/commit/1c3deab6d518feb1a7e88de5b342a139e4022a21
> >
> > In FreeBSD 12 and later we use Clang, lld, and ELF Tool Chain. (We still have gas and objdump from the outdated binutils 2.17.50.)
> Will you upstream this commit (I can abandon this one)? I created this revision because I was learning clangDriver... I had a vague and probably incorrect impression that some folks said kgdb or dtrace or whatever might not support DWARF 3 or 4.

Hmm, somehow I forgot about this until being reminded by @arichardson just now. I will upstream it.

The primary motivation for staying with DWARF2 was indeed kgdb, based on gdb 6.1.1, and dtrace (specifically dtrace's build tool ctfconvert) also did not support DWARF >2. However, these issues have all been addressed:

1. We're deprecating gdb 6.1.1-based kgdb, using a contemporary gdb port.
2. In any case the kernel is still building with explicit -gdwarf2 today so it doesn't matter anyhow, there's no need for the toolchain default to be set based on the kernel's needs.
3. DTrace tooling limitations arose as a side effect of our (well, ELF Tool Chain's) libdwarf but it has been updated to handle DWARF4 some time ago.

Perhaps I should just upload a new diff to this review?

  rC Clang



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