[LLVMdev] Win32 COFF Support

[Michael Spencer]

On Sun, Sep 26, 2010 at 6:47 PM, Nathan Jeffords
<blunted2night at gmail.com> wrote:
> On Sun, Sep 26, 2010 at 3:28 PM, Michael Spencer <bigcheesegs at gmail.com>
> wrote:
>>
>> 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
>
> If you don't mind then please make the appropriate changes. Thanks.
> -Nathan

Committed in r114823.

- Michael Spencer