llvm dev - Nov 2015 - [lld] Special R_MIPS_HI16 / R_MIPS_LO16 calculation for _gp_disp symbol

Separated from the "[lld] R_MIPS_HI16 / R_MIPS_LO16 calculation"
thread.

On Sat, Nov 21, 2015 at 9:28 AM, Rui Ueyama <ruiu at google.com>
wrote:
> On Fri, Nov 20, 2015 at 10:13 PM, Simon Atanasyan <simon at
atanasyan.com>
> wrote:
>> R_MIPS_HI16 and R_MIPS_LO16 relocations perform a special calculation
>> if a target symbol's name is `_gp_disp` [2]. AFAIK now in the
target
>> `relocateOne` method there is no chance to get the traget symbol name.
>> Is it okay to pass the target symbol index and provide
>> `MipsTargetInfo` access to the symbol table of the processing input
>> file?
>
>
> One way is to add a SymbolBody* field to Out<ELFT> struct, and let it
have a
> pointer to _gp_disp symbol. And do pointer comparison to check if a
> relocation target is _gp_disp or not.
Do you suggest to pass a pointer to SymbolBody to the `relocateOne`
method and compare this pointer with something like
`Out<ELFT>::MipsGpDispSym`?

-- 
Simon Atanasyan

On Sun, Nov 22, 2015 at 6:57 AM, Simon Atanasyan <simon at atanasyan.com>
wrote:
> Separated from the "[lld] R_MIPS_HI16 / R_MIPS_LO16 calculation"
thread.
>
> On Sat, Nov 21, 2015 at 9:28 AM, Rui Ueyama <ruiu at google.com>
wrote:
> > On Fri, Nov 20, 2015 at 10:13 PM, Simon Atanasyan <simon at
atanasyan.com>
> > wrote:
> >> R_MIPS_HI16 and R_MIPS_LO16 relocations perform a special
calculation
> >> if a target symbol's name is `_gp_disp` [2]. AFAIK now in the
target
> >> `relocateOne` method there is no chance to get the traget symbol
name.
> >> Is it okay to pass the target symbol index and provide
> >> `MipsTargetInfo` access to the symbol table of the processing
input
> >> file?
> >
> >
> > One way is to add a SymbolBody* field to Out<ELFT> struct, and
let it
> have a
> > pointer to _gp_disp symbol. And do pointer comparison to check if a
> > relocation target is _gp_disp or not.
>
> Do you suggest to pass a pointer to SymbolBody to the `relocateOne`
> method and compare this pointer with something like
> `Out<ELFT>::MipsGpDispSym`?
>
Ah, I didn't realize that relocateOne doesn't take a symbol.

I'm not sure what's the simplest way, but you might want to add a new
parameter to relocateOne.
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