Re: [Tinycc-devel] status of x86-64

[grischka]

shinichiro.h wrote:
> Hi,
>
> > I like this idea. But unfortunately, this needs some fixes for
> > x86-64. On x86-64, relocation may fail when the distance between
> > caller and callee is larger than 32bit. In such case, x86-64 TCC
> > generates PLT and GOT during relocation and it requires extra memory.
> > Anyway, I'll fix this.

Hm, does that mean we support programs larger than 2GB? 4GB?

> I've just checked this fix in. This fix includes the fix for order of
> relocate_syms and return offset. Please revert this change if I'm
> missing something.

As to relocate_syms runned twice, it is just meant to check symbols
already in the 1st pass, so the user doesn't have to check the
return value of tcc_relocate twice.  That's the only reason.

As to "runtime_plt_and_got", well, I don't know much about PLT/GOT
but it looks like tccpe.c:1129 is doing something similar.  Basically
it makes an indirect "jmp" and puts a reloc entry on the address
such that it gets fixed later during normal relocate_section.

It means that the jmp table need to be build BEFORE relocation,
however isn't that what build_got_entries() is doing already, anyway?
Couldn't it be used to add the needed entries for TCC_OUTPUT_MEMORY,
too?  (Maybe I'm just naive)

--- grischka