[LLVMdev] PIC documentation ?

Aaron Gray aaronngray.lists at googlemail.com
Tue Jun 16 13:40:31 PDT 2009


>> Can I ask what platform ABI's are documented other than Itanium ?
> I'd bet all platform ABI are more or less documented.


Maybe we should collect references and do some LLVM PIC documentation and 
put it on LLVM website ?

>> I need to get to understand PIC on x86, x86_64 and PowerPC for the COFF 
>> and MachO backends.
> ABI is normally induced by platform, not by architecture or object
> file format (however they can influence on it).


> 1. Windows is PIC by design. Google for PE file format and for
> 'relocs' section. This corresponds to LLVM's DynamicNoPIC

Okay I have this documentation.

> 2. ABI docs for Darwin (x86, x86_64, ppc, ppc64) you might find
> somewhere @apple.com. There you can have all 3 types of PIC code:
> static (no pic at all), DynamicNoPIC and full PIC.

Okay. We need documentation, what is the difference between DynamicNoPIC and 
full PIC ?

> 3. COFF is usually not used on PPC at all (maybe on some old AIX'es?).


> Since you did not mention ELF, I assume you already found ABI docs
> for it (for all platforms).

I am not working on the ELF backend, but could not understand the PIC code 
in the ELF documentation.



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