[LLVMdev] Win32 COFF Support

[Michael Spencer]

On Sun, Sep 26, 2010 at 5:27 PM, Nathan Jeffords
<blunted2night at gmail.com> wrote:
> Hi guys,
> While trying to get dwarf debugging information to work with Win32 COFF
> targets, I came across a couple of issues with the current implementation
> of WinCOFFObjectWriter. Emitting empty section causes debug information to
> invalid, as the presence of certain debug section implies available
> information, and emission of labels as symbols confused gdb about the
> structure of the program.
> The attached patch allows the WinCOFFObjectWriter to drop empty sections,
> and label symbols. It converts relocations targeted at symbols into
> relocations relative to the containing section.
> I have not run the tests in the '/test/MC/COFF', but have run through the
> unit-test framework for my compiler and generated some text executables with
> clang and everything looks to be in order. It may change the output of
> the  '/test/MC/COFF' if the string references are emitted as temporaries.
> -Nathan

The patch looks good, but please follow the LLVM coding conventions.
Also, clang emits warnings on all of the signed-unsigned comparisons,
and the order of initialization for COFFSymbol::MCData.

The test fails, but that's only because it is looking for binary
equivalence, just llc the test and run coff-dump to re update it. I
ran the test-suite with clang -integrated-as with and without your
patch and I got identical results.

So fix the coding conventions, warnings, and update the tests and it's
good. I don't mind doing this if you would prefer.

- Michael Spencer