[LLVMdev] [lld] Relocation sections format: .rela / .rel

Shankar Easwaram shankarke at gmail.com
Sun Jan 19 13:36:22 PST 2014

I think the linking context should decide whether to use rel (or) rela. This is also needed if --emit-relocations option is chosen (or) -r option is used. 

Thoughts ?

Sent from my iPhone

> On Jan 19, 2014, at 15:01, Simon Atanasyan <simon at atanasyan.com> wrote:
> Hi,
> Now lld writes relocations to the ".rela" sections only. Mips requires
> to use the "rel" format. So we need to be able to select format and
> names of relocation section, names of symbols like __rela_iplt_* /
> __rel_iplt_*, dynamic table tag DT_RELA / DT_REL.
> My current idea:
> - Add two virtual functions
> DefaultLayout::createDynamicRelocationTable() and
> DefaultLayout::getPLTRelocationTable(). Call these functions when we
> need to create relocation tables. By default these function create
> .rela.* sections.
> - Override createDynamicRelocationTable() and getPLTRelocationTable()
> in the MipsTargetLayout to create .rel.* sections.
> - Add support for writing Elf_Rel entries to the RelocationTable
> class. Maybe it's better to inherit form RelocationTable two separate
> classes deal with lf_Rela / Elf_Rel entries.
> - It's unclear to me how to select names of symbols like __rela_iplt_*
> / __rel_iplt_* and dynamic table tag DT_RELA / DT_REL.
> Is it an appropriate solution? Any objections or suggestions?
> Thanks.
> -- 
> Simon Atanasyan

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