HA: [lld] r251526 - [ELF2] R_X86_64_COPY relocation implemented

[George Rimar via llvm-commits]

>> +  // Can have offset if requires copy relocation.
>> +  uintX_t OffsetInBSS = 0;
>> +  bool NeedsCopy = false;
>
>You can drop the bool by initializing OffsetInBSS to -1 and using that
>to mean that copy relocation is not needed, no?

I dont think it will be enough. In void Writer<ELFT>::scanRelocs() method E->NeedsCopy flag is used to determine
if rela.dyn entry is needed for SharedSymbol or not. Each such copy relocation for symbol should be added to rela.dyn only once
and that is for what this flag was initially added I think.

if (auto *E = dyn_cast<SharedSymbol<ELFT>>(Body)) {
  if (E->NeedsCopy)
    continue;
  E->NeedsCopy = Target->relocNeedsCopy(Type, *Body);
}
....
Out<ELFT>::RelaDyn->addReloc({C, RI});


>> +    const Elf_Sym &Sym = C->Sym;
>> +    // We don't know the exact alignment requirement for the data copied by a
>> +    // copy relocation, so align that to 16 byte boundaries that should be large
>> +    // enough unconditionally.
>> +    Off = RoundUpToAlignment(Off, 16);
>> +    C->OffsetInBSS = Off;
>> +    Off += Sym.st_size;
>
>The alignment of a symbol is less than or equal to the alignment of
>the section it came from. You can use the alignment of the section in
>here.

I`ll review that idea later.