[PATCH] D26051: Import/update constants from the DWARF 5 public review draft document.

[David Blaikie via llvm-commits]

On Thu, Oct 27, 2016 at 5:13 PM Adrian Prantl <aprantl at apple.com> wrote:

> aprantl created this revision.
> aprantl added reviewers: echristo, dblaikie, probinson.
> aprantl added subscribers: clayborg, llvm-commits.
> Herald added a subscriber: mehdi_amini.
>
> I noticed two incompatible changes:
>
> 1. DW_AT_dwo_id was removed because the dwo_id was moved into the CU
> header. Note that the attribute
>

Well, that's a nice change... I should read the spec in more detail. (it
would avoid the DWP tool from having to parse any DWARF, I think - though
it's still nice to parse some to find the dwo_name for better diagnostics,
at least we can wait until we've identified a problem before doing that
anyway)


> value was reserved, so LLVM can continue to emit it without causing
> ambiguity for now.
>
> 1. The one change that could cause a problem here is that
> DW_AT_ranges_base has been replaced by DW_AT_rnglist_base.
>

That's a weird one - how's a DWARF consumer meant to identify whether
they're dealing with new or old (whether they should look in debug_ranges
or debug_rnglists)? Just based on the version in the header? (is there
prior art for that sort of technique?)

I suppose in theory our dumper could be smart enough to print the right
attribute string depending on version - though that seems annoying...

- David


>
> David/Eric: Would merely renaming the constant break any existing DWARF
> (4) tooling?
>
>
> https://reviews.llvm.org/D26051
>
> Files:
>   include/llvm/Support/Dwarf.def
>   include/llvm/Support/Dwarf.h
>   lib/DebugInfo/DWARF/DWARFDebugInfoEntry.cpp
>   lib/DebugInfo/DWARF/DWARFUnit.cpp
>   lib/Support/Dwarf.cpp
>
>
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