[PATCH] D30206: [DWARF5] Emit new unit header

[David Blaikie via llvm-commits]

On Tue, Feb 21, 2017 at 10:59 AM Robinson, Paul <paul.robinson at sony.com>
wrote:

> aprantl wrote:
> > This should probably be tested by a llvm-dwarfdump test?
> Are there llvm-dwarfdump tests?
>
>
>
> There are some - using checked in binary/object files.
>
>
>
>   I couldn't find any.  There is a test/tools/llvm-dwarfdump directory
> (with AArch64 and ARM subdirectories) but not actual files.
>
>
>
> There are some in test/DebugInfo/dwarfdump* I think.
>
>
>
> okay….  I can see an argument for having them there, as it's really the
> DebugInfo library and llvm-dwarfdump is basically just a frontend for the
> library.  If that's where people want them, okay.
>
>
>
> Checked-in binaries seems like overkill in some cases.  For .debug_info
> stuff I'd be more inclined to start with assembler source, run llvm-mc, and
> dump the result.  Can't do that for things the assembler actually produces,
> like line tables, but for a lot of things it would be easier to deal with.
>
>
>
> This code was needed because there are a couple of debug-info tests that
> specify version 5 in the IR, and then use llvm-dwarfdump in their RUN
> lines.  Having done this change, I had to fix the unit-test DWARF generator
> because the unit tests were failing.
>
>
>
> What was it that caused breakage in the DwarfGenerator once llvm-dwarfdump
> had v5 support?
>
>
>
> Some of the unit tests (I think these are ones that Greg Clayton added
> relatively recently) are designed to run on both v4 and v5.
>

Oh, right, now I remember those going in when someone wanted a DWARF5
attribute. Thanks for the reminder!


> Once the DebugInfo APIs started treating the v5 header differently, the
> unit tests broke for v5 because the generator emitted a v4-format header
> with version=5.  This meant the generator put the abbrev table pointer at
> offset 6 in the header, but DebugInfo was looking for it at offset 8.  With
> a bogus abbrev table pointer, the DIEs didn't decode as expected, and the
> tests failed. So I fixed the generator to emit the correct v5 format.
>
>
>
> --paulr
>
>
>
>
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