[llvm-commits] LLD: update the WriterELF.cpp to use newly added Atom reference data

[Sid Manning]

Is this change ok to commit?

On 09/18/12 09:14, Sid Manning wrote:
> This patch makes use of recently added relocation reference data.  The
> bulk of this is derived from the Mach-O writer.
>
>   * Adds loop to SectionChunk::write traverse references calling the
> writer's fixup handler, applyFixup.
>   * Adds method, ELFWriter::buildAtomToAddressMap to that creates a
> mapping from an atom to its runtime address.
>   * Adds method, ELFWriter::addressOfAtom to return the runtime address
> of the atom.
>
>
> Thanks,
>
> --
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> hosted by The Linux Foundation
>
>
> WriterELF.diff
>
>
>
> This patch makes use of recently added relocation reference data.
>
>   * Adds loop to SectionChunk::write traverse references calling the
>     writer's fixup handler, applyFixup.
>   * Adds method, ELFWriter::buildAtomToAddressMap to that creates a mapping
>     from an atom to its runtime address.
>   * Adds method, ELFWriter::addressOfAtom to return the runtime address of
>     the atom.
>
> Index: lib/ReaderWriter/ELF/WriterELF.cpp
> ===================================================================
> --- lib/ReaderWriter/ELF/WriterELF.cpp	(revision 164027)
> +++ lib/ReaderWriter/ELF/WriterELF.cpp	(working copy)
> @@ -425,7 +425,20 @@
>         continue;
>       uint8_t *atomContent = chunkBuffer + std::get<1>(ai);
>       std::copy_n(content.data(), contentSize, atomContent);
> -    // TODO Apply fixups to file buffer
> +
> +    for (const Reference *ref : *std::get<0>(ai)){
> +      uint32_t offset = ref->offsetInAtom();
> +      uint64_t targetAddress = 0;
> +
> +      if ( ref->target() != nullptr )
> +         targetAddress = _writer.addressOfAtom(ref->target());
> +
> +      uint64_t fixupAddress = _writer.addressOfAtom(std::get<0>(ai)) + offset;
> +      _writer.kindHandler()->applyFixup(ref->kind(), ref->addend(),
> +&atomContent[offset],
> +                                        fixupAddress,
> +                                        targetAddress);
> +    }
>     }
>   }
>   //
> @@ -685,8 +698,9 @@
>     typedef object::Elf_Shdr_Impl<target_endianness, is64Bits>  Elf_Shdr;
>     ELFWriter(const WriterOptionsELF&options);
>     virtual error_code writeFile(const lld::File&File, StringRef path);
> +  uint64_t addressOfAtom(const Atom *atom);
>     ArrayRef<Chunk<target_endianness, is64Bits>*>  chunks() { return _chunks; }
> -  KindHandler *kindHandler() { return _referenceKindHandler; }
> +  KindHandler *kindHandler() { return _referenceKindHandler.get(); }
>
>     std::vector<SectionChunk<target_endianness, is64Bits>*>  sectionChunks() {
>       return _sectionChunks ;
> @@ -699,11 +713,18 @@
>   private:
>     void build(const lld::File&file);
>     void createChunks(const lld::File&file);
> +  void buildAtomToAddressMap();
>     void assignFileOffsets();
>     const WriterOptionsELF&_options;
> +
> +/// \brief AtomToAddress: Is a mapping from an Atom to the address where
> +/// it will live in the output file.
> +  typedef llvm::DenseMap<const Atom*, uint64_t>  AtomToAddress;
> +
>     ELFStringSectionChunk<target_endianness, is64Bits>  *_shstrtable ;
>     std::unique_ptr<KindHandler>  _referenceKindHandler;
>     ELFSectionHeaderChunk<target_endianness, is64Bits>  *_sectionHeaderChunk;
> +  AtomToAddress _atomToAddress;
>     std::vector<Chunk<target_endianness, is64Bits>*>  _chunks;
>     const DefinedAtom *_entryAtom;
>     std::vector<SectionChunk<target_endianness, is64Bits>*>  _sectionChunks;
> @@ -725,6 +746,7 @@
>     // Create objects for each chunk.
>     createChunks(file);
>     assignFileOffsets();
> +  buildAtomToAddressMap();
>   }
>
>   template<support::endianness target_endianness, bool is64Bits>
> @@ -794,7 +816,21 @@
>     _chunks.push_back(_shstrtable);
>   }
>
> +template<support::endianness target_endianness, bool is64Bits>
> +void ELFWriter<target_endianness, is64Bits>
> +              ::buildAtomToAddressMap () {
>
> +// _atomToAddress is a DenseMap that maps an atom its file address.
> +// std::get<1>(ai) is the offset from the start of the section to the atom.
> +  for (auto&chunk : _sectionChunks){
> +    for (auto&ai : chunk->atoms() ) {
> +      _atomToAddress[std::get<0>(ai)] = chunk->address() + std::get<1>(ai);
> +    }
> +  }
> +
> +
> +}
> +
>   template<support::endianness target_endianness, bool is64Bits>
>   void ELFWriter<target_endianness, is64Bits>::assignFileOffsets() {
>     DEBUG_WITH_TYPE("WriterELF-layout", dbgs()
> @@ -844,6 +880,11 @@
>     return buffer->commit();
>   }
>
> +template<support::endianness target_endianness, bool is64Bits>
> +uint64_t ELFWriter<target_endianness, is64Bits>
> +                    ::addressOfAtom(const Atom *atom) {
> +  return _atomToAddress[atom];
> +}
>   } // namespace elf
>
>   Writer *createWriterELF(const WriterOptionsELF&options) {


-- 
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hosted by The Linux Foundation