[PATCH] D28956: [LLD][ELF] Add support for local symbols in Synthetic Sections

[Peter Smith via llvm-commits]

Thanks for the comments.

Yes they can be casts, I've made that change.

I think it would be possible to make a common base class. I did think
about it at the time but was unsure whether it would have made the
patch more difficult to understand. I can have another go to see if I
can come up with something better.

Peter

On 24 January 2017 at 23:59, Rafael Avila de Espindola
<rafael.espindola at gmail.com> wrote:
> Peter Smith via Phabricator <reviews at reviews.llvm.org> writes:
>
>> +void ARMTargetInfo::addPltHeaderSymbols(InputSectionData* ISD) const {
>> +  auto* IS = dyn_cast<InputSection<ELF32LE>>(ISD);
>
> Can this be a cast<>?
>
>> +  addSyntheticLocal("$a", STT_NOTYPE, 0, 0, IS);
>> +  addSyntheticLocal("$d", STT_NOTYPE, 16, 0, IS);
>> +}
>> +
>>  void ARMTargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr,
>>                               uint64_t PltEntryAddr, int32_t Index,
>>                               unsigned RelOff) const {
>> @@ -1748,6 +1756,13 @@
>>    write32le(Buf + 12, GotEntryAddr - L1 - 8);
>>  }
>>
>> +void ARMTargetInfo::addPltSymbols(InputSectionData* ISD, uint64_t Off) const
>> +{
>> +  auto* IS = dyn_cast<InputSection<ELF32LE>>(ISD);
>
> and this?
>
>> +  addSyntheticLocal("$a", STT_NOTYPE, Off, 0, IS);
>> +  addSyntheticLocal("$d", STT_NOTYPE, Off + 12, 0, IS);
>> +}
>> +
>>  RelExpr ARMTargetInfo::getThunkExpr(RelExpr Expr, uint32_t RelocType,
>>                                      const InputFile *File,
>>                                      const SymbolBody &S) const {
>
>> +  return S;
>> +}
>> +
>>  static size_t getHashSize() {
>>    switch (Config->BuildId) {
>>    case BuildIdKind::Fast:
>> @@ -1441,6 +1453,15 @@
>>    return Target->PltHeaderSize + Entries.size() * Target->PltEntrySize;
>>  }
>>
>> +template <class ELFT> void PltSection<ELFT>::addSymbols() {
>> +  Target->addPltHeaderSymbols(this);
>> +  size_t Off = Target->PltHeaderSize;
>> +  for (size_t I = 0; I < Entries.size(); ++I) {
>> +    Target->addPltSymbols(this, Off);
>> +    Off += Target->PltEntrySize;
>> +  }
>> +}
>> +
>>  template <class ELFT>
>>  IpltSection<ELFT>::IpltSection()
>>      : SyntheticSection<ELFT>(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS, 16,
>> @@ -1471,6 +1492,14 @@
>>    return Entries.size() * Target->PltEntrySize;
>>  }
>>
>> +template <class ELFT> void IpltSection<ELFT>::addSymbols() {
>> +  size_t Off = 0;
>> +  for (size_t I = 0; I < Entries.size(); ++I) {
>> +    Target->addPltSymbols(this, Off);
>> +    Off += Target->PltEntrySize;
>> +  }
>> +}
>
> Would it be possible to add a common base class to PltSection and
> Ipltsection and share this code?
>
> These can be done after commit, LGTM.
>
> Cheers,
> Rafael