[LLVMdev] Comment "FIXME" in X86MachObjectWriter::RecordX86Relocation

[Jim Grosbach]

Hi Verena,

Windows + MachO is likely to run into lots of problems once you start passing in non-trivial code. The relocation model is very tied to Darwin.

I believe some folks doing JIT on Windows have had some success w/ ELF. Hopefully someone more familiar with the specifics of that will chime in.

-Jim

On Jun 29, 2012, at 8:58 AM, Verena Beckham <verena at codeplay.com> wrote:

> Hi,
> 
> In X86MachObjectWriter::RecordX86Relocation I found the comment
> 
> 
>   if (Target.isAbsolute()) { // constant
>     // SymbolNum of 0 indicates the absolute section.
>     //
>     // FIXME: Currently, these are never generated (see code below). I 
> cannot
>     // find a case where they are actually emitted.
>     Type = macho::RIT_Vanilla;
>   }
> 
> Is the FIXME still true? I've got some code that hits this, and it seems 
> any code doing a function call to an absolute address (as described in 
> this bug for ELF: http://llvm.org/bugs/show_bug.cgi?id=8656) would hit 
> this. (Although I haven't tried it)
> 
> I'm using Windows 32bit x86 Mach-O, with MCJIT.
> 
> Trying to find a bug within my program and wondered whether the code is 
> just not supported by LLVM. Let me know if you need a testcase.
> 
> Thanks!
> 
> 
> -- 
> Verena Beckham
> 
> Vice President Engineering
> 
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