Method Finish

extern/re2/re2/compile.cc:1139–1183

}

Prog* Compiler::Finish(Regexp* re) {
  if (failed_)
    return NULL;

  if (prog_->start() == 0 && prog_->start_unanchored() == 0) {
    // No possible matches; keep Fail instruction only.
    ninst_ = 1;
  }

  // Hand off the array to Prog.
  prog_->inst_ = std::move(inst_);
  prog_->size_ = ninst_;

  prog_->Optimize();
  prog_->Flatten();
  prog_->ComputeByteMap();

  if (!prog_->reversed()) {
    std::string prefix;
    bool prefix_foldcase;
    if (re->RequiredPrefixForAccel(&prefix, &prefix_foldcase) &&
        !prefix_foldcase) {
      prog_->prefix_size_ = prefix.size();
      prog_->prefix_front_ = prefix.front();
      prog_->prefix_back_ = prefix.back();
    }
  }

  // Record remaining memory for DFA.
  if (max_mem_ <= 0) {
    prog_->set_dfa_mem(1<<20);
  } else {
    int64_t m = max_mem_ - sizeof(Prog);
    m -= prog_->size_*sizeof(Prog::Inst);  // account for inst_
    if (prog_->CanBitState())
      m -= prog_->size_*sizeof(uint16_t);  // account for list_heads_
    if (m < 0)
      m = 0;
    prog_->set_dfa_mem(m);
  }

  Prog* p = prog_;
  prog_ = NULL;
  return p;
}

// Converts Regexp to Prog.
Prog* Regexp::CompileToProg(int64_t max_mem) {