Method writeStringSection

lib/Bytecode/Writer/BytecodeWriter.cpp:255–290

  }

  LogicalResult writeStringSection(raw_ostream &stream) {
    SmallVector<char> buffer;
    llvm::raw_svector_ostream sectionStream(buffer);
    EncodingWriter sectionWriter(sectionStream);
    sectionWriter.writeVarInt(stringIndexMap.size());
    // Align the string section
    uint64_t alignmentNeeded = alignof(uint32_t);
    sectionWriter.alignTo(alignmentNeeded);

    // Save the current position to fix up offsets later.
    auto offsetsPtr = sectionWriter.tell();

    // Reserve space for the offset table (filled later).
    for (size_t i = 0; i < stringIndexMap.size(); ++i)
      sectionWriter.writeLE<uint32_t>(0);

    // Write each string and record its starting offset.
    SmallVector<uint32_t> finalOffsets;
    finalOffsets.reserve(stringIndexMap.size());

    uint32_t running = 0;
    for (const auto &str : stringIndexMap) {
      finalOffsets.push_back(running);
      sectionWriter.write(str.first);
      running += str.first.size();
    }

    // Copy the pre-computed offsets into the reserved slot.
    std::copy_n(finalOffsets.begin(), finalOffsets.size(),
                reinterpret_cast<uint32_t *>(buffer.data() + offsetsPtr));

    writeSectionHeader(stream, Bytecode::Section::String, buffer.size(),
                       sectionWriter.getRequiredAlignment());
    stream.write(buffer.data(), buffer.size());
    return success();
  }

private:
  llvm::MapVector<StringRef, uint64_t> stringIndexMap;