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

[James Molloy]

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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