[llvm-commits] [PATCH] Fix emission of debug data for global variables

[James Molloy]

Hi Devang,

Thanks. As the testcase needs to compile down to assembly (to test the DWARF
output), is the target triple really unnecessary?

Cheers,

James

-----Original Message-----
From: Devang Patel [mailto:dpatel at apple.com] 
Sent: 26 September 2011 18:19
To: James Molloy
Cc: Commit Messages and Patches for LLVM
Subject: Re: [llvm-commits] [PATCH] Fix emission of debug data for global
variables

James,

Your patch looks good. Please apply (remove target datalayout and target
triple from the test case because it is unnecessary).
Thanks!
-
Devang
On Sep 26, 2011, at 9:03 AM, James Molloy wrote:

> Hi,
> 
> With the new debug information changes, global variables aren't emitted
properly to DWARF. The DW_AT_decl_file field is incorrect.
> 
> This stems from DwarfCompileUnit.cpp:138:
> 
>  unsigned FileID = DD->GetOrCreateSourceID(G.getContext().getFilename(),
>                                            G.getContext().getDirectory());
> 
> G.getContext() returns a NULL metadatum for the new metadata format (it
used to return the CompileUnit). This causes a new SourceID to be generated
for the "null" file, and the global is assigned this incorrect SourceID.
> 
> Attached is a testcase and proposed patch. It inlines getFilename() and
getDirectory() into DIGlobalVariable, returning the original
getContext().getFilename() for old versions of the debug info and
getFieldAs<DIFile>(6).getFilename() for new versions.
> 
> I've implemented it this way so that the old code path is identical to
before. I'm not sure if this is the most perfect fix - as
getFieldAs<DIFile>(6) is valid (seemingly) for all debug info versions,
perhaps the best idea would be to remove the conditionalization and always
return getFieldAs<DIFile>(6).getFilename/getDirectory() ?
> 
> 
> Cheers,
> 
> James
> 
> 
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